Biology : Skin barrier formation and caspase-14
A protein known as caspase-14 has been identified as the enzyme involved in the protection of the skin against UVB damage and water loss, according to a study.
The involvement of caspase-family members in programmed cell death and inflammation is well understood but, a function for caspase-14 had previously not been identified. Using caspase-14 knockout mice, Wim Declercq and colleagues show that caspase-14 is responsible for the initial processing of profillagrin to fillagrin. Fillagrin is responsible for aggregating keratin and other proteins in the upper layers of the epidermis to form the stratum corneum – a layer of flattened dead-cell remnants that creates a protective barrier for the skin. The controlled processing of profillagrin to produce fillagrin ultimately maintains the integrity of the epidermis. In mice lacking caspase-14, their skin exhibits a defective stratum corneum and is more sensitive to water loss and UVB photodamage.
The identification of caspase-14 and its role in skin-barrier formation opens avenues for the pharmaceutical manipulation of this process to prevent the damage induced by UVB, the primary agent responsible for sunburn and skin ageing.
Author contact:
Wim Declercq (Ghent University, Belgium)
Tel: +32 9 33 13 660; E-mail: wim.declercq@dmbr.ugent.be
...And Control of all fates
Cell Biology investigates how pluripotency, the ability of a stem cell to differentiate into every cell type of the adult organism, is regulated.
Understanding how stem cells maintain their pluripotent state has involved the characterisation of a multitude of transcription factors – the proteins that determine whether a specific gene is expressed or not. Pluripotency in embryonic stem cells was thought to be controlled primarily by the transcription factors Oct3/4 and Sox2, as these proteins were believed to activate Oct-Sox enhancers – regulatory regions that determine the expression of pluripotent stem cell-specific genes. Shinji Masui and colleagues used mutant mice lacking the Sox2 gene to show that although Sox2 is needed for stem cell pluripotency, it is not required for the enhancers to function and in fact governs the expression of Oct3/4. The authors went on to show that this regulation is indirect, as Sox2 controls the expression of a number of transcription factors that in turn regulate Oct3/4 expression.
This study illustrates the precise regulation of pluripotency by key proteins, and reorders the hierarchy of these factors with Sox2 as the master regulator — another small step towards a complete understanding of stem cell biology.
Author contact:
Shinji Masui (International Medical Centre of Japan, Tokyo, Japan)
Tel: +81 3 3202 7181; E-mail: masui@ri.imcj.go.jp
The dual role of BRCA2 in DNA repair
The dual role of the gene BRCA2 in DNA repair is described in two independent studies. The studies from Stephen West’s and Luca Pellegrini’s groups shed light on the role of the gene, mutations of which result in predisposition to breast cancer and other malignancies.
The protein encoded by BRCA2 is involved in homologous recombination, a process whereby damaged DNA is repaired using an intact copy of DNA as a template. This process also includes the protein RAD51, which interacts directly with two different regions of BRCA2, called BRC and TR2. The BRC region had been previously suggested to be involved in terminating homologous recombination. Data from the two present studies indicate that the TR2 region can oppose the activity of BRC, suggesting that BRCA2 contains regions that both favor and disrupt homologous recombination. These activities might operate at different stages of DNA repair.
Both reports also provide insight into how the opposing activities of BRCA2 can be regulated – a phosphorylation event at TR2 results in the loss of its interaction with RAD51, acting as a turn-off switch. These findings advance our knowledge of BRCA2’s role in genetic stability, and contribute to our understanding of why mutations in BRCA2 increase the likelihood of cancer.
Author contacts:
Stephen West (Cancer Research UK, London, UK) Author paper [16]
Tel: +44 1707 625 868; E-mail: stephen.west@cancer.org.uk
Luca Pellegrini (University of Cambridge, UK) Author paper [17]
Tel: +44 1223 333 662; E-mail: luca@cryst.bioc.cam.ac.uk
Deciphering the histone code
A method to identify all modifications on histones, the proteins around which DNA is packed, is presented online. This study should allow researchers a better understanding of how genes are regulated by alterations to these proteins.
DNA holds all the information for the building blocks of life, but how a cell reads this genetic information depends on histones, and in particular on modifications to these histones. For example, the attachment of methyl groups to histones usually signals that a gene is silent, whereas the attachment of acetyl groups corresponds to gene activation. Scientists have dubbed the combinatorial use of histone modifications the ‘histone code’, but the extent to which different modifications are combined in the histone code is still unknown.
To help crack the code, Neil Kelleher and colleagues devised a method to identify all the possible modifications that occur on histones in a cell. First they separated different histone variants, depending on their degree of acetylation and methylation, by hydrophilic interaction chromatography, then they applied high-resolution tandem mass spectroscopy to identify all modifications on each variant and the exact residues carrying them. By using a mass spectrometry technique known as ‘top down,’ in which intact proteins are fragmented inside the mass spectrometer, they observed better preservation of modifications than traditional mass spectrometry methods looking at pre-digested proteins. For one particular histone alone, they found over 150 different patterns of modification.
This method helps to decipher the elements that make up the histone code and will allow researchers to relate the pattern of these modifications to the regulation of gene activity.
Author contact:
Neil Kelleher (University of Illinois at Urbana-Champaign, IL, USA)
Tel: +1 217 333 5071; E-mail: kelleher@scs.uiuc.edu
Sunday, May 27, 2007
A red-letter day for brain connectivity
Insights into grapheme-colour synesthesia are presented in a paper of Neuroscience. People with this condition – who see a cascade of colours associated with individual letters when looking at a page of text – appear to have more neural connections in areas of the brain involved in word processing and binding perceptions together.
Romke Rouw and Steven Scholte used a technique called diffusion tensor imaging (DTI) to look at brain differences between grapheme-colour synesthetes and healthy controls without this condition. DTI allows non-invasive visualisation of the white matter tracts, or axons, connecting neural cell bodies. The researchers found that synesthetes had more axons connecting three brain areas: the right fusiform gyrus, near regions involved in word and colour processing, and the left intraparietal sulcus and frontal cortex, both part of a network of regions involved in binding and consciousness.
The study also found differences among the synesthetes, according to how they perceived the association between words and colours. Some synesthetes, known as projectors, report stronger experiences that are projected into the external world, while others, known as associators, report weaker experiences that appear in their ‘mind’s eye’. The degree of structural connectivity in a region known as the right temporal cortex was correlated with the strength of the synesthetic experience. These results suggest a two-stage model of synesthesia, with increased connectivity in some areas being important for generating perceptual binding, and connectivity in other areas determining the intensity of the resultant perceptions.
Author contact:
Romke Rouw (University of Amsterdam, The Netherlands)
Tel: +31 20 525 6742; E-mail: R.Rouw@uva.nl
Insights into grapheme-colour synesthesia are presented in a paper of Neuroscience. People with this condition – who see a cascade of colours associated with individual letters when looking at a page of text – appear to have more neural connections in areas of the brain involved in word processing and binding perceptions together.
Romke Rouw and Steven Scholte used a technique called diffusion tensor imaging (DTI) to look at brain differences between grapheme-colour synesthetes and healthy controls without this condition. DTI allows non-invasive visualisation of the white matter tracts, or axons, connecting neural cell bodies. The researchers found that synesthetes had more axons connecting three brain areas: the right fusiform gyrus, near regions involved in word and colour processing, and the left intraparietal sulcus and frontal cortex, both part of a network of regions involved in binding and consciousness.
The study also found differences among the synesthetes, according to how they perceived the association between words and colours. Some synesthetes, known as projectors, report stronger experiences that are projected into the external world, while others, known as associators, report weaker experiences that appear in their ‘mind’s eye’. The degree of structural connectivity in a region known as the right temporal cortex was correlated with the strength of the synesthetic experience. These results suggest a two-stage model of synesthesia, with increased connectivity in some areas being important for generating perceptual binding, and connectivity in other areas determining the intensity of the resultant perceptions.
Author contact:
Romke Rouw (University of Amsterdam, The Netherlands)
Tel: +31 20 525 6742; E-mail: R.Rouw@uva.nl
Gene copy number and risk of autoimmunity
Individuals with fewer than two copies of the gene FCGR3B are more susceptible to a variety of autoimmune disorders, including lupus, according to a study.
Evidence is accumulating that, in addition to gene mutations, variation in the actual number of copies of individual genes can influence susceptibility to common diseases. It was previously shown that variation in the copy number of FCGR3B, a cell-surface receptor that contributes to the protective functions of the immune system, is associated with susceptibility to a kidney disease called glomerulonephritis. Timothy Aitman and colleagues now report that FCGR3B copy number variation is associated more broadly with autoimmune disorders, including lupus, microscopic polyangiitis, and Wegener’s granulomatosis. The small group of individuals who have no copies of FCGR3B have a dramatically elevated risk of autoimmune disease. This is among the first demonstrations that common naturally occurring variation in gene copy number can influence human susceptibility to disease.
Author contact:
Timothy Aitman (Imperial College, London, UK)
Tel: +44 208 383 4253; E-mail: t.aitman@csc.mrc.ac.uk
Individuals with fewer than two copies of the gene FCGR3B are more susceptible to a variety of autoimmune disorders, including lupus, according to a study.
Evidence is accumulating that, in addition to gene mutations, variation in the actual number of copies of individual genes can influence susceptibility to common diseases. It was previously shown that variation in the copy number of FCGR3B, a cell-surface receptor that contributes to the protective functions of the immune system, is associated with susceptibility to a kidney disease called glomerulonephritis. Timothy Aitman and colleagues now report that FCGR3B copy number variation is associated more broadly with autoimmune disorders, including lupus, microscopic polyangiitis, and Wegener’s granulomatosis. The small group of individuals who have no copies of FCGR3B have a dramatically elevated risk of autoimmune disease. This is among the first demonstrations that common naturally occurring variation in gene copy number can influence human susceptibility to disease.
Author contact:
Timothy Aitman (Imperial College, London, UK)
Tel: +44 208 383 4253; E-mail: t.aitman@csc.mrc.ac.uk
Glitter of gold traps microparticles
A simple technique for trapping suspended microparticles with a laser-illuminated array of gold microdots is demonstrated by Romain Quidant and colleagues online. The technique could prove useful for manipulating living cells in ‘lab-on-a-chip’ microfluidic systems.
Until now, the most promising approach to controlling cells and other micrometre-sized particles suspended in a liquid has been with so-called optical tweezers. These devices exploit the fact that such particles are attracted to and can be trapped by a focused light field. But one of their drawbacks is that they are bulky and complex devices to set up.
The technique demonstrated by Quidant and colleagues is much simpler. It relies on the fact that when a gold microdot or other metallic microstructure is illuminated with light, it will concentrate the optical field in its vicinity, similar in effect to the focusing power of a lens. By setting out an array of gold microdots on a glass slide and illuminating it with a laser, the authors effectively create an array of optical tweezers, which they use to trap microparticles suspended in a fluid droplet placed on the slide. Moreover, they show that they can use the array to selectively trap particles of a specific size from a collection of two different sizes, by controlling the size of the gold dots.
Author contact:
Romain Quidant (Institut de Ciencies Fotoniques, Barcelona, Spain)
Tel: +34 93 55 34 076; E-mail: romain.quidant@icfo.es
A simple technique for trapping suspended microparticles with a laser-illuminated array of gold microdots is demonstrated by Romain Quidant and colleagues online. The technique could prove useful for manipulating living cells in ‘lab-on-a-chip’ microfluidic systems.
Until now, the most promising approach to controlling cells and other micrometre-sized particles suspended in a liquid has been with so-called optical tweezers. These devices exploit the fact that such particles are attracted to and can be trapped by a focused light field. But one of their drawbacks is that they are bulky and complex devices to set up.
The technique demonstrated by Quidant and colleagues is much simpler. It relies on the fact that when a gold microdot or other metallic microstructure is illuminated with light, it will concentrate the optical field in its vicinity, similar in effect to the focusing power of a lens. By setting out an array of gold microdots on a glass slide and illuminating it with a laser, the authors effectively create an array of optical tweezers, which they use to trap microparticles suspended in a fluid droplet placed on the slide. Moreover, they show that they can use the array to selectively trap particles of a specific size from a collection of two different sizes, by controlling the size of the gold dots.
Author contact:
Romain Quidant (Institut de Ciencies Fotoniques, Barcelona, Spain)
Tel: +34 93 55 34 076; E-mail: romain.quidant@icfo.es
Cancer genomics: Modelling instability
A mouse model that for the first time mimics the levels of genomic instability in human cancers is presented online. The authors show that mouse and human tumours show similar genetic alterations, and suggest that future research should use this mouse model to understand the genetics of human cancer better.
Ronald DePinho and colleagues engineered lymphoma-prone mice with chromosomal instability to assess the usefulness of mouse models in cancer gene discovery. Using a comparative genomics approach they identified mutated genes in the model that are also altered in human T-cell acute lymphoblastic lymphomas and/or in a diverse range of other tumours. The researchers demonstrate a complexity and comparability in the human and mouse oncogenes that they believe means mouse models of tumours with a high degree of genomic instability will be a valuable resource for investigating complex human cancer genomes.
Author contact:
Ronald A DePinho (Dana Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 6085; E-mail: ron_depinho@dfci.harvard.edu
A mouse model that for the first time mimics the levels of genomic instability in human cancers is presented online. The authors show that mouse and human tumours show similar genetic alterations, and suggest that future research should use this mouse model to understand the genetics of human cancer better.
Ronald DePinho and colleagues engineered lymphoma-prone mice with chromosomal instability to assess the usefulness of mouse models in cancer gene discovery. Using a comparative genomics approach they identified mutated genes in the model that are also altered in human T-cell acute lymphoblastic lymphomas and/or in a diverse range of other tumours. The researchers demonstrate a complexity and comparability in the human and mouse oncogenes that they believe means mouse models of tumours with a high degree of genomic instability will be a valuable resource for investigating complex human cancer genomes.
Author contact:
Ronald A DePinho (Dana Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 6085; E-mail: ron_depinho@dfci.harvard.edu
Evolution: Paddlefish clues to limb development
The limbs of tetrapods — land-living vertebrates — are usually thought to have been evolutionary innovations unique to that group. However, traces of limbs can be found in the development of primitive ray-finned fishes, according to a report.
The perceived uniqueness of the tetrapod limb may be a reflection of comparisons with fishes, notably the zebrafish (Danio rerio), which is often used as a model organism in embryological studies. However, the zebrafish is rather highly evolved, meaning that rather than lacking vestiges of limbs to begin with, it could have lost them during its ancestry. This latter possibility seems most likely following Neil Shubin and colleagues' study of Hox-gene expression in the development of the fins of a 'living fossil', the paddlefish Polyodon spathula.
Polyodon is one of the few relics of a type of bony fish common in the seas in the Palaeozoic era, more than 250 million years ago. Hox-gene expression in the developing fins of Polyodon shows patterns long considered to be tetrapod hallmarks. This finding demonstrates that some aspects of limb development are primitive and held in common by all bony fish — but have been lost in highly evolved fishes such as the zebrafish.
CONTACT
Neil Shubin (University of Chicago, IL, USA)
Tel: +1 773 834 7472; E-mail: nshubin@uchicago.edu
The limbs of tetrapods — land-living vertebrates — are usually thought to have been evolutionary innovations unique to that group. However, traces of limbs can be found in the development of primitive ray-finned fishes, according to a report.
The perceived uniqueness of the tetrapod limb may be a reflection of comparisons with fishes, notably the zebrafish (Danio rerio), which is often used as a model organism in embryological studies. However, the zebrafish is rather highly evolved, meaning that rather than lacking vestiges of limbs to begin with, it could have lost them during its ancestry. This latter possibility seems most likely following Neil Shubin and colleagues' study of Hox-gene expression in the development of the fins of a 'living fossil', the paddlefish Polyodon spathula.
Polyodon is one of the few relics of a type of bony fish common in the seas in the Palaeozoic era, more than 250 million years ago. Hox-gene expression in the developing fins of Polyodon shows patterns long considered to be tetrapod hallmarks. This finding demonstrates that some aspects of limb development are primitive and held in common by all bony fish — but have been lost in highly evolved fishes such as the zebrafish.
CONTACT
Neil Shubin (University of Chicago, IL, USA)
Tel: +1 773 834 7472; E-mail: nshubin@uchicago.edu
Optical materials: Semiconducting nanocrystals light up the way
A new type of nanocrystal that can be used as a laser material is reported in Nature magazine. 'Soft' optical materials like this can easily be processed in solution, offering flexibility for laser design, and the devices may find use in applications including lab-on-a-chip technologies and quantum information processing devices.
Semiconductor nanocrystals have excellent light-emitting properties, making them good candidates for use in laser applications. But achieving the crucial condition for lasing — optical amplification — has proved problematic: normally the nanocrystals need to contain at least two excitons (electron–hole pairs, which are the precursors for light emission in semiconductors), but owing to the nanocrystal’s tiny size, the excitons annihilate each other before optical amplification can occur.
Victor I. Klimov and colleagues circumvent this problem by designing nanocrystals with cores and shells made from different semiconductor materials, in such a way that electrons and holes are physically isolated from each other. In such engineered nanocrystals, only one exciton per nanocrystal is required for optical amplification, as has here been experimentally demonstrated by Klimov and colleagues. This opens the door to practical use in laser applications.
CONTACT
Victor I. Klimov (Los Alamos National Laboratory, NM, USA)
Tel: +1 505 665 8284; E-mail: klimov@lanl.gov
Todd D. Krauss (University of Rochester, NY, USA) N&V author
Tel: +1 585 275 5093; E-mail: krauss@chem.rochester.edu
A new type of nanocrystal that can be used as a laser material is reported in Nature magazine. 'Soft' optical materials like this can easily be processed in solution, offering flexibility for laser design, and the devices may find use in applications including lab-on-a-chip technologies and quantum information processing devices.
Semiconductor nanocrystals have excellent light-emitting properties, making them good candidates for use in laser applications. But achieving the crucial condition for lasing — optical amplification — has proved problematic: normally the nanocrystals need to contain at least two excitons (electron–hole pairs, which are the precursors for light emission in semiconductors), but owing to the nanocrystal’s tiny size, the excitons annihilate each other before optical amplification can occur.
Victor I. Klimov and colleagues circumvent this problem by designing nanocrystals with cores and shells made from different semiconductor materials, in such a way that electrons and holes are physically isolated from each other. In such engineered nanocrystals, only one exciton per nanocrystal is required for optical amplification, as has here been experimentally demonstrated by Klimov and colleagues. This opens the door to practical use in laser applications.
CONTACT
Victor I. Klimov (Los Alamos National Laboratory, NM, USA)
Tel: +1 505 665 8284; E-mail: klimov@lanl.gov
Todd D. Krauss (University of Rochester, NY, USA) N&V author
Tel: +1 585 275 5093; E-mail: krauss@chem.rochester.edu
Biophysics: Clustering key to membrane remodelling
A sophisticated simulation study reveals a trick that many membrane-bound proteins could use to vastly amplify their own effect on the shape of the membranes they are interacting with.
Biological membranes are much more than passive physical barriers: changes in their shape are linked to important cellular tasks such as endocytosis and protein sorting. It’s known that specialized proteins can sense and create membrane curvature, but the energy needed to accomplish complex membrane remodelling — large changes in membrane shape or topology — is only available when several proteins act together. But how do they coordinate their action?
Kurt Kremer and colleagues now show that a single protein interacting with a membrane causes local changes in membrane shape. Importantly, this attracts other proteins in the vicinity, which then cluster together yielding enough energy for the membrane to be remodelled, allowing, for example, vesicles to be formed.
CONTACT
Kurt Kremer (Max-Planck-Institut fur Polymerforschung, Mainz, Germany)
Tel: +49 6131 379 140; E-mail: kremer@mpip-mainz.mpg.de
Michael M. Kozlov (Tel Aviv University, Israel) N&V author
Tel: +972 3 640 7863; E-mail: michk@post.tau.ac.il
A sophisticated simulation study reveals a trick that many membrane-bound proteins could use to vastly amplify their own effect on the shape of the membranes they are interacting with.
Biological membranes are much more than passive physical barriers: changes in their shape are linked to important cellular tasks such as endocytosis and protein sorting. It’s known that specialized proteins can sense and create membrane curvature, but the energy needed to accomplish complex membrane remodelling — large changes in membrane shape or topology — is only available when several proteins act together. But how do they coordinate their action?
Kurt Kremer and colleagues now show that a single protein interacting with a membrane causes local changes in membrane shape. Importantly, this attracts other proteins in the vicinity, which then cluster together yielding enough energy for the membrane to be remodelled, allowing, for example, vesicles to be formed.
CONTACT
Kurt Kremer (Max-Planck-Institut fur Polymerforschung, Mainz, Germany)
Tel: +49 6131 379 140; E-mail: kremer@mpip-mainz.mpg.de
Michael M. Kozlov (Tel Aviv University, Israel) N&V author
Tel: +972 3 640 7863; E-mail: michk@post.tau.ac.il
Extreme weather: A look from the lagoon
Changes in the El Niño/Southern Oscillation and the strength of the West African monsoon have played an important part in controlling the frequency of intense hurricanes in the tropical North Atlantic over the past 5,000 years, a study suggests.
Jeffrey P. Donnelly and Jonathan D. Woodruff constructed a long-term record of intense hurricane activity in the western tropical North Atlantic Ocean. Storms associated with intense hurricanes that strike the island of Vieques in Puerto Rico deposit layers of coarse, sandy material in a lagoon, so the authors used sediment cores from the lagoon to reconstruct the frequency of intense hurricanes in this area over the last 5,000 years.
Their record shows striking similarities to records of El Niño events and rainfall in tropical Africa, suggesting that changes in the El Niño/Southern Oscillation and the strength of the West African monsoon had an important role in controlling the frequency of intense hurricanes in the tropical North Atlantic over this interval.
The lengthy time-interval studied helps to clarify the factors that control hurricane activity, because instrumental records only cover the past few decades. Furthermore, the results suggest that it is important to understand how the El Niño/Southern Oscillation and the West African monsoon will respond to future climate change to accurately predict changes in intense hurricane activity.
CONTACT
Jeffrey P. Donnelly (Woods Hole Oceanographic Institution, MA, USA)
Tel: +1 508 294 2994; E-mail: jdonnelly@whoi.edu
Changes in the El Niño/Southern Oscillation and the strength of the West African monsoon have played an important part in controlling the frequency of intense hurricanes in the tropical North Atlantic over the past 5,000 years, a study suggests.
Jeffrey P. Donnelly and Jonathan D. Woodruff constructed a long-term record of intense hurricane activity in the western tropical North Atlantic Ocean. Storms associated with intense hurricanes that strike the island of Vieques in Puerto Rico deposit layers of coarse, sandy material in a lagoon, so the authors used sediment cores from the lagoon to reconstruct the frequency of intense hurricanes in this area over the last 5,000 years.
Their record shows striking similarities to records of El Niño events and rainfall in tropical Africa, suggesting that changes in the El Niño/Southern Oscillation and the strength of the West African monsoon had an important role in controlling the frequency of intense hurricanes in the tropical North Atlantic over this interval.
The lengthy time-interval studied helps to clarify the factors that control hurricane activity, because instrumental records only cover the past few decades. Furthermore, the results suggest that it is important to understand how the El Niño/Southern Oscillation and the West African monsoon will respond to future climate change to accurately predict changes in intense hurricane activity.
CONTACT
Jeffrey P. Donnelly (Woods Hole Oceanographic Institution, MA, USA)
Tel: +1 508 294 2994; E-mail: jdonnelly@whoi.edu
Crows are smart! Research group at Keio University succeeds in drawing up the world’s first stereotaxic atlas of a crow
Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of Keio University and his group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Crows are known to be smart, and the findings proved that the pallium of the crow brain, which is related to intellectual activities, is well developed.
It has been known that the brain of a crow weighs 10-13g, very large compared to its total body weight. However, the details, such as which part of the brain is largely developed, were not clear. Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of the Faculty of Letters and their group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Recent observations had shown that crows have intelligence comparable to primates and have skills of tool-making and deceiving others. Prof. Watanabe and Associate Prof. Izawa clarified the total picture of the crow brain in detail to prove these observations, and the research can be applied in neuroscientific experiments in the future. These findings can be a breakthrough to finding out the brain evolution of animals including human beings.
1. About the stereotaxic atlas
The stereotaxic atlas is indispensable for studies of the brain. This is similar to a 3-dimensional map of a cross-section of the brain of fixed coordinates. By using this method, it is possible to identify the exact placements inside the brain. This stereotaxic atlas of the jungle crow was released on 14 May at http://www.cirm.keio.ac.jp/db/bird_brain, and will appear in “Integration of comparative neuroanatomy and comparative cognition” (Keio Univ. Press) to be published in the near future.
2. Characteristics of the crow brain
The crow is known to have a large brain compared to its body weight, and to have outstanding cognitive abilities. The stereotaxic atlas of the crow shows that brain areas called ‘pallium’ corresponding to the mammalian cortex, which controls thinking, learning and feeling, makes up a large portion of the brain, and within the ‘pallium’, the dorsal part which is related to intellectual activities, is large and well developed. This area is thought to be relevant to the association area (where multiple information such as visual or auditory signals are integrated) of the cerebral cortex in mammal brains including humans, and enables the crow to process complicated information. Crows are known to be smart, and the new completion of the stereotaxic atlas of the crow proved this.
3. Methods for drawing up the stereotaxic atlas
The research started with developing a stereotaxic holder to keep the crow brain in a fixed position. Stereotaxic holders for mice/rats and pigeons are commercially available, but for crows, it had to be custom-made. The brain was frozen under -20℃ and sliced into thin plates. The plates were then stained with cresyl violet for Nissle substance and luxol fast blue for myelinated fibers. The plates were examined under a microscope to separate the nerve cells according to density. At the same time, imaging of the plates were done to create an atlas and to name each group of nerve cells. The same process was repeated for all the plates of the crow brain from the front to the back, sliced in the thickness of 1mm. The atlas was completed by combining these data.
This research is part of the 21st Century COE Program Keio University Graduate School Toward an Integrated Methodology for the Study of the Mind. The Center of Excellence was selected by the 21st Century COE (Center of Excellence) Program of the Ministry of Education, Culture, Sports, Science and Technology toward an integrated methodology for the study of the mind. The newest findings in neuroscience, behavioral genetics are combined with philosophy, linguistics, information science and representational theories.
Inquiries: Mr. Ogawa or Ms. Kawagoe, Office of Communications and Public Relations, Keio University
TEL: ＋81-3-5427-1541 FAX: ＋81-3-5441-7640
E-mail: m-koho@adst.keio.ac.jp http://www.keio.ac.jp/
Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of Keio University and his group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Crows are known to be smart, and the findings proved that the pallium of the crow brain, which is related to intellectual activities, is well developed.
It has been known that the brain of a crow weighs 10-13g, very large compared to its total body weight. However, the details, such as which part of the brain is largely developed, were not clear. Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of the Faculty of Letters and their group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Recent observations had shown that crows have intelligence comparable to primates and have skills of tool-making and deceiving others. Prof. Watanabe and Associate Prof. Izawa clarified the total picture of the crow brain in detail to prove these observations, and the research can be applied in neuroscientific experiments in the future. These findings can be a breakthrough to finding out the brain evolution of animals including human beings.
