Antimutagenic effect of umuD mutant plasmids: isolation and characterization of umuD mutants reduced in their ability to promote UV mutagenesis in Escherichia coli.
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Amino Acid Sequence↗
Biomedical subjects
W Sun
Publications and source records attributed to W Sun.
Dominant negative umuD mutations decreasing RecA-mediated cleavage suggest roles for intact UmuD in modulation of SOS mutagenesis.
The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. The UmuD protein shares homology with a family of proteins that includes LexA and several bacteriophage repressors. UmuD is posttranslationally activated for its role in mutagenesis by a RecA-mediated proteolytic cleavage that yields UmuD'. A set of missense mutants of umuD was isolated and shown to encode mutant UmuD proteins that are deficient in RecA-mediated cleavage in vivo. Most of these mutations are dominant to umuD+ with respect to UV mutagenesis yet do not interfere with SOS induction. Although both UmuD and UmuD' form homodimers, we provide evidence that they preferentially form heterodimers. The relationship of UmuD to LexA, lambda repressor, and other members of the family of proteins is discussed and possible roles of intact UmuD in modulating SOS mutagenesis are discussed.
Amino Acid Sequence↗
[Quantitative determination of strychnine and brucine in semen Strychni and its preparations by gas chromatography].
Contents of strychnine and brucine in dry seeds of Strychnos nux-vomica and its preparations were determined by gas chromatography. The determination conditions were:support Gas Chrom Q; liquid phase 3% OV-101; stainless steel column 0.5 m x 3 mm; column temperature 265 degrees C; FID detector.
Chromatography, Gas↗
[Analysis of amino acids in hemolymph and acid hydrolysates of midguts of Anopheles dirus infected with Plasmodium cynomolgi].
Quantitative determinations of free amino acids in hemolymph and acid hydrolysates of midguts of female Anopheles dirus infected with Plasmodium cynomolgi bastianellii were carried out and the results were compared with those of noninfected mosquitoes. On day 10 after infected blood meal, the contents of methionine, isoleucine, leucine, ornithine, lysine in the hemolymph of infected mosquitoes markedly decreased as compared with those in the controls. However, the quantitative analysis of the amino acids of the acid hydrolysates of the midguts from infected mosquitoes on day 9 after an infected blood meal showed that the content of their total amino acids was 70% more than that in the controls, with special reference to aspartic acid, glutamic acid, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan.
Amino Acids↗
External application of the renal failure recipe on acupoints for the treatment of uremia in 8 cases.
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Acupuncture Points↗
Photodetachment cross section for the 3 sigma u channel of F2- in the static-exchange approximation.
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Journal Article↗
[Study of mechanisms in the pathogenesis of myelodysplastic syndrome: changes in lymphocyte subpopulations].
The mechanism of pathogenesis in myelodysplastic syndrome (MDS) is still unknown up to the present day, but examination of blood and bone marrow from 22 patients with MDS showed that the majority had low lymphocyte counts in bone marrow. Using monoclonal antibodies (MoAbs) OKT3, OKT4 and OKT8 combined with SRBC rosettes, the authors found that there was a significant decrease of OKT3-defined Pan-T lymphocytes in peripheral blood. This reduction was primarily confined to the OKT4-defined helper subset, but there was a relative increase in the OKT8-defined suppressor subpopulation. As a result, the ration OKT4/OKT8 was reversed. The data of MLC test also showed abnormalities of cell-mediated immunity function in the patients. The significance of these observed changes in the pathogenesis of MDS was discussed.
Adolescent↗
In vitro studies on the nucleocapsid-associated RNA polymerase of wheat rosette stunt virus.
RNA-dependent RNA polymerase activity was detected in both virion and nucleocapsid preparations of wheat rosette stunt virus, a plant rhabdovirus. The presence of nonionic detergent such as Nonidet P40 was essential for activity in reaction mixtures containing virions. The polymerase product was proved to be single-stranded RNA. By two-step controlled dissociation of the nucleocapsids, four subviral fractions (L protein, NS-N-RNA complex, NS protein, and N-RNA complex) were prepared. None of these fractions showed RNA polymerase activity when assayed individually. In experiments combining the various fractions, RNA synthesis was observed only when the L and NS proteins and the N-RNA complex were present in reaction mixtures.
