bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimicrobial activity of the major components of the essential oil of Melaleuca alternifolia
Authors: Carson C.F. , Riley T.V.
Published: March 2008

Tea tree oil, or the essential oil of Melaleuca alternifolia, is becoming increasingly popular as a naturally occurring antimicrobial agent. The antimicrobial activity of eight components of tea tree oil was evaluated using disc diffusion and broth microdilution methods. Attempts were also made to overcome methodological problems encountered with testing compounds which have limited solubility in aqueous media. After assessing media with and without solubilizing agents, the disc diffusion method was used to determine the susceptibility of a range of micro‐organisms to 1,8‐cineole, 1‐terpinen‐4‐ol, ρ‐cymene, linalool, α‐terpinene, γ‐terpinene, α‐terpineol and terpinolene. While the disc diffusion method lacked reproducibility, it was considered useful as a procedure for screening for antimicrobial activity. Terpinen‐4‐ol was active against all the test organisms while ρ‐cymene demonstrated no antimicrobial activity. Linalool and α‐terpineol were active against all organisms with the exception of Pseudomonas aeruginosa. Minimum inhibitory and minimum cidal concentrations of each component against Candida albicans, Escherichia coli and Staphylococcus aureus were determined using a broth microdilution method. Modifications to this method overcame solubility and turbidity problems associated with the oil components and allowed the antimicrobial activity of each of the components to be quantified reproducibly. There was reasonable agreement between minimum inhibitory concentrations and zones of inhibition. These results may have significant implications for the future development of tea tree oil as an antimicrobial agent.
Selective action of inhibitors used in different culture media on the competitive microflora of Salmonella
Authors: Arroyo G. , Arroyo J.A.
Published: March 2008

The action of 12 inhibitors employed in the culture media used to detect the presence of Salmonella in food on 24 bacterial strains including contaminating Gram‐positive bacteria common in water and food, Gram‐negative bacteria, especially Enterobacteriaceae and Pseudomonadaceae, which are components of the competitive microflora, and six Salmonella serotypes was tested. Two liquid culture media (AR 5 and AE 1) were used. Series of tubes containing increasing concentrations of each inhibitor were inoculated with the test strains and incubated at 37°C until growth was verified spectrophotometrically (24–48 h). The results showed that the inhibitors were effective against the Gram‐positive contaminating microflora. They did not preferentially inhibit the competitive microflora of Salmonella, chiefly Enterobacteriaceae, and were ineffective against the Pseudomonas strains, which can tolerate concentrations higher than those customarily employed in culture media.
Influence of ethanol and temperature on the cellular fatty acid composition of Zygosaccharomyces bailii spoilage yeasts
Authors: Couto M. Margarida Baleiras , Veld J.H.J. Huis in't
Published: March 2008

Changes in the fatty acid profile of Zygosaccharomyces bailii strains, isolated from different sources, after growth at increasing concentrations of ethanol and/or decreasing temperatures were determined. Differences in fatty acid composition between Zygosaccharomyces bailii strains at standard conditions (25°C, 0% initial ethanol) were observed and could be related to ethanol tolerance. Zygosaccharomyces bailii strain isolated from wine showed the highest ethanol tolerance in relation to growth rate. Surprisingly, an increase in ethanol concentration or a decrease in growth temperature caused a decrease in the degree of unsaturation of total cellular fatty acids. On the other hand, the mean chain length increased (high ethanol concentration) or decreased (low temperature) depending on the stress factor. When both stress situations (high ethanol concentration and low temperature) were present at the same time, the degree of unsaturation remained approximately constant. With decreasing temperatures, the C16/C18 ratio increased in studies of initial ethanol content below 5%, and above 5% ethanol, decreased.
Survival of free and alginate‐encapsulated Pseudomonas aeruginosa UG2Lr in soil treated with disinfectants
Authors: Weir S. C. , Lee H. , Trevors J. T.
Published: March 2008

Pseudomonas aeruginosa UG2Lr, a rifampicin‐resistant strain possessing the luxAB on a chromosomal Tn5 insert, was inoculated into soil microcosms as either free cells or encapsulated in dry alginate beads. A 100‐fold increase in cell number g‐1 dry soil was observed in microcosms inoculated with alginate‐encapsulated UG2Lr after 3 weeks incubation at 22°C compared to microcosms inoculated with free cells. After 98 d, microcosms inoculated with free UG2Lr cells contained 104 cfu g‐1 dry soil compared to 107 cfu g‐1 dry soil in microcosms inoculated with alginate‐encapsulated UG2Lr cells. The effects of disinfectants on both the free and alginate‐encapsulated UG2Lr cells were also examined. 1·0% (w/g dry soil) calcium hypochlorite, formaldehyde and Spectrum Clear Bath, were added to microcosms each week for 4 weeks. Formaldehyde killed both free and alginate‐encapsulated UG2Lr cells within 14 d after only two amendments. Calcium hypochlorite reduced free UG2Lr cell numbers 10‐fold 2 d after initial application; however, the introduced population recovered and was unaffected by subsequent treatments at 7, 14 and 21 d. Alginate‐encapsulated UG2Lr cells were not affected by calcium hypochlorite treatment. Spectrum Clear Bath did not kill either free or alginate‐encapsulated UG2Lr cells in soil. Alginate encapsulation improved survival of introduced bacteria in soil except in the presence of formaldehyde. Killing genetically‐engineered bacteria in soil may be difficult unless a powerful disinfectant such as formaldehyde is used or the genetically‐engineered micro‐organism is allowed to become non‐viable over time.
Bacillus thuringiensis populations naturally occurring on mulberry leaves: a possible source of the populations associated with silkworm‐rearing insectaries
Authors: Ohba M.
Published: March 2008

