• Korean Journal of Microbiology
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• v.36 no.4
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• pp.285-291
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• 2000

To investigate the variations of physicochemical factors and microbial populations in seven stations at water region of Gangjin bay, nutritive salts, water temperature, transparency, suspended solid, salinity, COD, DO, pH, heterotrophic bacteria, fungi and fecal coliform were analysed four times from February to October, 1999. Total fecal coliform and heterotrophic bacterial population during investigation periods ranged 16.1~166.0 CFU/ml and $5.0{\times}10^3$~$13.1{\times}10^3$CFU/ml, respectively. Stational mean values of these bacterial population showed higher densities at the inlet of fresh water inflow than those of other stations. When the aspects of abiotic and biotic parameters measured were analyzed, ecosystem of Gangjin bay was regulated by factors such as inflow of fresh water, nutrient salts, salinity and variation of water temperature during four seasons.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1153-1160
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• 2019

Objective: The objective of this study was to investigate the effect of bamboo grass (Tiliacora triandra, Diels) pellet (Bamboo-Cass) supplementation on feed intake, nutrient digestibility, rumen microbial population and methane production in Thai native beef cattle. Methods: Four Thai native beef cattle bulls ($190{\pm}2kg$) were randomly allotted to four respective dietary treatments in a $4{\times}4$ Latin square design. Treatments were the varying levels of Bamboo-Cass supplementation at 0, 50, 100, and 150 g/head/d, respectively. Rice straw was fed ad libitum and the concentrate offered at 0.5% of body weight. Results: Under this experiment, the findings revealed that acetate and butyrate production were decreased (p<0.05), propionate increased (p<0.05), whilst ruminal $NH_3-N$ concentration was decreased (p<0.05) by supplementation of Bamboo-Cass at 150 g/head/d. Moreover, rice straw intake, and microbial population were linearly increased (p<0.05), while methane production was decreased (p<0.05). Conclusion: The results from the present study indicate that supplementation of Bamboo-Cass at 150 g/head/d significantly enhanced feed intake, decreased protozoa and increased bacterial population, rumen fermentation efficiency while decreased methane production. Therefore, Bamboo-Cass as a supplement is promising as a rumen enhancer in beef cattle fed on rice straw.

• Journal of Ginseng Research
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• v.48 no.2
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• pp.229-235
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• 2024

Background: Plant health is directly related to the change in native microbial diversity and changes in soil health have been implicated as one of the main cause of root rot. However, scarce information is present regarding allelopathic relationship of Panax notoginseng root exudates and pathogenic fungi Fusarium oxysporum in a continuous cropping system. Methods: We analyzed P. notoginseng root exudate in the planting soil for three successive years to determine phenolic acid concentration using GC-MS and HPLC followed by effect on the microbial community assembly. Antioxidant enzymes were checked in the roots to confirm possible resistance in P. notoginseng. Results: Total 29 allelochemicals in the planting soil extract was found with highest concentration (10.54 %) of p-hydroxybenzoic acid. The HPLC showing a year-by-year decrease in p-hydroxybenzoic acid content in soil of different planting years, and an increase in population of F. oxysporum. Moreover, community analysis displayed negative correlation with 2.22 mmol. L^-1 of p-hydroxybenzoic acid correspond to an 18.1 % population of F. oxysporum. Furthermore, in vitro plate assay indicates that medium dose of p-hydroxybenzoic acid (2.5-5 mmol. L^-1) can stimulate the growth of F. oxysporum colonies and the production of macroconidia, as well as cell wall-degrading enzymes. We found that 2-3 mmol. L^-1 of p-hydroxybenzoic acid significantly increased the population of F. oxysporum. Conclusion: In conclusion, our study suggested that p-hydroxybenzoic acid have negative effect on the root system and modified the rhizosphere microbiome so that the host plant became more susceptible to root rot disease.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.28-35
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• 2014

