Long-term evolutionary stability of bacterial endosymbiosis in curculionoidea: additional evidence of symbiont replacement in the dryophthoridae family

Bacterial intracellular symbiosis (endosymbiosis) is well documentedin the insect world where it is believed to play a crucial rolein adaptation and evolution. However, although Coleopteran insectsare of huge ecological and economical interest, endosymbiontmolecular analysis is limited to the Dryophthoridae family.Here, we have analyzed the intracellular symbiotic bacteriain 2 Hylobius species belonging to the Molytinae subfamily (Curculionoideasuperfamily) that exhibit different features from the Dryophthoridaeinsects in terms of their ecology and geographical spanning.Fluorescence in situ hybridization has shown that both Hylobiusspecies harbor rod-shaped pleiomorphic symbiotic bacteria inthe oocyte and in the bacteria-bearing organ (the bacteriome),with a shape and location similar to those of the Dryophthoridaebacteriome. Phylogenetic analysis of the 16S ribosomal DNA genesequences, using the heterogeneous model of DNA evolution, hasplaced the Hylobius spp. endosymbionts (H-group) at the basalposition of the ancestral R-clade of Dryophthoridae endosymbiontsnamed Candidatus Nardonella but relatively distant from theS-clade of Sitophilus spp. endosymbionts. Endosymbionts fromthe H-group and the R-clade evolved more quickly compared withfree-living enteric bacteria and endosymbionts from the S- andD-clades of Dryophthoridae. They are AT biased (58.3% A + T),and they exhibit AT-rich insertions at the same position aspreviously described in the Candidatus Nardonella 16S rDNA sequence.Moreover, the host phylogenetic tree based on the mitochondrialCOI gene was shown to be highly congruent with the H-group andthe R-clade, the divergence of which was estimated to be around125 MYA. These new molecular data show that endosymbiosis isold in Curculionids, going back at least to the common ancestorof Molytinae and Dryophthoridae, and is evolutionary stable,except in 2 Dryophthoridae clades, providing additional andindependent supplementary evidence for endosymbiont replacementin these taxa.     

Towards Enhancing Community Health in El-Fayoum,Egypt, Using Ecosystem Approaches

Ecosystem degradation caused by factors such as improper natural resources management and contamination with agricultural, industrial, and domestic wastes often results in the creation of an unhealthy ecosystem, a main cause for the prevailing poverty and poor health in many parts of rural Egypt. In collaboration with members of the community in some villages of El-Fayoum province, an interdisciplinary research team is currently employing an ecosystem approach to arrive at an understanding of community health problems with a view to develop resource management interventions and policies aimed at enhancing community health and well-being. Participatory rural appraisal (PRA) and knowledge, attitudes, and practices (KAP) techniques were used to measure the perceptions of the community’s men and women of their health and environmental priorities, and to test their current state of knowledge and awareness of the health-related issues. The results indicate that these perceptions were gender-sensitive and were different from those of Ministry of Health. Spatial and temporal monitoring and assessment of the ecosystem components revealed considerable land and water resources degradation. Presence of water pools and waterways in the vicinity of the residential areas enhanced the risk of water-associated diseases. Although, the disease-carrying vectors of schistosomiasis and malaria were detected in the waterways, the incidence of the two diseases was relatively low in the main village in contrast to the situation in the nearby hamlets. Prevalence of schistosomiasis was substantially higher in these hamlets (20–30% compared to 2–3% in the main village). Such a highly infected community represents a continuous pool of reinfection of the waterways, an issue that needs to be further examined to determine its relation to the hamlets’ specific ecosystem characteristics. A high incidence of hepatitis C and soil transmitted-intestinal parasites were markedly detected. It is concluded that in addition to natural resources degradation, other potential health risk factors were identified including socioeconomic, cultural, and institutional factors. Further studies are being conducted to explore these potential risk factors and their links to human health and well-being.     

2-Substituted 4-, 5-, and 6-[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones and 2-substituted 4,5-bis[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones as potent platelet aggregation inhibitors: design, synthesis, and SAR studies

A set of regioisomeric 2-substituted pyridazin-3(2H)-ones containing a 3-oxo-3-phenylprop-1-en-1-yl fragment at either position 4, 5 or 6 and 2-substituted pyridazin-3(2H)-ones containing the same fragment both at positions 4 and 5 have been synthesized and evaluated as antiplatelet agents. The study allows the identification of a new highly potent platelet aggregation inhibitor (4c).     

Synthesis and activity on rat aorta rings and rat pancreatic beta-cells of ring-opened analogues of benzopyran-type potassium channel activators

Ring-opened analogues of dihydrobenzopyran potassium channel openers (PCOs) were prepared and evaluated as putative PCOs on rat aorta rings (myorelaxant effect) and rat pancreatic beta-cells (inhibition of insulin secretion). These derivatives are characterized by the presence of a sulfonylurea, a urea or an amide function. Some compounds bearing an arylurea moiety provoked vasorelaxant effects and a marked inhibition of insulin release. Derivatives bearing a sulfonylurea or an amide function were, however, poorly active on both tissues. Structure-activity relationships and apparent tissue selectivity are discussed.     

