bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lysogeny and Sporulation in
Bacillus
Isolates from the Gulf of Mexico
Authors: Mobberley Jennifer , Authement R. Nathan , Segall Anca M. , Edwards Robert A. , Slepecky R. A. , Paul J. H. 
Published: December 2009

ABSTRACT

Eleven
Bacillus
isolates from the surface and subsurface waters of the Gulf of Mexico were examined for their capacity to sporulate and harbor prophages. Occurrence of sporulation in each isolate was assessed through decoyinine induction, and putative lysogens were identified by prophage induction by mitomycin C treatment. No obvious correlation between ability to sporulate and prophage induction was found. Four strains that contained inducible virus-like particles (VLPs) were shown to sporulate. Four strains did not produce spores upon induction by decoyinine but contained inducible VLPs. Two of the strains did not produce virus-like particles or sporulate significantly upon induction. Isolate B14905 had a high level of virus-like particle production and a high occurrence of sporulation and was further examined by genomic sequencing in an attempt to shed light on the relationship between sporulation and lysogeny.
In silico
analysis of the B14905 genome revealed four prophage-like regions, one of which was independently sequenced from a mitomycin C-induced lysate. Based on PCR and transmission electron microscopy (TEM) analysis of an induced phage lysate, one is a noninducible phage remnant, one may be a defective phage-like bacteriocin, and two were inducible prophages. One of the inducible phages contained four putative transcriptional regulators, one of which was a SinR-like regulator that may be involved in the regulation of host sporulation. Isolates that both possess the capacity to sporulate and contain temperate phage may be well adapted for survival in the oligotrophic ocean.
Stability of a
Spodoptera frugiperda
Nucleopolyhedrovirus Deletion Recombinant during Serial Passage in Insects
Authors: Simón Oihane , Williams Trevor , Possee Robert D. , López-Ferber Miguel , Caballero Primitivo 
Published: December 2009

ABSTRACT

The stabilities of the
Spodoptera frugiperda
multiple nucleopolyhedrovirus (SfMNPV) complete genome bacmid (Sfbac) and a deletion recombinant (Sf29null) in which the
Sf29
gene was replaced by a kanamycin resistance cassette were determined during sequential rounds of
per os
infection in insect larvae. The
Sf29
gene is a viral factor that determines the number of virions in occlusion bodies (OBs). The Sf29null bacmid virus was able to recover the
Sf29
gene during passage. After the third passage (P3) of Sf29null bacmid OBs, the population was observed to reach an equilibrium involving a mixture of those with a kanamycin resistance cassette and those with the
Sf29
gene. The biological activity of Sf29null bacmid OBs at P3 was similar to that of Sfbac OBs. The recovered gene in the Sf29null virus was 98 to 100% homologous to the
Sf29
genes of different SfMNPV genotypes. Reverse transcription-PCR analysis of uninoculated
S. frugiperda
larvae confirmed the expression of the SfMNPV
ie-0
and
Sf29
genes, indicating that the insect colony harbors a covert SfMNPV infection. Additionally, the nonessential bacterial artificial chromosome vector was spontaneously deleted from both viral genomes upon passage in insects.
Iron Regulation through the Back Door: Iron-Dependent Metabolite Levels Contribute to Transcriptional Adaptation to Iron Deprivation in Saccharomyces cerevisiae
Authors: Ihrig Jessica , Hausmann Anja , Hain Anika , Richter Nadine , Hamza Iqbal , Lill Roland , Mühlenhoff Ulrich 
Published: December 2009

ABSTRACT

Budding yeast (
Saccharomyces cerevisiae
) responds to iron deprivation both by Aft1-Aft2-dependent transcriptional activation of genes involved in cellular iron uptake and by Cth1-Cth2-specific degradation of certain mRNAs coding for iron-dependent biosynthetic components. Here, we provide evidence for a novel principle of iron-responsive gene expression. This regulatory mechanism is based on the modulation of transcription through the iron-dependent variation of levels of regulatory metabolites. As an example, the
LEU1
gene of branched-chain amino acid biosynthesis is downregulated under iron-limiting conditions through depletion of the metabolic intermediate α-isopropylmalate, which functions as a key transcriptional coactivator of the Leu3 transcription factor. Synthesis of α-isopropylmalate involves the iron-sulfur protein Ilv3, which is inactivated under iron deficiency. As another example, decreased mRNA levels of the cytochrome
c
-encoding
CYC1
gene under iron-limiting conditions involve heme-dependent transcriptional regulation via the Hap1 transcription factor. Synthesis of the iron-containing heme is directly correlated with iron availability. Thus, the iron-responsive expression of genes that are downregulated under iron-limiting conditions is conferred by two independent regulatory mechanisms: transcriptional regulation through iron-responsive metabolites and posttranscriptional mRNA degradation. Only the combination of the two processes provides a quantitative description of the response to iron deprivation in yeast.
WD Repeat Domain of Dictyostelium Myosin Heavy Chain Kinase C Functions in both Substrate Targeting and Cellular Localization
Authors: Franklin Atiya , Hyatt Linzi , Chowdhury Alyssa , Steimle Paul A. 
Published: December 2009

