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Microbial Leaching of Iron from Shinyemi Magnetite Ore (미생물을 이용한 신예미 자철광으로부터 철 침출에 관한 연구)

  • Roh, Yul;Oh, Jong-Min;Suh, Yong-Jae;Jang, Hee-Dong
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.4
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    • pp.357-366
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    • 2007
  • Microorganisms participate in a variety of geochemical processes such as weathering and formation of minerals, leaching of precious metals from minerals, and cycling of organic matter The objective of this study was to investigate biogeochemical processes of iron leaching from magnetite ore by iron-reducing bacteria isolated from intertidal flat sediments, southwestern part of Korea. Microbial iron leaching experiments were performed using magnetite ore, Shinyemi magnetite ore, in well-defined media with and without bacteria at room temperature for a month. Water soluble Fe and Mn during the leaching experiments were determined by ICP analysis of bioleached samples, and the resulting precipitated solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of iron leaching from magnetite in the aerobic conditions (Fe = 15 mg/L and Mn = 3.41 mg/L) was lower than that in the anaerobic environments (Fe = 32.8 mg/L and Mn = 5.23 mg/L). The medium pH typically decreased from 8.3 to 7.2 during a month incubation. The Eh of the initial medium decreased from +144.9 mV to -331.7 mV in aerobic environments and from -2.3 mV to -494.6 mV in anaerobic environments upon incubation with the metal reducing microorganisms. The decrease in pH is due to glucose fermentation producing organic acids and $CO_2$. The ability of bacteria to leach soluble iron from crystalline magnetite could have significant implications for biogeochemical processes in sediments where Fe(III) in magnetite represents the largest pool of electron acceptor as well as to use as a novel biotechnology for leaching precious and heavy metals from raw materials.

Macrozoobenthic Community Structures in the Shallow Subtidal Soft-bottoms around Wando-Doam Bay during Summer Season (남해 완도-도암만 연성기질의 여름철 대형저서동물의 군집구조)

  • LIM, HYUN-SIG;CHOI, JIN-WOO;SON, MIN-HO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.23 no.2
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    • pp.91-108
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    • 2018
  • An ecological study on subtidal macrobenthic fauna was conducted from 25 stations in the estuarine area of Wando-Doam Bay, southern coast of Korea during August 2013. A total of 186 species was collected with a mean density of $1,229ind./m^2$ and a mean biomass of $265.7g/m^2$. Polychaetes showed the richest benthic fauna comprising 43% of total fauna, whereas mollusks appeared as density- and biomass-dominant fauna accounted for 45% and 48% of the mean density and biomass, respectively. The number of species and mean faunal density were relatively higher at the stations surrounded by Sinjido, Joyakdo and Gogeumdo showing a gradual decrease toward inner bay stations. Species number and density were negatively correlated with bottom water temperature, but they were positively correlated with both the bottom salinity and DO. The most dominant species in terms of density was a semelid bivalve, Theora fragilis which showed a positive correlation with TOC content of surface sediment and its high density occurred around Gogeum-Sinji-Joyakdo area where dense aquaculture facilities exist. In the bay mouth area, an amphipod species, Eriopisella sechellensis showed its higher density at the stations with low organic content but fine grains. The combination of water temperature, salinity, pH of bottom water, water and sulfur content of the surface sediment could explain 71% of the spatial distribution of macrobenthic fauna from the Bio-Env analysis. From the cluster analysis, the study area consisted of 6 distinct station groups lineated from offshore area toward inner area. Ampharete arctica, Goniada maculata, Eriopisella sechellensis, Theora fragilis, Caprella sp. were identified as the main contributing faunas in classification by the SIMPER analysis. From the value of BPI, the benthic communities at the inner and central Wando-Doam Bay were assessed to be in a normal condition whereas those at the outer Wando harbor and Gogeum-Sinji-Joyakdo area were assessed in a poor or very poor condition due to the high concentration of particulate organic matter might be originated from the nearby dense aquaculture facilities. This study indicated that pristine inner bay has been influenced by the organic material supplied from the outer bay. Thus it is necessary to establish an ecological management plan to reduce organic enrichment of sediment from dense aquaculture facilities in the outer bay.

Analysis of Trans Fatty Acid Content in Processed Foods and Meat Products (가공식품과 육가공품의 트랜스 지방산 함량 조사)

  • Park, Jung-Min;Ji, Won-Gu;Kim, Eun-Jung;Park, Da-Jung;Shin, Jin-Ho;Shim, Soon-Mi;Suh, Hyung-Joo;Chang, Un-Jae;Kang, Duk-Ho;Kim, Jin-Man
    • Food Science of Animal Resources
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    • v.27 no.4
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    • pp.531-537
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    • 2007
  • Small amounts of trans fatty acids exist naturally in beef and dairy foods. Also, they can be produced in the process of partial hydrogenation to manufacture shortning or margarine. They can provide a better palatability and shelf life. According to the recently studies, trans fatty acids can raise health risk such as heart diseases and coronary artery diseases. They can also increase low-density lipoprotein (LDL) cholesterol and decrease high-density lipoprotein (HDL) cholesterol in the blood plasma, therefore increasing the risk of atherosclerosis and diabetes. The aim of this study was to determine total lipids and trans fatty acids (TFAs) content in processed foods and meat products. The analysis of trans fatty acids was performed in 28 samples of donuts, 18 samples of bakeries, 4 samples of frozen doughs, 2 samples of popcorns, and 4 samples of meat products (ham, sausage, nuget, and bacon). Total lipids in processed foods and meat products were extracted by chloroform-Methanol method and acid digestion, respectively. They were analyzed by gas chromatography using a SP-2560 column and flame ionization detector. The amounts of TFAs per 100 g of foods were 0-3.3% (0.74% on average) in donuts, 0.2-5.8% (1.18% on average) in bakeries, 0.2-6.3% (1.93% on average) in frozen doughs, and 0-5.8% in popcorns. Meat products such as ham, sausage, and nuget analyzed 0.1% of TFAs, respectively and trans fatty acids in bacon were not detected. As a result, the distribution of TFAs in processed foods was widely ranged from O% to 6.3% according to manufacturers and types of products, whereas the content of TFAs in meat products ranged from 0% to 0.1%.

Effect of Tomato Powder on Meat Patties as Nitrite Alternatives (미트패티에 아질산 대체제로서의 토마토분말 효과)

  • Kim, Il-Suk;Jin, Sang-Keun;Hur, In-Chul;Choi, Seung-Yun;Jung, Hyun-Jung;Lee, Jung-Keun;Kang, Sang-Ha;Woo, Gyung-Min;Kang, Suk-Nam
    • Food Science of Animal Resources
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    • v.29 no.3
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    • pp.382-390
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    • 2009
  • This study was carried out to determine the effects of tomato powder (TP) as nitrite (NT) on pork patties. The following treatments were made: 0.01% NT (Tl), 0.01% NT and 1.0% TP (T2), 0.5% TP (T3), 1.0% TP (T4), and 0.01% NT and 1.0% TP (T5) were in basal formula (C). The following observations were made: T5 displayed lower gumminess and adhesiveness values than those of C and T1 (p<0.05) on Day 1 of storage; the hardness and surface hardness of T3 and T4 were relatively lower and the surface hardness and gumminess of T3 were relatively higher than the others (p<0.05) on Day 21 of storage; Y4 had significantly lower TBARS values than the others during storage; VBN values of the tested groups were significantly lower than the control samples on Day 7 and 21 of storage; T3 and T4 samples displayed lower pH values (p<0.05) than the control samples on Day 21 of storage; T3, T4 and T5 revealed lower CIE $L^*$ and W than those of C and T1 during storage; T2 had the highest CIE $a^*$ (p<0.05); T4 had significantly higher CIE $b^*$ and chroma values than those of others; T3 and T4 had significantly lower total plate counts than the others; T1 had significantly lower yeast and mold and Staphylococcus sp. counts than the other groups'; and T1 and T2 displayed significantly higher color acceptability than the others.

Changes in Aquatic Insect Community Structure in Wonju Stream based on a Comparison of Previous Studies (과거 문헌 비교를 통한 원주천 수서곤충 군집구조 변화)

  • Han, Jung Soo;Choi, Jun Kil;Won, Kyung Ho;Lee, Hwang Goo
    • Korean Journal of Environmental Biology
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    • v.36 no.3
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    • pp.400-411
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    • 2018
  • This study was a survey of the Wonju stream in Wonju city from May 2015 to September 2016. A total of three sites were selected from the upstream area Gwanseol-dong to the downstream area Hojeo-myeon. Physicochemical analysis, aquatic insect changes, cluster analysis, functional group analysis, rarefaction curve, and statistical analysis were compared between 2004 and 2016. A total of 19 species (38.78%) in 2004 and 22 species (36.67%) in 2016 were analyzed, with the largest number belonging to ephemeroptera. The individual ratio ranged from 27,759.2 (ind. $m^{-2}$, 84.30%) in 2004 to 4,573.2 (ind. $m^{-2}$, 41.64%) in 2016, with the highest number involving diptera. As a result of the community analysis, significant differences were detected in the indices of dominance, diversity, evenness, and richness in 2004 and 2016 (p<0.05). Burrowers of the habitat orientation groups showed the greatest variation with an average of -68.00% (${\pm}2.15$) and the collector-gatherers of the functional feeding groups showed the highest variation of -40.12% (${\pm}1.77$). The rarefaction curve analysis suggested that the species was the poorest in the midstream regions in 2004 and 2016. Physical factors and water quality showed a significant correlation with diversity index, evenness index, and the number of individuals. MDS analysis of the similarity of upstream and downstream regions was high in 2004, and low in 2016. The differences were attributed to physicochemical changes such as increase in flow velocity due to improvement of small dams and changes in bottom structure.

Evaluation of the Anti-oxidant Activity of Pueraria Extract Fermented by Lactobacillus rhamnosus BHN-LAB 76 (Lactobacillus rhamnosus BHN-LAB 76에 의한 Pueraria 발효 추출물의 항산화 활성 평가)

  • Kim, Byung-Hyuk;Jang, Jong-Ok;Lee, Jun-Hyeong;Park, Ye-Eun;Kim, Jung-Gyu;Yoon, Yeo-Cho;Jeong, Su Jin;Kwon, Gi-Seok;Lee, Jung-Bok
    • Journal of Life Science
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    • v.29 no.5
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    • pp.545-554
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    • 2019
  • The phytochemical compounds of Pueraria, a medicinally important leguminous plant, include various isoflavones that have weak estrogenic activity and a potential role in preventing chronic disease, cancer, osteoporosis, and postmenopausal syndrome. However, the major isoflavones are derivatives of puerarin and occur mainly as unabsorbable and biologically inactive glycosides. The bioavailability of the glucosides can be increased by hydrolysis of the sugar moiety using ${\beta}$-glucosidase. In this study, we investigated the antioxidant effects of a Pueraria extract after fermentation by Lactobacillus rhamnosus BHN-LAB 76. The L. rhamnosus BHN-LAB 76 strain was inoculated into Pueraria powder and fermented at $37^{\circ}C$ for 72 hr. The total polyphenol content of the Pueraria extract increased by about 134% and the total flavonoid content increased around 110% after fermentation with L. rhamnosus BHN-LAB 76 when compared to a non-fermented Pueraria extract. Superoxide dismutase-like activities, DPPH radical scavenging, and ABTS radical scavenging increased by approximately 213%, 190%, and 107%, respectively, in the fermented Pueraria extract compared to the non-fermented Pueraria extract. Fermentation of Pueraria extracts with L. rhamnosus BHN-LAB 76 is therefore possible and can effectively increase the antioxidant effects. These results can be applied to the development of improved foods and cosmetic materials.

Increased Anti-oxidative Activity and Whitening Effects of a Saposhnikovia Extract Following Bioconversion Fermentation using Lactobacillus plantarum BHN-LAB 33 (Lactobacillus plantarum BHN-LAB 33의 생물전환공정을 통한 방풍 발효 추출물의 항산화 활성 및 미백 활성 증대 효과)

  • Kim, Byung-Hyuk;Jang, Jong-Ok;Lee, Jun-Hyeong;Park, YeEun;Kim, Jung-Gyu;Yoon, Yeo-Cho;Jeong, Su Jin;Kwon, Gi-Seok;Lee, Jung-Bok
    • Journal of Life Science
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    • v.29 no.11
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    • pp.1208-1217
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    • 2019
  • Saposhnikovia has been used as a traditional medicinal herb in Asia because of the reported anti-inflammatory, anti-allergic rhinitis, pro-whitening, anti-atopy, anti-allergy, and anti-dermatopathy effects of the phytochemical compounds it contains. In this study, we investigated the antioxidant effects of a Saposhnikovia extract after fermentation by Lactobacillus plantarum BHN-LAB 33. Saposhnikovia powder was inoculated with L. plantarum BHN-LAB 33 and fermented at $37^{\circ}C$ for 72 hr. After fermentation, the total polyphenol content of the Saposhnikovia extract increased by about 14%, and the total flavonoid content increased by about 9%. The superoxide dismutase-like activities, DPPH radical scavenging, ABTS radical scavenging, reducing power activity, and tyrosinase inhibition activity also increased after fermentation by approximately 70%, 80%, 45%, 39%, and 44%, respectively. The results confirmed that fermentation of a Saposhnikovia extract by L. plantarum BHN-LAB 33 is an effective way to increase the antioxidant effects of the extract. The bioconversion process investigated in this study may have the potential to produce phytochemical-enriched natural antioxidant agents with high added value from Saposhnikovia matrices. These results can also be applied to the development of improved foods and cosmetic materials.

