bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences in adhesiveness among type 1 fimbriate strains of Enterobacteriaceae revealed by an in vitro HEp2 cell adhesion model
Authors: Old D. C. , Roy A. I. , Tavendale Anne
Published: March 2008

Ten type 1 fimbriate strains of Enterobacteriaceae were examined in an in vitro adhesion assay with HEp2 epithelial cells. The range of HEp2 cell adhesiveness, which was characteristic for each strain, was affected by motility, type 1 fimbriation and production of mannose sensitive haemagglutinin. Nevertheless, not all type 1 fimbriate strains adhered well in this model. The findings are discussed with regard to the possibility that different type 1 fimbriate enterobacteria, though all are mannose sensitive, recognize different mannose‐containing receptors present or available on the surfaces of the HEp2 cells.
Decrease in adherence of bacteria and yeasts to human mucosal epithelial cells by noxythiolin in vitro
Authors: Gorman S. P. , Mccafferty D. F. , Woolfson A. D. , Anderson L.
Published: March 2008

Adherence of buccal and vaginal isolates of Candida albicans to buccal epithelial cells and the adherence of urine isolates of Escherichia coli and Staphylococcus saprophyticus to uroepithelial cells was quantified by light microscopy. The antimicrobial agent noxythiolin reduced the adherence of these micro‐organisms in both exponential and stationary growth phases. Adherence of both the blastospore and pseudohyphal forms of C. albicans was reduced. Treatment of epithelial cells and/or micro‐organisms with noxythiolin resulted in decreased adherence. No anti‐adherence effect was observed with formaldehyde and N‐methylthiourea, the degradative products of noxythiolin.
The in vitro metabolism of free and bacterially‐bound 2,2'‐diaminopimelic acid by rumen micro‐organisms
Authors: Masson Hilary A. , Ling J. R.
Published: March 2008

Protozoa and bacteria were isolated from the rumen of a sheep given a concentrate and hay diet and were incubated separately with either free 2,2'‐diaminopimelic acid (A2pm) as [G‐3H]A2pm or bacterially‐bound A2pm in the form of [G‐3H]A2pm‐labelled Bacillus megaterium GW1. Lysine was the only radiolabelled metabolite produced in pellet and supernatant fluid when ciliates were incubated with 0·1 mmol/l free [G‐3H]A2pm; pipecolate was an additional product when 1·0 and 8·0 mmol/l A2pm were used. As well as incorporating A2pm, rumen bacteria decarboxylated it and produced a further three unidentified metabolites in the supernatant fluids. Protozoa rapidly engulfed and digested [G‐3H]A2pm‐labelled B. megaterium GW1. Radioactive A2pm and lysine were present in the protozoal pellets. A2pm, lysine and three other radiolabelled compounds were excreted into the supernatant fluids; the major product, designated G, appeared to be a series of A2pm‐containing peptides and derivatives. When rumen bacterial cells were incubated with [G‐3H]A2pm‐labelled B. megaterium GW1 they accumulated A2pm and lysine. Only A2pm and G were detected in bacterial supernatant fluids. The significance of these results to the use of A2pm as a marker of bacterial outflow from the rumen is assessed.
DNA‐DNA homology, physiological characteristics and distribution of lactic acid bacteria isolated from maize silage
Authors: Dellaglio F. , Torriani Sandra
Published: March 2008

Lactic acid bacteria represent a dynamic bacterial group in maize silages. their establishment, variations and characterization have been studied by investigating 22 samples taken at different times during the ensilage process. After a preliminary screening based on physiological characteristics, 100 of 229 strains isolated were chosen for further taxonomic investigation. Twenty‐nine strains of homo‐fermentative lactobacilli were identified as Lactobacillus plantarum, L. casei and L. coryniformis subsp. coryniformis; 24 heterofermentative strains were allotted to the species L. buchneri, L. brevis, L. fermentum and Leuconostoc paramesenteroides; 22 coccal strains were assigned to Pediococcus pentosaceus and P. acidilactici and 25 coccal strains were identified as Enterococcus faecium, Streptococcus lactis and Strep. bovis. A few strains remained unidentified.
Characteristics of staphylococci isolated from man, poultry and some other animals
Authors: Adegoke G. O.
Published: March 2008

Of 281 strains of staphylococci isolated from man and animals 36 (12–8%) were coagulase‐positive and 245 (87–2%) were coagulase‐negative. Staphylococcus aureus and Staph. intermedius were the commonest coagulase‐positive staphylococci isolated from the hosts examined. Of the 20 strains that remained unclassifiable, 14 were isolated from sheep and goats.
A note on ultra‐violet red fluorescence of anaerobic bacteria in vitro
Authors: Brazier J. S.
Published: March 2008

Anaerobes other than the Bacteroides melaninogenicus group isolated from clinical material produce an ultra‐violet red fluorescence when grown under certain conditions in vitro. These organisms include other members of the genus Bacteroides as well as strains of some species of Clostridium, Bifidobacterium and Actinomyces. The major fluorescent pigment was identified as protoporphyrin IX. Factors necessary for the production of fluorescence are the presence of blood or haem and a fermentable carbohydrate during growth on a solid medium. Fluorescence intensity was related to the concentration of blood and fermentable carbohydrate present but was independant of inoculum size. Certain commercially available blood agar bases designed specifically for the isolation of fastidious anaerobes from clinical material which contain added carbohydrate were shown to induce fluorescence in certain organisms. This may lead to the misidentification of some anaerobes as B. melaninogenicus.
Pyridine nucleotides and redox state regulation of aflatoxin biosynthesis in Aspergillus parasiticus NRRL 3240
Authors: Bhatnagar Raj K. , Ahmad S. , Mukerji K. G. , Subramanian T. A. V.
Published: March 2008

In vivo regulation of lipid and aflatoxin biosynthesis by pyridine nucleotides and their derived functions was studied in Aspergillus parasiticus NRRL 3240. Aflatoxins, total lipids and pyridine nucleotide content were estimated under different growth conditions. Aflatoxin formation was highest in cultures grown in sucroselow salts medium followed by asparagine‐ and zinc‐deficient media. The lipid content of the cultures followed an inverse pattern. The levels of oxidized nucleotides decreased with age under all culture conditions employed. Concentrations of NADPH peaked before the onset of aflatoxin biosynthesis. For each medium used, the estimated catabolite reduction charge was constant at all stages of growth whereas the anabolic reduction charge varied. A direct relationship between the level of extracellular ammonium ions and anabolic reduction charge was established. A high anabolic reduction charge was associated with increased lipid biosynthesis rather than aflatoxin biosynthesis.
Use of the direct epifluorescent filter technique for the enumeration of yeasts
Authors: Rodrigues Ubaldina M. , Kroll R. G.
Published: March 2008

The ability of the direct epifluorescent filter technique (DEFT) to enumerate the viable numbers of various species of yeasts was evaluated. A DEFT count could be made in less than 10 min and the DEFT counts of non‐heat‐treated samples agreed well with plate counts. The DEFT was unsuitable for the enumeration of yeasts in heat‐treated samples because non‐viable cells fluoresced orange. A double staining technique using Janus Green B and acridine orange was developed to overcome this problem. The modified DEFT enabled viable and non‐viable yeasts to be differentiated in heat‐treated samples of pure cultures and improved the relationship between the DEFT count and plate count. The method proved to be of little value, however, for use with beverage products because of unreliable staining patterns.
A note on pH gradient plates for fungal growth studies
Authors: Sacks L. E. , King A. D. , Schade J. E.
Published: March 2008

A pH gradient agar plate with surface pH ranging from about 3.2 to 7.1 was easily prepared. The gradient was sufficiently stable to permit different growth characteristics among various fungal species at different pH values to be distinguished. The pH effects on growth rate, conidiogenesis, pigment and toxin formation were consistent with the results obtained by other workers who used more laborious methods.
Properties of a cellulolytic Sporolactobacillus and some non‐sporing cellulolytic rods, presumptive clostridia, from an anaerobic digester
Authors: Sharma V. K. , Hobson P. N.
Published: March 2008

Anaerobic digesters contain a wide variety of anaerobic cellulolytic bacteria. Many of these are sporing rods. Some isolates from a mesophilic cattle waste anaerobic digester were classified as Sporolactobacillus spp. A further group of bacteria could not be induced to sporulate. In some respects they resembled Eubacterium, but considering all the properties it is suggested that they should be classified as a species of Clostridium.
Use of conductance methods to predict bacterial counts in fish
Authors: Ogden I. D.
Published: March 2008

Conductance methods to measure bacterial growth are more rapid than conventional methods for assessing the load of spoilage bacteria in fish. With the correct choice of medium, an estimate of the count can be obtained within 24 h which shows a very good correlation with the conventional methods. Moreover, the conductance changes correlate better with counts of those organisms thought to be responsible for spoilage. The Malthus conductance instrument provides an automated system capable of the simultaneous monitoring of 128 different samples, resulting in considerable savings of time and effort over traditional plate counting techniques.
The effect of different cellulosic growth substrates and pH on the production of cellulolytic enzymes by Trichoderma reesei
Authors: Knapp J. S. , Legg M.
Published: March 2008

The effect of different cellulosic growth substrates on the production of cellulolytic enzymes by Trichoderma reesei was investigated. It was observed that growth on Avicel, Solka Floc and wheat straw produced different pH/time profiles in cultures. Over a range of controlled pH it was demonstrated that the production of cellulolytic and xylanolytic activity by T. reesei is dependent on culture pH and the type of growth substrate. The effect of pH on enzyme production varies with the nature of the growth substrate. Furthermore, it was shown that the optimum culture pH and growth substrate for the production of enzyme preparations for the extensive saccharification of cellulosic materials depends on the type of material to be saccharified.
Purification and characterization of a streptomycete collagenase
Authors: Chakraborty R. , Chandra A. L.
Published: March 2008

A soil streptomycete designated as Streptomyces sp. A8 produced an extracellular collagen hydrolysing enzyme that appeared to be ‘true collagenase’as it degraded native collagen under physiological conditions and cleaved the synthetic hexapeptide 4‐phenylazobenzyloxycarbonyl‐L‐prolyl‐L‐leucyl‐glycyl‐L‐prolyl‐D‐arginine into two tripeptides. The enzyme was purified by diethyl aminoethyl cellulose chromatography and Sephadex G‐150 gel filtration. The purified enzyme had an apparent molecular weight of about 75000 by SDS‐polyacrylamide gel electrophoresis. Treatment with lithium chloride did not dissociate it into subunits. A strong inhibition was observed with chelating agents such as α‐α‐dipyridyl and 8‐hydroxyquinoline. Ethylene diamine tetracetate completely inhibited the enzyme activity. Among the cations tested only Ca2 + and Mg2 + enhanced the collagenase activity. Heavy metal ions like Pb2 +, Ag+, Cu2 + and Zn2 + strongly inhibited the enzyme. The EDTA inhibition could be reversed with Ca2 +. Cysteine and reduced glutathione caused significant reduction in enzyme activity. Parachloromercuribenzoate and iodoacetamide had no effect on the collagenase. Amino acid analysis revealed the absence of cysteine and tyrosine. Many of the properties were the same as collagenases of Clostridium histolyticum and Vibrio alginolyticus.
The action of various venoms on Escherichia coli
Authors: Stocker Jane F. , Traynor J. R.
Published: March 2008

The antibacterial activity of honeybee venom (Apis mellifera), three snake venoms (Naja naja sputatrix, Vipera russellii and Crotalus adamanteus) and the polypeptide melittin was investigated against Escherichia coli. Minimum inhibitory concentration values, cell lysis and alterations in cell permeability were determined and action against E. coli was in the order: A. mellifera venom > melittin > N. naja sputatrix venom ≫V. russellii venom > C. adamanteus venom. Cellular damage by A. mellifera and N. naja sputatrix venoms was evident in electron micrographs.
Numerical classification of species of Vibrio and related genera
Authors: Bryant T. N. , Lee J. V. , West P. A. , Colwell R. R.
Published: March 2008

Data from 1091 strains of the family Vibrionaceae collected in five different studies have been merged into a single data matrix and analysed in a taxonomic study. A set of 142 characters was selected to compare these data. Seventy‐nine characters were common to all studies, but data for the other 63 characters were incomplete. Cultures of 90 strains, examined in more than one of the original studies, were used to estimate test error and inter‐study variability. The data from these replicate strains also allowed the problem of merging data from different studies to be assessed. Taxonomic resemblance was estimated on the basis of 111 characters using the SSM coefficient and UPGMA clustering. A taxonomic analysis based on 999 strains, which included most of the major species of the family Vibrionaceae, gave 59 clusters and 44 unclustered strains. A table of properties of these phenons was produced. The results showed that data obtained from studies carried out at different times and in different locations, but using standard techniques, could be combined and used to provide useful taxonomic information.
Fate of salmonellas and competing flora in meat sample enrichments in buffered peptone water and in Muller‐Kauffmann's tetrathionate medium
Authors: Beckers H. J. , Heide J. V. D. , Fenigsen‐Narucka U. , Peters R.
Published: March 2008

Studies have been carried out in which growth patterns of a Salmonella sp. and competing micro‐organisms, especially other Enterobacteriaceae, were followed during pre‐enrichment in buffered peptone water (BPw) and subsequent selective enrichment in tetrathionate broth (TBB). Pre‐enrichment cultures were inoculated with minced meat and three reference samples containing nalidixic acid‐resistant salmonellas. Irrespective of their initial numbers in BPw, Enterobacteriaceae increased to 108/ml or more. During incubation in TBB at 43C, numbers of lactose‐positive Enterobacteriaceae decreased in most enrichments which resulted in a positive salmonella isolation, but remained constant in the majority of those that did not. Levels of lactose‐negative Enterobacteriaceae did not decrease in most salmonella‐positive tests, but did so in half of the salmonella‐negative ones. In the salmonella‐positive tests the numbers of salmonellas had increased to 103–107/ml in BPw and after transfer to TBB slowly reached 104/ml or more. In all cases the numbers of salmonellas exceeded those of the competing flora on brilliant green agar (BGA). In the salmonella‐negative tests the numbers of salmonellas had increased less in BPw and decreased in most of the TBB enrichments. In none of these negative tests did the numbers of salmonellas exceed those of the competing flora on BGA. Escherichia coli dominated in most of the salmonella‐negative tests. The results suggest more influence of lactose‐positive than lactose‐negative Enterobacteriaceae on the detection of salmonellas. The effect of competing microorganisms seems to depend not only upon their initial numbers, but also upon the types that can interact with salmonellas during selective enrichment.
Microbial film formation: dental plaque deposition on acrylic tiles using continuous culture techniques
Authors: Keevil C. W. , Bradshaw D. J. , Dowsett A. B. , Feary T. W.
Published: March 2008

A chemostat system has been developed to model the attachment of oral bacteria, and the subsequent development of plaque film, to acrylic surfaces immersed in steady state cultures. Plaque was removed from the teeth and gingival margin of volunteers who refrained from oral hygiene for at least 72 h. Samples were pooled and inoculated into a complex growth medium maintained at 37C. Glucose‐limited continuous culture was established at a dilution rate of 005/h and at pH 70. Microbiological analysis of the culture indicated that a complex community of oral bacteria was established, typical of that found in dental plaque. Acrylic tiles were immersed in the fermenter through a modified fermenter head and incubated therein for up to 21 d. Scanning electron microscopy showed that either side of the tiles contained a rough and a smooth surface and these initially favoured the attachment of fusiform bacteria, particularly on the rough surface. Cocci attached to those surfaces which were not heavily colonized by the fusiforms and eventually grew into and on the colonial sheets of the fusiforms.
Presumptive diagnosis of pulmonary nocardiosis: value of sputum microscopy
Authors: Osoagbaka O. U. , Njoku‐Obi A. N. U.
Published: March 2008

Three hundred samples of sputum from patients suffering from various forms of pulmonary disorders were homogenized by pancreatic digestion, examined microscopically and cultured on brain heart infusion agar, trypticase soy agar, in brain heart infusion broth, trypticase soy broth and McClung's carbon‐free broth. Several elements of varying morphological forms, believed to be from aerobic actinomycetes or nocardias, were observed in 16 cases. Six strains of Nocardia asteroides, one N. brasiliensis, eight of Rhodococcus species and one Micromonospora were isolated and studied at various stages of growth. Several nocardial and rhodococcal elements closely resembling those observed in the Gram‐stained sputa were found. It is suggested that some of those in the sputum were from nocardias and that their appearance in sputum, as seen from the Gram‐stained slide, when combined with clinical symptoms can serve for a presumptive diagnosis of pulmonary nocardiosis pending a more definitive identification by a specialized laboratory.
The susceptibility of the moderate halophile Vibrio costicola to heavy metals
Authors: Garcia M. T. , Nieto J. J. , Ventosa A. , Ruiz‐Berraquero F.
Published: March 2008

Fifty‐eight strains of the moderate halophile Vibrio costicola, including both culture collection strains and freshly isolated strains from solar salterns, were examined for their susceptibility to 10 heavy metal ions by using an agar dilution technique. All strains were sensitive to cadmium, copper, silver, zinc and mercury. This latter ion showed the highest activity even at 0·05 mmol/1 metal concentration. On the other hand, all strains were similarly tolerant to lead, and a great proportion of them were also tolerant to nickel (91%) and chromium (88%). Only 44% and 14% of them showed tolerance to arsenate and cobalt, respectively. The majority of strains (96·4%) were multiply metal‐tolerant, with three different metal ion tolerances as the major pattern.
A new scheme for phage typing Salmonella bareilly and characterization of typing phages
Authors: Jayasheela M. , Singh G. , Sharma N. C. , Saxena S. N.
Published: March 2008

A new phage typing scheme using wild bacteriophages isolated from sewage for phage typing Salmonella bareilly is described. Six hundred and thirty‐seven strains of Salm. bareilly could be separated into 11 different phage types using five wild phages. Overall typability was 94˙5%. These phages belonged to two different morphotypes, A1 and B1, and showed varying host range.
A bioserogroup of marine vibrios possessing somatic antigen factors in common with Vibrio cholerae O1
Authors: Shimada Toshio , Sakazaki Riichi , Oue Masakazu
Published: March 2008

A bioserogroup of halophilic vibrios, tentatively labelled bioserogroup 1875, strongly agglutinated by O1 antiserum of Vibrio cholerae is described. Cross‐agglutination and agglutinin‐absorption tests showed that these vibrios had antigens identical with the Ogawa and Inaba factors of V. cholerae O1, although they possessed their own specific antigen distinctive from the A factor that is the specific major antigen of the latter species. In addition, quantitative antigen variation similar to that of the Ogawa‐to‐Inaba type with V. cholerae O1 was recognized in this halophilic group. They were isolated from estuarine water and are considered to inhabit coastal aquatic environments. Phenotypically, however, this group is not identifiable with any of the species already recognized in the genus Vibrio.
Evolution of bacterial flora from a subterranean saline well by graduated salinity changes in enrichment media
Authors: Moral Ana del , Quesada Emilia , Bejar Victoria , Ramos‐Cormenzana A.
Published: March 2008

The bacterial flora of samples taken from a subterranean saline well was enriched (1) by periodic salinity increase and (2) by periodic salinity decrease, both at 25° and 35°C. During the enrichment process, bacterial flora, including halotolerant, marine, moderately and extremely halophilic bacteria, were enumerated. Results were similar at both temperatures. Marine bacteria and moderately halophilic microorganisms were the most favoured groups, predominating between 3 and 30% (w/v) salt content; extremely halophilic bacteria also appeared when salinity reached 30% (w/v) and halotolerant bacteria were poorly represented. The taxonomic distribution of 125 selected strains, chosen at random from counting media, was essentially similar to those from other hypersaline environments.
Factors influencing deactivation of yeast cells exposed to ethanol
Authors: Jones R. P.
Published: March 2008

The lyotropic series discovered in 1888 by Hofmeister describes the effect of solutes on the structure and physical chemistry of the aqueous phase. Chaotropic members of the lyotropic series destructure the aqueous phase while antichaotropic solutes act to enhance the structuredness of the aqueous phase. This alteration of the aqueous phase affects the physical structure or physicochemical state of any other phase exposed to the aqueous phase, such as the plasma membrane of any cell. Solute lyotropy is therefore, via its ability to alter the physicochemical state of the plasma membrane, able to modify the processes of yeast cell deactivation (i.e. the processes leading to loss of ability to replicate and to eventual cell death) in the presence of toxic solutes such as ethanol. In this study the effect of a variety of salts and non‐ionic solutes upon cell deactivation in the presence of 16% w/v ethanol is explained in terms of the lyotropic series. Chaotropic salts protect against ethanol‐induced deactivation and antichaotropic salts enhance the rate of this process. It is proposed that the mechanism by which chaotropic solutes exert their protective effect involves a reduction in the activity coefficient of the ethanol, thereby reducing the concentration of ethanol within the plasma membrane.
Comparative traits of Lactobacillus brevis, Lact. fructivorans and Leuconostoc oenos immobilized cells for the control of malo‐lactic fermentation in wine
Authors: Crapisi A. , Spettoli P. , Nuti M. P. , Zamorani A.
Published: March 2008

Decarboxylation of L‐malic to L‐lactic acid by heterolactic bacteria and formation of secondary products in table wine were studied using immobilized cells of Lactobacillus brevis, Lact. fructivorans and two strains of Leuconostoc oenos in a continuous flow bioreactor. The conversion ratios were 51.2–53.9%, while the decreases in malic and titratable acidity were equivalent to 62.1–74.7% and 16.4–27.3%, respectively. Upon completion of malo‐lactic fermentation, pH increased from 3.15 to 3.28–3.35. The conversion ratio and bioreactor efficiency differed according to the strain tested. Gel beads, prepared with cells immobilized in 2% K‐carrageenan in the presence of 5% bentonite silica, contained up to 7–8 × 1010 cfu/g; the concentration of viable cells was relatively stable over 24–48 h bioreactor operation when Lact. brevis was used and decreased in all other cases. The formation of secondary products affecting wine sensory properties, particularly volatile acids and aromatic compounds, was strain‐dependent.
Use of the direct epifluorescent filter technique for the enumeration of bacterial spores
Authors: Kelly Alison F. , Kroll R. G.
Published: March 2008

Heat treatment at 80°C for 10 min effectively destroyed all vegetative cells (except for Gram‐positive cocci) and made easier the counting of bacterial spores, which stained orange, green or rarely transparent/black with a dull green halo, in the direct epifluorescent filter technique. The numbers of both orange‐ or green‐staining spores were lower than the plate count. A variety of physiological conditions were used to investigate the relationship of the different staining patterns with germination status. It was concluded that orange‐staining spores had germinated and their number agreed with the plate count after incubation in yeast glucose broth at 30°C for 4 h. This observation was unreliable, however, but it was found that a total spore count in the DEFT gave a good agreement with the plate count.
Effects of Freon‐113 on the survival of bacteria
Authors: Sousa S. , Akkara J. A. , Kaplan D. L.
Published: March 2008

An initial investigation was made of the bactericidal and sporicidal activity of the dry cleaning solvent Freon‐113 (1,1,2‐trichlorotrifluoroethane) under various conditions. Representative bacterial strains selected for this study were Escherichia coli (ATCC 11229), Staphylococcus aureus (ATCC 6538) and spores of Bacillus globigii (Bacillus subtilis var. niger). Various conditions were studied, including temperature, moisture, detergents and organic load. The results of this study indicate that there is the potential for survival of significant levels of micro‐organisms in Freon‐113 within the conditions evaluated. However, the bactericidal efficiency of this solvent increases significantly against vegetative forms at elevated temperature and, to a greater extent, upon the addition of detergents. Organic material present in the form of soiled fabric was observed to depress this efficacy whereas bacterial spores were virtually unaffected under all conditions evaluated.
A note on the microbiology of retail packs of prepared salad vegetables
Authors: Brocklehurst T.F. , Zaman‐Wong C.M. , Lund Barbara M.
Published: March 2008

Retail packs of mixed, prepared salad vegetables from two different manufacturers were stored at 7°C until the end of storage‐life (sell‐by date plus 1 d), when the microbial flora was examined. The quality of the salads was acceptable at the end of storage‐life. The oxygen concentrations in packs were lower, and the carbon dioxide concentrations were higher, than those in air. High numbers of bacteria were present, with Pseudomonas spp. and Enterobacter agglomerans predominating in packs of both salads, together with lactic acid bacteria in one of the salads. Significant numbers of pectolytic bacteria including Pseudomonas spp. and Erwinia carotovora were detected. Despite the presence of high numbers of coliform bacteria, Escherichia coli was not detected in batches of one salad, and was detected in relatively low numbers in batches of the other. Yersinia spp., predominantly environmental strains of Yersinia enterocolitica, were isolated by enrichment from all samples tested; Staphylococcus aureus and enterococci were not detected.
Production of wine from mango (Magnifera indica L.) using Saccharomyces and Schizosaccharomyces species isolated from palm wine
Authors: Obisanya M. O. , Aina J. O. , Oguntimein G. B.
Published: March 2008

Juice extracted from pulp of the mature ripe tropical fruit, mango (Magnifera indica L.), containing 15.9% soluble solids, was fermented with four strains of yeast isolated from palm wine. Two of the strains belonged to the genus Schizosaccharomyces (T1 and T2) while the other two were Saccharomyces (B2 and M1). The two strains of Schizosaccharomyces were found to be suitable for the production of sweet, table mango wine with alcohol contents of 8.0 and 9.0% for T1 and T2, respectively. The two strains of Saccharomyces were found suitable for the production of dry mango fruit wines containing 10.0% alcohol.
Interactions between rumen amylolytic and lactate‐utilizing bacteria in growth on starch
Authors: Maroune M. , Bartos S.
Published: March 2008

The growth and metabolism of the rumen amylolytic bacteria Streptococcus bovis, Butyrivibrio fibrisolvens and Bacteroides ruminicola, growing in pure cultures and co‐cultures with the rumen lactilytic bacteria Megasphera elsdenii and Veillonella alcalescens were followed. The interaction of amylolytic bacteria with V. alcalescens represents a simple food chain. The interaction with M. elsdenii is more complex, since there is a simultaneous competition for products of the starch degradation.
Inhibitory activity of antibiotic‐producing marine bacteria against fish pathogens
Authors: DOPAZO C.P. , LEMOS M.L. , Lodeiros C. , Bolinches J. , Barja J.L. , Toranzo Alicia E.
Published: March 2008

The activity of antibiotic‐producing marine bacteria was assayed against bacterial fish pathogens belonging to the genera Vibrio, Aeromonas, Pasteurella, Edwardsiella, Yersinia and Pseudomonas with the aim of evaluating the possible use of these marine strains for controlling epizootics in aquaculture. Inhibition tests on solid medium showed that, in general, the majority of fish bacteria were strongly sensitive to the marine bacteria. Only two strains (Edwardsiella tarda and Pseudomonas aeruginosa), were resistant to all the antibiotic‐producing strains. The results of antagonism assays in sea water, however, varied according to the fish pathogens examined. Experiments conducted using cell‐free supernatant fluids of marine bacteria demonstrated the involvement of antibiotic substances in the inhibition of fish pathogens.
Occurrence of sulphate‐reducing bacteria in human faeces and the relationship of dissimilatory sulphate reduction to methanogenesis in the large gut
Authors: Gibson G.R. , Macfarlane G.T. , Cummings J.H.
Published: March 2008

Sulphate‐reducing bacteria (SRB) were enumerated in 40 faecal samples obtained from two different human populations in the United Kingdom and rural South Africa. Species able to metabolize acetate, lactate, propionate, butyrate, H2/CO2, succinate, pyruvate, valerate, ethanol and a glutamate/serine/alanine mixture were found in faeces from both populations. Although a variety of nutritionally and morphologically distinct species of SRB belonging to the genera Desulfotomaculum, Desulfobacter, Desulfomonas and Desulfobulbus were identified, Desulfovibrio types always predominated. Significant numbers of SRB were present only in faecal samples from subjects whose breath methane excretion was low or undetectable. Reduced or absent methanogenesis in the presence of SRB was confirmed in fermentation studies with faecal slurrries. Fourteen of 20 (70%) British faecal samples contained SRB and the remainder produced methane. The reverse was the case with 20 rural black South Africans, where only three (15%) of the samples had significant levels of SRB; the remaining 85% produced methane. These results suggest that to a large extent, dissimilatory sulphate reduction and methanogenesis are mutually exclusive in the human large gut.
Utilization of glucose, fructose and malic acid by malolactic bacteria: effect of ethanol and formation of mannitol and volatile acids
Authors: TRACEY R.P , ROOYEN T.J. VAN
Published: March 2008

Five lactic acid bacteria capable of carrying out the malolactic fermentation were studied at 15°C and 25°C. Results indicated that at 15°C hardly any glucose, fructose and l‐malic acid was utilized over a 9d period. After 9d at 25°C very little glucose and fructose and most (if not all) of the l‐malic acid was degraded. The addition of ethanol markedly affected the l‐malic acid utilization by the four Leuconostoc oenos strains at 25°C. Large differences in their ability to convert l‐malic acid were found amongst the four strains in media containing 5% and 10%(v/v) ethanol.
Differences in aerosol survival between pathogenic and non‐pathogenic strains of Legionella pneumophila serogroup 1
Authors: Dennis P.J. , Lee J.V.
Published: March 2008

A strain of Legionella pneumophila serogroup 1 known to be virulent for guinea‐pigs was found to be least stable at a relative humidity (r.h.) of 60% when stored as a small particle aerosol. Three L. pneumophila serogroup 1 strains of different virulence for guinea‐pigs were then tested at a r.h. of 60% at 20°C. The most virulent strain was found to have the best survival and the avirulent strain was least stable. The strain of intermediate virulence did not survive as well as the virulent strain but was more stable than the avirulent strain. Strains of L. pneumophila serogroup epidemiologically associated with legionnaires' disease had better survival in small particle aerosols than strains which were not associated with disease. Subtyping with monoclonal antibodies also showed that the type more commonly associated with disease survived longer in aerosols than the other subtypes.
Peroxide sensitivity and catalase activity in Campylobacter jejuni after injury and during recovery
Authors: Humphrey T. J.
Published: March 2008

Cells of Campylobacter jejuni damaged by freezing or mild heat showed increased sensitivity to hydrogen peroxide and also required the addition of catalase for growth on nutrient agar. These phenomena, which could have important practical consequences, were not associated, however, with changes in total catalase activity and may be due to alterations in outer membrane permeability.
Comparison of coats and surface‐dependent properties of Bacillus cereus T prepared in two sporulation environments
Authors: Foegeding P.M. , Fulp M.L.
Published: March 2008

The surface or coat‐associated properties of Bacillus cereus T spores produced from modified G medium (MGM) and fortified nutrient agar (FNA) were compared. The two populations appeared structurally similar by transmission electron microscopy. Spores prepared on FNA were more susceptible to ozone inactivation than MGM‐prepared spores. When activated by heating for 15 min at 70–85°C, FNA‐prepared spores were optimally activated at 85°C and did not become hydrophilic on heat activation while MGM spores were optimally activated at 70°C and became hydrophilic on activation. Susceptibility to removal of coat and outer membrane by chemical and enzymatic extraction treatments was measured by monitoring reduced ability to germinate in nutrients and acquired ability to germinate in the presence of lysozyme. Bacillus cereus T MGM‐prepared spores germinated in lysozyme upon<1 h exposure to sodium dodecyl sulphate‐dithiothreitol. FNA‐prepared spores were lysozyme sensitive after > 2 h treatment. Thus, B. cereus T FNA spore coats and outer membranes were more resistant to these denaturing agents. Transmission electron micrographs revealed no change in appearance of extracted spores. Sporulation environment must be considered when laboratory‐prepared spores are used to assess or predict the effect of control procedures on spores present in nature.
Minimum growth temperatures of Listeria monocytogenes and non‐haemolytic listeria
Authors: Junttila Jaana R. , Niemelä S.I. , Hirn J.
Published: March 2008

Minimum growth temperatures and those of decreased growth were determined for 100 strains of listerias. The ability of 78 strains of Listeria monocytogenes isolated from animals and 22 non‐haemolytic strains to grow at low temperatures was studied, using a flooding technique, in a plate‐type continuous temperature gradient incubator at temperatures between –1.6 and 14.5.C. The mean minimum temperature for L. monocytogenes was +1.1 0.3.C. The growth of non‐haemolytic listerias was unobservable at +1.7 0.5.C. The L. monocytogenes strains grew at about 0.6°C lower than the non‐pathogenic strains. No differences in growth temperatures were observed among L. monocytogenes strains isolated from different sources. The serovars with the OI antigen grew at lower temperatures (+1.0.3°C) than the other common serovar 4b (+1.3 0.4°C).

