The aim of this study was to transfer the 18.5 kb gene clusters coding for 17 genes from Lactobacillus rhamnosus to Lactococcus lactis subsp. cremoris MG1363 in order to determine the effect of host on exopolysaccharide (EPS) production and to provide a model for studying the phosphorylation of proteins which are proposed to be involved in EPS polymerization. Lactobacillus rhamnosus RW-9595M and ATCC 9595 have 99% identical operons coding for EPS biosynthesis, produced different amounts of EPS (543 vs 108 mg/l). L. lactis subsp. cremoris MG1363 transformed with the operons from RW-9595M and ATCC 9595 respectively, produced 326 and 302 mg/l EPS in M17 containing 0.5% glucose. The tyrosine protein kinase transmembrane modulator (Wzd) was proposed to participate in regulating chain elongation of EPS polymers by interacting with the tyrosine protein kinase Wze. While Wzd was found in phosphorylated form in the presence of the phosphorylated kinase (Wze), no phosphorylated proteins were detected when all nine tyrosines of Wzd were mutated to phenylalanine. Lactococcus lactis subsp. cremoris could produce higher amounts of EPS than other EPS-producing lactococci when expressing genes from L. rhamnosus. Phosphorylated Wzd was essential for the phosphorylation of Wze when expressed in vivo.

myo-Inositol (MI)을 대사하여 다른 물질로 전환하는 미생물을 과수원 토양으로부터 분리하였다. 분리균 YB-46은 유일한 탄소원으로 MI이 첨가된 배지에서 성장하였고 16S rDNA 염기서열에 따라 Enterobacter 속의 균주로 추정되었다. Fosmid pCC1FOS 벡터를 사용하여 제조된 거대 유전체 은행으로부터 MI을 미지의 대사 물질로 전환하는 Escherichia coli 형질전환주를 선발하였다. 이로부터 플라스미드를 분리하고 삽입된 유전자의 일부 염기서열을 결정한 결과 336 아미노 잔기로 구성된 myo-inositol dehytrogenase (IolG)를 암호화하는 iolG 유전자가 발견되었다. 분리균 YB-46의 IolG는 E. aerogenes와 Bacillus subtilis의 IolG와 약 50% 수준의 상동성을 보였다. 카르복실 말단에 hexahistidine이 연결되도록 제조한 His-tagged IoG (HtIolG)의 유전자를 재조합 대장균에서 발현하여 균체 파쇄액으로부터 HtIolG를 정제하였다. 정제된 HtIolG는 $45^{\circ}C$와 pH 10.5에서 최대 활성을 보였고 MI과 D-glucose에 대한 활성이 가장 높았으며 D-chiro-inositol, D-mannitol 및 D-xylose에도 90% 이상의 활성을 보였다. 최적 반응조건에서 MI을 기질로 하여 반응 동력학적 계수를 측정한 결과 $K_m$과 $V_{max}$가 1.83 mM과 $0.724{\mu}mol/min/mg$로 확인되었다. HtIolG의 활성은 $Zn^{2+}$에 의해 1.7배 증가하였으며, $Co^{2+}$와 SDS에 의해서는 크게 감소하였다.

In this study, purification of cold-adapted protease from Janthinobacterium sp. was investigated. First, using gradient precipitation, protease was confirmed to be deposited in the 30-80% range of ammonium sulfate. Next, DEAE-Sepharose column was used for the binding of the protease under various conditions. The optimal binding condition was found to be pH 8.5 and flow rate of 30 ml/h. Under the optimal condition, the protease was purified with 29% recovery yield. This result can be useful for the purification of other cold-adapted protein.

Astaxanthin is one of the major carotenoids used in pigment has a great economical value in pharmaceutical markets, feeding, nutraceutical and food industries. This study was to increase the production of astaxanthin by co-expression with transformed Escherichia coli using six genes involved in the non-mevalonate pathway. Involved in the non-mevalonate biosynthetic pathway of the strain Kocuria gwangalliensis were cloned dxs, ispC, ispD, ispE, ispF, ispG, ispH and idi genes in order to increase astaxanthin production from the transformed E. coli. And co-expression with the genes to compared the amount of astaxanthin production. This engineered E. coli, containing both the non-mevalonate pathway gene and the astaxanthin biosynthesis gene cluster, produced astaxanthin at $1,100{\mu}g/g$ DCW (dry cell weight), resulting in approximately three times the production of astaxanthin.

