R. Viviani

Metabolism of long chain fatty acids in the rumen

Publisher Summary This chapter discusses the metabolism of long-chain fatty acids in the rumen. The studies described in the chapter reveal the importance of veterinary problems in stimulating new interest in biochemical processes that might improve foods of animal origin and, thus, human nutrition. They have contributed to one of the most interesting areas of biochemical studies: the molecular basis of evolution. They have allowed the discovery of living biochemical fossils and have helped to elucidate the mechanisms of branched fatty acid biosynthesis and unsaturated fatty acid biohydrogenation. Studies on the origin of petroleum in association with studies on biological evolution show that branched-chain hydrocarbon structures derive from the corresponding fatty acid molecules. In fatty acid biohydrogenation, the enzyme responsible for the disappearance of a π bond probably represents a vestige, whose deep biological meaning is now hidden in the rumen, of the mechanisms of energy transformations of primitive organisms, when there was no oxygen in the atmosphere, at the beginning of life on earth.

Eutrophication, marine biotoxins, human health

Eutrophication phenomena in marine coastal waters can today be explained on the basis of natural or anthropogenic causes. Undesirable effects and also sanitary problems in both types of eutrophication are often produced, but they may differ greatly in frequency and significance. Some algal biotoxins can affect both marine animals and man, whilst others affect man alone. From data currently available it appears that the sanitary state of man can be affected through the digestive, respiratory and cutaneous apparatus. Four main dinoflagellate biointoxications are now recognized: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), diarrhoetic shellfish poisoning (DSP), and venerupin poisoning. Other biointoxications are due to a diatom bloom responsible for amnesic shellfish poisoning (ASP) and to blue algae blooms which have effects on the skin and the respiratory tract. All these marine toxins are considered and particular attention is paid to: producing organisms, chemistry of the components, compromised sea foods, methods of analysis, occurrence worldwide, human intoxications, toxicology and mechanism of action on a molecular level, therapeutical notes, tolerance levels and remarks on safety. Attention is also paid to the relationship between the anthropogenic eutrophication and PSP and DSP since these are the most widespread biointoxications from toxic marine dinoflagellates in the world today and for which the European Economic Community (EEC) is proposing health legislation such as tolerance limits and methods for official analysis. In view of the harmful potential of coastal anthropogenic eutrophication, the main current committment of various countries concerns control. Finally, it is important to develop a suitable monitor research system using all the specific standards of allowed toxic substances, and also research on effective antiodotes against all biotoxins.

First cases of diarrhoetic shellfish poisoning in the Northern Adriatic Sea

Shellfish poisoning occurs when toxic phytoplankton species are present in their environment. Because shellfish such as mussels are filter feeders they concentrate toxins. It is also well known that sometimes also small amounts of toxic algae can produce serious shellfish poisoning. In the Adriatic Sea, dinoflagellate red tides are a recurring phenomenon, but no shellfish poisoning has been described despite the presence of potentially toxic species such as Alexandrium spp. (Protogonyaulax) and Dinophysis spp. (...)

Inhibitors of phosphoprotein phosphatases 1 and 2A cause activation of a 53 kDa protein kinase accompanying the apoptotic response of breast cancer cells

Treatment of MCF‐7 breast cancer cells with 50 nM okadaic acid triggers an apoptotic response which is accompanied by a 7‐fold increase in the activity of a protein kinase with a relative molecular mass of 53 kDa. The activity of the kinase was stimulated by cell treatment with inhibitors of phosphoprotein phosphatase 1 and 2A, but not by stressing conditions. Okadaic acid‐induced stimulation of the 53 kDa protein kinase was not abolished by coincubation of cells with cycloheximide. We conclude that stimulation of the 53 kDa protein kinase by inhibitors of phosphoprotein phosphatases involves pre‐existing molecular components whose activity depends on the phosphorylation state of serine/threonine residues.

Fatty acids, chlorophylls and total silicon in mucilaginous aggregates collected in a coastal area of the Northern Adriatic Sea facing Emilia-Romagna in August 1988

Abstract Fatty acid, chlorophylls a , b , c and total silicon analysis were carried out in mucilaginous aggregates collected in a coastal area of the Northern Adriatic Sea facing Emilia-Romagna in August 1988, with the aim of contributing to determine the taxonomy of the producers. The combined data seem to confirm the idea that the mucilaginous aggregates mostly derive from the diatoms responsible for typical blooms in the Adriatic sea. When the presence and morphology of the organisms in the mucilaginous aggregates is not clear, the biochemical marker study seems to be useful not only for taxonomic determination of marine micro and macro algae and other eukariotic organisms, but also for marine prokariotes.

Effects of Chemical Pollutants and Phytoplankton Blooms on the Marine Biological Resources of the Adriatic Sea

The condition of the Mediterranean Sea as well as of the seas surrounding Italy, with special attention paid to the Ligurian Sea and the Upper and Middle Adriatic, raises special concerns about their pollution status. In the Upper and Middle Adriatic, in addition to the chemical pollutants (such as heavy metals and chlorinated hydrocarbons), there are also phytoplankton blooms, particularly of dinoflagellates in the coastal areas. These growths can in fact bring about effects on both the conservation of marine biological resources and on the healthy quality of fish products used for human food. This article is a review of the studies on the environmental conditions of the Adriatic Sea carried out up to this time, as well as of the role played by researchers of the Institute of Biochemistry and the University Center of Study and Research on the Marine Biological Resources of Cesenatico of the Faculty of Veterinary Medicine of the University of Bologna.

The influence of orthophosphate on nitrate reductase activity in Alexandrium sp.

The marine dinoflagellate Alexandrium sp. was isolated from the Adriatic Sea and laboratory cultures were grown in f/2-enriched seawater at initial ambient inorganic orthophosphate (SRP: soluble reactive phosphate) concentrations ranging from 0.3 to 200 μM. Under these conditions, total cellular P varied between 0.1 and 6×10 -6 moles cell -1 . Activity of nitrate reductase (NR) rose with increasing SRP concentrations, reaching maximum values at about 20 μM (...)