核酸适配体在病原微生物检测中的应用研究进展

核酸适配体是一段单链寡核苷酸分子,主要通过指数富集配体系统进化技术获得.核酸适配体可以通过其独特的三维结构高选择性地与目标靶点结合,具有与抗原-抗体反应相类似的高亲和性、高特异性.核酸适配体由于具有分子量小、无免疫原性、合成成本低、可通过化学修饰获得高稳定性等区别于蛋白质抗体的优点,成为病原微生物检测的研究开发热点.核...     

纳米材料在大肠癌治疗中的应用进展

大肠癌是目前世界范围内导致癌症相关死亡的重要因素之一,目前治疗以传统的手术、化疗及放疗为主,但效果不佳.近年来,随着纳米材料在生物医学领域的深入研究及大肠癌分子生物学的发展,诸多基于纳米材料搭载特定药物的新兴疗法用于大肠癌的治疗,包括光热疗法、磁热疗法、光动力疗法、声动力疗法以及化学动力疗法的应用,均取得较好效果.     

纳米材料在心肌梗死治疗中的进展

急性心肌梗死是冠心病的严重类型,为致死致残的主要原因。近年来,纳米材料作为一种新兴的治疗手段,在临床疾病的诊治中展现出巨大潜力。现从活性氧清除、炎症反应、心肌细胞凋亡、心肌纤维化、心脏血管再生、抗心肌梗死相关心律失常等方面阐述纳米材料在治疗心肌梗死中的进展,旨在为治疗心肌梗死提供新的思路。     

磁响应纳米材料在骨组织工程中的应用

［摘要］　生物材料作为骨组织替代物为治疗骨缺损或骨折不愈合提供了新的思路。传统纳米材料具有损伤细胞黏附、细胞毒性强等缺点。制备高效、毒性低的生物材料成为了目前组织工程领域的研究热点。磁性纳米粒子为骨再生提供磁力刺激,电磁场作为一种非侵入性物理疗法促进骨修复,两者结合制备的磁响应纳米材料在生物医学领域得到了广泛的研究和应用。该文对磁响应纳米材料的制备、分类及在骨组织工程中的应用作一综述。     

高通量测序技术在按蚊共生微生物研究中的应用

按蚊是疟疾的传播媒介,又称疟蚊。在按蚊体内,尤其是肠道内定殖着大量的共生微生物。共生微生物直接或间接地影响蚊虫的营养、发育、繁殖和免疫等重要生理活动。研究表明,肠道共生菌还能影响疟原虫的入侵、发育和传播。按蚊对常用杀虫剂逐渐产生抗性,疟原虫也对抗疟药产生了抗药性,严重阻碍了消除疟疾进程,迫切需要新的疟疾传播阻断战略。利用共生微生物控制和阻断疟疾传播是有潜力的方法之一,因此研究按蚊的共生微生物组成对理解按蚊、共生微生物以及病原体三者间的互作关系,识别用于防控疟疾的候选细菌有重要意义。高通量测序技术的应用有效克服了传统方法的局限性,极大地提高了对按蚊共生微生物多样性的认识。本文将从高通量测序技术在按蚊共生微生物组成、多样性和影响因素及其在疟疾防控中的应用进展进行综述。     

生物传感器及其在兽医临床检测中的应用

生物传感器技术是现代科技的前沿技术,是一种集现代生物技术与电子技术为一体的高科技产品,因其具有选择性好、灵敏度高、分析速度快、成本低、能在复杂环境中进行在线连续监测,特别是高度自动化、微型化与集成化等特点,从而获得蓬勃而迅速的发展,并在国民经济的各个领域如临床检测、生物医学、环境监测、食品、制药等方面得以广泛的应用。生物传感器的研究开发,     

生物芯片技术及其应用——生物芯片技术在病原微生物检测中的应用

生物芯片技术又称微阵列技术。根据芯片上的探针不同，可分为蛋白质芯片和基因芯片。目前生物芯片技术在病原微生物的诊断及抗药性基因、毒力基因、致病因子的检测等方面已取得了突破性进展，显示出诱人的应用前景。     

质谱技术在病原微生物诊断中的应用

质谱技术因其高灵敏度、特异性、自动化和高通量等特点,被广泛用于病原微生物蛋白质、多肽等的研究,为病原微生物诊断提供了新技术。本文以基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)和电喷雾(ESI)三重四极杆多反应监测(MRM)质谱技术在微生物诊断中的研究进展进行系统综述。     

碳纳米材料在心血管治疗方面的应用与挑战

心血管疾病是严重威胁全球人类生命健康的头号杀手.心脏病发作和卒中会导致心血管不可逆转的组织损伤,对此现有的治疗方案仅限于"损伤控制",而不是组织修复.纳米材料特别是碳纳米材料(包括石墨烯、碳纳米管、纳米金刚石、富勒烯和其他纳米碳同素异形体)的快速发展为心血管功能的恢复治疗提供了契机.现就近年来主要碳纳米材料在心血管疾病...     