1. About the stereotaxic atlas
The stereotaxic atlas is indispensable for studies of the brain. This is similar to a 3-dimensional map of a cross-section of the brain of fixed coordinates. By using this method, it is possible to identify the exact placements inside the brain. This stereotaxic atlas of the jungle crow was released on 14 May at http://www.cirm.keio.ac.jp/db/bird_brain, and will appear in “Integration of comparative neuroanatomy and comparative cognition” (Keio Univ. Press) to be published in the near future.
2. Characteristics of the crow brain
The crow is known to have a large brain compared to its body weight, and to have outstanding cognitive abilities. The stereotaxic atlas of the crow shows that brain areas called ‘pallium’ corresponding to the mammalian cortex, which controls thinking, learning and feeling, makes up a large portion of the brain, and within the ‘pallium’, the dorsal part which is related to intellectual activities, is large and well developed. This area is thought to be relevant to the association area (where multiple information such as visual or auditory signals are integrated) of the cerebral cortex in mammal brains including humans, and enables the crow to process complicated information. Crows are known to be smart, and the new completion of the stereotaxic atlas of the crow proved this.
3. Methods for drawing up the stereotaxic atlas
The research started with developing a stereotaxic holder to keep the crow brain in a fixed position. Stereotaxic holders for mice/rats and pigeons are commercially available, but for crows, it had to be custom-made. The brain was frozen under -20℃ and sliced into thin plates. The plates were then stained with cresyl violet for Nissle substance and luxol fast blue for myelinated fibers. The plates were examined under a microscope to separate the nerve cells according to density. At the same time, imaging of the plates were done to create an atlas and to name each group of nerve cells. The same process was repeated for all the plates of the crow brain from the front to the back, sliced in the thickness of 1mm. The atlas was completed by combining these data.
This research is part of the 21st Century COE Program Keio University Graduate School Toward an Integrated Methodology for the Study of the Mind. The Center of Excellence was selected by the 21st Century COE (Center of Excellence) Program of the Ministry of Education, Culture, Sports, Science and Technology toward an integrated methodology for the study of the mind. The newest findings in neuroscience, behavioral genetics are combined with philosophy, linguistics, information science and representational theories.
Inquiries: Mr. Ogawa or Ms. Kawagoe, Office of Communications and Public Relations, Keio University
TEL: ＋81-3-5427-1541 FAX: ＋81-3-5441-7640
E-mail: m-koho@adst.keio.ac.jp http://www.keio.ac.jp/
Saturday, May 19, 2007
IMMUNOLOGY : Another immune evasion strategy by HIV
Interaction of the human immunodeficiency virus (HIV) with dendritic cells—a specialized type of immune cell—circumvents immune activation and greatly enhances infection of T lymphocytes, reports a study to be published in the June issue of Nature Immunology.
Dendritic cells are required to initiate immune responses, and as targets of HIV infection, these cells are important contributors to HIV pathogenesis. Alison Simmons and colleagues evaluated the effect of HIV interaction with DC-SIGN, a protein receptor found largely on the surface of dendritic cells. HIV binding to DC-SIGN elicited a signalling pathway that prevented dendritic cells from actively stimulating subsequent immune responses. In addition, the authors show that HIV–DC-SIGN interaction can lead to transfer of virus to nearby T lymphocytes that then become infected leading to a burst of HIV production.
These results reveal how HIV can both evade dendritic cell immune activity and amplify its own replication. With nearly 40 million people world-wide currently living with HIV-AIDS, understanding the myriad ways that HIV can modulate immune responses is of paramount importance.
Author contact:
Alison Simmons (Weatherall Institute of Molecular Medicine, Oxford, UK)
Tel: +44 1865 222 616; E-mail: asimmons@hammer.imm.ox.ac.uk
Additional contact for comment:
Anthony Cunningham (Westmead Millennium Institute, Australia)
Tel: +61 2 9845 9005; E-mail: tony_cunningham@wmi.usyd.edu.au
Interaction of the human immunodeficiency virus (HIV) with dendritic cells—a specialized type of immune cell—circumvents immune activation and greatly enhances infection of T lymphocytes, reports a study to be published in the June issue of Nature Immunology.
Dendritic cells are required to initiate immune responses, and as targets of HIV infection, these cells are important contributors to HIV pathogenesis. Alison Simmons and colleagues evaluated the effect of HIV interaction with DC-SIGN, a protein receptor found largely on the surface of dendritic cells. HIV binding to DC-SIGN elicited a signalling pathway that prevented dendritic cells from actively stimulating subsequent immune responses. In addition, the authors show that HIV–DC-SIGN interaction can lead to transfer of virus to nearby T lymphocytes that then become infected leading to a burst of HIV production.
These results reveal how HIV can both evade dendritic cell immune activity and amplify its own replication. With nearly 40 million people world-wide currently living with HIV-AIDS, understanding the myriad ways that HIV can modulate immune responses is of paramount importance.
Author contact:
Alison Simmons (Weatherall Institute of Molecular Medicine, Oxford, UK)
Tel: +44 1865 222 616; E-mail: asimmons@hammer.imm.ox.ac.uk
Additional contact for comment:
Anthony Cunningham (Westmead Millennium Institute, Australia)
Tel: +61 2 9845 9005; E-mail: tony_cunningham@wmi.usyd.edu.au
Gene combinations influence AIDS progression
Different combinations of genetic variants of two modulators of the innate human immune system strongly influence AIDS progression in HIV-positive individuals, according to a study.
Natural killer cells are part of the antiviral immune response, and their activity is controlled by receptors called KIRs that are present on the cell surface. The KIR receptors that inhibit natural killer cell activity (KIR3DL1) are triggered by HLA-B molecules, which are presented by other cells of the immune system. Mary Carrington and colleagues examined variation in the genes encoding KIR3DL1 and HLA-B in more than 1,500 HIV-positive individuals, and found that particular combinations of variants conferred protection against AIDS progression.
These results may explain at least part of the variability in progression of the disease in infected individuals. The authors also note that the observed rapid evolution of these genes may be driven by pathogens such as HIV.
Author contact:
Mary Carrington (National Cancer Institute, Frederick, MD, USA)
Tel: +1 301 846 1390; E-mail: carringt@ncifcrf.gov
Different combinations of genetic variants of two modulators of the innate human immune system strongly influence AIDS progression in HIV-positive individuals, according to a study.
Natural killer cells are part of the antiviral immune response, and their activity is controlled by receptors called KIRs that are present on the cell surface. The KIR receptors that inhibit natural killer cell activity (KIR3DL1) are triggered by HLA-B molecules, which are presented by other cells of the immune system. Mary Carrington and colleagues examined variation in the genes encoding KIR3DL1 and HLA-B in more than 1,500 HIV-positive individuals, and found that particular combinations of variants conferred protection against AIDS progression.
These results may explain at least part of the variability in progression of the disease in infected individuals. The authors also note that the observed rapid evolution of these genes may be driven by pathogens such as HIV.
Author contact:
Mary Carrington (National Cancer Institute, Frederick, MD, USA)
Tel: +1 301 846 1390; E-mail: carringt@ncifcrf.gov
Nanotubes sort out their left and right
Left- and right-handed carbon nanotubes can be separated from one another, according to a paper. Although nanotubes have previously been sorted on the basis of their diameter or length, this method is the first to discriminate between those with opposite helical twists.
Some molecules, which are known as ‘chiral’, can exist as mirror-image forms that cannot be superimposed on each other. Louis Pasteur was, in 1849, the first to separate such molecules, by meticulously sorting asymmetric crystals of tartaric acid by hand, using tweezers and a microscope. Following in his footsteps, Naoki Komatsu and co-workers designed pairs of chemical ‘nano-tweezers’ that can selectively pluck either left- or right-handed nanotubes from a mixture.
The ability to separate carbon nanotubes — one of nanotechnology’s most promising building blocks — in this way will lead to a better understanding of their optical properties, and may offer unique opportunities for photonics and quantum optics.
Author contact:
Naoki Komatsu (Shiga University of Medical Science, Otsu, Japan)
Tel: +81 77 548 2102; E-mail: nkomatsu@belle.shiga-med.ac.jp
Left- and right-handed carbon nanotubes can be separated from one another, according to a paper. Although nanotubes have previously been sorted on the basis of their diameter or length, this method is the first to discriminate between those with opposite helical twists.
Some molecules, which are known as ‘chiral’, can exist as mirror-image forms that cannot be superimposed on each other. Louis Pasteur was, in 1849, the first to separate such molecules, by meticulously sorting asymmetric crystals of tartaric acid by hand, using tweezers and a microscope. Following in his footsteps, Naoki Komatsu and co-workers designed pairs of chemical ‘nano-tweezers’ that can selectively pluck either left- or right-handed nanotubes from a mixture.
The ability to separate carbon nanotubes — one of nanotechnology’s most promising building blocks — in this way will lead to a better understanding of their optical properties, and may offer unique opportunities for photonics and quantum optics.
