bluuebunny/crossref_metadata_2025 huggingface dataset:
The microbial degradation of morpholine
Authors: Knapp J.S. , Callely A.G. , Mainprize J.
Published: March 2008

Morpholine can be completely degraded microbiologically, and two organisms have been isolated, each capable of growth in a simple mineral salts medium with morpholine as the sole source of carbon, nitrogen and energy. Excess nitrogen is liberated as ammonia. The enzymes responsible for the oxidation of morpholine are inducible and, in organism Mor G, will also oxidize piperidine, piperazine and pyrrolidine, which are not growth substrates. Ethanolamine is a likely intermediate, though the metabolic steps in morpholine degradation do not give rise solely to acetyl‐CoA. After a period of acclimation, a laboratory scale activated sludge plant effectively removed morpholine over the long period it was operated; the sludge was also capable of nitrification. The possible effects of other chemicals in trade wastes containing morpholine on nitrification and morpholine oxidation are described.
Injury and recovery of Bacillus megaterium from mild chlorhexidine treatment
Authors: Nadir May T. , Gilbert P.
Published: March 2008

Treatment of Bacillus megaterium cell suspensions with 12 /μmol/1 chlorhexidine diacetate for 5 min led to an approximate 50%, reduction in viability when plated onto tryptone soya agar (TSA). Fifty percent of the surviving fraction were unable to form colonies on TSA containing 5.5% w/v KCI. Such loss of KCl tolerance is indicative of membrane damage, and was recovered within 30 min of incubation in tryptone soya broth (TSB). Multiplication of the damaged organisms did not recommence in this medium until after 60 min. Inclusion of inhibitors of respiration, and of protein, RNA and DNA synthesis in the TSB recovery medium did not significantly affect either the rate or extent of the recovery of KCl tolerance by damaged organisms.
Production of L‐ AND D‐lactate by Pediococcus pentosaceus in batch and steady‐state continuous culture
Authors: Häggström Margareta H. , Andersson E.
Published: March 2008

The fast growth and acid production of a strain of Pediococcus pentosaceus, used as a starter culture in the production of dry sausages, was dependent on the presence of acetate. In a batch culture on a mixture of glucose and sucrose both sugars were consumed simultaneously. Similar growth rates and product yields were obtained on glucose and sucrose, d‐ AND l‐lactate were produced via a D‐ and L‐lactate dehydrogenase (LDH), respectively, and no racemase was present. In batch cultures about 15% of the lactic acid produced was the D‐isomer, whereas in a sucrose‐limited, continuous culture the fraction of D‐lactic acid increased with decreasing dilution rate. The results are discussed in relation to the two LDH activities.
Improved Salmonella recovery from moderate to highly polluted waters
Authors: Alcaide E. , Martínez J.P. , Martínez‐Germes P. , Garay E.
Published: March 2008

A new enrichment procedure for the recovery of salmonellas from aquatic environments is proposed. It has been tested in a eutrophic lake showing moderate to high faecal contamination levels (the Albufera lake near Valencia, Spain), and in effluents coming into a wastewater treatment plant. The new method consists of the addition of sodium novobiocin to a modification of Rappaport's medium (R10/43°C). The new medium (NR10/43°C) allows a better recovery of salmonellas from water than selenite broth.
Optimized dipicolinate activation for viable counting of Bacillus stearothermophilus spores
Authors: Kirk B. , Hambleton R.
Published: March 2008

Spores of Bacillus stearothermophilus were exposed to calcium and sodium salts of dipicolinic acid (DPA) in phosphate and Tris acid maleate buffers over the range pH 4.5–10.0. The exposed spores were enumerated using a standard plate counting technique from which the kinetics of colony formation were determined and maximum colony counts were obtained for each condition examined. Exposure of the spores to calcium‐DPA (50‐40 mmol/l) in Tris acid maleate buffer pH 9.0 maintained at 10°C was found to produce an optimal response. Following this method the total viable population of a spore suspension was enumerated. This was demonstrated statistically using the Wilcoxon rank‐sum test for significance. Calcium‐DPA was found to produce activation in spores but further germinants and nutrients were required for colony formation. The Ca‐DPA treatment was found to be effective in enumerating both naturally dormant spores and heat injured spores.
The removal of Salmonella enteritidis in activated sludge
Authors: Yaziz M.I. , Lloyd B.J.
Published: March 2008

Salmonella destruction efficiencies of 99% were obtained after 10 h aeration at 15°C in a laboratory model of the activated sludge process. This study demonstrated that, in a batch process, the removal of salmonellas occurred in three phases. (i) By 4 h, 90% of the original inoculum had disappeared from the activated sludge, probably due mainly to predation by ciliated protozoa. The remaining 10% was distributed between the liquid phase (approximately 90%) and the sludge floc (approximately 10%). (ii) During the next 2 h this situation was inverted so that, by 6 h, more than 80% of the remaining salmonellas were then adsorbed to floc, leaving less than 20% in liquid suspension. (iii) From 6 h onwards there was a much slower decline of the remaining salmonellas attached to floc. The addition of dioctyl sodium sulphosuccinate after 4 h, inactivated the ciliated protozoa populations and completely eliminated the continued reduction of salmonellas from activated sludge observed previously.
The populations, characterization and activity of suspended bacteria in the Welsh River Dee
Authors: Nuttall D.
Published: March 2008

In a 29 month study of bacterial populations at three sites on the Welsh River Dee, the aerobic heterotrophic bacteria increased from an average basal level of about 1.2 times 104 colony‐forming units (cfu)/ml near the source of the river, to 2 times 105 cfu/ml in the lower reaches. The ratio, total bacterial cell count: viable count, decreased from 70 in the upland reaches to 10 in the lower parts of the river. There was no apparent seasonal variation in bacterial numbers but on occasions the bacterial populations in both upland and lowland reaches of the river increased simultaneously. Fluctuations in bacterial numbers over a 50‐fold range were observed in this study. Bacterial isolates from both upland and lowland sites were predominated by two groupings of bacteria, the Pseudomonas—Agrobacterium—Alcaligenes group and the Flavobacterium—Cytophaga—Flexibacter group. Results suggested that the latter group may have been part of the autochthonous population. Seasonal variation in heterotrophic potential (Vmax) for acetate uptake was shown to occur over a 30‐fold range in the lowland reaches of the River Dee. Peaks in activity at the lowland site occurred during the summer months, the range of Vmax values for acetate ranged from 0.2 to 30 μg/1/h. Fluctuations in Vmax values from the upland site were not seasonal but were instead linked to faecal pollution, Vmax values from this site range from 0.04 to 3 μg/1/h.
Heat resistance studies of yeasts; vegetative cells versus ascospores: erythromycin inhibition of sporulation in Kluyveromyces and Saccharomyces species
Authors: Put Henriette M.C. , Jong J. De
Published: March 2008

A comparative study of the heat resistance (D60 values) of four Saccharomyces spp. and two Kluyveromyces spp. (21 strains) showed a 30–350‐fold higher heat resistance of ascospores than of vegetative cells. It was also observed that small numbers of ascospores exhibiting a considerably higher heat resistance can easily be formed, even in a complete vegetative growth medium. This phenomenon may have led most other authors to report none or only slight differences between the heat resistance of yeast ascospores and their vegetative cells. Until more information has been collected about the ascospore load of acid (fruit) products and their heat resistance, accurate calculations of the minimum F values for heat preservation of these products may not be possible.
Pseudomonas tolaasii in cultivated mushroom (Agaricus bisporus) crops: numbers of the bacterium and symptom development on mushrooms grown in various environments after artificial inoculation
Authors: Wong W.C. , Preece T.F.
Published: March 2008

The recovery of Pseudomonas tolaasii applied to peat, limestone and mushroom caps, is very difficult, recovery rates being 0.2–16.0%. Without Agaricus bisporus mycelium, inoculated Ps.tolaasii disappears in the casing layer. As mushroom primordia grew in size on inoculated mushroom beds, the number of detectable cells of the pathogen increased. Symptoms of blotch disease became visible when 5.4 times 106 cfu were detectable, when the mushroom primordia were 6 mm in diameter; 60% of mushrooms showed symptoms before they were 15 mm in diameter. Application of Ps.tolaasii cells as low as 20 cfu/cm2 of bed gave epidemics of this severity. Neither size nor age of mushrooms affects their susceptibility. When Ps.tolaasii was placed directly onto caps, 6 times 107 cfu were necessary to produce a blotch lesion (though only 3.5 times 106 cfu could be recovered). Changes in r.h. and temperature did not affect the numbers of cells of Ps.tolaasii on inoculated caps; very frequent watering did so. Increased severity of the disease was seen only on over‐watered mushrooms; this occurred by increase in the size of lesions seen at the primordium stage. The number of cells of Ps.tolaasii present on the early primordial stages of mushroom growth controls the extent of blotch disease seen at harvesting, whereas variations in r.h. or temperature during growing do not do so. An illustrated disease symptom measurement key (of general application for assessing severity of blotch disease) is included in the text.
A note on the isolation and enumeration of Gram positive cocci from marine and estuarine waters
Authors: Gunn B.A. , Singleton F.L. , Peele E.R. , Colwell R.R.
Published: March 2008

Ninety‐two percent of Gram positive cocci detected in estuarine and marine surface waters were identified as Staphylococcus spp. Micrococcus and Streptococcus spp. were rarely isolated from seawater, except at dump site stations located in the Puerto Rico Trench area of the Atlantic Ocean, where they were present in unusually large numbers. Staphylococci were present in greatest abundance near land, but were also found in open ocean surface waters in low, but relatively constant, numbers. Staphylococcus epidermidis, or strains related to Staph. hominis, were present in all samples. Staphylococci from surface water samples collected at the Puerto Rico Trench dump site degraded a wide range of compounds. It is considered that these cocci were derived from the wastes dumped, as very few were found in unpolluted marine waters and in those cases in which stimulatory factors, such as disposal of wastes, do not play a role, Gram positive cocci will not be recovered unless large volumes of water are filtered. The Gram positive cocci are present in very low numbers in natural seawater of the open ocean and, therefore, are commonly overlooked. The significance of these bacteria in the nutrient cycles of the sea remains to be elucidated. Documentation of a widespread occurrence of Gram positive cocci in North Eastern Atlantic seawater is provided.
Growth at sub‐zero temperatures of black spot fungi from meat
Authors: Gill C.O. , Lowry P.D.
Published: March 2008

