应用MRCO设计提取螺旋藻多糖的研究

采用单因素分组试验与计算机优化设计对钝顶螺旋藻水溶性多糖的提取、分离工艺条件进行了研究,比较了浸提温度、提取时间、浸提次数、水料比等因素对钝顶螺旋藻水溶性多糖分离提取的影响,选定适宜的提取工艺条件为：温度７５℃、提取时间２ｈ,水料比４３：！,乙醇体积为７５％,提取次数为２次,用Ｓｅｖａｇｅ法、ＳｅｐｈａｄｅｘＧ－２００柱层析法纯化螺旋藻多糖,使其纯度达到９６．８％,并肜纸层析法,紫外光谱对纯度进行     

响应面法对缢蛏粗多糖提取工艺的优化

以秦皇岛海域的缢蛏为原料,通过不同提取方法的比较,确定超声辅助酶解提取法为较优的多糖提取方法,并通过响应面法对缢蛏多糖提取工艺进行优化。试验结果表明,原料超声预处理30min后再进行酶解提取,在添加3.99%的木瓜蛋白酶、50.9℃、酶提8.94h条件下缢蛏多糖提取量达9.41mg/g(鲜)。该方法对研究海水贝类多糖功能性产品原料的选取及产品的开发与应用有重要意义。     

Optimization of cultivation conditions for enhancing biomass,polysaccharide and protein yields of Chlorella sorokiniana by response surface methodology

On the basis of multiple single‐factor studies, the best conditions for each factor were selected by comparison. Taking the biomass, polysaccharide and protein yields of chlorella as response values, the four‐factor and three‐level response surface design experiment was performed on four parameters that significantly affected the response values to further determine the optimal conditions. The optimal parameters of the culture process were nitrogen source (urea), carbon source (sodium carbonate), nitrogen concentration (15.80 mmol/L), carbon concentration (0.36 mmol/L), phosphorus concentration (0.2 mmol/L), magnesium concentration (0.33 mmol/L), calcium concentration (0.25 mmol/L), iron concentration (0.02 mmol/L), initial pH (7.0), inoculation amount (6%) and ventilation capacity (40 L/hr). According to this process, the biomass, polysaccharide and protein yield of Chlorella sorokiniana obtained from indoor culture were close to the predicted value, which were more than three times as much as before, reaching 3.58, 0.52 and 0.46 g/L respectively. Chlorella sorokiniana, which was cultured outdoor according to the optimized process, increased its biomass, polysaccharide and protein yield by more than 1.5 times. Chlorella sorokiniana was significantly different before and after optimized culture. This provides a good source for the research of polysaccharide and protein of C. sorokiniana and helps the further study of its structure and biological activity, which makes the further development of its function more possible.     

Preventive Effect of Depolymerized Sulfated Galactans from Eucheuma serra on Enterotoxigenic Escherichia coli-Caused Diarrhea via Modulating Intestinal Flora in Mice

In this work, the preventive effect of depolymerized sulfated polysaccharides from Eucheuma serra (DESP) on bacterial diarrhea by regulating intestinal flora was investigated in vivo. Based on the enterotoxigenic Escherichia coli (ETEC)-infected mouse diarrhea model, DESP at doses ranging from 50 mg/kg to 200 mg/kg alleviated weight loss and decreased the diarrhea rate and diarrhea index. Serological tests showed that the levels of inflammation-related factors were effectively suppressed. Furthermore, the repaired intestinal mucosa was verified by morphology and pathological tissue section observations. Compared with the model group, the richness and diversity of the intestinal flora in the DESP group increased according to the 16S rRNA high-throughput sequencing of the gut microbiota. Specifically, Firmicutes and Actinobacteria increased, and Proteobacteria decreased after DESP administration. At the family level, DESP effectively improved the abundance of Lactobacillaceae, Bifidobacteriaceae, and Lachnospiraceae, while significantly inhibiting the growth of Enterobacteriaceae. Therefore, the antimicrobial diarrhea function of DESP may be related to the regulation of intestinal microbiota.     

