• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.895-908
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• 2023

Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the current study, metal-resistant Raoultella ornithinolytica was isolated from metal-contaminated samples collected from the Tanjaro River, located southwest of Sulaymaniyah, Iraq. R. ornithinolytica was identified by partial amplification of 16S rRNA. The uptake potency of heavy metals was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and indicated that R. ornithinolytica removed 67, 89, 63.4, 55.6, 56.5, 65, and 61.9% of Cd, Pb, Cr, Ni, Zn, Co, and Fe, respectively. These removal rates were influenced by temperature, pH, and contact time; at 35℃ and pH 5 with a change in the incubation time, the reduction rate improved from 89 to 95% for Pb, from 36.4 to 45% for Cu, and from 55.6 to 64% for Ni. Gene analysis indicated that R. ornithinolytica contained pbrT, chrB, nccA, iroN, and czcA genes, but the pcoD gene was absent. Energy-dispersive X-ray spectroscopy (EDS) images showed evidence of metal ion binding on the cell wall surface with different rates of binding. Transmission electron microscopy (TEM) detected different mechanisms for metal particle localization; cell surface adsorption was the main mechanism for Pb, Zn, and Co uptake, while Cd, Ni, and Fe were accumulated inside the cell. The current study describes, for the first time, the isolation of R. ornithinolytica from metal-contaminated water, which can be used as an eco-friendly biological expedient for the remediation and detoxification of metals from contaminated environments.

• Fisheries and Aquatic Sciences
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• 제26권2호
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• pp.158-168
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• 2023

The global output of Pyropia yezoensis (dried seaweed or laver, also called 'Gim' in Korea) has been reduced over the half-decade due to the wide spread of red rot disease, a serious algal disease affecting P. yezoensis. Recently, Gold 1 (G1), which is a resistant strain of P. yezoensis to red rot disease, was developed and commercialized in South Korea, yet its physiological activity has not been investigated. In this study, a comparative study was performed on G1 and commercially available strain of P. yezoensis (CP) for their antioxidative activities. Aqueous extract of G1 showed more marked 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity compared to that of CP. In 293T cells, antioxidant activity against H₂O₂-induced reactive oxygen species (ROS) formation was only observed in G1 extract. In addition, G1 extract showed more potent inhibitory effect on H₂O₂-induced apoptotic cell death than CP extract, as examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and fluorescence microscopy. Expression levels of various apoptosis-related genes, including B-cell lymphoma 2-associated X protein, p53, capase-3, and inflammatory cytokines, in H₂O₂-treated cells were significantly decreased by the treatment of G1. Taken together, the present study suggests that a new strain of red seaweed G1 can recover oxidative stress effectively by improving the imbalance of ROS generation and has a potential to be used a functional ingredient as an antioxidant source.

• Journal of Ginseng Research
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• 제47권3호
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• pp.420-428
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• 2023

Background: Ginsenoside F2 (GF2), a minor component of Panax ginseng, has been reported to possess a wide variety of pharmacological activities. However, its effects on glucose metabolism have not yet been reported. Here, we investigated the underlying signaling pathways involved in its effects on hepatic glucose. Methods: HepG2 cells were used to establish insulin-resistant (IR) model and treated with GF2. Cell viability and glucose uptake-related genes were also examined by real-time PCR and immunoblots. Results: Cell viability assays showed that GF2 up to 50 μM did not affect normal and IR-HepG2 cell viability. GF2 reduced oxidative stress by inhibiting phosphorylation of the mitogen-activated protein kinases (MAPK) signaling components such as c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK, and reducing the nuclear translocation of NF-κB. Furthermore, GF2 activated PI3K/AKT signaling, upregulated the levels of glucose transporter 2 (GLUT-2) and GLUT-4 in IR-HepG2 cells, and promoted glucose absorption. At the same time, GF2 reduced phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression as well as inhibiting gluconeogenesis. Conclusion: Overall, GF2 improved glucose metabolism disorders by reducing cellular oxidative stress in IR-HepG2 cells via MAPK signaling, participating in the PI3K/AKT/GSK-3β signaling pathway, promoting glycogen synthesis, and inhibiting gluconeogenesis.

