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Bacillus sp. YA-14의 Xylanase 와 β- Xylosidase유전자의 재조합
나규흠,김지만,박희경,배동훈,유주현 한국산업미생물학회 1990 한국미생물·생명공학회지 Vol.18 No.2
토양으로부터 분리한 알카리내성 Bacillus sp. YA-14의 xylanase 유전자를 포함하고 있는 재조합 plasmid pYDC21의 EcoRI site에 β-xylosidase 유전자를 함유한 plasmid pYXL22의 5.7kb DNA 단편을 삽입시킴으로써 xylanase와 β-xylosidase 유전자가 동시에 연결된 약 13kb의 재조합 plasmid pYDK43을 제조하였다. Xylanase와 β-xylosidase를 동시에 생산하는 재조합 균주 E. coli HB101(pYDX43)이 기질인 xylan으로부터 직접 xylose까지 분해하는 것을 TLC상에서 확인하였다. E. coli HB101(pYDX43)이 생산하는 xylanase의 경우 공여균주인 Bacillus sp. YA-14보다 효소생산이 약 30% 증가하였으나 β-xylosidase의 경우 2.5배 감소하였다. A recombinant plasmid, pYDX43, was consturcted by inserting 5.7kb EcoRI DNA fragment of pYXL22 containing β-xylosidase gene into EcoRI site of pYDC21 which was carrying encoding xylanase gene. The end-product of xylan hydrolysis with crude cell extract of E. coli HB101 harboring pYDX43 was found to be xylose by TLC analysis. The productivity of xylanase with E. coli HB101(pYDX43) was 1.3 times higher than that with Bacillus sp. YA-14, but the synthesis of β-xylosidase was rather 2.5 times lower.
Bai Jing,Liu Xiao‐Na,Lu Ming‐Xing,Du Yu‐Zhou 한국곤충학회 2021 Entomological Research Vol.51 No.5
Temperature changes impact agricultural production and also influence the behavior and community structure of many insect species. Bemisia tabaci, is an invasive and destructive pest with at least 44 cryptic species and occurring in over 100 countries and regions. In this study, transcriptional profiling was used to evaluate the response of the Mediterranean (MED) cryptic species B. tabaci exposed to cold and hot temperature stress. In response to cold stress, 3,024 unigenes were differentially expressed and mapped to 39 Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathways. A total of 4,437 unigenes were differentially expressed during heat stress, and these represented 18 KEGG enrichment pathways. Quantitative RT-PCR was used to determine the relative expression level of the 11 HSP70 fragments; these were significantly up-regulated during high temperature stress relative to the control group that was maintained at 26°C. In conclusion, the transcriptome data indicated that B. tabaci responds to thermal stress via multiple genes and networks. Furthermore, HSP70 plays an important role in stress tolerance of the MED B. tabaci, especially during heat stress.
Mechanical properties of material in Q345GJ-C thick steel plates
Na Yang,Chao Su,Xiao-Feng Wang,Fan Bai 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.3
Thick steel plate is commonly found with mega steel structures but its properties have not been fully explored. Grade Q345GJ-C steel plate with thickness ranging from 60 mm to 120 mm are studied in this paper. Both the static and cyclic performance of material in different directions (horizontal and through-thickness directions) and locations (outer surface, 1/4 thickness and mid-depth) are experimentally obtained. The accumulative damage during cyclic loading is also calculated by using bilinear mixed hardening (BMH) constitutive relationship together with the Lemaitre's damage model. Results show that the static properties are better at the outer surface of thick steel plates than those at mid-depth. Properties in through-thickness direction are similar to those at mid-depth in the horizontal direction. The cyclic performance at different locations of a given plate is similar within the range of strain amplitude studied. However, when damage parameters identified from monotonic tensile tests are included in the numerical simulation of cyclic loading tests, damage is found accumulating faster at mid-depth than close to outer surface.
Partial Characterization of Proteases from Culture Filtrate of Mycobacterium tuberculosis
Na, Byoung-Kuk,Song, Chul-Yong,Park, Young-Kill,Bai, Gill-Han,Ki, Sang-Jae The Microbiological Society of Korea 1996 The journal of microbiology Vol.34 No.2
Two proteases were partially characterized from culture filtrate of Mycobacterium, tuberculosis KIT110. Their molecular weights were approximately 200 and 180 kDa, respectively and they exhibited similar enzymatic characteristics. These enzymes were inhibited significantly by EDTA and to some extent by EGTA. Their activity was enhanced by $Ca^{2+}$ and $Mg^{2+}$ to some degree. However, $Cu^{2+}$ and $Ag^{2+}$ completely inhibited the enzyme activity at the concentration of 2.5 and 5 mM, respectively. The optimal pH was 7.0 and optimal temperature was around $40^{\circ}C$. These enzymes were rapidly inactivated at $80^{\circ}C$. Therefore, they were heat-labile, neutral metalloproteases. These enzymes exhibited antigenicity shown by their reacting with sera from the partients with pulmonary tuberculosis. These enzymes were able to degrade serum proteins including hemoglobin, bovine serum albumin, lysozyme and immunoglobulin G and structural matrix protein such as type I collagen. Therefore, these enzymes may be thought to contribute to tissue necrosis and pathogenesis during infection.
A common evolutionary pathway for maintaining quorum sensing in Pseudomonas aeruginosa
Bai-min Lai,Hui-cong Yan,Mei-zhen Wang,Na Li,Dongsheng Shen 한국미생물학회 2018 The journal of microbiology Vol.56 No.2
In the bacterium Pseudomonas aeruginosa, the synthesis and secretion of extracellular protease is a typical cooperative behavior regulated by quorum sensing. However, this type of cooperative behavior is easily exploited by other individuals who do not synthesize public goods, which is known as the “tragedy of the commons”. Here P. aeruginosa was inoculated into casein media with different nitrogen salts added. In casein broth, protease (a type of public good) is necessary for bacterial growth. After 30 days of sequential transfer, some groups propagated stably and avoided “tragedy of the commons”. The evolved cooperators who continued to synthesize protease were isolated from these stable groups. By comparing the characteristics of quorum sensing in these cooperators, an identical evolutionary pattern was found. A variety of cooperative behaviors regulated by quorum sensing, such as the synthesis and secretion of protease and signals, were significantly reduced during the process of evolution. Such reductions improved the efficiency of cooperation, helping to prevent cheating. In addition, the production of pyocyanin, which is regulated by the RhlIR system, increased during the process of evolution, possibly due to its role in stabilizing the cooperation. This study contributes towards our understanding of the evolution of quorum sensing of P. aeruginosa.
Purification and Characterization of Extracellular Aspartic Proteinase of Candida albicans
Na, Byoung-Kuk,Lee, Seong-Il,Kim, Sin-Ok,Park, Young-Kil,Bai, Gill-Han,Kim, Sang-Jae,Song, Chul-Yong The Microbiological Society of Korea 1997 The journal of microbiology Vol.35 No.2
An extracellular proteinase of Candida albicans was purified by a combination of 0~75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephacryl S-200 HR molecular sieve chromatography. Its mlecular weight was approximately 41 kDa on SDS-PAGE and isoelectric point was 4.4. The enzyme was inhibited by pepstain A. Optimum enzyme activity ranged from pH 2.0 to 3.5 with its maximum at pH 2.5 and a temperature of 45$^{\circ}C$. The addition of divalent cations, $Ca^{2+}$, Zn$^{2+}$ and $Mg^{2+}$, resulted in no significant inhibition of enzymatic activity. However, some inhibitory effects were observed by Fe$^{2+}$, Ag$^{2+}$ and Cu$^{2+}$. With BSA as substrate, an apparent $K_m$ was determined to be 7$\times$10$^{-7}$ M and $K_i$, using pepstatin A as an inhibitor, was 8.05$\times$10$^{-8}$ M. N-terminal amino acid sequence was QAVPVTLXNEQ. Degradation of BSA and fibronectin was shown but not collagen, hemoglobin, immunoglobulin G, or lysozyme. The enzyme preferred peptides with Glu and Leu at the P$_1$ position, but the enzyme activity was highly reduced when the P$_2$ position was phe or pro. This enzyme showed antigenicity against sera of patients with candidiasis.
Chen, Bai Hui,Park, Joon Ha,Cho, Jeong Hwi,Kim, In Hye,Shin, Bich Na,Ahn, Ji Hyeon,Hwang, Seok Joon,Yan, Bing Chun,Tae, Hyun Jin,Lee, Jae Chul,Bae, Eun Joo,Lee, Yun Lyul,Kim, Jong Dai,Won, Moo-Ho,Kang Medknow PublicationsMedia Pvt Ltd 2015 Neural regeneration research Vol.10 No.2
<P><I>Oenanthe javanica</I> is an aquatic perennial herb that belongs to the <I>Oenanthe genus</I> in Apiaceae family, and it displays well-known medicinal properties such as protective effects against glutamate-induced neurotoxicity. However, few studies regarding effects of <I>Oenanthe javanica</I> on neurogenesis in the brain have been reported. In this study, we examined the effects of a normal diet and a diet containing ethanol extract of <I>Oenanthe javanica</I> on cell proliferation and neuroblast differentiation in the subgranular zone of the hippocampal dentate gyrus of adolescent rats using Ki-67 (an endogenous marker for cell proliferation) and doublecortin (a marker for neuroblast). Our results showed that <I>Oenanthe javanica</I> extract significantly increased the number of Ki-67-immunoreactive cells and doublecortin-immunoreactive neuroblasts in the subgranular zone of the dentate gyrus in the adolescent rats. In addition, the immunoreactivity of brain-derived neurotrophic factor was significantly increased in the dentate gyrus of the <I>Oenanthe javanica</I> extract-treated group compared with the control group. However, we did not find that vascular endothelial growth factor expression was increased in the <I>Oenanthe javanica</I> extract-treated group compared with the control group. These results indicate that <I>Oenanthe javanica</I> extract improves cell proliferation and neuroblast differentiation by increasing brain-derived neurotrophic factor immunoreactivity in the rat dentate gyrus.</P>