Fabrication of nanoparticles from a synthesized peptide amphiphile as a versatile therapeutic cargo for high antiproliferative activity in tumor cells.

Nanoparticles with encapsulated small molecules have attained vital importance in anticancer research. Peptide-based nanoparticles show their versatility in drug delivery due to their excellent biocompatibility and nontoxic nature. We demonstrate here the design and fabrication of peptide-based nanoparticles as dual-therapeutic cargo for the controlled release of hydrophilic 5-Fluorouracil (5Fu) and hydrophobic camptothecin (CPT), simultaneously. The covalent conjugation of 5Fu with the peptide, through a stimuli-responsive linker, provided better control over the release of 5Fu and dramatically reduced the possibility of leaching of the small molecule. As anticipated, the peptide-5Fu nanoparticles were efficient to encapsulate a second chemotherapeutic molecule CPT in its hydrophobic region. The stimuli-responsive release of 5Fu was carefully monitored by HPLC, NMR, and UV-visible spectroscopy. On the other hand, the release of the hydrophobic drug CPT from the nanoparticles was determined to be in a diffusion-controlled fashion. Assessment of performance in human cervical HeLa cell lines demonstrated the peptide-drug nanoparticles to be highly nontoxic. Whereas, the simultaneous release of the two antitumor agents, in a controlled manner, resulting in rapid antiproliferation of the tumor cells.

Folding and stability of recombinant azoreductase enzyme from Chromobacterium violaceum.

Azoreductase from Chromobacterium violaceum was characterized biophysically using experimental and computational tools. The in-silico docking and cross-linking experiments using glutaraldehyde suggest dimeric nature of the enzyme. The enzyme structure was modelled and also studied using circular dichroism (CD) spectroscopy which suggests 40% α- helix, 30% ß- sheet and 30% random coils. In the modelled structure of the azoreductase, the cofactor flavin mononucleotide (FMN) binding energy was -3.8 kJ/mol. The binding of FMN affects the azoreductase-cofactor complex stability. The stability-folding studies indicate that the cofactor, FMN is required for folding, stability and activity. Overall, the data provides interesting insight into stability and biophysical parameters of the azoreductase protein.

Arginylation regulates adipogenesis by regulating expression of PPARγ at transcript and protein level.

Protein modification by arginylation regulates protein stability, function and interaction. The loss of arginylation disrupts a diverse set of fundamental cellular processes from proliferation to death. In the current study, role of arginylation in cell differentiation is investigated. Using in vitro preadipocyte differentiation model, it was observed that the inhibition or knockout (KO) of arginyltransferase 1 (ATE1) severely hindered differentiation of preadipocytes into mature adipocytes. Absence of arginylation inhibited expression of two key adipogenic transcription factors PPARγ and C/EBPα, and their downstream adipogenic genes (FABP4, GLUT4, PLN1). Arginylation did not affect the induction of C/EBPß and C/EBPδ, the up-stream regulators of PPARγ gene. However, absence of arginylation affected PPARγ protein expression, independent of its transcript level. The constitutive expression of PPARγ1 protein in Ate1 KO cells as well as ATE1 inhibitor treated wild type cells were dampened due to increased proteasome mediated degradation of PPARγ1 in the absence of arginylation in the cells. Taken together these observations suggested arginylation mediated transcriptional regulation of PPARγ and C/EBPα was downstream of C/EBPß and C/EBPδ, and that the arginylation mediated regulation of PPARγ protein expression may play a role in this process. The inhibition of arginylation in mature adipocytes also reduced expression of lipogenesis genes and decreased fat accumulation in differentiated adipocytes. Thus, the current study shows that arginylation is essential for preadipocyte differentiation and maturation which are thought to be key factors in the maintenance of adipose tissue homeostasis.

Biochemical characterization of a stable azoreductase enzyme from Chromobacterium violaceum: Application in industrial effluent dye degradation.

The presence of dye, including azo functional group (NN) containing dyes, in industrial waste water is one of the major causes of water pollution. This report showcases the functional role of azoreductase from Chromobacterium violaceum (MTCC No: 2656) as a valuable enzyme for degradation of azo dyes. The enzyme was cloned, expressed, purified and biochemically characterized and further tested for degradation efficiency of azo group containing dyes like methyl red, amaranth and methyl orange. The degraded azo dye products (metabolites) resulted by the action of azoreductase enzyme had reduced toxicity on fibroblast cell lines (L929) as compared to raw and intact dye. Further, good stability of the enzyme makes it more suitable for various applications related to the degradation and decolourisation of effluent dyes.

Geobacillus yumthangensis sp. nov., a thermophilic bacterium isolated from a north-east Indian hot spring.

A thermophilic, spore-forming, rod-shaped bacterium isolated from the Yumthang hot spring in North Sikkim, India was subjected to taxonomic studies. The thermophilic bacterial isolate was designated as strain AYN2T. Cells were Gram-stain-positive, aerobic, motile, rod-shaped, catalase-positive and methyl red-negative. Strain AYN2T was able to grow in the pH range from 6 to 10 (optimum, pH 7.5-8.0), at 40-70 °C (60 °C) and in NaCl concentrations of 0-4 % (1 %). The major cellular fatty acids were iso-C15 : 0 (12.8 %), iso-C16 : 0 (13.9 %) and iso-C17 : 0 (13.8 %). No matches were found in the rtsba6 Sherlock libraries. The G+C content of the genomic DNA was 42.11 mol%. Based on phylogenetic analysis of the 16S rRNA gene sequences, strain AYNT showed highest sequence similarity to the type strain of Geobacillus toebii (96 %). However, the phenotypic properties of strain AYN2T were clearly distinct from those of G. toebii and related species. On the basis of polyphasic analysis, strain AYN2T represents a novel species in the genus Geobacillus, for which the name Geobacillus yumthangensis sp. nov. is proposed. The type strain is AYN2T(MTCC=12749=KCTC=33950= JCM 32596).

Measurement and Prediction of Thermal Conductivity of Nanofluids Containing TiO2 Nanoparticles.

In this paper, experimental results on thermal conductivity of TiO2-Water, TiO2-Ethylene Glycol and TiO2-Engine Oil nanofluids in concentration range between 0.25 to 2 volume percent and temperature range of 10­70 °C is presented. Results show that thermal conductivity of nanofluids increases with increasing concentration and lower enhancement is observed with temperature as compared with concentration. Maximum enhancements are 9.3%, 15% and 8.9% for 2% volume of TiO2 nanoparticles at 70 °C for TiO2-Water, TiO2-Ethylene Glycol and TiO2-Engine Oil nanofluids respectively. 4-input and 1-output Artificial Neural Network (ANN) approach is used to predict thermal conductivity of nanofluids. Experimental results obtained were compared with some theoretical models and ANN approach. It is observed that ANN approach gives better predictions and is in good agreement with experimental results.