환경친화적으로 항균성이 부여된 상처치료용 BC 드레싱을 개발하기 위한 기초연구로서, 은 이온에 대해 내성이 있으면서 은 나노입자를 생합성할 수 있는 초산균을 분리 및 동정하였다. 나아가 실험균주에 의한 BC 생산 조건을 조사하였다. 부패된 포도껍질로부터 분리된 G7 균주는 0.1 mM $AgNO_3$ 존재 하에서 생육할 수 있었으며, 16S rRNA 유전자의 염기서열 분석에 의거하여 Acetobacter intermdius로 동정되었다. 탄소원으로 2% glucose, 질소원으로 2% yeast extract, 보조탄소원으로 0.115% acetic acid가 함유된 배지에서 BC 생산량이 최대였다. 최적배지에서 생성된 BC의 구조적 특성을 FT-IR 및 XRD를 사용하여 조사한 결과, 생성된 BC는 전형적인 천연 cellulose와 동일한 cellulose I인 것으로 확인되었다. G7 균주를 0.1 mM $AgNO_3$ 가 함유된 최적 배지에서 배양한 결과, 배양액의 색깔이 적갈색으로 변하였으며, 이것은 은 나노입자가 생성되었음을 의미한다. 은 나노입자의 합성유무를 UV-Vis 스펙트럼 분석에 의하여 확인한 바, 425 nm에서 은 나노입자의 고유한 흡수스펙트럼이 관찰되었다. 또한, 생성된 BC를 주사전자현미경으로 관찰한 결과, 표면과 기공에 은 나노입자가 생성되어 있음을 재확인하였다.

본 연구에서는 해조류인 Umbraulva japonica의 표면에서 79개의 세균을 분리하였다. 16s rRNA 유전자 분석 결과, 주요 계통군은 Proteobacteria (74.69%), Actinobacteria (2.53%), Fimicute (2.53%), Bacteroidetes (20.25%)로 4개의 문(Phylum)이 관찰되었고, 7개의 강(Class), 13개의 목(Order), 17개의 과(Family), 31개의 속(Genus)을 확인하였다. 계통학적 분석 결과 3개의 균주가 표준균주와 97% 이하의 유사성을 보여 신속 또는 신종으로 보고될 가능성이 있다고 여겨지며, 향후 표준균주들과 함께 추가적인 신종 실험이 수행되어야 할 것으로 사료된다. 분리된 79 균주를 이용하여 인체 및 어류 병원균을 대상으로 항균 활성을 확인하였다. UJT7, UJT20, UJR17의 균체 현탁액이 Vibrio vulnificus에 대하여 항균 활성을 나타냈으며 UJR17의 균체 현탁액은 V. vulnificus와 Streptococcus parauberis에 항균 활성능이 있음을 확인하였다. UJT7은 Bacillus sp., UJT20과 UJR17은 Pseudomonas sp.로 확인되었으며 다양한 활용을 위한 추가적인 실험을 수행한 후 유익하게 이용 될 수 있을 것이라 사료된다.

The rapid increase in number and diversity of Extended Spectrum ${\beta}$-Lactamases (ESBLs) producing Enterobacteriaceae in natural aquatic environment is a major health concern worldwide. This study investigates abundance and distribution of ESBL producing multidrug resistant Enterobacteriaceae and molecular characterization of ESBL genes among isolates from highly polluted stretch of river Yamuna, India. Water samples were collected from ten different sites distributed across Delhi stretch of river Yamuna, during 2014-15. A total of 506 non duplicate Enterobacteriaceae isolates were obtained. Phenotypic detection of ESBL production and antibiotic sensitivity for 15 different antibiotics were performed according to CLSI guidelines (Clinical and Laboratory Standard Institute, 2015). A subset of ESBL positive Enterobacteriaceae isolates were identified by 16S rRNA gene and screened for ESBL genes, such as $bla_{CTX-M}$, $bla_{TEM}$ and $bla_{OXA}$. Out of 506 non-duplicate bacterial isolates obtained, 175 (34.58%) were positive for ESBL production. Susceptibility pattern for fifteen antibiotics used in this study revealed higher resistance to cefazolin, rifampicin and ampicillin. A high proportion (76.57%) of ESBL positive isolates showed multidrug resistance phenotype, with MAR index of 0.39 at Buddha Vihar and Old Delhi Railway bridge sampling site. Identification and PCR based characterization of ESBL genes revealed the prevalence of $bla_{CTX-M}$ and $bla_{TEM}$ genes to be 88.33% and 61.66%, respectively. Co-occurrence of $bla_{CTX-M}$ and $bla_{TEM}$ genes was detected in 58.33% of the resistant bacteria. The $bla_{OXA}$ gene was not detected in any isolates. This study highlights deteriorating condition of urban aquatic environment due to rising level of ESBL producing Enterobacteriaceae with multidrug resistance phenotype.

Among the carotenoid biosynthesis genes, crtI gene encodes the phytoene desaturase (CrtI) enzyme, and phytoene desaturase convert phytoene to lycopene. Phytoene desaturase is involved in the dehydrogenation reaction, in which four single bonds in the phytoene are introduced into a double bond, eliminating eight hydrogen atoms in the process. Phytoene desaturase is one of the key regulating enzyme in carotenoid biosynthetic pathway of various carotenoid biosynthetic organisms. The crtI gene in genomic DNA of Paracoccus haeundaensis was amplified and cloned into a T-vector to analyze the nucleotide sequence. As a result, the crtI gene coding for phytoene desaturase from P. haeundaensis consists of 1,503 base pairs encoding 501 amino acids residues. An expression plasmid containing the crtI gene was constructed, and Escherichia coli cells containing this plasmid produced the recombinant protein of approximately 55 kDa, equivalent to the molecular weight of phytoene desaturase. The expressed protein in cell lysate showed enzymatic activity similar to phytoene desaturase. Phytoene and lycopene were analyzed by HPLC and measured at wavelength of 280 nm and 470 nm, respectively. The $K_m$ values for phytoene and NADPH were $11.1{\mu}M$ and $129.3{\mu}M$, respectively.

현재 도시의 도시열섬현상을 완화시키는 방안으로 도시 녹화사업 및 연구가 주목 받고 있다. 이 연구에서는 질소고정균을 분리하고, 식물 성장에 미치는 영향을 확인했다. 먼저 질소고정 균을 분리하기 위해, 질소원이 없는 배지에서 enrichment를 실시했고, 질소원이 제한된 배지에서 높은 성장을 보인 colony를 분리하여 순수분리 했다. 순수 분리된 균은 ARA를 통해 acetylene이 90% 이상 감소되고, ethylene 생성을 통해 nitrogenase의 활성을 간접적으로 확인했다. 재현성이 확인된 Cedecea sp. MK7과 Enterobacter sp. Y8을 선별했다. 선별된 질소고정 균을 perennial rye grass의 성장에 적용한 결과 건조중량이 18.65 mg인 대조군에 비해 34.80 mg (186.60%)으로 증가한 것을 확인했다. 식물 성장 후, 질소고정 균이 접종된 토양의 미생물 군집 분석은 대조군과 유사했다. 따라서 본 연구에서는 도시녹화 시스템에 질소고정 균을 이용하여 식물 성장을 촉진한다면 그 효율이 증대될 것이다.

Non-typhoidal Salmonella is one of the main pathogens causing food-borne illness in humans, with up to 20% of cases resulting from consumption of pork products. Over the gastroenteritis signs, multidrug resistant Salmonella has arisen. In this study, pan-susceptible phenotypic strains of Salmonella enterica serotype Weltevreden recovered from pig production chain in Chiang Mai, Thailand during 2012-2014 were chosen for analysis. The aim of this study was to use whole genome sequencing (WGS) data with an emphasis on antimicrobial resistance gene investigation to assess their pathogenic potential and genetic diversity determination based on whole genome Multilocus Sequence Typing (wgMLST) to expand epidemiological knowledge and to provide additional guidance for disease control. Analyis using ResFinder 3.0 for WGS database tracing found that one of pan-susceptible phenotypic strain carried five classes of resistance genes: aminoglycoside, beta-lactam, phenicol, sulfonamide, and tetracycline associated genes. Twenty four and 36 loci differences were detected by core genome Multilocus Sequence Typing (cgMLST) and pan genome Multilocus Sequence Typing (pgMLST), respectively, in two matching strains (44/13 vs A543057 and A543056 vs 204/13) initially assigned by conventional MLST and Pulsed-field Gel Electrophoresis (PFGE). One hundread percent discriminant ability can be achieved using the wgMLST technique. WGS is currently the ultimate molecular technique for various in-depth studies. As the findings stated above, a new of "gold standard typing method era" for routine works in genome study is being set.

Human papillomavirus (HPV) plays a critical role in the development of cervical carcinoma. This study analyzed the efficiency of multiplex real-time PCR in detecting and identifying HPV genotypes in samples from women who visited a Korean hospital for checkups. Cervical swab specimens were obtained from women who attended a checkup at the Health Improvement Center of Hospital in Dankook University Cheonan, South Korea and were referred for an HPV genotyping test between January and September 2014. A total of 1703 cervical swab specimens were collected consecutively during this period. PCR results were compared with those of the traditional cytological assay for the same population. Among the 1,703 specimens, 19.91% were HPV positive, of which 14.50% indicated a single infection and 5.40% indicated multiple infections. However, cytology identified only 2.52% of positive cases, including 1.23% cases of atypical squamous cells of undetermined significance, 1% of low grade squamous intra-epithelial lesion, and 0.29% of high grade squamous intra-epithelial lesion. The rate of high-risk and low-risk HPV in the abnormal cytology group was 48 and 23, respectively, and 274 and 136 in the normal group, respectively. HPV types 56, 52, 43 were the most prevalent in that order. Our results confirm the efficiency of the HPV DNA assay for the detection of 28 different HPV genotypes with reasonable sensitivity. A screening strategy that comprises the HPV DNA assay and cytology would help overcome the low sensitivity of a cytological diagnosis.