Flavonoid increase in soybean as a response to Nezara viridula injury and its effect on insect-feeding preference

The ability of the stink bug (Nezara viridula) to induce and/or increase production of chemical defenses, i.e., flavonoids, in immature seeds of five genotypes of soybean (BR-16, IAC-100, PI 227687, PI 229358, and PI 274454) was investigated under greenhouse and laboratory conditions. Samples from pods of each genotype damaged by stink bug were analyzed for flavonoid content with high performance liquid chromatography. A dual-choice test was conducted to evaluate the feeding preference of N. viridula comparing BR-16 pods treated with extracts of PI 227687 seeds (with and without stink-bug injury), with water-treated pods. Seeds of PI 227687 damaged by N. viridula presented the highest concentration (352 g/g) of daidzin (4-hydroxyisoflavone-7-glucoside). The same trend was observed with genistin (4,5,7-trihydroxyisoflavone-7-glucoside): PI 227687 contained 142.4 g/g, PI 274454, 31.6 g/g, and PI 229358, 38.9 g/g. Seeds damaged by stink bugs had higher isoflavone contents (daidzin and genistin), compared to controls. However, after being damaged, PI 274454 and PI 229358 produced less genistin than the other genotypes and no differences in concentration between damaged and nondamaged plants of this genotypes were observed. The numbers of observations of the insect feeding and the numbers of stylet sheaths left in water-treated BR-16 pods were greater than in those treated with PI 227687 extracts. The insects fed for longer periods on BR-16 pods treated with extract of PI 227687 without injury compared to those that were treated with extract of PI 227687 previously injured by stink bugs. Extracts of PI 227687 pods (damaged or not) were deterrent to adults of N. viridula, and insect injury increased concentrations of daidzin and genistin in PI 227687 seeds. The deterrence seemed to be more pronounced after pods had suffered stink-bug injury.     

On sequential frame synchronization in AWGN channels

We present a framework for the analysis of frame synchronization based on synchronization words (SWs), where the detection is based on the following sequential algorithm. The received samples are observed over a window of length equal to the SW; over this window, a metric (e.g., correlation) is computed; an SW is declared if the computed metric is greater than a proper threshold, otherwise the observation window is time-shifted one sample. We assume a Gaussian channel, antipodal signaling, equally distributed data symbols, and coherent detection, where soft values are provided to the frame synchronizer. We state the problem starting from the hypothesis testing theory, deriving the optimum metric [optimum likelihood ratio test (LRT)] according to the Neyman-Pearson lemma. When the data distribution is unknown, we design a simple and effective test based on the generalized LRT (GLRT). We also analyze the performance of the commonly used correlation metric, both with "hard" and "soft" values at the synchronizer input. We show that synchronization can be greatly improved by using the LRT and GLRT metrics instead of correlation and that, among correlation-based tests, sometimes hard correlation is better than soft correlation. The obtained closed-form expressions allow the derivation of the receiver operating characteristic (ROC) curves for the LRT and GLRT synchronizers, showing a remarkable gain with respect to synchronization based on correlation metric.     

Determination of lycopene, α- and β-carotene and retinyl esters in human serum by reversed-phase high performance liquid chromatography

A rapid specific, microdetermination of the major human blood carotenoids by high performance liquid chromatography (HPLC) separation and quantitation at 466 nm is detailed in this paper. Serum retinyl esters can also be quantified utilizing the same separation procedure but detected at 325 nm. One hundred microliters of deproteinated serum were extracted with chloroform and injected on a reverse-phase column. Separation occurred within 16 min for all compounds of interest employing a mobile solvent of MeOH/AcN/CHCl₃ (47∶47∶6). All compounds were quantified at the wavelengths cited by integrated peak areas using retinyl acetate as a daily standard. Analysis of serum from a hypercarotenemic anorexia nervosa patient and a person suffering from hypervitaminosis A are presented as examples of the clinical application of this procedure.     

Mycobacterium sp., Rhodococcus erythropolis, and Pseudomonas putida behavior in the presence of organic solvents

This work aimed at studying the behavior and tolerance of Mycobacterium sp. NRRL B-3805, Rhodococcus erythropolis DCL14 and Pseudomonas putida S12 cells in the presence of various concentrations of water miscible (ethanol, butanol, and dimethylformamide, up to 50% v/v) and water immiscible solvents (dodecane, bis(2-ethylhexyl) phthalate and toluene, up to 5% v/v). When incubated in the presence of these solvents, the cells were found to have lower tolerance to butanol and toluene than to the remaining solvents. Nevertheless, the concentrations of solvents endured by the tested strains show that they are quite solvent-tolerant, confirming their potential as biocatalysts in nonconventional systems. Microscopic observation of samples showed that the hydrophobic Mycobacterium sp. and R. erythropolis cells were able to aggregate to protect the population under stress conditions. Comparison of the results obtained at the single cell level by fluorescence microscopy and colony development on agar plates indicated that the primary effects of most solvents tested were on the cell membrane and replicating capability of the cells.     

Genotypic and technological characterization of enterococci isolated from artisanal Fiore Sardo cheese

A total of 118 enterococcal strains isolated from artisanal Fiore Sardo cheese were characterized technologically and genetically. The presence of potential virulence factors was also investigated. Strains were classified as Ec. faecium (84 strains), Ec. durans (24 strains) and Ec. faecalis (10 strains). RAPD-PCR analysis with two different primers (M13 and XD9) confirmed species identification and proved useful for the detection of interstrain variations, especially among Ec. faecium isolates. Most strains could hydrolyse casein and had weak acidifying activity in milk. None of the isolates produced lipolytic reactions. Gelatinase activity was observed in two strains of Ec. faecalis and one strain of Ec. durans. beta-Haemolysis on horses' blood was never detected in any of the strains, independently of species. Most strains produced tyramine from tyrosine but none decarboxylated lysine, histidine or ornithine. Overall, a wide spectrum of resistance was observed. Almost all strains were resistant to the aminoglycosides, gentamycin, kanamycin, streptomycin, neomycin, and to the semisynthetic penicillin, oxacillin, but resistance to vancomycin was not widespread among our strains: only one Ec. faecium and one Ec. durans strain were found to be vancomycin resistant. Our results show a certain diversity in technological traits of the enterococcal strains isolated from artisanal Fiore Sardo, together with a low incidence of some potentially pathogenic traits of health concern.     

WWW in the Small

The web technology is increasingly used by communities of various kinds to support their memory and the interactions among their members. In these cases the WWW can be viewed as a web of local spaces (Web in the small), each characterized by local structure and semantics. The local space can be used to provide the community members with adaptive functionalities to enhance their navigations and to promote new forms of interaction among them. The realization and management of these functionalities are sustainable since they do not require more knowledge and effort than the ones the community generates and spends to survive. The paper presents a technology, the LAW system, which is a step towards a view of the Web in the small and complements more traditional technologies supporting the current acceptation of the World Wide Web (Web in the large). The LAW system is informed by an agent based model where space and its topology are first class concepts.