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Joseph A M Holtum - One of the best experts on this subject based on the ideXlab platform.
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facultative crassulacean acid metabolism in a c3 c4 intermediate
Journal of Experimental Botany, 2019Co-Authors: Klaus Winter, Joseph A M Holtum, Rowan F Sage, Erika J Edwards, Aurelio VirgoAbstract:The Portulacaceae enable the study of the evolutionary relationship between C4 and crassulacean acid metabolism (CAM) photosynthesis. Shoots of well-watered plants of the C3-C4 intermediate species Portulaca cryptopetala Speg. exhibit net uptake of CO2 solely during the light. CO2 fixation is primarily via the C3 pathway as indicated by a strong stimulation of CO2 uptake when shoots were provided with air containing 2% O2. When plants were subjected to water stress, daytime CO2 uptake was reduced and CAM-type net CO2 uptake in the dark occurred. This was accompanied by nocturnal accumulation of acid in both leaves and stems, also a defining characteristic of CAM. Following rewatering, net CO2 uptake in the dark ceased in shoots, as did nocturnal acidification of the leaves and stems. With this unequivocal demonstration of stress-related reversible, i.e. facultative, induction of CAM, P. cryptopetala becomes the first C3-C4 intermediate species reported to exhibit CAM. Portulaca molokiniensis Hobdy, a C4 species, also exhibited CAM only when subjected to water stress. Facultative CAM has now been demonstrated in all investigated species of Portulaca, which are well sampled from across the phylogeny. This strongly suggests that in Portulaca, a lineage in which species engage predominately in C4 photosynthesis, facultative CAM is ancestral to C4. In a broader context, it has now been demonstrated that CAM can co-exist in leaves that exhibit any of the other types of photosynthesis known in terrestrial plants: C3, C4 and C3-C4 intermediate.
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optional use of cam photosynthesis in two c4 species Portulaca cyclophylla and Portulaca digyna
Journal of Plant Physiology, 2017Co-Authors: Joseph A M Holtum, Erika J Edwards, Lillian P Hancock, Klaus WinterAbstract:Low levels of crassulacean acid metabolism (CAM) are demonstrated in two species with C4 photosynthesis, Portulaca cyclophylla and P. digyna. The expression of CAM in P. cyclophylla and P. digyna is facultative, i.e. optional. Well-watered plants did not accumulate acid at night and exhibited gas-exchange patterns consistent with C4 photosynthesis. CAM-type nocturnal acidification was reversible in that it was induced following drought and lost when droughted plants were rewatered. In P. cyclophylla, droughting was accompanied by a small but discernible net uptake of CO2 during the dark, whereas in P. digyna, net CO2 exchange at night approached the CO2 compensation point but did not transition beyond it. This report brings the number of known C4 species with a capacity for expressing CAM to six. All are species of Portulaca. The observation of CAM in P. cyclophylla and P. digyna is the first for species in the opposite-leaved (OL) Portulacelloid-anatomy lineage of Portulaca and for the Australian clade therein. The other four species are within the alternate-leaved (AL) lineage, in the Atriploid-anatomy Oleracea and the Pilosoid-anatomy Pilosa clades. Studies of the evolutionary origins of C4 and CAM in Portulaca will benefit from a more wide-range survey of CAM across its species, particularly in the C3-C4 intermediate-containing Cryptopetala clade.
