简便、快速提取高质量的RNA分子

MethodsforHandy,RapidIsolationofHighQualityRNAbyGuanadiumThioeyauateDuJianYuanYanhuaMaShenglinDongZhiwei(BeijingInstituteforCancerResearchBeijing100034)硫氰胍是一种有效的蛋白变性剂。早在1979年,Chirgwin等就利用氯化铯／硫氰胍超离心技术成功地从RNA酶富集的胰脏组织中提取出未降解的RNA分子[2],从而使它成为抑制RNA酶的首选药物并得到广泛使用,但受到超速离心设备的限制。1983年,Cathala报道了氯化锂／硫氰胍RNA提取法[1]。该方法操作简便,获得的RNA质量很高,但所需时间较长。为了能在短时间内更快…     

双功能抗体介导的胃癌杀伤效应

将诱变的αＣＤ３杂交瘤（ＴＫ~－）与ＰＤ４杂交瘤（ＨＧＰＲＴ~－）融合,获得分泌双功能抗体（ＢｓＡｂ）的四体杂交瘤Ｃ３．ＢｓＡｂＣ３可分别与ＣＤ３分子及胃癌相关抗原Ｐ４０反应．体外杀伤试验证实,当效靶比为４０：１,ＢｓＡｂＣ３浓度为１ｍｇ／Ｌ时,其杀伤效应可达７７．６％．该杀伤效应具有明显的特异性,仅Ｐ４０阳性表达的靶细胞可被溶解,体内杀伤试验证实,裸鼠接种胃癌细胞后５ｄ,以ＢｓＡｂＣ３活化的外周血淋巴细胞（ＰＢＬｓ）经局部皮下注射处理,可使移植胃癌完全消退（５／５）．这一明显的治疗作用可能与局部注射途径有关,可供临床应用参考．     

Changes of plant community composition instead of soil nutrient status drive the legacy effects of historical nitrogen deposition on plant community N:P stoichiometry

Plant and Soil - Uncovering the importance of soil and plant characteristics in driving the legacy effects of nitrogen (N) deposition on plant community nutrient stoichiometry would improve our...     

植物叶绿体分裂的分子机制

叶绿体是植物细胞内一种重要的细胞器．它不仅是光合作用的场所,还是其它多种中间代谢的场所．叶绿体起源于蓝细菌,与其原核祖先类似,通过二分裂方式进行增殖．最近的研究表明,叶绿体的分裂装置包含原核起源和真核起源的蛋白质,它们在叶绿体的内膜内侧和外膜外侧协同作用以完成叶绿体的分裂．在过去十几年里,包括丝状温度敏感蛋白Z（FtsZ）、Min系统蛋白、质体分裂蛋白（PDV）和ARC蛋白等在内的多个叶绿体分裂相关组分被分离鉴定．本文简要介绍了叶绿体分裂装置各成员的发现、叶绿体被膜的收缩和叶绿体分裂位点的选择机制．另外,植物发育过程中叶绿体分裂可能受到细胞的控制,但目前对细胞如何调控叶绿体分裂知之甚少．本文对该领域的最新研究进展也进行了综述．     

一株高产淀粉绿藻——标志链带藻在废水中的培养及对氮磷的去除

为了研究标志链带藻(Desmodesmus insignis strain JNU24)在不同Na NO3浓度和不同废水浓度培养下的生长与代谢产物积累状况,评估标志链带藻对废水的处理能力,本研究利用柱状光反应器对标志链带藻进行培养,分别对4种Na NO3浓度的BG-11培养基和4种废水浓度培养下藻细胞的生物量、蛋白质含量、碳水化合物含量和淀粉含量进行了测定。结果显示,在BG-11培养基中,氮浓度为9.0 mmol/L时,藻细胞生物质浓度最高,达6.23 g/L;在废水培养下,未稀释的原废水实验组,其藻细胞生物质浓度最高,达10.31 g/L;75%废水培养下,藻细胞的淀粉含量最高(达50.9%),单位体积藻细胞淀粉含量和产率分别为4.86 g/L和405 mg·L~(-1)·d~(-1),且显著高于不同浓度Na NO3的BG-11培养基组。本研究还测定了标志链带藻对废水中氮、磷的去除效率,结果显示不同浓度废水培养下,氮、磷的去除效率最高可达90.8%和98.7%。基于柱状反应器中的最佳培养效果,以9.0 mmol/L Na NO3的BG-11培养基和75%废水于3.0 cm光径平板光生物反应器中进行室内扩大培养,结果显示在75%废水培养下,藻细胞生物质浓度达9.75 g/L,淀粉单位体积含量和产率分别达到4.75 g/L和230 mg·L~(-1)·d~(-1),且为9.0 mmol/L Na NO3的BG-11培养基培养的3倍。通过沉降特性分析发现,藻细胞收获90 min后均完全沉降,具有较强的沉降性能。本研究标志链带藻能够耐受废水中较高的氮、磷浓度,且对废水中氮、磷有显著的去除作用;该藻能利用废水中的营养成分积累较高的生物量和淀粉含量并且藻细胞能快速沉降,具有极高的经济价值和应用价值,是一株淀粉生产能力较高和废水处理能力较强的极具开发潜力的藻株。     

Multiplex gene precise editing and large DNA fragment deletion by the CRISPR-Cas9-TRAMA system in edible mushroom Cordyceps militaris

The medicinal mushroom Cordyceps militaris contains abundant valuable bioactive ingredients that have attracted a great deal of attention in the pharmaceutical and cosmetic industries. However, the development of this valuable mushroom faces the obstacle of lacking powerful genomic engineering tools. Here, by excavating the endogenous tRNA-processed element, introducing the extrachromosomal plasmid and alongside with homologous template, we develop a marker-free CRISPR-Cas9-TRAMA genomic editing system to achieve the multiplex gene precise editing and large synthetic cluster deletion in C. militaris. We further operated editing in the synthetases of cordycepin and ergothioneine to demonstrate the application of Cas9-TRAMA system in protein modification, promoter strength evaluation and 10 kb metabolic synthetic cluster deletion. The Cas9-TRAMA system provides a scalable method for excavating the valuable metabolic resource of medicinal mushrooms and constructing a mystical cellular pathway to elucidate the complex cell behaviours of the edible mushroom.     

Retracted: Prelamin A overexpression promotes detrusor calcification/aging in urinary incontinence via prelamin A accumulation

Urinary incontinence (UI) is known as a distressing condition particularly among older adults, and negatively associated with health-related quality of life in both males and females. Prelamin A accumulation has been found in all progeroid laminopathies and is obviously linked to cell and organism aging. Therefore, this study was expected to investigate the effect of prelamin A on detrusor on UI. Prelamin A expression in clinical and animal samples was detected. To investigate the degree of prelamin A accumulation and detrusor calcification/aging, the detrusor cells were subcultured separately into low and high passage. The low-passage subculture cells were treated with transfection of overexpressed prelamin A plasmid, and transfection of overexpressed prelamin A plasmid and application of farnesyl transferase inhibitor (FTIs) H-9279, respectively. Zmpste24, Icmt and lamin A/C expression were detected to explore how prelamin A affected detrusor calcification/aging. Prelamin A was overexpressed in aged detrusor cells, indicating prelamin A expression was positively related to the age of subjects. The degree of prelamin A accumulation and detrusor calcification/aging was higher in aged rats and high passage subculture cells. Zmpste24, Icmt and lamin A/C were poorly expressed in cells transfected with overexpressed prelamin A, as well as cell proliferation activity decreased and calcium deposition and apoptotic rate increased. Furthermore, we also found that the effect of overexpressed prelamin A was lost when cells were treated with H-9279. These findings provide evidence that prelamin A overexpression impairs degradation of its farnesylated form, thus causing prelamin A accumulation which induces detrusor calcification/aging in UI.     

四川南充市白头鹎的繁殖习性及雏鸟的生长发育

2005年3~8月对南充市的白头鹎(Pycnonotus sinensis)的繁殖习性进行了观察,研究了其雏鸟生长发育模式。结果表明,白头鹎于3月底开始营巢,营巢期(6±1)d,4月初产卵,一般为(3.50±0.50)枚,孵卵期(11±1)d,巢内育雏(13±1)d,雏鸟外部器官的形态学参数用Logistic曲线方程拟合,拟合度高,体长、翼长及10日龄前体重等生长曲线均呈“S”型。     

Performance of the Plusoptix A09 Photoscreener in Detecting Amblyopia Risk Factors in Chinese Children Attending an Eye Clinic

Purpose

To assess the accuracy of the Plusoptix A09 photoscreener in detecting amblyopia risk factors in children and determine referral criteria when using Plusoptix A09 for a large-scale vision screening.

Methods

Pediatric patients attending our eye clinic underwent a comprehensive ophthalmic examination that included photorefraction, orthoptic examination, anterior segment assessment, fundus examination and cycloplegic retinoscopy. The measurements were collected for statistical analyses.

Results

One hundred and seventy-eight children (mean age ± SD: 6.2±2.4 years, range: 2.2 to 14.1 years) were included in the study. The mean spherical equivalent (SE) obtained using Plusoptix A09 (P_SE) was 0.57 D lower than that obtained from cycloplegic retinoscopy (CR_SE) (P = 0.00). However, there was no statistically significant difference of Jackson cross cylinder J₀ and J₄₅ between Plusoptix A09 (P_J) and cycloplegic retinoscopy (CR_J) (P = 0.14, P = 0.26). The relationship of SE obtained from Plusoptix A09 and SE obtained from cycloplegic retinoscopy was presented as the equation: CR_SE = 0.358 + 0.776 P_SE + 0.064 P_SE ² + 0.011 P_SE ³. Based on the Receiver Operating Characteristic (ROC) curve, the Plusoptix A09 had an overall sensitivity of 94.9% and specificity of 67.5% for detecting refractive amblyopia risk factors. The sensitivity and specificity of the Plusoptix A09 for detection of strabismus were 40.7% and 98.3%, respectively; detection of amblyopia and/or strabismus was 84.7% and 63.2%, respectively.

Conclusions

The Plusoptix A09 photoscreener underestimated hyperopia and overestimated myopia according to SE when compared with cycloplegic retinoscopy. The accuracy of the Plusoptix A09 in detecting amblyopia risk factors in children could be improved by the regression equation and optimized criteria for refractive amblyopia risk factors developed in the present study. Moreover, the Plusoptix A09 photoscreener is not suitable for a large-scale strabismus screening when it is applied solely.     

Climatic Factors Drive Population Divergence and Demography: Insights Based on the Phylogeography of a Riparian Plant Species Endemic to the Hengduan Mountains and Adjacent Regions

Quaternary climatic factors have played a significant role in population divergence and demography. Here we investigated the phylogeography of Osteomeles schwerinae, a dominant riparian plant species of the hot/warm-dry river valleys of the Hengduan Mountains (HDM), Qinling Mountains (QLM) and Yunnan-Guizhou Plateau (YGP). Three chloroplast DNA (cpDNA) regions (trnD-trnT, psbD-trnT, petL-psbE), one single copy nuclear gene (glyceraldehyde 3-phosphate dehydrogenase; G3pdh), and climatic data during the Last Interglacial (LIG; c. 120–140 ka), Last Glacial Maximum (LGM; c. 21 ka), and Current (c. 1950–2000) periods were used in this study. Six cpDNA haplotypes and 15 nuclear DNA (nDNA) haplotypes were identified in the 40 populations of O. schwerinae. Spatial Analysis of Molecular Variance, median-joining networks, and Bayesian phylogenetic trees based on the cpDNA and nDNA datasets, all suggested population divergence between the QLM and HDM-YGP regions. Our climatic analysis identified significant heterogeneity of the climatic factors in the QLM and HDM-YGP regions during the aforementioned three periods. The divergence times based on cpDNA and nDNA haplotypes were estimated to be 466.4–159.4 ka and 315.8–160.3 ka, respectively, which coincide with the time of the weakening of the Asian monsoons in these regions. In addition, unimodal pairwise mismatch distribution curves, expansion times, and Ecological Niche Modeling suggested a history of population expansion (rather than contraction) during the last glaciation. Interestingly, the expansion times were found being well consistent with the intensification of the Asian monsoons during this period. We inferred that the divergence between the two main lineages is probably caused by disruption of more continuous distribution because of weakening of monsoons/less precipitation, whilst subsequent intensification of the Asian monsoons during the last glaciation facilitated the expansion of O. schwerinae populations.