Regional localization of th human EGF-like growth factor CRIPTO gene (TDGF-1) to chromosome 3p21

The CRIPTO gene encodes a novel human growth factor structurally related to epidermal growth factor. We localized the CRIPTO gene to chromosome 3p21 by fluorescence in situ hybridization with a cosmid clone containing 40 kb of the CRIPTO genomic region (TDGF-1). To suppress hybridization to CRIPTO-related sequences, present in multiple copies in the human genome, hybridization was carried out in the presence of unlabeled CRIPTO cDNA in excess over the probe. Our finding confirms the provisional mapping of the CRIPTO gene to chromosome 3, and assigns it precisely to a chromosomal region involved in several rearrangements occurring in malignancy.CRIPTO-specific sequences are present in multiple copies in the human genome (Dono et al. 1991). Two genomic CRIPTO-encoding sequences, TDGF-1 and TDGF-3, have been isolated and characterized. TDGF-1 corresponds to the structural gene encoding the protein expressed in teratocarcinoma cells (Ciccodicola et al. 1989). TDGF-3, possibly a functional pseudogene, corresponds to a complete copy of the TDGF-1 mRNA that contains seven base changes representing both silent and replacement substitutions in the coding region (Dono et al. 1991). By somatic cell hybrid analysis TDGF-1 has been assigned to chromosome 3, and TDGF-3 to the Xq21–22 region (Dono et al. 1991).     

Structural and functional aspects of the respiratory chain of synaptic and nonsynaptic mitochondria derived from selected brain regions

Studies on brain mitochondria are complicated by the regional, cellular, and subcellular heterogeneity of the central nervous system. This study was performed using synaptic and nonsynaptic mitochondria obtained from cortex, hippocampus, and striatum of male Sprague-Dawley rats (3 months old). Ubiquinone content, detected by HPLC analysis, was about 1.5 nmol/mg protein with an approximate CoQ₉/CoQ₁₀ molecular ratio of 2:1. The activities of several respiratory chain complexes were also studied (succinate-cyt.c reductase, NADH-cyt.c reductase, succinate-DCIP, ubiquinol₂-cyt.c reductase, and cytochrome oxidase), and generally found to be higher in mitochondria from cortex than from other regions. Study of the activities of some of these enzymes vs. 1/T (Arrhenius plots) showed a straight line with an activation energy between 7 and 10 kcal/mol in all the three areas considered. Only CoQ₂H₂-cyt.c reductase activity revealed a biphasic temperature dependence. Also anisotropy (as fluorescence polarization) of the hydrophobic probe DPH showed a deviation from linearity; the break points for both enzymatic activity and anisotropy were found at about 23–24°C.     

The flocculation of wine yeasts: biochemical and morphological characteristics inZygosaccharomyces — flocculation inZygosaccharomyces

The floc-forming ability of flocculent strains ofZygosaccharomyces bailii andZ fermentati, isolated from musts, was tested for susceptibility to proteinase and sugar treatments.Z. fermentati was found highly resistant to the proteolytic enzymes tested, whereasZ. baili was only trypsin-resistant.The inhibition of flocculation by sugars distinguished two types: inZ. fermentati flocculation was completely inhibited by mannose, inZ. bailli by various sugars.By SEM observation, the cell surface ofZygosaccharomyces revealed the presence of a column structure, resulting from fusion of vesicles present on the cell surface.     

The anthropogenically stressed periphyton of Lake Orta,Italy

A long history of discharge of industrial wastes has left Lake Orta contaminated with high concentrations of acid, ammonia and copper. To study the effect of this chronic pollution on periphyton, I sampled epilithic algae and associated invertebrates at several sites from 1987 to 1988. Although biomass varied both spatially and seasonally, the taxonomic composition of these communities remained relatively stable. The dominant algae were chlorophytes and the dominant invertebrates were trichopterans. Comparisons with nearby unpolluted Lake Mergozzo, and with general equations developed for neutral lakes in North America indicate that these anthropogenic stresses are more clearly reflected by changes in the taxonomic composition and size distribution of the community than by changes in its biomass.Contribution No 375 from the Groupe de recherches en Ecologie des Eaux douces, Université de Montréal.Contribution No 375 from the Groupe de recherches en Ecologie des Eaux douces, Université de Montréal.     

The effect of fetch on periphyton spatial variation

The marked spatial variation in periphyton could reflect differences in exposure, grazing or substratum. To determine if any of these factors was significant, I studied the relationship between the degree of exposure to waves (measured as fetch), grazing intensity (measured as invertebrate biomass) and spatial variation in periphyton biomass in sites of similar substratum along an island in the central mesotrophic basin of Lake Memphremagog (Québec). In spring, there was a positive relationship between fetch and periphyton biomass both on stones and on artificial substrata. This effect was especially strong for diatoms, for algae between 100–1000 µm³, for planktonic forms and for filamentous and long-stalked species. In spring, water renewal encouraged growth of these forms, but the effect disappeared in summer, coincident with silica depletion. Grazers, which were not important in the spatial variation observed in spring, probably contributed to the sudden decline of periphyton in the exposed sites in summer. Observations in nearby lakes indicate that these patterns may be general.Contribution of the Lake Memphremagog Project, Limnology Research Centre.     

Sporadic cases in Duchenne muscular dystrophy

Summary A new estimation of the proportion of sporadic cases in Duchenne muscular dystrophy was attempted by means of segregation analysis in a sample of 988 sibships collected on a world-wide scale by different authors. Maximum likelihood estimates of ascertainment probability (), segregation frequency (p), and frequency of sporadic cases (x) were calculated by Morton's equations under different hypotheses. The best fit was found for p=0.454±0.024 and x=0.235±0.034. The possibility that the proportion of sporadic cases might be lower than the expected 1/3 is suggested.     

Double-stranded RNA

Summary High molecular weight, fully double-stranded RNA (dsRNA) has been recognized as the genetic material of many plant, animal, fungal, and bacterial viruses (Diplomaviruses); virus-specific dsRNA is also found in cells infected with single-stranded RNA viruses.DsRNA has been identified in a variety of apparently normal eucaryotic cells and is associated with the killer character of certain strains of Saccaromyces cerevisiae.The properties and significance of these various dsRNA species are described and discussed, as well as the available information concerning the biosynthesis of such RNA in virus-infected cells, its degradation by a variety of enzymes, and some problems concerning the variables which may control this process.Finally, the biological functions of dsRNA are briefly considered, as well as the structural properties important for its activity as an inducer of interferon and an inhibitor of protein synthesis.Abbreviations dsRNA for double-stranded RNA - ssRNA for single-stranded RNA - SSC for 0.15 m sodium chloride, 0.015 m sodium citrate, pH 7 - Poly(A), poly(C), poly(U) for polyadenylate, polycytidylate and polyuridylate, respectively - Poly(A).poly(U), poly(G).poly(C), poly(I).poly(C) for double-stranded complexes formed between polyadenylate and polyuridylate, polyguanylate and polycytidylate, and polyinosinate and polycytidylate, respectively. - Poly(rA).poly(dT) for the complex formed between polyriboadenylate and polydeoxyribothymidylate - Poly(A-U), poly(G-C) for the alternating copolymers containing AMP and UMP, or GMP and CMP, respectively - Poly(rA).poly(dUz) for the complex formed between polyadenylate and poly 2-azido-2deoxyuridylate - (I)_n.(br⁵C)_n for the complex formed between polyinosinate and poly 5-bromocytidylate - (I)_n.(s²C)_n for the complex formed between polyinosinate and poly 2-thiocytidylate - (dI_n3)_n.(C)_n for the complex formed between poly 2-azido-2-deoxyinosinate and polycytidylate - MW for molecular weight     

Effect of arachidonic, eicosapentaenoic and docosahexaenoic acids on the oxidative status of C6 glioma cells

n-3 polyunsaturated fatty acids (PUFAs) have been described to have beneficial effects on brain development and in the prevention and treatment of brain damage. C6 glioma cells were incubated with 100 microM of either C20:4n-6 (ARA), or C20:5n-3 (EPA), or C22:6n-3 (DHA) for different time periods to assess whether these acids altered the cellular oxidative state. The ARA and EPA were promptly metabolised to C22:4n-6 and C22:5n-3, respectively, whereas DHA treatment simply increased the amount of DHA in the cells. Cell viability was not affected by ARA, while a cytotoxic effect was observed 72 h after n-3 PUFAs supplementation. The levels of reactive oxygen species and thiobarbituric acid-reactive substances were significantly higher in DHA-treated cells than in EPA- and ARA-treated groups. This modification in the oxidative cellular status was also highlighted by a significant increase in catalase activity and a decrease in glutathione content in DHA-supplemented cells. Glucose-6-phosphate dehydrogenase activity, an enzyme involved in redox regulation, and O2*- release were significantly increased both in EPA and DHA groups. The effect of DHA was more severe than that of EPA. No significant changes were observed in the ARA group with respect to untreated cells. These data show that EPA and DHA induce alterations in the oxidative status that could affect the glial function.     

Protective effect of capsinoid on lipid peroxidation in rat tissues induced by Fe-NTA

The activity of a single IP administration (15 or 30 mg/Kg body weight) of vanillyl nonanoate, a simplified analog of capsiate, on ferric nitrilotriacetate (Fe-NTA)-mediated oxidative damage was investigated. A sub-lethal dose of Fe-NTA (15 mg Fe/Kg body weight) was administered IP to rats; animals were sacrificed, and kidney and plasma were collected 1 h after injection. In response to the Fe-NTA administration, a reduction of the levels of total lipids, total unsaturated fatty acids and cholesterol was observed, accompanied by a rise in the concentrations of malondialdehyde (MDA), conjugated dienes fatty acids hydroperoxides and 7-ketocholesterol in plasma and kidney 1 h after administration. A pre-treatment with synthetic capsiate (SCPT) showed remarkable protective effect on the reduction of the levels of total lipids, total unsaturated fatty acids and cholesterol, and the cellular antioxidant vitamin E, inhibiting the increase of MDA, conjugated dienes fatty acids hydroperoxides and 7-ketocholesterol in the plasma and kidney. The protective effect of SCPT and two analogues (vanillyl alcohol and vanillin) during the linoleic acid and cholesterol oxidation was investigated in in vitro systems, providing evidence of definite structure-activity relationships.     

Development of new procedures for the isolation of phytoplankton DNA from fixed samples

Phytoplankton samples collected for routine monitoring programmes have traditionally been preserved with fixatives before subsequent analytical procedures such as microscope-based identification, or simply to permit transport between laboratories. In recent years, to simplify identification and enumeration, the use of DNA or RNA probes coupled with the PCR assay has progressed and now represents a routine procedure for screening cultured and field samples. However, the phytoplankton cells have often still to be treated as fixed samples.The extraction of genomic DNA from fixed cultures of Alexandrium minutum cultures was compared using two new methods based on Magnetisable Solid Phase Support (MSPS) techniques with that using three commercial kits. Genomic DNA recovery and PCR amplification were observed and the results obtained from culture samples were validated using field samples. Among the DNA extraction techniques considered, the MSPS methods provided the best results.