The Experts below are selected from a list of 15375 Experts worldwide ranked by ideXlab platform
Praveen K Saxena - One of the best experts on this subject based on the ideXlab platform.
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protoplast to plant regeneration of american elm ulmus americana
Protoplasma, 2015Co-Authors: Andrew Maxwell Phineas Jones, Mukund R. Shukla, G C G Biswas, Praveen K SaxenaAbstract:This study describes a protocol for regeneration of plants from cell suspension-derived protoplasts of American elm (Ulmus americana). Efficient protoplast isolation was achieved from a two-phase culture system through the incorporation of 100 μM 2-aminoindan-2-phosphonic acid, with a yield of approximately 2 × 106 protoplasts/ml packed cell volume. Isolated protoplasts failed to survive in liquid or alginate bead culture systems but initiated and continued to divide when embedded in low melting point agarose beads. Protoplast-derived callus proliferated and differentiated into shoot buds in response to 10 or 20 μM thidiazuron. Differentiated buds elongated and continued to proliferate on elm shoot medium supplemented with 3.0 μM GA3. The protoplast-derived shoots rooted and acclimatized to greenhouse conditions and continued to grow. This system provides the first protoplast-to-plant regeneration system for American elm and provides a framework for the development of protoplast fusion or genome editing technologies.
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inhibition of phenylpropanoid biosynthesis increases cell wall digestibility protoplast isolation and facilitates sustained cell division in american elm ulmus americana
BMC Plant Biology, 2012Co-Authors: Maxwell A P Jones, Abhishek Chattopadhyay, Mukund R. Shukla, Praveen K SaxenaAbstract:Background Protoplast technologies offer unique opportunities for fundamental research and to develop novel germplasm through somatic hybridization, organelle transfer, protoclonal variation, and direct insertion of DNA. Applying protoplast technologies to develop Dutch elm disease resistant American elms (Ulmus americana L.) was proposed over 30 years ago, but has not been achieved. A primary factor restricting protoplast technology to American elm is the resistance of the cell walls to enzymatic degradation and a long lag phase prior to cell wall re-synthesis and cell division.
E N Ashworth - One of the best experts on this subject based on the ideXlab platform.
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response of xylem ray parenchyma cells of red osier dogwood cornus sericea l to freezing stress microscopic evidence of Protoplasm contraction
Plant Physiology, 1994Co-Authors: Z Ristic, E N AshworthAbstract:Freezing behavior of wood tissue of red osier dogwood (Cornus sericea L.) cannot be explained by current concepts of freezing resistance. Previous studies indicated that water in wood tissue presumably froze extracellularly. However, it was observed that xylem ray parenchyma cells within these tissues could survive temperatures as low as -80[deg]C and the walls of these cells did not collapse during freezing (S.R. Malone and E.N. Ashworth [1991] Plant Physiol 95: 871-881). This observation was unexpected and is inconsistent with the current hypothesis of cell response during freezing. Hence, the objective of our study was to further examine the mechanism of freezing resistance of wood tissue of red osier dogwood. We studied freezing stress response of xylem ray parenchyma cells of red osier dogwood using freeze substitution and transmission electron microscopy. Wood samples were collected in winter, spring, and summer of 1992. Specimens were cooled from 0[deg]C to -60[deg]C at 5[deg]C/h. Freezing stress did not affect the structural organization of wood tissue. However, the xylem ray parenchyma cells showed two unique responses to a freezing stress: Protoplasm contraction and Protoplasm fragmentation. Protoplasm contraction was evident at all freezing temperatures and in tissues collected at different times of the year. Cells with fragmented Protoplasm, however, were noticed only in tissues collected in spring and summer. Protoplasm contraction in winter tissue occurred without apparent damage to the Protoplasm. In contrast, Protoplasm contraction in spring and summer tissues was accompanied by substantial damage. No evidence of intracellular ice formation was observed in parenchyma cells exposed to freezing stress. Differences in Protoplasm contraction and appearance of cells with fragmented Protoplasm likely indicated seasonal changes in cold hardiness of the wood tissue of red osier dogwood. We speculate that the appearance of fragmented Protoplasm may indicate that cells are being injured by an alternative mechanism in spring and summer.
Z Ristic - One of the best experts on this subject based on the ideXlab platform.
