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Computational Modeling of Transepithelial Endogenous Electric Signals
Published in Ben Greenebaum, Frank Barnes, Biological and Medical Aspects of Electromagnetic Fields, 2018
Somen Baidya, Ahmed M. Hassan, Min Zhao
Cotransport channels are associated with many kinds of epithelial tissues. Cotransport is a process that does not require ATPase activity rather it utilizes the movement of one ion down the concentration gradient to transport other solutes into or out of the cell [47]. Transport of solutes in this case is performed by one protein or by a protein complex. Any cotransport system that allows transportation of two or solutes in the same direction, either inward or outward through the cell membrane is referred as symport [47], whereas two solutes transported through the membrane in the opposite direction (i.e., one going in, the other one going out of the cellular compartment) via a cotransport system is defined as antiport [47]. One example of symport system is the Na+/K+/2Cl− pump located in basolateral membrane which pumps one Na+, one K+, and two Cl− ions from the basolateral compartment to the cellular compartment (all ions in the same direction). The respective cotransport flux can be calculated from Eq. 11.7 as [45]
Physical properties of the body fluids and the cell membrane
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
Figure 3.7 illustrates the passive transport of solutes through the cell membrane by either carrier proteins or channel proteins. Carrier proteins can transport only a single solute across the membrane, a process called uniport, or there can be transport of two different solutes, called coupled transport. The passive transport of glucose into a cell by glucose transporters is an example of a uniport. In coupled transport, the transfer of one solute occurs in combination with the transport of another solute. This coupled transport of the two solutes can occur with both solutes transported in the same direction, symport, or in opposite directions, antiport. An example of coupled transport is the sodium ion gradient–driven symport of glucose and sodium ions.
Cell Biology for Bioprocessing
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
Uniporters transfer a single solute from a high concentration side to a low concentration side, e.g., the GLUT1 transporter for glucose and the GLUT5 transporter for fructose. Symporters and antiporters transfer two solutes simultaneously. A transporter that delivers the two solutes in the same direction is called symporter. Conversely, an antiporter transfers two solutes in opposite directions.
Cultivation of different microalgae with pentose as carbon source and the effects on the carbohydrate content
Published in Environmental Technology, 2019
Bárbara Catarina Bastos de Freitas, Eduarda Holz Brächer, Etiele Greque de Morais, Daniel Ibraim Pires Atala, Michele Greque de Morais, Jorge Alberto Vieira Costa
Because environmental alterations can lead to metabolic and photosynthesis changes that can increase bioproduct formation in microalgae cultures, the possibility of using pentose in crops is an interesting alternative. With the wide availability of lignocellulosic residues, some studies [3–6] have been developed with the objective of evaluating the potential of using pentoses as an alternative source of carbon in the cultivation of microalgae. However, the use of pentoses (C5) in the cultivation of algae is still not widely studied. Recently, the first metabolic pathway for pentose absorption in microalgae was proposed for cells of Chlorella sorokiniana[7], in which the transport of d-Xylose across the cell membrane can be accomplished using an inducible hexose symporter. The results obtained by Zheng et al. [7] showed that the microalgae of the genus Chlorella can not only assimilate d-Xylose from the culture environment but also present the ability to degrade this pentose.
Nuclear Medicine in Oncology
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Carla Oliveira, Rui Parafita, Ana Canudo, Joana Correia Castanheira, Durval C. Costa
The basis of this therapy lies in the fact that iodine is an integral component of triiodothyronine and thyroxine hormones. During the process of biosynthesis for these hormones, iodine is taken up by the follicular cells in the thyroid – thyrocytes – by active transport (through sodium iodide symporter – NIS) and incorporated in the thyroglobulin (process known as organification), being stored in the glandular colloid until thyroid hormone secretion into the blood stream (Filetti et al. 1999).
Non-stomatal limitation of photosynthesis by soil salinity
Published in Critical Reviews in Environmental Science and Technology, 2021
Ting Pan, Minmin Liu, Vladimir D. Kreslavski, Sergey K. Zharmukhamedov, Chenrong Nie, Min Yu, Vladimir V. Kuznetsov, Suleyman I. Allakhverdiev, Sergey Shabala
Plant possess at least three Na+-dependent transport systems: the sodium hydrogen antiporter (NhaD)-type carriers, the Na+/Pi symporter anion transporter (PHT), and the bile acid:sodium symporter family protein (BASS) (Figure 2; Pavón et al., 2008; Furumoto et al., 2011). AtNHD1 catalyzes Na+/H+ antiport across chloroplast envelope, whose transcript level was not up-regulated by NaCl treatment (Müller et al., 2014). atndh1 mutant displayed markedly reduced quantum yield of PSII and increased qN upon salt stress, suggesting AtNHD1 plays an important role in protecting vital chloroplast reactions from toxic high Na+ levels (Müller et al., 2014). NhaD from the facultative halophyte Mesembryanthemum crystalllinum (McNhaD) also mediates Na+ efflux at the chloroplast envelope via Na+/H+ antiport (Cosentino, Fischer-Schliebs, Bertl, Thiel, & Homann, 2010). A quantitative analysis revealed that under high salinity the transcript levels of McNhaD increased in leaves but not in roots, suggesting that chloroplast is one of the compartments involved in the response rapidly of cells to salt stress and McNhaD is required for stromal compartmentation of sodium (Cosentino et al., 2010).The BASS2 functions as a sodium-dependent pyruvate uptake transporter, which localized at the chloroplast envelope membrane (Furumoto et al., 2011). The expression of TaBASS2 was induced by NaCl stress and a constitutive expression of TaBASS2 enhanced salinity tolerance in transgenic wheat and Arabidopsis (Zhao et al., 2016). Furthermore, TaBASS2 positively regulates plant response to salinity stress by repressing ABA INSENSITIVE 4 (ABI4), a node linking ABA signaling and plastid retrograde signaling pathways (Zhao et al., 2016). PHT4;1 and PHT4;4 have been characterized as H+ and Na+ dependent transporters (Guo, Jin, et al., 2008; Miyaji et al., 2015; Młodzińska & Zboińska, 2016; Pavón et al., 2008). The Arabidopsis thylakoid-located phosphate transporter PHT4;1 plays an important role in chloroplast phosphate compartmentation and ATP synthesis (Karlsson et al., 2015). It also maintains the ionic environment of thylakoids, which affects the macro-organization of complexes and induction of photoprotective mechanisms (Karlsson et al., 2015). AtPHT4;4 protein is an ascorbate transporter at the chloroplast envelope membrane, which may be required for tolerance to strong light stress (Miyaji et al., 2015). Ruiz-Lau et al. (2017) presented a comprehensive compilation of genes encoding putative ion transporters and channels expressed in the chloroplasts of the moss Physcomitrella patens based on genomic and RNA-seq analyses, with a particular focus on the Na+ and K+ fluxes. The transcriptomic analysis showed most of the ionic transporters ascribed to chloroplast were repressed by salt stress, including those related to Na+ and K+ (Ruiz-Lau et al., 2017). Similar to AtNHD1, none of the moss NHAD transporters were induced by saline conditions (Ruiz-Lau et al., 2017).