bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic expression of DKK1 protein in the process whereby Epimedium‐derived flavonoids up‐regulate osteogenic and down‐regulate adipogenic differentiation of bone marrow stromal cells in ovariectomized rats
Authors: Xu Ying‐xing , Xu Bing , Wu Cheng‐liang , Wu Yan , Tong Pei‐jian , Xiao Lu‐wei 
Published: April 2011

Objective:  To observe the dynamic expression of DKK1 protein in the process whereby Epimedium‐derived flavonoids (EFs) regulate the balance between osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats, and to provide experimental evidence for the mechanism of EFs in the treatment of postmenopausal osteoporosis.Methods:  Bone marrow stromal cells from ovariectomized rats were separated and cultivated in osteoinductive or liquid medium for 15 days in vitro. EFs (10 µg/mL) were applied to both cultures. Alkaline phosphatase (ALP) staining, ALP activity determination, Oil Red O staining and fluorescence quantitative polymerase chain reaction were used to determine the influence of EFs on osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats. Moreover, in order to explore the exact mechanism of EFs on osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats, enzyme linked immunosorbent assay was used to determine the dynamic expression of DKK1 protein in this process.Results:  EFs increased activity of ALP and mRNA expression of Runx2 (early osteoblast differentiation factor) and decreased mRNA expression of PPARγ‐2 (key factor of fat generation). Importantly, EFs down‐regulated expression of DKK1 protein in an osteogenic induction medium and inhibited up‐regulation of DKK1 protein in an adipogenic induction medium.Conclusion:  EFs regulate the balance between osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats by down‐regulating expression of DKK1 protein. This may be an important molecular mechanism of EFs in the context of treatment of postmenopausal osteoporosis.
An examination of hardiness throughout the sport injury process
Authors: Wadey Ross , Evans Lynne , Hanton Sheldon , Neil Rich 
Published: April 2011

Objectives. This primary objective of the study was to examine the direct and moderating effects of hardiness on the prediction of sport injury, and the direct and indirect effects of hardiness on athletes’ responses to injury.Design. This study employed a longitudinal methodological design. Specifically, the injury status of 694 asymptomatic participants was monitored for 2 years. From the original sample, 104 athletes subsequently became injured and then completed a number of questionnaires throughout their recovery.Methods. Logistic regression, Pearson product‐moment correlation and Preacher and Hayes's (2008) bootstrapping procedure were used to analyse the data.Results. Findings revealed a direct and moderating effect of hardiness on the prediction of injury. Hardiness was also found to positively correlate with desirable, and negatively correlate with undesirable post‐injury psychological responses and coping strategies throughout recovery. Finally, problem‐focused coping was found to mediate certain effects of hardiness on injured athletes’ psychological responses.Conclusions. These findings have important implications for practitioners who have a vested interest in the health and well‐being of those who participate in sport and exercise in terms of minimizing rates of injury occurrence and/or facilitating recovery from injury.
Design of a Test
Rig for Vibration Control of Oil Platforms Using Magneto-Rheological
Dampers
Authors: Karkoub Mansour , Lamont Lisa
Ann , El
Chaar Lana 
Published: April 2011

Abstract
Offshore steel structures are widely used around the world, e.g., in Gulf of Mexico, the Middle East, and the North Sea. These structures are costly to build, and any damage to them could be catastrophic financially and environmentally. There are many factors that could possibly affect the health of these steel structures, particularly hydrodynamic forces. These forces cause the structure to vibrate and in the long run could lead to fatigue failure. Therefore, measures have to be taken in order to prevent these structures from failing. Magneto-rheological (MR) dampers are proven as a feasible alternative to reducing structural vibrations. An experimental setup is built in our laboratory to improve the dynamic modeling of steel jacketlike structures and study the effectiveness of MR dampers in decreasing the hydrodynamically induced vibrations. The structure is analyzed theoretically and experimentally, and the results are presented here.
Impact of Recently Emerged Sterol 14α-Demethylase (CYP51) Variants of Mycosphaerella graminicola on Azole Fungicide Sensitivity
Authors: Cools Hans J. , Mullins Jonathan G. L. , Fraaije Bart A. , Parker Josie E. , Kelly Diane E. , Lucas John A. , Kelly Steven L. 
Published: April 2011

ABSTRACT

The progressive decline in the effectiveness of some azole fungicides in controlling
Mycosphaerella graminicola
, causal agent of the damaging
Septoria
leaf blotch disease of wheat, has been correlated with the selection and spread in the pathogen population of specific mutations in the
M. graminicola CYP51
(
MgCYP51
) gene encoding the azole target sterol 14α-demethylase. Recent studies have suggested that the emergence of novel MgCYP51 variants, often harboring substitution S524T, has contributed to a decrease in the efficacy of prothioconazole and epoxiconazole, the two currently most effective azole fungicides against
M. graminicola
. In this study, we establish which amino acid alterations in novel MgCYP51 variants have the greatest impact on azole sensitivity and protein function. We introduced individual and combinations of identified alterations by site-directed mutagenesis and functionally determined their impact on azole sensitivity by expression in a
Saccharomyces cerevisiae
mutant YUG37::
erg11
carrying a regulatable promoter controlling native
CYP51
expression. We demonstrate that substitution S524T confers decreased sensitivity to all azoles when introduced alone or in combination with Y461S. In addition, S524T restores the function in
S. cerevisiae
of MgCYP51 variants carrying the otherwise lethal alterations Y137F and V136A. Sensitivity tests of
S. cerevisiae
transformants expressing recently emerged MgCYP51 variants carrying combinations of alterations D134G, V136A, Y461S, and S524T reveal a substantial impact on sensitivity to the currently most widely used azoles, including epoxiconazole and prothioconazole. Finally, we exploit a recently developed model of the MgCYP51 protein to predict that the substantial structural changes caused by these novel combinations reduce azole interactions with critical residues in the binding cavity, thereby causing resistance.
Competing Formate- and Carbon Dioxide-Utilizing Prokaryotes in an Anoxic Methane-Emitting Fen Soil
Authors: Hunger Sindy , Schmidt Oliver , Hilgarth Maik , Horn Marcus A. , Kolb Steffen , Conrad Ralf , Drake Harold L. 
Published: April 2011

ABSTRACT

Methanogenesis in wetlands is dependent on intermediary substrates derived from the degradation of biopolymers. Formate is one such substrate and is stimulatory to methanogenesis and acetogenesis in anoxic microcosms of soil from the fen Schlöppnerbrunnen. Formate dissimilation also yields CO
2
as a potential secondary substrate. The objective of this study was to resolve potential differences between anaerobic formate- and CO
2
-utilizing prokaryotes of this fen by stable isotope probing. Anoxic soil microcosms were pulsed daily with low concentrations of [
13
C]formate or
13
CO
2
(i.e., [
13
C]bicarbonate). Taxa were evaluated by assessment of 16S rRNA genes,
mcrA
(encoding the alpha-subunit of methyl-coenzyme M reductase), and
fhs
(encoding formyltetrahydrofolate synthetase). Methanogens, acetogens, and formate-hydrogen lyase-containing taxa appeared to compete for formate. Genes affiliated with
Methanocellaceae
,
Methanobacteriaceae
,
Acetobacteraceae
, and
Rhodospirillaceae
were
13
C enriched (i.e., labeled) in [
13
C]formate treatments, whereas genes affiliated with
Methanosarcinaceae
,
Conexibacteraceae
, and
Solirubrobacteraceae
were labeled in
13
CO
2
treatments. [
13
C]acetate was enriched in [
13
C]formate treatments, but labeling of known acetogenic taxa was not detected. However, several phylotypes were affiliated with acetogen-containing taxa (e.g.,
Sporomusa
).
Methanosaetaceae
-affiliated methanogens appeared to participate in the consumption of acetate. Twelve and 58 family-level archaeal and bacterial 16S rRNA phylotypes, respectively, were detected, approximately half of which had no isolated representatives.
Crenarchaeota
constituted half of the detected archaeal 16S rRNA phylotypes. The results highlight the unresolved microbial diversity of the fen Schlöppnerbrunnen, suggest that differing taxa competed for the same substrate, and indicate that
Methanocellaceae
,
Methanobacteriaceae
,
Methanosarcinaceae
, and
Methanosaetaceae
were linked to the production of methane, but they do not clearly resolve the taxa responsible for the apparent conversion of formate to acetate.
Cryptic Aspergillus nidulans Antimicrobials
Authors: Giles Steve S. , Soukup Alexandra A. , Lauer Carrie , Shaaban Mona , Lin Alexander , Oakley Berl R. , Wang Clay C. C. , Keller Nancy P. 
Published: April 2011

ABSTRACT

Secondary metabolite (SM) production by fungi is hypothesized to provide some fitness attribute for the producing organisms. However, most SM clusters are “silent” when fungi are grown in traditional laboratory settings, and it is difficult to ascertain any function or activity of these SM cluster products. Recently, the creation of a chromatin remodeling mutant in
Aspergillus nidulans
induced activation of several cryptic SM gene clusters. Systematic testing of nine purified metabolites from this mutant identified an emodin derivate with efficacy against both human fungal pathogens (inhibiting both spore germination and hyphal growth) and several bacteria. The ability of catalase to diminish this antimicrobial activity implicates reactive oxygen species generation, specifically, the generation of hydrogen peroxide, as the mechanism of emodin hydroxyl activity.
Phosphotransferase System-Independent Glucose Utilization in Corynebacterium glutamicum by Inositol Permeases and Glucokinases
Authors: Lindner Steffen N. , Seibold Gerd M. , Henrich Alexander , Krämer Reinhard , Wendisch Volker F. 
Published: April 2011

ABSTRACT

Phosphoenolpyruvate-dependent glucose phosphorylation via the phosphotransferase system (PTS) is the major path of glucose uptake in
Corynebacterium glutamicum
, but some growth from glucose is retained in the absence of the PTS. The growth defect of a deletion mutant lacking the general PTS component HPr in glucose medium could be overcome by suppressor mutations leading to the high expression of inositol utilization genes or by the addition of inositol to the growth medium if a glucokinase is overproduced simultaneously. PTS-independent glucose uptake was shown to require at least one of the inositol transporters IolT1 and IolT2 as a mutant lacking IolT1, IolT2, and the PTS component HPr could not grow with glucose as the sole carbon source. Efficient glucose utilization in the absence of the PTS necessitated the overexpression of a glucokinase gene in addition to either
iolT1
or
iolT2
. IolT1 and IolT2 are low-affinity glucose permeases with

K
s

values of 2.8 and 1.9 mM, respectively. As glucose uptake and phosphorylation via the PTS differs from glucose uptake via IolT1 or IolT2 and phosphorylation via glucokinase by the requirement for phosphoenolpyruvate, the roles of the two pathways for
l
-lysine production were tested. The
l
-lysine yield by
C. glutamicum
DM1729, a rationally engineered
l
-lysine-producing strain, was lower than that by its PTS-deficient derivate DM1729Δ
hpr
, which, however, showed low production rates. The combined overexpression of
iolT1
or
iolT2
with
ppgK
, the gene for PolyP/ATP-dependent glucokinase, in DM1729Δ
hpr
enabled
l
-lysine production as fast as that by the parent strain DM1729 but with 10 to 20% higher
l
-lysine yield.
Life in the Cold: a Proteomic Study of Cold-Repressed Proteins in the Antarctic Bacterium Pseudoalteromonas haloplanktis TAC125
Authors: Piette Florence , D'Amico Salvino , Mazzucchelli Gabriel , Danchin Antoine , Leprince Pierre , Feller Georges 
Published: April 2011

ABSTRACT

The proteomes expressed at 4°C and 18°C by the psychrophilic Antarctic bacterium
Pseudoalteromonas haloplanktis
were compared using two-dimensional differential in-gel electrophoresis with special reference to proteins repressed by low temperatures. Remarkably, the major cold-repressed proteins, almost undetectable at 4°C, were heat shock proteins involved in folding assistance.
Isolation from Animal Tissue and Genetic Transformation of Coxiella burnetii Are Facilitated by an Improved Axenic Growth Medium
Authors: Omsland Anders , Beare Paul A. , Hill Joshua , Cockrell Diane C. , Howe Dale , Hansen Bryan , Samuel James E. , Heinzen Robert A. 
Published: April 2011

ABSTRACT

We recently described acidified citrate cysteine medium (ACCM), which supports host cell-free (axenic) growth of
Coxiella burnetii
. After 6 days of incubation, greater than 3 logs of growth was achieved with the avirulent Nine Mile phase II (NMII) strain. Here, we describe modified ACCM and culture conditions that support improved growth of
C. burnetii
and their use in genetic transformation and pathogen isolation from tissue samples. ACCM was modified by replacing fetal bovine serum with methyl-β-cyclodextrin to generate ACCM-2. Cultivation of NMII in ACCM-2 with moderate shaking and in 2.5% oxygen yielded 4 to 5 logs of growth over 7 days. Similar growth was achieved with the virulent Nine Mile phase I and G isolates of
C. burnetii
. Colonies that developed after 6 days of growth in ACCM-2 agarose were approximately 0.5 mm in diameter, roughly 5-fold larger than those formed in ACCM agarose. By electron microscopy, colonies consisted primarily of the
C. burnetii
small cell variant morphological form. NMII was successfully cultured in ACCM-2 when medium was inoculated with as little as 10 genome equivalents contained in tissue homogenates from infected SCID mice. A completely axenic
C. burnetii
genetic transformation system was developed using ACCM-2 that allowed isolation of transformants in about 2 1/2 weeks. Transformation experiments demonstrated clonal populations in colonies and a transformation frequency of approximately 5 × 10
−5
. Cultivation in ACCM-2 will accelerate development of
C. burnetii
genetic tools and provide a sensitive means of primary isolation of the pathogen from Q fever patients.
Immediate Reduction of Salmonella enterica Serotype Typhimurium Viability via Membrane Destabilization following Exposure to Multiple-Hurdle Treatments with Heated, Acidified Organic Acid Salt Solutions
Authors: Milillo S. R. , Martin E. , Muthaiyan A. , Ricke S. C. 
Published: April 2011

ABSTRACT

The antimicrobial activity of organic acids in combination with nonchemical treatments was evaluated for inactivation of
Salmonella enterica
serotype Typhimurium within 1 min. It was observed that the effectiveness of the multiple-hurdle treatments was temperature (
P
≤ 0.05) and pH (
P
≤ 0.05) dependent and corresponded to the degree of organic acid lipophilicity (sodium acetate being least effective and sodium propionate being the most effective). This led to the hypothesis that the loss in viability was due at least in part to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed treatment effects on the cell membrane. Interestingly, all treatments, even those with no effect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response of
S
. Typhimurium to sodium acetate and sodium propionate, the most similar of the tested treatments in terms of pK
a
and ionic strength, and found little difference in the changes in gene expression following exposure to either, despite their very different effects on viability. Taken together, the results reported support our hypothesis that treatment with heated, acidified, organic acid salt solutions for 1 min causes loss of
S
. Typhimurium viability at least in part by membrane damage and that the degree of effectiveness can be correlated with lipophilicity of the organic acid. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide an effective antimicrobial treatment against
Salmonella
.
Hpa2 Required by HrpF To Translocate Xanthomonas oryzae Transcriptional Activator-Like Effectors into Rice for Pathogenicity
Authors: Li Yu-Rong , Che Yi-Zhou , Zou Hua-Song , Cui Yi-Ping , Guo Wei , Zou Li-Fang , Biddle Eulandria M. , Yang Ching-Hong , Chen Gong-You 
Published: April 2011

ABSTRACT

Xanthomonas oryzae
pv. oryzicola, the causative agent of bacterial leaf streak, injects a plethora of effectors through the type III secretion system (T3SS) into rice cells to cause disease. The T3SS, encoded by the
hrp
genes, is essential for the pathogen to elicit the hypersensitive response (HR) in nonhost tobacco and for pathogenicity in host rice. Whether or not a putative lytic transglycosylase, Hpa2, interacts with a translocon protein, HrpF, to facilitate bacterial pathogenicity remains unknown. Here we demonstrated that both the
hpa2
and
hrpF
genes are required for the pathogenicity of
X. oryzae
pv. oryzicola strain RS105 in rice but not for HR induction in tobacco. The expression of
hpa2
was positively regulated by HrpG and HrpD6 but not by HrpX.
In vivo
secretion and subcellular localization analyses confirmed that Hpa2 secretion is dependent on HpaB (a T3SS exit protein) and that Hpa2 binds to the host cell membrane. Protein-protein assays demonstrated that Hpa2 interacts with HrpF.
In planta
translocation of AvrXa10 indicated that the mutation in
hpa2
and
hrpF
inhibits the injection of the HpaB-dependent transcriptional activator-like (TAL) effector into rice. These findings suggest that Hpa2 and HrpF form a complex to translocate T3S effectors into plant cells for pathogenesis in host rice.
Cocirculation of Two Transmission Lineages of Echovirus 6 in Jinan, China, as Revealed by Environmental Surveillance and Sequence Analysis
Authors: Tao Zexin , Wang Haiyan , Li Yan , Xu Aiqiang , Zhang Yong , Song Lizhi , Yoshida Hiromu , Xu Qing , Yang Jing , Zhang Yan , Liu Yao , Feng Lei , Xu Wenbo 
Published: April 2011

ABSTRACT

Enterovirus environmental surveillance on sewage from the city of Jinan, Shandong Province, China, was initiated in 2008. Thirty echovirus 6 (E6) strains—1 in 2008 and 29 in 2010—were isolated and identified. Most E6 isolates (
n
= 21) came from the sewage collected on August 2010, revealing high local E6 activity at that time. Interestingly, the VP1 sequences of most isolates, even from the same sewage, were not identical. Phylogenetic analysis of VP1 sequences revealed two lineages for these isolates, with 78.0 to 80.0% nucleotide identities with one another, 94.8 to 100.0% identity within the major lineage, and 92.7 to 98.5% identity within the minor one. The VP1 sequences of environmental isolates, clinical isolates from 1998 to 2010, and global E6 were subjected to evolutionary analysis using Bayesian phylodynamic methods. The inferred E6 VP1 ancestral sequence dated back to 1901 (range, 1873 to 1928) and evolved with 7.047 × 10
−3
substitutions per site per year. Shandong E6 segregated into three clusters, and the two environmental lineages belonged to clusters A and C, which originated in 2003 and 1992, respectively. The antigenicity analysis via neutralization assay confirmed great antigenic differences between Shandong isolates and a prototype strain. These findings underscore the value of continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses in the population and give further insight into E6 evolution.
The F-Box Protein Fbp1 Regulates Sexual Reproduction and Virulence in Cryptococcus neoformans
Authors: Liu Tong-Bao , Wang Yina , Stukes Sabriya , Chen Qing , Casadevall Arturo , Xue Chaoyang 
Published: April 2011

ABSTRACTCryptococcus neoformansis the leading cause of fungal meningitis in immunocomprised populations. Although extensive studies have been conducted on signal transduction pathways important for fungal sexual reproduction and virulence, how fungal virulence is regulated during infection is still not understood. In this study, we identified the F-box protein Fbp1, which contains a putative F-box domain and 12 leucine-rich repeats (LRR). Althoughfbp1mutants showed normal growth and produced normal major virulence factors, such as melanin and capsule, Fbp1 was found to be essential for fungal virulence, asfbp1mutants were avirulent in a murine systemic-infection model. Fbp1 is also important for fungal sexual reproduction. Basidiospore production was blocked in bilateral mating betweenfbp1mutants, even though normal dikaryotic hyphae were observed during mating.In vitroassays of stress responses revealed thatfbp1mutants are hypersensitive to SDS, but not calcofluor white (CFW) or Congo red, indicating that Fbp1 may regulate cell membrane integrity. Fbp1 physically interacts with Skp1 homologues in bothSaccharomyces cerevisiaeandC. neoformansvia its F-box domain, suggesting it may function as part of an SCF (Skp1, Cullins, F-box proteins) E3 ligase. Overall, our study revealed that the F-box protein Fbp1 is essential for fungal sporulation and virulence inC. neoformans, which likely represents a conserved novel virulence control mechanism that involves the SCF E3 ubiquitin ligase-mediated proteolysis pathway.
Targeted Gene Deletion and
In Vivo
Analysis of Putative Virulence Gene Function in the Pathogenic Dermatophyte Arthroderma benhamiae
Authors: Grumbt Maria , Defaweux Valérie , Mignon Bernard , Monod Michel , Burmester Anke , Wöstemeyer Johannes , Staib Peter 
Published: April 2011

ABSTRACT

Dermatophytes cause the majority of superficial mycoses in humans and animals. However, little is known about the pathogenicity of this specialized group of filamentous fungi, for which molecular research has been limited thus far. During experimental infection of guinea pigs by the human pathogenic dermatophyte
Arthroderma benhamiae
, we recently detected the activation of the fungal gene encoding malate synthase AcuE, a key enzyme of the glyoxylate cycle. By the establishment of the first genetic system for
A. benhamiae
, specific Δ
acuE
mutants were constructed in a wild-type strain and, in addition, in a derivative in which we inactivated the nonhomologous end-joining pathway by deletion of the
A. benhamiae KU70
gene. The absence of Aben
KU70
resulted in an increased frequency of the targeted insertion of linear DNA by homologous recombination, without notably altering the monitored
in vitro
growth abilities of the fungus or its virulence in a guinea pig infection model. Phenotypic analyses of Δ
acuE
mutants and complemented strains depicted that malate synthase is required for the growth of
A. benhamiae
on lipids, major constituents of the skin. However, mutant analysis did not reveal a pathogenic role of the
A. benhamiae
enzyme in guinea pig dermatophytosis or during epidermal invasion of the fungus in an
in vitro
model of reconstituted human epidermis. The presented efficient system for targeted genetic manipulation in
A. benhamiae
, paired with the analyzed infection models, will advance the functional characterization of putative virulence determinants in medically important dermatophytes.