Development of Electrochemical Biosensor for Detection of PML/RARα Fusion Gene in Acute Promyelocytic Leukemia

针对急性早幼粒细胞白血病(APl)中PMl/rArα融合基因的碱基序列,设计了锁核酸(lnA)修饰的发夹结构捕获探针,结合信号探针构建新型的“三明治“电化学传感模式。信号探针末端修饰的生物素可与酶上的亲和素结合,通过检测酶催化H2O2氧化底物3,3',5,5'-四甲基联苯胺(TMb)产生的电化学信号,实现对靶序列的检测。该传感器可识别和定量检测PbS缓冲液中人工合成的PMl/rArα融合基因序列。结果表明,该传感器能很好地区分互补序列、单碱基及多碱基错配序列,杂交电流值与目标链浓度在1.0x10-11~1.6x10-10 MOl/l范围内呈较好的线性关系,检出限为1.0x10-13 MOl/l。同时,该新型传感器成功地用于无稀释人血清中PMl/rArα融合基因的检测,具有特异性强、灵敏度高和重复性好的优点,有望用于临床实际样品的检测,进而实现临床上急性早幼粒细胞白血病的早期诊断及预后判断。A novel DNA electrochemical probe(locked nucleic acid,LNA) was designed and involved in constructing an electrochemical DNA biosensor for the detection of PML/RARα fusion gene in acute promyelocytic leukemia(APL).This biosensor was based on a "sandwich" detection strategy,which involved a pair of LNA probes,e.g.hairpin capture probe and reporter probe.Streptavidin-HRP was bound to biotin labeled at the end of reporter probe via streptavidin-biotin affinity binding.In the presence of hydrogen peroxide(H2O2),HRP catalyzed the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidene(TMB) to offer an enzymatically amplified electrochemical current signal for the detection of target DNA.This sensor was applied in the direct quantitative detection of synthetic PML/RARα fusion gene in PBS buffer.The results indicated that the biosensor showed an excellent specificity to distinguish the complementary sequence and different mismatch sequences.A linear relationship between the amperometric signal and the target concentration was obtained in the range of 1.0×10-11-1.6×10-10 mol/L with a detection limit of 1.0×10-13 mol/L.In addition,the biosensor was used for the determination of PML/RARα fusion gene in human serum samples without dilution with high sensitivity,selectivity and good repeatability.This method would be expected to use in real sample for further solving the actural problems of early diagnosis and prognosis monitoring of APL.863计划资助项目(2008AA02Z433);福建省高校产学研科技重点项目(2010Y4003);国家自然科学基金资助项目(20805006;20975021);福建省自然科学基金资助项目(2010J05019

骨髓干细胞移植后 mdx 鼠腓肠肌病理及 Dystrophin 的表达变化

【目的】研究骨髓干细胞移植后 mdx 鼠腓肠肌组织病理变化及 dystrophin 的动态表达变化。【方法】7～9 周 mdx 鼠 20 只平均分为 4 组, 放疗后移植 1.2×107 个 /只同种异基因全骨髓干细胞, 于移植后 4 周、8周、12 周及 16 周应用 HE 染色观察细胞形态 及 核中心移位 ( CNF) , 免 疫组化及 Western blot 方法检测dystrophin 表达变化, C57 鼠和未治疗 mdx 鼠各 5 只作阳性和阴性对照。【结果】C57 鼠腓肠肌横切面可见肌细胞大小形态基本一致, 无核中移现象。各细胞移植治疗组和对照组 mdx 鼠均有大量的炎细胞浸润, 核中心移位明显。未治疗 mdx 鼠 CNF 最高, 可达 70%左右, 移植后 4 周、12 周和 16 周, CNF 比例分别为 55%、50%和 44%。免疫荧光结果 C57 鼠肌膜呈完整的网状绿色荧光, mdx 鼠肌膜基本未见绿色荧光; 移植后 4 周肌膜 dystrophin阳性纤维数大约占细胞总数的 1%, 随时间延长表达渐渐增多, 8 周、12 周和 16 周时阳性细胞数分别占细胞总数的 5%、10%和 15%。Western blot 结果 mdx 鼠无 dystrophin 的表达, 野生型 C57 鼠表达量最多 , 移植后 4 周mdx 鼠仅见微弱表达, 随时间延长表达量渐增, 移植后 16 周表达量较移植 8 周明显增加。【结论】骨髓干细胞移植后 mdx 鼠腓肠肌 CNF 随移植时间延长逐渐减少, dystrophin 的表达随时间延长增多, 提示骨髓干细胞移 植后长久持续参与受损骨骼肌的修复与再生

白鹤停歇与越冬生态学研究现状及展望

白鹤(Grus leucogeranus)为国家Ⅰ级重点保护动物及IUCN极危(CR)物种,野外种群数量4 000只左右。江西鄱阳湖是全球白鹤最主要的越冬地,几乎全球整个白鹤种群(超过99%)在该区域越冬。学者研究显示:气候、水位、生境类型、人为干扰等因素会对白鹤停歇地及越冬地的种群数量、活动节律、食性等产生影响。白鹤春秋迁徙期会以不同的策略,沿着相似的路线迁徙,具有一定的专一性。白鹤以植物性食物为主,对栖息地有选择偏好。近年来,人工生境成为白鹤重要的觅食越冬地。本文在总结前人的研究基础上,提出了一些白鹤保护措施及研究展望

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies