摘要:

M.H.P. FUNGARO, M.L.C. VIEIRA, A.A. PIZZIRANI‐KLEINER AND J.L. DE AZEVEDO. 1996. Random amplified polymorphic DNA (RAPD) was used in order to analyse the relationships among 13 isolates ofMetarhizium anisopliaevar.anisopliae. Six of them were isolated fromDeois flavopicta(Stal) (Hemiptera—Homoptera: Cercopidae) in different regions of Brazil. The other seven were isolated from soil in Paraná State in Southern Brazil. The isolates were grouped by cluster analysis using Dice similarity index. The results show that isolates ofM. anisopliaevar.anisopliaeare extremely diverse (47% similarity) but those isolated fromD. flavopictapresent only a moderate degree of variation (82% similarity) when compared with the wide diversity (31% similarity) found in the group isolated from soil. These results suggest thatM. anisopliaevar.anisopliaehas developed host specifi

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01186.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

D.E. GUILFOYLE AND I.N. HIRSHFIELD. 1996. The short‐chain organic acids (SCOAs), acetic and propionic acids, are used widely as food preservatives. The production of these two acids plus butyric acid in the colon by anaerobes serves as a mechanism for controlling the numbers of enterobacteria (which can be pathogens) in this organ. It has been found in this study that the acid tolerance of cells initially grown at near neutral pH (6.5) to a lethal pH of 3.5 is enhanced by their exposure to 0.1% propionate or butyrate. The data also indicate that the inducible arginine and lysine decarboxylases are important for the survival ofEscherichia coliexposed to a combination of mildly acidic pH (5.5) and 0.5% butyrate. This study suggests that the presence of SCOAs could trigger an adaptive survival response which may be important in the survival of food‐borne pathog

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01187.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

K.Y. JANG AND Y.D. HANG. 1996. The blue cheese mold,Penicillium roquefortiiNRRL 844, was found to produce a transfructosylating enzyme that exhibited optimal activity at 50°C in the pH range of 5.0–6.0. The enzyme rapidly catalysed the conversion of sucrose to a syrup containing nearly 60% fructo‐oligosaccharides of the total sugars pre

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01188.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

I. BALOGH AND A. MARÁZ. 1996.STAgenes are responsible for producing extracellular glucoamylase enzymes inSaccharomyces cerevisiaevar.diastaticus. These genes exist in three forms, which are located on three different chromosomes. The nucleotide sequences of theSTAgenes are highly homologous. A sporulation‐specific glucoamylase gene calledSGA1exists in everySaccharomyces cerevisiaestrain, this also having a partly homologous DNA sequence with theSTAgenes. In this studyS. cerevisiaevar.diastaticusand brewer's yeast strains were characterized by pulsed‐field gel electrophoresis. In many cases chromosome length polymorphism (CLP) was found. The chromosomes were hybridized with a DNA probe which was homologous withSTAgenes and theSGA1gene. Presence of theSGA1gene was detected in each strain used. Four brewing yeasts were found to have homologous sequences with theSTA3gene on chromosome XIV despite the fact that these strains were not able to produce extracellular glucoamylase en

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01189.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

M.Z.H. SABLI, P. SETLOW AND W.M. WAITES. 1996. α/β‐Type small acid‐soluble proteins (SASP) bind to spore DNA and protect it against ultraviolet light, heat, hydrogen peroxide and freeze drying, making the spores much more resistant than vegetative cells to these agents. Spores of a mutant ofBacillus subtilislacking the two major α/β‐type SASP were almost 30 000‐fold less resistant to hypochlorite than were wild‐type spores. After treatment with hypochlorite, surviving spores of the mutant, but not those of the wild type, showed higher levels of mutation, suggesting that SASP contribute to hypochlorite resistance by protect

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01190.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

J.L. THOMPSON AND M. HINTON. 1996. The size ofEscherichia coliandSalmonella enteritidisPT4 cells was measured using both transmission electron micrographs and image analysis. Incubation in the presence of formic and propionic acids resulted in larger cells, possibly as a result of DNA inhibition, with no apparent damage to the cell membranes. Bacteria incubated with propionic acid were more resistant to shrinkage after fixation, possibly as a result of altered phospholipid and fatty acid composition.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01191.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

P.‐C. LIU, K.‐K. LEE AND S.‐N. CHEN. 1996. The pathogenicity of sixVibrio harveyistrains in tiger prawn,Penaeus monodon, was studied, using both live bacteria and extracellular products (ECP). The organisms originally isolated from diseased penaeids were more virulent using both live bacteria and ECP (LD50, 4.87–8.65 times 104colony‐forming units (cfu) and 1.20–1.51 μg protein g‐1body weight) than the two reference strains originally isolated from either sea water (ATCC 25919; LD50, 3.18 times 106cfu and 2.70 μg protein g‐1body weight) or diseasedTalorchestiasp. (ATCC 14126, 0.418 times 106cfu and 2.34 μg protein g‐1body weight). Each strain was reisolated from the haemolymph and the hepatopancreas of moribund prawns following each bacterial challenge. Both the live bacteria and the ECPs of the penaeid isolates exhibited stronger proteolytic (caseinase), phospholipase and haemolytic activities than those of the reference strains. These results indicate that there are differences between penaeid and non‐penaeid isolates ofV. harveyiin pathogenicity and reveal that proteases, phospholipases, haemolysins or exotoxins might play leading roles in the pathogenicity ofV. harveyiin the tiger

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01192.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

M.E. FARÍAS, R.N. FARÍAS, A.P. DE RUIZ HOLGADO AND F. SESMA. 1996. Enterocin CRL 35, a bacteriocin produced byEnterococcus faeciumCRL 35 that inhibits food‐borne pathogens, was purified by precipitation with (NH4)2SO4, gel filtration, ion exchange and reverse phase chromatography. The partial N‐terminal amino acid sequence indicated a strong homology with other ‘pediocin‐like bacteriocins’ previousl

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01193.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

K. ARIHARA, S. OGIHARA, T. MUKAI, M. ITOH AND Y. KONDO. 1996. Fifteen of 353 environmental isolates of lactic acid bacteria consistently showed activity againstListeria monocytogenes, Streptococcus mutans, Actinomyces viscosus, and/orPropionibacterium acnes. Strain T140, isolated from the surface of Japanese pampas grass leaves and identified asLactobacillus salivariussubsp.salicinius, also had activity against severalLactobacillusspecies,Staphylococcus aureusandYersinia enterocolitica. Since the antagonistic factor(s) produced by T140 was sensitive to a proteolytic enzyme, it was concluded that a bacteriocin (named salivacin 140) was involved in the inhibition activity. Strain T140 required a high initial pH (7.5–8.5) in agar plates for bacteriocin productio

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01194.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

T.B. HANSEN AND S. KNØCHEL. 1996. Heating at slowly rising temperatures is suspected to enhance thermotolerance inListeria monocytogenesand, since anaerobic environments have been shown to facilitate resuscitation of heat‐injured cells of this micro‐organism, concern may arise about the possibility ofL. monocytogenessurviving in minimally preserved products. The effect of rapid (>10°C min‐1) and slow (0.3 and 0.6°C min‐1) heating on survival ofL. monocytogenesin sous vide cooked beef was therefore examined at mild processing temperatures of 56, 60 and 64°C. No statistically significant difference (P= 0.70) was observed between the tested heating regimes. Since the average pH of beef was low (5.6), and little or no effect was observed, a pH‐dependency of heat shock‐induced thermotolerance inL. monocytogenesis suggested to account

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1996.tb01195.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY