bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serological Diagnosis of Lung Cystic Hydatid Disease Using the Synthetic p176 Peptide
Authors: Santivañez Saul J. , Arias Patricia , Portocarrero Milagrytos , Rodriguez Silvia , Gonzalez Armando E. , Gilman Robert H. , Gavidia Cesar M. , Garcia Hector H. 
Published: April 2012

ABSTRACT

Cystic hydatid disease (CHD) is a worldwide zoonosis caused by the larval stage of the dog tapeworm
Echinococcus granulosus
. Diagnosis is based on imagenological tools (abdominal ultrasound, chest X-rays, or computed tomography [CT] scan). Serological antibody-detecting assays, using diverse native antigens, have been used as a supportive diagnostic tool, but their sensitivities and specificities differ greatly. The use of synthetic peptides as antigens should provide more reliability and allow better assessment and comparison of test formats and case series. The synthetic peptide p176, corresponding to the N-terminal extreme of the subunit of antigen B (AgB8/1), has shown promising performances for diagnosis of CHD. We evaluated the performance of the synthetic peptide p176 for the diagnosis of pulmonary hydatid disease in an enzyme-linked immunosorbent assay (ELISA) format. Sixty-one serum samples from patients with a diagnosis of pulmonary hydatidosis confirmed by surgery and 128 from healthy volunteers were tested. The overall sensitivity and specificity of the p176 ELISA for lung CHD were 78.69% and 96.88%, respectively. On bivariate analysis, positive serum antibody reactions were associated with the presence of complications and with the number of cysts (single/multiple). Only the presence of persistent complications significantly associated with seropositivity on multivariate logistic regression analysis (odds ratio [OR], 9.58; 95% confidence interval [CI], 2.15 to 42.6;
P
= 0.003). The p176 ELISA performs well for the diagnosis of lung CHD and adds an easily reproducible diagnostic assay to the existing diagnostic tools.
Insight into the Antiadhesive Effect of Yeast Wall Protein 1 of Candida albicans
Authors: Granger Bruce L. 
Published: April 2012

ABSTRACT

Ywp1 is a prominent glycosylphosphatidylinositol (GPI)-anchored glycoprotein of the cell wall of
Candida albicans
; it is present in the yeast form of this opportunistic fungal pathogen but absent from filamentous forms and chlamydospores. Yeast cells that lack Ywp1 are more adhesive and form thicker biofilms, implying an antiadhesive activity for Ywp1, with a possible role in yeast dispersal. The antiadhesive effect of Ywp1 is transplantable from yeast to hyphae, as hyphae that are forced to express
YWP1
lose adhesion in an
in vitro
assay. Deletion of the GPI anchor results in loss of Ywp1 to the surrounding medium and reduction of the antiadhesive effect, implying an importance of time-dependent residency in the cell wall. Anchor-negative versions of Ywp1 possessing or lacking a C-terminal green fluorescent protein (GFP) tag were created in
C. albicans
and harvested from culture supernatants; in addition to serving as quantifiable markers for Ywp1 secretion, they revealed that the cleaved 11-kDa propeptide of Ywp1 remains strongly but noncovalently associated with the Ywp1 core. This association is resistant to highly acidic and basic solutions, 8 M urea, and 1% SDS (below 45°C). Above 50°C, SDS dissociates the isolated complex, but even higher temperatures are required to dissociate the propeptide from native Ywp1 that is anchored in a cell wall. This property has permitted detection, for the first time, of orthologs of Ywp1 in other members of the
Candida
clade. The cleaved propeptide, which carries the sole N-glycan of Ywp1, must participate in the antiadhesive effect of Ywp1.
Exposure to Host Ligands Correlates with Colocalization of Gal/GalNAc Lectin Subunits in Lipid Rafts and Phosphatidylinositol (4,5)-Bisphosphate Signaling in Entamoeba histolytica
Authors: Goldston Amanda M. , Powell Rhonda R. , Koushik Amrita B. , Temesvari Lesly A. 
Published: April 2012

