Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was undertaken to test the hypothesis that external stimuli acting through the central nervous system perturb the normal gastrointestinal response to meals. Thus, in 4 healthy volunteers we used a multilumen gastroduodenal tube system that allowed simultaneous measurements of gastroduodenal motility, gastric emptying rate, gastric acid secretion, and pancreatic trypsin output. Blood pressure, pulse rate, and skin temperature were also monitored for autonomic response. All subjects were studied on 2 days, receiving on each day two identical test meals. After one of the meals on each day, vertigo was induced by labyrinthine stimulation (ear irrigation with ice water) while the other meal was followed by one of two controls, ear irrigation at 37 degrees C (control stimulation) on 1 day and no stimulation on the other, the order of the tests being randomized. Labyrinthine stimulation at subnauseant levels resulted in a consistent and reproducible delay in gastric emptying of the meal. Further, in 2 of the 4 subjects a marked and reproducible alteration of the postprandial duodenal motility pattern occurred, with a change to one resembling the fasted state, even though nutrients continued to be present in the stomach. Duodenogastric reflux and gastric acid output remained unchanged. Trypsin output decreased initially but later returned to control values. These studies emphasize the role of the central nervous system in the control of gut function after feeding. Labyrinthine stimulation nay be a useful method for investigating inhibitory and disruptive effects of centrally acting stimuli on the human upper gut.
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PMID:Perturbation of gastric emptying and duodenal motility through the central nervous system. 712 28

The counts of Streptococcus faecium SY1 in the duodenums of gnotobiotic chicks exceeded the counts in their crops, indicating that multiplication was occurring in the anterior small intestine. This growth was related to adhesion to the gut wall which could be demonstrated by viable counts of macerated washed duodenal tissue. Scanning electron microscopy demonstrated that adhesion occurred in restricted areas on the surface of the villus, and transmission studies showed the presence of a thick extracellular layer on the bacterium. Attachment of S. faecium SY1 was confirmed in vitro by using chicken duodenal brush borders. The washings, produced during the preparation of the brush borders, increased the number of S. faecium adhering to the brush borders. This enhancing effect was due to the presence of trypsin in the duodenal washings. However, the effect was not dependent on the enzymatic activity of the trypsin molecule. The initial adhesion was not prevented by pretreatment of the brush borders with soy bean trypsin inhibitor. There were, therefore, two adhesion systems operating, only one of which was dependent on trypsin. Pretreatment of brush borders with trypsin digested them, but they remained intact in the presence of S. faecium SY1, indicating that the enzymatic activity was being inhibited. This effect was specific for the adhering strain of S. faecium SY1; the nonadhering S. faecium strain CRS23 and an adhering strain of Lactobacillus sp. were inactive, as was strain SY1 when adhesion was prevented by including sodium periodate in the test system. The colonizations of the gut by strains of S. faecium of differing adhesive abilities were compared. The nonadhering strain CRS23 showed reduced ability to colonize the duodenum, but the penicillin-resistant mutant of S. faecium SY1, which had reduced adhesive ability but could still attach to a lesser degree, was able to colonize the duodenum as efficiently as the parent strain.
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PMID:Attachment of Streptococcus faecium, to the duodenal epithelium of the chicken and its importance in colonization of the small intestine. 724 97

Crystals were purified from four serotypes of the insect pathogen Bacillus thuringiensis. Crystals from these serotypes were similar in amino acid and N-terminal analyses, but differed in their toxicity to two species of Lepidoptera and in their immunological properties. Toxic polypeptides were obtained following trypsin digestion of solutions of the crystals. In two strains (serotypes 3 and 9) this fraction contained only one polypeptide. Similar results were obtained when dissolved crystals were digested with other proteolytic enzymes or with gut contents from Pieris brassicae. The trypsin-resistant polypeptide was further purified by gel and ion-exchange chromatograhy and had a molecular weight of about 70,000, estimated by gel chromatogrpahy and gel electrophoresis. No evidence was obtained for a toxin of lower molecular weight. This purified toxin accounted for most, if not all, of the toxic activity originally present in the crystal solution and was active by injection and ingestion. The purified toxic fraction from serotype 1 appeared to contain two polypeptides, one of which corresponded to that found with serotypes 3 and 9. There were no major differences in the composition of crystals from different serotypes of B. thuringiensis and it is concluded that the trypsin-resistant polypeptide represents the active insecticidal toxin of the crystal.
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PMID:Purification of the insecticidal toxin in crystals of Bacillus thuringiensis. 742 53

Female Aedes aegypti that were given a blood meal by enema deposited yolk in their oocytes and synthesized trypsinlike enzymes in their midgut. When females were given an enema of Aea-TMOF (Trypsin Modulating Oostatic Factor) (NH2-YDPAPPPPPP-COOH) and blood both egg development and trypsin biosynthesis were inhibited. Similar results were observed if TMOF was mixed with the blood meal and fed to female mosquitoes through a membrane. Renin inhibitor (NH2-PHPFHFFVYK-COOH) or poly proline given by enema with the blood meal did not affect egg development or trypsin biosynthesis. Feeding of TMOF analogs P1 (NH2-YDPAP-COOH) or P4 (NH2-YDPAPPPP-COOH) inhibited trypsin biosynthesis in the midgut. Injecting or giving an enema of an amidated peptide (NH2-WRPGPPPPPP-CONH2) of HIV-2 X-ORF protein also inhibited egg development and trypsin biosynthesis in the mosquito gut. When [3H]TMOF was purified by high performance liquid chromatography (HPLC) and fed with the blood meal through a membrane to female mosquitoes, [3H]TMOF outside the gut increased linearly for the first 24 h and 28% of the hormone was found outside the gut at 72 h. These results suggest that TMOF and its active analogs traverse the gut epithelial cells into the hemolymph, bind TMOF gut receptor(s) and modulate trypsin biosynthesis.
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PMID:Feeding the mosquito Aedes aegypti with TMOF and its analogs; effect on trypsin biosynthesis and egg development. 748 Aug 77

Trypsin genes in Anopheles gambiae are arranged as a tightly clustered gene family consisting of seven related coding sequences, devoid of introns. The two blood meal-inducible members of this family, Antryp1 and Antryp2, were shown to play a crucial role in the breakdown of the blood meal constituents. The role of Antryp3,4,5,6, and Antryp7 in the process of blood meal digestion remains to be elucidated. We have examined the localization and the expression patterns of these trypsins as well as the functional interactions in blood meal digestion between trypsins and other gut-specific proteases. Northern blot and RT-PCR analysis indicated that the genes Antryp3,4,5,6, and Antryp7 are all constitutively expressed in unfed female mosquitoes. Soon after blood feeding the mRNA of these trypsin genes became undetectable and appeared again at the end of the gonotrophic cycle. The blood meal-inducible trypsin Antryp1 was also constitutively expressed at low level in the gut of adult female mosquitoes. This trypsin was the only member of this gene family to be expressed in the gut of male and female pupae. By using antisera that specifically recognized recombinant Antryp4 we were able to show that the corresponding protein in Anopheles is synthesized and stored in the gut epithelium of unfed females as zymogen. Secretion and activation of this trypsin was shown to occur in the midgut lumen immediately after fluid ingestion and independently of the protein content of the meal. Recombinant trypsins expressed in Escherichia coli, with the exception of Antryp5 and Antryp6, were able to activate in vitro recombinant A. gambiae chymotrypsinogen, thus suggesting that blood meal ingestion is able to trigger a cascade of events leading to the activation of several proteases.
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PMID:Constitutive and blood meal-induced trypsin genes in Anopheles gambiae. 749 34

Levels of canine tryptase from various tissues were quantified using a competition enzyme-linked immunosorbent assay (ELISA). The assay utilises an affinity-purified rabbit anti-tryptase antibody in the solid phase and alkaline-phosphatase conjugated tryptase together with unlabelled tryptase in the fluid phase. The assay will rapidly quantify 40-5000 ng ml-1 of tryptase in tissue extracts. Tissues from the skin, gut, liver and lung were studied, of which canine gut appeared to contain the highest levels of tryptase per milligram wet weight, which may suggest an important role for this enzyme at this site. This assay may prove valuable in assessing the role of mast cells in various disease states in the dog.
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PMID:Mast cell tryptase levels in normal canine tissues. 750 84

The sequences of two folliculostatic peptides of the fleshfly Neobellieria bullata have been determined recently. The first peptide (Neb-TMOF: H-NPTNLH-OH), originates from a 75 kDa precursor protein found in vitellogenic oocytes. The hexapeptide directly inhibits the synthesis of trypsin-like enzymes in the gut, and thus lowers the concentration of yolk polypeptides in the hemolymph. It also inhibits the biosynthesis of ecdysone in the larval ring gland. Therefore, it could also be named prothoracicostatic hormone (Neb-PTSH). The second peptide (Neb-colloostatin: H-SIV-PLGLPVPIGPIVVGPR-OH) acts on previtellogenic follicles and is a cleaved product of a collagen-like precursor molecule. Our results indicate that peptides that are cleaved from matrix proteins could act as growth-inhibiting factors. Gonadotropin releasing hormone (GnRH)-immunolike peptides were not identified, but progress is being made in the isolation and characterization of factors which stimulate cAMP production by the ovary. Using these results, a novel model of growth control in which matrix proteins play an important role as a potential source of growth regulators has been developed.
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PMID:Folliculostatins, gonadotropins and a model for control of growth in the grey fleshfly, Neobellieria (sarcophaga) bullata. 762 97

Tobacco plants were transformed with a cDNA clone of chymotrypsin/trypsin-specific potato proteinase inhibitor II (PI2) under the control of a constitutive promoter. Although considerable levels of transgene expression could be demonstrated, the growth of Spodoptera exigua larvae fed with detached leaves of PI2-expressing plants was not affected. Analysis of the composition of tryptic gut activity demonstrated that only 18% of the proteinase activity of insects reared on these transgenic plants was sensitive to inhibition by PI2, whereas 78% was sensitive in insects reared on control plants. Larvae had compensated for this loss of tryptic activity by a 2.5-fold induction of new activity that was insensitive to inhibition by PI2. PI2-insensitive proteolytic activity was also induced in response to endogenous proteinase inhibitors of tobacco; therefore, induction of such proteinase activity may represent the mechanism by which insects that feed on plants overcome plant proteinase inhibitor defense.
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PMID:Adaptation of Spodoptera exigua larvae to plant proteinase inhibitors by induction of gut proteinase activity insensitive to inhibition. 764 35

Both human and mouse c-kit ligand induced differentiation of human mast cells in a long-term culture of the mononuclear cells of umbilical cord blood. Growth factor activity for human mast cells present in conditioned medium of BALB/3T3 fibroblasts was due to mouse c-kit ligand. Recombinant c-kit ligand induced differentiation and proliferation of mast cell progenitors in early stages of culture. However, apparent selective growth of mast cells by c-kit ligand in cord blood cell cultures is mainly due to the effect of the cytokine to selectively maintain survival of immature mast cells. Electron microscopic analysis indicated that human mast cells developed by c-kit ligand were similar to human mast cells in the lung and gut mucosa, while those developed in coculture of cord blood cells with Swiss albino/3T3 fibroblasts were similar to skin mast cells. This conclusion was supported by the fact that the majority of mast cells developed by c-kit ligand contained only tryptase in their granules, whereas those developed in the cocultures contained both tryptase and chymase. It was also found that mast cells developed by c-kit ligand were immature even after culture for 14 weeks. Nevertheless, these cells express Fc epsilon RI, and could be sensitized with human IgE for anti-IgE-induced release of histamine, prostaglandin D2, and leukotriene C4.
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PMID:Development of human mast cells from umbilical cord blood cells by recombinant human and murine c-kit ligand. 767 63

Deletion of amino acid residues 370 to 375 (D2) and single alanine substitutions between residues 371 and 375 (FNIGI) of lepidopteran-active Bacillus thuringiensis CryIAb delta-endotoxin were constructed by site-directed mutagenesis techniques. All mutants, except that with the I-to-A change at position 373 (I373A), produced delta-endotoxin as CryIAb and were stable upon activation either by Manduca sexta gut enzymes or by trypsin. Mutants D2, F371A, and G374A lost most of the toxicity (400 times less) for M. sexta larvae, whereas N372A and I375A were only 2 times less toxic than CryIAb. The results of homologous and heterologous competition binding assays to M. sexta midgut brush border membrane vesicles (BBMV) revealed that the binding curves for all mutant toxins were similar to those for the wild-type toxin. However, a significant difference in irreversible binding was observed between the toxic (CryIAb, N372A, and I375A) and less-toxic (D2, F371A, and G374A) proteins. Only 20 to 25% of bound, radiolabeled CryIAb, N372A, and I375A toxins was dissociated from BBMV, whereas about 50 to 55% of the less-toxic mutants, D2, F371A, and G374A, was dissociated from their binding sites by the addition of excess nonlabeled ligand. Voltage clamping experiments provided further evidence that the insecticidal property (inhibition of short-circuit current across the M. sexta midgut) was directly correlated to irreversible interaction of the toxin with the BBMV. We have also shown that CryIAb and mutant toxins recognize 210- and 120-kDa peptides in ligand blotting. Our results imply that mutations in residues 370 to 375 of domain II of CrylAb do not affect overall binding but do affect the irreversible association of the toxin to the midgut columnar epithelial cells of M. sexta.
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PMID:Single amino acid changes in domain II of Bacillus thuringiensis CryIAb delta-endotoxin affect irreversible binding to Manduca sexta midgut membrane vesicles. 773 Feb 54


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