The results indicate that L. monocytogenes grows better than non‐haemolytic strains under cold conditions. The possible role of haemolysins as growth factors is also discussed.
In vivo transfer of pAMβ1 from Lactobacillus reuteri to Enterococcus faecalis
Authors: Morelli L. , Sarra P. G. , Bottazzi V.
Published: March 2008

Trials were conducted to determine the in vivo transferability of plasmid‐mediated antibiotic resistance between two strains of enteric Gram‐positive bacteria. Germfree mice were associated with the donor Lactobacillus reuteri DSM 20016 strain, carrying the broad host range pAMβ1 plasmid, and with the Enterococcus faecalis JH2SS recipient strain.

Analysis of faecal content of associated mice demonstrated that the in vivo transfer of this plasmid did occur and that frequencies of conjugation were affected by the presence of subtherapeutic levels of antibiotic in the diet.
The effects of temperature and pH on the ethanol tolerance of the wine yeasts, Saccharomyces cerevisiae, Candida stellata and Kloeckera apiculata
Authors: Gao Chongxiao , Fleet G. H.
Published: March 2008

The influences of temperature and pH on the survival and growth of Saccharomyces cerevisiae, Candida stellata and Kloeckera apiculata were examined in the presence of ethanol concentrations between 2.5 and 15% v/v. At 15°C, the maximum concentrations of ethanol permitting the growth of S. cerevisiae, C. stellata and K. apiculata were 15%, 11% and 9%, respectively. These maximum concentrations were decreased at 10°C and 30°C. Cells of S. cerevisiae showed no loss in viability when incubated for 12 d at 10°C or 15°C in the presence of 15% ethanol but showed some loss at 30°C. Cells of C. stellata were tolerant of 12.5% ethanol at 10°C and 15°C but not at 30°C. Cells of K. apiculata were tolerant of 10–12.5% ethanol at 15°C but not at 10°C or 30°C. Sensitivity of the yeast cells to ethanol was marginally increased on decreasing the pH from 6‐0 to 3–0.
The effect of applying lactic bacteria at ensilage on the chemical and microbiological composition of vetch, wheat and alfalfa silages
Authors: Weinberg Z. G. , Ashbell G. , Azrieli A.
Published: March 2008

The effect of applying a commercial lactic acid bacterial inoculant, at 5.6 × 104 cfu/g fresh material, to vetch, wheat, direct‐cut and wilted alfalfa silages has been studied under laboratory conditions, and on wheat also under farm conditions. Dry matter losses in the inoculated vetch and alfalfa silages were smaller than in the control silages, due to improved fermentation in the former as indicated by a faster and larger pH decrease and by a faster and larger lactic acid build‐up. Volatile fatty acid analysis also indicated more efficient fermentation patterns in the inoculated vetch and alfalfa silages with less ethanol, acetic and butyric acids compared with the respective control silages. The inoculant suppressed enterobacteria and clostridia in the inoculated direct‐cut alfalfa silage. The inoculant did not have a great effect on the wheat silages.
Plasmids in coryneform bacteria of human origin
Authors: Williams S.M. Kerry , Noble W.C.
Published: March 2008

A study of plasmids in coryneform bacteria isolated from human sources is reported. Seventy of 269 strains possessed a total of 89 plasmids. These were shown to be of varying sizes and in some cases of varying structures by endonuclease restriction digest. In six of 20 strains antibiotic resistance was cured with loss of the plasmid. The diversity of plasmids is emphasized.
Mechanism of resistance of Bacillus subtilis spores to chlorhexidine
Authors: Shaker L.A. , Furr J.R. , Russell A.D.
Published: March 2008

Chlorhexidine diacetate (CHA) was rather more sporicidal at 20C to ureadithreitol‐sodium lauryl sulphate (UDS)‐treated spores of Bacillus subtilis NCTC 8236 than to urea‐dithiothreitol (UDT)‐treated or normal (untreated) spores. UDS spores adsorbed more CHA from solution than did the other two forms. No differences in hydrophobicity, as determined by hydrophobic interaction chromatography (HIC) or bacterial adherence to hydrocarbon (BATH), could be detected between the three spore types. Germinating spores took up much less CHA than did outgrowing spores. Germinating cells were considerably more hydrophobic, as measured by the BATH technique, than outgrowing cells or normal spores. Chlorhexidine diacetate increased the apparent hydrophobicity of the two latter forms, but this effect could be partially reversed by subsequent exposure to a non‐ionic surfactant.
Starvation and nutrient resuscitation of Klebsiella pneumoniae isolated from oil well waters
Authors: Lappin‐Scott H.M. , Cusack F. , MacLeod A. , Costerton J.W.
Published: March 2008

Klebsiella pneumoniae isolated from oil well waters reduced in size in response to nutrient starvation. The cells remained viable during starvation and later were able to grow rapidly when stimulated by nutrients. The heterotrophic potential, culture absorbance and extracellular polysaccharide production decreased during cell starvation whereas an initial increase in colony‐forming units was observed on agar plates. Transmission electron microscopy (TEM) after 24 d revealed that the cells had changed to small rods or cocci between 0.5 by 0.25 μm and 0.87 by 0.55 μm. When transferred to half‐strength brain heart infusion medium, TEM showed cell division and rod‐shaped cells after 45 min and full resuscitation within 4 h. Cell response was much slower in sodium citrate medium and resuscitation took 8 h.
Detection of wine‐spoiling yeasts by electronic methods
Authors: Henschke P. A. , Thomas D. Susan
Published: March 2008

Electronic techniques for the estimation of micro‐organisms have been used widely in the food industry because they entail minimal sample preparation, provide continuous automatic monitoring, produce relatively rapid results and incur low running costs. Electrical measurements have been evaluated for use in the alcoholic beverage industry to differentiate between wine‐spoiling and non‐wine‐spoiling yeast contaminants. Suitable media, supplemented with ethanol to inhibit the growth of non‐wine‐spoilage yeasts, are described for use with the Bactometers models 32 and M123. A procedure for detecting spoilage yeasts in opaque alcohol‐based drinks is also described.
A note on the effect of storage on the chemical resistance of spores of Bacillus subtilis SA22 and Bacillus subtilis globigii B17
Authors: Leaper S. , Bloor K.
Published: March 2008

Spores of Bacillus subtilis SA22, harvested from nutrient agar after 9 d at 30°C and stored in distilled water at 4°C, were unaltered in their resistance to 17.7% hydrogen peroxide or 0.04% peracetic acid after storage for up to 134 weeks. Three spore crops of B. subtilis globigii were unaffected by storage for up to 134 weeks with respect to 17.7% hydrogen peroxide resistance but were significantly more resistant to 0.04% peracetic acid following storage.
Plant growth‐altering effects of Azospirillum brasilense and Bacillus C–11–25 on two wheat cultivars
Authors: Kucey R.M.N.
Published: March 2008

The effect of Azospirillum brasilense Cd, Bacillus C–11–25, indole acetic acid, gibberellic acid and cytokinin on plant growth characteristics of two wheat (Triticum aestivum L. emend Thell) cultivars was studied under laboratory and greenhouse conditions. Responses of wheat plants to bacterial inoculation were similar to those caused by the addition of gibberellic acid in growth pouches. Chester and Fielder wheat varieties differed in responses to the bacteria and hormone additions. When added to growth pouches, bacterial culture filtrates and dead bacterial cells caused plant growth responses similar to those caused by the addition of live cells. Bacteria and hormone additions resulted in increased permeability of Fielder wheat to 15Nlabelled nitrate, and decreased nitrate permeability of Chester wheat. Bacterial inoculation of soil in pots caused 15N isotope dilution in Fielder but not in Chester wheat. Hormone addition to pots caused isotope dilution in Chester wheat. It appeared that genetic differences between cultivars affected plant growth responses. The accuracy of estimates of N2 fixation by associative bacteria based on 15N isotope dilution calculations may be reduced if control plants differ in plant response to these bacteria.
Microbial spoilage of pre‐cooked potato‐topped pies
Authors: Thomas C.J. , Masters F.
Published: March 2008

The ecological succession of bacteria which developed in pre‐cooked potato‐topped pies stored at two different temperatures was examined. Bacillus, Streptococcus and Staphylococcus‐Micrococcus spp. were the predominant organisms isolated from freshly prepared pies and those stored at 4°C and 37°C. None of these groups of bacteria caused significant biodeterioration of pies held at 4°C, but all groups grew well in pies stored at 37°C and achieved counts of ca 108/g of sample. Bacillus spp. were the first group to grow, followed by Streptococcus and Staphylococcus‐ Micrococcus spp. Growth which occurred at 37°C did so at the expense of glucose, lactate accumulated and the pH of pie components decreased. Amylase activity detected in all pie components during storage was associated with the growth of Bacillus spp. and probably supplemented glucose already present in pies, by hydrolytic cleavage of potato, flour or binder starches. Spoilage caused by growth and activity of the bacteria isolated was not associated with visual signs of bio‐deterioration, nor production of ‘off’ odour usually associated with spoilage of meats. These results suggest that pre‐cooked potato‐topped pies held at inappropriate temperatures represent a potential public health risk.
Growth and formation of toxin by Clostridium botulinum in peeled, inoculated, vacuum‐packed potatoes after a double pasteurization and storage at 25°C
Authors: Lund Barbara M. , Graham Ann F. , George Susan M.
Published: March 2008

A process that claims to use a double pasteurization to produce vacuum‐packed potatoes for storage at ambient temperature has been evaluated. After the first pasteurization, potatoes are vacuum‐packed and stored at 25°C–35°C for up to 24 h, which is intended to allow germination of bacterial spores, and are then pasteurized again. When potatoes were inoculated with spores of Clostridium botulinum and subjected to this double‐pasteurization process a high proportion of spores remained viable and resulted in growth and formation of toxin within 5–9 d at 25°C. To provide an appropriate reduction in the risk of survival and growth of Cl. botulinum, peeled, vacuum‐packed potatoes for storage at ambient temperature should be given a heat treatment equivalent to an F03 process. If they are not given such a heat treatment they should be stored at a temperature below 4°C.
A numerical taxonomic study of non‐motile non‐fermentative Gram‐negative bacteria from foods
Authors: Shaw B.G. , Latty Josephine B.
Published: March 2008

A numerical taxonomic study using 155 unit characters was performed on 63 strains of Gram‐negative non‐motile non‐fermentative bacteria isolated from proteinaceous foods. Similar bacteria from other sources and several Pseudomonas strains from meat were included for reference purposes. Three clusters were observed at 76% S which contained all the food strains. Cluster 1 was composed entirely of Acinetobacter strains including 17 isolated from foods that were provisionally identified with Acinetobacter johnsonii. Cluster 2 contained 22 strains identified as Psychrobacter immobilis, of which 20 were from food. Cluster 3 contained all the Pseudomonas reference strains and 26 non‐motile strains isolated from meat. These were shown to be non‐motile variants of Pseudomonas fragi. A simple identification scheme, based on five tests, is presented for the distinction of the three types of bacteria.