bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibrio anguillarum: Influence of temperature, pH, NaCl concentration and incubation time on growth
Authors: Larsen J.L.
Published: March 2008

An analysis of the effect of growth conditions on the growth (O.D. values) of five Vibrio anguillarum strains showed that the optima were as follows: pH 7, temperature 25°C, NaCl concentration 2%, and O.D. estimates increased with the incubation time. The independent parameters, as well as their interactions significantly influenced the growth of Vibrio anguillarum (P0<0001). Only the strain‐salinity interaction was not always statistically significant. A restriction of the parameters to a level relevant for Danish marine recipients showed that pH and NaCl concentration (salinity) might be of minor importance while the temperature was always of high significance. The possible impact of these observations on local conditions is discussed.
Allogenic succession of marine bacterial communities in response to pharmaceutical waste
Authors: Grimes D.J. , Singleton F.L. , Colwell R.R.
Published: March 2008

Vibrio spp. predominated in the culturable bacterial community of surface waters of the Puerto Rico Trench at the site of disposal for nearly ten years of pharmaceutical wastes. In this area and surrounding waters as far as 1000 km north of the dumpsite and south into the Caribbean Sea, Vibrio spp. comprised up to 100% of the culturable bacteria, with Acinetobacter spp. being the second most prevalent group. Pseudomonas spp., reported to be common in these waters a decade earlier, were virtually absent from all samples examined during a three year study involving 9 cruises. Staphylococcus spp. were also found in water samples collected within the dumpsite. Using cultures isolated from surface water samples collected at the dumpsite, laboratory experiments confirmed that pharmaceutical waste can enrich for Vibrio spp., in preference to Pseudomonas spp., with growth of the strains proportional to the amount of waste added.
Conductance measurements of the lag phase of injured Salmonella typhimurium
Authors: Mackey B.M. , Derrick Christine M.
Published: March 2008

The duration of the lag phase of Salmonella typhimurium injured by heating, freezing, acidification or drying was measured using the ‘Malthus’ conductance meter. Results confirmed those previously obtained by viable counting and additionally, revealed the very wide variation in lag between and within populations and the extreme length of lag that can occur in some severely injured cells. In an extreme example, the measured lag times of low numbers of bacteria taken from the same heat‐injured population ranged from 16 h to 70 h. The implications for the detection of injured micro‐organisms in food are discussed.
Effect of the fungicide captafol on the survival and symbiotic properties of Rhizobium trifolii
Authors: Ruiz‐Sainz J.E. , Beringer J.E. , Gutierrez‐Navarro A.M.
Published: March 2008

The fungicide captafol is toxic to Rhizobium trifolii at concentrations greater than 75 μg/ml, and at lower concentrations it affects growth adversely. Captafol‐resistant mutants were isolated and all were found to have lost the same plasmid and the ability to nodulate clovers. Nodulation plasmids transferred from a R. leguminosarum or R. trifolii donor to the resistant mutants conferred the ability to nodulate peas and clover plants, respectively. The rhizobia remained resistant to captafol indicating that the genetic alteration leading to captafol resistance was not necessarily detrimental to the ability of the bacteria to form nitrogen fixing nodules. These results indicate that captafol may act as a plasmid‐curing agent in R. trifolii.
The microbiology of stockfish during the drying process
Authors: Valdimarsson G. , GuđbjöUrnsd'Attir B.
Published: March 2008

Stockfish is made by drying various species of fish in the open air to a final water content of 17–18% (w/w). By this treatment the fish acquires a very characteristic flavour. A study was made of the microbiology of blue ling (Molva dypterygia dypterygia) during this process. Aerobic plate counts at 22°C in the flesh of the fish reached a maximum of 4.1 times 107/g dry weight, after drying for 30 days. Analyses of the aerobic/facultatively anaerobic bacterial flora in the flesh showed initially a dominance of Moraxella and Acinetobacter‐like spp. As the drying progressed a Gram positive, catalase negative flora appeared, increasing its proportion to 77% of the bacterial content of the fish. Representative strains of these bacteria were identified as Lactobacillus plantarum.
Numerical taxonomy of cholesterol‐degrading soil bacteria
Authors: Ferreira N.P. , Tracey R.P.
Published: March 2008

Eighty‐four nocardioform bacteria freshly isolated from soil samples have been compared with 28 marker cultures in a numerical taxonomic study in which 114 unit characters were determined. The strains were recovered in seven major clusters and two minor clusters. Nine strains could not be assigned to any one of the clusters. Six of the major clusters could be identified with named cultures or type strains of Rhodococcus erythropolis, R. rubropertinctus, and R. terrae, R. equi, R. rhodocrous, R. coprophilus and Mycobacterium fortuitum. Three of the local isolates were recovered in a minor cluster related to the M. fortuitum cluster. Three type strains and two marker cultures of the genus Nocardia were grouped in a minor cluster. The remaining major cluster consisted of 16 strains that were identified as rhodococcal strains. However, these 16 strains could not be equated with any of the established Rhodococcus species. It is therefore proposed that these strains be considered a new species within the genus Rhodococcus for which the specific name Rhodococcus australis is proposed. A description of the new species is given.
The influence of ionic gradients on flocculation of Brevibacterium sp.
Authors: McLoughlin A.J. , Vallom J.K.
Published: March 2008

The effects of inhibition of various physiological processes were evaluated with respect to flocculation of Brevibacterium sp. and it was shown that those influencing energy levels improved flocculation. Ionophores, valinomycin and gramicidin, brought about the greatest improvement in both the rate and degree. Valinomycin‐induced flocculation was influenced by the concentration of external potassium. These results demonstrate that intracellular ionic gradients exerted an influence on flocculation; dissipation of H+ or K+ gradients induced a higher level of flocculation.
A note on xenogeneic transfusions of macrophages in experimental septicaemia
Authors: Fakhri O. , Al‐Waili N. , Al‐Azawi H. , Makkiya A.
Published: March 2008

Human peritoneal macrophages (Mφ) were given intravenously to normal rabbits and rabbits with Escherichia coli septicaemia. No harmful effects were observed during a period of three months following macrophage transfusions and the septicaemia was eradicated in four of five animals. Thus xenogeneic Mφ transfusion is feasible and can combat serious bacterial infections.
Identification of streptococci in a medical laboratory
Authors: Colman G. , Ball Lyn C.
Published: March 2008

A total of 965 cultures of streptococci received at a reference unit for identification were examined with API‐20 Strep kits and also by established methods. The API method, although it needed to be supplemented with additional tests, largely overcame the difficulty that pyogenic streptococci are usually identified by their serological reactions and that biochemical tests are used for the identification of the other streptococci. Representatives of at least 24 established or possible species were identified.
Nitrogen fixation by cellulolytic communities at aerobic‐anaerobic interfaces in straw
Authors: Harper S. H. T. , Lynch J.M.
Published: March 2008

Microbial communities involved in both cellulolysis and nitrogen fixation were isolated from decomposing straw. Cellulolytic activity appeared restricted to fungal isolates, predominantly species of Penicillium and Fusarium, growing in the presence of oxygen. Bacteria isolated under anaerobic conditions on nitrogen‐free media were identified exclusively as Clostridium butyricum. Enterobacters isolated on media containing fixed nitrogen, particularly Enterobacter cloacae, might also be involved in nitrogen fixation when growing under conditions of restricted aeration. Anaerobic or facultative anaerobic nitrogen‐fixing bacteria are thought to be sustained by the products of cellulolytic enzymes from aerobic fungi.
Scanning electron microscopy of dairy equipment surfaces contaminated by two milk‐borne micro‐organisms
Authors: Speers J.G.S. , Gilmour A. , Fraser T.W. , Mccall R.D.
Published: March 2008

Ethanol dehydration followed by argon replacement induced drying (ARID) was found to be a suitable method for the preparation of glass, stainless steel and rubber surfaces which had been in contact with inoculated milk and which were to be examined using scanning electron microscopy (SEM). This technique was used to examine samples of all three materials which had been subjected to both single and repeated inoculation with whole milk containing a Pseudomonas sp. or a Micrococcus sp. and incubated for various periods. Some samples were also prepared for SEM using a cryofixation technique. The Pseudomonas sp. was found to proliferate on glass and stainless steel surfaces but not on rubber. Due to the clumping tendency of the Micrococcus sp. proliferation of this organism was more difficult to assess accurately. In general there was no difference in results obtained between single and repeated inoculation. Various factors which may have aided attachment of micro‐organisms to surfaces were identified viz., surface channels present in stainless steel, milk deposits and the production of extracellular material. The value of using both the cryofixation and chemical preparatory techniques for the identification of artifacts is discussed.
A note on the effect of dilution and temperature on the bactericidal activity of potassium sorbate
Authors: Lusher P. , Denyer S.P. , Hugo W.B.
Published: March 2008

The effect of dilution and temperature on the antibacterial properties of potassium sorbate was determined. The time taken to kill a standard inoculum of Escherichia coli was increased considerably after either dilution of the preservative or lowering of the temperature. The value for the concentration exponent, η, was approximately 3 and that for the temperature coefficient, Q10, was 2.3.
The influence of incubation temperature and pH on the antimicrobial properties of hen egg albumen
Authors: Tranter H.S. , Board R.G.
Published: March 2008

Tranter H.S. & Board, R.G. 1984. The influence of incubation temperature and pH on the antimicrobial properties of hen egg albumen. Journal of Applied Bacteriology56, 53–6.

Gram positive bacteria, including lysozyme‐resistant strains, and yeasts were killed in hen egg albumen with or without iron at 30 of 39.5.dGC. The albumen was more toxic at 39.5.dGC than at 30d̀C for Gram negative bacteria. With the exceptions of Pseudomonas fluorescens, Acinetobacter sp. and Proteus vulgaris, iron caused the growth of Gram negative bacteria or protected them from being killed in hen albumen at 39.5.dGC. At this temperature, however, maximal growth of and glucose utilization by Escherichia coli C20 only occurred in albumen supplemented with growth factors, trace metals, additional nitrogen and sufficient iron to quench ovotransferrin. The bactericidal properties of albumen could be negated by changing its pH from 90 or above to 7.5 or below. At 39.5d̀C, enterochelin allowed growth of E. coli in albumen at pH 7.9, but not at 9.4, whereas iron allowed growth at both pH values.
Microbial metabolism of 1,2‐propanediol studied by the Rumen Simulation Technique (Rusitec)
Authors: Czerkawski J.W. , Piatkova M. , Breckenridge G.
Published: March 2008

Czerkawski J.W., Piatkova M. & Breckenridge, G. 1984. Microbial metabolism of 1,2‐propanediol studied by the Rumen. Simulation Technique (Rusitec). Journal of Applied Bacteriology, 56, 81–94.

A series of experiments with the Rumen Simulation Technique (Rusitec) showed that 1,2‐propanediol was metabolized efficiently by rumen micro‐organisms and that the main end‐products of fermentation were propionic and 2‐methylbutyric acids. ‘Propionaldehyde and n‐propanol were also formed as intermediate compounds.’ The effect of the diol on digestion of the basal diet appeared to be small with concentrate, or when the roughage was supplemented with additional nitrogen (urea). The decrease in the output of acetic and butyric acids was consistent with utilization of C2 units for synthesis of 2‐methylbutyric acid. The fermentation of 1,2‐propanediol resulted in little or no increase in the output of additional microbial matter. The distribution of radioactivity from [1‐14C] 1,2‐propanediol confirmed that propionaldehyde and n‐propanol were the primary products of metabolism of the diol and that the end‐products were propionic and 2‐methylbutyric acids, with very little labelling of microbial matter. Between 2% and 3% of radioactivity was found in gases and surprisingly the specific radioactivity of methane was higher than that of carbon dioxide, particularly during the initial stages of incubation. Possible pathways in the degradation of 1,2‐propanediol by rumen micro‐organisms are suggested and discussed in relation to similar reactions established in other systems.
Interaction of the Bacillus subtilis spore protoplast, cortex, ion‐exchange and coatless forms with glutaraldehyde
Authors: Gorman S.P. , Scott E.M. , Hutchinson E.P.
Published: March 2008

Gorman, S.P. Scott, E.M. Hutchinson, E.P. 1984. Interaction of the Bacillus subtilis spore protoplast, cortex, ion‐exchange and coatless forms with glutaraldehyde. Journal of Applied Bacteriology56, 95–102.

Bacillus subtilis spores with altered ionic content were tested for their susceptibility to lysis with lysozyme or sodium nitrite following treatment with glutaraldehyde. The Ca‐form was more sensitive to glutaraldehyde (pH 4.0.and pH 7.9) than the untreated or H‐form. Removal of spore coat dramatically increased sensitivity of the spore to glutaraldehyde. Pretreatment of spores, the coats of which had been extensively removed, with glutaraldehyde (pH 7.9) reduced the rate of lysis by lysozyme and by sodium nitrite, whereas glutaraldehyde at pH 4.0.had little effect. Glutaraldehyde pretreatment (pH 4.0 and pH 7.9) reduced the amount of hexosamine released by lysozyme but not by nitrite from isolated cortical fragments. Spore protoplasts were more susceptible to 0.01% (w/v) glutaraldehyde at pH 4.0 and isolated spore coats adsorbed alkaline glutaraldehyde more rapidly. These results are discussed in terms of a possible mode of action of glutaraldehyde on the bacterial spore.
Identification of coagulase‐negative staphylococci from farm animals
Authors: DEVRIESE L.A. , SCHLEIFER K.H. , ADEGOKE G.O.
Published: March 2008

The species identity of 661 strains of coagulase‐negative staphylococci isolated from the skin and nares of cattle, pigs, poultry, goats and sheep was determined. They belonged either to the novobiocin‐sensitive species Staphylococcus hyicus, Staph. simulans, Staph. epidermidis, Staph. haemolyticus and Staph. warneri or to the novobiocin‐resistant species Staph. sciuri, Staph. lentus, Staph. xylosus, Staph. cohnii. Staph. saprophyticus and Staph. gallinarum; twenty‐one strains remained unidentified. The staphylococcal flora of the farm animals studied differed markedly from that associated with man; several species which do not occur in man were isolated and novobiocin‐resistant strains, which occur infrequently in man, were present in large numbers in animals. Two simplified schemes for the identification of staphylococci from farm animals and man are presented.
A note on the effect of different storage procedures on the ability of Preston medium to recover campylobacters
Authors: FRICKER C.R.
Published: March 2008

The effect of different storage procedures on the ability of Preston medium to recover campylobacters was investigated. Freshly poured media was shown to recover more campylobacters than media stored under aerobic or anaerobic conditions at room temperature or at 4dEC. The growth of Campylobacter laridis was greatly reduced by storage of media and although most strains of C. jejuni and C. coli were not markedly affected, the growth of one strain of C. jejuni was considerably reduced. It is recommended that freshly prepared media be used whenever possible, but if storage is necessary, then plates should be held at 4dEC, preferably under anaerobic conditions. These precautions may not be necessary for workers interested solely in C. jejuni or C. coli, but are essential for the optimum isolation of C. laridis.
The planktonic and benthic bacterial populations of Lough Neagh
Authors: QUINN J.P. , GILLAN M.B. , MCGROGAN H.
Published: March 2008

The planktonic and benthic bacterial populations of Lough Neagh, Northern Ireland, were studied over a one‐year period. Direct counts of bacteria in the water column averaged 6 times 107/ml with limited spatial or temporal variation; viable counts, however, showed a pronounced late spring maximum of 1.7 times 106/ml and were consistently higher at a littoral sampling station. Direct counts of bacteria in the profundal sediments averaged 8 times 109/ml whilst viable benthic counts rose steeply during spring to reach a June maximum of 1 times 108/ml. Direct: viable count ratios were much greater in the more sandy littoral zone. The predominant benthic isolate was an Aeromonas sp. which was also common in samples from the water column. These results confirm the eutrophic status of Lough Neagh indicated by other biological and chemical surveys.
A note on nutritional influence on extracellular protease synthesis in Aeromonas hydrophila
Authors: PANSARE A. C. , VENUGOPAL V. , LEWIS N.F.
Published: March 2008

Several individual amino acids served as the sole nitrogen source for growth and extracellular protease synthesis by cells of Aeromonas hydrophila. In the presence of urea, ammonium compounds and glycine, enzyme production was severely repressed although cell growth was only moderately affected.
A note on the efficiency of stomaching for the quantitative removal of epiphytic bacteria from submerged aquatic plants
Authors: FRY J.C. , GOULDER R. , RIMES CARRIE A.
Published: March 2008

The effect of stomaching time on release of epiphytic bacteria from two species of submerged macrophytes was investigated, and the proportion of total epiphytes released from three species by stomaching was determined. A duration of 5 min was found to be an adequate stomaching time; the proportion released (mean ca 0.4) varied considerably between sites and sampling occasions.
The ecology of Escherichia coli in calves reared as dairy‐cow replacements
Authors: HINTON M. , LINTON A.M. , HEDGES A.J.
Published: March 2008

A continual turn‐over in the strains forming the majority of faecal Escherichia coli flora was demonstrated in 16 calves reared as dairy cow replacements. The incidence of antibiotic resistance among isolates, as measured by an Antibiotic Resistance Index (ARI), changed markedly with the age of the calf. The value was low initially, when the calves were 1–2 days old and housed with adult animals. It then rose rapidly during the first week after the animals had been weaned and moved into nursery pens. This change in ARI was associated with the isolation of strains resistant to four or five of the six drugs included in the sensitivity test. The ARI then fell from the third week to low levels by the time that the calves were five months of age. This fall was due to the isolation of an increasing proportion of sensitive E. coli strains. These differed from the sensitive strains which had colonized the calves in the early days of life so demonstrating that the change was not due to the reemergence of strains identified several weeks previously. The source of E. coli strains was presumed to be the calfs' environment but further investigations are required to prove this conclusively.
Biological indicators for low temperature steam formaldehyde sterilization: effect of defined media on sporulation, germination index and moist heat resistance at 110dEC of Bacillus strains
Authors: HOXEY E.V. , SOPER C.J. , DAVIES D.J.G.
Published: March 2008

Choice of a biological indicator depends upon selecting a strain with the optimum balance of desirable properties. Screening 20 strains of Bacillus spp. for sporulation on three defined media has shown the wide variation that occurs in requirements for sporulation and properties of the resultant spores. Comparison of germination index and moist heat resistance of resultant spores suggest that a combination of high germination index, high heat resistance and linear inactivation may not be possible.
Pseudomonas tolaasii on mushroom (Agaricus bisporus) crops: bactericidal effects of six disinfectants and their toxicity to mushrooms
Authors: WONG W.C. , PREECE T.F.
Published: March 2008

N‐Cetylpyridinium chloride, benzalkonium chloride, Cetrimide, bronopol (2‐bromo‐2‐nitropropane‐1,3‐diol), Panacide and Chloramine T were tested as possible disinfectants for use in growing mushrooms (Agaricus bisporus) where Pseudomonas tolaasii blotch is prevalent. The most effective materials in vitro against Ps. tolaasii where the quaternary ammonium compounds and bronopol in terms of the MIC and MCC tests. In 8 min ‘clean’ and ‘dirty’ tests incorporating yeast cells bronopol did not kill the pathogen, whereas the other five disinfectants did so. If mushroom casing (peat plus limestone) was added to these short duration tests the pathogen survived all six disinfectants. When tests with added casing were extended to 20 h, bronopol was very effective (cidal value 100 µg/ml) and the pathogen was not killed by the other five disinfectants. In experiments on agar plates, bronopol and chloramine T were stimulating to the growth of A. bisporus. Growing mushroom caps treated with bronopol remained white, whereas caps treated with the other five disinfectants turned brown within 30 min. It is thus likely that bronopol could be used to control the source of bacterial blotch epidemics in mushroom growing, which previous work has shown to be in the casing.
Characteristics of pectolytic clostridia isolated from soil and plants in Scotland
Authors: PERRY D. A.
Published: March 2008

Fifty‐six isolates of pectolytic clostridia were obtained from soils and plant roots; five were pigmented and resembled Clostridium puniceum while the remaining non‐pigmented forms were variable in the morphological and biochemical characteristics examined. The extent and inconsistency of the variations precluded the use of traditional taxonomic criteria and the bacteria could only be described as belonging to the butyric acid group. Many of the isolates grew satisfactorily on glucose and pectate media at temperatures as low as 10dEC.
A note on the isolation of salmonellas from environmental samples using three formulations of Rappaport's broth
Authors: FRICKER C.R. , GIRDWOOD R.W.A.
Published: March 2008

The efficiency of isolation of salmonellas from 412 seagull intestines and 247 polluted water samples was compared using three formulations of Rappaport's medium (RV, RV‐soya and R25). A modification of RV medium (RV‐soya) was shown to be the most efficient of the three media and it was shown that the duration of incubation of this medium could be restricted to 24 h. Inoculation ratios were compared for RV and RV‐soya and 1:100 was shown to be significantly better than 1:20. It is concluded that RV‐soya is at least as efficient as the standard RV medium and its use can therefore be recommended.
Synthesis and localization of α‐amylase and α‐glucosidase in Bacillus licheniformis grown in batch and continuous culture
Authors: PRIEST F.G. , THIRUNAVUKKARASU M.
Published: March 2008

In batch and continuous cultures of Bacillus licheniformis NC1B 6346 α‐amylase was invariably extracellular and could not be detected in the cytoplasm or cell surface. α‐Glucosidase however, was largely intracellular but at the end of exponential growth and during slow growth under Mg2+ limitation it was detected in the culture fluid. Both enzymes were susceptible to catabolite repression and glucose totally inhibited their synthesis in batch culture. In maltose‐limited chemostat culture, synthesis of both enzymes was maximal at D = 0.2/h and declined at higher growth rates. α‐Amylase synthesis was constitutive but α‐glucosidase synthesis was induced by maltose and maltotriose but not by methyl‐α‐D‐glucoside or phenyl‐α‐D‐glucoside. α‐Amylase was synthesized at pH 6.5 and above in maltose‐limited chemostat culture but not below this pH. Intracellular α‐glucosidase synthesis varied little with pH. Increasing temperature decreased the synthesis of both enzymes in chemostat culture to the extent that α‐glucosidase was undetectable at 50° C. Polar lipid composition varied with pH and temperature but there was no correlation between this and enzyme secretion. Moreover cerulenin, an antibiotic that inhibits protein secretion in some bacteria by interacting with the membrane had no effect on α‐amylase secretion but decreased the release of α‐glucosidase upon protoplast formation.
The cytotoxic and photodynamic inactivation of micro‐organisms by Rose Bengal
Authors: BANKS J.G. , BOARD R.G. , CARTER J. , DODGE A.D.
Published: March 2008

Rose Bengal was cytotoxic to the following bacteria at the concentrations given in parentheses (highest concentrations of dye in mol/1 at which growth occurred on nutrient medium): Brochothrix thermosphacta and Deinococcus radiodurans (1 times 10‐6 or less); Streptococcus, Micrococcus, Staphylococcus, Bacillus, Arthrobacter and Kurthia spp. (1 times 10‐5–1 x 10‐4), and Pseudomonas spp. and Enterobacteriaceae (5 times 10‐3–1 x 10‐2 or greater). These organisms were killed rapidly when suspended in illuminated (170 μE/m2/s) solutions of Rose Bengal (1 times 10‐4 mol/1) providing oxygen was present. Singlet oxygen was identified as the lethal agent, because the rate of killing was increased by dissolving the dye in deuterium oxide while the organisms were protected against photoinactivation by L‐histidine or crocetin. Yeasts from chilled foods were killed in illuminated solutions of Rose Bengal but a light intensity of 315 μE/m2/s was needed for a death rate comparable with that of bacteria. The yeasts present in a range of chilled meat and dairy products failed to form colonies on Rose Bengal (5 times 10‐5 mol/1) media exposed continuously to modest illumination (55–80 μE/m2/s).
A probability matrix for the identification of vibrios
Authors: DAWSON CHRISTINE A. , SNEATH P.H.A.
Published: March 2008

A probability matrix for computer‐assisted identification of vibrios has been constructed, based on the API 20E system. Data were gathered from 173 strains representing 31 taxa of vibrios and related organisms, from a variety of sources. The matrix was tested internally by four statistical programs. Program OVERMAT tested the separation and program MOSTTYP the discretion and homogeneity of the taxa. Most of the taxa were satisfactory but a few were less so; reasons for this are discussed. Program CHARSEP and program DIACHAR tested the separation and diagnostic values, respectively, of the characters used. The overall test error was 4–5%. The matrix was assessed externally by its performance in the identification of vibrio‐like strains isolated from freshwater. Of 243 wild strains, 79–4% were identified with ten taxa, with a Willcox score of ζ 0–99.
Comparative peptide specificity of cell wall, membrane and intracellular peptidases of group N streptococci
Authors: KOLSTAD J. , LAW B.A.
Published: March 2008

Solubilized cell walls of group N streptococci contain two electrophoretically distinct peptidases, one of which hydrolysed trileucine only, while the second hydrolysed a wide range of di‐ and tripeptides. Neither enzyme possessed leucine aminopeptidase or endopeptidase activity. Four and three peptidases, respectively, were separated in intracellular extracts of Streptococcus lactis subsp. lactis and Strep, lactis subsp. cremoris produced by osmotic lysis of spheroplasts. In contrast with the cell‐wall extracts, two of the peptidases had broad specificites, though only one of these hydrolysed trileucine. Purified membranes of Strep. lactis subsp. lactis contained only one electrophoretically distinct peptidase of very narrow specificity. There were small differences between the numbers of peptides hydrolysed by cell wall preparations from milk‐grown or broth‐grown cells.
Technical note
Authors: VANCE I. , HUNT R.J.
Published: March 2008

Modifications to a French pressure cell, designed for the disruption of microbes, are described which allow the apparatus to be used for the incubation of anaerobic bacteria at temperatures and pressures up to 75°C and 500 bar.
Phytic acid changes in soybeans fermented by traditional inoculum and six strains of Rhizopus oligosporus
Authors: SUTARDI  , BUCKLE K.A.
Published: March 2008

Tempeh was prepared from Delmar variety soybeans inoculated with the traditional Indonesian inoculum (usar) and six pure culture strains of Rhizopus oligosporus. The strains BTU3K1 and CT11K2 produced the best quality tempeh. The phytic acid content of soybeans was reduced from 1mD07% in whole dry soybeans to 0mD67–0mD75% in tempeh. Most mould strains did not have a significantly different effect on reducing the phytic acid content in tempeh, although the traditional inoculum was significantly different to strains CTU7K2, BTU3K1, BT1K4 and CT11K2.
Mutagenesis of Clostridium acetobutylicum
Authors: BOWRING SARAH N. , MORRIS J.G.
Published: March 2008

Mutagenesis of the obligate anaerobe Clostridium acetobutylicum was best accomplished using agents (e.g. ethyl methane sulphonate or N‐methyl‐N'‐nitro‐N‐nitrosoguanidine) which are believed to act by a direct mutagenic mechanism. Other agents (e.g. u.v. radiation) whose effectiveness relies on misrepair of damaged DNA via an error‐prone pathway, were poor mutagens of this organism. Procedures are described which readily yielded a variety of auxotrophic and other useful mutant strains of Cl. acetobutylicum and related saccharolytic clostridia.
The rumen microbiology of seaweed digestion in Orkney sheep
Authors: ORPIN C.G. , GREENWOOD Y. , HALL F.J. , PATERSON I.W.
Published: March 2008