Due to recent interest of the consumers on safe farm products and the government's political support for eco-friendly agriculture, organic fruit production has been growing continuously. This research was conducted in order to study the effect of cover plants on soil microbial community on cover plants and establish an organic fruit cultivation method through choosing optimal cover plant. As a result of investigating soil microbial population density, the bacterial density in soil showed an increasing trend in June compared to April, and there was a decreasing trend in bacterial density of the soil in August compared to June. The density of actinomycetes in soil increased around 1.6 times in June compared to April when the soil was covered with hairy vetch. The increase of filamentous fungus in crimson clover group was 6.1 times higher in June compared to April and in hairy vetch group, the increase was 4.9 times higher in June compared to April. As a result of analyzing DNA extracted from the soil categorized by different types of cover plants using DGGE method, soil collected from April had higher number of bands detected from different locations according to different types of cover plants. Diversity of the bands from the soil collected from August showed higher range of reduction. As a result of analyzing soil microbial community by different period and the types of cover plants using Pyrosequencing method, microbes were detected in the order of Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, and Firmicutes. Distribution rate of Firmicutes increased in the soil collected in August compared to June and this was shown in all types of cover plants by twice the amount.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1303-1310
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• 2016

Although many studies on the effects of genetically modified (GM) crops on soil microorganisms have been carried out over the past decades, they have provided contradictory information, even for the same GM crop, owing to the diversity of the soil environments in which they were conducted. This inconsistency in results suggests that the effects of GM crops on soil microorganisms should be considered from many aspects. In this study, we investigated the effects of the GM drought-tolerant rice MSRB2-Bar-8, which expresses the CaMSRB2 gene, on soil microorganisms based on the culture-dependent and culture-independent methods. To this end, rhizosphere soils of GM and non-GM (IM) rice were analyzed for soil chemistry, population densities of soil microorganisms, and microbial community structure (using pyrosequencing technology) at three growth stages (seedling, tillering, and maturity). There was no significant difference in the soil chemistry between GM and non-GM rice. The microbial densities of the GM soils were found to be within the range of those of the non-GM rice. In the pyrosequencing analyses, Proteobacteria and Chloroflexi were dominant at the seedling stage, while Chloroflexi showed dominance over Proteobacteria at the maturity stage in both the GM and non-GM soils. An UPGMA dendrogram showed that the soil microbial communities were clustered by growth stage. Taken together, the results from this study suggest that the effects of MSRB2-Bar-8 cultivation on soil microorganisms are not significant.

• The Plant Pathology Journal
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• v.32 no.2
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• pp.136-144
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• 2016

Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.763-768
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• 2012

This study has been performed to measure the prevalence and microbial flora on chicken slaughtering as well as the processing process from the months of October to November. Whole-chicken rinsing technique was used in order to analyze the incidence of microorganisms on chicken carcass at the stage before chilling (after evisceration), after chilling and after cutting. The swab technique was used on processing the processed samples, such as working plates and cutting knives. Brine and cooling water from four cooling tubs were taken from each processing processes and were used as samples. Furthermore, the matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for whole cell fingerprinting in combination with a dedicated bioinformatic software tool was used to identify the isolated microorganisms. Of the tested samples and processes, brine ($4.50{\pm}0.64$ Log CFU/mL) and chicken carcass before chilling ($4.15{\pm}0.46$ Log CFU/mL) showed the highest population of microorganisms; the predominant microbial flora of them were Moellerella wisconsensis (54.84%), a member of the Enterobacteriaceae family, and Escherichia coli (60.36%), respectively. However, the predominant microbial flora of cut carcass was changed to Staphylococcus aureus (27.32%), which is a kind of pathogenic microorganism that can cause a food-borne illness. Therefore, the slaughtering and processing procedure of chicken are needed to be controlled more hygienically.

• Journal of Pharmaceutical Investigation
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• v.3 no.4
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• pp.5-15
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• 1973

