bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical-genetic map of the erythromycin-producing organism Saccharopolyspora erythraea
Authors: Reeves Andrew R. , Post David A. , Vanden Boom Thomas J
Published: June 2009

A physical map of the chromosome of the erythromycin-producing actinomycete Saccharopolyspora erythraea NRRL 2338 has been constructed using the restriction enzymes Asel and Dral. The map was constructed by a variety of methods including linking clone analysis, cross-hybridizations using labelled macrorestriction fragments, gene probing, two-dimensional PFGE and restriction enzyme site generation. Analysis of the individual macrorestriction patterns of the 17 Asel-, 6 Dral- and 22 Asel/Dral-digested fragments indicated a chromosome size of about 8 Mb. Linking clones for five contiguous Asel fragments were obtained, covering 32% of the chromosome. The linkage of an additional eight Asel fragments was aided by the finding that the rRNA operons of S. erythraea contain an Asel site within the 16S (rrs) gene. Generation of S. erythraea strains that contain additional Dral sites within selected Asel fragments, followed by PFGE analysis and Southern hybridization to determine specific linkages, facilitated the completion of the Asel map. The entire Dral map was constructed by gene probing and cross-hybridizations. PFGE analysis of agarose-embedded DNA prepared in either the presence or absence of proteinase K suggested that the S. erythraea NRRL 2338 chromosome is linear. A total of 15 genes or gene clusters were mapped to specific Asel and Dral fragments, including the erythromycin-biosynthetic gene cluster and the rRNA operons.
Manganous ions suppress photosynthesis gene expression in Rhodobacter sphaeroides
Authors: Horne Irene M. , Pemberton John M. , McEwan Alastair G.
Published: June 2009

The effect of manganous ions [Mn(II)] and ferrous ions [Fe(II)] on expression of photosynthesis genes in Rhodobacter sphaeroides was investigated. The presence of Mn(II) during phototrophic (anaerobic) and chemotrophic (aerobic) growth of R. sphaeroides caused a decrease in the amount of bacteriochlorophyll and carotenoid pigments which were synthesized and this was associated mainly with a decrease in the level of light-harvesting complex II. Mn(II) was shown to cause a decrease in expression of the puc operon, which encodes the polypeptides of light-harvesting complex II. Expression of the puc operon is controlled by the central repressor of photosynthesis gene expression, PpsR. In a ppsR mutant there was no effect of Mn(II) on photosynthesis gene expression. It is concluded that Mn(II) may act as a compressor in the action of PpsR or act via an as yet uncharacterized protein that interacts with PpsR. In contrast to the effects of Mn(II), Fe(II) was required for high levels of photosynthesis gene expression. This requirement for Fe(II) was shown to be related to the regulation of hemA, a gene under the control of the transcriptional regulator, FnrL. Mn(II) did not affect FnrL-dependent gene expression.
The vanadate-tolerant yeast Hansenula polymorpha undergoes cellular reorganization during growth in, and recovery from, the presence of vanadate
Authors: Mannazzu Ilaria , Guerra Emanuela , Strabbioli Rosanna , Pediconi Dario , Fatichenti Fabrizio
Published: June 2009

When present at intracellular concentrations above micromolar, vanadate becomes toxic to most organisms. However, the yeast Hansenula polymorpha is able to grow on vanadate concentrations in the millimolar range, showing at the same time modifications in cellular ultrastructure and polyphosphate metabolism. Here, the development of the ultrastructural changes, and of vacuolar and secretory activities, during exponential growth on vanadate and upon a return to vanadate-free conditions was investigated. External invertase secretion was inhibited by vanadate, as shown by a decrease in external invertase activity, an intracellular accumulation of small vesicles and a cytoplasmic accumulation of internal invertase. An aberrant appearance of the cell wall and defects in cellular surface growth, possibly linked to defects in secretion, were also observed. However, inhibition of the secretory pathway was not complete since the activity of another secreted enzyme, exoglucanase, increased in the presence of vanadate. Growth on vanadate was also accompanied by an enhancement of vacuolar proteolysis, as indicated by an increase in carboxypeptidase Y activity. However, these modifications were all reversible upon return to vanadate-free conditions, with the normalization process being complex and involving new and dramatic ultrastructural changes and activation of an autophagic mechanism. This mechanism is involved in the elimination/resorption of the observed vanadate-induced aberrant cell structures and/or sites involved in vanadate accumulation, a necessary prerequisite for restoration of conventional ultrastructure and metabolic functions.
Glutamine biosynthesis and the utilization of succinate and glutamine by Rhizobium etli and Sinorhizobium meliloti
Authors: Encarnación Sergio , Calderón Jorge , Gelbard Alan S. , Cooper Arthur J. L , Mora Jaime
Published: June 2009

Sinorhizobium meliloti 1021 and Rhizobium etli CE3 turn over nitrogen and carbon from glutamine to ammonium and CO2, respectively. Some of the ammonium released is assimilated back into glutamine, indicating that a glutamine cycle similar to that in Neurospora operates in Rhizobium. In addition, a previously unrecognized metabolic pathway in Rhizobium was discovered - namely, conversion of glutamine-carbon to γ-hydroxybutyric acid and β-hydroxybutyric acid. Additionally, some of the 2-oxoglutarate derived from glutamine catabolism in Rhizobium is converted to succinate in glutamine-containing medium. Both S. meliloti 1021 and R. etli CE3 oxidize succinate preferentially over glutamine when provided with both carbon sources. In contrast to Sinorhizobium meliloti 1021 and Rhizobium etli CE3, an S. meliloti double mutant that lacks both glutamine synthetase (GS) I and II preferentially oxidizes glutamine over succinate when supplied with both substrates. GSII activity is induced in wild-type S. meliloti 1021 and R. etli CE3 grown in succinate-glutamine medium, and this enzyme participates in the cycling of glutamine-carbon and -nitrogen. On the other hand, GSII activity is repressed in both micro-organisms when glutamine is the only carbon source. These findings show that, in medium containing both glutamine and succinate, glutamine synthesis helps drive the utilization of succinate. When glutamine is in excess as an energy-providing substrate its synthesis is restricted, allowing for more effective utilization of glutamine as an energy source.
The tylosin producer, Streptomyces fradiae, contains a second valine dehydrogenase
Authors: Nguyen Lieu Thi , Nguyen Kien Trung , Spízek Jaroslav , Behal Vladislav
Published: June 2009

A second NAD-dependent valine dehydrogenase (VDH) of Streptomyces fradiae was detected and purified to homogeneity by affinity chromatography on Reactive-Blue 2 Sepharose followed by gel filtration and Mono Q fast protein liquid chromatography. The relative molecular masses of the native enzyme and its subunits were determined to be 80000 and 41000, respectively, indicating that the enzyme is a homodimer. The enzyme was the only active VDH in S. fradiae; its activity was significantly induced by L-valine, but was repressed by ammonia. Among branched- and straight-chain amino acids that serve as enzyme substrates, L-2-aminobutyrate and L-valine are preferred. Significant activities were found with deamino-NAD+ and 3-pyridinealdehyde-NAD-. The molecular and catalytic properties of the enzyme distinguish it from the enzyme previously purified, and thus indirectly indicate the existence of two VDHs in S. fradiae.
Involvement of ArgR and PepA in the pairing of ColE1 dimer resolution sites
Authors: Guhathakurta Anjan , Summers David
Published: June 2009

Dimer formation and associated copy number depression is an important cause of multicopy plasmid instability. Natural multicopy plasmids employ site-specific recombination to convert dimers to monomers, thus maximizing the number of independently segregating molecules at cell division. Resolution of dimers of Escherichia coli plasmid ColE1 requires the plasmid cer site and at least four chromosome-encoded proteins: the XerC and XerD recombinases, and accessory factors ArgR and PepA. It has been suggested that ArgR has a role in the initial pairing of recombination sites and we describe here an attempt to detect this process in vivo. Our approach exploits a previous observation that a cer-like site known as the type II hybrid supports inter-molecular recombination and causes extensive multimerization of plasmids. We report that type-II-mediated multimerization can be repressed by a cer site in cis or in trans and propose that this is due to a physical interaction between the sites. If this hypothesis is correct, suppression of multimer formation provides an assay of site pairing. Our results demonstrate that the putative pairing interaction is independent of the topological relationship of the sites and that both PepA and ArgR are involved. Although most recombination-deficient mutant derivatives of ArgR are unable to pair recombination sites, we have found two (ArgR110 and ArgR115*) which retain pairing activity. The validity of the pairing hypothesis is discussed in the light of alternative explanations for our data.
The Bacillus subtilis dnal gene is part of the dnaB operon
Authors: Bruand Claude , Ehrlich S. Dusko
Published: June 2009

The dnal gene of Bacillus subtilis, previously identified through the isolation of the dnal2 mutant, was found to be the second gene of the dnaB operon. The nucleotide substitution in the dnal2 mutant gene was determined.
Heterogeneity among 16S-23S rRNA intergenic spacers of species within the ‘Streptococcus milleri group’
Authors: Whiley R. A. , Duke B. , Hardie J. M. , Hall L. M. C.
Published: June 2009

The 16S-23S rRNA intergenic spacer has been suggested as a suitable region of the bacterial genome from which to derive useful taxonomic information, particularly with regard to identification at the species level. To investigate this approach as an aid to the identification of the three species comprising the ‘Streptococcus milleri group’ (SMG), the spacers of isolates of Streptococcus intermedius, Streptococcus anginosus and Streptococcus constellatus were amplified by PCR and length polymorphisms determined by agarose gel electrophoresis. Phenotypically atypical isolates which had been identified presumptively as belonging to these three species were also included. Spacers from two representatives of each spacer length found within the three SMG species were sequenced. 16S-23S rRNA intergenic spacer length polymorphisms allowed discrimination between S. anginosus (350 bp or 450 bp amplification product) and S. constellatus (380 bp amplification product), species that are difficult to differentiate phenotypically. S. intermedius (330 bp or 450 bp amplification product) and S. anginosus (350 bp or 450 bp amplification product) were not reliably distinguished by this method but are phenotypically distinct. Sequencing data demonstrated that the spacers had a central region of highly variable length flanked by conserved regions which included a single tRNAAla gene. Polymorphism in the length of the 16S-23S spacer determined by PCR provides a rapid and useful adjunct to strain identification for S. anginosus and S. constellatus, which are not readily differentiated phenotypically.
Novel cell-wall teichoic acid from Nocardiopsis albus subsp. albus as a species-specific marker
Authors: Tul'skaya Elena M. , Shashkov Alexander S. , Evtushenko Ludmila I. , Taran Victoriya V. , Naumova Irina B.
Published: June 2009

