Synthesis and biological activity of the mono- and di-galactosyl-vespulakinin 1 analogues.

Syntheses are described of some mono- and di-glycosylated analogues of vespulakinin 1. The solid phase procedure, based on the Fmoc chemistry, was used to prepare (Gal alpha)Thr3-vespulakinin 1, (Gal beta)Thr3-vespulakinin 1 and the di-glycosylated analogue ((Gal alpha)Thr3, (Gal alpha)Thr4-vespulakinin 1. The beta-glycosylated derivative was also prepared by the continuous flow variant of the Fmoc polyamide method. The synthesized glycopeptides were purified and characterized by amino acid analysis, optical rotation, analytical HPLC, 1H- and 13C-NMR and FAB-MS. Preliminary pharmacological experiments showed that the carbohydrate-free vespulakinin 1 is less active than bradykinin (about 0.3 times on a molar basis) when tested by guinea pig rectum contraction, and the two monoglycosylated analogues are equiactive (about 0.9 times the bradykinin activity). The most active derivative, the (Gal alpha)Thr3, (Gal alpha)Thr4-vespulakinin 1 analogue, was about 2.5 times as active as bradykinin.     

Alpha-adrenoceptor-mediated glucose release from perifused catfish hepatocytes.

In fish liver catecholamines bind to beta-adrenoceptors (AR) and increase glucose release via cAMP augmentation. Alpha1-AR have recently been shown to mediate IP3 and Ca2+ elevation in catfish and eel hepatocytes, although their coupling to a physiological response has remained doubtful. We have perifused isolated catfish hepatocytes in Bio-Gel P4 columns with epinephrine in the presence of prazosin and/or propranolol, alpha- and beta-AR antagonists, respectively. Ten nM epinephrine stimulated glucose release approximately 3-fold, and this effect was completely antagonized by the simultaneous presence of both alpha- and beta-AR blockers. The two AR antagonists separately inhibited about one-third and two-third of the total stimulation, respectively. Through alpha-AR occupancy, epinephrine provoked a significant increase of glucose release whereas no stimulation was detected in Ca2+-depleted hepatocytes. Glucose release was strongly elevated by both ionomycin and dibutyryl cAMP. These results represent the first direct evidence that alpha-AR transduction pathway is involved in epinephrine-induced glucose release from fish hepatocytes.     

Anionic detergents in Mytilus Galloprovincialis of the gulf of Naples

The authors have investigated on the anionics detergents rate inside the Mytilus Galloprovincialis, used as animal-monitor of the environment state of a certain part of the Gulf of Naples. The data concerning 14 zones in which were drown mussels cultivated in the Gulf of Naples resumed in a specific list, shown an high concentration of above detergents.     

Population genetics of red cell and serum markers in the four Albanian communities of Molise, Italy

In this paper phenotype and gene frequencies of ten genetic markers (AK, AP, EsD, 6-PGD, PGM1, PGM2, Hb, Alb, Cp and Hp) of the four Albanian communities (Campomarino, Montecilfone, Portocannone and Ururi) living in Molise are reported. The gene frequencies show a high variability. The heterogeneity analysis among these villages could demonstrate significant differences between Campomarino and Montecilfone and between Campomarino and Ururi. It is interesting to note that the demographic analysis has shown the highest rate of immigration and the lowest percentages of endogamy, Albanian surnames and Albanian-speaking individuals in Campomarino. Against that Montecilfone and Ururi are showing opposite values for the same parameters. The genetic data are also indicating some differences between these Albanian communities and the Italian population. A comparison with the present population of Albany is not possible because of the lack of data.     

Solution synthesis of the glyco-hexapeptide sequence of the human oncofetal fibronectin defined by monoclonal antibody FDC-6.

The glyco-hexapeptide sequence H-Val-(GalNAc-alpha)Thr-His-Pro-Gly-Tyr-OH, was synthesized in solution by the segment condensation procedure and the stepwise procedure. A peracetylated, O-galactosaminyl threonine derivative was used for incorporating the glycosylated amino acid residue into the peptide chain. A consistent racemization occurred during the acylation of H-His-Pro-Gly-Tyr(Bzl)-OBzl with Z-Val-[GalNAc(Ac)3-alpha]Thr-OH by the BOP-HOBt procedure and the D-allothreonine containing glyco-hexapeptide was isolated in about 20% yield. Stepwise elongation of the C-terminal tetrapeptide with Fmoc-[GalNAc(Ac)3-alpha]Thr-OH and Z-Val-OH, in the presence of the same coupling reagents, yielded the L-threonine containing diastereoisomer without detectable racemization. A side product, the Nim-ethoxycarbonylated hexapeptide derivative, formed during the EEDQ-mediated condensation of Fmoc-[GalNAc(Ac)3-alpha]Thr-OH with the C-terminal tetrapeptide, was isolated and characterized. Preliminary studies showed that the synthetic glycohexapeptide is a good competitive inhibitor of the binding of the FDC-6 monoclonal antibody to the oncofetal fibronectin, supporting the idea that it should represent the minimum essential structure required for the FDC-6 activity.     

The NADP+-binding site of ferredoxin-NADP+ reductase. Sequence of the peptide containing the essential lysine residue

The flavoprotein ferredoxin-NADP+ reductase is inactivated and loses its ability to bind NADP+ during covalent modification of a lysine by 5-dimethylaminonaphthalene-1-sulfonyl chloride (dansyl chloride) [Zanetti, G. (1976) Biochim. Biophys. Acta 445, 14-24]. The substrate NADP+ gives almost complete protection against inactivation and modification. These observations are extended in this report by the characterization of an octapeptide containing the dansyl-lysine which was isolated by high-performance liquid chromatography from tryptic digests of protein modified with radiolabeled reagent. The amount of this peptide was severely reduced in protein modified in the presence of NADP+. The sequence of the dansyl-peptide, only partially obtained by Edman degradation, was completed by analysis of the fragments resulting from thermolysin digestion of the purified tryptic dansyl-peptide. Thus, the octapeptide containing the essential lysine residue has the following sequence: H2N-Ser-Val-Ser-Leu-Cys-Val-Lys-Arg-COOH. A comparison with corresponding sequences of other known NADP+-dependent dehydrogenases is attempted.