Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.1 (S1 nuclease)
3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Telomeric heterochromatin can be demonstrated in Allium cepa chromosomes when root tip squashes are subjected to a C-banding procedure (treatment with saturated barium hydroxide for 10 min, followed by 1 h in phosphate buffer at 60 degrees C). Acridine orange (A0) staining indicated that the chromosomal DNA was denatured by the alkaline treatment and that it renatured within the first 3-7 min in the hot buffer. The DNA of the telomeres reannealed somewhat faster than the rest of the chromosomal DNA, but the AO staining suggested that all chromosomal DNA was double stranded after 7 min in buffer. Digestion of the chromosomes with a single strand specific nuclease, DNase S1, followed by Feulgen staining, demonstrated that the AO staining gives a somewhat misleading picture of the extent of DNA denaturation and renaturation. The S1 nuclease results showed that the chromosomal DNA was completely denatured by the alkaline treatment, but that a fraction of the DNA reannealed during the deionized water wash that preceded the incubation in hot buffer. Neither controls nor chromosomes subjected to the complete C-banding procedure were affected by S1 nuclease digestion, demonstrating that virtually all of the chromosomal DNA was double stranded both before and after the C-banding process. These results, along with the fact that the appearance of the bands was unaffected when the buffer incubation was performed at high (80 degrees C) or low (40 degrees C) temperature, indicated that differential DNA denaturation and renaturation is unlikely to be responsible for C-banding in this species.
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PMID:Differential rates of DNA denaturation and renaturation in situ in relation to the C-banding of Allium cepa chromosomes. 75 82

We have developed a novel plasmid isolation procedure and have adapted it for use on an automated nucleic acid extraction instrument. The protocol is based on the finding that phenol extraction of a 1 M guanidinium thiocyanate solution at pH 4.5 efficiently removes genomic DNA from the aqueous phase, while supercoiled plasmid DNA is retained in the aqueous phase. S1 nuclease digestion of the removed genomic DNA shows that it has been denatured, which presumably confers solubility in the organic phase. The complete automated protocol for plasmid isolation involves pretreatment of bacterial cells successively with lysozyme, RNase A, and proteinase K. Following these digestions, the solution is extracted twice with a phenol/chloroform/water mixture and once with chloroform. Purified plasmid is then collected by isopropanol precipitation. The purified plasmid is essentially free of genomic DNA, RNA, and protein and is a suitable substrate for DNA sequencing and other applications requiring highly pure supercoiled plasmid.
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PMID:Plasmid purification by phenol extraction from guanidinium thiocyanate solution: development of an automated protocol. 171 49

Expression of tyrosine hydroxylase (TH) in cultured cells of the ventral hypothalamus-midbrain of fetal rats has been investigated. TH mRNA and TH were quantified by an S1 nuclease protection assay and an immunoblot assay, respectively. Dihydroxyphenylalanine (DOPA) and dopamine secretion were evaluated using their rates of accumulation in the culture medium. The rate of accumulation of DOPA was 2-3 times that of dopamine. Inhibitors of TH activity caused a dose-dependent reduction in DOPA secretion. During an 11-week culture of dissociated cells, TH mRNA increased from 1.6 to 2.8 attomole/well between the first and fourth week of culture, remained steady to the ninth week, and then declined. TH increased from 12 to 105 fmol/well between the first and seventh week and then declined. DOPA secretion increased until the sixth week and then remained steady to the tenth week. An extract of rat pituitaries stimulated DOPA secretion by the cultures in a dose-dependent manner. This activity, attributed to a cytotropic factor (CTF), was inactivated by heating for 10 min in a boiling water bath, but was unaffected by trypsin digestion. Incubation with CTF for 24, 48, 72, and 96 h resulted in a day by day increase in the secretion of DOPA. After 96 h of culture with CTF, the amount per well of TH mRNA, but not TH, was significantly (P less than 0.01) greater than the control value. Pituitary CTF is probably not PRL, since rat PRL did not appreciably affect DOPA secretion or the amount of TH mRNA or TH in the cells. Withdrawal of CTF from CTF-stimulated cells resulted in a marked reduction in DOPA secretion as well as a decrease in TH mRNA. These results support the hypothesis that the pituitary gland contains a cytotropic factor that stimulates TH expression in fetal brain cells of the hypothalamus-midbrain.
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PMID:Expression of tyrosine hydroxylase in cultured brain cells: stimulation with an extractable pituitary cytotropic factor. 197 Feb 92

We have recently shown that the octapeptide angiotensin II is a potent stimulus of protein synthesis and growth in cultured cardiomyocytes. The present study was performed to determine if the renin-angiotensin system was involved in regulating cardiac cell growth in vivo. The pressure-overload cardiac hypertrophy model that develops in abdominal aorta-constricted rats was studied. At 7 and 15 days after abdominal aorta constriction, rats developed significant left ventricular hypertrophy. The increase in left ventricular mass was completely prevented in animals fed the angiotensin-converting enzyme inhibitor, enalapril maleate (0.2 mg/ml) in their drinking water. Cardiac afterload was the same in both groups of animals in that carotid artery pressures were not different in conscious awake aortic-constricted animals receiving and not receiving enalapril. These data suggest a direct growth effect of angiotensin II on the left ventricle and indicate a role for the renin-angiotensin system in the cardiac hypertrophy that develops in response to pressure overload. The presence and chamber localization of angiotensinogen mRNA was determined using Northern hybridization and S1 nuclease mapping analysis. Angiotensinogen mRNA, as determined by dot-blot hybridization analysis, was significantly increased in hypertrophied left ventricles at both 7 and 15 days after the surgery, when compared with sham-operated controls. The activity of the circulating renin-angiotensin system, as indexed by plasma renin activity was increased at 1 day following surgery [6.0 +/- 2.0 ng.ml-1.h-1 angiotensin I (control) vs. 41.8 +/- 10.9 ng.ml-1.h-1 angiotensin I (experimental)], but returned to control values by day 3 postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renin-angiotensin system involvement in pressure-overload cardiac hypertrophy in rats. 214 33

Five strains of gliding bacteria were isolated in France from farmed diseased rainbow trouts reared at low water temperature. The resemblance of these bacteria to the known fish pathogen "Cytophaga psychrophila" led to their comparative study with reference strain NCMB 1947 and with an American isolate. Morphological, physiological, and biochemical characteristics of the seven strains proved to be similar. Comparison of their DNA by the S1 nuclease DNA-DNA hybridization method showed that the seven strains formed a tight genomic species with DNA relatedness above 90%. This is the first identification of this fish pathogen in a European country. The main phenotypic characteristics differentiating this bacterium from other nonpathogenic gliding bacteria of fish origin include a poor gliding movement, yellow compact or weakly rhizoid colonies on solid media, and the presence of flexirubin-type pigments. The inability to metabolize any carbohydrates, the strong proteolytic activity, the absence of growth in more than 0.5% NaCl, and the tolerance to a maximum temperature of 25 degrees C are also useful characteristics of this group of bacteria.
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PMID:Phenotypic and genomic studies of "Cytophaga psychrophila" isolated from diseased rainbow trout (Oncorhynchus mykiss) in France. 276 77

Thyroid hormone has a number of effects on cardiovascular and renal function which are shared by the atrial natriuretic peptide (ANP). We attempted to demonstrate a relationship between the two by studying the effects of thyroid hormone on the expression of the ANP gene and the secretion of its encoded protein. Thyroid hormone, when given to thyroidectomized rats, increased plasma ANP levels by approximately 2-fold in both watered and dehydrated animals. Cardiac ANP mRNA in dehydrated animals fell to 25% of that in the water-replete controls. T4 increased cardiac ANP mRNA 3-fold in dehydrated animals, but failed to alter ANP mRNA in those animals allowed free access to water. The effect of thyroid hormone appeared to take place, at least in part, at the level of the ANP-synthesizing cardiocyte. T3, at concentrations ranging from 10(-10)-10(-8) M, increased ANP mRNA levels a maximum of 2-fold in primary cultures of neonatal cardiocytes. Both basal and T3-stimulated ANP transcripts appeared to be identical to their counterparts in the adult atria, as assessed by blot hybridization and S1 nuclease analysis. T3 (10(-8) M) also effected a 2-fold increase in media ANP immunoreactivity. These data indicate that thyroid hormone increases the secretion and genetic expression of ANP in vivo and in vitro and suggests a role for the peptide as a mediator of at least some thyroid hormone effects in the cardiovascular system.
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PMID:Thyroid hormone increases rat atrial natriuretic peptide messenger ribonucleic acid accumulation in vivo and in vitro. 296 52

Exposure of Gambusia affinis to water containing different concentrations of benzo[a]pyrene (BaP) causes an increase in benzo[a]pyrene monooxygenase (BPMO) activity which reaches a maximum on the second day. Concomitantly, the DNA is altered in such a way that nuclease S1-sensitive sites (SSS) become measurable. The size distribution of liver DNA treated with nuclease S1 in control fish shows two populations of DNA by length, with means of 30 X 10(6) and 60 X 10(6) Daltons, respectively. In fish treated with 100 ppb BaP, the population with longer molecules of DNA disappears and shorter molecules increase in number. This may be explained in terms of the introduction of an additional 0.31-0.46 DNA nicks per control DNA molecule caused by metabolically activated BaP derivatives.
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PMID:DNA damage by benzo[a]pyrene in the liver of mosquito fish Gambusia affinis. 299 11

The major light-harvesting complex in eukaryotic red algae and prokaryotic cyanobacteria is the phycobilisome, a water-soluble complex located on the outer surface of the photosynthetic membranes and composed of both pigmented phycobiliproteins (85%) and non-pigmented linker (15%) polypeptides. The phycobiliproteins are encoded by a gene family and exhibit varying degrees of sequence homology (25 to 55%). Some cyanobacteria can maximize the absorption of prevalent wavelengths of light by adjusting the phycobiliprotein composition of the phycobilisome, a process called complementary chromatic adaptation. In the chromatically adapting species Fremyella displosiphon, there are at least two sets of phycocyanin genes; one is transcribed as two red light-induced transcripts and the other is encoded on a single transcript present in both red and green light. We have determined the complete nucleotide sequences of both sets of phycocyanin subunit genes and their associated 5' and 3' regulatory regions. Based on S1 nuclease protection experiments, the transcripts (1600 and 3800 bases) encoding the inducible phycocyanin subunits have the same 5' end, and possible mechanisms for their synthesis are presented. The 5' end of the 1500-base transcript encoding the constitutive phycocyanin subunits was determined and revealed an Escherichia coli-like "-10" and "-35" region, and sequences near the transcription initiation site homologous to the analogous region of the phycocyanin gene set of Anabaena sp. 7120. Determination of the 3' ends of the transcripts encoding both F. diplosiphon phycocyanin gene sets revealed regions of potential secondary structure that may be important for transcription termination and/or transcript stability. In addition, the sequence of an open reading frame (encoding a 30 kDa polypeptide), located 3' to the constitutive phycocyanin gene set in F. diplosiphon and highly conserved in at least three cyanobacterial species, is presented. The same high degree of sequence homology between the two F. diplosiphon PC alpha and PC beta sequences (85 and 77%, respectively) was found at both the nucleotide and amino acid levels, and similar results were obtained for interspecies comparisons. Implications of these homologies with regard to the evolution of phycobiliprotein subunits are discussed.
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PMID:Molecular characterization and evolution of sequences encoding light-harvesting components in the chromatically adapting cyanobacterium Fremyella diplosiphon. 312 91

A collection of 31 strains received as Agrobacterium tumefaciens and A. radiobacter was subjected to detailed phenotypic and genomic studies. These strains were recovered from plants, soil, water and clinical specimens. Type strains of A. tumefaciens, A. radiobacter, A. rhizogenes and A. rubi were also included. The strains were tested for their ability to use 169 organic compounds as sources of carbon and energy. In addition, 11 conventional characters were studied for each strain. Relatedness among the strains was assessed by determining the extent of reassociation in heterologous DNA preparations. S1 nuclease and diethylaminoethyl-cellulose filters were used to separate reassociated from non-reassociated nucleotide sequences, and to determine the thermal stability of related nucleotide sequences. The resultant data revealed the following points: regardless of their phytopathogenic effects, 3-ketolactose-producing A. tumefaciens and A. radiobacter strains group into one species; this species contains 9 taxa which can be differentiated from each other by phenotypic and genomic characters; clinical isolates did not induce tumours on plants and clustered in three taxa of this species; the clinical and ecological significance of these organisms is not known; the present classification of the genus Agrobacterium is based on phytopathogenicity and does not reflect the phylogenetic relationships amongst these bacteria; as proposed previously by several workers, the genus Agrobacterium should be divided into 3 species on the basis of phenotypic and genomic characteristics. Different aspects of the classification and nomenclature of Agrobacterium are discussed.
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PMID:[Taxonomic position of Agrobacterium strains of hospital origin]. 608 9

Nuclease S1 hydrolyzes the Sp-diastereomer of 5'-O-(2'-deoxyadenosyl)-3'-O-thymidyl phosphorothioate in H2(18)O to [18O]deoxyadenosine 5'-O-phosphorothioate which can be phosphorylated enzymatically to the Sp-diastereomer of [alpha-18O]deoxyadenosine 5'-O-(1-thiotriphosphate). 31P nmr spectroscopy shows the oxygen-18 in this compound to be in a nonbridging position at the alpha-phosphorus, indicating that the hydrolysis reaction catalyzed by nuclease S1 proceeds with inversion of configuration at phosphorus. This result is compatible with a direct nucleophilic attack of H2O at phosphorus without the involvement of a covalent enzyme intermediate.
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PMID:Stereochemical course of DNA hydrolysis by nuclease S1. 629 10


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