• 생명과학회지
• /
• 제25권6호
• /
• pp.631-637
• /
• 2015

Streptmyces avidinii에서 발현되는 Streptavidin은 vitamin H인 d-biotin 4분자에 결합하며 해리상수(Kd)가 10⁻¹⁵ M를 나타내는 아주 강한 비공유결합이다. 이러한 streptavidin과 biotin 상호간의 강한 결합력은 수많은 생물체 분자들의 탐지 및 특징을 연구하는데 응용되어져 왔으므로 Escherichia coli에서 수용성 streptavidin의 기능적 발현에 대한 연구는 매우 유용하다. 즉 Escherichia coli에서 streptavidin을 발현시키기 위해 streptavidin유전자를 T7 RNA polymerase/T7 promoter를 이용하는 pET-22b 플라스미드로 클로닝하였다. 또한 N-말단에 pelB leader를 포함하여 발현된 streptavidin의 periplasmic space로 운반하여 수용성 단백질형태의 분비를 촉진하였으며 C-말단에는 6개의 polyhistidine tags를 두어 정제하는데 사용되었다. 정제된 streptavidin단백질은 10-20 mg/ml 의 높은 회수율을 나타내었으며 SDS-PAGE에서 가열하는 경우 변성되어 17 kD인 monomer형태를, 가열하지 않는 경우에는 68 kDa으로 원래의 tetramer형태를 나타내었다. 따라서 streptavidin의 tetramer 구조는 비공유결합에 의해 이루어짐을 알 수 있었다. Size-exclusion chromatography에 의한 streptavidin의 구조 역시 tetramer를 재확인할 수 있었다. 정제된 수용성 streptavidin은 Westernblot실험에서 biotinylation된 단백질을 탐지하였으며 이 결과는 정제된 streptavidin이 biotin에 결합하는 기능이 존재함을 나타내었다. 이상의 모든 결과를 종합해보면 본 연구에서 구축된 발현시스템을 통하여 발현된 streptavidin은 높은 회수율을 나타내어 대량생산이 가능하였으며 자연상태의 streptavidin과 동일한 homotetramer를 형성하고 biotin에 결합할 수 있는 기능을 나타내었다.

• Journal of Microbiology and Biotechnology
• /
• 제23권4호
• /
• pp.545-554
• /
• 2013

Plasmid isolation of kimchi-derived Weissella cibaria KLC140 revealed six different plasmids. The smallest plasmid, pKW2124, was DNA sequenced and characterized, showing 2,126 bp with a GC content of 36.39% and five putative open reading frames (ORFs). In silico analysis of these ORFs showed ORF1 encodes a putative replication protein similar to rolling circular replication proteins from other lactic acid bacteria. However, a single-stranded intermediate was not detected when S1 nuclease was treated, suggesting it may follow theta replication. Interestingly, the replication initiation site of this plasmid is 100% identical to other plasmids from lactic acid bacteria, suggesting it may function for replication initiation. To construct a surface layer expression vector, pTSLGFP, slpA encoding the surface layer protein from Lactobacillus acidophilus was PCR amplified and fused with the gfp gene, forming a SLGFP fused gene. The plasmid pKW2124 was cloned into the XbaI site of pUC19, forming an Weissella-E. coli shuttle vector pKUW22. NheI-linearized pTSLGFP was ligated into pKUWCAT containing pKUW22 and the chloramphenicol acetyltransferase gene from pEK104, resulting in an 8.6 kb pKWCSLGFP surface layer expression vector. After transformation of this vector into W. cibaria KLC140, a GFP fluorescence signal was detected on the surface of the transformant, substantiating production of SLGFP fused protein and its secretion. This is the first report for construction of a Weissella surface layer expression vector, which may be useful for surface layer production of beneficial proteins in Weissella.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권4호
• /
• pp.498-503
• /
• 2003

Luteinizing hormone as other glycoprotein hormones is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a specific $\beta$-subunit. The correct conformation of the heterodimer is important for efficient secretion, hormonal-specific post-translational modifications, receptor binding and signal transduction. To determine whether $\alpha$- and $\beta$- subunits can be synthesized as a single polypeptide chain (tethered-bLH and -bFSH) and also display biological activities, the tetheredbLH and -bFSH molecules were constructed and transfected into chinese hamster ovary (CHO-K1) cells. LH and FSH activities were assayed by using the human embryonic kidney (HEK) 293 cells expressing rat LH and FSH receptor genes. The tethered-bLH and - bFSH proteins were efficiently secreted and showed a similar activity to the dimeric bovine LH and FSH $\alpha$/$\beta$ wild type and native purified from bovine pituitary. The tethered-molecules can be permit development of potent new analogues that stimulate ovarian development. Taken together, a single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds. These data indicate the potentiality of the single chain approach to further investigate structurefunction relationships of LH and FSH.

