bluuebunny/crossref_metadata_2025_split huggingface dataset:
The global regulator H‐NS binds to two distinct classes of sites within the Tn10 transpososome to promote transposition
Authors: Ward Chris M. , Wardle Simon J. , Singh Randeep K. , Haniford David B. 
Published: May 2007

SummaryThe histone‐like nucleoid structuring protein (H‐NS) is a global transcriptional regulator that influences stress response and virulence pathways in Gram‐negative bacteria. H‐NS also promotes Tn10 transposition by binding directly to the transpososome and inducing a conformational change in the transpososome that favours intermolecular transposition events. H‐NS binds preferentially to curved DNA and can bend non‐curved DNA, it self‐oligomerizes and can interact with other proteins. To determine what functions of H‐NS are important in promoting Tn10 transposition, we have examined the ability of two mutant forms of H‐NS, P116S and 1–64, to act in Tn10 transposition. We provide evidence that the initial interaction of H‐NS with the transpososome is dependent on H‐NS binding to a specific structure in DNA flanking the transposon end. Additional molecules of H‐NS then bind within the transposon end. This latter event appears to be directed by H‐NS binding to the Tn10 transposase protein, and is important in maintaining the transpososome in a conformation that promotes intermolecular transposition. The binding of H‐NS to a transposase protein is a novel function for this important regulatory molecule.
Glycosylphosphatidylinositol (GPI) anchor is required in Aspergillus fumigatus for morphogenesis and virulence
Authors: Li Hong , Zhou Hui , Luo Yuanming , Ouyang Haomiao , Hu Hongyan , Jin Cheng 
Published: May 2007

SummaryIn yeast, glycosylphosphatidylinositol (GPI) is essential for viability and plays an important role in biosynthesis and organization of cell wall. Initiation of the GPI anchor biosynthesis is catalysed by the GPI–N‐acetylglucosaminyltransferase complex (GPI–GnT). The GPI3 (SPT14) gene is thought to encode the catalytic subunit of GPI–GnT complex. In contrast to Saccharomyces cerevisiae, little is known about the GPI biosynthesis in filamentous fungi. In this study, the afpig‐a gene was identified as the homologue of the GPI3/pig‐A gene in Aspergillus fumigatus, an opportunistic fungal pathogen. By replacement of the afpig‐a gene with a pyrG gene, we obtained the null mutants. Although the Δafpig‐a mutant exhibited a significant increased cell lysis instead of temperature‐sensitive or conditional lethal phenotype associated to the GPI3 mutant of yeast, they could survive at temperatures from 30°C to 50°C. The analysis of the mutants showed that a completely blocking of the GPI anchor synthesis in A. fumigatus led to cell wall defect, abnormal hyphal growth, rapid conidial germination and aberrant conidiation. In vivo assays revealed that the mutant exhibited a reduced virulence in immunocompromised mice. The GPI anchor was not essential for viability, but required for the cell wall integrity, morphogenesis and virulence in A. fumigatus.
A dedicated haem lyase is required for the maturation of a novel bacterial cytochrome c with unconventional covalent haem binding
Authors: Hartshorne Robert S. , Kern Melanie , Meyer Björn , Clarke Thomas A. , Karas Michael , Richardson David J. , Simon Jörg 
Published: May 2007

SummaryIn bacterial c‐type cytochromes, the haem cofactor is covalently attached via two cysteine residues organized in a haem c‐binding motif. Here, a novel octa‐haem c protein, MccA, is described that contains only seven conventional haem c‐binding motifs (CXXCH), in addition to several single cysteine residues and a conserved CH signature. Mass spectrometric analysis of purified MccA from Wolinella succinogenes suggests that two of the single cysteine residues are actually part of an unprecedented CX15CH sequence involved in haem c binding. Spectroscopic characterization of MccA identified an unusual high‐potential haem c with a red‐shifted absorption maximum, not unlike that of certain eukaryotic cytochromes c that exceptionally bind haem via only one thioether bridge. A haem lyase gene was found to be specifically required for the maturation of MccA in W. succinogenes. Equivalent haem lyase‐encoding genes belonging to either the bacterial cytochrome c biogenesis system I or II are present in the vicinity of every known mccA gene suggesting a dedicated cytochrome c maturation pathway. The results necessitate reconsideration of computer‐based prediction of putative haem c‐binding motifs in bacterial proteomes.
Temperature‐induced regulation of RpoS by a small RNA in Borrelia burgdorferi
Authors: Lybecker Meghan C. , Samuels D. Scott 
Published: May 2007

SummaryThe alternative sigma factor RpoS (σ38 or σS) plays a central role in the reciprocal regulation of the virulence‐associated major outer surface proteins OspC and OspA in Borrelia burgdorferi, the Lyme disease spirochete. Temperature is one of the key environmental signals controlling RpoS, but the molecular mechanism by which the signal is transduced remains unknown. Herein, we identify and describe a small non‐coding RNA, DsrABb, that regulates the temperature‐induced increase in RpoS. A novel 5′ end of the rpoS mRNA was identified and DsrABb has the potential to extensively base‐pair with the upstream region of this rpoS transcript. We demonstrate that B. burgdorferi strains lacking DsrABb do not upregulate RpoS and OspC in response to an increase in temperature, but do regulate RpoS and OspC in response to changes in pH and cell density. Analyses of the rpoS and ospC steady‐state mRNA levels in the dsrABb mutant indicate that DsrABb regulates RpoS post‐transcriptionally. The 5′ and 3′ ends of DsrABb were mapped, demonstrating that at least four species exist with sizes ranging from 213 to 352 nucleotides. We hypothesize that DsrABb binds to the upstream region of the rpoS mRNA and stimulates translation by releasing the Shine‐Dalgarno sequence and start site from a stable secondary structure. Therefore, we postulate that DsrABb is a molecular thermometer regulating RpoS in Borrelia burgdorferi.
Transmembrane transport of peptidoglycan precursors across model and bacterial membranes
Authors: Van Dam Vincent , Sijbrandi Robert , Kol Matthijs , Swiezewska Ewa , De Kruijff Ben , Breukink Eefjan 
Published: May 2007

SummaryTranslocation of the peptidoglycan precursor Lipid II across the cytoplasmic membrane is a key step in bacterial cell wall synthesis, but hardly understood. Using NBD‐labelled Lipid II, we showed by fluorescence and TLC assays that Lipid II transport does not occur spontaneously and is not induced by the presence of single spanning helical transmembrane peptides that facilitate transbilayer movement of membrane phospholipids. MurG catalysed synthesis of Lipid II from Lipid I in lipid vesicles also did not result in membrane translocation of Lipid II. These findings demonstrate that a specialized protein machinery is needed for transmembrane movement of Lipid II. In line with this, we could demonstrate Lipid II translocation in isolated Escherichia coli inner membrane vesicles and this transport could be uncoupled from the synthesis of Lipid II at low temperatures. The transport process appeared to be independent from an energy source (ATP or proton motive force). Additionally, our studies indicate that translocation of Lipid II is coupled to transglycosylation activity on the periplasmic side of the inner membrane.
CCD BVI photometry and Coravel observations of stars in the open cluster NGC 2489
Authors: Piatti Andrés E. , Clariá Juan J. , Mermilliod Jean-Claude , Parisi María C. , Ahumada Andrea V. 
Published: May 2007

