Epigenetic repressor-like genes are differentially regulated during grapevine (Vitis vinifera L.) development

Grapevine sexual reproduction involves a seasonal separation between inflorescence primordia (flowering induction) and flower development. We hypothesized that a repression mechanism implicating epigenetic changes could play a role in the seasonal separation of these two developmental processes in grapevine. Therefore, the expression of five grapevine genes with homology to the Arabidopsis epigenetic repressor genes FERTILIZATION INDEPENDENT ENDOSPERM (FIE), EMBRYONIC FLOWER 2 (EMF2), CURLY LEAF (CLF), MULTICOPY SUPPRESSOR OF IRA 1 (MSI1) and SWINGER (SWN) was analyzed during the development of buds and vegetative and reproductive organs. During bud development, the putative grapevine epigenetic repressor genes VvCLF, VvEMF2, VvMSI1, VvSWN and VvFIE are mainly expressed in latent buds at the flowering induction period, but also detected during bud burst and inflorescence/flower development. The overlapping expression patterns of grapevine PcG-like genes in buds suggest that chromatin remodeling mechanisms could be operating during grapevine bud development for controlling processes such as seasonal flowering, dormancy and bud burst. Furthermore, the expression of grapevine PcG-like genes was also detected in fruits and vegetative organs, suggesting that epigenetic changes could be at the basis of the regulation of various proliferation–differentiation cell transitions that occur during grapevine development.     

Bicyclic carbamates as inhibitors of papain-like cathepsin proteases

A 6-oxa-1-aza-bicyclo[3.2.1]octan-7-one system inhibits the proteolytic activity of several cysteine proteases belonging to the papain family. In vitro mechanistic studies and in silico calculations suggest that the minimal pi-overlap between the bridgehead nitrogen and the carbonyl leads to a considerable weakening of the urethane system, making it susceptible to nucleophilic attack from the active site thiol group. The resulting covalent adduct is slowly hydrolyzed, releasing the hydroxypiperidine product of the inhibitor. Synthesis and testing of a set of analogs led to variable protease subtype selectivities ranging from micromolar to nanomolar potencies.     

Ready-to-use DNA extracted with a CTAB method adapted for herbarium specimens and mucilaginous plant tissue

This report summarizes major changes in previously published protocols for DNA extraction to improve the quality of DNA extracted from plants. Here, we highlight the critical modifications in the original protocols. The efficiency of these changes results in high-quality DNA ready to use in a variety of phytogenetically distant plant families, in particular species with mucopolysaccharides. The DNA obtained can be used without further purification in various molecular biology assays, including direct sequencing and AFLP and RAPD (random-amplified polymorphic DNA) analyses. The effectiveness of this method is proven by the amplification and sequencing of PCR products of up to 1 kb with DNA extracted from herbarium tissue ≥60 years old. This versatility is not usually found in DNA extraction protocols. In addition, this method is quick, adaptable to standard laboratories, and most important, safer and more cost-effective.     

Novel Cell-Free Strategy for Therapeutic Angiogenesis: In Vitro Generated Conditioned Medium Can Replace Progenitor Cell Transplantation

Background

Current evidence suggests that endothelial progenitor cells (EPC) contribute to ischemic tissue repair by both secretion of paracrine factors and incorporation into developing vessels. We tested the hypothesis that cell-free administration of paracrine factors secreted by cultured EPC may achieve an angiogenic effect equivalent to cell therapy.

Methodology/Principal Findings

EPC-derived conditioned medium (EPC-CM) was obtained from culture expanded EPC subjected to 72 hours of hypoxia. In vitro, EPC-CM significantly inhibited apoptosis of mature endothelial cells and promoted angiogenesis in a rat aortic ring assay. The therapeutic potential of EPC-CM as compared to EPC transplantation was evaluated in a rat model of chronic hindlimb ischemia. Serial intramuscular injections of EPC-CM and EPC both significantly increased hindlimb blood flow assessed by laser Doppler (81.2±2.9% and 83.7±3.0% vs. 53.5±2.4% of normal, P<0.01) and improved muscle performance. A significantly increased capillary density (1.62±0.03 and 1.68±0.05/muscle fiber, P<0.05), enhanced vascular maturation (8.6±0.3 and 8.1±0.4/HPF, P<0.05) and muscle viability corroborated the findings of improved hindlimb perfusion and muscle function. Furthermore, EPC-CM transplantation stimulated the mobilization of bone marrow (BM)-derived EPC compared to control (678.7±44.1 vs. 340.0±29.1 CD34⁺/CD45⁻ cells/1×10⁵ mononuclear cells, P<0.05) and their recruitment to the ischemic muscles (5.9±0.7 vs. 2.6±0.4 CD34⁺ cells/HPF, P<0.001) 3 days after the last injection.

Conclusions/Significance

Intramuscular injection of EPC-CM is as effective as cell transplantation for promoting tissue revascularization and functional recovery. Owing to the technical and practical limitations of cell therapy, cell free conditioned media may represent a potent alternative for therapeutic angiogenesis in ischemic cardiovascular diseases.     

