Magnetotaxis
Magnetotaxis, something in common, genetically.
The theory of Magnetrition was inspired, and is based on the properties and behavior of magnetotactic bacteria, along with statistical data indicating, a high degree of movement required in/for the maintenance of warm-blooded metabolisms, or cellular deterioration corresponding with a lack of movement in warm-blooded metabolisms. Magnetrition predicts magnetotactic organelles serving the same function within warm-blooded cells, as does the phototactic chloroplast does in the plant cell. And, since the chloroplast are considered to be a corresponding organelle in plant cells, to the mitochondria in ours, I have been considering the latter organelle as the prime candidate predicted. However, after 20 some years of gathering data concerning the matter, along with indications that most lifeforms use the Earth's magnetic field as an aid in migration, so too are found indications that most organelles used magnetotaxis in their locomotion. And may do so due to genetic inheritance.
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It’s the network, stupid </view/generic/id/32048/title/It%E2%80%99s_the_network%2C_stupid>
The complexity of humans may lie not in genes but in the web of interactions among the proteins they make.
By Patrick Barry. May 12th, 2008.
Web of protein interactions reflects human complexity better than number of genes.
Humans don’t have many more genes than fruit flies or microscopic roundworms, but the network of protein interactions in human cells is much larger and more complex, a new estimate shows.
While people have only about 20,000 genes, the proteins encoded by those genes interact in roughly 650,000 ways. That network of interactions, or “interactome,” is about 10 times larger than that of the fruit fly and three times the size of the roundworm’s interactome.
While the interactome encompasses more of an organism’s complexity than the genome alone, Stumpf says that comparing interactomes captures only part of the total difference in complexity between species. Interactomes deal exclusively with proteins, but other kinds of molecules such as small RNAs are also cogs in a cell’s baroque machinery.
“It’s much, much more than just the organization of protein interactions,” Stumpf says. “There’s so much we don’t know. It’s such an exciting time.”
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Home </view/home> / News </view/latest> / December 15th, 2007; Vol.172 #24 </view/issue/id/9201/title/December_15th%2C_2007%3B_Vol.172_%2324> / News item
Cells' innards may share origin.
By Patrick Barry. December 11th, 2007.
From Washington, D.C., at a meeting of the American Society for Cell Biology
Despite their outward differences, many of the organelles within cells may have a common evolutionary heritage.
In a case of scientific serendipity, data gathered by separate research teams working on various organelles lend new support to the theory that a simpler cellular compartment gave rise to the organelles' diverse modern forms.
"We all had been looking at specific organelles, but sitting there [at the conference] listening to the other scientists speak, there seemed to be something common in all of them," says Damien Devos of the European Molecular Biology Laboratory in Heidelberg, Germany.
Several research groups had been studying proteins that guide the movements and interactions of organelles such as the Golgi apparatus, the endoplasmic reticulum (ER) and the nucleus.
"The data are contradictory if you look at one protein at a time," says Joel B. Dacks of the University of Cambridge in England. "But if you look at them together, it fits."
Each protein on an organelle has evolved at a different rate, so each tells a different story about how long ago that organelle might have diverged from an ancient, simpler organelle and begun developing unique functions.
But Dacks suggests that because all the proteins on one organelle must function together, a change in even one protein could be enough to send the whole compartment off in a new evolutionary direction.
Viewed this way, the measured similarities among the versions of organelle proteins such as Rab, SNARE, and Adaptin suggest they all evolved from a compartment in an ancestral cell that lived long before multicellular life arose, Devos and Dacks say. Such a scenario would contradict the idea that organelles such as the Golgi apparatus and the ER independently evolved, perhaps from pockets in the cell's outer membrane.
"They all came from the same place," Dacks postulates. However, even if further research supports the new theory, it would not apply to energy-converting mitochondria or sunlight-absorbing chloroplasts, which are known to have evolved from ancient, independent-living bacteria that became incorporated into the cells.
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Genetic mutations in cells' internal powerhouses could contribute to aging by stifling tissue maintenance.
Home </view/home> / News </view/latest> / July 30th, 2005; Vol.168 #5 </view/issue/id/6420/title/July_30th%2C_2005%3B_Vol.168_%235> / News item
Cell death may spur aging.
By Christen Brownlee. July 25th, 2005.