Abstract
We present CCD BVI photometry for the southern open cluster NGC 2489 and its surrounding field. The sample consists of 2182 stars measured in an area of 13.6 × 13.6 arcmin2, extending down to V∼ 21.5. These data are supplemented with CORAVEL radial-velocity observations for seven red giant candidates. A cluster angular radius of 6.7 ± 0.6 arcmin, equivalent to 3.5 ± 0.3 pc, is estimated from star counts carried out inside and outside the cluster region. The comparison of the cluster colour–magnitude diagrams with isochrones of the Padova group yields E(B−V) = 0.30 ± 0.05, E(V−I) = 0.40 ± 0.05 and V−MV= 12.20 ± 0.25 for log t= 8.70 (t= 500+130−100 Myr) and Z= 0.019. NGC 2489 is then located at 1.8 ± 0.3 kpc from the Sun and 25 pc below the Galactic plane. The analysis of the kinematical data allowed us to confirm cluster membership for six red giants, one of them being a spectroscopic binary. A mean radial velocity of 38.13 ± 0.33 km s−1 was derived for the cluster red giants. The properties of a sample of open clusters aligned along the line of sight of NGC 2489 are examined.
Intercellular communication in plants: evidence for two rapidly transmitted systemic signals generated in response to electromagnetic field stimulation in tomato
Authors: BEAUBOIS ÉLISABETH , GIRARD SEBASTIEN , LALLECHERE SEBASTIEN , DAVIES ERIC , PALADIAN FRANÇOISE , BONNET PIERRE , LEDOIGT GERARD , VIAN ALAIN 
Published: May 2007

ABSTRACTExposing all of a wild‐type tomato plant to electromagnetic radiation evoked rapid and substantial accumulation of basic leucine‐zipper transcription factor (bZIP) mRNA in the terminal leaf (#4) with kinetics very similar to that seen in response to wounding, while in the abscisic acid (ABA) mutant (Sitiens), the response was more rapid, but transient. Submitting just the oldest leaf (#1) of a wild‐type plant to irradiation evoked bZIP mRNA accumulation both locally in the exposed leaf and systemically in the unexposed (distant) leaf #4, although systemic accumulation was delayed somewhat. Accumulation of Pin2 mRNA was less than bZIP in both the exposed and distant leaves in wild type, but there was no delay in the systemic response. In Sitiens, bZIP mRNA accumulation was far less than in wild type in both local and distant leaves, while Pin2 mRNA accumulation was stronger in the exposed leaf, but totally prevented in the systemic leaf. In the jasmonic acid (JA) mutant (JL‐5) and in wild‐type plants treated with the ABA biosynthesis inhibitor, naproxen, responses were similar to those in the ABA mutant, while treatment of the exposed leaf with calcium antagonists totally abolished both local and systemic increases in bZIP transcript accumulation.
Compatible solutes reduce ROS‐induced potassium efflux in Arabidopsis roots
Authors: CUIN TRACEY ANN , SHABALA SERGEY 
Published: May 2007

ABSTRACTReactive oxygen species (ROS) are known to be primarily responsible for the impairment of cellular function under numerous abiotic and biotic stress conditions. In this paper, using non‐invasive microelectrode ion flux measuring (MIFE) system, we show that the application of a hydroxyl radical (OH•)‐generating Cu2+/ascorbate (Cu/a) mixture to Arabidopsis roots results in a massive, dose‐dependent efflux of K+ from epidermal cells in the elongation zone. Pharmacological experiments suggest that both outward‐rectifying K+ channels and non‐selective cation channels (NSCCs) mediate such effluxes. Low (5 mM) concentrations of compatible solutes (glycine betaine, proline, mannitol, trehalose or myo‐inositol) significantly reduces OH•‐induced K+ efflux, similar to our previous reports for NaCl‐induced K+ efflux. Importantly, a significant reduction in K+ efflux was found using osmolytes with no reported free radical scavenging activity, as well as those for which a role in free radical scavenging has been demonstrated. This indicates that compatible solutes must play other (regulatory) roles, in addition to free radical scavenging, in mitigating the damaging effects of oxidative stress.
Homogalacturonan synthesis in Arabidopsis thaliana requires a Golgi‐localized protein with a putative methyltransferase domain
Authors: Mouille Grégory , Ralet Marie‐Christine , Cavelier Céline , Eland Cathlene , Effroy Delphine , Hématy Kian , McCartney Lesley , Truong Hoai Nam , Gaudon Virginie , Thibault Jean‐François , Marchant Alan , Höfte Herman 
Published: May 2007

SummaryPectins are a family of complex cell‐wall polysaccharides, the biosynthesis of which remains poorly understood. We identified dwarf mutants with reduced cell adhesion at a novel locus, QUASIMODO2 (QUA2). qua2‐1 showed a 50% reduction in homogalacturonan (HG) content compared with the wild type, without affecting other cell‐wall polysaccharides. The remaining HG in qua2‐1 showed an unaltered degree of methylesterification. Positional cloning and GFP fusions showed that QUA2, consistent with a role in HG synthesis, encodes a Golgi‐localized protein. In contrast to QUA1, another Golgi‐localized protein required for HG‐synthesis, QUA2 does not show sequence similarity to glycosyltransferases, but instead contains a putative methyltransferase (MT) domain. The Arabidopsis genome encodes 29 QUA2‐related proteins. Interestingly, the transcript profiles of QUA1 and QUA2 are correlated and other pairs of QUA1 and QUA2 homologues with correlated transcript profiles can be identified. Together, the results lead to the hypothesis that QUA2 is a pectin MT, and that polymerization and methylation of homogalacturonan are interdependent reactions.
Identification of three novel alleles of HLA‐DRB1 and HLA‐A in the Brazilian population†
Authors: Abdeen H. , McErlean C. , Moraes M. E. , Torres M. , Campiotto S. , Galvão S. , Gouvea C. , Middleton D. 
Published: May 2007

AbstractTwo human leukocyte antigen (HLA)‐DRB1 (HLA‐DRB1*1376 and ‐DRB1*1465) and one HLA‐A (HLA‐A*2471) novel alleles have been identified in individuals from the Brazilian Bone Marrow Donor Registry. DNA sequencing of exon 2 for HLA‐DRB1 alleles showed two and five nucleotide substitutions in ‐DRB1*1376 and ‐DRB1*1465, compared with closely related alleles, respectively. These substitutions result in a change of amino acid residues in HLA‐DRB1*1376 at position 74 (Arg → Glu) and in ‐DRB*1465 at positions 47 (Tyr → Phe), 57 (Asp → Ser) and 74 (Glu → Ala). On the other hand, sequence analysis of exons 2 and 3 for HLA‐A*2471 showed a single substitution, leading to a single amino acid change at position 151 (His → Arg). These three novel alleles may have originated from other HLA alleles by gene conversion. However, it is also possible that HLA‐A*2471 has evolved from one of the alleles of the HLA‐A*2402 group through a point mutation.
Increase in recently acquired syphilis infections in English, Welsh and Northern Irish blood donors
Authors: Brant L. J. , Bukasa A. , Davison K. L. , Newham J. , Barbara J. A. 
Published: May 2007

Background and Objectives  Syphilis can be transmitted by blood. We describe syphilis infections detected in blood donors and investigate the epidemiology of syphilis in English, Welsh and Northern Irish blood donors.Materials and Methods  This article analyses routine surveillance data regarding syphilis infections in blood donors from England, Wales and Northern Ireland between 1998 and 2004. Infections are classified as recently acquired or past syphilis and donor characteristics and trends examined.Results  A total of 518 syphilis‐infected donors were identified; 40 had recently acquired infection and 407 had past syphilis (71 were unclassified). Thirteen times more recently acquired syphilis infections were identified among people who donated between 2002 and 2004 compared to 1998 to 2001. Young, white and regular donors were most likely to have recently acquired syphilis infections. Heterosexual sex was the main risk exposure identified overall; in contrast, the greatest proportion of recently acquired infections were in men who have sex with men.Conclusion  The increase in recently acquired syphilis, although low, indicates that risky sexual behaviours are increasing in the blood donor population, with implications for the microbiological safety of blood. Continued vigilance is required by blood services as the risk of syphilis increases in the general population.
Inheritance and gene tagging of male fertility restoration of cytoplasmic‐nuclear male‐sterile line NJCMS1A in soybean
Authors: Yang S. P. , Duan M. P. , Meng Q. C. , Qiu J. , Fan J. M. , Zhao T. J. , Yu D. Y. , Gai J. Y. 
Published: May 2007

AbstractThe F1, F2 and F2:3 of the NJCMS1A × ‘Zhongdou 5’ cross were used to analyse the inheritance of the male fertility restoration of the cytoplasmic‐nuclear male‐sterile line NJCMS1A in soybean. The results of genetic analysis showed two pairs of dominant genes conferring the male fertility restoration of NJCMS1A, which further confirmed previous results. The F2 population from the NJCMS1A × ‘Zhongdou 5’ cross was used for tagging the restorer genes for NJCMS1A with 664 pairs of simple sequence repeat primers selected randomly from the genetic linkage map of soybean published by Cregan et al. (1999). Satt626 on linkage group M and Satt300 on linkage group A1 of the integrated linkage map by Song et al. (2004) were found to link to the two restorer genes of NJCMS1A. The maximum‐likelihood estimates of the genetic distance between the two markers, Satt626 and Satt300, and the two restorer genes of ‘Zhongdou 5’ were 9.75 and 11.18 cM, respectively.
Diagnostic accuracy of shoulder ultrasound performed by a single operator
Authors: Cullen DM , Breidahl WH , Janes GC 
Published: May 2007

SummaryBoth diagnostic ultrasound and magnetic resonance imaging (MRI) are used for investigation of the presence and severity of rotator cuff lesions. There is no consensus as to which is the more accurate and cost‐effective study. We sought to examine the sensitivity of ultrasound, when used by one experienced radiologist with modern equipment. We compared the ultrasound and surgical results obtained from 68 patients. Ultrasound showed a sensitivity of 89% and specificity of 100% (Positive Predictive Value 100%) for full‐thickness tears, and a sensitivity of 79% and specificity of 94% (Positive Predictive Value 87%) for partial‐thickness tears. We found that shoulder ultrasound, in the hands of an experienced radiologist with the use of modern high‐resolution equipment, is highly sensitive in differentiating complete tears and partial‐thickness tears. Our results are similar to the best published results for MRI and given that ultrasound is significantly cheaper and more available, ultrasound by an experienced radiologist should be considered as a primary diagnostic tool for imaging the rotator cuff.
SUBCELLULAR DISTRIBUTION OF DOPAMINE‐β‐HYDROXYLASE AND INHIBITORS IN THE HIPPOCAMPUS AND CAUDATE NUCLEUS IN SHEEP BRAIN
Authors: Lander J. , Austin L. 
Published: May 2007

Abstract—The enzyme dopamine‐β‐hydroxylase (EC 1.14.17.1) which converts dopamine to noradrenaline was found to be present in substantial amounts in sheep brain hypothalamus and caudate nucleus and was located to the synaptic vesicle fractions in these two brain regions by subcellular fractionation. This dopamine‐β‐hydroxylase was associated with paniculate matter in these two brain regions since it was resistant to solubilization with butan‐1‐ol and 0.1% Triton X‐100. As highly significant levels of dopamine‐β‐hydroxylase were present in the caudate nucleus, factors other than a simple lack of this enzyme must operate to maintain the low levels of noradrenaline and high levels of dopamine in the caudate nucleus. Purified adrenal dopamine‐β‐hydroxylase was substantially inhibited by two factors prepared from sheep brain hypothalamus and caudate nucleus. These were found to be cupric ions and a sulphydryl inhibitor. High levels of the sulphydryl inhibitor of dopamine‐β‐hydroxylase were found in synaptosomal fractions from sheep brain hypothalamus and caudate nucleus and the levels were comparable in both regions. Upon subfractionation of a synaptosome‐containing fraction from the hypothalamus, the inhibitor was located predominantly in the soluble fraction, although there were significant levels in the synaptic vesicle fraction. Therefore, the sulphydryl inhibitor must be considered as a possible regulator of dopamine‐β‐hydroxylase activity.Free cupric ion concentrations as low as 2·5 μM were found to inhibit purified adrenal dopamine‐β‐hydroxylase in vitro and the concentration of copper in the soluble tissue component of hypothalamus and caudate nucleus was well above this minimal copper concentration. The percentage content of soluble copper in the caudate nucleus was significantly higher than in the hypothalamus. The importance of the soluble to particulate‐bound ratio of copper in brain was shown in studies of the developing rat brain. A rapid increase in the level of copper in brain was found in the first 4 weeks but the level was constant by 2 months of age. The percentage of soluble copper, however, was maximal soon after birth and had declined to a constant figure by 2 months of age. A scheme for the regulation of dopamine‐β‐hydroxylase activity involving these factors is proposed.
Lack of association between NPHS2 gene polymorphisms and sporadic IgA nephropathy
Authors: MAO JIANHUA , DU LIZHONG , GU WEIZHONG , DAI YUWEN , LIU AIMIN , XIA YONGHUI , ZHANG YANG 
Published: May 2007

SUMMARY:Aim:  IgA nephropathy (IgAN) is the most common primary form of glomerulonephritis worldwide. In the present study, the genetic structure of the NPHS2 gene was studied to verify if podocin plays a role in the pathogenesis of IgAN.Methods:  Clinical characteristics and DNA samples were collected from 26 Chinese children with sporadic IgAN. A direct sequencing was performed after polymerase chain reaction amplification to all the eight exons of the NPHS2 gene.Results:  Three synonymous variants as known polymorphisms (954T→C homozygous, 1038A→G heterozygous and homozygous) were found in 3, 4 and 1 patients, respectively. There was no significant difference in the genotypic and allelic frequencies of 954T > C and 1038A > G polymorphisms between the patients and normal controls.Conclusion:  No significant difference in the genotypic and allelic frequencies of the identified 954T > C and 1038A > G polymorphisms between the patients and normal controls was found.
Vitamin D receptor gene polymorphisms are associated with increased risk and progression of renal cell carcinoma in a Japanese population
Authors: Obara Wataru , Suzuki Yasushi , Kato Karen , Tanji Susumu , Konda Ryuichiro , Fujioka Tomoaki 
Published: May 2007

Aim:  Biological and epidemiologic data suggest that 1 alpha, 25 dihydroxyvitamin D3 (1,25(OH)2D3) levels may influence development of renal cell carcinoma. The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of 1,25(OH)2D3 and additionally interacts with other cell signaling pathways that influence cancer progression. VDR gene polymorphisms may play an important role in risk of incidence for various malignant tumors. This study investigated whether VDR gene polymorphisms were associated with increased risk and prognosis of renal cell carcinoma (RCC) in a Japanese population.Methods:  To analyze risk of RCC depending on VDR polymorphism, a case–control association study was performed. The VDR gene polymorphisms at three locations, BsmI, ApaI and TaqI, were genotyped in 135 RCC patients and 150 controls in a Japanese population. Logistic regression models were used to assess the genetic effects on prognosis.Results:  Significant differences in the ApaI genotype were observed between RCC patients and controls (χ2 = 6.90, P = 0.032). No statistical significant difference was found in the BsmI and TaqI polymorphisms. The frequency of the AA genotype in the ApaI polymorphism was significantly higher in the RCC patients than in the controls (odds ratio, 2.59; 95% confidence intervals, 1.21–5.55; P = 0.012). Multivariate regression analysis showed that the AA genotype was an independent prognostic factor for cause‐specific survival (relative risk 3.3; P = 0.038).Conclusion:  The AA genotype at the ApaI site of the VDR gene may be a risk of incidence and poor prognosis factor for RCC in the Japanese population. Additional studies with a large sample size and investigation of the functional significance of the ApaI polymorphism in RCC cells are warranted.