• East Asian Journal of Business Economics (EAJBE)
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• v.7 no.1
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• pp.1-16
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• 2019

Purpose - For the development of fresh food shopping malls, consumers should continue to experience loyalty and favorability for the company's products or brands, and this should lead directly to purchase so that active word-ofmouth and recommendation should be encouraged. Therefore, the purpose of this study is to investigate the effect of e-service quality and e-ERM on e-loyalty with customer satisfaction and commitment as mediators. Research design, data, and methodology - This study was conducted by sample survey method on 320 online customers who have experience in using major online fresh food shopping malls for more than one year. Data analysis methods were frequency analysis, confirmatory factor analysis, reliability analysis, correlation analysis, and structural equation model analysis. Result - Hypothesis 1 through Hypothesis 7 were all supported. The results of this study suggest that e-service quality and e-CRM of online fresh food shopping malls have a significant effect on satisfaction and commitment. Therefore, the conclusion has been derived that the focus of this study, that such satisfaction and commitment have a significant effect on e-customer loyalty. has been supported theoretically and empirically. Conclusion - This study suggests that studies on customer loyalty based on activation commerce factors related to fresh food in online shopping malls will be an index that can reflect on customer's needs corresponding with future trends of not only online shopping malls but also offline shopping malls.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1238-1244
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• 2014

Dephosphocoenzyme A (CoaE) catalyzes the last step in the biosynthesis of the cofactor coenzyme A. In this study, we report the identification and application of CoaE from Stretomyces peucetius ATCC27952. After expression of coaE, the protein was found to have a molecular mass of 28.6 kDa. Purification of the His-tagged fused CoaE protein was done by immobilized metal-affinity chromatography, and then in vitro enzymatic coupling assay was performed. The increasing NADH consumption with time shed light on the phosphorylating activity of CoaE. Furthermore, the overexpression of coaA and coaE independently under the $ermE^*$ promoter in the doxorubicin -producing wild type strain, resulted in 1.4- and 1.5-fold enhancements in doxorubicin production, respectively. In addition, the overexpression of both genes together showed a 2.1-fold increase in doxorubicin production. These results established a positive role for secondary metabolite production from Streptomyces peucetius.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.211-218
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• 2023

A cryptic plasmid (pTH32) was characterized from Tetragenococcus halophilus 32, an isolate from jeotgal, Korean traditional fermented seafood. pTH32 is 3,198 bp in size with G+C content of 35.84%, and contains 4 open reading frames (ORFs). orf1 and orf2 are 456 bp and 273 bp in size, respectively, and their translation products showed 65.16% and 69.35% similarities with RepB family plasmid replication initiators, respectively, suggesting the rolling-circle replication (RCR) mode of pTH32. orf3 and orf4 encodes putative hypothetical protein of 186 and 76 amino acids, respectively. A novel Tetragenococcus-Escherichia coli shuttle vector, pMJ32E (7.3 kb, Em^r), was constructed by ligation of pTH32 with pBluescript II KS(+) and an erythromycin resistance gene (ErmC). pMJ32E successfully replicated in Enterococcus faecalis 29212 and T. halophilus 31 but not in other LAB species. A pepA gene, encoding aminopeptidase A (PepA) from T. halophilus CY54, was successfully expressed in T. halophilus 31 using pMJ32E. The transformant (TF) showed higher PepA activity (49.8 U/mg protein) than T. halophilus 31 cell (control). When T. halophilus 31 TF was subculturd in MRS broth without antibiotic at 48 h intervals, 53.8% of cells retained pMJ32E after 96 h, and only 2.4% of cells retained pMJ32E after 14 days, supporting the RCR mode of pTH32. pMJ32E could be useful for the genetic engineering of Tetragenococcus and Enterococcus species.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.352-358
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• 2016

The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2”)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.87-92
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• 2005

Pronase, a protease produced for commercial purpose by Streptomyces griseus, was composed of serine protease, alkaline protease, aminopeptidase and carboxypeptidase complex, and it has been widely used as anti-inflammatory drugs for human therapy. In this study, we developed a new integration vector, pHJ101 derived from pSET152, containing strong promoter, ermE, to overexpress a certain protease gene. Specific PCR primers for cloning of sprA (a gene for S. griseus protease A) and sprB (a gene for S. griseus protease B) genes were designed from the basis of nucleotide sequence in databases and amplified by PCR. Plasmid pHJ201 and pHJ202 were constructed by inserting of amplified each gene in a vector pHJ101. S. griseus HA and S. griseus HB were respectively obtained by conjugal process of a parent strain, S. griseus IFO 13350 with the recombinant Escherichia coli harboring plasmid pHJ201 or pHJ202. When protease activity was measured in flask cultivation, produced protease levels of S. griseus HA and S. griseus HB increased about 5.3 times and 5 times, respectively, more than that of parent strain. And, the constructed integrating plasmid pHJ101 was applicable for overexpression of a certain gene in Streptomyces sp.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.132-137
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• 2010