OL' MUTANT. Excess mutations in cells' power-generating organelles have aged the mouse on the right far faster than the normal mouse of the same age at left.J. Miller
Genetic mutations in cells' internal powerhouses could contribute to aging by stifling tissue maintenance, according to new research.
These power-generating organelles, known as mitochondria, have their own DNA separate from that in a cell's nucleus. In a previous study, researchers in Sweden created mutant strains of mice that accumulated excess mitochondrial mutations. The mice aged faster than normal, suggesting that mutations contribute to aging.
Tomas Prolla of the University of Wisconsin-Madison and his colleagues set out to find out just how the mutations might be doing this. Working with the same mutant-mouse strain that the Swedish researchers did, Prolla's team measured levels of cell death, or apoptosis, in several different tissues. When compared with tissues from normal mice, many of the tissues in the mutant strain showed significantly more apoptosis. The researchers suggest that the damaged mitochondria prompt cells to die.
Prolla and his colleagues note in the July 15 Science that the loss of critical cells, such as stem cells responsible for maintaining most tissues, could lead to gray hair, failing senses, and other signs of old age.
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Home </view/home> / News </view/latest> / March 5th, 2005; Vol.167 #10 </view/issue/id/5941/title/March_5th%2C_2005%3B_Vol.167_%2310> / News item
Cytoplasm affects embryonic development.
By Christen Brownlee. February 28th, 2005.
New research provides the best evidence yet that a fertilized egg's nucleus isn't the sole site of control for an embryo's development. Signals emanating from the cell's mitochondria-its power-generating organelles-also appear to influence how an organism grows.
Mitochondria carry their own DNA, which is unrelated to the genetic material in a cell's nucleus. Scientists have been unsure whether mitochondrial DNA has an impact on developmental processes.
To investigate this, Zuo-Yan Zhu and his colleagues at the Chinese Academy of Sciences in Wuhan cloned carp through a technique called nuclear transfer. This method removes the nucleus from one cell and inserts it into an egg that has had its own nucleus removed. However, instead of inserting carp nuclei into carp eggs, Zhu's team inserted them into goldfish eggs.
Normal carp have 33 to 36 vertebrae. However, the resulting cloned fish had between 26 and 28 vertebrae-the same number as goldfish-suggesting that mitochondrial DNA in the goldfish eggs had affected the carps' development.
Zhu notes that these results, published in the March Biology of Reproduction, may make researchers think twice about proposals to clone extinct animals using the eggs of living species.
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http://www.origin-of-mitochondria.net/?attachment_id=136
Posetd by Albert de Roos on Sunday, May 27, 2007, at 00:58, and filed under morphology <http://www.origin-of-mitochondria.net/?cat=1>.
Stage I (35-300 um): During early stage I (35-75 um diameter), the distinctive polarity of stage 0 oocytes is lost, and oocytes appear symmetrical in shape and cytoplasmic organization. The growing nucleus, or germinal vesicle (GV), moves to the center of the oocyte and cytoplasmic organelles, such as mitochondria, become dispersed throughout the cytoplasm (JPEG: 55 KB). Mitochondria begin to aggregate into perinuclear clumps, and by mid-stage I, oocytes contain one or two prominent mitochondrial aggregates, variously referred to as the Balbiani bodies, mitochondrial clouds, or mitochondrial masses (JPEG: 52 KB). These masses are readily visible in light micrographs of the transparent, pre-vitellogenic, stage I oocytes (JPEG: 9 KB). The granular fibrillar germ plasm is associated with the mitochondrial mass of stage I oocytes, as are several maternal RNAs. From here <http://www.biology.utah.edu/gard/HTML/Oogenesis/Oogenesis_body.htm>.
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old hypotheses
The mitochondrion as a reduced nucleus <http://www.origin-of-mitochondria.net/?p=181>
2007 08 19 Albert de Roos.
When I started this work, I still thought of the mitochondrion as an independent unit, and pondered the possibility that the proto-mitochondrion was a reduced nucleus due to a mitosis gone wrong. In this way, two interdependent cells were obtained. The first would be the nucleus but without essential metabolic proteins, the second a remnant […]
http://www.origin-of-mitochondria.net/
http://www.origin-of-mitochondria.net/?page_id=226