bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative sensitivity to antibiotics and biocides of methicillin‐resistant Staphylococcus aureus strains isolated from Saudi Arabia and Great Britain
Authors: Al‐Masaudi S.B. , Russell A.D. , Day M.J.
Published: March 2008

S.B. AL‐MASAUDI, A.D. RUSSELL AND M.J. DAY. 1991. Methicillin‐resistant Staphylococcus aureus (MRSA) isolated in Saudi Arabia and Great Britain were examined for susceptibility to antibiotics and biocides. The strains differed in their sensitivity patterns. None of the Saudi strains showed resistance to propamidine isethionate, but most of the British gentamicin methicillin‐resistant Staph. aureus (GMRSA) strains were highly resistant to this compound and to some other nucleic acid‐binding (NAB) compounds. Both groups showed a low level of resistance towards quaternary ammonium compounds (QACs), but resistance to these compounds was not associated with resistance to gentamicin in the Saudi strains. The aminoglycoside‐resistant determinants were non‐conjugative in these strains. Natural MRSA strains were good recipients for pWG613, but transferred this plasmid in reciprocal crosses at significantly lower rates.
Evaluation of the RAPID ID 32A system for the identification of Bacteroides fragilis and related organisms
Authors: Jenkins Stephanie A. , Drucker D.B. , Keaney Maeve G.L. , Ganguli Leela A.
Published: March 2008

S.A. JENKINS, D.B. DRUCKER, M.G.L. KEANEY AND L.A. GANGULI. 1991. This study evaluated the ability of a rapid identification system for anaerobic bacteria. ATB 32A, now renamed RAPID ID 32A (API‐bioMérieux UK Ltd., Basingstoke), to identify accurately 74 strains of the ‘B. fragilis group’. ATB 32A identified correctly 78.4% of strains to species level, without supplemental tests. The percentage of strains identified to species level rose to 94.6% when a supplementary test (advised by bioMérieux) for catalase production was used to differentiate between Bacteroides ovatus and Bacteroides uniformis. RAPID ID 32A is a rapid, accurate method for the identification of members of the ‘B. fragilis group’ isolated within a routine clinical laboratory.
Plasmid profiles and curing of plasmids in Lactobacillus plantarum strains isolated from green olive fermentations
Authors: Ruiz‐Barba J.L. , Piard J.C. , Jiménez‐Díaz R.
Published: March 2008

J.L. RUIZ‐BARBA, J.C. PIARD AND R. JIMENEZ‐DIAZ. 1991. Plasmid profiles of 35 Lactobacillus plantarum strains isolated from different green olive fermentors were obtained. A large number of plasmids in the CCC form (from 5 to 16) were present in all the tested strains as confirmed by a second dimension electrophoresis of DNA. These plasmids, all of which remain cryptic, ranged from 2.0 to 68 kb in size. Novobiocin, sodium dodecyl sulphate and ethidium bromide were used as plasmid‐curing agents but only novobiocin induced loss of extrachromosomal DNA at a high frequency in these strains.
Mercuric reductase activity in the adaptation to cationic mercury, phenyl mercuric acetate and multiple antibiotics of a Gram‐negative population isolated from an aerobic fixed‐bed reactor
Authors: Henriette Caroline , Petitdemange E. , Raval G. , Gay R.
Published: March 2008

C. HENRIETTE, E. PETITDEMANGE, G. RAVAL AND R. GAY. 1991. Eighty‐eight strains, isolated from an aerobic fixed‐bed reactor and identified to the genus level, were examined for resistance to 21 antibiotics, cationic mercury and phenylmercuric acetate. All except three were able to grow on Mueller‐Hinton agar plates containing 8 μg/ml mercuric chloride, but only 42 exhibited a mercuric reductase and an organomercurial lyase activity. Furthermore, 82 of them were multiply‐antibiotic resistant, whereas no positive correlation between this property and cationic mercury volatilization capacity was found. It was concluded that this bacterial community‐adapted response to these selective agents, which has been most often shown to be mediated by R plasmids, was the result of two independent phenomena. Moreover, the high percentage of multiple antibiotic and mercury resistance found in this population suggested that simultaneous selections occurred on filters of bacteria which exhibited mucoid colonies and tolerance to these two categories of stress agents.
Typing of Proteus mirabilis from clinical sources by computerized analysis of electrophoretic protein patterns
Authors: Holmes B. , Costas M. , Wood A.C.
Published: March 2008

B. HOLMES, M. COSTAS AND A.C. WOOD. 1991. Seventy‐five strains of Proteus mirabilis (mainly of human origin) were characterized by one‐dimensional SDS‐PAGE of cellular proteins. The strains came from various countries; 24 were from urine, 17 from faeces (including one from a dog and one from a monkey), 12 from the respiratory tract (including nine from sputum), four from a cerebral abscess, 12 from miscellaneous sources and six from unknown sources. The protein patterns, which contained 45 to 50 discrete bands, were highly reproducible. The patterns of the 75 P. mirabilis cultures plus those of the type strains of six Proteus and Providencia species were used as the basis for two numerical analyses. In the first, which included all the protein bands, the P. mirabilis cultures formed nine clusters at the 85% S level. In the second analysis, in which the principal protein bands (in the 34.0–44.6 kDa range) were excluded, 74 of the 75 cultures of P. mirabilis formed a single cluster at the 77% S level distinct from the six Proteus and Providencia reference strains. The P. mirabilis strain which failed to cluster with the others had a background band pattern typical of the species in the lower molecular weight region but appeared to be less typical in the heavier bands. It is concluded that high resolution PAGE combined with computerized analysis of protein patterns provides the basis for typing clinical strains of P. mirabilis. Reference strains of each of the nine PAGE types identified are available from NCTC for inclusion in future studies.
The dispersal of bacteria from leaf surfaces by water splash
Authors: Butterworth Julie , McCartney H.A.
Published: March 2008

J. BUTTERWORTH AND H.A. McCARTNEY. 1991. Advances in the techniques of genetic engineering have made possible the use of genetically manipulated micro‐organisms (GMOs) for the control of pests and diseases. Before GMOs can be widely used in agriculture, however, their fate after release must be understood. Dispersal of released GMOs will have an important influence on their action or survival under field conditions. The object of this study was to quantify the efficiency of rain as a means of removing and disseminating such micro‐organisms from foliar crop surfaces.

