• 한국축산식품학회지
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• 제32권4호
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• pp.409-413
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• 2012

This study aimed to compare the probiotic characteristics of twelve strains of Lactobacillus acidophilus including cholesterol assimilation and conjugated linoleic acid (CLA) production. Cholesterol assimilation exhibited some variation among L. acidophilus strains, which could be classified into three groups based on their assimilation levels (p<0.05). The high cholesterol assimilation group exhibited a significantly higher tolerance to 0.3 and 0.5% bile acid than the low cholesterol assimilation group (p<0.05). Cholesterol assimilation showed positive correlation with 0.5% bile tolerance, and a negative correlation with acid tolerance (p<0.01). Glycocholate deconjugation activity showed no relationship with cholesterol assimilation, whereas taurocholate deconjugation activity was shown to have negative correlation with cholesterol assimilation (p<0.05). CLA production by L. acidophilus strains exhibited a wide variation, ranging from 2.69 to 5.04 mg/g fat. CLA production of L. acidophilus GP1B was the highest among the tested strains, but there was no evidence for differences in CLA production in strain specificity. Based on these results, the cholesterol assimilation of L. acidophilus strains may not be related to deconjugation activity, but may in-fact be attributed to their bile-tolerance.

• Food Science and Biotechnology
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• 제17권2호
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• pp.257-261
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• 2008

Previous studies have suggested a possible correlation between cell surface hydrophobicity (CSH) and stress tolerance in Bifidobacterium. In this study, the relationship was examined between CSH and environmental stress tolerance in Lactobacillus spp. By measuring the adhesion to hexadecane, 2 Lactobacillus fermentum strains- KLB 261 and KLB 231 were found to have high and low CSH, respectively. To measure their tolerance to various stresses, cells were subjected to salt (2 M NaCl), acid (pH 2), $H_2O_2$ (0.01 %, v/v), ethanol (20%, v/v), heat ($60^{\circ}C$), and cold ($-20^{\circ}C$). Compared with KLB 231, the hydrophobic KLB 261 was found to be much more resistant to the various stresses examined. After being subjected to different stresses for a period of time, KLB 261 and KLB 231 showed 50 and 0% survivability in 2 M NaCl, 108.2 and 0.6% in 0.01 %(v/v) $H_2O_2$, 40.2%(v/v), and 3.7% at $60^{\circ}C$ incubation, 4 and 0.6% at $-20^{\circ}C$, 12.9 and 0.1 % in pH 2, 33.8 and 0.2% in 20%(v/v) ethanol, respectively. Autoaggregation test and morphological observation were also conducted in an attempt to explain these differences. These results suggested that high CSH could strengthen the stress tolerance of lactobacilli.

• Genes and Genomics
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• 제40권11호
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• pp.1199-1211
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• 2018

Soil acidification is one of major problems limiting crop growth and especially becoming increasingly serious in China owing to excessive use of nitrogen fertilizer. Only the STOP1 of Arabidopsis was identified clearly sensitive to proton rhizotoxicity and the molecular mechanism for proton toxicity tolerance of plants is still poorly understood. The main objective of this study was to investigate the transcriptomic change in plants under the low pH stress. The low pH as a single factor was employed to induce the response of the wheat seedling roots. Wheat cDNA microarray was used to identify differentially expressed genes (DEGs). A total of 1057 DEGs were identified, of which 761 genes were up-regulated and 296 were down-regulated. The greater percentage of up-regulated genes involved in developmental processes, immune system processes, multi-organism processes, positive regulation of biological processes and metabolic processes of the biological processes. The more proportion of down-regulation genes belong to the molecular function category including transporter activity, antioxidant activity and molecular transducer activity and to the extracellular region of the cellular components category. Moreover, most genes among 41 genes involved in ion binding, 17 WAKY transcription factor genes and 17 genes related to transport activity were up-regulated. KEGG analysis showed that the jasmonate signal transduction and flavonoid biosynthesis might play important roles in response to the low pH stress in wheat seedling roots. Based on the data, it is can be deduced that WRKY transcription factors might play a critical role in the transcriptional regulation, and the alkalifying of the rhizosphere might be the earliest response process to low pH stress in wheat seedling roots. These results provide a basis to reveal the molecular mechanism of proton toxicity tolerance in plants.

