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Vincent R Franceschi - One of the best experts on this subject based on the ideXlab platform.
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calcium channels are involved in calcium oxalate crystal formation in specialized cells of pistia stratiotes l
Annals of Botany, 2004Co-Authors: Gayle M Volk, Lenora J Goss, Vincent R FranceschiAbstract:Background and aims Pistia stratiotes produces large amounts of calcium (Ca) oxalate crystals in specialized cells called crystal Idioblasts. The potential involvement of Ca(2+) channels in Ca oxalate crystal formation by crystal Idioblasts was investigated. Methods Anatomical, ultrastructural and physiological analyses were used on plants, fresh or fixed tissues, or protoplasts. Ca(2+) uptake by protoplasts was measured with (45)Ca(2+), and the effect of Ca(2+) channel blockers studied in intact plants. Labelled Ca(2+) channel blockers and a channel protein antibody were used to determine if Ca(2+) channels were associated with crystal Idioblasts. Key results (45)Ca(2+) uptake was more than two orders of magnitude greater for crystal Idioblast protoplasts than mesophyll protoplasts, and Idioblast number increased when medium Ca was increased. Plants grown on media containing 1-50 microM of the Ca(2+) channel blockers, isradipine, nifedipine or fluspirilene, showed almost complete inhibition of crystal formation. When fresh tissue sections were treated with the fluorescent dihydropyridine-type Ca(2+) channel blocker, DM-Bodipy-DHP, crystal Idioblasts were intensely labelled compared with surrounding mesophyll, and the label appeared to be associated with the plasma membrane and the endoplasmic reticulum, which is shown to be abundant in Idioblasts. An antibody to a mammalian Ca(2+) channel alpha1 subunit recognized a single band in a microsomal protein fraction but not soluble protein fraction on western blots, and it selectively and heavily labelled developing crystal Idioblasts in tissue sections. Conclusions The results demonstrate that Ca oxalate crystal Idioblasts are enriched, relative to mesophyll cells, in dihydropyridine-type Ca(2+) channels and that the activity of these channels is important to transport and accumulation of Ca(2+) required for crystal formation.
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calcium oxalate formation in lemna minor physiological and ultrastructural aspects of high capacity calcium sequestration
New Phytologist, 2004Co-Authors: A M A Mazen, Dianzhong Zhang, Vincent R FranceschiAbstract:Summary • The function of calcium oxalate (CaOx) raphide crystal formation, and structural features related to regulation of crystal formation, were studied in Lemna minor fronds using physiological and microscopy techniques. • Specialized crystal-forming cells (crystal Idioblasts) increased in number and size; CaOx, but not soluble oxalate, increased in response to increasing calcium in the growth medium. Size and number of Idioblasts had a distinct upper limit. • The CaOx crystals are formed in membranous ‘chambers’ and connected in rows by parallel membrane sheets, both forming de novo in the vacuole. The chambers, but not parallel membranes, had calcium associated with them. A calcium-binding matrix protein was associated with Idioblast vacuoles and crystal formation. • Lemna crystal Idioblasts function as calcium-inducible, specialized high-capacity but saturable sinks for bulk regulation of calcium, and crystal deposition is a highly controlled process requiring intravacuolar membrane systems and calcium-binding organic matrix materials.
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the role of druse and raphide calcium oxalate crystals in tissue calcium regulation in pistia stratiotes leaves
Plant Biology, 2002Co-Authors: Gayle M Volk, V J Lynchholm, T A Kostman, L J Goss, Vincent R FranceschiAbstract:Abstract: Ca oxalate crystal formation was examined in Pistia stratiotes L. leaves during excess Ca and Ca-deficient conditions. Pistia produces druse crystal Idioblasts in the adaxial mesophyll and raphide Idioblasts in the abaxial aerenchyma. Raphide crystals were previously found to grow bidirectionally, and here we show that Ca is incorporated along the entire surfaces of developing druse crystals, which are coated with membrane-bound microprojections. Leaves formed on plants grown on 0 Ca medium have fewer and smaller druse crystals than leaves formed under 5 mM Ca (“control”) conditions, while raphide crystal formation is completely inhibited. When plants were moved from 0 to 15 mM (“high”) Ca, the size and number of crystals in new leaves returned to (druse) or exceeded (raphide) control levels. High Ca also induced formation of druse, but not raphide, crystals in differentiating chlorenchyma cells. When plants were transferred from 15 mM Ca to 0 Ca, young druse crystals were preferentially partially dissolved. Oxalate oxidase, an enzyme that degrades oxalate, increased during Ca deficiency and was localized to the crystal surfaces. The more dynamic nature of druse crystals is not due to hydration form as both crystal types are shown to be monohydrate. Part of the difference may be because raphide Idioblasts have developmental constraints that interfere with a more flexible response to changing Ca. These studies demonstrate that excess Ca can be stored as Ca oxalate, the Ca can be remobilized under certain conditions, and different forms of Ca oxalate have different roles in bulk Ca regulation.
