Dependence of the membrane potential on intracellular ATP concentration in tonoplast-free cells of Nitellopsis obtusa

Planta ◽  
1983 ◽  
Vol 157 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Tetsuro Mimura ◽  
Teruo Shimmen ◽  
Masashi Tazawa
Keyword(s):  
Membrane Potential ◽  
Nitellopsis Obtusa ◽  
Intracellular Atp ◽  
Atp Concentration ◽  
Free Cells

Bioenergetic studies of Methanosphaera stadtmanae, an obligate H2–methanol utilising methanogen

1993 ◽  
Vol 39 (8) ◽  
pp. 742-748 ◽  
Author(s):  
Richard Sparling ◽  
Michael Blaut ◽  
Gerhard Gottschalk
Keyword(s):  
Membrane Potential ◽  
Atp Synthesis ◽  
Proton Motive Force ◽  
Rapid Decrease ◽  
Motive Force ◽  
Atpase Inhibitor ◽  
Intracellular Atp ◽  
Atp Concentration ◽  
Methanosphaera Stadtmanae

In Methanosphaera stadtmanae producing methane from the reduction of methanol with H2, sodium (> 0.3 mM Na+) was not required for methanogenesis or ATP synthesis. The ATPase inhibitor N,N′-dicyclohexylcarbodiimide inhibited both ATP synthesis and methanogenesis, but was only effective in the presence of low Na+ (< 1 mM). The observed N,N′ -dicyclohexylcarbodiimide inhibition of methanogenesis was relieved by the addition of the protonophore 3,3′,4′,5-tetrachlorosalicylanilide. 3,3′,4′,5-Tetrachlorosalicylanilide itself caused a rapid decrease in the intracellular ATP concentration and stimulated methanogenesis. This stimulation was enhanced when the cells were incubated in the presence of NaCl. The effects of Na+ on the effectiveness of N,N′-dicyclohexylcarbodiimide and 3,3′,4',5-tetrachlorosalicylanilide cannot yet be explained. Ionophores (3,3′,4′,5-tetrachlorosalicylanilide, SF6847, monensin, and gramicidin) caused decreases in the membrane potential and the intracellular ATP concentration while stimulating methanogenesis. The data presented are consistent with the coupling of the last step of methanogenesis to ATP synthesis via a proton motive force in a representative of the Methanobacteriales.Key words: methanogenesis, proton motive force, membrane potential.

scholarly journals Antibacterial activity and mechanism of sanguinarine against Providencia rettgeri in vitro

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9543
Author(s):  
Qian Zhang ◽  
Yansi Lyu ◽  
Jingkai Huang ◽  
Xiaodong Zhang ◽  
Na Yu ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Crystal Violet ◽  
Membrane Integrity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Crystal Violet Staining ◽  
Providencia Rettgeri ◽  
Intracellular Atp ◽  
Atp Concentration

Background Sanguinarine (SAG), a benzophenanthridine alkaloid, occurs in Papaveraceas, Berberidaceae and Ranunculaceae families. Studies have found that SAG has antioxidant, anti-inflammatory, and antiproliferative activities in several malignancies and that it exhibits robust antibacterial activities. However, information reported on the action of SAG against Providencia rettgeri is limited in the literature. Therefore, the present study aimed to evaluate the antimicrobial and antibiofilm activities of SAG against P. rettgeri in vitro. Methods The agar dilution method was used to determine the minimum inhibitory concentration (MIC) of SAG against P. rettgeri. The intracellular ATP concentration, intracellular pH (pHin), and cell membrane integrity and potential were measured. Confocal laser scanning microscopy (CLSM), field emission scanning electron microscopy (FESEM), and crystal violet staining were used to measure the antibiofilm formation of SAG. Results The MIC of SAG against P. rettgeri was 7.8 μg/mL. SAG inhibited the growth of P. rettgeri and destroyed the integrity of P. rettgeri cell membrane, as reflected mainly through the decreases in the intracellular ATP concentration, pHin and cell membrane potential and significant changes in cellular morphology. The findings of CLSM, FESEM and crystal violet staining indicated that SAG exhibited strong inhibitory effects on the biofilm formation of P. rettgeri and led to the inactivity of biofilm-related P. rettgeri cells.

Antibacterial Mechanism of Vanillic Acid on Physiological, Morphological, and Biofilm Properties of Carbapenem-Resistant Enterobacter hormaechei

2019 ◽  
Vol 83 (4) ◽  
pp. 576-583 ◽  
Author(s):  
WEIDONG QIAN ◽  
MIN YANG ◽  
TING WANG ◽  
ZHAOHUAN SUN ◽  
MIAO LIU ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Natural Products ◽  
Membrane Potential ◽  
Cell Morphology ◽  
Vanillic Acid ◽  
Biofilm Formation ◽  
Diffusion Method ◽  
Intracellular Atp ◽  
Carbapenem Resistant ◽  
Enterobacter Hormaechei

ABSTRACT Many studies have evaluated the antimicrobial activity of natural products against various microorganisms, but to our knowledge there have been no studies of the possible use of natural products for their antimicrobial activity against Enterobacter hormaechei. In this study, we investigated vanillic acid (VA) for its antimicrobial activities and its modes of action against carbapenem-resistant E. hormaechei (CREH). The MIC of VA against CREH was determined by the agar diffusion method. The antibacterial action of VA against CREH was elucidated by measuring variations in intracellular ATP concentration, intracellular pH, membrane potential, and cell morphology. Moreover, the efficacy of VA against biofilm formation and VA damage to CREH cells embedded in biofilms were further explored. Our results show that VA was effective against CREH with a MIC of 0.8 mg/mL. VA could rupture the cell membrane integrity of CREH, as measured by a decrease of intracellular ATP, pH, and membrane potential, along with distinctive alternations in cell morphology. In addition, VA exerted a remarkable inhibitory effect on the biofilm formation of CREH and also killed CREH cells within biofilms. These findings show that VA has a potent antibacterial and antibiofilm activity against CREH and, hence, has the potential to be used clinically as a novel candidate agent to treat CREH infections and in the food industry as a food preservative and surface disinfectant. HIGHLIGHTS

scholarly journals In Vitro Antibacterial Activity and Mechanism of Vanillic Acid against Carbapenem-Resistant Enterobacter cloacae

