Τρίτη, 1 Ιουλίου 2014

ScienceDaily: Top Environment News

ScienceDaily: Top Environment News

It's a girl! Gene silencing technology alters sex of prawns

Posted: 30 Jun 2014 04:34 PM PDT

Scientists have developed a novel method for generating single-sex populations of prawns. This could be used to boost the productivity of aquaculture farms and even as a biocontrol measure against invasive species and pests.

DNA analysis reveals that queen bumblebees disperse far from their birthplace before setting up home

Posted: 30 Jun 2014 04:33 PM PDT

Researchers are closer to understanding patterns of family relatedness and genetic diversity in bumblebees. The findings could help farmers, land managers and policy makers develop more effective conservation schemes for these essential pollinators.

Ancient Arctic sharks tolerated brackish water 50 million years ago

Posted: 30 Jun 2014 01:43 PM PDT

Sharks were a tolerant bunch some 50 million years ago, cruising an Arctic Ocean that contained about the same percentage of freshwater as Louisiana's Lake Ponchatrain does today, says a new study. The study indicates the Eocene Arctic sand tiger shark, a member of the lamniform group of sharks that includes today's great white, thresher and mako sharks, was thriving in the brackish water of the western Arctic Ocean back then. In contrast, modern sand tiger sharks living today in the Atlantic Ocean are very intolerant of low salinity, requiring three times the saltiness of the Eocene sharks in order to survive.

All the world's oceans have plastic debris on their surface

Posted: 30 Jun 2014 01:42 PM PDT

The Malaspina Expedition, led by the Spanish National Research Council, has demonstrated that there are five large accumulations of plastic debris in the open ocean that match with the five major twists of oceanic surface water circulation. In addition to the known accumulation of plastic waste in the North Pacific, there are similar accumulations in the central North Atlantic, the South Pacific, the South Atlantic and the Indian Ocean.

Ancient baby boom holds a lesson in over-population

Posted: 30 Jun 2014 01:41 PM PDT

Researchers have sketched out one of the greatest baby booms in North American history, a centuries-long 'growth blip' among southwestern Native Americans between 500 to 1300 A.D. It was a time when the early features of civilization -- including farming and food storage -- had matured to where birth rates likely 'exceeded the highest in the world today,' the researchers write. A crash followed, offering a warning sign to the modern world about the dangers of overpopulation.

Body odor reveals malarial infection

Posted: 30 Jun 2014 01:40 PM PDT

An infection with malaria pathogens changes the scent of infected mice, making those infected more attractive to mosquitoes, according to a new study. Researchers show that whether mosquitoes find the right victim to bite is not left to chance by the pathogen. Instead, the plasmodium parasite appears to manipulate its host by changing the characteristics of the infected individual's body odour, which makes the carrier more attractive to hungry mosquitoes.

New method to grow zebrafish embryonic stem cells

Posted: 30 Jun 2014 01:40 PM PDT

Zebrafish, a model organism that plays an important role in biological research and the discovery and development of new drugs and cell-based therapies, can form embryonic stem cells (ESCs). For the first time, researchers report the ability to maintain zebrafish-derived ESCs for more than two years without the need to grow them on a feeder cell layer.

Study of animal urination could lead to better-engineered products

Posted: 30 Jun 2014 01:40 PM PDT

A new study investigated how quickly 32 animals urinate. It turns out that it's all about the same. Even though an elephant's bladder is 3,600 times larger than a cat's (18 liters vs. 5 milliliters), both animals relieve themselves in about 20 seconds.

Evolution of life’s operating system revealed in detail

Posted: 30 Jun 2014 01:40 PM PDT

The evolution of the ribosome, a large molecular structure found in the cells of all species, has been revealed in unprecedented detail in a new study.

In human evolution, changes in skin's barrier set northern Europeans apart

Posted: 30 Jun 2014 11:08 AM PDT

The popular idea that northern Europeans developed light skin to absorb more UV light so they could make more vitamin D -- vital for healthy bones and immune function -- is questioned by researchers in a new study. Ramping up the skin's capacity to capture UV light to make vitamin D is indeed important, however, researchers concluded in their study that changes in the skin's function as a barrier to the elements made a greater contribution than alterations in skin pigment in the ability of northern Europeans to make vitamin D.

