Theoretical study of NO adsorbed on the surface of TiO<Subscript>2</Subscript> (110) cluster model

The chemisorption properties of N¹⁸O adsorption on TiO₂(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N₂ molecules were at (low) temperature of 230 K, 450 K and (high) temperature of 980 K. This meant that N¹⁸O decomposed and recombined during the process of N₂ desorption after N¹⁸O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO₂(110) cluster model showed that there was clear preference for the Ti-NO orientation.     

基于应用型人才培养的地方高校分子生物学实验教学改革与探索

在高等教育竞争日益激烈的形势下,地方高等院校如何实现学生的特色培养显得尤为重要。分子生物学是生命科学相关学科的主干课程,具有很强的实践性。本文结合当前地方院校分子生物学实验课程开设现状,从教学模式、手段、考核方式等方面进行改革与探索,以期提高地方高校分子生物学实验教学质量及学生的综合素质。     

Role of CD97stalk and CD55 as molecular markers for prognosis and therapy of gastric carcinoma patients

Objectives: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas. Methods: Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55. Results: CD97^stalk was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97^stalk was frequently observed in tumors of stage I and T1 gastric carcinoma patients. The expression of CD97^stalk between Stage I and Stage II, III, IV specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2 T3, T4 specimens was significantly different (P<0.05). There was strong correlation between the distribution patterns of CD97^stalk and CD55 on tumor tissues (r=0.73,P<0.05). Signet ring cell carcinomas frequently contained strong CD97^stalk and CD55-staining. Conclusions: Our results suggest that CD97^stalk is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97^stalk and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients. Project (No. 2004C34010) supported by the Science and Technology Bureau of Zhejiang Province, China     

线粒体DNA标记技术及其在蛛形学研究中的应用

综述线粒体DNA(mtDNA)的特征、线粒体基因组遗传特性认识的改进和mtDNA分子标记技术在蛛形学研究中的应用;并探讨了线粒体DNA标记技术在蜘蛛分子系统学研究和基因组分析中的广泛应用前景.     

广义柏科主要分类群起源时间的推测

通过构建分子钟对广义柏科主要分类群的起源时间进行探讨。采用相对速率检验法分析广义柏科mat K、rbc L进化速率的稳定性，结果显示rbc L的非同义替代速率只在Pinaceae与Taxodiaceae的分类群及柏科北半球的支系(Cupressoideae)之间通过相对速率检验，而Pinaceae与柏科南半球分支(Callitrodeae)之间没有通过相对速率检验。mar K基因的非同义替代速率在Pinaceae与广义柏科的所有分类群之间通过相对速率检验。根据通过相对速率检验的分类群之间的遗传距离和基因进化速率，计算它们发生分歧的时间。据此推测，杉科的主要分类群Taiwanioideae、Athrotaxidoideae、Sequoioideae与其他分支发生分歧的时间均在侏罗纪，支持现存杉科在侏罗纪就已经建立起来的观点；Cupressaceae(s．s．)的两个支系(亚科)发生分歧的时间在124Ma之前，相当于早白垩世早期，可能由于南北古大陆的完全分离，其祖先居群被分隔成两个亚群，随后各自演化为不同的支系。Callitirodeae、Cupressoideae各属发生分歧的时间也均在白垩纪，表明Cupressaceae(s．s．)在白垩纪就已经建立起来。     

Species concepts and biodiversity in Trichoderma and Hypocrea：from aggregate species to species clusters？

Trichoderma/Hypocrea is a genus of soil-borne or wood-decaying fungi containing members important to mankind as producers of industrial enzymes and biocontrol agents against plant pathogens, but also as opportunistic pathogens of immuno-compromised humans. Species identification, while essential in view of the     

Development of a species-specific PCR assay for authentication of Agkistrodon acutus based on mitochondrial cytochrome b gene

BackgroundAgkistrodon acutus, a traditional Chinese medicine, clinically used in the treatment of rheumatism, tumor, and cardiovascular and cerebrovascular diseases. Due to the unique medicinal value and the difficulty of artificial breeding of Agkistrodon acutus, the supply of Agkistrodon acutus on the market exceeds the demand, and a large number of its adulterants are found on the market. In this study, the cytb gene sequences of Agkistrodon acutus and 9 snakes were compared and analyzed, specific primers were designed, and specific PCR methods were established to detect Agkistrodon acutus medicinal samples on the market.ResultsThis method was successfully applied to distinguish the snake from other adulterated species, and tested 18 Agkistrodon acutus samples randomly purchased from six cities. Twelve samples were counterfeit and six were genuine. The standard reference material of Agkistrodon acutus was cloned by molecular cloning and sequencing, and the gene sequence difference with other species was significant. It shows that the region could be used as the fingerprint region of the target species.ConclusionsThe proposed method can be used as a species-specific marker and can be highly distinguished from other adulterated snake species, which is helpful to effectively avoid the problem of false sale of Agkistrodon acutus.How to cite: Yingnuo L, Yanshuang W, Mingcheng Li, et al. Development of a species-specific PCR assay for authentication of Agkistrodon acutus based on mitochondrial cytochrome b gene. Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.07.005     

Academic organizations and new industrial fields: Berkeley and Stanford after the rise of biotechnology

The increasing intertwining of academic and commercial research networks has led to fundamental changes in the organization of modern science. Industry links not only affect the professional dynamics within individual scholarly communities but also affect the position of these communities in their broader academic environment. This paper outlines how industry ties open up opportunities for scientific institution builders to strengthen the legitimacy of their fields of scientific enquiry within this environment. How an academic environment shapes efforts by institution-builders to pursue these opportunities is examined in the context of reorganizations in the life sciences at the University of California at Berkeley and Stanford University following the rise of biotechnology during the 1980s and 1990s. This study also highlights how different models of technology transfer shaped the organizational structures of the expansionist initiatives pushed through at these two universities by molecular biologists with close industry ties.     

铁破锣属的系统位置——ITS(nrDNA)序列证据

对Beesia calthifolia等5种金莲花亚科植物的核糖体DNA中的内转录间隔区(ITS)序列及5．8S rRNA基因的3′端序列进行了测定。这几种金莲花亚科植物的ITS-1的长度范围为225～232 bp,ITS-2 的长度范围为201～217 bp。B．calthifolia的ITS-1(227 bp)和ITS-2(215 bp)的长度及序列均与升麻 属及类叶升麻属植物相近,其5.8S rRNA基因的3′端序列也近乎与升麻属及类叶升麻属植物完全一致 (仅一个碱基缺失的差异),但其在上述几方面均与金莲花属植物相差甚远。以Ranunculus enysii作为 外类群,运用PAUP软件进行的系统发育分析表明:B．calthifolia,Cimicifuga acerina,C．brachycarpa 和Actaea asiatica形成一个单系群,并得到bootstrap分析的极强支持,B．calthifolia位于这一单系群的 基部。这一DNA序列分析结果与来自植物化学、孢粉学和细胞学的研究结果相吻合,更进一步支持铁破锣属是升麻族的自然成员,并可能是升麻族中一个最原始的类群。     

Directed Evolution: A Historical Exploration into an Evolutionary Experimental System of Nanobiotechnology, 1965–2006

This study explores the history of nanotechnology from the perspective of protein engineering, which differs from the history of nanotechnology that has arisen from mechanical and materials engineering; it also demonstrates points of convergence between the two. Focusing on directed evolution—an experimental system of molecular biomimetics that mimics nature as an inspiration for material design—this study follows the emergence of an evolutionary experimental system from the 1960s to the present, by detailing the material culture, practices, and techniques involved. Directed evolution, as an aspect of nanobiotechnology, is also distinct from the dominant biotechnologies of the 20th century. The experimental systems of directed evolution produce new ways of thinking about molecular diversity that could affect concepts concerning both biology and life.