瞬时受体电位香草酸亚型1激活通过抑制线粒体通透性转换孔开放保护急性心肌梗死小鼠的心肌细胞抗凋亡

瞬时受体电位香草酸亚型1（TRPV1）在心肌缺血激活后可传导心绞痛信号,释放神经肽,减轻心肌梗死后的心肌细胞凋亡。目前,TRPV1激活抑制心肌梗死后细胞凋亡的具体机制尚不清楚。线粒体通透性转换孔（MPTP）的开放与心肌细胞缺血再灌注损伤密切相关,抑制其开放可保护心肌缺血后的心肌细胞抗凋亡。本研究证明,TRPV1激活通过抑制MPTP开放而减少心肌细胞凋亡。首先,本研究利用左冠状动脉前降支结扎术建立了TRPV1基因敲除（TRPV1-/-）和野生型（WT）小鼠心肌梗死模型,辅以环孢素A（CSA）预处理抑制 MPTP开放,比较观察TRPV1、MPTP在心肌梗死中的作用。心肌组织切片氯化三苯基四氮唑（TTC）染色显示,心肌缺血24 h,TRPV1-/-小鼠的心肌梗死面积明显大于WT型小鼠。而经CSA预处理的TRPV1-/-小鼠比TRPV1-/-小鼠梗死面积明显减小。TUNEL检测心肌细胞凋亡指数（AI）揭示,WT型心肌梗死小鼠的AI明显低于TRPV1-/- 心肌梗死小鼠,而CSA预处理明显降低TRPV1-/-小鼠心肌细胞的AI。Western印迹检测胱天蛋白酶3、胱天蛋白酶9、Bcl-2、Bax、p53和细胞色素C（Cyt-C）水平。结果证明,TRPV1的激活可抑制MPTP的开放,减少线粒体Cyt-C的外溢,降低胱天蛋白酶9和胱天蛋白酶3的表达。GENMEN光度法检测MPTP开放实验显示,激活的TRPV1明显抑制了MPTP的开放。本研究证实,急性心肌梗死后的TRPV1激活可能通过抑制MPTP开放而抵抗心肌细胞凋亡,对心肌起保护作用。     

Egg cell-specific promoter-controlled CRISPR/Cas9 efficiently generates homozygous mutants for multiple target genes in Arabidopsis in a single generation

Arabidopsis mutants produced by constitutive overexpression of the CRISPR/Cas9 genome editing system are usually mosaics in the T1 generation. In this study, we used egg cell-specific promoters to drive the expression of Cas9 and obtained non-mosaic T1 mutants for multiple target genes with high efficiency. Comparisons of 12 combinations of eight promoters and two terminators found that the efficiency of the egg cell-specific promoter-controlled CRISPR/Cas9 system depended on the presence of a suitable terminator, and the composite promoter generated by fusing two egg cell-specific promoters resulted in much higher efficiency of mutation in the T1 generation compared with the single promoters.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-015-0715-0) contains supplementary material, which is available to authorized users.     

Characterization of <Emphasis Type="Italic">Prototheca zopfii</Emphasis> Associated with Outbreak of Bovine Clinical Mastitis in Herd of Beijing,China

Prototheca zopfii (P. zopfii) has become an important cause of bovine mastitis in many countries. In the present study, to better understand the occurrence of one clinical mastitis (CM) outbreak due to P. zopfii, the molecular characterization and resistance patterns of the microalga were described. P. zopfii strains were isolated from 17 of 23 quarters, which suffered CM in the outbreak, and 7 of 46 CM recovered quarters before the outbreak, as well as 2 of 75 environmental samples in the dairy farm. All strains were identified as genotype 2 by genotype-specific PCR analysis. Results of in vitro antimicrobial and antifungal susceptibility tests indicated that these strains were resistant to majority of tested drugs, with the only exception of amphotericin B, nystatin, streptomycin, gentamicin, and amikacin. This is the first report about CM outbreak caused by P. zopfii in China. These data suggest that P. zopfii may represent a serious risk in the studied herd, and this microalga could be an important potential pathogen causing mastitis in dairy herds of Beijing.     

肝素钠精制工艺研究

为提高肝素钠粗品效价,改善产品色泽,采用二次盐解、双氧水氧化和脱色等工艺对肝素钠粗品进行精制,并探讨工艺条件对产品效价、收率的影响。结果得到最佳精制工艺条件:盐解质量浓度为2％,盐解pH为8.0,醇沉体积浓度45％,氧化剂(双氧水)体积分数为3％。该精制工艺能够有效地提高效价(平均比粗产品提高1.5倍),收率较高,并具有操作简便、省时等特点。     

A review of Cyclidiinae from China (Lepidoptera,Drepanidae)

The subfamily Cyclidiinae from China is reviewed: two genera and seven species are reported from China. One new subspecies, Cyclidiafractifasciataindistinctasubsp. n., is described. Two new synonyms are established: Cyclidiasubstigmaria (Hübner, 1831) (= Cyclidiasubstigmariabrunna Chu & Wang, 1987, syn. n. = Cyclidiatetraspota Chu & Wang, 1987, syn. n.). One misidentification in Chu & Wang (1987) is corrected. Identification keys and diagnoses for all discussed Chinese species are provided. External features and genitalia are depicted. In addition, results of DNA barcoding for five taxa of Cyclidia are briefly discussed.     

The Direct Actions of GABA, 2’-Methoxy-6-Methylflavone and General Anaesthetics at β3γ2L GABAA Receptors: Evidence for Receptors with Different Subunit Stoichiometries

2’-Methoxy-6-methylflavone (2’MeO6MF) is an anxiolytic flavonoid which has been shown to display GABA_A receptor (GABA_AR) β2/3-subunit selectivity, a pharmacological profile similar to that of the general anaesthetic etomidate. Electrophysiological studies suggest that the full agonist action of 2’MeO6MF at α2β3γ2L GABA_ARs may mediate the flavonoid’s in vivo effects. However, we found variations in the relative efficacy of 2’MeO6MF (2’MeO6MF-elicited current responses normalised to the maximal GABA response) at α2β3γ2L GABA_ARs due to the presence of mixed receptor populations. To understand which receptor subpopulation(s) underlie the variations observed, we conducted a systematic investigation of 2’MeO6MF activity at all receptor combinations that could theoretically form (α2, β3, γ2L, α2β3, α2γ2L, β3γ2L and α2β3γ2L) in Xenopus oocytes using the two-electrode voltage clamp technique. We found that 2’MeO6MF activated non-α-containing β3γ2L receptors. In an attempt to establish the optimal conditions to express a uniform population of these receptors, we found that varying the relative amounts of β3:γ2L subunit mRNAs resulted in differences in the level of constitutive activity, the GABA concentration-response relationships, and the relative efficacy of 2’MeO6MF activation. Like 2’MeO6MF, general anaesthetics such as etomidate and propofol also showed distinct levels of relative efficacy across different injection ratios. Based on these results, we infer that β3γ2L receptors may form with different subunit stoichiometries, resulting in the complex pharmacology observed across different injection ratios. Moreover, the discovery that GABA and etomidate have direct actions at the α-lacking β3γ2L receptors raises questions about the structural requirements for their respective binding sites at GABA_ARs.