Use of climatic data and satellite imagery to model the abundance of Culicoides imicola, the vector of African horse sickness virus, in Morocco

African horse sickness (AHS) is a vector-borne, infectious disease of equids caused by African horse sickness virus (AHSV) . The only proven field vector of the virus is the biting midge Culicoides imicola. Following a recent epizootic (1989–91) of AHS in Morocco, light traps and automatic weather stations were operated for 2 years at twenty-two sites distributed over much of the country. The annually-averaged mean daily trap catch of C. imicola at these sites was negatively correlated with wind speed, and positively correlated with the average and mean annual minimum NDVI (Normalized Difference Vegetation Index, a remotely sensed measure of vegetation activity). There were no significant correlations between the mean daily trap catch and air temperature, soil temperature, relative humidity, saturation deficit, rainfall, altitude or the mean annual maximum or range of NDVI. The best two-variable model, which combined Windspeed_MnAvMn (the average daily minimum wind speed of the least windy month) and NDVI_min (the average annual minimum NDVI) as predictors, explained over 50% of the variance in the annually-averaged mean daily trap catch of C. imicola. There was a significant, positive correlation between minimum wind speed at night and the daily mortality rate of adult female C. imicola and it is suggested that the relationship between wind speed and the abundance of C. imicola arises from effects on adult mortality or dispersal. Considering several climatic variables, in North Africa NDVI_min was most significantly correlated with total annual rainfall. It is suggested that the relationship between NDVI_min and the abundance of C. imicola arises from the impact of soil moisture on both. It is proposed that areas of Morocco with higher levels of soil moisture in late summer or autumn provide more, larger and/or more enduring breeding sites for C. imicola, as well as supporting more photosynthetically active vegetation and hence having higher NDVI.     

Synthesis and Biological Evaluation of 2-Carbamoyl-5-D-Ribofuranosylpyridine

Abstract

In order to study the influence of the position of both the carbamoyl and the D-ribofuranosylmoiety on the biological activity of pyridine-C-nucleosides, the 2-carbamoyl-5-P-D-ribofuranosylpyridine was synthesized.     

Mutation-independent Proteomic Signatures of Pathological Progression in Murine Models of Duchenne Muscular Dystrophy

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Highlights

• •Proteomics analysis was performed in two murine models of Duchenne muscular dystrophy (mdx and mdx52) at three ages (8, 16 and 80 weeks) and compared with wild-type controls.
• •High-resolution isoelectric focusing liquid chromatography-tandem mass spectrometry enabled the quantification of 4974 proteins in all samples.
• •This study has revealed protein signatures of dystrophin deficiency and the progression of dystrophic pathology.
• •In contrast, the proteomes of the mdx and mdx52 mice were highly similar.
• •Pathway analysis revealed crosstalk between inflammatory, metabolic and muscle growth processes in dystrophic muscle.

     

Genetic footprints of late Quaternary climate change in the diversity of Patagonian‐Fueguian rodents

Species are impacted by climate change at both ecological and evolutionary time scales. Studies in northern continents have provided abundant evidence of dramatic shifts in distributions of species subsequent to the last glacial maximum (LGM), particularly at high latitudes. However, little is known about the history of southern continents, especially at high latitudes. South America is the only continent, other than Antarctica, that extends beyond 40 °S. Genetic studies of a few Patagonian species have provided seemingly conflicting results, indicating either postglacial colonization from restricted glacial refugia or persistence through glacial cycles and in situ differentiation. Using mitochondrial DNA sequences of 14 species of sigmodontine rodents, a major faunal ensemble of Patagonia and Tierra del Fuego, we show that at least nine of these species bear genetic footprints of demographic expansion from single restricted sources. However, timing of demographic expansion precedes the LGM in most of these species. Four species are fragmented phylogeographically within the region. Our results indicate that (i) demographic instability in response to historical climate change has been widespread in the Patagonian‐Fueguian region, and is generally more pronounced at high latitudes in both southern and northern continents; (ii) colonization from lower latitudes is an important component of current Patagonian‐Fueguian diversity; but (iii) in situ differentiation has also contributed to species diversity.     