• 한국작물학회지
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• 제43권4호
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• pp.234-238
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• 1998

To select new germplasm for salinity tolerance from new plant type (NPT) breeding lines, the sixty F$_4$ lines selected from the crosses between Korean cultivars and IRRI's NPT lines were evaluated for salinity tolerance at the seedling stage with salinized culture solution (EC=12 dS/m) in the controlled conditions. Two NTP lines derived from a cross between 'Ilmibyeo' and 'IR66152-AC5-1', 'HR15258-7-1' and 'HR15258-27-1', were found to have good tolerance. The salinity tolerance of the lines was compared to their parents and the sensitive ('IR29') and tolerant ('Pokkali') checks in three salinity levels, no salinity (control) and an EC of 12 and 16 dS/m. Visual salinity score, shoot Na+ and Na-K ratio in two NPT lines was significantly low compared with the parents and IR29. Indicating that salinity tolerance of the lines might be derived from a transgressive segregation. The relative water content of the lines was higher than Pokkali, and the dry weight of shoot and root was proportionally decreased to salinity score and salinizing concentration. The visual salinity scores were significantly correlated with shoot Na concentration, Na-K ratio, relative water content, and reduction of dry weight (P<0.01). Their tolerance was attributed to root and shoot characteristics that led to high shoot water content, thus diluting the toxic effect of salts.

• 한국산림과학회지
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• 제79권1호
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• pp.26-32
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• 1990

기내(器內)에서 배양(培養)된 5수종(樹種)의 Populus 류(類)(P. davidiana, P. maximowiczii, P. nigra, P. alba ${\times}$ P. glandulosa, P. nigra ${\times}$ P. maximowiczii)의 줄기를 Aluminium-EDTA가 0, 0.1, 0.2, 0.5, 1.0mM씩 첨가(添加)된 배지(培地)에 배양(培養)시켜 뿌리, 줄기, 잎의 생육(生育)상태를 조사(調査)하여 aluminium 내성(耐性)을 비교 분석하였다. 수종간(樹種間) Aluminium내성(耐性)의 차이(差異)는 비교적(比較的) 심(甚)하게 나타났고, 조사(調査)한 5수종중(樹種中) 사시나무가 가장강한 내성(耐性)을 지닌것으로 나타났다. Al-EDTA가 낮은 농도(濃度)로 첨가(添加)된 배지(培地)에서는 줄기와 뿌리생장에 촉진효과를 나타내는 종도 있었다. 1.0mM의 고농도(高濃度)에서는 사시나무 이외의 수종(樹種)에서는 발근(發根)이 억제되었다. 양버들, 황철, 현사시와 같은 내성(耐性)이 약(弱)한 수종(樹種)에서는 0.1mM의 낮은 농도(濃度)에서도 잎과 줄기에 형태적(形態的)인 변이현상이 나타났다. 양황철은 그 양친(兩親)인 양버들이나 황철보다 줄기생장(生長)에서 내성(耐性)이 증가했다.

• Journal of Microbiology and Biotechnology
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• 제31권6호
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• pp.840-846
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• 2021

To improve the bile salt and acid tolerance of probiotics against gastrointestinal stresses, we investigated the effects of soybean lecithin and whey protein concentrate (WPC) 80 on the bile salt tolerance of Lacticaseibacillus paracasei L9 using a single-factor methodology, which was optimized using response surface methodology (RSM). The survival rate of L. paracasei L9 treated with 0.3% (w/v) bile salt for 2.5 h, and combined with soybean lecithin or WPC 80, was lower than 1%. After optimization, the survival rate of L. paracasei L9 incubated in 0.3% bile salt for 2.5 h reached 52.5% at a ratio of 0.74% soybean lecithin and 2.54% WPC 80. Moreover, this optimized method improved the survival rate of L. paracasei L9 in low pH condition and can be applied to other lactic acid bacteria (LAB) strains. Conclusively, the combination of soybean lecithin and WPC 80 significantly improved the bile salt and acid tolerance of LAB. Our study provides a novel approach for enhancing the gastrointestinal tolerance of LAB by combining food-derived components that have different properties.

• 생명과학회지
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• 제9권2호
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• pp.169-175
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• 1999

