Localization of ribosomal genes and nucleolar activity in lymphocytes of swine (Sus scrofa domestica) stimulated by phytohemagglutinins

The Pig chromosomes that contain rDNA sites displayed a polymorphism in the distribution of the genes among the nucleolar organizers located on pairs Nos. 8 and 10. Two, or more often three, active sites were observed in the chromosomes of lymphocytes stimulated with phytohemagglutinin. Only 5% of the metaphases showed a 4th small active site. At the onset of stimulation most cells contained one-two nucleoli; four nucleoli were never observed. After prolonged stimulation, the number of nuclei containing three nucleoli increased. A 4th small nucleolus appeared in a few cells, presumably formed by activation of the smallest rDNA site.     

Morpho-colorimetric characterization by image analysis to identify diaspores of wild plant species

Digital images of ex situ germplasm stored in the Sardinian Germplasm Bank (BG-SAR) were used for the application of image analysis techniques at the Stazione Sperimentale di Granicoltura per la Sicilia. The analysed accessions refer to 148 taxonomic units belonging to 102 genera and 47 families, typical of the Sardinian flora, and of the Mediterranean basin in general.The images of diaspores were acquired by a flatbed scanner and elaborated with a macro specially developed for the morphometric and colorimetric measurements. This method allowed carrying out a database for the characterization of autochthonous germplasm in entry to the bank and the realization of statistic classifiers for the discrimination of genera and species within the following families: Apiaceae, Boraginaceae, Caryophyllaceae, Cistaceae, Fabaceae and Scrophulariaceae. Such classifiers, based on the linear discriminant analysis (LDA) technique and checked by cross-validation, showed a performance included between 74.3% and 96.4%.In addition, for the genus Astragalus, it was possible to elaborate a classifier able to identify very similar taxa of a species complex, obtaining a performance between 83.7% and 100%. Such analysis proved the validity of the methodology also from the taxonomic point of view.Suggestions for subsequent methodological progress, which could offer applications in other research issues, such as ecological analysis, soil seed bank and archaeological botany are proposed.     

Intrauterine programming of ageing

Ageing is an unavoidable corollary to being alive; the most intuitive interpretation of ageing being that it is the consequence of progressive body degeneration. In agreement with this, current models propose that ageing occurs through a stepwise accumulation of DNA damage, which ultimately limits the regenerative capacity of tissues. On the other hand, there is increasing evidence that fetal distress can influence the development of disease in adult life, a phenomenon known as ‘intrauterine programming’. The extent to which an intrauterine exposure to DNA damage can compromise lifespan remains unclear. My group has recently generated a murine model of a human syndrome linked to defective DNA repair and observed that these animals age prematurely, but the accumulation of DNA damage is restricted mostly to the embryonic period. Here, I discuss the implications of this finding and propose that ageing can be influenced by fetal distress.     

JAR human placental choriocarcinoma cells actively synthesize,take up and release polyamines

Uptake of polyamines has been investigated extensively in many cells, but not in placenta, where the polyamine– polyamine oxidase system is supposed to have an immunoregulatory function in pregnancy. Due to the importance of the transfer in this tissue, we have started this study. JAR human placental choriocarcinoma cells in monolayer at confluency were used as a model for measuring the key enzymes of polyamine synthesis and interconversion, rate of uptake and efflux, and the polyamine content. Polyamines were taken up by JAR cells and released by an independent mechanism. Ornithine decarboxylase and spermidine acetyltransferase activities and the rate of transport in and out of the cell were much higher than in other cells, such as L1210 cells. However the systems used for uptake and release appear in many respects to be similar to those observed in L1210 cells, but different from others. The uptake appears to be regulated by an inhibitory protein. Moreover, protein kinase C appears to be involved in the process. The efflux also is regulated as in L1210 cells, through control of H⁺ and Ca²⁺ concentration. In conclusion, this study shows that, in JAR cells, ornithine decarboxylase and spermidine acetyltransferase activities were much higher than in other cells, and so was the rate of transport in and out of the cells. As a result, a much higher polyamine content was observed.     

DNA damage in stomach, kidney, liver and lung of rats treated with atrazine

The genotoxic activity of atrazine, a widely used triazine herbicide, was assayed by the DNA alkaline elution technique in rats given orally a single high dose or repeated daily doses. DNA breaks (and/or alkali-labile lesions) were detected in cell suspensions obtained from stomach, kidney and liver, but not in those from lung.     

Effect of ciprofibrate on the activation and oxidation of very long chain fatty acids

The effect of ciprofibrate, a hypolipidemic drug, was examined in the metabolism of palmitic (C_16:0) and lignoceric (C_24:0) acids in rat liver. Ciprofibrate is a peroxisomal proliferating drug which increases the number of peroxisomes. The palmitoyl-CoA ligase activity in peroxisomes, mitochondria and microsomes from ciprofibrate treated liver was 3.2, 1.9 and 1.5-fold higher respectively and the activity for oxidation of palmitic acid in peroxisomes and mitochondria was 8.5 and 2.3-fold higher respectively. Similarly, ciprofibrate had a higher effect on the metabolism of lignoceric acid. Treatment with ciprofibrate increased lignoceroyl-CoA ligase activity in peroxisomes, mitochondria and microsomes by 5.3, 3.3 and 2.3-fold respectively and that of oxidation of lignoceric acid was increased in peroxisomes and mitochondria by 13.4 and 2.3-fold respectively. The peroxisomal rates of oxidation of palmitic acid (8.5-fold) and lignoceric acid (13.4-fold) were increased to a different degree by ciprofibrate treatment. This differential effect of ciprofibrate suggests that different enzymes may be responsible for the oxidation of fatty acids of different chain length, at least at one or more step(s) of the peroxisomal fatty acid -oxidation pathway.     

Occurrence of oscillations in ATP synthesis and hydrolysis in chromatophores of Rhodospirillum rubrum

The conditions under which an oscillatory behaviour is observed during net hydrolysis or synthesis of ATP in chromatophores of Rhodospirillum rubrum FR1 are described. In the case of ATPase the oscillations are observed at low temperature (ca. 11°C) in the dark after an initial transient behaviour. These oscillations are attenuated or disappear by the addition of an uncoupler.Oscillations are also observed during ATP synthesis. At 3°C the oscillations appear spontaneously if photophosphorylation is measured during a sufficiently long time. At 30°C the mere intercalation of a dark period also at 30°C is sufficient to trigger the oscillations in the following light period.Abbreviations Bchl Bacteriochlorophyll - FCCP carbonyl cyanide p-trifluoromethoxyphenyl hydrazone - PMS phenazine methosulfate - TMPD, N,N,N,N tetramethyl-1,4-phenylenediamine Dedicated to Prof. Dr. Gerhart Drews as a homage for his permanent example as hard worker and careful scientist and also for his remarkable human quality