Spontaneous mutants of three species of bacteria (Pseudomonas syringae, Klebsiella planticola and Bacillus subtilis), resistant to the antibiotic rifampicin, were sprayed on two plant species, french bean, Phaseolus vulgaris, and oilseed rape, Brassica napus. The leaves from the plants were then exposed to artificial rain and splash droplets generated by the impact on the leaves were collected on selective nutrient agar in Petri dishes and in sterile glass 28 ml screw‐capped bottles. The bacterial content of the splashed drops was assessed, as was the content of the water which ran off the leaf surfaces. Comparisons of the numbers of bacteria removed from the leaves with the numbers applied prior to splashing show that rainfall can be a very efficient means of removing bacteria from foliar surfaces, but that most of the removed bacteria run off to the soil. Only a small proportion was splashed relatively short distances from the source.
Glucose and lactate catabolism by bacteria of the pig large intestine and sheep rumen as assessed by 13C nuclear magnetic resonance
Authors: Stevani J. , Grivet J.P. , Hannequart G. , Durand M.
Published: March 2008

J. STEVANI, J.P. GRIVET, G. HANNEQUART AND M. DURAND. 1991. The fermentation of [1‐13C] glucose and [3‐13C] lactate by bacteria isolated from sheep rumen and pig large intestine was compared by the nuclear magnetic resonance (NMR) technique. Washed cell suspensions were incubated directly in the NMR spectrometer and spectra were recorded every 10 min after injection of the labelled substrates. The results showed large differences in the fermentation patterns between rumen and hindgut bacteria. The latter pattern indicated a greater ability for formation and fermentation of lactate than that of the rumen. Moreover, with both substrates the amount of propionate formed via the acrylate pathway was always greater with hindgut than with rumen bacteria, 50% and 20% of the total, respectively.

INTRODUCTION

Dietary polysaccharides and oligosaccharides which are not digested by intestinal enzymes enter the large intestine (or hindgur) where they are fermented by the microflora. This anaerobic process is similar to that in the rumen (Miller & Wolin 1979; Bergman 1990) and leads to the formation of similar short chain fatty acids (SCFA) (one to seven carbon atoms). The microbial metabolism of the rumen ecosystem, which has been extensively studied is often taken as a model for hindgut bacterial metabolism. However, some discrepancies have been identified (Wolin & Miller 1983; Demeyer et al. 1989; Henderson & Demeyer 1989). They mainly concern interspecies transfer of hydrogen but also the biochemistry of propionate formation. As pointed out by Wolin & Miller (1983) the fermentative pathways of large intestinal microflora and especially the status of lactate as a possible fermentation intermediate are still uncertain. However, in humans it is considered that lactate may be an important intermediate of colonic bacteria particularly in the right colon in which fermentable carbohydrates are abundant or in in vitro cultures of starchy substances (G.T. Macfarlane, personal communication).
Formulation of a flowable liquid concentrate of Bacillus thuringiensis serotype H‐14 spores and crystals as mosquito larvicide
Authors: Ejiofor A.O. , Okafor N.
Published: March 2008

A.O. EJIOFOR AND N. OKAFOR. 1991. Bacillus thuringiensis serotype H‐14 spores and crystals, produced in 5 1 fermenters, were centrifuged and resuspended in emulsified palm olein to give 3.2 × 1011 colony forming units (cfu)/ml. The suspension was mixed with a cassava—molasses—palm olein—charcoal (CMPC‐2) mixture which served as the carrier, adhesive, dispersant and protectant. The final concentration of the formulation was 3.2 × 109 cfu/ml. The lethal concentrations capable of killing 50% of the test population (LC50) of CMPC‐2 during 0, 1 and 2 years of storage at 32 ± 4.C were 0.056, 0.058 and 0.058 mg/ml respectively as against 0.054, 0.051 and 0.054 mg/ml for the Institut Pasteur Standard—1978 (IPS‐78) during the corresponding period. The2 tests showed that the results were homogeneous at P= 0.05. The relative potencies of the preparation were 964.3, 879.3 and 931 International toxic units (ITU) Aedes aegypti as compared with the 1000 ITU assigned to IPS‐78. At 95% confidence limits there was no significant difference between the potencies of CMPC‐2 and IPS‐78. Field tests showed that CMPC‐2 provided between 87.5 and 100% control of natural populations of Aedes spp. and Cutex spp. Sedimentation tests showed that CMPC‐2 settled markedly during storage. This, therefore, required that the product be thoroughly shaken before use.
Isolation and characterization of salinity resistant mutant of a nitrogen‐fixing cyanobacterium, Anabaena doliolum
Authors: Singh D.V. , Tripathi A.K. , Kumar H.D.
Published: March 2008

D.V. SINGH. A.K. TRIPATHI AND H.D. KUMAR. 1991. Sodium chloride, up to 20 mmol/l concentration, had a positive effect on acetylene reducing activity and photosynthetic oxygen evolution of a paddy field cyanobacterium, Anabaena doliolum. Beyond 20 mmol/l level of salinity adverse effects appeared. A mutant resistant to 200 mmol/l NaCl was isolated by nitrosoguanidine mutagenesis. The mutant, NaCl‐R200, showed about 20–25% more nitrogenase activity and photosynthetic oxygen evolution than the parent. Better capacity of nitrogen fixation and photosynthesis possibly could help the mutant in synthesis of osmotic stabilizer to resist the salinity stress.
The effects of three non‐antibiotic, antimicrobial agents on the surface hydrophobicity of certain micro‐organisms evaluated by different methods
Authors: Jones D.S. , Gorman S.P. , McCafferty D.F. , Woolfson A.D.
Published: March 2008

D.S. JONES, S.P. GORMAN, D.F. MCCAFFERTY AND A.D. WOOLFSON. 1991. The effects of three non‐antibiotic, antimicrobial agents (taurolidine, chlorhexidine acetate and providone‐iodine) on the surface hydrophobicity of the clinical strains Escherichia coli, Staphylococcus saprophyticus, Staphylococcus epidermidis and Candida albicans were examined. Three recognized techniques for hydrophobicity measurements, Bacterial Adherence to Hydrocarbons (BATH), the Salt Aggregation Test (SAT) and Hydrophobic Interaction Chromatography (HIC) were compared. At concentrations reported to interfere with microbial‐epithelial cell adherence, all three agents altered the cell surface hydrophobicity. However, these effects failed to exhibit a uniform relationship. Generally, taurolidine and povidone‐iodine treatments decreased the hydrophobicity of the strains examined whereas chlorhexidine acetate effects depended upon the micro‐organism treated. Subsequently, the exact contribution of altered cell surface hydrophobicity to the reported microbial anti‐adherence effects is unclear. Comparison of the three techniques revealed a better correlation between the results obtained with the BATH test and HIC than the results obtained with the BATH and SAT or SAT and HIC. However, these differences may be due to the inaccuracy associated with the visual assessment of results employed by the SAT.
Competitive dominance of antibiotic‐producing marine bacteria in mixed cultures
Authors: Lemos M.L. , Dopazo C.P. , Toranzo Alicia E. , Barja J.L.
Published: March 2008

M.L. LEMOS. C.P. DOPAZO, ALICIA E. TORANZO AND J. L. BARJA. 1991. Competitive relationships between antibiotic‐producing marine bacteria and other non‐producers were studied in seawater mixed cultures. Producer strains showed a competitive advantage against non‐producers as the latter were inhibited after a short time. Inhibition was also noted in mixed cultures of two producer strains. The inhibitory effect was not observed in a mixed culture with two non‐producers, which indicates that an amensalist interaction occurred between populations of antibiotic‐producing and non‐producing marine bacteria. The results suggest that antibiotics could play an important role in the competitive relationships between marine bacterial populations.
Heterolactic fermentation by a homofermentative Lactobacillus sp. during glucose limitation in anaerobic continuous culture with complete cell recycle
Authors: Borch Elisabeth , Berg H. , Holst O.
Published: March 2008

E. BORCH, H. BERG AND O. HOLST. 1991. The homofermentative Lactobacillus sp. 93 SMRICC 235 was grown anaerobically in batch culture and subsequent continuous culture, with complete cell recycle at pH 6.0 and 25.C, on a semi‐defined medium. During cell recycle culture the biomass was concentrated in the fermenter to a final dry weight of 37 g/1 and a viable count of 10.6 log cfu/ml. The corresponding final values in batch culture were 2.4 g/1 and 9.3 log cfu/ml. A switch from homo‐ to heterolactic fermentation was observed during starvation, due to glucose depletion in the cell recycle culture. High levels of acetate and formate were produced in addition to ethanol. Amino acid profiles of hydrolysed samples showed extensive utilization of amino acids, particularly in cell recycle culture. Sulphide was produced during cell recycle culture. The change from homo‐ to heterolactic fermentation observed during semi‐starvation is likely to affect the properties of lactobacilli as spoilage bacteria of meat and meat products, as well as starter cultures.
Surface characteristics and adhesion of Escherichia coli and Staphylococcus epidermidis
Authors: Gilbert P. , Evans D.J. , Evans E. , Duguid I.G. , Brown M.R.W.
Published: March 2008

Surface hydrophobicity, surface electrokinetic potential and the ability to adhere to nitric‐acid cleansed glass surfaces has been assessed throughout the growth, in batch culture, of Escherichia coli and Staphylococcus epidermidis. In both instances adhesiveness and surface hydrophobicity decreased in early‐ to mid‐exponential phase. Cell surface charge, on the other hand became more electro‐negative for E. coli but electro‐neutral for Staph. epidermidis as the cells proceeded to divide. Adhesiveness correlated directly with surface electronegativity and hydrophobicity for Staph. epidermidis but inversely with surface electro‐negativity for E. coli.
Expression of a β‐galactosidase gene from Clostridium acetobutylicum in Lactococcus lactis subsp. lactis
Authors: Pillidge C.J. , Pearce L.E.
Published: March 2008

A β‐galactosidase gene from Clostridium acetobutylicum NCIB 2951 was expressed after cloning into pSA3 and electroporation into derivatives of Lactococcus lactis subsp. lactis strains H1 and 7962. When the clostridial gene was introduced into a plasmid‐free derivative of the starter‐type Lact. lactis subsp. lactis strain H1, the resulting construct had high β‐galactosidase activity but utilized lactose only slightly faster than the recipient. β‐galactosidase activity in the construct decreased by over 50% if the 63 kb Lac plasmid pDI21 was also present with the β‐galactosidase gene. Growth rates of Lac+ H1 and 7962 derivatives were not affected after introduction of the clostridial β‐galactosidase, even though β‐galactosidase activity in a 7962 construct was more than double that of the wild‐type strain. When pDI21 was electroporated into a plasmid‐free variant of strain 7962, the recombinant had high phospho‐β‐galactosidase activity and a growth rate equal to that of the H1 wild‐type strain. The H1 plasmid‐free strain grew slowly in T5 complex medium, utilized lactose and contained low phospho‐β‐galactosidase activity. We suggest that β‐galactosidase expression can be regulated by the lactose phosphotransferase system‐tagatose pathway and that Lact. lactis subsp. lactis strain H1 has an inefficient permease for lactose and contains chromosomally‐encoded phospho‐β‐galactosidase genes.
Haemagglutinins and fimbriae of soft rot Erwinias
Authors: Wallace Anne , Pérombelon M.C.M.
Published: March 2008

A. WALLACE AND M.C.M. PÉROMBELON. 1992. Strains of phytopathogenic soft rot Erwinia spp. were examined for haemagglutinin (HA) production. Mannose‐sensitive HA was found only in five of 15 strains of E. carotovora subsp. carotovora. Mannose‐resistant HA (MRHA) was found in 12 of 15 strains of E.c. carotovora, ten of 13 strains of E.c. subsp. atroseptica and the single strain of E.c. subsp. betavasculorum, as well as all seven strains of E. chrysanthemi. MRHA, detectable only in a microtitre tray HA assay was of either broad‐ or narrow‐spectrum activity when examined against blood of seven different animal species and could be inhibited by the β‐galactoside asialofetuin. Fimbriae of ca 10 nm diameter were found on MRHA+ bacteria of E.c. carotovora and E.c. atroseptica.
Lipids of Arthrobacter siderocapsulatus
Authors: Amadi E.N. , Alderson Grace
Published: March 2008

E.N. AMADI AND G. ALDERSON. 1992. The results of lipid studies confirm that Arthrobacter siderocapsulatus is not a member of the genus Arthrobacter. Further studies are required to determine the taxonomic status of these Gram‐negative bacteria.
Production of α‐amylase by Myxococcus coralloides D
Authors: Fárez‐Vidal M. Esther , Fernandez‐Vivas Antonia , Arias José M.
Published: March 2008

M.E. FÁREZ‐VIDAL, A. FERNANDEZ‐VIVAS AND J.M. ARIAS. 1992. Myxococcus coralloides D secreted amylase into a liquid growth medium containing 1% starch. Amylase activity was highest at the end of the exponential growth phase. Of the nitrogen sources tested, the greatest growth and amylase production were obtained with trypticase peptone, casitone, probion L and probion F. When starch was replaced by other carbon sources, amylase production was reduced; trisaccharide produced better results than disaccharide while monosaccharide reduced amylase production to basal levels. Maltose repressed amylase production. Amylase production was greater in stirred flasks, at pH between 6.5 and 7.5, and at temperatures from 28d̀C to 33d̀C. The activity of partially purified M. coralloides D amylase was used to determine the products released from the hydrolysis of starch with thin‐layer chromatography, paper chromatography and nuclear magnetic resonance. These products were maltose and glucose and limit dextrins.
Use of polyvalent phage for reduction of streptomycetes on soil dilution plates
Authors: Kurtböke D.I. , Chen C.F. , Williams S.T.
Published: March 2008

D.I. KURTBÖKE, C.F. CHEN AND S.T. WILLIAMS. 1992. An isolation method was developed in which prior to inoculation soil suspensions were exposed to suspensions of polyvalent phage isolated to Streptomyces spp. The phage susceptibility of streptomycetes provided a selective means of reducing streptomycetes on isolation plates subsequent to inoculation, and this reduction was persistent after long incubation periods. The efficiency and applicability of the method developed were checked with different samples from a range of sources. The increased chances of development of other genera after the reduction of streptomycetes on soil dilution plates were assessed.
The effect of disinfectants on a geosmin‐producing strain of Streptomyces griseus
Authors: Whitmore T.N. , Denny S.
Published: March 2008

T.N. WHITMORE AND S. DENNY. 1992. This study describes the bactericidal and sporicidal effects of four disinfectants on a geosmin‐producing strain of Streptomyces griseus. The disinfectants investigated were chlorine, chloramine, chlorine dioxide and ozone. Chlorine and chlorine dioxide at concentrations around 1 mg/1 were effective inactivators of both spore and mycelial propagules. Decimation times of less than 1 min were determined in each case. Both growth forms exhibited a high ozone demand, but decimation times resulting from an initial dose of around 2.5 mg/1 were approximately 1/5 min. Monochloramine was comparatively less effective: at a concentration of approximately 1 mg/1 the decimation times for spores and mycelia were 13.8 and 22.7 min, respectively.
Bactericidal activities of lysozyme and aprotinin against Gram‐negative and Gram‐positive bacteria related to their basic character
Authors: Pellegrini A. , Thomas U. , von Fellenberg R. , Wild P.
Published: March 2008

A. PELLEGRINI, U. THOMAS, R. VON FELLENBERG AND P. WILD. 1992. Bactericidal properties of aprotinin, a proteinase inhibitor and possibly a defence molecule in bovine species, and of chicken egg white lysozyme, known as muramidase, were investigated. Incubation of various bacteria in the presence of either aprotinin or lysozyme showed that both proteins killed Gram‐positive as well as Gram‐negative bacteria without addition of complement or EDTA. Denaturation of the two proteins by dithiothreitol did not lead to loss of their bactericidal potency. Electron microscopic examination of Escherichia coli incubated either with lysozyme or aprotinin revealed that the bacterial cytoplasms gradually disintegrated. Both aprotinin and lysozyme were demonstrated within the affected cytoplasm by immunogold labelling. The results suggest that the bactericidal potency of lysozyme is not only due to muramidase activity but also to its cationic and hydrophobic properties. The bactericidal activity of aprotinin is probably also related to both these properties rather than to its activity as proteinase inhibitor.
Selection of cell wall antigens for the rapid detection of bacteria by immunological methods
Authors: Labadie J. , Desnier I.
Published: March 2008

J. LABADIE AND I. DESNIER. 1992. Some proteins extracted from the cell wall of Gram‐positive and Gram‐negative bacteria that affect the time for which meat can be stored are antigens produced by the strains from our laboratory collection or from field samples. Moreover, the rapid detection of bacteria (within 8 h for Gram‐positive or 5 h for Gram‐negative) that influence the quality of meat is made possible by immunochemical techniques such as ELISA or by introducing simultaneous detection of these antigens, as no cross‐reactions have been observed.
A second serogroup of Legionella erythra serologically indistinguishable from Legionella rubrilucens
Authors: Saunders N.A. , Doshi Nivedita , Harrison T.G.
Published: March 2008

N.A. SAUNDERS, N. DOSHI AND T.G. HARRISON. 1992. Twenty‐two red‐autofluorescent Legionella strains were identified serologically as either Legionella rubrilucens or L. erythra. A rRNA probe was used for restriction fragment length polymorphism (RFLP) analysis of the strains and the patterns generated were used as an additional method of identifying the strains to species level. In two instances strains which were identified as L. rubrilucens by serology appeared to belong to the species L. erythra by RFLP analysis. This apparent contradiction was resolved by measurements of DNA/DNA homology which confirmed the existence of a second serogroup of L. erythra serologically indistinguishable from L. rubrilucens.
Use of the polymerase chain reaction and oligonucleotide probes for the rapid detection and identification of Carnobacterium species from meat
Authors: Brooks Joy L. , Moore Andrea S. , Patchett R.A. , Collins M. D. , Kroll R.G.
Published: March 2008

J.L. BROOKS, A.S. MOORE, R.A. PATCHETT, M. D. COLLINS AND R.G. KROLL. 1992. The polymerase chain reaction (PCR) was used selectively to amplify specific rDNA sequences of Carnobacterium divergens, C. mobile, C. piscicola and C. gallinarum in purified DNA extracts, crude cell lysates and food samples. The PCR products were visualized by agarose gel electrophoresis and identified, at species level, by hybridization reactions with three specific oligonucleotide probes for C. divergens, C. mobile and C. piscicola/C. gallinarum designed from 16S rRNA sequence data. The PCR was sufficiently sensitive to amplify DNA from a single bacterium to detectable levels after 30 cycles of amplification. Both radioactive (32P) and non‐radioactive alkaline phosphatase labelled probes was able to detect the PCR products. Detection was highly specific and the probes did not hybridize with DNA samples from any other of the bacterial species tested. These methods enabled the rapid and specific detection and identification of carnobacteria from pure cultures and samples of meat.
Numerical classification and identification of Aeromonas genospecies
Authors: Kämpfer P. , Altwegg M.
Published: March 2008

P. KÄMPFER AND M. ALTWEGG. 1992. A total of 176 Aeromonas strains representing all currently characterized genospecies were tested for 329 biochemical characters. Overall similarities of all strains were determined by numerical taxonomic techniques, the UPGMA algorithm and the SSM and the SJ coefficients as measures of similarity. Sixteen clusters (two or more strains) and seven unclustered strains were recovered at the 93.5% similarity level (SSM). Genospecies 1, 4, 5, 6, 7, 9, 12 and 13 were largely represented by single phena, whereas strains of genospecies 2 and 3 were found in closely‐related phena. Strains belonging to genospecies 8 formed two distinct biotypes. Strains belonging to genospecies 11 formed a subcluster within a cluster representing different genospecies. In general, similar groupings were obtained with the Jaccard coefficient at a similarity level of 80.0% (SJ) with minor changes in the definition of clusters. The phenetic data showed good correlation with the taxa defined by DNA/DNA hybridization and those obtained by multilocus enzyme analysis. For all genospecies (independent from cluster assignment) 30 diagnostic characters were selected to construct a matrix for probabilistic identification. The correct identification rate of the matrix was 71.51% taking a Willcox probability < 0.99, and 83.7% taking a Willcox probability > 0.9 as identification threshold levels.
Neurospora species in bakeries
Authors: Yassin S. , Wheals A.
Published: March 2008

S. YASSIN AND A. WHEALS. 1992. Neurospora species may occur as spoilage organisms in bakeries and bakery products. A survey of two bakeries over a 4 month period produced 315 individually isolated strains which were characterized with respect to six features: conidial colour, protoperitheciality, mating type and percentage dark‐coloured (fertile) ascospores in crosses with type specimens of Neurospora crassa, N. sitophila and N. intermedia. We concluded that (i) N: crassa of both mating types was by far the most abundant but N. sitophila and N. intermedia were also represented; (ii) conidial colour was not a good species criterion; (iii) the percentage of fertile ascospores produced in crosses with several type specimens provided a reliable and simple species indicator; (iv) identification of individuals based on these six characteristics suggested that a large number of genetically different organisms were present in the collection; and (v) bakery infection was not due to endemic contamination in the bakery or in raw materials but from repeated external infection, perhaps on contaminated returned goods.
Fungal and actinomycete spore aerosols measured at different humidities with an aerodynamic particle sizer
Authors: Madelin T.M. , Johnson H.E.
Published: March 2008

T.M. MADELIN AND H.E. JOHNSON. 1992. An aerodynamic particle sizer (APS) that uses laser Doppler velocimetry was used to determine aerodynamic diameters of spores of fungal and thermophilic actinomycete species common in mouldy hay, acrosolized at different humidities and temperatures. Results were compared with those obtained from inertial impaction in a cascade impactor. The APS gave slightly smaller measurements than the cascade impactor. Both methods gave aerodynamic diameters generally slightly smaller than the average spore dimensions observed on cascade impactor slides with a microscope. The latter measurements were less than axial dimensions given in the literature. Brief passage of spores through air at 95% relative humidity (RH) and 38°C, compared with 40% RH and 20°C, caused an immediate increase in their aerodynamic diameter and the breaking of chains of spores. Cultures maintained at 75% RH and aerosolized at 98% RH similarly produced larger spore particles than those passed through dry air. These findings have implications for mould‐induced asthma and allergic alveolitis since they relate to physical behaviour of airborne spores and particle deposition sites in the lung.
The effect of dilution rate and pH on biomass and proteinase production by Micrococcus sedentarius grown in continuous culture
Authors: Holland K.T. , Marshall J. , Taylor D.
Published: March 2008

K.T. HOLLAND, J. MARSHALL AND D. TAYLOR. 1992. Micrococcus sedentarius, an organism associated with pitted keratolysis, produced two proteinases in culture supernatant fluids, as shown by non‐denaturing PAGE with overlaying with a casein substrate. A mixture had optimal activity at pH 10 with azocasein substrate. At pH 7.1 and 8.1 in continuous culture with varying dilution rates high proteinase production occurred at relative specific growth rates (μrels) 0.39 and 0.77 and biomass concentrations decreased with increasing dilution rate. One proteinase was constitutive and varied little in production with different growth rates. The other proteinase was under control with high production at low growth rates and no production at high growth rates. With varying pH at μrels, 0.39 and 0.77 maximum biomass concentration and proteinase production occurred between pH 8.0 and 9.0 as did the highest specific growth rate. These results support the hypothesis that Mic. sedentarus produces pitting in the stratum corneum when the skin is hydrated and the pH rises above neutrality.
Bacterial growth in plant tissue culture media
Authors: Leifert C. , Waites W.M.
Published: March 2008

C. LEIFERT AND W.M. WAITES. 1992. When Murashige and Skoog's liquid plant medium was inoculated with 10 different bacterial species in the absence of plants only Bacillus subtilis showed significant growth. The numbers of Lactobacillus plantarum, Pseudomonas maltophilia, Erwinia carotovora and Staphylococcus saprophyticus decreased rapidly and were not detected at 28 d.

Bacillus subtilis, Lact. plantarum, Ps. maltophilia, Erw. carotovora and Staph. saprophyticus grew and persisted in the same medium in the presence of Delphinium plants, while only Lact. plantarum and Erw. carotovora grew and persisted in the presence of Hemerocallis plants.

Hemerocallis plants lowered the pH of media from 5.6 to about 3.9 while Delphinium plants increased it to about 5.9 within 7 d after subculturing on fresh media. The pH drop in Hemerocallis media is thought to prevent the growth and persistence of bacteria such as B. subtilis, Staph. saprophyticus and Ps. maltophilia, which were found to be more sensitive to low pH than Lact. plantarum and Erw. carotovora. Bacterial growth in the medium altered the pH, reduced the plant growth and/or resulted in plant death.
Differentiation between thermophilic Campylobacter species by species‐specific antibodies
Authors: Griffiths P.L. , Moreno G.S. , Park R.W. A.
Published: March 2008

P.L. GRIFFITHS. G.S. MORENO AND R.W. A. PARK. 1992. The four species of thermophilic camplyobacters, Campylobacter jejuni, C. coli, C. upsaliensis and C. lari, are difficult to distinguish from each other because of their lack of reactivity in many conventional biochemical and physiological tests. Those tests which do discriminate sometimes give discordant results. Species‐specific antibody preparations (APs), capable of discriminating between the thermophilic campylobacter species by dot‐ELISA, were raised by inoculation of mice with partially purified membrane protein. The APs produced were absorbed with cells of cross‐reactive species and tested by dot‐ELISA against reference and natural strains, the identities of which were confirmed by DNA/DNA hybridization. The results showed that such APs could be useful as an alternative to DNA/DNA hybridization for rapid species identification, for example in epidemiological surveys. Western blotting experiments with the APs showed that the specificity of the antibodies was not due to a single antigen.
Xylanase production by Thermomonospora curvata
Authors: Stutzenberger F.J. , Bodine A.B.
Published: March 2008

F.J. STUTZENBERGER AND A.B. BODINE. 1992. The thermophilic actinomycete, Thermomonospora curvata, produced <1 xylanase U/mg dry cell weight during growth in minimal medium with soluble sugars, 3–7 U/mg on purified xylan or cellulose and 28 U/mg on cotton fibres. The optimal growth temperature for xylanase production was 55°C. Cell‐bound xylanase decreased from about 30% of total activity in early culture to about 2% in stationary phase. Fractionation of extracellular proteins by isoelectric focusing and size exclusion chromatography yielded three endoxylanases (XI, X2 and X3) with pI and mol. wts of pH 4.2, 7.1 and 8.4 and 36, 19 and 15 kDa respectively. X1, X2 and X3 had similar pH optima (7.8, 7.2 and 6.8) and Km for xylan (2.5, 1.4 and 2.0 mg/ml) respectively, but differed in their thermostability; half‐lives at 75°C were 21 h for X1, 151 h for X2 and 302 h for X3.
Experimental enzyme‐linked amperometric immunosensors for the detection of salmonellas in foods
Authors: Brooks Joy L. , Mirhabibollahi B. , Kroll R.G.
Published: March 2008

Two enzyme‐linked amperometric immunosensors specific for salmonellas were developed as rapid methods for quantifying and detecting these organisms in pure cultures and foods. Both used alkaline phosphatase as the enzyme reporter molecule but one system used phenyl phosphate as the substrate followed by the electrochemical detection of phenol at a polarized platinum electrode. The other system incorporated an enzyme amplification step and relied on the electrochemical detection of a reduced mediator, ferrocyanide. Both assays were rapid (4 h) and specific and generated salmonella‐dependent signals above 104 cfu/ml (phenyl phosphate system) or 105 cfu/ml (enzyme amplified system) in pure cultures and samples of several foods, although the results with beef samples showed considerable variation. Both systems were able to detect low (1–5 cfu/g or /ml) numbers of salmonellas in foods after non‐selective (18 h) and selective (22 h) enrichment steps but four samples, out of 147, gave false positive results. False positive results were eliminated by reducing the enrichment steps to 6 h and 18 h respectively (90 samples).
Incidence of toxigenic vibrios in foods available in Taiwan
Authors: Wong Hin‐Chung , Ting Shu‐Hua , Shieh Wan‐Ru
Published: March 2008

A total of 1088 vibrios and related species were isolated from seafood and aquacultured foods available in Taiwan. They were identified as Vibrio alginolyticus, V. cholerae, V. fluvialis I, V. fluvialis II, V. parahaemolyticus, V. mimicus, Aeromonas caviae, A. hydrophila, A. sobria and other species. Incidence of these Vibrio and Aeromonas species in these foods was high. Vibrio parahaemolyticus was frequently found in seawater and in foods of freshwater origin. The Vibrio isolates were examined for enzymatic and toxigenic activities. Most of them showed strong lipase or protease activities. Haemolytic activities of V. cholerae, V. fluvialis I and V. fluvialis II isolates were mostly strong. About 49% showed cytotoxic activity and 5% cytotonic activity in Chinese hamster ovary cell culture assay. Nevertheless, only three non‐1 V. cholerae (2.07%) and two V. parahaemolyticus isolates (1.65%) produced cholera toxin and thermostable direct haemolysin activity, respectively. Various toxigenic vibrios may be important food‐borne pathogens in this region because of their high incidence in foods.
Laboratory performance in a food microbiology proficiency testing scheme
Authors: Peterz M.
Published: March 2008

Results from two shipments in a proficiency testing scheme in which almost 200 food microbiology laboratories participated are summarized. Freeze‐dried mixtures of bacteria were used as simulated food samples. Four and six samples, respectively, were examined. The statistical procedures used to evaluate the performance of participating laboratories are described. It is shown that laboratories which had been in the scheme for a long time perform, on average, better than those that had been in the scheme for a short time. The former laboratories produced fewer false and outlying results, and were more accurate and precise in their determinations.
Mobilization and expression of bacteriocin plasmids from Carnobacterium piscicola isolated from meat
Authors: Ahn C. , Stiles M.E.
Published: March 2008

Mobilization and expression of bacteriocin plasmids from Carnobacterium piscicola isolated from meat. The nonconjugative plasmids pCP40 and pCP49 associated with bacteriocin production in Carnobacterium piscicola LV17, a lactic acid bacterium isolated from meat, were mobilized by the wide host range conjugative plasmid pAMβ1 by two stage conjugation. At the first stage, pAMβ1 was conjugally transferred into C. piscicola LV17 containing the two plasmids associated with bacteriocin production and a cryptic plasmid. Mobilization of the two bacteriocin plasmids by pAMβ1 was done by the second stage conjugation between the pAMβ1‐containing C. piscicola LV17 and chloramphenicol (Cm)‐resistant Bac‐ mutant of C. piscicola LV17. The transconjugants had either partial bacteriocin activity associated with acquisition of pCP40 or pCP49, or complete bacteriocin activity associated with acquisition of all three of the resident plasmids from C. piscicola LV17 or an 89 MDa cointegrated plasmid derived from pCP40 and pCP49. Further manipulation of the transconjugants and a mutant strain of C. piscicola LV17 resulted in separate strains with only pCP40 or pCP49 which produce different bacteriocins. The bacteriocin gene from pCP49 was cloned into pCaT, a chloramphenicol resistance‐encoding vector, and electrotransformed into another bacteriocin‐producing strain of C. piscicola, enhancing the antagonistic spectrum of the recipient strain.
Influence of the sporulation temperature upon the heat resistance of Bacillus subtilis
Authors: Condon S. , Bayarte M. , Sala F.J.
Published: March 2008

The influence of different sporulation temperatures (30, 37, 44 and 52°C) upon heat resistance of Bacillus subtilis was investigated.

Heat resistance was greater after higher sporulation temperatures. Relation of heat resistance and temperature of sporulation was not linear over all the range of temperatures tested. Heat resistance increased about tenfold in the range of 30–44°C. Sporulation at 52°C did not show any further increase in heat resistance.

This effect was constant over all the range of heating temperatures tested (100–120°C). z value remained constant (z= 9°C).

Greater heat resistances at higher temperatures of sporulation were not due to selection of more heat resistant cells by a higher sporulation temperature. Spores obtained from cells incubated at 32 or 52°C always possessed heat resistances that corresponded to the sporulation temperature regardless of the incubation temperature of their vegetative cells.
Enterotoxin production in different Staphylococcus aureus biotypes isolated from food and meat plants
Authors: Isigidi B.K. , Mathieu A‐M. , Devriese L.A. , Godard C. , Hoof J. Van
Published: March 2008

Strains of Staphylococcus aureus isolated in Belgium and Zaïre from food and from various sources in the meat industry were biotyped, phage typed and tested for staphylococcal enterotoxin (SE) production. Thirty of the 185 strains examined produced one or more SE, and 23 of these belonged to the human biotype. Most SE‐positive strains belonged to phage groups III and Mixed, or were not typable. None of the poultry‐like biotype strains, which were frequent in nasal carriers among workers in meat plants as well as in minced meat, produced enterotoxins. Avian biotype strains similarly were negative.
Causes of conductance change in yeast cultures
Authors: Owens J.D. , Konířová L. , Thomas D.S.
Published: March 2008

The conductance change due to growth of Saccharomyces cerevisiae Y112, Zygosaccharomyces bailii M and Rhodotorula rabra NCYC 63 in culture media containing glucose, tartrate pH buffer and ammonium ions as sole nitrogen source was compared with that in a medium containing L‐asparagine as sole nitrogen source. Decreases in conductance were observed in glucose‐ammonium cultures of all three yeasts while little change occurred in cultures with L‐asparagine as sole nitrogen source. This supports the hypothesis that the metabolic activity primarily responsible for conductance change in yeast cultures is the uptake of charged ammonium ions as nitrogen source and the reaction of protons with pH buffer compounds.

Rhodotorula rubra cultures with L‐asparagine as sole carbon source caused large increases in conductance with growth. Chemical analyses of culture filtrates showed that this increase in conductance was due to use of L‐asparagine as carbon source and the excretion of nitrogen surplus to biosynthetic needs as ammonium. In addition, the production of aspartate, acetate and bicarbonate contributed to the increase in conductance.
Properties of ionophore‐resistant Bacteroides rurninicola enriched by cultivation in the presence of tetronasin
Authors: Newbold C.J. , Wallace R.J. , Watt Nicola D.
Published: March 2008

Bacteroides ruminicola M384 was grown in the presence of increasing concentrations of tetronasin, an ionophore that has been developed as a feed additive for ruminants. The resulting culture, B. ruminicola M384/TnR, was then maintained in medium containing 0.1 pg tetronasin/ml. Growth of the parent strain was eliminated by the addition of 0.1 ug tetronasin/ml, but the growth rate of B. ruminicola M384/TnR, which grew more slowly than the parent strain, was unaffected by adding tetronasin. Bacteroides ruminicola M384/TnR retained its resistance to tetronasin even after repeated subculture in the absence of the ionophore, suggesting that a mutation had occurred. The absence of plasmids in individual colonies of B. ruminicola M384/TnR implied that the mutation was chromosomal. Bacteroides ruminicola M384/TnR was also more resistant to the ionophores monensin and lasalocid and, to a lesser degree, to the antibiotic avoparcin than B. ruminicola M384. Binding of [14C]tetronasin to B. ruminicola M384/TnR was lower than binding of the ionophore to the parent stain, and this difference was eliminated by washing cells with EDTA. The peptidolytic activity of B. ruminicola M384 towards triphenylalanine (Mr= 460) was unaffected in B. ruminicola M384/TnR, but the rate of breakdown of tetra‐phenylalanine (Mr= 607) was decreased. This difference was also abolished by EDTA. It was concluded that growth of B. ruminicola in the presence of tetronasin resulted in a mutation affecting the permeability of the cell envelope, such that permeation of tetronasin and molecules of a similar size (Mr= 628) was decreased.
Efficacy of copper and silver ions with iodine in the inactivation of Pseudomonas cepacia
Authors: Pyle B.H. , Broadaway S.C. , McFeters G.A.
Published: March 2008

Alternatives to chlorination of water have been sought for reasons which include trihalomethane formation, possible bacterial regrowth, the high concentrations of chlorine required in certain circumstances, and the taste, odour and bodily irritation in chlorine‐treated water. Electrolytically generated Cu and Ag ions at low levels, in addition to very low chlorine concentrations, have been suggested as an alternative to routine chlorination. We have examined the combination of Cu and Ag ions with low levels of iodine. Pseudomonas cepacia was grown either in rich medium or under nutrient restriction prior to disinfection. Survival of the organism and its ability to regrow after treatment as well as the effects of varying buffers, metal ion and iodine concentrations were determined. Low concentrations of metal ions (100 ppb Cu and 11 ppb Ag) and iodine (200 ppb) were more effective than either metal ions or iodine alone against Ps. cepacia grown on rich agar or in low nutrient buffer. After iodination, buffer‐grown suspensions recovered to their original cell concentrations within 7 d. When Cu and Ag ions were used with or without iodine, regrowth was prevented. The results show that low concentrations of Cu and Ag in combination with iodine permit effective disinfection of bacteria after cultivation on either rich media or under nutrient restriction. These results, along with published data, suggest that the combination of these metals with halogenation may have applications in the disinfection of both recreational and potable water.
Fast atom bombardment‐mass spectrometry for bacterial chemotaxonomy: influence of culture age, growth temperature, gaseous environment and extraction technique
Authors: Aluyi H.S. , Boote Valerie , Drucker D.B. , Wilson J.M.
Published: March 2008

Extracted phospholipids of Escherichia coli, Proteus mirabilis and Enterobacter cloacae were examined by fast atom bombardment‐mass spectrometry which yielded major peaks between m/z 225 and 761. The result of extracting freeze‐dried or ‘wet’ cells showed that freeze‐drying may be omitted although weighing of dried cells offers a useful means of standardizing the extraction procedure. Anaerobic growth quantitatively altered the chemical finger‐print as a result of increase in ratio of saturated: unsaturated carboxylic acids. Growth temperature also affected profiles over the temperature range 24–45°C. A less drastic influence on mass spectra was culture age, over the range 16–48 h. Comparison of spectra was possible with Pearson's coefficient of linear correlation which yielded the following values: wet and lyophilized cells, r= 0–97; aerobic and anaerobic growth, r= 0.82; 24°C and 45°C, Y = 0.76; 16 h and 48 h, r= 0.95. These results show that although quantitative differences do occur between spectra for the same organism prepared in different ways, they are less than interspecies variation, e.g. with E. coli and P. mirabilis, r= 0.46. Any differences which are due to preparation method can be overcome by standardization of technique.