A型产气荚膜梭菌重组菌株BL21（DE3）

采用限制性核酸内切酶酶切鉴定含α毒素突变基因的重组质粒,同时用SDS-PAGE检测不同条件下α毒素突变基因的表达情况。经酶切鉴定证实重组质粒pXMCPA02含有α毒素突变基因且基因序列和阅读框架正确。同时以IPTG为诱导剂诱导α毒素突变基因表达并对其表达条件进行优化。优化表达的结果是：培养基pH7.5,培养温度37℃,IPTG浓度0.8 mmol/L,菌体生长密度OD600达到0.8时加入IPTG,诱导时间5 h,此时重组菌株pXMCPA02蛋白表达量为35%。从而实现了α毒素突变基因的高效表达,为A型产气荚膜梭菌α毒素基因工程菌苗的生产工艺研究提供了可靠的试验数据。     

鸡SIgA的纯化及兔抗鸡SIgA抗体的制备

采用改良硫酸铵盐析法从鸡胆汁中分离鸡分泌型免疫球蛋白A(S IgA),M acro-prep H igh Q阴离子交换柱层析提纯,经二次过柱后获得的鸡S IgA浓度达22 m g/mL。SDS聚-丙烯酰胺凝胶电泳检测表明,重链分子质量为63~64 ku,轻链为26~28 ku,J链约16 ku。用纯化的鸡S IgA免疫兔,所得的抗血清经双向琼脂扩散,证明兔抗鸡S IgA血清效价达1¨128。     

拟南芥室内培养技术研究

拟南芥室内培养的方法有土培法、蛭石培养法、沙培法、MS培养基法、移栽法、基质培养法和水培法,文章对这些方法的优缺点进行讨论。     

Microbial Community Changes Along a Land-Use Gradient of Desert Soil Origin

Soil harbors remarkably stabilize bacterial communities at the phylum level.However,no two soils have exactly the same structure of bacterial phyla.The structure of microbial community is strongly influenced by the type of land-use through changes in soil attributes.Using high-throughput pyrosequencing and quantitative polymerase chain reaction techniques,soil microbial community structures were investigated along a land-use gradient of 100- and 27-year farmlands,a 33-year Pinus forest,a 28-year poplar forest,and a 21-year shrubland,as well as a native desert from which all cultivated systems were converted.The results revealed that the dominant phylotypes in the native soil comprised primarily of Alphaproteobacteria,Actinobacteria,Bacteroidetes,and Firmicutes,accounting for >71.4%of the total bacterial 16S rRNA sequence reads.Changes in land-use led to a significant decrease in these dominant phylotypes down to 33.4%.In contrast,the phylotypes with low abundance,such as Acidobacteria,Chloroflexi,Nitrospira,and Gammaproteobacteria,increased sharply from 4.5%-5.9%in the native soil to 20.9%-30.2%of the total 16S rRNA gene sequences in the cultivated soils except for the soil from the shrubland.These contrasting changes in the major taxa appear to be correlated with the changes in soil attributes.For instance,bacterial and archaeal amoA genes were found to be 960-and 3 800-fold more abundant in the soil from the 100-year farmland than the native soil.The changes in numerically less dominant nitrifying phylotypes are consistent with soil inorganic nitrogen dynamics.Quantification of the 16S rRNA genes demonstrated that bacteria and archaea were about two to three orders of magnitude more abundant in the cultivated soil than in the native soil.Hence,land-use type affects the soil bacterial community structure,which has profound consequences on ecosystem function.     

基于FIA*-APF算法的蟹塘投饵船动态路径规划

为了提高无人投饵船在含障碍物河蟹养殖池塘自主巡航的作业效率和安全性,该研究提出基于改进A*算法与人工势场法相融合（fusion of improved A* and artificial potential field,FIA*-APF）的蟹塘投饵船动态路径规划算法。首先引入动态加权因子优化A*算法评价函数;其次加入转折惩罚函数并删除冗余点,接着利用B样条曲线对全局路径进行平滑处理;最后将改进A*算法得到的全局路径作为改进人工势场法中的引力路径,生成投饵船自主巡航高效路径。根据养殖池塘创建静态和动态2种仿真环境,分别对传统人工势场法（traditional artificial potential field,TAPF）、基于A*和人工势场法的融合算法（the A* and artificial potential field,TA*-APF）和FIA*-APF算法的性能进行20次测试。仿真试验结果表明：2种环境下,FIA*-APF算法的平均规划时间是TAPF算法的17.23%,是TA*-APF算法的51.96%,平均指令节点数量比TAPF算法减少50.64%,比TA*-APF算法减少65.03%,平均路径长度比TA*-APF算法减少2.82%。蟹塘试验结果表明：FIA*-APF算法的规划时间为TAPF算法的38.16%,为TA*-APF的62.42%,路径长度比TAPF算法减少29.13%,比TA*-APF减少10.15%;另外,TAPF和TA*-APF算法规划路径上大于60°的转角分别是FIA*-APF算法的3.28和2.62倍,大于100°的转角分别是FIA*-APF算法的3.73和1.67倍,该研究算法规划的路径更高效平滑。研究结果可为无人投饵船自主导航提供参考。     

