Mangroves diversity and erosion mitigation performance in a low salinity soil area: case study of Vinh City,Vietnam

Wetlands Ecology and Management - This study aims to investigate the diversity of mangrove species and their soil erosion mitigation performance in Hung Hoa Mangrove Forest, Vinh City, Vietnam....     

Polyisoprenylated benzophenone and xanthone constituents of the bark of Garcinia cochinchinensis

A new polyisoprenylated benzophenone, guttiferone T, three other benzophenones, (?)-30-epi-cambogin, (?)-guttiferone G and (?)-garcinialiptone A, together with six xanthones, tovophyllin B, nigrolineaxanthone V, pedunxanthone A, tovophyllin A, parvifolixanthone B and dulxanthone A, were isolated from the bark of Garcinia cochinchinensis. Their structures were elucidated using spectroscopic methods, mainly 1-D and 2-D NMR. Three of the polyisoprenylated benzophenone were tested for their cytotoxicity towards two human cancer cell lines, Hela and MCF-7, and exhibited weak activity.     

Molecular Basis for Genetic Resistance of Anopheles gambiae to Plasmodium: Structural Analysis of TEP1 Susceptible and Resistant Alleles

Thioester-containing protein 1 (TEP1) is a central component in the innate immune response of Anopheles gambiae to Plasmodium infection. Two classes of TEP1 alleles, TEP1*S and TEP1*R, are found in both laboratory strains and wild isolates, related by a greater or lesser susceptibility, respectively to both P. berghei and P. falciparum infection. We report the crystal structure of the full-length TEP1*S1 allele which, while similar to the previously determined structure of full-length TEP1*R1, displays flexibility in the N-terminal fragment comprising domains MG1-MG6. Amino acid differences between TEP1*R1 and TEP1*S1 are localized to the TED-MG8 domain interface that protects the thioester bond from hydrolysis and structural changes are apparent at this interface. As a consequence cleaved TEP1*S1 (TEP1*S1_cut) is significantly more susceptible to hydrolysis of its intramolecular thioester bond than TEP1*R1_cut. TEP1*S1_cut is stabilized in solution by the heterodimeric LRIM1/APL1C complex, which preserves the thioester bond within TEP1*S1_cut. These results suggest a mechanism by which selective pressure on the TEP1 gene results in functional variation that may influence the vector competence of A. gambiae towards Plasmodium infection.     

Cophylogenetic analysis of the relationship between anemonefish Amphiprion (Perciformes: Pomacentridae) and their symbiotic host anemones (Anthozoa: Actiniaria)

ABSTRACT

The association between anemonefish and anemone is a classical example of mutualism in coral reefs. Although mutualism is probably the key innovation that triggered the adaptive radiation of anemonefish into a wide range of habitats, the coevolutionary history between the groups has not been thoroughly tested in a phylogenetic framework. We examined the evolutionary history of the association via distance-based (Parafit and PACo) and event-based methods (Core-PA, Jane). Mitochondrial DNA sequences (COI mtDNA, Cytb, 16S rDNA and 12S rDNA) were used to reconstruct the phylogenies of tropical Amphiprion species and their host anemones by using maximum likelihood with best-fit models selected. Neither distance-based analyses nor event-based analyses revealed global significant congruence between the phylogenies of the hosts and the symbionts, and thus no evidence for coevolution between anemone-anemonefish. However, at the individual pair level, the fish showed some dependence on anemone hosts. Even though living in close association and benefiting from each other, the change of genetic composition of one species (anemonefish) does not always evolve in response to changes in the other (anemones). These findings expand our understanding of the pattern and the role of evolutionary events to allow a better prediction of the future of the anemonefish-anemone relationship.     

Filamentous vibriophage fs2 encoding the rstC gene integrates into the same chromosomal region as the CTX phage [corrected]

The genome of the filamentous phage of Vibrio cholerae fs2 was found to contain rstC and rstB1 (truncated) genes downstream of ORF500. att-fs2-dir and att-fs2-rev sequences homologous to that of att-CTXphi were found between orf500 and rstC of the fs2 genome. This prompted us to search for the integration site of fs2 in the genomes of V. cholerae O1 and O139. The genome of fs2 was found to integrate downstream of attRS of the CTXphi phage, which integrated into chromosome I of V. cholerae O1 and O139. When infected with fs2, a fimbriate strain of V. cholerae O1 appeared to reduce fimbrial production in an adult rabbit ileal loop assay.     

Design,Synthesis and Biological Activities of New Pyrazole Derivatives Possessing Both Coxib and Combretastatins Pharmacophores

In our efforts to discover novel multi‐target agents having better antitumor activities than celecoxib, 21 new aryl‐substituted pyrazole derivatives possessing cis‐diphenylethylene scaffold were mostly synthesized by a one‐pot approach to ethyl 1,4,5‐triaryl‐1H‐pyrazole‐3‐carboxylates via an improved Claisen condensation – Knorr reaction sequence. The cytotoxic effects of these compounds against three human cancer cell lines HT‐29, Hep‐G2, MCF‐7 as well as their inhibition of NO production were studied. Results showed that incorporation of the important pharmacophoric groups of two original molecules celecoxib and combretastatin A‐4 in a single molecule plays an important role in determining a better biological activities of the new coxib‐hybrided compounds.     

Potential role of SH groups in the radiosensitivity of adenylate cyclase

The role of oxidation of SH groups in the activity of adenylate cyclase and in radiosensitivity of the enzyme was investigated. Adenylate cyclase activity was measured in purified membrane preparation of 19 day old chicken embryo brains. N-ethyl-maleimide (NEM) and lead-acetate were used as SH inhibitors. Gamma irradiation was carried out with 60-Co source. NEM inhibition of adenylate cyclase was dose dependent and 50 per cent inhibition was observed at 40-50 microM NEM. Activity of adenylate cyclase was elevated at lower concentrations of lead-acetate (10 nM-100 microM) and was inhibited at higher concentrations (above 100 microM). The presence of 40 microM NEM did not alter the shape of lead acetate saturation curve of adenylate cyclase. Gamma irradiation in the dose range of 100-800 Gy elevated the adenylate cyclase activity measured in the presence of 5 mM NaF but did not alter the basal activity. Gamma irradiation did not have significant effect on NEM saturation of adenylate cyclase, while it altered slightly the lead acetate saturation curve.     

Two different mechanisms of ampicillin resistance operating in strains of Vibrio cholerae O1 independent of resistance genes

Autoagglutinable strains of Vibrio cholerae O1 (seven nonfimbriate strains and one fimbriate strain) were transformed to obtain resistance to ampicillin. Two distinct mechanisms were found in these strains. One was operating in nonfimbriate strains by reducing OmpU protein production and the other was operating in a fimbriate strain (Bgd17) by newly overproducing cpxP protein. The twitching motility in the fimbriate Bgd17 strain disappeared depending on the production of cpxP protein, suggesting that fimbriation of V. cholerae O1 is controlled by a two-component signal transduction system.