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Mor Khalifa G, Levy S, Mass T. The calcifying interface in a stony coral primary polyp: An interplay between seawater and an extracellular calcifying space. J Struct Biol 2021; 213:107803. [PMID: 34695544 DOI: 10.1016/j.jsb.2021.107803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 10/07/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022]
Abstract
Stony coral exoskeletons build the foundation for the most biologically diverse marine ecosystems on Earth, coral reefs, which face major threats due to many anthropogenic-related stressors. Therefore, understanding coral biomineralization mechanisms is crucial for coral reef management in the coming decades and for using coral skeletons in geochemical studies. This study combines in-vivo imaging with cryo-electron microscopy and cryo-elemental mapping to gain novel insights into the biological microenvironment and the ion pathways that facilitate biomineralization in primary polyps of the stony coral Stylophora pistillata. We document increased tissue permeability in the primary polyp and a highly dispersed cell packing in the tissue directly responsible for producing the coral skeleton. This tissue arrangement may facilitate the intimate involvement of seawater at the mineralization site, also documented here. We further observe an extensive filopodial network containing carbon-rich vesicles extruding from some of the calicoblastic cells. Single-cell RNA-Sequencing data interrogation supports these morphological observations by showing higher expression of genes involved in filopodia and vesicle structure and function in the calicoblastic cells. These observations provide a new conceptual framework for resolving the ion pathway from the external seawater to the tissue-mineral interface in stony coral biomineralization processes.
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Affiliation(s)
- Gal Mor Khalifa
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel; Morris Kahn Marine Research Station, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
| | - Shani Levy
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel; Morris Kahn Marine Research Station, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
| | - Tali Mass
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel; Morris Kahn Marine Research Station, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
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Marshall AT, Crewther SG. An x-ray microanalytical method for measuring in vivo element and water concentrations, relating to osmoregulation, in cells and tissues of the posterior eye. J Microsc 2021; 283:21-28. [PMID: 33605443 DOI: 10.1111/jmi.13004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 11/30/2022]
Abstract
Osmoregulation is critical for cell and tissue survival yet there are relatively few methods available to determine osmotic gradients from water and elemental concentration either in single cells or across multiple cellular layers of tissue. X-ray microanalysis of frozen-hydrated preparations in a scanning electron microscope is one such powerful, sensitive, nondestructive technique. Here we use x-ray microanalysis to quantitatively analyse intracellular element concentrations and oxygen concentrations, as a proxy for water concentrations, in selected individual cells of the posterior eye. Using frozen-hydrated preparations of the retinal complex of chicken eyes, it is shown that structural preservation is sufficient to identify cell layers and individual cells. The quantitative analysis of selected areas in the photoreceptor layer, inner nuclear layer and ganglion cell layer, where specific cell types were known to be present, provided measurements of intracellular element concentrations comparable with the analysis of individual cells. It is also shown that in the cells of the retinal pigment epithelium and outer photoreceptor segments elemental analyses were reasonably consistent at the cellular level in different depth levels of the same sample. Comparison of oxygen concentrations, as a proxy for water concentration, at two accelerating voltages (15 and 5 kV) indicated that at 15 kV oxygen concentration was largely derived from intracellular water. Water concentrations could be calculated and concentrations of diffusible elements (Na, K) could be defined in mmol/L. From the latter it is possible to calculate osmotic concentrations of individual cells and osmotic gradients across the tissue. LAY DESCRIPTION: Understanding many cellular processes, in both healthy and diseased states, depends on knowing how the water content of cells and their surrounding fluids is controlled. The transport of water is generally down its concentration gradient or against the osmotic concentration gradient defined by solutes such as sodium, potassium and chloride dissolved in the water. We have refined a microanalytical method, that detects the x-rays emitted from specific elements when they are bombarded by electrons in a scanning electron microscope, to apply it to the analysis of the retina of the eye. The method facilitates the measurement of the elemental composition, water and osmotic concentration gradients of cells and tissues in the eye, that may be involved in the development of myopia, or short sightedness, a condition that afflicts many people including some 80 - 90% of children in Asia.
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Affiliation(s)
- Alan T Marshall
- Analytical Electron Microscopy Laboratory, Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
| | - Sheila G Crewther
- Department of Psychology and Counselling, La Trobe University, Melbourne, Victoria, Australia
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Albornoz FE, Hayes PE, Orchard S, Clode PL, Nazeri NK, Standish RJ, Bending GD, Hilton S, Ryan MH. First Cryo-Scanning Electron Microscopy Images and X-Ray Microanalyses of Mucoromycotinian Fine Root Endophytes in Vascular Plants. Front Microbiol 2020; 11:2018. [PMID: 33013744 PMCID: PMC7509483 DOI: 10.3389/fmicb.2020.02018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/30/2020] [Indexed: 12/17/2022] Open
Abstract
AIMS Arbuscule-producing fine root endophytes (FRE) (previously incorrectly Glomus tenue) were recently placed within subphylum Mucoromycotina; the first report of arbuscules outside subphylum Glomeromycotina. Here, we aimed to estimate nutrient concentrations in plant and fungal structures of FRE and to test the utility of cryo-scanning electron microscopy (cryoSEM) for studying these fungi. METHODS We used replicated cryoSEM and X-ray microanalysis of heavily colonized roots of Trifolium subterraneum. RESULTS Intercellular hyphae and hyphae in developed arbuscules were consistently very thin; 1.35 ± 0.03 μm and 0.99 ± 0.03 μm in diameter, respectively (mean ± SE). Several intercellular hyphae were often adjacent to each other forming "hyphal ropes." Developed arbuscules showed higher phosphorus concentrations than senesced arbuscules and non-colonized structures. Senesced arbuscules showed greatly elevated concentrations of calcium and magnesium. CONCLUSION While uniformly thin hyphae and hyphal ropes are distinct features of FRE, the morphology of fully developed arbuscules, elevated phosphorus in fungal structures, and accumulation of calcium with loss of structural integrity in senesced arbuscules are similar to glomeromycotinian fungi. Thus, we provide evidence that FRE may respond to similar host-plant signals or that the host plant may employ a similar mechanism of association with FRE and AMF.
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Affiliation(s)
- Felipe E. Albornoz
- School of Agriculture and Environment, Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Patrick E. Hayes
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Suzanne Orchard
- School of Agriculture and Environment, Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Nazanin K. Nazeri
- School of Agriculture and Environment, Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Rachel J. Standish
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- Environmental and Conservation Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Gary D. Bending
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Sally Hilton
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Megan H. Ryan
- School of Agriculture and Environment, Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
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Hayes PE, Clode PL, Guilherme Pereira C, Lambers H. Calcium modulates leaf cell-specific phosphorus allocation in Proteaceae from south-western Australia. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3995-4009. [PMID: 31049573 PMCID: PMC6685658 DOI: 10.1093/jxb/erz156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/26/2019] [Indexed: 05/02/2023]
Abstract
Over 650 Proteaceae occur in south-western Australia, contributing to the region's exceptionally high biodiversity. Most Proteaceae occur exclusively on severely nutrient-impoverished, acidic soils (calcifuge), whilst only few also occur on young, calcareous soils (soil-indifferent), higher in calcium (Ca) and phosphorus (P). The calcifuge habit of Proteaceae is explained by Ca-enhanced P toxicity, putatively linked to the leaf cell-specific allocation of Ca and P. Separation of these elements is essential to avoid the deleterious precipitation of Ca-phosphate. We used quantitative X-ray microanalysis to determine leaf cell-specific nutrient concentrations of two calcifuge and two soil-indifferent Proteaceae grown in hydroponics at a range of Ca and P concentrations. Calcium enhanced the preferential allocation of P to palisade mesophyll (PM) cells under high P conditions, without a significant change in whole leaf [P]. Calcifuges showed a greater PM [P] compared with soil-indifferent species, corresponding to their greater sensitivity. This study advances our mechanistic understanding of Ca-enhanced P toxicity, supporting the proposed model, and demonstrating its role in the calcifuge distribution of Proteaceae. This furthers our understanding of nutrient interactions at the cellular level and highlights its importance to plant functioning.
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Affiliation(s)
- Patrick E Hayes
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
| | - Peta L Clode
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
| | - Caio Guilherme Pereira
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
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Ding W, Clode PL, Clements JC, Lambers H. Effects of calcium and its interaction with phosphorus on the nutrient status and growth of three Lupinus species. PHYSIOLOGIA PLANTARUM 2018; 163:386-398. [PMID: 29570221 DOI: 10.1111/ppl.12732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/05/2018] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
Phosphorus (P)-deficiency symptoms are known for Lupinus species grown in calcareous soil, but we do not know if this is due to a high calcium (Ca) availability or a low P availability in the soil. To address this problem, we explored both the effects of Ca and its interactions with P on nutrient status and growth of three Lupinus species. Two Ca-sensitive genotypes (L. angustifolius L. P26723 and L. cosentinii Guss. P27225) and two Ca-tolerant genotypes (L. angustifolius L. cv Mandelup and L. pilosus Murr. P27440) were grown hydroponically at two P (0.1 and 10 μM) and three Ca (0.1, 0.6 and 6 mM) levels. Leaf symptoms and biomass were recorded, whole leaf and root nutrient concentrations were analysed, and leaf cellular P and Ca concentrations were determined. Phosphorus-deficiency symptoms were only observed in the Ca-sensitive genotypes. Among all the genotypes in this study, the Ca-tolerant L. pilosus showed an ability to maintain stable leaf Ca and P concentrations whereas the Ca-tolerant L. angustifolius cv Mandelup did not maintain a stable whole leaf Ca concentration, but maintained a low cytosolic Ca2+ concentration through effective Ca compartmentation. However, the two Ca-sensitive genotypes, L. angustifolius P26723 and L. cosentinii, did not exhibit an ability to maintain a stable whole leaf Ca concentration or effectively compartmentalise Ca. Therefore, having the capacity to maintain a stable whole leaf Ca concentration or effectively compartmentalising Ca in leaves are likely critical for Lupinus species to be Ca tolerant.
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Affiliation(s)
- Wenli Ding
- School of Biological Sciences, University of Western Australia, Crawley, (Perth) WA 6009, Australia
- Institute of Agriculture, University of Western Australia, Crawley, (Perth) WA 6009, Australia
| | - Peta L Clode
- School of Biological Sciences, University of Western Australia, Crawley, (Perth) WA 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, (Perth) WA 6009, Australia
| | - Jon C Clements
- School of Biological Sciences, University of Western Australia, Crawley, (Perth) WA 6009, Australia
- Department of Primary industries and Regional Development, WA, 6000, Australia
| | - Hans Lambers
- School of Biological Sciences, University of Western Australia, Crawley, (Perth) WA 6009, Australia
- Institute of Agriculture, University of Western Australia, Crawley, (Perth) WA 6009, Australia
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Hayes PE, Clode PL, Oliveira RS, Lambers H. Proteaceae from phosphorus-impoverished habitats preferentially allocate phosphorus to photosynthetic cells: An adaptation improving phosphorus-use efficiency. PLANT, CELL & ENVIRONMENT 2018; 41:605-619. [PMID: 29314084 DOI: 10.1111/pce.13124] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/03/2017] [Indexed: 05/14/2023]
Abstract
Plants allocate nutrients to specific leaf cell types; eudicots are thought to predominantly allocate phosphorus (P) to epidermal/bundle sheath cells. However, three Proteaceae species have been shown to preferentially allocate P to mesophyll cells instead. These Proteaceae species are highly adapted to P-impoverished habitats, with exceptionally high photosynthetic P-use efficiencies (PPUE). We hypothesized that preferential allocation of P to photosynthetic mesophyll cells is an important trait in species adapted to extremely P-impoverished habitats, contributing to their high PPUE. We used elemental X-ray mapping to determine leaf cell-specific nutrient concentrations for 12 Proteaceae species, from habitats of strongly contrasting soil P concentrations, in Australia, Brazil, and Chile. We found that only species from extremely P-impoverished habitats preferentially allocated P to photosynthetic mesophyll cells, suggesting it has evolved as an adaptation to their extremely P-impoverished habitat and that it is not a family-wide trait. Our results highlight the possible role of soil P in driving the evolution of ecologically relevant nutrient allocation patterns and that these patterns cannot be generalized across families. Furthermore, preferential allocation of P to photosynthetic cells may provide new and exciting strategies to improve PPUE in crop species.
