重组酶介导的蓝氏贾第鞭毛虫特异性等温核酸扩增方法的建立及评价

目的　建立基于重组酶介导的等温扩增技术（RAA）的蓝氏贾第鞭毛虫核酸检测方法,并评价其检测敏感性和特异性。方法　选择蓝氏贾第鞭毛虫β?贾第素（β?giardin）基因作为检测靶基因,设计、合成特异性检测引物及荧光探针,建立荧光RAA检测体系。分别以不同拷贝数的重组质粒（含β?giardin基因靶序列）和不同浓度蓝氏贾第鞭毛虫基因组DNA为模板进行荧光RAA扩增,评价其检测敏感性;分别以蓝氏贾第鞭毛虫、日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板进行扩增,评价其检测特异性。结果　成功建立了蓝氏贾第鞭毛虫荧光RAA检测方法,其可在等温（39 ℃）条件下实现对靶基因片段的快速、特异性扩增（20 min内）。分别以重组质粒和蓝氏贾第鞭毛虫基因组DNA为模板,该方法的检测敏感性可达102拷贝/μL和1 pg/μL;以日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板的RAA检测结果均为阴性,具备较好特异性。结论　建立了一种操作简便、敏感、特异的可用于蓝氏贾第鞭毛虫核酸检测的荧光RAA方法。     

基于重组酶介导核酸等温扩增反应的曼氏血吸虫 基因检测方法的建立

目的　建立一种可用于曼氏血吸虫特异性基因片段检测的重组酶介导的核酸等温扩增方法（Recombinase?aided amplification, RAA）。方法　以曼氏血吸虫121 bp高重复基因片段作为靶序列,根据RAA反应原理设计、合成引物及荧光探针,建立并优化荧光RAA法反应体系。分别以不同拷贝数的含121 bp基因片段的重组质粒及不同浓度曼氏血吸虫基因组DNA为模板进行荧光RAA法扩增,评价该方法的敏感性;分别以日本和埃及血吸虫虫卵、十二指肠钩虫虫卵、华支睾吸虫囊蚴基因组DNA为模板进行荧光RAA法检测,评价其特异性。结果　建立的荧光RAA法可在39 ℃、20 min内特异性扩增曼氏血吸虫基因组DNA。以重组质粒为模板,荧光RAA法最低可检出的质粒拷贝数为10拷贝/μL;以基因组DNA为模板,荧光RAA法最低可检测浓度为0.1 fg/μL。以日本血吸虫虫卵、埃及血吸虫虫卵、十二指肠钩虫虫卵、华支睾吸虫囊蚴基因组DNA为模板进行荧光RAA法检测,结果均为阴性。结论　成功建立了一种可用于曼氏血吸虫DNA检测的荧光RAA法,该方法反应快捷、操作简便,敏感性和特异性均较好。     

The role of nitric oxide in ocular surface physiology and pathophysiology

Nitric oxide (NO) has a wide array of biological functions including the regulation of vascular tone, neurotransmission, immunomodulation, stimulation of proinflammatory cytokine expression and antimicrobial action. These functions may depend on the type of isoform that is responsible for the synthesis of NO. NO is found in various ocular tissues playing a pivotal role in physiological mechanisms, namely regulating vascular tone in the uvea, retinal blood circulation, aqueous humor dynamics, neurotransmission and phototransduction in retinal layers. Unregulated production of NO in ocular tissues may result in production of toxic superoxide free radicals that participate in ocular diseases such as endotoxin-induced uveitis, ischemic proliferative retinopathy and neurotoxicity of optic nerve head in glaucoma. However, the role of NO on the ocular surface in mediating physiology and pathophysiological processes is not fully understood. Moreover, methods used to measure levels of NO in the biological samples of the ocular surface are not well established due to its rapid oxidation. The purpose of this review is to highlight the role of NO in the physiology and pathophysiology of ocular surface and propose suitable techniques to measure NO levels in ocular surface tissues and tears. This will improve the understanding of NO's role in ocular surface biology and the development of new NO-based therapies to treat various ocular surface diseases. Further, this review summarizes the biochemistry underpinning NO's antimicrobial action.     

Fluorescence guided resection (FGR): A primer for oncology

Curative treatment for most cancer patients requires surgical removal of the tumor. Often though, residual disease is left behind negatively impacting tumor control and survival. Florescent Guided resection (FGR) is one type of Image Guided Surgery that offers the potential to improve outcomes for these patients. Currently, during FGR, a probe is preoperatively applied and allowed to concentrate in the tumor bed. At surgery appropriate light is applied to generate fluorescence which allows the surgeon to better visualize tumor extent. This improved visualization has translated both into enhanced rates for resection but also diminished rates of morbidity as less normal tissue need be removed to achieve negative margins. This paper will summarize the theory and practise of FGR as currently applied in clinical oncology including select outcomes and limitations of technique and technology.     

Recent advances in fluorescent labeling techniques for fluorescence microscopy

Tremendous progress in recent computer-controlled systems for fluorescence and laser-confocal microscopy has provided us with powerful tools to visualize and analyze molecular events in the cells. Various fluorescent staining and labeling techniques have also been developed to be used with these powerful instruments. Fluorescent proteins such as green fluorescent protein (GFP) allow us to directly label particular proteins of interest in living cells. This technique has been extended over a large area of cell biology, and a variety of fluorescent protein-derived techniques have been developed to visualize the functions and conditions of the molecules within living cells. In this review, we summarize the techniques for fluorescent staining and labeling for recent fluorescence microscopy.     

荧光蛋白标记的促红细胞生长素融合蛋白的设计和预测

目的：探讨pTRE顺式作用元件调控，EGFP标记hEPO(hEPO-EGFP)融合蛋白设计的合理性。方法：应用Gene Construction Kit2．5、www．expasy．com网站提供的分析方案，分析重组体的开放读框以及融合蛋白的柔性．并作蛋白质二级结构模拟。结果：重组体的转录受pTRE顺式作用元件调控，Linker所在部位柔性高，融合蛋白表达后，二级结构预测Linker不改变蛋白结构，完全符合作者设计EGFP标记hEPO融合蛋白的初衷。结论：重组蛋白设计合理，融合蛋白有很大可能保留了hEPO和EGFP的理化特性，为进一步的实践操作提供了可靠的理论基础。     

荧光腹腔镜下小鼠胃癌可视化成像的实验研究

目的探讨荧光腹腔镜下小鼠胃癌可视化成像在鉴别肿瘤和正常组织中的价值。方法共20只3~4周龄,体重20 g裸鼠。2只裸鼠右后肢皮下注射0.2 ml高表达HER-2基因的NCI-N87胃癌细胞悬液用于观察背部成瘤情况,1周后当瘤体直径达1 cm左右进行下一步实验观察。将0.2 ml高表达HER-2基因的NCI-N87胃癌细胞悬液注射于12只裸鼠胃黏膜下,建立裸鼠胃癌模型。将量子点与HER-2的单抗结合制作量子点纳米荧光探针。将12只胃癌模型裸鼠分为A、B组,每组6只,A组裸鼠尾静脉注射量子点纳米荧光探针100μl与裸鼠胃癌模型进行体内结合,B组裸鼠尾静脉先注射HER-2单克隆抗体再注射量子点纳米荧光探针100μl,C组6只正常生长的裸鼠尾静脉直接注射量子点纳米荧光探针100μl。最后利用改装后的荧光腹腔镜分别以15、30 min和1、2、4、8、12、24、30 h时间点观察不同时期裸鼠体内胃癌组织及其他部位的荧光显像,标本送检。结果裸鼠种瘤成功,胃癌组织在荧光腹腔镜下完成可视化成像,荧光探针结合后稳定性良好,荧光强度在1 h后达到峰值,30 h后荧光消失。发光组织病理切片证实为胃癌组织,免疫组化证实该组织高表达HER-2蛋白。结论量子点纳米荧光探针性质稳定,荧光强度1 h达到峰值,然后逐渐衰减,荧光腹腔镜下可清晰看到高表达HER-2的NCI-N87胃恶性肿瘤的边界和周围组织及淋巴结的转移情况。     

Toxicity of imine–iminium dyes and pigments: electron transfer,radicals, oxidative stress and other physiological effects

Although conjugation is well known as an important contributor to color, there is scant recognition concerning involvement of imine and iminium functions in the physiological effects of this class of dyes and pigments. The group includes the dyes methylene blue, rhodamine, malachite green, fuchsin, crystal violet, auramine and cyanins, in addition to the pigments consisting of pyocyanine, phthalocyanine and pheophytin. The physiological effects consist of both toxicity and beneficial aspects. The unifying theme of electron transfer–reactive oxygen species–oxidative stress is used as the rationale in both cases. Toxicity is frequently prevented or alleviated by antioxidants. The apparent dichotomy of methylene blue action as both oxidant and antioxidant is rationalized based on similar previous cases. This mechanistic approach may have practical benefit. This review is important in conveying, for the first time, a unifying mechanism for toxicity based on electron transfer–reactive oxygen species–oxidative stress arising from imine–iminium. Copyright © 2014 John Wiley & Sons, Ltd.     

Detection of Ochratoxin a Using Molecular Beacons and Real-Time PCR Thermal Cycler

We developed a simple and cheap assay for quantitatively detecting ochratoxin A (OTA) in wine. A DNA aptamer available in literature was used as recognition probe in its molecular beacon form, i.e., with a fluorescence-quenching pair at the stem ends. Our aptabeacon could adopt a conformation allowing OTA binding, causing a fluorescence rise due to the increased distance between fluorophore and quencher. We used real-time PCR equipment for capturing the signal. With this assay, under optimized conditions, the entire process can be completed within 1 h. In addition, the proposed system exhibited a good selectivity for OTA against other mycotoxins (ochratoxin B and aflatoxin M1) and limited interference from aflatoxin B1 and patulin. A wide linear detection range (0.2–2000 µM) was achieved, with LOD = 13 nM, r = 0.9952, and R² = 0.9904. The aptabeacon was also applied to detect OTA in red wine spiked with the same dilution series. A linear correlation with a LOD = 19 nM, r = 0.9843, and R² = 0.9708 was observed, with recoveries in the range 63%–105%. Intra- and inter-day assays confirmed its reproducibility. The proposed biosensor, although still being finalized, might significantly facilitate the quantitative detection of OTA in wine samples, thus improving their quality control from a food safety perspective.