Author Archives: Bora Zivkovic

There are 34 articles published in PLoS ONE this week. As always, look around, read, rate, comment, annotate…. Here are my picks for the week (no need to repeat the dinosaur paper here, of course):
A Viscoelastic Deadly Fluid in Carnivorous Pitcher Plants:

Carnivorous pitcher plants supplement their nutrient intake by trapping and digesting insects in what were thought to be passive pitfall traps. But in this study, the authors show that the pitchers of plants Nepenthes rafflesiana in fact employ highly specialized secretions to doom their victims. They show that this fluid, even when diluted, has the perfect viscoelastic properties to prevent the escape of any small creatures that come into contact with it.

The Golden Beauty: Brain Response to Classical and Renaissance Sculptures:

Speculation and debate often surround the question of whether the experience of beauty in art is based upon objective biological factors or individual subjective perception. In this study, a group of researchers attempted to answer this question by measuring brain activity in people who were exposed to original and modified images of masterpieces of Classical and Renaissance sculpture. The results suggest that in naïve art observers, a sense of beauty is determined by both objective beauty and emotional experiences.

The Effect of Real-World Personal Familiarity on the Speed of Face Information Processing:

In this study, Balas and colleagues investigated whether people’s ability to process basic information about other individuals’ faces (for example, making a decision on the individual’s gender, identity, or orientation of the image) is affected by whether they know that person. The results showed, surprisingly, that real-world familiarity with an individual helps a person to process visual cues relating to that individual faster, even if identity is not required for performing that task. These findings highlight the importance of experience and familiarity in determining visual recognition processes.

Reappraisal of Vipera aspis Venom Neurotoxicity:

The variation of venom composition with geography is an important aspect of intraspecific variability in the Vipera genus, although causes of this variability remain unclear. The diversity of snake venom is important both for our understanding of venomous snake evolution and for the preparation of relevant antivenoms to treat envenomations. A geographic intraspecific variation in snake venom composition was recently reported for Vipera aspis aspis venom in France. Since 1992, cases of human envenomation after Vipera aspis aspis bites in south-east France involving unexpected neurological signs were regularly reported. The presence of genes encoding PLA2 neurotoxins in the Vaa snake genome led us to investigate any neurological symptom associated with snake bites in other regions of France and in neighboring countries. In parallel, we used several approaches to characterize the venom PLA2 composition of the snakes captured in the same areas. We conducted an epidemiological survey of snake bites in various regions of France. In parallel, we carried out the analysis of the genes and the transcripts encoding venom PLA2s. We used SELDI technology to study the diversity of PLA2 in various venom samples. Neurological signs (mainly cranial nerve disturbances) were reported after snake bites in three regions of France: Languedoc-Roussillon, Midi-Pyrénées and Provence-Alpes-Côte d’Azur. Genomes of Vipera aspis snakes from south-east France were shown to contain ammodytoxin isoforms never described in the genome of Vipera aspis from other French regions. Surprisingly, transcripts encoding venom neurotoxic PLA2s were found in snakes of Massif Central region. Accordingly, SELDI analysis of PLA2 venom composition confirmed the existence of population of neurotoxic Vipera aspis snakes in the west part of the Massif Central mountains. The association of epidemiological studies to genetic, biochemical and immunochemical analyses of snake venoms allowed a good evaluation of the potential neurotoxicity of snake bites. A correlation was found between the expression of neurological symptoms in humans and the intensity of the cross-reaction of venoms with anti-ammodytoxin antibodies, which is correlated with the level of neurotoxin (vaspin and/or ammodytoxin) expression in the venom. The origin of the two recently identified neurotoxic snake populations is discussed according to venom PLA2 genome and transcriptome data.

Season of Birth and Dopamine Receptor Gene Associations with Impulsivity, Sensation Seeking and Reproductive Behaviors:

Season of birth (SOB) has been associated with many physiological and psychological traits including novelty seeking and sensation seeking. Similar traits have been associated with genetic polymorphisms in the dopamine system. SOB and dopamine receptor genetic polymorphisms may independently and interactively influence similar behaviors through their common effects on the dopaminergic system. Based on a sample of 195 subjects, we examined whether SOB was associated with impulsivity, sensation seeking and reproductive behaviors. Additionally we examined potential interactions of dopamine receptor genes with SOB for the same set of traits. Phenotypes were evaluated using the Sociosexual Orientation Inventory, the Barratt Impulsivity Scale, the Eysenck Impulsivity Questionnaire, the Sensation Seeking Scale, and the Delay Discounting Task. Subjects were also asked about their age at first sex as well as their desired age at the birth of their first child. The dopamine gene polymorphisms examined were Dopamine Receptor D2 (DRD2) TaqI A and D4 (DRD4) 48 bp VNTR. Primary analyses included factorial gender×SOB ANOVAs or binary logistic regression models for each dependent trait. Secondary analysis extended the factorial models by also including DRD2 and DRD4 genotypes as independent variables. Winter-born males were more sensation seeking than non-winter born males. In factorial models including both genotype and season of birth as variables, two previously unobserved effects were discovered: (1) a SOB×DRD4 interaction effect on venturesomeness and (2) a DRD2×DRD4 interaction effect on sensation seeking. These results are consistent with past findings that SOB is related to sensation seeking. Additionally, these results provide tentative support for the hypothesis that SOB modifies the behavioral expression of dopaminergic genetic polymorphism. These findings suggest that SOB should be included in future studies of risky behaviors and behavioral genetic studies of the dopamine system.

‘Noah’s Flood’ Kick-started European Farming?:

The flood believed to be behind the Noah’s Ark myth kick-started European agriculture, according to new research by the Universities of Exeter, UK and Wollongong, Australia. New research assesses the impact of the collapse of the North American (Laurentide) Ice Sheet, 8000 years ago. The results indicate a catastrophic rise in global sea level led to the flooding of the Black Sea and drove dramatic social change across Europe.

Earliest Chocolate Drink Of The New World:

The earliest known use of cacao–the source of our modern day chocolate–has been pushed back more than 500 years, to somewhere between 1400 and 1100 B.C.E., thanks to new chemical analyses of residues extracted from pottery excavated at an archaeological site at Puerto Escondido in Honduras. The new evidence also indicates that, long before the flavor of the cacao seed (or bean) became popular, it was the sweet pulp of the chocolate fruit, used in making a fermented (5% alcohol) beverage, which first drew attention to the plant in the Americas.

Octopus And Kin Inspire New Camouflage Strategies For Military Applications:

Researchers are studying the remarkable shape- and color-changing abilities of the octopus and its close relatives in an effort to understand one of nature’s most remarkable feats of camouflage and self-preservation.

New Evidence For Female Control In Reproduction:

Adding another layer of competition to the mating game, scientists are reporting possible biochemical proof that the reproductive system of female mammals can “sense” the presence of sperm and react to it by changing the uterine environment. This may be the molecular mechanism behind post-copulatory sexual selection, in which females that have mated with several partners play a role in determining which sperm fertilizes their egg.

Earlier Bites By Uninfected Mosquitoes Boost West Nile Deaths In Lab Mice:

There’s one more reason to try to avoid being bitten by mosquitoes, scientists have discovered: bites from mosquitoes that aren’t infected by the West Nile virus may make the disease worse in people who acquire it later from West Nile-infected mosquitoes.

Sunbathing Tree Frogs’ Future Under A Cloud:

Animal conservationists in Manchester are turning to physics to investigate whether global warming is responsible for killing sun-loving South American tree frogs.

Like Father, Like Son: Attractiveness Is Hereditary:

Sexy dads produce sexy sons, in the insect world at least. While scientists already knew that specific attractive traits, from cricket choruses to peacocks’ tails, are passed on to their offspring, the heritability of attractiveness as a whole is more contentious. Now, new research by the University of Exeter shows that attractiveness is hereditary.

Evolution Is Deterministic, Not Random, Biologists Conclude From Multi-species Study:

A multi-national team of biologists has concluded that developmental evolution is deterministic and orderly, rather than random, based on a study of different species of roundworms.

Greg Laden explains.
Telecommuting Has Mostly Positive Consequences For Employees And Employers:

Telecommuting is a win-win for employees and employers, resulting in higher morale and job satisfaction and lower employee stress and turnover. These were among the conclusions of psychologists who examined 20 years of research on flexible work arrangements.

Yes, I know. It’s true.
Gene In Male Fish Lures Females Into Sex:

A gene has been found in male cichlid fish that evolved to lure female fish so that male cichlids can deposit sperm in the females mouths. A study in the online open access journal BMC Biology reveals that the gene is associated with egg-like markings on the fins of cichlid fishes and uncovers the evolutionary history of these markings, which are central to the success of the fishes’ exotic oral mating behaviour.

Evolutionary Biology Research On Plant Shows Significance Of Maternal Effects:

When habitat changes, animals migrate. But how do immobile organisms like plants cope when faced with alterations to their environment? This is an increasingly important question in light of new environmental conditions brought on by global climate change.

Monday night is the time when new articles on PLoS Medicine and PLoS Biology get published. My picks for this week:
Who Needs Cause-of-Death Data:

More than half of the world’s deaths pass by undocumented as to cause. Whilst the appropriate focus of health services may well be the care of the living, consistent and reliable cause-of-death data also constitute a crucial and major resource for health planning and prioritisation, and their lack in many settings is a major concern.

Complex Regulation of cyp26a1 Creates a Robust Retinoic Acid Gradient in the Zebrafish Embryo:

The formation of gradients of morphogens, signaling molecules that determine cell fates in a concentration-dependent manner, is a fundamental process in developmental biology. Several morphogens pattern the anterior-posterior (head to tail) axis of the vertebrate nervous system, including the vitamin A derivative, retinoic acid (RA) and fibroblast growth factors (Fgfs). However, it remains unclear how the activities of such morphogen gradients are coordinated. We have addressed this question by combining genetic experiments in zebrafish and computational analyses. We show that RA acts as a graded signal over long distances and that its gradient is shaped, to a large extent, by local control of RA degradation. In particular, RA promotes and Fgf suppresses RA degradation, thereby linking the shapes of RA and Fgf gradients. Computational models suggest that this linkage helps make RA-mediated patterning robust to changes in the rate at which RA is synthesized (which may vary with levels of dietary vitamin A) as well as in the size and shape of the embryo during development. Analogous regulatory loops may be used for similar purposes in other tissues in which RA and Fgfs interact, as well as in other morphogen systems.

Hormone Of Darkness: Melatonin Could Hurt Memory Formation At Night:

What do you do when a naturally occurring hormone in your body turns against you? What do you do when that same hormone – melatonin – is a popular supplement you take to help you sleep? A University of Houston professor and his team of researchers may have some answers.

Self-organized Traffic Light Control System Could Improve Traffic Flow 95 Percent:

Traffic flows account for as much as one-third of global energy consumption. But unconventional changes in managing traffic flow could significantly reduce such waste and lower harmful CO2 emissions, says Dirk Helbing.

Genital Arousal Disorder Adversely Impacts Women’s Lives:

New research shows that women suffering from Persistent Genital Arousal Disorder (PGAD), a condition marked by unprovoked, intrusive and persistent sensations of genital arousal that are unrelieved by one or several orgasms, are likely to experience a variety of associated psychological conditions. Women who have this rare and often distressing condition often experience related depression, anxiety, panic attacks and frequently show a past history of sexual victimization.