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Affiliation(s)
- Patrick E Hayes
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Peta L Clode
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Rafael S Oliveira
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, Campinas, 13083-862, Brazil
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
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Fernando DR, Marshall AT, Green PT. Cellular ion interactions in two endemic tropical rainforest species of a novel metallophytic tree genus. TREE PHYSIOLOGY 2018; 38:119-128. [PMID: 28981909 DOI: 10.1093/treephys/tpx099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
Gossia, a small genus of physiologically novel rainforest trees restricted to the Western Pacific and belonging to a key neotropical Southern Hemisphere family, the Myrtaceae, is characterized by high foliar manganese (Mn) concentrations. This field study provides a quantitative in planta snapshot detailing cellular localization of foliar Mn and other mineral nutrients in sympatric Gossia grayi N. Snow & Guymer and Gossia shepherdii N. Snow & Guymer endemic to far northeastern Australia, and previously not examined. Elements localized in the cells of fresh hydrated leaf tissues were quantified via in vivo cryo-scanning electron microscopy energy dispersive spectroscopy, a non-invasive method that effectively immobilizes cell contents. Leaf anatomical differences were found between species, along with foliar Mn spatial distribution patterns. Localized cellular Mn concentrations exceeding 600 mmol kg-1 were detected in G. shepherdii, whose Mn accumulation across different mesophyll cell types was heterogeneous compared with G. grayi. In both species there was little evidence to support previous findings on other Gossia species of carboxylate association with excess Mn. The analytical X-ray data strongly implicated chloride as a counter-ion to Mn in the two species examined here. The key findings align with the hypothesis that Mn disposal in the mesophyll is a generic trait in Gossia. This research has forged an emerging view of Gossia as being characterized by unusual cellular metal and mineral accumulation patterns that vary at the species level. It contributes to current limited knowledge about generic plant metallophyty, highlighting that assimilating a broader perspective of the phenomenon demands evaluation of individual taxa through field studies.
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Affiliation(s)
- Denise R Fernando
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, Vic 3086, Australia
| | - Alan T Marshall
- Analytical Electron Microscopy Laboratory, La Trobe University, Bundoora, Vic 3086, Australia
| | - Peter T Green
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, Vic 3086, Australia
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Marshall AT. Quantitative x-ray microanalysis of model biological samples in the SEM using remote standards and the XPP analytical model. J Microsc 2017; 266:231-238. [PMID: 28181671 DOI: 10.1111/jmi.12531] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/11/2017] [Accepted: 01/14/2017] [Indexed: 11/29/2022]
Abstract
It is shown that accurate x-ray microanalysis of frozen-hydrated and dry organic compounds, such as model biological samples, is possible with a silicon drift detector in combination with XPP (exponential model of Pouchou and Pichoir matrix correction) software using 'remote standards'. This type of analysis is also referred to as 'standardless analysis'. Analyses from selected areas or elemental images (maps) were identical. Improvements in x-ray microanalytical hardware and software, together with developments in cryotechniques, have made the quantitative analysis of cryoplaned frozen-hydrated biological samples in the scanning electron microscope a much simpler procedure. The increased effectiveness of pulse pile-up rejection renders the analysis of Na, with ultrathin window detectors, in the presence of very high concentrations of O, from ice, more accurate. The accurate analysis of Ca (2 mmol kg-1 ) in the presence of high concentrations of K is possible. Careful sublimation of surface frost from frozen-hydrated samples resulted in a small increase in analysed elemental concentrations. A more prolonged sublimation from the same resurfaced sample and other similar samples resulted in higher element concentrations.
