ion pump
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2021 ◽  
Vol 6 (2) ◽  
pp. 253-264
Author(s):  
Amelia Lestari ◽  
Elsa Lisanti ◽  
Rizhal Hendi Ristanto

This study aimed to develop guided discovery learning-based android learning media to improve critical thinking skills. The developed biology learning media was applied to the nervous system material. The discussion of the physiology of the nervous system is one of the difficult biological materials to understand because it includes the organization and structure of neurons and their functions, ion pump mechanisms when neurons are at rest, action potential mechanisms, mechanisms for neurons to communicate with other cells in the synapses, and organization of the nervous system. This study used research and development (RD) with a method developed by Thiagarajan, namely the 4D model with stages: define, design, develop and disseminate. The stages of this study are limited to the development stage. The results showed that the media was feasible with media, language, and a material expert validation of   3.5, 3.8, and 3.3, respectively.


2021 ◽  
Author(s):  
Alla Shatrova ◽  
Natalja Pugovkina ◽  
Alisa Domnina ◽  
Nikolaj Nikolsky ◽  
Irina Marakhova

Abstract Monovalent ions are involved in growth, proliferation, differentiation of cells as well as in their death. This work concerns the ion homeostasis during senescence induction in human mesenchymal endometrium stem cells (hMESC): hMESCs subjected to oxidative stress (pulse H2O2 treatment) enter the premature senescence accompanied by persistent DNA damage, irreversible cell cycle arrest, cell hypertrophy, lipofuscin accumulation, enhanced β-galactosidase activity. Using flame photometry to estimate K+, Na+ content and Rb+ (K+) fluxes we found that during the senescence development in stress-induced hMESCs, Na+/K+pump-mediated K+ fluxes are enhanced due to the increased Na+ content in senescent cells, while ouabain-resistant K+ fluxes remain unchanged. Senescence progression is accompanied by a peculiar decrease in the K+ content in cells from 800-900 µmol/g to 500-600 µmol/g. Since cardiac glycosides are offered as selective agents for eliminating senescent cells, we investigated the effect of ouabain on ion homeostasis and viability of hMESCs and found that in both proliferating and senescent hMESCs, ouabain (1 nM-1 µM, 24-48 h) inhibited pump-mediated K+ transport (ID50 5x10-8 M), decreased cell K+/Na+ ratio to 0,1-0,2, however did not induce apoptosis. Comparison of the effect of ouabain on hMESCs with the literature data on the selective cytotoxic effect of cardiac glycosides on senescent or cancer cells suggests the ion pump blockade and intracellular K+ depletion should be synergized with target apoptotic signal to induce the cell death.


2021 ◽  
Author(s):  
Kyle Tucker ◽  
Savitha Sridharan ◽  
Hillel Adesnik ◽  
Stephen G Brohawn

Microbial channelrhodopsins are light-gated ion channels widely used for optogenetic manipulation of neuronal activity. ChRmine is a bacteriorhodopsin-like cation channelrhodopsin (BCCR) more closely related to ion pump rhodopsins than other channelrhodopsins. ChRmine displays unique properties favorable for optogenetics including high light sensitivity, a red-shifted activation spectrum, cation selectivity, and large photocurrents while its slow closing kinetics impede some applications. The structural basis for ChRmine function, or that of any other BCCR, is unknown. Here, we present cryo-EM structures of ChRmine in lipid nanodiscs in apo (opsin) and retinal-bound (rhodopsin) forms. The structures reveal an unprecedented trimeric architecture with a lipid filled central pore. Large electronegative cavities on either side of the membrane facilitate high conductance and selectivity for cations over protons. The retinal binding pocket structure suggests spectral and kinetic properties could be tuned with mutations and we identify ChRmine variants with two-fold increased and ten-fold decreased closing rates. These results provide insight into structural features that generate an ultra-potent microbial opsin and provide a platform for rational engineering of channelrhodopsins with improved properties that could expand the scale, depth, and precision of optogenetic manipulations.


2021 ◽  
Vol 511 ◽  
pp. 230427
Author(s):  
Jili Li ◽  
Junwei Zhao ◽  
Chunjuan Tang ◽  
Tiekun Jia ◽  
Jianhua Hou ◽  
...  

2021 ◽  
Vol 204 ◽  
pp. 114133
Author(s):  
Jili Li ◽  
Tiekun Jia ◽  
Chunjuan Tang ◽  
Dongsheng Yu ◽  
Jie Sun ◽  
...  
Keyword(s):  
Ion Pump ◽  

2021 ◽  
Author(s):  
Kaichi Watanabe ◽  
Yuhei Yasui ◽  
Yuta Kurose ◽  
Masashi Fujii ◽  
Takashi Yamamoto ◽  
...  