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facultative crassulacean acid metabolism cam in four small c3 and c4 leaf succulents
Australian Journal of Botany, 2017Co-Authors: Klaus Winter, Joseph A M HoltumAbstract:Measurements of whole-plant gas exchange and titratable acidity demonstrate that the Australian native species Anacampseros australiana J.M.Black (Anacampserotaceae), Crassula sieberiana (Schult. & Schult.f.) Druce (Crassulaceae) and Portulaca australis Endl. (Portulacaceae) and the widespread naturalised tropical exotic, Portulaca pilosa L., exhibit facultative crassulacean acid metabolism (CAM). In well-watered plants, net CO2 uptake was restricted to the daylight hours and occurred via the C-3 pathway (A. australiana and C. sieberiana) or the C-4 pathway (P. australis and P. pilosa). Leaves of well-watered plants did not accumulate titratable acidity during the night. Following drought treatment, CO2 uptake in the light by shoots decreased markedly, nocturnal gas-exchange shifted from net CO2 loss to a CAM-type pattern that included net CO2 uptake, and leaves acidified at night. Nocturnal CO2 uptake by shoots and leaf acidification were most pronounced in A. australiana and least so in C. sieberiana. The induction of dark CO2 uptake and tissue acidification was fully reversible in all four species: upon rewatering, nocturnal CO2 uptake and acidification ceased and the rates of CO2 incorporation in the light were restored. Wesuggest that, hitherto considered relatively exceptional globally, facultative CAM may be more common than previously suspected, particularly among the generally small ephemeral leaf-succulents that characterise Australia's succulent flora.
Pascalantoine Christin - One of the best experts on this subject based on the ideXlab platform.
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shared origins of a key enzyme during the evolution of c4 and cam metabolism
Journal of Experimental Botany, 2014Co-Authors: Julian M Hibberd, Rowan F Sage, Pascalantoine Christin, Monica Arakaki, Colin P Osborne, Andrea Brautigam, Steven L Kelly, Sarah CovshoffAbstract:CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
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shared origins of a key enzyme during the evolution of c4 and cam metabolism
Journal of Experimental Botany, 2014Co-Authors: Pascalantoine Christin, Monica Arakaki, Colin P Osborne, Andrea BrautigamAbstract:CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
Rowan F Sage - One of the best experts on this subject based on the ideXlab platform.
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facultative crassulacean acid metabolism in a c3 c4 intermediate
Journal of Experimental Botany, 2019Co-Authors: Klaus Winter, Joseph A M Holtum, Rowan F Sage, Erika J Edwards, Aurelio VirgoAbstract:The Portulacaceae enable the study of the evolutionary relationship between C4 and crassulacean acid metabolism (CAM) photosynthesis. Shoots of well-watered plants of the C3-C4 intermediate species Portulaca cryptopetala Speg. exhibit net uptake of CO2 solely during the light. CO2 fixation is primarily via the C3 pathway as indicated by a strong stimulation of CO2 uptake when shoots were provided with air containing 2% O2. When plants were subjected to water stress, daytime CO2 uptake was reduced and CAM-type net CO2 uptake in the dark occurred. This was accompanied by nocturnal accumulation of acid in both leaves and stems, also a defining characteristic of CAM. Following rewatering, net CO2 uptake in the dark ceased in shoots, as did nocturnal acidification of the leaves and stems. With this unequivocal demonstration of stress-related reversible, i.e. facultative, induction of CAM, P. cryptopetala becomes the first C3-C4 intermediate species reported to exhibit CAM. Portulaca molokiniensis Hobdy, a C4 species, also exhibited CAM only when subjected to water stress. Facultative CAM has now been demonstrated in all investigated species of Portulaca, which are well sampled from across the phylogeny. This strongly suggests that in Portulaca, a lineage in which species engage predominately in C4 photosynthesis, facultative CAM is ancestral to C4. In a broader context, it has now been demonstrated that CAM can co-exist in leaves that exhibit any of the other types of photosynthesis known in terrestrial plants: C3, C4 and C3-C4 intermediate.
