摘要:

W.J. DORSA, C.N. CUTTER AND G.R. SIRAGUSA. 1996. Six bacterial sampling methods that might be used for rapid sampling of beef carcasses were evaluated in two separate studies. In Study 1, bacterial recovery from uninoculated beef rounds was 2.6, 2.3, 2.1 and 1.3 log10cfu cm‐2, respectively for excision (EX), and swabbing with cheesecloth (CC), sponge (SP) and cotton‐tipped wooden swabs (CS). For Study 2, beef tissue was inoculated with bovine faeces at different levels and the mean recovery was 3.7, 3.0, 3.1 and 3.1 log10cfu cm‐2, respectively for EX, and swabbing with SP, griddle screen (GS) and 3M mesh (M). For both studies EX was determined to be the most consistently effective method while the initial study determined swabbing with CS was the least effective of the methods used. In both studies the most abrasive materials approached the effectiveness of EX even at low inoculation levels. As the inoculation levels increased, the additional effect of abrasiveness was lessened. When the carcasses were contaminated with bovine faeces, the bacterial populations that were rapidly recoverable from beef tissue using SP, GS or M were not significantly lower than those recovered using EX. Consequently SP, GS or M are an adequate method of beef carcass sampling for rapid, in‐plant process monitoring to detect faecal contam

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01104.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

DAI JINGYUAN, YU LING, WANG BO, LUO XIXIA, YU ZINIU AND M.‐M. LECADET. 1996. Two isolates (YBt‐981 and Ybt‐978) ofBacillus thuringiensiswere isolated from soil samples from Shanxi and Neimeng provinces in China. The isolates produced small and irregular parasporal inclusions that were not toxic to larvae ofCulex fatigans, Culex pipiens, Anopheles sinensis, Aedes aegypti, Spodoptera littoralis, Spodoptera exigua, Plutella xylostellaandBombyx mori. H‐antigens from isolates of YBt‐981 and YBt‐978 differed from those of the knownB. thuringiensisH1 to H39 serotypes. YBt‐981 and YBt‐978 had the same H‐antigens and the same biochemical characters. The two isolates were identified as a new serotype designated H40. The name ofB. thuringiensisserovarhuazhongensisfor this new subspecies represented by YBt‐981 and

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01105.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

J. KWANG, E.T. LITTLEDIKE AND J.E. KEEN. 1996. A primer set of oligonucleotides (S18 and S19) from theompCgene ofSalmonellahas been evaluated for specific detection of Salmonella by polymerase chain reaction (PCR). This primer set successfully amplified 40 Salmonella serovars (60 isolates), but not 24 non‐Salmonella bacteria (42 isolates) that have been tested so far. The uniqueness of these primer sequences was also confirmed. The sensitivity of PCR detection in extracted chromosomal DNA forSalm. typhimuriumwas 1 pg. The sensitivity for boiled whole bacteria was 400 cells. The detection ofSalm. typhimuriumin ground beef samples required 4–6 h enrichment with an initial inocula of 100 bacte

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01106.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

M. GILMOUR, W.J. MITCHELL AND H.J. FLINT. 1996. Matings between the lactate‐utilizing, tetracycline‐sensitiveSelenomonas ruminantiumstrains 5521Cl and 5934e and the lactate‐non‐utilizing, tetracycline‐resistant strain FB322 resulted in putative recombinant strains capable of growth on lactate. Analysis of total protein by SDS‐PAGE and chromosomal DNA by hybridization, indicated that the recombinants were derived from strain FB322. DNA hybridization produced no evidence that plasmid transfer occurred, leaving chromosomal DNA transfer as the most likely mechanism for the altered phenotype. Analysis of strains 5934e, FB322 and the resulting recombinant TC3 indicated that all three strains contained D‐nLDH and L‐nLDH activities. In addition strains 5934e and TC3 possessed D‐iLDH activity when grown on DL‐lactate. The ability of strain FB322 to grow on pyruvate but not lactate suggested that the lactate‐utilizing recombinant had acquired the ability

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01107.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

