bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transgenes for insect resistance reduce herbivory and enhance fecundity in advanced generations of crop–weed hybrids of rice
Authors: Yang Xiao , Xia Hui , Wang Wei , Wang Feng , Su Jun , Snow Allison A. , Lu Bao‐Rong 
Published: May 2011

AbstractGene flow from transgenic crops allows novel traits to spread to sexually compatible weeds. Traits such as resistance to insects may enhance the fitness of weeds, but few studies have tested for these effects under natural field conditions. We created F2 and F3 crop–weed hybrid lineages of genetically engineered rice (Oryza sativa) using lines with two transgene constructs, cowpea trypsin inhibitor (CpTI) and a Bt transgene linked to CpTI (Bt/CpTI). Experiments conducted in Fuzhou, China, demonstrated that CpTI alone did not significantly affect fecundity, although it reduced herbivory. In contrast, under certain conditions, Bt/CpTI conferred up to 79% less insect damage and 47% greater fecundity relative to nontransgenic controls, and a 44% increase in fecundity relative to the weedy parent. A small fitness cost was detected in F3 progeny with Bt/CpTI when grown under low insect pressure and direct competition with transgene‐negative controls. We conclude that Bt/CpTI transgenes may introgress into co‐occurring weedy rice populations and contribute to greater seed production when target insects are abundant. However, the net fitness benefits that are associated with Bt/CpTI could be ephemeral if insect pressure is lacking, for example, because of widespread planting of Bt cultivars that suppress target insect populations.
Live/dead real‐time polymerase chain reaction to assess new therapies against dental plaque‐related pathologies
Authors: Loozen G. , Boon N. , Pauwels M. , Quirynen M. , Teughels W. 
Published: May 2011

SummaryDNA‐based methodology for the identification and detection of specific bacteria in dental plaque offers advantages over culturing techniques. One drawback of current molecular techniques like real‐time quantitative polymerase chain reaction (RT‐QPCR) is that they are not able to distinguish between live or dead bacteria. To overcome this problem an assay was assessed to discriminate between viable or dead bacteria using DNA intercalating substances, propidium monoazide (PMA) and ethidium monoazide (EMA) in combination with RT‐QPCR. The assay was tested on oral pathogens: Streptococcus mutans, Prevotella intermedia and Aggregatibacter actinomycetemcomitans. To determine the effectiveness of EMA and PMA, different concentrations (from 5 to 100 μg ml−1) of the substances were added to viable or heat‐killed suspensions of both organisms (ranging from 108 to 104 colony‐forming units ml−1). Afterwards, PMA was tested on mixtures of varying ratios of viable and dead cells. After DNA extraction, RT‐QPCR was performed using species‐specific primers. Both compounds inhibited PCR amplification from dead cells. The EMA treatment resulted in the largest signal decrease but EMA also inhibited DNA amplification from viable cells. For this reason, PMA was selected for use in further experiments. It was shown to be efficient in allowing selective PCR detection of only viable cells in mixtures containing both viable and dead cells. The amount of amplified DNA corresponded to the percentage of viable cells in the sample. The developed assay will potentially be useful for assessing bacterial loads remaining after disinfection protocols without interference by non‐viable bacteria.
Correlation of Daptomycin Resistance in a Clinical
Staphylococcus aureus
Strain with Increased Cell Wall Teichoic Acid Production and
d
-Alanylation
Authors: Bertsche Ute , Weidenmaier Christopher , Kuehner Daniel , Yang Soo-Jin , Baur Stefanie , Wanner Stefanie , Francois Patrice , Schrenzel Jacques , Yeaman Michael R. , Bayer Arnold S. 
Published: May 2011

ABSTRACT

Cell wall thickening is a common feature among daptomycin-resistant
Staphylococcus aureus
strains. However, the mechanism(s) leading to this phenotype is unknown. We examined a number of cell wall synthesis pathway parameters in an isogenic strain set of
S. aureus
bloodstream isolates obtained from a patient with recalcitrant endocarditis who failed daptomycin therapy, including the initial daptomycin-susceptible parental strain (strain 616) and two daptomycin-resistant strains (strains 701 and 703) isolated during daptomycin therapy. Transmission electron microscopy demonstrated significantly thicker cell walls in the daptomycin-resistant strains than in the daptomycin-susceptible strain, a finding which was compatible with significant differences in dry cell weight of strain 616 versus strains 701 to 703 (
P
< 0.05). Results of detailed analysis of cell wall muropeptide composition, the degree of peptide side chain cross-linkage, and the amount of the peptidoglycan precursor, UDP-MurNAc-pentapeptide, were similar in the daptomycin-susceptible and daptomycin-resistant isolates. In contrast, the daptomycin-resistant strains contained less O-acetylated peptidoglycan. Importantly, both daptomycin-resistant strains synthesized significantly more wall teichoic acid (WTA) than the parental strain (
P
< 0.001). Moreover, the proportion of
d
-alanylated WTA species was substantially higher in the daptomycin-resistant strains than in the daptomycin-susceptible parental strain (
P
< 0.05 in comparing strain 616 versus strain 701). The latter phenotypic findings correlated with (i) enhanced
tagA
and
dltA
gene expression, respectively, and (ii) an increase in surface positive charge observed in the daptomycin-resistant versus daptomycin-susceptible isolates. Collectively, these data suggest that increases in WTA synthesis and the degree of its
d
-alanylation may play a major role in the daptomycin-resistant phenotype in some
S. aureus
strains.
A Novel Sensor Kinase Is Required for Bordetella bronchiseptica To Colonize the Lower Respiratory Tract
Authors: Kaut Callan S. , Duncan Mark D. , Kim Ji Yei , Maclaren Joshua J. , Cochran Keith T. , Julio Steven M. 
Published: May 2011

ABSTRACT

Bacterial virulence is influenced by the activity of two-component regulator systems (TCSs), which consist of membrane-bound sensor kinases that allow bacteria to sense the external environment and cytoplasmic, DNA-binding response regulator proteins that control appropriate gene expression. Respiratory pathogens of the
Bordetella
genus require the well-studied TCS BvgAS to control the expression of many genes required for colonization of the mammalian respiratory tract. Here we describe the identification of a novel gene in
Bordetella bronchiseptica
,
plrS
, the product of which shares sequence homology to several NtrY-family sensor kinases and is required for
B. bronchiseptica
to colonize and persist in the lower, but not upper, respiratory tract in rats and mice. The
plrS
gene is located immediately 5′ to and presumably cotranscribed with a gene encoding a putative response regulator, supporting the idea that PlrS and the product of the downstream gene may compose a TCS. Consistent with this hypothesis, the PlrS-dependent colonization phenotype requires a conserved histidine that serves as the site of autophosphorylation in other sensor kinases, and in strains lacking
plrS
, the production and/or cellular localization of several immune-recognized proteins is altered in comparison to that in the wild-type strain. Because
plrS
is required for colonization and persistence only in the lower respiratory tract, a site where innate and adaptive immune mechanisms actively target infectious agents, we hypothesize that its role may be to allow
Bordetella
to resist the host immune response.
Biochemical and Localization Analyses of Putative Type III Secretion Translocator Proteins CopB and CopB2 of Chlamydia trachomatis Reveal Significant Distinctions
Authors: Chellas-Géry B. , Wolf K. , Tisoncik J. , Hackstadt T. , Fields K. A. 
Published: May 2011

ABSTRACT

Chlamydia
spp. are among the many pathogenic Gram-negative bacteria that employ a type III secretion system (T3SS) to overcome host defenses and exploit available resources. Significant progress has been made in elucidating contributions of T3S to the pathogenesis of these medically important, obligate intracellular parasites, yet important questions remain. Chief among these is how secreted effector proteins traverse eukaryotic membranes to gain access to the host cytosol. Due to a complex developmental cycle, it is possible that chlamydiae utilize a different complement of proteins to accomplish translocation at different stages of development. We investigated this possibility by extending the characterization of
C. trachomatis
CopB and CopB2. CopB is detected early during infection but is depleted and not detected again until about 20 h postinfection. In contrast, CopB2 was detectible throughout development. CopB is associated with the inclusion membrane. Biochemical and ectopic expression analyses were consistent with peripheral association of CopB2 with inclusion membranes. This interaction correlated with development and required both chlamydial
de novo
protein synthesis and T3SS activity. Collectively, our data indicate that it is unlikely that CopB serves as the sole chlamydial translocation pore and that CopB2 is capable of association with the inclusion membrane.
The Hybrid Histidine Kinase Hk1 Is Part of a Two-Component System That Is Essential for Survival of Borrelia burgdorferi in Feeding Ixodes scapularis Ticks
Authors: Caimano Melissa J. , Kenedy Melisha R. , Kairu Toru , Desrosiers Daniel C. , Harman Michael , Dunham-Ems Star , Akins Darrin R. , Pal Utpal , Radolf Justin D. 
Published: May 2011

ABSTRACT

Two-component systems (TCS) are principal mechanisms by which bacteria adapt to their surroundings.
Borrelia burgdorferi
encodes only two TCS. One is comprised of a histidine kinase, Hk2, and the response regulator Rrp2. While the contribution of Hk2 remains unclear, Rrp2 is part of a regulatory pathway involving the spirochete's alternate sigma factors, RpoN and RpoS. Genes within the Rrp2/RpoN/RpoS regulon function to promote tick transmission and early infection. The other TCS consists of a hybrid histidine kinase, Hk1, and the response regulator Rrp1. Hk1 is composed of two periplasmic sensor domains (D1 and D2), followed by conserved cytoplasmic histidine kinase core, REC, and Hpt domains. In addition to its REC domain, Rrp1 contains a GGDEF motif characteristic of diguanylate cyclases. To investigate the role of Hk1 during the enzootic cycle, we inactivated this gene in two virulent backgrounds. Extensive characterization of the resulting mutants revealed a dramatic phenotype whereby Hk1-deficient spirochetes are virulent in mice and able to migrate out of the bite site during feeding but are killed within the midgut following acquisition. We hypothesize that the phosphorelay between Hk1 and Rrp1 is initiated by the binding of feeding-specific ligand(s) to Hk1 sensor domain D1 and/or D2. Once activated, Rrp1 directs the synthesis of cyclic dimeric GMP (c-di-GMP), which, in turn, modulates the expression and/or activity of gene products required for survival within feeding ticks. In contrast to the Rrp2/RpoN/RpoS pathway, which is active only within feeding nymphs, the Hk1/Rrp1 TCS is essential for survival during both larval and nymphal blood meals.
The development, feasibility and acceptability of a school-based obesity prevention programme: results from three phases of piloting
Authors: Wyatt Katrina M , Lloyd Jennifer J , Creanor Siobhan , Logan Stuart 
Published: May 2011

ObjectivesTo develop a school-based obesity prevention programme and evaluate the feasibility and acceptability of the intervention and the planned definitive cluster randomised trial.DesignThis was a three stage pilot involving six schools (398 children) in South West England, including an exploratory randomised controlled trial and qualitative interviews and focus groups with teachers, parents and children.InterventionThe Healthy Lifestyle Programme uses a range of school-based activities including lessons, assemblies, parents' evenings, interactive drama workshops and goal setting to engage schools, children and their families.ResultsOf the 398 eligible children in the three pilot phases, only four opted out and a further three withdrew from the exploratory trial. In the exploratory trial, baseline measurements (anthropometric and behavioural) were obtained for 202/204 eligible children in four schools and both 18- and 24-month outcome measurements for 193/204 and 187/204 participants, respectively. Qualitative data show that delivery of the intervention is feasible within schools and acceptable to teachers, children and families. In the exploratory trial, 18/80 children (24%) in the intervention schools and 31/122 (26%) in the control schools were overweight or obese at baseline, increasing, at 18-month follow-up, to 38/119 (32%) in the control schools compared with 18/74 (24%) in the intervention schools. At 24 months the proportion of overweight and obese children in the control schools remained at 32% (36/114), whereas the proportion in the intervention schools decreased slightly to 22% (16/73).ConclusionThe Healthy Lifestyle Programme is feasible to deliver and acceptable to schools, children and their families. We recruited, retained and obtained outcome measurements from 92% of eligible children in the exploratory trial, including measurements taken after transition to secondary school, suggesting that a definitive trial is likely to be deliverable.
Bicycle helmet wearing and the risk of head, face, and neck injury: a French case–control study based on a road trauma registry
Authors: Amoros Emmanuelle , Chiron Mireille , Martin Jean-Louis , Thélot Bertrand , Laumon Bernard 
Published: May 2011

BackgroundPrevious case–control studies on bicycle helmet efficacy are mostly Anglo-Saxon, and based on data from the early 1990s when hard-shell helmets were common.MethodsIn France, the Rhône county (1.6 million inhabitants) is covered by a road trauma registry that includes emergency department visits, hospital admissions, and fatalities. Over the 1998–2008 period, 13 797 cyclist casualties were identified. The injuries sustained were coded using the Abbreviated Injury Scale (AIS) for injuries to the head (AIS1+ and AIS3+), face (AIS1+), or neck (AIS1+). The study uses a case–control design where the control group includes cyclists injured below the neck—that is, not injured in the region associated with the helmet. We first adjusted for age, gender, and type of crash, as in a previously published Cochrane review. Then we adjusted for injury severity based on non-head, face, or neck injury, and when relevant, for crash location: type of road, urban/rural area.ResultsThe fully adjusted ORs of helmeted versus unhelmeted cyclists are: for AIS1+ head injuries, 0.69 (95% CI 0.59 to 0.81); for AIS3+ head injuries sustained in urban areas, 0.34 (95% CI 0.15 to 0.65), those sustained in rural areas, 0.07 (95% CI 0.02 to 0.23); for AIS1+ facial injuries, 0.72 (95% CI 0.62 to 0.83); and for AIS1+ neck injuries, 1.18 (95% CI 0.94 to 1.47).ConclusionThis study confirms the protective effect for head and facial injuries, even though soft-shell helmets have now become more common. The reduction of risk is greater for serious head injuries. The study is inconclusive about the risk for neck injuries.
Oral glucose tolerance testing outcomes among women at high risk for gestational diabetes mellitus
Authors: Kuti Modupe Akinrele , Abbiyesuku Fayeofori Mpakabaori , Akinlade Kehinde Simeon , Akinosun Olubayo Michael , Adedapo Kayode Solomon , Adeleye Jokotade Oluremilekun , Adesina Olubukola Adeponle 
Published: May 2011

AimsThis study aimed to determine the prevalence and relationships with known risk factors of gestational diabetes mellitus (GDM) at University College Hospital, Ibadan, Nigeria.MethodsRecords of all women referred for oral glucose tolerance testing at the metabolic research unit of the Hospital over a 2 year period were reviewed. Diagnosis of GDM was made in accordance with WHO criteria. GDM diagnosis was classified as early and late based on a gestational age <24 weeks and >24 weeks respectively. Body mass index (BMI) measurements were performed for women who presented in the first trimester. Various statistical tools including student t test and Pearson's coefficient of correlation were used.ResultsA total of 765 records were reviewed. The crude prevalence rate was 13.9%. The prevalence rate among women in the first trimester was highest at 17.4% although most of the diagnoses were made in the third trimester (55.7%). A positive family history and a family history of GDM were associated significantly with a higher fasting and 2 h post-load glucose values, irrespective of current GDM diagnosis. The most consistent associations with a diagnosis of GDM were a positive family history and a history of GDM. Age above 30 years at oral glucose testing also showed significant association. There was no BMI threshold associated with a significant risk of GDM for those women presenting in the first trimester.ConclusionsGDM is a common metabolic condition in Nigeria. Onset before the 24th week of pregnancy is not uncommon.
PTEN Is a Major Tumor Suppressor in Pancreatic Ductal Adenocarcinoma and Regulates an NF-κB–Cytokine Network
Authors: Ying Haoqiang , Elpek Kutlu G. , Vinjamoori Anant , Zimmerman Stephanie M. , Chu Gerald C. , Yan Haiyan , Fletcher-Sananikone Eliot , Zhang Hailei , Liu Yingchun , Wang Wei , Ren Xiaojia , Zheng Hongwu , Kimmelman Alec C. , Paik Ji-hye , Lim Carol , Perry Samuel R. , Jiang Shan , Malinn Brian , Protopopov Alexei , Colla Simona , Xiao Yonghong , Hezel Aram F. , Bardeesy Nabeel , Turley Shannon J. , Wang Y. Alan , Chin Lynda , Thayer Sarah P. , DePinho Ronald A. 
Published: May 2011

Abstract
Initiation of pancreatic ductal adenocarcinoma (PDAC) is driven by oncogenic KRAS mutation, and disease progression is associated with frequent loss of tumor suppressors. In this study, human PDAC genome analyses revealed frequent deletion of the PTEN gene as well as loss of expression in primary tumor specimens. A potential role for PTEN as a haploinsufficient tumor suppressor is further supported by mouse genetic studies. The mouse PDAC driven by oncogenic Kras mutation and Pten deficiency also sustains spontaneous extinction of Ink4a expression and shows prometastatic capacity. Unbiased transcriptomic analyses established that combined oncogenic Kras and Pten loss promotes marked NF-κB activation and its cytokine network, with accompanying robust stromal activation and immune cell infiltration with known tumor-promoting properties. Thus, PTEN/phosphoinositide 3-kinase (PI3K) pathway alteration is a common event in PDAC development and functions in part to strongly activate the NF-κB network, which may serve to shape the PDAC tumor microenvironment.
Significance: Detailed molecular genetics studies established that PTEN operates as a haploinsufficient tumor suppressor to promote metastatic PDAC development. The strong activation of the NF-κB–cytokine program in Pten-deficient tumors provides additional avenues for targeted therapies in tumors with altered PI3K regulation. Cancer Discovery; 1(2); 158–69. ©2011 AACR.
Read the Commentary on this article by Chiao and Ling, p. 103
This article is highlighted in the In This Issue feature, p. 91
Stromal Cell-Derived Factor-1 Retention and Cardioprotection for Ischemic Myocardium
Authors: Kanki Sachiko , Segers Vincent F.M. , Wu Weitao , Kakkar Rahul , Gannon Joseph , Sys Stanislas U. , Sandrasagra Anthony , Lee Richard T. 
Published: May 2011

Background—
Stromal cell-derived factor-1 (SDF-1) is a chemoattractant of stem/progenitor cells, and several studies have shown that SDF-1 may improve ventricular function after infarction. SDF-1 is cleaved by proteases including matrix metalloproteinase-2 (MMP-2) and CD26/dipeptidylpeptidase-4 (DPP-4), which are activated in injured tissues.

Methods and Results—
We investigated the biodistribution and functional roles of SDF-1 in experimental ischemia/reperfusion injury in rats. Radiolabeled SDF-1 given by intracoronary injection was selectively concentrated in ischemic myocardium. The enhanced uptake of SDF-1 in ischemic myocardium was not mediated by its receptor, CXCR4. Mass spectrometry and Western analyses showed that SDF-1 was cleaved by DPP-4 in plasma and myocardium, whereas a bioengineered MMP-2/DPP-4–resistant form of SDF-1, SSDF-1(S4V), was highly stable. A single dose of SSDF-1(S4V) exhibited greater potency for cardioprotection than wild-type SDF-1. SSDF-1(S4V) improved cardiac function in rats even after a 3-hour ischemic period.

Conclusions—
These results show that a single dose of protease-resistant SSDF-1(S4V) after myocardial infarction leads to dramatic improvement in angiogenesis and ventricular function even 3 hours after the onset of ischemia, revealing a simple, clinically feasible approach to prevention of heart failure.
Relationship Between Reactive Pulmonary Hypertension and Mortality in Patients With Acute Decompensated Heart Failure
Authors: Aronson Doron , Eitan Amnon , Dragu Robert , Burger Andrew J. 
Published: May 2011

Background—
In patients with heart failure, pulmonary hypertension (PH) predicts higher risk for morbidity and mortality. However, few data are available on the prognostic implications of reactive (precapillary) PH superimposed on passive (postcapillary) PH.

Methods and Results—

We performed a subgroup analysis of 242 patients with acute decompensated heart failure assigned to pulmonary artery catheter placement in the Vasodilation in the Management of Acute Congestive Heart Failure trial. Patients were classified into 3 groups, using the final (posttreatment) hemodynamic measurements: (1) no PH (mean pulmonary artery pressure ≤25 mm Hg; (2) passive PH (mean pulmonary artery pressure >25, pulmonary capillary wedge pressure >15 mm Hg, and pulmonary vascular resistance≤3 Wood units); and (3) reactive PH (mean pulmonary artery pressure >25, pulmonary capillary wedge pressure >15 mm Hg, and pulmonary vascular resistance >3 Wood units). Fifty-eight patients were classified as normal mean pulmonary artery pressure, 124 with passive PH and 60 with reactive PH. During follow-up of 6 months, 5 (8.6%), 27 (21.8%), and 29 (48.3%) deaths occurred in patients without PH, patients with passive PH, and with reactive PH, respectively (
P
<0.0001). After multivariable adjustments, reactive PH remained an independent predictor of death, with an adjusted hazard ratio of 4.8 compared with patients without PH, and 2.8 compared with patients with passive PH (95% confidence interval, 1.7 to 4.7,
P
=0.0001). Similar results were obtained when reactive PH was defined on the basis of transpulmonary gradient.

Conclusions—
Reactive PH is common among patients with acute decompensated heart failure after initial diuretic and vasodilator therapy. The adverse outcome associated with PH is predominantly due to increased mortality rates in the subgroup of patients with reactive PH.