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M D Adams

Publications and source records attributed to M D Adams.

14 recordsLinked to original sources
PubMed1992

Sequence identification of 2,375 human brain genes.

We recently described a new approach for the rapid characterization of expressed genes by partial DNA sequencing to generate 'expressed sequence tags'. From a set of 600 human brain complementary DNA clones, 348 were informative nuclear-encoded messenger RNAs. We have now partially sequenced 2,672 new, independent cDNA clones isolated from four human brain cDNA libraries to generate 2,375 expressed sequence tags to nuclear-encoded genes. These sequences, together with 348 brain expressed sequence tags from our previous study, comprise more than 2,500 new human genes and 870,769 base pairs of DNA sequence. These data represent an approximate doubling of the number of human genes identified by DNA sequencing and may represent as many as 5% of the genes in the human genome.

Brain Chemistry↗
PubMed1992

Chromosomal assignment of 46 brain cDNAs.

Expressed sequence tags (ESTs) have been obtained from several hundred brain cDNAs as an initial effort to characterize expressed brain genes. These ESTs will become tools for human genome mapping and they will also provide candidate causative genes for inherited disorders affecting the central nervous system. We have developed a procedure for the rapid chromosomal assignment of these ESTs: cDNA sequences are first analyzed by a computer program to determine regions likely not to be interrupted by introns in the genomic DNA. A pair of oligonucleotide primers is then designed to amplify this region by the polymerase chain reaction using DNA template from human-rodent somatic cell hybrid chromosomal panels. The chromosomal assignment of the cDNA is determined by studying the segregation of the amplified products in these panels. In this paper we describe the mapping of 46 brain ESTs, as well as observations on the amplification of rodent sequences.

Animals↗
PubMed1992

Caenorhabditis elegans expressed sequence tags identify gene families and potential disease gene homologues.

A database containing mapped partial cDNA sequences from Caenorhabditis elegans will provide a ready starting point for identifying nematode homologues of important human genes and determining their functions in C. elegans. A total of 720 expressed sequence tags (ESTs) have been generated from 585 clones randomly selected from a mixed-stage C. elegans cDNA library. Comparison of these ESTs with sequence databases identified 422 new C. elegans genes, of which 317 are not similar to any sequences in the database. Twenty-six new genes have been mapped by YAC clone hybridization. Members of several gene families, including cuticle collagens, GTP-binding proteins, and RNA helicases were discovered. Many of the new genes are similar to known or potential human disease genes, including CFTR and the LDL receptor.

Amino Acid Sequence↗
PubMed1992

Regulation of the Epstein-Barr virus DNA polymerase gene.

The gene (pol) encoding the Epstein-Barr virus (EBV) DNA polymerase is a member of the "early" class of viral genes which are expressed shortly after activation of latent virus infection. First, mRNA from the EBV-producing cell line, B95-8, treated with 12-O-tetradecanoylphorbol-13-acetate and sodium butyrate to induce lytic replication and expression of this gene was analyzed. Northern (RNA) analysis revealed a message of 3.7 kb found only in induced cells. 5' mapping of pol mRNA by S1 nuclease and primer extension analyses indicates that transcription initiates at tightly clustered sites within a G + C-rich region 126 bp upstream of the open reading frame. The same initiation region was identified in two other EBV-infected cell lines, P3HR1 and Raji, after induction. Second, a 1.29-kb genomic fragment containing this region, when cloned upstream of the chloramphenicol acetyltransferase reporter gene, demonstrated promoter activity in lymphoid cells cotransfected with pEBV-RZ, a genomic expression construct that includes genes for the EBV immediate-early transactivator proteins, BZLF-1 and BRLF-1. Within the upstream 1.29-kb sequence, two regions of 140 bp and 101 bp appear to be needed for promoter activity. These results demonstrate that unlike most EBV genes studied thus far, the pol gene contains multiple transcriptional start sites. The upstream regulatory region of the promoter for the pol gene does not contain canonical promoter elements such as TATA and CAAT boxes and, furthermore, is not constitutively active but requires transactivation by two or more viral proteins.

Amino Acid Sequence↗
PubMed1992

Multipurpose vectors for peptide expression on the M13 viral surface.

We have developed a set of three cloning vectors for the expression of polypeptides on the surface of the M13 viral coat. The M13mp8 genome has been engineered for expression of foreign protein sequences near the NH2-terminus of the mature pIII protein, which is present in five copies on the outside of each M13 viral particle. All three of the vectors carry the same two useful restriction sites for directed cloning of inserts in the pIII coding region; in addition, one vector carries the bacterial gene conferring resistance to the antibiotic tetracycline, and another expresses the lacZ' polypeptide that allows functional complementation of beta-galactosidase activity within the host bacterial cell. All of these vectors propagate well in E. coli DH5 alpha F' cells and do not require helper phage. We demonstrate that a bacteriophage, expressing an eleven amino acid epitope (from human c-myc) at the NH2-terminus of pIII in one of our vectors, can be purified from a vast mixture of other M13 phage through panning techniques. In particular, we find that the c-myc-expressing viral particles can be easily recovered from phage mixtures with the biotinylated form of the monoclonal antibody, 9E10, and streptavidin-coated MagneSphere beads.

Amino Acid Sequence↗
PubMed1991

Secretion of mutant leucine-specific binding proteins with internal deletions in Escherichia coli.

The leucine-specific binding protein, encoded by the livK gene, is located in the periplasm of E. coli. The present study is an attempt to identify intragenic regions that determine the efficiency of its secretion into the periplasm. C-terminal deletions or fusions of the livK gene to trpA (encoding the alpha subunit of tryptophan synthetase) were secreted with little loss of efficiency [1]. A series of deletions was constructed at the unique Sphl site within livK, near the 5' end of the region coding for the mature protein. Between 16 and 113 amino acids were deleted in the amino-terminal one-third of the protein. A few of these deletions were located within a few amino acids of the signal sequence processing site. Deletions extending within thirteen residues of the processing site were processed and secreted more slowly than normal. Secondary structure predictions suggested that the alpha-helical core region of the signal sequence extends into the mature protein in the case of the slow processing mutants, perhaps interfering with the recognition site for leader peptidase or other secretory components. These results suggest that the conformation around the signal processing site may be a critical factor in determining the efficiency of secretion. During the course of this study, it was found that the difference in molecular weight between precursor and mature forms of some binding protein mutants, as judged by SDS-PAGE, was much greater than could be accounted for by processing of the signal sequence. This anomalous mobility on gels, however, could be eliminated by performing SDS-PAGE in the presence of 6 M urea.

Amino Acid Sequence↗
PubMed1977

A cannabinoid with cardiovascular activity but no overt behavioral effects.

Abnormal-delta8-tetrahydrocannabinol (ABN-delta8-THC) failed to elicit central nervous system and cardiovascular effects in laboratory animals. Abnormal-cannabidiol (ABN-CBD) was also devoid of overt behavioral effects but produced marked hypotension with only slight bradycardia in anesthesized dogs.

Animals↗
PubMed1976

Brain 5-hydroxytryptamine correlates of behavior: studies involving spontaneously hypertensive (SHR) and normotensive Wistar rats.

Brain area 5-hydroxytrhptamine (5-HT) turnover and behavioral correlates were compared in spontaneously hypertensive rats (SHR) and normotensive Wistar rats. SHR appeared to have hyperfunctional 5-HT systems as evidenced by the finding that brain area 5-HT turnover times were 53% lower in SHR, with significant changes seen in the limbic forebrain. SHR, while less active upon initial testing of spontaneous motor activity than Wistar rats, did not habituate as readily to the testing procedures as evidenced by higher activity than Wistar rats in repeated testing stiuations. In the light of other data indicating that 5-ht systems are predominantly inhibitory to ongoing behavior, these data suggest that habituation, as determined in this study, is an active process that is retarded in the SHR because of hyperfunctional 5-HT systems. Spontaneous activity of SHR was inhibited less than that of Wistar rats by a conditioned stimulus which is consistent with the observations of others that 5-HT systems tend to suppress responsiveness to external stimuli. While spontaneous activity data suggested that SHR were more emothinal than Wistar rats, the SHR also exhibited a higher avoidance rate in an unsignaled shuttle avoidance procedure which is usually indicative of a lower emotional state.

Animals↗
PubMed1976

Tolerance to the cardiovascular effects of delta9-tetrahydrocannabinol in the rat.

1. Daily intraperitoneal injections of delta9-tetrahydrocannabinol (delta9-THC, 10 mg/kg) resulted in tolerance to the effects of the cannabinoid on body weight and body temperature within 1-2 weeks of treatment. 2. Tolerance failed to develop to the suppression of spontaneous motor activity produced by delta9-THC during 28 days of treatment with the cannabinoid (10 mg/kg, i.p. per day). 3. Following treatment with vehicle for 28 days, intravenous administration of delta9-THC in anaesthetized rats produced a transient pressor response followed by a sustained hypotension and bradycardia. 4. Tolerance to the hypotensive and negative chronotropic responses to intravenous delta9-THC was readily apparent in animals which had received daily intraperitoneal injections of delta9-THC (10 mg/kg) for 28 days. 5. Tolerance failed to develop to the pressor actions of intravenous delta9-THC after 28 days of preptreatment. 6. There was no difference in the pressor response to intravenous noradrenaline in vehicle-treated animals (1.0 ml/kg, i.p., per day for 28 days) and delta9-THC-treated animals (10 mg/kg, i.p., per day for 28 days).

Animals↗
PubMed1976

Characteristics of histamine disposition in vascular smooth muscle.

This study has examined uptake, efflux and metabolism of 14C-histamine by vascular smooth muscle. 14C space in aortae reached 4.3 +/- 0.14 ml/g (mean +/- SE) after 1 h exposure to 14C-histamine (2 muM) in Tyrode's solution. Aminoguanidine (10(-5) M) and non-radioactive histamine (10(-4) and 10(-3) M) significantly reduced 14C space. Efflux experiments were performed on aortic strips exposed to 14C-histamine for 1 h. The rate of loss of radioactivity was not enhanced by nonradioactive histamine or compound 48/80. It appears that 14C-histamine was not accumulated and bound in mast cells in this tissue. After 1 h exposure to 14C-histamine, labeled material was extracted from tissues for identification of metabolites by paper chromatography. About 40% of the label was 14C-histamine, and the remainder was primarily imidazole acetic acid. After exposure to aminoguanidine, an inhibitor of diamine oxidase, about 80% of the label was 14C-histamine. These data suggest that oxidative deamination is the primary catabolic route for histamine in rabbit aorta.

Animals↗
PubMed1976

Vasoconstrictor actions of delta8- and delta9-tetrahydrocannabinol in the rat.

Cardiovascular effects of delta8- and delta9-tetrahydrocannabinol (THC) were studied after systemic intravenous administration and intra-arterial administration into a perfused vascular bed in the urethane-anesthetized rat. Intravenous administration of delta8- and delta9-THC produced dose-related transient increases in blood pressure followed by more prolonged hypotensive responses and bradycardia. Intra-arterial administration of delta8- and delta9-THC into the perfused hindquarters of the rat produced an increase in perfusion pressure indicative of vasoconstriction. The vasoconstrictor response to the cannabinoids corresponded temporally to a similar response produced by i.a. norepinephrine and was in contrast to the more prolonged vasoconstrictor responses produced by vasopressin. Phentolamine, in a dose which reduced the vasoconstrictor effect of norepinephrine by 90%, significantly reduced the response to i.a. delta9-THC while having no effect on the actions of i.a. vasopressin. It was demonstrated that reserpine pretreatment significantly reduced vasoconstrictor actions of i.a. tyramine and delta9-THC but did not alter the responses to norepinephrine. These data suggest that delta8- and delta9-THC have peripheral vasoconstrictor activity in the rat which may be mediated, in part, through a tyramine-like action on adrenergic nerve terminals.

Adrenergic alpha-Antagonists↗