2020) Development of silver nanoparticle-based hydrogel composites for antimicrobial activity, Green Chemistry Letters and Reviews, 13:1, 34-40, ABSTRACT Antimicrobial function of Ag nanoparticles (NPs) has a strong correlation with the released Ag + cations that are produced by oxidation of Ag NPs in a solution state under ambient condition. Therefore, in order to develop anti-infective materials for biomedical applications, one needs to include Ag NPs inside biocompatible materials, which can allow slow release of Ag + cations. Hydrogels of natural polymers could be an ideal choice for the purpose because (a) the physicochemical properties of hydrogels resemble with biological tissue, and (b) the inclusion of Ag NPs inside hydrogels prevents the direct release of Ag NPs, while allowing the release of Ag + cations out of the hydrogels. In this regard, we present a simple strategy for producing Ag NPscontaining hydrogel based on natural alginate polymers. The chemical modification of alginate, blending with Ag NPs, gelation by photo-crosslinking process have been discussed in connection with antimicrobial reaction on model bacterium.

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Lycopene cyclase converts lycopene to beta-carotene by catalyzing the formation of two beta-rings at each end of the linear carotene structure. This reaction takes place as a two-step reaction in which both sides of of the lycopene molecule are cyclized into beta-carotene rings via the monocyclic gamma-carotene as an intermediate. The crtY gene coding for lycopene cyclase from Paracoccus haeundaensis consists of 1,158 base pairs encoding 386 amino acids residues. An expression plasmid containing the crtY gene (pET44a-CrtY) was constructed and expressed in Escherichia coli, and produced a recombinant protein of approximately 43 kDa, corresponding to the molecular mass of lycopene cyclase. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to lycopene cyclase. We also determined the lycopene substrate specificity and NADPH cofactor requirements of the purified protein. The Km values for lycopene and NADPH were 3.5 microM and 2 mM, respectively. The results obtained from this study will provide a wider base of knowledge on the enzyme characterization of lycopene cyclase at the molecular level.

Prodigiosin, a member of natural red pigment family, is produced by Serratia marcescens, and characterized by a common pyrrolylpyrromethane skeleton. This pigment has been reported with the effects of anticancer, immunosuppressant, antifungal, and algicidal activities. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital infections. In this study, anti-MRSA properties of prodigiosin isolated from Serratia sp. PDGS 120915 were investigated. We identified and purified prodigiosin using high performance liquid chromatography (HPLC) and evaluated anti-MRSA activity. Purified prodigiosin inhibited the growth of MRSA. The minimum inhibitory concentrations (MICs) of prodigiosin were determined to 32 μg/ml against the MRSA strains. Fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were indicated synergistic effects of prodigiosin on MRSA.

Prebiotics and probiotics have gained much attention in the pursuit of a healthy life. Recently, postbiotics have been spotlighted as next-generation compounds that can improve health. Postbiotics are designated into non-viable, inactivated, and ghost probiotics, and linked to several health benefits for the gut, immune system, and various other aspects of health. This study investigated the anti-proliferation effects of postbiotics against HT-29 cells, a colon cancer cell line. The postbiotics were produced by the ultrasonication method from two Lactobacillus strains (Lactobacillus sp. La1, and La2) and designated to Pobt-La1 and Pobt-La2, respectively, and non-viability was confirmed on the plate media. The anti-proliferation effect was concentration-dependent. The HT-29 cells showed viabilities of 39% and 49% when treated with 300 µL/mL of Pobt-La1 and Pobt-La2, respectively. During observation of the morphological changes of HT-29 cells when treated with IC50, a cell nucleus was not observed but cell condensation was observed. Moreover, in comparison with the control group, a reduced number of cells were observed. Based on these results, it considered that the postbiotic compounds from Lactobacillus La1 and La2 could provide crucial information in the development of anticancer research. Through further research, it would be beneficial to investigate the possibility of using these postbiotics (Pobt-La1 and -La2) as an anticancer drug.