bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of the pseudolysogenic response in slowly growing cells of Pseudomonas aeruginosa
Authors: Ripp Steven , Miller Robert V.
Published: June 2009

Pseudolysogeny is an environmental condition in which the starved bacterial cell coexists in an unstable relationship with infecting viral genomes. As nutrients are supplied to the bacterium, the pseudolysogens resolve into either true lysogeny or active production of virions. The direct result of pseudolysogenic relationships is an extension of the effective phage half-lives in natural environments. In this paper a continuous culture model of interactions between bacterial host organisms and bacteriophages leading to pseudolysogeny is presented. The pseudolysogenic state was found to depend on the concentration of nutrients available to the host. As cells became more starved, the frequency of pseudolysogens increased. The dependence on overall nutrient concentration was more dramatic than the variation in the generation time (chemostat turnover time) of the host. Thus, it appears that pseudolysogeny is a legitimate strategy for environmental bacteriophages to adapt to survive periods of starvation of their host organisms. Consideration of pseudolysogeny as a survival strategy is important to the development of any comprehensive model of host-bacteriophage relationships in natural environments.
Cytochalasin D interferes with contractile actin ring and septum formation in Schizosaccharomyces japonicus var. versatilis
Authors: Gabriel Miroslav , Horký Drahomír , Svoboda Augustin , Kopecká Marie
Published: June 2009

The cells ofSchizosaccharomyces japonicusvar.versatilisresponded to the presence of cytochalasin D (CD), an inhibitor of actin polymerization, by the disappearance of contractile actin rings (ARs) that had already formed and by inhibition of new ring formation. Actin cables disappeared. Actin patches remained preserved and became co-localized with regions of actual cell wall formation (at cell poles and at the site of septum development). Removal of the AR arrested formation of the primary septum and led to the production of aberrant septum protrusions in that region. Nuclear division was accomplished in the presence of CD but new ARs were not produced. The wall (septum) material was deposited in the form of a wide band at the inner surface of the lateral cell wall in the cell centre. This layer showed a thin fibrillar structure. The removal of CD resulted in rapid formation of new ARs in the equatorial region of the cells. This implies that the signal for AR localization was not abolished either by CD effects or by removal of an AR already formed. Some of the newly developed ARs showed atypical localization and orientation. In addition, redundant, subcortically situated actin bundles were produced. The removal of CD was quickly followed by the development of primary septa co-localized with ARs. Wall protrusions occurred co-localized with the redundant actin bundles. If these were completed in a circle, redundant septa developed. The AR is a mechanism which, in time and space, triggers cytokinesis by building a septum sequentially dependent on the AR. Aberrant septa were not capable of separating daughter cells. However, non-separated daughter cells subsequently gave rise to normal cells.
A hydrophobin (ABH3) specifically secreted by vegetatively growing hyphae of Agaricus bisporus (common white button mushroom)
Authors: Lugones Luis G. , Wös Han A. B , Wessels Joseph G. H
Published: June 2009

Aerial mycelium and hyphal strands of Agaricus bisporus, strain U1, exhibited a rodlet pattern at their surfaces characteristic for assembled class I hydrophobins. An SDS-insoluble/trifluoroacetic-acid-soluble fraction from strands was found to contain one abundant protein with an apparent molecular mass on gel of 19 kDa. Two sequences for this protein (ABH3), typical of class I hydrophobins, could be deduced by sequencing cDNA clones obtained by RT-PCR. The two forms of the protein could be assigned to different alleles present in the two homokaryons that constitute the heterokaryotic U1 strain. ABH3 displays all the in vitro properties of a typical class I hydrophobin such as SC3 from Schizophyllum commune but is not glycosylated or otherwise post-translationally modified because the molecular mass values deduced from the amino acid sequence (9228 and 9271 Da) and derived from mass spectrometry were in good agreement. The ABH3 transcript was found to be present in the vegetative mycelium of both primary and secondary mycelium but not in the fruiting bodies, whereas the reverse was found for the ABH1 hydrophobin. Using an S. commune mutant with a disrupted SC3 gene it was found that ABH3 can substitute for SC3 in inducing formation of aerial hyphae, suggesting a role of ABH3 in the emergence of aerial hyphae and strands in A. bisporus.
Airway hyper-responsiveness to neurokinin A and bradykinin following Mycoplasma pneumoniae infection associated with reduced epithelial neutral endopeptidase
Authors: Tamaoki Jun , Chiyotani Atsushi , Tagaya Etsuko , Araake Minako , Nagai Atsushi
Published: June 2009

To determine whether mycoplasma infection produces airway hyper-responsiveness to tachykinins and bradykinin and, if so, to elucidate the role of neutral endopeptidase (NEP), isolated hamster tracheal segments were studied under isometric conditionsin vitro.Nasal inoculation withMycoplasma pneumoniaepotentiated contractile responses to neurokinin A and bradykinin, causing a leftward shift of the dose-response curves to a lower concentration by 1 log unit for each agonist, whereas there was no response with acetylcholine. Pretreatment of tissues with the NEP inhibitor phosphoramidon augmented neurokinin A- and bradykinin-induced contractions in saline-treated control tissues, but did not further potentiate the responsiveness inM. pneumoniae-infected tissues. NEP activity in the tracheal epithelium, but not in epithelium-denuded tissues, was decreased in infected animals. These results suggest thatM. pneumoniaeinfection causes airway bronchoconstrictor hyper-responsiveness to neurokinin A and bradykinin and that this effect may be associated with an inhibition of epithelial NEP activity.
Anaerobic metabolism in Bacillus licheniformis NCIB 6346
Authors: Shariat Parvin , Mitchell Wilfrid J. , Boyd Alan , Priest Fergus G.
Published: June 2009