Using Neural Signals To Predict Sensory Decisions:

The rodent whisker sensory system is particularly intriguing because it is “active”: the animal generates sensory signals by palpating objects through self-controlled whisker motion (just as we move our fingertips along surfaces to measure their tactile features).

Delay In Autumn Color Caused By Increased Carbon Dioxide Not Global Warming:

The delay in autumnal leaf coloration and leaf fall in trees is caused by rising levels of carbon dioxide (CO2) in the atmosphere and not by increased global temperatures, suggests a new study by researchers at the University of Southampton.

Zeroing In On Cellular Machinery That Enables Neurons To Fire:

If you ever had a set of Micronauts — toy robots with removable body parts — you probably had fun swapping their heads, imagining how it would affect their behavior. Scientists supported by the National Institutes of Health have been performing similar experiments on ion channels — pores in our nerve cells — to sort out the channels’ key functional parts.

Mud, Mud, Glorious Mud?:

Mother bats know exactly what’s good for them and their young: During pregnancy and lactation female bats are in great need of minerals. Dr. Christian Voigt from the Leibniz Institute for Zoo and Wildlife Research and colleagues found out how fruit-eating bats in the Ecuadorian rainforest cover their mineral requirements.

Trumpeter Swans Re-established In Ontario, Canada:

Originally native to Ontario, the trumpeter swan disappeared from Eastern Canada early in the 20th century. Restoration efforts were initiated in the early 1980s to reintroduce the trumpeter swan to its former range. Through conservation efforts the Ontario population has reached 1000, with at least 131 breeding pairs, and the future looks bright.

Your Homework: come up with a set of experiments that can be published in a single paper that can reasonably cite all the above studies.

How Poisonous Mushrooms Cook Up Toxins:

Alpha-amanitin is the poison of the death cap mushroom, Amanita phalloides. The Michigan State University plant biology research associate was looking for a big gene that makes a big enzyme that produces alpha-amanitin, since that’s how other fungi produce similar compounds. But after years of defeat, she and her team called in the big guns — new technology that sequences DNA about as fast as a death cap mushroom can kill. The results: The discovery of remarkably small genes that produce the toxin — a unique pathway previously unknown in fungi.

Brain Matures A Few Years Late In ADHD, But Follows Normal Pattern:

In youth with attention deficit hyperactivity disorder (ADHD), the brain matures in a normal pattern but is delayed three years in some regions, on average, compared to youth without the disorder, an imaging study by researchers at the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH) has revealed. The delay in ADHD was most prominent in regions at the front of the brain’s outer mantle (cortex), important for the ability to control thinking, attention and planning. Otherwise, both groups showed a similar back-to-front wave of brain maturation with different areas peaking in thickness at different times.

Tool-wielding Chimps Provide A Glimpse Of Early Human Behavior:

Chimpanzees inhabiting a harsh savanna environment and using bark and stick tools to exploit an underground food resource are giving scientists new insights to the behaviors of the earliest hominids who, millions of years ago, left the African forests to range the same kinds of environments and possibly utilize the same foods.

Tiny Fish Can Yield Big Clues To Delaware River Health:

Where have all the bridle shiner gone? That’s the mystery The Academy of Natural Sciences’ fish scientists are trying to answer, and the outcome will shed light on the environmental health of the Upper Delaware River.

Changing Environment Organizes Genetic Structure:

What is the fundamental creative force behind life on Earth? It’s a question that has vexed mankind for millennia, and thanks to theory and almost a year’s worth of number-crunching on a supercomputer, Rice University physicist and bioengineer Michael Deem thinks he has the answer: A changing environment may organize the structure of genetic information itself.

