نتایج جستجو برای: near pole polar diagram
تعداد نتایج: 381492 فیلتر نتایج به سال:
Polar cells have been described as pairs of specific follicular cells present at each pole of Drosophila egg chambers. They are required at different stages of oogenesis for egg chamber formation and establishment of both the anteroposterior and planar polarities of the follicular epithelium. We show that definition of polar cell pairs is a progressive process since early stage egg chambers con...
The generation and maintenance of subcellular organization in bacteria is critical for many cell processes and properties, including growth, structural integrity and, in pathogens, virulence. Here, we investigate the mechanisms by which the virulence protein IcsA (VirG) is distributed on the bacterial surface to promote efficient transmission of the bacterium Shigella flexneri from one host cel...
Type IV secretion is used by pathogenic microorganisms to transfer effector macromolecules to eukaryotic target cells. The VirB/D4 apparatus of Agrobacterium tumefaciens transfers DNA and proteins to plant cells. We postulated that the cell pole is the site of assembly of the A. tumefaciens type IV apparatus. Using immunofluorescence microscopy, we now demonstrate that 10 of the VirB proteins l...
[1] The first Martian year and a half of observations by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter has revealed new details of the thermal structure and distributions of dust and water ice in the atmosphere. The Martian atmosphere is shown in the observations by the Mars Climate Sounder to vary seasonally between two modes: a symmetrical equinoctial structure with middle a...
BACKGROUND Germline formation is a highly regulated process in all organisms. In Drosophila embryos germ cells are specified by the pole plasm, a specialized cytoplasmic region containing polar granules. Components of these granules are also present in the perinuclear ring surrounding nurse cells, the nuage. Two such molecules are the Vasa and Tudor proteins. How Tudor localizes and is maintain...
During vertebrate egg maturation, cytokinesis initiates after one pole of the bipolar metaphase I spindle attaches to the oocyte cortex, resulting in the formation of a polar body and the mature egg. It is not known what signal couples the spindle pole positioning to polar body formation. We approached this question by drawing an analogy to mitotic exit in budding yeast, as asymmetric spindle a...
To test the "traction fiber" model for metaphase positioning of bivalents during meiosis, kinetochore fibers of maloriented bivalents, induced during recovery from cold arrest, were analyzed with a liquid crystal polarizing microscope. The measured birefringence retardation of kinetochore fibers is proportional to the number of microtubules in a fiber. Five of the 11 maloriented bivalents analy...
Motion planning and visibility problems are some of the most important topics studied in Computer Graphics, Computational Geometry and Robotics. There exits several and important results to these problems. We propose a new approach in this paper using a preprocessing in the plane, the polar diagram. The polar diagram can be considered as a plane tessellation with similar characteristics to the ...
We used video-light microscopy and laser microsurgery to test the hypothesis that as a bioriented prometaphase chromosome changes position in PtK1 cells, the kinetochore moving away from its associated pole (AP) exerts a pushing force on the centromere. When we rapidly severed congressing chromosomes near the spindle equator between the sister kinetochores, the kinetochore that was originally "...
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