高通量测序在肝硬化患者腹水、血清及粪便微生物群检测中的应用

肝硬化是慢性进展性肝病,且肝硬化患者极易发生感染,尤其腹水、血清、粪便的菌群变化与肝硬化的进展及并发症有关。但是,大多数患者因腹水、血液中的细菌丰度低无法进行有效的细菌培养,因此难以进行全面分析。二代测序技术的高通量和高速度优势可以用于病原体生物学及临床诊断,包括病原体检测和鉴定、菌株分型、微生物组学研究,从而帮助临床医师优化抗菌药物的使用。目前,二代测序技术不断成熟,临床上对微生物群的全基因组进行分析成为可能。     

核酸扩增技术在淋球菌检测中的研究进展

淋病是一种性传播疾病,其病原体是淋球菌。淋球菌主要寄生于人体尿道粘膜,导致人类泌尿生殖系感染。及时、准确地诊断淋球菌感染是控制淋病传播的关键,核酸扩增检测技术对淋球菌的临床确诊及治疗有重大意义。本文综述了核酸扩增技术在淋球菌检测中的应用进展。     

Colorimetric detection of DNA,small molecules,proteins, and ions using unmodified gold nanoparticles and conjugated polyelectrolytes

We have demonstrated a novel sensing strategy employing single-stranded probe DNA, unmodified gold nanoparticles, and a positively charged, water-soluble conjugated polyelectrolyte to detect a broad range of targets including nucleic acid (DNA) sequences, proteins, small molecules, and inorganic ions. This nearly “universal” biosensor approach is based on the observation that, while the conjugated polyelectrolyte specifically inhibits the ability of single-stranded DNA to prevent the aggregation of gold-nanoparticles, no such inhibition is observed with double-stranded or otherwise “folded” DNA structures. Colorimetric assays employing this mechanism for the detection of hybridization are sensitive and convenient—picomolar concentrations of target DNA are readily detected with the naked eye, and the sensor works even when challenged with complex sample matrices such as blood serum. Likewise, by employing the binding-induced folding or association of aptamers we have generalized the approach to the specific and convenient detection of proteins, small molecules, and inorganic ions. Finally, this new biosensor approach is quite straightforward and can be completed in minutes without significant equipment or training overhead.     

PCR技术在血吸虫感染检测中的应用

血吸虫病目前仍是一种严重危害人类健康的寄生虫病。多聚酶链反应(PCR)是分子生物学技术检测DNA最灵敏的方法之一,在近期血吸虫病检测与诊断研究中的应用越来越多。虽然各研究所用PCR技术的检测标本、靶基因选择各异,诊断效率也不尽相同,但是PCR作为一种高特异性敏感性检测方法,与其他检测方法相比仍颇具优势。本文综述了PCR技术在血吸虫感染检测中的应用情况。     

病原微生物实验室生物安全管理探讨

病原微生物实验室是医学高等院校开展病原微生物实验的场所,常常需要用到具有致病性的活菌或血液制品。加强实验人员、带教老师及学生实验室安全意识等显得尤为重要。作者对完善实验室管理制度、加强实验室教学的安全管理等工作进行了概述。     

Using photons to manipulate enzyme inhibition by an azobenzene-modified nucleic acid probe

The ability to inhibit an enzyme in a specific tissue with high spatial resolution combined with a readily available antidote should find many biomedical applications. We have accomplished this by taking advantage of the cis–trans photoisomerization of azobenzene molecules. Specifically, we positioned azobenzene moieties within the DNA sequence complementary to a 15-base-long thrombin aptamer and then linked the azobenzene-modified cDNA to the aptamer by a polyethylene glycol (PEG) linker to make a unimolecular conjugate. During the photoisomerization of azobenzene by visible light, the inhibition of thrombin is disabled because the probe hybridizes with the cDNA in the trans-azobenzene conformation so that the aptamer cannot bind its target thrombin. However, when UV light is applied, melting of the hairpin structure (duplex) is induced via trans-to-cis conversion, thereby changing conformation of the aptamer and making the aptamer free to bind to and inhibit its target thrombin. By using standard clotting assays, we measured the IC₂₀₀ of various probe designs in both states and concluded the feasibility of using photon energy to temporally and spatially regulate these enzymatic reactions. Thus, we can report the development of DNA probes in the form of photon-controllable (thrombin) inhibitors, termed PCIs, and we expect that this approach will be highly beneficial in future biomedical and pharmaceutical applications.     

Ability of Cricetomys rats to detect Mycobacterium tuberculosis and discriminate it from other microorganisms

Trained African giant pouched rats (Cricetomys gambianus) have potential for diagnosis of tuberculosis (TB). These rats target volatile compounds of Mycobacterium tuberculosis (Mtb) that cause TB. Mtb and nontuberculous mycobacteria (NTM) species are related to Nocardia and Rhodococcus spp., which are also acid-fast bacilli and can be misdiagnosed as Mtb in smear microscopy. Diagnostic performance of C.?gambianus on in?vitro-cultured mycobacterial and related pulmonary microbes is unknown. This study reports on the response of TB detection rats to cultures of reference Mtb, clinical Mtb, NTM, Nocardia; Rhodococcus; Streptomyces; Bacillus; and yeasts. Trained rats significantly discriminated Mtb from other microbes (p?相似文献   

改良压碎逸蚴法检测感染性钉螺

目的评价改良压碎逸蚴法检测感染性钉螺的检出率和工效。方法采用双盲对照实验,以压碎法作为金标准,比较改良压碎逸蚴法及压碎法的感染性钉螺检出率,并对尾蚴数进行定量。在现场应用中比较改良压碎逸蚴法、压碎法和逸蚴法的工效。结果改良压碎逸蚴法检出率为100％,每只感染性钉螺体内含尾蚴数（4778±1157）只,一定容积水样检获的尾蚴数与感染性钉螺数呈正相关。改良压碎逸蚴法的工效是压碎法的18．2倍,是逸蚴法的17．3倍。结论改良压碎逸蚴法能快速检测感染性钉螺,并能对感染性钉螺和尾蚴数定量,适用于大批量分处（段）检测阳性钉螺。     

FAD-dependent C-glycoside–metabolizing enzymes in microorganisms: Screening,characterization, and crystal structure analysis

C-glycosides have a unique structure, in which an anomeric carbon of a sugar is directly bonded to the carbon of an aglycone skeleton. One of the natural C-glycosides, carminic acid, is utilized by the food, cosmetic, and pharmaceutical industries, for a total of more than 200 tons/y worldwide. However, a metabolic pathway of carminic acid has never been identified. In this study, we isolated the previously unknown carminic acid-catabolizing microorganism and discovered a flavoenzyme “C-glycoside 3-oxidase” named CarA that catalyzes oxidation of the sugar moiety of carminic acid. A Basic Local Alignment Search Tool (BLAST) search demonstrated that CarA homologs were distributed in soil microorganisms but not intestinal ones. In addition to CarA, two CarA homologs were cloned and heterologously expressed, and their biochemical properties were determined. Furthermore, a crystal structure of one homolog was determined. Together with the biochemical analysis, the crystal structure and a mutagenesis analysis of CarA revealed the mechanisms underlying their substrate specificity and catalytic reaction. Our study suggests that CarA and its homologs play a crucial role in the metabolism of C-glycosides in nature.

Various low–molecular mass plant-derived compounds, such as flavonoids, are glycosylated. Glycosides can be classified as O-, C-, N-, and S- by the manner of linkage between a sugar and aglycone, which is the nonsugar moiety of glycosides (Fig. 1A). Hundreds of C-glycosides have been isolated from various living organisms and show various bioactivities (1–4).Open in a separate windowFig. 1.Schematic representation of O-glycosides and C-glycosides, the growth of Microbacterium sp. 5-2b, and HPLC analysis of reaction mixtures. (A) Structures of O-glycosides (Left) and C-glycoside (Right). The cleavage sites for deglycosylation are indicated by the dotted lines. (B, Left) Colonies of strain 5-2b on a culture plate containing carminic acid, the color of which is red. Strain 5-2b was cultured on this plate for 7 d. (B, Right) Corresponding to B, Left, the colonies of strain 5-2b are colored yellow, and the clear zone is indicated by a white dotted line so that it is easier to discern. (C) HPLC analysis of reaction mixtures; cell-free extracts of strain 5-2b were incubated with carminic acid for 0 min, 10 min, and 2 h. The numbers in this figure indicate carminic acid (1), compounds X₁ and X₂ (2, 3), and compound Y (kermesic acid, 4).Humans ingest these glycosides in botanical foods and metabolize them in the intestine. In the small intestine, lactase-phlorizin hydrolase, which is present on the luminal side of the brush border, hydrolyzes glycosides (5) and, in the large intestine, glycosides are metabolized by intestinal microorganisms (6). The resulting aglycones are taken up from the intestine and show many beneficial bioactivities, such as antimicrobial, antiviral, and antioxidative ones (7). The metabolism of glycosides is closely related to the expression of their biological activities.More than 100 glycoside hydrolase families in the CAZy database which hydrolyze glycosides to yield a sugar moiety and the corresponding aglycone have been identified from bacteria to mammals (8–11). However, C-glycosides are not deglycosylated by glycoside hydrolases, because the sugar moiety and the aglycone are linked by a carbon–carbon bond. In intestinal microorganisms, C-glycosides are deglycosylated through a two-step deglycosylation reaction consisting of oxidation of the sugar moiety and C–C bond cleavage (12–15). Although the enzymes catalyzing the two-step reaction have been identified (15), detailed biochemical characterization and crystal structure analysis have never been reported.To clarify the metabolism of C-glycosides in nature, we started our study by screening carminic acid–catabolizing microorganisms from soil. Carminic acid, which is extracted from cochineal insects, is a C-glycoside of an anthraquinone derivative and is very important in the food, cosmetic, and pharmaceutical industries as a natural “red dye” all over the world (16).In this study, we discovered a carminic acid–catabolizing microorganism and identified a C-glycoside–metabolizing enzyme, C-glycoside 3-oxidase (CarA), that catalyzes the first step of C-glycoside metabolism by oxidizing the C3 position of the sugar moiety. We also report the enzyme’s biochemical properties, crystal structure, and possible reaction mechanism.