bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complete sequence of Erwinia piriflorinigrans plasmids pEPIR37 and pEPIR5 and role of pEPIR37 in pathogen virulence
Authors: Barbé S. , Llop P. , Blom J. , Cabrefiga J. , Goesmann A. , Duffy B. , Montesinos E. , Smits T. H. M. , López M. M. 
Published: October 2012

Erwinia piriflorinigrans is a newly described pathogen causing necrosis of pear blossoms. Complete sequencing of the 37‐kb plasmid pEPIR37 common to 27 E. piriflorinigrans strains revealed homology to sequences of the ubiquitous plasmids pEA29 of the fire blight pathogen E. amylovora, plasmid pEP36 of E. pyrifoliae, plasmid pEJ30 of Erwinia sp. from Japan, and genomic regions of the related Rosaceae epiphytic Erwinia species E. tasmaniensis and E. billingiae. A second 5·5‐kb cryptic plasmid pEPIR5, found in 12 E. piriflorinigrans strains, was also sequenced revealing mobilization and replication proteins with similarities to many small ColE1‐type plasmids in Erwinia spp. and other enterobacteria. Functional analyses of pEPIR37 introduced into a strain of E. amylovora cured of pEA29 plasmid, which has a reduced virulence, showed a role in increasing symptom development similar to that observed in E. amylovora carrying plasmid pEA29.
Coxiella burnetii Shedding During the Peripartum Period and Subsequent Fertility in Dairy Cattle
Authors: Garcia‐Ispierto I , López‐Helguera I , Tutusaus J , Serrano B , Monleón E , Badiola JJ , López‐Gatius F 
Published: October 2012

ContentsThe objective of this study was to assess the effects of Coxiella burnetii shedding or seropositivity on post‐partum recovery and subsequent fertility in high‐producing dairy cows. Given the difficulty in diagnosing C. burnetii infection at the farm level, an exhaustive series of tests in 43 pregnant animals that delivered at least one live calf were conducted, including blood serology and PCR of milk or colostrum, cotyledons (only at parturition), faeces, vaginal fluid against C. burnetii on gestation Day 171–177, at parturition and on Days 1–7, 8–14, 15–21, 22–28, 29–35 and 90–97 post‐partum. During scheduled herd visits, ultrasonography (US) of the genital tract and examination of vaginal fluid were performed on Days 15–21 (V1), 22–28 (V2), 29–35 (V3) and 51–57 (V4) post‐partum by the same veterinarian. Logistic regression analysis revealed that the likelihood of suffering endometritis (the presence of echogenic intrauterine fluid (IUF), cervical diameter of ≥4 cm or endometrial thickness ≥0.75 cm) was lower in C. burnetii‐seropositive animals (OR = 0.10), compared with C. burnetii‐seronegative animals. According to Kaplan–Meier survival analysis, C. burnetii‐seronegative and non‐shedding cows showed a delayed return to luteal activity and conception was delayed in non‐shedding animals, compared with the remaining animals. Overall, the results of our study provide useful insight into the effects of C. burnetii infection on post‐partum recovery and subsequent fertility. In particular, animals not infected with Coxiella seem to be susceptible to infection and not protected against the bacterium in dairy herds. The elevated costs of determining an infection at the farm level, make monitoring of cows virtually impossible from a clinical point of view.
Intrauterine Idiopathic Amputation of the Head of a Porcine Foetus
Authors: Agerholm JS , Garoussi MT 
Published: October 2012

ContentsAn anencephalic full‐term porcine foetus accompanied by a mummified head was submitted for examination. The neck almost entirely lacked skin and was covered by granulation tissue as were the exposed parts of the spine and spinal cord. The case represents a rare case of intrauterine amputation. A definitive cause could not be established because the placenta was not available. The most likely cause is strangulation of the neck. Such strangulation could be due to a defect of the allantoamnion with herniation of the foetal head or entanglement by amniotic constriction bands.
Is Vitamin C Intake too Low in Dialysis Patients?
Authors: Raimann Jochen G. , Levin Nathan W. , Craig Ronald G. , Sirover William , Kotanko Peter , Handelman Garry 
Published: October 2012

