First evidence of immunomodulation in bivalves under seawater acidification and increased temperature

Water acidification, temperature increases and changes in seawater salinity are predicted to occur in the near future. In such a global climate change (GCC) scenario, there is growing concern for the health status of both wild and farmed organisms. Bivalve molluscs, an important component of coastal marine ecosystems, are at risk. At the immunological level, the ability of an organism to maintain its immunosurveillance unaltered under adverse environmental conditions may enhance its survival capability. To our knowledge, only a few studies have investigated the effects of changing environmental parameters (as predicted in a GCC scenario) on the immune responses of bivalves. In the present study, the effects of both decreased pH values and increased temperature on the important immune parameters of two bivalve species were evaluated for the first time. The clam Chamelea gallina and the mussel Mytilus galloprovincialis, widespread along the coast of the Northwestern Adriatic Sea, were chosen as model organisms. Bivalves were exposed for 7 days to three pH values (8.1, 7.7 and 7.4) at two temperatures (22 and 28°C). Three independent experiments were carried out at salinities of 28, 34 and 40 PSU. The total haemocyte count, Neutral Red uptake, haemolymph lysozyme activity and total protein levels were measured. The results obtained demonstrated that tested experimental conditions affected significantly most of the immune parameters measured in bivalves, even if the variation pattern of haemocyte responses was not always linear. Between the two species, C. gallina appeared more vulnerable to changing pH and temperature than M. galloprovincialis. Overall, this study demonstrated that climate changes can strongly affect haemocyte functionality in bivalves. However, further studies are needed to clarify better the mechanisms of action of changing environmental parameters, both individually and in combination, on bivalve haemocytes.     

A comparison of genome modifications leading to genetic and epigenetic tumorous transformation in Nicotiana spp. tissue cultures

A single system is presented, where both genetic and epigenetic control of tumor induction can be studied at the same time. This system is offered by the amphidiploid tumorous hybrid Nicotiana glauca × N. langsdorffii, a nontumorous mutant of it and the nontumorous parent species N. glauca and N. langsdorffii. The aim of the present paper is to compare long-term in vitro cultures of tumorous (genetic and habituated), and nontumorous strains, through the characterization of their genomes according to several physico-chemical parameters. The data reported show that both qualitative and quantitative differences in DNA complexity are correlated with the tumorous transformation. Particularly, a high degree of mismatching between the DNAs of the tumorous and nontumorous hybrids and the lack, in the second genotype (nontumorous), of three DNA peaks in Ag⁺?Cs²SO⁴ analytical ultracentrifugation profile seem to support the hypothesis, suggested in a previous paper, of the presence, in the nontumorous mutant, of a gross chromosomal rearrangement, probably a deletion. Amplification and underreplication of specific sequences also seemed to be correlated with changes from the normal to the tumorous state, highly repetitive sequences being present in higher amounts in the normal strains and in the habituated N. glauca than in the case of the tumorous hybrid. Finally, DNA bound ion contents were found to be strikingly higher in tumorous than in nontumorous tissues. The results are discussed in the frame of the general hypothesis of high somatic genomic plasticity in plants.     

Conformational behaviour of A cyclolinopeptide a analogue: Two-dimensional NMR study of cyclo(Pro1-Pro-Phe-Phe-Ac6c-IIe-ala-Val8)

The cyclic octapeptide cyclo[-Pro¹-Pro-Phe-Phe-Ac₆c-Ile-ala-Val⁸-] [C₈-Ac₆c], containing the Pro¹-Pro-Phe-Phe sequence, followed by a bulky helicogenic C^α,α-dialkylated glycine residue Ac₆c (1-aminocyclohexane-1-carboxylic acid), and a _D-Ala residue at position 7 has been synthesized. This cyclic peptide is a deletion analogue of the naturally occurring cyclic nonapeptide cyclolinopeptide A (CLA). It has been designed with the aim of studying the role that the Ac₆c and _D-Ala residues play on the conformational behaviour of the whole molecule and their influence on the conformation of the Pro¹-Pro-Phe-Phe sequence when compared with cyclolinopeptide A. C₈Ac₆c has been investigated in chloroform and acetonitrile solutions by 2D NMR techniques. Only one set of sharp signals is observed in both solvents. This evidence strongly supports the hypothesis that only one conformational state exists in the chosen solvents. The interpretation of the experimental data points to the existence for C₈-Ac₆c of a very rigid structure stabilized by intramolecular hydrogen bonds. The measured NOE effects allow the calculation of internuclear distances, which have been used as restraints in molecular dynamic calculations. The proposed conformation of the molecule shows that the Pro-Pro-Phe segment retains the conformation observed in natural CLA both in solution and in the solid state and that the Ac₆c residue indeed reinforces the ring rigidity not permitting the formation of any appropriate cavity in which inorganic cations could be complexed.     

Non-steroidal anti-inflammatory drugs react with two sites on platelet cyclo-oxygenase evidence from ‘in vivo’ drug interaction studies in rats

Non-steroidal anti-inflammatory drugs inhibit platelet cylco-oxygenase activity. This study shows that salicylate, diflunisal, sulphinpyrazone and indomethacine prevent in vivo aspirin inhibitory effect of cyclo-oxygenase activity as measured by the formation of malondialdehyde and thromboxane B₂, two products of platelet arachidonic acid metabolism. Salicylate also prevents the inhibitory effect of indomethacin. All these drugs therefore appear to interact with the same site on platelet cyclo-oxygenase. Since salicylate is inactive by itself on this platelet enzyme and diflunisal and sulphinpyrazone were used at ineffective doses, it is suggested that their interaction with aspirin (or indomethacin) occurs at the level of a supplementary site is necessary but not sufficient for the efficacy of these drugs as cyclo-oxygenase inhibitors. Acetylation by aspirin of the active site appears to be a phenomenon secondary to the binding of salicylate moiety to the supplementary site.     

On the double nature of productivity in inflectional morphology

Inflection is generally considered to be more productive than derivation. To justify such an assumption, the syntactic function of inflectional morphology is contrasted with the mainly lexical function of derivational morphology. In this paper, the whole question will be carefully discussed with the help of recently developed quantitative approaches to productivity. On the basis of data taken from Italian, it will be shown that a quantitative approach to productivity can shed light on this intricate question by revealing the double nature of inflectional morphology, which on the one hand sides with derivational morphology because of its lexically conditioned inflectional classes. On the other, it scores very high productivity rates for the single inflectional categories in accordance with its syntactic function. Furthermore, the productivity rates of the inflectional categories considered are shown to be not uniform: several factors may influence their productivity, as for instance the substitutive usage of periphrases with modals, even in a language like Italian in which the latter are far less grammaticalized than in others. Parts of this paper were presented at the XI International Morphology Meeting held in Vienna, 14th–17th February 2004, and in lectures given at the Universities of Graz, L’Aquila, Marburg, Roma Tre, and Salerno. I wish to express my gratitude to the people who discussed with me the ideas contained in the paper, and in particular to my colleague and friend Davide Ricca, who has been sharing with me the pleasure and the hard work of conducting quantitative investigations on Italian morphology. Many ideas contained in the paper are the result of constant and animated discussions with him. Finally, I am very much indebted to the editor Ingo Plag and two anonymous reviewers for remarkable observations and comments. Needless to say, I carry the full responsability for errors and misunderstandings contained in the paper.     

Prostacyclin and human foetal circulation.

Tissues from human umbilical cord arteries and placental veins generated much greater prostacyclin activity than vessels from normal adults. High prostacyclin generation could contribute to maintaining the low peripheral vascular resistance typical of foetal circulation in which blood pressure is low despite very high cardiac output.