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Affiliation(s)
- Alan T Marshall
- Analytical Electron Microscopy Laboratory, Department of Ecology,Environment and Evolution, La Trobe University, Melbourne, Victoria, 3086, Australia
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Chen S, Diekmann H, Janz D, Polle A. Quantitative X-ray Elemental Imaging in Plant Materials at the Subcellular Level with a Transmission Electron Microscope: Applications and Limitations. MATERIALS (BASEL, SWITZERLAND) 2014; 7:3160-3175. [PMID: 28788612 PMCID: PMC5453366 DOI: 10.3390/ma7043160] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/10/2014] [Accepted: 04/11/2014] [Indexed: 11/22/2022]
Abstract
Energy-dispersive X-ray microanalysis (EDX) is a technique for determining the distribution of elements in various materials. Here, we report a protocol for high-spatial-resolution X-ray elemental imaging and quantification in plant tissues at subcellular levels with a scanning transmission electron microscope (STEM). Calibration standards were established by producing agar blocks loaded with increasing KCl or NaCl concentrations. TEM-EDX images showed that the salts were evenly distributed in the agar matrix, but tended to aggregate at high concentrations. The mean intensities of K⁺, Cl-, and Na⁺ derived from elemental images were linearly correlated to the concentrations of these elements in the agar, over the entire concentration range tested (R > 0.916). We applied this method to plant root tissues. X-ray images were acquired at an actual resolution of 50 nm ´ 50 nm to 100 nm ´ 100 nm. We found that cell walls exhibited higher elemental concentrations than vacuoles. Plants exposed to salt stress showed dramatic accumulation of Na⁺ and Cl- in the transport tissues, and reached levels similar to those applied in the external solution (300 mM). The advantage of TEM-EDX mapping was the high-spatial-resolution achieved for imaging elemental distributions in a particular area with simultaneous quantitative analyses of multiple target elements.
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Affiliation(s)
- Shaoliang Chen
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.
| | - Heike Diekmann
- Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Göttingen 37077, Germany.
| | - Dennis Janz
- Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Göttingen 37077, Germany.
| | - Andrea Polle
- Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Göttingen 37077, Germany.
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Fernando DR, Marshall A, Baker AJM, Mizuno T. Microbeam methodologies as powerful tools in manganese hyperaccumulation research: present status and future directions. FRONTIERS IN PLANT SCIENCE 2013; 4:319. [PMID: 23970891 PMCID: PMC3747628 DOI: 10.3389/fpls.2013.00319] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 07/29/2013] [Indexed: 05/12/2023]
Abstract
Microbeam studies over the past decade have garnered unique insight into manganese (Mn) homeostasis in plant species that hyperaccumulate this essential mineral micronutrient. Electron- and/or proton-probe methodologies employed to examine tissue elemental distributions have proven highly effective in illuminating excess foliar Mn disposal strategies, some apparently unique to Mn hyperaccumulating plants. When applied to samples prepared with minimal artefacts, these are powerful tools for extracting true 'snapshot' data of living systems. For a range of reasons, Mn hyperaccumulation is particularly suited to in vivo interrogation by this approach. Whilst microbeam investigation of metallophytes is well documented, certain methods originally intended for non-biological samples are now widely applied in biology. This review examines current knowledge about Mn hyperaccumulators with reference to microbeam methodologies, and discusses implications for future research into metal transporters.