Author contact:
Naoki Komatsu (Shiga University of Medical Science, Otsu, Japan)
Tel: +81 77 548 2102; E-mail: nkomatsu@belle.shiga-med.ac.jp
CHEMICAL BIOLOGY : A little sugar for the brain
The amount of sugar on proteins inside neural cells changes in response to brain stimulation, which implicates sugar modification as a new player in brain signalling, according to a paper to be published in the June issue of Nature Chemical Biology. Changes in the levels of phosphorylation of serine and threonine residues have a well-known role in cell signalling. Although most glycosylation, or modification of proteins by the attachment of sugars, occurs on proteins outside the cell, one sugar modification, called O-GlcNAc, can be attached to serine or threonine residues of proteins inside cells. Because phosphorylation and O-GlcNAc modifications occur on exactly the same amino acid side chains, O-GlcNAc could be critical in cellular signalling. However, a lack of tools to identify the precise positions of O-GlcNAc modifications in vivo has made it difficult to investigate this hypothesis.
Linda Hsieh-Wilson and colleagues have now developed a proteomic method that uses mass spectrometry to determine in vivo O-GlcNAc levels. When rats were injected with an excitatory stimulus, the authors identified changes in the sugar levels at specific sites of proteins found in the brain. With this information, it will now be possible to investigate the exact role O-GlcNAc plays in brain function.
Author contact:
Linda Hsieh-Wilson (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 6101; E-mail: lhw@caltech.edu
The amount of sugar on proteins inside neural cells changes in response to brain stimulation, which implicates sugar modification as a new player in brain signalling, according to a paper to be published in the June issue of Nature Chemical Biology. Changes in the levels of phosphorylation of serine and threonine residues have a well-known role in cell signalling. Although most glycosylation, or modification of proteins by the attachment of sugars, occurs on proteins outside the cell, one sugar modification, called O-GlcNAc, can be attached to serine or threonine residues of proteins inside cells. Because phosphorylation and O-GlcNAc modifications occur on exactly the same amino acid side chains, O-GlcNAc could be critical in cellular signalling. However, a lack of tools to identify the precise positions of O-GlcNAc modifications in vivo has made it difficult to investigate this hypothesis.
Linda Hsieh-Wilson and colleagues have now developed a proteomic method that uses mass spectrometry to determine in vivo O-GlcNAc levels. When rats were injected with an excitatory stimulus, the authors identified changes in the sugar levels at specific sites of proteins found in the brain. With this information, it will now be possible to investigate the exact role O-GlcNAc plays in brain function.
Author contact:
Linda Hsieh-Wilson (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 6101; E-mail: lhw@caltech.edu
Unexpected biodiversity springs from the depths
Five-hundred and eighty-five new species of crustacean have been found in the depths of the Southern Ocean, thanks to three sampling expeditions set up as part of the ANDEEP (Antarctic benthic deep-sea biodiversity) project. Unexpected levels of biodiversity were found in this dark and largely unstudied place, challenging assumptions that deep sea diversity is depressed in this area.
On their expeditions, Angelika Brandt and colleagues collected biological specimens and environmental data from different regions 774 to 6,348 metres under the surface of the Weddell Sea and adjacent areas. The Weddell Sea is an important source of deep water for the rest of the ocean and provides a possible route for species to enter the deep water. In line with this, the team found deep-sea faunas that were also found in adjacent shelf communities and in other oceans.
They spotted 674 species of isopod — a diverse order of crustaceans — of which over 80% were new to science. In some regions, groups of slope-dwelling isopods and marine worms included species that had invaded from the Southern Ocean’s deep continental shelf. Species living in the deepest parts of the Weddell Sea tended to have strong links to other oceans, particularly if they were good dispersers, like certain amoeboids. But poor dispersers, such as isopods, nematode worms and seed shrimps, were Southern Ocean-specific species.
CONTACT
Angelika Brandt (University of Hamburg, Germany)
Tel: +49 40 42838 2278; E-mail: abrandt@zoologie.uni-hamburg.de
Five-hundred and eighty-five new species of crustacean have been found in the depths of the Southern Ocean, thanks to three sampling expeditions set up as part of the ANDEEP (Antarctic benthic deep-sea biodiversity) project. Unexpected levels of biodiversity were found in this dark and largely unstudied place, challenging assumptions that deep sea diversity is depressed in this area.
On their expeditions, Angelika Brandt and colleagues collected biological specimens and environmental data from different regions 774 to 6,348 metres under the surface of the Weddell Sea and adjacent areas. The Weddell Sea is an important source of deep water for the rest of the ocean and provides a possible route for species to enter the deep water. In line with this, the team found deep-sea faunas that were also found in adjacent shelf communities and in other oceans.
They spotted 674 species of isopod — a diverse order of crustaceans — of which over 80% were new to science. In some regions, groups of slope-dwelling isopods and marine worms included species that had invaded from the Southern Ocean’s deep continental shelf. Species living in the deepest parts of the Weddell Sea tended to have strong links to other oceans, particularly if they were good dispersers, like certain amoeboids. But poor dispersers, such as isopods, nematode worms and seed shrimps, were Southern Ocean-specific species.
CONTACT
Angelika Brandt (University of Hamburg, Germany)
Tel: +49 40 42838 2278; E-mail: abrandt@zoologie.uni-hamburg.de
Materials: Silicon in a spin
The first silicon-based spintronics device reported. Spintronics, an emerging technology that uses the quantum spin states as well as (or instead of) the charge states of electrons, offers another level of control over electronic devices. So with silicon already at the forefront of conventional electronics, devices like this could find themselves integrated with standard silicon technology.
Researchers have been trying to make devices that can transport electronic signals with all of the electrons spun in one direction only. But finding the right combinations of materials to do this efficiently has proved tricky. Ian Appelbaum and colleagues have achieved this by sandwiching an extra layer inside their device. The extra layer, made from aluminium and iron cobalt sits between an insulating barrier and the silicon, where it filters out electrons of a particular spin.
CONTACT
Ian Appelbaum (University of Delaware, Newark, DE, USA)
Tel: +1 302 831 3295; E-mail: appelbaum@ee.udel.edu
Igor Zutic (State University of New York at Buffalo, NY, USA) N&V author
Tel: +1 716 645 2017 x183; E-mail: zigor@buffalo.edu
The first silicon-based spintronics device reported. Spintronics, an emerging technology that uses the quantum spin states as well as (or instead of) the charge states of electrons, offers another level of control over electronic devices. So with silicon already at the forefront of conventional electronics, devices like this could find themselves integrated with standard silicon technology.
Researchers have been trying to make devices that can transport electronic signals with all of the electrons spun in one direction only. But finding the right combinations of materials to do this efficiently has proved tricky. Ian Appelbaum and colleagues have achieved this by sandwiching an extra layer inside their device. The extra layer, made from aluminium and iron cobalt sits between an insulating barrier and the silicon, where it filters out electrons of a particular spin.
CONTACT
Ian Appelbaum (University of Delaware, Newark, DE, USA)
Tel: +1 302 831 3295; E-mail: appelbaum@ee.udel.edu
Igor Zutic (State University of New York at Buffalo, NY, USA) N&V author
Tel: +1 716 645 2017 x183; E-mail: zigor@buffalo.edu
Infectious diseases: Global early-warning system needed
Researchers are calling for a global early-warning system to identify the sources of future human infectious disease. analysis compares the origins of temperate and tropical infectious diseases, and highlights how little we know about their evolution.
Most major human infectious diseases have animal origins, yet we continue to be bombarded by new animal pathogens, jumping across species barriers. So Jared Diamond and colleagues want to see a systematic ongoing global effort monitoring for emergent animal pathogens that could infect humans. People with high levels of exposure to wild animals, such as hunters, zoo workers and wildlife veterinarians, should be regularly screened, they say.
The team made their request after comparing the characteristics and origins of 15 temperate (such as whooping cough) and 10 tropical diseases (such as cholera). Most of the diseases studied arose in Africa, Asia and Europe, but the reasons for their emergence differed between regions — infections from animal and insect vectors, for example, were more common in the tropics.
The review reveals “big gaps in our understanding” of the origins of even established major infectious diseases, such as AIDS, cholera and tuberculosis. So alongside a global early-warning system for new human infectious diseases, the authors would also like to see more research to clarify the origins of existing infectious diseases. Such work could boost understanding of how diseases emerge and suggest new laboratory models for studying public health threats.
CONTACT
Jared Diamond (University of California, Los Angeles, CA, USA)
Tel: +1 310 825 6177; E-mail: jdiamond@geog.ucla.edu
Nathan Wolfe (University of California, Los Angeles, CA, USA) Co-author
Tel: +1 310 794 7538; E-mail: nwolfe@ucla.edu
Researchers are calling for a global early-warning system to identify the sources of future human infectious disease. analysis compares the origins of temperate and tropical infectious diseases, and highlights how little we know about their evolution.
Most major human infectious diseases have animal origins, yet we continue to be bombarded by new animal pathogens, jumping across species barriers. So Jared Diamond and colleagues want to see a systematic ongoing global effort monitoring for emergent animal pathogens that could infect humans. People with high levels of exposure to wild animals, such as hunters, zoo workers and wildlife veterinarians, should be regularly screened, they say.
The team made their request after comparing the characteristics and origins of 15 temperate (such as whooping cough) and 10 tropical diseases (such as cholera). Most of the diseases studied arose in Africa, Asia and Europe, but the reasons for their emergence differed between regions — infections from animal and insect vectors, for example, were more common in the tropics.
The review reveals “big gaps in our understanding” of the origins of even established major infectious diseases, such as AIDS, cholera and tuberculosis. So alongside a global early-warning system for new human infectious diseases, the authors would also like to see more research to clarify the origins of existing infectious diseases. Such work could boost understanding of how diseases emerge and suggest new laboratory models for studying public health threats.
CONTACT
Jared Diamond (University of California, Los Angeles, CA, USA)
Tel: +1 310 825 6177; E-mail: jdiamond@geog.ucla.edu
Nathan Wolfe (University of California, Los Angeles, CA, USA) Co-author
Tel: +1 310 794 7538; E-mail: nwolfe@ucla.edu
Planetary science: Enceladus' daily grind
Scientists may have worked out what powers the plumes of gas seen escaping from the surface of one of Saturn's moons. The energy may be generated by massive ice sheets grinding together, with the vapour produced being released through rifts that open and close periodically, papers suggest.
When Cassini flew by Enceladus, a small icy satellite of Saturn, a couple of years ago, cameras snapped active vapour plumes thought to emanate from rifts in the crust dubbed 'tiger stripes.' Francis Nimmo and colleagues now suggest that these 'tiger stripes' are like strike-slip fault zones, with sheets of ice grinding back and forth against one another. This, they say, could generate enough energy to power the gas plumes.
Terry A. Hurford and colleagues show that as Enceladus orbits Saturn, the parent planet's tides make the satellite's ice flex. This, they believe, causes the 'tiger stripes' to open and close periodically, exposing volatiles and allowing them to be released.
Tidal heating was previously proposed as a potential mechanism to explain Enceladus' vapour plumes, but scientists debate whether the energy generated from tidal heating is sufficient. The two new papers offer a plausible alternative.
CONTACT
Francis Nimmo (University of California, Santa Cruz, CA, USA) Author paper [2]
Tel: +1 831 459 1783; E-mail: fnimmo@es.ucsc.edu
Terry A. Hurford (NASA Goddard Space Flight Center, Greenbelt, MD, USA) Author paper [3]
Tel: +1 301 614 6455; E-mail: hurfordt@core2.gsfc.nasa.gov
Andrew J. Dombard (Johns Hopkins University, Laurel, MD, USA) N&V author
Tel: +1 240 228 1651; E-mail: andrew.dombard@jhuapl.edu
Scientists may have worked out what powers the plumes of gas seen escaping from the surface of one of Saturn's moons. The energy may be generated by massive ice sheets grinding together, with the vapour produced being released through rifts that open and close periodically, papers suggest.
When Cassini flew by Enceladus, a small icy satellite of Saturn, a couple of years ago, cameras snapped active vapour plumes thought to emanate from rifts in the crust dubbed 'tiger stripes.' Francis Nimmo and colleagues now suggest that these 'tiger stripes' are like strike-slip fault zones, with sheets of ice grinding back and forth against one another. This, they say, could generate enough energy to power the gas plumes.
Terry A. Hurford and colleagues show that as Enceladus orbits Saturn, the parent planet's tides make the satellite's ice flex. This, they believe, causes the 'tiger stripes' to open and close periodically, exposing volatiles and allowing them to be released.
Tidal heating was previously proposed as a potential mechanism to explain Enceladus' vapour plumes, but scientists debate whether the energy generated from tidal heating is sufficient. The two new papers offer a plausible alternative.
CONTACT
Francis Nimmo (University of California, Santa Cruz, CA, USA) Author paper [2]
Tel: +1 831 459 1783; E-mail: fnimmo@es.ucsc.edu
Terry A. Hurford (NASA Goddard Space Flight Center, Greenbelt, MD, USA) Author paper [3]
Tel: +1 301 614 6455; E-mail: hurfordt@core2.gsfc.nasa.gov
Andrew J. Dombard (Johns Hopkins University, Laurel, MD, USA) N&V author
Tel: +1 240 228 1651; E-mail: andrew.dombard@jhuapl.edu
Regeneration: Hope for new hair
Adult mice can regenerate hair follicles and hair. The results help resolve a 50-year-long debate and may aid in the design of new treatments for wounds, hair loss and other degenerative skin disorders.
For half a century, most people believed that mammalian hair follicles form only during development, and that loss of adult follicles is permanent. George Cotsarelis and colleagues now show this is not the case, at least for adult mice with skin wounds. Wounding, they report, triggers new hair-producing follicles to form. Exposure to Wnt signalling — a genetic pathway involved in normal hair follicle development and cycling — following wounding increases the number of regenerated hair follicles. And Wnt signalling inhibition after regrowth of the epithelium prevents new follicles from forming.
The results suggest that mammalian skin can respond to wounding with plasticity and a much greater regenerative capacity than was previously believed. It's thought that wounding triggers an embryonic-like state in the skin which provides a window for hair follicle regeneration via the Wnt signalling pathway.
CONTACT
George Cotsarelis (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 898 9967; E-mail: cotsarel@mail.med.upenn.edu
Cheng-Ming Chuong (University of Southern California, Los Angeles, CA, USA) N&V author
Tel: +1 323 442 1296; E-mail: chuong@pathfinder.usc.edu
Adult mice can regenerate hair follicles and hair. The results help resolve a 50-year-long debate and may aid in the design of new treatments for wounds, hair loss and other degenerative skin disorders.
For half a century, most people believed that mammalian hair follicles form only during development, and that loss of adult follicles is permanent. George Cotsarelis and colleagues now show this is not the case, at least for adult mice with skin wounds. Wounding, they report, triggers new hair-producing follicles to form. Exposure to Wnt signalling — a genetic pathway involved in normal hair follicle development and cycling — following wounding increases the number of regenerated hair follicles. And Wnt signalling inhibition after regrowth of the epithelium prevents new follicles from forming.
The results suggest that mammalian skin can respond to wounding with plasticity and a much greater regenerative capacity than was previously believed. It's thought that wounding triggers an embryonic-like state in the skin which provides a window for hair follicle regeneration via the Wnt signalling pathway.
CONTACT
George Cotsarelis (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 898 9967; E-mail: cotsarel@mail.med.upenn.edu
Cheng-Ming Chuong (University of Southern California, Los Angeles, CA, USA) N&V author
Tel: +1 323 442 1296; E-mail: chuong@pathfinder.usc.edu
Saturday, May 12, 2007
Bagoong: Good for the Brain
A study shows that the traditional fish/shrimp paste condiment, or bagoong, of the Philippines contains the beneficial omega-3 fatty acids. In its analysis, it was found that among the samples of bagoong, shrimp paste has the highest omega-3 content.
The famous Bagoong, also referred to as fish or shrimp paste, is one of the traditional flavor extenders used in the Philippines. It has several variations according to the type of fish used, color, and taste. Bagoong is prepared by fermenting the fish or shrimp in high concentrations of salt for several months. Consumed either as a complement of green mangoes or as a seasoning to some Filipino delicacies such as pinakbet, little is known about the nutritional content of these condiments since they are usually sold without labels in local markets.
Fish and other marine food resources are known to be good sources of long-chain ω-3 (omega-3) polyunsaturated fatty acids. One in particular is the all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), a variant of the long-chain ω-3 fatty acid, which is essential to the neural development of growing infants especially in brain and retina development. Sufficient amount of DHA is required for an active brain function throughout a human’s lifespan. DHA has also been found to lower blood pressure and chances of occurrence of heart disease and mental illness. Though high levels of DHA are produced during pregnancy and during the first two months of infancy, the normal human body condition can only manufacture these fatty acids metabolically in small amounts. DHA must then be acquired from the diet or produced through the consumption of ω-3 precursors such as α-linolenic acid found in seeds and nuts.
The composition of bagoong suggests the possibility that the said condiment may be a dietary resource of long-chain ω-3 polyunsaturated fatty acids. In the study “Polyunsaturated fatty acid contents of some traditional fish and shrimp paste condiments of the Philippines,” scientists Nemesio Montaño, Grace Gavino and Victor C. Gavino assess the fatty acid composition of various types of fish and shrimp paste in reaction to the brine solution used for fermentation.
Montaño’s team gathered samples of six types of fish and shrimp paste condiments from a public market in Bolinao, Pangasinan located at Western Luzon of the Philippines. The vendors of these products were interviewed regarding their preparation process of bagoong. The general preparation of bagoong according to them is that fish or shrimp fry are deposited alternately in layers with salt in ratios of three to four parts of salt to one part of fish or shrimp fry. The mixture is then incubated at ambient temperature in a specific period of time depending on the fish type used. The fish types used in the collected samples were verified through visual investigation. The samples were found to be made from Dalagang bukid (Fusiliers, Caesio spp.), Dilis (Silver sprat, Spratelloides gracillis), Padas-1 (Fuscescens rabbitfish, Siganus fuscescens), Padas-2 (Forktail rabbitfish, Siganus argenteus), Terong (Fusiliers, Pterocaesio spp.) and Alamang (Shrimp fry, Acetes spp.). Samples were analyzed fresh or freeze-dried. The composition of fresh untreated alamang was also compared with the composition of salt-treated alamang.
