• KSBB Journal
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• v.32 no.2
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• pp.153-159
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• 2017

The purpose of this study was to investigate the probiotic properties of lactic acid bacterial strains isolated from human feces. The properties were tested on the basis of guideline for probiotic selection protocol such as tolerance for acid or bile salt, autoaggregation, antibiotic resistance, and antimicrobial activity. Total 25 lactic acid bacteria were isolated from human feces, and their antibacterial activity was tested against Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Vibrio parahaemolyticus, V. alginolyticus using an agar diffusion assay. Among them, 4 selected strains were identified by analysis of their 16S rRNA, as Lactobacillus rhamnosus MG316, L. acidophilus MG501, L. reuteri MG505, and L. gasseri MG570. Results show that resistance to low pH and bile salts. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All strains tested were resistance to nalidixic acid and kanamycin.

• Journal of Life Science
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• v.10 no.6
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• pp.598-604
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• 2000

This study was conducted to investigate the effect of simulated acid rain (SAR) on germination, growth, acid buffering capacity and nutrient leaching in Impatiens balsamina L. and Tagetes patula L.. In both species, germination was not inhibited at pH 4.0, but the germination rate decreased at the lower pH of 3.0, showing higher rate in Inpatiens balsamina L. than Tagetes patula L.. As the pH decreases, the growth of radicle was markedly decreased than that of hypocotyl in both species. The plant height, root length, leaf area, total dry weight, relative growth rate and net assimilation rate were inhibited by SAR. The acid buffering capacity in the leaves were increased at pH 4.0, on the other hand, it was shown a tendency to decrease at pH 2.0 in both species. As the pH levels decreased from 5.6 to 2.0, the nutrient leaching from leaves was significantly increased in both species. Based on the results, there are a great difference in the responses to SAR between the two species. In general, Tagetes patula L. represented a higher tolerance to SAR than Impatiens balsamina L.. These results suggested that interspecific variation in the acid buffering capacity and nutrient leaching from leaves may be responsible for the interspecific susceptibility to SAR.

• Journal of Life Science
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• v.11 no.3
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• pp.197-202
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• 2001

This study was conducted to investigate the effect of simulated acid solution(SAS) on acid buffering capacity, chlorophyll content and butrient leacking in 4 herb species(Petunia hybrida Vilm, Gomphrena globosa L. Celosia cristat L. Salvia officinallis L) . The acid buffering capacity in the leves was increased in the treatment of pH 3.0 in Celosia L., whereas it was increased at pH 4.0 in Petunia Petunia hybrida Vilm. and Gomprean globosa L.. But, the acid buffering capacity of the leaves did not work at ph 2.0 treatment in 4 herb species. With decreasing pH level, the chlorophyll content of Petunia hybrida Vilm. and Gomphrena globosa L. Was markedly decreased than that of Gelosia cristata L. and Savia officinalis L. As the pH levels decreased from 5.6 to 2.0 the nutrient leaching from leaves was significantly increased in 4 herb species. In pH 4.0 and 5.6, the concentrations of nutrient leaching from leaves were higher in Perunia hybrida Vilm. and Gomphrean globosa L. than Gelosia cristata L. and Salvia officinalis L., Based on the results, there was a great differences in response to SAS among the 4 herb species. Im general, Gelosia cristata L. and Salvia officinalis L. represented a higher tolerance to SAS Petunia hybrida Vilm, and Gomphrena globosa L..

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.116-122
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• 2002

Dehydrins (LEA Dll proteins) are one of the typical families of plant proteins that accumulate in response to dehydration, cold stress, abscisic acid, or during seed maturation. A 1.3-kb cDNA was cloned from a cDNA expression library of 5-day-old germinating maize scutellums under drought stress. The deduced protein sequence indicated a dehydrin gene encoding SK$_3$ LEA protein typically expressed during cold acclimation, but not by drought stress in barley and wheat. Thus, it was named maize DEHYDRIN2 (ZmDhn2). It accumulates rapidly and highly in drought-stressed scutellum and leaf tissues at any stage, but not under cold stress. ZmDhn2 gene was transformed into Arabidopsis thaliana for functional analysis under drought condition. From electrolyte leakage test, no significant difference showed between wild type and transformants under normal growth condition, but the leakage level of electrolyte in wild type plants was about 3 times as high as that in the transformed plants under drought stress. It suggests that ZmDHN2 playa role in increasing drought tolerance.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.581-586
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• 2004

The growth characteristics and the properties of the Enterococcus faecium (E. faecium) isolated from intestine of slaughting pig were examined in order to confirm whether it will be used practically as probiotics or not. E. faecium was identified by morphological and biochemical tests including of final confirming by API strep kit. Among 264 samples, 44 isolates (16.7%) of E. faecium were observed as an exellent growth as a range of $1{\times}10^7CFU/ml{\sim}3.3{\times}10^9CFU/ml$ in viable bacterial count on MRI medium. All isolates were shown non-haemolysis on the blood agar exception of 28 isolates shown ${\alpha}$-haemolysis and were identified as E. faecium by biochemical test using API strep enzyme kits. Eight strains (18.2%) were finally selected from which they were excellent sensitivity in showing of the acid-tolerance and the bile-tolerance in compare with reference strain.