A cyanobacterial bloom prevents fish trophic cascades

1. We experimentally compared the impacts of visually feeding zooplanktivorous fish and filter‐feeding omnivorous fish in shallow tropical Dakar Bango reservoir, Senegal. We provoked a cyanobacterial Anabaena bloom under mesotrophic to eutrophic N‐limited conditions in 18 enclosures assigned to six Nile tilapia life‐stage treatments, at typical biomasses: fishless control (C), zooplanktivorous fry (Z), omnivorous juveniles (O), herbivorous fingerlings (H) and two combinations (OZ, OH). 2. All fish grew well, but as prevalent inedible phytoplankton dampened fish effects, community‐level trophic cascades did not occur. Planktivore types acted independently and affected differentially the biomasses of total zooplankton, cyclopoids, nauplii, cladocerans, invertebrate carnivores, large herbivores, colonial cyanobacteria and Chlorophyta. They neither influenced the total biomass of phytoplankton, nor most water chemistry characteristics. Responses were apparently not fish‐biomass related. The bloom collapsed synchronously in all enclosures, coinciding with enrichment ending, with a return to clear water within 12 days. 3. Our results support the hypothesis that excess nutrients and prevalent inedible cyanobacteria inhibit the cascading effects of natural biomass levels of both visually feeding zooplanktivores and filter‐feeding omnivores. In N‐limited meso‐eutrophic shallow tropical lakes with predominantly small herbivorous zooplankton, neither the type nor the biomass of planktivorous fish present seems likely to prevent the transient outburst of cyanobacterial blooms. Such fragile ecosystems may thus not sustain a trophic state suitable for drinking water production, unless human impacts are restricted. The generality of restoration approaches based on ecological engineering should be further explored.     

Changes in antioxidant activities and phenol content in tomato plants subjected to partial root drying and regulated deficit irrigation

Abstract

Partial rootzone drying (PRD) and regulated deficit irrigation (RDI) are water saving irrigation systems that have been developed to increase water use efficiency (WUE) without significant yield reduction. To examine whether tomato responded differently to RDI and PRD, we compared the changes in antioxidative defenses in tomato plants using a split-root system. Tomato plants were grown for 21 days under controlled conditions with their roots separated equally between two soil compartments. Three irrigation treatments were imposed: Control, receiving an amount of water equivalent to 100% of plant transpiration; PRD in which one compartment was watered with 50% of the amount of water supplied to the controls, allowing one-half of the root system to be exposed to dry soil, and switching irrigation between sides weekly; RDI in which 50% of the amount of water given to the controls was supplied, half to each side of the root system. Relative water content (RWC), midday leaf Ψ and chlorophyll content decreased largely in RDI-treated plants, whereas the PRD plants exhibited relatively higher Ψ and RWC values. An enhanced level of lipid peroxidation in both roots and leaves indicated that PRD and RDI caused oxidative stress in tomato plants. In leaves, superoxide dismutase (SOD), soluble peroxidase (POX) and polyphenol oxidase (PPO) activities showed an increase in the early phase of water deficit, and then decreased in the remaining phase of the drying cycle. However, the increase was more pronounced under RDI. Catalase (CAT) activity declined continuously from the onset of PRD and RDI treatments to below the control level, and the reduction was less under PRD than RDI. POX cell-wall associated activities exceeded the control level by 450% and 230%, respectively, under RDI and PRD. At the root level, while CAT activity also decreased under both PRD and RDI, the activities of SOD, POX and PPO significantly increased and their activities showed an alternating increase/decrease paralleling the alternating irrigation in PRD-treated roots. As a result of the difference in POX and PPO activities between the two water treatments applied, PRD-treated plants accumulated more soluble and cell-wall bound phenolic compounds.     

Synthesis and Biological Evaluation of 4-Carbamoyl-2-β-D-Ribofuranosyl-Pyridine

Abstract

D-Allo/D-altro 2-(2,4:3, 5-di-O-benzylidenepentitol-1-y1)-4-(4,4-dimethyloxazolin-2-y1)pyridine was synthesized from 2-lithio-4-(4,4-dimethyloxazolin-2-y1)pyridine and 2, 4:3,5-di-O-benzylidenealdehydo-D-ribose. After mesylation and subsequent treatment of the adduct with CF₃COOH/H₂O and then ammonia, 4-carbamoyl-2-D-ribofuranosylpyridine was formed. The α- and β-anomers were separated by semipreparative hplc on a LICHROSORB 10 DIOL column. The β-anomer had no antiviral activity, but it had modest cytostatic activity against tumor cells.     

Synthesis and Biological Evaluation of Some D-Arabino- and D-Lyxofuranosyl-Pyridine C-Nucleosides

Abstract

The addition reaction of either 3-bromo-5-lithiopyridine (2a) or 3-cyano-5-lithiopyridine (2b) to 2,3:4,5-di-O-isopropylidene-aldehydo-D-arabinose (1) or 2,4:3,5-di-O-benzylidene-aldehydo-D-lyxose (8) gave respectively a D-gluco/D-manno mixture of 3-bromo- and 3-cyano-5-(2,3:4,5-di-O-isopropylidene-pentitol-1-yl)pyridine (3a,b) or a D-galacto/D-talo mixture of respectively 3-bromo- and 3-cyano-5-(2,4:3,5-di-O-benzylidene-pentitol-1-yl)pyridine (9a,b). Mesylation of C-1′ followed by reaction with CF₃COOH/H₂O resulted in the formation of the corresponding D-arabino- or D-lyxofuranosyl pyridine C-nucleosides. The cyano group of (5b) and (11b) was converted into a carbamoyl group using Amberlite IRA 400 (OH^?). 3-Cyano-5-D-arabinofuianosylpyridine (5b) was converted into 3-thiocarbamoyl-5-D-arabinofuranosyl-pyridine (7) using H₂S and triethylamine.

None of the test compounds showed a marked cytostatic or antiviral activity in vitro.     

DockRank: Ranking docked conformations using partner‐specific sequence homology‐based protein interface prediction

Selecting near‐native conformations from the immense number of conformations generated by docking programs remains a major challenge in molecular docking. We introduce DockRank, a novel approach to scoring docked conformations based on the degree to which the interface residues of the docked conformation match a set of predicted interface residues. DockRank uses interface residues predicted by partner‐specific sequence homology‐based protein–protein interface predictor (PS‐HomPPI), which predicts the interface residues of a query protein with a specific interaction partner. We compared the performance of DockRank with several state‐of‐the‐art docking scoring functions using Success Rate (the percentage of cases that have at least one near‐native conformation among the top m conformations) and Hit Rate (the percentage of near‐native conformations that are included among the top m conformations). In cases where it is possible to obtain partner‐specific (PS) interface predictions from PS‐HomPPI, DockRank consistently outperforms both (i) ZRank and IRAD, two state‐of‐the‐art energy‐based scoring functions (improving Success Rate by up to 4‐fold); and (ii) Variants of DockRank that use predicted interface residues obtained from several protein interface predictors that do not take into account the binding partner in making interface predictions (improving success rate by up to 39‐fold). The latter result underscores the importance of using partner‐specific interface residues in scoring docked conformations. We show that DockRank, when used to re‐rank the conformations returned by ClusPro, improves upon the original ClusPro rankings in terms of both Success Rate and Hit Rate. DockRank is available as a server at http://einstein.cs.iastate.edu/DockRank/ . Proteins 2014; 82:250–267. © 2013 Wiley Periodicals, Inc.