bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudomonas tolaasii in cultivated mushroom (Agaricus bisporus) crops: effects of sodium hypochlorite on the bacterium and on blotch disease severity
Authors: WONG W.C. , PREECE T.F.
Published: March 2008

Sodium hypochlorite killed Pseudomonas tolaasii in water in 30 s at pH 6.0 when 5 mg/1 free available chlorine (FAC) was used. On glass beads 62.5 mg/1 FAC was necessary to kill the pathogen in 30 s. Peat and limestone mixture (‘casing’) prevented some cells of the pathogen being killed by chlorine. Casing treated with 50 and 100 mg/1 FAC still contained some Ps. tolaasii cells which were later able to multiply. Although some viable cells of the pathogen survived the use of 150 mg/1 FAC these were apparently unable to multiply. Mushroom tissue is more ‘disinfectant‐wasting’ than casing, the pathogen on it surviving 250 mg/1 FAC for 10 min. In controlled environmental experiments, use of 150 mg/1 FAC at mushroom ‘pinning’ (2.5 mm diameter primordia) gave as much control of blotch disease as was obtainable if chlorination began after casing. Delay in starting chlorination until the mushrooms were 10 to 15 mm in diameter resulted in blotch disease incidence and severity as severe as in unchlorinated controls. Disease incidence was not reduced when 50, 100 and 150 mg/1 FAC was used, but disease severity was significantly reduced when 150 mg/1 was used. Adjusting the pH of the water did not affect these results. On commercial farms, routine watering with 150 mg/1 FAC starting at pinning, checked frequently by the sodium arsenite titrimetric method, for 3 years, reduced the percentage of mushrooms discarded because of very severe Ps. tolaasii blotch from 5.2% to 0.6% on one farm and from 7.4% to 0.5% on another, but did not eliminate the disease completely.
Pseudomonas tolaasii in mushroom (Agaricus bisporus) crops: activity of formulations of 2‐bromo‐2‐nitropropane‐1,3‐diol (bronopol) against the bacterium and the use of this compound to control blotch disease
Authors: WONG W.C. , PREECE T.F.
Published: March 2008

The bactericidal activity of 2‐bromo‐2‐nitropropane‐1,3‐diol (bronopol) against Pseudomonas tolaasii, the causative organism of mushroom bacterial blotch, is enhanced by the addition of Tween 80, EDTA and phenylethanol. Results of tests with this pseudomonad confirm that bronopol is more active in alkaline solutions and enhancement of the bactericidal activity of this compound can be obtained by adding calcium carbonate, or mushroom casing (limestone and peat). Quantitative observations show that sterility can be achieved with bronopol at 100 µg/ml in 24 h following artificial inoculation of casing with Ps. tolaasii in glass flasks. On miniature mushroom beds in controlled environments a single application of bronopol, in tap water during routine watering, controls bacterial blotch disease. Bronopol is a slow‐acting bactericide, destroying Ps. tolaasii in mushroom casing and effecting control of bacterial blotch disease.
Towards microbiological quality assurance in radiation sterilization processing: a limiting case model
Authors: DOOLAN P.T. , DWYER J. , DWYER V.M. , FITCH F.R. , HALLS N.A. , TALLENTIRE A.
Published: March 2008

A Limiting Case Model has been developed which describes the dependence on radiation dose of the proportion of items, in a population of items subjected to irradiation, which are contaminated by one or more organisms. This model is independent of the initial distribution of numbers of micro‐organisms on items and represents a conservative approach to estimation of the proportions of non‐sterile items in an irradiated population of items.
Nitrogen metabolism by the microbial flora of the rabbit caecum
Authors: FORSYTHE S.J. , PARKER D.S.
Published: March 2008

The dense microbial flora of the rabbit caecum consisted chiefly of bacteria (1011/g) with small numbers of yeast cells (106/g). Using strictly anaerobic techniques, 23% of the direct microscopic cell count was cultivated and 55% of the cultivatable bacteria utilized ammonia as the sole source of nitrogen. Ureolytic bacteria were isolated from the caecal lumen and mucosa and were identified as Bacteroides vulgatus, Clostridium clostridiiforme, Bacillus spp. and Staphylococcus spp. Ammonia assimilation by the bacterial flora of the caecum was by incorporation into α‐oxoglutarate catalysed by NADPH‐linked glutamate dehydrogenase.
Potency factors in the delta‐endotoxin of Bacillus thuringiensis var. aizawi and the significance of plasmids in their control
Authors: JARRETT P.
Published: March 2008

Mutants defective in delta‐endotoxin crystal production from four closely related isolates of Bacillus thuringiensis var. aizawi with aizawi serotype crystals were as vigorous as the parents in terms of growth, extracellular protease production, sporulation and heat resistance of spores. Spores produced by mutants germinated faster than wild type spores possibly due to deficiency of protein, in the form of delta‐endotoxin in the spore coat. Acrystalliferous (cry—) mutants were not active in Galleria mellonella or Pieris brassicae larvae. Mutants with small crystals (sm cry) lost activity or gained extra activity against either one or the other host, revealing the presence of different toxicity factors. Solubilized crystals of parent isolates were composed of two major polypeptides with Mr values of 130 000 and 138 000. Sm cry mutants lost either polypeptide irrespective of which insect potency had been lost. Some cry — and some sm cry mutants had the same plasmid pattern as the parent; others lost one plasmid sometimes gaining another of different size. No consistent correlation was found between plasmid loss in mutants and any loss or increase of potency indicated by bioassays. It is concluded that the delta‐endotoxins of the isolates under investigation are composed of at least two toxins. The results suggest that genes coding for the production of toxic factors or for their expression may be carried on both the plasmids and the chromosome.
Analysis of cellular fatty acids by gas chromatography as a tool in the identification of medically important coryneform bacteria
Authors: ATHALYE M. , NOBLE W.C. , MINNIKIN D.E.
Published: March 2008

The fatty acid methyl esters of nineteen unidentified pathogenic coryneform bacteria were analysed by gas‐liquid chromatography and the resulting profiles were compared with those of type or reference strains of possibly related species, namely Caseobacter polymorphus, Corynebacterium bovis, C. diphtheriae, C. xerosis and Rhodococcus equi. All of the strains had distinct fatty acid profiles but most of them conformed to a general pattern, with high levels of octadecanoic acids and only trace amounts of 10‐methyl octadecanoic acid (tuberculostearic acid). These profiles were very similar to those from C. diphtheriae and C. xerosis but could be differentiated from C. bovis, Cas. polymorphus, R. equi and two unidentified pathogenic strains which had significantly higher levels of tuberculostearic acid.
Trimethoprim resistance plasmids in Escherichia coli isolated from cases of diarrhoea in cattle, pigs and sheep
Authors: WISE P.J. , TOWNER K.J. , WEBSTER C.A. , SLACK R.C.B. , JONES T.O.
Published: March 2008

A total of 1572 isolates of Escherichia coli obtained from the faeces of young farm animals with diarrhoea over the period 1980–1983 were screened for resistance to trimethoprim (Tp). Resistance to Tp was detected in263/954 (28%) of bovine isolates,59/441 (13%) of porcine isolates and15/177 (9%) of ovine isolates. Seventy‐five resistant isolates from separate outbreaks of infection on farms within a 25 mile radius of Nottingham were examined in detail. Sixty‐eight (91%) of the 75 isolates were resistant to > 1024 mg Tp/1 and 34 (50%) of these ‘highly resistant’ isolates (45% of total resistant isolates) transferred their Tp resistance to E. coli K12. A further 13 (17%) isolates were demonstrated to carry non‐self‐transferable plasmids which were capable of being mobilized to E. coli K12 by the broad host range plasmid RP4. Thirty‐one self‐transferable Tp R plasmids were divided between the following incompatibility groups: IncB (14 plasmids), IncF***H (4 plasmids), IncH2 (1 plasmid), IncIaP (10 plasmids), IncIdT (1 plasmid) and IncP (1 plasmid). In terms of antibiotic resistance patterns and incompatibility properties, many of these plasmids closely resembled those isolated from human patients in the same area, suggesting that there may be a common pool of Tp R plasmids.
A note on crossing experiments with Aspergillus niger for the production of calcium gluconate
Authors: Kundu P.M. , Das A.
Published: March 2008

Kundu, P.N. & Das, A. 1985. A note on crossing experiments with Aspergillus niger for the production of calcium gluconate. Journal of Applied Bacteriology59, 1–5.

A strong calcium gluconate‐producing strain of Aspergillus niger (MN181) was obtained by way of mutagenic treatment. Its growth was very slow with moderate sporulation. The strain was treated with N‐methyl‐N‐nitro‐N‐nitrosoguanidne (MNNG) and some auxotrophic mutants were obtained. All were less productive than the parent strain in producing calcium gluconate. The reduced yield was corrected in the heterokaryons and diploids derived by crossing sister strains. One diploid strain (D4), heterozygous for auxotrophy and conidial colour markers was grown in the presence of 4% alcohol and 31 segregants were isolated which included both haploid and diploid strains. Their yields were studied and some recombinants were obtained which, in spite of the same yield of MN181, showed improvement in giving fast growth and abundant sporulation.
Recovery of heat‐stressed yeasts in media containing plant oleoresins
Authors: Conner D.E. , Beuchat L.R.
Published: March 2008

Conner, D.E. & Beuchat, L.R. 1985. Recovery of heat‐stressed yeasts in media containing plant oleoresins. Journal of Applied Bacteriology59, 49–55.

Oleoresins from seven plants (allspice, cinnamon, clove, garlic, onion, oregano, and thyme) were tested for their effects on eight genera of sublethally heated food‐spoilage and industrially important yeasts (Candida lipolytica, Debaryomyces han‐senii, Hansenula anomala, Kloeckera apiculata, Lodderomyces elongisporus, Rhodotorula rubra, Saccharomyces cerevisiae, and Torulopsis glabrata). All heat‐stressed yeasts had increased sensitivity to oleoresins in recovery media. Heated cells were most sensitive to cinnamon oleoresin, a lethal effect being observed to concentrations as low as 5 μg/ml. Results indicate that all eight yeasts underwent metabolic and/or structural injury as a result of exposure to elevated temperature. Whilst changes in sensitivity to oleoresins were not the same for all yeasts, it is concluded that the oleoresins may have a pronounced synergistic or additive effect on thermal inactivation of yeasts in foods. Furthermore, carryover of oleoresins in low dilutions of food to enumeration media could adversely influence the recovery of heat‐stressed cells, thus resulting in apparent low populations.
A note on an in vitro test system to compare the bactericidal properties of wound dressings
Authors: Holland K.T. , Davis W.
Published: March 2008

Holland, K.T. & Davis, W. 1985. A note on an in vitro test system to compare the bactericidal properties of wound dressing. Journal of Applied Bacteriology59, 61–63.

An in vitro method of comparing the antimicrobial properties of dressings used on human skin is described and has been tested with two samples of tulle gras. The method has advantages over agar diffusion methods by providing flexibility of test conditions and kinetic data for analysis.
Application of current methods for isolation and identification of staphylococci in raw bovine milk
Authors: Harvey J. , Gilmour A.
Published: March 2008

Harvey, J. & Gilmour, A. 1985. Application of current methods for isolation and identification of staphylococci in raw bovine milk. Journal of Applied Bacteriology59, 207–221.

Samples of raw milk were examined for counts of somatic cells, total viable bacteria, staphylococci (Schleifer & Kramer' medium) and Staphylococcus aureus (Baird‐Parker medium, Baird‐Parker medium with pig plasma and Baird‐Parker medium with additional antibiotics). For the isolation of staphylococci from raw milk, Schleifer & Kramer' medium was found to be very selective and in general performed satisfactorily. From the results obtained with the three remaining media the continued use of Baird‐Parker medium for isolation of Staph. aureus from raw milk is recommended with the proviso that colonies selected for identification should include those that clear and do not clear the egg yolk and are not limited to colonies with diameters > 1 mm. Staphylococci isolated from raw milk were identified by key tests using a multipoint inoculation procedure. A selected number were also examined by the API STAPH system in conjunction with the API LAB computer programme for identification of staphylococci. Of the staphylococci examined, 90–0% were identified using the multipoint procedure. For strains identified as Staph. aureus, Staph. hyicus subsp. hyicus, Staph. epidermidis, Staph. simulans, Staph. xylosus or members of the Staph. hominis/Staph. warneri/Staph haemolyticus group, the API system provided confirmatory evidence. With strains identified by the multipoint procedure as Staph. hyicus subsp. chromogenes, Staph. sciuri subsp. sciuri and Staph. sciuri subsp. lentus the API system did not always provide concurring results. Several strains which could not be identified by the multipoint procedure could be identified by the API system. Staph. aureus, Staph. hyicus subsp. hyicus and Staph. hyicus subsp. chromogenes strains isolated from milk were examined for production of enterotoxin A‐E. Only 3–9% of Staph. aureus strains examined produced detectable enterotoxin (type C). None of the Staph. hyicus subsp. hyicus or Staph. hyicus subsp. chromogenes strains produced any of the known enterotoxins.
Malachite green pre‐enrichment medium for improved salmonella isolation from heavily contaminated samples
Authors: Schothorst M. van , Renaud A. M.
Published: March 2008

Van Schothorst, M. & Renaud, A. M. 1985. Malachite green pre‐enrichment for improved salmonella isolation from heavily contaminated samples. Journal of Applied Bacteriology59, 223–230.

Large numbers of competitive bacteria may hinder the isolation of salmonellas from food and environmental samples when a pre‐enrichment method is used. The addition of 0.1 g/1 of malachite green (MG) to buffered peptone water (BPW) inhibited the multiplication of Gram‐positive bacteria. Brilliant green had a similar effect but only when the normal recommended concentration of 0.02 g/1 was raised to 0.05 g/1. Pure strains of salmonellas were inhibited by MG in BPW, but addition of non fat dried milk (NFDM) (5 g/1 or more) counteracted this effect. MG did not affect the recovery of salmonellas injured by heat, freezing, low water activity or acidity in BPW with NFDM. It was concluded that addition of MG to BPW may improve the possibility of isolating salmonellas from heavily contaminated materials by limiting the competitive growth of Gram‐positive bacteria and the subsequent lowering of the pH of the broth.
The establishment of reproducible, complex communities of oral bacteria in the chemostat using defined inocula
Authors: McKee Ailsa S. , McDermid Ann S. , Ellwood D.C. , Marsh P.D.
Published: March 2008

McKee, A.S., McDermid, A.S., Ellwood, D.C. & Marsh, P.D. The establishment of reproducible, complex communities of oral bacteria in the chemostat using defined inocula. Journal of Applied Bacteriology59, 263–275.

Nine commonly isolated oral bacterial populations were inoculated into a glucose‐limited and a glucose‐excess (ammo acid‐limited) chemostat maintained at a constant pH 7.0 and a mean community generation time of 13.9 h. The bacterial populations were Streptococcus mutans ATCC 2–27351, Strep, sanguis NCTC 7865, Strep, mitior EF 186, Actinomyces viscosus WVU 627, Lactobacillus casei AC 413, Neisseria sp. A1078, Veillonella alkalescens ATCC 17745, Bacteroides intermedius T 588 and Fusobacterium nucleatum NCTC 10593. All nine populations became established in the glucose‐limited chemostat although Strep, sanguis and Neisseria sp. were present only after a second and third inoculation, respectively. In contrast, even following repeated inoculations, Strep, mutans, B. intermedius and Neisseria sp. could not be maintained under glucose‐excess conditions. A more extensive pattern of fermentation products and amino acid catabolism occurred under glucose‐limited growth; this simultaneous utilization of mixed substrates also contributed to the higher yields (Y molar glucose) and greater species diversity of these communities. Microscopic and biochemical evidence suggested that cell‐to‐cell interactions and food chains were occurring among community members. To compare the repro‐ductibility of this system, communities were established on three occasions under glucose‐limitation and twice under glucose‐excess conditions. The bacterial composition of the steady‐state communities and their metabolic behaviour were similar when grown under identical conditions but varied in a consistent manner according to the nutrient responsible for limiting growth. Although a direct simulation of the oral cavity was not attempted, the results show that the chemostat could be used as an environmentally‐related model to grow complex but reproducible communities of oral bacteria for long periods from a defined inoculum.
A bacteriological investigation of the effectiveness of cleaning and disinfection procedures for toilet hygiene
Authors: Scott Elizabeth , Bloomfield Sally F.
Published: March 2008

Scott, E. & Bloomfield, S.F. 1985. A bacteriological investigation of the effectiveness of cleaning and disinfection procedures for toilet hygiene, Journal of Applied Bacteriology59, 291–297.

