ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02198.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02199.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02200.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.On weaning, pigs were placed in a house of a type which is commonly used for early weaning or individually in cages in a controlled environment room. Micro‐organisms (11,631 isolates) recovered from air, food, faeces, water and pigs' skins were characterized and identified at the genus level. Pigs in the controlled environment harboured populations of lactobacilli and haemolytic serotypes ofEscherichia coligreater than those of their littermates housed in a conventional piggery early‐weaning house. This was ascribed to the heavy faecal contamination of food in the troughs of the caged pigs, since the air in the controlled environment contained fewer micro‐organisms than that in the conventional piggery. The association of high numbers of faecal lactobacilli and haemolyticE. coli, and confinement in a controlled environment were not associated with the same amount of clinical disease and growth depression as was the combination of smaller numbers of the same organisms and conventional ho

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02201.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.Low concentrations of Zn and Co salts in the medium stimulated growth of several strains of 2 species ofLeptospira, but high concentrations inhibited growth. Low concentrations of Cu increased the growth rate of saprophytic leptospirae but did not affect parasitic strains; high concentrations inhibited all strains. In a Zn‐containing medium, the addition of increasing amounts of Cd was increasingly inhibitory to both speeies. The addition of 0·2 × 10−6gof Zn(NO3)2. 6H2O and 10−9gofCoSO4. 7H2O/ml of Korthof's medium is recommended. Saprophytic leptospirae grow better with 10−6g of CoSO4. 5H2O/ml

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02202.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.A method for counting viable anaerobic spores by roll tubes incubated in an atmosphere of hydrogen compared favourably with other techniques. Reproduction of environmental conditions in individual anaerobic jars did not significantly contribute to the overall error (Coefficient of Variation of viable count, 6·7%). Colony counts did not show a Poissonian distribution, and the significance of this is discussed. Optima for some conditions for counting 4 species ofClostridiumand for suspensions of spores ofCl. welchiidamaged by heat, γ‐rays or ethylene oxide have been established. Damaged spores were more exacting in their cultural requirements than were control organisms, and considerable variation in incubation temperature optima was found according to the sublethal treatment emplo

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02203.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.Viable counts of spores surviving exposure to bactericidal influences were higher in nitrogen than in hydrogen. The relationship between the nitrogen and hydrogen counts was dependent on the bactericidal pretreatment. Two species showed a cysteine dependence which was probably not due to its effect onEh. Low concentrations of carbon dioxide caused a reduction in count.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02204.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.The viable counting of bacteria in activated sludge has been investigated. The surface viable technique was considered satisfactory. The constituents of activated sludge appear to be nutritional requirements for some bacteria present. The deflocculating agents sodium pyrophosphate, sodium citrate and the nonionic surfactant, Lubrol W, facilitated the separation of bacteria from the particulate matter. A combination of sodium pyrophosphate and Lubrol W both at a concentration of 0·01% was very effective in this respect

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02205.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.The efficiencies of an ultrasonic cleaning tank (insonation) and a vortex stirrer for bacteriological sampling of foods were compared with a standard homogenization method. Insonation gave good recovery of micro‐organisms in a limited range of foods, and its main advantage was the very low debris content of the resultant suspension. Vortex stirring was a much more useful method for routine work, combining convenience and rapidity of sample preparation with low running costs, low noise level and easily pipettable suspensions. The high concentration of organisms obtained by vortex stirring may aid detection of low levels of contaminatio

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02206.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Summary.The enterocinogeny and lysogeny of enterococci was studied with a double layer agar method and 21 indicator strains of enterococci. Of 77 strains examined, 76 produced enterocine, and of 19 strains examined, 5 were sensitive to their own enterocine. All 77 strains were lysogenic when cultures killed with chloroform were examined for lysogeny by the method of Liegeois‐Müller&Fredericq (1952). By the same method, 4 of 7 strains were found to produce phages active against themselv

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1970.tb02207.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY