bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Corticosteroids and Neuropeptides on the Expression of Defensins in Bovine Tracheal Epithelial Cells
Authors: Mitchell Gordon B. , Al-Haddawi Muthafar H. , Clark Mary Ellen , Beveridge Jennifer D. , Caswell Jeff L.
Published: December 2006

Susceptibility to bacterial pneumonia in cattle is enhanced by stressors such as transportation, weaning, and commingling, which trigger a physiologic stress response resulting in elevated levels of endogenous corticosteroids and catecholamines. To determine the effect of neuroendocrine mediators on the expression of innate defense peptides in the lung, bovine tracheal epithelial cells were exposed to dexamethasone, catecholamines, acetylcholine, or substance P, and then β-defensin expression was quantified using real-time reverse transcription-PCR. Basal expression of tracheal antimicrobial peptide (TAP) mRNA was not affected by any of the mediators tested. However, induction of TAP expression by lipopolysaccharide was significantly inhibited by pretreatment with dexamethasone. Bronchial biopsy specimens from dexamethasone-treated calves had significantly lower expression of TAP and lingual antimicrobial peptide (LAP) mRNA than saline-treated controls following 48 h of treatment. Lipopolysaccharide-elicited neutrophil recruitment was enhanced in the lungs of dexamethasone-treated calves compared to saline-treated controls. These findings indicate that modulation of epithelial antimicrobial peptide expression is one mechanism through which corticosteroids and stress may impair innate pulmonary defenses.
SseL Is a
Salmonella
-Specific Translocated Effector Integrated into the SsrB-Controlled
Salmonella
Pathogenicity Island 2 Type III Secretion System
Authors: Coombes Brian K. , Lowden Michael J. , Bishop Jennifer L. , Wickham Mark E. , Brown Nat F. , Duong Nancy , Osborne Suzanne , Gal-Mor Ohad , Finlay B. Brett
Published: December 2006

Bacterial pathogens use horizontal gene transfer to acquire virulence factors that influence host colonization, alter virulence traits, and ultimately shape the outcome of disease following infection. One hallmark of the host-pathogen interaction is the prokaryotic type III secretion system that translocates virulence factors into host cells during infection.
Salmonella enterica
possesses two type III secretion systems that are utilized during host colonization and intracellular replication.
Salmonella
pathogenicity island 2 (SPI2) is a genomic island containing approximately 30 contiguous genes required to assemble a functional secretion system including the two-component regulatory system called SsrA-SsrB that positively regulates transcription of the secretion apparatus. We used transcriptional profiling with DNA microarrays to search for genes that coregulate with the SPI2 type III secretion machinery in an SsrB-dependent manner. Here we report the identification of a
Salmonella
-specific translocated effector called SseL that is required for full virulence during murine typhoid-like disease. Analysis of infected macrophages using fluorescence-activated cell sorting revealed that
sseL
is induced inside cells and requires SsrB for expression. SseL is retained predominantly in the cytoplasm of infected cells following translocation by the type III system encoded in SPI2. Animal infection experiments with
sseL
mutant bacteria indicate that integration of SseL into the SsrB response regulatory system contributes to systemic virulence of this pathogen.
Evaluation of the Ability of
Streptococcus agalactiae
Strains Isolated from Genital and Neonatal Specimens To Bind to Human Fibrinogen and Correlation with Characteristics of the
fbsA
and
fbsB
Genes
Authors: Rosenau Agnès , Martins Karine , Amor Souheila , Gannier François , Lanotte Philippe , van der Mee-Marquet Nathalie , Mereghetti Laurent , Quentin Roland
Published: December 2006

The ability of 111
Streptococcus agalactiae
strains to bind to human fibrinogen was quantified. We correlated the percentages of bacteria that bound to immobilized fibrinogen with fibrinogen-binding (
fbs
) gene characteristics of strains and with clinical origin, serotypes, and phylogenetic positions of strains. Percentages varied from 0.4 to 29.9%. Fifty-five strains (49.5%) had the
fbsB
gene sensu stricto described by Gutekunst et al. (Infect. Immun., 72:3495-3504, 2004), allowing adhesion to human fibrinogen, and all of the other strains had an
fgag
variant gene. Ninety strains (81.1%) had a
fbsA
gene and 55 of them also had the
fbsB
gene. The other 21 strains (18.9%) had a truncated form of
fbsA
without the
fbsB
gene sensu stricto. The numbers of 48-nucleotide repeat sequences (rs) in the
fbsA
gene varied from 2 to 26. The population of strains with the highest ability to bind to human fibrinogen significantly more frequently had the
fbsB
gene sensu stricto and 4 to 7 rs in the
fbsA
gene (
P
< 0.05). However, the single strain that carried the highest number of rs (26 rs) in the
fbsA
gene showed high fibrinogen-binding activity (24.3%). Strains exhibiting significantly higher levels of binding to human fibrinogen belonged to a phylogenetic group of strains associated with neonatal meningitis, currently known as the ST-17 clone, that is mostly composed of serotype III strains. These findings indicate that
S. agalactiae
strains possess a wide variety of
fbs
gene content that markedly influences the ability of strains to bind to human fibrinogen. Variations in the configuration and the expression of the Fbs proteins may therefore partly explain the variability of virulence in
S. agalactiae
species.
Characterization of Early Gamma Interferon (IFN-γ) Expression during Murine Listeriosis: Identification of NK1.1+CD11c+Cells as the Primary IFN-γ-Expressing Cells
Authors: Chang Shu-Rung , Wang Kung-Jiun , Lu Yan-Feng , Yang Lii-Jia , Chen Wei-Jie , Lin Yu-Hsiang , Chang Hsin-Hou , Wang Shih-Lien
Published: December 2006

Though it is well established that gamma interferon (IFN-γ) is crucial to the early innate defense of murine listeriosis, its sources remain controversial. In this study, intracellular cytokine staining of IFN-γ-expressing splenocytes early afterListeria monocytogenesinfection revealed that NK1.1+, CD11c+, CD8+T, and CD4+T cells expressed IFN-γ 24 h after infection. Contrary to the previous report, most IFN-γ+dendritic cells (DC) were CD8α−DC. Unexpectedly, almost all CD11c+IFN-γ-expressing cells also expressed NK1.1. These NK1.1+CD11c+cells represented primary IFN-γ-expressing cells after infection. In situ studies showed these NK1.1+CD11c+cells were recruited to the borders of infectious foci and expressed IFN-γ. A significant NK1.1+CD11c+population was found in uninfected spleen, lymph node, blood, and bone marrow cells. And its number increased significantly in spleen, lymph node, and bone marrow afterL. monocytogenesinfection. Using interleukin-12 (IL-12) p40−/−mice, IFN-γ expression was found to be largely IL-12 p40 dependent, and the number of IFN-γ-expressing cells was only about one-third of that of wild-type mice. Moreover, the IFN-γ expression was absolutely dependent on liveL. monocytogenesinfection, as no IFN-γ was detected after inoculation of heat-killedL. monocytogenes. Our findings not only provide an insight into IFN-γ expression after in vivo infection but may also change the current perceptions of DC and natural killer cells.
Apoptosis-Inducing Factor Participation in Bovine MacrophageMycobacterium bovis-Induced Caspase-Independent Cell Death
Authors: Vega-Manriquez X. , López-Vidal Y. , Moran J. , Adams L. G. , Gutiérrez-Pabello J. A.
Published: December 2006

Mycobacterium tuberculosiscomplex species survive and replicate in phagosomes of the host cell. Cell death (CD) has been highlighted as one of the probable outcomes in this host-pathogen interaction. Previously, our group demonstrated macrophage apoptosis as a consequence ofMycobacterium bovisinfection. In this study, we aimed to identify the contribution of apoptotic effector elements inM. bovis-induced CD. Bovine macrophages were either infected withM. bovis(multiplicity of infection, 10:1) or treated with anM. boviscell extract (CFE). Structural changes compatible with CD were evaluated. Chromatin condensation was increased three times by the CFE. On the other hand, a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay demonstrated that levels of DNA fragmentation induced byM. bovisand CFE were 53.7% ± 24% and 38.9% ± 14%, respectively, whereas control cells had a basal proportion of 8.9% ± 4.1%. Rates of DNA fragmentation were unaffected by the presence of the pan-caspase inhibitorN-benzyloxycarbonyl-Val-Ala-Asp (z-VAD). Cells treated with 100 μg of CFE for 12 h had a fivefold decrease in the level of mitochondrial outer membrane permeabilization compared to that of untreated cells. NeitherM. bovisinfection nor CFE treatment induced activation of caspase 3, 8, or 9. Translocation of apoptosis-inducing factor (AIF) to the nucleus was identified in 32% ± 3.5% and 26.3% ± 4.9% ofM. bovis-infected and CFE-treated cells, respectively. Incubation of macrophages with z-VAD prior to infection did not alter the percentage of cells showing AIF translocation. Our data suggest thatM. bovis-induced CD in bovine macrophages is caspase independent with AIF participation.
Isolation and Characterization of Biofilm Formation-Defective Mutants of
Staphylococcus aureus
Authors: Tu Quoc Patrick H. , Genevaux Pierre , Pajunen Maria , Savilahti Harri , Georgopoulos Costa , Schrenzel Jacques , Kelley William L.
Published: December 2006

Staphylococcus aureus
produces biofilm and this mode of colonization facilitates infections that are often difficult to treat and engender high morbidity and mortality. We have exploited bacteriophage Mu transposition methods to create an insertional mutant library in a highly biofilm-forming
S. aureus
clinical isolate. Our screen identified 38 insertions in 23 distinct genes together with one intergenic region that significantly reduced biofilm formation. Nineteen insertions were mapped in loci not previously known to affect biofilm in this organism. These include insertions in
codY
,
srrA
,
mgrA
, and
fmtA
, a putative DEAD-box helicase, two members of the zinc-metallo-β lactamase/β-CASP family, and a hypothetical protein with a GGDEF motif. Fifteen insertions occurred in the
icaADBC
operon, which produces intercellular adhesion antigen (PIA) and is important for biofilm formation in many strains of
S. aureus
and
Staphylococcus epidermidis
. Obtaining a high proportion of independent Em-Mu disruptions in
icaADBC
demonstrated both the importance of PIA for biofilm formation in this clinical strain and the strong validation of the screening procedure that concomitantly uncovered additional mutants. All non-
ica
mutants were further analyzed by immunoblotting and biochemical fractionation for perturbation of PIA and wall teichoic acid. PIA levels were diminished in the majority of non-
ica
insertional mutants. Three mutant strains were chosen and were functionally complemented for restored biofilm formation by transformation with plasmids carrying the cloned wild-type gene under the control of a xylose-inducible promoter. This is a comprehensive collection of biofilm-defective mutants that underscores the multifactorial genetic program underlying the establishment of biofilm in this insidious pathogen.
Toll-Like Receptor-2-Mediated C-C Chemokine Receptor 3 and Eotaxin-Driven Eosinophil Influx Induced by
Mycobacterium bovis
BCG Pleurisy
Authors: D'Ávila Heloisa , Almeida Patrícia E. , Roque Natália R. , Castro-Faria-Neto Hugo C. , Bozza Patrícia T.
Published: December 2006

