Proton-coupled monocarboxylate transporters (MCTs) are carriers of high-energy metabolites such as lactate, pyruvate, and ketone bodies and are expressed in most tissues. It has previously been shown that transport activity of MCT1 and MCT4 is enhanced by the cytosolic carbonic anhydrase II (CAII) independent of its catalytic activity. We have now studied the influence of the extracellular, membrane-bound CAIV on transport activity of MCT1/4, heterologously expressed in Xenopus oocytes. Coexpression of CAIV with MCT1 and MCT4 resulted in a significant increase in MCT transport activity, even in the nominal absence of CO2/HCO3(-). CAIV-mediated augmentation of MCT activity was independent of the CAIV catalytic function, since application of the CA-inhibitor ethoxyzolamide or coexpression of the catalytically inactive mutant CAIV-V165Y did not suppress CAIV-mediated augmentation of MCT transport activity. The interaction required CAIV at the extracellular surface, since injection of CAIV protein into the oocyte cytosol did not augment MCT transport function. The effects of cytosolic CAII (injected as protein) and extracellular CAIV (expressed) on MCT transport activity, were additive. Our results suggest that intra- and extracellular carbonic anhydrases can work in concert to ensure rapid shuttling of metabolites across the cell membrane.
Background: Hemorrhagic shock (HS) corresponds to absolute hypovolemia creating an imbalance between oxygen supply and consumption. This causes an impaired hemostasis, a systemic inflammatory response, and microvascular permeability which can lead to multiple organ failure (MOF). There is no specific treatment for the endothelial dysfunction that plays a major role in the evolution towards MOF.
Objective: To explore the possible mechanism of absorption of iron oxide nanoparticles into the human body through the gastrointestinal tract.
Methods: This article used Caco-2 monolayer cells as a cell model, prepared characterized iron oxide nanoparticles(Fe_2O_3 NPs) as suspensions, and intervened in Caco-2 cells. CCK-8 method, transwell method, and atomic spectrophotometer method were used to explore the effect of Fe_2O_3 NPs on the activity of Caco-2 cells and the absorption and transport of them through the Caco-2 monolayer cell model.
Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210000, PR China. Electronic address:
Transport proteins are essential for bacterial resistance to antibiotics and toxins, but their mechanisms remain poorly understood in Bacillus subtilis. In the present study, overexpression of yoeA enhanced resistance to various antibiotics, with its expression induced by these antibiotics, especially penicillin and plipastatin. The ΔyoeA strain exhibited significant growth inhibition at 100 μg/mL of plipastatin, while as high as 10,000 μg/mL of iturin/surfactin are required to achieve comparable inhibition, suggesting a higher sensitivity of ΔyoeA to plipastatin.
Hydrogen sulfide (HS) is an environmental hazard well known for its neurotoxicity. In mammalian cells, HS is predominantly generated by transsulfuration pathway enzymes. In addition, HS produced by gut microbiome significantly contributes to the total sulfide burden in the body.
This study presents the first in vivo measurement of transcytolemmal water exchange in the brain using a novel Magnetic Resonance technique. We extend previous applications of Chemical Exchange Saturation Transfer (CEST) to examine water exchange across cellular membranes in late-stage chicken embryo brains. The immature blood-brain barrier at this stage allows Gadolinium-Based Contrast Agents (GBCAs) to penetrate the brain's interstitial space, sensitizing the CEST effect to water exchange between intra- and extracellular environments.
