bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quorum Sensing Regulates Type III Secretion inVibrio harveyiandVibrio parahaemolyticus
Authors: Henke Jennifer M. , Bassler Bonnie L. 
Published: June 2004

ABSTRACTIn a process known as quorum sensing, bacteria communicate with one another by producing, releasing, detecting, and responding to signal molecules called autoinducers.Vibrio harveyi, a marine pathogen, uses two parallel quorum-sensing circuits, each consisting of an autoinducer-sensor pair, to control the expression of genes required for bioluminescence and a number of other target genes. Genetic screens designed to discover autoinducer-regulated targets inV. harveyihave revealed genes encoding components of a putative type III secretion (TTS) system. Using transcriptional reporter fusions and TTS protein localization studies, we show that the TTS system is indeed functional inV. harveyiand that expression of the genes encoding the secretion machinery requires an intact quorum-sensing signal transduction cascade. The newly completed genome of the closely related marine bacteriumVibrio parahaemolyticus, which is a human pathogen, shows that it possesses the genes encoding both of theV. harveyi-like quorum-sensing signaling circuits and that it also has a TTS system similar to that ofV. harveyi. We show that quorum sensing regulates TTS inV. parahaemolyticus. Previous reports connecting quorum sensing to TTS in enterohemorrhagic and enteropathogenicEscherichia colishow that quorum sensing activates TTS at high cell density. Surprisingly, we find that at high cell density (in the presence of autoinducers), quorum sensing represses TTS inV. harveyiandV. parahaemolyticus.
Detection and Characterization of Conjugative Degradative Plasmids in Xenobiotic-Degrading
Sphingomonas
Strains
Authors: Basta Tamara , Keck Andreas , Klein Joachim , Stolz Andreas 
Published: June 2004

ABSTRACT

A systematic survey for the presence of plasmids in 17 different xenobiotic-degrading
Sphingomonas
strains was performed. In almost all analyzed strains, two to five plasmids with sizes of about 50 to 500 kb were detected by using pulsed-field gel electrophoresis. A comparison of plasmid preparations untreated or treated with S1 nuclease suggested that, in general,
Sphingomonas
plasmids are circular. Hybridization experiments with labeled gene probes suggested that large plasmids are involved in the degradation of dibenzo-
p
-dioxin, dibenzofuran, and naphthalenesulfonates in
S. wittichii
RW1,
Sphingomonas
sp. HH69, and
S. xenophaga
BN6, respectively. The plasmids which are responsible for the degradation of naphthalene, biphenyl, and toluene by
S. aromaticivorans
F199 (pNL1) and of naphthalenesulfonates by
S. xenophaga
BN6 (pBN6) were site-specifically labeled with a kanamycin resistance cassette. The conjugative transfer of these labeled plasmids was attempted with various bacterial strains as putative recipient strains. Thus, a conjugative transfer of plasmid pBN6 from
S. xenophaga
BN6 to a cured mutant of strain BN6 and to
Sphingomonas
sp. SS3 was observed. The conjugation experiments with plasmid pNL1 suggested a broader host range of this plasmid, because it was transferred without any obvious structural changes to
S. yanoikuyae
B1,
Sphingomonas
sp. SS3, and
S. herbicidovorans
. In contrast, major plasmid rearrangements were observed in the transconjugants after the transfer of plasmid pNL1 to
Sphingomonas
sp. HH69 and of pBN6 to
Sphingomonas
sp. SS3. No indications for the transfer of a
Sphingomonas
plasmid to bacteria outside of the
Sphingomonadaceae
were obtained.
Role of the Anti-Sigma Factor SpoIIAB in Regulation of σ
G
during
Bacillus subtilis
Sporulation
Authors: Serrano Mónica , Neves Alexandre , Soares Cláudio M. , Moran Charles P. , Henriques Adriano O. 
Published: June 2004

ABSTRACT

RNA polymerase sigma factor σ
F
initiates the prespore-specific program of gene expression during
Bacillus subtilis
sporulation. σ
F
governs transcription of
spoIIIG
, encoding the late prespore-specific regulator σ
G
. However, transcription of
spoIIIG
is delayed relative to other genes under the control of σ
F
, and after synthesis, σ
G
is initially kept in an inactive form. Activation of σ
G
requires the complete engulfment of the prespore by the mother cell and expression of the
spoIIIA
and
spoIIIJ
loci. We screened for random mutations in
spoIIIG
that bypassed the requirement for
spoIIIA
for the activation of σ
G
. We found a mutation (
spoIIIGE156K
) that resulted in an amino acid substitution at position 156, which is adjacent to the position of a mutation (E155K) previously shown to prevent interaction of SpoIIAB with σ
G
. Comparative modelling techniques and in vivo studies suggested that the
spoIIIGE156K
mutation interferes with the interaction of SpoIIAB with σ
G
. The σ
GE156K
isoform restored σ
G
-directed gene expression to
spoIIIA
mutant cells. However, expression of
sspE
-
lacZ
in the
spoIIIA spoIIIGE156K
double mutant was delayed relative to completion of the engulfment process and was not confined to the prespore. Rather, β-galactosidase accumulated throughout the entire cell at late times in development. This suggests that the activity of σ
GE156K
is still regulated in the prespore of a
spoIIIA
mutant, but not by SpoIIAB. In agreement with this suggestion, we also found that expression of
spoIIIGE156K
from the promoter for the early prespore-specific gene
spoIIQ
still resulted in
sspE-lacZ
induction at the normal time during sporulation, coincidently with completion of the engulfment process. In contrast, transcription of
spoIIIGE156K
, but not of the wild-type
spoIIIG
gene, from the mother cell-specific
spoIID
promoter permitted the rapid induction of
sspE-lacZ
expression. Together, the results suggest that SpoIIAB is either redundant or has no role in the regulation of σ
G
in the prespore.
The Last Gene of the
fla/che
Operon in
Bacillus subtilis
,
ylxL
, Is Required for Maximal σ
D
Function
Authors: Werhane H. , Lopez P. , Mendel M. , Zimmer M. , Ordal G. W. , Márquez-Magaña L. M. 
Published: June 2004

ABSTRACT

ylxL
was found to be the last gene of the
fla/che
operon in
Bacillus subtilis
and is cotranscribed with the gene for the flagellum-specific alternate sigma factor, σ
D
. The
ylxL
gene was disrupted by insertional mutagenesis, and the resultant mutant strain was found to be compromised for σ
D
-dependent functions.
The Acidic Nature of the CcmG Redox-Active Center Is Important for CytochromecMaturation inEscherichia coli
Authors: Edeling Melissa A. , Ahuja Umesh , Heras Begoña , Thöny-Meyer Linda , Martin Jennifer L. 
Published: June 2004

ABSTRACTCytochromecbiogenesis inEscherichia coliis a complex process requiring at least eight genes (ccmABCDEFGH). One of these genes,ccmG, encodes a thioredoxin-like protein with unusually specific redox activity. Here, we investigate the basis for CcmG function and demonstrate the importance of acidic residues surrounding the redox-active center.
A Mutant Allele of
rpoD
Results in Increased Conversion of Aminoimidazole Ribotide to Hydroxymethyl Pyrimidine in
Salmonella enterica
Authors: Dougherty Michael J. , Downs Diana M. 
Published: June 2004

ABSTRACT

An allele of
rpoD
(
rpoD1181
) that results in increased synthesis of the pyrimidine moiety of thiamine in
Salmonella enterica
was identified. The S508Y substitution caused by
rpoD1181
is analogous to the S506F derivative of the
Escherichia coli
protein. The properties of this
E
.
coli
mutant protein have been well characterized in vitro. Identification of a metabolic phenotype caused by the
rpoD1181
allele of
S
.
enterica
allows past in vitro results to be incorporated in continuing efforts to understand cellular processes that are integrated with the thiamine biosynthetic pathway.
Antitussive Profile of the NOP Agonist Ro-64-6198 in the Guinea Pig
Authors: McLeod Robbie L. , Jia Yanlin , Fernandez Xiomara , Parra Leonard E. , Wang Xin , Tulshian Deen B. , Kiselgof Eugenia J. , Tan Zheng , Fawzi Ahmad B. , Smith-Torhan April , Zhang Hongtao , Hey John A. 
Published: May 2004

We have previously shown that N/OFQ, the endogenous peptide ligand for the ‘opioid-like’ NOP receptor, inhibits cough in guinea pigs and cats. In the present study we sought to continue our characterization of the cough-suppressant effects of NOP stimulation by profiling the pulmonary and antitussive effects of a novel non-peptide NOP agonist, Ro-64-6198, in guinea pigs. In receptor-binding assays, we confirmed that Ro-64-6198 selectively binds to NOP receptors over other opioid receptors. The K<sub>i</sub> values for Ro-64-6198 at NOP, MOP, KOP and DOP receptors was 0.3, 36, 214 and 3,787 nmol/l, respectively. In GTPγS-binding assays, Ro-64-6198 displayed >900-fold functional selectivity at NOP relative to MOP receptors. We evaluated the effects of Ro-64-6198 (3 and 10 µmol/l) in isolated guinea pig nodose ganglia cells on the increases in intracellular Ca<sup>2+</sup> concentration evoked by capsaicin stimulation (1 × 10<sup>–8</sup>–1 × 10<sup>–6</sup> mol/l). Similar to previously reported data with N/OFQ, Ro-64-6198 (3 and 10 µmol/l) significantly attenuated Ca<sup>2+</sup> responses in nodose ganglia cells produced by exposure to capsaicin. The effect of Ro-64-6198 (3 µmol/l) on capsaicin-induced intracellular Ca<sup>2+</sup> responses was blocked by the NOP antagonist, J113397 (3 µmol/l). In guinea pig in vivo studies, aerosolized capsaicin (10–300 µmol/l) produced a dose-dependent increase in cough number. Ro-64-6198 given i.p. significantly inhibited cough due to capsaicin (300 µmol/l) exposure. In a duration study we found that the maximum antitussive effect (42 ± 8% inhibition) of Ro-64-6198 (3 mg/kg) was observed at 1 h after i.p. administration. Also at 1 h after administration, Ro-64-6198 (0.003–3.0 mg/kg, i.p.) produced a dose-dependent inhibition of cough. The antitussive effect of Ro-64-6198 (3 mg/kg, i.p.) was blocked by J113397 (12 mg/kg, i.p.) but not by the classical opioid antagonist naltrexone (10 mg/kg, i.p.). Although the antitussive action of Ro-64-6198 may be mediated by a central and/or a peripheral site of action, we hypothesize that selective oral NOP agonists that do not penetrate the blood-brain barrier may provide a novel approach for the treatment of cough. Moreover, because these drugs do not interact at MOP receptors, they may be devoid of codeine-like side effects such as respiratory depression, sedation, constipation or proclivities for addictive liabilities.
Comparative Effects of Quinapril with Enalapril in Rats with Heart Failure
Authors: Watanabe Kenichi , Ma Meilei , Wen Juan , Tachikawa Hitoshi , Kodama Makoto , Aizawa Yoshifusa , Yamaguchi Kenichi , Takahashi Toshihiro 
Published: May 2004

The cardioprotective properties of angiotensin-converting enzyme (ACE) inhibitors, quinapril and enalapril were studied in a rat model of heart failure. Seventy-five rats were divided into five groups and administered quinapril or enalapril at 2 and 20 mg/kg/day (groups Q2, Q20, E2 and E20) or vehicle alone (group V, all groups n = 15). Although both ACE inhibitors improved survival rate and ventricular function in a dose-dependent manner, the left ventricular end-diastolic pressure and expression level of transforming growth factor-β<sub>1</sub> mRNA were the lowest in group Q20. These results suggest that quinapril may confer greater protection than enalapril against injury from the renin-angiotensin system in heart failure.
Repair rates of R-band, G-band and C-band DNA in murine and human cultured cells
Authors: Sanders M.H. , Bates S.E. , Wilbur B.S. , Holmquist G.P. 
Published: May 2004

Repair of cyclobutane pyrimidine dimers (CPDs) in cultured neonatal human fibroblasts and in <i>Mus spretus × M. castaneus</i> F<sub>1</sub> neonatal skin fibroblasts was analyzed after UVC-irradiation by cleavage with T4 endonuclease V cyclopyrimidine dimer glycosylase, alkaline-agarose gel electrophoresis, and Southern blotting. The blots were sequentially probed with <sup>32</sup>P-labeled Alu, or B2, to preferentially illuminate R-band DNA, by L1 to preferentially illuminate G-band DNA, and by satellite DNA to illuminate C-band DNA. These three different DNA populations showed slightly different global nucleotide excision repair rates that are in the order of speed, R-band DNA > G-band DNA > C-band DNA. Fibroblasts from out-bred neonatal mice and humans showed similar band-specific repair rate ratios and the global repair rate of murine fibroblasts was almost as rapid as that of the human fibroblasts. The mass distribution of the human Alu-probed signal was further analyzed. Gel mobility data was fitted to a logistic equation to include all M<sub>r</sub> values. Hypothetical distributions of DNA randomly cleaved to a particular number-average molecular weight were fit to the logistic gel mobility function to determine how such a randomly cleaved distribution of a particular cleavage frequency would be displayed along the experimental gel. This revealed a rapidly repaired kinetic fraction that represented 17% of the Alu-probed signal (R-band DNA), almost none of the L1 probed signal (G-band DNA), and reflects transcription coupled repair of active genes. The remaining Alu-probed DNA showed a random distribution of UVC-induced CPDs throughout all stages of global nucleotide excision repair. The Alu-probed CPDs disappeared with an excellent fit to first order kinetics and with a half-life of seven hours.
Cytogenetic analyses in peripheral lymphocytes of persons living in houses with increased levels of indoor radon concentrations
Authors: Oestreicher U. , Braselmann H. , Stephan G. 
Published: May 2004

