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Bio-inspired enantioselective full transamination using readily available cyclodextrin
No full textThe mimics of vitamin B-6-dependent enzymes that catalyzed an enantioselective full transamination in the pure aqueous phase have been realized for the first time through the establishment of a new "pyridoxal 5'-phosphate (PLP) catalyzed non-covalent cyclodextrin (CD)-keto acid inclusion complexes" system, and various optically active amino acids have been obtained
地榆皂苷Ⅱ抑制肿瘤细胞增殖和诱导其凋亡的作用
No full text目的检测地榆皂苷II对多种肿瘤细胞的体外增殖抑制作用,研究地榆皂苷II诱导肿瘤细胞凋亡的分子机制。方法采用SRB法检测地榆皂苷II对肿瘤细胞的体外增殖抑制,通过Western blot来研究地榆皂苷II对三大凋亡通路的影响。结果地榆皂苷Ⅱ可上调MDA-MB-231细胞中活性氧的水平,上调CHOP的表达,激活内质网应激途径;下调Bcl-2的表达,上调Bax的表达,激活线粒体凋亡途径;上调DR4、DR5的表达,激活TRAIL外源凋亡通路。结论地榆皂苷II通过激活三大细胞凋亡通路来抑制肿瘤细胞的增殖,促进肿瘤细胞的凋亡
知母皂苷Officinalisinin Ⅰ对心肌缺血的保护作用及其机制研究
No full text目的:研究知母皂苷OfficinalisininⅠ对心肌缺血损伤的保护作用,并进一步探讨其可能的作用机制。方法:大鼠随机分为空白对照、模型对照、知母皂苷600mg/kg、知母皂苷300mg/kg、知母皂苷150mg/kg与地奥心血康120mg/kg(阳性对照)共6组,异丙肾上腺素制备大鼠急性心肌缺血模型。除空白对照外,每日灌胃给药,治疗5天。观察各组心肌组织的病理学变化以及检测各组的血清中磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)、天冬氨酸氨基转移酶(AST)含量变化。检测心肌组织中谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、活性氧(ROS)、超氧化物歧化酶(SOD)、血红素加氧酶-1(HO-1)、p53、Bcl-2和Bax的活性。结果:病理检查可以看出,相比模型对照,知母皂苷600mg/kg组肌束排列较为整齐,肌纤维没有明显的肿胀、断裂;知母皂苷600mg/kg组CK、AST、LDH、MDA、Bax、p53、ROS含量或活性显著降低;GSH-Px、SOD、Bcl-2活性显著增加。结论:知母皂苷具有保护心肌缺血损伤的作用,其可能的作用机制与抗自由基、抑制细胞凋亡有关
羌活属植物在不同海拔引种的生态适宜性研究
No full text采用人工引种栽培方式研究不同海拔梯度下羌活与宽叶羌活的生长状况、地下生物量和有效成分含量的变化规律,筛选羌活属植物的最佳种植区域。结果表明:(1)从栽培植株成活率和生物量等指标来看,羌活的生态适应范围是2 600~4 100 m;宽叶羌活生态适应海拔高度是1 700~3 600 m。(2)从药用部位有效成分含量与总量来看,羌活有效成分含量与总量较高的海拔范围是2 600~3 600 m,而宽叶羌活有效成分含量与总量较高的海拔则是1 700~3 600 m。综上所述,羌活生态和品质亚最适宜范围为2 600~3 600 m;宽叶羌活对应区域较宽,为1 700~3 600 m。该结果将为羌活属植株的野生驯化与人工栽培提供科学依据
Changes in the Intestinal Microbiota of Gibel Carp (Carassius gibelio) Associated with Cyprinid herpesvirus 2 (CyHV-2) Infection
No full textGut microbiota are integral to the host, and have received increased attention in recent years. However, information regarding the intestinal microbiota of many aquaculture animals is insufficient; elucidating the dynamics of the intestinal microbiota can be beneficial for nutrition, immunity, and disease control. In this study, we used 16S rRNA sequencing to observe changes in the intestinal microbiota of gibel carp (Carassius auratus gibelio) associated with cyprinid herpesvirus 2 (CyHV-2) infection. Our results indicate that the diversity of the intestinal microbiota was strongly reduced, and the composition was dramatically altered following CyHV-2 infection. The most dominant species in healthy fish were Cetobacterium, Rhodobacter, and Crenothrix; meanwhile, Cetobacterium, Plesiomonas, Bacteroides, and Flavobacterium were the most abundant species in sick fish. Plesiomonas was highly abundant in infected samples, and could be used as a microbial biomarker for CyHV-2 infection. Chemical properties of the aquaculture water were significantly correlated with the microbial community structure; however, it is difficult to determine whether these changes are a cause or consequence of infection. However, it may be possible to use probiotics or prebiotics to restore the richness of the host intestinal microbiota in infected animals to maintain host health
An integrated aerobic-anaerobic strategy for performance enhancement of Pseudomonas aeruginosa-inoculated microbial fuel cell
No full textMicrobial fuel cell (MFC) is a promising device for energy generation and organic waste treatment simultaneously by electrochemically active bacteria (EAB). In this study, an integrated aerobic-anaerobic strategy was developed to improve the performance of P. aeruginosa-inoculated MFC. With an aerobic start-up and following an anaerobic discharge process, the current density of MFC reached a maximum of 99.80 mu A/cm(2), which was 91.6% higher than the MFC with conventional constant-anaerobic operation. Cyclic voltammetry and HPLC analysis showed that aerobic start-up significantly increased electron shuttle (pyocyanin) production (76% higher than the constant-anaerobic MFC). Additionally, enhanced anode biofilm formation was also observed in the integrated aerobic-anaerobic MFC. The increased pyocyanin production and biofilm formation promoted extracellular electron transfer from EAB to the anode and were the underlying mechanism for the MFC performance enhancement. This work demonstrated the integrated aerobic-anaerobic strategy would be a practical strategy to enhance the electricity generation of MFC. (C) 2017 Elsevier Ltd. All rights reserved
Atmospheric pollen dispersion from herbicide-resistant horseweed (Conyza canadensis L.)
No full textHorseweed (Conyza canadensis (L.) Cronq.) with evolved herbicide resistance has become an especially problematic weed in crop production across the USA and on four continents (North America, South America, Asia, and Europe). Spread of herbicide resistance can occur through pollen-mediated gene flow between resistant and susceptible horseweed populations. However, there are little knowledge, preventive guidelines, and mechanism modeling for pollen transport in this system. We need to better understand pollen dispersion and deposition in the context of atmospheric conditions, herbicide-resistant horseweed patch size, and buffer crop type, height, and field size. A mechanistic model is needed to account for these. A pollen dispersion and deposition model was calibrated and validated using 2013 experimental field data. The validated model was run for various combinations of atmospheric conditions, horseweed characteristics (source strength), and buffer species and size (pollen can be intercepted by crop plants). Large fields with crops with a high leaf area density and tall plants can effectively prevent pollen dispersion. The information will help provide guidelines for preventing herbicide resistance spread from herbicide-resistant weeds and genetically modified plants in general
Production of high-concentration n-caproic acid from lactate through fermentation using a newly isolated Ruminococcaceae bacterium CPB6
No full textBackground: n-Caproic acid (CA), as a medium-chain carboxylic acid, is a valuable chemical feedstock for various industrial applications. The fermentative production of CA from renewable carbon sources has attracted a lot of attentions. Lactate is a significant intermediate waste in the anaerobic breakdown of carbohydrates that comprise 18-70% of the chemical oxygen demand (COD) in municipal and some industrial wastewaters. Recently, researchers (including our own group) reported the CA production using lactate as electron donor with newly identified microbiome systems. However, within such processes, it was hard to determine whether the CA production was completed by a single strain or by the co-metabolism of different microorganisms. Results: Here, we report the CA production using lactate as electron donor using the strain CPB6, which we isolated from a microbiome for CA production as described previously. Strain CPB6 is affiliated with Clostridium cluster IV of the family of Ruminococcaceae based on 16S rRNA gene sequence analysis. The strain prefers acidic initial pH condition (pH 5.0-6.5), and the temperature ranging from 30 to 40 degrees C for CA production. In a fed-batch fermentation with non-sterilized lactate-containing organic wastewater as feedstock, strain CPB6 produced 16.6 g/L CA (from 45.1 g/L lactate) with a maximum productivity of 5.29 g/L/day. Enzyme assays with crude cell extract showed that CPB6 can metabolize acetate and butyryl-CoA to produce n-butyric acid, and acetate/n-butyrate and caproyl-CoA to produce CA, respectively. Conclusion: This study demonstrated that high concentration of CA production can be obtained by a newly isolated pure culture CPB6. This strain can be employed as a powerful workhorse for high-efficient CA recovery from lactate-containing waste streams. Our preliminary investigation suggested that the CA production from lactate in strain CPB6 might be via the chain elongation pathway of the reverse beta-oxidation; the detailed mechanism, however, warrants further investigation using various molecular microbiology techniques
Enzymatic cascades for the stereo-complementary epimerisation of in situ generated epoxy alcohols
No full textThe synthesis of optically pure secondary epoxy alcohols from racemic allylic alcohols using a single whole-cell biocatalyst of recombinant Escherichia coli coexpressing three oxidoreductases is described. The cascade involves the concurrent action of a styrene monooxygenase that catalyzes the formation of the chiral epoxy group, and two alcohol dehydrogenases that fulfil the epimerisation of the hydroxy group. Two sets of alcohol dehydrogenases were each applied to couple with styrene monooxygenase in order to realize the epimerisation in a stereo-complementary manner. Excellent enantio-and diastereoselectivities were achieved for most of the 12 substrates
Multi-Omics Analysis Reveals a Correlation between the Host Phylogeny, Gut Microbiota and Metabolite Profiles in Cyprinid Fishes
No full textGut microbiota play key roles in host nutrition and metabolism. However, little is known about the relationship between host genetics, gut microbiota and metabolic profiles. Here, we used high-throughput sequencing and gas chromatography/mass spectrometry approaches to characterize the microbiota composition and the metabolite profiles in the gut of five cyprinid fish species with three different feeding habits raised under identical husbandry conditions. Our results showed that host species and feeding habits significantly affect not only gut microbiota composition but also metabolite profiles (ANOSIM, p <= 0.05). Mantel test demonstrated that host phylogeny, gut microbiota, and metabolite profiles were significantly related to each other (p <= 0.05). Additionally, the carps with the same feeding habits had more similarity in gut microbiota composition and metabolite profiles. Various metabolites were correlated positively with bacterial taxa involved in food degradation. Our results shed new light on the microbiome and metabolite profiles in the gut content of cyprinid fishes, and highlighted the correlations between host genotype, fish gut microbiome and putative functions, and gut metabolite profiles