Evolutionary divergence of the nuclear pore complex from fungi to metazoans

Nuclear pore complex (NPC) is the largest multimeric protein assembly of the eukaryotic cell, which mediates the nucleocytoplasmic transport. The constituent proteins of this assembly (nucleoporins) are present in varying copy numbers to give a size from ~ 60 MDa (yeast) to 112 MDa (human) and share common ancestry with other membrane‐associated complexes such as COPI/COPII and thus share the same structural folds. However, the nucleoporins across species exhibit very low percentage sequence similarity and this reflects in their distinct secondary structure and domain organization. We employed thorough sequence and phylogenetic analysis guided from structure‐based alignments of all the nucleoporins from fungi to metazoans to understand the evolution of NPC. Through evolutionary pressure analysis on various nucleoporins, we deduced that these proteins are under differential selection pressure and hence the homologous interacting partners do not complement each other in the in vitro pull‐down assay. The super tree analysis of all nucleoporins taken together illustrates divergent evolution of nucleoporins and notably, the degree of divergence is more apparent in higher order organisms as compared to lower species. Overall, our results support the hypothesis that the protein–protein interactions in such large multimeric assemblies are species specific in nature and hence their structure and function should also be studied in an organism‐specific manner.     

Larvicidal activity of Pseudocalymma alliaceum and Allium sativum against Culex quinquefasciatus (Say)

The larvicidal activity of the plant extracts Pseudocalymma alliaceum and Allium sativum were determined against Culex quinquefasciatus. The hexane extract of P. alliaceum and the petroleum ether extract of A. sativum exhibited larvicidal efficacy against Cx. quinquefasciatus larvae. Extracts of P. alliaceum resulted in concentrations that produced 50% mortality LC₅₀ and LC₉₀ values of 2.49 and 15.06 ppm, respectively, after 24 h and 1.16 and 8.45 ppm after 48 h. Extracts of A. sativum resulted in LC₅₀ and LC₉₀ values of 8.38 and 29.15 ppm after 24 h and 7.28 and 44.19 ppm after 48 h of exposure, respectively. The results indicate that the plant extract component(s) present in the hexane extract of P. alliaceum leaves demonstrated greater potential as an efficient larvicide than A. sativum against Cx. quinquefasciatus.     

Relative toxicity of different combinations of temephos and fenthion with Solanum xanthocarpum extract against anopheline larvae

The relative toxicity of different concentrations of temephos and fenthion with petroleum ether root extract of Solanum xanthocarpum (Schrader) at 1 : 1, 1 : 2 and 1 : 4 ratios was evaluated against Anopheles stephensi (Liston) larvae. All combinations exhibited antagonism at concentrations lower than LC₅₀ values and synergism at concentrations higher than their LC₉₀ values. A 1 : 1 product ratio was the most effective.