Cell walls of the three Nocardiopsis albus subsp. albus strains, DSM 43377T, 43378 and 43120 contain structurally identical teichoic acids. The cell wall of each strain has three distinct types of teichoic acids: (1) unsubstituted 3,5-poly(ribitol phosphate), (2) 1,3-poly(glycerol phosphate) partially substituted at C-2 with α-N-acetylglucosamine residues, and (3) 1,5-poly(ribitol phosphate) with each ribitol unit carrying a 2,4-pyruvate ketal group. Types 1 and 3 are reported in prokaryotes for the first time. The structure of the teichoic acids was elucidated by chemical analysis and NMR-spectroscopic methods. Structural identity of the teichoic acids from the three strains belonging to the same species may demonstrate the species-specificity of these polymers.
A heterologous reductase affects the redox balance of recombinant Saccharomyces cerevisiae
Authors: Meinander Nina , Zacchi Guido , Hahn-Hägerdal Bärbel
Published: June 2009

Recombinant Saccharomyces cerevisiae harbouring the xylose reductase (XR) gene XYL1 from Pichia stipitis was grown in anoxic chemostat culture at two different dilution rates. At each dilution rate a transient experiment, encompassing a shift in the sugar content of the medium from glucose to glucose plus xylose was performed. The steady states at the beginning and the end of the transients were compared in terms of specific product fluxes from glucose metabolism. At both dilution rates, the specific glycerol flux decreased and the specific acetate and CO2 fluxes increased. The specific ethanol flux was not affected. At the lower dilution rate, the production of biomass decreased during the transient, but at the higher dilution rate it increased. The changes in product pattern can be explained as being due to the redox perturbation caused by the consumption of reduced cofactors in the XR-catalysed reaction. Regeneration of NAD partly through xylose reduction instead of glycerol production decreased the formation of glycerol. Additionally, xylose reduction activated those pathways which produce reduced cofactors, such as acetate formation and the pentose phosphate pathway, indicated by increased acetate and CO2 production. The dual cofactor specificity of XR, with a preference for NADPH over NADH, was evident from the effects of xylose reduction on product fluxes. Comparison of the xylose reduction rates at low and high glucose flux indicated that the supply of reduced cofactors partly controlled the reaction rate. At the higher dilution rate, control by some other factor such as xylose transport or XR activity increased. Calculation of carbon balances at the steady states showed that all substrate carbon was recovered in biomass or products. Based on the specific product fluxes, calculations of quantitative cofactor balances at the steady states was attempted. However, sensitivity calculations showed that analysis errors in the range of 5% caused substantial errors in the cofactor balance, without affecting the carbon balance.
Phylogenetic analyses of the homologous transmembrane channel-forming proteins of the F0F1-ATPases of bacteria, chloroplasts and mitochondria
Authors: Blair Alan , Ngo Linh , Park James , Paulsen Ian T. , Saier Milton H.
Published: June 2009

Sequences of the three integral membrane subunits (subunits a, b and c) of the F0sector of the proton-translocating F-type (F0F1-) ATPases of bacteria, chloroplasts and mitochondria have been analysed. All homologous-sequenced proteins of these subunits, comprising three distinct families, have been identified by database searches, and the homologous protein sequences have been aligned and analysed for phylogenetic relatedness. The results serve to define the relationships of the members of each of these three families of proteins, to identify regions of relative conservation, and to define relative rates of evolutionary divergence. Of these three subunits, c-subunits exhibited the slowest rate of evolutionary divergence, b-subunits exhibited the most rapid rate of evolutionary divergence, and a-subunits exhibited an intermediate rate of evolutionary divergence. The results allow definition of the relative times of occurrence of specific events during evolutionary history, such as the intragenic duplication event that gave rise to large c-subunits in eukaryotic vacuolar-type ATPases after eukaryotes diverged from archaea, and the extragenic duplication of F-type ATPase b-subunits that occurred in bluegreen bacteria before the advent of chloroplasts. The results generally show that the three F0subunits evolved as a unit from a primordial set of genes without appreciable horizontal transmission of the encoding genetic information although a few possible exceptions were noted.
The inlA gene required for cell invasion is conserved and specific to Listeria monocytogenes
Authors: Poyart Claire , Trieu-Cuot Patrick , Berche Patrick
Published: June 2009

The Gram-positive bacterium Listeria monocytogenes can actively induce its own uptake by epithelial cells and fibroblasts through a surface-exposed 80 kDa protein, internalin (InlA), encoded by inlA. We studied the distribution and the DNA polymorphism of inlA sequences in a wide variety of wild strains of L. monocytogenes as compared to other Listeria species. This was done by PCR-amplifying inlA sequences encoding the fifteen repeats A and the three repeats B of InlA. inlA-repeated sequences were only found in L. monocytogenes. The amplified fragment of inlA encoding the repeats A displayed an AluI DNA polymorphism which arises from point mutations. These results indicate that inlA required for cell invasion is specific to L. monocytogenes and that the intragenic repeats only exhibit a genetic heterogeneity due to point mutations and not to recombinations.
Monoclonal antibody recognition of members of the meningococcal P1.10 variable region family: implications for serological typing and vaccine design
Authors: Suker Janet , Feavers Ian M. , Maiden Martin C. J.
Published: June 2009

Identification of antigenic variants of the PorA protein of Neisseria meningitidis with specific mAbs (serosubtyping) is used in meningococcal strain characterization and the resultant data has been exploited in the design of novel multivalent vaccines against this important pathogen. The reactivity of the P1.10 serosubtyping mAb MN20F4.17 with eight members of the meningococcal P1.10 variable region (VR) family (prototype P1.10 and variants P1.10a-P1.10g), identified by nucleotide sequence analysis of porA genes, was investigated. Analysis of overlapping synthetic octapeptides by ELISA demonstrated that the peptide sequence, QNQRPTL, present only in the prototype P1.10, was sufficient for binding of the mAb. A linear peptide of 14 amino acids, containing the minimum epitope, inhibited binding of mAb MN20F4.17 to whole cells in a competitive ELISA. This binding was weak compared with a tethered peptide or the native protein. In whole-cell ELISA or dot-blot assays using low concentrations of mAb MN20F4.17 only the prototype P1.10 was detected. However, when higher concentrations of antibody were used the prototype P1.10 was detected, together with variants P1.10a, P1.10c and P1.10e by whole-cell ELISA and P1.10a and P1.10c by the immunoblot technique. The variants P1.10b, P1.10d, P1.10f and P1.10g showed no reactivity with mAb under any of the conditions tested. A survey of the porA genes in serogroup B and C strains revealed that the P1.10a variant, rather than the prototype P1.10, was the most common member of the P1.10 VR family in England and Wales. These data illustrate: (i) the problems associated with epidemiological analyses that rely solely on monoclonal antibodies; (ii) the importance of using defined assay conditions for serosubtyping; and (iii) that genetical analyses provide more reliable information than serological data based on murine reagents for the design of candidate vaccines that include PorA.
Global regulation in Erwinia species by Erwinia carotovora rsmA, a homologue of Escherichia coli csrA: repression of secondary metabolites, pathogenicity and hypersensitive reaction
Authors: Mukherjee Asita , Cui Yaya , Liu Yang , Dumenyo C. Korsi , Chatterjee Arun K.
Published: June 2009

Summary: Our previous studies revealed that rsmA of Erwinia carotovora subsp. carotovora strain 71 suppressed the synthesis of the cell density (quorum) sensing signal N-(3-oxohexanoyl)-L-homoserine lactone, the production of extracellular enzymes and tissue macerating ability in soft-rotting Erwinia species and that homologues of this negative regulator gene were present in other Erwinia species. Northern blot data presented here demonstrate that rsmA and rsmA-like genes are also expressed in soft-rotting and non-soft-rotting Erwinia spp. such as E. amylovora, E. carotovora subsp. atroseptica, E. carotovora subsp. betavasculorum, E. carotovora subsp. carotovora, E. chrysanthemi, E. herbicola and E. stewartii. A low-copy plasmid carrying rsmA of E. carotovora subsp. carotovora strain 71 caused suppression of antibiotic production in E. carotovora subsp. betavasculorum, flagellum formation in E. carotovora subsp. carotovora, carotenoid production in E. herbicola and E. stewartii, and indigoidine production in E. chrysanthemi. In E. amylovora, rsmA of E. carotovora subsp. carotovora suppressed the elicitation of the hypersensitive reaction in tobacco leaves and the production of disease symptoms in apple shoots, in addition to repressing motility and extracellular polysaccharide production. We conclude that rsmA homologues function as global regulators of secondary metabolic pathways as well as factors controlling host interaction of Erwinia species.
Intra-Specific Diversity within Pasteurella Trehalosi based on Variation of Capsular Polysaccharide, Lipopolysaccharide and Outer-Membrane Proteinsx
Authors: Davies R. L. , Quirie M.
Published: June 2009

Intra-specific diversity withinPasteurella trehalosiwas investigated by analysis of variation of capsular polysaccharide, and lipopolysaccharide (LPS) and outer-membrane protein (OMP) profiles. Sixty isolates ofP. trehalosifrom diverse geographical locations within the UK, were examined. Capsular polysaccharide serotypes were determined by indirect haemagglutination assay; LPS and OMP profiles were compared by SDS-PAGE analysis. Capsular serotyping identified three isolates of serotype T3, 18 isolates each of serotypes T4, T10 and T15, and three untypable (UT) isolates. Analysis of LPS and OMP profiles identified six smooth LPS types and four OMP types among the 60 isolates. Forty-five (75%) of the isolates belonged to a single OMP type whereas 52 (87%) of the isolates possessed one of three LPS types. Each typing method, by itself, was not very discriminating but when the data from the three methods were combined, the 60 isolates could be separated into 14 distinct subgroups containing from one to 16 isolates as follows: serotype T3, two subgroups; serotype T4, four subgroups; serotype T10, two subgroups; serotype T15, five subgroups; UT isolates, one subgroup. Certain subgroups were associated with only one serotype whereas other subgroups were common to two or more serotypes. The subgroupings were capable of differentiating between isolates of the same serotype from the same and different geographical origins. Based on their LPS and OMP profiles, isolates of serotypes T4 and T15 were more closely related to each other than to isolates of serotype T10; serotype T4 and T15 isolates were also more heterogeneous than those of serotype T10. Certain isolates of serotype T10, recovered from a wide geographical area, were characterized by the possession of a unique capsule/LPS/OMP combination and represented a single clonal group which was responsible for a large proportion (31%) of recent disease outbreaks. Overall, a combination of capsular serotyping, and LPS and OMP typing, was found to be extremely useful for assessing diversity withinP. trehalosiand should be of value for epidemiological and virulence studies.
Genetic relationships among rhizopine-producing Rhizobium strains
Authors: Wexler M. , Gordon D. M. , Murphy P. J.
Published: June 2009

