Relationship between environmental variables and surface activity of scorpions in the Arid Chaco ecoregion of Argentina

Many environmental factors may influence the activity of scorpions in arid ecosystems. In this study, we examined the effects of such factors on scorpion activity at a mature and a secondary forest site in the Chancaní Reserve (Arid Chaco ecoregion in Córdoba, Argentina). Scorpions were collected using pitfall traps, and their nocturnal activity was observed by means of UV light during 14 nights. Temperature, air humidity, atmospheric pressure, and wind velocity were measured, and the percentage of visible moon was estimated. A total of 440 scorpions, representing seven species belonging to two families (Bothriuridae and Buthidae), were observed in the study area. Brachistosternus ferrugineus was the species most commonly observed using both methods. Mature and secondary forest shared slightly more than 50% of species. Surface activity of scorpions observed with the two methods differed significantly between the two areas. Surface activity of all scorpions and of B. ferrugineus were negatively related to the phase of the moon and positively related to air temperature. Physical factors thus have important effects on scorpion activity.     

Use of a Base-Labile Protected Derivative of 6-Mercaptohexanol for the Preparation of Oligonucleotides Containing a Thiol Group at the 5′-End

Abstract

The preparation of a base-labile (Dnpe) protected derivative of 6-mercaptohexanol is described. The use of the phosphoramidite derivative of this compound improves both yields and the time needed for the preparation of oligonucleotides containing a thiol group at the 5′-end.     

Efficacy of soil treatments of entomopathogenic nematodes against the larvae, pupae and adults of Tuta absoluta and their interaction with the insecticides used against this insect

The efficacy of soil treatments of three native entomopathogenic nematodes (Steinernema carpocapsae, S. feltiae and Heterorhabditis bacteriophora) against Tuta absoluta larvae, pupae and adults was determined under laboratory conditions. The effect of three insecticides commonly used against T. absoluta, in the survival, infectivity and reproduction of these nematode strains was also evaluated. When dropped into soil to pupate, soil application of nematodes resulted in a high mortality of larvae: 100, 52.3 and 96.7 % efficacy for S. carpocapsae, S. feltiae and H. bacteriophora respectively. No mortality of pupae was observed and mortality of adults emerging from soil was 79.1 % for S. carpocapsae and 0.5 % for S. feltiae. The insecticides tested had a negligible effect on nematode survival, infectivity and reproduction. No sublethal effects were observed. Infective juveniles that survived to insecticide exposition were able to infect Galleria larvae with no significant differences from the control. The Galleria larvae affected by the three insecticides tested served as suitable hosts for the infection and reproduction of the nematodes. These results suggest that larvae of T. absoluta, falling from leaves following insecticide application, could be suitable hosts for nematodes, thereby increasing their concentration and persistence in the soil.     

Modulation of the Endocannabinoids N-Arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) on Executive Functions in Humans

Animal studies point to an implication of the endocannabinoid system on executive functions. In humans, several studies have suggested an association between acute or chronic use of exogenous cannabinoids (Δ9-tetrahydrocannabinol) and executive impairments. However, to date, no published reports establish the relationship between endocannabinoids, as biomarkers of the cannabinoid neurotransmission system, and executive functioning in humans. The aim of the present study was to explore the association between circulating levels of plasma endocannabinoids N-arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) and executive functions (decision making, response inhibition and cognitive flexibility) in healthy subjects. One hundred and fifty seven subjects were included and assessed with the Wisconsin Card Sorting Test; Stroop Color and Word Test; and Iowa Gambling Task. All participants were female, aged between 18 and 60 years and spoke Spanish as their first language. Results showed a negative correlation between 2-AG and cognitive flexibility performance (r = −.37; p<.05). A positive correlation was found between AEA concentrations and both cognitive flexibility (r = .59; p<.05) and decision making performance (r = .23; P<.05). There was no significant correlation between either 2-AG (r = −.17) or AEA (r = −.08) concentrations and inhibition response. These results show, in humans, a relevant modulation of the endocannabinoid system on prefrontal-dependent cognitive functioning. The present study might have significant implications for the underlying executive alterations described in some psychiatric disorders currently associated with endocannabinoids deregulation (namely drug abuse/dependence, depression, obesity and eating disorders). Understanding the neurobiology of their dysexecutive profile might certainly contribute to the development of new treatments and pharmacological approaches.     

A Hybrid Likelihood Model for Sequence-Based Disease Association Studies

In the past few years, case-control studies of common diseases have shifted their focus from single genes to whole exomes. New sequencing technologies now routinely detect hundreds of thousands of sequence variants in a single study, many of which are rare or even novel. The limitation of classical single-marker association analysis for rare variants has been a challenge in such studies. A new generation of statistical methods for case-control association studies has been developed to meet this challenge. A common approach to association analysis of rare variants is the burden-style collapsing methods to combine rare variant data within individuals across or within genes. Here, we propose a new hybrid likelihood model that combines a burden test with a test of the position distribution of variants. In extensive simulations and on empirical data from the Dallas Heart Study, the new model demonstrates consistently good power, in particular when applied to a gene set (e.g., multiple candidate genes with shared biological function or pathway), when rare variants cluster in key functional regions of a gene, and when protective variants are present. When applied to data from an ongoing sequencing study of bipolar disorder (191 cases, 107 controls), the model identifies seven gene sets with nominal p-values0.05, of which one MAPK signaling pathway (KEGG) reaches trend-level significance after correcting for multiple testing.