Diachronic (1979–2003) analysis of rice genetic diversity in Guinea did not reveal genetic erosion

Greater insight into the dynamics of genetic resources of crop plants is needed in order to pinpoint detrimental evolutionary patterns and draw up conservation priorities. Temporal evolution of rice genetic diversity was monitored in Maritime Guinea where subsistence-oriented agriculture prevails. Diachronic comparison was performed between samples collected in six villages during the 1979/1982-period and in 2003, based on the names and number of varieties inventoried and the polymorphism of microsatellite markers. The number of varieties appeared not to be comparable between the two dates, due to differences in the collection methods. The varietal composition had evolved very substantially between the two collection dates. Many long-duration varieties present in 1979/1982 had been abandoned and several improved varieties had been introduced. The mean number of alleles per locus and per accession was significantly higher in accessions collected in 2003. Pairwise comparisons of the mean number of alleles per locus in 1979/1982–2003 homonymous accession pairs indicated higher intra-accession diversity for the 2003 collections. Genetic differentiation, measured with the F _ST values, was very high and significant for more than 80% of these pairs of accessions. The overall genetic differentiation between accessions from the two collections dates was also significant. Significant changes were also observed for allelic composition. However, alleles specific of each collection date had much lower frequency, compared to alleles common to the two collection dates. These results suggest that rice genetic diversity in Maritime Guinea has been maintained or even enhanced. Old collections of crop genetic resources are often not exhaustive enough to undertake perfect diachronic comparison. New methods to utilize this historical data for diversity monitoring are needed.     

Stimulation of insulin and glucagon synthesis in rat Langerhans islets by malathion in vitro: Evidence for mitochondrial interaction and involvement of subcellular non-cholinergic mechanisms

We examined the effects of malathion, an organophosphorus (OP) insecticide, on glucagon, C-peptide, and insulin content or secretion from isolated rat Langerhans islets in vitro. Islets were isolated from the pancreas of rats by standard collagenase digestion, separation by centrifugation, and hand-picking technique. Then islets were cultured in medium and supplemented with various concentrations of malathion (25, 125, and 625 μg/ml) for 1, 3, and 5 h. In vitro exposure to malathion increased insulin and C-peptide contents at doses of 25, 125, and 625 μg/ml following 5 h incubation as compared to control. All doses of malathion increased glucagon content after 3 and 5 h as compared to control. Increase of the glucagon content at all doses in the fifth hour was higher than that of third hour. Malathion also decreased 2.8 and 16.7 mM glucose-stimulated insulin secretion at all doses after 30 min as compared to control.It is concluded that malathion reduce insulin exocytose in a short time (first hour) but after a long time (e.g., 5 h), the content of insulin is increased by compensating mechanisms such as resynthesize of insulin or aggregation of insulin. The present in vitro study for the first time proposes the involvement of subcellular non-cholinergic mechanisms in malathion-induced changes in Langerhans islets insulin and glucagon.     

Induction of insulin resistance by malathion: Evidence for disrupted islets cells metabolism and mitochondrial dysfunction

Hyperglycemia is observed with exposure to organophosphorus (OP) pesticides. The aim of this study was to investigate the effects of malathion on secretion of insulin from rat pancreatic islets in vitro and in vivo. Malathion was administered through food for 4 weeks at concentrations of 100, 200, and 400 ppm. For in vivo experiment, at the end of treatment, blood sample was obtained and plasma was separated. For in vitro experiment, the treated rats were anesthetized and underwent a laparatomy. The common bile duct was cannulated and the pancreas distended by injecting of cold collagenase V using peristaltic infusion pump. Islets were then hand picked under a stereomicroscope and cultured in the presence of various doses of glucose and KCl. Malathion at doses of 200 and 400 ppm increased plasma glucose and insulin concentrations and lowered activity of erythrocyte acetylcholinesterase. The isolated islets from pretreated animals with malathion 200 and 400 ppm showed lower glucose-stimulated insulin secretion while no change was observed in the presence of KCl. Light microscopic examination revealed that malathion causes patchy degenerative changes in pancreatic islets. Combination of in vivo and in vitro findings suggests that malathion induces a kind of insulin resistance that cannot overwhelm hyperglycemia. This action of malathion is mediated through disruption of islets mitochondrial function.     

In vitro clonal propagation of mature Tectona grandis through axillary bud proliferation

An in vitro clonal propagation procedure for mature Tectona grandis (teak) trees is described. Multiple shoots were induced from nodal segments through axillary bud proliferation. A shoot multiplication rate of 6.33 was achieved on Murashige and Skoog's (MS) medium supplemented with 10 μM 6-benzyladenine BA and 1 μM 1-naphthalene acetic acid (NAA) during every subculture cycle of 4 weeks. In vitro raised shoots could be successfully rooted (66.66%) on liquid MS medium supplemented with 15 μM NAA, with 1.60 roots per shoot, every 6 weeks of culture. In vitro hardening was carried out in sand soaked with half-strength MS medium (organic free). The plantlets were acclimatized first in a mist chamber and then in polybags in a mixture of soil, sand, and farmyard manure (1 : 1 : 1 v/v) in a shade house.     

Rice Root Genetic Architecture: Meta-analysis from a Drought QTL Database

During the last 10 years, a large number of quantitative trait loci (QTLs) controlling rice root morphological parameters have been detected in several mapping populations by teams interested in improving drought resistance in rice. Compiling these data could be extremely helpful in identifying candidate genes by positioning consensus QTLs with more precision through meta-QTL analysis. We extracted information from 24 published papers on QTLs controlling 29 root parameters including root number, maximum root length, root thickness, root/shoot ratio, and root penetration index. A web-accessible database of 675 root QTLs detected in 12 populations was constructed. This database includes also all QTLs for drought resistance traits in rice published between 1995 and 2007. The physical position on the pseudo-chromosomes of the markers flanking each QTL was determined. An overview of the number of root QTLs in 5-Mb segments covering the whole genome revealed the existence of “hot spots,” The 32 trait × chromosome combinations comprising six or more QTLs were subjected to a meta-QTL analysis using the software package MetaQTL. The method enabled us both to determine the likely number of true QTLs in these areas using an Akaike information criterion and to estimate their position. The meta-QTL confidence intervals were notably reduced and, for the smallest ones, encompassed only a few genes.     

Comparative study on immunomodulatory and growth enhancing effects of three prebiotics (galactooligosaccharide,fructooligosaccharide and inulin) in common carp (Cyprinus carpio)

This study investigated the effects of different prebiotics, including galactooligosaccharide (GOS), fructooligosaccharide (FOS) and inulin (INL), on skin mucosal immune parameters, humoral immune responses as well as performance of common carp (Cyprinus carpio). Two hundred and forty specimens (13.85 ± 0.85 g) were stocked in 12 fibreglass tanks assigned into three treatments and a control group. The experimental diets were formulated to have equal level (2%) of the prebiotics. At the end of the feeding trial, the highest skin mucus lysozyme activities and total immunoglobulin (total Ig) were observed in GOS‐fed group (P < 0.05). However, skin mucus protease activity showed no significant difference among different dietary groups (P < 0.05). Blood respiratory burst activity was significantly increased in all prebiotic‐fed fish compared to the control group (P < 0.05); the highest activity was observed in GOS treatment. Furthermore, evaluation of humoral immune response revealed that feeding with GOS‐supplemented diet significantly increased lysozyme and alternative complement (ACH50) activity as well as total Ig compared to the control and other prebiotic groups. While no significant difference was observed between FOS and INL groups, common carps fed GOS‐supplemented displayed improved (P < 0.05) growth performance, including final weight, weight gain, specific growth rate (SGR) and feed conversion ratio (FCR), compared to the control treatment. These results revealed that different prebiotics modulate carp growth and immune response in different manner, and GOS seems to be the most suitable prebiotic.     

The study of antioxidant enzymes and immune‐related genes expression in common carp (Cyprinus carpio) fingerlings fed different prebiotics

The aim of the present study was to study the effects of different prebiotics (galacto‐, fructooligosaccharide and inulin) on immune response and oxidative stress of common carp (Cyprinus carpio) fingerlings at the molecular level. A total number of 240 fish (13.85 ± 0.85 g) were supplied and randomly stocked in twelve fiberglass tanks (20 specimens per tank). Fish were fed a basal formulated diet (Control) or basal diet supplemented with equal level (2%) of different prebiotics (four treatments repeated in triplicated) for 8 weeks. At the end of feeding trial, the expression of immune‐related genes (interleukin 1 beta [IL‐1β], IL‐8, IL‐10, lysozyme [LYZ], tumour necrosis factor alpha [TNF‐α] and transforming growth factor beta [TGF‐β]) were determined in head kidney and intestine tissues and the expression of antioxidant‐related genes (glutathione S‐transferase [GST‐α], glutathione reductase [GR] and glutathione peroxidase genes [GPX]) were studied in intestine. The results revealed that dietary administration of prebiotics modulated the expression of immune‐related genes and the degree of expression was affected by the type of prebiotics and the organ that was used for analyses. Also, evaluation of antioxidant genes expression showed that GSTα and GR expression levels increased as a result of feeding common carp with the prebiotics. According to these findings, it can be concluded that feeding on different prebiotics had altered effects on the expression of immune and antioxidant‐related genes.     

Species and space: a combined gap analysis to guide management planning of conservation areas

Landscape Ecology - With accelerating global declines in biodiversity, establishment and expansion of conservation areas (CAs) have increasingly been advocated in recent decades. Gap analysis has...     

Planning and management modeling for treated wastewater usage

Due to urban growth, some agricultural lands have been replaced by residential, municipal, and industrial areas. In some cases the remaining agricultural land will not have enough water because of transfers from agriculture to M&I (municipal and industrial) users. Therefore, in many places, especially in arid and semi-arid regions, the use of treated wastewater as a reliable source of irrigation water has already been, or will be, considered in the future. Due to its unique characteristics, this new resource has many challenges that cannot be ignored, such as health issues, water quality, and long- and short-term effects on soils and crops. The study described herein considered the development of a new GIS-based model for planning and managing the reuse of treated wastewater for the irrigation of agricultural and green lands, considering various factors such as population and urban growth. The model is composed of several different modules, including an urban growth model. These modules are designed to help in the decision-making process for allocations of water resources to agricultural areas, considering factors such as crop types, crop pattern, water salinity, soil characteristics, pumping and conveyance costs, and also by comparing different management scenarios. Appropriate crops that can be grown with a specific water salinity and soil characteristics, proper water resources for each farm (according to pumping and conveyance costs, and analysis of water demand, and water supply) can be determined through the application of this model. The model can also rank agricultural areas and open spaces in and near an urban area according to their suitability for irrigated agriculture.     

Overwintering biology of the carob moth Apomyelois ceratoniae (Lepidoptera: Pyralidae)

The pomegranate fruit moth, Apomyelois ceratoniae (Zeller), is the most important pest of pomegranate orchards in Iran, where infestations lead to 20%–80% fruit loss. A. ceratoniae overwinters as larvae in several instars. The success in overwintering determines the fruit loss in the following season, thus overwintering physiology of A. ceratoniae could provide insights into population prediction. To this end, overwintering strategy and some seasonal physiological and biochemical changes were investigated in the field-collected larvae of A. ceratoniae. The lowest supercooling point was recorded in November (?14.6 ± 0.9 °C) and the highest in both October and March (?10.2 ± 0.9 °C). The median lethal temperature (LT₅₀) of larvae was higher than supercooling point, suggesting that A. ceratoniae is chill-susceptible. Overwintering larvae had slightly higher concentrations of glycerol and sorbitol compared to summer larvae. There were no significant seasonal changes in body water content or hemolymph osmolality. Current winter temperatures in Iranian orchards are higher than the cold tolerance thresholds of A. ceratoniae, suggesting that overwintering mortality is not a key factor in determining A. ceratoniae populations.