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Mas oncogene has been shown to have focus-inducing ability in NIH 3T3 cells which are tumorigenic in vivo in nude mice. Its stable expression in a variety of cell lines conferred some angiotensin responsiveness. To understand why mas-transfected cells exhibit a transformed phenotype and if angiotensin responsiveness pl... | US |
The potential toxicity of enhanced intracellular reactive oxygen formation was investigated in isolated perfused livers of male Fischer rats. The presence of the redox-cycling agent diquat in the perfusate (200 microM) increased the basal efflux of glutathione disulfide (GSSG) into bile (2.65 +/- 0.26 nmol GSH-equivale... | US |
Adducts produced by modification of DNA with benzo[a]pyrene diolepoxide (BPDE) are known to inhibit both DNA and RNA synthesis. This phenomenon has been used as a method for determining the distribution of carcinogen binding within defined DNA sequences. A critical comparison of different enzyme activities on adducted ... | US |
A new quantitative structure-activity model for the aromatic hydrocarbon (Ah) receptor, which completely eliminates multiple regression analysis in its formulation, is reported. Taking the polychlorinated dibenzo-p-dioxins (PCDDs) as model xenobiotics, the binding affinity of a PCDD relative to 2,3,7,8-tetrachlorodiben... | US |
Stimulation of thymidine incorporation by basic fibroblast growth factor or epidermal growth factor treatment of cultured quiescent smooth muscle cells (rat and human) was attenuated by the concomitant treatment with interleukin-1 beta in the presence of indomethacin. Platelet-derived growth factor-AB and -BB-induced t... | US |
To investigate possible ionic current mechanisms underlying ischemic arrhythmias, we studied single Na+ channel currents in rat and rabbit cardiac myocytes treated with the ischemic metabolite lysophosphatidylcholine (LPC) using the cell-attached and excised inside-out patch-clamp technique at 22 degrees C. LPC has bee... | US |
The substantia nigra gamma-aminobutyric acid (GABA) system is crucial for seizure control. Our previous work indicates that in 16-day-old rat pups, nigral administration of the GABAA receptor agonist muscimol facilitates flurothyl-induced seizures, whereas it suppresses seizures in adult rats. To determine whether the ... | US |
1. Bradykinin is considered to be an important mediator of pain and hyperalgesia associated with injury and inflammation. Psychophysical studies were conducted in a patient with complete kininogen deficiency to determine whether the absence of bradykinin was associated with abnormalities in pain sensibility. Pain evoke... | US |
1. To investigate whether there is a nyctohemeral rhythm in bone turnover, we measured serum bone Gla-protein (osteocalcin, an index of osteoblast activity) concentration every 2h and urinary deoxypyridinoline (a marker of bone collagen resorption) excretion for 8h periods in 10 pubertal girls (aged 10-14 years), 15 pr... | US |
1. The metabolism of inositol-1,4,5-trisphosphate was studied in the taste organ (barbel) of the channel catfish, Ictalurus punctatus. 2. Homogenates of epithelial barbel scrapings were incubated with [3H]-1,4,5-IP3, whose dephosphorylation or phosphorylation was assayed under first-order conditions by measuring the pr... | US |
Long-term potentiation (LTP) in the hippocampus is a model system for understanding the synaptic basis of learning and memory. We have studied the mechanism of induction of LTP using voltage-clamp techniques and confocal imaging of Ca2+ in rat hippocampal slices. In the Schaffer collateral-commissural pathway the neuro... | United Kingdom |
While abundant information is available characterizing PTH receptor properties in other species, data on human PTH receptors is very limited. We have been interested in the possibility that tissue-specific differences among human PTH receptors (i.e. bone vs. kidney) might exist. We have, therefore, compared pharmacolog... | US |
The objective of this study was to determine if kappa-opioid receptors present in the medial preoptic area (MPOA) and medial basal hypothalamus (MBH) are involved in opioid peptide suppression of LH secretion during midpregnancy (day 13-16) in the rat. Nor-binaltorphimine (nor-BNI), a selective antagonist of brain kapp... | US |
We found previously that the level of endogenous TRH receptor (TRH-R) mRNA in pituitary (GH3) cells and the level of mouse TRH-R mRNA in GH3 cells stably transfected with mouse pituitary TRH-R cDNA are down-regulated by TRH. This down-regulation is caused by TRH stimulation of TRH-R mRNA degradation via a mechanism tha... | US |
We have reported that pretreatment of human SaOS-2 osteoblast-like cells with forskolin (Fsk; 10(-5) M) for 4 h strikingly inhibited subsequent cAMP responsiveness to a second challenge with Fsk (Fsk-induced homologous desensitization) without altering the responses to PTH or vasoactive intestinal peptide (VIP). Pretre... | US |
The mouse anterior pituitary-derived cell line AtT-20 has been widely used to study the biosynthesis and secretion of peptide hormones, such as ACTH, and peptide-processing enzymes, such as carboxypeptidase-E (CPE). Although AtT-20 cells do not express dynorphin (Dyn), previous studies using gene transfer have revealed... | US |
Cobalt (Co), nickel (Ni), manganese (Mn), cadmium (Cd), and lanthanum (La) are commonly used as calcium (Ca) channel blockers, but some of them, besides reducing Ca entry, also traverse Ca channels and can exert effects intracellularly that confound interpretation of functional responses. Because of this and our need t... | US |
Short-term exposure of rats to aerosols of the silicon dioxide, cristobalite, leads to pulmonary inflammation persisting several months. Clearance of particles occurs during the first two weeks after cessation of exposure, after which there is little additional clearance in the whole lung. In the present studies, quant... | US |
The authors review some of their experimental data on the contribution of Na(+)- and K(+)-dependent adenosine triphosphatase (Na+,K(+)-ATPase) to focal epilepsy. It has been previously demonstrated that high extracellular K+ concentration increases glial Na+,K(+)-ATPase specific activities in normal conditions while th... | US |
Respiratory deficient pet mutants of Saccharomyces cerevisiae assigned to complementation group G2 define a new gene, named BCS1, whose product is shown to be necessary for the expression of functional ubiquinol-cytochrome c reductase (bc1) complex. Immunological assays indicate a gross reduction in the Rieske iron-sul... | US |
Clam oocytes are arrested naturally at the G2/M border in meiosis and contain an inactive 42 kDa ERK/MAP kinase, p42MAPK. Following fertilization, p42MAPK is rapidly phosphorylated on tyrosine residues and concomitantly activated. Both tyrosine phosphorylation and activation of p42MAPK begin within 2-3 min of fertiliza... | US |
In an effort to determine how crude gradients of transcriptional activators and repressors specify sharp stripes of gene expression in the early embryo, we have conducted a detailed study of even-skipped (eve) stripe 2. A combination of promoter fusions and P-transformation assays were used to show that a 480 bp region... | US |
We report that compartmentalisation of the stimulatory guanine-nucleotide-binding regulatory protein (Gs) exists in S49 lymphoma cells. In addition to the previously reported cytosolic form of the alpha subunit of Gs (Gs alpha) [Ransnäs, L. A., Svoboda P., Jasper, J. R. & Insel, P. A. (1989) Proc. Natl Acad. Sci. USA 8... | US |
Experiments were designed to test whether T cell progenitors are committed to particular T cell receptor (TcR) gene rearrangement and expression patterns (prior to rearrangement) or whether such patients are molded by the thymic microenvironment in which T cells develop. To this end, day 14 fetal thymocytes were remove... | US |
We have investigated the ability of an array of putative noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonists to suppress convulsions induced by a unilateral, focal injection of (-)-bicuculline methiodide (118 pmol) into the rat prepiriform cortex. The anticonvulsant potency of these compounds, (+)-5-methyl-... | US |
This study determined the influence of nor-binaltorphimine (nor-BNI, 10 micrograms intracisternally), 1, 7 and 21 days post-administration, upon spiradoline-induced antinociception measured in the hot-plate test. On each test day, nor-BNI prevented the spiradoline-induced increase in the latency of rats to paw-lick wit... | US |
TRIMU-5 (Tyr-D-Ala-Gly-NH-(CH2)2CH(CH3)2) is a potent enkephalin analog with analgesic actions. Detailed studies show high affinity for both mu 1 and mu 2 sites, with poor affinity for delta, kappa 1 and kappa 3 receptors. Of all the mu ligands examined in binding assays, TRIMU-5 was the most mu-selective. In mice, TRI... | US |
The effects of cromakalim and its active enantiomer BRL 38226 on voltage-gated Ca2+ channels in smooth muscle cells isolated from human mesenteric arteries were studied using the whole cell patch-clamp technique. Neither of these drugs affected the Ca2+ channel current in these cells. These results suggest that the eff... | United Kingdom |
5-(2'-[18F]Fluoroethyl)flumazenil ([18F]FEF), a fluorine-18-labeled analogue of the benzodiazepine antagonist flumazenil, was evaluated for use with positron emission tomography (PET). PET imaging of a baboon after i.v. injection of [18F]FEF showed that the radiofluorinated ligand rapidly localized in vivo within benzo... | US |
Effects of taurine on the fast Na+ current (INa) in 17-day-old embryonic chick ventricular myocytes were examined using the whole-cell voltage-clamp technique. The cells were spherical (10-15 microns diameter) and had a capacitance of 9.8 +/- 1.3 pF. The experiments were performed at room temperature (22 degrees C), an... | US |
Receptor binding site(s) on the rat urinary bladder membranes were characterized using a biologically active analog of bombesin, [Tyr4,Leu14]bombesin, and a 50,000 x g total particulate preparation. The binding was specific, reversible, saturable, time- and concentration-dependent. A dissociation curve showed that both... | US |
Levels of mRNA for the alpha 1, gamma 2 and beta 1 subunits of the GABAA receptor complex were examined in rats maintained on a chronic, continuous schedule of exposure to the benzodiazepine inverse agonist FG 7142. The effect of chronic exposure to the benzodiazepine agonist diazepam was also examined on levels of gam... | US |
The influence of the membrane environment on the alpha 1-adrenoceptor has been investigated by examining the effect of phospholipase digestion on the binding of [3H]prazosin to aortic and hepatic membranes. Membrane digestion by phospholipase A2 and phospholipase C was found to markedly reduce prazosin binding to the a... | US |
We have previously reported that dopamine and the D1 receptor-selective agonist, SKF38393, stimulate the formation of inositol phosphates in rat brain slices (Undie and Friedman, 1990, J. Pharmacol. Exp. Ther. 253, 987). The present experiments were conducted to determine if actions at alpha-adrenoceptors or at seroton... | US |
We studied the effect of repeated administration of electroconvulsive shock (ECS) on alpha 1-adrenoceptor subtype (alpha 1A and alpha 1B) and 5-HT2 (serotonin-2) receptors and receptor-mediated phosphoinositide (PI) hydrolysis in rat cerebral cortex. We observed that repeated administration with ECS significantly incre... | US |
In the dog iris sphincter, muscarinic acetylcholine receptors are coupled either to the stimulation of phospholipase C and muscle contraction or to the stimulation of adenylate cyclase and muscle relaxation, this was found to be dependent upon the concentration of the muscarinic agonist. In contrast to the dog, muscari... | US |
The molecular mechanism of the clinical antiepileptic/antimyoclonic action of adrenocorticotrophic hormone (ACTH) is unknown. To explore the possible role of excitatory amino acid receptors, we studied the influence of ACTH and ACTH fragments in vitro on the binding of [3H]MK-801 to rat hippocampus, a region relevant t... | US |
The clinical phenotype of Werner's syndrome (WS) includes short stature, premature cataracts, skin atrophy, osteoporosis, graying and loss of hair, neoplasia, diabetes mellitus, and arteriosclerosis. Cultured cells from patients with this autosomal recessive disorder exhibit chromosomal instability and a markedly reduc... | US |
Polyphosphoinositide isomers have been demonstrated to be important mediators of cell proliferation in vitro. The present study demonstrates, for the first time, the in vivo formation of the novel isomer, phosphatidylinositol(3)phosphate, in the kidney and liver of intact animals following intraperitoneal administratio... | US |
The most promising nucleoside analogs that are currently undergoing preclinical and clinical testing for anti-HIV activity belong to the dideoxynucleoside group. We have studied the toxicity of 3'-azido,3'-deoxythymidine (AZT), 2',3'-dideoxycytidine (DDC), and 2',3'-dideoxyinosine (DDI) in canine bone marrow progenitor... | US |
The heme propionate substituents in Pseudomonas cytochrome c-551 are partially buried by folds of polypeptide in the structure of the protein, and are involved in several hydrogen bonds. The ionization behavior of these groups has been of interest because the oxidation potential of the heme changes with pH in a manner ... | US |
1. Inositol 1,4,5-trisphosphate (IP3), an intracellular second messenger, has been shown to be the link between activation of several plasma membrane receptors and Ca2+ release from intracellular, membrane-bound compartments. In this study, the postnatal expression of the canine cerebellum IP3 receptor was investigated... | US |
We have used fluorescence ratio-imaging of fura-2 in the activating egg of Xenopus laevis to study the wave of increased intracellular free Ca2+ concentration ([Ca2+]i) while monitoring that of cortical granule exocytosis. Naturally matured eggs were dejellied, injected with fura-2, and activated by the iontophoresis o... | US |
Classical concepts of the regulation of plasma cholesterol levels involve roles for the "forward" delivery of low density lipoprotein (LDL) cholesterol from the liver to the peripheral tissues, mediated by the LDL receptor, and a "reverse" delivery of cholesterol in the form of high density lipoprotein (HDL) from the p... | US |
Steady-state analyses were performed on the proopiomelanocortin (POMC)-related end-products present in acid extracts of the pars intermedia of the anuran amphibian, Bombina orientalis. Sephadex G-75 gel filtration chromatography indicated that immunoreactive alpha-MSH-sized material and N-acetylated beta-endorphin-rela... | US |
The hyper-gene conversion srs2-101 mutation of the SRS2 DNA helicase gene of Saccharomyces cerevisiae has been reported to suppress the UV sensitivity of rad18 mutants. New alleles of SRS2 were recovered using this suppressor phenotype. The alleles have been characterized with respect to suppression of rad18 UV sensiti... | US |
The cyc1-362 mutant of Saccharomyces cerevisiae is deficient in iso-1-cytochrome c as a consequence of an aberrant ATG codon that initiates a short open reading frame (uORF) in the cyc1 transcribed leader region. We have isolated and characterized functional revertants of cyc1-362 in an effort to define cis- and trans-... | US |
Expression of the yellow (y) gene of Drosophila melanogaster is controlled by a series of tissue-specific transcriptional enhancers located in the 5' region and intron of the gene. Insertion of the gypsy retrotransposon in the y2 allele at -700 bp from the start of transcription results in a spatially restricted phenot... | US |
The expression of the yeast CYC1 and CYC7 genes is controlled by the HAP1 activator. A GAL4-like zinc finger (residues 1-148) specifies binding to the dissimilar sites UAS1 (of CYC1) and CYC7, and an acidic domain (residues 1307-1483) is essential for activation of transcription. To analyze how HAP1 binds to UAS1 and C... | US |
To facilitate the use of a wide range of selectable markers in transfection studies with human cells, in conjunction with the use of modulatable promoters for regulated expression of the genes of interest, we constructed two pUC19-based mammalian expression vectors, each containing two lacZ alpha-based multiple cloning... | US |
