A versatile tool in controlling aggregation and Ag nanoparticles assisted in vitro folding of thermally denatured zDHFR.

BACKGROUND: Proteins have tendency to form inactive aggregates at higher temperatures due to thermal instability. Maintenance of thermal stability is essential to gain the protein in sufficient quantity and biologically active form during their commercial production. METHODS: BL21-DE3 Rosetta E. coli cells which contains plasmid pET43.1a vector was used for producing zDHFR protein commercially. The purification of N-terminal Histidine tagged zDHFR was performed by Immobilized Metal Ion chromatography (IMAC). Investigations were performed in existence and non existence of Silver nanoparticles (AgNPs). The inactivation kinetics of zDHFR in existence and non existence of AgNPs were monitored over a range of 40-80 °C as monitored by UV-Visible absorption spectroscopy. RESULTS: The protein completely lost its activity at 55 °C. Kinetics of inactivated zDHFR follows first order model in presence and absence of AgNPs. Decrease in rate constant (k) values at respective temperatures depicts that AgNPs contribute in the thermostability of the protein. AgNPs also assists in regaining the activity of zDHFR protein. CONCLUSIONS: AgNPs helps in maintaining thermostability and reducing the aggregation propensity of zDHFR protein. GENERAL SIGNIFICANCE: Result explains that AgNPs are recommended as a valuable system in enhancing the industrial production of biologically active zDHFR protein which is an important component in folate cycle and essential for survival of cells and prevents the protein from being aggregated.

DNA barcoding and Taxonomic account on some selected species of subfamily Plusiinae (Lepidoptera: Noctuidae) from India.

This study represents a detailed taxonomic account of 31 species of Plusiinae (Lepidoptera: Noctuidae) from India. The survey and collection of 39 localities from different regions of India between 2015 and 2018. The tribe Argyrogrammatini Eichlin Cunningham, 1978 with Ctenoplusia Dufey, 1970 was the most species rich genera with seven species, followed by Thysanoplusia Ichinose, 1973 and Chrysodeixis Hubner, 1821 with four and three species respectively. Among 31 species, 15 species are commonly found in Himalayan regions and while other species were distributed from subtropical to tropical region. Five species, T. orichalcea (Fabricius, 1775), Chrysodeixis eriosoma (Doubleday, 1843), C. acuta (Walker, 1858), C. chalcites (Esper, 1789), Trichoplusia ni (Hubner, 1803) are widespread throughout India and reported as serious crop pests. Present study also revealed range expansion of four species viz., Dactyloplusia impulsa (Walker, 1865), Ctenoplusia mutans (Walker, 1865), Ctenoplusia tarassota (Hampson, 1913) and Zonoplusia ochreata (Walker, 1865). Systematic accounts of all 31 species are discussed here with adult images, species diagnostic characters, collection localities, detailed distributions and reported larval host plants. In addition to morphological studies, for the first time, a preliminary barcode library for 25 species of Indian Plusiinae with average intra-specific distance (%), maximum intra-specific distance (%) and distance to nearest neighbor (%) for individual species is provided. Among 25 species, four species barcode data (Ctenoplusia mutans, C. kosemponesis, Plusiopalpa adrasta, Sclerogenia jessica) are novel to world and 18 species barcode sequences were novel to India.