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Patricia I Leonardi - One of the best experts on this subject based on the ideXlab platform.
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mixed evolutionary traits of tolypella section rothia charales compared with chara and Nitella shown by ultrastructure of vegetative internodal cells
Aquatic Botany, 2015Co-Authors: Amelia A Vouilloud, Patricia I Leonardi, Eduardo J CaceresAbstract:Abstract The ultrastructure of vegetative internodal cells in a representative of the genus Tolypella (section Rothia) is described for the first time for Tolypella intricata . The most striking difference compared with the cells of Chara and Nitella is that the four-layered lateral cell wall shows the regular presence of unique refractive lenticular thickenings, which we designate as “tolysomes”, considering their unique ultrastructure elucidated here for the first time. Tolysomes greatly amplify the plasma membrane surface; thereby defining particular spaces of the cytoplasm. There are similar structures in the cell walls of the non-charalean charophyte Coleochaete orbicularis and also in bryophytes, angiosperms and gymnosperms. As the function of tolysomes is hitherto elusive, a bona fide analysis of evolutionary significance is not yet possible. C-shaped amitotic nuclei are similar to those described for young internodal Chara cells. Resting amitotic nuclei exhibit normal nuclear envelope, dispersed granular chromatin and numerous nucleoli with variable size. Nevertheless, they show neither the single, central nucleolus characteristic of dividing Chara nuclei nor the bundles of tubular elements running parallel to the long axis of the nucleus, which are also normal in Chara and Nitella amitotic nuclei . The presence of C-shaped resting nuclei of Tolypella and Chara and their absence in Nitella and the presence of spindle-shaped nuclei in Nitella , but not in Tolypella , suggest that Tolypella (section Rothia) divergence took place earlier than did Nitella in accordance with, but also in contradiction to molecular data. Mature echinoid bodies and chloroplasts in Tolypella intricata are entirely similar to those previously described for Chara and Nitella .
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ultrastructure of mature male gametes of Nitella hyalina charales charophyta
Phycologia, 2010Co-Authors: Amelia A Vouilloud, Patricia I Leonardi, Eduardo J CaceresAbstract:Abstract Vouilloud A.A., Caceres E.J. and Leonardi P.I. 2010. Ultrastructure of mature male gametes of Nitella hyalina (Charales, Charophyta). Phycologia 49: 508–511. DOI: 10.2216/09-111.1 This article describes the ultrastructure of male gametes of Nitella hyalina. Microtubular roots did not surround mitochondria completely. The number of microtubules varied from 12 to19 at the level of mitochondria, from 24 to 31 at the level of the nucleus and from 10 to 21 at different levels of the plastids. The three-membered root is clearly discernible only up to the level of mitochondria. At the rearmost level of the gamete, microtubules were separated in bunches of two to six microtubules each. Mature gametes of N. hyalina were compared with those of other species of Chara and Nitella. This comparative analysis suggests that certain male gamete ultrastructure traits are regularly dissimilar at genus level.
F Liners - One of the best experts on this subject based on the ideXlab platform.
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Changes in distribution of short pectic polysaccharides induced by monovalent ions in the Nitella cell wall
Can. J. Bot., 1996Co-Authors: Christian Gillet, F LinersAbstract:Nitella cell walls exhibit a major loss of pectin when the adsorbed bivalent ions are exchanged for monovalents. 2F4 monoclonal antibody, which recognizes a conformational epitope of homogalacturonic acid induced by calcium ions, was complexed to colloidal gold and used to localize, by means of the electron microscope, the wall regions from which the leakage occurred. Comparison of the labeling between nonpretreated cell walls and NaCl or LiCl pretreated ones, with or without incubation in CDTA or in NaOH, reveals that monovalent ions induce the solubilization of a pectic fraction rich in nonesterified galacturonic acids from the primary wall. Our results also indicate that in the secondary wall of Nitella, the pectic polysaccharides could be closely joined by covalent crosslinking.
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changes in distribution of short pectic polysaccharides induced by monovalent ions in the Nitella cell wall
Botany, 1996Co-Authors: Christian Gillet, F LinersAbstract:Nitella cell walls exhibit a major loss of pectin when the adsorbed bivalent ions are exchanged for monovalents. 2F4 monoclonal antibody, which recognizes a conformational epitope of homogalacturonic acid induced by calcium ions, was complexed to colloidal gold and used to localize, by means of the electron microscope, the wall regions from which the leakage occurred. Comparison of the labelling between nonpretreated cell walls and NaCl or LiCl pretreated ones, with or without incubation in CDTA or in NaOH, reveals that monovalent ions induce the solubilization of a pectic fraction rich in nonesterified galacturonic acids from the primary wall. Our results also indicate that in the secondary wall of Nitella, the pectic polysaccharides could be closely joined by covalent crosslinking. RCsumC : Les parois cellulaires de Nitella perdent une quantitC importante de pectine lorsque les ions bivalents, qui y sont adsorb& sont remplaces par des monovalents. Nous avons utilisC en immunocytochimie des parois isolCes, l'anticorps monoclonal 2F4 qui reconnait un Cpitope conformationnel induit par les ions calcium, pour localiser les regions ti partir desquelles se produit la perte de pectine. La comparaison entre le marquage des parois cellulaires prCtraitCes ou non par des solutions de NaCl ou de LiC1, avec ou sans incubation dans CDTA ou dans NaOH, montre que les ions monovalents induisent la solubilisation B partir de la paroi primaire d'une fraction pectique riche en acide galacturonique non-estCrifiC. Nos rCsultats montrent aussi que les polysaccharides pectiques seraient surtout unis par liaisons covalentes dans la paroi secondaire de Nitella. Mots clis : pectine, marquage d'or, anticorps monoclonal, Cchange ionique, Nitella.