Salmonella typhimurum은 생활사 동안에 다양한 환경과 접하게 된다. S. typhimurium은 오염된 웅덩이에서 숙주의 phgolysosome에 이르기까지 생태계에 널리 분포하면서 산성 스트레스를 경험하며 또한 생존할 수 있다. Salmonella 이와 같은 산저항능은 Acid Tolerance Response (ATR)에 의해 획득된다. 약산의 pH에 적응된 S. typhimurium은 낮은 pH 영역에서 생존할 수 있는 일종의 대항능을 갖게되며, 이런 생존 능력은 복잡한 유전적 유도현상 결과로 해석된다. Salmonella 있어서 ATR은 RpoS 의존적 그리고 RpoS 비의존적 현상으로 구분되며, 특히 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)에서 rpoS$\Omega$Ap는 UK1과 동일한 ATR을 나타내어, 혐기적 조건의 ATR은 RpoS 비의존적인 것으로 판명되었다. P22와 MudJ (Km, lacZ)를 이용한 gene fusion기법과 sodium acetate (pH4.5)를 이용한 돌연변이체 분리방법을 병행하여 산민감성의 형질을 나타내는 LE487 aatA::MudJ를 얻었다. antA 는 Salmonella의 유전자 지도상에서 12min에 위치하는 것으로 조사되었다. antA는 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)하의 pH4.3 조건에서 야생형 Salmonella 비해서 매우 높은 산민감성을 보여주었다. 그러므로 antA는 혐기적 ATR에 있어서 산적응 기전에 관여하는 중요한 유전자로 확인되었다.

• Plant Breeding and Biotechnology
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• 제1권1호
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• pp.1-8
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• 2013

Low-temperature stress is an important factor controlling the growth and development of rice (Oryza sativa L.) in temperate region. In this study, a molecular linkage map consisting of 136 SSR markers was employed to identify QTL associated with cold tolerance at the seedling stage. 80 recombinant inbred lines (RILs) from an intersubspecific cross between Milyang23 (O. sativa ssp. Indica) and Hapcheonaengmi3, a japonica weedy rice and the parents were evaluated for leaf discoloration and SAPD value of seedlings. Rice plants were grown for 15 days in the low-temperature condition (13/20℃ day/night) and the control condition (25/20℃ day/night) in the growth chamber. The degree of leaf discoloration showed a highly significant correlation with the SPAD value in the low-temperature plot (r = -0.708, P < 0.0001). A total of four QTLs for SPAD were identified and the phenotypic variance explained by each QTL ranged from 5.4 to 16.0%. Two QTLs detected in the control condition were located on chromosomes 2 and 5, respectively. Two QTL on chromosomes 1 and 4 were detected at the low-temperature condition and Hapcheonaengmi3 alleles increased the SPAD values at these loci. Substitution mapping was conducted to delimit the position of qSPA-4 using introgression lines derived from the same cross. Results indicated that qSPA-4 was located in a 810-Kb region flanked by RM16333 and RM16368. The results indicated that Hapcheonaengmi3 contains QTL alleles that are likely to improve cold tolerance of Indica rice.

• 한국어병학회지
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• 제16권2호
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• pp.119-123
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• 2003

We have selected an valuable pmbiotic strain; Lactobacillus sakei BK19 which has wide antagonic spectrum against fish pathogens . Present study investigated cultural characterization of L. sakei BK19 including pH tolerance , susceptibility of antibacterial agents and growth pattern with different environment such as nutritions, temperature and salinity. L. sakei BK19 showed Significantly higher resistance at low pH(around pH 4) environment and relative high antibiotic tolerance . In the study of optimal culture condition, maltose and saccharose provided the optimal nutritional culture condition while lactose and mannitol were unable to supply its carbon source for the fermentation of L. sakei BK19. Moreover. L. sakei BK19 showed good growth at the temperature range of 15 to $45^{o}C$ und the NaCl concentration of 0 to 7%. Hence, this particular probiotic strain may be benificial both in seawater and fresh weter conditions.

• 한국산림과학회지
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• 제4권1호
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• pp.33-38
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• 1965

It has already been noted that some tree species, denoted as tolerant species, endure to behavior shadiness in growth than those species, denoted as intolerant species, since this fact of tolerance must be involved in silvicultural practice, the present author, with pinus rigida, pinus Thunbergii, and Buxus koreana, investigated the relation of degree of shadiness to soil moisture condition. Because tolerant and intolerant trees must be considered from the standpoint of their ability to use any of the factors that are likely to be at low concentration in the dense or open forest. The observed results may be summarized as follows : 1. The ability of tolerance of the species to shadiness is differently concluded by the base with which the analysis was made, i.c. Height, growth, diameter growth, T-R ratio or dry matter increase and so on. Regarding this point root collar increment or dry matter increase were considered more reasonable bases for discussing the tolerability. 2. When total length growth, including both stem and root, is taken as standard for the comparison of the ability of tolerance for each species, higher soil moisture condition and thicker shadeniss lessened the ability of pinus rigida, seedlings. Pinus Thunbergii, showed. However more moisture resistant than pinus rigida. Buxus koreana, seemed to have stronger ability of tolerance than any others. 3. When total dry matter content taken as standard, the results obtained are given in Fig, 3. In pinus rigida, the soil moisture supplemented the lack of light.