超声诊断原发性肝癌的研究

本文33例原发性肝癌的超声诊断研究中24例有1.5至30年的肝病史。最近一次确诊为肝硬化者或无肿瘤者到首次发现肿瘤的时间为3至98天,平均27.3天,其中一例仅隔3天再查就发现肝左叶有多发性低回声肿瘤,最大肿瘤为64×65mm;首次发现肿瘤到第二次复查的时间为15至158天,平均49.4天,肿瘤平均增大约1.5倍,从单个发展至多个。本文就上述原发性肝癌发展的超声诊断跟踪分析探讨。     

急性心肌梗死患者肠道优势菌群分析

目的探讨急性心肌梗死患者肠道优势菌群的改变及其与疾病严重程度的关系。方法共筛选急性心肌梗死患者71名及正常健康体检者33名,急性心肌梗死患者根据是否心衰分为急性心肌梗死组36名和急性心肌梗死伴泵衰竭组35名,所有入选者收集大便及血清标本,分别采用qPCR及化学发光仪测定肠道优势菌群改变和血清脑钠肽前体及肌钙蛋白水平。结果急性心肌梗死患者肠道优势菌群显著改变,肠道肠杆菌以及肠球菌细菌数量较对照组显著增加,均与脑钠肽前体、肌钙蛋白、Killip分级显著正相关,而双歧杆菌、乳酸杆菌等细菌数量显著降低,与脑钠肽前体、肌钙蛋白、Killip分级显著负相关。结论急性心肌梗死患者呈现典型的肠道菌群紊乱,且与患者疾病严重程度相关。     

随机SNP在全基因组关联研究人群分层分析中的应用

在复杂疾病的全基因组关联研究中,人群分层现象会增加结果的假阳性率,因此考虑人群遗传结构、控制人群分层是很有必要的。而在人群分层研究中,使用随机选择的SNP的效果还有待进一步探讨。文章利用HapMap Phase2人群中无关个体的Affymetrix SNP 6.0芯片分型数据,在全基因组上随机均匀选择不同数量的SNP,同时利用f值和Fisher精确检验方法筛选祖先信息标记（Ancestry Informative Markers,AIMs）。然后利用HapMap Phase3中的无关个体的数据,以F-statistics和STRUCTURE分析两种方法评估所选出的不同SNP组合对人群的区分效果。研究发现,随机均匀分布于全基因组的SNP可用于识别人群内部存在的遗传结构。文章进一步提示,在全基因组关联研究中,当没有针对特定人群的AIMs时,可在全基因组上随机选择3000以上均匀分布的SNP来控制人群分层。     

Assessment of Real-time PCR Based Methods for Quantification of Pollen-mediated Gene Flow from GM to Conventional Maize in a Field Study

Maize is one of the main crops worldwide and an increasing number of genetically modified (GM) maize varieties are cultivated and commercialized in many countries in parallel to conventional crops. Given the labeling rules established e.g. in the European Union and the necessary coexistence between GM and non-GM crops, it is important to determine the extent of pollen dissemination from transgenic maize to other cultivars under field conditions. The most widely used methods for quantitative detection of GMO are based on real-time PCR, which implies the results are expressed in genome percentages (in contrast to seed or grain percentages). Our objective was to assess the accuracy of real-time PCR based assays to accurately quantify the contents of transgenic grains in non-GM fields in comparison with the real cross-fertilization rate as determined by phenotypical analysis. We performed this study in a region where both GM and conventional maize are normally cultivated and used the predominant transgenic maize Mon810 in combination with a conventional maize variety which displays the characteristic of white grains (therefore allowing cross-pollination quantification as percentage of yellow grains). Our results indicated an excellent correlation between real-time PCR results and number of cross-fertilized grains at Mon810 levels of 0.1–10%. In contrast, Mon810 percentage estimated by weight of grains produced less accurate results. Finally, we present and discuss the pattern of pollen-mediated gene flow from GM to conventional maize in an example case under field conditions.     

Assessment of the effect of triton X‐114 on the physicochemical properties of an antibody fragment

The effect of Triton X‐114 on the physicochemical properties of a single‐chain antibody fragment (scFv) has been studied. According to the far UV circular dichroism spectroscopy, the secondary structure of the recombinant antibody was not significantly affected by the presence of Triton. From the antibody tertiary structure analysis, it was found that the surfactant could be located around the tryptophan molecules accessible to the solvent, diminishing the polarity of its environment but maintaining most of the protein structure integrity. However, in certain conditions of high temperature and high concentration of denaturant molecules, the presence of TX could compromise the antibody fragment stability. These results represent a previous step in designing scFv purification protocols and should be considered prior to developing scFv liquid–liquid extraction procedures. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:554–561, 2014     

豚鼠心脏CDP-乙醇胺磷酸转移酶的动力学研究

为探讨不同的二价基甘油对三种乙醇胺甘油磷脂生物合成能力的影响,通过对豚鼠乙醇胺磷酸转移酶动力学研究,发现磷脂酰乙醇胺的合成可被1-烷基-2-脂酰甘油和1-烯醚基-2-脂酰甘油抑制,而缩醛磷脂酰乙醇胺的生成不受1,2-二脂酰甘油影响,并提示不同的二价基甘油对乙醇胺磷酸转移酶的抑制作用呈非竞争性抑制,此有利于对三种乙醇胺磷脂酰甘油生物合成的相互协调作用。     

双歧杆菌对新生大鼠坏死性小肠结肠炎肠损伤及肠道菌群影响

目的建立新生SD大鼠坏死性小肠结肠炎（NEC）模型,探讨添加双歧杆菌对新生大鼠NEC模型肠损伤的保护作用及肠道菌群的影响,为应用双歧杆菌防治NEC提供依据：方法SD新生大鼠出生48h开始给予鼠配方奶人工喂养,100％氮气缺氧90s,4℃冷刺激10min,每天2次,连续3d,建立新生SD大鼠NEC模型。按析因设计,32只新生SD大鼠随机分成4组,每组动物各8只。A组为NEC模型组并在出生48h起每日给予长双歧杆菌灌胃（1×10^8CFU／d）;B组为NEC模型组,C组为对照组,都未添加双歧杆菌;D组为对照组并给予长双歧杆菌灌胃（1×10^8CFU／d）。在最后一次缺氧、冷刺激后24h空腹断头处死大鼠,留取回盲部近端肠管组织进行肠组织损伤评分,组织学评分≥2确定为NEC;实验前后留取各组新生鼠粪便,按照张秀荣方法进行肠道菌群检测。应用Kruskal-Wallis H检验等方法进行统计学分析,α=0．05为显著性检验标准。结果开始造模后,A、B组新生SD大鼠相继出现腹泻、腹胀、萎靡、活动减少,A组程度较轻。A、B、C和D组肠组织损伤评分（^-x±s）分别为1．88±0.84、3．13±0．84、0．63±0．52、0．50±0.54,各组间肠组织损伤评分差异有显著性,与B组相比,A组肠组织损伤评分明显降低,但仍高于C、D两组,差异均有显著性。各组实验前肠道细菌总数,杆菌、球菌数,G^＋杆菌、G^＋球菌数差异均无显著性,肠道菌群中杆球菌比值在正常范围中。实验结束时,各组间新生鼠肠道细菌总数,杆菌、球菌数,杆球菌比值,G^＋杆菌、G^＋球菌数及其占肠道总菌群数的比率差异均有显著性;除B组杆菌数外,与实验前相比,各组新生大鼠实验结束后肠道细菌总数、球菌数、杆菌数、G^＋杆菌数、G^＋球菌数均有显著增加,差异均有显著性;A、B组肠道杆球菌比值和G^＋杆菌数占肠道总菌群数比     

Putting the genes into community genetics

As part of the long‐term fusion of evolutionary biology and ecology (Ford, 1964), the field of community genetics has made tremendous progress in describing the impacts of plant genetic variation on community and ecosystem processes. In the “genes‐to‐ecosystems” framework (Whitham et al., 2003), genetically based traits of plant species have ecological consequences, but previous studies have not identified specific plant genes responsible for community phenotypes. The study by Barker et al. (2019) in this issue of Molecular Ecology uses an impressive common garden experiment of trembling aspen (Figure 1) to test for the genetic basis of tree traits that shape the insect community composition. Using a Genome‐Wide Association Study (GWAS), they found that genomic regions associated with phytochemical traits best explain variation in herbivore community composition, and identified specific genes associated with different types of leaf‐modifying herbivores and ants. This is one of the first studies to identify candidate genes underlying the heritable plant traits that explain patterns of insect biodiversity.     

吉富罗非鱼IGF2基因分离及其单核苷酸多态性与体型、增重相关性

胰岛素样生长因子2(insulin-like growth factor2,IGF2)是控制动物生长和脂肪沉积的重要基因之一。本文采用PCR方法分离了吉富罗非鱼(GIFT strain Nile tilapia Oreochromis niloticus)IGF2基因5475bp,包含由4个外显子组成的整个阅读框669bp以及3个内含子。通过比对吉富罗非鱼10个个体IGF2序列,共发现11处单核苷酸多态性(single nucleotide polymorphism,SNP)位点,本文检测了内含子1的621nt(C/T)和外显子3的161nt(A/G)两位点在192尾吉富罗非鱼中的基因型分布,并分析不同基因型与体型、增重的相关性。使用四引物扩增受阻体系PCR检测内含子1的621nt基因型,结果显示,CC、CT、TT基因型频率在雄鱼中分别为0.32、0.32、0.36,在雌鱼中分别为0.38、0.38、0.24;与体型、增重的相关性分析表明,此位点不同基因型只与雄鱼体型(体高/体长)显著相关(P0.05),CC型个体显著高于CT和TT型个体。外显子3的A/G转换导致了MSPⅠ酶切位点改变,使用PCR-RFLP法检测该位点基因型,结果显示整个群体中不存在AA基因型,在雄鱼中,GG、AG基因型频率分别为0.71、0.29,而雌鱼中则为0.75和0.25;与体型、增重的相关性分析表明,此位点不同基因型只与雄鱼增重极显著相关(P0.01),GG型的雄鱼明显较AG型增重快。