• Journal of Microbiology
• /
• 제45권3호
• /
• pp.205-212
• /
• 2007

Anoxygenic photosynthesis, performed primarily by anoxygenic photosynthetic bacteria (APB), has been supposed to arise on Earth more than 3 billion years ago. The long established APB are distributed in almost every corner where light can reach. However, the relationship between APB phylogeny and source environments has been largely unexplored. Here we retrieved the pufM sequences and related source information of 89 pufM containing species from the public database. Phylogenetic analysis revealed that horizontal gene transfer (HGT) most likely occurred within 11 out of a total 21 pufM subgroups, not only among species within the same class but also among species of different phyla or subphyla. A clear source environment feature related phylogenetic distribution pattern was observed, with all species from oxic habitats and those from anoxic habitats clustering into independent subgroups, respectively. HGT among ancient APB and subsequent long term evolution and adaptation to separated niches may have contributed to the coupling of environment and pufM phylogeny.

• Journal of Species Research
• /
• 제10권4호
• /
• pp.356-363
• /
• 2021

Heterotrophic nanoflagellates (HNFs, 2-20 ㎛ in size) are substantially capable of controlling bacterial abundance in aquatic environments, and microbial taxonomists have studied ecologically important and abundant HNFs for a long time. However, the classifications of HNFs have rarely been reported in Korea on the basis of morphology and 18S rDNA sequencing. Here, previously reported five HNFs from non-Korean habitats were isolated from Korean coastal seawater or intertidal sediments for the first time. Light microscopic observations and 18S rDNA phylogenetic trees revealed that the five isolated species were Cafeteria burkhardae strain PH003, Cafeteria graefeae strain UL001, Aplanochytrium minuta (formerly Labyrinthuloides minuta) strain PH004, Neobodo curvifilus strain KM017 (formerly Procryptobia sorokini), and Ancyromonas micra (formerly Planomonas micra) strain IG005. Being morphologically and phylogenetically indistinct from its closest species, all isolates from Korea were therefore regarded as identical species detected in other countries. Thus, this result indicates an expansion of known habitats that range from those of the five isolates in natural ecosystems on Earth.

• 한국방재안전학회논문집
• /
• 제16권4호
• /
• pp.109-121
• /
• 2023

수제는 하천 내에서 다양한 생태환경을 제공할 수 있어 하천의 환경 기능을 향상시키는 데 활용될 수 있다. 그러나 수제로 인해 변화하는 흐름이 환경 기능을 향상시키는 것만은 아니며, 부정적인 영향을 초래할 수 있다. 따라서 본 연구에서는 수리실험을 통해 수제의 설치로 인한 흐름변화를 분석하여, 어류서식처에 미치는 영향을 검토하였다. 어류의 서식환경의 주요 인자로는 유속, 난류운동에너지 및 재순환영역 등이 있으며, 그 중 난류운동에너지와 재순환영역을 중점적으로 검토하였다. 수제의 간격과 잠김정도를 실험조건으로 설정하여 총 8가지 케이스에서의 실험을 수행하였으며, 실험결과 수제의 간격이 짧고, 잠김정도가 낮을수록 난류운동에너지와 재순환영역의 크기가 증가하여 어류서식처에 미치는 영향이 크게 나타났다.

• 한국수산과학회지
• /
• 제33권6호
• /
• pp.501-507
• /
• 2000

한국산 거머리말속 중 동해 연안에 자생하는 식물의 분포와 생육지 환경의 특성을 파악하기 위해 1998년 6월부터 2000년 7월까지 중부 동해안의 화진포에서부터 남부 동해안 대변까지 조사하였다. 동해 연안에 자생하는 거머리말속은 거머리말, 왕거머리말과 포기거머리말 3종이 조사되었다. 거머리말 생육지는 기수호, 항과만의 수심 $1.3{\~}5.6 m$의 sand와 muddy sand 퇴적 환경에서, 왕거머리말은 수심 $8.5{\~}15.0 m$의 개방된 연안의 sand 퇴적 환경에서 출현하였다. 포기거머리말은 덕산항과 대변항에서 그 생육지가 처음 보고되었으며, 거머리말보다 깊은 지역에서 함께 생육하였다. 거머리말속의 식물 형태는 영양지와 생식지로 구분되었으며, 거머리말 영양지의 길이는 일산의 66.8cm에서부터 감포항의 110.0cm까지, 생식지의 길이는 화진포의 128.0cm에서부터 감포항의 277.8cm까지 생육 지역과 수심에 따라 다양하게 출현하였다. 왕거머리말은 영양지와 생식지가 $64.0{\~}75.7 cm$ 범위로 새로운 표현형으로 생육지의 수심에 영향을 받는 것으로 판단된다. 포기거머리말은 영양지와 생식지가 64.9{\~}70.3 cm$로 생식지가 좀더 길게 성장하였다. 영양염의 농도는 동해 남부 지역이 중부 지역보다 높게 나타났다. 동해안에서 자생하는 거머리말속 식물의 분포는 퇴적 환경보다는 종에 따라 생육 장소(만, 항구와 개방 연안 등)와 수심에 영향을 받고, 수심과 같은 생육 환경의 차이는 식물체의 형태 변이에 영향을 미치는 것으로 조사되었다.

