摘要:

Summary.The growth ofStaphylococcus aureus111 was inhibited by aliphatic alcohols. The extent of inhibition by primaryn‐alcohols increased with the elongation of the chain. Secondary alcohols were less inhibitory than the corresponding primary alcohols. The inhibitory effect was influenced by the distance of the hydroxyl group from the end of the carbon chain. When the alcohols were added to the medium in sub‐inhibitory amount, enzyme synthesis by the bacteria was decreased, but there was no demonstrable inhibition of enzyme already for

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00409.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.Two methods for the rapid detection and estimation of numbers of faecal coliforms andEscherichia colitype I in oysters have been developed. That for faecal coliforms involves incubation of tubes of MacConkey broth for 2 h at 37° and then for 22–24 h at 44°. The second method, a modification of MacKenzie, Taylor&Gilbert's (1948) specific method forE. colitype I, makes use of the same system of incubation, but requires the inoculation of tubes of peptone water as well as MacConkey broth, the former tubes being used for subsequent testing for indole formation. Both methods take only 24–26 h and are as sensitive and accurate as the Most Probable Number methods which are in common use and which take upwards of 72–96 h to c

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00410.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.The ability of 111 isolates of 33 species ofBacillusto hydrolyze hippurate into benzoic acid and glycine was tested. All, other than the strains classified asB. badius, B. cereusvar.mycoides, B. cereusvar.thuringiensis, B. macquariensis, B. medusa, B. pacificus, B. psychrosaccharolyticusand someB. maceransandB. polymyxastrains, were positive by thin layer chromatography (TLC). Of the 4 methods compared (hippurate agar, the sulphuric acid method, precipitation with ferric chloride and TLC), only the TLC procedure allowed a rapid and definite detection of the hydrolytic product, benzoic acid. The use of hippurate hydrolase as an additional diagnostic aid in the differentiation of aerobic spore‐forming bacilli is discussed. Other characters were used to compare some recently describedBacillusspp. The combinationB. cereussubsp.medusan. subsp. is propose

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00411.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.The heat resistance at 65° of 3 strains of salmonellae in solutions of sugars or polyols was enhanced as the concentration of the solutes increased. There was no linear relationship between heat resistance and water activity (aw), but for all solutes except glycerol there was a linear relationship between logD65and concentration (% w/w) of solute. Comparison ofD65at a particularawor percentage (w/w) solute concentration showed that the value decreased in the order: sucrose>glucose>sorbitol>fructose>glycerol. In glycerol,D65values were always very much lower than in any other solute. With sucrose–glycerol or sucrose–glucose mixtures, heat resistance depended both on the total concentration (% w/w) of solutes present and also on theawof the solu

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00412.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.The recovery ofPseudomonas aeruginosa, Escherichia coli, andStreptococcus faecalisfrom aqueous suspending media has been studied with a rich plating medium (trypticase‐soy agar) and selective media. Tap water was highly toxic to all strains investigated. Recovery ofPs. aeruginosawas most successful when phosphate buffer was the diluent. Phosphate buffer did not improve the recovery ofE. coli. Streptococcus faecalisremained viable when suspended in double distilled water, deionized distilled water or phosphate buffer. Following a lag period all strains grew in 0.1% peptone water or stream water. Injury preventing recovery of viable cells on selective media occurred during suspension in all aqueous media tested, including those which supported growth. These observations suggest difficulties inherent in the interpretation of bacteriological results obtained during surveys of water sources and a need to reduce the selectivity of recovery media against injured cell

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00413.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.A culture ofStaphylococcus aureusin trypticase‐soy broth incubated at 5° became increasingly sensitive to mannitol‐salt agar. The sensitivity was affected by the pH value of the suspending medium. On transfer to 37° the culture rapidly regained the ability to form colonies on the selective m

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00414.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.The pink pigment ofPseudomonas extorquenswas identified tentatively as an oxo‐carotenoid similar to rhodoxanthin. The production of the pigment increased at the end of the logarithmic phase of growth ofPs. extorquensin batch cultures. It was produced during growth on a wide variety of carbon and nitrogen sources, with the exception of ethanol, but not in the presence of diphenylamine, an observation which was consistent with the identification of the pigment as a carotenoid. The organism was grown in continuous culture under conditions of oxygen and magnesium limitation which might be expected to restrict the oxidation of γ‐carotenes to pink pigments. However, such limitations caused an increase in pigmentation over that of methanol‐limited cultures. Non‐pink mutants ofPs. extorquens, obtained after the use of the mutagen, ethyl methyl sulphonate, did not have growth‐rates lower than those of the parent strain. The pigment would seem to have no central metabolic role in actively growing cells but carbon is diverted to pigment production when growth is restricted by other than carbon

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00415.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.Activated sludge receiving ammonium thiocyanate (500 mg/l) was able to nitrify. The rate of ammonia oxidation was decreased when>3 mg/l of phenol (or cresols) was added to the sludge, and at 10 mg/l was inhibited completely. Concentrations of up to 100 mg/l of phenols did not affect nitrite oxidation. The 2‐ and 4‐methyl pyridine derivatives inhibited both ammonia and nitrite oxidat

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00416.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.Low concentrations (0.025–0.125%) of glutaraldehyde inhibited or prevented colony formation byEscherichia coli, Bacillus subtilisandB. pumilisin agar, and inhibited germination of spores of theBacillusspp. in L‐alanine plus D‐glucose. Higher concentrations (2%) of glutaraldehyde at pH 8.5 were sporicidal. Pre‐treatment of spores with glutaraldehyde lessened release of dipicolinic acid when the spores were subsequently heated at 100°, but not at 121°. Spores treated with glutaraldehyde and then with 0.5 M thioglycollic acid in 6 M urea at 70° were less sensitive to lysis by hydrogen peroxide than spores which had not been exposed to glutaraldehyde. Glutaraldehyde was less effective in preventing peroxide induced lysis if added to spores which had been previously exposed to thioglycollic acid plus urea at 70°. The mechanism of the sporicidal activity of glutaraldehyde is discussed in relation to the

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00417.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.A rapid reduction, after manufacture, in numbers ofRhizobium trifoliiin commercial legume inoculants was observed in 1971 and explained by the presence of high concentrations of sodium chloride in the peat used as carrier material. A strain ofR. trifoliigrowing in broth proved to be more sensitive to sodium ions than did 2 strains ofR. melilotibut was more tolerant of up to 0.3% of chloride. The effect of salt differed somewhat according to the source of peat used as carrier, but peat containing °0.2% of chloride (expressed as a % of dry peat) may cause considerable loss of viability of rhizobia

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1974.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY