Destruction of Trypanosoma cruzi by Natural killer cells

Mice infected with trypanosoma cruzi or stimulated with poly(inosinic.cytodylic acid) were found to possess splenic and peritoneal exudate cells with enhanced cytotoxic activity against epimastigote and trypomastigote forms of Trypanosoma cruzi. By use of specific alloantiserums it was determined that the effector cells responsible for this cytotoxic activity were typical natural killer cells.     

Institution, Legislation and Policy Analysis of China’s Wetland Protection

Wetland protection is a complex issue. In the executive system of wetland preservation, the central government is the main body of policy formulation and implementation. Although China has taken many steps to protect wetlands, there are still some institutional, legal and policy problems in the area of wetland protection. This article presents an analysis of these factors. First, the authors state and analyze the major legal and management problems currently hampering wetland protection in China. Then the authors believe that in the future, new problems of wetland protection will arise. Given the following three major aspects of wetland protection in China: i.e., the policy, law and management systems, this article provides some relevant suggestions in the area of policies and management.     

Development of a biocatalytic process for the production of c6-aldehydes from vegetable oils by soybean lipoxygenase and recombinant hydroperoxide lyase

Volatile C6- and C9-aldehydes and alcohols are widely used as food flavors to reconstitute the "fresh green" odor of fruits and vegetables lost during processing. To meet the high demand for natural flavors, an efficient, cheap, and versatile biocatalytic process was developed to produce C6-aldehydes on a large scale. Vegetable oils were converted by soybean lipoxygenase and recombinant hydroperoxide lyase into hexanal and (2E)- or (3Z)-hexenal. In contrast to plant extracts, generally used as enzyme sources, high molar conversions were obtained with recombinant hydroperoxide lyase (50% for hexanal and 26% for hexenal formation), and no side products were formed. Furthermore, recombinant hydroperoxide lyase lacks isomerase activity, allowing production of (3Z)-hexenal, which could not be obtained in previously described processes. Recombinant hydroperoxide lyase is stable and can be stored at 4 degrees C for 1 month without significant loss of activity.     

Measuring onion cultivars with image analysis using inflection points

Summary The suitability of image analysis was studied to measure bulb characteristics for varietal testing of onions (Allium cepa L.). Eighteen genotypes were used, which covered a whole range of onion shapes, including some quite identical ones. The characteristic height and diameter were measured both by image analysis and by hand. The methods gave comparable results with regard to precision and discriminating power. The discriminating power of the image analysis method could be increased by adding a new characteristic: the relative position of the diameter.For determining the height of the bulb with image analysis two methods are described to locate the top of a bulb. One method is to use the location of the inflection point as the top of the bulb. For most bulb shapes, this point coincides with the top of the bulb as indicated by a crop expert. For ovate shaped onions, however, the inflection point is below the top of the bulb as indicated by the crop expert. The other method is to use the location of the intercept of the tangent at the inflection point with the length axis of the bulb as the top of the bulb. This point is always above the top as indicated by the crop expert. Moreover it seems to perform slightly worse for the discrimination of cultivars. Therefore the location of the inflection point as the top of the bulb is preferred.     

A laboratory test protocol to evaluate effects of plant protection products on mortality and reproduction of the predatory mite<Emphasis Type="Italic">hypoaspis aculeifer</Emphasis> canestrini (acari: laelapidae) in standard soil

We provide a test protocol to evaluate the effects of plant protection products on mortality and reproductive performance ofHypoaspis aculeifer (Acari: Laelapidae). The test design is in compliance with standard characteristics of extended laboratory studies as formulated by international expert panels dealing with non-target arthropod testing schemes. Potential effects on survival rates are evaluated by assessing mortality after an exposure period of 14 days that starts with protonymphs. The reproductive performance of surviving mites is studied by following the egg production of individually isolated females over a 7-day period. The hatching success of these eggs is assessed subsequently. Using several years’ data obtained from water control treatments, we propose criteria to evaluate the validity of individual experiments.     

Analysis of clonal germplasm from five Saccharum species: S. barberi , S. robustum, S. officinarum, S. sinense and S. spontaneum . A study of inter- and intra species relationships using microsatellite markers

In order to study relationships within and among species of the highly complex polyploid genus Saccharum, 30 clones from 5 species (S. barberi, S. officinarum, S. robustum, S. sinense, and S. spontaneum) and 6 cultivated clones were analyzed using 15 sugarcane simple sequence repeat (SSR) markers and two multivariate statistical methods. The origins of two species, S. barberi and S. sinense, are unclear, and it has been hypothesized that they arose from crosses of S. officinarum × S. spontaneum. S. robustum is suggested to be ancestral to S. officinarum, which, when crossed with S. spontaneum, principally comprise the genomes of commercial cultivars. Although our analyses supported S. robustum as being an ancestor of S. officinarum, and show the composition of commercial clones as expected, our results concerning the species S. barberi and S. sinense indicated them to be much less related to the main Saccharum germplasm pool than previous molecular marker investigations, suggesting that introgression from other genera may exist in their ancestry. The differing results of our analysis of S. barberi and S. sinense are likely attributable to more equal and larger numbers of clones studied in each species. Given the extremely high ploidy, the use of only 15 SSR markers enabled clear distinction of Saccharum species and clones, and also identified likely mislabeled accessions. In addition, the replication of DNA extraction, polymerase chain reactions, and fragment electrophoresis increased the robustness of our analysis.     

Incorporation of chlorogenic acids in coffee brew melanoidins

The incorporation of chlorogenic acids (CGAs) and their subunits quinic and caffeic acids (QA and CA) in coffee brew melanoidins was studied. Fractions with different molecular weights, ionic charges, and ethanol solubilities were isolated from coffee brew. Fractions were saponified, and the released QA and CA were quantified. For all melanoidin fractions, it was found that more QA than CA was released. QA levels correlated with melanoidin levels, indicating that QA is incorporated in melanoidins. The QA level was correlated with increasing ionic charge of the melanoidin populations, suggesting that QA may contribute to the negative charge and consequently is, most likely, not linked via its carboxyl group. The QA level correlated with the phenolic acid group level, as determined by Folin-Ciocalteu, indicating that QA was incorporated to a similar extent as the polyphenolic moiety from CGA. The QA and CA released from brew fractions by enzymes confirmed the incorporation of intact CGAs. Intact CGAs are proposed to be incorporated in melanoidins upon roasting via CA through mainly nonester linkages. This complex can be written as Mel=CA-QA, in which Mel represents the melanoidin backbone, =CA represents CA nonester-linked to the melanoidin backbone, and -QA represents QA ester-linked to CA. Additionally, a total of 12% of QA was identified in coffee brew, whereas only 6% was reported in the literature so far. The relevance of the additional QA on coffee brew stability is discussed.     

The potential of high-resolution BAC-FISH in banana breeding

The genetic complexity in the genus Musa has been subject of study in many breeding programs worldwide. Parthenocarpy, female sterility, polyploidy in different cultivars and limited amount of genetic and genomic information make the production of new banana cultivars difficult and time consuming. In addition, it is known that part of the cultivars and related wild species in the genus contain numerous chromosomal rearrangements. In order to produce new cultivars more effectively breeders must better understand the genetic differences of the potential crossing parents for introgression hybridization, but extensive genetic information is lacking. As an alternative to achieve information on genetic collinearity we make use of modern chromosome map technology known as high-resolution fluorescent in situ hybridization (FISH). This article presents the technical aspects and applications of such a technology in Musa species. The technique deals with BAC clone positioning on pachytene chromosomes of Calcutta 4 (Musa acuminata ssp. burmanicoides, A genome group, section Eumusa) and M. velutina (section Rodochlamys). Pollen mother cells digestion with pectolytic enzymes and maceration with acetic acid were optimized for making cell spread preparations appropriate for FISH. As an example of this approach we chose BAC clones that contain markers to known resistance genes and hybridize them for establishing their relative positions on the two species. Technical challenges for adapting existing protocols to the banana cells are presented. We also discuss how this technique can be instrumental for validating collinearity between potential crossing parents and how the method can be helpful in future mapping initiatives, and how this method allows identification of chromosomal rearrangements between related Musa species and cultivars.     

Structures of the CXCR4 chemokine GPCR with small-molecule and cyclic peptide antagonists

Chemokine receptors are critical regulators of cell migration in the context of immune surveillance, inflammation, and development. The G protein-coupled chemokine receptor CXCR4 is specifically implicated in cancer metastasis and HIV-1 infection. Here we report five independent crystal structures of CXCR4 bound to an antagonist small molecule IT1t and a cyclic peptide CVX15 at 2.5 to 3.2 angstrom resolution. All structures reveal a consistent homodimer with an interface including helices V and VI that may be involved in regulating signaling. The location and shape of the ligand-binding sites differ from other G protein-coupled receptors and are closer to the extracellular surface. These structures provide new clues about the interactions between CXCR4 and its natural ligand CXCL12, and with the HIV-1 glycoprotein gp120.     

Assessing crop management options with crop simulation models based on generated weather data

The efficient use of crop simulation models is an effective complement to experimental research. Long-term weather data obtained at a specific site are normally required for the application of these crop simulation models to help determine alternate management practices and associated decisions. Stochastic weather generators sometimes are used to complement or substitute historical weather data. The objective of this study was to evaluate the suitability of weather data generated by the weather generators WGEN and SIMMETEO as input for crop simulation models in order to determine the best option(s) among a number of different crop management practices. Five locations across Iran representing different climates were selected. The wheat, maize, and soybean models of the Decision Support System for Agrotechnology Transfer (DSSAT) were applied in this study, using 30 years of observed weather data and 90 years of weather data generated by WGEN and SIMMETEO. Simulated grain yield using either observed weather data or weather data generated by WGEN and SIMMETEO in response to various ‘experimental’ factors, e.g., cultivar selection, planting date, planting density, irrigation threshold, and change in precipitation under irrigated and rainfed conditions were compared. The statistical evaluation was based on t, F, and Kolomogrov-Smirnov (K-S) tests. The average of the percentage rejected tests was 20% and the parameter estimation method had no impact on the number of rejected tests. Irrespective of some significant differences between simulated yield based on observed weather data and those based on weather data generated by WGEN and SIMMETEO, a similar conclusion could be drawn about the best cultivar, planting date, plant density and irrigation threshold and response to changes in the amount of precipitation. Based on the results of this study it can be concluded that for many crop model applications where only relative estimates or determination of the best management option(s) rather than absolute values are required, weather data generated by either WGEN and SIMMETEO are accurate and sufficient.