bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overexpression of the Multidrug Efflux Pumps MexCD-OprJ and MexEF-OprN Is Associated with a Reduction of Type III Secretion in
Pseudomonas aeruginosa
Authors: Linares Juan F. , López Juan A. , Camafeita Emilio , Albar Juan P. , Rojo Fernando , Martínez Jose L. 
Published: February 2005

ABSTRACT

The
Pseudomonas aeruginosa
genome contains several different multidrug resistance (MDR) efflux pumps. Overproduction of these pumps reduces susceptibility to a variety of antibiotics. Some recently published works have analyzed the effect of the overproduction of MDR efflux pumps on bacterial virulence. Here we have studied the effect of overproduction of the efflux pumps MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY on type III secretion (T3S) in
P. aeruginosa
. The type III secretion system (T3SS) is used by
P. aeruginosa
to deliver toxins directly into the cytoplasm of the host cell. Our data indicate that overexpression of either MexCD-OprJ or MexEF-OprN is associated with the impairment of T3S in
P. aeruginosa
. No effect on overexpression of either MexAB-OprM or MexXY was detected. The observed defect in T3S was due to a lack of expression of genes belonging to the T3SS regulon. Transcription of this regulon is activated by ExsA in response to environmental signals. Overexpression of this transcriptional regulator complemented the defect in T3S observed in the MexCD-OprJ- and MexEF-OprN-overproducing strains. Taken together, these results suggest that overproduction of either MexCD-OprJ or MexEF-OprN is associated with a reduction in the transcription of the T3SS regulon due to the lack of expression of the
exsA
gene, encoding the master regulator of the system. The relevance of potential metabolic and quorum-sensing imbalances due to overexpression of MDR pumps associated with this phenotype is also discussed.
Nonessential Genes of Phage φYeO3-12 Include Genes Involved in Adaptation to Growth onYersinia enterocoliticaSerotype O:3
Authors: Kiljunen Saija , Vilen Heikki , Pajunen Maria , Savilahti Harri , Skurnik Mikael 
Published: February 2005

ABSTRACTBacteriophage φYeO3-12 is a T7/T3-related lytic phage that naturally infectsYersinia enterocoliticaserotype O:3 strains by using the lipopolysaccharide O polysaccharide (O antigen) as its receptor. The phage genome is a 39,600-bp-long linear, double-stranded DNA molecule that contains 58 genes. The roles of many of the genes are currently unknown. To identify nonessential genes, the isolated phage DNA was subjected to MuA transposase-catalyzed in vitro transposon insertion mutagenesis with alacZ′ gene-containing reporter transposon. Following electroporation intoEscherichia coliDH10B and subsequent infection ofE. coliJM109/pAY100, a strain that expresses theY. enterocoliticaO:3 O antigen on its surface, mutant phage clones were identified by their β-galactosidase activity, manifested as a blue color on indicator plates. Transposon insertions were mapped in a total of 11 genes located in the early and middle regions of the phage genome. All of the mutants had efficiencies of plating (EOPs) and fitnesses identical to those of the wild-type phage when grown onE. coliJM109/pAY100. However, certain mutants exhibited altered phenotypes when grown onY. enterocoliticaO:3. Transposon insertions in genes0.3to0.7decreased the EOP onY. enterocoliticaO:3, while the corresponding deletions did not, suggesting that the low EOP was not caused by inactivation of the genes per se. Instead, it was shown that in these mutants the low EOP was due to the delayed expression of gene1, coding for RNA polymerase. On the other hand, inactivation of gene1.3or3.5by either transposon insertion or deletion decreased phage fitness when grown onY. enterocolitica. These results indicate that φYeO3-12 has adapted to utilizeY. enterocoliticaas its host and that these adaptations include the products of genes1.3and3.5, DNA ligase and lysozyme, respectively.
New Pathway for Long-Chain
n
-Alkane Synthesis via 1-Alcohol in
Vibrio furnissii
M1
Authors: Park Myong-Ok 
Published: February 2005

ABSTRACT

Alkane biosynthesis in the bacterium
Vibrio furnissii
M1 involves the synthesis of long-chain alkanes via 1-alcohol. Evidence for this novel pathway are the following. (i) Both even- and odd-carbon-number
n
-alkanes were produced from glucose, while only even-carbon-number fatty acids were produced in
V. furnissii
M1. This result cannot be explained by the decarbonylation pathway. (ii) Pentadecane and hexadecane were produced from 1-hexadecanoic acid by membrane fractions of
V. furnissii
M1, and radioisotope precursor-tracer experiments, in which 1-[1-
14
C]hexadecanoic acid was fed, identified the corresponding alcohol, aldehyde, and alkane derivatives. Since all metabolites maintained the radioisotope label at 1-C, they were produced by a pathway in which the carbon structure was retained, i.e., a reduction pathway. (iii)
n
-Hexadecane was produced when 1-hexadecanol was fed to membrane preparations.
Role of the
Escherichia coli glgX
Gene in Glycogen Metabolism
Authors: Dauvillée David , Kinderf Isabelle S. , Li Zhongyi , Kosar-Hashemi Behjat , Samuel Michael S. , Rampling Lynette , Ball Steven , Morell Matthew K. 
Published: February 2005

ABSTRACT

A role for the
Escherichia coli glgX
gene in bacterial glycogen synthesis and/or degradation has been inferred from the sequence homology between the
glgX
gene and the genes encoding isoamylase-type debranching enzymes; however, experimental evidence or definition of the role of the gene has been lacking. Construction of
E. coli
strains with defined deletions in the
glgX
gene is reported here. The results show that the GlgX gene encodes an isoamylase-type debranching enzyme with high specificity for hydrolysis of chains consisting of three or four glucose residues. This specificity ensures that GlgX does not generate an extensive futile cycle during glycogen synthesis in which chains with more than four glucose residues are transferred by the branching enzyme. Disruption of
glgX
leads to overproduction of glycogen containing short external chains. These results suggest that the GlgX protein is predominantly involved in glycogen catabolism by selectively debranching the polysaccharide outer chains that were previously recessed by glycogen phosphorylase.
The BvgAS Signal Transduction System Regulates Biofilm Development inBordetella
Authors: Mishra Meenu , Parise Gina , Jackson Kara D. , Wozniak Daniel J. , Deora Rajendar 
Published: February 2005

ABSTRACTThe majority ofBordetellasp. virulence determinants are regulated by the BvgAS signal transduction system. BvgAS mediates the control of multiple phenotypic phases and a spectrum of gene expression profiles specific to each phase in response to incremental changes in the concentrations of environmental signals. Studies highlighting the critical role of this signaling circuitry in theBordetellainfectious cycle have focused on planktonically growing bacterial cells. It is becoming increasingly clear that the major mode of bacterial existence in the environment and within the body is a surface-attached state known as a biofilm. Biofilms are defined as consortia of sessile microorganisms that are embedded in a matrix. During routine growth ofBordetellaunder agitating conditions, we noticed the formation of a bacterial ring at the air-liquid interface of the culture tubes. We show here that this surface adherence property reflects the ability of these organisms to form biofilms. Our data demonstrate that the BvgAS locus regulates biofilm development inBordetella. The results reported in this study suggest that the Bvg-mediated control in biofilm development is exerted at later time points after the initial attachment of bacteria to the different surfaces. Additionally, we show that these biofilms are highly tolerant of a number of antimicrobials, including the ones that are currently recommended for treatment of veterinary and human infections caused byBordetellaspp. Finally, we discuss the significance of the biofilm lifestyle mode as a potential contributor to persistent infections.
Host Gene Expression Changes and DNA Amplification during Temperate Phage Induction
Authors: Frye Jonathan G. , Porwollik Steffen , Blackmer Felisa , Cheng Pui , McClelland Michael 
Published: February 2005

ABSTRACT

Salmonella enterica
serovar Typhimurium LT2 harbors four temperate prophages. The lytic cycle of these phages was induced with hydrogen peroxide or mitomycin C. Microarray analysis was used to monitor the increase in phage genome copy number and the changes in RNA expression. Phage gene transcription was classified temporally, and host genes that responded to hydrogen peroxide, mitomycin C, or phage induction were also identified. A region of the serovar Typhimurium LT2 host genome encompassing hundreds of genes, flanking the Fels-1 lambdoid prophage, was amplified manyfold during lytic induction, presumably due to Fels-1 runoff replication prior to excision, a phenomenon termed escape replication. An excisionase (
xis
) mutant of Fels-1 also induced escape replication but did not get packaged. Gifsy-1, a lambdoid prophage that does not normally produce escape replication, did so after deletion of either its integrase or excisionase genes. Escape replication is probably widespread; large regions of host genome amplification were also observed after phage induction in serovar Typhimurium strains SL1344 and 14028s at the suspected integration site of prophage genomes.
Potent Anti-R5 Human Immunodeficiency Virus Type 1 Effects of a CCR5 Antagonist, AK602/ONO4128/GW873140, in a Novel Human Peripheral Blood Mononuclear Cell Nonobese Diabetic-SCID, Interleukin-2 Receptor γ-Chain-Knocked-Out AIDS Mouse Model
Authors: Nakata Hirotomo , Maeda Kenji , Miyakawa Toshikazu , Shibayama Shiro , Matsuo Masayoshi , Takaoka Yoshikazu , Ito Mamoru , Koyanagi Yoshio , Mitsuya Hiroaki 
Published: January 2005