• KSBB Journal
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• v.32 no.3
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• pp.199-205
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• 2017

The aim of this study was to investigate probiotic characteristics and fermentation profile of selected lactic acid bacteria (LAB) isolated from traditional fermented foods. Antibacterial activity against various pathogens, acid and bile salt tolerance, cell hydrophobicity, and antibiotic resistance were examined. 16S rRNA sequencing was carried out to identify eight presumptive LAB isolates. In general, all identified LAB (Enterococcus faecium MG89-2, Lactobacillus plantarum MG207, L. paracasei MG310, L. casei MG311, Streptococcus thermophilus MG510, L. bulgaricus MG515, L. helveticus MG585, and L. fermentum MG590) showed strong antimicrobial activity. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All selected strains tested were sensitive to chloramphenicol, tetracycline, and ampicillin, whereas resistant to nalidixic acid and kanamycin.

• The Plant Pathology Journal
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• v.37 no.5
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• pp.415-427
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• 2021

A plethora of compounds stimulate protective mechanisms in plants against microbial pathogens and abiotic stresses. Some defense activators are synthetic compounds and trigger responses only in certain protective pathways, such as activation of defenses under regulation by the plant regulator, salicylic acid (SA). This review discusses the potential of naturally occurring plant metabolites as primers for defense responses in the plant. The production of the metabolites, hexanoic acid and melatonin, in plants means they are consumed when plants are eaten as foods. Both metabolites prime stronger and more rapid activation of plant defense upon subsequent stress. Because these metabolites trigger protective measures in the plant they can be considered as "vaccines" to promote plant vigor. Hexanoic acid and melatonin instigate systemic changes in plant metabolism associated with both of the major defense pathways, those regulated by SA- and jasmonic acid (JA). These two pathways are well studied because of their induction by different microbial triggers: necrosis-causing microbial pathogens induce the SA pathway whereas colonization by beneficial microbes stimulates the JA pathway. The plant's responses to the two metabolites, however, are not identical with a major difference being a characterized growth response with melatonin but not hexanoic acid. As primers for plant defense, hexanoic acid and melatonin have the potential to be successfully integrated into vaccination-like strategies to protect plants against diseases and abiotic stresses that do not involve man-made chemicals.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.783-791
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• 2022

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 ㎍/ml, while it was 1812.16 ± 23.16 ㎍/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.556-563
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• 1994

To compare the tolerance of crops to acid rain of simulated acid rains(SAR) of three pH levels (3.0, 4.5, and 6.0) were applied to rice, corn, soybean, adzuki bean, hot pepper, tomato, sesame, barley, wheat, Chinese cabbage, radish, lettuce, and spinach for 30 days from 20 days after emergence at two-day interval with 10mm at a time. No visual damages were observed. Also, no alteration of ultrastructure was observed although some lightly stained lipid granules were observed in the chloroplasts of sesame, soybean, and adzuki bean at the SAR treatment of pH 3.0. As pH of SAR decreased, chlorophyll content increased in adzuki bean, decreased in rice, tomato, and spinach, and similar in the other crops. Photosynthetic activity of adzuki bean increased, while decreased in Chinese cabbage and barley as pH of SAR decreased, and similar in other crops. Concentration and uptake of N were not affected by SAR treatments in all crops except tomato and barley. When a strong SAR of pH 2.0 was applied, rice, corn, sesame, tomato, barley, and wheat were relatively tolerant, while adzuki bean, hot pepper, soybean, Chinese cabbage, lettuce, radish, and spinach were susceptible in terms of visual damages.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.62-70
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• 2020

Zygosaccharomyces rouxii is an important yeast that is required in the food fermentation process due to its high salt tolerance. In this study, the responses and resistance strategies of Z. rouxii against salt stress were investigated by performing physiological analysis at membrane level. The results showed that under salt stress, cell integrity was destroyed, and the cell wall was ruptured, which was accompanied by intracellular substance spillover. With an increase of salt concentrations, intracellular Na⁺ content increased slightly, whereas intracellular K⁺ content decreased significantly, which caused the increase of the intracellular Na⁺/K⁺ ratio. In addition, in response to salt stress, the activity of Na⁺/K⁺-ATPase increased from 0.54 to 2.14 μmol/mg protein, and the ergosterol content increased to 2.42-fold to maintain membrane stability. Analysis of cell membrane fluidity and fatty acid composition showed that cell membrane fluidity decreased and unsaturated fatty acid proportions increased, leading to a 101.21% rise in the unsaturated/saturated fatty acid ratio. The results presented in this study offer guidance in understanding the salt tolerance mechanism of Z. rouxii, and in developing new strategies to increase the industrial utilization of this species under salt stress.