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shared origins of a key enzyme during the evolution of c4 and cam metabolism
Journal of Experimental Botany, 2014Co-Authors: Julian M Hibberd, Rowan F Sage, Pascalantoine Christin, Monica Arakaki, Colin P Osborne, Andrea Brautigam, Steven L Kelly, Sarah CovshoffAbstract:CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
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evolutionary physiology the extent of c4 and cam photosynthesis in the genera anacampseros and grahamia of the Portulacaceae
Journal of Experimental Botany, 2007Co-Authors: Lonnie J Guralnick, Amanda Cline, Monica Smith, Rowan F SageAbstract:The Portulacaceae is one of the few terrestrial plant families known to have both C4 and Crassulacean acid metabolism (CAM) species. There may be multiple origins of the evolution of CAM within the Portulacaceae but the only clear evidence of C4 photosynthesis is found in members of the genus Portulaca. In the Portulaca, CAM succulent tissue is overlaid with the C4 tissue in a unique fashion where both pathways are operating simultaneously. Earlier reports have shown that the clade containing the genera Anacampseros and Grahamia may also contain C4 photosynthetic species similar to the Portulaca, which would indicate multiple origins of C4 photosynthesis within the family. The aim of the present study was to ascertain the true photosynthetic nature of these genera. An initial survey of the carbon isotope composition of the Anacampseros ranged from –12.6& to –24.0&, indicating very little CAM activity in some species, with other values close to the C4 range. Anacampseros (¼Grahamia) australiana which had been previously identified as a C4 species had a carbon isotope composition value of –24.0&, which is more indicative of a C3 species with a slight contribution of CAM activity. Other Anacampseros species with C4-like values have been shown to be CAM plants. The initial isotope analysis of the Grahamia species gave values in the range of –27.1& to –23.6&, placing the Grahamia species well towards the C3 photosynthetic range. Further physiological studies indicated increased night-time CO2 uptake with imposition of water stress, associated with a large diurnal acid fluctuation and a marked increased phosphoenolpyruvate carboxylase activity. This showed that the Grahamia species are actually facultative CAM plants despite their C3-like carbon isotope values. The results indicate that the Grahamia and Anacampseros species do not utilize the C4 photosynthetic pathway. This is the first to identify that the Grahamia species are facultative CAM plants where CAM can be induced by water stress. This work supports earlier physiological work that indicates that this clade containing Anacampseros and Grahamia species comprises predominantly facultative CAM plants. This report suggests there may be only one clade which contains C4 photosynthetic members with CAM-like characteristics.
Monica Arakaki - One of the best experts on this subject based on the ideXlab platform.
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shared origins of a key enzyme during the evolution of c4 and cam metabolism
Journal of Experimental Botany, 2014Co-Authors: Julian M Hibberd, Rowan F Sage, Pascalantoine Christin, Monica Arakaki, Colin P Osborne, Andrea Brautigam, Steven L Kelly, Sarah CovshoffAbstract:CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
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shared origins of a key enzyme during the evolution of c4 and cam metabolism
Journal of Experimental Botany, 2014Co-Authors: Pascalantoine Christin, Monica Arakaki, Colin P Osborne, Andrea BrautigamAbstract:CAM and C4 photosynthesis are two key plant adaptations that have evolved independently multiple times, and are especially prevalent in particular groups of plants, including the Caryophyllales. We investigate the origin of photosynthetic PEPC, a key enzyme of both the CAM and C4 pathways. We combine phylogenetic analyses of genes encoding PEPC with analyses of RNA sequence data of Portulaca, the only plants known to perform both CAM and C4 photosynthesis. Three distinct gene lineages encoding PEPC exist in eudicots (namely ppc-1E1, ppc-1E2 and ppc-2), one of which (ppc-1E1) was recurrently recruited for use in both CAM and C4 photosynthesis within the Caryophyllales. This gene is present in multiple copies in the cacti and relatives, including Portulaca. The PEPC involved in the CAM and C4 cycles of Portulaca are encoded by closely related yet distinct genes. The CAM-specific gene is similar to genes from related CAM taxa, suggesting that CAM has evolved before C4 in these species. The similar origin of PEPC and other genes involved in the CAM and C4 cycles highlights the shared early steps of evolutionary trajectories towards CAM and C4, which probably diverged irreversibly only during the optimization of CAM and C4 phenotypes.
