Streptococcus agalactiae, a highly contagious mastitis pathogen, caused huge economic losses; meanwhile, repeated use of antibiotics results in the emergence of serious antibiotic residues and drug resistance. Therefore, it is in great need to develop ecologically sustainable antimicrobial agents. In the study, the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and action mechanism of terpinen-4-ol against S. agalactiae was investigated to evaluate antibacterial activity of terpinen-4-ol. Results showed the MIC and MBC of terpinen-4-ol were 98 and 196 µg/mL, respectively. Time-kill curves displayed that the antibacterial activity of terpinen-4-ol was in a concentration-dependent manner. Transmission electron micrographs showed that the cell membrane and wall of S. agalactiae were damaged, and plasmolysis and chromatins were inconspicuous. Release of Ca and Mg proved that terpinen-4-ol could increase cell membrane permeability. And the release of lactate dehydrogenase (LDH) suggested that cell wall was destroyed. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and 4',6-diamidino-2-phenylindole (DAPI) staining results showed that terpinen-4-ol could affect the synthesis of protein and DNA. These results suggested that terpinen-4-ol might be used as candidate for treating S. agalactiae infection.

A bioassay-guided fractionation was performed to evaluate the anthelmintic activity of the crude extract fractions and osthole from Radix angelicae pubescentis against Dactylogyrus intermedius in goldfish (Carassius auratus) in vivo. Among four extracts (petroleum ether, ethyl acetate, acetone, and ethanol), only ethanol extract exhibited the best anthelmintic efficacy with 100% mortality of Dactylogyrus and no death of fish at the optimal anthelminthic concentration of 120 mg/L. Therefore, ethanol extract was subjected to column chromatography to obtain sixteen fractions. The activity was found in fraction F with 100% mortality of Dactylogyrus and no toxicity to fish at dose of 2.0 mg/L. A white crystal was isolated from fraction F and identified as osthole which exhibited the optimal activity with 100% mortality of Dactylogyrus at 1.6 mg/L had and no toxicity to fish at dose up to 6.2 mg/L. This is the first report on the isolation and identification of anthelmintic active compound from R. angelicae pubescentis against D. intermedius in goldfish (C. auratus) in vivo.

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This paper reports an improved fermentation process that includes simultaneous saccharification, detoxification, and cofermentation as steps for producing bioethanol. Rice straw was first steam exploded (SE) or butanone solution exploded (BSE) and then cofermented with Saccharomyces cerevisiae and Candida shehatae. To overcome the inhibitors, the exploded rice straw was continuously and slowly introduced into a 10 L ventilated fermenter. When the fermentation conditions were set to 1.0% initial dry matter, 10% total dry matter, addition rate of 120 mg/min, total fermentation time of 234 h, and dose of 0.1% (NH4)2SO4, yields of 25.8 g/100 g of dry matter ethanol and 88% total sugar use were obtained for BSE rice straw. The ethanol yields were not significantly different between detoxified materials and non-detoxified materials. Most of the furfural, hydroxymethylfurfural (5-HMF), acetic acid, and butanone were removed during the fermentation of non-detoxified materials, and the sugar concentrations were very low. The in situ detoxification and fermentation was effective and inexpensive when the pre-detoxification of exploded materials and the pre-adaptation of strains steps were omitted.