bluuebunny/crossref_metadata_2025 huggingface dataset:
The in vitro uptake and metabolism of peptides and amino acids by five species of rumen bacteria
Authors: Ling J.R. , Armstead I.P.
Published: March 2008

J. R. LING AND I.P. ARMSTEAD. 1995. Streptococcus bovis JB1, Prevotella ruminicola B1 4, Selenomonas ruminantium Z108, Fibrobacter succinogenes S85 and Anaerovibrio lipolytica 5S were incubated with either 14C‐peptides (mol. wt, 200–1000) or 14C‐amino acids to compare their rates of uptake and metabolism. In experiment 1, the bacteria were grown and incubated in a complex medium, but no uptake of 14C‐labelled substrates occurred. When casein digest was omitted, uptake rates of 14C‐peptides were different (P < 0·01) with each species, but nil for 14C‐amino acids. In experiment 2, to minimize the effects of non‐radiolabelled peptides and amino acids, defined and semi‐defined media were used. Patterns of 14C‐peptide uptake resembled those of experiment 1. The 5‐min rate for Strep. bovis JB1 was almost twice that of P. ruminicola B14, though by 15 min they were similar and threefold greater than other species; that of A. lipolytica 5S was especially low. Incubations with 14C‐amino acids resulted in a wide range (P < 0·01) of uptake rates; after 5 min P. ruminicola B14 possessed the lowest and Strep. bovis JB1 the highest, but after 15 min, that of Sel. ruminantium Z108 was even higher. All bacteria, with the exception of P. ruminicola B14, assimilated 14C‐amino acids faster (P < 0·01) than 14C‐peptides. Only Strep. bovis JB1 and P. ruminicola B14 were capable of extensively metabolizing 14C‐peptides, but all five species metabolized 14C‐amino acids; there was evidence of substantial degradation and some synthesis. Calculations suggest that peptides could supply up to 43%, and amino acids 62% of the N requirements of rumen bacteria.
Identification of two α‐glucosidase activities in Clostridium acetobutylicum NCIB 8052
Authors: Albasheri K.A. , Mitchell W.J.
Published: March 2008

K.A. ALBASHERI AND W.J. MITCHELL. 1995. Maltose metabolism in the obligate anaerobe Clostridium acetobutylicum was studied. The sugar is accumulated via an energy‐dependent transport process which is not a phosphotransferase. Cell extracts were incapable of phosphorylating maltose in the presence or absence of phosphoenolpyruvate or ATP, but exhibited hydrolytic activity against a range of glucoside substrates. The activity was predominantly in the soluble fraction of cell extracts, indicating a cytoplasmic location in the cell. Gel filtration on Sephadex G100 indicated the presence of at least two α‐glucosidases. One enzyme (maltase) was active with maltose and maltotriose, while the other (pNPGase) hydrolysed isomaltose and several glucoside analogues, but neither showed activity against starch. Both glucosidases were induced by isomaltose, maltose, glucose and starch, but not by xylose, sucrose or cellobiose. In the presence of both glucose and maltose, growing cells showed a preference for glucose, apparently due to regulation of maltose transport, which did not occur in glucose‐grown cells.
Exopolysaccharide production by Bifidobacterium longum BB‐79
Authors: Roberts Cynthia M. , Fett W.F. , Osman S.F. , Wijey C. , O'Connor J.V. , Hoover D.G.
Published: March 2008

Bifidobacterium longum BB‐79 produced an acidic extracellular polysaccharide (EPS), especially when grown on solid medium. The EPS was isolated by ethanol precipitation followed by dialysis and lyophilization. Anion exchange and gel‐filtration chromatography were used to further purify and characterize the EPS. The average molecular weight was greater than 200 kDa as estimated by chromatography. Based on gas‐liquid chromatography (GLC) and GLC‐mass spectrometry analyses, the EPS appears to be composed of galactose and an unidentified hexose (possibly glucose) with a carboxyethyl (lactic acid) substituent. Lactose, when used as the primary carbon source in liquid media, gave the highest yield of EPS. Incubation times longer than 24 h and the initial culture pH (pH 6·0–9·0) had little effect on the amount of EPS produced.
Relationship of combined nitrogen sources to salt tolerance in freshwater cyanobacterium Anabaena doliolum
Authors: Rai Ashwani K. , Abraham G.
Published: March 2008

Higher concentrations of NaCl inhibit the growth and reduce the specific growth rate of the freshwater cyanobacterium Anabaena doliolum. Among the nitrogen sources tried, nitrate protected the cyanobacterial cells most from salt toxicity. However, supplementing of medium with nitrate could increase the adaptability of the cells at sublethal doses but it would not permit growth at otherwise lethal doses of 300 mmol 1‐1 NaCl. Nitrate uptake was proportionally related to the NaCl level in the medium. The uptake of sodium was minimum when nitrate was simultaneously available to the cells, indicating the interaction of nitrate with the Na+ carrier. Na+ efflux was maximum in N2, ammonia, urea and nitrate in decreasing order. This led to the conclusion that Na+ influx plays the critical role in salt tolerance, rather than its efflux.
Detection of Yersinia enterocolitica O:3 in faecal samples and tonsil swabs from pigs using IMS and PCR
Authors: Rasmussen H.N. , Rasmussen O.F. , Christensen H. , Olsen J.E.
Published: March 2008

