1
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Zhang F, Yu Q, Huang Y, Luo Y, Qin J, Chen L, Li E, Wang X. Study on the osmotic response and function of myo-inositol oxygenase in euryhaline fish nile tilapia ( Oreochromis niloticus). Am J Physiol Cell Physiol 2024; 326:C1054-C1066. [PMID: 38344798 DOI: 10.1152/ajpcell.00513.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/29/2024] [Accepted: 01/29/2024] [Indexed: 03/13/2024]
Abstract
To understand the role of myo-inositol oxygenase (miox) in the osmotic regulation of Nile tilapia, its expression was analyzed in various tissues. The results showed that the expression of miox gene was highest in the kidney, followed by the liver, and was significantly upregulated in the kidney and liver under 1 h hyperosmotic stress. The relative luminescence efficiency of the miox gene transcription starting site (-4,617 to +312 bp) under hyperosmotic stress was measured. Two fragments (-1,640/-1,619 and -620/-599) could induce the luminescence activity. Moreover, the -1,640/-1,619 and -620/-599 responded to hyperosmotic stress and high-glucose stimulation by base mutation, suggesting that osmotic and carbohydrate response elements may exist in this region. Finally, the salinity tolerance of Nile tilapia was significantly reduced after the knocking down of miox gene. The accumulation of myo-inositol was affected, and the expression of enzymes in glucose metabolism was significantly reduced after the miox gene was knocked down. Furthermore, hyperosmotic stress can cause oxidative stress, and MIOX may help maintain the cell redox balance under hyperosmotic stress. In summary, MIOX is essential in osmotic regulation to enhance the salinity tolerance of Nile tilapia by affecting myo-inositol accumulation, glucose metabolism, and antioxidant performance.NEW & NOTEWORTHY Myo-inositol oxygenase (MIOX) is the rate-limiting enzyme that catalyzes the first step of MI metabolism and determines MI content in aquatic animals. To understand the role of miox in the osmotic regulation of Nile tilapia, we analyzed its expression in different tissues and its function under hyperosmotic stress. This study showed that miox is essential in osmotic regulation to enhance the salinity tolerance of Nile tilapia by affecting myo-inositol accumulation, glucose metabolism, and antioxidant performance.
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Affiliation(s)
- Fan Zhang
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Qiuran Yu
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Yuxing Huang
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Yuan Luo
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Jianguang Qin
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Liqiao Chen
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Erchao Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Xiaodan Wang
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
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2
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Nguyen VH, Wemheuer B, Song W, Bennett H, Palladino G, Burgsdorf I, Sizikov S, Steindler L, Webster NS, Thomas T. Functional characterization and taxonomic classification of novel gammaproteobacterial diversity in sponges. Syst Appl Microbiol 2023; 46:126401. [PMID: 36774720 DOI: 10.1016/j.syapm.2023.126401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 01/18/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
Sponges harbour exceptionally diverse microbial communities, whose members are largely uncultured. The class Gammaproteobacteria often dominates the microbial communities of various sponge species, but most of its diversity remains functional and taxonomically uncharacterised. Here we reconstructed and characterised 32 metagenome-assembled genomes (MAGs) derived from three sponge species. These MAGs represent ten novel species and belong to seven orders, of which one is new. We propose nomenclature for all these taxa. These new species comprise sponge-specific bacteria with varying levels of host specificity. Functional gene profiling highlights significant differences in metabolic capabilities across the ten species, though each also often exhibited a large degree of metabolic diversity involving various nitrogen- and sulfur-based compounds. The genomic features of the ten species suggest they have evolved to form symbiotic interaction with their hosts or are well-adapted to survive within the sponge environment. These Gammaproteobacteria are proposed to scavenge substrates from the host environment, including metabolites or cellular components of the sponge. Their diverse metabolic capabilities may allow for efficient cycling of organic matter in the sponge environment, potentially to the benefit of the host and other symbionts.
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Affiliation(s)
- Viet Hung Nguyen
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Bernd Wemheuer
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Weizhi Song
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Holly Bennett
- Australian Institute of Marine Science, Townsville, Queensland, Australia; Cawthron Institute, Nelson, New Zealand
| | - Giorgia Palladino
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia; Unit of Microbiome Science and Biotechnology, Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | | | | | | | - Nicole S Webster
- Australian Institute of Marine Science, Townsville, Queensland, Australia; Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia; Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Torsten Thomas
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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3
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Mikhaylova VV, Eronina TB, Chebotareva NA, Kurganov BI. The Effect of Chemical Chaperones on Proteins with Different Aggregation Kinetics. BIOCHEMISTRY (MOSCOW) 2023; 88:1-12. [PMID: 37068874 DOI: 10.1134/s0006297923010017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Formation and accumulation of protein aggregates adversely affect intracellular processes in living cells and are negative factors in the production and storage of protein preparations. Chemical chaperones can prevent protein aggregation, but this effect is not universal and depends on the target protein structure and kinetics of its aggregation. We studied the effect of betaine (Bet) and lysine (Lys) on thermal aggregation of muscle glycogen phosphorylase b (Phb) at 48°C (aggregation order, n = 0.5), UV-irradiated Phb (UV-Phb) at 37°C (n = 1), and apo-form of Phb (apo-Phb) at 37°C (n = 2). Using dynamic light scattering, differential scanning calorimetry, and analytical ultracentrifugation, we have shown that Bet protected Phb and apo-Phb from aggregation, but accelerated the aggregation of UV-Phb. At the same time, Lys prevented UV-Phb and apo-Phb aggregation, but increased the rate of Phb aggregation. The mechanisms of chemical chaperone action on the tertiary and quaternary structures and kinetics of thermal aggregation of the target proteins are discussed. Comparison of the effects of chemical chaperones on the proteins with different aggregation kinetics provides more complete information on the mechanism of their action.
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Affiliation(s)
- Valeriya V Mikhaylova
- Bach Institute of Biochemistry, Fundamentals of Biotechnology Federal Research Centre, Russian Academy of Sciences, Moscow, 119071, Russia.
| | - Tatiana B Eronina
- Bach Institute of Biochemistry, Fundamentals of Biotechnology Federal Research Centre, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Natalia A Chebotareva
- Bach Institute of Biochemistry, Fundamentals of Biotechnology Federal Research Centre, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Boris I Kurganov
- Bach Institute of Biochemistry, Fundamentals of Biotechnology Federal Research Centre, Russian Academy of Sciences, Moscow, 119071, Russia
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4
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Hyperosmotic stress allosterically reconfigures betaine binding pocket in BetP. J Mol Biol 2022; 434:167747. [PMID: 35870651 DOI: 10.1016/j.jmb.2022.167747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 12/18/2022]
Abstract
The transporter BetP in C. glutamicum is essential in maintaining bacterial cell viability during hyperosmotic stress and functions by co-transporting betaine and Na+ into bacterial cells. Hyperosmotic stress leads to increased intracellular K+ concentrations which in turn promotes betaine binding. While structural details of multiple end state conformations of BetP have provided high resolution snapshots, how K+ sensing by the C-terminal domain is allosterically relayed to the betaine binding site is not well understood. In this study, we describe conformational dynamics in solution of BetP using amide hydrogen/deuterium exchange mass spectrometry (HDXMS). These reveal how K+ alters conformation of the disordered C- and N-terminal domains to allosterically reconfigure transmembrane helices 3,8 and 10 (TM 3, 8, 10) to enhance betaine interactions. A map of the betaine binding site, at near single amino acid resolution, reveals a critical extrahelical H-bond mediated by TM3 with betaine.