ECGC In Green Tea Is Powerful Medicine Against Severe Sepsis, Lab Study Suggests:

A major component of green tea could prove the perfect elixir for severe sepsis, an abnormal immune system response to a bacterial infection. In a new laboratory study, Haichao Wang, PhD, of The Feinstein Institute for Medical Research, and his colleagues have been studying the therapeutic powers of dozens of Chinese herbal compounds in reversing a fatal immune response that kills 225,000 Americans every year. They found that an ingredient in green tea rescued mice from lethal sepsis — and the findings could pave the way to clinical trials in patients.

How Global Is The Global Biodiversity Information Facility?:

Biologists and computer scientists have appealed for more information on the world’s biodiversity to be stored digitally so it may better be used to understand the impact of climate change on the Earth’s flora and fauna.

‘Time-sharing’ Tropical Birds Key To Evolutionary Mystery:

Whereas most birds are sole proprietors of their nests, some tropical species “time share” together – a discovery that helps clear up a 150-year-old evolutionary mystery, says Biology professor Vicki Friesen.

There are 27 brand-new articles, just uploaded on PLoS ONE. Here are a couple of titles that drew my immediate attention:
Maternal Enrichment during Pregnancy Accelerates Retinal Development of the Fetus:

Although much is known about the harmful effects parental stress has on offspring, little is understood about how enriching a mother’s environment affects fetal development. In this paper, the authors experiment on developing rat embryos and find that an enriched environment speeds up the development of the nervous system. The results suggest that development of the visual system is sensitive to environmental stimulation during prenatal life.

Prior Exposure to Uninfected Mosquitoes Enhances Mortality in Naturally-Transmitted West Nile Virus Infection:

West Nile Virus has the potential to cause serious disease in humans; the virus is spread by infected mosquitoes and typically infection either results in no symptoms or in mild feverish symptoms. In this study, Higgs and colleagues found that mice that had already been exposed to the saliva from uninfected mosquitoes were subsequently more likely to die upon being infected with West Nile Virus. These findings suggest that prior exposure to mosquito saliva could potentially result in a worse outcome from West Nile Virus infection.

Gene Expression in Human Hippocampus from Cocaine Abusers Identifies Genes which Regulate Extracellular Matrix Remodeling:

People who have abused drugs in the past find it hard to avoid relapse because they remember the euphoria linked to previous drug use. In order to see if past drug abuse is associated with molecular changes in the brain, the researchers here carried out microarray analysis of samples of the hippocampus from individuals addicted to cocaine, and from control individuals. The microarray data identifies a number of genes which are up- or down-regulated in response to cocaine exposure.

Incidence and Tracking of Escherichia coli O157:H7 in a Major Produce Production Region in California:

Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995-2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human illness.

Different Neurophysiological Mechanisms Underlying Word and Rule Extraction from Speech:

The initial process of identifying words from spoken language and the detection of more subtle regularities underlying their structure are mandatory processes for language acquisition. Little is known about the cognitive mechanisms that allow us to extract these two types of information and their specific time-course of acquisition following initial contact with a new language. We report time-related electrophysiological changes that occurred while participants learned an artificial language. These changes strongly correlated with the discovery of the structural rules embedded in the words. These changes were clearly different from those related to word learning and occurred during the first minutes of exposition. There is a functional distinction in the nature of the electrophysiological signals during acquisition: an increase in negativity (N400) in the central electrodes is related to word-learning and development of a frontal positivity (P2) is related to rule-learning. In addition, the results of an online implicit and a post-learning test indicate that, once the rules of the language have been acquired, new words following the rule are processed as words of the language. By contrast, new words violating the rule induce syntax-related electrophysiological responses when inserted online in the stream (an early frontal negativity followed by a late posterior positivity) and clear lexical effects when presented in isolation (N400 modulation). The present study provides direct evidence suggesting that the mechanisms to extract words and structural dependencies from continuous speech are functionally segregated. When these mechanisms are engaged, the electrophysiological marker associated with rule-learning appears very quickly, during the earliest phases of exposition to a new language.

As always, look around, read, rate, comment, annotate and send trackbacks…