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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pronuclei of fertilized sheep ova were injected with fusion genes consisting of the mouse metallothionein-I promotor/regulator ligated to either the structural gene for bovine growth hormone (mMTbGH) or to a minigene for human growth hormone-releasing factor (mMThGRF). From a total of 842 sheep ova injected with mMTbGH and transferred into recipient ewes, 47 lambs were born. Two of the lambs were transgenic with mMTbGH, and both had bGH mRNA present in liver, kidney, and gut. In one lamb, plasma growth hormone was as high as 700 ng/ml. From a total of 435 sheep ova injected with mMThGRF and transferred to recipients, 54 lambs were born and 9 fetuses were collected. Nine of the 63 had integrated the mMThGRF gene. One of the nine had high concentrations of immunoassayable hGRF in its plasma and high variable plasma concentrations of ovine growth hormone. The lamb that expressed the hGRF gene did not release GH in response to an hGRF challenge. Four of five fetal offspring of a nonexpressing mMThGRF transgenic ram also contained the mMThGRF gene and, like the sire, failed to express the gene as determined by either liver hGRF mRNA or by plasma hGRF. Growth of the single transgenic lamb expressing hGRF was similar to control lambs. These studies demonstrate efficient introduction of genes into the sheep genome and indicate that transgenes are expressed and heritable.
Mol Reprod Dev 1989
PMID:Production of transgenic sheep with growth-regulating genes. 251 25

Recently, it was found that large quantities of mannitol are present in unsporulated oocysts of the protozoan parasite Eimeria tenella and that these levels diminish during maturation (sporulation). Investigations into the metabolic role of mannitol have led to the discovery that a mannitol cycle is present in this parasite. Prior to these studies the mannitol cycle was found exclusively in fungi. The parasite cycle is similar to that in the fungi although there are distinct differences in coenzyme requirements. The enzymes involved in the parasite pathway include mannitol-1-phosphate dehydrogenase (EC 1.1.1.17), mannitol-1-phosphatase (EC 3.1.3.22), mannitol dehydrogenase (EC 1.1.1.67), and hexokinase (EC 2.7.1.1). Kinetic studies were conducted to determine the Km and specific activities of these enzymes at both ambient temperature (where sporulation occurs) and the chicken's body temperature (41 degrees C). The data suggest that mannitol is produced during oocyst formation in the chicken gut and accumulated as an energy reserve for sporulation. The apparent lack of mannitol kinase in the organism and the Km values for the dehydrogenases in the reverse direction all indicate that the cycle only proceeds in one direction. In addition to serving as an energy storage system the cycle may also function as an electron 'sink' for the parasite which must survive in the anaerobic environment of the gut.
Mol Biochem Parasitol 1989 Jan 15
PMID:Evidence for and characterization of a mannitol cycle in Eimeria tenella. 253 47

Klebsiella pneumoniae 1033-5P14 and its P1-sensitive derivative KAY2026 were found to be resistant to lambda although they contained a LamB protein, active as a maltoporin. Sensitive derivatives could only be obtained after introduction of the pTROY9 plasmid which expresses lamB and the corresponding lambda receptor from Escherichia coli K12 at high levels. Lysogenic derivatives from such strains were shown to carry the phage at secondary att sites and to give high titer lysates when induced. The use of lambda plac-Mu hybrid phages allowed the isolation from several operons of lacZ fusions orientated in, or against, the direction of transcription. Such insertions could subsequently be used to isolate stable Hfr strains by allowing homologous recombination to take place between the lac genes in the inserted hybrid phages and those of plasmid F' ts114 lac+ zzf20::Tn10. The Hfr strains were able to transfer K. pneumoniae chromosomal genes and allowed the mapping of such genes. Characteristic differences between this conjugation system and that of Escherichia coli K12 are discussed. The insertions also allowed determination of the direction of transcription of the gut gene, the newly mapped scr gene and of the sor gene cluster encoding enzymes for the metabolism of D-glucitol, sucrose and L-sorbose.
Mol Gen Genet 1989 Feb
PMID:The use of lambda plac-Mu hybrid phages in Klebsiella pneumoniae and the isolation of stable Hfr strains. 254 Apr 16

A 43-kDa putative lipoprotein receptor (Sj43) of adult Schistosoma japonicum worms has been identified using ligand blotting techniques. Single and two dimensional electrophoretic analyses showed that Sj43 consisted of a single acidic polypeptide with multiple lipoprotein specificity. The molecule bound 125I-labelled low-density (apo-B), very low-density or high-density (apo-A and/or apo-C) lipoproteins from different mammalian hosts that are permissive to S. japonicum infection, but did not bind mouse apo-A containing lipoprotein. The binding of 125I-labelled lipoprotein to Sj43 could be inhibited by unlabelled human LDL, EDTA or Suramin, or by chemical modification of lipoprotein lysine or arginine residues. Sj43 was localised at the parasite's tegument and gut lining.
Mol Biochem Parasitol 1989 Jun 01
PMID:Identification of a multispecific lipoprotein receptor in adult Schistosoma japonicum by ligand blotting analyses. 254 94

During lactation, a dramatic rise in serum PRL stimulates milk production, resulting in a substantial rise in calcium mobilization from gut and bone. We found that the production of a newly characterized calcium-mobilizing PTH-like peptide (PTH-LP) by mammary tissue was tightly linked to lactation, suggesting a possible role for PRL in the expression of PTH-LP. Here it is shown that suckling results in both an elevation in serum PRL and the appearance of PTH-LP mRNA in mammary tissue. Bromocriptine, a potent inhibitor of PRL secretion, blocked the suckling-associated rise in serum PRL and the subsequent induction of PTH-LP mRNA in mammary gland. Furthermore, injection of PRL dramatically induced PTH-LP mRNA in unsuckled puerperal glands, but not in glands on day 21 of pregnancy. Thus, the correlation between serum levels of PRL and the expression of PTH-LP mRNA in mammary tissue extends the role of PRL in milk production and suggests a possible mechanism for the PRL effects on calcium metabolism.
Mol Endocrinol 1989 Sep
PMID:The mRNA encoding a parathyroid hormone-like peptide is produced in mammary tissue in response to elevations in serum prolactin. 260 67

The indirect immunoperoxidase method was used to describe time of appearance, morphology and topography of 5-hydroxy- tryptamine-like immunoreactive (5-HT-LI) cells in the gut of chick embryos, newborn and adult chickens. The earliest cells were seen in the ileum at 11 days, in the caeca at 14 and in the colon at 9 days. At first appearance they were ovoid or pyramidal but later became more irregular because of the numerous apical and basal processes. The peak of cell concentration at hatching, was in the ileal samples, whereas in the colon these cells were also abundant in adults both throughout the villi and the glands. In sections of adult ileum, on the contrary, they could be found mainly in the glands.
Cell Mol Biol 1989
PMID:5-HT-like immunoreactive cells in chicken intestine: ontogenesis, morphology and topography. 267 23

SPARC (Secreted Protein that is Acidic and Rich in Cysteine) is a Ca2+-binding, stress-related protein released in vitro by both malignant and normal cells derived from all primordial germ layers. It is specifically elevated in endothelial cells as a result of "culture shock" (characterized by high levels of proliferation and migration) and exhibits density-dependent secretion. Exposure of bovine aortic endothelial cells to endotoxin results in a 70-100% increase in secreted protein, with a three-fold increase in SPARC. Immunofluorescence histochemistry on mouse tissues revealed (a) a preferential association of SPARC with highly proliferative cells (e.g., gut epithelia, mammary gland, and epidermis), (b) a cell surface or stromal location in thymus, lung, and salivary gland, (c) staining of epididymidal epithelium and testicular cells, and (d) an association with somites of 14 d mouse embryos. We envision SPARC as an extracellular modulator of Ca2+ and other cation-sensitive proteins/proteinases, that facilitates cellular proliferation in response to injury and to developmental signals.
J Mol Cell Cardiol 1989 Feb
PMID:SPARC: a Ca2+-binding extracellular protein associated with endothelial cell injury and proliferation. 273 23