PICC在新生儿重症监护室中的应用及护理体会

目的 分析新生儿重症监护室中PICC的临床应用效果及护理体会。方法 回顾分析我院重症监护室2018年4月~2020年4月所收治44例新生儿临床资料（均为早产儿）,随机划分为对照组与观察组,每组各22例,均行外周穿刺中心静脉导管植入术,并分别予以常规护理和综合护理干预,比较两组置管成功率、留置时间及并发症发生情况。结果 经阶段性治疗和护理,观察组在导管留置时间、病发率、满意度等各方面明显优于对照组,且差异具有统计学意义（P<0.05）。结论 以PICC对重症监护室新生儿开展治疗时,特别是强化置管期间综合护理方式的介入,可在极大程度上提升置管效果,减少静脉炎、局部渗血、感染等并发症,更有效优化和改善护理满意度,故具有广泛临床应用价值。     

Implication of Echinochrome A in the Plasticity and Damage of Intestinal Epithelium

The diverse therapeutic feasibility of the sea urchin-derived naphthoquinone pigment, Echinochrome A (Ech A), has been studied. Simple and noninvasive administration routes should be explored, to obtain the feasibility. Although the therapeutic potential has been proven through several preclinical studies, the biosafety of orally administered Ech A and its direct influence on intestinal cells have not been evaluated. To estimate the bioavailability of Ech A as an oral administration drug, small intestinal and colonic epithelial organoids were developed from mice and humans. The morphology and cellular composition of intestinal organoids were evaluated after Ech A treatment. Ech A treatment significantly increased the expression of LGR5 (~2.38-fold change, p = 0.009) and MUC2 (~1.85-fold change, p = 0.08). Notably, in the presence of oxidative stress, Ech A attenuated oxidative stress up to 1.8-fold (p = 0.04), with a restored gene expression of LGR5 (~4.11-fold change, p = 0.0004), as well as an increased expression of Ly6a (~3.51-fold change, p = 0.005) and CLU (~2.5-fold change, p = 0.01), markers of revival stem cells. In conclusion, Ech A is harmless to intestinal tissues; rather, it promotes the maintenance and regeneration of the intestinal epithelium, suggesting possible beneficial effects on the intestine when used as an oral medication.     

紫茎泽兰提取物对棉蚜的毒力及其灭蚜机理研究

紫茎泽兰Eupatorium adenophorum提取物对棉蚜Aphis gossypii有很高的毒杀作用。紫茎泽兰乙醇总提物、其氯仿萃取物以及从氯仿萃取物中分离得到的紫茎泽兰素A对棉蚜无翅成蚜的致死中浓度(LC_(50)浸渍法)分别为167.9、224.7、362.8mg/L。试验表明,紫茎泽兰素A对棉蚜钠-钾-三磷酸腺苷酸酶(Na-K-ATPase)活性有明显的抑制作用。棉蚜经2.00mg/ml紫茎泽兰素A溶液处理12h后,其体内的Na-K-ATPase活性仅为对照组棉蚜Na-K-ATPase活性的21.60％。     

棉铃虫YTHDF1基因的表达模式及在核型多角体病毒侵染中的作用

为明确N6-甲基腺苷（N6-methyladenosine,m⁶A）修饰在棉铃虫核型多角体病毒（Helicoverpa armigera nucleopolyhedrovirus,HearNPV）侵染棉铃虫中的作用,根据基因组和转录组数据,对棉铃虫m⁶A结合蛋白基因YTHDF1（YTH domain-containing family protein 1）进行鉴定和分析,利用实时荧光定量PCR技术检测棉铃虫YTHDF1基因的时空表达模式、HearNPV处理后的表达变化情况以及RNA干扰效率,并调查该基因下调后对HearNPV复制及感染HearNPV棉铃虫死亡情况的影响。结果显示,棉铃虫YTHDF1基因开放阅读框全长为2 019 bp,编码672个氨基酸,含有1个保守的YTH结构域,其氨基酸序列与斜纹夜蛾Spodoptera litura同源物序列一致性达87.52%。YTHDF1基因在棉铃虫不同发育阶段均有表达,其中在进入5龄期24 h幼虫中的表达量最高,在2龄取食期幼虫中的表达量最低。YTHDF1基因的空间表达谱呈现一定的组织特异性,在幼虫血细胞和成虫头部的表达量最高。HearNPV侵染棉铃虫后YTHDF1基因上调表达,经RNA干扰使该基因下调后显著抑制了HearNPV多角体蛋白基因polyhedrin的表达并延迟了感染HearNPV棉铃虫的死亡时间。表明YTHDF1基因在HearNPV侵染棉铃虫的过程中发挥着重要作用。