Interesting Science

What's 34 centimeters (13.39 inches) long, likes the cold and has an interorbital pit with two openings? The answer is Cryothenia amphitreta, a newly discovered Antarctic fish discovered by a member of a research team from the University of Illinois at Urbana-Champaign. (A pen-and-ink drawing of the fish can be seen here)

"The fish was placed into the genus Cryothenia because of its overall similarity to the notothenioid Cryothenia peninsulae that has only been found near the Antarctica Peninsula. The species name was chosen to help researchers easily distinguish the two species in the genus Cryothenia, which translates from Greek as 'from the cold,' while amphitreta literally means 'an orifice with two openings.'" (U. of I.)

The new species of nototheniid fish, Cryothenia amphitreta, is detailed in the December issue of the quarterly journal Copeia [1] (published by The American Society of Ichthyologists and Herpetologists). Paul A. Cziko, a research specialist who had graduated with bachelor's degrees in animal biology and biochemistry from Illinois six months earlier, and research diver Kevin Hoefling, discovered it in McMurdo Sound [3] in the Ross Sea region of Antarctica in November 2004.

They were diving in the area in search of eggs laid by naked dragonfish (Gymnodraco acuticeps) for a study, published earlier this year [2], about levels of antifreeze proteins in newly hatched notothenioids in the salty icy waters where the temperature is rarely above the freezing point of seawater.

"We just came across this fish," Cziko recalled. "It was just sitting on the bottom, like most other fish in the area. There are only about a dozen species that swim in the area, with four to five easily distinguishable species. This one jumped out at us. First of all it was pretty big, and it looked quite different than the others."

Cziko and Hoefling guided the egg-laden fish into a mesh bag and surfaced.

"It was about twice as big as what you normally see swimming around," said Arthur L. DeVries, a professor of animal biology who many years earlier had discovered antifreeze proteins in notothenioids. "Its profile was much different than other common local notothenioids. Its center part is much higher. Most of the other species in the area have big heads and have bodies that taper back narrowly."

Cziko and co-author Chi-Hing (Christina) Cheng, professor of animal biology, studied the purple-gold-colored fish, comparing its measurements and perch-like appearance with all known species of fish that inhabit the icy waters of Antarctica. X-ray radiographs of bone structures were taken at the U. of I. College of Veterinary Medicine.

The new fish, which DeVries theorizes may have been looking for a place to lay its eggs in a flat, clear area near an intake pipe that feeds water into the McMurdo Station, was placed into the genus Cryothenia because of its overall similarity to the notothenioid Cryothenia peninsulae that has only been found near the Antarctica Peninsula.

Although bigger in pelvic-fin length and body size, as well as having more vertebrae, what sets C amphitreta apart from C. peninsulae is head morphology, specifically in the area between the eyes.

The new fish has a "wide, well-defined, two-holed interorbital pit divided by a raised medial ridge, scales anterior to this depression in the interorbital region, and a dark pigmentation of the mouth, gill and body cavity linings," Cziko and Cheng wrote.

The species name was chosen to help researchers easily distinguish the two species in the genus Cryothenia, which translates from Greek as "from the cold," while amphitreta literally means "an orifice with two openings."

"Even though we know a lot about Antarctica," Cziko said, "we still don't know everything about the ecosystems and the animals in them. There's probably a lot more to be learned about how these fish evolved and survived."

The area where C. amphitreta was found is the most-frequented location in McMurdo Sound explored by divers and fished with hand lines. DeVries has been going to the site for more than 40 years.

The new fish was located on a large flat rock in water that was minus 1.91 degrees Celsius and 20 meters deep.

"Art has been swimming there for more than 40 years," Cziko said. "You'd think he would have caught everything." DeVries does have an Antarctic fish named after him: Paraliparis devriesii.

National Science Foundation grants to Cheng and DeVries funded the research.

Source: University of Illinois at Urbana-Champaign PR December 19 2006

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[1] Based on the paper:

A New Species of Nototheniid (Perciformes: Notothenioidei) Fish from Mcmurdo Sound, Antarctica

Paul A. Cziko, C.-H. Christina Cheng

Copeia Volume 2006, Issue 4 (December 2006)
DOI: 10.1643/0045-8511(2006)6[752:ANSONP]2.0.CO;2

Abstract

A new species of nototheniid fish, Cryothenia amphitreta, is described from a single gravid female collected in mid-November 2004 by divers in McMurdo Sound in the Ross Sea region of Antarctica. The new species closely resembles the only known congener, C. peninsulae, collected off the west coast of the Antarctic Peninsula, but differs substantially in pelvic-fin length (13.4 vs. 19.3-24.4% SL), total vertebrae (57 vs. 50-53), body size at maturity (261 vs. 100-144 mm), and interorbital-pit morphology. The neutrally-buoyant C. amphitreta is characterized by a wide, well-defined interorbital pit divided by a raised medial ridge, scales anterior to this depression in the interorbital region, and a dark pigmentation of the mouth, gill, and body cavity linings. This species is protected against freezing by high levels of antifreeze proteins in its body fluids. Phylogenetic reconstruction using the mitochondrial NADH dehydrogenase subunit 2 (mtND2) suggests that C. amphitreta falls within the current designation of the nototheniid subfamily Trematominae.

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[2] A paper published by Proceedings of the National Academy of Sciences (PNAS):

Nonhepatic origin of notothenioid antifreeze reveals pancreatic synthesis as common mechanism in polar fish freezing avoidance

Chi-Hing C. Cheng, Paul A. Cziko, and Clive W. Evans

Published online before print June 23, 2006, 10.1073/pnas.0603796103
PNAS | July 5, 2006 | vol. 103 | no. 27 | 10491-10496

Abstract

Phylogenetically diverse polar and subpolar marine teleost fishes have evolved antifreeze proteins (AFPs) or antifreeze glycoproteins (AFGPs) to avoid inoculative freezing by internalized ice. For over three decades since the first fish antifreeze (AF) protein was discovered, many studies of teleost freezing avoidance showed hepatic AF synthesis and distribution within the circulation as pivotal in preventing the blood, and therefore the fish, from freezing. We have uncovered an important twist to this long-held paradigm: the complete absence of liver synthesis of AFGPs in any life stage of the Antarctic notothenioids, indicating that the liver plays no role in the freezing avoidance in these fishes. Instead, we found the exocrine pancreas to be the major site of AFGP synthesis and secretion in all life stages, and that pancreatic AFGPs enter the intestinal lumen via the pancreatic duct to prevent ingested ice from nucleating the hyposmotic intestinal fluids. AFGPs appear to remain undegraded in the intestinal milieu, and the composition and relative abundance of intestinal AFGP isoforms are nearly identical to serum AFGPs. Thus, the reabsorption of intact pancreas-derived intestinal AFGPs, and not the liver, is the likely source of circulatory AFGPs in notothenioid fishes. We examined diverse northern fish taxa and Antarctic eelpouts with hepatic synthesis of bloodborne AF and found that they also express secreted pancreatic AF of their respective types. The evolutionary convergence of this functional physiology underscores the hitherto largely unrecognized importance of intestinal freezing prevention in polar teleost freezing avoidance, especially in the chronically icy Antarctic waters.

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[3] Info on McMurdo Sound:

...Captain James Clark Ross (pictured) discovered the sound in February 1841 and named it after Lt. Archibald McMurdo of HMS Terror. The sound today serves as a re-supply route for cargo vessels and for aircraft that land upon floating ice airstrips near McMurdo Station. However McMurdo Station's continuous occupation by scientists and support staff since 1957-58 has turned Winter's Quarter's Bay into a markedly polluted harbor.

The pack ice that girdles the shoreline at Winter Quarters Bay and elsewhere in the sound presents a formidable obstacle to surface ships. Vessels require ice-strengthened hulls and often have to rely upon icebreaker escorts. Such extreme sea conditions have limited access by tourists, who otherwise are appearing in increasing numbers in the open waters of the Antarctica Peninsula. The few tourists who reach the McMurdo Sound find a spectacular scenery with wildlife viewing ranging from killer whales, seals, to adelie and emperor penquins...

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Permanent Link posted by John Latter @ 7:10 PM 0 comments

A hormone implicated in the onset of human puberty also appears to control reproductive activity in seasonally breeding rodents, report Indiana University Bloomington and University of California at Berkeley scientists in the March 2007 issue of Endocrinology.

The researchers present evidence that kisspeptin*, a recently discovered neuropeptide encoded by the KiSS-1 gene, mediates the decline of male Siberian hamsters' libido and reproduction as winter approaches and daylight hours wane.

'Ours isn't the first study to link the peptide to reproduction, but it is the first to connect kisspeptin to how animals interpret seasonal cues, including day length,' said IUB biologist Gregory Demas**. 'Kisspeptin likely plays an integral role in coordinating seasonal reproduction in a wide range of animals.'

Kisspeptin joins a select few proteins believed to act as switches that connect environmental changes to a physiological response.

"This peptide is poised to act as an integrator of environmental information to allow for the optimal neuroendocrine control of reproduction in vertebrates, including humans," said UC Berkeley neuroscientist Lance Kriegsfeld. "In humans and other species, if the environment is not satisfactory, sex drive will decline; kisspeptin is likely part of the pathway responsible for this regulation."

The scientists divided a population of male Siberian hamsters (Phodopus sungorus) into treatment groups: those housed in long, summer-like photoperiods and those in short, winter-like photoperiods. In a separate experiment hamsters were also treated with exogenous injections of kisspeptin after eight weeks of either short- or long-day photoperiod exposure. At the conclusion of the experimental period, scientists analyzed the hamsters' reproductive system status, blood levels of reproductive hormones, as well as the number of kisspeptin-expressing cells in the brain.

They found hamsters in wintry conditions experienced marked reductions of kisspeptin in a critical brain region important for regulating reproduction and sex behavior compared to hamsters in simulated summer conditions.

Winter hamsters, however, were just as responsive to kisspeptin, elevating a key hormone - luteinizing hormone - as much as hamsters in simulated summers. This finding indicates the ability of this hormone to turn on the reproductive switch even in the presence of cues signaling a winter, non-breeding environment.

"What is really striking is the disappearance of kisspeptin in animals experiencing winter-like days, yet the ability to respond to kisspeptin when we provide it," said Timothy Greives, lead author of the study. "These data show that the disappearance of kisspeptin in the brain is likely critical in turning off reproduction during winter."

Recent research by scientists in the U.K. and France have shown human kisspeptin triggers the release of gonadotropin-releasing hormone and luteinizing hormone, both of which are important to puberty and other sex-related functions.

"Studies in humans have shown that individuals with deficits in the receptor for kisspeptin have severe reproductive impairments," Demas said.

Kisspeptin's role in seasonal human reproduction, however, is unknown - that is, if it even has one. It is interesting to note the CDC reports fertility rates in the United States decrease rapidly in autumn. The phenomenon is particularly clear-cut among Caucasians, believed to have originated in more temperate climes.

KiSS-1 and kisspeptin were not named whimsically. They were originally associated with metastatic tumor suppression (the SS in KiSS-1 stands for "suppressor sequence"). The subsequent connection of KiSS-1 and kisspeptin to reproductive function was entirely fortuitous.

IUB biologist Ellen Ketterson and graduate student Melissa-Ann Scotti, and UC Berkeley graduate student Alex Mason and undergraduate student Jacob Levine also contributed to the research. It was funded by grants from Indiana University and UC Berkeley.

Source: Indiana University PR December 28, 2006

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Based on the Endochrinology paper:

Environmental Control of Kisspeptin: Implications for Seasonal Reproduction

By Timothy J. Greives, Alex O. Mason, Melissa-Ann L. Scotti, Jacob Levine, Ellen D. Ketterson, Lance J. Kriegsfeld, and Gregory E. Demas

Endocrinology Vol. 148, No. 3 1158-1166
Endocrinology, doi:10.1210/en.2006-1249

Abstract

The KiSS-1 gene encodes the peptide hormone kisspeptin, which acts as a principal positive regulator of the reproductive axis by directly stimulating GnRH neuron activity. To gain insight into a potential role for kisspeptin in integrating and relaying reproductively-relevant stimuli to the GnRH system, we investigated changes in kisspeptin peptide expression associated with photoperiodic changes in reproductive state, as well as pituitary and gonadal responses to peripheral kisspeptin injections. Seasonally breeding rodents undergo pronounced fluctuations in reproductive state in response to changing day lengths. In common with other rodent species, a majority of male Siberian hamsters (Phodopus sungorus) exhibit reproductive decline following exposure to short day lengths. A subset of individuals fails to respond to day length information, however, and maintains their reproductive function. We exploited these individual differences to examine whether kisspeptin may act at the interface between external stimuli and the reproductive system. Following extended exposure to short days, animals with a quiescent reproductive axis displayed a marked reduction in kisspeptin cell labeling in the AVPV, but robust kisspeptin-ir staining in the ARC. In contrast, animals with functional reproductive systems displayed high numbers of kisspeptin-ir neurons in the AVPV, but a paucity of expression in the ARC. Kisspeptin injections significantly elevated LH over pre-injection levels regardless of photoperiod or reproductive state. Collectively, these findings suggest an important role for kisspeptin in coordinating and relaying environmentally relevant information to the reproductive axis, as well as a role for this peptide in regulating seasonal changes in reproductive function.

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*Info on Kisspeptin from the Observer (July '05):

It is sealed with a kiss. Researchers have found that a protein called kisspeptin triggers the cascade of biochemical changes that leads to puberty and turns children into hormonally challenged adolescents.

The discovery raises hopes of understanding one of human biology's fundamental processes, when a young person's body is propelled towards sexual maturity, turning a normal, happy child into a sulking, spotty teenager.

More importantly, the finding could lead to the development of drugs to block the premature onset of sexuality in very young children.

The discovery also raises prospects of developing new treatments for breast and prostate cancer. These tumours are nourished by sex hormones that are in turn controlled by kisspeptin.

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**Info from Demas Lab:

The primary focus of our laboratory is in the general area of "ecological physiology". Specifically, we study of the interactions among the nervous, endocrine and immune systems and behavior in a variety of ecologically relevant environmental contexts. For example, many non-tropical organisms experience pronounced fluctuations in environmental conditions (e.g., day length, ambient temperature, food availability, social interactions) across the seasons of the year. Consequently, individuals of a wide range of species have evolved specific adaptive mechanisms to cope with seasonal fluctuations in the environment. These adaptations may be physiological (e.g., changes in energy balance, reproductive function or immunity) or behavioral (e.g., changes in foraging, migration, aggression or social behavior). The broad goal of our research is to identity the environmental and social factors contributing to seasonal changes in specific physiological and behavioral responses and to determine the neural, endocrine and immune mechanisms underlying these changes. Although this research focuses primarily on rodent species (e.g., Siberian hamsters, deer mice, voles), we also address these questions in amphibian and avian species.

Technorati: hormone, puberty, human, rodents, endocrinology, kisspeptin, gene, male, siberian, hamsters, libido, reproductive, kiss, 1, study, winter, animals, proteins, sex, system, sexual, maturity, breast, prostate, cancer, nervous, immune

Permanent Link posted by John Latter @ 1:25 PM 0 comments

In a study recently published online by the journal Developmental Biology, members of Dr. John Herr's laboratory at the University of Virginia Health System report the discovery of a new protein within a sperm's tail that could prove a key target for male contraceptive drugs.

'There's considerable interest in developing new male contraceptives,' said Herr*, who heads UVa's Center for Research in Contraceptive and Reproductive Health. 'To support this effort, our team has been searching for proteins that might serve as target sites for small-molecule drugs.'

The newly discovered protein is called sperm flagellar energy carrier (SFEC). It is the fourth in a family of proteins that perform transfer processes to help cells make and use energy. Inside the cell, these proteins operate much like a shuttle bus, binding and exchanging energy-carrying molecules known as ATP and ADP.

The discovery of SFEC has sparked interest among both basic scientists and contraceptive drug developers because of where it is located in the sperm and the kind of energy-making process that occurs there.

'One approach to male contraception is to disable sperm from swimming, and we think SFEC may be able to play a role in that process,' Herr noted.

Continued at "Male Contraception Discovery"

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Based on the paper:

Compartmentalization of a unique ADP/ATP carrier protein SFEC (Sperm Flagellar Energy Carrier, AAC4) with glycolytic enzymes in the fibrous sheath of the human sperm flagellar principal piece

Young-Hwan Kim, Gerhard Haidl, Martina Schaefer, Ursula Egner and John C. Herr

Abstract

The longest part of the sperm flagellum, the principal piece, contains the fibrous sheath, a cytoskeletal element unique to spermiogenesis. We performed mass spectrometry proteomics on isolated human fibrous sheaths identifying a unique ADP/ATP carrier protein, SFEC [AAC4], seven glycolytic enzymes previously unreported in the human sperm fibrous sheath, and sorbitol dehydrogenase. SFEC, pyruvate kinase and aldolase were co-localized by immunofluorescence to the principal piece. A homology model constructed for SFEC predicted unique residues at the entrance to the nucleotide binding pocket of SFEC that are absent in other human ADP/ATP carriers, suggesting opportunities for selective drug targeting. This study provides the first evidence of a role for an ADP/ATP carrier family member in glycolysis. The co-localization of SFEC and glycolytic enzymes in the fibrous sheath supports a growing literature that the principal piece of the flagellum is capable of generating and regulating ATP independently from mitochondrial oxidation in the mid-piece. A model is proposed that the fibrous sheath represents a highly ordered complex, analogous to the electron transport chain, in which adjacent enzymes in the glycolytic pathway are assembled to permit efficient flux of energy substrates and products with SFEC serving to mediate energy generating and energy consuming processes in the distal flagellum, possibly as a nucleotide shuttle between flagellar glycolysis, protein phosphorylation and mechanisms of motility.

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*Info on John Herr's research interests:

Our laboratory is focused on the structural characterization of sperm proteins and their encoding genes. Two fundamental concepts underlie this work. First, during spermatogenesis, the expression of genes unique to the spermatogenic lineage, results in sperm-specific polypeptides being incorporated into the sperm's cyto architecture. Such testis-specific genes provide good models for understanding the regulation of gene expression during the differentiation of spermatids into mature sperm. Second, the sequestration of sperm from the immune system by the blood-testis barrier allows for many sperm antigens to be recognized immunologically as autoantigens. (More)

Technorati: study, developmental, biology, discovery, new, protein, sperm, male, contraceptive, drugs, contraceptives, flagellar, energy, carrier, sfec, cells, contraception, human, genes, immune, system, proteins, john, herr, evidence

Permanent Link posted by John Latter @ 9:52 AM 0 comments

Stem cells grew, multiplied and differentiated into brain cells on a new three-dimensional scaffold of tiny protein fragments designed to be more like a living body than any other cell culture system.

An MIT engineer and Italian colleagues will report the invention - which may one day replace the ubiquitous Petri dish for growing cells - in the December 27th (2006) issue of the journal PLoS ONE [1]. Shuguang Zhang*, associate director of MIT's Center for Biomedical Engineering, is a pioneer in coaxing tiny fragments of amino acids called self-assembling peptides to organize themselves into useful structures. Working with visiting graduate student Fabrizio Gelain from Milan, Zhang created a designer scaffold from a network of protein nanofibers, each 5,000 times thinner than a human hair and containing pores up to 20,000 times smaller than the eye of a needle.

The researchers were able to grow a healthy colony of adult mouse stem cells on the three-dimensional scaffold without the drawbacks of two-dimensional systems.

In addition to helping researchers get a more accurate picture of how cells grow and behave in the body, the new synthetic structure can provide a more conducive microenvironment for tissue cell cultures and tissues used in regenerative medicine, such as skin grafts or neurons to replace brain cells lost to injury or disease.

The scaffold itself can be transplanted directly into the body with no ill effects.

Continued at "Scientists create 3-D scaffold for growing stem cells"

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[1] Excerpts from:

Designer Self-Assembling Peptide Nanofiber Scaffolds for Adult Mouse Neural Stem Cell 3-Dimensional Cultures

Citation: Gelain F, Bottai D, Vescovi A, Zhang S (2006) Designer Self-Assembling Peptide Nanofiber Scaffolds for Adult Mouse Neural Stem Cell 3-Dimensional Cultures. PLoS ONE 1(1): e119. doi:10.1371/journal.pone.0000119

Abstract

Biomedical researchers have become increasingly aware of the limitations of conventional 2-dimensional tissue cell culture systems, including coated Petri dishes, multi-well plates and slides, to fully address many critical issues in cell biology, cancer biology and neurobiology, such as the 3-D microenvironment, 3-D gradient diffusion, 3-D cell migration and 3-D cell-cell contact interactions. In order to fully understand how cells behave in the 3-D body, it is important to develop a well-controlled 3-D cell culture system where every single ingredient is known. Here we report the development of a 3-D cell culture system using a designer peptide nanofiber scaffold with mouse adult neural stem cells. We attached several functional motifs, including cell adhesion, differentiation and bone marrow homing motifs, to a self-assembling peptide RADA16 (Ac-RADARADARADARADA-COHN2). These functionalized peptides undergo self-assembly into a nanofiber structure similar to Matrigel. During cell culture, the cells were fully embedded in the 3-D environment of the scaffold. Two of the peptide scaffolds containing bone marrow homing motifs significantly enhanced the neural cell survival without extra soluble growth and neurotrophic factors to the routine cell culture media. In these designer scaffolds, the cell populations with beta-Tubulin+, GFAP+ and Nestin+ markers are similar to those found in cell populations cultured on Matrigel. The gene expression profiling array experiments showed selective gene expression, possibly involved in neural stem cell adhesion and differentiation. Because the synthetic peptides are intrinsically pure and a number of desired function cellular motifs are easy to incorporate, these designer peptide nanofiber scaffolds provide a promising controlled 3-D culture system for diverse tissue cells, and are useful as well for general molecular and cell biology.

Introduction

Nearly all tissue cells are embedded in a 3-dimensional (3-D) microenvironment in the body. However, almost all tissue cells have been studied in 2-D Petri dishes, 2-D multi-well plates or 2-D glass slides coated with various substrata. The architecture of the in situ environment of a cell in a living organism is 3-D, where cells are surrounded by other cells as well as many extracellular ligands, including many types of collagens, laminin, and other matrix proteins. The normal three-dimensional environment of cells comprises a complex network of extracellular matrix nanoscale fibers with nanopores that create various local microenvironments. These environments not only allow attachments between cells and the basal membrane, but also allow access to oxygen, hormones and nutrients, as well as removal of waste products.

The movements of cells in the 3-D environment of a living organism typically follow a chemical signal or molecular gradient, which is crucial for organism development. It is known that cells isolated directly from higher organisms frequently alter their metabolism and gene expression patterns in 2-D culture. Cells growing in a 2-D environment may significantly reduce production of particular extracellular matrix proteins and often undergo morphological changes, for instance, an increase in spreading.

Conventional 2-D cell cultures are unlike in vivo systems where cellular communication, transport of oxygen and nutrients, removal of wastes and cellular metabolism take place in a 3-D environment.

Attempts have been made to culture cells in 3-D using synthetic polymers and their copolymers [1]. However, many processed synthetic polymers consist of microfibers approx 10-50 micrometers in diameter, which are similar in size to most cells (approx 5-10 micrometers in diameter). Thus, cells attached to microfibers are still in a two-dimensional environment with a curvature dependent on the diameter of the microfibers. Furthermore, the pores (approx 10-200 micrometers) between the microfibers are often approx 1,000-10,000 times larger than the size of biomolecules, which have sizes just a few nanometers, including small molecular hormones, proteins, growth and other factors, which consequently can quickly diffuse away. For a true 3-D environment, a scaffold's fibers and pores must be substantially smaller than the cells. Although synthetic biopolymer microfiber scaffolds have been studied for over 30 years to mimic in vivo 3D microenvironment, concerns about their degradation products and chemicals involved in their synthesis are still important issues requiring further improvements.

Animal derived biomaterials such as collagen gels, laminin, poly-glycosaminoglycans and materials from basement membranes, including Matrigel have also widely been used in cell cultures [2]-[9]. While they are representative of the correct nanolength scale, they often contain residual growth factors, undefined constituents or non-quantified substances [2]-[6]. This not only makes it difficult to conduct well-controlled studies with these materials, but also poses problems if such scaffolds are ever to be used for growing tissues for human therapies.

An ideal 3-D cell culture system should be fabricated from a synthetic biological material with defined constituents. We previously reported the discovery of a self-assembling peptide system, made from natural amino acids, that can undergo spontaneous assembly into nanofiber scaffolds, approx 10 nm in fiber diameter with pores between 5-200 nm [10]-[12]. These peptides have been chemically produced in large quantity using standard solid phase synthesis method and purified to homogeneity. They have not only been used for the study of cell attachment, survival and proliferation but also to incorporate other motifs [11]-[16], and inject into animals [17]-[19]. These self-assembling peptides form nanofibers that can be controlled at physiological pH by altering salt concentration [10]-[11]. Because the self-assembled nanofibers are several thousand times thinner than synthetic polymer microfibers and cells, thus it is believed that the peptide nanofibers surround cells in a manner similar to the natural extracellular matrix. However a systematic study of different motifs and an examination of how their nanofiber scaffolds interact with cells in details have not been carried out.

Here we report the use of designer peptide nanofiber scaffolds to produce 3-D cultures for the study of mouse adult neural stem cells. We synthesized 18 different peptides that directly incorporate various functional motifs with the self-assembling peptide RADA16. These motifs include sequences shown to promote cell adhesion, differentiation and bone marrow homing activities. These functionalized peptides self-assemble into nanofiber scaffolds where cells can be fully embedded by the scaffold in 3-D. Without addition of soluble growth factors and neurotrophic factors, two of these scaffolds functionalized with bone marrow homing motifs [20] not only significantly enhanced survival of the neural stem cells, but also promoted differentiation towards cells expressing neuronal and glial markers. This is the first example suggesting that designer peptide scaffolds alone without additional extra growth factors could influence neural stem cell differentiation towards neural and glial phenotypes.

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*Shuguang Zhang "...discovered a self-assembling peptide system while working in molecular and structural biology with Alexander Rich at MIT. This serendipitous discovery was selected to be one of the fifteen research achievements over last quart century at MIT. He pursues actively on the various self-assembling peptide systems to develop a new class of biological materials including peptide matrix scaffold for tissue engineering, biological surface engineering for cell pattern formation, molecular switch, biological operating systems and surfactant peptide nanotubes. He also works on problems to gain understanding of a class of protein conformational diseases, including Alzheimer's, Parkinson's and the prion diseases (mad cow disease)..."

Technorati: stem, cells, brain, protein, mit, mouse, 3-d, 2-d, scaffold, adult, culture, system, cell, peptides, proteins, oxygen, hormones, nutrients, designer, alzeimer, parkinson, prion, mad cow, disease

Permanent Link posted by John Latter @ 10:50 AM 0 comments

The 27th research campaign of Bremerhaven's Alfred Wegener Institute for Polar and Marine Research marks the beginning of the summer research season in the Antarctic. The institute collaborates with 20 research institutions and ten logistics organisations from 14 countries. Neumayer Station will serve as the logistical base for extensive measurements using aircraft. An expedition aboard research icebreaker Polarstern is travelling along the Antarctic Peninsula as part of the global 'Census of Marine Life', and at the Dallmann Laboratory activities will be focussing on Antarctic habitats as they undergo climate change. The Antarctic summer lasts from November to April. Many projects will be an overture to the International Polar Year 2007/2008.

Science and Logistics: Neumayer Station
The Alfred Wegener Institute's research station Neumayer (70 degrees 39 minutes S, 08 degrees 15 minutes W) is occupied year round and represents the centre of German Antarctic research. During the current season, a total of 42 scientific and technical staff will be working at the station. Personnel and cargo are being air-freighted and coordinated jointly within DROMLAN (Dronning Maud Land Air Network), an international network of eleven research institutes. In mid December, the new over-wintering crew of the Alfred Wegener Institute arrived at Neumayer Station. This year, the group consists of four women and five men who will be responsible for station maintenance and ongoing long-term collection of meteorological, geophysical and air chemistry data.

Census of Antarctic Marine Life (CAML)
As part of the global research project 'Census of Marine Life' (CoML), an expedition aboard the research icebreaker Polarstern is currently investigating an oceanic region alongside the Antarctic Peninsula which, for the first time, has become accessible to science after a large section of the Larsen B Ice Shelf collapsed in 2002. Within the project, a total of 47 scientists from twelve countries explore biological diversity. The 'Census of Antarctic Marine Life' is the largest marine research programme in the Antarctic and hence represents one of the major IPY projects. Actual videos, pictures and reports from the Polarstern expedition under: www.cousteau.org/caml/html, www.educapoles.org, www.sciencepoles.org, www.polarjahr.de

Aerosols and trace gases
AOn December 15th, the research aircraft Polar 2 landed at Neumayer Station, marking the start of the German-Japanese project ANTSYO II (Japan-German Airborne Observation Program). Until January of 2007, measurements identifying minute airborne particles, so-called aerosols, and various trace gases, will be carried out from the aircraft. The physical, optical and chemical characteristics of aerosols will be the focus of the measurement campaign throughout the Antarctic summer season. In addition, the major pathways of aerosols to the Antarctic will be identified.

Antarctic underwater sounds
For one year now, the working group 'Oceanic Acoustics' of the Alfred Wegener Institute has been maintaining PALAOA, the 'PerenniAL Acoustic Observatory in the Antarctic', located near Neumayer Station. PALAOA (70 degrees 31 minutes S, 8 degrees 13 minutes W), consists of four underwater microphones, so-called hydrophones, which are recording all sounds of the Antarctic Ocean 24 hours a day, seven days a week. Scientists are hoping to gain new insights into communication of marine mammals such as seals and whales. The data will also provide information about the effect of anthropogenic sounds on the behaviour of the animals.
A live audio stream of PALAOA can be found on the internet at: www.awi.de/acoustics

Diverse life in the cold
At the Dallmann Laboratory (62 degrees 14 minutes S, 58 degrees 40 minutes W), only operated during the Antarctic summer, biological research is paramount. In particular, the diversity of various organisms and their adaptations to climate change and extreme environmental conditions are the centre of the researcher's attention. One example is the investigation of algal growth under high light intensities with simultaneous low temperatures by scientists of the Alfred Wegener Institute, in collaboration with the Institute for Polar Ecology in Kiel. The effect of ice movement on species communities of the sea floor is an additional research focus at Dallmann Laboratory. The IPY project CliCOPEN (Impact of Climate induced glacial melting on marine and terrestric COastal communities on a gradient along the Western Antarctic PENinsula) addresses the impact of climate induced glacial melting on coastal species communities of the western Antarctic Peninsula.

Detailed information about all German research projects associated with the 3rd International Polar Year 2007/2008 can be found on the internet at: www.polarjahr.de

The above press release is available via "Antarctic research within the International Polar Year IPY 2007/2008"

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From the International Polar Year website:

"The Polar Regions are remote areas of the Earth that have profound significance for the Earth's climate and ultimately environments, ecosystems and human society. However we still remain remarkably ignorant of many aspects of how polar climate operates and its interaction with polar environments, ecosystems and societies. To have any hope of understanding the current global climate and what might happen in future the science community needs a better picture of conditions at the poles and how they interact with and influence the oceans, atmosphere and land masses. Existing climate models do not work well in the polar regions and have for example failed to predict the dramatic break-up of Antarctic ice shelves observed in recent years. The three fastest warming regions on the planet in the last two decades have been Alaska, Siberia and parts of the Antarctic Peninsula, Thus the Polar Regions are highly sensitive to climate change and this raises real concern for the future of polar ecosystems and Arctic society.

There have been a number of major international science initiatives in Polar Regions since the first International Polar Year in 1882-83 and all have had a major influence in overhauling our understanding of global processes in these important areas. These initiatives have involved an intense period of interdisciplinary research, collecting a broad range of measurements that provide a snapshot in time of the state of the polar regions. The last such initiative was the International Geophysical Year in 1957-58, involving 80,000 scientists from 67 countries."

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From the US IPY website:

A concerted worldwide effort is underway to plan scientific and educational activities for the upcoming International Polar Year (IPY). Scheduled to officially begin in March 2007, IPY promises to advance our understanding of how the Earth's remote polar regions impact global climate systems, to bring about fundamental advances in many areas of science, and to fire the enthusiasm of young men and women for future careers in science and engineering.

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A Press Release from November 13th 2006:

Ice-breaker Polarstern to explore uncharted seafloor

Huge areas of sea floor (around 3,250 square km) have been freed up by the collapse 4 years ago of the Larsen B platform along the Antarctic Peninsula - leaving a blank spot on Antarctic maps. Polarstern, the research flagship of the Alfred Wegener Institute for Polar and Marine Research, will shortly conduct there the first major biological research, studying living communities, from microbes to whales, including bottom fish and squids...

Evolution of bottom Fauna

Meanwhile, the vanishing ice allowing vegetal and animal plankton to reinvade and thrive in these areas offers a perfect opportunity to study the evolution of bottom animal communities depending on this plankton. Sampling with various trawls, grabs and traps and the use of a remote operated vehicle with a video camera will allow the description of new species within this near-pristine environment. A dozen scientific studies will look into groups as different as microbes, sponges, crustaceans, octopuses, starfish and whales, from the grounding line to the open sea areas, and will furthermore give the best benchmark of the early stages of colonization. These studies could become a reference for other parts of Antarctica where such disintegration of ice shelves is already expected on how climate-induced shifts in biodiversity will change in ecosystems structured largely by ice.

Mud Volcanoes

The expedition will also lead the first biological studies of a recently discovered cold-vent ecosystem in the same Larsen area, the first of its kind known in Antarctica. Uncovered in 2005 by an American geoscience research team, this 8 km zone harbors mounds spewing out fluid and mud particles, as well as clusters of large clams. These mollusks and their associated fauna probably depend on chemical energy from the Earth, rather than one driven by photosynthesis from the sun or from hot emissions rising from inside the planet.

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Antarctic webcams (some may need to be manually updated via the browser reload/refresh button) include:

New Zealand's Scott Base webcam

Australia's Mawson Station webcam

Germany's Penguin webcam

Permanent Link posted by John Latter @ 10:29 AM 0 comments

Losing expensive scientific equipment is usually a cause for dismay. But when Maya Tolstoy*** couldn't retrieve eight seismometers from the bottom of the sea this April, the Columbia University geophysicist was thrilled.

The devices, she suspected, had been buried under a lava flow 1.2 miles below the surface of the Pacific Ocean. When scientists at the Woods Hole Oceanographic Institution* (WHOI) confirmed her suspicions a few months later, they also confirmed that her instruments had - for the first time ever - captured an undersea volcano while it erupted.

'We've been trying for decades to get instruments on top of a [deep-sea] eruption as it happens,' said Tolstoy, who published initial data from two recovered seismometers in the December 22 issue of the journal Science. 'We've never recorded this fundamental process on nearby seismic instruments before.'

From the new seismic data and a bevy of new scientific efforts launched at the eruption site, researchers expect to get an unprecedented look at the geological, chemical, and biological processes of deep-sea volcanic zones called mid-ocean ridges**.

Continued at "Volcanoes of the deep" (may require free registration)

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Based on the journal Science paper:

"A Sea-Floor Spreading Event Captured by Seismometers"

by M. Tolstoy et al.

Originally published in Science Express on 23 November 2006
Science 22 December 2006:
Vol. 314. no. 5807, pp. 1920 - 1922
DOI: 10.1126/science.1133950

Abstract

Two-thirds of Earth's surface is formed at mid-ocean ridges, yet sea-floor spreading events are poorly understood because they occur far beneath the ocean surface. At 9 degrees 50 minutes N on the East Pacific Rise, ocean-bottom seismometers recently recorded the microearthquake character of a mid-ocean ridge eruption, including precursory activity. A gradual ramp-up in activity rates since seismic monitoring began at this site in October 2003 suggests that eruptions may be forecast in the fast-spreading environment. The pattern culminates in an intense but brief (approx 6-hour) inferred diking event on 22 January 2006, followed by rapid tapering to markedly decreased levels of seismicity.

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*Excerpt from an earlier (but related) Woods Hole Oceanographic Institution news release ("Scientists "See" New Ocean Floor Just Before and After It Is Created" November 23 2006):

A multidisciplinary research team from six institutions has for the first time successfully measured a seafloor eruption at its source along the global mid-ocean ridge, the most active volcanic system on Earth. The event along the East Pacific Rise has provided researchers from Woods Hole Oceanographic Institution (WHOI) with a rare opportunity to observe what happens in the immediate aftermath of an eruption.

Ocean-bottom seismometers, which had been deployed by researchers from the Lamont-Doherty Earth Observatory (LDEO) of Columbia University, detected steadily increasing levels of earthquake activity over several years leading up to 2006. Research teams from WHOI and other institutions then used towed cameras and the submersible Alvin to make a visual confirmation of the seafloor eruptions, which decimated the well-studied communities of tubeworms, mussels, and other unique organisms that had been living at the hydrothermal vents in the area.

A research paper describing the seismic data was authored by Maya Tolstoy of LDEO and includes scientists from WHOI, the University of Hawaii, Brown University, the University of Washington, the University of Florida, and NOAA' s Pacific Marine Environmental Laboratory (PMEL). The findings will be published in an upcoming issue of Science, though a preliminary analysis was released on 23 November 2006 on the Science Express web site.

"We rarely get to observe a deep-ocean eruption just after the fact," said WHOI geologist Adam Soule, who helped confirm and map the seafloor eruption. "This will add substantially to our understanding of how mid-ocean ridges work."

Through research expeditions in May and June 2006 - as well as another that just departed on 22 November - WHOI researchers have been heavily involved in characterizing the extent of the eruptions and in observing its effects on the communities of unusual species that thrive in the mineral-rich fluids that spew from hydrothermal vents on mid-ocean ridges. More than two-thirds of Earth' s crust is created along seafloor spreading ridges, yet scientists rarely have a chance to observe the process is action.

In 2003, the LDEO team deployed a dozen seismometers on the ocean floor along the East Pacific Rise (EPR), near 9 degrees 50 minutes N latitude, about 400 miles south of Acapulco, Mexico. Each year when they returned to service the instruments, the researchers detected steadily increasing levels of earthquake activity as magma moved beneath the ridge axis. They suspected a major seismic event was imminent. Sometime between May 2005 (the last readout of the seismometers) and April 2006, a series of volcanic eruptions paved over areas of the ocean floor.

A scheduled expedition on the WHOI-operated Research Vessel (R/V) Knorr in April 2006 provided the first hint of an eruption. The LDEO team discovered that most of their instruments could not be recovered and surmised that a seafloor eruption had probably wiped them out.

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**Info on mid-ocean ridges from the New Millenium Observatory (NeMo):

The global mid-ocean ridge system is the largest single volcanic feature on the Earth, encircling it like the seams of a baseball. Here the Earth’s crust is spreading, creating new ocean floor and literally renewing the surface of our planet. Older crust is recycled back into the mantle elsewhere on the globe, typically where plates collide. The mid-ocean ridge consists of thousands of individual volcanoes or volcanic ridge segments which periodically erupt.

Beneath a typical mid-ocean ridge, mantle material partially melts as it rises in response to reduced pressure. This melted rock, or "magma", may collect in a reservoir a few kilometers below the seafloor, awaiting eruption. Much of the magma eventually freezes in place there within the crust, forming the bulk of the new oceanic crust without erupting at all. Average oceanic crust is about 10km thick, but only the upper 1 to 3 km are formed by eruption processes. [seismometer]

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***A May 2002 interview with Mara Tolkstoy from Dive and Discover:

...I received my undergraduate degree from the University of Edinburgh in geophysics in 1988. I spent the summer of 1987 at Scripps Institution of Oceanography as an undergraduate research fellow, and found I enjoyed research, and loved going to sea. After I graduated, I wanted to move back to the US and also wanted to travel. I figured that graduate work in marine geophysics would let me continue to do research in an area I liked, and would also give me opportunities to travel and go to sea. I was accepted at Scripps, and while I was there I went on 16 cruises in various parts of the Atlantic and Pacific Oceans. I specialized in marine seismology, and worked with both seismic data and seafloor instrumentation...

Technorati: seismometer, maya, tolstoy, lava, flow, pacific, ocean, whoi, undersea, volcano, deep-sea, eruption, science, mid, ridges, floor, ridge, alvin, submersible, nemo, volcanoes, magma, research, seismology

Permanent Link posted by John Latter @ 1:07 PM 0 comments

[February 22, 2007: "Colossal Squid caught in the Ross Sea, Antartica" - see below]

[February 15, 2007: "Hunting behavior of Large Bioluminescent Squid (Video)"]

Original post and video follows:

Tokyo (AP) - A Japanese research team has succeeded in filming a giant squid* live - possibly for the first time - and says the elusive creatures may be more plentiful than previously believed, a researcher said Friday.

[On rare occasions this error occurs: "Dear user, we are experiencing tremendously heavy levels of traffic today (in excess of 100,000 unique visitors per hour) which has resulted in this error. Please hit refresh in your browser or try again shortly."]

The research team, led by Tsunemi Kubodera, videotaped the giant squid at the surface as they captured it off the Ogasawara Islands south of Tokyo earlier this month. The squid, which measured about 24-feet long, died while it was being caught.

"We believe this is the first time anyone has successfully filmed a giant squid that was alive," said Kubodera, a researcher with Japan's National Science Museum. "Now that we know where to find them, we think we can be more successful at studying them in the future."

Continued at "Japan Researchers Film Live Giant Squid" [Video]

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An earlier BBC News report from 25 Sptember:

Live giant squid caught on camera

A live, adult giant squid has been caught on camera in the wild for the very first time.

Japanese researchers took pictures of the elusive creature hunting 900m down, enveloping its prey by coiling its tentacles into a ball.

The images show giant squid, known as Architeuthis, are more vigorous hunters than has been supposed.

The images, captured in the Pacific Ocean, appear in the journal Proceedings of the Royal Society B.

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Related Technical Papers:

1) First-ever observations of a live giant squid in the wild
By Kubodera T and Mori K.

Proc Biol Sci. 2005 Dec 22;272(1581):2583-6
doi:10.1098/rspb.2005.3158

Abstract

The giant squid, Architeuthis, is renowned as the largest invertebrate in the world and has featured as an ominous sea monster in novels and movies. Considerable efforts to view this elusive creature in its deep-sea habitat have been singularly unsuccessful. Our digital camera and depth recorder system recently photographed an Architeuthis attacking bait at 900m off Ogasawara Islands in the North Pacific. Here, we show the first wild images of a giant squid in its natural environment. Recovery of a severed tentacle confirmed both identification and scale of the squid (greater than 8m). Architeuthis appears to be a much more active predator than previously suspected, using its elongate feeding tentacles to strike and tangle prey.

2) Anatomical basis for camouflaged polarized light communication in squid

Lydia M. Mathger and Roger T. Hanlon

Biology Letters
ISSN: 1744-9561 (Paper) 1744-957X (Online)
Issue: Volume 2, Number 4 / December 22, 2006
Pages: 494 - 496
DOI: 10.1098/rsbl.2006.0542

Abstract

Camouflage is a means to defeat visual detection by predators, whereas visual communication involves a signal that is conspicuous to a receiver (usually a conspecific). However, most intraspecific visual signals are also conspicuous to predators, so that signalling can lead to the serious consequence of predation. Could an animal achieve visual camouflage and simultaneously send a hidden visual message to a conspecific? Here, we present evidence that the polarized aspect of iridescent colour in squid skin is maintained after it passes through the overlying pigmented chromatophores, which produce the highly evolved - and dynamically changeable - camouflaged patterns in cephalopods. Since cephalopods are polarization sensitive, and can regulate polarization via skin iridescence, it is conceivable that they could send polarized signals to conspecifics while staying camouflaged to fish or mammalian predators, most of which are not polarization sensitive.

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*Info on Giant Squid:

Giant squid, once believed to be mythical creatures, are squid of the Architeuthidae family, represented by as many as eight species of the genus Architeuthis. They are deep-ocean dwelling animals that can grow to a tremendous size: recent estimates put the maximum size at 10 meters (34 ft) for males and 13 meters (44 ft) for females from caudal fin to the tip of the two long tentacles (second only to the Colossal Squid at an estimated 14 meters (46 ft), one of the largest living organisms). The mantle length is only about 2 meters (7 ft) in length (more for females, less for males), and the length of the squid excluding its tentacles is about 5 meters (16 ft). In the past there were reported claims of specimens of up to 20 meters (66 ft), but no animals of such size have been scientifically documented. On September 30, 2004, researchers from the National Science Museum of Japan and the Ogasawara Whale Watching Association took the first images of a live giant squid in its natural habitat.[1] Several of the 556 photos were released a year later.

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Colossal Squid caught in the Ross Sea, Antartica

February 22, 2007: "New Zealand fishermen have caught what is expected to be a world-record-breaking colossal squid...

..Jim Anderton of New Zealand's Ministry of Fisheries said the squid, weighing an estimated 450kg (990lb),took two hours to land in Antarctic waters.

Local news said the Mesonychoteuthis hamiltoni was about 10m (33ft) long, and was the first adult colossal squid landed intact.

"I can assure you that this is going to draw phenomenal interest. It is truly amazing," Steve O'Shea from Auckland's University of Technology told local media." [From the BBC UK News Report "NZ fishermen land colossal squid" (adapted)]

If the estimated weight is correct, this colossal squid with "eyes as big as dinner plates" would be about 330 pounds heavier than the next biggest specimen ever found. It was caught by fishermen from the longliner ship San Aspiring (owned by the Sanford Seafood Company) while they were catching Patagonian toothfish (sold under the name Chilean sea bass) in the Ross Sea, Antartica - the date of the catch has not yet been disclosed.

Technorati: japanese, research, team, giant, squid, video, japan, national, science, museum, pacific, ocean, camouflage, colossal

Permanent Link posted by John Latter @ 3:12 PM 0 comments

An open access/free article from the Proceedings of the National Academy of Sciences (PNAS):

Global mammal distributions, biodiversity hotspots, and conservation

by Gerardo Ceballos (homepage) and Paul R. Ehrlich*

Abstract and Introduction

Hotspots, which have played a central role in the selection of sites for reserves, require careful rethinking. We carried out a global examination of distributions of all nonmarine mammals to determine patterns of species richness, endemism, and endangerment, and to evaluate the degree of congruence among hotspots of these three measures of diversity in mammals. We then compare congruence of hotspots in two animal groups (mammals and birds) to assess the generality of these patterns. We defined hotspots as the richest 2.5% of cells in a global equal-area grid comparable to 1 degree latitude x 1 degree longitude. Hotspots of species richness, "endemism," and extinction threat were noncongruent. Only 1% of cells and 16% of species were common to the three types of mammalian hotspots. Congruence increased with increases in both the geographic scope of the analysis and the percentage of cells defined as being hotspots. The within-mammal hotspot noncongruence was similar to the pattern recently found for birds. Thus, assigning global conservation priorities based on hotspots is at best a limited strategy.

Few topics in conservation biology have received as much attention as hotspots of species diversity. Hotspots have been widely used to determine priority areas for conservation at different geographic scales, and in recommending concentrating resources in those regions to maximize the number of protected species (1, 2). Hotspots are defined as either the top sites in terms of species diversity or as the most threatened and most diverse sites (1, 3, 4). In these definitions, identifying hotspots requires a measure of species diversity, which often is species richness, number of restricted-range (e.g., endemic) species, or number of species at risk, and a measure of threat, which often is human population density or land converted to agriculture (5, 6). A critical assumption of the use of hotspots for conservation that has not been widely tested at a global level is how much congruence or overlap there is among hotspots of species richness, endemic species, or species at risk. Wide overlap among these three types of hotspots implies the selection of fewer sites to represent all species and the possibility of using one of them as a surrogate for the others.

In this paper we assessed the distribution of 4,818 nonmarine mammal species (excluding cetaceans, sirenians, and pinnipeds; list available from G.C. on request) to make a general evaluation of the utility of hotspots for determining conservation priorities for the mammals of the World. Global patterns of species distribution were assessed by comparing the distribution of all mammal species in 17,800 equal-area terrestrial cells of 100 x 100 km (5, 7). Using this database, we evaluated (i) mammalian species richness, endemism (hereafter, more accurately, restricted–range species or "narrow-ranging" species (8), and threatened species: (ii) hotspots for those three aspects of mammal diversity, defined as the top 2.5% of cells in each category: (iii) congruence among the three kinds of hotspots and comparisons with published data on bird hotspots; (iv) sensitivity of results to hotspot definitions (i.e., geographic area covered by the hotspot and the percentage of cells considered as hotspot cells); and (v) efficiency of hotspots for conservation of mammalian species diversity.

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*Info on Paul Ehrlich:

...Dr. Ehrlich's main area of research is Population Biology, which includes ecology, evolutionary biology, behavior, and human ecology. Ehrlich has carried out field, laboratory, and theoretical research on a wide array of problems ranging from the dynamics and genetics of insect populations, studies of the ecological and evolutionary interactions of plants and herbivores, and the behavioral ecology of birds and reef fishes, to experimental studies of the effects of crowding on human beings. His fieldwork has carried him to all continents, from the arctic and the antarctic to the tropics, and from high mountains to the ocean floor. He collaborates with colleagues in biology and in the disciplines of economics, psychology, political science, and the law, in policy research on human ecology...

Technorati: biodiversity, hotspots, conservation, mammals, species, birds, extinction, global, diversity, agriculture, evolutionary, biology, genetics, ecology, psychology, human, science

Permanent Link posted by John Latter @ 9:34 AM 0 comments