The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Christopher M Ford - One of the best experts on this subject based on the ideXlab platform.
-
composition and synthesis of Raphide crystals and druse crystals in berries of vitis vinifera l cv cabernet sauvignon ascorbic acid as precursor for both oxalic and tartaric acids as revealed by radiolabelling studies
Australian Journal of Grape and Wine Research, 2004Co-Authors: Seth Debolt, Jim Hardie, Steve Tyerman, Christopher M FordAbstract:Biomineralisation in the fleshy pericarp of berries of Vitis vinifera L. gives rise to crystals of two distinct forms, viz. Raphides and druses, which are found in exocarp and endocarp cells respectively. Druses have generally been considered as crystalline aggregates of calcium oxalate. However, the organic moiety of Raphide crystals has been commonly accepted as tartrate, although we have found no analytical data to support that assumption. We now present TEM and X-ray powder diffraction analysis data showing that Raphide crystals of V. vinifera berries are composed of calcium oxalate monohydrate. This work also established ascorbic acid as the biosynthetic precursor of both oxalic and tartaric acids. When ascorbic acid labelled with 14C at position 1 was introduced into berries via the rachis, 21% and 52% of the added radiolabel was recovered as oxalic and tartaric acids respectively. Purified crystals from the radiolabelled grape berries contained approximately 20% of the original radioactivity, further confirming the role of ascorbic acid in oxalic acid biosynthesis. To our knowledge, this is the first evidence to be published on the formation of oxalic and tartaric acids from ascorbic acid via two distinct pathways operating within the same physiological entity (organ).
Christina J. Prychid - One of the best experts on this subject based on the ideXlab platform.
-
cellular ultrastructure and crystal development in amorphophallus araceae
Annals of Botany, 2008Co-Authors: Christina J. Prychid, Rachel S Jabaily, Paula J RudallAbstract:† Background and Aims Species of Araceae accumulate calcium oxalate in the form of characteristically grooved needle-shaped Raphide crystals and multi-crystal druses. This study focuses on the distribution and development of Raphides and druses during leaf growth in ten species of Amorphophallus (Araceae) in order to determine the crystal macropatterns and the underlying ultrastructural features associated with formation of the unusual Raphide groove. † Methods Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and both bright-field and polarized-light microscopy were used to study a range of developmental stages. † Key Results Raphide crystals are initiated very early in plant development. They are consistently present in most species and have a fairly uniform distribution within mature tissues. Individual Raphides may be formed by calcium oxalate deposition within individual crystal chambers in the vacuole of an idioblast. Druse crystals form later in the true leaves, and are absent from some species. Distribution of druses within leaves is more variable. Druses initially develop at leaf tips and then increase basipetally as the leaf ages. Druse development may also be initiated in crystal chambers. † Conclusions The unusual grooved Raphides in Amorphophallus species probably result from an unusual crystal chamber morphology. There are multiple systems of transport and biomineralization of calcium into the vacuole of the idioblast. Differences between Raphide and druse idioblasts indicate different levels of cellular regulation. The relatively early development of Raphides provides a defensive function in soft, growing tissues, and restricts build-up of dangerously high levels of calcium in tissues that lack the ability to adequately regulate calcium. The later development of druses could be primarily for calcium sequestration.
-
Calcium Oxalate Crystals in Monocotyledons: A Review of their Structure and Systematics
Annals of Botany, 1999Co-Authors: Christina J. PrychidAbstract:Abstract Three main types of calcium oxalate crystal occur in monocotyledons: Raphides, styloids and druses, although intermediates are sometimes recorded. The presence or absence of the different crystal types may represent ‘useful’ taxonomic characters. For instance, styloids are characteristic of some families of Asparagales, notably Iridaceae, where Raphides are entirely absent. The presence of styloids is therefore a synapomorphy for some families (e.g. Iridaceae) or groups of families (e.g. Philydraceae, Pontederiaceae and Haemodoraceae). This paper reviews and presents new data on the occurrence of these crystal types, with respect to current systematic investigations on the monocotyledons.
Emmanuel Kofiagyir Sackey - One of the best experts on this subject based on the ideXlab platform.