The skc gene encoding streptokinase (SK) with a molecular mass of approximately 47.4 kDa was cloned from Streptococcus equisimilis ATCC 9542 and heterologously overexpressed in Streptomyces lividans TK24 and E. coli using various strong promoters. When the promoter for sprT [Streptomyces griseus trypsin (SGT)] was used in the host S. lividans TK24, a 47.4-kDa protein was detected along with a smaller hydrolyzed protein (44 kDa), suggesting that posttranslational hydrolysis had occurred as has been reported in other expression systems. The casein/plasminogen plate assay revealed that the plasmid construct containing the SGT signal peptide was superior to that containing the SK signal peptide in terms of SK production. Maximal production of SK was calculated to be about 0.25 unit/ml of culture broth, a value that was five times higher than that obtained with other expression systems using ermE and tipA promoters in the same host. When the skc gene was expressed in E. coli BL21(${\Delta}DE3$)pLys under the control of the T7 promoter, a relatively large amount of SK was expressed in soluble form without hydrolysis. SK activity in E. coli/pET28a-$T7_pSK_m$ was more than 2 units/ml of culture broth, even though about half of the expressed protein formed an inactive inclusion body.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.367-377
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• 2009

Halitosis is a generally accepted marker of diseases in the oral cavity and of systemic and gastrointestinal disorders. Based on these authors' previous findings (that (1) there is a close association between H. pylori infection and halitosis; (2) Korea red ginseng may suppress the colonization of H. pylori, fight H. pylori-induced cytotoxicity, and impose significant anti-inflammatory actions in patients with chronic gastritis; and (3) H. pylori infection is linked with the generation of significant levels of volatile sulfur compounds (VSCs), and the levels of VSCs correlate significantly with H. pylori-associated mucosal damages), in the current study, the authors documented the molecular mechanisms of Korea red ginseng's efficacy in ameliorating halitosis. When the RAW 264.7 cells were treated with the $H_2S$ releasing compound NaHS, the mRNA expression of cystathionine ${\gamma}$-lyase (CSE), IL-6, COX-2, and iNOS were more significantly induced compared with the vehicle-treated group. The cytoskeletal components of ezrin's and moesin's mRNA expressions were elevated by NaHS treatment accompanied by the activation of MAPK, p38, and ERK. Korea red ginseng pretreatment reduced both the NaHS-induced CSE expression and the proinflammatory genes (e.g., IL-6, COX-2, and iNOS) in a concentration-dependent manner. The ERM expression and the phosphorylation of p38 were also significantly reduced by Korea-red-ginseng pretreatment. Overall, Korea red ginseng pretreatment imposed significant anti-inflammatory effects through the downregulation of the NaHS-triggered proinflammatory gene expression, CSE, and ERM mRNA expression. Korea red ginseng could thus be said to be a key remedy of halitosis and to be effective in relieving gastric inflammation.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1226-1231
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• 2014

The rare actinomycete Pseudonocardia autotrophica was previously shown to produce a solubility-improved toxicity-reduced novel polyene compound named $\underline{N}ystatin$-like $\underline{P}seudonocardia$ $\underline{P}olyene$ (NPP). The low productivity of NPP in P. autotrophica implies that its biosynthetic pathway is tightly regulated. In this study, $wblA_{pau}$ was isolated and identified as a novel negative regulatory gene for NPP production in P. autotrophica, which showed approximately 49% amino acid identity with a global antibiotic down-regulatory gene, wblA, identified from various Streptomycetes species. Although no significant difference in NPP production was observed between P. autotrophica harboring empty vector and the S. coelicolor wblA under its native promoter, approximately 12% less NPP was produced in P. autotrophica expressing the wblA gene under the strong constitutive $ermE^*$ promoter. Furthermore, disruption of the $wblA_{pau}$ gene from P. autotrophica resulted in an approximately 80% increase in NPP productivity. These results strongly suggest that identification and inactivation of the global antibiotic down-regulatory gene wblA ortholog are a critical strategy for improving secondary metabolite overproduction in not only Streptomyces but also non-Streptomyces rare actinomycete species.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.116-120
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• 2006

We constructed four recombinant plasm ids to enhance the production of clavulanic acid (CA) in Streptomyces clavuligerus NRRL3585: (1) pIBRHL1, which includes ccaR, a pathway-specific regulatory gene involved in cephamycin C and CA biosynthesis; (2) pIBRHL2, containing claR, again a regulatory gene, which controls the late steps of CA biosynthesis; (3) pGIBR containing afsR-p, a global regulatory gene from Streptomyces peucetius; and (4) pKS, which harbors all of the genes (ccaR/ claR/ afsR-p). The plasmids were expressed in S. clavuligerus NRRL3585 along with the $ermE^*$ promoter. All of them enhanced the production of CA; 2.5-fold overproduction for pIBRHL1, 1.5-fold for pIBRHL2, 1.6-fold for pGIBR, and 1.5-fold for pKS compared to the wild type.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.295-298
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• 2006

Actinomycetes are ubiquitous Gram-positive soil bacteria and a group of the most important industrial microorganisms for the biosynthesis of many valuable secondary metabolites as well as the source of various bioconversion enzymes. Cytochrome P450 hydroxylase (CYP), a hemebinding protein, is known to be involved in the modification of various natural compounds, including polyketides, fatty acids, steroids, and some aromatic compounds. Previously, six different novel CYP genes were isolated from a rare actinomycetes called Sebekia benihana, and they were completely sequenced, revealing significant amino acid similarities to previously known CYP genes involved in Streptomyces secondary metabolism. In the present study, these six CYP genes were functionally expressed in Streptomyces lividans, using an $ermE^{*}$ promoter-containing Streptomyces expression vector. Among six CYP genes, two S. benihana CYP genes (CYP503 and CYP504) showed strong hydroxylation activities toward 7-ethoxycoumarin. Furthermore, the recombinant S. lividans containing both the S. benihana CYP506-ferredoxin genes as well as the S. coelicolor feredoxin reductase gene also demonstrated cyclosporin A hydroxylation activity, suggesting potential application of actinomycetes CYPs for the biocatalysts of natural product bioconversion.