Fast recovery of transgenic submergence tolerant rice cultivars of North-East India by early co-cultivation of Agrobacterium with pre-cultured callus

Agro-climatic conditions of North-East India are very complex and rice cultivars present in the region have been adapted to grow under harsh environmental conditions. Germplasm present in the region is considered to possess several important and unique traits that are of importance in rice improvement programs. Genetic engineering is a powerful tool to introduce new traits into crop plants. However, not much information is available on the methods to introduce foreign genes into North-East rice cultivars. Therefore, the main objective of this study is to develop transformation procedures for fast recovery of transgenic plants from North-East rice cultivars. To achieve this objective, a systematic study was carried out to identify media components and culture conditions for efficient embryogenic callus induction from the mature seeds and differentiation of callus into plantlets from two North-East deep water rice cultivars, Taothabi and Khongan. Also, role of preculture of callus on Agrobacterium-mediated transformation was studied. Co-cultivation of Agrobacterium with 1-5 days precultured callus was found to result in high frequency of transformation. Detailed characterization of transgenic lines confirmed stable integration of transgenes and expression of reporter gfp gene. The whole process starting from callus induction to regenerating of transgenic rice plants that can be established in the soil was achieved in about 35-45 days. The procedures developed were found to be applicable to a popular variety IR 64. Therefore, methods developed in this study should be useful not only to introduce new traits quickly but also to validate the function(s) of several candidate gene(s) identified under the functional genomics of rice.

Free radicals antioxidant enzymes and lipid peroxidation in different types of leukemias

Free radicals are highly reactive species that have been implicated in the pathogenesis of many diseases. Reactive oxygen species can initiate lipid peroxidation and DNA damage leading to mutagenesis, carcinogenesis and cell death, if the antioxidant system is impaired. This study was undertaken to examine the prevalence of oxidative stress and the role of antioxidant defence in untreated leukemia patients. The generation of superoxide anion and hydrogen peroxide by leukocytes, plasma malondialdehyde levels, red cell copper zinc superoxide dismutase (Cu-Zn SOD) and glutathione peroxidase (GSH-PX) activities were determined in 30 patients with different types of leukemias prior to therapy. The superoxide anion generation by polymorphonuclear leukocytes was found to be significantly increased in leukemia patients especially those with acute lymphocytic and nonlymphocytic leukemias, while the hydrogen peroxide levels were comparable to the control values. Plasma lipid peroxidation products in untreated leukemia patients were in the normal range. Red cell Cu-Zn SOD and GSH-PX activities were significantly increased and showed no correlation with the hemoglobin content. Although superoxide generation was high, lipid peroxide levels were normal in these patients. This might be due to the increased activities of the antioxidant enzymes (SOD, GSH-PX) which counteract lipid peroxidation. Increased free radical generation, especially superoxide anion in leukemia patients and increased antioxidant defence enzymes, which is an adaptive protective response, are indicative of mild oxidative stress. There were no significant differences for the parameters cited above between different types of leukemias, suggesting that the changes are not specific to the type of leukemia.

Leukocyte glucose 6 phosphate dehydrogenase as prognostic indicator in ANLL and CML

Glucose 6 phosphate dehydrogenase (G6PD) was estimated in the leucocytes of 35 patients with acute non-lymphocytic leukemia (ANLL) and 10 patients with chronic myeloid leukemia (CML). G6PD levels were found to be significantly decreased in majority of the patients with ANLL while it was increased in all CML patients. Variation in G6PD was found to be dependent on the percentage of myelocytes inANLL. Cytogenetic analysis was also carried out in these patients. Correlation analysis of leucocyte G6PD activity and karyotype with prognostic assessment clearly indicated the association of (s) high percentage of chromosomal abnormalities especially translocations, (b) low survival and remission rates, with patients having decreased G6PD activity when compared to patients with normal activity in ANLL. The studies indicate that leucocyte G6PD may be useful as a diagnostic and prognostic tool.

Red cell enzymopathies in leukemias

Red cell glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK) levels were estimated in patients with leukemias, to see if there was a consistent enzyme defect and correlation of enzyme levels with stage of the disease with prognostic assessment. G6PD levels were found to be significantly increased or decreased in majority of the patients with acute leukemias. Increased activity was seen in majority of the patients with L1 and decreased activity in L2 subtype of acute lymphocytic leukemia (ALL). In chronic myeloid leukemia (CML) G6PD activity was consistently increased, with levels being highly elevated in chronic phase and moderately in blast phase. Variation in G6PD activity was found to be related to the stage of disease and was of prognostic significance. PK was found to be normal or decreased. Fetal haemoglobin levels were also estimated in 30 patients with leukemias and were found to be elevated in most patients. Red cell G6PD may be useful for staging of the disease, as prognostic indicator and predictor of relapse.

Reproductive epidemiology in sulfonamide factory workers

The reproductive performance of the wives of 300 men working in the pharmaceutical factory and exposed to sulfonamides was evaluated. The percentage of abortions, stillbirths, premature births, and live births among the wives of these workers and the frequency of congenital malformations in the offspring were recorded. The reproductive performance of 360 men and their wives who were not exposed to toxic chemicals, drugs, radiations, and so forth and who belonged to the same socioeconomic group served as the control population. There was a significant increase in the percentage of abortions and decrease in live births in the sulfonamide-exposed population when compared to controls.

Leukocyte glucose 6 phosphate dehydrogenase (G6PD) as prognostic indicator in children with acute lymphocytic leukemia

G6PD activity, estimated in 37 patients with acute lymphocytic leukemia (ALL) prior to therapy was found to be significantly decreased in 78.37% of the patients with ALL while it was normal in other patients. Variation in G6PD was found to be dependent on the percentage of myelocytes. Correlation analysis of leukocyte G6PD activity with karyotype indicated that patients with normal karyotype with normal G6PD activity had good prognosis while those with abnormal G6PD with abnormal karyotype had poor prognosis. Subjects with normal karyotype and abnormal G6PD and vice versa had intermediate prognosis. Thus the results clearly indicate that leukocyte G6PD may be used as a diagnostic and prognostic tool.