ABSTRACT

Entamoeba histolytica
is an intestinal parasite that causes dysentery and liver abscess. Parasite cell surface receptors, such as the Gal/GalNAc lectin, facilitate attachment to host cells and extracellular matrix. The Gal/GalNAc lectin binds to galactose or
N
-acetylgalactosamine residues on host components and is composed of heavy (Hgl), intermediate (Igl), and light (Lgl) subunits. Although Igl is constitutively localized to lipid rafts (cholesterol-rich membrane domains), Hgl and Lgl transiently associate with this compartment in a cholesterol-dependent fashion. In this study, trophozoites were exposed to biologically relevant ligands to determine if ligand binding influences the submembrane distribution of the subunits. Exposure to human red blood cells (hRBCs) or collagen, which are
bona fide
Gal/GalNAc lectin ligands, was correlated with enrichment of Hgl and Lgl in rafts. This enrichment was abrogated in the presence of galactose, suggesting that direct lectin-ligand interactions are necessary to influence subunit location. Using a cell line that is able to attach to, but not phagocytose, hRBCs, it was shown that physical attachment to ligands was not sufficient to induce the enrichment of lectin subunits in rafts. Additionally, the mutant had lower levels of phosphatidylinositol (4,5)-bisphosphate (PIP
2
); PIP
2
loading restored the ability of this mutant to respond to ligands with enrichment of subunits in rafts. Finally, intracellular calcium levels increased upon attachment to collagen; this increase was essential for the enrichment of lectin subunits in rafts. Together, these data provide evidence that ligand-induced enrichment of lectin subunits in rafts may be the first step in a signaling pathway that involves both PIP
2
and calcium signaling.
The
ttpC
Gene Is Contained in Two of Three TonB Systems in the Human Pathogen Vibrio vulnificus, but Only One Is Active in Iron Transport and Virulence
Authors: Kustusch Ryan J. , Kuehl Carole J. , Crosa Jorge H. 
Published: April 2012

ABSTRACT

The TonB system of proteins is required for the energy-dependent active transport of iron-bound substrates across the outer membrane of Gram-negative bacteria. We have identified three TonB systems within the human pathogen
Vibrio vulnificus
. The TonB1 system contains the TonB1, ExbD1, and ExbB1 proteins, whereas both the TtpC2-TonB2 and TtpC3-TonB3 systems contain an additional fourth protein, TtpC. Here we report that TtpC3, although highly related to TtpC2, is inactive in iron transport, whereas TtpC2 is essential for the function of the TtpC2-TonB2 system in
V. vulnificus
. This protein, together with TonB2, is absolutely required for both the uptake of endogenously produced iron-bound siderophores as well as siderophores produced from other organisms. Through complementation we show that
V. vulnificus
is capable of using different TtpC2 proteins from other
Vibrio
species to drive the uptake of multiple siderophores. We have also determined that aerobactin, a common bacterial siderophore involved in virulence of enteric bacteria, can only be brought into the cell using the TtpC2-TonB2 system, indicating an important evolutionary adaptation of TtpC2 and TonB2. Furthermore, in the absence of TonB1, TtpC2 is essential for a fully virulent phenotype as demonstrated using 50% lethal dose (LD
50
) experiments in mice.
Regulation and Evolution of Malonate and Propionate Catabolism in Proteobacteria
Authors: Suvorova I. A. , Ravcheev D. A. , Gelfand M. S. 
Published: April 2012

ABSTRACT

Bacteria catabolize malonate via two pathways, encoded by the
mdc
and
mat
genes. In various bacteria, transcription of these genes is controlled by the GntR family transcription factors (TFs) MatR/MdcY and/or the LysR family transcription factor MdcR. Propionate is metabolized via the methylcitrate pathway, comprising enzymes encoded by the
prp
and
acn
genes. PrpR, the Fis family sigma 54-dependent transcription factor, is known to be a transcriptional activator of the
prp
genes. Here, we report a detailed comparative genomic analysis of malonate and propionate metabolism and its regulation in proteobacteria. We characterize genomic loci and gene regulation and identify binding motifs for four new TFs and also new regulon members, in particular, tripartite ATP-independent periplasmic (TRAP) transporters. We describe restructuring of the genomic loci and regulatory interactions during the evolution of proteobacteria.
SMU.152 Acts as an Immunity Protein for Mutacin IV
Authors: Hossain Mohammad Shahnoor , Biswas Indranil 
Published: April 2012

ABSTRACT

Streptococcus mutans
, a principal causative agent of dental caries, secretes antimicrobial peptides known as mutacins to suppress the growth of competing species to establish a successful colonization.
S. mutans
UA159, a sequenced strain, produces at least two major mutacins, mutacins IV and V. Mutacin IV is a two-peptide mutacin encoded by
nlmAB
genes, which are mapped just upstream of a putative immunity-encoding gene SMU.152. Here we explored the function of SMU.152 as an immunity protein. We observed that overexpression of SMU.152 in two sensitive host strains converted the strains to become immune to mutacin IV. To identify the residues that are important for immunity function, we sequentially deleted residues from the C-terminal region of SMU.152. We observed that deletion of as few as seven amino acids, all of which are highly charged (KRRSKNK), drastically reduced the immunity function of the protein. Furthermore, we identified two other putative immunity proteins, SMU.1909 and SMU.925, which lack the last four charged residues (SKNK) that are present in SMU.152 but contain the KRR residues. Synthetic addition of SKNK residues to either SMU.1909 or SMU.925 to reconstitute the KRRSKNK motif and expressing these constructs in sensitive cells rendered the cells resistant to mutacin IV. We also demonstrated that deletion of Man-PTS system from a sensitive strain made the cells partially resistant to mutacin IV, indicating that the Man-PTS system plays a role in mutacin IV recognition.
Differential Effects of DNA Supercoiling on Chlamydia Early Promoters Correlate with Expression Patterns in Midcycle
Authors: Cheng Eric , Tan Ming 
Published: April 2012

ABSTRACT

Changes in DNA supercoiling levels during the chlamydial developmental cycle have been proposed as a global mechanism to upregulate midcycle genes, but the effects on early genes are not known. We examined the promoters for 10
Chlamydia trachomatis
early genes and found that they could be separated into two subsets based on their responses to DNA supercoiling
in vitro
. Furthermore, the type of supercoiling response correlated with the
in vivo
expression pattern for each early gene. One subset of seven early genes had promoters that were transcribed in a supercoiling-insensitive manner over the physiologic range of supercoiling levels that have been measured in
Chlamydia
.
In vivo
transcripts for these genes were detected at similar levels during early-stage and midstage times. In contrast, a second subset, represented in our study by three early genes, had supercoiling-dependent promoters that were transcribed at higher levels from more-supercoiled templates, which is the response observed for midcycle genes. Genes in this subset were expressed at higher levels at midstage times than at early times
in vivo
. We propose that this second subset represents a novel class of chlamydial developmental genes with features of both early and midcycle genes. We hypothesize that expression of these supercoiling-dependent early genes is upregulated by increased chlamydial supercoiling levels in midcycle via their supercoiling-responsive promoters in a manner similar to that for midcycle genes. Thus, we propose that DNA supercoiling is utilized in
Chlamydia
as a general mechanism to regulate genes in the midstage of the developmental cycle and not just midcycle genes.
The Bacillus subtilis Conjugative Transposon ICEBs1Mobilizes Plasmids Lacking Dedicated Mobilization Functions
Authors: Lee Catherine A. , Thomas Jacob , Grossman Alan D. 
Published: April 2012

ABSTRACTIntegrative and conjugative elements (ICEs, also known as conjugative transposons) are mobile elements that are found integrated in a host genome and can excise and transfer to recipient cells via conjugation. ICEs and conjugative plasmids are found in many bacteria and are important agents of horizontal gene transfer and microbial evolution. Conjugative elements are capable of self-transfer and also capable of mobilizing other DNA elements that are not able to self-transfer. Plasmids that can be mobilized by conjugative elements are generally thought to contain an origin of transfer (oriT), from which mobilization initiates, and to encode a mobilization protein (Mob, a relaxase) that nicks a site inoriTand covalently attaches to the DNA to be transferred. Plasmids that do not have both anoriTand a cognatemobare thought to be nonmobilizable. We found thatBacillus subtiliscarrying the integrative and conjugative element ICEBs1can transfer three different plasmids to recipient bacteria at high frequencies. Strikingly, these plasmids do not have dedicated mobilization-oriTfunctions. Plasmid mobilization required conjugation proteins of ICEBs1, including the putative coupling protein. In contrast, plasmid mobilization did not require the ICEBs1conjugative relaxase or cotransfer of ICEBs1, indicating that the putative coupling protein likely interacts with the plasmid replicative relaxase and directly targets the plasmid DNA to the ICEBs1conjugation apparatus. These results blur the current categorization of mobilizable and nonmobilizable plasmids and indicate that conjugative elements play a role in horizontal gene transfer even more significant than previously recognized.
Roles of Exc Protein and DNA Homology in the CTnDOT Excision Reaction
Authors: Keeton Carolyn M. , Gardner Jeffrey F. 
Published: April 2012

ABSTRACT

Excision from the chromosome is the first step during the transfer of conjugative transposons (CTns) to a recipient. We previously showed that the excision of CTnDOT is more complex than the excision of lambdoid phages and CTns such as Tn
916
. The excision
in vivo
of CTnDOT utilizes four CTnDOT-encoded proteins, IntDOT, Xis2c, Xis2d, and Exc, and a host factor. We previously developed an
in vitro
excision reaction where the recombination sites
attL
and
attR
were located on different plasmids. The reaction was inefficient and did not require Exc, suggesting that the reaction conditions did not mimic
in vivo
conditions. Here, we report the development of an intramolecular excision reaction where the
attL
and
attR
sites are located on the same DNA molecule. We found that Exc stimulates the reaction 3- to 5-fold. The efficiency of the excision reaction was also dependent on the distance between the
attL
and
attR
sites and on the sequences of the overlap regions between the sites of the strand exchanges. Substrates with identical overlap sequences recombined more efficiently than ones with heterologous overlap sequences. This was surprising, because the integration reaction is not sensitive to heterology in the overlap regions of the
attDOT
and
attB
sites.
The Biofilm-Specific Antibiotic Resistance Gene
ndvB
Is Important for Expression of Ethanol Oxidation Genes in Pseudomonas aeruginosa Biofilms
Authors: Beaudoin Trevor , Zhang Li , Hinz Aaron J. , Parr Christopher J. , Mah Thien-Fah 
Published: April 2012

ABSTRACT

Bacteria growing in biofilms are responsible for a large number of persistent infections and are often more resistant to antibiotics than are free-floating bacteria. In a previous study, we identified a
Pseudomonas aeruginosa
gene,
ndvB
, which is important for the formation of periplasmic glucans. We established that these glucans function in biofilm-specific antibiotic resistance by sequestering antibiotic molecules away from their cellular targets. In this study, we investigate another function of
ndvB
in biofilm-specific antibiotic resistance. DNA microarray analysis identified 24 genes that were responsive to the presence of
ndvB
. A subset of 20 genes, including 8 ethanol oxidation genes (
ercS
′,
erbR
,
exaA
,
exaB
,
eraR
,
pqqB
,
pqqC
, and
pqqE
), was highly expressed in wild-type biofilm cells but not in Δ
ndvB
biofilms, while 4 genes displayed the reciprocal expression pattern. Using quantitative real-time PCR, we confirmed the
ndvB
-dependent expression of the ethanol oxidation genes and additionally demonstrated that these genes were more highly expressed in biofilms than in planktonic cultures. Expression of
erbR
in Δ
ndvB
biofilms was restored after the treatment of the biofilm with periplasmic extracts derived from wild-type biofilm cells. Inactivation of ethanol oxidation genes increased the sensitivity of biofilms to tobramycin. Together, these results reveal that
ndvB
affects the expression of multiple genes in biofilms and that ethanol oxidation genes are linked to biofilm-specific antibiotic resistance.
Poor sensitivity of musculoskeletal history in children
Authors: Goff Iain , Rowan Amy , Bateman Belinda Jane , Foster Helen Elizabeth 
Published: April 2012

ObjectivesTo demonstrate the sensitivity of musculoskeletal (MSK) history taking.DesignProspective study: consecutive children attending outpatient clinics.Setting and patientsPaediatric rheumatology clinic (n=45; girls n=28; median age 12 years, range 3–18), acute general paediatric assessment unit (n=50; girls n=21; median age 8 years, range 3–16).InterventionPro forma recording abnormal joint involvement from history taking and then following MSK examination completed by clinicians.Main outcome measuresSensitivity of MSK history taking compared with clinical examination.ResultsPaediatric rheumatology clinic: 135 abnormal joints identified in 34 children; 53/135 (39%) by history alone, 82/135 (61%) detected on examination resulting in MSK history sensitivity 53%, specificity 98%. Acute paediatric unit: 29 abnormal joints identified in 17 children; 18/29 identified on history (sensitivity 62%).ConclusionsMSK history taking failed to identify a large number of abnormal joints which were detected on physical examination, emphasising the need for all joints to be examined as part of a screening examination as a minimum.
Sensitivity and specificity of CT scan and angiogram for ongoing internal bleeding following torso trauma
Authors: Ahmed Nasim , Kassavin Daniel , Kuo Yen-Hong , Biswal Rajiv 
Published: April 2012

BackgroundOccult internal bleeding in the trauma patient which remains undiagnosed and unaddressed has the potential to result in morbidity or mortality. Advancements in CT and angiography have played an integral role in the management of this patient population.ObjectiveThe purpose of the study was to identify the sensitivity and specificity of CT scan and angiography in detecting ongoing internal bleeding.MethodsConsecutive patients who sustained torso trauma and subsequently underwent CT scan and angiography were included in this study. Data reviewed included clinical information, CT scan and angiography readings. Extravasations of contrast from CT scan and/or angiogram were considered positive for ongoing internal bleeding.ResultsFrom January 2002 through July 2007, 113 adult trauma patients sustaining torso trauma underwent CT scan of chest or abdomen followed by angiography. Sixty-six patients were negative for extravasation from either of the tests. Twenty-four of 35 patients had both positive CT scans and angiograms. Eleven patients with positive CT scans did not have bleeding on angiogram. Similarly, 12 out of 36 patients with positive angiograms did not show any extravasation of contrast on CT scan. Both modalities had a specificity of 100% based on clinical definition. The sensitivities of CT scan and angiogram were 74.5% and 76.6%, respectively. They were not significantly different (p=0.95). The negative predictive values for CT and angiogram were 84.6% and 85.7%. They were not significantly different (p=0.95) either. When CT scan was used alone, 25.5% of bleeding patients were missed.ConclusionsThe sensitivity of CT scan and angiography at detecting ongoing bleeding was around 75% across the torso injury spectrum.
Improving documentation in prehospital rapid sequence intubation: investigating the use of a dedicated airway registry form
Authors: Bloomer Roger , Burns Brian J , Ware Sandra 
Published: April 2012

ObjectiveThe quality of medical documentation is integral to audit, clinical governance, education, medico-legal aspects and continuity of patient care. This study aims to investigate the introduction of a dedicated ‘Airway Registry Form’ (ARF) on the quality of documentation in prehospital rapid sequence intubation.MethodsA retrospective review and comparison of 96 cases predating the introduction of the ARF and 90 cases immediately following its introduction were performed.ResultsThe introduction of the ARF yielded significant improvement in the recording of selected data points: difficult airway indicators (p<0.0001), Cormack–Lehane grade of laryngoscopy at first attempt (p<0.0001), documentation of confirmation of tracheal intubation with end-tidal carbon dioxide monitoring (p=0.015) and recording of intubator's details (p<0.0001).ConclusionsThis study validates the use of a dedicated ARF for the improvement of documentation and data collection related to prehospital rapid sequence intubation when compared with post-event extraction of data from a generic case-record.
Efficacy of the Disposcope endoscope, a new video laryngoscope, for endotracheal intubation in patients with cervical spine immobilisation by semirigid neck collar: comparison with the Macintosh laryngoscope using a simulation study on a manikin
Authors: Park Sang O , Shin Dong Hyuk , Lee Kyeong Ryong , Hong Dae Young , Kim Eun Jung , Baek Kwang Je 
Published: April 2012

ObjectiveTo evaluate whether endotracheal intubation in patients with cervical spine immobilisation by a semirigid neck collar is easier using the Disposcope endoscope (DE), a new video laryngoscope, than with the Macintosh laryngoscope (ML).MethodsSixty-eight medical interns who participated in a training programme for endotracheal intubation using the DE and ML were recruited to the randomised crossover trial 1 week after completing the training programme. In the trial, they used both the DE and the ML to perform intubation on a manikin wearing a semirigid neck collar. The time required to view the vocal cords and to complete intubation, successful endotracheal intubation, modified Cormack–Lehane classification (CL grade) and dental injury were recorded and analysed.ResultsThe mean (SD) time to view the vocal cords was significantly shorter with the DE than with the ML (10.0 (7.0) vs 20.8 (18.9) s; p<0.0001). There were higher rates of CL grades 1 and 2a (69.1% and 22.1%) using the DE than with the ML (10.3% and 14.7%). All 68 participants had a higher rate of successful endotracheal intubation using the DE than using the ML (68 (100%) vs 47 (69.1%); p<0.0001). It took less time to complete endotracheal intubation with the DE than with the ML (p<0.0001).ConclusionsIn patients with cervical spine immobilisation by a semirigid neck collar, the DE may be a more effective device for endotracheal intubation than the ML.