bluuebunny/crossref_metadata_2025_split huggingface dataset:
Posttranscriptional Regulation of Glutamine Synthetase in the Filamentous Cyanobacterium
Anabaena
sp. PCC 7120: Differential Expression between Vegetative Cells and Heterocysts
Authors: Galmozzi Carla V. , Saelices Lorena , Florencio Francisco J. , Muro-Pastor M. Isabel 
Published: July 2010

ABSTRACT

Genes homologous to those implicated in glutamine synthetase (GS) regulation by protein-protein interaction in the cyanobacterium
Synechocystis
sp. strain PCC 6803 are conserved in several cyanobacterial sequenced genomes. We investigated this GS regulatory mechanism in
Anabaena
sp. strain PCC 7120. In this strain the system operates with only one GS inactivation factor (inactivation factor 7A [IF7A]), encoded by open reading frame (ORF)
asl2329
(
gifA
). Following addition of ammonium, expression of
gifA
is derepressed, leading to the synthesis of IF7A, and consequently, GS is inactivated. Upon ammonium removal, the GS activity returns to the initial level and IF7A becomes undetectable. The global nitrogen control protein NtcA binds to the
gifA
promoter. Constitutive high expression levels of
gifA
were found in an
Anabaena ntcA
mutant (CSE2), indicating a repressor role for NtcA.
In vitro
studies demonstrate that
Anabaena
GS is not inactivated by
Synechocystis
IFs (IF7 and IF17), indicating the specificity of the system. We constructed an
Anabaena
strain expressing a second inactivating factor, containing the amino-terminal part of IF17 from
Synechocystis
fused to IF7A. GS inactivation in this strain is more effective than that in the wild type (WT) and resembles that observed in
Synechocystis
. Finally we found differential expression of the IF system between heterocysts and vegetative cells of
Anabaena
.
Aromatic Acid Metabolites of
Escherichia coli
K-12 Can Induce the
marRAB
Operon
Authors: Chubiz Lon M. , Rao Christopher V. 
Published: July 2010

ABSTRACT

MarR is a key regulator of the
marRAB
operon involved in antibiotic resistance and solvent stress tolerance in
Escherichia coli
. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate
marRAB
transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates
marRAB
transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.
Molecular Cloning, Expression, and Characterization of a Ca
2+
-Dependent, Membrane-Associated Nuclease of
Mycoplasma genitalium
Authors: Li Linbo , Krishnan Manickam , Baseman Joel B. , Kannan T. R. 
Published: July 2010

ABSTRACT

In this study, we identified and characterized the enzymatic properties of MG_186, a calcium-dependent
Mycoplasma genitalium
nuclease. MG_186 displays the hallmarks of nucleases, as indicated by its amino acid sequence similarity to other nucleases. We cloned, UGA corrected, expressed, purified, and demonstrated that recombinant MG_186 (rMG_186) exhibits nuclease activity similar to that of typical sugar-nonspecific endonucleases and exonucleases. Biochemical characterization indicated that Ca
2+
alone enhances its activity, which was inhibited by divalent cations, such as Zn
2+
and Mn
2+
. Chelating agents EGTA and EDTA also inhibited nuclease activity. Mycoplasma membrane fractionation and Triton X-114 phase separation showed that MG_186 was a membrane-associated lipoprotein, and electron microscopy revealed its surface membrane location. Incubation of purified human endometrial cell nuclei with rMG_186 resulted in DNA degradation and morphological changes typical of apoptosis. Further, immunofluorescence analysis of rMG_186-treated nuclei indicated that morphological changes were linked to the disintegration of lamin and the internalization of rMG_186. Since
M. genitalium
has the capacity to invade eukaryotic cells and localize to the perinuclear and nuclear region of parasitized target cells, MG_186 has the potential to provide
M. genitalium
, which possesses the smallest genome of any self-replicating cell, with the ability to degrade host nucleic acids both as a source of nucleotide precursors for growth and for pathogenic purposes.
Expressed Genome of
Methylobacillus flagellatus
as Defined through Comprehensive Proteomics and New Insights into Methylotrophy
Authors: Hendrickson Erik L. , Beck David A. C. , Wang Tiansong , Lidstrom Mary E. , Hackett Murray , Chistoserdova Ludmila 
Published: July 2010

