The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Jason T.c. Tzen - One of the best experts on this subject based on the ideXlab platform.
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A new method for seed oil body purification and examination of oil body integrity following germination.
Journal of biochemistry, 1997Co-Authors: Jason T.c. Tzen, Chichung Peng, Dor-jih Cheng, Emily C.f. Chen, Joyce M.h. ChiuAbstract:Plant seeds store triacylglycerols as energy sources for germination and postgerminative growth of seedlings. The triacylglycerols are preserved in small, discrete, intracellular organelles called oil bodies. A new method was developed to purify seed oil bodies. The method included extraction, flotation by centrifugation, detergent washing, ionic elution, treatment with a chaotropic agent, and integrity testing by use of hexane. These processes subsequently removed non-specifically associated or trapped proteins within the oil bodies. Oil bodies purified by this method maintained their integrity and displayed electrostatic repulsion and steric hindrance on their surface. Compared with the previous procedure, this method allowed higher purification of oil bodies, as demonstrated by SDS-PAGE using five species of oilseeds. Oil bodies purified from sesame were further analyzed by two-dimensional gel electrophoresis and revealed two potential oleosin isoforms. The integrity of oil bodies in germinating sesame seedlings was examined by hexane extraction. Our results indicated that consumption of triacylglycerols reduced gradually the total amount of oil bodies in seedlings, whereas no alteration was observed in the integrity of remaining oil bodies. This observation implies that oil bodies in germinating seeds are not degraded simultaneously. It is suggested that glyoxisomes, with the assistance of mitochondria, fuse and digest oil bodies one at a time, while the remaining oil bodies are preserved intact during the whole period of germination.
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Characterization of Seed Oil Bodies and Their Surface Oleosin Isoforms from Rice Embryos
Journal of biochemistry, 1996Co-Authors: Rachel L.c. Chuang, Jeff C.f. Chen, Jessie Chu, Jason T.c. TzenAbstract:Plant seeds store triacylglycerols in discrete organelles called oil bodies. An oil body stores a matrix of triacylglycerols surrounded by phospholipids and alkaline proteins termed oleosins. Oil bodies in rice seeds are present in embryos and aleurone layers. They do not coalesce in crowded environments, as observed on electron microscopy. The detected isoelectric point of purified rice oil bodies is pH 6.2. This implies that rice oil bodies possess a negatively charged surface at neutral pH. The suspension of rice oil bodies in pH 6.5 buffer induces aggregation. Presumably, the negatively charged surface causes electrostatic repulsion that maintains rice oil bodies as discrete organelles. Rice oil bodies lose their integrity on trypsin treatment. Undoubtedly, oleosins play an important role in the stability of oil bodies. There are two oleosin isoforms in rice oil bodies. Antibodies raised against these two homologous isoforms do not cross-recognize each other. Both isoforms are restricted to oil bodies, as detected on immuno-assaying. Partial amino acid sequences of these two isoforms were obtained, and compared with the deduced sequences of two maize and two rice oleosin genes. The comparison confirmed that the two major proteins in rice oil bodies are the two oleosin isoforms.
Lourdes Agapito - One of the best experts on this subject based on the ideXlab platform.
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automated articulated structure and 3d shape recovery from point correspondences
International Conference on Computer Vision, 2011Co-Authors: Joao Fayad, Chris Russell, Lourdes AgapitoAbstract:In this paper we propose a new method for the simultaneous segmentation and 3D reconstruction of interest point based articulated motion. We decompose a set of point tracks into rigid-bodied overlapping regions which are associated with skeletal links, while joint centres can be derived from the regions of overlap. This allows us to formulate the problem of 3D reconstruction as one of model assignment, where each model corresponds to the motion and shape parameters of an articulated body part. We show how this labelling can be optimised using a combination of pre-existing graph-cut based inference, and robust structure from motion factorization techniques. The strength of our approach comes from viewing both the decomposition into parts, and the 3D reconstruction as the optimisation of a single cost function, namely the image re-projection error. We show results of full 3D shape recovery on challenging real-world sequences with one or more articulated bodies, in the presence of outliers and missing data.
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ICCV - Automated articulated structure and 3D shape recovery from point correspondences
2011 International Conference on Computer Vision, 2011Co-Authors: Joao Fayad, Chris Russell, Lourdes AgapitoAbstract:In this paper we propose a new method for the simultaneous segmentation and 3D reconstruction of interest point based articulated motion. We decompose a set of point tracks into rigid-bodied overlapping regions which are associated with skeletal links, while joint centres can be derived from the regions of overlap. This allows us to formulate the problem of 3D reconstruction as one of model assignment, where each model corresponds to the motion and shape parameters of an articulated body part. We show how this labelling can be optimised using a combination of pre-existing graph-cut based inference, and robust structure from motion factorization techniques. The strength of our approach comes from viewing both the decomposition into parts, and the 3D reconstruction as the optimisation of a single cost function, namely the image re-projection error. We show results of full 3D shape recovery on challenging real-world sequences with one or more articulated bodies, in the presence of outliers and missing data.
