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Jacobus AP, Cavassana SD, de Oliveira II, Barreto JA, Rohwedder E, Frazzon J, Basso TP, Basso LC, Gross J. Optimal trade-off between boosted tolerance and growth fitness during adaptive evolution of yeast to ethanol shocks. Biotechnol Biofuels Bioprod 2024; 17:63. [PMID: 38730312 PMCID: PMC11088041 DOI: 10.1186/s13068-024-02503-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/05/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND The selection of Saccharomyces cerevisiae strains with higher alcohol tolerance can potentially increase the industrial production of ethanol fuel. However, the design of selection protocols to obtain bioethanol yeasts with higher alcohol tolerance poses the challenge of improving industrial strains that are already robust to high ethanol levels. Furthermore, yeasts subjected to mutagenesis and selection, or laboratory evolution, often present adaptation trade-offs wherein higher stress tolerance is attained at the expense of growth and fermentation performance. Although these undesirable side effects are often associated with acute selection regimes, the utility of using harsh ethanol treatments to obtain robust ethanologenic yeasts still has not been fully investigated. RESULTS We conducted an adaptive laboratory evolution by challenging four populations (P1-P4) of the Brazilian bioethanol yeast, Saccharomyces cerevisiae PE-2_H4, through 68-82 cycles of 2-h ethanol shocks (19-30% v/v) and outgrowths. Colonies isolated from the final evolved populations (P1c-P4c) were subjected to whole-genome sequencing, revealing mutations in genes enriched for the cAMP/PKA and trehalose degradation pathways. Fitness analyses of the isolated clones P1c-P3c and reverse-engineered strains demonstrated that mutations were primarily selected for cell viability under ethanol stress, at the cost of decreased growth rates in cultures with or without ethanol. Under this selection regime for stress survival, the population P4 evolved a protective snowflake phenotype resulting from BUD3 disruption. Despite marked adaptation trade-offs, the combination of reverse-engineered mutations cyr1A1474T/usv1Δ conferred 5.46% higher fitness than the parental PE-2_H4 for propagation in 8% (v/v) ethanol, with only a 1.07% fitness cost in a culture medium without alcohol. The cyr1A1474T/usv1Δ strain and evolved P1c displayed robust fermentations of sugarcane molasses using cell recycling and sulfuric acid treatments, mimicking Brazilian bioethanol production. CONCLUSIONS Our study combined genomic, mutational, and fitness analyses to understand the genetic underpinnings of yeast evolution to ethanol shocks. Although fitness analyses revealed that most evolved mutations impose a cost for cell propagation, combination of key mutations cyr1A1474T/usv1Δ endowed yeasts with higher tolerance for growth in the presence of ethanol. Moreover, alleles selected for acute stress survival comprising the P1c genotype conferred stress tolerance and optimal performance under conditions simulating the Brazilian industrial ethanol production.
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Affiliation(s)
- Ana Paula Jacobus
- Bioenergy Research Institute, São Paulo State University, Rio Claro, Brazil
- SENAI Innovation Institute for Biotechnology, São Paulo, Brazil
| | | | | | | | - Ewerton Rohwedder
- Biological Science Department, "Luiz de Queiroz" College of Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Jeverson Frazzon
- Institute of Food Science and Technology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Thalita Peixoto Basso
- Department of Agri-Food Industry, Food and Nutrition, "Luiz de Queiroz" College of Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Luiz Carlos Basso
- Biological Science Department, "Luiz de Queiroz" College of Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Jeferson Gross
- Bioenergy Research Institute, São Paulo State University, Rio Claro, Brazil.
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Abe MM, Branciforti MC, Nallin Montagnolli R, Marin Morales MA, Jacobus AP, Brienzo M. Production and assessment of the biodegradation and ecotoxicity of xylan- and starch-based bioplastics. Chemosphere 2022; 287:132290. [PMID: 34562707 DOI: 10.1016/j.chemosphere.2021.132290] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
Developing novel renewable (and preferably biodegradable) materials has become recurrent due to the growing concerns with environmental impacts of high volumes of plastic waste produced from oil-based sources over the past decades. This study aimed at developing bioplastics from a mixture of starch and xylan in variable ratios, and the combined effect of α-cellulose and holocellulose extracted from sugarcane bagasse added to the process. The disintegration of bioplastics was evaluated in both soil and composting. The ecotoxicity analyses with Saccharomyces cerevisiae, Bacillus subtilis and seeds of Cucumis sativus were conducted after disintegration. All formulations based on 5% (w/v) of total polysaccharides were dried at 30 °C and resulted in homogeneous and non-brittle bioplastics. The composting results showed that all bioplastic formulations disintegrated in 3 days, whereas the 25/75% (xylan/starch, w/w) formulation vanished in soil within 13 days. The ecotoxicity data showed no inhibition of microbial growth after biodegradation, yielding 100% of seed germination. Despite the positive influence of the bioplastic degradation on the root and hypocotyl growth, temporary inhibition of C. sativus tissues exposed to soil washing (10 days of disintegration) was observed. The study demonstrated that xylan/starch bioplastics result in non-ecotoxic biodegradable materials.
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Affiliation(s)
- Mateus Manabu Abe
- Institute for Research in Bioenergy (IPBEN), University of São Paulo State (UNESP), Rio Claro, SP, 13500-230, Brazil
| | - Marcia Cristina Branciforti
- Department of Materials Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Carlos, 13566-590, Brazil
| | - Renato Nallin Montagnolli
- Department of Natural Sciences, Mathematics and Education, Agricultural Sciences Centre- Federal University of São Carlos (UFSCar), SP-330, km 174, Araras, SP, Brazil
| | - Maria Aparecida Marin Morales
- Department of Biology, Institute of Biosciences, University of São Paulo State (UNESP), Av. 24-A, 1515, CP 199, Rio Claro, SP, 13506-900, Brazil
| | - Ana Paula Jacobus
- Institute for Research in Bioenergy (IPBEN), University of São Paulo State (UNESP), Rio Claro, SP, 13500-230, Brazil
| | - Michel Brienzo
- Institute for Research in Bioenergy (IPBEN), University of São Paulo State (UNESP), Rio Claro, SP, 13500-230, Brazil.
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Jacobus AP, Stephens TG, Youssef P, González-Pech R, Ciccotosto-Camp MM, Dougan KE, Chen Y, Basso LC, Frazzon J, Chan CX, Gross J. Comparative Genomics Supports That Brazilian Bioethanol Saccharomyces cerevisiae Comprise a Unified Group of Domesticated Strains Related to Cachaça Spirit Yeasts. Front Microbiol 2021; 12:644089. [PMID: 33936002 PMCID: PMC8082247 DOI: 10.3389/fmicb.2021.644089] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 03/08/2021] [Indexed: 01/05/2023] Open
Abstract
Ethanol production from sugarcane is a key renewable fuel industry in Brazil. Major drivers of this alcoholic fermentation are Saccharomyces cerevisiae strains that originally were contaminants to the system and yet prevail in the industrial process. Here we present newly sequenced genomes (using Illumina short-read and PacBio long-read data) of two monosporic isolates (H3 and H4) of the S. cerevisiae PE-2, a predominant bioethanol strain in Brazil. The assembled genomes of H3 and H4, together with 42 draft genomes of sugarcane-fermenting (fuel ethanol plus cachaça) strains, were compared against those of the reference S288C and diverse S. cerevisiae. All genomes of bioethanol yeasts have amplified SNO2(3)/SNZ2(3) gene clusters for vitamin B1/B6 biosynthesis, and display ubiquitous presence of a particular family of SAM-dependent methyl transferases, rare in S. cerevisiae. Widespread amplifications of quinone oxidoreductases YCR102C/YLR460C/YNL134C, and the structural or punctual variations among aquaporins and components of the iron homeostasis system, likely represent adaptations to industrial fermentation. Interesting is the pervasive presence among the bioethanol/cachaça strains of a five-gene cluster (Region B) that is a known phylogenetic signature of European wine yeasts. Combining genomes of H3, H4, and 195 yeast strains, we comprehensively assessed whole-genome phylogeny of these taxa using an alignment-free approach. The 197-genome phylogeny substantiates that bioethanol yeasts are monophyletic and closely related to the cachaça and wine strains. Our results support the hypothesis that biofuel-producing yeasts in Brazil may have been co-opted from a pool of yeasts that were pre-adapted to alcoholic fermentation of sugarcane for the distillation of cachaça spirit, which historically is a much older industry than the large-scale fuel ethanol production.
