The phylogenetic relationships of the type strains of 16 Erwinia species were investigated by performing a comparative analysis of the sequences of the 16S rRNA genes of these organisms. The sequence data were analyzed by the neighbor-joining method, and each branch was supported by moderate bootstrap values. The phylogenetic tree and sequence analyses confirmed that the genus Erwinia is composed of species that exhibit considerable heterogeneity and form four clades that are intermixed with members of other genera, such as Escherichia coli, Klebsiella pneumoniae, and Serratia marcescens. Cluster I includes the type strains of Erwinia herbicola, Erwinia millltiae, Erwinia ananas, Erwinia uredovora, and Erwinia stewartii and corresponds to Dye's herbicola group. Cluster II consists of Erwinia persicinus, Erwinia rhapontici, Erwinia amylovora, and Erwinia cypripedii. Cluster III consists of Erwinia carotovora subspecies and Erwinia chrysanthemi and is characterized by the production of pectate lyases and cellulases. Erwinia salicis, Erwinia rubrifaciens, and Erwinia nigrifluens form the cluster that is most distantly related to other Erwinia species. The data from the sequence analyses are discussed in the context of biochemical and DNA-DNA hybridization data.
Optimization of the extraction procedure was performed to enhance the antioxidant activity and whitening effect of Sasa quelpaertensis Nakai extract using response surface methodology (RSM). The central composite design, a component of RSM, was utilized to optimize and validate the ethanol extract for antioxidant activity and the hot water extract for the whitening effect, respectively. Activities of antioxidant and whitening were determined by DPPH and tyrosinase inhibition assays. The antioxidant activity was notably influenced by ethanol concentration (p = 0.0344) more than other factors. The optimal conditions for the antioxidant effect were 54% ethanol concentration, 52 °C, and 3 h extraction time, yielding an antioxidant activity of 83.65±1.56%. On the other hand, the whitening effect was significantly impacted by ultrasonic irradiation time (p = 0.0175) compared to other factors. The optimal conditions for whitening were 41 °C, 1:19 of sample-to-solvent ratio, and 8 min of ultrasonic irradiation, achieving a tyrosinase inhibition activity of 51.00±1.80%. High-performance liquid chromatography (HPLC) analysis was conducted to identify compounds such as tricin with antioxidant activity and p-coumaric acid, arbutin with whitening effect under the optimized conditions. The results suggest that the optimized extracts from S. quelpaertensis could be utilized as beneficial cosmeceutical materials.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)