• Genomics & Informatics
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• 제21권3호
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• pp.35.1-35.12
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• 2023

The Bacillus cereus group, also known as B. cereus sensu lato (B. cereus s.l.), is composed of various Bacillus species, some of which can cause diarrheal or emetic food poisoning. Several emerging highly heat-resistant Bacillus species have been identified, these include B. thermoamylovorans, B. sporothermodurans, and B. cytotoxicus NVH 391-98. Herein, we performed whole genome analysis of two thermotolerant Bacillus sp. isolates, Bacillus sp. B48 and Bacillus sp. B140, from an omelet with acacia leaves and fried rice, respectively. Phylogenomic analysis suggested that Bacillus sp. B48 and Bacillus sp. B140 are closely related to B. cereus and B. thuringiensis, respectively. Whole genome alignment of Bacillus sp. B48, Bacillus sp. B140, mesophilic strain B. cereus ATCC14579, and thermophilic strain B. cytotoxicus NVH 391-98 using the Mauve program revealed the presence of numerous homologous regions including genes responsible for heat shock in the dnaK gene cluster. However, the presence of a DUF4253 domain-containing protein was observed only in the genome of B. cereus ATCC14579 while the intracellular protease PfpI family was present only in the chromosome of B. cytotoxicus NVH 391-98. In addition, prophage Clp protease-like proteins were found in the genomes of both Bacillus sp. B48 and Bacillus sp. B140 but not in the genome of B. cereus ATCC14579. The genomic profiles of Bacillus sp. isolates were identified by using whole genome analysis especially those relating to heat-responsive gene clusters. The findings presented in this study lay the foundations for subsequent studies to reveal further insights into the molecular mechanisms of Bacillus species in terms of heat resistance mechanisms.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.455-462
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• 2023

Since 2015, countries in the Sahel region have implemented large-scale seasonal malaria chemoprevention (SMC). However, the mass use of sulfadoxine-pyrimethamine (SP) plus amodiaquine impacts the genetic diversity of malaria parasites and their sensitivity to antimalarials. This study aimed to describe and compare the genetic diversity and SP resistance of Plasmodium falciparum strains in Mali and Niger. We collected 400 blood samples in Mali and Niger from children aged 3-59 months suspected of malaria. Of them, 201 tested positive (Niger, 111, 55.2%; Mali, 90, 44.8%). Polymorphism of merozoite surface protein 1 (msp1) genetic marker showed 201 allotypes. The frequency of the RO33 allotype was significantly higher in Niger (63.6%) than in Mali (39.3%). There was no significant difference in the frequency of the K1 and MAD20 allotypes between the 2 countries. The multiplicity of infection was 2 allotypes per patient in Mali and one allotype per patient in Niger. The prevalence of strains with the triple mutants Pfdhfr51I/Pfdhfr59R/Pfdhps436A/F/H and Pfdhfr51I/Pfdhfr59R/Pfdhps437G was 18.1% and 30.2%, respectively, and 7.7% carried the quadruple mutant Pfdhfr51I/Pfdhfr59R/Pfdhps436A/F/H/Pfdhps437G. Despite the significant genetic diversity of parasite populations, the level of SP resistance was comparable between Mali and Niger. The frequency of mutations conferring resistance to SP still allows its effective use in intermittent preventive treatment in pregnant women and in SMC.