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Affiliation(s)
- Ana Paula Jacobus
- Laboratory for Genomics and Experimental Evolution of Yeasts, Institute for Bioenergy Research, São Paulo State University, Rio Claro, Brazil
| | - Timothy G Stephens
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Pierre Youssef
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Raul González-Pech
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Michael M Ciccotosto-Camp
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Katherine E Dougan
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Yibi Chen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Luiz Carlos Basso
- Biological Science Department, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo (USP), Piracicaba, Brazil
| | - Jeverson Frazzon
- Institute of Food Science and Technology, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Jeferson Gross
- Laboratory for Genomics and Experimental Evolution of Yeasts, Institute for Bioenergy Research, São Paulo State University, Rio Claro, Brazil
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Pieta L, Escudero FLG, Jacobus AP, Cheiran KP, Gross J, Moya MLE, Soares GLG, Margis R, Frazzon APG, Frazzon J. Comparative transcriptomic analysis of Listeria monocytogenes reveals upregulation of stress genes and downregulation of virulence genes in response to essential oil extracted from Baccharis psiadioides. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1277-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Escott GM, de Castro AL, Jacobus AP, Loss ES. Insulin and IGF-I actions on IGF-I receptor in seminiferous tubules from immature rats. Biochim Biophys Acta 2014; 1838:1332-7. [PMID: 24530896 DOI: 10.1016/j.bbamem.2014.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/14/2014] [Accepted: 02/01/2014] [Indexed: 11/17/2022]
Abstract
Insulin and insulin-like growth factor 1 (IGF-I) are capable of activating similar intracellular pathways. Insulin acts mainly through its own receptor, but can also activate the IGF-I receptor (IGF-IR). The aim of this study was to investigate the involvement of the IGF-IR in the effects of insulin and IGF-I on the membrane potential of immature Sertoli cells in whole seminiferous tubules, as well as on calcium, amino acid, and glucose uptake in testicular tissue of immature rats. The membrane potential of the Sertoli cells was recorded using a standard single microelectrode technique. In calcium uptake experiments, the testes were pre-incubated with (45)Ca(2+), with or without JB1 (1 μg/mL), and then incubated with insulin (100 nM) or IGF-I (15 nM). In amino acid and glucose uptake experiments, the gonads were pre-incubated with or without JB1 (1 μg/mL) and then incubated with radiolabeled amino acid or glucose analogues in the presence of insulin (100 nM) or IGF-I (15 nM). The blockade of IGF-IR with JB1 prevented the depolarising effects of both insulin and IGF-I on membrane potential, as well as the effect of insulin on calcium uptake. JB1 also inhibited the effects of insulin and IGF-I on glucose uptake. The effect of IGF-I on amino acid transport was inhibited in the presence of JB1, whereas the effect of insulin was not. We concluded that while IGF-I seems to act mainly through its cognate receptor to induce membrane depolarisation and calcium, amino acid and glucose uptake, insulin appears to be able to elicit its effects through IGF-IR, in seminiferous tubules from immature rats.
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Affiliation(s)
- Gustavo Monteiro Escott
- Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil
| | - Alexandre Luz de Castro
- Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil
| | | | - E S Loss
- Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.
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Escott GM, Jacobus AP, Loss ES. PI3K-dependent actions of insulin and IGF-I on seminiferous tubules from immature rats. Pflugers Arch 2013; 465:1497-505. [DOI: 10.1007/s00424-013-1287-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/09/2013] [Accepted: 04/19/2013] [Indexed: 12/21/2022]
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Loss ES, Jacobus AP, Wassermann GF. Rapid signaling responses in Sertoli cell membranes induced by follicle stimulating hormone and testosterone: calcium inflow and electrophysiological changes. Life Sci 2011; 89:577-83. [PMID: 21703282 DOI: 10.1016/j.lfs.2011.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 05/04/2011] [Accepted: 05/25/2011] [Indexed: 10/18/2022]
Abstract
This minireview describes the rapid signaling actions of follicle stimulating hormone (FSH) and testosterone in immature Sertoli cells mainly related to Ca(2+) inflow and the electrophysiological changes produced by hormones. The rapid membrane actions of FSH occur in a time frame of seconds to minutes, which include membrane depolarization and the stimulation of (45)Ca(2+) uptake. These effects can be prevented by pertussis toxin (PTX), suggesting that they are likely mediated by Gi-protein coupled receptor activation. Furthermore, these effects were inhibited by verapamil, a blocker of the L-type voltage-dependent Ca(2+) channel (VDCC). Finally, FSH stimulation of (45)Ca(2+) uptake was inhibited by the (phosphoinositide 3-kinase) PI3K inhibitor wortmannin. These results suggest that the rapid action of FSH on L-type Ca(2+) channel activity in Sertoli cells from pre-pubertal rats is mediated by the Gi/Gβγ/PI3Kγ pathway, independent of its effects on insulin-like growth factor type I (IGF-I). Testosterone depolarizes the membrane potential and increases the resistance and the (45)Ca(2+) uptake in Sertoli cells of the seminiferous tubules of immature rats. These actions were nullified by diazoxide (K(+)(ATP) channel opener). Testosterone actions were blocked by both PTX and the phospholipase C (PLC) inhibitor U73122, suggesting the involvement of PLC - phosphatidylinositol 4-5 bisphosphate (PIP2) hydrolysis via the Gq protein in the testosterone-mediated pathway. These results indicate that testosterone acts on the Sertoli cell membrane through the K(+)(ATP) channels and PLC-PIP2 hydrolysis, which closes the channel, depolarizes the membrane and stimulates (45)Ca(2+) uptake. These results demonstrate the existence of rapid non-classical pathways in immature Sertoli cells regulated by FSH and testosterone.
