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Ubierna N, Holloway-Phillips MM, Wingate L, Ogée J, Busch FA, Farquhar GD. Using Carbon Stable Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2024; 2790:163-211. [PMID: 38649572 DOI: 10.1007/978-1-0716-3790-6_10] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Meisha-Marika Holloway-Phillips
- Research Unit of Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmendsorf, Switzerland
| | - Lisa Wingate
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Jérôme Ogée
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Tofanello VR, Andrade LM, Flores-Borges DNA, Kiyota E, Mayer JLS, Creste S, Machado EC, Yin X, Struik PC, Ribeiro RV. Role of bundle sheath conductance in sustaining photosynthesis competence in sugarcane plants under nitrogen deficiency. Photosynth Res 2021; 149:275-287. [PMID: 34091828 DOI: 10.1007/s11120-021-00848-w] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
The role of bundle sheath conductance (gbs) in sustaining sugarcane photosynthesis under nitrogen deficiency was investigated. Sugarcane was grown under different levels of nitrogen supply and gbs was estimated using simultaneous measurements of leaf gas exchange and chlorophyll fluorescence at 21% or 2% [O2] and varying air [CO2] and light intensity. Maximum rates of PEPC carboxylation, Rubisco carboxylation, and ATP production increased with an increase in leaf nitrogen concentration (LNC) from 1 to 3 g m-2. Low nitrogen supply reduced Rubisco and PEPC abundancies, the quantum efficiency of CO2 assimilation and gbs. Because of reduced gbs, low photosynthetic rates were not associated with increased leakiness under nitrogen deficiency. In fact, low nitrogen supply increased bundle sheath cell wall thickness, probably accounting for low gbs and increased estimates of [CO2] at Rubisco sites. Effects of nitrogen on expression of ShPIP2;1 and ShPIP1;2 aquaporins did not explain changes in gbs. Our data revealed that reduced Rubisco carboxylation was the main factor causing low sugarcane photosynthesis at low nitrogen supply, in contrast to the previous report on the importance of an impaired CO2 concentration mechanism under N deficiency. Our findings suggest higher investment of nitrogen into Rubisco protein would favour photosynthesis and plant performance under low nitrogen availability.
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Affiliation(s)
- Vanessa R Tofanello
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Larissa M Andrade
- Centro de Cana, Instituto Agronômico (IAC), Ribeirão Preto, SP, Brazil
| | - Denisele N A Flores-Borges
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Eduardo Kiyota
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Juliana L S Mayer
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Silvana Creste
- Centro de Cana, Instituto Agronômico (IAC), Ribeirão Preto, SP, Brazil
| | - Eduardo C Machado
- Laboratory of Plant Physiology "Coaracy M. Franco", Center for Research and Development in Ecophysiology and Biophysics, IAC, Campinas, SP, Brazil
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Dept. Plant Sciences, Wageningen University & Research, Wageningen, The Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Dept. Plant Sciences, Wageningen University & Research, Wageningen, The Netherlands
| | - Rafael V Ribeiro
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Kastenhofer J, Spadiut O. Culture medium density as a simple monitoring tool for cell integrity of Escherichia coli. J Biotechnol 2020; 324S:100017. [PMID: 34154736 DOI: 10.1016/j.btecx.2020.100017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 11/20/2022]
Abstract
During the expression of recombinant proteins in the periplasm of Escherichia coli, the integrity of the outer membrane can change, so that product leaks to the medium. Additional stress can induce lysis, the complete disintegration of both inner and outer membrane, leading to release of both product and host cell proteins. Whether leakiness is unwanted or intentional, appropriate monitoring of leakiness and its distinction from lysis is necessary to ensure product quality and process performance. Here, we investigated a novel monitoring tool for leakiness and lysis based on the measurement of the culture supernatant density. The method benefits from short analysis time and low analytical error, simple result output, relatively low cost, low risk of operator errors and the option of easy on-line implementation. Although limitations exist regarding selectivity, we could show that the method is capable of detecting changes in cell integrity. This tool is therefore an interesting addition to the monitoring toolbox for industrial E. coli bioprocesses.
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Vo M, Mehrabian S, Villalpando F, Etienne S, Pelletier D, Cameron CB. The fluid dynamics of Balanus glandula barnacles: Adaptations to sheltered and exposed habitats. J Biomech 2018; 71:225-235. [PMID: 29478697 DOI: 10.1016/j.jbiomech.2018.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [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: 09/18/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
Abstract
Suspension feeders use a wide range of appendages to capture particles from the surrounding fluid. Their functioning, either as a paddle or a sieve, depends on the leakiness, or amount of fluid that passes through the gaps between the appendages. Balanus glandula is the most common species of barnacle distributed along the Pacific coast of North America. It shows a strong phenotypic response to water flow velocity. Individuals from exposed, high flow sites have short and robust cirral filters, whereas those from sheltered, low velocity sites have long, spindly appendages. Computational fluid dynamics (CFD) simulations of these two ecophenotypes were done using a finite volume method. Leakiness was determined by simulating flow velocity fields at increasing Reynolds numbers, results that have been unattainable at higher velocities by observation. CFD also allowed us to characterize flow in hard to see regions of the feeding legs (rami). Laser-illumination experiments were performed at low to medium flow velocities in a flume tank and corroborated results from CFD. Barnacle filters from a sheltered site become completely leaky at Re=2.24(0.16m/s), well above the maximum habitat velocity, suggesting that this ecophenotype is not mechanically optimized for feeding. Barnacles from exposed environments become fully leaky within the range of habitat velocities Re=3.50(0.18m/s). Our CFD results revealed that the drag force on exposed barnacles feeding appendages are the same as the sheltered barnacles feeding appendages despite their shape difference and spacing ratio.
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Affiliation(s)
- Maureen Vo
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada
| | - Sasan Mehrabian
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada
| | - Fernando Villalpando
- Ecole Polytechnique de Montreal, C.P. 6079, succ. Centre-ville, Montreal, Quebec H3C 3A7, Canada
| | - Stephane Etienne
- Ecole Polytechnique de Montreal, C.P. 6079, succ. Centre-ville, Montreal, Quebec H3C 3A7, Canada
| | - Dominique Pelletier
- Ecole Polytechnique de Montreal, C.P. 6079, succ. Centre-ville, Montreal, Quebec H3C 3A7, Canada
| | - Christopher B Cameron
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada.
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Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C-isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, tunable diode laser spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets, at low cost and with unprecedented temporal resolution. With more data and accompanying knowledge, it has become apparent that there is a need for increased complexity in models and calculations. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
| | | | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Abstract
Epithelial barrier function and innate immunity are fundamental to the pathogenesis of inflammatory and infectious disease. Along with plasma membranes, epithelial cells are the primary cellular determinant of epithelial barrier function. The mechanism by which polarized epithelia form a permeability barrier is of fundamental importance to the prevention of many infectious and inflammatory diseases. Moreover, epithelial cells express Toll-like receptors (TLRs) which upon recognition of conserved microbial factors such as lipopolysaccharide (LPS) induce epithelial responses including epithelial cell proliferation, secretion of secretory IgA into the lumen and production mucins and antimicrobial peptides, thereby promoting intestinal barrier function. Understanding gut barrier integrity and regulation of permeability is crucial to increase our understanding of the pathogenesis of intestinal disease. A variety of tests have been developed to assess this barrier, including assessing intestinal epithelial cell proliferation or death, intestinal tight junction status and the consequence of intestinal barrier integrity loss such as increased intestinal permeability and susceptibility to bacterial infection. Using a mouse model, this chapter describes some of the methods to assess the functional integrity of this epithelial barrier and the part played by a TLR signalling pathway.
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Affiliation(s)
- Daniel G W Johnston
- Trinity Biomedical Sciences Institute, School of Biochemistry and Immunology, Trinity College Dublin, Pearse Street, Dublin 2, Ireland
| | - Sinéad C Corr
- Trinity Biomedical Sciences Institute, School of Biochemistry and Immunology, Trinity College Dublin, Pearse Street, Dublin 2, Ireland.