Gen Morinaga - One of the best experts on this subject based on the ideXlab platform.
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the convergent evolution of snake like forms by divergent evolutionary pathways in squamate reptiles
Evolution, 2019Co-Authors: Philip J Bergmann, Gen MorinagaAbstract:Convergent evolution of phenotypes is considered evidence that evolution is deterministic. Establishing if such convergent phenotypes arose through convergent evolutionary pathways is a stronger test of determinism. We studied the evolution of snake-like body shapes in six clades of lizards, each containing species ranging from short-bodied and pentadactyl to long-bodied and limbless. We tested whether body shapes that evolved in each clade were convergent, and whether clades evolved snake-like body shapes following convergent evolutionary pathways. Our analyses showed that indeed species with the same numbers of digits in each clade evolved convergent body shapes. We then compared evolutionary pathways among clades by considering patterns of evolutionary integration and shape of relationship among body parts, patterns of vertebral evolution, and models of digit evolution. We found that all clades elongated their bodies through the addition, not elongation, of vertebrae, and had similar patterns of integration. However, patterns of integration, the body parts that were related by a linear or a threshold model, and patterns of digit evolution differed among clades. These results showed that clades followed different evolutionary pathways. This suggests an important role of historical contingency as opposed to determinism in the convergent evolution of snake-like body shapes.
Joyce M.h. Chiu - One of the best experts on this subject based on the ideXlab platform.
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A new method for seed oil body purification and examination of oil body integrity following germination.
Journal of biochemistry, 1997Co-Authors: Jason T.c. Tzen, Chichung Peng, Dor-jih Cheng, Emily C.f. Chen, Joyce M.h. ChiuAbstract:Plant seeds store triacylglycerols as energy sources for germination and postgerminative growth of seedlings. The triacylglycerols are preserved in small, discrete, intracellular organelles called oil bodies. A new method was developed to purify seed oil bodies. The method included extraction, flotation by centrifugation, detergent washing, ionic elution, treatment with a chaotropic agent, and integrity testing by use of hexane. These processes subsequently removed non-specifically associated or trapped proteins within the oil bodies. Oil bodies purified by this method maintained their integrity and displayed electrostatic repulsion and steric hindrance on their surface. Compared with the previous procedure, this method allowed higher purification of oil bodies, as demonstrated by SDS-PAGE using five species of oilseeds. Oil bodies purified from sesame were further analyzed by two-dimensional gel electrophoresis and revealed two potential oleosin isoforms. The integrity of oil bodies in germinating sesame seedlings was examined by hexane extraction. Our results indicated that consumption of triacylglycerols reduced gradually the total amount of oil bodies in seedlings, whereas no alteration was observed in the integrity of remaining oil bodies. This observation implies that oil bodies in germinating seeds are not degraded simultaneously. It is suggested that glyoxisomes, with the assistance of mitochondria, fuse and digest oil bodies one at a time, while the remaining oil bodies are preserved intact during the whole period of germination.
Joao Fayad - One of the best experts on this subject based on the ideXlab platform.
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automated articulated structure and 3d shape recovery from point correspondences
International Conference on Computer Vision, 2011Co-Authors: Joao Fayad, Chris Russell, Lourdes AgapitoAbstract:In this paper we propose a new method for the simultaneous segmentation and 3D reconstruction of interest point based articulated motion. We decompose a set of point tracks into rigid-bodied overlapping regions which are associated with skeletal links, while joint centres can be derived from the regions of overlap. This allows us to formulate the problem of 3D reconstruction as one of model assignment, where each model corresponds to the motion and shape parameters of an articulated body part. We show how this labelling can be optimised using a combination of pre-existing graph-cut based inference, and robust structure from motion factorization techniques. The strength of our approach comes from viewing both the decomposition into parts, and the 3D reconstruction as the optimisation of a single cost function, namely the image re-projection error. We show results of full 3D shape recovery on challenging real-world sequences with one or more articulated bodies, in the presence of outliers and missing data.
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ICCV - Automated articulated structure and 3D shape recovery from point correspondences
2011 International Conference on Computer Vision, 2011Co-Authors: Joao Fayad, Chris Russell, Lourdes AgapitoAbstract:In this paper we propose a new method for the simultaneous segmentation and 3D reconstruction of interest point based articulated motion. We decompose a set of point tracks into rigid-bodied overlapping regions which are associated with skeletal links, while joint centres can be derived from the regions of overlap. This allows us to formulate the problem of 3D reconstruction as one of model assignment, where each model corresponds to the motion and shape parameters of an articulated body part. We show how this labelling can be optimised using a combination of pre-existing graph-cut based inference, and robust structure from motion factorization techniques. The strength of our approach comes from viewing both the decomposition into parts, and the 3D reconstruction as the optimisation of a single cost function, namely the image re-projection error. We show results of full 3D shape recovery on challenging real-world sequences with one or more articulated bodies, in the presence of outliers and missing data.