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5
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Joshi PU, Turpeinen DG, Schroeder M, Jones B, Lyons A, Kriz S, Khaksari M, O'Hagan D, Nikam S, Heldt CL. Osmolyte enhanced aqueous two-phase system for virus purification. Biotechnol Bioeng 2021; 118:3251-3262. [PMID: 34129733 DOI: 10.1002/bit.27849] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 05/26/2021] [Accepted: 06/02/2021] [Indexed: 01/15/2023]
Abstract
Due to the high variation in viral surface properties, a platform method for virus purification is still lacking. A potential alternative to the high-cost conventional methods is aqueous two-phase systems (ATPSs). However, optimizing virus purification in ATPS requires a large experimental design space, and the optimized systems are generally found to operate at high ATPS component concentrations. The high concentrations capitalize on hydrophobic and electrostatic interactions to obtain high viral particle yields. This study investigated using osmolytes as driving force enhancers to reduce the high concentration of ATPS components while maintaining high yields. The partitioning behavior of porcine parvovirus (PPV), a nonenveloped mammalian virus, and human immunodeficiency virus-like particle (HIV-VLP), a yeast-expressed enveloped VLP, were studied in a polyethylene glycol (PEG) 12 kDa-citrate system. The partitioning of the virus modalities was enhanced by osmoprotectants glycine and betaine, while trimethylamine N-oxide was ineffective for PPV. The increased partitioning to the PEG-rich phase pertained only to viruses, resulting in high virus purification. Recoveries were 100% for infectious PPV and 92% for the HIV-VLP, with high removal of the contaminant proteins and more than 60% DNA removal when glycine was added. The osmolyte-induced ATPS demonstrated a versatile method for virus purification, irrespective of the expression system.
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Affiliation(s)
- Pratik U Joshi
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA.,Health Research Institute, Michigan Technological University, Houghton, Michigan, USA
| | - Dylan G Turpeinen
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA.,Health Research Institute, Michigan Technological University, Houghton, Michigan, USA
| | - Michael Schroeder
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Bianca Jones
- Department of Biochemistry, University of Detroit-Mercy, Detroit, Michigan, USA
| | - Audrey Lyons
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Seth Kriz
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA.,Health Research Institute, Michigan Technological University, Houghton, Michigan, USA
| | - Maryam Khaksari
- Great Lakes Research Center, Michigan Technological University, Houghton, Michigan, USA
| | | | | | - Caryn L Heldt
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA.,Health Research Institute, Michigan Technological University, Houghton, Michigan, USA
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6
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Rugiu L, de Wit P, Kostian I, Jormalainen V. Climate change driven hyposalinity as a selective agent in the littoral mesoherbivore Idotea balthica. MARINE ENVIRONMENTAL RESEARCH 2021; 163:105216. [PMID: 33227618 DOI: 10.1016/j.marenvres.2020.105216] [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] [Received: 08/21/2020] [Revised: 10/29/2020] [Accepted: 11/15/2020] [Indexed: 06/11/2023]
Abstract
Climate change will include a decrease in seawater salinity in the Baltic Sea. We quantified the effects of the projected future desalination on survival of the early life stage of the littoral herbivore Idotea balthica. We collected egg-bearing Idotea from three range-margin Baltic Sea populations, we exposed half of each brood to either current (6‰) or future salinity (3.5‰). We genotyped a subsample of each brood to analyse patterns of allelic change and to identify genomic regions targeted by selection. The survival was overall reduced by hyposalinity and broods varied in response to hyposalinity implying genetic variation in tolerance, with a stronger decrease in genetic diversity in future salinity. Finally, we identified proteins with crucial roles in basic cellular functions. This study indicates that projected future northern Baltic Sea hyposalinity will not just hamper I. balthica survival, but its selective pressure may also affect genetic diversity and cell physiology.
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Affiliation(s)
- Luca Rugiu
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden.
| | - Pierre de Wit
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Iita Kostian
- Section of Ecology, Department of Biology, University of Turku, Finland
| | - Veijo Jormalainen
- Section of Ecology, Department of Biology, University of Turku, Finland
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7
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Sampognaro L, Eirín K, Martínez de la Escalera G, Piccini C, Segura A, Kruk C. Experimental evidence on the effects of temperature and salinity in morphological traits of the Microcystis aeruginosa complex. J Microbiol Methods 2020; 175:105971. [DOI: 10.1016/j.mimet.2020.105971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 11/17/2022]
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8
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Dumas SJ, Meta E, Borri M, Goveia J, Rohlenova K, Conchinha NV, Falkenberg K, Teuwen LA, de Rooij L, Kalucka J, Chen R, Khan S, Taverna F, Lu W, Parys M, De Legher C, Vinckier S, Karakach TK, Schoonjans L, Lin L, Bolund L, Dewerchin M, Eelen G, Rabelink TJ, Li X, Luo Y, Carmeliet P. Single-Cell RNA Sequencing Reveals Renal Endothelium Heterogeneity and Metabolic Adaptation to Water Deprivation. J Am Soc Nephrol 2019; 31:118-138. [PMID: 31818909 DOI: 10.1681/asn.2019080832] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/01/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Renal endothelial cells from glomerular, cortical, and medullary kidney compartments are exposed to different microenvironmental conditions and support specific kidney processes. However, the heterogeneous phenotypes of these cells remain incompletely inventoried. Osmotic homeostasis is vitally important for regulating cell volume and function, and in mammals, osmotic equilibrium is regulated through the countercurrent system in the renal medulla, where water exchange through endothelium occurs against an osmotic pressure gradient. Dehydration exposes medullary renal endothelial cells to extreme hyperosmolarity, and how these cells adapt to and survive in this hypertonic milieu is unknown. METHODS We inventoried renal endothelial cell heterogeneity by single-cell RNA sequencing >40,000 mouse renal endothelial cells, and studied transcriptome changes during osmotic adaptation upon water deprivation. We validated our findings by immunostaining and functionally by targeting oxidative phosphorylation in a hyperosmolarity model in vitro and in dehydrated mice in vivo. RESULTS We identified 24 renal endothelial cell phenotypes (of which eight were novel), highlighting extensive heterogeneity of these cells between and within the cortex, glomeruli, and medulla. In response to dehydration and hypertonicity, medullary renal endothelial cells upregulated the expression of genes involved in the hypoxia response, glycolysis, and-surprisingly-oxidative phosphorylation. Endothelial cells increased oxygen consumption when exposed to hyperosmolarity, whereas blocking oxidative phosphorylation compromised endothelial cell viability during hyperosmotic stress and impaired urine concentration during dehydration. CONCLUSIONS This study provides a high-resolution atlas of the renal endothelium and highlights extensive renal endothelial cell phenotypic heterogeneity, as well as a previously unrecognized role of oxidative phosphorylation in the metabolic adaptation of medullary renal endothelial cells to water deprivation.
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Affiliation(s)
- Sébastien J Dumas
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Elda Meta
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Mila Borri
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Jermaine Goveia
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Katerina Rohlenova
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Nadine V Conchinha
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Kim Falkenberg
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Laure-Anne Teuwen
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Laura de Rooij
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Joanna Kalucka
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Rongyuan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Shawez Khan
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Federico Taverna
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Weisi Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Magdalena Parys
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Carla De Legher
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Stefan Vinckier
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Tobias K Karakach
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Luc Schoonjans
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Lin Lin
- Lars Bolund Institute of Regenerative Medicine, Beijing Genomics Institute (BGI)-Qingdao, BGI-Shenzhen, Qingdao, China.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Lars Bolund
- Lars Bolund Institute of Regenerative Medicine, Beijing Genomics Institute (BGI)-Qingdao, BGI-Shenzhen, Qingdao, China.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Mieke Dewerchin
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Guy Eelen
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Ton J Rabelink
- Division of Nephrology, Department of Internal Medicine, The Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Xuri Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China;
| | - Yonglun Luo
- Lars Bolund Institute of Regenerative Medicine, Beijing Genomics Institute (BGI)-Qingdao, BGI-Shenzhen, Qingdao, China; .,Department of Biomedicine, Aarhus University, Aarhus, Denmark.,China National GeneBank, Beijing Genomics Institute (BGI)-Shenzhen, Shenzhen, China; and.,Qingdao-Europe Advanced Institute for Life Sciences, Beijing Genomics Institute (BGI)-Qingdao, Qingdao, China
| | - Peter Carmeliet
- Department of Oncology, Laboratory of Angiogenesis and Vascular Metabolism, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium; .,Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
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9
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Lai JC, Kam YC, Lin HC, Wu CS. Enhanced salt tolerance of euryhaline tadpoles depends on increased Na+, K+-ATPase expression after salinity acclimation. Comp Biochem Physiol A Mol Integr Physiol 2019; 227:84-91. [DOI: 10.1016/j.cbpa.2018.09.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022]
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10
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Han YJ, Jo A, Kim SW, Lee HE, Kim YC, Jeong HD, Choi YH, Kim S, Cha HJ, Kim HS. Multiplex PCR using YeaD and 16S rRNA gene to identify major pathogens in vibriosis of Litopenaeus vannamei. Genes Genomics 2018; 41:35-42. [DOI: 10.1007/s13258-018-0736-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022]
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11
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Kessler RW, Weiss A, Kuegler S, Hermes C, Wichard T. Macroalgal-bacterial interactions: Role of dimethylsulfoniopropionate in microbial gardening byUlva(Chlorophyta). Mol Ecol 2018; 27:1808-1819. [DOI: 10.1111/mec.14472] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 02/02/2023]
Affiliation(s)
- Ralf W. Kessler
- Friedrich Schiller University Jena; Institute for Inorganic and Analytical Chemistry; Jena Germany
| | - Anne Weiss
- Friedrich Schiller University Jena; Institute for Inorganic and Analytical Chemistry; Jena Germany
- Jena School for Microbial Communication; Jena Germany
| | - Stefan Kuegler
- Friedrich Schiller University Jena; Institute for Inorganic and Analytical Chemistry; Jena Germany
| | - Cornelia Hermes
- Friedrich Schiller University Jena; Institute for Inorganic and Analytical Chemistry; Jena Germany
| | - Thomas Wichard
- Friedrich Schiller University Jena; Institute for Inorganic and Analytical Chemistry; Jena Germany
- Jena School for Microbial Communication; Jena Germany
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12
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Serrano R, Montesinos C. Molecular Bases of Desiccation Tolerance in Plant Cells and Potential Applications in Food Dehydration. FOOD SCI TECHNOL INT 2016. [DOI: 10.1177/1082013203035518] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Desiccation has many detrimental effects on the structure and function of biological membranes and proteins and this molecular damage decreases the freshness appearance of dehydrated foods. Phospholipid membranes are destabilised upon water stress by insertion of cellular amphiphiles, phase transition into the gel phase and membrane fusion. Proteins are denatured and electron transport chains are perturbed leading to increased formation of reactive oxygen species which cause irreversible damage of cellular structures. Cells respond to water stress by generating defense proteins and metabolites and eventually develop outstanding desiccation tolerance such as in the case of plant seeds and pollen, fungal spores, crustacean cysts, etc. The molecular bases for this remarkable phenomenon are not completely understood but several important principles have been identified. Three biological systems seem to act in concert to achieve desiccation tolerance: enzymes involved in osmolyte synthesis; proteins specialised in desiccation protection of membranes and proteins (LEA proteins), and antioxidant enzymes and molecules. Both osmolytes and LEA proteins contribute to stabilisation of membrane and protein structures by conferring preferential hydration at moderate desiccation and replacing water at extreme desiccation. Osmolytes also contribute to osmotic adjustment and act as hydroxyl radical scavengers. Genetically modified plants with increased production of these defenses could be useful to improve the quality of dried food.
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Affiliation(s)
- R. Serrano
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC. Camino de Vera s/n, 46022 Valencia, Spain
| | - C. Montesinos
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC. Camino de Vera s/n, 46022 Valencia, Spain
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Pasantes-Morales H. Channels and Volume Changes in the Life and Death of the Cell. Mol Pharmacol 2016; 90:358-70. [PMID: 27358231 DOI: 10.1124/mol.116.104158] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/22/2016] [Indexed: 12/11/2022] Open
Abstract
Volume changes deviating from original cell volume represent a major challenge for cellular homeostasis. Cell volume may be altered either by variations in the external osmolarity or by disturbances in the transmembrane ion gradients that generate an osmotic imbalance. Cells respond to anisotonicity-induced volume changes by active regulatory mechanisms that modify the intracellular/extracellular concentrations of K(+), Cl(-), Na(+), and organic osmolytes in the direction necessary to reestablish the osmotic equilibrium. Corrective osmolyte fluxes permeate across channels that have a relevant role in cell volume regulation. Channels also participate as causal actors in necrotic swelling and apoptotic volume decrease. This is an overview of the types of channels involved in either corrective or pathologic changes in cell volume. The review also underlines the contribution of transient receptor potential (TRP) channels, notably TRPV4, in volume regulation after swelling and describes the role of other TRPs in volume changes linked to apoptosis and necrosis. Lastly we discuss findings showing that multimers derived from LRRC8A (leucine-rich repeat containing 8A) gene are structural components of the volume-regulated Cl(-) channel (VRAC), and we underline the intriguing possibility that different heteromer combinations comprise channels with different intrinsic properties that allow permeation of the heterogenous group of molecules acting as organic osmolytes.
