Search results for "TRANSPORT"
showing 10 items of 4457 documents
Plasma membrane protein trafficking in plant-microbe interactions: a plant cell point of view
2014
International audience; In order to ensure their physiological and cellular functions, plasma membrane (PM) proteins must be properly conveyed from their site of synthesis, i.e., the endoplasmic reticulum, to their final destination, the PM, through the secretory pathway. PM protein homeostasis also relies on recycling and/or degradation, two processes that are initiated by endocytosis. Vesicular membrane trafficking events to and from the PM have been shown to be altered when plant cells are exposed to mutualistic or pathogenic microbes. In this review, we will describe the fine-tune regulation of such alterations, and their consequence in PM protein activity. We will consider the formatio…
The Plant Inorganic Pyrophosphatase Does Not Transport K+ in Vacuole Membrane Vesicles Multilabeled with Fluorescent Probes for H+, K+, and Membrane …
1995
Abstract It has been claimed that the inorganic pyrophosphatase (PPase) of the plant vacuolar membrane transports K+ in addition to H+ in intact vacuoles (Davies, J. M., Poole, R. J., Rea, P. A., and Sanders, D.(1992) Proc. Natl. Acad. Sci. U. S. A. 89, 11701-11705). Since this was not confirmed using the purified and reconstituted PPase consisting of a 75-kDa polypeptide (Sato, M. H., Kasahara, M., Ishii, N., Homareda, H., Matsui, H., and Yoshida, M. (1994) J. Biol. Chem. 269, 6725-6728), these authors proposed that K+ transport by the PPase is dependent on its association with other membrane components lost during purification. We have examined the hypothesis of K+ translocation by the PP…
Nitric oxide contributes to cadmium toxicity in Arabidopsis by promoting cadmium accumulation in roots and by up-regulating genes related to iron upt…
2009
Abstract Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd2+), a nonessential and toxic metal. We demonstrate that Cd2+ induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors, does not involve nitrate reductase and AtNOA1 but requires IRT1, encoding a major plasma membrane transporter for iron but also Cd2+. By analyzing the incidence of NO scavenging or inhibition …
From habitat use to social behavior: natural history of a voiceless poison frog, Dendrobates tinctorius
2019
AbstractDescriptive studies of natural history have always been a source of knowledge on which experimental work and scientific progress rely. Poison frogs are a well-studied group of small Neotropical frogs with diverse parental behaviors, distinct calls, and bright colors that warn predators about their toxicity; and a showcase of advances in fundamental biology through natural history observations. The dyeing poison frog, Dendrobates tinctorius, is emblematic of the Guianas region, widespread in the pet-trade, and increasingly popular in research. This species shows several unusual behaviors, such as the lack of advertisement calls and the aggregation around tree-fall gaps, which remain …
Settlement dynamics and recruitment responses of Mediterranean gorgonians larvae to different crustose coralline algae species
2020
International audience; Sessile marine species such as Anthozoans act as ecosystem engineers due to their three-dimensional structure. Gorgonians, in particular, can form dense underwater forests that give shelter to other species increasing local biodiversity. In the last decades, several Mediterranean gorgonian populations have been affected by natural and anthropogenic impacts which drastically reduced their size. However, some species showed unexpected resilience, mainly due to the supply of new individuals. To understand the mechanisms underlying recovery processes, studies on the first life history stages (i.e. larval dispersal, settlement and recruitment) are needed. In tropical cora…
Rocking of rigid block on nonlinear flexible foundation
2017
Abstract The two prime models used currently to describe rocking of rigid bodies, the Housner’s model and the Winkler foundation model, can capture some of the salient features of the physics of this important problem. These two models involve either null or linear interaction between the block and the foundation. Hopefully, some additional aspects of the problem can be captured by an enhanced nonlinear model for the base-foundation interaction. In this regard, what it is adopted in this paper is the Hunt and Crossley’s nonlinear impact force model in which the impact/contact force is represented by springs in parallel with nonlinear dampers. In this regard, a proper mathematical formulatio…
Communication cost of channel estimation interpolation for group-based vehicular communications in cellular networks
2020
Las comunicaciones inalámbricas para aplicaciones vehiculares en sistemas celulares de quinta generación (5G) deben ser de baja latencia y alta fiabilidad. Entre otros factores, la cantidad de información de control que debe intercambiarse entre cada vehículo y la estación base puede penalizar la latencia de la comunicación. Varios casos de uso vehicular 5G implican comunicaciones dentro de grupos de vehículos, por ejemplo el pelotón de vehículos. Este trabajo se centra en explotar la estructura y características de este servicio vehicular particular basado en grupos para disminuir el intercambio de información de control relacionado con la etapa de estimación del canal necesaria para las c…
Considerations on the optimization of natural gas deliveries by using automated control systems
2019
The current paper aims at optimizing the natural gas deliveries from an underground storage by implementing automated control systems and fiscal measurement systems according to the harmonized European legislation in the area of metrology. In the first part, the authors have carried out an analysis regarding the state of the art at international level with regard to technical solutions for optimizing the deliveries of natural gas by means of a constriction element of a measurement panel. In the following, a software application was created for monitoring the parameters taken from the process gas chromatograph and transferring them to the flow computer by implementing software filters. The n…
Analysis of Possible Concept Solutions of Chain Drives
2019
Possible concept solutions of chain drives are analysed in this paper in order to point out the benefits of chain drive application and, in particular, the possibility of application of multi-level chain drive. The paper also analyses the possibility of replacing the gear drives with chain drives, which, in the case of short-term drive and using the same direction of rotation, enables a slightly simpler drive solution. The paper doesn’t consider difference between the roller and gear chains application because these two types of chains can be used very successfully. Also, the possibility of using timing belt drive is not considered, but it can be also used very successfully in this type of …
Determining efficiency of cycloid reducers using different calculation methods
2019
Cycloid reducers are gear trains which can be classified as planetary transmissions. These transmissions have a very wide range of uses in industry in transporters, robots, satellites, etc. This research presents a comparative analysis of three analytical methods for determining cycloid drive efficiency. The paper explores every mathematically formulated method and compares them to experimental results from literature. The presented methods for determining efficiency have a common property, in that they all determine losses due to friction on the bearing cam surface of the shaft, the rollers of the central gear and the output rollers. The calculation of efficiency values is done for standar…