沼泽红假单胞菌生物合成银纳米粒子及其抗菌作用

近年来,利用沼泽红假单胞菌合成银纳米粒子作为一种可靠和环境友好的方法出现。主要利用沼泽红假单胞菌的细胞滤液来还原银离子。制备的纳米粒子用紫外可见光谱(UV-vis)、X射线衍射光谱(XRD)和透射电镜(TEM)进行表征。含有银粒子溶液的UV-vis光谱显示在420 nm-460 nm处出现银纳米粒子的吸收峰。TEM图像表明所形成的银纳米粒子的粒径范围为5 nm-20 nm。纳米粒子的XRD图谱证明产物为金属银。所制备的银纳米粒子对大肠杆菌和金黄色葡萄球菌作抑菌性试验。     

人脐血CD133细胞的分离及其体外扩增的研究

目的:探讨免疫磁性纳米粒子分离人脐血CD133细胞的方法,了解分离出的CD133细胞在体外短期培养中的变化及其在体外扩增的可能性。方法:通过化学沉淀法制备具有超顺磁性的r-Fe_2O_3纳米粒子,在其表面包裹具有生物亲合性的二氧化硅,并在其表面通过化学修饰使其成为生物功能化的磁性纳米粒子。再通过一定的化学连接方法将单克隆抗体CD133连接到生物功能化的磁性纳米粒子表面使其成为免疫磁性纳米粒子,然后利用自制的免疫磁性纳米粒子从单个核细胞中分离出CD133细胞,并分别对单个核细胞和CD133细胞在体外短期培养中的动态变化进行了初步观察和比较。结果:经免疫磁性纳米粒子分离的脐血中CD133细胞平均数为(5±1．4)×10~7/ml,占单个核细胞数的(3±0．3)%;单个核细胞(对照组)和CD133细胞(实验组)分别进行红、粒系集落扩增培养14天、21天,实验组中两种造血祖细胞集落扩增倍数都明显高于对照组(P＜0．01)。结论:使用自制的免疫磁性纳米粒子能较好的分离脐血中的CD133细胞,分离与纯化出来的CD133细胞不仅细胞活力不受影响,而且与单个核细胞相比具有更强的增殖能力。     

一株胞内合成纳米磁性颗粒菌株的筛选及鉴定

【目的】从聊城东昌湖湖水中分离纯化出一株可合成纳米磁性颗粒的菌株,将其命名为TZ-1。【方法】对该菌株进行形态学研究、分子生物学鉴定,将TZ-1菌株合成的纳米磁性颗粒进行提取纯化,并对菌体和纳米磁性颗粒进行透射电镜(transmission electron microscope,TEM)观察、扫描电镜(Scanning electron microscope,SEM)元素分析,对纳米磁性颗粒进行X射线衍射(X-ray diffraction,XRD)分析。【结果】经鉴定TZ-1属于伯克霍尔德氏菌属(Burkholderia sp.)。透射电镜下菌体为杆状,易聚集,有明显的单生鞭毛,有荚膜,在TEM下观察菌体内部有两种电子致密颗粒,较小颗粒分布在菌体细胞膜附近,近似多边形,大小约为60 nm,较大颗粒分布在菌体内部,大小约为180 nm,表面有膜包裹。扫描电镜(SEM)下细胞为杆状,大小与TEM下测量结果一致。SEM下对磁性颗粒进行元素分析,主要为Fe、P、O。根据TEM、SEM、XRD结果推测菌体可合成纳米磁性颗粒。【结论】分离纯化出的菌株TZ-1可合成纳米磁性颗粒,磁性颗粒X射线衍射结果分析知TZ-1合成的纳米磁性颗粒为单斜晶体,主要成分为Fe3(PO4)2·8H2O和Fe3O4。     

难溶性药用纳米微粒的原子力显微检测

建立用原子力显微镜(AFM)检测难溶性药用纳米微粒的方法。将纳米微粒配成一定浓度的悬浮液,以新鲜裂解的云母表面作为样品载体,在室温下用AFM的接触模式成像,用粒度分析软件进行粒度分析。以此方法对两种微粒(活性炭及氧化锌纳米微粒)进行了成像和测量,同时对两种样品进行透射电镜(TEM)观察。AFM检测结果显示,纳米活性炭微粒形态近似球形,表面较平滑,平均直径为(299±187)nm;纳米氧化锌微粒呈球形,平均直径(50±20)nm,与TEM检测结果具有较高一致性。该法简便可靠。     

纳米级Fe3O4磁性粒子与人肝癌细胞HepG-2及人正常肝细胞L02作用的生物学行为的实验研究

目的:对纳米级Fe3O4磁性粒子与人肝癌细胞HepG-2及人正常肝细胞L02作用的生物学行为进行实验研究。方法:通过化学沉淀法制备粒径为10nm左右的纳米级Fe3O4磁性粒子,观察其表征;将不同浓度纳米级Fe3O4粒子加入培养液分别与HepG-2混合培养检测凋亡坏死率;将相同浓度粒子分别与HepG-2和L02混合培养,对两者作用的差异进行动态观察比较。结果:纳米级Fe3O4磁性粒子能在肝癌细胞HepG-2细胞内稳定存在72小时以上,有良好的生物相容性;透射电镜观察到Fe3O4磁性粒子主要分布于细胞的溶酶体及吞噬泡内。共培养1小时后即有较多的纳米磁性粒子进入HepG-2内,而3小时后才见L02细胞内有少量的磁性粒子进入。结论:此实验结果为磁性纳米粒子与肿瘤细胞微观结构的作用提供了有意义的实验数据,并可能对应用磁性纳米粒子治疗恶性肿瘤提供有价值的依据。     

基于L-半胱氨酸修饰的Fe3O4@TiO2复合纳米颗粒体外光动力疗法灭活HL60细胞的试验研究

本文采用共沉淀法制备了L-半胱氨酸(L-Cys)修饰的Fe3O4包裹TiO2(Fe3O4@TiO2/L-Cys)复合纳米粒子。通过透射电子显微镜(TEM),X射线衍射(XRD)和傅立叶变换红外光谱仪(FTIR)对复合纳米粒子进行了表征,并讨论了复合纳米粒子对HL60细胞体外光动力疗法(PDT)灭活的影响。并对其PDT灭活机制进行了初步探索。试验表明,Fe3O4@TiO2/L-Cys复合纳米粒子分散性高,生物相容性好,对细胞的暗毒性更低,并可以有效增强靶向性,提高PDT灭活效率,在410nm波长的光激发下,光照剂量为18J/cm^2的情况下,当TiO2与Fe3O4的比例为1∶3时,整体PDT效率最高。PDT灭活效率可达69.36%。     

基于超声驱动磁性纳米粒子的肿瘤细胞灭杀

磁性纳米粒子肿瘤热疗技术是目前国际上肿瘤研究的热点.本文提出了一种基于超声驱动磁性纳米粒子(UDMNP)运动进行肿瘤细胞灭杀的新技术,实现磁性纳米粒子的肿瘤治疗.系统研究了肝癌肿瘤细胞HepG2的治疗效果,在一定超声频率下,改变超声功率和超声作用时间,UDMNP具有明显灭杀效果.实验结果显示,较小超声功率下,肿瘤细胞损伤较小,随着超声功率增加,UDMNP对肿瘤细胞表现出明显的灭杀作用.同时,随着作用时间增加,同一超声功率驱动下UDMNP对细胞的灭杀效果也明显提高,光学显微镜观察到细胞形态发生明显变化.本文提出的UDMNP肿瘤细胞灭杀方法的显著优势是减少了化学毒性和有害辐射,是一种物理性机械损伤技术,对促进磁性纳米粒子的临床医学应用有重要意义.     

核-壳型磁性纳米微球的制备及在核酸提取中的应用

目的:改进传统的溶胶-凝胶方法而制备得表面包裹SiOZ的核-壳型磁性纳米微球,然后将表面连有链霉亲和素的磁性纳米微球应用于生物样品中核酸的分离.方法:用透射电子显微镜(TEM)、红外光谱(FTIR),X射线衍射仪(XRD)和磁强计(VSM)对得到的纳米微球进行表征,最后用电泳验证核酸.结果:表明制备得到的磁性纳米微球表面包裹Si02,粒径均匀,分散性良好,并且具有超顺磁性和较大的比饱和磁化强度.电泳结果表明磁性微球可以很好地从细胞悬液、组织、血液等样品中分离得到高质量的核酸.结论:该方法简便快速有效,其过程不需要使用任何有毒溶剂,操作简单.     

基于CdSe掺杂锐钛矿TiO_2的可见光体外灭活HL60细胞实验研究

用超声驱动方法合成了CdSe/TiO_2复合纳米粒子,并通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、紫外可见光(UV-Vis)吸收光谱和荧光(FS)光谱对CdSe/TiO_2复合纳米粒子进行表征。使用CCK-8法测定CdSe/TiO_2对白血病细胞的可见光光催化活性并通过SEM研究HL60细胞的表面超微结构形态。实验结果表明,用CdSe/TiO_2复合纳米粒子处理的组中观察到明显的HL60细胞生长抑制,并且HL60细胞在CdSe掺杂TiO_2复合纳米粒子作用下的PDT效率显著高于TiO_2,表明可以通过CdSe的修饰有效增强TiO_2的可见光光催化活性。此外,CdSe/TiO_2在可见光辐照下在4μg/m L的终值浓度下显示非常高的光动力效率,达76%。荧光光谱分析表明,CdSe/TiO_2复合纳米粒子可能通过分离光生空穴电子对提高此复合纳米粒子的光催化活性,从而提高CdSe/TiO_2对HL60细胞的PDT灭活效率。     

以四甲基氢氧化铵为溶剂的磁性纤维素微球制备、表征及应用

以微晶纤维素和磁性Fe_3O_4纳米粒子为原料,四甲基氢氧化铵溶液为溶剂,通过乳化法制备了磁性纤维素微球。利用扫描电微镜、傅里叶变换红外光谱仪、X线衍射仪、振动样品磁强度计、比表面和孔径分析仪对磁性纤维素微球进行分析表征,结果表明磁性纤维素微球确为纤维素包裹Fe_3O_4纳米粒子形成,且表面粗糙,粒径约200 nm,比表面积13.6 m~2/g,表面微孔体积为0.5 cm~3/g,磁强度为2.0×10~(-3) T/g。磁性纤维素微球染料吸附试验表明,在pH 4～8时其对亚甲基蓝的去除率最大,达到70%以上。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.