• 대한약침학회지
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• 제26권4호
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• pp.307-318
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• 2023

Objectives: Bacterial biofilm is regarded as a significant threat to the production of safe food and the arise of antibiotic-resistant bacteria. The objective of this investigation is to evaluate the quorum sensing inhibitory effect of Nepeta curviflora methanolic extract. Methods: The effectiveness of the leaves at sub-inhibitory concentrations of 2.5, 1.25, and 0.6 mg/mL on the virulence factors and biofilm formation of P. aeruginosa was evaluated. The effect of N. curviflora methanolic extract on the virulence factors of P. aeruginosa, including pyocyanin, rhamnolipid, protease, and chitinase, was evaluated. Other tests including the crystal violet assay, scanning electron microscopy (SEM), swarming motility, aggregation ability, hydrophobicity and exopolysaccharide production were conducted to assess the effect of the extract on the formation of biofilm. Insight into the mode of antiquorum sensing action was evaluated by examining the effect of the extract on the activity of N-Acyl homoserine lactone (AHL) and the expression of pslA and pelA genes. Results: The results showed a significant attenuation in the production of pyocyanin and rhamnolipid and in the activities of protease and chitinase enzymes at 2.5 and 1.25 mg/mL. In addition, N. curviflora methanolic extract significantly inhibited the formation of P. aeruginosa biofilm by decreasing aggregation, hydrophobicity, and swarming motility as well as the production of exopolysaccharide (EPS). A significant reduction in AHL secretion and pslA gene expression was observed, indicating that the extract inhibited quorum sensing by disrupting the quorum-sensing systems. The quorum-sensing inhibitory effect of N. curviflora extract appears to be attributed to the presence of kaempferol, quercetin, salicylic acid, rutin, and rosmarinic acid, as indicated by LCMS analysis. Conclusion: The results of the present study provide insight into the potential of developing anti-quorum sensing agents using the extract and the identified compounds to treat infections resulting from quorum sensing-mediated bacterial pathogenesis.

• Journal of Veterinary Science
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• 제25권3호
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• pp.39.1-39.11
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• 2024

Importance: Salmonella outbreaks linked to poultry meat have been reported continuously worldwide. Therefore, Salmonella contamination of poultry meats in slaughterhouses is one of the critical control points for reducing disease outbreaks in humans. Objective: This study examined the carry-over contamination of Salmonella species through the entire slaughtering process in South Korea. Methods: From 2018 to 2019, 1,097 samples were collected from the nine slaughterhouses distributed nationwide. One hundred and seventeen isolates of Salmonella species were identified using the invA gene-specific polymerase chain reaction, as described previously. The serotype, phylogeny, and antimicrobial resistance of isolates were examined. Results: Among the 117 isolates, 93 were serotyped into Salmonella Mbandaka (n = 36 isolates, 30.8%), Salmonella Thompson (n = 33, 28.2%), and Salmonella Infantis (n = 24, 20.5%). Interestingly, allelic profiling showed that all S. Mbandaka isolates belonged to the lineage of the sequence type (ST) 413, whereas all S. Thompson isolates were ST292. Moreover, almost all S. Thompson isolates (97.0%, 32/33 isolates) belonging to ST292 were multidrug-resistant and possessed the major virulence genes whose products are required for full virulence. Both serotypes were distributed widely throughout the slaughtering process. Pulsed-field gel electrophoretic analysis demonstrated that seven S. Infantis showed 100% identities in their phylogenetic relatedness, indicating that they were sequentially transmitted along the slaughtering processes. Conclusions and Relevance: This study provides more evidence of the carry-over transmission of Salmonella species during the slaughtering processes. ST292 S. Thompson is a potential pathogenic clone of Salmonella species possibly associated with foodborne outbreaks in South Korea.

• 식물병연구
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• 제18권4호
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• pp.317-323
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• 2012

