bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examining the Role of Membrane Lipid Composition in Determining the Ethanol Tolerance of Saccharomyces cerevisiae
Authors: Henderson Clark M. , Block David E. 
Published: March 2014

ABSTRACTYeast (Saccharomyces cerevisiae) has an innate ability to withstand high levels of ethanol that would prove lethal to or severely impair the physiology of other organisms. Significant efforts have been undertaken to elucidate the biochemical and biophysical mechanisms of how ethanol interacts with lipid bilayers and cellular membranes. This research has implicated the yeast cellular membrane as the primary target of the toxic effects of ethanol. Analysis of model membrane systems exposed to ethanol has demonstrated ethanol's perturbing effect on lipid bilayers, and altering the lipid composition of these model bilayers can mitigate the effect of ethanol. In addition, cell membrane composition has been correlated with the ethanol tolerance of yeast cells. However, the physical phenomena behind this correlation are likely to be complex. Previous work based on often divergent experimental conditions and time-consuming low-resolution methodologies that limit large-scale analysis of yeast fermentations has fallen short of revealing shared mechanisms of alcohol tolerance inSaccharomyces cerevisiae. Lipidomics, a modern mass spectrometry-based approach to analyze the complex physiological regulation of lipid composition in yeast and other organisms, has helped to uncover potential mechanisms for alcohol tolerance in yeast. Recent experimental work utilizing lipidomics methodologies has provided a more detailed molecular picture of the relationship between lipid composition and ethanol tolerance. While it has become clear that the yeast cell membrane composition affects its ability to tolerate ethanol, the molecular mechanisms of yeast alcohol tolerance remain to be elucidated.
Carbon Flux Analysis by
13
C Nuclear Magnetic Resonance To Determine the Effect of CO
2
on Anaerobic Succinate Production by Corynebacterium glutamicum
Authors: Radoš Dušica , Turner David L. , Fonseca Luís L. , Carvalho Ana Lúcia , Blombach Bastian , Eikmanns Bernhard J. , Neves Ana Rute , Santos Helena 
Published: March 2014

ABSTRACT

Wild-type
Corynebacterium glutamicum
produces a mixture of lactic, succinic, and acetic acids from glucose under oxygen deprivation. We investigated the effect of CO
2
on the production of organic acids in a two-stage process: cells were grown aerobically in glucose, and subsequently, organic acid production by nongrowing cells was studied under anaerobic conditions. The presence of CO
2
caused up to a 3-fold increase in the succinate yield (1 mol per mol of glucose) and about 2-fold increase in acetate, both at the expense of
l
-lactate production; moreover, dihydroxyacetone formation was abolished. The redistribution of carbon fluxes in response to CO
2
was estimated by using
13
C-labeled glucose and
13
C nuclear magnetic resonance (NMR) analysis of the labeling patterns in end products. The flux analysis showed that 97% of succinate was produced via the reductive part of the tricarboxylic acid cycle, with the low activity of the oxidative branch being sufficient to provide the reducing equivalents needed for the redox balance. The flux via the pentose phosphate pathway was low (∼5%) regardless of the presence or absence of CO
2
. Moreover, there was significant channeling of carbon to storage compounds (glycogen and trehalose) and concomitant catabolism of these reserves. The intracellular and extracellular pools of lactate and succinate were measured by
in vivo
NMR, and the stoichiometry (H
+
:organic acid) of the respective exporters was calculated. This study shows that it is feasible to take advantage of natural cellular regulation mechanisms to obtain high yields of succinate with
C. glutamicum
without genetic manipulation.
Evaluation of a Disinfectant Wipe Intervention on Fomite-to-Finger Microbial Transfer
Authors: Lopez Gerardo U. , Kitajima Masaaki , Havas Aaron , Gerba Charles P. , Reynolds Kelly A. 
Published: March 2014

ABSTRACT

Inanimate surfaces, or fomites, can serve as routes of transmission of enteric and respiratory pathogens. No previous studies have evaluated the impact of surface disinfection on the level of pathogen transfer from fomites to fingers. Thus, the present study investigated the change in microbial transfer from contaminated fomites to fingers following disinfecting wipe use.
Escherichia coli
(10
8
to 10
9
CFU/ml),
Staphylococcus aureus
(10
9
CFU/ml),
Bacillus thuringiensis
spores (10
7
to 10
8
CFU/ml), and poliovirus 1 (10
8
PFU/ml) were seeded on ceramic tile, laminate, and granite in 10-μl drops and allowed to dry for 30 min at a relative humidity of 15 to 32%. The seeded fomites were treated with a disinfectant wipe and allowed to dry for an additional 10 min. Fomite-to-finger transfer trials were conducted to measure concentrations of transferred microorganisms on the fingers after the disinfectant wipe intervention. The mean log
10
reduction of the test microorganisms on fomites by the disinfectant wipe treatment varied from 1.9 to 5.0, depending on the microorganism and the fomite. Microbial transfer from disinfectant-wipe-treated fomites was lower (up to <0.1% on average) than from nontreated surfaces (up to 36.3% on average, reported in our previous study) for all types of microorganisms and fomites. This is the first study quantifying microbial transfer from contaminated fomites to fingers after the use of disinfectant wipe intervention. The data generated in the present study can be used in quantitative microbial risk assessment models to predict the effect of disinfectant wipes in reducing microbial exposure.
Sonorensin: an Antimicrobial Peptide, Belonging to the Heterocycloanthracin Subfamily of Bacteriocins, from a New Marine Isolate, Bacillus sonorensis MT93
Authors: Chopra Lipsy , Singh Gurdeep , Choudhary Vikas , Sahoo Debendra K. 
Published: March 2014

ABSTRACT

Marine environments are the greatest fronts of biodiversity, representing a resource of unexploited or unknown microorganisms and new substances having potential applications. Among microbial products, antimicrobial peptides (AMPs) have received great attention recently due to their applications as food preservatives and therapeutic agents. A new marine soil isolate producing an AMP was identified as
Bacillus sonorensis
based on 16S rRNA gene sequence analysis. It produced an AMP that showed a broad spectrum of activity against both Gram-positive and Gram-negative bacteria. The peptide, named sonorensin, was purified to homogeneity using a combination of chromatographic techniques. The intact molecular mass of the purified peptide, 6,274 Da, as revealed by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF), was in agreement with Tricine-SDS-PAGE analysis. A PCR array of primers was used to identify AMP structural genes, which allowed the successful amplification of the related genes from strain MT93. The putative open reading frame of sonorensin was amplified, cloned into the pET-32a(+) vector, expressed as a thioredoxin (Trx) fusion protein in
Escherichia coli
, and then purified. Sequence alignment analysis revealed that the bacteriocin being reported could belong to new subfamily of bacteriocins, heterocycloanthracin. The peptide indicated its potential as a biocontrol agent or food antimicrobial agent, due to its antimicrobial activity against bacteria such as
Listeria monocytogenes
and
Staphylococcus aureus
. This is the first report of the production, purification, and characterization of wild-type and recombinant bacteriocin by
B. sonorensis
and the first bacteriocin of the heterocycloanthracin subfamily to be characterized.
Genetic Validation of Trypanosoma brucei Glutathione Synthetase as an Essential Enzyme
Authors: Pratt Chelsea , Nguyen Suong , Phillips Margaret A. 
Published: March 2014

ABSTRACT

Human African trypanosomiasis (HAT) is a debilitating and fatal vector-borne disease. Polyamine biosynthesis is the target of one of the key drugs (eflornithine) used for the treatment of late-stage disease, suggesting that the pathway might be exploited for the identification of additional drug targets. The polyamine spermidine is required in trypanosomatid parasites for formation of a unique redox cofactor termed trypanothione, which is formed from the conjugation of glutathione to spermidine. Here we characterize recombinant
Trypanosoma brucei
glutathione synthetase (
Tb
GS) and show that depletion of
Tb
GS in blood-form parasites using a regulated knockout strategy leads to loss of trypanothione and to cell death as quantified by fluorescence-activated cell sorter (FACS) analysis. These data suggest that >97% depletion of
Tb
GS is required before trypanothione is depleted and cell growth arrest is observed. Exogenous glutathione was able to partially compensate for the loss of
Tb
GS, suggesting that parasites are able to transport intact glutathione. Finally, reduced expression of
Tb
GS leads to increased levels of upstream glutathione biosynthetic enzymes and decreased expression of polyamine biosynthetic enzymes, providing evidence that the cells cross regulate the two branches of the trypanothione biosynthetic pathway to maintain spermidine and trypanothione homeostasis.
A Role for the Rap GTPase YlRsr1 in Cellular Morphogenesis and the Involvement of YlRsr1 and the Ras GTPase YlRas2 in Bud Site Selection in the Dimorphic Yeast Yarrowia lipolytica
Authors: Li Yun-Qing , Li Min , Zhao Xiao-Feng , Gao Xiang-Dong 
Published: March 2014

ABSTRACT

Yarrowia lipolytica
is a dimorphic yeast species that can grow in the ovoid yeast form or in the elongated pseudohyphal or hyphal form depending on the growth conditions. Here, we show that the Rap GTPase Rsr1 of
Y. lipolytica
(YlRsr1) plays an important role in cellular morphogenesis in this microorganism. Cells deleted for Yl
RSR1
exhibited impaired polarized growth during yeast-form growth. Pseudohyphal and hyphal development were also abnormal. YlRsr1 is also important for cell growth, since the deletion of Yl
RSR1
in cells lacking the Ras GTPase YlRas2 caused lethality.
Y. lipolytica
cells bud in a bipolar pattern in which the cells produce the new buds at the two poles. YlRsr1 plays a prominent role in this bud site selection process. YlRsr1's function in bud site selection absolutely requires the cycling of YlRsr1 between the GTP- and GDP-bound states but its function in cellular morphogenesis does not, suggesting that the two processes are differentially regulated. Interestingly, the Ras GTPase YlRas2 is also involved in the control of bud site selection, as Yl
ras2
Δ cells were severely impaired in bipolar bud site selection. The GTP/GDP cycling and the plasma membrane localization of YlRas2 are important for YlRas2's function in bud site selection. However, they are not essential for this process, suggesting that the mechanism by which YlRas2 acts is different from that of YlRsr1. Our results suggest that YlRsr1 is regulated by the GTPase-activating protein (GAP) YlBud2 and partially by YlCdc25, the potential guanine nucleotide exchange factor (GEF) for YlRas2.
Amylocyclicin, a Novel Circular Bacteriocin Produced by Bacillus amyloliquefaciens FZB42
Authors: Scholz Romy , Vater Joachim , Budiharjo Anto , Wang Zhiyuan , He Yueqiu , Dietel Kristin , Schwecke Torsten , Herfort Stefanie , Lasch Peter , Borriss Rainer 
Published: March 2014

ABSTRACT

Bacillus amyloliquefaciens
FZB42 is a Gram-positive plant growth-promoting bacterium with an impressive capacity to synthesize nonribosomal secondary metabolites with antimicrobial activity. Here we report on a novel circular bacteriocin which is ribosomally synthesized by FZB42. The compound displayed high antibacterial activity against closely related Gram-positive bacteria. Transposon mutagenesis and subsequent site-specific mutagenesis combined with matrix-assisted laser desorption ionization–time of flight mass spectroscopy revealed that a cluster of six genes covering 4,490 bp was responsible for the production, modification, and export of and immunity to an antibacterial compound, here designated amylocyclicin, with a molecular mass of 6,381 Da. Peptide sequencing of the fragments obtained after tryptic digestion of the purified peptide revealed posttranslational cleavage of an N-terminal extension and head-to-tail circularization of the novel bacteriocin. Homology to other putative circular bacteriocins in related bacteria let us assume that this type of peptide is widespread among the
Bacillus/Paenibacillus
taxon.
Iron-Regulated Protein HupB of Mycobacterium tuberculosis Positively Regulates Siderophore Biosynthesis and Is Essential for Growth in Macrophages
Authors: Pandey Satya Deo , Choudhury Mitali , Yousuf Suhail , Wheeler Paul R. , Gordon Stephen V. , Ranjan Akash , Sritharan Manjula 
Published: March 2014

ABSTRACT

Mycobacterium tuberculosis
expresses the 28-kDa protein HupB (Rv2986c) and the Fe
3+
-specific high-affinity siderophores mycobactin and carboxymycobactin upon iron limitation. The objective of this study was to understand the functional role of HupB in iron acquisition. A
hupB
mutant strain of
M. tuberculosis
, subjected to growth in low-iron medium (0.02 μg Fe ml
−1
), showed a marked reduction of both siderophores with low transcript levels of the
mbt
genes encoding the MB biosynthetic machinery. Complementation of the mutant strain with
hupB
restored siderophore production to levels comparable to that of the wild type. We demonstrated the binding of HupB to the
mbtB
promoter by both electrophoretic mobility shift assays and DNA footprinting. The latter revealed the HupB binding site to be a 10-bp AT-rich region. While negative regulation of the
mbt
machinery by IdeR is known, this is the first report of positive regulation of the
mbt
operon by HupB. Interestingly, the mutant strain failed to survive inside macrophages, suggesting that HupB plays an important role
in vivo
.
Identification of a Novel Aminopropyltransferase Involved in the Synthesis of Branched-Chain Polyamines in Hyperthermophiles
Authors: Okada Kazuma , Hidese Ryota , Fukuda Wakao , Niitsu Masaru , Takao Koichi , Horai Yuhei , Umezawa Naoki , Higuchi Tsunehiko , Oshima Tairo , Yoshikawa Yuko , Imanaka Tadayuki , Fujiwara Shinsuke 
Published: March 2014

ABSTRACTLonger- and/or branched-chain polyamines are unique polycations found in thermophiles.N4-aminopropylspermine is considered a major polyamine inThermococcus kodakarensis. To determine whether a quaternary branched penta-amine,N4-bis(aminopropyl)spermidine, an isomer ofN4-aminopropylspermine, was also present, acid-extracted cytoplasmic polyamines were analyzed by high-pressure liquid chromatography, gas chromatography (HPLC), and gas chromatography-mass spectrometry.N4-bis(aminopropyl)spermidine was an abundant cytoplasmic polyamine in this species. To identify the enzyme that catalyzesN4-bis(aminopropyl)spermidine synthesis, the active fraction was concentrated from the cytoplasm and analyzed by linear ion trap–time of flight mass spectrometry with an electrospray ionization instrument after analysis by the MASCOT database. TK0545, TK0548, TK0967, and TK1691 were identified as candidate enzymes, and the corresponding genes were individually cloned and expressed inEscherichia coli. Recombinant forms were purified, and theirN4-bis(aminopropyl)spermidine synthesis activity was measured. Of the four candidates, TK1691 (BpsA) was found to synthesizeN4-bis(aminopropyl)spermidine from spermidine viaN4-aminopropylspermidine. Compared to the wild type, thebpsA-disrupted strain DBP1 grew at 85°C with a slightly longer lag phase but was unable to grow at 93°C. HPLC analysis showed that bothN4-aminopropylspermidine andN4-bis(aminopropyl)spermidine were absent from the DBP1 strain grown at 85°C, demonstrating that the branched-chain polyamine synthesized by BpsA is important for cell growth at 93°C. Sequence comparison to orthologs from various microorganisms indicated that BpsA differed from other known aminopropyltransferases that produce spermidine and spermine. BpsA orthologs were found only in thermophiles, both in archaea and bacteria, but were absent from mesophiles. These findings indicate that BpsA is a novel aminopropyltransferase essential for the synthesis of branched-chain polyamines, enabling thermophiles to grow in high-temperature environments.
Acupuncture and Standard Emergency Department Care for Pain And/Or Nausea and Its Impact on Emergency Care Delivery: A Feasibility Study
Authors: Zhang Anthony L , Parker Shefton J , Smit De Villiers , Taylor David McD , Xue Charlie C L 
Published: March 2014

Objective To evaluate the feasibility of delivering acupuncture in an emergency department (ED) to patients presenting with pain and/or nausea. Methods A feasibility study (with historical controls) undertaken at the Northern Hospital ED in Melbourne, Australia, involving people presenting to ED triage with pain (VAS 0–10) and/or nausea (Morrow Index 1–6) between January and August 2010 (n=400). The acupuncture group comprised 200 patients who received usual medical care and acupuncture; the usual care group comprised 200 patients with retrospective data closely matched from ED electronic health records. Results Refusal rate was 31%, with ‘symptoms under control owing to medical treatment before acupuncture’ the most prevalent reason for refusal (n=36); 52.5% of participants responded ‘definitely yes’ for their willingness to repeat acupuncture, and a further 31.8% responded ‘probably yes’. Over half (57%) reported a satisfaction score of 10 for acupuncture treatment. Musculoskeletal conditions were the most common conditions treated n=117 (58.5%), followed by abdominal or flank pain n=49 (24.5%). Adverse events were rare (2%) and mild. Pain and nausea scores reduced from a mean±SD of 7.01±2.02 before acupuncture to 4.72±2.62 after acupuncture and from 2.6±2.19 to 1.42±1.86, respectively. Conclusions Acupuncture in the ED appears safe and acceptable for patients with pain and/or nausea. Results suggest combined care may provide effective pain and nausea relief in ED patients. Further high-quality, sufficiently powered randomised studies evaluating the cost-effectiveness and efficacy of the add-on effect of acupuncture are recommended.
Integration of HIV and maternal healthcare in a high HIV-prevalence setting: analysis of client flow data over time in Swaziland
Authors: Birdthistle Isolde J , Mayhew Susannah H , Kikuvi Joshua , Zhou Weiwei , Church Kathryn , Warren Charlotte E , Nkambule Rejoice , Fenty Justin ,   on behalf of the Integra Initiative
Published: March 2014

ObjectiveMaternal and child health (MCH) care may provide an entry point for HIV services in high HIV-prevalence settings. Our objective was to assess integration of HIV with MCH services in public sector facilities in Swaziland.DesignIn 2009, 2010 and 2012, client flow assessments (CFAs) were conducted over 5 days in the MCH units of eight government facilities, purposively selected as intervention or comparison sites.Participants8263 MCH visits with female clients were tracked: 3261 in 2009, 2086 in 2010 and 2916 in 2012.InterventionActivities and resources to strengthen integration of HIV services into postnatal care (PNC), 2009–2010.Main outcome measuresThe proportion of all visits in which an HIV/sexually transmitted infection (STI) testing, counselling or treatment was received together with an MCH service; the proportion of all visits in which a client receives HIV counselling.ResultsAcross facilities, the proportion of visits in which HIV/STI and MCH services were received varied considerably, for example, from 9% to 49% in 2009. HIV/STI services were integrated most frequently with child health (CH), antenatal care (ANC) and family planning (FP)—the most common reasons for women's attendance—and least often with PNC and cervical screening (CS). There was no meaningful difference in integration over time by design group and considerable heterogeneity across facilities. Receipt of integrated services increased in one intervention and two comparison facilities, where HIV counselling also rose, and fell in one intervention and two comparison facilities.ConclusionsProvision of HIV/STI services with MCH care occurred at all facilities, yet relatively few women receive integrated services. Increases in integration were driven by increases in HIV counselling, while sharp declines in some facilities indicate that integration is difficult to sustain. Opportunities for intensifying HIV integration lie with ANC, CH and FP, while HIV-PNC integration will remain limited until more women attend PNC.Trial registration numberCurrent Controlled TrialsNCT01694862.
Systematic review of percutaneous closure versus medical therapy in patients with cryptogenic stroke and patent foramen ovale
Authors: Spencer Frederick A , Lopes Luciane C , Kennedy Sean A , Guyatt Gordon 
Published: March 2014

ObjectivesTo provide a comprehensive comparison of patent foramen ovale (PFO) closure versus medical therapy in patients with cryptogenic stroke or transient ischaemic attack (TIA) and demonstrated PFO.DesignSystematic review with complete case meta-analysis and sensitivity analyses. Data sources included MEDLINE and EMBASE from 1980 up to May 2013. All randomised controlled trials (RCTs) comparing treatment with percutaneous catheter-based closure of PFO to anticoagulant or antiplatelet therapy in patients with cryptogenic stroke or TIA and echocardiographically confirmed PFO or atrial septal defect (ASD) were eligible.Participants1967 participants with prior stroke or TIA and echocardiographically confirmed PFO or ASD.Primary outcome measuresThe primary outcome of interest was recurrence of ischaemic stroke. We utilised data from complete cases only for the primary endpoint and combined data from trials to estimate the pooled risk ratio (RR) and associated 95% CIs calculated using random effects models.ResultsWe identified 284 potentially eligible articles of which three RCTs including 2303 patients proved eligible and 1967 patients had complete data. Of the 1026 patients randomised to PFO closure and followed to study conclusion 22 experienced non-fatal ischaemic strokes, as did 34 of 941 patients randomised to medical therapy (risk ratio (RR) 0.61, 95% CI 0.34 to 1.07; heterogeneity: p=0.34, I2=8%, confidence in estimates low due to risk of bias and imprecision). Analyses for ischaemic stroke restricted to ‘per-protocol’ patients or patients with concomitant atrial septal aneurysm did not substantially change the observed RRs. Complication rates associated with either PFO closure or medical therapy were low.ConclusionsPooled data from three RCTs provides insufficient support that PFO closure is preferable to medical therapy for secondary prevention of cryptogenic stroke in patients with PFO.