Biomedical subjects
Publications and source records attributed to S Shivaji.
Ten cultures of Pseudomonas spp. were established from soil samples collected in and around a lake in Antarctica. Based on their morphology, biochemical and physiological characteristics, and moles percent G + C of their DNA, they were identified as P. fluorescens, P. putida, and P. syringae. This is the first report on the identification of Pseudomonas spp. from continental Antarctica.
Using IgG antibodies raised against RNA-A BS1, the presence of this seminal RNA-A on the surface of bovine spermatozoa has been demonstrated. Indirect immunofluorescence and immunoferritin methods showed that this protein coats the surface of ejaculated bovine spermatozoa, but the pattern of binding of the label varied from cell to cell. More than 50% of the spermatozoa showed labelling all over, except the anterior head region; about 30% showed labelling all over except the region below the equatorial plate region; and the remaining were either completely labelled or showed labelling only in the head or the tail region. The head-tail junction (the neck region) was not labelled in any case.
Proteins present in the seminal plasma of mammals are known to influence functions associated with ejaculated spermatozoa such as motility, capacitation, acrosome reaction and fertilising ability. The proteins isolated and characterised so far influence only one of the above functions of spermatozoa. Seminalplasmin, a protein isolated from the seminal plasma of bull is exceptional in that it influences many of the above spermatozoal functions. It is also a potent antimicrobial protein and capable of lysing microbial and mammalian cells. The physiological function of seminalplasmin as nature's own antifertility agent is discussed.
The interaction of seminalplasmin with chlortetracycline, a fluorescent chelate probe of Ca2+, was studied. The results indicate that seminalplasmin binds to chlortetracycline. The binding is not influenced by salt. Both Ca2+ and seminalplasmin probably bind to the same site on chlortetracycline. Seminalplasmin also reduced the Tb3+-associated fluorescence of bovine spermatozoal plasma membrane. These results are discussed in relation to the inhibitory effect of seminalplasmin on the uptake of Ca2+ in bovine spermatozoa.
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The binding of seminalplasmin, a protein secreted by the accessory sex glands of bull, to the plasma and outer acrosomal membrane of bovine spermatozoa was studied using three different fluorescent probes. 8-Anilino-1-naphthalenesulfonate fluorescence, pyrene excimer fluorescence and diphenylhexatriene fluorescence polarisation studies indicate that seminalplasmin binds to the spermatozoal membranes, and leads to an increase in the fluidity of both the plasma and the acrosomal membranes. Calcium was found to have no influence on the interaction of seminalplasmin with the spermatozoal membranes. These results suggest that protein(s) present in the seminal plasma could interact with spermatozoal membranes and increase their fluidity.
Seminalplasmin, an antimicrobial protein present in bovine seminal plasma, is shown to inhibit the growth of, as well as nucleic acid and protein synthesis in, wild-type Saccharomyces cerevisiae SM202, when used at concentrations greater than 200 micrograms/ml, in contrast to 20 micrograms/ml that is sufficient for Escherichia coli. An osmotically labile strain of S. cerevisiae VY1160 is 1-2 orders of magnitude more sensitive to seminalplasmin than the wild-type strain. RNA synthesis in protoplasts and nuclei of S. cerevisiae SM 202 was also about as sensitive to seminalplasmin as in E. coli and S. cerevisiae VY1160. The RNA polymerases I and II from S. cerevisiae were strongly inhibited by seminalplasmin in vitro, while DNA and protein syntheses were not affected by seminalplasmin in cell-free systems, unlike in the whole cells. It is concluded that seminalplasmin acts in S. cerevisiae by entering the cells and inhibiting transcription.
We show here the presence of an integral, strong RNAase-A-like ribonucleolytic activity in the plasma and outer acrosomal membranes of bovine spermatozoa. A part of this activity is extractable by salt or detergent.
Using immunoglobulin G (IgG) antibodies raised against highly purified, homogeneous seminalplasmin, an antimicrobial protein of bovine seminal plasma, it has been shown that bovine ampullae, gland vesicularis and corpus prostate, but not testes and epididymis, contain seminalplasmin. The content as estimated by radioimmunoassay employing 125I-seminalplasmin was: ampullae, 267 +/- 13; gland vesicularis, 275 +/- 14; and corpus prostate, 445 +/- 22 micrograms per g wet weight of the tissue. Seminalplasmin, as characterized by high-performance liquid chromatography and in vivo inhibition of RNA synthesis in E. coli, was isolated from gland vesicularis. The seminalplasmin content of bovine seminal plasma was shown to be 1%. A chymotryptic peptide of seminalplasmin comprising residues 1-13 from the amino terminus was found to compete with 125I-seminalplasmin for binding to anti-seminalplasmin IgG.
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Explore the source record for details and available documents.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.