Dilutions of faecal samples spiked with Yersinia enterocolitica O:3 were analysed using immunomagnetic separation (IMS) followed by PCR. In 10% faecal dilutions with added Y. enterocolitica cells; the limit of detection was 200 cells g‐1 faeces. Faecal samples from 38 pigs were analysed by IMS‐PCR in parallel with detection and quantification of Y. enterocolitica O:3 using cold pre‐enrichment culturing. Of the 15 culture‐positive samples, only two were detected with IMS‐PCR. These two samples contained 40–400 Y. enterocolitica O:3 cells g‐1 faeces; the highest level found in the investigation. This indicated that the low sensitivity of IMS‐PCR was due to low amounts of cells in the faecal samples. Swab samples from 195 pig tonsils, taken on a slaughterline were examined using IMS‐PCR and culture detection. Of 164 culture‐positive samples, 60 were positive with IMS‐PCR. In addition, IMS‐PCR was positive for three culture‐negative samples. Forty‐five of the samples were further examined by IMS‐PCR after 7–10 d of cold pre‐enrichment. All 31 culture‐positive samples as well as five culture‐negative samples were detected by IMS‐PCR. From these data it can be concluded that IMS‐PCR can be used to detect Y. enterocolitica O:3 cells after pre‐enrichment, but direct detection needs further optimization of the sample preparation procedures.
Isolation and properties of free and immobilized β‐galactosidase from the psychrotrophic enterobacterium Buttiauxella agrestis (strain NC4)
Authors: Amarita F. , Alkorta F. , du Plessix M. Lescan , Cantabrana T. , Rodriguez‐Fernandez C.
Published: March 2008

A study of the β‐galactosidase produced by the psychrotrophic bacterium Buttiauxella agrestis has been carried out. This micro‐organism was isolated from raw milk and the enzyme isolated using standard methods. Molecular mass was estimated to be 515 kDa. The isoelectric point was close to 4·45. Optimum pH was 7·25. Maximal activity was observed at 50°C and activation energy was estimated to be 39·1 kJ mol‐1. Lactose enhanced thermal stability. Using α‐nitrophenyl‐β‐D‐galactopyranoside as the substrate, the Km was 11 μmol 1‐1 and Vmax was 85 U mg‐1 protein. β‐Mercaptoethanol and ethanol were inhibitors; glycerol acted as a complex effector. The enzyme required divalent cations for activity while it was inhibited by EDTA. When the enzyme was immobilized in diethyl aminoethylcellulose the optimum pH of activity was 8. Km was 47 μmol 1‐1 and Vmax was 96 U mg‐1 protein.
Plasmid formation and its relation to the formation of spontaneously developing pocks in Streptomyces azureus ATCC 14921
Authors: Doi K. , Saeki M.C. , Ono Y. , Ogata S.
Published: March 2008

Streptomyces azureus ATCC 14921 harboured a plasmid pSA1 together with its chromosomal integrated sequence (pSA1int). The att P site on the plasmid was located at ca 170 bp BamHI‐SphI fragment by site‐specific integration. The free form was generated from the integrated sequence during the development of its host mycelia in the solid culture, but not in the liquid culture. The free form seemed to elicit the formation of spontaneously developing pocks on its host mycelia in the solid culture.
Quality control of membrane filters for bacteriological examination of water
Authors: Schijven J.F. , Drost Y.C. , Castelijns H. , van der List C.
Published: March 2008

A standard protocol for quality control of membrane filters for bacteriological examination of water is presented. It is based on the screening test proposed by Brenner and Rankin (1990) making use of Enterobacter aerogenes ATCC 49701 as a test strain and tryptone soya agar as medium for incubation. The protocol is standardized to achieve adequate statistical power. A diluted culture of the test strain is filtered through samples of 20 filters of a test batch and a reference batch. Filters and colony morphology are screened for visual defects and criteria for acceptance are given. Variation in the colony counts within the batches is checked for randomness, because filters of a batch must be of equal quality and must not cause overdispersion. The protocol requires that the mean count of the reference batch should lie between 50 and 80 cfu. Homogeneity of the counts (i.e. variation no greater than random) between the batches is tested at a 99% confidence level. In this way an actual difference in recovery between filter batches of 13% to 16% can be detected with a probability of 90%. Results of several tests within this laboratory show good reproducibility.
Selenium and Lactobacillus species
Authors: Calomme M. R. , Van den Branden K. , Vanden Berghe D.A.
Published: March 2008

Selenium (Se) is an essential element for man and animal. Supplementation of Se has been done with Se‐enriched yeast and inorganic Se compounds. In the present study a quantitative and qualitative evaluation was made of whether lactobacilli are able to concentrate Se. A high correlation was found between the bacterial Se concentration and the concentration of Se in the medium. The Se concentration in biomass was respectively 253 ± 50, 375 ± 33 and 407 ± 108 μg g−1 dry weight for Lactobacillus delbrueckii subsp. bulgaricus, Lact. plantarum and Lact. casei subsp. casei when 1 mg 1−1 Se4+ was present in the medium. Manganese (Mn) was concentrated in Lact. plantarum and Lact. casei subsp. casei but not in Lact. delbrueckii subsp. bulgaricus. The Mn concentration in biomass was higher compared to the Se concentration but this difference decreased when the concentration of Mn/Se increased in the culture medium. Copper, zinc and iron were also concentrated in biomass of Lact. delbrueckii subsp. bulgaricus. Characterization of the bacterial selenocompound revealed that 75Se was generally incorporated, as selenocysteine, into protein of Lact. delbrueckii subsp. bulgaricus. Addition of L‐cysteine to the medium decreased the bacterial Se content. It was concluded that Lact. delbrueckii subsp. bulgaricus incorporated Se non‐specifically into bacterial protein. The application of Se‐enriched lactobacilli (Se‐Lb) in Se supplementation would be an interesting approach since selenomethionine, which is the major selenocompound in commercialized Se‐yeast, was not detected in Se‐Lb and because lactobacilli are already widely used in human nutrition.
The effect of sodium chloride concentration and pH on the growth of Salmonella typhimurium colonies on solid medium
Authors: McKay A.L. , Peters A.C.
Published: March 2008

The growth of Salmonella typhimurium colonies on a model food system (agar solidified culture medium) was followed. Colony radius, determined using computer image analysis (IA) techniques, and viable cell number per colony were measured as indices of colony growth, and the effect of [NaCl] (0.5–3.5% (w/v)) and pH (7.0–5.0) on colony growth at 30°C was observed; colonies were point inoculated from serial dilutions. Colony growth (between 13 and 26 h after inoculation) was linear when expressed in terms of radius, and exponential when expressed in terms of viable cell number per colony. Overall, both increasing the [NaCl] and decreasing the pH had little effect on colony growth, other than to delay the onset of linear radial growth. Initial specific growth rate (μ) ranged from 0.73 to 0.87 h−1. Thin films of agar medium on microscope slides allowed the growth of microcolonies to be observed after just 4 h incubation. A greater understanding of the growth kinetics of bacterial colonies, and the effects of environment on such data, may enable better control of foodborne bacterial pathogens, and consequently an improvement in food product safety.
Rapid assessment of physiological status inEscherichia coliusing fluorescent probes
Authors: Porter J. , Edwards C. , Pickup R.W.
Published: March 2008

Rapid and direct viability assessment ofEscherichia coliin filtered, sterile lake water was possible using multiparameter flow cytometry. Fluorescent dyes were used as probes for different cellular functions (membrane potential, membrane integrity and intracellular enzyme activity), which were correlated with the ability of the cells to respond to nutrient addition while in a stressed state. Measurement of several criteria circumvented limitations imposed by other methods, and provided extensive evidence for the validity of the methods for monitoring cell viability during adoption of a viable‐but‐non‐culturable state in starvedE, coli.Macromolecular staining was concomitantly used to monitor changes in cellular protein, RNA and DNA as additional indicators of physiological status during starvation/stress.
Activity of plantaricin SA6, a bacteriocin produced by Lactobacillus plantarum SA6 isolated from fermented sausage
Authors: Rekhif N. , Atrih A. , Lefebvrexy G.
Published: March 2008

N. REKHIF, A ATRIH AND G. LEFEBVRE. 1995. Plantaricin SA6, a bacteriocin produced by Lactobacillus plantarum SA6, exhibited an inhibitory action against several mesophilic lactobacilli. It was stable at 90–100°C at pH 2–4 and it remained stable in the presence of several organic solvents, urea or β‐mercaptoethanol. Plantaricin SA6 bound specifically to the cell surface of only plantaricin SA6‐sensitive bacteria. The putative receptors are not destroyed by different hydrolytic enzymes added to the phosphate buffer. Plantaricin SA6 acted as a bactericidal agent lysing sensitive strains, that became more permeable to ortho‐nitro‐phenol‐β‐galactoside and lost their intracellular K+ ions and u.v.‐absorbing materials. Both the adsorption and lethal action of plantaricin SA6 were maximal between pH 4 and 7, but the range of temperature tested (5–37βC) had no effect. Ions (of several salts such as MgCl2) inhibited the binding of plantaricin SA6 and protected cells against bacteriocin action.
Evaluation of enrichment broths for their ability to recover heat‐injured Listeria monocytogenes
Authors: Patel J.R. , Beuchat L.R.
Published: March 2008

J.R. PATEL AND L.R. BEUCHAT. 1995. Listeria selective enrichment broth (LEB), University of Vermont (UVM) broth, modified UVM (MUVM) broth and Fraser broth (FB) were compared for their ability to recover cells of L. monocytogenes from heated tryptose phosphate broth. Three strains of L. monocytogenes were heated at 54C for 30 min, inoculated into enrichment broths supplemented with 400 µg catalase ml−1, and incubated for 8 h at 30°C. After incubation for 4 h, the total viable cell populations either decreased or did not change, whereas the number of healthy (non‐injured) cells of all strains increased significantly in all broths except FB inoculated with the LCDC strain. With an increase in incubation time to 8 h, the number of healthy cells of all strains increased in all broths. At 8 h, the difference between populations of total (injured plus healthy cells) and healthy cells detected in LEB inoculated with two strains was not significant. Overall, recovery of heat‐treated cells was significantly higher in LEB, followed by MUVM broth, UVM broth and FB. The addition of catalase to enrichment broths significantly enhanced recovery of heat‐injured cells. A slight reduction of catalase activity of heated cells of all test strains in all enrichment broths except FB was observed by extending the incubation period from 4 to 8 h. A test strain that produces relatively higher catalase activity compared to the other strains exhibited the greatest resistance to exogenous hydrogen peroxide. Enumeration of viable L. monocytogenes cells in heated foods should be done using LEB supplemented with 400 µg catalase ml−1 to maximize the recovery of injured cells.
Possible interference of lactose‐fermenting marine vibrios in coliform ‐D‐galactosidase assays
Authors: Davies Cheryl M. , Apte S.C. , Peterson Sharon M.
Published: March 2008

C.M. DAVIES, S.C. APTE AND S.M. PETERSON. 1995. An investigation into possible interferences in β‐D‐galactosidase‐based assays for coliform bacteria in marine waters was carried out. A rapid instrumental fluorescence assay for β‐D‐galactosidase activity, using 4‐methylumbelliferyl‐β‐D‐galactosidase as a substrate, was used to investigate activities of this enzyme in non‐coliform bacterial isolates from coastal waters. Only 2% of isolates showed slight enzyme activity after a 1‐h incubation period at 44.5βC. At a lower incubation temperature of 20βC, 51% and 94% of the isolates showed some enzyme activity within 6 h and 48 h, respectively. Fifty‐nine out of 67 of these isolates were identified as Vibrio species. A lac+ strain of Vibrio vulnificus was found to produce β‐D‐galactosidase which caused significant false‐positive reactions in the Colilert‐Marine Water assay when present at concentrations of 10 cfu ml−1 or greater. This interference could be overcome by addition of the vibriostatic agent O/129. The high fluorescence of this reagent, however, precluded the simultaneous determination of Escherichia coli in the Colilert test and also its use in instrumental fluorescence assays. It was concluded that in assays employing high temperatures and short incubation times, Vibrio species are unlikely to cause significant interferences.
Antibacterial effect of protamine assayed by impedimetry
Authors: Johansen Charlotte , Gill T. , Gram L.
Published: March 2008

Impedimetric measurements were used to assay the antibacterial effect of protamine. A good linear correlation between the impedance detection time and the initial cell counts was obtained (r= 0.99, n= 2). As basic peptides may cause clumping of cells, this correlation curve was used when estimating the cell number after protamine treatment, rather than colony counts.

Protamine from salmon killed growing Gram‐positive bacteria and significantly inhibited growth of Gram‐negative bacteria in Tryptone Soy Broth (TSB) at 25°C. In general Gram‐positive bacteria were more sensitive to protamine than Gram‐negative bacteria; the minimum inhibitory concentrations (MIC) determined for Gram‐positive strains varied from 20 to 1000 μ ml‐1 and for Gram‐negative strains from 500 μ ml‐1 to more than 4000 μ ml‐1.

The effect of protamine on non‐growing Listeria monocytogenes Scott A suspended in buffer was not lethal as was the effect on growing cells; however, protamine (50–500 μg ml‐1) killed the Gram‐negative fish spoilage bacteria Shewanella putrefaciens when the live cells were suspended in buffer.
Purification and characterization of a component produced by Lactobacillus fermentum that inhibits the adhesion of K88 expressing Escherichia coli to porcine ileal mucus
Authors: Ouwehand A.C. , Conway P.L.
Published: March 2008

It has previously been shown that Lactobacillus fermentum strain 104r releases compounds into its culture fluid that inhibit the adhesion of enterotoxigenic Escherichia coli K88. The aim of the present study was to purify and identify this compound. Judged by gel filtration, the compound was found to be approximately 1700 kDa. The amount of active compound increased upon prolonged incubation, while the number of viable cells reduced, suggesting that the activity was coming from dead cells. As the activity can be destroyed by lysozyme treatment and contains glucose, N‐acetylglucosamine and galactose, it was concluded that cell wall fragments are the active agent, although cell wall preparations did not have the same effect. Adhesion to some mucus fractions could be inhibited by spent culture fluid, indicating specific interaction between mucus and the active compound. The compound was not able to interfere with the adhesion of E. coli 1107 to neutral lipids from mucus which contain a glycolipid receptor for K88 fimbriae.
Effects of culture conditions on Pectinatus cerevisiiphilus and Pectinatus frisingensis metabolism: a physiological and statistical approach
Authors: Tholozan J.‐L. , Membré J.‐M. , Kubaczka M.
Published: March 2008

The genus Pectinatus has been often reported in beer spoilage with off‐flavours. The bacteria are strictly anaerobic, Gram‐negative rods. Propionate and acetate are the main fermentation products from glucose in the two species belonging to the genus, P. cerevisiiphilus and P. frisingensis. Amino acids routinely present at a high level in beer were not growth substrates for both species, and a significant accumulation of succinate was observed with lactate as growth substrate. Both Pectinatus ssp. showed almost identical fermentation balances on glucose. Growth kinetics of both glucose‐grown species were unchanged under a N2, H2 or 20% CO2‐containing atmosphere. Combinations of culture medium pH values from pH 3·9 to pH 7·2, of glucose levels between 5 and 55 mmol l‐1, and of lactate concentrations varied from 4 to 40 mmol l‐1 demonstrated that biomass and volatile fatty acids production were proportional to glucose concentration for both Pectinatus species. A significant increase of volatile fatty acid production was measured for both species at the lowest pH values with a lactate or a glucose concentration increase. The maximum biomass production was observed at pH 6·2 for P. cerevisiiphilus, and between pH 4·5 and pH 4·9 for P. frisingensis. Glucose and lactate or pH value were dependent with regard to propionate and acetate production in P. frisingensis. On the other hand, the variations of these three parameters were independent with regard to biomass production for both strains, and to volatile fatty acids production for P. cerevisiiphilus. Addition of ethanol to glucose‐grown cultures completely inhibited growth at 1·3 mol l‐1 ethanol for P. cerevisiiphilus, and at 1·8 mol l‐1 for P. frisingensis.
Damage to Pseudomonas aeruginosa PAO1 bacteriophage F116 DNA by biocides
Authors: Maillard J.‐Y. , Beggs T.S. , Day M.J. , Hudson R. A. , Russell A.D.
Published: March 2008

The mechanism of action of biocides against viruses has not been widely studied, although two main targets are viral proteins (capsids, enzymes) and the viral genome. This study was undertaken in order to investigate the efficacy of several disinfectants against the nucleic acid of the Pseudomonas aeruginosa PAO bacteriophage F116. Of all the biocides tested, only peracetic acid affected significantly the phage genome. However, it is not clear whether the nucleic acid was damaged inside the phage capsid or when released into the surrounding medium.
Development of a predictive model for growth of Listeria monocytogenes in a skim milk medium and validation studies in a range of dairy products
Authors: Murphy P. M. , Rea M. C. , Harrington O.
Published: March 2008

A predictive model based on growth of Listeria monocytogenes in milk is described. The main aim of this work was to generate a predictive model in milk acidified with lactic acid to mimic conditions found in a range of dairy products. A complete factorial design was employed to determine the effects of pH (4·5‐7·5), temperature (3·35°C) and salt concentration (0‐8%) on growth of the organism. There were 210 design points and growth curves were individually fitted for the Gompertz function using non‐linear regression. Descriptors of the curves, such as lag phase duration (LPD), exponential growth rate (EGR) and generation time (GT) were calculated and polynomial models were developed relating these to pH, temperature and salt concentration. The selected cubic polynomial model gave acceptable predictive estimates of growth and was stable, i.e. predictions were repeatable over the range of environmental variables studied. The model was further tested to determine its capacity for predicting growth of listeria in a range of dairy foods and these validation studies confirm its usefulness as a rapid means for estimating growth of the organism under specified environmental conditions.
Pediocin 5 production and plasmid stability during continuous free and immobilized cell cultures of Pediococcus acidilactici UL5
Authors: Huang J. , Lacroix C. , Daba H. , Simard R.E.
Published: March 2008

Continuous production of pediocin 5 from Pediococcus acidilactici UL5 was investigated in MRS medium at different pH and dilution rates during continuous free cell (FC) and immobilized cell (IC) fermentations. Pediocin 5 activity from FC operated at a dilution rate of 0·31 h−1 largely increased from 128 to 2048 AU ml−1 as pH decreased from 7·0 to 5·0. Pediocin 5 activity in IC at a dilution rate of 0·93 h−1 was much less affected by pH, varying from 256 AU ml−1 at pH 7·0 to 512 AU ml−1 at pH 5·0. At the optimum pH 5·0, the dilution rate greatly influenced pediocin 5 activity both in FC and IC. Pediocin 5 production during continuous FC culture decreased with time for all dilution rates tested except 0·31 h−1 and average activity over 144 h cultures reached a maximal value of 4915 AU ml−1 at a dilution rate of 0·26 h−1. For IC, pediocin 5 production was stable with time and increased with the dilution rate from 256 to 1024 AU ml−1 in the range of 0·47‐2·28 h−1. Three Listeria strains were tested for their ability to screen low bacteriocin‐producing variants (Bacv+) of Bac+ cells in FC and IC cultures by using a modified deferred antagonism method. Ten to 28% of Bacv+ cells appeared after 144 h of FC cultures at dilution rates in the range 0·09‐0·42 h−1 and pH control set points of 5·0‐7·0 while almost no Bacv+ cell was detected during 192 h IC culture in the same pH range and for dilution rates varying from 0·47 to 2·28 h−1. The Bacv+ cells isolated produced eight‐ to 64‐fold less pediocin 5 than the Bac+ cells. Although electrophoresis analysis showed no apparent difference in the plasmid profiles of Bacv+ and Bac+ cells, the Bac− mutant obtained by acriflavine treatment had lost the pMJ5 plasmid encoding for bacteriocin production. The decreased quantity of plasmid DNA in Bacv+ cells suggests that the decreased pediocin 5 activity of Bacv+ cells resulted from a decrease in plasmid copy number.
Influence of 1,10‐phenanthroline and its analogues, other chelators and transition metal ions on dipeptidase activity of the rumen bacterium, Prevotella ruminicola
Authors: Wallace R.J. , McKain N.
Published: March 2008

Prevotella ruminicola plays a prominent role in the breakdown of peptides in the rumen, a process which contributes to excessive ammonia production and inefficient nitrogen retention in ruminants. Various metal ions and chelators were examined to assess how the metal ion‐dependent dipeptidase activity of P. ruminicola M384 might be inhibited. Using sonicated extracts, Cu2+, Cr2+ and Hg2+ were most inhibitory, decreasing Ala2 breakdown to 15, 15 and 5% of control activity, whereas Co2+, Mn2+ and Zn2+ stimulated activity by 189, 30 and 26%, respectively. The chelators, EDTA, EGTA, TPEN and 1,10‐phenanthroline, were inhibitory, as were several phenanthroline analogues. Among the stereoisomers of 1,10‐phenanthroline tested, derivatives methylated on C‐2 and C‐9 were less effective than the parent molecule, but 3,4,7,8‐tetramethyl,10‐phenanthroline (TMP) was more inhibitory. Titration of the most effective inhibitors showed that EDTA, TPEN and TMP had similar potency and were effective at 0.1 mmol l−1 and above. Thus some metal ions and chelators are potent inhibitors of P. ruminicola dipeptidase, although they are unlikely to be sufficiently specific to peptide metabolism to be useful in vivo.
Partial characterization of an inhibitory strain of Erwinia herbicola with potential as a biocontrol agent for Erwinia amylovora, the fire blight pathogen
Authors: Kearns L.P. , Hale C.N.
Published: March 2008

Erwinia herbicola Eh1087 isolated from apple blossom inhibits development of Erwinia amylovora in immature pear fruit and produces a broad spectrum antibiotic activity in vitro that is bactericidal for Erw. amylovora. The antibiotic activity is present in cell‐free culture supernatant fluids of late log‐early stationary phase cultures of Eh1087. This antibiotic activity is not inhibited by proteases, excess ferric ions or essential amino acids. It is stable to acidic and basic pH and is inactivated at high temperature. The antibiotic activity is inactivated by β‐lactamase digestion.
A probability matrix for the identification of campylobacters, helicobacters and allied taxa
Authors: On S.L.W. , Holmes B. , Sackin M.J.
Published: March 2008

A probabilistic identification matrix for campylobacteria, comprising 67 phenotypic characters and 37 taxa, is described. The accuracy and integrity of the matrix was evaluated using established computer‐assisted methods. Certain taxa (for example, Campylobacter concisus and Camp. gracilis) demonstrated significant phenotypic diversity; previous data corroborated these findings. Differentiation between a few pairs of taxa proved difficult, although discriminatory characteristics were noted in each of these cases. The results indicate that most campylobacteria can be identified accurately and objectively with phenotypic tests when probabilistic methods of data assessment are employed.
Random amplification of polymorphic DNA (RAPD) of Salmonella: strain differentiation and characterization of amplified sequences
Authors: Hilton A.C. , Banks J.G. , Penn C.W.
Published: March 2008

Random amplification of polymorphic DNA (RAPD) was evaluated for its ability to differentiate Salmonella strains from various sources. Under defined conditions RAPD using a 10‐mer primer (1254) produced a series of amplification products able to reproducibly distinguish strains representing 20 different serotypes of Salmonella. Primer 1254 also proved capable of discrimination between some but not all isolates of Salm. ser. Enteritidis and Salm. ser. Typhimurium, phage typing proving to be most discriminatory for the latter serotype. Cloning of fragments into a vector allowed sequencing and database searching for identification of fragments and an indication of criteria for primer template interaction in RAPD. Southern blotting using a digoxigenin‐labelled probe allowed identification of related bands between RAPD profiles. These observations demonstrate the potential of rapid molecular typing by RAPD for the genomic typing of Salmonella strains.
Note: Influence of hydrocarbons on some Claviceps cultures
Authors: Gil'manov V. , Flieger M. , Dymshits V.
Published: March 2008

Some Claviceps strains producing clavine alkaloids were cultured in shaken flasks in two‐phase systems consisting of a water‐immiscible organic solvent, n‐alkanes and an aqueous culture medium. Culture behaviour was different with light and heavy alkanes but no changes in the proportions of individual alkaloids were found. n‐Octane caused a stimulation of sclerotia‐like growth and of specific biomass productivity. Increasing medium volumes in flasks brought about deterioration of aeration conditions and reduced production. Optimum fermentation results were restored by adding liquid paraffin to the culture. Heterogeneous systems of the above kinds appear to be suitable for optimization and scale‐up of clavine fermentation.
Effect of Saccharomyces boulardii against experimental oral infection with Salmonella typhimurium and Shigella flexneri in conventional and gnotobiotic mice
Authors: Rodrigues A.C.P. , Nardi R.M. , Bambirra E.A. , Vieira E.C. , Nicoli J.R.
Published: March 2008

A.C.P. RODRIGUES, R.M. NARDI, E.A. BAMBIRRA, E.C. VIEIRA AND J.R. NICOLI. 1996. Saccharomyces boulardii was shown to be capable of inhibiting multiplication of enteropathogenic bacteria in vitro and is currently used for its anti‐diarrhoea properties. We studied the capacity of this yeast to antagonize Salmonella typhimurium and Shigella flexneri in the intestinal tract of conventional or gnotobiotic NMRI mice. Conventional animals were given daily 10 mg doses of S. boulardii, whereas germ‐free animals were given a single 10 mg dose. Both groups were challenged orally 5 d later with the pathogenic bacteria (108 or 102 viable cells, respectively). Control groups were treated with saline instead of S. boulardii. Mortality and/or histopathological data showed a protective effect against the pathogenic bacteria in yeast‐treated mice. Saccharomyces boulardii colonized the digestive tract of gnotobiotic mice and the number of viable cells ranged around 1010 g‐1 of faeces. In experimental and control gnotobiotic animals, Salm. typhimurium and Sh. flexneri became rapidly established at a level of about 1010 viable cells g‐1 of faeces and remained at high levels until the animals died or were sacrificed. The protection against Salm. typhimurium and Sh. flexneri obtained in conventional and/or gnotobiotic mice previously associated with S. boulardii is not due to the reduction of the bacterial populations in the intestines.
Enumeration of human colonic bacteria producing phenolic and indolic compounds: effects of pH, carbohydrate availability and retention time on dissimilatory aromatic amino acid metabolism
Authors: Smith E.A. , Macfarlane G.T.
Published: March 2008

E.A. SMITH AND G.T. MACFARLANE. 1996. Concentrations of phenolic compounds in human gut contents were more than fourfold higher in the distal colon (6.2 mmol kg‐1) compared to the proximal bowel (1.4 mmol kg‐1). Tryptophan metabolites were never found in more than trace amounts in large intestinal contents and phenol substituted fatty acids were the major products of aromatic amino acid fermentation that accumulated in the proximal colon, whereas phenol and p‐cresol were more important in the distal gut, accounting for 70% of all products of dissimilatory aromatic amino acid metabolism. In vitro incubations of colonic material showed that phenol was produced most rapidly (1.0 μmol g‐1 h‐1), whereas indole was formed comparatively slowly (0.06 μmol g‐1 h‐1). Most probable number (MPN) estimations demonstrated that large populations of phenol and indole producing bacteria occur in the large intestine (range log10 9.8–11.5 (g dry wt faeces)‐1, mean 10.6, N=7). With respect to phenolic compounds, phenylacetate and phenylpropionate producers predominated, while indoleacetate‐forming bacteria were the major tryptophan‐utilizing organisms. Quantitation of products of dissimilatory aromatic amino acid metabolism in MPN tubes showed that phenol and phenylpropionate mainly accumulated at low sample dilutions, whereas phenylacetate, p‐cresol, indoleacetate and indolepropionate were formed in greatest amounts at high sample dilutions. The significance of pH and carbohydrate availability with respect to aromatic amino acid metabolism was shown in batch culture fermentation studies, where net production of phenolic compounds by mixed populations of intestinal bacteria was reduced by approximately 33% during growth at pH 5.5 compared to pH 6.8, and by 60% in the presence of a fermentable carbohydrate. Experiments with 16 species of intestinal bacteria belonging to six different genera showed that environmental factors such as low pH and high carbohydrate availability markedly reduced dissimilatory aromatic amino acid metabolism in some organisms, but stimulated this process in others. A three‐stage continuous culture model of the colon was used to investigate the effect of system retention time (27.1 or 66.7 h) on aromatic amino acid fermentation. Qualitative and quantitative increases in phenol production occurred from vessel 1 to vessel 3 in this model. Concentrations of phenolic compounds in vessel 3 were three times greater at R=66.7 h compared to R=27.1 h. Phenol and p‐cresol were not detected in vessel 1, though formation of these metabolites increased from vessel 2 to vessel 3, in a pattern similar to that observed in the distal colon.
Development of a method based on alkaline gel electrophoresis for estimation of oxidative damage to DNA in Escherichia coli
Authors: Zirkle R. E. , Krieg N. R.
Published: March 2008

A method for estimating DNA strand breakage and subsequent repair based on alkaline gel electrophoresis was developed and tested with isogenic strains of Escherichia coli deficient in DNA repair enzymes. Samples from a cell suspension were removed at 2 min intervals following a 15 min exposure to 20 mmol l‐1 H2O2. Catalase was added and the cells were embedded in blocks of low‐melting point agarose and lysed. After alkaline gel electrophoresis, photographs of the gels were taken and the relative lengths of the distributions of DNA fragments were measured with a scanner and computer. The lengths were correlated with survival of the cells exposed to H2O2 and with the importance of particular DNA repair enzymes. Alkaline gel electrophoresis appears to be a relatively simple method for analysing the level of H2O2‐caused DNA damage and repair in E. coli.
Screening and selection of surfactant‐producing bacteria from waste lubricating oil
Authors: Mercadé M.E. , Monleón L. , de Andrés C. , Rodón I. , Martinez E. , Espuny M.J. , Manresa A.
Published: March 2008

Forty‐four strains with the ability to grow on waste lubricating oil as sole carbon source were isolated from soil‐contaminated samples and identified. Of these, four Rhodococcus and one Bacillus strain were selected for their capacity to lower the surface tension of culture medium from 55 mN m‐1 to less than or equal to 40 mN m‐1 and the interfacial tension between the culture medium and kerosene from 21 mN m‐1 to less than 5 mN m‐1, respectively. The surface‐active compounds, identified by means of TLC and specific reagents, from cultures of Rhodococcus strains and Bacillus were glycolipids and lipopeptide, respectively. The percentage loss of waste lubricating oil after 120 h of incubation ranged from 7.87% to 45.8% depending on the strain selected compared with uninoculated control. Decreases in paraffinic compounds and accumulation of new products, mainly with amide groups, were observed by direct and differential infrared spectrometry when selected strains grew on waste lubricating oil.
Survival of Staphylococcus aureus and enterotoxin A in glassy and rubbery states of gelatin
Authors: Bolton K.J. , Dodd C.E.R. , Gould G.W. , Waites W.M.
Published: March 2008

About 1% of Staphylococcus aureus cells survived the production of gelatin sheets containing nutrient broth. Those cells which survived showed no evidence of injury. Growth occurred in rubbery state gelatin with aw values of 0.98 and 0.93; viability decreased during storage at aw values of 0.89, 0.62 and 0.36 but there was little loss of viability in gelatin at an aw of 0.25 over 27 d storage at 26°C. Assays for enterotoxin A detected no synthesis of new toxin but no loss in pre‐formed toxin. The results suggest that high levels of Staph. aureus and its toxins should be excluded from glassy and rubbery state food products in order to prevent illness.
Effectiveness of massage, sucrose solution, herbal tea or hydrolysed formula in the treatment of infantile colic
Authors: Duygu Arikan , Handan Alp , Gözüm Sebahat , Orbak Zerrin , Karaca Çifçi Esra
Published: March 2008

Aim and objective.  The aim of the study was to evaluate the effectiveness of massage, sucrose solution, herbal tea or hydrolysed formula, each used individually in the treatment of infantile colic.

Background.  The term colic describes a group of symptoms that occur frequently in infants, consisting of paroxysmal abdominal pain and severe crying. Infant colic is of importance for both parents and the community health services that provide families with care, and is therefore an important clinical problem that is amenable to nursing interventions.

Design.  This prospective and randomised‐controlled study involved 175 infants in Turkey.

Methods.  Data were gathered by using Wessel criteria; parents wrote a daily structured diary, recording the onset and duration of crying. Patients were assigned randomly into four different intervention groups (massage, sucrose solution, herbal tea and hydrolysed formula) and control group. Duration of crying following each intervention was recorded in the diary by parents for a one week period.

Results.  There was a significant reduction in crying hours per day in all intervention groups. The difference between mean duration of total crying (hours/day) before and after the intervention infants in hydrolysed formula group was found higher than massage, sucrose and herbal tea group. The difference between mean duration of total crying(hours/day) before and after the intervention infants in massage group was found lower than other intervention groups and all groups.

Conclusion.  Our findings demonstrated that varied interventions such as administration of massage, sucrose solution, herbal tea and hydrolysed formula are effective in the treatment of colic. The difference between mean duration of total crying (hours/day) before and after the intervention in hydrolysed formula group was found higher than other intervention groups. Hydrolysed formula was the most effective in reducing the duration of crying (hours/day) when compared with the other intervention groups. Massage intervention yielded the least symptomatic improvement among all the interventions.

Relevance to clinical practice.  Colic treatment models used in this study can be used by nurses in neonatal and primary healthcare settings as an aid to families for the treatment of infantile colic.
Ozone inhalation induces exacerbation of eosinophilic airway inflammation and hyperresponsiveness in allergen‐sensitized mice
Authors: Kierstein S. , Krytska K. , Sharma S. , Amrani Y. , Salmon M. , Panettieri R. A. , Zangrilli J. , Haczku A.
Published: March 2008

Background:  Ozone (O3) exposure evokes asthma exacerbations by mechanisms that are poorly understood. We used a murine model to characterize the effects of O3 on allergic airway inflammation and hyperresponsiveness and to identify factors that might contribute to the O3‐induced exacerbation of asthma.

Methods:  BALB/c mice were sensitized and challenged with Aspergillus fumigatus (Af). A group of sensitized and challenged mice was exposed to 3.0 ppm of O3 for 2 h and studied 12 h later (96 h after Af challenge). Naive mice and mice exposed to O3 alone were used as controls. Bronchoalveolar lavage (BAL) cellular and cytokine content, lung function [enhanced pause (Penh)], isometric force generation by tracheal rings and gene and protein expression of Fas and FasL were assessed. Apoptosis of eosinophils was quantified by FACS.

Results:  In sensitized mice allergen challenge induced a significant increase of Penh and contractile force in tracheal rings that peaked 24 h after challenge and resolved by 96 h. O3 inhalation induced an exacerbation of airway hyperresponsiveness accompanied by recurrence of neutrophils and enhancement of eosinophils 96 h after allergen challenge. The combination of allergen and O3 exposure inhibited Fas and FasL gene and protein expression and eosinophil apoptosis and increased interleukin‐5 (IL‐5), granulocyte‐macrophage‐colony stimulating factor (GM‐CSF) and G‐CSF protein levels.

Conclusions:  O3 affects airway responsiveness of allergen‐primed airways indirectly by increasing viability of eosinophils and eosinophil‐mediated pathological changes.
Exercise‐induced asthma, respiratory and allergic disorders in elite athletes: epidemiology, mechanisms and diagnosis: Part I of the report from the Joint Task Force of the European Respiratory Society (ERS) and the European Academy of Allergy and Clinical Immunology (EAACI) in cooperation with GA2LEN
Authors: Carlsen K. H. , Anderson S. D. , Bjermer L. , Bonini S. , Brusasco V. , Canonica W. , Cummiskey J. , Delgado L. , Del Giacco S. R. , Drobnic F. , Haahtela T. , Larsson K. , Palange P. , Popov T. , Van Cauwenberge P.
Published: March 2008

Aims:  To analyze the changes in the prevalence of asthma, bronchial hyperresponsiveness (BHR) and allergies in elite athletes over the past years, to review the specific pathogenetic features of these conditions and to make recommendations for their diagnosis.

Methods:  The Task Force reviewed present literature by searching Medline up to November 2006 for relevant papers by the search words: asthma, bronchial responsiveness, EIB, athletes and sports. Sign criteria were used to assess level of evidence and grades of recommendation.

Results:  The problems of sports‐related asthma and allergy are outlined. Epidemiological evidence for an increased prevalence of asthma and BHR among competitive athletes, especially in endurance sports, is provided. The mechanisms for development of asthma and bronchial hyperresponsiveness in athletes are outlined. Criteria are given for the diagnosis of asthma and exercise induced asthma in the athlete.

Conclusions:  The prevalence of asthma and bronchial hyperresponsiveness is markedly increased in athletes, especially within endurance sports. Environmental factors often contribute. Recommendations for the diagnosis of asthma in athletes are outlined.
The clinical and pharmacoeconomic analysis of invasive aspergillosis in adult patients with haematological diseases
Authors: Cagatay A. Atahan , Cosan F. , Karadeniz A. , Besısık S. K. , Ozsut H. , Nalcaci M. , Pekcelen Y. , Eraksoy H. , Dincol G. , Calangu S.
Published: March 2008

Invasive pulmonary aspergillosis (IPA) poses major management problems for clinicians caring for patients with haematological diseases. The clinical courses of patients with IPA who had been hospitalised in Hematology Unit, Bone Marrow Transplantation Unit and Infectious Diseases and Clinical Microbiology Unit between 1998 and 2005, the efficacy and adverse effects and costs of antifungal drugs (conventional amphotericin B deoxycholate, liposomal amphotericin B, amphotericin B lipid complex and caspofungin) used in the therapy of these patients were analysed in this study. Ninety‐three patients with IPA were reviewed retrospectively. Mean age of the patients was 40.4 ± 15.1 years (range 14–70 years). Fifty‐eight male patients and 35 female patients were included in the study. Manageable hypopotassemia, nausea/vomiting and headache were the most commonly observed side‐effects during antifungal (AF) therapy. While it was not found to be statistically significant with regard to the mean time to resolution of fever (P = 0.8), it was found to be statistically significant with regard to radiological regression at 30th day, and mean duration of therapy between patients who were dead or alive (P < 0.05, P < 0.001). Total cost of AF therapy for 93 patients was found to be US$4 461 824 (minimum US$387‐maximum US$279 023). Of this amount, US$4 272 845 represents the payment for AF drugs, US$188 979 the payment for other expenditures. Mean cost of therapy for a patient with IPA was found to be US$49 336. Although it seemed to be difficult, investigations should primarily focus on providing standardisation of parameters relating to the duration of AF therapy. Despite the less‐than‐optimal safety profile of CAB, it often remains to be the preferred first line option for the treatment of fungal infections because of its broad spectrum, activity and low acquisition cost.