AbstractVitamin C has several well‐established roles in physiology including synthesis of collagen, carnitine and epinephrine, absorption of dietary iron, and mobilization of storage iron for erythropoeisis. Loss of several of these functions explains the pathology of scurvy, where defective collagen synthesis and anemia are major symptoms. Vitamin C deficiency is very common in dialysis patients and may arise from dialytic vitamin C clearance, restricted intake of vitamin C‐rich foods, and increased vitamin C catabolism in vivo from inflammation. In the dialysis population, greater vitamin C intake may be needed for optimal health. Relationships between intake, body distribution, inflammation, and dialytic losses are complex and need further study. Concern about vitamin C metabolism leading to accumulation of tissue oxalate has led to the recommendation that vitamin C intake equals, but not exceeds, the intake recommended for the general population. Vitamin C deficiency in dialysis patients may have clinical consequences; a study in Renal Research Institute clinics found an association with periodontal disease. Data also support a role for vitamin C in prevention of dialysis‐related anemia. New research questions are proposed in this editorial, with a discussion of strategies to determine the optimal provision of vitamin C for CKD patients.
Endothelial dysfunction in gestational hypertension induced by catechol‐O‐methyltransferase inhibition
Authors: Hernandez M. , Hernandez I. , Rodriguez F. , Pertegal M. , Bonacasa B. , Salom M. G. , Quesada T. , Fenoy F. J. 
Published: October 2012

New Findings
What is the central question of this study?Gestational hypertension is a major obstetric problem of placental origin, associated with reduced production of 2‐methoxyestradiol. In this study, we evaluated in rats the consequences of pharmacological inhibition of catechol‐O‐methyltransferase, the enzyme that produces 2‐methoxyestradiol from 2‐hydroxyestradiol.
What is the main finding and its importance?The present study provides evidence that inhibition of catechol‐O‐methyltransferase in pregnant rats produces arterial hypertension and endothelial dysfunction due to reduced nitric oxide bioavailability. The results help us to understand gestational hypertension and support a possible new approach to early diagnosis and treatment of the disease.
The present study evaluated whether catechol‐O‐methyltransferase inhibition in pregnant rats results in increased blood pressure and vascular endothelial dysfunction as a consequence of decreased nitric oxide bioavailability. Pregnant Sprague–Dawley rats were given entacapone (a catechol‐O‐methyltransferase inhibitor) by gavage from the 10th to the 20th day of pregnancy. Blood pressure was measured by plethysmography in the tail artery. Vascular endothelial function and NO release were assessed both in the absence and in the presence of tempol. Systolic blood pressure increased significantly in pregnant rats treated with entacapone compared with untreated pregnant rats on days 14 (143 ± 4 versus 122 ± 3 mmHg) and 19 of gestation (129 ± 4 versus 115 ± 5 mmHg). Both conductance (aortic rings) and resistance vessels (mesenteric small arterial vessels) from entacapone‐treated pregnant rats showed diminished relaxation in response to acetylcholine compared with vessels from vehicle‐treated pregnant and virgin rats. In mesenteric arterioles, this endothelial dysfunction was abolished in the presence of l‐NAME, indicating that it was caused by reduced NO availability, and it also improved in the presence of tempol, suggesting increased oxidative stress in hypertensive pregnant rats. Endothelial release of nitric oxide induced by calcium ionophore (A23187) was significantly greater in aortas from vehicle‐treated pregnant rats than in aortas from pregnant rats given entacapone. This endothelial dysfunction seen in hypertensive rats was prevented by addition of tempol. The present study provides evidence that catechol‐O‐methyltransferase inhibition in pregnant rats produces arterial hypertension and endothelial dysfunction due to reduced nitric oxide bioavailability.
MprAB Regulates theespAOperon in Mycobacterium tuberculosis and Modulates ESX-1 Function and Host Cytokine Response
Authors: Pang Xiuhua , Samten Buka , Cao Guangxiang , Wang Xisheng , Tvinnereim Amy R. , Chen Xiu-Lan , Howard Susan T. 
Published: October 2012

ABSTRACTThe ESX-1 secretion system exports the immunomodulatory protein ESAT-6 and other proteins important in the pathogenesis ofMycobacterium tuberculosis. Components and substrates of ESX-1 are encoded at several loci, but the regulation of the encoding genes is only partially understood. In this study, we investigated the role of the MprAB two-component system in the regulation of ESX-1 activity. We determined that MprAB directly regulates theespAgene cluster, a locus necessary for ESX-1 function. Transcript mapping determined that the five genes in the cluster form an operon with two transcriptional start points, and several MprA binding sites were detected in theespApromoter. Expression analyses and promoter constructs indicated that MprAB represses theespAoperon. However, the MprAB mutant Rv-D981 secreted lower levels of EspA, ESAT-6, and the ESX-1 substrate EspB than control strains. Secretion of CFP10, which is normally cosecreted with ESAT-6, was similar in Rv-D981 and control strains, further demonstrating aberrant ESX-1 activity in the mutant. ESAT-6 induces proinflammatory cytokines, and macrophages infected with Rv-D981 elicited lower levels of interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α), consistent with the reduced levels of ESAT-6. These findings indicate that MprAB modulates ESX-1 function and reveal a new role for MprAB in host-pathogen interactions.
Solution Structure of Escherichia coli FeoA and Its Potential Role in Bacterial Ferrous Iron Transport
Authors: Lau Cheryl K. Y. , Ishida Hiroaki , Liu Zhihong , Vogel Hans J. 
Published: October 2012

ABSTRACT

Iron is an indispensable nutrient for most organisms. Ferric iron (Fe
3+
) predominates under aerobic conditions, while during oxygen limitation ferrous (Fe
2+
) iron is usually present. The Feo system is a bacterial ferrous iron transport system first discovered in
Escherichia coli
K-12. It consists of three genes,
feoA
,
feoB
, and
feoC
(
yhgG
). FeoB is thought to be the main transmembrane transporter while FeoC is considered to be a transcriptional regulator. Using multidimensional nuclear magnetic resonance (NMR) spectroscopy, we have determined the solution structure of
E. coli
FeoA. The structure of FeoA reveals a Src-homology 3 (SH3)-like fold. The structure is composed of a β-barrel with two α-helices where one helix is positioned over the barrel. In comparison to the standard eukaryotic SH3 fold, FeoA has two additional α-helices. FeoA was further characterized by heteronuclear NMR dynamics measurements, which suggest that it is a monomeric, stable globular protein. Model-free analysis of the NMR relaxation results indicates that a slow conformational dynamic process is occurring in β-strand 4 that may be important for function.
31
P NMR-based GTPase activity measurements with the N-terminal domain of FeoB (NFeoB) indicate a higher GTP hydrolysis rate in the presence of potassium than with sodium. Further enzymatic assays with NFeoB suggest that FeoA may not act as a GTPase-activating protein as previously proposed. These findings, together with bioinformatics and structural analyses, suggest that FeoA may have a different role, possibly interacting with the cytoplasmic domain of the highly conserved core portion of the FeoB transmembrane region.
Antibacterial Activity of Alkyl Gallates against Xanthomonas citri subsp.
citri
Authors: Silva I. C. , Regasini L. O. , Petrônio M. S. , Silva D. H. S. , Bolzani V. S. , Belasque J. , Sacramento L. V. S. , Ferreira H. 
Published: October 2012

ABSTRACT

The plant-pathogenic bacterium
Xanthomonas citri
subsp.
citri
is the causal agent of Asiatic citrus canker, a serious disease that affects all the cultivars of citrus in subtropical citrus-producing areas worldwide. There is no curative treatment for citrus canker; thus, the eradication of infected plants constitutes the only effective control of the spread of
X. citri
subsp.
citri
. Since the eradication program in the state of São Paulo, Brazil, is under threat, there is a clear risk of
X. citri
subsp.
citri
becoming endemic in the main orange-producing area in the world. Here we evaluated the potential use of alkyl gallates to prevent
X. citri
subsp.
citri
growth. These esters displayed a potent anti-
X. citri
subsp.
citri
activity similar to that of kanamycin (positive control), as evaluated by the resazurin microtiter assay (REMA). The treatment of
X. citri
subsp.
citri
cells with these compounds induced altered cell morphology, and investigations of the possible intracellular targets using
X. citri
subsp.
citri
strains labeled for the septum and centromere pointed to a common target involved in chromosome segregation and cell division. Finally, the artificial inoculation of citrus with
X. citri
subsp.
citri
cells pretreated with alkyl gallates showed that the bacterium loses the ability to colonize its host, which indicates the potential of these esters to protect citrus plants against
X. citri
subsp.
citri
infection.
Characterization of the Effects of an
rpoC
Mutation That Confers Resistance to the Fst Peptide Toxin-Antitoxin System Toxin
Authors: Brinkman Cassandra L. , Bumgarner Roger , Kittichotirat Weerayuth , Dunman Paul M. , Kuechenmeister Lisa J. , Weaver Keith E. 
Published: October 2012

ABSTRACT

Overexpression of the Fst toxin in
Enterococcus faecalis
strain OG1X leads to defects in chromosome segregation, cell division and, eventually, membrane integrity. The M7 mutant derivative of OG1X is resistant to most of these effects but shows a slight growth defect in the absence of Fst. Full-genome sequencing revealed two differences between M7 and its OG1X parent. First, OG1X contains a frameshift mutation that inactivates the
etaR
response regulator gene, while M7 is a wild-type revertant for
etaR
. Second, the M7 mutant contains a missense mutation in the
rpoC
gene, which encodes the β′ subunit of RNA polymerase. Mutagenesis experiments revealed that the
rpoC
mutation was primarily responsible for the resistance phenotype. Microarray analysis revealed that a number of transporters were induced in OG1X when Fst was overexpressed. These transporters were not induced in M7 in response to Fst, and further experiments indicated that this had a direct protective effect on the mutant cells. Therefore, exposure of cells to Fst appears to have a cascading effect, first causing membrane stress and then potentiation of these effects by overexpression of certain transporters.
Glycopeptide Sulfation Evades Resistance
Authors: Kalan Lindsay , Perry Julie , Koteva Kalinka , Thaker Maulik , Wright Gerard 
Published: October 2012

ABSTRACT

The incidence of antibiotic resistance among pathogenic microorganisms is increasing at an alarming rate. Resistance against front-line therapeutics such as the glycopeptide antibiotic vancomycin has emerged and has spread to highly virulent pathogens, including
Staphylococcus aureus
. Glycopeptide antibiotics are natural products from the
Actinomycetes
that have a characteristic heptapeptide core. The chemical diversity of the class is achieved through glycosylation, halogenation, methylation, and acylation of the core, modifications that are implicated in improved solubility, stability, or activity of the molecule. Sulfation is yet another modification observed infrequently in glycopeptides, but its role is not known. Although glycopeptide sulfotransferases are found in the environmental metagenome and must therefore serve an evolutionary purpose, all previous studies have reported decreased antibiotic activity with sulfation. We report that sulfation of glycopeptides has little effect on the compound's ability to bind its target, the
d
-Ala-
d
-Ala peptidoglycan precursors of the bacterial cell wall. However, sulfation does impact glycopeptide dimerization, and importantly, sulfated glycopeptides are significantly less potent inducers of the resistance gene cluster
vanHAX
in actinomycetes. Our results begin to unravel the mystery of the biological role of glycopeptide sulfation and offer a potential new strategy for the development of new antibiotics that avoid resistance.
Characterization of the Functional Domains of the SloR Metalloregulatory Protein in Streptococcus mutans
Authors: Haswell Jeffrey R. , Pruitt Benjamin W. , Cornacchione Louis P. , Coe Christopher L. , Smith Evan G. , Spatafora Grace A. 
Published: October 2012

ABSTRACT

Streptococcus mutans
is a commensal member of the healthy plaque biofilm and the primary causative agent of dental caries. The present study is an investigation of SloR, a 25-kDa metalloregulatory protein that modulates genes responsible for
S. mutans
-induced cariogenesis. Previous studies of SloR homologues in other bacterial pathogens have identified three domains critical to repressor functionality: an N-terminal DNA-binding domain, a central dimerization domain, and a C-terminal FeoA (previously SH3-like) domain. We used site-directed mutagenesis to identify critical amino acid residues within each of these domains of the SloR protein. Select residues were targeted for mutagenesis, and nonconservative amino acid substitutions were introduced by overlap extension PCR. Furthermore, three C-terminally truncated SloR variants were generated using conventional PCR. The repressor functionality and DNA-binding ability of each variant was assessed using CAT reporter gene assays, real-time semiquantitative reverse transcriptase (qRT)-PCR, and electrophoretic mobility shift assays. We identified 12 residues within SloR that cause significant derepression of
sloABC
promoter activity (
P
< 0.05) compared to the results for wild-type SloR. Derepression was particularly noteworthy in metal ion-binding site 1 mutants, consistent with the site's importance in gene repression by SloR. In addition, a hyperactive SloR(E169A/Q170A) mutant was identified as having significantly heightened repression of
sloABC
promoter activity, and experiments with C-terminal deletion mutants support involvement of the FeoA domain in SloR-mediated gene repression. Given these results, we describe the functional domains of the
S. mutans
SloR protein and propose that the hyperactive mutant could serve as a target for rational drug design aimed at repressing SloR-mediated virulence gene expression.
Perthes’ disease of the hip: socioeconomic inequalities and the urban environment
Authors: Perry Daniel C , Bruce Colin E , Pope Daniel , Dangerfield Peter , Platt Mary Jane , Hall Andrew J 
Published: October 2012

IntroductionPerthes’ disease is a puzzling childhood hip disorder for which the aetiology is unknown. It is known to be associated with socioeconomic deprivation. Urban environments have also been implicated as a risk factor, however socioeconomic deprivation often occurs within urban environments and it is unclear if this association is the result of confounding. The objective of the current work was to gain a greater understanding of the influence of the urban/rural environment in Perthes’ disease.MethodsThis was a descriptive observational study using the Scottish Morbidity Record, based in Scotland, UK using data from 2000–2010. A total of 443 patients with a discharge diagnosis of Perthes’ disease were included. Socioeconomic deprivation was determined using the Scottish Index of Multiple Deprivation, and exposure to the ‘urban environment’ was recorded based on the Scottish Urban–Rural Classification.ResultsThere was a strong association with socioeconomic deprivation, with rates among the most deprived quintile more than twice those of the most affluent (RR 2.1 (95% CI 1.5 to 2.9)). Urban areas had a greater rate of Perthes’ disease discharges (RR 1.8 (95% CI 1.1 to 3.2)), though this was a reflection of greater deprivation in urban areas. Stratification for socioeconomic deprivation revealed similar discharge rates in urban and rural environments, suggesting that the aetiological determinants were not independently associated with urban environments.ConclusionsThe occurrence of Perthes’ disease within urban environments is high, yet this appears to be a reflection of higher socioeconomic deprivation exposure. Disease rates appear equivalent in similarly deprived urban and non-urban areas, suggesting that the determinant is not a consequence of the urban environment.
Adverse events related to intravenous antibiotic therapy: a prospective observational study in the treatment of infective endocarditis
Authors: De Paula Débora Holanda Gonçalves , Tura Bernardo Rangel , Lamas Cristiane da Cruz 
Published: October 2012

ObjectiveThe goal of this prospective observational study was to identify adverse events (AEs) related to the use of intravenous access sites used for infective endocarditis (IE) treatment in a tertiary care hospital.DesignThis is an observational, analytical and prospective study on AEs resulting from the use of intravenous access sites in patients under antimicrobial treatment for IE. Patients enrolled in the International Collaboration on Endocarditis (ICE) study had their peripheral, short-term central catheters (CVC) and peripherally inserted central catheters (PICC) monitored for AEs.SettingTertiary care hospital for cardiac surgery in Rio de Janeiro, Brazil.PatientsPatients over 14 years of age, hospitalised in 2009 and 2010 with possible or definite criteria for IE by the modified Duke criteria were included.Main outcome measuresAEs related to intravenous catheters: erythema and infiltration, fever, obstruction, externalisation and blood stream infection.ResultsThirty-seven episodes of IE in 35 patients were studied. Mean patient age was 44.32±15.2 years; 22 (63%) were men. The number of vascular catheters studied were 253, 148 of which were peripheral, 85 CVC (21 of which for haemodialysis) and 20 PICC. The most frequent AEs were ‘erythema’ and ‘infiltration’ for peripheral catheters, ‘fever’ for CVCs and ‘obstruction’ and ‘externalisation’ for PICCs. The number of catheter-days was 360 for peripheral catheters, 1.156 for CVC and 420 for PICC. Kaplan-Meier curves for CVC and PICC showed statistical difference for obstruction (p<0.001) in PICCs. More bacteraemia occurred in CVC compared with PICC.ConclusionsThe choice of intravenous access sites is critical in the treatment of IE. Close observation for AEs and stricter implementation of infection control measures and better manipulation of catheters are suggested.