Cloning, expression and characterization of alcohol dehydrogenases in the silkworm Bombyx mori

Alcohol dehydrogenases (ADH) are a class of enzymes that catalyze the reversible oxidation of alcohols to corresponding aldehydes or ketones, by using either nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP), as coenzymes. In this study, a short-chain ADH gene was identified in Bombyx mori by 5'-RACE PCR. This is the first time the coding region of BmADH has been cloned, expressed, purified and then characterized. The cDNA fragment encoding the BmADH protein was amplified from a pool of silkworm cDNAs by PCR, and then cloned into E. coli expression vector pET-30a(+). The recombinant His-tagged BmADH protein was expressed in E. coli BL21 (DE3), and then purified by metal chelating affinity chromatography. The soluble recombinant BmADH, produced at low-growth temperature, was instrumental in catalyzing the ethanol-dependent reduction of NAD(+), thereby indicating ethanol as one of the substrates of BmADH.     

TNF-α和IL-13对人肺成纤维细胞胶原蛋白生成的影响

以胶原蛋白过量沉积为主要特征的纤维化是临床肺部疾患常见的病理现象。该研究利用RT-PCR技术检测不同剂量TNF-α和IL-13对人肺成纤维细胞IL-13Rα1、IL-13Rα2和Ⅰ型胶原蛋白转录水平的影响;ELISA检测细胞培养上清sIL-13Rα2分泌量;羟脯氨酸法定量分析各组肺成纤维细胞胶原蛋白生成情况。结果发现:在实验剂量条件下,TNF-α和IL-13对人肺成纤维细胞IL-13Rα1的表达无显著影响;两者均能不同程度地上调IL-13Rα2的表达;与对照组相比,TNF-α对胶原蛋白的表达有下调作用,IL-13则无显著影响。     

颈动脉窦内压的变化速率对反射性降压效应的影响

在成年狗身上制备右侧孤离颈动脉窦,借助灌流装置用饱和氧的任氏液对其进行灌流。灌流压为搏动性的。通过改变每搏泵出量、灌流管道的阻力和弹性来调节灌流压及其变化速率。用多导生理记录仪同步记录股动脉血压、窦内灌流压及其变化速率。本文主要观察窦内压的变化速率对降压反射的影响。在8只狗身上共进行了93次实验。结果表明,在窦内压相同的情况下,灌流压的上升速率愈快,降压效应愈明显,而其下降速率则无显著作用。已有资料证明搏动性窦内压所引起的降压效应较非搏动性压力更为明显。由此可见,狗的颈动脉窦压力感受器不仅对搏动性压力而且对其上升的变化速率也很敏感。     

中国马兜铃属植物的细胞分类学初步研究

本文报道了中国马兜铃属１２种植物的染色体数目和核型分析,发现并确定了ｘ＝８为本属染色体基数之一。本属染色体的共同特征是：小型;以中部（ｍ）,近中部（ｓｍ）着丝点染色体为主;核型类型为１Ａ,２Ａ,３Ａ,１Ｂ,２Ｂ;随体一般处在染色体的长臂上。     

Characterization of Viable Bacteria from Siberian Permafrost by 16S rDNA Sequencing

Abstract Viable bacteria were found in permafrost core samples from the Kolyma-Indigirka lowland of northeast Siberia. The samples were obtained at different depths; the deepest was about 3 million years old. The average temperature of the permafrost is −10°C. Twenty-nine bacterial isolates were characterized by 16S rDNA sequencing and phylogenetic analysis, cell morphology, Gram staining, endospore formation, and growth at 30°C. The majority of the bacterial isolates were rod shaped and grew well at 30°C; but two of them did not grow at or above 28°C, and had optimum growth temperatures around 20°C. Thirty percent of the isolates could form endospores. Phylogenetic analysis revealed that the isolates fell into four categories: high-GC Gram-positive bacteria, β-proteobacteria, γ-proteobacteria, and low-GC Gram-positive bacteria. Most high-GC Gram-positive bacteria and β-proteobacteria, and all γ-proteobacteria, came from samples with an estimated age of 1.8–3.0 million years (Olyor suite). Most low-GC Gram-positive bacteria came from samples with an estimated age of 5,000–8,000 years (Alas suite). Received: 11 April 1996 Accepted: 8 May 1996     

Zfp462 deficiency causes anxiety‐like behaviors with excessive self‐grooming in mice

Zfp462 is a newly identified vertebrate‐specific zinc finger protein that contains nearly 2500 amino acids and 23 putative C2H2‐type zinc finger domains. So far, the functions of Zfp462 remain unclear. In our study, we showed that Zfp462 is expressed predominantly in the developing brain, especially in the cerebral cortex and hippocampus regions from embryonic day 7.5 to early postnatal stage. By using a piggyBac transposon‐generated Zfp462 knockout (KO) mouse model, we found that Zfp462 KO mice exhibited prenatal lethality with normal neural tube patterning, whereas heterozygous (Het) Zfp462 KO (Zfp462^+/?) mice showed developmental delay with low body weight and brain weight. Behavioral studies showed that Zfp462^+/? mice presented anxiety‐like behaviors with excessive self‐grooming and hair loss, which were similar to the pathological grooming behaviors in Hoxb8 KO mice. Further analysis of grooming microstructure showed the impairment of grooming patterning in Zfp462^+/? mice. In addition, the mRNA levels of Pbx1 (pre‐B‐cell leukemia homeobox 1, an interacting protein of Zfp462) and Hoxb8 decreased in the brains of Zfp462^+/? mice, which may be the cause of anxiety‐like behaviors. Finally, imipramine, a widely used and effective anti‐anxiety medicine, rescued anxiety‐like behaviors and excessive self‐grooming in Zfp462^+/? mice. In conclusion, Zfp462 deficiency causes anxiety‐like behaviors with excessive self‐grooming in mice. This provides a novel genetic mouse model for anxiety disorders and a useful tool to determine potential therapeutic targets for anxiety disorders and screen anti‐anxiety drugs.     

Induction of hepatocyte‐like cells from human umbilical cord‐derived mesenchymal stem cells by defined microRNAs

Generating functional hepatocyte‐like cells (HLCs) from mesenchymal stem cells (MSCs) is of great urgency for bio‐artificial liver support system (BALSS). Previously, we obtained HLCs from human umbilical cord‐derived MSCs by overexpressing seven microRNAs (HLC‐7) and characterized their liver functions in vitro and in vivo. Here, we aimed to screen out the optimal miRNA candidates for hepatic differentiation. We sequentially removed individual miRNAs from the pool and examined the effect of transfection with remainder using RT‐PCR, periodic acid—Schiff (PAS) staining and low‐density lipoprotein (LDL) uptake assays and by assessing their function in liver injury models. Surprisingly, miR‐30a and miR‐1290 were dispensable for hepatic differentiation. The remaining five miRNAs (miR‐122, miR‐148a, miR‐424, miR‐542‐5p and miR‐1246) are essential for this process, because omitting any one from the five‐miRNA combination prevented hepatic trans‐differentiation. We found that HLCs trans‐differentiated from five microRNAs (HLC‐5) expressed high level of hepatic markers and functioned similar to hepatocytes. Intravenous transplantation of HLC‐5 into nude mice with CCl₄‐induced fulminant liver failure and acute liver injury not only improved serum parameters and their liver histology, but also improved survival rate of mice in severe hepatic failure. These data indicated that HLC‐5 functioned similar to HLC‐7 in vitro and in vivo, which have been shown to resemble hepatocytes. Instead of using seven‐miRNA combination, a simplified five‐miRNA combination can be used to obtain functional HLCs in only 7 days. Our study demonstrated an optimized and efficient method for generating functional MSC‐derived HLCs that may serve as an attractive cell alternative for BALSS.     

Saitohin Q7R polymorphism is associated with late‐onset Alzheimer's disease susceptibility among caucasian populations: a meta‐analysis

Saitohin (STH) Q7R polymorphism has been reported to influence the individual's susceptibility to Alzheimer's disease (AD); however, conclusions remain controversial. Therefore, we performed this meta‐analysis to explore the association between STH Q7R polymorphism and AD risk. Systematic literature searches were performed in the PubMed, Embase, Cochrane Library and Web of Science for studies published before 31 August 2016. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of the association using a fixed‐ or random‐effects model. Subgroup analyses, Galbraith plot and sensitivity analyses were also performed. All statistical analyses were performed with STATA Version 12.0. A total of 19 case–control studies from 17 publications with 4387 cases and 3972 controls were included in our meta‐analysis. The results showed that the Q7R polymorphism was significantly associated with an increased risk of AD in a recessive model (RR versus QQ+QR, OR = 1.27, 95% CI = 1.01–1.60, P = 0.040). After excluding the four studies not carried out in caucasians, the overall association was unchanged in all comparison models. Further subgroup analyses stratified by the time of AD onset, and the quality of included studies provided statistical evidence of significant increased risk of AD in RR versus QQ+QR model only in late‐onset subjects (OR = 1.56, 95% CI = 1.07–2.26, P = 0.021) and in studies with high quality (OR = 1.37, 95% CI = 1.01–1.86, P = 0.043). This meta‐analysis suggests that the RR genotype in saitohin Q7R polymorphism may be a human‐specific risk factor for AD, especially among late‐onset AD subjects and caucasian populations.