bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cultural and Symbiotic Properties of Rhizobia from Egyptian Clover (Trifolium alexandrinum)
Authors: El Essawi T. M. , Abdel Ghaffar A. S. 
Published: March 2008

SUMMARYThe morphological, cultural, biochemical and symbiotic properties of rhizobial strains isolated from Egyptian clover (Trifolium alexandrinum) were compared with those of strains from Denmark, England, Czechoslovakia and U.S.A. All were microscopically similar and showed normal growth on agar slopes, in broth and in milk. Some local but none of the foreign strains grew at 35° and in 5% NaCl solution. Differences in the reduction of nitrate, fermentation of carbohydrates and utilization of organic acids were apparent. Most Egyptian clover strains improved growth of the host plant, as measured by dry weight and nitrogen content. Egyptian clover strains formed only ineffective nodules on red clover (T. pratense). In general, Egyptian clover was effectively nodulated by foreign clover rhizobia.
Biochemical and Serological Characters of Three Strains of Streptococci Previously Reported as Streptococcus crernoris Isolated from Deep‐frozen Peas after Thawing
Authors: and J. J. CAVETT , GARVIE ELLEN I. 
Published: March 2008

SUMMARYCavett, Dring & Knight (1965) identified arginine negative, group N streptococci isolahd from deep‐frozen peas after thawing as Streptococcus cremoria. Three further isolates of such organisms have been studied in detail and although having certain properties in common with Strep. cremoris, they have others which exclude them from this species and also from other species of group N streptococci so far described. The original streptococci were probably wrongly designated.
Combined Effect of Water Activity, pH and Temperature on the Growth of Clostridium botulinum from Spore and Vegetative Cell Inocula
Authors: Baird‐Parker A. C. , Freame Barbara 
Published: March 2008

SUMMARYThe initiation of vegetative growth by spores in Reinforced Clostridial Medium (RCM) adjusted to different water activities (aw) by the addition of NaCl or glycerol does not depend solely on the aw of the medium; minimum aw at which spores of Cl. botulinum types A, B and E could initiate growth were higher in the media containing NaCl. The minimum aw at which vegetative cell inocula could grow were similar to those at which spore inocula could initiate growth. The combined effect of lowering the pH and aw of the medium was to increase the minimum at which spores of types A and E could germinate and also increase the minimum at which spore and vegetative cell inocula of Cl. botulinum types A, B and E could initiate growth.
An Investigation into the Interaction between Iodine and Bacteria
Authors: Brandrick Angela M. , Newton J. M. , Henderson G. , Vickers J. A. 
Published: March 2008

SUMMARYThe interaction between aqueous solutions of radioactive iodine (131I) and washed suspensions of Escherichia coli and Staphylococcus aureus has been investigated. The conditions of the experiments were such that the bacteria were killed and no free iodine remained. Most of the iodine reacted with the bacteria by an oxidation‐reduction process, but halogenation also took place.
A Double Layered Plate Method for the Detection of Microbial Lipolysis
Authors: Alford J. A. , Steinle Elsie E. 
Published: March 2008

SUMMARYA double layered plating procedure has been adapted for the determination of lipolysis by micro‐organisms. The base layer is prepared by mixing any fat, oil or triglyceride with Victoria Blue B and agar in a blender. Layers 2–3 mm thick are poured, allowed to solidify and overlaid with a suitable nutrient medium. This procedure allows considerable flexibility in the choice of fat as well as of nutrient medium. If lipolytic counts are desired, dilutions can be placed on the surface of the base layer prior to pouring the nutrient medium. Data are presented to show that no single fat or nutrient medium is suitable for all micro‐organisms. Acid production from carbohydrates in the medium rarely caused confusion in recognizing lipolysis.
Relationship between Carbon Dioxide Production and Growth of Pure Strains of Bacteria on Porcine Muscle
Authors: Gardner G. A. , Carson A. W. 
Published: March 2008

SUMMARYThe growth of a Pseudomonas sp., an Enterobacter sp., Kurthia zopfii, Microbacterium thermosphactum and a Lactobacillus sp. in pure culture on porcine muscle at 16 and 2° was examined in both open and gas‐tight systems. The CO2 in the headspace of the gas‐tight containers was produced by the muscle and by the bacteria. The Gram negative bacteria produced much lower amounts of CO2 than the Gram positive organisms. Data on the effects of CO2 on the growth of each bacterium at 16 and 2° are presented.
Psychrophilic Spoilage Bacteria of Fish
Authors: Shaw B. G. , Shewan J. M. 
Published: March 2008

SUMMARYSterile press juice from raw muscle of cod and ethylene oxide — sterilized cod muscle blocks were used to determine the spoilage potential of representative bacterial species present on cod, and to ascertain the incidence of spoilers on whole gutted fish during storage in ice. Growth and spoilage rates of selected cultures were studied between — 6° and +6°. A high proportion of Pseudomonas spp. spoil fish at 0.6° particularly members of groups II, III, and IV. The proportion of active spoilers of the total viable population on fish does not alter markedly during spoilage and remains below 25%. Growth of and spoilage by single Pseudomonas spp. is evident at — 3° even after a period of about 3 weeks.
Psychrophilic Spoilage Bacteria of Poultry
Authors: Barnes Ella M. , Impey C. S. 
Published: March 2008

SUMMARYThe organisms most commonly found growing on poultry carcases stored at 1° are pigmented and nonpigmented strains of Pseudomonas, Pseudomonas putrefaciens and strains of Acinetobacter. A comparison of total viable counts at 20 and 30° using stored turkeys, showed that certain strains could not be recovered at the higher temperature. When inoculated into minced breast and leg muscle, it was found that the pigmented and nonpigmented strains of Pseudomonas grew well in both muscle tissues. Strains of Acinetobacter groups B and C failed to grow in the breast muscle but grew in the leg muscle, Acinetobacter C growing much more rapidly than Acinetobacter B. The growth of Ps. putrefaciens was much faster in the leg muscle than in the breast muscle. These differences could partially be explained by differences in pH, the breast muscle having a pH value 5.7—5.9 compared with a pH value 6.4—6.7 for the leg muscle. The possible significance of these results in relation to the distribution and growth of these organisms on the chicken or turkey carcase is discussed.
Two Improved Media for Isolating and Enumerating Enterococci in Certain Frozen Foods
Authors: Lachica R. V. F. , Hartman P. A. 
Published: March 2008

SUMMARYA direct plating method was employed in a comparison of two newly modified selective media, Tween‐carbonate (TC) and thallous acetate‐citrate (TAC) agars, and 4 other selective media, M‐enterococcus (ME) thallous acetate (TA), KF‐streptococcus (KF) and citrate‐azide (CA) agars, for enumerating enterococci in some frozen foods. Pure cultures of enterococci yielded comparable counts on TC, TAC, TA, KF and CA agars. When frozen food samples were plated, enterococcal counts on TA agar were generally higher than counts obtained on TAC, ME, TA or KF agars; TC and TAC agars were more selective than the other media tested. The TC agar at pH 6 inhibited enterococcal growth in the absence of bicarbonate. TC and TAC agars were the most suitable for isolating the interococci both qualitatively and quantitatively.
Evaluation of Methods Used in Counting Azotobacters
Authors: Abd‐el‐Malek Y. , Ishac Y. Z. 
Published: March 2008

SUMMARYThe common methods of counting Azotobacter spp. in soil, colony counts and MPN, were compared using cell suspensions of densities determined by direct microscopic counts. A highly significant positive correlation was found between the surface‐plate, MPN and total cell counts, but the MPN estimations approximated total cell counts much more closely. Inclusion of 1‐1.5 g of agar/l of the liquid medium enhanced multiplication of azotobacters and facilitated the recording of growth in MPN estimations.
Distribution of Psychrophilic Micro‐organisms in Different Dairy Environments
Authors: Dempster J. F. 
Published: March 2008

SUMMARY421 cultures of psychrophilic bacteria, yeasts and moulds obtained from 8 sources were characterized to genus and species level by standard tests. 43% were Pseudomonas spp., 20%Achromobacter spp., 11.6% coli‐aerogenes bacteria and 10.2% flavobacteria. The remaining cultures were classified as Paracolon and Aeromonas spp., coryneform bacteria, micrococci, yeasts and moulds. 339 isolates were tested for lipolytic activity on tributyrin and butter fat agars. Results indicated that 232 (68.5%) and 215 (63.3%) were lipolytic on tributyrin and butter fat respectively.
Microbiological Sampling of Surfaces
Authors: Favero M. S. , McDade J. J. , Robertsen J. A. , Hoffman R. K. , Edwards R. W. 
Published: March 2008

SUMMARYThis report summarizes the 4 basic methods for the microbiological sampling of surfaces. Whereas no single assay procedure can characterize completely the microbial elements on a surface, the rinse technique is probably the most accurate for enumerating viable micro‐organisms, and the direct surface agar plating technique is the best for enumerating particulates containing viable micro‐organisms. However, the convenience of other methods, such as the agar contact method, will often be the dominant factor in the selection of a sampling method.
A Note on the Vitamin Requirements of Some Coryneform Bacteria from Soil and Herbage
Authors: Owens J. D. , Keddie R. M. 
Published: March 2008

SUMMARYThe nutritional requirements of 12 strains of coryneform bacteria were examined. Specific vitamin requirements were determined for 7 strains but the remaining 5 strains did not grow in any of the defined media used. Four strains showed vitamin requirement patterns which have not previously been reported for coryneform bacteria. These patterns were biotin + pyridoxal; thiamine + pyridoxal; thiamine + riboflavin + vitamin B12 (stimulatory); and biotin + thiamine + pantothenate + riboflavin.
Use of Germ‐free Mice for Testing Human Isolation Systems
Authors: Barnes R. D. , Holliday Jean , Cook R. 
Published: March 2008

SUMMARYGerm‐free mice were introduced to test the efficiency and use of a human isolator designed to prevent the entry of viable bacteria. The mice remained free from bacterial contamination for the total period of 7 days spent in the isolator. The use of germ‐free mice for testing systems of contamination control is discussed.
A Microbiological Survey of British Fresh Sausage
Authors: Dowdell Marilyn J. , Board R. G. 
Published: March 2008

SUMMARYThis survey indicated that British fresh sausages contain 1‐5000 × 105 viable organisms/g, with Microbacterium thermosphactum predominant in the majority of samples. With lightly contaminated sausages, yeasts were abundant. They made a meagre contribution, however, in samples containing >1.0 × 107 organisms/g. In such material, members of the Pseudomonas–Achromobacter complex tended to be plentiful. Coliaerogenes organisms were recovered from the majority of samples, their numbers ranged from 1.3 to 2400 × 102/g. A similar situation obtained with Group D streptococci. Little change in the size of the microbial populations occurred during brief periods of storage but there was evidence of change in the composition of the flora. Fermentative organisms such as microbacteria and yeasts developed at the expense of the aerobic Gram negative organisms. Lactic acid bacteria made only a small contribution to the initial populations of sausages and their number did not increase appreciably when the commodity was held overnight under refrigeration or at room temperature.
Survival of Heated Streptococcus faecalis as Affected by Phase of Growth and Incubation Temperature after Thermal Exposure
Authors: Beuchat L. R. , Lechowich R. V. 
Published: March 2008

SUMMARYEffects of the growth phase of 3 Streptococcus faecalis strains on heat resistance at 60° was studied. During the initial and middle logarithmic growth phases no resistance to 60° was found. Organisms heated in a stationary phase of growth were incubated at temperatures ranging from 45 to 7.3° to determine the effect of incubation temperature on their survival. Maximum survival of heated organisms was observed at optimum growth temperatures of c. 30°. The incubation time required for maximum recovery was longer for heated than for unheated organisms, regardless of the incubation temperature.
Comparison of the Action of Vantocil, Cetrimide and Chlorhexidine on Escherichia coli and its Spheroplasts and the Protoplasts of Gram Positive Bacteria
Authors: Davies A. , Bentley Muriel , Field Barbara S. 
Published: March 2008

SUMMARYThe actions of chlorhexidine, cetrimide and Vantocil (the hydrochloride of a polymeric biguanide) on bacteria and spheroplasts or protoplasts derived therefrom have been compared. Lysis of Escherichia coli spheroplasts by chlorhexidine or cetrimide is due to rupture of the cytoplasmic membrane. Membranes ruptured with cetrimide can reform to give small, empty envelopes. With increasing concentrations of cetrimide or chlorhexidine more and more granules appear in the cytoplasm, increasing in size with increasing concentration, until the structure becomes transformed to a granular body similar in size to the original spheroplast. With chlorhexidine or Vantocil this now electron‐dense body is rigid, but with cetrimide it collapses to a flat disc which does not lyse. The granules appear to consist of coagulated cytoplasm. This effect of excess of these antiseptics not only prevents osmotic lysis of the spheroplast or the collapsed disc but renders them immune to lysis by a variety of chemical agents. In isolated cytoplasm, chlorhexidine or cetrimide causes precipitation over a narrow range of concentrations but greater than those required for lysis. With Vantocil precipitation occurs gradually over a wide range of concentrations, starting at concentrations equal to those which cause a limited amount of lysis of the spheroplast or a relatively small increase in permeability of intact bacteria. Lanthanous and uranyl ions also precipitate cell contents but do not lyse spheroplasts; spheroplasts treated with these ions are protected from lysis by other agents.
Studies Arising from Observations of Osmophilic Yeasts by Phase Contrast Microscopy
Authors: Scarr M. Pamela 
Published: March 2008

SUMMARYOsmophilic yeasts growing in concentrated sugar solutions vary in cell density with age and activity. Microscopic observations with phase contrast by Barer & Joseph's (1958) technique have confirmed this with all strains examined. Examination of syrups containing a culture of Saccharomyces rouxii indicates that growth is limited to these high concentrations owing to the physiological dryness of the habitat. However, some growth does take place, even in the film of molasses surrounding the sucrose crystal in stored raw sugar.At c. 60% (w/w) of dissolved solids it is possible to identify active cells microscopically. Therefore the examination of raw sugar consignments for such cells is a rapid way of indicating whether the sugar is likely to deteriorate on storage.
Some Modifications to Dawson's Continuous Cyclone Column Culture Apparatus
Authors: Carr J. G. , Skerrett E. J. , Tucknott O. G. 
Published: March 2008

SummaryAlternatives to Dawson's pneumatic levelling device have been devised so that the machine can be operated without loss of volatile substances from substrate or end product. The cyclone column has been modified by adding a side arm on which is fixed a level sensing device. Two methods for sensing the liquid level are described. The first is a light‐beam/phototransistor system actuated by the rise and fall of a float; the second is a device capable of sensing a change in capacitance caused by movement of the liquid towards or away from a sensing probe. Either of these systems can be linked to a pump controlling the inflow of fresh medium. The manufacture of Fino sherry was chosen as an example of a process with a volatile substrate and end product because it involves the partial oxidation of ethanol to acetaldehyde by a Flor yeast.
Isolation and Identification of Clostridia from North Sea Sediments
Authors: Davies June A. 
Published: March 2008

SummaryUsing enrichment techniques, it was possible to isolate clostridia from marine sediments collected from 10 stations in the North Sea. Of the total number of isolates Clostridium bifermentans constituted 47% and Cl. welchii 21%, while Cl. sordellii constituted 18%. The remainder were unknown species. Evidence of cellulolysis was obtained, but no organism has as yet been isolated. No psychrophilic anaerobes were found.
The Performance of a Stable Version of Baird‐Parker's Medium for Isolating Staphylococcus aureus
Authors: Holbrook R. , Anderson Judy M. , Baird‐Parker A. C. 
Published: March 2008

SummaryA stable version of Baird‐Parker's medium has been devised by modifying the method of preparation. Poured plates of the medium can be stored for up to 28 days at 4° without any loss of selectivity. Its performance is compared with the original Baird‐Parker's medium and 2 commercial formulations.
The Use of Serratia indica and Bacillus subtilis var. niger Spores for Tracing Sewage Dispersion in the Sea
Authors: Pike E. B. , Bufton A. W. J. , Gould D. J. 
Published: March 2008

SummaryExperiments were conducted at 2 coastal sites to evaluate the suitability of Serratia indica and spores of Bacillus subtilis var. niger for tracing offshore and longshore dispersion of sewage released from submarine outfalls. Neither organism was found in the sea or the rivers studied prior to an experimental release and, whereas tracer spores persisted in the sea and the littoral zone for some days after release, S. indica disappeared within a few days. Where S. indica was released continuously from an outfall, it dispersed similarly to coli‐aerogenes bacteria. Both tracers were killed rapidly in seawater exposed to sunlight, but their mortality kinetics differed. Tracer spores did not die or germinate in the dark when suspended in sewage during 24 h or in seawater during 9 days, but death occured after 3 days in seawater exposed to sunlight. Spores dispersed offshore similarly to K82Br and to S. indica; because of this and their stability, it was thought that they could be used for measuring physical dilution independently of mortality. The continuous release of S. indica into the sea is suitable for measuring the pollution field around a discharge; adding single doses of either tracer yields information on dispersion processes and transit times to the shore.
Action of Biguanides, Phenols and Detergents on Escherichia coli and its Spheroplasts
Authors: Davies A. , Field Barbara S. 
Published: March 2008

SummaryThe bactericidal potency of groups of biguanides, phenols and detergents has been compared with that of the bis‐biguanide, chlorhexidine, and related to measurable effects of the compounds on bacteria. Biguanides, like chlorhexidine, precipitated bacterial cytoplasm and also lysed spheroplasts over a limited concentration range: higher concentrations prevented lysis. Certain phenols and detergents which lysed spheroplasts did not precipitate cytoplasm. All the compounds released radioactivity from isotopically labelled bacteria; at suitable concentrations, biguanides released more radioactivity than chlorhexidine, but at higher concentrations the amount of radioactivity released was reduced. Bactericidal activity correlated with both the ability to lyse spheroplasts and to precipitate cytoplasm from solution. The findings support the hypothesis that damage to the cell wall alone does not kill bacteria but an increase in permeability allows entry of the bactericide. Action of compounds on the cell wall is discussed in relation to a model of its ultrastructure.
A New Multiple Inoculator for Bacteriocine Typing
Authors: Merrikin D. J. , Terry C. S. 
Published: March 2008

SummaryA new design of multiple inoculator for bacteriocine typing is described. The inoculator consists of a ridged aluminium roller and is used in conjunction with an aluminium inoculum tray. The inoculator permits more certain sterilization than previous designs, which are briefly reviewed.
Studies on the Mode of Action of Some Cephalosporin Derivatives
Authors: Fountain R. H. , Russell A. D. 
Published: March 2008

Summary7‐(s‐benzylthioacetamido)‐cephem‐3‐ylmethyl‐N‐dimethyldithiocarbamate‐4‐carboxylic acid (cephalosporin 7/30) prevented benzylpenicillin from inducing spheroplasts in Escherichia coli, and inhibited growth of preformed spheroplasts. These effects were also noted with dimethyldithiocarbamate (DMDT), the side‐chain at position 3 in 7/30. Cephalosporin 7/30 inhibited growth of protoplasts of Bacillus megaterium and Streptococcus faecalis. At high concentrations, 7‐[(2‐thienyl)acetamido]‐cephem‐3‐ylmethyl‐N‐dimethyldithiocarbamate‐ 4‐carboxylic acid (cephalosporin 87/30), with the same side‐chain at 7 as cephaloridine but with DMDT at position 3, prevented spheroplast formation in E. coli, and inhibited the growth of preformed spheroplasts. However, at lower concentrations, 87/30 induced spherical forms in E. coli. The other cephalosporins, tested induced spheroplasts in E. coli and had no effect on protoplasts.
The Nitrogen Nutrition of Soil and Herbage Coryneform Bacteria
Authors: Owens J. D. , Keddie R. M. 
Published: March 2008

SummaryThe nitrogen nutrition of 93 strains of soil and herbage coryneform bacteria and 16 named strains of Arthrobacter and Cellulomonas was examined. In testing for the ability of coryneform bacteria to utilize inorganic nitrogen as sole nitrogen source it was found necessary to use a medium containing a balanced mineral base and a suitable metal chelating agent in order to obtain reproducible results. A suitable medium is described. When provided with essential vitamins, 90% of soil isolates utilized inorganic nitrogen as sole nitrogen source while only 30% of herbage isolates did so. Sixty per cent of herbage isolates utilized inorganic nitrogen as major nitrogen source when provided with l‐methionine in addition to vitamins, whereas no soil isolate showed a requirement for methionine. For a small residue of strains from each habitat the substrate nitrogen requirements were not determined. Of the named strains examined A. terregens utilized inorganic nitrogen as major nitrogen source when provided with methionine and vitamins while the remainder utilized inorganic nitrogen as sole nitrogen source. For 4 Arthrobacter spp. the nitrogen requirements described differ from those previously reported.
A Selective Medium for the Isolation of Agrobacterium Species
Authors: Clark A. G. 
Published: March 2008

SummaryA defined salts medium containing lactose and MnSO4 as selective agents is described. This medium inhibits nearly all organisms of the soil microflora except Agrobacterium spp. against which it has no repressive or mutagenic effect. By using a modified test for 3‐ketolactose production together with plant inoculation, qualitative and quantitative assays for agrobacteria are possible.