bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the 5‐hydroxytryptamine receptors mediating contraction in the pig isolated intravesical ureter
Authors: Hernández Medardo , Barahona María Victoria , Simonsen Ulf , Recio Paz , Rivera Luis , Martínez Ana Cristina , García‐Sacristán Albino , Orensanz Luis M , Prieto Dolores 
Published: January 2003

This study was designed to investigate the effect of 5‐hydroxytryptamine (5‐HT) and to characterize the 5‐HT receptors involved in 5‐HT responses in the pig intravesical ureter.
5‐HT (0.01–10 μM) concentration‐dependently increased the tone of intravesical ureteral strips, whereas the increases in phasic contractions were concentration‐independent. The 5‐HT2 receptor agonist α‐methyl 5‐HT, mimicked the effect on tone whereas weak or no response was obtained with 5‐CT, 8‐OH‐DPAT, m‐chlorophenylbiguanide and RS 67333, 5‐HT1, 5‐HT1A, 5‐HT3 and 5‐HT4 receptor agonists, respectively. 5‐HT did not induce relaxation of U46619‐contracted ureteral preparations. Pargyline (100 μM), a monoaminooxidase A/B activity inhibitor, produced leftward displacements of the concentration‐response curves for 5‐HT.
5‐HT‐induced tone was reduced by the 5‐HT2 and 5‐HT2A receptor antagonists ritanserine (0.1 μM) and spiperone (0.2 μM), respectively. However, 5‐HT contraction was not antagonized by cyanopindolol (2 μM), SDZ–SER 082 (1 μM), Y‐25130 (1 μM) and GR 113808 (0.1 μM), which are respectively, 5‐HT1A/1B, 5‐HT2B/2C, 5‐HT3, and 5‐HT4 selective receptor antagonists.
Removal of the urothelium did not modify 5‐HT‐induced contractions. Blockade of neuronal voltage‐activated sodium channels, α‐adrenergic receptors and adrenergic neurotransmission with tetrodotoxin (1 μM), phentolamine (0.3 μM) and guanethidine (10 μM), respectively, reduced the contractions to 5‐HT. However, physostigmine (1 μM), atropine (0.1 μM) and suramin (30 μM), inhibitors of cholinesterase activity, muscarinic‐ and purinergic P2‐receptors, respectively, failed to modify the contractions to 5‐HT.
These results suggest that 5‐HT increases the tone of the pig intravesical ureter through 5‐HT2A receptors located at the smooth muscle. Part of the 5‐HT contraction is indirectly mediated via noradrenaline release from sympathetic nerves.

British Journal of Pharmacology (2003) 138, 137–144. doi:10.1038/sj.bjp.0705019
Involvement of tachykinin receptors in Clostridium perfringens beta‐toxin‐induced plasma extravasation
Authors: Nagahama Masahiro , Morimitsu Shinsuke , Kihara Atsushi , Akita Masahiko , Setsu Koujun , Sakurai Jun 
Published: January 2003

Clostridium perfringens beta‐toxin causes dermonecrosis and oedema in the dorsal skin of animals. In the present study, we investigated the mechanisms of oedema induced by the toxin.
The toxin induced plasma extravasation in the dorsal skin of Balb/c mice.
The extravasation was significantly inhibited by diphenhydramine, a histamine 1 receptor antagonist. However, the toxin did not cause the release of histamine from mouse mastocytoma cells.
Tachykinin NK1 receptor antagonists, [D‐Pro2, D‐Trp7,9]‐SP, [D‐Pro4, D‐Trp7,9]‐SP and spantide, inhibited the toxin‐induced leakage in a dose‐dependent manner. Furthermore, the non‐peptide tachykinin NK1 receptor antagonist, SR140333, markedly inhibited the toxin‐induced leakage.
The leakage induced by the toxin was markedly reduced in capsaicin‐pretreated mouse skin but the leakage was not affected by systemic pretreatment with a calcitonin gene‐related peptide receptor antagonist (CGRP8‐37).
The toxin‐induced leakage was significantly inhibited by the N‐type Ca2+ channel blocker, ω‐conotoxin MVIIA, and the bradykinin B2 receptor antagonist, HOE140 (D‐Arg‐[Hyp3, Thi5, D‐Tic7, Oic8]‐bradykinin), but was not affected by the selective L‐type Ca2+ channel blocker, verapamil, the P‐type Ca2+ channel blocker, ω‐agatoxin IVA, tetrodotoxin (TTX), the TTX‐resistant Na+ channel blocker, carbamazepine, or the sensory nerve conduction blocker, lignocaine.
These results suggest that plasma extravasation induced by beta‐toxin in mouse skin is mediated via a mechanism involving tachykinin NK1 receptors.

British Journal of Pharmacology (2003) 138, 23–30. doi:10.1038/sj.bjp.0705022
Modulation of steady‐state kinetics of digoxin by haplotypes of the P‐glycoprotein MDR1 gene
Authors: Johne Andreas , Köpke Karla , Gerloff Thomas , Mai Ingrid , Rietbrock Stephan , Meisel Christian , Hoffmeyer Sven , Kerb Reinhold , Fromm Martin F. , Brinkmann Ulrich , Eichelbaum Michel , Brockmöller Jürgen , Cascorbi Ingolf , Roots Ivar 
Published: January 2003

ObjectiveWe investigated the effect of polymorphisms in the P‐glycoprotein (P‐gp) MDR1 gene on steady‐state pharmacokinetics of digoxin in Caucasians. According to earlier data, homozygous TT of the exon 26 complementary deoxyribonucleic acid (cDNA) 3435C>T polymorphism was associated with low P‐gp expression in the human intestine.MethodsEight healthy male homozygous carriers of the wild‐type exon‐26 3435C>T (CC), 8 heterozygous subjects (CT), and 8 homozygous mutant (TT) subjects were selected. Seven further MDR1 polymorphisms were determined. Digoxin was administered orally twice daily on the first two study days; on days 3 to 5, 0.25 mg was given in the morning. On day 5, kinetic parameters were analyzed for genotype‐phenotype and haplotype‐phenotype relationships.ResultsThe area under the plasma concentration‐time curve from time zero to 4 hours [AUC(0–4)] (P = .042) and Cmax (P = .043) values of digoxin were higher in subjects with the 3435TT genotype than in those with the 3435CC. No influence of other single nucleotide polymorphisms (SNPs) on digoxin parameters was detected. Comparison of genotypes deduced from SNPs 2677G>T (exon 21) and 3435C>T revealed significant differences for AUC(0–4) (P = .034) and Cmax (P = .039), which were substantiated by haplotype analysis. Haplotype 12 (2677G/3435T), which had a frequency of 13.3% in a randomly drawn Caucasian sample (n = 687), was associated (Mann‐Whitney test) with higher AUC(0–4) values (P = .009) than were found in noncarriers (mean ± SD, 5.7 ± 0.9 μg · h/L [n = 7] versus 4.8 ± 0.9 μg · h/L [n = 17]). Haplotype 11 (2677G/3435C) had lower AUC(0–4) values (P = .013) compared with those of noncarriers (mean ± SD, 4.7 ± 0.9 μg · h/L [n = 16] versus 5.6 ± 0.9 μg · h/L [n = 8]). Results of haplotype analysis match data of other MDR1 studies.ConclusionHaplotype 12 codes for high values of AUC(0–4) and Cmax of orally administered digoxin. Analysis of MDR1 haplotypes is superior to unphased SNP analysis to predict MDR1 phenotype.Clinical Pharmacology & Therapeutics (2002) 72, 584–594; doi: 10.1067/mcp.2002.129196
Development and Application of Different Methods for the Detection of
Toxoplasma gondii
in Water
Authors: Kourenti Christina , Heckeroth Anja , Tenter Astrid , Karanis Panagiotis 
Published: January 2003

ABSTRACT

Two methods, centrifugation and flocculation, were evaluated to determine their efficiencies of recovery of
Toxoplasma gondii
oocysts from contaminated water samples. Demineralized and tap water replicates were inoculated with high numbers of sporulated or unsporulated
T. gondii
oocysts (1 × 10
5
and 1 × 10
4
oocysts). The strain, age, and concentration of the seeded oocysts were recorded. Oocysts were recovered either by centrifugation of the contaminated samples at various
g
values or by flocculation with two coagulants, Fe
2
(SO
4
)
3
and Al
2
(SO
4
)
3
. The recovery rates were determined with the final pellets by phase-contrast microscopy. Sporulated oocysts were recovered more effectively by flocculation with Al
2
(SO
4
)
3
(96.5% ± 21.7%) than by flocculation with Fe
2
(SO
4
)
3
(93.1% ± 8.1%) or by centrifugation at 2,073 ×
g
(82.5% ± 6.8%). For the unsporulated oocysts, flocculation with Fe
2
(SO
4
)
3
was more successful (100.3% ± 26.9%) than flocculation with Al
2
(SO
4
)
3
(90.4% ± 19.1%) or centrifugation at 2,565 ×
g
(97.2% ± 12.5%). The infectivity of the sporulated oocysts recovered by centrifugation was confirmed by seroconversion of all inoculated mice 77 days postinfection. These data suggest that sporulated
Toxoplasma
oocysts purified by methods commonly used for waterborne pathogens retain their infectivity after mechanical treatment and are able to induce infections in mammals. This is the first step in developing a systematic approach for the detection of
Toxoplasma
oocysts in water.
Isolation and Characterization of a Sulfur-Oxidizing Chemolithotroph Growing on Crude Oil under Anaerobic Conditions
Authors: Kodama Yumiko , Watanabe Kazuya 
Published: January 2003

ABSTRACT

Molecular approaches have shown that a group of bacteria (called cluster 1 bacteria) affiliated with the ε subclass of the class
Proteobacteria
constituted major populations in underground crude-oil storage cavities. In order to unveil their physiology and ecological niche, this study isolated bacterial strains (exemplified by strain YK-1) affiliated with the cluster 1 bacteria from an oil storage cavity at Kuji in Iwate, Japan. 16S rRNA gene sequence analysis indicated that its closest relative was
Thiomicrospira denitrificans
(90% identity). Growth experiments under anaerobic conditions showed that strain YK-1 was a sulfur-oxidizing obligate chemolithotroph utilizing sulfide, elemental sulfur, thiosulfate, and hydrogen as electron donors and nitrate as an electron acceptor. Oxygen also supported its growth only under microaerobic conditions. Strain YK-1 could not grow on nitrite, and nitrite was the final product of nitrate reduction. Neither sugars, organic acids (including acetate), nor hydrocarbons could serve as carbon and energy sources. A typical stoichiometry of its energy metabolism followed an equation: S
2−
+ 4NO
3
−
→ SO
4
2−
+ 4NO
2
−
(Δ
G
0
= −534 kJ mol
−1
). In a difference from other anaerobic sulfur-oxidizing bacteria, this bacterium was sensitive to NaCl; growth in medium containing more than 1% NaCl was negligible. When YK-1 was grown anaerobically in a sulfur-depleted inorganic medium overlaid with crude oil, sulfate was produced, corresponding to its growth. On the contrary, YK-1 could not utilize crude oil as a carbon source. These results suggest that the cluster 1 bacteria yielded energy for growth in oil storage cavities by oxidizing petroleum sulfur compounds. Based on its physiology, ecological interactions with other members of the groundwater community are discussed.
Oxygen Consumption by Anaerobic
Saccharomyces cerevisiae
under Enological Conditions: Effect on Fermentation Kinetics
Authors: Rosenfeld Eric , Beauvoit Bertrand , Blondin Bruno , Salmon Jean-Michel 
Published: January 2003

