Antinociceptive and Met-enkephalin releasing effects of tachykinins and substance P fragments

Substance P (SP), physalaemin, SP4-11, SP5-11 and the SP5-11 analog DiMe-C7 induce an antinociceptive effect in rats after intraventricular administration. Other tachykinins and the N-terminal fragments of SP are inactive. All antinociceptive peptides increase the Met-enkephalin efflux from slices of rat periaqueductal gray matter and their antinociceptive potency is correlated with their capacity to release Met-enkephalin. The results, discussed in the light of current theories on different tachykinin receptors, suggest that the SP-P receptor subtype may be involved in the control of noxious stimulation elicited by SP at supraspinal levels.     

Concomitant regulation of hippocampal calcium antagonist receptors and calcium uptake by substance P

The interaction of various neuropeptides with calcium antagonist binding was investigated in rat hippocampus. Among the peptides examined Substance P selectively increased the binding of phenylalkylamine and dihydropyridine calcium antagonists; this action was receptor mediated. No effect was observed with Substance P in other brain areas and with neurotensin and met-enkephalin in all the areas examined. The modification in calcium antagonist binding is functionally paralleled by an area specific increase in voltage-dependent calcium uptake. These data suggest that in hippocampus Substance P may be an endogenous regulator of voltage sensitive calcium channels.     

Viral fusion peptides and identification of membrane-interacting segments

Viral envelope glycoproteins promote infection by mediating fusion between viral and cellular membranes. Fusion occurs after dramatic conformational changes within fusion proteins, leading to the exposure of a short stretch of mostly apolar residues, termed the fusion peptide, which is presumed to insert into the membrane and initiate the fusion process. The typical global composition of fusion peptides, rich in hydrophobic but also in small amino acids such as alanine and glycine, was used here as bait to detect other peptidic segments that can insert into membranes. We so evidenced a similar composition in several cytotoxic peptides, which promote pore formation such as peptides involved in amyloidoses and hydrophobic alpha-hairpins of pore-forming toxins. It is suggested that the structural plasticity observed for several membrane active peptides can be conferred by this particular global amino acid composition, which could be thus used to predict such functional behavior from genome data.     

Antifungal treatment: Recent advances in dermatology.

In this paper we discuss the published relevant mycology dermatological reports which appeared in 1997 and 1998. The aims of this review is to give an actual view on antifungal therapy with a critical discussion on the efficacy of antifungals.     

hnRNP C and polypyrimidine tract-binding protein specifically interact with the pyrimidine-rich region within the 3'NTR of the HCV RNA genome

Like other members of the Flaviviridae family, the 3' non-translated region (NTR) of the hepatitis C virus (HCV) is believed to function in the initiation and regulation of viral RNA replication by interacting with components of the viral replicase complex. To inves-tigate the possibility that host components may also participate in this process, we used UV cross-linking assays to determine if any cellular proteins could bind specifically to the 3'NTR RNA. We demonstrate the specific interaction of two host proteins with the extensive pyrimidine-rich region within the HCV 3'NTR. One host protein migrates as a doublet with a molecular weight of 57 kDa and is immunoreactive with antisera specific for polypyrimidine tract-binding protein (PTB), and the other protein (35 kDa) is recognized by a monoclonal antibody specific for heterogeneous nuclear ribonucleoprotein C (hnRNP C). These results suggest that recognition of the large pyrimidine-rich region by PTB and hnRNP C may play a role in the initiation and/or regulation of HCV RNA replication.     

Native and heterologous production of bacteriocins from gram-positive microorganisms

In nature, microorganisms can present several mechanisms for setting intercommunication and defense. One of these mechanisms is related to the production of bacteriocins, which are peptides with antimicrobial activity. Bacteriocins can be found in Gram-positive and Gram-negative bacteria. Nevertheless, bacteriocins produced by Gram-positive bacteria are of particular interest due to the industrial use of several strains that belong to this group, especially lactic acid bacteria (LAB), which have the status of generally recognized as safe (GRAS) microorganisms. In this work, we will review recent tendencies in the field of invention and state of art related to bacteriocin production by Gram-positive microorganism. Hundred-eight patents related to Gram-positive bacteriocin producers have been disclosed since 1965, from which 57% are related bacteriocins derived from Lactococcus, Lactobacillus, Streptococcus, and Pediococcus strains. Surprisingly, patents regarding heterologous bacteriocins production were mainly presented just in the last decade. Although the major application of bacteriocins is concerned to food industry to control spoilage and foodborne bacteria, during the last years bacteriocin applications have been displacing to the diagnosis and treatment of cancer, and plant disease resistance and growth promotion.