Distribution Characteristics, Population Structure and Dynamics of the Endangered Plant, Viola websteri Hemsl. (멸종위기야생식물인 왕제비꽃(Viola websteri Hemsl.)의 분포특성과 개체군 구조 및 동태)

  • Chae, Hyun-Hee;Kim, Young-Chul;Kwak, Myoung-Hai;Nam, Gi-Heum
    • Korean Journal of Environment and Ecology
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    • v.35 no.1
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    • pp.48-67
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    • 2021
  • Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

Difference of perception of the duties of dental hygienist between dentists and dental hygiene students in an area (일개 지역 치과의사와 치위생학과 학생 간 치과위생사의 업무에 대한 인식의 차이)

  • Hwang, Soo-Jeong;Koong, Hwa-Soo;Lee, Sang-Hoon
    • Journal of Korean Academy of Dental Administration
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    • v.5 no.1
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    • pp.1-12
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    • 2017
  • Although dental hygienists have performed chair-side assisting and other dental cares as well as preventive dental cares in Korea, medical technician law confines duties of dental hygienists as closed narrative. The aim of this study was to investigate difference in perception of duties of dental hygienists in dental clinic between dentists and dental hygiene students. A total of 245 copies of questionnaires were distributed to dentists and students by post-mail. Only 42 dentists and 30 students in an area replied these questionnaires about the present and future duties of dental hygienists after providing written consent. Both groups agreed that intra and extra oral X-ray taking, education about oral health behavior, instruction after dental treatment, chair-side assisting, consulting for patients, scaling, initial impression taking, management of dental materials and equipment, sterilization of equipment, and receiving dental bills are duties of dental hygienists. However, they had different perceptions about various dental treatments as duties of dental hygienists even if they were under instructions of a dentist, including infiltration anesthesia, filling in cavity, intramuscular injection, FC change, canal irrigation, orthodontic treatment including separating, ligature bracket bonding and removing, setting crown and bridge, making individual, removing implant screw, and so on. These findings demonstrated that there were different perceptions about duties of dental hygienists between dentists and dental hygiene students, especially on dental treatment.

Brief Introduction of Research Progresses in Control and Biocontrol of Clubroot Disease in China

