Induction of systemic resistance toColletotrichum falcatum in sugarcane by a synthetic signal molecule, acibenzolar-S-Methyl(CGA-245704)

The effect of a novel synthetic signal molecule, acibenzolar-S-methyl (CGA-245704; benzo [1,2,3] thiadiazole-7-carbothioic acid S-methyl ester), in inducing resistance in sugarcane against red rot disease caused by the fungusColletotrichum falcatum Went was studied. Application of CGA-245704 as a soil drench or along with marcotting rooting mixture induced resistance in sugarcane to challenge inoculation withC. falcatum. When the pathogen was inoculated by the plug method, it caused discoloration in the untreated control stalk tissues; however, in the stalk tissues pretreated with acibenzolar-S-methyl, pathogen colonization was considerably reduced. When the pathogen was inoculated by nodal swabbing, its penetration was arrested in the sensitized stalk tissues. An induced systemic resistance effect was found to persist up to 30 days in the pretreated cut canes. Increased phenolic content and accumulation of pathogenesis-related (PR) proteins,viz., chitinase, β-1,3-glucanase and thaumatin-like protein (PR-5), were observed in sugarcane plants treated with acibenzolar-S-methyl.     

Efficacy of medicinal plant extracts against Formosan subterranean termite, Coptotermes formosanus

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is among the most devastating termite pests. Natural products derived from plant extracts were tested in a discovery programme for effective, environment friendly termite control agents. Screening for anti-termitic activity of plant extracts with some known medicinal attributes could lead to the discovery of new agents for termite control. The aim of this study was to investigate the anti-termitic activity of crude leaf hexane, ethyl acetate, acetone and methanol extracts of Andrographis lineata Wallich ex Nees. (Acanthaceae), Andrographis paniculata (Burm.f.) Wall. ex Nees. (Acanthaceae), Argemone mexicana L. (Papaveraceae), Aristolochia bracteolata Lam. (Aristolochiaceae), Datura metel L. (Solanaceae), Eclipta prostrata L. (Asteraceae), Sesbania grandiflora (L.) Pers. (Fibaceae) and Tagetes erecta L. (Compositae) against C. formosanus. An impregnated filter paper no-choice bioassay method was followed. All the crude extracts showed anti-termitic activity in a dose-dependent manner and exhibited a significant activity after 24 h and 48 h of exposure; the highest termite mortality was found in leaf hexane extract of A. bracteolata, ethyl acetate extract of A. paniculata, D. metel, E. prostrata, methanol extract of A. lineata and D. metel after 24 h (LD₅₀ = 363, 371, 298, 292, 358 and 317 ppm; LD₉₀ = 1433, 1659, 1308, 1538, 1703 and 1469 ppm), respectively. The hexane extract of T. erecta, acetone extract of A. mexicana, methanol extract of S. grandiflora and T. erecta showed activity after 48 h (LD₅₀ = 245, 253, 289, 409 ppm; LD₉₀ = 1378, 1511, 1508 and 2425 ppm), respectively. Among the natural products tested, may provide a renewable source of safe natural wood preservatives. These findings corroborate traditional insecticidal application of selected plants and the results can be extended for the control of termites. The primary objective of the present study was to identify novel, natural chemotypes from biologically active crude plant extracts that may be useful as part of termite treatment regimens in their natural form or as synthons for structure-activity studies in the future. The results reported here open the possibility of further investigations of efficacy on their anti-termitic properties of natural product extracts.     

Dough Strain Hardening Properties as Indicators of Baking Performance

Bread loaf volume is an important economic criterion. Breeders, millers, and bakers need measurements allowing them to evaluate dough performance during processing. Strain hardening is an important dough property. It describes the stability of the gas cell walls and the ability of cells to expand further; therefore, the higher the strain hardening index (n), the better the baking performance. Dough exhibits strain hardening during uniaxial extensibility tests. However, obtaining n from an extensibility test is time consuming. The objectives of this study were to identify the extensibility parameters that contribute to n. Three parameters were retained in the model (R² = 0.90): dough strength (R_max), extensional delay (E_Diff), and initial slope of the curve (E_i). R_max was the largest contributor and was proportional to the dough strain hardening properties. E_Diff and E_i had a detrimental effect on n. The appropriateness of the model was validated with two sample sets (19 genotypes, 12 environments). Significant correlations were found between loaf volume and n (r = 0.52–0.64) for 7 of the 12 environments. The strain hardening index was found to be a good predictor for baking performance as judged by loaf volume.     

Postcolumn Fluorimetric HPLC Procedure for Determination of Niacin Content of Cereals

Analytical procedures for determining niacin or vitamin B3 content of foods are tedious, require large quantities of toxic chemicals, and are timeconsuming. In addition, food matrices are difficult as samples because of their complex nature. A selective, sensitive HPLC technique was developed with postcolumn derivatization as well as fluorescence and spectroscopic detection systems. Niacin was separated and retained for 6.5 min on a polymeric column with an aqueous mobile phase containing sodium acetate buffer. A postcolumn system consisting of a stainless-steel pump and reaction coil allowed detection and quantitation of niacin. An acid-enzyme sample-extraction method was most compatible with HPLC and postcolumn derivatization with 5% each of acidified p-aminophenol and cyanogen bromide. Lower detection limit and mean recovery were 3.6 ng and 99.43%, respectively. Fluorescence response for nicotinamide was half that of nicotinic acid. A lower response for nicotinamide was also noted with conventional spectroscopy. However, the new method yielded comparable values for six of eight ready-to-eat commercial cereal samples. No significant difference was observed between the AACC reference and HPLC fluorimetric methods. Chemical derivatization was done within a reaction coil with reagents at half strength, limiting exposure to hazards and minimizing waste-disposal problems.