ABSTRACT

Myosin II disassembly in
Dictyostelium discoideum
is regulated by three structurally related myosin heavy chain kinases (myosin II heavy chain kinase A [MHCK-A], -B, and -C). We show that the WD repeat domain of MHCK-C is unique in that it mediates both substrate targeting and subcellular localization, revealing a target for regulation that is distinct from those of the other MHCKs.
Defects in DNA Lesion Bypass Lead to Spontaneous Chromosomal Rearrangements and Increased Cell Death
Authors: Schmidt Kristina H. , Viebranz Emilie B. , Harris Lorena B. , Mirzaei-Souderjani Hamed , Syed Salahuddin , Medicus Robin 
Published: December 2009

ABSTRACT

Rev3 polymerase and Mph1 DNA helicase participate in error-prone and error-free pathways, respectively, for the bypassing of template lesions during DNA replication. Here we have investigated the role of these pathways and their genetic interaction with recombination factors, other nonreplicative DNA helicases, and DNA damage checkpoint components in the maintenance of genome stability, viability, and sensitivity to the DNA-damaging agent methyl methanesulfonate (MMS). We find that cells lacking Rev3 and Mph1 exhibit a synergistic, Srs2-dependent increase in the rate of accumulating spontaneous, gross chromosomal rearrangements, suggesting that the suppression of point mutations by deletion of
REV3
may lead to chromosomal rearrangements. While
mph1Δ
is epistatic to homologous recombination (HR) genes, both Rad51 and Rad52, but not Rad59, are required for normal growth of the
rev3Δ
mutant and are essential for survival of
rev3Δ
cells during exposure to MMS, indicating that Mph1 acts in a Rad51-dependent, Rad59-independent subpathway of HR-mediated lesion bypass. Deletion of
MPH1
helicase leads to synergistic DNA damage sensitivity increases in cells with
chl1Δ
or
rrm3Δ
helicase mutations, whereas
mph1Δ
is hypostatic to
sgs1Δ
. Previously reported slow growth of
mph1Δ srs2Δ
cells is accompanied by G
2
/M arrest and fully suppressed by disruption of the Mec3-dependent DNA damage checkpoint. We propose a model for replication fork rescue mediated by translesion DNA synthesis and homologous recombination that integrates the role of Mph1 in unwinding D loops and its genetic interaction with Rev3 and Srs2-regulated pathways in the suppression of spontaneous genome rearrangements and in mutation avoidance.
GPR11, a Putative Seven-Transmembrane G Protein-Coupled Receptor, Controls Zoospore Development and Virulence of Phytophthora sojae
Authors: Wang Yonglin , Li Aining , Wang Xiaoli , Zhang Xin , Zhao Wei , Dou Daolong , Zheng Xiaobo , Wang Yuanchao 
Published: December 2009

ABSTRACT

G protein-coupled receptors (GPCRs) represent a large receptor family involved in a broad spectrum of cell signaling. To understand signaling mechanisms mediated by GPCRs in
Phytophthora sojae
, we identified and characterized the
PsGPR11
gene, which encodes a putative seven-transmembrane GPCR. An expression analysis revealed that
PsGPR11
was differentially expressed during asexual development. The highest expression level occurred in zoospores and was upregulated during early infection.
PsGPR11
-deficienct transformants were obtained by gene silencing strategies. Silenced transformants exhibited no differences in hyphal growth or morphology, sporangium production or size, or mating behavior. However, the release of zoospores from sporangia was severely impaired in the silenced transformants, and about 50% of the sporangia did not completely release their zoospores. Zoospore encystment and germination were also impaired, and zoospores of the transformants lost their pathogenicity to soybean. In addition, no interaction was observed between PsGPR11 and PsGPA1 with a conventional yeast two-hybrid assay, and the transcriptional levels of some genes which were identified as being negatively regulated by PsGPA1 were not clearly altered in
PsGPR11
-silenced mutants. These results suggest that
PsGPR11
-mediated signaling controls
P. sojae
zoospore development and virulence through the pathways independent of G protein.
Protein Localization in
Escherichia coli
Cells: Comparison of the Cytoplasmic Membrane Proteins ProP, LacY, ProW, AqpZ, MscS, and MscL
Authors: Romantsov Tatyana , Battle Andrew R. , Hendel Jenifer L. , Martinac Boris , Wood Janet M. 
Published: December 2009

ABSTRACT

Fluorescence microscopy has revealed that the phospholipid cardiolipin (CL) and FlAsH-labeled transporters ProP and LacY are concentrated at the poles of
Escherichia coli
cells. The proportion of CL among
E. coli
phospholipids can be varied
in vivo
as it is decreased by
cls
mutations and it increases with the osmolality of the growth medium. In this report we compare the localization of CL, ProP, and LacY with that of other cytoplasmic membrane proteins. The proportion of cells in which FlAsH-labeled membrane proteins were concentrated at the cell poles was determined as a function of protein expression level and CL content. Each tagged protein was expressed from a pBAD24-derived plasmid; tagged ProP was also expressed from the chromosome. The osmosensory transporter ProP and the mechanosensitive channel MscS concentrated at the poles at frequencies correlated with the cellular CL content. The lactose transporter LacY was found at the poles at a high and CL-independent frequency. ProW (a component of the osmoregulatory transporter ProU), AqpZ (an aquaporin), and MscL (a mechanosensitive channel) were concentrated at the poles in a minority of cells, and this polar localization was CL independent. The frequency of polar localization was independent of induction (at arabinose concentrations up to 1 mM) for proteins encoded by pBAD24-derived plasmids. Complementation studies showed that ProW, AqpZ, MscS, and MscL remained functional after introduction of the FlAsH tag (CCPGCC). These data suggest that CL-dependent polar localization in
E. coli
cells is not a general characteristic of transporters, channels, or osmoregulatory proteins. Polar localization can be frequent and CL independent (as observed for LacY), frequent and CL dependent (as observed for ProP and MscS), or infrequent (as observed for AqpZ, ProW, and MscL).
Comparative Genomics and Transduction Potential of
Enterococcus faecalis
Temperate Bacteriophages
Authors: Yasmin Azra , Kenny John G. , Shankar Jayendra , Darby Alistair C. , Hall Neil , Edwards Clive , Horsburgh Malcolm J. 
Published: December 2009

ABSTRACT

To determine the relative importance of temperate bacteriophage in the horizontal gene transfer of fitness and virulence determinants of
Enterococcus faecalis
, a panel of 47 bacteremia isolates were treated with the inducing agents mitomycin C, norfloxacin, and UV radiation. Thirty-four phages were purified from culture supernatants and discriminated using pulsed-field gel electrophoresis (PFGE) and restriction mapping. From these analyses the genomes of eight representative phages were pyrosequenced, revealing four distinct groups of phages. Three groups of phages, ΦFL1 to 3, were found to be sequence related, with ΦFL1A to C and ΦFL2A and B sharing the greatest identity (87 to 88%), while ΦFL3A and B share 37 to 41% identity with ΦFL1 and 2. ΦFL4A shares 3 to 12% identity with the phages ΦFL1 to 3. The ΦFL3A and B phages possess a high DNA sequence identity with the morphogenesis and lysis modules of
Lactococcus lactis
subsp.
cremoris
prophages. Homologs of the
Streptococcus mitis
platelet binding phage tail proteins, PblA and PblB, are encoded on each sequenced
E. faecalis
phage. Few other phage genes encoding potential virulence functions were identified, and there was little evidence of carriage of lysogenic conversion genes distal to endolysin, as has been observed with genomes of many temperate phages from the opportunist pathogens
Staphylococcus aureus
and
Streptococcus pyogenes
.
E. faecalis
JH2-2 lysogens were generated using the eight phages, and these were examined for their relative fitness in
Galleria mellonella
. Several lysogens exhibited different effects upon survival of
G. mellonella
compared to their isogenic parent. The eight phages were tested for their ability to package host DNA, and three were shown to be very effective for generalized transduction of naive host cells of the laboratory strains OG1RF and JH2-2.
Genetic Analysis of the Regulation of Type IV Pilus Function by the Chp Chemosensory System of
Pseudomonas aeruginosa
Authors: Bertrand Jacob J. , West Joyce T. , Engel Joanne N. 
Published: December 2009