An acute and persistent eosinophil infiltration is observed during
Mycobacterium bovis
BCG pleural infection in mice. Eosinophil accumulation, lipid body formation, and eotaxin production were significantly reduced in BCG-infected Toll-like receptor-2 (TLR2)-deficient mice compared to wild-type mice. Neutralization of eotaxin or CCR3 drastically inhibited BCG-induced eosinophil accumulation and lipid body formation, indicating that BCG-induced eosinophil recruitment and activation is largely dependent of TLR2-mediated eotaxin generation.
Lactate Acquisition Promotes Successful Colonization of the Murine Genital Tract byNeisseria gonorrhoeae
Authors: Exley Rachel M. , Wu Hong , Shaw Jonathan , Schneider Muriel C. , Smith Harry , Jerse Ann E. , Tang Christoph M.
Published: December 2006

Previous studies onNeisseria gonorrhoeaehave demonstrated that metabolism of lactate in the presence of glucose increases the growth rate of the bacterium and enhances its resistance to complement-mediated killing. Although these findings in vitro suggest that the acquisition of lactate promotes gonococcal colonization, the significance of this carbon source to the survival of the gonococcus in vivo remains unknown. To investigate the importance of lactate utilization duringNeisseria gonorrhoeaegenital tract infection, we identified the genelctP, which encodes the gonococcal lactate permease. A mutant that lacks a functional copy oflctPwas unable to take up exogenous lactate and did not grow in defined medium with lactate as the sole carbon source, in contrast to the wild-type and complemented strains; the mutant strain exhibited no growth defect in defined medium containing glucose. In defined medium containing physiological concentrations of lactate and glucose, thelctPmutant demonstrated reduced early growth and increased sensitivity to complement-mediated killing compared with the wild-type strain; the enhanced susceptibility to complement was associated with a reduction in lipopolysaccharide sialylation of thelctPmutant. The importance of lactate utilization during colonization was evaluated in the murine model of lower genital tract infection. ThelctPmutant was significantly attenuated in its ability to colonize and survive in the genital tract, while the complemented mutant exhibited no defect for colonization. Lactate is a micronutrient in the genital tract that contributes to the survival of the gonococcus.
PduL Is an Evolutionarily Distinct Phosphotransacylase Involved in B
12
-Dependent 1,2-Propanediol Degradation by
Salmonella enterica
Serovar Typhimurium LT2
Authors: Liu Yu , Leal Nicole A. , Sampson Edith M. , Johnson Celeste L. V. , Havemann Gregory D. , Bobik Thomas A.
Published: December 2006

Salmonella enterica
degrades 1,2-propanediol (1,2-PD) in a coenzyme B
12
-dependent manner. Previous enzymatic assays of crude cell extracts indicated that a phosphotransacylase (PTAC) was needed for this process, but the enzyme involved was not identified. Here, we show that the
pduL
gene encodes an evolutionarily distinct PTAC used for 1,2-PD degradation. Growth tests showed that
pduL
mutants were unable to ferment 1,2-PD and were also impaired for aerobic growth on this compound. Enzyme assays showed that cell extracts from a
pduL
mutant lacked measurable PTAC activity in a background that also carried a
pta
mutation (the
pta
gene was previously shown to encode a PTAC enzyme). Ectopic expression of
pduL
corrected the growth defects of a
pta
mutant. PduL fused to eight C-terminal histidine residues (PduL-His
8
) was purified, and its kinetic constants were determined: the
V
max
was 51.7 ± 7.6 μmol min
−1
mg
−1
, and the

K
m

values for propionyl-PO
4
2−
and acetyl-PO
4
2−
were 0.61 and 0.97 mM, respectively. Sequence analyses showed that PduL is unrelated in amino acid sequence to known PTAC enzymes and that PduL homologues are distributed among at least 49 bacterial species but are absent from the
Archaea
and
Eukarya
.
Detection of a Group II Intron without an Open Reading Frame in the Alpha-Toxin Gene ofClostridium perfringensIsolated from a Broiler Chicken
Authors: Ma Menglin , Ohtani Kaori , Shimizu Tohru , Misawa Naoaki
Published: December 2006

A DNA insertion of 834 bp, designated CPF-G2Im, was identified within the alpha toxin gene (cpa) ofClostridium perfringensstrain CPBC16ML, isolated from a broiler chicken. Sequence analysis of CPF-G2Im indicated that it was integrated 340 nucleotides downstream of the start codon ofcpa. However, the insertion did not abolish the phospholipase C and hemolytic activities of CPBC16ML. To investigate the expression of its alpha toxin, the intact copy ofcpawas cloned into an expression vector and transformed intoEscherichia coliM15 cells. Immunoblotting analysis showed that the protein expressed from the transformant as well as in the culture supernatant ofC. perfringensstrain CPBC16ML had the expected molecular weight detected in reference strains ofC. perfringens. Northern hybridization and reverse transcriptase PCR (RT-PCR) analysis revealed that the entire CPF-G2Im insertion was completely spliced from thecpaprecursor mRNA transcripts. The sequence of the insertion fragment has 95% and 97% identity to two noncoding regions corresponding to sequences that flank a predicted group II RT gene present in the pCPF4969 plasmid ofC. perfringens. However, an RT was not encoded by the CPF-G2Im fragment. Based on the secondary structure prediction analysis, CPF-G2Im revealed typical features of group II introns. The present study shows that CPF-G2Im is capable of splicing in bothC. perfringensandE. coli. To our knowledge, this is the first report that a group II intron without an open reading frame (ORF) is located in thecpaORF ofC. perfringens.
hpaR, a PutativemarRFamily Transcriptional Regulator, Is Positively Controlled by HrpG and HrpX and Involved in the Pathogenesis, Hypersensitive Response, and Extracellular Protease Production ofXanthomonas campestrisPathovar campestris
Authors: Wei Ke , Tang Dong-Jie , He Yong-Qiang , Feng Jia-Xun , Jiang Bo-Le , Lu Guang-Tao , Chen Baoshan , Tang Ji-Liang
Published: December 2006

