MiR-27靶基因的分析及鉴定

MicroRNAs(miRNAs)是一类约20～25nt的小分子核苷酸,在细胞内的多种生物学过程,如细胞增殖、凋亡、生长、分化和代谢等过程中具有重要的功能。已知miR-27在脂肪细胞和肌肉细胞的发育过程中起了重要作用,其在神经细胞中的表达调节至今仍不清楚。在本研究中,通过miRBase和TargetScan数据库分析了miR-27的靶基因,构建了miR-27的真核表达载体,改造了萤火虫荧光素酶和海肾荧光素酶报告载体,将miR-27的靶基因Bmi1的3′-UTR融合到报告载体中,转染神经胶质瘤细胞,利用双荧光素酶检测系统分析荧光素酶的活性。研究发现miR-27a和miR-27b共同的靶基因主要调节发育过程。MiR-27真核表达载体能产生成熟态的miR-27。MiR-27a、miR-27b或miR-27a和miR-27b联合与Bmi1的3′-UTR的正义序列共转染U343细胞能明显降低萤火虫荧光素酶的活性(分别P0.05,P0.05,P0.01),这提示了Bmi1可能为miR-27的靶基因。     

A test of seven candidate barcode regions from the plastome in Picea (Pinaceae)

DNA barcoding, as a tool for species discrimination, has been used efficiently in animals, algae and fungi, but there are still debates on which DNA region(s) can be used as the standard barcode(s) for land plants. Gymnosperms, especially conifers, are important components of forests, and there is an urgent need for them to be identified through DNA barcoding because of their high frequency of collection in the field. However, the feasibility of DNA barcoding in gymnosperms has not been examined based on a dense species sampling. Here we selected seven candidate DNA barcodes from the plastome (matK, rbcL, rpoB, rpoC1, atpF-atpH, psbA-trnH, and psbK-psbI) to evaluate their suitability in Picea (spruce). The results showed that none of them or their different combinations has sufficient resolution for spruce species, although matK+rbcL might be used as a two-locus barcode. The low efficiency of these candidate barcodes in Picea might be caused by the paternal inheritance of the chloroplast genome, long generation time, recent radiation, and frequent inter-specific hybridization aided by wind pollination. Some of these factors could also be responsible for the difficulties in barcoding other plant groups. Furthermore, the potential of the nuclear LEAFY gene as a land plant barcode was discussed.     

Production of dimethyl sulfide and acrylic acid from dissolved dimethylsulfoniopropionate during the growth of Prorocentrum minimum

Journal of Applied Phycology - Dimethyl sulfide (DMS) is an important and dominant trace gas that is transferred from the ocean to the atmosphere; however, the production of DMS from marine algae...     

Involvement of endogenous hydrogen sulfide in cigarette smoke-induced changes in airway responsiveness and inflammation of rat lung

Hydrogen sulfide (H₂S), recently considered the third endogenous gaseous transmitter, may have an important role in systemic inflammation. We investigated whether endogenous H₂S may be a crucial mediator in airway responsiveness and airway inflammation in a rat model of chronic exposure to cigarette smoke (CS). Rats randomly divided into control and CS-exposed groups were treated with or without sodium hydrosulfide (NaHS, donor of H₂S) or propargylglycine (PPG, inhibitor of cystathionine-γ-lyase [CSE], an H₂S-synthesizing enzyme) for 4-month exposure. Serum H₂S level and CSE protein expression in lung tissue were higher, by 2.04- and 2.33-fold, respectively, in CS-exposed rats than in controls (P < 0.05). Exogenous administration of NaHS to CS-exposed rats alleviated airway reactivity induced by acetylcholine (Ach) or potassium chloride (KCl) by 17.4% and 13.8%, respectively, decreased lung pathology score by 32.7%, inhibited IL-8 and TNF- α concentrations in lung tissue by 34.2% and 31.4%, respectively, as compared with CS-exposed rats (all P < 0.05). However, blocking endogenous CSE with PPG in CS-exposed rats increased airway reactivity induced by Ach or KCl, by 24.1% and 24.5%, respectively, and aggravated lung pathology score, by 44.8%, as compared with CS-exposed rats (all P < 0.01). Incubation in vitro with NaHS, 1–3 mmol/L, relaxed rat tracheal smooth muscle precontracted by Ach or KCl. However, the NaHS-induced relaxation was not blocked by glibenclamide (10^?4 mol/L), L-NAME (10^?4 mol/L), or ODQ (1 μmol/L) or denudation of epithelium. Endogenous H₂S may have a protective role of anti-inflammation and bronchodilation in chronic CS-induced pulmonary injury.     

Effect of Helicobacter pylori infection on Barrett's esophagus and esophageal adenocarcinoma formation in a rat model of chronic gastroesophageal reflux

Objectives: To investigate the relationship between Helicobacter pylori infection and Barrett’s esophagus (BE), a rat model of chronic gastroesophageal reflux with H. pylori infection was established and the degree of inflammation, incidence of BE and esophageal adenocarcinoma (EA) were evaluated. Methods: Eight‐week‐old male specific‐pathogen‐free SD rats were divided into five groups randomly: pseudo‐operation group; esophagojejunum anastomosis (EJA) group; EJA with H. pylori infection group; EJA with H. pylori infection and celecoxib‐treated group; EJA with celecoxib‐treated group. Rats were kept for 30 weeks after surgery. Esophageal lesion was evaluated grossly and microscopically. The expression of COX‐2 and CDX2 was determined by RT‐PCR and immunohistochemistry staining. The level of PGE₂ was assessed by enzyme‐linked immunosorbent assay. Results: Esophageal mucosal injury in the group of EJA with H. pylori infection was decreased than that in EJA group (p < .05). The incidence of BE and EA in rats undergoing EJA with H. pylori infection was increased than in rats undergoing EJA with no statistical difference. Celecoxib treatment decreased the incidence of EA in rats undergoing EJA with H. pylori infection (p < .05). The expression of CDX2 mRNA was decreased in rats with H. pylori infection or treated with celecoxib than in the rats of pseudo‐operation group (p < .05). When compared with those in rats of pseudo‐operation group, the expression of COX‐2 mRNA and the level of PGE₂ were upregulated in rats undergoing EJA irrespective of H. pylori infection (p < .05) and downregulated in rats treated with celecoxib (p < .05). When H. pylori colonized in esophagus, the severity of inflammation and the incidence of BE and EA were increased significantly. Higher levels of COX‐2 expression and PGE₂ were detected in rats with esophageal H. pylori colonization. Conclusions: When H. pylori infect in stomach, it may reduce the severity of inflammation. However, when colonizes in esophagus, H. pylori increases the severity of esophageal inflammation and the incidence of BE and EA. Celecoxib administration attenuates the incidence of EA by inhibiting COX‐2 expression.     

母猪繁殖力性状影响因素分析及遗传参数估计

母猪繁殖力是影响种猪场经济效益的重要因素。文章对纯种大白猪、长白猪、杜洛克猪的8491窝产仔记录进行统计分析,建立固定效应模型对总产仔数、健仔数、初生窝重、弱仔数、死胎数、木乃伊胎数和畸形胎数共7个繁殖性状进行最小二乘分析,分析胎次、配种季节、品种对母猪繁殖性能的影响,同时比较了纯繁和杂交的效果。利用动物模型REML(约束最大似然)方法估计繁殖性状的遗传力和遗传相关。结果表明,胎次、配种季节和品种对总产仔数、健仔数、初生窝重影响极显著(P<0.001),胎次和品种对弱仔数影响极显著(P<0.001),但配种季节对弱仔数影响不显著。胎次对死胎数影响显著(P<0.05),而配种季节和品种对死胎数影响不显著,胎次、配种季节和品种对木乃伊胎、畸形胎数影响不显著。长白♂×大白♀交配组合具有最高的总产仔数、健仔数和初生窝重。繁殖性状遗传力估计结果显示,长白猪初生窝重的遗传力最高,为0.227。其余性状遗传力均在0.2以下,为低遗传力性状。3个品种母猪的健仔数与初生窝重、总产仔数与健仔数之间的遗传相关达0.96以上。研究结果为降低非传染性因素造成的种母猪产仔数低的问题以及种猪场对母猪繁殖力的选育提高提供了参考数据和理论依据。     

运输时间和密度对翘嘴鲌皮质醇、耗氧率及氧气袋内水质的影响

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