bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibiotics and the Oral Streptococci of Man
Authors: SUKCHOTIRATANA M. , LINTON A. H. , FLETCHER J. P. 
Published: March 2008

The effects of 3 antibiotics, phenoxymethylpenicillin, cephalexin and clindamycin on the normal oral streptococcal flora in the region of the gingival crevice were investigated because these organisms are able to cause subacute bacterial endocarditis. Secretion of these antibiotics into the oral cavity was also examined. Penicillin and clindamycin exerted marked effects on the normal oral streptococci, whereas cephalexin did not cause any obvious change in the total flora. Following penicillin therapy, streptococci resistant to 1.5 μg/ml penicillin were observed and these organisms could be detected at least 8 weeks after the last dose of the antibiotic. They probably arose by selection from the mixed flora. Following cephalexin therapy, a much lower proportion of streptococci resistant to 15 μg/ml was found. The proportion of resistant strains fluctuated appreciably, however, probably due to their transient nature. Streptococci resistant to 1 μg/ml clindamycin were not observed in 10 out of 11 treated subjects.Penicillin and clindamycin could be detected in the pooled saliva and gingival fluid after administering single doses of 500 mg and 300 mg, respectively. The peak levels were obtained between half and 1 h. The concentration of penicillin dropped rapidly within 3 h but clindamycin could be detected at significant levels for at least 6 h. No cephalexin could be detected in the pooled saliva or gingival fluid after a 500 mg dose. The implications of these findings in the prevention of subacute bacterial endocarditis are discussed.
Simple Equipment for the Growth of Photosynthetic Bacteria
Authors: STEVENS S. E. , FOX J. L. 
Published: March 2008

A simple temperature controlled growth facility for photosynthetic bacteria occupying 1 m2 of laboratory space is described.
Five types of growth vessels were compared in terms of cell doubling times and yields. The low form flask gave the best compromise for the large scale growth of photosynthetic bacteria.
Using six 3 21 low form flasks in this apparatus yielded 1 6 g dry wt 1‐1/day or 155 g dry wt cells/work week.
A Method for the Demonstration of Extracellular Hydrolysis of Poly‐β‐Hydroxybutyrate
Authors: MALIK K. A. , CLAUS D. 
Published: March 2008

A simple method has been developed for the rapid demonstration of extracellular hydrolysis of poly‐β‐hydroxybutyrate (PHB).
This is based on the use of thin PHB strips or films placed on inoculated mineral agar in Petri dishes or in liquid media.
It has been tested on various strains of different species of bacteria and the results showed complete agreement with the conventional overlayer method.
Preservation of Mycoplasmas on Anhydrous Silica Gel
Authors: THORNS C. J. 
Published: March 2008

1. 26 strains of mycoplasmas were successfully preserved on anhydrous silica gel crystals for 80 weeks at +4°C.2. There was a sharp decline in viability of the strains if they were stored at room temperature.3. This preservation technique is simple to perform and requires only inexpensive equipment.
Effect of Packaging under Carbon Dioxide, Nitrogen or Air on the Microbial Flora of Pork Stored at 4°C
Authors: ENFORS S.‐O. , MOLIN G. , TERNSTRÖM A. 
Published: March 2008

Changes in the microbial flora of pork packed in laminated plastic bags and stored at 4 °C were studied in an initial atmosphere of carbon dioxide, nitrogen or air. The time needed for the total aerobic count at 28 °C to reach 5 × 106 organisms/cm2 was about 7 times longer in carbon dioxide than in air, whilst in nitrogen it was about twice as long.The predominant organisms on fresh pork taken directly from the processing line were: Acinetobacter calcoaceticus, non‐fluorescent Pseudomonas spp. and Flavobacterium spp. After storage in air for 7 d, more than 90% of the flora consisted of non‐fluorescent Pseudomonas spp. After storage in nitrogen for 10 d, 70% of the flora consisted of non‐fluorescent Pseudomonas spp. with lower levels of fluorescent Pseudomonas spp., Kurthia zopfii, Aeromonas hydrophila and Lactobacillus plantarum. The non‐fluorescent Pseudomonas spp. could be divided into three different groups, on proteolytic and lipolytic ability; the distribution of the groups was markedly different between pork loins stored in air and nitrogen.On pork stored in carbon dioxide for 21 d the flora consisted of L. plantarum together with lower levels of heterofermentative lactic acid bacteria. When the storage time in carbon doxide was prolonged to 35 d, the proportion of heterofermentative lactic acid bacteria increased to about 50% of the flora.
Studies on Acid Tolerance of Rhizobium trifolii in Culture and Soil
Authors: BROMFIELD E. S. P. , JONES D. GARETH 
Published: March 2008

Several experiments were carried out in an attempt to isolate and adapt strains of Rhizobium trifolii to growth at low pH on citrate‐phosphate buffered yeast‐extract mannitol agar (CPYEM). In another experiment, two streptomycin resistant strains (7A strr and 16 strr) with contrasting tolerances to acidity in culture were evaluated for survival in acid upland soils.No acid tolerant clones were isolated from three strains on CPYEM suggesting that there were no cells with greater tolerance of low pH present. The stepwise subculture of several strains on media of decreasing pH also failed to increase their acid tolerance. Growth initiation on CPYEM at pH 4–4 was a function of the number of viable cells in the inoculum and was accompanied by a rise in pH.In three acid soils, strain 7A strr was more persistant than 16 strr, whereas in culture the converse was true. Survival of these strains in the acid soils was inversely related to acid production on the medium of Norris (1965) in agreement with Norris's hypothesis. Ameliorating soil pH with lime improved the persistency of both strains. Prior exposure of 7A strr and 16 strr to the acid soils failed to improve subsequent survival in these soils.
Relations of Selected Types of Micro‐organisms with the Vernal Phytoplankton Bloom in the Tvärminne Area, Southern Coast of Finland
Authors: VÄÄTÄNEN P. 
Published: March 2008

The fluctuations of selected types of micro‐organisms were considered in relation to the vernal phytoplankton bloom, consisting mainly of diatoms, in the Tvärminne area in March‐June 1978. Water samples were taken almost daily from the surface layer during the bloom, which comprised two biomass (chlorophyll a) peaks.Viable bacteria corresponded closely with the course of the bloom, the bacterial maxima occurring some days after the phytoplankton maximum. The bacteria apparently multiplied by mainly utilizing organic compounds released from decaying phytoplankton cells.Proteolytic bacteria had their maximum below the ice in the low‐salinity surface layer, but showed a positive correlation with the bloom. They evidently utilized proteins supplied by domestic effluents as well as those released from phytoplankton cells. Yeasts showed no distinct connection with the bloom; they were probably unable to compete for nutrients with bacteria. The low numbers of yeasts during the bloom can mainly be ascribed to the mixing occurring after the break‐up of the ice, which decreased the yeasts of terrestrial origin in the surface layer.
Growth of Bacteria on Meat at Room Temperatures
Authors: GILL C. O. , NEWTON K. G. 
Published: March 2008

The development of spoilage flora and the growth of individual psychrotrophs and pathogens on meat held at 20 or 30°C were studied. Under aerobic conditions psychrotrophic pseudomonads accounted for 60% of the spoilage flora at 20°C, but <20% at 30°C where they were displaced by species of Acinetobacter and Enterobacteriaceae which included both mesophilic and psychrotrophic strains. Mesophiles dominated the anaerobic spoilage flora at 30°C when clostridia were the major species, but at 20° the flora contained mesophiles and psychrotrophs in similar proportions and was dominated by Enterobacteriaceae. These results were largely predictable from the growth rate data for individual organisms.Interactions between species occurred more frequently at 20°C than at 30°C. When pathogenic species were grown at 20 or 30°Cin competition with equal numbers of psychrotrophic spoilage organisms, no interactions were observed. When pathogens were grown in competition with high numbers of psychrotrophs, only Lactobacillus growing anaerobically inhibited Salmonella typhimurium and Escherichia coli, but other pathogens were inhibited to varying degrees depending on the competing species and the incubation conditions. In general, the degree of inhibition was greater at 20 than at 30°C and facultative organisms were more susceptible under anaerobic than aerobic conditions. It appears that the cumulative stresses of low pH, suboptimal temperatures and competition with large numbers of saprophytic organisms can inhibit many of the pathogens likely to be present on meat. The organisms least affected by the conditions on meat surfaces, Salmonella and Esch. coli, are likely to be the main hazards on meat of normal pH held at room temperatures.
Spreading of Salmonellas during Cattle Slaughtering
Authors: STOLLE A. 
Published: March 2008

The spread of salmonellas during the slaughtering of cattle in the Berlin (West) slaughterhouse was investigated. The slaughterline was divided into 12 areas. During the first examination, which lasted eight months, the equipment and implements at each stage of slaughter, and faeces of cattle were tested. Salmonellas were not isolated from any of the 226 samples of faeces whereas 14 isolations (1.8%) were made from the 768 swabs taken from equipment. Most isolates were obtained within the step of opening the abdominal cavity.In a second survey 61 (4.3%) of 1392 swab samples and 2 (0.75%) of 267 faeces samples were positive. Of the different processing steps, cutting off the hooves and loosening the skin of legs gave the highest recovery of salmonellas. Moderate recoveries were obtained after opening the abdominal cavity. Removal of head, loosening the skin of head, removing the hide and splitting the breastbone and the carcass did not result in the isolation of the organism. Salmonella anatum was the most common isolate. The same serotypes were isolated from both carcasses and equipment.
Isolation and properties of psychrotrophic and psychrophilic, pectolytic strains of Clostridium
Authors: Brocklehurst T.F. , Lund Barbara M. 
Published: March 2008

AbstractFourteen strains of pectolytic clostridia have been isolated that were capable of growth at 5–10°C in 7 d; two strains were psychrophiles and failed to grow at 20°C in 14 d and the remainder were psychrotrophs. The bacteria formed pectate lyase enzymes and were capable of degrading potato tissue; they are therefore a potential cause of soft rot of potatoes stored at low temperatures. Doubling times for representative strains were 15–19 h at 10°C and 21–53 h at 5°C. Twelve strains were classified with Group I Clostridium species and two strains with Group II. In the case of one strain the mature spores were not released from the sporangium. Electron microscopy of ultrathin sections of this strain showed the presence of disorganized lamellar structures associated with the spore coat.
Influence of Clostridium saccharolyticum on cellulose degradation by Acetivibrio cellulolyticus*
Authors: Khan A.W. , Murray W.D. 
Published: March 2008

AbstractThe interrelationship between Acetivibrio cellulolyticus and Clostridium saccharolyticum, two anaerobes recently isolated from a methanogenic cellulose‐enriched culture, was studied in an examination of the role of saccharolytic anaerobes in habitats where cellulose is converted to methane. The presence of Cl. saccharolyticum decreased cellulose degradation by A. cellulolyticus as a result of substrate competition. Nevertheless A. cellulolyticus provided essential growth factor(s) and assimilable sugars including glucose which A. cellulolyticus itself does not utilize. Cl. saccharolyticum converted sugars to acetic acid and H2, known substrates for methanogens, and ethanol and lactic acid, known substrates for sulphate reducing bacteria. In natural habitats, the presence of both methanogens and sulphate reducing bacteria is essential for the existence of cellulolytic anaerobes.
An enzyme system hydrolysing the polysaccharides of Xanthomonas species
Authors: Sutherl I.W. 
Published: March 2008

AbstractEnzymes hydrolysing the exopolysaccharides of Xanthomonas campestris and related species (xanthan) have been obtained from a Bacillus species isolated by enrichment culture. Growth on xanthan induced a number of enzymes acting on the xanthan molecule. These included one or more β‐glucanohydrolases and β‐glucosidases, together with mannosidases. The former activities were also present in cultures grown in the presence of laminaran or scleroglucan, but not in simple synthetic media with glucose as substrate. Partial purification of the enzymes active on glucans was achieved by ammonium sulphate precipitation and chromatography on DEAE‐sepharose and CM‐sepharose. The specificity of the β‐glucosidase and the β‐glucanohydrolase were investigated. Several β‐glucans were hydrolysed to glucose and disaccharides, but there was no activity against β→ 6 linked polymers, cellulose azure or microcrystalline cellulose. Carboxymethylcellulose was hydrolysed, as were laminaran, scleroglucan and pachyman. Activity was greater against the β→ 4 linked glucans than against the β→ 3 linked glucans tested. As periodate‐oxidized laminarin was also hydrolysed, it was concluded that the glucanohydrolase acted as an endoenzyme. The β‐glucosidase had a pH optimum at about 8–2 and a temperature optimum at 45°C; it showed higher activity against o‐nitrophenyl‐D‐glucopyranoside, cellobiose, trehalose and sophorose than against gentibiose.
Genus Bacteroides A chemotaxonomical perspective
Authors: Shah H.N. , Collins M.D. 
Published: March 2008

1. Introduction, 4032. 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
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.
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.
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.
The infiltration ability of micro‐organisms Bacillus, Fusarium, Kluyveromyces and Pseudomonas spp. into xylem vessels of Gerbera cv. ‘Fleur’and Rosa cv. ‘Sonia’cut flowers: a scanning electron microscope study
Authors: Put Henriëtte M.C. , Clerkx Anke C.M. 
Published: March 2008

Scanning electron microscope (SEM) observations have been made of transverse and longitudinal sections of xylem vessels of cut flowers of Gerbera cv. ‘Fleur’and cut Rosa cv. ‘Sonia’after a maximum of 24 h vase life. Vase waters used were: sterile tap water; sterile tap water plus suspensions of single pure cultures of Bacillus polymyxa, B. subtilis, Fusarium oxysporum microspores, segments of young mycelium of F. oxysporum, Kluyveromyces marxianus, or Pseudomonas putida, up to a maximum of 106 and 5×107 cells/ml of vase water.The results of the SEM observations showed that only a small fraction of the microbial cells entered into the vascular system with the normal intake of vase water; most microbial cells remained attached to the submerged cut surface while a small fraction of the initially attached microbes were sometimes liberated into the surrounding vase water. The SEM figures give the impression that adhesion on to the cut stem surfaces of the bacterial cells (Bacillus and Pseudomonas spp.) by their capsular materials may have occurred, although the cut surface possibly acted as a filter, trapping cells because of the upward pressure of the transpiration stream into the vessels. Few attached yeast cells were found, but Fusarium microconidia formed cell clusters on the cut surface, partially blocking the xylem vessel entrance; Fusarium mycelium covered the cut‐surfaces as another filter layer through which only small mycelial particles could enter the vascular system.The extent of infiltration of microbial cells into the xylem vessel system depended upon the number of microbial cells/ml of vase water (up to a certain maximal number) and on the shape and size of the individual cells and the width of the xylem vessels. The end of the vase life of Gerbera and Rosa flowers was marked by an extensive water stress in the xylem vessels so that the water intake necessary for a normal flower development was insufficient and wilting ensued. The water deficit may have been enhanced by secondary biochemical and physiological interactions between the microbes and the plant tissues, which may also have affected the infiltration of micro‐organisms.
Methods used to investigate a possible environmental source of Mycobacterium avium‐intracellulare‐scrofulaceum (MAIS) infection in farmed deer
Authors: PROSSER B.A. 
Published: March 2008

Currently used methods for the culture of mycobacteria from contaminated material were found to be unsatisfactory in an investigation of a possible environmental source of Mycobacterium avium‐intracellulare‐scrofulaceum (MAIS) infection in a New Zealand deer farm. Different combinations of established procedures were investigated using soil spiked with a laboratory strain of M. avium.The most successful combination involved mixing the soil in nutrient broth (pH 8mD0) containing Tween 80, incubating at 37°C for 1 h to germinate sporing contaminants, treatment for 24 h with 1% cetylpyridinium chloride, followed by washing and culture on Lowenstein‐Jensen slopes and incubation at 37°C and 42°C in approximately 5% CO2 atmosphere. This procedure allowed good recovery of M. avium while successfully inhibiting saprophytic mycobacteria and other soil organisms, and was chosen to process the deer farm samples. No mycobacteria resembling the deer strains were found in these samples.