The microbial populations of the rumens of seaweed‐fed and pasture‐fed Orkney sheep were examined. The populations in the pasture‐fed sheep were similar to those of other domestic ruminants fed on land plants, but those of the seaweed‐fed animals showed major differences in the dominant species. Total ciliate populations were quantitatively similar, but in the seaweed‐fed animals Dasytricha ruminantium was one of the most dominant species. No phycomycete fungi or cellulolytic bacteria were found in the seaweed‐fed animals, and the bacterial population was dominated by Streptococcus bovis, Selenomonas ruminantium, But yrivibrio fibrisol‐vens and lactate‐utilizing species. Electron microscopy revealed that spirochaetes and an unidentified filamentous bacterium were probably of major significance in seaweed digestion. The ability of bacterial strains from both groups of animals to metabolize plant and algal constituents was examined.
Fermentation of milk by Streptococcus salivarius subspecies salivarius and Streptococcus salivarius subspecies thermophilus and their use to the yoghurt manufacturer
Authors: Marshall V.M. , Cole W.M. , Phillips B.A.
Published: March 2008

Unlike Streptococcus salivarius subspecies thermophilus, Streptococcus salivarius subspecies salivarius fails to grow symbiotically in milk in the presence of Lacto‐bacillus bulgaricus, does not produce large quantities of the flavour volatiles, acetal‐dehyde or diacetyl and is unable to stimulate growth of Lact. bulgaricus by producing formate. Although Strep, salivarius subspecies salivarius and thermophilus have similar DNA base composition and belong in the same DNA homology group, the former is unsuitable for milk fermentations such as yoghurt because fermentation of milk using this organism results in products with poor flavour, aroma and texture.
Identification of fusobacteria in a routine diagnostic laboratory
Authors: Bennett K.W. , Duerden B.I.
Published: March 2008

A scheme for differentiating Fusobacterium spp. and Leptotrichia spp. from Bac‐teroides spp, was devised after examining 114 strains of fusobacteria and asac‐charolytic bacteroides (17 reference strains and 97 clinical isolates). Sensitivity to a 300 μg/ml plate of phosphomycin and an acid reaction on a lysine plate were found to be reliable for differentiating Fusobacterium spp. and L. buccalis from Bacteroides Using a short set of simple cultural and biochemical tests, isolates could be identified as F. necrophorum, F. necrogenes, F. nucleatum, F. varium or L. buccalis. These tests were: indole, lecithinase, phosphatase, DNase and gas production, aesculin and casein hydrolysis, greening of casein/methylene blue agar, nitrite reduction, bile tolerance and haemolysis on horse blood agar.
Effect of unsaturated fatty acids in growth inhibition of some penicillin‐resistant and sensitive bacteria
Authors: Raychowdhury M.K. , Goswami R. , Chakrabarti P.
Published: March 2008

The growth of two penicillin‐resistant Gram‐positive bacteria, Bacillus licheniformis (749/C, penicillin G‐resistant) and Staphylococcus aureus (metR 18, methicillin‐resistant) and one Gram‐negative strain, Escherichia coli (cloxacillin‐resistant) as well as that of their wild counterparts was inhibited by the long‐chain unsaturated fatty acids, linoleic, linolenic and arachidonic acid. The minimum inhibitory concentrations (MIC) of all the fatty acids were found to be 4–6 μg/ml for Staph. aureus (metR 18 & wild), 8–30 μg/ml for B. licheniformis (749/C & wild) and 70–90 μg/ml for E. coli (cloxacillin‐resistant & wild). The inhibitory activity increased as the number of double bonds in the fatty acids increased. In most instances the concentrations of fatty acids required to inhibit the growth of the penicillin‐resistant strains were lower than that required for their sensitive counterparts. This inhibition of growth in the presence of fatty acids may be due to an increase in permeability of the membrane as evidenced by the measurement of the leakage of 260 nm absorbing material and fluidity.
Spatial and temporal changes of nitrifying bacterial populations in fish ponds of differing management practices
Authors: Jana B.B. , Roy S.K.
Published: March 2008

Practices of three types of fish farming (polyculture, monoculture and traditional) resulted in density differences of ammonia oxidizers which occurred in maximal numbers in polyculture and minimal in traditional systems. This distribution pattern was attributed to their nutrient status. The sine and cosine waves of periodic functions were a good fit with the seasonal data showing a sharp peak in winter. The correlation studies revealed that seasonal changes of ammonia oxidizers of these fish ponds were largely dependent upon pH, concentrations of different forms of nitrogen, phosphate, dissolved oxygen, organic carbon and organic matter as well as the ratio of C to N.
Improvements in the microtitre GM1 ganglioside enzyme‐linked immunosorbent assay for Escherichia coli heat‐labile enterotoxin
Authors: Bongaerts G.P.A. , Bruggeman‐Ogle K.M. , Moutok R.P.
Published: March 2008

A variant of the microtitre GM1‐ELISA for Escherichia coli heat‐labile enterotoxin was studied. The test was improved by both reducing the assay time from 2½ d to 8 h and by determining the most appropriate GM1 coating concentration. Coating the plates with >3 μg of GM1/ml yielded a maximal sensitivity and ensured a linear relationship between the enterotoxin concentration and the extinction observed when using the final assay‐procedure. Thus an optimal accuracy was obtained. This ELISA was 4‐ to 8‐times more sensitive than the Vero cell monolayer assay. The sensitivity of this ELISA and of the Chinese hamster ovary cell monolayer assay were identical.
The release of dipicolinic acid during heating and its relation to the heat destruction of Bacillus stearothermophilus spores
Authors: Mallidis C.G. , Scholefield J.
Published: March 2008

The rates of dipicolinic acid (Dpa) release and the rates of death were studied for spores of five strains of Bacillus stearothermophilus. It was observed that a highly significant relationship exists between the rate of Dpa release and rate of spore death for the four out of five strains tested and for all test temperatures. At 115d̀C the rate of Dpa release was found to be faster than the rate of death, equal at 120d̀C and slower at 125d̀C. The role of Dpa in heat resistance was considered and a theory is proposed to explain the mechanism by which the heat resistance of bacterial spores is overcome.
Epiphytic bacteria: development of a method for determining respiring bacteria on leaves
Authors: Kidd‐Haack S. , Bitton G. , Laabes Denise
Published: March 2008

A method was developed for studying the total numbers and the proportion of active bacteria on leaf surfaces. It involves staining gelatin impressions of leaves treated with an electron transport system indicator, 2‐(p‐iodophenyl)‐3‐(p‐nitrophenyl)‐5‐phenyl tetrazolium chloride (INT). The method is rapid, inexpensive and allows simultaneous observation of numbers, ecology and respiratory activity of epiphytic bacteria. The total numbers of epiphytic bacteria for four species of aquatic plants varied between 0.6 to 10.2 times 106/cm2. The proportion of active bacteria on leaves of aquatic plants ranged from 2.2 to 42.9%. The method was also applied to a comparison of surface fouling of glass slides and aquatic leaf surfaces, indicating significant differences in numbers of bacteria but little difference in the proportion active on the two surfaces.
A note on a selective agar medium for the enumeration of Flavobacterium species in water
Authors: Flint K.P.
Published: March 2008

A selective nutrient agar medium containing kanamycin at 50 μg/ml was developed for the isolation and enumeration of yellow‐pigmented colonies from the River Sowe, Coventry. Such organisms were shown to be members of the heterogeneous genus Flavobacterium. Typically, yellow pigmented colonies constituted less than 10% of the colonies on nutrient agar alone but up to 70% on nutrient agar plus kanamycin. This medium is a useful addition to the range of media available for the isolation and further ecological study of particular species of this important group of micro‐organisms.
Possible role of calcium in the formation of active extracellular proteinase by Pseudomonas fluorescens
Authors: McKellar R. C. , Cholette H.
Published: March 2008

The requirement for calcium during synthesis of extracellular proteinase by Pseudomonas fluorescens B52 was examined. Synthesis was monitored using cells resuspended at high density in fresh growth medium. Optimum enzyme production was found with cells grown to mid‐logarithmic phase in mineral salts medium containing calcium chloride (1.0 mmol/l). Inhibition of synthesis by EDTA addition was rapid, similar to the effect produced by chloramphenicol, an inhibitor of translation. Appearance of enzyme initiated by calcium addition to depleted cells was rapid and was dependent on de novo protein synthesis. Sephadex G‐100 chromatography of L‐[4,5‐3H]leucine‐labelled cell‐free supernatant liquids revealed that, in the absence of calcium, a low molecular weight (12000–14000 daltons) irreversibly inactive ‘precursor’ of the proteinase was formed. The results are consistent with the hypothesis that calcium is required for structural integrity of the proteinase as well as for activity.
Influence of the growth cycle on the fatty acid and menaquinone composition of Streptomyces cyaneus NCIB 9616
Authors: Saddler G. S. , Goodfellow M. , Minnikin D. E. , O'Donnell A. G.
Published: March 2008

Dried biomass of Streptomyces cyaneus NCIB 9616 harvested at 1, 3, 7, 10 and 14 d from a liquid culture was degraded by alkaline methanolysis and the fatty acid methyl esters released examined quantitatively by gas chromatography. Isoprenoid quinones were extracted with petroleum ether and methanolic saline, purified by thin‐layer chromatography and quantified by high performance liquid chromatography. Data for each component were plotted against time. The results showed that at the beginning of logarithmic growth there was a small quantitative shift in the fatty acid composition but, the fatty acid profiles remained relatively constant during both the logarithmic and stationary phases of growth. In contrast, the isoprenoid quinone composition depended markedly on the stage of growth. These results indicate that valid comparison of isoprenoid quinone profiles requires that sampling take place at defined stages of the growth cycle.
A comparison of media and methods for the recovery of Yersinia enterocolitica and Yersinia enterocolitica‐like bacteria from milk containing simulated raw milk microfloras
Authors: Walker S. J. , Gilmour A.
Published: March 2008

A number of plating and enrichment media proposed for the isolation of Yersinia enterocolitica from foodstuffs were examined for their ability to recover the type strains of Y. enterocolitica sensu stricto, Y. intermedia, Y. frederiksenii and Y. kristensenii. Nine selective plating media were evaluated for the quantitative recovery of the type strains in pure culture, and their inhibition of other organisms typical of both milk and enteric microfloras. Cefsulodin‐irgasan‐novobiocin (CIN) agar, incubated for 48 h at 25°C, allowed a high recovery of all the Yersinia spp. and was the most selective medium. The same four type strains were added to UHT milk that had been previously inoculated with bacteria to simulate either freshly drawn or cold stored milk microfloras. Twenty‐six enrichment procedures (including cold enrichment, selective enrichment at higher temperatures, two‐step procedures and a post‐enrichment alkali treatment) were assessed for the efficiency of recovery of the Yersinia spp. Pre‐enrichment in trypticase‐soy broth (TSB) for 24 h at 22°C followed by selective enrichment in bile‐oxalate‐sorbose (BOS) medium for 5 d at 22°C and plating on CIN agar (48 h at 25°C) allowed the greatest increase in the numbers of Yersinia spp. and maximum inhibition of the competing microflora.
Starch utilization by the human large intestinal microflora
Authors: Macfarlane G. T. , Englyst H. N.
Published: March 2008

