• 한국환경농학회지
• /
• 제40권1호
• /
• pp.49-59
• /
• 2021

BACKGROUND: Soil salinity causes reduction of crop productivity. Rhizosphere microbes have metabolic capabilities and ability to adaptation of plants to biotic and abiotic stresses. Plant growth-promoting bacteria (PGPB) could play a role as elicitors for inducing tolerance to stresses in plants by affecting resident microorganism in soil. This study was conducted to demonstrate the effect of selected strains on rhizosphere microbial community under salinity stress. METHODS AND RESULTS: The experiments were conducted in tomato plants in pots containing field soil. Bacterial suspension was inoculated into three-week-old tomato plants, one week after inoculation, and -1,000 kPa-balanced salinity stress was imposed. The physiological and biochemical attributes of plant under salt stress were monitored by evaluating pigment, malondialdehyde (MDA), proline, soil pH, electrical conductivity (EC) and ion concentrations. To demonstrate the effect of selected Bacillus strains on rhizosphere microbial community, soil microbial diversity and abundance were evaluated with Illumina MiSeq sequencing, and primer sets of 341F/805R and ITS3/ITS4 were used for bacterial and fungal communities, respectively. As a result, when the bacterial strains were inoculated and then salinity stress was imposed, the inoculation decreases the stress susceptibility including reduction in lipid peroxidation, enhanced pigmentation and proline accumulation which subsequently resulted in better plant growth. However, bacterial inoculations did not affect diversity (observed OTUs, ACE, Chao1 and Shannon) and structure (principle coordinate analysis) of microbial communities under salinity stress. Furthermore, relative abundance in microbial communities had no significant difference between bacterial treated- and untreated-soils under salinity stress. CONCLUSION: Inoculation of Bacillus strains could affect plant responses and soil pH of tomato plants under salinity stress, whereas microbial diversity and abundance had no significant difference by the bacterial treatments. These findings demonstrated that Bacillus strains could alleviate plant's salinity damages by regulating pigments, proline, and MDA contents without significant changes of microbial community in tomato plants, and can be used as effective biostimulators against salinity stress for sustainable agriculture.

• 한국환경보건학회지
• /
• 제47권6호
• /
• pp.540-547
• /
• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• 한국환경보건학회지
• /
• 제48권5호
• /
• pp.282-289
• /
• 2022

Background: Airborne fungi are ubiquitous in the air and exposure to an airborne fungus can be a significant risk factor. The composition of fungi has been potentially important for human health, especially for respiratory diseases like asthma and atopic dermatitis. Therefore, we attempted to ascertain what kind of airborne fungi affect human health at a nationwide level. Objectives: This study was carried out to provide information on indoor fungi distribution at multi-use facilities throughout South Korea. Methods: We classified our data by region and public facility after collection, cultivation, and identification via the sequencing of the ITS (internal transcribed spacer) region. We investigated whether or not the proliferation of HaCaT cells was affected by the identified airborne fungi. Results: In our data, the most isolated airborne fungi by region were Penicillium spp (Seoul, Daegu), Periconia sp (Gyeonggi-do), Iprex sp (Gangwon-do), Phanerochaete sp (Busan), Bjerkandera sp (Gwangju), and Aspergillus sp (Jeju-do). In the public facilities, the most detected fungi were Cladosporium sp (public transport), Penicillium sp (apartment house, retail market, financial institution, karaoke room), Bjerokandera sp (underground parking lot, public toilet, medical institution), Periconia sp (retail store), and Fusarium sp (general restaurant). Next, we selected twenty airborne fungi to examine their cytotoxicity and proliferation of human skin cells. In this experiment, the proliferation of the cells was influenced by most of the identified fungi. In case of the cytotoxicity test, most genera except for Rhodotorula sp and Moesziomyces sp showed cytotoxicity in HaCaT cells. Conclusions: The distribution of mold in the indoor air in multi-use facilities in South Korea differs from region to region, and this is an indicator that should be considered in future health impact studies. In addition, as a result of culturing about 20 types of bacteria dominant in indoor air, it was found that most (90%) inhibit the growth of skin cells, which can be harmful to health. An in-depth study of the health effects of floating fungi is needed.

