Evaluation of hepatitis E virus infection between different production systems of pigs in Brazil

The objectives of this study were to (1) investigate the occurrence of hepatitis E virus (HEV) in pigs from large-scale and family-scale farms, (2) genetically characterize the strains isolated, and (3) study the pathogenesis of swine HEV infection via immunohistochemistry. A total of 50 pigs from 10 farms in Mato Grosso State, Brazil were divided according to type of production system into either large-scale farms (n?=?5) or family-scale farms (n?=?5). Samples of liver, gallbladder, small and large intestines, bile, and feces from the pigs were analyzed by nested PCR with primers targeting the ORF2 region of HEV and by immunohistochemistry. Of the eight HEV-positive samples from pigs of family-scale farms, phylogenetic analysis revealed that seven of the swine HEV isolates clustered with subtype 3b of genotype 3 and one isolate was categorized with subtype 3 f. The HEV antigen was detected mainly in the small intestine samples from family-scale farms, suggesting an early stage HEV infection. HEV was not detected in the samples of pigs from large-scale farms, reinforcing the need for additional studies to evaluate the risk of transmission of HEV to humans from pigs from family-scale farms in Mato Grosso State.     

Morphological changes and self-incompatibility breakdown associated with autopolyploidization in <Emphasis Type="Italic">Hylocereus</Emphasis> species (Cactaceae)

Chromosome duplication—autopolyploidization—may affect plant morphology and breeding systems, ultimately enabling the production of improved genotypes. In this study, the autotetraploid lines obtained from the self-incompatible diploid Hylocereus monacanthus and the autooctapolyploid lines obtained from the self-compatible tetraploid H. megalanthus were studied and compared with the donor accessions. The resulting H. monacanthus autotetraploids exhibit lower fruit weight, seed number, and pollen viability than the donor plant, but it has larger pollen grains. Although the resulting H. megalanthus autooctaploids had larger pollen grains and lower pollen viability compared with the donor plant, only aborted fruits were obtained from these lines. The most valuable change observed was the breakdown of the self-incompatibility system in the H. monacanthus autotetraploid lines. This research provides important information on the horticultural value of vine cacti autopolyploid lines.     

Genomic analysis in three Hylocereus species and their progeny: evidence for introgressive hybridization and gene flow

Interest in vine cacti of the genus Hylocereus (Cactaceae) has grown markedly due to their high economic potential as exotic fruit crops. Thus, we investigate the genomic and genetic characteristics of 18 accessions belonging to three Hylocereus species, from which were produced eight progeny from self-pollination and 51 interspecific-homoploid and -interploid hybrids. We reported ploidy estimation, allele frequencies, polymorphic information content (PIC) and genetic relationships observed among the Hylocereus species and their progeny. The progeny were diploid, triploid, tetraploid, pentaploid, or hexaploid. Each primer combination used in this work amplified different sets of restriction fragments ranging from 74 to 102 bands. Among the total number of bands observed for the Hylocereus accessions and their progeny, 97.5 and 98.1 %, respectively, were polymorphic. The variability of PIC between primers, species and hybrids suggested high heterozygosity and gene flow between them. In addition, amplified fragment length polymorphism (AFLP) markers were used to successfully identify one of the H. megalanthus accessions beforehand as the unknown male progenitor of the allotriploid S-75. AFLP markers demonstrate the efficacy for assessing genetic relationships and introgression; and provide strong support for the pursuit of additional breeding programs of these fruit crop.     

Embryo rescue and plant regeneration following interspecific crosses in the genus <Emphasis Type="Italic">Hylocereus</Emphasis> (Cactaceae)

The aim of this study was to develop an efficient methodology to rescue embryos following interspecific crosses in the genus Hylocereus. Crosses between the diploids Hylocereus polyrhizus and H. undatus in both directions were performed. Fertilized ovules carrying embryos at very early pro-embryonic stages were excised from ovaries 5 days after pollination (DAP) and placed on half-strength basal MS medium containing 680 μM glutamine, 0.55 μM α-naphthaleneacetic acid (NAA), 0.45 μM thidiazuron (TDZ) and various concentrations of sucrose. After 30 days in culture, ovules were isolated from the surrounding tissue and transferred to the same fresh medium. Significant differences were found between the main effects (cross and sucrose concentration) in ovule response, i.e., increased ovule size and callus formation. The best responses were obtained in the cross: H. polyrhizus × H. undatus; and sucrose concentration of 0.09 M. In terms of embryo conversion, polyembryony and number of regenerated plants, the highest responses were observed on the culture medium supplemented with 0.17 M sucrose in both interspecific crosses. All tested plants were found to be diploid by flow cytometric analyses. Fluorescent amplified—fragment length polymorphism (fAFLP) confirmed the hybrid origin of the regenerated plants. This study reports on the success of a three-step embryo rescue procedure for Hylocereus species. The procedure developed here provides the means for producing plants from very-early embryo stage, thus expanding the prospects for vine-cactus breeding programs.     

Leaf anatomical characteristics and physiological responses to short-term drought in Ziziphusmauritiana (Lamk.)

The aim of this work was to study the association between leaf anatomical characteristics and response to short-term drought stress in Ziziphusmauritiana Lamk. Six Z. mauritiana cultivars (Seb, Gola, Umran, Keitly, Q-29 and B-5/4) under field conditions in Israel's Negev desert were studied. Width of palisade mesophyll, spongy mesophyll and epidermis, xylem number and diameter in mid-vein were investigated with light microscopy. Short-term (3 weeks) drought stress tolerance was evaluated by monitoring plant response (leaf transpiration, diffusive resistance, chlorophyll fluorescence, leaf water potential and leaf relative water content). Greater epidermis and mesophyll widths and xylem diameters and densities were associated with increased tolerance to short-term water deficit expressed by preliminary wilting symptoms and proportional differences between initial and final physiological parameters. Significantly larger differences were found in Keitly, Umran and B-5/4 than in Seb, Gola and Q-29, indicating that the former cultivars are more sensitive to drought stress. Our results indicate that tolerance in descending order was Seb, Q-29, Gola, B-5/4, Keitly and finally Umran. The existence of an association between anatomical characteristics and short-term drought stress tolerance based on physiological responses is suggested.     

Grape Seed-Derived Procyanidins Decrease Dipeptidyl-peptidase 4 Activity and Expression

Dipeptidyl-peptidase 4 (DPP4) inhibitors are among the newest treatments against type 2 diabetes. Since some flavonoids modulate DPP4 activity, we evaluated whether grape seed-derived procyanidins (GSPEs), which are antihyperglycemic, modulate DPP4 activity and/or expression. In vitro inhibition assays showed that GSPEs inhibit pure DPP4. Chronic GSPE treatments in intestinal human cells (Caco-2) showed a decrease of DPP4 activity and gene expression. GSPE was also assayed in vivo. Intestinal but not plasmatic DPP4 activity and gene expression were decreased by GSPE in healthy and diet-induced obese animals. Healthy rats also showed glycemia improvement after oral glucose consumption but not after an intraperitoneal glucose challenge. In genetically obese rats, only DPP4 gene expression was down-regulated. Thus, procyanidin inhibition of intestinal DPP4 activity, either directly and/or via gene expression down-regulation, could be responsible for some of their effects in glucose homeostasis.     

Effect of some granular insecticides currently used for the treatment of maize crops (Zea mays) on the survival of inoculated Azospirillum lipoferum

Four insecticides, carbofuran, chlormephos, terbufos and benfuracarb, currently used on maize (Zea mays) at sowing, were tested for their compatibility with Azospirillum lipoferum strain CRT₁ used as an inoculant to improve maize growth and yield. The growth or survival of A lipoferum was studied in the presence of the insecticides: (1) in liquid and solid cultures of the bacteria, (2) when a commercial inoculant (Azogreen‐m?, Liphatech, Meyzieu, France) was inoculated directly on insecticide granules, (3) when inoculated Azogreen‐m granules were mixed with insecticide granules and (4) when inoculated Azogreen‐m granules were delivered separately to the seed bed. Of the four insecticides tested, only terbufos had a slight effect on growth of A lipoferum in solid cultures. All the insecticides decreased the survival of A lipoferum when the bacteria were inoculated directly on to the granules, or when inoculated Azogreen‐m granules were mixed with an insecticide. We hypothesize that the discrepancies between bacterial culture tests and survival studies might be explained by the conditions of desiccation encountered during inoculation of the granules. Desiccation stress could increase the toxic effect of the insecticides. We therefore suggest including desiccation stress in the biotest used to assess inoculant‐pesticide compatibility. © 2001 Society of Chemical Industry