The MarR family of transcriptional regulators of bacteria are involved in the regulation of many cellular processes, including pathogenesis. In this work, we have demonstrated genetically thathpaR(hpa,hrpassociated), which encodes a putative MarR family regulator, is involved in the hypersensitive response (HR), pathogenicity, and extracellular protease production of the phytopathogenic bacteriumXanthomonas campestrispathovar campestris. A mutation inhpaRresulted in complete loss of virulence in the host plant cabbage, a delayed and weakened HR in the nonhost plant pepper ECW-10R, and an increase in extracellular protease production. Detection of the β-glucuronidase activity of a plasmid-drivenhpaRpromoter-gusAreporter revealed that the expression ofhpaRis positively controlled by HrpG and HrpX and is suppressed in rich medium while being strongly induced in minimal andhrp-inducing media and inside the host. These findings indicate thathpaRbelongs to thehrpGandhrpXregulon and that HrpX regulates the extracellular protease production viahpaRinX. campestrispv. campestris.
Divergence and Redundancy of Transport and Metabolic Rate-Yield Strategies in a SingleEscherichia coliPopulation
Authors: Maharjan Ram Prasad , Seeto Shona , Ferenci Thomas
Published: December 2006

The energetic efficiency of nutrient uptake and conversion into biomass is a key factor in the ecological behavior of microorganisms. The constraints shaping the metabolic rate-yield trade-off in bacteria are not well understood. To examine whether metabolic rate-yield settings and physiological strategies evolve toward a particular optimum in a constant environment, we studied multipleEscherichia coliisolates evolving in a glucose-limited chemostat population. A major divergence in transport and metabolic strategies was observed, and the isolates included inefficient rate strategists (polluters or cheaters) and yield strategists (conservationists), as well as various hybrid rate-yield strategists and alternative ecotypes (dropouts). Sugar transport assays, strain comparisons based on metabolomics, and Biolog profiling revealed variance to the point of individuality within an evolving population. Only 68 of 177 metabolites assayed were not affected in 10 clonally related strains. The parallel enrichment of rate and yield strategists and the divergence in metabolic phylogenies indicate that bacteria do not converge on a particular rate-yield balance or unique evolutionary solutions. Redundancies in transport and metabolic pathways are proposed to have laid the framework for the multiplicity of bacterial adaptations.
Characterization of the Helicase Activity and Substrate Specificity of
Mycobacterium tuberculosis
UvrD
Authors: Curti Elena , Smerdon Stephen J. , Davis Elaine O.
Published: December 2006

UvrD is a helicase that is widely conserved in gram-negative bacteria. A
uvrD
homologue was identified in
Mycobacterium tuberculosis
on the basis of the homology of its encoded protein with
Escherichia coli
UvrD, with which it shares 39% amino acid identity, distributed throughout the protein. The gene was cloned, and a histidine-tagged form of the protein was expressed and purified to homogeneity. The purified protein had in vitro ATPase activity that was dependent upon the presence of DNA. Oligonucleotides as short as four nucleotides were sufficient to promote the ATPase activity. The DNA helicase activity of the enzyme was only fueled by ATP and dATP. UvrD preferentially unwound 3′-single-stranded tailed duplex substrates over 5′-single-stranded ones, indicating that the protein had a duplex-unwinding activity with 3′-to-5′ polarity. A 3′ single-stranded DNA tail of 18 nucleotides was required for effective unwinding. By using a series of synthetic oligonucleotide substrates, we demonstrated that
M. tuberculosis
UvrD has an unwinding preference towards nicked DNA duplexes and stalled replication forks, representing the likely sites of action in vivo. The potential role of
M. tuberculosis
UvrD in maintenance of bacterial genomic integrity makes it a promising target for drug design against
M. tuberculosis
.
Probing the In Vivo Dynamics of Type I Protein Secretion Complex Association through Sensitivity to Detergents
Authors: Cescau Sandra , Debarbieux Laurent , Wandersman Cécile
Published: December 2006

The
Serratia marcescens
hemophore is secreted by a type I secretion system consisting of three proteins: a membrane ABC protein, an adaptor protein, and the TolC-like outer membrane protein. Assembly of these proteins is induced by substrate binding to the ABC protein. Here we show that a hemophore mutant lacking the last 14 C-terminal amino acids is not secreted but rather interacts with the ABC protein and promotes a stable multiprotein complex. Strains expressing the transporter and the mutant protein are sensitive to detergents (sodium dodecyl sulfate [SDS]). TolC is trapped in the transporter jammed by the truncated substrate and therefore is not present at sufficient concentrations to allow the efflux pumps to expel detergents. Using an SDS sensitivity assay, we showed that the hemophore interacts with the ABC protein via two nonoverlapping sites. We also demonstrated that the C-terminal peptide, which functions as an intramolecular signal sequence in the complete substrate, may also have intermolecular activity and triggers complex dissociation in vivo when it is provided as a distinct peptide. The SDS sensitivity test on plates enables workers to study type I secretion protein association and dissociation independent of the secretion process itself.
SwmB, a 1.12-Megadalton Protein That Is Required for Nonflagellar Swimming Motility in
Synechococcus
Authors: McCarren J. , Brahamsha B.
Published: December 2006

SwmB is required for swimming motility in
Synechococcus
sp. strain WH8102. This highly repetitive 1.12-MDa polypeptide is associated with the cell surface, where it is arranged in a punctate manner. Inactivation of
swmB
does not affect the localization of SwmA, an S-layer protein also required for swimming.
An Active Nonautonomous Mobile Element in
Sulfolobus islandicus
REN1H1
Authors: Berkner Silvia , Lipps Georg
Published: December 2006

In the crenarchaeote
Sulfolobus islandicus
REN1H1, a mobile element of 321 bp length has been shown to be active. It does not contain terminal inverted repeats and transposes by a replicative mechanism. This newly discovered element has been named SMN1 (for
Sulfolobus
miniature noninverted repeat transposable element).
Amino Acid Residues Required for Maturation, Cell Uptake, and Processing of Translation Inhibitor Microcin C
Authors: Kazakov Teymur , Metlitskaya Anastasia , Severinov Konstantin
Published: December 2006

Microcin C (McC), a peptide-nucleotide Trojan horse antibiotic, targets aspartyl-tRNA synthetase. We present the results of a systematic mutational study of the 7-amino-acid ribosomally synthesized peptide moiety of McC. Our results define amino acid positions important for McC maturation and cell uptake and processing and open the way for creation of more potent McC-based inhibitors.
The SXT Conjugative Element and Linear Prophage N15 Encode Toxin-Antitoxin-Stabilizing Systems Homologous to the
tad-ata
Module of the
Paracoccus aminophilus
Plasmid pAMI2
Authors: Dziewit Lukasz , Jazurek Magdalena , Drewniak Lukasz , Baj Jadwiga , Bartosik Dariusz
Published: December 2006

A group of proteic toxin-antitoxin (TA) cassettes whose representatives are widely distributed among bacterial genomes has been identified. These cassettes occur in chromosomes, plasmids, bacteriophages, and noncomposite transposons, as well as in the SXT conjugative element of
Vibrio cholerae
. The following four homologous loci were subjected to detailed comparative studies: (i)
tad-ata
from plasmid pAMI2 of
Paracoccus aminophilus
(the prototype of this group), (ii)
gp49-gp48
from the linear bacteriophage N15 of
Escherichia coli
, (iii) s045-s044 from SXT, and (iv) Z3230-Z3231 from the genomic island of enterohemorrhagic
Escherichia coli
O157:H7 strain EDL933. Functional analysis revealed that all but one of these loci (Z3230-Z3231) are able to stabilize heterologous replicons, although the host ranges varied. The TA cassettes analyzed have the following common features: (i) the toxins are encoded by the first gene of each operon; (ii) the antitoxins contain a predicted helix-turn-helix motif of the XRE family; and (iii) the cassettes have two promoters that are different strengths, one which is located upstream of the toxin gene and one which is located upstream of the antitoxin gene. All four toxins tested are functional in
E. coli
; overexpression of the toxins (in the absence of antitoxin) results in a bacteriostatic effect manifested by elongation of bacterial cells and growth arrest. The toxins have various effects on cell viability, which suggests that they may recognize different intracellular targets. Preliminary data suggest that different cellular proteases are involved in degradation of antitoxins encoded by the loci analyzed.
The Number of G Residues in the
Bacillus subtilis pyrG
Initially Transcribed Region Governs Reiterative Transcription-Mediated Regulation
Authors: Elsholz Alexander K. W. , Jørgensen Casper Møller , Switzer Robert L.
Published: December 2006

Derepression of
pyrG
expression in
Bacillus subtilis
involves CTP-sensitive reiterative transcription, which introduces up to 11 extra G residues at the 5′ ends of
pyrG
transcripts. Insertion of three or more additional Gs at the 5′ end of the
pyrG
initially transcribed region abolished reiterative transcription and caused constitutive expression.
Isolation and Characterization of Dominant Mutations in theBacillus subtilisStressosome Components RsbR and RsbS
Authors: Reeves Adam , Haldenwang W. G.
Published: December 2006

The general stress response ofBacillus subtilisis controlled by the activity state of the σBtranscription factor. Physical stress is communicated to σBvia a large-molecular-mass (>106-Da) structure (the stressosome) formed by one or more members of a family of homologous proteins (RsbR, YkoB, YojH, YqhA). The positive regulator (RsbT) of the σBstress induction pathway is incorporated into the complex bound to an inhibitor protein (RsbS). Exposure to stress empowers an RsbT-dependent phosphorylation of RsbR and RsbS, with the subsequent release of RsbT to activate downstream processes. The mechanism by which stress initiates these reactions is unknown. In an attempt to identify changes in stressosome components that could lead to σBactivation, a DNA segment encoding these proteins was mutagenized and placed intoB. subtilisto create a merodiploid strain for these genes. Eight mutations that allowed heightened σBactivity in the presence of their wild-type counterparts were isolated. Two of the mutations are missense changes inrsbR, and six are amino acid changes inrsbS. Additional experiments suggested that both of thersbRmutations and three of thersbSmutations likely enhance σBactivity by elevating the level of RsbS phosphorylation. All of the mutations were found to be dominant over wild-type alleles only when they are cotranscribed within anrsbR rsbS rsbToperon. The data suggest that changes in RsbR can initiate the downstream events that lead to σBactivation and that RsbR, RsbS, and RsbT likely interact with each other concomitantly with their synthesis.
Autoregulation Is Essential for Precise Temporal and Steady-State Regulation by theBordetellaBvgAS Phosphorelay
Authors: Williams Corinne L. , Cotter Peggy A.
Published: December 2006

TheBordetellaBvgAS virulence control system is prototypical of phosphorelays that use a polydomain sensor and a response regulator to control gene expression in response to environmental cues. BvgAS controls the expression of at least three distinct phenotypic phases (Bvg−, Bvgi, and Bvg+) by differentially regulating the expression of at least four classes of genes. Among the loci regulated by BvgAS isbvgASitself. We investigated the role of autoregulation in the ability of BvgAS to control multiple gene expression patterns in a temporal and steady-state manner by constructingBordetella bronchisepticastrains in which thebvgASpromoter was replaced with constitutively active promoters. Our results show that positive autoregulation ofbvgAStranscription is required for the temporal expression of multiple phenotypic phases that occurs in response to a shift from Bvg−-phase conditions to Bvg+-phase conditions. Autoregulation was also shown to contribute to steady-state regulation; it influences the sensitivity of the system in response to subtle differences in signal intensity. In addition, considered in relation to BvgA and BvgS activities demonstrated in vitro, our results provide insight into how BvgA and BvgS function mechanistically.
ArylamineN-Acetyltransferase Responsible for Acetylation of 2-Aminophenols inStreptomyces griseus
Authors: Suzuki Hirokazu , Ohnishi Yasuo , Horinouchi Sueharu
Published: December 2006

An arylamineN-acetyltransferase (NAT) responsible for the N acetylation of exogenous 3-amino-4-hydroxybenzoic acid inStreptomyces griseuswas identified and characterized. This enzyme was distinct from other eukaryotic and bacterial NATs in that it acetylated various 2-aminophenol derivatives more effectively than it acetylated 5-aminosalicylic acid, and thus it may be involved in the metabolism of xenobiotic compounds.
Tissue factor expression by a human kidney proximal tubular cell line in vitro: a model relevant to urinary tissue factor secretion in disease?
Authors: Lwaleed Bashir A , Vayro Steven , Racusen Lorraine C , Cooper Alan J
Published: December 2006

Aim:To study baseline and stimulated tissue factor (TF) production from a normal, albeit immortalised, human kidney proximal tubular cell line (HKC-5), in order to establish a model for investigating the role of inflammatory mediators in the increased urinary TF (uTF) seen in inflammatory and neoplastic disease.

Methods:TF procoagulant activity, expression and secretion in HKC-5 cells were investigated using TF activity and antigen assays, fluorescence confocal microscopy and immunocytochemistry. TF expression in the HKC-5 cells was also studied using reverse transcription (RT)-PCR and its synthesis was suppressed using antisense oligodeoxynucleotide (ODN), directed against human TF mRNA. Cells were stimulated, after serum deprivation, with bacterial lipopolysaccharide (LPS), an agonist known to enhance TF expression in monocytes. They were also subject to serum starvation.

Results:Analysis by RT-PCR showed TF production by stimulated and actively metabolising HKC-5 cells. Antisense ODN treatment resulted in approximately 50% suppression of TF synthesis compared to a mismatch ODN. The amount of TF produced by the HKC-5 cells was time dependent and coincides with a decrease in the intracellular TF levels. LPS up-regulated TF production in HKC-5 cells. Reducing fetal calf serum concentrations in the culture medium decreased TF production and secretion.

Conclusion:Stimulated TF synthesis and secretion in vitro by HKC-5 cells is consistent with the hypothesis that uTF is produced by tubular cells influenced by mediators of disease states and provides a model for further mechanistic investigations.
Hodgkin’s lymphoma associated T-cells exhibit a transcription factor profile consistent with distinct lymphoid compartments
Authors: Atayar Çiğdem , van den Berg Anke , Blokzijl Tjasso , Boot Marcel , Gascoyne Randy D , Visser Lydia , Poppema Sibrand
Published: December 2006

Background:

Hodgkin’s lymphoma (HL) is characterised by an ineffective immune response that is predominantly mediated by CD4+T-cells.

Aims:

To analyse the expression of the key regulatory T-cell transcription factors (TFs) in the T-cells of HL involved tissues in order to assess the nature of the THimmune response in HL.

Methods and results:

By immunohistochemistry, GATA3 was strongly and T-bet exclusively expressed in a subset of interfollicular lymphocytes in the reactive lymphoid tissues. In classical HL (CHL), which is generally located in the interfollicular zones, a predominance of T-bet+T-cells and lesser amounts of GATA3+and c-Maf+T-cells was found, concordant with the pattern of the normal interfollicular compartment. In reactive lymphoid tissues, c-Maf was observed mostly in T-lymphocytes within the germinal centres (GCs). Nodular lymphocyte predominance type of Hodgkin’s lymphoma (NLPHL) and progressively transformed germinal centres cases, showed a majority of c-Maf+T-cells, consistent with the pattern in normal GCs. NLPHL cases uniformly showed c-Maf+/CD57+T-cell rosettes around the neoplastic cells; these rosettes were absent in “paragranuloma-type” T-cell/histiocyte rich B-cell lymphoma.

Conclusions:

T-cell TF expression profiles of the reactive T-cells in both subtypes of HL are in accordance with the expression profile observed in the distinct lymphoid compartments.
Naturally-occurring regulatory T cells are increased in inflamed portal tracts with cholangiopathy in primary biliary cirrhosis
Authors: Sasaki Motoko , Ikeda Hiroko , Sawada Seiko , Sato Yasunori , Nakanuma Yasuni
Published: December 2006

Background:

Primary biliary cirrhosis (PBC) is an autoimmune liver disease targeting the intrahepatic small bile ducts showing chronic non-suppurative destructive cholangitis (CNSDC). Recent studies suggest that naturally-occurring CD4+CD25highregulatory T cells (Tregs) expressing Forkhead box P3 (Foxp3) play an active role in immunological self-tolerance.

