bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors Controlling the Sporulation of Yeasts II. The Sporulation Phase
Authors: Fowell R. R.
Published: March 2008

The degree of sporulation exhibited by yeasts was greatly influenced by cell population density (CPD). In general, optimal sporulation occurred over a narrow range of low CPD values for solid and liquid media. On acetate agar, however, optimal sporulation was obtainable over a wide range of CPD values above a certain, usually low, threshold. There is evidence that on this medium, the effect of CPD is due to a small but critical requirement of CO2 for sporulation. Addition of potassium improved sporulation in the presence of acetate and pyruvate, but there was little effect with glucose. Nitrogen compounds and yeast extract tended to delay and depress sporulation in the presence of acetate. Most yeasts sporulated best on acetate agar at pH 8.4‐10.6 irrespective of CPD; a high pH was also necessary for optimal sporulation on glucose agar, but its value depended on glucose concentration and CPD. Buffering of pyruvate and glucose agar was necessary for the best results, but it was not usually needed for acetate media, the pH of which rose rapidly after inoculation to the optimal range. Glucose, pyruvate and, in particular, acetate, all proved capable in general of inducing a higher degree of sporulation than was possible, under the best conditions, in their absence.
Comparative Trials of Seed Pelleting, Inoculation and the Use of High Lime Dressings in Upland Reclamation
Authors: Jones D. Gareth , Druce R. G. , Williams G.
Published: March 2008

At 3 centres in North, South and Central Wales, respectively, trials were made to compare the establishment and growth of white clover using seed pelleted with lime or with lime + Gafsa phosphate on unlimed soil, and non‐pelleted seed on limed or unlimed (control) soils. All treatments were divided into inoculated and uninoculated sections using an effective strain of Rhizobium trifolii. There were significant differences in clover establishment between the unlimed control plots and those that received 3 tons of ground limestone/acre but no overall significant effect of inoculation. The no. of nodules/plant was increased significantly both by high lime applications and by lime pelleting with inoculation. Both high lime and lime pelleting gave higher clover contents of the sward, and the total increase in clover due to inoculation was also highly significant. While the percentage clover in the sward derived from pelleted seed is low compared with that in the high lime plots it is considered that the use of inoculated pelleted seed is a cheaper and easier method of upland reclamation than applying heavy dressings of lime.
Hot Air Sterilization at 200°
Authors: Quesnel L. B. , Hayward Janet M. , Babnett J. W.
Published: March 2008

The efficiency of an automatic dry heat instrument sterilizer was tested using as test inoculum a mixture of spores of Bacillus subtilis strain MD2 and B. subtilis var. niger as air dried films on stainless steel and glass objects. The sterilizer was operated at 200° and was found to be capable of sterilizing 20 stainless steel strips weighing 4 g each in an overall cycle time of c. 20 min; 6 sputum cups of total weight c. 2 kg required c. 38 min. Glass jars of equivalent weight appeared to need a longer time than did steel mugs. The factors involved in dry heat sterilization are discussed.
A Note on Steam Sterilization of Spore Films on Inaccessible Surfaces
Authors: Quesnel L. B.
Published: March 2008

Simple experiments with inoculated stainless steel strips demonstrate the difficulty of sterilizing by steam when the spore films are on inaccessible surfaces.
Enzymes of Thermophilic Aerobic Sporeforming Bacteria
Authors: Baillie Ann , Walker P. D.
Published: March 2008

Esterase patterns of 217 strains of thermophilic aerobic sporeforming bacteria were examined by starch gel electrophoresis. Classification of these strains by this method corresponded closely with the results obtained by biochemical tests. Protein patterns were also examined by acrylamide gel electrophoresis. In order to study the heat resistance and other properties of the esterases, an attempt was made to purify them using high voltage carrier‐free electrophoresis.
Clostridium botulinum type E: Growth and Toxin Production in Food
Authors: Ajmal M.
Published: March 2008

Growth and toxin production by Clostridium botulinum type E in experimentally inoculated irradiated and unirradiated horsemeat and fish (herring and cod), and cured meats, was investigated. No OS or TP variant was observed during growth. Toxin was produced under both aerobic and anaerobic conditions of incubation. Irradiated fish was found to be more susceptible to toxin production than unirradiated fish similarly treated. Toxic outgrowth occurred in two products of ham and one of cured ox tongue with concentrations of NaCl < 3.7% and nitrite < 3 p/m. Corned beef containing 4.6% of NaCl and 60 p of nitrite/m did not allow the growth of type E with an inoculum as large as 1 × 105 spores/g.
Heat and Radiation Resistance and Activation of Spores of Clostridium welchii
Authors: Roberts T. A.
Published: March 2008

Spores of‘classical’strains of Clostridium welchii were more sensitive to heat (D90° 3–5 min) than spores of‘food poisoning’strains (D90° 15–145 min) from the same sporulation media. The z values of‘classical’strains (z=11–14°F) were lower than for‘food poisoning’strains (z= 16–29°F). 30–50% of spores of‘classical’strains grew without heating, and no heat activation was detected. Only 0.13‐3.6% of spores of‘food poisoning’strains grew without heating, heat activation being generally detected at 75–80°, and on one occasion at 75–100°. Spores of‘food poisoning’strains were more resistant to γ radiation (D=0.26‐0.34 Mrad) than spores of‘classical’strains (D=0.12‐0.21 Mrad).
Brucella abortus in Milk Supplied to Glasgow
Authors: Tadayon R. A.
Published: March 2008

One hundred and twentyeight bulk milk samples from 114 farms producing certified milk, 78 bulk raw and 50 pasteurized milk samples from 27 pasteurizing plants, 73 samples of milk from individual aborting animals and 51 individual samples of certified milk were examined for the presence of Brucella spp. Of the samples in these groups 18 (15.8%), 8 (10.3%), 28 (50.0%) and 5 (9.8%) respectively, contained Br. abortus. Fortyeight cultures of brucella were typed. Four cultures behaved like Br. melitensis and the remaining 44 resembled Br. abortus. Of the Br. abortus, 41 belonged to type 1 and the remaining 3 to type 2.
Mechanism of Enhancement of Lactic Acid Fermentation of Green Olives by Alkali and Heat Treatments
Authors: Juven B. , Samish Zdenka , Henis Y. , Jacoby B.
Published: March 2008

The marked enhancement of lactic fermentation rates of intact Merhavia and Manzanillo green olives in brine following pretreatment with hot alkali results mainly from the destruction of an antilactic factor by the alkali. The press juice of Manzanillo green olives contains an ether‐extractable, hot alkali labile factor which temporarily inhibits acid production by Lactobacillus plantarum in APT broth. A rapid method for the detection of the antilactic factor is described. The antilactic factor present in intact green olives may not be the same as that in the press juice.
Toxic Subunits of the Crystal of Bacillus thuringiensis
Authors: Pendleton I. R.
Published: March 2008

Products of digestion of the protoxin crystals of Bacillus thuringiensis var. berliner by gut juice of larvae of Pieris brassicae were examined by gel filtration, antigenic analysis, electrophoresis and toxicity tests. The digest was separated into 2 fractions; fraction 1 contained a protein of molecular weight > 200,000, and fraction 2 contained a peptide with a molecular weight between 5000 and 10,000. Only fraction 2 was toxic to the insect larvae on injection although both fractions were toxic by feeding. The association of toxicity of fraction 2 with certain antigens is described and a possible relationship between the two fractions is discussed.
Deoxyribonucleic Acid Base Composition of some Marine and Halophilic Micrococci
Authors: Bohaaček J. , Kocur M. , Martinec T.
Published: March 2008

The guanine + cytosine (GC) content of the DNA's of 15 strains of marine and halophilic micrococci was determined using the methods of Marmur & Doty (1962) and Frédéricq, Oth & Fontaine (1961), and by paper chromatography. Only 4 strains having 69.3‐72.8% of GC could be considered as members of the genus Micrococcus. Four motile cocci had GC contents of c. 41%: these should be placed in the genus Planococcus. Two strains by their GC contents of 32‐33% belong to the genus Staphylococcus. The GC content of the DNA of the strains of Micrococous morrhuae ranges from 57.1 to 61%.
Fatty Acids of Rhodotorula gracilis: Fat Production in Submerged Culture and the Particular Effect of pH Value
Authors: Kessell R. H. J.
Published: March 2008

Rhodotorula gracilis growing in batch culture exhibited acceleration, exponential and linear phases of growth. In a fourth phase, following nitrogen exhaustion, the concentration of lipid in the culture increased, but it is suggested that the rate of lipid production was not stimulated but remained constant, the apparent increase being almost entirely due to the absence of cell proliferation. No significant changes occurred in the fatty acid composition of the lipid when nitrogen was exhausted. At low pH values, growth of the organism was retarded, but the lipid production rate increased although the final concentration of lipid remained the same. The ratio of unsaturated to saturated fatty acids also decreased principally due to a lowered concentration of oleic acid but the concentration of myristic, stearic, linoleic and linolenic acids increased.
An Improved Method for Determining Cellulolytic Activity in Anaerobic Bacteria
Authors: Mann S. O.
Published: March 2008

An improved method for determining cellulolytic activity in anaerobic bacteria is described in which the disintegration of a filter paper strip denotes activity. By inoculating the paper‐containing media from dilutions of material such as rumen contents estimates of the numbers of cellulolytic bacteria in the original material may be made. The method can also be used for determining cellulolytic activity of pure cultures. Morphology and other properties of the bacteria may be determined.
Enumeration of Staphylococcus aureus in Foods with Special Reference to Egg‐yolk Reaction and Mannitol Negative Mutants
Authors: Waart J. De , Mossel D. A. A. , Broeke R. ten , Moosdijk A. van de
Published: March 2008

Chapman's medium designed for the enumeration of Staphylococcus aureus showed three shortcomings: (i) micrococci and many Bacillus spp. grow well on this agar and may obscure colonies of Staph. aureus; (ii) some strains of Staph. aureus fail to dissimilate mannitol; among 1164 strains examined, mostly from clinical sources, 4.4 % appeared unable to dissimilate mannitol; (iii) the agar has inhibitory properties to sublethally impaired cells of Staph. aureus. The latter deficiency not being correctable, the suitability of the egg yolk‐tellurite‐glycine‐pyruvate agar (ETGPA) of Baird‐Parker (1962b) was evaluated. Of 522 strains of Staph. aureus of human and food origin 97.5 % developed characteristically and generally quantitatively on Baird‐Parker's agar.

Baird‐Parker's medium has proved valuable in ecological studies on the occurrence and development of Staph. aureus in foods incriminated in staphyloenterotoxicosis: among 165 atypical black colonies isolated from 450 food samples only 2% were Staph. aureus.
Esterases and DNA Base Composition Analysis of Vibrio cholerae and Related Vibrios
Authors: Colwell R. R. , Adeyemo V. I. , Kirtland H. H.
Published: March 2008

Esterases of strains of Vibrio cholerae, V. parahaemolyticus, noncholera and marine vibrios were examined by electrophoresis in starch gels. The enzyme patterns indicated a relative homogeneity occurring amongst the strains. No separation of the genus Vibrio into subgroups corresponding to the El Tor, classical cholera or noncholera groupings was noted. Overall deoxyribonucleic acid base composition for the Vibrio spp. ranged from 44‐49 mol% guanine + cytosine, with the marine vibrios lowest in guanine + cytosine content. Enzyme patterns for cholera vibrios isolated during very recent epidemics were identical to those of established laboratory strains, suggesting a marked stability of the esterase system for V. cholerae.
Salt Tolerance in Pigmented and Nonpigmented Strains of Bacillus Species Isolated from Soil
Authors: Turner Myfanwy , Jervis D. I.
Published: March 2008

Different methods of estimating growth were used for comparing the salt tolerance of pigmented and nonpigmented strains of Bacillus species isolated from soils. The pigmented strains tolerated much higher concentrations of NaCl than the nonpigmented strains from the same sources.
Nitrogen, Energy and Vitamin Nutrition of Rhizobium japonicum
Authors: Elkan G. H. , Kwik Iem
Published: March 2008

The energy, nitrogen and vitamin nutrition of 36 strains of Rhizobium japonicum were investigated. Most of the strains utilized gluconate, glycerol, arabinose, glucose, mannose, mannitol, sorbitol, galactose and maltose. Pyruvate, succinate, ribose, ribitol, xylose, fructose and lactose were of limited use whereas acetate, propionate, lactate, malate, citrate and sucrose were uniformly inadequate as carbon or energy sources. All strains grew well with vitamin‐free casein hydrolysate, and 6 could utilize ammonia as sole nitrogen source. Glutamate was utilized by 33 strains, histidine by 26, aspartate by 20 and proline by 26 strains. Other amino acids were not utilized by most strains. The organisms grew independently of any vitamins except biotin. Three of the strains were stimulated and growth of 4 was inhibited by biotin.
Taxonomy of some Staphylococci and Micrococci Isolated from Bovine Teat Canals and Foremilks
Authors: Forbes D.
Published: March 2008

The taxonomy of 2404 cultures of Gram positive, catalase positive, nonmotile cocci was determined using Baird‐Parker's (1963) classification. The bacteria were isolated from bovine teat canals and milk samples during 2 lactations of an experimental herd of cattle and their taxonomic positions were assessed on the basis of 8 reactions. Most were clearly assigned to typical subgroups, although some arabinose positive staphylococci and VP positive and phosphatase positive micrococci were atypical. Cultures representative of these and typical subgroups were examined in more detail using 25 reactions. Most cultures were again classified as being typical but it was shown that the atypical cultures were genuinely different from bacteria examined by Baird‐Parker. A marked difference was found in the results of the phosphatase reaction on Baird‐Parker's phosphatase medium and on that prepared with a different base used in this work. The atypical micrococci gave a negative result when tested on Baird‐Parker's medium but their carbohydrate reactions still differentiated them from other subgroups.

Carbohydrate oxidation tests varied in intensity depending on whether the medium was prepared as slopes or plates. The slopes gave a more intense reaction which persisted once a positive reaction occurred. The methods used provide additional means for epidemiological studies of Micrococcaceae in dairy herds.
Effects of Pasteurization or Added Sulphite on the Microbiology of Stored Vacuum Packed Baconburgers
Authors: Gardner G. A.
Published: March 2008

The flora of untreated vacuum packed baconburgers which were allowed to spoil at 5, 10 and 22° was dominated by atypical streptobacteria. Corynebacterium spp., micrococci, Bacillus spp. and lactic acid bacteria survived the post‐packing pasteurization treatments. There was no increase in bacterial numbers in 3 weeks at 5°, but at 10 and 22° group D streptococci grew and caused a souring spoilage of the product. Sodium metabisulphite, added to an initial level of 300 p/m SO2 retarded the growth of organisms, but had no qualitative effect on the flora. Of the two methods for extending the shelf life of vacuum packed baconburgers, the addition of SO2 was the safer, as the public health significance of group D streptococci is at present decidedly equivocal.
Anaerobic Gram Negative Nonsporing Bacteria from the Caeca of Poultry
Authors: Barnes Ella M. , Impey C. S.
Published: March 2008

Four groups (1, 4, 5 and 6) of Gram negative, nonsporing anaerobic rods (family Bacteroidaceae) which have been isolated from the caeca of chickens, turkeys and ducks, are described. Two of the groups (1 and 6) belong to the genus Sphaerophorus but differ in a number of characteristics from named strains. The group 5 strains belong within the genus Bacteroides and resemble Bact. fragilis. The group 4 strains differ from Sphaerophorus and Bacteroides and have not yet been assigned to a genus. The methods used for isolating and identifying these organisms are discussed.
A Note on the Production of Radioactive Sulphide by Desulfovibrio desulfuricans
Authors: Jones‐Mortimer M. C.
Published: March 2008

A method was developed for the preparation of [35S] cadmium sulphide from [35S] sodium sulphate employing cultures of Desulfovibrio desulfuricans. [35S] H2S may be prepared by the action of 2 N hydrochloric acid on [35S] cadmium sulphide.
Neomycin‐containing Media in the Isolation of Clostridium botulinum and Food Poisoning Strains of Clostridium welchii
Authors: Spencer R.
Published: March 2008

Many strains of Clostridium botulinum types A and B and nonhaemolytic food poisoning strains of Cl. welchii were inhibited by 200 μg, but in general not by 50 μg, of neomycin/ml in blood agar or Nagler agar. Cl. botulinum type E was particularly sensitive to neomycin, growth being prevented by a concentration of 25 μg/ml of medium.
Gravimetrical and Mycological Investigations of Soil Suspensions in the Soil Dilution Plate Technique
Authors: Hornby D.
Published: March 2008

Certain common methods used for agitating and sampling soil suspensions in the dilution plate method were tested gravimetrically for accuracy and precision and compared mycologically on the basis of colony counts. No method could be relied upon for gravimetrically representative samples and in general methods with high precision were very biased and those with low bias were very variable. Some methods, such as magnetic stirring of soil in a viscous diluent, were better overall methods on the gravimetric criterion. Pipette samples underestimated and dipper samples overestimated the weight of soil in the primary suspension. Continuous agitation during sampling was essential for the highest colony counts and permitting settling for 4–5 min significantly decreased counts. Viscous diluents and other minor refinements were not significant improvements mycologically. In a comparison between a positively biased sampling method and a negatively biased one, transferring only one quarter as much soil from the primary soil suspension, no significant difference in colony counts occurred. The possible interpretations of this are discussed.
Methods of Assessing the Psychrotrophic Bacterial Content of Milk
Authors: Thomas S. B.
Published: March 2008

The various methods used for the determination of the psychrotrophic bacterial content of refrigerated milk are reviewed and assessed. A standard reference method, involving incubation of poured plates at 7° for 10 days, is recommended for the determination of psychrotrophic colony counts for investigational purposes. Many ingenious techniques, based on media selective for Gram negative bacteria, with incubation at higher temperatures and shorter times are described and appraised. A simple procedure which would provide a more rapid assessment of the number of active milk spoilage types of psychrotrophs is needed for routine purposes, and it is suggested that the enumeration of microcolonies by the drop plate or membrane filter methods with incubation at 7° for 72 h would provide a suitable technique for this purpose.

Incubation of plates at 25° for 5 days is recommended as a standard reference method for determining the total colony count of bacteria in refrigerated milk, but for routine purposes where large numbers of milk samples are being examined incubation at 28–30° for 3–4 days would provide a sound enough estimate.
Sterilization by Radiofrequency Induction Heating: a Method for the in situ Sterilization of Vessels in Automatic Bacteriological Apparatus
Authors: Trotman R. E.
Published: March 2008

A stainless steel pipette and a stainless steel wire were heat sterilized, in 8 and 4 sec, respectively, by radiofrequency induction. The method seems suitable for sterilizing vessels in situ and for general purpose sterilization.
Growth and Sporulation of Clostridium welchii in Breast and Leg Muscle of Poultry
Authors: Mead G. C.
Published: March 2008

Growth of a heat resistant, food poisoning strain of Clostridium welchii was followed in raw, minced breast and leg muscle of the chicken. Within the range 22–50° growth was slightly more rapid in the leg (pH 6·5–6·7) than in the breast (pH 5·6–5·7) and was fastest in leg muscle at 50°. No growth occurred at 15 or 52°.

In a comparison between chicken and turkey, inoculated breast and leg muscle were cooked for 1 h at 85° and held at 37°. Multiplication of surviving organisms was initiated much more rapidly in chicken than in turkey meat, though the growth rates were comparable in each case.

Sporulation of several strains of CI. welchii, including other heat resistant, food poisoning types, was generally 10–100 times greater in leg than in breast muscle of the chicken. Differences in sporulation could be attributed both to differences in pH and type of meat.
DNA Base Composition and Esterase Patterns of Bacteria Isolated from Deep Sea Sediments
Authors: Hogan M. A. , Colwell R. R.
Published: March 2008

Electrophoretic patterns of esterase isozymes and DNA base compositions were determined for 38 marine bacteria, 31 strains of which were from sediment samples collected at depths of 9400–10,400 in in the Philippine and Marianas Trenches of the Pacific Ocean, and 7 from seawater samples collected at various depths of surface–4000 m and from several locations in the Pacific Ocean. Previous numerical taxonomic analysis indicated 5 distinct phenetic clusters; 4 identified as Pseudomonas and 1 as aerogenic Aeromonas. In this study, the DNA base composition range for the entire sample set was found to be 41–59 moles % of GC. However, 32 of the 38 strains possessed a GC of c. 57%. In general, strains belonging to the same phenon possessed nearly identical DNA base composition and demonstrated similar esterase patterns.
Isolation and Enumeration of Aerobic Heterotrophic Bacteria in Activated Sludge
Authors: Gayford C. G. , Richards J. P.
Published: March 2008

The viable counting of bacteria in activated sludge has been investigated. The surface viable technique was considered satisfactory. The constituents of activated sludge appear to be nutritional requirements for some bacteria present. The deflocculating agents sodium pyrophosphate, sodium citrate and the nonionic surfactant, Lubrol W, facilitated the separation of bacteria from the particulate matter. A combination of sodium pyrophosphate and Lubrol W both at a concentration of 0·01% was very effective in this respect.
Further Studies on the Phage Sensitivity and the Determination of Phytopathogenic Pseudomonas spp.
Authors: Billing Eve
Published: March 2008

An interim determinative scheme for phytopathogenic Pseudomonas spp. by a variety of cultural and biochemical tests was suggested by Lelliott, Billing & Hayward (1966) following the study of 156 green fluorescent phytopathogenic pseudomonads. The phage sensitivity of these and 80 additional cultures to 20 phages from a variety of sources are described. Information on the morphology of these phages is now available (Bradley, 1963a). A few nutritional tests which seem to be of diagnostic value at the species level are also included and a relationship between the presence of a heat stable antigen (Lovrekovich et al., 1963) and phage sensitivity patterns is discussed.
A Colorimetric Bioassay Method for Colicins
Authors: Shannon R. , Hedges A. J.
Published: March 2008

A technique for the comparative assay of colicin samples is described. Relative potencies are estimated by a modification of the well known survivor count method, in which the lethal potential of samples is measured indirectly by colorimetric determination of their effect on the capacity of a sensitive indicator culture to reduce 2,3,5‐triphenyltetrazolium chloride under specified conditions. The method has (i) simplicity of operation, (ii) a wide range of application, (iii) rapidity of execution, (iv) high sensitivity, (v) good precision.
Residual Bactericidal Action of Wool Blankets Laundered with Formaldehyde: A Hospital Trial
Authors: Dickinson J. C. , Wagg R. E. , Litchfield Susan
Published: March 2008

A hospital trial of wool blankets laundered with a 0·38% (w/v) solution of formaldehyde in the last but one rinse showed evidence of residual bactericidal action of the blankets. On removal from the beds after a fortnight's use, dirty treated blankets contained down to one tenth of the number of bacteria present on dirty untreated blankets. There were also fewer dirty treated than control blankets on which coagulase positive bacteria could be detected. Chemical tests showed that the formaldehyde content of the blankets built up to c. 1%. No complaints were received of odour from the blankets.
A Comparison of Methods for Assessing the Value of Antibacterial Soaps
Authors: Wilson Patricia E.
Published: March 2008

A new antibacterial soap preparation containing trichlorocarbanilide (TCC) was compared in laboratory tests with a commercially available hexachloraphane soap and a control, nongermicidal soap. Both antibacterial soaps showed significant reductions in the skin flora, contact plate tests revealed no difference between the two preparations. In an 18 months ward trial the transmission of staphylococci was significantly reduced by the TCC soap.
A Comparator Method of Assessing Bacterial Plate Counts
Authors: Murphy R. P. , Tucker C. G.
Published: March 2008

The plate count method of assessing total viable counts of bacteria in milk, water, and foods has only a precision of ±25%, and is tedious. In the method here described plate cultures prepared in the usual way are compared visually with a series of standards: the preparation of suitable standards is discussed. By this method it is possible to assess rapidly the numbers of colonies on plates carrying up to 1000 colonies with as little as ±10% error. The speed of examination is virtually independent of the numbers of colonies present.
The Effect of Oxygen on the Germination and Outgrowth of Spores of Clostridium butyricum
Authors: Hambleton R. , Rigby G. J.
Published: March 2008

The germination of spores of Clostridium butyricum, the emergence of germ cells and replication of vegetative cells in atmospheres of different oxygen content have been quantitatively investigated by a nutrient agar slide technique. The sensitivity to oxygen of (1) the process of germination, (2) germinated spores or the process of emergence and (3) cellular replication increases progressively.
A Method for the Detection of Gelatinase Production by Bacteria
Authors: Pitt T. L. , Dey D.
Published: March 2008

A gelatin‐agar medium for the detection of gelatinase without the use of a protein precipitant is described. The development of an opacity round the colony indicates the production of gelatinase.
Aniline Utilization by Alcaligenes faecalis: A Taxonomic Reappraisal
Authors: Rhodes Muriel E.
Published: March 2008

Further studies of the aniline‐utilizing soil organism described by Walker & Harris (1969) revealed that it is not a pseudomonad, but a strain of Alcaligenes faecalis Castellani & Chambers 1919. This taxonomic correction is pertinent insofar as Pseudomonas and Alcaligenes may show different pathways of aniline degradation, and the frequency of occurrence of the two genera in the soil may be very different. One hundred and fortyone isolates of fluorescent Pseudomonas spp. from soil and water, failed to grow on aniline as sole carbon source.
Studies on the Antimicrobial Activity of Olive Phenolic Compounds
Authors: Juven B. , Henis Y.
Published: March 2008

Treatment of green olives for 2 min with dilute hot alkali before brining increased the release of sugars, B complex vitamins, amino acids and phenolic compounds, and enhanced the establishment of lactic acid bacteria in the brine. Two components of the ethyl acetate extract of green olives, which showed an antibacterial activity, were isolated and identified as the glycoside oleuropein and its phenolic aglycone. The inhibition of Lactobacillus plantarum by the ethyl acetate extract or by oleuropein was augmented by reducing the concentration of organic nitrogenous compounds, increasing the NaCl concentration in the assay medium and decreasing the inoculum size. Besides its activity towards various bacteria, oleuropein inhibited the growth of Geotrichum candidum Link, Rhizopus sp. and Rhizoctonia solani Kühn. On the basis of these findings, an explanation for some problems in the lactic fermentation of green olives is suggested.
Ultrastructure of Spore Coats Produced by Lethal Germination of Spores of Bacillus megaterium 9885
Authors: Holdom R. S. , Williams M. G. , Foster J. W.
Published: March 2008

The ultrastructure of free spore coats of Bacillus megaterium 9885 was studied by exploitation of the spontaneous lysis of newly germinated spores in the presence of phosphate and absence of Ca2+, and the subsequent release of coat subunits. The subunits appeared as the middle layer of a sandwich. The primary size of the subunits was c. 20 nm. Negative staining suggested the presence of peripheral charged groups (carboxyl?) surrounding a hexagonal‐shaped subunit containing an acentric electron opaque spot; where subunits had associated into monolayers, the peripheral rims disappeared but the number and position of subunits was located from the acentric spots which remained visible. The newly germinated cell remained attached to the spore coat via a short connecting structure of amorphous material. Ca2+ protected against lysis and also largely prevented coat disruption. Subsequent EDTA treatment did not produce the normal effects of Ca deficiency; instead, thin bridges of elastic material of apparently high tensile strength and remarkably uniform diameter were seen to connect neighbouring spore masses. The significance of these observations is discussed in relation to the known chemical composition of coats of related strains.
The Effect of Cephaloridine and a Cephalosporin Derivative on Mycoplasmas
Authors: Fallon R. J.
Published: March 2008

Cephaloridine was found to inhibit many Mycoplasma species at a concentration of 1000 μg/ml of medium. A cephalosporin derivative 7/30 was much more inhibitory than cephaloridine but was less active than dimethyldithiocarbamate, the side chain at position 3 in compound 7/30.
Agglutinin Absorption Reactions with Antigens and Antisera of Smooth Brucellae
Authors: Painter G. M. , Patterson Judy M. , Deyoe B. L.
Published: March 2008

The reactions of various Brucella antisera and Brucella antigens were investigated with agglutinin absorption techniques. Agglutinins that sedimented at the slowest rates through sucrose density gradients were absorbed preferentially, but more slowly than were fast sedimenting agglutinins. When antisera were absorbed with small defined quantities of Brucella antigens the identity of the absorbing antigen seldom influenced the results until greater than 50% of the agglutinins were removed. Consequently, the results were mainly dependent upon the antisera and assaying antigen. When antisera were absorbed with small quantities of the homologous antigen and assayed against other antigens, greater serologic differentiation of smooth Brucella was achieved than by testing with Brucella monospecific sera.
Fluorescent Pseudomonads—a Residual Component in the Soil Microflora?
Authors: Rovira A. D. , Sands D. C.
Published: March 2008

The distribution of fluorescent pseudomonads in 2 field soils was studied using a selective agar medium. The fluorescent pseudomonads were distributed unevenly through the soils, their presence being associated with particulate organic matter. Inorganic soil particles and 5 mm aggregates in one soil were devoid of fluorescent pseudomonads.

The highest number of fluorescent pseudomonads occurred on partly decomposed wheat straw in contact with wet soil. The population of fluorescent pseudomonads was less in more decomposed plant debris. Fluorescent pseudomonads made up 5·6% and 0·2% of the population of aerobic bacteria on living wheat roots and in soil shaken from the roots respectively.
The Adansonian Taxonomy of Some Cannery Flavobacteria
Authors: Byrom N. A.
Published: March 2008

Two hundred and fortyfive isolates of cannery flavobacteria and 5 reference strains were compared by 96 morphological, colonial, physiological and biochemical tests. The results were subjected to computerized Adansonian analysis to investigate the possibility that such bacteria constitute a phenetic taxon. Three pleista are postulated.
Production of Flavour‐enhancing Materials by Streptomycetes: Screening for 5′‐Nucleotides
Authors: Schwartz J. , Margalith P.
Published: March 2008

Streptomycetes were examined for their ability to accumulate flavour‐enhancing nucleotides. An efficient screening programme was devised for the isolation of streptomycetes excreting 5′‐nucleotides. Less than 0.7% of these organisms isolated from nature showed appreciable extracellular accumulation of 5′‐nucleotides, and streptomycetes derived from culture collections gave none. In shake flask experiments the yields of nucleotides were minimal and did not exceed (g/l) 0.2 of inosine 5′‐monophosphate, 0.15 of xanthosine 5′‐monophosphate, and 0.05 of guanosine 5′‐monophosphate.
Microbiological Changes in Prepacked Cod Fillets in Relation to the Oxygen Permeability of the Film
Authors: Debevere J. M. , Voets J. P.
Published: March 2008

The deterioration of prepacked cod fillets in relation to the oxygen permeability of the polyethylene film was studied bacteriologically and chemically. Spoilage at 0° is not related directly to oxygen permeability (OP). The deterioration curve at higher storage temperatures (3 and 6°) is of the same form as the curve at 0°. Moreover, from the curve it can be deduced that a film with c. 3600 ml/m2/24 h OP gives the best results. A maximum spoilage is observed with an OP c. 1800 ml/m2/24 h. Identical results were obtained with other films. The formation of formalin bound volatile nitrogen compounds is inhibited in prepacked fish whereas the trimethylamine content increases.
A Chromatographic Method for Analysis of the Gaseous Phase in Shake Flask Cultures and its Application to the Study of Methane Utilization
Authors: Molton P. M. , Pirt S. J.
Published: March 2008

A simple gas chromatograph with a katharometer detector is described to determine O2, N2, methane and CO2 in gas samples of 0·01–2·0 ml. The apparatus is inexpensive, and can be modified to determine other gases. The sensitivity to oxygen is 3 × 10−6 g. The use of the instrument is illustrated by a study of the growth kinetics of Methylococcus capsulatus grown on methane in shake flask experiments. The ratio of O2 uptake to methane uptake is much lower in the stationary phase than in the growth phase of the culture.
Studies on the Mode of Action of the Phenolic Antibacterial Agent Fentichlor against Staphylococcus aureus and Escherichia coli I. The Adsorption of Fentichlor by the Bacterial Cell and its Antibacterial Activity
Authors: Hugo W. B. , Bloomfield Sally F.
Published: March 2008

Fentichlor is adsorbed in fairly large amounts by Staphylococcus aureus and Escherichia coli and, according to the quantity adsorbed, is either bacteriostatic or bactericidal. The observed pattern of uptake, measured under various conditions, indicates that uptake involves reversible adsorption of the neutral molecule on to the cell. The drug is taken up by the cell wall and cell membrane, the latter probably being the main site of adsorption and main site of action. Although both whole cells and cell walls of E. coli have a higher affinity for Fentichlor than those of Staph. aureus, the former is less susceptible to its antibacterial action. Results indicate that this may be due to the lipid‐rich nature of the cell walls of E. coli which act as an adsorbing barrier preventing the access of the drug to its site of action.
A Safe Method of Exposing Microthreads in the Open Air
Authors: Druett H. A.
Published: March 2008

A safe method for exposing pathogenic organisms held on microthreads to realistic environmental conditions is described. The apparatus consists of an air duct in which the organisms on microthreads are exposed, and contiguous to it a safety cabinet, air from both systems being continuously extracted into high efficiency aerosol filters.
Fluorescent Spectrophotometry in the Identification of Bacteria
Authors: Ginell R. , Feuchtbaum Regina J.
Published: March 2008

Summary: Preliminary results on a technique for identifying bacteria by spectrophoto‐fluorometry are presented. The 3 parameters involved, emission wavelength, excitation wavelength and intensity, are used to produce a topographic map characteristic of the fluorescence of the chemical bonds. Enhancement of the differences between species is possible using dyes such as acridine orange. Various improvements in the technique are presented.
A Method for the Rapid Enumeration of Mycoplasma Species growing in Broth Culture
Authors: Windsor R. S. , Boarer C. D. H.
Published: March 2008

Summary: A method is outlined whereby Mycoplasma species growing in broth culture can be rapidly counted, using the relationship between the number of organisms and the mean lactate dehydrogenase (LDH) content of each organism. The uses of this technique are discussed.
An Apparatus for Dosing Laboratory Fermenters with Suspensions
Authors: Owens J. D. , Evans M. R.
Published: March 2008

Summary: The construction and operation of an apparatus for dosing laboratory fermenters semicontinuously with suspensions is described. The apparatus periodically measures a volume of slurry and then injects it into the fermenter. A control unit determines how often the cycle of operations is performed.
A Survey of Rhizobia in Farm Soils at Wye College, Kent
Authors: de Escuder Ana M. Q.
Published: March 2008

Summary: Numbers of Rhizobium meliloti, R. trifolii, R. leguminosarum and R. lupini in different fields near Wye, Kent, were determined by the ‘plant dilution’method. R. trifolii was most abundant, followed by R. leguminosarum, with R. meliloti and R. lupini less abundant and more restricted in their distribution. Isolates were made from nodules taken from the highest dilutions of soil that produced nodules and were tested for effectiveness in fixing nitrogen in agar tube culture. In general, isolates were effective or fairly effective. Highly effective isolates of R. trifolii were found in a very calcareous soil which had grown barley for 9 years. A permanent pasture which received higher doses of N fertilizer than other fields, contained strains of R. trifolii with a wider range of effectiveness, some giving only 50% of the dry matter production of the standard strain. The survival of R. meliloti 2001 in fields in which lucerne had not been grown for 9—14 years was studied, using a serological technique. No isolate was identified with certainty as strain 2001, but 55 of the 110 isolates tested showed some common features with this strain.
Nucleic Acid and Protein Synthesis in Reconstituted Lyophilized Escherichia coli Exposed to Air
Authors: Novick O. , Israeli E. , Kohn A.
Published: March 2008

Summary: Escherichia coli strain BT‐, freeze dried from distilled water, loses viability by exposure to air in the dry state, and decay curves of such bacteria were determined. The amounts of tritiated thymidine incorporated in the DNA of such ‘dead’, rehydrated bacteria are compatible with an assumption that the synthesis of DNA proceeds till the completion of its replication cycle, but not beyond. Induction of β‐galactosidase served as an indicator of RNA and protein synthesis in the dead bacteria. Such induction occurred after a short lag after which it proceeded at a rate similar to that observed in lyophilized, untreated bacteria. The loss of viability of these bacteria cannot be accounted for by defects in the production of DNA or RNA and protein synthesis; it is most probably due to damage to the DNA initiation point.
Mathematical‐Ecological Aspects of the Examination for Enterobacteriaceae of Foods Processed for Safety
Authors: Drion E. F. , Mossel D. A. A.
Published: March 2008

Summary: When the minimum proportion of Enterobacteriaceae to salmonellae in dried foods processed for safety is of the order of 103, as the authors' surveys show them to be, testing 1 or 2 × 1 g aliquots for Enterobacteriaceae and allowing no positives confers the same degree of consumers' protection as examining 60 × 25 g amounts directly for salmonellae and accepting the consignment only when no positives are detected.
Some Properties of the Nonsporing Anaerobes from Poultry Caeca
Authors: Barnes Ella M. , Impey C. S.
Published: March 2008

Summary: A study has been made of the ability of 48 strains of anaerobic bacteria, representing 20 different groups of Gram negative and Gram positive nonsporing rods and peptostreptococci, isolated from poultry caeca, to attack certain substrates that may be of ecological importance. The organisms were predominantly saccharolytic; only the strains of Propionibacterium acnes showed proteolytic activity. None of the strains hydrolysed amorphous cellulose or xylan. A few were weakly pectolytic. Starch was hydrolysed by all the strains of Bacteroides fragilis and by one strain of Eubacterium. Two groups of Gram negative bacteria (Bacteroidaceae) and one of the peptostreptococci attacked uric acid. The resistance of the anaerobes to inhibitory substances (bacitracin, virginiamycin, kanamycin, neomycin, vancomycin and nalidixic acid) was determined. Selective media for the isolation of certain of the groups of Gram negative anaerobes have been developed.
Effects of Plasticizers and Plastic Coatings on Fungal Attack of Cotton Yarn
Authors: Stewart C. S. , Walsh J. H.
Published: March 2008

Summary: The presence of PVC plasticizers inhibits fungal attack on cotton yarn to various extents. Some plasticizers apparently prevent attack of yarn by inhibiting fungal growth whilst others are utilized in preference to cellulose. The fungal penetration of plastic coated cotton yarn was enhanced by incorporating susceptible plasticizers. Attempts to relate attack on coated yarn by fungi to tolerance of more anaerobic conditions were only partly successful.
Inactivation of Strains of Salmonella senftenberg by Gamma Irradiation
Authors: Underdal B. , Rossebo L.
Published: March 2008

Summary: Strains of Salmonella senftenberg isolated from Norwegian herring meal and strain 775W were exposed to gamma radiation from a 60Co source. When they were irradiated in phosphate buffered saline solution, the average D10 values for all the strains was 19·3 krad. On irradiating strains 56 and 775W in herring meal the D10 values were 192·1 and 188·5 krad, respectively, thus indicating that the suspending medium had a great effect on the radiation resistance of the organisms. Radiation doses of the order of 0·8–1·3 Mrad are recommended for the decontamination of herring meal.
Bacteria Antagonistic to Pseudomonas tolaasii and their Control of Brown Blotch of the Cultivated Mushroom Agaricus bisporus
Authors: Nair N. G. , Fahy P. C.
Published: March 2008

Summary: Pseudomonas tolaasii was isolated from casing peat of healthy and diseased mushroom beds, compost of diseased mushroom beds and from soils round a mushroom farm. It was not isolated from fresh peat or compost from healthy mushroom beds. Three bacteria antagonistic to Ps. tolaasii were isolated from soil and peat. These were a nonfluorescent Pseudomonas sp. (closest to Ps. multivorans) from soil; and strains of Ps. fluorescens and Enterobacter aerogenes from peat. When the antagonists and the pathogen were added in the ratio of 8 × 107: 106 cells/ml to unsterilized peat and applied to mushroom trays, infection of mushroom sporophores by the pathogen was effectively controlled. In vitro studies failed to show lysis or growth inhibition of Ps. tolaasii by the antagonists.
The Destruction of Byssochlamys fulva asci by Low Concentrations of Gaseous Methyl Bromide and by Aqueous Solutions of Chlorine, an Iodophor and Peracetic Acid
Authors: Ito K. A. , Seeger Marcia L. , Lee W. H.
Published: March 2008

Summary: Byssochlamys fulva asci are resistant to high concentrations of aqueous chlorine and iodophor solutions, but are sensitive to peracetic acid. Concentrations of 2% and 4% of peracetic acid gave 99·9% reductions in 2·5 and 1·3 min, respectively. The asci were also sensitive to methyl bromide gas (MeBr), c. 5 × 104 asci/g inoculated into tapioca starch powder (aw= 0·69) being killed in 30 days by 90 mg of MeBr/kg of starch. About 180 asci/g were killed by adding 60 mg of MeBr/kg of starch.
Biological Control of Crown Gall: Seed Inoculation
Authors: Kerr A.
Published: March 2008

Summary: Peach seeds were inoculated with the nonpathogenic isolate 84 of Agrobacterium radiobacter var. radiobacter biotype 2 before sowing in natural soil heavily inoculated with the tumour inducing biotype 2 isolate 27 (A. radiobacter var. tumefaciens). Nonpathogens (presumably isolate 84) became predominant in the biotype 2 population on roots, on underground stems and in the soil round plant crowns. Significant (P < 0·001) biological control of crown gall was achieved. Total gall incidence on plants grown from inoculated seed was 31% and from uninoculated seed 79%; the corresponding gall incidence on plant crowns was 12% and 76%. Dusting seed with Thiram (3·1 g/kg seed) did not significantly reduce disease incidence. Infection appeared to occur through undamaged lenticels indicating that wounding is not a necessary prerequisite for crown gall induction in peach.
Fermentation of Cane Molasses by Yeasts after Preservation under Conditions of High Sugar Concentration
Authors: Rose D.
Published: March 2008

Summary: Fermentations of cane molasses solutions by sugar‐tolerant flocculating strains of Saccharomyces cerevisiae Sa. 28 and Sacch. carlsbergensis Sa. 23, produced compact sediments from which supernatant liquid could be decanted easily. Immediate treatment of the residual yeast with molasses containing 70·2% w/v total sugars (64° Brix) at 20°, engendered viabilities of 21·9–58% and 0·043–0·25% after 3 and 100 days, respectively. Dilution of the molasses caused culture recovery with fermentation, the initial rate of which could be correlated with the % viability of the yeast culture. The technique of preserving yeast cultures by use of concentrated sugar solutions warrants further investigation and could perhaps find application in distillery practice.