bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monoclonal Antibodies of a Diverse Isotype Induced by an O-Antigen Glycoconjugate Vaccine Mediate
In Vitro
and
In Vivo
Killing of African Invasive Nontyphoidal Salmonella
Authors: Goh Yun Shan , Clare Simon , Micoli Francesca , Saul Allan , Mastroeni Pietro , MacLennan Calman A. 
Published: July 2015

ABSTRACT

Nontyphoidal
Salmonella
(NTS), particularly
Salmonella enterica
serovars Typhimurium and Enteritidis, is responsible for a major global burden of invasive disease with high associated case-fatality rates. We recently reported the development of a candidate O-antigen–CRM
197
glycoconjugate vaccine against
S.
Typhimurium. Here, using a panel of mouse monoclonal antibodies generated by the vaccine, we examined the relative efficiency of different antibody isotypes specific for the O:4 antigen of
S
. Typhimurium to effect
in vitro
and
in vivo
killing of the invasive African
S
. Typhimurium strain D23580. All O:4-specific antibody isotypes could mediate cell-free killing and phagocytosis of
S
. Typhimurium by mouse blood cells. Opsonization of
Salmonella
with O:4-specific IgA, IgG1, IgG2a, and IgG2b, but not IgM, resulted in cell-dependent bacterial killing. At high concentrations, O:4-specific antibodies inhibited both cell-free complement-mediated and cell-dependent opsonophagocytic killing of
S
. Typhimurium
in vitro
. Using passive immunization in mice, the O:4-specific antibodies provided
in vivo
functional activity by decreasing the bacterial load in the blood and tissues, with IgG2a and IgG2b being the most effective isotypes. In conclusion, an O-antigen–CRM
197
glycoconjugate vaccine can induce O-antigen-specific antibodies of different isotypes that exert
in vitro
and
in vivo
killing of
S
. Typhimurium.
Proteomic Identification of
saeRS
-Dependent Targets Critical for Protective Humoral Immunity against Staphylococcus aureus Skin Infection
Authors: Zhao Fan , Cheng Brian L. , Boyle-Vavra Susan , Alegre Maria-Luisa , Daum Robert S. , Chong Anita S. , Montgomery Christopher P. 
Published: July 2015

ABSTRACT

Recurrent
Staphylococcus aureus
skin and soft tissue infections (SSTIs) are common despite detectable antibody responses, leading to the belief that the immune response elicited by these infections is not protective. We recently reported that
S. aureus
USA300 SSTI elicits antibodies that protect against recurrent SSTI in BALB/c but not C57BL/6 mice, and in this study, we aimed to uncover the specificity of the protective antibodies. Using a proteomic approach, we found that
S. aureus
SSTI elicited broad polyclonal antibody responses in both BALB/c and C57BL/6 mice and identified 10
S. aureus
antigens against which antibody levels were significantly higher in immune BALB/c serum. Four of the 10 antigens identified are regulated by the
saeRS
operon, suggesting a dominant role for
saeRS
in protection. Indeed, infection with USA300Δ
sae
failed to protect against secondary SSTI with USA300, despite eliciting a strong polyclonal antibody response against antigens whose expression is not regulated by
saeRS
. Moreover, the antibody repertoire after infection with USA300Δ
sae
lacked antibodies specific for 10
saeRS
-regulated antigens, suggesting that all or a subset of these antigens are necessary to elicit protective immunity. Infection with USA300Δ
hla
elicited modest protection against secondary SSTI, and complementation of USA300Δ
sae
with
hla
restored protection but incompletely. Together, these findings support a role for both Hla and other
saeRS
-regulated antigens in eliciting protection and suggest that host differences in immune responses to
saeRS
-regulated antigens may determine whether
S. aureus
infection elicits protective or nonprotective immunity against recurrent infection.
Transcriptional Regulation by the Short-Chain Fatty Acyl Coenzyme A Regulator (ScfR) PccR Controls Propionyl Coenzyme A Assimilation by Rhodobacter sphaeroides
Authors: Carter Michael S. , Alber Birgit E. 
Published: July 2015

ABSTRACT

Propionyl coenzyme A (propionyl-CoA) assimilation by
Rhodobacter sphaeroides
proceeds via the methylmalonyl-CoA pathway. The activity of the key enzyme of the pathway, propionyl-CoA carboxylase (PCC), was upregulated 20-fold during growth with propionate compared to growth with succinate. Because propionyl-CoA is an intermediate in acetyl-CoA assimilation via the ethylmalonyl-CoA pathway, acetate growth also requires the methylmalonyl-CoA pathway. PCC activities were upregulated 8-fold in extracts of acetate-grown cells compared to extracts of succinate-grown cells. The upregulation of PCC activities during growth with propionate or acetate corresponded to increased expression of the
pccB
gene, which encodes a subunit of PCC. PccR (RSP_2186) was identified to be a transcriptional regulator required for the upregulation of
pccB
transcript levels and, consequently, PCC activity: growth substrate-dependent regulation was lost when
pccR
was inactivated by an in-frame deletion. In the
pccR
mutant,
lacZ
expression from a 215-bp plasmid-borne
pccB
upstream fragment including 27 bp of the
pccB
coding region was also deregulated. A loss of regulation as a result of mutations in the conserved motifs TTTGCAAA-X
4
-TTTGCAAA in the presence of PccR allowed the prediction of a possible operator site. PccR, together with homologs from other organisms, formed a distinct clade within the family of
s
hort-
c
hain
f
atty acyl coenzyme A
r
egulators (ScfRs) defined here. Some members from other clades within the ScfR family have previously been shown to be involved in regulating acetyl-CoA assimilation by the glyoxylate bypass (RamB) or propionyl-CoA assimilation by the methylcitrate cycle (MccR).

IMPORTANCE
Short-chain acyl-CoAs are intermediates in essential biosynthetic and degradative pathways. The regulation of their accumulation is crucial for appropriate cellular function. This work identifies a regulator (PccR) that prevents the accumulation of propionyl-CoA by controlling expression of the gene encoding propionyl-CoA carboxylase, which is responsible for propionyl-CoA consumption by
Rhodobacter sphaeroides
. Many other
Proteobacteria
and
Actinomycetales
contain one or several PccR homologs that group into distinct clades on the basis of the pathway of acyl-CoA metabolism that they control. Furthermore, an upstream analysis of genes encoding PccR homologs allows the prediction of conserved binding motifs for these regulators. Overall, this study evaluates a single regulator of propionyl-CoA assimilation while expanding the knowledge of the regulation of short-chain acyl-CoAs in many bacterial species.
Coordination of Synthesis and Assembly of a Modular Membrane-Associated [NiFe]-Hydrogenase Is Determined by Cleavage of the C-Terminal Peptide
Authors: Thomas Claudia , Muhr Enrico , Sawers R. Gary 
Published: July 2015

ABSTRACT

During biosynthesis of [NiFe]-hydrogenase 2 (Hyd-2) of
Escherichia coli
, a 15-amino-acid C-terminal peptide is cleaved from the catalytic large subunit precursor, pro-HybC. This peptide is removed only after NiFe(CN)
2
CO cofactor insertion by the Hyp accessory protein machinery has been completed, suggesting that it has a regulatory function during enzyme maturation. We show here that in
hyp
mutants that fail to synthesize and insert the NiFe cofactor, and therefore retain the peptide, the Tat (twin-arginine translocon) signal peptide on the small subunit HybO is not removed and the subunit is degraded. In a mutant lacking the large subunit, the Tat signal peptide was also not removed from pre-HybO, indicating that the mature large subunit must actively engage the small subunit to elicit Tat transport. We validated the proposed regulatory role of the C-terminal peptide in controlling enzyme assembly by genetically removing it from the precursor of HybC, which allowed assembly and Tat-dependent membrane association of a HybC-HybO heterodimer lacking the NiFe(CN)
2
CO cofactor. Finally, genetic transfer of the C-terminal peptide from pro-HyaB, the large subunit of Hyd-1, onto HybC did not influence its dependence on the accessory protein HybG, a HypC paralog, or the specific protease HybD. This indicates that the C-terminal peptide
per se
is not required for interaction with the Hyp machinery but rather suggests a role of the peptide in maintaining a conformation of the protein suitable for cofactor insertion. Together, our results demonstrate that the C-terminal peptide on the catalytic subunit controls biosynthesis, assembly, and membrane association of Hyd-2.

IMPORTANCE
[NiFe]-hydrogenases are multisubunit enzymes with a catalytic subunit containing a NiFe(CN)
2
CO cofactor. Results of previous studies suggested that after synthesis and insertion of the cofactor by the Hyp accessory proteins, this large subunit changes conformation upon proteolytic removal of a short peptide from its C terminus. We show that removal of this peptide is necessary to allow the cleavage of the Tat signal peptide from the small subunit with concomitant membrane association of the heterodimer to occur. Genetic removal of the C-terminal peptide from the large subunit allowed productive interaction with the small subunit and Tat-dependent membrane insertion of a NiFe cofactor-free enzyme. Results based on swapping of C-terminal peptides between hydrogenases suggest that this peptide governs enzyme assembly via a conformational switch.
Aconitase Functions as a Pleiotropic Posttranscriptional Regulator in Helicobacter pylori
Authors: Austin Crystal M. , Wang Ge , Maier Robert J. 
Published: July 2015

ABSTRACT

Posttranscriptional regulation in bacteria has increasingly become recognized as playing a major role in response to environmental stimuli. Aconitase is a bifunctional protein that not only acts enzymatically but also can be a posttranscriptional regulator. To investigate protein expression regulated by
Helicobacter pylori
AcnB in response to oxidative stress, a global proteomics study was conducted wherein the Δ
acnB
strain was compared to the parent strain when both strains were O
2
stressed. Many proteins, including some involved in urease activity, in combating oxidative stress, and in motility, were expressed at a significantly lower level in the Δ
acnB
strain. A bioinformatics prediction tool was used to identify putative targets for aconitase-mediated regulation, and electrophoretic mobility shift assays demonstrated that apo-AcnB is able to bind to RNA transcripts of
hpn
(encoding a nickel-sequestering protein),
ahpC
(encoding alkyl hydroperoxide reductase), and
flgR
(encoding flagellum response regulator). Compared to the wild type (WT), the Δ
acnB
strain had decreased activities of the nickel-containing enzymes urease and hydrogenase, and this could be correlated with lower total nickel levels within Δ
acnB
cells. Binding of apo-AcnB to the
hpn
5′ untranslated region (UTR) may inhibit the expression of Hpn. In agreement with the finding that AcnB regulates the expression of antioxidant proteins such as AhpC, Δ
acnB
cells displayed oxidative-stress-sensitive phenotypes. The Δ
acnB
strain has a lesser motility ability than the WT strain, which can likely be explained by the functions of AcnB on the FlgRS-RpoN-FlgE regulatory cascade. Collectively, our results suggest a global role for aconitase as a posttranscriptional regulator in this gastric pathogen.

IMPORTANCE
Bacterial survival depends on the ability of the cell to sense and respond to a variety of environmental changes. For
Helicobacter pylori
, responding to environmental stimuli within the gastric niche is essential for persistence and host colonization. However, there is much to be learned about the regulatory mechanisms that
H. pylori
employs to orchestrate its response to different stimuli. In this study, we explore the role of aconitase, a bifunctional protein that has been found to act as a posttranscriptional regulator in several other bacteria. Our results shed light on the magnitude of aconitase-mediated regulation in
H. pylori
, and we propose that aconitase acts as a global regulator of key genes involved in virulence.
CD38 in Hairy Cell Leukemia Is a Marker of Poor Prognosis and a New Target for Therapy
Authors: Poret Nicolas , Fu Qiangwei , Guihard Soizic , Cheok Meyling , Miller Katie , Zeng Gordon , Quesnel Bruno , Troussard Xavier , Galiègue-Zouitina Sylvie , Shelley Carl Simon 
Published: July 2015

AbstractHairy cell leukemia (HCL) is characterized by underexpression of the intracellular signaling molecule RhoH. Reconstitution of RhoH expression limits HCL pathogenesis in a mouse model, indicating this could represent a new therapeutic strategy. However, while RhoH reconstitution is theoretically possible as a therapy, it is technically immensely challenging as an appropriately functional RhoH protein needs to be specifically targeted. Because of this problem, we sought to identify druggable proteins on the HCL surface that were dependent upon RhoH underexpression. One such protein was identified as CD38. Analysis of 51 HCL patients demonstrated that 18 were CD38-positive. Interrogation of the clinical record of 23 relapsed HCL patients demonstrated those that were CD38-positive had a mean time to salvage therapy 71 months shorter than patients who were CD38-negative. Knockout of the CD38 gene in HCL cells increased apoptosis, inhibited adherence to endothelial monolayers, and compromised ability to produce tumors in vivo. Furthermore, an anti-CD38 antibody proved effective against pre-existing HCL tumors. Taken together, our data indicate that CD38 expression in HCL drives poor prognosis by promoting survival and heterotypic adhesion. Our data also indicate that CD38-positive HCL patients might benefit from treatments based on CD38 targeting. Cancer Res; 75(18); 3902–11. ©2015 AACR.
Hepatitis C Virus Seroprevalence in Mongolian Women Assessed by a Novel Multiplex Antibody Detection Assay
Authors: Dondog Bolormaa , Schnitzler Paul , Michael Kristina M. , Clifford Gary , Franceschi Silvia , Pawlita Michael , Waterboer Tim 
Published: July 2015

Abstract
Background: Hepatitis C virus (HCV) infection causes hepatocellular carcinoma and is an important cause of mortality in both industrialized and developing countries. We developed a single-step high-throughput multiplex serology assay for HCV antibody detection and determined HCV prevalence in a highly endemic country.
Methods: Five proteins (Core, NS3, NS4A, NS5A, NS5B) each from the three most common subtypes of HCV (1a, 1b, 2a) were recombinantly expressed and used as antigens in a multiplexed antibody detection assay. Multiplex HCV serology was validated with 432 reference sera whose HCV status was established by commercial ELISA, Western blot, and RNA assays. HCV antibodies were determined in 1,023 sera representative for the adult female population of Mongolia.
Results: In reference sera, detection of HCV (mostly Core and NS3) antibodies by multiplex serology showed 100% sensitivity and 99.6% specificity, and was in very good agreement with the commercial diagnostic assays (kappa, 0.96; 95% confidence interval, 0.92–0.99). The role of antibodies to NS4 and NS5 remains to be evaluated. In Mongolia, overall HCV antibody prevalence was 18.9% (17.8% when age-standardized to the world population). HCV seroprevalence increased with age from 10% in women &lt;30 years to 32% in women ≥50 years, but was not related to sexual risk factors.
Conclusions: The single-step high-throughput multiplex HCV serology assay performs similarly to conventional HCV antibody screening followed by secondary confirmation assays. A very high HCV seroprevalence was confirmed across all socio-economic groups in the female population of Mongolia.
Impact: Multiplex HCV serology facilitates large seroepidemiologic studies of HCV infection. Cancer Epidemiol Biomarkers Prev; 24(9); 1360–5. ©2015 AACR.
Robust In Vitro and In Vivo Neutralization against Multiple High-Risk HPV Types Induced by a Thermostable Thioredoxin-L2 Vaccine
Authors: Seitz Hanna , Ribeiro-Müller Lis , Canali Elena , Bolchi Angelo , Tommasino Massimo , Ottonello Simone , Müller Martin 
Published: July 2015

Abstract
Current prophylactic virus-like particle (VLP) human papillomavirus (HPV) vaccines are based on the L1 major capsid protein and provide robust but virus type-restricted protection. Moreover, VLP vaccines have a high production cost, require cold-chain storage, and are thus not readily implementable in developing countries, which endure 85% of the cervical cancer–related death burden worldwide. In contrast with L1, immunization with minor capsid protein L2 elicits broad cross-neutralization, and we previously showed that insertion of a peptide spanning amino acids 20–38 of L2 into bacterial thioredoxin (Trx) greatly enhances its immunogenicity. Building on this finding, we use, here, four different neutralization assays to demonstrate that low doses of a trivalent Trx-L2 vaccine, incorporating L2(20–38) epitopes from HPV16, HPV31 and HPV51, and formulated in a human-compatible adjuvant, induce broadly protective responses. Specifically, we show that this vaccine, which uses a far-divergent archaebacterial thioredoxin as scaffold and is amenable to an easy one-step thermal purification, induces robust cross-neutralization against 12 of the 13 known oncogenic HPV types. Immune performance measured with two different in vitro neutralization assays was corroborated by the results of mouse cervico-vaginal challenge and passive transfer experiments indicating robust cross-protection also in vivo. Altogether, our results attest to the potential of Trx-L2 as a thermostable second-generation HPV vaccine particularly well suited for low-resource countries. Cancer Prev Res; 8(10); 932–41. ©2015 AACR.
Caval Penetration by Inferior Vena Cava Filters
Authors: Jia Zhongzhi , Wu Alex , Tam Mathew , Spain James , McKinney J. Mark , Wang Weiping 
Published: July 2015

Background—
Limited penetration into the caval wall is an important securing mechanism for inferior vena cava (IVC) filters; however, caval penetration can also cause unintentional complications. The aim of this study was to assess the incidence, severity, clinical consequences, and management of filter penetration across a range of commercially available IVC filters.

Methods and Results—
The MEDLINE database was searched for all studies (1970–2014) related to IVC filters. A total of 88 clinical studies and 112 case reports qualified for analysis; these studies included 9002 patients and 15 types of IVC filters. Overall, penetration was reported in 19% of patients (1699 of 9002), and 19% of those penetrations (322 of 1699) showed evidence of organ/structure involvement. Among patients with penetration, 8% were symptomatic, 45% were asymptomatic, and 47% had unknown symptomatology. The most frequently reported symptom was pain (77%, 108 of 140). Major complications were reported in 83 patients (5%). These complications required interventions including surgical removal of the IVC filter (n=63), endovascular stent placement or embolization (n=11), endovascular retrieval of the permanent filter (n=4), and percutaneous nephrostomy or ureteral stent placement (n=3). Complications led to death in 2 patients. A total of 87% of patients (127 of 146) underwent premature filter retrieval or interventions for underlying symptoms or penetration-related complications.

Conclusions—
Caval penetration is a frequent but clinically underrecognized complication of IVC filter placement. Symptomatic patients accounted for nearly 1/10th of all penetrations; most of these cases had organ/structure involvement. Interventions with endovascular retrieval and surgery were required in most of these symptomatic patients.
New York State: Comparison of Treatment Outcomes for Unruptured Cerebral Aneurysms Using an Instrumental Variable Analysis
Authors: Bekelis Kimon , Missios Symeon , Coy Shannon , Singer Robert J. , MacKenzie Todd A. 
Published: July 2015

Background
There is wide regional variation in the predominant treatment for unruptured cerebral aneurysms. We investigated the association of elective surgical clipping and endovascular coiling with mortality, readmission rate, length of stay, and discharge to rehabilitation.

Methods and Results

We performed a cohort study involving patients with unruptured cerebral aneurysms, who underwent surgical clipping or endovascular coiling from 2009 to 2013 and were registered in the Statewide Planning and Research Cooperative System database. An instrumental variable analysis was used to investigate the association of treatment technique with outcomes. Of the 4643 patients undergoing treatment, 3190 (68.7%) underwent coiling, and 1453 (31.3%) underwent clipping. Using an instrumental variable analysis, we did not identify a difference in inpatient mortality (marginal effect, 0.13; 95%
CI
, −0.30, 0.57), or the rate of 30‐day readmission (marginal effect, −1.84; 95%
CI
−4.06, −0.37) between the 2 treatment techniques for patients with unruptured cerebral aneurysms. Clipping was associated with a higher rate of discharge to rehabilitation (marginal effect, 2.31; 95%
CI
0.21, 4.41), and longer length of stay (β, 2.01; 95%
CI
0.85, 3.04). In sensitivity analysis, mixed‐effect regression, and propensity score, adjusted regression models demonstrated identical results.

Conclusions
Using a comprehensive all‐payer cohort of patients in New York State with unruptured cerebral aneurysms, we did not identify an association of treatment method with mortality or 30‐day readmission. Clipping was associated with a higher rate of discharge to rehabilitation and longer length of stay.
The Predictability of Rainfall over the Greater Horn of Africa. Part II: Prediction of Monthly Rainfall during the Long Rains
Authors: Nicholson Sharon E. 
Published: July 2015

Abstract
Seasonal prediction of the boreal spring rains in the Greater Horn of Africa has been notoriously challenging. Predictability is markedly lower than during the autumnal rainy season. Part I of this article explored predictability at the seasonal scale, using multiple linear regression. However, the three months of the boreal spring season are clearly different climatologically and with respect to the prevailing atmospheric circulation and controls on interannual variability. For that reason, the current study follows up on Part I by examining the predictability of the three months individually. The current study utilizes 1- and 2-month lead times and the results are evaluated via cross validation. This approach provided improved skill for April and May in the equatorial rainfall region, but not for March in this region and not for the region with predominantly summer rainfall. Overall, the best predictors are shown to be atmospheric variables, most often zonal and meridional wind. Sea surface temperatures and sea level pressure provided little predictive skill.