ABSTRACT

In recent years, techniques have been developed and perfected for high-throughput identification of proteins and their accurate partial sequencing by shotgun nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS), making it feasible to assess global protein expression profiles in organisms with sequenced genomes. We implemented comprehensive proteomics to assess the expressed portion of the genome of
Methylobacillus flagellatus
during methylotrophic growth. We detected a total of 1,671 proteins (64% of the inferred proteome), including all the predicted essential proteins. Nonrandom patterns observed with the nondetectable proteins appeared to correspond to silent genomic islands, as inferred through functional profiling and genome localization. The protein contents in methylamine- and methanol-grown cells showed a significant overlap, confirming the commonality of methylotrophic metabolism downstream of the primary oxidation reactions. The new insights into methylotrophy include detection of proteins for the
N
-methylglutamate methylamine oxidation pathway that appears to be auxiliary and detection of two alternative enzymes for both the 6-phosphogluconate dehydrogenase reaction (GndA and GndB) and the formate dehydrogenase reaction (FDH1 and FDH4). Mutant analysis revealed that GndA and FDH4 are crucial for the organism's fitness, while GndB and FDH1 are auxiliary.
The ABC Transporter HrtAB Confers Resistance to Hemin Toxicity and Is Regulated in a Hemin-Dependent Manner by the ChrAS Two-Component System inCorynebacterium diphtheriae
Authors: Bibb Lori A. , Schmitt Michael P. 
Published: July 2010

ABSTRACTCorynebacterium diphtheriae, the causative agent of the severe respiratory disease diphtheria, utilizes hemin and hemoglobin as iron sources for growth in iron-depleted environments. Because of the toxicity of high levels of hemin and iron, these compounds are often tightly regulated in bacterial systems. In this report, we identify and characterize theC. diphtheriae hrtABgenes, which encode a putative ABC type transporter involved in conferring resistance to the toxic effects of hemin. Deletion of thehrtABgenes inC. diphtheriaeproduced increased sensitivity to hemin, which was complemented by a plasmid harboring the clonedhrtABlocus. The HrtAB system was not involved in the uptake and use of hemin as an iron source. ThehrtABgenes are located on theC. diphtheriaegenome upstream from thechrSAoperon, which encodes a previously characterized two-component signal transduction system that regulates gene expression in a heme-dependent manner. ThehrtBpromoter is activated by the ChrAS system in the presence of hemin or hemoglobin, and mutations in thechrSAgenes abolish heme-activated expression from thehrtBpromoter. It was also observed that transcription from thehrtBpromoter is reduced in adtxRdeletion mutant, suggesting that DtxR is required for optimal expression ofhrtAB. Previous studies proposed that the ChrS sensor kinase may be responsive to an environmental signal, such as hemin. We show that specific point mutations in the ChrS N-terminal transmembrane domain result in a reduced ability to activate thehrtBpromoter in the presence of a heme source, suggesting that this putative sensor region is essential for the detection of a signal produced in response to hemin exposure. This study shows that the HrtAB system is required for protection from hemin toxicity and that expression of thehrtABgenes is regulated by the ChrAS two-component system. This study demonstrates a direct correlation between the detection of heme or a heme-associated signal by the N-terminal sensor domain of ChrS and the transcriptional activation of thehrtABgenes.
Massive Gene Duplication Event among Clinical Isolates of the
Mycobacterium tuberculosis
W/Beijing Family
Authors: Domenech Pilar , Kolly Gaëlle S. , Leon-Solis Lizbel , Fallow Ashley , Reed Michael B. 
Published: July 2010

ABSTRACT

As part of our effort to uncover the molecular basis for the phenotypic variation among clinical
Mycobacterium tuberculosis
isolates, we have previously reported that isolates belonging to the W/Beijing lineage constitutively overexpress the DosR-regulated transcriptional program. While generating
dosR
knockouts in two independent W/Beijing sublineages, we were surprised to discover that they possess two copies of
dosR
. This
dosR
amplification is part of a massive genomic duplication spanning 350 kb and encompassing >300 genes. In total, this equates to 8% of the genome being present as two copies. The presence of I
S6110
elements at both ends of the region of duplication, and in the novel junction region, suggests that it arose through unequal homologous recombination of sister chromatids at the IS
6110
sequences. Analysis of isolates representing the major
M. tuberculosis
lineages has revealed that the 350-kb duplication is restricted to the most recently evolved sublineages of the W/Beijing family. Within these isolates, the duplication is partly responsible for the constitutive
dosR
overexpression phenotype. Although the nature of the selection event giving rise to the duplication remains unresolved, its evolution is almost certainly the result of specific selective pressure(s) encountered inside the host. A preliminary
in vitro
screen has failed to reveal a role of the duplication in conferring resistance to common antitubercular drugs, a trait frequently associated with W/Beijing isolates. Nevertheless, this first description of a genetic remodeling event of this nature for
M. tuberculosis
further highlights the potential for the evolution of diversity in this important global pathogen.
In-Depth Profiling of the LiaR Response ofBacillus subtilis
Authors: Wolf Diana , Kalamorz Falk , Wecke Tina , Juszczak Anna , Mäder Ulrike , Homuth Georg , Jordan Sina , Kirstein Janine , Hoppert Michael , Voigt Birgit , Hecker Michael , Mascher Thorsten 
Published: July 2010

ABSTRACTThe Lia system, a cell envelope stress response module ofBacillus subtilis, is comprised of the LiaRS two-component system and a membrane-anchored inhibitor protein, LiaF. It is highly conserved in theFirmicutesbacteria, and all orthologs investigated so far are activated by cell wall antibiotics. In response to envelope stress, the systems inFirmicutescocci induce the expression of a number of genes that are involved in conferring resistance against its inducers. In contrast, a complete picture of the LiaR regulon ofB. subtilisis still missing and no phenotypes could be associated with mutants lacking LiaRS. Here, we performed genome-wide transcriptomic, proteomic, and in-depth phenotypic profiling of constitutive “Lia ON” and “Lia OFF” mutants to obtain a comprehensive picture of the Lia response ofBacillus subtilis. In addition to the known targetsliaIHandyhcYZ-yhdA, we identifiedydhEas a novel gene affected by LiaR-dependent regulation. The results of detailed follow-up gene expression studies, together with proteomic analysis, demonstrate that theliaIHoperon represents the only relevant LiaR target locusin vivo. It encodes a small membrane protein (LiaI) and a phage shock protein homolog (LiaH). LiaH forms large oligomeric rings reminiscent of those described forEscherichia coliPspA orArabidopsis thalianaVipp1. The results of comprehensive phenotype studies demonstrated that the gene products of theliaIHoperon are involved in protecting the cell against oxidative stress and some cell wall antibiotics. Our data suggest that the LiaFSR system ofB. subtilisand, presumably, otherFirmicutesbacilli coordinates a phage shock protein-like response.
Separate DNA Pol II- and Pol IV-Dependent Pathways of Stress-Induced Mutation during Double-Strand-Break Repair in
Escherichia coli
Are Controlled by RpoS
Authors: Frisch Ryan L. , Su Yang , Thornton P. C. , Gibson Janet L. , Rosenberg Susan M. , Hastings P. J. 
Published: July 2010

ABSTRACT

Previous work showed that about 85% of stress-induced mutations associated with DNA double-strand break repair in carbon-starved
Escherichia coli
result from error-prone DNA polymerase IV (Pol IV) (DinB) and that the mutagenesis is controlled by the RpoS stress response, which upregulates
dinB
. We report that the remaining mutagenesis requires high-fidelity Pol II, and that this component also requires RpoS. The results identify a second DNA polymerase contributing to stress-induced mutagenesis and show that RpoS promotes mutagenesis by more than the simple upregulation of
dinB
.
Complete Genome Sequence of
Lactobacillus fermentum
CECT 5716, a Probiotic Strain Isolated from Human Milk
Authors: Jiménez Esther , Langa Susana , Martín Virginia , Arroyo Rebeca , Martín Rocío , Fernández Leónides , Rodríguez Juan M. 
Published: July 2010

ABSTRACT

Lactobacillus fermentum
is a heterofermentative lactic acid bacterium and is frequently isolated from mucosal surfaces of healthy humans.
Lactobacillus fermentum
CECT 5716 is a well-characterized probiotic strain isolated from human milk and, at present, is used in commercial infant formulas. Here, we report the complete and annotated genome sequence of this strain.
Complete Genome Sequence of
Croceibacter atlanticus
HTCC2559
T
Authors: Oh Hyun-Myung , Kang Ilnam , Ferriera Steve , Giovannoni Stephen J. , Cho Jang-Cheon 
Published: July 2010

