Evaluation of four different strategies to characterize plasma membrane proteins from banana roots

Plasma membrane proteins constitute a very important class of proteins. They are involved in the transmission of external signals to the interior of the cell and selective transport of water, nutrients and ions across the plasma membrane. However, the study of plasma membrane proteins is challenging because of their poor solubility in aqueous media and low relative abundance. In this work, we evaluated four different strategies for the characterization of plasma membrane proteins from banana roots: (i) the aqueous-polymer two-phase system technique (ATPS) coupled to gelelectrophoresis (gel-based), and (ii) ATPS coupled to LC-MS/MS (gel free), (iii) a microsomal fraction and (iv) a full proteome, both coupled to LC-MS/ MS. Our results show that the gel-based strategy is useful for protein visualization but has major limitations in terms of time reproducibility and efficiency. From the gel-free strategies, the microsomal-based strategy allowed the highest number of plasma membrane proteins to be identified, followed by the full proteome strategy and by the ATPS based strategy. The high yield of plasma membrane proteins provided by the microsomal fraction can be explained by the enrichment of membrane proteins in this fraction and the high throughput of the gel-free approach combined with the usage of a fast high-resolution mass spectrometer for the identification of proteins

Cryopreservation of Byrsonima intermedia embryos followed by room temperature thawing

Byrsonima intermedia is a shrub from the Brazilian Cerrado with medicinal properties. The storage of biological material at ultra-low temperatures (-196°C) is termed cryopreservation and represents a promising technique for preserving plant diversity. Thawing is a crucial step that follows cryopreservation. The aim of this work was to cryopreserve B. intermedia zygotic embryos and subsequently thaw them at room temperature in a solution rich in sucrose. The embryos were decontaminated and desiccated in a laminar airflow hood for 0-4 hours prior to plunging into liquid nitrogen. The embryo moisture content (% MC) during dehydration was assessed. Cryopreserved embryos were thawed in a solution rich in sucrose at room temperature, inoculated in a germination medium and maintained in a growth chamber. After 30 days, the embryo germination was evaluated. No significant differences were observed between the different embryo dehydration times, where they were dehydrated for at least one hour. Embryos with a MC between 34.3 and 20.3% were germinated after cryopreservation. In the absence of dehydration, all embryos died following cryopreservation. We conclude that B. intermedia zygotic embryos can be successfully cryopreserved and thawed at room temperature after at least one hour of dehydration in a laminar airflow bench

Assessment of RNAi-induced silencing in banana (Musa spp.)

In plants, RNA- based gene silencing mediated by small RNAs functions at the transcriptional or post-transcriptional level to negatively regulate target genes, repetitive sequences, viral RNAs and/or transposon elements. Post-transcriptional gene silencing (PTGS) or the RNA interference (RNAi) approach has been achieved in a wide range of plant species for inhibiting the expression of target genes by generating double-stranded RNA (dsRNA). However, to our knowledge, successful RNAi-application to knock-down endogenous genes has not been reported in the important staple food crop banana

Determinants of soil organic matter chemistry in maritime temperate forest ecosystems

While the influence of climate, vegetation, management and abiotic site factors on total carbon budgets and turn-over is intensively assessed, the influences of these ecosystem properties on the chemical complexity of soil organic matter (SOM) remains poorly understood. This study addresses the chemical composition of NaOH-extracted SOM from maritime temperate forest sites in Flanders (Belgium) by pyrolysis-GC/MS. The studied forests were chosen based on dominant tree species (Pinus sylvestris, Fagus sylvatica, Quercus robur and Populus spp.), soil texture and soil-moisture conditions. Differences in extractable-SOM pyrolysis products were correlated to site variables including dominant tree species, management of the woody biomass, site history, soil properties, total carbon stocks and indicators for microbial activity. Despite of a typical high intercorrelation between these site variables, the influence of the dominant tree species is prominent. The extractable-SOM composition is strongly correlated to litter quality and available nutrients. In nutrient-poor forests with low litter quality, the decomposition of relatively recalcitrant compounds (i.e. short and mid-chain alkanes/alkenes and aromatic compounds) appears hampered, causing a relative accumulation of these compounds in the soil. However, if substrate quality is favorable, no accumulations of recalcitrant compounds were observed, not even under high soil-moisture conditions. Former heathland vegetation still had a profound influence on extractable-SOM chemistry of young pine forests after a minimum of 60 year

Stochastic series expansion method for quantum Ising models with arbitrary interactions

A quantum Monte Carlo algorithm for the transverse Ising model with arbitrary short- or long-range interactions is presented. The algorithm is based on sampling the diagonal matrix elements of the power series expansion of the density matrix (stochastic series expansion), and avoids the interaction summations necessary in conventional methods. In the case of long-range interactions, the scaling of the computation time with the system size N is therefore reduced from N^2 to Nln(N). The method is tested on a one-dimensional ferromagnet in a transverse field, with interactions decaying as 1/r^2.Comment: 9 pages, 5 figure

In vitro culture of Annona emarginata: a rootstock for commercial annonaceae species

Annona emarginata is a native fruit tree in the Brazilian Cerrado which, unlike the commercial species, does not present a high fruit quality. On the other hand, it stands out based on its rootstock value. However, there are some problems that hinder the largescale production of Annona emarginata seedlings for use as a rootstock. In order to overcome these difficulties, micropropagation has become a viable alternative for the rapid and efficient propagation of Annona spp, but Annona emarginata micropropagation has not yet been reported. Therefore, the aim of this study was to initiate Annona emarginata in vitro growth. For axillary shoot proliferation, in vitro nodal segments of 0.5 cm were transferred to MS or WPM supplemented with BA at different concentrations. Nodal segments were also cultured on WPM medium with ranging concentrations of different plant growth regulators, aiming for either shoot elongation or rooting. The results showed that the use of 1 µM BA in WPM medium is recommended for in vitro multiplication of Annona emarginata. This is based on the low adventitious shoot formation, combined with a higher number of buds and leaves. The use of GA3 at any concentration tested induced the formation of malformed plants. Root formation could not be stimulated, regardless the duration of auxin treatment

The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al.,2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood.Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc. . . ).In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis overprints the primary environmental signals in Challenger mound, with extensive coral dissolution and the genesis of small-scaled semi-lithified layers in the Ca-rich intervals. The low cementation rates compared to the extensive dissolution patterns can be explained by an open-system diagenetic model. Moreover, Pirlet et al. (2009) emphasizes the occurrence of gypsum and dolomite in another mound system (Mound Perseverance) in Porcupine Seabight, which might be also related with fluid oxidation events in a semi-open diagenetic system. Along the Moroccan margins, fluid seepage and fluxes in pore water transport affect the development of mound structures, enhancing extensive cold-water coral dissolution and precipitation of diagenetic minerals such as dolomite, calcite, pyrite, etc. (Foubert et al., 2008). Recent carbonate mounds provide indeed an excellent opportunity to study early diagenetic processes in carbonate systems without the complications of burial and/or later meteoric diagenesis

Intensification and diversification of banana production systems: key drivers for increased income and food and nutritional security in the Great Lakes region

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