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Transgenic sweetpotato ( Ipomoea batatas L. cv. Yulmi) plants expressing the Arabidopsis nucleoside diphosphate kinase 2 ( AtNDPK2) gene under the control of an oxidative stress–inducible peroxidase ( SWPA2) promoter (referred to as SN plants) were developed and evaluated for enhanced tolerance of SN plants under various abiotic stress conditions. The level of AtNDPK2 expression and NDPK activity in SN plants following methyl viologen (MV) treatment was positively correlated with the plant’s tolerance to MV. Interestingly, we observed that antioxidant enzyme activities such as peroxidase, ascorbate peroxidase, and catalase increased in MV-treated SN plants. In addition, SN plants showed enhanced tolerance to cold, high salinity, and drought stresses by an increase in the activity of H2O2 scavenging enzymes. These results indicate that overexpression of AtNDPK2 in sweetpotato might efficiently modulate oxidative stress from various environmental stresses. [ABSTRACT FROM AUTHOR]

Calcineurin (Cn) is a calcium/calmodulin-dependent serine/threonine protein phosphatase that has diverse functions in different cell types and organisms. We screened proteins interacting with the C. elegans CnA homolog, TAX-6, by the yeast two-hybrid system. CNP-3 (Calcineurin interacting protein-3) is a novel protein that physically interacts with the catalytic domain of TAX-6. It is strongly expressed in the nuclei of intestine, hypodermis, dorsal uterine regions and spermatheca. Expression begins around the 60-cell stage and proceeds during all larval stages and the adult. To elucidate the biological function of cnp-3 we isolated a cnp-3 deletion mutant. Since CNP-3 binds CnA, we looked at factors associated with calcineurin loss-of-function mutants, such as brood size, body size, serotonin- and levamisole-mediated egg-laying behavior. The cnp-3(jh145) single mutant had no gross defects compared to wild-type animal. However, the phenotypes of the double mutants, tax-6(p675);cnp- 3(jh145) and cnb-1(jh103);cnp-3(jh145), were more severe in terms of brood size, body size and serotoninmediated egg-laying defects than tax-6(p675) and cnb- 1(jh103), respectively. These results suggest that dysfunction of cnp-3 enhances certain calcineurin loss-offunction phenotypes in C. elegans. [ABSTRACT FROM AUTHOR]

Oxidative stress is one of the major factors causing injury to plants exposed to environmental stress. Transgenic sweetpotato [ Ipomoea batatas (L.) Lam. cv. Yulmi] plants with an enhanced tolerance to multiple environmental stresses were developed by expressing the genes of both CuZn superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) under the control of an oxidative stress-inducible SWPA2 promoter in the chloroplasts of sweetpotato plants (referred to as SSA plants). SSA plants were successfully generated by the particle bombardment method and confirmed by PCR analysis. When leaf discs of SSA plants were subjected to 5 μ M methyl viologen (MV), they showed approximately 45% less damage than non-transformed (NT) plants. When 200 μ M MV was sprayed onto the whole plants, SSA plants showed a significant reduction in visible damage compared to leaves of NT plants, which were almost destroyed. The expression of the introduced CuZnSOD and APX genes in leaves of SSA plants following MV treatment was significantly induced, thereby reflecting increased levels of SOD and APX in the chloroplasts. APX activity in chloroplast fractions isolated from SSA plants was approximately 15-fold higher than that in their counterparts from NT plants. SSA plants treated with a chilling stress consisting of 4°C for 24 h exhibited an attenuated decrease in photosynthetic activity (Fv/Fm) relative to NT plants; furthermore, after 12 h of recovery following chilling, the Fv/Fm of SSA plants almost fully recovered to the initial levels, whereas NT plants remained at a lower level of Fv/Fm activity. These results suggest that SSA plants would be a useful plant crop for commercial cultivation under unfavorable growth conditions. In addition, the manipulation of the antioxidative mechanism in chloroplasts can be applied to the development of various other transgenic crops with an increased tolerance to multiple environmental stresses. [ABSTRACT FROM AUTHOR]

Presents a study on the resistance of mitochondrial DNA-deficient cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Role of mitochondrial function in TRAIL-induced apoptosis; Morphological changes of mitochondria after TRAIL treatment; Effect of mitochondrial DNA depletion on cytochrome c translocation.

Describes the purification and characterization of thermostable chaperonin of the thermosome family from hyperthermophilic archaeon Thermococcus profunds. Structure of Thermococcus thermosome; Correlation averages of thermosome oligomer; Conformation of different nucleotide-bound states of the thermosome.