Fatty acid composition, salt content, moisture and water activity of the fish/shrimp paste samples were measured to examine if the salinity of the paste condiments and the oxidation process significantly affect the fatty acid content of the fish and shrimp fry. Ash and fat content were also studied to look further into the composition of bagoong. The salt content of the samples was determined using the Mohr Method [1] while moisture was calculated from the sample’s weight loss when dried. Water activity was determined by equilibration with the salt solution. The dried samples were then reduced to ashes to measure the ash content. Fat content was measured by Soxhlet extraction [2] of the freeze-dried samples and the fatty acid composition was determined using an adaptation of a direct methylation procedure on the sample followed by gas chromatography.
Findings show that the salt content of the bagoong samples does not tally with the ratio of salt to fish/shrimp fry given by the vendors. Salinity was found to range from 19 to 24%, which greatly differs from the 60 to 80% accounted from the vendors’ statement. The alamang condiment was also found to contain the highest level of DHA ω-3 polyunsaturated fatty acids among the samples followed by Padas-1. The Dalagang bukid paste condiment, on the other hand, has the lowest. According to Dr. Montaño, this may be explained by the phytoplanktons and bacteria the shrimp fry consume which could have produced the high levels of long-chain polyunsaturated fatty acids.
References:
1. Thomson Healthcare, PDRhealth. “Docahexaenoic Acid (DHA).”
2. DHA/EPA Omega-3 Institute. “DHA for Optimal Brain and Visual Functioning.“
3. The Kushi Institute of Europe, Encyclopedia. “Fats.”
4. University of Canterbury, Christchurch New Zealand. “Determination of Chloride Ion Concentration by Titration (Mohr’s Method).”
By MMRParreño
___________________________________________________________________
[1] Mohr Method is the process of determining chlorides in bagoong sample using titration with silver nitrate and indicator potassium chromate. The pH level of the sample to be tested should be between 6.5 to 10 for more accurate readings.
[2] Soxhlet Extraction is the process of extracting fat from the freeze-dried bagoong sample using low-boiling petroleum ether as solvent.
A study shows that the traditional fish/shrimp paste condiment, or bagoong, of the Philippines contains the beneficial omega-3 fatty acids. In its analysis, it was found that among the samples of bagoong, shrimp paste has the highest omega-3 content.
The famous Bagoong, also referred to as fish or shrimp paste, is one of the traditional flavor extenders used in the Philippines. It has several variations according to the type of fish used, color, and taste. Bagoong is prepared by fermenting the fish or shrimp in high concentrations of salt for several months. Consumed either as a complement of green mangoes or as a seasoning to some Filipino delicacies such as pinakbet, little is known about the nutritional content of these condiments since they are usually sold without labels in local markets.
Fish and other marine food resources are known to be good sources of long-chain ω-3 (omega-3) polyunsaturated fatty acids. One in particular is the all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), a variant of the long-chain ω-3 fatty acid, which is essential to the neural development of growing infants especially in brain and retina development. Sufficient amount of DHA is required for an active brain function throughout a human’s lifespan. DHA has also been found to lower blood pressure and chances of occurrence of heart disease and mental illness. Though high levels of DHA are produced during pregnancy and during the first two months of infancy, the normal human body condition can only manufacture these fatty acids metabolically in small amounts. DHA must then be acquired from the diet or produced through the consumption of ω-3 precursors such as α-linolenic acid found in seeds and nuts.
The composition of bagoong suggests the possibility that the said condiment may be a dietary resource of long-chain ω-3 polyunsaturated fatty acids. In the study “Polyunsaturated fatty acid contents of some traditional fish and shrimp paste condiments of the Philippines,” scientists Nemesio Montaño, Grace Gavino and Victor C. Gavino assess the fatty acid composition of various types of fish and shrimp paste in reaction to the brine solution used for fermentation.
Montaño’s team gathered samples of six types of fish and shrimp paste condiments from a public market in Bolinao, Pangasinan located at Western Luzon of the Philippines. The vendors of these products were interviewed regarding their preparation process of bagoong. The general preparation of bagoong according to them is that fish or shrimp fry are deposited alternately in layers with salt in ratios of three to four parts of salt to one part of fish or shrimp fry. The mixture is then incubated at ambient temperature in a specific period of time depending on the fish type used. The fish types used in the collected samples were verified through visual investigation. The samples were found to be made from Dalagang bukid (Fusiliers, Caesio spp.), Dilis (Silver sprat, Spratelloides gracillis), Padas-1 (Fuscescens rabbitfish, Siganus fuscescens), Padas-2 (Forktail rabbitfish, Siganus argenteus), Terong (Fusiliers, Pterocaesio spp.) and Alamang (Shrimp fry, Acetes spp.). Samples were analyzed fresh or freeze-dried. The composition of fresh untreated alamang was also compared with the composition of salt-treated alamang.
Fatty acid composition, salt content, moisture and water activity of the fish/shrimp paste samples were measured to examine if the salinity of the paste condiments and the oxidation process significantly affect the fatty acid content of the fish and shrimp fry. Ash and fat content were also studied to look further into the composition of bagoong. The salt content of the samples was determined using the Mohr Method [1] while moisture was calculated from the sample’s weight loss when dried. Water activity was determined by equilibration with the salt solution. The dried samples were then reduced to ashes to measure the ash content. Fat content was measured by Soxhlet extraction [2] of the freeze-dried samples and the fatty acid composition was determined using an adaptation of a direct methylation procedure on the sample followed by gas chromatography.
Findings show that the salt content of the bagoong samples does not tally with the ratio of salt to fish/shrimp fry given by the vendors. Salinity was found to range from 19 to 24%, which greatly differs from the 60 to 80% accounted from the vendors’ statement. The alamang condiment was also found to contain the highest level of DHA ω-3 polyunsaturated fatty acids among the samples followed by Padas-1. The Dalagang bukid paste condiment, on the other hand, has the lowest. According to Dr. Montaño, this may be explained by the phytoplanktons and bacteria the shrimp fry consume which could have produced the high levels of long-chain polyunsaturated fatty acids.
References:
1. Thomson Healthcare, PDRhealth. “Docahexaenoic Acid (DHA).”
2. DHA/EPA Omega-3 Institute. “DHA for Optimal Brain and Visual Functioning.“
3. The Kushi Institute of Europe, Encyclopedia. “Fats.”
4. University of Canterbury, Christchurch New Zealand. “Determination of Chloride Ion Concentration by Titration (Mohr’s Method).”
By MMRParreño
___________________________________________________________________
[1] Mohr Method is the process of determining chlorides in bagoong sample using titration with silver nitrate and indicator potassium chromate. The pH level of the sample to be tested should be between 6.5 to 10 for more accurate readings.
[2] Soxhlet Extraction is the process of extracting fat from the freeze-dried bagoong sample using low-boiling petroleum ether as solvent.
Friday, May 11, 2007
Gender-specific differences fuel biodiversity
Many factors, such as habitat, behaviour and diet, contribute to biological diversity. But researchers now have an unexpected addition to this list — sexual differences. A study of the Anolis lizards of the Greater Antilles suggests that morphological differences between males and females are linked to increased biodiversity.
The Anolis lizards of Puerto Rico, Jamaica, Cuba and Hispaniola evolved independently on their respective islands into species that occupy particular niches, such as the short-legged twig dwellers and the long-legged open space dwellers. But males and females of the same species can be very different — in some species the sexes are the same size, but in others adult males can be three times bigger than females.
Marguerite A. Butler and colleagues studied five sexually dimorphic characteristics from male and female adults of different niche specialists living on two of the islands. They find that sexual dimorphism contributes substantially to biodiversity, helping to fuel the bursts of ‘adaptive radiation’ that produced the different niche-adapted species.
Most studies of adaptive radiation ignore sexually dimorphic traits, the authors say. But its place in evolutionary ecology should not be underestimated.
CONTACT
Marguerite A. Butler (University of Hawaii at Manoa, Honolulu, HI, USA)
Tel: +1 808 956 4713; E-mail: mbutler@hawaii.edu
Many factors, such as habitat, behaviour and diet, contribute to biological diversity. But researchers now have an unexpected addition to this list — sexual differences. A study of the Anolis lizards of the Greater Antilles suggests that morphological differences between males and females are linked to increased biodiversity.
The Anolis lizards of Puerto Rico, Jamaica, Cuba and Hispaniola evolved independently on their respective islands into species that occupy particular niches, such as the short-legged twig dwellers and the long-legged open space dwellers. But males and females of the same species can be very different — in some species the sexes are the same size, but in others adult males can be three times bigger than females.
Marguerite A. Butler and colleagues studied five sexually dimorphic characteristics from male and female adults of different niche specialists living on two of the islands. They find that sexual dimorphism contributes substantially to biodiversity, helping to fuel the bursts of ‘adaptive radiation’ that produced the different niche-adapted species.
Most studies of adaptive radiation ignore sexually dimorphic traits, the authors say. But its place in evolutionary ecology should not be underestimated.