ABSTRACT

Here we announce the complete genome sequence of
Croceibacter atlanticus
HTCC2559
T
, which was isolated by high-throughput dilution-to-extinction culturing from the Bermuda Atlantic Time Series station in the Western Sargasso Sea. Strain HTCC2559
T
contained genes for carotenoid biosynthesis, flavonoid biosynthesis, and several macromolecule-degrading enzymes. The genome confirmed physiological observations of cultivated
Croceibacter atlanticus
strain HTCC2559
T
, which identified it as an obligate chemoheterotroph.
Periaortic Fat Deposition Is Associated With Peripheral Arterial Disease
Authors: Fox Caroline S. , Massaro Joseph M. , Schlett Christopher L. , Lehman Sam J. , Meigs James B. , O'Donnell Christopher J. , Hoffmann Udo , Murabito Joanne M. 
Published: July 2010

Background—
Central obesity is associated with peripheral arterial disease, suggesting that ectopic fat depots may be associated with localized diseases of the aorta and lower-extremity arteries. We hypothesized that persons with greater amounts of periaortic fat are more likely to have clinical PAD and a low ankle-brachial index.

Methods and Results—

We quantified periaortic fat surrounding the thoracic aorta using a novel volumetric quantitative approach in 1205 participants from the Framingham Heart Study Offspring cohort (mean age, 65.9 years; women, 54%); visceral abdominal fat also was measured. Clinical peripheral arterial disease was defined as a history of intermittent claudication, and ankle-brachial index was dichotomized as low (≤0.9) or lower-extremity revascularization versus normal (>0.9 to <1.4). Regression models were created to examine the association between periaortic fat and intermittent claudication or low ankle-brachial index (n=66). In multivariable logistic regression, per 1 SD increase in periaortic fat, the odds ratio for the combined end point was 1.52 (
P
=0.004); these results were strengthened with additional adjustment for body mass index (odds ratio, 1.69;
P
=0.002) or visceral abdominal fat (odds ratio, 1.67;
P
=0.009), whereas no association was observed for visceral abdominal fat (
P
=0.16). Similarly, per SD increase in body mass index or waist circumference, no association was observed after accounting for visceral abdominal fat (body mass index,
P
=0.35; waist circumference,
P
=0.49).

Conclusions—
Periaortic fat is associated with low ABI and intermittent claudication.
Familial prevalence of autoimmune disorders in multiple sclerosis in Northern Greece
Authors: Deretzi Georgia , Kountouras Jannis , Koutlas Evangelos , Zavos Christos , Polyzos Stergios , Rudolf Jobst , Grigoriadis Nikolaos , Gavalas Emmanuel , Boziki Marina , Tsiptsios Iakovos 
Published: July 2010

Objective: The objective of this study was to evaluate for up to 7 years the prevalence of autoimmune disorders among naïve (untreated) multiple sclerosis family members compared with a contemporary general control population in Northern Greece, in a prospective case-control study, and to examine the possible relationship between immunomodulatory treatment and the appearance of additional autoimmune disorders. Methods: The patients and controls enrolled comprised 1383 patients with definite MS and 4392 relatives in their families and a total of 452 controls families with 1652 members. Results: At baseline, 891 multiple sclerosis families with 3112 members (73 multiplex multiple sclerosis families with 292 members and 818 simplex families with 2820 members) and 355 control families with 1580 members were examined regarding whether they had any of 12 autoimmune diseases. The baseline affected multiplex plus simplex multiple sclerosis families, the family members and the coexistent additional autoimmune disorders were higher compared with controls. There was an increase in longitudinally affected multiple sclerosis families, multiple sclerosis family members and coexistent additional autoimmune disorders compared with respective findings at the baseline observation. Comparison analysis between two time point observations (after a mean 7.1 ± 2.2 years) for each autoimmune disorder in overall multiple sclerosis family members revealed increased rates for longitudinal autoimmune Hashimoto’s thyroiditis, Graves’ disease, insulin-dependent diabetes mellitus, psoriasis and vitiligo ( p = 0.02, p = 0.006, p = 0.0004, p = 0.05, and p = 0.05, respectively). Some 145 newly developed, longitudinally definite autoimmune cases were recognized in multiplex plus simplex multiple sclerosis families; 116 (80%) of these disorders were observed in patients with multiple sclerosis treated with immunomodulatory medications, and 68 of these 116 (58.6%) cases exhibited baseline positive autoreactive antibodies. Binary logistic regression analysis revealed that immunotherapy predisposes to autoimmunity (odds ratio 2.8, p < 0.001) independently of the presence of baseline autoantibodies and patients’ gender. Conclusions: There is a longitudinally increased frequency of additional autoimmune disorders among multiple sclerosis family members, probably related to immunomodulatory therapy.
Correlates of institutionalized senior veterans' quality of life in Taiwan
Authors: Chang Hsiao-Ting , Liu Li-Fan , Chen Chun-Ku , Hwang Shinn-Jang , Chen Liang-Kung , Lu Feng-Hwa 
Published: July 2010

