限制性内切酶策略鉴定CRISPR/Cas9介导的Chrm3基因敲除小鼠

CRISPR/Cas9技术是近年发展起来的快速基因编辑技术。通过该技术已对多种生物的基因组进行了编辑。由此产生的基因编辑动物的建系与鉴定是随之而来较为繁琐的工作。单导向RNA(single-guide RNA, sgRNA)靶序列的设计和确定不仅影响后续靶向基因组的效率,还可作为优化鉴定、筛选方法的参考。本研究在选取sgRNA靶序列时,不仅依据软件的评分,还分析了sgRNA靶序列是否含有酶切位点,以便对后续纯合子/杂合子进行鉴定。结果显示,以特异引物扩增的野生型小鼠Chrm3基因片段可被限制性内切酶BanⅡ切为两个片段;而纯合子小鼠“丢失”该酶切位点,其PCR产物不能被切开;杂合子小鼠PCR产物被不完全切开,凝胶电泳结果可见三条带。本研究结果提示该策略可有效简化基因编辑动物建系鉴定工作,提高鉴定效率及改善阳性动物辨识效果。     

Movements of field mice Apodemus agrarius (Pallas) in a suburban mosaic of habitats

Summary Movements of field mice (Apodemus agrarius) were studied using snap traps and coloured bait. The presence of coloured bait was recorded in 35% of field mice captured. Of animals with coloured bait, 60% had moved further than 100 m. The longest distances traversed by field mice exceeded 1000 m. It is suggested that live-trapping on a grid of several hectares is not an adequate method of studying small-mammal movements.     

Circadian rhythms of proliferation events in two mouse carcinomas

We studied the index of DNA synthesis (DNAs) of two cellular carcinomas: the hepatocellular ES12a and the mammary TN60 of mice, throughout one circadian cycle. In the results, we observed that both tumors have circadian rhythms (CRs), but the peaks of DNAs vary. Besides, the mean of DNAs along 24 h shows significative differences, the TN60 has higher values than the ES12a. These observed CR in the DNAs index in both carcinomas mean that, at least in partly, the proliferation of cancer cells can be regulated by endocrine factor as it normally occurs in ordinary cells. The big problem we can find for the chronopharmacology is that it is impossible to know in advance the rate of proliferation of each tumor.     

Female medical physicists: The results of a survey carried out by the International Organization for Medical Physics

IntroductionThe gender composition of the existing medical physicist (MP) workforce around the world is basically unknown. The International Organization for Medical Physics (IOMP) performed a survey in order to investigate the number of MPs in countries around the world and the percentage of women MPs compared to total number of MPs.Materials and methodsA simple online questionnaire prepared as a Google Forms survey asking the country, the total number of MPs, the number of female MPs and finally the gender of the person providing the data was sent in mid-March 2013 to six regional member organizations of IOMP, as well as contact points in many member countries.ResultsSixty-six countries responded to the survey by mid-July 2013. Fifty two percent of those who filled the form were females, the rest males. The total number of MPs was 17,024, of which 28% were female (4807). The median values of percentages of females were 21% in the USA, 47% in Europe, 35% in Asia, 33% in Africa and 24% in Latin America.ConclusionThis is the first international survey that investigates the number and percentage of female MPs around the world. There are European countries that are far away from the target set by European Commission (40%) whereas in countries in the Middle East and Asia, female MPs actually outnumber males. This study is the first step in a more in-depth study that needs to be taken in near future.     

Evidence for mate‐encounter Allee effect in an invasive longhorn beetle (Coleoptera: Cerambycidae)

1. Limited empirical support is available for mate‐encounter Allee effects in invasive insects due to the logistical challenges of studying demographic trends in low‐density populations. 2. Traps baited with pheromone and spruce volatiles were used to monitor the abundance of female Tetropium fuscum F. (Coleoptera: Cerambycidae) at multiple sites in Nova Scotia in 2011 and 2012. Each female was dissected to determine the presence or absence of sperm in its spermatheca (mated or virgin female, respectively). 3. Both male and total T. fuscum abundance declined with increasing distance to the focal point of T. fuscum's invasion. Female mating probability declined with male abundance and with distance from the invasion focus, and mating probabilities were very low at the most peripheral sites. Difficulty in encountering mates may thus contribute to limiting the spread of T. fuscum. 4. The approach outlined here could be integrated into existing surveys of wood borers using traps baited with semiochemicals to improve our understanding of the role of the mate‐encounter Allee effect in invasion dynamics.     

Abnormal behavior,striatal dopamine turnover and opioid peptide gene expression in histamine‐deficient mice

Hypothalamic histaminergic neurons regulate a variety of homeostatic, metabolic and cognitive functions. Recent data have suggested a modulatory role of histamine and histamine receptors in shaping striatal activity and connected the histaminergic system to neuropsychiatric disorders. We characterized exploratory behavior and striatal neurotransmission in mice lacking the histamine producing enzyme histidine decarboxylase (Hdc). The mutant mice showed a distinct behavioral pattern during exploration of novel environment, specifically, increased frequency of rearing seated against the wall, jumping and head/body shakes. This behavioral phenotype was associated with decreased levels of striatal dopamine and serotonin and increased level of dopamine metabolite DOPAC. Gene expression levels of dynorphin and enkephalin, opioids released by medium spiny neurons of striatal direct and indirect pathways respectively, were lower in Hdc mutant mice than in control animals. A low dose of amphetamine led to similar behavioral and biochemical outcomes in both genotypes. Increased striatal dopamine turnover was observed in Hdc KO mice after treatment with dopamine precursor l ‐Dopa. Overall, our study suggests a role for striatal dopamine and opioid peptides in formation of distinct behavioral phenotype of Hdc KO mice.     

Biochanin-A alleviates fibrosis and inflammation in cardiac injury in mice

Biochanin-A (BCA), is an isoflavonoid, exhibits protective effects against various diseases. This study was conducted to observe the effect of BCA on isoprenaline (ISP)-induced cardiac fibrosis and explore the underlying mechanism. The curative effect of BCA was investigated with oral administration for 14 days in ISP-induced cardiac fibrosis in mice. The fibrotic biomarkers, like collagen I and III, were estimated by ELISA. Commercial kits were used to estimate cholesterol, triglycerides, and creatine kinase-myocardial band (CK-MB) levels. The messenger ribonucleic acid (mRNA) expression studies were performed by quantitative real-time polymerase chain reaction. Gelatin zymography was used to study the expression of matrix metalloproteinases-2 (MMP-2). BCA co-administration significantly improved the morphometric parameters; including heart weight, heart weight to body weight, heart weight to tibial length, and lipid profile. BCA treatment showed a reduction in inflammatory cells and collagen deposition as depicted in the histopathology of heart tissues. The enhanced levels of collagen-I, III, and hydroxyproline were significantly decreased by BCA co-treatment, whereas CK-MB level was reduced slightly. BCA co-administration increased the activity of reduced glutathione enzyme, showing the antioxidative effects of BCA. BCA treatment significantly reduced interleukin-6 (Il6) inflammatory cytokine along with partially decreased mRNA expression of fibrotic signaling markers such as natriuretic peptide type B (Nppb), α-smooth muscle actin (Acta2), connective tissue growth factor (Ctgf), transforming growth factor β (Tgfb), small mothers against decapentaplegic homolog-3 (Smad-3). However, BCA did not modify Mmp-2 expression, which was significantly increased by ISP. In conclusion, BCA exerts an antifibrotic effect by modulating lipid profile, enhancing antioxidant enzyme, and reducing collagen content and inflammation.     

Are Robertsonian variations a frequent phenomenon in mouse populations in Eurasia?

We examined the karyotypes of 212 specimens of the house mouse obtained from 44 localities in central and eastern Europe, and several regions of Asia. The Robertsonian chromosome fusion 5.12 was found in a population of Mus musculus musculus in Czechoslovakia. Two large HSRs on chromosome 1 were ascertained in four female mice from western Siberia. In most of the localities under study, the mice possessed a normal karyotype with 40 acrocentric chromosomes.     

竞争性PCR检测MLC_2-糜酶融合基因在转基因小鼠中的组织特异性表达

 用竞争性 Ｐ Ｃ Ｒ 方法定量检测了大鼠肌球蛋白轻链 ２ 启动子（ｍ ｙｏｓｉｎ ｌｉｇｈｔ ｃｈａｉｎ ２ ｐｒｏｍ ｏｔ ｅｒ, Ｍ Ｌ Ｃ２） 糜酶（ｃｈｙｍ ａｓｅ）融合基因在转基因小鼠不同组织中的表达情况,发现 Ｍ Ｌ Ｃ２ ｃｈｙｍ ａｓｅ融合基因在转基因小鼠的心脏中有较高水平的表达,在骨骼肌中表达水平较低,在肾脏中有微弱表达;而在肝脏和肺中未检测到．表明 Ｍ Ｌ Ｃ２ ｃｈｙｍ ａｓｅ 融合基因改变了野生型 ｃｈｙｍ ａｓｅ 在生物体内的表达特性,不仅提高了表达效率,而且赋予了一定的心脏组织特异性,为进一步研究 ｃｈｙｍ ａｓｅ 基因在心脏中的功能奠定了基础．