Published data concerning the effects of indoor radon exposure on the frequency of chromosome aberrations in peripheral lymphocytes of residents are contradictory. Possible reasons for this may be the low radon concentration in dwellings and/or the limited number of investigated persons. We therefore studied the relationship of domestic radon exposure and the occurrence of chromosome aberrations in peripheral lymphocytes in 61 persons living in houses with radon concentrations from 80 up to 13,000 Bq/m<sup>3</sup>. We analyzed 60,000 cells from fluorescence plus Giemsa (FPG)-stained slides. It could be clearly demonstrated that in groups of persons living in dwellings with indoor radon concentrations >200 Bq/m<sup>3</sup> the number of cells containing dicentrics and/or centric rings (C<sub>dic + cr</sub>) (2.45 ± 0.50 × 10<sup>–3</sup>) was significantly increased (<i>p</i> < 0.05) in comparison to the control level (1.03 ± 0.15 × 10<sup>–3</sup>). However, there was no difference in the mean frequency of C<sub>dic + cr</sub> between the groups living in dwellings with higher radon concentrations. Using the fluorescence in situ hybridization (FISH) technique for the detection of translocations, we analyzed 23,315 cells in 16 persons of the highest exposed group (>5,000 Bq/m<sup>3</sup>). The observed frequency of translocations was 3.9 ± 0.64 × 10<sup>–3</sup>. In comparison to the control group (2.02 ± 0.18 × 10<sup>–3</sup>), there was a slight but not statistically significant increase in the exposed group (<i>P</i> = 0.055). If, however, the age of the examined persons is taken into account, the values are significantly increased (<i>P</i> < 0.05) in the exposed persons older than 40 years in comparison to the age-matched controls. Since most of the translocations were found in stable cells, it is concluded that translocations are also induced in blood-forming tissue and are transmitted to peripheral blood.
High Intensity Exercise Enhances Platelet Reactivity to Shear Stress and Coagulation during and after Exercise
Authors: Ikarugi Hideo , Shibata Masashi , Shibata Shiori , Ishii Hiromitsu , Taka Tomomi , Yamamoto Junichiro 
Published: May 2004

Platelets play a crucial role in the pathogenesis of acute cardiac events, such as angina, myocardial infarction and sudden death. It is believed that regular low-intensity exercise can reduce, while high-intensity exercise may provoke acute cardiac events. The aim of the present study was to investigate the effect of acute exercise both at low and high intensities on the ventilatory threshold (VT), platelet reactivity and coagulation before and after exercise. Platelet reactivity and coagulation were measured under flow condition, using native blood, by hemostatometry. Seven healthy young men (age: 20–29 years) performed bicycle ergometer exercise for 30 min at intensities of 90% (Ex-VT90% or approximately 55% VO<sub>2max</sub>) and 130% (Ex-VT130% or 80% VO<sub>2max</sub>) of individual VT. Blood cell counts, hematocrit, blood lactic acid and plasma catecholamine levels were slightly but significantly increased after Ex-VT90% and markedly after Ex-VT130% after 30 min exercise. Subsequent to the exercise, the elevated blood cell counts decreased to the resting levels both at Ex-VT90% and at Ex-VT130%. Platelet reactivity to shear stress and dynamic coagulation were significantly enhanced immediately and 30 min after Ex-130%VT. In contrast, no significant changes occurred in those of Ex-90%VT. The present study suggests that high-intensity exercise-induced platelet hyperreactivity and hypercoagulable state may pose an increased risk for acute, sometimes fatal cardiac event. On the other hand, our findings support the view that low-intensity exercise does not present a risk of thrombosis.
Effects of volume resuscitation on splanchnic perfusion in canine model of severe sepsis induced by live Escherichia coli infusion
Authors: Lagoa Claudio Esteves , de Figueiredo Luiz FranciscoPoli , Cruz Ruy Jorge , Silva Eliézer , Rocha e Silva Maurício 
Published: May 2004

Abstract
Introduction
We conducted the present study to investigate whether early large-volume crystalloid infusion can restore gut mucosal blood flow and mesenteric oxygen metabolism in severe sepsis.

