一株可裂解耐黏菌素大肠杆菌噬菌体的分离鉴定及全基因组分析

为研究耐黏菌素大肠杆菌的噬菌体治疗方法,本研究以耐黏菌素大肠杆菌为宿主菌,采用双层琼脂平板法从山东烟台某养鸡场污水样中分离纯化得到裂解性噬菌体SDYTW1-F1-2-2。通过透射电镜观察,最佳感染复数,一步生长曲线,温度稳定性,酸碱度稳定性等生物学特性测定,并对其进行全基因组测序分析。结果表明：1）噬菌体SDYTW1-F1-2-2噬菌斑呈现透亮,外周无晕圈,形态学观察显示其具有可伸缩性尾鞘。2）生物学特性分析表明,噬菌体最佳感染复数为0.1,潜伏期为50 min,爆发期为40 min,爆发量为（331±9）PFU/cell。在温度4～40℃,pH为4～12的环境下,噬菌体活性较为稳定。3）通过噬菌体全基因组测序及核酸类型鉴定显示,该噬菌体基因组全长为74 752 bp,双链DNA,GC含量42.1%。在噬菌体基因组中共鉴定出121个编码蛋白（CDS）,包括结构组成、DNA代谢与复制和包装以及细菌裂解相关的功能基因,发现一个tRNA基因,且未检测到如stx-1等致病性基因和mcr-1等耐药基因相关的基因。综上,噬菌体SDYTW1-F1-2-2裂解谱较宽,具有良好的酸碱性、热稳定性以及安全...     

罐藏专用黄桃新品种‘皖83’

 ‘皖83’是从‘佛雷德里克’ ( Frederic, NJC83) 的营养系变异中选育出的罐藏专用黄桃新品种。成熟期比对照品种提早10 d, 树势中庸, 平均单果质量141.2 g, 果肉金黄, 不溶质, 果皮及果核处无红色素, 味甜酸适中, 品质优, 早果, 丰产, 适应性强, 果实加工后果肉金黄色, 有光泽, 香味浓。     

Functions of wild stathmin 1 and the C terminal mutant

AIM: To illustrate the effects of overexpression of stathmin 1 on melanocyte growth and the relationship between C terminal motif and stathmin 1 function.METHODS: The overexpression vector and C terminal mutant coding vector were constructed. The vectors were transfected into melanocytes by Lipofectamine 2000. MTT and FCM were used to inspect the cell growth, Western blotting was a tool in caspase-3 measurement, and spectrophotography was used to detect the melanin products and tyrosinase activity.RESULTS: The vectors of overexpression and mutation were constructed and transfected into melanocytes successfully. Both of them inhibited the melanocyte growth, induced apoptosis, and decreased the melanin products and tyrosinase activity.CONCLUSION: Overexpression of stathmin 1 inhibits melanocyte growth, melanin products and tyrosinase activity. The change of C terminal motif could not affect the role of stathmin 1 in melanocyte markedly.     

Generation of insulin-producing cells from PDX1 and NKX6.1 gene-modified bone marrow mesenchymal stem cells

AIM: To differentiate bone marrow mesenchymal stem cells (BMSCs) into functional insulin-producing cells to produce sufficient pancreatic islet cells for transplantation. METHODS: Recombinant adenovirus vectors carrying PDX1 and NKX6.1 genes were constructed and the bone marrow mesenchymal stem cells were infected by the recombinant adenovirus combined with several cytokines for differentiation. The expressions of PDX1, NKX6.1 and insulin and C-peptide in the differentiated bone marrow mesenchymal stem cells were detected by RT-PCR and Western blotting. After the differentiated bone marrow mesenchymal stem cells were transplanted into subrenal capsule of diabetic mice, cell morphology of the grafts as well as their secretion of insulin and C-peptide were detected. Besides, regulating capacities of grafts on the blood glucose level of the diabetic mice were also detected. RESULTS: BMSCs induced by recombinant adenovirus (pAdxsi-CMV-PDX1/CMV-NKX6.1) and several cytokines showed positive dithizone staining and the expressions of β-cell related molecule such as insulin and glucose transporter 2 were detected by RT-PCR, which showed a sustaining and stable expression. The similar results were showed by Western blotting, immunohistochemical staining and indirect immunofluorescence. The insulin secretions in the cells stimulated with glucose at concentrations of 5.5 and 25 mmol/L in the experimental group were (1 240.4±109.3) mU/L and (3 539.8±245.1) mU/L, respectively, and were significantly higher than those in control group. Moreover, transplantation of the cells to STZ mice in treatment group made serum glucose recover to normal level. CONCLUSION: PDX1 and NKX6.1 gene-modified bone marrow mesenchymal stem cells differentiate into insulin-producing cells in vitro. When these cells transplanted into STZ induced diabetic mice, their serum glucose could return to the normal level and they could live well. Thus this is a promising method for diabetes treatment.     

不同茄子品种幼苗耐热性研究

以45 ℃/36 ℃（昼/夜）的温度对4个茄子品种进行胁迫处理,研究了高温胁迫对茄子的热害指数、电解质渗透率、SOD活性、MDA含量及叶绿素荧光参数的影响。结果表明,高温处理后,茄子热害指数、电解质渗透率及MDA含量显著上升,耐热品种上升幅度低于不耐热品种;SOD活性显著降低,恢复2 d后耐热品种06-E417和紫妃1号的SOD活性比处理前上升了20.3 %和20.7 %,不耐热品种则没有表现这种趋势。高温胁迫后,茄子Fv/Fm、Fv/Fo、ΦPSⅡ、qP、ETR及Fv’/Fm’均显著降低,耐热品种降低的幅度低于不耐热品种,表明在高温胁迫后耐热品种具有较高的光系统Ⅱ活性。     

不同贮前热处理对青种枇杷果实贮藏效应的研究

通过采用不同的贮前热处理温度和时间组合,研究白沙枇杷青种在低温条件下的贮藏的内外品质的变化.结果表明:3种贮前热处理中,B处理(45℃热水处理10 min+低温(6±1℃))的效果最好,不仅青种枇杷果实的失重率和腐烂率低;而且贮藏到30 d时,枇杷果实的固酸比最高,较好保持了果实的风味.     

蝴蝶兰种子无菌播种诱导增殖原球茎试验研究

利用不同激素浓度及添加物对蝴蝶兰未成熟胚有效原球茎进行诱导研究.结果表明:进行无菌播种采收未开裂的果荚比已开裂的要有利的多,采摘最佳时间为授粉后120 d;原球茎增殖效果最佳的激素组合是BA 3.0+NAA 0.2;200 mL/L椰乳对蝴蝶兰PLB增殖的影响效果最好,其次为香蕉和马铃薯.     

水芋体细胞胚胎发生及植株再生休系的建立

以水芋幼叶为外植体,应用均匀设计法筛选其最适合的胚性愈伤组织及胚性细胞复合体诱导、体细胞胚胎发育及植株再生的培养基,建立了水芋体细胞胚胎发生体系.对不同阶段培养材料的形态结构及超微结构的观察证明了水芋体细胞胚胎的发育过程.结果表明:水芋叶片胚性愈伤组织及胚性细胞复合体诱导最适宜培养基为:LS+6-BA 0.5 mg/L+2,4-D 2.0mg/L,诱导率为98.5%;体胚发育及植株再生最适宜的培养基为:LS+6-BA1.0 mg/L+NAA0.5mg/L+IAA 1.0 mg/L,体胚萌发率为96%,萌发的体胚在发育培养基上继续培养25 d后全部发育成完整植株.