January 21, 2011, 8:28 PM CT

Biological Clock Ticks Slower for Some Female Birds

In birds as in humans, female fertility declines with age.

But some female birds can slow the ticking of their biological clocks by choosing the right mates, as per results of a study published online last week in the journal Oikos

Female birds become progressively less fertile as age takes its toll, says biologist Josh Auld of the National Evolutionary Synthesis Center in Durham, North Carolina, and co-author of the Oikos paper.

Older females lay fewer eggs, and they lay them later in the season--at a time when less food is available for their chicks.

But despite abundant evidence of fading fertility in females, researchers knew little about the role played by their mates. "The thought was that males didn't matter," Auld says.

But they do.

"These results are very unexpected, and one cannot help but wonder if they apply to vertebrates more generally," says Saran Twombly, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.

"The work highlights the power of data synthesis to reveal patterns that arise only by combining lots of data to address new questions," says Twombly.

"It also emphasizes the need to integrate physiology, behavior, and other biological disciplines to understand what organisms do and how they interact in the wild."......... Posted by: Kelly      Read more         Source

January 21, 2011, 8:26 PM CT

Amoebae Pack a Lunch Before They Travel

Some amoebae do what a number of people do. Before they travel, they pack a lunch.

In results of a study reported today in the journal Nature, evolutionary biologists Joan Strassmann and David Queller of Rice University show that long-studied social amoebae Dictyostellum discoideum (usually known as slime molds) increase their odds of survival through a rudimentary form of agriculture.

Research by main author Debra Brock, a graduate student at Rice, observed that some amoebae sequester their food--particular strains of bacteria--for later use.

"We now know that primitively social slime molds have genetic variation in their ability to farm beneficial bacteria as a food source," says George Gilchrist, program director in the National Science Foundation's Division of Environmental Biology, which funded the research. "But the catch is that with the benefits of a portable food source, comes the cost of harboring harmful bacteria.".

After these "farmer" amoebae aggregate into a slug, they migrate in search of nourishment--and form a fruiting body, or a stalk of dead amoebae topped by a sorus, a structure containing fertile spores. Then they release the bacteria-containing spores to the environment as feedstock for continued growth......... Posted by: Janet      Read more         Source

January 16, 2011, 10:11 PM CT

New software quantifies leaf venation networks

Plant biologists are facing pressure to quantify the response of plants to changing environments and to breed plants that can respond to such changes. One method of monitoring the response of plants to different environments is by studying their vein network patterns. These networks impact whole plant photosynthesis and the mechanical properties of leaves, and vary between species that have evolved or have been bred under different environmental conditions.

To help address the challenge of how to quickly examine a large quantity of leaves, scientists at the Georgia Institute of Technology have developed a user-assisted software tool that extracts macroscopic vein structures directly from leaf images.

"The software can be used to help identify genes responsible for key leaf venation network traits and to test ecological and evolutionary hypotheses regarding the structure and function of leaf venation networks," said Joshua Weitz, an assistant professor in the Georgia Tech School of Biology.

The program, called Leaf Extraction and Analysis Framework Graphical User Interface (LEAF GUI), enables researchers and breeders to measure the properties of thousands of veins much more quickly than manual image analysis tools.

Details of the LEAF GUI software program were reported in the "Breakthrough Technologies" section of the recent issue of the journal Plant Physiology Development of the software, which is available for download at www.leafgui.org, was supported by the Defense Advanced Research Projects Agency (DARPA) and the Burroughs Welcome Fund......... Posted by: Erica      Read more         Source

January 16, 2011, 10:10 PM CT

What is life?

Biologists have been unable to agree on a definition of the complex phenomenon known as "life." In a special collection of essays in Astrobiology, a peer-evaluated journal from Mary Ann Liebert, Inc., leaders in the fields of philosophy, science, and molecular evolution present a variety of perspectives on defining life. Tables of content and a free sample issue are available online.

Why is a definition of life so important yet so elusive? As David Deamer, Guest Editor and Research Professor of Biomolecular Engineering, University of California, Santa Cruz, writes in his Introduction, a definition is needed to help determine what is and is not life as researchers begin to develop artificial life forms in the laboratory and, in the future, dispatch exploratory rovers that investigate what appear to be life forms on other planets.

