• 한국토양비료학회지
• /
• 제47권6호
• /
• pp.451-456
• /
• 2014

Organic amendment practices can influence diversity and activities of soil microorganisms. There is a need to investigate this impact compared with other types of materials. This study was carried out to evaluate the long term effects of chemical and organic fertilizer on soil microbial community in upland field. During the last 11 years green manure, rice straw compost, rapeseed cake, pig mature compost, NPK, and NPK + pig mature compost were treated in upland soil. Organic fertilizer treatment found with high bacterial colony forming units (CFUs) as compared to chemical and without fertilizer treatment. There was no significant difference in the actinomycetes and fungal population. The average well color development (AWCD) value was the highest in green manure and, the lowest in without fertilizer treatment. Analyses based on the denaturing gradient gel electrophoresis (DGGE) profile showed that rice straw compost and pig mature compost had a similar banding pattern while rapeseed cake, NPK, NPK + pig mature compost and without fertilizer treatment were clustered in another cluster and clearly distinguished from green manure treatment. Bacterial diversity can be highly increased by the application of organic fertilizer while chemical fertilizer had less impact. It can be concluded that green manure had a beneficial impact on soil microbial flora, while, the use of chemical fertilizer could affect the soil bacterial communities adversely.

• Journal of Microbiology and Biotechnology
• /
• 제28권9호
• /
• pp.1517-1526
• /
• 2018

Investigating bacterial diversity and its metabolic capabilities is crucial for interpreting the ecological patterns in a desert environment and assessing the presence of exploitable microbial resources. In this study, we evaluated the spatial heterogeneity of physicochemical parameters, soil bacterial diversity and metabolic adaptation at meter scale. Soil samples were collected from two quadrats of a desert (Thar Desert, India) with a hot, arid climate, very little rainfall and extreme temperatures. Analysis of physico-chemical parameters and subsequent variance analysis (p-values < 0.05) revealed that sulfate, potassium and magnesium ions were the most variable between the quadrats. Microbial diversity of the two quadrats was studied using Illumina bar-coded sequencing by targeting V3-V4 regions of 16S rDNA. As for the results, 702504 high-quality sequence reads, assigned to 173 operational taxonomic units (OTUs) at species level, were examined. The most abundant phyla in both quadrats were Actinobacteria (38.72%), Proteobacteria (32.94%), and Acidobacteria (9.24%). At genus level, Gaiella represented highest prevalence, followed by Streptomyces, Solirubrobacter, Aciditerrimonas, Geminicoccus, Geodermatophilus, Microvirga, and Rubrobacter. Between the quadrats, significant difference (p-values < 0.05) was found in the abundance of Aciditerrimonas, Geodermatophilus, Geminicoccus, Ilumatobacter, Marmoricola, Nakamurella, and Solirubrobacter. Metabolic functional mapping revealed diverse biological activities, and was significantly correlated with physicochemical parameters. The results revealed spatial variation of ions, microbial abundance and functional attributes in the studied quadrats, and patchy nature in local scale. Interestingly, abundance of the biotechnologically important phylum Actinobacteria, with large proposition of unclassified species in the desert, suggested that this arid environment is a promising site for bioprospection.

• Ocean and Polar Research
• /
• 제26권1호
• /
• pp.51-58
• /
• 2004

We isolated and identified culturable Arctic bacteria that had inhabited soils around the Korean Arctic Research Station Dasan located at Ny-Alsund, Svalbard, Norway $(79^{\circ}N,\;12^{\circ}E)$. The collected soils were diluted in distilled water; the diluted soil-water was spread on 3M petri-films at Dasan Station. The petri-films were transported to the laboratory at KORDI, and cultured at $4^{\circ}C$. Colonies grown on the petri-films were subsequently cultured on nutrient agar plates at $4^{\circ}C$ every 7 days. The pure colonies were inoculated into nutrient liquid media, genomic DNA was extracted, and phylogenetic analysis was performed on the basis of 165 rDNA sequences. A total of 227 strains of bacteria were isolated. Among them, 16S rDNA sequences of 185 strains were identical with those of known strains isolated in this study, and 42 strains were finally identified. Phylogenetic analysis using 16S rDNA indicated that the 30 strains belonged to Pseudomonas, 7 strains to Arthrobacter, two strains to Flavobacterium, and the remaining to Achromobacter, Pedobacter, and Psychrobacter. Among the 42 strains, 14 bacteria produced protease: they were 6 strains of Pseudomonax, 4 strains of Arthrobater, an Achromobacter strain, 2 strains of Flavobacterium, and a Pedohacter strain. We expect these Arctic bacteria can be used for screening to develop new industrial enzymes that are active at low temperatures.

• Journal of Veterinary Science
• /
• 제22권3호
• /
• pp.37.1-37.14
• /
• 2021

Background: Ticks are one of the most common external parasites in dogs, and are associated with the transmission of a number of major zoonoses, which result in serious harm to human health and even death. Also, the increasing number of pet dogs and pet owners in China has caused concern regarding human tick-borne illnesses. Accordingly, studies are needed to gain a complete understanding of the bacterial composition and diversity of the ticks that parasitize dogs. Objectives: To date, there have been relatively few reports on the analysis of the bacterial community structure and diversity in ticks that parasitize dogs. The objective of this study was to investigate the microbial composition and diversity of parasitic ticks of dogs, and assessed the effect of tick sex and geographical region on the bacterial composition in two tick genera collected from dogs in China. Methods: A total of 178 whole ticks were subjected to a 16S ribosomal RNA (rRNA) next generation sequencing analysis. The Illumina MiSeq platform targeting the V3-V4 region of the 16S rRNA gene was used to characterize the bacterial communities of the collected ticks. Sequence analysis and taxonomic assignment were performed using QIIME 2 and the GreenGene database, respectively. After clustering the sequences into taxonomic units, the sequences were quality-filtered and rarefied. Results: After pooling 24 tick samples, we identified a total of 2,081 operational taxonomic units, which were assigned to 23 phyla and 328 genera, revealing a diverse bacterial community profile. The high, moderate and low prevalent taxa include 46, 101, and 182 genera, respectively. Among them, dominant taxa include environmental bacterial genera, such as Psychrobacter and Burkholderia. Additionally, some known tick-associated endosymbionts were also detected, including Coxiella, Rickettsia, and Ricketssiella. Also, the potentially pathogenic genera Staphylococcus and Pseudomonas were detected in the tick pools. Moreover, our preliminary study found that the differences in microbial communities are more dependent on the sampling location than tick sex in the tick specimens collected from dogs. Conclusions: The findings of this study support the need for future research on the microbial population present in ticks collected from dogs in China.

• Journal of Microbiology and Biotechnology
• /
• 제12권3호
• /
• pp.382-388
• /
• 2002

In order to assess the effects of organic fertilizer on soil microbial community structure and diversity in the greenhouse fields, fatty acid methyl ester (FAME) was analyzed by the MIDI (Microbial ID, Inc., Newark, DE, U.S.A.) system and enumerations were performed. In relation to bacterial division of each sample, low GC Gram-positive bacteria were predominant among bacteria cultured on aerobic bacteria media. On the other hand, alpha subdivision was predominant on proteobacteria of control and OM (organic matter) 1 treated plot, and Flavobacterium spp. existed in OM2 plot on crystal violet media of all samples. Shannon-weaver Index (H) of OM1 plot varied most by 1.9 and 5.0 among bacteria cultured on aerobic bacteria media and crystal violet media, respectively. Our results revealed that addition of the organic wastes to soil led to a highly diverse microbial community, but the excessive amounts of organic and mineral fertilizer applied in the greenhouse fields produced excess nutrients in soil and led to simplification on bacterial populations.

• The Plant Pathology Journal
• /
• 제34권2호
• /
• pp.143-149
• /
• 2018

Flowers of kiwifruit are morphologically hermaphroditic and survivable binucleate pollen is produced by the male flowers. In this study, we investigated microbial diversity in kiwifruit pollens by analyzing amplicon sequences of 16S rRNA. Four pollen samples were collected: 'NZ' was imported from New Zealand, 'CN' from China in year of 2014, respectively. 'KR13' and 'KR14' were collected in 2013' and 2014' in South Korea. Most of the identified bacterial phyla in the four different pollens were Proteobacteria, Actinobacteria and Firmicutes. However, the imported and the domestic pollen samples showed different aspects of microbial community structures. The domestic pollens had more diverse in diversity than the imported samples. Among top 20 OTUs, Pseudomonas spp. was the most dominant specie. Interestingly, a bacterial pathogen of kiwifruit canker, Pseudomonas syringae pv. actinidiae was detected in 'NZ' by the specific PCR. This study provides insights microbial distribution and community structure information in kiwifruit pollen.

• 한국토양비료학회지
• /
• 제43권6호
• /
• pp.995-1001
• /
• 2010

농경지 토양미생물상의 생물지리학적으로 특성을 보고자 우리나라 농경지 토양 미생물의 다양성을 지도화 하였다. 1999년부터 2007년까지 조사되어 농업환경변동조사로 구축된 미생물 균수 및 미생물체량 자료를 DB화하여 세균, 사상균, 바실러스, 그람음성균 및 미생물체량을 분포도 작성에 이용하였다. 세균, 사상균, 바실러스 및 그람음성균의 분포상은 농경지별로 상이한 경향을 보였다. 토양에 서식하는 미생물의 생체중인 미생물체량은 바실러스와 사상균 수처럼 증가하는 경향을 보였다.

• 한국기후변화학회지
• /
• 제5권3호
• /
• pp.249-256
• /
• 2014

Permafrost is frozen soil below $0^{\circ}C$ for two or more years. Surface of permafrost is called as active layer that seasonally thaws during the summer. Although the thawing of permafrost may deepen the active layer and consequently increase the microbial activity, the microbial community structure in this habitat has not yet been well described. In this study, we presented bacterial and archaeal diversity in the active layer soil from Resolute, Canada using pyrosequencing analysis. The soil sample was collected from the surface of the marsh covered with moss and Carex. A total of 7,796 bacterial reads for 40 phyla and 245 archaeal reads for 4 phyla were collected, reflecting the high diversity of bacteria. Predominant bacterial groups were Proteobacteria (37.7%) and Bacteroidetes (30.0%) in this study. Major groups in Archaea were Euryarchaeota (51.4%) and Thaumarchaeota (46.1%). Both methane producing archaea and consuming bacteria were detected in this study. Although it might be difficult to characterize microbial community with only one sample, it could be used for the basis of assessing the relative importance of the specific groups with a high resolution on the bacterial and archaeal community in this habitat.

• 대한환경공학회지
• /
• 제32권4호
• /
• pp.369-378
• /
• 2010

폐기물매립장의 안정화에는 미생물이 중요한 역할을 수행한다. 폐기물매립장에서 미생물군집 변화 모니터링에 말단 제한절편다형성(Terminal Restriction Fragment Length Polymorphism; T-RFLP)법의 활용 가능성을 평가하고자 박테리아의 16S rDNA 서열에 기초한 T-RFLP법으로 4개의 폐기물매립장 내부에서 채취한 침출수의 미생물군집 구조를 조사하였다. T-RFLP법을 사용하여 해석한 침출수 내 우점 미생물군집 구조와 일반적으로 널리 사용되고 있는 16S rDNA 클론 해석법에 의한 우점 미생물군집구조는 유사하였다. 또한, T-RFLP법을 이용하여 폐기물매립장의 구조, 매립 폐기물 종류, 운영기간이 다른 폐기물매립장 침출수의 우점 미생물군집 구조가 서로 다르게 나타나는 것을 확인 할 수 있었다. 따라서 T-RFLP법을 사용하여 폐기물매립장 침출수내 미생물군집 구조를 장기적으로 모니터링 한다면 많은 비용과 시간이 소요되는 클론해석법의 반복적인 수행 없이도 비교적 간단하게 폐기물매립장의 안정화 정도를 평가할 수 있을 것으로 기대한다.

• Mycobiology
• /
• 제40권2호
• /
• pp.138-141
• /
• 2012

We measured physiological functionalities, including antihypertensive angiotensin I-converting enzyme inhibitory activity and immun-stimulating ${\beta}$-glucan content for sixty kinds of Makgeolli that is commercially available from the market. As a result, we selected R-12 commercial raw Makgeolli, with a high content of immuno-stimulating ${\beta}$-glucan, and R-14 commercial raw Makgeolli, exhibiting high antihypertensive activity. Due to the similarities in their overall physicochemical properties and raw materials used for fermentation, we compared the microbial flora in order to investigate the reason for the differences in their functionalities. Nested PCR and denaturing gradient gel electrophoresis for yeasts and bacteria were performed for analysis of microbial diversity of two different kinds of Makgeolli (i.e., R-12, R-14), which showed immuno-stimulating ${\beta}$-glucan content and exhibited a very high level of antihypertensive activity, respectively. Analysis of the 18S rDNA amplicon revealed a major presence of the yeast strain Pichia burtonii in every Makgeolli sample. Analysis of the 16S rDNA amplicon revealed a predominance of lactic acid bacteria, and the most frequent lactic acid bacteria were Lactobacillus ingluviei, L. fermentum, and L. harbinensis, and Lactobacillus sp. Among these, L. harbinensis was detected only in R-12 and L. ingluviei was found only in R-14. Different functionalities from the individual commercially available Makgeolli may be attributed to actions of different microbial flora during fermentation.