bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peat Culture of Rhizobium trifolii: an Examination by Electron Microscopy
Authors: Dart P. J. , Roughley R. J. , Chandler Muriel R. 
Published: March 2008

SummaryPeat cultures of Rhizobium trifolii strain TA1 were examined by electron microscopy of thin sections of aldehyde‐OsO4 fixed Araldite embedded particles, and scanning reflection electron microscopy of the peat particle surfaces. The Badenoch peat used showed plant cell wall fragments; membranes with dense‐light‐dense appearance in vesicular or linear form; tubular structures; other unidentified wall‐like fragments, all usually surrounded by a matrix of varying electron density and granularity. The general level of electron density was high, even in plant wall fragments, although some electron‐transparent spaces were present in the matrix. Remains of bacteria and actinomycetes were often found within the peat particles. Particle shape varied a great deal; the surface was irregular with many crevices. Rhizobium cells were found on the surfaces, and sometimes in crevices of the particles. Rarely > 10 cells were found together and the cells were usually several μm apart. The rhizobia were structurally similar to broth cultured log phase cells, but often the region between cell wall membrane and plasma membrane was very electron dense. The rhizobia were usually enmeshed in a fibrillar matrix connecting them to the peat particles; this was probably the film seen to cover the bacteria in scanning surface pictures.
On the Growth and Survival of Clostridium septicum in Soil
Authors: Garcia M. M. , McKay K. A. 
Published: March 2008

SummaryClostridium septicum was inoculated into soils treated in different ways and samples were removed periodically for microbial analyses by one or more of the following methods: plate counts, fluorescent antibody staining, dehydrogenase activity and manometric techniques. Mass sporulation of the vegetative cells was not triggered initially when inoculated into amended soils. Moreover, the vegetative forms persisted in both sterile and unsterile soils for up to 30 days in incubated samples. Glucose, pyruvate, peptone and manure enhanced the growth and metabolic activity of Cl. septicum in soil. Wyoming bentonite tended to decrease dehydrogenase activity whereas Georgia kaolinite had no detectable effect. The significance of organic matter addition and type of clay mineral on the ecology of Cl. septicum is discussed.
Physiological and Morphological Characteristics of Kurthia zopfii Isolated from Meat Products
Authors: Gardner G. A. 
Published: March 2008

SummaryKurthia zopfii was frequently isolated from meats, especially comminuted meats. Its proportion of the aerobic flora in such products at the point of production did not generally exceed 10%. It is not known to cause spoilage of refrigerated meats, but there is some evidence to suggest that its presence in the flora is indicative of high temperatures during the production, distribution, etc., of the product. Morphological and physiological characteristics of K. zopfii were examined, and it was found that the species could be divided into two distinct groups. There was no association between the group and the product from which it was isolated.
Lysis of Bacterial Spores with Hydrogen Peroxide
Authors: King W. L. , Gould G. W. 
Published: March 2008

SummarySpores of Bacillus cereus were made sensitive to lysis with H2O2 by treatment with reagents which break disulphide bonds (e.g. thioglycollic acid), by incubation with reagents which break hydrogen bonds (e.g. urea and lithium bromide) or by incubation at high temperatures. However, treated spores lost viability in the presence of H2O2 at the same rate as did untreated spores. Lysis was optimal at high pH values and in the presence of metal ions, e.g. Cu2+, suggesting that lysis was caused by free radicals formed by metal catalysed decomposition of the peroxide. Isolated spore coats, in contrast to whole spores, were lysed by H2O2 even when not pretreated. and the immediate products of spore coat lysis were soluble proteins; on continued incubation with H2O2 these proteins were degraded to low MW peptides and amino acids. It appeared that whole spores resisted lysis because peroxide sensitive bonds were masked by compact tertiary molecular structures, and that the sensitizing agents were able to loosen these structures sufficiently to expose bonds sensitive to H2O2.
Fine Structure of Methane‐utilizing Bacteria
Authors: Proctor Heather M. , Norris J. R. , Ribbons D. W. 
Published: March 2008

Summary.Thin sections of methane‐utilizing bacteria have been examined in the electron microscope and the fine structure of the cells is described for the first time. The outstanding feature of all the isolates studied is the existence of intracellular membrane structures resembling those seen in nitrifying and photosynthetic bacteria. The possible significance of these membranes is discussed.
Trace Elements and Reproduction of Leptospirae
Authors: Burger G. , Fuchs G. H. P. 
Published: March 2008

Summary.Low concentrations of Zn and Co salts in the medium stimulated growth of several strains of 2 species of Leptospira, but high concentrations inhibited growth. Low concentrations of Cu increased the growth rate of saprophytic leptospirae but did not affect parasitic strains; high concentrations inhibited all strains. In a Zn‐containing medium, the addition of increasing amounts of Cd was increasingly inhibitory to both speeies. The addition of 0·2 × 10−6 gof Zn(NO3)2. 6H2O and 10−9 gofCoSO4. 7H2O/ml of Korthof's medium is recommended. Saprophytic leptospirae grow better with 10−6g of CoSO4. 5H2O/ml of medium.
Viability of Clostridial Spores and the Requirements of Damaged Organisms
Authors: Futter B. V. , Richardson G. 
Published: March 2008

Summary.Viable counts of spores surviving exposure to bactericidal influences were higher in nitrogen than in hydrogen. The relationship between the nitrogen and hydrogen counts was dependent on the bactericidal pretreatment. Two species showed a cysteine dependence which was probably not due to its effect on Eh. Low concentrations of carbon dioxide caused a reduction in count.
Tetrad‐forming Cocci in Ciders
Authors: Carr J. G. 
Published: March 2008

Summary.A tetrad‐forming coccus isolated from a ropy cider was characterized and identified with Pediococcus cerevisiae. This organism occurs both as a slime‐forming and non‐slime‐forming strain, the former being of considerable economic importance if it grows in stored cider. Some factors affecting slime formation have been investigated and are herein reported. The question of whether the generic names Pediococcus and Streptococcus should be merged is also discussed.
Aspects of the Action of Glutaraldehyde on Escherichia coli
Authors: Munton T. J. , Russell A. D. 
Published: March 2008

Summary.Glutaraldehyde did not cause lysis of spheroplasts of Escherichia coli or of protoplasts of Bacillus megaterium. Its bactericidal activity against E. coli was potentiated in the presence of sodium bicarbonate or alkaline phosphate buffer. Over long periods, the uptake of aldehyde by E. coli increased when sodium bicarbonate was present. Glutaraldehyde with, but not without, sodium bicarbonate produced with E. coli cells a red colouration which was associated with the cell wall.
Oxytetracycline‐Glucose‐Yeast Extract Agar for Selective Enumeration of Moulds and Yeasts in Foods and Clinical Material
Authors: Mossel D. A. A. , Kleynen‐Semmeling A. M. C. , Vincentie H. M. , Beerens H. , Catsaras M. 
Published: March 2008

Summary.The oxytetracycline‐glucose‐yeast extract agar of Mossel, Visser & Mengerink (1962) for the selective enumeration of moulds and yeasts in foods has been extensively tested on 4000 samples of various materials in two food microbiology and one clinical laboratory. Its performance was excellent in that it suppressed entirely the growth of Bacillaceae. Only when examining stools from patients under tetracycline therapy did the medium insufficiently inhibit Enterobacteriaceae. Substitution of oxytetracycline by 50 μg/ml of gentamicin was useful in such instances.
Pseudomonas viridiflava (Burkholder, 1930; Clara 1934)
Authors: Billing Eve 
Published: March 2008

Summary.The characteristics of 12 isolates from 7 different hosts which were believed to be Pseudomonas viridiflava were studied using a variety of cultural and biochemical tests; in nutritional tests, 135 compounds were screened for their ability to serve as sole carbon and energy (C/E) sources. All cultures were similar in character and resembled closely Burkholder's original isolates: they were distinguishable from 13 cultures of other phytopathogenic Pseudomonas spp. Although they closely resembled Ps. syringae, they could be distinguished by their ability to rot potato, to utilize d(—) tartrate as sole C/E source and by their failure to utilize sucrose and to form levan on 5% sucrose nutrient agar. Pseudomonas viridiflava is a common epiphyte at least on dwarf beans (Scarlett, 1968) though it has rarely been cited as a cause of disease in Phaseolus spp. Results of lesion tests in dwarf bean pods and in the tobacco hypersensitivity test together with pectolytic activity strongly suggest however that it is a potential pathogen.
The Effect of Hibernation on the Caecal Flora of the Thirteen‐lined Ground Squirrel (Citellus tridecemlineatus)
Authors: Barnes Ella M. , Burton Glenna C. 
Published: March 2008

Summary.The effect of hibernation on the caecal flora of the thirteen‐lined ground squirrel (Citellus tridecemlineatus) was determined by comparing the flora of 7 active squirrels with that of 6 × 6 days hibernators and 2 × 42 days hibernators. Direct microscopical examination showed the presence of a wide variety of micro‐organisms, including protozoa in all the animals. Using strict anaerobic techniques it was possible to isolate > 60% of the total flora of the active squirrels but only c. 30% in the hibernators. Several distinct types of anaerobic Gram negative, nonsporing rods predominated in both the active and hibernating animals. Gram positive, nonsporing rods and coccobacilli were present in the active squirrels but were not isolated from the 42 days hibernators. Atypical lactobacilli present at 106–108/g formed the major part of the aerobic flora of the active squirrels but were reduced at least 100‐fold during hibernation.
The Effect of Water Activity on the Heat Resistance of Heat Sensitive and Heat Resistant Strains of Salmonellae
Authors: Baird‐Parker A. C. , Boothroyd Margery , Jones E. 
Published: March 2008

Summary.A strain of Salmonella senftenberg and a strain of Salm. bedford have been found with D60° values similar to that of the classical heat resistant salmonella, Salm. senftenberg strain 775W. The resistances of the two heat resistant serotypes and two heat sensitive strains of these serotypes was determined in heart infusion broth containing increasing amounts of sucrose, sodium chloride or glycerol. The observed changes in heat resistance could not be related directly to the aw of the heating menstruum. It is impossible to predict from such studies the heat resistance of salmonellae in foods of low aw.
Total Counts of Bacillus megaterium and Clostridium butyricum Spore Suspensions using a Microlitre Syringe
Authors: Marshall Anne C. , Rigby G. J. 
Published: March 2008

Summary.A method for making total counts based on counting every organism in a small accurately measured volume of a suspension, using the microlitre syringe and phase contrast microscopy, has been described. Total counts of a Bacillus megaterium and a Clostridium butyricum spore suspension made by this method have been compared with haemocytometer chamber counts. The syringe method, although tedious, has the advantage that extraneous particles are easily identified. In certain circumstances a total and a colony count can be done on the same suspension using the syringe to deliver the same volume for both counts. The low percentage colony counts of many spore suspensions are probably not related to errors in the total counts, nor to manipulative errors in the colony counts, but are more probably related to the composition of the medium used for the colony counts.
The Precipitation of Calcium Carbonate from Seawater by Bacteria Isolated from Bahama Bank Sediments
Authors: McCallum May F. , Guhathakurta Kishwar 
Published: March 2008

Summary.Precipitation of calcium carbonate by marine isolates from Bahamian sediments was studied in several media and under different experimental conditions. Almost all cultures brought about precipitation of aragonite crystals. The role of bacteria in the precipitation of CaCO3 in the marine environment is discussed.
Ultrasonic Dispersal of Activated Sludge Floes
Authors: Williams A. R. , Stafford D. A. , Callely A. G. , Hughes D. E. 
Published: March 2008

Summary.A novel device which could be used for the disruption of activated sludge flocs, using a transversely oscillating wire, is discussed. The acoustic microstreaming generated around the wire produced hydrodynamic shear forces sufficiently strong to break up sludge flocs, without causing a loss in viability of the component cells. A 20‐fold increase in total heterotrophs and Thiobacillus‐type organisms was observed. Electron micrographs provided visual evidence for the disruption of flocs.
A Note on the Development of Resistance to Heat and Gamma Radiation in Salmonella
Authors: Corry Janet E. L. , Roberts T. A. 
Published: March 2008

Summary.Repeated heat treatment and subculture increased the heat resistance of one strain of Salmonella typhimurium with no apparent increase in pathogenicity, or significant change in common biochemical characters. Cycling to γ radiation produced similar results. Re‐cycled strains contained extremely low proportions of the smooth colonies required for serological and phage typing.
Adenosinetriphosphate (ATP) Levels in Foods Contaminated by Bacteria
Authors: Sharpe A. N. , Woodrow M. N. , Jackson A. K. 
Published: March 2008

Summary.ATP levels were determined in micro‐organisms and in foods, either as purchased or after incubation or addition of living bacteria. ATP levels in foods were divided into intrinsic ATP (derived from the original tissue) and microbial ATP. Intrinsic ATP decreased during incubation while bacterial ATP increased. At sufficiently high levels of contamination ATP levels could be related to bacterial concentrations.
A Novel Selective Method for the Production of Bacillus subtilis var. niger Spores
Authors: Evans C. G. T. , Harris‐Smith R. 
Published: March 2008

Summary.A method for the recurrent selective production of heat resistant spores of Bacillus subtilis var. niger is described. The method embodies some features of both batch and continuous culture, permitting a daily production of 10 1 volumes of culture containing up to 2·3 × 1010 spores/ml. These spores are stable in storage at −20° and yet germinate readily, giving rise to easily recognizable, pigmented colonies.
The Microbial Associations in British Fresh Sausages
Authors: Dowdell Marilyn J. , Board R. G. 
Published: March 2008

Summary.British fresh sausages, both pork and beef, contain climax populations consisting of Microbacterium thermosphactum, yeasts, lactobacilli and micrococci. The multiplication of lactobacilli and micrococci is a feature of sausages held at room temperature. The rate of growth of the other organisms decreased as the temperature of storage was lowered. The extent of growth of M. thermosphactum was inversely related to the initial load of contaminants of freshly prepared sausage meat. The yeasts appeared to be an independent component of the microbial associations. The growth of lactobacilli was favoured by a heavy initial infection of sausage meat. With the exception of lactobacilli, organisms situated at the surface of the sausage grew more quickly and formed larger populations than those at the centre; the lactobacilli formed populations of about the same size at both locations. There was a slow decrease in pH value (pH 6.8–7.0 to 6.2–6.0) of sausage meat as the microbial associations developed.
The Leakage of Cations and Amino Acids from Staphylococcus aureus exposed to Moist Heat, Phenol and Dinitrophenol
Authors: Allwood M. C. , Hugo W. B. 
Published: March 2008

Summary.The leakage of K+, Na+ and amino acids from Staphylococcus aureus in an aqueous solution was studied at temperatures between 37 and 60°. The rate of efflux of K+ was temperature dependent. Above 50° an initial rapid loss of K+ was followed by a secondary and more prolonged period of efflux. 2.4‐Dinitrophenol enhanced the initial loss of K+, but not of amino acid, at all temperatures studied. Phenol, at a concentration which did not influence leakage at 37°, caused an increase in the K+ and amino acid losses at high temperatures. It also increased inactivation rates of the organism at all temperatures studied, while dinitrophenol was lethal only at lower temperatures. The importance of leakage to thermally‐induced inactivation of Staph. aureus is discussed.
Observations on the Microflora of Vacuum Packed Sliced Cooked Meat Products
Authors: Mol J. H. H. , Hietbrink Jacqueline E. A. , Mollen Henny W. M. , VAN Tinteren J. 
Published: March 2008

Summary.Bacterial contamination of vacuum packed sliced cooked meats occurred mainly on the slicing and packaging line. Various types of these products were examined after packing, after 1 week storage at 8° and near the end of their shelf life. From products of 2 brands sampled at the retailer 153 cultures were isolated and identified. The relative growth rates of most of these strains were determined at 8 and 20°. Unclassified strepto‐bacteria constitute the most important component of the microflora of vacuum packed cooked meats. With a number of strains, growth experiments in vacuum packed sliced berliner sausage were made to study the effects of temperature, % of brine, pH and nitrite. The shelf life of vacuum packed sliced cooked meats would be improved if contamination with unclassified streptobacteria could be prevented. This presumably can be achieved if cooked meats were handled and sliced in an area strictly separated from raw cured meats.
Response of Spores and Vegetative Cells of Bacillus spp. in a Hydrocarbon‐Water System
Authors: Felix J. A. , Cooney J. J. 
Published: March 2008

Summary.Nine strains of Bacillus spp. isolated from hydrocarbon fuel systems were examined for their ability to survive, multiply, sporulate and germinate in the aqueous phase of a hydrocarbon fuel‐aqueous salts medium. Vegetative cells did not survive in significant numbers. Larger inocula of vegetative cells survived better than smaller ones, suggesting that lytic products influenced survival. One isolate produced limited numbers of spores in the fuel‐salts system. Spores survived, and germinated at a slow rate. Germinated spores were capable of outgrowth and limited cell division. Thus, many Bacillus spp. isolated from fuel systems may be the progeny of spores which survived, rather than of cells proliferated or sporulated in the system. Survival patterns did not change when products of a hydrocarbon‐using bacterium were present in the medium. The data are consistent with the hypothesis that Bacillus spp. although isolated frequently from hydrocarbon systems, do not play a significant role in the ecology of such systems.
The Microbial Flora of the Rumen of Cows Fed Hay and High Cereal Rations and its Relationship to the Rumen Fermentation
Authors: Latham M. J. , Sharpe M. Elisabeth , Sutton J. D. 
Published: March 2008

Summary.The rumen microbial population associated with feeding cows 3 rations, hay alone, 20% hay/80% flaked maize and 20% hay/80% rolled barley has been examined. The differences between the hay and the cereal rations were considerable but between the cereal rations only slight. Both cereal rations provoked & large drop in the proportion of butyrivibrios, and a rise in the proportion of selenomonads, peptostreptococci, lactobacilli and bifidobacteria. The importance of these and other changes occurring in the microbial flora are discussed in relation to their possible effect on the products of the rumen fermentation.
Kinetics of Action of Nystatin on Yeast
Authors: Patel P. V. , Johnston J. B. 
Published: March 2008

Summary.Survival curves were obtained for related haploid, diploid and tetraploid strains of Saccharomyces cerevisiae, a pathogenic strain of Candida albicans and a nystatin‐resistant isolate of this strain, on exposure to a range of concentrations of nystatin. Susceptibility to nystatin decreased with increasing ploidy and was greater for Saccharomyces strains than for C. albicans strains. Death of cells was initially approximately logarithmic, but at certain concentrations some cells survived and cultures showed a subsequent growth phase.
Transport and Storage of Faeces for Bacteriological Examination
Authors: Crowther J. S. 
Published: March 2008

Summary.The survival of bacteria in specimens of human faeces transported and stored at different temperatures was examined quantitatively. No significant losses of bacteroides, bifidobacteria, viridans streptococci, Streptococcus salivarius, enterococci, enterobacteria, and clostridia were observed when 10% (w/v) suspensions of faeces in broth containing 10% (v/v) of glycerol were frozen for one month at −25, −78 or −196°; lactobacilli showed significant losses at −196°; veillonellae showed significant losses at −25°. At −12° veillonellae and enterobacteria showed significant losses. Most bacteria survived well for 24 h in undiluted faeces sent by post.
The Effects of Bile Salts Media and the Age of Inocula in Quantitative Studies of Populations of Erwinia carotovora var. carotovora and E. carotovora var. atroseptica
Authors: Pérombelon M. C. M. , Lowe R. 
Published: March 2008

Summary.Growth of Erwinia carotovora var. carotovora and E. carotovora var. atroseptica was significantly increased when bile salts were omitted from Logan's and Stewart's media. The lag and stationary phases were most, and the exponential phase was least, affected by bile salts which inhibited isolates of E. carotovora var. atroseptica more than those of E. carotovora var. carotovora. Selective media containing bile salts are therefore not suitable for enumerating populations of these organisms in soils or plant material.
Relationships between Estimates of Binding of Antimicrobial Agents by Macromolecules, based on Physicochemical and Microbiological Data: Cetylpyridinium Chloride and Polyethylene Glycol
Authors: Coates D. , Richardson G. 
Published: March 2008

ABSTRACT.Binding of cetylpyridinium chloride (CPC) to a nonionic, non‐surface active macromolecule, polyethylene glycol 20 M (PEG), has been investigated by equilibrium dialysis and a microbiological viable count technique. The results indicate that the bactericidal activity of CPC in aqueous solutions of the PEG cannot be simply equated with the activity of free aqueous CPC. The activity was found to be equal to or greater than that expected from the binding data depending on the CPC concentration. The implications of the experimental findings are discussed.
Comparison of Plating and Most Probable Number Techniques for the Isolation of Staphylococci from Foods
Authors: Patterson J. T. 
Published: March 2008

ABSTRACT.The recovery of Staphylococcus aureus on a solid medium similar to that of Smith & Baird‐Parker (1964) was compared with the most probable number (MPN) of the organism in a range of foods, using the liquid medium of Giolitti & Cantoni (1966). The latter proved more efficient in detecting staphylococci in foods, particularly where low numbers were present.