-
starch structure and some properties of cocoyam xanthosoma sagittifolium and colocasia esculenta starch and Raphides
Food Chemistry, 2002Co-Authors: Samuel Sefadedeh, Emmanuel Kofiagyir SackeyAbstract:Abstract Studies were conducted on the structure and rheological properties of three cocoyam varieties [Xanthosoma sagittifolium (red-flesh), Xanthosonia sagittifolium (white-flesh) and colocasia esculenta] starches and Raphides in an attempt to characterize them. The microstructures of starch granules and Raphide sizes, which were obtained from the distal, middle and apical sections of the raw cocoyam samples, were examined using a light microscope. Evaluations of the rheological properties of the cocoyam species were also conducted, using a Brabender viscoamylograph. No distinct variation was observed in starch granule sizes of the two Xanthosoma species. Starch granules sizes in the ranges of 0.74–1.19 and 0.74–1.10 μm were obtained for the Xanthosoma species (red-flesh) and Xanthosoma species (white-flesh), respectively. Significantly smaller sizes (0.05–0.08 μm) of starch granules were observed for Colocasia esculenta. Microstructures of Raphide sizes which were obtained from the distal section of the cocoyam species showed significant differences (P⩽0.05) among the varieties, with the Colocasia species having more pronounced needle-like structures. Evaluation of the rheological properties of the cocoyam flours, using the Brabender viscoamylograph, showed considerable variations among the varieties, especially between the Xanthosoma species and the Colocasia species. The C. esculenta showed lower hot paste viscosity but higher thermal stability than the Xanthosoma species. Peak viscosity was highest in the X. sagittifolium (red-flesh) variety while the white-flesh variety showed the least tendency to retrogradation.
Seth Debolt - One of the best experts on this subject based on the ideXlab platform.
-
composition and synthesis of Raphide crystals and druse crystals in berries of vitis vinifera l cv cabernet sauvignon ascorbic acid as precursor for both oxalic and tartaric acids as revealed by radiolabelling studies
Australian Journal of Grape and Wine Research, 2004Co-Authors: Seth Debolt, Jim Hardie, Steve Tyerman, Christopher M FordAbstract:Biomineralisation in the fleshy pericarp of berries of Vitis vinifera L. gives rise to crystals of two distinct forms, viz. Raphides and druses, which are found in exocarp and endocarp cells respectively. Druses have generally been considered as crystalline aggregates of calcium oxalate. However, the organic moiety of Raphide crystals has been commonly accepted as tartrate, although we have found no analytical data to support that assumption. We now present TEM and X-ray powder diffraction analysis data showing that Raphide crystals of V. vinifera berries are composed of calcium oxalate monohydrate. This work also established ascorbic acid as the biosynthetic precursor of both oxalic and tartaric acids. When ascorbic acid labelled with 14C at position 1 was introduced into berries via the rachis, 21% and 52% of the added radiolabel was recovered as oxalic and tartaric acids respectively. Purified crystals from the radiolabelled grape berries contained approximately 20% of the original radioactivity, further confirming the role of ascorbic acid in oxalic acid biosynthesis. To our knowledge, this is the first evidence to be published on the formation of oxalic and tartaric acids from ascorbic acid via two distinct pathways operating within the same physiological entity (organ).
Ford C. - One of the best experts on this subject based on the ideXlab platform.
-
Composition and synthesis of Raphide crystals and druse crystals in berries of Vitis vinifera L. cv. Cabernet Sauvignon: Ascorbic acid as precursor for both oxalic and tartaric acids as revealed by radiolabelling studies
'Wiley', 2004Co-Authors: Debolt S., Hardie J., Tyerman S., Ford C.Abstract:Copyright © 2008 Australian Society of Viticulture and Oenology Inc.Biomineralisation in the fleshy pericarp of berries of Vitis vinifera L. gives rise to crystals of two distinct forms, viz. Raphides and druses, which are found in exocarp and endocarp cells respectively. Druses have generally been considered as crystalline aggregates of calcium oxalate. However, the organic moiety of Raphide crystals has been commonly accepted as tartrate, although we have found no analytical data to support that assumption. We now present TEM and X-ray powder diffraction analysis data showing that Raphide crystals of V. vinifera berries are composed of calcium oxalate monohydrate. This work also established ascorbic acid as the biosynthetic precursor of both oxalic and tartaric acids. When ascorbic acid labelled with ¹⁴C at position 1 was introduced into berries via the rachis, 21% and 52% of the added radiolabel was recovered as oxalic and tartaric acids respectively. Purified crystals from the radiolabelled grape berries contained approximately 20% of the original radioactivity, further confirming the role of ascorbic acid in oxalic acid biosynthesis. To our knowledge, this is the first evidence to be published on the formation of oxalic and tartaric acids from ascorbic acid via two distinct pathways operating within the same physiological entity (organ).Seth Debolt, Jim Hardie, Steve Tyerman and Christopher M. For