bluuebunny/crossref_metadata_2025_split huggingface dataset:
Welfare states, families, job attribute preferences, and work
Authors: Corrigall Elizabeth A. 
Published: May 2008

PurposeThis paper aims to examine the relationship between welfare state configurations, family status, family responsibilities, job attribute preferences, employment, and weekly paid work hours.Design/methodology/approachInternational data for women and men were analyzed separately using regressions to determine if different welfare state configurations and individual family status and responsibilities predicted job attribute preferences. Additional regressions examined the effects of welfare state configurations, family status, family responsibilities, and job attribute preferences on women's and men's employment and weekly paid work hours.FindingsIn many cases, the variables were significant predictors of women's and men's job attribute preferences, employment and paid work hours.Practical implicationsWhile the attributes that people seek from their employment vary from individual to individual, it is also important to recognize that there are cultural patterns that can inform motivational efforts.Originality/valueThis multinational study is the first to examine the relationship between family status, conducting housework, providing family income, and job attribute preferences while considering labor market opportunities for women and societal support for the family. In addition, it examines the effects of these variables on employment and weekly paid work hours.
Interest mining in virtual learning environments
Authors: Gu Rong , Zhu Miaoliang , Zhao Liying , Zhang Ningning 
Published: May 2008

PurposeBehaviour in virtual learning environments (VLE), including travel, gaze, manipulate, gesture and conversation, offer considerable information about the user's implicit interest. The purpose of this study is to find an approach for user interest mining via behaviour analysis in a VLE.Design/methodology/approachAccording to research in psychology, any interaction in a VLE has implications for the user's implicit interest. In order to mine a user's implicit interest, an explicit interaction‐interest model needs to be established. This paper presents findings from the concept classification of behaviour in a VLE. Based on this classification, the paper proposes a hierarchical interaction model. In this model the relation between interaction and user interest can be described and used to improve system performance.FindingsIn the experimental prototype the authors found that user‐implicit interest could be mined via stages of web mining, i.e. capture the user's original gesture signal, data pre‐process, pattern discovery, interaction goal and interest mining. The mined user's interest information can be used to update the state of local interest, leading to a reduction in network traffic and promotion of better system performance.Originality/valueThis is an original study using behaviour analysis for interest mining in e‐learning. Research on interest mining in e‐learning focused on content mining or search engine and usage mining in web courses. The paper provides valuable clues regarding user interest mining in a VLE, in which the context is different from usual web courses. The research output can be implemented widely, including online learning, and especially in the VLE.
Supporting partner identification for virtual organisations in manufacturing
Authors: Hans Carl 
Published: May 2008

PurposeVirtual organisations (VOs) in manufacturing represent a promising approach for dealing with today's difficult markets. The selection of the right partners during the creation phase is a prerequisite for their success. Owing to the complexity of the underlying networks as well as the need to react immediately to market opportunities, tool support is necessary for finding a suitable consortia for a given business purpose while reducing the immanent risk of failure. The purpose of this paper is to exemplify the conception and realisation of such a tool.Design/methodology/approachThe approach taken in this work consists of four steps: first of all, the requirements to be fulfilled by the tool are derived from the main characteristics of VOs. Subsequently, existing approaches which could serve as a technical basis for the tool are presented and ranked. To conclude, a tool design is introduced and applied to a brief case study.FindingsIt is shown that simulation appears as very suitable within the considered problem domain. It is further pointed out that simulation requires user‐friendly components addressing modelling, simulation execution and analysis in order to be applicable and accepted by domain experts as end‐users.Originality/valueThe paper presents an overview of technical approaches supporting partner identification during the establishment phase of VOs. It describes a concept for a simulation environment addressing the needs of practitioners from industry. Finally, it depicts necessary extensions for model verification and solution finding.
The Extracellular Metalloprotease ofVibrio tubiashiiIs a Major Virulence Factor for Pacific Oyster (Crassostrea gigas) Larvae
Authors: Hasegawa Hiroaki , Lind Erin J. , Boin Markus A. , Häse Claudia C. 
Published: May 2008

