Effect of dextransucrase cellobiose acceptor products on the growth of human gut bacteria     

Ruiz-Matute AI  Brokl M  Sanz ML  Soria AC  Côté GL  Collins ME  Rastall RA 《Journal of agricultural and food chemistry》2011,59(8):3693-3700

The selective fermentation by human gut bacteria of gluco-oligosaccharides obtained from the reaction between the glucosyl group of sucrose and cellobiose, catalyzed by dextransucrases (DSR) from Leuconostoc mesenteroides , has been evaluated. Oligosaccharides were fractionated according to their molecular weight, and their effect on the growth of different bacterial groups was studied. To determine the structure (position and configuration of glycosidic linkages)-function relationship, their properties were compared to those of DSR maltose acceptor products (DSRMal) and of recognized prebiotic carbohydrates (fructo-oligosaccharides, FOS). Cellobiose acceptor products (DSRCel) showed bifidogenic properties similar to those of FOS. However, no significant differences related to molecular weight or isomeric configurations were found for DSRCel and DSRMal products.  相似文献   

th modern manage     

ment t 《农村新技术》2005,(7)

rward some suggestions for the improvement of modern business administration at the same time.four great classical masterpieces; trditional culture; business management; vision; lead; ta  相似文献   

Influence of glycosidic linkages and molecular weight on the fermentation of maltose-based oligosaccharides by human gut bacteria     

Sanz ML  Côté GL  Gibson GR  Rastall RA 《Journal of agricultural and food chemistry》2006,54(26):9779-9784

A structure-function study was carried out to increase knowledge of how glycosidic linkages and molecular weights of carbohydrates contribute toward the selectivity of fermentation by gut bacteria. Oligosaccharides with maltose as the common carbohydrate source were used. Potentially prebiotic alternansucrase and dextransucrase maltose acceptor products were synthesized and separated into different molecular weights using a Bio-gel P2 column. These fractions were characterized by matrix-assisted laser desorption/ionization time-of-flight. Nonprebiotic maltooligosaccharides with degrees of polymerization (DP) from three to seven were commercially obtained for comparison. Growth selectivity of fecal bacteria on these oligosaccharides was studied using an anaerobic in vitro fermentation method. In general, carbohydrates of DP3 showed the highest selectivity towards bifidobacteria; however, oligosaccharides with a higher molecular weight (DP6-DP7) also resulted in a selective fermentation. Oligosaccharides with DPs above seven did not promote the growth of "beneficial" bacteria. The knowledge of how specific structures modify the gut microflora could help to find new prebiotic oligosaccharides.  相似文献   

Risk factors associated with transmission of Mycobacterium avium subsp. paratuberculosis to calves within dairy herd: a systematic review     

Doré E  Paré J  Côté G  Buczinski S  Labrecque O  Roy JP  Fecteau G 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2012,26(1):32-45

  相似文献   

马立克氏病的演变全景     

Ｒ．Ｌ．Ｗｉtｔｅｒ  李永清  张原 《中国畜牧兽医》1999,(2)

马立克氏病（ＭＤ）是一类由细胞结合性疱疹病毒引起的家禽疾病,该病首次报道于１９０７年,科学工作者已经对该病及病毒进行广泛的研究和探讨。马立克氏病病毒（ＭＤＶ）在血清学可分为：对鸡致病的１型以及另外两组从鸡和火鸡的自然病例中分离到的非致瘤性的疱疹病毒,...  相似文献   

Studies on the inactivation of selected viral and bacterial fish pathogens at high pH for waste disposal purposes     

Dixon PF  Algoët M  Bayley A  Dodge M  Joiner C  Roberts E 《Journal of fish diseases》2012,35(1):65-72

