Bharathiar University

About: Bharathiar University is a education organization based out in Coimbatore, Tamil Nadu, India. It is known for research contribution in the topics: Thin film & Adsorption. The organization has 5812 authors who have published 8628 publications receiving 143934 citations. The organization is also known as: BU.

Construction of Novel Chloroplast Expression Vector and Development of an Efficient Transformation System for the Diatom Phaeodactylum tricornutum

Abstract: Plastids are ideal subcellular hosts for the expression of transgenes and have been successfully used for the production of different biopolymers, therapeutic proteins and industrial enzymes. Phaeodactylum tricornutum is a widely used aquatic feed species. In this study, we focused on developing a high-efficiency plastid expression system for P. tricornutum. In the plastid transformation vector, the site selected for integration was the transcriptionally active intergenic region present between the trnI and trnA genes, located in the IR (inverted repeat) regions of the plastid genome. Initially, a CAT reporter gene (encoding chloramphenicol acetyltransferase) was integrated at this site in the plastid genome. The expression of CAT in the transformed microalgae conferred resistance to the antibiotic chloramphenicol, which enabled growth in the selection media. Overall, the plastid transformation efficiency was found to be approximately one transplastomic colony per 1,000 microalgae cells. Subsequently, a heterologous gene expression cassette for high-level expression of the target gene was created and cloned between the homologous recombination elements. A TA cloning strategy based on the designed XcmI-XcmI sites could conveniently clone the heterologous gene. An eGFP (green fluorescent protein) reporter gene was used to test the expression level in the plastid system. The relatively high-level expression of eGFP without codon optimisation in stably transformed microalgae was determined to account for 0.12 % of the total soluble protein. Thus, this study presents the first and convenient plastid gene expression system for diatoms and represents an interesting tool to study diatom plastids.

Microwave Assisted Synthesis of Pure and Ag Doped SnO 2 Quantum Dots as Novel Platform for High Photocatalytic Activity Performance

Abstract: In this study, we report a simple and fast synthetic route to prepare pure and Ag doped SnO2 quantum dots via one step microwave irradiation method for the first time. Variety of analytical techniques including XRD, Raman, TEM, EDS, XPS, UV and PL were used to investigate the influence of Ag dopant concentration on structural, morphological, compositional and optical properties of SnO2 nanoparticles. The XRD pattern showed a dominant tetragonal rutile structure of both pure and Ag doped SnO2 and formed directly during the microwave irradiation process. TEM images revealed that quantum dots and the average particle size increases by Ag doping. The EDS and XPS results proved that the presence of silver as Ag3+ species. The optical properly of SnO2 was significantly improved and narrowing the band gap (3.54–3.09 eV) of pure SnO2 by Ag doping, which is confirmed through UV and PL results. The photocatalytic behavior of the catalyst powders were investigated using methylene blue and rhodamine B (RhB) as model organic pollutants. A maximum RhB degradation efficiency of 97.5% is achieved under visible light irradiation for Ag doped SnO2 catalyst. Furthermore, the Ag–SnO2 QDs catalyst demonstrates good reusability and stability after the seven cycles.