Methods
Anesthetized and mechanically ventilated male mongrel dogs were challenged with intravenous injection of live Escherichia coli (6 × 109 colony-forming units/ml per kg over 15 min). After 90 min they were randomly assigned to one of two groups – control (no fluids; n = 13) or lactated Ringer's solution (32 ml/kg per hour; n = 14) – and followed for 60 min. Cardiac index, mesenteric blood flow, mean arterial pressure, systemic and mesenteric oxygen-derived variables, blood lactate and gastric carbon dioxide tension (PCO2; by gas tonometry) were assessed throughout the study.

Results
E. coli infusion significantly decreased arterial pressure, cardiac index, mesenteric blood flow, and systemic and mesenteric oxygen delivery, and increased arterial and portal lactate, intramucosal PCO2, PCO2 gap (the difference between gastric mucosal and arterial PCO2), and systemic and mesenteric oxygen extraction ratio in both groups. The Ringer's solution group had significantly higher cardiac index and systemic oxygen delivery, and lower oxygen extraction ratio and PCO2 gap at 165 min as compared with control animals. However, infusion of lactated Ringer's solution was unable to restore the PCO2 gap. There were no significant differences between groups in mesenteric oxygen delivery, oxygen extraction ratio, or portal lactate at the end of study.

Conclusion
Significant disturbances occur in the systemic and mesenteric beds during bacteremic severe sepsis. Although large-volume infusion of lactated Ringer's solution restored systemic hemodynamic parameters, it was unable to correct gut mucosal PCO2 gap.
Accidental catheter removal in critically ill patients: a prospective and observational study
Authors: Lorente Leonardo , Huidobro María S , Martín María M , Jiménez Alejandro , Mora María L 
Published: June 2004

Abstract
Introduction
The importance of accidental catheter removal (ACR) lies in the complications caused by the removal itself and by catheter reinsertion. To the best of our knowledge, no studies have analyzed accidental removal of various types of catheters in the intensive care unit (ICU). The objective of the present study was to analyze the incidence of ACR for all types of catheters in the ICU.

Methods
This was a prospective and observational study, conducted in a 24-bed medical/surgical ICU in a university hospital. We included all consecutive patients admitted to the ICU over 18 months (1 May 2000 to 31 October 2001). The incidences of ACR for all types of catheters (both per 100 catheters and per 100 catheter-days) were determined.

Results
A total of 988 patients were included. There were no significant differences in ACR incidence between the four central venous access sites (peripheral, jugular, subclavian and femoral) or between the four arterial access sites (radial, femoral, pedal and humeral). However, the incidence of ACR was higher for arterial than for central venous catheters (1.12/100 catheter-days versus 2.02/100 catheter-days; P < 0.001). The incidences of ACR/100 nonvascular catheter-days were as follows: endotracheal tube 0.79; nasogastric tube 4.48; urinary catheter 0.32; thoracic drain 0.56; abdominal drain 0.67; and intraventricular brain drain 0.66.

Conclusion
We found ACR incidences for central venous catheter, arterial catheter, endotracheal tube, nasogastric tube and urinary catheter that are similar to those reported in previous studies. We could not find studies that analyzed the ACR for thoracic, abdominal, intraventricular brain and cardiac surgical drains, but we believe that our rates are acceptable. To minimize ACR, it is necessary to monitor its incidence carefully and to implement preventive measures. In our view, according to establish quality standards, findings should be reported as ACR incidence per 100 catheters and per 100 catheter-days, for all types of catheters.
A Calibrated Paper Clip Is a Reliable Measure of Two‐point Discrimination
Authors: Finnell John T. , Knopp Robert , Johnson Phelps , Holland Patrick C. , Schubert Warren 
Published: June 2004

Abstract Objectives: The primary objective of this study was to compare two different instruments for assessing digital nerve function; a secondary aim was to determine interobserver agreement among emergency physicians by using static two‐point testing of digital nerve function. Methods:This was a prospective, blinded, observational study of static two‐point discrimination involving healthy volunteers aged 18–59 years. The authors compared two instruments (paper clip set or Disk‐Criminator) to assess two‐point discrimination of the index and long fingers of the dominant hand. For each subject, the initial investigator and initial testing instrument were randomized. Two‐point testing was conducted at 4, 5, and 6 mm by using six randomly selected stimuli (1 or 2 points) for each distal phalanx tested. The study was designed to detect a 25% difference in mean two‐point distance with a power of 80%. Results: Seventy‐five subjects were entered into the study, of which two were excluded. Interinstrument agreement for a given investigator ranged from 77% to 84% for absolute agreement and 98% to 100% within 2 mm. Weighted kappa values for interobserver differences of 2 mm or less was 0.79 to 1.00. There was no statistically significant difference between instruments. Conclusions: Using a clinically relevant threshold of 2 mm, the authors found that a properly calibrated set of paper clips performed as well as the Disk‐Criminator.