  • He, Yueqiu;Wu, Yixin;He, Pengfei;Li, Xinyu
    • 한국균학회소식:학술대회논문집
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    • 2015.05a
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    • pp.45-46
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    • 2015
  • Clubroot disease of crucifers has occurred since 1957. It has spread to the whole China, especially in the southwest and nourtheast where it causes 30-80% loss in some fields. The disease has being expanded in the recent years as seeds are imported and the floating seedling system practices. For its effective control, the Ministry of Agriculture of China set up a program in 2010 and a research team led by Dr. Yueqiu HE, Yunnan Agricultural University. The team includes 20 main reseachers of 11 universities and 5 institutions. After 5 years, the team has made a lot of progresses in disease occurrence regulation, resources collection, resistance identification and breeding, biological agent exploration, formulation, chemicals evaluation, and control strategy. About 1200 collections of local and commercial crucifers were identified in the field and by artificiall inoculation in the laboratories, 10 resistant cultivars were breeded including 7 Chinese cabbages and 3 cabbages. More than 800 antagostic strains were isolated including bacteria, stretomyces and fungi. Around 100 chemicals were evaluated in the field and greenhouse based on its control effect, among them, 6 showed high control effect, especially fluazinam and cyazofamid could control about 80% the disease. However, fluzinam has negative effect on soil microbes. Clubroot disease could not be controlled by bioagents and chemicals once when the pathogen Plasmodiophora brassicae infected its hosts and set up the parasitic relationship. We found the earlier the pathogent infected its host, the severer the disease was. Therefore, early control was the most effective. For Chinese cabbage, all controlling measures should be taken in the early 30 days because the new infection could not cause severe symptom after 30 days of seeding. For example, a biocontrol agent, Bacillus subtilis Strain XF-1 could control the disease 70%-85% averagely when it mixed with seedling substrate and was drenching 3 times after transplanting, i.e. immediately, 7 days, 14 days. XF-1 has been deeply researched in control mechanisms, its genome, and development and application of biocontrol formulate. It could produce antagonistic protein, enzyme, antibiotics and IAA, which promoted rhizogenesis and growth. Its The genome was sequenced by Illumina/Solexa Genome Analyzer to assembled into 20 scaffolds then the gaps between scaffolds were filled by long fragment PCR amplification to obtain complet genmone with 4,061,186 bp in size. The whole genome was found to have 43.8% GC, 108 tandem repeats with an average of 2.65 copies and 84 transposons. The CDSs were predicted as 3,853 in which 112 CDSs were predicted to secondary metabolite biosynthesis, transport and catabolism. Among those, five NRPS/PKS giant gene clusters being responsible for the biosynthesis of polyketide (pksABCDEFHJLMNRS in size 72.9 kb), surfactin(srfABCD, 26.148 kb, bacilysin(bacABCDE 5.903 kb), bacillibactin(dhbABCEF, 11.774 kb) and fengycin(ppsABCDE, 37.799 kb) have high homolgous to fuction confirmed biosynthesis gene in other strain. Moreover, there are many of key regulatory genes for secondary metabolites from XF-1, such as comABPQKX Z, degQ, sfp, yczE, degU, ycxABCD and ywfG. were also predicted. Therefore, XF-1 has potential of biosynthesis for secondary metabolites surfactin, fengycin, bacillibactin, bacilysin and Bacillaene. Thirty two compounds were detected from cell extracts of XF-1 by MALDI-TOF-MS, including one Macrolactin (m/z 441.06), two fusaricidin (m/z 850.493 and 968.515), one circulocin (m/z 852.509), nine surfactin (m/z 1044.656~1102.652), five iturin (m/z 1096.631~1150.57) and forty fengycin (m/z 1449.79~1543.805). The top three compositions types (contening 56.67% of total extract) are surfactin, iturin and fengycin, in which the most abundant is the surfactin type composition 30.37% of total extract and in second place is the fengycin with 23.28% content with rich diversity of chemical structure, and the smallest one is the iturin with 3.02% content. Moreover, the same main compositions were detected in Bacillus sp.355 which is also a good effects biocontol bacterial for controlling the clubroot of crucifer. Wherefore those compounds surfactin, iturin and fengycin maybe the main active compositions of XF-1 against P. brassicae. Twenty one fengycin type compounds were evaluate by LC-ESI-MS/MS with antifungal activities, including fengycin A $C_{16{\sim}C19}$, fengycin B $C_{14{\sim}C17}$, fengycin C $C_{15{\sim}C18}$, fengycin D $C_{15{\sim}C18}$ and fengycin S $C_{15{\sim}C18}$. Furthermore, one novel compound was identified as Dehydroxyfengycin $C_{17}$ according its MS, 1D and 2D NMR spectral data, which molecular weight is 1488.8480 Da and formula $C_{75}H_{116}N_{12}O_{19}$. The fengycin type compounds (FTCPs $250{\mu}g/mL$) were used to treat the resting spores of P. brassicae ($10^7/mL$) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A260) and at 280 nm (A280) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be lyzed by the FTCPs of XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol. In the five selected medium MOLP, PSA, LB, Landy and LD, the most suitable for growth of strain medium is MOLP, and the least for strains longevity is the Landy sucrose medium. However, the lipopeptide highest yield is in Landy sucrose medium. The lipopeptides in five medium were analyzed with HPLC, and the results showed that lipopeptides component were same, while their contents from B. subtilis XF-1 fermented in five medium were different. We found that it is the lipopeptides content but ingredients of XF-1 could be impacted by medium and lacking of nutrition seems promoting lipopeptides secretion from XF-1. The volatile components with inhibition fungal Cylindrocarpon spp. activity which were collect in sealed vesel were detected with metheds of HS-SPME-GC-MS in eight biocontrol Bacillus species and four positive mutant strains of XF-1 mutagenized with chemical mutagens, respectively. They have same main volatile components including pyrazine, aldehydes, oxazolidinone and sulfide which are composed of 91.62% in XF-1, in which, the most abundant is the pyrazine type composition with 47.03%, and in second place is the aldehydes with 23.84%, and the third place is oxazolidinone with 15.68%, and the smallest ones is the sulfide with 5.07%.

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