Building Blocks for Synthesis of Oligoarabinonucleotides: Preparation of Arabinonucleoside H-Phosphonates from Protected Ribonucleosides

Abstract

A straightforward and inexpensive synthesis of arabinonucleoside H-phosphonates has been developed. Arabinonucleosides were synthesised from protected ribonucleosides via 2′-keto derivatives. Reaction conditions have been optimised for compounds bearing labile N-protections. Further protecting group manipulation and phosphonylation gave the required H-phosphonate monomers.     

Shifting Pacific storm tracks as stressors to ecosystems of western North America

Much of the precipitation delivered to western North America arrives during the cool season via midlatitude Pacific storm tracks, which may experience future shifts in response to climate change. Here, we assess the sensitivity of the hydroclimate and ecosystems of western North America to the latitudinal position of cool‐season Pacific storm tracks. We calculated correlations between storm track variability and three hydroclimatic variables: gridded cool‐season standardized precipitation‐evapotranspiration index, April snow water equivalent, and water year streamflow from a network of USGS stream gauges. To assess how historical storm track variability affected ecosystem processes, we derived forest growth estimates from a large network of tree‐ring widths and land surface phenology and wildfire estimates from remote sensing. From 1980 to 2014, cool‐season storm tracks entered western North America between approximately 41°N and 53°N. Cool‐season moisture supply and snowpack responded strongly to storm track position, with positive correlations to storm track latitude in eastern Alaska and northwestern Canada but negative correlations in the northwestern U.S. Ecosystems of the western United States were greener and more productive following winters with south‐shifted storm tracks, while Canadian ecosystems were greener in years when the cool‐season storm track was shifted to the north. On average, larger areas of the northwestern United States were burned by moderate to high severity wildfires when storm tracks were displaced north, and the average burn area per fire also tended to be higher in years with north‐shifted storm tracks. These results suggest that projected shifts of Pacific storm tracks over the 21st century would likely alter hydroclimatic and ecological regimes in western North America, particularly in the northwestern United States, where moisture supply and ecosystem processes are highly sensitive to the position of cool‐season storm tracks.     

A novel strategy for the functional cloning of enzymes using filamentous phage display: the case of nucleotidyl transferases

In vitro selections for catalytic activity have been designed for the isolation of genes encoding enzymes from libraries of proteins displayed on filamentous phages. The proteins are generally expressed as C-terminal fusions with the N-terminus of the minor coat protein p3 for display on phages. As full-length cDNAs generally contain several stop codons near their 3′ end, this approach cannot be used for their expression on the surface of phages. Here we show that in vitro selection for catalytic activity is compatible with a system for expression of proteins as N-terminal fusions on the surface of bacteriophages. It is highlighted for the Stoffel fragment of Taq DNA polymerase I and makes use of (p3–Jun/Fos–Stoffel fragment) fusions. The efficiency of the selection is measured by an enrichment factor found to be about 55 for a phage polymerase versus a phage not expressing a polymerase. This approach could provide a method for the functional cloning of nucleotidyl transferases from cDNA libraries using filamentous phage display.     

Morphological study for understanding the sexual pattern in ghost shrimp Callichirus major (Crustacea: Axiidea)

Callichirus major is a species of ghost shrimp that has burrowing habits, building underground galleries in the intertidal region of beaches. This study aimed to analyse some morphological parameters to verify its type of sexual pattern. A sample of 79 individuals, collected at the beach of Corujão, Espírito Santo, Brazil, was used. Data on the external morphology, presence of gonopores, carapace length (CL) and cheliped lengths (Lch) were obtained. In addition, the gonads were processed for histological analysis. The animals were divided into three categories: A, individuals with male characteristics; B, those presenting exclusively female characteristics; C, animals with characteristics of intersex, which presented supernumerary gonopores. Positive allometries were found for Lch versus CL only for category A, characterizing the group's marked heterochely. Histologically, it was possible to observe the presence of oocytes in category A and one case of male tissue in an intersex individual (category C). However, no genital ducts of both sexes were found in that individual. Callichirus major presents controversial sexual characters, which makes it difficult to understand the reproductive parameters and sexual pattern. However, maybe that species can develop a sexual system of hermaphroditism.     

Stimulation of the secretion of pro-inflammatory cytokines by Bifidobacterium strains

To characterize the ability of bifidobacteria to affect the production of macrophage-derived cytokines, a murine macrophage-like cell line, J774.1, was cultured in the presence of 27 strains of heat-inactivated bifidobacteria. Bifidobacterium adolescentis and B. longum, known as adult-type bifidobacteria, induced significantly more pro-inflammatory cytokine secretion, IL-12 and TNF-alpha, by J774.1 cells, than did the infant-type bifidobacteria, B. bifidum, B. breve, and B. infantis (P<0.01). In contrast, B. adolescentis did not stimulate the production of anti-inflammatory IL-10 from J774.1 cells as the other tested bacteria did. The results suggest that the adult-type bifidobacteria, especially B. adolescentis, may be more potent to amplify but less able to down-regulate the inflammatory response.     

Standardization of the method proposed by the World Health Organization for determining the susceptibility levels of leishmaniasis vectors to insecticides

The WHO method for determining insecticide resistance was standardized for several species of Lutzomyia sand flies under laboratory and field conditions. The biological assays were applied solely to optimize the conditions for the control, i.e., without insecticide, and to estimate mortality due to handling or other unfavorable conditions. Adult female flies from 3 laboratory colonies and one field strain were tested: two laboratory strains of Lutzomyia longipalpis, one laboratory strain of Lutzomyia serrana and one field-collected strain of Lutzomyia quasitownsendi. The WHO method was compared with one modified in which, during the post-exposure period, the recommended plain tube apparatus was replaced with a plastic container layered with damp plaster of Paris. Three paper substrate types were compared under each condition: olive oil additive, silicon oil additive and plain paper. The measured variable was percent mortality in 24 h. For the WHO protocol, the L. longipalpis strains indicated a 0-10% mortality, L. serrana 20-80% and L. quasitownsendi 10-50%. With the modified WHO apparatus, the average mortality was < 4% for all species. No significant differences were observed among the paper treatments. These results indicate a strong species-specific effect of post-exposure conditions on sand flies. To establish baseline levels of insecticide resistance in Lutzomyia sand flies, the WHO method is recommended only for L. longipalpis, and the modified method for L. serrana, L. quasitownsendi and closely related species.     

Characterization of a phosphatase secreted by Staphylococcus aureus strain 154, a new member of the bacterial class C family of nonspecific acid phosphatases

An acid phosphatase, designated SapS, hydrolyzing p-nitrophenyl phosphate (pNPP), was identified and characterized from the culture supernatant of a Staphylococcus aureus strain isolated from vegetables. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the protein indicated an estimated molecular mass of 30 kDa. The enzyme displayed optimum activity at 40 degrees C and pH 5. Characterization of the phosphatase in a reconstitution assay showed that MgCl2 and Triton X-100, respectively, restored maximal activity, but not CaCl2 The phosphatase activity was affected by EDTA and sodium molybdate. The DNA sequence encoding SapS was cloned and sequenced. The putative acid phosphatase gene encodes a protein of 296 amino acids with a 31-residue signal peptide. Database searches revealed significant structural homology of SapS to several proteins belonging to the bacterial class C family of nonspecific acid phosphatases. Comparison of the sequences indicated that despite a low level of overall conservation between the proteins, four conserved sequence motifs could be identified.     

A novel tomato mutant,Solanum lycopersicum elongated fruit1 (Slelf1), exhibits an elongated fruit shape caused by increased cell layers in the proximal region of the ovary

Genes controlling fruit morphology offer important insights into patterns and mechanisms determining organ shape and size. In cultivated tomato (Solanum lycopersicum L.), a variety of fruit shapes are displayed, including round-, bell pepper-, pear-, and elongate-shaped forms. In this study, we characterized a tomato mutant possessing elongated fruit morphology by histologically analyzing its fruit structure and genetically analyzing and mapping the genetic locus. The mutant line, Solanum lycopersicum elongated fruit 1 (Slelf1), was selected in a previous study from an ethylmethane sulfonate-mutagenized population generated in the background of Micro-Tom, a dwarf and rapid-growth variety. Histological analysis of the Slelf1 mutant revealed dramatically increased elongation of ovary and fruit. Until 6 days before flowering, ovaries were round and they began to elongate afterward. We also determined pericarp thickness and the number of cell layers in three designated fruit regions. We found that mesocarp thickness, as well as the number of cell layers, was increased in the proximal region of immature green fruits, making this the key sector of fruit elongation. Using 262 F₂ individuals derived from a cross between Slelf1 and the cultivar Ailsa Craig, we constructed a genetic map, simple sequence repeat (SSR), cleaved amplified polymorphism sequence (CAPS), and derived CAPS (dCAPS) markers and mapped to the 12 tomato chromosomes. Genetic mapping placed the candidate gene locus within a 0.2?Mbp interval on the long arm of chromosome 8 and was likely different from previously known loci affecting fruit shape.     

Seed size,number and strategies in annual plants: a comparative functional analysis and synthesis

Background and AimsPlants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size.MethodsUsing published values of comparative seed number as the ‘gold standard’ and a large functional database, comparative seed yield and number per plant and per m² were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora.Key ResultsAs predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m² was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the ‘gold standard’ predictor used. Moreover, regressions estimating comparative seed yield per m² achieved low precision.ConclusionsFor the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. ‘Regenerative trait-based ecology’ remains in its infancy, with work needed on determinate vs. indeterminate flowering (‘bet-hedging’), C-S-R methodologies, phylogeny, comparative seed yield per m² and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance ‘regenerative trait-based ecology’ to the next level.     

Acceptance and perceived barriers of implementing a guideline for managing low back in general practice

Background

There is considerable interest today in shared decision-making (SDM), defined as a decision-making process jointly shared by patients and their health care provider. However, the data show that SDM has not been broadly adopted yet. Consequently, the main goal of this proposal is to bring together the resources and the expertise needed to develop an interdisciplinary and international research team on the implementation of SDM in clinical practice using a theory-based dyadic perspective.

Methods

Participants include researchers from Canada, US, UK, and Netherlands, representing medicine, nursing, psychology, community health and epidemiology. In order to develop a collaborative research network that takes advantage of the expertise of the team members, the following research activities are planned: 1) establish networking and on-going communication through internet-based forum, conference calls, and a bi-weekly e-bulletin; 2) hold a two-day workshop with two key experts (one in theoretical underpinnings of behavioral change, and a second in dyadic data analysis), and invite all investigators to present their views on the challenges related to the implementation of SDM in clinical practices; 3) conduct a secondary analyses of existing dyadic datasets to ensure that discussion among team members is grounded in empirical data; 4) build capacity with involvement of graduate students in the workshop and online forum; and 5) elaborate a position paper and an international multi-site study protocol.

Discussion

This study protocol aims to inform researchers, educators, and clinicians interested in improving their understanding of effective strategies to implement shared decision-making in clinical practice using a theory-based dyadic perspective.