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Schwarzenberger A, Chen L, Weiss LC. The expression of circadian clock genes in Daphnia magna diapause. Sci Rep 2020; 10:19928. [PMID: 33199823 DOI: 10.1038/s41598-020-77065-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022] Open
Abstract
Diapause is a mechanism necessary for survival in arthropods. Often diapause induction and resurrection is light-dependent and therefore dependent on the photoperiod length and on the number of consecutive short-days. In many organisms, including the microcrustacean Daphnia magna, one functional entity with the capacity to measure seasonal changes in day-length is the circadian clock. There is a long-standing discussion that the circadian clock also controls photoperiod-induced diapause. We tested this hypothesis in D. magna, an organism which goes into a state of suspended animation with the shortening of the photoperiod. We measured gene expression of clock genes in diapause-destined embryos of D. magna in the initiation, resting and resurrection phases and checked it against gene expression levels of continuously developing embryos. We demonstrate that some genes of the clock are differentially expressed during diapause induction but not during its maintenance. Furthermore, the photoreceptor gene cry2 and the clock-associated gene brp are highly expressed during induction and early diapause, probably in order to produce excess mRNA to prepare for immediate resurrection. After resurrection, both types of embryos show a similar pattern of gene expression during development. Our study contributes significantly to the understanding of the molecular basis of diapause induction, maintenance and termination.
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Stan RC, Bhatt DK, Camargo MM. Cellular Adaptation Relies on Regulatory Proteins Having Episodic Memory. Bioessays 2019; 42:e1900115. [DOI: 10.1002/bies.201900115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/06/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Razvan C. Stan
- Cantacuzino National Military‐Medical Institute for Research‐Development Bucharest 050096 Romania
- Department of ImmunologyUniversity of São Paulo São Paulo 05508‐900 Brazil
| | - Darshak K. Bhatt
- Faculty of Medical SciencesGroningen University Groningen 9700 AB The Netherlands
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Affiliation(s)
- Razvan C. Stan
- Immunology DepartmentUniversity of São Paulo Brazil
- Cantacuzino Military-Medical Research-Development National Institute, Bucharest Romania
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Schwartz L, Lafitte O, da Veiga Moreira J. Toward a Reasoned Classification of Diseases Using Physico-Chemical Based Phenotypes. Front Physiol 2018. [PMID: 29541031 PMCID: PMC5835834 DOI: 10.3389/fphys.2018.00094] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Diseases and health conditions have been classified according to anatomical site, etiological, and clinical criteria. Physico-chemical mechanisms underlying the biology of diseases, such as the flow of energy through cells and tissues, have been often overlooked in classification systems. Objective: We propose a conceptual framework toward the development of an energy-oriented classification of diseases, based on the principles of physical chemistry. Methods: A review of literature on the physical chemistry of biological interactions in a number of diseases is traced from the point of view of the fluid and solid mechanics, electricity, and chemistry. Results: We found consistent evidence in literature of decreased and/or increased physical and chemical forces intertwined with biological processes of numerous diseases, which allowed the identification of mechanical, electric and chemical phenotypes of diseases. Discussion: Biological mechanisms of diseases need to be evaluated and integrated into more comprehensive theories that should account with principles of physics and chemistry. A hypothetical model is proposed relating the natural history of diseases to mechanical stress, electric field, and chemical equilibria (ATP) changes. The present perspective toward an innovative disease classification may improve drug-repurposing strategies in the future.
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Affiliation(s)
| | - Olivier Lafitte
- LAGA, UMR 7539, Paris 13 University, Sorbonne Paris Cité, Villetaneuse, France
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Schwartz L, da Veiga Moreira J, Jolicoeur M. Physical forces modulate cell differentiation and proliferation processes. J Cell Mol Med 2018; 22:738-745. [PMID: 29193856 PMCID: PMC5783863 DOI: 10.1111/jcmm.13417] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/12/2017] [Indexed: 01/06/2023] Open
Abstract
Currently, the predominant hypothesis explains cellular differentiation and behaviour as an essentially genetically driven intracellular process, suggesting a gene-centrism paradigm. However, although many living species genetic has now been described, there is still a large gap between the genetic information interpretation and cell behaviour prediction. Indeed, the physical mechanisms underlying the cell differentiation and proliferation, which are now known or suspected to guide such as the flow of energy through cells and tissues, have been often overlooked. We thus here propose a complementary conceptual framework towards the development of an energy-oriented classification of cell properties, that is, a mitochondria-centrism hypothesis based on physical forces-driven principles. A literature review on the physical-biological interactions in a number of various biological processes is analysed from the point of view of the fluid and solid mechanics, electricity and thermodynamics. There is consistent evidence that physical forces control cell proliferation and differentiation. We propose that physical forces interfere with the cell metabolism mostly at the level of the mitochondria, which in turn control gene expression. The present perspective points towards a paradigm shift complement in biology.
