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An efficient direct competitive nano-ELISA for residual BSA determination in vaccines
No full textA simple, fast, and highly sensitive direct competitive enzyme-linked immunosorbent assay (ELISA) based on bovine serum albumin (BSA) antigen labeled amine-terminated silicon dioxide (SiO2-NH-BSA) nanoparticles was developed to determine residual BSA in vaccines. As nano-ELISA using nanomaterials with a very high surface-to-volume ratio has emerged as a promising strategy, SiO2-NH-BSA nanoparticles were prepared in this study by the coupling of BSA to SiO2 nanoparticles modified with amidogen, followed by the quantification of BSA via a direct competitive binding of BSA-antigen-labeled SiO2 nanoparticles to anti-BSA antibody conjugated with horseradish peroxidase. The validation study showed that the linear range of this method was from 1 to 90 ng/mL (r = 0.998) and the limit of detection was 0.67 ng/mL. The intra-assay and interassay coefficients of variation were less than 10% at three concentrations (10, 40, and 70 ng/mL), and the recovery was 92.4%, indicating good specificity. As a proof of principle, this new method was applied in the analysis of residual BSA in five different vaccines. Bland-Altman plots revealed that there was no significant difference in the accuracy and precision between our new method and the most commonly used sandwich ELISA. From the results taken together, the new method developed in this study is more sensitive and facile with lower cost and thus demonstrated potential to be applied in the quality control of biological products
Copper catalyzed one-pot synthesis of beta-ketophosphine oxides from ketones and H-phosphine oxides
No full textA facile and efficient copper catalyzed one-pot method has been developed for the formation of beta-ketophosphine oxides from ketones and H-phosphine oxides under air at room temperature, in which vinylhydrazinedicarboxylate was formed as the key intermediate. Preliminary mechanistic studies indicated that the reaction might involve a radical process and carbonyl oxygen atom of beta-ketophosphine oxides came from molecular oxygen. (C) 2017 Elsevier Ltd. All rights reserved
Saponins from Sanguisorba officinalis Improve Hematopoiesis by Promoting Survival through FAK and Erk1/2 Activation and Modulating Cytokine Production in Bone Marrow
No full textRadix Sanguisorbae, the root of Sanguisorba officinalis L. is used as traditional Chinese medicine. In recent decades, it has been reported to be clinically effective against myelosuppression induced by chemotherapy and/or radiotherapy. However, the underlining mechanism has not been well studied. In this work, we evaluated the hematopoietic effect of total saponins from S. officinalis L. on myelosuppressive mice induced by cyclophosphamide and by(60)Co-gamma-irradiation and confirmed the therapeutic effect. Then, we found total saponins and their characteristic constituents Ziyuglycoside I and Ziyuglycoside II can inhibit apoptosis of TF-1 cells caused by cytokine deprivation, and promote survival of mouse bone marrow nuclear cells through focal adhesion kinase (FAK) and extracellular signal-regulated kinase 1/2 (Erk1/2) activation in vitro. In addition, they can down-regulate macrophage inflammatory protein 2 (MIP-2), platelet factor 4 (PF4) and P-selectin secretion, which are reported to be suppressive to hematopoiesis, both in vitro and in vivo. These results suggest that promotion of survival through FAK and Erk1/2 activation and inhibition of suppressive cytokines in the bone marrow is likely to be the pharmacological mechanism underlying the hematopoietic effect of saponins from S. officinalis L
Characterization of major metabolites of polymethoxylated flavonoids in Pericarpium Citri Reticulatae using liver microsomes immobilized on magnetic nanoparticles coupled with UPLC/MS-MS
No full textThe peels of citrus fruits (Pericarpium Citri Reticulatae, PCR) have long been used in traditional Chinese medicines (TCMs). Polymethoxylated flavonoids (PMFs) were found to be the main components present in PCR extracts, but their metabolism remains unclear which restrain the utilization of this TCM. In the present work, rat liver microsomes were immobilized on magnetic nanoparticles (LMMNPs) for in vitro metabolic study on the whole PMFs of PCR. LMMNPs were characterized by transmission electron microscope and Fourier-transform infrared spectrum. The relative enzyme binding capacity of LMMNPs was estimated to be about 428 mu g/mg from thermogravimetric analysis. Incubation of LMMNPs with PMFs produced demethylated metabolites of PMFs, six of which were identified by ultra-high pressure liquid chromatography-mass spectrometry (UPLC-MS/MS). The 3'-hydroxylated tangeretin (T3) was detected from the metabolites of tangeretin for the first time, which suggested that 4'-demethylated and 3'-hydroxylated derivative of tangeretin (3'-hydroxy-5,6,7,8,4'-pentamethoxyflavone, T4) was not only derived from 4'-demethylated tangeretin (T2) as previously reported, but also from T3. This is the first investigation of the metabolism of the whole PMFs, which may shed light on the mechanism of action of PCR
The responses and adaptations of microbial communities to salinity in farmland soils: A molecular ecological network analysis
No full textSoil salinity is an increasing problem deteriorating soil fertility in degraded farmland soils. However, the responses and adaptations of microbial communities and interactions to salinity in farmland are not yet fully understood. In this study, we used 16S rRNA Miseq-sequencing technique to investigate the phylogenetic compositions, diversity and structure of soil microbial communities under different salinity conditions. The results indicated that prokaryotic diversity decreased with salinity. The change in prokaryotic community was primarily driven by salinity levels. The relative abundances of Proteobacteria, Bacteroidetes and Firmicutes were higher, and those of Acidobacteria and Thaumarchaeota were lower under high salinity than in medium and low salinity soils. Further, microbial network interactions changed along the salinity gradient revealed by a phylogenetic molecular ecological networks (pMENs) analysis. Salinity enhanced the interactions between microorganisms, evidenced by more links, higher average degree and average clustering coefficients within the pMENs in high salinity soils. Furthermore, we constructed the sub-networks of Flavobacterium and Acidobacteria_Gp4 to explore the changes of interactions among different microbial groups under salinity. We found that salinity shifted the interactions among different microbial taxa, and such changes vary among different microbial populations. This study provides solid evidences that microbial communities adapt to salinity through the adjustments of microbial compositions and interactions
The diversity and co-occurrence patterns of diazotrophs in the steppes of Inner Mongolia
No full textSoil diazotrophs possess the function of fixing atmospheric NZ into biologically available ammonium in terrestrial ecosystems. However, there are limited studies into how diazotrophic communities change when grassland environments differ. In this study, we elucidated the diversity and interactions of diazotrophic communities in three steppe types of Inner Mongolia, China, including non-desert steppe (MT), desert steppe (D) and sandy steppe (S). We expected to improve the predictions of diazotrophic responses to grassland degradation at time gradients based on their discrepancies among steppe types along spatial gradients. Steppe types affected the alpha- and beta-diversity of diazotrophic communities, which were mainly controlled by plant biomass and soil pH, respectively. Diazotrophic communities were strongly aggregated with their respective steppe environments, but dissimilar under different types according to Bray-Curtis distance. In addition, network analysis showed that the network structure of diazotrophs from the D was relatively simpler than the other two types (MT and S). More exclusionary relationships in diazotrophic communities occurred in the D and S steppes than in the MT steppe. The species shared across the steppes changed their interactions with other species to adapt to different habitats. Moreover, different steppes had distinct key species to underpin the whole network. The disturbances or extinctions of these key species may lead to the instability of the diazotrophic co-occurrence network. Overall, we speculate that if grassland degradation happens, the change of grassland microenvironment may mediate the differences in the diversity and co-occurrence patterns of diazotrophs, allowing them to adapt to environmental changes
Fungal community and cellulose-degrading genes in the composting process of Chinese medicinal herbal residues
No full textThe fungal community and the population of 16S rRNA, 18S rRNA and cellulose-degrading genes during the 30-day composting process of Chinese medicinal herbal residues were investigated using Illumina MiSeq and quantitative real-time PCR. An obvious succession of fungal communities occurred during the composting process. Unidentified fungi predominated in the raw materials. As composting progressed, Ascomycota became the most dominant phylum, with Aspergillus being the most dominant genus, and Aspergillus fumigatus making up 99.65% of that genus. Because of the inoculation of cellulolytic fungi in the mature stage, the cellulose degradation rate in inoculation groups was faster and the relative abundances of Aspergillus and the glycoside hydrolase family 7 genes were significantly higher than those in the control groups. These indicated that the fungal inoculants facilitated the degradation of cellulose, increased cellulolytic fungi and optimized the community structure. (C) 2017 Published by Elsevier Ltd
一株高效生物絮凝剂产生菌B17的培养优化
No full text从活性污泥中筛选得到的一株高活性的生物絮凝剂产生菌B17,采用单因素实验优化培养时间、碳源、氮源、碳氮比、初始pH值、接种量等培养条件,选择乳糖作为碳源,乙酸铵为氮源,碳氮比为20:1,发酵初始pH值为6.0-7.0,接种量为3%,在此最优组合的发酵条件下以温度30℃振速160rpm培养24h,絮凝活性可提高25%-38.3%
生物硫铁复合材料对Cr(VI)污染水体中斑马鱼的保护作用
No full text目前铬污染已经成为世界性的环境问题.为探究生物硫铁复合材料(生物硫铁,BISC)在Cr~(6+)污染水体中对鱼类的保护作用,以斑马鱼为实验载体,在测定Cr~(6+)对斑马鱼的半数致死浓度(LC50)的基础上,研究生物硫铁对Cr~(6+)污染水体的处理效果,以及生物硫铁投加比(生物硫铁与Cr~(6+)的摩尔浓度之比)、投加时间和水体p H对Cr~(6+)污染水体中斑马鱼保护作用的影响.结果显示,在79.30 mg/L(24 h-LC50)Cr~(6+)污染水体(p H=6.98)中,生物硫铁的投加能够快速降低水体Cr~(6+)的浓度.当生物硫铁投加比达到3时能将Cr~(6+)快速去除,15 min后Cr~(6+)去除率达到84.01%,96 h后达到99.99%.斑马鱼存活率随生物硫铁投加比的增加和投加时间的减少而增大,最佳投加比为0.5;最佳投加时间为0-4 h,此时能将斑马鱼存活率提高90%以上,24 h时投加,作用96 h后亦可使斑马鱼存活率提高约3倍.在p H 6-9内,生物硫铁的投加可显著提高斑马鱼的存活率,且对斑马鱼的保护作用随p H降低而逐渐增强.本研究表明生物硫铁对Cr~(6+)污染水体中的斑马鱼保护效果显著,在Cr~(6+)突发污染治理方面具有广阔的应用前景
贡嘎山海拔梯度上不同植被类型土壤甲烷氧化菌群落结构及多样性
No full text甲烷是仅次于CO_2的第二大温室气体.森林表层土壤中甲烷好氧氧化作用是大气甲烷重要的汇,在碳循环和减缓全球变暖方面起着重要作用.研究不同植被类型土壤中甲烷氧化菌的群落结构及多样性,有助于更好地理解植被演替、人为干扰和不同土地利用背景下甲烷氧化菌群落组成和多样性变化与地上植被之间的相互关系.本研究在贡嘎山东坡海拔梯度上的4种不同植被类型中采集了92个土壤样品,利用Miseq测序技术和生物信息学方法评估了甲烷氧化菌群落组成及多样性在4种不同植被类型间的变化,并探讨了其变异的潜在原因.结果表明:常绿阔叶林和针阔叶混交林土壤中甲烷氧化菌的群落结构较为相似,暗针叶林和灌丛草甸土壤甲烷氧化菌的群落结构较为相似.4种不同植被生态系统中,针阔叶混交林土壤中的甲烷氧化菌α多样性显著高于其他3种植被生态系统(P<0.001),且暗针叶林和灌丛草甸土壤中甲烷氧化菌β多样性显著高于常绿阔叶林和针阔叶混交林(P<0.001).Spearman相关分析表明,不同类型甲烷氧化菌的相对丰度对环境变化的响应模式不同.造成α多样性差异的主要因子可能是土壤总氮、电导率和土壤温度.偏Mantel检验分析和冗余分析(RDA)表明,常绿阔叶林和针阔叶混交林土壤甲烷氧化菌多样性受环境因子的影响较大,而暗针叶林和灌丛草甸土壤中甲烷氧化细菌多样性变化可能存在其他潜在的影响因素或者机制.降水可能是造成低海拔常绿阔叶林和针阔叶混交林与高海拔暗针叶林和灌丛草甸土壤甲烷氧化细菌群落结构差异的主要原因.贡嘎山海拔梯度上不同植被类型土壤中甲烷氧化菌的群落结构和多样性变化可能主要是由于土壤理化性质和气候变化综合作用的结果