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991.
K. F. Jarrell Tatiana Vydykhan Peter Lee M. Dorothy Agnew Nikhil A. Thomas 《Extremophiles : life under extreme conditions》1997,1(4):199-206
The isolation and characterization of a novel bacteriophage active against the obligately alkaliphilic bacterium Bacillus clarkii is described. The bacteriophage, designated BCJA1, is a member of the Siphoviridae family with a B1 morphology. It possesses
an isometric head, which measures 65 nm between opposite apices, and a noncontractile tail of 195 nm length. It had a buoyant
density of 1.518 g/ml and an estimated particle mass of 37 × 107 daltons. BCJA1 was stable over the pH range of 6–11. A one-step growth experiment conducted at pH 10 demonstrated a latent
period of about 40 min and a burst size of approximately 40. The purified bacteriophage appeared to consist of 10 proteins
with the major head and tail proteins likely to be of molecular weight 36 500 and 28 000, respectively. The genome size was
estimated to be between 32.1 and 34.8 kb. The percent G + C content of purified bacteriophage DNA was 45.6. The wildtype bacteriophage
is temperate but a clear plaque mutant was isolated.
Received: May 25, 1997 / Accepted: August 5, 1997 相似文献
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Dorothea L. Sawicki Sam M. Beiser Dorothy Srinivasan P.R. Srinivasan 《Archives of biochemistry and biophysics》1976,176(2):457-464
The ability of specific antibodies to react with 7-methylguanine residues in nucleic acids was investigated. Anti-7-methylguanine specific antibodies precipitated polymers of poly-guanylic acid which were methylated to an extent of 35 or 70% at the N-7 position of guanine, indicating that these antibodies could readily detect 7-methylguanine residues in a polynucleotide. This reaction was proportional to the total amount of 7-methylguanine present, suggesting further that quantitation of these residues is possible. To determine the minimal amount required for detection, varying amounts of 7-methylguanine were introduced into calf thymus DNA by alkylation with dimethyl sulfate. While showing no reaction with denatured nonalkylated DNA, the reaction of antibodies with alkylated DNA was proportional to the amount of 7-methylguanine in the preparations. Moreover, the antibodies appeared to detect differences in the distribution of 7-methylguanine residues in extensively methylated DNA. Precipitation was observed with DNA containing as little as one 7-methylguanine residue per 300 nucleotides, suggesting that these antibodies can be used to detect biologically significant levels of 7-methylguanine in viral and cellular nucleic acids. 相似文献
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