• 한국토양비료학회지
• /
• 제47권4호
• /
• pp.254-261
• /
• 2014

The scientific information between microbial activities and chemical properties of reclaimed tidal soil is not enough to apply for reclamation projects. This study was conducted to investigate the relation between chemical properties and microbial activities of reclaimed tidal lands located at western coastal area (25 samples from Nampo, Ewon, Sukmoon and Shihwa sites). Most of the reclaimed soils showed chemical characteristics as salinity soil except Nampo site. The major component influenced the salinity of reclaimed soil was identified as a sodium from the relationship between EC and exchangeable cation. With an increase in EC of soil, the population of mesophilic bacteria decreases whereas halotolerant and halophilic bacteria increases. The population of mesophilic bacteria increased with an increase in both organic matter and dehydrogenase activity. However, the population of halotolerant and halophilic bacteria decreased with an increase in organic matter. Based on the relation between chemical property and microbial activity of reclaimed tidal soil, electrical conductivity and organic matter as chemical properties of soil, population of mesophilic bacteria, halotolerant and halophilic bacteria and dehydrogenase activity as microbial activities could be the major parameters for reclamation process.

• 한국토양비료학회지
• /
• 제49권4호
• /
• pp.381-387
• /
• 2016

The scientific information on the microbial differentiation according to the changes in chemical properties of paddy soil in reclaimed tidal lands is not enough to understand the reclamation processes. The changes in microflora based on the chemical properties of paddy soils at the same sites of reclaimed tidal lands (21 samples from Nampo, Ewon, Sukmoon and Shihwa sites) were investigated in 2013 and 2015. In general, organic matter in paddy soils increased whereas pH decreased with the reclamation time. The electrical conductivities (EC) of soil samples were closely related to the exchangeable $Na^+$. With an increases in EC of paddy soils from 0.39 to $48.9dS\;m^{-1}$, the ratios (%) of halotolerant and halophilic bacteria to mesophilic bacteria proportionally increased from 0.2% to 102,000%. The population of halotolerant and halophilic bacteria in total microflora was also differentiated with the changes in EC of the same sites from reclaimed tidal soils within 2 years. The population of mesophilic bacteria decreased with an increase in EC above $5dS\;m^{-1}$. The microflora including halotolerant and halophilic bacteria could be a candidate as a biological parameter in evaluating the reclamation processes in addition to the chemical index of EC.

• Journal of Microbiology
• /
• 제39권3호
• /
• pp.240-243
• /
• 2001

The effect of cryoprotectants and suspending solutions on the preservation of marine heterotophic bacteria was investigated. Six halotolerant and four halophilic bacterial isolates suspended in either distilled water or artificial seawater were preserved in glycerol and dimethylsulfoxide at -70$\^{C}$, respectively. After one year of preservation, the recovery rates on the appropriate agar plates were estimated. The survival rate was found to be dependent on the strain tested, regardless of the preservation conditions tested.

• 미생물학회지
• /
• 제40권4호
• /
• pp.263-268
• /
• 2004

다섯 종류의 젓갈로부터 다섯 종의 호염성 세균을 분리하였다. 이들의 165-rDNA 염기서열을 분석한 결과 한 종은 Halomonas subglaciescola, 다른 종들은 H. marina에 속하는 것으로 판명되었다. H. subglaciescola, H. marina IN, and H. marina SH-2는 염도가 $3\%$에서 $20\%$에 이르는 넓은 범위의 배양 조건에서, H. marina SQ and H. marina SH-1는 염도가 $8\%$ $19\%$에 이르는 비교적 좁은 범위의 배양 조건에서 성장하는 것으로 나타났다. $15\%$ NaCl을 포함하는 LB 배지에서 배양한 H. subglaciescola, H. marina IN, H. marina SQ, H. marina SH-1, H. marina SH-2의 최대 균체량은 흡광도로서 각각 3.2, 4.5, 4.5, 5.7, 4.2 이었으나 $5\%$의 NaCl을 포함하는 동일 배지에서 최대 균체량은 각각 2.2, 1.1, 0.7, 0.2, 2.4 이었다. 균체의 주사전자현미경 사진에서 균체의 표면에 부정형의 이물질이 부착되 어 있는 것으로 확인되었다. 각 균체의 배양액에서 점성을 갖는 물질을 분리하여 대장균의 배양액에 첨가하였을 때 대장균은 $15\%$ NaCl을 갖는 배지에서 성장하였다. 이것은 호염균의 세포 표면에 부착한 물질이 NaCl의 차단효과를 갖기 때문으로 생각된다.

• 한국토양비료학회지
• /
• 제49권4호
• /
• pp.355-367
• /
• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• 미생물학회지
• /
• 제45권2호
• /
• pp.193-199
• /
• 2009

오징어 젓갈로부터 호염성 균주를 분리하여 형태적, 생리 생화학적 특성 및 분자계통학적 분석을 통하여 동정하였고, 이 균주가 세포외로 생산하는 호염성 protease를 정제하여 그 특성을 분석하였다. 본 균주는 NaCl 0~14%, $20\sim55^{\circ}C$ 및 pH 5~8에서 성장하였으며, $35{\pm}5^{\circ}C$, pH 7 및 5% NaCl에서 최적으로 성장하였다. 주요 지방산 조성은 anteiso-$C_{15:0}$ (44.70%), anteiso-$C_{17:0}$ (15.76%) 및 $C_{16:0}$ (13.91%)이었고, menaquinone은 MK-7이었으며, DNA G+C 함량은 50.58 mol%였다. 16S rRNA 유전자 염기서열을 통한 계통분석 결과 Bacillus이었으며 Bacillus sp. SJ-10으로 명명하였다. SJ-10 균주 배양액으로부터 40% 황산암모늄 침전과 Mono Q 컬럼크로마토그래피 과정을 거쳐 collagen과 gelatin을 특이적으로 분해하는 약 40 kDa의 세포외 protease를 정제하였다. 이 효소는 $35{\pm}5^{\circ}C$, NaCl $5{\pm}1%$ 및 pH 8에서 최적 활성을 나타냈으며, pH 5~10 범위에서 안정하였다.