DINAIN, kinesin and Dynamin
The operation of actin-myosin complex becomes clear that cytoskeletal structures are ideal as support points, guides and transmission lines of the forces developed by molecular motors in cells. Not surprisingly, therefore, that the microtubules more rigid and stronger than actin filaments, constitute support for the operation of other molecular motors. And in retrospect, does not cause much astonishment that such engines are designed under the same principle as myosin. In fact, at least in the first case we will discuss below, are very similar (Table 1).
The DINAIN - protein force - is another mecanoenzima that uses energy from ATP hydrolysis to temporarily change its shape. It is also a large molecule composed of several subunits, the largest of which are two globular heads with a weight of 410 000 daltons each, in which resides the ATPase activity. This activity increased substantially in the presence of microtubules. The DINAIN was initially identified as the engine driving the movement of vibrating appendages called cilia and flagella that certain cells have. More recently it became obvious that there are other ways DINAIN distributed in the cytoplasm of a wide variety organisms.
The hallmark of DINAIN is its ability to move on microtubules in the same way as does myosin on actin filaments (Figure V.4). It is worth mentioning that this interaction is on the outside and not by the light of microtubules close as anyone could reasonably think. It appears that DINAIN heads are secured to a site on the wall of microtubules, then suddenly change shape, and then off to straighten and lock in a new site, constantly repeating the cycle while ATP available.
The ATP-ase in the Exonemo breaks the molecules of ATP and thus obtains energy for the movement of sperm. There is a theory by which the sperm move through a mechanism oscillator. Alternating sweeps right and left, the microtubules of the tail.
Spermatozoa.
sperm metabolism is aerobic and Cl and Mg ions promote motility. While the Ca +2 ion inhibits motility.
For proper motility is necessary to open Ca +2 channels and there is a change in the concentration of nucleotides in the Exonemo in the proximal portion of the tail.
In addition, any substance that inhibits the enzyme activity in sperm is a toxic substance for which hinders their motility.
The movement begins in the proximal portion of the tail (axoneme) and goes into the final. The sheath protein controls the tail beating, so it is not very sharp. There are a number of glands that release fundmental seminal fluid for sperm travel. The glands are in the path of it. So will acquire motility along the epididymis, the vas deferens, with the secretions of various glands.
In the bull, sperm speed is 72 microns per second and man, 35 to 50. The optimum pH is 7.5.
The fetal testis is an endocrine organ, acting as such. Is very different from ovarian feta, because the testicle produces a large amount of hormones. Among them:
• Testosterone: synthesized by fetal Leydig cells.
• AMH (AMH), synthesized by Sertoli cells.
sperm structure
The sperm will have a head, which houses the core and a structure that allows motility (tail). In the anterior nucleus is the acrosome, which is under the plasma membrane and leads enzymes released at fertilization. Behind the head, the neck is the region containing the centriole.
Cola: In the thickest part is the axoneme, where mitochondria. After the tail is tapered. Along the line, there are common structures, microtubules. There are 9 pairs of peripheral microtubules and a central pair. They are composed of protofilaments. One of the rings are 13 and 11 protofilaments.
The protofilaments consist of:
• Tubulin : two dimers (a1, a2 [also a, b])
• Histone .
• dynein : Is an ATPase. The role is to act on the mitochondria and ATP provide the sperm movement.
dynein arms are very important. Kartagener syndrome in man (also been studied in rats) individuals are unable to synthesize dynein. Its non-motile sperm, as well the hair cells of the respiratory tract and have great rates of respiratory diseases. Their hearts are on the right side "situs inversus."
The hallmark of DINAIN is its ability to move on microtubules in the same way as does myosin on actin filaments (Figure V.4). It is worth mentioning that this interaction is on the outside and not by the light of microtubules close as anyone could reasonably think. It appears that DINAIN heads are secured to a site on the wall of microtubules, then suddenly change shape, and then off to straighten and lock in a new site, constantly repeating the cycle while ATP available.
The ATP-ase in the Exonemo breaks the molecules of ATP and thus obtains energy for the movement of sperm. There is a theory by which the sperm move through a mechanism oscillator. Alternating sweeps right and left, the microtubules of the tail.
Spermatozoa. 
sperm metabolism is aerobic and Cl and Mg ions promote motility. While the Ca +2 ion inhibits motility.
For proper motility is necessary to open Ca +2 channels and there is a change in the concentration of nucleotides in the Exonemo in the proximal portion of the tail.
In addition, any substance that inhibits the enzyme activity in sperm is a toxic substance for which hinders their motility.
The movement begins in the proximal portion of the tail (axoneme) and goes into the final. The sheath protein controls the tail beating, so it is not very sharp. There are a number of glands that release fundmental seminal fluid for sperm travel. The glands are in the path of it. So will acquire motility along the epididymis, the vas deferens, with the secretions of various glands.
In the bull, sperm speed is 72 microns per second and man, 35 to 50. The optimum pH is 7.5.
The fetal testis is an endocrine organ, acting as such. Is very different from ovarian feta, because the testicle produces a large amount of hormones. Among them:
• Testosterone: synthesized by fetal Leydig cells.
• AMH (AMH), synthesized by Sertoli cells.
sperm structure
The sperm will have a head, which houses the core and a structure that allows motility (tail). In the anterior nucleus is the acrosome, which is under the plasma membrane and leads enzymes released at fertilization. Behind the head, the neck is the region containing the centriole.
Cola: In the thickest part is the axoneme, where mitochondria. After the tail is tapered. Along the line, there are common structures, microtubules. There are 9 pairs of peripheral microtubules and a central pair. They are composed of protofilaments. One of the rings are 13 and 11 protofilaments.
The protofilaments consist of:
• Tubulin : two dimers (a1, a2 [also a, b])
• Histone .
• dynein : Is an ATPase. The role is to act on the mitochondria and ATP provide the sperm movement.
dynein arms are very important. Kartagener syndrome in man (also been studied in rats) individuals are unable to synthesize dynein. Its non-motile sperm, as well the hair cells of the respiratory tract and have great rates of respiratory diseases. Their hearts are on the right side "situs inversus."
References. E. Frixione
Meza I. (2006) Living Machines How Cells are moved? Fondo de Cultura Economica . Mexico, DF ISBN 6-4988-5 968-l
Electronic References.
Reproduction.
floating fertilization.
http://ciencia.nasa.gov/headlines/images/fertility/graveffects_med_sp.gif
New scientific.
http://www.novaciencia.com/2006/11/28/pildora-para-bloquear-la-eyaculacion/
Medline Plus
http://www.nlm.nih. gov/medlineplus/spanish/ency/esp_imagepages/9875.htm
Recuperados on 10 April 2007.
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