Mulberry leaves were examined for the occurrence of Bacillus thuringiensis. This organism was recovered from both abaxial and adaxial surfaces: a total of 186 B. thuringiensis colonies were isolated from 24 (96·0%) out of 25 mulberry trees, and from 112 (11·2%) out of 1004 leaves from 25 trees. The frequency of B. thuringiensis colonies was 3·2% among 5900 colonies belonging to the Bacillus cereus/B. thuringiensis group. Single colonies were associated with 75·9% of the B. thuringiensis‐positive leaves and 2–16 colonies were occasionally found on a single phylloplane. Flagellar (H) serotypying of the isolates revealed that, among the 19 H serotypes (serovars) detected, the H serotype 13 (serovar pakistani) was the predominant, followed by the H serotypes 3abc (kurstaki), 6ac (oyamensis), 16 (indiana), 24 (neoleonesis), 4ac (kenyae), 7 (aizawai) and 10 (darmstadiensis). Larvicidal activity, against the silkworm (Bombyx mori) and/or the mosquito (Aedes aegypti), was exhibited by 18 isolates (9·7%) belonging to H serovars kurstaki, kenyae, canadensis and aizawai, and an unidentified H serogroup.
Recovery of bacterial spores dried on aluminium strips
Authors: Sugimoto E.E. , Raasch A.J. , Ehioba R.M.
Published: March 2008

Bacterial spores dried on aluminium strips are used in microbiological validation of packaging and processing systems. Vortex agitation and sonication in Butterfield's buffer, 70% ethanol or 0·1% Tween 80 were evaluated for ease of recovery of bacillus spores dried on aluminium strips to compare the concentration of dried spores to dilutions used to inoculate such strips. The highest recovery for Bacillus subtilis var. globigii spores was observed with sonication in 70% ethanol with average recovery close to the initial inoculum. The highest recovery for B. stearothermophilus spores was with sonication in Butterfield's buffer, averaging 0·8 log less recovery than the initial inoculum. Bacillus subtilis var. globigii spores were recovered from strips in greater numbers than B. stearothermophilus spores for all treatment medium combinations. Scanning electron microscopy revealed unrecovered spores adhering to strips after treatment. Recovery of B. subtilis var. globigii spores decreased with time over the 4 week storage period.
An oligonucleotide hybridization assay for the identification and enumeration of F‐specific RNA phages in surface water
Authors: Beekwilder J. , Nieuwenhuizen R. , Havelaar A.H. , van Duin Leiden J.
Published: March 2008

F‐specific RNA phages can be used as model organisms for enteric viruses to monitor the effectiveness of sewage treatment, and to assess the potential contamination of surface water with these viruses. In this paper a method is described which identifies RNA phages quantitatively by a plaque hybridization assay. Oligonucleotide probes were developed that can assign phages to their phylogenetic subgroups. Such a distinction is important, since some subgroups preferentially occur in sewage of human origin, while others tend to be associated with animal wastewater. The method has been tested on a large number of isolates and represents an improvement in time and reliability over the previously used serological classification.
Biological indicators for low temperature steam and formaldehyde sterilization: investigation of the effect of change in temperature and formaldehyde concentration on spores of Bacillus stearothermophilus NCIMB 8224
Authors: Wright A.M. , Hoxey E.V. , Soper C.J. , Davies D.J.G.
Published: March 2008

A.M. WRIGHT, E.V. HOXEY, C.J. SOPER AND D.J.G. DAVIES. 1996. Five strains of Bacillus stearothermophilus have been studied to identify a spore strain to be used as a biological indicator organism for low temperature steam and formaldehyde sterilization. Three strains gave poor reproducibility of batch size and growth index and were discarded. The other two strains gave good reproducibility with a high growth index and gave rise to linear survivor curves when exposed to 5% aqueous formaldehyde. However, only NCIMB 8224 sporulates on a simpler medium and as it was the most resistant to formaldehyde, it was further studied. Tests were carried out in a modified miniclave and factors studied included temperature of the steam and formaldehyde concentration. All studies confirmed the suitability of this strain as a biological indicator organism.
Effect of two levels of transgalactosylated oligosaccharide intake in rats associated with human faecal microflora on bacterial glycolytic activity, end‐products of fermentation and bacterial steroid transformation
Authors: Kikuchi H. , Andrieux C. , Riottot M. , Bensaada M. , Popot F. , Beaumatin P. , Szylit O.
Published: March 2008

The effects of two levels of transgalactosylated oligosaccharide (TOS) intake on bacterial glycolytic activity, end products of fermentation and bacterial steroid transformation were studied in rats associated with a human faecal flora. Rats were fed a human‐type diet containing 0, 5 or 10% TOS. Caecal pH decrease correlated with the amount of TOS in the diet. Intake of the TOS diet induced a decrease in blood cholesterol and a strong increase in β‐galactosidase activity in the hindgut. TOS fermentation led to production of hydrogen and short chain fatty acids, whereas ammonia and branched‐chain fatty acids were decreased. A diet containing 10% TOS increased caecal lactic acid concentrations and reduced β‐glucuronidase activities and steroid transformation.
Production of bacteriolytic enzymes as a tool for characterizing enterococci
Authors: Berlutti F. , Thaller M.C. , Rossolini G.M. , Pantanella F. , Schippa S. , Pezzi R.
Published: March 2008

Bacteriolytic enzymes secreted by log‐phase cultures of enterococci (Enterococcus faecalis, Ent. faecium, Ent. durans, Ent. hirae, Ent. casseliflavus, Ent. avium, Ent. mundtii) were analysed by means of a zymogram technique to resolve activities according to the size of their polypeptide component and their specificities towards different substrates. Heterogeneous patterns of lytic activity were observed with different species. For each test substrate, homogeneous patterns of lytic activities were observed with strains of the same species, except for Ent. faecalis strains, which showed heterogeneous lytic patterns even towards the same substrate, and could be divided into at least four different groups according to their lytic pattern. No lytic activity was common to all strains tested. Results of zymogram analysis of Enterococcus bacteriolytic enzymes were consistent with current knowledge on enterococcal taxonomy, indicating that this analytical approach may be a useful tool for fine‐tuned characterization of different enterococcal strains.
Control of microbiological quality and shelf‐life of catfish (Clarias gariepinus) by chemical preservatives and smoking
Authors: Efiuvwevwere B.J.O. , Ajiboye M. O.
Published: March 2008

Fresh catfish (Clarias gariepinus) were subjected to different concentrations of sodium benzoate or potassium sorbate and smoked traditionally before evaluation for microbiological, chemical and organoleptic characteristics during ambient tropical storage. Unsmoked fish samples showed diverse microflora (Enterobacter, Escherichia, Serratia, Bacillus, Staphylococcus, Streptococcus, Penicillium, Aspergillus and Achlya genera) while smoked samples were dominated by Gram‐positive bacterial flora (Bacillus, Staphylococcus and Streptococcus) and spoilage moulds (Penicillium verrucosum, Aspergillus flavus and Achlya spp.). Significant reduction in microbial population occurred in most samples following smoking with samples subjected to 0.4% (w/v) potassium sorbate showing the lowest microbial load and maximum shelf‐stability. However, marked microbial increase occurred after day 4 of storage in control and benzoate‐treated samples. Changes in pH were marginal but decreased after day 12 of storage. Moisture content decreased sharply after smoking and remained low after day 4 of storage. Overall, potassium sorbate treatment (0.4% w/v) was most effective in controlling microbial quality and extended the shelf‐life of the samples by 8 d.
Characterization of Rhizobium ‘hedysari’ by RFLP analysis of PCR amplified rDNA and by genomic PCR fingerprinting
Authors: Selenska‐Pobell S. , Evguenieva‐Hackenberg E. , Radeva G. , Squartini A.
Published: March 2008

The taxonomic and discriminatory power of RFLP analysis of PCR amplified parts of rhizobial rrn operons was compared to those of genomic PCR fingerprinting with arbitrary and repetitive primers. For this purpose, the two methods were applied for characterization of a group of bacterial isolates referred to as Rhizobium ‘hedysari’. As outgroups, representatives of the family Rhizobiaceae, belonging to the Rhizobium galegae, Rhizobium meliloti, Rhizobium leguminosarum and Agrobacterium tumefaciens species were used. By the RFLP analysis of the PCR products corresponding to the variable 5′‐half of the 23S rRNA gene and of the amplified spacer region between the 16S and 23S rRNA genes all Rh. ‘hedysari’ strains studied were tightly clustered together while the outgroups were placed in an outer position. The PCR products of the 3’ end parts of the 23S rDNA did not show significant RFL polymorphism and no species differentiation on their basis was possible. In parallel, analysis of the same strains was performed by PCR amplification of their total DNA with 19, 18 and 10 bp long arbitrary primers (AP‐PCR) as well as with single primers corresponding to several bacterial repetitive sequences (rep‐PCR). By both AP and rep‐PCR an identification of every particular strain was achieved. In general, all primers provided taxonomic results that are in agreement with the species and group assignments based on the RFLP analysis of the rrn operons. On the basis of the results presented here it can be concluded that AP and rcp‐PCR are more informative and discriminative than rDNA and RFLP analysis of the rhizobial strains studied.
Differentiation between Mycobacterium tuberculosis and Mycobacterium bovis by a multiplex‐polymerase chain reaction
Authors: Herrera E.A. , Pérez O. , Segovia M.
Published: March 2008

A multiplex‐polymerase chain reaction (PCR) assay, based on one‐step amplification and detection of three different mycobacterial genomic fragments, was designed for differentiation between Mycobacterium bovis and Mycobacterium tuberculosis. The oligonucleotide primers were chosen from the gro EL gene, present in the genus Mycobacterium sp., from the IS 6110 insertion sequence, present in Myco. tuberculosis complex and from the mtp 40 gene, identified as a specificspecies Myco. tuberculosis genomic fragment. This amplification method allowed the detection of two fragments of 576 and 317 base pairs in Myco. bovis and three fragments of 576, 396 and 317 base pairs in Myco. tuberculosis strains, including atypical strains of Myco. tuberculosis where the copy number of the IS 6110 element is low. The multiplex‐PCR assay described may be a very useful tool for the rapid and specific differentiation of these related mycobacteria and easy to use in medical and veterinary microbiology laboratories.
Note: Development of an external quality assurance scheme for the detection and enumeration of Pseudomonas aeruginosa from water and comparison of results using modified King's A broth and a commercial agar
Authors: Place B.M. , Tillett H.E. , Lightfoot N.F.
Published: March 2008

Two trials of the isolation and enumeration of a given strain of Pseudomonas aeruginosa from water are reported. In each trial participants received concentrated samples from two batches, one with low and one with high counts, to be diluted to 500 ml in sterile distilled or deionized water and examined for Ps. aeruginosa by membrane filtration. Membranes were incubated at 37°C for 48 h on pads soaked in modified King's A broth (MKAB) and Unipath Pseudomonas Agar plus CFC supplement (PCFC). The first trial involved eight Public Health Laboratories (PHL) and the organizers provided media from single batches. The second trial, involving 50 PHL, examined the feasibility of a large scale external quality assessment (EQA) distribution. Participants were invited to use the same two media and their usual medium if different. Average counts were close to expected and the spread of results was comparable to that observed from the EQA scheme for indicator organisms. From the results of the two trials a better isolation of the strain of Ps. aeruginosa under consideration was noted with PCFC compared with MKAB.
Immunomagnetic isolation of Xanthomonas campestris pv. pelargonii
Authors: Jones J.B. , van Vuurde J.W.L.
Published: March 2008

Immunomagnetic fishing was developed as an improved procedure for increasing the bacterial target to non‐target recovery ratio in suspensions containing mixtures of target and non‐target organisms. A cell suspension containing the target Xanthomonas campestris pv. pelargonii and non‐target organisms, is treated with rabbit polyclonal antiserum against X.c. pv. pelargonii and incubated for 1 h. The suspension is then mixed with paramagnetic iron oxide particles coated with goat anti‐rabbit antibodies (immunomagnetic particles). After incubation, the polished surface of a 14 mm diameter neodymium supermagnet is placed at the air‐water interace and the magnetic particles are attracted to the magnet. After all visible magnetic particles have attached to the bottom of the magnet, the magnet is dipped in sterile buffer to remove non‐target organisms. The magnet with attached magnetic particles is rubbed evenly over an agar surface to dislodge the particles and attached bacteria. Conventional immunomagnetic isolation (immunomagnetic attraction) and immunomagnetic fishing were compared, for the recovery of the target organism in geranium leaf washings spiked with X.c. pv. pelargonii. With immunomagnetic attraction and immunomagnetic fishing, bacterial non‐target organisms were reduced to 11.4 and 1.5% of the initial population, respectively, whereas the target was only reduced to 63.7 and 53.8%.
Inducible transport of citrate in Lactobacillus rhamnosus ATCC 7469
Authors: Figueroa R.M. de , Benito de Cárdenas I.L. , Sesma F. , Alvarez F. , de Ruiz Holgado A. P. , Oliver G.
Published: March 2008

Lactobacillus rhamnosus ATCC 7469 exhibited diauxie when grown in a medium containing both glucose and citrate as energy source. Glucose was used as the primary energy source during the glucose‐citrate diauxie. Uptake of citrate was carried out by an inducible citrate transport system. The induction of citrate uptake system was repressed in the presence of glucose. This repression was reversible and mediated by cAMP.
The development of a conductimetric assay for automated detection of metabolically active soft rot Erwinia spp. in potato tuber peel extracts
Authors: Fraaije B. A. , Birnbaum Y. , Franken A. A. J. M. , Van den Bulk R.W.
Published: March 2008

Four media were tested for their ability to detect the soft rot potato pathogens Erwinia chrysanthemi (Ech) and Erwinia carotovora ssp. atroseptica (Eca) in potato tubers by means of automated conductance measurements. The specificity of the conductimetric assays was determined by testing a set of different Erwinia spp. and potato‐associated saprophytes, including the genera Pseudomonas, Bacillus, Enterobacter and Flavobacterium. All bacteria tested produced conductance responses in Special Peptone Yeast Extract, whereas in minimal medium with L‐asparagine only Erwinia spp. and Pseudomonas spp. were able to generate large conductance responses. In minimal medium supplemented with glucose and trimethylamine‐N‐oxide only Enterobacteriaceae, Erwinia spp. included, generated conductance responses, while with pectate as sole carbon source only Erwinia spp. produced distinct conductance responses. The pectate medium proved to be particularly useful for specific automated conductimetric detection of Erwinia spp. in potato peel extracts. Within 48 h, the detection threshold of the conductimetric assay for Eca varied between 102 and 103 cfu per ml peel extract at both incubation temperatures of 20° and 26°C. Ech was detected at concentrations of 104–105 or 103–104 cfu ml‐1 at 20° and 26°C, respectively. To eliminate ‘false’‐positive reactions in conductimetry caused by Erwinia carotovora ssp. carotovora, results of the conductance measurements have to be confirmed by other techniques, like serology or DNA assays.
Characterization of temperate bacteriophages of Leuconostoc oenos and evidence for two prophage attachment sites in the genome of starter strain PSU‐1
Authors: Santos R. , Vieira G. , Santos M.A. , Paveia H.
Published: March 2008

The close relatedness between 17 Leuconostoc oenos bacteriophages, induced with mitomycin C from strains isolated in different geographic regions, was inferred from their morphology, DNA homology and protein composition. The genome of all the phages had cohesive end termini and ranged in size from 36.4 to 40.9 kb. According to the restriction patterns obtained by digestion with five enzymes, the phages were divided in six groups. Lysogenization of a spontaneous phage‐cured derivative of Leuc. oenos strain PSU‐1 was achieved with 16 phages and the analysis of the lysogens showed that the phage DNA integrates in the host chromosome in one or two sites. The att B loci were located on the macrorestriction Asc I and Not I fragments of the recipient strain. A survey of Leuc. oenos strains with a phage DNA probe confirmed the lysogenic nature of several, but not all of the original phage hosts. These results are discussed in the light of evidence for the instability of some lysogenic PSU‐1 derivatives.
Developments in microbiological risk assessment models for drinking water—a short review
Authors: Gale P.
Published: March 2008

Microbiological risk assessment (MRA) is the emerging method to predict the risks of infection from waterborne pathogens (e.g. rotavirus and Cryptosporidium parvum) in the drinking water supply. The objectives of this paper are to review the appropriateness of current models, with emphasis on pathogen exposures through drinking water, and to consider the information necessary to further their development. Calculating pathogen exposures in MRA is currently limited by the fact that pathogen density data for drinking water supplies are only available for very large volume samples—much larger than imbibed daily by any consumer. To develop MRA, information is needed on how pathogens are dispersed within those large volumes at the resolution of volumes typically consumed daily by individuals. Available evidence suggests that micro‐organisms, including pathogens, are clustered to some degree, even within small volumes, exposing some drinking water consumers to much higher doses than others. By assuming pathogens are randomly dispersed, current models overestimate the risk from the more infectious agents (e.g. rotaviruses) but underestimate the risk from less infectious pathogens (e.g. C. parvum). Approaches to modelling pathogen densities in drinking water from source water data and treatment removal efficiencies require additional information on the degree to which treatment processes (e.g. filtration and coagulation) increase pathogen clustering. The missing information could be obtained from large‐scale pilot plant studies.
Colonization by lactobacilli of piglet small intestinal mucus
Authors: Rojas M. , Conway P.L.
Published: March 2008

The colonization potential of lactobacilli was investigated using small intestinal mucus extracts from 35‐d‐old pigs. Mucus‐secreting tissue from the small intestine of piglets was gently rinsed to remove contents and then shaken in buffer to release mucus from the surface. Numbers of lactobacilli in different portions of the small intestine of 35‐d‐old pigs were enumerated. Also, mucus isolated from the small intestine of pigs was investigated for its capacity to support the growth of lactobacilli. Results indicated that Lactobacillus spp. inhabit the mucus layer of the small intestine and can grow and adhere to ileal mucus. From adhesion studies of Lactobacillus fermentum 104R to mucus analysed by Scatchard plot, it is suggested that an associating system showing positive cooperativity is involved. Proteinaceous compound(s) involved in the adhesion to mucus were detected in the spent culture fluid from the growth of strain 104R. Studies are continuing in order to identify and characterize the adhesion‐promoting protein(s). From the data, it is proposed that lactobacilli colonize the mucus layer of the small intestine of pigs.
An assessment of three selective media for bifidobacteria in faeces
Authors: Silvi S. , Rumney C.J. , Rowland I.R.
Published: March 2008

Three previously described media enumerating Bifidobacterium spp. in faeces were compared with respect to their selectivity and quantitative recovery. The results of this study indicate that of the three media studied, Beerens’agar is the most suitable medium for isolation and enumeration of Bifidobacterium spp. from the gut microflora.
First finding of urease‐positive thermophilic strains of Campylobacter in river water in the Far East, namely, in Japan and their phenotypic and genotypic characterization
Authors: Matsuda M. , Kaneko A. , Fukuyama M. , Itoh T. , Shingaki M. , Inoue M. , Moore J.E. , Murphy P.G. , Ishida Y.
Published: March 2008

Two strains of urease‐positive thermophilic Campylobacter (UPTC), CF89–12 and CF89–14, which were identified as UPTC by biochemical characterization, were found for the first time in river water in the Far East, namely, in Japan. The biochemical characteristics were identical to those of strains described previously by Bolton and colleagues. Furthermore, these two strains were positive for arylsulphatase. Consequently, it was demonstrated that UPTC may possibly be differentiated phenotypically from Campylobacter lari by the arylsulphatase test, as well as urease and nalidixic acid tests. Analysis by pulsed‐field gel electrophoresis (PFGE) after digestion with Apa I, Sal I and Sma I, which were found to produce distributions of DNA fragments to be suitable for analysis of the genomic DNA from the thermophilic Campylobacter, respectively, demonstrated that these three restriction enzymes produced distributions of a relatively limited number of genomic DNA fragments and also demonstrated that the PFGE profiles obtained with the three restriction enzymes were indistinguishable between the two strains, respectively. The PFGE analysis and conventional fixed‐field agarose gel electrophoresis suggested that the both genomes were approximately 1862 kb in length. Even though the two isolates of UPTC were isolated from water in different rivers in Japan, the results suggested that a single strain. as opposed to two distinct strains, was isolated. PFGE profiles after digestion with Sal I and Sma I, respectively, were also demonstrated to be distinctly different among strains isolated in Japan and previously in Europe. This is the first example of the isolation of UPTC from natural sources in countries other than those in Europe.
Isolation, partial characterization and mode of action of acidocin J1229, a bacteriocin produced by Lactobacillus acidophilus JCM 1229
Authors: Tahara T. , Kanatani K.
Published: March 2008

Lactobacillus acidophilus JCM 1229 produces a heat‐stable bacteriocin, designated as acidocin J1229, that has a narrow inhibitory spectrum. Production of acidocin J1229 in MRS broth was pH dependent, with maximum activity detected in broth culture maintained at pH 5:0. Acidocin J1229 was purified by ammonium sulphate precipitation and sequential cation exchange and reversed‐phase chromatographies. The sequence of the first 24 amino acid residues of the N terminus of acidocin J1229 was determined. The molecular mass of acidocin J1229 as determined by mass spectrometry was 6301 Da. Acidocin J1229 showed a bactericidal effect but not a bacteriolytic effect on sensitive cells. Acidocin J1229 dissipated the membrane potential and the pH gradient in sensitive cells, which affected such proton motive force‐dependent processes as amino acid transport. Acidocin J1229 also caused an efflux of glutamate, previously taken up via a unidirectional ATP‐driven transport system. Secondary structure prediction revealed the presence of an amphiphilic a‐helix region that could form hydrophilic pores. These results suggest that acidocin J1229 is a pore‐forming peptide that creates cell membrane channels through the ‘barrel‐stave’mechanism.
Note: Isolation, characterization and epidemiology of Yersinia enterocolitica from humans and animals
Authors: Zheng X.B. , Xie C.
Published: March 2008

During an 11‐year period (1983 to 1994), 51 strains of Yersinia enterocolitica were isolated from humans and animals. Specimens were collected from a total of 3601 sources consisting of 956 patients with enteritis, 300 patients with urinary tract infection, 1564 healthy humans, 510 swine, 38 guinea‐pigs, 118 rats and 115 rabbits. Five strains of Y. enterocolitica, bio/serogroups 2/O:9 and 4/O:3, virulence positive, were recovered from patients. Forty‐two variants of Y. enterocolitica belonging to pathogenic serogroup O:3, Voges‐Proskauer‐negative biogroup 3 were recovered from swine, rats and rabbits. The rate of isolation of Y. enterocolitica from diarrhoeal swine was apparently greater than those from healthy swine. The incidence of human infections due to Y. enterocolitica was very low and bioserogroups of isolates were different from the strains which were isolated from animals. There was no evidence to suggest that swine were the source of Y. enterocolitica in humans.
The hygienic efficiency of conventional and inverted lamb dressing systems
Authors: Bell R.G. , Hathaway S.C.
Published: March 2008

R.G. BELL AND S.C. HATHAWAY. 1996. Aerobic plate counts (APC 37°C and APC 25°C) and Escherichia coli enumerations (Petrifilm) were used to determine sources of bacterial contamination during sheep dressing, determine the hygienic efficacy of hand wash and knife ‘sterilization’procedures and compare the hygiene efficiency of conventional and inverted sheep dressing systems. The major slaughterline sources of microbial contamination were: fleece > workers' hands > faecal pellets > knife blades. Aerobic plate counts (APC 37°C) exceeding log 4.4 cfu cm‐2 were considered indicative of direct fleece contact, whereas E. coli numbers exceeding log 3.3 cfu cm‐2 were considered indicative of direct faecal contact. A 44°C water hand rinse removed 90% of the microbial contamination from workers' hands, but rinsed hands, particularly those contacting the fleece, still carried a microbial population exceeding log 4.0 cfu cm‐2. A 44°C rinse followed by an 82°C water dip reduced the contamination on knife blades to less than log 3.0 cfu cm‐2. Inverted dressing systems produced carcasses with a lower contamination level than conventional systems. With both systems little increase in contamination occurred after pelt removal. The areas of highest contamination were the forequarter region with inverted dressing and the hindquarter with conventional dressing. In both cases these regions are the sites where cuts are made through the skin. With both systems contamination around these cuts was entirely consistent with direct fleece contact resulting from ‘rollback’.
A comparative evaluation with respect to the bacterial cleanability of a range of wall and floor surface materials used in the food industry
Authors: Taylor J.H. , Holah J.T.
Published: March 2008

J. H. TAYLOR AND J. T. HOLAH. 1996. A range of floor and wall materials suitable for use in the food industry were selected for comparative bacterial cleanability tests. A standard cleaning regime was carried out on samples after biofilm development of Acinetobacter calcoaceticus (CRA 296). Cleanability was measured as the log reduction in bacterial numbers. The results for the wall materials showed that there were no statistical differences, whilst those for the floor materials were more variable. The grouted joints and texture did not compromise the cleanabilities of tiled surfaces.
Brewery yeast as a biosorbent for uranium
Authors: Omar N. B. , Merroun M. L. , González‐Muñoz M. T. , Arias J. M.
Published: March 2008

N. B. OMAR, M. L. MERROUN, M. T. GONZÁLEZ‐MUÑOZ AND J. M. ARIAS. 1996. Yeast cells are capable of carrying out biosorption with various heavy metals. The biomass deriving from Saccharomyces cerevisiae coming from brewing industries is a by‐product that is possible to be used in the purification of water contaminated with these ions. In this paper we show that yeast biomass from one of the city's breweries can adsorb uranium efficiently, up to 2.4mmol of this metal per gram of dry biomass. It can also be seen that the temperature (between 10° and 37°C) has no effect on the biosorption, while pH does have an influence, 4.5 being the best value. When the concentrations of uranium range between 0.1 and 0.5 mol 1‐1 the yeast dry biomass is capable of adsorbing between 84% and 98% of this metal in solution.
Survival of cells and DNA of Aeromonas salmonicida released into aquatic microcosms
Authors: Deere D. , Porter J. , Pickup R.W. , Edwards C.
Published: March 2008

D. DEERE, J. PORTER, R.W. PICKUP AND C. EDWARDS. 1996. The survival of the bacterial fish pathogenAeromonas salmonicida, and persistence of its DNA, were monitored in aquatic microcosms using selective culture and most probable number PCR. Bacterial cells and naked DNA were released into natural non‐sterile microcosms consisting of lake sediment overlayered with lake water. Two different types of surface sediment were used. One was sandy in character, taken from the shoreline whilst the other was a littoral loamy surface mud. Inoculated cells and naked DNA became undetectable from water overlayers within 4 weeks of release. Colony counts ofAer. salmonicidadeclined below detectable limits after 4 weeks in loamy sediment or 7 weeks in sandy sediment; however, naked DNA and DNA from released cells remained detectable for more than 13 weeks.
The effect of chlorhexidine on defined, mixed culture oral biofilms grown in a novel model system
Authors: Kinniment S.L. , Wimpenny J.W.T. , Adams D. , Marsh P.D.
Published: March 2008

In order to develop an improved method to evaluate antimicrobial agents for use in clinical dentistry, a constant‐depth film fermenter (CDFF) has been used to generate biofilms of fixed depth comprising nine species of bacteria commonly found in dental plaque in health and disease. These bacteria were grown together initially in a conventional chemostat which was used to inoculate the CDFF over an 8 h period. Medium was then supplied directly to the CDFF and biofilms allowed to develop. The biofilms were then challenged with eight short pulses of two concentrations of chlorhexidine (0·0125 and 0·125% w/v). The lower concentration had a limited effect on the composition of the biofilms while a differential and substantial inhibition was obtained with a higher concentration. Actinomyces naeslundii was lost from the biofilm, and the viable counts of streptococci, Fusobacterium nucleatum and Porphyromonas gingivalis were inhibited by over three orders of magnitude by 0·125% chlorhexidine, whereas Veillonella dispar was only transiently affected. The findings were consistent with those from clinical studies of dental plaque, suggesting that this model would have a predictive value when evaluating novel antiplaque or antimicrobial inhibitors.
Genetic impoverishment of the last black grouse (Tetrao tetrix) population in the Netherlands: detectable only with a reference from the past
Authors: LARSSON J. KARL , JANSMAN HUGH A. H. , SEGELBACHER GERNOT , HÖGLUND JACOB , KOELEWIJN HANS PETER
Published: March 2008

We have studied a small isolated population of black grouse (Tetrao tetrix) in the Netherlands to examine the impact of isolation and reduction in numbers on genetic diversity. We compared the genetic diversity in the last extant Dutch population with Dutch museum samples and three other black grouse populations (from England, Austria and Norway, respectively) representing isolated and continuous populations. We found significantly lower allelic richness, observed and expected heterozygosities in the present Dutch population compared to the continuous populations (Austria and Norway) and also to the historical Dutch population. However, using a bottleneck test on each population, signs of heterozygosity excess were only found in the likewise isolated English population despite that strong genetic drift was evident in the present Dutch population in comparison to the reference populations, as assessed both in pairwise FST and structure analyses. Simulating the effect of a population reduction on the Dutch population from 1948 onwards, using census data and with the Dutch museum samples as a model for the genetic diversity in the initial population, revealed that the loss in number of alleles and observed heterozygosity was according to genetic drift expectations and within the standard error range of the present Dutch population. Thus, the effect of the strong decline in the number of grouse on genetic diversity was only detectable when using a reference from the past. The lack of evidence for a population reduction in the present Dutch population by using the program bottleneck was attributed to a rapidly found new equilibrium as a consequence of a very small effective population size.
Haplotype reconstruction for scnp DNA: a consensus vote approach with extensive sequence data from populations of the migratory locust (Locusta migratoria)
Authors: HUANG ZU‐SHI , JI YA‐JIE , ZHANG DE‐XING
Published: March 2008

Single copy nuclear polymorphic (scnp) DNA is potentially a powerful molecular marker for evolutionary studies of populations. However, a practical obstacle to its employment is the general problem of haplotype determination due to the common occurrence of heterozygosity in diploid organisms. We explore here a ‘consensus vote’ (CV) approach to this question, combining statistical haplotype reconstruction and experimental verification using as an example an indel‐free scnp DNA marker from the flanking region of a microsatellite locus of the migratory locust. The raw data comprise 251‐bp sequences from 526 locust individuals (1052 chromosomes), with 71 (28.3%) polymorphic nucleotide sites (including seven triallelic sites) and 141 distinct genotypes (with frequencies ranging from 0.2 to 25.5%). Six representative statistical haplotype reconstruction algorithms are employed in our CV approach, including one parsimony method, two expectation–maximization (EM) methods and three Bayesian methods. The phases of 116 ambiguous individuals inferred by this approach are verified by molecular cloning experiments. We demonstrate the effectiveness of the CV approach compared to inferences based on individual statistical algorithms. First, it has the unique power to partition the inferrals into a reliable group and an uncertain group, thereby allowing the identification of the inferrals with greater uncertainty (12.7% of the total sample in this case). This considerably reduces subsequent efforts of experimental verification. Second, this approach is capable of handling genotype data pooled from many geographical populations, thus tolerating heterogeneity of genetic diversity among populations. Third, the performance of the CV approach is not influenced by the number of heterozygous sites in the ambiguous genotypes. Therefore, the CV approach is potentially a reliable strategy for effective haplotype determination of nuclear DNA markers. Our results also show that rare variations and rare inferrals tend to be more vulnerable to inference error, and hence deserve extra surveillance.
Effect of GPI anchor moiety on the immunogenicity of DNA plasmids encoding the 19‐kDa C‐terminal portion of Plasmodium falciparum MSP‐1
Authors: LI G. , BASAGOUDANAVAR S. H. , GOWDA D. C.
Published: March 2008

The glycosylphosphatidylinositol (GPI)‐anchored Plasmodium falciparum merozoite surface protein 1 (MSP‐1) is a widely studied malaria vaccine candidate. The C‐terminal 19‐kDa portion of MSP‐1 (MSP‐119) is of particular interest because this polypeptide moiety remains bound to the parasite even after erythrocyte invasion, while the remainder of MSP‐1 is shed during invasion. Studies have shown that antibodies against MSP‐119 inhibit merozoite invasion of erythrocytes efficiently, and that MSP‐119 produces protective immunity in mice and monkeys. To investigate the efficacy of MSP‐119 DNA vaccine and role of GPI anchor moiety in the immunogenicity of MSP‐119, we constructed expression vectors that produce MSP‐119 as either secretory or GPI‐anchored polypeptide. Both constructs efficiently expressed MSP‐119 in transfected HEK‐293 cells. While the recombinant plasmid lacking GPI anchor signal sequence expressed MSP‐119 mainly as secreted polypeptide, that containing GPI anchor signal sequence produced GPI‐anchored MSP‐119 on cell surface. In immunized mice, both constructs produced substantial levels of MSP‐119‐specific IgG1, IgG2a, IgG2b, IgG3, IgA and IgM antibodies. In both cases, the IgG1 level was significantly higher than other isotypes. Interestingly, the plasmid containing GPI anchor signal sequence produced significantly higher levels of IgG2a and IgG2b than the plasmid that lacks GPI signal sequence.
Experimental evidence for diel variations of the carbon isotope composition in leaf, stem and phloem sap organic matter in Ricinus communis
Authors: GESSLER ARTHUR , TCHERKEZ GUILLAUME , PEUKE ANDREAS D. , GHASHGHAIE JALEH , FARQUHAR GRAHAM D
Published: March 2008

Carbon isotope fractionation in metabolic processes following carboxylation of ribulose‐1,5‐bisphosphate (RuBP) is not as well described as the discrimination during photosynthetic CO2 fixation. However, post‐carboxylation fractionation can influence the diel variation of δ13C of leaf‐exported organic matter and can cause inter‐organ differences in δ13C. To obtain a more mechanistic understanding of post‐carboxylation modification of the isotopic signal as governed by physiological and environmental controls, we combined the modelling approach of Tcherkez et al., which describes the isotopic fractionation in primary metabolism with the experimental determination of δ13C in leaf and phloem sap and root carbon pools during a full diel course. There was a strong diel variation of leaf water‐soluble organic matter and phloem sap sugars with relatively 13C depleted carbon produced and exported during the day and enriched carbon during the night. The isotopic modelling approach reproduces the experimentally determined day–night differences in δ13C of leaf‐exported carbon in Ricinus communis. These findings support the idea that patterns of transitory starch accumulation and remobilization govern the diel rhythm of δ13C in organic matter exported by leaves. Integrated over the whole 24 h day, leaf‐exported carbon was enriched in 13C as compared with the primary assimilates. This may contribute to the well‐known – yet poorly explained – relative 13C depletion of autotrophic organs compared with other plant parts. We thus emphasize the need to consider post‐carboxylation fractionations for studies that use δ13C for assessing environmental effects like water availability on ratio of mole fractions of CO2 inside and outside the leaf (e.g. tree ring studies), or for partitioning of CO2 fluxes at the ecosystem level.
Analysis of gene transcript profiling and immunobiology in Shetland sheepdogs with dermatomyositis
Authors: Wahl Jacquelyn M. , Clark Leigh Anne , Skalli Omar , Ambrus Andy , Rees Christine A. , Mansell Joanne L. , Murphy Keith E.
Published: March 2008

Dermatomyositis (DM) is a canine and human inflammatory disease of the skin and muscle that is thought to be autoimmune in nature. In dogs, DM occurs most often in the rough collie and Shetland sheepdog. Characteristic skin lesions typically develop on the face, ears, tail, and distal extremities. The severity of lesions varies and is thought to increase with stressful stimuli. Previous studies in the collie suggest that DM is inherited in an autosomal dominant fashion with incomplete penetrance. The work presented here concerns gene transcripts profiling and immunobiology of DM in the Shetland sheepdog. Gene transcript profiles were generated for affected and normal skin using a canine‐specific oligonucleotide array having 49,929 probe sets. Two‐hundred and eight‐five gene transcripts, many of which are involved in immune function, were found to be differentially regulated in these tissues. Also reported are Western blot, immunohistochemistry, and immunofluorescence analyses which showed that staining patterns with sera from normal and affected dogs are quite similar. While our work suggests that canine DM is a disease that may be immune mediated, it did not detect the production of specific disease‐associated autoantibodies.
Prevalence and clinical signs of avipoxvirus infection in falcons from the Middle East
Authors: Tarello Walter
Published: March 2008

The prevalence, cutaneous manifestations and concurrent clinical signs of avipoxvirus infection in 3706 falcons in two Middle Eastern countries are reported. Diagnosis was based on evidence of typical ‘dry’ skin lesions on featherless parts of the body and microscopic detection of Bollinger bodies in epithelial cells. Avipoxvirus was isolated from one representative case. Overall prevalence of cutaneous changes due to avipoxvirus infection did not differ significantly between Kuwait (2.7%) and Dubai (2.3%), although pox lesions were more prevalent on the feet of birds from Kuwait (67.4% vs. 50%) and more common on the eyelids of birds from Dubai (45.6% vs. 30.4%). Foot lesions were always present in birds with multiple infection sites. Some birds from Dubai had severe infection associated with weight loss, anorexia, lethargy, vomiting, central nervous system involvement and ultimately death.