The products of anaerobic metabolism of glucose and its derivatives sorbitol, gluconate and glucuronate by Bacillus licheniformis have been determined by proton NMR. Glucose was fermented through mixed-acid fermentation pathways to acetate, 2,3-butanediol, ethanol, formate, lactate, succinate and pyruvate. However, the bacterium was incapable of fermenting the three glucose derivatives. When B. licheniformis cells were incubated anaerobically with glucose in the presence of nitrate, the reduced products and formate did not appear and acetate was formed as the major metabolite. Growth and formation of acetate was also observed when B. licheniformis cells were incubated anaerobically with each of the three glucose derivatives, in the presence of nitrate. A formate-nitrate oxido-reductase system was induced under anaerobic conditions, with increased activities when nitrate was added to the anaerobic growth medium. However no activity was detected when cell; were grown in the presence of molecular oxygen. Formate-nitrate oxido-reductase activity was absent in chlorate-resistant mutants isolated spontaneously or following Tn917 insertional mutagenesis. The spontaneous mutants fermented glucose in the presence of nitrate suggesting that they were incapable of nitrate respiration, due to a deficiency in one or more components of the formate-nitrate oxido-reductase system. Two insertional mutants exhibited elevated β-galactosidase activity when grown in the presence of nitrate.
Phage infection, transfection and transformation of Mycobacterium avium complex and Mycobacterium paratuberculosis
Authors: Foley-Thomas Ellen M. , Whipple Diana L. , Bermudez Luiz E. , Barletta Raul G.
Published: June 2009

Mycobacterium aviumcomplex strains andMycobacterium paratuberculosisare closely related intracellular pathogens affecting humans and animals.M. aviumcomplex infections are a leading cause of morbidity and mortality in AIDS patients, andM. paratuberculosisis the agent of Johne's disease in ruminants. Genetic manipulation of these micro-organisms would facilitate the understanding of their pathogenesis, the construction of attenuated vaccine strains and the development of new drugs and treatment methods. This paper describes the replication of mycobacterial shuttle phasmids and plasmids, and the expression of the firefly luciferase reporter gene inM. aviumcomplex andM. paratuberculosis. The mycobacteriophage TM4 propagated onM. smegmatisorM. paratuberculosisplaqued at the same efficiency on these two mycobacterial hosts. Screening ofM. aviumcomplex andM. paratuberculosisclinical isolates with TM4-derived luciferase reporter phages demonstrated that the majority of these isolates were susceptible to TM4. Conditions for introduction of DNA were determined by transfection ofM. paratuberculosiswith TM4 DNA and applied to isolate kanamycin-resistant transformants ofM. aviumcomplex andM. paratuberculosiswithEscherichia coli-Mycobacteriumshuttle plasmids. Recombinant plasmids were recovered from transformants without apparent loss of DNA sequences. These results provide the basis for the genetic manipulation of these pathogenic mycobacterial species.
Molecular characterization of katA from Campylobacter jejuni and generation of a catalase-deficient mutant of Campylobacter coli by interspecific allelic exchange
Authors: Grant Kathleen A. , Park Simon F.
Published: June 2009

A gene encoding catalase (hydrogen-peroxide: hydrogen-peroxide oxidoreductase; EC 1.11.1.6) from Campylobacter jejuni was cloned by functional complementation of a catalase-deficient mutant of Escherichia coli. The catalase structural gene, designated katA, was assigned by subcloning and its nucleotide sequence determined. The deduced protein product of 508 amino acids, which had a calculated molecular mass of 58346 Da, was found to be structurally and enzymically similar to hydrogen-peroxidases from other bacterial species. The region of DNA containing the structural catalase gene was disrupted by insertion of a tetracycline-resistance marker and the modified sequence then introduced into a strain of Campylobacter coli via natural transformation. Genetic and enzymic analyses of a tetracycline-resistant C. coli transformant confirmed that catalase-deficient mutants had arisen via interspecific allelic exchange. Compared to the isogenic parental strain the mutant was more sensitive to killing by H2O2.
Molecular systematics of the genus Pleurotus: analysis of restriction polymorphisms in ribosomal DNA
Authors: Béatrice Lraçabal , Georgios Zervakis
Published: June 2009

Part of the nuclear ribosomal DNA unit ofPleurotus cornucopiae, including most of the intergenic sequences, was used as a probe to hybridize with DNA from elevenPleurotustaxa (29 isolates), digested with nine restriction endonucleases. For all digests, a high level of rDNA heterogeneity between and within species was detected, which is in agreement with the phenetic variability already reported in previous studies onPleurotustaxa. Numerical analysis of the results, performed by use of two different tree-making methods, clearly distinguished among well-defined species, i.e.P. dryinus, P. eryngiiandP. flabellatus, which presented large phenetic distances with the rest of the taxa tested.P. abalonus, despite morphological similarity and interfertility withP. cystidiosus, appears to be a discrete taxon. Although they showed relative affinity,P. cornucopiae, P. columbinusandP. ostreatuspresented large distances among their representative isolates, supporting the idea that they correspond to distinct taxa. All strains ofP. pulmonarius, P. sajor-cajuandP. sapidushaving small phenetic distances were closely positioned on dendrograms; in relation to results from recent interfertility and isozyme studies, these results support the common genetic background ofP. pulmonariusandP. sajor-caju; the position ofP. sapidusremains controversial. Furthermore, the rDNA analysis identified ten fragments suitable for species identification: eight allowed the characterization of five taxa (P. cornucopiae. P. ostreatus, P. sajor-caju, P. abalonusandP. columbinus) and two distinguished among clusters including related taxa. By a combination of just two restriction enzymes, the rDNA probe used seems to be the appropriate tool for both varietal characterization and protection of commercially valuable strains.
A new Myxococcus xanthus gene cluster for the biosynthesis of the antibiotic saframycin Mx1 encoding a peptide synthetase
Authors: Pospiech Andreas , Cluzel Bernard , Bietenhader Jürg , Schupp Thomas
Published: June 2009

