bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of quantal response data from bacterial destruction studies in sterilization: the Stumbo estimate is biased
Authors: Hachigian J. , Schlesinger R.J.
Published: March 2008

J. HACHIGIAN AND R.J. SCHLESINGER. 1991. Real and simulated experimental data and theoretical data from quantal response experiments were used to make a comparison between the analysis of data from a quantal response experiment and data from a direct enumeration experiment. The method of analysis for each is differentiated, thereby enhancing the utility of the quantal response experiment in sterilization studies. From this comparison it appears that the Stumbo estimate of the D value is biased. Furthermore, the Stumbo estimate depends upon the spore load per replicate in quantal response type experiments, which makes experimental comparisons difficult. Another estimate of D is demonstrated which overcomes some of these shortcomings.
Streptococcal ecovars associated with different animal species: epidemiological significance of serogroups and biotypes
Authors: Devriese L.A.
Published: March 2008

Traditionally the classification and identification of streptococci from clinical and veterinary sources have been based on the serogrouping of the carbohydrate antigens of the cell walls by the method of Lancefield (1933). This classification, devised for beta‐haemolytic streptococci, was unable to accommodate all streptococci because many alpha and non‐haemolytic strains do not possess the groupspecific antigen.
Use of the polymerase chain reaction for direct detection of Listeria monocytogenes in soft cheese
Authors: Wernars K. , Heuvelman C.J. , Chakraborty T. , Notermans S.H.W.
Published: March 2008

The polymerase chain reaction (PCR) amplification technique was investigated as a tool for direct detection of Listeria monocytogenes in soft cheeses. Different sets of oligonucleotide primers were used, and parts of the L. monocytogenes Dth18‐gene could be amplified specifically when either a plasmid vector carrying the cloned gene or chromosomal DNA was used as a template. The detection limit for L. monocytogenes in dilutions of pure cultures was between 1 and 10 colony‐forming units. In extracts from soft cheeses containing L. monocytogenes DNA, the amplification was strongly inhibited. This inhibition could be reduced by an additional purification step. Despite this the detection limit showed a large variation, depending on the brand of cheese used. In some cheeses 103 cfu/0.5 g could be visualized whereas in others the presence of 108 cfu/0.5 g did not yield a detectable quantity of amplified product.
Antibiosis of Leuconostoc gelidum isolated from meat
Authors: Hastings J.W. , Stiles M.E.
Published: March 2008

A heterofermentative lactic acid bacterium isolated from meat packaged under elevated CO2 levels was identified as Leuconostoc gelidum, based on the description of this new species by Shaw & Harding (1989). It grows well at refrigeration temperatures but not at 35°C. The organism produces an inhibitory substance that is inactivated by protease and trypsin, but not by catalase or by heating at 62°C for 30 min. The bacteriocin‐like inhibitory substance is produced early in the growth cycle, at 1, 5 and 25°C. The inhibitory substance is active against a large number of closely related lactic acid bacteria, as well as a strain of Enterococcus faecalis and Listeria monocytogenes. There is initial evidence that the genetic information determining production of, and resistance to, the bacteriocin‐like substance is plasmid mediated. Of the three plasmids found in this organism, loss of the 7.6 MDa plasmid resulted in loss of inhibitor production and resistance to the inhibitory substance. Loss of the 5.0 MDa plasmid did not result in a detectable phenotypic change in the organism.
Inhibition of Escherichia coli K12 by short‐chain organic acids: lack of evidence for induction of the SOS response
Authors: Cherrington Christina A. , Hinton M. , Pearson G.R. , Chopra I.
Published: March 2008

Sublethal concentrations of formic acid (10 mmol/l) and propionic acid (5 mmol/l) at pH 5.0 preferentially inhibit DNA synthesis and stop cell multiplication in the absence of a corresponding cessation in the increase of culture turbidity. The possibility that the acids induce the SOS response by starving cells of thymine or by causing physical damage to the DNA molecule has now been investigated. Accumulation of thymine into the cytoplasm of whole cells was not inhibited by either acid. Mutants defective in excision repair (uvrA6), recombination repair (recA56) and polymerase activity (polA1) were not more sensitive to the acids than their isogenic parent. No significant increase in cell length was observed from measurements of transmission electron microscope images of acid‐treated cells. It is concluded, therefore, that sublethal concentrations of formic and propionic acid inhibit DNA synthesis without physically damaging DNA molecule, or starving the cell of essential thymine or otherwise inducing an SOS response.
The effect of veratrole on carotenoid biosynthesis by Phycomyces blakesleeanus
Authors: Shlomai P. , Ben‐Amotz A. , Margalith P.
Published: March 2008

A number of chemical compounds are known to affect the biosynthetic pathways of β‐carotene. Both site‐specific inhibitors as well as general stimulators of carotenogenesis have been described. It has been reported that veratrole enhances β‐carotene synthesis when applied to agar cultures of Phycomyces blakesleeanus but we found no significant stimulation of β‐carotene production in submerged culture. Moreover, veratrole in high concentrations (> 0.1% w/v), unlike diphenylamine, inhibits the formation of phytoene, resulting in an almost total block of carotenoid biosynthesis.
Degradation of lignin and lignin derivatives by Acinetobacter sp.
Authors: Vasudevan N. , Mahadevan A.
Published: March 2008

An Acinetobacter sp. utilized 2‐methoxy‐4‐formylphenoxyacetic acid, dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin as sole carbon source. It also degraded 14C‐labelled DHP lignin and teakwood lignin. Vanillic acid, protocatechuic acid and catechol were separated from 2‐methoxy‐4‐formylphenoxyacetic acid grown cultures. Both protocatechuic acid and catechol were formed from dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin. On the dimeric lignin model substances this Acinetobacter sp. produced protocatechuate 3,4‐dioxygenase and catechol 1,2‐dioxygenase.
Detection and prevalence of Listeria monocytogenes in the agricultural ecosystem
Authors: Renterghem B. Van , Huysman F. , Rygole R. , Verstraete W.
Published: March 2008