ABSTRACT

The virulence of the opportunistic pathogen
Pseudomonas aeruginosa
involves the coordinate expression of many virulence factors, including type IV pili, which are required for colonization of host tissues and for twitching motility. Type IV pilus function is controlled in part by the Chp chemosensory system, which includes a histidine kinase, ChpA, and two CheY-like response regulators, PilG and PilH. How the Chp components interface with the type IV pilus motor proteins PilB, PilT, and PilU is unknown. We present genetic evidence confirming the role of ChpA, PilG, and PilB in the regulation of pilus extension and the role of PilH and PilT in regulating pilus retraction. Using informative double and triple mutants, we show that (i) ChpA, PilG, and PilB function upstream of PilH, PilT, and PilU; (ii) that PilH enhances PilT function; and (iii) that PilT and PilB retain some activity in the absence of signaling input from components of the Chp system. By site-directed mutagenesis, we demonstrate that the histidine kinase domain of ChpA and the phosphoacceptor sites of both PilG and PilH are required for type IV pilus function, suggesting that they form a phosphorelay system important in the regulation of pilus extension and retraction. Finally, we present evidence suggesting that
pilA
transcription is regulated by intracellular PilA levels. We show that PilA is a negative regulator of
pilA
transcription in
P. aeruginosa
and that the Chp system functionally regulates
pilA
transcription by controlling PilA import and export.
ExsD Inhibits Expression of thePseudomonas aeruginosaType III Secretion System by Disrupting ExsA Self-Association and DNA Binding Activity
Authors: Brutinel Evan D. , Vakulskas Christopher A. , Yahr Timothy L. 
Published: December 2009

ABSTRACTPseudomonas aeruginosautilizes a type III secretion system (T3SS) to damage eukaryotic host cells and evade phagocytosis. Transcription of the T3SS regulon is controlled by ExsA, a member of the AraC/XylS family of transcriptional regulators. ExsA-dependent transcription is coupled to type III secretory activity through a cascade of three interacting proteins (ExsC, ExsD, and ExsE). Genetic data suggest that ExsD functions as an antiactivator by preventing ExsA-dependent transcription, ExsC functions as an anti-antiactivator by binding to and inhibiting ExsD, and ExsE binds to and inhibits ExsC. T3SS gene expression is activated in response to low-calcium growth conditions or contact with host cells, both of which trigger secretion of ExsE. In the present study we reconstitute the T3SS regulatory cascadein vitrousing purified components and find that the ExsD·ExsA complex lacks DNA binding activity. As predicted by the genetic data, ExsC addition dissociates the ExsD·ExsA complex through formation of an ExsD·ExsC complex, thereby releasing ExsA to bind T3SS promoters and activate transcription. Addition of ExsE to the purified system results in formation of the ExsE·ExsC complex and prevents ExsC from dissociating the ExsD·ExsA complex. Although purified ExsA is monomeric in solution, bacterial two-hybrid analyses demonstrate that ExsA can self-associate and that ExsD inhibits self-association of ExsA. Based on these data we propose a model in which ExsD regulates ExsA-dependent transcription by inhibiting the DNA-binding and self-association properties of ExsA.
Complete Genome Sequence of the Wild-Type Commensal
Escherichia coli
Strain SE15, Belonging to Phylogenetic Group B2
Authors: Toh Hidehiro , Oshima Kenshiro , Toyoda Atsushi , Ogura Yoshitoshi , Ooka Tadasuke , Sasamoto Hiroyuki , Park Sang-Hee , Iyoda Sunao , Kurokawa Ken , Morita Hidetoshi , Itoh Kikuji , Taylor Todd D. , Hayashi Tetsuya , Hattori Masahira 
Published: December 2009

ABSTRACT

Escherichia coli
SE15 (O150:H5) is a human commensal bacterium recently isolated from feces of a healthy adult and classified into
E. coli
phylogenetic group B2, which includes the majority of extraintestinal pathogenic
E. coli
. Here, we report the finished and annotated genome sequence of this organism.
The effects of smoking and smoking cessation on mortality from cardiovascular disease among Japanese: pooled analysis of three large-scale cohort studies in Japan
Authors: Honjo Kaori , Iso Hiroyasu , Tsugane Shoichiro , Tamakoshi Akiko , Satoh Hiroshi , Tajima Kazuo , Suzuki Takaichiro , Sobue Tomotaka 
Published: December 2009

ObjectivesTo estimate the gender-specific risk of mortality from cardiovascular disease according to smoking status and time since smoking cessation among former smokers in Japan.DesignProspective study.Setting140 026 males and 156 810 females aged 40–79 years who participated in one of three cohort studies conducted in Japan between 1980 and 1990.OutcomeThe gender-specific hazard ratios (HRs) for cardiovascular disease mortality were calculated after adjustment for age and cohort.ResultsThe age-adjusted and cohort-adjusted HRs for current smokers compared with lifelong non-smokers were 1.51 (95% CI 1.38 to 1.64) for total cardiovascular diseases, 2.19 (95% CI 1.79 to 2.67) for coronary heart disease and 1.24 (95% CI 1.10 to 1.41) for total stroke in males, and were 1.85 (95% CI 1.65 to 2.06), 2.84 (95% CI 2.24 to 3.60) and 1.70 (95% CI 1.44 to 2.01), respectively, in females. The age-adjusted and cohort-adjusted HRs for former smokers compared with current smokers according to the time period since smoking cessation decreased by approximately 5 years after smoking cessation and reached the same level as lifelong non-smokers approximately 10 years after smoking cessation among both males and females.ConclusionsThe present study confirmed the association between smoking and mortality from cardiovascular disease in both males and females. Smoking cessation is a crucial preventive measure against death from cardiovascular disease.
Regional differences in awareness of tobacco advertising and promotion in China: findings from the ITC China Survey
Authors: Yang Yan , Li Lin , Yong Hua-Hie , Borland Ron , Wu Xi , Li Qiang , Wu Changbao , Foong Kin 
Published: December 2009

ObjectiveTo examine whether levels of, and factors related to, awareness of tobacco advertising and promotion differ across six cities in China.MethodsData from wave 1 of the International Tobacco Control (ITC) China Survey (April to August 2006) were analysed. The ITC China Survey employed a multistage sampling design in Beijing, Shenyang, Shanghai, Changsha, Guangzhou and Yinchuan. Face-to-face interviews were conducted with a total of 4763 smokers and 1259 non-smokers. Multivariate logistic regression models were used to identify factors associated with awareness of tobacco advertising and promotion.ResultsThe overall levels of noticing advertisements varied considerably by city. Cities reporting lower levels of advertising tended to report higher levels of point of sale activity. Noticing tobacco industry promotions was associated with more positive attitudes to tobacco companies.ConclusionThe awareness of tobacco advertising and promotional activities was not homogeneous across the six Chinese cities, suggesting variations in the tobacco industry's activities and the diversity of implementing a central set of laws to restrict tobacco promotion. This study clearly demonstrates the need to work with the implementation agencies if national laws are to be properly enforced.
A cross-sectional study on levels of second-hand smoke in restaurants and bars in five cities in China
Authors: Liu R L , Yang Y , Travers M J , Fong G T , O'Connor R J , Hyland A , Li L , Nan Y , Feng G Z , Li Q , Jiang Y 
Published: December 2009

ObjectivesTo assess indoor second-hand smoke (SHS) exposure in restaurants and bars via PM2.5(fine particles 2.5 μm in diameter and smaller) level measurements in five cities in China.MethodsThe study was conducted from July to September in 2007 in Beijing, Xi'an, Wuhan, Kunming and Guiyang. Portable aerosol monitors were used to measure PM2.5concentrations in 404 restaurants and bars. The occupant density and the active smoker density were calculated for each venue sampled.ResultsAmong the 404 surveyed venues, 23 had complete smoking bans, 9 had partial smoking bans and 313 (77.5%) were observed to have allowed smoking during sampling. The geometric mean of indoor PM2.5levels in venues with smoking observed was 208 μg/m3and 99 μg/m3in venues without observed smoking. When outdoor PM2.5levels were adjusted, indoor PM2.5levels in venues with smoking observed were consistently significantly higher than in venues without smoking observed (F=80.49, p<0.001). Indoor PM2.5levels were positively correlated with outdoor PM2.5levels (partial rho=0.37 p<0.001) and active smoker density (partial rho=0.34, p<0.001).ConclusionsConsistent with findings in other countries, PM2.5levels in smoking places are significantly higher than those in smoke-free places and are strongly related to the number and density of active smokers. These findings document the high levels of SHS in hospitality venues in China and point to the urgent need for comprehensive smoke-free laws in China to protect the public from SHS hazards, as called for in Article 8 of the Framework Convention on Tobacco Control, which was ratified by China in 2005.