Cowpea weevil bioassay: A simple prescreen for plants with grain protectant effects

Abstract

Peasant farmers in northern Nigeria indigenously use various plants to protect cereals and legumes against pest damage during storage. We have developed and employed a simple bioassay technique to assess plants for their ability to protect cowpea from damage by weevil during storage. Of the 10 plants screened, Hyptis suaveolens Poit. (Labiatae) and Sphenoclea zeylanica G earth (Sphenocleacea) showed the best protectant effects after 4 months. The details of the bioassay procedure used and the results obtained are reported.     

Role of adaptor TRIF in the MyD88-independent toll-like receptor signaling pathway

Stimulation of Toll-like receptors (TLRs) triggers activation of a common MyD88-dependent signaling pathway as well as a MyD88-independent pathway that is unique to TLR3 and TLR4 signaling pathways leading to interferon (IFN)-beta production. Here we disrupted the gene encoding a Toll/IL-1 receptor (TIR) domain-containing adaptor, TRIF. TRIF-deficient mice were defective in both TLR3- and TLR4-mediated expression of IFN-beta and activation of IRF-3. Furthermore, inflammatory cytokine production in response to the TLR4 ligand, but not to other TLR ligands, was severely impaired in TRIF-deficient macrophages. Mice deficient in both MyD88 and TRIF showed complete loss of nuclear factor kappa B activation in response to TLR4 stimulation. These findings demonstrate that TRIF is essential for TLR3- and TLR4-mediated signaling pathways facilitating mammalian antiviral host defense.     

An unusual form of lipid linkage to the CD45 peptide

Some protein kinases and phosphatases are myristoylated on their amino terminus, which perhaps contributes to subcellular localization or regulation. Glycoprotein CD45, a hematopoietic tyrosine phosphatase, was examined for fatty acid content. The CD45 protein incorporated [3H]myristate, but little [3H]palmitate. The label was not metabolized and reincorporated into amino acids or saccharides, as revealed by peptide maps of CD45 labeled with [3H]myristate, 14C-labeled amino acids, [35S]methionine, or 125I, and glycosidase treatments, respectively. The myristate label was resistant to mild alkaline methanolysis and was found in fatty acid and sphingosine, indicating an unusual form of lipid attachment to CD45.     

Lack of exposed ice inside lunar south pole Shackleton Crater

The inside of Shackleton Crater at the lunar south pole is permanently shadowed; it has been inferred to hold water-ice deposits. The Terrain Camera (TC), a 10-meter-resolution stereo camera onboard the Selenological and Engineering Explorer (SELENE) spacecraft, succeeded in imaging the inside of the crater, which was faintly lit by sunlight scattered from the upper inner wall near the rim. The estimated temperature of the crater floor, based on the crater shape model derived from the TC data, is less than approximately 90 kelvin, cold enough to hold water-ice. However, at the TC's spatial resolution, the derived albedo indicates that exposed relatively pure water-ice deposits are not on the crater floor. Water-ice may be disseminated and mixed with soil over a small percentage of the area or may not exist at all.     

Influence of Physicochemical Properties of Starch on Crispness of Tempura Fried Batter

The influence of the physicochemical properties of heat‐moisturetreated and untreated starches from various plant sources on the quality of tempura fried batter was examined. Batter of each starch plus wheat protein (92:8, w/w) was fried. Quality of the resulting fried batter was determined from crispness score, water evaporation, and breaking strength. The crispness score correlated with water evaporation (r = 0.95) and breaking strength (r = 0.97), indicating that water evaporation was a reliable index for evaluation of crispness of fried batter. Determination of water evaporation was easy and simple. The crispness (favorable eating texture) of tempura coating depended largely on starch origin. Among the pasting properties of starch, temperature at maximum viscosity (r = 0.77) and breakdown/maximum viscosity (% breakdown, r = ‐0.82) correlated with water evaporation, suggesting that starch resistant to gelatinization and granule disintegration produced crispy fried batter. This observation was supported by SEM. Water evaporation (r = ‐0.82) and % breakdown (r = 0.95) correlated with degree of amylose gelatinization, indicating that amylose was one of the determinants that controls crispness of fried batter by restraining disintegration of the starch granule structure.     

Molecular Structure and Some Physicochemical Properties of Buckwheat Starches

The molecular structure and pasting properties of starches from eight buckwheat cultivars were examined. Rapid viscograms showed that buckwheat starches had similar pasting properties among cultivars. The actual amylose content was 16–18%, which was lower than the apparent amylose content (26–27%), due to the high iodine affinity (IA) of amylopectin (2.21–2.48 g/100 g). Amylopectins resembled each other in average chain‐length (23–24) and chain‐length distributions. The long‐chains fraction (LC) was abundant (12–13% by weight) in all the amylopectins, which was consistent with high IA values. The amyloses were also similar among the cultivars in number‐average DP 1,020–1,380 with 3.1–4.3 chains per molecule. The molar‐based distribution indicated that all the amyloses comprised two molecular species differing in molecular size, although the weight‐based distribution showed a single species. A comparison of molecular structures of buckwheat starches to cereal starches indicated buckwheat amylopectins had a larger amount of LC, and their distributions of amylose and short chains of amylopectin on molar basis were similar to those of wheat and barley starches.     

Fine Structures of Amylose and Amylopectin from Large,Medium, and Small Waxy Barley Starch Granules

Amylose and amylopectin were prepared from large, medium, and small granule starches of classified waxy barley flour, and their fine structures were investigated. The amylose content had a wide distribution range (≈1.4–9.4%). Number‐average degrees of polymerization (DP_n) of the amyloses were similar among the samples (≈1,200–1,300). But number of chains per molecule (NC) decreased from the surface to the center (≈6–10 chains). DP_n of the amylopectins varied from 4,657 to 14,604; decreased in the order of large, medium, and small granules in same fractions of the grain; and increased from the surface layer to the center. Longest chains (LC) were not found in any of the amylopectin molecules. The large amylopectin molecule had more long chains and fewer A chains than the small molecule. The amylose content had definite effects on the transition temperature range and crystal formation of the starch granules. There were positive correlations between DP_n of the amylopectin and relative crystallinity (γ = +0.69) and enthalpy value (γ = +0.80), respectively. These findings may help to elucidate biosynthesis mechanism of starch.