ABSTRACT

The anaerobic growth of the yeast
Saccharomyces cerevisiae
normally requires the addition of molecular oxygen, which is used to synthesize sterols and unsaturated fatty acids (UFAs). A single oxygen pulse can stimulate enological fermentation, but the biochemical pathways involved in this phenomenon remain to be elucidated. We showed that the addition of oxygen (0.3 to 1.5 mg/g [dry mass] of yeast) to a lipid-depleted medium mainly resulted in the synthesis of the sterols and UFAs required for cell growth. However, the addition of oxygen during the stationary phase in a medium containing excess ergosterol and oleic acid increased the specific fermentation rate, increased cell viability, and shortened the fermentation period. Neither the respiratory chain nor de novo protein synthesis was required for these medium- and long-term effects. As de novo lipid synthesis may be involved in ethanol tolerance, we studied the effect of oxygen addition on sterol and UFA auxotrophs (
erg1
and
ole1
mutants, respectively). Both mutants exhibited normal anaerobic fermentation kinetics. However, only the
ole1
mutant strain responded to the oxygen pulse during the stationary phase, suggesting that de novo sterol synthesis is required for the oxygen-induced increase of the specific fermentation rate. In conclusion, the sterol pathway appears to contribute significantly to the oxygen consumption capacities of cells under anaerobic conditions. Nevertheless, we demonstrated the existence of alternative oxygen consumption pathways that are neither linked to the respiratory chain nor linked to heme, sterol, or UFA synthesis. These pathways dissipate the oxygen added during the stationary phase, without affecting the fermentation kinetics.
High pH during Trisodium Phosphate Treatment Causes Membrane Damage and Destruction ofSalmonella entericaSerovar Enteritidis
Authors: Sampathkumar Balamurugan , Khachatourians George G. , Korber Darren R. 
Published: January 2003

ABSTRACTTrisodium phosphate (TSP) is now widely used during the processing of poultry and red meats, but the mechanism whereby it inactivates gram-negative bacteria suchSalmonellaspp. remains unclear. Thus,Salmonella entericaserovar Enteritidis (ATCC 4931) cells were treated with different concentrations of TSP (1.5, 2.0, and 2.5% [wt/vol]) and compared with (i) cells treated with the same pH as the TSP treatments (pH 10.0, 10.5, and 11.0, respectively) and (ii) cells treated with different concentrations of TSP (1.5, 2.0, and 2.5% [wt/vol]) adjusted to a pH of 7.0 ± 0.2 (mean ± standard deviation). Cell viability, loss of membrane integrity, cellular leakage, release of lipopolysaccharides, and cell morphology were accordingly examined and quantified under the above treatment conditions. Exposure of serovar Enteritidis cells to TSP or equivalent alkaline pH resulted in the loss of cell viability and membrane integrity in a TSP concentration- or alkaline pH-dependent manner. In contrast, cells treated with different concentrations of TSP whose pH was adjusted to 7.0 did not show any loss of cell viability or membrane integrity. A 30-min pretreatment with 1.0 mM EDTA significantly enhanced the loss of membrane integrity only when followed by TSP or alkaline pH treatments. Measuring the absorbance at 260 nm, agarose gel electrophoresis, Bradford assay, and Tricine-sodium dodecyl sulfate gel electrophoresis of filtrates of treated cell suspensions revealed considerable release of DNA, proteins, and lipopolysaccharides compared to controls and pH 7.0 TSP treatments. Electron microscopic examination of TSP- or alkaline pH-treated cells showed disfigured cell surface topology and wrinkled appearance and showed evidence of a TSP concentration- and pH-dependent disruption of the cytoplasmic and outer membranes. These results demonstrate that TSP treatment permeabilizes and disrupts the cytoplasmic and outer membranes of serovar Enteritidis cells because of the alkaline pH, which in turn leads to release of intracellular contents and eventual cell death.
Genetic Diversity and Spoilage Potentials among
Pseudomonas
spp. Isolated from Fluid Milk Products and Dairy Processing Plants
Authors: Dogan Belgin , Boor Kathryn J. 
Published: January 2003

ABSTRACT

Degradation of milk components through various enzymatic activities associated with the contamination of dairy products by
Pseudomonas
spp. can reduce the shelf life of processed milk. Reliable methods for differentiating among
Pseudomonas
spp. strains are necessary to identify and eliminate specific sources of bacterial contamination from dairy processing systems. To that end, we assessed the genetic diversity and dairy product spoilage potentials among a total of 338
Pseudomonas
spp. isolates from raw and pasteurized milk and from environmental samples collected from four dairy processing plants. The majority of isolates were identified as
P. fluorescens
and
P. putida
by API 20 NE. A total of 42 different ribotype patterns were identified among a subset of 81 isolates. The presence of many different ribotypes within this collection indicates high genetic diversity among the isolates and suggests multiple origins of contamination within the processing plant and in dairy products. The extracellular enzyme activity patterns among
Pseudomonas
isolates appeared to be associated with ribotypes. Isolates with the same ribotype frequently had the same extracellular protease, lecithinase, and lipase activities. For example, isolates grouped in ribotype 55-S-6 had the highest extracellular protease activity, while those in ribotypes 50-S-8 and 72-S-3 had the highest extracellular lipase activities. We conclude that ribotyping provides a reliable method for differentiating
Pseudomonas
strains with dairy food spoilage potential.
Thermostabilization of Bacterial Fructosyl-Amino Acid Oxidase by Directed Evolution
Authors: Sakaue Ryoichi , Kajiyama Naoki 
Published: January 2003

ABSTRACT

We succeeded in isolating several thermostable mutant fructosyl-amino acid oxidase (FAOX; EC 1.5.3) without reduction of productivity by directed evolution that combined an in vivo mutagenesis and membrane assay screening system. Five amino acid substitutions (T60A, A188G, M244L, N257S, and L261M) occurred in the most thermostable mutant obtained by a fourth round of directed evolution. This altered enzyme, FAOX-TE, was stable at 45°C, whereas the wild-type enzyme was not stable above 37°C. The

K
m

values of FAOX-TE for
d
-fructosyl-
l
-valine and
d
-fructosyl-glycine were 1.50 and 0.58 mM, respectively, in contrast with corresponding values of 1.61 and 0.74 mM for the wild-type enzyme. This altered FAOX-TE will be useful in the diagnosis of diabetes.
Novel Approach to the Improvement of Biphenyl and Polychlorinated Biphenyl Degradation Activity: Promoter Implantation by Homologous Recombination
Authors: Ohtsubo Yoshiyuki , Shimura Minoru , Delawary Mina , Kimbara Kazuhide , Takagi Masamichi , Kudo Toshiaki , Ohta Akinori , Nagata Yuji 
Published: January 2003

ABSTRACT

To improve the capabilities of microorganisms relevant for biodegradation, we developed a new genetic approach and applied it to the
bph
operon (
bphEGF
[orf4]
A1A2A3CD
[orf1]
A4R
) of
Pseudomonas
sp. strain KKS102 to enhance its biphenyl- and polychlorinated biphenyl (PCB)-degrading activity. A native promoter of the
bph
operon, which was under control, was replaced through homologous recombination by a series of promoters that had constitutive activity. By testing a series of promoters with various strengths, we were able to obtain strains that have enhanced degradation activity for biphenyl and PCBs. This strategy removes the rate-limiting factor associated with transcription and has the potential to improve the degradation activity of a wide variety of microorganisms involved in biodegradation.
Role ofctcfromListeria monocytogenesin Osmotolerance
Authors: Gardan Rozenn , Duché Ophélie , Leroy-Sétrin Sabine ,   the European Listeria Genome Consortium, Labadie Jean 
Published: January 2003

ABSTRACTListeria monocytogenesis a food-borne pathogen with the ability to grow under conditions of high osmolarity. In a previous study, we reported the identification of 12 proteins showing high induction after salt stress. One of these proteins is highly similar to the general stress protein Ctc ofBacillus subtilis. In this study, induction of Ctc after salt stress was confirmed at the transcriptional level by using RNA slot blot experiments. To explore the role of thectcgene product in resistance to stresses, we constructed actcinsertional mutant. No difference in growth was observed between the wild-type strain LO28 and thectcmutant either in rich medium after osmotic or heat stress or in minimal medium after heat stress. However, in minimal medium after osmotic stress, the growth rate of the mutant was increased by a factor of 2. Moreover, electron microscopy analysis showed impaired morphology of the mutant grown under osmotic stress conditions in minimal medium. Addition of the osmoprotectant glycine betaine to the medium completely abolished the osmotic sensitivity phenotype of thectcmutant. Altogether, these results suggest that the Ctc protein ofL. monocytogenesis involved in osmotic stress tolerance in the absence of any osmoprotectant in the medium.
Collagenolytic Serine-Carboxyl Proteinase fromAlicyclobacillus sendaiensisStrain NTAP-1: Purification, Characterization, Gene Cloning, and Heterologous Expression
Authors: Tsuruoka Naoki , Nakayama Toru , Ashida Masako , Hemmi Hisashi , Nakao Masahiro , Minakata Hiroyuki , Oyama Hiroshi , Oda Kohei , Nishino Tokuzo 
Published: January 2003

