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This article describes how a natural alkaloid allocryptopine (ALL) is able to differentiate two forms of biologically relevant human telomeric (htel22) G-quadruplex DNAs (GQ-DNA) depending on the presence of K+ and Na+ ions by steady-state and time-resolved spectroscopic techniques. For both interactions, predominant involvements of static-type quenching mechanism with the negligible influence of dynamic collision are established by UV–vis absorption and fluorescence emission study, which is further supported by fluorescence lifetime measurements. ALL exhibits appreciable affinity toward both GQ-DNAs. Both the mixed-hybrid (3 + 1) quadruplex structures in K+ ions and the basket-type antiparallel quadruplex structure under Na+ condition are converted to parallel types in the presence of ALL. Fluorescence intercalator displacement assay experiment revealed modest selectivity of ALL to both quadruplexes over duplex DNA along with higher selectivity for antiparallel types among the two quadruplexes via groove and/or loop binding, which is distinct from the conventional π-stacking of the ligands on external G-quartets. ALL stabilized both GQ-DNA topologies moderately. The differences in the dynamics of ALL within both DNA environments have been demonstrated vividly by time-resolved anisotropy measurements using the wobbling-in-cone model. These results suggest groove binding with antiparallel G-quartet with high affinity and moderate loop binding with mixed-hybrid G-quartet accompanied by the partial end stacking additionally in both of the cases. Our conclusions are further supported by steady-state anisotropy measurements and molecular docking. The present investigation can be used in the development of a biocompatible antitumour/anticancer agent targeting particular GQ-DNA conformation.

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The objective of land use planning is to make decisions on land use in such a way that the natural resources are put to the most beneficial use for man, while ensuring sustainability and conserving ecosystem. Each plant species requires specific soil-site conditions for its optimum growth. For rationalizing land use, the soil-site suitability for different crops needs to be determined. In the present investigation, soil-site suitability evaluation was carried out for paddy, maize, turmeric and mango crops of Nizamabad district of Telangana. The spatial database was generated using IRS-1D LISS-III satellite data. The spatial database and soil properties were integrated and analysed for the evaluation of suitability class of above crops using FAO guidelines in Geographical Information system (GIS) environment. The results indicated that out of total geographical area of 7,06,084 ha of the district 53.5 per cent area was moderately suitable to paddy, 50.6 per cent area was marginally suitable for maize, and 13.1 per cent was moderately suitable for turmeric, while 40.4 per cent of area was marginally suitable for mango.