Camptothecin (CPT), the derivatives of which are used clinically for the treatment of metastatic colon cancer, is isolated from intact plants that can be subjected to environmental fluctuations. In vitro cultures may be an alternate and continuous source for year-round production of CPT. Since CPT production by undifferentiated cell cultures is low, differentiated tissues such as root cultures may be a viable alternate source for CPT production. Hairy roots were induced in Ophiorriza rugosa, a source of CPT, using Agrobacterium rhizogenes strain LBA9402. The hairy roots, when cultured in light, showed spontaneous regeneration of shoots. Analysis of CPT levels in the hairy roots and in vitro-grown transformed shoots revealed 0.009% d.w. and 0.012% d.w., respectively.
Abstract Immobilized callus cultures of Tinospora cordifolia (Willd) Miers ex Hooks and Thoms were investigated to find out the combined effect of elicitation, cell permeabilization with chitosan and in situ product recovery by polymeric neutral resin‐like Diaion HP 20. In this study, callus cultures of T. cordifolia were immobilized using sodium alginate and calcium chloride and the beads were cultured in Murashige and Skoogapos;s basal medium along with benzyl adenine (BA), 2,4‐dichlorophenoxy acetic acid (2,4‐D) and 3% sucrose. The immobilized cultures, when subjected to elicitation and cell permeabilization with chitosan and in situ removal of the secondary metabolites by addition of resin, showed a 10‐fold increase in production of arabinogalactan (0.490% dry weight) as compared to respective controls devoid of resin and chitosan. This indicates that in situ adsorption may have reduced the feedback inhibition caused by accumulation of secondary metabolites in the media, while the dual effect of elicitation and cell permeabilization by chitosan may have released the intracellular (secreted) berberine and the polysaccharide arabinogalactan, respectively.
Uranium uptake, translocation and its effects on leaf anatomy in vetiver grass (Vetiveria zizanioides L. Nash) grown in hydroponics were investigated at a wide range of concentrations. At concentrations below 200 ppm (1, 5, 25, 100, and 200 ppm) almost 90-95% of uranium was depleted from the medium within 3 days of treatment, while at other concentrations viz., at 318, 500, 619, 1,000, 5,000, 7,500, and 11,900 ppm, it reached a maximum between 7 and 14 days, with a marginal increase in the depletion thereafter. Most of the uranium could be recovered from plants at concentrations below 200 ppm. On the contrary, a significant reduction in the recovery of uranium was noticed at higher concentrations and the percentage of recovery dropped from 82% at 318 ppm to 35% at 11,900 ppm. While most of the uranium taken up by the plants could be recovered from roots at lower concentrations, a preferential translocation of the element to shoot occurred at concentrations beyond 1,000 ppm. Histological studies of leaves from plants treated with 1,000 ppm uranium displayed the formation of multilayered cells between the epidermis and vascular bundles on the adaxial side in the distal regions of the leaves. The plants were also found to tolerate and survive the radiological and chemical constituents of both uranium mill tailings soil as well as various effluents of uranium mine and mill operations. Further, they could also survive in uranium ore containing 600 ppm of triuranium octoxide (U3O8) and could withstand the amendment of ore with citric acid. The ability of vetiver to take up uranium from solutions to high levels and its survival in effluents, mill tailings soil, and ore coupled with its ecological characteristics makes it an ideal plant for phytoextraction of uranium.
RAPD markers were employed to assess genetic relatedness in seven Gossypium species, which included G. hirsutum CMS lines and cultivars, G. arboreum GMS lines, cultivars, and wild species, G. raimondii, G. bickii, G. thurberii, G. captis-viridis and G. anomalum, Out of 45 RAPD primers tested, 24 oligonucleotide primers yielded monomorphic amplified products or did not show any amplification product in some of the genotypes. The remaining 21 primers amplified a total of 168 fragments with an average of 9.8 fragments per primer. Out of the 11 genotypes studied, G. arboreum (G 27) produced the maximum number of DNA amplified fragments and G. raimondii produced the lowest number. On the basis of similarity coefficients cluster analysis was performed using UPGMA method. Cluster analysis resulted in 4 main cluster groups. Cluster one contained two subclusters IA and IB. Subcluster IA consisted of G. hirsutum lines, which represent AD genome. Subcluster IB contained G. arboreum genotypes with A genome. Cluster II consisted of G. raimondii, G. thurberii, which belong to the D genome. Cluster III consisted of only G. bickii representing the C genome and cluster 4 consisted of G. anomalum and G. captis-viridis representing the B genome. The clustering pattern obtained using RAPD analysis in the present study is in conformity with available information based on cytogenetic relationship.
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