The planarian Schmidtea mediterranea as a model system for the discovery and characterization of cell‐penetrating peptides and bioportides

The general utility of the planarian Schmidtea mediterranea, an organism with remarkable regenerative capacity, was investigated as a convenient three‐dimensional model to analyse the import of cell‐penetrating peptides (CPPs) and bioportides (bioactive CPPs) into complex tissues. The unpigmented planarian blastema, 3 days post head amputation, is a robust platform to assess the penetration of red‐fluorescent CPPs into epithelial cells and deeper tissues. Three planarian proteins, Ovo, ZicA and Djeya, which collectively control head remodelling and eye regeneration following decapitation, are a convenient source of novel cationic CPP vectors. One example, Djeya1 (RKLAFRYRRIKELYNSYR), is a particularly efficient and seemingly inert CPP vector that could be further developed to assist the delivery of bioactive payloads across the plasma membrane of eukaryotic cells. Eye regeneration, following head amputation, was utilized in an effort to identify bioportides capable of influencing stem cell‐dependent morphogenesis. These investigations identified the tetradecapeptide mastoparan (INLKALAALAKKIL) as a bioportide able to influence the gross morphology of head development. We conclude that, compared with cellular monolayers, the S. mediterranea system provides many advantages and will support the identification of bioportides able to selectively modify the biology of totipotent neoblasts and, presumably, other mammalian stem cell types.     

嗜酸乳杆菌对人舌癌细胞增殖的影响

目的研究嗜酸乳杆菌对人舌癌细胞Tca8113增殖及细胞周期的影响。方法体外培养Tca8113细胞,分别将不同稀释度（原液和4、16倍稀释）的嗜酸乳杆菌上清液、灭活菌液和无细胞提取物与Tca8113细胞共培养,采用倒置显微镜观察细胞形态并行细胞计数,磺酰罗丹明B（SRB）法测定细胞增殖率,流式细胞术分析嗜酸乳杆菌各组分对Tca8113细胞增殖及细胞周期的影响,激光扫描共聚焦显微镜（CLSM）检测细胞内自由基和Ca2+含量。结果嗜酸乳杆菌各组分作用于Tca8113细胞48 h后,在倒置显微镜下观察,细胞由菱形、多角形、铺路石状变为细长形。细胞计数与SRB实验分析：在不同稀释度同一培养时间与不同培养时间同一稀释度培养条件下,嗜酸乳杆菌各组分均可明显抑制Tca8113细胞增殖,抑制力随稀释度增加而降低,随培养时间延长而增强。流式细胞术分析：嗜酸乳杆菌各组分作用Tca8113细胞48 h后,细胞增殖指数降低（P<0.01）。CLSM检测：嗜酸乳杆菌各组分作用Tca8113细胞48 h后细胞内自由基和Ca2+含量均升高（P<0.01）。结论嗜酸乳杆菌代谢产物、灭活菌液、无细胞提取物均可抑制Tca8113细胞增殖,可能与菌体及其代谢产物引起细胞内自由基含量增多、Ca2+超载有关。     

肝硬化患者肠道微生态的初步研究

目的 了解肝硬化患者粪便中的类杆菌、双歧杆菌、肠球菌、大肠杆菌、直肠真杆菌-球形梭菌、梭状芽胞杆菌情况,比较肝硬化患者与健康对照组之间肠道微生态的差异. 方法 收集2010年3月至12月遵义市第一人民医院消化科收治的肝硬化患者29例,并以13名健康在校大学生作对照,收集粪便标本测量其pH值、细菌比浊度并在玻片上行荧光原位杂交,用激光共聚焦扫描显微镜对细菌进行计数观察.比较肝硬化患者及健康对照者的粪便pH值、细菌比浊度及不同细菌计数差异,比较不同病因(肝炎性、酒精性和非酒精性)及肝硬化程度(Child-Pugh分级)患者间的细菌计数差异.独立样本t检验或非参数检验Kruskal-Wallis法进行统计学分析. 结果 肝硬化组患者粪便pH值高于健康对照组(6.79±0.64比6.18±0.74,t=2.607,P＜ 0.05),细菌比浊度与健康对照间的差异无统计学意义(1.15±0.59比1.39±1.01,t=0.960,P＞0.05).肝硬化患者粪便中双歧杆菌、类杆菌、真杆菌-直肠梭菌、肠球菌、大肠杆菌、梭状芽胞杆菌均较健康对照组明显减少(每个视野中细菌个数的中位数分别为32.14个比289.67个、17.09个比128.38个、21.91个比91.48个、25.78个比175.92个、13.11个比80.18个和34.68个比173.84个,Z值分别为-4.006、-4.34、-4.399、-4.174、-3.558和-3.95,P值均＜ 0.01).细菌数量的这种改变在肝硬化不同病因及严重程度患者间无明显差异(P值均＞0.05).结论 肝硬化患者肠道中类杆菌、双歧杆菌、肠球菌、大肠杆菌、直肠真杆菌-球形梭菌、梭状芽胞杆菌数量减少,并致肠腔pH升高;但肠道微生态的变化在肝硬化不同病因及严重程度患者间无明显差异.     

Electrical and optical study of nerve impulse-evoked ATP-induced, P2X-receptor-mediated sympathetic neurotransmission at single smooth muscle cells in mouse isolated VAS deferens

Simultaneous electrophysiology and confocal microscopy were used to investigate purinergic neurotransmission at single smooth muscle cells (SMCs) in mouse isolated vas deferens, and to explore the relationship between two high-resolution P2X-receptor-mediated measures of per pulse ATP release: transient peaks in the first time derivative of the rising phase of excitatory junction potentials (EJPs) recorded in single SMCs ('discrete events'; DEs) and neuroeffector Ca(2+) transients (NCTs) in the impaled SMCs. This study shows that discrete events represent neurotransmitter release onto the impaled cell. First, the median amplitude of the first derivative of the EJP was larger when there was a coincident NCT in the impaled cell, compared with instances when no coincident NCT occurred. Second, the time-to-peak amplitude of the first derivative was shorter if there was a coincident NCT in the impaled cell, compared with when no coincident NCT was observed within the field. Surprisingly, first derivative amplitude increased with the distance (of the corresponding NCT) from the microelectrode. The microelectrode did not locally inhibit the functional quantal size as there was no effect of distance on the normalized NCT amplitude. When the significant effect of distance (between the microelectrode and NCTs) on the first derivative amplitude was removed, there was no correlation between the unstandardized residual (of distance vs. first derivative amplitude) and NCT amplitude. The absence of a correlation between DE and NCT amplitudes suggests that the NCT amplitude is a poor measure of quantal size. The usefulness of NCTs hence lies primarily in locating neurotransmitter release and measuring changes in local release probability.     

以激光扫描共聚焦显微镜三维重建肾小球系膜细胞

为进一步研究肾小球系膜细胞的结构与功能，利用激光扫描共聚焦显微镜对体外培养的人肾小球系膜细胞进行断层扫描及三维重建，并与普通荧光显微镜的图像进行了比较。结果表明，共聚焦显微镜可以清晰地显示系膜细胞的立体形态以及纤维连接蛋白在细胞质内不同层面的分布状况及分布强度，这为从立体结构方面对系膜细胞深入研究提供了一个新的方法。