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Affiliation(s)
| | | | - Mario Jolicoeur
- Research Laboratory in Applied Metabolic EngineeringDepartment of Chemical EngineeringÉcole Polytechnique de MontréalMontréalQCCanada
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MacRae TH. Stress tolerance during diapause and quiescence of the brine shrimp, Artemia. Cell Stress Chaperones 2016; 21:9-18. [PMID: 26334984 PMCID: PMC4679736 DOI: 10.1007/s12192-015-0635-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [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: 06/22/2015] [Revised: 08/12/2015] [Accepted: 08/24/2015] [Indexed: 02/06/2023] Open
Abstract
Oviparously developing embryos of the brine shrimp, Artemia, arrest at gastrulation and are released from females as cysts before entering diapause, a state of dormancy and stress tolerance. Diapause is terminated by an external signal, and growth resumes if conditions are permissible. However, if circumstances are unfavorable, cysts enter quiescence, a dormant stage that continues as long as adverse conditions persist. Artemia embryos in diapause and quiescence are remarkably resistant to environmental and physiological stressors, withstanding desiccation, cold, heat, oxidation, ultraviolet radiation, and years of anoxia at ambient temperature when fully hydrated. Cysts have adapted to stress in several ways; they are surrounded by a rigid cell wall impermeable to most chemical compounds and which functions as a shield against ultraviolet radiation. Artemia cysts contain large amounts of trehalose, a non-reducing sugar thought to preserve membranes and proteins during desiccation by replacing water molecules and/or contributing to vitrification. Late embryogenesis abundant proteins similar to those in seeds and other anhydrobiotic organisms are found in cysts, and they safeguard cell organelles and proteins during desiccation. Artemia cysts contain abundant amounts of p26, a small heat shock protein, and artemin, a ferritin homologue, both ATP-independent molecular chaperones important in stress tolerance. The evidence provided in this review supports the conclusion that it is the interplay of these protective elements that make Artemia one of the most stress tolerant of all metazoan organisms.
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Affiliation(s)
- Thomas H MacRae
- Department of Biology, Dalhousie University, Halifax, N.S., B3H 4R2, Canada.
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da Veiga Moreira J, Peres S, Steyaert JM, Bigan E, Paulevé L, Nogueira ML, Schwartz L. Cell cycle progression is regulated by intertwined redox oscillators. Theor Biol Med Model 2015; 12:10. [PMID: 26022743 PMCID: PMC4459109 DOI: 10.1186/s12976-015-0005-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/15/2015] [Indexed: 01/04/2023] Open
Abstract
The different phases of the eukaryotic cell cycle are exceptionally well-preserved phenomena. DNA decompaction, RNA and protein synthesis (in late G1 phase) followed by DNA replication (in S phase) and lipid synthesis (in G2 phase) occur after resting cells (in G0) are committed to proliferate. The G1 phase of the cell cycle is characterized by an increase in the glycolytic metabolism, sustained by high NAD+/NADH ratio. A transient cytosolic acidification occurs, probably due to lactic acid synthesis or ATP hydrolysis, followed by cytosolic alkalinization. A hyperpolarized transmembrane potential is also observed, as result of sodium/potassium pump (NaK-ATPase) activity. During progression of the cell cycle, the Pentose Phosphate Pathway (PPP) is activated by increased NADP+/NADPH ratio, converting glucose 6-phosphate to nucleotide precursors. Then, nucleic acid synthesis and DNA replication occur in S phase. Along with S phase, unpublished results show a cytosolic acidification, probably the result of glutaminolysis occurring during this phase. In G2 phase there is a decrease in NADPH concentration (used for membrane lipid synthesis) and a cytoplasmic alkalinization occurs. Mitochondria hyperfusion matches the cytosolic acidification at late G1/S transition and then triggers ATP synthesis by oxidative phosphorylation. We hypothesize here that the cytosolic pH may coordinate mitochondrial activity and thus the different redox cycles, which in turn control the cell metabolism.
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Affiliation(s)
| | - Sabine Peres
- LRI, Paris-Sud University, CNRS UMR8623 and INRIA Saclay, Paris, France.
| | | | - Erwan Bigan
- Ecole Polytechnique, LIX-UMR 7161, Palaiseau, France.
| | - Loïc Paulevé
- Ecole Polytechnique, LIX-UMR 7161, Palaiseau, France. .,LRI, Paris-Sud University, CNRS UMR8623 and INRIA Saclay, Paris, France.
| | - Marcel Levy Nogueira
- Ecole Polytechnique, LIX-UMR 7161, Palaiseau, France. .,Paris Institute of Translationnal Neurosciences (IHU-A-ICM), Pitié Salpêtrière Hospital, Paris, France.
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Yang F, Chen S, Dai ZM, Chen DF, Duan RB, Wang HL, Jia SN, Yang WJ. Regulation of trehalase expression inhibits apoptosis in diapause cysts of Artemia. Biochem J 2013; 456:185-94. [PMID: 24063546 DOI: 10.1042/BJ20131020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Trehalase, which specifically hydrolyses trehalose into glucose, plays an important role in the metabolism of trehalose. Large amounts of trehalose are stored in the diapause encysted embryos (cysts) of Artemia, which are not only vital to their extraordinary stress resistance, but also provide a source of energy for development after diapause is terminated. In the present study, a mechanism for the transcriptional regulation of trehalase was described in Artemia parthenogenetica. A trehalase-associated protein (ArTAP) was identified in Artemia-producing diapause cysts. ArTAP was found to be expressed only in diapause-destined embryos. Further analyses revealed that ArTAP can bind to a specific intronic segment of a trehalase gene. Knockdown of ArTAP by RNAi resulted in the release of cysts with coarse shells in which two chitin-binding proteins were missing. Western blotting showed that the level of trehalase was increased and apoptosis was induced in these ArTAP-knockdown cysts compared with controls. Taken together, these results show that ArTAP is a key regulator of trehalase expression which, in turn, plays an important role in trehalose metabolism during the formation of diapause cysts.
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Wu Z, Xing J. Functional roles of slow enzyme conformational changes in network dynamics. Biophys J 2013; 103:1052-9. [PMID: 23009855 DOI: 10.1016/j.bpj.2012.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 07/31/2012] [Accepted: 08/02/2012] [Indexed: 11/29/2022] Open
Abstract
Extensive studies from different fields reveal that many macromolecules, especially enzymes, show slow transitions among different conformations. This phenomenon is named such things as dynamic disorder, heterogeneity, hysteretic or mnemonic enzymes across these different fields, and has been directly demonstrated by single molecule enzymology and NMR studies recently. We analyzed enzyme slow conformational changes in the context of regulatory networks. A single enzymatic reaction with slow conformational changes can filter upstream network noises, and can either resonantly respond to the system stimulus at certain frequencies or respond adaptively for sustained input signals of the network fluctuations. It thus can serve as a basic functional motif with properties that are normally for larger intermolecular networks in the field of systems biology. We further analyzed examples including enzymes functioning against pH fluctuations, metabolic state change of Artemia embryos, and kinetic insulation of fluctuations in metabolic networks. The study also suggests that hysteretic enzymes may be building blocks of synthetic networks with various properties such as narrow-banded filtering. The work fills the missing gap between studies on enzyme biophysics and network level dynamics, and reveals that the coupling between the two is functionally important; it also suggests that the conformational dynamics of some enzymes may be evolutionally selected.
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Affiliation(s)
- Zhanghan Wu
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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Patil YN, Marden B, Brand MD, Hand SC. Metabolic downregulation and inhibition of carbohydrate catabolism during diapause in embryos of Artemia franciscana. Physiol Biochem Zool 2012; 86:106-18. [PMID: 23303325 DOI: 10.1086/667808] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Diapause embryos were collected from ovigerous females of Artemia franciscana at the Great Salt Lake, Utah, and were synchronized to within 4 h of release. Respiration rate for these freshly released embryos across a subsequent 26-d time course showed a rapid decrease during the first several days followed thereafter by a much slower decline. The overall metabolic depression was estimated to be greater than 99%. However, proton conductance of mitochondria isolated from diapause and postdiapause embryos was identical. Because proton leak is apparently not downregulated during diapause, mitochondrial membrane potential is likely compromised because of the very low metabolic rate observed for diapause embryos. Given that trehalose is the primary fuel used by these embryos, we measured metabolic intermediates along the catabolic pathway from trehalose to acetyl-CoA for both diapause and postdiapause (active) embryos in order to identify sites of metabolic inhibition. Comparison of product-to-substrate ratios for sequential enzymatic steps revealed inhibition during diapause at trehalase, hexokinase, pyruvate kinase, and pyruvate dehydrogenase. Measurements of ATP, ADP, and AMP allowed calculations of substantial decreases in ATP:ADP ratio and in adenylate energy charge during diapause. The phosphorylation of site 1 for pyruvate dehydrogenase (PDH) subunit E1α was higher in diapause embryos than in postdiapause embryos, which is consistent with PDH inhibition during diapause. Taken together, our findings indicate that restricted substrate availability to mitochondria for oxidative phosphorylation contributes to downregulating metabolic rate during diapause.
