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991.
The Nature of Induced Exchanges between the Attached-X and Y Chromosomes in Drosophila Melanogaster Females 总被引:1,自引:1,他引:0 下载免费PDF全文
John C. Lucchesi 《Genetics》1965,51(2):209-216
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BIOSYNTHESIS OF COLLAGEN AND NON-COLLAGEN PROTEIN DURING DEVELOPMENT OF THE CHICK CORNEA 总被引:3,自引:2,他引:1 下载免费PDF全文
The relationship between the rates of increase of corneal protein fractions and incorporation of labeled precursors has been examined during embryonic and early posthatching development of the chick corneal stroma. Non-collagen protein increased gradually from 9 through 20 days of incubation. Collagen accumulated approximately logarithmically through the 19th day, the most rapid rate occurring between 13 and 20 days of incubation. The rates at which labeled amino acids are incorporated into collagen in vivo and in vitro undergo marked changes during the last week of embryonic development, corresponding closely to the rate of collagen accumulation in vivo; whereas incorporation into non-collagen protein changes much less markedly. Changes in the rate of incorporation of precursors into collagen are not due to changes in the rate of conversion of collagen from the soluble to insoluble form, or to changes in the endogenous amino acid pool size. Chick embryo corneal stroma collagen turns over very slowly, if at all. Non-collagen protein turns over more rapidly. An increase in cell number, as indicated by DNA content, does not account for the increased rate of collagen synthesis between the 9th and 16th day of incubation. It is concluded that the observed changes in collagen synthesis reflect changing activities in the individual cornea fibroblasts. These activities are comparable in the intact tissue in vivo and in isolated corneas in vitro. 相似文献
996.
LOCALIZATION OF A BASIC PROTEIN IN THE MYELIN OF VARIOUS SPECIES WITH THE AID OF FLUORESCENCE AND ELECTRON MICROSCOPY 总被引:6,自引:3,他引:3 下载免费PDF全文
In this study, alanine was shown to be the N-terminal amino acid of a basic protein of low molecular weight that was isolated from either human or guinea pig brain. Antibodies prepared against the guinea pig protein were labeled with either fluorescein or ferritin. Studies with the labeled antibodies showed that an immunohistochemically similar protein is found in the myelin sheaths of central and peripheral nervous tissues of chicken and frog and a variety of mammalian species. Loss of integrity of the myelin during processing was shown to enhance markedly the antigen-antibody reaction. 相似文献
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The Intracellular Localization of Hormonal Activity in Transplantable Thyrotropin-Secreting Pituitary Tumors in Mice 总被引:1,自引:0,他引:1 下载免费PDF全文
Virendra B. Kamat Donald F. Hoelzl Wallach John F. Crigler Jr. Aaron J. Ladman 《The Journal of cell biology》1960,7(2):219-226
Mouse pituitary tumors secreting almost exclusively thyroid stimulating hormone have been characterized electron microscopically. Tumors of known thyrotropin content were separated into nuclear, mitochondrial, microsomal, and soluble fractions by differential centrifugation. The hormonal activity of these fractions was correlated with that of the total homogenates and with their nitrogen and phosphorus content. Essentially all the thyrotropin of the homogenate was recovered in a particulate fraction sedimenting between 20,000 and 40,000 g. This fraction contained the RNA granules and membranous components typical of microsomal pellets, but also showed the presence of small dense bodies surrounded by smooth membranes. These bodies were also visible within the endoplasmic reticulum of intact cells, and it is postulated that these bodies may represent the sites of intracellular elaboration and/or storage of TSH. Thyrotropin is tightly associated with microsomal particles but can be brought into solution by treatment with alkaline media, deoxycholate, and certain organic solvents. 相似文献
1000.
EFFECT OF INCUBATION TEMPERATURE ON BIOCHEMICAL TESTS IN THE GENERA PSEUDOMONAS AND ACHROMOBACTER 总被引:1,自引:0,他引:1 下载免费PDF全文
John A. Alford 《Journal of bacteriology》1960,79(4):591-593