• Journal of Veterinary Science
• /
• 제24권3호
• /
• pp.44.1-44.17
• /
• 2023

Background: Antibiotic resistance is a significant public health concern around the globe. Antimicrobial peptides exhibit broad-spectrum and efficient antibacterial activity with an added advantage of low drug resistance. The higher water content and 3D network structure of the hydrogels are beneficial for maintaining antimicrobial peptide activity and help to prevent degradation. The antimicrobial peptide released from hydrogels also hasten the local wound healing by promoting epithelial tissue regeneration and granulation tissue formation. Objective: This study aimed at developing sodium alginate based hydrogel loaded with a novel antimicrobial peptide Chol-37(F34-R) and to investigate the characteristics in vitro and in vivo as an alternative antibacterial wound dressing to treat infectious wounds. Methods: Hydrogels were developed and optimized by varying the concentrations of crosslinkers and subjected to various characterization tests like cross-sectional morphology, swelling index, percent water contents, water retention ratio, drug release and antibacterial activity in vitro, and Pseudomonas aeruginosa infected wound mice model in vivo. Results: The results indicated that the hydrogel C proved superior in terms of cross-sectional morphology having uniformly sized interconnected pores, a good swelling index, with the capacity to retain a higher quantity of water. Furthermore, the optimized hydrogel has been found to exert a significant antimicrobial activity against bacteria and was also found to prevent bacterial infiltration into the wound site due to forming an impermeable barrier between the wound bed and external environment. The optimized hydrogel was found to significantly hasten skin regeneration in animal models when compared to other treatments in addition to strong inhibitory effect on the release of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α). Conclusions: Our results suggest that sodium alginate -based hydrogels loaded with Chol-37(F34-R) hold the potential to be used as an alternative to conventional antibiotics in treating infectious skin wounds.

• Journal of Veterinary Science
• /
• 제23권1호
• /
• pp.8.1-8.15
• /
• 2022

Background: Brucella infection induces brucellosis, a zoonotic disease. The intracellular circulation process and virulence of Brucella mainly depend on its type IV secretion system (T4SS) expressing secretory effectors. Secreted protein BspJ is a nucleomodulin of Brucella that invades the host cell nucleus. BspJ mediates host energy synthesis and apoptosis through interaction with proteins. However, the mechanism of BspJ as it affects the intracellular survival of Brucella remains to be clarified. Objectives: To verify the functions of nucleomodulin BspJ in Brucella's intracellular infection cycles. Methods: Constructed Brucella abortus BspJ gene deletion strain (B. abortus ∆BspJ) and complement strain (B. abortus pBspJ) and studied their roles in the proliferation of Brucella both in vivo and in vitro. Results: BspJ gene deletion reduced the survival and intracellular proliferation of Brucella at the replicating Brucella-containing vacuoles (rBCV) stage. Compared with the parent strain, the colonization ability of the bacteria in mice was significantly reduced, causing less inflammatory infiltration and pathological damage. We also found that the knockout of BspJ altered the secretion of cytokines (interleukin [IL]-6, IL-1β, IL-10, tumor necrosis factor-α, interferon-γ) in host cells and in mice to affect the intracellular survival of Brucella. Conclusions: BspJ is extremely important for the circulatory proliferation of Brucella in the host, and it may be involved in a previously unknown mechanism of Brucella's intracellular survival.

• Nutrition Research and Practice
• /
• 제17권4호
• /
• pp.616-630
• /
• 2023

BACKGROUND/OBJECTIVES: Indole-3-propionic acid (IPA) is a tryptophan-derived microbial metabolite that has been associated with protective effects against inflammatory and metabolic diseases. However, there is a lack of knowledge regarding the effects of IPA under physiological conditions and at the intestinal level. MATERIALS/METHODS: Human intestinal epithelial Caco-2 cells were treated for 2, 24, and/or 72 h with IPA or its precursors - indole, tryptophan, and propionate - at 1, 10, 100, 250, or 500 μM to assess cell viability, integrity, differentiation, and proliferation. RESULTS: IPA induced cell proliferation and this effect was associated with a higher expression of extracellular signal-regulated kinase 2 (ERK2) and a lower expression of c-Jun. Although indole and propionate also induced cell proliferation, this involved ERK2 and c-Jun independent mechanisms. On the other hand, both tryptophan and propionate increased cell integrity and reduced the expression of claudin-1, whereas propionate decreased cell differentiation. CONCLUSIONS: In conclusion, these findings suggested that IPA and its precursors distinctly contribute to the proliferation, differentiation, and barrier function properties of human intestinal epithelial cells. Moreover, the pro-proliferative effect of IPA in intestinal epithelial cells was not explained by its precursors and is rather related to its whole chemical structure. Maintaining IPA at physiological levels, e.g., through IPA-producing commensal bacteria, may be important to preserve the integrity of the intestinal barrier and play an integral role in maintaining metabolic homeostasis.

• 한국환경농학회지
• /
• 제41권4호
• /
• pp.335-343
• /
• 2022

BACKGROUND: Antibiotics used in animal husbandry for disease prevention and treatment have resulted in the rapid progression of antibiotic resistant bacteria which can be introduced into the environment through livestock feces/manure, disseminating antibiotic resistant genes (ARGs). In this study, fecal samples were collected from the livestock farms located in Jeju Island to investigate the relationship between microbial communities and ARGs. METHODS AND RESULTS: Illumina MiSeq sequencing was applied to characterize microbial communities within each fecal sample. Using quantitative PCR (qPCR), ten ARGs encoding tetracycline resistance (tetB, tetM), sulfonamide resistance (sul1, sul2), fluoroquinolone resistance (qnrD, qnrS), fluoroquinolone and aminoglycoside resistance (aac(6')-Ib), beta-lactam resistance (bla_TEM, bla_CTX-M), macrolide resistance (ermC), a class 1 integronsintegrase gene (intI1), and a class 2 integrons-integrase gene (intI2) were quantified. The results showed that Firmicutes and Bacteroidetes were dominant in human, cow, horse, and pig groups, while Firmicutes and Actinobacteria were dominant in chicken group. Among ARGs, tetM was detected with the highest number of copies, followed by sul1 and sul2. Most of the genera belonging to Firmicutes showed positive correlations with ARGs and integron genes. There were 97, 34, 31, 25, and 22 genera in chicken, cow, pig, human, and horse respectively which showed positive correlations with ARGs and integron genes. In network analysis, we identified diversity of microbial communities which correlated with ARGs and integron genes. CONCLUSION(S): In this study, antibiotic resistance patterns in human and livestock fecal samples were identified. The abundance of ARGs and integron genes detected in the samples were associated with the amount of antibiotics commonly used for human and livestocks. We found diverse microbial communities associated with antibiotics resistance genes in different hosts, suggesting that antibiotics resistance can disseminate across environments through various routes. Identifying the routes of ARG dissemination in the environment would be the first step to overcome the challenge of antibiotic resistance in the future.

• 대한토목학회논문집
• /
• 제28권1B호
• /
• pp.161-168
• /
• 2008

대규모 연안개발에 따른 매립사업으로 연안역의 갯벌 또는 염습지 등의 연안생태환경공간은 해마다 감소하고 있다. 이에 따라 연안역 자연환경의 완화조치(Mitigation)의 일환으로 인공갯벌 및 염습지 개발의 필요성이 대두되어 활발한 연구가 진행되고 있으나, 인공 연안공간 조성시 복원정도의 정량적 평가에 관한 연구는 미흡한 실정이다. 따라서 본 연구에서는 연안생태환경공간 조성지의 복원정도 평가에 대한 기초적인 연구로서, 준설토 배합비에 따라 구분되는 인공갯벌(Zone. P1) 및 염습지(Zone. P2) 현장시험구를 조성하여 생물-화학적 환경인자인 시험구 내 대형저서동물 군집의 생물다양성과 개체수 및 생체량/식생(갈대)의 정착률/종속영양세균수/이화학적 특성(COD, IL, TN, TP, pH)에 대한 환경성 모니터링을 수행하였다. 이 결과를 바탕으로 각 환경인자들의 복원정도를 나타내는 복원지수를 제안하여 연안생태환경공간 조성에 따른 복원정도를 정량적으로 평가하였다.

• Journal of Veterinary Science
• /
• 제25권2호
• /
• pp.23.1-23.15
• /
• 2024

The widespread use of antimicrobials causes antibiotic resistance in bacteria. The use of butyric acid and its derivatives is an alternative tactic. This review summarizes the literature on the role of butyric acid in the body and provides further prospects for the clinical use of its derivatives and delivery methods to the animal body. Thus far, there is evidence confirming the vital role of butyric acid in the body and the effectiveness of its derivatives when used as animal medicines and growth stimulants. Butyric acid salts stimulate immunomodulatory activity by reducing microbial colonization of the intestine and suppressing inflammation. Extraintestinal effects occur against the background of hemoglobinopathy, hypercholesterolemia, insulin resistance, and cerebral ischemia. Butyric acid derivatives inhibit histone deacetylase. Aberrant histone deacetylase activity is associated with the development of certain types of cancer in humans. Feed additives containing butyric acid salts or tributyrin are used widely in animal husbandry. They improve the functional status of the intestine and accelerate animal growth and development. On the other hand, high concentrations of butyric acid stimulate the apoptosis of epithelial cells and disrupt the intestinal barrier function. This review highlights the biological activity and the mechanism of action of butyric acid, its salts, and esters, revealing their role in the treatment of various animal and human diseases. This paper also discussed the possibility of using butyric acid and its derivatives as surface modifiers of enterosorbents to obtain new drugs with bifunctional action.

• 한국식품위생안전성학회지
• /
• 제27권3호
• /
• pp.277-284
• /
• 2012

본 연구는 시기별로 생산지, 판매지(대형마트, 재래시장)에서 수집한 들깻잎과 상추의 미생물 오염도를 분석하고 시기별 유통 온 습도 조사와 보관온도가 대상 작물에 존재하는 미생물 밀도변화에 미치는 영향을 검정하였다. 2월, 5월, 8월, 11월에 충청남도 금산군 추부면 소재의 들깻잎, 상추 생산농가와 경기도 수원시 소재의 대형마트, 재래시장에서 들깻잎, 상추 시료를 수집하여 총호기성균, 대장균군, B. cereus의 수를 정량적으로 분석하였고, E. coli O157:H7, Salmonella spp., L. monocytogenes, S. aureus를 정성적으로 분석하였다. 동시에 생산지에서 물류센터로 운송되는 유통 온 습도를 측정하였다. 비교적 기온이 높은 5월, 8월에 수집한 엽채류 시료의 미생물 오염도는 2월, 11월보다 상대적으로 높은 것으로 나타났다. 생산지와 판매지의 미생물 오염도는 생산지에 비해 판매지에서 높게 나타나는 경우가 많았으며 대형마트과 재래시장 간에는 오염도 차이에 있어서 일정한 경향을 보이지 않았다. 조사시기에 상관없이 엽채류가 수확되어 포장된 이후부터는 90% 이상의 높은 상대습도를 보이고, 유통온도는 5월, 8월에 각각 평균 18.2, $23.2^{\circ}C$로 $15^{\circ}C$ 이상으로 유지되는 것으로 나타났다. 엽채류 보관온도에 따른 background microflora, E. coli O157:H7, B. cereus의 밀도변화는 대부분 $20^{\circ}C$ 이상의 온도로 보관될 경우 초기밀도에 비해 유의하게 증가하는 것을 보였다. 따라서 본 연구에서 수행한 엽채류의 미생물 오염도 조사는 엽채류의 미생물위해성평가(MRA)의 활용될 수 있으며, 엽채류 유통환경 조사와 보관온도에 따른 미생물 변화 조사는 엽채류의 유통 및 보관 기준을 설정하는데 있어 기초적인 자료로 활용될 수 있을 것이다.