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31.
M Smith S Smalley R Cantor M Pandolfo M I Gomez R Baumann P Flodman K Yoshiyama Y Nakamura C Julier 《Genomics》1990,6(1):105-114
Tuberous sclerosis (TSC) is a dominantly inherited disorder characterized by hamartomas and hamartias in one or more organs, most often in skin, brain, and kidneys. Analysis of the basic genetic defect in tuberous sclerosis would be greatly expedited by definitive determination of the chromosomal location of the TSC gene or genes. We have carried out genetic linkage studies in 15 TSC families, using 34 polymorphic markers including protein markers and DNA markers. Pairwise lod scores were calculated using LIPED, and multipoint analyses were carried out using MENDEL. In the pairwise linkage analysis, using a penetrance value of 90%, a significant positive lod score was obtained with MCT128.1 (D11S144), 11q22-11q23, Zmax 3.26 at theta = 0.08. The tyrosinase probe TYR (11q14-11q22) gave a maximum lod score of 2.88 at theta = 0. In the multipoint analyses the most likely order is (TYR,TSC)-MCT128.1-HHH172. Homogeneity analysis was carried out using the USERM9 subprogram of MENDEL, which conducts the admixture test of C. Smith (1963, Ann. Hum. Genet. 27: 175-182). This test provided no evidence for genetic heterogeneity (that is, non-11-linked families) in this data set. 相似文献
32.
We have studied the mechanisms of breakdown of 2'-5' oligoadenylates. We monitored the time-courses of degradation of ppp(A2'p5')nA (dimer to tetramer) and of 5'OH-(A2'p5')nA (dimer to pentamer) in unfractionated L1210 cell extract. The 5' triphosphorylated 2'-5' oligoadenylates are converted by a phosphatase activity. However, 2'-5' oligoadenylates are degraded mainly by phosphodiesterase activity which splits the 2'-5' phosphodiester bond sequentially at the 2' end to yield 5' AMP and one-unit-shorter oligomers. The nonlinear least-squares curve-fitting program CONSAM was used to fit these kinetics and to determine the degradation rate constant of each oligomer. Trimers and tetramers, whether 5' triphosphorylated or not, are degraded at the same rate, whereas 5' triphosphorylated dimer is rapidly hydrolyzed and 5'-OH dimer is the most stable oligomer. The interaction between degradation enzymes and the substrate strongly depends on the presence of a 5' phosphate group in the vicinity of the phosphodiester bond to be hydrolyzed; indeed, when this 5' phosphate group is present, as in pp/pA2'p5'A/or A2'/p5'A2'p5'A/, affinity is high and maximal velocity is low. Such a degradation pattern can control the concentration of 2'-5' oligoadenylates active on RNAse L either by limiting their synthesis (5' triphosphorylated dimer is the primer necessary for the formation of longer oligomers) and/or by converting them into inhibitory (e.g., monophosphorylated trimer) or inactive (e.g., nonphosphorylated oligomers) molecules. 相似文献
33.
34.
P. Badia A. Lorenzo T. Gomez A. Bolaños 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,157(6):865-871
Summary Ion transport processes in the ileum of the lizard,Gallotia (=Lacerta) galloti was examined in vitro by measuring Na22 and Cl36 fluxes across short-circuited preparations.In Ringer-bicarbonate solution there was both a net sodium flux (
) and a net chloride flux (
) from mucosa to serosa. The inequality between
and short-circuit current (I
sc) suggests that part of the net sodium transport is the result of an electrically neutral transport mechanism or that another electrogenic mechanism opposite in sign is contributing to the short-circuit current.In the absence of sodium, the short-circuit current and net chloride flux were abolished. In the absence of chloride, the net sodium was reduced but not abolished and the short-circuit current was unchanged.From an analysis of the effects of the inhibitors furosemide, amiloride, disulfonic stilbene (DIDS) and acetazolamide, a plausible model was developed to explain the characteristics of these transports. It is proposed that the entry of sodium into the cell across the luminal membrane occurs by two pathways. Part occurs by the antiport Na+H+ and part by an electrogenic pathway. The entry of chloride is by the antiport Cl–HCO
3
–
.Symbols and abbreviations
DIDS 4,4
diisothiocyanatostilbene-2,2-disulfonic acid
-
G
t
tissue conductance
-
I
sc
short circuit current
-
m
mucosal
-
PD
potential difference
-
s
serosal 相似文献
35.
G H Greeley Y S Guo G Gomez F Lluis P Singh J C Thompson 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1988,189(3):325-328
The purpose of this study was to determine whether the inhibitory action of peptide YY (PYY) on gastric acid secretion is attributable to the release of gastric somatostatin in rats. Two groups of rats (six rats/group) were anesthetized with urethane and prepared with gastric fistulas and jugular catheters. Pentagastrin (18 micrograms/kg-h) was given intravenously for 150 min to stimulate gastric acid secretion. Intravenous PYY (130 micrograms/kg-h) inhibited pentagastrin-stimulated gastric acid secretion significantly (P less than 0.05). Administration of iv PYY resulted in a 41% reduction (P less than 0.05) in pentagastrin-stimulated gastric acid secretion. In another group of anesthetized rats, administration of PYY (10(-7), 10(-8) M) failed to stimulate a release of somatostatin from the isolated-perfused rat stomach. Our findings indicate that PYY can inhibit gastric acid secretion independently of release of gastric somatostatin in the rat. 相似文献
36.
T Gomez R Rial A Bola?os M Molina 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1988,90(1):203-205
1. Lizards Gallotia galloti received daily 3 mg/kg body wt of diphenylhidantoin (DPH) over a period of 15 days and at the same time the animals were kindled. 2. The progression of the kindling effect was evaluated by counting the number of spontaneous epileptiform potentials, the duration of afterdischarges and the duration of electroencephalographic spontaneous seizures. 3. The diphenylhidantoin treated group, relative to controls presented: (a) significant reduction in the duration of afterdischarges and spontaneous electroencephalographic seizures; and (b) increased frequency of the spontaneous epileptiform potentials. 相似文献
37.
M. Scuteri M. A. Sala de Miguel J. Blanco Viera E. Planes de Banchero 《Mycopathologia》1992,120(3):177-182
Seventeen strains of Penicillium spp. have been isolated from Poa huecu Parodi from the Zapala zone, exhibiting toxicity to sheet. The following strains have been identified: P. crustosum, cyclopium, notatum, palitans, puberulum, verrucosum, viridicatum and Penicillium spp. The toxigenic capacity of the strains was studied after growing them under suitable conditions. Toxins produced were analysed by thin layer chromatography (TLC). Penitrem A (PA) and Penitrem B (PB) neurotoxins were identified and quantitated in twelve strains; verruculogen (VERR) and fumitremorgen B (FTB) being present in one of them. The effect of these mycotoxins was studied in mice. Neurological symptoms characteristic of the intoxication by tremorgenic toxins and similar to those observed in sheep suffering from huecu's disease were observed. The possible role of these toxins as causative agents of huecu's disease is discussed. 相似文献
38.
Cryptosporidium-specific circulating antigens were detected in sera of experimentally infected calves and AIDS patients by an enzyme-linked immunosorbent assay. Antigenemia was detectable from 2 to a minimum of 22 days post-infection (d.p.i.) in calves whose feces were parasitologically positive from 2-10 d.p.i. Antigenemia was detected in AIDS patients showing no a sero-conversion to immunoglobulin (Ig) M or to IgG. The detection of circulating antigens in humans allows early diagnosis of cryptosporidiosis, even in immunosuppressed patients. 相似文献
39.
M. Rosario Rodicio Miguel A. Alvarez Keith F. Chater 《Molecular & general genetics : MGG》1991,225(1):142-147
Summary IS112
is a transposable element identified in Streptomyces albus G by its frequent mutagenic insertion into the genes for the SalI restriction-modification system. IS112 is present in several copies in the genome of S. albus G. Homologous sequences were detected in other Streptomyces strains. Sequence analysis revealed that IS112 has a length of 883 by with a GC content of 67.4%. The copy that was isolated contained imperfect inverted repeats (16/20 match) at its ends and was flanked by a 2 by duplication at the target site, which was located within the gene (salIR) for the Sall endonuclease. A long open reading frame (ORF) encoding a putative polypeptide of 256-253 amino acids spans almost the entire sequence. Significant homology was detected between this polypeptide and that corresponding to ORFB of IS493, an insertion sequence recently isolated from Streptomyces lividans 66.
相似文献
相似文献
40.
The four major components of the wheat monomeric α-amylase inhibitors (WMAI) from wheat, Triticum aestivum, endosperm have been isolated and characterized. Two of them, WMAI-1 and WMAI-2, are highly active against the α-amylase from the insect Tenebrio molitor and their N-terminal amino acid sequences indicate that they are closely related to each other (86% identical residues) and to the other members of the family (subunits of dimeric and tetrameric α-amylase inhibitors and trypsin inhibitors). WMAI-1, which is identical to the previously described 0.28 inhibitor, is encoded by a gene located in the short arm of chromosome 6D and WMAI-2 by a gene in the short arm of chromosome 6B. Components 3 and 4, which have blocked N-terminal residues, have identical internal amino acid sequences and are a separate class of proteins with respect to WMAI-1 and WMAI-2, although their amino acid composition and apparent molecular weights are quite similar. Their inhibitory activity versus α-amylases is either unstable during the purification process or due to contamination with other inhibitors. 相似文献