Sucrose effect on broomrape (Orobanche crenata) development on narbon bean (Vicia narbonensis L.)

The growth and development of broomrapes (Orobanche spp.) fully depends on the nutritional connection established between the parasitic plant and the root of the corresponding host plant. In thepresent study, narbon bean plants infected with Orobanche crenata were watered with different concentrations of sucrose (0.014, 0.044, 0.088 and 0.146 M) in order to evaluate its effect on the earlygrowth stages of the parasite. The germination of O. crenata seeds decreased with increasing sucrose concentrations and the number of infection attachments of crenata broomrapes decreased significantlywhen sucrose was present. A parallel experiment was conducted with identical sorbitol concentrations in order to determinate the role of the osmotic potential in the inhibition of the parasite growth. Ourresults showed that while low sucrose concentrations significantly reduced seed germination in O. crenata, similar concentrations of sorbitol have no significant effect thus indicating that the effect ofsucrose is not simply osmotic. Sucrose phytotoxicity was also studied by considering the dry weight of the host plants

Effects of Excess Brain-Derived Human α-Synuclein on Synaptic Vesicle Trafficking

α-Synuclein is a presynaptic protein that regulates synaptic vesicle trafficking under physiological conditions. However, in several neurodegenerative diseases, including Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy, α-synuclein accumulates throughout the neuron, including at synapses, leading to altered synaptic function, neurotoxicity, and motor, cognitive, and autonomic dysfunction. Neurons typically contain both monomeric and multimeric forms of α-synuclein, and it is generally accepted that disrupting the balance between them promotes aggregation and neurotoxicity. However, it remains unclear how distinct molecular species of α-synuclein affect synapses where α-synuclein is normally expressed. Using the lamprey reticulospinal synapse model, we previously showed that acute introduction of excess recombinant monomeric or dimeric α-synuclein impaired distinct stages of clathrin-mediated synaptic vesicle endocytosis, leading to a loss of synaptic vesicles. Here, we expand this knowledge by investigating the effects of native, physiological α-synuclein isolated from the brain of a neuropathologically normal human subject, which comprised predominantly helically folded multimeric α-synuclein with a minor component of monomeric α-synuclein. After acute introduction of excess brain-derived human α-synuclein, there was a moderate reduction in the synaptic vesicle cluster and an increase in the number of large, atypical vesicles called “cisternae.” In addition, brain-derived α-synuclein increased synaptic vesicle and cisternae sizes and induced atypical fusion/fission events at the active zone. In contrast to monomeric or dimeric α-synuclein, the brain-derived multimeric α-synuclein did not appear to alter clathrin-mediated synaptic vesicle endocytosis. Taken together, these data suggest that excess brain-derived human α-synuclein impairs intracellular vesicle trafficking and further corroborate the idea that different molecular species of α-synuclein produce distinct trafficking defects at synapses. These findings provide insights into the mechanisms by which excess α-synuclein contributes to synaptic deficits and disease phenotypes

Biocrust restoration: a key tool to recover degraded arid ecosystem functioning

peer reviewedBiocrusts are autotroph and heterotroph communities that cover 12% of the Earth land’s surface, where they act as ecosystem engineers. They are very vulnerable to climate change and disturbance caused by different anthropic activities. In this work, we revise the impacts of both disturbance types, which negatively affect biogeochemical cycles and water and energy balances, accelerate erosion processes and dust emissions, and decrease biodiversity, reducing ecosystem ability to provide services. We also explore the ability of these communities to recover after disturbance, which in general requires long time periods for the most developed communities. Because of this, new biotechnologies have emerged to accelerate their restoration, based on the inoculation of biocrust-forming organisms. Results from two main strategies according to the origin of the biocrust propagules used are revised: a) translocation of biocrust fragments from a donor area to the degraded area. This strategy is recommended for planned activities in which the existing biocrust before disturbance is applied; b) large-scale cultivation of biocrust-forming organisms (cyanobacteria, lichens, mosses or the whole community) in laboratory or greenhouse conditions for their later inoculation in the degraded area. Finally, we identify future challenges to maximize restoration success and biocrust conservation

Electron-withdrawing ability tunable polyphosphazene frameworks as novel heterogeneous catalysts for efficient biomass upgrading

A series of polyphosphazene nano-frameworks with electron-withdrawing capability have been produced and exhibited high activity as non-acidic heterogeneous catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions with good stability and recyclability. The unique cyclotriphosphazene unit and electron-withdrawing nature of the polymer backbone are essential for the catalytic performance

Ecohydrology and ecosystem services of a natural and an artificial bofedal wetland in the central Andes

High-altitude wetlands of the Central Andes, locally known as bofedales, provide important ecosystem services, particularly carbon storage, forage provisioning, and water regulation. Local communities have artificially expanded bofedales by irrigating surrounding grasslands to maximise areas for alpaca grazing. Despite their importance, biophysical processes of both natural and artificial bofedales are still poorly studied, which hinders the development of adequate management and conservation strategies. We analyse and compare the vegetation composition, hydrological variables, groundwater chemistry, and soil characteristics of a natural and an artificial bofedal of at least 10 years old in southern Peru, to understand their interrelations and the consequences for ecosystem service provisioning. We do not find statistically significant differences in the soil, water, and vegetation characteristics. Soil organic carbon (SOC) content, which we use as a proxy for carbon storage, is negatively correlated to dissolved oxygen, pH, and soil water temperature. In addition, Non-Metric Multidimensional Scaling analysis shows a positive relation between plant community composition, SOC content, and water electric conductivity. Our results suggest a three-way interaction between hydrological, soil, and vegetation characteristics in the natural bofedal, which also holds for the artificial bofedal. Vegetation cover of two of the most highly nutritious species for alpaca, Lachemilla diplophylla and Lilaeopsis macloviana with 19-22% of crude protein, are weakly or not correlated to environmental variables, suggesting grazing might be obscuring these potential relationships. Given the high economic importance of alpaca breeding for local communities, expanding bofedales artificially appears an effective strategy to enhance their ecosystem services with minimal impact on the ecohydrological properties of bofedales

Molecular phylogeny of the subfamily Stevardiinae Gill, 1858 (Characiformes: Characidae): classification and the evolution of reproductive traits

Abstract Background The subfamily Stevardiinae is a diverse and widely distributed clade of freshwater fishes from South and Central America, commonly known as “tetras” (Characidae). The group was named “clade A” when first proposed as a monophyletic unit of Characidae and later designated as a subfamily. Stevardiinae includes 48 genera and around 310 valid species with many species presenting inseminating reproductive strategy. No global hypothesis of relationships is available for this group and currently many genera are listed as incertae sedis or are suspected to be non-monophyletic. Results We present a molecular phylogeny with the largest number of stevardiine species analyzed so far, including 355 samples representing 153 putative species distributed in 32 genera, to test the group’s monophyly and internal relationships. The phylogeny was inferred using DNA sequence data from seven gene fragments (mtDNA: 12S, 16S and COI; nuclear: RAG1, RAG2, MYH6 and PTR). The results support the Stevardiinae as a monophyletic group and a detailed hypothesis of the internal relationships for this subfamily. Conclusions A revised classification based on the molecular phylogeny is proposed that includes seven tribes and also defines monophyletic genera, including a resurrected genus Eretmobrycon, and new definitions for Diapoma, Hemibrycon, Bryconamericus sensu stricto, and Knodus sensu stricto, placing some small genera as junior synonyms. Inseminating species are distributed in several clades suggesting that reproductive strategy is evolutionarily labile in this group of fishes.http://deepblue.lib.umich.edu/bitstream/2027.42/134621/1/12862_2015_Article_403.pd

Monitoring an Alien Invasion: DNA Barcoding and the Identification of Lionfish and Their Prey on Coral Reefs of the Mexican Caribbean

BACKGROUND: In the Mexican Caribbean, the exotic lionfish Pterois volitans has become a species of great concern because of their predatory habits and rapid expansion onto the Mesoamerican coral reef, the second largest continuous reef system in the world. This is the first report of DNA identification of stomach contents of lionfish using the barcode of life reference database (BOLD). METHODOLOGY/PRINCIPAL FINDINGS: We confirm with barcoding that only Pterois volitans is apparently present in the Mexican Caribbean. We analyzed the stomach contents of 157 specimens of P. volitans from various locations in the region. Based on DNA matches in the Barcode of Life Database (BOLD) and GenBank, we identified fishes from five orders, 14 families, 22 genera and 34 species in the stomach contents. The families with the most species represented were Gobiidae and Apogonidae. Some prey taxa are commercially important species. Seven species were new records for the Mexican Caribbean: Apogon mosavi, Coryphopterus venezuelae, C. thrix, C. tortugae, Lythrypnus minimus, Starksia langi and S. ocellata. DNA matches, as well as the presence of intact lionfish in the stomach contents, indicate some degree of cannibalism, a behavior confirmed in this species by the first time. We obtained 45 distinct crustacean prey sequences, from which only 20 taxa could be identified from the BOLD and GenBank databases. The matches were primarily to Decapoda but only a single taxon could be identified to the species level, Euphausia americana. CONCLUSIONS/SIGNIFICANCE: This technique proved to be an efficient and useful method, especially since prey species could be identified from partially-digested remains. The primary limitation is the lack of comprehensive coverage of potential prey species in the region in the BOLD and GenBank databases, especially among invertebrates

Young and Intermediate-age Distance Indicators

Distance measurements beyond geometrical and semi-geometrical methods, rely mainly on standard candles. As the name suggests, these objects have known luminosities by virtue of their intrinsic proprieties and play a major role in our understanding of modern cosmology. The main caveats associated with standard candles are their absolute calibration, contamination of the sample from other sources and systematic uncertainties. The absolute calibration mainly depends on their chemical composition and age. To understand the impact of these effects on the distance scale, it is essential to develop methods based on different sample of standard candles. Here we review the fundamental properties of young and intermediate-age distance indicators such as Cepheids, Mira variables and Red Clump stars and the recent developments in their application as distance indicators.Comment: Review article, 63 pages (28 figures), Accepted for publication in Space Science Reviews (Chapter 3 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

Consumers’ value co-creation in sharing economy: The role of social support, consumers’ ethical perceptions and relationship quality

The ancient phenomenon of ‘sharing’ has become mainstream, and transformed the traditional consumer behavior due to proliferation of online sharing economy platforms. Millions of people participate in popular sharing economy platforms (SEPs) such as Airbnb and Uber. Although sharing economy research has gained interest, yet a holistic model that explains the formation of consumer value co-creation intentions on such platforms remains absent. The purpose of this study is to develop a model of the antecedents of consumers value co-creation intentions at SEPs and evaluate it empirically. Building on social support theory, relationship quality theory, value co-creation and marketing ethics literature, we propose a theoretical model that explains the formation of consumers’ value co-creation intentions. Empirical data was collected from 342 Generation Y consumers and analyzed using structural equation modeling (SEM). The results reveal that social support influences ethical perceptions, which further influences value co-creation. Ethical perceptions also influence consumers' trust, satisfaction and commitment with the SEP. However, trust and commitment do not influence value co-creation intentions. Our study contributes to the literature on sharing economy by providing a holistic model of the antecedents of consumers’ value co-creation intentions. We also detail theoretical and managerial implications