Effects of Different Sources and Levels of Copper on Growth Performance,Nutrient Digestibility,and Elemental Balance in Young Female Mink (Mustela vison)

An experiment was conducted in a 3?×?3?+?1 factorial experiment based on a completely randomized design to evaluate the effects of different sources of copper on growth performance, nutrient digestibility and elemental balance in young female mink on a corn–fishmeal-based diet. Animals in the control group were fed a basal diet (containing 8.05 mg Cu/kg DM; control), which mainly consisted of corn, fish meal, meat bone meal, and soybean oil, with no copper supplementation. Minks in other nine treatments were fed basal diets supplemented with Cu from reagent-grade copper sulfate, tribasic copper chloride (TBCC) and copper methionate. Cu concentrations of experiment diets were 10, 25, and 40 mg/kg copper. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Final body weight and average daily gain increased (linear and quadratic, P?<?0.05) as Cu increased in the diet; maximal growth was seen in the Cu25 group. Cu supplementation slightly improved the feed conversion rate (P?=?0.095). Apparent fat digestibility was increased by copper level (P?=?0.020). Retention nitrogen was increased by copper level (linear, P?=?0.003). Copper source had a significant effect on copper retention with Cu-Met and copper sulfate treatments retention more than TBCC treatments (P?<?0.05). Our results indicate that mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in mink, and mink can efficiently utilize Cu-Met and CuSO₄.     

蛇足石杉内生真菌Shiraia sp. Slf14中赖氨酸脱羧酶基因的克隆、表达及功能

【目的】阿尔茨海默症治疗药物石杉碱甲(Huperzine A,Hup A)的生物合成途径起始于赖氨酸脱羧酶(Lysine decarboxylase,LDC)。本研究克隆及表达了来源于产Hup A的植物内生真菌的LDC基因,并研究了其功能。【方法】采用RT-PCR扩增法,从一株产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14获得LDC基因,构建表达质粒p ET-22b-LDC与p ET-32a-LDC,转化感受态细胞E.coli BL21,加入IPTG至终浓度为1×10~(–3) mol/L,于24°C、200 r/min培养8 h,诱导表达LDC蛋白质;通过Ni~(2+)金属亲和层析纯化重组LDC并建立酶促反应体系,利用TLC检测了LDC催化活性。利用生物信息学软件分析了LDC的理化性质及蛋白质的空间结构。【结果】成功克隆并异源表达出重组蛋白LDC与Trx-LDC,经SDS-PAGE电泳鉴定分子量分别为24.4 k Da和42.7 k Da,与预计大小相符。TLC结果表明LDC与Trx-LDC均具有赖氨酸脱羧酶活性。【结论】本研究从产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14中成功克隆到LDC基因并进行了异源表达,检测到了其催化活性,为丰富LDC分子信息及阐明内生真菌中Hup A生物合成机制提供参考数据。     

酿酒酵母产苹果酸的还原TCA路径构建及发酵调控

苹果酸广泛应用于食品、化工行业。文中通过在酿酒酵母内敲除丙酮酸脱羧酶PDC1,并通过构建胞质内还原TCA的路径,即超表达丙酮酸羧化酶和苹果酸脱氢酶,成功地实现了苹果酸的生产。在野生型菌株中基本检测不到苹果酸的生成,而在工程菌株,苹果酸发酵浓度达到了45 mmol /L,同时副产物乙醇的产量也降低了18%。进一步通过发酵调控提高第二信使Ca2+的浓度使苹果酸的产量提高了7 %,在此基础上提高丙酮酸羧化酶的辅酶生物素浓度,使苹果酸的产量达到52.5 mmol /L,较原始菌株提高了16%。     

Highly Heterogeneous Bacterial Communities Associated with the South China Sea Reef Corals Porites lutea,Galaxea fascicularis and Acropora millepora

Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.     

The primary structure of human apolipoprotein A-IV

Human apolipoprotein (apo) A-IV was purified from chylous ascites fluid. Proteolytic peptides produced by trypsin and Staphylococcus aureus V8 proteinase digestions were purified by high-performance liquid chromatography and sequenced. Human apoA-IV contains 376 amino acid residues. The peptide-derived sequence generally matches two previously reported DNA-derived amino acid sequences except for discrepancies in five positions. In order to examine these discrepancies further, one complete apoA-IV cDNA clone and another partial clone were sequenced. Comparison of all the available information indicates that the peptide-derived sequence reported here is accurate. Sequencing errors probably account for some of the discrepancies between the two primary sequences predicted by earlier nucleotide analyses. In certain positions, however, bona fide sequence heterogeneity or cloning artifact cannot be excluded.     

玫瑰微球菌中treZ基因在毕赤酵母中的表达研究

首次将玫瑰微球菌中麦芽寡糖基海藻糖水解酶(MTHase)treZ基因序列连接到表达载体pPICZαA中,通过电转化法将构建好的表达载体分别转入巴斯德毕赤酵母GS115和KM71菌株中.利用含有Zeocin的YPD平板筛选到阳性转化子,并经PCR、SDS-PAGE电泳以及Western blot最终验证海藻糖水解酶基因treZ已经整合到巴斯德毕赤酵母的基因组上,并且得到了预期的表达.     

Comprehensive gene and microRNA expression profiling reveals the crucial role of hsa-let-7i and its target genes in colorectal cancer metastasis

Accumulating evidence has demonstrated that miRNAs play important roles in the occurrence and development of colorectal cancer (CRC). However, whether miRNAs are associated with the metastasis of CRC remains largely unexplored. The aim of the current study is to profile miRNAs in different CRC metastatic cell lines to identify the biomarkers in CRC metastasis. Gene and miRNA expression profiling was performed to analyze the global expression of mRNAs and miRNAs in the four human CRC cell lines (LoVo, SW480, HT29 and Caco-2) with different potential of metastasis. Expression patterns of mRNAs and miRNAs were altered in different CRC cell lines. By developing an integrated bioinformatics analysis of gene and miRNA expression patterns, hsa-let-7i was identified to show the highest degree in the microRNA-GO-network and microRNA-Gene-network. The expression level of hsa-let-7i was further validated by qRT-PCR in CRC cells. In addition, the targets of hsa-let-7i were predicted by two programs TargetScan and PicTar, and target genes were validated by expression profiling in the most epresentative LoVo and Caco-2 cell lines. Eight genes including TRIM41, SOX13, SLC25A4, SEMA4F, RPUSD2, PLEKHG6, CCND2, and BTBD3 were identified as hsa-let-7i targets. Our data showed the power of comprehensive gene and miRNA expression profiling and the application of bioinformatics tools in the identification of novel biomarkers in CRC metastasis.     

甲状腺功能减退孕妇糖代谢、肾功能指标的变化及临床意义

目的:探究妊娠期甲状腺功能减退患者糖代谢及肾功能变化及临床意义。方法:选择2015年6月至2019年8月来我院就诊的甲状腺功能减退孕妇60例作为甲减组及同期健康孕妇60例作为对照组。比较两组患者甲状腺功能[促甲状腺激素(TSH)、游离三碘甲状腺原氨酸(FT_3)及游离甲状腺素(FT_4)]、糖代谢指标[空腹血糖水平(FBG)、糖化血红蛋白(HbA1C)、餐后2 h抽取肘静脉血测定餐后2 h葡萄糖水平(2hPG)、胰岛素抵抗指标(HOMA-IR)]及肾功能[血清肌酐(Cr)、血清尿酸(UA)、血尿素氮(BUN)],分析甲状腺功能与糖代谢及肾功能的关系,比较两组患者的妊娠结局。结果:甲减组孕妇的TSH、糖代谢、肾功能各指标水平较对照组显著升高,FT_4较对照组明显降低(P0.05)。TSH与糖代谢各指标均呈正相关(P0.05);FT_4与糖代谢各指标均呈负相关(P0.05),FT_3与Cr呈负相关(P0.05),TSH、FT_4与Cr、UA、BUN均无明显相关性(P0.05)。甲减组的不良妊娠结局率为20.00%,显著高于对照组(6.67%,P0.05)。结论:妊娠期甲状腺功能减退患者存在糖代谢紊乱、肾功能异常,可能导致不良妊娠结局。