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response of xylem ray parenchyma cells of red osier dogwood cornus sericea l to freezing stress microscopic evidence of Protoplasm contraction
Plant Physiology, 1994Co-Authors: Z Ristic, E N AshworthAbstract:Freezing behavior of wood tissue of red osier dogwood (Cornus sericea L.) cannot be explained by current concepts of freezing resistance. Previous studies indicated that water in wood tissue presumably froze extracellularly. However, it was observed that xylem ray parenchyma cells within these tissues could survive temperatures as low as -80[deg]C and the walls of these cells did not collapse during freezing (S.R. Malone and E.N. Ashworth [1991] Plant Physiol 95: 871-881). This observation was unexpected and is inconsistent with the current hypothesis of cell response during freezing. Hence, the objective of our study was to further examine the mechanism of freezing resistance of wood tissue of red osier dogwood. We studied freezing stress response of xylem ray parenchyma cells of red osier dogwood using freeze substitution and transmission electron microscopy. Wood samples were collected in winter, spring, and summer of 1992. Specimens were cooled from 0[deg]C to -60[deg]C at 5[deg]C/h. Freezing stress did not affect the structural organization of wood tissue. However, the xylem ray parenchyma cells showed two unique responses to a freezing stress: Protoplasm contraction and Protoplasm fragmentation. Protoplasm contraction was evident at all freezing temperatures and in tissues collected at different times of the year. Cells with fragmented Protoplasm, however, were noticed only in tissues collected in spring and summer. Protoplasm contraction in winter tissue occurred without apparent damage to the Protoplasm. In contrast, Protoplasm contraction in spring and summer tissues was accompanied by substantial damage. No evidence of intracellular ice formation was observed in parenchyma cells exposed to freezing stress. Differences in Protoplasm contraction and appearance of cells with fragmented Protoplasm likely indicated seasonal changes in cold hardiness of the wood tissue of red osier dogwood. We speculate that the appearance of fragmented Protoplasm may indicate that cells are being injured by an alternative mechanism in spring and summer.
Guangce Wang - One of the best experts on this subject based on the ideXlab platform.
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assembly of the Protoplasm of codium fragile bryopsidales chlorophyta into new protoplasts
Journal of Integrative Plant Biology, 2008Co-Authors: Guangce Wang, Baicheng ZhouAbstract:The cell organelles of the coenocytic alga Codium fragile (Sur.) Hariot aggregated rapidly and protoplasts were formed when its Protoplasm was extruded out in seawater. Continuous observation showed that there were long and gelatinous threads connecting the cell organelles. The threads contracted, and thus the cell organelles aggregated into Protoplasmic masses. The enzyme digestion experiments and Coomassie Brilliant Blue and Anthrone stainings showed that the long and gelatinous threads involved in the formation of the protoplasts might include protein and saccharides as structure components. Nile Red staining indicated that the protoplast primary envelope was non-lipid at first, and then lipid materials integrated into its surface gradually. The fluorescent brightener staining indicated that the cell wall did not regenerate in the newly formed protoplasts and they all disintegrated within 72 h after formation. Transmission electron microscopy of the cell wall of wild C. fragile showed electron-dense material embedded in the whole cell wall at regular intervals. The experiments indicated that C. fragile would be a suitable model alga for studying the formation of protoplasts.
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Influence of albumen on aggregation and O2 evolution of Protoplasm from Bryopsis hypnoides Lamourou
Chinese Journal of Oceanology and Limnology, 2008Co-Authors: Guangce WangAbstract:The extruded Protoplasm from the coenocytic green alga, Bryopsis hypnoides Lamouroux, was able to reform a cell wall and develop further into a mature alga in seawater. In this paper, the influence of albumen on the ability of aggregation and on the photosynthesis of Protoplasm was examined. Results show that the Protoplasm of B. hypnoides could aggregate in either albumen or chicken egg, which is similar to that in seawater. However unlike in seawater, the aggregation from B. hypnoides in albumen and chicken egg failed to develop into a mature individual. Interestingly, the Protoplasm of B. hypnoides could maintain its photosynthetic O2 evolution in albumen and chicken egg, while the time in chicken egg was longer than that in albumen.
Mukund R. Shukla - One of the best experts on this subject based on the ideXlab platform.
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protoplast to plant regeneration of american elm ulmus americana
Protoplasma, 2015Co-Authors: Andrew Maxwell Phineas Jones, Mukund R. Shukla, G C G Biswas, Praveen K SaxenaAbstract:This study describes a protocol for regeneration of plants from cell suspension-derived protoplasts of American elm (Ulmus americana). Efficient protoplast isolation was achieved from a two-phase culture system through the incorporation of 100 μM 2-aminoindan-2-phosphonic acid, with a yield of approximately 2 × 106 protoplasts/ml packed cell volume. Isolated protoplasts failed to survive in liquid or alginate bead culture systems but initiated and continued to divide when embedded in low melting point agarose beads. Protoplast-derived callus proliferated and differentiated into shoot buds in response to 10 or 20 μM thidiazuron. Differentiated buds elongated and continued to proliferate on elm shoot medium supplemented with 3.0 μM GA3. The protoplast-derived shoots rooted and acclimatized to greenhouse conditions and continued to grow. This system provides the first protoplast-to-plant regeneration system for American elm and provides a framework for the development of protoplast fusion or genome editing technologies.
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inhibition of phenylpropanoid biosynthesis increases cell wall digestibility protoplast isolation and facilitates sustained cell division in american elm ulmus americana
BMC Plant Biology, 2012Co-Authors: Maxwell A P Jones, Abhishek Chattopadhyay, Mukund R. Shukla, Praveen K SaxenaAbstract:Background Protoplast technologies offer unique opportunities for fundamental research and to develop novel germplasm through somatic hybridization, organelle transfer, protoclonal variation, and direct insertion of DNA. Applying protoplast technologies to develop Dutch elm disease resistant American elms (Ulmus americana L.) was proposed over 30 years ago, but has not been achieved. A primary factor restricting protoplast technology to American elm is the resistance of the cell walls to enzymatic degradation and a long lag phase prior to cell wall re-synthesis and cell division.