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Affiliation(s)
- Eloísa S Loss
- Laboratório de Endocrinologia Experimental e Eletrofisiologia Endócrina Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite 500, Porto Alegre/RS, Brazil
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Jacobus AP, Loss ES, Wassermann GF. Pertussis toxin nullifies the depolarization of the membrane potential and the stimulation of the rapid phase of Ca entry through L-type calcium channels that are produced by follicle stimulating hormone in 10- to 12-day-old rat Sertoli cells. Front Physiol 2010; 1:138. [PMID: 21423378 PMCID: PMC3059968 DOI: 10.3389/fphys.2010.00138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 09/15/2010] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the effect of pertussis toxin (PTX) on the depolarizing component of the action of follicle stimulating hormone (FSH) on the membrane potential (MP) of Sertoli cells, which is linked to the rapid entry of Ca2+ into cells and to the Ca2+-dependent transport of neutral amino acids by the A system. This model allowed us to analyze the involvement of Gi proteins in the action of FSH in these phenomena. In parallel, using an inactive analog of insulin-like growth factor type I (IGF-1), JB1, and an anti-IGF-I antibody we investigated the possible mediating role of IGF-I on these effects of FSH because IGF-I is produced and released by testicular cells in response to stimulation by FSH and shows depolarization effects on MP similar to those from FSH. Our results have the following implications: (a) the rapid membrane actions of FSH, which occur in a time-frame of seconds to minutes and include the depolarization of the MP, and stimulation of 45Ca2+ uptake and [14C]-methyl aminoisobutyric acid ([14C]-MeAIB) transport, are nullified by the action of PTX and, therefore, are probably mediated by GiPCR activation; (b) the effects of FSH were also nullified by verapamil, an L-type voltage-dependent Ca2+ channel blocker; (c) wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), prevented FSH stimulation of 45Ca2+ entry and [14C]-MeAIB transport; and (d) these FSH actions are independent of the IGF-I effects. In conclusion, these results strongly suggest that the rapid action of FSH on L-type Ca2+ channel activity in Sertoli cells from 10- to 12-day-old rats is mediated by the Gi/βγ/PI3Kγ pathway, independent of the effects of IGF-I.
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Affiliation(s)
- Ana Paula Jacobus
- Laboratório de Endocrinologia Experimental e Eletrofisiologia Endócrina, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul Porto Alegre, Rio Grande do Sul, Brazil
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Abstract
FSH and testosterone exert different regulatory effects on the seminiferous epithelium; they act through multiple and complex signaling routes to direct the development of the germ cells into mature spermatozoa. In addition to their well-known pathways of action, both hormones have recently been recognized to have new signaling routes that are linked to the Ca(2+) ion, including, among others, the regulation of cell proliferation by FSH and the regulation of cell migration by testosterone.
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Affiliation(s)
- E S Loss
- Departamento de Fisiologia, ICBS, UFRGS, Porto Alegre, RS, Brazil
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Grillo ML, Jacobus AP, Scalco R, Amaral F, Rodrigues DO, Loss ES, Wassermann GF. Testosterone rapidly stimulates insulin release from isolated pancreatic islets through a non-genomic dependent mechanism. Horm Metab Res 2005; 37:662-5. [PMID: 16308833 DOI: 10.1055/s-2005-870575] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The action of testosterone on the 45Ca2+ uptake and insulin secretion was studied in short-term experiments using isolated pancreatic islets of Langerhans. Testosterone (1 microM) stimulated 45Ca2+ uptake within 60 seconds of incubation on similar proportion than tolbutamide. Also, the hormone rapidly increased insulin release (34%; 180 seconds) on the presence of non-stimulatory concentrations of glucose (3 mM). Impermeant testosterone-BSA significantly stimulated the secretion of insulin to a lower percentage (10%). The action of the hormone is specific--neither 17beta-E2 nor progesterone stimulated insulin secretion in the presence of 3 mM glucose. The action of testosterone on insulin secretion was dose-dependent, and at rat plasma physiological concentrations (25 nM), stimulus was 17% (p < 0.05). In conclusion, in isolated pancreatic islets experiments, physiological concentration of testosterone rapidly stimulate insulin secretion and 45Ca2+ uptake through a membrane bound mechanism.