In vitro effect of metal ions on the activity of two amphibian glyceraldehyde-3-phosphate dehydrogenases: potential metal binding sites

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) was purified from two amphibian species, Xenopus laevis and Pleurodeles waltl. Comparative studies revealed that the two proteins differ by their subunit molecular masses, pI values and V8 digested peptide maps. The effect of zinc, cadmium and copper ions on GAPDH enzymatic activity has been examined in vitro. A time, metal concentration and metal type dependent inhibition was observed for both enzymes. X. laevis and P. waltl GAPDHs exhibit a much greater sensitivity to copper than to cadmium or zinc ions. Different half-lives and differential sensitivity to various metals was observed between the two enzymes with P. waltl GAPDH being remarkably tolerant to cadmium ions compared to the X. laevis enzyme. In order to understand the differential sensitivity of the two enzymes to metals, we produced 3D models of both X. laevis and P. waltl GAPDH structures based upon known 3D structures of GAPDHs from other species. This necessitated, in a first step, to clone a 900 bp cDNA fragment encoding the nearly full-length P. waltl GAPDH. Spatial motif searches on the homology models indicated potential metal binding sites involving cysteine and histidine residues outside the catalytic sites, existing only in either the X. laevis or the P. waltl GAPDH sequences.     

Recovery of development and functionality of nodules and plant growth in salt-stressed Pisum sativum--Rhizobium leguminosarum symbiosis by boron and calcium

Nodules developed in Pisum sativum L. cv. Argona inoculated with Rhizobium leguminosarum bv. viciae 3841 and growing under saline conditions (75 mmol/L NaCl) are non functional and had abnormal structure. The infected cells contained a low amount of endophytic bacteria, compared to treatments without salt. Addition of B (up to 55.8 μmol/L) and Ca²⁺ (up to 2.72 mmol/L) increased bacterial population of host plant cells in salt-stressed nodules. Furthermore, symbiosomes developed inside the nodules from salt treated plants presented a degraded peribacteroid membrane. This effect was also prevented by combined addition of B and Ca²⁺. Given the importance of both nutrients in cell wall structure, the pectin fraction was studied by electron microscopy and immunological methods. Salt stress produced cells with walls dramatically altered or even degraded in several zones. Pectin polysaccharides, detected by JIM 5 monoclonal antibody, increased in cells under salinity. These effects resembled typical effects of B-deficiency reactions in cell walls, and the increase of both Ca²⁺ and especially B also prevented these alterations.     

A novel autosomal recessive non-syndromic deafness locus, DFNB66, maps to chromosome 6p21.2-22.3 in a large Tunisian consanguineous family

Hereditary non-syndromic deafness is extremely heterogeneous. Autosomal recessive forms account for approximately 80% of genetic cases. Autosomal recessive non-syndromic sensorineural deafness segregating in a large consanguineous Tunisian family was mapped to chromosome 6p21.2-22.3. A maximum lod score of 5.36 at theta=0 was obtained for the polymorphic microsatellite marker IR2/IR4. Haplotype analysis defined a 16.5-Mb critical region between microsatellite markers D6S1602 and D6S1665. The screening of 3 candidate genes, COL11A2, BAK1 and TMHS, did not reveal any disease causing mutation, suggesting that this is a novel deafness locus, which has been named DFNB66. A search in the Human Cochlear EST Library for ESTs located in this critical interval allowed us to identify several candidates. Further investigations on these candidates are needed in order to identify the deafness-causing gene in this Tunisian family.     

Interaction of intermittent fasting on the cytotoxic effects of nickel in rats at puberty

This study has been undertaken with the aim of determining if intermittent fasting can be considered as a malnutrition that amplifies, according to numerous authors, the cytotoxic effects of environmental pollutants. We have used 200 male and female rats of 'Wistar' descent (BW approximately 180 g). These rats are distributed into two groups: some nourished daily (N) and others nourished one day over two (J) during a month. By the end of this month, each group is itself split into two subgroups, the first one receiving tap water as drinkable water (group NO and JO); the other one receiving the water enriched by the chloride of nickel at the rate of 100 mg NiCl2 per litre (groups NNi and JNi). Intermittent fasting goes on parallel to treatment during 2, 4, 10, 16, 30 and 60 days. For the exploration of the protein of stress (HSP) and of the metallothioneines (MT), the nickel is administered by injection at the rate of 4 mg NiCl2 per kg during 1 and 5 days. Our results show that the mineral seric and renal balance does not vary in conditions of intermittent fasting compared with conditions of normal nutrition. Our study show than that nickel induced a renal deficiency by decreasing the creatinemia and uraemia rate, which is confirmed by the histological study, and induced a decrease in the induction of the HSP73 and in the synthesis of the (MT). The association of nickel with intermittent fasting would inhibit these effects. In conclusion, intermittent fasting does not manifest itself as a malnutrition that amplifies the nickel's effects. Nevertheless, it seems that the calorific lack provoked by intermittent fasting is beneficial to the body by increasing its performances against the cytotoxic effects induced by nickel.     

Association of PON1 and PON2 Polymorphisms with PON1 Activity and Significant Coronary Stenosis in a Tunisian Population

PON1 and PON2 have attracted considerable attention as candidate genes for coronary heart disease because their enzymes function as key factors in lipoprotein catabolism pathways. We studied the distribution of PON1 and PON2 polymorphisms, including genotyping, lipid profile, and PON1 activity, and their association with PON1 activity and significant coronary stenosis (SCS) in a Tunisian population. PON1 activity was lower in patients with SCS than in controls. It increased with the R allele (QQ < QR < RR) in PON1-192 genotypes and with the L allele (MM < ML < LL) in PON1-55 genotypes. In the presence of metabolic syndrome and diabetes, PON1-192RR and PON2-311CC were associated with an increased risk of SCS and PON1-55MM seems to have lower risk. This association was evident among nonsmokers for PON1-55MM and among smokers for PON1-192RR and PON2-311CC. The GTGC haplotype seemed to increase the risk of SCS compared with the wild haplotype in a Tunisian population.