bluuebunny/crossref_metadata_2025_split huggingface dataset:
Candidates for Symbiotic Control of Sugarcane White Leaf Disease
Authors: Wangkeeree Jureemart , Miller Thomas A. , Hanboonsong Yupa 
Published: July 2012

ABSTRACT

The leafhopper
Matsumuratettix hiroglyphicus
(Matsumura) is the most important vector of a phytoplasma pathogen causing sugarcane white leaf (SCWL) disease. The purpose of this study was to evaluate candidate bacterial symbionts for possible use as vehicles in the control of the disease. 16S rRNA bacterial genes were amplified from whole bodies of
M. hiroglyphicus
leafhoppers and analyzed by cloning and sequencing. Two dominant groups were found: one belonged to the
Betaproteobacteria
that did not closely match any sequences in the database and was named bacterium associated with
M. hiroglyphicus
(BAMH). Another one found to be abundant in this leafhopper is “
Candidatus
Sulcia muelleri” in the order
Bacteroidetes
, which was previously reported in the insect members of the Auchenorrhyncha. Most
M. hiroglyphicus
leafhoppers carry both BAMH and “
Ca
. Sulcia muelleri.” Fluorescent
in situ
hybridization showed that BAMH and “
Ca
. Sulcia muelleri” colocalized in the same bacteriomes. BAMH was present in the midgut and ovaries of the leafhopper and was found in all developmental stages, including eggs, nymphs, and adults. Because BAMH appears to be specific for the SCWL vector, we evaluated it as a candidate for symbiotic control of sugarcane white leaf disease.
The Small Interfering RNA Pathway Is Not Essential for Wolbachia-Mediated Antiviral Protection in Drosophila melanogaster
Authors: Hedges Lauren M. , Yamada Ryuichi , O'Neill Scott L. , Johnson Karyn N. 
Published: July 2012

ABSTRACT

Wolbachia pipientis
delays RNA virus-induced mortality in
Drosophila
spp. We investigated whether
Wolbachia
-mediated protection was dependent on the small interfering RNA (siRNA) pathway, a key antiviral defense. Compared to
Wolbachia
-free flies, virus-induced mortality was delayed in
Wolbachia
-infected flies with loss-of-function of siRNA pathway components, indicating that
Wolbachia
-mediated protection functions in the absence of the canonical siRNA pathway.
Characterization of Osmotically Induced Filaments of Salmonella enterica
Authors: Pratt Zachary L. , Chen Bingming , Czuprynski Charles J. , Wong Amy C. L. , Kaspar Charles W. 
Published: July 2012

ABSTRACT

Salmonella enterica
forms aseptate filaments with multiple nucleoids when cultured in hyperosmotic conditions. These osmotic-induced filaments are viable and form single colonies on agar plates even though they contain multiple genomes and have the potential to divide into multiple daughter cells. Introducing filaments that are formed during osmotic stress into culture conditions without additional humectants results in the formation of septa and their division into individual cells, which could present challenges to retrospective analyses of infectious dose and risk assessments. We sought to characterize the underlying mechanisms of osmotic-induced filament formation. The concentration of proteins and chromosomal DNA in filaments and control cells was similar when standardized by biomass. Furthermore, penicillin-binding proteins in the membrane of salmonellae were active
in vitro
. The activity of penicillin-binding protein 2 was greater in filaments than in control cells, suggesting that it may have a role in osmotic-induced filament formation. Filaments contained more ATP than did control cells in standardized cell suspensions, though the levels of two F
0
F
1
-ATP synthase subunits were reduced. Furthermore, filaments could septate and divide within 8 h in 0.2× Luria-Bertani broth at 23°C, while nonfilamentous control cells did not replicate. Based upon the ability of filaments to septate and divide in this diluted broth, a method was developed to enumerate by plate count the number of individual, viable cells within a population of filaments. This method could aid in retrospective analyses of infectious dose of filamented salmonellae.
Transposon Mutagenesis of Planctomyces limnophilus and Analysis of a
pckA
Mutant
Authors: Schreier Harold J. , Dejtisakdi Wipawee , Escalante Jose Ortega , Brailo Marina 
Published: July 2012

ABSTRACT

A
Planctomyces limnophilus
mutant generated using the EZ-Tn5 transposome was found to possess an insertion within
pckA
, encoding phosphoenolpyruvate carboxykinase. Disruption of
pckA
expression and elimination of enzymatic activity resulted in poor growth in glucose-free medium, demonstrating a gluconeogenic role for
pckA
in
P. limnophilus
.
NsdC and NsdD Affect Aspergillus flavus Morphogenesis and Aflatoxin Production
Authors: Cary Jeffrey W. , Harris-Coward Pamela Y. , Ehrlich Kenneth C. , Mack Brian M. , Kale Shubha P. , Larey Christy , Calvo Ana M. 
Published: July 2012

ABSTRACTThe transcription factors NsdC and NsdD are required for sexual development inAspergillus nidulans. We now show these proteins also play a role in asexual development in the agriculturally important aflatoxin (AF)-producing fungusAspergillus flavus. We found that both NsdC and NsdD are required for production of asexual sclerotia, normal aflatoxin biosynthesis, and conidiophore development. Conidiophores innsdCandnsdDdeletion mutants had shortened stipes and altered conidial heads compared to those of wild-typeA. flavus. Our results suggest that NsdC and NsdD regulate transcription of genes required for early processes in conidiophore development preceding conidium formation. As the cultures aged, the ΔnsdCand ΔnsdDmutants produced a dark pigment that was not observed in the wild type. Gene expression data showed that although AflR is expressed at normal levels, a number of aflatoxin biosynthesis genes are expressed at reduced levels in bothnsdmutants. Expression ofaflD,aflM, andaflPwas greatly reduced innsdCmutants, and neither aflatoxin nor the proteins for these genes could be detected. Our results support previous studies showing that there is a strong association between conidiophore and sclerotium development and aflatoxin production inA. flavus.
Mitochondrial Carnitine-Dependent Acetyl Coenzyme A Transport Is Required for Normal Sexual and Asexual Development of the Ascomycete Gibberella zeae
Authors: Son Hokyoung , Min Kyunghun , Lee Jungkwan , Choi Gyung Ja , Kim Jin-Cheol , Lee Yin-Won 
Published: July 2012

ABSTRACTFungi have evolved efficient metabolic mechanisms for the exact temporal (developmental stages) and spatial (organelles) production of acetyl coenzyme A (acetyl-CoA). We previously demonstrated mechanistic roles of several acetyl-CoA synthetic enzymes, namely, ATP citrate lyase and acetyl-CoA synthetases (ACSs), in the plant-pathogenic fungusGibberella zeae. In this study, we characterized two carnitine acetyltransferases (CATs; CAT1 and CAT2) to obtain a better understanding of the metabolic processes occurring inG. zeae. We found that CAT1 functioned as an alternative source of acetyl-CoA required for lipid accumulation in anACS1deletion mutant. Moreover, deletion ofCAT1and/orCAT2resulted in various defects, including changes to vegetative growth, asexual/sexual development, trichothecene production, and virulence. Although CAT1 is associated primarily with peroxisomal CAT function, mislocalization experiments showed that the role of CAT1 in acetyl-CoA transport between the mitochondria and cytosol is important for sexual and asexual development inG. zeae. Taking these data together, we concluded thatG. zeaeCATs are responsible for facilitating the exchange of acetyl-CoA across intracellular membranes, particularly between the mitochondria and the cytosol, during various developmental stages.
Multifunctional G-Rich and RRM-Containing Domains of TbRGG2 Perform Separate yet Essential Functions in Trypanosome RNA Editing
Authors: Foda Bardees M. , Downey Kurtis M. , Fisk John C. , Read Laurie K. 
Published: July 2012

ABSTRACT

Efficient editing of
Trypanosoma brucei
mitochondrial RNAs involves the actions of multiple accessory factors.
T. brucei
RGG2 (TbRGG2) is an essential protein crucial for initiation and 3′-to-5′ progression of editing. TbRGG2 comprises an N-terminal G-rich region containing GWG and RG repeats and a C-terminal RNA recognition motif (RRM)-containing domain. Here, we perform
in vitro
and
in vivo
separation-of-function studies to interrogate the mechanism of TbRGG2 action in RNA editing. TbRGG2 preferentially binds preedited mRNA
in vitro
with high affinity attributable to its G-rich region. RNA-annealing and -melting activities are separable, carried out primarily by the G-rich and RRM domains, respectively.
In vivo
, the G-rich domain partially complements TbRGG2 knockdown, but the RRM domain is also required. Notably, TbRGG2's RNA-melting activity is dispensable for RNA editing
in vivo
. Interactions between TbRGG2 and MRB1 complex proteins are mediated by both G-rich and RRM-containing domains, depending on the binding partner. Overall, our results are consistent with a model in which the high-affinity RNA binding and RNA-annealing activities of the G-rich domain are essential for RNA editing
in vivo
. The RRM domain may have key functions involving interactions with the MRB1 complex and/or regulation of the activities of the G-rich domain.
AdeR, a PucR-Type Transcription Factor, Activates Expression of l-Alanine Dehydrogenase and Is Required for Sporulation of Bacillus subtilis
Authors: Lin Ta-Hui , Wei Guei-Tsung , Su Chien-Chen , Shaw Gwo-Chyuan 
Published: July 2012

ABSTRACTTheBacillus subtilis aldgene encodesl-alanine dehydrogenase, which catalyzes the NAD+-dependent deamination ofl-alanine to pyruvate for the generation of energy and is required for normal sporulation. The transcription ofaldis induced by alanine, but the mechanism underlying alanine induction remains unknown. Here we report that a gene (formerlyyukFand now designatedadeR) located upstream ofaldis essential for the basal and alanine-inducible expression ofald. The disruption of theadeRgene caused a sporulation defect, whereas the complementation of anadeRmutation with an intactadeRgene restored the sporulation ability.adeRexpression was not subject to autoregulation and alanine induction. Deletion and mutation analyses revealed that an inverted repeat, centered at position −74.5 relative to the transcriptional initiation site ofald, was required foraldexpression and also likely served as a ρ-independent transcription terminator. Electrophoretic mobility shift assays showed that purified His-tagged AdeR was a specific DNA-binding protein and that this inverted repeat was required for AdeR binding. AdeR shows no significant amino acid sequence similarity to the known transcriptional activators ofaldgenes from other bacteria. AdeR appears to be a member of the PucR family of transcriptional regulators. Its orthologs of unknown function are present in some otherBacillusspecies. Collectively, these findings support the notion that AdeR is a transcriptional activator which mediatesaldexpression in response to alanine availability and is important for normal sporulation inB. subtilis.
The Bacteriophage HK97 gp15 Moron Element Encodes a Novel Superinfection Exclusion Protein
Authors: Cumby Nichole , Edwards Aled M. , Davidson Alan R. , Maxwell Karen L. 
Published: July 2012

ABSTRACTA phage moron is a DNA element inserted between a pair of genes in one phage genome that are adjacent in other related phage genomes. Phage morons are commonly found within phage genomes, and in a number of cases, they have been shown to mediate phenotypic changes in the bacterial host. The temperate phage HK97 encodes a moron element, gp15, within its tail morphogenesis region that is absent in most closely related phages. We show that gp15 is actively expressed from the HK97 prophage and is responsible for providing the host cell with resistance to infection by phages HK97 and HK75, independent of repressor immunity. To identify the target(s) of this gp15-mediated resistance, we created a hybrid of HK97 and the related phage HK022. This hybrid phage revealed that the tail tube or tape measure proteins likely mediate the susceptibility of HK97 to inhibition by gp15. The N terminus of gp15 is predicted with high probability to contain a single membrane-spanning helix by several transmembrane prediction programs. Consistent with this putative membrane localization, gp15 acts to prevent the entry of phage DNA into the cytoplasm, acting in a manner reminiscent of those of several previously characterized superinfection exclusion proteins. The N terminus of gp15 and its phage homologues bear sequence similarity to YebO proteins, a family of proteins of unknown function found ubiquitously in enterobacteria. The divergence of their C termini suggests that phages have co-opted this bacterial protein and subverted its activity to their advantage.
Transcriptional Regulation of theecpOperon by EcpR, IHF, and H-NS in Attaching and Effacing Escherichia coli
Authors: Martínez-Santos Verónica I. , Medrano-López Abraham , Saldaña Zeus , Girón Jorge A. , Puente José L. 
Published: July 2012

ABSTRACTEnteropathogenic (EPEC) and enterohemorrhagic (EHEC)Escherichia coliare clinically important diarrheagenic pathogens that adhere to the intestinal epithelial surface. TheE. colicommon pili (ECP), or meningitis-associated and temperature-regulated (MAT) fimbriae, are ubiquitous among both commensal and pathogenicE. colistrains and play a role as colonization factors by promoting the interaction between bacteria and host epithelial cells and favoring interbacterial interactions in biofilm communities. The first gene of theecpoperon encodes EcpR (also known as MatA), a proposed regulatory protein containing a LuxR-like C-terminal helix-turn-helix (HTH) DNA-binding motif. In this work, we analyzed the transcriptional regulation of theecpgenes and the role of EcpR as a transcriptional regulator. EHEC and EPECecpRmutants produce less ECP, while plasmids expressing EcpR increase considerably the expression of EcpA and production of ECP. Theecpgenes are transcribed as an operon from a promoter located 121 bp upstream of the start codon ofecpR. EcpR positively regulates this promoter by binding to two TTCCT boxes distantly located upstream of theecppromoter, thus enhancing expression of downstreamecpgenes, leading to ECP production. EcpR mutants in the putative HTH DNA-binding domain are no longer able to activateecpexpression or bind to the TTCCT boxes. EcpR-mediated activation is aided by integration host factor (IHF), which is essential for counteracting the repression exerted by histone-like nucleoid-structuring protein (H-NS) on theecppromoter. This work demonstrates evidence about the interplay between a novel member of a diverse family of regulatory proteins and global regulators in the regulation of a fimbrial operon.
Hypomorphic Glycosyltransferase Alleles and Recoding at Contingency Loci Influence Glycan Microheterogeneity in the Protein Glycosylation System of Neisseria Species
Authors: Johannessen Camilla , Koomey Michael , Børud Bente 
Published: July 2012

ABSTRACTAs more bacterial protein glycosylation systems are identified and characterized, a central question that arises is, what governs the prevalence of particular glycans associated with them? In addition, accumulating evidence shows that bacterial protein glycans can be subject to the phenomenon of microheterogeneity, in which variant glycan structures are found at specific attachment sites of a given glycoprotein. Although factors underlying microheterogeneity in reconstituted expression systems have been identified and modeled, those impacting natural systems largely remain enigmatic. On the basis of a sensitive and specific glycan serotyping system, microheterogeneity has been reported for the broad-spectrum,O-linked protein glycosylation system in species within the genusNeisseria. To elucidate the mechanisms involved, a genetic approach was used to identify a hypomorphic allele ofpglA(encoding the PglA galactosyltransferase) as a significant contributor to simultaneous expression of multiple glycoforms. Moreover, this phenotype was mapped to a single amino acid polymorphism in PglA. Further analyses revealed that manypglAphase-off variants (containing out-of-frame configurations in simple nucleotide repeats within the open reading frame) were associated with disproportionally high levels of theN,N′-diacetylbacillosamine–Gal disaccharide glycoform generated by PglA. This phenotype is emblematic of nonstandard decoding involving programmed ribosomal frameshifting and/or programmed transcriptional realignment. Together, these findings provide new information regarding the mechanisms of neisserial protein glycan microheterogeneity and the anticipatory nature of contingency loci.
Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis
Authors: Guo Ming , Block Anna , Bryan Crystal D. , Becker Donald F. , Alfano James R. 
Published: July 2012

ABSTRACTThe bacterial pathogenPseudomonas syringaepv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2and are required for full virulence of DC3000 inArabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to growin planta, and its growth can be partially rescued by the expression ofkatB,katE, orkatG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protectionin planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis.
Cost-effectiveness of a community-based physical activity programme for adults (Be Active) in the UK: an economic analysis within a natural experiment
Authors: Frew Emma J , Bhatti Mobeen , Win Khine , Sitch Alice , Lyon Anna , Pallan Miranda , Adab Peymane 
Published: July 2012

ObjectiveTo determine the cost-effectiveness of a physical activity programme (Be Active) aimed at city-dwelling adults living in Birmingham, UK.MethodsVery little is known about the cost-effectiveness of public health programmes to improve city-wide physical activity rates. This paper presents a cost-effectiveness analysis that compares a physical activity intervention (Be Active) with no intervention (usual care) using an economic model to quantify the reduction in disease risk over a lifetime. Metabolic equivalent minutes achieved per week, quality-adjusted life years (QALYs) gained and healthcare costs were all included as the main outcome measures in the model. A cost-benefit analysis was also conducted using ‘willingness-to-pay’ as a measure of value.ResultsUnder base-case assumptions—that is, assuming that the benefits of increased physical activity are sustained over 5 years, participation in the Be Active programme increased quality-adjusted life expectancy by 0.06 years, at an expected discounted cost of £3552, and thus the cost-effectiveness of Be Active is £400 per QALY. When the start-up costs of the programme are removed from the economic model, the cost-effectiveness is further improved to £16 per QALY. The societal value placed on the Be Active programme was greater than the operation cost therefore the Be Active physical activity intervention results in a net benefit to society.ConclusionsParticipation in Be Active appeared to be cost-effective and cost-beneficial. These results support the use of Be Active as part of a public health programme to improve physical activity levels within the Birmingham-wide population.
Individual responses to short-term heat acclimatisation as predictors of football performance in a hot, dry environment
Authors: Racinais Sebastien , Mohr Magni , Buchheit Martin , Voss Sven Christian , Gaoua Nadia , Grantham Justin , Nybo Lars 
Published: July 2012

ObjectivesTo identify the relationship between field performance in a hot environment and individual heat acclimatisation responses in football players.MethodsNineteen semiprofessional football players completed a match in 21°C followed by 6 days of acclimatisation in dry heat (38–43°C, 12–30% relative humidity) and a match in ∼43°C. A heat-response test (30 min walk+30 min seated; 44°C) was performed at the beginning and end of the acclimatisation period.ResultsThe acclimatisation period increased sweat rate by 34% during a standard heat-exposure test and reduced sweat sodium concentration by 18% (both p≤0.005). Plasma volume changes showed large interindividual differences (−10 to +20%). Match-running performance was impaired in hot ambient condition and demonstrated marked interindividual differences (total distance −6.0±5.8%, high-intensity running −16.4±21.5%, both p≤0.002). Only haematological markers investigated during the heat-response test correlated with the ability of the player to cope with heat stress in a competitive situation; that is, changes in haematocrit between the heat-response tests were correlated to changes in total running during the game, r=−0.75; 90%CI [−0.88 to −0.51].ConclusionsHeat acclimatisation responses and in turn, match-running performance in the heat, are highly individual. The players displaying the largest haematological adaptations were able to maintain the same activity when playing in the heat as when playing in temperate conditions. As such, team doctors might use acclimatisation indicators obtained from a heat-response test to predict the ability of individual players to cope with heat in competitive situations and individualise their preparation accordingly.
When data are not missing at random: implications for measuring health conditions in the Behavioral Risk Factor Surveillance System
Authors: Frankel Martin R , Battaglia Michael P , Balluz Lina , Strine Tara 
Published: July 2012

ObjectivesTo examine the effect on estimated levels of health conditions produced from large-scale surveys, when either list-wise respondent deletion or standard demographic item-level imputation is employed. To assess the degree to which further bias reduction results from the inclusion of correlated ancillary variables in the item imputation process.DesignLarge cross-sectional (US level) household survey.Participants218 726 US adults (18 years and older) in the 2006 Behavioral Risk Factor Surveillance System Survey. This survey is the largest US telephone survey conducted by the Centers for Disease Control and Prevention.Primary and secondary outcome measuresEstimated rates of severe depression among US adults.ResultsThe use of list-wise respondent deletion and/or demographic imputation results in the underestimation of severe depression among adults in the USA. List-wise deletion produces underestimates of 9% (8.7% vs 9.5%). Demographic imputation produces underestimates of 7% (8.9% vs 9.5%). Both of these differences are significant at the 0.05 level.ConclusionThe use of list-wise deletion and/or demographic-only imputation may produce significant distortion in estimating national levels of certain health conditions.