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Affiliation(s)
- M L Grillo
- Departamento de Fisiologia, ICBS, UFRGS, Porto Alegre, Brazil
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Jacobus AP, Rodrigues DO, Borba PF, Loss ES, Wassermann GF. Isoproterenol opens K+(ATP) channels via a beta2-adrenoceptor-linked mechanism in Sertoli cells from immature rats. Horm Metab Res 2005; 37:198-204. [PMID: 15952077 DOI: 10.1055/s-2005-861414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In the present study, we investigated the mechanism by which isoproterenol hyperpolarises membrane potential (MP) in Sertoli cells from seminiferous tubules of 15-day-old rat testes. Modification of MP and resistance (R0) was analysed using conventional intracellular glass microelectrodes. Isoproterenol (2 x 10(-6) M) induced an immediate and significant hyperpolarisation in the Sertoli-cell membrane. The beta2-AR antagonist, butoxamine (1 x 10(-6) M), nullified isoproterenol action. The effect of the beta1 antagonist, metoprolol (1 x 10(-6) M), was light and non-significant. Sulphonylurea glibenclamide inhibition of the K+(ATP) channels suppressed isoproterenol action, and testosterone, while depolarising Sertoli-cell MP closing the K+(ATP) channels through the PLC/PIP2 pathway, reduced beta-AR agonist-induced hyperpolarisation. Also, polycations LaCl3 and spermine reversed isoproterenol's hyperpolarisation effect, probably depolarising the membrane potential through ionic interaction neutralising the action of isoproterenol on K+(ATP) channels. Adenylate cyclase agonist forskolin (0.1 microM) rapidly hyperpolarised Sertoli-cell MP, mimicking the isoproterenol effect. These effects indicate that isoproterenol's action on K+(ATP) channel probably involves the known signalling cascade beta-AR/Gs/AC/cAMP/PKA. These results suggest that the isoproterenol-induced hyperpolarisation is mediated by the opening of K+(ATP) channels in Sertoli cells. This beta-adrenergic hyperpolarisation might play a physiological role in the modulation of MP.
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Affiliation(s)
- A P Jacobus
- Departamento de Fisiologia ICBS, UFRGS, Porto Alegre, Brazil
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Loss ES, Jacobsen M, Costa ZS, Jacobus AP, Borelli F, Wassermann GF. Testosterone modulates K(+)ATP channels in Sertoli cell membrane via the PLC-PIP2 pathway. Horm Metab Res 2004; 36:519-25. [PMID: 15326560 DOI: 10.1055/s-2004-825753] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Testosterone at physiological intratesticular concentrations induces a dose-dependent depolarisation and an increase in input resistance together with an increment of 45Ca2+ uptake in the Sertoli cells from seminiferous tubules of immature rat. Previous studies have implicated K(+)ATP channels in these testosterone actions. This study demonstrates that testosterone and sulphonylureas (glibenclamide and tolbutamide) depolarise the membrane potential, augment resistance and 45Ca2+ uptake in the Sertoli cells of seminiferous tubules from 10-15 day-old rats. These actions were nullified by the presence of the K(+)ATP channel opener diazoxide. The depolarisation was also observed with the impermeant bovine serum albumin-bound testosterone. Testosterone actions were blocked by both pertussis toxin and the phospholipase C (PLC) inhibitor U73122 implying the involvement of PLC - phosphatidylinositol 4-5 bisphosphate (PIP2) hydrolysis via G protein in testosterone actions. Polycations, including spermine and LaCl3, depolarised the membrane potential and increased the resistance. Hyperpolarisation caused by EGTA was reversed by LaCl3 and by the presence of testosterone. This last effect was nullified by the presence of U73122. All of the above results indicate that the action of testosterone on the Sertoli cell membrane is exercised on the K(+)ATP channels through PLC-PIP2 hydrolysis that closes the channel, depolarises the membrane, and stimulates 45Ca2+ uptake.
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Affiliation(s)
- E S Loss
- Departamento de Fisiologia ICBS, UFRGS, Porto Alegre, Brazil
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