R.J. ROWBURY AND N.H. HUSSAIN. 1996.Escherichia colitransferred from pH 7.0 to pH 5.5 or 6.0 became alkali‐sensitive by a rapidly induced phenotypic response. Alkali sensitization was reduced at pH 5.0 and virtually abolished at pH 6.5. The response was triggered by cytoplasmic rather than external or periplasmic acidification andde novoprotein synthesis was needed. Alkali sensitivity failed to appear at pH 5.5 plus DNA gyrase inhibitors and was markedly reduced byhimA, himD, hns, ompCandnhaAlesions.A tonBdeletion mutant showed alkali sensitivity at pH 7.0. Alkali sensitivity induction was not subject to catabolite repression nor was it appreciably affected by arelAlesion. Acid‐induced cells were more sensitive to alkali damage to both DNA and β‐galactosidase and to alkali inhibition of β‐galactosidase induction. Alkali sensitization induced at pH 5.5 may involve

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01108.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

P.F. LONG AND G.E. AMPHLETT. 1996. An increase in the abundance and diversity of non‐streptomycete actinomycetes isolated from soils was achieved after the number of streptomycetes was reduced by pre‐incubating the soil with streptomycete‐specific actinophage. This method is described as a super lytic actinophage s

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01109.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

M. SUNAIRI, N. IWABUCHI, K. MURAKAMI, F. WATANABE, Y. OGAWA, H. MUROOKA AND M. NAKAJIMA. 1996. Suitable conditions for the introduction of bacteriophage DNA into cells ofRhodococcus rhodochrousCF222 by electroporation were established, and penicillin G was found to enhance the transfection frequency. When conditions optimal for the parental strain were applied to its colony‐morphological mutants, different transfection frequencies were observed. Penicillin G enhanced the transfection frequency of smooth and mucoidal mutants but not of rough mutant

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01110.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

M. MÖLLER AND R. HARLING. 1996. A technique is described for the preparation of DNA suitable for use in RAPD analysis from pure, sterile resting spores ofPlasmodiophora brassicae. Using this technique, random 10‐base pair primers were applied toP. brassicaeDNA from three single spore isolates. The resulting profiles were compared with the race classification based on inoculation of the European Clubroot Differential (ECD) series of Brassica hosts. Out of 40 primers tested, 23 gave amplification products, three gave isolate‐specific profiles and one a profile which corresponded with the ECD race classification of the isolates. RAPD profiling can provide a faster means of race classification inP. brass

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01111.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

E. HUOT, C. BARRENA‐GONZALEZ AND H. PETITDEMANGE. 1996. A Comparative study of the inhibitory activity of nisin, the well‐known lantibiotic produced by certain strains ofLactococcus lactissubsp.lactis, and of the bacteriocin produced byL. lactissubsp.cremorisJ46, a strain previously isolated from fermented milk, was conducted. For both bacteriocins, the activity againstL. lactissubsp.cremorisdecreased with increasing pH. In addition, the bacteriocin preparations were more stable at 4 than at 20°C. The influence of the storage temperature was more crucial for nisin. Essentially the same activity was observed for bacteriocin J46 stored for 3 h at 4 or 20°C. More interesting was the observed stability of bacteriocin J46 at pH values between 5.8 and 6.8. For example, about 23% of nisin activity was lost at pH 6.4 whereas no loss of bacteriocin J46 activity was obs

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01112.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

J.‐A, McCARTHY AND A.P. DAMOGLOU. 1996. The radiation resistance of a selection of yeasts isolated from sausages was assessed in phosphate‐buffered saline and in sausage meat. The yeastsCandida zeylanoides, Debaryomyces hanseniiandTrichosporon cutaneumexhibited sigmoidal survival curves in both substrates whilst the more sensitiveSporobolomyces roseusexhibited an exponential survival curve in buffer but a sigmoidal curve in meat. IrradiatingC. zeylanoides, D. hanseniiandT. cutaneumin sausage meat changed the shape of their survival curves to significantly alter the calculated parametersDs(the dose in kGy that must be achieved before reduction in numbers occurs) andD10sig(the dose in kGy required after the shoulder to achieve a 1 log cycle reduction in numbers). TheDsvalues were reduced while higherD10sigvalues were obtained demonstrating that the sausage meat contributed a protective effect to these yeasts at higher irradiation doses. For the yeastS. roseus, similar numbers of survivors were recovered from both substrates at initial low irradiation doses (0–0.5 kGy) with the protective effect being demonstrated again at higher doses (>2 kGy). These findings should be considered when defining a commercial process to reduce the numbers of yeasts in these pro

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01113.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY