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702. Allatostatins and allatotropins: Is the regulation of corpora allata activity their primary function?

Creator:
Hoffmann, Klaus H., Meyering-Vos, Martina, and Lorenz, Matthias W.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, fyziologie živočichů, hmyz, Crustacea, corpora allata, juvenilní hormony, ekdysteroidy, biosyntéza, kontrola biosyntézy, neuropeptidy, allatostatiny, allatotropiny, fyziologická úloha, 591.1, and 591.5
Language:
English
Description:
More than 60 neuropeptides that inhibit juvenile hormone synthesis by the corpora allata have been isolated from the brains of various insect species. Most of them are characterized by a common C-terminal pentapeptide sequence Y/FXFGL/I/V (allatostatin A family, allatostatin superfamily). Besides the allatostatin A family, allatostatic neuropeptides belonging to other two peptide families (W2W9)-allatostatins or allatostatin B family; lepidopteran allatostatin) were reported. So far, only one allatotropin has been identified. Here we discuss latest literature on the multiplicity and multifunctionality of the allatoregulating neuropeptides, their physiological significance as well as their evolutionary conservation in structure and function., Klaus H. Hoffmann, Martina Meyering-Vos, Matthias W. Lorenz, and Lit
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

703. Allatostatins in Gryllus bimaculatus (Ensifera: Gryllidae): New structures and physiological properties

Creator:
Lorenz, Mathias W., Kellner, Roland, and Hoffmann, Klaus H.
Format:
print, text, and regular print
Type:
article, bibliography, model:article, and TEXT
Subject:
zoologie, hmyz, Ensifera, Gryllidae, Gryllus bimaculatus, juvenilní hormony, biosyntéza, kontrola biosyntézy, neuropeptidy, allatostatiny, farnesol, fyziologické vlastnosti, 595.2/.7, and 591.1
Language:
English
Description:
Four peptides with allatostatic activity were isolated from brains of the Mediterranean field cricket, Gryllus bimaculatus. Three of them (Grb-AST A3: AGMYSFGL-NH2; Grb-AST A4: SRPFGFGL-NH2; Grb-AST A5: GPDHRFAFGL-NH2) belong to the wide-spread family of Y/FXFGL/I-amide peptides, the fourth (Grb-AST B5: AWDQLRPGW-NH2) is a member of the W2W9 - amide family of neuropeptides. All of these peptides are potent inhibitors of juvenile hormone (JH) biosynthesis by cricket corpora allata in vitro, causing 50% inhibition of JH biosynthesis at 0.4-3 × 10-8 M. The two peptides Grb-AST A5 and Grb-AST B5 have virtually the same potency and efficacy in inhibiting JH biosynthesis in vitro. No synergistic effect of the two peptide families with respect to the inhibition of JH biosynthesis could be observed. Peptides of both families decrease the accumulation of methylfarnesoate, the direct precursor of JH, within CA that have been incubated in farnesol-rich medium. This suggests an involvement of these ASTs in the late steps of JH biosynthesis., Mathias W., Roland Kellner, Klaus H. Hoffmann, and Lit
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

706. Allelic and Haplotype Frequencies of the p53 Polymorphisms in Brain Tumor Patients

Creator:
Erik Biroš, Ivan Kalina, Anton Kohút, Bogyiová, E., Šalagovič, J., and Igor Šulla
Format:
print, bez média, and svazek
Type:
article, studie, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Brain tumor, Susceptibility, p53, Polymorphism, 14, and 612
Language:
English
Description:
The polymorphisms of the tumor suppressor gene p53 in exon 4 (p53 BstUI) and in intron 6 (p53 MspI) have been suggested to be associated with the genetically determined susceptibility in diverse types of human cancer. In our hospital-based case-control study, we examined the allele and genotype incidence of these polymorphisms as well as their haplotype combinations in 60 brain tumor patients (27 males and 33 females) and 183 controls without malignancies. The genotype characteristics were determined by the PCR-based RFLP method using DNA extracted from peripheral blood. In this study we show that the p53 BstUI and the p53 MspI polymorphisms are not associated with increased risk of brain tumors. Thus, we conclude that the p53 BstUI and the p53 MspI polymorphic sites within the tumor suppressor gene p53 do not represent genetic determinants of susceptibility to brain tumors., E. Biroš, I. Kalina, A. Kohút, E. Bogyiová, J. Šalagovič, I. Šulla., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

707. Allelic variants of cytochrome P450 monooxygenases: Constitutive and insecticide-mediated expression in a Malaysian strain of the dengue vector, Aedes aegypti (Diptera: Culicidae)

Creator:
El-Garj, Fatma M. A, Wajidi, Mustafa F. F., and Avicor, Silas W.
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, Diptera, Culicidae, Aedes aegypti, cytochrome P450s, structure prediction, mRNA expression, insecticide, 2, and 59
Language:
English
Description:
Cytochrome P450s (P450s) involved in insecticide resistance reduce the efficacy of insecticide-based vector control by rendering vector control ineffective. They are recorded in many species of vectors and have various constitutive and insecticide induction profiles. In this study, the isolation and prediction of the structure of a P450 from a strain of Aedes aegypti originating from Malaysia is reported. Quantitative mRNA expression of this gene and a previously reported P450, CYP4H28v2, in the developmental stages of the mosquito after exposure to sub-lethal concentrations of insecticides is also reported. The isolated P450, CYP4H31v2, is an allelic variant of CYP4H31 and contains several conserved motifs of P450s. The secondary structure of the protein is mostly made up of alpha helices and random coils. The tertiary structure was generated using homology modeling and was of good quality based on structure validation using protein structure assessment tools. CYP4H28v2 and CYP4H31v2 were differentially expressed in the developmental stages of the vector, with a significantly increased expression in adult males. The genes were significantly over-expressed in larvae exposed to deltamethrin and permethrin for 6 h. In the DDT-treated larvae, only CYP4H31v2 was significantly over-expressed after a 6 h exposure. Under-expression of the genes was predominant in larvae treated with the organophosphates malathion and temephos. Though the functions of these P450s are unknown, their response to induction by exposure to insecticides indicates the likely involvement of these genes in insecticide tolerance. and Fatma M. A. El-Garj, Mustafa F.F. Wajidi, Silas W. Avicor.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

710. Allosteric modulation of ligand gated ion channels by ivermectin

Creator:
Hana Zemková, Tvrdonová, V., Anirban Bhattacharya, and Marie Jindřichová
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, iontové kanály, ion channels, cys-loop receptor family, purinergic P2X4 receptor, ivermectin, transmembrane domain, 14, and 612
Language:
English
Description:
Ivermectin acts as a positive allosteric regulator of several ligand gated channels including the glutamate-gated chloride channel (GluCl), γ-aminobutyric acid type-A receptor, glycine receptor, neuronal α 7-nicotinic receptor and purinergic P2X4 receptor. In most of the ivermect in-sensitive channe ls, the effects of ivermectin include the potentiation of agonist-induced currents at low concentrations and channel opening at higher concentrations. Based on mutagenesis, electrophysiological recordings and functional an alysis of chimeras between ivermectin-sensitive and ivermectin-insensitive receptors, it has been concluded that ivermectin acts by insertion between transmembrane helices. The three-dimensional structure of C. elegans GluCl complexed with ivermectin has revealed the details of the ivermectin-binding site, however, no generic motif of amino acids could accurately predict ivermectin binding site for other ligand gated channels. Here, we will review what is currently known about ivermectin binding and modulation of Cys-loop receptor family of ligand-gated ion channels and what are the critical structur al determinants underlying potentiation of the P2X4 receptor channel., H. Zemkova ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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