ABSTRACTVibrio tubiashiiis a recently reemerging pathogen of larval bivalve mollusks, causing both toxigenic and invasive disease. MarineVibriospp. produce an array of extracellular products as potential pathogenicity factors. Culture supernatants ofV. tubiashiihave been shown to be toxic to oyster larvae and were reported to contain a metalloprotease and a cytolysin/hemolysin. However, the structural genes responsible for these proteins have yet to be identified, and it is uncertain which extracellular products play a role in pathogenicity. We investigated the effects of the metalloprotease and hemolysin secreted byV. tubiashiion its ability to kill Pacific oyster (Crassostrea gigas) larvae. WhileV. tubiashiisupernatants treated with metalloprotease inhibitors severely reduced the toxicity to oyster larvae, inhibition of the hemolytic activity did not affect larval toxicity. We identified structural genes ofV. tubiashiiencoding a metalloprotease (vtpA) and a hemolysin (vthA). Sequence analyses revealed that VtpA shared high homology with metalloproteases from a variety ofVibriospecies, while VthA showed high homology only to the cytolysin/hemolysin ofVibrio vulnificus. Compared to the wild-type strain, a VtpA mutant ofV. tubiashiinot only produced reduced amounts of protease but also showed decreased toxicity toC. gigaslarvae.Vibrio choleraestrains carrying thevtpAorvthAgene successfully secreted the heterologous protein. Culture supernatants ofV. choleraecarryingvtpAbut notvthAwere highly toxic to Pacific oyster larvae. Together, these results suggest that theV. tubiashiiextracellular metalloprotease is important in its pathogenicity toC. gigaslarvae.
Insights into the Mode of Action of Chitosan as an Antibacterial Compound
Authors: Raafat Dina , von Bargen Kristine , Haas Albert , Sahl Hans-Georg 
Published: May 2008

ABSTRACTChitosan is a polysaccharide biopolymer that combines a unique set of versatile physicochemical and biological characteristics which allow for a wide range of applications. Although its antimicrobial activity is well documented, its mode of action has hitherto remained only vaguely defined. In this work we investigated the antimicrobial mode of action of chitosan using a combination of approaches, including in vitro assays, killing kinetics, cellular leakage measurements, membrane potential estimations, and electron microscopy, in addition to transcriptional response analysis. Chitosan, whose antimicrobial activity was influenced by several factors, exhibited a dose-dependent growth-inhibitory effect. A simultaneous permeabilization of the cell membrane to small cellular components, coupled to a significant membrane depolarization, was detected. A concomitant interference with cell wall biosynthesis was not observed. Chitosan treatment ofStaphylococcus simulans22 cells did not give rise to cell wall lysis; the cell membrane also remained intact. Analysis of transcriptional response data revealed that chitosan treatment leads to multiple changes in the expression profiles ofStaphylococcus aureusSG511 genes involved in the regulation of stress and autolysis, as well as genes associated with energy metabolism. Finally, a possible mechanism for chitosan's activity is postulated. Although we contend that there might not be a single classical target that would explain chitosan's antimicrobial action, we speculate that binding of chitosan to teichoic acids, coupled with a potential extraction of membrane lipids (predominantly lipoteichoic acid) results in a sequence of events, ultimately leading to bacterial death.
Microbial Communities in Contaminated Sediments, Associated with Bioremediation of Uranium to Submicromolar Levels
Authors: Cardenas Erick , Wu Wei-Min , Leigh Mary Beth , Carley Jack , Carroll Sue , Gentry Terry , Luo Jian , Watson David , Gu Baohua , Ginder-Vogel Matthew , Kitanidis Peter K. , Jardine Philip M. , Zhou Jizhong , Criddle Craig S. , Marsh Terence L. , Tiedje James M. 
Published: May 2008

ABSTRACT

Microbial enumeration, 16S rRNA gene clone libraries, and chemical analysis were used to evaluate the in situ biological reduction and immobilization of uranium(VI) in a long-term experiment (more than 2 years) conducted at a highly uranium-contaminated site (up to 60 mg/liter and 800 mg/kg solids) of the U.S. Department of Energy in Oak Ridge, TN. Bioreduction was achieved by conditioning groundwater above ground and then stimulating growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria in situ through weekly injection of ethanol into the subsurface. After nearly 2 years of intermittent injection of ethanol, aqueous U levels fell below the U.S. Environmental Protection Agency maximum contaminant level for drinking water and groundwater (<30 μg/liter or 0.126 μM). Sediment microbial communities from the treatment zone were compared with those from a control well without biostimulation. Most-probable-number estimations indicated that microorganisms implicated in bioremediation accumulated in the sediments of the treatment zone but were either absent or in very low numbers in an untreated control area. Organisms belonging to genera known to include U(VI) reducers were detected, including
Desulfovibrio, Geobacter, Anaeromyxobacter, Desulfosporosinus
, and
Acidovorax
spp. The predominant sulfate-reducing bacterial species were
Desulfovibrio
spp., while the iron reducers were represented by
Ferribacterium
spp. and
Geothrix
spp. Diversity-based clustering revealed differences between treated and untreated zones and also within samples of the treated area. Spatial differences in community structure within the treatment zone were likely related to the hydraulic pathway and to electron donor metabolism during biostimulation.
Assessment of Gut Bacteria for a Paratransgenic Approach To Control
Dermolepida albohirtum
Larvae
Authors: Pittman Geoffrey W. , Brumbley Stevens M. , Allsopp Peter G. , O'Neill Scott L. 
Published: May 2008

ABSTRACT

Bacteria from the hindguts of
Dermolepida albohirtum
larvae were assessed for their potential to be used in paratransgenic strategies that target scarab pests of sugarcane. Bacteria isolated in pure culture from the hindguts of
D. albohirtum
larvae were from the
Proteobacteria
,
Firmicutes
, and
Actinobacteria
phyla and matched closely with taxa from intestinal and rhizosphere environments. However, these isolates were not the most common gut-associated bacteria identified in denaturing gradient gel electrophoresis (DGGE) hindgut profiles. Subsequently, eight species of gut bacteria were fed to larvae, and RNA-based DGGE analysis of 16S rRNA was used to detect the persistence of these isolates in the hindgut environment. One of these isolates (Da-11) remained metabolically active in the hindgut for 19 days postconsumption. Da-11 most likely forms a new genus within the
Burkholderiales
order, along with taxa independently identified from larvae of the European scarab pest,
Melolontha melolontha
. Using the EZ::Tn
5
transposon system, a kanamycin resistance gene was inserted into the chromosome of Da-11, thus establishing a stable transformation technique for this species. A second feeding trial that included inoculating approximately 400 transgenic Da-11 cells onto a food source resulted in a density of 1 × 10
6
transgenic Da-11 cells/ml in the hindguts of larvae at 9 days postconsumption. These populations were maintained in the hindgut for at least another 12 days. The successful isolation, genetic transformation, and establishment of transgenic Da-11 cells in the hindguts of
D. albohirtum
larvae fulfill fundamental requirements for the future development of a paratransgenic approach to control scarab pests of sugarcane.
Functional Characterization of CgCTR2, a Putative Vacuole Copper Transporter That Is Involved in Germination and Pathogenicity inColletotrichum gloeosporioides
Authors: Barhoom Sima , Kupiec Martin , Zhao Xinhua , Xu Jin-Rong , Sharon Amir 
Published: May 2008

ABSTRACTCopper is a cofactor and transition metal involved in redox reactions that are essential in all eukaryotes. Here, we report that a vacuolar copper transporter that is highly expressed in resting spores is involved in germination and pathogenicity in the plant pathogenColletotrichum gloeosporioides. A screen ofC. gloeosporioidestransformants obtained by means of a promoterless green fluorescent protein (GFP) construct led to the identification of transformant N159 in which GFP signal was observed in spores. The transforming vector was inserted 70 bp upstream of a putative gene with homology to theSaccharomyces cerevisiaevacuolar copper transporter geneCTR2. TheC. gloeosporioides CTR2(CgCTR2) gene fully complemented growth defects of yeastctr2Δ mutants, and a CgCTR2-cyan fluorescent protein (CFP) fusion protein accumulated in vacuole membranes, confirming the function of the protein as a vacuolar copper transporter. Expression analysis indicated that CgCTR2transcript is abundant in resting conidia and during germination in rich medium and downregulated during “pathogenic” germination and the early stages of plant infection. CgCTR2overexpression and silencing mutants were generated and characterized. The Cgctr2mutants had markedly reduced Cu superoxide dismutase (SOD) activity, suggesting that CgCTR2 is important in providing copper to copper-dependent cytosolic activities. The Cgctr2-silenced mutants had increased sensitivity to H2O2and reduced germination rates. The mutants were also less virulent to plants, but they did not display any defects in appressorium formation and penetration efficiency. An external copper supply compensated for the hypersensitivity to H2O2but not for the germination and pathogenicity defects of the mutants. Similarly, overexpression of CgCTR2enhanced resistance to H2O2but had no effect on germination or pathogenicity. Our results show that copper is necessary for optimal germination and pathogenicity and that CgCTR2 is involved in regulating cellular copper balance during these processes.
Mutagenesis of theShigella flexneriAutotransporter IcsA Reveals Novel Functional Regions Involved in IcsA Biogenesis and Recruitment of Host Neural Wiscott-Aldrich Syndrome Protein
Authors: May Kerrie L. , Morona Renato 
Published: May 2008

ABSTRACTThe IcsA (VirG) protein ofShigella flexneriis a polarly localized, outer membrane protein that is essential for virulence. Within host cells, IcsA activates the host actin regulatory protein, neural Wiskott-Aldrich syndrome protein (N-WASP), which in turn recruits the Arp2/3 complex, which nucleates host actin to form F-actin comet tails and initiate bacterial motility. Linker insertion mutagenesis was undertaken to randomly introduce 5-amino-acid in-frame insertions within IcsA. Forty-seven linker insertion mutants were isolated and expressed inS. flexneriΔicsAstrains. Mutants were characterized for IcsA protein production, cell surface expression and localization, intercellular spreading, F-actin comet tail formation, and N-WASP recruitment. Using this approach, we have identified a putative autochaperone region required for IcsA biogenesis, and our data suggest an additional region, not previously identified, is required for N-WASP recruitment.
Cortex Peptidoglycan Lytic Activity in Germinating
Bacillus anthracis
Spores
Authors: Dowd Melissa M. , Orsburn Benjamin , Popham David L. 
Published: May 2008

ABSTRACT

Bacterial endospore dormancy and resistance properties depend on the relative dehydration of the spore core, which is maintained by the spore membrane and its surrounding cortex peptidoglycan wall. During spore germination, the cortex peptidoglycan is rapidly hydrolyzed by lytic enzymes packaged into the dormant spore. The peptidoglycan structures in both dormant and germinating
Bacillus anthracis
Sterne spores were analyzed. The
B. anthracis
dormant spore peptidoglycan was similar to that found in other species. During germination,
B. anthracis
released peptidoglycan fragments into the surrounding medium more quickly than some other species. A major lytic enzymatic activity was a glucosaminidase, probably YaaH, that cleaved between
N
-acetylglucosamine and muramic-δ-lactam. An epimerase activity previously proposed to function on spore peptidoglycan was not detected, and it is proposed that glucosaminidase products were previously misidentified as epimerase products. Spore cortex lytic enzymes and their regulators are attractive targets for development of germination inhibitors to kill spores and for development of activators to cause loss of resistance properties for decontamination of spore release sites.
Omp85
Tt
from
Thermus thermophilus
HB27: an Ancestral Type of the Omp85 Protein Family
Authors: Nesper Jutta , Brosig Alexander , Ringler Philippe , Patel Geetika J. , Müller Shirley A. , Kleinschmidt Jörg H. , Boos Winfried , Diederichs Kay , Welte Wolfram 
Published: May 2008