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Affiliation(s)
- Yuvraj N Patil
- Division of Cellular, Developmental, and Integrative Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Abstract
Continuous measurement of heat dissipation from brine shrimp embryos during reversible transitions from aerobic development to anaerobic dormancy demonstrates a primary role for intracellular pH(pH(i))in this metabolic switching. Artificially elevating the depressed pH(i) during anoxia by adding ammonia markedly reactivates metabolism, as judged by increases in heat dissipation, trehalose catabolism, and the ratio of adenosine triphosphate to adenosine diphosphate. Energy flow during anaerobic dormancy is suppressed to 2.4 percent of aerobic values, which is the lowest percentage thus far reported for euryoxic animals. Use of diguanosine tetraphosphate stores cannot account for this observed heat dissipation. Thus, mobilizing trace amounts of trehalose may explain the energy metabolism during quiescence.
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Meza-Herrera CA, Ross T, Hawkins D, Hallford D. Interactions between metabolic status, pre-breeding protein supplementation, uterine pH, and embrionic mortality in ewes: preliminary observations. Trop Anim Health Prod 2007; 38:407-13. [PMID: 17165612 DOI: 10.1007/s11250-006-4331-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The effect of prebreeding short-term protein supplementation level (PL) and body condition (BC) on fertility rate (FERT,%), uterine pH and embryonic mortality (EMORT,%) in sheep, was evaluated. Multiparous Rambouillet ewes at low BC (LC; n = 6, 62.7+/-1.7 kg) or high BC (HC; n = 6, 71.9 +/-1.7 kg), received, within BC, one of two levels of ruminally undegradable protein: low (LP, 14 g/ewe per day) and high (HP, 30 g/ewe per day). Once the animals were euthanized, corpus luteum number (CLN), as an indicator of ovulation rate, was registered and uterine horns were irrigated to recover embryonic tissue plus associated membranes as well as to measure uterine pH (UpH). While EMORT- 1 considered a nonadjusted relationship between the number of embryos and CLN, EMORT-2 considered an analysis of covariance using CLN as the covariate. The HP-supplemented ewes had the lowest FERT (p = 0.06; 100% vs 50%) and the highest EMORT (EMORT-1, 16.6% vs 53.8%, p = 0.08; EMORT-2, 52.0% vs 14.5%, p = 0.07) when compared to the LP-supplemented ewes. Neither BC nor PL affected CLN, CL weight or P4 release (p > 0.10). While the lowest UpH (p = 0.04) was observed in the HP-supplemented ewes, this group also showed the lowest fertility and the highest embryonic mortality.
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Affiliation(s)
- C A Meza-Herrera
- Unidad Regional Universitaria de Zonas Aridas, Universidad Autónoma Chapingo, Mexico.
