Identification,Evolutionary Patterns and Intragenic Recombination of the Gametophytic Self Incompatibility Pollen Gene (SFB) in Tunisian Prunus Species (Rosaceae)

Plant Molecular Biology Reporter - Plum (Prunus L.) is a species which exhibits a gametophytic self-incompatibility system “GSI” as the majority of species belonging to the Rosaceae...     

Synthesis and biological activity of chloroethyl pyrimidine nucleosides

The synthesis and biological activity of chloroethyl pyrimidine nucleosides is presented. One of these new nucleosides analogues significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.     

Synthesis and biological activity of mustard derivatives of thymine

The synthesis and biological activity of a novel DNA cross-linking antitumor agent is presented. The new alkylating agent significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.     

Endocrine-related reproductive effects in molluscs

Research on endocrine disruption has been a major topic of the past decade. Although most studies concentrated on vertebrate species, invertebrates are now gaining more attention. In particular, data on molluscs is increasing. One of the best-documented and more relevant examples of endocrine disruption is the imposex phenomenon affecting some gastropod species. But the increasing interest is also due to the fact that molluscs, especially bivalves, are good bioindicators used for decades in environmental studies and that progress have been made in the understanding of the physiology and endocrinology of some mollusc species. Recent results suggest that molluscs can be adversely affected by compounds that alter their reproduction and that vertebrate-type sex-steroids metabolism or mechanism of action could be involved in these effects. Nevertheless, the endocrine system of molluscs appears to be dissimilar in many aspects to those of vertebrates and sex-steroids might not have the same importance in all mollusc species. This diversity constitutes an important opportunity to examine and understand new and alternative mechanisms for endocrine disruption.     

Caldicoprobacter algeriensis sp. nov. a New Thermophilic Anaerobic, Xylanolytic Bacterium Isolated from an Algerian Hot Spring

A thermophilic anaerobic bacterium (strain TH7C1(T)) was isolated from the hydrothermal hot spring of Guelma in the northeast of Algeria. Strain TH7C1(T) stained Gram-positive, was a non-motile rod appearing singly, in pairs, or as long chains (0.7-1 × 2-6 μm(2)). Spores were never observed. It grew at temperatures between 55 and 75°C (optimum 65°C) and at pH between 6.2 and 8.3 (optimum 6.9). It did not require NaCl for growth, but tolerated it up to 5 g l(-1). Strain TH7C1(T) is an obligatory heterotroph fermenting sugars including glucose, galactose, lactose, raffinose, fructose, ribose, xylose, arabinose, maltose, mannitol, cellobiose, mannose, melibiose, saccharose, but also xylan, and pyruvate. Fermentation of sugars only occurred in the presence of yeast extract (0.1%). The end-products from glucose fermentation were acetate, lactate, ethanol, CO(2), and H(2). Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate, and sulfite were not used as electron acceptors. The G+C content of the genomic DNA was 44.7 mol% (HPLC techniques). Phylogenetic analysis of the small-subunit ribosomal RNA (rRNA) gene sequence indicated that strain TH7C1(T) was affiliated to Firmicutes, order Clostridiales, family Caldicoprobacteraceae, with Caldicoprobacter oshimai (98.5%) being its closest relative. Based on phenotypic, phylogenetic, and genetic characteristics, strain TH7C1(T) is proposed as a novel species of genus Caldicoprobacter, Caldicoprobacter algeriensis, sp. nov. (strain TH7C1(T) = DSM 22661(T) = JCM 16184(T)).     

Immunomodulatory Effects of Four Leishmania infantum Potentially Excreted/Secreted Proteins on Human Dendritic Cells Differentiation and Maturation

Leishmania parasites and some molecules they secrete are known to modulate innate immune responses through effects on dendritic cells (DCs) and macrophages. Here, we characterized four Leishmania infantum potentially excreted/secreted recombinant proteins (LipESP) identified in our laboratory: Elongation Factor 1 alpha (LiEF-1α), a proteasome regulatory ATPase (LiAAA-ATPase) and two novel proteins with unknown functions, which we termed LiP15 and LiP23, by investigating their effect on in vitro differentiation and maturation of human DCs and on cytokine production by DCs and monocytes. During DCs differentiation, LipESP led to a significant decrease in CD1a. LiP23 and LiEF-1α, induced a decrease of HLA-DR and an increase of CD86 surface expression, respectively. During maturation, an up-regulation of HLA-DR and CD80 was found in response to LiP15, LiP23 and LiAAA-ATPase, while an increase of CD40 expression was only observed in response to LiP15. All LipESP induced an over-expression of CD86 with significant differences between proteins. These proteins also induced significant IL-12p70 levels in immature DCs but not in monocytes. The LipESP-induced IL-12p70 production was significantly enhanced by a co-treatment with IFN-γ in both cell populations. TNF-α and IL-10 were induced in DCs and monocytes with higher levels observed for LiP15 and LiAAA-ATPase. However, LPS-induced cytokine production during DC maturation or in monocyte cultures was significantly down regulated by LipESP co-treatment. Our findings suggest that LipESP strongly interfere with DCs differentiation suggesting a possible involvement in mechanisms established by the parasite for its survival. These proteins also induce DCs maturation by up-regulating several costimulatory molecules and by inducing the production of proinflammatory cytokines, which is a prerequisite for T cell activation. However, the reduced ability of LipESP-stimulated DCs and monocytes to respond to lipopolysaccharide (LPS) that can be observed during human leishmaniasis, suggests that under certain circumstances LipESP may play a role in disease progression.     

Phylogenetic Analysis and Epidemic History of Hepatitis C Virus Genotype 2 in Tunisia,North Africa

HCV genotype 2 (HCV-2) has a worldwide distribution with prevalence rates that vary from country to country. High genetic diversity and long-term endemicity were suggested in West African countries. A global dispersal of HCV-2 would have occurred during the 20^th century, especially in European countries. In Tunisia, genotype 2 was the second prevalent genotype after genotype 1 and most isolates belong to subtypes 2c and 2k. In this study, phylogenetic analyses based on the NS5B genomic sequences of 113 Tunisian HCV isolates from subtypes 2c and 2k were carried out. A Bayesian coalescent-based framework was used to estimate the origin and the spread of these subtypes circulating in Tunisia. Phylogenetic analyses of HCV-2c sequences suggest the absence of country-specific or time-specific variants. In contrast, the phylogenetic grouping of HCV-2k sequences shows the existence of two major genetic clusters that may represent two distinct circulating variants. Coalescent analysis indicated a most recent common ancestor (tMRCA) of Tunisian HCV-2c around 1886 (1869–1902) before the introduction of HCV-2k in 1901 (1867–1931). Our findings suggest that the introduction of HCV-2c in Tunisia is possibly a result of population movements between Tunisia and European population following the French colonization.     

Mitochondrial DNA and Alzheimer’s disease: a first case–control study of the Tunisian population

Molecular Biology Reports - Alzheimer’s disease (AD) is the most common neurodegenerative disorder in humans and presents a major health problem throughout the world. The etiology of AD is...