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Affiliation(s)
| | - Alan Marshall
- Analytical Electron Microscopy Facility, La Trobe UniversityBundoora, VIC, Australia
| | - Alan J. M. Baker
- School of Botany, The University of MelbourneParkville, VIC, Australia
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MARSHALL ALANT, GOODYEAR MELINDAJ, CREWTHER SHEILAG. Sequential quantitative X-ray elemental imaging of frozen-hydrated and freeze-dried biological bulk samples in the SEM. J Microsc 2011; 245:17-25. [DOI: 10.1111/j.1365-2818.2011.03539.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Marshall AT, Clode PL. X-ray microanalysis of Rb+ entry into cricket Malpighian tubule cells via putative K+ channels. J Exp Biol 2009; 212:2977-82. [DOI: 10.1242/jeb.032177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
SUMMARY
Elemental imaging by X-ray microanalysis of fully frozen-hydrated samples shows that when Malpighian tubules of the black field cricket(Teleogryllus oceanicus L.) are incubated in saline in which Rb+ has been substituted for K+, Rb+ replaces much of the cellular K+ in the main segment of control Malpighian tubules and this is prevented by incubation in saline containing Ba2+, a non-selective K+ channel blocker. Similarly the amount of cellular K+ is greatly reduced when tubules incubated in normal, i.e. K+ containing, saline are exposed to Ba2+. By considering the amounts of cellular K and Rb remaining in the main segments of tubules incubated in either K+ containing saline or Rb+ containing saline after Ba+ treatment, it is suggested that: (a) a major part (56%) of cellular K+ enters by Ba2+ sensitive K+ channels and that Rb+ can also enter by this route; (b) a smaller fraction (26%) of cellular K+ enters by a previously proposed Na+/K+/2Cl– co-transporter, which can also transport Rb+; (c) a previously proposed Na+/K+-ATPase is responsible for maintaining a K+ pool (18%) in the tubule cells that is not exchangeable by Rb+; and (d) entry by this Na+/K+-ATPase is not available to Rb+.
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Affiliation(s)
- Alan T. Marshall
- Department of Zoology and Analytical Electron Microscopy Laboratory, Faculty of Science, Technology and Engineering, La Trobe University, Melbourne, VIC 3086, Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009, Australia
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Rokitta M, Medek D, Pope JM, Critchley C. 23Na NMR microimaging: a tool for non-invasive monitoring of sodium distribution in living plants. FUNCTIONAL PLANT BIOLOGY : FPB 2004; 31:879-887. [PMID: 32688956 DOI: 10.1071/fp04063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/05/2004] [Indexed: 06/11/2023]
Abstract
Detailed knowledge of the sodium (Na) distribution within the tissues of highly salt-tolerant Australian native species could help in understanding the physiological adaptations of salt-tolerance or salt-sensitive plants. 23Na nuclear magnetic resonance (NMR) microimaging is presented as a tool to achieve this goal. Maps of the Na distribution in stem tissue were obtained with an in-plane resolution of approximately125 µm and a slice thickness of 4 mm. Simultaneously recorded high resolution 1H NMR images showing water distribution in the same slice with 31 µm in-plane resolution and 1 mm slice thickness, were used as an anatomical reference together with optical micrographs that were taken immediately after the NMR experiments were completed. To quantify the Na concentration, reference capillaries with known NaCl concentrations were located in the NMR probe together with the plant sample. Average concentration values calculated from signal intensities in the tissue and the capillaries were compared with concentration values obtained from atomic emission photometry and optical microscopy performed on digested stem sections harvested immediately after NMR experiments. Results showed that 23Na NMR microimaging has great potential for physiological studies of salt stress at the macroscopic level, and may become a unique tool for diagnosing salt tolerance and sensitivity.
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Affiliation(s)
- Markus Rokitta
- Department of Botany, The University of Queensland, St. Lucia, Qld 4072, Australia
| | - Danielle Medek
- Department of Botany, The University of Queensland, St. Lucia, Qld 4072, Australia
| | - James M Pope
- School of Physical and Chemical Sciences, Queensland University of Technology, Gardens Point, Qld 4001, Australia
| | - Christa Critchley
- Department of Botany, The University of Queensland, St. Lucia, Qld 4072, Australia
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Clode PL, Marshall AT. Low temperature X-ray microanalysis of calcium in a scleractinian coral:evidence of active transport mechanisms. J Exp Biol 2002; 205:3543-52. [PMID: 12364407 DOI: 10.1242/jeb.205.22.3543] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Element concentrations were measured by X-ray microanalysis in seawater(SW) compartments and mucocytes in bulk, frozen-hydrated preparations of the scleractinian coral Galaxea fascicularis. Quantitative X-ray microanalysis of polyps sampled in the daytime revealed that concentrations of the elements Na, S, K and Ca were all significantly higher in a thin (10-20μm) external SW layer adjacent to the oral ectoderm (P<0.05,<0.05, <0.0001 and <0.01, respectively) than in standard SW. In polyps sampled during night-time, concentrations of Ca and S in this external SW layer were significantly reduced (P<0.05). Ca concentration in the coelenteron and extrathecal coelenteron was significantly higher(P<0.001) than in the external SW layer, regardless of time of sampling, suggesting that Ca2+ transport across the oral epithelium occurs via an active, transcellular route. X-ray microanalyses of mucocytes revealed that the concentration of S was high and did not vary between epithelial layers, while that of Ca increased in an inward gradient toward the skeleton. We suggest that throughout the day, secreted mucus behaves as a Donnan matrix at the oral ectoderm—SW interface,facilitating intracellular Ca2+ uptake. The accumulation within internal SW compartments of high concentrations of Ca relative to standard SW levels, however, appears to be independent of mucus secretion and is likely to be a consequence of active transport processes.
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Affiliation(s)
- Peta L Clode
- Analytical Electron Microscopy Laboratory, Department of Zoology, La Trobe University, Bundoora, Melbourne, Victoria, 3083, Australia
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15
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Xu W, Marshall AT. Control of ion and fluid transport by putative second messengers in different segments of the Malpighian tubules of the black field cricket Teleogryllus oceanicus. JOURNAL OF INSECT PHYSIOLOGY 2000; 46:21-31. [PMID: 12770255 DOI: 10.1016/s0022-1910(99)00097-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The differences in second messenger control of secretion were investigated in the distal and main segments of the Malpighian tubules of the black field cricket Teleogryllus oceanicus. Secretion by the main segment was considerably increased by corpora cardiaca extract and db-cAMP. Corpora cardiaca had no effect on secreted fluid composition or intracellular elemental composition but db-cAMP increased Na(+) and Cl(-) transport, as measured by x-ray microanalysis of secreted fluids and cells. Secretion by the main segment was considerably increased by forskolin and by Sp-cAMP. Secretion in the distal segment was abolished by corpora cardiaca extract but was unaffected by db-cAMP and only slightly reduced by 8-bromo-cAMP. However, Sp-cAMP increased secretion but forskolin reduced secretion. The responses of the distal segment suggest the possibility of a multiplicity of controls through different protein kinases and adenylyl cyclases. Secretion rate in the main segment was also increased by cGMP but distal segment secretion was unaffected. Secretion from both segments was increased by 5-HT. In the main segment secretion rate was increased by Ca-ionophore and thapsigargin and decreased by verapamil. This suggests a role for Ca(2+) as a controlling second messenger. In the distal segment only Ca-ionophore had an effect on secretion rate, which was reduced. Secretion rates in both segments were decreased in Ca-free saline. In saline in which Sr(2+) replaced Ca(2+), secretion rate in the main segment was greatly increased whilst that of the distal segment was decreased, suggesting that Sr(2+) could substitute for Ca(2+) as a second messenger.
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Affiliation(s)
- W Xu
- Analytical Electron Microscopy Laboratory, Department of Zoology, La Trobe University, Bundoora (Melbourne), Victoria, Australia
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16
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Xu W, Marshall AT. X-ray microanalysis of the Malpighian tubules of the black field cricket Teleogryllus oceanicus: the roles of Na K ATPase and the Na K 2Cl cotransporter. JOURNAL OF INSECT PHYSIOLOGY 1999; 45:885-893. [PMID: 12770281 DOI: 10.1016/s0022-1910(99)00063-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Both main and distal segments of the Malpighian tubules were sensitive to ouabain and furosemide but in different ways. Oubain had no effect on secretion rate by the main segment but in the secreted fluid Na(+) concentration increased substantially whereas K(+) decreased. Similarly intracellular elemental Na concentration increased and K decreased. Furosemide decreased the secretion rate of the main segment by 80%. The Na(+) concentration in the secreted fluid increased markedly but K(+) was not affected. Intracellular elemental Na concentration also increased but K was unchanged. In the distal segments both ouabain and furosemide decreased secretion rate by 40% but although ouabain had no effect on the composition of the secreted fluid, furosemide caused a substantial reduction in the concentrations of Mg(2+) and Cl(-) and a substantial increase in Na(+) and K(+) concentrations. The evidence suggests that the main segment contains a Na K ATPase and possibly a Na K 2Cl cotransporter whereas the distal segment may contain a Na K ATPase and a furosemide sensitive Mg(2+) transporter. K(+) entry into the cells of the main segment may be partially effected by a Na K 2Cl cotransporter but may be primarily via Na K ATPase in the distal segment.
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Affiliation(s)
- W Xu
- Analytical Electron Microscopy Laboratory, Department of Zoology, La Trobe University, Bundoora, Melbourne, Australia
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17
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Marshall AT, Xu W. Use of Rb(+) and Br(-) as tracers for investigating ion transport by X-ray microanalysis in the Malpighian tubules of the black field cricket Teleogryllus oceanicus. JOURNAL OF INSECT PHYSIOLOGY 1999; 45:265-273. [PMID: 12770374 DOI: 10.1016/s0022-1910(98)00122-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Substitution of Rb(+) for K(+) in the incubation saline for in vitro preparations of Malpighian tubules had little effect on tubule function. Secretion rates increased by 10% for whole tubules, 9% for distal segments and 10% for main segments. In the secreted fluids Rb(+) almost completely replaced K(+). Within the cells of the main segment of the tubules Rb replaced the majority of the intracellular K. Treatment by ouabain in Rb saline resulted in a considerable increase in intracellular Na and Cl concentrations but no change in Rb concentration. This suggests that Rb(+) did not enter the cell via Na K ATPase and that the latter was not directly involved in Rb(+) secretion and by inference K(+) secretion. Substitution of Br(-) for Cl(-) in the incubation saline resulted in a 30% reduction in secretion rate from the distal segments but only a 10% reduction for the main segment. Cl(-) was almost completely replaced by Br(-) in fluid from both main and distal segments. In cells of the main segment the intracellular concentration of Br(-) did not exceed 30mmol kg(-1) dry weight and the Cl(-) concentration was unchanged in the apical region of the cell and increased in the basal region. These data suggest that Br(-) was transported across the tubule epithelium by a paracellular route and that the basal cell membrane is relatively impermeable to Cl(-). By inference Cl(-) may also be transported by a paracellular route.
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Affiliation(s)
- A T. Marshall
- Analytical Electron Microscopy Laboratory, Department of Zoology, La Trobe University, Bundoora, (Melbourne), Australia
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