Search results for "Transport system"

Human cationic amino acid transporter hCAT-3 is preferentially expressed in peripheral tissues.

2001

At least five distinct carrier proteins form the family of mammalian cationic amino acid transporters (CATs). We have cloned a cDNA containing the complete coding region of human CAT-3. hCAT-3 is glycosylated and localized to the plasma membrane. Transport studies in Xenopus laevis oocytes revealed that hCAT-3 is selective for cationic L-amino acids and exhibits a maximal transport activity similar to other CAT proteins. The apparent substrate affinity and sensitivity to trans-stimulation of hCAT-3 resembles most closely hCAT-2B. This is in contrast to rat and murine CAT-3 proteins that have been reported to display a very low activity and to be inhibited by neutral and anionic L-amino acid…

Between the Megalopolis and the Deep Blue Sky: Challenges of Transport with UAVs in Future Smart Cities

2019

International audience; With the rapid increase of the world's urban population, the infrastructure of the constantly expanding metropolitan areas is undergoing an immense pressure. To meet the growing demands of sustainable urban environments and improve the quality of life for citizens, municipalities will increasingly rely on novel transport solutions. In particular, Unmanned Aerial Vehicles (UAVs) are expected to have a crucial role in the future smart cities thanks to their interesting features such as autonomy, flexibility, mobility, adaptive altitude, and small dimensions. However, densely populated megalopolises of the future are administrated by several municipals, governmental and…

Putative role of cationic amino acid transporter‐3 in murine liver metabolism

2015

Activation of classical protein kinase C decreases transport via systems y+and y+L

2007

Activation of protein kinase C (PKC) downregulates the human cationic amino acid transporters hCAT-1 (SLC7A1) and hCAT-3 (SLC7A3) (Rotmann A, Strand D, Martiné U, Closs EI. J Biol Chem 279: 54185–54192, 2004; Rotmann A, Vekony N, Gassner D, Niegisch G, Strand D, Martine U, Closs EI. Biochem J 395: 117–123, 2006). However, others found that PKC increased arginine transport in various mammalian cell types, suggesting that the expression of different arginine transporters might be responsible for the opposite PKC effects. We thus investigated the consequence of PKC activation by phorbol-12-myristate-13-acetate (PMA) in various human cell lines expressing leucine-insensitive system y+[hCAT-1, h…

Expression, regulation and function of carrier proteins for cationic amino acids.

2001

Different carrier proteins exhibiting distinct transport properties participate in cationic amino acid transport. There are sodium-independent systems, such as b+, y+, y+L and b0,+, and a sodium-dependent system B0,+, most of which have now been identified at the molecular level. In most non-epithelial cells, members of the cationic amino acid transporter (CAT) family mediating system y+ activity seem to be the major entry pathway for cationic amino acids. CAT proteins underlie complex regulation at the transcriptional, post-transcriptional and activity levels. Recent evidence indicates that individual CAT isoforms are necessary for providing the substrate for nitric oxide synthesis, for ex…

Ein schnelles on-line trennsystem unter anwendung von helium-jet- und zentrifugentechnik

1975

Abstract A centrifuge for continuous liquid-liquid phase separation is described. It is designed for rapid solvent extraction of short-lived radioactive isotopes (half-lives in the order of seconds). The centrifuge is characterized by simple construction and operation principle, easy handling, low cost, and a minimum hold-up time of less than five seconds (phase purity 99.0–99.9%). The on-line connection to a helium-jet transport system is described. Problems concerning the transfer of activities into a liquid phase from the helium-jet at atmospheric pressure are discussed.

Plasma membrane transporters for arginine

2004

The supply of arginine may become rate limiting for enzymatic reactions that use this semiessential amino acid as a substrate (e.g., nitric oxide, agmatine, creatine, and urea synthesis), particularly under conditions of high demand such as growth, sepsis, or wound healing. In addition, arginine acts as a signaling molecule that regulates essential cellular functions such as protein synthesis, apoptosis, and growth. In the past decade, a number of carrier proteins for amino acids have been identified on the molecular level. They belong to different gene families, exhibit overlapping but distinctive substrate specificities, and can further be distinguished by their requirement for the cotran…

Tramway Track: A New Approach for Measuring the Transverse Profile of Worn-Out Rails

2012

Abstract Monitoring the wear condition of the tramway superstructure is one of the key points to guarantee an adequate safety level of the light rail transport system. The purpose of this paper is to suggest a new non-conventionalprocedure for measuring the transverse profile of rails in operation by means of image-processing technique. This methodological approach is based on the “information” contained in high-resolution photographic images of tracks and on specific algorithms which allow to obtain the exact geometric profile of the rails and therefore to measure the state of the rail-head extrados wear.

Identification of Cysteine Residues in Human Cationic Amino Acid Transporter hCAT-2A That Are Targets for Inhibition by N-Ethylmaleimide

2013

In most cells, cationic amino acids such as l-arginine, l-lysine, and l-ornithine are transported by cationic (CAT) and y(+)L (y(+)LAT) amino acid transporters. In human erythrocytes, the cysteine-modifying agent N-ethylmaleimide (NEM) has been shown to inhibit system y(+) (most likely CAT-1), but not system y(+)L (Devés, R., Angelo, S., and Chávez, P. (1993) J. Physiol. 468, 753-766). We thus wondered if sensitivity to NEM distinguishes generally all CAT and y(+)LAT isoforms. Transport assays in Xenopus laevis oocytes established that indeed all human CATs (including the low affinity hCAT-2A), but neither y(+)LAT isoform, are inhibited by NEM. hCAT-2A inhibition was not due to reduced tran…

Reaktywacje pasażerskich linii kolejowych w Polsce w latach 2000–2020

2021

Badanie dotyczyło procesów reaktywacji pasażerskiego regionalnego ruchu kolejowego w Polsce w latach 2000– 2020. Po przeprowadzonej przed 2000 r. redukcji sieci kolejowej zidentyfikowana została faza renesansu przewozów pasażerskich. W badanym okresie odtworzono przewozy na 63 odcinkach linii. Łączna długość reaktywowanych tras wynosiła 1992 km, z tego odcinki zelektryfikowane objęły 549 km sieci. Największe obszary koncentracji działań reaktywacyjnych zidentyfikowano w południowo-wschodniej oraz północnej Polsce. Na większości tras średnia prędkość wynosiła 65 km/h. Oferta przewozowa na 55% linii oparta była na więcej niż sześciu połączeniach dziennie. Rozpoznano również zjawisko niekonsek…