Disease relevance of Biological Transport, Active

• D-galactose-binding (or chemoreceptor) protein of Escherichia coli serves as an initial component for both chemotaxis towards galactose and glucose and high-affinity active transport of the two sugars [1].
• In contrast, D-lactate-driven active transport is abolished by the hydrazone and by anoxia or cyanide but not by the carbodiimide [2].
• The TonB-dependent complex of Gram-negative bacteria couples the inner membrane proton motive force to the active transport of iron.siderophore and vitamin B(12) across the outer membrane [3].
• Cupric ion-mediated active transport of amino acids in membrane vesicles of Mycobacterium phlei [4].
• Lactobacillus delbrueckii 7469, however, which specifically requires pyridoxamine-P or pyridoxal-P for growth, accumulates both these compounds and pyridoxine-P from the medium, apparently by active transport, but not pyridoxine, pyridoxamine, or pyridoxal [5].

High impact information on Biological Transport, Active

• This is exemplified by the uptake of phosphate or its close analogue arsenate by bacterial cells by way of a high affinity active transport system dependent on a phosphate-binding protein; this system is unable to recognize other inorganic oxyanions and is, moreover, distinct from the one for sulphate transport [6].
• This detailed structure analysis provides new understanding of protein-sugar interaction, the process by which the binding protein minimizes the difference in the stability of the two bound sugar anomers, and the roles of periplasmic binding proteins in active transport [7].
• Coupled active transport of Na+ and K+ across cellular plasma membranes is mediated by (Na+ + K+)-stimulated Mg2+-dependent ATPase [8].
• FhuA, the receptor for ferrichrome-iron in Escherichia coli, is a member of a family of integral outer membrane proteins, which, together with the energy-transducing protein TonB, mediate the active transport of ferric siderophores across the outer membrane of Gram-negative bacteria [9].
• This cross-bridge cycle is similar to the kinetic cycle that drives active transport and illustrates the general principles of free energy transduction by adenosine triphosphatase systems [10].

Chemical compound and disease context of Biological Transport, Active

• Addition of ubiquinone-1 to E. coli ML 308-225 membrane vesicles dramatically increases coupling between NADH oxidation and active transport such that initial rates and steady-state levels of lactose and amino-acid accumulation are comparable to those observed during D-lactate oxidation [11].
• Vesicles so prepared catalyze active transport of proline and serine in the presence of phosphoenolpyruvate; this activity is abolished by the protonophore carbonyl cyanide-m-chlorophenylhydrazone and by the H+-ATPase inhibitor N,N' dicyclohexylcarbodiimide but not by anoxia or cyanide [2].
• The three-dimensional crystal structure of the L-arabinose-binding protein from E. coli, an essential component in the active transport of L-arabinose, has been solved at 5 A resolution using the method of multiple isomorphous replacement [12].
• Small-angle x-ray scattering and computer modeling have been used to study the effects of ligand binding to the leucine/isoleucine/valine-binding protein, an initial component of the high-affinity active transport system for branched-chain aliphatic amino acids in Escherichia coli [13].
• The reconstitution of binding protein-dependent active transport of glutamine in isolated membrane vesicles from Escherichia coli [14].

Biological context of Biological Transport, Active

• The ntrC protein is able to bind to the regulatory region (dhuA) of an operon coding for genes involved in the active transport of histidine, but not to another transport-related regulatory region, argTr [15].
• Nuclear export of MAP kinase (ERK) involves a MAP kinase kinase (MEK)-dependent active transport mechanism [16].
• We propose that active transport of beta-actin mRNA to regions of cell motility is one possible objective of these signal transduction pathways [17].
• The substrate requirements, kinetics and Cd2+/glutathione stoichiometry of cadmium uptake and the molecular weight of the transport-active complex demonstrate that YCF1 selectively catalyzes the transport of bis(glutathionato)cadmium (Cd x +GS2) [18].
• Individual mutants of both the Tra+ and Tra minus classes exhibited no detectable intracellular accumulation of methyl-beta-D-galactopyranoside; thus, the Tra+ phenotype cannot be explained by the mutants' levels of residual active transport [19].

Anatomical context of Biological Transport, Active

• Although active glucose transport was demonstrable in both jejunum and ileum, it was not possible to demonstrate an ileal mechanism for active transport of taurocholate in the fetus [20].
• Concentration of myo-inositol in skeletal muscle of the rat occurs without active transport [21].
• Prostaglandin E2 (10(-5) M), indomethacin (10(-6) M), piroxicam (5 x 10(-5) M), and mepacrine (10(-4) M) partially inhibited the amebic lysate effect on active transport in the rat descending colon [22].
• These results are consistent with active transport of H+ (or HCO3(-) across alveolar epithelium [23].
• Purified inside-out vesicles from human erythrocytes were used to investigate the active transport of oxidized glutathione (GSSG) [24].

Associations of Biological Transport, Active with chemical compounds

• Therefore, the response to DNP distinguished between inhibition of transport and metabolism; this approach may be useful for the investigation of factors that regulate active transport [25].
• We compared, therefore, the uptake of 42K+ with the decrement in cellular K+ content when active transport was inhibited by ouabain [26].
• In those studies we failed to demonstrated active transport of sodium chloride by the tALH, although it was shown that the isotopic permeability to sodium and chloride was unusually high [27].
• We found that more than 94% of 3-O-methyl-glucose is absorbed by active transport when luminal concentrations range from 50 to 400 mM [28].
• At physiological temperature, however, the scavenger is effective only when glutamate uptake is blocked, revealing a role of active transport in both synaptic and extrasynaptic communication [29].

Gene context of Biological Transport, Active

• Multidrug resistance protein. Identification of regions required for active transport of leukotriene C4 [30].
• MRP1 mediates the active transport of numerous GSH-, sulfate-, and glucuronide-conjugated organic anions and can transport certain xenobiotics by a mechanism that may involve co-transport with GSH [31].
• Lipid-poor apolipoproteins remove cellular cholesterol and phospholipids by an active transport pathway controlled by an ATP binding cassette transporter called ABCA1 (formerly ABC1) [32].
• We found that the primary active transport of estradiol-17-beta-d-glucuronide (E217betaG), a major product of human steroid metabolism, was differently modulated by bile acids and organic anions in the case of human MRP2 and MRP3 [33].
• (Hobson, A. C., Weatherwax, R., and Ames, G.F.-L. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 7333-7337) that the hisP and malK products bind ATP suggests that these four gene products may be involved in coupling the energy from ATP to drive the active transport in their respective transport systems [34].

Analytical, diagnostic and therapeutic context of Biological Transport, Active

• The active transport of GDPmannose as well as the GDPase and another presumed Golgi enzyme, alpha 1,2-mannosyltransferase, are concentrated in a subcellular fraction that can be partially separated, by velocity sucrose gradient centrifugation, from a fraction enriched in an endoplasmic reticulum marker enzyme [35].
• TonB protein functions as an energy transducer, coupling cytoplasmic membrane electrochemical potential to the active transport of vitamin B12 and Fe(III)-siderophore complexes across the outer membrane of Escherichia coli and other Gram-negative bacteria [36].
• Luminal and peritubular perfusion experiments with symmetrical bicarbonate-free solutions that contained only phosphate buffer showed that even under those conditions fluid movement driven by cyanide-sensitive active transport increased with flow rate [37].
• METHODS: The passive and active transport of fluorescein through the BRB was quantitated by vitreous fluorometry [38].
• Duodenal active transport of calcium and phosphate in vitamin D-deficient rats: effects of nephrectomy, Cestrum diurnum, and 1alpha,25-dihydroxyvitamin D3 [39].

References