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Affiliation(s)
- Herminia Pasantes-Morales
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Biller A, Reuter M, Patenaude B, Homola GA, Breuer F, Bendszus M, Bartsch AJ. Responses of the Human Brain to Mild Dehydration and Rehydration Explored In Vivo by 1H-MR Imaging and Spectroscopy. AJNR Am J Neuroradiol 2015; 36:2277-84. [PMID: 26381562 DOI: 10.3174/ajnr.a4508] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 05/06/2015] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND PURPOSE As yet, there are no in vivo data on tissue water changes and associated morphometric changes involved in the osmo-adaptation of normal brains. Our aim was to evaluate osmoadaptive responses of the healthy human brain to osmotic challenges of de- and rehydration by serial measurements of brain volume, tissue fluid, and metabolites. MATERIALS AND METHODS Serial T1-weighted and (1)H-MR spectroscopy data were acquired in 15 healthy individuals at normohydration, on 12 hours of dehydration, and during 1 hour of oral rehydration. Osmotic challenges were monitored by serum measures, including osmolality and hematocrit. MR imaging data were analyzed by using FreeSurfer and LCModel. RESULTS On dehydration, serum osmolality increased by 0.67% and brain tissue fluid decreased by 1.63%, on average. MR imaging morphometry demonstrated corresponding decreases of cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus. These changes reversed during rehydration. Continuous fluid ingestion of 1 L of water for 1 hour within the scanner lowered serum osmolality by 0.96% and increased brain tissue fluid by 0.43%, on average. Concomitantly, cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus increased. Changes in brain tissue fluid were related to volume changes of the whole brain, the white matter, and hypothalamus/thalamus. Only volume changes of the hypothalamus/thalamus significantly correlated with serum osmolality. CONCLUSIONS This is the first study simultaneously evaluating changes in brain tissue fluid, metabolites, volume, and cortical thickness. Our results reflect cellular volume regulatory mechanisms at a macroscopic level and emphasize that it is essential to control for hydration levels in studies on brain morphometry and metabolism in order to avoid confounding the findings.
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Affiliation(s)
- A Biller
- From the Department of Neuroradiology (A.B., M.B., A.J.B.), University of Heidelberg, Heidelberg, Germany
| | - M Reuter
- Department of Radiology (M.R.), Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts Martinos Center for Biomedical Imaging (M.R.), Charlestown, Massachusetts Massachusetts Institute of Technology Computer Science and AI Lab (M.R.), Cambridge, Massachusetts
| | - B Patenaude
- Department of Psychiatry and Behavioral Sciences (B.P.), Stanford University, Stanford, California Department of Clinical Neurology (B.P., A.J.B.), FMRIB Centre, University of Oxford, Oxford, UK
| | - G A Homola
- Department of Neuroradiology (G.A.H., A.J.B.), University of Würzburg, Würzburg, Germany
| | - F Breuer
- Research Center for Magnetic-Resonance-Bavaria (F.B.), Würzburg, Germany
| | - M Bendszus
- From the Department of Neuroradiology (A.B., M.B., A.J.B.), University of Heidelberg, Heidelberg, Germany
| | - A J Bartsch
- From the Department of Neuroradiology (A.B., M.B., A.J.B.), University of Heidelberg, Heidelberg, Germany Department of Clinical Neurology (B.P., A.J.B.), FMRIB Centre, University of Oxford, Oxford, UK Department of Neuroradiology (G.A.H., A.J.B.), University of Würzburg, Würzburg, Germany
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15
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Wrange AL, André C, Lundh T, Lind U, Blomberg A, Jonsson PJ, Havenhand JN. Importance of plasticity and local adaptation for coping with changing salinity in coastal areas: a test case with barnacles in the Baltic Sea. BMC Evol Biol 2014; 14:156. [PMID: 25038588 PMCID: PMC4223505 DOI: 10.1186/1471-2148-14-156] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 06/30/2014] [Indexed: 11/30/2022] Open
Abstract
Background Salinity plays an important role in shaping coastal marine communities. Near-future climate predictions indicate that salinity will decrease in many shallow coastal areas due to increased precipitation; however, few studies have addressed this issue. The ability of ecosystems to cope with future changes will depend on species’ capacities to acclimatise or adapt to new environmental conditions. Here, we investigated the effects of a strong salinity gradient (the Baltic Sea system – Baltic, Kattegat, Skagerrak) on plasticity and adaptations in the euryhaline barnacle Balanus improvisus. We used a common-garden approach, where multiple batches of newly settled barnacles from each of three different geographical areas along the Skagerrak-Baltic salinity gradient were exposed to corresponding native salinities (6, 15 and 30 PSU), and phenotypic traits including mortality, growth, shell strength, condition index and reproductive maturity were recorded. Results We found that B. improvisus was highly euryhaline, but had highest growth and reproductive maturity at intermediate salinities. We also found that low salinity had negative effects on other fitness-related traits including initial growth and shell strength, although mortality was also lowest in low salinity. Overall, differences between populations in most measured traits were weak, indicating little local adaptation to salinity. Nonetheless, we observed some population-specific responses – notably that populations from high salinity grew stronger shells in their native salinity compared to the other populations, possibly indicating adaptation to differences in local predation pressure. Conclusions Our study shows that B. improvisus is an example of a true brackish-water species, and that plastic responses are more likely than evolutionary tracking in coping with future changes in coastal salinity.
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Affiliation(s)
- Anna-Lisa Wrange
- Department of Biological and Environmental Sciences-Tjärnö, University of Gothenburg, S-45296 Strömstad, Sweden.
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Long-term osmotic regulation of amino acid transport systems in mammalian cells. Amino Acids 2013; 11:135-51. [PMID: 24178684 DOI: 10.1007/bf00813857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/1995] [Accepted: 01/10/1996] [Indexed: 01/05/2023]
Abstract
Mammalian cells accumulate organic osmolytes, either to adapt to permanent osmotic changes or to mediate cell volume increase in cell cycle progression. Amino acids may serve as osmolytes in a great variety of cells. System A, a transport system for neutral amino acids, is induced after hypertonic shock by a mechanism which requires protein synthesis and gene transcription. Indirect evidence supports the view that system A activity increases due to the interaction of pre-existing A carriers with putative activating proteins. The intracellular accumulation of most neutral amino acids after hypertonic shock depends, exclusively, on the increase in system A activity. Long-term activation of system A is dependent on the integrity of cytoskeletal structures, but in a different way depending on whether cells are polarized or not.
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Gebser B, Pohnert G. Synchronized regulation of different zwitterionic metabolites in the osmoadaption of phytoplankton. Mar Drugs 2013; 11:2168-82. [PMID: 23774888 PMCID: PMC3721227 DOI: 10.3390/md11062168] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 04/23/2013] [Accepted: 05/28/2013] [Indexed: 11/16/2022] Open
Abstract
The ability to adapt to different seawater salinities is essential for cosmopolitan marine phytoplankton living in very diverse habitats. In this study, we examined the role of small zwitterionic metabolites in the osmoadaption of two common microalgae species Emiliania huxleyi and Prorocentrum minimum. By cultivation of the algae under salinities between 16‰ and 38‰ and subsequent analysis of dimethylsulfoniopropionate (DMSP), glycine betaine (GBT), gonyol, homarine, trigonelline, dimethylsulfonioacetate, trimethylammonium propionate, and trimethylammonium butyrate using HPLC-MS, we could reveal two fundamentally different osmoadaption mechanisms. While E. huxleyi responded with cell size reduction and a nearly constant ratio between the major metabolites DMSP, GBT and homarine to increasing salinity, osmolyte composition of P. minimum changed dramatically. In this alga DMSP concentration remained nearly constant at 18.6 mM between 20‰ and 32‰ but the amount of GBT and dimethylsulfonioacetate increased from 4% to 30% of total investigated osmolytes. Direct quantification of zwitterionic metabolites via LC-MS is a powerful tool to unravel the complex osmoadaption and regulation mechanisms of marine phytoplankton.
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Affiliation(s)
| | - Georg Pohnert
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University, Lessingstr. 8, D-07743 Jena, Germany; E-Mail:
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18
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Somero GN, Yancey PH. Osmolytes and Cell‐Volume Regulation: Physiological and Evolutionary Principles. Compr Physiol 2011. [DOI: 10.1002/cphy.cp140110] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Characterization of osmolyte betaine synthesizing sarcosine dimethylglycine N-methyltransferase from Methanohalophilus portucalensis. Arch Microbiol 2009; 191:735-43. [DOI: 10.1007/s00203-009-0501-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 07/23/2009] [Accepted: 08/05/2009] [Indexed: 10/20/2022]
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20
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Molecular basis of transport and regulation in the Na+/betaine symporter BetP. Nature 2009; 458:47-52. [DOI: 10.1038/nature07819] [Citation(s) in RCA: 274] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Accepted: 01/21/2009] [Indexed: 11/08/2022]
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Foster C, Amado EM, Souza MM, Freire CA. Do osmoregulators have lower capacity of muscle water regulation than osmoconformers? A study on decapod crustaceans. ACTA ACUST UNITED AC 2009; 313:80-94. [DOI: 10.1002/jez.575] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Fedorova MZ, Pavlov NA, Zubareva EV, Nadezhdin SV, Simonov VV, Zabinyakov NA, Tveritina ES. The use of atomic force microscopy for estimating morphometric characteristics of blood cell. Biophysics (Nagoya-shi) 2008. [DOI: 10.1134/s000635090806016x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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23
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Fedorova MZ, Nadezhdin SV, Golovko SI, Zubareva EV. Comparative estimation of the “Membrane Reserve” of blood cells of reptiles and mammals. J EVOL BIOCHEM PHYS+ 2007. [DOI: 10.1134/s0022093007050076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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Lai MC, Wang CC, Chuang MJ, Wu YC, Lee YC. Effects of substrate and potassium on the betaine-synthesizing enzyme glycine sarcosine dimethylglycine N-methyltransferase from a halophilic methanoarchaeon Methanohalophilus portucalensis. Res Microbiol 2006; 157:948-55. [PMID: 17098399 DOI: 10.1016/j.resmic.2006.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 07/31/2006] [Accepted: 08/29/2006] [Indexed: 10/24/2022]
Abstract
Methanohalophilus portucalensis FDF1 can synthesize the compatible solute betaine de novo through the methylation of glycine, sarcosine and dimethylglycine with the methyl group from S-adenosylmethionine. After separation by DEAE-Sephacel ion chromatography using a KCl step gradient, glycine, sarcosine and dimethylglycine methytransfer (GSDMT) activities were detected in a single peak. The estimated molecular weight of GSDMT was 240 kDa and 2-D gel analysis indicated it was separated into four subunits (52 kDa) with different pI. The PBE94 chromatofocusing column also separated GSDMT into four protein peaks A, B, C, D. Both peak B and D proteins possessed GSDMT activity, while the peak A protein only exhibited SDMT activity. The multiple methyltransferase activities of the large complex appear to be unique compared to other methyltransferases used in betaine synthesis. Further methyltransferase assays in response to different concentrations of KCl indicated that the peak D protein exhibited low GSDMT activity only when K(+) < or = 0.4 M. The peak B protein exhibited a higher GSDMT activity at 0.4 M K(+), while the peak A protein exhibited SDMT activity only at higher K(+) (0.8 M). These results suggest that the internal K(+) concentration regulates GSDMT activities and affects the net betaine accumulation in the cells.
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Affiliation(s)
- Mei-Chin Lai
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC.
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25
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Cornet M. Effects of seawater salinity fluctuations on primary tissue culture from the mussel Mytilus galloprovincialis Potential application to the detection of seawater genotoxicity. Toxicol In Vitro 2006; 20:1500-5. [PMID: 16806799 DOI: 10.1016/j.tiv.2006.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 03/31/2006] [Accepted: 05/12/2006] [Indexed: 10/24/2022]
Abstract
The present results were obtained in the context of an attempt to develop an in vitro test intended to assess the genotoxicity of seawater. It is based on a short-term culture method of mussel mantle explants that gives mitotic cells in which DNA damage is likely to be detected. Its principle consists of the incorporation of the seawater to be tested in the culture medium. Two factors that influence cell proliferation were studied: (1) salinity of seawater and (2) basic composition of the culture medium i.e. replacement of Eagle's Basal Medium (BME) by Eagle's Minimum Essential Medium (MEM). When culture medium contained BME, a salinity change from 35 per thousand to 28 per thousand (that is the case for coastal or estuarine waters) resulted in a significant reduction of cell proliferation. In contrast, when culture medium was prepared with MEM, the same decrease of salinity did not change significantly the number of metaphase cells obtained. This suggested medium prepared with MEM allowed tissues in culture to better withstand the hypoosmotic shock generated by 28 per thousand seawater. This has been attributed to amino acids the concentration of which being higher in MEM than in BME. Direct and indirect mechanisms of osmoregulation are suggested to explain the observations. These results show that the test proposed could be used to assess the genotoxicity of coastal or estuarine seawater with salinity comprised from 28 per thousand to 35 per thousand, provided that MEM is used.
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Affiliation(s)
- Michel Cornet
- UMR 5805, Environnements et Paléoenvironnements Océaniques (EPOC), Université Bordeaux 1-CNRS, Avenue des Facultés, 33405 Talence Cedex, France.
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Wehner F, Olsen H, Tinel H, Kinne-Saffran E, Kinne RKH. Cell volume regulation: osmolytes, osmolyte transport, and signal transduction. Rev Physiol Biochem Pharmacol 2004; 148:1-80. [PMID: 12687402 DOI: 10.1007/s10254-003-0009-x] [Citation(s) in RCA: 241] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In recent years, it has become evident that the volume of a given cell is an important factor not only in defining its intracellular osmolality and its shape, but also in defining other cellular functions, such as transepithelial transport, cell migration, cell growth, cell death, and the regulation of intracellular metabolism. In addition, besides inorganic osmolytes, the existence of organic osmolytes in cells has been discovered. Osmolyte transport systems-channels and carriers alike-have been identified and characterized at a molecular level and also, to a certain extent, the intracellular signals regulating osmolyte movements across the plasma membrane. The current review reflects these developments and focuses on the contributions of inorganic and organic osmolytes and their transport systems in regulatory volume increase (RVI) and regulatory volume decrease (RVD) in a variety of cells. Furthermore, the current knowledge on signal transduction in volume regulation is compiled, revealing an astonishing diversity in transport systems, as well as of regulatory signals. The information available indicates the existence of intricate spatial and temporal networks that control cell volume and that we are just beginning to be able to investigate and to understand.
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Affiliation(s)
- F Wehner
- Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.