In current systems for molecular cloning of eukaryotic genes, bacterial cells are routinely utilized as intermediate hosts. We investigated the possibility of using a viral system for cloning DNA fragments independent of bacterial cell usage. In this report, we provide an alternative approach for molecular cloning of D... | US |
Subunit VIa of mammalian cytochrome c oxidase (COX; EC 1.9.3.1) exists in two isoforms, one present ubiquitously ('liver' isoform; COX VIa-L) and the other present only in cardiac and skeletal muscle (COX VIa-M). We have now isolated a full-length cDNA specifying human COX VIa-M. The deduced mature COX VIa-M polypeptid... | US |
Subunit VIIa of mammalian cytochrome c oxidase (COX; EC 1.9.3.1) exists in at least two isoforms, one present in all tissue types ('liver' isoform; COX VIIa-L) and the other specific for cardiac and skeletal muscle (COX VIIa-M). We have isolated a full-length cDNA encoding human COX VIIa-M. The deduced polypeptide repr... | US |
Genes encoding proteins with unrelated functions can be cotranscribed, and this may be used by cells to coordinate different metabolic pathways during growth. We describe a gene, designated sms, which is downstream from the serine biosynthetic gene serB in Escherichia coli but does not appear to be involved in amino ac... | US |
Seven new streptococcal integration shuttle vectors have been constructed which contain different antibiotic-resistance-encoding genes capable of expression in both Streptococcus sp. and Escherichia coli. These plasmids can replicate in E. coli, but not in streptococci because of the absence of a streptococcal origin o... | US |
To explore the role played by beta adrenoreceptor mediated pathways on human upper gut function a series of studies were conducted into the effects of beta adrenoreceptor agonists and antagonists on orocaecal and duodenocaecal transit and on antral and duodenal motor activity. Under control conditions orocaecal transit... | United Kingdom |
A PCR-based method was used to screen 462 individuals from Japan, Papua New Guinea, Indonesia, and Australia for an Alu family insertion polymorphism. The frequency of this Alu insertion shows significant heterogeneity among island subgroups of the Indonesian sample and between the Japanese-Indonesian populations and t... | US |
The relationship of age and of level of adaptive functioning to comorbidity of mental disorders among alcoholics was studied in a survey of all alcoholics seeking outpatient mental health treatment in the Veterans Affairs mental health care system during a one-month period in 1986 (N = 22,463). More than half of the al... | US |
Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) have been shown to be secreted by distinct T-helper cell subsets which have different roles in the determination of host resistance to infection. We studied the activity of these two cytokines on effector mechanisms of mouse macrophages. In vitro cultured bone marro... | US |
Lymphocyte activation requires signal transduction mediated by reversible phosphorylation. Changing profiles of phosphorylated intermediates relate to the progressive series of transduction pathways in cells moving from G0 to G1, and thereafter through the cell cycle. We have previously shown that transient inhibition ... | United Kingdom |
In this investigation we correlated platelet Na-H antiport parameters with blood pressure and serum lipids in a sample population of non-insulin-dependent diabetic obese, nondiabetic obese, and nondiabetic nonobese black women. Parameters of the Na-H antiport were examined in aspirin-treated platelets. These parameters... | US |
Attempts to show the distribution of adrenergic receptors (ARs) in autoradiographs of a brainstem motor nucleus following elimination of motor neurons yielded the unexpected result of an increase in beta-AR density. This increase was related to the gliosis accompanying the motor neuron degeneration. To determine the ce... | US |
Using the whole-cell patch-clamp technique, at least three types of voltage-gated currents expressed by cultured rat microglia were identified: an inward rectifier K+ current, a delayed rectifier K+ current (IK), and a Na+ current activated by depolarization. The inward rectifier conductance was activated by hyperpolar... | US |
