Microbiologically Influenced Corrosion (MIC) occurring in underground buried pipes of API 5L X65 steel was investigated. MIC is a corrosion phenomenon caused by microorganisms in soil; it affects steel materials in wet atmosphere. The microstructure and mechanical properties resulting from MIC were analyzed by OM, SEM/EDS, and mapping. Corrosion of pipe cross section was composed of ① surface film, ② iron oxide, and ③ surface/internal microbial corrosive by-product similar to surface corrosion pattern. The surface film is an area where concentrations of C/O components are on average 65 %/ 16 %; the main components of Fe Oxide were measured and found to be 48Fe-42O. The MIC area is divided into surface and inner areas, where high concentrations of N of 6 %/5 % are detected, respectively, in addition to the C/O component. The high concentration of C/O components observed on pipe surfaces and cross sections is considered to be MIC due to the various bacteria present. It is assumed that this is related to the heat-shrinkable sheet, which is a corrosion-resistant coating layer that becomes the MIC by-product component. The MIC generated on the pipe surface and cross section is inferred to have a high concentration of N components. High concentrations of N components occur frequently on surface and inner regions; these regions were investigated and Na/Mg/Ca basic substances were found to have accumulated as well. Therefore, it is presumed that the corrosion of buried pipes is due to the MIC of the NRB (nitrate reducing bacteria) reaction in the soil.
Airborne bacteria are expected to float in the mushroom cultivation house, as it is a special environment with high humidity and high temperatures. Their concentration and diversity in the indoor air of the cultivation house could effect the health of farmers and the quality of mushrooms. To examine whether microbiota of airborne bacteria change from year to year, we measured the indoor temperature, humidity, and airborne bacterial concentration from mushroom cultivation houses located in six regions in Korea from 2020 to 2021, and isolated and identified airborne bacteria. The surveyed data were compared and the bacterial diversity of the 1st year and the 2nd year were determined. Based on the average temperature and humidity data surveyed, it can be seen that the temperature and humidity environment in the cultivation houses is such that bacteria can easily reproduce. It was observed that the temperature inside the cultivation houses tends to be higher or lower depending on the season and correlates with the temperature outside the cultivation houses. In the first year survey, 32 species of 20 genera were identified, and in the second year survey, bacteria belonging to 29 species of 22 genera were identified. Among them, the most detected species were all species belonging to the genus Bacillus. There were only three species (Bacillus altitudinis, Brevibacterium frigoritolerans, and Staphylococcus epidermidis) that were continuously isolated in common. Our results showed that the species of floating bacteria greatly vary from year to year even for the same cultivation houses.
목적 : 본 연구는 3-[{2-(Methacryloyloxy)ethyl}dimethylammonio]propane-1-sulfonate(DMAPS)로 기능화된 하이드로겔 콘택트렌즈를 개발하고, 이들의 물리적 물성과 단백질 및 세균의 흡착성을 조사하기 위한 것이다.
방법 : 하이드로겔 콘택트렌즈는 2-hydroxyethyl methacrylate(HEMA)와 ethylene glycol dimethacrylate (EGDMA)의 공중합에 의해 제조되었다. 연속적으로 벤조페논의 흡착과 DMAPS 단량체의 UV 유도 자유 라디칼 중합을 통해 양쪽 이온성이 기능화된 하이드로겔 콘택트렌즈를 제조하였다. 제조된 콘택트렌즈의 수분함량, 접촉각, 광학적 특성, 단백질 및 세균 흡착을 분석하였다.
결과 : DMAPS으로 기능화된 하이드로겔 콘택트렌즈는 더 높은 수분 함량, 향상된 표면 습윤성 및 우수한 가시광선 투과율을 가지고 있다. 더욱이, 하이드로겔 콘택트렌즈 표면에 양쪽 이온성의 DMAPS가 존재하기 때문에 라이소자임 및 알부민과 같은 단백질의 흡착이 낮아지고 세균 흡착이 대군에 비해 감소하였다. 결론 : 양쪽 이온성의 DMAPS을 이용한 하이드로겔 콘택트렌즈의 기능화 방법은 습윤성이 우수하고 단백질 및 세균 흡착을 감소시킬 수 있는 기능성 콘택트렌즈의 개발을 위한 전략을 제공할 수 있다.
In the current study, lactic lactic acid bacteria (LAB) Lactobacillus plantarum and Pediococcus pentosaceus were used as a mixed additive for the production of Orchardgrass silage by ensiled method and nutritional change fermentation ability and microbial content of experimental silages. The addition of LAB to Orchardgrass during ensiling process rapidly reduced the pH of the silages than the non-inoculated silages. In addition, the lactic and acetic acid content of silage was increased by LAB strains than the non-inoculated silages whereas butyric acid content was reduced in silage treated with LAB. A microbiological study revealed that higher LAB but lower yeast counts were observed in inoculated silages compared to non-inoculated silage. Overall data suggested that the addition of LAB stains could have ability to induce the fermentation process and improve the silage quality via increasing lactic acid and decreasing undesirable microbes.
Despite evidence that bacteria-sensing Toll-like receptors (TLRs) are activated in salivary gland tissues of Sjogren syndrome (SS) patients, the role of oral bacteria in SS etiopathogenesis is unclear. We previously reported that two SS-associated oral bacteria, Prevotella melaninogenica (Pm) and Rothia mucilagenosa (Rm), oppositely regulate the expression of major histocompatibility complex class I (MHC I) in human salivary gland (HSG) cells. Here, we elucidated the mechanisms underlying the differential regulation of MHC I expression by these bacteria. The ability of Pm and Rm to activate TLR2, TLR4, and TLR9 was examined using TLR reporter cells. HSG cells were stimulated by the TLR ligands, Pm, and Rm. The levels of MHC I expression, bacterial invasion, and viability of HSG cells were examined by flow cytometry. The hypoxic status of HSG cells was examined using Hypoxia Green. HSG cells upregulated MHC I expression in response to TLR2, TLR4, and TLR9 activation. Both Pm and Rm activated TLR2 and TLR9 but not TLR4. Rm-induced downregulation of MHC I strongly correlated with bacterial invasion and cell death. Rm-induced cell death was not rescued by inhibitors of the diverse cell death pathways but was associated with hypoxia. In conclusion, Pm upregulated MHC I likely through TLR2 and TLR9 activation, while Rm-induced hypoxia-associated cell death and the downregulation of MHC I, despite its ability to activate TLR2 and TLR9. These findings may provide new insight into how oral dysbiosis can contribute to salivary gland tissue damage in SS.
본 연구에서는 토지피복유형에 따른 바이오에어로졸 중 배양성 세균분포를 파악하기 위하여 충청북도 충주시에 위치한 3가지 유형을 대상으로 실시하였다. 토지피복에 따른 기상요소와 바이오에어로졸을 조사하여 측정지점별 미기상변화에 따른 세균 분포를 비교·분석할 수 있었다. 측정지점별 미기상 중 기온의 차이는 도시 숲 8.7℃, 수변 녹지 10.8℃, 도심지 10.2℃로 측정지점 중 도시 숲이 가장 낮은 기온 값을 보였으며, 상대습도는 도시 숲 61.8%, 수변 녹지 59.3%, 도심지 55.7%로 도시 숲이 가장 높은 것으로 분석되었다. 동정된 세균은 43속 99종으로 나타났다. 배양된 세균의 종 다양성 측면에서는 수변녹지 22속, 도시 숲 21속, 도심지 17속으로 조사되었으며, 종수의 경우 수변녹지 37종, 도심지 31종, 도시 숲 31종으로 나타났다. 3가지 유형의 측정지에 모두 존재하는 종은 Bacillus toyonensis와 Pseudarthrobacter oxydan으로 나타났으며, 또한 도시 숲과 수변녹지와 같은 녹지지역에서 존재하는 Herbiconiux flava종을 확인하였다. 측정지점별 미기상환경에 따른 세균농도의 변화를 분석한 결과 도시 숲 333CFU/㎥, 수변 녹지 287CFU/㎥, 도심지 173CFU/㎥ 순으로 나타났으며, 미기상 중 기온변화에 따른 측정지점별 농도변화는 미비하였다. 그러나 상대습도와 풍속은 농도변화와 유사한 경향을 보인 것으로 분석되었다. 따라서 본 연구에서는 토지피복유형에 따른 바이오에어로졸 중 배양성 세균의 분포 정도를 파악하여 측정지점별 바이오에어로졸의 특성을 비교·분석하여 추후 건강한 도시 관리 및 녹지조성의 기초자료를 제공하고자 하였다.
In this study, we investigated the effects of adding oat and lactic acid bacteria on the quality and functionality of yogurt. Yogurt was fermented with various lactic acid bacteria,; Lactobacillus acidophilus (LA), Lactobacillus delbrueckii sub. bulgaricus (LB), and Streptococcus thermophilussei (ST) and quality properties, β-glucan content, antioxidant activity were estimated. The quality of control and oat added yogurt (OY) showed significant differences depending on the type of strain and combination. The addition of oats significantly accelerated the lactic acid bacteria production, decreased the pH, and increased the titratable acidity and count of the viable cells compared to the control. Acid production was highest in ST, with the complex strains containing ST and LALBST showing high quality characteristics. The viscosity of oat yogurt was higher than that of the control group, and LALBST was also significantly higher than that of the control group. The β-glucan content of OY was 0.14-0.2%, and the organic acid content and antioxidant activity were also significantly increased by the addition of oats. As a result, it is thought that the addition of oats and a combination of lactic acid bacteria can be used for improving the quality and functionality of yogurt.
Bacillus velezensis HKB-1가 표고버섯 수확후배지 퇴비로부터 분리되었으며 고추역병균(Phythopthora capsici), 인삼모 잘록병균(Rhizoctonia solani), 고추탄저병균(Collectotrichum coccodes) 및 시들음병(Fusarium oxysporium)의 균사체 성장을 70% 이상 억제하는 항 진균 활성을 보였다. B. velezensis HKB-1은 표고버섯 수확후배지 퇴비물 추출물과 당밀 1% 첨가배지에서 다른 상업용 세균배지보다 10~100배 더 높은 세균증식률을 보였으며 고추 역병균의 균사체 생장을 90% 억제하였으며 고추생육 촉진효과 및 고추역병에 대하여 70% 이상의 방제효과가 있었다.
항균활성이 뛰어난 식물 정유를 이용하여 식품가공 기구 및 용기에 다양하게 사용되는 polyethylene과 stainless steel 표면에 형성된 식중독 6종의 biofilm 형성에 대한 억제 효과를 연구하였다. 식물 정유 20종의 식중독 미생물에 대한 항균활성을 disk diffusion 방법으로 평가한 결과 cinnamon > clove > lemongrass > peppermint > pine needle 순으로 항균활성을 나타냈다. Cinnamon과 clove 정유의 최소억제농도(MIC)와 최소살균농도(MBC)는 각각 0.63-1.25 mg/mL과 1.25-2. mg/mL의 범위를 나타냈으며, lemongrass 정유의 MIC와 MBC는 각각 1.25-2.50 mg/mL 과 2.50-5.00 mg/mL로 약간 낮은 항균활성을 나타냈다. 정유 3종의 biofilm 형성 예방효과는 식중독 미생물과 polyethylene 및 stainless steel에 따라 다소 차이가 있었지만, 0.5% 농도의 cinnamon, clove와 lemongrass 정유를 식품접촉 표면에 미리 코팅하였을 때 biofilm 형성에 영향을 주는 것을 확인하였다. 정유의 농도가 증가할수록 모든 식중독 미생물에 대해서 biofilm 형성을 유의적으로 억제하였으며(P<0.05), 0.5% cinnamon과 clove 정유 처리에 의해 L. monocytogenes ATCC 19112와 S. aureus KCCM 11812의 biofilm이 형성되지 않았다. Polyethylene과 stainless steel coupon 표면에 형성된 식중독 미생물의 biofilm의 제거 효과를 측정한 결과, 식중독 미생물의 종류에 따라 차이가 있었지만 정유의 농도가 증가할수록 biofilm 제거 효과는 높아졌으며, 대체로 clove 정유의 biofilm 제거율이 높은 것으로 나타났다. 본 연구를 통하여 0.5%의 cinnamon과 clove 정유는 polyethylene과 stainless steel 표면에 식중독 미생물이 형성하는 biofilm을 예방, 성장 억제 및 제거할 수 있는 천연 소재로 적용이 가능한 것으로 나타났다.
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the colon and rectum with intervals of acute exacerbation. Its etiology remains unknown, although recent studies suggest that pro-inflammatory cytokines initiate the inflammatory responses. In this study, we investigated the ameliorative effects of YB-21 (new product containining Lactobacillus plantarum, Barley Bran and Nymphaeaceae) in a dextran sulfate sodium (DSS)-induced colitis in mice. The experimental groups were divided into 6 groups (n = 10) of ICR mice: normal control(NC), DSS-treated(PC, positive control), DSS+latic-L-treated (3×107CFU/ml), DSS+latic-M-treated (3×109CFU/ml), DSS+latic-H-treated (3×1011CFU/ml), and DSS+YB-21-treated. Histological examinations indicated that YB-21 suppressed edema, mucosal damage, and the loss of crypts induced by DSS. Moreover, YB-21 reduced serum level expressions of, tumor necrosis factor-α (TNF-α). These results suggest that YB-21 has an anti-colitic effect by the suppression of intestinal inflammatory responses in DSS-induced colitis in mice.
본 연구에서는 기존에 인체에 유익한 효과가 있고 부작 용 없이 장기간 안전하게 사용할 수 있으며 간보호 및 간 기능 개선에 탁월한 효과가 있는 표고를 추출 및 농축하여 원유에 농도별로 첨가하여, 3종의 유산균을 이용하여 발효하였다. 표고의 농도를 달리하여 유산균을 배양하였을 때 면역관련 물질인 ergothioneine 및 β-glucan의 함량 을 측정한 결과 ergothioneine함량은 30% 표고추출농축액에 L. plantarum이 첨가되어 배양된 발효물이 40.48 mg/100 g로 가장 높은 함량을 나타냈다. β-Glucan은 30 % 표고추출농축액에 L. brevis가 첨가된 발효물이 13.94 %로 가장 높은 함량이 나타났다. 두 면역관련 물질 모두 표고추출농축액 첨가량이 증가할수록 증가하는 경향을 나타냈다. SD rat을 간을 적출하여 일차 간세포로 분리해 발효물의 간보호 효과를 측정하였다. 표고추출농축액과 유산균 발효물을 10, 50, 100, 500 μg/mL을 일차 간세포에 처리 하여 MTT assay 방법으로 세포독성을 측정한 결과, 모든 농도에서 독성을 보이지 않았다. 또한 10 mM 아세트아미 노펜을 처리하여 독성을 유발한 일차 간세포에 시료를 처리하여 AST, ALT, LDH를 측정한 결과, 효소의 농도가 감소하여 간보호 기능에 효과가 있음을 확인하였다. 이중 L. brevis를 첨가하여 배양한 발효물 처리구에서 효소의 농도가 가장 감소한 것을 보았고, 가장 간보호 효과가 뛰어난 것을 확인하였다. 이상의 결과를 토대로 표고추출농축액에 유산균을 첨가하여 발효하였을 때, 기존의 표고보다 면역관련 물질의 함량이 증가하고, 간기능 보호에 더욱 효과가 있음을 입증하였다. 따라서 본 연구결과는 표고 유산균 발효물이 건강기능 소재로서 연구를 위한 기초 연구자료로 활용될 수 있 것으로 생각된다.
