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71.
A. R. Slabas  C. G. Smith 《Planta》1988,175(2):145-152
Immunogold labelling was used to study the distribution of acyl carrier protein (ACP) in Escherichia coli and a variety of plant tissues. In E. coli, ACP is distributed throughout the cytoplasm, confirming the observation of S. Jackowski et al. (1985, J. Bacteriol., 162, 5–8_. In the mesocarp of Avocado (Persea americana) and maturing seeds of oil-seed rape (Brassica napus cv. Jet Neuf), over 95% of the ACP is localised to plastids. The protein is almost exclusively located in the chloroplasts of leaf material from oil-seed rape. Approximately 80% of the gold particles associated with the ACP were further localized to the thylakoid membrane of the chloroplast. Since acetyl-CoA carboxylase has been reported to be localized to the thylakoid membrane (C.G. Kannangara and C.J. Jensen, 1975, Eur. J. Biochem., 54, 25–30), these results are consistent with the view that the two sequential enzymes in fatty-acid synthesis are in close spacial proximity.Abbreviations ACC acetyl CoA carboxylase - ACP acyl carrier protein - FAS fatty-acid synthetase  相似文献   
72.
Summary Phenotypic analyses of genetic combinations involving the gene extramacrochaetae (emc) reveal its participation in the differentiation of both sensory elements and wing veins. The study of near-amorphic alleles of emc in mitotitc recombination clones indicates that it also affects cell proliferation. These clones show abnormal sizes, shapes and spatial distribution. They differentiate extra sensory elements as well as extra veins. A gain of function mutation in the gene causes opposite phenotypes in both differentiation systems. The effects of the mutant on proliferation and patterning are consistent with the emc gene being involved in the transfer of information between neighbouring cells, which leads to the spatial expression of the achaetescute gene complex and genes involved in vein formation.  相似文献   
73.
The article presents the review of modern data of the field and laboratory investigations of primate sexual behavior, cyclicity, reproductive strategies and copulation in different primates taxa: strepsirrhini, platyrrhyni, catarrhini. The specific character, progressiveness and adaptation of some reproductive models are discussed by the authors. A problem of connection between dominance and reproductive success is also discussed, the role of sexual teaching in postnatal ontogenesis, age and hormonal status for expression of sexual behavior are analysed. Some forms of sexual declinations in primates are considered.  相似文献   
74.
75.
Adherence to these principles will not guarantee success, but the testimony of many famous scientists supports the hypothesis that these guidelines can significantly (p less than .05, Wilcoxon unpaired X-test run at pH 5.6) increase your chances of achieving recognition, acquiring wealth, and ultimately being known as a successful scientist. At the very least, they should prevent you from falling too far outside the boundaries of "normal" science where you could easily be branded for life as a troublemaker or heretic.  相似文献   
76.
Alexandra Dane Dor-Ner ("Ali" to friends) was a photographer, writer, and a producer of programs on child development. In February 1989, at the age of 41, she was diagnosed with malignant brain cancer. During the following months she underwent brain surgery, radiation, and implant radiation. Throughout her treatment, she continued to work on a novel and write stores and literary criticism. A volunteer in hospitals before her illness, she now became very active in a support group of brain tumor patients and often served as a first resource and contact for others diagnosed with brain cancer. All was very accomplished; her award-winning photographs have been exhibited in the Smithsonian Institution in Washington, and her articles and pictures were published in books, periodicals, and newspapers around the world. A native of Boston, Ali lived for 17 years in Israel, where she joined a group of photographers documenting disappearing neighborhoods in Jerusalem. She was awarded first prize in the "Israel Through the Camera''s Eye" competition in 1977. She also taught English and photography in Israeli high schools. Ali traveled extensively on photographic assignments. Early in their 22-year marriage, she and her husband circumnavigated the globe on a freighter, producing a documentary film of the voyage. "Memoirs of an Amnesiac" was written while Ali was a student at the Warren Wilson College Writers'' Program in North Carolina; she intended to explore the compensatory aspects of her disease. In February 1991, within days of completing the piece, Ali had a third brain operation to remove a regrowth of cancerous tumor cells, as well as necrotic tissue. Two days later, she was again operated on to remove blood clots resulting from the previous surgery. For the next 12 weeks she fought to regain her ability to walk, talk, and write. In May, she underwent a fifth operation to relieve pressure in the brain. She was still in the hospital when she learned, to her great pleasure, that she would be awarded a master of fine arts degree from Warren Wilson College. She died on June 19, 1991.  相似文献   
77.
The method of separation of germ layers of rodent embryos by treating the embryonic shields with proteolytic enzymes and by microsurgery with the subsequent transplantation to ectopic sites has helped to gain a more detailed insight into what is going on during gastrulation in mammals. The space under the kidney capsule of adult animals seems to be the most appropriate ectopic site for transplantation of early postimplantation rat embryos or separated germ layers. After transplantation the grafts develop into teratomas whose complex histological structure reflects the initial developmental capacities of the graft. At the pre-primitive streak and the early primitive streak stages the primitive ectoderm differentiates into tissue derivatives of all three definitive germ layers, often in complex organotypic combinations. This is indirect evidence that all cells of the embryonic body originate from the primitive embryonic ectoderm. Halves of the primitive ectoderm obtained by a longitudinal or transverse cut through the egg cylinder give the same result. At the head fold stage the capacity for differentiation of the ectoderm is restricted to ectodermal and mesodermal derivatives. One day before gastrulation the isolated primitive ectoderm is not able to differentiate as renal isograft. The mesoderm isolated at the head fold stage and at later stages when its segmentation occurs, differentiates almost exclusively into the brown adipose tissue. The embryonic endoderm differentiates only in combination with the mesoderm. After transplantation the embryonic ectoderm loses its epithelial organization and breaks up into a mass of mesenchyme-like cells in which epithelial structures subsequently appear and differentiate in a way reminiscent of the reaggregation of cells in mixed cell suspension in vitro.  相似文献   
78.
An indirect enzyme-linked immunosorbent assay (ELISA) was used to determine levels of IgG reacting with lipopolysaccharide from Salmonella enteritidis in samples of egg yolk from broiler breeder and egg-laying flocks, some of which were known to be infected with S. enteritidis. There was positive correlation between infection with salmonella and a high reading in the ELISA.  相似文献   
79.
Investigations were carried out on the effects of Penicillium digitatum and Fusarium oxysporum on the nutritional value of pawpaw (Carica papaya). Decreases were observed in ash content, phosphorus, sodium, reducing sugars and ascorbic acid levels of fruits infected with P. digitatum, but increases in calcium and potassium content. In fruits infected by F. oxysporium, there were decreases in phosphorus, calcium, sodium ascorbic acid and reducing sugar levels; but the levels of ash content increased. The total protein level increased in the fruits infected with both fungi. These results revealed a reduction in fruit quality.  相似文献   
80.
Adrenergic innervation of the cerebrospinal arteries in redeye, frog, tortoise, hen, sea-gull, guinea-pig, rabbit, cat, dog and man has been studied by means of fluorescent-histochemical method. In all the animals there is a similar principle of innervation. The nervous apparatus is revealed as continuous integral plexuses. In the process of historical development the role of the nervous factor in regulation of the cerebrospinal circulation is increasing. As the innervational degree of the spinal arteries decreases, the vertebrates make the following line: mammals, birds, reptiles, amphibia, fishes. In all the animals, besides the fishes, the greatest concentration of the nervous fibers is revealed in the areas of the spinal cord thickenings.  相似文献   
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