Abstract

Background
Senior veterans living in government sponsored, long-term care (LTC) facilities, known as veterans' homes (VHs), are a special minority group in Taiwan. These seniors came from different provinces of mainland China during their teenage years at the end of civil wars in 1945. The situation of institutionalized senior veterans shares many characteristics with the concept of "total institution". Very little quality of life (QOL) research has involved senior veterans. This study aimed to explore the QOL and related factors of VH-dwelling senior veterans in Taiwan.

Methods
Chronic conditions and socio-demographic characteristics of 260 male VH residents were recorded. The Brief Form of the World Health Organization's Quality of Life Questionnaire (WHOQOL-BREF, Taiwanese version); Short-Form 36; Inventory of Socially Supportive Behavior questionnaire; Geriatric Depression Scale-short form; Barthel Index; and instrumental activities of daily living were used. Data analyses including descriptive and inferred statistics were performed using SPSS, version 17.

Results
WHOQOL-BREF showed acceptable reliability in this study. Compared to Taiwanese male norms, WHOQOL-BREF physical, psychological, and social relationship domain scores were around the 25th percentile, and the environment domain was about the 75th percentile. Our participants scored low in all concepts of SF-36. Although these residents rated the social support of their children, relatives, friends, social and medical staff as low, they gave high satisfaction ratings to their social supports. On multiple stepwise linear regression analysis, depressive symptoms, number of chronic conditions, retired military rank, and relatives' support correlated with QOL in both the physical and psychological domains. Friends' support and depressive symptoms correlated with the social relationships domain. Friends' support and instrumental activities of daily living correlated with the environment domain.

Conclusions
In general, institutionalized senior veterans' QOL was lower than Taiwanese male norms. Helping senior veterans to effectively improve their subjective mental health and social support, and controlling chronic disease appears to be critical to their QOL.
Metformin and placebo therapy both improve weight management and fasting insulin in obese insulin-resistant adolescents: a prospective, placebo-controlled, randomized study
Authors: Wiegand Susanna , l'Allemand Dagmar , Hübel Hanna , Krude Heiko , Bürmann Mareike , Martus Peter , Grüters Annette , Holl Reinhard W 
Published: July 2010

ObjectiveTo study whether metformin reduces obesity, homeostasis model assessment for insulin resistance index (HOMA-IR), and the metabolic syndrome (MtS) in obese European adolescents in addition to previous unsuccessful lifestyle intervention.Design and methodsAfter 6 months of multiprofessional lifestyle intervention, 70 out of 86 adolescents without improvement in body mass index (BMI) and HOMA-IR were randomized into either the placebo (n=34) or the metformin group (2×500 mg/day,n=36) in addition to ongoing lifestyle intervention for another 6 months.ResultsAge was 13.8 years, BMI was 33.1 kg/m2, 65% were female, and 89% were Caucasians. During lifestyle intervention alone, BMI and HOMA-IR deteriorated significantly. In the subsequent medication period, HOMA-IR and fasting insulin improved similarly in the placebo and metformin groups (HOMA-IR decreased 73 vs 54% respectively in metformin versus placebo;P=0.048), but BMI remained unchanged. The insulin sensitivity index, however, only improved in the metformin group. High fasting insulin is correlated with a subsequent BMI increase irrespective of the medication. MtS remained unchanged.ConclusionsObese European adolescents' insulin sensitivity improved without weight change during placebo or metformin intervention in addition to lifestyle intervention. Most differences did not reach statistical significance, probably due to improved compliance with lifestyle intervention as a placebo effect. In addition, the metformin dose may be too low.