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P East

Publications and source records attributed to P East.

15 recordsLinked to original sources
PubMed2002

cDNA cloning of a salivary chymotrypsin-like protease and the identification of six additional cDNAs encoding putative digestive proteases from the green mirid, Creontiades dilutus (Hemiptera: Miridae).

RT-PCR with degenerate primers was used to amplify partial cDNA fragments for one serine protease gene and three cysteine protease genes from poly(A) RNA isolated from the midgut of the green mirid, Creontiades dilutus. The serine protease amplicon showed homology to insect trypsin-like protease genes, and all three cysteine protease amplicons showed homology to cathepsin L-like protease genes.RT-PCR was also used to amplify fragments of three serine protease genes from salivary gland poly(A) RNA. One of these salivary gland serine protease amplicons was used to screen a whole organism cDNA library to isolate a full length cDNA clone, designated CdSp1 (Accession AY055753), which encodes a putative chymotrypsin-like protease. CdSp1 codes for a 293 amino acid protein that contains a signal peptide and activation peptide, as well as the catalytic triad present in all serine proteases and several of the binding pocket residues characteristic of chymotrypsins. In situ hybridisation showed that the transcript is expressed in the posterior lobe of the principal salivary gland, but not in the anterior lobe of the principal salivary gland, the accessory salivary gland or the midgut.

Amino Acid Sequence↗
PubMed2001

Preliminary characterisation of digestive proteases of the green mirid, Creontiades dilutus (Hemiptera: Miridae).

Protease activities in the secreted saliva, salivary glands and midgut of the green mirid, Creontiades dilutus, were investigated. The saliva and salivary glands had more protease activity than the midgut, but no differences in protease activity levels were detected between male and female mirids, adult mirids and third instar nymphs, or between fed and starved mirids. In the salivary glands, chymotrypsin-like serine proteases predominated, as characterised by inhibitor specificity, basic pH optima, and hydrolysis of N-benzoyl-L-tyrosine p-nitroanilide and N-succinyl-ala-ala-pro-leu p-nitroanilide. The pH optimum of midgut extracts was acidic (pH 4), implying that acidic proteases predominate. However, protease activity was inhibited substantially by both aprotinin and E-64, suggesting the presence of both serine and cysteine proteases in the midgut of the green mirid.

Animals↗
PubMed1999

Characterisation of the helicostatin peptide precursor gene from Helicoverpa armigera (Lepidoptera: Noctuidae).

The gene encoding the helicostatin peptide family was isolated from a Helicoverpa armigera genomic DNA library. The deduced precursor sequence allowed unambiguous identification of all helicostatin peptides and verified the sequences of eight peptides previously isolated. The gene consists of at least three exons and encodes a precursor of 225 amino acids that contains three blocks of tandemly arranged helicostatin peptides including seven copies of the C-terminal sequence -YXFGL followed by a single Gly residue for carboxylamidation. Complete endoproteolytic processing at all possible dibasic cleavage sites would generate the seven helicostatin octapeptides previously purified from larval extracts. If processing was not complete at the third pair of basic amino acids the octadecapeptide (helicostatin IIa) would also be released. Two novel putative helicostatin peptide sequences were identified; YSKFNFGL and ERDMHRFSFGL, both of which had the C-terminal pentapeptide -FXFGL in place of the more usual -YXFGL sequence. Comparison of the helicostatin precursor with that of the cockroaches, locust and flies revealed variation in size, sequence and organisation of the 'allatostatin' precursors across different insect orders. In situ hybridisation histochemistry established that helicostatins are expressed in neurones of the central nervous system and endocrine cells of the midgut, indicating that the helicostatins are true brain-gut peptides. Northern blot analysis identified a single transcript of 1.6 kb in mRNA from whole larvae, isolated central nervous system and gut tissue.

Amino Acid Sequence↗
PubMed1998

Adolescent emotional response to music and its relationship to risk-taking behaviors.

PURPOSE: Adults have frequently been concerned about the adverse influence that music may have on teenagers. This study was designed to examine the relationship between the intensity of emotional response to music and health risk-taking behavior in adolescents. METHODS: Consecutive participants from the University of California, San Diego, Adolescent Medicine Clinics completed a written survey about music preference, emotional response to music using the Positive Affect Negative Affect Schedule (PANAS), and a variety of health-risk behaviors. For each participant, the PANAS scores were summed to give a positive, negative, and total affect score, and health-risk behaviors were assigned a point value based on the level of risk and then summed to give a risk score. RESULTS: Health-risk behavior was found to be correlated with increasing emotional response to music (r = 0.23), whether those emotions were positive (r = 0.19) or negative (r = 0.24). Strong negative emotional response to music in particular was correlated with a history of greater risk behavior, particularly among whites (risk score = 14.0). CONCLUSIONS: Our study indicates that subjects who experience strong negative emotions to music are at an increased risk of participating in a variety of risk-taking behaviors. Further evaluation of the link between emotional response to music and health-risk behaviors will be useful in clarifying the nature of this relationship.

Adolescent↗
PubMed1996

Identification of the dipteran Leu-callatostatin peptide family: characterisation of the prohormone gene from Calliphora vomitoria and Lucilia cuprina.

The prohormone gene encoding the Leu-callatostatin peptides has been isolated from a Calliphora vomitoria genomic DNA library and its homologue was cloned from genomic and cDNA libraries of another blowfly species, Lucilia cuprina. Gene and prohormone structure and organisation are essentially identical in the two species. The Leu-callatostatin gene consists of at least 3 exons. The prohormone is encoded on exons two and three and the two blocks of putative Leu-callatostatin peptides are carried on separate exons. It is 180 amino-acids long, begins with a short signal peptide and contains two blocks of tandemly arranged Leu-callatostatin peptides separated by an acidic spacer region. The prohormone contains 5 copies of the C-terminal sequence -YX FGL characteristic of the Leu-callatostatin family. Complete endoproteolytic processing at all possible pairs of basic amino acids would generate 5 different Leu-callatostatin octapeptides. Two larger Leu-callatostatins could be released if processing was not complete at two of the sites. None of the 3 peptides encoded in the first block was identified in previous purification studies of the callatostatin peptides. The second block, located at the carboxyl end of the prohormone, contains two peptide sequences identical to the previously isolated Leu-callatostatins 1 and 4. The absence of independent copies of Leu-callatostatins 2 and 3 on the prohormone establishes that endoproteolytic cleavage of the precursor does not invariably proceed to completion and that Leu-callatostatin 2 must be derived by N-terminal processing of the parent peptide Leu-callatostatin 1. Reverse transcriptase PCR analysis of mRNA from brain and midgut, the two major sites of Leu-callatostatin expression, shows that the prohormone sequence at these two sites is identical, ruling out the possibility that different populations of peptides are expressed in these two tissues as a result of alternative RNA splicing.

Amino Acid Sequence↗
PubMed1994

[Hyp3]Met-callatostatin. Identification and biological properties of a novel neuropeptide from the blowfly Calliphora vomitoria.

A novel, hydroxyproline-containing neuropeptide, Gly-Pro-Hyp-Tyr-Asp-Phe-Gly-Met-NH2, designated [HYP3]Met-callatostatin, has been identified from extracts of heads of the blowfly Calliphora vomitoria. The peptide is a naturally occurring hydroxylate analogue of Met-callatostatin, a previously identified allatostatin-like peptide, and is present to the extent of 20% of the nonhydroxylated form. In bioassays, both forms of the peptide show allatostatic activity by inhibiting juvenile hormone synthesis and release in the cockroaches Periplaneta americana, Diploptera punctata, and Blattella germanica (IC50 = 100 pM-10 nM). They do not, however, influence juvenile hormone bisepoxide synthesis and release in the blowfly. In flies, [Hyp3]Met-callatostatin inhibits the peristaltic movements of the hindgut, showing a biphasic response (IC50 = 0.5 pM and 0.5 microM) compared with the monophasic response of Met-callatostatin (IC50 = 100 nM). Immunocytochemical studies with Met-callatostatin antisera provide the cytological basis for a myoinhibitory role in the gut since the axons of immunoreactive neurons in the abdominal ganglion project to the ileum. There are also endocrine cells in the midgut that, by releasing the peptides into the hemolymph, would allow the Met-callatostatins to fulfill a neurohormonal role on muscles of the gut and heart. In contrast, there are no Met-callatostatin neural pathways from the brain to the corpus allatum, the gland that produces juvenile hormone. NH2-terminal degradation of Met-callatostatins incubated with the hemolymph of P. americana results in cleavage of the Pro-Tyr bond giving the pentapeptide Tyr-Asp-Phe-Gly-Met-NH2 as a degradation product. In contrast, the Hyp-Tyr bond resists cleavage. With hemolymph from C. vomitoria, no immunoassayable degradation product has been observed with either peptide.

Amino Acid Sequence↗
PubMed1994

Localisation of sulfakinin neuronal pathways in the blowfly Calliphora vomitoria.

The distribution of neurones immunoreactive to antisera raised against the undecapeptide C-terminal fragment of drosulfakinin II (DrmSKII), Asp-Gln-Phe-Asp-Asp-Tyr(SO3H)-Gly-His-Met-Arg-Phe-NH2, has been studied in the blowfly Calliphora vomitoria. Antisera were preabsorbed with combinations of the parent antigen, the tetrapeptide Phe-Met-Arg-Phe-NH2 and cholecystokinin, the vertebrate sulfated octapeptide (CCK-8), Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2, in order to ensure specificity for the sulfakinin peptides of C. vomitoria (the nonapeptide callisulfakinin I is identical to drosulfakinin I and callisulfakinin II differs from DrmSK II only by the presence of -Glu3-Glu4- in place of -Asp3-Asp4-). Only four pairs of sulfakinin-immunoreactive neurons have been visualised in the entire nervous system. These occur in the brain: two pairs of cells situated medially in the caudo-dorsal region close to the roots of the ocellar nerve and two other pairs at the same level but positioned more laterally. Despite the small number of sulfakinin-immunoreactive cells, there are extensive projections to many areas of neuropile in the brain and the thoracic ganglion. The pathway of the medial sulfakinin cells extends into each of the three thoracic ganglia and a metameric arrangement of sulfakinin neuronal projections is also seen in the abdominal ganglia. Neither the dorsal neural sheath of the thoracic ganglion, nor the abdominal nerves contain sulfakinin-immunoreactive material. These observations suggest that the sulfakinins of the blowfly function as neurotransmitters or neuromodulators. They do not appear to have a direct role in gut physiology, as has been shown by in vitro bioassays for the sulfakinins of orthopterans and blattodeans. In addition to the neurones that display specific sulfakinin immunoreactivity, other cells within the brain and thoracic ganglion are immunoreactive to cholecystokinin/gastrin antisera. There are, therefore, at least two types of dipteran neuropeptides with amino acid sequences that are similar to the vertebrate molecules cholecystokinin and gastrin.

Amino Acid Sequence↗
PubMedDate not supplied

Technical and economic strategies of maintenance dialysis in the UK and Nordic Countries.

The technical and economic strategies of maintenance dialysis in the UK and Nordic Countries are described. In particular the concept of 'Therapy Cost', or therapy pricing, as it is also known, in the UK and the concept of 'Patient Flow', which basically plots the flow of patients through the dialysis process, in the Nordic Region are discussed.

Ambulatory Care Facilities↗
PubMedDate not supplied

Use of rat and human in vitro systems to assess the effectiveness and enzymology of deoxyguanine analogs as prodrugs of an antiviral agent.

BRL 55792, BRL 55791, and BRL 55039 are prodrugs of an active antiviral agent 9-(3-hydroxypropoxy) guanine (BRL 44385). The prodrugs were 6-deoxygenated analogs of BRL 44385, with ether groups substituted at the 9-position: BRL 55792 with an (isopropoxymethyloxy)propoxy group, BRL 55791 with a (methoxymethyloxy)propoxy group, and BRL 55039 with an ethoxypropoxy group. Conversion of the prodrugs to BRL 44385 had been demonstrated in vivo in the rat and involved 6-oxidation followed by dealkylation. Metabolism was studied in rat liver in vitro systems to find a model to evaluate BRL 44385 production. Rat hepatocytes performed both reaction steps and were used to assess which of the three prodrugs demonstrated greatest production of the active drug. BRL 55792 demonstrated greatest conversion in vitro, and this was in agreement with in vivo data. The production of BRL 44385 from BRL 55792 was also demonstrated in human hepatocyte incubations, providing evidence that these reactions can occur in humans, thereby increasing confidence that BRL 55792 would be suitable prodrug for human therapy. Further experiments were performed to investigate the enzymes involved in these conversions. The 6-oxidation step occurred in the cytosol. Use of allopurinol and menadione (xanthine and aldehyde oxidase inhibitors) indicated that these conversions were catalyzed exclusively by xanthine oxidase in the rat but mainly by aldehyde oxidase in humans. The dealkylation reaction was detected in hepatocytes but not in homogenates or subcellular fractions. Inhibition of this reaction by aminobenzotriazole and ketoconazole (P-450 inhibitors) indicated that it was mediated by cytochrome P-450.

Aldehyde Oxidoreductases↗
PubMedDate not supplied

Use of rat and human in vitro systems to assess the effectiveness and enzymology of deoxy-guanine analogues as prodrugs of an antiviral agent.

BRL 55792, BRL 55791, and BRL 55039 are prodrugs of an active anti-viral agent 9-(3-hydroxypropoxy) guanine, (BRL 44385). The prodrugs were 6-deoxygenated analogues of BRL 44385 with ether groups substituted at the 9-position: BRL 55792 with an (isopropoxymethyloxy)propoxy group, BRL 55791 with a (methoxymethyloxy)propoxy group, and BRL 55039 with an ethoxypropoxy group. Conversion of the prodrugs to BRL 44385 had been demonstrated in vivo in rat and involved 6-oxidation followed by dealkylation. Metabolism was studied in rat liver in vitro systems to find a model to evaluate BRL 44385 production. Rat hepatocytes performed both reaction steps and were used to assess which of the three prodrugs demonstrated greatest production of the active drug. BRL 55792 demonstrated greatest conversion in vitro and this was in agreement with in vivo data. The production of BRL 44385 from BRL 55792 was also demonstrated in human hepatocyte incubations providing evidence that these reactions can occur in man thereby increasing confidence that BRL 55792 would be a suitable prodrug for human therapy. Further experiments were performed to investigate the enzymes involved in these conversions. The 6-oxidation step occurred in the cytosol. Use of allopurinol and menadione (xanthine and aldehyde oxidase inhibitors) indicated that these conversions were catalyzed exclusively by xanthine oxidase in the rat but mainly by aldehyde oxidase in man. The dealkylation reaction was detected in hepatocytes but not in homogenates or subcellular fractions. Inhibition of this reaction by aminobenzotriazole and ketoconazole (P-450 inhibitors) indicated that it was mediated by cytochrome P-450.

Animals↗