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Photos Reveal Myanmar’s Large And Small Predators:

Using remote camera traps to lift the veil on Myanmar’s dense northern wild lands, researchers from the Wildlife Conservation Society have painstakingly gathered a bank of valuable data on the country’s populations of tigers and other smaller, lesser known carnivores (see photo attachments). These findings will help in the formulation of conservation strategies for the country’s wildlife.

Erectile Dysfunction Related To Sleep Apnea May Persist, But Is Treatable:

For sufferers of sleep apnea, erectile dysfunction (ED) is often part of the package. New research indicates that ED in cases of obstructive sleep apnea syndrome (OSAS) may be linked to the chronic intermittent hypoxia–oxygen deprivation– (CIH) that patients with OSAS experience during episodes of obstructed breathing.

Infidelity Dissected: New Research On Why People Cheat:

The probability of someone cheating during the course of a relationship varies between 40 and 76 percent. “It’s very high,” says Geneviève Beaulieu-Pelletier, PhD student at the Université de Montréal’s Department of Psychology. “These numbers indicate that even if we get married with the best of intentions things don’t always turn out the way we plan. What interests me about infidelity is why people are willing to conduct themselves in ways that could be very damaging to them and to their relationship.”

How Not To Gain The Dreaded ‘Freshman Fifteen’:

When fall classes at the University of California, San Diego begin on Sept. 25, freshmen will be on their own for the first time to spend endless hours on the computer, play video games and eat whatever they want, a recipe for weight gain. However, several UC San Diego wellness, weight-management and counseling programs will help students beat the dreaded “freshmen fifteen.”

New Cannabis-like Drugs Could Block Pain Without Affecting Brain, Says Study:

A new type of drug could alleviate pain in a similar way to cannabis without affecting the brain, according to a new study.

Photo Reveals Rare Okapi Survived Poaching Onslaught:

A set of stripy legs in a camera trap photo snapped in an African forest indicates something to cheer about, say researchers from the Wildlife Conservation Society. The legs belong to an okapi–a rare forest giraffe–which apparently has survived in the Democratic Republic of Congo’s Virunga National Park, despite over a decade of civil war and increased poaching.

Faster, Cheaper Way Of Analyzing The Human Genome Developed:

Investigators at the Translational Genomics Research Institute (TGen) has recently announced a faster and less expensive way for scientists to find which genes might affect human health.

Male-specific Neurons Directly Linked To Gender-specific Behaviors:

New research identifies a few critical neurons that initiate sex-specific behaviors in fruit flies and, when masculinized, can elicit male-typical courtship behaviors from females. The study, published by Cell Press in the September 11th issue of the journal Neuron, demonstrates a direct link between sexual dimorphism in the brain and gender differences in behavior.

My, What Big Teeth You Had! Extinct Species Had Huge Teeth On Roof Of Mouth:

When the world’s land was congealed in one supercontinent 240 million years ago, Antarctica wasn’t the forbiddingly icy place it is now. But paleontologists have found a previously unknown amphibious predator species that probably still made it less than hospitable. The species, named Kryostega collinsoni, is a temnospondyl, a prehistoric amphibian distantly related to modern salamanders and frogs. K. collinsoni resembled a modern crocodile, and probably was about 15 feet in length with a long and wide skull even flatter than a crocodile’s.

Computational Biochemist Uncovers A Molecular Clue To Evolution:

A Florida State University researcher who uses high-powered computers to map the workings of proteins has uncovered a mechanism that gives scientists a better understanding of how evolution occurs at the molecular level.

Math Model Helps Unravel Relationship Between Nutrients And Biodiversity:

The level of nutrients in soil determines how many different kinds of plants and trees can thrive in an ecosystem, according to new research published by biologists and mathematicians in Nature.

Teens’ Failure To Use Condoms Linked To Partner Disapproval, Fear Of Less Sexual Pleasure:

Approximately one in four teens in the United States will contract a sexually transmitted disease (STD), according to the Centers for Disease Control and Prevention. Experts believe a major contributing factor is the failure of many teens to use condoms consistently and routinely. Now a new study provides some insight into some of the factors that influence condom use among teenagers.

Psychiatry: When The Mirror Becomes An Enemy:

A nose that’s too big, hair that’s too curly or a beauty mark in the wrong place – who hasn’t focused on a small detail of their appearance while staring at a mirror? But when these imperfections take over our thoughts, or exist only in our heads, it’s a sign that such obsessing is a disorder, according to Université de Montréal psychiatry professor Kieron O’Connor.

Brains Rely On Old And New Mechanisms To Diminish Fear:

Humans have developed complex thought processes that can help to regulate their emotions, but these processes are also linked with evolutionarily older mechanisms that are common across species, according to a study by neuroscientists at New York and Rutgers universities. The research appears in the Sept. 11 issue of the journal Neuron.

Searching In Space And Minds: Research Suggests Underlying Link:

New research from Indiana University has found evidence that how we look for things, such as our car keys or umbrella, could be related to how we search for more abstract needs, such as words in memory or solutions to problems.

Air Pollution Can Hinder Heart’s Electrical Functioning:

Microscopic particles in polluted air can adversely affect the heart’s ability to conduct electrical signals in people with serious coronary artery disease, researchers reported in Circulation: Journal of the American Heart Association.

Oldest Sheep Contribute Most To Population Growth When Climate Changes Making Conditions Harsh:

Populations of wild animals face the challenge of surviving in a changing climate. Researchers at Imperial College London and Université Claude Bernard Lyon have shown how a sheep population on a remote island off the west coast of Scotland responds to two consequences of climate change: altered food availability and the unpredictability of winter storms.

DNA ‘Tattoos’ Link Adult, Daughter Stem Cells In Planarians:

Unlike some parents, adult stem cells don’t seem to mind when their daughters get a tattoo. In fact, they’re willing to pass them along.

Color-coded Bacteria Can Spot Oil Spills Or Leaky Pipes And Storage Tanks:

Oil spills and other environmental pollution, including low level leaks from underground pipes and storage tanks, could be quickly and easily spotted in the future using colour coded bacteria, scientists heard at the Society for General Microbiology’s Autumn meeting being held this week at Trinity College, Dublin.

Mad Cow Disease Also Caused By Genetic Mutation:

New findings about the causes of mad cow disease show that sometimes it may be genetic. “We now know it’s also in the genes of cattle,” said Juergen A. Richt, Regents Distinguished Professor of Diagnostic Medicine and Pathobiology at Kansas State University’s College of Veterinary Medicine.

There are 10 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. Here are my own picks for the week – you go and look for your own favourites:
Circadian Control of the Daily Plasma Glucose Rhythm: An Interplay of GABA and Glutamate:

The mammalian biological clock, located in the hypothalamic suprachiasmatic nuclei (SCN), imposes its temporal structure on the organism via neural and endocrine outputs. To further investigate SCN control of the autonomic nervous system we focused in the present study on the daily rhythm in plasma glucose concentrations. The hypothalamic paraventricular nucleus (PVN) is an important target area of biological clock output and harbors the pre-autonomic neurons that control peripheral sympathetic and parasympathetic activity. Using local administration of GABA and glutamate receptor (ant)agonists in the PVN at different times of the light/dark-cycle we investigated whether daily changes in the activity of autonomic nervous system contribute to the control of plasma glucose and plasma insulin concentrations. Activation of neuronal activity in the PVN of non-feeding animals, either by administering a glutamatergic agonist or a GABAergic antagonist, induced hyperglycemia. The effect of the GABA-antagonist was time dependent, causing increased plasma glucose concentrations only when administered during the light period. The absence of a hyperglycemic effect of the GABA-antagonist in SCN-ablated animals provided further evidence for a daily change in GABAergic input from the SCN to the PVN. On the other hand, feeding-induced plasma glucose and insulin responses were suppressed by inhibition of PVN neuronal activity only during the dark period. These results indicate that the pre-autonomic neurons in the PVN are controlled by an interplay of inhibitory and excitatory inputs. Liver-dedicated sympathetic pre-autonomic neurons (responsible for hepatic glucose production) and pancreas-dedicated pre-autonomic parasympathetic neurons (responsible for insulin release) are controlled by inhibitory GABAergic contacts that are mainly active during the light period. Both sympathetic and parasympathetic pre-autonomic PVN neurons also receive excitatory inputs, either from the biological clock (sympathetic pre-autonomic neurons) or from non-clock areas (para-sympathetic pre-autonomic neurons), but the timing information is mainly provided by the GABAergic outputs of the biological clock.

