Neuroprotective Metabolites from Vietnamese Marine Derived Fungi of Aspergillus and Penicillium Genera

Low molecular weight secondary metabolites of marine fungi Aspergillus flocculosus, Aspergillus terreus and Penicillium sp. from Van Phong and Nha Trang Bays (Vietnam) were studied and a number of polyketides, bis-indole quinones and terpenoids were isolated. The structures of the isolated compounds were determined by 1D and 2D NMR and HR-ESI-MS techniques. Stereochemistry of some compounds was established based on ECD data. A chemical structure of asterriquinone F (6) was thoroughly described for the first time. Anthraquinone (13) was firstly obtained from a natural source. Neuroprotective influences of the isolated compounds against 6-OHDA, paraquat and rotenone toxicity were investigated. 4-Hydroxyscytalone (1), 4-hydroxy-6-dehydroxyscytalone (2) and demethylcitreoviranol (3) have shown significant increasing of paraquat- and rotenone-treated Neuro-2a cell viability and anti-ROS activity.     

Elucidation of the structures of residual and dissolved pine kraft lignins using an HMQC NMR technique

Comparative studies on the structures of residual and dissolved lignins isolated from pine kraft pulp and pulping liquor have been undertaken using the (1)H-(13)C HMQC NMR technique, GPC, and sugar analysis to elucidate the reaction mechanisms in kraft pulping and the lignin reactivity. A modified procedure for the isolation of enzymatic residual lignins has resulted in an appreciable decrease in protein contaminants in the residual lignin preparations (N content < 0.2%). The very high dispersion of HMQC spectra allows identification of different lignin moieties, which signals appear overlapped in 1D (13)C NMR spectra. Elucidation of the role of condensation reactions indicates that an increase in the degree of lignin condensation during pulping results from accumulation of original condensed lignin moieties rather than from the formation of new alkyl-aryl structures. Among aryl-vinyl type moieties, only stilbene structures are accumulated in lignin in appreciable amounts. Benzyl ether lignin-carbohydrate bonds involving primary hydroxyl groups of carbohydrates have been detected in residual and dissolved lignin preparations. Structures of the alpha-hydroxyacid type have been postulated to be among the important lignin degradation products in kraft pulping. The effect of the isolation method on the lignin structure and differences between the residual and dissolved lignins are discussed.     

Differentiation of soil fauna in desert agriculture of the Mariut region

Summary The soil fauna of 23 sites in the Mariut region, west of Alexandria, Egypt, was sampled monthly or seasonally for periods of 1,5–2.5 years. These sites range from unutilized littoral sand dunes, to free-grazing pasture, to low- and high-intensity dry farming, to irrigated agriculture. The average population densities of the encountered taxa were compared by corresponding analysis and by ascending hierarchic classification. With intensification of the agricultural practices, true detritivores of the original system, capable of dealing with the available plant and animal litter and adapted to the harsh desert climate, are replaced by other mesic detritivores adapted to the changes in litter quality (less animal and more plant) and also adapted to the new physical and chemical soil conditions. Meanwhile, the increase in plant biomass encourages the appearance and proliferation of cryptic phytophages (agricultural pests), occupying the niche of the removed large (domestic) herbivores. Carnivores (e.g.Carabidae) also change accordingly. Sites can thus be characterized on the basis of their soil faunas, according to the stage of their evolution, and a system of exchange of missing key taxa between sites should be established.     

Generation of self-incompatible Arabidopsis thaliana by transfer of two S locus genes from A. lyrata

Transitions from cross-fertilizing to self-fertilizing mating systems have occurred frequently in natural and domesticated plant populations, but the underlying genetic causes are unknown. We show that gene transfer of the stigma receptor kinase SRK and its pollen-borne ligand SCR from one S-locus haplotype of the self-incompatible and cross-fertilizing Arabidopsis lyrata is sufficient to impart self-incompatibility phenotype in self-fertile Arabidopsis thaliana, which lacks functional orthologs of these genes. This successful complementation demonstrates that the signaling cascade leading to inhibition of self-related pollen was maintained in A. thaliana. Analysis of self-incompatibility will be facilitated by the tools available in this species.     

Sign Change of Poisson's Ratio for Carbon Nanotube Sheets

Most materials shrink laterally like a rubber band when stretched, so their Poisson's ratios are positive. Likewise, most materials contract in all directions when hydrostatically compressed and decrease density when stretched, so they have positive linear compressibilities. We found that the in-plane Poisson's ratio of carbon nanotube sheets (buckypaper) can be tuned from positive to negative by mixing single-walled and multiwalled nanotubes. Density-normalized sheet toughness, strength, and modulus were substantially increased by this mixing. A simple model predicts the sign and magnitude of Poisson's ratio for buckypaper from the relative ease of nanofiber bending and stretch, and explains why the Poisson's ratios of ordinary writing paper are positive and much larger. Theory also explains why the negative in-plane Poisson's ratio is associated with a large positive Poisson's ratio for the sheet thickness, and predicts that hydrostatic compression can produce biaxial sheet expansion. This tunability of Poisson's ratio can be exploited in the design of sheet-derived composites, artificial muscles, gaskets, and chemical and mechanical sensors.     

Biscrolling nanotube sheets and functional guests into yarns

Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 weight percent of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, lithium-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and titanium dioxide for photocatalysis.     

Seasonal differentiation of soil mesofauna in a littoral dune of the Egyptian Mediterranean coast

Summary Soil mesofauna (sensu Ghilarov, i.e., larger than 1 mm) was sampled from under four shrub species (Lygos raetam, Thymelaea hirsuta, Lycium shawii, and Josonia candicans) growing on the littoral oolitic sand dunes at Gharbaniat, 53 km W of Alexandria, Egypt, for a period of more than 30 months, spanning 3 years. Population density (PD) was calculated in relation to area of shrub canopy. Seasons were considered, according to the prevailing climatic conditions as well as to earlier physiological studies on the animals concerned, as: four winter months, four summer months and two months for each of the transitional seasons spring and autumn. The PD values obtained for each season thus defined were combined for the 41 taxa that were sampled. The table of these data was treated by correspondence analysis (CA) and ascending hierarchic classification (AHC), by the Roux DATA-VISION programme (suitable for Apple). Results from such treatment show that fauna as related to shrub species are differentiated along the first factorial axis, while as related to seasons they are differentiated along the second axis. Taxa common to all shrubs and to all seasons are centrally placed and cause some confusion in the resolution. Summer taxa are more distantly placed than those related to the other three seasons. Fauna under Lygos is richer, more diverse, and more complementary as regards trophic levels (with predators), and could probably be the source for replenishing the fauna of the other shrubs at all seasons. The AHC method did not show a similarly clear differentiation.Dedicated to the late Prof. Dr. M.S. Ghilarov     

Sulfentrazone adsorbed on micelle-montmorillonite complexes for slow release in soil

Interactions of the herbicide sulfentrazone with the cationic surfactants octadecyltrimethylammonium (ODTMA), hexadecyltrimethylammonium (HDTMA), and benzyldimethylhexadecylammonium (BDMHDA) have been studied for the design of slow-release formulations based on sulfentrazone adsorbed on a micelle-montmorillonite complex. Adsorbed amounts of sulfentrazone on ODTMA- and BDMHDA-montmorillonite complexes were 99.2-99.8% of that added, and desorption of herbicide in water during 24 h was low. After 10 washings in funnels with soil, only 2.6% of herbicide was released from ODTMA-montmorillonite formulations versus 100% release from the commercial formulation. The strong binding of sulfentrazone to micelles was confirmed by pH and spectroscopic measurements and was explained by the formation of ionic pairs between cationic surfactant and anionic herbicide. The ODTMA-clay and commercial formulations of sulfentrazone yield almost complete and 40% growth inhibition of green foxtail, respectively, at 700 g of active ingredient/ha. Hence, the slow release from micelle-clay formulations of sulfentrazone promotes its biological activity and reduces environmental contamination.     

Stimulated esophageal groove closure in adult goats

In healthy adult goats, closure of the esophageal groove was induced by thirst, IV administered vasopressin, and intracarotid administration of hypertonic NaCl solutions. The efficiency of stimulation was tested directly by visual inspection of the course taken by orally administered solutions through a ruminal or abomasal fistula, palpation of the lips of the esophageal groove through a ruminal fistula, and indirectly by following the glucose dynamics in the blood after oral administration of glucose solution. Esophageal groove closure was observed during drinking after a 48-hour period of water deprivation. Intracarotid administration of 1.5 ml of a saturated solution or 10.5 ml of a 1.5% solution of NaCl also stimulated groove closure; however, groove closure stimulated by administration of vasopressin is the most satisfactory procedure for passing compounds of therapeutic importance directly from the cardiac orifice to the abomasum.