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Abstract
To identify factors responsible for the down-regulation of mitochondrial biosynthetic processes during anoxia in encysted Artemia franciscana embryos, the effects of oxygen limitation and pH on protein synthesis were investigated in isolated mitochondria. At the optimal pH of 7.5, exposure of mitochondria to anoxia decreases the protein synthesis rate by 79%. Rates were suppressed by a further 10% at pH 6.8, the intracellular pH (pHi) measured under anoxia in vivo. Matrix pH, measured under identical conditions, was 8.43 +/- 0.01 at an extra-mitochondrial pH of 7.9 (mean +/- S.E.M., n = 3), 8.05 +/- 0.01 at pH 7.5, and 7.10 +/- 0.01 at pH 6.8. The matrix pH did not vary (P > or = 0.20) as a function of oxygen availability during the 1 h assays. Intramitochondrial purine nucleotides varied little as a function of pH. In contrast, after 1 h of protein synthesis under anoxia, ATP levels decreased by up to 40%, whereas AMP, ADP and GDP concentrations increased, and GTP and GMP concentrations remained relatively constant. The addition of 1 mM ATP at the onset of anoxia maintained the ATP/ADP ratio at the aerobic value, but did not stabilized the GTP/GDP ratio or rescue rates of protein synthesis. Thus, at present, we cannot eliminate the possibility that the decrease in the GTP/GDP ratio during anoxia may contribute to the suppression of protein synthesis. The effect of anoxia was reversible; the rate of protein synthesis upon reoxygenation after a 30 min bout of anoxia was comparable (P = 0.14) with the pre-anoxic rate (193 +/- 17 and 174 +/- 6 pmol of leucine per mg of protein respectively, mean +/- S.E.M., n = 3). The array of mitochondrial translation products did not differ qualitatively as a function of either oxygen availability or pH. Finally, similar pH profiles for protein synthesis were obtained with either [3H]leucine or [3H]histidine (known to use different transporters). Consequently, it is improbable that the pH-sensitivity of protein synthesis can be explained by a specific protein effect on the import of the radiolabelled amino acid used. In summary, both oxygen limitation and acidic pH suppress rates of mitochondrial protein synthesis and are likely to contribute to the arrest of mitochondrial anabolic processes during anoxia-induced quiescence in A. franciscana embryos.
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Affiliation(s)
- K E Kwast
- Department of Environmental, Population, and Organismic Biology, University of Colorado, Boulder 80309-0334, USA
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Kwast KE, Shapiro JI, Rees BB, Hand SC. Oxidative phosphorylation and the realkalinization of intracellular pH during recovery from anoxia in Artemia franciscana embryos. Biochimica et Biophysica Acta (BBA) - Bioenergetics 1995. [DOI: 10.1016/0005-2728(95)00090-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Lazou A, Frosinis A. Kinetic and regulatory properties of pyruvate kinase from Artemia embryos during incubation under aerobic and anoxic conditions. The effect of pH on the kinetic constants. ACTA ACUST UNITED AC 1994; 109:325-32. [DOI: 10.1016/0305-0491(94)90016-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Lazou A, Polydoros I, Beis I. Effect of anaerobiosis and anhydrobiosis on the extent of glycolytic enzyme binding in Artermia embryos. J Comp Physiol B 1994; 164:306-11. [DOI: 10.1007/bf00346447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Michaelidis B, Pardalidis T. Regulation of pyruvate kinase (PK) from the ventricle of the land snail Helix lucorum L. during early and prolonged estivation and hibernation. ACTA ACUST UNITED AC 1994; 107:585-91. [DOI: 10.1016/0305-0491(94)90189-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Van Der Linden A, Gadeyne J, Van Onckelen H, Van Laere A, Decleir W. Involvement of cyclic nucleotides in light-induced resumption of development ofArtemia embryos. ACTA ACUST UNITED AC 1991. [DOI: 10.1002/jez.1402580306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Microcalorimetric measurements of brine shrimp embryos during 6 days of anoxia indicated that heat dissipation was rapidly suppressed to 2.7% of control (aerobic) values over the first 9 h. Energy flow continued to decline slowly to 31 microW.g dry mass-1 (0.4% of control) during the subsequent 5.5 days. Within 2 h after returning anoxic embryos to aerobic conditions, heat dissipation rose to 77% of control rates. The calorimetric/respirometric (CR) ratio across this 2-h recovery period increased steadily from -226 to -346 kJ.mol O2-1). Prior to the anoxic exposures, hydrated embryos were incubated aerobically for 10 h to insure full initiation of carbohydrate metabolism (CR ratio = -484 kJ.mol O2-1). During the 6-day asymptotic approach to a nearly ametabolic state, trehalose and glycogen levels declined 18% and 13%, respectively. The majority of this utilization occurred within the first three days. Thermochemical calculations showed that carbohydrate catabolism accounted for 84% of the total heat dissipation measured over the 6-day anoxic bout; only 3% of the heat could be explained by the catabolism of diguanosine tetraphosphate (Gp4G). Analyses of embryo extracts by high performance liquid chromatography indicated that multiple acid end products were accumulated. Lactate and propionate reached 4.5 mM and 1.0 mM, respectively, but these compounds did not account quantitatively for the amount of carbohydrate utilized. However, the largest chromatographic peak that accumulated under anoxia has not been successfully identified. Fumarate and pyruvate levels decreased as anoxia proceeded. Thus, a perceptible energy flow in Artemia franciscana embryos still remained after 6 days of anoxia.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S C Hand
- Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80309-0334
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Hofmann GE, Hand SC. Subcellular differentiation arrested inArtemia embryos under anoxia: Evidence supporting a regulatory role for intracellular pH. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/jez.1402530308] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Erdmann H, Griesbach RJ, Lawson RH, Mattoo AK. 1-Aminocyclopropane-1-carboxylic-acid-dependent ethylene production during re-formation of vacuoles in evacuolated protoplasts of Petunia hybrida. Planta 1989; 179:196-202. [PMID: 24201518 DOI: 10.1007/bf00393689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/1989] [Accepted: 05/12/1989] [Indexed: 06/02/2023]
Abstract
Ethylene formation from 1-aminocycloprane-1-carboxylic acid (ACC) was studied in whole protoplasts, evaluolated protoplasts and isolated vacuoles from mesophyll cells of Petunia hybrida L. cv. Pink Magic. The re-formation of the large, central vacuole in evacuolated protoplasts and morphological characteristics of both types of protoplasts were examined by electron microscopy. Both the normal, whole protoplasts and vacuoles isolated from them produced ethylene from ACC at similar rates. Freshly-prepared evacuolated protoplasts had lost the capacity to produce ethylene. Re-formation of the central vacuole in these evacuolated protoplasts occurred between 14 to 17 h of incubation in the recovery medium and was followed by the development of ethyleneforming activity. Both these processes were inhibited by cycloheximide, indicating a requirement for new protein synthesis. Light stimulated the conversion of ACC to ethylene in both the regenerating, whole protoplasts and the evacuolated protoplasts that had re-formed the central vacuole.
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Affiliation(s)
- H Erdmann
- Florist and Nursery Crops, U. S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center-West, 20705, Beltsville, MD, USA
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Hazel JR. Cold Adaptation in Ectotherms: Regulation of Membrane Function and Cellular Metabolism. Advances in Comparative and Environmental Physiology 1989. [DOI: 10.1007/978-3-642-74078-7_1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Van Der Linden A, Blust R, Van Laere AJ, Decleir W. Light-induced release ofArtemia dried embryos from diapause: Analysis of metabolic status. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/jez.1402470204] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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MEER JITSEMVANDER. THE ROLE OF METABOLISM AND CALCIUM IN THE CONTROL OF MITOSIS AND OOPLASMIC MOVEMENTS IN INSECT EGGS: A WORKING HYPOTHESIS. Biol Rev Camb Philos Soc 1988. [DOI: 10.1111/j.1469-185x.1988.tb00628.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Phosphofructokinase (PFK) purified from rabbit skeletal muscle is fully inactivated after air-drying and rehydration. The addition of trehalose, maltose, or sucrose to the enzyme solution prior to rapid drying results in a recovery of almost 70% of the original activity, whereas about 30% is recovered during slow drying. Similar stabilization is seen with up to 200 mM lactose, but at higher concentrations the sugar comes out of solution during drying, and there is a dramatic drop in the activity recovered. Glucose at concentrations up to 500 mM is ineffective at protecting air-dried PFK. Addition of ionic zinc to enzyme-sugar mixtures prior to drying greatly enhances the stabilization imparted by the above sugars, but zinc alone affords no protection. Several other organic solutes (proline, glycine, trimethylamine N-oxide, glycerol, and myo-inositol) that afford cryoprotection to PFK, an effect enhanced by the addition of zinc, do not stabilize the enzyme during air-drying, even if zinc is present. The addition of ionic copper, cobalt, or nickel to trehalose-PFK solution prior to rapid drying results in a large increase in the activity recovered, and the presence of cadmium or manganese leads to a minor increase. Magnesium and calcium are ineffective in this respect. During slow drying, the presence of cadmium or calcium leads to increased preservation, magnesium and manganese have no influence on stabilization, and copper and nickel inactive the enzyme.
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Affiliation(s)
- J F Carpenter
- Department of Zoology, University of California, Davis 95616
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Carpenter JF, Hand SC. Arrestment of carbohydrate metabolism during anaerobic dormancy and aerobic acidosis inArtemia embryos: determination of pH-sensitive control points. J Comp Physiol B 1986; 156:451-9. [DOI: 10.1007/bf00691030] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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