Preparation of sodium hyaluronate/dopamine/AgNPs hydrogel based on the natural eutetic solvent as an antibaterial wound dressing.

Baesd on previous researches, the natural deep eutectic solvent (DES) has enormous potential to be used in the fabrication of hydrogel wound dressing due to its outstanding properties including cytocompatibility, degradability and solubility. In order to further improve the antibaterial capacity of hydrogel, in the present study sodium hyaluronate (SH) and the natural DES were utilized to develop a novel hydrogel wound dressing by dopamine (DA) coated SH with in situ reduction of silver nanoparticles (DES-DASH@Ag). Furthermore, during the preparation process, we discovered for the first time that the DES can be used to fill the freeze-dried DASH to prepare a hydrogel (DES-DASH), which was promising to utilized in the fabrication of other hydrogels. Besides, the chemical and physical properties as well as wound healing capacity of the DES-DASH@Ag hydrogel were characterized. As a result, the DES-DASH@Ag hydrogel presented good cytocompatibility tested using NIH-3 T3 fibroblast cells, and prominent antibacterial effect against two types of bacteria infecting exposed wound. Furthermore, the hydrogel facilitated regeneration of mouse skin tissue in the wound area. The overall performance of DES-DASH@Ag hydrogel suggested that it could be a promising wound dressing in modern medicine.

Insight into the C-F bond mechanism of molecular analogs for antibacterial drug design.

The activities of biological molecules usually rely on both of intra-molecular and intermolecular interactions between their function groups. These interactions include interonic attraction theory, Van der Waal's forces and the function of geometry on the individual molecules, whether they are naturally or synthetic. The purpose of this study was to evaluate the antibacterial activity of C-F bond compound using combination of experiments verification and theoretical calculation. We target on the insect natural products from the maggots of Chrysomyis megacephala Fabricius. Based on density functional theory(DFT) and B3LYP method, a theoretical study of the C-F bond on fluoride was designed to explore compounds 2 and 4 antibacterial structure-activity relationship. With the progress in DFT, first-principle calculation based on DFT has gradually become a routine method for drug design, quantum chemistry and other science fields.

Comparison of bactericidal and cytotoxic activities of trichogin analogs.

Peptaibiotics are a group of membrane active peptides of fungal origin. They typically contain α-aminoisobutyric acid (Aib; 1-letter code, U) and other non-coded residues (Toniolo and Brückner, 2009; Neumann et al., 2015; Benedett et al., 1982) [1], [2], [3] stabilizing their helical structure. Peptaibols are peptaibiotics carrying a 1, 2-aminoalcohol at the C-terminus. When a fatty acid chain (of 8-10 carbon atoms) is present at their N-terminus, they are called lipopeptaibols (Toniolo et al., 2001; Degenkolb et al., 2003) [4], [5]. We found (Tavano et al., 2015) [6] that the lipopeptaibol trichogin displays no antibacterial effects up to 64 µM, against both Gram(-) and Gram(+) bacteria, but kills tumor and healthy human cells via a mechanism requiring both the C-terminal primary alcohol group and the N-terminal n-octanoyl moiety, with EC50s around 4-5 µM. However, the substitution of single Gly residues with Lys strongly improves anti-Gram(+) activity (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion et al., 2012) [6], [7], [8]. To further characterize the activity of trichogin analogs as antibiotics and cytotoxic agents, we here manipulated the peptide helix amphipathicity by means of two different substitutions: (i) Aib to Leu (De Zotti et al., 2012) [7] or (ii) multiple Gly to Lys changes (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion, Formaggio et al., 2012; De Zotti, Biondi, Peggion, De Poli et al., 2012) [6], [7], [8], [9]. The antibacterial activity against four commensal or opportunistic bacterial species and the cytotoxicity against a panel of 9 healthy and tumor-derived eukaryotic cell types (including erythrocytes) are reported as MIC and EC50 (MTS - [3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)]-2H-tetrazolium- reduction and LDH - lactate dehydrogenase - release assay).

Spectrum-efficient correlation pattern for quality evaluation of Scutellariae Radix / 中草药

Objective: To establish a new mode for quality evaluation of Scutellariae Radix objectively and effectively. Methods: To collect Scutellariae Radix extensively, prepare test liquid of every sample, examine its HPLC fingerprints and pesticide effectiveness, and then correlate the HPLC fingerprints with the inhibitory rates by mathematics. Results: The other 20 batches of Scutellariae Radix were examined. The bias proportions of the inhibitory rates between the ones calculated by the established mathematical model and the ones from experimental measurement were less than 10% in all, there were 15 samples whose bias proportions are less than 5%. Conclusion: The mathematic model can basically be used to evaluate the efficacy of Scutellariae Radix by HPLC fingerprints.

Mutational Screening of Zuelacmycin-producing Strain RL-2 / 微生物学通报

In this research, the zuelacmycin-producing strain Streptomyces venezuelaevar. qinlingensis RL-2 was used as original strain, the spore suspension of which was induced by UV, LiCl and the compound treatmeat (UV+LiCl) respectively. The zuelacmycin-high-yield strain UVL-108 was obtained by the treatment that the exposure time under UV irradition was 45 s and the concentration of LiCl was 0.4%. The heredity characters of mutant UVL-108 were stable in succesive six generations. The antibacterial activity and the fermentation titer of mutant UVL-108 were determinded by bidirectioned culture and mycelial linear growth respectively. The results demonstrated the antibaterial activity of mutant UVL-108 was improved by 77%, and the relative toxicity of fermentation to Phyricularia grisea was improved by two times compared with the original strain.