归芪多糖延缓细胞衰老的分子作用机制

以SIRT1和线粒体为切入点，采用分子生物学技术以及多种线粒体分析技术，深入探讨SIRT1和线粒体在衰老细胞中的作用，揭示归芪多糖延缓细胞衰老的分子作用机制。结果表明，AAP显著降低细胞的衰老程度并提高细胞活力，而Ex527阻断AAP的作用。同时，发现AAP增强细胞内SIRT1和CyclinD1的表达，降低p53的表达水平，在Ex527组中未观察到类似的逆转作用。线粒体分析结果显示，AAP可显著降低细胞内的活性氧水平，降低线粒体膜电位，减轻线粒体肿胀程度和增加线粒体内ATP含量，而Ex527的预处理消除这些作用。基于上述结果，推测AAP可能通过信号通路p53/p16和CyclinD/CDK4来改善线粒体功能，从而达到延缓衰老的作用，且这些作用与SIRT1密切相关。     

山豆根多糖对猪圆环病毒2型感染小鼠体内外炎性因子分泌水平的影响

旨在探究山豆根多糖对猪圆环病毒2型（porcine circovirus 2,PCV2）感染小鼠体内外炎性因子分泌水平的影响。通过PCV2感染小鼠脾淋巴细胞建立体外炎症模型,用不同浓度（100、200、400 μg/mL）的山豆根多糖作用细胞,采用ELISA法测定细胞分泌IL-1β、IL-8、MCP-1水平和细胞内COX-1活性;利用PCV2体内感染昆明种小鼠建立氧化胁迫模型后,腹腔注射低、中、高浓度[100、200、400 mg/（kg·BW）]的山豆根多糖,应用ELISA法测定小鼠脾脏、肺脏组织和血清中炎性因子IL-1β、IL-8、MCP-1分泌水平和COX-1活性。结果显示,与PCV2感染模型细胞相比,经不同浓度山豆根多糖处理的小鼠脾淋巴细胞中炎性因子IL-1β、IL-8、MCP-1水平和细胞内COX-1活性均不同程度降低,其中,400 μg/mL的山豆根多糖作用最佳（P<0.01）;利用不同浓度的山豆根多糖腹腔注射PCV2感染小鼠后,均能抑制PCV2感染小鼠的脾脏、肺脏组织和血清中炎性因子IL-1β、IL-8、MCP-1分泌水平和COX-1的活性,其中,高浓度[400 mg/（kg·BW）]的山豆根多糖作用最佳（P<0.01）。综上提示,山豆根多糖能够抑制PCV2感染小鼠炎性因子分泌,从而发挥抗炎作用。     

多糖的生物活性及其在蔬菜中的应用

为了聚焦作为植物诱抗剂、生长调节剂的多糖研究,并促进开发新型药剂及其在蔬菜中的应用,对多糖的种类、生物活性和机理及其在蔬菜应用中的进展进行综述,其中在蔬菜中,多糖主要用于病害防治、植株生长调节、贮藏保鲜等方面,未来应用领域将更加广阔。     

枸杞多糖的生理功能及其在动物生产中的应用

随着我国饲料“禁抗”时代的来临，天然的植物提取物逐渐成为一种新型替代抗生素的饲料添加剂。枸杞多糖是从枸杞及其副产物中提取出来的植物多糖类物质，主要由甘露糖、葡萄糖、半乳糖、阿拉伯糖、半乳糖醛酸和鼠李糖等组成，具有抗氧化、抗肿瘤以及提高机体免疫力等多种生理功能，是枸杞及其副产物的主要活性成分。本文综述了枸杞多糖的主要制备工艺、生理功能和作用机制及其在动物生产中应用的研究进展，旨在为枸杞多糖作为新型饲料添加剂在动物生产中的应用提供参考。     

Klebsiella pneumoniae capsular polysaccharide induces secretion of cytokines in bronchial epithelial cells via EGFR signaling pathway

AIM: To investigate the role of epidermal growth factor receptor (EGFR) in the secretion of inflammatory cytokines in human bronchial epithelial BEAS-2B cells induced by Klebsiella pneumoniae (KP) capsular polysaccharide (CPS). METHODS: KP was cultured in vitro, and the CPS was extracted. The BEAS-2B cells were stimulated with CPS at different concentrations, and the levels of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in the supernatant were measured by ELISA. The phosphorylation level of EGFR was detected by Western blot at different time points after stimulation. After pretreatment of the BEAS-2B cells with EGFR inhibitor AG1478, the phosphorylation level of ERK was detected by Western blot, the nuclear translocation of P65 was detected by indirect immunofluorescence, and the levels of TNF-α and IL-8 in the supernatant of the cells were measured. Finally, the levels of TNF-α and IL-8 in the culture supernatant of CPS-stimulated cells were detected by ELISA after pretreated with ERK inhibitor PD98059 and NF-κB inhibitor PDTC. RESULTS: Exposure to CPS at 10 mg/L for 12 h significantly induced the BEAS-2B cells to secret TNF-α and IL-8. The phosphorylation levels of EGFR and ERK and the nuclear translocation of p65 in the BEAS-2B cells were significantly increased after CPS stimulation (P<0.05). The phosphorylation level of ERK and the nuclear translocation of p65 were significantly reduced in the cells pretreated with EGFR inhibitor AG1478. Furthermore, the levels of TNF-α and IL-8 in the supernatant were significantly decreased after pretreated with the inhibitors of EGFR, ERK and NF-κB. CONCLUSION: Klebsiella pneumonia capsular polysaccharide activates the ERK and NF-κB signaling pathways via EGFR, and then induced the secretion of inflammatory cytokines TNF-α and IL-8 in the bronchial epithelial cells, indicating that EGFR may be a key factor in the inflammatory response induced by KP infection.     

物理改性对甘薯皮膳食纤维含量、多糖组成及其结构的影响

为进一步探究物理改性对甘薯皮可溶性膳食纤维(SDF)含量、多糖主成分与形貌结构的影响,采用超声、亚临界水和微波改性处理甘薯皮膳食纤维,测定SDF和甘薯皮膳食纤维中性多糖和酸性多糖的含量,并使用透射电镜、傅里叶红外光谱和X-射线衍射对改性前后的甘薯皮膳食纤维进行结构分析。结果显示:亚临界水改性对甘薯皮SDF得率、总膳食纤维(TDF)得率和中性多糖占比的影响显著(P<0.05)。SDF得率和中性多糖占比与膳食纤维被破坏的程度有关。酸性多糖中,0.1、0.2、0.3、0.5 mol·L^-1 NaCl洗脱出的部分占比最高的是未改性样品,分别占8.48%、19.52%、28.44%和2.32%;0.4 mol·L^-1 NaCl洗脱出的部分占比最高的是亚临界水改性样品,为10.99%;0.6 mol·L^-1 NaCl洗脱出的部分占比最高的是超声改性样品,为38.74%。透射电镜观察发现,亚临界水改性对甘薯皮TDF形态结构影响最明显,其比表面积增加,呈现出更复杂的空间结构。红外光谱分析可知,改性后的膳食纤维仍具备多糖的官能团,物理改性前后均存在果胶的多聚半乳糖醛酸结构,且物理改性增加了膳食纤维中果胶的总含量。X-射线衍射结果可知,亚临界水改性和微波改性均将甘薯皮TDF的纤维素晶型由Ⅰ型转化为Ⅱ型,其中,亚临界水改性对晶型的破坏最为严重。计算结晶度后可知,亚临界水改性样品的结晶度(21.33%)分别低于未改性、超声改性和微波改性样品15.12、7.85和4.41百分点。