Development and Evaluation of a Loop-mediated Isothermal Amplification(LAMP) Assay for Rapid Detection of Chinese Giant Salamander Ranavirus

Loop-mediated isothermal ampliifcation （LAMP） is a novel nucleic acid diagnostic method that can amplify rapidly a target template under isothermal conditions. In this study, a LAMP assay for rapid detection of Chinese giant salamander ranavirus（CGSRV） was developed from culture isolates and clinical samples. The LAMP assay was developed by designing one set of four speciifc primers, targeting the major capsid protein （MCP） gene of CGSRV. Reaction time and temperature were optimal for 40 min at 62°C. The developed LAMP assay is speciifc and highly sensitive for CGSRV detection, the detection limit could reach about 5 copies of cloned viral genomic fragments. The sensitivity of the LAMP assay was about 1000 and 10-fold higher than that of both conventional and nested PCR, respectively. The LAMP ampliifcation produces a typical ladder-like pattern of products on an agarose gel that can be visually inspected after addition of ethidium bromide. The LAMP assay was evaluated further with clinical samples, and the results indicated the suitability and simplicity of the test as a rapid diagnostic tool for the detection of CGSRV.

Pathological Changes in Andrias davidianus Infected with Chinese Giant Salamander Ranavirus

Chinese giant salamander ranavirus （CGSRV） is an emerging pathogen in captive populations of the Chinese giant salamander （Andrias davidianus）. We processed 140 morbid Chinese giant salamanders from seven captive breeding populations over five years, and describe the disease associated with CGSRV infection. The most common gross signs were significant swelling of the legs and coelomic cavity, erythema of the legs and ventrum in juveniles; cutaneous erosions and ulcerations in adults, particularly the limbs and the head; and marked petechial or ecchymotic hemorrhages of the internal organs, particularly the liver, spleen and kidney. Histological examination showed degeneration, necrosis, and inflammation in many organs, particularly in the organs where hemorrhage was observed. There was evidence of eosinophilic inclusion bodies in degenerated and necrotic cells. We identified virus particles and empty capsids without viral nucleoid in the inclusion bodies using electron microscopy. Virus particles were hexagonal or round shape, and appeared in paracrystalline arrays, aggregates, or singly. All enveloped viral particles were 140-160 nm. Polymerase chain reaction followed by sequencing verified that the virus particles were CGSRV. These results collectively support that CGSRV was the etiologic agent responsible for these mass die-offs of the Chinese giant salamander. The pathology described herein will be useful in diagnosing cases of ranaviral disease caused by CGSRV, and provide evidence that this pathogen is a significant threat to the Chinese giant salamander.

Cloning, Expression, and Immunogenicity Analysis of the CpsE Protein from Group B Streptococcus Isolated from Tilapia (Oreochromis Niloticus)

Group B Streptococcus (GBS) is a major cause of serious bacterial infection in numerous animal species. The production of capsular polysaccharide(CPs) is vital to GBS to evade host immunity. One of the genes that required for production of CPs, cpsE, has been determined to be well conserved in capsule gene cluster (cps).This study cloned the cpsE gene from Tilapia of GBS clinical isolate (serotype Ia) and expressed this gene with aid of pET-32a(+) in Escherichia coli BL21(DE3) competent cells to obtain high levels of the recombinant protein for further study about CpsE in fish and examination of its immunogenicity. The optimization of induction conditions (IPTG concentration, temperature and time) in E.coli was accomplished and let us to perform the recombinant protein induction at 37℃ for 3h,with 0.2mM IPTG in Luria Bertani (LB) medium. At the optimal conditions, recombinant protein was expressed in an insoluble form (inclusion bodies) and accounted for approximately 23% of the total protein. Purification by affinity chromatography yielded about 480mg fusion protein per liter culture.

A ratiometric optical thermometer with dual-color emission based on Eu^(2+)-doped CsCu_(2)I_(3) microcrystals

With the increasing demand for non-co ntact fluorescence intensity ratio-based optical thermometry,novel phosphor materials with high-efficiency,dual-emitting centers,and differentiable temperature sensitivity are highly desired,In this wo rk,rare earth Eu^(2+) ions were incorporated Wnto CsCu_(2)I_(3) microcrystals by solidstate reaction,Under a single UV excitation,the as-synthesized samples exhibit two emissions:452 nm blue emission from the 5d→4f transition of Eu^(2+)and 582 nm yellow emission from self-trapped exciton e mission of CsCu_(2)I_(3).The photoluminescence quantum yield reaches to 50%,The dual-band emission of Eu^(2+)-doped CsCu_(2)I_(3) shows different temperature responses in the range of 260-360 K.Based on fluorescence intensity ratio technology,the maximum absolute sensitivity and re Iative sensitivity are 0.091 K^(-1)(at 360 K) and 2.60%/K(at 260 K),respectively.These results suggest that Eu^(2+)-doped GsCu_(2)I_(3) could be a good candidate for highly sensitive optical thermometer.

碳纤维复合材料超声振动辅助RTM工艺的浸润特性

研究了织物类型、纤维体积分数和超声振动对树脂在碳纤维织物中流动特性的影响规律,设计了超声振动辅助RTM工艺过程中单向渗透率测量装置,开展了16组渗透率测试实验,并结合COMSOL软件仿真分析了织物中的树脂流动特性。研究表明,在相同纤维体积分数水平下,斜纹编织物的纤维束间隙通道比平纹织物的更宽,2/2斜纹编织织物渗透率比平纹织物提高了约21.5%。纤维体积分数与织物渗透率呈负相关,其函数关系与半经验公式Kozeny-Carman(KC)方程吻合较好。树脂流动过程中加入超声振动,其超声空化效应、加速度效应和微射流效应作用于纤维丝束表面,提高了织物渗透率约58.2%。有限元仿真模拟了椭圆形和近矩形纤维束截面设计的织物模型的流动过程,结果发现近矩形纤维束截面高流速区域范围更广,流体向纤维布夹层浸渍的速度分量更大。超声作用于织物纤维可能带动纤维丝束蠕动,使纤维束截面趋于近矩形状,从而提高了树脂对纤维织物的浸润性。上述研究结果对优化碳纤维复合材料成型工艺和成型性能具有一定的指导意义。

Contributions of Cs and Rb on Inhibiting Photo-induced Phase Segregation and En-hancement Optoelectronic Performances of MA_(1-y)XyPbI_(1.8)Br_(1.2)(X=Cs,Rb)Single Crystals

Introducing inorganic cation into hybrid organic-inorganic perovskites(HOIPs)has attracted great attention because of the enhancement stabilities without sacrificing their excellent optoelectronic properties.Here,we introduce Cs and Rb into MAPbI_(1.8)Br_(1.2)single crystals(SCs)to dig out the mixed cation effect on optoelectronic performances and phase stabilities.Both Rb and Cs can increase the lattice capacity,which is sufficient to relieve the lattice stress caused by photon energy,thus achieving the purpose of stabilizing the lattice structure and inhibiting migration of halide ions,compared with MAPbI_(1.8)Br_(1.2)SC.On the other hand,the smaller polarity of Rb and Cs reduces the electron-phonon coupling,thus significantly inhibiting the migration of halide ions.Meanwhile,through planar photo-detectors,MA_(0.9)Cs_(0.1)PbI_(1.8)Br_(1.2)-based device behaves much excellent optoelectronic performance(R=0.170 A/W,EQE=51.39%,D^(*)=4.42×10^(12)Jones,on/off ratio:~522).