Key component of cell division comes to light

Posted: 30 Jun 2014 09:44 AM PDT

The in vivo visualization and monitoring of the starting points of microtubules -- filaments responsible for organizing the mitotic spindle -- provides novel insight into the dynamic architecture of this structure. The findings will also contribute to understanding how the mitotic spindle is perturbed by drugs that target microtubules and that are used in chemotherapy.

Forelimb bone data predicts predator style

Posted: 30 Jun 2014 09:44 AM PDT

In their quest to understand what kind of hunter the extinct marsupial Thylacine was, two paleobiologists built a dataset of forelimb bone measurements that predict the predation style of a wide variety of carnivorous mammals.

Bacterial colonies evolve amazing diversity

Posted: 30 Jun 2014 09:44 AM PDT

Like human societies -- think New York City -- bacterial colonies have immense diversity among their inhabitants, often generated in the absence of specific selection pressures, according to a new article.

Artificial enzyme mimics natural detoxification mechanism in liver cells

Posted: 30 Jun 2014 08:41 AM PDT

Molybdenum trioxide nanoparticles oxidize sulfite to sulfate in liver cells in analogy to the enzyme sulfite oxidase, researchers have found. The functionalized Molybdenum trioxide nanoparticles can cross the cellular membrane and accumulate at the mitochondria, where they can recover the activity of sulfite oxidase.

Progress in fight against tuberculosis

Posted: 30 Jun 2014 08:41 AM PDT

Leading immunologists express confidence that clear advances in the fight against tuberculosis are within reach. "The old BCG vaccine against tuberculosis primarily activates only helper cells. The trick with our new vaccine is to additionally activate the killer cells, which enables us to trigger an improved immune system response," one expert says. In addition to research into vaccines, innovative treatments are also being investigated which attempt to entice the bacteria out of their macrophage hiding places.

Cellular team players: enzymes work with co-trainer, scientists show

Posted: 30 Jun 2014 08:41 AM PDT

Many enzymes work only with a co-trainer, of sorts. Scientists show what this kind of cooperation looks like in detail using a novel methodology applied to the heat shock protein Hsp90.

Breathe easy and don't scratch this Fourth of July

Posted: 30 Jun 2014 08:34 AM PDT

Activities surrounding the 4th of July can create health hazards for those who suffer from allergies and asthma. Smoke from fireworks can make it hard for those with asthma to breathe, and certain fresh fruits and vegetables can create an allergy-like reaction for people with hay fever.

Green spaces in cities may increase erosion of building materials such as stone, concrete and steel

Posted: 30 Jun 2014 07:31 AM PDT

Green spaces in towns and cities need extra consideration as they may be damaging buildings in the area, according to new research. When organic chemicals from trees and vegetation mix with air pollutants the resulting corrosive gas can increase the erosion of building materials, including stone, concrete and steel.

A first: Scientists show bacteria can evolve biological timer to survive antibiotics

Posted: 30 Jun 2014 07:31 AM PDT

When exposed to repeated cycles of antibiotics, within days bacteria can evolve a new adaptation, by remaining dormant for the treatment period to survive antibiotic stress. The results show for the first time that bacteria can develop a biological timer to survive antibiotic exposure. With this new understanding, scientists could develop new approaches for slowing the evolution of antibiotic resistance.

Water samples teeming with information: Emerging techniques for environmental monitoring

Posted: 30 Jun 2014 06:48 AM PDT

Setting effective conservation policies requires near real-time knowledge of environmental conditions. Scientists propose using genetic techniques as a low-cost, quick way to collect such data.

Whaling logbooks could hold key to retreating Arctic ice fronts

Posted: 30 Jun 2014 06:46 AM PDT

Ice fronts from the early 19th century were far more advanced around the Arctic than they are today, researchers analysing whalers' log books from this time have discovered.

Green planning needed to maintain city buildings

Posted: 30 Jun 2014 06:45 AM PDT

Green spaces in towns and cities need extra consideration as they may be damaging buildings in the area, according to new research. When organic chemicals from trees and vegetation mix with air pollutants the resulting corrosive gas can increase the erosion of building materials, including stone, concrete and steel, researchers say.

Almonds reduce the risk of heart disease, research shows

Posted: 30 Jun 2014 06:45 AM PDT

Eating almonds can reduce the risk of heart disease by keeping blood vessels healthy, research has shown. Research found that they significantly increase the amount of antioxidants in the blood stream, reduce blood pressure and improve blood flow. These findings add weight to the theory that Mediterranean diets with lots of nuts have big health benefits.

More carbohydrates make trees more resistant to drought

Posted: 30 Jun 2014 06:36 AM PDT

How well tropical trees weather periods of drought depends on the carbohydrates stored, as revealed by a novel experiment conducted by an international team of researchers. The findings are extremely important for assessing the resistance of tropical forests to climate change and reforestation.

Climate change in the North Sea: Long-term studies reveal drastic changes in the marine fauna

Posted: 30 Jun 2014 06:36 AM PDT

Long-term studies have revealed obvious changes in the North Sea's biota. Studies during the past twenty years indicate that southern species increasingly expand northward. The Atlantic cod is drawn to cooler regions, while crustaceans from southern areas spread ever farther into the North Sea. The effects of the climate change can be clearly felt on the German sea coasts, as well.

Algae as chemical raw materials

Posted: 30 Jun 2014 06:36 AM PDT

Chemists and biologists have succeeded in transforming algae oil into high-quality chemical raw materials via so-called isomerizing alkoxycarbonylation. This provides the foundation for the use of algae as a basic chemical component for a broad spectrum of materials and products, beyond the use of algae as a substitute for crude oil.

Common herbal supplement can cause dangerous interactions with prescription drugs

Posted: 30 Jun 2014 06:33 AM PDT

St. John's wort, the leading complementary and alternative treatment for depression in the United States, can be dangerous when taken with many commonly prescribed drugs, according to a study. The researchers reported that the herbal supplement can reduce the concentration of numerous drugs in the body, including oral contraceptive, blood thinners, cancer chemotherapy and blood pressure medications, resulting in impaired effectiveness and treatment failure.

Evaluation of quantitative microRNA expression platforms in the microRNA quality control (miRQC) study

Posted: 29 Jun 2014 11:17 AM PDT

New research has been published that helps researchers to assess the technical performance of laboratory methods to study small RNA molecules. RNA (ribonucleic acid) is the chemical origin of life. Detection and quantification of such small RNAs is challenging and requires state of the art lab instrumentation that enables reliable microRNA quantification.

Reconstructing the life history of a single cell: Cell's unique mutations used to trace history back to its origins in the embryo

Posted: 29 Jun 2014 11:17 AM PDT

Researchers have developed new methods to trace the life history of individual cells back to their origins in the fertilised egg. By looking at the copy of the human genome present in healthy cells, they were able to build a picture of each cell's development from the early embryo on its journey to become part of an adult organ. 

Marine bacteria are natural source of chemical fire retardants

Posted: 29 Jun 2014 11:17 AM PDT

Researchers have discovered a widely distributed group of marine bacteria that produce compounds nearly identical to toxic human-made fire retardants.

How deadly lassa virus infects cells

Posted: 27 Jun 2014 08:31 AM PDT

The Lassa virus, endemic to West Africa, uses an unexpected two-step process to enter cells, research has shown. The results suggest that the mechanism by which Lassa virus causes infection is more complicated than previously known, and could lead to new approaches for preventing the disease.

Slaying bacteria with their own weapons

Posted: 26 Jun 2014 01:08 PM PDT

A novel antibiotic delivery system would exploit small molecules called siderophores that bacteria secrete to scavenge for iron in their environments. Each bacterium has its own system of siderophores, which it pumps across its cell membrane before releasing the iron the siderophores hold. If an antibiotic were linked to one of these scavenger molecules, it would be converted into a tiny Trojan horse that would smuggle antibiotics inside a bacterium's cell membrane.

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