Medescape

Skepticism, Medicine and Science News

Filming The Immune System

Scientists at Sydney’s Centenary Institute recently managed to film an immune cell in the process of being invaded by the parasite Leishmania. The study was published in PLoS Pathogens

This is the first time this process has been filmed, and it was made possible by using high powered multi-photon microscopy which allowed the cells to be viewed in real time. Using this technique, head researcher Wolfgang Weninger and his team were able to study dendritic cells in the skin after the introduction of Leishmania parasites. This ability to track pathogens in the immune system is likely to benefit vaccine research and other studies of the immune system in general. 

This image shows an immune cell absorbing the parasite via pseudopods. The parasite is shown in red, and the blue circles are vacuoles containing parasites.   

The full study can be found here, and there are some really cool videos included in “Supporting Information” part the article. I recommend taking a look at them.

December 7, 2008 Posted by | Biology, Medicine | , , , , , , , , , , , , , , , , , | Leave a comment

Sneaky Cats

Evolutionary researchers at Duke University recently published a study where they investigate the differences in gait between cats and dogs, seen from an evolutionary point of view. What they found was that evolution seems to have take two entirely different paths. Dogs have a very energy-efficient style of running, so they can chase prey over larger areas without burning too much energy. Cats on the other hand have a much more inefficient gait, but it is perfect for slow movements, enabling them to sneak up on prey covertly. The study was published in the Public Library of Science.

In the study, Kristin Bishop, Daniel Schmitt and Anita Pai videotaped six housecats moving along a runway chasing food/toys++. They found that the cats were able to reduce the muscular work needed to move forwards by about 37%, while long-distance predators, like dogs, are able to reduce it by 70%. This suggest a trade-off for the cats where the ability to move stealthily evolved at the cost of more inefficient gait. 

Oh, and humans have about the same gait efficiency as dogs, ie about 70%. Hurray for bipedalism! 

December 4, 2008 Posted by | Biology, Evolution, Creationism and ID | , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

New Dolphin Species

Due to unforeseen, unwanted and, I presume, unintended events, the network at my flat died over night. This post will therefore be quite short, since I’m doing it from a public computer.

I’ll just inform everybody that a new species of dolphin have been discovered near southern Australia. It was discovered using DNA analysis, and has been given the name Southern Australian bottlenose.

The Southern Australian bottlenose dolphin. Credit: Macquarie University

November 21, 2008 Posted by | Biology, General Science | , , , , , , , , , | Leave a comment

New, cool bacterium

A new bacterium was just discovered in the Mponeng goldmine in South Africa. It has been named Candidatus Desulforudis audaxviator , and the really interesting thing about it is that it lives in a community of only one species, which is extremely unusual. Another interesting bit is how it gets its energy. 

Oxygen is toxic to it, so instead it uses the radioactive decay of uranium in the surrounding rocks to provide it with energy. It gets carbon from dissolved carbon dioxide, and nitrogen from the surrounding rocks. It has got a lot of attention from astrobiologists because it represent a kind of bacteria that can be able to live beneath the ground on Mars, and on Enceladus, one of Saturns moons.

October 10, 2008 Posted by | Biology | , , , , , , | 1 Comment