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Clowes LA, Francesconi KA. Uptake and elimination of arsenobetaine by the mussel Mytilus edulis is related to salinity. Comp Biochem Physiol C Toxicol Pharmacol 2004; 137:35-42. [PMID: 14984702 DOI: 10.1016/j.cca.2003.11.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 11/06/2003] [Accepted: 11/07/2003] [Indexed: 11/17/2022]
Abstract
The high concentrations of the naturally occurring arsenic compound arsenobetaine in marine animals, in comparison with freshwater animals, has led to the suggestion that salinity is a factor in its accumulation. In separate experiments, we investigated the uptake and elimination of arsenobetaine by the mussel Mytilus edulis when maintained under three salinity regimes (32, 24, and 16 practical salinity units). Both uptake and elimination of arsenobetaine depended on the salinity of the water in a manner leading to higher concentrations at the higher salinity. The data are consistent with a proposed role of arsenobetaine as an adventitiously acquired osmolyte, and readily explain field data for freshwater and marine animals.
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de Vooys CGN, Geenevasen JAJ. Biosynthesis and role in osmoregulation of glycine-betaine in the Mediterranean mussel Mytilus galloprovincialis LMK. Comp Biochem Physiol B Biochem Mol Biol 2002; 132:409-14. [PMID: 12031467 DOI: 10.1016/s1096-4959(02)00052-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Quaternary bases, for example glycine-betaine, are difficult to quantify in biological materials because of a lack of specificity. However, nuclear magnetic resonance (NMR) can determine quaternary bases even in the presence of high water concentrations. Using NMR concentrations of glycine-betaine, the posterior adductor muscle of the Mediterranean mussel Mytilus galloprovincialis were measured up to 256 micromole/g dry weight. These concentrations were related to external salinity concentrations. The biosynthesis of glycine-betaine was demonstrated in M. galloprovincialis from the precursor (14)C choline.
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Affiliation(s)
- C G N de Vooys
- Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands.
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30
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Sleator RD, Hill C. Bacterial osmoadaptation: the role of osmolytes in bacterial stress and virulence. FEMS Microbiol Rev 2002; 26:49-71. [PMID: 12007642 DOI: 10.1111/j.1574-6976.2002.tb00598.x] [Citation(s) in RCA: 480] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Two general strategies exist for the growth and survival of prokaryotes in environments of elevated osmolarity. The 'salt in cytoplasm' approach, which requires extensive structural modifications, is restricted mainly to members of the Halobacteriaceae. All other species have convergently evolved to cope with environments of elevated osmolarity by the accumulation of a restricted range of low molecular mass molecules, termed compatible solutes owing to their compatibility with cellular processes at high internal concentrations. Herein we review the molecular mechanisms governing the accumulation of these compounds, both in Gram-positive and Gram-negative bacteria, focusing specifically on the regulation of their transport/synthesis systems and the ability of these systems to sense and respond to changes in the osmolarity of the extracellular environment. Finally, we examine the current knowledge on the role of these osmostress responsive systems in contributing to the virulence potential of a number of pathogenic bacteria.
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Affiliation(s)
- Roy D Sleator
- Department of Microbiology and National Food Biotechnology Centre, University College Cork, Cork, Ireland
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31
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de Eguileor M, Leonardi MG, Grimaldi A, Tettamanti G, Fiandra L, Giordana B, Valvassori R, Lanzavecchia G. Integumental amino acid uptake in a carnivorous predator mollusc (Sepia officinalis, Cephalopoda). Tissue Cell 2000; 32:389-98. [PMID: 11201278 DOI: 10.1054/tice.2000.0127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The epithelial cells of the integument of body, arms and tentacles of Sepia officinalis present on their apical membrane a well-organised brush border and show the morphological and histochemical characteristics of a typical absorptive epithelium. The ability of the integument to absorb amino acids was investigated both in the arms incubated in vitro and in a purified preparation of brush border membrane vesicles (BBMV). Autoradiographic pictures of the integument after incubation of the arms in sea-water with or without sodium, showed that proline intake was Na+-dependent, whereas leucine intake appeared to be a largely cation-independent process. Time course experiments of labelled leucine, proline and lysine uptakes in BBMV evidenced that these amino acids are accumulated within the vesicles in the presence of an inwardly directed sodium gradient. The sodium-driven accumulation proves that cationic and neutral amino acids are taken up by the apical membrane of the epithelium of Sepia integument through a secondary active mechanism. For leucine, a 90% inhibition of the uptake was recorded in the presence of a large excess of the substrate. In agreement with the autoradiography results, an analysis of the cation specificity transport in BBMV showed that leucine uptake had a low cation specificity, whereas lysine and proline uptakes were Na+-dependent. An excess of lysine and proline, which share with alanine two different transport systems in the gill epithelium of marine bivalves, reduced eucine uptake. The possible role of the absorptive ability of the integument in a carnivorous mollusc is discussed.
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32
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Lai MC, Hong TY, Gunsalus RP. Glycine betaine transport in the obligate halophilic archaeon Methanohalophilus portucalensis. J Bacteriol 2000; 182:5020-4. [PMID: 10940053 PMCID: PMC111389 DOI: 10.1128/jb.182.17.5020-5024.2000] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transport of the osmoprotectant glycine betaine was investigated using the glycine betaine-synthesizing microbe Methanohalophilus portucalensis (strain FDF1), since solute uptake for this class of obligate halophilic methanogenic Archaea has not been examined. Betaine uptake followed a Michaelis-Menten relationship, with an observed K(t) of 23 microM and a V(max) of 8 nmol per min per mg of protein. The transport system was highly specific for betaine: choline, proline, and dimethylglycine did not significantly compete for [(14)C]betaine uptake. The proton-conducting uncoupler 2, 4-dinitrophenol and the ATPase inhibitor N, N-dicyclohexylcarbodiimide both inhibited glycine betaine uptake. Growth of cells in the presence of 500 microM betaine resulted in faster cell growth due to the suppression of the de novo synthesis of the other compatible solutes, alpha-glutamate, beta-glutamine, and N(epsilon)-acetyl-beta-lysine. These investigations demonstrate that this model halophilic methanogen, M. portucalensis strain FDF1, possesses a high-affinity and highly specific betaine transport system that allows it to accumulate this osmoprotectant from the environment in lieu of synthesizing this or other osmoprotectants under high-salt growth conditions.
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Affiliation(s)
- M C Lai
- Department of Botany, National Chung-Hsing University, Taichung, Taiwan, Republic of China.
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Grant AC, Thomson J, Zammit VA, Shennan DB. Volume-sensitive amino acid efflux from a pancreatic beta-cell line. Mol Cell Endocrinol 2000; 162:203-10. [PMID: 10854713 DOI: 10.1016/s0303-7207(99)00260-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cell swelling, induced by a hyposmotic shock, increased the fractional release of taurine from INS-1 cells. Volume-sensitive taurine release was (a) dependent upon the extent of cell swelling; (b) fully reversible; and (c) temperature dependent. Volume-sensitive taurine efflux was independent from the trans-membrane Na(+)-gradient. DIDS markedly inhibited volume-activated taurine efflux but not basal taurine release suggesting that the volume-sensitive pathway is quiescent under isosmotic conditions. Volume-activated taurine release inactivated in the continued presence of a hyposmotic shock. Cell-swelling also increased the fractional release of D-aspartate from INS-1 cells. Volume-activated D-aspartate efflux was inhibited by DIDS, albeit to a lesser extent than volume-sensitive taurine release. It is predicted that volume-sensitive amino acid efflux acts in parallel with other volume-activated transport mechanisms to regulate the volume of insulin-secreting cells.