An investigation was carried out on a basis of the bacteriological examination with a view to detecting the degree of bacterial contamination for the 77 samples collected from the locally-sold liquid specialties. It's test period was 50 days from July 10 to August 30, 1971. Specially, the survey has put emphasis on the population of general bacteria and the identification of coli-form group, staphylococcus species, streptococcus species, bacillus species, fungi, and yeast species from liquid samples. The results obtained are summarized as follows; (1) For the 77 samples tested, the contamination of general bacteria was found out as minimun 0, i,e., maximum, $12{\times}10^4$ and the total average $45{\times}10^2$ per milliliter. (2) Although streptococcus species could not be detected with the samples, the contamination of the coli-form and staphylococcus species means the strong suggestion of the possibility of pathogenic bacterial contamination. (3) Specially, the products which stay in the neutral pH range and use suspending agents need to care for the microbial contamination in the manufacturing crocess. (4) It is thought necessary to perform the microbiological quality control in the liquid preparations only at least. (5) As the microbial contamination degree in the liquid decreases according to the elapse of time, the microbiological quality control will have to be carried out immediately after the completion of the manufacturing process in order to know the accurate degree. (6) The author thinks that the main reason of the microbial contamination in the liquid is the contamination during the manufacturing process. (7) For the purpose of prevention of the microbial contamination in liquid, therefore, it is more important to make efforts for the rationalization of manufacturing process, the improvement of equipment and environment, the specific training of workers for hygienic knowledges, etc. rather than the use of preservatives for the preparations.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.52-59
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• 2012

BACKGROUND: Cultivation of genetically modified(GM) crops rapidly has increased in the global agricultural area. Among those, herbicide resistant GM crops are reported to have occupied 89.3 million hectares in 2010. However, cultivation of GM crops in the field evoked the concern of the possibility of gene transfer from transgenic plant into soil microorganisms. In our present study, we have assessed the effects of herbicide-resistant GM Chinese cabbage on the surrounding soil microbial community. METHODS AND RESULTS: The effects of a herbicide-resistant genetically modified (GM) Chinese cabbage on the soil microbial community in its field of growth were assessed using a conventional culture technique and also culture-independent molecular methods. Three replicate field plots were planted with a single GM and four non-GM Chinese cabbages (these included a non-GM counterpart). The soils around these plants were compared using colony counting, denaturing gradient gel electrophoresis and a species diversity index assessment during the growing periods. The bacterial, fungal and actinomycetes population densities of the GM Chinese cabbage soils were found to be within the range of those of the non-GM Chinese cabbage soils. The DGGE banding patterns of the GM and non-GM soils were also similar, suggesting that the bacterial community structures were stable within a given month and were unaffected by the presence of a GM plant. The similarities of the bacterial species diversity indices were consistent with this finding. CONCLUSION: These results indicate that soil microbial communities are unaffected by the cultivation of herbicide-resistant GM Chinese cabbage within the experimental time frame.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.2
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• pp.118-126
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• 2002

To evaluate the correlations of microbial populations with soil healthiness and crop production and establish the criteria for microbial population of soil types. We analyzed the microbial community structure of 13 soils which were different in physical and chemical properties and cultivation methods. According to the analysis of microbial population suing the dilution plate method, the large differences of the microbial population structures among soil types were shown: aerobic bacteria $2-27{\times}10^6$, fluorescent Pseudomonas $1-1,364{\times}10^5$, Gram negative bacteria $1-126{\times}10^4$, and mesophilic Bacillus $1-110{\times}10^5$. The density of Gram negative bacteria was highest on red pepper cultivating soils (sample no. 4 and 6) of Umsung and Gesan, Chungbuk, and the density of the fluorescent Pseudomonas was highest on greenhouse soil (sample no. 7) of Jinju, Kyungnam. The crop productivity of three soils was high as compared with those of other soils. It was supposed that the density of fluorescent Pseudomonas and mesophilic Bacillus were correlated with the incresed crop production. By MIDI analysis, 579 strains isolated from 13 soils composed of a variety of microbes including 102 isolates of Agrobacterium, 112 isolates of Bacillus, 32 isolates of Pseudomonas, 44 isolates of Kocuria, and 34 isolates of Pseudomonas. Among the 624 isolates of Gram negative bacteria, Pseudomonas including P. putida and p. fluorescens occupied the highest density (51%), and Stenotrophomonas maltophilia and Burkholderia cepacia also appeared at high density. From RAPD analysis, the fluorescent Pseudomonas strains isolated from 13 soil types showed a high level of strain diversities and were grouped into 2 - 14 patterns according to soil types. Many of unknown bacteria were recovered from the paddy soil, and needed to be further characterized on the molecular basis.