ABSTRACT

Proteins belonging to the Omp85 family are involved in the assembly of β-barrel outer membrane proteins or in the translocation of proteins across the outer membrane in bacteria, mitochondria, and chloroplasts. The cell envelope of the thermophilic bacterium
Thermus thermophilus
HB27 is multilayered, including an outer membrane that is not well characterized. Neither the precise lipid composition nor much about integral membrane proteins is known. The genome of HB27 encodes one Omp85-like protein, Omp85
Tt
, representing an ancestral type of this family. We overexpressed Omp85
Tt
in
T. thermophilus
and purified it from the native outer membranes. In the presence of detergent, purified Omp85
Tt
existed mainly as a monomer, composed of two stable protease-resistant modules. Circular dichroism spectroscopy indicated predominantly β-sheet secondary structure. Electron microscopy of negatively stained lipid-embedded Omp85
Tt
revealed ring-like structures with a central cavity of ∼1.5 nm in diameter. Single-channel conductance recordings indicated that Omp85
Tt
forms ion channels with two different conducting states, characterized by conductances of ∼0.4 nS and ∼0.65 nS, respectively.
Functional Analysis of the Essential GTP-Binding-Protein-Coding GenecgtAofVibrio cholerae
Authors: Shah Sangita , Das Bhabatosh , Bhadra Rupak K. 
Published: May 2008

ABSTRACTThecgtAgene, coding for the conserved G protein CgtA, is essential in bacteria. In contrast to a previous report, here we show by using genetic analysis thatcgtAis essential inVibrio choleraeeven in a ΔrelAbackground. Depletion of CgtA affected the growth ofV. choleraeand rendered the cells highly sensitive to the replication inhibitor hydroxyurea. Overexpression ofV. choleraeCgtA caused distinct elongation ofEscherichia colicells. Deletion analysis indicated that the C-terminal end of CgtA plays a critical role in its proper function.
Stress anisotropy and wave propagation: a micromechanical view
Authors: Santamarina J C , Cascante G 
Published: May 2008

Wave propagation is a constant-fabric macrophenomenon, suitable to microinterpretation. Both velocity and attenuation characterize state, including inherent and stress-induced anisotropy. The purpose of this research is to study the effect of isotropic and deviatoric stresses on wave propagation in particulate materials at low strains and to interpret results at the microlevel. A resonant-column device was midified to allow for the application of axial extension and axial compression deviatoric loading. The fixed-free boundary condition of the sample was maintained. Data for round, hard-grained sand show that shear wave velocity and attenuation are primarily dependent on the mean stress on the polarization plane, with minimal effect of the deviatoric component, in agreement with prior observations at stress ratios less than 23. Attenuation is strongly correlated with the mean stress in the polarization plane and the level of shear strain. Damping does not vanish at low strains, contrary to predictions based on hysteretic behaviour; hence, other loss mechanisms must take place at low strains. Low-strain wave parameters are adequately corrected for mid-strain using modified hyperbolic models. Measured velocity and damping trends during isotropic and anisotropic loading qualitatively agree with predictions based on regular arrays. Key words: mechanical waves, resonant column, damping, shear modulus, stress anisotropy, random vibration.
Three-dimensional stability analysis for slurry-filled trench wall in cohesionless soil
Authors: Tsai Jiin-Song , Chang Jia-Chyi 
Published: May 2008

On the basis of the limiting equilibrium and arching theory, a three-dimensional analysis is proposed for slurry-supported trenches in cohesionless soils. This analytical approach is developed by considering the trench stability problem as a vertical soil cut within a fictitious half-silo with a rough wall surronding. Arching effects are considered not only in the vertical direction but also in the horizontal direction. A shell-shaped slip surface of the sliding soil mass is defined by Mohr-Coulomb criterion. The factor of safety is defines as the ratio of the resisting force induced by slurry pressure to the horizontal force required to maintain the stability of the trench wall. Results of the proposed method have been compared with those of two existing analytical methods for a typical trench stability problem. Key words: stability analysis, slurry trench wall, cohesionless soil.