Capsid↗
[Effect of panaxadiol-saponins from ginseng flowers and leaves on DNA synthesis in mouse ascitic reticulocytic sarcoma cells].
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Animals↗
Na, K-ATPase isoform gene expression in normal and hypertrophied dog heart.
OBJECTIVES: The catalytic alpha subunit of the sodium-potassium ATPase, the target of digitalis glycosides, has three isoforms; the expression of these isoforms is tissue-specific and developmentally regulated. While the effect of pressure overload on Na, K-ATPase isoform expression has been studied in rodent heart, there are no systematic data on this question in hearts of larger animals, which differ from those of rodents both in isoform composition and in glycoside sensitivity. Thus, we investigated the expression of Na, K-ATPase isoforms in normal dog heart; we also examined the effect of experimental left ventricular hypertrophy on isoform expression. METHODS: hypertrophy was produced by aortic banding. Expression was assessed by quantitative Northern and Western blotting, immunofluorescence, and 3H-ouabain binding. RESULTS: RNA blotting indicated that the alpha 3 isoform represented 11% of Na, K-ATPase mRNA in normal dog LV. Normal dog LV expressed alpha 1 and alpha 3 protein, but no detectable alpha 2; immunoreactive alpha 1 and alpha 3 protein were also present in Purkinje fibers. There was a statistically significant decrease in total expression of all alpha isoform mRNA's in hypertrophied dog LV, resulting in a greater proportion of alpha 1. The expression level of the alpha 3 isoform mRNA and protein was lower in hypertrophied hearts. CONCLUSIONS: These results indicate a greater proportion of alpha 1 isoform pumps in experimental canine hypertrophy. Thus, shifts in NA, K-ATPase isoforms occur in pressure-overloaded heart in large animals as well as rodents.
Analysis of Variance↗
NADPH-diaphorase reactivity in ciliary ganglion neurons: a comparison of distributions in the pigeon, cat, and monkey.
Ciliary ganglia from the pigeon, cat, and monkey were investigated for the presence of NADPH-diaphorase reactivity by use of a standard histochemical method. In the pigeon, where the ganglion is known to control lens and pupil function, and the choroidal vasculature, about one-third of the ganglion cells were densely stained and most other somata were lightly stained. In some cases, preganglionic terminals with a cap-like morphology were also darkly stained. The pattern of NADPH-diaphorase staining in mammals was very different from that seen in pigeons. In both mammalian species, where the ganglion is known to control lens and pupil function, a small number (less than 2%) of the ganglion cells were shown to be densely NADPH-diaphorase positive, revealing their neuronal processes. The presence of NADPH-diaphorase positive cells in pigeon, cat, and monkey ciliary ganglia suggests that nitric oxide may be used for intercellular communication in this ganglion, or in light of the known importance of nitric oxide in vascular control, some of these positive neurons may participate in the control of choroidal vasodilation.
Animals↗
The signal transduction pathway causing the synergistic hypertrophic effects of neuropeptide Y and norepinephrine on primary cardiomyocyte.
To investigate the synergistic hypertrophic effects of neuropeptide Y (NPY) and norepinephrine (NE) and its possible signal transduction pathway on primary cardiomyocytes, neonatal cardiomyocytes were exposed to NPY, NE or angiotensin II (AnII). All three agonists induced hypertrophic effects, stimulated protein kinase C (PKC) and activated mitogen-activated protein kinase (MAPK). Moreover, NPY at sub-optimal concentration potentiated NE-, not AnII-, induced all of the above effects. Pretreatment with phorbol 12-myristate 13-acetate (PMA) completely abolished these effects for both NE and NPY. NPY potentiation was calcium-independent and pertussis toxin (PTX)-sensitive, and was different from NPY direct hypertrophic effect on cardiomyocyte, as PTX only partially abolished NPY-induced hypertrophic effects. Taken together, NPY participated in the development of cardiac hypertrophy by potentiating NE effects. The signal pathway involves PTX-sensitive G protein, PKC, MAPK, and does not require the presence of calcium.
Adrenergic alpha-Agonists↗
Genotype-phenotype correlation and frequency of the 3199del6 cystic fibrosis mutation among I148T carriers: results from a collaborative study.
PURPOSE: We expect that the mutation panel currently recommended for preconception/prenatal CF carrier screening will be modified as new information is learned regarding the phenotype associated with specific mutations and allele frequencies in various populations. One such example is the I148T mutation, originally described as a severe CF mutation. After implementation of CF population-based carrier screening, we learned that I148T exists as a complex allele with 3199del6 in patients with clinical CF, whereas asymptomatic compound heterozygotes for I148T and a second severe CF mutation were negative for 3199del6. METHODS: We performed reflex testing for 3199del6 on 663 unrelated specimens, including I148T heterozygotes, compound heterozygotes, and a homozygous individual. RESULTS: Less than 1% of I148T carriers were also positive for 3199del6. Excluding subjects tested because of a suspected or known CF diagnosis or positive family history, 0.6% of I148T-positive individuals were also positive for 3199del6. We identified 1 I148T homozygote and 6 unrelated compound heterozygous individuals with I148T and a second CF variant (2 of whom also carried 3199del6). In addition, one fetus with echogenic bowel and one infertile male were heterozygous for I148T (3199del6 negative). CONCLUSIONS: Reflex testing for 3199del6 should be considered whenever I148T is identified. Reflex testing is of particular importance for any symptomatic patient or whenever one member of a couple carries a deleterious CF mutation and the other member is an I148T heterozygote. Further population data are required to determine if I148T, in the absence of 3199del6, is associated with mild or atypical CF or male infertility.
Cystic Fibrosis↗
Catalase activity of chloroperoxidase and its interaction with peroxidase activity.
The catalatic activity of chloroperoxidase (CPO) was demonstrated to exhibit saturation kinetics under steady-state conditions, which were not observed with catalase under comparable conditions. Results were obtained using reaction mixtures of CPO and H2O2 at pH 6.2, rapid spectral scan and single wavelength measurements, and transient- and steady-state reaction conditions. The observed rectangular hyperbolae (measurement of rates of disappearance of H2O2 and appearance of O2) could be fit quantitatively to [equation: see text] where v is rate of O2 evolution, [CPO]0 is total enzyme concentration, B1 = (9 +/- 1) x 10(2) s-1, and B2 = (3.3 +/- 0.4) x 10(-3) M. The results indicated formation of a complex of compound I (CPO-I) and H2O2, which dissociated to native CPO, O2, and H2O with a rate constant of (9 +/- 1) x 10(2) s-1. The determination of the peroxidatic activity of CPO was performed using demethylation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) under steady-state conditions. Attempts to determine Michaelis-Menten constants for the substrates TMPD and H2O2 gave rise to apparently anomalous data. Our data showed that the modified ping-pong mechanism established for horseradish peroxidase is applicable to the peroxidatic reaction catalyzed by chloroperoxidase. Both peroxidatic and catalatic reactions occurred in the reaction system containing H2O2, a reducing substrate, and CPO. A combined reaction mechanism was proposed for CPO-catalyzed reactions in which the modified ping-pong mechanism was applicable for the peroxidatic reactions and the formation of a CPO-I-H2O2 complex occurred for the catalatic reaction.
Catalase↗
Pediatric Salmonella enterocolitis in a teaching hospital in Taitung: A four-year analysis.
In order to understand the childhood Salmonella enterocolitis in Taitung, we retrospectively collected the patients with the diagnosis of acute enterocolitis who were admitted to the pediatric wards of Taitung branch of Mackay Memorial Hospital from January 1, 1995 to December 31, 1998. Salmonella enterocolitis accounted for 16.8% of the total cases of acute enterocolitis. The mean age of the patients was 14.6 +/- 14.1 months old. Seventy-nine patients were male and 78 patients were female. Eighty-two patients lived in the urban area and 75 patients lived in the suburbs. The mean duration from onset of illness to admission was 2.6 +/- 1.9 days. The mean duration of hospitalization was 6.6 +/- 4.8 days. The peak incidence was in August and September. The most common clinical manifestations were fever (74.5%) and blood stool (46.5%). In 157 patients, Salmonella serogroup B was isolated from stool in 115 patients. The rate of bacteremia was 4.5%. Serogroup D accounted for 28.6% of the bacteremia. Two patients developed meningitis and one patient had osteomyelitis. Of 88 patients examined for rotavirus, 12 had positive results. There was neither bowel perforation nor mortality recorded in our study.
Bacteremia↗
[Penicillin-resistant pneumococcal meningitis: report of two cases].
Cases of penicillin-resistant pneumococcal meningitis have been reported in other countries since 1977, but never before reported in Taiwan. In 1990, two cases of the disease were diagnosed here. Case one was a two-year-old boy who had had fever and vomiting for several days prior to admission. Under the impression of meningitis, a spinal tap was done. The CSF yielded pneumococcus, which was misinterpreted as sensitive to penicillin. Penicillin (400,000 units/kg/day) was given parenterally without effect. On the 12th day after admission, another spinal tap still yielded pneumococcus. This time the sensitivity test was reread with great care, and then reported to be penicillin-resistant pneumococcus. Minimal inhibitory concentration (MIC) of penicillin was performed simultaneously and it revealed 0.1 microgram/ml. Vancomycin (60 mg/kg/day) was substituted for penicillin. The patient became afebrile two days later, and was discharged ten days later without sequelae. Case two, a five-month-old girl, was diagnosed to have meningitis because of fever, vomiting, tense fontanel and seizure on admission. After a spinal tap was done, she was put on ampicillin and cefotaxime. The fever subsided two days later. At that time, the CSF was reported to grow pneumococcus, again misread as sensitive to penicillin. The antibiotics was switched to penicillin, but fever recurred. The second spinal tap still yielded pneumococcus which was sensitive to penicillin but resitstant to oxacillin. Based on experience with the first case, penicillin was changed to vancomycin, and performed MIC immediately. The MIC was 1.0 microgram/ml. The patient became afebrile two days later, and was discharged in good condition after ten days of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Child, Preschool↗
Kawasaki disease presenting with disseminated intravascular coagulation: report of one case.
Thrombocytosis is always noted in patients with Kawasaki disease (KD). Here we present a case of KD with an unusual finding of thrombocytopenia. A 3 months old female baby was admitted to our hospital presenting with the classical symptoms and signs of KD. However, initially she also had thrombocytopenia and disseminated intravascular coagulation. She was treated successfully with a single high dose of intravenous immunoglobulin. (2 gm/kg). Thrombocytosis was found on the 10th day of illness, and treatment with low dose aspirin was administered for 3 months. No coronary aneurysm was found on cardiac echography. She was found to be well on a follow-up of 8 months.
Disseminated Intravascular Coagulation↗
Fatal enteroviral infection in a neonate.
Enterovirus infection has been recognized as one of the most common viral infections in the perinatal and neonatal periods. It frequently leads to significant mortality. One fatal case of neonatal enteroviral infection was experienced in last year. The patient was a one-day-old male, presenting with neonatal sepsis. He has a biphasic illness, first with a mild febrile prodrome then followed by severe systemic involvement, with meningitis, myocarditis, hepatosplenomegaly and disseminated intravascular coagulation. All bacterial cultures were negative, but the rectal swab isolated enterovirus. The echocardiogram revealed depressed cardiac function, and he finally expired at the age of 10 days. The autopsy findings supported the diagnosis of perinatal enteroviral infection (coxsackievirus B infection was highly suspected). Clinically, if a neonate presents as sepsis, but has the following conditions, enteroviral infection should be considered: (1) negative bacterial cultures; (2) multiple organ involvement; (3) proven enteroviral infection in the same nursery or ward; (4) a mild febrile illness in the mother within the last antepartum 10 days or the first postpartum 5 days; (5) any family members with fever or signs of upper respiratory infection within 15 days before delivery.
Bacteremia↗