ABSTRACT
Embryos excised from seeds of six generations (P1, P2, F1, BC1, BC2 and F2) of a cross WH 283 WH 533 were cultured on modified MS medium already inoculated with secondary sporidia of Neovossia indica. Significant variations for callusing response (CR) (54 55-75 55%) were observed among generations but the presence or absence of N. indicia did not affect callusing response. A clear inhibition zone (IZ) was formed around each embryo showing callusing. The diameter of IZ varied significantly among generations and was maximum in the resistant genotype, WH 283 (3 60 cm). Fresh weight and dry weight of calli, initiated from embryo cultured and inoculated with N. indica, varied significantly among generations. Coefficient of infection as well as percentage of infection reflected the overdominance of susceptibility. Generation mean analysis showed that the three parameter model was adequate for diameter of IZ only. Six-parameter model showed that additive (in presence of N. indica), additive and additive dominance (in absence of N. indica) effects were also significant. Complementary type of epistasis for fresh weight of calli and dominance, and dominance dominance effects for dry weight of calli were observed in the presence of N. indica. Magnitude of additive effects was higher for diameter of IZ in three parameter model. Therefore, selection might assist in improving this trait and thus indirectly help in attaining the resistance towards N. indica.
Subject(s)
Basidiomycota/physiologyABSTRACT
AK-5 tumour cells undergo apoptosis after treatment with rotenone an electron transport inhibitor and oligomycin which inhibits mitochondrial ATPases. Apoptotic process involves the induction of caspases 2 and 3, whereas caspase 1 does not seem to be participating in rotenone/oligomycin induced apoptosis. DEVD which is a specific inhibitor of caspase 3, inhibited apoptosis in AK-5 cells. We have also observed a significant lowering of intracellular pH in AK-5 cells which are induced into the apoptotic process by rotenone. These results suggest an important role for mitochondrial electron transport in the induction of apoptosis in AK-5 tumour cells.
Subject(s)
Animals , Apoptosis/drug effects , Caspases/metabolism , Rats , Rats, Wistar , Rotenone/pharmacology , Tumor Cells, CulturedABSTRACT
AK-5 tumor cell death is mediated through necrosis and apoptosis. The apoptotic activity in AK-5 cells has been studied after introduction of wild-type p53 gene. Apoptotic activity both in vitro and in vivo is significantly increased in p53 transfected cells. Similarly there is fragmentation of tumor cell DNA after undergoing apoptosis. These observations suggest an active participation of p53 in inducing apoptosis in AK-5 tumor cells.
Subject(s)
Animals , Apoptosis/genetics , Genes, p53 , Histiocytoma, Benign Fibrous/genetics , Rats , Rats, Wistar , TransfectionABSTRACT
The present study was carried out to mechanistically view a possible correlation between the process of, conjugate formation and its relation to target cell death. AK-5 killing is mediated by CD8+ natural killer cells through ADCC. Immune effectors on exposure to antibody primed AK-5 tumor cells formed tight conjugates. Ability of various cell types (NK, T, monocytes and macrophages) to form conjugates was evaluated. Marked increase in the number of NK cells binding to the target as compared to the other cell types was observed. Cytotoxicity of free and bound effectors against antibody tagged AK-5 cells demonstrated a reduced cytotoxic ability of the former in contrast to a significantly high lytic potential of the bound effectors. The results highlight the requirement for priming of NK cells which mediate killing of AK-5 tumor and provide additional evidence that formation of stable conjugates acts as the first signal for triggering lymphocyte activation and effective target cell lysis.
Subject(s)
Animals , Antibodies, Monoclonal/immunology , Antibody-Dependent Cell Cytotoxicity , Cell Death/immunology , Cytotoxicity, Immunologic , Flow Cytometry , Histiocytic Disorders, Malignant/immunology , Killer Cells, Natural/immunology , Rats , Rats, WistarABSTRACT
Tumour necrosis factor (TNF) has been purified from the sera of animals in which the rat histiocytoma AK-5, was rejected spontaneously. Purified TNF-alpha is cytotoxic to AK-5 cells in vitro and the cytotoxic activity of TNF is completely neutralized by anti TNF antiserum. The circulating TNF levels are high by day 10 after the tumour transplantation. Animals which do not regress the tumour have very low levels of TNF in serum. Production of TNF by tumour regressing animals is part of the host immune response to the AK-5 tumour. Also, spleenomegaly in the animals which reject the AK-5 tumour is observed.
Subject(s)
Animals , Cytotoxicity, Immunologic , Graft Rejection/immunology , Histiocytoma, Benign Fibrous/immunology , Mice , Mice, Inbred BALB C , Neoplasm Transplantation , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/isolation & purificationABSTRACT
Status of CD4 and CD8 positive T-lymphocytes, natural killer cells and macrophages has been studied in animals which reject AK-5 histiocytoma. Analysis of immune cells which enter the tumour showed higher number of CD8 positive and NK cells around day 25 after tumour transplantation, suggesting their participation in tumour rejection.
Subject(s)
Animals , Histiocytoma, Benign Fibrous/immunology , Killer Cells, Natural/immunology , Lymphocytes, Tumor-Infiltrating/immunology , Neoplasm Regression, Spontaneous/immunology , Rats , Rats, Wistar , Spleen/immunologyABSTRACT
Properties of a transplantable rat histiocytoma which behaves like a macrophage-like cell, have been described. The AK-5 grows as ascites as well as solid subcutaneous tumor. The ascites from one animal can give between 10(8) and 10(9) cells whereas the subcutaneous tumor grows between 20 and 40 cm3 size. These cells possess various degradative enzymes, macrophage markers and glucocorticoid receptors. Beside histopathology the surface topography and ultrastructure of these cells are described.
Subject(s)
Animals , Cell Division , Female , Histiocytoma, Benign Fibrous/ultrastructure , Macrophages/ultrastructure , Male , Rats , Rats, Inbred Strains , Tumor Cells, Cultured/ultrastructureABSTRACT
Conditions have been standardized to maintain rat vaginal epithelial cells in vitro with more than 95% viability. Cultured epithelial cells were used to study the effects of normal fetal calf scrum, estradiol and progesterone on the incorporation of [3H]-uridine in RNA and incorporation of [l4C]-aminoacids in proteins. While fetal calf serum and estradiol stimulate the incorporation of both uridine and afno acids, progesterone did not show any effect. Estradiol treated vaginal cells show typical fcroridges (indicative of keratinization of cells) in contrast to estradiol deprived cells, which show microvilli on cell surface when examined in scanning electron microscope.