Oooh look. Human cells operate like microbes...
Offline Human Cells Exhibit Foraging Behavior Like Amoebae and Bacteria
ScienceDaily (Mar. 13, 2010) — When cells move about in the body, they follow a complex pattern similar to that which amoebae and bacteria use when searching for food, a team of Vanderbilt researchers has found.
The discovery has a practical value for drug development: Incorporating this basic behavior into computer simulations of biological processes that involve cell migration, such as embryo development, bone remodeling, wound healing, infection and tumor growth, should improve the accuracy with which these models can predict the effectiveness of untested therapies for related disorders, the researchers say.
"As far as we can tell, this is the first time this type of behavior has been reported in cells that are part of a larger organism," says Peter T. Cummings, John R. Hall Professor of Chemical Engineering, who directed the study that is described in the March 10 issue of the Public Library of Science journal PLoS ONE.
The discovery was the unanticipated result of a study the Cummings group conducted to test the hypothesis that the freedom with which different cancer cells move -- a concept called motility -- could be correlated with their aggressiveness: That is, the faster a given type of cancer cell can move through the body the more aggressive it is.
"Our results refute that hypothesis -- the correlation between motility and aggressiveness that we found among three different types of cancer cells was very weak," Cummings says. "In the process, however, we began noticing that the cell movements were unexpectedly complicated."
Then the researchers' interest was piqued by a paper that appeared in the February 2008 issue of the journal Nature titled, "Scaling laws of marine predator search behaviour." The paper contained an analysis of the movements of a variety of radio-tagged marine predators, including sharks, sea turtles and penguins. The authors found that the predators used a foraging strategy very close to a specialized random walk pattern, called a Lévy walk, an optimal method for searching complex landscapes. At the end of the paper's abstract they wrote, "…Lévy-like behaviour seems to be widespread among diverse organisms, from microbes to humans, as a 'rule' that evolved in response to patchy resource distributions."
This gave Cummings and his colleagues a new perspective on the cell movements that they were observing in the microscope. They adopted the basic assumption that when mammalian cells migrate they face problems, such as efficiently finding randomly distributed targets like nutrients and growth factors, that are analogous to those faced by single-celled organisms foraging for food.
With this perspective in mind, Alka Potdar, now a post-doctoral fellow at Case Western Reserve University and the Cleveland Clinic, cultured cells from three human mammary epithelial cell lines on two-dimensional plastic plates and tracked the cell motions for two-hour periods in a "random migration" environment free of any directional chemical signals. Epithelial cells are found throughout the body lining organs and covering external surfaces. They move relatively slowly, at about a micron per minute which corresponds to two thousandths of an inch per hour.
When Potdar carefully analyzed these cell movements, she found that they all followed the same pattern. However, it was not the Lévy walk that they expected, but a closely related search pattern called a bimodal correlated random walk (BCRW). This is a two-phase movement: a run phase in which the cell travels primarily in one direction and a re-orientation phase in which it stays in place and reorganizes itself internally to move in a new direction.
In subsequent studies, currently in press, the researchers have found that several other cell types (social amoeba, neutrophils, fibrosarcoma) also follow the same pattern in random migration conditions. They have also found that the cells continue to follow this same basic pattern when a directional chemical signal is added, but the length of their runs are varied and the range of directions they follow are narrowed giving them a net movement in the direction indicated by the signal.
"For the first time, this gives us a general framework for analyzing the way cells move," says Potdar.
http://www.sciencedaily.com/releases/2010/03/100311123622.htm
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
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Taken from some random site:
"Electrons orbiting around inside their particular ‘cloud’ – are many in some cases and few in others. It’s a bit mind boggling and , if only we could see it, we might think it resembled a section of a small universe."
Consider that statement and incorporate a bit of imagination, for example the box in a box in a box etc etc, scary huh.
Yea I'm weird and this has been on my mind off and on through the years.
Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin
If you keep speculating like this, Pais is going to accuse you of embracing the woo...
Having said that, I know what you mean. There's something weird going on out there.
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
Yea, this stuff is amazing. I read an article the other day about how colonies of single cell slime molds could be taught to change their metabolism in response to timed events. Like, how the fuck does that happen, they are single cell organisms!?
http://discovermagazine.com/2009/jan/071
Everything makes more sense now that I've stopped believing.
Something about your post just reminded me of it.
I'm sure it's a theory written down somewhere I have not found it though.
Seems like I read some sci-fi short story where a scientist made a super microscope and discovered that deep in cells it was like a small universe where life such as our own existed. He went crazy and was put in a mental institution saying something like "we could be a miniscule part of a cancer in someones scrotum." or some such.
In reality this theory would be at least as likely as a "god" imo.
Sorry if I'm derailing your original post.
Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin
I was all excited to challenge the study- then I got to one of the last lines and they tied up the huge loose end that is chemical mediators.
Really amazing stuff. It's already known how complex a single cell is, but to know that any cell from any body follows a similar movement pattern when migrating is mind blowing. If this ends up panning out, we may be looking at a way to finally understand how pathologies develop,progress, and act on the body-- and perhaps find ways to pharmacologically alter those processes and start curing some chronic diseases.
As long as it isn't God... I'm cool with it.
edit: fucking random omission of words... GNNNNAARRRFF!
“A meritocratic society is one in which inequalities of wealth and social position solely reflect the unequal distribution of merit or skills amongst human beings, or are based upon factors beyond human control, for example luck or chance. Such a society is socially just because individuals are judged not by their gender, the colour of their skin or their religion, but according to their talents and willingness to work, or on what Martin Luther King called 'the content of their character'. By extension, social equality is unjust because it treats unequal individuals equally.” "Political Ideologies" by Andrew Heywood (2003)
It sounds like hoodoo to me; electron clouds are very different thing going on.
The patterned movement of the cells is interesting, though.
Ok so, a red box, in a blue box in a green box etc..
Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin