bluuebunny/crossref_metadata_2025 huggingface dataset:
Serological Activity of ‘Bacteroides fragilis’ Culture Supernatants
Authors: MEISEL‐MIKOŁAJCZYK FELICJA , ROKOSZ ALICJA , GRZELAK‐PUCZYŃSKA IRENA
Published: March 2008

Culture supernatants of 17 strains of the ‘Bacteroides fragilis’ group were treated with four volumes of acetone. The precipitates, after dialysis and lyophilization, were used as antigens in the double diffusion test with antisera against serotype strains of ‘B. fragilis’. In the culture supernatant of one strain we did not demonstrate the presence of serologically active substances. Sixteen preparations reacted in immunodiffusion with antiserum against ‘B. ovatus’ serotype B. Ten preparations reacted with antiserum B only and six preparations gave, additionally, precipitation lines with other serotype antisera (A, E2).
An Electrophoretic Analysis of Variation in the Glucose‐6‐Phosphate Dehydrogenase and Malate Dehydrogenase of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio fluvialis
Authors: MOMEN H. , SALLES C. A.
Published: March 2008

A total of 59 isolates of Vibrio cholerae, V. parahaemolyticus and V. fluvialis were studied using the techniques of enzyme electrophoresis. The enzymes used were malate dehydrogenase (E.C.I. 1.1.37) and glucose‐6‐phospate dehydrogenase (E.C.I. 1.1.49). The results in general confirmed classical methods of vibrio taxonomy. The three species could be separated from each other and identified by their enzyme variant types.

The term zymovar, a group of strains having similar enzyme variants, is introduced. In the V. cholerae isolates six zymovars were found. All V. cholerae serovar 01 strains were classified in the same zymovar except for some strains of environmental origin, which occurred in another zymovar. In V. fluvialis two zymovars were detected corresponding with biovars 1 and 2 of this organism. All isolates of V. parahaemolyticus gave the same enzyme type.

The technique of enzyme electrophoresis appears to be a useful tool in vibrio taxonomy and used in conjunction with other methods may aid in the elucidation of the systematics of the genus.
A Rapid Visual Test to Characterize Cholera Vibrios
Authors: SALLES C. A. , MOMEN H.
Published: March 2008

In an enzymatic reaction it was observed that lysates of Vibrio cholerae serovar 01 from human origin produced a reversal of the redox indicator while lysates of V. cholerae non‐01 serovar, and 01 serovar isolated from the environment in cholera‐free areas did not produce such change. This observation was utilized in a rapid visual test (RVT) which may be useful in the identification of cholera vibrios. There seems to be no correlation between RVT positives and toxin production. The composition of the media seems to be a major factor affecting the outcome of the test. The mechanism of the reaction is under study. Preliminary observations suggest participation of the oxidase system of V. cholerae, atmospheric oxygen and perhaps selective action of Triton X‐100.
The Potassium Iodide Method for Determining Protection Factors in Open‐fronted Microbiological Safety Cabinets
Authors: CLARK R. P. , GOFF M. R.
Published: March 2008

A method for determining operator protection factors in Class I and Class II microbiological safety cabinets and for evaluating product protection factors in Class II cabinets, is described. The technique employs an aerosol of potassium iodide droplets produced by a spinning disc generator together with special centripetal air samplers detecting any aerosol escape. The method meets the requirements of British Standard (BS) 5726 and is an alternative to the microbiological technique.

The method has been used to evaluate the performance of a number of safety cabinets in relation to the requirements of BS 5726.

Working procedures and unsuitable environments have been shown to prejudice the containment performance of open‐fronted cabinets by several orders of magnitude.

The relationship between inflow air velocity and protection factors in Class I safety cabinets has confirmed the optimum requirements defined in the British Standard.
The Enumeration, Isolation and Characterization of Sulphate‐reducing Bacteria from North Sea Waters
Authors: HARDY J. A.
Published: March 2008

Sulphate‐reducing bacteria present in sea water used for secondary recovery of oil in the North Sea were enumerated using a most probable number method. Numbers ranged from 0 to 90/ml. Seventeen strains were isolated from enrichments using either lactate or propionate in media containing yeast extract. Cytological, physiological, biochemical and nutritional characteristics were determined for 14 strains and the moles percentage guanine plus cytosine ratio determined for seven strains. Two morphological types were recognized based on size and spirilla formation but in many of the properties examined the strains were similar; Gram negative, non‐spore‐forming, desulfoviridin‐positive vibrios which contained cytochrome C3 and, therefore, corresponded to the genus Desulfovibrio. The range of GC values spanned 58.2 to 62.5% which substantiated the tentative identification of the isolates as strains of D. vulgaris.
The Sterility Testing of Aminoglycosides: A New Approach Using Enzymic Inactivation
Authors: SIMPSON ANN M. , BREEZE A. S.
Published: March 2008

The inactivation of various aminoglycosides prior to sterility testing has been studied. The preparation of the enzyme used in the inactivation, a 3‐N‐acetyl transferase of wide substrate specificity from Escherichia coli JR 225, is described. The enzyme is partially purified and some of its kinetic parameters described. The extent of the inactivation of the individual aminoglycosides can be related to the physiological efficiency of the enzyme. The lyophilization of the components of the inactivating system is successful when undertaken individually, but not together.
The Intracellular Water Activity of Bacteria in Relation to the Water Activity of the Growth Medium
Authors: CHIRIFE J. , FONTAN C. FERRO , SCORZA O. C.
Published: March 2008

Intracellular water activities (aw) calculated from the solute composition of various bacterial cells, are in good agreement with values derived from intracellular freezing point data. Further, and confirming literature results based on freezing points, the intracellular aw was found to be generally equal to or lower than that of the growth medium.
An Evaluation of the A‐1 Most Probable Number and the Anderson and Baird‐Parker Plate Count Methods for Enumerating Escherichia coli in the Sydney Rock Oyster, Crassostrea commercialis
Authors: YOOVIDHYA T. , FLEET G. H.
Published: March 2008

Two rapid methods were evaluated for enumerating Escherichia coli in the Sydney rock oyster, Crassostrea commercialis. The A‐1, most probable number (MPN) method gave results within 24 h but the Esch. coli counts obtained were considerably lower than those obtained by the more lengthy MPN method recommended by the Standards Association of Australia (SAA). The differences in counts were statistically significant at the 95% confidence level. The membrane‐overlay agar plate method of Anderson & Baird‐Parker produced direct counts of Esch. coli within 24 h. At the 95% confidence level, these counts were similar to those found with the SAA method. The Anderson & Baird‐Parker method was sensitive and accurate in the range of 2‐5 Esch. coli cells/g of oyster homogenate as would be required in the regulation of microbiological standards for oysters.
The Growth of Pseudomonas putida in AVTUR Aviation Turbine Fuel
Authors: WILLIAMS G. R. , CUMINS ELAINE , GARDENER A. C. , PALMIER MARIA , RUBIDGE T.
Published: March 2008

Bacteria isolated from aviation turbine fuel (AVTUR) grew rapidly using the jet fuel as the sole source of carbon and energy. One organism, identified as a Pseudomonas putida survived in the fuel phase for periods of up to one month. This organism grew on and oxidized a wide range of alkanes, with optimum growth occurring on octane. The mechanism of alkane metabolism in this organism was found to be ω‐oxidation followed by β‐oxidation.
Characterization of Bacteroides Species Isolated From Soft Tissue Infections in Cats
Authors: LOVE DARIA N. , JONES R. F. , BAILEY MARILYN
Published: March 2008

A total of 77 strains of Gram negative anaerobes belonging to the genus Bacteroides and isolated from 60 subcutaneous abscesses and 10 cases of pyothorax in cats, have been examined morphologically and biochemically. Colony pigmentation, gas chromatography and biochemical analysis placed them into two major categories‐those which produced pigmented colonies (Group 1) and those which failed to produce pigmented colonies after 14 d on laked blood agar (Group 2). All 29 strains in Group 1 produced acetic, propionic, isobutyric, butyric, isovaleric and succinic acids but failed to ferment carbohydrates, and were classified as B. asaccharolyticus. All organisms in Group 2 produced acetic, propionic, isobutyric, isovaleric and succinic acids and were divided into four categories based on indole production and bile tolerance. Designation to species was then decided on the basis of phenylacetic acid production and sugar fermentation tests. This sequence of analysis of results enabled confident speciation of some groups of these organisms despite some biochemical variation of the cat strains when compared to human type strains.
Identification of oral Neisseria species of animals
Authors: Dent V.E.
Published: March 2008

Ninety‐seven strains of presumptive Neisseria spp. obtained from the dental plaque of a wide variety of animals and 21 strains from culture collections were compared by physiological tests, enzyme electrophoresis and isoelectric focusing of proteins. Three physiological groups based on the fermentation of maltose and production of extracellular polysaccharide were established. The ability of strains within these groups to reduce nitrate and nitrite differed. The electrophoretic mobility of dehydrogenases and isoelectric focusing patterns of proteins were not, however, characteristic of species or physiological groups. It is difficult, therefore, to identify new isolates of Neisseria because the criteria for describing species overlap. A rapid spot test was devised to distinguish Branhamella catarrhalis from other Neisseria by the absence of glucose‐6‐phosphate dehydrogenase.
Enterotoxigenic staphylococci in Sri Lanka
Authors: Palasuntheram C. , Beauchamp M.S.
Published: March 2008

Two hundred and ninety‐three strains of Staphylococcus aureus isolated from clinical specimens were tested for enterotoxigenicity by the Optimum Sensitivity Plate (OSP) method. Thirty‐nine per cent produced enterotoxins A, B, C, D or E. Enterotoxin B was detected more often than the others. The OSP technique was found to be satisfactory for the detection of enterotoxigenic staphylococci.
Growth and toxin formation by Clostridium botulinum at low pH values
Authors: Smelt J.P.P.M. , Raatjes G.J.M. , Crowther J.S. , Verrips C.T.
Published: March 2008

Spores of Clostridium botulinum were found to initiate growth and to produce toxin in aqueous suspensions of soya protein at pH values as low as 4‐2 and in skimmed milk at pH 4.4. Most of the experiments were done with mixed cultures of CI. botulinum types A and B in the presence of two strains of Bacillus subtilis. The role of the latter organism was concluded to be to lower the oxygen content and the Eh of the suspensions. Toxin was produced at pH 4‐4 after 4 weeks of incubation at 30oC when either hydrochloric or citric acids were used as the acidulant and after 12 and 14 weeks when, respectively, lactic and acetic acids were used. Thus, amongst other factors the nature of the acid and not solely the pH value is an important factor in controlling the growth of Cl. botulinum at low pH. Pure cultures of Cl botulinum type A grew at 30oC under strictly anaerobic conditions and produced toxin at pH 4‐3 in the presence of hydrochloric acid.
The isolation of a fungal metabolite which exhibits antimicrobial synergy with sterigmatocystin
Authors: Perry M.J. , Adlard M.W. , Holt G.
Published: March 2008

A metabolite, which acted synergistically with sterigmatocystin to inhibit the growth of several Gram positive bacteria, has been isolated from several strains of Aspergillus nidulans. Preliminary characterization of this metabolite indicated that it was a high‐molecular‐weight glycoprotein. Dihydrosterigmatocystin, aflatoxin B, and aflatoxin Gt all failed to exhibit antimicrobial synergy with the glycoprotein. Thus, the synergy with the glycoprotein was specific for sterigmatocystin and the presence of the unsaturated bifuran moiety was shown to be essential to the antimicrobial action of the synergy.
A note on the performance of Rappaport's medium, compared with Rappaport‐Vassiliadis broth, in the isolation of salmonellas from meat products, after pre‐enrichment
Authors: Xirouchaki E. , Vassiliadis P. , Trichopoulos D. , Mavrommati CH.
Published: March 2008

Salmonellas were isolated from meat products using a slightly modified Rappaport's enrichment medium (R25), Rappaport‐Vassiliadis procedure (Rappaport's broth containing 10 ml instead of 30 ml of Malachite Green solution and incubated at 43oC instead of 37oC), and Muller‐Kauffmann's tetrathionate broth. From 255 samples, 89 were found positive with the Rappaport‐Vassiliadis procedure, 83 with the R25 broth, whereas only 43 were positive with Muller‐Kauffmann broth. It is concluded that the R25 medium may be used as an alternative to the more effective Rappaport‐Vassiliadis broth when the only available incubation temperature is 37oC.
Applications of a Serratia marcescens bacteriophage as a new microbial tracer of aqueous environments
Authors: Drury D.F. , Wheeler D.C.
Published: March 2008

A bacteriophage of Serratia marcescens was evaluated as a tracer in three appropriate aqueous environments and compared with an accepted tracer in two cases. The phage compared favourably with lithium chloride in demonstrating flow characteristics and retention times of various stages in the sewage treatment process. The phage exhibited virtually identical distribution in a marine harbour to spores of Bacillus subtilis var. niger (‘B. globigii’) 36–48 h after their addition to a sewage works' final effluent which entered an adjacent bay. Transit times of river water were accurately measured between two points under various flow conditions.
A method for estimating viability of aquatic bacteria by slide culture
Authors: Fry J.C. , Zia Talat
Published: March 2008

To estimate the viability of freshwater bacteria, slide cultures were prepared by spreading 10 μl of water, concentrated by centrifugation, over 1 cm2 of agar. After drying, a cover‐slip was placed on the agar. Following incubation, microcolonies and single cells were counted under a phase contrast microscope, and the viability estimated. Incubation at 10°C on casein‐peptone‐starch agar for 24 or 72 h provided the highest estimates of viability (ca 45%). Most microcolonies developed under these conditions and the total number of microcolonies and single cells did not decrease significantly during incubation. Several morphological types of bacteria were observed as both microcolonies and single cells. Most microcolonies consisted of two cells, although some larger ones were present. The method could be used as an alternative to the spread plate and other methods which assess viability from bacterial growth on agar.
Numerical classification of Rhodococcus equi and related actinomycetes
Authors: Goodfellow M. , Beckham A.R. , Barton M.D.
Published: March 2008

Eighty‐three strains received as Corynebacterium or Rhodococcus equi and marker cultures of Corynebacterium and Rhodococcus species were subjected to numerical phenetic analyses using 112 unit characters. The data were examined using the simple matching (SSM) and Jaccard (SJ) coefficients and clustering was achieved using the average linkage algorithm. Cluster composition was not markedly affected by the coefficient used or by test error, estimated at 2.9%. Most of the strains received as R. (C.) equi formed a distinct and homogeneous cluster in the aggregate Rhodococcus taxon, the strains of which were sharply separated from marker cultures of C. pseudotuberculosis and C. renale. The taxon R. equi was redescribed and Nocardia calcarea Metcalf & Brown reduced to a subjective synonym of R. erythropolis (Gray & Thornton) Goodfellow & Alderson.
A comparison of solid and liquid media for measuring the sensitivity of heat‐injured Salmonella typhimurium to selenite and tetrathionate media, and the time needed to recover resistance
Authors: Mackey B.M. , Derrick Christine M.
Published: March 2008

Sensitivity of heat‐injured Salmonella typhimurium to selenite and tetrathionate media was measured by viable counts in liquid and on agar‐solidified versions of these media and on nutrient media. All solid media, including the supposedly non‐inhibitory nutrient agar, were more inhibitory to injured cells than the corresponding liquid media. Catalase or pyruvate increased counts on nutrient agar to the level obtained in nutrient broth. Therefore nutrient agar plus pyruvate was the most suitable reference medium against which to compare recoveries on other media. Although recoveries of injured cells varied widely depending on the composition and physical state of the medium, this had a minor effect on estimates of repair time because resistance to all selective media was regained by the end of the lag phase.
Deoxyribonucleic acid homologies among strains of Bacteroides melaninogenicus and related species
Authors: Steenbergen T.J.M. van , Vlaanderen C.A. , Graaff J. de
Published: March 2008

Saccharolytic, black‐pigmented Bacteroides strains, which at present belong to the species Bacteroides melaninogenicus were classified on the basis of deoxyribonucleic acid (DNA) base ratios and DNA hybridization studies. These strains were divided into several DNA homology groups, which showed no or low mutual DNA homology. A DNA homology group with a percentage guanine plus cytosine (G + C) of 42–43% was formed by three strains of Bact. melaninogenicus subsp. melaninogenicus; the type strain of this subspecies, strain ATCC 25845, had about 60% DNA homology with this group. Strain ATCC 15930, which has been assigned to this subspecies, had a percentage G + C of 47% and showed no DNA homology with the former group. All strains of Bact. melaninogenicus subsp. intermedius had a percentage G + C of 39–45%. A DNA homology group was formed by eight strains of this subspecies. The type strain of Bact. melaninogenicus subsp. intermedius, ATCC 25611, showed relatively low DNA homology with this main DNA homology group. A strain of Bact. melaninogenicus subsp. intermedius serotype C1 showed no DNA homology with the other strains tested. Furthermore two strains labelled ‘Bact. melaninogenicus subsp. levii’ were found to form a distinct DNA homology group. On the basis of the DNA homology results, the strains, which at present are classified in the species Bact. melaninogenicus, were clearly distinguished from strains of Bact. asaccharolyticus and Bact. gingivalis, and also from strains of related non‐pigmented Bacteroides species.
Observations on the in vivo and in vitro competition between strains of Escherichia coli isolated from the human gut
Authors: Mason T.G. , Richardson G.
Published: March 2008

Regular exmination of Escherichia coli in faecal samples provided information about the outcome of competition in vivo and enabled two successful competing organisms to be selected for in vitro studies. A continuous flow culture technique was used in an attempt to reproduce the interactions that occurred between these two strains in the human gut. Some success was achieved in showing that changes in the chemostat environment, similar to those thought to be of significance in the gut, were followed by the establishment of the in vivo patterns of dominance.
The effect of environmental factors on the suspended bacteria in the Welsh River Dee
Authors: Nuttall D.
Published: March 2008

Water samples collected every 8 d from three sites on the Welsh River Dee over 29 months were examined chemically and morphologically and their heterotrophic activities assessed. Bacterial population estimates were regressed on 21 independent environmental variables using multiple linear regression analysis. Prediction equations calculated from 1975–1976 data accounted for 70% of the total variation from an upland site but only 40% for a lowland site. The validity of the prediction equations was examined by correlating the predicted and observed count data of 1977–1978. The correlations of plate count values were significant for the upper (r= 0.64, P < 0.001) and middle reach (r= 0.62, P < 0.01) sites but not significant for the lowland site. The direct count correlation was significant for all three sites. The permanganate value, a measure of organic matter, was the most dominant variable in the prediction equations and was shown by principal component analysis (PCA) to be linked to particulate matter and river flow. Prediction equations constructed from the PCA data accounted for less variation than the original equations but, in general, there was an agreement between the two methods of multivariate analysis. The logarithm of the heterotrophic potential (Vmax) from the lowland site was shown to be a linear function of temperature (r= 0.7, P < 0.001). A specific activity index calculated for the lowland site data gave a median value of 8.4 times 10‐10μg/h/bacterial cell and was highly sensitive to temperature change (r= 0.74, P < 0.001) whereas the median value for the upland site was 2.6 times 10‐10μg/h/bacterial cell and did not respond significantly to temperature change (r= 0.44, P > 0.05).
Role of the coat in resistance of bacterial spores to inactivation by ethylene oxide
Authors: Dadd A.H. , Daley Gabrielle M.
Published: March 2008

A study of spore morphology revealed an association between resistance to ethylene oxide and abnormal spore coat development and both characteristics were enhanced by selection and propagation of resistant survivors. After rupture of the coat, spores were sensitized to lysozyme but not to ethylene oxide. Resistance to ethylene oxide was increased following treatment of spores with ureamercaptoethanol‐alkali and decreased after treatment with urea. Germinated spores retained resistance to the sterilant and loss of resistance coincided with emergence of the vegetative cells.
The stability of Streptococcus mutans populations in the dental plaque of monkeys (Macaca fascicularis)
Authors: Beighton D. , Hayday Hazel
Published: March 2008

The Streptococcus mutans populations in the dental plaque of two groups of monkeys were examined. In the first group of 17 monkeys the proportion of Strep. mutans in the dental plaque increased when the monkeys were fed a cariogenic high sucrose (CHS) diet. The same predominant Strep. mutans serotypes were present in the plaque of these monkeys 12 and 25 months after the change to the CHS diet. A second group of 22 monkeys was caged in two communes. As a result of a change to the CHS diet one commune harboured a plaque flora in which Strep. mutans serotype e strains predominated and the second commune harboured a plaque flora in which Strep. mutans serotypes c and h predominated. On the basis of the results from these 39 monkeys three types of Strep. mutans populations were identified: (i) serotype e dominated; (ii) serotype c dominated; and (iii) serotypes c and h in varying proportions. It was not possible to predict which Strep. mutans population would become established in a given group of monkeys. Attempts to demonstrate transmission of Strep. mutans serotypes between pairs and larger groups of monkeys caged together were not successful over periods of up to 36 weeks. The implications of these observations on the use of monkeys as a model of human dental caries is discussed.
The heat resistance of ascospores of four Saccharomyces spp. isolated from spoiled heat‐processed soft drinks and fruit products
Authors: Put Henriëtte M.C. , Jong J. De
Published: March 2008

The heat resistance (D and z values) of four Saccharomyces spp., viz. S. bailii, S. cerevisiae, S. chevalieri, S. uvarum, was investigated by a previously described method (Put et al. 1977). The highest heat resistance was observed in ascospores of S. cerevisiae 175 showing a decimal reduction time or death rate constant at 60°C of 22.5 minutes. The average D60°C values of the remaining species were: S. bailii 10 min; S. chevalieri 13 min; and S. uvarum 1.5 min; while z values varied between 4.0 and 6.5°C. It can be postulated that there may exist some comparison between the mechanism of yeast ascospore and bacterial endospore heat resistance. However, (i) washed Saccharomyces ascospores cannot be stored at 5°C for a longer period than 2–3 weeks without loss of heat resistance; and (ii) ascospore heat survival curves are essentially not linear over the whole range, which may be due to some heterogeneity of the ascospore population tested. Besides, it was observed that the heat resistance (D60°C values) of the Saccharomyces ascospores proved to be 50–150‐fold higher than the D60°C values of the corresponding vegetative cells.
The incidence of Vibrio cholerae in water, animals and birds in Kent, England
Authors: Lee J.V. , Bashford D.J. , Donovan T.J. , Furniss A.L. , West P.A.
Published: March 2008

Between 1976 and 1979 several surveys were carried out in Kent, England, to establish the incidence of Vibrio cholerae in the aquatic environment. Vibrio cholerae occurred sporadically in all types of water during the summer but only in very low numbers in water containing <5 mmol Na+/litre. Highest numbers of up to 700 colony‐forming units/ml appeared regularly in static brackish water containing 25–200 mmol Na+/litre. They were not introduced by sewage contamination of the water and there was no correlation between the counts of Escherichia coli and V. cholerae. A wide range of serovars including O1 was isolated. Vibrio cholerae was not isolated from sheep faeces but was detected in 6% of cloacal swabs taken from gulls caught at times when V. cholerae could not be isolated from water. It was concluded that: the presence of these organisms in the environment in Kent does not present any significant risk to health; aquatic birds may be vectors of V. cholerae; V. cholerae occurs naturally in static brackish water.
Theory and programming of a computer identification system for coliform strains
Authors: Lefebvre B. , Gavini F.
Published: March 2008

Previous numerical studies on coliform enterobacteria strains enabled differentiation into two categories: faecal and aquatic or telluric enterobacteria. Here is described the theory and programming of a computer identification system devised to identify faecal coliform enterobacteria and newly described aquatic or telluric species.
Incidence of thermoduric psychrotrophs in milk produced in the west of Scotland
Authors: Johnston D. W. , Bruce J.
Published: March 2008

Thermoduric psychrotrophs were found in 27.2% of milk samples collected from 1040 farms in the west of Scotland. Of the micro‐organisms isolated 85.8% were identified as belonging to the genus Bacillus and 9.9% were assigned to the coryneform group. Bacillus cereus occurred most frequently and B. licheniformis and B. coagulans also occurred in significant numbers.
The production of plant cell wall polysaccharide‐degrading enzymes by hemicellulolytic rumen bacterial isolates grown on a range of carbohydrate substrates
Authors: Williams A.G. , Withers Susan E.
Published: March 2008

Several cultures of bacteria, isolated from the rumen, that were able to utilize plant cell wall structural polysaccharides were grown on a range of carbohydrate substrates and the activities of the principal polysaccharide‐degrading enzymes determined. The esterase activity was also monitored. The extent of hemicellulose degradation and utilization by the isolates was comparable with that of the hemicellulolytic type strains. Enzyme activities in all of the cultures examined were affected by the carbon source in the growth medium. Many responses were strain specific, although growth on glucose (or cellobiose and maltose to a lesser extent) resulted in reduced activities in most of the organisms examined, whilst polysaccharidic substrates resulted in higher levels of the appropriate polysaccharidase. However, enzyme activity was detectable in some isolates after culture on mono‐ or disaccharides in the absence of the principal or related polysaccharide substrate.
The occurrence and properties of Gemmiger formicilis and related anaerobic budding bacteria in the avian caecum
Authors: Croucher Susan C. , Barnes Ella M.
Published: March 2008

Gram negative budding bacteria with a characteristic morphology have been observed in the caeca of chickens, turkeys, ducks and guinea fowl at levels between 0–4 and 24% of the total flora. Using strict anaerobic techniques a detailed study has been made of the organisms isolated from the caeca of chickens aged between 15 and 44 d. The majority of isolates were identified as Gemmiger formicilis, the strains being divided into twomajor types according to the relative amounts of butyric acid and lactic acid produced from glucose. A second group of isolates could not be related to any known species.

Amongst properties of ecological interest studied were limiting temperatures for growth, ammonia utilization, ability to utilize various carbon sources and survival in environments outside the intestine.

Attempts to produce a selective medium for the isolation of these organisms when present at less than 2% of the total flora were unsuccessful.
The use of solid medium to study effects of cadmium, copper and zinc on yeasts and yeast‐like fungi: applicability and limitations
Authors: Gadd G.M.
Published: March 2008

A defined solid medium has been used to examine the responses of Aureobasidium pullulans, Saccharomyces cerevisiae and Sporobolomyces roseus to cadmium, copper and zinc. Experiments where aliquot volumes of metal salt solutions were added to wells in the centre of agar plates revealed marked differences between these organisms. The yeast‐like fungus A. pullulans was the least sensitive but S. cerevisiae was more sensitive to cadmium than zinc: the reverse was true for S. roseus. Quantitative data, which complemented the qualitative results, were obtained by measurement of metal concentrations in the plates.
The Rappaport—Vassiliadis (RV) enrichment medium for the isolation of salmonellas: An overview
Authors: Vassiliadis P.
Published: March 2008

In 1976 two major modifications were introduced in the composition and use of Rappaport's magnesium chloride—malachite green enrichment medium for salmonellas. One modification consisted of the reduction to one‐third of the amount of malachite green contained in the original formulation of Rappaport's medium, and the other in the incubation at 43 instead of 37°C. Since 1980, the modified medium incubated at 43°C is known as RV (Rappaport—Vassiliadis) enrichment medium for salmonellas.

From 1977 to 1981, in eleven studies, the RV enrichment broth has been compared to the standardized Muller‐Kauffmann tetrathionate broth (MK broth) recommended as a reference method by the International Standards Organization, for the isolation of salmonellas from meat products, after pre‐enrichment in buffered peptone water. In all these studies the RV broth was superior to the MK broth in the isolation of salmonellas from naturally contaminated meat products (bovine minced meat, pork sausages, mesenteric lymph nodes, chicken carcases), sewage and faeces of healthy pigs, after pre‐enrichment in buffered peptone water. This superiority was statistically significant in seven of the eleven trials. Furthermore, in three more investigations the RV medium was compared with Oxoid selenite broth, with Difco tetrathionate broth and Difco selenite‐cystine broth. In all these three investigations the RV medium was superior for isolation of salmonellas, after pre‐enrichment, from naturally contaminated meat products and animal feeds. The superiority was statistically highly significant.

When dealing with meat products, the RV medium in 10 ml volume inoculated with 0.1 ml of the pre‐enrichment medium, proved to be as effective as the RV medium in 100 ml volume, inoculated with 1 ml of pre‐enrichment medium, and clearly superior to the MK broth in 100 ml quantity.

In all these studies involving enrichment in RV medium, MK broth, Difco tetrathionate broth, Oxoid selenite broth, incubated at 43°C and Difco selenite‐cystine broth incubated at 37°C, the RV medium proved to be highly specific. This means that the RV medium inhibits much more strongly the competing organisms, (including ‘Proteus hauseri’) which are lactose‐ and sucrose‐negative on the selective media and which may produce salmonella‐like colonies.
Prevention of drug‐resistant Escherichia coli colonization in chickens by treatment with a faecal fluid
Authors: Nakamura M. , Yoshimura H. , Keda T. , Sto S.
Published: March 2008

This study was performed to prove that intestinal colonization in chickens by resistant Escherichia coli strains present in the environment might be prevented when faeces in which sensitive E. coli strains were dominant was administered to newly hatched chicks. The appearance of resistant E. coli strains was markedly reduced. Escherichia coli O49:H12 was the sensitive E. coli strain which formed the major colonizer in the intestinal tract. In young chickens, this strain persisted as a major component, and even when it was a minor colonizer in the faecal fluid administered, it appeared as a major component soon afterwards. This strain is considered to be a good colonizer in the gut of young chickens.
Suitability of oven‐dried root nodules for Rhizobium strain identification by immunofluorescence and agglutination
Authors: Somasegaran P. , Woolfenden R. , Halliday J.
Published: March 2008

Legume root‐nodules, dried at oven temperature (70°C for 48 h) were suitable for Rhizobium strain identification by immunofluorescence and agglutination. The fluorescence of bacteroids of R. japonicum, R. leguminosarum, R. meliloti, R. phaseoli, and Rhizobium spp. from oven‐dried nodules was the same as those from frozen, desiccated, or nodules dried at room temperature (28°C). Oven‐dried nodules did not require further steaming for agglutination. Bacteroid agglutinations gave 2–16 fold lower titres than those of the cultured cells. Fresh and oven‐dried soybean rhizobia from a mixed inoculation gave exactly the same results when identified by immunofluorescence or agglutination.
A numerical taxonomic study of species of Vibrio isolated from the aquatic environment and birds in Kent, England
Authors: West P.A. , Lee J.V. , Bryant T.N.
Published: March 2008

A numerical taxonomic study has been carried out to confirm the identity of strains of the family Vibrionaceae isolated during an ecological study. A total of 237 strains were studied including 148 from the aquatic environment, 6 from estuarine birds, 1 from sheep faeces, and 61 control cultures. Duplicates of 21 of the strains were randomly selected and included to estimate test and operator error. Taxonomic resemblance was estimated on the basis of 148 characters using Euclidean distance. The taxonomic position of some strains was reevaluated using the pattern difference coefficient. Strains were clustered by three methods, all of which gave similar results. The estimated average probability of test error was 1.5%. Strains previously identified as Vibrio anguillarum fell into four distinct phenons corresponding to V. anguillarum biovar I, ‘V. anguillarum biovar II’, V. diazotrophicus, and strains pathogenic to oyster larvae. The latter group characteristically degraded xanthine and probably represents a new species. The phenon corresponding to V. cholerae included the type strain, strains of human origin, and strains isolated in the United Kingdom from birds and the aquatic environment. Some strains of V. cholerae were luminous. Other phenons were identified as V. metschnikovii, V. fluvialis, and Aeromonas spp.
Subcellular fractionation of the Gram negative rumen bacterium, Butyrivibrio S2, by protoplast formation, and localisation of lipolytic enzymes in the plasma membrane
Authors: Hazlewood G.P. , Cho K.Y. , Dawson R.M.C. , Munn E.A.
Published: March 2008

Treatment of the anaerobic, Gram negative general fatty acid auxotroph Butyrivibrio S2 with lysozyme in low molarity buffers resulted in the formation of protoplasts, some of which retained the original rod‐shaped morphology of the organism. The protoplasts were stabilised by the presence of Mg2+ ions. Most of the phospholipase A and C and galactolipase activity of the cells was retained by the protoplasts. Electron microscopy and chemical markers were used to monitor the separation of plasma membrane and cell wall fragments by density gradient centrifugation after osmotic lysis of protoplasts. Phospholipase and galactolipase activities were demonstrated in a subcellular fraction which contained only fragments of plasma membrane.
A note on the determination of antibiotic susceptibility of invasive strains of Proteus by a simple agar dilution method
Authors: Zemelman R. , Gonzalez C. , Merino C. , Bello H. , Mondaca M.A.
Published: March 2008

A method is described for testing antibiotic susceptibility of invasive and non‐invasive micro‐organisms in which strains are grown on small agar discs.
Production and partial purification of a peptide antibiotic from Staphylococcus epidermidis
Authors: Eady E. Anne , Holland K.T. , Cunliffe W.J.
Published: March 2008

When grown on solid or in liquid Brain Heart Infusion at 37°C, Staphylococcus epidermidis NCIB 11536 produced antibiotic activity against a wide range of Gram positive bacteria. Production was influenced by aeration, pH, glucose concentration and specific growth rate. Inhibitory activity could be concentrated by ammonium sulphate precipitation (30–55% saturation). On Sephadex G50 using 0.05 mol/1 sodium phosphate buffer, pH 6.0, two peaks of antibiotic activity were detected. The first peak eluted with the void volume (Kd= 0) and the second peak was retained by the gel (Kd= 0.73–0.77). These two substances did not represent the monomeric and polymeric forms of a staphylococcal bacteriocin. The low mol. wt inhibitor, which was responsible for over 95% of the recovered activity on Sephadex G50, could be partially purified by a combination of gel filtration on Biogel P2 and ion‐exchange chromatography on Sephadex C‐25. Yields were increased by combining these two steps into a single procedure (duocolumn). The semi‐purified inhibitor was desalted using Sep‐pak C18 cartridges. Biological activity was resistant to enzymic denaturation except by high concentrations of trypsin (50 units/μg, 3 h, 25°C). This peptide antibiotic is different from any previously described staphylococcal inhibitors.
A note on the use of a pocket‐calculator to work out MPN‐values
Authors: Deschacht W.
Published: March 2008

The possibilities of computing MPN‐values were evaluated; and a program was developed to run on a small programmable pocket‐calculator. The mean introduction time of the data amounts to 9.4 s and the time needed to key in a significant number and to calculate the MPN‐value can be estimated by the equation: Time (s) = (32/REF) + 92.64. Introducing a REF‐value of one results in a time of two minutes, which is too long to drop the use of tabulated values. The agreement between calculated and tabulated figures is good.
Characterization of commercial yeast strains by flow microcalorimetry
Authors: Perry B.F. , Beezer A.E. , Miles R.J.
Published: March 2008

A flow microcalorimetric procedure has been developed for the characterization of representative strains of Saccharomyces cerevisiae and Sacch. uvarum (carlsbergensis) used in the food industry. Growth in a chemically defined medium containing single and mixed sugars gave reproducible and characteristic power‐time curves. The technique is proposed as a rapid alternative method for the characterization of yeast strains selected for commercial use.
Inhibition of heterotrophic and autotrophic nitrification in bacterial cultures by carbaryl and 1‐naphthol
Authors: Ramakrishna C. , Sethunathan N.
Published: March 2008

A carbamate insecticide, carbaryl, and its hydrolysis product, 1‐naphthol, inhibited nitrification by a heterotrophic bacterium, a Pseudomonas sp., at a concentration of 50 μg/ml and by chemoautotrophic bacteria, a Nitrosomonas sp. and a Nitrobacter sp., at a concentration of 10 µg/ml, in pure cultures.
Dynamics of salmonella isolation with modified Rappaport's medium (R10)
Authors: Schothorst M. van , Renaud A.M.
Published: March 2008

Enhanced growth of salmonellas in Rappaport's medium as modified by Vassiliadis et al. (1976) after pre‐enrichment in buffered peptone water during the first 6 h was obtained by replacement of tryptone by soya peptone. The competing bacteria, i.e. those which grow on brilliant green agar and which may interfere with the isolation of salmonellas when Rappaport's medium (R10) incubated at 43°C is used for enrichment were inhibited or reduced in numbers when the normal amount of 5 g soya peptone/litre was used. When the amount was increased to 10 g/l, growth occurred, mainly of Enterobacter and Klebsiella species. The isolation of salmonellas was found to be largely dependent on the number and the ratio of their competitors. Every measure taken to reduce the number of competitive bacteria increases the possibility of isolating salmonellas. This explains the effect of improved selectivity of Rappaport's medium when small inocula are used. Rapid onset of growth of salmonellas by employing soya peptone introduces the possibility of using shorter incubation times than 48 h.
Isolation and characterization of a Lactobacillus plantarum bacteriophage isolated from a meat starter culture*
Authors: Trevors Karen E. , Holley R.A. , Kempton A.G.
Published: March 2008

Morphological characterization of a bacteriophage isolated from the Lactobacillus plantarum portion of a commercial meat starter culture showed that the isolate, phage fri, belonged to the Bradley group A bacteriophages. It had a regular six‐sided head (90 nm diameter), and a contractile tail (190 nm in length). Short tail fibres were observed at the distal end of the sheath. Fluorescent staining with acridine orange indicated that phage fri contained double‐stranded DNA. The resistance to high concentrations of either chloroform or ether showed that its lipid content was negligible. Heat lability was demonstrated by inactivation of a phage fri population within 10 min at 60°C and within 5 min at 70°C. It tolerated pH levels of 3.0–8.0 and exhibited greater stability in the acid region than did its host strain. The latent and rise periods were both 75 min, and the average burst size 200 pfu/cell. Sensitivity was limited to the Lact. plantarum strain of only one manufacturer of the commercial meat starters investigated.
Purification and characterization of a new proteolytic enzyme produced by Aeromonas salmonicida
Authors: Mellergaard S.
Published: March 2008

A proteolytic enzyme produced by the fish pathogen Aeromonas salmonicida was isolated and purified. It showed the following characteristics: temperature optimum at 48°C, pH optimum at pH 9 and a molecular weight of 87 500. The enzyme was inhibited by phenylmethanesulphonylfluoride (PMSF) indicating it to be a serine protease.
A note on the isolation and enumeration of bacteria which deposit and reduce ferric iron
Authors: Jones J.G.
Published: March 2008

Media and methods suitable for the isolation of iron‐depositing and iron‐reducing bacteria from aquatic habitats are described. Higher MPN estimates were obtained, and a greater variety of bacteria isolated, when the media were made up in a semi‐solid form with a final agar concentration of 0.25%.
Quality assurance of selective culture media for bacteria, moulds and yeasts: an attempt at standardization at the international level
Authors: Mossel D.A.A. , Laarhoven Trees M.G. Bonants‐Van , Ligtenberg‐Merkus Anniek M.Th. , Werdler Maria E.B.
Published: March 2008

To facilitate monitoring of culture media, a simple quantitative streaking technique, implying ever‐decreasing numbers of colony‐forming units per surface area, as in spiral plating, was developed. The procedure evaluates, in quantitative terms, the ability of media (1) to support the formation of colonies by organisms that it was designed to grow and (2) to resist colonization by organisms that it is expected to suppress. The procedure was therefore termed ecometric evaluation. The ecometric results appeared to agree well with observations made on productivity and selectivity of the media studied during routine examination of specimens.

These encouraging results prompted further, rigorous standardization of ecometry. A template was developed to standardize inoculation and the depth of the agar was controlled to within ± 10%. Finally the attributes of the inocula used were accurately defined.

The standardized ecometric technique has been found useful for the following purposes: (1) to assess the practical significance of the inhibitory effect of gentamicin observed in some moulds and yeasts (this was solved by replacing poorer basal media by one particular richer modification, viz. yeast morphology agar); (2) the development of a blood‐free selective enumeration medium for Campylobacter jejuni, i.e. sulphide iron motility agar plus the combination of antibiotics suggested by Skirrow (1977); and (3) verification of the absence of antimicrobial activity of enzyme preparations, e.g. catalase, used in culture media to remedy sublethal damage in certain groups of bacteria.

Ecometric evaluation can now be recommended for (1) routine monitoring of consignments of dehydrated or ready‐to‐use, purchased media; and (2) in‐house checking of the functioning of medium preparation departments. Only occasionally is it necessary to use conventional counting techniques to confirm the results.
Rapid method for selecting appropriate solid media for the enumeration of aerobic micro‐organisms
Authors: Richard J. , Andersen Hanne Møller , Gratadoux J.J.
Published: March 2008

A quick and cheap method for selecting appropriate solid culture media has been devised. It consists in the rapid picking of fragments of test colonies with the aid of a rubber strip in which pins are fixed in parallel, dispensing up to 8 colonies simultaneously in the wells of a Microtiter plate and streaking 4 strains at the same time on square Petri dishes containing the media under comparison. The approximate diameters of well‐isolated colonies are measured with the aid of a series of calibrated spots. The results corresponded with those given by the spiral plate method used as a reference for colony count and diameter measure.
Identification of chemical constituents of tomato juice which affect the heat resistance of Lactobacillus fermentum
Authors: Juven B.J. , Ben‐Shalom N. , Weisslowicz H.
Published: March 2008

Pectins appear to be the main factors in tomato juice which are associated with the protection of Lactobacillus fermentum against destruction or injury by heat. Hydrolysis of pectins by enzymic action makes the cells more vulnerable to heat.