bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyanobacteria‐cyanophage Interactions in Continuous Culture
Authors: BARNET YVONNE M. , DAFT M. J. , STEWART W. D. P.
Published: March 2008

When the filamentous Plectonema boryanum 594 or the unicellular Aphanothece stagnina were grown in chemostats with phages LPP‐DUN1 and Aph‐1, respectively, an initial series of reciprocal oscillations in cyanobacterial and phage numbers occurred; their magnitudes decreased successively until an equilibrium population of cyanobacteria and virus was established in each system. Evolution of the protagonists occurred as the interactions proceeded. Most of the A. stagnina population appeared resistant to Aph‐1 at the end of the experiment. Two types of resistant P. boryanum, designated PR1 and PR2, were isolated. PR1 was resistant to wild‐type LPP‐DUN1 but susceptible to a mutant phage; PR2 was unaffected by the phage. The sequence of appearance and interaction of mutant phage and P. boryanum accounted for the initial fluctuations in population numbers, and the coexistence of host and pathogen in the climax population. Plectonema boryanum PR2 grew more slowly than wild‐type, or PR1 and competed poorly with them in the absence of phage. The ecological implications of the results are discussed.
Bacteriological Examination of Pipeline Milking Machines by Rinsing the Entire System
Authors: RICHARD J.
Published: March 2008

The results of bacteriological examination of rinses of the entire systems of 12 pipeline milking machines were compared with a similar examination of the milk collected while they were used for milking. The machines were cleaned in three different ways and showed varying degrees of complexity. There was a close correlation between the results when the milk was collected with the maximum of cleanliness during milking. This is attributed to the localization of most of the micro‐organisms present in the milking machine in the junctions and complex parts of the machine and not on the surface of the equipment, so they are removed with the same efficiency by cold water or warm milk. The number of micro‐organisms retrieved by water during successive rinses (or by the milk during milking) decreased at a rate which depended either on the level of initial contamination of the equipment, its design or on the types of micro‐organisms present. Recommendations are made for the interpretation of the results of rinsing.
The Classification, Identification and Nomenclature of Agrobacteria
Authors: HOLMES B. , ROBERTS P.
Published: March 2008

In order to devise a scheme for the identification and differentiation of agrobacteria, 50 strains of Agrobacterium, mostly those maintained in the National Collection of Plant Pathogenic Bacteria, were separated into four clusters when subjected to numerical taxonomic analysis. For the two major clusters, regardless of the phytopathogenic effect of the strains, we would adopt the species names A. tumefaciens and A. rhizogenes. A third cluster merits the use of the specific name A. rubi whilst a hitherto unrecognized fourth cluster of yellow‐pigmented isolates may constitute a fourth species in the genus. The species name A. radiobacter is rejected as this species is synonymous with A. tumefaciens and the latter, being the type species of the genus, takes priority. To indicate the phytopathogenic effect of strains within our four Agrobacterium clusters we would use the terms: saprophytic state, tumourigenic state and rhizogenic state. Revised descriptions, without regard to phytopathogenic effect, are given for A. tumefaciens, A. rhizogenes and A. rubi.
Evaluation of Virulence Test Procedures for Yersinia enterocolitica Recovered from Foods
Authors: LEE W. H. , SMITH R. E. , DAMARÉ J. M. , HARRIS M. E. , JOHNSTON R. W.
Published: March 2008

Recently a heat stable toxin (ST) and the vw factors of the plague bacteria were identified in Yersinia enterocolitica recovered from human infections. The vw factors were reported to be associated with a plasmid of 42‐46 M Daltons in size and were essential for the expression of virulence. With this knowledge virulence tests were developed which allowed us to assess the virulence potential of food‐borne Y. enterocolitica regardless of biotypes or serotypes. The tests evaluated were: (1) rapid presumptive test for the virulence plasmid; (2) gel electrophoretic confirmation of the virulence plasmid; (3) Laird's qualitative oral feeding test with thirst stressed mice; (4) quantitative LD50 determination by i.p. injection of the mouse lethal (i.e. serotype 0:8) strains in saline; (5) quantitative LD50 determination of mouse non‐lethal (i.e. serotype 0:3) strains by i.p. injection of these strains suspended in 1 ml of 10% iron dextran saline solution for virulence enhancement. These tests were evaluated with the serotypes 0:3 and 0:8 strains associated with human infections with and without the virulence plasmid with reproducible results. Then the virulence tests procedures were applied to 79 food isolates. The virulence plasmid was detected only in the Nilehn biotype 2, 3 and 4 strains, but it was absent in Nilehn biotype 1 or the atypical strains that ferment rhamnose. The virulence of food and clinical isolates of Y. enterocolitica can be assayed fairly accurately with the above tests.
Sensitivity to Lysostaphin as a Criterion for the Identification of Staphylococci from Animal Origin
Authors: GUTIÉRREZ L , MENES I. , GARCIA M. L. , MORENO B.
Published: March 2008

A total of 195 Gram positive, catalase positive cocci, isolated from ovine mastitis, abscesses in slaughtered animals and parasitic pulmonary lesions in lambs were tested for glucose fermentation, anaerobic growth in thioglycollate medium, coagulase production and susceptibility to the lytic action of lysostaphin. On the basis of lysostaphin sensitivity, 192 strains were classified as staphylococci. The number of cultures able to produce acid anaerobically from glucose, or giving a positive result in the test of Evans and Kloos was lower. A good correlation among these three tests was not observed. Ninety‐seven of the strains tested gave a positive coagulase reaction. Sensitivity to lysostaphin could not be used as a criterion for the differentiation of coagulase positive and coagulase negative strains. The turbidimetric method employed for the assessment of lysostaphin sensitivity is discussed.
Distribution of Isoprenoid Quinones in Halophilic Bacteria
Authors: COLLINS M. D. , ROSS H. N. M. , TINDALL B. J. , GRANT W. D.
Published: March 2008

Menaquinones were the sole isoprenoid quinones found in 28 of the 34 halophilic organisms examined. Unsaturated and dihydrogenated menaquinones with eight isoprene units were found in some alkalophilic halophiles and representatives of the genera Halobacterium and Halococcus. Brevibacterium halotolerans and Micrococcus halobius possessed major amounts of unsaturated menaquinones with seven and eight isoprene units, respectively. Actinopolyspora halophila possessed complex mixtures of partially hydrogenated menaquinones with tetrahydrogenated menaquinones with nine isoprene units predominating. Vibrio costicola possessed both menaquinones and ubiquinones with eight isoprene units. Ectothiorhodospira halophila, Flavobacterium halmephilum, Paracoccus halodenitrificans and Pseudomonas beijerinkii contained ubiquinones as their sole respiratory quinones. Ectothiorhodospira halophila possessed major amounts of ubiquinones with eight isoprene units whereas ubiquinones with nine isoprene units predominated in Flavobacterium halmephilum, Paracoccus halodenitrificans and Pseudomonas beijerinkii.
Factors influencing the production of extracellular proteinase by Pseudomonas fluorescens*
Authors: McKellar R. C.
Published: March 2008

Abstract—

Some of the factors influencing the production of extracellular proteinase by three strains of Pseudomonas fluorescens were studied. Tryptic Soy Broth supported good growth and enzyme production by all three strains. Poor enzyme yields resulted from growth in Nutrient Broth, Brain Heart Infusion and Peptone Yeast Extract. Addition of 0.2% (w/v) Skim Milk Powder to citrate mineral salts or Nutrient Broth stimulated enzyme production. Maximum yields of enzyme on mineral salts medium containing skim milk were obtained when pyruvate was the source of carbon; activity was low when glucose or citrate were used. Glutamine, when added as the sole carbon and/or nitrogen source, supported enzyme synthesis. At 5, 10, 15 and 20°C enzyme levels increased with increasing skim milk concentration. At 5°C enzyme activity was approximately 55% of that found at 20°C. A filter‐sterilized or autoclaved high‐speed centrifuged supernatant from skim milk strongly induced the proteinase. A small molecular weight (<5000) fraction obtained from a Sephadex G‐100 separation of skim milk supernatant actively stimulated enzyme production; fractions containing large molecular weight proteins were ineffective inducers. The maximum rate of enzyme production occurred during the late log and early stationary phases of growth at both 5 and 20°C.
Germination and outgrowth of single spores of Clostridium botulinum and putrefactive anaerobes
Authors: Roberts T.A. , Thomas Josephine A.
Published: March 2008

Single spores of putrefactive anaerobes (PAs) germinated more slowly than those of Clostridium botulinum types A & B, with calculated times for 10% germination from 2 to 302 d. If PA spores were used in inoculated pack studies to simulate the response of Cl. botulinum, the likelihood of growth of Cl. botulinum would be underestimated.
Detached leaf enrichment: a method for detecting small numbers of Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria in seed and symptomless leaves of tomato and pepper
Authors: Sharon Edna , Okon Y. , Bashan Y. , Henis Y.
Published: March 2008

A method for detecting 101‐102 cells of phytopathogenic bacteria (Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria) in either tomato or pepper seed was developed. The method is based on the enrichment of the compatible pathogen inside a detached leaf of its host when placed on a water agar medium. It was found to be superior to the diagnostic growth media method commonly used and to permit the detection of the pathogens in symptomless plants.
A study of isolation procedures for multiple infections of Salmonella and Arizona in a wild marsupial, the quokka (Setonix brachyurus)
Authors: Hart R. P. , Iveson J. B. , Bradshaw S. D. , Speed T. P.
Published: March 2008

Rectal swabs and faeces were used in the regular sampling for salmonellas and Arizonas from a heavily‐infected population of a marsupial, the quokka (Setonix brachyurus). The media used were strontium selenite A and strontium chloride B enrichment broths, with subculture onto modified bismuth sulphite agar and deoxycholate citrate agar. A study of sampling, enrichment, sub‐culture and colony selection procedures produced an optimal scheme giving high yields but consistent with reasonable economy of time and materials. A three‐swab sample was taken and inoculated into the two enrichment media, and with each enrichment subjected to three subcultures. The absolute efficiency of this procedure was greater than 80% (and confirmed by a serological method), compared with only 67% for a single swab in a single enrichment. Recovery of some serotypes depended on the media used; e.g. Arizonas could not be recovered satisfactorily from strontium chloride B enrichment. Faeces samples were found to be greatly superior to rectal swabs for detecting salmonellas and arizonas but they were less convenient in field studies. In a comparison of rectal swabs and faeces samples where the actual concentration of salmonellas was known, it was found that the efficiency of rectal swabs approached 100% if there were more than 103 salmonellas/g faeces, but this declined to approximately 50% if there were 102‐103 salmonellas/g faeces and only 25% if there were less than 102 salmonellas/g faeces. A new statistical procedure was introduced for comparing the number of isolations from two methods, and this should be of use in similar methodological studies.
A note on the yeast flora associated with fermentation of mango
Authors: Suresh E.R. , Onkarayya H. , Ethiraj S.
Published: March 2008

Fifteen morphologically different groups of yeasts consisting of Metschnikowia pulcherrima, Trichosporon cutaneum, Kloeckera apiculata, Torulopsis Candida, Tor. glabrata. Tor. apicola, Candida tropicalis, Cand. krusei, Cand. sorbosa, Cand. diversa, Pichia terricola, Pic. membranaefaciens, Hyphopichia burtonii, Rhodotorula graminis and Aureobasidium pullulans were isolated from fresh, fermenting and fermented juice of two varieties of mango. This is the first report on the study of yeast flora of mango and also on the occurrence of Hyp. burtonii on fruits.
Characteristics of lactic acid bacteria isolated from vacuum‐packaged beef
Authors: Hitchener Beverley J. , Egan A.F. , Rogers P.J.
Published: March 2008

The characteristics of 177 psychrotrophic lactic acid bacteria isolated from vacuum‐packaged fresh beef have been studied. Eighteen isolates were identified as Leuconostoc mesenteroides and the remainder were lactobacilli. None of these could be identified down to a species level and they were considered to be atypical streptobacteria or atypical betabacteria. Atypical streptobacteria produced both isomers of lactic acid and did not ferment lactose and maltose. Atypical beta‐bacteria produced only L(+) lactic acid. The nature of the isolates varied considerably from pack to pack. The API 50 lactobacillus identification system proved useful in studying these organisms.
Nitrate reduction by Pseudomonas spp.: antagonism by fermentative bacteria
Authors: HOrsley R.W. , Roscoe José V. , Talling Ida B.
Published: March 2008

The reduction of nitrate by Pseudomonas denitrificans in a culture medium containing glycerol, yeast extract and 700 mg/1 NO3–N, was antagonized by Aeromonas hydrophila, Escherichia coli and Enterobacter aerogenes. Nitrate reduction by Ps. denitrificans in mixed culture with a fermentative heterotroph was inhibited when 100–150 mg/1 NO2–N had accumulated in the medium. The number of Ps. denitrificans declined concomitantly with the appearance of NO2 in the culture medium, but there was only a slight increase in the numbers of fermentative hetero‐trophs. The fermentative heterotrophs did not antagonize nitrate reduction by Ps. denitrificans, when the culture medium contained 140 mg/1 NO3–N. When mixtures of equal parts of Ps. denitrificans and Esch. coli cultures were added to autoclaved river water relatively high concentrations of NO2 were produced from the nitrate present in the water.
The effect of sterols and haemin on the growth of the rumen ciliate Ophryoscolex caudatus and some other Entodiniomorphid protozoa
Authors: Coleman G.S. , Reynolds Diana J.
Published: March 2008

Seven isolates of Ophryoscolex caudatus have been cultured anaerobically in vitro (at a population density of 56/ml) for an average of 18 months each in the presence of bacteria on a reduced buffered salts medium containing prepared fresh rumen fluid with the daily addition of ground wheat and dried grass and with twice weekly dilution of the culture with an equal volume of fresh medium. The ground wheat and dried grass could be replaced by ground wheat coated with β‐sitosterol, stigmasterol, ergosterol or α‐spinasterol and with β‐sitosterol the population density increased to 110/ml. Haemin further increased the population density obtained in the presence of sterol by 9–160%. The population density of cultures of Epidinium ecaudatum caudatum was also increased by sterols and haemin, that of Polyplastron multivesiculatum by sterols only, and some sterols and haemin, under certain conditions, increased that of Entodinium caudatum.
Defined minimal media for the growth of prototrophic and auxotrophic strains of Bacillus stearothermophilus
Authors: Lee Y.H. , Brown M.R.W. , Cheung H.Y.
Published: March 2008

Minimal chemically defined media for Bacillus stearothermophilus were developed at 60°C and quantitative requirements for each nutrient were determined. A prototrophic strain of B. stearothermophilus was grown in medium containing only glucose and mineral salts whereas auxotrophic strains in addition required biotin, thiamine, nicotinic acid and DL‐methionine. Metabolic interaction between L‐valine and L‐leucine was observed with auxotrophic organisms. The presence of L‐leucine in minimal medium necessitated the addition of L‐valine. Growth took place in the absence of both amino acids.
Taxonomy of bacteria isolated from a coastal, marine fish‐rearing unit
Authors: Austin B.
Published: March 2008

Phenetic data on almost 600 aerobic, heterotrophic bacteria from a marine fishrearing unit were collected and analysed using numerical taxonomic techniques. Reference strains, representing 42 taxa were included in the analyses. At similarity levels of 85% or above, with analyses prepared from the simple matching coefficient (SSM), 81% of the isolates were recovered in eight major and 43 minor phena. Five of the major phena were equated with Acinetobacter calcoaceticus, Photobacterium phosphoreum and Vibrio spp. (three groups); the three unidentified phena contained Gram negative rods with polar flagella which were considered to be intermediate between Cytophaga/Flexibacter and Flavobacterium (two phena), and Gram variable rods. The surface of healthy turbot (Scophthalmus maximus L.) was populated by a diverse array of bacteria, including Alcaligenes faecalis, Bacillus firmus, Photobacterium angustum,‘Photobacterium logei’ and Pseudomonas fluorescens. Taxa, isolated as pure culture growth from within the lesions of moribund animals, included Alteromonas haloplanktis and unidentified Gram negative, budding bacteria. Vibrio anguillarum was not recovered from any turbot suspected of suffering from ‘vibriosis’.
A note on the determination of the sporulation septum type inStreptomyces
Authors: Hardisson C. , Moraleda Pilar , Manzanal M.B.
Published: March 2008

The form of the sporulation septum inStreptomycesappears to have taxonomic value but its demonstration has hitherto required electron microscopic study of ultrathin sections. This lengthy procedure has limited the use of sporulation to provide characters for identification and taxonomic purposes. It has now been shown that there is good correlation between the width of the sporulation septum and the type of sporulation, and that the septum can be measured in negatively stained preparations. The latter technique is relatively simple and rapid, and we now advocate its use to give an additional character forStreptomycestaxonomy.
Isolation of new types of sulphate‐reducing bacteria from estuarine and marine sediments using chemostat enrichments
Authors: Keith S.M. , Herbert R.A. , Harfoot C.G.
Published: March 2008

Anaerobic chemostat enrichments have been successfully employed to isolate acetate‐utilizing, sulphate‐reducing bacteria from sediments in the Tay estuary. Several different morphologically and nutritionally versatile types of sulphate‐reducing bacteria have been isolated by this means which has proved especially useful when they are present in low numbers. The principal advantage of this method is that strict anaerobes such as sulphate‐reducing bacteria can be isolated in a controlled and reproducible enrichment system at low growth rates.
Microbial spoilage of luncheon meat prepared in an impermeable plastic casing
Authors: Bell R.G. , Gill C.O.
Published: March 2008

Freshly cooked luncheon meat in a plastic (PVDC) casing had an aerobic plate count of about 102/g. The flora was composed of approximately equal numbers of Bacillus and Micrococcus spp. Storage at 10°C for 42 d produced little increase in bacterial numbers, or changes in pH value or glucose content at either the surface or core of the luncheon meat. Storage at 25°C allowed Bacillus spp. to proliferate at the surface. The inhibitory effect of salt and nitrite on the growth of heated Bacillus spores at low redox potentials probably accounts for the absence of growth within the product. Growth at the surface was accompanied by a fall in pH (6.8 to 6.2) and an increase in glucose (1.6 to 3.6 mg/g) and L(+)‐lactic acid (1.2 to 2.3 mg/g). By day 14 the Bacillus spp. had been displaced by a Streptococcus sp. (107/g) which remained the dominant organism until the experiment ended on day 28. The pH continued to fall from 5.7 on day 14 to 5.2 on day 28, the L(+)‐lactic acid rose to 6.1 mg/g, but the glucose remained constant at the day 7 level (3.6 mg/g). This indicates that glucose converted to lactic acid was largely replaced by hydrolysis of the starch portion of the luncheon meat mediated by amylases produced by the Bacillus microflora. It appears that growth of the Streptococcus is dependent upon the denitrifying activities of the initial Bacillus flora reducing the concentration of nitrite ion to non‐inhibitory levels.
Viability of heat‐stressed cells of micro‐organisms as influenced by pre‐incubation and post‐incubation temperatures
Authors: Katsui N. , Tsuchido T. , Takano M. , Shibasaki I.
Published: March 2008

The viability of heat‐stressed cells of Escherichia coli was influenced by the temperature of incubation prior and subsequent to heat treatment. The effect of pre‐incubation temperature on the viability of heated cells was almost constant regardless of heating temperature in the range 48–54°C. The involvement of the change in fluidity of the membrane was suggested as a cause of the effects of pre‐incubation and post‐incubation. These phenomena were observed with other Gram negative and positive bacteria, and yeasts.
Investigations on cellulose biodegradation in activated sludge plants
Authors: Verachtert H. , Ramasamy K. , Meyers M. , Bevers J.
Published: March 2008

Cellulose is the major carbon substrate entering treatment plants for municipal waste waters. In the present investigation an attempt was made to study its degradation in activated sludge. Cellulolytic micro‐organisms were enumerated in different treatment plants and at one plant they were assessed after different steps over a period of about 1 year. The degradation of cellulose contained in Nylon bags suspended in the mixed liquor was also studied and the activities of cellulase components were assayed. Finally, the concentrations of cellulose and lignin in the suspended solids taken from different treatment steps were determined. The results showed that active cellulolysis occurred in activated sludge. The degradation was mainly bacterial, although no significant enrichment of such bacteria was found in the sludge floc. Cellulase activity, however, showed an increase. Experiments with the Nylon bag indicated that 60% of the weight of cotton wool was degraded in 4–5 weeks. It was concluded that about 60% (w/w) of the cellulose entering the system could be degraded by bacteria during aerobic treatment, while 50–60% of that present in the surplus activated sludge was degraded during anaerobic sludge digestion.
Glutamate as a differential nitrogen source for the characterization of acetylene‐reducing Rhizobium strains
Authors: Kaneshiro T. , Kurtzman M.A.
Published: March 2008

A majority (36 of 44) of Rhizobium japonicum strains tested reduced acetylene asymbiotically when grown on an agar medium containing 0.1% (w/v) L‐glutamate as a sole nitrogen (N) source. Glutamate as N source led to pinpoint colonies and uniform glutamine synthetase activity of three selected, slow‐growing acetylene‐reducing strains (R. japonicum L‐259 and 110 and a cowpea‐type Rhizobium 32H1). The three test strains were characterized further by antibiotic resistance, colony type, cellular morphology, and differential growth on different N sources. The evidence suggests that, in an agar medium, glutamate creates a growth condition leading to acetylene reduction activity, pinpoint colonies and pleomorphism.
Actinoplanetes in soil and on plant litter from freshwater habitats
Authors: Makkar N.S. , Cross T.
Published: March 2008

An isolation method for actinoplanetes is described which uses the ability of the sporangium to withstand desiccation and release motile spores when subsequently rehydrated. The desiccation stage reduces the number of associated Gram negative bacteria which cause problems when attempts are made to isolate species on agar plates from natural substrates. The method has enabled the isolation of actinoplanetes directly from soil and plant litter and indirectly from soil with the aid of baits such as pollen and hair. Actinoplanetes appear to be common in dry soils collected from arid areas and sand dune systems. They are normally present on leaves submerged for a time in rivers, streams and lakes and subsequently deposited in heaps on shores or as debris on overhanging vegetation. An actinomycete resembling the ‘spore‐dome’ organism recovered from leaves and twigs by Willoughby (1969) was frequently isolated during the course of these studies. Preliminary work suggests that different species can be recognized and could constitute a new genus within the family Streptomycetaceae.
A numerical taxonomic study of Pseudomonas strains from spoiled meat
Authors: Shaw B.G. , Latty Josephine B.
Published: March 2008

A numerical taxonomic study using 160 unit characters has been performed on 110 isolates of pseudomonads from aerobically spoiled beef and pork and on 13 named strains from the genus Pseudomonas. Four clusters of meat strains were detected at 87%S. Non‐fluorescent strains were contained in two closely related clusters (1 and 2) which were identified with P. fragi. Clusters 3 and 4 contained fluorescent strains which were distinct from P. fluorescens, P. putida and the other named strains examined. An identification scheme based on 11 carbon source tests is presented for the recognition of cluster members.
A note on milk clotting ability in the yeast genera Cryptococcus and Rhodotorula
Authors: Federici F.
Published: March 2008

One‐hundred and forty‐five yeast strains, 84 belonging to the genus Cryptococcus and 61 to the genus Rhodotorula, have been screened for their milk clotting ability. All the Rhodotorula and most of the Cryptococcus species showed a significant milk clotting ability. The results of the present study could possibly be of some taxonomic value and, furthermore, certain isolates seem interesting as producers of extracellular protease.
Development of a computer identification system for coliform strains
Authors: Gavini F. , Oger C. , Lefebvre B. , Izard D. , Leclerc H.
Published: March 2008

A computer identification system, previously described, was tested on 279 β‐galactosidase‐positive enterobacteria isolated from clinical material, and the results compared with API and Micro ID methods. The system was also applied to the identification of 564 strains isolated from drinking water samples. Faecal coliform species and also some new groups and species of aquatic and telluric origin characterized by numerical analysis and DNA‐DNA hybridization procedures could be identified. The performance of the computer identification system with bacterial isolates from food and water is discussed.
A simplified strategy for the identification of Gram negative fermenting rods using a desk‐top computer
Authors: Schindler J. , Idlbek J.
Published: March 2008

A total of 845 strains of Gram negative, fermenting rods isolated from humans were routinely identified using a desk‐top computer. A reduced matrix of 54 taxa x 29 tests was used for a multistep procedure. By an average number of 24 tests, 97–5% of strains reached an identification score of P < 0.9.
Pectolytic Clostridium spp. in soils and rhizospheres of carrot and other arable crops in east Scotland
Authors: Perry D.A.
Published: March 2008

Carrot root tissue discs rotted rapidly in anaerobic conditions after inoculation with soil from 40 different carrot fields and from ten fields of a mixed arable farm. Significant differences occurred in rotting potential between the soils and pectolytic Clostridium spp. were isolated from the rotted discs. Direct counts of pectolytic clostridia on selective pectate plates detected populations of 44–23.5 × 103 viable propagules/g dry soil in field soils. Significant increases in viable propagules were found in the rhizosphere soils of most carrot crops and in a range of other arable crops examined. The ratios of populations in the rhizospheres and surrounding soils varied between 1.8 and 8.2. Irrigating to excess and inter‐row cultivation of carrot crops did not consistently affect populations in soil or on roots.
Chemotaxonomy of the genus Capnocytophaga (Leadbetter, Holt & Socransky)
Authors: Collins M.D. , Shah H.N. , McKee A.S. , Kroppenstedt R.M.
Published: March 2008

The lipid and DNA base composition of Capnocytophaga ochracea, C. gingivalis, C. sputigena and some capnophilic clinical isolates were examined. The results of the study indicate that the genus Capnocytophaga (Leadbetter, Holt & Socransky) is a homogeneous taxon distinct from the genus Bacteroides.
Ecology of Vibrio species, including Vibrio cholerae, in natural waters of Kent, England
Authors: West P.A. , Lee J.V.
Published: March 2008

The distribution of Vibrio species in water from two sites in Kent was studied between 1978 and 1980. They were counted by a most probable number technique using alkaline peptone water for enrichment followed by plating onto thiosulphate citrate bile salt sucrose agar, or by direct plating of water onto the same agar. In a freshwater stream both upstream and downstream from a human sewage works outfall V. metschnikovii was the predominant Vibrio. Vibrio anguillarum was isolated sporadically. Non‐O1 serovars of V. cholerae occurred only twice. At the other site in a ditch containing static, brackish water, non‐O1 V. cholerae (highest number 400 cfu/ml) was observed as present only from May to November. Vibrio anguillarum was isolated throughout the sampling period. The presence of non‐O1 V. cholerae in both sites was not dependent on the input of human sewage. The hypothesis that non‐toxigenic V. cholerae can survive and multiply in water was tested in the ditch by the use of submersible chambers constructed of polycarbonate membranes and Plexiglass. The seasonal incidence of non‐O1 V. cholerae in the brackish water site could be explained by the multiplication of the organism when the water temperature exceeded 9°C. It was concluded that strains of V. cholerae that are unable to produce cholera toxin are indigenous to static brackish water environments and the possibility that this applies to toxigenic strains as well should be investigated.
Analysis of bacterial menaquinone mixtures by high performance liquid chromatography
Authors: Tamaoka J. , Katayama‐Fujimura Y. , Kuraishi H.
Published: March 2008

Menaquinone mixtures of microbial origin were separated according to the chain length and the degree of hydrogenation of the polyisoprenyl side‐chain by reversephase partition high performance liquid chromatography. Menaquinones can be measured easily and sensitively by the chromatographic system described here.
The microbial flora of smoked pork loin and frankfurter sausage stored in different gas atmospheres at 4°C
Authors: Blickstad E. , Molin G.
Published: March 2008

The development of the microflora of smoked pork loin and frankfurter sausage was followed during storage in vacuum, N2 and CO2 atmospheres at 4°C. The total aerobic count on the smoked pork loin reached 107 organisms/g after 37 d in vacuum, 43 d in N2 and 49 d in CO2. The corresponding value for the sausage was 77 d in vacuum, while the growth stopped at 6 times 104 organisms/g after 98 d in N2, and at 4 times 102 organisms/g after 48 d in CO2.

The predominant organisms on the fresh products were Bacillus spp., coryneform bacteria, Flavobacterium spp. and Pseudomonas spp.

At the end of the storage time the microflora on both products in the three gas atmospheres, consisted mainly of Lactobacillus spp. and two large groups of organisms that could not be identified as any described genus. Some of the unidentified strains could be classified as a Lactobacillus sp. after subsequent subculturing on laboratory media.

The numbers of Lactobacillus spp. at the end of storage decreased in the order, CO2 > N2 > vacuum. Lactobacillus viridescens generally constituted a substantial part of the Lactobacillus flora (5–72%). On the sausages two large uniform groups of unidentifiable homofermentative Lactobacillus spp. were also found.
Effect of fatty acid supplementation on the lipid composition of Mycobacterium smegmatis ATCC 607, grown at 27° and 37°C
Authors: Khuller G.K. , Taneja R. , Nath N.
Published: March 2008

Mycobacterium smegmatis ATCC 607 was grown at 27 and 37°C, with and without exogenous unsaturated fatty acids, viz. elaidic, oleic and palmitoleic acids, added to the growth medium. The total lipid content of M. smegmatis ATCC 607 was lower at 27°C, and with added oleic acid, when compared with the controls, but higher in presence of palmitoleic acid. At 37°C no significant differences were noted in the total lipid content. In general, the total lipid content was lower with all of the fatty acid supplementations at both 27 and 37°C. The phosphatidylethanolamine content was slightly higher at 27°C in the presence of elaidic or palmitoleic acid, but was markedly lower with oleic acid supplementation at 37°C. The cardiolipin content was lower in the presence of any of the fatty acids at 27°C, and higher in the medium supplemented with elaidic or oleic acid at 37°C. The unsaturated to saturated fatty acids ratio was higher with palmitoleic acid supplementation at 27°C, but remained unchanged in cells grown at 37°C. The modifications in mycobacterial lipids are a reflection of the organism's ability to adapt to changing growth conditions.
Fatty acid and lipid compositions of Conidiobolus
Authors: Miura Yoshiro , Nagai Tatsuo , Ishiyama Ikuo
Published: March 2008

The fatty acid composition of the total lipids from two Conidiobolus species was studied by gas—liquid chromatography. The major fatty acids of C. lamprauges were palmitic acid (C16:0), oleic acid (C18:1), linolenic acid (C18:3), and arachidonic acid (C20:4). For C. eurymitus, myristic acid (C14:0), C16:0, and linoleic acid (C18:2) were the most abundant acids. The fatty acid composition of C. eurymitus was quite different from that of the Conidiobolus species as mentioned in other reports. The lipid composition of the total lipids of C. lamprauges and C. eurymitus was also studied by thinchrography on quartz rods. Triglycerides and phospholipids were the major components in the two Conidiobolus species.
A microcomputer‐based information storage and retrieval system for the maintenance of records for a culture collection
Authors: Bryant T.N.
Published: March 2008

A microcomputer‐based system for the storage and retrieval of information on strains in a culture collection is described. The system was designed around commercially available software packages written for microcomputers. Two additional programs were written using the BASIC language to allow a catalogue of the culture collection to be printed in a specific format. The details of each strain in the collection were stored on a floppy disc. Details of new strains were added to this database and information relating to existing cultures was modified or, where necessary, deleted from the collection. The database can be searched to supply details of a particular culture or to identify those cultures which possess certain attributes. The records for the whole collection were sorted alphabetically by species name, and numerically by accession number, and a word‐processing package was used to print a catalogue of the culture collection.
An improved medium for the detection of Aspergillus flavus and A. parasiticus
Authors: Pitt J.I. , Hocking Ailsa D. , Glenn Diane R.
Published: March 2008

An effective selective medium for the enumeration of Aspergillus flavus and Aspergillus parasiticus has been developed by modification of Bothast and Fennell's Aspergillus Differential Medium. Results can be obtained with the new medium, Aspergillus flavus and parasiticus Agar (AFPA), after 42 h incubation at 30°C. The medium is thus suitable for use in quality control as a guide to the presence of A. flavus and, potentially, of aflatoxins. AFPA has been extensively tested on peanuts and soils. Results were reproducible and comparable with those on standard fungal enumeration media incubated for much longer periods. A very low percentage of false positives or negatives was found.
A note on the preparation and use of a selective differential medium for the isolation of Acinetobacter spp. from clinical sources
Authors: Holton J.
Published: March 2008

A selective, differential medium is reported for the isolation of Acinetobacter spp. With this medium it was found that not one of 30 people carried Acinetobacter spp. in their faeces, but 2 of 40 individuals carried it on their skin.
A note on a single tube technique for the Hugh and Leifson's oxidation‐fermentation test
Authors: Bruce J. , Davey G.M. , Drysdale E.M.
Published: March 2008

A method of conducting the oxidation‐fermentation (O/F) test in a single tube containing two layers of Hugh & Leifson's medium separated by a layer of vaspar is described.
Performance of a semi‐automated antibiotic susceptibility testing system (ABAC)
Authors: Lamp R.P.M. , Moulton R.P. , Mulders S.L.T.
Published: March 2008

The ABAC system for antibiotic susceptibility testing was compared with an agar diffusion method in 14960 tests, including 23 antibacterial agents. Identical breakpoints were used. Only 3% major discrepancies (M.d.; sensitive vs resistant) and 19% minor discrepancies (m.d.; intermediate vs sensitive or resistant) were noted. Major discrepancies were mainly found for methicillin (Staphylococcus aureus), netilmicin (Pseudomonas aeruginosa), chloramphenicol, sulphamethoxazole and tri‐methoprim (Proteus sp.) and were checked by quantitative susceptibility tests. These showed ABAC to be at fault in 41–47% of discrepancies, the diffusion test in 21–32% and 21–37% were intermediate. Half of the m.d. involved beta‐lactams, which is explained by too low breakpoints. Except for methicillin and netilmicin the overall results showed ABAC to be equal to the agar diffusion method. Technical faults, like leakage and incorrect filling of cups in the plastic rotors of ABAC, occurred in 14% of the rotors.
The intestinal microflora of farmed Dover sole (Solea solea) at different stages of fish development
Authors: Campbell A.C. , Buswell J.A.
Published: March 2008

The bacterial flora in the intestines of farmed Dover sole (Solea solea L.) was investigated at different stages of fish development in relation to different diets fed under farming conditions. The flora of water and diets were also analyzed. The dominant generic group isolated from all water samples examined was Pseudomonas Gp IV/Alcaligenes. The same generic group was dominant in homogenized pelagic larvae indicating a relationship between the microflora of those young fish and that of tank water. In older fish a steady increase in the percentage incidence of Vibrio/ anaerogenic Aeromonas was observed in the intestines as fish grew and diets changed. The Vibrio/anaerogenic Aeromonas group was dominant in Lumbricillus rivalis used as an intermediate diet and the increased incidence of this group in fish intestines occurred after fish were fed this diet. The composite pellet used for ongrowing carried a high percentage of Gram positive micro‐organisms and there was no relationship between the pellet microflora and that found in the fish intestines.
Bacillus spp. in the rumen ecosystem. Hemicellulose depolymerases and glycoside hydrolases of Bacillus spp. and rumen isolates grown under anaerobic conditions
Authors: Williams A.G. , Withers Susan E.
Published: March 2008

Bacillus spp. were isolated from the rumen contents of animals fed on hay. The bacilli were present in the vegetative form in the microbial populations of the liquid phase and in those associated with the particulate material in the digesta. Thirty‐six isolates were identified as strains of B. licheniformis (14), B. circulans (14), B. coagulans (2), B. laterosporus (3) and three isolates were facultative anaerobes that resembled B. pumilus. All were able to utilize isolated Lolium perenne hemicellulose B as a carbon source when grown aerobically or anaerobically at 39°C. A survey of 17 Bacillus species (24 strains including 5 rumen isolates) confirmed that enzymes capable of releasing reducing sugars from hemicelullosic polysaccharides were present in many anaerobically grown bacilli; in addition, the range and specific activities of 20 glycoside hydrolases were also monitored in these crude enzyme preparations. The presence and possible role of Bacillus spp. in the rumen digesta particle‐associated microbial population is discussed.
Sorbitol‐fermenting bifidobacteria as specific indicators of human faecal pollution
Authors: Mara D.D. , Oragui J.I.
Published: March 2008

Bifidobacteria were consistently present in the faeces of both man and pigs but only occasionally in the faeces of cattle and sheep, and they were not isolated from faecal samples from other animals; total counts of bifidobacteria were obtained by membrane filtration with YN‐17 medium, a modification of Resnick and Levin's YN‐6 medium. Mannitol‐fermenting strains of bifidobacteria were isolated from both human and animal faeces, but sorbitol‐fermenting strains were obtained only from human samples. These sorbitol‐fermenting strains were identified as either Bifidobacterium adolescentis or B. breve and their numbers were obtained by membrane filtration on Human Bifid Sorbitol agar (HBSA). Sorbitol‐fermenting bifidobacteria are specific indicators of human faecal pollution of waters and wastewaters.
A note on the effects of oxygen on hydrogen production by the rumen protozoon Dasytricha ruminantium Schuberg
Authors: Yarlett N. , Scott R.I. , Williams A.G. , Lloyd D.
Published: March 2008

Hydrogen production by the rumen protozoon, Dasytricha ruminantium was reversibly inhibited at O2 tensions < 2.8 μmol/1. At higher O2 concentrations irreversible inactivation of the hydrogenase system was observed. In the rumen, H2 generation is likely to be determined by O2 concentration since the physiological levels of O2 in the rumen are in the range 0–1.5 μmol/1.
A proposed life cycle for the Reiter treponeme
Authors: Al‐Qudah A.A. , Mostratos Ann , Quesnel L.B.
Published: March 2008

Direct microscopical observations of single developing cysts in sealed slide microcultures prepared from 5‐days‐old tube cultures of the Reiter treponeme revealed two distinct phases in the life cycle. In one phase transverse fission was the main method of multiplication while in a second phase, occurring when conditions in the medium became unfavourable for propagation, cysts developed. These could release large numbers of actively motile treponemes when returned to optimum growth conditions. These observations, together with results of the dilution method for the calculation of the Most Probable Number and the absence of a response in treponemes killed by high temperature (45°C) or abnormal pH (10), showed that the cysts were viable and a mode of propagation for the Reiter treponeme.
The rapid estimation of microbial contamination of raw meat by measurement of adenosine triphosphate (ATP)
Authors: Stannard C.J. , Wood J.M.
Published: March 2008

Bacteria were separated from raw meat homogenate by a simple three‐stage process. Centrifugation (10 s at 2000 g) removed coarse particles; stirring with the cation exchange resin Bio‐Rex 70 removed smaller particles and filtration through 0.22 μm membranes removed soluble materials. By this process 70—80% of the microbial populations of meat homogenates were consistently isolated on the filters. A linear relationship was found between log10 microbial ATP and log10 colony count of meat over the range 105—109 cfu/g. The value of ATP/cfu for meat samples was within the range previously reported for pure cultures. These data indicated that ATP extracted from the filters originated from bacteria in the meat samples. Several samples can be analysed simultaneously in an elapsed time of 20—25 min. The variability associated with estimates of both colony counts and ATP levels has been determined.
Inhibition of the growth of acid tolerant yeasts by acetate, lactate and propionate and their synergistic mixtures
Authors: Moon Nancy J.
Published: March 2008

Saccharomyces uvarum, Geotrichum candidum, Endomycopsis burtonii and Hansemula canadensis have been isolated from deteriorated silages and/or spoiled lactic acid fermented foods. All yeasts could grow in relatively high (100 mmol/l) concentrations of acetate or lactate in Wickerham's assimilation broth but were inhibited by increasing concentrations of these acids. Propionate was much more inhibitory than acetate or lactate. Growth rate, but not final cell yield, was adversely affected by increasing concentrations of these acids. The three acids used in combination were synergistically inhibitory to H. canadensis and G. candidum. Saccharomyces uvarum was inhibited by synergistic mixtures of acetate/propionate. Endomycopsis burtonii and H. canadensis were inhibited by synergistic mixtures of acetate/lactate, acetate/propionate and lactate/propionate. Lactate and propionate had a synergistic inhibitory effect on G. candidum. The mechanism of inhibition of growth of S. uvarum by acetate and propionate was further investigated. Acetate and propionate each caused a reduction in cellular efficiency (Y, μg cells/μmole glucose consumed). Mixtures caused a drastic reduction in growth rate and Y. These results suggest that the cells may expend energy in reducing intracellular concentrations of acetate while propionate probably acts in a different manner.
Factors affecting lipase production in Syncephalastrum racemosum
Authors: Chopra A.K. , Chander H.
Published: March 2008

Syncephalastrum racemosum grown as a static culture showed maximum lipase production at 30°C in 2d at pH 8.0. When the medium was supplemented with fructose, maximum production of lipase per unit of growth was achieved, followed by raffinose, sucrose, ribose, galactose, maltose, lactose, mannitol and glucose. Amongst the nitrogen sources tested, corn steep liquor at 8% (v/v) produced maximum enzyme; there was evidence of catabolite repression by glucose when groundnut protein, soybean meal, milk casein or wheat bran were the sources of nitrogen. Calcium, potassium and sodium citrates, each at 0.1% (w/v), increased the yield of lipase.
Differentiation of Salmonella typhi using resistotyping
Authors: Somerville P.C. , Nhlapo W.M. , Alberts M.
Published: March 2008

The potential value of resistotyping in the investigation of strain differences is illustrated by its application to Salmonella typhi. The method, although very demanding and prone to technical difficulties, is capable of yielding information about the identity of strains. In its present form the technique was shown to be able to characterize strains in such a manner that available epidemiological information was confirmed.
The vitamin requirements ofStaphylococcus cohnii
Authors: Cove J.H. , Kearney J.N. , Holland K.T. , Cunliffe W.J.
Published: March 2008

The vitamin requirements of 66 strains ofStaphylococcus cohniifrom various sources were determined using solidified and liquid chemically defined media. All the strains tested required nicotinic acid and thiamine. Biotin was either growth stimulatory or essential for 34 strains. Pantothenic acid was required by 21 of the 30 strains of known human origin but was not required by any of the 24 strains of murine origin. There was an association amongStaph. cohniistrains to grow in the absence of pantothenic acid and biotin and the ability to produce acid from lactose and the possession of phosphatase activity (20. strains). The majority of strains requiring pantothenic acid and biotin were unable to ferment lactose and did not possess phosphatase activity (22 strains).