Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Wild-type (WT) plants of potato (Solanum tuberosum L.) and their transgenic forms carrying agrobacterial genes rolB or rolC under the control of B33 class I patatin promoter were cultured in vitro on MS medium with 2% sucrose in a controlled-climate chamber at 16-h illumination and 22A degrees C. These plants were used as a source of single-node stem cuttings, which were cultured in darkness on the same medium supplemented with 8% sucrose. The tubers formed on them were used for determination of the structure of native starch using the methods of differential scanning microcalorimetry (DSC), X-ray scattering, and scanning electron microscopy. It was found that, in starch from the tubers of rolB-plants, the temperature of crystalline lamella melting was lower and their thickness was less than in WT potato. In tubers of rolC plants, starch differed from starch in WT plants by a higher melting temperature, considerably reduced melting enthalpy, and a greater thickness of crystalline lamellae. Deconvolution of DSC thermogram makes it possible to interpret the melting of starch from the tubers of rolC plants as the melting of two independent crystalline structures with melting temperatures of 65.0 and 69.8A degrees C. Electron microscopic examination confirmed the earlier obtained data indicating that, in the tubers of rolC plants, starch granules are smaller and in the tubers of rolB plants larger than in WT plants. Possible ways of influence of rol transgenes on structural properties of starch in amyloplasts of potato tubers are discusse

Effects of Agrobacterial rol-Genes on the Thermodynamic and Structural Features of Starches Extracted from Potato Microtubers

Wild-type potato (Solanum tuberosum L.) plants and their transformants harboring agrobacterial rolB or rolC genes under control of the patatin class I promoter were cultured in vitro. These plants were used as a source of single-node stem cuttings. The structure of native starch in tubers formed on cuttings was determined using methods of X-ray scattering and differential scanning microcalorimetry (DSC). It was found that in starch from tubers of rolB plants the melting temperature of crystalline lamella was lower and their thickness was less than that in wild-type potato. In tubers of rolC plants starch differed from starch in wild-type plants by a higher melting temperature, reduced melting enthalpy, and a greater thickness of crystalline lamellae. The melting of starch from tubers of rolC plants proceeded as the melting of two independent crystalline structures with melting temperatures of 338.0°K and 342.8°K. Overall data show that starches of different structure can be obtained by using transgenic approac

Hormonal Regulation of Tuber Formation in Potato

Tubers of potato (Solanum tuberosum L.) plants serve as organs for vegetative propagation and stock of matter and energy for the next generation. Tuber formation is a complex process involving several successive stages: stolon formation and growth, induction of tuberization, tuber initiation and further growth. Tuber formation is affected by several external and internal factors, fi rst of all photoperiod, temperature, levels of carbohydrates and nitrogen. Adaptive response of tuberization to these cues is a part of the seasonal strategy of potato reproductive development

Regulation of potato tuber dormancy and sprouting

Dormancy is the final stage of tuber life serving to preserve tubers as organs of vegetative reproduction under unfavorable growth conditions. Since the duration of potato tuber dormancy and their sprouting time have significant economic importance, much attention is given to the study of the regulation of these processes. This review considers metabolite, genetic, and hormonal aspects of regulation of potato (Solanum tuberosum L.) tuber dormancy and sprouting. Particular attention is paid to the relationship between processes occurring in different parts of the tuber: its storage tissues and buds. The interaction of hormonal and metabolite (carbohydrate) regulation of dormancy and sprouting is discussed

Discussing the problem of age-related cataract pathogenesis in human: Morphological and immunohistochemical aspects

This chapter is focusing on the one of contemporary medical biology fundamentalproblems - the problem of tissue differentiation in living organisms stability supportingfactors. The data of immunohistochemical investigations show the significant differences inthe lens cells phenotype in norm and after the various type of age-related cataractdevelopment in human. This investigation revealed that the changes in the lens cellsphenotype depended on the age-related cataract type. It was proven that the lens cellsimmunohistochemical status differences determined the different pathogenesismechanisms of age-related dystrophic processes in the human crystalline lens. The purpose of the publication is to attract the researchers' attention to a necessity ofthe differentiated approach elaboration to the preventive and therapeutic ways intreatment of the age-related human cataract depended on the specific type. Conclusions: This investigation discovered the significant differences inmorphological and immunohistochemical status of lens cells in age-related cortical andnuclear cataract forming. This demonstrates the necessity of the differentiated viewformation to study the pathogenesis of age-related cataract in human depended on itstype. Audience: histologists, physiologists, ophthalmologists, gerontologists, postgraduatestudents and students of medical institutes. © 2010 Nova Science Publishers, Inc. All rights reserved

Discussing the problem of age-related cataract pathogenesis in human: Morphological and immunohistochemical aspects

This chapter is focusing on the one of contemporary medical biology fundamentalproblems - the problem of tissue differentiation in living organisms stability supportingfactors. The data of immunohistochemical investigations show the significant differences inthe lens cells phenotype in norm and after the various type of age-related cataractdevelopment in human. This investigation revealed that the changes in the lens cellsphenotype depended on the age-related cataract type. It was proven that the lens cellsimmunohistochemical status differences determined the different pathogenesismechanisms of age-related dystrophic processes in the human crystalline lens. The purpose of the publication is to attract the researchers' attention to a necessity ofthe differentiated approach elaboration to the preventive and therapeutic ways intreatment of the age-related human cataract depended on the specific type. Conclusions: This investigation discovered the significant differences inmorphological and immunohistochemical status of lens cells in age-related cortical andnuclear cataract forming. This demonstrates the necessity of the differentiated viewformation to study the pathogenesis of age-related cataract in human depended on itstype. Audience: histologists, physiologists, ophthalmologists, gerontologists, postgraduatestudents and students of medical institutes. © 2010 Nova Science Publishers, Inc. All rights reserved

Thermodynamic and structural properties of tuber starches from transgenic potato plants grown in vitro and in vivo

Potato plants harboring Phytochrome B (PHYB) gene from Arabidopsis thaliana or rol genes from Agrobacterium rhizogenes were used to study the effect of transgene expression on structure and properties of starch in tubers. Thermodynamic characteristics of starch (melting temperature, enthalpy of melting, thickness of crystalline lamellae) were shown to be variable depending on the transgene expression and plant culturing mode: in vitro or in soil. The expression of rolB or rolC genes in in vitro cultured plants evoked opposite effects on starch melting temperature and crystalline lamellae thickness. AtPHYB or rolB expression in the soil-grown potato led to the formation of more defective or more ordered starch structures, respectively, in comparison with starches of the same lines grown in vitro. On the whole, our study revealed genotype-dependent differences between starches extracted from tubers of in vitro or in vivo grown plants