Yearly Archives: 2007

One Species’ Entire Genome Discovered Inside Another’s:

Scientists at the University of Rochester and the J. Craig Venter Institute have discovered a copy of the entire genome of a bacterial parasite residing inside the genome of its host species. The finding, reported in Science August 30, suggests that lateral gene transfer–the movement of genes between unrelated species–may happen much more frequently between bacteria and multicellular organisms than scientists previously believed, posing dramatic implications for evolution.

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Fruit Flies Prefer Fizzy Drinks:

That fruit fly hovering over your kitchen counter may be attracted to more than the bananas that are going brown; it may also want a sip of your carbonated water.

A Genetic Trigger For The Cambrian Explosion Unraveled?:

A team of scientists led by young Croatian evolutionary geneticist Tomislav Domazet-Lošo from Ruder Boškovic Institute (RBI) in Zagreb, Croatia, developed a novel methodological approach in evolutionary studies. Using the method they named ‘genomic phylostratigraphy’, its authors shed new and unexpected light on some of the long standing macroevolutionary issues, which have been puzzling evolutionary biologists since Darwin.

Wolves Find Happy Hunting Grounds In Yellowstone National Park:

If Mark Boyce could converse with elk, he might give them a word of advice: avoid open, flat, snowy areas near rivers and roads. A biological scientist at the University of Alberta, Boyce analyzed 774 wolf-elk kill sites and concluded that spatial patterns of predation between wolves and elk are more strongly influenced by landscape features than by wolf distribution.

Saving Tiny Sea Turtles Nesting By The Space Shuttle:

On Launch Pad 39A at NASA’s Kennedy Space Center in Florida, the Space Shuttle Endeavour sat bathed in glowing light, silhouetting the vehicle against the dark night sky over the seaside complex. It may sound like an awesome and idyllic scene, but not for nesting sea turtles and their newly hatched babies. During their summer nesting season, these turtles emerge from the ocean along the pristine beach within 200 yards of the space shuttle launch pads. The light emanating from the pads can deter the adults from coming ashore to lay their eggs and disorient the hatchlings as they emerge from their nests and head toward the moonlit sea.

Eating Together As A Family Creates Better Eating Habits Later In Life:

Eating together as a family during adolescence is associated with lasting positive effects on dietary quality in young adulthood, according to researchers at the University of Minnesota.

When Bivalves Ruled The World:

Before the worst mass extinction of life in Earth’s history — 252 million years ago — ocean life was diverse and clam-like organisms called brachiopods dominated. After the calamity, when little else existed, a different kind of clam-like organism, called a bivalve, took over.

Baiji Dolphin Previously Thought Extinct Spotted In The Yangtze River:

The reported sighting of a Yangtze River dolphin, or Baiji, means there is still a chance for people to take further action and protect the cetaceans in the Yangtze from extinction, according to World Wildlife Fund.

Humpback Whales Recorded Clicking And Buzzing While Feeding For First Time:

For the first time, researchers have recorded “megapclicks” — a series of clicks and buzzes from humpback whales apparently associated with nighttime feeding behaviors — in and around NOAA’s Stellwagen Bank National Marine Sanctuary.

Mystery Of A Third Olfactory System Unlocked:

Researchers at the University of Maryland School of Medicine have found a “nose within the nose,” a unique olfactory system within the noses of mice that is able to “smell” hormones involved in regulating water and salt balance in the body. This research may lead to new insights into the complex system of “chemical communication” between individuals.

First Orchid Fossil Puts Showy Blooms At Some 80 Million Years Old:

Biologists at Harvard University have identified the ancient fossilized remains of a pollen-bearing bee as the first hint of orchids in the fossil record, a find they say suggests orchids are old enough to have co-existed with dinosaurs.

Amber Specimen Captures Ancient Chemical Battle:

It appears that chemical warfare has been around a lot longer than poison arrows, mustard gas or nerve weapons — about 100 million years, give or take a little.

Household Mold Linked To Depression:

A groundbreaking public health study has found a connection between damp, moldy homes and depression. The study, led by Brown University epidemiologist Edmond Shenassa, is the largest investigation of an association between mold and mood and is the first such investigation conducted outside the United Kingdom.

Social Parasites Of The Smaller Kind:

Cooperation is widespread in the natural world but so too are cheats — mutants that do not contribute to the collective good but simply reap the benefits of others’ cooperative efforts. In evolutionary terms, cheats should indeed prosper, so how cooperation persists despite the threat of cheat takeover is a fundamental question. Recently, biologists at the Universities of Edinburgh and Oxford have found that in bacteria, cheats actually orchestrate their own downfall.

Cats Do Suffer From Arthritis, Study Shows:

New research at the University of Glasgow has found that arthritis in cats is far more common than previously thought.

There are 32 new articles on PLoS ONE this week. Here are some titles that caught my eye – go read, rate, annotate and comment:
Why Men Matter: Mating Patterns Drive Evolution of Human Lifespan:

Evolutionary theory predicts that senescence, a decline in survival rates with age, is the consequence of stronger selection on alleles that affect fertility or mortality earlier rather than later in life. Hamilton quantified this argument by showing that a rare mutation reducing survival is opposed by a selective force that declines with age over reproductive life. He used a female-only demographic model, predicting that female menopause at age ca. 50 yrs should be followed by a sharp increase in mortality, a “wall of death.” Human lives obviously do not display such a wall. Explanations of the evolution of lifespan beyond the age of female menopause have proven difficult to describe as explicit genetic models. Here we argue that the inclusion of males and mating patterns extends Hamilton’s theory and predicts the pattern of human senescence. We analyze a general two-sex model to show that selection favors survival for as long as men reproduce. Male fertility can only result from matings with fertile females, and we present a range of data showing that males much older than 50 yrs have substantial realized fertility through matings with younger females, a pattern that was likely typical among early humans. Thus old-age male fertility provides a selective force against autosomal deleterious mutations at ages far past female menopause with no sharp upper age limit, eliminating the wall of death. Our findings illustrate the evolutionary importance of males and mating preferences, and show that one-sex demographic models are insufficient to describe the forces that shape human senescence.

Phylogenomics Reshuffles the Eukaryotic Supergroups:

Resolving the phylogenetic relationships between eukaryotes is an ongoing challenge of evolutionary biology. In recent years, the accumulation of molecular data led to a new evolutionary understanding, in which all eukaryotic diversity has been classified into five or six supergroups. Yet, the composition of these large assemblages and their relationships remain controversial.
Here, we report the sequencing of expressed sequence tags (ESTs) for two species belonging to the supergroup Rhizaria and present the analysis of a unique dataset combining 29908 amino acid positions and an extensive taxa sampling made of 49 mainly unicellular species representative of all supergroups. Our results show a very robust relationship between Rhizaria and two main clades of the supergroup chromalveolates: stramenopiles and alveolates. We confirm the existence of consistent affinities between assemblages that were thought to belong to different supergroups of eukaryotes, thus not sharing a close evolutionary history.
This well supported phylogeny has important consequences for our understanding of the evolutionary history of eukaryotes. In particular, it questions a single red algal origin of the chlorophyll-c containing plastids among the chromalveolates. We propose the abbreviated name ‘SAR’ (Stramenopiles+Alveolates+Rhizaria) to accommodate this new super assemblage of eukaryotes, which comprises the largest diversity of unicellular eukaryotes.

Quadrupling Muscle Mass in Mice by Targeting TGF-ß Signaling Pathways:

Myostatin is a transforming growth factor-ß family member that normally acts to limit skeletal muscle growth. Mice genetically engineered to lack myostatin activity have about twice the amount of muscle mass throughout the body, and similar effects are seen in cattle, sheep, dogs, and a human with naturally occurring loss-of-function mutations in the myostatin gene. Hence, there is considerable interest in developing agents capable of inhibiting myostatin activity for both agricultural and human therapeutic applications. We previously showed that the myostatin binding protein, follistatin, can induce dramatic increases in muscle mass when overexpressed as a transgene in mice. In order to determine whether this effect of follistatin results solely from inhibition of myostatin activity, I analyzed the effect of this transgene in myostatin-null mice. Mstn−/− mice carrying a follistatin transgene had about four times the muscle mass of wild type mice, demonstrating the existence of other regulators of muscle mass with similar activity to myostatin. The greatest effect on muscle mass was observed in offspring of mothers homozygous for the Mstn mutation, raising the possibility that either myostatin itself or a downstream regulator may normally be transferred from the maternal to fetal circulations. These findings demonstrate that the capacity for increasing muscle growth by manipulating TGF-ß signaling pathways is much more extensive than previously appreciated and suggest that muscle mass may be controlled at least in part by a systemic mode of action of myostatin.

Insights from Amphioxus into the Evolution of Vertebrate Cartilage:

Central to the story of vertebrate evolution is the origin of the vertebrate head, a problem difficult to approach using paleontology and comparative morphology due to a lack of unambiguous intermediate forms. Embryologically, much of the vertebrate head is derived from two ectodermal tissues, the neural crest and cranial placodes. Recent work in protochordates suggests the first chordates possessed migratory neural tube cells with some features of neural crest cells. However, it is unclear how and when these cells acquired the ability to form cellular cartilage, a cell type unique to vertebrates. It has been variously proposed that the neural crest acquired chondrogenic ability by recruiting proto-chondrogenic gene programs deployed in the neural tube, pharynx, and notochord. To test these hypotheses we examined the expression of 11 amphioxus orthologs of genes involved in neural crest chondrogenesis. Consistent with cellular cartilage as a vertebrate novelty, we find that no single amphioxus tissue co-expresses all or most of these genes. However, most are variously co-expressed in mesodermal derivatives. Our results suggest that neural crest-derived cartilage evolved by serial cooption of genes which functioned primitively in mesoderm.

The Antibacterial Protein Lysozyme Identified as the Termite Egg Recognition Pheromone:

Social insects rely heavily on pheromone communication to maintain their sociality. Egg protection is one of the most fundamental social behaviours in social insects. The recent discovery of the termite-egg mimicking fungus ‘termite-ball’ and subsequent studies on termite egg protection behaviour have shown that termites can be manipulated by using the termite egg recognition pheromone (TERP), which strongly evokes the egg-carrying and -grooming behaviours of workers. Despite the great scientific and economic importance, TERP has not been identified because of practical difficulties. Herein we identified the antibacterial protein lysozyme as the TERP.

Corpus Callosum Morphology in Capuchin Monkeys Is Influenced by Sex and Handedness:

Sex differences have been reported in both overall corpus callosum area and its regional subdivisions in humans. Some have suggested this reflects a unique adaptation in humans, as similar sex differences in corpus callosum morphology have not been reported in any other species of primate examined to date. Furthermore, an association between various measurements of corpus callosum morphology and handedness has been found in humans and chimpanzees. In the current study, we report measurements of corpus callosum cross-sectional area from midsagittal MR images collected in vivo from 14 adult capuchin monkeys, 9 of which were also characterized for hand preference on a coordinated bimanual task. Adult females were found to have a significantly larger corpus callosum: brain volume ratio, rostral body, posterior midbody, isthmus, and splenium than adult males. Left-handed individuals had a larger relative overall corpus callosum area than did right-handed individuals. Additionally, a significant sex and handedness interaction was found for anterior midbody, with right-handed males having a significantly smaller area than right-handed females. These results suggest that sex and handedness influences on corpus callosum morphology are not restricted to Homo sapiens.

Simple Sequence Repeats Provide a Substrate for Phenotypic Variation in the Neurospora crassa Circadian Clock:

WHITE COLLAR-1 (WC-1) mediates interactions between the circadian clock and the environment by acting as both a core clock component and as a blue light photoreceptor in Neurospora crassa. Loss of the amino-terminal polyglutamine (NpolyQ) domain in WC-1 results in an arrhythmic circadian clock; this data is consistent with this simple sequence repeat (SSR) being essential for clock function.
Since SSRs are often polymorphic in length across natural populations, we reasoned that investigating natural variation of the WC-1 NpolyQ may provide insight into its role in the circadian clock. We observed significant phenotypic variation in the period, phase and temperature compensation of circadian regulated asexual conidiation across 143 N. crassa accessions. In addition to the NpolyQ, we identified two other simple sequence repeats in WC-1. The sizes of all three WC-1 SSRs correlated with polymorphisms in other clock genes, latitude and circadian period length. Furthermore, in a cross between two N. crassa accessions, the WC-1 NpolyQ co-segregated with period length.
Natural variation of the WC-1 NpolyQ suggests a mechanism by which period length can be varied and selected for by the local environment that does not deleteriously affect WC-1 activity. Understanding natural variation in the N. crassa circadian clock will facilitate an understanding of how fungi exploit their environments.

Super Spiders Make Bolder Birds:

Recent research has revealed that by feeding spiders to their chicks, birds can manipulate the personality and learning ability of their young. In a report recently published in the journal Proceedings of the Royal Society B, University of Glasgow researchers reveal that birds preferentially feed their young spiders containing taurine.
Taurine is an amino acid which is also found in breast milk and energy drinks. The beneficial qualities of taurine include aiding the development of premature babies and reducing blood pressure in human adults, but it has not previously been known how taurine influences the development of birds.
By comparing the behaviour of wild blue tits that were fed a taurine supplement, mimicking a diet rich in spiders, with blue tits that were not, researchers were able to observe the long term impacts of this vital nutrient.

Sleep Apnea Treatment Option: Innovative Surgery:

Sleep disorder and ear, nose and throat specialists at Thomas Jefferson University are examining an innovative procedure to treat obstructive sleep apnea syndrome.

New Light-sensing Ability Discovered In Disease-causing Bacteria:

The bacteria that cause brucellosis can sense light and use the information to regulate their virulence, according to a study in the August 24 issue of the journal Science. The discovery comes after 120 years of research into the disease, which causes abortions in livestock and fevers in humans. Researchers found that two other bacteria, including a species that attacks plants, sense light using the same type of protein structure, and at least 94 more species possess the code for it in their DNA.

‘Mighty Mice’ Made Mightier:

The Johns Hopkins scientist who first showed that the absence of the protein myostatin leads to oversized muscles in mice and men has now found a second protein, follistatin, whose overproduction in mice lacking myostatin doubles the muscle-building effect.

New Golden Frog Discovered In Remote Region Of Colombia:

A new poisonous frog was recently discovered in a remote mountainous region in Colombia by a team of young scientists supported by the Conservation Leadership Programme (CLP). The new frog, which is almost two centimetres in length, was given the name the “golden frog of Supatá.”

Saving The Remarkable Kakapo Bird From Extinction:

One of the strangest and most endangered birds in the world, the kakapo, is being brought back from the brink of extinction with the help of scientists from the University of Glasgow.

The Molecular Anatomy of Spontaneous Germline Mutations in Human Testes:

The frequency of Apert syndrome mutations is 100-1,000 times higher than expected from average mutation rates, and it is due to positive selection in the testis increasing the frequency of germ cells carrying the defect.

Enlightening Energy Parasitism by Analysis of an ATP/ADP Transporter from Chlamydiae:

This paper explores the functional basis of how the intracellular P. amoebophila manages to effectively exploit the energy pool of its host cell by using the nucleotide transporter PamNTT1.

Emergence of Large-Scale Cell Morphology and Movement from Local Actin Filament Growth Dynamics:

Mathematical modeling predicts global modifications of the shape and behavior of migrating cells from knowledge of detailed multiscale protein interactions.

Qualitative Research: Understanding Patients’ Needs and Experiences:

Why do up to half of all patients with tuberculosis (TB) fail to adhere to drug treatment [1]? The answer to this question is a matter of life and death, since nonadherence contributes to disease relapse and mortality.

Setting Priorities in Child Health Research Investments for South Africa:

This paper aims to define health research priorities in South Africa, where it is estimated that nearly 100,000 children under 5 years of age still die each year.

Echidna’s Sex Life Under Study:

A University of Adelaide-led project will study the genetic makeup of one of Australia’s most iconic animals, the echidna, to give an unprecedented insight into their sex life and behaviour. World echidna expert Dr Peggy Rismiller and geneticist Dr Frank Grützner will collaborate with the Monarto and Adelaide Zoos and South Australian Museum to learn more about these unique egg-laying mammals known as monotremes.

Sharks’ ‘Bite Force’ Under The Spotlight:

While sharks instill fear in beachgoers worldwide, they instill a deep sense of curiosity in UT assistant professor and shark expert Dan Huber. There are still many mysteries surrounding what makes sharks such perfect predators, so Huber’s research on sharks’ “bite force” – their hunting performance – may offer new insights on sharks’ habits, capabilities and evolution. The research may also lead to advances in protective swimwear, shark-proofing equipment and a better understanding of flexible cartilage – which forms the sharks’ whole skeletons, much like human ears and noses.

Pollution Harms Top Marine Predators:

A new study provides some of the first evidence that albatrosses in the North Pacific may be affected by environmental contamination. Alterations in the immune function of the black-footed albatross were associated with elevated blood levels of nonpoint source contaminants. Nonpoint source pollution comes from a wide variety of sources such as farms, cars, roads and highways, and lawns. This kind of pollution is ubiquitous and can pose a significant threat to wildlife.

Monkeys Use ‘Baby Talk’ To Interact With Infants:

Female rhesus monkeys use special vocalizations while interacting with infants, the way human adults use motherese, or “baby talk,” to engage babies’ attention, new research at the University of Chicago shows. “Motherese is a high pitched and musical form of speech, which may be biological in origin,” said Dario Maestripieri, Associate Professor in Comparative Human Development at the University. “The acoustic structure of particular monkey vocalizations called girneys may be adaptively designed to attract young infants and engage their attention, similar to how the acoustic structure of human motherese, or baby talk, allows adults to visually or socially engage with infants.”

Wind Turbine Has Switch To Move Clear Of Migrating Birds:

The wind turbine off in the distance is flopped over on its side – the 11-foot blades suspended just above the ground at one end and a 2,000-pound, bulbous, galvanized steel counterbalance pitched into the air at the other. The unique turbine isn’t broken; it was lowered from a height of 80 feet to test the ability to bring it down at the drop of a hat should foul weather set in or should the migratory songbirds and nesting seabirds that frequent this 95-acre island run afoul of the whirling blades.

Mouse Vision Has A Rhythm All Its Own:

In the eyes of mammals, visual information is processed on a daily schedule set within the eyes themselves–not one dictated by the brain, according to a new report in the journal Cell. The researchers found in mice that the eyes’ normal rhythmic response to light requires only that a molecular “clock” inside the retina go on ticking. The retina is a layer of nerve tissue covering the back of the eyeball, which is often likened to the film in a camera; without it, images can’t be captured.

How Snakes Survive Starvation:

Starving snakes employ novel survival strategies not seen before in vertebrates, according to research conducted by a University of Arkansas biologist. These findings could be used in conservation strategies to determine the health of snake populations.

Giant Panda Can Survive:

The giant panda is not at an “evolutionary dead end” and could have a long term viable future, according to new research involving scientists from Cardiff University.

Viagra Increases Release Of Key Reproductive Hormone, Study Finds:

Researchers at the University of Wisconsin-Madison report this month that sildenafil increases the amount of oxytocin released by stimulation of the posterior pituitary gland, a small structure directly underneath the brain that regulates hormone levels in response to neural signals.

Mice Provide Important Clues To Obsessive-compulsive Disorder:

Mice born without a key brain protein compulsively groom their faces until they bleed and are afraid to venture out of the corner of their cages. When given a replacement dose of the protein in a specific region of the brain, or the drugs used to treat humans suffering from obsessive-compulsive disorder (OCD), many of these mice seem to get better.

Brain Research Shows Why Long-term Drug Users Just Can’t Say No:

New research from the University of Melbourne has shed new light on why long term drug users find it hard to say no, despite dire consequences to their health. A study into the frontal cortex, the key region of the brain involved in decision making, has shown that drug users have to place much greater demand on the brain to control impulses.

Longer Life? ‘Longevity’ Genes Protect Very Old People From The Bad Genes’ Harmful Effects:

People who live to 100 or more are known to have just as many–and sometimes even more–harmful gene variants compared with younger people. Now, scientists at the Albert Einstein College of Medicine of Yeshiva University have discovered the secret behind this paradox: favorable “longevity” genes that protect very old people from the bad genes’ harmful effects. The novel method used by the researchers could lead to new drugs to protect against age-related diseases.

Tone Deafness Explained:

Do people cringe when you sing? You’ve got company. But researchers have found that only 1 in 20 people truly has amusia, the technical term for tone deafness. Tests have shown that some people with bad singing voices hear music just fine. Amusics are a smaller group with a perceptual problem: They can’t pick out differences in pitch or follow the simplest tunes, reports the September 2007 issue of the Harvard Health Letter.

Crested Auklet Birds Rub Tick-repelling Perfume On Their Mates During Courtship:

Hitting it off with members of the opposite sex takes chemistry. University of Alaska Fairbanks researcher Hector Douglas has found that, for crested auklets, chemistry has both amorous and practical applications. The birds rub a citrus-like scent, secreted in wick-like feathers on their backs, on each other during courtship, a behavior called alloanointing. It is well known among some mammals, such as peccaries, but until now was not documented among birds. His research also indicates that the behavior could help protect the birds from parasites, such as ticks.

Natural Insecticide Re-created In The Lab:

Twenty-two years of dedicated research has finally resulted in success: In the journal Angewandte Chemie, a British team headed by Steven V. Ley at the University of Cambridge reports the first synthesis of azadirachtin, a natural compound that stops predatory insects from feeding.

Martian Life? Small Percentage Of Martian Soil Samples Could Have Biological Origin:

A new interpretation of data from NASA’s Viking landers indicates that 0.1% of the Martian soil tested could have a biological origin.

Are Homosexual Civil Unions A 600-year-old Tradition?:

A compelling new study from the September issue of the Journal of Modern History reviews historical evidence, including documents and gravesites, suggesting that homosexual civil unions may have existed six centuries ago in France. The article is the latest from the ongoing “Contemporary Issues in Historical Perspective” series, which explores the intersection between historical knowledge and current affairs.

First Out-of-body Experience Induced In Laboratory Setting:

A neuroscientist working at UCL (University College London) has devised the first experimental method to induce an out-of-body experience in healthy participants. In a paper published in Science, Dr Henrik Ehrsson, UCL Institute of Neurology, outlines the unique method by which the illusion is created and the implications of its discovery.