Protocol : a method to study the direct reprogramming of lateral root primordia to fertile shoots

Background: Plants have the remarkable property to elaborate entire body plan from any tissue part. The conversion of lateral root primordium (LRP) to shoot is an ideal method for plant propagation and for plant researchers to understand the mechanism underlying trans-differentiation. Until now, however, a robust method that allows the efficient conversion of LRP to shoot is lacking. This has limited our ability to study the dynamic phases of reprogramming at cellular and molecular levels. Results: Here we present an efficient protocol for the direct conversion of LRP to a complete fertile shoot system. This protocol can be readily applied to the various ecotypes of Arabidopsis. We show that, the conversion process is highly responsive to developmental stages of LRP and changes in external environmental stimuli such as temperature. The entire conversion process can be adequately analyzed by histological and imaging techniques. As a demonstration, using a battery of cell fate specific markers, we show that confocal time-lapse imaging can be employed to uncover the early molecular events, intermediate developmental phases and relative abundance of stem cell regulators during the conversion of LRP to shoot. Conclusion: Our method is highly efficient, independent of genotypes tested and suitable to study the reprogramming of LRP to shoot in intact plants as well as in excised roots.Peer reviewe

A coherent feed-forward loop drives vascular regeneration in damaged aerial organs of plants growing in a normal developmental context

Aerial organs of plants, being highly prone to local injuries, require tissue restoration to ensure their survival. However, knowledge of the underlying mechanism is sparse. In this study, we mimicked natural injuries in growing leaves and stems to study the reunion between mechanically disconnected tissues. We show that PLETHORA (PLT) and AINTEGUMENTA (ANT) genes, which encode stem cell-promoting factors, are activated and contribute to vascular regeneration in response to these injuries. PLT proteins bind to and activate the CUC2 promoter. PLT proteins and CUC2 regulate the transcription of the local auxin biosynthesis gene YUC4 in a coherent feed-forward loop, and this process is necessary to drive vascular regeneration. In the absence of this PLT-mediated regeneration response, leaf ground tissue cells can neither acquire the early vascular identity marker ATHB8, nor properly polarise auxin transporters to specify new venation paths. The PLT-CUC2 module is required for vascular regeneration, but is dispensable for midvein formation in leaves. We reveal the mechanisms of vascular regeneration in plants and distinguish between the wound-repair ability of the tissue and its formation during normal development.Peer reviewe

Amyloid precursor-like protein 2 (APLP2) affects the actin cytoskeleton and increases pancreatic cancer growth and metastasis.

Amyloid precursor-like protein 2 (APLP2) is aberrantly expressed in pancreatic cancer. Here we showed that APLP2 is increased in pancreatic cancer metastases, particularly in metastatic lesions found in the diaphragm and intestine. Examination of matched human primary tumor-liver metastasis pairs showed that 38.1% of the patients had positive APLP2 expression in both the primary tumor and the corresponding liver metastasis. Stable knock-down of APLP2 expression (with inducible shRNA) in pancreatic cancer cells reduced the ability of these cells to migrate and invade. Loss of APLP2 decreased cortical actin and increased intracellular actin filaments in pancreatic cancer cells. Down-regulation of APLP2 decreased the weight and metastasis of orthotopically transplanted pancreatic tumors in nude mice

Guest dependent Brillouin and Raman scattering studies of Zeolitic Imidazolate Framework-8 (ZIF-8) under external pressure

We have investigated the pressure dependence of the acoustic modes of Zeolitic Imidazolate Framework (ZIF-8) in different pressure transmitting mediums and also under non-hydrostatic conditions using high pressureBrillouin spectroscopy. Our study shows the pressure induced flexibility and dynamics of ZIF-8 framework as well as a huge increase in the acoustic velocities on applying external pressure, illustrating the role of guest in enhancing the elastic properties of the framework. In fact, the elastic constant C₁₁ of the guest incorporated ZIF-8 increases by ∼183% on applying a pressure of only 1.47 GPa. The pressure transmitting medium also plays an important role in controlling the gate opening behaviour of ZIF-8. Pressure dependent Raman study shows significant changes in the modes of ZIF-8 as well as that of that of the pressuretransmitting medium which is entrapped within the framework, indicating that the interaction between the framework and guest is responsible for the medium dependent changes observed in the Brillouinspectra

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Not AvailableInterest in hydrogen energy has gained momentum in recent years as a sustainable and renewable alternative to the fast-depleting fossil fuels. It also provides an additional benefit of not emitting any greenhouse gases (GHG) which provides an incentive to adopt this clean fuel to all countries struggling to meet the GHG limitations as per the Paris agreement to combat climate change. Agricultural residues or second-generation feedstocks or lignocellulosic biomass are possible alternate feedstocks for energy production as they are abundant, cheap resources whose use adds little or no net greenhouse gas to the environment. Over the decades, several technologies have been developed and modified to produce hydrogen economically and sustainably from biomass. However, production from biomass, especially lignocellulosic biomass, has not kept pace with other developments in the field and still suffers from low production rates and yields. Ongoing research is expected to find a solution to the problems faced in this sector, and biohydrogen will emerge as an economical fuel in the future.Not Availabl