ABSTRACT

We established human peripheral blood mononuclear cell (PBMC)-transplanted R5 human immunodeficiency virus type 1 isolate JR-FL (HIV-1
JR-FL
)-infected, nonobese diabetic-SCID, interleukin 2 receptor γ-chain-knocked-out (NOG) mice, in which massive and systemic HIV-1 infection occurred. The susceptibility of the implanted PBMC to the infectivity and cytopathic effect of R5 HIV-1 appeared to stem from hyperactivation of the PBMC, which rapidly proliferated and expressed high levels of CCR5. When a novel spirodiketopiperazine-containing CCR5 inhibitor, AK602/ONO4128/GW873140 (molecular weight, 614), was administered to the NOG mice 1 day after R5 HIV-1 inoculation, the replication and cytopathic effects of R5 HIV-1 were significantly suppressed. In saline-treated mice (
n
= 7), the mean human CD4
+
/CD8
+
cell ratio was 0.1 on day 16 after inoculation, while levels in mice (
n
= 8) administered AK602 had a mean value of 0.92, comparable to levels in uninfected mice (
n
= 7). The mean number of HIV-RNA copies in plasma in saline-treated mice were ∼10
6
/ml on day 16, while levels in AK602-treated mice were 1.27 × 10
3
/ml (
P
= 0.001). AK602 also significantly suppressed the number of proviral DNA copies and serum p24 levels (
P
= 0.001). These data suggest that the present NOG mouse system should serve as a small-animal AIDS model and warrant that AK602 be further developed as a potential therapeutic for HIV-1 infection.
Wiskott-Aldrich Syndrome Protein Is Needed for Vaccinia Virus Pathogenesis
Authors: Guerra Susana , Aracil Miguel , Conde Raquel , Bernad Antonio , Esteban Mariano 
Published: January 2005

ABSTRACTSmallpox, caused by variola virus, was a devastating disease in humans, but how the virus evolved a strategy to spread to tissue remains unknown. Through the use of microarrays, we identified the gene encoding the Wiskott-Aldrich syndrome protein (WASP), one of the five known WASP family members, which has been induced in the course of infection of human cells with different strains of vaccinia virus (VV) (S. Guerra, L. A. López-Fernández, A. Pascual-Montano, M. Muñoz, K. Harshman, and M. Esteban, J. Virol. 77:6493-6506, 2003; S. Guerra, L. A. López-Fernández, R. Conde, A. Pascual-Montano, K. Harshman, and M. Esteban, J. Virol. 78:5820-5834, 2004). In a mouse model, we evaluated the role of WASP in infection with VV, a close relative of variola virus. WASP−/−(KO) mice infected intranasally and intraperitoneally with VV showed reduced weight loss and mortality compared to wild-type (WT) mice. WASP expression correlated with VV replication in the ovaries but not in the liver or spleen. WT mouse macrophages express WASP but not N-WASP; after VV infection, WASP levels increase threefold. KO macrophages lack N-WASP expression and, when VV infected, are incapable of inducing actin tails and producing extracellular virus. These functions were rescued in KO macrophages after ectopic WASP expression. Overall, our findings demonstrate that WASP has a role in orthopoxvirus infections. Use of WASP proteins for virus spread via the actin tail provides a selective advantage for VV, and probably variola virus, dissemination to distant tissues.
Human Cytomegalovirus Infection of Endothelial Cells Triggers Platelet Adhesion and Aggregation
Authors: Rahbar Afsar , Söderberg-Nauclér Cecilia 
Published: January 2005

ABSTRACT

Human cytomegalovirus (HCMV) is an opportunistic pathogen that has been implicated in the pathogenesis of vascular diseases. HCMV infection of endothelial cells may lead to vascular damage in vitro, and acute-phase HCMV infection has been associated with thrombosis. We hypothesized that viral infection of endothelial cells activates coagulation cascades and contributes to thrombus formation and acute vascular catastrophes in patients with atherosclerotic disease. To assess the effects of HCMV on thrombogenesis, we examined the adhesion and aggregation of blood platelets to uninfected and HCMV-infected endothelial cells. At 7 days after infection, platelet adherence and aggregation were greater in infected than in uninfected cultures (2,000 platelets/100 cells and 225 ± 15 [mean ± standard error of the mean] aggregates/five microscopic fields versus 100 platelets/100 cells and no aggregates). von Willebrand factor (vWF), ICAM-1, and VCAM-1 but not collagen IV, E-selectin, P-selectin, CD13, and CD31 were expressed at higher levels on infected cells than on uninfected cells. Platelet aggregation was inhibited by blocking of platelet GPIb (with blocking antibodies) or GPIIb/IIIa (with ReoPro) or by blocking of vWF (with polyclonal antibodies to vWF). Furthermore, blocking of vWF, platelet GPIb, and ICAM-1 but not of the endothelial cell marker CD13, α
5
β
3
-integrin, or HCMV glycoprotein B reduced platelet adherence to infected cells by 75% ± 5%, 74% ± 5%, or 18% ± 5%, respectively. The increased thrombogenicity was dependent on active virus replication and could be inhibited by foscarnet and ganciclovir; these results suggest that a late viral gene may be mediating this phenomenon, which may contribute to vascular catastrophes in patients with atherosclerotic disease.
The Murine Gammaherpesvirus 68 M2 Gene Is Required for Efficient Reactivation from Latently Infected B Cells
Authors: Herskowitz Jeremy , Jacoby Meagan A. , Speck Samuel H. 
Published: January 2005

ABSTRACT

Murine gammaherpesvirus 68 (γHV68) infection of mice provides a tractable small-animal model system for assessing the requirements for the establishment and maintenance of gammaherpesvirus latency within the lymphoid compartment. The M2 gene product of γHV68 is a latency-associated antigen with no discernible homology to any known proteins. Here we focus on the requirement for the M2 gene in splenic B-cell latency. Our analyses showed the following. (i) Low-dose (100 PFU) inoculation administered via the intranasal route resulted in a failure to establish splenic B-cell latency at day 16 postinfection. (ii) Increasing the inoculation dose to 4 × 10
5
PFU administered via the intranasal route partially restored the establishment of B-cell latency at day 16, but no virus reactivation was detected upon explant into tissue cultures. (iii) Although previous data failed to detect a phenotype of the M2 mutant upon high-dose intraperitoneal inoculation, decreasing the inoculation dose to 100 PFU administered intraperitoneally revealed a splenic B-cell latency phenotype at day 16 that was very similar to the phenotype observed upon high-dose intranasal inoculation. (iv) After low-dose intraperitoneal inoculation, fractionated B-cell populations showed that the M2 mutant virus was able to establish latency in surface immunoglobulin D-negative (sIgD
−
) B cells; by 6 months postinfection, equivalent frequencies of M2 mutant and marker rescue viral genome-positive sIgD
−
B cells were detected. (v) Like the marker rescue virus, the M2 mutant virus also established latency in splenic naive B cells upon low-dose intraperitoneal inoculation, but there was a significant lag in the decay of this latently infected reservoir compared to that seen with the marker rescue virus. (vi) After low-dose intranasal inoculation, by day 42 postinfection, latency was observed in the spleen, although at a frequency significantly lower than that in the marker rescue virus-infected mice; by 3 months postinfection, nearly equivalent levels of viral genome-positive cells were observed in the spleens of marker rescue virus- and M2 mutant virus-infected mice, and these cells were exclusively sIgD
−
B cells. Taken together, these data convincingly demonstrate a role for the M2 gene product in reactivation from splenic B cells and also suggest that disruption of the M2 gene leads to dose- and route-specific defects in the efficient establishment of splenic B-cell latency.
The Proline-Rich Homeodomain (PRH/HEX) Protein Is Down-Regulated in Liver during Infection with Lymphocytic Choriomeningitis Virus
Authors: Djavani Mahmoud , Topisirovic Ivan , Zapata Juan Carlos , Sadowska Mariola , Yang Yida , Rodas Juan , Lukashevich Igor S. , Bogue Clifford W. , Pauza C. David , Borden Katherine L. B. , Salvato Maria S. 
Published: January 2005

ABSTRACT
The proline-rich homeodomain protein, PRH/HEX, participates in the early development of the brain, thyroid, and liver and in the later regenerative processes of damaged liver, vascular endothelial, and hematopoietic cells. A virulent strain of lymphocytic choriomeningitis virus (LCMV-WE) that destroys hematopoietic, vascular, and liver functions also alters the transcription and subcellular localization of PRH. A related virus (LCMV-ARM) that does not cause disease in primates can infect cells without affecting PRH. Biochemical experiments demonstrated the occurrence of binding between the viral RING protein (Z) and PRH, and genetic experiments mapped the PRH-suppressing phenotype to the large (L) segment of the viral genome, which encodes the Z and polymerase genes. The Z protein is clearly involved with PRH, but other viral determinants are needed to relocate PRH and to promote disease. By down-regulating PRH, the arenavirus is able to eliminate the antiproliferative effects of PRH and to promote liver cell division. The interaction of an arenavirus with a homeodomain protein suggests a mechanism for viral teratogenic effects and for the tissue-specific manifestations of arenavirus disease.
Polymorphisms of the XRCC1, XRCC3, & XPDgenes, and colorectal cancer risk: a case-control study in Taiwan
Authors: Yeh Chih-Ching , Sung Fung-Chang , Tang Reiping , Chang-Chieh Chung Rong , Hsieh Ling-Ling 
Published: January 2005

Abstract
Background
Recent studies relating to the association between DNA repair-gene polymorphisms and colorectal cancer risk would, to the best of our knowledge, appear to be very limited. This study was designed to examine the polymorphisms associated with three DNA repair genes, namely: XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln, and investigate their role as susceptibility markers for colorectal cancer.

Methods
We conducted a case-control study including 727 cases of cancer and 736 hospital-based age- and sex-matched healthy controls to examine the role of genetic polymorphisms of three DNA-repair genes (XRCC1, XRCC3 and XPD) in the context of colorectal cancer risk for the Taiwanese population. Genomic DNA isolated from 10 ml whole blood was used to genotype XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln by means of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis.

Results
The risk for colorectal cancer did not appear to differ significantly amongst individuals featuring the XRCC1 399Arg/Arg genotype (OR = 1.18; 95% CI, 0.96–1.45), the XRCC3 241Thr/Thr genotype (OR = 1.25; 95% CI, 0.88–1.79) or the XPD 751Gln allele (OR = 1.20; 95% CI, 0.90–1.61), although individuals featuring a greater number of risk genotypes (genotype with OR greater than 1) did experience a higher risk for colorectal cancer when compared to those who didn't feature any risk genotypes (Trend test P = 0.03). Compared with those individuals who didn't express any putative risk genotypes, individuals featuring all of the putative risk genotypes did experience a significantly greater cancer risk (OR = 2.43, 95% CI = 1.21–4.90), particularly for individuals suffering tumors located in the rectum (OR = 3.18, 95% CI = 1.29–7.82) and diagnosed prior to the age of 60 years (OR = 4.90, 95% CI = 1.72–14.0).

Conclusions
Our results suggest that DNA-repair pathways may simultaneously modulate the risk of colorectal cancer for the Taiwanese population, and, particularly for rectal cancer and younger patients.
The development of a new corporate specific health risk measurement instrument, and its use in investigating the relationship between health and well-being and employee productivity
Authors: Mills Peter R 
Published: January 2005

Abstract
Background
There is a growing body of evidence linking health and well-being to key business issues. Despite this, corporate uptake of workplace health promotion programmes has been slow outside the USA. One possible reason for this is the lack of a generally available health risk measure that is quick and easy to administer and produces data that is rich enough to inform and direct subsequent employee health promotional interventions.

Methods
We report on the development and validation of the health and well-being (HWB) assessment, a free to use health risk appraisal questionnaire that has been specifically developed for use in the corporate setting. The HWB assessment focuses upon modifiable health issues that directly impact upon business drivers. Development involved interviews with business leaders to ascertain their key areas of focus, scientific and general literature review to find evidence for health status having an impact upon these areas, and end user testing.
Three UK-based organisations (insurance, telecommunications and consumer goods sectors) participated in the research. A total of 2224 employees completed the HWB assessment, the short-form 36 (SF-36) and the World Health Organisation Health and Work Performance questionnaire (WHO-HPQ) as part of the validation process.

Results
The HWB assessment is a twenty item questionnaire covering ten areas of health and well-being. Completion of the HWB assessment generates a global health risk score and ten sub-scores corresponding to the ten areas covered. It is easy to use and quick to complete (average completion time was eight minutes) and showed good internal consistency and test-retest reliability. Statistically significant correlations with similar SF-36 variables were observed. A significant negative correlation between HWB score and productivity decrement, as measured by the WHO-HPQ, was observed (r = -0.4). Individuals with HWB scores above the 25th percentile were more likely to achieve workplace productivity standards than those with scores below the 25th percentile (OR 3.62, 95% confidence limits 2.93 – 4.47).

Conclusion
The HWB assessment generates reliable business focused health risk data that can be used to direct and target appropriate interventions within corporate populations. It may also be useful in quantifying the financial impact health status issues have upon organisations.