The I current is important in the heart's response to sympathetic stimulation. β-adrenergic stimulation increases the amount of I and creates a repolarization reserve that shortens the cardiac action potential duration. We have recently shown that 8-CPT-cAMP, a membrane-permeable cAMP analog, changes the channel kinetics and causes it to open more quickly and more often, as well as to higher subconductance levels, which produces an increase in the I current. The mechanism proposed to underlie these kinetic changes is increased activation of the voltage sensors. The present study extends our previous work and shows detailed subconductance analysis of the effects of 8-CPT-cAMP on an enhanced gating mutant (S209F) and on a double pseudo-phosphorylated I channel (S27D/S92D). 8-CPT-cAMP still produced kinetic changes in S209F + KCNE1, further enhancing gating, while S27D/S92D + KCNE1 showed no significant response to 8-CPT-cAMP, suggesting that these last two mutations fully recapitulate the effect of channel phosphorylation by cAMP.
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http://dx.doi.org/10.1080/19336950.2018.1499369 | DOI Listing |
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January 2025
Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, Jyväskylä, FI-40014, Finland.
Designing cost-effective electrocatalysts with fast reaction kinetics and high stability is an outstanding challenge in green hydrogen generation through overall water splitting (OWS). Layered double hydroxide (LDH) heterostructure materials are promising candidates to catalyze both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), the two OWS half-cell reactions. This work develops a facile hydrothermal route to synthesiz hierarchical heterostructure MoS@NiFeCo-LDH and MoS@NiFeCo-Mo(doped)-LDH electrocatalysts, which exhibit extremely good OER and HER performance as witnessed by their low IR-corrected overpotentials of 156 and 61 mV with at a current density of 10 mA cm under light assistance.
View Article and Find Full Text PDFBr J Hosp Med (Lond)
December 2024
Department of Neurology, Wuhan Brain Hospital, General Hospital of Yangtze River Shipping, Wuhan, Hubei, China.
Arterial spin labelling (ASL) is a non-invasive magnetic resonance imaging (MRI) method. ASL techniques can quantitatively measure cerebral perfusion by fitting a kinetic model to the difference between labelled images (tag images) and ones which are acquired without labelling (control images). ASL functional MRI (fMRI) provides quantitative perfusion maps by using arterial water as an endogenous tracer instead of depending on vascular blood oxygenation level.
View Article and Find Full Text PDFPhotochem Photobiol
January 2025
Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences (IPAC RAS), Chernogolovka, Russia.
Recently (Photochem Photobiol. 2023;100:1277-1289. doi:10.
View Article and Find Full Text PDFFood Technol Biotechnol
December 2024
Department of Food Technology, Faculty of Food Science and Technology, Jalan Universiti 1, 43400, Universiti Putra Malaysia, Selangor, Malaysia.
Research Background: Anthocyanin pigments in mangosteen pericarp can serve as natural colourants; however, their stability is compromised by enzymatic browning caused by polyphenol oxidase (PPO). Thus, this study aims to investigate how hot water and steam blanching affect the PPO activity, phenolic profile and antioxidant properties of mangosteen pericarp.
Experimental Approach: Fresh mangosteen pericarp was blanched in hot water or steam at 100 °C for 0, 30, 60, 90 and 120 s and the residual PPO activity, total phenolic content (TPC), total anthocyanins, antioxidant activity, browning index and colour properties were evaluated.
Unlabelled: Vitamin B (cobalamin) is a high-value yet scarce cofactor required for various metabolic processes, making its efficient handling important for maintaining metabolic homeostasis. While the involvement of ATP:cob(I)alamin adenosyltransferases (MMAB) in the synthesis, delivery, and repair of 5'-deoxyadenosylcobalamin (AdoCbl) is well established, the kinetic mechanisms that regulate this process, particularly its negative cooperativity, remain poorly understood. Understanding these mechanisms is key to clarifying how MMAB efficiently uses AdoCbl, prevents resource wastage, and supports bacterial survival in nutrient-limited environments.
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