Abstract Gastrulation is a universal process in the morphogenesis of many animal embryos. In sea urchin embryos, it involves the invagination of a single-layered vegetal plate into the blastocoel. Although morphological and molecular events in gastrulation have been well studied, the mechanical driving forces and the regulatory mechanism underlying gastrulation is not fully understood. In this study, structural features and cytoskeletal distributions were studied in sea urchin embryos using an “exogastrulation” model induced by inhibiting the H+/K+ ion pump with omeprazole. The vegetal poles of the exogastrulating embryos showed reduced roundness indices, intracellular pH polarization, and intracellular F-actin polarization at the pre-early gastrulation stage compared with normal embryos. Gastrulation stopped when F-actin polymerization or degradation was inhibited via RhoA or YAP1 knockout, although pH distributions were independent of such a knockout. A mathematical model of sea urchin embryos at the early gastrulation reproduced the shapes of both normal and exogastrulating embryos using cell-dependent cytoskeletal features based on F-actin and pH distributions. Thus, gastrulation required appropriate cell position-dependent intracellular F-actin distributions regulated by the H+/K+ ion pump through pH control.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257167
Author(s):  
Pattawong Pansodtee ◽  
John Selberg ◽  
Manping Jia ◽  
Mohammad Jafari ◽  
Harika Dechiraju ◽  
...  

A potentiostat is an essential piece of analytical equipment for studying electrochemical devices and reactions. As the design of electrochemical devices evolve, applications for systems with multiple working electrodes have become more common. These applications drive a need for low-cost multi-channel potentiostat systems. We have developed a portable, low-cost and scalable system with a modular design that can support 8 to 64 channels at a cost as low as $8 per channel. This design can replace the functionality of commercial potentiostats which cost upwards of $10k for certain applications. Each channel in the multi-channel potentiostat has an independent adjustable voltage source with a built-in ammeter and switch, making the device flexible for various configurations. The multi-channel potentiostat is designed for low current applications (nA range), but its purpose can change by varying its shunt resistor value. The system can either function as a standalone device or remotely controlled. We demonstrate the functionality of this system for the control of a 24-channel bioelectronic ion pump for open- and closed- loop control of pH.


2021 ◽  
Author(s):  
Kaichi Watanabe ◽  
Yuhei Yasui ◽  
Yuta Kurose ◽  
Masashi Fujii ◽  
Takashi Yamamoto ◽  
...  

Gastrulation is a universal process in the morphogenesis of many animal embryos. In sea urchin embryos, it involves the invagination of single-layered vegetal plate into blastocoel. Although morphological and molecular events have been well studied for gastrulation, the mechanical driving forces and their regulatory mechanism underlying the gastrulation is not fully understood. In this study, structural features and cytoskeletal distributions were studied in sea urchin embryo using an "exogastrulation" model induced by inhibiting the H+/K+ ion pump with omeprazole. The vegetal pole sides of the exogastrulating embryos had reduced roundness indices, intracellular pH polarization, and intracellular F-actin polarization at the pre-early gastrulation compared with the normal embryo. Gastrulation stopped when F-actin polymerization or degradation was inhibited by RhoA or YAP1 knockout, although pH distributions were independent of such a knockout. A mathematical model of sea urchin embryos at the early gastrulation reproduced the shapes of both normal and exogastrulating embryos using cell-dependent cytoskeletal features based on F-actin and pH distributions. Thus, gastrulation required appropriate cell position-dependent intracellular F-actin distributions regulated by the H+/K+ ion pump through pH control.


2021 ◽  
Author(s):  
Koichiro E. Kishi ◽  
Yoon Seok Kim ◽  
Masahiro Fukuda ◽  
Tsukasa Kusakizako ◽  
Elina Thadhani ◽  
...  

ChRmine, a recently-discovered bacteriorhodopsin-like cation-conducting channelrhodopsin, exhibits puzzling properties (unusually-large photocurrents, exceptional red-shift in action spectrum, and extreme light-sensitivity) that have opened up new opportunities in optogenetics. ChRmine and its homologs function as light-gated ion channels, but by primary sequence more closely resemble ion pump rhodopsins; the molecular mechanisms for passive channel conduction in this family of proteins, as well as the unusual properties of ChRmine itself, have remained mysterious. Here we present the cryo-electron microscopy structure of ChRmine at 2.0 Å resolution. The structure reveals striking architectural features never seen before in channelrhodopsins including trimeric assembly, a short transmembrane-helix 3 unwound in the middle of the membrane, a prominently-twisting extracellular-loop 1, remarkably-large intracellular cavities and extracellular vestibule, and an unprecedented hydrophilic pore that extends through the center of the trimer, separate from the three individual monomer pores. Electrophysiological, spectroscopic, and computational analyses provide insight into conduction and gating of light-gated channels with these distinct design features, and point the way toward structure-guided creation of novel channelrhodopsins for optogenetic applications in biology.


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