The effects of l-DOPA on root growth, lignification and enzyme activity in soybean seedlings

In the present study, we investigated the effects of l-DOPA (l-3,4-dihydroxyphenylalanine), an allelochemical exuded from the velvetbean (Mucuna pruriens L DC. var. utilis), on the growth and cell viability of soybean (Glycine max L. Merrill) roots. We analyzed the effects of l-DOPA on phenylalanine ammonia lyase (PAL), cinnamyl-alcohol dehydrogenase (CAD) and cell wall-bound peroxidase (POD) activities as well as its effects on phenylalanine, tyrosine and lignin contents in the roots. 3-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0), with or without 0.5?mM l-DOPA, in a growth chamber at 25?°C for 6, 12, 18 or 24?h with a day/night regime of 1:1, and a photon flux density of 280???mol?m^?2 s^?1. In general, the length, fresh weight and dry weight of the roots decreased followed by a significant loss of cell viability. Phenylalanine, tyrosine and lignin contents as well as PAL, CAD and cell wall-bound POD activities increased after l-DOPA treatment. These results reinforce the susceptibility of soybean to l-DOPA, which increases the enzyme activity in the phenylpropanoid pathway and, therefore, provides precursors for the polymerization of lignin. In brief, these findings suggest that the inhibition of soybean root growth induced by exogenously applied l-DOPA may be due to excessive production of lignin in the cell wall.     

IL-17RA Signaling Reduces Inflammation and Mortality during Trypanosoma cruzi Infection by Recruiting Suppressive IL-10-Producing Neutrophils

Members of the IL-17 cytokine family play an important role in protection against pathogens through the induction of different effector mechanisms. We determined that IL-17A, IL-17E and IL-17F are produced during the acute phase of T. cruzi infection. Using IL-17RA knockout (KO) mice, we demonstrate that IL-17RA, the common receptor subunit for many IL-17 family members, is required for host resistance during T. cruzi infection. Furthermore, infected IL-17RA KO mice that lack of response to several IL-17 cytokines showed amplified inflammatory responses with exuberant IFN-γ and TNF production that promoted hepatic damage and mortality. Absence of IL-17RA during T. cruzi infection resulted in reduced CXCL1 and CXCL2 expression in spleen and liver and limited neutrophil recruitment. T. cruzi-stimulated neutrophils secreted IL-10 and showed an IL-10-dependent suppressive phenotype in vitro inhibiting T-cell proliferation and IFN-γ production. Specific depletion of Ly-6G+ neutrophils in vivo during T. cruzi infection raised parasitemia and serum IFN-γ concentration and resulted in increased liver pathology in WT mice and overwhelming wasting disease in IL-17RA KO mice. Adoptively transferred neutrophils were unable to migrate to tissues and to restore resistant phenotype in infected IL-17RA KO mice but migrated to spleen and liver of infected WT mice and downregulated IFN-γ production and increased survival in an IL-10 dependent manner. Our results underscore the role of IL-17RA in the modulation of IFN-γ-mediated inflammatory responses during infections and uncover a previously unrecognized regulatory mechanism that involves the IL-17RA-mediated recruitment of suppressive IL-10-producing neutrophils.     

Sustained Reduction of the Dengue Vector Population Resulting from an Integrated Control Strategy Applied in Two Brazilian Cities

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008–2009, with 96.8%–100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program’s success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program.     

Chromosome number variation and polyploidy in the genus Echinocereus (Cactaceae)

Analyses of meiotic and mitotic chromosomes were undertaken in 16 taxa of Echinocereus belonging to 12 species and all seven taxonomic sections (sensu Taylor). Chromosome numbers are reported for the first time for eight taxa, and previously published chromosome counts are confirmed for the remaining eight. Both diploid and polyploid counts were obtained. Eleven (69%) of the taxa surveyed were diploid (2n = 22); the five varieties of E. engelmannii were polyploid (2n = 44). Overall, chromosome counts are available for 23 of the 48 proposed species (sensu Taylor). Of these, 19 (82%) are diploid, and four (18%) are polyploid. Polyploid cytotypes are most common in the primitive sections, e.g., sections Erecti and Triglochidiatus, which suggests that polyploidy is probably a derived condition in Echinocereus. Polyploid taxa range from medium to high latitudes and elevations relative to the overall distribution of the genus. Polyploidy, hybridization, and cryptic chromosomal rearrangements are thought to be the major causes of the speciation events of the genus.     

Diversity of Saxicolous Lichens along an Aridity Gradient in Central México

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate change. However, our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still limited. To evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland, a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro, Mexico, comprising ten sampling sites with a 10 km separation. Species richness, abundance and diversity of soil lichen species were recorded using two sampling methods: the quadrat-intercept and the line-intercept method, to compare their performance in assessing soil lichen diversity in drylands. The number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index (AI = 0.10–0.34). Quadrat intercept and point intercept methods gave quite similar results, which means that the selected method does not influence the results in a significant way. This study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.