bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.INTRODUCTIONDietary 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).
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.
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.
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.
Detection of irradiated deep‐frozen foodstuffs by comparison of DEFT and APC counts
Authors: Copin Marie‐Pierre , Jehanno Dominique , Bourgeois C.M. 
Published: March 2008

The suitability of a microbiological method based on the comparison of an aerobic plate count (APC) with a count obtained with the direct epifluorescent filter technique (DEFT) for the detection of irradiation of deep‐frozen foodstuffs was evaluated. The study was carried out on parsley, mechanically deboned poultry meat (MDPM) and liquid egg white. The foodstuffs were stored at—18°C and examined after storage for 0, 4 and 12 months.The results showed that this method is discriminating during the whole storage period. Nevertheless, it has been observed that for non‐irradiated liquid egg white the difference between DEFT and APC tends to increase with the time of storage. This phenomenon which did not limit the interest of the test, was not observed for the other products tested.
Electrotransformation of meat lactobacilli. Effect of several parameters on their efficiency of transformation
Authors: Aymerich M.T. , Hugas M. , Garriga M. , Vogel R.F. , Monfort J.M. 
Published: March 2008

Intact cells of several lactobacilli isolated from Spanish dry fermented sausages (Lactobacillus curvatus, Lact. sake, Lact. plantarum and Lact. bavaricus) were transformed by electroporation. With pNZ12 as a vector, transformation efficiencies of 2.4 times 105, 3.8 times 103 and 8.8 times 102 transformants μg‐1 DNA were observed for Lact. curvatus CTC435, Lact. sake CTC335 and Lact. bavaricus CTC232, respectively.Effects of variation in experimental parameters on transformation efficiency were evaluated. Strains, vectors and buffers were the determinant parameters. The growth phase of the culture, cell concentration, voltage, use of cell wall weakening agents and the purity of the vector influenced the transformation efficiency in most strains.
Deoxyribonucleic acid relatedness of 21 strains of Xanthomonas species and pathovars
Authors: Palleroni N.J. , Hildebrand D.C. , Schroth M.N. , Hendson M. 
Published: March 2008

The relationship of 17 Xanthomonas campestris pathotype strains, three additional X. campestris strains, and the type strain of Xanthomonas albilineans were examined by DNA‐DNA hybridization tests. The results coupled with those of a previous study (Hildebrand et al. 1990) support the hypothesis that X. campestris does not constitute a single bacterial species. There were low levels of DNA‐DNA reassociation among many of the different pathovars examined. Six clusters of related pathovars were discerned. In addition, four of the pathovars were only distantly related to each other and to the six clusters. Xanthomonas albilineans was not closely related to any of the other xanthomonads tested.Mapping and superimposing the botanical families of the host plants upon a three‐dimensional genomic distance matrix of the xanthomonads confirms previous observations that pathovars that infect plants of the same botanical family do not necessarily belong to the same genomic group. Six legume‐infecting pathovars cluster within one genomic group, but one pathovar, X. cam. pv. pisi is only distantly related to this group. There was also no genomic relationship between X. cam. pv. oryzicola and X. albilineans both of which infect Gramineae. Consequently, pathogenicity toward members of the same plant family is not a good indicator of the genomic relationships among xanthomonads nor is it a good taxonomic determinant.
Isolation of a DNA probe for identification of glucan‐producing Pediococcus damnosus in wines
Authors: Lonvaud‐Funel Aline , Guilloux Y. , Joyeux Annick 
Published: March 2008

Some Pediococcus damnosus strains isolated from spoiled wines were able to synthesize polysaccharide and increased viscosity. Three strains lost their ropy phenotype relatively frequently during successive transfers in a non‐alcoholic medium. They could not recover it when cultured in the presence of ethanol. Plasmid pattern comparison showed these variants had lost some of their plasmid DNA. Both ethanol and the plasmid were required to induce polysaccharide synthesis.Plasmid DNA of a wild strain was cloned into Escherichia coli with pTZ18R and pBR 322. Specific clones were selected by differential hybridization of transformed E. coli with plasmid DNA from a ropy strain and its non‐ropy variant. Clones which hybridized with total plasmid DNA from the ropy strain and not with that of the non‐ropy strain carried an insert of the plasmid involved. One of these was chosen. Its DNA proved to be specific and usable as a probe in identifying and detecting ropy Ped. damnosus strains.
Purification, partial characterization and plasmid‐linkage of pediocin SJ‐1, a bacteriocin produced by Pediococcus acidilactici
Authors: Schved F. , Lalazar A. , Henis Y. , Juven B.J. 
Published: March 2008

Pediococcus acidilactici SJ‐1, isolated from a naturally‐fermented meat product, produced an antibacterial agent active against selected strains of Lactobacillus spp., Clostridium perfringens and Listeria monocytogenes. The agent was bactericidal against sensitive indicators, and sensitive to proteolytic enzymes; it was identified as a bacteriocin, and was designated as pediocin SJ‐1. It was stable over a wide pH range (3–9), and apparently most stable in the lower part of that range. At pH 3.6, pediocin SJ‐1 was stable at heat‐processing temperatures within the range 65–121°C; its activity decreased significantly, however, when it was heated at pH 7.0. The activity of pediocin SJ‐1 on sensitive indicator cells was lost in the presence of α‐amylase, suggesting that it contains a glyco moiety, necessary for its antibacterial action.Native pediocin SJ‐1 exists in the form of monomers and aggregates (with molecular weights in the range 80–150 kDa). Pediocin SJ‐1 was purified 262‐fold by direct application of cell‐free supernatant fluids to a cation‐exchange chromatography column, and was resolved by SDS‐PAGE as a single peptide band with a MW of ca 4 kDa. The original pediocin SJ‐1‐producing strain (bac+) harbours three plasmids of 4.6, 23.5, and 45.7 MDa. Production of pediocin SJ‐1, but not immunity to SJ‐1, is associated with the 4.6 MDa plasmid.
Effect of formulation pH and storage temperatures on the preservative efficacy of some gases used as propellants in cosmetic aerosols
Authors: Ibrahim Y.K.E. , Sonntag H.‐G. 
Published: March 2008

The effects of changes in formulation pH and storage temperature on the preservative activities of some aerosol propellants—butane, carbon dioxide, dimethylether and their combinations were investigated. A preservative challenge test method was used to determine the survival rates of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus niger at formulation pH levels 5·80, 7·28 and 8·10 and storage temperatures of 20°, 30° and 40°C.A significant decrease in the pH of formulations was observed with no corresponding changes in the antimicrobial effectiveness when carbon dioxide was incorporated. Alterations in the antimicrobial profiles of these propellants due to changes in formulation pH were dependent on the propellant and the species of the micro‐organism, especially when single propellants were used. Results also showed that the propellants exert antimicrobial activities against the various organisms at the three storage temperatures but there were significantly greater inhibitory activities at 40°C. With a combination of 10% butane/dimethylether (1:2) and 10 bar carbon dioxide there were no differences in the degree of microbial inhibition at the various formulation pH levels and storage temperatures. In most cases, the organisms were completely inactivated within 24 h. These findings showed that the combination of butane/dimethylether with carbon dioxide could be used to protect against microbial contamination and spoilage of formulations of different pH levels as well as those meant for storage at different temperatures.
A simple, rapid and sensitive presence/absence detection test for bacteriophage in drinking water
Authors: Armon R. , Kott Y. 
Published: March 2008

R. ARMON AND Y. KOTT. 1993. A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. The entire device was incubated in a water bath at 36d̀C.Plaques of somatic bacteriophage infecting Escherichia coli strain CN13, could be detected within 3 h. Male‐specific bacteriophages infecting E. coli F+ amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one‐step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples.
External quality assessment in water microbiology: statistical analysis of performance
Authors: Tillett Hilary E. , Lightfoot N.F. , Eaton Sheila 
Published: March 2008

H.E. TILLETT, N.F. LIGHTFOOT AND S. EATON. 1993. A UK‐based scheme of water microbiology assessment requires participants to record counts of relevant organisms. Not every sample will contain the target number of organisms because of natural variation and therefore a range of results is acceptable. Results which are tail‐end (i.e. at the extreme low or high end of this range) could occasionally be reported by any individual laboratory by chance. Several tail‐end results might imply a laboratory problem. Statistical assessment is done in two stages. A non‐parametric test of the distribution of tail‐end counts amongst laboratories is performed (Cochran's Q) and, if they are not random, then observed and expected frequencies of tail‐end counts are compared to identify participants who may have reported excessive numbers of low or high results.Analyses so far have shown that laboratories find high counts no more frequently than would be expected by chance, but that significant clusters of low counts can be detected among participants. These findings have been observed both in short‐term and in long‐term assessments, thus allowing detection of new episodes of poor performance and intermittent problems.The analysis relies on an objective definition of tail‐end results. Working definitions are presented which should identify poor performance in terms of microbiological significance, and which allow fair comparison between membrane‐filtration and multiple‐tube techniques. Smaller differences between laboratories, which may be statistically significant, will not be detected. Different definitions of poor performance could be incorporated into future assessments.
Stability of plasmids in five strains of Salmonella maintained in stab culture at different temperatures
Authors: Olsen J.E. , Brown D.J. , Baggesen Dorte L. , Bisgaard M. 
Published: March 2008

Four strains of Salmonella berta and one of Salm. enteritidis were stored as stab cultures in sugar‐free agar at 5°, 22° and 30°C and in 15% glycerol at—80°C. The stability of the plasmid profiles in each of the strains was monitored over a period of 2·5 years.Plasmid profiles were stable in all strains stored at—80°C, and only six of 450 colonies examined from strains kept in sugar‐free agar at 5°C had lost plasmid molecules. Seventy of 440 colonies from stab cultures that were kept at 22°C, and 71 of 440 colonies at 30°C showed changed plasmid profiles. The total number of plasmids lost increased with time, and occasionally, more than one plasmid molecule was lost in the same strain.The virulence associated plasmid of Salm. enteritidis was remarkably stable as it was maintained in all colonies examined at all temperatures investigated. Likewise, no change in SmaI restriction profile was observed in this plasmid molecule at any temperature.
Antibiotic production and biocontrol activity by Bacillus subtilis CL27 and Bacillus pumilus CL45
Authors: Leifert C. , Li H. , Chidburee Siripun , Hampson S. , Workman Suzanne , Sigee D. , Epton H.A.S. , Harbour Agnes 
Published: March 2008

C. LEIFERT, H. LI, S. CHIDBUREE, S. HAMPSON, S. WORKMAN, D. SIGEE, H.A.S. EPTON AND A. HARBOUR. 1995. Bacillus subtilis CL27 and B. pumilus CL45 showed similar activity against Botrytis cinerea in in vitro plate assays. In a seedling bioassay, however, B. subtilis CL27 had activity similar to a commercial fungicide while B. pumilus CL45 failed completely to prevent seedling damping‐off caused by Bot. cinerea.Antibiotic production by the two Bacillus strains was found to depend on the growth substrate and highest antibiotic production was found on media based on homogenized cabbage tissue. Antibiotic activity was found to depend on the pH and nutrient concentration in the assay medium. Antifungal antibiotics produced by B. subtilis CL27 and B. pumilus CL45 in different fermentation media were separated by thin layer chromatography. As suspected from the activity spectrum, three antibiotics (one with activity against Alternaria brassicicola, one with activity against Botrytis cinerea and one with activity against both fungi) could be detected in the fermentation broth of CL27, but only one in the fermentation broth of CL45. The two antibiotics produced by strain CL27 with activity against A. brassicicola were identified as peptides since their bands on the TLC plates developed a green to blue/green colour after treatment with 4,4'‐tetramethyldiamino‐diphenylmethane (TDM) reagent. The third antibiotics produced by strain CL27 and antibiotic produced by CL45 had a similar Rf‐value and appeared not to be peptides based on the reaction with TDM. However, they showed a slightly different activity spectrum when tested against a range of different fungi.Antibiotic production was clearly indicated as the mode of action of in vivo biocontrol by strain CL27 against damping off caused by Bot. cinerea of Astilbe micro‐plants, because a u.v.‐induced antibiotic negative mutant strain CL27b showed no activity in seedling bioassays in vivo. Also the mutant strain CL27a which produced the two peptide antibiotics but had lost the ability to produce the non‐peptide antibiotic, showed greatly reduced in vivo activity.
Bioremediation of colour of methyl violet and phenol from a dye‐industry waste effluent using Pseudomonas spp. isolated from factory soil
Authors: Sarnaik S. , Kanekar P. 
Published: March 2008

Methyl violet, a basic dye, is manufactured using phenol and dimethylaniline as the raw materials. It is, therefore likely that the waste effluent arising from such units may contain the dye and unused chemicals. Since such pollutants may be toxic, their removal becomes necessary. The studies were therefore aimed at their bioremediation using microbial species.Four species of Pseudomonas, namely Ps. alcaligenes, Ps. mendocina, Ps. putida biovar B and Ps. stutzeri, were isolated from cattle dung enrichments and the soil samples in the premises of the factory manufacturing methyl violet, nearby Pune.All the four species of Pseudomonas were able to remove phenol and methyl violet with simultaneous reduction in chemical oxygen demand (COD), total organic carbon (TOC) and ammoniacal nitrogen from the waste effluent and the removal was found to be optimum at the original alkaline pH (range 7.45–10.6) of the waste effluent, at ambient temperature (28 ± 2°C under aerated culture condition, at inoculum density of 1.5 × 108 cells ml−1 of the waste effluent and incubation period of 24–48 h. Thus, Pseudomonas spp. isolated from the environment of the dye industry itself and thus naturally adapted could be used for bioremediation of these pollutants.