Interleukin-6 (IL-6) is a cytokine produced by a number of cells, including macrophages, and is directly involved in the inflammatory response. The production of IL-6 can be stimulated by monokines such as IL-1 and tumor necrosis factor (TNF). Mycobacterium avium complex organisms frequently cause disseminated disease ... | US |
Delayed-type hypersensitivity (DTH) is the standard measure of T-cell responsiveness to infectious organisms. For leprosy, the Mitsuda reaction, a local immune response to cutaneous challenge with Mycobacterium leprae, is considered to represent a measure of DTH against the pathogen. We analyzed the diversity of the T-... | US |
The prevalence and associated cytologic manifestations of cervical infection with human papillomavirus (HPV) types 6, 11, 16, 18, 31, 33, 35, 42, 43, 44, 45, 51, 52, and 56 were studied among 500 consecutive women attending the Harborview Medical Center Sexually Transmitted Diseases (STD) Clinic in Seattle, WA. Using r... | US |
Nuclear enlargement of the superficial cervical epithelial cells in the absence of koilocytosis is frequently observed. The purpose of this study was to investigate whether this change represents human papillomavirus (HPV) infection. We reviewed 257 cervical biopsies with the diagnosis of "suggestive of condyloma," mil... | US |
Pregnancy is thought to be a major contributor to the excess prevalence of obesity in women compared to men. Pregnancy-related increases in weight are purported to increase the risk that women will develop chronic diseases associated with high body weight. The assertion that pregnancy is associated with permanent weigh... | US |
Taste preferences for sensory stimuli composed of sugar and fat are predictive of some food preferences and may help distinguish between potential subtypes of human obesity. A sample of 37 obese females was divided into high-flux and low-flux groups according to the magnitude of fluctuations in body weight. Variability... | US |
The National Heart, Lung, and Blood Institute (NHLBI) Twin Study provided longitudinal data on a cohort of 514 pairs of adult male twin pairs who were examined at approximate ages of 48, 57, and 63 years. Because the sample was selected from military veterans, height and weight data were also available from their induc... | US |
Studies of twins and adoptees have shown that the resemblance of adult family members in body mass index (weight/height2) is due more to shared genes than to shared rearing environment. In the present adoption study we assessed the genetic and environmental influences on body mass index in childhood. Among 3651 adult D... | US |
This study was designed to investigate the relative ability of a series of cyclic opioid peptides to initiate the first activation steps following their binding of delta-opioid receptors. The extent of stimulation of low Km guanosine-triphosphatase (GTPase activity) and inhibition of hormonally-stimulated cAMP accumula... | US |
A detailed comparison of intracellular pH (pHi) regulatory mechanisms was made between fresh (FBCE) and cultured (CBCE) bovine corneal endothelium to: (1) identify the ion transport mechanisms that could directly or indirectly affect transendothelial HCO3- transport; and (2) determine if cultured cells could serve as a... | US |
cAMP production was investigated in retinal pigment epithelium (RPE) cells isolated from normal rats and from rats with an inherited retinal dystrophy (Rdy/p+). In normal RPE cells, 5'-[N-Ethylcarboxamido]-adenosine (A2 receptors) produced a fivefold increase in the level of cyclic adenosine monophosphate (cAMP) over b... | US |
Intraocular pressure (IOP) decreases in rabbits 1 day after superior cervical ganglionectomy. It was hypothesized that this IOP decrease was caused by an accumulation of norepinephrine (NE) released from the iris-ciliary body into the aqueous humor during nerve degeneration. Direct measurement of aqueous humor NE conce... | US |
In plate matings with Escherichia coli HB101/pUW965::Tn5 (KmR) Thiobacillus versutus reacted as an efficient recipient, producing 10(-2) to 10(-3) kanamycin resistant (KmR) T. versutus exconjugants per donor cell. Analysis of agarose gels of plasmid DNA extracted from the exconjugants confirmed that the suicide vector ... | US |
We investigated the effects of an intravenous (pentobarbital sodium) and an inhalational (halothane) general anesthetic on guanosine 3',5'-cyclic monophosphate- (cGMP) mediated pulmonary vasodilation compared with responses measured in the conscious state. Multipoint pulmonary vascular pressure-flow plots were generate... | US |
Alveolar macrophages release greater amounts of leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) after A23187 stimulation than do blood monocytes. The mechanisms for this enhanced 5-lipoxygenase activity in alveolar macrophages are unknown. In these studies, we determined whether alveolar macrophages h... | US |
DNA cloned into Escherichia coli K-12 from a serotype c strain of Streptococcus mutans encodes three enzyme activities for galactose utilization via the tagatose 6-phosphate pathway: galactose 6-phosphate isomerase, tagatose 6-phosphate kinase, and tagatose-1,6-bisphosphate aldolase. The genes coding for the tagatose 6... | US |
The mercury resistance (mer) operon of the gram-negative transposon Tn21 encodes not only a mercuric reductase and regulatory genes but also two inner membrane proteins (MerT and MerC) and a periplasmic protein (MerP). Although the merT, merP, and merC genes have been implicated in Hg(II) transport, the individual role... | US |
Pantothenate kinase catalyzes the rate-controlling step in coenzyme A (CoA) biosynthesis. The structural gene (coaA) located at 90 min of the Escherichia coli chromosome was cloned and sequenced. The coaA gene was transcribed in the opposite direction to the flanking genes birA and thrU and produced a single 1.1-kb tra... | US |
In a screen for Escherichia coli genes whose products are required for high-temperature growth, we identified and characterized a mini-Tn10 insertion that allows the formation of wild-type-size colonies at 30 degrees C but results in microcolony formation at 36 degrees C and above (Ts- phenotype). Mapping, molecular cl... | US |
The genes required for use of ethanolamine as a carbon and nitrogen source are encoded by a single operon (eut) whose expression is induced by the simultaneous presence of both ethanolamine and cobalamin (vitamin B12). The action of B12 as an inducer of this operon reflects the fact that this cofactor is required by th... | US |
D55Q-T83A and D55Q-G94S, two pseudorevertants of the D55Q mutant OmpR, an Escherichia coli transcriptional activator, were isolated previously by R. Brissette, K. Tsung, and M. Inouye (J. Bacteriol. 173:3749-3755, 1991). These pseudorevertant OmpR proteins were purified and examined for their function as transcriptiona... | US |
We have shown that excision and transposition of Tn5 in Escherichia coli are greatly increased by recA(Prtc) genes, which encode constitutively activated RecA proteins (C.-T. Kuan, S.-K. Liu, and I. Tessman, Genetics 128:45-57, 1991). Contrary results, showing a significant decrease in Tn5 transposition under SOS condi... | US |
Anaerobic expression of the tdcABC operon of Escherichia coli requires cyclic AMP and the catabolite gene activator protein (CAP). Purified CAP binds to a 30-bp sequence in the tdc promoter between positions -55 and -26, and a mutant CAP site with base substitutions at positions -48, -47, and -45 failed to bind CAP and... | US |
The gram-negative bacterium Salmonella typhimurium possesses three distinct Mg2+ transport systems, encoded by the corA, mgtA, and mgtB loci. The CorA transport system is the constitutive Mg2+ influx system. It can also mediate Mg2+ efflux at very high extracellular Mg2+ concentrations. In contrast, the MgtA and MgtB M... | US |
1,3-Butadiene was oxidized by human myeloperoxidase in the absence of KCl to yield butadiene monoxide (BM) and crotonaldehyde (CA), but at KCl concentrations higher than 50 mM, 1-chloro-2-hydroxy-3-butene (CHB) was the major metabolite detected; metabolite formation was dependent on incubation time, pH, KCl, 1,3-butadi... | US |
