bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of susceptibility of Staphylococcus aureus to methicillin by luciferim‐luciferase assay of bacterial adenosine triphosphate
Authors: McWalter P.W.
Published: March 2008

McWalter, P.W. 1984. Determination of susceptibility of Staphylococcus aureus to methicillin by luciferin‐luciferase assay of bacterial adenosine triphosphate. Journal of Applied Bacteriology, 56, 145–150.

Susceptibility of 50 strains of Staphylococcus aureus to methicillin was determined by disc diffusion, minimum inhibitory concentration (MIC) test and luciferin‐luciferase assay of bacterial adenosine triphosphate (ATP). ATP concentration time curves calculated on eight strains (four sensitive, four resistant) incubated at 30d̀C indicated 2.5 h as the optimum time for determination of methicillin susceptibility. The ATP concentration and relative light unit (RLU) value of each test broth (antibiotic‐containing), expressed as a percentage of its own control broth (antibiotic‐free) indicated values of < 30% for ATP and < 40% for RLU to be indicative of methicillin sensitivity. Single time point ATP assays carried out on the 50 strains after 2.5 h at 30d̀C correlated exactly with disc diffusion and MIC. Luciferin‐luciferase assay of bacterial ATP appeared to be a reliable, rapid technique for determining the susceptibility of Staph. aureus to methicillin.
Plasmid profiles of Staphylococcus aureus causing bovine mastitis
Authors: Baumgartner A. , Nicolet J. , Eggimann M.
Published: March 2008

A. Baumgartner, J. Nicolet & M. Eggimann 1984. Plasmid profiles of Staphylococcus aureus causing bovine mastitis. Journal of Applied Bacteriology56, 159–163.

Plasmid profiles of Staphylococcus aureus, isolated from herds affected with chronic bovine mastitis, are heterogeneous, as shown by the study of 85 strains from 18 different farms. The strains isolated within a herd sometimes show related plasmid patterns, although even strains isolated from different quarters of the same udder may show variations in their plasmid content. Strains without antibiotic resistance are frequently free of plasmids. Therefore, the existence of mastitis Staph. aureus virulence plasmids is unlikely. Staphylococcus aureus, resistant to penicillin and streptomycin from 9 different farms show related plasmid patterns. This result confirms a geographic spread of certain mastitis Staph. aureus strains.
Cryosensitivity of Escherichia coli and the involvement of cyclopropane fatty acids
Authors: Calcott P.H. , Oliver J.D. , Dickey K. , Calcott Katherine
Published: March 2008

Calcott, P.H. Oliver, J.D. Dickey, K. & Calcott Katherine, 1984. Cryosensitivity of Escherichia coli and the involvement of cyclopropane fatty acids. Journal of Applied Bacteriology56, 165–172.

Strains of Escherichia coli proficient and deficient in cylopropane fatty acid synthesis were compared for fatty acid content, cryosensitivity, presence of freeze‐thaw‐induced wall and membrane damage, resistance to detergent‐stimulated lysis and tolerance to salt and detergents during growth. The mutant populations synthesized much less cyclopropane fatty acids and were more resistant than the wild type to freezing and thawing in saline only, exhibiting less viability loss and less wall and membrane damage. While the resistance of the mutants to NaCl was unaltered, their detergent resistance was decreased under both growth and non‐growth conditions. Although these physiological changes were associated with a lower cyclopropane fatty acid content in the mutant strains, it is proposed that the responses were due to the altered membrane fluidity of the mutants due to changes in their unsaturated fatty acid content.
The relationship of plasmid number to growth, acid tolerance and symbiotic efficiency in isolates of Rhizobium trifolii
Authors: THURMAN N.P. , LEWIS D.M. , JONES D. GARETH
Published: March 2008

Strains of Rhizobium trifolii isolated from 21 different sites in Wales were characterized for growth rate, acid and aluminium tolerance, symbiotic efficiency and plasmid content. Plasmid number ranged from 2 to 10 per isolate but it was not correlated with soil pH or altitude of the locality of isolation. Neither plasmid number nor the pH of the site of isolation affected growth in acid medium or aluminium sensitivity. Plasmid number was positively correlated with growth rate in pure culture (P > 0.001) but isolates with high plasmid numbers were inefficient in their nitrogen‐fixing ability on white clover. The possible role of plasmids in terms of competitive ability is discussed.
Ammonium as an alternative nitrogen source for hydrogen producing photobacteria
Authors: SEGERS L. , VERSTRAETE W.
Published: March 2008

Ammonium is known to inhibit nitrogenase activity, but at low concentrations it may support nitrogenase activity. This work describes the effect of different concentrations of NH+4 as the N‐source for growth and particularly for nitrogenase‐based production of hydrogen from malate, butyrate and lactate. Two different Rho‐dopseudomonas strains (ATCC 23782 and ST 407) were tested. Best growth was observed in the lactate‐NH+4 media. Photoproduction of H2 for cells grown with low levels (3.8 mmol/1) of NH+4 equalled that of cells grown with glutamate as N‐source.
Putrescine and cadaverine formation in vacuum packed beef
Authors: EDWARDS R.A. , DAINTY R.H. , HIBBARD C.M.
Published: March 2008

Bacterial numbers, putrescine and cadaverine concentrations and pH were measured at regular intervals during the chill storage of vacuum packed beef. Odours on opening the packs were also assessed. Cadaverine concentration increased more rapidly than that of putrescine and measurable increases were evident before maximum bacterial numbers were attained and before any permanent off‐odours were detected. Diamine concentrations correlated better with total viable count (TVC) than with counts of Gram negative organisms.
The development of a formulation for radiation‐sterilizable urea broth
Authors: EISENBERG E. , JACOBS G.P.
Published: March 2008

