Dicer-2-Dependent Generation of Viral DNA from Defective Genomes of RNA Viruses Modulates Antiviral Immunity in Insects

1. Download high-res image (228KB)
2. Download full-size image

     

CO<Subscript>2</Subscript> enrichment affects eco-physiological growth of maize and alfalfa under different water stress regimes in the UAE

Water stress has been reported to alter morphology and physiology of plants affecting chlorophyll content, stomatal size and density. In this study, drought stress mitigating effects of CO₂ enrichment was assessed in greenhouse conditions in the hot climate of UAE. Commercially purchased maize (Zea mays L.) and alfalfa (Medicago sativa L.) were seeded in three different custom-built cage structures, inside a greenhouse. One cage was kept at 1000 ppm CO₂, the second at 700 ppm CO₂, and the third at ambient greenhouse CO₂ environment (i.e. 435 ppm). Three water stress treatments HWS (200 ml per week), MWS (400 ml per week), and CWS (600 ml per week) were given to each cage so that five maize pots and five alfalfa pots in each cage received same water stress treatments. In maize, total chlorophyll content was similar or higher in water stress treatments compared to control for all CO₂ concentrations. Stomatal lengths were higher in enriched CO₂ environments under water stress. At 700 ppm CO₂, stomatal widths decreased as water stress increased from MWS to HWS. At both enriched CO₂ environments, stomatal densities decreased compared to ambient CO₂ environment. In alfalfa, there was no significant increase in total chlorophyll content under enriched CO₂ environments, even though a slight increase was noticed.     

The genetic architecture of photosynthesis and plant growth‐related traits in tomato

To identify genomic regions involved in the regulation of fundamental physiological processes such as photosynthesis and respiration, a population of Solanum pennellii introgression lines was analyzed. We determined phenotypes for physiological, metabolic, and growth related traits, including gas exchange and chlorophyll fluorescence parameters. Data analysis allowed the identification of 208 physiological and metabolic quantitative trait loci with 33 of these being associated to smaller intervals of the genomic regions, termed BINs. Eight BINs were identified that were associated with higher assimilation rates than the recurrent parent M82. Two and 10 genomic regions were related to shoot and root dry matter accumulation, respectively. Nine genomic regions were associated with starch levels, whereas 12 BINs were associated with the levels of other metabolites. Additionally, a comprehensive and detailed annotation of the genomic regions spanning these quantitative trait loci allowed us to identify 87 candidate genes that putatively control the investigated traits. We confirmed 8 of these at the level of variance in gene expression. Taken together, our results allowed the identification of candidate genes that most likely regulate photosynthesis, primary metabolism, and plant growth and as such provide new avenues for crop improvement.     

Assessment of the Bioaccessibility of Trace Elements in Cat’s Claw Teas by In Vitro Simulated Gastrointestinal Digestion Using FAAS

Beer is a widely consumed drink throughout the world, and because its manufacture involves the use of water, beer can be, in some cases, a source of fluorides. For this reason, the objective of this study was to determine the concentration of fluorides in 50 samples of beers from different sources sold in two different types of container (aluminum can and glass bottle). The possible significant differences between the different types of packaging and the intake of fluoride from the consumption of these beers were evaluated. The concentration of fluoride in beers has been determined using the potentiometric method of fluoride determination by standard addition. The concentration of fluoride ranged between 0.06 and 1.77 mg/L. In general, the concentration was below 1 mg/L, except for three beer samples from Ireland and the USA, whose concentration was over 1.5 mg/L. No significant differences were found between the types of packaging. The contribution of fluoride to the diet from beer consumption is not high (<27%); however, it is necessary to warn consumers whenever they are in areas of high concentrations of fluoride in the water supply.     

