高效液相色谱法测定海胆黄中岩藻黄质与岩藻黄醇

目的 建立高效液相色谱法同时测定海胆黄中岩藻黄质及岩藻黄醇的方法。方法 采用高效液相色谱法,色谱柱为Hypersil ODS C18(4.6 mm×250 mm,５μｍ),流动相为甲醇-水(90:10) ,检测波长为449 nm,流速１mL.min^－１,进样量10 μＬ。结果 岩藻黄质与岩藻黄醇在此色谱条件下获得良好分离, 岩藻黄质在0.88～56 μg/mL范围内呈良好线性 (y = 102.75x + 4.4072,r = 0.9999, 平均加样回收率为97.76%, RSD 1.88%),岩藻黄醇在0.88～56 μg/mL范围内呈良好线性 (y = 92.906x + 2.2318,r = 0.9999,平均加样回收率为95.28%, RSD 1.85%)。结论 本方法准确、可靠, 可用于海胆等生物样品中岩藻黄质及岩藻黄醇的含量测定。     

Distribution and risk assessment of heavy metals in the economic fish of the Southern Fujian Province

The distribution and risk assessment of heavy metals (Pb, Cu, Cr, Zn, Cd, As and Hg) in the economic fish of the Southern Fujian Province was acquired. The Cd content was below the detection limit. 53.5% of As and 26.7% of Hg were lightly polluted, but the indices of P_in (Nemero comprehensive pollution index) and MPI (metal pollution index) both indicated no pollution. The indices of EDI (estimated daily intake) and THQ (target hazard quotient) both indicated no non-carcinogenic risk of HMs. The index of R_i (average annual cancer risk) verified no carcinogenic risk for Pb and acceptable risk for As. Furthermore, molecular docking results revealed As may have significant reproductive toxicity to humans. Our findings serve to heighten an awareness of economic fish consumption and provide a reference for marine environmental management and food security in study area.     

Preparation and characterization of squid pen chitooligosaccharide–epigallocatechin gallate conjugates and their antioxidant and antimicrobial activities

Chitooligosaccharide (COS) and epigallocatechin-3-gallate (EGCG) at various concentrations were used for the preparation of COS–EGCG conjugates. The highest total phenolic content (TPC), representing the amount of EGCG conjugated, was obtained for 1 wt% COS together with EGCG at 0.5 wt% (C1-E0.5-conjugate) or 1.0 wt% (C1-E1.0-conjugate) (66.83 and 69.22 mg EGCG per g sample, respectively) (p < 0.05). The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities (DRSA and ARSA, respectively) and ferric reducing antioxidant power (FRAP) of all the samples showed similar trends with TPC. The C1-E0.5-conjugate had higher DRSA, ARSA, FRAP and oxygen radical absorbance capacity (ORAC) values than COS (p < 0.05). Similarly, the antimicrobial activity of COS increased when conjugated with EGCG (p < 0.05). FTIR, ¹H-NMR and ¹³C-NMR analyses confirmed the successful grafting of EGCG with COS. Therefore, 1 wt% COS and 0.5 wt% EGCG were used for the production of a conjugate with augmented antioxidant activity, which could be used to retard lipid oxidation of fatty foods.

Chitooligosaccharide from squid pen showed increases in both antioxidant and antimicrobial activities via conjugation with epigallocatechin-gallate (EGCG).     

2株海洋来源真菌共培养产物的研究

摘要：目的 对2株海洋来源真菌Stachybotrys sp. 3A00409与Aspergillus sclerotiorum MXH-17的共培养产物进行化学成分和生物活性研究。方法 采用溶剂萃取、柱色谱层析及半制备HPLC等方法对2株真菌共培养发酵产物的差异部分进行靶向化学分离,通过理化性质及波谱学方法并参阅文献进行化合物结构鉴定,并初步评价其细胞毒和抑菌活性。结果 以大米静置共培养作为目标培养模式进行大量发酵,经过目标化合物靶向分离,得到6个单体化合物,结构鉴定为二聚萘并-?-吡喃酮类化合物Asperpyrone A（1）、Fonsecinone A（2）、Asperpyrone C（3）、Aurasperone A（4）、Dianhydro-aurasperone C（5）和异色酮类化合物(7S, 8S)-sclerotinin A （6）。抑菌实验结果显示化合物1对大肠杆菌Escherichia coli表现出弱的抑菌活性,MIC为39.7 μmol/L。结论 共培养刺激微生物代谢产物产生是提高微生物化学多样性的潜在有力工具,本研究从海洋来源真菌Stachybotrys sp. 3A00409与Aspergillus sclerotiorum MXH-17的共培养产物中分离得到了单菌培养中未发现过的5个二聚萘并-?-吡喃酮类和1个异色酮类化合物。     

Mechanisms of quinolone resistance in Aeromonas species isolated from humans,water and eels

Mechanisms of resistance were determined in 33 quinolone-resistant isolates of the species Aeromonas hydrophila, Aeromonas caviae, Aeromonas media, Aeromonas salmonicida, Aeromonas popoffii and Aeromonas veronii, recovered from humans, freshwater and eels. The quinolone resistance-determining regions (QRDRs) of gyrA and parC genes were sequenced in these resistant strains, as well as in 8 quinolone-sensitive Aeromonas used as controls. All quinolone-resistant Aeromonas carried point mutations in the gyrA QRDR at codon 83, respectively giving rise to substitutions Ser⁸³ → Ile (32 strains) or Ser⁸³ → Val (1 strain). Almost half of these isolates (48%) carried additional point mutations in the gyrA QRDR at codon 92 and/or in the parC QRDR at codon 80 corresponding to substitutions Leu⁹² → Met and Ser⁸⁰ → Ile. In all cases, MICs of quinolones were determined in the presence and absence of the efflux pump inhibitor phenylalanine-arginine β-naphthylamide (PAβN). Addition of PAβN had no effect on the levels of resistance observed in these isolates. In conclusion, the mechanism of quinolone resistance in the Aeromonas isolates studied was related to mutations in QRDR regions of gyrA and parC genes, with little obvious involvement of pumps inhibited by PAβN.