Glycerol can prevent both freezing and desiccation of micro‐organisms growing at sub‐zero temperatures. On media containing glycerol, at concentrations readily tolerated by the organisms at ambient temperatures, three species of fungi isolated from black spot spoilt meat failed to grow at temperatures much below ‐5°C. This would, therefore, seem to be the minimum possible growth temperature of these organisms. Although the fungi could grow on frozen media, their rates of growth were such that, on frozen meat, several months would be required for colonies to become barely visible. It therefore seems that significant black spot spoilage will only develop on frozen meat if it is held at temperatures within 2–3° below the freezing point for prolonged periods, or if the meat surface reaches higher temperatures with surface drying inhibiting bacterial growth. There has been little study during the last 50 years of mould spoilage of meat, although it is still of importance in the international trade in frozen meats. Because moulds grow relatively slowly, they only spoil meat if the storage conditions prevent bacterial growth, but there are few firm data on the time and temperature requirements for visible mould growth to develop in the absence of bacterial spoilage. Such data are necessary if the causes of particular outbreaks of fungal spoilage are to be assessed correctly.
A new screening method for investigating microbial interactions
Authors: MacFarlane T.W. , Makrides H.C.
Published: March 2008

Interactions among Candida albicans, Staphylococcus aureus and Escherichia coli were investigated using a screening system in which test micro‐organisms were incorporated in agar discs and effector micro‐organisms in fluid growth media. Total as well as partial inhibition of test micro‐organisms was observed in agar discs when these were incubated in broths containing effector micro‐organisms. The ratio of numbers of test to effector micro‐organisms was found to be of importance in the inhibition effect. The technique was found to be cheap, simple and versatile.
A note on the effect of growth temperature on the production of amylases by the yeast Lipomyces kononenkoae
Authors: Estrela A.I. , Lemos M. , Spencer‐Martins I.
Published: March 2008

The production of glucoamylase and α‐amylase by the yeast Lipomyces kononenkoae IGC 4052 at growth temperatures between 15 and 36°C has been studied. Glucoamylase production was found to be independent of growth temperature. α‐Amylase production had a temperature optimum in the range 25–28°C. The yield of growth on starch was not influenced by growth temperature.
The influence of glucose concentration and culture incubation time on end‐product formation during aerobic growth of Brochothrix thermosphacta
Authors: Dainty R.H. , Hofman F.J.K.
Published: March 2008

Fifteen strains of Brochothrix thermosphacta, isolated from various meat sources, produced the same end‐products during aerobic growth in a tryptone‐based medium containing 0.2% (w/v) glucose. Growth of one strain at different glucose concentrations showed that 2‐methylpropanol and 2,3‐butanediol were also produced. Formation of the branched chain acids was favoured by low glucose concentrations, that of the alcohols and the diol by higher concentrations. The traces of the diol, but not those of the alcohols, produced during the early stages of growth at low, limiting concentrations of glucose, gradually disappeared following glucose depletion. These findings provide adequate explanations for the observed differences in end‐product formation during growth of Broc. thermosphacta on non‐processed and corned beef.
The adherence of lactic acid bacteria to the columnar epithelial cells of pigs and calves
Authors: Mäyrä‐Mäukinen Annika , Mnninen Merja , Gyllenberg H.
Published: March 2008

The adhesion of various lactobacilli and streptococci to columnar epithelial cells of pigs and calves were studied, by in vitro methods. The porcine strains isolated most frequently were Lactobacillus delbrueckii, Lact. acidophilus and Lact. fermentum. Thirteen of the 22 lactobacilli were adhesive. All the streptococci isolated belonged to Lancefield's D‐group; none of them adhered to pig epithelial cells. The adhesive strains (9 of 22) of calves were identified as Lact. fermentum. Adherence was variable even between strains of the same species. Isolates from plant material, cultured milk and cheese did not adhere to the columnar epithelial cells in vitro. The adhesive porcine strains tolerated low pH and bile acids, which is important for their survival under conditions in the stomach and intestine.
Comparison of direct and indirect immunoradiometric assays (IRMA) for Bacillus anthracis spores immobilised on multispot microscope slides
Authors: Phillips A.P. , Martin K.L.
Published: March 2008

A solid phase immunoradiometric assay (IRMA) is described in which Bacillus anthracis spores were heat fixed to the wells of glass multispot microscope slides. Assays for spores of B. anthracis Vollum and Sterne strains with 3H labels were evaluated in the direct and indirect versions. Neither signal nor signal‐to‐noise characteristics of indirect assays were greatly improved by the use of immunopurified antibody (IPAB) or IgG anti‐bacterial reagents rather than antiserum. However, the specificity of the direct and indirect assays for B. anthracis strains and B. cereus NCTC 8035 was altered by immunopurification of the anti‐bacterial reagent. Although the signal‐to‐noise ratio was sometimes higher in indirect than in direct assays, signal values were usually no better. Evidence was produced that the overall ratio of the indirect: direct antibody molecules bound by preparations of B. anthracis spores rarely exceeded two but the antibody‐molecular ratio for antigens on extracellular material in spore preparations was much higher than the ratio for antigens on the spores themselves.
Genus Bacteroides A chemotaxonomical perspective
Authors: Shah H.N. , Collins M.D.
Published: March 2008

1. Introduction, 403

2. Acid end products, 403 3. DNA base composition, 404 4. Cell walls, 404 5. Enzymes, 407 6. Lipids, 408 6.1 Pigments, 408 6.2 Fatty acids, 408 6.3 Polar lipids, 409 6.4 Menaquinones, 411 7. Taxonomic considerations, 412 8. Conclusions, 414 9. References, 414
Nitrite loss and spoilage microflora development in chub‐packed luncheon meat
Authors: Bell R.G. , Lacy Karen M. De
Published: March 2008

Residual nitrite was lost from chub‐packed luncheon meat during storage through both chemical breakdown and microbial consumption. The relative importance of these mechanisms in this pasteurized product was determined by the speed of development of the spoilage microflora, which is influenced by storage conditions. The nitrite half‐life due to chemical loss was 13 d at 25°C and 36 d at 10°C. When microbial growth occurred these half‐lives were reduced to 2.6 d and 21 d, respectively. Qualitative differences in the microflora that developed at these two temperatures (denitrifying Bacillus spp. at 25°C and non‐denitrifying Streptococcus spp. at 10°C) account for the large temperature effect. Growth of Streptococcus spp. increased the rate of chemical nitrite loss in chubs by reducing the pH value. Nitrite did not inhibit the aerobic growth of either Bacillus or Streptococcus species associated with spoilage but did inhibit the anaerobic growth of Bacillus spp. This bacteriostatic effect of residual nitrite in anaerobic conditions will decrease during storage as nitrite level falls and oxygen penetrates the chub pack. Nitrite‐mediated bacteriostasis does not obviate the need for refrigerated storage but does afford a real, if ephemeral, safeguard against spoilage occurring during short periods of temperature abuse.
Amylase production by three Lactobacillus strains isolated from chicken crop
Authors: Champ Martine , Szylit Odette , Raibaud P. , Aïut‐Abdelkader Nadra
Published: March 2008

Three amylolytic Lactobacillus strains designated LEM 220, LEM 207 and LEM 202 were isolated from the chicken crop. They belonged to the subgenus Thermobacterium. Strain LEM 220 resembled Lact. acidophilus. Amylase production was more abundant in cells grown in media containing amylopectin or starch than in media containing glucose or maltose. Optimum pH and temperature of the amylase were 5.5 and 55°C respectively. Hydrolysis of amylopectin gave maltose, maltotriose and small amounts of glucose. Strain LEM 207 also resembled Lact. acidophilus, but differed from strain 220. It had a lower amylase activity. Optimum pH and temperature of the amylase were 6.4 and 40°C, respectively, and hydrolysis of amylopectin gave maltose, maltotriose and carbohydrates higher than maltopentaose. Strain LEM 202 was similar to Lact. vitelinus. It had the lowest amylase activity which was increased only in presence of maltose. Amylase properties were similar to those of LEM 220.
A note on inhibition test and electrophoretic detection limits of antibiotics used in British animal husbandry
Authors: Bates M.L. , Lindsay D.G. , Watson D.H.
Published: March 2008

A four plate microbiological inhibition test (the FPT) and a bioelectrophoretic method were evaluated for their ability to detect a range of antibiotic agents, which may be present as residues in animal tissues following their therapeutic use in animal husbandry. Both methods exhibited a wide range of sensitivities and several of the tested antibiotics could not be detected by either method. The pattern of responses across the bacterial plates in the FPT could not be used to identify agents and the bioelectrophoretic inhibition zone diameters were generally too large to allow the use of Rs values for identification. The Bacillus subtilis pH 7.2 plate with trimethoprim added was as effective as the four bacterial plates used in the FPT in antibiotic detection.
Enterotoxin production by atypical Staphylococcus aureus from poultry*
Authors: Evans J.B. , Ananaba G.A. , Pate C.A. , Bergdoll M.S.
Published: March 2008

Phenotypically typical Staphylococcus aureus was isolated frequently from the necrotic bone and liver of poultry suffering from femoral head necrosis. Occasionally strains were isolated that differed from typical Staph. aureus in one or more of the major diagnostic tests, i.e. coagulase production, anaerobic fermentation of mannitol and production of a heat‐stable deoxyribonuclease. Such atypical strains were also isolated from nasal swabs of healthy birds. Tests for enterotoxin production demonstrated that some atypical strains from both sick and healthy birds are capable of producing staphylococcal enterotoxins.
Microbial growth at reduced water activities: studies of aw prediction in solutions of compatible solutes
Authors: Chirife J. , Alzamora S.M. , Fontan C. Ferro
Published: March 2008

Studies were made of the prediction of intracellular water activity (aw) of microorganisms grown at reduced aw. These included the determination and prediction of aw of potassium L‐glutamate solutions and the prediction of aw in mixed solutions of various compatible solutes and macromolecules. Compatible solutes studied were L‐proline, glycerol, potassium chloride and D‐arabitol. The results indicate that aw predictions of such mixtures may be done with acceptable accuracy by neglecting solute‐solute interactions.
Factors affecting the survival of Salmonella and Escherichia coli in anaerobically fermented pig waste
Authors: Henry D.P. , Frost A.J. , Samuel J.L. , O'Boyle D.A. , Thomson R.H.
Published: March 2008

The survival of Salmonella typhimurium was investigated in acidogenic, anaerobically fermented pig wastes and in synthetic media, each containing volatile fatty acids (VFA). Salm. typhimurium survived at pH 6·8, but not at pH 4·0, when incubated at 37°C for 24 h in either fermented or synthetic medium containing VFA. The minimum inhibiting concentration of VFA for Salm. typhimurium after 48 h incubation at 30°C at pH 4·0 was 0·03 mol/l and for Escherichia coli it was 0·09 mol/l. Fermented pig wastes in a digester, maintained at pH 5·9, were inoculated with Salm. typhimurium and then incubated at 37°C for 24 h. The pH was adjusted to either 4·0 or 5·0 and after a further 48 h at 30°C, Salm. typhimurium survived at pH 5·0 but not at pH 4·0. It was concluded that pH is critical in determining the survival of this organism in acidogenic anaerobically fermented pig waste.
Microculture model studies on the effect of various gas atmospheres on microbial growth at different temperatures
Authors: Eklund T. , Jarmund T.
Published: March 2008

A microculture technique, employing 96‐well tissue culture plates in plastic bags, was used to test the effect of different gas atmospheres (vacuum, air, nitrogen, and carbon dioxide) on the growth of Escherichia coli, Bacillus macerans, Salmonella typhimurium, Candida albicans, Lactobacillus plantarum, Pseudomonas Acinetobacter/Moraxella‐group, Brochothrix thermosphacta and Yersinia enterocolitica at 2, 6, and 20°C. In general, carbon dioxide was the most effective inhibitor. The inhibition increased with decreasing temperature. Only the combination of carbon dioxide and 2°C provided complete inhibition of Broch. thermosphacta and Y. enterocolitica.
The presence of oxygen in rumen liquor and its effects on methanogenesis
Authors: Scott R.I. , Yarlett N. , Hillman K. , Williams A.G. , Lloyd D. , Williams T.N.
Published: March 2008

In situ measurement of O2 in the rumen liquor of cows, sheep and goats using a membrane‐covered O2 electrode revealed the presence of up to 1630 nmol/l O2; O2 became undetectable immediately after feeding of animals. The effects of O2 on H2 production and methanogenesis in samples of rumen liquor were investigated using a mass spectrometer fitted with a membrane inlet system. Methanogenesis was totally and irreversibly inhibited after short term exposure (about 10 min) to 5 KPa (0·05 atm) O2; H2 production was unaffected. Glucose additions produced rapid transient increases in H2 levels and increased O2 uptake.
A simplified system for biotyping Staphylococcus aureus strains isolated from different animal species
Authors: Devriese L.A.
Published: March 2008

Devriese, L.A. 1984. A simplified system for biotyping Staphylococcus aureus strains isolated from different animal species. Journal of Applied Bacteriology56, 215–220.

A biotyping system for Staphylococcus aureus strains is proposed which is a simplified version of biotyping procedures described in the literature. It differentiates Staph. aureus strains from man and animals into host‐specific ecovars and biotypes which are not host‐specific. With the help of tests for βhaemolysin, staphylokinase, coagulation of bovine plasma and the crystal‐violet reaction, the origin of many but not all Staph. aureus strains can be determined: 604 of 809 strains from man. poultry, cattle, pigs, goats, rabbits and foods could be alloted to four ecovars which are typically associated with man, poultry, sheep and goats and cattle. The other strains belonged to five non‐host specific biotypes.
The effect of udder infection on the bacterial flora of the bulk milk of ten dairy herds
Authors: Bramley A.J. , McKinnon C.H. , Staker R.T. , Simpkin D.L.
Published: March 2008

The significance of udder infection as a factor increasing the bacterial count of herd bulk milk was measured monthly for one year in ten dairy herds in Southern England. Staphylococcus aureus or mastitis streptococci were detected in 86% of samples, usually in numbers between 1000 and 10 000 c.f.u./ml of milk. However, in 8 and 2% of samples respectively > 20 000 or 100 000 c.f.u. of mastitis pathogens/ml of milk were detected. This occurred most commonly in the herds with a high incidence of Streptococcus uberis mastitis. The total bacterial counts of the herds' milks varied between 13 960 and 46 230 c.f.u./ml in the winter and between 6510 and 63 000 c.f.u./ml in the summer. No correlation was found between bacteriological quality of herd milk and the cleanliness of the milking machine and pipeline as assessed by plant rinses.
Production and properties of a bacteriocin from Myxococcus coralloides D
Authors: Muñoz J. , Arias J.M. , Montoya E.
Published: March 2008

Myxococcus coralloides D was found to produce a substance with a narrow range of antibacterial activity. This substance was produced during the exponential growth phase and was not inducible by ultraviolet light or mitomycin C treatment. The bacteriocin was precipitable by ammonium sulphate, and showed resistance to heat (100°C for 10 min), trypsin, lysozyme, β‐glucuronidase, DNase, RNase, acetone, ethyl ether, urea and mercaptoethanol; it was partially destroyed by pronase and inactivated at extreme pH values. Electron microscopy did not reveal any phage‐like particles associated with bacteriocin activity.
Use of the Direct Epifluorescent Filter Technique for predicting the keeping quality of pasteurized milk within 24 hours
Authors: Rodrigues Ubaldina M. , Pettipher G.L.
Published: March 2008

The keeping quality (KQ) of pasteurized milk stored at 5°C and 11°C was predicted within 24 h by pre‐incubating samples and counting bacteria by the Direct Epifluorescent Filter Technique (DEFT). For samples from 5°C storage, 0.03% (w/v) benzalkonium chloride and 0.002% (w/v) crystal violet (final concentration) were added to inhibit the growth of Gram positive bacteria during pre‐incubation. The samples from milk stored at 11°C were pre‐incubated without the addition of inhibitors. After pre‐incubation there was a satisfactory relationship between the DEFT count and the KQ of milks at both 5°C and 11°C. The DEFT count following pre‐incubation correctly classified > 80% of pasteurized milks on the basis of KQ.
Emergence and development of resistance to antimicrobial chemicals and heat in spores of Bacillus subtilis
Authors: Gorman S.P. , Scott E.M. , Hutchinson E.P.
Published: March 2008

The emergence and development of chemical and thermal resistance in spores of Bacillus subtilis was examined. The chemicals studied were of the disinfectant type: glutaraldehyde, hypochlorite, hypochlorite‐methanol and povidone‐iodine. Growth and sporulation were followed by electron microscopy and resistance assigned to specific stages in relation to 45Ca and DPA accumulation. A sequential development of resistance was observed with thermal resistance appearing first at early Stage V corresponding to maturation of cortex and deposition of rudimentary spore coat material. Chemical resistance coincided with middle to late Stage V dependent on the chemical concerned. A progressive development of resistance was observed on prolonged incubation in sporulation medium and was affected by inclusion of lysozyme in the spore washing sequence.
Observations on the in vitro sensitivity and resistance of Gram positive intestinal bacteria of farm animals to growth promoting antimicrobial agents
Authors: Dutta G.N. , Devriese L.A.
Published: March 2008

Dutta, G.N. Devriese, L.A. 1984. Observations on the in vitro sensitivity and resistance of Gram positive intestinal bacteria of farm animals to growth promoting antimicrobial agents. Journal of Applied Bacteriology56, 117–123.

Results of qualitative in vitro sensitivity tests made with growth promoting antimicrobial agents on clostridia, lactobacilli and enteric streptococci, isolated from caeca of pigs, cattle and poultry, are summarized. The compounds were active in vitro against most of the 19 bacterial species studied. However, their activity spectra differed markedly. Only four bacterial species were naturally sensitive to all agents. The natural resistances, typical for many species and compounds, could be differentiated from the acquired resistances found with all growth promotors except avoparcin. High resistance and complex patterns of cross‐resistance involving one or more of the macrolide, lincosamide and streptogramin antibiotics were detected.
A note on potential hazards to animals grazing on pasture improperly treated with sewage sludge
Authors: WRAY C. , CALLOW R.J.
Published: March 2008

Sewage sludge was monitored for the presence of salmonellas after it had been dumped on a pasture so that it formed a number of extensive, thick pats. Although salmonellas were isolated from the sewage sludge, and also from grass and soil beneath the sludge for up to 94 days, they were not isolated from the faeces of grazing horses or surrounding drainage ditches. The results are discussed with regard to the possible hazards resulting from the use of sewage sludge on pasture.
A note on an antimicrobial agent in disc paper and a modified assay procedure for detecting antimicrobials in milk
Authors: GOODMAN G.D.H. , ISAÄCSON MARGARETHA
Published: March 2008

Commercially available disc paper used for antibiotic sensitivity tests was shown to contain an unidentified, water‐soluble agent inhibitory to Bacillus stearothermophilus which gave false positive results in an antimicrobial assay for milk. The agent however, was found to be inactive against a range of common pathogenic bacteria. It was easily removed by washing the discs in distilled water before use.
Serological characteristics of coagulase‐positive staphylococci isolated from man and animals
Authors: ADEGOKE G.O. , OJO M.O. , ADETOSOYE A.I.
Published: March 2008

A simplified method allowed Staphylococcus aureus, Staph. intermedius and coagulase‐positive Staph. hyicus subsp. hyicus isolated from humans, dogs, monkey, sheep, poultry, rabbits, giant rats (Cricetomys gambianus) and other animals to be serotyped. The nine coagulase‐positive staphylococcal strains of human origin possessed thermolabile and thermostable agglutinogens. Two strains of Staph. intermedius of human and canine origins examined had agglutinogen K1K2. The three Staph. aureus strains isolated from African giant rats (Cricetomys gambianus) had agglutinogens a5 and P common to them. The Staph. aureus strain isolated from a monkey belonged to serotype b1, c1, o and the caprine strain of Staph. hyicus subsp. hyicus was serotype a5, c1.
A note on a code for the identification of the ‘viridans’ streptococci
Authors: COOGAN MAEVE M.
Published: March 2008

A simple numerical code for the identification of ‘viridans’ streptococci was devised with Facklam's system of classification. This is based on biochemical criteria and consists of nine tests, with an additional five for the identification of closely related species and the subspecies or biotype ofStreptococcus mutans.The ‘viridans’ streptococci can be divided into 10 species with the aid of this scheme while five subspecies and an additional biotype ofStreptococcus mutanscan be recognized. Advantages of this scheme are that the numerical code differentiates between isolates of the same species, distinguishes between biochemically active and non‐active species and indicates similarities between species.
Contamination and bacterial retention capacity of beef carcasses at the abattoir
Authors: Kriaa H. , Arthaud J.F. , Fournaud Jeanne
Published: March 2008

Kriaa, H., Arthaud, J.F. & Fournaud, J. 1985 Contamination and bacterial retention capacity of beef carcasses at the abattoir. Journal of Applied Bacteriology 59, 23–28.

The contamination of beef carcasses was studied together with the capacity of meat surfaces to retain bacteria along the processing line in the slaughter hall.The results showed that the contamination varied along the processing line, but that this pattern was essentially dependent on the contamination at the dressing station. It decreased or remained unchanged during the first 12 min and then increased, even without additional contamination. The contamination varied according to carcasses and micro‐organisms studied and was not greatly affected by spray cleaning. The number of bacteria retained changed at a rate similar to that of the contaminants. The attachment was instantaneous. The results are discussed and compared with the various hypotheses about contamination and bacterial attachment processes.
Bacteria in bivalve shellfish with special reference to the oyster
Authors: Kueh Cathie S.W. , Chan Kwong‐yu
Published: March 2008

Kueh, C.S.W. & Chan, K‐Y. 1985. Bacteria in bivalve shellfish with special reference to the oyster. Journal of Applied Bacteriology, 59, 41–47.

The bacterial flora of the Pacific oyster Crassostrea gigas, the sea mussel Perna viridis and the arkshell clam Scapharca cornea differed considerably from that of seawater in both numbers and generic composition. The numbers of heterotrophic bacteria in the bivalve shellfish, including the anaerobes and spore‐forming bacteria, were greater than that in the surrounding water. Pseudomonas spp. were the dominant organisms, comprising over one third of the 321 strains characterized after isolation from the bivalves and seawater. Other bacteria isolated from the shellfish included Vibrio, Acinetobacter, and Aeromonas spp., whereas the seawater flora consisted mainly of coliform organisms, coryneform bacteria and Flavobacterium/ Cytophaga spp. Bacteria associated with the deposit‐feeding clams were higher in density and more distinct in generic composition as compared with those in the suspension‐feeding oysters and mussels. Over 90% of the coliform and heterotrophic bacteria in oysters were found in organs associated with the digestive tract. Coliforms were mainly found in the stomach while heterotrophs were present in both stomach and the lower intestine. The results suggest that the stomach flora of oysters are mainly derived from the external environment and, through a process of selection and multiplication, that it may be gradually replaced by a more indigenous population which dominates the lower digestive tract.
Antibiotic and deoxycholate resistance in Campylobacter jejuni following freezing or heating
Authors: Humphrey T.J. , Cruickshank J.G.
Published: March 2008

Humphrey, T.J. & Cruickshank, J.G. 1985. Antibiotic and deoxycholate resistance in Campylobacter jejuni following freezing or heating. Journal of Applied Bacteriology59, 65–71.

The surviving populations of Campylobacter jejuni serotypes following freezing or heat were found to be more sensitive to rifampicin and sodium deoxycholate on subsequent culture. Thus while control cultures had an IC50 of greater than 20 μg/ml rifampicin those of injured cells were <5 μg/ml. Treatment with EDTA caused almost identical changes in resistance suggesting that the altered resistance pattern of injured cells was due to loss of the barrier properties of the bacterial outer membrane.
Biotransformation of sugar‐cane sterols into Androsta 1,4‐dione‐3,17‐dione (ADD) by Arthrobacter globiformis Str. Oxydans
Authors: Srivastava S.K. , Srivastava R.A.K. , Mathur S.N.
Published: March 2008

Arthrobacter globiformis isolated from garden soil was cultured on phosphate salt medium containing phytosterols extracted from sulphitation pressmud, a sugar industry waste, as sole source of carbon. The bacterium grew well on sterols and transformed them into precursors of steroidal drugs and hormones. Addition of α,α′‐dipyridyl and sodium arsenite as metabolic inhibitors in the culture medium enhanced the accumulation of a 17‐ketosteroid which acts as precursor of steroidal drugs. The optimum temperature and pH conditions for its maximum accumulation were found to be 32 ± 0.5d̀C and 7.2. Spectroscopic analyses by u.v., i.r., p.m.r. and mass spectra of the 17‐ketosteroid formed by microbial activity in the medium confirmed it to be androsta‐1,4‐diene‐3,17‐dione (ADD). The bioconversion of sugar‐cane sterols into 17‐ketosteroid in varying culture condition is discussed.
Preparation of simulated clinical material for bacteriological examination
Authors: Demello J.V. , Snell J.J.S.
Published: March 2008

The preparation of mixtures of bacteria to mimic the flora found in pathological material is described. Such mixtures are useful for teaching, for practical examinations, for quality control of media and methods and for use in quality assessment schemes. The design of suitable mixtures is discussed and the stabilities of mixtures in transport media and in freeze‐dried preparations are compared. Transport media provide short term storage for periods of several weeks and, with various modifications, are moderately successful with some, but not all, quite delicate pathogens. Freeze‐drying however, provides greater stability over periods of months, allows preservation of delicate pathogens and is the preferred method where specimen quality is important.
High‐performance liquid chromatographic identification of beta‐lactam antibiotics produced by dermatophytes
Authors: Lappin‐Scott H.M. , Rogers M.E. , Adlard M.W. , Holt G. , Noble W.C.
Published: March 2008

Thirteen of 48 dermatophyte isolates were found by bioassay to produce beta‐lactam antibiotics and seven produced other antibiotics. Estimation and detection of specific beta‐lactams in culture broths by derivatization and HPLC was only possible following concentration and extraction procedures. Analysis of the concentrated broths demonstrated the production of penicillin X and penicillin G by two Trichophyton mentagrophytes strains and by one Microsporum canis strain; one further T. mentagrophytes strain produced only penicillin X. Additions of the beta‐lactam side‐chain precursors, phenylacetic acid and phenoxyacetic acid, to fermentation media failed to increase the antibiotic titres.
The direct epifluorescent filter technique (DEFT): increased selectivity, sensitivity and rapidity
Authors: Rodrigues Ubaldina M. , Kroll R.G.
Published: March 2008

With the direct epifluorescent filter technique (DEFT), differentiation of bacteria was achieved by a modified Gram‐staining procedure using acridine orange as the counterstain. The method enumerated viable Gram‐negative and all Gram‐positive bacteria. Counts of clumps of orange fluorescent cells (Gram‐negative DEFT count) correlated well with colony counts of Gram‐negative bacteria in samples of raw milk (r= 0·94). The use of stainless steel membrane filter supports and the addition of citrate‐NaOH buffer (0·1 M, pH 3·0) during filtration enabled 10 ml samples of milk to be filtered, thereby increasing the sensitivity of the DEFT five‐fold. The relationship between colony and DEFT counts with 10 ml samples was better (r= 0·90) than that using standard 2 ml samples (r= 0·88). Alternatively, these modifications in procedure allowed the preincubation time for 2 ml milk samples to be reduced from 10 to 2 min. Sonication was successful in dispersing bacterial clumps in both pure cultures and in raw milk samples to yield a bacterial count by DEFT which should give a better indication of the hygienic status and keeping quality of a product, than counts of colony forming units.
Molecular composition of Rhizobium meliloti when parathion was added at the start of incubation
Authors: Carranza M. M. , Rosas S. B. , Ghittoni N. E.
Published: March 2008

Rhizobium meliloti 300h13 reached the stationary phase of growth very quickly and died rapidly when parathion was added to broth medium at the start of incubation. After 120 h cells changed their molecular composition. A striking diminution in poly‐β‐hydroxybutyrate (PHB) accumulation was noticed, it was accompanied neither by increase of its glucan precursors, nor by increase of polysaccharides excretion. Parathion‐treated cells had decreased proteins, and augmented phospholipids (PL) and lipopolysaccharides (LPS) contents. The rise in PL was mainly due to increases in phosphatidyl glycerol (PG) and phosphatidyl choline (PC). LPS electrophoresis showed stacks of bands typical of LPS with increasing O‐antigen chain lengths. Bacterial fatty acids profiles showed an increase of cis‐vaccenic and palmitoleic acids, and a diminution of lactobacillic and palmitic acids.
Peroxide sensitivity of cold‐shocked Salmonella typhimurium and Escherichia coli and its relationship to minimal medium recovery
Authors: Mackey B. M. , Derrick Christine M.
Published: March 2008

Cold‐shocked Salmonella typhimurium displayed minimal medium recovery (MMR), viable counts on M9 minimal agar being much higher than those on tryptone soya yeast extract agar (TSYA). The addition of catalase to TSYA restored counts to the level found on M9 agar. Peroxide concentrations between 12 and 30 μmol/1 were measured in TSYB but none was detected in M9 medium. Cold‐shocked cells were sensitive to reagent hydrogen peroxide at a concentration similar to that found in TSYB. The minimal medium recovery phenomenon of cold‐shocked cells is thus a manifestation of peroxide sensitivity. Changing the composition of growth media affected both cellular catalase activity and the magnitude of the MMR effect but the two properties were not directly related. Factors additional to cellular catalase activity must therefore affect susceptibility to peroxide following cold shock. Muta tional loss of catalase, exonuclease III or recA‐dependent DNA repair functions all increased the sensitivity of cold‐shocked Escherichia coli to the inhibitory effects of peroxide present in rich medium. The peroxide resistant fraction of a cold‐shocked population of Salm. typhimurium (i.e. those cells able to grow on TSYA) was more resistant to gamma radiation than the population as a whole. Cold shock thus sensitizes cells to more than one form of oxidative stress. Prior exposure of growing cells to 30 μmol/1 hydrogen peroxide abolished their sensitivity to rich medium following cold shock implying that Salm. typhimurium contains an inducible system protecting against oxidative stress.
Role of selective pressure by screening organisms in the development of producer mutant isolates of different antibiotic markers
Authors: Basu S. , Das S. K. , Majumdar S. , Bhattacharyya D. , Bose S. K.
Published: March 2008

The phenotypes of producer mutant isolates when obtained after mutagenesis of the spontaneous degenerate Aspergillus versicolor N5 by screening on Trichophyton rubrum and those on A. niger G3Br were found to be markedly different. In respect of phenotypic character anti‐T. rubrum producer mutant isolates resembled the parental type more closely (which is specifically active against T. rubrum and generally against dermatophytes) than anti‐A. niger mutant isolates. This clearly indicates not only the role of selective pressure of the screening organism in the development of a given producer mutant isolate but also shows the possibility of recovery of a producer type of the lost antibiotic marker.
O‐Demethylation, dehydroxylation, ring‐reduction and cleavage of aromatic substrates by Enterobacteriaceae under anaerobic conditions
Authors: Grbic‐Galic D.
Published: March 2008

Four fermentative facultative anaerobes, members of the genera Enterobacter and Escherichia, were tested for their ability to transform an aromatic lignin derivative, 3‐methoxy‐4‐hydroxy‐cinnamic acid (ferulic acid), under anaerobic (fermentative) conditions. The pure cultures studied were shown to O‐demethylate, dehydroxylate, reduce the double bond in the side‐chain, decarboxylate the aromatic ring to the stage of benzoate and to reduce the ring to an alicyclic acid. Aromatic hydrocarbons (toluene, ethylbenzene and propylbenzene), as well as phenols (phenol, o‐cresol, p‐cresol, 2‐ethylphenol and 3‐hydroxy‐4‐ethylphenol) were also produced. In addition, during 3 months incubation, the cleavage of the aromatic ring occurred, whereby a small fraction of the substrate was converted to straight‐chain and branched (methylated, ethylated) five‐ to eight‐carbon aliphatic acids. The results indicate that pure cultures of fermentative facultative anaerobes might be capable of degrading substituted aromatic acids to aliphatic products under strictly anaerobic (fermentative) conditions. These abilities, which have so far been found only in denitrifying pseudomonads among facultative anaerobes, might be common in Enterobacteriaceae. It is conceivable that these bacteria are important as degraders of aromatic compounds in anaerobic ecosystems.