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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We present evidence that the expression of rho is regulated by rho-dependent attenuation of transcription. Gene fusion analysis with nested series of deletions of rho indicated that the transcription of rho is attenuated in a rho-dependent manner in the leader region and that neither a read-through transcription from the upstream gene, trxA, nor a modulation of transcription initiation of the rho promoter is involved in the self-control of rho. S1 mapping and Northern hybridization analyses localized at least six transcription attenuation or termination sites in the region ranging from the 3' end of the trxA structural gene to the middle of the rho structural gene. Among them, the most upstream site overlapping the rho promoter sequence was assigned to the terminator for the trxA gene, and the second and third sites, mapping about 80 and 50 nucleotides upstream from the start codon of rho, were suggested to function as the major attenuation sites for regulation of the rho expression. Further, the start points of the trxA and rho RNAs were determined in an in vitro transcription system to be located 111 nucleotides (U) and 255 nucleotides (G) upstream from their respective start codons. These results necessitate revisions of previous predictions on the sites of transcriptional signals in the trxA and rho genes (S. Brown, B. Albrechtsen, S. Pedersen, and P. Klemm, J. Mol. Biol. 162:283-298, 1982; C.-J. Lim, D. Geraghty, and J. A. Fuchs, J. Bacteriol. 163:311-316, 1985; B.J. Wallace and S.R. Kushner, Gene 32:399-408, 1984).
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PMID:Autogenous regulation of the gene for transcription termination factor rho in Escherichia coli: localization and function of its attenuators. 242 5

Previous publications on the National Toxicology Program (NTP)-sponsored mutagenicity testing program in Drosophila dealt with evaluations of chemicals following adult treatment (feed, injection). The current paper deals with a comparison between the laboratories at Brown University (BRU) and the University of Wisconsin at Madison (UWM) regarding the response of larvae to treatment with chemicals in the sex-linked recessive lethal (SLRL) test and, where appropriate, the reciprocal translocation test as well. Dimethylnitrosamine (DMN) and dimethylbenz(a)anthracene were used first as reference mutagens. Six coded compounds were then evaluated regarding their repeatability in the two laboratories; the compounds were benzo(a)pyrene, 3-methylcholanthrene, coumarin, quinoline, formaldehyde, and 9-aminoacridine. It was concluded that at this time it would be imprudent to forgo larval treatment in cases where compounds proved negative after adult feeding. Accordingly, testing a series of 20 compounds negative after adult treatment is in progress.
Environ Mol Mutagen 1989
PMID:Chemical mutagenesis testing in Drosophila. VI. Interlaboratory comparison of mutagenicity tests after treatment of larvae. 251 Oct 11

Immune complexes occur spontaneously in the testis of Brown-Norway (BN) inbred rats between the basal lamina of the seminiferous tubules and the outer lamina of the myoid testicular cells. The deposits can be detected immunohistologically (IgG; C3) and by electron microscopy. The immune complexes appear between the 8th and 12th weeks of life, increase in amount up to the 30th week and decrease thereafter. After about the 20th week, of life, 15% of the animals show destruction of the germinal epithelium accompanied by an infiltration of lymphocytes and plasma cells. The final stage of this disease, which initially shows no signs of inflammation, is characterized by diffuse tubular atrophy. However, up to the 70th week of life, 85% of the animals with immune complexes show no pathological alterations. Antibodies eluated from the testes react with spermatocytes I and structures close to the lumen of the seminiferous tubules, but not with mature sperms. Serum antibodies to sperms occur in about 25% of the BN rats, but the presence of these antibodies shows no correlation with the immunohistological findings. This newly described spontaneous immune complex orchitis is regarded as a further example of an in-situ-induced immune complex disease. The observations made here can be compared with those in (peri-) membraneous glomerulonephritis, another example of a disorder resulting from in-situ-formation of immune deposits.
Virchows Arch B Cell Pathol Incl Mol Pathol 1989
PMID:Spontaneous immune complex orchitis in brown Norway rats. 256 48

Previous studies indicated that activation of alpha 1-adrenergic receptors in BC3H-1 muscle cells (S. K. Ambler and P. Taylor, J. Biol. Chem. 261:5866-5871, 1986) and muscarinic receptors in 1321N1 astrocytoma cells (S. B. Masters, T. K. Harden, and J. H. Brown, Mol. Pharmacol. 27:325-332, 1985) resulted in the rapid mobilization of Ca2+ from internal stores of both cell types. Paradoxically, alpha 1-adrenergic agonists did not rapidly increase inositol trisphosphate (Ins-P3) formation in BC3H-1 cells, in distinction to the rapid increase in Ins-P3 accumulation observed in 1321N1 cells after muscarinic stimulation. To determine whether the variations observed in the Ins-P3 response could be ascribed to differences in the relative amounts of inositol 1,4,5-trisphosphate, inositol 1,3,4-trisphosphate, and inositol tetrakisphosphate (respectively, Ins-1,4,5-P3, Ins-1,3,4-P3, and Ins-P4), we have separated the individual inositol phosphates by high-performance liquid chromatography and examined the rates of conversion of individual inositol phosphates in the two types of cells. Muscarinic stimulation of 1321N1 cells resulted in increased Ins-1,4,5-P3 production, as well as the rapid production of Ins-1,3,4-P3 and Ins-P4. Application of alpha 1-agonist to BC3H-1 cells produced a modest but delayed increase in accumulation of Ins-1,4,5-P3. Adrenergic stimulation also resulted in a smaller and even slower production of Ins-1,3,4-P3, and Ins-P4 could not be detected in BC3H-1 cells under any conditions employed. Thus, over a 30-sec interval in which Ca2+ is mobilized to a maximum extent, increases in Ins-1,4,5-P3, Ins-1,3,4-P3, or Ins-P4 amounted to less than 10% over basal values in BC3H-1 cells. These results indicate that the regulation of Ins-P3 isomer formation and conversion may vary substantially between different cell types. In addition, if inositol 1,4,5-trisphosphate is the sole mediator of intracellular Ca2+ release, it is necessary to propose that an increase in Ins-1,4,5-P3 sufficient to mobilize Ca2+ rapidly may occur only within discrete cellular localities in some cell types. According, it may not be possible to detect the increases in Ins-1,4,5-P3 over basal concentrations when measuring total cellular inositol phosphates.
Mol Pharmacol 1987 Sep
PMID:Receptor-mediated inositol phosphate formation in relation to calcium mobilization: a comparison of two cell lines. 282 90

The fate of the black thyroid induced by minocycline treatment (100 mg/kg daily for 21 days) in the rat was studied by light and electron microscopy after 6 months. The black discoloration of the thyroid gland remained and numerous dense bodies containing highly electron-dense deposits were seen in most of the follicular epithelial cells. It appears that the turnover rate of follicular epithelial cells is very low and the electron-dense deposits are largely retained, though debris derived from degenerate follicular epithelial cells containing the dense deposits may be phagocytosed by macrophage-like cells in the interfollicular connective tissue. Brown-black granules are also found in the extremely attenuated follicular epithelial cells of cold follicles.
Virchows Arch B Cell Pathol Incl Mol Pathol 1986
PMID:Fine structural aspects on the fate of rat black thyroids induced by minocycline. 287 53

Statistical methods for computing the standard errors of the branching points of an evolutionary tree are developed. These methods are for the unweighted pair-group method-determined (UPGMA) trees reconstructed from molecular data such as amino acid sequences, nucleotide sequences, restriction-sites data, and electrophoretic distances. They were applied to data for the human, chimpanzee, gorilla, orangutan, and gibbon species. Among the four different sets of data used, DNA sequences for an 895-nucleotide segment of mitochondrial DNA (Brown et al. 1982) gave the most reliable tree, whereas electrophoretic data (Bruce and Ayala 1979) gave the least reliable one. The DNA sequence data suggested that the chimpanzee is the closest and that the gorilla is the next closest to the human species. The orangutan and gibbon are more distantly related to man than is the gorilla. This topology of the tree is in agreement with that for the tree obtained from chromosomal studies and DNA-hybridization experiments. However, the difference between the branching point for the human and the chimpanzee species and that for the gorilla species and the human-chimpanzee group is not statistically significant. In addition to this analysis, various factors that affect the accuracy of an estimated tree are discussed.
Mol Biol Evol 1985 Jan
PMID:Methods for computing the standard errors of branching points in an evolutionary tree and their application to molecular data from humans and apes. 289 60

Line of Brown leghorn chickens free of RAV-O-type endogenous proviruses was obtained by selection under blot hybridization control. A set of dispersed sequences distantly related to avian leukosis virus genome was found in DNA of these chickens by means of hybridization in non-stringent conditions. Different restriction fragments were detected by gag, pol and env hybridization probes.
Mol Gen Mikrobiol Virusol 1987 Mar
PMID:[The genome of chickens free of endogenous avian leukosis-sarcoma proviruses contains sequences distantly related to Rous sarcoma virus]. 303 85

DNA encoding an antigen of 101,000 apparent molecular weight from the human malaria parasite Plasmodium falciparum was cloned and sequenced. Genomic DNA from the Camp strain covering the complete coding region along with cDNA from the FCR3 strain covering 81% of the coding region were obtained. The cloned DNA specified a full-length protein of 743 amino acids which included two tandemly repeated regions, one near the amino terminus containing eight hexapeptide repeats of sequence TVNDEDED, and the second near the carboxyl terminus containing primarily KE and KEE repeats. The latter repeated region is encoded by a 174-base stretch of mRNA containing only a single pyrimidine. Except for a putative leader sequence located at the amino terminus of the protein, the protein is hydrophilic and highly charged with a calculated isoelectric point of 5.6. Sequences from the Camp and FCR3 strains are very close and are also nearly identical to the partial cDNA sequence of the acidic basic repeated antigen (ABRA) protein from the FC27 strain (Stahl, H.D., Bianco, A.E., Crewther, R.F., Anders, R.F., Kyne, A.P., Coppel, R. L., Mitchell, G.F., Kemp, D.J., and Brown, G.V. (1986) Mol. Biol. Med. 3, 351-368). ABRA was previously shown to be located at the merozoite surface and in the parasitophorous vacuole. Because of its location and because it becomes complexed to merozoites when schizonts rupture in the presence of immune serum, ABRA is a candidate component of a malaria vaccine.
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PMID:Primary structure of a Plasmodium falciparum malaria antigen located at the merozoite surface and within the parasitophorous vacuole. 304 68

A mathematical theory for computing the probabilities of various nucleotide configurations among related species is developed, and the probability of obtaining the correct tree (topology) from nucleotide sequence data is evaluated using models of evolutionary trees that are close to the tree of mitochondrial DNAs from human, chimpanzee, gorilla, orangutan, and gibbon. Special attention is given to the number of nucleotides required to resolve the branching order among the three most closely related organisms (human, chimpanzee, and gorilla). If the extent of DNA divergence is close to that obtained by Brown et al. for mitochondrial DNA and if sequence data are available only for the three most closely related organisms, the number of nucleotides (m*) required to obtain the correct tree with a probability of 95% is about 4700. If sequence data for two outgroup species (orangutan and gibbon) are available, m* becomes about 2600-2700 when the transformed distance, distance-Wagner, maximum parsimony, or compatibility method is used. In the unweighted pair-group method, m* is not affected by the availability of data from outgroup species. When these five different tree-making methods, as well as Fitch and Margoliash's method, are applied to the mitochondrial DNA data (1834 bp) obtained by Brown et al. and by Hixson and Brown, they all give the same phylogenetic tree, in which human and chimpanzee are most closely related. However, the trees considered here are "gene trees," and to obtain the correct "species tree," sequence data for several independent loci must be used.
J Mol Evol 1986
PMID:The number of nucleotides required to determine the branching order of three species, with special reference to the human-chimpanzee-gorilla divergence. 310 15

The maximum likelihood (ML) method for constructing phylogenetic trees (both rooted and unrooted trees) from DNA sequence data was studied. Although there is some theoretical problem in the comparison of ML values conditional for each topology, it is possible to make a heuristic argument to justify the method. Based on this argument, a new algorithm for estimating the ML tree is presented. It is shown that under the assumption of a constant rate of evolution, the ML method and UPGMA always give the same rooted tree for the case of three operational taxonomic units (OTUs). This also seems to hold approximately for the case with four OTUs. When we consider unrooted trees with the assumption of a varying rate of nucleotide substitution, the efficiency of the ML method in obtaining the correct tree is similar to those of the maximum parsimony method and distance methods. The ML method was applied to Brown et al.'s data, and the tree topology obtained was the same as that found by the maximum parsimony method, but it was different from those obtained by distance methods.
J Mol Evol 1988
PMID:Property and efficiency of the maximum likelihood method for molecular phylogeny. 190


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