bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interplay among Cyclic Diguanylate, HapR, and the General Stress Response Regulator (RpoS) in the Regulation of Vibrio cholerae Hemagglutinin/Protease
Authors: Wang Hongxia , Wu Jian-He , Ayala Julio C. , Benitez Jorge A. , Silva Anisia J. 
Published: October 2011

ABSTRACT

Vibrio cholerae
secretes the Zn-dependent metalloprotease hemagglutinin (HA)/protease (mucinase), which is encoded by
hapA
and displays a broad range of potential pathogenic activities. Expression of HA/protease has a stringent requirement for the quorum-sensing regulator HapR and the general stress response regulator RpoS. Here we report that the second messenger cyclic diguanylic acid (c-di-GMP) regulates the production of HA/protease in a negative manner. Overexpression of a diguanylate cyclase to increase the cellular c-di-GMP pool resulted in diminished expression of HA/protease and its positive regulator, HapR. The effect of c-di-GMP on HapR was independent of LuxO but was abolished by deletion of the c-di-GMP binding protein VpsT, the LuxR-type regulator VqmA, or a single-base mutation in the
hapR
promoter that prevents autorepression. Though expression of HapR had a positive effect on RpoS biosynthesis, direct manipulation of the c-di-GMP pool at a high cell density did not significantly impact RpoS expression in the wild-type genetic background. In contrast, increasing the c-di-GMP pool severely inhibited RpoS expression in a Δ
hapR
mutant that is locked in a regulatory state mimicking low cell density. Based on the above findings, we propose a model for the interplay between HapR, RpoS, and c-di-GMP in the regulation of HA/protease expression.
Bacteriophage F336 Recognizes the Capsular Phosphoramidate Modification of Campylobacter jejuni NCTC11168
Authors: Sørensen Martine C. Holst , van Alphen Lieke B. , Harboe Anne , Li Jianjun , Christensen Bjarke Bak , Szymanski Christine M. , Brøndsted Lone 
Published: October 2011

ABSTRACT

Bacteriophages infecting the food-borne human pathogen
Campylobacter jejuni
could potentially be exploited to reduce bacterial counts in poultry prior to slaughter. This bacterium colonizes the intestinal tract of poultry in high numbers, and contaminated poultry meat is regarded as the major source of human campylobacteriosis. In this study, we used phage F336 belonging to the
Myoviridae
family to select a
C. jejuni
NCTC11168 phage-resistant strain, called 11168R, with the aim of investigating the mechanisms of phage resistance. We found that phage F336 has reduced adsorption to 11168R, thus indicating that the receptor is altered. While proteinase K-treated
C. jejuni
cells did not affect adsorption, periodate treatment resulted in reduced adsorption, suggesting that the phage binds to a carbohydrate moiety. Using high-resolution magic angle spinning nuclear magnetic resonance (NMR) spectroscopy, we found that 11168R lacks an
O
-methyl phosphoramidate (MeO
P
N) moiety attached to the Gal
f
NAc on the capsular polysaccharide (CPS), which was further confirmed by mass spectroscopy. Sequence analysis of 11168R showed that the potentially hypervariable gene
cj1421
, which encodes the Gal
f
NAc MeO
P
N transferase, contains a tract of 10 Gs, resulting in a nonfunctional gene product. However, when 11168R reverted back to phage sensitive,
cj1421
contained 9 Gs, and the Gal
f
NAc MeO
P
N was regained in this strain. In summary, we have identified the phase-variable MeO
P
N moiety, a common component of the diverse capsular polysaccharides of
C. jejuni
, as a novel receptor of phages infecting this bacterium.
Cyclohexane-1,2-Dione Hydrolase from Denitrifying Azoarcus sp. Strain 22Lin, a Novel Member of the Thiamine Diphosphate Enzyme Family
Authors: Steinbach Alma K. , Fraas Sonja , Harder Jens , Tabbert Anja , Brinkmann Henner , Meyer Axel , Ermler Ulrich , Kroneck Peter M. H. 
Published: October 2011