This study investigated the use of alkaline hydrolysis at ambient temperature for inactivation of selected fish pathogens in fish tissues under conditions approximating those that are likely to be found in the aquaculture industry. Infectious salmon anaemia virus (ISAV) and Lactococcus garvieae have been determined in a previous study to be the most resistant virus and bacteria to pH 12 from a wide range of viruses and bacteria tested. They were spiked at high titres into fish extracts that were then treated with 1 m sodium hydroxide (NaOH). Viable L. garvieae was not detected in the treated fish extract after 1 h, and ISAV was not detected after 24‐h exposure. Field mortalities of Atlantic salmon, Salmo salar L., caused by infectious pancreatic necrosis virus were treated by alkaline hydrolysis at ambient temperature. The macerated fish mortalities contained a high titre of virus (3.38 × 10⁸ TCID₅₀ g^?1) that was reduced to approximately 2.2 × 10³ TCID₅₀ g^?1 after 24‐h exposure to NaOH, and virus was not detected after exposure for 48 h. The results suggest that alkaline hydrolysis at ambient temperature has potential as a biosecure treatment method for fish by‐products containing fish pathogens.  相似文献   

In vitro fermentation of alternansucrase raffinose-derived oligosaccharides by human gut bacteria     

Hernandez-Hernandez O  Côté GL  Kolida S  Rastall RA  Sanz ML 《Journal of agricultural and food chemistry》2011,59(20):10901-10906

In this work, in vitro fermentation of alternansucrase raffinose-derived oligosaccharides, previously fractionated according to their degree of polymerization (DP; from DP4 to DP10), was carried out using small-scale pH-controlled batch cultures at 37 °C under anaerobic conditions with human feces. Bifidogenic activity of oligosaccharides with DP4-6 similar to that of lactulose was observed; however, in general, a significant growth of lactic acid bacteria Bacteroides , Atopobium cluster, and Clostridium histolyticum group was not shown during incubation. Acetic acid was the main short chain fatty acid (SCFA) produced during the fermentation process; the highest levels of this acid were shown by alternansucrase raffinose acceptor pentasaccharides at 10 h (63.11 mM) and heptasaccharides at 24 h (54.71 mM). No significant differences between the gas volume produced by the mixture of raffinose-based oligosaccharides (DP5-DP10) and inulin after 24 h of incubation were detected, whereas lower gas volume was generated by DP4 oligosaccharides. These findings indicate that novel raffinose-derived oligosaccharides (DP4-DP10) could be a new source of prebiotic carbohydrates.  相似文献   

混凝土面板堆石坝反分析的神经网     

夏富洲  汤电波  王长德t s 《中国农村水利水电》2008,(7):64-67

建立了坝体沉降变形分解的统一模型,采用最小二乘法进行多元线性回归分析,将面板堆石坝坝体沉降变形的实测值分解为荷载作用变形与蠕变作用变形。运用MATLAB语言提供的神经网络功能函数,建立面板堆石坝反分析的BP神经网络模型,对邓肯E-B模型的材料参数进行反演计算。实例计算结果表明,方法简单、有效、可靠,计算结果满足工程精度要求,可应用于实际工程。  相似文献   

泄洪道底孔弧形闸门检测及其加固     

陈焰周  刘嘉慧  郭耀杰t s 《中国农村水利水电》2008,(5):80-82

以某水力发电厂的泄洪道底孔弧形闸门的检测为例,阐述重要闸门检测的内容、方法,包括闸门的巡视检查、外观及腐蚀状况检测、材质检测、焊缝超声波无损探伤、启闭机性能检测、结构应力测试以及结构静力分析计算,并对该弧形闸门存在的问题,提出了相应加固方案。对类似的水工金属结构检测工程有一定的借鉴作用。  相似文献   

物元分析在区域雨水资源开发利用   总被引：1，自引：0，他引：1  

张丽  彭小金  周丰t s 《中国农村水利水电》2008,(6):46-48

根据物元分析理论,建立了区域雨水资源开发利用评价模型,即将区域雨水资源开发利用阶段各特征值及相应标准作为经典物元,待评价区域雨水资源开发利用特征值作为待评物元,由关联函数计算待评物元特征指标与经典物元特征指标的关联度,加权求和得出待评物元关于各等级的综合关联度,进而分析雨水资源开发利用所属阶段。研究表明,物元分析理论概念清晰,原理完善,计算简单,可推广应用于水资源及雨水资源开发利用潜力评价,同时也值得在水资源评价领域推广。  相似文献