bluuebunny/crossref_metadata_2025_split huggingface dataset:
The RcsCB His-Asp Phosphorelay System Is Essential To Overcome Chlorpromazine-Induced Stress in
Escherichia coli
Authors: Conter Annie , Sturny Rachel , Gutierrez Claude , Cam Kaymeuang 
Published: July 2002

ABSTRACT

The RcsCB His-Asp phosphorelay system regulates the expression of several genes of
Escherichia coli
, but the molecular nature of the inducing signal is still unknown. We show here that treatment of an exponentially growing culture of
E. coli
with the cationic amphipathic compound chlorpromazine (CPZ) stimulates expression of a set of genes positively regulated by the RcsCB system. This induction is abolished in
rcsB
or
rcsC
mutant strains. In addition, treatment with CPZ inhibits growth. The wild-type strain is able to recover from this inhibition and resume growth after a period of adaptation. In contrast, strains deficient in the RcsCB His-Asp phosphorelay system are hypersensitive to CPZ. These results suggest that cells must express specific RcsCB-regulated genes in order to cope with the CPZ-induced stress. This is the first report of the essential role of the RcsCB system in a stress situation. These results also strengthen the notion that alterations of the cell envelope induce a signal recognized by the RcsC sensor.
Roles of Internal Cysteines in the Function, Localization, and Reactivity of the TraV Outer Membrane Lipoprotein Encoded by the F Plasmid
Authors: Harris Robin L. , Silverman Philip M. 
Published: July 2002

ABSTRACTWe have examined the functional role of two internal cysteine residues of the F-plasmid TraV outer membrane lipoprotein. Each was mutated to a serine separately and together to yield three mutanttraVgenes:traVC10S,traVC18S, andtraVC10S/C18S. All three cysteine mutations complemented atraVmutant for DNA donor activity and for sensitivity to donor-specific bacteriophage; however, when measured by a transduction assay, the donor-specific DNA bacteriophage sensitivities of thetraVC18Sand, especially,traVC10S/C18Smutant strains were significantly less than those of thetraV+andtraVC10Sstrains. Thus, unlike theAgrobacterium tumefaciensT-plasmid-encoded VirB7 outer membrane lipoprotein, TraV does not require either internal cysteine to retain significant biological activity. By Western blot analysis, all three mutant TraV proteins were shown to accumulate in the outer membrane. However, by nonreducing gel electrophoresis, wild-type TraV and especially the TraVC18Smutant were shown to form mixed disulfides with numerous cell envelope proteins. This was not observed with the TraVC10Sor TraVC10S/C18Sproteins. Thus, it appears that TraV C10 is unusually reactive and that this reactivity is reduced by C18, perhaps by intramolecular oxidation. Finally, whereas the TraVC10Sand TraVC18Sproteins fractionated primarily with the outer membrane, as did the wild-type protein, the TraVC10S/C18Sprotein was found in osmotic shock fluid and inner membrane fractions as well as outer membrane fractions. Hence, at least one cysteine is required for the efficient localization of TraV to the outer membrane.
Molecular and Conventional Epidemiology of
Mycobacterium tuberculosis
in Botswana: a Population-Based Prospective Study of 301 Pulmonary Tuberculosis Patients
Authors: Lockman Shahin , Sheppard Jeffery D. , Braden Christopher R. , Mwasekaga Michael J. , Woodley Charles L. , Kenyon Thomas A. , Binkin Nancy J. , Steinman Michael , Montsho Faustina , Kesupile-Reed Matlhatso , Hirschfeldt Colette , Notha Malebogo , Moeti Themba , Tappero Jordan W. 
Published: July 2002

ABSTRACT

Little is known about patterns of tuberculosis (TB) transmission among populations in developing countries with high rates of TB and human immunodeficiency virus (HIV) infection. To examine patterns of TB transmission in such a setting, we performed a population-based DNA fingerprinting study among TB patients in Botswana. Between January 1997 and July 1998, TB patients from four communities in Botswana were interviewed and offered HIV testing. Their
Mycobacterium tuberculosis
isolates underwent DNA fingerprinting using IS
6110
restriction fragment length polymorphism, and those with matching fingerprints were reinterviewed. DNA fingerprints with >5 bands were considered clustered if they were either identical or differed by at most one band, while DNA fingerprints with ≤5 bands were considered clustered only if they were identical. TB isolates of 125 (42%) of the 301 patients with completed interviews and DNA fingerprints fell into 20 different clusters of 2 to 16 patients. HIV status was not associated with clustering. Prior imprisonment was the only statistically significant risk factor for clustering (risk ratio, 1.5; 95% confidence interval, 1.1 to 2.0). In three communities where the majority of eligible patients were enrolled, 26 (11%) of 243 patients overall and 26 (25%) of 104 clustered patients shared both a DNA fingerprint and strong antecedent epidemiologic link. Most of the increasing TB burden in Botswana may be attributable to reactivation of latent infection, but steps should be taken to control ongoing transmission in congregate settings. DNA fingerprinting helps determine loci of TB transmission in the community.
Existence of Hepatitis C Virus in
Culex quinquefasciatus
after Ingestion of Infected Blood: Experimental Approach to Evaluating Transmission by Mosquitoes
Authors: Chang Ting-Tsung , Chang Tsuey-Yu , Chen Cheng-Chen , Young Kung-Chia , Roan Jun-Neng , Lee Yen-Chien , Cheng Pin-Nan , Wu Hua-Lin 
Published: July 2002

ABSTRACT

We used PCR to detect hepatitis C virus (HCV) RNA among supernatants of ground
Culex quinquefasciatus
mosquitoes that (i) had been fed HCV-positive blood, (ii) had been intrathoracically inoculated with HCV-positive blood, or (iii) were from homes of hepatitis C patients. HCV RNA was detectable under all three conditions, but it did not replicate in mosquitoes and was not detectably transmitted during feeding.
Multicenter Evaluation of Fully Automated BACTEC Mycobacteria Growth Indicator Tube 960 System for Susceptibility Testing of
Mycobacterium tuberculosis
Authors: Bemer Pascale , Palicova Frantiska , Rüsch-Gerdes Sabine , Drugeon Henri B. , Pfyffer Gaby E. 
Published: July 2002

ABSTRACT

The reliability of the BACTEC Mycobacteria Growth Indicator Tube (MGIT) 960 system for testing of
Mycobacterium tuberculosis
susceptibility to the three front-line drugs (isoniazid [INH], rifampin [RIF], and ethambutol [EMB]) plus streptomycin (STR) was compared to that of the BACTEC 460 TB system. The proportion method was used to resolve discrepant results by an independent arbiter. One hundred and ten strains were tested with an overall agreement of 93.5%. Discrepant results were obtained for seven strains (6.4%) with INH (resistant by BACTEC MGIT 960; susceptible by BACTEC 460 TB), for one strain (0.9%) with RIF (resistant by BACTEC MGIT 960; susceptible by BACTEC 460 TB), for seven strains (6.4%) with EMB (six resistant by BACTEC MGIT 960 and susceptible by BACTEC 460 TB; one susceptible by BACTEC MGIT 960 and resistant by BACTEC 460 TB), and for 19 strains (17.3%) with STR (resistant by BACTEC MGIT 960 and susceptible by BACTEC 460 TB). After resolution of discrepant results, the sensitivity of the BACTEC MGIT 960 system was 100% for all four drugs and specificity ranged from 89.8% for STR to 100% for RIF. Turnaround times were 4.6 to 11.7 days (median, 6.5 days) for BACTEC MGIT 960 and 4.0 to 10.0 days (median, 7.0 days) for BACTEC 460 TB. These data demonstrate that the fully automated and nonradiometric BACTEC MGIT 960 system is an accurate method for rapid susceptibility testing of
M. tuberculosis
.
Polymorphisms of
Helicobacter pylori
HP0638 Reflect Geographic Origin and Correlate with
cagA
Status
Authors: Ando T. , Peek R. M. , Pride D. , Levine S. M. , Takata T. , Lee Y.-C. , Kusugami K. , van der Ende A. , Kuipers E. J. , Kusters J. G. , Blaser M. J. 
Published: July 2002

ABSTRACT

Since the associations between
Helicobacter pylori
genotype and disease differ in Asia and the West, we investigated the correlation between HP0638, encoding an outer membrane protein, and potential markers of virulence (
cagA
,
vacA
, and
iceA
). For 109 strains from nine countries, the status of
cagA
,
vacA
, and
iceA
was determined by PCR and/or a line probe assay. We also studied 18 strains from 8 patients (parents and 6 daughters) from a Dutch family and paired strains collected on average 8 years apart from 11 patients. When the HP0638 signal sequences were amplified by PCR and DNA sequence determinations were performed, 89 (96%) of 93
cagA
-positive strains had HP0638 in frame, versus none (0%) of 16
cagA
-negative strains (
P
< 0.001). Among strains in which HP0638 was in frame, a six-CT dinucleotide repeat pattern was dominant in Western countries (23 of 33 strains [70%]), while a pattern of three CT repeats with another CT after four T’s (3 + 1-CT-repeat pattern) was dominant in East Asia (31 of 46 strains [67%]); however, specific CT repeat patterns did not correlate with clinical outcome. HP0638 phylogenetic trees also showed geographic characters. The HP0638 frame status and CT dinucleotide repeat patterns were identical for 9 of 11 pairs of strains obtained on average 8 years apart from individuals and the 15 strains obtained from the mother and all six daughters. Thus, HP0638 frame status and
cagA
status are strongly correlated. The CT dinucleotide repeat pattern in the putative HP0638 signal sequence has geographic characters and appears stable in particular patients and families over a period of years. Analysis of HP0638 CT polymorphisms may serve as a new typing system to discriminate
H
.
pylori
isolates for epidemiological purposes.
Molecular Epidemiology and Drug Resistance of
Mycobacterium tuberculosis
Isolates from Ethiopian Pulmonary Tuberculosis Patients with and without Human Immunodeficiency Virus Infection
Authors: Bruchfeld Judith , Aderaye Getachew , Palme Ingela Berggren , Bjorvatn Bjarne , Ghebremichael Solomon , Hoffner Sven , Lindquist Lars 
Published: July 2002

ABSTRACT

We have analyzed the molecular epidemiology and drug resistance of 121
Mycobacterium tuberculosis
isolates from consecutive patients with culture-positive pulmonary tuberculosis attending a university hospital outpatient department in Addis Ababa, Ethiopia. Restriction fragment length polymorphism analysis and spoligotyping were used to analyze the DNA fingerprinting patterns. Fifty-one (41.2%) of the isolates were found in 13 clusters with two or more identical DNA patterns. Two such clusters contained 49.0% of all clustered isolates. In a multivariate logistic regression model, human immunodeficiency virus (HIV)-positive serostatus was significantly associated with clustering of isolates for patients of both sexes (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.17 to 5.80). There was a trend toward increased clustering of isolates from tuberculous women residing in Addis Ababa (OR, 2.10; 95% CI, 0.85 to 5.25). In total, 17 of 121 isolates (14.0%) were resistant to one or more of the antituberculosis drugs isoniazid (8.3%), streptomycin (7.4%), rifampin (2.5%), and ethambutol (1.7%). The high rate of drug-resistant isolates (29.6%) coincided with the peak prevalence of HIV infection (77.8%) in patients 35 to 44 years old. The majority (62.5%) of resistant isolates in this group were found within clusters. The simultaneous accumulation of certain bacterial clones in a patient population likely reflects recent transmission. Hence, we conclude that tuberculosis is commonly caused by recent infection with
M
.
tuberculosis
in HIV-positive Ethiopian patients. Furthermore, with the rapidly increasing prevalence of HIV infection in Ethiopia, the burden of tuberculosis, including drug-resistant tuberculosis, is likely to increase. Strengthening of classical tuberculosis control measures by promoting active case finding among HIV-positive adults with tuberculosis is warranted to reduce rates of transmission.
Epstein-Barr Virus gH Is Essential for Penetration of B Cells but Also Plays a Role in Attachment of Virus to Epithelial Cells
Authors: Molesworth Sara J. , Lake Cathleen M. , Borza Corina M. , Turk Susan M. , Hutt-Fletcher Lindsey M. 
Published: July 2002

ABSTRACT
Entry of Epstein-Barr virus (EBV) into B cells is initiated by attachment of glycoprotein gp350 to the complement receptor type 2 (CR2). A complex of three glycoproteins, gH, gL, and gp42, is subsequently required for penetration. Gp42 binds to HLA class II, which functions as an entry mediator or coreceptor and, by analogy with other herpesviruses, gH is then thought to be involved virus-cell fusion. However, entry of virus into epithelial cells is thought to be different. It can be initiated by attachment by an unknown glycoprotein in the absence of CR2. There is no interaction between gp42 and HLA class II and instead a distinct complex of only the two glycoproteins gH and gL interacts with a novel entry mediator. Again, by analogy with other viruses gH is thought to be critical to fusion. To investigate further the different roles of gH in infection of the two cell types and to examine its influence on the assembly of the gH-gL-gp42 complex, we constructed two viruses, one in which the gH open reading frame was interrupted by a cassette expressing a neomycin resistance gene and the gene for green fluorescent protein and one as a control in which the neighboring nonessential thymidine kinase gene was interrupted with the same cassette. Virus lacking gH exited from cells normally, although loss of gH resulted in rapid turnover of gL and gp42 as well. The virus bound normally to B lymphocytes but could not infect them unless cells and bound virus were treated with polyethylene glycol to induce fusion. In contrast, virus that lacked the gH complex was impaired in attachment to epithelial cells and the effects of monoclonal antibodies to gH implied that this resulted from loss of gH rather than other members of the complex. These results suggest a role for gH in both attachment and penetration into epithelial cells.
Effects of Palmitoylation of Replicase Protein nsP1 on Alphavirus Infection
Authors: Ahola Tero , Kujala Pekka , Tuittila Minna , Blom Titta , Laakkonen Pirjo , Hinkkanen Ari , Auvinen Petri 
Published: July 2002

ABSTRACT
The membrane-associated alphavirus RNA replication complex contains four virus-encoded subunits, the nonstructural proteins nsP1 to nsP4. Semliki Forest virus (SFV) nsP1 is hydrophobically modified by palmitoylation of cysteines 418 to 420. Here we show that Sindbis virus nsP1 is also palmitoylated on the same site (cysteine 420). When mutations preventing nsP1 palmitoylation were introduced into the genomes of these two alphaviruses, the mutant viruses remained viable and replicated to high titers, although their growth was slightly delayed. The subcellular distribution of palmitoylation-defective nsP1 was altered in the mutant: it no longer localized to filopodial extensions, and a fraction of it was soluble. The ultrastructure of the alphavirus replication sites appeared normal, and the localization of the other nonstructural proteins was unaltered in the mutants. In both wild-type- and mutant-virus-infected cells, SFV nsP3 and nsP4 could be extracted from membranes only by alkaline solutions whereas the nsP2-membrane association was looser. Thus, the membrane binding properties of the alphavirus RNA replication complex were not determined by the palmitoylation of nsP1. The nsP1 palmitoylation-defective alphaviruses produced normal plaques in several cell types, but failed to give rise to plaques in HeLa cells, although they induced normal apoptosis of these cells. The SFV mutant was apathogenic in mice: it caused blood viremia, but no infectious virus was detected in the brain.
Synergistic Upregulation of Interleukin-8 Secretion from Pulmonary Epithelial Cells by Direct and Monocyte-Dependent Effects of Respiratory Syncytial Virus Infection
Authors: Thomas Lynette H. , Wickremasinghe Melissa I. Y. , Sharland Mike , Friedland Jon S. 
Published: July 2002

ABSTRACTRespiratory syncytial virus (RSV) infection is the major cause of severe bronchiolitis in infants. Pathology of this infection is partly due to excessive proinflammatory leukocyte influx mediated by chemokines. Although direct infection of the respiratory epithelium by RSV may induce chemokine secretion, little is known about the role of cytokine networks. We investigated the effects of conditioned medium (CM) from RSV-infected monocytes (RSV-CM) on respiratory epithelial (A549) cell chemokine release. RSV-CM, but not control CM (both at a 1:5 dilution), stimulated interleukin-8 (IL-8) secretion from A549 cells within 2 h, and secretion increased over 72 h to 11,360 ± 1,090 pg/ml without affecting cell viability. In contrast, RSV-CM had only a small effect on RANTES secretion. RSV-CM interacted with direct RSV infection to synergistically amplify IL-8 secretion from respiratory epithelial cells (levels of secretion at 48 h were as follows: RSV-CM alone, 8,140 ± 2,160 pg/ml; RSV alone, 12,170 ± 300 pg/ml; RSV-CM plus RSV, 27,040 ± 5,260 pg/ml;P< 0.05). RSV-CM induced degradation of IκBα within 5 min but did not affect IκBβ. RSV-CM activated transient nuclear binding of NF-κB within 1 h, while activation of NF-IL6 was delayed until 8 h and was still detectable at 24 h. Promoter-reporter analysis demonstrated that NF-κB binding was essential and that NF-IL6 was important for IL-8 promoter activity in RSV-CM-activated cells. Blocking experiments revealed that the effects of RSV-CM depended on monocyte-derived IL-1 but that tumor necrosis factor alpha was not involved in this network. In summary, RSV infection of monocytes results in and amplifies direct RSV-mediated IL-8 secretion from respiratory epithelial cells by an NF-κB-dependent, NF-IL6-requiring mechanism.
The Valine Anticodon and Valylatability of
Peanut Clump Virus
RNAs Are Not Essential but Provide a Modest Competitive Advantage in Plants
Authors: Matsuda Daiki , Dunoyer Patrice , Hemmer Odile , Fritsch Christiane , Dreher Theo W. 
Published: July 2002

ABSTRACT

The role of valine aminoacylation of the two genomic RNAs of
Peanut clump virus
(PCV) was studied by comparing the amplification in vivo of RNAs with GAC, GΔC, or CCA anticodons in the tRNA-like structure (TLS) present at the 3′ end of each viral RNA. The PCV RNA1 TLS of isolate PCV2 possesses a GAC anticodon and is capable of highly efficient valylation, whereas the RNA2 TLS has a GΔC anticodon that does not support valylation. The presence in RNA1 of GΔC or CCA anticodons that conferred nonvalylatability resulted in about 2- to 4-fold and a 14- to 24-fold reduction, respectively, in RNA accumulations in tobacco BY-2 protoplasts inoculated with the RNA1 variants together with wild-type RNA2(GΔC). No differences in RNA levels were observed among protoplasts inoculated with the three variant RNA2s in the presence of wild-type RNA1(GAC). All combinations of valylatable and nonvalylatable RNAs 1 and 2 were similarly infectious in
Nicotiana benthamiana
plants, and viral RNAs accumulated to similar levels; all input TLS sequences were present unchanged in apical leaves. In direct competition experiments in
N. benthamiana
plants, however, both RNA1 and RNA2 with GAC valylatable anticodons outcompeted the nonvalylatable variants. We conclude that valylation provides a small but significant replicational advantage to both PCV RNAs. Sequence analysis of the TLS from RNA2 of a second PCV isolate, PO2A, revealed the presence of an intact GAC valine anticodon, suggesting that the differential valylation of the genomic RNAs of isolate PCV2 is not a general characteristic of PCV.
Genetic Determinants of Altered Virulence of Taiwanese Foot-and-Mouth Disease Virus
Authors: Beard Clayton W. , Mason Peter W. 
Published: July 2002

ABSTRACT
In 1997, a devastating outbreak of foot-and-mouth disease (FMD) in Taiwan was caused by a serotype O virus (referred to here as OTai) with atypical virulence. It produced high morbidity and mortality in swine but did not affect cattle. We have defined the genetic basis of the species specificity of OTai by evaluating the properties of genetically engineered chimeric viruses created from OTai and a bovine-virulent FMD virus. These studies have shown that an altered nonstructural protein, 3A, is a primary determinant of restricted growth on bovine cells in vitro and significantly contributes to bovine attenuation of OTai in vivo.
Loss of Heterozygosity at theInk4a/ArfLocus Facilitates Abelson Virus Transformation of Pre-B Cells
Authors: Mostecki Justin , Halgren Anne , Radfar Arash , Sachs Zohar , Ravitz James , Thome Kelly C. , Rosenberg Naomi 
Published: July 2002

ABSTRACTIn many tumor systems, analysis of cells for loss of heterozygosity (LOH) has helped to clarify the role of tumor suppressor genes in oncogenesis. Two important tumor suppressor genes,p53and theInk4a/Arflocus, play central roles in the multistep process of Abelson murine leukemia virus (Ab-MLV) transformation. p53 and the p53 regulatory protein, p19Arf, are required for the apoptotic crisis that characterizes the progression of primary transformed pre-B cells to fully malignant cell lines. To search for other tumor suppressor genes which may be involved in the Ab-MLV transformation process, we used endogenous proviral markers and simple-sequence length polymorphism analysis to screen Abelson virus-transformed pre-B cells for evidence of LOH. Our survey reinforces the role of the p53-p19 regulatory pathway in transformation; 6 of 58 cell lines tested had lost sequences on mouse chromosome 4, including theInk4a/Arflocus. Consistent with this pattern, a high frequency of primary pre-B-cell transformants derived fromInk4a/Arf+/− mice became established cell lines. In addition, half of them retained the single copy of the locus when the transformation process was complete. These data demonstrate that a single copy of theInk4a/Arflocus is not sufficient to fully mediate the effects of these genes on transformation.
Human Receptor for Measles Virus (CD46) Enhances Nitric Oxide Production and Restricts Virus Replication in Mouse Macrophages by Modulating Production of Alpha/Beta Interferon
Authors: Katayama Yuko , Hirano Akiko , Wong Timothy C. 
Published: July 2002

ABSTRACTComplement regulatory protein CD46 is a human cell receptor for measles virus (MV). In this study, we investigated why mouse macrophages expressing human CD46 restricted MV replication and produced higher levels of nitric oxide (NO) in response to MV and gamma interferon (IFN-γ). Treatment of MV-infected CD46-expressing mouse macrophages with antibodies against IFN-α/β blocked NO production. Antibodies against IFN-α/β also inhibited the augmenting effect of MV on IFN-γ-induced NO production in CD46-expressing mouse macrophages. These antibodies did not affect NO production induced by IFN-γ alone. These data suggest that MV enhances NO production in CD46-expressing mouse macrophages through action of IFN-α/β. Mouse macrophages expressing a human CD46 mutant lacking the cytoplasmic domains were highly susceptible to MV. These cells produced much lower levels of NO and IFN-α/β upon infection by MV, suggesting the CD46 cytoplasmic domains enhanced IFN-α/β production. When mouse macrophages expressing tailless human CD46 were exposed to culture medium from MV-infected mouse macrophages expressing intact human CD46, viral protein synthesis and development of cytopathic effects were suppressed. Pretreating the added culture medium with antibodies against IFN-α/β abrogated these antiviral effects. Taken together, these findings suggest that expression of human CD46 in mouse macrophages enhances production of IFN-α/β in response to MV infection, and IFN-α/β synergizes with IFN-γ to enhance NO production and restrict viral protein synthesis and virus replication. This novel function of human CD46 in mouse macrophages requires the CD46 cytoplasmic domains.