哮喘患儿口咽部菌群分析及3株优势菌的拮抗作用

了解哮喘患儿呼吸道菌群多样性及其组成特征, 同时研究所分离的3株优势菌对流感嗜血杆菌的抑制作用, 探究哮喘与呼吸道菌群之间的关系。

采集沈阳市儿童医院呼吸内科2019年3月至2019年12月收治的21例4~12岁急性发作期哮喘患儿咽拭标本, 并同时采集23例同龄健康儿童的咽拭标本作为对照, 对呼吸道菌群进行分离培养、纯化和16S rRNA鉴定。采用牛津杯法检测健康儿童口咽部分离的3株优势菌对流感嗜血杆菌的拮抗作用。

哮喘和健康儿童呼吸道培养出的需氧菌(t=2.143, P=0.038)和厌氧菌(t=3.270, P=0.002)的密度差异有统计学意义。哮喘患儿咽部需氧菌以肺炎链球菌和流感嗜血杆菌为主, 厌氧菌以韦荣球菌为主。健康儿童咽部需氧菌以缓症链球菌和口腔链球菌为主, 厌氧菌以干酪乳杆菌为主。健康儿童口咽部的3株优势菌对哮喘儿童口咽部流感嗜血杆菌的生长具有显著抑制作用。

与健康儿童相比, 哮喘患儿口咽部菌群发生紊乱, 且哮喘患儿口咽部需氧菌、厌氧菌密度显著增加。健康儿童口咽部的某些优势菌可能对哮喘致病菌的定植有一定的拮抗作用。

     

国际基因工程机器大赛高中赛道发展概况

国际基因工程机器大赛(international genetically engineered machine competition,简称iGEM竞赛)是合成生物学国际顶级大学生学术竞赛。iGEM竞赛赛况及项目成果受到Science、Nature、Scientific American、The Economist、英国广播公司(BBC)等顶级学术期刊或国际媒体的关注,具有广泛的国际影响力。吸引了来自世界40多个国家和地区的队伍参赛。2011年起开始有高中队参赛,参赛队伍数量逐年增加,高中生日益成为推动iGEM竞赛及合成生物学发展的重要力量之一,iGEM竞赛也成为培养中学生核心素养的重要平台。基于2017–2021年全球高中队参赛情况,本文总结了高中队赛道规则、选题倾向及获奖情况,进一步分析iGEM竞赛对高中生核心素养培养的意义,探究全球高中参赛队伍的发展趋势,为未来高中参赛队伍建设提供理论参考。     

Analysis of Fibroblast growth factor 15 cis-elements reveals two conserved enhancers which are closely related to cardiac outflow tract development

Fibroblast growth factor 15 (Fgf15) is expressed in the developing mouse central nervous system and pharyngeal arches. Fgf15 mutant mice showed defects of the cardiac outflow tract probably because of aberrant behavior of the cardiac neural crest cells. In this study, we examined cis-elements of the Fgf15 gene by transient transgenic analysis using lacZ as a reporter. We identified two enhancers: one directed lacZ expression in the hindbrain/spinal cord and the other in the posterior midbrain (pmb), rhombomere1 (r1) and pharyngeal epithelia. Interestingly, human genomic regions which are highly homologous to these two mouse enhancers showed almost the same enhancer activities as those of mice in transgenic mouse embryos, indicating that the two enhancers are conserved between humans and mice. We also showed that the mouse and human pmb/r1 enhancer can regulate lacZ expression in chick embryos in almost the same way as in mouse embryos. We found that the lacZ expression domain with this enhancer was expanded by ectopic Fgf8b expression, suggesting that this enhancer is regulated by Fgf8 signaling. Moreover, over-expression of Fgf15 resulted in up-regulation of Fgf8 expression in the isthmus/r1. These findings suggest that a reciprocal positive regulation exists between Fgf15 and Fgf8 in the isthmus/r1. Together with cardiac outflow tract defects in Fgf15 mutants, the conservation of enhancers in the hindbrain/spinal cord and pharyngeal epithelia suggests that human FGF19 (ortholog of Fgf15) is involved in early development and the distribution of cardiac neural crest cells and is one of the candidate genes for congenital heart defects.     

Quantum dot-based cell motility assay

Motility and migration are measurable characteristics of cells that are classically associated with the invasive potential of cancer cells, but in vitro assays of invasiveness have been less than perfect. We previously developed an assay to monitor cell motility and migration using water-soluble CdSe/ZnS nanocrystals; cells engulf the fluorescent nanocrystals as they crawl across them and leave behind a fluorescent-free trail. We show here that semiconductor nanocrystals can also be used as a sensitive two-dimensional in vitro invasion assay. We used this assay to compare the behavior of seven different adherent human cell lines, including breast epithelial MCF 10A, breast tumor MDA-MB-231, MDA-MB-435S, MCF 7, colon tumor SW480, lung tumor NCI H1299, and bone tumor Saos-2, and observed two distinct behaviors of cancer cells that can be used to further categorize these cells. Some cancer cell lines demonstrate fibroblastic behaviors and leave long fluorescent-free trails as they migrate across the dish, whereas other cancer cells leave clear zones of varying sizes around their periphery. This assay uses fluorescence detection, requires no processing, and can be used in live cell studies. These features contribute to the increased sensitivity of this assay and make it a powerful new tool for discriminating between non-invasive and invasive cancer cell lines.     

Secondary heart field contributes myocardium and smooth muscle to the arterial pole of the developing heart

The arterial pole of the heart is the region where the ventricular myocardium continues as the vascular smooth muscle tunics of the aorta and pulmonary trunk. It has been shown that the arterial pole myocardium derives from the secondary heart field and the smooth muscle tunic of the aorta and pulmonary trunk derives from neural crest. However, this neural crest-derived smooth muscle does not extend to the arterial pole myocardium leaving a region at the base of the aorta and pulmonary trunk that is invested by vascular smooth muscle of unknown origin. Using tissue marking and vascular smooth muscle markers, we show that the secondary heart field, in addition to providing myocardium to the cardiac outflow tract, also generates prospective smooth muscle that forms the proximal walls of the aorta and pulmonary trunk. As a result, there are two seams in the arterial pole: first, the myocardial junction with secondary heart field-derived smooth muscle; second, the secondary heart field-derived smooth muscle with the neural crest-derived smooth muscle. Both of these seams are points where aortic dissection frequently occurs in Marfan's and other syndromes.     

呼吸道与非呼吸道标本主要非发酵菌分离株的耐药性比较

目的对2 229份住院患者标本进行分离培养,并对非发酵菌分离株进行药敏试验,了解呼吸道与非呼吸道主要分离株的耐药率差异,以便指导临床合理使用抗菌药物。方法收集2008年8月至2010年10月分离自患者呼吸道、非呼吸道标本的革兰阴性非发酵菌,采用VITEK-32全自动微生物鉴定药敏仪进行细菌鉴定,药敏测定采用K-B法,并比较呼吸道与非呼吸道标本所检出的主要革兰阴性非发酵菌对抗菌药物的耐药率差异。结果共检出非发酵菌556株,其中呼吸道标本366株,非呼吸道标本190株,前3位非发酵菌分离株分别为铜绿假单胞菌、鲍曼不动杆菌和嗜麦芽窄食单胞菌。非发酵菌菌株ESBLs、AmpC、MBL、同产ESBLs+AmpC和同产ESBLs+MBL检出率分别为17.62%、13.67%、14.39、12.23%和6.12%,其中呼吸道标本分离株铜绿假单胞菌的ESBLs、AmpC检出率明显高于非呼吸道标本(均P<0.05),鲍曼不动杆菌的ESBLs、AmpC检出率明显低于非呼吸道标本(均P<0.05);呼吸道、非呼吸道标本的铜绿假单胞菌、鲍曼不动杆菌和嗜麦芽窄食单胞菌分离株对多种抗生素的耐药率不同,差异均有统计学意义(均P<0.05)。结论呼吸道与非呼吸道标本分离的主要非发酵菌分离株对同一抗菌药物耐药率不同,治疗不同部位非发酵菌引起的感染,要考虑由于感染部位不同而产生的耐药性以及药物有效浓度的差异,根据药敏结果合理使用抗菌药物。     

胶蚧属昆虫的自然分布扩散及地理起源(半翅目:胶蚧科)

在对南亚、东南亚及邻近地区胶蚧属昆虫分布资料归纳的基础上,结合近年实地调查资料,提出了胶蚧属昆虫的自然分布、扩散路线及地理起源。结果如下:胶蚧属昆虫主要分布在南亚、东南亚及邻近地区,主要包括中国、印度、巴基斯坦、孟加拉国、尼泊尔、不丹、缅甸、泰国、老挝、越南、马来西亚、印度尼西亚、菲律宾、澳大利亚等地。胶蚧属昆虫有2个分布区,即南亚分布区和东南亚分布区。国际流域恒河、印度河、布拉马普特拉河、萨尔温江-怒江、澜沧江-湄公河、元江-红河及它们的部分支流是胶蚧属昆虫扩散的通道。南亚扩散路线以印度为中心,分别向北、向西和向东3个方向扩散;东南亚扩散路线以马来西亚为中心,向北扩散。胶蚧属昆虫有2个地理起源,南亚范围以印度为中心,东南亚范围内以马来西亚为中心。胶蚧属昆虫的寄主植物是其分布扩散的先决条件,气候条件是限制分布扩散的关键因子。