bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Inoculation of Male Rats with Coxiella burnetii: Successful Infection but No Transmission to Cage Mates
Authors: Opsteegh Marieke , Hogerwerf Lenny , Nooijen Stephane , Dam-Deisz Cecile , de Heer Lianne , Reusken Chantal , Bouma Annemarie , Roest Hendrik-Jan , Nielen Mirjam , van der Giessen Joke 
Published: June 2012

ABSTRACT

Beginning in 2007, the largest human Q fever outbreak ever described occurred in the Netherlands. Dairy goats from intensive farms were identified as the source, amplifying
Coxiella burnetii
during gestation and shedding large quantities during abortions. It has been postulated that wild rodents are reservoir hosts from which
C. burnetii
can be transmitted to domestic animals and humans. However, little is known about the infection dynamics of
C. burnetii
in wild rodents. The aim of this study was to investigate whether brown rats (
Rattus norvegicus
) can be experimentally infected with
C. burnetii
and whether transmission to a cage mates occurs. Fourteen male brown rats (wild type) were intratracheally or intranasally inoculated with a Dutch
C. burnetii
isolate obtained from a goat. At 3 days postinoculation, a contact rat was placed with each inoculated rat. The pairs were monitored using blood samples and rectal and throat swabs for 8 weeks, and after euthanasia the spleens were collected. Rats became infected by both inoculation routes, and detection of
C. burnetii
DNA in swabs suggests that excretion occurred. However, based on the negative spleens in PCR and the lack of seroconversion, none of the contact animals was considered infected; thus, no transmission was observed. The reproduction ratio
R
0
was estimated to be 0 (95% confidence interval = 0 to 0.6), indicating that it is unlikely that rats act as reservoir host of
C. burnetii
through sustained transmission between male rats. Future research should focus on other transmission routes, such as vertical transmission or bacterial shedding during parturition.
Capturing Greater 16S rRNA Gene Sequence Diversity within the Domain Bacteria
Authors: Winsley T. , van Dorst J. M. , Brown M. V. , Ferrari B. C. 
Published: June 2012

ABSTRACT

A large proportion of “universal” 16S PCR primers lack sequence homology to many of the “candidate” divisions, severely limiting bacterial diversity assessments. We designed a primer set that offers a 50% increase
in silico
in coverage of the domain
Bacteria
over the commonly used primer combination 27F/519R. Comparisons using pyrosequencing on soil environments showed a significant increase in recovery of taxonomic diversity with around a 3-fold increase in recovery of sequences from candidate divisions.
Antifungal Activity of Bacillus amyloliquefaciens NJN-6 Volatile Compounds against Fusarium oxysporum f. sp. cubense
Authors: Yuan Jun , Raza Waseem , Shen Qirong , Huang Qiwei 
Published: June 2012

ABSTRACT

Bacillus amyloliquefaciens
NJN-6 produces volatile compounds (VOCs) that inhibit the growth and spore germination of
Fusarium oxysporum
f. sp.
cubense
. Among the total of 36 volatile compounds detected, 11 compounds completely inhibited fungal growth. The antifungal activity of these compounds suggested that VOCs can play important roles over short and long distances in the suppression of
Fusarium oxysporum
.
Phenylacetic Acid Catabolism and Its Transcriptional Regulation in Corynebacterium glutamicum
Authors: Chen Xi , Kohl Thomas A. , Rückert Christian , Rodionov Dmitry A. , Li Ling-Hao , Ding Jiu-Yuan , Kalinowski Jörn , Liu Shuang-Jiang 
Published: June 2012

ABSTRACT

The industrially important organism
Corynebacterium glutamicum
has been characterized in recent years for its robust ability to assimilate aromatic compounds. In this study,
C. glutamicum
strain AS 1.542 was investigated for its ability to catabolize phenylacetic acid (PAA). The
paa
genes were identified; they are organized as a continuous
paa
gene cluster. The type strain of
C. glutamicum
, ATCC 13032, is not able to catabolize PAA, but the recombinant strain ATCC 13032/pEC-K18
mob
2::
paa
gained the ability to grow on PAA. The
paaR
gene, encoding a TetR family transcription regulator, was studied in detail. Disruption of
paaR
in strain AS 1.542 resulted in transcriptional increases of all
paa
genes. Transcription start sites and putative promoter regions were determined. An imperfect palindromic motif (5′-ACTNACCGNNCGNNCGGTNAGT-3′; 22 bp) was identified in the upstream regions of
paa
genes. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of PaaR to this motif, and phenylacetyl coenzyme A (PA-CoA) blocked binding. It was concluded that PaaR is the negative regulator of PAA degradation and that PA-CoA is the PaaR effector. In addition, GlxR binding sites were found, and binding to GlxR was confirmed. Therefore, PAA catabolism in
C. glutamicum
is regulated by the pathway-specific repressor PaaR, and also likely by the global transcription regulator GlxR. By comparative genomic analysis, we reconstructed orthologous PaaR regulons in 57 species, including species of
Actinobacteria
,
Proteobacteria
, and
Flavobacteria
, that carry PAA utilization genes and operate by conserved binding motifs, suggesting that PaaR-like regulation might commonly exist in these bacteria.
Application of
pheB
as a Reporter Gene for Geobacillus spp., Enabling Qualitative Colony Screening and Quantitative Analysis of Promoter Strength
Authors: Bartosiak-Jentys Jeremy , Eley Kirstin , Leak David J. 
Published: June 2012

ABSTRACT

The
pheB
gene from
Geobacillus stearothermophilus
DSM6285 has been exploited as a reporter gene for
Geobacillus
spp. The gene product, catechol 2,3-dioxygenase (C23O), catalyzes the formation of 2-hydroxymuconic semialdehyde, which can be readily assayed. The reporter was used to examine expression from the
ldh
promoter associated with fermentative metabolism.
Effect of
iacP
Mutation on Flagellar Phase Variation in Salmonella enterica Serovar Typhimurium Strain UK-1
Authors: Eom Jeong Seon , Kim Jin Seok , Jang Jung Im , Kim Hyeon Guk , Bang Iel-Soo , Park Yong Keun 
Published: June 2012

ABSTRACT

Flagella are surface appendages that are important for bacterial motility and invasion of host cells. Two flagellin subunits in
Salmonella enterica
serovar Typhimurium, FliC and FljB, are alternatively expressed by a site-specific DNA inversion mechanism called flagellar phase variation. Although this inversion mechanism is understood at the molecular level, the key factor controlling the expression of the two flagellin subunits has not been determined. In this study, we found that a putative acyl carrier protein, IacP, affects flagellar phase variation in
S.
Typhimurium strain UK-1 under
Salmonella
pathogenicity island 1 (SPI1)-inducing conditions. Liquid chromatography-mass spectrometry analysis of the secreted proteins from
S.
Typhimurium determined that the amount of FljB secreted was significantly higher in the
iacP
mutant strain, a finding confirmed by Western blot analysis. Northern blotting, quantitative PCR, and microarray data showed that the level of FljB in the
iacP
mutant strain was regulated at the transcriptional level, although the transcription and expression of the
fliC
gene were independent of IacP. FljB production was abolished by the deletion of the Hin DNA invertase but could be restored by the introduction of a plasmid carrying the
hin
gene. We also found that in the
iacP
mutant strain, the orientation of the invertible H segment is in the FljB-expressing phase. Furthermore, electron microscopy observations indicated that the
iacP
mutant strain had more flagella per cell than the wild-type strain. These results suggest that IacP is associated with flagellar phase switching under SPI1-inducing conditions.
First Insights into the Unexplored Two-Component System YehU/YehT in Escherichia coli
Authors: Kraxenberger Tobias , Fried Luitpold , Behr Stefan , Jung Kirsten 
Published: June 2012

ABSTRACT

Two-component systems (TCSs) consisting of a membrane-anchored histidine kinase (HK) and a response regulator (RR) with DNA-binding activity. are major players in signal transduction in prokaryotes. Whereas most TCSs in
Escherichia coli
are well characterized, almost nothing is known about the LytS-like HK YehU and the corresponding LytTR-like RR YehT. To identify YehT-regulated genes, we compared the transcriptomes of
E. coli
cells overproducing either YehT or the RR KdpE (control). The expression levels of 32 genes differed more than 8-fold between the two strains. A comprehensive evaluation of these genes identified
yjiY
as a target of YehT. Electrophoretic mobility shift assays with purified YehT confirmed that YehT interacts directly with the
yjiY
promoter. Specifically, YehT binds to two direct repeats of the motif ACC(G/A)CT(C/T)A separated by a 13-bp spacer in the
yjiY
promoter. The target gene
yjiY
encodes an inner membrane protein belonging to the CstA superfamily of transporters. In
E. coli
cells growing in media containing peptides or amino acids as a carbon source,
yjiY
is strongly induced at the onset of the stationary-growth phase. Moreover, expression was found to be dependent on cyclic AMP (cAMP)/cAMP receptor protein (CRP). It is suggested that YehU/YehT participates in the stationary-phase control network.
Transcription of the
oprF
Gene of Pseudomonas aeruginosa Is Dependent Mainly on the SigX Sigma Factor and Is Sucrose Induced
Authors: Bouffartigues Emeline , Gicquel Gwendoline , Bazire Alexis , Bains Manjeet , Maillot Olivier , Vieillard Julien , Feuilloley Marc G. J. , Orange Nicole , Hancock R. E. W. , Dufour Alain , Chevalier Sylvie 
Published: June 2012

ABSTRACT

The OprF porin is the major outer membrane protein of
Pseudomonas aeruginosa
. OprF is involved in several crucial functions, including cell structure, outer membrane permeability, environmental sensing, and virulence. The
oprF
gene is preceded by the
sigX
gene, which encodes the poorly studied extracytoplasmic function (ECF) sigma factor SigX. Three
oprF
promoters were previously identified. Two intertwined promoters dependent on σ
70
and SigX are located in the
sigX
-
oprF
intergenic region, whereas a promoter dependent on the ECF AlgU lies within the
sigX
gene. An additional promoter was found in the
cmpX
-
sigX
intergenic region. In this study, we dissected the contribution of each promoter region and of each sigma factor to
oprF
transcription using transcriptional fusions. In Luria-Bertani (LB) medium, the
oprF
-proximal region (
sigX
-
oprF
intergenic region) accounted for about 80% of the
oprF
transcription, whereas the AlgU-dependent promoter had marginal activity. Using the
sigX
mutant PAOSX, we observed that the SigX-dependent promoter was largely predominant over the σ
70
-dependent promoter.
oprF
transcription was increased in response to low NaCl or high sucrose concentrations, and this induced transcription was strongly impaired in the absence of SigX. The lack of OprF itself increased
oprF
transcription. Since these conditions led to cell wall alterations,
oprF
transcription could be activated by signals triggered by perturbation of the cell envelope.
Rot and SaeRS Cooperate To Activate Expression of the Staphylococcal Superantigen-Like Exoproteins
Authors: Benson Meredith A. , Lilo Sarit , Nygaard Tyler , Voyich Jovanka M. , Torres Victor J. 
Published: June 2012

ABSTRACT

Staphylococcus aureus
is a significant human pathogen that is capable of infecting a wide range of host tissues. This bacterium is able to evade the host immune response by utilizing a repertoire of virulence factors. These factors are tightly regulated by various two-component systems (TCS) and transcription factors. Previous studies have suggested that transcriptional regulation of a subset of immunomodulators, known as the staphylococcal superantigen-like proteins (Ssls), is mediated by the master regulators accessory gene regulator (Agr) TCS,
S. aureus
exoprotein expression (Sae) TCS, and Rot. Here we demonstrate that Rot and SaeR, the response regulator of the Sae TCS, synergize to coordinate the activation of the
ssl
promoters. We have determined that both transcription factors are required, but that neither is sufficient, for promoter activation. This regulatory scheme is mediated by direct binding of both transcription factors to the
ssl
promoters. We also demonstrate that clinically relevant methicillin-resistant
S. aureus
(MRSA) strains respond to neutrophils via the Sae TCS to upregulate the expression of
ssl
s. Until now, Rot and the Sae TCS have been proposed to work in opposition of one another on their target genes. This is the first example of these two regulators working in concert to activate promoters.
Cysteine Catabolism and Cysteine Desulfhydrase (CdsH/STM0458) in Salmonella enterica Serovar Typhimurium
Authors: Oguri Tamiko , Schneider Barbara , Reitzer Larry 
Published: June 2012

ABSTRACT

Cysteine is potentially toxic and can affect diverse functions such as oxidative stress, antibiotic resistance, and swarming motility. The contribution of cysteine catabolism in modulating responses to cysteine has not been examined, in part because the genes have not been identified and mutants lacking these genes have not been isolated or characterized. We identified the gene for a previously described cysteine desulfhydrase, which we designated
cdsH
(formerly STM0458). We also identified a divergently transcribed gene that regulates
cdsH
expression, which we designated
cutR
(formerly
ybaO
, or STM0459). CdsH appears to be the major cysteine-degrading and sulfide-producing enzyme aerobically but not anaerobically. Mutants with deletions of
cdsH
and
ybaO
exhibited increased sensitivity to cysteine toxicity and altered swarming motility but unaltered cysteine-enhanced antibiotic resistance and survival in macrophages.
Increased Production of the Exopolysaccharide Succinoglycan Enhances Sinorhizobium meliloti 1021 Symbiosis with the Host Plant Medicago truncatula
Authors: Jones Kathryn M. 
Published: June 2012

ABSTRACT

The nitrogen-fixing rhizobial symbiont
Sinorhizobium meliloti
1021 produces acidic symbiotic exopolysaccharides that enable it to initiate and maintain infection thread formation on host legume plants. The exopolysaccharide that is most efficient in mediating this process is succinoglycan (exopolysaccharide I [EPSI]), a polysaccharide composed of octasaccharide repeating units of 1 galactose and 7 glucose residues, modified with succinyl, acetyl, and pyruvyl substituents. Previous studies had shown that
S. meliloti
1021 mutants that produce increased levels of succinoglycan, such as
exoR
mutants, are defective in symbiosis with host plants, leading to the hypothesis that high levels of succinoglycan production might be detrimental to symbiotic development. This study demonstrates that increased succinoglycan production itself is not detrimental to symbiotic development and, in fact, enhances the symbiotic productivity of
S. meliloti
1021 with the host plant
Medicago truncatula
cv. Jemalong A17. Increased succinoglycan production was engineered by overexpression of the
exoY
gene, which encodes the enzyme responsible for the first step in succinoglycan biosynthesis. These results suggest that the level of symbiotic exopolysaccharide produced by a rhizobial species is one of the factors involved in optimizing the interaction with plant hosts.
Rhamnosyltransferase Genes
migA
and
wapR
Are Regulated in a Differential Manner To Modulate the Quantities of Core Oligosaccharide Glycoforms Produced by Pseudomonas aeruginosa
Authors: Kocíncová Dana , Ostler Sarah L. , Anderson Erin M. , Lam Joseph S. 
Published: June 2012

ABSTRACT

migA
and
wapR
are rhamnosyltransferase genes involved in the biosynthesis of
Pseudomonas aeruginosa
lipopolysaccharide core oligosaccharide. Here, we show that preferential expression of
migA
and
wapR
correlated with the levels of uncapped and O polysaccharide-capped core, respectively.
wapR
is negatively regulated, while
migA
is positively regulated by RhlR/RhlI quorum sensing.
Risk of cancer in patients using glucose-lowering agents: a nationwide cohort study of 3.6 million people
Authors: Andersson Charlotte , Vaag Allan , Selmer Christian , Schmiegelow Michelle , Sørensen Rikke , Lindhardsen Jesper , Gislason Gunnar H , Køber Lars , Torp-Pedersen Christian 
Published: June 2012

ObjectivesTo study the association between exposures to glucose-lowering therapy and risk of cancer using the nationwide administrative registers in Denmark.DesignNationwide cohort study.SettingAll hospitals in Denmark.ParticipantsAll individuals aged ≥35 years in 1998–2009 who were naive to glucose-lowering treatment and had no history of cancer. Primary measures outcomes: first cancer diagnosis between 1998 and 2009. The RR of cancer as dependent on exposure to individual glucose-lowering agents was assessed by multivariable Poisson regression models.ResultsOf 159 894 patients that initiated treatment with glucose-lowering agents, 12 789 developed cancer, incidence rate 17.4/1000 person-years. Of the remaining 3 447 904 individuals not using glucose-lowering agents, 293 878 developed cancer, incidence rate 7.9/1000 person-years. Use of different types of glucose-lowering agents including human insulin, insulin analogues, as well as sulfonylureas were associated with a quantitatively similar and significantly increased RR of cancer of 1.2–1.3 compared with unexposed individuals after multivariable adjustment. For the majority of agents, the authors identified the highest RR of cancer during the first 30 treatment days with a subsequent decline of risk approaching the cancer risk of the background population only 6–12 months after initiation of treatments.ConclusionsUse of most glucose-lowering agents including sulfonylureas was associated with a comparable increased risk of cancer shortly after initiation of treatment and subsequently a decline to the risk of the background population. This suggests that the relation is not causal.
Ambient temperature and spontaneous intracerebral haemorrhage: a cross-sectional analysis in Tainan, Taiwan
Authors: Fang Chen-Wen , Ma Mi-Chia , Lin Huey-Juan , Chen Chih-Hung 
Published: June 2012

ObjectivesAmbient temperature has been reported to play a role in the occurrence of spontaneous intracerebral haemorrhage (ICH). This study aimed to investigate the relation between ambient temperature of onset time and ICH and the effect of hourly temperature within 72 h before ICH.DesignThis is a cross-sectional case-only study and a retrospective analysis of a prospective database.SettingTwo medical centres in Southern Taiwan participating a prospective stroke registry.ParticipantsA total of 933 patients with ICH registered from August 2006 to July 2008.Primary and secondary outcome measuresThe hourly temperature was collected, and patients were grouped according to the deciles of hourly temperature at onset. Primary outcome was the association between the number of ICH cases and mean temperature (or temperature variation). Secondary outcome was the difference of onset temperature and hourly temperature before onset in patients with known onset time.ResultsWinter (n=282) had significant higher ICH cases than other seasons (n=651; p=0.002). Of those patients with an exact time of onset, the results showed 13% patients occurred at the lowest decile temperature group (<17.4°C) and 8% patients occurred at the highest decile temperature group (>30.8°C). It showed a significant temperature change before onset for these patients (p<0.005).ConclusionsThis study showed that lower ambient temperature and variation of temperatures precipitated ICH in southern Taiwan. Better protecting vulnerable people from cold temperatures may prevent the occurrences of ICH.
Smoking and suicidal behaviours in a sample of US adults with low mood: a retrospective analysis of longitudinal data
Authors: Covey Lirio S , Berlin Ivan , Hu Mei-Chen , Hakes Jahn K 
Published: June 2012

ObjectiveTo investigate whether: (1) smoking predicts suicide-related outcomes (SROs), (2) prior SRO predicts smoking, (3) smoking abstinence affects the risk of SRO and (4) psychiatric comorbidity modifies the relationship between smoking and SRO.DesignRetrospective analysis of longitudinal data obtained in wave 1 (2001–2002) and wave 2 (2004–2005) of the National Epidemiologic Survey on Alcohol and Related Conditions.SettingFace-to-face interviews conducted with persons in the community.ParticipantsUS adults (N=43 093) aged 18 years or older were interviewed in wave 1 and reinterviewed (N=34 653) 3 years later. For the present study, the sample was the subset of persons (N=7352) who at the wave 2 interview reported low mood lasting 2 weeks or more during the past 3 years and were further queried regarding SRO occurring between waves 1 and 2.Outcome measuresSRO composed of any of the following: (1) want to die, (2) suicidal ideation, (3) suicide attempt, reported at wave 2. Current smoking reported at wave 2.ResultsCurrent and former smoking in wave 1 predicted increased risk for wave 2 SRO independently of prior SRO, psychiatric history and socio-demographic characteristics measured in wave 1 (adjusted OR (AOR)=1.41, 95% CI 1.28 to 1.55 for current smoking; AOR=1.32, 95% CI 1.21 to 1.43 for former smoking). Prior SRO did not predict current smoking in wave 2. Compared with persistent never-smokers, risk for future SRO was highest among relapsers (AOR=3.42, 95% CI 2.85 to 4.11), next highest among smoking beginners at wave 2 (AOR=1.82, 95% CI 1.51 to 2.19) and lowest among long-term (4+ years) former smokers (AOR=1.22, 95% CI 1.12 to 1.34). Compared with persistent current smokers, risk for SRO was lower among long-term abstainers (p<0.0001) but not among shorter-term abstainers (p=0.26).ConclusionsSmoking increased the risk of future SRO independently of psychiatric comorbidity. Abstinence of several years duration reduced that risk.
Protocol for a population-based study of rheumatic heart disease prevalence and cardiovascular outcomes among schoolchildren in Nepal
Authors: Pilgrim Thomas , Kalesan Bindu , Karki Prahlad , Basnet Anil , Meier Bernhard , Urban Philip , Shrestha Nikesh Raj 
Published: June 2012

IntroductionRheumatic heart disease (RHD) remains a major contributor to morbidity and mortality in developing countries. The reported prevalence rates of RHD are highly variable and mainly attributable to differences in the sensitivity of either clinical screening to detect advanced heart disease or echocardiographic evaluation where disease is diagnosed earlier across a continuous spectrum. The clinical significance of diagnosis of subclinical RHD by echocardiographic screening and early implementation of secondary prevention has not been clearly established.Methods and analysisThe authors designed a cross-sectional survey to determine the prevalence of RHD in children from private and public schools between the age of 5 and 15 years in urban and rural areas of Eastern Nepal using both cardiac auscultation and echocardiographic evaluation. Children with RHD will be treated with secondary prevention and enrolled in a prospective cohort study. The authors will compare the prevalence rates by cardiac auscultation and echocardiography, determine risk factors associated with diagnosis and progression of RHD, investigate social and economic barriers for receiving adequate cardiac care and assess clinical outcomes with regular medical surveillance as a function of stage of disease at the time of diagnosis. Prospective clinical studies investigating the impact of secondary prevention for subclinical RHD on long-term clinical outcome will be of central relevance for future health resource utilisation in developing countries.Ethics and disseminationThe study was considered ethically uncritical and was given an exempt status by the ethics committee at University of Bern, Switzerland. The study has been submitted to the National Nepal Health Research Council and was registered withhttp://www.ClinicalTrials.gov(NCT01550068). The study findings will be reported in peer-reviewed publications.ClinicalTrials.gov IdentifierNCT01550068.