ABSTRACTEnzymatic degradation of collagen produces peptides, the collagen peptides, which show a variety of bioactivities of industrial interest.Alicyclobacillus sendaiensisstrain NTAP-1, a slightly thermophilic, acidophilic bacterium, extracellularly produces a novel thermostable collagenolytic activity, which exhibits its optimum at the acidic region (pH 3.9) and is potentially applicable to the efficient production of such peptides. Here, we describe the purification to homogeneity, characterization, gene cloning, and heterologous expression of this enzyme, which we call ScpA. Purified ScpA is a monomeric, pepstatin-insensitive carboxyl proteinase with a molecular mass of 37 kDa which exhibited the highest reactivity toward collagen (type I, from a bovine Achilles tendon) among the macromolecular substrates examined. On the basis of the sequences of the peptides obtained by digestion of collagen with ScpA, the following synthetic peptides were designed as substrates for ScpA and kinetically analyzed: Phe-Gly-Pro-Ala*Gly-Pro-Ile-Gly (kcat, 5.41 s−1;Km, 32 μM) and Met-Gly-Pro-Arg*Gly-Phe-Pro-Gly-Ser (kcat, 351 s−1;Km, 214 μM), where the asterisks denote the scissile bonds. The clonedscpAgene encoded a protein of 553 amino acids with a calculated molecular mass of 57,167 Da. Heterologous expression of thescpAgene in theEscherichia colicells yielded a mature 37-kDa species after a two-step proteolytic cleavage of the precursor protein. Sequencing of thescpAgene revealed that ScpA was a collagenolytic member of the serine-carboxyl proteinase family (the S53 family according to the MEROPS database), which is a recently identified proteinase family on the basis of crystallography results. Unexpectedly, ScpA was highly similar to a member of this family, kumamolysin, whose specificity toward macromolecular substrates has not been defined.
Coevolution of Bacteriophage PP01 and
Escherichia coli
O157:H7 in Continuous Culture
Authors: Mizoguchi Katsunori , Morita Masatomo , Fischer Curt R. , Yoichi Masatoshi , Tanji Yasunori , Unno Hajime 
Published: January 2003

ABSTRACT

The interaction between
Escherichia coli
O157:H7 and its specific bacteriophage PP01 was investigated in chemostat continuous culture. Following the addition of bacteriophage PP01,
E. coli
O157:H7 cell lysis was observed by over 4 orders of magnitude at a dilution rate of 0.876 h
−1
and by 3 orders of magnitude at a lower dilution rate (0.327 h
−1
). However, the appearance of a series of phage-resistant
E. coli
isolates, which showed a low efficiency of plating against bacteriophage PP01, led to an increase in the cell concentration in the culture. The colony shape, outer membrane protein expression, and lipopolysaccharide production of each escape mutant were compared. Cessation of major outer membrane protein OmpC production and alteration of lipopolysaccharide composition enabled
E. coli
O157:H7 to escape PP01 infection. One of the escape mutants of
E. coli
O157:H7 which formed a mucoid colony (Mu) on Luria-Bertani agar appeared 56 h postincubation at a dilution rate of 0.867 h
−1
and persisted until the end of the experiment (∼200 h). Mu mutant cells could coexist with bacteriophage PP01 in batch culture. Concentrations of the Mu cells and bacteriophage PP01 increased together. The appearance of mutant phage, which showed a different host range among the O157:H7 escape mutants than wild-type PP01, was also detected in the chemostat culture. Thus, coevolution of phage and
E. coli
O157:H7 proceeded as a mutual arms race in chemostat continuous culture.