Search results for "Transporter"
showing 10 items of 676 documents
Analisi tecnica di cantieri meccanizzati nelle operazioni di utilizzazioni forestali in Sicilia
2005
The authors describe the results of a research performed in a wood of the Western Sicily, covered with Pinus halepensis Mill. and Cupressus sempervirens L. Felling, delimbing, cross-cutting and extraction of the logs were carried out. The wood obtained was used as firewood. Two different methods of logs extraction were carried out: with transporters and with polyethylene timber chutes. The working time and the labour productivity recorded during each operations are reported. The results show that in the forest utilization performed in Sicily the mean labour productivity per operator is 2.4 t of firewood per day. This value fits well the mean value recorded in Italy (2-3 t of firewood per da…
Enhanced transport through binding cooperativity in a circulating system
1991
Abstract Allosteric cooperativity in a multiphase circulating system is shown to enhance ion transport when long contact times are involved.
Interaction of glutamic-acid-rich proteins with the cGMP signalling pathway in rod photoreceptors.
1999
The assembly of signalling molecules into macromolecular complexes (transducisomes) provides specificity, sensitivity and speed in intracellular signalling pathways. Rod photoreceptors in the eye contain an unusual set of glutamic-acid-rich proteins (GARPs) of unknown function. GARPs exist as two soluble forms, GARP1 and GARP2, and as a large cytoplasmic domain (GARP' part) of the beta-subunit of the cyclic GMP-gated channel. Here we identify GARPs as multivalent proteins that interact with the key players of cGMP signalling, phosphodiesterase and guanylate cyclase, and with a retina-specific ATP-binding cassette transporter (ABCR), through four, short, repetitive sequences. In electron mic…
Monovalent cation conductance in Xenopus laevis oocytes expressing hCAT-3
2005
hCAT-3 (human cationic amino acid transporter type three) was investigated with both the two-electrode voltage clamp method and tracer experiments. Oocytes expressing hCAT-3 displayed less negative membrane potentials and larger voltage-dependent currents than native or water-injected oocytes did. Ion substitution experiments in hCAT-3-expressing oocytes revealed a large conductance for Na + and K + . In the presence of l-Arg, voltage-dependent inward and outward currents were observed. At symmetrical (inside/outside) concentrations of l-Arg, the conductance of the transporter increased monoexponentially with the l-Arg concentrations; the calculated Vmax and KM values amounted to 8.3 AS and…
Exercise and lactate production:implication in fatigue and in brain signaling
2016
More than two hundred years after its discovery, lactate still remains an intriguing molecule. Considered for a long time as a waste product of metabolism and the culprit behind muscular fatigue, it was then recognized as an important fuel for many cells. In particular, in the nervous system, it has been proposed that lactate, released by astrocytes in response to neuronal activation, is taken up by neurons, oxidized to pyruvate and used for synthesizing acetyl-CoA to be used for the tricarboxylic acid cycle. More recently, in addition to this metabolic role, the discovery of a specific receptor prompted a reconsideration of its role, and lactate is now seen as a sort of hormone, even invol…
Metabolism via arginase or nitric oxide synthase: two competing arginine pathways in macrophages
2014
Macrophages play a major role in the immune system, both as antimicrobial effector cells and as immunoregulatory cells, which induce, suppress or modulate adaptive immune responses. These key aspects of macrophage biology are fundamentally driven by the phenotype of macrophage arginine metabolism that is prevalent in an evolving or ongoing immune response. M1 macrophages express the enzyme nitric oxide synthase (NOS), which metabolizes arginine to nitric oxide (NO) and citrulline. NO can be metabolized to further downstream reactive nitrogen species, while citrulline might be reused for efficient NO synthesis via the citrulline-NO cycle. M2 macrophages are characterized by expression of the…
Inhibition of Saccharomyces cerevisiae Pdr5p by a natural compound extracted from Brazilian Red Propolis
2011
Multidrug resistance of cancer cells and pathogenic microorganisms leading to the treatment failure of some forms of cancer or life-threatening bacterial or fungal infections is often caused by the overexpression of multidrug efflux pumps belonging to the ATP-binding cassette transporters superfamily. The multidrug resistance of fungal cells often involves the overexpression of efflux pumps belonging to the pleiotropic drug resistance (PDR) family of ABC transporters. Possibly the best-studied fungal PDR transporter is the multidrug resistance transporter Pdr5p of Saccharomyces cerevisiae. Some research groups have been searching for new inhibitors of these efflux pumps in order to alleviat…
Blue-copper binding proteins of Medicago truncatula: Characterization of the expression of two genes related to the arbuscular mycorrhizal symbiosis
2009
International audience; Expression profiling of two paralogous arbuscular mycorrhizal (AM)-specific blue copper-binding gene (MtBcpla and MtBcp1b) isoforms was performed by real-time quantitative polymerase chain reaction in wild-type Medicago truncatula Jemalong 5 (J5) during the mycorrhizal development with Glomus intraradices for up to 7 weeks. Timecourse analysis in J5 showed that expression of both MtBcp1 genes increased continuously and correlated strongly with the colonization intensity and arbuscule content. MtPT4, selected as a reference gene of the functional plant-fungus association, showed a weaker correlation to mycorrhizal development. In a second experiment, a range of mycorr…
Changes in gene expression during adaptation of Listeria monocytogenes to the soil environment
2011
project SEST 009; International audience; Listeria monocytogenes is a ubiquitous opportunistic pathogen responsible for listeriosis. In order to study the processes underlying its ability to adapt to the soil environment, whole-genome arrays were used to analyse transcriptome modifications 15 minutes, 30 minutes and 18 h after inoculation of L. monocytogenes EGD-e in soil extracts. Growth was observed within the first day of incubation and large numbers were still detected in soil extract and soil microcosms one year after the start of the experiment. Major transcriptional reprofiling was observed. Nutrient acquisition mechanisms (phosphoenolpyruvate-dependent phosphotransferase systems and…
Separation of atomic and molecular ions by ion mobility with an RF carpet
2021
Gas-filled stopping cells are used at accelerator laboratories for the thermalization of high-energy radioactive ion beams. Common challenges of many stopping cells are a high molecular background of extracted ions and limitations of extraction efficiency due to space-charge effects. At the FRS Ion Catcher at GSI, a new technique for removal of ionized molecules prior to their extraction out of the stopping cell has been developed. This technique utilizes the RF carpet for the separation of atomic ions from molecular contaminant ions through their difference in ion mobility. Results from the successful implementation and test during an experiment with a 600~MeV/u $^{124}$Xe primary beam are…