Chromosomal and symbiosis-related genotypes of rhizopine-producing and non-producing isolates of Rhizobium meliloti and Rhizobium leguminosarum were examined by multilocus enzyme electrophoresis and RFLP. The distribution of rhizopine production in both species was found to be independent of host genotype. Conversely, rhizopine production was associated with particular symbiotic plasmid types. This association may explain the observed distribution of rhizopine production in R. leguminosarum and R. meliloti. Rhizopine synthesis (mos) genes showed greater sequence divergence than rhizopine catabolism (moc) genes in both R. meliloti and R. leguminosarum. Furthermore, mos and moc genes were less divergent in R. leguminosarum than R. meliloti, suggesting a more recent evolution in the former species.
Acquisition of iron by the non-siderophore-producing Pseudomonas fragi
Authors: Champomier-Vergès Marie-Christine , Stintzi Alain , Meyer Jean-Marie
Published: June 2009

The iron requirement, siderophore production and iron uptake mechanisms of the type strain Pseudomonas fragi ATCC 4973 and five P. fragi isolates from meat were analysed. The strains exhibited a high sensitivity to iron starvation: their growth was strongly inhibited in medium supplemented with the iron chelator ethylenediamine di(hydroxyphenylacetic acid) or in medium treated with 8-hydroxyquinoline to remove contaminating iron. No siderophores were detectable in the growth supernatants of iron-starved cells. Cross-feeding experiments in iron-depleted medium showed, however, that the bacterial growth could be strongly stimulated by siderophores of foreign origin including desferriferrioxamine B, enterobactin and some pyoverdines. Moreover, all the strains were capable of efficiently using the iron sources present in their natural environment, i.e. transferrin, lactoferrin and haemoglobin. Iron starvation led to the specific production of supplementary outer-membrane proteins of apparent molecular mass ranging from 80 to 88 kDa. Furthermore, growth in the presence of exogenous siderophores resulted, in some strains, in the induction of siderophore-mediated iron uptake systems. For one strain the concomitant synthesis of an iron-regulated, siderophore-inducible outer-membrane protein was observed.
A role for pabAB, a p-aminobenzoate synthase gene of Streptomyces venezuelae ISP5230, in chloramphenicol biosynthesis
Authors: Brown Michael P. , Aidoo Kwamena A. , Vining Leo C.
Published: June 2009

Mutagenesis of Streptomyces venezuelae ISP5230 and selection for p-aminobenzoic acid-dependent growth in the presence of sulfanilamide yielded pab mutants (VS519 and VS620) that continued to produce chloramphenicol (Cm), although with increased medium dependence. Transforming the mutants with pDQ102 or pDQ103, which carried a pab-complementing fragment from S. venezuelae ISP5230 in alternative orientations, restored uniformly high Cm production in VS620, but did not alter the medium dependence of Cm production in VS519. The cloned S. venezuelae DNA fragment was subcloned and trimmed to the minimum size conferring pab complementation. The resulting 2.8 kb BamHI-SacI fragment was sequenced. Codon preference analysis showed one complete ORF encoding a polypeptide of 670 amino acids. Comparison of the deduced amino acid sequence with database proteins indicated that the N- and C-terminal regions resembled PabA and PabB, respectively, of numerous bacteria. The gene product showed overall sequence similarity to the product of a fused pabAB gene associated with secondary metabolism in Streptomyces griseus. Insertion of an apramycin resistance gene into pabAB cloned in a segregationally unstable vector and replacement of the S. venezuelae chromosomal pabAB with the disrupted copy lowered sulfanilamide resistance from 25 to 5 μg ml-1 and blocked Cm production.
The T‐DNA integration pattern in Arabidopsis transformants is highly determined by the transformed target cell
Authors: De Buck Sylvie , Podevin Nancy , Nolf Jonah , Jacobs Anni , Depicker Ann
Published: June 2009

Transgenic loci obtained after Agrobacterium tumefaciens‐mediated transformation can be simple, but fairly often they contain multiple T‐DNA copies integrated into the plant genome. To understand the origin of complex T‐DNA loci, floral‐dip and root transformation experiments were carried out in Arabidopsis thaliana with mixtures of A. tumefaciens strains, each harboring one or two different T‐DNA vectors. Upon floral‐dip transformation, 6–30% of the transformants were co‐transformed by multiple T‐DNAs originating from different bacteria and 20–36% by different T‐DNAs from one strain. However, these co‐transformation frequencies were too low to explain the presence of on average 4–6 T‐DNA copies in these transformants, suggesting that, upon floral‐dip transformation, T‐DNA replication frequently occurs before or during integration after the transfer of single T‐DNA copies. Upon root transformation, the co‐transformation frequencies of T‐DNAs originating from different bacteria were similar or slightly higher (between 10 and 60%) than those obtained after floral‐dip transformation, whereas the co‐transformation frequencies of different T‐DNAs from one strain were comparable (24–31%). Root transformants generally harbor only one to three T‐DNA copies, and thus co‐transformation of different T‐DNAs can explain the T‐DNA copy number in many transformants, but T‐DNA replication is postulated to occur in most multicopy root transformants. In conclusion, the comparable co‐transformation frequencies and differences in complexity of the T‐DNA loci after floral‐dip and root transformations indicate that the T‐DNA copy number is highly determined by the transformation‐competent target cells.
The SARS epidemic in mainland China: bringing together all epidemiological data
Authors: Feng Dan , De Vlas Sake J. , Fang Li‐Qun , Han Xiao‐Na , Zhao Wen‐Juan , Sheng Shen , Yang Hong , Jia Zhong‐Wei , Richardus Jan Hendrik , Cao Wu‐Chun
Published: June 2009

Objective  To document and verify the number of cases of severe acute respiratory syndrome (SARS) during the 2002–2003 epidemic in mainland China.

Method  All existing Chinese SARS data sources were integrated in one final database. This involved removing non‐probable and duplicate cases, adding cases at the final stage of the outbreak, and collecting missing information.

Results  The resulting database contains a total of 5327 probable SARS cases, of whom 343 died, giving a case fatality ratio (CFR) of 6.4%. While the total number of cases happens to be equal to the original official reports, there are 5 cases overall which did not result in death. When compared with Hong Kong Special Administrative Region of China, China Taiwan, and Singapore, the SARS epidemic in mainland China resulted in a considerably lower CFR, involved relatively younger cases and included fewer health care workers.

Conclusions  To optimise future data collection during large‐scale outbreaks of emerging or re‐emerging infectious disease, China must further improve the infectious diseases reporting system, enhance collaboration between all levels of disease control, health departments, hospitals and institutes nationally and globally, and train specialized staff working at county centres of disease control.
Movement disorders associated with complex regional pain syndrome in children
Authors: AGRAWAL SHAKTI K , RITTEY CHRISTOPHER D , HARROWER NEIL A , GODDARD JOHN M , MORDEKAR SANTOSH R
Published: June 2009

The aim of the present study was to review the history, clinical course, treatment, and outcome of movement disorders in children and young people with complex regional pain syndrome (CRPS). Case notes were reviewed retrospectively of children and young people who presented with movement disorders in CRPS to our tertiary paediatric pain service over a period of 13 years. Ten children with CRPS presented with movement disorders (eight females, two males). The age at first presentation with symptoms of CRPS ranged from 8 to 15 years (mean 11y 2mo, median 13y). The most common movement disorder was dystonia (n=8), followed by tremors (n=3) and myoclonus (n=3); two patients had all three movement disorders. The movement disorder affected mainly the lower limb (n=9) with a predilection for the foot (n=7) and was frequently initiated by minor trauma (n=7). Follow‐up ranged from 6 months to 14 years. The outcome was variable, with good prognosis in nearly half of the cases: four children experienced complete resolution of symptoms. Two children showed a slight improvement. Four children showed no improvement. Movement disorders in CRPS are under‐recognized in children. The management has to be multidisciplinary with an expertize in paediatric pain.
Gross motor performance and self‐perceived motor competence in children with emotional, behavioural, and pervasive developmental disorders: a review
Authors: EMCK CLAUDIA , BOSSCHER RUUD , BEEK PETER , DORELEIJERS THEO
Published: June 2009

Aims  Motor performance and self‐perceived motor competence have a great impact on the psychosocial development of children in general. In this review, empirical studies of gross motor performance and self‐perception of motor competence in children with emotional (depression and anxiety), behavioural, and pervasive developmental disorders are scrutinized, with the objective of identifying specific motor characteristics that may be relevant to clinical practice.

Method  A systematic search of studies published between 1997 and 2007 was performed using nine search engines.

Results  Children in all three categories (emotional, behavioural, and pervasive developmental disorders) exhibit poor gross motor performance and problematic self‐perception of motor competence, with certain indications of disorder‐specific characteristics. In particular, children with emotional disorders have balance problems and self‐perceived motor incompetence; children with behavioural disorders show poor ball skills and tend to overestimate their motor performance; children with pervasive developmental disorders demonstrate poor gross motor performance and self‐perceived motor incompetence. As a result, children with developmental and emotional disorders are restricted in participating in games and play, which may lead to inactive lifestyles and further disruption of their psychosocial and physical development.

Interpretation  Motor problems need more, to some extent disorder‐specific, attention in clinical practice than has been provided to date.
Recent advances in arginine metabolism: roles and regulation of the arginases
Authors: Morris Jr Sidney M
Published: June 2009

As arginine can serve as precursor to a wide range of compounds, including nitric oxide, creatine, urea, polyamines, proline, glutamate and agmatine, there is considerable interest in elucidating mechanisms underlying regulation of its metabolism. It is now becoming apparent that the two isoforms of arginase in mammals play key roles in regulation of most aspects of arginine metabolism in health and disease. In particular, work over the past several years has focused on the roles and regulation of the arginases in vascular disease, pulmonary disease, infectious disease, immune cell function and cancer. As most of these topics have been considered in recent review articles, this review will focus more closely on results of recent studies on expression of the arginases in endothelial and vascular smooth muscle cells, post‐translational modulation of arginase activity and applications of arginase inhibitors in vivo.
Single nucleotide polymorphism in the ABCG8 transporter gene is associated with gallbladder cancer susceptibility
Authors: Srivastava Anvesha , Tulsyan Sonam , Pandey Sachchida Nand , Choudhuri Gourdas , Mittal Balraj
Published: June 2009

Background: Gallbladder cancer (GBC) usually arises against the background of gallstone disease, which may be causatively related to supersaturation of cholesterol in bile. An imbalance in cholesterol homeostasis because of oversecretion of cholesterol in the gallbladder promotes gallstone formation. The excretion of cholesterol from the liver is regulated by adenosine triphosphate‐binding cassette transporter ABCG8. A common genetic polymorphism D19H of ABCG8 associated with gallstone disease may be causatively related to the genetic predisposition of GBC.

Aim: We aimed to examine the role of ABCG8 D19H (rs11887534) polymorphism in susceptibility to GBC.

Methodology: This study included 171 confirmed GBC patients and 221 controls. Genotyping for the ABCG8 D19H polymorphism was performed by the polymerase chain reaction‐restriction fragment length polymorphism method.

Results: We observed that in our population the ABCG8 DH genotype frequency was significantly higher in GBC patients [P=0.011; odds ratio (OR)=1.79; 95% confidence interval (CI)=1.1–2.8]. Also, at the allele level, ABCG8H conferred an increased risk for GBC (P=0.023; OR=1.60; 95% CI=1.0–2.4). The risk was more pronounced in GBC patients with gallstones (P=0.027; OR=1.85; 95% CI=1.0–3.1), and in patients with an early onset of the disease (P=0.013; OR=2.55, 95% CI=1.2–5.3). However, there was no modulation of GBC risk because of the ABCG8 polymorphism in a gender‐specific manner.

Conclusion: The results suggest that the DH genotype and the H allele of the ABCG8 D19H polymorphism are associated with GBC susceptibility. The GBC patients with gallstone disease harbouring the ABCG8 variant allele are at a higher risk, while the effect of this polymorphism on GBC patients without gallstones appears to be small.
Clinical Evaluation of a Pre‐Set Ultrafiltration Rate Controller Available for Single Pass and Hemodiafiltration Systems
Authors: Ota Kazuo , Suzuki Toshiaki , Ozaku Yasuo , Era Kazuo , Agishi Tetsuzo , Sugino Nobuhiro , Haraguchi Masato , Mitani Naoyuki , Kumazawa Shunji
Published: June 2009

Introduction of high flux‐type dialyzers, such as the RP‐6, makes it necessary to devise an ultrafiltration rate controller for a single pass system. For this purpose, a new pre‐set ultrafiltration rate controller has been developed and examined experimentally and clinically.

The controller has twin chambers, each of which is divided into two symmetrical parts by a vertically‐placed diaphragm. The diaphragm shifts repeatedly from right to left, aspirating in and driving out fresh or used dialysate alternately. If one removes a certain amount of used dialysate from a branch of the efferent line, negative pressure develops and aspirates an equal amount of water from the dialyzer. Therefore, extra dialysate obtained by a pump precisely reflects ultrafiltration rate. The controller has been used on five patients. The scheduled ultrafiltration rate was easily obtainable. The apparatus is also available for hemodiafiltration. Initial clinical trial has been promising.
Tolerance To High Ultrafiltration Rates During Closed Batch Hemodialysis
Authors: Man Nguyen K. , Pils P. , Giulio D. Di , Zingraff J. , Drueke T. , Jungers P. , Funck‐Brentano Jean‐Louis
Published: June 2009

The tolerance to high levels of ultrafiltration that has been observed when using a RP‐6 dialyzer with polyacrylonitrile membrane and a closed batch dialysate delivery system has led the authors to put patients on a free sodium and fluid intake.

Eight patients were put on such a diet for six months. They have been dialyzed four to five hours, three times per week, on a RP‐6‐Rhodial 75. The mean intersession weight gain was 4.29±0.18 Kg after three days for a mean predialytic body weight of 63.55±2.54 Kg. Mean predialytic blood pressure was 138±4 mmHg for systolic pressure and 82±5 mmHg for diastolic pressure.

Mean ultrafiltrate volume was 4.86±0.36 liters which corresponds to a sodium output of 661.3±49.5 mEq. The potassium removal was 83.47±5.72 mEq. Total plasma protein and hematocrit increased 18.8±3.34% and 19.13±3.22%, respectively, when the pre and post‐dialytic values were compared. No clinical sign of fluid overload (dyspnea, edema, etc.) was noted in these patients. Cardiothoracic index remained in the normal range.

This tolerance is due, possibly, to the high sodium concentration (145 mEq/L) in the dialysate. The free sodium and water diet may contribute to a better rehabilitation.
Haemophilia A (factor VIII deficiency) in a litter of Weimaraners
Authors: Dunning M. D. , Averis G. F. , Pattinson H. , Targett M. , Cade S. , Herrtage M. E.
Published: June 2009

Inherited coagulopathies are reported in a number of dog breeds. However, to date, there is no report of Weimaraners suffering factor VIII deficiency (haemophilia A). We report the discovery of haemophilia A in both males from a single litter of Weimaraners. Haemophilia A in human beings often results from a de novo stochastic mutation. We found no evidence using currently available screening tests of haemophilia A in relatives as far back as three generations making a stochastic mutation possible in this litter.
Comparison of computed tomography and magnetic resonance imaging for the evaluation of canine intranasal neoplasia
Authors: Drees R. , Forrest L. J. , Chappell R.
Published: June 2009

Objectives:Canine intranasal neoplasia is commonly evaluated using computed tomography to indicate the diagnosis, to determine disease extent, to guide histological sampling location and to plan treatment. With the expanding use of magnetic resonance imaging in veterinary medicine, this modality has been recently applied for the same purpose. The aim of this study was to compare the features of canine intranasal neoplasia using computed tomography and magnetic resonance imaging.

Methods:Twenty‐one dogs with confirmed intranasal neoplasia underwent both computed tomography and magnetic resonance imaging. The images were reviewed retrospectively for the bony and soft tissue features of intranasal neoplasia.

Results:Overall computed tomography and magnetic resonance imaging performed very similarly. However, lysis of bones bordering the nasal cavity and mucosal thickening was found on computed tomography images more often than on magnetic resonance images. Small amounts of fluid in the nasal cavity were more often seen on magnetic resonance images. However, fluid in the frontal sinuses was seen equally well with both modalities.

ClinicalSignificance:We conclude that computed tomography is satisfactory for evaluation of canine intranasal neoplasia, and no clinically relevant benefit is gained using magnetic resonance imaging for intranasal neoplasia without extent into the cranial cavity.
Stage‐Specific Education/Counseling Intervention in Women with Elevated Blood Pressure
Authors: Daley Linda K. , Fish Anne F. , Frid David J. , Mitchell G. Lynn
Published: June 2009

Many women with elevated blood pressure who seek exercise opportunities require a flexible program with systematic follow‐up. The study framework included motivational readiness (exercise stage of change) from the Transtheoretical Model and self‐efficacy theory. This pilot study, which used a one‐group repeated measures design, tested the feasibility of a stage‐specific education/counseling intervention aimed at improving exercise outcomes in women with elevated blood pressure. Forty women completed a 2.5‐hour session including prescription for moderate‐vigorous exercise on their own, practice on equipment, maintenance of an exercise diary, and contracting; three follow‐up calls (Weeks 1, 2, 3); a visit (Week 4); and a final call (Week 5). After the intervention, 85% of women moved to or remained in the action or maintenance stages of change, the highest levels of readiness; none relapsed. Exercise self‐efficacy and benefits increased and barriers decreased (P<.05); 70% of participants increased exercise performance. The intervention was feasible. Further testing is warranted using larger samples and including a control group.
Central corneal thickness in children with growth hormone deficiency
Authors: Parentin Fulvio , Pensiero Stefano
Published: June 2009

Acta Ophthalmol. 2010: 88: 692–694

Purpose:  To evaluate central corneal thickness (CCT), intraocular pressure (IOP) and eye refraction in patients with congenital growth hormone (GH) deficiency.

Methods:  Retrospective case series. Forty‐five patients with growth defect treated with recombinant GH and 45 healthy children underwent ophthalmological examination, including CCT measurements, applanation tonometry and cycloplaegic refraction.

Results:  The average CCT in the GH deficiency group was 570.6 μm [standard deviation (SD) 37.4]. In the control group, it was 546.0 (SD 24.9). The average IOP in the GH deficiency group was 18.2 mmHg (SD 3.4). In the control group, it was 14.6 (SD 2.0). The mean refractive error (spherical equivalent) in the GH deficiency group was 0.59 D (SD 1.9). In the control group, it was 0.11 (SD 2.1).

Conclusion:  GH and insulin‐like growth factor 1 are involved in ocular growth by influencing the synthesis of the extracellular matrix of the sclera. Children with congenital GH deficiency or insensitivity have a mean hyperopic defect related to a shorter axial length. A number of studies have demonstrated that CCT in newborns is significantly greater than in adults; a decrease in CCT is closely correlated with an increase in corneal diameter. This finding suggests that the growth of the eye, with possible remodelling and stretching of collagen fibres, may play an important role in the reduction of corneal thickness in the first years of life. Therefore, we conclude that a greater CCT can represent a sign of a delayed growth of the eye in patients with GH deficiency. Finally, our study confirms the influence of corneal thickness on IOP measures, and the prevalence of hyperopia among children with growth defect.
Eye movements in German‐speaking children with and without dyslexia when reading aloud
Authors: Trauzettel‐Klosinski Susanne , Koitzsch A Michaela , Dürrwächter Ute , Sokolov Alexander N , Reinhard Jens , Klosinski Gunter
Published: June 2009

Acta Ophthalmol. 2010: 88: 681–691

Purpose:  The phonological difficulty and orthographic regularity of a language influence reading strategies. Only a few studies have been conducted in readers of German, which has a high grapheme–phoneme correspondence. The aim of this study was to investigate, firstly, the influence of different levels of phonological difficulty of reading material in German on reading in children and, secondly, to compare the reading strategies of German children with findings in English‐speaking readers.

Methods:  Eye movements in 16 German children with dyslexia and 16 age‐matched control children (mean age 9.5 ± 0.35 years) in the third and fourth grades of school were recorded by scanning laser ophthalmoscope while they read aloud two texts of differing levels of difficulty.

Results:  In the dyslexia group, reading speed was slowed, and the number of saccades and regressions was raised markedly, although the percentage of regressions only slightly. The number of eye movements increased in both groups with increasing text difficulty, although much more in the dyslexia group than in the control group, whereas fixation duration was not influenced.

Conclusions:  Phonological difficulty influences reading speed and eye movement pattern: children with dyslexia markedly increase their number of eye movements and analyse the text in smaller units per fixation, but keep fixation duration constant. This strategy reflects their favouring of the indirect, sublexical route of grapheme–phoneme conversion, whereas readers of English‐language texts are more likely to prefer the whole‐word approach, i.e. the direct, lexical route that is associated with orthographic memory.
M-ATTRIBUTES ALGORITHM FOR THE SELECTION OF A COMPANY TO BE AFFECTED BY A PUBLIC OFFERING
Authors: GIL-ALUJA JAIME , GIL-LAFUENTE ANA MARIA , KLIMOVA ANNA
Published: June 2009

Perhaps more than ever in the European Union many groups and associations of companies and institutions are trying, in different ways, to play an active role in the economic scene of the Union.

We verified, on the basis of information obtained, that the studies which precede the decision of a Financial Corporation to initiate the launching of a public offering on a certain economic unit/company or to acquire the shares of a Public Limited Company to take over control, are based on numerical mathematics, adapted mainly to the study of the future hypothetical profitability of the group resulting from the merging process or fusion.

We present a proposal based on combinatorial pretopology that leads to an algorithm capable of solving our objective adequately.