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Affiliation(s)
- A C Grant
- Hannah Research Institute, Scotland, Ayr, UK
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Pierce VA, Mueller LD, Gibbs AG. Osmoregulation in Drosophila melanogaster selected for urea tolerance. J Exp Biol 1999; 202:2349-58. [PMID: 10441086 DOI: 10.1242/jeb.202.17.2349] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Animals may adapt to hyperosmolar environments by either osmoregulating or osmoconforming. Osmoconforming animals generally accumulate organic osmolytes including sugars, amino acids or, in a few cases, urea. In the latter case, they also accumulate ‘urea-counteracting’ solutes to mitigate the toxic effects of urea. We examined the osmoregulatory adaptation of Drosophila melanogaster larvae selected to live in 300 mmol l(−)(1) urea. Larvae are strong osmoregulators in environments with high NaCl or sucrose levels, but have increased hemolymph osmolarity on urea food. The increase in osmolarity on urea food is smaller in the selected larvae relative to unselected control larvae, and their respective hemolymph urea concentrations can account for the observed increases in total osmolarity. No other hemolymph components appear to act as urea-counteractants. Urea is calculated to be in equilibrium across body compartments in both selected and control larvae, indicating that the selected larvae are not sequestering it to lower their hemolymph osmolarity. The major physiological adaptation to urea does not appear to involve increased tolerance or improved osmoregulation per se, but rather mechanisms (e.g. metabolism, decreased uptake or increased excretion) that reduce overall urea levels and the consequent toxicity.
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Affiliation(s)
- V A Pierce
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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Lai MC, Yang DR, Chuang MJ. Regulatory factors associated with synthesis of the osmolyte glycine betaine in the halophilic methanoarchaeon Methanohalophilus portucalensis. Appl Environ Microbiol 1999; 65:828-33. [PMID: 9925623 PMCID: PMC91102 DOI: 10.1128/aem.65.2.828-833.1999] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The halophilic methanoarchaeon Methanohalophilus portucalensis can synthesize de novo and accumulate beta-glutamine, Nepsilon-acetyl-beta-lysine, and glycine betaine (betaine) as compatible solutes (osmolytes) when grown at elevated salt concentrations. Both in vivo and in vitro betaine formation assays in this study confirmed previous nuclear magnetic resonance 13C-labelling studies showing that the de novo synthesis of betaine proceeded from glycine, sarcosine, and dimethylglycine to form betaine through threefold methylation. Exogenous sarcosine (1 mM) effectively suppressed the intracellular accumulation of betaine, and a higher level of sarcosine accumulation was accompanied by a lower level of betaine synthesis. Exogenous dimethylglycine has an effect similar to that of betaine addition, which increased the intracellular pool of betaine and suppressed the levels of Nepsilon-acetyl-beta-lysine and beta-glutamine. Both in vivo and in vitro betaine formation assays with glycine as the substrate showed only sarcosine and betaine, but no dimethylglycine. Dimethylglycine was detected only when it was added as a substrate in in vitro assays. A high level of potassium (400 mM and above) was necessary for betaine formation in vitro. Interestingly, no methylamines were detected without the addition of KCl. Also, high levels of NaCl and LiCl (800 mM) favored sarcosine accumulation, while a lower level (400 mM) favored betaine synthesis. The above observations indicate that a high sarcosine level suppressed multiple methylation while dimethylglycine was rapidly converted to betaine. Also, high levels of potassium led to greater amounts of betaine, while lower levels of potassium led to greater amounts of sarcosine. This finding suggests that the intracellular levels of both sarcosine and potassium are associated with the regulation of betaine synthesis in M. portucalensis.
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Affiliation(s)
- M C Lai
- Department of Botany, National Chung-Hsing University, Taichung, Taiwan, Republic of China.
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Wiggins PM, Rowlandson J, Ferguson AB. Preservation of murine embryos in a state of dormancy at 4 degreesC. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:C291-9. [PMID: 9950755 DOI: 10.1152/ajpcell.1999.276.2.c291] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
With the aim of improving preservation of blood products and organs for transplantation, we designed solutions to induce a state of dormancy in cells and tissues at 4 degreesC. The solutions were devoid of combinations of ions (e.g., K+, Rb+, Cs+, and NH+4 with HCO-3, H2PO-4, and Cl-) that are believed to break down low-density water in the entrance compartments of ion channels, resulting in cyclical open states (normal water) and closed states (low-density water). The total osmolality was always 0.29-0.3 osmol/kgH2O, made up of combinations of a di- or trisaccharide, a compatible solute, sodium sulfate, citrate, or chloride, and 1.75 mM CaCl2. The end point was the ability of murine embryos to progress to hatching in culture after preservation in such a solution at 4 degreesC. Embryos hatched after 5 or 6 days in some preservative solutions compared with 1-3 days in most saline solutions; survival was improved by pretreatment with sodium butyrate.
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Affiliation(s)
- P M Wiggins
- Department of Medicine, University of Auckland School of Medicine, Auckland 1003, New Zealand
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Lang F, Busch GL, Ritter M, Völkl H, Waldegger S, Gulbins E, Häussinger D. Functional significance of cell volume regulatory mechanisms. Physiol Rev 1998; 78:247-306. [PMID: 9457175 DOI: 10.1152/physrev.1998.78.1.247] [Citation(s) in RCA: 1267] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To survive, cells have to avoid excessive alterations of cell volume that jeopardize structural integrity and constancy of intracellular milieu. The function of cellular proteins seems specifically sensitive to dilution and concentration, determining the extent of macromolecular crowding. Even at constant extracellular osmolarity, volume constancy of any mammalian cell is permanently challenged by transport of osmotically active substances across the cell membrane and formation or disappearance of cellular osmolarity by metabolism. Thus cell volume constancy requires the continued operation of cell volume regulatory mechanisms, including ion transport across the cell membrane as well as accumulation or disposal of organic osmolytes and metabolites. The various cell volume regulatory mechanisms are triggered by a multitude of intracellular signaling events including alterations of cell membrane potential and of intracellular ion composition, various second messenger cascades, phosphorylation of diverse target proteins, and altered gene expression. Hormones and mediators have been shown to exploit the volume regulatory machinery to exert their effects. Thus cell volume may be considered a second message in the transmission of hormonal signals. Accordingly, alterations of cell volume and volume regulatory mechanisms participate in a wide variety of cellular functions including epithelial transport, metabolism, excitation, hormone release, migration, cell proliferation, and cell death.
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Affiliation(s)
- F Lang
- Institute of Physiology, University of Tübingen, Germany
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Gilles R. "Compensatory" organic osmolytes in high osmolarity and dehydration stresses: history and perspectives. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART A, PHYSIOLOGY 1997; 117:279-90. [PMID: 9172384 DOI: 10.1016/s0300-9629(96)00265-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
As stated in the conclusion, "life is a thing of macromolecular cohesion in salty water." This brief historical overview shows that "compensatory" organic osmolytes take an essential place in this cohesion. It reviews the major steps of the study of these compounds over more than 100 years, from the early beginnings of 1885 until now, showing some of its fascinating developments and ending on the idea that the most fascinating is still to come. This study can be taken as an example of the richness of the comparative approach.
