Induced gene expression in wheat seedlings treated with a crude extract of Agapanthus africanus L. prior to leaf rust infection

It was previously shown that a crude extract of Agapanthus africanus L. (Hoffman), applied as a foliar spray to wheat (Triticum aestivum L.) seedlings, significantly increased the in vitro activities of three pathogenesis related (PR) proteins (β-1,3-glucanase, chitinase and peroxidase). This was the case in both susceptible and resistant wheat lines whether the plants were uninfected or infected with leaf rust (Puccinia triticina). The aim of this study was to determine the influence of the A. africanus extract on both the intercellular PR-protein profile and PR gene expression in leaf rust infected wheat lines. Pretreatment of infected resistant and susceptible wheat with the extract led to increased β-1,3-glucanase levels that were higher as compared to the untreated controls. Similarly, treatment with the extract led to greater expression of both the PR3 and PR9 genes in infected resistant and susceptible seedlings as compared to the controls. This is also applied to a retrotransposon protein encoding gene whose expression was strongly induced following extract treatment. The induced expression of all these defence-related genes suggests that the crude A. africanus extract has the ability to prime the resistance response of wheat prior to leaf rust infection.Keywords: Wheat leaf rust, induced resistance, priming, gene expression, immunoblotting, crude Agapanthus africanus extractAfrican Journal of Biotechnology Vol. 12(20), pp. 2876-288

Evaluation of Greenbug and Yellow Sugarcane Aphid Feeding Behavior on Resistant and Susceptible Switchgrass Cultivars

Switchgrass (Panicum virgatum L.) is an emerging biofuel crop that serves as host for aphids. To discern the effects of plant age and possible resistance mechanisms, the feeding behavior of greenbugs (Schizaphis graminum Rondani.) and the yellow sugarcane aphid (Sipha flava Forbes.) was monitored on three diverse switchgrasses by the electrical penetration graph (EPG) technique. Callose deposition and genes associated with callose metabolism were also analyzed to discern their association with plant resistance. There was a strong host effect on greenbugs feeding on lowland cultivar Kanlow at the V3 stage of development, as compared to the greenbug-susceptible upland cultivar Summer and plants derived from Kanlow (♂) × Summer (♀) (K×S) crosses. These data confirmed that Kanlow at the V3 stage had antibiosis to greenbugs, which was absent in the Summer and K×S plants. In contrast, similar effects were not observed for yellow sugarcane aphids, excluding significant differences in the time to first probe on Kanlow plants at the V1 stage and reduction in time spent on pathway processes on Kanlow plants at the V3 stage. These data demonstrated that Kanlow plants may have multiple sources of resistance to the two aphids, and possibly some were phloem based. Microscopy of leaf sections stained with aniline blue for callose was suggestive of increased callose deposition in the sieve elements in Kanlow plants relative to Summer and K×S plants. RT-qPCR analysis of several genes associated with callose metabolism in infested plants was equivocal. Overall, these studies suggest the presence of multiple defense mechanisms against aphids in Kanlow plants, relative to Summer and K×S plants

Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation

The mammals of Angola

Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to be associated with unique physiographic settings such as the Angolan Escarpment. The mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11 Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio

Establishment of embryogenic suspension cultures of Pinus radiata Don: research note

The development of embryonal suspensor mass (ESM) from immature embryos of Pinus radiata on a solidified growth medium containing 0, 5 mgl -1 benzyladenine, 3, 0 mgl -1 2, 4-dichlorophenoxyacetic acid, 500 mgl -1 casein hydrolysate and 250 mgl -1 L-glutamine was used as inoculum to establish cell suspension cultures. Regular transplants of the ESM established on the solidified medium onto a hormone-free medium ensured sustainable growth and hence a source of ESM. Conditions for optimal growth in liquid media were investigated. The cell suspension turbidity was measured and used as a growth parameter. Optimal growth and normal embryo development were obtained in a liquid medium containing maltose as the carbohydrate source at a concentration of 3% (m/v) and supplemented with 0, 5 mgl -1 2, 4- dichlorophenoxyacetic acid. The results obtained from this study present an opportunity for large-scale propagation of Pinus radiata . Southern African Forestry Journal No.194 2002: 53-5

Diffusion Coefficient of Naphthalene in Air, Carbon Dioxide and Helium.

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Vapour Phase Mass Transfer Coefficient of Naphthalene in Structured Packing.

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Evaluation of Evaporative Emissions from Gasoline Powered Motor Vehicles under South African Conditions

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Indicators of sustainable fishing for South African sardine Sardinops sagax and anchovy Engraulis encrasicolus

Six indicators were investigated for South African sardine Sardinops sagax and anchovy Engraulis encrasicolus: mean length of catch, length-at-50% maturity, total mortality, exploitation rate, ratio of bycatch, and centre of gravity of commercial catches. Sardine length-at-50% maturity is the most promising as a descriptive indicator because it is positively correlated with population size for an extensive time period (1953–2005). The remaining indicators were limited by shorter data-series (1984–2005). However, mean length of catch, ratio of bycatch and exploitation rate were found to be useful when considered in conjunction with other indicators. The centre of gravity of commercial sardine catches has shown a significant eastward shift from the West Coast, whereas that of anchovy has remained off that coast. Ratio of bycatch indicates that school composition is a reliable descriptive indicator of relative abundance in the two species. Fewer indicators for anchovy were useful, which is attributed to this species' flexible life-history pattern. Keywords: anchovy; biological indicator; exploitation; maturity; pelagic; sardineAfrican Journal of Marine Science 2006, 28(3&4): 661–68