Urea broth, a medium used for the identification of the genus Proteus, was sterilized by gamma radiation, using radiation doses of 1–1mD5 Mrad. The radiation‐sterilized medium, modified by adding sodium ascorbate and increasing its phenol red and yeast extract content, performed as well as the commercial formulation prepared aseptically, when tested with different Proteus and non‐Proteus species. Gamma‐irradiation appears to be an attractive and economical method for sterilizing nutrient media in sealed tubes, avoiding the risk of contamination during processing
The ecology of Escherichia coli in market calves fed a milk‐substitute diet
Authors: HINTON M. , HEDGES A.J. , LINTON A.H.
Published: March 2008

Dynamic changes in the Escherichia coli population in the calf gut were studied over 21 days in a group of 18 intensively‐reared market calves. Isolates were identified by O‐serogrouping, biotyping and resistogram patterns. Seventy O‐serogroups were identified among nearly 3000 E. coli isolates examined and these were subdivided into 416 strains by means of their biotype and resistogram. Seventy‐five per cent of these strains were detected only once or twice, which points to the continual replacement of the E. coli flora with strains that showed low persistence in the gut. The rise in the frequency of antibiotic resistance observed during the study was not due to a change in the proportion of resistant to sensitive strains in the gut flora. It was a consequence of the displacement of the original flora by multiply‐resistant strains, which presumably originated from the calves' environment.
The relation between dosage, bacterial growth and time for disease response during infection of bean leaves by Pseudomonas syringae pv. phaseolicola
Authors: ERCOLANI G.L.
Published: March 2008

Pseudomonas syringae pv. phaseolicola 1L3 was infiltrated at a dosage of 0mD5 to 512 times the median effective dose (ED50) into the leaves of two bean cultivars, Borlotto di Vigevano (ED50 15 bacteria) and Saluggia (ED50 34 bacteria). The distributions of time for production of disease symptoms after inoculation with up to 64 ED50 were in agreement with those predicted by the simple birth‐death model for microbial infection. Individual times of response to higher doses were longer and more widely distributed than expected from the model. Growth curves of bacteria in leaves inoculated with 16, 64 or 512 ED50 could be viewed conventionally as a sequence of an exponential phase, a phase of decelerating growth and a stationary phase. Viable counts, however, were also compatible with parabolic population trends during the period preceding, accompanying and immediately following the appearance of disease symptoms. Bacterial growth parameters estimated from response times and infectivity titration data were consistent with those calculated from viable counts in vivo.
A note on the pectinolytic enzymes of Lachnospira multiparus
Authors: SILLEY P.
Published: March 2008

The identification of pectinolytic enzymes from two strains of Lachnospira multiparus grown on media containing pectin with differing degrees of methylation as the carbon source was investigated. Both pectinesterase and lyase activity were determined but there was no evidence of polygalacturonase being present as either an extracellular or intracellular enzyme.
Colonization of components of a model hot water system by Legionella pneumophila
Authors: SCHOFIELD GERALDINE M. , Locci R.
Published: March 2008

A model hot water distribution network was seeded with a virulent strain of Legionella pneumophila serotype 1. Ten weeks after inoculation, components of the system, which include aluminium discs, copper, stainless steel, silicone tubing, rubber and glass beads, were examined for colonization by L. pneumophila. The samples were stained with fluorescein‐labelled antibodies to the strain and were examined with scanning electron microscopy. Colonization, which was accompanied by copious quantities of a slime‐like debris, was heaviest on the rubber and least on the copper. Adherence to silicone tubing and stainless steel was observed.
Regulation of syringomycin synthesis in Pseudomonas syringae pv. syringae and defined conditions for its production
Authors: GROSS D.C.
Published: March 2008

Production of the phytotoxin, syringomycin (SR), by Pseudomonas syringae pv. syringae strain B301D was regulated by both iron and inorganic phosphate similar to that of many bacterial secondary metabolites. Iron concentrations of 2 µmol/1 or more in deferrated potato‐dextrose broth (PDB) resulted in the production of 1024 SR units/ml, a yield comparable to that produced in non‐deferrated PDB. Moreover, production of one SR unit required approximately 0†4 ng of available FeCl3. No SR was produced by strain B301D in deferrated PDB despite growth nearly identical with that of B301D in deferrated PDB supplemented with 10 µmol/1 FeCl3. Furthermore, a phosphate concentration of 1 mmol/1 or more was suppressive to SR production. Of the amino acids tested, L‐histidine at a concentration of ca 20 mmol/1 was the most effective nitrogen source for SR synthesis under defined conditions. Based on these observations, a synthetic medium, SR minimal, was formulated for SR or syringotoxin production by representative strains of Ps. syringae pv. syringae. The regulation of phytotoxin production is discussed in relation to pathogen survival and virulence.
Method for isolating cyanobacteria‐lysing streptomycetes from soil
Authors: WHYTE L.G. , MAULE A. , CULLIMORE D.R.
Published: March 2008

