146 research outputs found
Boron Nutrition of Tobacco BY-2 Cells. V. Oxidative Damage is the Major Cause of Cell Death Induced by Boron Deprivation
Boron (B) is an essential micronutrient for vascular plants. However, it remains unclear how B deficiency leads to various metabolic disorders and cell death. To understand this mechanism, we analyzed the physiological changes in suspension-cultured tobacco (Nicotiana tabacum) BY-2 cells upon B deprivation. When 3-day-old cells were transferred to B-free medium, cell death was detectable as early as 12 h after treatment. The B-deprived cells accumulated more reactive oxygen species and lipid peroxides than control cells, and showed a slight but significant decrease in the cellular ascorbate pool. Supplementing the media with lipophilic antioxidants effectively suppressed the death of B-deprived cells, suggesting that the oxidative damage is the immediate and major cause of cell death under B deficiency. Dead cells in B-free culture exhibited a characteristic morphology with a shrunken cytoplasm, which is often seen in cells undergoing programmed cell death (PCD). However, they did not display other hallmarks of PCD such as internucleosomal DNA fragmentation, decreased ascorbate peroxidase expression and protection from death by cycloheximide. These results suggest that the death of tobacco cells induced by B deprivation is not likely to be a typical PCD
Rhamnogalacturonan-II cross-linking of plant pectins via boron bridges occurs during polysaccharide synthesis and/or secretion
Rhamnogalacturonan-II (RG-II), a domain of plant cell wall pectins, is able to cross-link with other RG-II domains through borate diester bridges. Although it is known to affect mechanical properties of the cell wall, the biochemical requirements and lifecycle of this cross-linking remain unclear. We developed a PAGE methodology to allow separation of monomeric and dimeric RG-II and used this to study the dynamics of cross-linking in vitro and in vivo. Rosa cells grown in medium with no added boron contained no RG-II dimers, although these re-appeared after addition of boron to the medium. However, other Rosa cultures which were unable to synthesize new polysaccharides did not show dimer formation. We conclude that RG-II normally becomes cross-linked intraprotoplasmically or during secretion, but not post-secretion
Cardiac magnetic resonance imaging-indeterminate/negative cardiac sarcoidosis revealed by 18F-fluorodeoxyglucose-positron emission tomography: two case reports and a review of the literature
Effects of Boron on Leaf Expansion and Intercellular Airspaces in Mung Bean in Solution Culture
Model of Cation Transportation Mediated by High-Affinity Potassium Transporters (HKTs) in Higher Plants
Salinity tolerance mechanisms in glycophytes: An overview with the central focus on rice plants
Distribuição de nutrientes e sintomas visuais de deficiência de boro em raízes de coqueiro-anão verde
Alterações ligno-anatômicas em Solanum gilo Raddi por aplicação de cálcio e boro como estratégia de defesa
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