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Ingelson-Filpula WA, Storey KB. MicroRNA biogenesis proteins follow tissue-dependent expression during freezing in Dryophytes versicolor. J Comp Physiol B 2022; 192:611-622. [PMID: 35748902 DOI: 10.1007/s00360-022-01444-7] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/09/2022] [Accepted: 05/31/2022] [Indexed: 10/17/2022]
Abstract
Grey tree frogs (Dryophytes versicolor) have the remarkable ability to endure full-body freezing over the winter, with up to 42% of total body water converted into extracellular ice. Survival is aided by metabolic rate depression that greatly reduces tissue energy costs over the winter. Post-transcriptional controls on gene expression which include miRNA regulation of gene transcripts can aid implementation of the reversible changes required for freeze tolerance, since miRNAs are ideal for facilitating the rapid metabolic reorganization needed for this process. The energy cost for synthesizing new miRNAs is low, and miRNAs' ability to target more than one mRNA transcript (and vice versa) allows a wide versatility in their capability for metabolic restructuring. Western immunoblotting was used to examine protein expression levels of members of the miRNA biogenesis pathway in D. versicolor liver, skeletal muscle, and kidney. Four of these proteins (Dicer, Drosha, Trbp, Xpo5) were upregulated in liver of frozen frogs, suggesting enhanced capacity for miRNA biogenesis, whereas expression of four proteins in frozen muscle (Ago1, Ago2, Dgcr8, Xpo5) and six proteins in kidney (Ago1, Ago2, Ago3, Ago4, Dgcr8, Ran-GTP) were downregulated, indicating an opposite trend. Overall, the data show that miRNA biosynthesis is altered during freezing and differentially regulated across tissues. We suggest that miRNAs are central for the freeze tolerance strategy developed by D. versicolor, and future research will expound upon specific miRNAs and their roles in mediating responses to freezing stress.
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Affiliation(s)
| | - Kenneth B Storey
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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Farias DL, Lucena MN, Garçon DP, Mantelatto FL, McNamara JC, Leone FA. A Kinetic Characterization of the Gill (Na +, K +)-ATPase from the Semi-terrestrial Mangrove Crab Cardisoma guanhumi Latreille, 1825 (Decapoda, Brachyura). J Membr Biol 2017; 250:517-534. [PMID: 28840273 DOI: 10.1007/s00232-017-9978-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 08/09/2017] [Indexed: 11/25/2022]
Abstract
We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the semi-terrestrial mangrove crab Cardisoma guanhumi. Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na+, K+)-ATPase activity, but also containing other microsomal ATPases. The (Na+, K+)-ATPase, notably immuno-localized to the apical region of the epithelial pillar cells, and throughout the pillar cell bodies, has an M r of around 110 kDa and hydrolyzes ATP with V M = 146.8 ± 6.3 nmol Pi min-1 mg protein-1 and K M = 0.05 ± 0.003 mmol L-1 obeying Michaelis-Menten kinetics. While stimulation by Na+ (V M = 139.4 ± 6.9 nmol Pi min-1 mg protein-1, K M = 4.50 ± 0.22 mmol L-1) also follows Michaelis-Menten kinetics, modulation of (Na+, K+)-ATPase activity by MgATP (V M = 136.8 ± 6.5 nmol Pi min-1 mg protein-1, K 0.5 = 0.27 ± 0.04 mmol L-1), K+ (V M = 140.2 ± 7.0 nmol Pi min-1 mg protein-1, K 0.5 = 0.17 ± 0.008 mmol L-1), and NH4+ (V M = 149.1 ± 7.4 nmol Pi min-1 mg protein-1, K 0.5 = 0.60 ± 0.03 mmol L-1) shows cooperative kinetics. Ouabain (K I = 52.0 ± 2.6 µmol L-1) and orthovanadate (K I = 1.0 ± 0.05 µmol L-1) inhibit total ATPase activity by around 75%. At low Mg2+ concentrations, ATP is an allosteric modulator of the enzyme. This is the first study to provide a kinetic characterization of the gill (Na+, K+)-ATPase in C. guanhumi, and will be useful in better comprehending the biochemical underpinnings of osmoregulatory ability in a semi-terrestrial mangrove crab.
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Affiliation(s)
- Daniel L Farias
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Prêto, SP, 14040-901, Brazil
| | - Malson N Lucena
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Prêto, SP, 14040-901, Brazil
| | - Daniela P Garçon
- DPG, Campus Universitário de Iturama, Universidade Federal do Triângulo Mineiro, Iturama, Minas Gerais, 38280-000, Brazil
| | - Fernando L Mantelatto
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Prêto, SP, 14040-901, Brazil
| | - John C McNamara
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Prêto, SP, 14040-901, Brazil
- Centro de Biologia Marinha, São Sebastião, SP, 11000-600, Brazil
| | - Francisco A Leone
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Prêto, SP, 14040-901, Brazil.
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Abstract
There are estimated to be >300,000 plant species, producing >200,000 metabolites. Many of these metabolites are restricted to specific plant lineages and are referred to as "specialized" metabolites. These serve varied functions in plants including defense against biotic and abiotic stresses, plant-plant and plant-microbe communication, and pollinator attraction. These compounds also have important applications in agriculture, medicine, skin care, and in diverse aspects of human culture. The specialized metabolic repertoire of plants can vary even within and between closely related species, in terms of the number and classes of specialized metabolites as well as their structural variants. This phenotypic variation can be exploited to discover the underlying variation in the metabolic enzymes. We describe approaches for using the diversity of specialized metabolites and variation in enzyme structure and function to identify novel enzymatic activities and understand the structural basis for these differences. The knowledge obtained from these studies will provide new modules for the synthetic biology toolbox.
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Affiliation(s)
- P Fan
- Michigan State University, East Lansing, MI, United States
| | - G D Moghe
- Michigan State University, East Lansing, MI, United States
| | - R L Last
- Michigan State University, East Lansing, MI, United States.
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