• Applied Biological Chemistry
• /
• v.40 no.2
• /
• pp.167-171
• /
• 1997

Methanol extracts from 25 seed samples belonging to the family Leguminosae were subjected to an in vitro screening for their growth-promoting and inhibitory activities towards Bifidobacterium adolescentis, B. longum, B. bifidum, and Lactobacillus casei, using spectrophotometric and paper disc agar diffusion methods under $O_2-free$ conditions, respectively. The responses varied with both bacterial strains and plant species. Among seed extracts, extracts from Glycine max (light-green color) and Arachis hypogaea (dark-brown) enhanced the growth of lactic acid bacteria in media with or without carbon sources, suggesting that bifidus factor(s) might be involved in the phenomenon. This growth-promoting effect was most pronounced with L. casei among lactic acid bacteria used. Additionally, all seed extracts did not adversely affect the growth of the lactic acid bacteria tested.

• Korean Journal of Environmental Agriculture
• /
• v.20 no.1
• /
• pp.57-62
• /
• 2001

Twelve antagonistic strains against Fusarium wilt of watermelon-rootstock gourd were selected from 54 bacterial isolates which were isolated from the rhizosphere of crop plants growing in various locations. They showed strong inhibitory effects on growth of Fusarium osysporum f. sp. niveum, the causal agent of watermelon-rootstock gourd Fusarium wilt. Among these antagonists, the isolate YJ-3 was the most pronounced in growth-promoting ability for watermelon-rootstock gourd. The growth of watermelon-rootstock gourd in bed soil inoculated with YJ-3 was better by 46 and 13% than those in commercial bed soil alone and in bed soil inoculated with commercial microbial inoculant, respectively. The antagonistic plant growth-promoting rhizobacterium, strain No. YJ-3, was identified as Bacillus sp. on MIDI system. Furthermore, Bacillus sp. YJ-3 showed antifungal activity on growth against Alternaria cucumerina, Botrytis cinerea, Colletotrichum orbiculare, Didymella bryoniae, Rhizoctonia solani and Fusarium oxysporum.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.2
• /
• pp.280-286
• /
• 2007

We evaluated a commercial biopreparation of plant growth-promoting rhizobacteria (PGPR) strains Bacillus subtilis GB03 and B. amyloliquefaciens IN937a formulated with the carrier chitosan (Bio Yield) for its capacity to elicit growth promotion and induced systemic resistance against infection by Cucumber Mosaic Virus (CMV) and Pseudomonas syringae pv. tomato DC3000 in Arabidopsis thaliana. The biopreparation promoted plant growth of Arabidopsis hormonal mutants, which included auxin, gibberellic acid, ethylene, jasmonate, salicylic acid, and brassinosteroid insensitive lines as well as each wild-type. The biopreparation protected plants against CMV based on disease severity in wild-type plants. However, virus titre was not lower in control plants and those treated with biopreparation, suggesting that the biopreparation induced tolerance rather than resistance against CMV. Interestingly, the biopreparation induced resistance against CMV in NahG plants, as evidenced by both reduced disease severity and virus titer. The biopreparation also elicited induced resistance against P. syringae pv. tomato in the wild-type but not in NahG transgenic plants, which degrade endogenous salicylic acid, indicating the involvement of salicylic acid signaling. Our results indicate that some PGPR strains can elicit plant growth promotion by mechanisms that are different from known hormonal signaling pathways. In addition, the mechanism for elicitation of induced resistance by PGPR may be pathogen-dependent. Collectively, the two-Bacilli strain mixture can be utilized as a biological inoculant for both protection of plant against bacterial and viral pathogens and enhancement of plant growth.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 1994.06a
• /
• pp.27-49
• /
• 1994

Root colonization of biocontrol agents via seed treatment was investigated and a compatible combination, Gliocladium virens G872B and Pseudomonas putida Pf3, in colonizing cucumber rhizosphere was confirmed through the study. Much higher number of fungal and bacterial propagules were detected when two isolates were inoculated together. The presence of Pf3 in root system was greatly helpful to G872B to colonize at root tip. The mechanism of this phenomenon is partially elucidated through the results of in vitro experiments and the observations of scanning electron and fluorescence microscope. Addition of Pf3 cells resulted earlier germination of G872B conidia and increased mycelial growth. And the more number of germinated conidia on seed coat, the more vigorous hypal streching and sporulation on the root surface were observed in coinoculated treatment. The propagules of G872B on the cucumber root when they were challenged against the pathogenic Fusarium oxysporum, were even higher than that of G872B treated alone, and the magnitude of such a difference was getting grater toward the root ip and the population of F. oxysporum on the root was reduced by seed inoculation of G872B. The rhizosphere competence was obviously reflected to disease suppression and plant growth promotion that induced by the given isolate. Green house experiments revealed that the combined treatment provided long-term disease suppression with greater rate and the larger amount of fruit yield than single treatments. Through this study the low temperature growing Pseudomonas fluorescens M45 and MC07 were evaluated to apply them to the winter crops in field or plastic film house. In vitro tests reveal that M45 and MC07 inhibited the mycelial growth of Pythium ultimum, Rhizoctona solani and Phytophthora capsici and enhanced growth of cucumber cotyledon in MS agar. This effect was more pronounced when the bacteria were incubated at 14$^{\circ}C$ than at 27$^{\circ}C$. And disease suppression and plant growth promotion in green house were also superior at low temperature condition. Seed treatment of M45 or soil treatment of MC07 brought successful control of damping-off and enhanced seedling growth of cucumber. The combined treatment of two isolates was more effective than any single treatment.

• Food Science of Animal Resources
• /
• v.29 no.3
• /
• pp.289-295
• /
• 2009

The aim of this research was to develop predictive models for the growth of spoilage bacteria (total viable cells, Pseudomonas spp., and lactic acid bacteria) on frankfurters and to estimate the shelf-life of frankfurters under aerobic conditions at various storage temperatures (5, 15, and $25^{\circ}C$). The primary models were determined using the Baranyi model equation. The secondary models for maximum specific growth rate and lag time as functions of temperature were developed by the polynomial model equation. During 21 d of storage under various temperature conditions, lactic acid bacteria showed the longest lag time and the slowest growth rate among spoilage bacteria. The growth patterns of total viable cells and Pseudomonas spp. were similar each other. These data suggest that Pseudomonas spp. might be the dominant spoilage bacteria on frankfurters. As storage temperature increased, the growth rate of spoilage bacteria also increased and the lag time decreased. Furthermore, the shelf-life of frankfurters decreased from 7.0 to 4.3 and 1.9 (d) under increased temperature conditions. These results indicate that the most significant factor for spoilage bacteria growth is storage temperature. The values of $B_f$, $A_f$, RMSE, and $R^2$ indicate that these models were reliable for identifying the point of microbiological hazard for spoilage bacteria in frankfurters.

• Restorative Dentistry and Endodontics
• /
• v.23 no.1
• /
• pp.175-182
• /
• 1998

Polyphosphate has been used to prevent decomposition of foods and has been shown to have inhibitory effect on the growth of gram positive bacteria. The purpose of this study was to evaluate the effect of polyphosphate on the growth of Porphyromonas endodontalis, a gram negative endodontopathic bacterium. Porphyromonas endodontalis ATCC 35406 was grown in the presence of polyphosphates with different chain lengths. Inhibitory effect of each polyphosphate which was added at the beginning or during the culture, was determined by measuring the optical density of the bacterial cell at 540nm and by viable cell count. The results from this study were as follows : 1. Polyphosphates were shown the growth inhibition of the Porphyromonas endodontalis. 2. The minimal inhibitory concentration(MIC) of polyphosphate was observed to be 0.04%. 3. Polyphosphates with chain lengths of 25 and 75 demonstrated the greatest inhibitory effect on the growth of Porphyromonas endodontalis. 4. Polyphosphates are bactericidal to Porphyromonas endodontalis, demonstrating the growth inhibition of the bacterium. The overall results suggest that use of polyphosphate may affect the growth of Porphyromonas endodontalis. Further studies will be needed to confirm the effect of, polyphosphate.

• Microbiology and Biotechnology Letters
• /
• v.47 no.1
• /
• pp.105-115
• /
• 2019

Saline or alkaline condition in soil inhibits growth of most crop plants and limits crop yields in many parts of the world. Augmenting an alkaline soil with alkali-tolerant bacteria capable of promoting plant growth can be a promising approach in expanding fertile agricultural land. Near-shore environments of Dokdo Island, a remote island located in the middle of the East Sea, appear to have patches of seawater-influenced haloalkaline soil that is unsupportive for growth of conventional plants. To exploit metabolic capacities of alkali-tolerant bacteria for promoting plant growth in saline or alkaline soils, we isolated of alkali-tolerant bacteria from near-shore soil samples in Dokdo and investigated properties of the isolates. Alkali-tolerant bacteria were selectively cultivated by inoculating suspended and diluted soil samples on a plate medium adjusted to pH 10. Fifty colonies were identified based on their $GTG_5$-PCR genomic fingerprints and 16S rRNA gene sequences. Most isolates were affiliated to alkali-tolerant and/or halotolerant genera or species of the phyla Firmicutes (68%), Proteobacteria (30%) and Actinobacteria (2%). Unlike the typical soil bacterial flora in the island, alkali-tolerant isolates belonged to only certain taxa of terrestrial origin under the three phyla, which have traits of plant growth promoting activities including detoxification, phytohormone production, disease/pest control, nitrogen-fixation, phosphate solubilization or siderophore production. However, Firmicutes of marine origin generally dominated the alkali-tolerant community. Results of this study suggest that haloalkaline environments like Dokdo shore soils are important sources for plant growth promoting bacteria that can be employed in bio-augmentation of vegetation-poor alkaline soils.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.19 no.1
• /
• pp.123-134
• /
• 2006

Objective : This experimental study was performed to investigate the effect of Herbe-medicine used for eye disease(Sean-tang, Jinpi-san, Tangpo-san, Copitdis Rhizoma) on Staphylococcus epidermidis keratitis. Methods : After administering various herbal eye drops on Staphylococcus epidermidis, I measured MIC and the size of inhibition zone. MIC was measured by dropping from 20 to $50{\mu}{\ell}$ according to density. Anti-bacterial potency was measured by the size of inhibition zone with change of volume under 2 days culture condition. Also continuous anti-bacterial potency of herbal eye drops was measured by the size of inhibition zone according to 2 days and 6 days culture each under the $50{\mu}{\ell}$ condition. Results : 1. MIC on Staphylococcus epidermidis in Sean-tang, Jinpi-san was 1%, $50{\mu}{\ell}$ 2. MIC on Staphylococcus epidermidis in Tangpo-san, Coptidis rhizoma was 10%, $50{\mu}{\ell}$ 3. MIC on Staphylococcus epidermidis in Cravit was 0.1%, $20{\mu}{\ell}$. 4. Under the 2 days culture condition, the size of inhibition zone on Staphylococcus epidermidis by volume for Sean-tang was 10.0mm in $50{\mu}{\ell}$, Jinpi-san was 16.0mm in $50{\mu}{\ell}$, Tangpo-san was 17.5mm in $50{\mu}{\ell}$, Coptidis rhizoma was 31.0mm in $50{\mu}{\ell}$ and Cravit was 34mm in $50{\mu}{\ell}$, showed the highest anti-bacterial potency. 5. Under the $50{\mu}{\ell}$ condition, the size of inhibition zone on Staphylococcus epidermidis by 2 and 6 culture days for Sean-tang was 47.5mm in 6days, Jinpi-san was 36.0mm in 6days, Tangpo-san was 45.0mm in 6 days and Cravit was 48.0mm in 6 days, which showed the highest anti-bacterial potency. 6. Under the $50{\mu}{\ell}$ culture condition, the size of inhibition zone on Staphylococcus epidermidis by 2 and 6 culture days for Coptidis rhizoma was 31.0mm in 2 days and 6 days, which showed the same anti-bacteria1 potency. Conclusions : The present author think that Herbe-medicine used for eye disease can be used to cure Staphylococcus epidermidis keratitis and if further study is performed, the use of the Herbe-medicine used for eye disease will be valuable and beneficial in the clinical medicines.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.8
• /
• pp.1169-1179
• /
• 2020

In this study, two soybean genotypes, i.e., aluminum-tolerant Baxi 10 (BX10) and aluminumsensitive Bendi 2 (BD2), were used as plant materials and acidic red soil was used as growth medium. The soil layers from the inside to the outside of the root are: rhizospheric soil after washing (WRH), rhizospheric soil after brushing (BRH) and rhizospheric soil at two sides (SRH), respectively. The rhizosphere bacterial communities were analyzed by high-throughput sequencing of V4 hypervariable regions of 16S rRNA gene amplicons via Illumina MiSeq. The results of alpha diversity analysis showed that the BRH and SRH of BX10 were significantly lower in community richness than that of BD2, while the WRH exhibited no significant difference between BX10 and BD2. Among the three sampling compartments of the same soybean genotype, WRH had the lowest community richness and diversity while showing the highest coverage. Beta diversity analysis results displayed no significant difference for any compartment between the two genotypes, or among the three different sampling compartments for any same soybean genotype. However, the relative abundance of major bacterial taxa, specifically nitrogen-fixing and/or aluminum-tolerant bacteria, was significantly different in the compartments of the BRH and/or SRH at phylum and genus levels, indicating genotype-dependent variations in rhizosphere bacterial communities. Strikingly, as compared with BRH and SRH, the WRH within the same genotype (BX10 or BD2) always had an enrichment effect on rhizosphere bacteria associated with nitrogen fixation.

• Journal of Korean Society of Forest Science
• /
• v.106 no.2
• /
• pp.121-129
• /
• 2017

The soil microbiome plays important roles in material cycling and plant growth in forest ecosystem. Although a lot of researches on forest soil fungi in Korea have been performed, the studies on forest soil bacterial communities have been limited. In this study, we conducted next generation sequencing (NGS) targeting 16S rRNA gene to investigate the soil bacterial communities from natural red pine (Pinus densiflora) forest in Mt. Janggunbong, Bonghwa-gun, Gyeongbuk, Korea. Our results showed that the entire bacterial communities in the study sites include the phyla Proteobacteria, Acidobacteria, Actinobacteria, Planctomycetes, which have been typically observed in forest soils. The composition ratio of Proteobacteria was the highest in the soil bacteria community. The results reflect that Proteobacteria is copiotroph, which generally favors relatively nutrient-rich conditions with abundant organic matter. Some rhizobia species such as Burkholderia, Bradyrhizobium, Rhizobium, which are known to contribute to soil nitrogen-fixation, exist in the study sites. As a result of correlation analysis between soil physicochemical characteristics and bacteria communities, the soil pH was significantly correlated with the soil bacteria compositions.