Identification and characterization ofMycobacterium paratuberculosis recombinant proteins expressed inE. coli

Mycobacterium paratuberculosis is the causative agent of Johne's disease, a chronic enteritis in ruminants, and it has also been isolated and identified from patients with Crohn's disease, an inflammatory bowel disease. The control of Johne's disease has been hampered by the lack of a reliable diagnostic test because of the large degree of antigenic cross-reactivity between mycobacterial and non-mycobacterial species. To help identify specific antigen(s) or epitope(s), anM. paratuberculosis expression library was screened with antibodies and DNA probes. In total, 54 clones were randomly picked, purified, and characterized by DNA probes and monoclonal antibodies with known specificity to individual mycobacterial antigens. Four clones carrying the heat shock protein 65K-, two representing the secreted protein 32K-, three representing the 21K-, and 20 clones representing the specific insertion element ofM. paratuberculosis (IS900)-encoding genes and their gene products were identified and characterized. Well-defined recombinant antigens and/or epitopes representingM. paratuberculosis may facilitate the development of specific diagnostic tests and the investigation of their role in these chronic diseases.     

Vitamin A in the Vision of Insects

Acetone-methanol extracts of honeybees (Apis mellifera) were chromatographed from petroleum ether on columns of aluminum oxide and magnesium oxide:celite. Vitamin A₁ was identified by the Carr-Price (antimony chloride) reaction. These experiments provide the first demonstration of vitamin A in the tissues of an insect. Like retinene, vitamin A is confined to the heads and is not found in either thoraces or abdomens. Dark-adapted bees have very little vitamin A. During light adaptation the vitamin A increases, but at the expense of retinene, which decreases. As much as 0.1 µg of vitamin A/gm of heads has been recovered from light-adapted bees. Two methods are described for demonstrating the enzymic reduction of retinene to vitamin A, using an extract of the heads of honeybees.     

Heritability of determinants of the metabolic syndrome among healthy Arabs of the Oman family study

The metabolic syndrome, as defined by the International Diabetes Federation, was investigated in five large, extended, highly consanguineous, healthy Omani Arab families of a total of 1277 individuals. Heritability (h2) of the phenotypic abnormalities that make up the syndrome and other related traits was estimated by variance decomposition method using SOLAR software. The overall prevalence of the syndrome was 23%. The prevalence of abnormalities making the syndrome in a descending order were: obligatory waist circumference, hypertension, raised fasting blood glucose, low serum high-density lipoprotein (HDL), and raised serum triglycerides (TGs). Highly significant, but widely spread, h2 values were obtained for: height (0.68), weight (0.68), BMI (0.68), serum HDL (0.63), serum leptin (0.55), percentage body fat (0.53), total serum cholesterol (0.53), fasting serum insulin (0.51), homeostasis model assessment-insulin resistance index (0.48), serum TG (0.43), waist circumference (0.40), diastolic blood pressure (0.38), and 2-hour glucose level (0.17), whereas for the metabolic syndrome itself, h2 was 0.38. The wide spread of h2 results (0.07 to 0.68) indicates that some determinants, such as weight, BMI, and HDL level, are under significant genetic influence among the Omani Arabs. Other determinants such as insulin resistance, abdominal obesity, diastolic blood pressure, and TG levels seem to be more environmentally driven.     

A Solanum neorickii introgression population providing a powerful complement to the extensively characterized Solanum pennellii population

We present a complementary resource for trait fine‐mapping in tomato to those based on the intra‐specific cross between cultivated tomato and the wild tomato species Solanum pennellii, which have been extensively used for quantitative genetics in tomato over the last 20 years. The current population of backcross inbred lines (BILs) is composed of 107 lines derived after three backcrosses of progeny of the wild species Solanum neorickii (LA2133) and cultivated tomato (cultivar TA209) and is freely available to the scientific community. These S. neorickii BILs were genotyped using the 10K SolCAP single nucleotide polymorphism chip, and 3111 polymorphic markers were used to map recombination break points relative to the physical map of Solanum lycopersicum. The BILs harbor on average 4.3 introgressions per line, with a mean introgression length of 34.7 Mbp, allowing partitioning of the genome into 340 bins and thereby facilitating rapid trait mapping. We demonstrate the power of using this resource in comparison with archival data from the S. pennellii resources by carrying out metabolic quantitative trait locus analysis following gas chromatography–mass spectrometry on fruits harvested from the S. neorickii BILs. The metabolic candidate genes phenylalanine ammonia‐lyase and cystathionine gamma‐lyase were then tested and validated in F₂ populations and via agroinfiltration‐based overexpression in order to exemplify the fidelity of this method in identifying the genes that drive tomato metabolic phenotypes.