Characterization of extracellular vesicle miRNA identified in peripheral blood of chronic pancreatitis patients

Molecular and Cellular Biochemistry - Plasma-derived extracellular vesicles (EV) can serve as markers of cell damage/disease but can also have therapeutic utility depending on the nature of their...     

Effect of pH on the phase behavior of DMPC bilayers

We have studied the effect of acidic pH on the phase behavior of the zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) using differential scanning calorimetry and x-ray scattering. Dispersions of DMPC in HCl solutions of pH = 4 and 3 behave identical to dispersions in water. The main transition temperature increases sharply and the pre-transition disappears at lower pH. An untilted gel phase is observed at pH = 2 and 1, in contrast to the tilted gel phase found at higher pH. The relatively large periodicity of the untilted gel phase, in comparison to that of the tilted gel phase occurring near neutral pH, clearly demonstrates the simultaneous charging and dehydration of the headgroups as the pH approaches the pK of the phosphate group. Headgroup dehydration at low pH also leads to the formation of DMPC crystallites and the inverted hexagonal phase at low and high temperatures, respectively, after a few days of incubation. These results show the significant effect of acidic pH on the phase behavior of zwitterionic lipids.     

The poor health of deep-water species in the context of fishing activity and a warming climate: will populations of Molva species rebuild or collapse?

Many deep-water fish populations, being K-selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (Molva dypterygia) and Mediterranean or Spanish ling (Molva macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, to shed light on the challenges these deep-water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which are analysed here have been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepato-somatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the northeastern Atlantic and the Mediterranean suggest that only some populations located in the North Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, this study's results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions.     

Afrotropical sand fly-host plant relationships in a leishmaniasis endemic area,Kenya

The bioecology of phlebotomine sand flies is intimately linked to the utilization of environmental resources including plant feeding. However, plant feeding behavior of sand flies remains largely understudied for Afrotropical species. Here, using a combination of biochemical, molecular, and chemical approaches, we decipher specific plant-feeding associations in field-collected sand flies from a dry ecology endemic for leishmaniasis in Kenya. Cold-anthrone test indicative of recent plant feeding showed that fructose positivity rates were similar in both sand fly sexes and between those sampled indoors and outdoors. Analysis of derived sequences of the ribulose-1,5-bisphosphate carboxylase large subunit gene (rbcL) from fructose-positive specimens implicated mainly Acacia plants in the family Fabaceae (73%) as those readily foraged on by both sexes of Phlebotomus and Sergentomyia. Chemical analysis by high performance liquid chromatography detected fructose as the most common sugar in sand flies and leaves of selected plant species in the Fabaceae family. Analysis of similarities (ANOSIM) of the headspace volatile profiles of selected Fabaceae plants identified benzyl alcohol, (Z)-linalool oxide, (E)-β-ocimene, p-cymene, p-cresol, and m-cresol, as discriminating compounds between the plant volatiles. These results indicate selective sand fly plant feeding and suggest that the discriminating volatile organic compounds could be exploited in attractive toxic sugar- and odor- bait technologies control strategies.     

Effects of surrounding landscape on parasitism of alfalfa aphids in an IPM crop system in northern Catalonia

The parasitism (Hymenoptera, Braconidae, Aphidiinae) of alfalfa aphids (Hemiptera, Aphididae) was determined during three crop growing seasons. The highest rates of parasitism of Acyrthosiphon pisum Harris and of Therioaphis trifolii Monell occurred during the first-second and the fourth alfalfa intercuts, respectively. The landscape surrounding the fields affected only parasitism rates of A. pisum. During the second intercut the forest area had a negative influence on parasitism rates, whereas the bordering surfaces of alfalfa and winter cereals had a positive influence. Positive correlations were found between the rates of parasitism of A. pisum and the rate of aphid population increase in the first intercut. By contrast, negative correlations were found in the second intercut, when the aphid population peaked, suggesting that parasitoids contribute to the regulation of the aphid. This study stresses that regulation of alfalfa aphids cannot be explained solely on the basis of one functional group of natural enemies.     

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.     

Neisseria meningitidis colonization of the brain endothelium and cerebrospinal fluid invasion

The brain and meningeal spaces are protected from bacterial invasion by the blood–brain barrier, formed by specialized endothelial cells and tight intercellular junctional complexes. However, once in the bloodstream, Neisseria meningitidis crosses this barrier in about 60% of the cases. This highlights the particular efficacy with which N. meningitidis targets the brain vascular cell wall. The first step of central nervous system invasion is the direct interaction between bacteria and endothelial cells. This step is mediated by the type IV pili, which induce a remodelling of the endothelial monolayer, leading to the opening of the intercellular space. In this review, strategies used by the bacteria to survive in the bloodstream, to colonize the brain vasculature and to cross the blood–brain barrier will be discussed.     

Positive association between thrips and spider mites in seedling cotton

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A unified framework for diversity gradients: the adaptive trait continuum

Aim Adaptive trait continua are axes of covariation observed in multivariate trait data for a given taxonomic group. These continua quantify and summarize life‐history variation at the inter‐specific level in multi‐specific assemblages. Here we examine whether trait continua can provide a useful framework to link life‐history variation with demographic and evolutionary processes in species richness gradients. Taking an altitudinal species richness gradient for Mediterranean butterflies as a study case, we examined a suite of traits (larval diet breadth, adult phenology, dispersal capacity and wing length) and species‐specific habitat measures (temperature and aridity breadth). We tested whether traits and species‐specific habitat measures tend to co‐vary, whether they are phylogenetically conserved, and whether they are able to explain species distributions and spatial genetic variation in a large number of butterfly assemblages. Location Catalonia, Spain. Methods We formulated predictions associated with species richness gradients and adaptive trait continua. We applied principal components analyses (PCAs), structural equation modelling and phylogenetic generalized least squares models. Results We found that traits and species‐specific habitat measures covaried along a main PCA axis, ranging from multivoltine trophic generalists with high dispersal capacity to univoltine (i.e. one generation per year), trophic specialist species with low dispersal capacity. This trait continuum was closely associated with the observed distributions along the altitudinal gradient and predicted inter‐specific differences in patterns of spatial genetic variability (F_ST and genetic distances), population responses to the impacts of global change and local turnover dynamics. Main conclusions The adaptive trait continuum of Mediterranean butterflies provides an integrative and mechanistic framework to: (1) analyse geographical gradients in species richness, (2) explain inter‐specific differences in population abundances, spatial distributions and demographic trends, (3) explain inter‐specific differences in patterns of genetic variation (F_ST and genetic distances), and (4) study specialist–generalist life‐history transitions frequently involved in butterfly diversification processes.