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Hamida RS, Ali MA, Goda DA, Khalil MI, Redhwan A. Cytotoxic effect of green silver nanoparticles against ampicillin-resistant Klebsiella pneumoniae. RSC Adv 2020; 10:21136-21146. [PMID: 35518759 PMCID: PMC9054378 DOI: 10.1039/d0ra03580g] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/28/2020] [Indexed: 11/29/2022] Open
Abstract
Considering the harmful effects and high spread of drug-resistant Klebsiella pneumoniae, many researchers have been trying to produce new antibacterial agents to combat the emergence of multidrug-resistant (MDR) strains of this bacterium. Recent progress in the nanomedicine field has provided opportunities for synthesizing unique nanoagents to battle MDR bacteria by targeting virulence and resistance signalling. The biocidal effects of 14.9 nm silver nanoparticles fabricated using Nostoc sp. Bahar M (N-SNPs) and AgNO3 were examined against drug-resistant K. pneumoniae using the agar well diffusion method. Transmission electron microscopy (TEM) was used to detect the ultrastructural changes caused by N-SNPs and AgNO3. To address the mode of action of N-SNPs and AgNO3, CAT, GPx, LDH and ATPase levels were assessed. The toxicity of N-SNPs and AgNO3 was evaluated against the mfD, flu, hly, 23S, hns, hcp-1, VgrG-1 and VgrG-3 genes as well as cellular proteins. N-SNPs showed the greatest inhibitory activity against K. pneumoniae, with MIC and MBC values of 0.9 and 1.2 mg mL-1, respectively. Furthermore, N-SNPs and AgNO3 induced apoptotic features, including cell shrinkage and cell atrophy. N-SNPs were more potent bactericidal compounds than AgNO3, causing increased leakage of LDH and GPx activities and depletion of ATPase and CAT activities, resulting in induced oxidative stress and metabolic toxicity. Compared to AgNO3, N-SNPs exhibited the highest toxicity towards the selected genes and the greatest damage to bacterial proteins. N-SNPs were the most potent agents that induced bacterial membrane damage, oxidative stress and disruption of biomolecules such as DNA and proteins. N-SNPs may be used as effective nanodrugs against MDR bacteria.
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Affiliation(s)
- Reham Samir Hamida
- Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University Egypt +201156298937
| | - Mohamed Abdelaal Ali
- Biotechnology Unit, Department of Plant Production, College of Food and Agriculture Science, King Saud University Riyadh Saudi Arabia
| | - Doaa A Goda
- Bioprocess Development Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City) Alexandria Egypt
| | - Mahmoud Ibrahim Khalil
- Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University Egypt +201156298937
- Department of Biological Sciences, Faculty of Science, Beirut Arab University Lebanon
| | - Alya Redhwan
- Department of Health, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University Riyadh Saudi Arabia +966555237223
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Hamida RS, Ali MA, Goda DA, Khalil MI, Al-Zaban MI. Novel Biogenic Silver Nanoparticle-Induced Reactive Oxygen Species Inhibit the Biofilm Formation and Virulence Activities of Methicillin-Resistant Staphylococcus aureus (MRSA) Strain. Front Bioeng Biotechnol 2020; 8:433. [PMID: 32548095 PMCID: PMC7270459 DOI: 10.3389/fbioe.2020.00433] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/15/2020] [Indexed: 12/20/2022] Open
Abstract
Emerging antibiotic-resistant bacteria result in increased mortality and have negative economic impacts. It is necessary to discover new strategies to create alternative antibacterial agents that suppress the bacterial resistance mechanism and limit the spread of serious infectious bacterial diseases. Silver nanoparticles may represent a new medicinal agents as alternative antibiotics affect different bacterial mechanisms such as virulence and resistance. In addition to that of silver nitrate (AgNO3) and ampicillin, for the first time, the inhibitory effect of silver nanoparticles synthesized using Desertifilum sp. (D-SNPs) was evaluated against five pathogenic bacteria using the agar well diffusion method. Also, the influence of D-SNPs and AgNO3 on bacterial antioxidant and metabolic activities was studied. The antibacterial activity of D-SNPs and AgNO3 against methicillin-resistant Staphylococcus aureus (MRSA) strains was studied at the morphological and molecular level. D-SNPs and AgNO3 have the ability to inhibit the growth of the five bacterial strains and resulted in an imbalance in the CAT, GSH, GPx and ATPase levels. MRSA treated with D-SNPs and AgNO3 showed different morphological changes such as apoptotic bodies formation and cell wall damage. Moreover, both caused genotoxicity and denaturation of MRSA cellular proteins. Additionally, TEM micrographs showed the distribution of SNPs synthesized by MRSA. This result shows the ability of MRSA to reduce silver nitrate into silver nanoparticles. These data indicate that D-SNPs may be a significant alternative antibacterial agent against different bacteria, especially MDR bacteria, by targeting the virulence mechanism and biofilm formation, leading to bacterial death.
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Affiliation(s)
- Reham Samir Hamida
- Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Mohamed Abdelaal Ali
- Biotechnology Unit, Department of Plant Production, College of Food and Agriculture Science, King Saud University, Riyadh, Saudi Arabia
| | - Doaa A Goda
- Bioprocess Development Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
| | - Mahmoud Ibrahim Khalil
- Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt.,Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, Lebanon
| | - Mayasar Ibrahim Al-Zaban
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
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Ma Q, Hu CT, Yue J, Luo Y, Qiao F, Chen LQ, Zhang ML, Du ZY. High-carbohydrate diet promotes the adaptation to acute hypoxia in zebrafish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2020; 46:665-679. [PMID: 31820205 DOI: 10.1007/s10695-019-00742-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Oxygen deprivation (hypoxia) is a common challenge in water environment, which causes lack of energy and oxidative damage in organisms. Many studies have indicated a number of physiological and metabolic changes under hypoxia, but the effects of dietary nutrients on hypoxia tolerance have not been well evaluated. In the present 7-week feeding trial, we fed zebrafish with low-protein diet (LP), high-protein diet (HP), low-fat diet (LF), high-fat diet (HF), low-carbohydrate diet (LC), and high-carbohydrate diet (HC), respectively. Afterward, the resistance to acute hypoxia challenge, growth, body composition, activities of metabolic enzymes, and expressions of energy homeostasis-related genes and six hifαs genes were measured. The results indicated that only the HC diet could significantly improve the resistance to hypoxia challenge. Moreover, the HC diet feeding caused higher glycogen deposition in the liver and muscle, and these glycogens were significantly reduced after 6-h acute hypoxia challenge. Meanwhile, the lactate content in the liver and blood was increased in the HC groups. At hypoxia status, the relative mRNA expressions of the genes related to glycolysis, ATP production, insulin signaling pathway, and hif-3a (hif1al) were all significantly increased in the muscle of the HC diet-fed fish. This study revealed that high-carbohydrate diet could improve the resistance to hypoxia by activating glycolysis and hif/insulin signaling pathway in zebrafish, mainly in the muscle, to efficiently supply energy. Therefore, our results highlight the importance of dietary carbohydrate in resisting hypoxia in fish.
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Affiliation(s)
- Qiang Ma
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Chun-Ting Hu
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Junjiayu Yue
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Yuan Luo
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Fang Qiao
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Li-Qiao Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China.
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Ding T, Wang S, Gao Y, Li C, Wan F, Zhang B. Toxicity and effects of four insecticides on Na +, K +-ATPase of western flower thrips, Frankliniella occidentalis. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:58-64. [PMID: 31784922 DOI: 10.1007/s10646-019-02139-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
Western flower thrips (WFT), Frankliniella occidentalis, has become an important pest of vegetables worldwide, due to its economic damage to crop production. In order to control WFT, chemical insecticides are widely used. However, WFT has developed a high resistance against many kinds of insecticides. Na+, K+-ATPase, playing an important role in the ionic transmission across the membrane, is commonly considered to be the target of several xenobiotic compounds. However, whether the Na+, K+-ATPase can be used as one of the target sites for controlling WFT is still unknown. In this study, resistance levels of WFT to four insecticides (chlorpyrifos, beta cypermethrin, abamectin, and thiamethoxam) were measured. It was found that all four insecticides exhibited significant inhibitory effects on WFT, especially on nymphs. The activity of Na+, K+-ATPase was estimated after the treatment of four insecticides. Additionally, mRNA expression levels of three Na+, K+-ATPase α-subunit isoforms (X1, X2 and X3) were detected using RT-qPCR. The transcription profile of three Na+, K+-ATPase α-subunit isoforms were diverse after treatment by these four insecticides, which indicated that these isoforms might play different roles in the tolerance to insecticides. The results suggested that Na+, K+-ATPase can obviously be inhibited by these four classes of insecticide, and may serve as the new target for controlling WFT.