Octapamine receptors are widely distributed in invertebrate species, yet little is known about their biochemical structure or tissue localization, in part because there exist no high affinity or irreversible ligands for these receptors. This paper characterizes 2-(2,6-diethyl-4-azidophenylimino)imidazolidine (NC-5Z), a new, high affinity octopamine receptor probe that binds reversibly and, under photolyzing conditions, irreversibly to membrane-associated octopamine receptors. Under reversible conditions NC-5Z is a full agonist, 50-100 times more potent than octopamine in activating the highly enriched and specific octopamine-sensitive adenylate cyclase of the firefly light organ. NC-5Z shows a similar potency in cockroach muscle and thoracic ganglia and in tobacco hornworm nerve cord. Activation of light organ adenylate cyclase by NC-5Z is nonadditive to that caused by octopamine and can be blocked by antagonists, including mainserin (Ki = 0.9 microM), cyproheptadine (Ki = 5 microM), phentolamine (Ki = 20 microM), and propranolol (Ki = 75 microM). These constants agree well with those for the same antagonists in inhibiting stimulation due to octopamine. In physiological studies, NC-5Z mimics the action of, but is more potent than, octopamine in stimulating light emission in intact firefly tails and in disrupting motor behavior and feeding of tobacco hornworms. Under reversible conditions, [3H]NC-5Z, the tritiated derivative of NC-5Z, binds to light organ membranes with an apparent affinity (0.59-0.7 microM) similar to that (0.35-0.7 microM) for NC-5Z in activating adenylate cyclase. Under photolyzing conditions, NC-5Z irreversibly activates light organ adenylate cyclase, and this can be blocked by an excess of octopamine. Under similar conditions, [3H]NC-5Z binds irreversibly to light organ membranes and to membranes from tobacco hornworm nerve ganglia, fat body, and gut. This binding is reduced by prior incubation with octopamine agonists, including octopamine, demethyl-chlordimeform, and 2-(phenylimino)imidazolidines, but not by norepinephrine, dopamine, serotonin, or histamine. Irreversible binding is also reduced by prior incubation with antagonists, most effectively (55% of total binding) by mianserin. The apparent affinity of [3H]NC-5Z for membrane binding, as reflected by its ability to be displaced by mianserin, is altered by GTP. In autoradiographic studies of whole tissue, [3H]NC-5Z shows irreversible, mianserin-displaceable labeling of intact firefly light organs. Taken together, these data indicate that NC-5Z and [3H]NC-5Z are potent and selective agonists of octopamine receptors in a variety of tissues.(ABSTRACT TRUNCATED AT 400 WORDS)
Mol Pharmacol 1989 Jul
PMID:Development of a photoaffinity ligand for octopamine receptors. 274 29

Monoclonal IgG1, IgG2a, IgG2b and IgG2c were prepared from rat hybridoma cells treated with tunicamycin in order to inhibit N-linked glycosylation. The IgG produced by these cells was about 70% lower in carbohydrate content compared to IgG from equivalent untreated cells, but was similar to the corresponding normal IgG in terms of antigen binding. However, the ability of carbohydrate deficient (CHO-) IgG to bind in vitro to Fc receptor extracted from jejunum of neonatal rats was impaired in most cases and, in all but one case, the amount of CHO- IgG transported from gut lumen to blood in vivo was markedly reduced. No reduction in binding of normal IgG to extracted receptor was observed in the presence of various sugars. It is postulated that N-linked carbohydrate acts to stabilize the structure within the IgG molecule which is responsible for binding to this Fc receptor, possibly in the CH2 domain.
Mol Immunol 1989 May
PMID:Role of carbohydrate in binding of IgG to the Fc receptor of neonatal rat enterocytes. 277 Jul 47

We have reported previously the localization of the 49 amino acid peptide pancreastatin to all identifiable endocrine cells of porcine gut, pancreas and adrenal, thyroid and pituitary glands. In this study, we have investigated the occurrence of pancreastatin in a series of human neuroendocrine tumours using an antibody to whole synthetic porcine pancreastatin. The most consistent immunostaining for pancreastatin was found in carcinoid tumours of ileum (four out of six), rectum (four out of six), ovary (two out of two) and lung (nine out of 10). Radioimmunoassay of tumour extracts showed that the concentrations of pancreastatin in ileal carcinoids were very high (mean 71.6, range 31.0-184.0 pmol g-1). The high rate of positivity in lung carcinoids contrasted sharply with the results of 10 pulmonary small cell carcinomas which displayed no immunoreactivity and contained minimal concentrations of pancreastatin (mean 2.0, range 0-6.0 pmol g-1). Extra-adrenal paragangliomas also contained pancreastatin (seven out of 10), but although radioimmunoassay detected peptide in phaeochromocytomas (mean 29.8, range 8.0-69.0 pmol g-1), immunocytochemistry did not. Porcine pancreastatin shows structural homology with bovine chromogranin A, an observation which has led to suggestions that chromogranin is a precursor for the peptide. More recently, a sequence homologous to porcine pancreastatin has been identified in the human chromogranin A molecule. In this study, immunostaining with an antiserum to human chromogranin gave positive results in most cases of each tumour type except the small cell carcinomas. The lack of consistent relationships between chromogranin and pancreastatin immunoreactivities may reflect the fact that the antiserum to pancreastatin was raised against the porcine peptide. When antibodies to human pancreastatin become available, the peptide may prove to be a more consistent marker for neuroendocrine tumours.
Mol Cell Probes 1988 Sep
PMID:The occurrence of pancreastatin in tumours of the diffuse neuroendocrine system. 285 38


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