Search

Purification of valuable engineered proteins and enzymes can be laborious, costly, and generating large amount of chemical waste. Whilst enzyme immobilization can enhance recycling and reuse of enzymes, conventional methods for immobilizing engineered enzymes from purified samples are also inefficient with multiple-step protocols, regarding both the carrier preparation and enzyme binding. Nickel ferrite magnetic nanoparticles (NiFe2O4 MNPs) offer distinct advantages in both purification and immobilization of enzymes. In this work, we demonstrate the preparation of NiFe2O4 MNPs via a one-step solvothermal synthesis and their use in direct enzyme binding from cell lysates. These NiFe2O4 MNPs have showed an average diameter of 8.9 ± 1.7 nm from TEM analysis and a magnetization at saturation (Ms) value of 53.0 emu g–1 from SQUID measurement. The nickel binding sites of the MNP surface allow direct binding of three his-tagged enzymes, d-phenylglycine aminotransferase (d-PhgAT), Halomonas elongata ω-transaminase (HeωT), and glucose dehydrogenase from Bacillus subtilis (BsGDH). It was found that the enzymatic activities of all immobilized samples directly prepared from cell lysates were comparable to those prepared from the conventional immobilization method using purified enzymes. Remarkably, d-PhgAT supported on NiFe2O4 MNPs also showed similar activity to the purified free enzyme. By comparing on both carrier preparation and enzyme immobilization protocols, use of NiFe2O4 MNPs for direct enzyme immobilization from cell lysate can significantly reduce the number of steps, time, and use of chemicals. Therefore, NiFe2O4 MNPs can offer considerable advantages for use in both enzyme immobilization and protein purification in pharmaceutical and other chemical industries. [ABSTRACT FROM AUTHOR]

Nano-scale extracellular vesicles are lipid-bilayer delimited particles that are naturally secreted by all cells and have emerged as valuable biomarkers for a wide range of diseases. Efficient isolation of small extracellular vesicles while maintaining yield and purity is crucial to harvest their potential in diagnostic, prognostic, and therapeutic applications. Most conventional methods of isolation suffer from significant shortcomings, including low purity or yield, long duration, need for large sample volumes, specialized equipment, trained personnel, and high costs. To address some of these challenges, our group has reported a novel insulator-based dielectrophoretic device for rapid isolation of small extracellular vesicles from biofluids and cell culture media based on their size and dielectric properties. In this study, we report a comprehensive characterization of small extracellular vesicles isolated from cancer-patients' biofluids at a twofold enrichment using the device. The three-fold characterization that was performed using conventional flow cytometry, advanced imaging flow cytometry, and microRNA sequencing indicated high yield and purity of the isolated small extracellular vesicles. The device thus offers an efficient platform for rapid isolation while maintaining biomolecular integrity. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor 21 (FGF21) has pharmaceutical potential against obesity-related metabolic disorders, including non-alcoholic fatty liver disease. Since thermal stability is a desirable factor for therapeutic proteins, we investigated the thermal behavior of human FGF21. FGF21 remained soluble after heating; thus, we examined its temperature-induced structural changes using circular dichroism (CD). FGF21 showed inter-convertible temperature-specific CD spectra. The CD spectrum at 100 °C returned to that at 20 °C when the heated FGF21 solution was cooled. Through loop swapping, the connecting loop between β10 and β12 in FGF21 was revealed to be associated with the unique thermal behavior of FGF21. According to surface plasmon resonance (SPR) experiments, in vitro cell-based assays, and model high-fat diet (HFD)-induced obesity studies, heated FGF21 maintained biological activities that were comparable to those of non-heated and commercial FGF21s. Based on sequence comparison and structural analysis, five point-mutations were introduced into FGF21. Compared with the wild type, the heated FGF21 variant displayed improved therapeutic potential in terms of body weight loss, the levels of hepatic triglycerides and lipids, and the degree of vacuolization of liver in HFD-fed mice. [ABSTRACT FROM AUTHOR]

Selective isolation of soil Actinobacteria was undertaken to isolate a new class of antibiotics and bioactive molecules. A Streptomyces sp. PSAA01 (= MTCC 13,157), isolated from soil of Eastern Himalaya foothill was cultivated on a large scale for the production of the antimicrobial SM02. It has been found that the maximum amount of SM02 produced while PSAA01 was grown in ISP-2 medium (pH 7.0) for 7 days at 30 °C in shaking (180 rpm) condition. A significant zone of inhibition against Staphylococcus aureus MTCC 96 has been found with the crude cell-free culture media (50 µL) of 7 days grown PSAA01. After the purification and chemical structural characterization, we found that SM02 is a new antimicrobial having 746 dalton molecular weight. The compound SM02 contains pyrimidine moiety in it and is produced by a species of Streptomyces and thus we have named this antibiotic pyrimidomycin. The antimicrobial spectrum of pyrimidomycin has been found to be restricted in Gram-positive organisms with a MIC of 12 µg/mL. SM02 was found active against Mycobacterium sp. and also multi-drug resistant Gram-positive bacteria with similar potency and found to disrupt the bacterial cell wall. Pyrimidomycin also showed significant impairment in the biofilm formation by S. aureus. Furthermore, pyrimidomycin showed synergy with the most used antibiotic like ampicillin, vancomycin and chloramphenicol. Pyrimidomycin did not have cytotoxicity towards human cell lines indicating its limited activity within bacteria. [ABSTRACT FROM AUTHOR]