High levels (2–565 units/g) of amylase activity were observed in human faeces. Over 92% of amylase activity in faeces obtained from healthy persons was extracellular, whereas only about 9% of activity was associated with particulate material and washed cells. Bacterial cell‐bound amylases were considerably more efficient in breaking down starch, however, than were the soluble enzymes which occurred in cell‐free faecal supernatant fluids. Cell population densities of anaerobic starch‐hydrolysing bacteria in the stools of ten persons ranged from 1.1 × 1010 to 3.3 × 1012/g of faeces. Identification of 120 starch‐hydrolysing colonies isolated from the stools of six subjects showed that the predominant amylolytic bacteria belonged to the genera Bifidobacterium, Bacteroides, Fusobacterium and Butyrivibrio. Mixed populations of gut bacteria rapidly fermented starch with the production of volatile fatty acids and organic acids. Lactate was observed to be a major, though transient intermediate during starch fermentation by these cultures. Approximately 60% of starch utilized was converted to volatile fatty acids, which in the human colon would be potentially available for absorption.
The Brownian diffusion of dormant and germinating spores of Bacillus megaterium
Authors: Harding S. E. , Johnson P.
Published: March 2008

Light scattering techniques provide a non‐destructive probe into structural aspects concerning the dormancy, heat resistance and germination of bacterial spores. Quasi‐elastic light scattering techniques are applied to a study of the diffusion and scaling properties of dormant and germinating Bacillus megaterium spores (strain KM). A translational coefficient of (5.01 ± 0.10) × 10‐9 cm2/s is obtained for the dormant spore, with little apparent change during the early stages of germination. Dormant and germinated spores, however, give different scaling characteristics. The significance of these observations in terms of theories concerning the dormancy and heat resistance of spores is discussed.
The metabolism of carbaryl by three bacterial isolates, Pseudomonas spp. (NCIB 12042 & 12043) and Rhodococcus sp. (NCIB 12038) from garden soil
Authors: Larkin M. J. , Day M. J.
Published: March 2008

At an alkaline pH and in aqueous solution, carbaryl hydrolyses to form 1‐naphthol, methylamine and carbon dioxide, but it is much more stable at an acid pH. Two bacteria isolated from garden soil, Pseudomonas sp. (NCIB 12042) and Rhodococcus sp. (NCIB 12038), could grow on carbaryl as sole carbon and nitrogen source at pH 6.8 but failed to metabolize carbaryl rapidly. Both could use 1‐naphthol as sole carbon source and NCIB 12042 metabolized 1‐naphthol via salicylic acid which induced higher expression of enzymes in the pathway. Strain NCIB 12038 metabolized 1‐naphthol via salicylic and gentisic acids. In contrast, Pseudomonas sp. (NCIB 12043) was selected in a soil perfusion column enrichment at pH 5.2 and metabolized carbaryl rapidly to 1‐naphthol and methylamine. 1‐Naphthol was metabolized via gentisic acid. Neither salicylate nor gentisate induced higher expression of enzymes for 1‐naphthol catabolism in NCIB 12038 and NCIB 12043.
Evaluation of selective media for enumeration of yeasts during wine fermentation
Authors: Heard G. M. , Fleet G. H.
Published: March 2008

The growth of individual species of yeasts during wine fermentations was measured by plating wine samples on malt extract, ethanol sulphite and lysine agars. Colonies of Saccharomyces cerevisiae dominated on plates of malt extract agar and sometimes masked the presence of other non‐Saccharomyces species. Lysine agar suppressed the growth of S. cerevisiae and enabled the enumeration of non‐Saccharomyces species such as Kloeckera apiculata, Candida stellata and Saccharomycodes ludwigii. The growth of non‐Saccharomyces yeasts on ethanol sulphite agar was variable.
Survey of p‐cresol assimilating bacteria: Characterization and identification of a p‐cresol utilizing bacterium
Authors: El‐Mansi E. M. T.
Published: March 2008

A survey of 110 bacterial strains drawn from various ecosystems yielded 10 capable of growth on p‐cresol. Of these, eight were Gram‐negative and two Gram‐positive. One Gram‐negative and both Gram‐positive strains metabolized p‐cresol via 4‐methylcatechol, the others initiated attack by hydroxylation of the methyl group and used the protocatechuate pathway. These included Pseudomonas alcaligenes, Ps. testosteroni, four other Pseudomonas species and an unidentified organism, the crude extract of which oxidized p‐cresol without requirement for either electron donor or acceptor, although inclusion of phenazine methosulphate stimulated activity. The conversion of p‐cresol to p‐hydroxybenzylalcohol catalysed by the PMS‐dependent p‐cresol methylhydroxylase was linked to the electron transport chain with molecular oxygen acting as the ultimate electron acceptor. Successive subculturing in the absence of the aromatic substrate led to the eventual loss of the organism's ability to metabolize p‐cresol. The organism was assigned to the genus of Alcaligenes.
Evaluation of recovery media for heated spores of Bacillus stearothermophilus
Authors: Mallidis C. G. , Scholefield J.
Published: March 2008

The effects of different media, additives, pH and incubation temperatures were studied on the recovery of heat‐treated spores of Bacillus stearothermophilus. Raising the pH from 6.5 to 7.3 increased the shoulder and decreased the subsequent exponential rate of inactivation with some of the media. Addition of starch or charcoal caused a significant increase in the level of recovery. No significant differences were observed by using two incubation temperatures (50° or 60°C). Yeast‐peptone‐tryptone‐dextrose medium plus starch was found to be the best of the media used.