bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extracellular Polymeric Substance Architecture Influences Natural Genetic Transformation of Acinetobacter baylyi in Biofilms
Authors: Merod Robin T. , Wuertz Stefan 
Published: October 2014

ABSTRACT

Genetic exchange by natural transformation is an important mechanism of horizontal gene transfer in biofilms. Thirty-two biofilm metrics were quantified in a heavily encapsulated
Acinetobacter baylyi
strain and a miniencapsulated mutant strain, accounting for cellular architecture, extracellular polymeric substances (EPS) architecture, and their combined biofilm architecture. In general, transformation location, abundance, and frequency were more closely correlated to EPS architecture than to cellular or combined architecture. Transformation frequency and transformant location had the greatest correlation with the EPS metric surface area-to-biovolume ratio. Transformation frequency peaked when EPS surface area-to-biovolume ratio was greater than 3 μm
2
/μm
3
and less than 5 μm
2
/μm
3
. Transformant location shifted toward the biofilm-bulk fluid interface as the EPS surface area-to-biovolume ratio increased. Transformant biovolume was most closely correlated with EPS biovolume and peaked when transformation occurred in close proximity to the substratum. This study demonstrates that biofilm architecture influences
A. baylyi
transformation frequency and transformant location and abundance. The major role of EPS may be to facilitate the binding and stabilization of plasmid DNA for cellular uptake.
The Antimicrobial Mechanism of Action of Epsilon-Poly-
l
-Lysine
Authors: Hyldgaard Morten , Mygind Tina , Vad Brian S. , Stenvang Marcel , Otzen Daniel E. , Meyer Rikke L. 
Published: October 2014

ABSTRACT

Epsilon-poly-
l
-lysine (ε-PL) is a natural antimicrobial cationic peptide which is generally regarded as safe (GRAS) as a food preservative. Although its antimicrobial activity is well documented, its mechanism of action is only vaguely described. The aim of this study was to clarify ε-PL's mechanism of action using
Escherichia coli
and
Listeria innocua
as model organisms. We examined ε-PL's effect on cell morphology and membrane integrity and used an array of
E. coli
deletion mutants to study how specific outer membrane components affected the action of ε-PL. We furthermore studied its interaction with lipid bilayers using membrane models.
In vitro
cell studies indicated that divalent cations and the heptose I and II phosphate groups in the lipopolysaccharide layer of
E. coli
are critical for ε-PL's binding efficiency. ε-PL removed the lipopolysaccharide layer and affected cell morphology of
E. coli
, while
L. innocua
underwent minor morphological changes. Propidium iodide staining showed that ε-PL permeabilized the cytoplasmic membrane in both species, indicating the membrane as the site of attack. We compared the interaction with neutral or negatively charged membrane systems and showed that the interaction with ε-PL relied on negative charges on the membrane. Suspended membrane vesicles were disrupted by ε-PL, and a detergent-like disruption of
E. coli
membrane was confirmed by atomic force microscopy imaging of supported lipid bilayers. We hypothesize that ε-PL destabilizes membranes in a carpet-like mechanism by interacting with negatively charged phospholipid head groups, which displace divalent cations and enforce a negative curvature folding on membranes that leads to formation of vesicles/micelles.
Investigating the Function of an Arabinan Utilization Locus Isolated from a Termite Gut Community
Authors: Arnal Grégory , Bastien Géraldine , Monties Nelly , Abot Anne , Anton Leberre Véronique , Bozonnet Sophie , O'Donohue Michael , Dumon Claire 
Published: October 2014

ABSTRACT

Biocatalysts are essential for the development of bioprocesses efficient for plant biomass degradation. Previously, a metagenomic clone containing DNA from termite gut microbiota was pinpointed in a functional screening that revealed the presence of arabinofuranosidase activity. Subsequent genetic and bioinformatic analysis revealed that the DNA fragment belonged to a member of the genus
Bacteroides
and encoded 19 open reading frames (ORFs), and annotation suggested the presence of hypothetical transporter and regulator proteins and others involved in the catabolism of pentose sugar. In this respect and considering the phenotype of the metagenomic clone, it was noted that among the ORFs, there are four putative arabinose-specific glycoside hydrolases, two from family GH43 and two from GH51. In this study, a thorough bioinformatics analysis of the metagenomic clone gene cluster has been performed and the four aforementioned glycoside hydrolases have been characterized. Together, the results provide evidence that the gene cluster is a polysaccharide utilization locus dedicated to the breakdown of the arabinan component in pectin and related substrates. Characterization of the two GH43 and the two GH51 glycoside hydrolases has revealed that each of these enzymes displays specific catalytic capabilities and that when these are combined the enzymes act synergistically, increasing the efficiency of arabinan degradation.
The Western Progression of Lyme Disease: Infectious and Nonclonal
Borrelia burgdorferi Sensu Lato
Populations in Grand Forks County, North Dakota
Authors: Stone Brandee L. , Russart Nathan M. , Gaultney Robert A. , Floden Angela M. , Vaughan Jefferson A. , Brissette Catherine A. 
Published: October 2014

ABSTRACT

Scant attention has been paid to Lyme disease,
Borrelia burgdorferi
,
Ixodes scapularis
, or reservoirs in eastern North Dakota despite the fact that it borders high-risk counties in Minnesota. Recent reports of
B. burgdorferi
and
I. scapularis
in North Dakota, however, prompted a more detailed examination. Spirochetes cultured from the hearts of five rodents trapped in Grand Forks County, ND, were identified as
B. burgdorferi sensu lato
through sequence analyses of the 16S rRNA gene, the 16S rRNA gene-
ileT
intergenic spacer region,
flaB
,
ospA
,
ospC
, and
p66
. OspC typing revealed the presence of groups A, B, E, F, L, and I. Two rodents were concurrently carrying multiple OspC types. Multilocus sequence typing suggested the eastern North Dakota strains are most closely related to those found in neighboring regions of the upper Midwest and Canada. BALB/c mice were infected with
B. burgdorferi
isolate M3 (OspC group B) by needle inoculation or tick bite. Tibiotarsal joints and ear pinnae were culture positive, and
B. burgdorferi
M3 was detected by quantitative PCR (qPCR) in the tibiotarsal joints, hearts, and ear pinnae of infected mice. Uninfected larval
I. scapularis
ticks were able to acquire
B. burgdorferi
M3 from infected mice; M3 was maintained in
I. scapularis
during the molt from larva to nymph; and further, M3 was transmitted from infected
I. scapularis
nymphs to naive mice, as evidenced by cultures and qPCR analyses. These results demonstrate that isolate M3 is capable of disseminated infection by both artificial and natural routes of infection. This study confirms the presence of unique (nonclonal) and infectious
B. burgdorferi
populations in eastern North Dakota.
Isolation of Acetogenic Bacteria That Induce Biocorrosion by Utilizing Metallic Iron as the Sole Electron Donor
Authors: Kato Souichiro , Yumoto Isao , Kamagata Yoichi 
Published: October 2014

ABSTRACT

Corrosion of iron occurring under anoxic conditions, which is termed microbiologically influenced corrosion (MIC) or biocorrosion, is mostly caused by microbial activities. Microbial activity that enhances corrosion via uptake of electrons from metallic iron [Fe(0)] has been regarded as one of the major causative factors. In addition to sulfate-reducing bacteria and methanogenic archaea in marine environments, acetogenic bacteria in freshwater environments have recently been suggested to cause MIC under anoxic conditions. However, no microorganisms that perform acetogenesis-dependent MIC have been isolated or had their MIC-inducing mechanisms characterized. Here, we enriched and isolated acetogenic bacteria that induce iron corrosion by utilizing Fe(0) as the sole electron donor under freshwater, sulfate-free, and anoxic conditions. The enriched communities produced significantly larger amounts of Fe(II) than the abiotic controls and produced acetate coupled with Fe(0) oxidation prior to CH
4
production. Microbial community analysis revealed that
Sporomusa
sp. and
Desulfovibrio
sp. dominated in the enrichments. Strain GT1, which is closely related to the acetogen
Sporomusa sphaeroides
, was eventually isolated from the enrichment. Strain GT1 grew acetogenetically with Fe(0) as the sole electron donor and enhanced iron corrosion, which is the first demonstration of MIC mediated by a pure culture of an acetogen. Other well-known acetogenic bacteria, including
Sporomusa ovata
and
Acetobacterium
spp., did not grow well on Fe(0). These results indicate that very few species of acetogens have specific mechanisms to efficiently utilize cathodic electrons derived from Fe(0) oxidation and induce iron corrosion.
Proximity Effect among Cellulose-Degrading Enzymes Displayed on the Saccharomyces cerevisiae Cell Surface
Authors: Bae Jungu , Kuroda Kouichi , Ueda Mitsuyoshi 
Published: October 2014

ABSTRACT

Proximity effect is a form of synergistic effect exhibited when cellulases work within a short distance from each other, and this effect can be a key factor in enhancing saccharification efficiency. In this study, we evaluated the proximity effect between 3 cellulose-degrading enzymes displayed on the
Saccharomyces cerevisiae
cell surface, that is, endoglucanase, cellobiohydrolase, and β-glucosidase. We constructed 2 kinds of arming yeasts through genome integration: ALL-yeast, which simultaneously displayed the 3 cellulases (thus, the different cellulases were near each other), and MIX-yeast, a mixture of 3 kinds of single-cellulase-displaying yeasts (the cellulases were far apart). The cellulases were tagged with a fluorescence protein or polypeptide to visualize and quantify their display. To evaluate the proximity effect, we compared the activities of ALL-yeast and MIX-yeast with respect to degrading phosphoric acid-swollen cellulose after adjusting for the cellulase amounts. ALL-yeast exhibited 1.25-fold or 2.22-fold higher activity than MIX-yeast did at a yeast concentration equal to the yeast cell number in 1 ml of yeast suspension with an optical density (OD) at 600 nm of 10 (OD10) or OD0.1. At OD0.1, the distance between the 3 cellulases was greater than that at OD10 in MIX-yeast, but the distance remained the same in ALL-yeast; thus, the difference between the cellulose-degrading activities of ALL-yeast and MIX-yeast increased (to 2.22-fold) at OD0.1, which strongly supports the proximity effect between the displayed cellulases. A proximity effect was also observed for crystalline cellulose (Avicel). We expect the proximity effect to further increase when enzyme display efficiency is enhanced, which would further increase cellulose-degrading activity. This arming yeast technology can also be applied to examine proximity effects in other diverse fields.
Acquisition of the Ability To Assimilate Mannitol by Saccharomyces cerevisiae through Dysfunction of the General Corepressor Tup1-Cyc8
Authors: Chujo Moeko , Yoshida Shiori , Ota Anri , Murata Kousaku , Kawai Shigeyuki 
Published: October 2014

ABSTRACT

Saccharomyces cerevisiae
normally cannot assimilate mannitol, a promising brown macroalgal carbon source for bioethanol production. The molecular basis of this inability remains unknown. We found that cells capable of assimilating mannitol arose spontaneously from wild-type
S. cerevisiae
during prolonged culture in mannitol-containing medium. Based on microarray data, complementation analysis, and cell growth data, we demonstrated that acquisition of mannitol-assimilating ability was due to spontaneous mutations in the genes encoding Tup1 or Cyc8, which constitute a general corepressor complex that regulates many kinds of genes. We also showed that an
S. cerevisiae
strain carrying a mutant allele of
CYC8
exhibited superior salt tolerance relative to other ethanologenic microorganisms; this characteristic would be highly beneficial for the production of bioethanol from marine biomass. Thus, we succeeded in conferring the ability to assimilate mannitol on
S. cerevisiae
through dysfunction of Tup1-Cyc8, facilitating production of ethanol from mannitol.
Effect of Transcutaneous Electrical Acupuncture Point Stimulation on Endometrial Receptivity in Women Undergoing Frozen-Thawed Embryo Transfer: A Single-Blind Prospective Randomised Controlled Trial
Authors: Shuai Zhenhong , Lian Fang , Li Pengfei , Yang Wenxiu 
Published: October 2014

Objective To evaluate the effect of transcutaneous electrical acupuncture point stimulation (TEAS) on endometrial HOXA10 protein expression and three-dimensional (3D) power Doppler ultrasound parameters as markers of endometrial receptivity in women undergoing frozen-thawed embryo transfer (FET). Methods A total of 68 women undergoing FET were randomised to receive TEAS or mock TEAS at acupuncture points CV3, CV4 and SP6 and Zigong bilaterally. Both groups had six sessions per cycle for three menstrual cycles prior to the scheduled FET. Each session lasted 30 min and was repeated every other day. 3D power Doppler ultrasound parameters, HOXA10 protein expression and rates of embryo implantation, clinical pregnancy and live birth were compared. Results There were no significant differences between the two groups in endometrial thickness or endometrial volume. The ultrasonographic endometrial triple-line pattern was present more often in the TEAS group (p=0.002). The TEAS group had a greater endometrial and subendometrial vascularisation index (VI) than the mock TEAS group (p=0.001 and p<0.001, respectively) on 3D ultrasound and increased endometrial HOXA10 expression (p=0.001) immediately prior to FET. Subsequently, the rates of embryo implantation, clinical pregnancy and live birth rates were all higher in the TEAS group than in the mock TEAS group (p=0.024, p=0.038 and p=0.033, respectively). Conclusions In patients undergoing FET, TEAS may have beneficial effects on endometrial HOXA10 expression and ultrasound markers of endometrial receptivity. These findings may explain the improvement in clinical outcome of FET associated with the use of TEAS. Trial Registration Number ChiCTR-TRC-14004448.
Antipsychotic treatment for children and adolescents with schizophrenia spectrum disorders: protocol for a network meta-analysis of randomised trials
Authors: Pagsberg A K , Tarp S , Glintborg D , Stenstrøm A D , Fink-Jensen A , Correll C U , Christensen R 
Published: October 2014

IntroductionAntipsychotic treatment in early-onset schizophrenia (EOS) lacks a rich evidence base, and efforts to rank different drugs concerning their efficacy have not proven any particular drug superior. In contrast to the literature regarding adult-onset schizophrenia (AOS), comparative effectiveness studies in children and adolescents are limited in number and size, and only a few meta-analyses based on conventional methodologies have been conducted.Methods and analysesWe will conduct a network meta-analysis of all randomised controlled trials (RCTs) that evaluate antipsychotic therapies for EOS to determine which compounds are efficacious, and to determine the relative efficacy and safety of these treatments when compared in a network meta-analysis.Unlike a contrast-based (standard) meta-analysis approach, an arm-based network meta-analysis enables statistical inference from combining both direct and indirect comparisons within anempirical Bayesframework. We will acquire eligible studies through a systematic search of MEDLINE, the Cochrane Central Registry of Controlled Trials, Clinicaltrials.gov and Centre for Reviews and Dissemination databases. Eligible studies should randomly allocate children and adolescents presenting with schizophrenia or a related non-affective psychotic condition to an intervention group or to a control group. Two reviewers will—independently and in duplicate—screen titles and abstracts, complete full text reviews to determine eligibility, and subsequently perform data abstraction and assess risk of bias of eligible trials. We will conduct meta-analyses to establish the effect of all reported therapies on patient-relevant efficacy and safety outcomes when possible.Ethics and disseminationNo formal ethical procedures regarding informed consent are required as no primary data collection is undertaken. The review will help facilitate evidence-based management, identify key areas for future research, and provide a framework for conducting large systematic reviews combining direct and indirect comparisons. The study will be disseminated by peer-reviewed publication and conference presentation.Trial registration numberPROSPERO CRD42013006676.
Validity and accuracy of maternal tactile assessment for fever in under-five children in North Central Nigeria: a cross-sectional study
Authors: Abdulkadir Mohammed Baba , Johnson Wahab Babatunde Rotimi , Ibraheem Rasheedah Mobolaji 
Published: October 2014

ObjectivesThis study seeks to determine not only the reliability of parental touch in detecting fever as compared to rectal thermometry in under-five children, but also the sociodemographic factors that may predict its reliability.SettingThe study was carried out in the Emergency Paediatric Unit of a tertiary hospital in North Central Nigeria.Participants409 children aged less than 5 years with a history of fever in the 48 h prior to presentation and their mothers were recruited consecutively. All the children recruited completed the study. Children with clinical parameters suggestive of shock, and those who were too ill, were excluded from the study.Primary and secondary outcome measuresThe primary outcome was the proportion of mothers who could accurately predict if their child was febrile or not (defined by rectal temperature) using tactile assessment only. Secondary outcomes were the validity and accuracy of touch in detecting fever and factors related to its accuracy.ResultsAbout 85% of the children were febrile using rectal thermometry. The sensitivity, specificity, positive predictive and negative predictive values for touch as a screening tool were 63%, 54%, 88.3% and 21%, respectively. High maternal socioeconomic status and low maternal age influenced positively the accuracy of touch in correctly determining the presence or absence of fever.ConclusionsThis study has shown that tactile assessment of temperature is not reliable and that absence of fever in a previously febrile child should be confirmed by objective methods of temperature measurement.
Patient-Derived Ovarian Tumor Xenografts Recapitulate Human Clinicopathology and Genetic Alterations
Authors: Ricci Francesca , Bizzaro Francesca , Cesca Marta , Guffanti Federica , Ganzinelli Monica , Decio Alessandra , Ghilardi Carmen , Perego Patrizia , Fruscio Robert , Buda Alessandro , Milani Rodolfo , Ostano Paola , Chiorino Giovanna , Bani Maria Rosa , Damia Giovanna , Giavazzi Raffaella 
Published: October 2014

Abstract
Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. On the basis of its histopathology and molecular-genomic changes, ovarian cancer has been divided into subtypes, each with distinct biology and outcome. The aim of this study was to develop a panel of patient-derived EOC xenografts that recapitulate the molecular and biologic heterogeneity of human ovarian cancer. Thirty-four EOC xenografts were successfully established, either subcutaneously or intraperitoneally, in nude mice. The xenografts were histologically similar to the corresponding patient tumor and comprised all the major ovarian cancer subtypes. After orthotopic transplantation in the bursa of the mouse ovary, they disseminate into the organs of the peritoneal cavity and produce ascites, typical of ovarian cancer. Gene expression analysis and mutation status indicated a high degree of similarity with the original patient and discriminate different subsets of xenografts. They were very responsive, responsive, and resistant to cisplatin, resembling the clinical situation in ovarian cancer. This panel of patient-derived EOC xenografts that recapitulate the recently type I and type II classification serves to study the biology of ovarian cancer, identify tumor-specific molecular markers, and develop novel treatment modalities. Cancer Res; 74(23); 6980–90. ©2014 AACR.
Molecular Modulation of Estrogen-Induced Apoptosis by Synthetic Progestins in Hormone Replacement Therapy: An Insight into the Women's Health Initiative Study
Authors: Sweeney Elizabeth E. , Fan Ping , Jordan V. Craig 
Published: October 2014

Abstract
Hormone replacement therapy (HRT) is widely used to manage menopausal symptoms in women and can be comprised of an estrogen alone or an estrogen combined with a progestin. The Women's Health Initiative demonstrated in their randomized trials that estrogen alone HRT decreases the risk of breast cancer in postmenopausal women, whereas combined estrogen plus a progestin (medroxyprogesterone acetate, MPA) HRT increases this risk. Long-term estrogen-deprived MCF-7:5C cells were used to model the postmenopausal breast cancer cell environment. MPA is able to modify E2-induced apoptosis in MCF-7:5C cells. MPA, similar to dexamethasone, increases glucocorticoid receptor (GR) transcriptional activity, increases SGK1, a GR target gene, and can be blocked by RU486 (an antiglucocorticoid), suggesting that it functions through the GR. Norethindrone acetate (NETA), another progestin used in HRT, acts like an estrogen at high doses, upregulating estrogen receptor target genes and generating apoptosis in MCF-7:5C cells. The data suggest that women taking HRT comprising an estrogen plus MPA may have an increased risk of breast cancer due to MPA acting as a glucocorticoid and blunting E2-induced apoptosis in this environment. Therefore, perhaps other approved progestins (e.g., NETA) should be considered as alternatives to MPA. Cancer Res; 74(23); 7060–8. ©2014 AACR.
Chemotherapeutic Agents Subvert Tumor Immunity by Generating Agonists of Platelet-Activating Factor
Authors: Sahu Ravi P. , Ocana Jesus A. , Harrison Kathleen A. , Ferracini Matheus , Touloukian Christopher E. , Al-Hassani Mohammed , Sun Louis , Loesch Mathew , Murphy Robert C. , Althouse Sandra K. , Perkins Susan M. , Speicher Paul J. , Tyler Douglas S. , Konger Raymond L. , Travers Jeffrey B. 
Published: October 2014

AbstractOxidative stress suppresses host immunity by generating oxidized lipid agonists of the platelet-activating factor receptor (PAF-R). Because many classical chemotherapeutic drugs induce reactive oxygen species (ROS), we investigated whether these drugs might subvert host immunity by activating PAF-R. Here, we show that PAF-R agonists are produced in melanoma cells by chemotherapy that is administered in vitro, in vivo, or in human subjects. Structural characterization of the PAF-R agonists induced revealed multiple oxidized glycerophosphocholines that are generated nonenzymatically. In a murine model of melanoma, chemotherapeutic administration could augment tumor growth by a PAF-R–dependent process that could be blocked by treatment with antioxidants or COX-2 inhibitors or by depletion of regulatory T cells. Our findings reveal how PAF-R agonists induced by chemotherapy treatment can promote treatment failure. Furthermore, they offer new insights into how to improve the efficacy of chemotherapy by blocking its heretofore unknown impact on PAF-R activation. Cancer Res; 74(23); 7069–78. ©2014 AACR.