Transcriptional Autoregulatory Loops Are Highly Conserved in Vertebrate Evolution:

Feedback loops are the simplest building blocks of transcriptional regulatory networks and therefore their behavior in the course of evolution is of prime interest. We address the question of enrichment of the number of autoregulatory feedback loops in higher organisms. First, based on predicted autoregulatory binding sites we count the number of autoregulatory loops. We compare it to estimates obtained either by assuming that each (conserved) gene has the same chance to be a target of a given factor or by assuming that each conserved sequence position has an equal chance to be a binding site of the factor. We demonstrate that the numbers of putative autoregulatory loops conserved between human and fugu, danio or chicken are significantly higher than expected. Moreover we show, that conserved autoregulatory binding sites cluster close to the factors’ starts of transcription. We conclude, that transcriptional autoregulatory feedback loops constitute a core transcriptional network motif and their conservation has been maintained in higher vertebrate organism evolution.

In Vitro Cellular Adaptations of Indicators of Longevity in Response to Treatment with Serum Collected from Humans on Calorie Restricted Diets:

Calorie restriction (CR) produces several health benefits and increases lifespan in many species. Studies suggest that alternate-day fasting (ADF) and exercise can also provide these benefits. Whether CR results in lifespan extension in humans is not known and a direct investigation is not feasible. However, phenotypes observed in CR animals when compared to ad libitum fed (AL) animals, including increased stress resistance and changes in protein expression, can be simulated in cells cultured with media supplemented with blood serum from CR and AL animals. Two pilot studies were undertaken to examine the effects of ADF and CR on indicators of health and longevity in humans. In this study, we used sera collected from those studies to culture human hepatoma cells and assessed the effects on growth, stress resistance and gene expression. Cells cultured in serum collected at the end of the dieting period were compared to cells cultured in serum collected at baseline (before the dieting period). Cells cultured in serum from ADF participants, showed a 20% increase in Sirt1 protein which correlated with reduced triglyceride levels. ADF serum also induced a 9% decrease in proliferation and a 25% increase in heat resistance. Cells cultured in serum from CR participants induced an increase in Sirt1 protein levels by 17% and a 30% increase in PGC-1α mRNA levels. This first in vitro study utilizing human serum to examine effects on markers of health and longevity in cultured cells resulted in increased stress resistance and an up-regulation of genes proposed to be indicators of increased longevity. The use of this in vitro technique may be helpful for predicting the potential of CR, ADF and other dietary manipulations to affect markers of longevity in humans.

Reproductive Flexibility: Genetic Variation, Genetic Costs and Long-Term Evolution in a Collembola:

In a variable yet predictable world, organisms may use environmental cues to make adaptive adjustments to their phenotype. Such phenotypic flexibility is expected commonly to evolve in life history traits, which are closely tied to Darwinian fitness. Yet adaptive life history flexibility remains poorly documented. Here we introduce the collembolan Folsomia candida, a soil-dweller, parthenogenetic (all-female) microarthropod, as a model organism to study the phenotypic expression, genetic variation, fitness consequences and long-term evolution of life history flexibility. We demonstrate that collembola have a remarkable adaptive ability for adjusting their reproductive phenotype: when transferred from harsh to good conditions (in terms of food ration and crowding), a mother can fine-tune the number and the size of her eggs from one clutch to the next. The comparative analysis of eleven clonal populations of worldwide origins reveals (i) genetic variation in mean egg size under both good and bad conditions; (ii) no genetic variation in egg size flexibility, consistent with convergent evolution to a common physiological limit; (iii) genetic variation of both mean reproductive investment and reproductive investment flexibility, associated with a reversal of the genetic correlation between egg size and clutch size between environmental conditions ; (iv) a negative genetic correlation between reproductive investment flexibility and adult lifespan. Phylogenetic reconstruction shows that two life history strategies, called HIFLEX and LOFLEX, evolved early in evolutionary history. HIFLEX includes six of our 11 clones, and is characterized by large mean egg size and reproductive investment, high reproductive investment flexibility, and low adult survival. LOFLEX (the other five clones) has small mean egg size and low reproductive investment, low reproductive investment flexibility, and high adult survival. The divergence of HIFLEX and LOFLEX could represent different adaptations to environments differing in mean quality and variability, or indicate that a genetic polymorphism of reproductive investment reaction norms has evolved under a physiological tradeoff between reproductive investment flexibility and adult lifespan.

Female Spiders Eat Small Males When They Mate:

Female spiders are voracious predators and consume a wide range of prey, which sometimes includes their mates. A number of hypotheses have been proposed for why females eat males before or after mating. Researchers Shawn Wilder and Ann Rypstra from Miami University in Ohio found that the answer may be simpler than previously thought. Males are more likely to be eaten if they are much smaller than females, which likely affects how easy they are to catch.

Cryopreservation Techniques Bring Hopes For Women Cancer Victims And Endangered Species:

Emerging cryopreservation techniques are increasing hope of restoring fertility for women after diseases such as ovarian cancer that lead to destruction of reproductive tissue. The same techniques can also be used to maintain stocks of farm animals, and protect against extinction of endangered animal species by maintaining banks of ovarian tissue or even nascent embryos that can be used to produce offspring at some point in the future.

Real-world Behavior And Biases Show Up In Virtual World:

Americans are spending increasing amounts of time hanging around virtual worlds in the forms of cartoon-like avatars that change appearances according to users’ wills, fly through floating cities in the clouds and teleport instantly to glowing crystal canyons and starlit desert landscapes.

Good Luck, Not Superiority, Gave Dinosaurs Their Edge, Study Of Crocodile Cousins Reveals:

In a paper published in Science, Steve Brusatte and Professor Mike Benton challenge the general consensus among scientists that there must have been something special about dinosaurs that helped them rise to prominence.

Flies, Too, Feel The Influence Of Their Peers, Studies Find:

We all know that people can be influenced in complex ways by their peers. But two new studies in the September 11th issue of Current Biology, a Cell Press publication, reveal that the same can also be said of fruit flies. The researchers found that group composition affects individual flies in several ways, including changes in gene activity and sexual behavior, all mediated by chemical communication.

So, let’s see what’s new in PLoS Genetics, PLoS Computational Biology, PLoS Pathogens and PLoS Neglected Tropical Diseases this week. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. Here are my own picks for the week – you go and look for your own favourites:
Is Mate Choice in Humans MHC-Dependent?:

There has been a longstanding hypothesis that selection may have led to mating patterns that encourage heterozygosity at Major Histocompatibility Complex (MHC) loci because of improved immune response to pathogens in the offspring of such matings, and, indeed, this has been observed in several model systems. However, in humans, previous studies regarding the role of the MHC in mate choice or preference, both directly in couples and also indirectly in “sweaty T-shirts” experiments, have reported conflicting results. Here, by using genome-wide genotype data and HLA types in African and European American couples, we test whether humans tend to choose MHC-dissimilar mates. This approach allows us to distinguish MHC-specific effects from genome-wide effects. In the African sample, the patterns at MHC loci is confounded by genome-wide effects, possibly resulting from demographic processes relating to the social organization of this population, and no tendency to choose MHC-dissimilar mates is detected. On the other hand, the sampled European Americans appear to have favoured MHC-dissimilar mates, supporting the hypothesis that MHC influences mate choice in some human populations. Thus, this study suggests that, in some cases, humans may rely on biological factors, in addition to social factors, when choosing a mate.

Evolution of a New Function by Degenerative Mutation in Cephalochordate Steroid Receptors:

Most genes evolved by duplication of more ancient genes. Under existing models of this process, mutations that compromise one copy have no effect on the other; as long as one copy remains intact, such “degenerative” mutations are shielded from selection. Because degenerative mutations are common, most duplicates are expected to be disabled before new functions can evolve. The great functional diversity of genes is therefore somewhat puzzling. Here, we reconstruct how simple degenerative mutations produced a new function in the steroid hormone receptors (SRs), a gene family crucial to reproduction and development. We characterized the two SRs of B. floridae, a cephalochordate that diverged from vertebrates ~500 million years ago, just after the ancestral SR duplicated. One retained the ancestral gene’s estrogen receptor-like functions, while the other evolved a new function as a competitive repressor of the first. Either of two historical mutations is sufficient to recapitulate evolution of this function by disabling the receptor’s response to estrogen, but leaving its DNA-binding capacity intact. Our results suggest that, for the many genes that function by specifically interacting with other molecules, simple mutations can yield novel functions that, beneficial or deleterious, are exposed to selection.

Sizing Up Allometric Scaling Theory:

The rate at which an organism produces energy to live increases with body mass to the 3/4 power. Ten years ago West, Brown, and Enquist posited that this empirical relationship arises from the structure and dynamics of resource distribution networks such as the cardiovascular system. Using assumptions that capture physical and biological constraints, they defined a vascular network model that predicts a 3/4 scaling exponent. In our paper we clarify that this model generates the 3/4 exponent only in the limit of infinitely large organisms. Our calculations indicate that in the finite-size version of the model metabolic rate and body mass are not related by a pure power law, which we show is consistent with available data. We also show that this causes the model to produce scaling exponents significantly larger than the observed 3/4. We investigate how changes in certain assumptions about network structure affect the scaling exponent, leading us to identify discrepancies between available data and the predictions of the finite-size model. This suggests that the model, the data, or both, need reassessment. The challenge lies in pinpointing the physiological and evolutionary factors that constrain the shape of networks driving metabolic scaling.

Top-Down Analysis of Temporal Hierarchy in Biochemical Reaction Networks:

Cellular metabolism describes the complex web of biochemical transformations that are necessary to build the structural components, to convert nutrients into “usable energy” by the cell, and to degrade or excrete the by-products. A critical aspect toward understanding metabolism is the set of dynamic interactions between metabolites, some of which occur very quickly while others occur more slowly. To develop a “systems” understanding of how networks operate dynamically we need to identify the different processes that occur on different time scales. When one moves from very fast time scales to slower ones, certain components in the network move in concert and pool together. We develop a method to elucidate the time scale hierarchy of a network and to simplify its structure by identifying these pools. This is applied to dynamic models of metabolism for the human red blood cell, human folate metabolism, and yeast glycolysis. It was possible to simplify the structure of these networks into biologically meaningful groups of variables. Because dynamics play important roles in normal and abnormal function in biology, it is expected that this work will contribute to an area of great relevance for human disease and engineering applications.

There are 11 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. Here are my own picks for the week – you go and look for your own favourites:
Practice Makes Imperfect: Restorative Effects of Sleep on Motor Learning:

Emerging evidence suggests that sleep plays a key role in procedural learning, particularly in the continued development of motor skill learning following initial acquisition. We argue that a detailed examination of the time course of performance across sleep on the finger-tapping task, established as the paradigm for studying the effect of sleep on motor learning, will help distinguish a restorative role of sleep in motor skill learning from a proactive one. Healthy subjects rehearsed for 12 trials and, following a night of sleep, were tested. Early training rapidly improved speed as well as accuracy on pre-sleep training. Additional rehearsal caused a marked slow-down in further improvement or partial reversal in performance to observed levels below theoretical upper limits derived on the basis of early pre-sleep rehearsal. This decrement in learning efficacy does not occur always, but if and only if it does, overnight sleep has an effect in fully or partly restoring the efficacy and actual performance to the optimal theoretically achieveable level. Our findings re-interpret the sleep-dependent memory enhancement in motor learning reported in the literature as a restoration of fatigued circuitry specialized for the skill. In providing restitution to the fatigued brain, sleep eliminates the rehearsal-induced synaptic fatigue of the circuitry specialized for the task and restores the benefit of early pre-sleep rehearsal. The present findings lend support to the notion that latent sleep-dependent enhancement of performance is a behavioral expression of the brain’s restitution in sleep.

Systematic Variation in Reviewer Practice According to Country and Gender in the Field of Ecology and Evolution:

The characteristics of referees and the potential subsequent effects on the peer-review process are an important consideration for science since the integrity of the system depends on the appropriate evaluation of merit. In 2006, we conducted an online survey of 1334 ecologists and evolutionary biologists pertaining to the review process. Respondents were from Europe, North America and other regions of the world, with the majority from English first language countries. Women comprised a third of all respondents, consistent with their representation in the scientific academic community. Among respondents we found no correlation between the time typically taken over a review and the reported average rejection rate. On average, Europeans took longer over reviewing a manuscript than North Americans, and females took longer than males, but reviewed fewer manuscripts. Males recommended rejection of manuscripts more frequently than females, regardless of region. Hence, editors and potential authors should consider alternative sets of criteria, to what exists now, when selecting a panel of referees to potentially balance different tendencies by gender or region.

There are 12 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. Here are my own picks for the week – you go and look for your own favourites:
Obesity as a Perceived Social Signal:

Fat accumulation has been classically considered as a means of energy storage. Obese people are theorized as metabolically ‘thrifty’, saving energy during times of food abundance. However, recent research has highlighted many neuro-behavioral and social aspects of obesity, with a suggestion that obesity, abdominal obesity in particular, may have evolved as a social signal. We tested here whether body proportions, and abdominal obesity in particular, are perceived as signals revealing personality traits. Faceless drawings of three male body forms namely lean, muscular and feminine, each with and without abdominal obesity were shown in a randomized order to a group of 222 respondents. A list of 30 different adjectives or short descriptions of personality traits was given to each respondent and they were asked to allocate the most appropriate figure to each of them independently. The traits included those directly related to physique, those related to nature, attitude and moral character and also those related to social status. For 29 out of the 30 adjectives people consistently attributed specific body forms. Based on common choices, the 30 traits could be clustered into distinct ‘personalities’ which were strongly associated with particular body forms. A centrally obese figure was perceived as “lethargic, greedy, political, money-minded, selfish and rich”. The results show that body proportions are perceived to reflect personality traits and this raises the possibility that in addition to energy storage, social selection may have played some role in shaping the biology of obesity.

What Should Vaccine Developers Ask? Simulation of the Effectiveness of Malaria Vaccines:

A number of different malaria vaccine candidates are currently in pre-clinical or clinical development. Even though they vary greatly in their characteristics, it is unlikely that any of them will provide long-lasting sterilizing immunity against the malaria parasite. There is great uncertainty about what the minimal vaccine profile should be before registration is worthwhile; how to allocate resources between different candidates with different profiles; which candidates to consider combining; and what deployment strategies to consider. We use previously published stochastic simulation models, calibrated against extensive epidemiological data, to make quantitative predictions of the population effects of malaria vaccines on malaria transmission, morbidity and mortality. The models are fitted and simulations obtained via volunteer computing. We consider a range of endemic malaria settings with deployment of vaccines via the Expanded program on immunization (EPI), with and without additional booster doses, and also via 5-yearly mass campaigns for a range of coverages. The simulation scenarios account for the dynamic effects of natural and vaccine induced immunity, for treatment of clinical episodes, and for births, ageing and deaths in the cohort. Simulated pre-erythrocytic vaccines have greatest benefits in low endemic settings (EIR of 84) PEV may lead to increased incidence of severe disease in the long term, if efficacy is moderate to low (20%) malaria vaccines (either PEV or BSV) when deployed through mass campaigns targeting all age-groups as well as EPI, and especially if combined with highly efficacious transmission-blocking components. We present for the first time a stochastic simulation approach to compare likely effects on morbidity, mortality and transmission of a range of malaria vaccines and vaccine combinations in realistic epidemiological and health systems settings. The results raise several issues for vaccine clinical development, in particular appropriateness of vaccine types for different transmission settings; the need to assess transmission to the vector and duration of protection; and the importance of deployment additional to the EPI, which again may make the issue of number of doses required more critical. To test the validity and robustness of our conclusions there is a need for further modeling (and, of course, field research) using alternative formulations for both natural and vaccine induced immunity. Evaluation of alternative deployment strategies outside EPI needs to consider the operational implications of different approaches to mass vaccination.