The gene cluster for the biosynthesis of the heterocyclic quinone antibiotic saframycin Mx1 of Myxococcus xanthus DM504/15 was inactivated and tagged by Tn5 insertions. The tagged genes were cloned in Escherichia coli and used to select overlapping cosmid clones spanning 58 kb of the M. xanthus genome. Gene disruption experiments defined a ≥ 18 kb contiguous DNA region involved in saframycin biosynthesis. Sequencing of part of this region revealed a large ORF containing two 600-amino-acid domains with similarity to peptide synthetase amino-acid-activating sequences, suggesting that saframycin Mx1 is synthesized by a nonribosomal multienzyme complex, similar to other bioactive peptides.
Metabolic engineering in Escherichia coli: lowering the lipoyl domain content of the pyruvate dehydrogenase complex adversely affects the growth rate and yield
Authors: Dave Emma , Guest John R. , Attwood Margaret M.
Published: June 2009

Isogenic strains of Escherichia coli W3110 containing pyruvate dehydrogenase complexes with three (wild-type), two or one lipoyl domains per lipoate acetyltransferase (E2p) chain, were constructed. The maximum growth rates (max) for batch cultures growing in minimal medium containing different carbon sources showed that reducing the number of lipoyl domains adversely affects cell growth. The lower max value of the mutant containing one lipoyl domain per E2p chain was restored by the presence of compatible multicopy plasmids encoding PDH complexes with either one or three lipoyl domains per E2p chain. In glucose-limited chemostat cultures the protein contents of all strains were similar and substrate carbon was totally accounted for in the biomass and CO2 produced. However, the carbon efficiencies (percentage carbon conversion to biomass) were significantly lower when the lipoyl domain content of the E2p subunit was reduced from three to one. Similarly, the cellular maintenance energy (m
e) and the maximum growth yield (Y
max) were lower in bacteria containing PDH complexes with fewer than three lipoyl domains per E2p chain. Wild-type values were restored by supplementing the medium with either casamino acids (0-01%) or acetate (up to 0-1 mM). The lower growth efficiencies of the mutants were further confirmed in competition experiments where equal numbers of genetically marked (NalR) mutant and wild-type bacteria were used to inoculate glucose-limited chemostat cultures (dilution rate 0-075 h−1). The mutants with one or two lipoyl domains per E2p chain were washed out, whereas in controls, the initial ratio of wild-type (Nal) to reconstructed wild-type (NalR) bacteria was maintained over 50 generations.
Powerful methods to establish chromosomal markers in Lactococcus lactis: an analysis of pyrimidine salvage pathway mutants obtained by positive selections
Authors: Martinussen Jan , Hammer Karin
Published: June 2009

Using different 5-fluoropyrimidine analogues, positive selection procedures for obtaining mutants blocked in pyrimidine and purine salvage genes of Lactococcus lactis were established. Strains lacking the following enzyme activities due to mutations in the corresponding genes were isolated: uracil phosphoribosyltransferase (upp), uridine/cytidine kinase (udk), pyrimidine nucleoside phosphorylase (pdp), cytidine/deoxycytidine deaminase (cdd), thymidine kinase (tdk) and purine nucleoside phosphorylase (pup). Based on an analysis of the mutants obtained, the pathways by which L. lactis metabolizes uracil and the different pyrimidine nucleosides were verified. The substrate specificities of the different enzymes were determined. It was demonstrated that a single pyrimidine nucleoside phosphorylase accounts for the phosphorolytical cleavage of uridine, deoxyuridine and thymidine, and a single purine nucleoside phosphorylase has activity towards both the ribonucleoside and deoxyribonucleoside derivatives of adenine, guanine and hypoxanthine. No phosphorylase activity towards xanthosine appeared to be present. The selection procedures developed during this work may be employed in establishing markers on the chromosome of many related lactic acid bacteria.
Reduction of exogenous ferric iron by a surface-associated ferric reductase of Listeria spp.
Authors: Deneer Harry G. , Healey Vanessa , Boychuk Irene
Published: June 2009

The reduction of exogenous ferric iron by Listeria monocytogenes, a Gram-positive food-borne pathogen, was investigated. Using an assay incorporating the ferrous iron chelator ferrozine, we showed that intact cells of L. monocytogenes, when exposed to ferric iron, were able to rapidly reduce and solubilize the iron to the ferrous form. Reduction occurred only after direct contact between the bacteria and the iron source. A number of different ferric iron chelates, including transferrin and lactoferrin-bound iron, haemoglobin, ferritin, and iron complexed to siderophores, could be reduced. The ferric reductase activity was expressed by both reference strains and clinical isolates of L. monocytogenes and by all other species of Listeria, although significant quantitative differences were observed. In L. monocytogenes, the expression of ferric reductase was not affected by the growth phase of the bacteria nor by the presence or absence of iron in the growth medium. However, expression was greatly reduced in bacteria grown anaerobically and when cultured in media of reduced pH. In addition, bacteria grown at a cold temperature displayed greater ferric reductase activity than cells grown at higher temperatures. A surface-associated ferric reductase system may be one component of a general iron scavenging mechanism which can be used by Listeria growing in a variety of environments.
Genes and enzymes of the acetyl cycle of arginine biosynthesis in Corynebacterium glutamicum: enzyme evolution in the early steps of the arginine pathway
Authors: Sakanyan Vehary , Petrosyan Pavel , Lecocq Michèle , Boyen Anne , Legrain Christiane , Demarez Marc , Hallet Jean-Noël , Glansdorff Nicolas
Published: June 2009

A cluster of arginine biosynthetic genes of Corynebacterium glutamicum ATCC 13032, comprising argJ, argB and argD as well as part of argC and argF, has been cloned by heterologous complementation of an Escherichia coli argE mutant. The gene order has been established as argCJBDF by sequencing the entire 4.4 kb cloned DNA fragment. The C. glutamicum argB gene can be transcribed in E. coli cells from an internal promoter located in the coding part of the preceding argJ gene, whereas transcription of the argJ gene appears vector-dependent. Expression of the corynebacterial argB gene is repressed by arginine in the native host but not in recombinant E. coli cells. Feedback inhibition of the corresponding N-acetylglutamate kinase activity was observed both in cell extracts of C. glutamicum and in recombinant E. coli argB auxotrophic strains. Extracts of E. coli cells carrying cloned corynebacterial DNA display an ornithine acetyltransferase activity (encoded by argJ) which alleviates the acetylornithinase (encoded by argE) deficiency of the enterobacterial host. In contrast to Bacillus stearothermophilus ornithine acetyltransferase which also exhibits acetylglutamate synthase activity, C. glutamicum ornithine acetyltransferase appears monofunctional. ArgA and ArgB proteins from different sources share highly significant similarities. The evolutionary implications of these data are discussed.
The dnrM gene in Streptomyces peucetius contains a naturally occurring frameshift mutation that is suppressed by another locus outside of the daunorubicin-production gene cluster
Authors: Gallo Mark A. , Ward Joanne , Hutchinson C. R.
Published: June 2009

Summary: A 2.7 kb BamHI fragment of the daunorubicin biosynthetic cluster in Streptomyces peucetius ATCC 29050 was shown to contain two ORFs, dnrL and dnrM, whose deduced products exhibit a high sequence similarity to a number of glucose-1-phosphate thymidylyl transferases and TDP-D-glucose dehydratases, respectively. Although these genes were believed to be necessary for the synthesis of the deoxyaminosugar, daunosamine, a constituent of daunorubicin, the dnrM gene contains a frameshift in the DNA sequence that causes the premature termination of translation. A gene encoding another TDP-glucose 4,6-dehydratase, previously isolated from S. peucetius, was identified by PCR amplification of genomic DNA. The presence of this gene explains why a dnrM::aphll mutation did not block daunorubicin production.
Escherichia coli RNase II: characterization of the promoters involved in the transcription of rnb
Authors: Zilhão Rita , Plumbridge Jacqueline , Hajnsdorf Eliane , Régnier Philippe , Arraiano Cecília M.
Published: June 2009

Summary: The rnb gene encodes ribonuclease II (RNase II), one of the two major Escherichia coli exonucleases involved in mRNA degradation. In this paper, the rnb transcript is characterized regarding its promoter and terminator regions. The combined results from S1 nuclease protection analysis, DNase I footprinting and gene fusions with IacZ have shown that rnb is expressed from two promoters. S1 nuclease protection analysis and DNA footprinting have shown that rnb has two promoters, P1 and P2. Transcriptional and translational IacZ reporter fusions, constructed to the rnb gene, revealed that P2, the rnb proximal promoter, is stronger than P1. However, P2 is not transcribed in vitro, suggesting that an additional factor is required in vivo. The 3' end of the rnb transcript mapped to a stem-loop structure immediately after the translated region.
Two chitin synthase genes from Ustilago maydis
Authors: Xoconostle-Cázares Beatriz , León-Ramirez Claudia , Ruiz-Herrera José
Published: June 2009

Summary: PCR was used to amplify fragments corresponding to CHS genes from Ustilago maydis, utilizing as primers oligonucleotides devised according to the conserved regions of fungal CHS genes. The PCR product was employed as a probe to screen a genomic library of the fungus. Two different CHS genes (Umchs1 and Umchs2) were thus identified in the positive clones recovered. Their sequence revealed high similarity with the CHS genes previously cloned from other fungi, especially in their central region. Alignment with the deduced protein sequences of all CHS genes reported up to date showed the existence of seven conserved domains. Transcripts from both genes were detected in the yeast and mycelial forms. In general, the transcripts from the Umchs1 gene appeared to be present at a higher level than the transcripts from the Umchs2 gene; the transcripts from both genes appeared to be more abundant in the mycelial form. Gene replacement of either gene and analysis of the resulting phenotype demonstrated that they are non-essential. Nevertheless, growth, chitin synthase activity levels, and chitin content of mycelial cells induced by cultivation in acidic media were all reduced in chs1 and chs2 mutants. However, mating, virulence and dimorphic behaviour were unaffected. Overall, the results indicate that the CHS1 and CHS2 genes encode products with redundant functions in U. maydis.
nuvA, An Aspergillus Nidulans Gene Involved in DNA Repair and Recombination, is a Homologue of Saccharomyces Cerevisiae RAD18 and Neurospora Crassa uvs-2
Authors: Iwanejko Lesley , Cotton Catherine , Jones Gary , Tomsett Brian , Strike Peter
Published: June 2009

