cell biology
gregladen | November 13, 2008Imagine that you are a bad guy running from the law, and the sheriff is about to catch up to you. If you want, you can be Butch Cassidy or the Sundance Kid or any other charismatic bad guy. Or maybe you're a wizard in Harry Potter and Dementors are about to catch up to you.
But then, just as the sheriff, or the Dementor, or whatever, catches up, you wave a magic wand and instead of killing or capturing you, your nemesis transforms into a big tent inside of which you can hide. And the tent is made out of food that you can eat.
This, metaphorically (and thus not exactly accurate, but…
gregladen | October 13, 2008 A very good day of grunting worms. Credit: Ken Catania So-called Gene-Culture Co-Evolution can be very obvious and direct or it can be very subtle and complex. In almost all cases, the details defy the usual presumptions people make about the utility of culture, the nature of human-managed knowledge, race, and technology. I would like to examine two cases of gene-culture interaction: One of the earliest post-Darwinian Synthesis examples addressing malaria and sickle-cell disease, and the most recently published example, the worm-grunters of Florida, which it turns out is best explained…
gregladen | September 29, 2008An article just out in PLOS Biology explores one of the most important, but also difficult to observe, phenomena related to DNA regulation.
Figure 1 from the paper: "Atomic Force Microscopy of Lac Repressor-DNA Complexes (A) Schematic structures of biotin (bio)- and digoxigenin (dig)-labeled DNA constructs with one (O-539 and O-349) or two (O-153-O and O-158-O) ideal lac operator sequences (white bars)... (B) AFM image of molecules adsorbed to a mica surface ... (C) Scatter plot of the DNA arm contour lengths in repressor-DNA complexes....(D and E) Left: projection images of two…
gregladen | June 20, 2008Blood flow in the brain is linked to neuronal activity. Therefore, various 'brain scanning' techniques can be used to observe neuronal activity in the brain. This has led to an astonishing revolution in knowledge of how the brain works. Of course, you knew that already.
Also astonishing is that the reason for changes in blood flow in relation to what neurons are doing is unknown! We know this system works, but we don't know why!
Until now...
It turns out that it is the glia cells. There a different kinds of glia, and they are very important in brain function. Glia do a lot of…
gregladen | April 25, 2008Life is complex. The way a living system works can be described in a series of increasingly refined models, each fleshing out details of the previous model. Typically, description at one level raises questions about what is happening at the finer level. These questions induce hypotheses which drive experimental work which produces ever more detailed knowledge.
A paper about memory, just published, is an example of one incremental step in this process. In short, this research works out some of the fine detail at the molecular level for the process of forming visual memories.
In mammals…
gregladen | April 18, 2008Good question ... what IS in the air?
The simple answer is that the air ... the Earth's atmosphere ... is about 78% nitrogen, 21% oxygen, with a tiny amount of some other gases including water vapor. Then, there's dirt. I want to talk a little about the oxygen, one of the other gases (carbon dioxide to be exact), the water vapor, and the dirt.
Oxygen
The oxygen is one of the most important parts to us because we (and all the other animals) need it to breath. To me, what is most interesting about the oxygen is that in the old days ... before any animals or plants evolved but life…
gregladen | April 5, 2008There is an updated version of this post here: "Is Blood Ever Blue, Science Teachers Want To Know!"
According to one of the leading experts on the human circulatory system, blood flowing through veins is blue.
I'm not going to mention any names. All I'll say is this: A person I know visited a major research center last year and saw a demonstration of organ removal and some other experimental stuff. A person also visiting asked the famous high-level researcher doing this work if blood was ever blue. What he said was not recorded in detail, but it was very much like this statement I found…
gregladen | March 11, 2008Photosynthesis; This is how the British to it (teaching, not photosynthesis). From Crackle: Biology Education - Photosynthesis for GCSE / K12 ...
I'm not sure why he says we don't know how photosynthesis works.
Look at how well behaved the students are. You can tell this is not America, even without noticing that the guy talks funny.
The graph on the rate of photosynthesis is idealized. This is not the graph for all plants. This won't work for your Alaskan Peas, for instance.
Notice the maximum value for effect on increased CO2. I wonder what ever happened to the old chap..
gregladen | February 29, 2008are here:
HIV infection at Wissen schafft Kommunikatioin
Other cellular stuff (an oldie but a goodie) at WeiterGen!
purepedantry | February 14, 2008You have got to see this video.
Sakaue-Sawano et al. may have created the coolest molecular biology video I have ever seen. They developed a system of reporters to watch the cells transition between the different stages of the cell cycle.
This is cool, but it is going to take a bit of explaining to understand why.
Background
All cells go through a cycle of steps in order to replicate their DNA and divide into two new cells. This cycle is called the cell cycle, and it is characterized by the presence of certain tightly coordinated proteins during each particular stage. I am referring to…
gregladen | February 12, 2008"Disease" is a big word. I'd like to address this question by focusing on the difference, or lack of difference, between a poison, a disease, and a yummy thing to eat. It turns out that they may all be the same. Yet different.
Phenylketonuria (fee-null-keet-o-noo-ria), mercifully also known as "PKU" (pee - kay - you) is a disorder in which the amino acid phenylalanine is not broken down by an enzyme (phenylalanine hydroxylase) and thus accumulates in the body as phenylpyruvic acid.
This is bad because phenylpyruvic acid interferes with normal development of neural tissues.
In western…
gregladen | February 10, 2008Men are largely useless, and worse, detrimental to normal operation of a society. But they have been retained because they were the only known source of sperm. Not any more.
British scientists are ready to turn female bone marrow into sperm, cutting men out of the process of creating life.
The breakthrough paves the way for lesbian couples to have children that are biologically their own.
Gay men could follow suit by using the technique to make eggs from male bone marrow.
Researchers at Newcastle upon Tyne University say their technique will help lead to new treatments for infertility.
But…
gregladen | February 6, 2008
The scientists have created the embryo in the lab
Scientists believe they have made a potential breakthrough in the treatment of serious disease by creating a human embryo with three separate parents.
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