CONTACT
Marguerite A. Butler (University of Hawaii at Manoa, Honolulu, HI, USA)
Tel: +1 808 956 4713; E-mail: mbutler@hawaii.edu
Oceanography: Oceanic short circuit
Researchers have discovered a 'short circuit' in the circulation of the world's oceans that allows cold waters that sink to the abyss to return to the surface more rapidly than previously thought. Understanding oceanic circulation is important because it transports heat, carbon and nutrients around the globe and therefore plays a central role in Earth's climate.
Ocean mixing in the current that flows around Antarctica has a key role in global ocean circulation as it influences the rate at which water sinking to the deep ocean at high latitudes returns to the surface in the Southern Ocean. But the rates of mixing processes that occur in the current and the induced upwelling are not well known. Alberto C. Naveira Garabato and colleagues studied the spread of helium released from submarine volcanoes to measure the rates of mixing and upwelling in the southwest Atlantic sector of the current.
Their results indicate that the rough topography of the ocean floor in this region leads to both rapid mixing across density surfaces and rapid upwelling along density surfaces, which together create a 'short circuit' in the global oceanic overturning circulation.
CONTACT
Alberto C. Naveira Garabato (University of Southampton, UK)
Tel: +44 23 8059 2680; E-mail: acng@noc.soton.ac.uk
Researchers have discovered a 'short circuit' in the circulation of the world's oceans that allows cold waters that sink to the abyss to return to the surface more rapidly than previously thought. Understanding oceanic circulation is important because it transports heat, carbon and nutrients around the globe and therefore plays a central role in Earth's climate.
Ocean mixing in the current that flows around Antarctica has a key role in global ocean circulation as it influences the rate at which water sinking to the deep ocean at high latitudes returns to the surface in the Southern Ocean. But the rates of mixing processes that occur in the current and the induced upwelling are not well known. Alberto C. Naveira Garabato and colleagues studied the spread of helium released from submarine volcanoes to measure the rates of mixing and upwelling in the southwest Atlantic sector of the current.
Their results indicate that the rough topography of the ocean floor in this region leads to both rapid mixing across density surfaces and rapid upwelling along density surfaces, which together create a 'short circuit' in the global oceanic overturning circulation.
CONTACT
Alberto C. Naveira Garabato (University of Southampton, UK)
Tel: +44 23 8059 2680; E-mail: acng@noc.soton.ac.uk
Planetary science: Extrasolar planet mirror ball
An extrasolar 'hot Jupiter' planet may act like a giant mirror ball, re-radiating almost all of its incident energy back out to space, suggests a paper. But a second paper, tells a very different story, making 'hot Jupiters' seem all the more intriguing and complex.
'Hot Jupiters' are extrasolar planets whose mass is similar to that of Jupiter, but which orbit much closer to their parent star. Joseph Harrington and colleagues studied one such planet and found that it acts almost as a mirror, a bizarre observation as one would expect the planet to absorb at least some heat.
But Heather A. Knutson and co-workers found that a different 'hot Jupiter' can redistribute heat around its surface. The team effectively crudely 'mapped' the temperature distribution across the planet. Their data suggest that energy absorbed by the dayside of the planet can be fairly efficiently redistributed throughout the planet's atmosphere.
CONTACT
Joseph Harrington (University of Central Florida, Orlando, FL, USA) Author paper [2]
Tel: +1 407 823 3416; E-mail: jharring@phsyics.ucf.edu
Heather A. Knutson (Harvard University, Cambridge, MA, USA) Author paper [3]
Tel: +1 617 223 1723; E-mail: hknutson@cfa.harvard.edu
Adam Burrows (University of Arizona, Tucson, AZ, USA) N&V author
Tel: +1 520 621 1795; E-mail: aburrows@as.arizona.edu
An extrasolar 'hot Jupiter' planet may act like a giant mirror ball, re-radiating almost all of its incident energy back out to space, suggests a paper. But a second paper, tells a very different story, making 'hot Jupiters' seem all the more intriguing and complex.
'Hot Jupiters' are extrasolar planets whose mass is similar to that of Jupiter, but which orbit much closer to their parent star. Joseph Harrington and colleagues studied one such planet and found that it acts almost as a mirror, a bizarre observation as one would expect the planet to absorb at least some heat.
But Heather A. Knutson and co-workers found that a different 'hot Jupiter' can redistribute heat around its surface. The team effectively crudely 'mapped' the temperature distribution across the planet. Their data suggest that energy absorbed by the dayside of the planet can be fairly efficiently redistributed throughout the planet's atmosphere.
CONTACT
Joseph Harrington (University of Central Florida, Orlando, FL, USA) Author paper [2]
Tel: +1 407 823 3416; E-mail: jharring@phsyics.ucf.edu
Heather A. Knutson (Harvard University, Cambridge, MA, USA) Author paper [3]
Tel: +1 617 223 1723; E-mail: hknutson@cfa.harvard.edu
Adam Burrows (University of Arizona, Tucson, AZ, USA) N&V author
Tel: +1 520 621 1795; E-mail: aburrows@as.arizona.edu
Genetics: Marsupial genome sequenced
The first high-quality draft of a marsupial genome sequence is revealed.The genome of the grey, short-tailed opossum (Monodelphis domestica) offers interesting insights into the genetics of the immune system and the X chromosome.
Kerstin Lindblad-Toh and colleagues identified a wide range of immune genes. Some seem to be marsupial-specific, whereas others are shared with placental mammals. This, alongside the discovery of a novel type of T-cell receptor, indicates that marsupials had already evolved a complex immune system when they diverged from the placental mammal lineage some 180 million years ago — a suggestion that is at odds with previous claims of a primitive immune system.
The results also suggest that random inactivation of the X chromosome — a phenomenon seen in placental mammals whereby one random copy of the X chromosome is switched off to avoid a double dose of 'X genes' — appeared alongside the evolution of a complex genetic locus called the X inactivation centre (XIC). The XIC is lacking in the opossum genome, a finding that may help to explain why, in the opossum, it's always the paternally derived X chromosome that is silenced.
The newly sequenced genome seems to contain 18,000–20,000 protein-coding genes, most of which have counterparts in placental mammals. Opossum-specific genes mostly originate from the expansion and rapid turnover of gene families involved in immunity, sensory perception and detoxification.
The sequencing of the opossum genome marks an important point in genetics research and not just because of the special place occupied by the marsupial in the evolutionary tree. The animals provide a good model of malignant melanoma, and are useful in studies of regeneration because newborns can heal complete transections of spinal cord.
CONTACT
Kerstin Lindblad-Toh (Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Nicole Davis (Scientific Communications Specialist, Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Tel: +1 617 258 0952; E-mail: ndavis@broad.mit.edu
Geoff Spencer (Public Affairs Specialist, National Human Genome Research Institute, NIH, Bethesda, MD, USA)
Tel: +1 301 451 8325; E-mail: spencerg@mail.nih.gov
Leo Goodstadt (MRC Functional Genetics Unit, University of Oxford, UK) Co-author
This author can be contacted through the MRC press office:
Tel: +44 20 7637 6011; E-mail: press.office@headoffice.mrc.ac.uk
The first high-quality draft of a marsupial genome sequence is revealed.The genome of the grey, short-tailed opossum (Monodelphis domestica) offers interesting insights into the genetics of the immune system and the X chromosome.
Kerstin Lindblad-Toh and colleagues identified a wide range of immune genes. Some seem to be marsupial-specific, whereas others are shared with placental mammals. This, alongside the discovery of a novel type of T-cell receptor, indicates that marsupials had already evolved a complex immune system when they diverged from the placental mammal lineage some 180 million years ago — a suggestion that is at odds with previous claims of a primitive immune system.
The results also suggest that random inactivation of the X chromosome — a phenomenon seen in placental mammals whereby one random copy of the X chromosome is switched off to avoid a double dose of 'X genes' — appeared alongside the evolution of a complex genetic locus called the X inactivation centre (XIC). The XIC is lacking in the opossum genome, a finding that may help to explain why, in the opossum, it's always the paternally derived X chromosome that is silenced.
The newly sequenced genome seems to contain 18,000–20,000 protein-coding genes, most of which have counterparts in placental mammals. Opossum-specific genes mostly originate from the expansion and rapid turnover of gene families involved in immunity, sensory perception and detoxification.
The sequencing of the opossum genome marks an important point in genetics research and not just because of the special place occupied by the marsupial in the evolutionary tree. The animals provide a good model of malignant melanoma, and are useful in studies of regeneration because newborns can heal complete transections of spinal cord.
CONTACT
Kerstin Lindblad-Toh (Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Nicole Davis (Scientific Communications Specialist, Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Tel: +1 617 258 0952; E-mail: ndavis@broad.mit.edu
Geoff Spencer (Public Affairs Specialist, National Human Genome Research Institute, NIH, Bethesda, MD, USA)
Tel: +1 301 451 8325; E-mail: spencerg@mail.nih.gov
Leo Goodstadt (MRC Functional Genetics Unit, University of Oxford, UK) Co-author
This author can be contacted through the MRC press office:
Tel: +44 20 7637 6011; E-mail: press.office@headoffice.mrc.ac.uk
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