• Journal of Ginseng Research
• /
• 제44권3호
• /
• pp.453-460
• /
• 2020

Background: BIOGF1K, a fraction of Panax ginseng, has desirable antimelanogenic, anti-inflammatory, and antiphotoaging properties that could be useful for treating skin conditions. Because its potential positive effects on allergic reactions in skin have not yet been described in detail, this study's main objective was to determine its efficacy in the treatment of atopic dermatitis (AD). Methods: High-performance liquid chromatography was used to verify the compounds in BIOGF1K, and we used the (3-4-5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide method to determine its cytotoxicity in RBL-2H3 and HMC-1 cell lines. RBL-2H3 cells were induced using both anti-DNP-IgE/DNP-BSA and calcium ionophore (A2187) treatments, whereas HMC-1 cells were induced using A2187 alone. To measure mast cell degranulation, we performed histamine (enzyme-linked immunosorbent assay) and β-hexosaminidase assays. To quantify interleukin (IL)-4, IL-5, and IL-13 levels in RBL-2H3 cells, we performed quantitative polymerase chain reaction (PCR); to quantify expression levels of IL-4 and IL-13 in HMC-1 cells, we used semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Finally, we detected the total and phosphorylated forms of extracellular signal-regulated kinase, p-38, and c-Jun N-terminal kinase proteins by immunoblotting. Results: BIOGF1K decreased the AD response by reducing both histamine and β-hexosaminidase release as well as reducing the secretion levels of IL-4, IL-5, and IL-13 in RBL-2H3 cells and IL-4 and IL-13 in HMC-1 cells. In addition, BIOGF1K decreased MAPK pathway activation in RBL-2H3 and HMC-1 cells. Conclusions: BIOGF1K attenuated the AD response, hence supporting its use as a promising and natural approach for treating AD.

• BMB Reports
• /
• 제50권12호
• /
• pp.640-646
• /
• 2017

Regulatory B cells, also well-known as IL-10-producing B cells, play a role in the suppression of inflammatory responses. However, the epigenetic modulation of regulatory B cells is largely unknown. Recent studies showed that the bromodomain and extra-terminal domain (BET) protein inhibitor JQ1 controls the expression of various genes involving cell proliferation and cell cycle. However, the role of BET proteins on development of regulatory B cells is not reported. In this study, JQ1 potently suppressed IL-10 expression and secretion in murine splenic and peritoneal B cells. While bromodomain-containing protein 4 (BRD4) was associated with $NF-{\kappa}B$ on IL-10 promoter region by LPS stimulation, JQ1 interfered the interaction of BRD4 with $NF-{\kappa}B$ on IL-10 promoter. In summary, BRD4 is essential for toll like receptor 4 (TLR4)-mediated IL-10 expression, suggesting JQ1 could be a potential candidate in regulating IL-10-producing regulatory B cells in cancer.

• 대한약리학회지
• /
• 제30권2호
• /
• pp.205-215
• /
• 1994

It is well known that chronic stimulation with CCK gives rise to growth of exocrine pancreas and to increased content of enzyme proteins in pancreas. However, littls Is known about changes of the secretory function of exocrine pancreas which has been chronically stimulated with CCK, especially about the responsiveness to secretagogues such as CCK, caerulein and carbachol. The present study was performed to investigate the effect of camostat on secretory profiles and the responsiveness to secretagogues of exocrine pancreas by observing in vitro amylase release stimulated by cholecystokinin-octapeptide(CCK-8) and carbachol in dispersed isolated pancreatic acini from camostat-treated rats for 4 or 10 days. The results summarized as follows : 1) The maximal effective concentration of CCK-8 in amylase release in the camostat treated group was greater than control group, but that of carbachol was not different between groups. 2) Analysis of the stimulated amylase release as the percentage of the maximal response revealed that camostat treatment caused right-shift of the dose-response curve of CCK-8. Camostat did not cause significant changes in the dose-response curve of carbachol. 3) There were considerable increases in the amylase release in the camostat-treated group, compared to the control when acini were stimulated with CCK-8 $10^{-9}\;M$ and carbaochol $10^{-6}\;M$, and higher concentrations. 4) There was a reverse correlation between the tissue content and the maximal release(percent of the total content) of amylase. These results suggest that chronic exposure of exocrine pancreas to increased endogenous CCK can enhance the responsiveness of exocrine enzyme secretion to secretagogues, especially at higher concentrations of CCK and carbachol.