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 220 ◽  
Author(s):  
Weidong Qian ◽  
Yuting Fu ◽  
Miao Liu ◽  
Ting Wang ◽  
Jianing Zhang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Membrane Potential ◽  
Cell Membrane ◽  
Crystal Violet ◽  
Vanillic Acid ◽  
Membrane Integrity ◽  
Enterobacter Cloacae ◽  
Carbapenem Resistant ◽  
Atp Concentration

Vanillic acid (VA) is a flavoring agent found in edible plants and fruits. Few recent studies exhibited robust antibacterial activity of VA against several pathogen microorganisms. However, little was reported about the effect of VA on carbapenem-resistant Enterobacter cloacae (CREC). The purpose of the current study was to assess in vitro antimicrobial and antibiofilm activities of VA against CREC. Here, minimum inhibitory concentrations (MIC) of VA against CREC was determined via gradient diffusion method. Furthermore, the antibacterial mode of VA against CREC was elucidated by measuring changes in intracellular adenosine triphosphate (ATP) concentration, intracellular pH (pHin), cell membrane potential and membrane integrity. In addition, antibiofilm formation of VA was measured by crystal violet assay and visualized with field emission scanning electron microscopy (FESEM) and confocal laser scanning microscopy (CLSM). The results showed that MIC of VA against E. cloacae was 600 μg/mL. VA was capable of inhibiting the growth of CREC and destroying the cell membrane integrity of CREC, as confirmed by the decrease of intracellular ATP concentration, pHin and membrane potential as well as distinctive variation in cellular morphology. Moreover, crystal violet staining, FESEM and CLSM results indicated that VA displayed robust inhibitory effects on biofilm formation of CREC and inactivated biofilm-related CREC cells. These findings revealed that VA exhibits potent antibacterial activity against CREC, and thus has potential to be exploited as a natural preservative to control the CREC associated infections.

scholarly journals ATP Dependence of the ICl, swell Channel Varies with Rate of Cell Swelling

1999 ◽  
Vol 113 (3) ◽  
pp. 441-456 ◽  
Author(s):  
Tamara Bond ◽  
Srisaila Basavappa ◽  
Michael Christensen ◽  
Kevin Strange
Keyword(s):  
Cell Metabolism ◽  
Neuroblastoma Cells ◽  
Metabolic Inhibitors ◽  
Cell Swelling ◽  
Hyperbolic Function ◽  
Channel Activation ◽  
Atp Production ◽  
Intracellular Atp ◽  
Atp Concentration ◽  
Current Activation

Swelling-induced activation of the outwardly rectifying anion current, ICl, swell, is modulated by intracellular ATP. The mechanisms by which ATP controls channel activation, however, are unknown. Whole cell patch clamp was employed to begin addressing this issue. Endogenous ATP production was inhibited by dialyzing N1E115 neuroblastoma cells for 4–5 min with solutions containing (μM): 40 oligomycin, 5 iodoacetate, and 20 rotenone. The effect of ATP on current activation was observed in the absence of intracellular Mg2+, in cells exposed to extracellular metabolic inhibitors for 25–35 min followed by intracellular dialysis with oligomycin, iodoacetate, and rotenone, after substitution of ATP with the nonhydrolyzable analogue AMP-PNP, and in the presence of AMP-PNP and alkaline phosphatase to dephosphorylate intracellular proteins. These results demonstrate that the ATP dependence of the channel requires ATP binding rather than hydrolysis and/or phosphorylation reactions. When cells were swollen at 15–55%/min in the absence of intracellular ATP, current activation was slow (0.3–0.8 pA/pF per min). ATP concentration increased the rate of current activation up to maximal values of 4–6 pA/pF per min, but had no effect on the sensitivity of the channel to cell swelling. Rate of current activation was a saturable, hyperbolic function of ATP concentration. The EC50 for ATP varied inversely with the rate of cell swelling. Activation of current was rapid (4–6 pA/pF per min) in the absence of ATP when cells were swollen at rates ≥65%/min. Intracellular ATP concentration had no effect on current activation induced by high rates of swelling. Current activation was transient when endogenous ATP was dialyzed out of the cytoplasm of cells swollen at 15%/min. Rundown of the current was reversed by increasing the rate of swelling to 65%/min. These results indicate that the channel and/or associated regulatory proteins are capable of sensing the rate of cell volume increase. We suggest that channel activation occurs via ATP-dependent and -independent mechanisms. Increasing the rate of cell swelling appears to increase the proportion of channels activating via the ATP-independent pathway. These findings have important physiological implications for understanding ICl, swell regulation, the mechanisms by which cells sense volume changes, and volume homeostasis under conditions where cell metabolism is compromised.

Regulation of Intracellular ATP Concentration under Conditions of Reduced ATP Consumption in Pancreatic Islets

1999 ◽  
Vol 261 (2) ◽  
pp. 439-444 ◽  
Author(s):  
Yoshiyuki Tsuura ◽  
Shimpei Fujimoto ◽  
Mariko Kajikawa ◽  
Hitoshi Ishida ◽  
Yutaka Seino
Keyword(s):  
Pancreatic Islets ◽  
Intracellular Atp ◽  
Atp Concentration
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