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l ascorbic acid and l galactose are sources for oxalic acid and calcium oxalate in pistia stratiotes
Phytochemistry, 2000Co-Authors: Sarah E Keates, Nathan M Tarlyn, Frank A Loewus, Vincent R FranceschiAbstract:Abstract Axenic Pistia stratiotes L. plants were pulse-chase labeled with [ 14 C ]oxalic acid, L -[1- 14 C ]ascorbic acid, L -[6- 14 C ]ascorbic acid, D -[1- 14 C ]erythorbic acid, L -[1- 14 C ]galactose, or [1- 14 C ]glycolate. Specific radioactivities of L -ascorbic acid (AsA), free oxalic acid (OxA) and calcium oxalate (CaOx) in labeled plants were compared. Samples of leaf tissue were fixed for microautoradiography and examined by confocal microscopy. Results demonstrate a biosynthetic role for AsA as precursor of OxA and its crystalline deposition product, CaOx, in Idioblast cells of P. stratiotes and support the recent discovery of Wheeler, Jones and Smirnoff ( Wheeler, G.L., Jones M.A., & Smirnoff, N. (1998) . The biosynthetic pathway of vitamin C in higher plants. Nature , 393, 365–369) that L -galactose is a key intermediate in the conversion of D -glucose to AsA in plants. D -[1- 14 C ]Erythorbic acid (a diastereomeric analog of AsA) is utilized also by P. stratiotes as a precursor of OxA and its calcium salt deposition product in Idioblasts. Labeled OxA is rapidly incorporated into CaOx in Idioblasts, but microautoradiography shows there is also significant incorporation of carbon from OxA into other components of growing cells, contrary to the dogma that OxA is a relatively stable end product of metabolism. Glycolate is a poor substrate for synthesis of OxA and CaOx formation, further establishing AsA as the immediate precursor in the synthesis of OxA used for calcium precipitation in crystal Idioblasts.
Rocio Diaz I De La Garza - One of the best experts on this subject based on the ideXlab platform.
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avocado fruit maturation and ripening dynamics of aliphatic acetogenins and lipidomic profiles from mesocarp Idioblasts and seed
BMC Plant Biology, 2017Co-Authors: Carlos Eduardo Rodriguezlopez, Carmen Hernandezbrenes, Victor Trevino, Rocio Diaz I De La GarzaAbstract:Avocado fruit contains aliphatic acetogenins (oft-acetylated, odd-chain fatty alcohols) with promising bioactivities for both medical and food industries. However, we have scarce knowledge about their metabolism. The present work aimed to study changes in acetogenin profiles from mesocarp, lipid-containing Idioblasts, and seeds from ‘Hass’ cultivar during fruit development, germination, and three harvesting years. An untargeted LC-MS based lipidomic analysis was also conducted to profile the lipidome of avocado fruit in each tissue. The targeted analysis showed that acetogenin profiles and contents remained unchanged in avocado mesocarp during maturation and postharvest ripening, germination, and different harvesting years. However, a shift in the acetogenin profile distribution, accompanied with a sharp increase in concentration, was observed in seed during early maturation. Untargeted lipidomics showed that this shift was accompanied with remodeling of glycerolipids: TAGs and DAGs decreased during fruit growing in seed. Remarkably, the majority of the lipidome in mature seed was composed by acetogenins; we suggest that this tissue is able to synthesize them independently from mesocarp. On the other hand, lipid-containing Idioblasts accumulated almost the entire acetogenin pool measured in the whole mesocarp, while only having 4% of the total fatty acids. The lipidome of this cell type changed the most when the fruit was ripening after harvesting, TAGs decreased while odd-chain DAGs increased. Notably, Idioblast lipidome was more diverse than that from mesocarp. Evidence shown here suggests that Idioblasts are the main site of acetogenin biosynthesis in avocado mesocarp. This work unveiled the prevalence of aliphatic acetogenins in the avocado fruit lipidome and evidenced TAGs as initial donors of the acetogenin backbones in its biosynthesis. It also sets evidence for acetogenins being included in future works aimed at characterizing the avocado seed, as they are a main component of their lipidome.
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Avocado fruit maturation and ripening: dynamics of aliphatic acetogenins and lipidomic profiles from mesocarp, Idioblasts and seed
BMC, 2017Co-Authors: Carlos Eduardo Rodríguez-lópez, Victor Trevino, Carmen Hernández-brenes, Rocio Diaz I De La GarzaAbstract:Abstract Background Avocado fruit contains aliphatic acetogenins (oft-acetylated, odd-chain fatty alcohols) with promising bioactivities for both medical and food industries. However, we have scarce knowledge about their metabolism. The present work aimed to study changes in acetogenin profiles from mesocarp, lipid-containing Idioblasts, and seeds from ‘Hass’ cultivar during fruit development, germination, and three harvesting years. An untargeted LC-MS based lipidomic analysis was also conducted to profile the lipidome of avocado fruit in each tissue. Results The targeted analysis showed that acetogenin profiles and contents remained unchanged in avocado mesocarp during maturation and postharvest ripening, germination, and different harvesting years. However, a shift in the acetogenin profile distribution, accompanied with a sharp increase in concentration, was observed in seed during early maturation. Untargeted lipidomics showed that this shift was accompanied with remodeling of glycerolipids: TAGs and DAGs decreased during fruit growing in seed. Remarkably, the majority of the lipidome in mature seed was composed by acetogenins; we suggest that this tissue is able to synthesize them independently from mesocarp. On the other hand, lipid-containing Idioblasts accumulated almost the entire acetogenin pool measured in the whole mesocarp, while only having 4% of the total fatty acids. The lipidome of this cell type changed the most when the fruit was ripening after harvesting, TAGs decreased while odd-chain DAGs increased. Notably, Idioblast lipidome was more diverse than that from mesocarp. Conclusions Evidence shown here suggests that Idioblasts are the main site of acetogenin biosynthesis in avocado mesocarp. This work unveiled the prevalence of aliphatic acetogenins in the avocado fruit lipidome and evidenced TAGs as initial donors of the acetogenin backbones in its biosynthesis. It also sets evidence for acetogenins being included in future works aimed at characterizing the avocado seed, as they are a main component of their lipidome
John T Trumble - One of the best experts on this subject based on the ideXlab platform.
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secretory avocado Idioblast oil cells evidence of their defensive role against a non adapted insect herbivore
Entomologia Experimentalis Et Applicata, 2000Co-Authors: Cesar Rodriguezsaona, John T TrumbleAbstract:We tested the hypothesis that avocado Idioblast oil cells play a defensive role against herbivorous insects. Toxicities of the intact avocado Idioblast oil cells and the extracted Idioblast oil were compared for three insect herbivores. Spodoptera exigua (Hubner) larvae are generalists that do not feed on avocados. By contrast, Sabulodes aegrotata (Guenee) and Pseudoplusia includens (Walker) larvae are generalist herbivores that readily feed on avocados. All bioassays were performed at a naturally occurring concentration of Idioblast oil cells (2% w/w). Choice experiments showed that S. exigua larvae avoided diet treated with avocado Idioblast oil cells and consume more control than treated diet. In contrast, Idioblast oil cells had no significant antifeedant effects on the adapted S. aegrotata and P. includens larvae. Subsequent experiments designed to assess resistance mechanisms separated pre-ingestive (behavioral) and post-ingestive (physiological) effects of the avocado Idioblast oil cells, and the extracted Idioblast oil, on the two adapted herbivores. Post-ingestive adaptation was the mechanism that allows feeding. Because the impact of the avocado Idioblast oil cells was greatest on the performance of non-adapted S. exigua, additional experiments determined that larvae fed diet containing the oil cells had higher mortality and reduced larval growth compared to controls. Developmental times were significantly prolonged for the survivors. Thus, increased mortality, reduced developmental rates, and antifeedant activity in the non-adapted insect indicate that defense against non-adapted herbivores may be an important function of Idioblast cells in avocados.
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isolation identification and biological activity of isopersin a new compound from avocado Idioblast oil cells
Journal of Natural Products, 1998Co-Authors: Cesar Rodriguezsaona, Jocelyn G. Millar, John T TrumbleAbstract:A new compound, (12Z,15Z)-1-hydroxy-4-oxo-heneicosa-12,15-dien-2-yl acetate, isopersin (2), has been isolated from avocado Idioblast oil cells. In artificial diet bioassays, 2 showed no effects on either larval survivorship or growth of early-instar beet armyworm Spodoptera exigua. In contrast, the isomeric persin (1), (12Z,15Z)-1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene, reduces larval growth at equivalent concentrations (500 μg g-1). Compound 2 is not very stable and isomerizes readily to 1. Both compounds are acid-labile, rearranging rapidly to alkylfuran 3 in the presence of traces of acid.