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Börgers C, Li J, Kopell N. Approximate, not Perfect Synchrony Maximizes the Downstream Effectiveness of Excitatory Neuronal Ensembles. J Math Neurosci 2014; 4:10. [PMID: 27334376 PMCID: PMC4916341 DOI: 10.1186/2190-8567-4-10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/28/2014] [Indexed: 06/06/2023]
Abstract
The most basic functional role commonly ascribed to synchrony in the brain is that of amplifying excitatory neuronal signals. The reasoning is straightforward: When positive charge is injected into a leaky target neuron over a time window of positive duration, some of it will have time to leak back out before an action potential is triggered in the target, and it will in that sense be wasted. If the goal is to elicit a firing response in the target using as little charge as possible, it seems best to deliver the charge all at once, i.e., in perfect synchrony. In this article, we show that this reasoning is correct only if one assumes that the input ceases when the target crosses the firing threshold, but before it actually fires. If the input ceases later-for instance, in response to a feedback signal triggered by the firing of the target-the "most economical" way of delivering input (the way that requires the least total amount of input) is no longer precisely synchronous, but merely approximately so. If the target is a heterogeneous network, as it always is in the brain, then ceasing the input "when the target crosses the firing threshold" is not an option, because there is no single moment when the firing threshold is crossed. In this sense, precise synchrony is never optimal in the brain.
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Affiliation(s)
- Christoph Börgers
- />Department of Mathematics, Tufts University, Medford, MA 02155 USA
| | - Jie Li
- />Department of Mathematics, Tufts University, Medford, MA 02155 USA
| | - Nancy Kopell
- />Department of Mathematics and Statistics, Boston University, Boston, MA 02215 USA
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Abstract
Though much progress has been made in the development of anti-tumor chemotherapeutic agents, refractoriness is still a major clinical difficulty because little is known about the non-autonomous mechanisms involved. Abnormal capillary structures in tumors, for example, are well documented, but a thorough characterization of microcirculation, including functional consequences with particular regard to drug delivery and intratumor accumulation, is still required for many kinds of tumor. In this review, we highlight how use of synthesized nanoparticles, themselves a product of emerging nanotechnology, are beginning to open up new perspectives in understanding the functional and therapeutic consequences of capillary structure within tumors. Furthermore, nanoparticles promise exciting new clinical applications. I also stress the urgent necessity of developing clinically relevant tumor models, both in vivo and in vitro.
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Fujii E, Kato A, Chen YJ, Matsubara K, Ohnishi Y, Suzuki M. Histopathological characteristics of human non-tumor thyroid tissues in a long-term model of adenomatous goiter xenografts in the NOD/Shi-scid, IL-2Rγ(null) mouse. ACTA ACUST UNITED AC 2014; 66:203-9. [PMID: 24589354 DOI: 10.1016/j.etp.2014.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 09/19/2013] [Revised: 12/20/2013] [Accepted: 01/28/2014] [Indexed: 11/17/2022]
Abstract
There is a growing need for modeling the human thyroid to link data obtained from animals to humans because of its sensitivity to radiation exposure and endocrine disruption chemicals. In a scid mouse model produced by transplanting human thyroid tissues, leakiness and thymic lymphoma that occurs spontaneously in the scid mouse can complicate the interpretation of experimental results. Considering that the NOD.Cg-Prkdc(scid)Il2rg(tm1Sug)/Jic mouse (NOD/Shi-scid, IL-2Rγ(null) or NOG mouse) may be a better host because this strain has low incidence of leakiness and thymic lymphoma, we have evaluated the potential of a model that allows long-term observation of non-tumor human thyroid tissues in this mouse. We transplanted tissues of human adenomatous goiter into NOG mice and examined the tissues histopathologically. The morphology of human adenomatous goiter tissues was maintained from 24 to 44 weeks after transplantation in NOG mice with no noted differences between donor-matched tissues or the weeks after transplantation. The tissues expressed thyroglobulin protein and mRNA as well as thyroperoxidase. Endothelial cells originating from human were found in the transplanted tissues and were thought to be a characteristic of this model. The intactness of the tissues before transplantation was found to affect the rate of tissue engraftment. From the present results we have concluded that transplanted thyroid tissues in NOG mice maintain the histopathological characteristics of their origin for long terms. Therefore this model was thought feasible for toxicity evaluation.
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Affiliation(s)
- Etsuko Fujii
- Research Division, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan.
| | - Atsuhiko Kato
- Research Division, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
| | - Yu Jau Chen
- PharmaLogicals Research, Pte. Ltd., 11 Biopolis Way, #05-08/09 Helios, Singapore 138667, Singapore
| | - Koichi Matsubara
- PharmaLogicals Research, Pte. Ltd., 11 Biopolis Way, #05-08/09 Helios, Singapore 138667, Singapore
| | - Yasuyuki Ohnishi
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki 210-0821, Japan
| | - Masami Suzuki
- Research Division, Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan
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