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Affiliation(s)
- Tianbo Ding
- Key Lab of Integrated Crop Pest Management of Shandong, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, 266109, PR China
- China-Australia Joint Institute of Agricultural and Environmental Health, Qingdao Agricultural University, Qingdao, 266109, PR China
| | - Sifang Wang
- Key Lab of Integrated Crop Pest Management of Shandong, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, 266109, PR China
- China-Australia Joint Institute of Agricultural and Environmental Health, Qingdao Agricultural University, Qingdao, 266109, PR China
| | - Yulin Gao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, PR China
| | - Changyou Li
- Key Lab of Integrated Crop Pest Management of Shandong, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, 266109, PR China
- China-Australia Joint Institute of Agricultural and Environmental Health, Qingdao Agricultural University, Qingdao, 266109, PR China
| | - Fanghao Wan
- Key Lab of Integrated Crop Pest Management of Shandong, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, 266109, PR China
- China-Australia Joint Institute of Agricultural and Environmental Health, Qingdao Agricultural University, Qingdao, 266109, PR China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, PR China
| | - Bin Zhang
- Key Lab of Integrated Crop Pest Management of Shandong, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, 266109, PR China.
- China-Australia Joint Institute of Agricultural and Environmental Health, Qingdao Agricultural University, Qingdao, 266109, PR China.
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Akentieva NP, Sanina NA, Gizatullin AR, Shkondina NI, Prikhodchenko TR, Shram SI, Zhelev N, Aldoshin SM. Cytoprotective Effects of Dinitrosyl Iron Complexes on Viability of Human Fibroblasts and Cardiomyocytes. Front Pharmacol 2019; 10:1277. [PMID: 31780929 PMCID: PMC6859909 DOI: 10.3389/fphar.2019.01277] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/07/2019] [Indexed: 12/29/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule that plays a key role in maintaining vascular homeostasis. Dinitrosyl iron complexes (DNICs) generating NO are widely used to treat cardiovascular diseases. However, the involvement of DNICs in the metabolic processes of the cell, their protective properties in doxorubicin-induced toxicity remain to be clarified. Here, we found that novel class of mononuclear DNICs with functional sulfur-containing ligands enhanced the cell viability of human lung fibroblasts and rat cardiomyocytes. Moreover, DNICs demonstrated remarkable protection against doxorubicin-induced toxicity in fibroblasts and in rat cardiomyocytes (H9c2 cells). Data revealed that the DNICs compounds modulate the mitochondria function by decreasing the mitochondrial membrane potential (ΔΨm). Results of flow cytometry showed that DNICs were not affected the proliferation, growth of fibroblasts. In addition, this study showed that DNICs did not affect glutathione levels and the formation of reactive oxygen species in cells. Moreover, results indicated that DNICs maintained the ATP equilibrium in cells. Taken together, these findings show that DNICs have protective properties in vitro. It was further suggested that DNICs may be uncouplers of oxidative phosphorylation in mitochondria and protective mechanism is mainly provided by the leakage of excess charge through the mitochondrial membrane. It is assumed that the DNICs have the therapeutic potential for treating cardiovascular diseases and for decreasing of chemotherapy-induced cardiotoxicity in cancer survivors.
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Affiliation(s)
- Natalia Pavlovna Akentieva
- Laboratory Biochemical and Cellular Studies, Department of Kinetics of Chemical and Biological Processes, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
- Laboratory of Toxicology and Experimental Chemotherapy, Moscow State Regional University, Moscow, Russia
- Faculty of Medicine, Karabük University, Karabük, Turkey
| | - Natalia Alekseevna Sanina
- Laboratory of Structural Chemistry, Department of Structure of Matter, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
- Faculty of fundamental physical and chemical engineering, Lomonosov Moscow State University, Moscow, Russia
| | - Artur Rasimovich Gizatullin
- Laboratory Biochemical and Cellular Studies, Department of Kinetics of Chemical and Biological Processes, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
| | - Natalia Ivanovna Shkondina
- Laboratory Biochemical and Cellular Studies, Department of Kinetics of Chemical and Biological Processes, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
| | - Tatyana Romanovna Prikhodchenko
- Laboratory Biochemical and Cellular Studies, Department of Kinetics of Chemical and Biological Processes, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
| | - Stanislav Ivanovich Shram
- Neuropharmacology Sector, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Nikolai Zhelev
- School of Medicine, University of Dundee, Dundee, United Kingdom
- Medical University Plovdiv, Plovdiv, Bulgaria
| | - Sergei Michailovich Aldoshin
- Laboratory of Structural Chemistry, Department of Structure of Matter, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia
- Faculty of fundamental physical and chemical engineering, Lomonosov Moscow State University, Moscow, Russia
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Liu P, Du J, Zhang J, Wang J, Gu W, Wang W, Meng Q. The structural and proteomic analysis of Spiroplasma eriocheiris in response to colchicine. Sci Rep 2018; 8:8577. [PMID: 29872058 PMCID: PMC5988712 DOI: 10.1038/s41598-018-26614-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/23/2018] [Indexed: 11/18/2022] Open
Abstract
Spiroplasma eriocheiris, a pathogen that causes mass mortality of Chinese mitten crab Eriocheir sinensis, is a wall less bacteria and belongs to the Mollicutes. This study was designed to investigate the effects of colchicine on S. eriocheiris growth, cell morphology, and proteins expression. We found that in the presence of colchicine, the spiroplasma cells lost their helicity, and the length of the cells in the experimental group was longer than that of the control. With varying concentrations of the colchicine treatment, the total time to achieve a stationary phase of the spiroplasma was increased, and the cell population was decreased. The virulence ability of S. eriocheiris to E. sinensis was effectively reduced in the presence of colchicine. To expound the toxical mechanism of colchicine on S. eriocheiris, 208 differentially expressed proteins of S. eriocheiris were reliably quantified by iTRAQ analysis, including 77 up-regulated proteins and 131 down-regulated proteins. Especially, FtsY, putative Spiralin, and NADH oxidase were down-regulated. F0F1 ATP synthase subunit delta, ParB, DNABs, and NAD(FAD)-dependent dehydrogenase were up-regulated. A qRT-PCR was conducted to detect 7 expressed genes from the iTRAQ results during the incubation. The qRT-PCR results were consistent with the iTRAQ results. All of our results indicate that colchicine have a strong impact on the cell morphology and cellular metabolism of S. eriocheiris.
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Affiliation(s)
- Peng Liu
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China.,Department of Biology, College of Pharmacy and Biological Sciences, University of South China, Hengyang, 421001, P.R. China.,Hunan Province cooperative innovation Center for Molecular Target New Drug Study, Hengyang, 421001, P.R. China
| | - Jie Du
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Jia Zhang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Jian Wang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Wei Gu
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Wen Wang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Qingguo Meng
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China.
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7
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Geroski DH, Grosserode R, Edelhauser HF. A Comparison of Hepes and Bicarbonate Buffered Intraocular Irrigating Solutions: Effects on Endothelial Function in Human and Rabbit Corneas. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569528209079878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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9
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Abstract
Membrane potential of rabbit corneal endothelial cells measured using microelectrodes was -29.3 +/- 0.8 mV, n = 45, (mean +/- SEM). Histological location of Lucifer Yellow dye iontophoresed out of the microelectrode confirmed that the microelectrode was located intracellularly. The Lucifer Yellow diffused five to six cell diameters away from the impaled cell indicating endothelial cell coupling. Depolarization by ouabain (10(-4) M) and high extracellular potassium (potassium for sodium substitution) showed the cells to be responsive to changes in the bathing solution whilst impaled, that the cell membrane is more permeable to potassium than sodium and that membrane bound Na(+)-K(+)-ATPase activity generates the transmembrane electrolyte gradients.
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Affiliation(s)
- C G Wigham
- Department of Optometry and Vision Sciences, University of Wales College of Cardiff, UK
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10
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Holthöfer H, Siegel GJ, Tarkkanen A, Tervo T. Immunocytochemical localization of carbonic anhydrase, NaK-ATPase and the bicarbonate chloride exchanger in the anterior segment of the human eye. Acta Ophthalmol 1991; 69:149-54. [PMID: 1651641 DOI: 10.1111/j.1755-3768.1991.tb02704.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We examined immunohistochemically the localization of three transport enzymes (carbonic anhydrase, Ca-II; sodium-potassium-activated adenosine triphosphatase, NaK-ATPase; bicarbonate-chloride exchanger, band III) in the anterior segment of the human eye. In accord with earlier studies, NaK-ATPase was primarily found in the corneal endothelium, but also in the corneal basal epithelial cell membranes. In addition, immunoreactivity for NaK-ATPase was observed in the non-pigmented epithelium of the ciliary processes and between the two epithelial cell layers. Ca-II immunoreactivity was found in the corneal endothelium as well as in the non-pigmented epithelial layer of the ciliary processes. Interestingly, band III immunoreactivity was found in the corneal endothelium, as similar to Ca-II, but not in the ciliary processes. These results show that, similar to many other tissues, Ca-II and band III immunoreactivities colocalize in the same cytologic site in the human corneal endothelium. Immunocytochemical detection of these key transport enzymes not only gives their accurate and reliable anatomical distribution, but also provides information on the electrolyte transport at these sites.
