Optimized prime editing efficiently generates heritable mutations in maize

Low efficiency is the main obstacle to using prime editing in maize(Zea mays). Recently, prime-editing efficiency was greatly improved in mammalian cells and rice(Oryza sativa) plants by engineering primeediting guide RNAs(pegRNAs), optimizing the prime editor(PE) protein, and manipulating cellular determinants of prime editing. In this study, we tested PEs optimized via these three strategies in maize. We demonstrated that the ePE5max system, composed of PEmax, epegRNAs(pegRNA-evopreQ. 1), nick...     

Enhanced lovastatin production by solid state fermentation ofMonascus ruber

The purpose of this study was to optimize the solid state cultivation ofMonascus ruber on sterile rice. A single-level-multiple-factor and a single-factor-multiple-level experimental design were employed to determine the optimal medium constituents and to optimize carbon and nitrogen source concentrations for lovastatin production. Simultaneous quantitative analyses of the β-hydroxyacid form and β-hydroxylactone for of lovastatin were performed by the high performance liquid chromatography (HPLC) method with a UV photodiode-array (PDA) detector. The total lovastatin yield (4≈6 mg/g, average of five repeats) was achieved by adding soybean powder, glycerol, sodium nitrate, and acetic acid at optimal composition of the medium increased by almost 2 times the yield observed prior to optimization. The experimental results also indicated that the β-hydroxylactone form of lovastatin (LFL) and the β-hydroxyacid form of lovastatin (AFL) simultaneously existed in solid state cultures ofMonascus ruber, while the latter was the dominant form in the middle-late stage of continued fermentation. These results indicate that optimized culture conditions can be used for industrial production of lovastatin to obtain high yields.     

Effects of different dopant elements on structures,electronic properties,and sensitivity characteristics of nitromethane

In this study, the doped defects in nitromethane crystals were investigated using first-principles calculations for the first time. We introduce dopant atoms in the interstitial sites of the nitromethane lattice, aiming to study the effects of element-doping on the structural properties, electronic properties, and sensitivity characteristics. The obtained results show that doped defects obviously affect the neighboring nitromethane molecules. The modification of electronic properties shows that the band gaps are significantly influenced by doped defects. Partial density of states and population analysis further reveal the mechanism for sensitivity control of nitromethane. It is shown that the new electronic states were introduced in the forbidden bands and the doped defects resulted in charge redistributions in the systems.

Open image in new window

Graphical abstract The valence and conduction band edge positions as well as defect levels of pure and X-doped NM

     

基因调控网络的模块化组织研究

基因调控网络表现的是大量基因受到转录因子的调控而最终转录翻译为蛋白质进而实现生物功能的复杂信息, 是人们理解生物过程和基因功能的重要内容。为了理解基因调控网络中的调控机理, 网络的拓扑结构及其组织方式是极其重要的研究内容之一。它不仅能说明网络的局部特征, 并且能揭示调控网络的构造方法, 同时还能对调控信号通路进行全面系统的分析。调控网络可分为4层结构: 调控元件、Motif、模块和整个网络。当前, 这种层次结构受到人们越来越多的认可。文中重点讨论motif和模块两层, 比较分析了近年来对网络组织结构的多方面研究内容, 阐述了各个研究结果与结论具有的生物学意义, 并指出了其中存在的问题。在此基础上, 文中还针对这些问题提出了可能存在的研究方向, 并展望了基因调控网络模块化组织的研究前景。     

致病疫霉在中国云南的马铃薯田间形成卵孢子*

由致病疫霉Phytophthora infestans (Mont.)de Bary引起的马铃薯和番茄晚疫病是世界性的作物病害,每年均造成巨大的经济损失和社会影响。致病疫霉是异宗配合的卵菌,有两个已知交配型A1和A2,两个相对交配型互作时可进行有性生殖产生卵孢子( Gallegly & Galindo,1958)。过去许多年一直认为致病疫霉在除墨西哥以外的国家中只存在A1交配型,通过产生孢子囊进行无性繁殖。近年来,由于致病疫霉新致病群体的产生以及全球范围的迁移和替代,A2交配型菌株先后在欧洲、美洲、亚洲和非洲的许多国家被发现。A1、A2两种交配型菌株的同时存在,增…     

池蝶蚌胚胎发育与繁殖季节性腺的观察

以池蝶蚌(Hyriopsis schlegeli)育儿囊中单细胞胚胎为材料,通过连续观察、人工体外培养等方法,对繁殖季节池蝶蚌的生殖腺特性、生殖细胞形态、胚胎发育过程等进行了观察.结果表明,年满4冬龄池蝶蚌卵巢的相对怀卵量为(2.25±1.09)×103粒/g,绝对怀卵量为1.93×104～1.03 × 105粒;性腺指数为24.09%±0.33%;在体外用自制培养液培养的胚胎,部分能正常分裂发育至桑椹期,其胚胎发育过程经历了4个时期,即卵裂期、囊胚期、原肠期、钩介幼虫期.在18～23℃的水温下,胚胎发育历时约12 d;胚胎发育的最适水温为20～30℃.此外,通过池蝶蚌外鳃的特征可初步判断胚胎发育的时期.研究结果可为池蝶蚌人工繁殖、新品种培育及种质资源保护等提供理论依据.     

YB-1与肿瘤发生及治疗

Y-box结合蛋白(Y-box binding protein,YB)是一类广泛存在于从低等到高等多种生物中的蛋白质家族,在体内行使多种生物学功能.大量研究表明,YB-1作为该家族成员之一,与许多重要的生物大分子存在密切联系,并对细胞、组织和机体的生理机能产生重大影响.更为重要的是,YB-1在多种疾病,尤其是恶性肿瘤的发生和发展中也起到十分关键的作用,对癌细胞表型的维持及肿瘤多药耐药性(MDR)的产生具有全方位的影响.以YB-1为作用靶点的新型肿瘤治疗策略可望有效控制癌症患者病情恶化,改善耐药状况.现就对YB-1与肿瘤发生和发展之间关系的研究进展,以及针对YB-1治疗策略的制定作一评述和展望.     

Cancer Incidence among Adolescents and Young Adults in Urban Shanghai, 1973-2005

Background

Lack of cancer incidence information for adolescents and young adults led us to describe incidence trends within the young population of 15 to 49 year-olds in urban Shanghai between 1973 and 2005.

Methods

During 1973 to 2005, data on 43,009 (45.8%) male and 50,828 (54.2%) female cancer cases aged 15–49 years from the Shanghai Cancer Registry were analyzed. Five-year age-specific rates, world age-standardized rates, percent change (PC), and annual percent change (APC) were calculated using annual data on population size and its estimated age structure.

Results

During the 33-year study period, overall cancer incidence of adolescents and young adults among males marginally decreased by 0.5% per year (P<0.05). However, overall cancer incidence for females slightly increased by 0.8% per year (P<0.05). The leading cancer for males in rank were liver, stomach, lung, colorectal, and nasopharyngeal cancers and for females were breast, stomach, colorectal, thyroid, and ovarian cancers. Among specific sites, incidence rates significantly decreased for cancers of the esophagus, stomach, and liver in both sexes. In contrast, incidence rates significantly increased for kidney cancers, non-Hodgkin lymphoma, and brain and nervous system tumors in both sexes and increased for breast and ovarian cancers among females.

Conclusions

Overall cancer incidence rates of adolescents and young adults decreased in males whereas they increased in females. Our findings suggest the importance of further epidemiology and etiologic studies to further elucidate factors contributing to the cancer incidence trends of adolescents and young adults in China.     

葛仙米室内规模化培养、群体显微结构及营养成分分析

以葛仙米为材料开展室内规模化培养,在15个月的培养期间,每月可产鲜藻38.3~293.7 kg,每立方米的培养体积葛仙米每月产量波动在9.58~77.45 kg,高温明显降低月产量。在葛仙米的表层和内部的显微结构明显不同,藻丝的长短、排列存在明显的差异。同时以人工培养的葛仙米为材料,测定了其生化组成;结果表明:人工培养的葛仙米含16种氨基酸,蛋白质含量为29.69%;脂肪的含量为0.78%,远低于野生葛仙米中脂肪的含量;维生素的含量较低;砷、铅、汞、镉4种重金属元素含量较低,其含量符合国家食品卫生标准。