摘要:

‘Competitive exclusion’ treatment protected chicks against an environmental challenge withSalmonella enteritidisphage type 4, whether or not feed containing antimicrobial organic acids was also used. Treatment reduced the incidence ofSalmonella‐positive caecal samples from 82 to 8%, with a corresponding reduction in liver infection from 52 to 13%. Although acid‐treated feed had no influence on an environmental challenge with salmonellas, its compatibility with ‘competitive exclusion’ suggests an advantage in their combined use to maximize protection of poultry againstSalmonel

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00506.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A commercially available sensitized latex suspension could detect viable (102organisms/ml) or heat‐killedCampylobacter jejuni.Cross‐reactions with otherCampylobacterspp. andHelicobacter pyloriwere only seen with suspensions>105organisms/ml. In laboratory microcosms,C. jejuniremained viable for 16 d at 4°C but latex detected antigen for at least 6 months. In water from a sewagecontaminated lake, the latex gave results comparable with culture forC. jejunibut much more rapidly. Culture‐negative water supplies in chicken sheds containing campylobacter‐colonized birds were shown to be sometimes latex

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00507.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The ß‐galactosidase enzymes ofAspergillus oryzaeandScopulariopsissp. are secreted during growth of the fungi on polygalacturonic acid, but not during growth on a wide range of other substrates, including lactose. The enzymes are thermotolerant with temperature optima in the range 55–65°C. The results indicate that fungal extracellular ß‐galactosidases are involved in fungal growth on complex polysaccharides but not on

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00508.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

No significant differences in electrical conductance parameters were observed when multiple portions of animal proteins were examined for salmonella on three Malthus 2000 analysers. No differences were noted in the isolation rates from conductance tubes on the three analysers. Results also indicates the importance of examining multiple samples due to uneven distribution of organisms in a dry matrix.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00509.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Use of appropriately balanced immunological reagents and incubation of microslides at 45°C resulted in confirmed assay results in 6 h for staphylococcal enterotoxins. The sensitivity of the 45°C–6 h assay was comparable to the 37°C‐24 h assay: 0·1 μg of staphylococcal enteroto

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00510.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The conjugal transfer of recombinant plasmids into a gellan gum‐producing, rifampicin‐resistant strain ofPseudomonas elodeaand into one of its non‐producing variants, was studied in order to facilitate the cloning of gellan genes. The mobilization frequency of recombinant plasmids derived from pKT240, and of cosmid pJRD215 fromEscherichia coliHB101 (hsdM), into the mucoid strain was below the values for the non‐mucoid variant and decreased exponentially with plasmid size. Reducing the mating time on solid surfaces led to higher mobilization frequencies. Under optimal conditions, a gene bank (40–50 kb) constructed in the cosmid pJRD215 was efficiently mobilized into Gel‐mutants during complementation

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00511.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Thirty‐two samples ofceriche, a South American acidified fish product, were tested for the presence of listeria.Listeria innocuawas isolated from 24 samples (75%) andL. monocytogeneswas isolated from three samples (9%) of those teste

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00512.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Exponential phase cultures of a protease‐deficient and a protease‐proficient strain ofBacillus subtilis, growing in minimal medium with a glucose carbon source, were labelled with14C‐phenylalanine. Subsequent export of labelled protein was detected in trichloroacetic acid‐precipitated supernatant fluid samples. During exponential growth the strains exhibited substantially similar protein export kinetics. However, as confirmed by the presence of a cytoplasmic enzyme in the culture supernatant fluid, protease deficiency was associated with an increased tendency of cells to lyse as they approached stationar

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00513.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The partial 16S rRNA sequences of two unknown human enterococcal isolates were determined by reverse transcription in an attempt to clarify their taxonomic position. The sequence data indicate that they belong to a hitherto unknown species ofEnterococcus, for which the nameEnterococcus disparsp. nov. is proposed. The type strain is NCIMB 13000.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1991.tb00514.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY