Multi-population QTL detection for aerial morphogenetic traits in the model legume <Emphasis Type="Italic">Medicago truncatula</Emphasis>

Medicago truncatula, as a model species, is useful to study the genetic control of traits of agronomic interest in legumes species. Aerial morphogenesis is a key component of forage and seed yield. It was measured in four mapping populations originating from five parental lines. Single and multi-population quantitative trait locus (QTL) detections were carried out. A large variation was observed within populations and transgressive segregation was noted. Most traits showed high heritabilities in all seasons. Length of primary branches (LPB, cm) was positively correlated to branch elongation rate (BER, cm day⁻¹) and aerial dry matter (ADM, g). Flowering time (FT, °C day⁻¹) showed negative correlations with length of main stem (LMS, cm) and BER. One hundred and forty-one QTLs for BER, LMS, FT, LPB, diameter of primary branches (DPB), number of primary branches (NPB), number of nodes (NI) and ADM were identified and localized over all eight chromosomes. Single and multi-population analyses showed that the most important regions for aerial morphogenetic traits were chromosomes 1, 2, 7 and 8. Multi-population analysis revealed three regions of major QTLs affecting aerial morphogenetic traits (LPB, LMS, NPB, BER and FT). A region involved in flowering time variation was revealed on chromosome 6 on a single population. These results were used to identify candidate genes that could control variation for aerial morphogenesis traits in this species and in related crop legume species.     

Acute leptin treatment enhances functional recovery after spinal cord injury

Background

Spinal cord injury is a major cause of long-term disability and has no current clinically accepted treatment. Leptin, an adipocyte-derived hormone, is best known as a regulator of food intake and energy expenditure. Interestingly, several studies have demonstrated that leptin has significant effects on proliferation and cell survival in different neuropathologies. Here, we sought to evaluate the role of leptin after spinal cord injury.

Findings

Based on its proposed neuroprotective role, we have evaluated the effects of a single, acute intraparenchymal injection of leptin in a clinically relevant animal model of spinal cord injury. As determined by quantitative Real Time-PCR, endogenous leptin and the long isoform of the leptin receptor genes show time-dependent variations in their expression in the healthy and injured adult spinal cord. Immunohistochemical analysis of post-injury tissue showed the long isoform of the leptin receptor expression in oligodendrocytes and, to a lesser extent, in astrocytes, microglia/macrophages and neurons. Moreover, leptin administered after spinal cord injury increased the expression of neuroprotective genes, reduced caspase-3 activity and decreased the expression of pro-inflammatory molecules. In addition, histological analysis performed at the completion of the study showed that leptin treatment reduced microglial reactivity and increased caudal myelin preservation, but it did not modulate astroglial reactivity. Consequently, leptin improved the recovery of sensory and locomotor functioning.

Conclusions

Our data suggest that leptin has a prominent neuroprotective and anti-inflammatory role in spinal cord damage and highlights leptin as a promising therapeutic agent.     

Exploring the pan-surfome of Streptococcus suis: Looking for common protein antigens

Streptococcus suis is a swine and human pathogen for which no commercial vaccine is still available. Conserved and broadly distributed surface proteins have become the chosen targets for the development of efficacious vaccines that could overcome the problems of non-heterologous protection of bacterins or capsule polysaccharide-based vaccines. In this work, we have analyzed by proteomics a collection of 39 strains obtained from infected pigs. The isolates belonged to 19 of the most prevalent serotypes during the last years. We have applied the "shaving" approach to define the "pan-surfome" or the set of both common and unique surface proteins identified in such strains. This set was constituted by 113 proteins. We have categorized them for their potential for further vaccination studies, based on their distribution among strains and their a priori accessibility to antibodies. According to these criteria, the cell-wall protein SsnA appears to be the best candidate from this list, as it was that with the widest distribution among the analyzed pathogen types, it showed to be highly immunogenic and highly accessible to antibodies, as demonstrated by flow cytometry.     

On the mechanism of Candida spp. photoinactivation by hypericin

The photoprocesses involved in hypericin photoinactivation of three different Candida species (C. albicans, C. parapsilosis and C. krusei) have been examined. Production of singlet oxygen from the triplet state and of superoxide from both the triplet state and the semiquinone radical anion are demonstrated. Hydrogen peroxide is formed downstream of these early events. The outcome of the photodynamic treatments is dictated by the intracellular distribution of hypericin, which is different in the three species and affects the ability of hypericin to produce the different reactive oxygen species and trigger cell-death pathways. The results are in line with the previously-observed different susceptibilities of the three Candida species to hypericin photodynamic treatments.     

Factors Associated with Leishmania Asymptomatic Infection: Results from a Cross-Sectional Survey in Highland Northern Ethiopia

Background

In northern Ethiopia the prevalence of visceral leishmaniasis is steadily rising posing an increasing public health concern. In order to develop effective control strategies on the transmission of the disease it is important to generate knowledge on the epidemiological determinants of the infection.

Methodology/Principal Findings

We conducted a cross-sectional survey on children 4–15 years of age using a multi staged stratified cluster sampling on high incidence sub-districts of Amhara regional state, Ethiopia. The survey included a socio-demographic, health and dietary questionnaire, and anthropometric measurements. We performed rK39-ICT and DAT serological tests in order to detect anti-Leishmania antibodies and carried out Leishmanin Skin Test (LST) using L.major antigen. Logistic regression models were used. Of the 565 children surveyed 56 children were positive to infection (9.9%). The individual variables that showed a positive association with infection were increasing age, being male and sleeping outside [adjusted odds ratios (95% CI): 1.15 (1.03, 1.29), 2.56 (1.19, 5.48) and 2.21 (1.03, 4.71) respectively] and in relation to the household: past history of VL in the family, living in a straw roofed house and if the family owned sheep [adjusted OR (95% CI): 2.92 (1.25, 6.81), 2.71 (1.21, 6.07) and 4.16 (1.41, 12.31) respectively].

Conclusions/Significance

A behavioural pattern like sleeping outside is determinant in the transmission of the infection in this area. Protective measures should be implemented against this identified risk activity. Results also suggest a geographical clustering and a household focalization of the infection. The behaviour of the vector in the area needs to be clarified in order to establish the role of domestic animals and house materials in the transmission of the infection.     

Complete genome sequence of the termite hindgut bacterium Spirochaeta coccoides type strain (SPN1(T)), reclassification in the genus Sphaerochaeta as Sphaerochaeta coccoides comb. nov. and emendations of the family Spirochaetaceae and the genus Sphaerochaeta

Spirochaeta coccoides Dröge et al. 2006 is a member of the genus Spirochaeta Ehrenberg 1835, one of the oldest named genera within the Bacteria. S. coccoides is an obligately anaerobic, Gram-negative, non-motile, spherical bacterium that was isolated from the hindgut contents of the termite Neotermes castaneus. The species is of interest because it may play an important role in the digestion of breakdown products from cellulose and hemicellulose in the termite gut. Here we provide a taxonomic re-evaluation for strain SPN1^T, and based on physiological and genomic characteristics, we propose its reclassification as a novel species in the genus Sphaerochaeta, a recently published sister group of the Spirochaeta. The 2,227,296 bp long genome of strain SPN1^T with its 1,866 protein-coding and 58 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Considering water availability and the effect of solute concentration on high solids saccharification of lignocellulosic biomass

Milliliter scale (ligno)cellulose saccharifications suggest general solute concentration and its impact on water availability plays a significant role in detrimental effects associated with high solids lignocellulose conversions. A microtumbler developed to enable free‐fall mixing at dry solids loadings up to 35% (w/w) repeatedly produced known detrimental conversion trends on cellulose, xylan and pretreated lignocellulose with commercial enzymes. Despite this, high concentrations of insoluble nonhydrolysable dextrans did not depress saccharification extents in 5% (w/w) cellulose slurries suggesting mass transfer limitations may not significantly limit hydrolysis extents at high solids loadings. Interestingly, cellulose saccharification by purified cellulases showed increased conversions with increasing dry solids loadings. This prompted investigations into impacts the concentration of soluble species, such as sugar alcohols, low molecular weight enzyme preparation components, and monomer hydrolysis products, have on the hydrolysis environment. Such substances significantly depress conversion rates and were shown to correlatively lower water activity (A_w) in the hydrolysis environment while high insoluble solids concentrations did not. Furthermore, low‐field NMR on concentrated slurries of insoluble complex carbohydrates, including the nonhydrolysable dextrans, showed all solids constrained water significantly more than high concentrations of soluble species (inhibitory) suggesting water constraint may not be as problematic an issue at high solids loadings compared to the availability of water in the system. Additionally, the introduction of soluble species lessened overall water constraint in high solids systems and appears to shift the distribution of water away from insoluble surfaces. This is potentially a critical issue for industrial processes operating at high dry solids levels. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Hypomethylation of cytosine residues in cold-sensitive regions of Cestrum strigilatum (Solanaceae)

Heterochromatin comprises a fraction of the genome usually with highly repeated DNA sequences and lacks of functional genes. This region can be revealed by using Giemsa C-banding, fluorochrome staining and cytomolecular tools. Some plant species are of particular interest through having a special type of heterochromatin denominated the cold-sensitive region (CSR). Independent of other chromosomal regions, when biological materials are subjected to low temperatures (about 0 °C), CSRs appear slightly stained and decondensed. In this study, we used Cestrum strigilatum (Solanaceae) to understand some aspects of CSR condensation associated with cytosine methylation levels, and to compare the behavior of different heterochromatin types of this species, when subjected to low temperatures.