Mark Bedau, Reed College (Portland, OR) and the University of Southern Denmark (Odense), relies on the Program-Metabolism-Container (PMC) model to define minimal chemical life. He supports his belief that this integrated triad of chemical systems is all that is needed for a living organism to maintain its existence, grow, reproduce, and evolve, in the essay entitled, "An Aristotelian Account of Minimal Chemical Life".

Antonio Lazcano, National Autonomous University of Mexico, and his colleagues present an historical perspective of the a number of definitions of life put forth over the years and why they have been unsatisfactory, in the essay, "The Definition of Life: A Brief History of an Elusive Scientific Endeavor."........ Posted by: Janet      Read more         Source

January 16, 2011, 10:02 PM CT

More than 31 freshwater species have moved

Galician scientists have studied the evolution in the introduction of non-native fresh water species in Galicia over the past century, and have compared this with the rest of the Iberian Peninsula. The results show that 31 exotic aquatic species out of the 88 recorded for the entire Iberian Peninsula have become established in the region over the past century.

An analysis of the introduction of non-native species in Galicia and the Iberian Peninsula carried out by scientists from the University of Santiago de Compostela (USC) and the University of Coru�a (UDC) has shown not only the number of species introduced over the past 100 years, but also the periods during which the greatest number of new species appeared, and also current trends.

It has taken longer for exotic species to be introduced in Galicia than in the rest of the Iberian Peninsula. "While the species introduced in the Iberian Peninsula at the start of the 20th Century took between 80 and 90 years to be recorded in Galicia, this delay has been virtually negligible since the 1990s", Mar�a J. Servia, coordinator of the study and a researcher at the UDC, tells SINC.

As per Servia, species introduced in the Iberian Peninsula are now detected at "practically" the same time in Galicia. The data analysed show that 1995 marked a turning point, coinciding with the approval of the Schengen Treaty, which opened up the borders of European countries to the free movement of people and goods. From this time on, the pace of introduction of new species in Galicia has been the same as for the rest of Spain......... Posted by: Kelly      Read more         Source

January 16, 2011, 9:51 PM CT

100-year-old spWhen avian pox hit Galapagos

A research team from across the United States and Ecuador has pinpointed 1898 as the year the avipoxvirus, or avian pox, hit the Galapagos Islands and started infecting its birds. This estimation is vital to understanding avian diseases that affect today's Galapagos birds. The scientists' paper on the subject, "110 Years of Avipoxvirus on the Galapagos Islands," will be published on January 13 in PLoS ONE, an international, open-access science publication.

The research team, led by Dr. Patricia Parker of the University of Missouri�St. Louis, examined 3,607 finches and mockingbirds collected in the Galapagos between 1898 and 1906 that are currently held at the California Academy of Sciences in San Francisco, along with 266 birds collected in 1891 and 1897 held at the Zoologische Staatssammlung in Munich, Gera number of. The researchers inspected the birds for skin lesions linked to avian pox infection and found 226 candidates dating from 1898 or later. For a small subset of these (59 specimens), the researchers took tissue samples for further pathological studies. In the end, a total of 21 specimens scored positive for avipoxvirus using histology (tissue examination under a microscope) and genotyping (screening for viral DNA).

"Without museum collections, work like this would never be possible," said Dr. Jack Dumbacher, Curator of Ornithology at the California Academy of Sciences. "Because museum specimens include detailed collection date and location data, they can be used to study not only a particular species, but also historical events and environmental conditions. Without this library of specimens, we might never have learned when or how this potentially devastating disease made its way to Darwin's famous islands"......... Posted by: Kelly      Read more         Source

January 16, 2011, 9:18 PM CT

Heavy metals and pesticides threaten

The Estero de Domingo Rubio wetland, located near the Marismas del Odiel Natural Area in the Huelva estuary, is regionally, nationally and internationally protected thanks to its ecological value. However, its tributary rivers and the R�a de Huelva estuary pump manmade pollutants into it, which could affect its water quality and ecosystem.

Industrial activity, accumulations of dangerous waste, the expansion of farming, and excessive extraction of sand and gravel for the construction industry are the leading threats to the Estero de Domingo Rubio wetland, the tidal system of which plays a "crucial" role in transporting and dispersing pollutants.

The wetland is "periodically flooded with high levels of dissolved elements such as copper (Cu), arsenic (As), cadmium (Cd), cobalt (Co), chrome (Cr), nickel (Ni) and zinc (Zn), which come from the water entering the estuary, which is affected by pollution from the mining industry", Cinta Barba-Brioso, co-author of the study and a researcher at the University of Seville (US), tells SINC.

The study, which has recently been reported in the Marine Pollution Bulletin, shows that the wetland's tidal channel also receives acid lixiviates (liquid pollutants) that come from the dumping of sulphurous waste, industrial waste outflow pipes, and abandoned chemical plants, which all contribute to its metallic "enrichment"......... Posted by: Erica      Read more         Source

January 16, 2011, 9:00 PM CT

Fisheries management makes coral reefs grow faster

An 18-year study of Kenya's coral reefs by the Wildlife Conservation Society and the University of California at Santa Cruz has observed that overfished reef systems have more sea urchins�organisms that in turn eat coral algae that build tropical reef systems.

By contrast, reef systems closed to fishing have fewer sea urchins�the result of predatory fish keeping urchins under control�and higher coral growth rates and more structure.

The paper appears in the December 2010 issue of the scientific journal Ecology The authors include Jennifer O'Leary of the University of California at Santa Cruz and Tim McClanahan of the Wildlife Conservation Society.

The authors observed that reefs with large numbers of grazing sea urchins reduced the abundance of crustose coralline algae, a species of algae that produce calcium carbonate. Coralline algae contribute to reef growth, specifically the kind of massive flat reefs that fringe most of the tropical reef systems of the world.

The study focused on two areas�one a fishery closure near the coastal city of Mombasa and another site with fished reefs. The scientists observed that sea urchins were the dominant grazer in the fished reefs, where the predators of sea urchins�triggerfish and wrasses�were largely absent. The absence of predators caused the sea urchins to proliferate and coralline algae to become rare......... Posted by: Kelly      Read more         Source

January 16, 2011, 8:56 PM CT

Green Super Rice is coming

Rice bred to perform well in the toughest conditions where the poorest farmers grow rice is a step away from reaching farmers thanks to a major project led by the Chinese Academy of Agricultural Sciences and the International Rice Research Institute (IRRI).

Green Super Rice is actually a mix of more than 250 different potential rice varieties and hybrids variously adapted to difficult growing conditions such as drought and low inputs, including no pesticide and less fertilizer, and with rapid establishment rates to out-compete weeds, thus reducing the need for herbicides. More types of Green Super Rice that combine a number of of these traits are in the pipeline.

As published in the latest issue of Rice Today, Green Super Rice is already in the hands of national agricultural agencies in key rice-growing countries for testing and development.

Green Super Rice is an example of what is needed as part of a "Greener Revolution," which is called for by rice researchers around the world and is one of the driving concepts behind the Global Rice Science Partnership (GRiSP) - a plan to improve international partnerships in rice research, its delivery, and impact that would also ensure that rice is grown in an environmentally sustainable way.

With the theme Rice for Future Generations, the 3rd International Rice Congress held in November last year was the perfect venue for the launch of GRiSP. Incredible sharing of rice research and ideas occurred, which Rice Today features in a suite of stories outlining some of the highlights and activities of the event that was attended by more than 1,900 people......... Posted by: Erica      Read more         Source

January 16, 2011, 8:47 PM CT

Choosing organic milk

Wetter, cooler summers can have a detrimental effect on the milk we drink, as per new research published by Newcastle University.

Scientists found milk collected during a especially poor UK summer and the following winter had significantly higher saturated fat content and far less beneficial fatty acids than in a more 'normal' year.

But they also discovered that switching to organic milk could help overcome these problems. Organic supermarket milk showed higher levels of nutritionally beneficial fatty acids compared with 'ordinary' milk regardless of the time of year or weather conditions.

The study, which is published in this month's Journal of Dairy Science (January 2011), leads on from prior research undertaken nearly three years ago which looked at the difference between organic and conventional milk at its source � on the farms.

"We wanted to check if what we found on farms also applies to milk available in the shops," said Gillian Butler, who led the study. "Surprisingly, the differences between organic and conventional milk were even more marked. Whereas on the farms the benefits of organic milk were proven in the summer but not the winter, in the supermarkets it is significantly better quality year round".

There was also greater consistency between organic suppliers, where the conventional milk brands were of variable quality......... Posted by: Kelly      Read more         Source