ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01384.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The effects of different gaseous atmospheres were determined on the maximum specific growth rate (μmax) and end‐product formation byBrochothrix thermosphactaATCC 11509T,Lactobacillus viridescensSMRICC 174 andLactobacillussp. SMRICC 173 (homofermentative). The highest μmax‐values forLact. viridescens(0.47/h) andBroc. thermosphacta(0.49/h) were obtained in air. Under anaerobic conditions μmaxwas reduced, an atmosphere containing CO2alone giving the greatest reduction.Lactobacillussp. 173 did not grow in air or N2. Aerobic growth was obtained by adding peroxidase while anaerobic growth occurred in the presence of 5–20% CO2. Carbon dioxide alone reduced the growth rate. All test organisms produced mainly lactic acid anaerobically.Lactobacillus viridescensalso produced ethanol whileBroc. thermosphactaproduced small amounts of ethanol and formic acid. With O2present, the number of end‐products increased for all organisms.Lactobacillussp. 173 produced small amounts of acetic acid and acetoin together with lactic acid. Oxygen induced acetic acid production inLact. viridescensandBroc. thermosphacta. Aerobically,Broc. thermosphactaalso produced a large amount of acetoin and smaller amounts of 2,3‐butanediol,iso‐valeric acid andiso‐butyric acid. The production of lactic acid byBroc. thermosphactawas completely prevented under strictly aerobic conditions. All test organisms consumed O2during aerobic growth. Hydrogen peroxide was produced byLact. viridescensandLact

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01385.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

An ∝aL‐amylase activity has been observed in lactic acid bacteria occurring initially in fermented fish silage. The organisms belong to the genusLeuconostoc. The main fraction of the amylolytic enzyme produced by one of the isolated bacteria is cell‐bound and is released into the medium at a late stage of growth. Treating cells with ultrasound or Triton X‐100 increases enzyme activity in the culture filtrate. The pH range for enzyme activity is 5.0–7.0, with an optimum at pH 6.0. The enzyme is extremely labile at pH 8.0 and is inactivated at temperatures above 50°C at pH 5.8. Two enzyme fractions were found by isoelectric focusing, the main one at pH 5.00 and another at pH 4.5. Chromatography on DEAE cellulose gave two ac

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01386.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The presence of NaCl in the heating medium provided some protection from lethal heat damage for cells of aStreptococcus faeciumstrain isolated from luncheon meat whereas the presence of NaNO2either alone or in addition to NaCl, had no significant effect on cell survival. Subsequent recovery and growth of heat‐damaged cells was retarded by the presence of NaCl. When NaNO2was present in addition to NaCl the inhibitory effect of the latter was reduced. These principal components of the luncheon‐meat‐cure are apparently opposed in their activities on post‐heating recovery and growth ofStrep. faecium. Product stability, i.e. duration of the lag before growth occurs, is directly related to the severity of the heat treatment and to the concentration of NaCl in the product. Therefore the resistance of pasteurized chub‐packed luncheon meat to streptococcal spoilage during storage at temperatures conducive to microbial growth results from a prolonged heat‐induced salt‐maintained pre‐growth adjustment phase rather than to any inherent inhibitory property of the luncheon meat to the growth of non‐heat‐damaged

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01387.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

An analysis of the effect of growth conditions on the growth (O.D. values) of fiveVibrio anguillarumstrains showed that the optima were as follows: pH 7, temperature 25°C, NaCl concentration 2%, and O.D. estimates increased with the incubation time. The independent parameters, as well as their interactions significantly influenced the growth ofVibrio anguillarum(P0<0001). Only the strain‐salinity interaction was not always statistically significant. A restriction of the parameters to a level relevant for Danish marine recipients showed that pH and NaCl concentration (salinity) might be of minor importance while the temperature was always of high significance. The possible impact of these observations on local conditions is discuss

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01388.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Vibriospp. predominated in the culturable bacterial community of surface waters of the Puerto Rico Trench at the site of disposal for nearly ten years of pharmaceutical wastes. In this area and surrounding waters as far as 1000 km north of the dumpsite and south into the Caribbean Sea,Vibriospp. comprised up to 100% of the culturable bacteria, withAcinetobacterspp. being the second most prevalent group.Pseudomonasspp., reported to be common in these waters a decade earlier, were virtually absent from all samples examined during a three year study involving 9 cruises.Staphylococcusspp. were also found in water samples collected within the dumpsite. Using cultures isolated from surface water samples collected at the dumpsite, laboratory experiments confirmed that pharmaceutical waste can enrich forVibriospp., in preference toPseudomonasspp., with growth of the strains proportional to the amount of waste added.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01389.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Proteolytic thermophilic bacterial cultures (171 strains) were isolated from different milk and milk products. After screening these isolates for protease production in a liquid medium, fifty that exhibited enzyme activity in excess of 100 units/ml were selected and identified. Twenty‐nine wereBacillus stearothermophilus(constituting 58% of the total), twelve wereB. coagulans, five wereB. circulansand four wereB. licheniformis. Skim milk powder contributed the maximum number ofB. stearothermophilus(64.7%) followed by raw milk (63.2%) and pasteurized milk (44.4%). When the culture supernatant liquids from the selected isolates were given heat treatment, five cultures retained 100% protease activity at 65°C for 30 min. Protease ofB. stearothermophilusRM‐67 had the maximum heat resistance because it retained 87.5% of its activity at 70°C for 3

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01390.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Group B streptococci (Streptococcus agalactiae) from humans and animals were compared for cultural, biochemical, serological and bacteriocin sensitivity properties. Each isolate possessed the group B carbohydrate antigen, hydrolysed hippurate, and was CAMP test positive. Most human isolates were characterized as bacitracin resistant, pigment producing, haemolytic, and salicin but not lactose utilizing. In contrast bovine isolates were usually bacitracin sensitive, non‐pigment producing, non‐haemolytic, salicin and lactose utilizing. Isolates from other animals behaved similarly to those from humans. Whereas human isolates belonged to a variety of serotypes and were uniformly sensitive to bacteriocins, bovine isolates showed varying sensitivity to bacteriocins and most belonged to serotype II or were non‐typable. We believe these results support the belief thatStrep. agalactiaefrom humans and cattle are separate populations sharing the same group B carbohydrate an

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01391.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A computer program and accompanying data matrix have been prepared for bacteria of medical interest, to assist the assignment of an unidentified bacterium to the most likely genus. The results on a set of relatively simple tests are entered. The program prints the more likely genera, followed by a list of diagnostic tables in Cowan&Steel (1974) and Buchanan&Gibbons (1974). Where available, identification matrices for further computer‐assisted study, are presented. This program may be of particular help in laboratories where a wide range of bacteria have to be identifie

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01392.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Pseudomonas tolaasiiandPs. gingericultures isolated from naturally diseased mushrooms and cultures obtained from other workers were all observed to contain both smooth and rough colony forms. The smooth forms produced mucoid, non‐fluorescent, glistening opaque colonies with entire margins. The rough forms produced non‐mucoid, fluorescent, dull, translucent greenish‐yellow colonies with irregular margins. Smooth forms were observed to produce a toxin and were pathogenic to mushrooms, whereas rough forms did not produce toxin and were non‐pathogenic. Isolates ofPs. tolaasiiwere distinguishable fromPs. gingeriby various biochemical tests. In general, however, biochemical differences between the rough and smooth forms of each species could not be detected. Rough forms ofPs. tolaasiiandPs. gingeriremained stable in culture but smooth forms were unstable, tending to convert to rough forms at a very hi

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1984.tb01393.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY