bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of P42 and F
1
-ATPase α-Subunit Homolog of the Gliding Machinery in Mycoplasma mobile Revealed by Newly Developed Gene Manipulation and Fluorescent Protein Tagging
Authors: Tulum Isil , Yabe Masaru , Uenoyama Atsuko , Miyata Makoto 
Published: February 2014

ABSTRACT

Mycoplasma mobile
has a unique mechanism that enables it to glide on solid surfaces faster than any other gliding mycoplasma. To elucidate the gliding mechanism, we developed a transformation system for
M. mobile
based on a transposon derived from Tn
4001
. Modification of the electroporation conditions, outgrowth time, and colony formation from the standard method for
Mycoplasma
species enabled successful transformation. A fluorescent-protein tagging technique was developed using the enhanced yellow fluorescent protein (EYFP) and applied to two proteins that have been suggested to be involved in the gliding mechanism: P42 (MMOB1050), which is transcribed as continuous mRNA with other proteins essential for gliding, and a homolog of the F
1
-ATPase α-subunit (MMOB1660). Analysis of the amino acid sequence of P42 by PSI-BLAST suggested that P42 evolved from a common ancestor with FtsZ, the bacterial tubulin homologue. The roles of P42 and the F
1
-ATPase subunit homolog are discussed as part of our proposed gliding mechanism.
A Sporulation Factor Is Involved in the Morphological Change of Clostridium perfringens Biofilms in Response to Temperature
Authors: Obana Nozomu , Nakamura Kouji , Nomura Nobuhiko 
Published: February 2014

ABSTRACT

Biofilm formation has been associated with bacterial pathogenesis, such as nosocomial and chronic infections, as the resistance of biofilms to environmental stresses has increased.
Clostridium perfringens
is a Gram-positive spore-forming anaerobic pathogen. This organism survives antibiotic treatment through the formation of biofilms or spores, but the environmental and regulatory factors involved in the biofilm formation remain unclear. Here, we observed that temperature regulates
C. perfringens
biofilm morphology. At 37°C,
C. perfringens
adhered to the substrate surface and formed a flat, thin biofilm, herein referred to as adhered biofilm. However, at 25°C, this bacterium did not adhere and produced a threadlike extracellular matrix, forming a viscous, thick biofilm, herein referred to as pellicle biofilm. Pellicle biofilm formation requires the sporulation master regulator, Spo0A, and the toxin regulator, CtrAB, and is enhanced in the absence of the global repressor, AbrB. These transcriptional regulator genes are regulated by each other and temperature. Adhered-biofilm formation requires AbrB and
pilA2
, which encodes a component of type IV pili (TFP). TFP expression was activated at 37°C and regulated through Spo0A, AbrB, and CtrAB. These results indicate that the morphology of
C. perfringens
biofilm is dependent on temperature through the differential production of extracellular matrix and the activity of TFP. Moreover, pellicle biofilm formation is involved in sporulation and toxin production. Here, we demonstrated that clostridial biofilm formation is closely associated with sporulation and that the morphological change of the biofilms could play an important role in the pathogenesis of this organism.
Plasmid Conjugation from Proteobacteria as Evidence for the Origin of Xenologous Genes in Cyanobacteria
Authors: Encinas David , Garcillán-Barcia M. Pilar , Santos-Merino María , Delaye Luis , Moya Andrés , de la Cruz Fernando 
Published: February 2014

ABSTRACT

Comparative genomics have shown that 5% of
Synechococcus elongatus
PCC 7942 genes are of probable proteobacterial origin. To investigate the role of interphylum conjugation in cyanobacterial gene acquisition, we tested the ability of a set of prototype proteobacterial conjugative plasmids (RP4, pKM101, R388, R64, and F) to transfer DNA from
Escherichia coli
to
S. elongatus
. A series of BioBrick-compatible, mobilizable shuttle vectors was developed. These vectors were based on the putative origin of replication of the
Synechococcus
resident plasmid pANL. Not only broad-host-range plasmids, such as RP4 and R388, but also narrower-host-range plasmids, such as pKM101, all encoding MPF
T
-type IV secretion systems, were able to transfer plasmid DNA from
E. coli
to
S. elongatus
by conjugation. Neither MPF
F
nor MPF
I
could be used as interphylum DNA delivery agents. Reciprocally, pANL-derived cointegrates could be introduced in
E. coli
by electroporation, where they conferred a functional phenotype. These results suggest the existence of potentially ample channels of gene flow between proteobacteria and cyanobacteria and point to MPF
T
-based interphylum conjugation as a potential mechanism to explain the proteobacterial origin of a majority of
S. elongatus
xenologous genes.
Cyclic AMP Receptor Protein Regulates
cspD
, a Bacterial Toxin Gene, in Escherichia coli
Authors: Uppal Sheetal , Shetty Deeksha M. , Jawali Narendra 
Published: February 2014

ABSTRACT

cspD
, a member of
cspA
family of cold shock genes in
Escherichia coli
, is not induced during cold shock. Its expression is induced during stationary phase. CspD inhibits DNA replication, and a high level of the protein is toxic to cells. Recently, CspD was proposed to be associated with persister cell formation in
E. coli
. Here, we show that cyclic AMP receptor protein (CRP) upregulates
cspD
transcription. Sequence analysis of the
cspD
upstream region revealed two tandem CRP target sites, CRP site-I (the proximal site centered at −83.5 with respect to the transcription start) and CRP site-II (the distal site centered at −112.5). The results from electrophoretic mobility shift assays showed that CRP indeed binds to these two target sites in P
cspD
. The promoter-proximal CRP target site was found to play a major role in P
cspD
activation by CRP, as studied by transcriptional fusions carrying mutations in the target sites. The results from
in vitro
transcription assays demonstrated that CRP activates P
cspD
transcription in the absence of additional factors other than RNA polymerase. The requirement for activating region 1 of CRP in P
cspD
activation, along with the involvement of the 287, 265, and 261 determinants of the α-CTD, suggest that CRP activates by a class I-type mechanism. However, only moderate activation
in vitro
was observed compared to high activation
in vivo
, suggesting there might be additional activators of P
cspD
. Overall, our findings show that CRP, a global metabolic regulator in
E. coli
, activates a gene potentially related to persistence.
The Hypervariable Region of Meningococcal Major Pilin PilE Controls the Host Cell Response via Antigenic Variation
Authors: Miller Florence , Phan Gilles , Brissac Terry , Bouchiat Coralie , Lioux Ghislaine , Nassif Xavier , Coureuil Mathieu 
Published: February 2014

ABSTRACT

T
ype IV pili (Tfp) are expressed by many Gram-negative bacteria to promote aggregation, adhesion, internalization, twitching motility, or natural transformation. Tfp of
Neisseria meningitidis
, the causative agent of cerebrospinal meningitis, are involved in the colonization of human nasopharynx. After invasion of the bloodstream, Tfp allow adhesion of
N. meningitidis
to human endothelial cells, which leads to the opening of the blood-brain barrier and meningitis. To achieve firm adhesion,
N. meningitidis
induces a host cell response that results in elongation of microvilli surrounding the meningococcal colony. Here we study the role of the major pilin subunit PilE during host cell response using human dermal microvascular endothelial cells and the pharynx carcinoma-derived FaDu epithelial cell line. We first show that some PilE variants are unable to induce a host cell response. By engineering PilE mutants, we observed that the PilE C-terminus domain, which contains a disulfide bonded region (D-region), is critical for the host cell response and that hypervariable regions confer different host cell specificities. Moreover, the study of point mutants of the pilin D-region combined with structural modeling of PilE revealed that the D-region contains two independent regions involved in signaling to human dermal microvascular endothelial cells (HDMECs) or FaDu cells. Our results indicate that the diversity of the PilE D-region sequence allows the induction of the host cell response via several receptors. This suggests that
Neisseria meningitidis
has evolved a powerful tool to adapt easily to many niches by modifying its ability to interact with host cells.

IMPORTANCE
Type IV pili (Tfp) are long appendages expressed by many Gram-negative bacteria, including
Neisseria meningitidis
, the causative agent of cerebrospinal meningitis. These pili are involved in many aspects of pathogenesis: natural competence, aggregation, adhesion, and twitching motility. More specifically,
Neisseria meningitidis
, which is devoid of a secretion system to manipulate its host, has evolved its Tfp to signal to brain endothelial cells and open the blood-brain barrier. In this report, we investigate, at the molecular level, the involvement of the major pilin subunit PilE in host cell response. Our results indicate that the PilE C-terminal domain, which contains a disulfide bonded region (D-region), is critical for the host cell response and contains two independent regions involved in host cell signaling.
Haemophilus ducreyi Hfq Contributes to Virulence Gene Regulation as Cells Enter Stationary Phase
Authors: Gangaiah Dharanesh , Labandeira-Rey Maria , Zhang Xinjun , Fortney Kate R. , Ellinger Sheila , Zwickl Beth , Baker Beth , Liu Yunlong , Janowicz Diane M. , Katz Barry P. , Brautigam Chad A. , Munson Robert S. , Hansen Eric J. , Spinola Stanley M. 
Published: February 2014

ABSTRACT

To adapt to stresses encountered in stationary phase, Gram-negative bacteria utilize the alternative sigma factor RpoS. However, some species lack RpoS; thus, it is unclear how stationary-phase adaptation is regulated in these organisms. Here we defined the growth-phase-dependent transcriptomes of
Haemophilus ducreyi
, which lacks an RpoS homolog. Compared to mid-log-phase organisms, cells harvested from the stationary phase upregulated genes encoding several virulence determinants and a homolog of
hfq
. Insertional inactivation of
hfq
altered the expression of ~16% of the
H. ducreyi
genes. Importantly, there were a significant overlap and an inverse correlation in the transcript levels of genes differentially expressed in the
hfq
inactivation mutant relative to its parent and the genes differentially expressed in stationary phase relative to mid-log phase in the parent. Inactivation of
hfq
downregulated genes in the
flp-tad
and
lspB-lspA2
operons, which encode several virulence determinants. To comply with FDA guidelines for human inoculation experiments, an unmarked
hfq
deletion mutant was constructed and was fully attenuated for virulence in humans. Inactivation or deletion of
hfq
downregulated Flp1 and impaired the ability of
H. ducreyi
to form microcolonies, downregulated DsrA and rendered
H. ducreyi
serum susceptible, and downregulated LspB and LspA2, which allow
H. ducreyi
to resist phagocytosis. We propose that, in the absence of an RpoS homolog, Hfq serves as a major contributor of
H. ducreyi
stationary-phase and virulence gene regulation. The contribution of Hfq to stationary-phase gene regulation may have broad implications for other organisms that lack an RpoS homolog.

IMPORTANCE
Pathogenic bacteria encounter a wide range of stresses in their hosts, including nutrient limitation; the ability to sense and respond to such stresses is crucial for bacterial pathogens to successfully establish an infection. Gram-negative bacteria frequently utilize the alternative sigma factor RpoS to adapt to stresses and stationary phase. However, homologs of RpoS are absent in some bacterial pathogens, including
Haemophilus ducreyi
, which causes chancroid and facilitates the acquisition and transmission of HIV-1. Here, we provide evidence that, in the absence of an RpoS homolog, Hfq serves as a major contributor of stationary-phase gene regulation and that Hfq is required for
H. ducreyi
to infect humans. To our knowledge, this is the first study describing Hfq as a major contributor of stationary-phase gene regulation in bacteria and the requirement of Hfq for the virulence of a bacterial pathogen in humans.
Determinants of concurrent sexual partnerships within stable relationships: a qualitative study in Tanzania
Authors: Cox Carie Muntifering , Babalola Stella , Kennedy Caitlin E , Mbwambo Jessie , Likindikoki Samuel , Kerrigan Deanna 
Published: February 2014

ObjectiveConcurrent sexual partnerships (CP) have been identified as a potential driver in the HIV epidemic in southern Africa, making it essential to understand motivating factors for engagement in CP. We aimed to assess community attitudes and beliefs about relationship factors that influence men and women in stable relationships to engage in CP in Tanzania. Social exchange theory was used for interpreting the data.DesignQualitative study with focus group discussions (FGDs).SettingSemiurban/rural communities in four regions across Tanzania (Dar es Salaam, Shinyanga, Iringa and Mbeya).Participants120 women aged 17–45 years and 111 men aged 18–49 years from four study areas participated in 32 FGDs.Outcome measuresFGD participants were asked the following questions about CP: definitions and types, motivations and justifications for engaging or not engaging, cultural factors, gender and socialisation, and local resources and efforts available for addressing CP. Our analysis focused specifically on beliefs about how relationship factors influence engagement in CP.ResultsDissatisfaction with a stable relationship was believed to be a contributing factor for engagement in CP for both men and women. Participants more commonly reported financial dissatisfaction as a contributing factor for women engaging in CP within stable relationships, whereas emotional and sexual dissatisfaction were reported as contributing factors for men and women. Furthermore, participants described how potential outside partners are often evaluated based on what they are able to offer compared with stable partners.ConclusionsEfforts to reach men and women in stable relationships with HIV prevention messages must consider the various dimensions of motivation for engaging in CP, including relationship dynamics.
Relationship between patient reported experience (PREMs) and patient reported outcomes (PROMs) in elective surgery
Authors: Black Nick , Varaganum Mira , Hutchings Andrew 
Published: February 2014

ObjectiveOur aim was to see if the reporting of better experiences by elective surgical patients was associated with better outcomes (effectiveness and safety). The objectives were to: describe the distribution of experience scores and any association with patients’ characteristics; determine the relationship of experience with effectiveness and with safety; and explore the influence of patient characteristics, year and provider on the relationship between experience and effectiveness.MethodsPatients undergoing one of three procedures from 2010 to 2012 in England who completed a patient reported outcome measure (PROM) questionnaire before and after surgery and a patient reported experience measure (PREM) questionnaire. Data on 4089 hip replacement patients, 4501 knee replacements and 1793 groin hernia repairs. Regression analysis was used to examine associations between disease-specific and generic PROMs and PREMs.ResultsThere was a weak positive association between experience and effectiveness for all three procedures (correlation coefficient with disease-specific PROMs for hip and knee replacements 0.2 and with EQ-5D 0.1 for all three procedures). The aspect of experience most strongly associated with a better outcome was the level of communication with and trust in their doctor. A higher experience score of 1 SD (about 1.5 on a 10-point scale) was associated with about 30% less likelihood of the patient reporting a complication. There was no difference between the eight dimensions of experience.All the relationships observed were consistent over time, between different types of patients (age, sex, socioeconomic status) and between providers.ConclusionsPatients distinguish between the three domains of quality when reporting their experience and outcome. If the weak positive associations between domains were shown to be causal, there would be implications for maximising performance measures for providers.
Elective treatment of intracranial stenosis with the balloon-expandable Pharos Vitesse stent: 30-day stroke rate and complications
Authors: von Schoenfeldt Patrick , Krützelmann Anna , Bußmeyer Matthias , Mpotsaris Anastasios , Rosenkranz Michael , Fiehler Jens , Weber Werner , Buhk Jan-Hendrik 
Published: February 2014

Background and purposeAnalysis of procedural results and 30-day outcome after intracranial angioplasty and stenting (ICAS) with the balloon-expandable Pharos Vitesse stent system in carefully selected high-risk patients in two high-volume neurovascular centers.Materials and methods92 patients scheduled for elective ICAS using Pharos Vitesse between August, 2008 and August, 2011 were included. All patients showed high-grade intracranial stenosis and recurrent ischemic events despite best medical treatment at that time. The stroke rates and complications were divided into procedural and 30-day short-term events.ResultsSuccessful stent placement was achieved in all but one patient. Ischemic procedural complications occurred in three subjects. 30-Day complications and strokes were seen in four patients: two minor ischemic strokes, one fatal hemorrhage and one non-stroke-related death. Overall, strokes occurred in 6 out of 92 patients (6.5%, 95% CI 3.0% to 13.5%). The total stroke and death rate was 7.6% (95% CI 3.7% to 14.9%). No significant correlation with previously reported risk factors could be found, although a higher rate of ischemic strokes (four out of five) in the posterior circulation was recorded.ConclusionsIn patients with intracranial stenosis who experience recurrent ischemic events despite best medical treatment, ICAS, using the balloon-expandable Pharos Vitesse stent, may still be considered as an individual treatment option in high-volume neurovascular centers.
Synergistic Interaction between the HDAC Inhibitor, MPT0E028, and Sorafenib in Liver Cancer Cells In Vitro and In Vivo
Authors: Chen Chun-Han , Chen Mei-Chuan , Wang Jing-Chi , Tsai An-Chi , Chen Ching-Shih , Liou Jing-Ping , Pan Shiow-Lin , Teng Che-Ming 
Published: February 2014

Abstract
Purpose: To investigate the antitumor activities of a histone deacetylase (HDAC) inhibitor, MPT0E028, plus sorafenib in liver cancer cells in vitro and in vivo.
Experimental Design: Different liver cancer cell lines were exposed to sorafenib in the presence or absence of MPT0E028, and cell viability was determined by MTT assay. Effects of combined treatment on cell cycle and intracellular signaling pathways were assessed by flow cytometry and Western blot analysis. The Hep3B xenograft model was used to examine the antitumor activity in vivo.
Results: Our data indicate that sorafenib and MPT0E028 synergistically reduced cell viability in liver cancer cells, and also markedly induced apoptotic cell death in these cells, as evidenced by the cleavage of caspase-3, PARP, and DNA fragmentation. MPT0E028 altered the global modifications of histone and nonhistone proteins regardless of the presence of sorafenib. However, sorafenib blocked MPT0E028-induced Erk activation and its downstream signaling cascades, such as Stat3 phosphorylation (Ser727) and Mcl-1 upregulation. Ectopic expression of constitutively active Mek successively reversed the apoptosis triggered by the combined treatment. Pharmacologic inhibition of Mek by PD98059 potentiated MPT0E028-induced apoptosis, suggesting that the synergistic interaction between MPT0E028 and sorafenib occurs at least partly through inhibition of Erk signaling. The data demonstrated that transcriptional activation of fibroblast growth factor receptor 3 (FGFR3) contributes to MPT0E028-mediated Erk phosphorylation. Finally, MPT0E028 plus sorafenib significantly improved the tumor growth delay (TGD) in a Hep3B xenograft model.
Conclusions: These findings suggest that MPT0E028 in combination with sorafenib has significant anti-hepatocellular carcinoma activity in preclinical models, potentially suggesting a novel therapeutic strategy for patients with advanced hepatocellular carcinoma. Clin Cancer Res; 20(5); 1274–87. ©2014 AACR.
Prevalence of Inferobasal Myocardial Crypts Among Patients Referred for Cardiovascular Magnetic Resonance
Authors: Petryka Joanna , Baksi A. John , Prasad Sanjay K. , Pennell Dudley J. , Kilner Philip J. 
Published: February 2014

Background—
Crypts or clefts in the left ventricular inferobasal myocardium have been detected by cardiovascular magnetic resonance (CMR), but the extent to which they represent prephenotypic markers of hypertrophic cardiomyopathy (HCM) or incidental structural variants remains controversial.

Methods and Results—

We examined retrospectively the routine vertical long-axis cines in 686 consecutive patients (48±20 years, 55% men) referred for CMR. Crypts were identified in 46 (6.7%), 17 being among patients (8.7% of 196) with otherwise normal CMR findings and without a known family history of HCM. Higher percentages were found in patients with HCM (16%), myocarditis (15%), and hypertension (14%) but without reaching statistical significance (
P
=0.12). Only 1 (5%) of 20 phenotype -negative HCM family members had a visible crypt. Relative to those without, patients with crypts had lower indexed left ventricular end-systolic volumes (
P
=0.042) and higher indexed left and right ventricular stroke volumes (
P
=0.007 and
P
=0.015) and ejection fractions (
P
=0.003 and
P
=0.021). Crypts tended to narrow in systole, varying slightly in size, shape- and number, without obvious group-related features.

Conclusions—
Single or paired inferobasal myocardial crypts were an occasional and by no means rare finding among patients referred for CMR without a pretest suspicion of HCM. This, together with similar previous findings in a cohort of healthy volunteers, supports their being regarded, in such individuals, as incidental variants of local myocardial structure, unlikely to require further investigation. However, a larger registry-type study may be justified to investigate the clinical implications of multiple crypts, especially if associated with HCM family history.