A 40 kb genomic clone and 2·3 kb EcoRI subclone that rescued the DNA repair and recombination defects of the Aspergillus nidulans nuvA11 mutant were isolated and the subclone sequenced. The subclone hybridized to a cosmid in a chromosome-specific library confirming the assignment of nuvA to linkage group IV and indicating its closeness to bimD. Amplification by PCR clarified the relative positions of nuvA and bimD. A region identified within the subclone, encoding a C3HC4 zinc finger motif, was used as a probe to retrieve a cDNA clone. Sequencing of this clone showed that the nuvA gene has an ORF of 1329 bp with two introns of 51 bp and 60 bp. Expression of nuvA appears to be extremely low. The putative NUVA polypeptide has two zinc finger motifs, a molecular mass of 48906 Da and has 39% identity with the Neurospora crassa uvs-2 and 25% identity with the Saccharomyces cerevisiae RAD18 translation products. Although mutations in nuvA, uvs-2 and RAD18 produce similar phenotypes, only the nuvA11 mutation affects meiotic recombination. A role for nuvA in both DNA repair and genetic recombination is proposed.
Genetic transfer of amylovoran and stewartan synthesis between Erwinia amylovora and Erwinia stewartii
Authors: Bernhard Frank , Schullerus Dietlinde , Bellemann Peter , Nimtz Manfred , Coplin David L. , Geider Klaus
Published: June 2009

DNA fragments with ams genes of Erwinia amylovora and cps genes of Erwinia stewartii were transferred to exopolysaccharide (EPS)-deficient mutants of the other species. The resulting EPSs were characterized by sensitivity to EPS-dependent bacteriophages, staining with amylovoran-specific fluorescein-isothiocyanate-labelled lectin and chemical techniques, such as determination of the sugar composition and methylation analysis in order to distinguish between amylovoran and stewartan. Degradation by the stewartan-dependent phage ø-K9 was used to detect stewartan production, and staining with a lectin from Abrus precatorius detected amylovoran capsules. The patterns of sugar linkages were determined by methylation analysis. Stewartan contained a significantly higher glucose to galactose ratio than amylovoran and produced a characteristic signal from 6-linked glucose residues. By these criteria, most E. stewartii cps mutants displayed exclusively amylovoran synthesis when complemented with the ams cluster, and E. amylovora ams mutants complemented with E. stewartii cps genes produced stewartan. The complementation to an EPS-positive phenotype may require most genes of the ams or the cps operon. An exception was an E. stewartii cpsK mutant that made predominantly stewartan when complemented with the ams cosmid. IR spectra showed that both amylovoran and stewartan were acylated when synthesized in E. amylovora, but not in E. stewartii. The amylovoran-producing E. stewartii merodiploids regained virulence to corn seedlings when mucoidy was restored by the ams cluster, but the stewartan-producing E. amylovora ams-lcps
+ strains were weakly virulent on pear slices and avirulent on apple seedlings.
In vitro phagocytosis and survival of Streptococcus suis capsular type 2 inside murine macrophages
Authors: Brazeau C. , Gottschalk M. , Vincelette S. , Martineau-Doizé B.
Published: June 2009

In this study, data on phagocytosis of Streptococcus suis and its survival inside macrophages are presented. Mouse peritoneal macrophages were incubated in the presence of one of five different strains of S. suis capsular type 2: a virulent wild-type strain (1591), a non-capsulated non-virulent mutant strain (M2), a poorly capsulated non-virulent mutant strain (M42), a non-virulent capsulated strain (1330), and the wild-type reference (virulent) strain 5735. Opsonized or non-opsonized bacteria were incubated with macrophages in vitro and samples were obtained after 1 and 3 h incubation. Phagocytosis as well as live and dead intracellular organisms were determined by acridine orange and crystal violet staining. After 1 h incubation, non-opsonized virulent and non-virulent capsulated bacteria were poorly phagocytosed (by less than 7% of the macrophages), whereas the non-capsulated non-virulent mutant strain was highly phagocytosed (by more than 68% of the macrophages). The M42 mutant strain was more phagocytosed than the capsulated strains but less than the non-capsulated M2 mutant strain (35%). In contrast, a higher percentage of live bacteria was observed inside macrophages for the capsulated strains (1591 and S735) than for the non- or poorly capsulated mutant strains (M2 and M42). Opsonization of bacteria with rabbit serum or heat-inactivated rabbit serum significantly increased phagocytosis. For every opsonized strain, after 3 h incubation, the percentage of live bacteria within macrophages was considerably lower than the corresponding non-opsonized strains. In conclusion, the capsule of S. suis type 2 appears to act as an important anti-phagocytic factor. However, virulent capsulated non-opsonized strains can be phagocytosed by mouse peritoneal macrophages within which they appear to survive for at least 3 h. Serum factors other than complement increase not only phagocytosis but also intracellular killing of S. suis of both capsulated and non-capsulated strains.
Sizing chromosomes and megaplasmids in haloarchaea
Authors: López-García P. , Amils R. , Antón J.
Published: June 2009

PFGE was used for the genomic analysis of different species and strains belonging to four out of the six recognized haloarchaeal (halobacterial) genera. All of them were found to carry one chromosome from 1.8-3 Mb, and usually several, but at least one, large plasmids of approximately 90-680 kb, which were detected in supercoiled and linear forms. From the data gathered, chromosomal size appears to be conserved at genus level, whereas plasmid composition and size seems to be subjected to certain variability.
Proline is biosynthesized from arginine in Staphylococcus aureus
Authors: Townsend David E. , Kaenjak Anisa , Jayaswal Radheshyam K. , Wilkinson Brian J.
Published: June 2009

Staphylococcus aureus NCTC 8325 exhibited a long lag phase (11 h) when inoculated into defined medium lacking proline, that could be shortened by increasing the concentration of arginine in the medium, or by supplying ornithine. Radioactivity from L-[14C]arginine, but not l-[14C]glutamate was incorporated into a spot with the chromatographic mobility of [14C]proline in the pool metabolites fraction. Selection for transposon Tn917-lacZ mutants impaired in arginine catabolism yielded four proline auxotrophs. Enzyme assays and precursor feeding experiments suggested that the major pathway for proline biosynthesis in S. aureus was from arginine via ornithine and Δ’-pyrroline 5-carboxylate, rather than from glutamate. Strain 8325 Pro+, a proline prototrophic variant obtained by cultivation of 8325 in the absence of proline, accumulated L-[14C]arginine from the medium at about eight times the rate of strain 8325, suggesting its response to proline starvation was to increase arginine uptake.
Assessment of herd protection against trachoma due to repeated mass antibiotic distributions: a cluster‐randomised trial
Authors: Reading Richard
Published: June 2009

.
 
House J. I.,
Ayele B.,
Porco T. C.,
Zhou Z.,
Hong K. C.,
Gebre T.,
Ray K. J.,
Keenan J. D.,
Stoller N. E. &
Whitcher J. P.
(
2009
)

,
373
,
1111
–
1118
.

Background Trachoma‐control programmes distribute oral azithromycin to treat the ocular strains of chlamydia that cause the disease and to control infection. Theoretically, elimination of infection is feasible if untreated individuals receive an indirect protective effect from living in repeatedly treated communities, which is similar to herd protection in vaccine programmes. We assessed indirect protection against trachoma with mass azithromycin distributions.

Methods In a cluster randomized trial, 24 subkebeles (government‐defined units) in Amhara, Ethiopia, were randomized, with use of a simple random sample, to distribution four times per year of single‐dose oral azithromycin to children aged 1–10 years (12 subkebeles, 4764 children), or to delayed treatment until after the study (control; 12 subkebeles, 6014 children). We compared the prevalence of ocular chlamydial infection in untreated individuals 11 years and older between baseline and 12 months in the treated subkebeles, and at 12 months between the treated and control subkebeles. Healthcare and laboratory personnel were blinded to study group. Analysis was intention to treat. The study is registered with clinicaltrials.gov, number NCT00322972.

Findings At 12 months, 637 children aged 1–10 years and 561 adults and children aged 11 years and older were analysed in the children‐treated group, and 618 and 550, respectively, in the control group. The mean prevalence of infection in children decreased from 48.4% (95% CI 42.9–53.9) to 3.6% (0.8–6.4) after four mass treatments. At 12 months, the mean prevalence of infection in the untreated age group (≥11 years) was 47% (95% CI 33–57) less than baseline (P= 0.002), and 35% (95% CI 1–57) less than that in untreated communities (P= 0.04).

Interpretation Frequent treatment of children, who are a core group for transmission of trachoma, could eventually eliminate infection from the entire community. Herd protection is offered by repeated mass antibiotic treatments, providing a strategy for elimination of a bacterial disease when an effective vaccine is unavailable.
Methane oxidation kinetics differ in European beech and Norway spruce soils
Authors: Degelmann D. M. , Borken W. , Kolb S.
Published: June 2009

Coniferous forest soils often consume less of the greenhouse gas methane (CH4) than deciduous forest soils. The reasons for this phenomenon have not been resolved. It might be caused by differences in the diffusive flux of CH4 through the organic layer, pH or different concentrations of potentially inhibitory compounds. Soil samples were investigated from three adjacent European beech (Fagus sylvatica) and Norway spruce (Picea abies) stands in Germany. Maximal CH4 oxidation velocities (Vmax(app)) and Michaelis Menten constants (KM(app)), retrieved from intact soil cores at constant CH4 concentrations, temperature and matric potential, were twice as great in beech as in spruce soils. Also atmospheric CH4 oxidation rates measured in homogenized soil samples displayed the same trend. Greatest atmospheric CH4 oxidation rates were detected in the Oa horizon or in the upper 5 cm of the mineral soil. In contrast to the beech soils, the Oa horizon of the spruce soils consumed no CH4. A differential effect due to divergent diffusive flux through the litter layer was not found. pH and ammonium concentration were similar in samples from both forest soil types. Ethylene accumulation in all soils was negligible under oxic conditions. These collective results suggest that the different atmospheric CH4 uptake by beech and spruce soils is caused by different CH4 oxidizing capacities of methanotrophic communities in the Oa horizon and top mineral soil.
The contribution of Toll‐like receptor 2 to the innate recognition of a Leishmania infantum silent information regulator 2 protein
Authors: Silvestre Ricardo , Silva Ana M. , Cordeiro‐da‐Silva Anabela , Ouaissi Ali
Published: June 2009

We have characterized a Leishmania protein belonging to the silent information regulator 2 (SIR2) family [SIR2 related protein 1 (SIR2RP1)] that might play an immunoregulatory role during infection through its capacity to trigger B‐cell effector functions. We report here that SIR2RP1 leads to the proliferation of activated B cells, causing increased expression of major histocompatibility complex (MHC) II and the costimulatory molecules CD40 and CD86, which are critical ligands for T‐cell cross‐talk during the development of adaptive immune responses. In contrast, B cells isolated from Toll‐like receptor 2 (TLR2) knockout mice were unable to respond to the SIR2RP1 stimulus. Similarly, SIR2RP1 induced the maturation of dendritic cells (DCs) in a TLR2‐dependent manner with the secretion of pro‐inflammatory cytokines [interleukin (IL)‐12 and tumour necrosis factor (TNF)‐α] and enhanced the costimulatory properties of DCs. Nevertheless, immunization assays demonstrated that TLR2‐deficient mice were able to mount a specific humoral response to SIR2RP1. Interestingly, further investigations showed that macrophages were activated by SIR2RP1 even in the absence of TLR2. Therefore, a different type of interplay between SIR2RP1 and the major antigen‐presenting cells in vivo could explain the immune response observed in TLR2‐deficient mice. Together, these results demonstrate that TLR2 signalling contributes to SIR2RP1 recognition by innate immune host cells.
Childhood trauma as a predictor of eating psychopathology and its mediating variables in patients with eating disorders
Authors: Kong Seongsook , Bernstein Kunsook
Published: June 2009

Aim.  The aims of this study were to determine whether specific forms of childhood trauma predict eating psychopathologies and to investigate the mediating effects of the psychological symptoms of depression and obsessive‐compulsion between childhood trauma and eating psychopathologies in patients with eating disorders.

Background.  The highest probability of poor treatment outcomes in patients with eating disorders has been observed in those who experienced childhood trauma. Therefore, researchers are now examining whether childhood trauma should be considered a risk factor for eating psychopathology, but childhood traumatic experiences as predictors of eating psychopathology and their mediating variables has not been investigated sufficiently with this clinical population.

Design.  Survey.

Methods.  The subjects were 73 Korean patients with eating disorders. The Childhood Trauma Questionnaire, Eating Disorder Inventory‐2, Beck Depression Inventory and Maudsley Obsessional‐Compulsive Inventory were used to assess self‐reported childhood trauma in five domains (emotional abuse, physical abuse, sexual abuse, emotional neglect and physical neglect), eating psychopathology, depression and obsessive‐compulsion. Stepwise multiple regression analyses were used to explore whether these childhood traumatic experiences predict eating psychopathology and mediation analyses were conducted according to Baron and Kenny’s guidelines.

Results.  Emotional abuse, physical neglect and sexual abuse were found to be significant predictors of eating psychopathology. We also found that depression fully mediated the association between some forms of childhood trauma and eating psychopathology, while obsessive‐compulsion did not mediate this association.

Conclusions.  Future interventions for patients with eating disorders should focus on assessing the possibility of childhood trauma, especially in those patients with poor treatment outcomes. In addition, whether or not traumatised individuals exhibit depression is a more important predictor of eating psychopathology than the traumatic experience itself.

Relevance to clinical practice.  Early intervention for childhood trauma and depression might contribute to preventing eating disorders in traumatised individuals.
Impact of nurses clothing on anxiety of hospitalised children
Authors: Roohafza Hamidreza , Pirnia Afsaneh , Sadeghi Masoumeh , Toghianifar Nafiseh , Talaei Mohammad , Ashrafi Mahmood
Published: June 2009

Aim.  To investigate anxiety levels in two groups of children exposed to nurses with white vs. coloured clothing in a university hospital in Iran.

Background.  Hospitalisation causes anxiety in children and it is documented that nurses have an important role in alleviating children’s distress and anxiety. Nurses characteristics, including their clothing is a factor that affects quality of care through child–nurse relationship.

Design.  Clinical trial.

Methods.  Children (n = 92) aged 7–15 years old hospitalised for 3–5 days in paediatric surgery ward were exposed to nurses in white or coloured clothing. Children’s anxiety was assessed on admission and at discharge using Revised Children’s Manifest Anxiety Scale.

Results.  Children exposed to white nursing uniforms showed higher anxiety levels compared with children exposed to coloured nursing clothing (p ≤ 0·05). Besides coloured nursing clothing, female sex, age >11 years old (guidance school) and living in families with more than four members were predictors of lower global anxiety scores.

Conclusion.  Providing a child‐friendly environment through colourful nursing clothing can promote nurses’ relationship with hospitalised children. This can satisfy children’s expectations of the nursing care and alleviates the need for meeting ideals of nursing care through wearing a white nursing uniform provided that standards of nursing care are favoured.

Relevance to clinical practice.  Using colourful nursing clothing in paediatric wards reduces anxiety as a psychological parameter which delays improvement and provides a child‐friendly environment that helps promotion of quality of nursing care.
Case fatality of SARS in mainland China and associated risk factors
Authors: Jia Na , Feng Dan , Fang Li‐Qun , Richardus Jan Hendrik , Han Xiao‐Na , Cao Wu‐Chun , De Vlas Sake J.
Published: June 2009

Objective To analyse the case fatality ratio (CFR) and its risk factors for severe acute respiratory syndrome (SARS) in mainland China by using a comprehensive dataset of all probable cases.

Methods The data of all probable SARS cases were derived from the Infectious Disease Reporting System of the Center of Diseases Control and Hospital Information Systems, during the 2003 epidemic in mainland China. The definition of probable SARS case was consistent with the definition for clinically confirmed SARS issued by the Ministry of Health of the People’s Republic of China. We performed univariate and multivariate logistic regression analysis to determine the association of CFR with age, sex, residence location, occupation, the period of the epidemic and the duration from symptom onset to admission into hospital.

Results The overall CFR was 6.4% among 5327 probable SARS cases in mainland China. Old age, being a patient during the early period of a local outbreak, and being from Tianjin led to a relatively higher CFR than young age, late stage of a local outbreak and cases from Beijing. Guangdong Province resulted in an even lower CFR compared with Beijing.

Conclusions Because of their deteriorated health status and apparent complications, SARS patients aged >60 years had a much higher risk of dying than younger patients. At the early stage of local outbreaks, lack of experience in patient care and perhaps treatment also led to a relatively higher CFR. The Tianjin SARS outbreak happened mainly within a hospital, leading to a high impact of co‐morbidity. The relatively young age of the cases partly explains the low CFR in mainland China compared with other countries and areas affected by SARS.
Geographical spread of SARS in mainland China
Authors: Fang Li‐Qun , De Vlas Sake J. , Feng Dan , Liang Song , Xu You‐Fu , Zhou Jie‐Ping , Richardus Jan Hendrik , Cao Wu‐Chun
Published: June 2009

Objectives  To describe the spatiotemporal diffusion of the severe acute respiratory syndrome (SARS) epidemic in mainland China, and to analyse the spatial pattern of SARS transmission from the Beijing epicentre to its neighbouring areas.

Methods  Probable SARS cases occurring between November 2002 and May 2003 in mainland China were compiled from different sources and geo‐coded into a geographical information database based on onset location. Spatial analyses including kernel density estimation, and spatial statistical and tracking analyses were performed to characterise the spatiotemporal distribution of SARS cases based on onset location/date. SARS cases that got infected in Beijing but were reported in three provinces surrounding Beijing were mapped, and logistic regression using a ‘case–control’ design at the county level was performed to analyse the impact of travel‐related risk factors in the diffusion pattern.

Results  The SARS epidemic in mainland China spanned a large geographical extent but clustered in two areas: first in Guangdong Province, and about 3 months later in Beijing with its surrounding areas in Shanxi Province, Inner Mongolia Autonomic Region, Hebei Province and Tianjin. Counties in the neighbourhood of Beijing that were crossed by a national highway or inter‐provincial freeway showed the highest risk of acquiring SARS infections, even after correction for population density and medical staff density. Being intersected by a railway did not significantly associate with risk of SARS.

Conclusions  This study provides the first complete documentation of the spatial and temporal characteristics of the SARS epidemic in mainland China. Our analyses confirmed that SARS had benefited from national highways and inter‐provincial freeways for its spread from epicentres to neighbouring areas, whereas trains showed no significant association. This knowledge may be important for the control of re‐emerging SARS, or other future emerging human‐to‐human transmittable infections.
The extent and prevailing shape of spatial relationships in Polish variety testing trials on wheat
Authors: Pilarczyk W.
Published: June 2009

Independence of observations is one of the basic assumptions of the analysis of variance. Performed randomizations prevent results from being biased in cases when independence is violated. The objective of the present paper is to find out the predominant shape of spatial relationships in Polish wheat variety testing trials. One of the possibilities is to apply some geo‐statistical method (Cressie Noel 1993, Grondona and Cressie 1991). Such an approach is used in this paper. Using the results of nearly 200 trials on wheat varieties, conducted either in generalized lattice (GL) designs (Patterson and Hunter 1983) or in incomplete split‐block designs, the empirical values of semivariance have been calculated. Residuals were computed from a model with fixed effects for varieties and replicates, ignoring incomplete blocks, then 10 different geo‐statistical models have been fitted to empirical semivariances. With spatial models convergence problems occurred in some cases. The linear and bounded‐linear models were the ones most often successfully fitted. Inclusion of revealed relationships into classical models for incomplete blocks did not improve substantially the effectiveness of analyses.
Localized globalization: A multi‐local, multivariate investigation of quotative be like1
Authors: Buchstaller Isabelle , D'Arcy Alexandra
Published: June 2009

We conduct a multi‐local, multivariate analysis of be like in comparable datasets from three discontinuous geographic settings (the U.S.A., England, and New Zealand). Previously, comparative cross‐variety analysis of this form has been fundamentally hampered by key methodological differences. A methodologically coherent analysis reveals that the ‘classic factors’ (Tagliamonte and D’Arcy 2007: 203) grammatical person and content of the quote, as well as the effect of mimesis, are transferred to the receptor variety, albeit with varying degrees of completeness. Other conditioning factors are particularized to the local system into which be like is adopted, which leads us to define its spread as a case of weak transfer. We suggest that there are at least two explanations for this finding: (1) global innovations must be considered in light of the local systems into which they are adopted; and (2) the form and amount of contact must be correlated with respect to the knowledge transfer they allow.