bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increase in perfused boundary region of endothelial glycocalyx is associated with higher prevalence of ischemic heart disease and lesions of microcirculation and vascular wall
Authors: Gorshkov Alexander Y. , Klimushina Marina V. , Boytsov Sergei A. , Kots Alexander Y. , Gumanova Nadezhda G. 
Published: April 2018

AbstractObjectivePBR characterizes penetration of red blood cells inside glycocalyx and its thickness can have profound impact on microcirculation and other vascular parameters. The goal of our study was to reliably quantify PBR and assess its potential use as a new marker of cardiovascular pathology.MethodsThe study included 208 patients (123 men and 85 women from 40 to 65 years of age) with various grades of cardiovascular SCORE risk index and IHD. PBR was quantified by sidestream dark field capillaroscopy with green light excitation. Cutaneous microcirculation was evaluated with laser Doppler fluorometry.ResultsElevated PBR values over 2 mm were associated with morphological and functional lesions of arterial wall and microcirculation and lowered levels of ApoA1 lipoprotein. Moreover, elevated PBR values were associated with 2.07‐fold increase in prevalence of cerebral atherosclerosis (P = .015) and 2.42‐fold increase in prevalence of IHD (P = .024). Increase in PBR was associated with elevated systolic blood pressure.ConclusionsThus, PBR can be considered a new highly reproducible and promising marker candidate for non‐invasive diagnostics of IHD and cerebral atherosclerosis suggesting important role of microcirculation in development and progression of cardiovascular diseases.
Descriptions of two new species of flea of the genus Plocopsylla in northwestern Argentina
Authors: López‐Berrizbeitia M. F. , Sanchez J. , Barquez R. M. , Díaz M. M. 
Published: April 2018

AbstractTwo new species of flea of the genus Plocopsylla, subgenus Plocopsylla, (Siphonaptera: Stephanocircidae) collected from sigmodontine rodents in northwestern Argentina are described and a key to identification of species of the genus Plocopsylla, subgenus Plocopsylla, in Argentina is presented. Plocopsylla (P.) inti is cited for the first time in Argentina, extending its distribution ∼ 970 km further south than previously documented. New locality data and flea–host associations are recorded. The contributions of this study are relevant because they increase knowledge of the diversity of flea fauna in northwestern Argentina bordering a plague endemic area and will be useful in the implementation of plague control management plans in the future.
Biocrust‐forming mosses mitigate the impact of aridity on soil microbial communities in drylands: observational evidence from three continents
Authors: Delgado‐Baquerizo Manuel , Maestre Fernando T. , Eldridge David J. , Bowker Matthew A. , Jeffries Thomas C. , Singh Brajesh K. 
Published: April 2018

Summary

Recent research indicates that increased aridity linked to climate change will reduce the diversity of soil microbial communities and shift their community composition in drylands, Earth's largest biome. However, we lack both a theoretical framework and solid empirical evidence of how important biotic components from drylands, such as biocrust‐forming mosses, will regulate the responses of microbial communities to expected increases in aridity with climate change.

Here we report results from a cross‐continental (North America, Europe and Australia) survey of 39 locations from arid to humid ecosystems, where we evaluated how biocrust‐forming mosses regulate the relationship between aridity and the community composition and diversity of soil bacteria and fungi in dryland ecosystems.

Increasing aridity was negatively related to the richness of fungi, and either positively or negatively related to the relative abundance of selected microbial phyla, when biocrust‐forming mosses were absent. Conversely, we found an overall lack of relationship between aridity and the relative abundance and richness of microbial communities under biocrust‐forming mosses.

Our results suggest that biocrust‐forming mosses mitigate the impact of aridity on the community composition of globally distributed microbial taxa, and the diversity of fungi. They emphasize the importance of maintaining biocrusts as a sanctuary for soil microbes in drylands.
Roux‐en‐Y enterolith leading to obstruction and ischemic necrosis after pediatric orthotopic liver transplantation
Authors: Quillin Ralph C. , Bongu Advaith , Kasper Vania , Vittorio Jennifer M. , Martinez Mercedes , Lobritto Steven J. , Griesemer Adam D. , Guarrera James V. 
Published: April 2018

AbstractBiliary complications are a common cause of morbidity after liver transplantation, with biliary stone formation being a known occurrence generally upstream of a stricture. A 12‐year‐old boy, who underwent an orthotopic liver transplantation at 11 months of age for biliary atresia, presented acutely with fever and abdominal pain. Cross‐sectional imaging revealed Roux‐en‐Y limb dilatation and thickening. He was explored and was found to have an ischemic Roux limb secondary to an obstructing enterolith. A segmental bowel resection and revision of his hepaticojejunostomy was performed. While rare, biliary enteroliths may present as either a bowel obstruction or cholangitis and should be considered in the differential diagnosis of a patient following biliary reconstruction. Additionally, anatomic etiologies should be considered and potentially surgically corrected.
Arabidopsis thaliana expressing PbBSMT, a gene encoding a SABATH‐type methyltransferase from the plant pathogenic protist Plasmodiophora brassicae, show leaf chlorosis and altered host susceptibility
Authors: Bulman S. , Richter F. , Marschollek S. , Benade F. , Jülke S. , Ludwig‐Müller J. 
Published: April 2018

Abstract

The plant pathogenic protist Plasmodiophora brassicae causes clubroot disease of Brassicaceae. This biotrophic organism can down‐regulate plant defence responses. The previously characterised P. brassicae PbBSMT methyltransferase has substrate specificity for salicylic, benzoic and anthranilic acids. We therefore propose a role for the methylation of SA in attenuating plant defence response in infected roots as a novel strategy for intracellular parasitism.

We overexpressed PbBSMT under the control of an inducible promoter in Arabidopsis thaliana and performed physiological, molecular and phytopathological analyses with the transgenic plants under control and induced conditions in comparison to the wild type.

Upon induction, transcription of PbBSMT was associated with: (1) strong leaf phenotypes from anthocyanin accumulation and chlorosis followed by browning; (2) increased plant susceptibility after infection with P. brassicae that was manifested as more yellow leaves and reduced growth of upper plant parts; and (3) induced transgenic plants were not able to support large galls and had a brownish appearance of some clubs. Microarray data indicated that chlorophyll loss was accompanied by reduced transcription of genes involved in photosynthesis, while genes encoding glucose metabolism, mitochondrial functions and cell wall synthesis were up‐regulated.

Our results indicate a role for PbBSMT in attenuation of host defence responses in the roots by metabolising a plant defence signal.
Epidemiological, clinical and mechanistic perspectives of tuberculosis in older people
Authors: Yew Wing W. , Yoshiyama Takashi , Leung Chi C. , Chan Denise P. 
Published: April 2018

ABSTRACTWith the ageing population globally, tuberculosis (TB) in older people becomes a major clinical and public health challenge. In many Asian countries, especially those located in the eastern and southeastern parts of the continent, geriatric TB is a significant problem. TB in the older patients is more difficult to diagnose in the early course of disease, and has poorer treatment outcomes, largely as increased failure and death. More drug‐induced adverse reactions are also experienced by this population during TB therapy. Oxidative stress and mitochondrial dysfunction are now well recognized to be associated with the ageing process, and it is likely that the cellular and molecular perturbations interact inextricably with the immunological dysfunction biophysiologically inherent to ageing. These underlying mechanistic bases putatively contribute to the development of TB in the geriatric population and worsen the disease outcomes, especially when the TB is compounded by co‐morbid conditions such as smoking and diabetes mellitus. Unravelling these mechanisms further would yield knowledge that might potentially help to prevent reactivated TB in older people, and also to better manage the established disease with drug regimens and other new therapeutic strategies. In addition, addressing the social elements associated with geriatric TB is also imperative in the relief of individual patient suffering and improvement of overall disease control.
PEMBANGUNAN KAEDAH PENCIRIAN SIFAT MEKANIKAL BAHAN POLIMER MENGGUNAKAN ANALISIS I-KAZ 4D/DEVELOPMENT OF POLYMER MECHANICAL PROPERTIES CHARACTERISTICS USING I-KAZ 4D ANALYSIS METHOD
Authors: Ramli Mohd Irman , Nuawi Mohd. Zaki , Mohammad Rasani Mohammad Rasidi , Abdullah Shahrum , Ahmad Muhamad Arif Fadli , Abdullah Muhammad Fazrin 
Published: April 2018

This study was undertaken to develop an alternative method based on signal analysis known as I-kaz 4D or I-kaz 4 channels. The aim was to characterize several mechanical properties including Poisson Ratio (PR), Vickers Hardness (VH), Yield Strength (YS), Tensile Strength (TS), Compression Strength (CS) and Fatigue Strength (FS). Specimens used are Polyoxymethylene (POM), Polyvinylchloride (PVC) and Blue Nylon MC (MC Blue). Round bar shape specimens were impacted by steel ball from different heights, 20 cm to 40 cm. This test was conducted at semi-anechoic room and follow ASTM E1876 standard accordingly. 4 accelerometer sensors were placed on the specimen surface to capture vibration signal produced by ball impact. Transient signals which generated from ball impact were analysed using Matlab software based on mathematical model I-kaz 4D. As a result, a correlation was found between I-kaz linear coefficient and material mechanical properties. However the errors are within acceptable range for all specimens used. It was found that average errors for Poisson Ratio = 0.69%, Vickers Hardness = 2.12%, Yield Strength = 3.20%, Tensile Strength = 2.43%, Compression Strength = 2.75% and Fatigue Strength = 2.02%. It has potentiality to be used for further analysis of the respective materials.
COMBUSTION CHARACTERISTICS OF RICE BRAN OIL BIODIESEL IN AN OIL BURNER
Authors: Mohd Jaafar Mohammad Nazri , Safiullah Safiullah 
Published: April 2018

The concept of biodiesel as an alternative fuel is not an overnight thought, but the escalating prices, pungent emission gases and non-ecological behavior of fossil fuels has constrained the researchers to take the necessary steps. Biodiesels which are renewable in nature and having environmental friendly attribute have shown the potential to be the perfect replacement for the diesel fuels. Similarly, this study demonstrates the characteristics of Rice Bran Oil (RBO) which can be used as a latent substitute for diesel products. RBO is a vegetable oil, which is extracted from the rice bran (by-product of rice grain). Since rice is the staple diet for more than half of the world population, the quantity of RBO that can be extracted is enormous. In this study, the converted RBO into biodiesel (RBOBD) was blended with diesel to produce B5, B15 and B25 to determine physical properties and combustion performance. Owing to highly packed molecules of RBOBD, the properties such as density, kinematic viscosity and surface tension are higher in RBOBD and its blends than diesel. In contrast, the calorific value is lower. In the combustion test, the highest wall temperature is achieved at stoichiometric fuel mixture, while among the fuels, the wall temperature decreases as the biodiesel proportion increases in the blends. Moreover, in B25, emissions such as CO and SO2 are 68% and 50% lower than that of diesel respectively. However, due to the additional oxygen present in the biodiesel structure, NOx emission of B25 is 15.67% higher than diesel.
Use of External Quality Control Material for HIV-1 RNA Testing To Assess the Comparability of Data Generated in Separate Laboratories and the Stability of HIV-1 RNA in Samples after Prolonged Storage
Authors: Jennings Cheryl , Wager Carrie G. , Scianna Salvatore R. , Zaccaro Daniel J. , Couzens Amy , Mellors John W. , Coombs Robert W. , Bremer James W. 
Published: April 2018

ABSTRACT

The National Institute of Allergy and Infectious Diseases (NIAID) AIDS Clinical Trials Group (ACTG) stores specimens from its clinical trials in a biorepository and permits the use of these specimens for nonprotocol exploratory studies, once the studies for the original protocol are concluded. We sought to assess the comparability of the data generated from real-time HIV-1 RNA testing during two clinical trials with the data generated from the retesting of different aliquots of the same samples after years of storage at −80°C. Overall, there was 92% agreement in the data generated for 1,570 paired samples (kappa statistic = 0.757; 95% confidence interval [CI], 0.716 to 0.797), where samples were tested in one laboratory using the microwell plate (MWP) version of the Roche HIV-1 Monitor test within 1 to 37 days of collection and retested in another laboratory using the Cobas version of the assay after a median of 6.7 years of storage (range, 5.7 to 8.6 years). Historical external quality control data submitted to the NIAID Virology Quality Assurance program (VQA) by client laboratories using the same two versions of the Monitor assay were used to differentiate between systematic differences in the assays to evaluate the stability of HIV-1 RNA in the stored samples. No significant loss of RNA was noted in samples containing either a low concentration (<50 copies/ml) or a high concentration (≥50 copies/ml) of HIV-1 RNA (
P
= 0.10 and
P
= 0.90, respectively) regardless of the time in storage. These data confirm the quality of the plasma samples in the ACTG biorepository following long-term storage.
Chlamydia trachomatis dapF
Encodes a Bifunctional Enzyme Capable of Both
d
-Glutamate Racemase and Diaminopimelate Epimerase Activities
Authors: Liechti George , Singh Raghuveer , Rossi Patricia L. , Gray Miranda D. , Adams Nancy E. , Maurelli Anthony T. 
Published: April 2018

ABSTRACT

Peptidoglycan is a sugar/amino acid polymer unique to bacteria and essential for division and cell shape maintenance. The
d
-amino acids that make up its cross-linked stem peptides are not abundant in nature and must be synthesized by bacteria
de novo
.
d
-Glutamate is present at the second position of the pentapeptide stem and is strictly conserved in all bacterial species. In Gram-negative bacteria,
d
-glutamate is generated via the racemization of
l
-glutamate by glutamate racemase (MurI).
Chlamydia trachomatis
is the leading cause of infectious blindness and sexually transmitted bacterial infections worldwide. While its genome encodes a majority of the enzymes involved in peptidoglycan synthesis, no
murI
homologue has ever been annotated. Recent studies have revealed the presence of peptidoglycan in
C. trachomatis
and confirmed that its pentapeptide includes
d
-glutamate. In this study, we show that
C. trachomatis
synthesizes
d
-glutamate by utilizing a novel, bifunctional homologue of diaminopimelate epimerase (DapF). DapF catalyzes the final step in the synthesis of
meso
-diaminopimelate, another amino acid unique to peptidoglycan. Genetic complementation of an
Escherichia coli murI
mutant demonstrated that
Chlamydia
DapF can generate
d
-glutamate. Biochemical analysis showed robust activity, but unlike canonical glutamate racemases, activity was dependent on the cofactor pyridoxal phosphate. Genetic complementation, enzymatic characterization, and bioinformatic analyses indicate that chlamydial DapF shares characteristics with other promiscuous/primordial enzymes, presenting a potential mechanism for
d
-glutamate synthesis not only in
Chlamydia
but also numerous other genera within the
Planctomycetes
-
Verrucomicrobiae
-
Chlamydiae
superphylum that lack recognized glutamate racemases.

IMPORTANCE
Here we describe one of the last remaining “missing” steps in peptidoglycan synthesis in pathogenic
Chlamydia
species, the synthesis of
d
-glutamate. We have determined that the diaminopimelate epimerase (DapF) encoded by
Chlamydia trachomatis
is capable of carrying out both the epimerization of DAP and the pyridoxal phosphate-dependent racemization of glutamate. Enzyme promiscuity is thought to be the hallmark of early microbial life on this planet, and there is currently an active debate as to whether “moonlighting enzymes” represent primordial evolutionary relics or are a product of more recent reductionist evolutionary pressures. Given the large number of
Chlamydia
species (as well as members of the
Planctomycetes
-
Verrucomicrobiae
-
Chlamydiae
superphylum) that possess DapF but lack homologues of MurI, it is likely that DapF is a primordial isomerase that functions as both racemase and epimerase in these organisms, suggesting that specialized
d
-glutamate racemase enzymes never evolved in these microbes.
Conservation and Divergence in the
Candida
Species Biofilm Matrix Mannan-Glucan Complex Structure, Function, and Genetic Control
Authors: Dominguez Eddie , Zarnowski Robert , Sanchez Hiram , Covelli Antonio S. , Westler William M. , Azadi Parastoo , Nett Jeniel , Mitchell Aaron P. , Andes David R. 
Published: April 2018

ABSTRACT

Candida
biofilms resist the effects of available antifungal therapies. Prior studies with
Candida albicans
biofilms show that an extracellular matrix mannan-glucan complex (MGCx) contributes to antifungal sequestration, leading to drug resistance. Here we implement biochemical, pharmacological, and genetic approaches to explore a similar mechanism of resistance for the three most common clinically encountered non-
albicans
Candida
species (NAC). Our findings reveal that each
Candida
species biofilm synthesizes a mannan-glucan complex and that the antifungal-protective function of this complex is conserved. Structural similarities extended primarily to the polysaccharide backbone (α-1,6-mannan and β-1,6-glucan). Surprisingly, biochemical analysis uncovered stark differences in the branching side chains of the MGCx among the species. Consistent with the structural analysis, similarities in the genetic control of MGCx production for each
Candida
species also appeared limited to the synthesis of the polysaccharide backbone. Each species appears to employ a unique subset of modification enzymes for MGCx synthesis, likely accounting for the observed side chain diversity. Our results argue for the conservation of matrix function among
Candida
spp. While biogenesis is preserved at the level of the mannan-glucan complex backbone, divergence emerges for construction of branching side chains. Thus, the MGCx backbone represents an ideal drug target for effective pan-
Candida
species biofilm therapy.

IMPORTANCE
Candida
species, the most common fungal pathogens, frequently grow as a biofilm. These adherent communities tolerate extremely high concentrations of antifungal agents, due in large part, to a protective extracellular matrix. The present studies define the structural, functional, and genetic similarities and differences in the biofilm matrix from the four most common
Candida
species. Each species synthesizes an extracellular mannan-glucan complex (MGCx) which contributes to sequestration of antifungal drug, shielding the fungus from this external assault. Synthesis of a common polysaccharide backbone appears conserved. However, subtle structural differences in the branching side chains likely rely upon unique modification enzymes, which are species specific. Our findings identify MGCx backbone synthesis as a potential pan-
Candida
biofilm therapeutic target.
In Vivo
-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic
penA
Alleles That Confer Ceftriaxone Resistance in
Neisseria gonorrhoeae
Authors: Vincent Leah R. , Kerr Samuel R. , Tan Yang , Tomberg Joshua , Raterman Erica L. , Dunning Hotopp Julie C. , Unemo Magnus , Nicholas Robert A. , Jerse Ann E. 
Published: April 2018

ABSTRACT

Resistance to ceftriaxone in
Neisseria gonorrhoeae
is mainly conferred by mosaic
penA
alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic
penA
alleles on gonococcal fitness, we introduced the mosaic
penA
alleles from two ceftriaxone-resistant (Cro
r
) clinical isolates (H041 and F89) into a Cro
s
strain (FA19) by allelic exchange and showed that the resultant Cro
r
mutants were significantly outcompeted by the Cro
s
parent strain
in vitro
and in a murine infection model. Four Cro
r
compensatory mutants of FA19
penA41
were isolated independently from mice that outcompeted the parent strain both
in vitro
and
in vivo
. One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the
acnB
gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the
acnB

G348D

allele into FA19
penA41
conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19
penA41 acnB

G348D

revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cro
r
gonococcal strains that increase metabolism to ameliorate their fitness deficit.

IMPORTANCE
The emergence of ceftriaxone-resistant (Cro
r
)
Neisseria gonorrhoeae
has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of susceptible and resistant strains that differ only in the
penA
gene that confers Cro resistance. We showed that mosaic
penA
alleles found in Cro
r
clinical isolates are outcompeted by the Cro
s
parent strain
in vitro
and
in vivo
but that compensatory mutations that allow ceftriaxone resistance to be maintained by increasing bacterial fitness are selected during mouse infection. One compensatory mutant that was studied in more detail had a mutation in
acnB
, which encodes the aconitase that functions in the tricarboxylic acid (TCA) cycle. This study illustrates that compensatory mutations can be selected during infection, which we hypothesize may allow the spread of Cro resistance in nature. This study also provides novel insights into gonococcal metabolism and physiology.