The bacterial contamination of hospital and institutional toilets and toilet areas which were cleaned daily was investigated. The effect of daily disinfection with hypochlorite or a quaternary ammonium product, or with a continuous‐release hypochlorite disinfectant system, based on the chlorine‐releasing agent trichloro‐isocyanuric acid, was determined. The continuous release system produced substantial and sustained reduction in contamination of the toilet itself (water, toilet bowl and rim) and some reduction in contamination of sites surrounding the toilet (seat, floor, and air). By contrast, although daily disinfection produced some reduction in contamination compared with daily cleaning, the reductions were less than that associated with the continuous release system and indicated the inadequacy of daily disinfection and/or cleaning for toilets where effective procedures are required.
Fatty acid composition and mycolic acid pattern of some chromogenic mycobacteria
Authors: Valero‐Guillén P.L. , Pacheco F. , MartÍn‐Luengo F.
Published: March 2008

Twenty‐nine strains of chromogenic mycobacteria belonging to the species Myco‐bacterium aurum (5 strains), M. duvalii (2), M. flavescens (1), M. gordonae (6), M. kansasii (3), M. obuense (1), M. parafortuitum (3), M. phlei (2), M. rhodesiae (1), M. vaccae (2) and Mycobacterium spp. (3) were studied for fatty acid composition and mycolic acid patterns by gas‐liquid chromatography and thin‐layer chromatog‐raphy respectively. Fatty acids found ranged from those with 12–24 carbon atoms and were saturated and monounsaturated straight chain fatty acids, along with 10‐methyl branched of 16, 17 and 18 (tuberculostearic acid) carbon atoms. Moreover, 2‐methyl tetradecanoic acid was found in M. gordonae, M. kansasii and Mycobacterium spp. (2 strains), and 2,4‐dimethyl tetradecanoic acid in M. kansasii and Mycobacterium spp. (2 strains). Nonadecenoic acid was found only in M. flavescens and tuberculostearic acid was not detected in M. gordonae. Three patterns of mycolic acids were obtained: the first, found in M. aurum, M. flavescens, M. phlei, M. rhodesiae and Mycobacterium spp. (1 strain), was characterized by the presence of several spots assigned to α‐mycolates, keto‐mycolates and wax‐ester mycolates (ω‐carboxy‐rnycolates and 2‐eicosanol and related alcohols); the second, found in M. duvalii, M. obuense, M. parafortuitum and M. vaccae was similar to the first, but it contained an additional spot of α‐mycolates; the third pattern, found in M. gordonae, M. kansasii and Mycohacterium spp. (2 strains) contained three spots considered to be α‐mycoiates, methoxy‐mycolates and keto‐mycolates. The results obtained confirm previously reported data on the fatty and mycolic acid composition of the species studied.
Towards microbiological quality assurance in radiation sterilization processing: the limiting case model applied to a microbial population having a distribution of radiation responses
Authors: Dwyer J. , Fitch F.R. , Doolan P.T. , Dwyer V.M. , Halls N.A. , Tallentire A.
Published: March 2008

A limiting case model, developed earlier to provide a conservative estimate of the proportion of non‐sterile items (P) in an irradiated population of items contaminated with micro‐organisms of a single type, has been extended to include items having organisms of different types. Estimates of P are compared with exact values derived on purely theoretical grounds and with values obtained by computer simulation of microbiological inactivation on items.
A numerical taxonomic study of Flavobacterium‐Cytophaga strains from dairy sources
Authors: Jooste P.J. , Britz T.J. , Haast J. De
Published: March 2008

Phenotypic data on 203 Gram‐negative non‐fermentative bacteria of the Flavobacterium‐Cytophaga group isolated from milk and butter were analyzed by numerical taxonomic techniques. Twenty reference strains including species of Flavobacterium, Cytophaga and strains of Pseudomonas paucimobilis were included in the study. Using the matching coefficient of Sokal & Michener with antibiotic susceptibility data included, 139 isolates were recovered in nine clusters. Six of these clusters were linked at or above the 85% S level while three were linked at or above the 79% S level. The largest cluster, representing 46.3% of the isolates, could be equated with Flavobacterium sp. Group IIb. Other clusters could be equated with Flavobacterium sp. L 16/1 (22.7% of isolates), F. balustinum (10.8% of isolates), F. breve (4.4%), F. multivorum (3.5%) and Cytophaga johnsonae (1.5%). The cluster resembling Flavobacterium sp. L 16/1 and a smaller unclassified cluster, were exceptional in being susceptible to the antibiotics cephalothin and penicillin G.
A note on the use of metal species in microbiological tests involving growth media
Authors: Bird N.P. , Chambers J.G. , Leech R.W. , Cummins D.
Published: March 2008

The feasibility of using traditional growth media for biological testing of metal species, for example as potential microbiocides, was investigated. Significant interactions between both of the representative metal species studied, Cu2+ and FeEDTA, and the test media were found. It is recommended that the use of growth media for tests on metal species should be avoided.
Soft rot Erwinia bacteria in the rhizosphere of weeds and crop plants in Colorado, United States and Scotland
Authors: McCarter‐Zorner Nancy J. , Harrison M.D. , Franc G.D. , Quinn C.E. , Sells I. Ann , Graham D.C.
Published: March 2008

The soft rot coliform bacteria Erwinia carotovora subsp. carotovora and E. carotovora subsp. atroseptica were isolated by an enrichment method from the rhizosphere of many weed species and crop plants, collected in commercial potato fields either currently in potatoes or in a different crop as part of the rotation. Erwinia carotovora was isolated from 24 plant species in Colorado and 47 species in Scotland. Weeds contaminated with E. carotovora were found in fields growing other crops in which potatoes had not been grown for 1–2 and sometimes much longer. Weeds collected from virgin land in Colorado were not contaminated with E. carotovora but in Scotland virgin soils containing weed roots yielded E. carotovora subsp. carotovora. In general, the numbers of contaminated weeds rose from nil or low levels in spring and early summer to considerably higher levels during mid‐season, and fell to progressively lower levels later. Erwinia carotovora subsp. carotovora was the predominant organism recovered from the rhizosphere, but E. carotovora subsp. atroseptica was less common, especially in Scotland, and its incidence varied in different seasons depending on factors such as temperature and moisture conditions. The bacteria could apparently persist in the root zone for an extended period of time and may be a source of inoculum to contaminate soft rot erwinia‐free seed potato stocks; the origin of the bacteria was uncertain.
A note on Pseudomonas syringae pv. berberidis infections of Berberis: comparative infection studies in attached and detached leaves
Authors: Roberts S.J.
Published: March 2008

Results of infectivity titrations were compared for attached and detached leaves of Berberis gagnepainii (evergreen) and B. vulgaris (deciduous) inoculated with Pseudomonas syringae pv. berberidis. In B. vulgaris results for attached and detached leaves were not comparable because of difficulties in maintaining detached leaves in a viable state. In B. gagnepainii infection of detached leaves occurred following inoculation with as few as 1.1 cfu. The slopes (b) of probit response/log dose curves were < 2 suggesting that cells of Ps. syringae pv. berberidis act individually and independently of each other following inoculation, which is further supported by values obtained for response time (RT50) and their distributions. No significant differences (P = 0.05) were found between attached and detached leaves of B. gagnepainii, for values of RT50, ED50 or b, suggesting that detached leaves of B. gagnepainii might be useful for the study of this leaf spot disease.
A note on the enumeration of manganese‐oxidizing bacteria in estuarine water and sediment samples
Authors: Vojak P.W.L. , Edwards C. , Jones M.V.
Published: March 2008

Vojak, P.W.L., Edwards, C. & Jones, M.V. 1985. A note on the enumeration of manganese‐oxidizing bacteria in estuarine water and sediment samples. Journal at Applied Bacteriology 59, 375–379.

Media for the enumeration of manganese‐oxidizing bacteria in estuarine water and sediment samples were compared. A peptone/yeast extract medium containing manganese sulphate and 30% (v/v) sea salts solution gave the highest percentage of manganese‐oxidizers and high total viable counts. A survey of estuarine (River Tamar) and marine (English Channel) sites indicated that manganese‐oxidizing bacteria comprise a significant but variable proportion (11–85%) of the total bacterial count.
A note on the attachment rate of suspended bacteria to submerged aquatic plants in a calcareous stream
Authors: Rimes Carrie A. , Goulder R.
Published: March 2008

The density of epiphytic bacteria on leaflets of laboratory‐grown Apium nodiflorum, immersed in calcareous stream water, increased linearly with time over 10 h, both in the laboratory and in the field. This increase was probably due to attachment of suspended bacteria. The rate of attachment to leaflets of plants, immersed in a stream at different concentrations of suspended bacteria, was linearly related to the concentration of suspended bacteria. The attachment rate, relative to concentration, was 1.7 × 104 bacteria/cm2/h for each 105 bacteria/ml in the surrounding water.
Effect of free‐radical and oxygen scavengers on photochemically generated oxygen toxicity and on the aerotolerance of Campylobacter jejuni
Authors: Juven B. J. , Rosenthal I.
Published: March 2008

Exposure of a nutrient agar medium to the combined action of fluorescent light and air produced toxic factors in the medium which affected the growth of Campylobacter jejuni. Sodium dithionite (5–10 mM), a powerful reducing agent, and catalase were effective in counteracting the injurious action of light and air. Among the quenchers of singlet oxygen tested, only histidine had a beneficial effect on the recovery of C. jejuni in the photo‐oxidized medium, while the addition of superoxide dismutase, a hydroxyl radical scavenger such as cysteamine, or the free radical antioxidants tocopherol and butylated hydroxy toluene, did not increase the recovery rate of photochemically injured cells. Histidine (40 mM) and dithionite (5–10 mM) also assisted recovery of C. jejuni inoculated on nutrient agar stored in air in the dark. Cysteamine and dithionite were toxic to Campylobacter when added at concentrations of ≥10 mM and ≥ 20 mM, respectively. A high inoculum of C. jejuni could not be recovered in unsupplemented nutrient agar incubated in air but was recovered in atmospheres containing 17 or 21% oxygen plus 10% carbon dioxide. The addition of dithionite, catalase or histidine resulted in some colony formation on nutrient agar incubated in air. Among the scavengers tested, only dithionite was consistently able to maintain the viability of C. jejuni on nutrient agar stored in air for longer than 4 weeks. In view of the ability of catalase, dithionite and histidine to enhance the aerotolerance of C. jejuni, it is concluded that various oxygen species might be involved in the toxicity of high levels of oxygen.
An inventory of peptide hydrolases and arylamidases inFlavobacterium IIb
Authors: Milliere J.B. , Veillet‐Poncet L.
Published: March 2008

The determination of the number and the specificity of peptide hydrolases and arylamidases present in a cell‐free sonicate fromFlavobacterium IIb, a species phenotypically similar toFlavobacterium balustinum, involved polyacrylamide gel electrophoresis and coloration of end products or staining procedures using diazotation reactions. Only substrates with L‐configuration amino acids and dipeptides with an unsubstituted RN‐group were cleaved. One protein band, that was able to hydrolyse skimmed milk agar, was observed but carboxypeptidase and endopep‐tidase (chymotrypsin and trypsin activities) were absent. Zymograms exhibited ary‐lamidase, dipeptidase and tripeptidase activities. Results underline the distinction between the L‐leucine aminopeptidase and the L‐leucylarylamidase.
Multiple modes of inhibition of spore germination and outgrowth by reduced pH and sorbate
Authors: Blocher J.C. , Busta F.F.
Published: March 2008

Germination and outgrowth of three strains of Clostridium botulinum in PYEG medium were measured by phase contrast microscopy. Reduction in pH from 7 to 5·5 completely inhibited germination of strain 12885A, reduced the extent of germination of strain 62A and had no effect on the extent of germination of strain 53B. At pH 5·5, 225 mg/1 of undissociated sorbic acid had no effect on the germination of strain 53B, while at pH 6·5, 225 mg/1 of undissociated sorbic acid completely inhibited germination of strains 62A and 12885A. Outgrowth of germinated spores of strains 62A and 53B was not inhibited at pH 5·5, but the addition of sorbate (225 mg/1 undissociated sorbic acid) completely inhibited outgrowth. Sorbate inhibited germination of Cl. botulinum and Bacillus cereus spores triggered to germinate by amino acids. Inhibition occurred after germinant binding, as measured by commitment to germinate.
Wild birds and silage as reservoirs of Listeria in the agricultural environment
Authors: Fenlon D.R.
Published: March 2008

A method for the isolation of listeria which enabled a more rapid detection of the organism was used to examine samples of silage and bird faeces. Faecal samples indicated that seagulls feeding at sewage works had a higher rate of carriage than those elsewhere. Faecal samples from rooks generally suggested a low incidence of listeria except on one occasion when eight of twenty samples contained Listeria monocytogenes: this coincided with the nesting season and the peak period for listeriosis in sheep. The incidence of L. monocytogenes in clamp silages ranged from 2.5–5.9%, but in samples of big bale silages the incidence was 22.2% and, when mouldy samples were selected, 44%.
The influence of the host on expression of intestinal microbial enzyme activities involved in metabolism of foreign compounds
Authors: Cole C.B. , Fuller R. , Mallet A. K. , Rowland I. R.
Published: March 2008

The activities of four enzymes (β‐glucosidase, β‐glucuronidase, nitrate reductase and nitroreductase) in selected intestinal bacteria (Escherichia coli, Clostridium sp., Streptococcus sp., Bacteroides sp. and Lactobacillus salivarius) were measured after growth in vitro and in vivo. The five strains differed in their activites with Clostridium sp. being the most active for β‐gjucosidase, β‐glucuronidase and nitroreductase, and E. coli the most active producer of nitrate reductase. Enzyme activity in vivo tended to be higher than in vitro but there were instances where the comparative activities were reversed.
Thermal resistance variations due to post‐harvest treatments in Bacillus subtilis spores
Authors: Gorman S.P. , Scott E.M. , Hutchinson E.P.
Published: March 2008

Spores of Bacillus subtilis NCTC 10073 were produced using three different methods on solid and liquid defined media. Thermal resistance at 90d̀C was examined in relation to the effects of cleaning procedures such as number of washings, speed and temperature of centrifugation on the spores. Ion‐exchange spore forms (hydrogen and calcium) and coat‐defective forms (urea‐mercaptoethanol and urea‐dithiothreitol‐sodium dodecyl sulphate) were prepared from spores produced by the different spore production methods and compared for thermal resistance. The resistance patterns observed are discussed in terms of the spore properties of germinability. colony formation, dipicolinic acid and calcium contents.
Inactivation of Bacillus spores by gaseous ozone
Authors: Ishizaki Kozo , Shinriki Nariko , Matsuyama Hidetoshi
Published: March 2008

The sporicidal activity of ozone in the gas phase was investigated. Spores of six strains of Bacillus species deposited on filter paper or glass fibre filter were conditioned at different relative humidities (r.h.), and then exposed to ozone ranging in concentration from 0.5 to 3.0 mg/1 at different r.h. There was a lag phase in the initial stage of exposure followed by an exponential decrease in the number of survivors with time, although no lag phase was observed with one strain. Inactivation rates increased with increasing exposure r.h. while no significant inactivation was attained at a r.h. of 50% or below. The conditioning r.h. influenced the duration of the lag phase. The D‐values (decimal reduction time) in the logarithmic phase varied roughly in inverse proportion to the ozone concentration.
Effect of chlorine dioxide on selected membrane functions of Escherichia coli
Authors: Berg J. D. , Roberts P. V. , Matin A.
Published: March 2008

The mode of action of chlorine dioxide on Escherichia coli was assessed by studying outer membrane permeability to macromolecules and potassium, and observing effects on respiration. The results indicate that gross cellular damage involving significant leakage of intracellular macromolecules does not occur. There was a substantial efflux of potassium, however, and respiration was inhibited even at sublethal doses. It was concluded that the inhibition of respiration, which could be due to the damage to the cell envelope, was not the primary lethal event. Observations of the efflux of K+ strongly implicate the loss of permeability control as the primary lethal event at the physiological level, with nonspecific oxidative damage to the outer membrane leading to the destruction of the trans‐membrane ionic gradient.
Detection and enumeration of Listeria monocytogenes in a sewage treatment plant in Iraq
Authors: Al‐ghazali M. R. , Al‐azawi Salwa K.
Published: March 2008

Listeria monocytogenes was isolated from a sewage treatment plant in Baghdad, Iraq, at all stages of treatment. The treatment processes did not yield a sewage sludge cake or a final discharge free of listerias. The agricultural practice of using such sewage products as fertilizers could become a route of spreading the organism in Iraq, particularly by infecting animals that consume vegetation in fields spread with such sewage. Dewatering of sewage reduced the number of L. monocytogenes but long periods of exposure to sun would be needed to obtain a ‘safe’ sewage sludge cake.
A note on physiological characteristics and genetic relatedness of a fast‐growing Rhizobium from stem nodule of Aeschynomene aspera L
Authors: Chakrabarti S. K. , Mishra A. K. , Chakrabartty P. K.
Published: March 2008

A fast‐growing Rhizobium strain was isolated from a stem nodule of Aeschynomene aspera and was characterized by standard laboratory tests, nodulation, nutritional and carbohydrate utilization patterns. Its relationship to other members of Rhizobium was studied by DNA homology tests which suggest it cannot be classified as any known species of Rhizobium.
Purification and characterization of subtilisin inhibitors ‘Marinostatin’ produced by marine Alteromonas sp.
Authors: Imada Chiaki , Maeda Masachika , Hara Saburo , Taga Nobuo , Simidu Usio
Published: March 2008

The four novel peptide subtilisin inhibitors, which have been named Marinostatin B‐1, B‐2, C‐1 and C‐2, were purified from the culture supernatant fluid of a marine bacterium, Alteromonas sp. A combination of Diaion HP‐20 and CM‐cellulofine ion exchange column chromatographies, Sephadex G‐25 gel filtration and preparative high performance liquid chromatography (HPLC) were employed. Final preparations gave a single peak on HPLC. The molecular weights by gel filtration of Marinostatin B‐1 and C‐1 were estimated to be 1500, and those of B‐2 and C‐2 were 1700. All the inhibitors were stable in acidic (pH range 4–6) but less stable in alkaline solutions (pH 10). The metal ions Co2+ and Fe2+ repressed the inhibitory activity by 30 and 20%, respectively. The four inhibitors had inhibitory effects on serine proteases like α‐chymotrypsin.
Scaled‐up production and purification ofClostridium perfringenstype A enterotoxin
Authors: Reynolds D. , Tranter H. S. , HAMBLETON P.
Published: March 2008

Methods for small‐scale production ofClostridium perfringenstype A enterotoxin were unsuitable for large‐scale culture of this organism. Rapid, efficient harvesting of 40 1 batch culture of Cl.perfringenswas achieved by tangential flow micro‐filtration with the Millipore Pellicon cassette system. Enterotoxin‐containing extracts were prepared by passing concentrated suspensions of the harvested cells through a French pressure cell. The overall yield of purified enterotoxin was 38·8%. The toxin gave a single band on native polyacrylamide gels but formed high molecular weight aggregates in the presence of sodium dodecyl sulphate. These aggregates frequently occurred during storage of non‐sterile enterotoxin preparations but could be separated from the monomer toxin by gel filtration on Sephadex G‐100. Purified monomer enterotoxin had biological activities of 119·3μg/kg mouse lethal dose when injected intraperitoneally and 3333 capillary permeability increasing units/mg protein in guinea pig skin. Thirtyμgof the enterotoxin caused fluid accumulation in ligated rabbit ileal loops. Aggregated enterotoxin had no demonstrable biological or immunological activity.
Selective inhibitors for continuous non‐axenic hydrogen production by Rhodobacter capsulatus
Authors: Liessens J. , Verstraete W.
Published: March 2008

To produce H2 continuously by photosynthetically grown Rhodobacter capsulatus in non‐axenic anaerobic reactors, the interaction between the phototroph and possible contaminants was studied and the ecological competitiveness of the Rhodobacter spp. in nitrogen‐limited conditions was determined. Experimental test runs showed that blue‐green and green algae, sulphate‐reducing, acetogenic and methanogenic bacteria significantly interfere with the net amounts of H2 produced by photobacteria. Therefore, inhibitors to control the growth of those contaminants selectively were screened. By applying a combination of chloroxuron (10mg/l) and cycloheximide (10mg/l) against algae, isohumulones (30 bitterunits/l) and molyb‐date (0.5g/l) against sulphate‐reducing bacteria and isohumulones and chloroform (10 mg/l) against acetogens and methanogens, photoreactors could be operated in a non‐axenic way and continued to produce hydrogen gas at rates depending on the feed quality varying from 333 to 676 ml H2l reactor/d, for a period of 116d without apparent interference from other microbial contaminants. These findings have a considerable potential for facilitating the isolation of organo‐phototrophs and the production of H2 by these bacteria.
Detection of cellulolytic fungi by using Congo red as an indicator: a comparative study with the dinitrosalicyclic acid reagent method
Authors: Sazci A. , Erenler K. , Radford A.
Published: March 2008

Cellulolytic fungi can easily be screened within 2 d for the production of cellulolytic enzymes by staining with Congo red, or by measuring the amount of reducing sugar (glucose) produced with the dinitrosalicyclic acid reagent method. Endoglucanase activity is visible in carboxymethyl cellulose agar plates after staining with Congo red, and fixing with HCL or NaOH. This method is essentially based on the interaction of Congo red with intact β‐(1‐4)‐D‐glucans in carboxymethyl cellulose. Endoglucanase and exoglucanase activities of cellulases are quantitatively measured with the dinitrosalicyclic acid reagent method. The enzymatic activity detected with Congo red is compared with that obtained by the dinitrosalicyclic acid reagent method.
Occurrence of plant hormone (cytokinin)‐producing bacteria in the sea
Authors: Maruyama A. , Maeda M. , Simidu U.
Published: March 2008

Plant hormones, which are considered to be cytokinins, were detected in the culture media of marine bacteria using the Amaranthus bioassay method. The proportion of cytokinin‐producing bacteria to total microbes tested was higher in sediments (45–55%) than in seawater (5–15%). The amount of cytokinin‐like substances in the culture media was estimated as 0.05–0.30 μg of zeatin equivalents/l. Thin layer chromatography analysis using the soybean callus bioassay method suggested that the active substance produced by one of these bacteria was isopentenyladenine or its riboside. Taxonomic examination of the cytokinin‐producing bacteria showed that the production of the hormone was not specific to any genus. A possible role of cytokinins produced by sediment bacteria on the development of red tide is discussed.
Degradation of isolated grass mesophyll, epidermis and fibre cell walls in the rumen and by cellulolytic rumen bacteria in axenic culture
Authors: Chesson A. , Stewart C. S. , Dalgarno Karen , King T. P.
Published: March 2008

The degradation of cell walls of mesophyll, epidermis and fibre cells isolated from leaves of perennial and Italian ryegrass within the sheep rumen or by selected strains of rumen bacteria in vitro, was followed by estimation of dry matter loss, or loss of neutral sugar residues. Primary cell walls (mesophyll and epidermis) were fully degraded within 12 h in the rumen, while the more heavily lignified fibre cell walls showed only a 40% loss of dry matter over the same period. Neutral sugar residues were lost at a common rate from walls of all three cell types. Incubation of cell walls with cellulolytic bacteria showed that the extent to which cell walls were attacked was constantly ordered (epidermis > mesophyll > fibre). The rate of degradation of cell walls was less in axenic culture than within the rumen. Greatest weight losses were produced by Ruminococcus albus, followed by Bacteroides succinogenes, with Ruminococcus flavefaciens effecting the least change, regardless of the nature of the cell wall provided as a substrate. Xylose was more readily lost from primary cell walls than glucose during the early stages of attack, but both were lost at a common rate from fibre cell walls. Dry matter losses produced by the hemicellulolytic strain, Bacteroides ruminocola, were limited even after extended incubation. Electron microscopy indicated that R. albus was less commonly attached to cell walls than were the other cellulolytic strains, although evidence of capsular material was present. Bacteroides succinogenes was seen with an extensive capsule which enveloped clusters of cells, forming micro‐colonies in association with the plant cell wall. Vesicle‐like structures, commonly associated with the cellulolytic bacteria R. albus and B. succinogenes, were found on comparatively few occasions in this study.
The effect of artificially inoculated antagonistic bacteria on the prevalence of take‐all disease of wheat in field experiments
Authors: Capper Arvil L. , Campbell R.
Published: March 2008

Bacteria from wheat field soils were screened in vitro and in glasshouse experiments for antagonism to the take‐all fungus Gaeumannomyces graminis var. tritici. Field experiments to test the ability of the selected bacteria to reduce naturally occurring take‐all disease gave variable results. In the most successful series the yield of spring wheat was doubled and the amount of disease reduced to half the unprotected control value. Failure to show disease control seemed to be due either to a naturally low incidence of the disease on the trial sites or to especially dry soil conditions.
The effect of citric acid on growth of proteolytic strains of Clostridium botulinum
Authors: Graham Ann F. , Lund Barbara M.
Published: March 2008

In strictly anaerobic conditions in a culture medium adjusted to pH 5·2 with HCl and incubated at 30°C, inocula containing < 10 vegetative bacteria of Clostridium botulinum ZK3 (type A) multiplied to give > 108 bacteria per ml in 3 d. Growth from an inoculum of between 10 and 100 spores occurred after a delay of 10–20 weeks. Citric acid concentrations of 10–50 mmol/l at pH 5·2 inhibited growth from both vegetative bacteria and spore inocula, a concentration of 50 mmol/l increasing the number of vegetative bacteria or of spores required to produce growth by a factor of approximately 106. The citric acid also reduced the concentration of free Ca2+ in the medium. The inhibitory effect of citric acid on vegetative bacteria at pH 5·2 could be prevented by the addition of Ca2+ or Mg2+ and greatly reduced by Fe2+ and Mn2+. The addition of Ca2+, but not of the remaining divalent metal ions, restored the concentration of free Ca2+ in the medium to that in the citrate‐free medium. The inhibitory effect of citric acid on growth from a spore inoculum was only partially prevented by Ca2+. Citric acid (50 mmol/l) did not inhibit growth of strain ZK3 at pH 6 despite the greater chelating activity of citrate at pH 6 than at pH 5·2. The effect of citric acid and Ca2+ at pH 5·2 on vegetative bacteria of strains VL1 (type A) and 2346 and B6 (proteolytic type B) was similar to that on strain ZK3.
Stoichiometry of glucose and starch splitting by strains of amylolytic bacteria from the rumen and anaerobic digester
Authors: Marounek M. , Bartos S.
Published: March 2008

The stoichiometry of glucose and starch splitting by the amylolytic bacteria Streptococcus bovis, Selenomonas ruminantium, Butyrivibrio fibrisolvens, Eubacterium ruminantium and Clostridium sp. was followed. There were many differences in the ratios of metabolites and in growth yields, as well as in the cell composition, between the growth on glucose and starch. The bacteria employ different nutritional strategies with respect to both energy sources.
Bacterial sources of putrescine and cadaverine in chill stored vacuum‐packaged beef
Authors: Dainty R. H. , Edwards R. A. , Hibbard C. M. , Ramantanis S. V.
Published: March 2008

Of the meat strains of streptobacteria, leuconostocs, Enterobacteriaceae and Brochothrix thermosphacta tested, only Hafnia alvei and Serratia liquefaciens showed diamine‐producing potential during growth in pure culture on beef stored in vacuum packs at 1°C. Both organisms produced cadaverine at concentrations similar to those reported previously in naturally contaminated beef stored under the same conditions. Putrescine concentrations produced by the two organisms, however, were an order of magnitude lower. During the growth on beef of either H. alvei or S. liquefaciens in mixed culture with arginine‐utilizing strains of streptobacteria, putrescine as well as cadaverine concentrations were similar to those detected in naturally contaminated samples.