ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00697.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The growth of strains ofBacillus thiaminolyticuswas found to be inhibited by many other bacteria in glucose‐containing media. The properties of the substances responsible for the inhibition were such as to suggest that they could be carboxylic acids. Carboxylic acids were found to produce a similar inhibition ofB. thiaminolyticusand another thiaminase type I‐producing organism,Clostridium sporoge

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00698.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A new method for bacterial surface sampling meats is described. Using a cotton wool swab stick, bacteria are transferred directly to the surface of a segment (= 1/6) of an agar plate. After incubation, the number of colonies is estimated using a comparator disc, giving the result in point values of 1/3 of a log10‐unit. The average point value is then converted into the average number of colonies per segment using a Table. In order to emphasize that the results should be regarded as relative levels rather than actual bacterial counts, the result should be recorded as ‘bacteria/sample’—not ‘bact

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00699.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Proximate analyses of clarified rumen fluid No. 1 (CRF1) and No. 2 (CRF2). and of an aqueous extract ofEscherichia colicells are reported. Differences in the procedures for preparing CRF2 and CRF1 from the same batch of whole rumen fluid were reflected by increased levels of carbohydrate, protein and total nitrogen in CRF2. Variations in the composition of CRF2 with time after feeding are also reported. Results showed CRF2 to be an inconsistent and non‐reproducible medium supplement. The extract ofE. colicells contained very low levels of volatile fatty acids and ammonia and thus by itself could not replace CRF2 in medium for many species of rumen bacteria. It could be used as an alternative to CRF2 in media where more consistent and reproducible composition was required if the medium were supplemented with defined mixtures of nutrients known to be required by rumen bacteri

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00700.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The plaque‐producing properties ofStreptococcus sanguis, Streptococcus salivarius, Streptococcus mutans, Streptococcus mitisandStreptococcus faecaliswere investigated in an artificial mouth with continuous supply of nutrient. Attention was focused on the role of salivary factors and sucrose in tooth colonization. Plaque formation by single cultures depended on the ability to produce tenacious extracellular polysaccharide or to cohabit the tooth with an organism having this property. Sucrose was the only essential additive to nutrient broth necessary for plaque formation and could not be substituted by sterile natural saliva. Saliva neither facilitated colonization byStrep. mitisnor prevented colonization byStrep. salivariusas may have been supposed from previous report

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00701.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Growth ratesin vitroofPseudomonas syringaeandXanthomonas pruniwere measured over the temperature range 0–36 °C. The estimated temperature optimum forX. pruniwas 31 °C, with a doubling time of 1.53 h. The estimated temperature optimum forP. syringaewas 28 °C with a doubling time of 1.27 h, although analysis showed no significant difference in the doubling times over the range 23–33 °C, indicating an unusual plateau at the maximum rate of growth of this organism.P. syringaeand related plant pathogenicPseudomonasspp. grew well at low temperatures, butX. prunidid not. Cultures ofP. syringaeandX. prunihad a very short lag phase after their incubation temperature was changed from 4 °C to a temperature close to their optimum (29 °C). When the incubation temperature of these organisms was changed from 11.5–29 °C,X. prunigrew without a lag phase at the rate expected for the higher temperature. However, the initial growth rate ofP. syringaeat the higher temperature was significantly greater than that at which the organism subsequently developed. The ecological significance of these points is discussed. The usefulness of the Arrhenius coefficients as characteristics of these organisms

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00702.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Two outbreaks ofClostridium perfringensfood‐poisoning involving the same person were investigated. In the first, typical symptoms with diarrhoea and abdominal pain were observed. In the second, there were no classical signs of food‐poisoning; the victim felt some flatulence and the faeces had a pasty appearance and an unpleasant smell. Counterimmunoelectrophoresis and the reversed passive haemagglutination test were rapid and reliable assay methods for enterotoxin in faeces. In the first outbreak, 13–16 μg enterotoxin/g faeces were detected, and 3–4 μg/g in the second. The detection of enterotoxin in faeces indicates the potential use of enterotoxin tests on diarrhoeal samples for diagnosingC. perfringensfood‐poisoning. No enterotoxin was detected in serum during the acute stage of the illness, but the antibody titre showed a considerable rise in the first two months after the food‐poiso

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00703.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Presumptive coliform counts and the distribution ofEscherichia coliO‐serotypes were investigated in chicken rectal contents (175) abdominal cavities (152) and on the carcasses of 44 which had been commercially raised, slaughtered and prepared for sale. Large numbers ofE. coliresistant to at least one antibacterial agent were found at each site; comparison of the O‐serotypes suggested heavy contamination of the carcass with strains from the gut. The range of O‐serotypes was similar to that found in man and some public health implications of cross‐infection particularly by handling uncooked birds in the kitchen, are di

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00704.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Polyethoxyoctyl derivatives Triton X45 and Triton X100 induced leakage of cellular materials fromStaphylococcus aureus. The total leakage of 260 nm‐absorbing material, potassium (K+), amino acids and protein depended on the concentrations of surfactant, with K+loss occurring most rapidly. There appeared to be little quantitative correlation between loss of viability and leakage. It is suggested that leakage may reflect changes in membrane permeability resulting in the inability of cells to recover normal functions when placed in a growth‐supporting med

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00705.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Triton X45 and Triton X100 are antibacterial non‐ionic surfactants which bring about a considerable increase in the optical density (OD) ofStaphylococcus aureussuspensions and isolated cell walls. Both surfactants caused rapid lysis of sphaeroplasts, Triton X100 being the more effective lytic agent. It is proposed that the increases in the OD of cell suspensions occur principally as a result of changes in the reflective properties of cell wall

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1977.tb00706.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY