Image of common model organisms from European Molecular Biology Laboratory (EMBL).

A recent article posted in the BBC News provided a good explanation of why scientists commonly study these organisms as models for human diseases and conditions. Model organisms are chosen because their physiology is similar to other animals, including humans, in addition to other reasons:

Visit the BBC News to see why researchers most often use flies, fish, mice and worms to understand the mechanisms of disease and health.

Did you know that ~70% of the genes in a fruit fly are homologous to human genes?  Zebrafish have genes that are homologous to those involved in ~75% of genetic-related human diseases. 

Top Image: EMBL, Explore Model Organisms

Image source: AKIKO KUMAGAI & ATSUSHI MIYAWAKI as posted in Scientific American

Dr. Miyawaki from the RIKEN Brain Science Institute in Wako, Japan and colleagues have identified the first example of a muscle protein in Japanese freshwater eels (Anguilla japonica) that fluoresces under special circumstances that may lead to improved medical testing (photo above).  The researchers have isolated the protein they named UnaG (after “unagi”, the term for freshwater eel in Japanese). What is unique about this protein is that it fluoresces under low oxygen conditions and when it binds to bilirubin, a byproduct of hemoglobin that is a common marker physicians measure for  liver health. Therefore, the discovery of this new protein may lead to better medical testing for bilirubin.

The muscle protein also fluoresces when exposed to blue light, which is how food chemists Seiichi Hayashi and Yoshifumi Toda from Kagoshima University in Japan discovered it in the popular sushi meat.

Sources:

Kumagai A, Ando R, Miyatake H, Greimel P, Kobayashi T, Hirabayashi Y, Shimogori T, Miyawaki A.  A Bilirubin-Inducible Fluorescent Protein from Eel Muscle. Cell. In Press.

Scientific American

KMSP-TV

Source

Herrera AM, Shuster SG, Perriton CL, Cohn MJ. Developmental basis of phallus reduction during bird evolution. Current Biology Published online June 6, 2013. doi: 10.1016/j.cub.2013.04.062

Blackbird image from: Ernie Janes/naturepl.com

A recent study has provided some evidence supporting the hypothesis that light and noise pollution alters the biological clocks of birds living in cities (compared to birds living in rural areas).  

Dr. Dominoni (Max Planck Institute for Ornithology, Germany) and colleagues used radio-pulse transmitters attached to European blackbirds (Turdus merula) living in Munich, Germany (city) and those living in a forest nearby to track the animal’s activity levels. They found that blackbirds living in the city showed significantly increased activity an average of 29 minutes earlier in the morning than blackbirds living in the forest.

When the birds were housed in a room with constant dim light, effectively eliminating time-of-day cues, the circadian rhythm of the city birds was 50 minutes shorter and the animal’s behavioural pattern became irregular more quickly compared to forest birds. The authors speculate that the irregular pattern may help the city birds adapt to their ever-changing, and often unpredictable, environment.

Sources:

Nature doi:10.1038/nature.2013.13137

Dominoni DM, Helm B, Lehmann M, Dowse HB, Partecke J. Clocks for the city: circadian differences between forest and city songbirds. Proceedings of the Royal Society B. 280(1763) [Epub ahead of print]

Caribbean sun anemone. Image from Wikimedia, Omar Spence Photography.

Dr. George Chandy at the University of California, Irvine discovered a toxin in Caribbean sun anemones (see photo) in 1984 and has spent his career studying the toxin. Prior work by his team suggested that a synthetic version of a peptide (ShK-186) from the toxin may help treat autoimmune disease.  It works by blocking a specific potassium channel (Kv1.3) important in immune system reactivity. Since potassium channels are also important in the regulation of metabolism and body weight, his team wanted to explore whether this peptide could be used to treat obesity. Mice on a diet high in fat and sugar were administered ShK-186, which decreased weight gain, fat deposits, cholesterol, blood sugar, and fatty liver. The hypothesis is that ShK-186 reduces inflammation and activates brown fat, known for its calorie-burning properties.

Source:

May 29 University of California, Irvine Press Release 

Tope 10 new species discovered in 2012. Image from: International Institute for Species Exploration, Arizona State University

My favorites:

The adorable tiny frog, Paedophryne amanuensis, from New Guinea that is only 7mm (pictured above on a dime). It is currently considered the smallest living vertebrate.

Glow-in-the-dark cockroaches, Lucihormetica luckae, from Ecuador (top right in composite above). Consider them night lights. Species of glow-in-the-dark roaches are mainly found in areas without light pollution.

To read more about these and the other 8 species, visit the website.  

Source:

International Institute for Species Exploration, Arizona State University

For example, did you know that male Dayak fruit bats can lactate to feed their young (True according to this article in Nature)? 

Image from “Crime Against Nature”, written and illustrated by Gwenn Seemel.

However, the notion that female spotted hyenas have a “penis” is not entirely accurate. It turns out that high-ranking alpha female hyenas are very aggressive and provide their developing offspring with higher levels of androgen (male sex hormone) than lower-ranking females in late pregnancy. This androgen boost increases the offspring’s chance of survival as it makes them more aggressive at fighting for food and at mating earlier and more often than those receiving less androgen.  The problem is that the high androgen levels damage the mother’s ovaries and cause her clitoris to enlarge (up to 7 inches), thereby resembling a penis. Since the opening of the vaginal canal is at the end of the clitoris, it makes birthing a 2-pound cub through a 2-inch canal dangerous and often fatal for first time mothers. (Source: Michigan State University press release).  

To judge the book for yourself, click here.

Image of atopic dermatitis from www.itchfreepet.com

Dr. Kerstin Lindblad-Toh at Uppsala University (Sweden) who specializes in comparative genomics and Dr. Åke Hedhammar, SLU (Sweden) recently identified a novel gene in German shepherd dogs, PKP-2, that encodes a protein (plakophilin-2) important for regulating proper skin structure and function. This protein was found to be associated with canine atopic dermatitis (i.e. doggy eczema), a condition that affects 3-10% of man’s best friends. Researchers hope that the discovery of this gene relationship may lead to better understanding of, and novel treatments for, eczema in both dogs and the 10-30% of humans who share this condition.

Source:

Uppsala University press release

A Cold War bunker at Loring Air Force Base in Maine that has been converted into a winter haven for bats. Image from: BBC News, USFWS/S. Agius

Scientists in Maine have converted two Cold War bunkers at Loring Air Force Base into winter havens for bats in an effort to protect the animals from the fungus that causes white nose syndrome. What is nice about using a man-made space is that they can actually clean up the area as opposed to trying to kill the fungus in a cave where multiple species of fungi may be affected, thereby disrupting the micro-ecosystem. The winter survival rate is not very high so far, only 9 out of 30 of the animals survived the stress of capture, transport, and captivity. The researchers have added roosts and closed captioning televisions to the bunkers to help study the animals. I hope their efforts at creating man-made safe havens for these bats works as this fungus has killed up to 6.7 million bats to date, and is continuing to spread.

For more information on these bunkers, visit BBC News.

For prior posts on white nose syndrome and bats:

North American Bats Face Possible Endangerment

White Nose Syndrome – Revisited

White Nose Syndrome and Evaporative Water Loss

Does Ketosis Occur During Hibernation?