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So, let’s see what was new in PLoS Genetics, PLoS Computational Biology, PLoS Pathogens, PLoS ONE and PLoS Neglected Tropical Diseases last 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:

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Earth’s Magnetic Field Reversals Illuminated By Lava Flows Study:

Earth’s north magnetic pole is shifting and weakening. Ancient lava flows are guiding a better understanding of what generates and controls the Earth’s magnetic field – and what may drive it to occasionally reverse direction.
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Current evidence suggests we are now approaching one of these transitional states because the main magnetic field is relatively weak and rapidly decreasing, he says. While the last polarity reversal occurred several hundred thousand years ago, the next might come within only a few thousand years.

Mother Of A Goose! Giant Ocean-going Geese With Bony-teeth Once Roamed Across SE England:

A 50 million year old skull reveals that huge birds with a 5 metre wingspan once skimmed across the waters that covered what is now London, Essex and Kent. These giant ocean-going relatives of ducks and geese also had a rather bizarre attribute for a bird: their beaks were lined with bony-teeth.

From One Laying To Another, The Female Collembolan Adapts Its Eggs To Environmental Constraints:

Reproductive plasticity – the ability of individuals to modify their reproduction and the characteristics of their progeny according to environmental or social conditions – is a crucial factor in the demographics of animal populations, including man.

Weak Bladders Deter Many Young Women From Sports Participation:

A weak bladder is putting many young women off participating in sport, or prompting them to give it up altogether, suggests new research.

Captive Breeding Introduced Infectious Disease To Mallorcan Amphibians:

A potentially deadly fungus that can kill frogs and toads was inadvertently introduced into Mallorca by a captive breeding programme that was reintroducing a rare species of toad into the wild, according to a new study in the journal Current Biology.

Australian Frog Species Chooses Not To Put Eggs In One Basket:

A groundbreaking new study into the mating and nesting practices of a common Australian frog has found they partner up to eight males sequentially – the highest recorded of any vertebrate.

Animals Farmed For Meat Are The No. 1 Source Of Food Poisoning Bug, Study Shows:

A study by researchers from Lancashire, England, and Chicago, IL, found that 97 percent of campylobacteriosis cases sampled in Lancashire were caused by bacteria typically found in chicken and livestock. The work is based on DNA-sequence comparison of thousands of bacteria collected from human patients and animal carriers.

Bees Can Mediate Escape Of Genetically Engineered Material Over Several Kilometers:

A study by scientists from the Nairobi-headquartered international research centre icipe, in collaboration with the French Institut de Recherche pour le Développement (IRD) has established that bees have the potential to mediate the escape of transgenes (genetically engineered material) from crops to their wild relatives over several kilometres.

Bats Pick Up Rustling Sounds Against Highway Background Noise:

When bats go hunting by listening for faint rustling sounds made by their quarry on a quiet night they don’t have any problems. But what happens when a bat goes foraging next to a noisy highway? Can they still hear the faint sounds?

America’s Smallest Dinosaur Uncovered:

An unusual breed of dinosaur that was the size of a chicken, ran on two legs and scoured the ancient forest floor for termites is the smallest dinosaur species found in North America, according to a University of Calgary researcher who analyzed bones found during the excavation of an ancient bone bed near Red Deer, Alberta.

Growing Up Too Fast May Mean Dying Young In Honey Bees:

New study shows that transitions to aerobically-expensive behaviors in organisms living free in nature can have important consequences affecting the pace of aging.

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There are 6 new articles in PLoS ONE today – and one of them has nothing to do with biology or medicine (ONE is meant to be for all areas of science, after all). 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:
In Situ Observation of Modulated Light Emission of Fiber Fuse Synchronized with Void Train over Hetero-Core Splice Point:

Fiber fuse is a process of optical fiber destruction under the action of laser radiation, found 20 years ago. Once initiated, opical discharge runs along the fiber core region to the light source and leaves periodic voids whose shape looks like a bullet pointing the direction of laser beam. The relation between damage pattern and propagation mode of optical discharge is still unclear even after the first in situ observation three years ago. Fiber fuse propagation over hetero-core splice point (Corning SMF-28e and HI 1060) was observed in situ. Sequential photographs obtained at intervals of 2.78 µs recorded a periodic emission at the tail of an optical discharge pumped by 1070 nm and 9 W light. The signal stopped when the discharge ran over the splice point. The corresponding damage pattern left in the fiber core region included a segment free of periodicity. The spatial modulation pattern of the light emission agreed with the void train formed over the hetero-core splice point. Some segments included a bullet-shaped void pointing in the opposite direction to the laser beam propagation although the sequential photographs did not reveal any directional change in the optical discharge propagation.

Single-Species Microarrays and Comparative Transcriptomics:

Prefabricated expression microarrays are currently available for only a few species but methods have been proposed to extend their application to comparisons between divergent genomes. Here we demonstrate that the hybridization intensity of genomic DNA is a poor basis on which to select unbiased probes on Affymetrix expression arrays for studies of comparative transcriptomics, and that doing so produces spurious results. We used the Affymetrix Xenopus laevis microarray to evaluate expression divergence between X. laevis, X. borealis, and their F1 hybrids. When data are analyzed with probes that interrogate only sequences with confirmed identity in both species, we recover results that differ substantially analyses that use genomic DNA hybridizations to select probes. Our findings have implications for the experimental design of comparative expression studies that use single-species microarrays, and for our understanding of divergent expression in hybrid clawed frogs. These findings also highlight important limitations of single-species microarrays for studies of comparative transcriptomics of polyploid species.

Species Specificity in Major Urinary Proteins by Parallel Evolution:

Species-specific chemosignals, pheromones, regulate social behaviors such as aggression, mating, pup-suckling, territory establishment, and dominance. The identity of these cues remains mostly undetermined and few mammalian pheromones have been identified. Genetically-encoded pheromones are expected to exhibit several different mechanisms for coding 1) diversity, to enable the signaling of multiple behaviors, 2) dynamic regulation, to indicate age and dominance, and 3) species-specificity. Recently, the major urinary proteins (Mups) have been shown to function themselves as genetically-encoded pheromones to regulate species-specific behavior. Mups are multiple highly related proteins expressed in combinatorial patterns that differ between individuals, gender, and age; which are sufficient to fulfill the first two criteria. We have now characterized and fully annotated the mouse Mup gene content in detail. This has enabled us to further analyze the extent of Mup coding diversity and determine their potential to encode species-specific cues.
Our results show that the mouse Mup gene cluster is composed of two subgroups: an older, more divergent class of genes and pseudogenes, and a second class with high sequence identity formed by recent sequential duplications of a single gene/pseudogene pair. Previous work suggests that truncated Mup pseudogenes may encode a family of functional hexapeptides with the potential for pheromone activity. Sequence comparison, however, reveals that they have limited coding potential. Similar analyses of nine other completed genomes find Mup gene expansions in divergent lineages, including those of rat, horse and grey mouse lemur, occurring independently from a single ancestral Mup present in other placental mammals. Our findings illustrate that increasing genomic complexity of the Mup gene family is not evolutionarily isolated, but is instead a recurring mechanism of generating coding diversity consistent with a species-specific function in mammals.