bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Diversity of the Gene Cluster Encoding Longus, a Type IV Pilus of Enterotoxigenic
Escherichia coli
Authors: Gomez-Duarte Oscar G. , Chattopadhyay Sujay , Weissman Scott J. , Giron Jorge A. , Kaper James B. , Sokurenko Evgeni V. 
Published: October 2007

ABSTRACT

Enterotoxigenic
Escherichia coli
(ETEC) strains produce a type IV pilus named Longus. We identified a 16-gene cluster involved in the biosynthesis of Longus that has 57 to 95% identity at the protein level to CFA/III, another type IV pilus of ETEC. Alleles of the Longus structural subunit gene
lngA
demonstrate a diversity of 12 to 19% at the protein level with strong positive selection for point replacements and horizontal transfer.
Introduction of the Foreign Transposon Tn
4560
in
Streptomyces coelicolor
Leads to Genetic Instability near the Native Insertion Sequence IS
1649
Authors: Widenbrant Elizabeth M. , Kao Camilla M. 
Published: October 2007

ABSTRACT

We report an altered pattern of genetic instability for
Streptomyces coelicolor
when the bacterium harbored a foreign transposon, Tn
4560
. Deletions, amplifications, and circularizations of the linear 8.7-Mb chromosome occurred more frequently at sites adjacent to native insertion elements, notably IS
1649
. In contrast, deletions, amplifications, and circularizations of a wild-type strain happened at heterogeneous sites within the chromosome. In 50 strains examined, structural changes removed or duplicated hundreds of contiguous
S. coelicolor
genes, altering up to 33% of the chromosome.
S. coelicolor
shows a bias toward one type of genetic instability during this particular assault from the environment, the invasion of foreign DNA.
Genome Sequence of
Staphylococcus aureus
Strain Newman and Comparative Analysis of Staphylococcal Genomes: Polymorphism and Evolution of Two Major Pathogenicity Islands
Authors: Baba Tadashi , Bae Taeok , Schneewind Olaf , Takeuchi Fumihiko , Hiramatsu Keiichi 
Published: October 2007

ABSTRACT

Strains of
Staphylococcus aureus
, an important human pathogen, display up to 20% variability in their genome sequence, and most sequence information is available for human clinical isolates that have not been subjected to genetic analysis of virulence attributes.
S. aureus
strain Newman, which was also isolated from a human infection, displays robust virulence properties in animal models of disease and has already been extensively analyzed for its molecular traits of staphylococcal pathogenesis. We report here the complete genome sequence of
S. aureus
Newman, which carries four integrated prophages, as well as two large pathogenicity islands. In agreement with the view that
S. aureus
Newman prophages contribute important properties to pathogenesis, fewer virulence factors are found outside of the prophages than for the highly virulent strain MW2. The absence of drug resistance genes reflects the general antibiotic-susceptible phenotype of
S. aureus
Newman. Phylogenetic analyses reveal clonal relationships between the staphylococcal strains Newman, COL, NCTC8325, and USA300 and a greater evolutionary distance to strains MRSA252, MW2, MSSA476, N315, Mu50, JH1, JH9, and RF122. However, polymorphism analysis of two large pathogenicity islands distributed among these strains shows that the two islands were acquired independently from the evolutionary pathway of the chromosomal backbones of staphylococcal genomes. Prophages and pathogenicity islands play central roles in
S. aureus
virulence and evolution.
Streptomyces coelicolor
Undergoes Spontaneous Chromosomal End Replacement
Authors: Widenbrant Elizabeth M. , Tsai Hsiu-Hui , Chen Carton W. , Kao Camilla M. 
Published: October 2007

ABSTRACT

We report a previously unobserved form of genetic instability for
Streptomyces coelicolor
, the replacement of one chromosome end by the other end. These genetic changes occurred spontaneously in both a wild-type strain and strains harboring a foreign transposon. Deleted and duplicated DNA comprises up to 33% of the genome.
A Novel Peroxiredoxin Activity Is Located within the C-Terminal End of
Rhodospirillum rubrum
Adenylyltransferase
Authors: Jonsson Anders , Teixeira Pedro Filipe , Nordlund Stefan 
Published: October 2007

ABSTRACT

Adenylyltransferase (GlnE) catalyzes the reversible adenylylation of glutamine synthetase. In this report we present, for the first time, evidence for a peroxiredoxin activity of
Rhodospirillum rubrum
GlnE, through the carboxyl-terminal AhpC/thiol-specific antioxidant (TSA) domain. The combination of GlnE and AhpC/TSA domains within the same polypeptide constitutes a unique domain architecture that has not previously been identified among proteobacteria.
New Target Genes Controlled by the
Bradyrhizobium japonicum
Two-Component Regulatory System RegSR
Authors: Lindemann Andrea , Moser Annina , Pessi Gabriella , Hauser Felix , Friberg Markus , Hennecke Hauke , Fischer Hans-Martin 
Published: October 2007

ABSTRACT

RegSR-like proteins, members of the family of two-component regulatory systems, are present in a large number of proteobacteria in which they globally control gene expression mostly in a redox-responsive manner. The controlled target genes feature an enormous functional diversity. In
Bradyrhizobium japonicum
, the facultative root nodule symbiont of soybean, RegSR activate the transcription of the nitrogen fixation regulatory gene
nifA
, thus forming a RegSR-NifA cascade which is part of a complex regulatory network for gene regulation in response to changing oxygen concentrations. Whole-genome transcription profiling was performed here in order to assess the full regulatory scope of RegSR. The comparative analysis of wild-type and Δ
regR
cells grown under oxic and microoxic conditions revealed that expression of almost 250 genes is dependent on RegR, a result that underscores the important contribution of RegR to oxygen- or redox-regulated gene expression in
B. japonicum
. Furthermore, transcription profiling of Δ
regR
bacteroids compared with wild-type bacteroids revealed expression changes for about 1,200 genes in young and mature bacteroids. Incidentally, many of these were found to be induced in symbiosis when wild-type bacteroids were compared with free-living, culture-grown wild-type cells, and they appeared to encode diverse functions possibly related to symbiosis and nitrogen fixation. We demonstrated direct RegR-mediated control at promoter regions of several selected target genes by means of DNA binding experiments and in vitro transcription assays, which revealed six novel direct RegR target promoters.
Cysteine Metabolism-Related Genes and Bacterial Resistance to Potassium Tellurite
Authors: Fuentes Derie E. , Fuentes Eugenia L. , Castro Miguel E. , Pérez José M. , Araya Manuel A. , Chasteen Thomas G. , Pichuantes Sergio E. , Vásquez Claudio C. 
Published: October 2007

ABSTRACT

Tellurite exerts a deleterious effect on a number of small molecules containing sulfur moieties that have a recognized role in cellular oxidative stress. Because cysteine is involved in the biosynthesis of glutathione and other sulfur-containing compounds, we investigated the expression of
Geobacillus stearothermophilus
V cysteine-related genes
cobA, cysK
, and
iscS
and
Escherichia coli
cysteine regulon genes under conditions that included the addition of K
2
TeO
3
to the culture medium. Results showed that cell tolerance to tellurite correlates with the expression level of the cysteine metabolic genes and that these genes are up-regulated when tellurite is present in the growth medium.
Cooperative Transport between NukFEG and NukH in Immunity against the Lantibiotic Nukacin ISK-1 Produced by
Staphylococcus warneri
ISK-1
Authors: Okuda Ken-ichi , Aso Yuji , Nakayama Jiro , Sonomoto Kenji 
Published: October 2007

ABSTRACT

Nukacin ISK-1 is a lantibiotic produced by
Staphylococcus warneri
ISK-1. Previous studies have reported that the self-protection system of the nukacin ISK-1 producer involves the cooperative function of the ABC transporter NukFEG and the lantibiotic-binding immunity protein NukH. In this study, the cooperative mechanism between NukFEG and NukH was characterized by using fluorescein-4-isothiocyanate (FITC)-labeled nukacin ISK-1 (FITC-nuk) to clarify the localization of nukacin ISK-1 in the immunity process.
Lactococcus lactis
recombinants expressing
nukFEGH
,
nukFEG
, or
nukH
showed immunity against FITC-nuk, suggesting that FITC-nuk was recognized by the self-protection system against nukacin ISK-1. Analysis of the interaction between FITC-nuk and energy-deprived cells of the
L. lactis
recombinants showed that FITC-nuk specifically bound to cells expressing
nukH
. The interaction between FITC-nuk and
nukH
-expressing cells was inhibited by the addition of unlabeled nukacin ISK-1 and its derivatives with deletions of the N-terminal tail region, but not by the addition of a synthesized N-terminal tail region. This suggests that the NukH protein recognizes the C-terminal ring region of nukacin ISK-1. The addition of glucose to
nukFEGH
-expressing cells treated with FITC-nuk resulted in a time-dependent decrease in fluorescence intensity, indicating that FITC-nuk was transported from the cell membrane by the NukFEG protein. These results revealed that after being captured by NukH in an energy-independent manner, nukacin ISK-1 was transported to the extracellular space by NukFEG in an energy-dependent manner.
Streptomyces coelicolorGenesftsLanddivICPlay a Role in Cell Division but Are Dispensable for Colony Formation
Authors: Bennett Jennifer A. , Aimino Rachel M. , McCormick Joseph R. 
Published: October 2007

ABSTRACTWe have characterized homologues of the bacterial cell division genesftsLanddivICin the gram-positive mycelial bacteriumStreptomyces coelicolorA3(2). We show by deletion-insertion mutations thatftsLanddivICare dispensable for growth and viability inS. coelicolor. When mutant strains were grown on a conventional rich medium (R2YE, containing high sucrose), inactivation of eitherftsLordivICresulted in the formation of aerial hyphae with partially constricted division sites but no clear separation of prespore compartments. Surprisingly, this phenotype was largely suppressed when strains were grown on minimal medium or sucrose-free R2YE, where division sites in many aerial hyphae had finished constricting and chains of spores were evident. Thus, osmolarity appears to affect the severity of the division defect. Furthermore, double mutant strains deleted for bothftsLanddivICare viable and have medium-dependent phenotypes similar to that of the single mutant strains, suggesting that functions performed by FtsL and DivIC are not absolutely required for septation during growth and sporulation. Alternatively, another division protein may partially compensate for the loss of both FtsL and DivIC on minimal medium or sucrose-free R2YE. Finally, based on transmission electron microscopy observations, we propose that FtsL and DivIC are involved in coordinating symmetrical annular ingrowth of the invaginating septum.
TheSalmonellaSPI1 Type Three Secretion System Responds to Periplasmic Disulfide Bond Status via the Flagellar Apparatus and the RcsCDB System
Authors: Lin Dongxia , Rao Christopher V. , Slauch James M. 
Published: October 2007

ABSTRACTUpon contact with intestinal epithelial cells,Salmonella entericaserovar Typhimurium injects a set of effector proteins into the host cell cytoplasm via theSalmonellapathogenicity island 1 (SPI1) type III secretion system (T3SS) to induce inflammatory diarrhea and bacterial uptake. The master SPI1 regulatory genehilAis controlled directly by three AraC-like regulators: HilD, HilC, and RtsA. Previous work suggested a role for DsbA, a periplasmic disulfide bond oxidase, in SPI1 T3SS function. RtsA directly activatesdsbA, and deletion ofdsbAleads to loss of SPI1-dependent secretion. We have studied thedsbAphenotypes by monitoring expression of SPI1 regulatory, structural, and effector genes. Here we present evidence that loss of DsbA independently affects SPI1 regulation and SPI1 function. ThedsbA-mediated feedback inhibition of SPI1 transcription is not due to defects in the SPI1 T3SS apparatus. Rather, the transcriptional response is dependent on both the flagellar protein FliZ and the RcsCDB system, which also affectsfliZtranscription. Thus, the status of disulfide bonds in the periplasm affects expression of the SPI1 system indirectly via the flagellar apparatus. RcsCDB can also affect SPI1 independently of FliZ. All regulation is through HilD, consistent with our current model for SPI1 regulation.
Identification of Two Gene Clusters and a Transcriptional Regulator Required for
Pseudomonas aeruginosa
Glycine Betaine Catabolism
Authors: Wargo Matthew J. , Szwergold Benjamin S. , Hogan Deborah A. 
Published: October 2007

ABSTRACT

Glycine betaine (GB), which occurs freely in the environment and is an intermediate in the catabolism of choline and carnitine, can serve as a sole source of carbon or nitrogen in
Pseudomonas aeruginosa
. Twelve mutants defective in growth on GB as the sole carbon source were identified through a genetic screen of a nonredundant PA14 transposon mutant library. Further growth experiments showed that strains with mutations in two genes,
gbcA
(PA5410) and
gbcB
(PA5411), were capable of growth on dimethylglycine (DMG), a catabolic product of GB, but not on GB itself. Subsequent nuclear magnetic resonance (NMR) experiments with 1,2-
13
C-labeled choline indicated that these genes are necessary for conversion of GB to DMG. Similar experiments showed that strains with mutations in the
dgcAB
(PA5398-PA5399) genes, which exhibit homology to genes that encode other enzymes with demethylase activity, are required for the conversion of DMG to sarcosine. Mutant analyses and
13
C NMR studies also confirmed that the
soxBDAG
genes, predicted to encode a sarcosine oxidase, are required for sarcosine catabolism. Our screen also identified a predicted AraC family transcriptional regulator, encoded by
gbdR
(PA5380), that is required for growth on GB and DMG and for the induction of
gbcA
,
gbcB
, and
dgcAB
in response to GB or DMG. Mutants defective in the previously described
gbt
gene (PA3082) grew on GB with kinetics similar to those of the wild type in both the PAO1 and PA14 strain backgrounds. These studies provided important insight into both the mechanism and the regulation of the catabolism of GB in
P. aeruginosa
.
Transmembrane Helix 12 of the
Staphylococcus aureus
Multidrug Transporter QacA Lines the Bivalent Cationic Drug Binding Pocket
Authors: Hassan Karl A. , Skurray Ronald A. , Brown Melissa H. 
Published: October 2007

ABSTRACT
An acidic residue in transmembrane segment (TMS) 10 is important for recognition of bivalent cationic substrates by the QacA multidrug transporter. Remarkably, an acidic residue in TMS 12 compensated for the absence of such a residue in TMS 10, suggesting that TMS 12 is a component of the bivalent cation-binding region.
Incidence of respiratory sensitisation and allergy to enzymes among employees in an enzyme producing plant and the relation to exposure and host factors
Authors: Larsen A I , Johnsen C R , Frickmann J , Mikkelsen S 
Published: October 2007

Objectives:Belonging to the group of high molecular weight respiratory sensitisers, microbial enzymes have been reported as a well known cause of occupational allergy, typically manifesting itself as rhinitis and/or asthma. High exposure to such high molecular weight sensitisers, and possibly also peak exposures, implies a higher risk than low exposure, but the exact relation between exposure, sensitisation and clinical allergy remains to be clarified. The authors sought to estimate the risk of respiratory enzyme allergy in an enzyme producing plant and to assess the relation between exposure indices and allergy.Methods:Retrospective follow-up study based upon data gathered from health surveillance since 1970. 1207 employees from production and laboratories were included. The level of enzyme exposure in the relevant departments was estimated retrospectively into five exposure levels based on 10-fold increments/decrements of the threshold limit value and other exposure information. The risk was estimated in an exponential regression survival model fitted with constant intensity for subperiods of time using maximum likelihood estimation.Results:During the first three years of a persons employment, the enzyme sensitisation and allergy incidence rates were 0.13 and 0.03 per person-year at risk, respectively. In the fitted models, exposure class did not correlate with the outcome variables. The risk of sensitisation decreased along the three decades, whereas the risk of allergy remained unchanged. The risk of sensitisation and allergy was doubled among smokers. Pre-employment atopy was only associated with sensitisation risk.Conclusion:Sensitisation to enzymes decreased during the study period, possibly reflecting improvements in the working environment. A similar decrease could not be demonstrated for allergy to enzymes. Neither of the two outcomes correlated with exposure estimates, possibly because of the low precision of the estimates.
Exposures and reported symptoms associated with occupational deployment to the Buncefield fuel depot fire, England 2005
Authors: Morgan O , Verlander N Q , Kennedy F , Moore M , Birch S , Kearney J , Lewthwaite P , Lewis R , O’Brian S , Osman J , Reacher M 
Published: October 2007

