Metallothionein-1 and metallothionein-2 gene expression and localisation of apoptotic cells in Zn-treated LEC rat liver

The aims of the present work were to determine the effect of long-term treatment with zinc (Zn) on metallothionein (MT) concentrations and to study the levels of both MT-1 and MT-2 mRNAs in Long-Evans Cinnamon (LEC) rat liver. We also identified apoptotic cells comparing two cytochemical techniques. Thirteen rats received 50 mg zinc acetate daily by gavage, 13 rats received no treatment, and both groups were killed after 60 days. Finally four rats were killed 35 days after birth (T(0)). The results demonstrate that the Zn-treated group had higher levels of MT than both the untreated and basal ones. Quantification of mRNA indicates that the level of the Zn-treated group was significantly higher than the untreated group. Confocal fluorescent staining with monoclonal antibody (Mab) against single-strand DNA localised the hepatic cells that had chromatin condensation and nuclear fragmentation typical of apoptosis, especially in the untreated group sections. The intensity and quantity of fluorescence decreased in both the treated and basal groups. The higher sensitivity of Mab staining compared to TUNEL, which revealed both apoptotic and necrotic cells, reflects the different action mechanism of the two techniques. These findings confirm, in LEC rats, the important role of Zn in cellular protection in relation to MT expression and apoptotic processes as cellular responses to DNA damage by free radicals.     

Fatty acid content in wild type and WZSL mutant of Euglena gracilis

The effects of growth conditions on fatty acid profilewere examined in the photosynthetic wild type and inthe spontaneous non-photosynthetic WZSL mutant of theunicellular flagellate Euglena gracilis. Inthe light, the amount of polyunsaturated fatty acids(PUFAs) is higher in the wild type than in the mutant,independent of the carbon source. Among importantPUFAs, linolenic acid (18:3 3) is present inhigh amount only in wild type cells grown in the lightwith any of the tested carbon sources. The content ofother PUFAs, such as arachidonic acid (20:46), EPA (20:5 3) and DHA (22:63), is not correlated with the presence oflight or chloroplasts.The main effect of the dark in both strains is tolower the content of PUFAs and mono-unsaturated fattyacids and to increase the content of saturated fattyacids with all the carbon sources.     

Implication of tissue transglutaminase and desmoplakin in cell adhesion mechanism in human epidermis

The distribution patterns of both tissue and keratinocyte transglutaminases (TGase), as well as that of desmoplakin (DP), have been immunohistochemically investigated in human skin cultured in the absence or presence of cystamine and enalapril, two acantholytic agents. In the control samples, tissue TGase is predominantly expressed in lower layers of the epidermis and is located intercellularly. Conversely, in tissues cultured with cystamine or enalapril, a diffuse cytoplasmatic staining was observed. Similarly, DP, detected on the cell membrane in the control, shifts into the cytosol of the keratinocytes following treatment. The distribution pattern of the keratinocyte enzyme in the acantholytic epidermis was identical to that observed in the normal one. Since cystamine and enalapril are TGase inhibitors and DP was shown to act as a TGase substrate in vitro, we suggest that DP and tissue enzyme may participate in cell adhesion at the intraepidermal level.     

Rhodopsin: A Photopigment for Phototaxis in Euglena gracilis

For over 100 years, a major focus of photobiological studies has been the unicellular flagellate, Euglena gracilis, an organism well suited for such investigations by its special complement of organelles that may be considered an ancient, yet complete “visual” system. The possible photoreceptive roles of the cytoplasmic stigma and the photoreceptor (paraflagellar swelling) of E. gracilis are still under debate, because of conflicting interpretations of the results produced so far by the different research groups working on this microorganism. This article deals with our hypothesis, first put forward in the late 1980s, that rhodopsin-like proteins are responsible for photo-detection and that the paraxial rod is involved in the control of flagellar movements. This hypothesis uses oriented dipole and electroconformational coupling mechanisms as the physical phenomena that produce signal transduction. A model for phototaxis is presented.     

Vegetation of tuscan ultramafic soils in relation to edaphic and physical factors

Vegetation and soil sampling were carried out in 80 plots located in five different ultramafic (serpentine) sites of Tuscany, central Italy. The physical and chemical features of each plot were determined and the species composition and cover recorded. The exchangeable fraction of soil metals was analysed because it gives a measure of their concentrations available to plants. The plots were classified by cluster analysis and ANOVA was used to compare the environmental variables of the groups of plots. Canonical correspondence analysis was used to detect the principal factors for gradients of species composition within the plant communities. A higher content of exchangeable metals was found under the more evolved and structured plant communities, suggesting that serpentine vegetation of Tuscany is not strongly limited by soil metals, such as chromium, cobalt, nickel and magnesium, typically associated with ultramafic soils. The low nutrient content of the soils and drought stress mainly due to topographical features, appear to have a more significant role in determining the typical scattered vegetation of the Tuscan ultramafics.     

Development of a pilot scale anaerobic digester for biogas production from cow manure and whey mix

This paper presents results from anaerobic digestion of cow manure and whey mix. A pilot scale anaerobic digester, 128 l in volume, has been developed, to operate under batch and fed-batch conditions. The versatile and unique characteristics of the instrument allowed testing the methane production directly in the farm. The digester performance was evaluated with two calibration tests, the main for a period of 56 days. The study test was divided into three phases, one for each type of feeding operation (batch, fed-batch, batch). The initial phase of digestion resulted in 57 l-CH₄/kg-VS, the second phase had a yield of 86.6 l-CH₄/kg-VS and the third one had a production of 67 l-CH₄/kg-VS. The total methane yield was equal to 211.4 l-CH₄/kg-VS. Using the obtained pilot plant results to a real scale diary production cycle, it was possible to evaluate an electricity production equal to 8.86 kwh per 1 t/d. The conducted tests did show that there is a good potential to the use of a cow manure and whey biomass mix for biogas production.     

Adaptive Potential of Hybridization among Malaria Vectors: Introgression at the Immune Locus TEP1 between Anopheles coluzzii and A. gambiae in ‘Far-West’ Africa

“Far-West” Africa is known to be a secondary contact zone between the two major malaria vectors Anopheles coluzzii and A. gambiae. We investigated gene-flow and potentially adaptive introgression between these species along a west-to-east transect in Guinea Bissau, the putative core of this hybrid zone. To evaluate the extent and direction of gene flow, we genotyped site 702 in Intron-1 of the para Voltage-Gated Sodium Channel gene, a species-diagnostic nucleotide position throughout most of A. coluzzii and A. gambiae sympatric range. We also analyzed polymorphism in the thioester-binding domain (TED) of the innate immunity-linked thioester-containing protein 1 (TEP1) to investigate whether elevated hybridization might facilitate the exchange of variants linked to adaptive immunity and Plasmodium refractoriness. Our results confirm asymmetric introgression of genetic material from A. coluzzii to A. gambiae and disruption of linkage between the centromeric "genomic islands" of inter-specific divergence. We report that A. gambiae from the Guinean hybrid zone possesses an introgressed TEP1 resistant allelic class, found exclusively in A. coluzzii elsewhere and apparently swept to fixation in West Africa (i.e. Mali and Burkina Faso). However, no detectable fixation of this allele was found in Guinea Bissau, which may suggest that ecological pressures driving segregation between the two species in larval habitats in this region may be different from those experienced in northern and more arid parts of the species’ range. Finally, our results also suggest a genetic subdivision between coastal and inland A. gambiae Guinean populations and provide clues on the importance of ecological factors in intra-specific differentiation processes.