This week in animal research 04/11/16
Protein speeds spinal repair in zebrafish
Mammals are not capable of regenerating complex nervous tissue after a severe spinal cord injury, which can often be fatal or cause paralysis.
But zebrafish - a small, tropical freshwater fish native to South East Asia - have the remarkable ability to speedily regenerate their nervous tissue.
Now researchers have identified a protein in the zebrafish that may rapidly boost the healing of major spinal cord injuries in humans.
Intestinal cells “remodel” in response to a fatty meal
“When we eat fatty foods, our body’s response is coordinated between our digestive organs, our nervous system, and the microbes living in our gut,” explained Farber. “Our research used zebrafish to focus on one aspect of this system—how the enterocyte cells inside our intestines respond to a high-fat meal.”
Their findings are published in the Journal of Biological Chemistry.
A rare species of frog which startles predators by flashing its bright orange groin has been discovered in swampland on Australia's east coast.
Not much bigger than a human fingertip, Mahony's Toadlet has a distinctive marbled underbelly.
Watch a video clip here:
How the chipmunk earned its stripes
Scientists have found the evolutionary gene change responsible for the distinctive markings of both the chipmunk and an African mouse.
The stripes may have helped the animals hide from daytime predators with keen eye sight, such as birds, they say.
Prof Hopi Hoekstra, of Harvard University, US, who led the research, said: "What these two rodents have in common is that they are both diurnal [active during daylight], when one could imagine stripes could be more valuable than if they were nocturnal.
Genetic Analysis Identifies (some) Proteins Controlling Sleep in Mice
Newly identified, a mutant mouse, named Sleepy, with an extended sleep time. This type was shown to carry a mutation in the Sik3 gene, which encodes an enzyme (SIK3) expressed in neurons of the brain that controls other proteins.
“We noticed that Sleepy mutants showed an exaggerated response to sleep deprivation,” first author Hiromasa Funato says. “Examining the brains of sleep-deprived mice revealed changes in the phosphorylation of amino acids within the SIK3 protein. These changes were disturbed by the Sik3 mutation in Sleepy mice, which is why they have an increased sleep need.”
A second sleep phenotype was identified with a shortened and unstable REM sleep period. “This mutant pedigree, named Dreamless, carries a mutation in the Nalcn gene, which encodes an ion channel thought to control neuronal excitability,” coauthor Chika Miyoshi says.
The article, “Forward-genetics analysis of sleep in randomly mutagenized mice” was published in Nature at DOI:10.1038/nature20142
Food allergies reversed in mice
Here’s how the technique works:
• The key component of this research is dendritic cells, which serve as the gate-keepers of the immune system and are present in tissues in contact with the external environment, such as the skin and the inner lining of the nose, lungs, stomach and intestines.
• Gordon’s pioneering treatment involves producing dendritic cells in a test tube and then exposing them to a unique mix of proteins, a vitamin A-related acid naturally occurring in the human gut, and to the allergen, in this case, peanut or ovalbumin (egg white protein). The modified dendritic cells are then reintroduced into the mouse.
• Using this technique, the researchers were able to nearly eliminate the allergic reaction by converting allergen-sensitive immune cells into cells that mimic the response seen in healthy, non-allergic individuals.
The treatment reduced the observed symptoms of anaphylaxis, and lowered other key protein markers in the allergic response by up to 90 per cent.
75th Anniversary of first patient treated with penicillin
Today marks the 75th anniversary of the first penicillin treatment. While Fleming made his original discovery in 1928, it was not until 1941 that a refined version was tested on a patient in Oxford. This patient trial was a result of work by researchers, including Nobel Prize Laureates Howard Florey and Ernst Chain, who developed modern penicillin thanks, in part, to work done in mice.
Radiation gives mice Alzheimer’s effects
Long term exposure to radiation appears to have effects on mice that are similar to Alzheimer's. Mice were exposed to 1 or 20 mGray of radiation over the period of 300 days. This resulted in molecular changes in the hippocampus part of the brain - an area involved with memories.
Zika may affect male reproduction system
A mouse study conducted at the Washington University in St. Louis suggests that Zika virus can permanently damage the male reproductive system. Results suggest that contracting Zika virus can cause shrunken testicles and lower levels of sex hormone. Mice tested three weeks after being injected with Zika were shown to have testes one tenth the size of normal.
Naturally occurring compound extends mice lives
A compound called NMN, which can be found naturally in foods like Cabbage and Edamame, has showed beneficial effects when given to mice. Mice given the compound showed a boosted level of NAD, a protein which is believed to play a role in the ageing process. Mice who took the compound had a longer lifespan than the control group.