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doi: 10.1111/j.1365-2672.1989.tb02518.xpmid: N/A
The influence of species of Acetobacter and Gluconobacter upon growth of the wine yeasts Saccharomyces cerevisiae, Kloeckera apiculata and Candida stellata was examined during mixed culture in grape juice. Acetobacter pasteurianus, A. aceti and Gluconobacter oxydans grew in conjunction with yeasts during juice fermentation. As determined by viable counts, yeast growth was only slightly impaired by the presence of bacteria. However, as judged by the concentrations of glucose, fructose, ethanol, glycerol, acetaldehyde, ethyl acetate, iso‐amyl alcohol and organic acids in the fermented juice, acetic acid bacteria significantly influenced the alcoholic fermentation by yeasts.
doi: 10.1111/j.1365-2672.1989.tb02519.xpmid: 2592289
An empirical and generalized model is presented, based on a modified Arrhenius equation, for predicting the combined effect of temperature and water activity on the growth rate of bacteria. When it was applied to seven separate sets of wide ranging published results, spanning some 50 years and including a spore‐former and a silage micro‐organism, predictions explained between 92.9 and 99.0% of the variation in the results with an overall mean of 96.6%. Advantages over existing models are that it is relatively easy to fit to data using least squares regression and requires only five coefficients. These, together with its simplicity and demonstrated wide application, will facilitate its practical use.
doi: 10.1111/j.1365-2672.1989.tb02520.xpmid: N/A
Total plasmid DNA was successfully isolated from 46 of 55 strains of Pseudomonas syringae. Electrophoretic separation after digestion with restriction endonuclease EcoRI gave reproducible banding patterns. Cluster analysis of banding data grouped all strains of pathovar (pv.) pisi separately from pv. glycinea, pv. phaseolicola and pv. syringae. Pathovars glycinea and phaseolicola were more similar to each other than to pv. pisi. A relationship between fragment banding patterns and race structure within pv. pisi was observed.
Bhaduri, Saswata; Bandyopadhyay, S.; Bose, S. K.
doi: 10.1111/j.1365-2672.1989.tb02521.xpmid: 2512275
The sporulation of Bacillus subtilis B34 was repressed by 24 h if glutamine or ammonium chloride but not glutamate was added at late log phase (70 h) when glucose and glutamate were nearly exhausted. Glutamine‐resistant mutants were isolated by selective heat treatment during the delay period induced by glutamine. Glutamine‐resistant mutants showed cross resistance not only against ammonium chloride but also against glucose just as glucose‐resistant mutants showed resistance against nitrogenous catabolites.
doi: 10.1111/j.1365-2672.1989.tb02522.xpmid: N/A
A total of 302 strains of Bacillus thuringiensis flagellar (H) serotype 3, collected from sericultural environments and soils of the three main islands (Honshu, Shikoku and Kyushu) of Japan, were examined for their H antigenic subserotypes. Of these strains, 259 (85.8%) were identified as the H subserotype 3a : 3c (subsp. alesti), 16 (5.3%) were referable to the subserotype 3a : 3b : 3c (subsp. kurstaki), 26 (8.6%) belonged to the subserotype 3a : 3d : 3e (subsp. fukuokaensis) and one strain (0.3%) was the subserotype 3a : 3d (subsp. sumiyoshiensis). The subserotypes 3a : 3c and 3a : 3b : 3c were present in sericultural environments only; the former was distributed in Honshu and Shikoku Islands but not in Kyushu Island, and the latter was distributed in Honshu and Kyushu Islands but not in Shikoku Island. The subserotype 3a : 3d : 3e, mainly found in soils but occasionally in sericultural environments, was distributed in the three main islands. It also appeared that the subserotype 3a : 3d : 3e, a recently described subserotype, was distributed in Japan more widely than the globally disseminated subserotype 3a : 3b : 3c. The results clearly showed geographical and ecological differences in the distribution of subserotypes.
