A Blog Around The Clock

We were too busy to notice, but apparently, PLoS ONE reached a new milestone this week – the 2000th article! Wow! That’s a lot!
This week we have a new Journal Club, already getting lively so you should all picth in and add your comments to the discussion. It is on the article on human evolution: Identifying Selected Regions from Heterozygosity and Divergence Using a Light-Coverage Genomic Dataset from Two Human Populations and the commentary can be found here.
And here are some titles from this week’s crop that got my attention – the first one listed being the first Taxonomy article ever published in PLoS:
A Supplementary Description of Cypridina mariae and Rediagnosis of the Genus Cylindroleberis (Ostracoda: Myodocopa: Cylindroleberididae):

The ostracod family Cylindroleberididae is based on the genus Cylindroleberis Brady, 1868, and has a complicated nomenclatural history. The type species of Cylindroleberis is Cypridina mariae Baird, 1850. Baird described only the carapace, which had been considered lost. Thus, there was no reference point for the concept C. mariae or the genus Cylindroleberis. Baird’s material has now been found in the Natural History Museum, London, U.K., and is illustrated here. To clarify the taxonomic status of C. mariae and Cylindroleberis, specimens were obtained from near the type locality, and a supplementary description is presented. This includes description of appendages, particularly the first antenna and mandible, which contain important diagnostic characters. This supplementary description provides important information about C. mariae, allowing a revision of the genus Cylindroleberis, and establishing a framework for future biological research on this ostracod group.

Does Sex Trade with Violence among Genotypes in Drosophila melanogaster?:

The evolutionary forces shaping the ability to win competitive interactions, such as aggressive encounters, are still poorly understood. Given a fitness advantage for competitive success, variance in aggressive and sexual display traits should be depleted, but a great deal of variation in these traits is consistently found. While life history tradeoffs have been commonly cited as a mechanism for the maintenance of variation, the variability of competing strategies of conspecifics may mean there is no single optimum strategy. We measured the genetically determined outcomes of aggressive interactions, and the resulting effects on mating success, in a panel of diverse inbred lines representing both natural variation and artificially selected genotypes. Males of one genotype which consistently lost territorial encounters with other genotypes were nonetheless successful against males that were artificially selected for supernormal aggression and dominated all other lines. Intransitive patterns of territorial success could maintain variation in aggressive strategies if there is a preference for territorial males. Territorial success was not always associated with male mating success however and females preferred ‘winners’ among some male genotypes, and ‘losers’ among other male genotypes. This suggests that studying behaviour from the perspective of population means may provide limited evolutionary and genetic insight. Overall patterns of competitive success among males and mating transactions between the sexes are consistent with mechanisms proposed for the maintenance of genetic variation due to nonlinear outcomes of competitive interactions.

Seasonal Activity Budget of Adult Baltic Ringed Seals:

Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated.

Optimal Foraging Predicts the Ecology but Not the Evolution of Host Specialization in Bacteriophages:

We explore the ability of optimal foraging theory to explain the observation among marine bacteriophages that host range appears to be negatively correlated with host abundance in the local marine environment. We modified Charnov’s classic diet composition model to describe the ecological dynamics of the related generalist and specialist bacteriophages φX174 and G4, and confirmed that specialist phages are ecologically favored only at high host densities. Our modified model accurately predicted the ecological dynamics of phage populations in laboratory microcosms, but had only limited success predicting evolutionary dynamics. We monitored evolution of attachment rate, the phenotype that governs diet breadth, in phage populations adapting to both low and high host density microcosms. Although generalist φX174 populations evolved even broader diets at low host density, they did not show a tendency to evolve the predicted specialist foraging strategy at high host density. Similarly, specialist G4 populations were unable to evolve the predicted generalist foraging strategy at low host density. These results demonstrate that optimal foraging models developed to explain the behaviorally determined diets of predators may have only limited success predicting the genetically determined diets of bacteriophage, and that optimal foraging probably plays a smaller role than genetic constraints in the evolution of host specialization in bacteriophages.

Seasonal Migration Determined by a Trade-Off between Predator Avoidance and Growth:

Migration is a common phenomenon in many organisms, terrestrial as well as aquatic, and considerable effort has been spent to understand the evolution of migratory behaviour and its consequences for population and community dynamics. In aquatic systems, studies on migration have mainly been focused on commercially important fish species, such as salmon and trout. However, seasonal mass-migrations may occur also among other freshwater fish, e.g. in cyprinids that leave lakes and migrate into streams and wetlands in the fall and return back to the lake in spring. In a conceptual model, we hypothesized that this is an adaptive behaviour in response to seasonal changes in predation (P) and growth (G) and that migrating fish change habitat so as to minimise the ratio between predation mortality and growth rate (P/G). Estimates from bioenergetic modelling showed that seasonal changes in the ratio between predator consumption rate and prey growth rate followed the predictions from the conceptual model and also gave more precise predictions for the timing of the habitat change. By quantifying the migration of more than 1800 individually marked fish, we showed that actual migration patterns followed predictions with a remarkable accuracy, suggesting that migration patterns have evolved in response to seasonally fluctuating trade-offs between predator avoidance and foraging gains. Thus, the conceptual model provides a mechanistic understanding to mass-migration in prey fish. Further, we also show that the dominant prey fish is actually absent from the lake during a major part of the year, which should have strong implications for the dynamics of the lake ecosystem through direct and indirect food-web interactions.

Cyclic and Sleep-Like Spontaneous Alternations of Brain State Under Urethane Anaesthesia:

Although the induction of behavioural unconsciousness during sleep and general anaesthesia has been shown to involve overlapping brain mechanisms, sleep involves cyclic fluctuations between different brain states known as active (paradoxical or rapid eye movement: REM) and quiet (slow-wave or non-REM: nREM) stages whereas commonly used general anaesthetics induce a unitary slow-wave brain state. Long-duration, multi-site forebrain field recordings were performed in urethane-anaesthetized rats. A spontaneous and rhythmic alternation of brain state between activated and deactivated electroencephalographic (EEG) patterns was observed. Individual states and their transitions resembled the REM/nREM cycle of natural sleep in their EEG components, evolution, and time frame (~11 minute period). Other physiological variables such as muscular tone, respiration rate, and cardiac frequency also covaried with forebrain state in a manner identical to sleep. The brain mechanisms of state alternations under urethane also closely overlapped those of natural sleep in their sensitivity to cholinergic pharmacological agents and dependence upon activity in the basal forebrain nuclei that are the major source of forebrain acetylcholine. Lastly, stimulation of brainstem regions thought to pace state alternations in sleep transiently disrupted state alternations under urethane. Our results suggest that urethane promotes a condition of behavioural unconsciousness that closely mimics the full spectrum of natural sleep. The use of urethane anaesthesia as a model system will facilitate mechanistic studies into sleep-like brain states and their alternations. In addition, it could also be exploited as a tool for the discovery of new molecular targets that are designed to promote sleep without compromising state alternations.

Unique Environmental Effects on Physical Activity Participation: A Twin Study:

The health benefits of regular physical activity are well established. However, the relative contribution of heritable and environmental factors to physical activity participation remains controversial. Using a cut-point of 60 minutes of total activity per week, data from the GenomEUtwin project revealed consistent genetic influence on physical activity participation in 37,051 twin pairs from seven countries. We hypothesized that the heritability of physical activity participation would be attenuated using the CDC/ACSM recommended minimum threshold of 150 minutes of moderate intensity activity per week. Data were obtained from 1,389 twin pairs from the community-based University of Washington Twin Registry. Twin similarity in physical activity participation using both cut-points was analyzed using tetrachoric correlations and structural equation modeling in all same-sex pairs. Correlations were higher in monozygotic (rMZ = 0.43, 95% CI = 0.33-0.54) than dizygotic pairs (rDZ = 0.30, 95% CI = 0.12-0.47) using the 60 minute cut-point. However, differences were attenuated using the 150 minute standard (rMZ = 0.30, 95% CI = 0.20-0.40; rDZ = 0.25, 95% CI = 0.07-0.42). Using the lower cut-point, the best fitting model of twin resemblance only included additive genetics and unique environment, with a heritability of 45%. In contrast, using the higher threshold, the best fitting model included the common and unique environment, with the unique environment contributing 72% of the variance. Unique environment factors provide the strongest influence on physical activity participation at levels recommended for health benefits.

Antioxidant Users Don’t Live Longer, Analysis Of Studies Concludes:

The vitamin industry has long touted antioxidants as a way to improve health by filling in gaps in diet, but a new review of studies found no evidence that the nutrition supplements extend life. Worse, the review authors said that some antioxidants could increase risk for death.

Researchers Mimic Bacteria To Produce Magnetic Nanoparticles:

When it comes to designing something, it’s hard to find a better source of inspiration than Mother Nature. Using that principle, a diverse, interdisciplinary group of researchers at the U.S. Department of Energy’s Ames Laboratory is mimicking bacteria to synthesize magnetic nanoparticles that could be used for drug targeting and delivery, in magnetic inks and high-density memory devices, or as magnetic seals in motors. Commercial room-temperature synthesis of ferromagnetic nanoparticles is difficult because the particles form rapidly, resulting in agglomerated clusters of particles with less than ideal crystalline and magnetic properties. Size also matters. As particles get smaller, their magnetic properties, particularly with regard to temperature, also diminish. However, several strains of bacteria produce magnetite (Fe3O4) – fine, uniform nanoparticles that have desirable magnetic properties. These magnetotactic bacteria use a protein to form crystalline particles about 50 nanometers in size. These crystals are bound by membranes to form chains of particles which the bacteria use like a compass needle to orient themselves with the Earth’s magnetic field.

Decision-making May Be Surprisingly Unconscious Activity:

Contrary to what most of us would like to believe, decision-making may be a process handled to a large extent by unconscious mental activity. A team of scientists has unraveled how the brain actually unconsciously prepares our decisions. Even several seconds before we consciously make a decision its outcome can be predicted from unconscious activity in the brain.

Community-based Approach Best Bet To Control Free-roaming Cats, Survey Suggests:

A survey gauging Ohioans’ attitudes about free-roaming cats suggests that no single statewide measure would be sufficient in managing cat overpopulation because public opinion about outdoor cats varies widely across the state.

Bikini Corals Recover From Atomic Blast, Although Some Species Missing:

Half a century after the last earth-shattering atomic blast shook the Pacific atoll of Bikini, the corals are flourishing again. Some coral species, however, appear to be locally extinct.

Fittest Males Don’t Always Get The Girl:

The fittest males don’t always get the girl, USC biologists report. Study tackles a paradox in species from fruit flies to humans: If warriors win the spoils, why don’t males evolve towards super-aggressiveness?

Deep-sea Sharks Wired For Sound:

Deep-sea sharks have been tagged and tracked and their habitats precisely mapped in world-first research to test the conservation value of areas closed to commercial fishing. Scientists from the CSIRO Wealth from Oceans National Research Flagship recently fitted acoustic tags to 50 gulper sharks, swellsharks and green eye dogfish near Port Lincoln, South Australia.

Insects Evolved Radically Different Strategy To Smell:

Darwin’s tree of life represents the path and estimates the time evolution took to get to the current diversity of life. Now, new findings suggest that this tree, an icon of evolution, may need to be redrawn. In research to be published in the April 13 advance online issue of Nature, researchers at Rockefeller University and the University of Tokyo have joined forces to reveal that insects have adopted a strategy to detect odors that is radically different from those of other organisms — an unexpected and controversial finding that may dissolve a dominant ideology in the field.

Fly Is At Home On A Crab, With New Evolutionary Neighbors:

Scientists at the Max Planck Institute for Chemical Ecology, Germany, have rediscovered Drosophila endobranchia, a fly living in the mouth of land crabs. The members of Drosophilidae, a family consisting of about 3000 species, are often referred to as fruit flies although most of the members feed on microbes. As microbes can be found growing on a wide range of substrates, fruit flies can accordingly also be found in a multitude of habitats.

Sleep, Baby, Sleep: Parents’ Behavior Has Direct Impact On Children’s Sleep Problems:

Parents who want their babies to sleep through the night would be wise to avoid co-sleeping arrangements or feeding their children evening snacks beyond early infancy. According to a Université de Montréal study the way parents put their babies to bed has a direct impact on how well children sleep when they reach four to six years old.

Shorebird Numbers Crash In Australia:

One of the world’s great wildlife spectacles is under way across Australia: as many as two million migratory shorebirds of 36 species are gathering around Broome before an amazing 10,000-kilometre annual flight to their northern hemisphere breeding grounds. But an alarming new study has revealed that both these migrants and Australia’s one million resident shorebirds have suffered a massive collapse in numbers over the past 25 years.

Shift Work Linked To Organ Disease, Study Suggests:

Disruption of an individual’s natural sleep-wake cycle has been determined to be a contributing factor in the development of organ disease. The findings of U of T researchers were recently published in the Journal of American Physiology.

Mass Media Campaigns Can Convince Young Adults To Adopt Safer Sex Practices, Study Shows:

— Two University of Kentucky researchers from the department of communication in the UK College of Communications and Information Studies have learned that targeted mass media campaigns alone can be effective in convincing high sensation-seeking, impulsive decision-making young adults to adopt safer sex practices.

Wireless EEG System Self-powered By Body Heat And Light:

The Interuniversity Microelectronics Centre, affiliated with the Holst Centre, has developed a battery-free wireless 2-channel EEG* system powered by a hybrid power supply using body heat and ambient light which could be used to monitor brain waves after a head injury. The hybrid power supply combines a thermoelectric generator that uses the heat dissipated from a person’s temples and silicon photovoltaic cells. The entire system is wearable and integrated into a device resembling headphones. The system can provide more than 1mW on average indoor, which is more than enough for the targeted application.

Stress May Lead Students To Use Stimulants:

A growing number of high school and college students are turning to stimulants like ADHD drugs and energy drinks to help them through their stress — particularly during exam time. University of Michigan experts say that misuse of stimulants can lead to serious health consequences, and encourage parents to take steps toward preventing their children from overusing stimulants.

Anticipating A Laugh Reduces Our Stress Hormones, Study Shows:

In 2006 researchers investigating the interaction between the brain, behavior, and the immune system found that simply anticipating a mirthful laughter experience boosted health-protecting hormones. Now, two years later, the same researchers have found that the anticipation of a positive humorous laughter experience also reduces potentially detrimental stress hormones. According to Dr. Lee Berk, the study team’s lead researcher of Loma Linda University, Loma Linda, CA, “Our findings lead us to believe that by seeking out positive experiences that make us laugh we can do a lot with our physiology to stay well.”

Triple Threat: Young Macho Men With Serious Injuries Often Abuse Alcohol:

Men with serious injuries, such as traumatic brain injury or spinal cord injury, must deal with a range of emotions. If these men have strong traditional masculine ideas and abuse alcohol, it becomes even more difficult to help them heal and come to terms with their emotions and situations. A University of Missouri psychology researcher studied these challenging factors to find better ways to understand and treat men who fit this mold, such as the injured soldiers coming back from Iraq and Afghanistan.