Posted by: Dan | August 19, 2007

Cells Weekly #42

The image above is from the work of Del Alamo et al., in the August 14th PNAS, on the Spatio-temporal analysis of eukaryotic cell motility by improved force cytometry.

In the interests of promoting science posts relating (however broadly) to my interests of cell and molecular biology, here’s my biweekly installment of “Cells Weekly,” a showcase of topical blog posts by others from the past week.

MIT Creates 3D Images of Living Cell – New ways to image cells are always extremely useful tools, and this one is no different. Check it out over at Biosingularity.

What Are DprA and ComM’s Real Jobs? – Rosie chats about a pair of gene products whose functions aren’t known, but speculated to be involved with DNA uptake and repair. At RRResearch.

Cancer Immune Escape – Ian gives us a run down of some of the major aspects of cytotoxic T lymphocytes and evasion of them by cancer cells, in contrast to his past expositions on viral immune escape. At Mystery Rays from Outer Space.

Microbial Endocrinology: A Coming of Age – Moselio explores the relationships between bacteria and hormones, especially in the intestinal tract. At Small Things Considered.

RecA – And more telic nonsense from MikeGene. Question: How does he tell the existence of homologous recombination is purposeful? Answer: He says it just is (take notes kids, this is how not to interpret science). At The Design Matrix.

Late additions:

Relieving Tensin Relaxes Cells, Helps Migration – My own recent post, which I suppose I should’ve mentioned, focuses on a new report on tensin homologs and focal adhesion turnover.

From Adhesion to Migration: The Tensin Switch – Kim describes the same paper as I did, providing added perspective. At the Cell Migration Gateway.

p53 and RhoA Signalling: A Round About Way for Tumour Invasion – Kim explains how knocking out the tumour suppressor p53 causes cells to shift from an elongated to a rounded morphology, which is associated with increased motility and tumour invasiveness. Also at the Cell Migration Gateway.

Carnivals: I and the Bird #55, Encephalon #29, Tangled Bank #86, Oekologie #8.

And some science picks below the fold:

Scientists Discover The Dynamics Of Transcription In Living Mammalian Cells

Transcription — the transfer of DNA’s genetic information through the synthesis of complementary molecules of messenger RNA — forms the basis of all cellular activities. Yet little is known about the dynamics of the process — how efficient it is or how long it takes. Now, researchers have measured the stages of transcription in real time. Their unexpected findings have fundamentally changed the way transcription is understood.

Discovery Of New Protein Could Provide New Understanding Of Male Fertility

Scientists have discovered a new enzyme involved in the degradation of proteins inside cells, a process that helps eliminate or recycle proteins that are no longer needed. The unexpected discovery overthrows the idea that protein degradation is initiated by only one enzyme. Also, the new enzyme is very highly expressed in the testis, which could provide a new understanding of male fertility.

Immunity In Social Amoeba Suggests Ancient Beginnings

Finding an immune system in the social amoeba (Dictyostelium discoideum) is not only surprising but it also may prove a clue as to what is necessary for an organism to become multicellular, according to a new article.

Scientists Discover A Control Mechanism For Metastasis

A team of biologists, physicists and doctors has revealed a cellular mechanism that controls the movement of cells in cancer metastasis. This finding may help predict the progression of metastasis, as well as the design of drugs to prevent it.

How Cells Change The Pace Of Their Steps

For the first time, scientists have been able to make precise measurements of the repetitive forces and strain energies exerted by cells on the move, information with broad significance to medical research.

Functioning Neurons From Human Embryonic Stem Cells Produced

Scientists were able to produce from human embryonic stem cells a highly pure, large quantity of functioning neurons that will allow them to create models of and study diseases such as Alzheimer’s, Parkinson’s, prefrontal dementia and schizophrenia.

From Microscopy To Nanoscopy

Scientists have developed optical 3-D far-field microscopy — with nanoscale resolution, good signal-to-noise ratio and short exposure times using special photo-switchable fluorescence dyes.

Cell Death By Necrosis Leads To Heart Failure

The prevalence of heart failure continues to increase in the Western world, making it one of the biggest killers in this region. It is characterized by loss of the muscle cells of the heart (cardiomyocytes). Although this loss is generally considered to occur mostly through a process known as apoptotic cell death, a new study indicates that cell death by necrosis also has a role in the cardiomyocyte loss that accompanies heart failure in mice.

New, More Direct Pathways From Outside The Cell-to-cell Nuclei Discovered

Researchers have shattered a long-held belief that no direct pathway exists between material outside of a cell and the cell nucleus. The cell is the smallest metabolically functional unit of life.


  1. Hi Dan,

    Thank you for your continued interest in the RecA function. I don’t agree with your characterization of what MikeGene said and didn’t say, but since I am asking for a favor, I won’t dwell on that. I was hoping you could respond to a possible experiment for RecA…

    Supposed we use the “lab strain of E. coli is known as DH5alpha” which has the RecA function removed as a test group. This test group and a control group (E. coli with RecA function intact) could be exposed to very low level UV radiation and some kind of environmental pressure.

    It would be expected that the DH5alpha would mutate more often because of the lack of the RecA repair function. Therefore, based on RM+NS, the test group should evolve faster in response to the environmental pressure (at a predictable rate). If the evolutionary rate is significantly lower than predicted then wouldn’t that suggest the recA gene is directly involved in supporting beneficial mutations (i.e. an evolution gene)?

    Please don’t worry about being polite. If it is a stupid suggestion, say so. However, I would be interested in understanding why it is a stupid suggestion.


  2. Hi TP,
    A clarification please on your proposed experiment: How would you intend to measure evolution rates, in this instance?

    Also, yes, I am rather inclined to be suspicious of the term ‘evolution gene’ in general. There’s no doubt that DNA repair and recombination facilitate variation, and that this is a vital step in the outcome that we call evolution – but that’s not the same thing as facilitating natural selection. As it is, the experiment you suggest appears to be a test for mutation rates rather than evolution rates, does it not?

  3. Incidentally, Ed Darrell has linked to a separate article, explaining the difference between a crackpot genius and an actual genius:

    In his book Cranks, Quarks and the Cosmos, science writer and physicist Jeremy Bernstein points out that one of the criteria that always defines crank ’science’ is its lack of correspondence with the body of scientific knowledge that has gone before it.

    “I would insist that any proposal for a radically new theory in physics, or in any other science, contain a clear explanation of why the precedent science worked,” he writes. Einstein did this, as the first page of his paper on special relativity, “On the Electrodynamics of Moving Bodies”, illustrates perfectly.

    In contrast, “the crank,” Bernstein writes, “is a scientific solipsist who lives in his own little world. He has no understanding nor appreciation of the scientific matrix in which his work is embedded … In my dealings with cranks, I have discovered that this kind of discussion is of no interest to them.”

    Now, I’m NOT claiming that MikeGene has little understanding or appreciation of the current ediface of science, and he is trying to fit his views into the precedent science. So in this sense, crank may not be the correct term.

    However, MikeGene is also still solidly in the realm of pseudoscience, and while he doesn’t contest the precedent science, he DOES infer agency, intelligence and purposefulness in the theological sense. And while he, in comments, admits that he is not proposing an actual scientific view, he frames his posts as though they espouse objective/scientific views. This is dishonest, hence my invocation of the term crank.


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