This study was conducted to evaluate the effect of rumen origin lactate-utilizing bacteria (LUB) as one of the potential treatments on subacute ruminal acidosis (SARA) during in vitro challenge compared to buffering agents (NaHCO3, sea minerals, MgO) and direct-fed microorganism (yeast). We hypothesized that rumen LUB (RLUB) could be a potential treatment to treat ruminal acidosis. The supplementation level of other treatments was determined by referring to previous studies in the literature. The 108 CFU/g freeze-dried RLUB isolated from Hanwoo cattle were compared with 0.1% NaHCO3, 0.8% of MgO, 0.5% sea mineral and 0.4% yeast during in vitro SARA challenge. Rumen fluid collected from one cannulated Holstein and one Hanwoo steer fed by maize silage was mixed with 0.5g feed consisted of 0.05g forage and 0.45g concentrate. These mixtures were incubated in triplication for 3, 6, 12 and 24h. After 6h of incubation, along with MgO and sea minerals, RLUB treatment showed higher (p<0.05) ㏗ values than control with no significant differences in total volatile fatty acid concentration. However, in the same period, the propionate concentration and A:P ratio were higher in RLUB than in the other treatment (p<0.05), which might alter the fermentation pattern. On the other hand, the RLUB treatment produced a higher (p<0.05) ammonia-N concentration. Based on these results, we can conclude that RLUB might have the potential to alleviate SARA. Nonetheless, further study on its mechanism in SARA is required, especially with live animals.
In marine ecosystems, the biosynthesis and catabolism of dimethylsulfoniopropionate (DMSP) by marine bacteria is critical to microbial survival and the ocean food chain. Furthermore, these processes also influence sulfur recycling and climate change. Recent studies using emerging genome sequencing data and extensive bioinformatics analysis have enabled us to identify new DMSP-related genes. Currently, seven bacterial DMSP lyases (DddD, DddP, DddY, DddK, DddL, DddQ and DddW), two acrylate degrading enzymes (DddA and DddC), and four demethylases (DmdA, DmdB, DmdC, and DmdD) have been identified and characterized in diverse marine bacteria. In this review, we focus on the biochemical properties of DMSP cleavage enzymes with special attention to DddD, DddA, and DddC pathways. These three enzymes function in the production of acetyl coenzyme A (CoA) and CO2 from DMSP. DddD is a DMSP lyase that converts DMSP to 3-hydroxypropionate with the release of dimethylsulfide. 3-Hydroxypropionate is then converted to malonate semialdehyde by DddA, an alcohol dehydrogenase. Then, DddC transforms malonate semialdehyde to acetyl-CoA and CO2 gas. DddC is a putative methylmalonate semialdehyde dehydrogenase that requires nicotinamide adenine dinucleotide and CoA cofactors. Here we review recent insights into the structural characteristics of these enzymes and the molecular events of DMSP degradation.
본 연구는 증숙밤(95℃, 90분) 페이스트의 발효에 적합한 유산균을 탐색하고 유산균에 의해 발효된 밤 발효 퓨레의 품질적 특성을 조사하였다. 유산균 12종에 대하여 2.0%(v/w)의 농도로 접종하여 3 7℃에서 48시간 발효한 결과 L. plantarum KCTC 21004가 산 생성능이 우수하였다. 증숙밤의 함량, 균 접종량 및 발효온도에 따른 발효 밤 퓨레의 발효 및 품질적 특성을 분석한 결과 물리화학적 특성에는 큰 차이가 나타나지 않았으나 퓨레의 물성 측정시 증숙밤 50% 함량 페이스트가 최적의 조건이었다.