본 연구는 국내 고추 주산지의 P. capsici의 균주에 대한 병원성과 균주별 역병 저항성 유전 양식을 구명하고자 수행하였다. 이병성 재료 '#308'과 역병 저항성 재료 'CM334' 및 이들의 $F_1$, $F_2$ 그리고 'Kataguma'(Sakata Korea) 고추 총 5종의 공시 재료에 이천, 음성, 부안, 임실, 영양 지역에서 수집한 P. capsici 각각의 균주와 국립농업유전자원센터에서 분양받은 PA-159(KACC No. 40482)를 포함하여 총 6종의 고추 P. capsici 균주를 사용하여 접종하였다. 접종 농도는 $1{\times}10^5spores/ml$로 관주 접종하였고 이들의 기내 특성, 이병률, $F_2$ 후대 집단의 역병저항성 분리 기대비를 분석하였다. 이병성 재료 '#308'과 저항성 'CM334', $F_1$의 비분리세대는 균주별 군내 비교에서는 각각 고추 역병의 발병도는 4.94-5.00, 1.00-1.07, 1.01-1.08을 보여 P. capsici 균주별 군내 비교에서 공시재료간 역병 저항성 차이는 명확히 구분할 수 있다. 또한 $F_2$ 분리세대의 역병 발병도의 경향은 1.79-2.31을 보여 P. capsici 군내 비교의 차이가 없고 저항성과 이병성 재료간에 유의한 차이를 보여 본 연구에서 사용된 6종의 P. capsici 균주 모두 역병 저항성 검정을 위한 균주로 활용 가능한 것으로 나타났다. 하지만 $F_2$ 분리세대의 균주별 군간 비교에서 PA-159 균주를 중심으로 이천 균주, 부안 균주, 임실 균주가 포함된 집단과 이보다 높은 병원성을 지닌 영양 균주와 음성 균주로 구분되었다. 각 균주별 $F_2$ 세대의 역병 저항성에 대한 분리 기대비를 분석하였는데, PA-159 균주는 3:1 또는 9:3:3:1의 분리비를 보여 1-2개의 유전자가 관여하는 것으로 나타났다. 반면 음성 균주와 영양 균주는 11:5, 이천 균주는 12:3:1의 분리비를 보여 유전자간 상호작용이 있는 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제34권4호
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• pp.342-351
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• 2006

병원내 항생제 다제 내성을 일으키는 CTX-M형 ESBL을 생성하는 E. coli와 Klebsielia pneumoniae의 생성현황을 조사하고 이들 균주로 인한 감염증치료와 역학적 조사연구에 도움이 되고자 효소의 유전형을 규명하였다. 2005년 7월-12월에 부산에 소재하고 있는 2개의 종합병원에서 분리된 E. coli와 K. pneumoniae 각각 153주, 52주를 수집하였다. 그 중에서 ESBL을 생성 하는 균주를 검출하기 위해 Double disk synergy test를 시행하여서 E. coli 23주와 K. pneumoniae 13주를 분리하였다. 균주의 동정은 Vitek system GNI card(bioMerieux Vitek Inc., Hazelwood, Mo., U.S.A.)로 확인하였고, 항생제감수성시험은 disk diffusion method 와 agar dilution method를 사용하였다. 분리된 균주들의 내성을 일으키는 ESBL유전형을 규명하기 위하여 Isoelectric focusing(IEF), polymerase chain reaction test, DNA sequencing을 시행하였다. A병원의 13주와 B병원의 10주로 총 23주의 E. coli(15.0%)와 A병원의 7주와 B병원의 6주로 K. pneumoniae 13주(25.0%)가 double disk synergy test 양성으로 ESBL 생성균주로 판정하였다. ESBL 생성 36균주를 대상으로 bla$_{TEM}$, bla$_{SHV}$, bla$_{CTX-M}$ 유전자 검출을 위한 PCR을 시행한 결과 bla$_{TEM}$ 유전자는 13주(36.1%), bla$_{SHV}$ 유전자는 13주(36.1%), bla$_{CTX-M}$ 유전자는 32주(88.9%)가 양성반응을 보여서 bla$_{CTX-M}$ 유전자를 가진 균주가 가장 많이 나타났다. 그리고, bla$_{TME}$, bla$_{SHV}$ 두 가지 유전자를 가지고 있는 균주는 1주(2.8%)만 나타났고 bla$_{TEM}$, bla$_{CTX-M}$두 가지 유전자를 가지고 있는 균주는 9주(25.0%), bla$_{SHV}$, bla$_{CTX-M}$ 두 가지 유전자를 가지고 있는 균주가 10주(27.8%)로 나타나 bla$_{CTX-M}$을 포함하는 복합유전자가 많이 증가함을 알 수 있었다. 또한 CTX-M형 ESBL을 생성하는 E. coli와 K. pneumoniae에 대한 cefutaxime의 MIC는 256 $\mu$g/m1 이상으로 ceftazidime의 16-256 $\mu$g/mL 이상보다 높은 분포를 보였다. 즉, CTX-M형 ESBL 유전자를 지닌 균주에 대한 cefotaxim의 MIC는 ceftazidime의 MIC에 비해서 상대적으로 높은 양상을 보였다. 이러한 결과는 국내의 대학병원 뿐 만 아니라 일반종합병원에서도 CTX-M형 ESBL 생성 E. coli와 K. pneumoniae가 존재하며 확산 중임을 시사한다. 앞으로 CTX-M형 ESBL의 만연과 변종 CTX-M형 ESBL의 출연을 감시하기 위한 정기적인 연구와 조사가 필요한 것으로 생각한다.

• 한국잡초학회지
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• 제18권3호
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• pp.205-213
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• 1998

세계적으로 중요한 식량자원인 감자에 제초제 저항성 형질을 도입한다면, 노지재배가 가능하여 노동력과 인건비를 줄일 수 있을 뿐만 아니라 비닐멀칭 방법의 부산물인 폐비닐에 의한 환경오염을 줄일 수 있는 매우 효과적인 방법이다. 그러나 형질전환식물체의 선발시 일반적으로 사용해온 항생제 내성 표지유전자는 효과적으로 형질전환체를 선발할 수 있는 장점을 가지나 항생제 내성 표지유전자들이 환경중에 노출되었을 때의 안전성 문제, 그리고 일반 소비자들이 항생제 표지유전자를 이용한 형질전환체에 대해 거부감이 느껴지게 할 수 있다는 문제점이 존재한다. 이러한 문제점들은 항생제 내성 표지유전자를 제거하거나 새로운 표지유전자로 대체하는 방법을 사용하여 해결할 수 있을 것으로 생각된다. 따라서 본 실험의 목적은 비선택성 제초제 bialaphos에 저항성을 가지는 phosphinothricin acetyltransferase(PAT) gene을 감자에 도입하는데 있어 항생제 표지 유전자를 사용하지 않는 선발체계를 개발하고자 하였다. 감자 식물체의 재분화는 IBA 0.1mg/L + BA 0.5mg/L를 첨가한 MS배지에서 하였다. 또한 형질전환을 위해 단독 PAT 유전자만을 가지는 pDY502 vector를 재조합하였으며, 재조합된 vector들은 disarmed 된 Agrobacterium MP90에 도입하여 감자의 형질전환에 이용하였다. 형질전환은 강자의 잎과 줄기절편체를 상기 실험에서 재 조합된 vector를 함유한 A. tumefaciens MP90과 공동배양하는 방법으로 수행하였다. PAT 유전자를 표지유전자로 이용하여 bialaphos에 저항성을 가진 감자를 개발하고자 다양한 농도의 bialaphos를 함유한 재분화배지에 감자절편체를 치상하여 내성을 조사한 결과 대조구의 감자절편체가 모두 고사하는 bialaphos 5mg/L를 선발조건으로 하였다. 이와 같은 선발 조건에서 Agrobacterium과 공동 배양한 절편체를 선발배지에 치상한 후 3-4주 정도가 경과하면 shoot가 유기되었으며, 선발배지에서 유기된 shoot의 정단부위를 lcm정도로 잘라 bialaphos가 20mg/L 첨가된 선발배지로 옮겨 2차 선발을 하였다. 형질전환체의 확인은 2차 선발배지에서 선발된 식물체를 대상으로 하였으며, 먼저 PCR반응을 이용하여 도입 유전자의 증폭을 확인하였고, Southern blot을 실시하여 유전자의 도입을 확인하였다. 따라서 PAT 유전자를 감자 형질전환의 표지유전자로 활용할 수 있었으며, 아울러 항생제 표지유전자가 없는 제초제 저항성 형질전환 감자를 획득할 수 있었다.