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Affiliation(s)
- H Holthöfer
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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Hodson S, Hodson G. The absence of bicarbonate-stimulated ATPase activity in the plasma membranes of the bicarbonate secreting ox corneal endothelial cells. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 937:241-6. [PMID: 2827769 DOI: 10.1016/0005-2736(88)90246-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Membranes of ox corneal endothelial cells were studied for their surface area by electron microscopical stereology and then separated from homogenates on self forming Percoll gradients. Enzymic analysis of the plasma membrane-enriched fraction failed to demonstrate an ATPase activity which was stimulated by the presence of bicarbonate ions. It is proposed that the well-established bicarbonate secretion of these cells may be coupled to the plasma membrane (Na+ + K+)-ATPase activity by the stoichiometry of Na+/HCO3- close to 1:1.
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Affiliation(s)
- S Hodson
- Laboratory of Experimental Optometry, University of Wales Institute of Science and Technology, Cardiff, U.K
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Riley MV, Kishida K. ATPases of ciliary epithelium: cellular and subcellular distribution and probable role in secretion of aqueous humor. Exp Eye Res 1986; 42:559-68. [PMID: 3013667 DOI: 10.1016/0014-4835(86)90046-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The distribution of ion-stimulated ATPases of the ciliary epithelium has been examined in tissues from bovine and rabbit eyes. In homogenates of tissues from both species, both Na,K- and anion-stimulated enzyme activities were found, but no K,H-stimulated activity was detected. The anion ATPase had a broad specificity for a number of anions, and was strongly inhibited by thiocyanate. Following separation of pigmented (outer) and non-pigmented (inner) layers of the bovine ciliary epithelium and isolation of the two cell types on density gradients, higher activities of both Na,K- and anion ATPases were found in the non-pigmented cells. Subcellular fractionation of a mixed population of cells showed that the anion ATPase was almost exclusively associated with a mitochondrial fraction, rather than with the plasma-membrane fraction containing the Na,K-ATPase. These results confirm histochemical studies of the distribution of Na,K-ATPase in the ciliary epithelium and support the concept that the inner, non-pigmented cell layer is chiefly responsible for the active transport of ions into the posterior chamber. It is concluded that this transepithelial transport can be driven only by the energy derived via the Na,K-ATPase, and that any subsequent anion or proton transport in the formation of aqueous humor is driven by the sodium gradient through exchange mechanisms.
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Abstract
Unidirectional sodium and bicarbonate ion fluxes were measured under short-circuit conditions across rabbit corneal endothelium. A net flux of bicarbonate was measured, direction tears to lens, however no net flux of sodium was measured. From these experiments it seems that the inequality between electrically measured short-circuit current and net trans-endothelial bicarbonate ion flux cannot be bridged by any supposed net sodium flux.
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Abstract
In human cornea an anion sensitive ATPase is present. The highest specific activity was found in the endothelium, whereas the epithelium contained the highest total activity. The enzyme was stimulated by bicarbonate and sulfite and inhibited by thiocyanate. the majority of the enzyme was localized in the mitochondria but some activity was also detected in the plasma membranes. Atractyloside inhibited only the mitochondrial anion ATPase.
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15
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Jentsch TJ, Koch M, Bleckmann H, Wiederholt M. Effect of bicarbonate, pH, methazolamide and stilbenes on the intracellular potentials of cultured bovine corneal endothelial cells. J Membr Biol 1984; 78:103-17. [PMID: 6325699 DOI: 10.1007/bf01869198] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Micropuncture of cultured bovine corneal endothelial cells led to registrations stable for hours. Intracellular potentials were mainly in the range of -40 to -55 mV, average 46.3 +/- 0.6 mV (SEM). Changes of extracellular [HCO-3] led to voltage transients, their amplitude depending logarithmically on [HCO-3] with a mean slope of 37.3 +/- 8.8 (SD) mV. After removal of bicarbonate/CO2, a steady-state depolarization was seen. This steady-state depolarization, but not the voltage transients, could be reduced by 1 mM Ba++. After removal of bicarbonate, the voltage response to changes of extracellular potassium was reduced. Alteration of pHi induced by permeable buffers (butyrate, glycodiazine and ammonium) also resulted in voltage transients, internal acidification being correlated with a hyperpolarization, and internal alkalinization with a depolarization. Also changes of external pH caused voltage responses, alkalinization causing a hyperpolarization, acidification a depolarization. Methazolamide, an inhibitor of carbonic anhydrase, as well as stilbenes (SITS or DIDS) caused a reduction of the voltage response to HCO-3 and pH. Their effects were additive. It is suggested that corneal endothelial cells possess one or two electrogenic transporters for HCO-3 or related species, one of which is inhibitable by stilbenes.
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