Cell, animal oocyte

Various types of cells can be scored for chromosomal aberrations. Spermatogonial cells, spermatocytes, oocytes, early embryos, bone marrow cells, and lymphocytes have been used successfully after in vivo treatments of an animal. For short-term cytogenetic analysis, however, an in vitro cell-culture assay is often chosen. Such in vitro assays usually use a peripheral lymphocyte system or a monolayer cell-culture system. 

Sagata N (1996) Meiotic mataphase arrest in animal oocytes its mechanisms and biological significance. Trends Cell Biol 6 22-28... 

The nucleoproteins of the nuclei of trout, salmon and herring sperm, are made up almost entirely of protamine and desoxyribonucleic acid. The nucleoproteins of thymus are made up of desoxyribonucleic acid (40%), ribonucleic acid (1-2%), histones and non-basic proteins. The cellular nuclei contain chiefly desoxyribonucleic acid but, in addition, there is a little ribonucleic acid (in the nucleolus and chromosomes). The cytoplasmic nucleoproteins in general contain only ribonucleic add assodated with proteins which do not have the basic properties of those joined to desoxyribonucleic acid. But the reproductive cell of animals (oocytes) contain desox5rribonudeic add in the cytoplasm. The desoxyribonucleic add of the chromosomes is combined with histones, protamines, and a protein of the usual t3rpe, which is referred to as residual protein. 

Chimeric DNA molecules are introduced into cells to make transfected cells or into the fertilized oocyte to make transgenic animals. 

The best evidence of hydrocarbon transfer into cells is with oocytes. Oocyte development in cockroaches, as in most oviparous animals, is characterized by a dramatic growth period during which all maternally derived macromolecules are sequestered. Vitellogenin uptake by the oocyte has been extensively studied... 

MEIOSIS The process by which a eukaryotic cell nucleus (in which the DNA has been replicated only once) undergoes two coordinated divisions that yield four cells, each having ploidy half that of the original cell in higher animals, meiosis provides for the production of haploid sperms or eggs from diploid spermatocytes or oocytes. (See also MITOSIS)... 

The intraperitoneal administration of mercuric chloride at levels comparable to those described above did not induce a clastogenic response in the spermatogonia of the same mouse strain (Poma et al. 1981). Structural chromosome aberrations were not produced in metaphase II oocytes of 15 virgin Syrian hamsters receiving a single intraperitoneal injection of 7.4 mg Hg/kg as methylmercury chloride (Mailhes 1983). However, the frequency of hyperploid cells in the treated animals was significantly (p<0.01) increased compared to the control. A borderline significant increase in hypoploid cells was also seen. 

Since there is an absence of reports detailing the activation of human SCNT oocytes and the successful production of cloned blastocysts, it was necessary to identify several parameters, including the reprogramming time (the time between cell fusion and egg activation, returning the gene expression profile of the somatic cell to that needed for appropriate embryonic development) and activation methods. Based on results from animal SCNT oocytes and the parthenogenetic activation of human oocytes, we initially employed a porcine activation protocol (simultaneous fusion and activation with electrical pulse) which used hu-... 

Cryptosporidia are protozoan parasites that cause diarrhea in many species, including humans. Cryptosporidium parvum and C. hominis account for almost all human infections. Infectious oocysts in feces may be spread either by direct human-to-human contact or by contaminated water supplies. Groups at risk include travelers, children in day-care facilities, male homosexuals, animal handlers, veterinarians, and other healthcare personnel. Immunocompromised individuals are especially vulnerable. After ingestion, the mature oocyte releases sporozoites that invade host epithelial cells. Infection usually is self-limited. In AIDS patients and other immunocompromised individuals, severe secretory diarrhea may require hospitalization and supportive therapy. 

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