摘要:

Antigenic analysis of human coronavirus, strain 229E (HCV/229E), using a microimmunodiffusion technique, has resulted in the detection of six virion antigens. Comparison of the effect of several different virus-disrupting agents has shown that sodium deoxycholate or Triton X-100 were the best for HCV/229E disruption. Of the six coronavirion antigens, three were identified as virus specific and the remainder as host antigens, which were present as either integrated or nonspecifically adsorbed host components. One of the virus-specific antigens was identified as the internal nucleoprotein (229E/RNP). On the basis of immunodiffusion reactions with isolated 229E/RNP it was concluded that human convalescent sera reacted specifically with the 229E/RNP antigen.

ISSN:0008-4166    

DOI:10.1139/m81-051

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Citrobacter freundiifrom an environmental source displayed resistance to a wide variety of antibacterials. Some of these resistances could be transferred by conjugation with frequencies as high as 10−2. The complexity of plasmid involvement in the antibacterial resistance of this species was demonstrated by isolation of plasmid DNA from two isolates. In one strain, resistance to β-lactam antibiotics was specified by a 55 × 106molecular weight plasmid, whereas kanamycin and neomycin resistance was specified by a 7 × 106molecular weight plasmid. Resistance to chloramphenicol and tetracycline was not plasmid mediated. The other strain contained plasmids of molecular weight 113 × 106and 80 × 106, which specified resistance to chloramphenicol, neomycin, kanamycin, tetracycline, and mercury.

ISSN:0008-4166    

DOI:10.1139/m81-052

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Studies of the marine bacteriumAlteromonas haloplanktis214 (formerly referred to as marine pseudomonad B-16) showed that as the Na+concentration in the growth medium decreased from 230 to 34 mM, the lowest concentration permitting growth, the length of the lag period preceding exponential growth increased. Once growth had begun, except for a slight reduction in rate of growth at 34 mMNa+, the generation time and extent of growth remained essentially constant over the range of Na+concentrations tested. Plate counts showed that during the lag period the numbers of viable cells introduced as inoculum into a complex medium containing 33 mMNa+decreased exponentially before increasing. Repeated subculture of the cells at 33 mMNa+failed to eliminate the lag period or reduce the loss of viability of the cells. The viability loss and the lag period could be eliminated either by raising the NaCl concentration to 130 mMor by adding sufficient sucrose to make the osmotic pressure of the medium equal to that obtained by adding 130 mMNaCl. In a chemically defined medium, sucrose added to maintain tonicity reduced but did not eliminate the lag periods obtained at suboptimal Na+concentrations. Increasing the number of cells plated on trypticase agar medium reduced the Na+concentration required to permit growth. Evidence was obtained of a requirement ofA.haloplanktisfor Ca2+for growth. Ca2+spared to a small extent the requirement for Na+for growth. Some 1010cells of a histidine-requiring, streptomycin-resistant mutant ofA.haloplanktis214, still viable after treatment withN-methyl-N′-nitro-N-nitrosoguanidine, were screened for capacity to grow in the absence of Na+. Since no non-Na+-requiring mutants were isolated, the requirement of this organism for Na+would appear to be extremely stable.

ISSN:0008-4166    

DOI:10.1139/m81-053

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Cells of a histidine-auxotrophic, streptomycin-resistant mutant of marine bacteriumAlteromonas haloplanktis214 were grown at or near the lowest concentration of Na+permitting growth (30–33 mMNa+). When suspended in solutions containing 10 mMKCl and either 30, 100, or 300 mMNaCl, the intracellular to extracellular K+ratios after equilibration were found to be 11.6, 20.8, and 43.2, respectively. The corresponding Na+ratios were 1.0, 0.46, and 0.62. The K+ratios were similar to those obtained with cells of the parent organism grown at more nearly optimum Na+concentrations, whereas the Na+ratios were somewhat larger. Cells of the parent organism grown at 32 mMNa+transported α-aminoisobutyric acid (AIB) at only one-third the rate and to less than one-quarter of the extent of cells grown at 130 mMNa+even when the NaCl concentration during transport was raised to optimum levels. TheKmfor uptake of AIB by cells grown at 32 and 130 mMNa+was the same but theVmaxwas higher for cells grown at 130 mM. TheVmaxfor cells grown at both concentrations of Na+increased as the Na+concentration in the uptake medium increased. It was concluded that none of the observations made could account for the fact that both parent and mutant ofA.haloplanktisgrow at 30–32 mMNa+only after a very long lag period, and then grow at near normal rates once logarithmic growth begins despite the fact that the osmotic pressure of the medium is very low.

ISSN:0008-4166    

DOI:10.1139/m81-054

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The zymogram technique has been applied to three pathotypes of the entomopathogenic fungusNomuraea rileyi. Isozyme profiles of isolates fromHeliothis zea,Pseudoplusia includens, andAnticarsia gemmataliswere compared for 17 enzymes of known metabolic function. Electrophoretic data supported the taxonomic differences inferred for the three pathotypes based on host specificity. The isolate fromA.gemmataliswas found consistently to be the most distinct.This study demonstrates that isozyme analysis may be used to distinguish closely related fungal isolates ofN.rileyi.

ISSN:0008-4166    

DOI:10.1139/m81-055

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A diploid strain (D1) ofAspergillus niger(V35) was isolated following heterokaryosis between two morphological mutants. Compared with wild type and the parent strains, the diploid strain showed increased DNA content, O2uptake, and succinic dehydrogenase activity.

ISSN:0008-4166    

DOI:10.1139/m81-056

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A microhemagglutination procedure, using fibrinogen-coated erythrocytes of rabbit or pig for quantitation of staphylocoagulase, is shown to be more sensitive than the standard tube test.

ISSN:0008-4166    

DOI:10.1139/m81-057

出版商:NRC Research Press    

年代:1981

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m81-058

出版商:NRC Research Press    

年代:1981

数据来源: NRC