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Li M, Wang S, Kang L, Xu F, Lan X, He M, Jin K, Xia Y. Arginine metabolism governs microcycle conidiation by changing nitric oxide content in Metarhizium acridum. Appl Microbiol Biotechnol 2023; 107:1257-1268. [PMID: 36640205 DOI: 10.1007/s00253-022-12355-6] [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: 11/09/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 01/15/2023]
Abstract
Microcycle conidiation commonly exists in filamentous fungi and has great potential for mass production of mycoinsecticides. L-Arginine metabolism is essential for conidiation and conditional growth and virulence, but its role in microcycle conidiation has not been explored. Here, a unique putative arginase (MaAGA) was characterized in the entomopathogenic fungus Metarhizium acridum. Conidial germination and thermotolerance were facilitated by the disruption of MaAGA. Despite little impact on fungal growth and virulence, the disruption resulted in normal conidiation after a 60-h incubation on microcycle conidiation medium (SYA) under normal culture conditions. In the MaAGA-disruption mutant (ΔMaAGA), intracellular arginine accumulation was sharply increased. Replenishment of the direct metabolites of arginase, namely ornithine and/or urea, was unable to restore the disruption mutant's microcycle conidiation on SYA. Interestingly, nitric oxide synthase (NOS) activity and nitric oxide (NO) levels of the ΔMaAGA strain were markedly decreased in the 60-h-old SYA cultures. Finally, adding Nω-nitro-L-arginine, an inhibitor of NOS, into the SYA converted the microcycle conidiation of the wild-type strain to normal conidiation. In contrast, adding sodium nitroprusside, an NO donor, into the SYA recovered the mutant's microcycle conidiation. The results indicate that arginine metabolism controls microcycle conidiation by changing the content of NO. KEY POINTS: • The MaAGA-disruption led to normal conidiation on microcycle conidiation medium SYA. • Nitric oxide (NO) level of the ΔMaAGA strain was markedly decreased. • Adding an NO donor into the SYA recovered the microcycle conidiation of ΔMaAGA.
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Affiliation(s)
- Mengfei Li
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Shuqin Wang
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Luhong Kang
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Fei Xu
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Xia Lan
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Min He
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China.,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China
| | - Kai Jin
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China. .,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China. .,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China.
| | - Yuxian Xia
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 401331, People's Republic of China. .,Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, 401331, People's Republic of China. .,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, 401331, Chongqing, People's Republic of China.
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Volkov V. Quantitative description of ion transport via plasma membrane of yeast and small cells. FRONTIERS IN PLANT SCIENCE 2015; 6:425. [PMID: 26113853 PMCID: PMC4462678 DOI: 10.3389/fpls.2015.00425] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/26/2015] [Indexed: 05/21/2023]
Abstract
Modeling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterization of main ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and determining the exact number of molecules of each transporter per a typical cell allow us to predict the corresponding ion flows. In this review a comparison of ion transport in small yeast cell and several animal cell types is provided. The importance of cell volume to surface ratio is emphasized. The role of cell wall and lipid rafts is discussed in respect to required increase in spatial and temporary resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.
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Affiliation(s)
- Vadim Volkov
- *Correspondence: Vadim Volkov, Faculty of Life Sciences, School of Human Sciences, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK
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Gros P, Talbot F, Tang-Wai D, Bibi E, Kaback HR. Lipophilic cations: a group of model substrates for the multidrug-resistance transporter. Biochemistry 2002; 31:1992-8. [PMID: 1371401 DOI: 10.1021/bi00122a014] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The possibility that simple lipophilic cations such as tetraphenylphosphonium (TPA+), triphenylmethylphosphonium (TPMP+), and diphenyldimethylphosphonium (DDP+) are substrates for the multidrug-resistance transport protein, P-glycoprotein, was tested. Hamster cells transfected with and overexpressing mouse mdr1 or mouse mdr3 exhibit high levels of resistance to TPP+ and TPA+ (20-fold) and somewhat lower levels of resistance to TPMP+ and DDP+ (3-12-fold). Transfected cell clones expressing mdr1 or mdr3 mutants with decreased activity against drugs of the MDR spectrum (e.g., Vinca alkaloids and anthracyclines) also show reduced resistance to lipophilic cations. Studies with radiolabeled TPP+ and TPA+ demonstrate that increased resistance to cytotoxic concentrations of these lipophilic cations is correlated quantitatively with a decrease in intracellular accumulation in mdr1- and mdr3-transfected cells. This decreased intracellular accumulation is shown to be strictly dependent on intact intracellular nucleotide triphosphate pools and is reversed by verapamil, a known competitive inhibitor of P-glycoprotein. Taken together, these results demonstrate that lipophilic cations are a new class of substrates for P-glycoprotein and can be used to study its mechanism of action in homologous and heterologous systems.
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Affiliation(s)
- P Gros
- Department of Biochemistry, McGill University, Montreal, Canada
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Eddy AA, Hopkins P. Cytosine accumulation as a measure of the proton electrochemical gradient acting on the overexpressed cytosine permease of Saccharomyces cerevisiae. MICROBIOLOGY (READING, ENGLAND) 1996; 142 ( Pt 3):449-457. [PMID: 8868419 DOI: 10.1099/13500872-142-3-449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The magnitude of the proton gradient (delta mu H+) driving solute accumulation in Saccharomyces cerevisiae has long been in doubt, principally because of the lack of an agreed method for assaying its electrical component, the membrane potential (delta psi). In the present work, the size of the cytosine gradient (delta mu cyt) that the yeast generated was used as a measure of the driving gradient (delta mu H+). The selected yeast lacked cytosine deaminase and overexpressed cytosine permease, a 1 H+/cytosine system. delta mu cyt, assayed in washed cell suspensions fermenting glucose and containing 0.5 or 50 mM KCl, was about 260 mV at pH 4 or 5, falling to about 194 mV at pH 7. As a first estimate, -delta mu H+ was thus at least as large at the respective pH value. A 20 mM solution of the lipophilic cation tetraphenylphosphonium lowered delta mu cyt to a value roughly equal to the magnitude of the pH gradient (delta pH). A mathematical model was used to correct the first estimates of delta mu H+ for the effect of cytosine leakage outside the symport. In such a system, delta mu cyt cannot exceed the equivalent ratio Vmax/KmL, where Vmax and Km are kinetic parameters of the symport and L is the rate coefficient for leakage. The feasibility of assaying delta mu H+ depends on it not being much larger than that ratio. The model was tested successfully against observations made with yeast preparations depleted of ATP. After correction, -delta mu H+ during fermentation was estimated to be up to 25 mV larger than delta mu cyt and at least 70 mV larger than previous estimates in the literature involving lipophilic cations. From a knowledge of delta pH, delta psi was in turn deduced and compared with the maximum methylamine gradient (delta mu M) the yeast formed. The results supported the claim in the literature that, at acid pH, delta mu M is a measure of delta psi.
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Affiliation(s)
- A A Eddy
- Department of Biochemistry and Applied Molecular Biology, University of Manchester Institute of Science and Technology, PO Box 88, Manchester M60 1QD, UK
| | - P Hopkins
- Department of Biochemistry and Applied Molecular Biology, University of Manchester Institute of Science and Technology, PO Box 88, Manchester M60 1QD, UK
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Ballarin-Denti A, Slayman CL, Kuroda H. Small lipid-soluble cations are not membrane voltage probes for Neurospora or Saccharomyces. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1190:43-56. [PMID: 8110820 DOI: 10.1016/0005-2736(94)90033-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Small lipid-soluble cations, such as tetraphenylphosphonium (TPP+) and tetraphenylarsonium (TPA+) are frequently used as probes of membrane voltage (delta psi, or Vm) for small animal cells, organelles, and vesicles. Because much controversy has accompanied corresponding measurements on 'walled' eukaryotic cells (plants, fungi), we studied their transport and relation to Vm in the large-celled fungus Neurospora crassa-where Vm can readily be determined with microelectrodes-as well as in the most commonly used model eukaryotic cell, the yeast Saccharomyces cerevisiae. We found no reasonable conditions under which the distribution of TPP+ or TPA+, between the cytoplasm (i) and extracellular solution (o), can serve to estimate Vm, even roughly, in either of these organisms. When applied at probe concentrations (i.e., < or = 100 microM, which did not depolarize the cells nor deplete ATP), TPP+ stabilized at ratios (i/o) below 30 in both organisms. That would imply apparent Vm values positive to -90 mV, in the face of directly measured Vm values (in Neurospora) negative to -180 mV. When applied at moderate or high concentrations (1-30 mM), TPP+ and TPA+ induced several phases of depolarization and changes of membrane resistance (Rm), as well as depletion of cytoplasmic energy stores. Only the first phase depolarization, occurring within the perfusion-turnover time and accompanied by a nearly proportionate decline of Rm, could have resulted from TPP+ or TPA+ currents per se. And the implied currents were small. Repeated testing, furthermore, greatly reduced the depolarizing effects of these lipid-soluble ions, implicating an active cellular response to decrease membrane permeability.
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Affiliation(s)
- A Ballarin-Denti
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510
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Vallejo CG, Serrano R. Physiology of mutants with reduced expression of plasma membrane H+-ATPase. Yeast 1989; 5:307-19. [PMID: 2528864 DOI: 10.1002/yea.320050411] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Two mutations containing insertions and deletions in the promoter in the plasma membrane H+-ATPase gene (PMA1) of Saccharomyces cerevisiae have been introduced into the genome by homologous recombination, replacing the wild-type gene. The resulting strains have 15 and 23% of the wild-type ATPase content. Decreased levels of ATPase correlate with decreased rates of proton efflux and decreased uptake rates of amino acids, methylamine, hygromycin B and tetraphenylphosphonium. This supports a central role of the enzyme in yeast bioenergetics. However, the final accumulation gradient of tetraphenylphosphonium is not affected by the mutations and that of methylamine and 2-aminoisobutyric acid is only decreased in the most extreme mutant. Apparently, kinetic constraints seem to prevent the equilibration of yeast active transports with the electrochemical proton gradient. As expected from their transport defects, the ATPase-deficient mutants are more resistant to hygromycin B and more sensitive to acidification than wild-type yeast. Mutant cells are very elongated, suggesting a structural role of the ATPase in the yeast surface.
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Affiliation(s)
- C G Vallejo
- European Molecular Biology Laboratory, Heidelberg, Germany
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Van Duijn B, Ypey DL, Van der Molen LG. Electrophysiological properties of Dictyostelium derived from membrane potential measurements with microelectrodes. J Membr Biol 1988; 106:123-34. [PMID: 3225840 DOI: 10.1007/bf01871394] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Electrical membrane properties of the cellular slime mold Dictyostelium discoideum were investigated with the use of intracellular microelectrodes. The rapid potential transients (1 msec) upon microelectrode penetration of normal cells had a negative-going peak-shaped time course. This indicates that penetration of a cell with a microelectrode causes a rapid depolarization, which can just be recorded by the microelectrode itself. Therefore, the initial (negative) peak potential transient value Ep (-19mV) should be used as an indicator of the resting membrane potential Em of D. discoideum before impalement, rather than the subsequent semistationary depolarized value En (-5 mV). Using enlarged cells such as giant mutant cells (Ep = -39 mV) and electrofused normal cells (Ep = -30 mV) improved the reliability of Ep as an indicator of Em. From the data we concluded that Em of D. discoideum cells bathed in (mM) 40 NaCl, 5 KCl and 1 CaCl2 is at least -50 mV. This potential was shown to be dependent on extracellular potassium. The average input resistance Ri of the impaled cells was 56 M omega for normal D. discoideum. However, our analysis indicates that the membrane resistance of these cells before impalement is greater than 1 G omega. Specific membrane capacitance was 1-3 pF/cm2. Long-term recording of the membrane potential showed the existence of a transient hyperpolarization following the rapid impalement transient. This hyperpolarization was associated with an increase in Ri of the impaled cell. It was followed by a depolarization, which was associated with a decrease in Ri. The depolarization time was dependent on the filling of the microelectrode. The present characterization of the electrical membrane properties of Dictyostelium cells is a first step in a membrane electrophysiological analysis of signal transduction in cellular slime molds.
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Affiliation(s)
- B Van Duijn
- Cell Biology and Genetics Unit, University of Leiden, The Netherlands
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