Tbx18-Cre基因敲入小鼠的繁殖、鉴定及其应用

为了探讨Tbx18-Cre基因敲入小鼠(Tbx18:Cre knock-in Mus musculus)的繁殖、鉴定及Tbx18基因敲除小鼠和遗传示踪小鼠模型的应用,将Tbx18-Cre基因敲入杂合子小鼠进行繁殖,应用PCR法鉴定其子代基因型。将子代雌雄杂合子小鼠互交,应用H.E染色观察Tbx18基因敲除胚鼠心的形态学变化。将杂合子小鼠与RosaEYFP报告小鼠交配,应用心冰冻切片技术观察Tbx18:Cre/Rosa26REYFP双转基因遗传示踪胚鼠心内Tbx18阳性心外膜祖细胞发育命运。结果表明,用于繁殖、基因敲除研究及基因遗传示踪的子代基因型均符合孟德尔遗传规律。同时心H.E染色和心冰冻切片发现,Tbx18敲除小鼠心窦房结发育存在缺陷,而Tbx18阳性心外膜祖细胞是心发育重要的祖细胞来源。研究结果揭示,Tbx18-Cre基因敲除小鼠是研究先天性心脏病发病机制的理想模式动物,Tbx18阳性心外膜祖细胞可能是心脏病患者心脏修复和再生潜在的种子细胞。     

Saccharothrix yanglingensis sp. nov., an antagonistic endophytic actinomycete isolated from cucumber plant

An endophytic actinomycete strain, designated Hhs.015^T, was isolated from roots of cucumber seedlings. The endophytic isolate was identified by means of a polyphasic taxonomic approach. On the basis of 16S rRNA gene sequence similarities, strain Hhs.015^T was closely related to members of the genus Saccharothrix. DNA–DNA hybridization with the four closest relatives, Saccharothrix longispora NRRL B-16116^T, Saccharothrix xinjiangensis NRRL B-24321^T, Saccharothrix autraliensis CGMCC 4.1355^T and Saccharothrix espanaensis CGMCC 4.1714^T, gave similarity values of 33.8, 28.2, 44.1 and 29.5%, respectively, which indicated that strain Hhs.015^T represents a novel species of the genus Saccharothrix. This is consistent with the morphological, physiological and chemotaxonomic data. As a whole, these results suggest that strain Hhs.015^T represents a novel Saccharothrix species. The name Saccharothrix yanglingensis sp. nov. is proposed, with the type strain Hhs.015^T (=CGMCC 4.5627^T = KCTC 19722^T).     

miR-671-5p Attenuates Neuroinflammation via Suppressing NF-κB Expression in an Acute Ischemic Stroke Model

Neurochemical Research - This study was designed to investigate the role of miR-671-5p in in vitro and in vivo models of ischemic stroke (IS). Middle cerebral artery occlusion and reperfusion...     

A novel COL7A1 gene mutation causing pretibial epidermolysis bullosa: Report of a Chinese family with intra-familial phenotypical diversity

Pretibial epidermolysis bullosa (PEB) is an extremely rare subtype of dominant dystrophic epidermolysis bullosa (DDEB) caused by mutation of the COL7A1 gene. More than 730 mutations have been identified in patients with DDEB, but only five mutations have been found to be related to PEB. In this study, a novel heterozygous nucleotide G > T transition at position 6101 in exon 73 of COL7A1 was detected, which resulted in a glycine to valine substitution (G2034V) in the triple-helical domain of type-VII collagen. This is the first report to show that one mutation caused a broad range of severity of disease in one family with PEB. These data suggest that c.6101G > T may influence the phenotype of PEB. They also contribute to the expanding database on COL7A1 mutations.     

菌群失调腹泻抗生素造模对小鼠肠黏膜的影响

目的研究抗生素造模对菌群失调腹泻小鼠肠黏膜的影响。方法正常组给予无菌生理盐水0.35m L/(只·次)灌胃,其余各组采用头孢拉定胶囊和硫酸庆大霉素注射液用无菌生理盐水配成浓度为62.5g/L抗生素混合液0.35 m L/(只·次)灌胃。每天2次,连续5 d。造模成功后,采集小鼠空肠、回肠和结肠,分别测量绒毛高度、隐窝深度、淋巴细胞数和肠黏膜厚度,观察肠黏膜情况。结果菌群失调腹泻抗生素造模后,空肠、回肠和结肠的隐窝深度及肠黏膜厚度与正常组相比,差异无统计学意义(P0.05);造模后的结肠淋巴细胞数与正常组相比较,高于正常组,差异有统计学意义(P0.05),造模后的空肠绒毛高度与正常组相比,明显低于正常组,差异有统计学意义(P0.01)。结论菌群失调腹泻抗生素造模使结肠淋巴细胞数增高,空肠绒毛高度降低。     

Targeted resequencing of a genomic region influencing tameness and aggression reveals multiple signals of positive selection

The identification of the causative genetic variants in quantitative trait loci (QTL) influencing phenotypic traits is challenging, especially in crosses between outbred strains. We have previously identified several QTL influencing tameness and aggression in a cross between two lines of wild-derived, outbred rats (Rattus norvegicus) selected for their behavior towards humans. Here, we use targeted sequence capture and massively parallel sequencing of all genes in the strongest QTL in the founder animals of the cross. We identify many novel sequence variants, several of which are potentially functionally relevant. The QTL contains several regions where either the tame or the aggressive founders contain no sequence variation, and two regions where alternative haplotypes are fixed between the founders. A re-analysis of the QTL signal showed that the causative site is likely to be fixed among the tame founder animals, but that several causative alleles may segregate among the aggressive founder animals. Using a formal test for the detection of positive selection, we find 10 putative positively selected regions, some of which are close to genes known to influence behavior. Together, these results show that the QTL is probably not caused by a single selected site, but may instead represent the joint effects of several sites that were targets of polygenic selection.     

干扰素诱导的跨膜蛋白1在宫颈鳞癌中的表达及其生物学作用

目的:探讨干扰素诱导的跨膜蛋白1(IFITM1)在宫颈鳞癌中的表达及其生物学作用.方法:通过免疫组化、RT-PCR和Western blot检测宫颈鳞癌组织和癌旁组织中IFITM1的表达.使用靶向IFITM1的siRNA(si-IFITM1组)和高表达IFITM1基因的重组pcDNA3.1质粒(pcDNA3.1-si-...     

Delta-opioid receptor-induced late preconditioning is mediated by cyclooxygenase-2 in conscious rabbits

Although activation of delta-opioid receptors is known to induce both early and late preconditioning (PC) against myocardial infarction, the mechanisms for this salubrious effect are unclear. Furthermore, it is unknown whether delta-opioid receptors can also induce late PC against myocardial stunning. By using conscious rabbits (n = 120) in this study, we found that the delta-opioid receptor agonist (+/-)-4-[(alpha-R*)-alpha-[(2S*,5R*)-4-allyl-2,5-dimethyl-1-piperazinyl]-3-hydroxybenzyl]-N,N-diethylbenzamide (BW-373U86) induced late PC against myocardial stunning 24 h after treatment and that this effect was abolished by the selective cyclooxygenase-2 (COX-2) inhibitors N-[2-(cyclohexyloxy)4-nitrophenyl]methanesulfonamide (NS-398) and celecoxib. This protective effect was also abrogated by the selective delta(1)-opioid receptor antagonist 7-benzylidenenaltrexone, indicating that the delta(1)-opioid receptor is necessary for BW-373U86-induced late PC. BW-373U86 did not induce early PC against stunning. In addition, BW-373U86 induced late PC against infarction, which was blocked by NS-398. At 24 h after BW-373U86 administration, myocardial COX-2 protein expression and PGE(2) and 6-keto-PGF(1alpha) levels were significantly increased. These results demonstrate that activation of delta-opioid receptors induces late PC against both stunning and infarction via a COX-2-dependent mechanism.     

Biophysical Studies of Bacterial Topoisomerases Substantiate Their Binding Modes to an Inhibitor

Bacterial DNA topoisomerases are essential for bacterial growth and are attractive, important targets for developing antibacterial drugs. Consequently, different potent inhibitors that target bacterial topoisomerases have been developed. However, the development of potent broad-spectrum inhibitors against both Gram-positive (G⁺) and Gram-negative (G⁻) bacteria has proven challenging. In this study, we carried out biophysical studies to better understand the molecular interactions between a potent bis-pyridylurea inhibitor and the active domains of the E-subunits of topoisomerase IV (ParE) from a G⁺ strain (Streptococcus pneumoniae (sParE)) and a G⁻ strain (Pseudomonas aeruginosa (pParE)). NMR results demonstrated that the inhibitor forms a tight complex with ParEs and the resulting complexes adopt structural conformations similar to those observed for free ParEs in solution. Further chemical-shift perturbation experiments and NOE analyses indicated that there are four regions in ParE that are important for inhibitor binding, namely, α2, the loop between β2 and α3, and the β2 and β6 strands. Surface plasmon resonance showed that this inhibitor binds to sParE with a higher K_D than pParE. Point mutations in α2 of ParE, such as A52S (sParE), affected its binding affinity with the inhibitor. Taken together, these results provide a better understanding of the development of broad-spectrum antibacterial agents.