摘要:

Summary.The effect of sucrose or mixtures of sucrose and glucose, in the heating menstruum, on the heat resistance of 4 organisms,Salmonella senftenberg, Salm. typhimurium, Saccharomyces rouxiiandTorulopsis globosa, was investigated and the results have been expressed in terms ofDandzvalues against water activity (aw). The effect on the cell of sucrose solutions, both with and without heat, was also investigated. Measurements of cell volume obtained from phase contrast micrographs and of O.D. showed that as the sucrose concentration increased, the volume of the cell decreased. The increased heat resistance exhibited by cells in sucrose solutions of lowawis thought to be the result of a dehydration of the cell together with a reduction in the pore size of the cell wall.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04118.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.The aerobic flora of the skin of 56 Atlantic salmon from coastal, estuarine and river waters was analysed quantitatively; 50 skin and 33 gill samples were analysed qualitatively. The water at each sampling station was also analysed. The principal genera on the skin and gills wereMoraxella, Flavobacterium, CytophagaandPseudomonas; members ofAcinetobacter, Bacillus, Aeromonas, Vibrio, the Entrobacteriaceae, Micro‐coccaceae and some coryneforms were also present. The gill flora was similar to that of the skin, which reflected that of the environmen

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04119.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.Polyethylene glycol 400 monolaurate (PGM), a nonionic surfactant, affected the solubility of trichlorocarbanilide (TCC), the amount solubilized being directly proportional to the concentration of PGM in the system. The bacteriostatic activity of TCC againstStaphylococcus aureuswas affected by high but not low concentrations of PGM; proportions of PGM to the germicide of up to 10: 1 did not interfere with the minimum inhibitory concentration (MIC) of TCC (0·08 μg/ml). The bactericidal activity againstStaph. aureusof systems consisting of TCC and different proportions of PGM with and without 0·5% of NaCl was much higher than that of saturated aqueous solutions of TCC alone. However, TCC solutions containing NaCl and PGM were more bactericidal than corresponding systems without NaCl; the death rates in TCC‐PGM‐NaCl systems were 2–4 times that in TCC‐PGM systems. The marked increase in the death rate was obtained with systems containing 2

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04120.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.The total anaerobic count on contents of the gastro‐intestinal tract of 7 piglets, fed on a milk powder diet, was determined with the ringed plates technique of Van der Heyde and the roll tube method of Hungate. Simultaneously, the oxidation‐reduction potential (Eh) was measured in the different segments. For caecal and large intestinal contents, higher counts were obtained with the roll tube method. Nevertheless, the proportional composition of the dominant flora was identical for both methods. Marked differences between theEhof the different gastro‐intestinal segments were obs

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04121.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.Death of euryhaline fish in an aquarium was caused by iodine liberated in seawater by a marine bacterium. The isolation of a pure culture ofPseudomonas iodooxidanssp. nov., highly resistant to iodine, led to the elucidation of the mechanism involved. Iodides were oxidized to free iodine by an extracellular peroxidase system and hydrogen peroxide was generated by the bacteria. The importance of this finding is discussed in the light of current knowledge of the iodine cycle in nature.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04122.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.Glutaraldehyde was readily taken up byEscherichia colicells with an increase in solutions buffered to pH 7·9; it was paralleled by a corresponding increase in bactericidal activity. Attempts to desorb glutaraldehyde from the cells indicated that the drug molecules were firmly bound. Inhibition of synthesis of macromolecules was demonstrated. Cell walls ofE. coliexhibited a much reduced rate of hydrolysis following treatment with glutaraldehyde

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04123.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.An arbitrary parameter ‘rejection time’, i.e. the time required for a fungal inoculum to form a 2 mm diam. colony, was used to express the shelf life of jam after unsealing and exposure of the contents to airborne contamination. Individual and combined effects of water activity (aw), pH value and temperature on rejection time of low sugar jam were estimated from the radial growth on agar of colonies of 9 fungi. The decreases inaw(0·94–0·90) and temperature (25–15°) practicable for low sugar jam were more effective in increasing rejection time than the feasible decrease in pH value (3·7–2·9). The interaction betweenawand temperature was significant. The effect of the changes inaw, temperature and pH on rejection time was broadly similar for media adjusted by either sucrose or glycerol. At a givenaw, moulds were slightly more tolerant of glycerol than sucrose but yeasts, except for the osmophileSaccharomyces rouxii, were markedly more tolerant of glycero

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04124.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.In initial surveys of Indonesian waters and marine animals,Clostridium botulinum, predominantly of types A and C, was detected in 10% of all enrichment cultures tested.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04125.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.Two methods of viewing surfaces by incident fluorescence microscopy are described for application in microbiological studies associated with food manufacture, agricultural research and dermatological investigations.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04126.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Summary.A study of viable aerobic heterotrophic bacteria in the open water of Blelham Tarn and in 2 large experimental tubes introduced into the tarn, demonstrated certain differences between the populations during the period of thermal stratification. Whereas a relatively stable mixture of several species was found in the tarn, the populations of the tubes were often dominated by cycles of single species, including those from genera tentatively identified asAcinetobacter, Flavobacteriumgroup,Moraxella, coryneform group andAeromonas.It was not possible to be certain which factors had caused this change in the species composition, but it was noted that some nutrients, especially phosphate‐phosphorus and iron, became depleted in the tubes. The other major difference between the tarn and the experimental tubes was that complete deoxygenation of the hypolimnion was found only in the former. The bacterial populations of the tarn and the tubes were similar after overturn and during all periods when conditions were isotherma

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1973.tb04127.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY