ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:Sterilized raw sewage sludge enriched with sulphate and inoculated with pure strains ofDesulphovibrio desulphuricansproduced negligible sulphide. Unsterilized sludge supplemented with 7% (w/v) CaSO4.2H2O and inoculated with crude cultures of sulphate‐reducing bacteria obtained from sewage yielded 1·0% S2‐(wt S2‐produced as H2S/vol. of raw sludge) in 6 months at 30°. By repeated subculture more active cultures developed which produced 1% S2‐in 7 days and 1·2–1·9% in 28 days. Digested sludge yielded only 0·1% S2‐. In semicontinuous fermentations at 30°, raw sludge without added sulphate produced 20 times its own volume of gas containing 70% CH4and 30% CO2. When 5% CaSO4.2H2O and an active crude culture of sulphate reducers were added, gas production decreased steadily to zero. There were no differences in pH, temperature and redox potential in sludges producing methane or sulphide. The chief cause of inhibition appeared to be the action of sulphide: 0·02% soluble sulphide (S2‐) totally inhibited methane formation; 0·01% S2‐initially decreased gas production by one‐quarter but there was a slow recovery to normal, suggesting acclimatization of the methane‐producing organisms to sulphide.Linked fermentations, in which gas from a methane fermentation swept H2S from a sulphide fermentation, gave a final gas mixture of about 60% CH4, 30% CO2and 5–10% H2S. The yield of sulphide dep

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00036.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:The determination of the coli‐aerogenes content of raw milk by smearing 0·1 or 0·2 ml of suitable dilutions on dried Levine's eosin methylene blue agar plates and incubating at 37° or 30°, was found too unselective as a routine technique. Only about two‐thirds of the colonies showing the characteristic appearance of coli‐aerogenes bacteria were confirmed as such by the formation of acid and gas in MacConkey's broth. Appreciable proportions of the numerous rose coloured colonies and of the very small dark colonies with metallic sheen, which are not considered to be coliaerogenes bacteria, formed acid and gas in MacConke

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00037.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:The main obstacles to the general acceptance of the Clegg&Sherwood (1947) method for the examination of molluscan shellfish are thought to be the difficulties of preparing the medium and of rolling the tubes satisfactorily. The use of Astell or McCartney bottles, or sealed plates, in place of the conventional 6x1 in. test tubes, is described.The following simplified MacConkey medium is recommended in place of that of Clegg&Sherwood (all quantities % w/v): agar, 3·5; peptone, 1·5; lactose, 1·0; NaCl, 0·5; bile salt (Difco No. 3), 0·15 or Oxoid, qs.; neutral red, 0·003; distilled water to 100 ml, pH 7·2–7·4. With 5 ml of this medium inocula of 2 ml may be used. Oxoid MacConkey agar No. 3 (CM. 115a) is equally suitable.A brief account is given of the use of this method and examples of the better performance of the new medium for the examination of molluscan

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00038.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:A comparison of the 15‐tube liquid dilution method for estimating the most probable number ofEscherichia coliI in sea water with a direct roll‐bottle count at 44° using a modified MacConkey's agar revealed no significant differences.The advantages of the roll‐bottle method include greater accuracy, economy of time and materials, speed with which results are obtained and greater range of pollution that may be estimated without diluting the

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00039.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:Forty‐six strains ofAcetobacter, representing twenty species, have been compared on the basis of their respective abilities to proliferate in two defined inorganic media, in which either glucose or ethanol was the sole source of carbon and energy. Twenty‐three strains, representing eleven species, grew in either inorganic medium when glucose was present and nine of these strains, representing five species, could grow also in either inorganic medium when ethanol was present. The remaining twenty‐three strains, representing eleven species, failed to grow in either medium with either glucose or ethanol. Three organisms grew better with ethanol than with glucose and three were inhibited by ethanol in the presence of gl

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00040.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:The presence of a caecal microflora has been demonstrated in newly hatched chicks that had not received food or water. The flora was composed mainly of clostridia, sometimes withEscherichia coli.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00041.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:Tests carried out on coagulase positive staphylococci isolated from bulk milk supplies showed a nearly perfect relationship between α‐lysin production and pigment production at 42°. Ninety‐nine per cent of the organisms were classed as pathogenic, while 75% were probably responsible for sub‐clinical conditions in th

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00042.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:Milk, before and after commercial sterilization, supplied by ten different sterilizing depôts, was examined over a period of 18 months to determine the aerobic mesophilic spore content. The numbers present in raw bulk tanker milk exhibited a seasonal variation, the counts being higher in winter than in summer. This was not found in sterilized milk. Spore counts in raw milk ranged from 0—700/100 ml and in sterilized milk, with one exception, from 0—1·1/100 ml.During the last 12 months of the experiment the types of aerobic mesophilic spore forming organisms causing spoilage were isolated and identified, using a simplified method of identification. Eight different species were isolated from raw milk and seven from sterilized milk. The incidence of the different types in raw milk was:B. licheniformis, 62%;B. brevis, 15%;B. subtilis, 7%; others 9% and unidentified, 7%. In sterilized milk this was:B. subtilis, 44%;B. licheniformis, 26%; others, 17% and unidentified, 13%. There was no apparent seasonal variation in

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00043.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY:A medium has been devised for the culture of bacteria from freshHevealatex, ammoniated field latex and ammoniated latex concentrate. It is a modification of Kligler's iron agar, and can be used as a counting medium.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1956.tb00044.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY