bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Akt–FoxO3a–manganese superoxide dismutase pathway is involved in the regulation of oxidative stress in diabetic nephropathy
Authors: Lu Qian , Zhai Yunpeng , Cheng Qian , Liu Yaowu , Gao Xing , Zhang Ting , Wei Yaqin , Zhang Fan , Yin Xiaoxing 
Published: November 2012

New Findings
What is the central question of this study?Oxidative stress is known to play an important role in the development and progression of diabetic nephropathy. However, the mechanism of overproduction of reactive oxygen species (ROS) in high‐glucose conditions is not completely clear.
What is the main finding and its importance?We demonstrated that high‐glucose concentrations induced excessive production of ROS and stimulated the phosphoinositide 3‐kinase–Akt–FoxO3a signalling pathway via the upregulation of transforming growth factor‐β1, resulting in phosphorylation and inactivation of FoxO3a and a reduction in the expression of its target gene, FoxO3a‐dependent manganese superoxide dismutase, and then further excessive production of ROS.
Oxidative stress has been shown to play an important role in the development and progression of diabetic nephropathy, and the formation of reactive oxygen species (ROS) is a direct consequence of hyperglycaemia. We hypothesized that hyperglycaemia‐induced ROS can activate the transforming growth factor‐β1 (TGF‐β1)–phosphoinositide 3‐kinase (PI3K)–Akt–FoxO3a signalling pathway, negatively regulating expression of manganese superoxide dismutase (MnSOD), which promotes excessive ROS generation and accelerates the pathological process of diabetic nephropathy. In vitro, in rat mesangial cells, high glucose (30 mmol l−1), but not equimolar mannitol, stimulated ROS production, upregulated the levels of TGF‐β1, increased the phosphorylated Akt/total Akt and phosphorylated FoxO3a/total FoxO3a protein ratios, altered the subcellular localization of FoxO3a and reduced the levels of MnSOD expression. These high‐glucose‐induced changes further promoted the generation of ROS. In vivo, in db/db mice treated with an inhibitor of TGF‐β1 (SB431542) or PI3K (LY294002), the levels of phosphorylated Akt and phosphorylated FoxO3a in the kidney cortices were decreased, the level of MnSOD expression was increased and the level of the lipid peroxidation end‐product, malondialdehyde, was reduced. We conclude that overproduction of ROS induced by a high glucose concentration decreases the expression of MnSOD via the PI3K–Akt–FoxO3a pathway and further aggravates oxidative stress in diabetic nephropathy.
Carriage and Fecal Counts of Cefotaxime M-Producing Escherichia coli in Pigs: a Longitudinal Study
Authors: Hansen Katrine Hartung , Damborg Peter , Andreasen Margit , Nielsen Søren Saxmose , Guardabassi Luca 
Published: November 2012

ABSTRACT

Current knowledge on extended-spectrum beta-lactamases (ESBLs) in animals is based largely on cross-sectional studies and qualitative data. The aim of this longitudinal study was to elucidate carriage proportions and fecal counts of ESBL-producing
Escherichia coli
in pigs during the production cycle. At each of three ESBL-positive single-sited farrow-to-finisher pig farms (farms A, B, and C) included in the study, individual fecal samples were taken from 17 to 20 sows 1 week before farrowing and from 2 piglets of each sow's litter four times from birth to slaughter (as piglets, weaners, and finishers). Cefotaxime (CTX)-resistant coliforms in feces were counted on MacConkey agar containing 2 μg/ml CTX and characterized for the presence of ESBL-encoding genes by PCR and sequencing. CTX-M-positive pigs were detected in all age groups at farms A (
bla
CTX-M-9
group, compatible with
bla
CTX-M-14/17
) and B (
bla
CTX-M-1
group, compatible with
bla
CTX-M-1/61
), whereas only three weaners were positive at farm C (
bla
CTX-M-1
group, compatible with
bla
CTX-M-1/61
). A significant decrease in carriage was detected during the production cycle, with on average 50% carriage immediately after birth, 58% just before weaning, 29% during weaning, and 12% during finishing. The observed reduction in numbers of CTX-M-positive pigs was accompanied by a significant reduction in mean fecal counts of CTX-resistant coliforms from ∼10
7
CFU/g in piglets to ∼10
3
CFU/g in finishers (
P
< 0.001). These findings provide novel information about the epidemiology of ESBLs at the farm level and have important implications for assessments of risks of meat contamination during slaughter.
Characterization of Newcastle Disease Viruses in Wild and Domestic Birds in Luxembourg from 2006 to 2008
Authors: Snoeck Chantal J. , Marinelli Marianna , Charpentier Emilie , Sausy Aurélie , Conzemius Tom , Losch Serge , Muller Claude P. 
Published: November 2012

ABSTRACT
Newcastle disease virus (NDV) is one of the most important viral diseases of birds. Wild birds constitute a natural reservoir of low-virulence viruses, while poultry are the main reservoir of virulent strains. Exchange of virus between these reservoirs represents a risk for both bird populations. Samples from wild and domestic birds collected between 2006 and 2010 in Luxembourg were analyzed for NDV. Three similar avirulent genotype I strains were found in ducks during consecutive years, suggesting that the virus may have survived and spread locally. However, separate introductions cannot be excluded, because no recent complete F gene sequences of genotype I from other European countries are available. Detection of vaccine-like strains in wild waterbirds suggested the spread of vaccine strains, despite the nonvaccination policy in Luxembourg. Among domestic birds, only one chicken was positive for a genotype II strain differing from the LaSota vaccine and exhibiting a so-far-unrecognized fusion protein cleavage site of predicted low virulence. Three genotype VI strains from pigeons were the only virulent strains found. The circulation of NDV in wild and free-ranging domestic birds warrants continuous surveillance because of increased concern that low-virulence wild-bird viruses could become more virulent in domestic populations.
Molecular Analysis of Human and Canine Staphylococcus aureus Strains Reveals Distinct Extended-Host-Spectrum Genotypes Independent of Their Methicillin Resistance
Authors: Vincze S. , Stamm I. , Monecke S. , Kopp P. A. , Semmler T. , Wieler L. H. , Lübke-Becker A. , Walther B. 
Published: November 2012

ABSTRACT

Staphylococcus aureus
causes a wide range of infectious diseases in humans and various animal species. Although presumptive host-specific factors have been reported, certain genetic lineages seem to lack specific host tropism, infecting a broad range of hosts. Such Extended-Host-Spectrum Genotypes (EHSGs) have been described in canine infections, caused by common regional human methicillin-resistant
S. aureus
(MRSA) lineages. However, information is scarce about the occurrence of methicillin-susceptible
S. aureus
(MSSA) EHSGs. To gain deeper insight into EHSG MSSA and EHSG MRSA of human and canine origin, a comparative molecular study was carried out, including a convenience sample of 120 current
S. aureus
(70 MRSA and 50 MSSA) isolates obtained from infected dogs.
spa
typing revealed 48 different
spa
types belonging to 16 different multilocus sequence typing clonal complexes (MLST-CCs). Based on these results, we further compared a subset of canine (
n
= 48) and human (
n
= 14) strains, including isolates of clonal complexes CC5, CC22, CC8, CC398, CC15, CC45, and CC30 by macrorestriction (pulsed-field gel electrophoresis [PFGE]) and DNA-microarray analysis. None of the methods employed was able to differentiate between clusters of human and canine strains independently of their methicillin resistance. In contrast, DNA-microarray analysis revealed 79% of the 48 canine isolates as carriers of the bacteriophage-encoded human-specific immune evasion cluster (IEC). In conclusion, the high degree of similarity between human and canine
S. aureus
strains regardless of whether they are MRSA or MSSA envisions the existence of common genetic traits that enable these strains as EHSGs, challenging the concept of resistance-driven spillover of MRSA.
Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands
Authors: van der Wielen Paul W. J. J. , van der Kooij Dick 
Published: November 2012

ABSTRACT

The multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereas
Legionella pneumophila
,
Pseudomonas aeruginosa
,
Stenotrophomonas maltophilia
, and
Aspergillus fumigatus
were sporadically observed.
Mycobacterium avium
complex and
Acanthamoeba
spp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM and
S. maltophilia
, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or on
P. aeruginosa
- and
S. maltophilia
-positive samples. However,
L. pneumophila
was detected more often in water with AOC concentrations above 10 μg C liter
−1
than in water with AOC levels below 5 μg C liter
−1
. Finally, samples that contained
L. pneumophila
,
P. aeruginosa
, or
S. maltophilia
were more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.
Temperature- and Salinity-Decoupled Overproduction of Hydroxyectoine by Chromohalobacter salexigens
Authors: Rodríguez-Moya Javier , Argandoña Montserrat , Iglesias-Guerra Fernando , Nieto Joaquín J. , Vargas Carmen 
Published: November 2012

ABSTRACT

Hydroxyectoine overproduction by the natural producer
Chromohalobacter salexigens
is presented in this study. Genetically engineered strains were constructed that at low salinity coexpressed, in a vector derived from a native plasmid, the ectoine (
ectABC
) and hydroxyectoine (
ectD
) genes under the control of the
ectA
promoter, in a temperature-independent manner. Hydroxyectoine production was further improved by increasing the copies of
ectD
and using a
C. salexigens
genetic background unable to synthesize ectoines.
Comparative Genomic Analysis and Benzene, Toluene, Ethylbenzene, and
o
-,
m
-, and
p
-Xylene (BTEX) Degradation Pathways of Pseudoxanthomonas spadix BD-a59
Authors: Choi Eun Jin , Jin Hyun Mi , Lee Seung Hyeon , Math Renukaradhya K. , Madsen Eugene L. , Jeon Che Ok 
Published: November 2012

ABSTRACT

Pseudoxanthomonas spadix
BD-a59, isolated from gasoline-contaminated soil, has the ability to degrade all six BTEX (benzene, toluene, ethylbenzene, and
o
-,
m
-, and
p
-xylene) compounds. The genomic features of strain BD-a59 were analyzed bioinformatically and compared with those of another fully sequenced
Pseudoxanthomonas
strain,
P. suwonensis
11-1, which was isolated from cotton waste compost. The genome of strain BD-a59 differed from that of strain 11-1 in many characteristics, including the number of rRNA operons, dioxygenases, monooxygenases, genomic islands (GIs), and heavy metal resistance genes. A high abundance of phage integrases and GIs and the patterns in several other genetic measures (e.g., GC content, GC skew, Karlin signature, and clustered regularly interspaced short palindromic repeat [CRISPR] gene homology) indicated that strain BD-a59's genomic architecture may have been altered through horizontal gene transfers (HGT), phage attack, and genetic reshuffling during its evolutionary history. The genes for benzene/toluene, ethylbenzene, and xylene degradations were encoded on GI-9, -13, and -21, respectively, which suggests that they may have been acquired by HGT. We used bioinformatics to predict the biodegradation pathways of the six BTEX compounds, and these pathways were proved experimentally through the analysis of the intermediates of each BTEX compound using a gas chromatograph and mass spectrometry (GC-MS). The elevated abundances of dioxygenases, monooxygenases, and rRNA operons in strain BD-a59 (relative to strain 11-1), as well as other genomic characteristics, likely confer traits that enhance ecological fitness by enabling strain BD-a59 to degrade hydrocarbons in the soil environment.
Dynamics and Diversity of Escherichia coli in Animals and System Management of the Manure on a Commercial Farrow-to-Finish Pig Farm
Authors: Marchant Mauricio , Moreno Miguel A. 
Published: November 2012

ABSTRACT

The objective of this study was to determine the dynamics and diversity of
Escherichia coli
populations in animal and environmental lines of a commercial farrow-to-finish pig farm in Spain along a full production cycle (July 2008 to July 2009), with special attention to antimicrobial resistance and the presence of integrons. In the animal line, a total of 256 isolates were collected from pregnant sows (10 samples and 20 isolates), 1-week-old piglets (20 samples and 40 isolates), unweaned piglets (20 samples and 38 isolates), growers (20 samples and 40 isolates), and the finishers' floor pen (6 samples and 118 isolates); from the underfloor pits and farm slurry tank environmental lines, 100 and 119 isolates, respectively, were collected. Our results showed that
E. coli
populations in the pig fecal microbiota and in the farm environment are highly dynamic and show high levels of diversity. These issues have been proven through DNA-based typing data (repetitive extragenic palindromic PCR [REP-PCR]) and phenotypic typing data (antimicrobial resistance profile comprising 19 antimicrobials). Clustering of the sampling groups based on their REP-PCR typing results showed that the spatial features (the line) had a stronger weight than the temporal features (sampling week) for the clustering of
E. coli
populations; this weight was less significant when clustering was performed based on resistotypes. Among animals, finishers harbored an
E. coli
population different from those of the remaining animal populations studied, considering REP-PCR fingerprints and resistotypes. This population, the most important from a public health perspective, demonstrated the lowest levels of antimicrobial resistance and integron presence.
Systems Engineering of Tyrosine 195, Tyrosine 260, and Glutamine 265 in Cyclodextrin Glycosyltransferase from Paenibacillus macerans To Enhance Maltodextrin Specificity for 2-
O
-
d
-Glucopyranosyl-
l
-Ascorbic Acid Synthesis
Authors: Han Ruizhi , Liu Long , Shin Hyun-dong , Chen Rachel R. , Li Jianghua , Du Guocheng , Chen Jian 
Published: November 2012

ABSTRACT

In this work, the site saturation mutagenesis of tyrosine 195, tyrosine 260 and glutamine 265 in the cyclodextrin glycosyltransferase (CGTase) from
Paenibacillus macerans
was conducted to improve the specificity of CGTase for maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the synthesis of 2-
O
-
d
-glucopyranosyl-
l
-ascorbic acid (AA-2G). Specifically, the site-saturation mutagenesis of three sites—tyrosine 195, tyrosine 260, and glutamine 265—was performed, and it was found that the resulting mutants (containing the mutations Y195S [tyrosine → serine], Y260R [tyrosine → arginine], and Q265K [glutamine → lysine]) produced higher AA-2G yields than the wild type and the other mutant CGTases when maltodextrin was used as the glycosyl donor. Furthermore, double and triple mutations were introduced, and four mutants (containing Y195S/Y260R, Y195S/Q265K, Y260R/Q265K, and Y260R/Q265K/Y195S) were obtained and evaluated for the capacity to produce AA-2G. The Y260R/Q265K/Y195S triple mutant produced the highest titer of AA-2G at 1.92 g/liter, which was 60% higher than that (1.20 g/liter) produced by the wild-type CGTase. The kinetics analysis of AA-2G synthesis by the mutant CGTases confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, all seven mutants had lower cyclization activities and higher hydrolysis and disproportionation activities. Finally, the mechanism responsible for the enhanced substrate specificity was explored by structure modeling, which indicated that the enhancement of maltodextrin specificity may be related to the changes of hydrogen bonding interactions between the side chain of residue at the three positions (195, 260, and 265) and the substrate sugars. This work adds to our understanding of the synthesis of AA-2G and makes the Y260R/Q265K/Y195S mutant a good starting point for further development by protein engineering.
Characterization and Molecular Epidemiology of a Fungal Infection of Edible Crabs (Cancer pagurus) and Interaction of the Fungus with the Dinoflagellate Parasite Hematodinium
Authors: Smith Amanda L. , Hamilton Kristina M. , Hirschle Lucy , Wootton Emma C. , Vogan Claire L. , Pope Edward C. , Eastwood Daniel C. , Rowley Andrew F. 
Published: November 2012

ABSTRACT

This study reports on an emerging fungal disease of the edible crab,
Cancer pagurus
. Juvenile (prerecruit) crabs were found to be subject to this disease condition during the months of May to September at two intertidal sites in South Wales, United Kingdom. Histopathology revealed that the fungi overwhelm the host response in the tissues, leading to progressive septicemia. The causative agent of this infection was isolated and grown in pure culture and was identified as a member of the
Ophiocordyceps
clade by sequencing of the small subunit of the fungal ribosomal DNA (rDNA). Of the crabs naturally infected with the fungus, 94% had a coinfection with the parasitic dinoflagellate
Hematodinium
species. To determine if there was any interaction between the two disease-causing agents, apparently fungus-free crabs, both with and without natural
Hematodinium
infections, were challenged with the fungal isolate. The presence of
Hematodinium
caused a significant reduction in fungal multiplication in the hemocoel of the crabs in comparison to that in
Hematodinium
-free individuals. Histopathology of coinfected crabs showed a systemic multiplication of
Hematodinium
within host tissues, leading to a rapid death, while
Hematodinium
-free crabs experimentally infected with the fungal isolate died due to fungal sepsis (septicemia) with the same characteristic pathology as seen in natural infections.
Distribution of Clostridium botulinum Type E Strains in Nunavik, Northern Quebec, Canada
Authors: Leclair Daniel , Farber Jeffrey M. , Doidge Bill , Blanchfield Burke , Suppa Sandy , Pagotto Franco , Austin John W. 
Published: November 2012

ABSTRACT

The distribution and levels of
Clostridium botulinum
type E were determined from field sites used by Inuit hunters for butchering seals along the coast of Nunavik. The incidence rates of
C. botulinum
type E in shoreline soil along the coast were 0, 50, and 87.5% among samples tested for the Hudson Strait, Hudson Bay, and Ungava Bay regions, respectively. Spores were detected in seawater or coastal rock surfaces from 17.6% of butchering sites, almost all of which were located in southern Ungava Bay. Concentrations of
C. botulinum
type E along the Ungava Bay coast were significantly higher than on the coasts of Hudson Strait and Hudson Bay, with the highest concentrations (270 to 1,800/kg of sample) found near butchering sites located along the mouths of large rivers. The Koksoak River contained high levels of
C. botulinum
type E, with the highest median concentration (270/kg) found in sediments of the marine portion of the river.
C. botulinum
type E was found in the intestinal contents (4.4%) and skins (1.4%) of seals. A high genetic biodiversity of
C. botulinum
type E isolates was observed among the 21 butchering sites and their surroundings along the Nunavik coastline, with 83% of isolates (44/53) yielding distinct pulsed-field gel electrophoresis genotypes. Multiple sources of
C. botulinum
type E may be involved in the contamination of seal meat during butchering in this region, but the risk of contamination appears to be much higher from environmental sources along the shoreline of southern Ungava Bay and the sediments of the Koksoak River.
Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 Signaling Pathway in Response to Thermal Stress
Authors: Lam Woei C. , Gerik Kimberly J. , Lodge Jennifer K. 
Published: November 2012

ABSTRACT

To initiate and establish infection in mammals, the opportunistic fungal pathogen
Cryptococcus neoformans
must survive and thrive upon subjection to host temperature. Primary maintenance of cell integrity is controlled through the protein kinase C1 (PKC1) signaling pathway, which is regulated by a Rho1 GTPase in
Saccharomyces cerevisiae
. We identified three
C. neoformans
Rho GTPases, Rho1, Rho10, and Rho11, and have begun to elucidate their role in growth and activation of the PKC1 pathway in response to thermal stress. Western blot analysis revealed that heat shock of wild-type cells resulted in phosphorylation of Mpk1 mitogen-activated protein kinase (MAPK). Constitutive activation of Rho1 caused phosphorylation of Mpk1 independent of temperature, indicating its role in pathway regulation. A strain with a deletion of
RHO10
also displayed this constitutive Mpk1 phosphorylation phenotype, while one with a deletion of
RHO11
yielded phosphorylation similar to that of wild type. Surprisingly, like a
rho10
Δ strain, a strain with a deletion of both
RHO10
and
RHO11
displayed temperature sensitivity but mimicked wild-type phosphorylation, which suggests that Rho10 and Rho11 have coordinately regulated functions. Heat shock-induced Mpk1 phosphorylation also required the PKC1 pathway kinases Bck1 and Mkk2. However, Pkc1, thought to be the major regulatory kinase of the cell integrity pathway, was dispensable for this response. Together, our results argue that Rho proteins likely interact via downstream components of the PKC1 pathway or by alternative pathways to activate the cell integrity pathway in
C. neoformans
.
Chlorobaculum tepidum TLS Displays a Complex Transcriptional Response to Sulfide Addition
Authors: Eddie Brian J. , Hanson Thomas E. 
Published: November 2012

ABSTRACT

Chlorobaculum tepidum
is a green sulfur bacterium (GSB) that is a model system for phototrophic sulfur oxidation. Despite over 2 decades of research, conspicuous gaps exist in our understanding of its electron donor metabolism and regulation. RNA sequencing (RNA-seq) was used to provide a global picture of the
C. tepidum
transcriptome during growth on thiosulfate as the sole electron donor and at time points following the addition of sulfide to such a culture. Following sulfide addition, 121 to 150 protein-coding genes displayed significant changes in expression depending upon the time point. These changes included a rapid decrease in expression of thiosulfate and elemental sulfur oxidation genes. Genes and gene loci with increased expression included CT1087, encoding a sulfide:quinone oxidoreductase required for growth in high sulfide concentrations; a polysulfide reductase-like complex operon,
psrABC
(CT0496 to CT0494); and, surprisingly, a large cluster of genes involved in iron acquisition. Finally, two genes that are conserved as a cassette in anaerobic bacteria and archaea, CT1276 and CT1277, displayed a strong increase in expression. The CT1277 gene product contains a DNA-binding domain, suggesting a role for it in sulfide-dependent gene expression changes.