Xixiang Ying - One of the best experts on this subject based on the ideXlab platform.
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a trace alkaloid oleraisoindole a from Portulaca oleracea l and its anticholinesterase effect
Natural Product Research, 2021Co-Authors: Wenjie Zhang, Xixiang Ying, Didier StienAbstract:A new trace alkaloid possessing the lignan structure, named oleraisoindole A, was obtained from the extract of the Portulaca oleracea L.. The structure of oleraisoindole A was elucidated by 1D and ...
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An isoindole alkaloid from Portulaca oleracea L.
Natural Product Research, 2018Co-Authors: Mingyue Jiang, Wenjie Zhang, Xixiang Ying, Xu Yang, Fen Xiu, Didier StienAbstract:A novel isoindole alkaloid named oleraisoindole (1), together with six known compounds, 7′-ethoxy-trans-feruloyltyramine (2), N-trans-feruloyltyramine (3), N-trans-feruloyl-3-methoxytyramine (4), N-trans-p-coumaroyltyramine (5) aurantiamide (6) and ferulic acid methyl ester (7) were isolated from Portulaca oleracea L. Compounds 2 and 7 were isolated for the first time from this plant. Compound 1 was identified using spectroscopic methods including HR-ESI-TOF-MS, 1D-NMR, 2D-NMR. It was tested in a nitric oxide (NO) inhibition assay and was shown to inhibit NO production in RAW 264.7 cells induced by LPS.
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a novel alkaloid from Portulaca oleracea l
Natural Product Research, 2017Co-Authors: Zheming Ying, Wenjuan Wei, Dong Hao, Wenjie Zhang, Xixiang Ying, Mingyue Jiang, Haibo Wang, Jing LiuAbstract:A novel alkaloid named oleraciamide C (1), with six known compounds, hydroxydihydrobovolide (2), uracil (3), catechol (4), 4-aminophenol (5), vanillic acid (6) as well as 3-hydroxypyridine (7), were isolated from Portulaca oleracea L. Additionally, hydroxydihydrobovolide (2), 4-aminophenol (5), 3-hydroxypyridine (7) were obtained from the plant for the first time. Structure of the new compound was determined using spectroscopic methods including HR-ESI-TOF-MS, 1D and 2D NMR. Others were elucidated through 1H NMR, 13C NMR spectra and comparison with literature data. Notably, Compound 1 possessed an unusual bis-substituted eight-membered ring linked with the β-glucopyranose moiety. The cytotoxicity of compound 1 was evaluated against human adipose-derived stem cells (hADSCs) by CCK-8 method.
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two new similar alkaloids from Portulaca oleracea l
Natural Product Research, 2017Co-Authors: Zheming Ying, Mingzhe Gao, Wenjuan Wei, Dong Hao, Xiaojun Tao, Wenjie Zhang, Xixiang Ying, Jing LiuAbstract:Two novel alkaloids named oleraciamide A (1) and oleraciamide B (2) were isolated from Portulaca oleracea L., and spectroscopic methods including 1D and 2D nuclear magnetic resonance and high-resolution electrospray ionisation quadrupole-time of flight mass spectrometer spectrometry techniques are employed to determine their structures. Oleraciamide A (1) was evaluated no cytotoxicity at concentrations up to 80 μM over 72 h against human adipose-derived stem cells (hADSCs) by CCK-8 method.
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correction to three novel alkaloids from Portulaca oleracea l and their anti inflammatory effects
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Yihan Meng, Zheming Ying, Mingzhe Gao, Dong Hao, Wenjie Zhang, Didier Stien, Yucong Gao, Xixiang YingAbstract:Oleracimine and oleracimine A were isolated from Portulaca oleracea L. and described in the J. Agric. Food Chem, but the alternative structures of the two compounds are proposed on the basis of NMR analyses.