B. VAN RENTERGHEM, F. HUYSMAN, R. RYGOLE AND W. VERSTRAETE. 1991. The sensitivity of four different enrichment procedures to detect Listeria monocytogenes in the presence of high levels of Streptococcus faecalis was investigated. Defined mixed cultures of Strep. faecalis and L. monocytogenes gave better results with one‐stage enrichment techniques. For manure samples, however, two‐stage enrichment techniques gave the best performance. The so‐called cold enrichment techniques were found to be unsatisfactory for samples from natural environments. The following materials were examined for the presence of L. monocytogenes: fresh pig faeces (16% positive), fresh cattle faeces (20% positive), stored liquid manure (0% positive), manured soil samples (0% positive) and ground water samples (5% positive). After 3 weeks of storage L. monocytogenes could be detected in only one of the initially nine positive fresh facces samples. Two months after inoculation of stored liquid pig manure, stored liquid cattle manure and soil with L. monocytogenes, this bacterium could not be traced in any of these materials. Radishes (Raphanus sativus) and carrots (Daucus carota), sown in soil inoculated with L. monocytogenes, were gathered after 3 months and examined for the presence of L. monocytogenes. Three of six radish samples were found to be positive. Remarkably, however, all carrot samples (six) were free of L. monocytogenes.
Screening of strains identified as extremely thermophilic bacilli for extracellular proteolytic activity and general properties of the proteinases from two of the strains
Authors: Coolbear T. , Eames C.W. , Casey Y. , Daniel R.M. , Morgan H.W.
Published: March 2008

T. COOLBEAR, C.W. EAMES, Y. CASEY, R.M. DANIEL AND H.W. MORGAN. 1991. Forty‐one strains isolated from thermal areas in New Zealand, Fiji and Antarctica were shown to be extremely thermophilic Bacillus spp. (growth optima > 65.C) by comparison with reference strains with a series of standard tests. Some morphological and physiological variation between strains was noted. Various assay procedures were employed to assess the strains for their ability to produce extracellular proteolytic activity. The strain EA. 1 gave the highest yield of proteolytic activity under the conditions imposed. A second strain, OK3A.1, also gave high yields of activity but differed from the EA.1 activity in that it was more tolerant to both high pH and EDTA. The proteinases from these two strains were purified and characterized. Maximum activity was given by EA.1 proteinase over a narrow pH range with an optimum at pH 6.7 and 50% activity limits at pH 5.6 and 7.5. OK3A.1 had a similar pH optimum but was active over a broader range with 50% activity limits at pH 5.2 and 8.5. Both enzymes were endo‐acting proteinases; neither showed activity against two small synthetic peptides. By SDS‐polyacrylamide gel electrophoresis the molecular masses for EA.1 proteinase and OK3A.1 proteinase were 42 000 Da and 32 000 Da respectively. Both enzymes were resistant to 10 mmol/1 phenylmethylsulphonylfluoride and iodoacetic acid, but were deactivated by EDTA. Whereas EA.1 proteinase was inhibited by o‐phenanthroline and activated by zinc ions, OK3A.1 proteinase was unaffected by either agent although some dependence on divalent metal ions for activity was apparent. The enzymes were stabilized by calcium ions, EA.1 proteinase exhibiting a half‐life of 2 h at 85.C whilst OK3A.1 proteinase was less stable with a half‐life of 40 min at this temperature.
The adsorption of bacteria to immobilized lectins
Authors: Patchett R.A. , Kelly Alison F. , Kroll R.G.
Published: March 2008

R.A. PATCHETT, A.F. KELLY AND R.G. KROLL. 1991. The agglutination of a selection of bacteria by some lectins was examined. The lectin from Codium fragile agglutinated seven strains of Salmonella typhimurium. The lectin from Helix pomatia agglutinated eight of 12 strains of Listeria monocytogenes and a further two strains gave a weak agglutination reaction. Helix pomatia lectin conjugated to magnetic microspheres enabled the adsorption of L. monocytogenes from suspension with subsequent elution by the competing ligand N‐acetyl galactosamine. Affinity chromatography of a suspension of L. monocytogenes through a column of H. pomatia lectin immobilized on agarose, also adsorbed cells and enabled subsequent elution with N‐acetyl galactosamine. The column technique enabled the more rapid adsorption of bacteria perhaps because of improved interactions between bacteria and immobilized lectin.
Effect of simultaneous application of heat and pressure on the survival of bacterial spores
Authors: Mallidis C.G. , Drizou D.
Published: March 2008

C.G. MALLIDIS AND D. DRIZOU. 1991. The effect of simultaneous application of moderate hydrostatic pressure (10–300 atm) and heat on the survival of the Bacillus stearothermophilus spores in a flow‐through system was investigated. A high heterogeneity of the sensitization of spores to heat by pressure was found. A higher degree of reduction of heat resistance was observed at the low than at the high temperatures tested. The simultaneous application of moderate pressure and heat can not be applied for the preservation of liquid foods due to the extreme heterogeneity of spore sensitization to heat by pressure.
Sixty years of the Society for Applied Bacteriology: a story of growth, enterprise and consolidation
Authors: Hopton J.W.
Published: March 2008

The origins and early years of the Society are outlined. The subsequent boom in membership numbers, the development of the programme and the range and volume of the Society's publications are described. The account indicates that the Society has stabilized in size over the last decade but its enthusiasm to honour its constitution has been sustained and its activities have widened. Special interest groups have been created and the scope of meetings has continued to expand. Co‐operation with other bodies, at national and international level, for the organization of colloquia, symposia and conferences, has increased. Young scientists have been encouraged and rewarded. Programmes to foster an awareness of the nature and scope of applied microbiology in schoolchildren have been given financial and practical support. The loyal service of individuals and groups to the administration and organization of the Society is acknowledged.
Unusual methanogenic flora of a wood‐fermenting anaerobic bioreactor
Authors: Macario A.J.L. , Peck M.W. , de Macario Everly Conway , Chynoweth D.P.
Published: March 2008

Antibody probes and immunotechnology were used in qualitative and quantitative studies of the methanogenic flora of two mesophilic continuously stirred tank reactors in which wood or sorghum served as substrates. This represents the first immunological study of a wood‐fermenting bioreactor. An overwhelmingly predominant methanogenic subpopulation was observed which, after 2.5 years of operation represented nearly 90% of all methanogens detectable immunologically, reaching 97% 1 year later. This subpopulation was weakly related antigenically to Methanomicrobium mobile BP and morphologically was indistinguishable from it. Such predominance of a single methanogen subpopulation and its relatedness to M. mobile BP has not been observed previously in bioreactors, and may be a distinctive trait of wood‐fermenting bioreactors. The majority of other methanogens detected immunologically were not of the same immunotype as reference strains, suggesting that important methanogens remain to be isolated from these systems.
Naturally occurring Bacillus thuringiensis in Indonesia
Authors: Hastowo S. , Lay B.W. , Ohba M.
Published: March 2008

S. HASTOWO, B.W. LAY AND M. OHBA. 1992. A total of 135 strains of Bacillus thuringiensis were isolated from soils of sericultural and natural environments of various regions in Indonesia: Sumatra, Java, Bali, Timor, Sulawesi and Kalimantan. Serologically, 63 strains were assigned to flagella (H) serotypes 3abc, 3ade, 4ac, 5ac, 6ab, 8ab, 9, 11, 17, 20ac, and 24, indicating a varied flora of B. thuringiensis in Indonesia. Of these, the serotype 3ade predominated, followed by the serotypes 3abc and 6ab. The other 72 strains (53·3%) were not sero‐reactive against any of the H antisera to B. thuringiensis H serotypes 1–24. In toxicity tests, 34 strains belonging to serotypes 3abc, 3ade, 4ac, and 8ab showed larvicidal activity to the silkworm, Bombyx mori, while 74·8% did not exhibit insecticidal activity against larvae of B. mori and the mosquitoes, Aedes aegypti and Culex quinquefasciatus. Morphotypes of parasporal inclusions were not correlated with insecticidal activities.
The distribution of homologous enterococcal plasmid DNA sequences in human faecal isolates
Authors: Watanabe T. , Kumata H. , Sasamoto M. , Shimizu‐Kadota M.
Published: March 2008

T. WATANABE, H. KUMATA, M. SASAMOTO AND M. SHIMIZU‐KADOTA. 1992. Hybridization was used to investigate the distribution of enterococcal plasmid sequences among 306 strains of Enterococcus and Streptococcus spp. isolated from faeces of humans of various ages. As DNA probes for the survey three plasmids, whose DNAs did not hybridize each other and designated as pMS13, pTW34 and pHK30, were selected from plasmids borne in Ent. faecalis. pTW34 DNA hybridized only with DNAs from enterococci, with high frequency in Ent. faecalis and low frequency in Ent. faecium. pMS13 DNA hybridized with DNAs of all Enterococcus spp. tested and with Strep. bovis, Strep. equinus and Strep. salivarius. Eighty‐five percent of Ent. faecium isolates had sequences homologous to pMS13 but in the other species the values were less than 60%. Some enterococci had DNAs which hybridized with the pHK30 probe. The different distribution of the three DNA sequences indicates the possibility that plasmid DNAs encode advantageous phenotypes for the colonization of bacteria in the lumen of the bowel.
Intergeneric conjugation in Thiobacillus versutus
Authors: Read Dorothy L. , Toth L. M. , McCann K.
Published: March 2008

D.L. READ, L.M. TOTH AND K. McCANN. 1992. In plate matings with Escherichia coli HB101/pUW965: Tn5 (KmR) Thiobacillus versutus reacted as an efficient recipient, producing 10‐2 to 10‐3 kanamycin resistant (KmR) T. versutus exconjugants per donor cell. Analysis of agarose gels of plasmid DNA extracted from the exconjugants confirmed that the suicide vector pUW964 did not persist in the recipient, implying that the kanamycin resistance of the exconjugants is based on effective transposition of Tn5 in T. versutus as well as function of the E. coli kanamycin gene. Transfer was equally efficient when a nalidixate‐resistant T. versutus mutant was used as recipient. Hybridization evidence for the presence of Tn5 was consistently negative. The significance of this anomalous result is discussed.
Isolation of inclusion bodies from vegetative Clostridium perfringens: partial purification of a 47 kDa inclusion protein
Authors: Garcia‐Alvarado J.S. , Labbé R.G. , Rodriguez M.A.
Published: March 2008

J.S. GARCIA‐ALVARADO, R.G. LABBÉ AND M.A. RODRIGUEZ. 1992. A refractile inclusion body produced by vegetative cells of Clostridium perfringens at temperatures above 40d̀C was isolated and partially characterized. The inclusion was composed of protein and could be solubilized by sodium dodecyl sulphate plus either dithiothreitol or β‐mercaptoethanol. The solubilized inclusion showed no antigenic relationship with Cl. perfringens enterotoxin. One major band with an apparent MW of 47 kDa was demonstrated after polyacrylamide gel electrophoresis of the solubilized inclusion. Both enterotoxin‐positive and enterotoxin‐negative strains produced the inclusion body. No effect on the morphology of several eucaryotic cell lines was observed when solubilized or intact inclusion was added to the cell cultures.
Evaluation of four membrane filter media in anaerobic‐MF recovery of faecal coliforms from freshwater in Nigeria
Authors: Ogan M.T.
Published: March 2008

M.T. OGAN. 1992. MacConkey (MC), membrane lauryl sulphate (MIS), membrane faecal coliform amended with rosolic acid (MFC + R) and without the acid (MFC — R) were evaluated in the anaerobic membrane filtration (anaerobic‐MF) recovery of faecal coliform populations (FCs), genera and faecal coliform positive (FC‐positive) strains isolated from various sources of freshwater, i.e. rivers, rural wells, unchlorinated distributive supplies and hand pumps. Mean counts (x 102/100 ml) of presumptive (typical) FCs varied from 13.69 (MC) to 40.81 (MLS) in river samples, and from 2.0 (MC) to 4.19 (MFC + R) in wells. The proportion of FC‐positive, typical FCs ranged from 48.66 (MIS) to 66.67% (MC) in rivers, and from 50 (MC) to 90.22% (MFC + R) in wells. More than 30% of the typical FCs from all sources on each medium was FC‐negative. These usually formed small (ca 1.0 mm diam.) colonies on the test agar, and were prevalent in wells. Typical FCs and FC‐positive strains were not recovered from piped supplies and hand pumps. In spite of anaerobic incubation, non‐faecal coliforms (NFCs) were often higher than the FCs; the FC: NFC ratios for rivers ranged from 1.65 (MC) to 7.65 (MLS) and (MFC + R) but were < 1.0 for wells on each medium. Escherichia coli, Klebsiella and Enterobacter species were recovered on all media: approximately 35–64% of the strains confirmed as FCs were E. coli, 20–42% were Kl. pneumoniae. The FC counts on the media were variable, but the overall performance in recovering ‘true’ FCs was similar; < 70% of strains per medium were FC‐positive. None could count E. coli exclusively.
The relationships between salmonellas and faecal indicator concentrations in two pools in the Australian wet/dry tropics
Authors: Townsend S.A.
Published: March 2008

S.A. TOWNSEND. 1992. The relationships between total coliform, faecal coliform, enterococci and salmonella concentrations were investigated at Berry and Howard Pools in the Australian wet/dry tropics. Both pools have catchments with minimal human activity and no major point source of faecal pollution. Forty‐five indicator and salmonella enumerations were made from each pool over a 1 year period. Salmonellas were isolated from 69% and 96% of samples collected from Howard and Berry Pools respectively, the maximum (MPN) concentration was 110/100 ml. Native fauna were the primary salmonella source. Spearman rank correlations between indicator organisms and salmonella at Howard Pool were significant at the 5% level and approximated 0.6. At Berry Pool, total coliform and enterococci Spearman rank correlations with salmonella were also statistically significant, approximating 0.3; faecal coliforms and salmonella rankings, however, were unrelated. The higher correlation coefficients at Howard Pool were attributed to its small catchment (4 km2) and the more recent nature of faecal contamination compared with Berry Pool which has a catchment of 130 km2. The results highlight the spatial variability of the indicator/pathogen numerical relationship. Total coliform and enterococci counts, as indicators of faecal pollution, were similar and more consistent than faecal coliforms.
The development and use of monoclonal antibodies for detection of Erwinia
Authors: Vernon‐Shirley M. , Burns R.
Published: March 2008

M. VERNON‐SHIRLEY AND R. BURNS. 1992. Three monoclonal antibodies (McAb), which reacted specifically with Erwinia carotovora, were produced. Monoclonal antibody 14/8.6 reacted with serogroup I/3390 but not with two other serogroups of E.c. subsp. atroseptica nor with 31 serogroups of E.c. subsp. carotovora; McAb 14/2 reacted with all 34 serogroups; and McAb 14/8.6 was as sensitive as a commercially produced polyclonal antiserum in detecting E.c. subsp. atroseptica by enzyme‐linked immunosorbent assay.
Isolation of salmonellas by immunomagnetic separation
Authors: Vermunt A.E.M. , Franken A.A.J.M. , Beumer R.R.
Published: March 2008

A.E.M. VERMUNT, A.A.J.M. FRANKEN AND R.R. BEUMER. 1992. Magnetisable particles, coated with anti‐salmonella serum, were used to isolate Salmonella livingstone from pure cultures, mixed cultures and food samples. Beads (107) were generally incubated with 104Salm. livingstone cells/ml for 60 min at room temperature. The incubation and washing medium (0.01 mol/l phosphate‐buffered saline; PBS) contained 0.1% bovine serum albumin (BSA) and 0.1% Tween 20, respectively. This method gave a recovery for Salm. livingstone of 51.9±7.8%. However, other micro‐organisms such as Aeromonas hydrophila interfered with this test because of non‐specific reactions (recovery 50.9±12.7%). These non‐specific reactions could be decreased by using 4% skim milk instead of 0.1% BSA in the incubation medium. The ratio of the recovery of Salim. livingstone relative to the recovery of Aer. hydrophila changed from 0.9 when PBS with 0.1% BSA was used, to 13.4 when PBS with 4% skim milk was used. Immunomagnetic separation of Salmonella spp. from food samples offers good prospects for concentrating salmonella cells from heterogeneous bacterial suspensions, such as enrichment broths.
Sandwich capture ELISA by a murine monoclonal antibody against a genus‐specific LPS epitope for the detection of different common serotypes of salmonellas
Authors: Choi Debby , Tsang R.S.W. , Ng M.H.
Published: March 2008

D.CHOI, R.S.W. TSANG AND M.H. NG. 1992. A sandwich capture ELISA based on a murine monoclonal antibody against a genus‐specific epitope in the outer core region of the Salmonella lipopolysaccharide is described for the detection of different common serotypes of salmonellas. Four h broth cultures of seven standard and 24 wild strains of salmonellas were all detected by the capture ELISA while overnight broth cultures of 21 non‐salmonella standard strains were all negative. The capture ELISA detected 1 ng/ml of Ra lipopolysaccharide, 106/ml of a smooth wild strain of Salm. typhimurium, and 1120 cells of Salm. heidelberg after enrichment culture for 4 h.
Interaction of Bacillus subtilis spores with sodium hypochlorite, sodium dichloroisocyanurate and chloramine‐T
Authors: Bloomfield Sally F. , Arthur M.
Published: March 2008

S.F. BLOOMFIELD AND M. ARTHUR. 1992. Solutions of chlorine‐releasing agents (CRAs) show varying activity against Bacillus subtilis spores; sodium hypochlorite (NaOCl) shows higher activity than sodium dichloroisocyanurate (NaDCC) which is more active than chloramine‐T. Investigations with coat‐ and cortex‐extracted spores indicate that resistance to CRAs depends not only on the spore coat but also the cortex. Whereas extraction of alkali‐soluble coat protein increased sensitivity to NaOCl and NaDCC, degradation of coat and cortex material was required to achieve significant activity with chloramine‐T. NaOCl (in the presence and absence of NaOH) and NaDCC (in the presence of NaOH only) produced degradation of spore coat and cortes material which may be related to their rapid sporicidal action at low concentrations under these conditions. By contrast, chloramine‐T produced no degradation of cortex peptidoglycan and was only effective against normal and alkali‐treated spores at high concentrations, requiring extraction of peptidoglycan with urea/dithiothreitol/sodium lauryl sulphate (UDS) or UDS/lysozyme to achieve significant activity at low concentrations. Results suggest that the sporicidal action of CRAs is associated with spore coat and cortex degradation causing rehydration of the protoplast allowing diffusion to the site of action on the underlying protoplast.
Nikkomycin production in pellets of Streptomyces tendae
Authors: Vecht‐Lifshitz S.E. , Sasson Y. , Braun S.
Published: March 2008

S.E. VECHT‐LIFSHITZ, Y. SASSON AND S. BRAUN. 1992. In previous submerged fermentation experiments mycelial suspensions of Streptomyces tendae were viscous and availability of oxygen limited the yield of nikkomycins (Nk), a complex of secondary metabolites which includes nucleoside‐peptides with antibiotic activity. Increasing agitation improved oxygen transfer but consumed considerable power and shear‐damaged cells. In this paper, cellular aggregates (pellets) were used to reduce viscosity and protect cells from shear. Under the conditions tested, specific productivity of S. tendae pellets increased with increasing size up to 1.4 mm diameter and then decreased. The maximal specific productivity of S. tendae pellets (44 mg Nk/g dry weight/h) occurred at a very low cell concentration. Pellet formation or high biomass concentration was required for the production of bioactive dipeptide and tripeptide Nks. It is speculated that accumulation of intermediates in large pellets activates the production of mature secondary metabolites.
Prevalence of coaggregation reactions among chicken lactobacilli
Authors: Vandevoorde L. , Christiaens H. , Verstraete W.
Published: March 2008

L. VANDEVOORDE, H. CHRISTIAENS AND W. VERSTRAETE. 1992. Interbacterial adherence was frequently encountered among chicken lactobacilli. Fourteen of 45 combinations involving nine adhering strains were shown to be coaggregative. The coadherence mechanism was mediated by complementary heat‐ and sonication‐sensitive cell surface structures. It was shown that intrageneric adherence enabled lactobacilli to maintain higher numbers in fed‐batch reactors simulating the gastrointestinal tract. The mechanism of coaggregation can substantially increase the colonization potential of lactobacilli in environments with short residence times.
Pseudomonas fluorescens subsp. cellulosa: an alternative model for bacterial cellulase
Authors: Hazlewood G.P. , Laurie J.I. , Ferreira L.M.A. , Gilbert H.J.
Published: March 2008

G.P. HAZLEWOOD, J.I. LAURIE, L.M.A. FERREIRA AND H.J. GILBERT. 1992. Pseudomonas fluorescens subsp. cellulosa, a Gram‐negative soil bacterium, can utilize crystalline cellulose or xylan as main sources of carbon and energy. Synthesis of endoglucanases and xylanases is induced by Avicel, filter paper, carboxymethylcellulose or xylan and is repressed by cellobiose, glucose or xylose. These enzymes are secreted into the culture supernatant fluid and do not form aggregates or associate with the cell surface. Cells of Ps. fluorescens subsp. cellulosa do not adhere to cellulose. In cultures containing Avicel or filter paper, a significant proportion of the secreted cellulase and xylanase activities becomes tightly bound to the insoluble cellulose. Western blotting has revealed that endoglucanase B, xylanase A and a cellodextrinase encoded by genes previously isolated from Ps. fluorescens subsp. cellulosa and expressed in Escherichia coli, are synthesized by the pseudomonad under a variety of conditions. These enzymes appear to be post‐translationally modified, probably through glycosylation. Overall, it appears that the cellulase/hemicellulase system of Ps. fluorescens subsp. cellulosa differs from the model established for celluloytic anaerobes such as Clostridium thermocellum.
Multiple typing techniques applied to a Clostridium perfringens food poisoning outbreak
Authors: Mahony D.E. , Ahmed R. , Jackson S.G.
Published: March 2008

D.E. MAHONY, R. AHMED AND S.G. JACKSON, 1992. Twenty‐one stool specimens obtained from persons implicated in two food poisoning outbreaks at the same institution in Smith Falls, Ontario, were examined for Clostridium perfringens. Ninety‐two colonies of Cl. perfringens (3–5 per stool specimen) were typed with antisera, bacteriocins and by plasmid analysis. They were also tested for the in vitro production of bacteriocin and enterotoxin. Sixteen of the 21 stool specimens were tested directly for enterotoxin. This was detected in 13, five of which were from individuals listed as ‘asymptomatic’ food handlers. The predominant strain isolated from 15 of the 21 stool samples produced bacteriocin and enterotoxin in vitro, contained no plasmids, and was of a common bacteriocin type and serotype.
Effect of culture age, pre‐incubation at low temperature and pH on the thermal resistance of Aeromonas hydrophila
Authors: Condón S. , García María L. , Otero A. , Sala F.J.
Published: March 2008

S. CONDON, M.L. GARCIA, A. OTERO AND F.J. SALA. 1992. The thermal resistance of Aeromonas hydrophila strain NCTC 8049 was determined within the range 48°‐65°C with a thermoresistometer TR‐SC and McIlvaine buffer. The effects of culture age, pre‐incubation at 7°C and the pH of the heating menstruum were evaluated. The pattern of thermal death was dependent on culture age. Cells heated in the late logarithmic growth phase (15 h at 30°C) were twice as resistant as those in the early stage (5 h at 30°C), and the maximum D‐value was obtained after 72 h incubation (5.5 total increase). The age of the cells did not affect z‐values significantly. The heat resistance of cells incubated for 48 h at 30°C increased (twice) after holding at 7°C for 72 h. Pre‐incubation at low temperature of older cultures (72 h, 30°C) did not influence their D‐values. Maximum heat resistance was found at pH 6.0 and minimal at pH 4.0. Decreasing the pH from 6.0 4.0 reduced D‐values by a factor of 5. Although the strain studied was heat‐sensitive (D55°C= 0.17 min; z= 5.11°C), survivor curves of cultures older than 50 h showed a significant tailing. Organisms surviving in the tails were only slightly more resistant than were the original population.
Factors affecting antibacterial activity of hop compounds and their derivatives
Authors: Simpson W.J. , Smith A.R.W.
Published: March 2008

W.J. SIMPSON AND A.R.W. SMITH. 1992. The antibacterial effect of weak acids derived from the hop plant (Humulus lupulus L.) increased with decreasing pH. Analysis of the minimum inhibitory concentration of such compounds against Lactobacillus brevis IFO 3960 over pH4–7 suggests that undissociated molecules were mainly responsible for inhibition of bacterial growth. The antibacterial activity of trans‐isohumulone was ca 20 times greater than that of humulone, 11 times greater than that of colupulone and nine times greater than that of trans‐humulinic acid when the degree of ionization was taken into account. Monovalent cations (K+, Na+, NH4+, Rb+, Li+) stimulated antibacterial activity of trans‐isohumulone but the effect was smaller than that observed with H+. The response to divalent cations varied: Ca2+ had little effect on antibacterial activity, whereas Mg2+ reduced activit. Lipid materials and β‐cyclodextrin also antagonized the antibacterial action of trans‐isohumulone.
Typing of Aeromonas strains from patients with diarrhoea and from drinking water
Authors: Havelaar A.H. , Schets F.M. , van Silfhout A. , Jansen W.H. , Wieten G. , van der Kooij D.
Published: March 2008

A.H. HAVELAAR, F.M. SCHETS, A. VAN SILFHOUT, W.H. JANSEN, G. WIETEN & D. VANDER KOOIJ. 1992. Aeromonas strains (187) from human diarrhoeal stools and from drinking water (263) in The Netherlands were typed by three different methods. Biotyping alone was found to be of little value for epidemiological studies because 84% of all strains belonged to only 10 biotypes. Common biotypes could be further differentiated by serotyping. Gas‐liquid chromatography of cell wall fatty acid methyl esters (FAME) was useful for species identification as well as for typing: 86% of all strains could be identified to the species level, and within this group 92% of all identifications corresponded with the biotype. Cluster analysis and principal component analysis of FAME profiles could be used for comparison of strains from different sources and gave the same general conclusions as bio‐ and serotyping. There was little overall similarity between Aeromonas strains from human (diarrhoeal) faeces and from drinking water, differences being most pronounced for Aeromonas caviae and least for A. sobria.
Hydrolysis of vicine and convicine from fababeans by microbial β‐glucosidase enzymes
Authors: McKay A.M.
Published: March 2008

A.M. MCKAY. 1992. The toxic glycosides vicine and convicine which are present in fababeans have been implicated in favism, an anaemic disease of humans. Vicine and convicine concentrations are reduced by growth of Lactobacillus plantarum on fababean suspensions. The glycosides are eliminated from the fababean substrate by the growth of the filamentous fungus Fusarium graminearum. Incubation of fababean suspension with concentrated culture filtrate of Aspergillus oryzae, induced for extracellular β‐glucosidase production, results in complete degradation of the glycosides. This study suggests a potential use of micro‐organisms or microbial enzymes for detoxification of fababeans.
Detection of enterotoxins and TSST‐1 secreted by Staphylococcus aureus isolated from ruminant mastitis. Comparison of ELISA and immunoblot
Authors: Orden J.A. , Goyache J. , Hernández J. , Doménech A. , Suárez G. , Gómez‐Lucia E.
Published: March 2008

J.A. ORDEN, J. GOYACHE, J. HERNÁNDEZ, A. DOMÉNECH, G. SUÁREZ AND E. GÓMEZ‐LUCÍA. 1992. The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin‐1 (TSST‐1) was studied in 81 strains of Staphylococcus aureus isolated from cases of mastitis in cattle, goats and sheep. SE and TSST‐1 were detected by two techniques: ELISA double antibody sandwich, and an immunoblot technique combined with a semiautomated electrophoresis system. More Staph. aureus strains isolated from sheep produced enterotoxins than those from goats and cattle. SEC was the predominant type in all isolates from these animal species. The highest proportion of strains producing TSST‐1 were obtained from sheep, twice as many as those from goats or cows. The two techniques gave similar results. as all the strains positive by immunoblot were also positive by ELISA, and only three were positive by ELISA but negative by immunoblot.
Oxygen and pyruvate as external electron acceptors for Leuconostoc spp.
Authors: Nuraida L. , Grigolava I. , Owens J.D. , Campbell‐Platt G.
Published: March 2008

L. NURAIDA, I. GRIGOLAVA, J.D. OWENS AND G. CAMPBELL‐PLATT. 1992. Leuconostoc mesenteroides NCDO 518, Leuc, mesenteroides NCIB 8710, Leur. mesenteroides NCIB 8023, Leuconostoc sp. Pz 45, Leuconostoc sp. Pz 34 and Leuconostoc sp. Pz 10 were grown in a chemically defined medium with glucose and different external electron acceptors. All strains, except Leuconostoc sp. Pz 10, formed acetate under aerobic conditions. Leuconostoc Pz 10 produced only small amounts of acetate under aerobic or anaerobic conditions. This strain was the only strain not possessing NADH oxidase. All strains produced acetate from a mixture of glucose plus pyruvate. None of the bacteria used glycerol. Oxygen and pyruvate as external electron acceptors increased the cell yield on glucose.
Effect of benzonitrile ester herbicides on the growth of some soil bacteria
Authors: Cserháti T. , Illés Z. , Nemes‐Kósa S.
Published: March 2008

T. CSERHÁTI, Z. ILLÉS AND S. NEMES‐KÓSA. 1992. The effect of some benzonitrile ester herbicides on the growth of Bacillus megaterium, B. cereus var. mycoides, B. polymyxa, B. subtilis, Pseudomonas fluorescens and Azotobacter chrooccum was investigated in the concentration range 20–640 ppm by the agar diffusion method. The zones of inhibition, restricted growth and eventual stimulation were determined. The data matrix was evaluated by principal component analysis. Azotobacter chroococcum was the most resistant to the benzonitrile esters. The influence of benzonitrile esters on the growth of micro‐organisms depended equally on the species and on the chemical structure of the herbicides. Chloro substitution considerably modified the effect whereas bromo and iodo substitution resulted in similar biological activity.
Further studies on some physical and biochemical characteristics of asaccharolytic pigmented Bacteroides of feline origin
Authors: Collings Susan , Love Daria N.
Published: March 2008

S. COLLINGS AND D.N. LOVE. 1992. The ultrastructure of the appendages of 24 strains of asaccharolytic pigmented Bacteroides spp. of cats was studied by transmission electron microscopy. All strains examined by thin section showed abundant fimbriae, outer membrane vesicles and capsules. Negative staining showed fimbriae which varied from long, fine and wavy in Bact. salivosus and cat Group 2 to shorter, less abundant and thicker fimbriae in cat strains of Bact. gingivalis as well as type strains of Porphyromonas gingivalis and P. asaccharolytica. Capsular material was very thick amorphous in human P. gingivalis, cat strains of Bact. gingivalis and in P. assaccharolytica but fine and fibrillary in preparations of Bact. salivosus and cat Group 2 organisms. Wet india ink preparations showed a large capsule although those of Bact. salivosus and Group 2 appeared largest. Five‐day Group 2 broth cultures featured a thick ropy growth consistent with a large accumulation of extracellular slime. Enzymatic activities of the 24 strains measured by API ZYM system as well as the conventional biochemical tests showed it was possible to differentiate reliably Bact. salivosus from the other cat strains of asaccharolytic pigmented Bacteroides species and from human P. gingivalis and P. endodontalis by a combination of these tests. These tests suggest that Bact. salivosus is unlikely to belong to the genus Prevotella. Its place within the genus Porphyromonas is still to be determined.
Microbiological events during commercial meat fermentations
Authors: Marchesini Barbara , Bruttin Anne , Romailler Nicole , Moreton R.S. , Stucchi C. , Sozzi T.
Published: March 2008

Microbiological developments during industrial meat fermentations (salami), made with and without commercial starter cultures, were followed at two factories in Germany and Italy. In the German product microbial growth was evident only for the first 48 h, followed by a gradual decline in numbers of most micro‐organisms. The pH fell from 5.8 to 4.8 in the 28 d required for production. In Italy a similar situation was seen, except that a second period of bacterial growth began around 15 d, coincident with the appearance of intentional surface mould growth which reversed the pH fall, the final pH being 6.2. The German starter culture was a mixture of Lactobacillus plantarum and Staphylococcus carnosus, whereas in Italy only Staph. carnosus was used. The strain of Lact. plantarum used did not grow in the German product whereas the Staph. carnosus grew well in both products to form a substantial proportion of the final microflora.
Lactose metabolism and lactase gene sequence homologies amongst lactobacilli
Authors: Collins M.A. , Thompson J.K.
Published: March 2008

A number of strains of Lactobacillus spp., including the thermophilic and mesophilic dairy species, were screened for the presence of β‐galactosidase (β‐gal) and phospho‐β‐galactosidase (pbg) enzyme activities. The majority of lactose fermenting strains exhibited β‐gal rather than pbg enzyme activity with the highest levels in the thermophilic dairy species.

Correlation between these enzymes and the presence of specific genetic determinants was sought using probes for β‐gal and pbg genes from Lactobacillus casei ssp. casei strain 64H. Southern transfer and filter hybridization showed that the β‐gal probe shared homology with one strain of Lact. casei ssp. casei only. Sequences homologous to the pbg gene were detected only in plasmid DNA from the same strain of Lact. casei ssp. casei and with plasmid DNA from an apparently unrelated strain of Lactobacillus which exhibited no pbg activity. Two other strains of Lact. casei ssp. casei appeared to show homology between their chromosomal DNA and the pbg gene probe. No other homologies were detected. Therefore, although lactase activity could be detected in many strains of Lactobacillus spp., the genetic determinants involved did not share extensive homology.
Enterococcal and streptococcal species isolated from faeces of calves, young cattle and dairy cows
Authors: Devriese L.A. , Laurier L. , Herdt P. De , Haesebrouck F.
Published: March 2008

Faeces from non‐ruminating calves were found to contain several species of enterococci: Enterococcus avium, Ent. cecorum, Ent. durans, Ent. faecalis, Ent. faecium and Ent. hirae. Enterococcus faecalis was the most frequent. Few of these animals carried streptococci.

Streptococcus bovis largely predominated in ruminating calves, young cattle and dairy cows. Other streptococci as well as enterococci were infrequent in dairy cows, but a variety of other streptococci and enterococci were found in the faeces of young ruminating animals.
Physicochemical characterization of the microbial Fe2 + chelator proferrorosamine from Pseudomonas roseus fluorescens
Authors: Woestyne M. Vande , Bruyneel B. , Verstraete W.
Published: March 2008

M. Vande Woestyne. B. Bruyneel and w. Verstraete. 1992. The microbial chelating compound proferrorosamine A, produced by Pseudomonas roseus fluorescens, formed a complex with Fe2 + of which the apparent stability constant was found to be 1023. The following order of increasing stability constants of metal complexes with proferrorosamine was established as: Ba2+, Ca2 +, Mg2+, Mn2+ < Hg2+ < Zn2+ < Pb2+ < Co2+ < Cu2 +∼ Fe2 + < Ni2+. Only Ni2 +‐proferrorosamine had a stability constant which was established as: Ba2+, Ca2+, Mg2+, Mn2+ < Hg2+ < Zn2+ < Pb2 + < Co2 + < Cu2 +∼ Fe2 + < Ni2 +. Only Ni2+‐proferrorosamine had a stability constant which was ca 32 times higher than Fe2 +‐proferrorosamine. Because of the production of proferrorosamine the growth of Ps. roseus juorescens was not inhibited in iron limiting media by the addition of 0.15 mmol/l of the weaker chemical Fe2 + chelator 2,2′‐dipyridyl. This contrasted with the proferrorosamine‐negative mutant K2 and Ps. stutzeri, which only produces Fe3+‐chelating siderophores. Furthermore, it was found that proferrorosamine was able to dissolve Fe2+ from stainless steel. These results show that proferrorosamine is a strong and selective Fe2+ chelator which could be used as an alternative for the toxic 2,2′‐dipyridyl to control lactic acid fermentations.
Comparison of fermentation reactions in different regions of the human colon
Authors: Macfarlane G.T. , Gibson G.R. , Cummings J.H.
Published: March 2008

Colonic contents were obtained from two human sudden‐death victims within 3 h of death. One of the subjects (1) was methanogenic, the other (2) was a non‐CH, producer. Measurements of bacterial fermentation products showed that in both individuals short‐chain fatty acids, lactate and ethanol concentrations were highest in the caecum and ascending colon. In contrast, products of protein fermentation, such as ammonia, branched chain fatty acids and phenolic compounds, progressively increased from the right to the left colon, as did the pH of gut contents. In Subject 1, cell population densities of methanogenic bacteria (MB) increased distally through the gut and methanogenic activity was lower in the right (0.78–1–18 μmol CH4 produced/h/g dry wt contents) than in the left colon (1.34 μmol CH4 produced/h/g dry wt contents). Methane production rates did not correlate with MB numbers.

Sulphate‐reducing bacteria (SRB) were not found and dissimilatory sulphate reduction was not detected in any region of the colon. Methanogenic bacteria did not occur in subject 2, but high numbers of SRB were present throughout the gut (ca 109/g dry wt contents). Sulphate reduction rates were maximal in the ascending and transverse colons (0.24 and 0.22 μmol 35SO2–4 reduced/h/g dry wt contents, respectively). Short‐chain fatty acid production by caecal contents was up to eight‐fold higher than contents from the sigmoid/rectum. These findings demonstrate significant differences in fermentation reactions in different regions of the large gut.
A note on the use of a plasmid as a DNA probe in the detection of a Lactobacillus fermentum strain in porcine stomach contents
Authors: Tannock G.W. , McConnell Michelle A. , Fuller R.
Published: March 2008

A plasmid (about 50 kb) was used as a DNA probe to enumerate, by colony hybridization, a strain of Lactobacillus fermentum in the stomach contents of eight piglets. The population sizes obtained by colony hybridization were in agreement with estimated levels calculated on the basis of plasmid profiling of colonies isolated at random from the total lactobacillus population.
Purification to homogeneity of extracellular polygalacturonase and isoenzymes of pectate lyase of Erwinia carotovora subsp. atroseptica by column chromatography
Authors: McMillan G.P. , Johnston D.J. , Pérombelon M.C.M.
Published: March 2008

Extracellular polygalacturonase (PG) and two pectate lyase isoenzymes (PLI and PLII) produced by a 48 h culture of Erwinia carotovora subsp. atroseptica in pectate‐based medium were purified 2027, 2036 and 2374‐fold respectively to homogeneity with corresponding 59%, 61% and 32% recovery. This was achieved first by ion exchange chromatography on a S‐Sepharose fast flow column with 20 mmol/1 Tris at pH 8.0 followed by elution of bound proteins with a 1 mol/1 NaCl gradient which separated PG from PL. The two enzymes were then further purified to homogeneity (assessed by SDS‐PAGE) by selective adsorption chromatography on a hydroxyapatite column equilibrated with distilled water; PG was eluted with a 3 mol/1 KCl gradient and PLI with a 3 mol/1 KCl gradient followed by a 1.2 mol/1 PO4 buffer pH 6.5 gradient to elute PLII. The Mr of the three enzymes determined by SDS‐PAGE was 39 kDa and the pI values for PG, PLI and PII were 10.3, 10.3 and 10.0 respectively as determined by isoelectric focusing (IEF)‐gel electrophoresis followed by activity staining.