• Journal of Microbiology
• /
• 제45권4호
• /
• pp.281-285
• /
• 2007

Cold environments, including polar and alpine regions, are colonized by a wide diversity of micro-organisms able to thrive at low temperatures. There is evidence of a wide range of metabolic activities in alpine cold ecosystems. Like polar microorganisms, alpine microorganisms playa key ecological role in their natural habitats for nutrient cycling, litter degradation, and many other processes. A number of studies have demonstrated the capacity of alpine microorganisms to degrade efficiently a wide range of hydrocarbons, including phenol, phenol-related compounds and petroleum hydrocarbons, and the feasibility of low-temperature bioremediation of European alpine soils by stimulating the degradation capacity of indigenous microorganisms has also been shown.

• Mycobiology
• /
• 제47권3호
• /
• pp.261-272
• /
• 2019

Oomycetes are widely distributed in various environments, including desert and polar regions. Depending upon different habits and hosts, they have evolved with both saprophytic and pathogenic nutritional modes. Freshwater ecosystem is one of the most important habitats for members of oomycetes. Most studies on oomycete diversity, however, have been biased mostly towards terrestrial phytopathogenic species, rather than aquatic species, although their roles as saprophytes and parasites are essential for freshwater ecosystems. In this study, we isolated oomycete strains from soil sediment, algae, and decaying plant debris in freshwater streams of Korea. The strains were identified based on cultural and morphological characteristics, as well as molecular phylogenetic analyses of ITS rDNA, cox1, and cox2 mtDNA sequences. As a result, we discovered eight oomycete species previously unknown in Korea, namely Phytopythium chamaehyphon, Phytopythium litorale, Phytopythium vexans, Pythium diclinum, Pythium heterothallicum, Pythium inflatum, Pythium intermedium, and Pythium oopapillum. Diversity and ecology of freshwater oomycetes in Korea are poorly understood. This study could contribute to understand their distribution and ecological function in freshwater ecosystem.

• 한국균학회지
• /
• 제49권3호
• /
• pp.351-362
• /
• 2021

Penicillium is the most common fungal genus in various terrestrial and marine environments. The number of new and unrecorded Penicillium species from various substrates and habitats are continuously increasing. As part of a project to discover indigenous fungi in South Korea, three unrecorded Penicillium species were isolated from mudflats and seaweeds. Based on morphological characteristics and phylogenetic analyses of β-tubulin and calmodulin loci, they were identified as P. amaliae, P. infrabuccalum, and P. manginii. Here, we provide a detailed morphological description and sequence information of these previously unrecorded species.

• Mycobiology
• /
• 제50권6호
• /
• pp.420-428
• /
• 2022

Plastic wastes have a negative impact on marine environments; however, they can be used as carbon sources and habitats by certain microbes. Microbes in the marine plastisphere can migrate worldwide through the ocean and cause serious environmental problems when they encounter suitable environments. Therefore, efforts to investigate the microbes inhabiting the marine plastisphere are increasing. In the present study, fungal strains were isolated from plastic wastes buried in Korean sea sands and mudflats and identified using molecular and morphological analyses. Five species were identified that were previously unrecorded from South Korea: Cladosporium funiculosum, Neosetophoma poaceicola, Neosetophoma rosigena, Parasarocladium gamsii, and Trichoderma fomiticola. Their molecular phylogenies and morphological characteristics are described in this study.

• Journal of Microbiology and Biotechnology
• /
• 제31권2호
• /
• pp.240-249
• /
• 2021

Phenotypic plasticity is a rapid response mechanism that enables organisms to acclimate and survive in changing environments. The Chinese mitten crab (Eriocheir sinensis) survives and thrives in different and even introduced habitats, thereby indicating its high phenotypic plasticity. However, the underpinnings of the high plasticity of E. sinensis have not been comprehensively investigated. In this study, we conducted an integrated gut microbiome and muscle metabolome analysis on E. sinensis collected from three different environments, namely, an artificial pond, Yangcheng Lake, and Yangtze River, to uncover the mechanism of its high phenotypic plasticity. Our study presents three divergent gut microbiotas and muscle metabolic profiles that corresponded to the three environments. The composition and diversity of the core gut microbiota (Proteobacteria, Bacteroidetes, Tenericutes, and Firmicutes) varied among the different environments while the metabolites associated with amino acids, fatty acids, and terpene compounds displayed significantly different concentration levels. The results revealed that the gut microbiome community and muscle metabolome were significantly affected by the habitat environments. Our findings indicate the high phenotypic plasticity in terms of gut microbiome and muscle metabolome of E. sinensis when it faces environmental changes, which would also facilitate its acclimation and adaptation to diverse and even introduced environments.

• 한국수산과학회지
• /
• 제56권4호
• /
• pp.462-472
• /
• 2023

We investigated the physio-chemical and geochemical parameters in the spraying shellfish aquacultures (Yeoja and Gangjin Bay) to establish the systematic strategy for effective environmental management. Spatial variation of each parameter showed partially significant difference (P<0.05) between Yeoja and Ganjin Bay, inferring the discriminative progress (i.e., accumulation and degradation) of the autochthonous organic matter within the aquaculture environments. We additionally integrated various properties (e.g., water/sediment quality, natural hazard, and biological health) which may affect the biological growth within the aquaculture habitats based on the biogeochemical cycles related to environmental components and aquaculture species. We used a screening approach (i.e., one out-all out; OOAO) which can permit the assessment of the health levels of aquaculture species, the scoring for other parameters (seawater, sediment, and natural hazard) as three levels (excellent, moderate and poor) depending on the complex interactive properties occurring in the aquaculture environments. Actual, discriminative scores obtained via our case studies may confirm that these stepwise processes are effectively evaluated for optimal health conditions within the aquaculture habitats. Thus, this approach may provide valuable insights for effective environmental management and sustainable growth of aquaculture operation.