New skin test determines age of wild animals to help control nuisance animals

Posted by Biomechanism 

A new skin test can determine the age of wild animals while they are still alive, providing information needed to control population explosions among nuisance animals, according to a report here today at the 242nd National Meeting & Exposition of the American Chemical Society (ACS).

Tigers (and all the Order Carnivora which consists of all cats, dogs, bears, seals, weasels, stoats, pinnipeds, etc.) are descended from the family of marten-like woodland animals called the miacidae. These small omnivores evolved during the late Cretaceous period (toward the end of the age of the dinosaurs), about 70-65 million years ago.

ACS, the world largest scientific society with more than 163,000 members, is holding the meeting through Thursday at the Colorado Convention Center and downtown hotels. With 7,500 reports on new advances in science and more than 12,000 scientists and others expected in attendance, it will be one of 2011’s largest scientific gatherings.

Randal Stahl, Ph.D., said that the improved method will provide important information about the health and stability of herds, flocks and other populations of wild animals, which lack the established birthdates of prized cattle, horses, and many household pets.

“Determining the age of wild animals is important for a number of reasons,” Stahl explained. “We are in the midst of population explosions of some animals that have negative impacts on people, property and other animals. Wildlife management programs have been established to cope with the situation. Some of these programs, for instance, seek to maintain healthy numbers of breeding pairs. The new skin test will help us tell how many animals in a wild population are of breeding age.”

Stahl is a scientist with the National Wildlife Research Center (NWRC) in Fort Collins, CO. The center is the research arm of the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services program.

The test detects pentosidine, a biomarker for so-called advanced glycation end products (AGEs), substances that form in the body as a result of aging; the amounts can indicate an animal’s age. Those substances also form in humans, and have been linked to a range of chronic disorders, including type 2 diabetes, cancer and Alzheimer’s disease.

Tests for AGEs already exist and have been used in both animals and humans. At the ACS meeting, Stahl and colleagues described development of a more sensitive version of the animal test. That test involves taking a biopsy, or sample, of the animal’s skin. In the past, scientists needed such a large skin sample — about the size of a postage stamp — that scientists usually could do the test only on dead animals. The new version of the test requires a skin sample only the size of a pea.

“We improved the sensitivity of the pentosidine test so we can detect very small amounts of it,” Stahl said. “The advance will enable scientists to capture a few individuals, take a small skin sample without harming the animal and then release it back into the wild. With this approach, we can sample a population repeatedly over time without having an effect on the size of the population.”

Stahl’s group is currently studying double-crested cormorants, large fish-eating birds that have become a nuisance due to population explosions. Federal and state agencies in the Great Lakes region, and other areas, are trying to manage cormorant populations to reduce the birds’ adverse impacts on vegetation, other water birds, private property, fish farming, sports fishing and risks of collisions with aircraft. Those efforts involve maintaining the number of breeding pairs of cormorants at environmentally healthy levels. And the new skin test will enable scientists to gauge the number of birds that are of breeding age.

Collaborating with the NWRC field station in Mississippi, the researchers also developed a technique of handling cormorants to obtain samples with little harm to the birds. They place a small hollow metal cylinder called a biopsy punch on the bird’s skin to remove the sample and then put an adhesive on the wound to prevent infection and promote healing, just like a Band-Aid. No anesthesia is needed.

Stahl plans to use the skin analysis method to study other wild populations, such as invasive species of snakes and lizards in Florida. And because of recent coyote attacks on humans in populated areas, such as the suburbs of New York City and in California, Stahl’s team also will use the method to determine the demographics of these urban coyote populations during management activities.

Scientists develop new technologies for understanding bacterial infections

Posted by Biomechanism 

“New approach for studying molecules within their natural environment.”

Understanding how bacteria infect cells is crucial to preventing countless human diseases. In a recent breakthrough, scientists from the University of Bristol have discovered a new approach for studying molecules within their natural environment, opening the door to understanding the complexity of how bacteria infect people.

this development has enabled the research team to correlate intricate, atomic level detail of UspA1 obtained by X-ray crystallography of isolated fragments of the protein with delicate and previously unobservable physical changes of the bacterial cell as it binds to and infects its target human cells.

The research, led by a team of biochemists, microbiologists and physicists and published in the Proceedings of the National Academy of Sciences (PNAS), provides an unprecedented level of detail of the consequences of a bacterium approaching another cell, directly in situ.

Until now, traditional approaches to understanding infection have focused on either studies of the cells involved or dissection of individual molecules present within the cells. Leo Brady, Professor of Biochemistry and Mumtaz Virji, Professor of Molecular Microbiology, who led the research, have developed a novel method for bridging these, until now, separate approaches.

The team studied the common bacterium Moraxella catarrhalis, which causes middle ear infections in young children, and is a major cause of morbidity in those with heart disease. For many years, scientists approached this problem from the molecular medicine approach — through isolating and studying proteins from the Moraxella cell surface that initiate infection.

From these detailed studies the team have been able to develop an overview of one of the key proteins, called UspA1. However, as with the vast majority of molecular medicine approaches, this model has been based on studies of the UspA1 protein in isolation, rather than in its natural setting on the bacterium surface. A common worry for many biomedical scientists is how such understanding translates into the reality of these tiny molecules when they are part of a much larger cell. Understanding the increased complexity of individual molecules within the cellular mêlée is crucial to understanding why many promising drugs fail to live up to expectations.

To begin bridging this gap in our understanding, Professors Brady and Virji teamed up with Dr Massimo Antognozzi from the University’s School of Physics, whose group have been developing a novel form of atomic force microscope, termed the lateral molecular force microscope (LMFM).

Together, they have evolved the design of the LMFM microscope to optimise its ability to measure biological phenomena such as changes in UspA1 directly at the Moraxella cell surface. The LMFM differs from more conventional atomic force microscopes in tapping samples (in this case, individual cells) against an extremely fine lever, equivalent to the stylus of a record player, rather than moving the lever as is usually the case. Fabrication of extremely thin but stiff cantilevers together with exceptionally fine motor movements and a specialised visualisation system have all been combined in the device to tremendous effect. The sensitivity achieved has been further enhanced by its location within the extremely low vibration environment provided within the University’s innovative Nanoscience and Quantum Information building. The result has been a machine that can measure exquisitely fine molecular changes and forces in individual molecules directly on a living cell surface.

In the Moraxella study, this development has enabled the research team to correlate intricate, atomic level detail of UspA1 obtained by X-ray crystallography of isolated fragments of the protein with delicate and previously unobservable physical changes of the bacterial cell as it binds to and infects its target human cells.

Professor Brady said: “The findings have triggered the development of a novel technology that promises to open up a new approach for studying molecular medicine. This breakthrough will undoubtedly prove equally useful for the study of many other biological processes directly within their cellular environment, something that has long been needed in molecular medicine.”

This combined study has enabled the researchers to observe the very first responses as a bacterium binds to a human cell, hence opening the door to understanding the complexity of infection processes.
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The UspA1 LMFM studies have been funded by the Wellcome Trust and the Biotechnology and Biological Sciences Research Council (BBSRC) and are published today [29 Aug] in the journal Proceedings of the National Academy of Sciences (PNAS).

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