bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of dopaminergic neuron firing by heterogeneous dopamine autoreceptors in the substantia nigra pars compacta
Authors: Jang Jin Young , Jang Miae , Kim Shin Hye , Um Ki Bum , Kang Yun Kyung , Kim Hyun Jin , Chung Sungkwon , Park Myoung Kyu 
Published: November 2010

J. Neurochem.(2011)116, 966–974.AbstractDopamine (DA) receptors generate many cellular signals and play various roles in locomotion, motivation, hormone production, and drug abuse. According to the location and expression types of the receptors in the brain, DA signals act in either stimulatory or inhibitory manners. Although DA autoreceptors in the substantia nigra pars compacta are known to regulate firing activity, the exact expression patterns and roles of DA autoreceptor types on the firing activity are highly debated. Therefore, we performed individual correlation studies between firing activity and receptor expression patterns using acutely isolated rat substantia nigra pars compacta DA neurons. When we performed single‐cell RT‐PCR experiments, D1, D2S, D2L, D3, and D5receptor mRNA were heterogeneously expressed in the order of D2L > D2S > D3 > D5 > D1. Stimulation of D2receptors with quinpirole suppressed spontaneous firing similarly among all neurons expressing mRNA solely for D2S, D2L, or D3receptors. However, quinpirole most strongly suppressed spontaneous firing in the neurons expressing mRNA for both D2and D3receptors. These data suggest that D2S, D2L, and D3receptors are able to equally suppress firing activity, but that D2and D3receptors synergistically suppress firing. This diversity in DA autoreceptors could explain the various actions of DA in the brain.
Pyrosequencing of the Genital Microbiotas of HIV-Seropositive and -Seronegative Women Reveals
Lactobacillus iners
as the Predominant
Lactobacillus
Species
Authors: Spear Gregory T. , Gilbert Douglas , Landay Alan L. , Zariffard Reza , French Audrey L. , Patel Pranjal , Gillevet Patrick M. 
Published: November 2010

ABSTRACT

The species of vaginal lactobacilli in HIV-seropositive and -seronegative women were determined by 16S gene pyrosequencing.
Lactobacillus iners
sequences were the predominant lactobacillus sequences in 66% of HIV
+
women and 90% of HIV
−
women. This has implications for resistance of HIV
+
and HIV
−
women to genital colonization by pathogenic organisms.
Effects of Ionic Strength on Bacteriophage MS2 Behavior and Their Implications for the Assessment of Virus Retention by Ultrafiltration Membranes
Authors: Furiga Aurelie , Pierre Gwenaelle , Glories Marie , Aimar Pierre , Roques Christine , Causserand Christel , Berge Mathieu 
Published: November 2010

ABSTRACT
Bacteriophage MS2 is widely used as a surrogate to estimate pathogenic virus elimination by membrane filtration processes used in water treatment. Given that this water technology may be conducted with different types of waters, we focused on investigating the effects of ionic strength on MS2 behavior. For this, MS2 was analyzed while suspended in solutions of various ionic strengths, first in a batch experiment and second during membrane ultrafiltration, and quantified using (i) quantitative reverse transcriptase PCR (qRT-PCR), which detects the total number of viral genomes, (ii) qRT-PCR without the RNA extraction step, which reflects only particles with a broken capsid (free RNA), and (iii) the PFU method, which detects only infectious viruses. At the beginning of the batch experiments using solutions containing small amounts of salts, losses of MS2 infectivity (90%) and broken particles (20%) were observed; these proportions did not change during filtration. In contrast, in high-ionic-strength solutions, bacteriophage kept its biological activity under static conditions, but it quickly lost its infectivity during the filtration process. Increasing the ionic strength decreased both the inactivation and the capsid breakup in the feed suspension and increased the loss of infectivity in the filtration retentate, while the numbers of MS2 genomes were identical in both experiments. In conclusion, the effects of ionic strength on MS2 behavior may significantly distort the results of membrane filtration processes, and therefore, the combination of classical and molecular methods used here is useful for an effective validation of the retention efficiency of ultrafiltration membranes.
Autoregulation of Lantibiotic Bovicin HJ50 Biosynthesis by the BovK-BovR Two-Component Signal Transduction System in
Streptococcus bovis
HJ50
Authors: Ni Jianqiang , Teng Kunling , Liu Gang , Qiao Caixia , Huan Liandong , Zhong Jin 
Published: November 2010

ABSTRACT

Streptococcus bovis
HJ50 produces a lacticin 481-like 33-amino-acid-residue lantibiotic, designated bovicin HJ50.
bovK-bovR
in the bovicin HJ50 biosynthetic gene cluster is predicted to be a two-component signal transduction system involved in sensing signals and regulating gene expression. Disruption of
bovK
or
bovR
resulted in the abrogation of bovicin HJ50 production, suggesting both genes play important roles in bovicin HJ50 biosynthesis. Addition of exogenous bovicin HJ50 peptide to cultures of a
bovM
mutant that lost the capability for bovicin HJ50 production and structural gene
bovA
transcription in
S. bovis
HJ50 induced dose-dependent transcription of the
bovA
gene, demonstrating that bovicin HJ50 production was normally autoregulated. The transcription of
bovA
was no longer induced by bovicin HJ50 in
bovK
and
bovR
disruption mutants, suggesting that BovK-BovR plays an essential role in the signal transduction regulating bovicin HJ50 biosynthesis. A phosphorylation assay indicated that BovK has the ability to autophosphorylate and subsequently transfer the phosphoryl group to the downstream BovR protein to carry on signal transduction. Electromobility shift assays (EMSA) and green fluorescent protein (GFP) reporter gene expression assays showed the specific binding of BovR to the
bovA
promoter, indicating that BovR regulates
bovA
expression by direct binding between them. Taken together, bovicin HJ50 biosynthesis is induced by bovicin HJ50 itself and regulated via the two-component signal transduction system BovK-BovR.
Effect of Environmental Factors and Influence of Rumen and Hindgut Biogeography on Bacterial Communities in Steers
Authors: Romero-Pérez Gustavo A. , Ominski Kim H. , McAllister Tim A. , Krause Denis O. 
Published: November 2010

ABSTRACT

Feces from cattle production are considered important sources of bacterial contamination of food and the environment. Little is known about the combined effects of arctic temperatures and fodder tannins on rumen and hindgut bacterial populations. Individual rumen liquor and rectal fecal samples from donor steers fed either alfalfa silage or sainfoin (
Onobrychis viciifolia
Scop.) silage and water
ad libitum
were collected weekly on the first three sampling days and fortnightly afterwards. The daily ambient temperatures were registered and averaged to weekly mean temperatures. Steers fed sainfoin silage had lower (
P
< 0.05) concentrations of branched-chain volatile fatty acids (VFA) than those fed alfalfa silage. All VFA concentrations were higher (
P
< 0.001) in rumen liquor samples than in fecal samples. The interaction of sample type and diet showed a significant effect (
P
< 0.05) on the proportions of the bacterial community that were from the phyla
Proteobacteria
and
Verrucomicrobia.
Ambient temperature had an indirect effect (
P
< 0.05) on the phylum
Firmicutes
, as it affected its proportional balance. The bacterial population diversity in samples appeared to decrease concurrently with the ambient temperature. The phylum
Firmicutes
explained the first principal component at 64.83 and 42.58% of the total variance in rumen liquor and fecal samples, respectively. The sample type had a larger effect on bacterial communities than diet and temperature. Certain bacterial populations seemed to be better adapted than others to environmentally adverse conditions, such as less access time to nutrients due to higher motility and rate of passage of digesta caused by extreme temperatures, or antimicrobials such as tannins, possibly due to an influence of their biogeographical location within the gut.
Microbial Community Fingerprinting by Differential Display-Denaturing Gradient Gel Electrophoresis
Authors: Portillo M. C. , Villahermosa D. , Corzo A. , Gonzalez J. M. 
Published: November 2010

ABSTRACT
Complex microbial communities exhibit a large diversity, hampering differentiation by DNA fingerprinting. Herein, differential display-denaturing gradient gel electrophoresis is proposed. By adding a nucleotide to the 3′ ends of PCR primers, 16 primer pairs and fingerprints were generated per community. Complexity reduction in each partial fingerprint facilitates sample comparison.
Influence of External Resistance on Electrogenesis, Methanogenesis, and Anode Prokaryotic Communities in Microbial Fuel Cells
Authors: Jung Sokhee , Regan John M. 
Published: November 2010

ABSTRACT

The external resistance (
R
ext
) of microbial fuel cells (MFCs) regulates both the anode availability as an electron acceptor and the electron flux through the circuit. We evaluated the effects of
R
ext
on MFCs using acetate or glucose. The average current densities (
I
) ranged from 40.5 mA/m
2
(9,800 Ω) to 284.5 mA/m
2
(150 Ω) for acetate-fed MFCs (acetate-fed reactors [ARs]), with a corresponding anode potential (
E
an
) range of −188 to −4 mV (versus a standard hydrogen electrode [SHE]). For glucose-fed MFCs (glucose-fed reactors [GRs]),
I
ranged from 40.0 mA/m
2
(9,800 Ω) to 273.0 mA/m
2
(150 Ω), with a corresponding
E
an
range of −189 to −7 mV. ARs produced higher Coulombic efficiencies and energy efficiencies than GRs over all tested
R
ext
levels because of electron and potential losses from glucose fermentation. Biogas production accounted for 14 to 18% of electron flux in GRs but only 0 to 6% of that in ARs. GRs produced similar levels of methane, regardless of the
R
ext
. However, total methane production in ARs increased as
R
ext
increased, suggesting that
E
an
might influence the competition for substrates between exoelectrogens and methanogens in ARs. An increase of
R
ext
to 9,800 Ω significantly changed the anode bacterial communities for both ARs and GRs, while operating at 970 Ω and 150 Ω had little effect.
Deltaproteobacteria
and
Bacteroidetes
were the major groups found in anode communities in ARs and GRs.
Betaproteobacteria
and
Gammaproteobacteria
were found only in ARs.
Bacilli
were abundant only in GRs. The anode-methanogenic communities were dominated by
Methanosaetaceae
, with significantly lower numbers of
Methanomicrobiales
. These results show that
R
ext
affects not only the
E
an
and current generation but also the anode biofilm community and methanogenesis.
Different Contributions of HtrA Protease and Chaperone Activities to
Campylobacter jejuni
Stress Tolerance and Physiology
Authors: Bæk Kristoffer T. , Vegge Christina S. , Skórko-Glonek Joanna , Brøndsted Lone 
Published: November 2010

ABSTRACT

The microaerophilic bacterium
Campylobacter jejuni
is the most common cause of bacterial food-borne infections in the developed world. Tolerance to environmental stress relies on proteases and chaperones in the cell envelope, such as HtrA and SurA. HtrA displays both chaperone and protease activities, but little is known about how each of these activities contributes to stress tolerance in bacteria.
In vitro
experiments showed temperature-dependent protease and chaperone activities of
C. jejuni
HtrA. A
C. jejuni
mutant lacking only the protease activity of HtrA was used to show that the HtrA chaperone activity is sufficient for growth at high temperature or under oxidative stress, whereas the HtrA protease activity is essential only under conditions close to the growth limit for
C. jejuni
. However, the protease activity was required to prevent induction of the cytoplasmic heat shock response even under optimal growth conditions. Interestingly, the requirement of HtrA at high temperatures was found to depend on the oxygen level, and our data suggest that HtrA may protect oxidatively damaged proteins. Finally, protease activity stimulates HtrA production and oligomer formation, suggesting that a regulatory role depends on the protease activity of HtrA. Studying a microaerophilic organism encoding only two known periplasmic chaperones (HtrA and SurA) revealed an efficient HtrA chaperone activity and proposed multiple roles of the protease activity, increasing our understanding of HtrA in bacterial physiology.
Environmental Patterns Are Imposed on the Population Structure of
Escherichia coli
after Fecal Deposition
Authors: Bergholz Peter W. , Noar Jesse D. , Buckley Daniel H. 
Published: November 2010

ABSTRACT

The intestinal microbe
Escherichia coli
is subject to fecal deposition in secondary habitats, where it persists transiently, allowing for the opportunity to colonize new hosts. Selection in the secondary habitat can be postulated, but its impact on the genomic diversity of
E. coli
is unknown. Environmental selective pressure on extrahost
E. coli
can be revealed by landscape genetic analysis, which examines the influences of dispersal processes, landscape features, and the environment on the spatiotemporal distribution of genes in natural populations. We conducted multilocus sequence analysis of 353
E. coli
isolates from soil and fecal samples obtained in a recreational meadow to examine the ecological processes controlling their distributions. Soil isolates, as a group, were not genetically distinct from fecal isolates, with only 0.8% of genetic variation and no fixed mutations attributed to the isolate source. Analysis of the landscape genetic structure of
E. coli
populations showed a patchy spatial structure consistent with patterns of fecal deposition. Controlling for the spatial pattern made it possible to detect environmental gradients of pH, moisture, and organic matter corresponding to the genetic structure of
E. coli
in soil. Ecological distinctions among
E. coli
subpopulations (i.e.,
E. coli
reference collection [ECOR] groups) contributed to variation in subpopulation distributions. Therefore, while fecal deposition is the major predictor of
E. coli
distributions on the field scale, selection imposed by the soil environment has a significant impact on
E. coli
population structure and potentially amplifies the occasional introduction of stress-tolerant strains to new host individuals by transmission through water or food.
Army Ants Harbor a Host-Specific Clade of
Entomoplasmatales
Bacteria
Authors: Funaro Colin F. , Kronauer Daniel J. C. , Moreau Corrie S. , Goldman-Huertas Benjamin , Pierce Naomi E. , Russell Jacob A. 
Published: November 2010

ABSTRACT

In this article, we describe the distributions of
Entomoplasmatales
bacteria across the ants, identifying a novel lineage of gut bacteria that is unique to the army ants. While our findings indicate that the
Entomoplasmatales
are not essential for growth or development, molecular analyses suggest that this relationship is host specific and potentially ancient. The documented trends add to a growing body of literature that hints at a diversity of undiscovered associations between ants and bacterial symbionts.
Extracellular Aldonolactonase from
Myceliophthora thermophila
Authors: Beeson William T. , Iavarone Anthony T. , Hausmann Corinne D. , Cate Jamie H. D. , Marletta Michael A. 
Published: November 2010

ABSTRACT

Fungi secrete many different enzymes to deconstruct lignocellulosic biomass, including several families of hydrolases, oxidative enzymes, and many uncharacterized proteins. Here we describe the isolation, characterization, and primary sequence analysis of an extracellular aldonolactonase from the thermophilic fungus
Myceliophthora thermophila
(synonym
Sporotrichum thermophile
). The lactonase is a 48-kDa glycoprotein with a broad pH optimum. The enzyme catalyzes the hydrolysis of glucono-δ-lactone and cellobiono-δ-lactone with an apparent second-order rate constant,
k
cat
/

K
m

, of ∼1 × 10
6
M
−1
s
−1
at pH 5.0 and 25°C but is unable to hydrolyze xylono-γ-lactone or arabino-γ-lactone. Sequence analyses of the lactonase show that it has distant homology to
cis
-carboxy-muconate lactonizing enzymes (CMLE) as well as 6-phosphogluconolactonases present in some bacteria. The
M. thermophila
genome contains two predicted extracellular lactonase genes, and expression of both genes is induced by the presence of pure cellulose. Homologues of the
M. thermophila
lactonase, which are also predicted to be extracellular, are present in nearly all known cellulolytic ascomycetes.
Transformation of, and Heterologous Protein Expression in,
Lactobacillus agilis
and
Lactobacillus vaginalis
Isolates from the Chicken Gastrointestinal Tract
Authors: Stephenson David P. , Moore Robert J. , Allison Gwen E. 
Published: November 2010

ABSTRACT

Lactobacilli are naturally found in the gastrointestinal tract of chickens, and there is interest in utilizing autochthonous strains for the delivery of therapeutic proteins. Previously we identified three chicken-derived
Lactobacillus
strains,
Lactobacillus agilis
La3,
Lactobacillus vaginalis
Lv5, and
Lactobacillus crispatus
Lc9, which persist in the gastrointestinal tract of chickens fed either a commercial or high-protein diet. In the current study, we investigated the ability to electrotransform these strains, determined plasmid vector stability, and compared reporter gene expression directed by several different promoters. The La3 and Lv5 strains were reproducibly transformed with efficiencies of 10
8
and 10
6
transformants per microgram of plasmid DNA, respectively. The third strain tested,
L. crispatus
Lc9, was recalcitrant to all transformation protocols examined. The plasmid vectors pTRK563 and pTRKH2 were maintained over 100 generations in La3 and Lv5, respectively. The ability of La3 and Lv5 to express the heterologous reporter gene
gfp
was analyzed using heterologous and homologous promoters. Transformants of both La3 and Lv5 containing the La3
ldhL
promoter were the most fluorescent. To our knowledge, this is the first report of successful transformation and heterologous protein expression in
L. agilis
and
L. vaginalis
. The ability of these strains to express heterologous proteins
in vitro
indicates their potential utility as
in vivo
delivery vectors for therapeutic peptides to the chicken gastrointestinal tract.
Recombination Shapes the Structure of an Environmental
Vibrio cholerae
Population
Authors: Keymer Daniel P. , Boehm Alexandria B. 
Published: November 2010

ABSTRACT

Vibrio cholerae
consists of pathogenic strains that cause sporadic gastrointestinal illness or epidemic cholera disease and nonpathogenic strains that grow and persist in coastal aquatic ecosystems. Previous studies of disease-causing strains have shown
V. cholerae
to be a primarily clonal bacterial species, but isolates analyzed have been strongly biased toward pathogenic genotypes, while representing only a small sample of the vast diversity in environmental strains. In this study, we characterized homologous recombination and structure among 152 environmental
V. cholerae
isolates and 13 other putative
Vibrio
isolates from coastal waters and sediments in central California, as well as four clinical
V. cholerae
isolates, using multilocus sequence analysis of seven housekeeping genes. Recombinant regions were identified by at least three detection methods in 72% of our
V. cholerae
isolates. Despite frequent recombination, significant linkage disequilibrium was still detected among the
V. cholerae
sequence types. Incongruent but nonrandom associations were observed for maximum likelihood topologies from the individual loci. Overall, our estimated recombination rate in
V. cholerae
of 6.5 times the mutation rate is similar to those of other sexual bacteria and appears frequently enough to restrict selection from purging much of the neutral intraspecies diversity. These data suggest that frequent recombination among
V. cholerae
may hinder the identification of ecotypes in this bacterioplankton population.
Type 2C Protein Phosphatases in Fungi
Authors: Ariño Joaquín , Casamayor Antonio , González Asier 
Published: November 2010

ABSTRACTType 2C Ser/Thr phosphatases are a remarkable class of protein phosphatases, which are conserved in eukaryotes and involved in a large variety of functional processes. Unlike in other Ser/Thr phosphatases, the catalytic polypeptide is not usually associated with regulatory subunits, and functional specificity is achieved by encoding multiple isoforms. For fungi, most information comes from the study of type 2C protein phosphatase (PP2C) enzymes inSaccharomyces cerevisiae, where seven PP2C-encoding genes (PTC1to-7) with diverse functions can be found. More recently, data on severalCandida albicansPP2C proteins became available, suggesting that some of them can be involved in virulence. In this work we review the available literature on fungal PP2Cs and explore sequence databases to provide a comprehensive overview of these enzymes in fungi.
Genetic and Mass Spectrometry Analyses of the Unusual Type IV-Like Pili of the ArchaeonMethanococcus maripaludis
Authors: Ng Sandy Y. M. , Wu John , Nair Divya B. , Logan Susan M. , Robotham Anna , Tessier Luc , Kelly John F. , Uchida Kaoru , Aizawa Shin-Ichi , Jarrell Ken F. 
Published: November 2010

ABSTRACTThe structure of pili from the archaeonMethanococcus maripaludisis unlike that of any bacterial pili. However, genetic analysis of the genes involved in the formation of these pili has been lacking until this study. Pili were isolated from a nonflagellated (ΔflaK) mutant and shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to consist primarily of subunits with an apparent molecular mass of 17 kDa. In-frame deletions were created in three genes,MMP0233,MMP0236, andMMP0237, which encode proteins with bacterial type IV pilin-like signal peptides previously identified byin silicomethodology as likely candidates for pilus structural proteins. Deletion ofMMP0236orMMP0237resulted in mutant cells completely devoid of pili on the cell surface, while deletion of the third pilin-like gene,MMP0233, resulted in cells greatly reduced in the number of pili on the surface. Complementation with the deleted gene in each case returned the cells to a piliated state. Surprisingly, mass spectrometry analysis of purified pili identified the major structural pilin as another type IV pilin-like protein, MMP1685, whose gene is located outside the first pilus locus. This protein was found to be glycosylated with an N-linked branched pentasaccharide glycan. Deletion and complementation analysis confirmed that MMP1685 is required for piliation.
Opposing Contributions of Polynucleotide Phosphorylase and the Membrane Protein NlpI to Biofilm Formation by
Salmonella enterica
Serovar Typhimurium
Authors: Rouf Syed Fazle , Ahmad Irfan , Anwar Naeem , Vodnala Suman Kumar , Kader Abdul , Römling Ute , Rhen Mikael 
Published: November 2010

ABSTRACT

CsgD and cyclic-3′,5′-di-guanylate are key regulators of biofilm formation in
Salmonella enterica
serovar Typhimurium. Our results show that polynucleotide phosphorylase and NlpI oppositely altered expression of CsgD. Polynucleotide phosphorylase and NlpI also had opposite effects on the expression of
yjcC
, which codes for a cyclic-3′,5′-di-guanylate phosphodiesterase affecting CsgD expression.