Brillouin Light Scattering Study of Microscopic Structure and Dynamics in Pyrrolidinium Based Ionic Liquids

Pyrrolidinium based ionic liquids are known to be good ionic conductors even in solid-state around room temperature, which is attributed to the highly disordered plastic crystalline phase. Moreover, these ionic liquids are characterized by multiple phase transitions which include plastic, structural glass, and glassy crystal phases with varying levels of molecular disorder. Temperature-dependent Brillouin light scattering is used to investigate the phase transitions in a series of alkylmethylpyrrolidinium Bis(trifluoromethanesulfonyl) imides (P1nTFSI, n=1,2,4). Brillouin spectral features such as the number of acoustic modes, their shape, and linewidth provide the picture of different disordered phases resultant of dynamics at the microscopic scale. The longitudinal and transverse acoustic velocities in different phases are determined from the corresponding acoustic mode frequencies (Brillouin shift). Extremely low acoustic velocities in the solid phase of P11TFSI and P12TFSI are a consequence of a high degree of disorder and plasticity present in the system. Anomalous temperature-dependent behavior of linewidth and asymmetric (Fano) line shape of acoustic modes observed in certain phases of P1nTFSI could be due to the strong coupling between the Brillouin central peak and the acoustic phonons. The present results establish that the Brillouin light scattering technique can be efficiently used to understand the complex phase behavior, microscopic structure, and dynamics of ionic liquids.</p

Low cost, rapid synthesis of graphene on Ni: an efficient barrier for corrosion and thermal oxidation

Graphene because of its inert and impermeable nature holds a great promise as a protective coating against corrosion and oxidation. It is envisioned that graphene coated metals will be increasingly used in metal and electronic industries. To date, mainly expensive chemical vapor deposition methods are being employed for its synthesis over large area involving hydrogen at high reaction temperatures. Here we report, a simple and rapid method of Joule heating a Ni foil coated with naphthalene in rotary vacuum to produce graphene without hydrogen gas. The graphene thus grown protects the Ni surface against corrosion and oxidation even at elevated temperatures. This synthetic approach has a great potential for widespread use as it is low cost and adaptable to metal surfaces of complex curvatures

Non-trivial network driven modifications of ion transport in an ionic liquid confined inside a polymer system

We discuss here the polymer specificities which completely govern in a non-trivial manner the effective ion transport in polymer gel electrolytes, an important class of soft matter electrolytes. Confinement of a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)–pyrrolidinium-cation based ionic liquid solution inside a polymer physical network composed of two different polymers with different functionalities is achieved. A physical network of two polymers with different functional groups, viz., one with acrylate and another with acrylonitrile (PAN) leads to multiple interesting consequences. Due to chemical differences between the acrylate-based polymer (formed from (3-trimethoxysilyl)propyl methacrylate (MSMA) monomers) and PAN, the physical knots in the PAN network unlock, leading to a decrease in the elastic modulus with improved mechanical compliance and chain flexibility in the gel. Additionally, ion–polymer interactions increase, resulting in higher free charge carrier density in the gel compared to the unconfined ionic liquid solution. Thus, ion transport is no longer assisted by the ionic liquid and polymer relaxations, as it would be in conventional polymer electrolytes, but fully driven by the chemical characteristics of the polymer physical network. Notably, the polymer matrix significantly influences the anion mobility and transference number. Contrary to the unconfined ionic liquid electrolyte where cations (predominantly due to the pyrrolidinium cation) and anions contribute to the ionic conductivity, the ionic conductivity in PN gels is predominantly due to anions. The gel ionic conductivity is nearly half an order of magnitude higher than that of the unconfined ionic liquid electrolyte and displays good dimensional stability and electrochemical performance in a separator-free battery configuration. Most importantly, this work may revitalize research on single-ion conductors and stimulate new and simple chemical designs of polymer electrolytes displaying high single-ion conductivity

Substrate induced tuning of compressive strain and phonon modes in large area MoS2 and WS2 van der Waals epitaxial thin films

Large area MoS2 and WS2 van der Waals epitaxial thin films with control over number of layers including monolayer is grown by pulsed laser deposition utilizing slower growth kinetics. The films grown on c-plane sapphire show stiffening of A(1g) and E-2g(1) phonon modes with decreasing number of layers for both MoS2 and WS2. The observed stiffening translate into the compressive strain of 0.52% & 0.53% with accompanying increase in fundamental direct band gap to 1.74 and 1.68 eV for monolayer MoS2 and WS2, respectively. The strain decays with the number of layers. HRTEM imaging directly reveals the nature of atomic registry of van der Waals layers with the substrate and the associated compressive strain. The results demonstrate a practical route to stabilize and engineer strain for this class of material over large area device fabrication. (C) 2017 Elsevier B.V. All rights reserved