• The Plant Pathology Journal
• /
• 제36권5호
• /
• pp.428-439
• /
• 2020

Erwinia pyrifoliae is a Gram-negative bacterial plant pathogen that causes black shoot blight in apple and pear. Although earlier studies reported the genome comparison of Erwinia species, E. pyrifoliae strains for such analysis were isolated in 1996. In 2014, the strain E. pyrifoliae EpK1/15 was newly isolated in the apple tree showing black shoot blight in South Korea. This study aimed to better understand the similarities and differences caused by natural variations at the genomic level between newly isolated E. pyrifoliae EpK1/15 and the strain Ep1/96, which were isolated almost 20 years apart. Several comparative genomic analyses were conducted, and Clusters of Orthologous Groups of proteins (COG) database was used to classify functional annotation for each strain. E. pyrifoliae EpK1/15 had similarities with the Ep1/96 strain in stress-related genes, Tn3 transposase of insertion sequences, type III secretion systems, and small RNAs. The most remarkable difference to emerge from this comparison was that although the draft genome of E. pyrifoliae EpK1/15 was almost conserved, Epk1/15 strain had at least three sorts of structural variations in functional annotation according to COG database; chromosome inversion, translocation, and duplication. These results indicate that E. pyrifoliae species has gone natural variations within almost 20 years at the genomic level, and we can trace their similarities and differences with comparative genomic analysis.

• Journal of Microbiology and Biotechnology
• /
• 제26권9호
• /
• pp.1613-1619
• /
• 2016

Francisella tularensis is a highly virulent pathogen of humans and other mammals. Moreover, F. tularensis has been designated a category A biothreat agent, and there is growing interest in the development of a protective vaccine. In the present study, we determine the in vitro and in vivo immune responses of a subunit vaccine composed of recombinant peptides Tul4 and FopA from epitopes of the F. tularensis outer membrane proteins. The recombinant peptides with adjuvant CpG induced robust immunophenotypic change of dendritic cell (DC) maturation and secretion of inflammatory cytokines (IL-6, IL-12). In addition, the matured DCs enabled ex vivo proliferation of naive splenocytes in a mixed lymphocyte reaction. Lastly, we determined the in vivo immune response by assessment of antibody production in C57BL/6 mice. Total IgG levels were produced after immunization and peaked in 6 weeks, and moreover, Tul4-specific IgG was confirmed in the mice receiving peptides with or without CpG. Based on these results, we concluded that the recombinant peptides Tul4 and FopA have immunogenicity and could be a safe subunit vaccine candidate approach against F. tularensis.

• 한국미생물·생명공학회지
• /
• 제34권1호
• /
• pp.1-6
• /
• 2006

Harmful algal blooms (HABs or red tides), caused by uncontrolled proliferation of marine phytoplankton, impose a severe environmental problem and occasionally threaten even public health. We sequenced the genome of an EPS-producing marine bacterium Hahella chejuensis that produces a red pigment with the lytic activity against red-tide dinoflagellates at parts per billion level. H. chejuensis is the first sequenced species among algicidal bacteria as well as in the order Oceanospirillales. Sequence analysis indicated a distant relationship to the Pseudomonas group. Its 7.2-megabase genome encodes basic metabolic functions and a large number of proteins involved in regulation or transport. One of the prominent features of the H. chejuensis genome is a multitude of genes of functional equivalence or of possible foreign origin. A significant proportion (${\sim}23%$) of the genome appears to be of foreign origin, i.e. genomic islands, which encode genes for biosynthesis of exopolysaccharides, toxins, polyketides or non-ribosomal peptides, iron utilization, motility, type III protein secretion and pigment production. Molecular structure of the algicidal pigment was determined to be prodigiosin by LC-ESI-MS/MS and NMR analyses. The genomics-based research on H. chejuensis opens a new possibility for controlling algal blooms by exploiting biotic interactions in the natural environment and provides a model in marine bioprospecting through genome research.

• Journal of Microbiology and Biotechnology
• /
• 제23권8호
• /
• pp.1116-1122
• /
• 2013

Cell line development is the most critical and also the most time-consuming step in the production of recombinant therapeutic proteins. In this regard, a variety of vector and cell engineering strategies have been developed for generating high-producing mammalian cells; however, the cell line engineering approach seems to show various results on different recombinant protein producer cells. In order to improve the secretory capacity of a recombinant tissue plasminogen activator (t-PA)-producing Chinese hamster ovary (CHO) cell line, we developed cell line engineering approaches based on the ceramide transfer protein (CERT) and X-box binding protein 1 (XBP1) genes. For this purpose, CERT S132A, a mutant form of CERT that is resistant to phosphorylation, and XBP1s were overexpressed in a recombinant t-PA-producing CHO cell line. Overexpression of CERT S132A increased the specific productivity of t-PA-producing CHO cells up to 35%. In contrast, the heterologous expression of XBP1s did not affect the t-PA expression rate. Our results suggest that CERT-S132A-based secretion engineering could be an effective strategy for enhancing recombinant t-PA production in CHO cells.