In order to determine the effect of calcium mobilization on mitogen-activated protein (MAP) kinase activation, we have treated human foreskin fibroblasts (HSWP cells) and human epidermal carcinoma (A431) cells with thapsigargin. Intracellular free calcium was monitored by single cell image analysis using fura-2 and cor... | US |
The respiratory burst oxidase is a multimeric enzyme responsible for O2- production by stimulated neutrophils and a few other cell types. In the resting neutrophil, the oxidase is dormant, and its subunits are distributed between the cytosol, in which they appear to exist in the form of a multisubunit complex, and the ... | US |
Phosphatidylinositol-specific phospholipase C (PtdIns-PLC) of Bacillus cereus catalyzes the conversion of PtdIns to inositol cyclic 1:2-phosphate and diacylglycerol. NIH 3T3, Swiss mouse 3T3, CV-1, and Cos-7 cells were transfected with a cDNA encoding this enzyme, and the metabolic and cellular consequences were invest... | US |
Inositol 2-phosphate (Ins(2)P) has been identified in several cell types. The cellular levels of Ins(2)P appear to be directly correlated with the levels of inositol 1:2-cyclic phosphate (cIns(1:2)P) (Ross, T. S., Wang, F. P., and Majerus, P. W. (1992) J. Biol. Chem. 267, 19919-19923). In this study we have detected an... | US |
Unlike wild type, certain Mo-dependent nitrogenases, which are expressed in non-N2-fixing mutant strains of Azotobacter vinelandii and have single amino acid substitutions within a region of the MoFe protein alpha-subunit proposed to encompass an FeMo cofactor-binding domain, are able to catalyze the reduction of acety... | US |
Several studies have shown that the 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) receptor protein levels increase in response to 1,25-(OH)2D3. We have studied the mechanism of this regulation in both mouse fibroblasts and rat intestinal epithelial cells. Cell extracts and total RNA were prepared at varying times after addit... | US |
We have studied the effects of thrombin (alpha-thrombin) and Ser-Phe-Leu-Leu-Arg-Asn-Pro-Asn-Asp-Lys-Tyr-Glu-Pro-Phe (SFLL), a peptide agonist of the platelet thrombin receptor in cultured human mesangial cells, and find that SFLL can reproduce the biochemical and morphological effects of thrombin. Treatment of mesangi... | US |
Cytochrome c reductase purified from the trypanosomatid Crithidia fasciculata retained antimycin A sensitivity and catalyzed the reduction of horse heart ferricytochrome c in the presence of reduced coenzyme Q10. The complex contained heme b and heme c1 in a ratio of 2:1. Nine major protein bands ranging in size from 5... | US |
We reported previously that a 32-36-kDa osteogenic protein purified from bovine bone matrix is composed of dimers of two members of the transforming growth factor (TGF)-beta superfamily: the bovine equivalent of human osteogenic protein-1 (OP-1) and bone morphogenetic protein-2a, BMP-2a (BMP-2). In the present study, w... | US |
The gene encoding a novel mouse somatostatin receptor termed mSSTR3 was isolated and characterized. The sequence of mSSTR3 shows 46 and 47% identity with mSSTR1 and mSSTR2, respectively. mSSTR3 binds somatostatin-14 and somatostatin-28 with high affinity, but shows very low affinity for the somatostatin analogs MK-678 ... | US |
Propranolol, a beta-adrenergic receptor antagonist, also inhibits phosphatidate phosphohydrolase, the enzyme that converts phosphatidic acid into diacylglycerol. This latter effect has prompted recent use of propranolol in studies examining the importance of diacylglycerol and phosphatidic acid in cellular signalling e... | US |
The catalytic activity of topoisomerase II is stimulated approximately 2-3-fold following phosphorylation by casein kinase II (Ackerman, P., Glover, C. V. C., and Osheroff, N. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 3164-3168). In order to delineate the mechanism by which the activity of the enzyme is enhanced, the ... | US |
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