A new technique is described for the isolation and enumeration of cyanobacteria‐lysing Streptomyces spp from soil or water. Two cyanobacteria, Anabaena cylindrica (ACTT 27899) and Tolypothrix tenuis (ATCC 27914) were used as the test organisms. Ten‐day‐old cyanobacterial cultures were vacuum‐filtered to form a lawn on a 7 cm Whatman No. 1 filter paper which was then supported on Allen's agar. When the lawn was inoculated with dilutions of a heavy clay prairie soil and incubated at 27 PT 1dEC under constant illumination, white or grey colonies of streptomycetes grew. These colonies were surrounded by zones where a yellowing and lysis of the algal cells occurred. Streptomyces achromogenes was identified as a major lytic species within a population of 5 times 103 plaque‐producing streptomycetes/g (dry weight) soil.
A comparison of the fluorescent ELISA and antibiotic resistance identification techniques for use in ecological experiments with Rhizobium trifolii
Authors: RENWICK ANNABEL , JONES D. GARETH
Published: March 2008

The fluorescent ELISA technique for the identification of bacteria was compared with antibiotic resistant mutants as marker systems for use with Rhizobium trifolii in root nodules and in soil. With an effective(CP3B) and an ineffective (R4) strain as a mixed 1:1 inoculum, there was a highly significant correlation (P < 0.001) between the two techniques when the plants were grown at pH 5.5 when the majority of nodules were inhabited by the effective strain. At pH 6.5, where the ineffective strain predominated in the nodules, there was no correlation. The reason was that 85% of R4 nodules had volumes less than 0.1 mm3 with bacterial numbers obviously below the necessary threshold for detection using the serological method. Both methods were efficient at enumerating rhizobia from soils although the recovery rate from a brown earth soil was significantly higher than from a peat soil. Fluorescent ELISA was able to detect rhizobia at 8.0 times 105 cells/ml soil suspension (1 g soil to 10 ml water) in the brown earth soil and at 2.0 times 105 cells/ml in the peat soil. The results are discussed in terms of the limitations of both techniques in ecological studies.
The suitability of a membrane diffusion growth chamber for studying bacterial interaction
Authors: CRUMP J.E. , RICHARDSON G.
Published: March 2008

Rates of diffusion of nutrients and metabolites through 0.1 µm pore diameter polycarbonate membranes are so low that the use of membrane‐separated systems to study bacterial interaction seems to have little application. Effective nutrient availability throughout the system is very dependent on membrane area/medium volume ratio. An attempt to demonstrate a known interaction in the membrane diffusion chamber was not successful.
Preparation and properties of Vibrio cholerae antifimbrial antibody
Authors: AL‐KAISSI ELHAM , MOSTRATOS ANN
Published: March 2008

The presence of fimbriae on the Vibrio cholerae strains used was assessed by pellicle formation, haemagglutination activity and electron microscopy. Fimbrial suspensions were prepared by shearing them off the organisms, then separating them from other components by absorbing them on to rabbit red blood cells. Rabbits were then immunized with the fimbrial‐red cell suspensions and the antibodies evoked were titrated by haemagglutination inhibition, agglutination, vibriocidal and immobilization techniques.
A note on a membrane filtration method for the concentration and enumeration of bacteriophages from water
Authors: PURDY R.N. , DANCER B.N. , DAY M.J. , STICKLER D.J.
Published: March 2008

A membrane filtration method is described for the recovery and enumeration of bacteriophage from water. The method is conveniently used in the field and requires no complex or expensive equipment.
Book Reviews
Authors: NEWSOM S.W.B.
Published: March 2008

Book reviewed in this article:

OCCUPATIONAL MYCOSES (1983) Edited by A.F. DiSalvo. 247 pp. Philadelphia: Lea & Fibiger. 27.00.
Tinopal AN as a selective agent for the differentiation of phytopathogenic and saprophytic Pseudomonas species
Authors: PHILLIPS MARY K. , ROBERTS MURIEL E. RHODES , KELL D.B.
Published: March 2008

The selective toxicity of the respiratory inhibitor Tinopal AN (1,1‐bis (3,N‐5–dimethylbenzoxazol‐2‐yl) methine p‐toluene sulphonate) towards phytopathogenic bacteria was investigated further and in general was confirmed using more than 160 additional strains of Pseudomonas spp. The mechanism(s) of the resistance shown by saprophytic fluorescent pseudomonads were studied to elucidate the differences between resistant saprophytic and sensitive phytopathogenic Pseudomonas species. Damage to, or partial removal of the cell wall of Tinopal AN‐resistant Pseudomonas aeruginosa, resulted in a marked Tinopal AN‐sensitivity, as judged by the ability of Tinopal AN to inhibit oxygen uptake. Furthermore, removal of part of the lipo‐polysaccharide (LPS) component of the outer membrane also resulted in sensitivity. Mutants of Ps. aeruginosa with modified outer cell walls were tested for their reactions towards Tinopal AN, and two cell wall lipopolysaccharide (LPS) mutants of Escherichia coli (env Al) and Salmonella typhimurium (rfa) were, in contrast to the wild‐type strains, found to be sensitive towards Tinopal AN. The results therefore suggest that the resistance of saprophytic pseudomonads towards Tinopal AN is due (at least in part) to the selectively permeable properties of the outer membrane of the cell wall. The usefulness of Tinopal AN for screening potentially phytopathogenic strains of Pseudomonas was confirmed.
Towards microbiological quality assurance in radiation sterilization processing: simulation of the radiation inactivation process
Authors: FITCH F.R. , DOOLAN P.T. , DWYER J. , DWYER V.M. , HALLS N.A. , TALLENTIRE A.
Published: March 2008

A method is developed for computer simulation of the inactivation of microorganisms on items by irradiation. It is shown that in a population of items subjected to increasing doses of radiation the proportion contaminated approaches the appropriate Limiting Case, outlined in a previous paper, as numbers of organisms are decreased by inactivation. The behaviour of populations of items having different proportions of ‘spikes’ (high bioburden levels) is considered.
A note on the biocidal properties of Caro's acid triple salt
Authors: BALDRY M.G.C.
Published: March 2008

Caro's acid triple salt (CATS) was found to be bactericidal under acidic or neutral conditions. Although CATS was ineffective against yeasts and bacterial spores, mixtures of CATS and propan‐2‐ol were rapidly sporicidal in non‐alkaline solutions. The sensitivity of yeasts to propan‐2‐ol was increased by either preliminary or simultaneous exposure to CATS.
Potential sites of geosmin production by streptomycetes in and around reservoirs
Authors: WOOD S. , WILLIAMS S.T. , WHITE W.R.
Published: March 2008

Water from several oligotrophic reservoirs of the North West Water Authority at Longridge, Lancashire, supported only sparse growth of streptomycetes isolated from the reservoirs. Growth was enhanced by nutrient‐amendment of the water and one common isolate, identified as Streptomyces albidoflavus, produced geosmin in water which was supplemented with sufficient concentrations of available carbon, nitrogen and phosphorus. The minimum concentrations required for geosmin production were higher than those recorded in natural reservoir water. Synthesis of geosmin in water also required a minimum temperature of about 15dEC. Sterilized samples of reservoir sediment, sediment extract, plant debris from banks and surrounding soil also supported geosmin production by S. albidoflavus. Both bank debris and exposed sediment developed earthy odours without inoculation. The structure of reservoir banks influenced the quantity of plant growth and accumulation of litter, and therefore also the potential for contamination of reservoir water by geosmin. The potential of these various sites of geosmin production to contaminate reservoir water is assessed.
A colorimetric enzyme assay using Escherichia coli to determine nutritionally available lysine in biological materials
Authors: TUFFNELL JANET M. , PAYNE J.W.
Published: March 2008

A novel bacterial method is described for determining nutritionally available lysine in protein foods with a lysine auxotroph of Escherichia coli (strain M2626). Lysine‐dependent synthesis of the induced enzyme bT‐galactosidase is determined by a colorimetric method. With this approach sensitivity is increased ca 100‐fold and assay time decreased to ca 2 h. The improved procedure was applied to the assay of lysine present as the free amino acid or in small peptides, and after enzymic pre‐digestion in vitro with a mixture of pronase and intestinal peptidases, to pure proteins and a variety of feed meals and rice cultivars. In addition, heat treatment of complex samples was shown to lower their content of available lysine, as judged by the decreased nutritional response of the E.coli strain.
Book Reviews
Authors: PATTERSON J.T.
Published: March 2008

Book reviewed in this article:

A MODERN INTRODUCTION TO FOOD MICROBIOLOGY (1983). R.G. Board. 236 pp. Oxford: Blackwell Scientific Publications. pD8.75.
The effect of ammonia treatment on the solubilization of straw and the growth of cellulolytic rumen bacteria
Authors: KOLANKAYA N. , STEWART C.S. , DUNCAN SYLVIA H. , CHENG K.‐J. , COSTERTON J.W.
Published: March 2008

Pre‐treatment of straw with anhydrous ammonia increased its susceptibility to solubilization by the predominant cellulolytic bacteria from the rumen, Bacteroides succinogenes, Ruminococcus albus and R. flavefaciens. Ammonia treatment also increased the production of microbial protein and fermentation products by all three species. Scanning electron microscope observations of straw during digestion suggested that the attack of straw by these bacteria was accompanied by the formation of substantial numbers of adherent microcolonies.
A note on antibiotic resistance in the bacterial flora of raw sewage and sewage‐polluted River Tigris in Mosul, Iraq
Authors: AL‐JEBOURI M.M.
Published: March 2008

Polluted water samples collected from the River Tigris in the vicinity of a raw sewage outfall were examined for the incidence of antibiotic resistance among coli‐form bacteria on three occasions during 1983. Eighty percent or more of the coli‐form bacteria were resistant to one or more antibiotics. At the same time, raw sewage samples were examined for the incidence of antibiotic‐resistant bacteria, and Escherchia coli, Pseudomonas spp. and Staphylococcus spp. were selected for sensitivity testing. Collectively, more than 90% of the 480 strains of the three organisms were resistant to one or more antibiotics. The minimal inhibitory concentration (MIC) of ampicillin for twenty‐nine strains including coliforms, E. coli, Klebsiella sp., Serratia sp., Ps. aeruginosa, Pseudomonas sp., Micrococcus sp., Staph. aureus, Streptococcus faecalis and Bacillus sp. from raw sewage and polluted River Tigris water was determined and that for Ps. aeruginosa was 250 μg/ml. The high incidence of antibiotic‐resistant bacteria in natural waters could be related to the widespread use of antibiotics in this locality.
A simple most probable number method for the enumeration of sulphate‐reducing bacteria in biocide containing waters
Authors: BATTERSBY N.S. , STEWART D.J. , SHARMA A.P.
Published: March 2008

A simple most probable number (MPN) method has been developed for the enumeration of sulphate‐reducing bacteria (SRB) in biocide‐containing waters. The medium used is based on source water, it contains no toxic thioglycollate and is resistant to oxidation through mishandling. Reduction is by a suspension of Pseudomonas putida which acts as a powerful adsorbent of biguanide, phenolic, quaternary ammonium compound, glutaraldehyde and isothiazolone biocides. Good recoveries of SRB type strains were obtained using this method and were comparable to other published techniques. Recovery of SRB in mixed culture was comparable to that using a standard laboratory technique.
A comparison of the ecology of Escherichia coli in the intestine of healthy unweaned pigs and pigs after weaning
Authors: HINTON M. , HAMPSON D.J. , HAMPSON ELISABETH , LINTON A.H.
Published: March 2008

A total of 51 clinically healthy pigs (14 unweaned and 37 weaned) from five litters, and aged 21 to 35 d, were studied. Escherichia coli isolates from the duodenum, jejunum, ileum, caecum and colon were differentiated on the basis of O‐serogroup, biotype and resistance pattern. The complexity of the flora was influenced considerably by the presence or absence of the enterotoxigenic serotype 0149: K91, K88a, o (Abbotstown strain). When it was absent the E. coli flora of both weaned and unweaned pigs was complex with up to 25 strains being identified. The majority of these E. coli strains identified in each pig were isolated from only one of the five intestinal sites sampled. On the other hand, when the enterotoxigenic strain was present (14 pigs) it tended to dominate the E. coli flora at all levels of the intestine and this dominance was reflected in a corresponding fall in the total number of E. coli strains isolated per pig.
A note on legionellas in whirlpools
Authors: GROOTHUIS D.G. , HAVELAAR A.H. , VEENENDAAL H.R.
Published: March 2008

Water samples from 52 whirlpools (jacuzzi), water temperature 35–40°C, and from 50 swimming pools, water temperature 8–30°C, were investigated for the presence of Legionella pneumophila. This was isolated from 11 of 28 whirlpools with free available chlorine less than 0.3 mg/1. No legionellas were detected in 23 whirlpools with free available chlorine over 0.3 mg/l. Legionella pneumophila was found in two swimming pools. The results indicate that 0.3 mg/l of free available chlorine is sufficient to eliminate legionellas from whirlpools.
Production and storage of Rhizobium leguminosarum cell concentrates for use as inoculants
Authors: MEADE J. , HIGGINS P. , O'GARA F.
Published: March 2008

Recovery of Rhizobium leguminosarum cells by centrifugation after growth in an industrial fermenter was 100‐fold higher when cells were grown on yeast extract (5 g/1) as sole source of carbon and nitrogen when compared with the yields recovered when cells were grown in standard mannitol‐yeast extract medium. Methods of storing concentrated suspensions of R. leguminosarum were investigated. Freeze‐drying caused a marked decrease in viable cell numbers. Viable cell numbers of bacterial concentrates stored in peat decreased steadily from 1011‐1012 cfu/g to 109 cfu/g or less during 26 weeks storage at room temperature or at 4°C. Cell concentrates stored in 40% glycerol at — 20°C maintained viable numbers higher than 1011 cfu/ml during a 76 week storage period.
A note on the use of dextran in blood cultures monitored by conductance methods
Authors: CURTIS G.D.W. , THOMAS C.D. , JOHNSTON H.H.
Published: March 2008

The incorporation of dextran into broth for the detection of bacteraemia by conductance monitoring is recommended to eliminate the effect of sedimenting blood cells which may mask early signals from bacteria. Broth containing ten times the recommended concentration of dextran was tested with a wide range of bacteria without demonstrating any reduction in growth or rate of change of conductance.
Studies on the stability of solvent production by Clostridium acetobutylicum in continuous culture
Authors: STEPHENS GILLIAN M. , HOLT R.A. , GOTTSCHAL J.C. , MORRIS J.G.
Published: March 2008

Various methods of continuous flow culture of Clostridium acetobutylicum NCIB 8052 were investigated, with the aim of obtaining prolonged production of acetone and butanol. In ammonia‐limited chemostat culture, maximal concentrations of solvents were obtained at pH 5–5 at a relatively high biomass concentration of 1.3–2.0 g/1 dry weight maintained at a dilution rate of 0.06/h. Similar dependence of solvent production on the sustenance of a relatively high cell density was observed in magnesium‐ or phosphate‐limited chemostat cultures. Solvent production was always transient, however, with a shift to production of only acetic and butyric acids being observed after 4–16 volume changes. Longer term solvent production was obtainable under conditions of glucose limitation but the solvent yield was low. Cultivation in a pH‐auxostat permitted solvent production in reasonably high yield over at least 70 volume changes with no signs of culture degeneration. Although none of the continuous flow cultures achieved a true steady state, we conclude that turbidostat or pH‐auxostat culture are the methods of choice for continuous solvent production by Cl. acetobutylicum NCIB 8052.
A note on the screening of dried shrimps, shrimp paste and raw groundnut kernels for aflatoxin‐producing Aspergillus flavus
Authors: Sim T.S. , Teo Theresa , Sim T.F.
Published: March 2008

Sim, T.S., Teo, Theresa & Sim, T.F. 1985. A note on the screening of dried shrimps, shrimp paste and raw groundnut kernels for aflatoxin‐producing Aspergillus flavus. Journal of Applied Bacteriology 59, 29–34.

All of 33 samples of dried shrimps, shrimp paste, peanut butter and raw groundnut kernels were contaminated with fungi. Aspergillus and Penicillium spp. were the predominant types in dried shrimps and raw groundnut kernels but no Aspergillus spp. were present in peanut butter or shrimp paste samples. Among 81 Aspergillus isolates obtained from dried shrimps and raw groundnut kernels, 10 were A. flavus/ A. parasiticus, of which five were potential aflatoxin‐producing A. flavus strains. No aflatoxins were detected in the food samples although some were visibly mouldy and some had high mould counts. The occurrence of aflatoxin‐producing strains of A. flavus in dried shrimps and raw groundnut kernels warrants further investigation of these foods and their products as potentially significant sources of aflatoxins.
Collaborative study on the isolation of salmonella from artificially contaminated milk powder
Authors: Beckers H.J. , Leusden F.M. Van , Roberts D. , Pietzsch O. , Price T.H. , Schothorst M. Van , Tips P.O. , Vassiliadis P. , Kampelmacher E.H.
Published: March 2008

Beckers, H.J., van Leusden, F.M., Roberts, D., Pietzsch, O., Price, T.H., van Schothorst, M., Tips, P.D., Vassiliadis, P. & Kampelmacher, E.M. 1985. Collaborative study on the isolation of salmonella from artificially contaminated milk powder. Journal of Applied Bacteriology59, 35–40.

The suitability of artificially contaminated milk powder as a substrate for salmonella reference samples and its stability under different storage conditions were studied. The need for a reconstitution step in the standard isolation method for salmonellas from milk powders was also investigated. When milk powder was examined in this way with a reconstitution step, differences in laboratory methods and/or storage times had no significant effect on the results after storage at 4d̀C. With powder stored at room temperature there was a systematic decrease in the number of samples positive as the storage time increased. It is concluded therefore that milk powder contaminated with salmonellas should be stored at 4d̀C. Examination of such milk powder with a reconstitution step yielded better results than without it and this step is therefore necessary for improving the reproducibility of the method. No significant differences were encountered between the standard isolation method and that used in the authors' laboratories. The results of this study indicate that milk powder is suitable as basic material for reference samples and that a reconstitution step should be included in the standard salmonella isolation procedure.
A note on the increased permeability of opsonized luminous bacteria
Authors: Barak Mira , Merzbach D. , Ulitzur S.
Published: March 2008

Barak, M., Merzbach D. & Ulitzur, S. 1985. A note on the increased permeability of opsonized luminous bacteria. Journal of Applied Bacteriology59, 57–59.

Opsonization of a dark variant of the luminous bacterium Photobacterium leiog‐nathi by pooled human serum caused an increase in the permeability of the organism to actinomycin D, as judged by the inhibition of the proflavin‐induced synthesis of its luminescence system.
Lysis of Phormidium luridum by Myxococcus fulvus in continuous flow cultures
Authors: Daft M.J. , Burnham J.C. , Yamamoto Yoko
Published: March 2008

Daft, M.J., Burnham, J.C. & Yamamoto, Y. 1985. Lysis of Phormidium luridum by Myxococcus fulvus in continuous flow cultures. Journal of Applied Bacteriology59, 73–80.

In two chemostat systems Myxococcus fulvus (strain BGO2) adhered to the glass walls of the growth vessel and on glass beads contained in a vertical glass column. The bacterium produced long colonial strands that extended towards the centre of the vessel. Both systems allowed measurement of lytic enzyme production and cyanobacterial predatory efficiency. Lysozyme activity produced by the myxococci was dependent on the concentration of the tryptone and the flow rate of the medium. Continuous lysis of Phormidium luridum occurred in both methods of culture in the presence of M. fulvus (strain BGO2). The results suggest that the adhesive characteristics of this bacterium prevent the achievement of steady state kinetics in either saprophytic or parasitic modes of growth. M. fulvus, with its various morphological growth forms and effectiveness in lysing cyanobacteria, is considered to be a potential control agent of cyanobacteria.
Cellulolytic and dextranolytic Gram‐negative bacteria: revival of the genusCellvibrio
Authors: Blackall Linda L. , Hayward A.C. , Sly L.I.
Published: March 2008

Blackall, LindaL., Hayward, A.C. & Sly, L.I. 1985. Cellulolytic and dextranolytic Gram‐negative bacteria: revival of the genusCellvibrio. Journal of Applied Bacteriology59, 81–97.

Nine bacterial strains were isolated from rhizosphere soils by enrichment in a defined mineral salts medium containing either cellulose or dextran as the sole carbon source. These and 17 reference strains, including representatives of two species of the invalid genusCellvibrio, were characterized on morphological, biochemical and physiological properties. Numerical analyses were performed on the results using two different measures of similarity and methods of clustering. Eight of the nine isolates, three unnamed reference strains and the strains ofCellvibrioshowed a high level of similarity and comprised a single cluster in both methods of analysis. The salient properties of strains in this cluster were: Gram‐negative, aerobic, slender rods, some having a slightly curved axis; mixed flagellation; oxida‐tive metabolism of glucose; extensive hydrolytic ability on complex polysaccharides; production of curdlan polysaccharide on glucose. Revival of the genusCellvibrio(Winogradsky 1929) gen. nov., with an amended description and a new type speciesCellvibrio mixtussp. nov. is proposed.
Effects of aqueous and alcoholic povidone‐iodine on spores of Bacillus subtilis
Authors: Gorman S.P. , Scott E.M. , Hutchinson E.P.
Published: March 2008

Gorman, S.P., Scott, E.M. & Hutchinson, E.P. 1985. Effects of aqueous and alcoholic povidone‐iodine on spores of Bacillus subtilis. Journal of Applied Bacteriology, 59, 99–105.

Spores of Bacillus subtilis NCTC 10073 were examined for susceptibility to two proprietary brands of povidone‐iodine: an aqueous solution, Betadine and an alcoholic solution, Videne. Spores were converted to ion‐exchange (Ca, H) and coat‐defective (SLS‐, UME‐, UMS‐, UDT‐ and UDS‐treated) forms. The resistance of these to povidone‐iodine was compared and related to uptake. Effects on spore protoplasts and cortex in relation to hexosamine release were also examined. The degree of spore penetration and site of action of povidone‐iodine is discussed.
A note on the occurrence of Leuconostoc oenos as a spoilage organism in canned mango juice
Authors: Ethiraj S. , Suresh E.R.
Published: March 2008

Ethiraj, S. & Suresh, E.R. 1985. A note on the occurrence of Leuconostoc oenos as a spoilage organism in canned mango juice. Journal of Applied ‐Bacteriology59, 239–242.

A strain of Leuconostoc oenos was isolated from a blown can of mango juice. Various tests to identify and characterize the bacterium suggested that it could be a strain of L. oenos. This is the first report of L. oenos as a spoilage organism in fruit products other than wine.
Variation within Pseudomonas syringae pv. philadelphi, the cause of a leaf spot of Philadelphus spp.
Authors: Roberts S. J.
Published: March 2008

Roberts, S.J. 1985. Variation within Pseudomonas syringae pv. philadelphi, the cause of a leaf spot of Philadelphius spp. Journal of Applied Bacteriology59, 283–290

In pathogenicity tests on Philadelphus and other plant species, belonging to ten genera in seven families, isolates of Pseudomonas syringae from leaf spots on Philadelphus spp. in England did not produce symptoms on any plants other than Philadelphus. It is therefore proposed that these isolates should be designated a distinct pathovar of Ps. syringae with the name Pseudomonas syringae pv. philadelphi. Isolates of this new pathovar varied in their reactions to 6 of 57 biochemical tests. In phage typing tests isolates also varied in their sensitivity to five of seven bacteriophage strains. Four of the six biochemical tests (aesculin hydrolysis, utilization of DL‐homoserine L‐leucine and sorbitol) and all five of the phages (P11, Pls, P2, A15, and A26) were used to separate the isolates into seven groups. These groups had some relation to their geographical origin, species of Philadelphus from which they were originally isolated, and relative virulence on P. coronarius and P. x purpureo‐maculatus. They may represent ecotypes of this new pathovar.
The effect of nisin‐sodium chloride interactions on the outgrowth of Bacillus licheniformis spores
Authors: Bell R.G. , Lacy Karen M. De
Published: March 2008

The effect of salt (NaCl) on the efficacy of nisin in preventing outgrowth of Bacillus licheniformis spores was determined in Plate Count Agar (PCA). An equivalent liquid medium was used for heat activation. Nisin and salt were added to the heat‐activation medium, the PCA, or both. The spores were extremely sensitive to nisin; outgrowth were completely inhibited in salt‐free media when 10 iu/ml of nisin was present in both the heat‐activation and the growth media or when 100 iu/ml nisin was present in either the heat‐activation and the growth medium. In media supplemented with 1% salt, outgrowth occurred from 1% of spores exposed to 100 iu/ml nisin in either the heat‐activation or the growth medium. A 3% salt supplement was necessary before detectable outgrowth occurred when both the heat‐activation and the growth media contained 100 iu/ml nisin. Salt appears to antagonize the sporicidal action of nisin by interfering with nisin adsorption onto the spore.
A note on estimation of food spoilage yeasts by measurement of adenosine triphosphate (ATP) after growth at various temperatures
Authors: Patel P.D. , Williams A.P.
Published: March 2008

The growth at 4d̀, 10d̀ and 15d̀C of six psychrotrophic yeasts isolated from foods was compared using total viable counts and ATP measurement. A linear relationship (r > 0.97) was obtained between log10 (number of viable yeasts) and log10 (ATP content) of cultures grown at these temperatures. This relationship was not temperature‐dependent. The results are discussed and their significance for the rapid estimation of yeasts in foods is considered.
Classification of some lactic acid bacteria from vacuum‐packed meats by direct probe mass spectrometry
Authors: Shaw B.G. , Puckey D.J. , Macfie H.J.H. , Bolt Sarah J.
Published: March 2008

The technique of direct probe mass spectrometry (DPMS) has been applied to the classification of 40 strains of lactic acid bacteria from refrigerated vacuum‐packed beef, pork, lamb and bacon. Relationships between strains were examined by multi‐variate statistical techniques using sets of ions selected for reproducibility and sample discrimination. Five groups were distinguished which corresponded closely to those detected in a previous numerical taxonomic study. Two groups contained all 12 representatives of a cluster of unidentifiable non‐aciduric streptobacteria whose sub‐division is supported by other taxonomic evidence. All twenty‐one strains from a cluster of aciduric streptobacteria provisionally identified with Lacto‐bacillus sake were contained in two further groups. The sub‐division of these acid‐uric strains revealed by DPMS has not been verified by other techniques and requires further investigation. The fifth group contained Leuconostoc strains. The study demonstrates the value of DPMS in confirming and clarifying classification schemes obtained by conventional methods.
A note on the use of Rappaport‐Vassiliadis medium (RIO/RV) for the isolation of salmonellas from sewage and sewage sludges
Authors: Watson D.C.
Published: March 2008

The use of a modified Rappaport broth for the selective enrichment of salmonellas in sewage sludge is described. Comparative trials were carried out using Muller Kauffman—Tetrathionate (MKT) broth and Rappaport‐Vassiliadis (R10/RV) medium for selective enrichment. Results have indicated that R10/RV broth is more selective and is to be preferred for routine monitoring.
Sensitivity of Saccharomyces cerevisiae vegetative cells and spores to antimicrobial compounds
Authors: Romano Patrizia , Suzzi G.
Published: March 2008

The sensitivity of Saccharomyces cerevisiae spores and vegetative cells to various antimicrobial compounds was compared. Sulphur dioxide, benzoic acid, potassium sorbate, salicylic acid, nystatin, actidione and pimaricin were tested. Generally, the Saccharomyces spores were more resistant than the corresponding vegetative cells. It was also observed that this greater resistance shown by the spores varied with the antimicrobial compound used. Only potassium sorbate was not selective and killed both vegetative cells and spores at about the same rate.
The influence of milk and milk components on the attachment of bacteria to farm dairy equipment surfaces
Authors: Speers J.G.S. , Gilmour A.
Published: March 2008

Glass, rubber and stainless steel surfaces were exposed to various types of bacteria in the presence of milk and a number of milk components under both static and agitated incubation conditions. Numbers of bacteria attaching were enumerated by epifluorescence microscopy. Results were affected by the different bacterial types, the nature of the attachment surface and the substances in which the bacteria were suspended with a Moraxella‐like species, stainless steel and lactose and non‐casein protein solutions respectively resulting in greatest numbers of cells attaching. Agitation had no marked influence on attachment.
A sensitive enzymic assay for benzylpenicillin
Authors: Baker W.L.
Published: March 2008

A method has been developed for the determination of sodium benzylpenicillin concentrations in the range 3·3–33 μg/ml. 6‐Aminopenicillanic acid is released from the benzylpenicillin by the action of the enzyme penicillin acylase and is estimated from its reaction with fluorescamine at pH 4.7‐Aminocephalosporanic acid shows a similar trend to 6‐aminopenicillanic acid in its reaction at pH 4. The open β‐lactam ring form of each compound shows little fluorescence with fluorescamine at pH but shows strong fluorescence in the pH range 7–9. 6‐Aminopenicillanic acid and its open β‐lactam ring form give different fluorescent responses to increasing volumes of a solution of the fluorigenic agent at pH 7·8. This effect can be used to estimate concentrations in a mixture of the two components providing other amino material is absent.
A note on the isolation of Staphylococcus aureus from raw minced meat
Authors: Isigidi B.K. , Devriese L.A. , Hoof J. Van
Published: March 2008

Conventional Baird‐Parker medium (BP) and three modified BP‐type media were tested for their suitability to detect and to enumerate Staphylococcus aureus in raw minced meat. BP with pig plasma gave the most rapid results without the need for extensive confirmatory tests. A method which combined a liquid modification of BP medium with BP agar supplemented with acriflavine, polymyxin and sulphamezathine, was cheaper, more sensitive, and did not necessitate additional identification. Conventional BP incubated at 37d̀ and 43d̀C yielded less satisfactory results.
Determination of the heat resistance of spores using a solid heating block system
Authors: Mallidis C.G. , Scholefield J.
Published: March 2008

A simple and accurate technique for the determination of the heat resistance of spores is described. The technique combines a modified capillary tube method with a solid heating block. The come‐up time of spore suspensions was found to be short and simple and accurate technique is suggested for the correction of the come‐up times. Experimental results are presented for the destruction of spores of Bacillus stearothermophilus at 120d̀ which indicates the accuracy and reproducibility of the new method.
Standardization of salt aggregation test for reproducible determination of cell‐surface hydrophobicity with special reference to Staphylococcus species
Authors: Rozoonyi F. , Szitha Katalin R. , Hjertén S. , Wadström T.
Published: March 2008

The laboratory conditions for reproducible routine determination of staphylococcal cell‐surface hydrophobicity by the salt aggregation test were standardized. Fresh bacterial suspensions standardized to 5 times 109 cfu/ml gave the most reproducible results with both Staphylococcus aureus and coagulase‐negative staphylococci. For relatively hydrophobic strains a 5‐min reading time was necessary to detect bacterial aggregation in ammonium sulphate solutions ranging from 0.1 M to 1.5 M, pH 6.8. A × 10 hand lens facilitated reading aggregations. Overnight storage of bacterial suspensions at 20d̀C reduced cell‐surface hydrophobicity of all species, while storage at 4d̀C reduced the hydrophobic nature of Staph. aureus strains. The hydrophobicity of coagulase‐negative staphylococci rarely changed at 4d̀C. A 10‐fold dilution of fresh, standardized bacterial suspensions made it impossible to detect bacterial aggregation in ammonium sulphate solutions even with a hand lens. Under standardized conditions three types of staphylococcal cell aggregations were observed. The first looked like the slide agglutination for O antigens of Enterobacteriaceae, the second resembled H‐agglutination, while the third had a filamentous appearance. These patterns indicated that more than one component might contribute to cell‐surface hydrophobicity of both Staph. aureus and coagulase‐negative staphylococci, or the same component might have different position on the cell surface.
Studies on the preservation and bottling of oyokpo—a Nigerian beer from millet (Pennisetum typhoideum)
Authors: Iwuagwu Y. O. U. , Izuagbe Y.S.
Published: March 2008

Better preservation of oyokpo beer was obtained by treating it with sodium benzoate alone than by sodium metabisulphite, propionic acid, pasteurization or combinations of chemical preservatives and pasteurization.
Reference material for the evaluation of a standard method for the detection of salmonellas in foods and feeding stuffs
Authors: Beckers H. J. , van Leusden F.M. , Meijssen M. J. M. , Kampelmacher E.H.
Published: March 2008

To evaluate a standard salmonella isolation method a reference material consisting of 0.2 g spray‐dried milk inoculated with Salmonella typhimurium and contained in gelatin capsules was prepared. The organisms were distributed homogeneously between capsules, and their numbers were stable for 120 d when the capsules were stored in dry conditions at 4d̀C. Addition of these capsules with or without food samples to pre‐enrichment broth gave low and reproducible levels of Salm. typhimurium contamination without altering the pre‐enrichment and without influencing the other bacterial flora present. As a result of an interlaboratory trial, the reference material indicated that the food and/or its competitive flora may have a negative influence on the detection of salmonellas.