ABSTRACT

Alicyclic compounds with hydroxyl groups represent common structures in numerous natural compounds, such as terpenes and steroids. Their degradation by microorganisms in the absence of dioxygen may involve a C—C bond ring cleavage to form an aliphatic intermediate that can be further oxidized. The cyclohexane-1,2-dione hydrolase (CDH) (EC 3.7.1.11) from denitrifying
Azoarcus
sp. strain 22Lin, grown on cyclohexane-1,2-diol as a sole electron donor and carbon source, is the first thiamine diphosphate (ThDP)-dependent enzyme characterized to date that cleaves a cyclic aliphatic compound. The degradation of cyclohexane-1,2-dione (CDO) to 6-oxohexanoate comprises the cleavage of a C—C bond adjacent to a carbonyl group, a typical feature of reactions catalyzed by ThDP-dependent enzymes. In the subsequent NAD
+
-dependent reaction, 6-oxohexanoate is oxidized to adipate. CDH has been purified to homogeneity by the criteria of gel electrophoresis (a single band at ∼59 kDa; calculated molecular mass, 64.5 kDa); in solution, the enzyme is a homodimer (∼105 kDa; gel filtration). As isolated, CDH contains 0.8 ± 0.05 ThDP, 1.0 ± 0.02 Mg
2+
, and 1.0 ± 0.015 flavin adenine dinucleotide (FAD) per monomer as a second organic cofactor, the role of which remains unclear. Strong reductants, Ti(III)-citrate, Na
+
-dithionite, and the photochemical 5-deazaflavin/oxalate system, led to a partial reduction of the FAD chromophore. The cleavage product of CDO, 6-oxohexanoate, was also a substrate; the corresponding cyclic 1,3- and 1,4-diones did not react with CDH, nor did the
cis
- and
trans
-cyclohexane diols. The enzymes acetohydroxyacid synthase (AHAS) from
Saccharomyces cerevisiae
, pyruvate oxidase (POX) from
Lactobacillus plantarum
, benzoylformate decarboxylase from
Pseudomonas putida
, and pyruvate decarboxylase from
Zymomonas mobilis
were identified as the closest relatives of CDH by comparative amino acid sequence analysis, and a ThDP binding motif and a 2-fold Rossmann fold for FAD binding could be localized at the C-terminal end and central region of CDH, respectively. A first mechanism for the ring cleavage of CDO is presented, and it is suggested that the FAD cofactor in CDH is an evolutionary relict.
Deletion Strains Reveal Metabolic Roles for Key Elemental Sulfur-Responsive Proteins in Pyrococcus furiosus
Authors: Bridger Stephanie L. , Clarkson Sonya M. , Stirrett Karen , DeBarry Megan B. , Lipscomb Gina L. , Schut Gerrit J. , Westpheling Janet , Scott Robert A. , Adams Michael W. W. 
Published: October 2011

ABSTRACT

Transcriptional and enzymatic analyses of
Pyrococcus furiosus
previously indicated that three proteins play key roles in the metabolism of elemental sulfur (S
0
): a membrane-bound oxidoreductase complex (MBX), a cytoplasmic coenzyme A-dependent NADPH sulfur oxidoreductase (NSR), and sulfur-induced protein A (SipA). Deletion strains, referred to as MBX1, NSR1, and SIP1, respectively, have now been constructed by homologous recombination utilizing the uracil auxotrophic COM1 parent strain (Δ
pyrF
). The growth of all three mutants on maltose was comparable without S
0
, but in its presence, the growth of MBX1 was greatly impaired while the growth of NSR1 and SIP1 was largely unaffected. In the presence of S
0
, MBX1 produced little, if any, sulfide but much more acetate (per unit of protein) than the parent strain, demonstrating that MBX plays a critical role in S
0
reduction and energy conservation. In contrast, comparable amounts of sulfide and acetate were produced by NSR1 and the parent strain, indicating that NSR is not essential for energy conservation during S
0
reduction. Differences in transcriptional responses to S
0
in NSR1 suggest that two sulfide dehydrogenase isoenzymes provide a compensatory NADPH-dependent S
0
reduction system. Genes controlled by the S
0
-responsive regulator SurR were not as highly regulated in MBX1 and NSR1. SIP1 produced the same amount of acetate but more sulfide than the parent strain. That SipA is not essential for growth on S
0
indicates that it is not required for detoxification of metal sulfides, as previously suggested. A model is proposed for S
0
reduction by
P. furiosus
with roles for MBX and NSR in bioenergetics and for SipA in iron-sulfur metabolism.
Hopanoid Production Is Required for Low-pH Tolerance, Antimicrobial Resistance, and Motility in Burkholderia cenocepacia
Authors: Schmerk Crystal L. , Bernards Mark A. , Valvano Miguel A. 
Published: October 2011

ABSTRACT

Hopanoids are pentacyclic triterpenoids that are thought to be bacterial surrogates for eukaryotic sterols, such as cholesterol, acting to stabilize membranes and to regulate their fluidity and permeability. To date, very few studies have evaluated the role of hopanoids in bacterial physiology. The synthesis of hopanoids depends on the enzyme squalene-hopene cyclase (Shc), which converts the linear squalene into the basic hopene structure. Deletion of the 2 genes encoding Shc enzymes in
Burkholderia cenocepacia
K56-2,
BCAM2831
and
BCAS0167
, resulted in a strain that was unable to produce hopanoids, as demonstrated by gas chromatography and mass spectrometry. Complementation of the Δ
shc
mutant with only
BCAM2831
was sufficient to restore hopanoid production to wild-type levels, while introducing a copy of
BCAS0167
alone into the Δ
shc
mutant produced only very small amounts of the hopanoid peak. The Δ
shc
mutant grew as well as the wild type in medium buffered to pH 7 and demonstrated no defect in its ability to survive and replicate within macrophages, despite transmission electron microscopy (TEM) revealing defects in the organization of the cell envelope. The Δ
shc
mutant displayed increased sensitivity to low pH, detergent, and various antibiotics, including polymyxin B and erythromycin. Loss of hopanoid production also resulted in severe defects in both swimming and swarming motility. This suggests that hopanoid production plays an important role in the physiology of
B. cenocepacia
.
Regulation of Transcription by SMU.1349, a TetR Family Regulator, in Streptococcus mutans
Authors: Chattoraj Partho , Mohapatra Saswat Sourav , Rao J. L. Uma Maheswar , Biswas Indranil 
Published: October 2011

ABSTRACTThe TetR family of transcriptional regulators is ubiquitous in bacteria, where it plays an important role in bacterial gene expression.Streptococcus mutans, a Gram-positive pathogen considered to be the primary etiological agent in the formation of dental caries, encodes at least 18 TetR regulators. Here we characterized one such TetR regulator, SMU.1349, encoded by the TnSmu2 operon, which appeared to be acquired by the organism via horizontal gene transfer. SMU.1349 is transcribed divergently from the rest of the genes encoded by the operon. By the use of a transcriptional reporter system and semiquantitative reverse transcription-PCR (RT-PCR), we demonstrated that SMU.1349 activates the transcription of several genes that are encoded within the TnSmu2 operon. Gel mobility shift and DNase I footprinting assays with purified SMU.1349 protein demonstrated binding to the intergenic region between SMU.1349 and the TnSmu2 operon; therefore, SMU.1349 is directly involved in gene transcription. Using purifiedS. mutansRpoD andEscherichia coliRNA polymerase, we also demonstrated in anin vitrotranscription assay that SMU.1349 could activate transcription from the TnSmu2 operon promoter. Furthermore, we showed that SMU.1349 could also repress transcription from its own promoter by binding to the intergenic region, suggesting that SMU.1349 acts as both an activator and a repressor. Thus, unlike most of the TetR family proteins, which generally function as transcriptional repressors, SMU.1349 is unique in that it can function as both.
Adeno-Associated Virus Activates an Innate Immune Response in Normal Human Cells but Not in Osteosarcoma Cells
Authors: Laredj Leila N. , Beard Peter 
Published: September 2011

ABSTRACT

Adeno-associated virus (AAV) is a small, DNA-containing
dependovirus
with promising potential as a gene delivery vehicle. Given the variety of applications of AAV-based vectors in the treatment of genetic disorders, numerous studies have focused on the immunogenicity of recombinant AAV. In general, AAV vectors appear not to induce strong inflammatory responses. We have found that AAV2, when it infects the osteosarcoma cells U2OS, can initiate part of its replicative cycle in the absence of helper virus. This does not occur in untransformed cells. We set out to test whether the cellular innate antiviral defenses control this susceptibility and found that, in nonimmune normal human fibroblasts, AAV2 induces type I interferon production and release and the accumulation of nuclear promyelocytic leukemia bodies. AAV fails to mobilize this defense pathway in the U2OS cells. This permissiveness is in large part due to impairment of the viral sensing machinery in these cells. Our investigations point to Toll-like receptor 9 as a potential intracellular sensor that detects AAV2 and triggers the antiviral state in AAV-infected untransformed cells. Efficient sensing of the AAV genome and the ensuing activation of an innate antiviral response are thus crucial cellular events dictating the parvovirus infectivity in host cells.
Viusid, a nutritional supplement, increases survival and reduces disease progression in HCV-related decompensated cirrhosis: a randomised and controlled trial
Authors: Vilar Gomez Eduardo , Sanchez Rodriguez Yoan , Torres Gonzalez Ana , Calzadilla Bertot Luis , Arus Soler Enrique , Martinez Perez Yadina , Yasells Garcia Ali , Abreu Vazquez Maria del Rosario 
Published: October 2011

ObjectivesViusid is a nutritional supplement with recognised antioxidant and immunomodulatory properties which could have beneficial effects on cirrhosis-related clinical outcomes such as survival, disease progression and development of hepatocellular carcinoma (HCC). This study evaluated the efficacy and safety of viusid in patients with HCV-related decompensated cirrhosis.DesignA randomised double-blind and placebo-controlled study was conducted in a tertiary care academic centre (National Institute of Gastroenterology, Havana, Cuba). The authors randomly assigned 100 patients with HCV-related decompensated cirrhosis to receive viusid (three oral sachets daily, n=50) or placebo (n=50) during 96 weeks. The primary outcome of the study was overall survival at 96 weeks, and the secondary outcomes included time to disease progression, time to HCC diagnosis, time to worsening of the prognostic scoring systems Child–Pugh and Model for End-Stage Liver Disease, and time to a new occurrence or relapse for each one of the main clinical complications secondary to portal hypertension at 96 weeks.ResultsViusid led to a significant improvement in overall survival (90%) versus placebo (74%) (HR 0.27, 95% CI 0.08 to 0.92; p=0.036). A similar improvement in disease progression was seen in viusid-treated patients (28%), compared with placebo-treated patients (48%) (HR 0.47, 95% CI 0.22 to 0.89; p=0.044). However, the beneficial effects of viusid were wholly observed among patients with Child–Pugh classes B or C, but not among patients with Child–Pugh class A. The cumulative incidence of HCC was significantly reduced in patients treated with viusid (2%) as compared with placebo (12%) (HR 0.15, 95% CI 0.019 to 0.90; p=0.046). Viusid was well tolerated.ConclusionsThe results indicate that treatment with viusid leads to a notable improvement in overall clinical outcomes such as survival, disease progression and development of HCC in patients with HCV-related decompensated cirrhosis.Trial registration numberhttp://ClinicalTrials.gov(NCT00502086).
Suicide-related discussions with depressed primary care patients in the USA: gender and quality gaps. A mixed methods analysis
Authors: Vannoy Steven D , Robins Lynne S 
Published: October 2011

ObjectiveTo characterise suicide-risk discussions in depressed primary-care patients.DesignSecondary analysis of recordings and self reports by physicians and patients. Descriptive statistics of depression and suicide-related discussion, with qualitative extraction of disclosure, enquiry and physician response.Setting12 primary-care clinics between July 2003 and March 2005.Participants48 primary-care physicians and 1776 adult patients.MeasuresPresence of depression or suicide-related discussions during the encounter; patient and physician demographics; depression symptom severity and suicide ideation as measured by the Patient Health Questionnaire (PHQ9); physician's decision-making style as measured by the Medical Outcomes Study Participatory Decision-Making Scale; support for autonomy as measured by the Health Care Climate Questionnaire; trust in their physician as measured by the Primary Care Assessment Survey; physician response to suicide-related enquiry or disclosure.ResultsOf the 1776 encounters, 128 involved patients scoring >14 on the PHQ9. These patients were seen by 43 of the 48 physicians. Suicide ideation was endorsed by 59% (n=75). Depression was discussed in 52% of the encounters (n=66). Suicide-related discussion occurred in only 11% (n=13) of encounters. 92% (n=12) of the suicide discussions occurred with patients scoring <2 on PHQ9 item 9. Suicide was discussed in only one encounter with a male. Variation in elicitation and response styles demonstrated preferred and discouraged interviewing strategies.ConclusionsSuicide ideation is present in a significant proportion of depressed primary care patients but rarely discussed. Men, who carry the highest risk for suicide, are unlikely to disclose their ideation or be asked about it. Patient-centred communication and positive healthcare climate do not appear to increase the likelihood of suicide related discussion. Physicians should be encouraged to ask about suicide ideation in their depressed patients and, when disclosure occurs, facilitate discussion and develop targeted treatment plans.
Is there an association between wheezing and constipation in preschool children? Explanations from a longitudinal birth cohort
Authors: Kiefte-de Jong J C , Lebon A , Jaddoe V W V , Hofman A , de Jongste J C , Moll H A 
Published: October 2011

ObjectiveTo assess whether wheezing and atopic dermatitis were associated with constipation in preschool children and to what extent shared risk factors contribute to this relationship.MethodsA population-based sample of 4651 preschool children was used. At the age of 24, 36 and 48 months, a parental report of functional constipation was available according to the Rome II criteria, and data on atopic dermatitis and wheezing were available using age-adapted questionnaires from the International Study of Asthma and Allergies in Childhood. Stepwise multivariate analyses were performed to assess whether body mass index, infection exposure, food allergy and infant nutrition, and parental stress explained the association between wheezing, atopic dermatitis and constipation.ResultsOut of 4651 children, 12–17% had functional constipation between 24 and 48 months. Symptoms of wheezing decreased from 20% to 12% and atopic dermatitis decreased from 30% to 18% at the age of 24 and 48 months respectively. Between the age of 24 and 48 months, wheezing symptoms were significantly associated with functional constipation (OR 1.17; 1.02 to 1.34) but these results were mainly explained by the child's exposure to infections and use of antibiotics (adjusted odds ratio 1.08; 95% CI 0.95 to 1.24). No significant association was found between symptoms of atopic dermatitis and functional constipation (OR 1.08; 95% CI 0.94 to 1.23).ConclusionsThese findings suggest that functional constipation coexists with wheezing in childhood but is mainly explained by the child's infection exposure and use of antibiotics. Therefore, an independent association between respiratory symptoms and functional bowel disorders as suggested in previous studies is questionable.
A cluster randomised controlled trial of a comprehensive accreditation intervention to reduce alcohol consumption at community sports clubs: study protocol: Figure 1
Authors: Kingsland Melanie , Wolfenden Luke , Rowland Bosco C , Tindall Jennifer , Gillham Karen E , McElduff Patrick , Rogerson John C , Wiggers John H 
Published: October 2011

IntroductionExcessive alcohol consumption is responsible for considerable harm from chronic disease and injury. Within most developed countries, members of sporting clubs consume alcohol at levels above that of communities generally. Despite the potential benefits of interventions to address alcohol consumption in sporting clubs, there have been no randomised controlled trials to test the effectiveness of these interventions. The aim of this study is to examine the effectiveness of a comprehensive accreditation intervention with community football clubs (Rugby League, Rugby Union, soccer/association football and Australian Rules football) in reducing excessive alcohol consumption by club members.Methods and analysisThe study will be conducted in New South Wales, Australia, and employ a cluster randomised controlled trial design. Half of the football clubs recruited to the trial will be randomised to receive an intervention implemented over two and a half winter sporting seasons. The intervention is based on social ecology theory and is comprehensive in nature, containing multiple elements designed to decrease the supply of alcohol to intoxicated members, cease the provision of cheap and free alcohol, increase the availability and cost-attractiveness of non-alcoholic and low-alcoholic beverages, remove high alcohol drinks and cease drinking games. The intervention utilises a three-tiered accreditation framework designed to motivate intervention implementation. Football clubs in the control group will receive printed materials on topics unrelated to alcohol. Outcome data will be collected pre- and postintervention through cross-sectional telephone surveys of club members. The primary outcome measure will be alcohol consumption by club members at the club, assessed using a graduated frequency index and a seven day diary.Ethics and disseminationThe study was approved by The University of Newcastle Human Research Ethics Committee (reference: H-2008-0432). Study findings will be disseminated widely through peer-reviewed publications and conference presentations.Trial registration numberAustralian New Zealand Clinical Trials Registry: ACTRN12609000224224.
Human papillomavirus coinfection in the oral cavity of HIV-infected children
Authors: Pinheiro Raquel Santos , de França Talita Ribeiro , Rocha Barbara , Ferreira Dennis Carvalho , Ribeiro Camila Maria Beder , Cavalcanti Silvia Maria Beata , de Souza Ivete Pomarico Ribeiro , Leão Jair Carneiro , Castro Gloria Fernanda Barbosa 
Published: October 2011

AimTo identify the early presence of human papillomavirus (HPV) DNA in the oral cavity of HIV-infected children.MethodsThe study group comprised 50 HIV-infected children and 50 healthy aged paired controls. Oral mucosa samples were collected by swab, and a 450 bp HPV DNA fragment was amplified by PCR, using degenerate consensus primers directed to the L1 gene. HPV typing was performed using specifics primers for types 6/16 and 11/18.ResultsAll HPV co-infected children had vertical transmission of HIV. HPV DNA was detected in 6/50 (12.0%) of HIV children and three control group individuals 3/50 (6.0%) (p>0.01). In the HIV group, one had type 11, in the control group one had co-infection of types 11/16, and the others had type 16 and 18.ConclusionsBased upon the results, it is concluded that HPV DNA may be present in HIV disease, but no association with immunosuppression, delivery, or medical records (CD4 cell count, viral load and use of highly active antiretroviral therapy) was observed, and no differences could be observed between the groups either.