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Novel Antifeedant and Insecticidal Compounds from Avocado Idioblast Cell Oil
Journal of Chemical Ecology, 1998Co-Authors: Cesar Rodriguez-saona, Jocelyn G. Millar, David F. Maynard, John T TrumbleAbstract:Several insecticidal compounds have been identified by bioassaydriven fractionation of avocado, Persea americana Mill, Idioblast cell oil. A flash chromatography fraction of the oil showed substantial toxicity to early instars of the generalist insect herbivore, Spodoptera exigua (Hübner) (100% mortality after seven days). Following further fractionation, five biologically active compounds, 2-(pentadecyl)furan, 2-(heptadecyl)furan, 2-(1 E -pentadecenyl)furan, 2-(8 Z ,11 Z -heptadecadienyl)furan, and the triglyceride triolein, were identified. Several minor components were also tentatively identified, including 2-(1 Z -pentadecenyl)furan, 2-(1 E -heptadecenyl)furan, and 2-(1 E ,8 Z ,11 Z -heptadecatrienyl)furan. Several 2-alkylfurans of this type have been reported previously from avocado ( Persea spp.) and have received the common name of avocadofurans. The major compounds were tested individually for toxic and growth inhibitory effects. Individually, the compounds had low to moderate toxicity. Of these, 2-(pentadecyl)furan had the greatest effects, with an LC_50 value of 1031 μg/g. At concentrations of 600 μg/g or higher in diets, larval growth was inhibited by >70% compared to controls. The analogous 2-(heptadecyl)furan had an LC_50 value of 1206 μg/g, and also significantly reduced larval growth (>75% versus controls) at concentrations of >600 μg/g. The unsaturated analogs 2-(1 E -pentadecenyl)furan and 2-(8 Z , 11 Z -heptadecadienyl)furan were less toxic. Triolein was only weakly toxic, with an LC_50 value of 10,364 μg/g diet. Larval growth was inhibited only at concentrations of 7000 μg/g or higher. The potential of avocadofurans in insect control is discussed.
Paul A Nakata - One of the best experts on this subject based on the ideXlab platform.
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advances in our understanding of calcium oxalate crystal formation and function in plants
Plant Science, 2003Co-Authors: Paul A NakataAbstract:Abstract Calcium oxalate crystal formation in plants appears to play a central role in a variety of important functions, including tissue calcium regulation, protection from herbivory, and metal detoxification. Evidence is mounting to support ascorbic acid as the primary precursor to oxalate biosynthesis. The ascorbic acid utilized in oxalate biosynthesis is synthesized directly within the calcium oxalate crystal-accumulating cell, called the crystal Idioblast. Several unique features of the crystal Idioblast have been proposed as factors that influence calcium oxalate formation. These features include an abundance of endoplasmic reticulum (ER), acidic proteins, cytoskeletal components, and the intravacuolar matrix. A number of mutants defective in different aspects of calcium oxalate crystal formation have been isolated. Cellular and biochemical characterizations of the various mutants have revealed mutations affecting crystal nucleation, morphology, distribution, and/or amount. Such mutants will be useful tools in continued efforts to decipher the pathways of crystal formation and function in plants.
Makoto T Fujiwara - One of the best experts on this subject based on the ideXlab platform.
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organ level analysis of Idioblast patterning in egeria densa planch leaves
PLOS ONE, 2015Co-Authors: Takuya Hara, Emi Kobayashi, Kohei Ohtsubo, Shogo Kumada, Mikako Kanazawa, Tomoko Abe, Ryuuichi D Itoh, Makoto T FujiwaraAbstract:Leaf tissues of plants usually contain several types of Idioblasts, defined as specialized cells whose shape and contents differ from the surrounding homogeneous cells. The spatial patterning of Idioblasts, particularly of trichomes and guard cells, across the leaf epidermis has received considerable attention as it offers a useful biological model for studying the intercellular regulation of cell fate and patterning. Excretory Idioblasts in the leaves of the aquatic monocotyledonous plant Egeria densa produced light blue autofluorescence when irradiated with ultraviolet light. The use of epifluorescence microscopy to detect this autofluorescence provided a simple and convenient method for detecting excretory Idioblasts and allowed tracking of those cells across the leaf surfaces, enabling quantitative measurement of the clustering and spacing patterns of Idioblasts at the whole leaf level. Occurrence of Idioblasts was coordinated along the proximal–distal, medial–lateral, and adaxial–abaxial axes, producing a recognizable consensus spatial pattern of Idioblast formation among fully expanded leaves. Idioblast clusters, which comprised up to nine cells aligned along the proximal–distal axis, showed no positional bias or regularity in Idioblast-forming areas when compared with singlet Idioblasts. Up to 75% of Idioblasts existed as clusters on every leaf side examined. The Idioblast-forming areas varied between leaves, implying phenotypic plasticity. Furthermore, in young expanding leaves, autofluorescence was occasionally detected in a single giant vesicle or else in one or more small vesicles, which eventually grew to occupy a large portion of the Idioblast volume as a central vacuole. Differentiation of vacuoles by accumulating the fluorescence substance might be an integral part of Idioblast differentiation. Red autofluorescence from chloroplasts was not detected in Idioblasts of young expanding leaves, suggesting Idioblast differentiation involves an arrest in chloroplast development at a very early stage, rather than transdifferentiation of chloroplast-containing epidermal cells.
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Consensus areas of Idioblast formation on E. densa leaves.
2015Co-Authors: Takuya Hara, Emi Kobayashi, Kohei Ohtsubo, Shogo Kumada, Mikako Kanazawa, Tomoko Abe, Ryuuichi D Itoh, Makoto T FujiwaraAbstract:(A, B) The apical (A) and basal (B) leaf zones defined in this study. Double arrowheads represent marginal tooth cells marking the boundaries between the central zone and the apical or basal zone. (C, D) Three schematics of Idioblast cluster distributions on the adaxial (C) or abaxial (D) side of mature leaves. Color-dot annotation as in Fig. 4. (E, F) Schematic representations of areas of maximal (light-colored) and minimal (dense-colored) Idioblast formation on the adaxial (E) and abaxial (F) surfaces of leaves. White areas represent a complete absence of Idioblasts. Scale bars: 500 μm (A, B); 2 mm (C, D).
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Distribution patterns of Idioblast clusters on the adaxial and abaxial surfaces of leaves.
2015Co-Authors: Takuya Hara, Emi Kobayashi, Kohei Ohtsubo, Shogo Kumada, Mikako Kanazawa, Tomoko Abe, Ryuuichi D Itoh, Makoto T FujiwaraAbstract:(A) Fluorescence images of the adaxial and abaxial surfaces of half-leaves under UV excitation. Scale bar: 1 mm. (B) Schematic of the spatial distribution of singlet (gray), doublet (green), triplet (red), and quadruplet and more (orange) Idioblasts across the half-leaves. (C) Frequency of Idioblast clusters on the whole adaxial and abaxial surfaces of leaves. Data collected from 18 leaves for the adaxial (top) or 19 leaves for the abaxial (bottom) surface are shown. (D, E) Frequency of Idioblast clusters on the whole adaxial and abaxial surfaces of leaves. Data from individual leaves for the adaxial (D) and the abaxial (E) surfaces are shown.
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Plant and leaf structures of Egeria densa.
2015Co-Authors: Takuya Hara, Emi Kobayashi, Kohei Ohtsubo, Shogo Kumada, Mikako Kanazawa, Tomoko Abe, Ryuuichi D Itoh, Makoto T FujiwaraAbstract:(A) Plant stature. (B) Three cell types in the mature leaf epidermis. Epidermal cells (arrowheads), Idioblasts (arrows) and a marginal prickle-hair or tooth cell (double arrowhead) are represented. Note that the top surfaces of the projected Idioblasts are in focus in this image. (C) Cross-section of the central zone of the mature leaf. The adaxial and abaxial sides of the leaf and the midrib are indicated. Inset represents magnification of the boxed area and shows an Idioblast (arrow). (D) Bright-field (BF) and ultraviolet (UV)-induced fluorescence images of the leaf epidermis (taken using 10× objective). (E) Fluorescence image of the UV-irradiated leaf epidermis (taken using 4× objective). Scale bars: 5 mm (A); 50 μm (B–D); 200 μm (E).
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Relationship between the leaf surface area and the number of Idioblast clusters or cells.
2015Co-Authors: Takuya Hara, Emi Kobayashi, Kohei Ohtsubo, Shogo Kumada, Mikako Kanazawa, Tomoko Abe, Ryuuichi D Itoh, Makoto T FujiwaraAbstract:(A) Idioblast clusters. (B) Idioblast cells. Data from 18 leaves for the adaxial (open symbols) or 19 leaves for the abaxial (filled symbols) surfaces are plotted.
