Stereoselective degradation of Diclofop-methyl during alcohol fermentation process

Stereoselective degradation of Diclofop-methyl (DM) has been found in alcohol fermentation of grape must and sucrose solution with dry yeast. A method was developed for separation and determination the two enantiomers of DM during the fermentation process by high-performance liquid chromatography based on cellulose tri-(3,5-dimethylphenyl-carbamate) chiral stationary phase. The results showed that the enantiomers of DM degraded following the first-order kinetics in the sucrose solution and the degradation of DM enantiomers in grape must were biphasic (slow-fast-slow process). In the sucrose solution, half lives of (+)-(R)-DM and (-)-(S)-DM were calculated to be 8.5 h and 3.1 h, respectively. In the grape must, half life of (+)-(R)-DM was calculated to be 41.7 h while (-)-(S)-DM was 16.0 h. The result was that (-)-(S)-enantiomer degraded faster than the (+)-(R)-enantiomer in both alcohol fermentation. The results also showed that the differences of the enantioselective degradation of DM depended on the fermentation matrix. DM was configurationally stable in fermentation, showing no interconversion of (-)-(S)- to (+)-(R)- enantiomer, and vice-versa.     

Dietary administration of zingerone to enhance growth, non-specific immune response, and resistance to Vibrio alginolyticus in Pacific white shrimp (Litopenaeus vannamei) juveniles

Zingerone, one of the active components of ginger, is a phenolic alkanone with antioxidant and anti-inflammatory properties. The effects of zingerone supplementation on the growth, immunity, and disease resistance of Pacific white shrimp (Litopenaeus vannamei) juveniles were studied. Four experimental diets, including a control diet (without zingerone enrichment) and 1, 2.5, and 5 mg zingerone (kg diet)⁻¹ were used. After 56 days of culture, shrimp fed diets supplemented with 1, 2.5, and 5 mg zingerone (kg diet)⁻¹ had significantly greater weight gain and feed efficiency than the controls. Furthermore, after 56 days of culture, shrimp fed all doses of the zingerone diet had higher survival rates compared to the controls after 24-72 h of challenge by the pathogen, Vibrio alginolyticus. Significantly increased phenoloxidase levels were found in shrimp fed the zingerone diets at all doses, and respiratory bursts, lysozyme and phagocytic activities of shrimp fed 2.5 and 5 mg zingerone (kg diet)⁻¹ also significantly increased. Neither the total hemocyte count nor superoxide dismutase activity of the experimental and control groups revealed significant differences at any dose. The results indicate that zingerone can be recommended as a supplement to shrimp feed to increase growth, immunity, and disease resistance against the pathogen, V. alginolyticus. Use of zingerone as appetizer and immunostimulant in shrimp is promising.     

Ovine prion protein genotype frequencies in northwestern China

Anti-scrapie breeding programs have been initiated to screen for scrapie-resistant sheep based on ovine prion protein gene (PRNP) genotypes at codons 136, 154 and 171 in many countries, especially European Union member states. However, investigation of sheep PRNP genotypes is limited in China, despite the large number of sheep breeds. We analyzed 432 sheep of five different breeds from farms in northwestern China, using PCR-single-strand conformational polymorphism analysis (PCR-SSCP); the corresponding haplotypes of different PRNP alleles were cloned. PRNP allele genotyping was done by amplification refractory mutation system-PCR (ARMS-PCR), according to the haplotype clones of each PRNP allele. The validity of ARMS-PCR was checked by PCR-SSCP. Another 325 unknown PRNP genotypes of other sheep breeds were analyzed according to the established ARMS-PCR. Genotype frequencies of 757 sheep were analyzed with these two methods to evaluate susceptibility to scrapie in northwestern China. Relevant mutations were also detected at other sites. Both methods were effective for ovine PRNP allele genotyping, and the results of the analysis completely coincided. Scrapie-resistant genotypes were found to be uncommon, indicating a high risk for ovine scrapie in northwest China. In addition to codons 136, 154 and 171, we found numerous new mutations; nearly half of them were previously unreported. These sheep populations have a high degree of polymorphism at the PRNP locus.     

Design,synthesis and antithrombotic evaluation of novel dabigatran prodrugs containing methyl ferulate

A novel series of prodrugs containing dabigatran and methyl (E)-3-(4-hydroxy-2-methoxyphenyl)propenoate (methyl ferulate) were synthesized. All of them reveal the effect of thrombin-induced anti-platelet aggregation in vitro. In addition, in vivo experiment shows that one of the target compounds, X-2 (ED₅₀ = 3.7 ± 1.0 μmol/kg) possesses a more potent activity for inhibiting venous thrombosis than that of dabigatran etexilate (ED₅₀ = 7.8 ± 1.5 μmol/kg).     

Prefused lysosomes cluster on autophagosomes regulated by VAMP8

Lysosome–autophagosome fusion is critical to autophagosome maturation. Although several proteins that regulate this fusion process have been identified, the prefusion architecture and its regulation remain unclear. Herein, we show that upon stimulation, multiple lysosomes form clusters around individual autophagosomes, setting the stage for membrane fusion. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein on lysosomes—vesicle-associated membrane protein 8 (VAMP8)—plays an important role in forming this prefusion state of lysosomal clusters. To study the potential role of phosphorylation on spontaneous fusion, we investigated the effect of phosphorylation of C-terminal residues of VAMP8. Using a phosphorylation mimic, we observed a decrease of fusion in an ensemble lipid mixing assay and an increase of unfused lysosomes associated with autophagosomes. These results suggest that phosphorylation not only reduces spontaneous fusion for minimizing autophagic flux under normal conditions, but also preassembles multiple lysosomes to increase the fusion probability for resuming autophagy upon stimulation. VAMP8 phosphorylation may thus play an important role in chemotherapy drug resistance by influencing autophagosome maturation.Subject terms: Cancer therapeutic resistance, Membrane fusion     

菌根真菌的生理生态功能

菌根真菌是土壤中重要生物成员之一,不仅具有丰富的遗传多样性和物种多样性,其功能也是丰富多样,主要体现在：1）影响陆生植物起源、进化、演化与分布;2）促进植物的生长发育;3）提高植物的抗逆性;4）修复污染与退化土壤、改善土壤质量与健康状况;5）促进农林牧业的生产;6）保持生态平衡、稳定生态系统及其可持续生产力.随着技术发展和研究的深入,菌根真菌新功能将会不断被发现.