• 중국문학
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• 제96권
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• pp.145-175
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• 2018

본 연구는 청대 중기에 활동했던 장학성(章學誠)(1738-1801)의 사례를 통해 당시 '문인'의 존재방식과 글쓰기의 의미, 문화권력과 정치권력의 관계 등을 재고해 보려는 목적을 가지고 작성되었다. 여기에서 '문인'이란 '문학적인 글을 쓰는 작가(the literary man)'라는 협의의 개념보다 '문학적인 재능을 갖춘 지식인(the literary intelligentsia)', 영어의 'literati'에 해당하는 개념으로 사용되었다. 우선, 장학성은 건륭(乾隆)3년부터 가경(嘉慶)6년까지 64년의 인생을 살았던 인물로, 특히 18세기 중후반 중국 문인을 대표하는 인물 중 하나이다. 그는 절강성 회계(會稽) 출신으로 전형적인 강남의 사대부 가문에서 태어났다. 청소년기는 고향인 절강성 소흥과 호북성 응성(應城) 지역에서 교육받고 성장하였지만, 그에게 가장 큰 영향을 주었던 도시는 북경이었다. 건륭27년(1762), 25살의 나이에 북경(北京) 국자감(國子監)에 입학한 이후 그는 북경을 중심으로 활동하면서 직례(直隸), 하남, 안휘, 호북 등지를 떠도는 방랑생활을 하였다. 그는 18세기를 주도하였던 수많은 문인 학자들과 교유하였는데, 대표적인 후원자로는 심업부(沈業富), 구양근(歐陽瑾), 주분원(朱棻元), 주균(朱筠), 양국치(梁國治), 필원(畢沅), 사계곤(謝啓崑) 등을 거론할 수 있다. 그는 회시에 합격한 이후에도 출사(出仕)를 포기하고 재야 문인으로 사는 길을 선택하였는데, 후원자들을 통해 주로 가정교사, 서원의 산장(山長), 막료(幕僚) 등과 같은 비정규직 일자리를 통해 경제적인 문제를 해결하였다. 18세기 출사(出仕)를 포기했거나 관료로 있다가 사직한 문인들은 대부분 장학성과 같은 비정규 일자리를 통해 지식인으로서의 정체성을 유지하며 생계 문제를 해결하였다. 다음으로, 18세기 문인의 담론에서는 당시 학술계를 크게 의리(義理), 고거(考據), 문장(文章)(사장(詞章))으로 구분하였다. 이 셋의 의미와 가치, 위상을 어떻게 규정하고 평가할 것인가 하는 문제는 당시 논자에 따라 차이가 있었다. 하지만 전반적으로 문학적인 글인 '문장(文章)'은 학술적인 글인 '고거(考據)'와 '의리(義理)'에 비해 대체로 그 의미와 가치가 떨어지는 것으로 평가되고 인식되었다. 장학성의 글쓰기는 전체적으로 '문인의 글'보다는 '학자의 글'의 성격을 띠고 있으며, 그의 글쓰기의 가치도 문학적인 글보다는 학자적인 글에서 찾을 수 있다. "고증은 의리를 실증하고 문장은 그것을 표현하는 도구"라는 말로 요약되듯이, 그는 사학을 중심으로 의리와 고증을 통합하는 방식의 글쓰기를 통해 자기가 추구해야 될 학문적 정체성을 확립하였다. 마지막으로, 장학성을 비롯하여 전조망(全祖望), 원매(袁枚), 왕명성(王鳴盛), 조익(趙翼), 전대흔(錢大昕), 요내(姚鼐) 등은 출사를 포기하거나 관직에 들어섰다가 일찍 사직하고 훨씬 오랜 기간 동안 재야에서 강학(講學)과 글쓰기에 종사하는 삶을 살았다. 이들이 출사를 포기하거나 일찍 사직한 이유와 배경은 각기 다양하지만, 불후의 작품을 후세에 남기려는 원대한 포부와 욕망은 공통적인 부분일 수 있다. 이와 함께 청대 학술이 전문화되어 당시 문인들에게 관료와 학자의 길은 적절히 병행하기 어려운, 둘 중 하나를 선택해야 하는 문제였다는 점을 고려할 필요가 있다. 또한 청대 만주족이 주도적인 문화권력을 창출하지 못하면서 문화권력이 한족 문인의 개별적인 선택의 몫이 되어 가는 상황과도 관련이 있어 보인다.

• Journal of Microbiology
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• 제45권3호
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• pp.241-245
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• 2007

This study was conducted to determine the optimal conditions for introduction of exogenous DNA into Synechocystis sp. PCC 6803. Of the three transformation techniques studied, electroporation, ultrasonic transformation and natural transformation, natural transformation showed the highest efficiency. Additionally, this study demonstrated that the higher plasmid concentration and longer homologous recombining fragments resulted in a greater number of transformants. For successful transformation, the lowest concentration of plasmid was $0.02\;{\mu}g/ml$, and the shortest homologous recombining fragment was 0.2 kb. Use of Synechocystis sp. PCC 6803 in the logarithmic growth phase resulted in two-fold higher transformation rate than that of the same organism when cells in the latent phase or the plateau phase were used for transformation. Pretreatment of the host strain, Synechocystis sp. PCC 6803, with EDTA (2 mM) for two days prior to transformation increased the transformation efficiency by 23%. Additionally, incubation of the cells and DNA for 5 h under light conditions increased the transformation efficiency by two orders of magnitude. Moreover, recovery treatment of the cells before they were plated onto antibiotic medium also increased the transformation efficiency.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1109-1114
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• 2021

Chlamydia pneumoniae is a type of pathogenic gram-negative bacteria that causes various respiratory tract infections including asthma. Chlamydia species infect humans and cause respiratory infection by rupturing the lining of the respiratory which includes the throat, lungs and windpipe. Meanwhile, the function of interleukin-4 (IL-4) in Ch. pneumoniae respiratory infection and its association with the development of airway hyperresponsiveness (AHR) in adulthood and causing allergic airway disease (AAD) are not understood properly. We therefore investigated the role of IL-4 in respiratory infection and allergy caused by early life Chlamydia infection. In this study, Ch. pneumonia strain was propagated and cultured in HEp-2 cells according to standard protocol and infant C57BL/6 mice around 3-4 weeks old were infected to study the role of IL-4 in respiratory infection and allergy caused by early life Chlamydia infection. We observed that IL-4 is linked with Chlamydia respiratory infection and its absence lowers respiratory infection. IL-4R α2 is also responsible for controlling the IL-4 signaling pathway and averts the progression of infection and inflammation. Furthermore, the IL-4 signaling pathway also influences infection-induced AHR and aids in increasing AAD severity. STAT6 also promotes respiratory infection caused by Ch. pneumoniae and further enhanced its downstream process. Our study concluded that IL-4 is a potential target for preventing infection-induced AHR and severe asthma.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.771-780
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• 2014

A putative lipolytic enzyme gene, named as est9x, was obtained from a marine microbial metagenome of the South China Sea. Sequence analysis showed that Est9X shares lower than 27% sequence identities with the characterized lipolytic enzymes, but possesses a catalytic triad highly conserved in lipolytic enzymes of the ${\alpha}/{\beta}$ hydrolase superfamily. By phylogenetic tree construction, Est9X was grouped into a new lipase/esterase family. To understand Est9X protein in depth, it was recombinantly expressed, purified, and biochemically characterized. Within potential hydrolytic activities, only lipase/esterase activity was detected for Est9X, confirming its identity as a lipolytic enzyme. When using p-nitrophenol esters with varying lengths of fatty acid as substrates, Est9X exhibited the highest activity to the C2 substrate, indicating it is an esterase. The optimal activity of Est9X occurred at a temperature of $65^{\cric}C$, and Est9X was pretty stable below the optimum temperature. Distinguished from other salt-tolerant esterases, Est9X's activity was tolerant to and even promoted by as high as 4 M NaCl. Our results imply that Est9X is a unique esterase and could be a potential candidate for industrial application under extreme conditions.

• Journal of Microbiology and Biotechnology
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• 제20권9호
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• pp.1351-1358
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• 2010

The demand for ${\beta}$-glucosidases insensitive to product inhibition is increasing in modern biotechnology, for these enzymes would improve the process of saccharification of lignocellulosic materials. In this study, a ${\beta}$-glucosidase gene that encodes a 442-amino-acid protein was isolated from a marine microbial metagenomic library by functional screening and named as bgl1A. The protein was identified to be a member of the glycoside hydrolases 1 family, and was recombinantly expressed, purified, and biochemically characterized. The recombinant ${\beta}$-glucosidase, Bgl1A, exhibited a high level of stability in the presence of various cations and high concentrations of NaCl. Interestingly, it was activated by glucose at concentrations lower than 400 mM. With glucose further increasing, the enzyme activity of Bgl1A was gradually inhibited, but remained 50% of the original value in even as high as 1,000 mM glucose. These findings indicate that Bgl1A might be a potent candidate for industrial applications.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1933-1942
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• 2016

A novel ${\alpha}-glucoside$ hydrolase (named PspAG97A) from glycoside hydrolase family 97 (GH97) was cloned from the deep-sea bacterium Pseudoalteromonas sp. K8, which was screened from the sediment of Kongsfjorden. Sequence analysis showed that PspAG97A belonged to GH97, and shared 41% sequence identity with the characterized ${\alpha}-glucoside$ BtGH97a. PspAG97A possessed three key catalytically related glutamate residues. Mutation of the glutamate residues indicated that PspAG97A belonged to the inverting subfamily of GH97. PspAG97A showed significant reversibility against changes in salt concentration. It exhibited halophilic ability and improved thermostability in NaCl solution, with maximal activity at 1.0 M NaCl/KCl, and retained more than 80% activity at NaCl concentrations ranging from 0.8 to 2.0 M for over 50 h. Furthermore, PspAG97A hydrolyzed not only ${\alpha}-1,4-glucosidic$ linkage, but also ${\alpha}-1,6-$ and ${\alpha}-1,2-glucosidic$ linkages. Interestingly, PspAG97A possessed high catalytic efficiency for long-chain substrates with ${\alpha}-1,6-linkage$. These characteristics are clearly different from other known ${\alpha}-glucoside$ hydrolases in GH97, implying that PspAG97A is a unique ${\alpha}-glucoside$ hydrolase of GH97.

• ALGAE
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• 제35권3호
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• pp.253-262
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• 2020

Haematococcus pluvialis is a commercial microalga that can produce high quantities of astaxanthin. Under induced conditions, some important changes in the subcellular structures related to astaxanthin accumulation were observable. For example, a large number of astaxanthin granules, oil structures and starch granules appeared in the thick-walled cells; Astaxanthin granules gradually dissolved into the oil structures and spread throughout the entire cell with the fusion and diffusion process of oil structures during the middle and late stages of induction; The plastoglobules were closed to the newly formed structures, and some plastoglobules would abnormally increase in size under stress. Based on observations of cell damage, the degradation of membrane structures, such as chloroplasts, was found to be the primary form of damage during the early stage of induction. During the middle stage of induction, some transparent holes were exposed in the dissolving astaxanthin granules in the cytoplasm. In thick-walled cells, these transparent holes were covered by oil substances dissolving astaxanthin, thereby avoiding further damage to cells. Given the relatively few oil structures, in non-thick-walled cells, the transparent holes expanded to form multiple transparent areas, eventually resulting in the rupture and death of cells. These results suggested that the high level of synthesis and the wide range diffusion of oil explained the expansion of astaxanthin in H. pluvialis.