cell biology
gregladen | January 18, 2008"MIT researchers have discovered why an unusually short bacterial protein can have many more interactions than would normally be expected of something its size."
The team, led by biology professor Graham Walker, found that the protein, UmuD, belongs to a recently discovered class of proteins called intrinsically disordered proteins.
Proteins, which consist of chains of amino acids, locally fold themselves into one of two structures--a helix or a pleated sheet. In contrast, intrinsically disordered proteins lack such well-defined local structures.
The lack of formal structure probably allows…
gregladen | January 18, 2008There is a discussion on the internet about Junk DNA, that includes a discussion at Sandwalk (Larry Moran's blog) ... I made a comment there about genome size that was responded to by T.R. Gregory. I started to write my response in Larry's Little Box, but realized that it would not fit. So it is here:
Imagine a gene family distributed among all the species in a given taxon. There are several alleles per gene. The gene codes for an enzyme that plays a role in determining cell size. Different combinations of genes/alleles exist to cause cell size to vary such that each species has a…
gregladen | January 13, 2008Cells do things (or stop doing things) because of internal homeostatic (or other) regulatory mechanisms, or because of communication with the "outside" via receptor sites located on the cell membrane. To get cells to do what we want (produce more or less of a hormone, for instance, or simply to die as in the case of cancer cells) it would be nice to have a machine that you point at a patient, program a few dials and buttons, and then affect the receptor sites in that person's cells.
Well, the production model isn't quite ready yet, but such a device now exists on both the drawing board and…
gregladen | January 9, 2008A glow in the dark pig has given birth to more glow in the dark pigs.
Fluorescent Chinese pig passes on trait to offspring from PhysOrg.com
A pig genetically modified in China to make it glow has given birth to fluorescent piglets, proving such changes can be inherited, state media said Wednesday.
[...]
The pigs were originally modified (to glow) using somatic cell nuclear transfer.It is not entirely clear to me how the gene got into the gametes. It also appears that the distribution of the gene in the offspring is not exactly the same as in the parent, suggesting something interesting…
gregladen | January 7, 2008A group of scientists ... has uncovered a new biological mechanism that could provide a clearer window into a cell's inner workings.....What's more, this mechanism could represent an "epigenetic" pathway -- a route that bypasses an organism's normal DNA genetic program -- for so-called Lamarckian evolution, enabling an organism to pass on to its offspring characteristics acquired during its lifetime to improve their chances for survival.
Giardia surfaces are known to adapt to a host's immune response, and pass this on to daughter cells during cell division. That would be a system of…
gregladen | January 6, 2008From a Massachusetts Institute of Technology press release:
researchers have uncovered a critical difference between flu viruses that infect birds and humans, a discovery that could help scientists monitor the evolution of avian flu strains and aid in the development of vaccines against a deadly flu pandemic.
A quick word about viruses and receptor sites. I have always found the terminology to be a bit counter-intuitive and possibly misleading. The word "receptor site" almost sounds like a feature that a cell has in order to receive, allow in, provide a reception for a virus, as though…
gregladen | January 3, 2008This teaching simulation of the Sodium Potassium pump just showed up in my inbox. Have a look.
gregladen | December 3, 2007Why am I doing this...
You may have wondered why I am always putting cell biology videos up on my site. I'm doing it for a few reasons. One is to provide a resource for teachers. Some day in the not too distant future one will be able to enter "cell biology" in the search box (upper left from your perspective) and get a few peer reviewed research papers and a bunch of movies.
Pursuant to this is the possibility that others will watch the films and comment (Thanks Larry, especially, for doing a lot of that). Not all films are good, not all films are usable. You could go on Youtube and…