Aims:

To investigate whether Foxp3+Tregs are involved in the pathogenesis of PBC.

Methods:

Foxp3+Tregs was detected immunohistochemically in livers from patients with PBC (n = 27), chronic viral hepatitis (CVH) (n = 15), and normal subjects (n = 10). The distribution of Tregs in portal tracts was semi-quantitatively evaluated in each groups. Levels of Foxp3, IL-10, TGFβ, IFNγ and TNFα mRNA was evaluated in PBC (n = 15) and control livers (n = 21) using semi-quantitative reverse transcriptase-PCR.

Results:

In PBC and CVH livers, the amounts of infiltrating Foxp3+Tregs in portal tracts were in parallel with the degree of portal inflammation irrespective of disease. The infiltration of Foxp3+Tregs into portal tracts with CNSDC in PBC was foremost in comparison with inflamed portal tracts in CVH or those without CNSDC in PBC (p<0.05). Focally, Tregs infiltrated into the biliary epithelial layer at the site of CNSDC. The level of Foxp3, IL-10 and TGFβ mRNA expression was high in PBC compared with normal livers (p<0.05). IFNγ and TNFα mRNA was high in early PBC and CVH livers.

Conclusion:

Results of this evaluation of Foxp3+Tregs do not suggest that the reduced regulatory function accounts for the development of CNSDC in PBC.
Symptom Combinations Associated with Outcome and Therapeutic Effects in a Cohort of Cases with SARS
Authors: Li Shao , Wang Ruiqin , Zhang Yulong , Zhang Xuegong , Layon A. Joseph , Li Yanda , Chen Mingzhe
Published: December 2006

Severe acute respiratory syndrome (SARS) is an infectious disease and some of its symptoms were clinically indistinguishable of those from similar diseases. This study aimed to find the symptom combinations associated with adverse outcome and the therapeutic effects in a cohort of patients with probable SARS retrospectively. In 2003, 123 SARS cases in Beijing were subjected to a strictly western medicine (WM) treatment, or a combined treatment (WM plus Herba houttuyniae injection, addition of individualized herbal treatments when necessary), of which 115 were followed till death or discharge; 8 were transferred and lost to follow-up. In both treatment groups, clinical manifestations were evaluated daily; development of signs and symptoms, and their possible relationship with outcome, were assessed. The relationships between these sign/symptom complexes and outcome under two treatment protocols were evaluated and differences were noted. Dynamic symptom combinations, dividing into the early, the medium-term and the durational symptom clusters, were identified as likely being related to the adverse outcomes of SARS ( p < 0.05, p < 0.01). Compared with a strictly WM treatment, the combined treatment resulted in a longer hospital stay ( p = 0.028), a non-statistically significant mortality rate decrease (combined treatment: 9.6% versus WM: 11.1%), and a significant improvement of arthralgia and myalgia ( p < 0.05) in the early symptom cluster. Additionally, the combined protocol improved arterial oxyhemoglobin saturation significantly at day 22 ( p < 0.05). In conclusion, the progress and outcome of SARS may be associated with specific temporal patterns of development in combination of several non-specific signs and symptom complexes, which are also helpful for evaluating the therapeutic effects on SARS patients.
Qigong Exercise with Concentration Predicts Increased Health
Authors: Jouper John , Hassmén Peter , Johansson Mattias
Published: December 2006

Regular physical activity has many positive health effects. Despite this, approximately 50% of all adults are not exercising enough to enjoy better health and may, therefore, need an alternative to vigorous physical exercise. Qigong offers a gentle way to exercise the body. A questionnaire sample of 253 participants was collected and correlations with the variable health-now were analyzed. Results showed that health-now was positively correlated with number of completed qigong courses ( p < 0.05), with level of concentration ( p < 0.01), session-time ( p < 0.01), and years of practice ( p < 0.05). Among these variables, concentration predicts an increased feeling of health ( R 2 = 0.092). Qigong exercise thereby seems to offer a viable alternative to other more vigorous physical activities when wellness is the primary goal. When interpreted using self-determination theory, qigong seems to satisfy needs related to autonomy, competence and relatedness, thereby, primarily attracting individuals who are intrinsically motivated.
Comparison of the Effects of Tai Chi Chuan and Wai Tan Kung Exercises on Autonomic Nervous System Modulation and on Hemodynamics in Elder Adults
Authors: Lu Wan-An , Kuo Cheng-Deng
Published: December 2006

The health of the middle-aged and elderly people is a major concern given the rapid aging population and rising costs of medical care. Low-impact exercise on a regular basis is ideal for maintaining the well-being of an aging population. Tai Chi Chuan (TCC) is the most well-known and most widely practiced form of low-impact martial arts therapy and has been shown to have positive health effects. A lesser-known form of martial arts therapy is Wai Tan Kung (WTK), which our previous study found to have positive health effects as well. The present study compares the effects of TCC and WTK on autonomic nervous system modulation and on hemodynamics in adults among non-exercising control (30), TCC practitioners (30) and WTK practitioners (30). Our study found that in a short-term, WTK and TCC exercises enhanced the vagal modulation, lowered the sympathetic modulation and lowered arterial blood pressures in the practitioners. It was also observed that the forced vital capacity of TCC practitioners was significantly higher than that of WTK practitioners before exercise. There were no significant differences in the percentage changes in HRV measures and hemodynamics between WTK and TCC practitioners 30 and 60 min after exercise, indicating that the effects of WTK and TCC were similar in magnitude. In conclusion, TCC and WTK are comparable to each other in terms of their effects on autonomic nervous system modulation and hemodynamics, thus suggesting that WTK can be just as beneficial as TCC as a form of low-impact exercise for elderly adults.
Comparison of Effects of Vitamin E and Wen-jing-tang (Unkei-to), An Herbal Medicine, on Peripheral Blood Flow in Post-menopausal Women with Chilly Sensation in the Lower Extremities: A Randomized Prospective Study
Authors: Ushiroyama Takahisa , Sakuma Kou , Nosaka Sakura
Published: December 2006

