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Biomedical subjects

J Moss

Publications and source records attributed to J Moss.

At least 361 records · Page 20Linked to original sources
PubMed1989

Molecular cloning, characterization, and expression of human ADP-ribosylation factors: two guanine nucleotide-dependent activators of cholera toxin.

ADP-ribosylation factors (ARFs) are small guanine nucleotide-binding proteins that enhance the enzymatic activities of cholera toxin. Two ARF cDNAs, ARF1 and ARF3, were cloned from a human cerebellum library. Based on deduced amino acid sequences and patterns of hybridization of cDNA and oligonucleotide probes with mammalian brain poly(A)+ RNA, human ARF1 is the homologue of bovine ARF1. Human ARF3, which differs from bovine ARF1 and bovine ARF2, appears to represent a newly identified third type of ARF. Hybridization patterns of human ARF cDNA and clone-specific oligonucleotides with poly(A)+ RNA are consistent with the presence of at least two, and perhaps four, separate ARF messages in human brain. In vitro translation of ARF1, ARF2, and ARF3 produced proteins that behaved, by SDS/PAGE, similar to a purified soluble brain ARF. Deduced amino acid sequences of human ARF1 and ARF3 contain regions, similar to those in other G proteins, that are believed to be involved in GTP binding and hydrolysis. ARFs also exhibit a modest degree of homology with a bovine phospholipase C. The observations reported here support the conclusion that the ARFs are members of a multigene family of small guanine nucleotide-binding proteins. Definition of the regulation of ARF mRNAs and of function(s) of recombinant ARF proteins will aid in the elucidation of the physiologic role(s) of ARFs.

ADP-Ribosylation Factors↗
PubMed1989

Isolation and immunological properties of adenosine kinase.

Bovine liver adenosine kinase is a 43 kDa protein that catalyzes the transfer of phosphate from GTP or ATP to adenosine. Its immunological properties were compared to other GTP-binding proteins of approximately 40 kDa, in particular those involved in signal transduction, such as Gs and Gi, the stimulatory and inhibitory regulatory proteins of adenylyl cyclase, Gt, from the visual excitation system, and Go, a similar protein of unknown function. Antibodies elicited in rabbits against adenosine kinase did not significantly cross-react with other guanyl nucleotide-binding proteins. Antibodies against the other GTP-binding proteins did not react with adenosine kinase. Thus these GTP-binding proteins do not exhibit immunological cross-reactivity.

Adenosine Kinase↗
PubMed1989

PAF-induced contraction of canine trachea mediated by 5-hydroxytryptamine in vivo.

We studied the secretory correlates of tracheal smooth muscle contraction caused by platelet-activating factor (PAF) in nine mongrel dogs in vivo. In five dogs, dose-response curves were generated by rapid intra-arterial injection of 10(-10) to 10(-6) mol PAF into the isolated tracheal circulation; tracheal contractile response was measured isometrically in situ. To examine the mechanism by which PAF elicits contraction of canine trachealis, concentrations of serotonin (5-HT) and histamine were assayed in the venous effluent as the arteriovenous difference (AVd) in mediator concentration across the airway for each level of contraction. PAF caused dose-related active tracheal tension to a maximum of 37.2 +/- 5.4 g/cm (10(-6) mol PAF). The AVd in 5-HT increased linearly from 0.20 +/- 0.05 (10(-9) mol PAF) to 3.5 +/- 0.3 ng/ml (10(-6) mol PAF) (P less than 0.005). In contrast, the AVd in histamine was insignificant and did not change with increasing doses of PAF. A positive correlation was obtained between the AVd in 5-HT and active tracheal tension (r = 0.92, P less than 0.001); there was no correlation between AVd in histamine and active tension (r = -0.16). PAF-induced parasympathetic activation was not mediated by 5-HT; contraction elicited by exogenous 5-HT was not affected by muscarinic blockade. We conclude that nonparasympathetically mediated contraction elicited acutely by PAF in dogs results at least in part from secondary release of serotonin and is not mediated by histamine.

Animals↗
PubMed1989

Vascular complications of shotgun injury to the face.

This is a case report of a 23-year-old female who received a gunshot wound to the face while working at a convenience store. Her injuries were: a large left facial entrance wound with a single sinus cavity that was converted from destruction of the paranasal sinuses, a right Collet-Sicard syndrome, and a right vertebral artery pseudoaneurysm at the C1 level. The successful treatment of her injuries is described, with an extensive discussion of the pseudoaneurysm, which was treated endovascularly, with permanent occlusion of the vertebral artery by use of a balloon catheter.

Adult↗
PubMed1988

Mechanism of inhibition of transducin guanosine triphosphatase activity by vanadate.

The visual excitation system of the retinal rod outer segments and the hormone-sensitive adenylate cyclase complex are regulated through guanine nucleotide-binding proteins, transducin in the former and inhibitory and stimulatory regulatory components, Gi and Gs, in the latter. These proteins are functionally and structurally similar; all are heterotrimers composed of alpha, beta, and gamma subunits and exhibit guanosine triphosphatase activity stimulated by light-activated rhodopsin or the agonist-receptor complex. Adenylate cyclase can be stimulated by vanadate, which, like NaF, probably acts through Gs. Effects of vanadate on the function of a guanine nucleotide-binding protein were investigated in a reconstituted model system consisting of purified transducin subunits (T alpha, T beta gamma) and rhodopsin in phosphatidylcholine vesicles. Vanadate (decameric) inhibited [3H]GTP binding to T alpha and noncompetitively inhibited GTP hydrolysis in a concentration-dependent manner with maximal inhibition of approximately 90% at 3-5 mM. Vanadate also inhibited release of bound GDP but did not affect the rate of hydrolysis of bound GTP (single turnover rate), indicating that vanadate did not interfere with the intrinsic GTPase activity of T alpha. Binding of T alpha to rhodopsin and the ADP-ribosylation of T alpha by pertussis toxin, both of which are enhanced in the presence of T beta gamma, were inhibited by vanadate. These findings are consistent with the conclusion that vanadate can cause the dissociation of T alpha from T beta gamma, resulting in the inhibition of GDP-GTP exchange and thereby GTP hydrolysis. Adenylate cyclase activation could result from a similar effect of vanadate on Gs.

Adenylate Cyclase Toxin↗
PubMed1988

Tumor necrosis factor alpha induces early morphologic and metabolic alterations in Friend leukemia cell tumors and fibrosarcomas in mice.

Morphologic and metabolic studies have been carried out on Friend leukemia cell (FLC) tumors (grown in DBA/2 mice) or fibrosarcomas (grown in C3H/HeN or C3H/HeJ mice) shortly after peritumoral injection of recombinant mouse tumor necrosis factor (TNF) alpha. Marked vascular congestion and focal extravasation of erythrocytes were observed as soon as 1 hr after injection of either FLC tumors or fibrosarcomas with TNF. Focal areas of disaggregation of tumor cells were observed 1 hr after injection of TNF. Intraluminal thrombi (composed of degranulated platelets and fibrin) were detected 3 and 6 hr after TNF treatment, and were associated with areas of depletion of endothelial cell cytoplasm. To correlate these morphologic changes in the tumor with alterations in tumor metabolism, NMR spectroscopy and biochemical studies were undertaken on freshly dissected FLC tumors and fibrosarcomas shortly after injection of TNF. The earliest metabolic alterations observed after 1 hr in TNF-treated FLC tumors of fibrosarcomas were: (i) increase in the average intratumoral pH; (ii) decrease in the levels of ATP. These phenomena were not associated with a reduced glycolytic capacity of TNF-treated tumors as, at these early times after injection, the levels of lactic acid were virtually the same for TNF-treated or control treated tumors. Alterations in the levels of some products of phospholipid degradation (GroPCho, GroPEtn, GroP and Cho) also occurred in these tumors as early as 3 hr after TNF treatment. These metabolic changes were not observed in ascitic FLC tumors after TNF treatment. We suggest that TNF induces alterations in tumor blood vessels which subsequently lead to changes in tumor metabolism and tumor degeneration.

Adenosine Triphosphate↗
PubMed1988

Purification and characterization of ADP-ribosylarginine hydrolase from turkey erythrocytes.

ADP-ribosylation of arginine appears to be a reversible modification of proteins with NAD: arginine ADP-ribosyltransferases and ADP-ribosylarginine hydrolases catalyzing the opposing arms of the ADP-ribosylation cycle. ADP-ribosylarginine hydrolases have been purified extensively (greater than 90%) (150,000-250,000-fold) from the soluble fraction of turkey erythrocytes by DE-52, phenyl-Sepharose, hydroxylapatite, Ultrogel AcA 54, and Mono Q chromatography. Mobilities of the hydrolase on gel permeation columns and on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions are consistent with an active monomeric species of approximately 39 kDa. Insertion of an organomercurial agarose chromatographic step prior to Ultrogel AcA 54 resulted in the isolation of a hydrolase exhibiting approximately 35-fold greater sensitivity to dithiothreitol (Ka,sensitive = 41 +/- 16.7 microM, n = 4; Ka,resistant = 1.44 +/- 0.12 mM, n = 3). A similar dithiothreitol-sensitive hydrolase was generated by exposure of the purified resistant enzyme to HgCl2. At 30 degrees C, both thiol-sensitive (HS) and thiol-resistant (HR) hydrolases were relatively resistant to N-ethylmaleimide (NEM); incubation with dithiothreitol prior to NEM resulted in complete inactivation. Both HS and HR required Mg2+ and thiol for enzymatic activity. Mg2+ stabilized both HS and HR against thermal inactivation in the absence and presence of thiol. A purified NAD:arginine ADP-ribosyltransferase, in the presence of NAD, inactivated both HS and HR; Mg2+ and to a greater extent Mg2+ plus dithiothreitol protected both HS and HR from NAD- and transferase-dependent inactivation. Thus, activation of the hydrolase enhanced its resistance to inactivation by transferase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate Ribose↗
PubMed1988

Selective probing of ADP-ribosylation reactions with oxidized 2'-deoxy-nicotinamide adenine dinucleotide.

A homogeneous preparation of an arginine-specific mono(ADP-ribosyl)transferase from turkey erythrocytes effectively utilized 2'-deoxy-NAD+ for the 2'-deoxy(ADP-ribose) modification of arginine methyl ester with an apparent Km of 27.2 microM and a Vmax of 36.4 mumol min-1 (mg of protein)-1. The adduct formed was also used as a substrate by an avian erythrocyte arginine(ADP-ribose)-specific hydrolase that generated free 2'-deoxy(ADP-ribose). In contrast, 2'-deoxy-NAD+ was not a substrate in the initiation or elongation reaction catalyzed by highly purified poly(ADP-ribose) polymerase from calf thymus. However, 2'-deoxy-NAD+ was a potent noncompetitive inhibitor of NAD+ in the elongation reaction catalyzed by the polymerase, with an apparent Ki of 32 microM. These results indicate that 2'-deoxy-NAD+ may be utilized to specifically identify protein acceptors for endogenous mono(ADP-ribosyl)transferases in complex biological systems that may contain a high activity of poly(ADP-ribose) polymerase, i.e., cell nuclei preparations.

ADP Ribose Transferases↗
PubMed1988

Separation of the 24 kDa substrate for botulinum C3 ADP-ribosyltransferase and the cholera toxin ADP-ribosylation factor.

Botulinum C3 ADP-ribosyltransferase modifies a approximately 24 kDa membrane protein believed to bind guanine nucleotides. Cholera toxin ADP-ribosylation factors are approximately 19 kDa GTP-binding proteins that directly activate the toxin. To evaluate a possible relationship between C3 ADP-ribosyltransferase substrate and ADP-ribosylation factor, they were partially purified from bovine brain. ADP-ribosylation factor, but not C3 ADP-ribosyltransferase substrate, stimulated auto-ADP-ribosylation of the choleragen A1 subunit whereas C3 ADP-ribosyltransferase substrate, but not ADP-ribosylation factor, was ADP-ribosylated by C3 ADP-ribosyltransferase. Thus, although both may be GTP-binding proteins, no functional similarity between ADP-ribosylation factor and C3 ADP-ribosyltransferase substrate was found.

ADP Ribose Transferases↗
PubMed1988

Identification of antigens and antibodies specific for Pneumocystis carinii.

To increase understanding of Pneumocystis carinii and its interaction with its hosts, Ag specific for rodent and human P. carinii were identified by the immunoblot method after PAGE of P. carinii organism extracts. The m.w. of the major Ag of rat P. carinii were 45,000, 110,000, and a broad band of 49,000 to 64,000, and of human P. carinii were 22,000, 24,000, and a broad band of 35,000 to 45,000 daltons. Human and rat pneumocystis were not antigenically identical. Specific antibodies against rat P. carinii Ag were found in 18 of 79 rats by the immunoblot method. Specific antibodies against human P. carinii Ag were found in 32 of 33 adult human sera, but in only 1 of 8 sera from infants and children. Specific antibodies were found in sera of 13 of the 14 adults with no history of P. carinii pneumonia, and all 19 patients with recently diagnosed P. carinii pneumonia, including 9 patients with P. carinii pneumonia associated with AIDS. The results of this study support previous suggestions that a large proportion of adults have been exposed to P. carinii and provide a basis for the further investigations of host-P. carinii interactions.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Stimulation of choleragen enzymatic activities by GTP and two soluble proteins purified from bovine brain.

Choleragen (cholera toxin) activates adenylate cyclase by catalyzing ADP-ribosylation of Gs alpha, the stimulatory guanine nucleotide-binding protein. It was recently found (Tsai, S.-C., Noda, M., Adamik, R., Moss, J., and Vaughan, M. (1987) Proc. Natl. Acad. Sci. U. S. A. 84, 5139-5142) that a bovine brain membrane protein known as ADP-ribosylation factor or ARF, which enhances ADP-ribosylation of Gs alpha, also increases the GTP-dependent NAD:arginine and NAD:protein ADP-ribosyltransferase, NAD glycohydrolase, and auto-ADP-ribosylation activities of choleragen. We report here the purification and characterization of two soluble proteins from bovine brain that similarly enhance the Gs alpha-dependent and independent ADP-ribose transfer reactions catalyzed by toxin. Like membrane ARF, both soluble factors are 19-kDA proteins dependent on GTP or GTP analogues for activity. Maximal ARF effects were observed at a molar ratio of less than 2:1, ARF/toxin A subunit. Dimyristoyl phosphatidylcholine was necessary for optimal ADP-ribosylation of Gs alpha but inhibited auto-ADP-ribosylation of the choleragen A1 subunit and NAD:agmatine ADP-ribosyltransferase activity. It appears that the soluble factors directly activate choleragen in a GTP-dependent fashion. The relationships of the ARF proteins to the ras oncogene products and to the family of guanine nucleotide-binding regulatory proteins that includes Gs alpha remains to be determined.

ADP Ribose Transferases↗
PubMed1988

Molecular cloning and DNA sequence analysis of the human guanine nucleotide-binding protein Go alpha.

The nucleotide sequence of human Go alpha was determined from a partial human brain cDNA clone and the sequence of the first two 5' coding exons of a human genomic Go alpha clone. Comparison of this sequence with bovine and rat Go alpha shows greater than 90% homology at the nucleotide and deduced amino acid level. There is 100% identity at the amino acid level for the cholera and pertussis toxin-catalyzed ADP ribosylation sites, the putative guanine nucleotide binding, and the GTP hydrolysis sites.

Amino Acid Sequence↗
PubMed1988

Interferon treatment markedly inhibits the development of tumor metastases in the liver and spleen and increases survival time of mice after intravenous inoculation of Friend erythroleukemia cells.

To investigate the effect of interferon treatment on the development of tumor metastases, DBA/2 mice were injected i.v. with 2 X 10(6) Friend erythroleukemia cells (FLC) (equivalent to about 5 X 10(5) LD50). FLC multiplied rapidly in the liver and spleen and all untreated or control treated mice died between 7 and 12 days. Daily treatment of mice with potent preparations of mouse interferon alpha/beta was initiated 3 to 72 hr after i.v. inoculation of tumor cells, at times when FLC were already present in the liver and spleen. Interferon treatment resulted in a 100 to 1,000-fold inhibition of the multiplication of FLC in the liver and spleen and a marked increase in mean survival time. Small numbers of tumor cells persisted in the liver and spleen in some interferon-treated mice and could be recovered by bioassay several weeks after tumor inoculation. Most interferon-treated mice died with tumor in the ensuing months. Three of 34 interferon-treated mice were considered cured as they were alive at 386, 325 and 284 days after tumor inoculation. Daily treatment of tumor-inoculated mice with human recombinant interferons alpha D and alpha BDDD, which had antiviral activity on mouse cells in culture, also increased the survival time of mice injected i.v. with FLC. The use of the interferon-resistant 3C18 line of FLC suggests that the marked inhibition of development of established liver and spleen metastases was not due to a direct effect of interferon on the tumor cells, but was host-mediated.

Animals↗
PubMed1988

Ultrastructural localization of a lysosomal enzyme in resin-embedded lymphocytes.

The intracellular distribution of lysosomal enzymes in lymphocytes has previously been only poorly defined, mainly by cytochemical procedures of low resolution. In the present study we have used a post-embedding immunogold technique to identify the precise ultrastructural localization of a lysosomal enzyme, beta-glucuronidase, in activated lymphocytes embedded in Lowicryl K4M resin. We show that this enzyme is present in the rough endoplasmic reticulum, in the Golgi complex, and in vesicular organelles which probably include lysosomes.

Animals↗