ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00818.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00819.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Staphylococcus epidermidisand other organisms from the skin were found to be the commonest contaminants in 21 samples of human milk donated to a milk bank. Only 2 samples contained enterobacteria; no β‐haemolytic streptococci were isolated. Data presented show the difference between bacterial numbers in the first 10 ml and subsequent secretions of milk when drawn sequentially. Refrigerated storage led to the growth of some organisms in the milk; no growth occurred in milk stored at −18°C. A miniaturized resazurin dye test was devised but preliminary observations showed that it had a limited value in detecting rapidly milk of poor bacteriological qu

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00820.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

After negatively staining with 1% (w/v) sodium phosphotungstate (pH 6·5) or 1% (w/v) ammonium molybdate (pH 6·5), the cell wall, cytoplasmic membrane and mesosomes of the RSD‐associated bacterium obtained from the fibrovascular fluid of infected sugarcane were usually clearly displayed. The cells measured 0·19–0·39 μm (av. 0·27 μm) in width and 0·6–3·4 μm in length. Few mesosomes were visible and the cells were approx. 40% wider (0·27–0·52 μm, av. 0·38 μm) when stained with 1% (w/v) uranyl acetate (pH 3·0–4·2). Freezing and thawing the suspension before negative staining with sodium phosphotungstate did not greatly affect the size of the cells or resolution of the mesosomes. Glycine (0·25 M) as the suspending medium, fixation in 2% (w/w) glutaraldehyde, or placing wet instead of dry specimen grids in the electron microscope resulted in wider cell

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00821.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Water samples were collected from the Humber estuary at a site subject to pollution by metal refinery effluent.Vmax/bacterium for glucose mineralization, the percentage of glucose uptake by bacteria which was mineralized (%R) and dissolved copper concentrations were measured.Vmax/bacterium was negatively correlated with copper concentration and might be of use as an indicator of pollution stress. %Rwas not related to copper concentration and was not suitable as an indicator of pollution stress at this site.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00822.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Pullulan in a solid growth medium can be precipitated selectively with ethanol. Clear zones due to pullulan hydrolysis surround microbial colonies which produce the appropriate enzyme. When this procedure was applied to 297 strains representing 26 species of the genus Bacillus, 138 (46%) of the organisms were shown to hydrolyze pullulan.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00823.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Thirty‐one strains of streptococci, selected because they were considered to be or were similar toStreptococcus uberis, were examined by physiological tests and for properties of their lactate dehydrogenases (LDHs) and deoxyribonucleic acid (DNA). Twenty‐nine of the 31 strains fell into two main genotypes as judged by DNA/DNA hybridization. One genotype (Group I) included the type strain ofStrep. uberisand most other strains in this group were physiologically similar to it and had the same percent guanine + cytosine (%GC) in their DNA. The other genotype (Group II) contained strains which were more variable physiologically and had DNA of a lower % GC than the type strain. The European strains examined contained two distinct LDH types, one being associated with the Group I and the other with Group II strains. Three American strains examined however had LDH's which were unlike those of the European stra

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The measurement of electron transport system (ETS) activity in freshwater benthic and planktonic samples was examined. Significant improvements in sensitivity were obtained by increasing the concentration of substrates and of Triton X‐100 in the extraction buffer and by changing the buffer system. The mechanical homogenization procedures which have been used previously to extract the enzymes were shown to be inadequate yielding, at best, 25% of the activity obtained by ultrasonication. The yield of enzymes from sediments was greatly affected by the degree of dilution used and previously published methods would appear to be inadequate. ETS activity correlated well with biological oxygen uptake and, in individual water and sediment profiles, with microbial numbers and biomass. At a more general level, however, the ETS: biomass ratio showed considerable variatio

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00825.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Survival curves for conidiospores ofAspergillus flavusandA. terreussuspended in tissue culture medium containing 25% horse serum and different concentration of amphotericin B (as Fungizone) were compared. Dormant conidiospores were relatively insensitive. Conidiospores incubated in the absence of the drug became increasingly susceptible and the relationship between the duration of preincubation and numbers of conidia surviving consequent exposure to antibiotic was exponential. Of the two species,A. flavuswas much more sensitive to amphotericin thanA. terreusand in both species conidiospores harvested from young (4 d) cultures were much more sensitive than older conidia, harvested after storage for between 3 and 13 weeks. Variations in death rates for conidiospores of different ages and physiological states and the shapes of the survival curves are explained in terms of antibiotic penetration, pregermination events and germination inhibition.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00826.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

A microbiological quality control procedure requiring 9 tubes is described. It is designed so that (1) the probability of rejection exceeds 0·95 when the density of the organisms exceeds a specified critical level, (2) the probability of acceptance exceeds 0·95 when the density of the organisms is less than one‐fifth of this critical level, and (3) estimation of density is adequate over a reasonable range beneath this critical le

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1979.tb00827.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY