Large-scale mapping of bioactive peptides in structural and sequence space

Health-enhancing potential bioactive peptide (BP) has driven an interest in food proteins as well as in the development of predictive methods. Research in this area has been especially active to use them as components in functional foods. Apparently, BPs do not have a given biological function in the containing proteins and they do not evolve under independent evolutionary constraints. In this work we performed a large-scale mapping of BPs in sequence and structural space. Using well curated BP deposited in BIOPEP database, we searched for exact matches in non-redundant sequences databases. Proteins containing BPs, were used in fold-recognition methods to predict the corresponding folds and BPs occurrences were mapped. We found that fold distribution of BP occurrences possibly reflects sequence relative abundance in databases. However, we also found that proteins with 5 or more than 5 BP in their sequences correspond to well populated protein folds, called superfolds. Also, we found that in well populated superfamilies, BPs tend to adopt similar locations in the protein fold, suggesting the existence of hotspots. We think that our results could contribute to the development of new bioinformatics pipeline to improve BP detection.Fil: Nardo, Agustina Estefania. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Añon, Maria Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Parisi, Gustavo Daniel. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Drug-induced changes in chromatin ultrastructure and nuclear basic proteins of the neutrophils of chronic schizophrenics

1. 1. Electron microscopic study of the neutrophils revealed that the chromatin of drug-free Schizophrenics as compared with that of controls has an increased readiness to decondense. Treatment of these patients for a month with pimozide showed that the chromatin of most neutrophils acquired an increased resistance to decondensation. 2. 2. The electrophoretic pattern of the acid extractable nuclear proteins of the neutrophils of chronic schizophrenic patients and control individuals did not show significant differences as to the number and intensity of the major bands. Administration of pimozide to these patients revealed several changes in their electrophoretic pattern. These changes tended to disappear on discontinuation of the drug. © 1978

Acute tolerance to the excitatory effects of opioids in the rat hippocampus

Prolonged iontophoretic administrations of δ‐ and μ‐selective opioid receptor agonists were conducted in the hippocampus of rats, in order to study the possible development of acute tolerance to the excitatory effects of the opioids. Acute tolerance (AT) to the excitatory effects of the 8‐selective opioid receptor agonist Tyr‐D‐Ser‐Gly‐Phe‐Leu‐Thr (DSLET) was observed when the drug was applied locally for 3–5 min in the CA1 hippocampal pyramidal neurons. The acute tolerance was expressed as a decrease in the commissurally evoked spike responsiveness during peptide's administration and led to a long‐lasting potentiation of the population spike (PS) upon its withdrawal. In all cases, where AT and spike potentiation were evident, the population excitatory postsynaptic potential (pEPSP) remained unaltered. Pharmacological studies of AT and long‐lasting spike potentiation showed the following: (1) the non‐selective opioid receptor antagonist, naloxone, while effective in blocking the excitatory effects of DSLET when applied prior and during the application of the latter, failed to exhibit and effect on the long‐lasting potentiating effect of the opioid; and (2) during the spike potentiation phase, administration of DSLET exhibited a depressant effect towards baseline values. This depressant effect of the opioid was evident 2–3 min from the beginning of the application and was completely antagonized by naloxone. The above results show that the development of acute tolerance to the excitatory effects of the DSLET led to long‐lasting spike potentiation, which manifests a withdrawal phenomenon. © 1995 Wiley‐Liss, Inc. Copyright © 1995 Wiley‐Liss, Inc