Masashi Tazawa - One of the best experts on this subject based on the ideXlab platform.
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in vitro demonstration of hydration induced calcium release in cells of Nitella flexilis
Proceedings of the Japan Academy. Ser. B: Physical and Biological Sciences, 1995Co-Authors: Munehiro Kikuyama, Kiyo Shimada, Kaoru Katoh, Masashi TazawaAbstract:When cells of Nitella flexilis are subjected to transcellular osmosis or osmotic swelling, cytosolic free Ca2+ ([Ca2+]c) increases. Ca2+ is thought to be released from internal stores due to hydration of the cytoplasm. In the present study we demonstrated that the hydration-induced Ca2+ release (HICR) can occur in isolated cytoplasm whether or not it contains chloroplasts.
Ashley Garrill - One of the best experts on this subject based on the ideXlab platform.
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the synthesis of nppb and npbb by reductive amination and the effects of these compounds on k channels of the alga Nitella hookeri
Bioorganic & Medicinal Chemistry Letters, 2003Co-Authors: Kristian R Giles, Mark Humphries, Andrew D Abell, Ashley GarrillAbstract:Abstract This paper communicates a new synthesis of the ion channel inhibitors NPPB and NPBB using a simple reductive amination sequence. The synthesised compounds were found to reduce channel amplitude of a K + channel present in cytoplasmic droplets of Nitella hookeri .
Christian Gillet - One of the best experts on this subject based on the ideXlab platform.
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Changes in distribution of short pectic polysaccharides induced by monovalent ions in the Nitella cell wall
Can. J. Bot., 1996Co-Authors: Christian Gillet, F LinersAbstract:Nitella cell walls exhibit a major loss of pectin when the adsorbed bivalent ions are exchanged for monovalents. 2F4 monoclonal antibody, which recognizes a conformational epitope of homogalacturonic acid induced by calcium ions, was complexed to colloidal gold and used to localize, by means of the electron microscope, the wall regions from which the leakage occurred. Comparison of the labeling between nonpretreated cell walls and NaCl or LiCl pretreated ones, with or without incubation in CDTA or in NaOH, reveals that monovalent ions induce the solubilization of a pectic fraction rich in nonesterified galacturonic acids from the primary wall. Our results also indicate that in the secondary wall of Nitella, the pectic polysaccharides could be closely joined by covalent crosslinking.
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changes in distribution of short pectic polysaccharides induced by monovalent ions in the Nitella cell wall
Botany, 1996Co-Authors: Christian Gillet, F LinersAbstract:Nitella cell walls exhibit a major loss of pectin when the adsorbed bivalent ions are exchanged for monovalents. 2F4 monoclonal antibody, which recognizes a conformational epitope of homogalacturonic acid induced by calcium ions, was complexed to colloidal gold and used to localize, by means of the electron microscope, the wall regions from which the leakage occurred. Comparison of the labelling between nonpretreated cell walls and NaCl or LiCl pretreated ones, with or without incubation in CDTA or in NaOH, reveals that monovalent ions induce the solubilization of a pectic fraction rich in nonesterified galacturonic acids from the primary wall. Our results also indicate that in the secondary wall of Nitella, the pectic polysaccharides could be closely joined by covalent crosslinking. RCsumC : Les parois cellulaires de Nitella perdent une quantitC importante de pectine lorsque les ions bivalents, qui y sont adsorb& sont remplaces par des monovalents. Nous avons utilisC en immunocytochimie des parois isolCes, l'anticorps monoclonal 2F4 qui reconnait un Cpitope conformationnel induit par les ions calcium, pour localiser les regions ti partir desquelles se produit la perte de pectine. La comparaison entre le marquage des parois cellulaires prCtraitCes ou non par des solutions de NaCl ou de LiC1, avec ou sans incubation dans CDTA ou dans NaOH, montre que les ions monovalents induisent la solubilisation B partir de la paroi primaire d'une fraction pectique riche en acide galacturonique non-estCrifiC. Nos rCsultats montrent aussi que les polysaccharides pectiques seraient surtout unis par liaisons covalentes dans la paroi secondaire de Nitella. Mots clis : pectine, marquage d'or, anticorps monoclonal, Cchange ionique, Nitella.