Life & Non-humans

Climate Change Linked to Population Shifts Among Mammals

Scientists have shown, for the first time, that changes in a large-scale climate system can synchronize population fluctuations in multiple mammal species across a continent-scale region. The study, to be published in the 14 November 2002 issue of the journal Nature, compares long-term data on the climate system known as the North Atlantic Oscillation with long-term data from Greenland on the population dynamics of caribou and muskoxen, which are large mammals adapted to breeding in the Arctic.

Choreography, not molecular prepattern, creates vertebrate building blocks

In a study that combines state-of-the-art biological imaging with gene expression analysis, scientists at the California Institute of Technology have uncovered a fundamental insight into the way embryonic cells and tissue move about to form key structures along the vertebrate axis. The study, which could lead to a better understanding of human development, takes advantage of the accessibility of chick embryos to embryonic manipulation. The study enters on segments known as somites, which form along either side of the future spinal cord of an embryo. Somites give rise to mature structures such as ribs, individual vertebrae, and even skin. The key role of somite segmentation in the patterning of the nervous system and the vertebral column has been long known. But the question of precisely how an individual somite buds off from a block of tissue in a pattern that is repeated all along the animal’s torso, from head to tail, is poorly understood.

Drug Averts Parkinson’s in Fruit Flies, New Approaches Possible in Humans

Scientists have averted the onset of neurodegenerative disease in fruit flies by administering medication to flies genetically predisposed to a disorder akin to Parkinson’s disease. The result suggests a new approach to the treatment of human disorders including Parkinson’s and Alzheimer’s diseases. Parkinson’s disease is the second most common human neurodegenerative disorder, characterized by tremors, postural rigidity and progressive deterioration of dopaminergic neurons in specific areas of the brain. Despite the evolutionary gulf separating humans and fruit flies, neurotoxicity unfolds in a similar manner in both species.

Emperor Penguin Colony Struggling With Iceberg Blockade

The movements of two gigantic Antarctic icebergs appear to have dramatically reduced the number of Emperor penguins living and breeding in a colony at Cape Crozier, according to two researchers who visited the site last month. The colony is one of the first ever visited by human beings early in the 20th century. “It’s certain that the number of breeding birds is way down” from previous years, said Gerald Kooyman, a National Science Foundation-funded researcher at the Scripps Institution of Oceanography in La Jolla, Calif.

Cholestrol Drug Could Lead to New Therapy for Multiple Sclerosis

While cautioning that their findings still must be evaluated in humans, University of California, San Francisco and Stanford University Medical Center researchers report that the cholesterol-lowering drug atorvastatin (Lipitor) significantly improved, prevented relapses or reversed paralysis in mice with an experimental disease that closely resembles multiple sclerosis. The study, reported in the November 7 issue of Nature, was conducted in mice with experimental autoimmune encephalomyelitis (EAE), the standard animal model for multiple sclerosis.

Researchers Say Tiny Phytoplankton Plays Large Role in Earth’s Climate

The ecological importance of phytoplankton, microscopic plants that free-float through the world’s oceans, is well known. Among their key roles, the one-celled organisms are the major source of sustenance for animal life in the seas. Now, researchers at Scripps Institution of Oceanography in San Diego say that phytoplankton exert a significant and previously uncalculated influence on Earth’s climate.

European Seal Plague May Threaten Population Survival

Time to find zee cureThe 2002 outbreak of phocine distemper virus, or PDV, in European harbor seals may reduce the population by more than half and that future outbreaks with similar characteristics would significantly increase the risk of population declines. Their findings are the first epidemiological data reported on the 2002 outbreak, which is still underway, and may help predict the recurrence of the outbreaks and the impact on the long-term growth and survival of the European harbor seal population.

E. coli, Listeria Take On Melanoma

Listeria and certain strains of E. coli are the scourge of picnics, but researchers at Harvard Medical School and London’s Hammersmith Hospital show in the November Gene Therapy that combining bacterial components of these bad bugs can create a powerful vector against melanoma challenged mice.

New Tool for Studying Animal Models of Neurological, Psychiatric Diseases

U.S. government scientists have demonstrated that a miniature positron emission tomography (PET) scanner, known as microPET, and the chemical markers used in traditional PET scanning are sensitive enough to pick up subtle differences in neurochemistry between known genetic variants of mice. This “proof-of-principle” experiment “opens up a whole new, non-invasive way to study and follow transgenic or genetically engineered strains of mice that serve as animal models for human neurological diseases, such as Parkinson’s and Alzheimer’s disease or psychiatric diseases such as substance abuse, depression, and anxiety disorders,” said Panayotis (Peter) Thanos, lead author of the study.

Animal studies confirm hormone replacement can improve learning

For estrogen to enhance learning and memory, nerve cells in the brain called cholinergic neurons are essential to the process, suggest animal studies performed by researchers from the University of Pittsburgh School of Pharmacy. “Estrogen replacement in postmenopausal women has important effects on mood and cognition. This research was focused on trying to understand what estrogen does in the brain to reduce the effects on brain aging and cognitive decline,” said Robert Gibbs, associate professor of pharmaceutical sciences at the University of Pittsburgh School of Pharmacy.

Hibernating Squirrels Provide Clues for Stroke, Parkinson’s

A compound that enables squirrels to hibernate may one day help minimize brain damage that results from stroke. In an animal model for stroke, delta opioid peptide reduced by as much as 75 percent the damage to the brain’s striatum, the deeper region of the brain and a major target for strokes, according to researchers. In fact, evidence suggests that the compound, which puts cells in a temporary state of suspended animation, may help protect brain cells from the ravages of Parkinson’s disease as well.

Firefly Light Illuminates Course of Herpes Infection in Mice

Researchers are using a herpes virus that produces a firefly enzyme to illuminate the virus’s course of infection in mice and to help monitor the infection’s response to therapy. “This study demonstrates the feasibility of monitoring microbial infections in living animals in real time,” says study leader David A. Leib. “The technique enables us to follow an infection over time as it progresses and resolves, and we can do this repeatedly using the same animal.”

Gut Bacteria Interact with Intestine to Regulate Blood Supply

Bacteria aren’t always bad. In fact, they can be extremely helpful partners. According to research at Washington University School of Medicine in St. Louis, microbes found naturally in the mouse and human gut interact with intestinal cells, called Paneth cells, to promote the development of blood vessels in the intestinal lining. “This study provides insights into the mutually beneficial partnerships forged between mammals and their native microbes,” says the principal investigator. “These symbiotic relationships probably are most important in the gut, which contains the largest and most complex collection of bacteria.”