Objectives:An explosion at the Buncefield fuel depot outside London occurred on 11 December 2005. We conducted a retrospective cohort study of airborne exposures and health status for workers deployed.Methods:Deployed individuals were identified through their occupational health departments. We sent a self-completion questionnaire asking about health symptoms during the burn and post-burn phases. The prevalence of health symptoms in workers was compared to symptoms in local residents not under the smoke plume.Results:Of 1949 eligible individuals, 815 returned questionnaires (response rate 44). Respiratory protection was used by 39. Symptoms were reported by 41 of individuals during the burn phase compared with 26 in the post-burn phase. In a final multivariable model, reporting of any symptoms was associated with deployment inside the inner fire cordon during the burn phase (OR 2.07, 95 CI 1.24 to 3.47) and wearing a face mask (OR 2.33, 95 CI 1.67 to 3.26). Compared with the general public, eye irritation (prevalence ratio (PR) 2.1, 95 CI 1.5 to 3.0), coughing (PR 1.3, 95 CI 1.0 to 1.8) and headaches (PR 1.7, 95 CI 1.2 to 2.5) were more common in workers deployed during the burn phase but not the post-burn phase.Conclusions:Increased reporting of symptoms close to the fire during the burn phase was consistent with increased exposure to products of combustion, although no major acute illness was reported. That only a minority of individuals used face masks, which were not protective for symptoms, raises questions about the availability of adequate respiratory protection for such incidents.
Arterial structure and function and environmental exposure to cadmium
Authors: Schutte R , Nawrot T , Richart T , Thijs L , Roels H A , Van Bortel L M , Struijker-Boudier H , Staessen J A 
Published: October 2007

Objectives:Few studies have addressed the effect of cadmium toxicity on arterial properties.Methods:We investigated the possible association of 24 h urinary cadmium excretion (an index of lifetime exposure) with measures of arterial function in a randomly selected population sample (n  557) from two rural areas with low and high environmental exposure to cadmium.Results:24 h urinary cadmium excretion was significantly higher in the high compared with the low exposure group (p<0.001). Even though systolic (p  0.42), diastolic (p  0.14) and mean arterial pressure (p  0.68) did not differ between the high and low exposure groups, aortic pulse wave velocity (p  0.008), brachial pulse pressure (p  0.026) and femoral pulse pressure (p  0.008) were significantly lower in the high exposure group. Additionally, femoral distensibility (p<0.001) and compliance (p  0.001) were significantly higher with high exposure. Across quartiles of 24 h urinary cadmium excretion (adjusted for sex and age), brachial (p for trend  0.015) and femoral (p for trend  0.018) pulse pressure significantly decreased and femoral distensibility (p for trend  0.008) and compliance (p for trend  0.007) significantly increased with higher cadmium excretion. After full adjustment, the partial regression coefficients confirmed these associations. Pulse wave velocity (β  −0.79±0.27; p  0.004) and carotid (β  −4.20±1.51; p  0.006), brachial (β  −5.43±1.41; p  0.001) and femoral (β  −4.72±1.74; p  0.007) pulse pressures correlated negatively, whereas femoral compliance (β  0.11±0.05; p  0.016) and distensibility (β  1.70±0.70; p  0.014) correlated positively with cadmium excretion.Conclusion:Increased cadmium body burden is associated with lower aortic pulse wave velocity, lower pulse pressure throughout the arterial system, and higher femoral distensibility.
Occupation and bladder cancer in a hospital-based case–control study in Spain
Authors: Samanic C M , Kogevinas M , Silverman D T , Tardón A , Serra C , Malats N , Real F X , Carrato A , García-Closas R , Sala M , Lloreta J , Rothman N , Dosemeci M 
Published: October 2007

Objectives:We investigated the association between occupation and bladder cancer in a hospital-based case–control study conducted in Spain.Methods:1219 patients with transitional cell carcinoma of the urinary bladder and 1271 controls selected from 18 hospitals in Spain between June 1998 and September 2000 provided detailed information on life-time occupational history, smoking habits, medical history, and other factors. We used unconditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) for each occupation and industry, adjusting for age, hospital region, smoking duration, and employment in a high-risk occupation for bladder cancer.Results:Statistically significant increased risks were observed among men employed as machine operators in the printing industry (OR 5.4; 95% CI 1.6 to 17.7), among men employed in the transportation equipment industry (OR 1.6; 95% CI 1.1 to 2.6) and among those who had worked for ⩾10 years in the electrical/gas/sanitary services (OR 3.9; 95% CI 1.5 to 10.4) and in hotels and other lodgings (OR 3.1; 95% CI 1.3 to 7.3). Men who worked as miscellaneous mechanics and repairers (OR 2.0; 95% CI 1.1 to 3.6) and as supervisors in production occupations (OR 2.1; 95% CI 1.2 to 3.6) also had excess risks for bladder cancer. Male farmers and those who worked in crop and livestock production had decreased risks for bladder cancer. We found no significant associations between occupation or industry and bladder cancer risk among women.Conclusions:We did not observe excess bladder cancer risk for many of the occupations identified as being a priori at high risk. Examination of more detailed job exposure information should help clarify these associations.