We examined the association between blood flow and chilly sensation in the lower extremities, comparing the changes in blood flow induced by the vitamin E and herbal therapy (Wen-jing-tang) in perimenopausal women with chilly sensation. One hundred sixty-one perimenopausal women aged 42–61 years (mean: 50.4 ± 3.8 years) with chilly sensation in the lower extremities participated in the study. The participants were randomized for treatment with Wen-jing-tang or a vitamin E preparation containing 600 mg tocopherol nictinate per day for 8 weeks. Blood flow measurement was performed by laser Doppler fluxmetry to determine tissue under the jaw, in the middle finger, and in the third toe. Wen-jing-tang significantly increased the peripheral blood flow in the skin surface in the tiptoe (12.8 ± 8.8, p = 0.0068) from basal levels (6.0 ± 5.1), although no significant change was observed in the blood flow in fingertip or under the jaw during treatment. The rate of increase of blood flow in the skin surface of in the lower extremities was significantly higher in the Wen-jing-tang treating group (116.4 ± 46.5%) than in the vitamin E group (39.8 ± 21.3%)( p < 0.0001). When the effects of herbal treatment and vitamin E treatment were compared in the subjects with baseline upper extremity blood flow above the mean + 1.5 SD, mean blood flow through the upper extremities was found to have been significantly decreased after Wen-jing-tang treatment (from 57.7 ± 4.8 to 43.1 ± 4.2, p = 0.0277), whereas it remained unchanged after treatment with vitamin E.

Classical monographs described Wen-jing-tang as being particularly useful in curing chilly sensation in lower extremities. The present study using a laser Doppler fluxmeter demonstrated that treatment with this herbal medicine significantly increased blood flow through the periphery of lower extremities in patients with chilly sensation. It also showed that this herbal medicine suppresses excessive blood flow through the upper half of the body and thus stimulates restoration of physiological distribution of blood flow throughout the entire body.
The Effect of EA on the Gastric Mucosal Histology and ITF mRNA Expression in Stress-Induced Rats
Authors: Li Xi-Ping , Yan Jie , Yi Shou-Xiang , Chang Xiao-Rong , Lin Ya-Ping , Huang Ai , Hu Rong
Published: December 2006

This study focuses on the effect of electroacupuncture (EA) on the gastric mucosal histology and ITF (intestinal trefoil factor) mRNA in stress-related rat, and the relationship between the gastric protective mechanism of EA at acupoints of Stomach Meridian of Foot-Yangming (SMFY) group and Gallbladder Meridian of Foot-Shaoyang (GMFS) group. Forty rats were randomly divided into 4 groups: blank control group (BCG), model control group (MCG), SMFY group (EA at acupoints of SMFY for 7 days before model inducing), and GMFS group (EA at acupoints of GMFS for 7 days before model inducing). All rats (except normal group) were made model by water immersion and restriction (WRS) on day 7, then the gastric mucosal lesion index (GUI) was accessed, ITF mRNA expression of the tissue was detected by reverse- transcriptase-polymerase chain reaction (RT-PCR) method, and the histological change under light microscope was observed. As a result, the GUI value in SMFY/GMFS groups decreased significantly ( p < 0.05 or 0.01). The level of ITF mRNA expression in SMFY group was significantly higher than that in MCG ( p < 0.01), while that in GMFS group was higher than MCG but there was no statistical difference ( p < 0.05). This result may be due to the intrinsic mechanism of EA's gastric mucosal protection by the upregulation of ITF mRNA expression in gastric mucosal tissue, and the expression variance indicated the classical traditional Chinese medicine (TCM) theory "Relative Particularity between SMFY and Stomach.".
Gastroprotective Effect of Fructus Evodiae Water Extract on Ethanol-Induced Gastric Lesions in Rats
Authors: Yu Xiao , Wu Da-Zheng , Yuan Jian-Ye , Zhang Rong-Rong , Hu Zhi-Bi
Published: December 2006

Fructus Evodiae is a widely used herbal medicine with anti-inflammatory and analgetic activities in China. The present study was designed to investigate the effect of Fructus Evodiae water extract (FE) on ethanol-induced gastric lesions in rats. Three hours before ethanol challenge, animals were intraperitoneally treated with FE (424.8 mg/kg, 141.6 mg/kg, and 47.6 mg/kg). Subsequently, we employed ex-vivo chamber technique to examine the effect of FE on gastric transmucosal potential difference (PD) changes. NOx (nitrate and nitrite) in gastric perfusate and gastric lesion index of whole glandular stomach were determined by intubation. The results showed that FE dose-dependently accelerated the recovery of PD reduction by ethanol, and increased NOx production in gastric perfusate. FE also inhibited gastric lesion formation in a dose-dependent manner. These results suggested that FE prevented ethanol-induced gastric mucosal lesions by strengthening the mucosal barrier integrity and increasing gastric mucosal nitric oxide (NO) synthesis.