bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane Lipid Peroxidation in Copper Alloy-Mediated Contact Killing of Escherichia coli
Authors: Hong Robert , Kang Tae Y. , Michels Corinne A. , Gadura Nidhi 
Published: January 2012

ABSTRACT

Copper alloy surfaces are passive antimicrobial sanitizing agents that kill bacteria, fungi, and some viruses. Studies of the mechanism of contact killing in
Escherichia coli
implicate the membrane as the target, yet the specific component and underlying biochemistry remain unknown. This study explores the hypothesis that nonenzymatic peroxidation of membrane phospholipids is responsible for copper alloy-mediated surface killing. Lipid peroxidation was monitored with the thiobarbituric acid-reactive substances (TBARS) assay. Survival, TBARS levels, and DNA degradation were followed in cells exposed to copper alloy surfaces containing 60 to 99.90% copper or in medium containing CuSO
4
. In all cases, TBARS levels increased with copper exposure levels. Cells exposed to the highest copper content alloys, C11000 and C24000, exhibited novel characteristics. TBARS increased immediately at a very rapid rate but peaked at about 30 min. This peak was associated with the period of most rapid killing, loss in membrane integrity, and DNA degradation. DNA degradation is not the primary cause of copper-mediated surface killing. Cells exposed to the 60% copper alloy for 60 min had fully intact genomic DNA but no viable cells. In a
fabR
mutant strain with increased levels of unsaturated fatty acids, sensitivity to copper alloy surface-mediated killing increased, TBARS levels peaked earlier, and genomic DNA degradation occurred sooner than in the isogenic parental strain. Taken together, these results suggest that copper alloy surface-mediated killing of
E. coli
is triggered by nonenzymatic oxidative damage of membrane phospholipids that ultimately results in the loss of membrane integrity and cell death.
Identification of the Haloarchaeal Phasin (PhaP) That Functions in Polyhydroxyalkanoate Accumulation and Granule Formation in Haloferax mediterranei
Authors: Cai Shuangfeng , Cai Lei , Liu Hailong , Liu Xiaoqing , Han Jing , Zhou Jian , Xiang Hua 
Published: January 2012

ABSTRACT

The polyhydroxyalkanoate (PHA) granule-associated proteins (PGAPs) are important for PHA synthesis and granule formation, but currently little is known about the haloarchaeal PGAPs. This study focused on the identification and functional analysis of the PGAPs in the haloarchaeon
Haloferax mediterranei
. These PGAPs were visualized with two-dimensional gel electrophoresis (2-DE) and identified by matrix-assisted laser desorption ionization–tandem time of flight mass spectrometry (MALDI-TOF/TOF MS). The most abundant protein on the granules was identified as a hypothetical protein, designated PhaP. A genome-wide analysis revealed that the
phaP
gene is located upstream of the previously identified
phaEC
genes. Through an integrative approach of gene knockout/complementation and fermentation analyses, we demonstrated that this PhaP is involved in PHA accumulation. The Δ
phaP
mutant was defective in both PHA biosynthesis and cell growth compared to the wild-type strain. Additionally, transmission electron microscopy results indicated that the number of PHA granules in the Δ
phaP
mutant cells was significantly lower, and in most of the Δ
phaP
cells only a single large granule was observed. These results demonstrated that the
H. mediterranei
PhaP was the predominant structure protein (phasin) on the PHA granules involved in PHA accumulation and granule formation. In addition, BLASTp and phylogenetic results indicate that this type of PhaP is exclusively conserved in haloarchaea, implying that it is a representative of the haloarchaeal type PHA phasin.
Prevalence, Characterization, and Antimicrobial Resistance of Listeria monocytogenes Isolates from Bovine Hides and Carcasses
Authors: Wieczorek Kinga , Dmowska Katarzyna , Osek Jacek 
Published: January 2012

ABSTRACT

Listeria monocytogenes
isolates from bovine hides and carcasses (
n
= 812) were mainly of serogroup 1/2a. All strains were positive for internalin genes. Several isolates were resistant to oxacillin (72.2%) or clindamycin (37.0%). These findings indicate that
L. monocytogenes
of beef origin can be considered a public health concern.
Culture-Independent Approaches for Studying Viruses from Hypersaline Environments
Authors: Santos Fernando , Yarza Pablo , Parro Víctor , Meseguer Inmaculada , Rosselló-Móra Ramon , Antón Josefa 
Published: January 2012

ABSTRACT
Hypersaline close-to-saturation environments harbor an extremely high concentration of virus-like particles, but the number of haloviruses isolated so far is still very low. Haloviruses can be directly studied from natural samples by using different culture-independent techniques that include transmission electron microscopy, pulsed-field gel electrophoresis, and different metagenomic approaches. Here, we review the findings of these studies, with a main focus on the metagenomic approaches. The analysis of bulk viral nucleic acids directly retrieved from the environment allows estimations of viral diversity, activity, and dynamics and tentative host assignment. Results point to a diverse and active viral community in constant interplay with its hosts and to a “hypersalineness” quality common to viral assemblages present in hypersaline environments that are thousands of kilometers away from each other.
Characterization of Airborne Bacteria at an Underground Subway Station
Authors: Dybwad Marius , Granum Per Einar , Bruheim Per , Blatny Janet Martha 
Published: January 2012

ABSTRACT

The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera
Bacillus
,
Micrococcus
, and
Staphylococcus
, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.
Design of Chimeric Levansucrases with Improved Transglycosylation Activity
Authors: Olvera Clarita , Centeno-Leija Sara , Ruiz-Leyva Paulina , López-Munguía Agustín 
Published: January 2012

ABSTRACT

Fructansucrases (FSs), including levansucrases and inulosucrases, are enzymes that synthesize fructose polymers from sucrose by the direct transfer of the fructosyl moiety to a growing polymer chain. These enzymes, particularly the single domain fructansucrases, also possess an important hydrolytic activity, which may account for as much as 70 to 80% of substrate conversion, depending on reaction conditions. Here, we report the construction of four chimeric levansucrases from SacB, a single domain levansucrase produced by
Bacillus subtilis
. Based on observations derived from the effect of domain deletion in both multidomain fructansucrases and glucansucrases, we attached different extensions to SacB. These extensions included the transitional domain and complete C-terminal domain of
Leuconostoc citreum
inulosucrase (IslA),
Leuconostoc mesenteroides
levansucrase (LevC), and a
L. mesenteroides
glucansucrase (DsrP). It was found that in some cases the hydrolytic activity was reduced to less than 10% of substrate conversion; however, all of the constructs were as stable as SacB. This shift in enzyme specificity was observed even when the SacB catalytic domain was extended only with the transitional region found in multidomain FSs. Specific kinetic analysis revealed that this change in specificity of the SacB chimeric constructs was derived from a 5-fold increase in the transfructosylation
k
cat
and not from a reduction of the hydrolytic
k
cat
, which remained constant.
Human-Associated Extended-Spectrum β-Lactamase in the Antarctic
Authors: Hernández Jorge , Stedt Johan , Bonnedahl Jonas , Molin Ylva , Drobni Mirva , Calisto-Ulloa Nancy , Gomez-Fuentes Claudio , Astorga-España M. Soledad , González-Acuña Daniel , Waldenström Jonas , Blomqvist Maria , Olsen Björn 
Published: January 2012

ABSTRACT

Escherichia coli
bacteria with extended-spectrum β-lactamase (ESBL) type CTX-M resistance were isolated from water samples collected close to research stations in Antarctica. The isolates had
bla
CTX-M-1
and
bla
CTX-M-15
genotypes and sequence types (ST) indicative of a human-associated origin. This is the first record of ESBL-producing enterobacteria from Antarctica.
Thermal Inactivation of Infectious Pancreatic Necrosis Virus in a Peptone-Salt Medium Mimicking the Water-Soluble Phase of Hydrolyzed Fish By-Products
Authors: Nygaard Halvor , Modahl Ingebjørg , Myrmel Mette 
Published: January 2012

ABSTRACT

Infectious pancreatic necrosis virus (IPNV) (serotype Sp) was exposed to temperatures between 60 and 90°C in a medium mimicking the water-soluble phase of hydrolyzed fish by-products.
D
values ranged from 290 to 0.5 min, and the
z
value was approximately 9.8°C. Addition of formic acid to create a pH 4 medium did not enhance heat inactivation. Predicted inactivation effects at different temperature-time combinations are provided.
Development of a Modified Gentamicin Resistance Cassette for Genetic Manipulation of the Oral Spirochete Treponema denticola
Authors: Bian Jiang , Fenno J. Christopher , Li Chunhao 
Published: January 2012

ABSTRACT

Herein, we report that a modified gentamicin cassette and a PCR-based method can be used for targeted mutagenesis of the oral spirochete
Treponema denticola
. This approach minimizes polar effects and spontaneous antibiotic resistance. Therefore, it can serve as a reliable tool for genetic manipulation of
T. denticola
.
Cathepsin B Inhibition Limits Bone Metastasis in Breast Cancer
Authors: Withana Nimali P. , Blum Galia , Sameni Mansoureh , Slaney Clare , Anbalagan Arulselvi , Olive Mary B. , Bidwell Bradley N. , Edgington Laura , Wang Ling , Moin Kamiar , Sloane Bonnie F. , Anderson Robin L. , Bogyo Matthew S. , Parker Belinda S. 
Published: January 2012

Abstract
Metastasis to bone is a major cause of morbidity in breast cancer patients, emphasizing the importance of identifying molecular drivers of bone metastasis for new therapeutic targets. The endogenous cysteine cathepsin inhibitor stefin A is a suppressor of breast cancer metastasis to bone that is coexpressed with cathepsin B in bone metastases. In this study, we used the immunocompetent 4T1.2 model of breast cancer which exhibits spontaneous bone metastasis to evaluate the function and therapeutic targeting potential of cathepsin B in this setting of advanced disease. Cathepsin B abundancy in the model mimicked human disease, both at the level of primary tumors and matched spinal metastases. RNA interference–mediated knockdown of cathepsin B in tumor cells reduced collagen I degradation in vitro and bone metastasis in vivo. Similarly, intraperitoneal administration of the highly selective cathepsin B inhibitor CA-074 reduced metastasis in tumor-bearing animals, a reduction that was not reproduced by the broad spectrum cysteine cathepsin inhibitor JPM-OEt. Notably, metastasis suppression by CA-074 was maintained in a late treatment setting, pointing to a role in metastatic outgrowth. Together, our findings established a prometastatic role for cathepsin B in distant metastasis and illustrated the therapeutic benefits of its selective inhibition in vivo. Cancer Res; 72(5); 1199–209. ©2012 AACR.
Infiltration of Lynch Colorectal Cancers by Activated Immune Cells Associates with Early Staging of the Primary Tumor and Absence of Lymph Node Metastases
Authors: de Miranda Noel F.C.C. , Goudkade Danny , Jordanova Ekaterina S. , Tops Carli M.J. , Hes Frederik J. , Vasen Hans F.A. , van Wezel Tom , Morreau Hans 
Published: January 2012

AbstractPurpose: Lynch syndrome colorectal cancers often lose human leukocyte antigen (HLA) class I expression. The outgrowth of clones with immune evasive phenotypes is thought to be positively selected by the action of cytotoxic T cells that target HLA class I–positive cancer cells. To investigate this hypothesis, we related the type and density of tumor lymphocytic infiltrate in Lynch colorectal cancers with their HLA class I phenotype and clinicopathologic stage.Experimental Design: HLA class I expression was assessed by means of immunohistochemistry. Characterization of tumor-infiltrating lymphocytes was carried out by using a triple immunofluorescence procedure that allowed the simultaneous detection of CD3-, CD8-, and granzyme B (GZMB)-positive cells. Additional markers were also used for further characterization of an elusive CD3−/CD8−/GZMB+ cell population.Results: We discovered that high tumor infiltration by activated CD8+ T cells correlated with aberrant HLA class I expression and associated with early tumor stages (P &lt; 0.05). CD8+ T cells were most abundant in HLA class I heterogeneous tumors (P = 0.02) and frequent in HLA class I–negative cases (P = 0.04) when compared with HLA class I–positive carcinomas. An elusive immune cell population (CD45+/CD8−/CD56−/GZMB+) was characteristic for HLA class I–negative tumors lacking lymph node metastases (P &lt; 0.01).Conclusions: The immune system assumes an important role in counteracting the progression of Lynch colorectal cancers and in selecting abnormal HLA class I phenotypes. Our findings support the development of clinical strategies that explore the natural antitumor immune responses occurring in Lynch syndrome carriers. Clin Cancer Res; 18(5); 1237–45. ©2012 AACR.
Association of β-Blocker Exposure With Outcomes in Heart Failure Differs Between African American and White Patients
Authors: Lanfear David E. , Hrobowski Tara N. , Peterson Edward L. , Wells Karen E. , Swadia Tanmay V. , Spertus John A. , Williams L. Keoki 
Published: January 2012

Background—
β-Blockers (BB) are a mainstay of heart failure (HF) treatment, yet there are inconclusive data regarding their efficacy in African American individuals.

Methods and Results—

We performed a retrospective study of insured patients who received care from a large health system who were hospitalized for HF between January 2000 and June 2008 and had a documented ejection fraction <50%. BB exposure was estimated over 6-month rolling windows, using pharmacy claims data. Proportional hazards regression was used to test the association between BB exposure and all-cause hospitalization or death with adjustment for baseline covariates and other HF medication exposure. We performed analyses stratified by race and overall with a BB exposure×race interaction term. A total of 1094 patients met inclusion criteria (476 white and 618 African American individuals). Median follow-up was 2.1 years. In adjusted models, BB exposure was associated with lower risk of death or hospitalization in both groups, but more so in white individuals (hazard ratio, 0.40; 95% confidence interval, 0.27, 0.60;
P
<0.001) compared with African American individuals (hazard ratio, 0.67; 95% confidence interval, 0.48, 0.94;
P
=0.024). A formal test for interaction indicated that the protection association for BB exposure differed by race (
P
=0.098, β=0.40). Reanalysis restricted to BBs approved for HF or HF-specific hospitalizations did not substantively alter the findings.

Conclusions—
BB appears to be 40–50% less effective in preventing death or hospitalization among African American patients with HF as compared with white individuals. Further study is needed to better understand BB effectiveness in African Americans with HF.
GABAA Agonist Reduces Visual Awareness: A Masking–EEG Experiment
Authors: van Loon Anouk M. , Scholte H. Steven , van Gaal Simon , van der Hoort Björn J. J. , Lamme Victor A. F. 
Published: January 2012

Abstract
Consciousness can be manipulated in many ways. Here, we seek to understand whether two such ways, visual masking and pharmacological intervention, share a common pathway in manipulating visual consciousness. We recorded EEG from human participants who performed a backward-masking task in which they had to detect a masked figure form its background (masking strength was varied across trials). In a within-subject design, participants received dextromethorphan (a N-methyl-d-aspartate receptor antagonist), lorazepam (LZP; a GABAA receptor agonist), scopolamine (a muscarine receptor antagonist), or placebo. The behavioral results show that detection rate decreased with increasing masking strength and that of all the drugs, only LZP induced a further decrease in detection rate. Figure-related ERP signals showed three neural events of interest: (1) an early posterior occipital and temporal generator (94–121 msec) that was not influenced by any pharmacological manipulation nor by masking, (2) a later bilateral perioccipital generator (156–211 msec) that was reduced by masking as well as LZP (but not by any other drugs), and (3) a late bilateral occipital temporal generator (293–387 msec) that was mainly affected by masking. Crucially, only the intermediate neural event correlated with detection performance. In combination with previous findings, these results suggest that LZP and masking both reduce visual awareness by means of modulating late activity in the visual cortex but leave early activation intact. These findings provide the first evidence for a common mechanism for these two distinct ways of manipulating consciousness.
Development and Evaluation of Mei-Yu Season Quantitative Precipitation Forecasts in Taiwan River Basins Based on a Conceptual Climatology Model
Authors: Wang Chung-Chieh , Kung Chu-Ying , Lee Cheng-Shang , Tai-Jen Chen George 
Published: January 2012

AbstractUsing rain gauge data during 134 mei-yu frontal cases in May–June 1991–2006, a rainfall climatology in relation to the positions of fronts every 0.5° in Taiwan is obtained, showing widespread precipitation with maxima over windward mountain slopes associated with frontal passages. For six major river basins, rainfall characteristics and synoptic factors are further analyzed to build a conceptual climatology model for short-term quantitative precipitation forecasts (QPFs). The four basins in central–southern Taiwan exhibit increased heavy-rainfall frequencies (&gt;25%) roughly from 2° south to 1° north of the front, while the two basins in northern Taiwan have lower frequencies with different characteristics mainly due to the differences in their topography. The synoptic factors in the checklist employed by the Central Weather Bureau and important to heavy rainfall are identified for each of the six basins through statistical tests and their threat score (TS). These factors include those related to mei-yu fronts, low-level jets and moisture, upper-level divergence–diffluence, and short-wave troughs. A conceptual climatology model that uses both synoptic and probability forecasting guidance is developed, and in practice the average rainfall climatology is replaced by one obtained for heavy-rainfall periods if either of the two guidance schemes indicates heavy-rainfall possibility. This model for 0–6- and 0–12-h QPFs is also evaluated for its usefulness using cases during the 2007–08 seasons. With typical TSs of 0.2–0.3 (for heavy rainfall), this approach outperforms simple climatology in all six basins especially toward higher thresholds (about 20–50 mm) and for 12-h events, where it also shows advantages over model QPFs in southern Taiwan. Thus, the model can provide useful information for operational use.
The potential of wood fibers as reinforcement in cellular biopolymers
Authors: Neagu R Cristian , Cuénoud Matthieu , Berthold Fredrik , Bourban Pierre-Etienne , Gamstedt E Kristofer , Lindström Mikael , Månson Jan-Anders E 
Published: January 2012

Wood fiber-reinforced polylactic acid composite foams have been successfully produced using supercritical carbon dioxide. The addition of fibers had a strong effect on microstructure of the foams. An increase in wood fiber content implied smaller average cell size and higher average cell wall thickness as estimated from image analysis of scanning electron microscopy micrographs. Addition of 10 wt% wood fibers seemed to be a limit to obtain foams, with the used processing conditions. The stiffness properties of the foams in compression improved upon addition of wood fibers. A significant increase of specific stiffness was achieved by adding 5–10 wt% wood fibers. It was shown that the stiffness was about 50% higher in the transverse direction for reinforced foams. The strength in the transverse direction increased for foams with unmodified wood fibers but decreased for foams with two types of treated wood fibers as compared with the strength of the pure polylactic acid foam of similar density. A butyl tetracarboxylic acid treatment followed by an additional surfactant treatment results in reduced wood fiber network-forming ability and reduced fiber–matrix adhesion. This contributes to the inferior observed strength properties in this study. The experimental stiffness was comparable with a superposed micromechanical model for a three-phase fiber-reinforced foam. The model shows that increasing the relative density, that is, the ratio of the density of the foam to the density of the composite material, by adding wood fibers results in a noteworthy increase in the transverse compression stiffness of the foams but only at relative density values above 0.2 for the used processing conditions in this study. The key factor for reinforcement is the relation between foam relative density and fiber volume fraction in the preform. The foaming conditions have to be adapted for each wood fiber content to obtain foams with the desired relative density.