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1.
V. Cencora F. Challoner S. Gooch A. Livingstone D. Widgery 《BMJ (Clinical research ed.)》1988,297(6646):481-483
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Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
相似文献
4.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
5.
J. H. Gooch R. A. F. Harcourt J. F. R. Ibbetson D. A. Whitmore 《BMJ (Clinical research ed.)》1972,3(5824):456-459
Analysis of work done by the secretaries attached to one medical unit in a general hospital showed that much was discretionary in character and entailed making decisions. Work in the unit was made easier and more efficient by this intelligent use of initiative by the secretaries. At present the pay given to medical secretaries in hospital is below a level that would be commensurate with their responsibility. 相似文献
6.
Phillip A Patten Russell J Howard Willem PC Stemmer 《Current opinion in biotechnology》1997,8(6):724-733
DNA shuffling is a practical process for directed molecular evolution which uses recombination to dramatically accelerate the rate at which one can evolve genes. Single and multigene traits that require many mutations for improved phenotypes can be evolved rapidly. DNA shuffling technology has been significantly enhanced in the past year, extending its range of applications to small molecule pharmaceuticals, pharmaceutical proteins, gene therapy vehicles and transgenes, vaccines and evolved viruses for vaccines, and laboratory animal models. 相似文献
7.
Under constant conditions, the circadian bioluminescent glow rhythm in populations (105 cells) ofGonyaulax polyedra is accurate to within 2 min/day. On successive days following the transfer to constant conditions, however, the glow exhibits a progressively broader waveform, implying that individual clocks in the population are drifting out of synchrony. Analysis of the glow waveform suggests that the standard deviation in circadian period among individual clocks is about 18 min and that the period of a given clock varies by less than this from one day to the next. 相似文献
8.
Inhibition by sodium chloride of the growth of 19 strains ofLegionella pneumophila and of 10 strains of otherLegionella spp. was studied. Results from growth in buffered -ketoglutarate cysteine yeast extract (BAYE) broth containing 0 to 2.0% sodium chloride indicated that 15/19 laboratory strains ofL. pneumophila were capable of growing in 1.0% to 1.5% sodium chloride, whereas 4 strains ofL. pneumophila and 10 strains of 6 other species were not.L. micdadei andL. longebeachae were the most inhibited in BAYE broth, growing only in concentrations of 0.5% sodium chloride. These in vitro studies indicate thatL. micdadei andL. longbeachae might be differentiated from other species by their low tolerance to salt in BAYE broth, and thatL. pneumophila may be more tolerant to salt concentrations found in brackish water environments. 相似文献
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Keyhole limpet hemocyanin (KLH)-primed lymph node cell (LNC) populations were incubated with various amounts of KLH and the cellular incorporation of tritiated thymidine ([3H]TdR) or tritiated N6, O2′ dibutyryl cyclic AMP ([3H]DbcAMP) was determined. T LNC responded more vigorously than did complement receptor lymphocytes (CRL), i.e., B cells, at all KLH concentrations, during all time intervals examined, and in the presence or absence of normal rabbit serum (NRS). The depletion of adherent cells from KLH-primed LNC resulted in no significant decrease in KLH-induced incorporation of either [3H]TdR or [3H]DbcAMP in any of the LNC populations. Thus it appeared that variation among LNC populations in the incidence of macrophages did not account for the marked variation in their responses. Cultures containing equal numbers of T and CRL were induced to incorporate more [3H]TdR or [3H]DbcAMP than either population cultured separately or the sum of their individual responses. It was concluded that KLH-induced incorporation of these substances into primed, isolated LNC, was primarily manifested in the T-cell population. The synergism seen in cultures containing mixtures of T and CRL suggested that B cells are induced to incorporate [3H]TdR or [3H]DbcAMP in the presence of antigen and T-cell product(s). KLH-induced incorporation of [3H]TdR into KLH-primed LNC was inhibited by cholera enterotoxin (CT) and DbcAMP as previously reported. However, CT or DbcAMP inhibited this incorporation into T LNC to a greater extent than into CRL or unfractionated LNC. 相似文献