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Affiliation(s)
- R Gilles
- Laboratory of Animal Physiology, University of Liège, Belgium
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Galinski EA, Stein M, Amendt B, Kinder M. The Kosmotropic (Structure-Forming) Effect of Compensatory Solutes. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0300-9629(96)00275-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ferrer-Martinez A, Casado FJ, Felipe A, Pastor-Anglada M. Regulation of Na+,K(+)-ATPase and the Na+/K+/Cl- co-transporter in the renal epithelial cell line NBL-1 under osmotic stress. Biochem J 1996; 319 ( Pt 2):337-42. [PMID: 8912665 PMCID: PMC1217774 DOI: 10.1042/bj3190337] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The long-term adaptation of the Na+,K(+)-ATPase to hypertonicity was studied using the bovine renal epithelial cell line NBL-1. Na+,K(+)-ATPase activity measured in intact cells as the ouabain-sensitive fraction of Rb+ uptake was stimulated (40% above controls) after incubating the cells in hypertonic medium. This stimulation was not correlated with significant changes in the amount of Na+,K(+)-ATPase alpha 1 subunit protein. Nevertheless, the amount of alpha 1 but not beta 1 subunit mRNA progressively increased after hypertonic shock (3-4-fold above basal values). These results suggest that the alpha 1 subunit gene is modulated by medium osmolarity, although this does not necessarily involve enhanced translation of the mRNA into active alpha 1 protein. Indeed, the increase in the biological activity of the Na+,K(+)-ATPase is abolished when the electrochemical Na+ transmembrane gradient is depleted by monensin, which is consistent with a post-translational effect on the activity of the sodium pump. A furosemide-sensitive component of Rb+ uptake, attributable to Na+/K+/Cl- co-transporter activity, was very low when cells were cultured in a regular medium, but was greatly induced after hypertonic shock. This induction could not be blocked by cycloheximide. Colcemide addition slightly reduced the absolute increase in Na+/K+/Cl- co-transporter activity, while cytochalasin B significantly potentiated the effect triggered by hypertonic shock. It is concluded: (i) that in NBL-1 cells the alpha 1 but not the beta 1 subunit of the Na+,K(+)-ATPase is encoded by an osmotically sensitive gene, and (ii) that the Na+/K+/Cl- co-transporter, although an osmotically sensitive carrier, is induced by a mechanism that is independent of protein synthesis but may rely, in an undetermined manner, on the structure of the cytoskeletal network.
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Affiliation(s)
- A Ferrer-Martinez
- Department de Bioquímica i Biologia Molecular, Universitat de Barcelona, Spain
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Hall JA, Kirk J, Potts JR, Rae C, Kirk K. Anion channel blockers inhibit swelling-activated anion, cation, and nonelectrolyte transport in HeLa cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:C579-88. [PMID: 8769998 DOI: 10.1152/ajpcell.1996.271.2.c579] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of osmotic cell swelling on the permeability of HeLa cells to a range of structurally unrelated solutes including taurine, sorbitol, thymidine, choline, and K+ (96Rb+) was investigated. For each solute tested, reduction in the osmolality of the medium from 300 to 200 mosmol/kgH2O caused a significant increase in the unidirectional influx rate. In each case, the osmotically activated transport component was nonsaturable up to external substrate concentrations of 50 mM. Inhibitors of the swelling-activated anion channel of HeLa cells [quinine, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, niflumate, 1,9-dideoxyforskolin, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), and tamoxifen] blocked the osmotically activated influx of each of the different substrates tested, as well as the osmotically activated efflux of taurine and I-. Tamoxifen and NPPB were similarly effective at blocking the osmotically activated efflux of 96Rb+. The simplest of several hypotheses consistent with the data is that the osmotically activated transport of the different solutes tested here is via a swelling-activated anion-selective channel that has a significant cation permeability and a minimum pore diameter of 8-9 A.
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Affiliation(s)
- J A Hall
- University Laboratory of Physiology, Oxford, United Kingdom
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Vieyra A. Catalytic and structural modifications of sarcoplasmic reticulum and plasma membrane (Ca(2+) + Mg2+) ATPases induced by organic solutes that accumulate in living systems. Biosci Rep 1996; 16:115-27. [PMID: 8790917 DOI: 10.1007/bf01206201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Organic solutes such as urea, methylamines, polyols and amino acid can accumulate in the cytoplasm of cells to compensate for hyperosmotic conditions in the external medium. Whereas urea is considered to be typical of solutes that destabilize structure and function of proteins, methylamines, polyols and some amino acids appear to have the opposite effect, and can also compensate for the perturbing effects of urea. These effects have been extensively analyzed for a variety of proteins in terms of global changes in enzyme structure and acceleration or inhibition of overall reaction rates. Here the influence of these solutes on sarcoplasmic reticulum and plasma membrane (Ca(2+) + Mg2+) ATPases is reviewed. The focus is on the changes induced by "perturbing" and "stabilizing" solutes at specific steps of the catalytic cycles of these enzymes, which can run forward (leading to ATP hydrolysis) and backward (leading to ATP synthesis). Structural changes promoted by osmolytes are correlated with functional changes, especially those that are related to energy coupling.
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Affiliation(s)
- A Vieyra
- Departamento de Bioquimica Medica, Universidade Federal de Rio de Janeiro, Brazil
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Flögel U, Niendorf T, Serkowa N, Brand A, Henke J, Leibfritz D. Changes in organic solutes, volume, energy state, and metabolism associated with osmotic stress in a glial cell line: a multinuclear NMR study. Neurochem Res 1995; 20:793-802. [PMID: 7477672 DOI: 10.1007/bf00969691] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Diffusion-weighted in vivo 1H-NMR spectroscopy of F98 glioma cells embedded in basement membrane gel threads showed that the initial cell swelling to about 180% of the original volume induced under hypotonic stress was followed by a regulatory volume decrease to nearly 100% of the control volume in Dulbecco's modified Eagle's medium (DMEM) but only to 130% in Krebs-Henseleit buffer (KHB, containing only glucose as a substrate) after 7 h. The initial cell shrinkage to approx. 70% induced by the hypertonic stress was compensated by a regulatory volume increase which after 7 h reached almost 100% of the control value in KHB and 75% in DMEM. 1H-, 13C- and 31P-NMR spectroscopy of perchloric acid extracts showed that these volume regulatory processes were accompanied by pronounced changes in the content of organic osmolytes. Adaptation of intra- to extracellular osmolarity was preferentially mediated by a decrease in the cytosolic taurine level under hypotonic stress and by an intracellular accumulation of amino acids under hypertonic stress. If these solutes were not available in sufficient quantities (as in KHB), the osmolarity of the cytosol was increasingly modified by biosynthesis of products and intermediates of essential metabolic pathways, such as alanine, glutamate and glycerophosphocholine in addition to ethanolamine. The cellular nucleoside triphosphate level measured by in vivo 31P-NMR spectroscopy indicated that the energy state of the cells was more easily sustained under hypotonic than hypertonic conditions.
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Affiliation(s)
- U Flögel
- Institut für Organische Chemie, Universität Bremen, Germany
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