犬贾第虫核糖体16sRNA部分序列克隆及测定

目的：获取犬贾第虫核糖体16sRNA基因序列。方法：从犬贾第虫包囊中，快速提取DNA，并以DNA为模板，利用热启动PCR技术扩增出一611bp的预计大小的基因片段，纯化回收后，与PMD18－T载体连接转化到DH5a大肠杆菌中，筛选到阳性克隆经PCR、EcoR I和HindⅢ双酶切鉴定，并用双脱氧链末端终止法测定DNA序列，登陆BLAST进行同源性比较和分析。结果：获得了长度为611bp的基因序列，并发现与犬贾第虫核糖体的同源性最高达99％。结论：获得了犬贾第虫核糖体16sRNA的部分基因序列，为研究其在核酸进化领域中的地位和PCR法快速诊断贾第虫病提供了理想的基因材料。     

RNAs actively cycle on the Sm-like protein Hfq

Hfq, a protein required for small RNA (sRNA)-mediated regulation in bacteria, binds RNA with low-nanomolar K(d) values and long half-lives of complexes (>100 min). This cannot be reconciled with the 1- 2-min response time of regulation in vivo. We show that RNAs displace each other on Hfq on a short time scale by RNA concentration-driven (active) cycling. Already at submicromolar concentrations of competitor RNA, half-lives of RNA-Hfq complexes are ≈1 min. We propose that competitor RNA associates transiently with RNA-Hfq complexes, RNAs exchange binding sites, and one of the RNAs eventually dissociates. This solves the "strong binding-high turnover" paradox and permits efficient use of the Hfq pool.     

念珠状链杆菌引起鼠咬热1例

目的 通过对一株念珠状链杆菌及其引发的鼠咬热病例的回顾性分析,为临床微生物室和临床医生提供诊治经验。方法 病例回顾性分析：患者因被老鼠咬伤左手拇指引起发热就诊,入院后进行血培养,并用美华Ma120、梅里埃Vitek 2细菌鉴定系统、杭州滨河微量生化管、梅里埃TM质谱仪和16SrRNA基因测序进行细菌鉴定。临床给予阿莫西林氟氯西林联合左氧氟沙星抗感染治疗12 d。结果 血培养分离出革兰阴性呈链状、菌体有念珠状肿胀的L型细菌;该菌用美华Ma120、梅里埃Vitek 2细菌鉴定系统、杭州滨河微量生化管、梅里埃TM质谱仪均无法鉴定;16sRNA基因测序结果显示该菌与念珠状链杆菌的相似度为100%;临床确诊为念珠状链杆菌型鼠咬热,用阿莫西林氟氯西林联合左氧氟沙星治疗有效。结论 念珠状链杆菌能引起人类鼠咬热,该菌用16sRNA基因测序能准确鉴定,常规细菌鉴定仪和质谱仪均难以鉴定。临床医生对于有鼠咬史的患者,血液中检出革兰阴性呈链状、菌体有念珠状肿胀的L型细菌时需考虑念珠状链杆菌引发鼠咬热的可能。     

舒林酸联合双歧杆菌三联活菌治疗家族性腺瘤性息肉病的作用及其机制初探

目的探讨舒林酸联合双歧杆菌三联活菌(培菲康)治疗家族性腺瘤性息肉病(FAP)的疗效及其机制。 方法收集2013年1月1日至2022年1月1日在上海交通大学医学院附属瑞金医院就诊的FAP患者,采用随机数字表法,将经胃肠镜检查及组织病理学检查确诊的这些FAP患者,分为舒林酸组、培菲康组、舒林酸联合培菲康组3组。舒林酸组口服舒林酸400 mg/d,疗程为1年;培菲康组口服培菲康6粒/d,疗程1年;舒林酸联合培菲康组,口服舒林酸400 mg/d+6粒培菲康/d,疗程1年。每4个月结肠镜复查1次,观察每组患者一般情况,腺瘤的病理类型、大小、数目。采用16sRNA高通量测序分析患者粪便菌群变化Western blot检测凋亡抑制蛋白Bcl-2的表达。 结果入组患者共90例,每组30例,舒林酸联合培菲康组于治疗后4、8、12个月腺瘤的病理类型：管状腺瘤分别占活检腺瘤总数分别为90.5%、94.4%、99.2%;绒毛管状腺瘤占9.5%、5.6%、0.8%;舒林酸组分别为85.3%、90.4%、95.2%,培菲康组分别为80.5%、85.3%、90.2%。舒林酸+培菲康组与培菲康组、舒林酸组比较,差异有统计学意义(P<0.05)16sRNA测序提示舒林酸联合培菲康组厚壁菌门和放线菌门比例增加,而拟杆菌门比例降低。Western blot显示舒林酸联合培菲康组Bcl-2表达显著较其它组降低(P<0.05)。 结论舒林酸联合培菲康能有效的治疗FAP,其疗效优于单纯服用舒林酸组和培菲康组。可能的机制与降低Bcl-2,减少对凋亡的抑制,促进了腺瘤的凋亡,同时改善了肠内环境菌群有关。     

Antibodies specific for nucleic acids and applications in genomic detection and clinical diagnostics

Detection of nucleic acids using antibodies is uncommon. This is in part because nucleic acids are poor immunogens and it is difficult to elicit antibodies having high affinity to each type of nucleic acid while lacking cross-reactivity to others. We describe the origins and applications of a variety of anti-nucleic acid antibodies, including ones reacting with modified nucleosides and nucleotides, single-stranded DNA, double-stranded DNA, RNA, DNA:RNA hybrids, locked-nucleic acids or peptide nucleic acid:nucleic acid hybrids. Carefully selected antibodies can be excellent reagents for detecting bacteria, viruses, small RNAs, microRNAs, R-loops, cancer cells, stem cells, apoptotic cells and so on. The detection may be sensitive, simple, rapid, specific, reproducible, quantitative and cost-effective. Current microarray and diagnostic methods that depend on cDNA or cRNA can be replaced by using antibody detection of nucleic acids. Therefore, development should be encouraged to explore new utilities and create a robust arsenal of new anti-nucleic acid antibodies.