Jassim, S.; Salt, W.G.; Stretton, R.J.
doi: 10.1111/j.1365-2672.1989.tb02523.xpmid: 2592290
Staphylococcus aureus (five strains) and Staph. epidermidis (one strain) have been evaluated for comparative growth and haemolysin titre in both brain heart infusion (BHI) and in developed, nutritionally adequate, chemically defined media (CDMs) varying only in amino acid composition. The ability to show a particular haemolytic profile was strain‐dependent and the haemolytic titre (HU50/ml) was both strain‐ and medium‐dependent. Highest titres of both alpha and beta type haemolysins were obtained in BHI. Maximum titres were in general detected in the late exponential phase in both CDMs and BHI. Titres declined during the stationary phase in CDMs. Staphylococcus epidermidis produced a delta‐type haemolysis profile on BHI‐based blood agars, but only rabbit blood was sensitive in agars based on a developed, chemically defined medium (CDM/A; 13 amino acids) in which all six staphylococci grew. The addition of yeast extract to CDM/A increased alpha haemolysin titre, but suppressed beta haemolysin formation; beta haemolysin was, however, detected in yeast extract/phosphate‐buffered saline. Strain Wood 46 degraded haemoglobin, but only in (initially) whole blood; red blood cell‐free haemoglobin‐rich plates (BHI) were unaffected during growth. A novel haemolytic profile is described for Staph. aureus NCTC 8532 growing on blood agars based on CDM/A and may relate to the production of methaemoglobin during haemolysis.
Macfarlane, G.T.; Cummings, J.H.; Macfarlane, S.; Gibson, G.R.
doi: 10.1111/j.1365-2672.1989.tb02524.xpmid: N/A
Hydrolytic enzymes were measured in gut contents from four sudden death victims. Pancreatic amylase and total protease activities decreased distally from the small bowel to the sigmoid/rectum region of the large intestine, showing that considerable breakdown or inactivation of the enzymes occurred during gut transit. To determine whether pancreatic enzymes were substrates for the gut microflora, mixed populations of bacteria were grown in a 3‐stage continuous culture system on a medium that contained pancreatic extract as the sole nitrogen source. The multichamber system (MCS) was designed to reproduce in vitro, the low pH, high nutrient, fast growth conditions of the caecum and right colon and the neutral pH, low nutrient, slow growth conditions of the left colon. Results showed that pancreatic amylase was resistant to breakdown by intestinal bacteria compared with the peptide hydrolases in pancreatic secretions. Leucine aminopeptidase, trypsin and to a lesser degree, chymotrypsin, were easily degraded by gut bacteria, but pancreatic elastase was comparatively resistant to breakdown. Protein degradation in the MCS, as determined by enzyme activities, protein concentration and ammonia and phenol production, increased concomitantly with system retention time over the range 24–69 h. These results suggest that intestinal bacteria play an important role in the breakdown of hydrolytic enzymes secreted by the pancreas and that this process and protein fermentation in general, is likely to occur maximally in individuals with extended colonic retention times.
Milliere, J.B.; Mathot, Anne‐Gabrielle; Schmitt, P.; Divies, C.
doi: 10.1111/j.1365-2672.1989.tb02525.xpmid: N/A
A numerical taxonomic analysis was performed on 81 strains belonging to the Gram‐positive, heterofermentative genus Leuconostoc. These came from different raw milk samples used for cheese manufacture, milk starters, wine and culture collections. Strains were examined for 197 phenotypic characters. On the basis of carbohydrate fermentation, citrate use and dextran production, all the strains were recovered in three clusters at a similarity level of 38% Sj. One cluster was composed entirely of the 11 L. mesenteroides subsp. cremoris strains, characterized by a poor carbohydrate fermentation capacity. The second cluster was very heterogeneous: it contained 60 strains that fermented many carbohydrates, but it was not possible to discriminate between the named species. The third cluster consisted of the 10 L. oenos strains. The addition of antibiotic resistance responses and enzymatic profiles (arylamidase, esterase and hydrolase activities) yielded no significant difference between the strains and did not allow a better discrimination. Only the attribution of a taxonomic weight to some carbohydrate fermentation tests and the use of genetic analyses can resolve the strain identification.
doi: 10.1111/j.1365-2672.1989.tb02526.xpmid: 2592291
Two methods of determining the heat resistance of bacteria, a glass cup and a test tube method, were compared with a method using capillary tubes. Three strains of Yersinia enterocolitica, one of Campylobacter jejuni and two of C. coli were tested in physiological saline. The differences between the results obtained by the glass cup method and the reference method were not statistically significant for five strains and were small also for the other, a Yersinia strain. D values obtained by the glass cup method at 58, 60 and 62°C were 1.4–1.8, 0.40–0.51 and 0.15–0.19 min (z values 4.00–4.52°C) for the Yersinia strains, and 0.42, 0.13 and 0.07 min (z value 5.07°C) for one C. coli strain. For the other Campylobacter strains, D values of 0.71–0.78, 0.24–0.28 and 0.12–0.14 min (z values 4.94 and 5.60°C) were recorded at 56, 58 and 60°C. D values obtained at 60°C by the test tube method were 2.7–5.0 min and were considered to be unrealistic.
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