Identification of highly pathogenic Beauveria bassiana strain against Pieris rapae larvae

Jun‐Nan Ding,Yong-cai LAI 한국곤충학회 2018 Entomological Research Vol.48 No.5

Seven different strains of Beauveria bassiana were used in a bioassay on Pieris rapae larvae. The results showed that an B. bassiana strain showed relatively high pathogenicity towards P. rapae larvae. The adjusted mortality rate was 92.86 %, and the infection rate was 85.71 % in 10 days post inoculation. Molecular identification was performed to identify the unknown strain. Internal Transcribed Spacer sequence analysis showed that the polymerase chain reaction amplicon length of the unknown strain of Beauveria sp. was 573 bp, and sequence similarity to the known B. bassiana sequences in the NCBI database was 99 %. The B. bassiana strain was named Bb01. The changes of proteins and PPO of P. rapae larvae infected by B. bassiana Bb01 strain at different times was determined. The activity of PPO increased in 1–6 d and decreased in 7 d again after inoculation. The B. bassiana invaded into the insect body affected the balance of the proteins and PPO.

Ultrastructural observations of Beauveria bassiana infection in Xylotrechus rusticus larvae

Jun‐Nan Ding,De-Fu CHI 한국곤충학회 2018 Entomological Research Vol.48 No.3

In the present study we investigated the infection process of Beauveria bassiana on Xylotrechus rusticus larvae using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM results showed that B. bassiana spores germinated on the surface of the larval body and invaded the larva as an appressorium. The hyphae then germinated from the spores and spread throughout the larval body. After the death of the larva, conidiophores formed at one end of the hypha on the surface of the larval body and prepared for a new round of infection. The TEM results showed severe damage to the larval cuticle after hyphae infection. The structure of the cuticle became thinner and eventually flocculent; muscle tissues were dissociated and eventually stuck to the hyphae, and the corpus adiposum was loose and deformed, and eventually degraded.

Biochemical Characterization of a GDSL-Motif Esterase from Bacillus sp. K91 with a New Putative Catalytic Mechanism

( Jun Mei Ding ),( Ting Ting Yu ),( Lian Ming Liang ),( Zhen Rong Xie ),( Yun Juan Yang ),( Jun Pei Zhou ),( Bo Xu ),( Jun Jun Li ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.11

The esterase gene Est8 from the thermophilic bacterium Bacillus sp. K91 was cloned and expressed in Escherichia coli. The monomeric enzyme exhibited a theoretical molecular mass of 24.5 kDa and an optimal activity around 50°C at pH 9.0. A model of Est8 was constructed using a hypothetical YxiM precursor structure (2O14_A) from Bacillus subtilis as template. The structure showed an α/β-hydrolase fold and indicated the presence of a typical catalytic triad consisting of Ser-11, Asp-182, and His-185, which were investigated by site directed replacements coupled with kinetic characterization. Asp-182 and His-185 residues were more critical than the Ser-11 residue in the catalytic activity of Est8. A comparison of the amino acid sequence showed that Est8 could be grouped into the GDSL family and further classified as an SGNH hydrolase. Est8 is a new member of the SGNH hydrolase subfamily and may employ a different catalytic mechanism.

Production and Characterization of Ethanol- and Protease-Tolerant and Xylooligosaccharides-Producing Endoxylanase from Humicola sp Ly01

( Jun Pei Zhou ),( Qian Wu ),( Rui Zhang ),( Yu Ying Yang ),( Xiang Hua Tang ),( Jun Jun Li ),( Jun Mei Ding ),( Yan Yan Dong ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.6

This paper reports the production and characterization of crude xylanase from the newly isolated Humicola sp. Ly01. The highest (41.8 U/ml) production of the crude xylanase was obtained under the optimized conditions (w/v): 0.5% wheat bran, 0.2% KH2PO4, and 0.5% peptone; initial pH 7.0; incubation time 72 h; 30℃; and 150 rpm. A considerable amount of the crude xylanase was induced using hulless barley bran or soybean meal as the carbon source, but a small amount of the enzyme was produced when supplementary urea was used as the nitrogen source to wheat bran. The crude xylanase showed apparent optimal cellulase-free xylanase activity at 60℃ and pH 6.0, more than 71.8% of the maximum xylanase activity in 3.0-30.0% (v/v) ethanol and more than 82.3% of the initial xylanase activity after incubation in 3.0-30.0% (v/v) ethanol at 30℃ for 2 h. The crude xylanase was moderately resistant to both acid and neutral protease digestion, and released 7.9 and 10.9 μmol/ml reducing sugar from xylan in the simulated gastric and intestinal fluids, respectively. The xylooligosaccharides were the main products of the hydrolysis of xylan by the crude xylanase. These properties suggested the potential of the crude enzyme for being applied in the animal feed industry, xylooligosaccharides production, and high-alcohol conditions such as ethanol production and brewing.

Transcriptome analysis of male and female mature gonads of Japanese scallop Patinopecten yessonsis

Jun Ding,Dan Yang,Chao Yin,Yaqing Chang,Yan Dou,Zhenlin Hao 한국유전학회 2016 Genes & Genomics Vol.38 No.11

The Japanese scallop Patinopecten yessoensis is an important commercial culture shellfish in China and Japan. In addition to its commercial interest, it has also attracted much attention because of its value in studying sex determination and differentiation mechanisms. Herein, two transcriptome libraries from male and female gonads at maturing stage were constructed. The two libraries were paired-end sequenced using Illumina sequencing techniques. A total of 81,986,898 cleaned reads were obtained, and assembled into 29,897 unigenes by using Trinity software and removing redundancy. Compared with the public Swiss-Prot and NR databases by BlastX, 9354 unigenes were significantly matched to known unique proteins. As determined by GO annotation and KEGG pathway mapping, functional annotation of the unigenes uncovered diverse biological functions and processes. After comparing the two transcriptome libraries, 8652 upregulated and 2973 down-regulated genes were identified in the male gonads. According to annotation information, at least 30 genes related to sex determination and differentiation, such as Dmrt1, Sox9, fem1 and vasa, were identified and characterized. The expression patterns of the random eight genes were then validated by quantitative real-time PCR (qRT-PCR) suggesting the high reliability of RNA-Seq results. The study provides an archive for further studies of molecular mechanisms of bivalve sex determination and differentiation.

Overexpression of CXCL2 inhibits cell proliferation and promotes apoptosis in hepatocellular carcinoma

( Jun Ding ),( Kangdi Xu ),( Jie Zhang ),( Bingyi Lin ),( Yubo Wang ),( Shengyong Yin ),( Haiyang Xie ),( Lin Zhou ),( Shusen Zheng ) 생화학분자생물학회(구 한국생화학분자생물학회) 2018 BMB Reports Vol.51 No.12

C-X-C motif chemokine ligand 2 (CXCL2) is a small secreted protein that exhibits a structure similar to the proangiogenic subgroup of the CXC chemokine family. Recently, accumulating evidence suggests that chemokines play a pivotal role in cancer progression and carcinogenesis. We examined the expression levels of 7 types of ELR+ CXCLs messenger RNA (mRNA) in 264 clinical samples. We found that CXCL2 expression was stably down-regulated in 94% of hepatocellular carcinoma (HCC) specimens compared with paired adjacent normal liver tissues and some HCC cell lines. Moreover, CXCL2 overexpression profoundly attenuated HCC cell proliferation and growth and induced apoptosis in vitro. In animal studies, we found that overexpressing CXCL2 by lentivirus also apparently inhibited the size and weight of subcutaneous tumours in nude mice. Furthermore, we demonstrated that CXCL2 induced HCC cell apoptosis via both nuclear and mitochondrial apoptosis pathways. Our results indicate that CXCL2 negatively regulates the cell cycle in HCC cells via the ERK1/2 signalling pathway. These results provide new insights into HCC and may ultimately lead to the discovery of innovative therapeutic approaches of HCC. [BMB Reports 2018; 51(12): 630-635]

Numerical Simulation for TGO Crack Propagation near a surface groove in an Alumina Forming Alloy upon Thermo-Mechanical loading Cycles

Ding Jun,F.X. Li,Ki-Ju Kang 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

In this work, the nucleation and propagation of crack in thermally grown oxide (TGO) due to displacement instability of the surface groove in Fecralloy substrate, subjected to multiple thermo-mechanical loading cycles, has been studied using the finite element method. Assumptions and referring about the material properties are minimized for rigorous reality. Most of the material properties including TGO growth and yield strength for TGO and substrate are based on the results experimentally obtained in-house. The material property change method is employed to model TGO formation cycle by cycle, and the creep properties for constituent materials are also incorporated. Based on the finite element procedure developed by ourselves, double nodes at the same locations are placed along the interface of the potential crack initiation, and these nodes are tied together as one node at the location. The first simulation aims at identifying the node at which the stress exceeds the critical stress of TGO material, and then releasing the nodes to the target node ahead for modeling the crack propagation. The progress repeats many times until a through crack was initiated in TGO films. The result shows that the simulation can agree acceptably with the experiment and reproduce the initiation and propagation of crack in TGO increasingly.

Numerical Analysis for the Evolution of Surface Morphology of an Alumina Forming Alloy during Thermal-Mechanical Cycling

Ding Jun,F.X. Li,Anette M. Karlsson,Ki-Ju Kang 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Morphology change in surface grooves embedded in the TGO forming material substrate is a fundamental source of failure in some thermal barrier systems. In this work, the morphology instabilities on Fecralloy substrate due to the thermal-mechanical loading cycles has been explored with the variation of mechanical load. Assumptions and referring about the material properties are minimized for rigorous reality. Most of the material properties including TGO growth are based on the results experimentally obtained in-house. Employed on the finite element procedures developed by ourselves, the effects of creep of TGO and substrate on the morphology of surface grooves have been investigated. Comparison made between presence of creep and absence of creep consideration in finite element analysis shows that the creep deformation plays a central role in the displacement instabilities of TGO under thermal-mechanical loading cycles especially for the case of the relatively small magnitude of mechanical loading.

Alone in the Game : Dynamic Spread of Churn Behavior in a Large Social Network a Longitudinal Study in MMORPG

Jun Ding,Daqi Gao,Xiaohong Chen 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.3

Churn is a defection from a service provider. This study explores the role of social network in customers’ churn behavior .As the saying goes; customer is the god in service-based industries. Since the cost of customer acquisition is much greater than the cost of customer retention, customer churn prediction is more and more important. So far, research on churn prediction has involved user profile factors and social factors, but the analysis lacks interpretability and predictive horizon. In this paper, for a better understanding of churn behavior in MMORPG, we use longitudinal statistical models to examine whether the churn behavior in one person is associated with the churn of his friends on a complete data set of an entire society. Discernible clusters of active persons and inactive persons are visible in the network, and the relationship between people’s churn behavior extends up to three separations. Besides, we provide quantitative evidence for the strong ties hypothesis. The higher the number of common friends two persons have, the influence between them is more significant. At last, we use mixed effects cox models to predict churn in the future. Our study can provide a long forecast horizon, it is an obvious advantage to prevent the churn of a person.

Response of Saccharomyces cerevisiae to Ethanol Stress Involves Actions of Protein Asrlp

( Jun Mei Ding ),( Xiao Wei Huang ),( Na Zhao ),( Feng Gao ),( Qian Lu ),( Ke Qin Zhang ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.12

During the fermentation process of Saccharomyces cerevisiae, yeast cells must rapidly respond to a wide variety of external stresses in order to survive the constantly changing environment, including ethanol stress. The accumulation of ethanol can severely inhibit cell growth activity and productivity. Thus, the response to changing ethanol concentrations is one of the most important stress reactions in S. cerevisiae and worthy of thorough investigation. Therefore, this study examined the relationship between ethanol tolerance in S. cerevisiae and a unique protein called alcohol sensitive RING/PHD finger 1 protein (Asr1p). A real-time PCR showed that upon exposure to 8% ethanol, the expression of Asr1 was continuously enhanced, reaching a peak 2 h after stimulation. This result was confirmed by monitoring the fluorescence levels using a strain with a green fluorescent protein tagged to the C-terminal of Asr1p. The fluorescent microscopy also revealed a change in the subcellular localization before and after stimulation. Furthermore, the disruption of the Asr1 gene resulted in hypersensitivity on the medium containing ethanol, when compared with the wild-type strain. Thus, when taken together, the present results suggest that Asr1 is involved in the response to ethanol stress in the yeast S. cerevisiae.