• Title/Summary/Keyword: D-arabinose

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Enhancement of Biocontrol Activity of Antagonistic Chryseobacterium Strain KJ1R5 by Adding Carbon Sources against Phytophthora capsici

  • Kim, Yu-Seok;Jang, Bo-Ra;Chung, Ill-Min;Sang, Mee-Kyung;Ku, Han-Mo;Kim, Ki-Deok;Chun, Se-Chul
    • The Plant Pathology Journal
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    • v.24 no.2
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    • pp.164-170
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    • 2008
  • Carbon utilization by Chryseobacterium strain KJ1R5 was studied to enhance its biocontrol activity against Phytophthora capsid. Chryseobacterium strain KJ1R5 has previously been shown to control Phytophthora blight of pepper (Capsicum annuum L.). Strain KJ1R5 could utilize carbon sources such as L-arabinose, D-cellobiose, ${\beta}-lactose$ and D-galactose well. P. capsici could utilize D-glucose well, showing the absorbencies ranged from 0.577 to 0.767 at 600nm. When 2% L-arabinose, which could only be utilized by the bio-control strain KJ1R5, was amended into the bacterial suspension, the efficacy of biological control increased. Among the amendments of various carbon sources into bacterial suspension, L-arabinose and D-(+)-glucose significantly enhanced biological control activity, resulting in a reduction of disease incidence to 6.9%, compared to 21.9% for the strain KJ1R5 alone and 81.3% for P. capsici inoculation alone, indicating that amendment with specific carbon sources could increase the biological control activity.

Metabolic engineering for isoprenoids production in Escherichia coli

  • Kim, Seon-Won;Keasling, J.D.
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.70-73
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    • 2001
  • Isopentenyl diphosphate (IPP) is the common, five-carbon building block in the biosynthesis of all isoprenoids. IPP in Escherichia coli is synthesized through the non-mevalonate pathway. The first reaction of IPP biosynthesis in E. coli is the formation of 1-deoxy-D-xylulose-5-phosphate(DXP), catalyzed by DXP synthase and encoded by dxs. The second reaction in the pathway is the reduction of DXP to 2-C-methyl-D-erythritol-4-phosphate, catalyzed by DXP reductoismerase and encoded by dxr. To determine if one of more of the reactions in the non-mevalonate pathway controlled flux to IPP, dxs and dxr were placed on several expression vectors under the control of three different promoters and transformed into three E. coli strains ($DH5{\alpha}$, XL1-Blue, and JM101) that had been engineered to produce lycopene, a kind of isoprenoids. Lycopene production was improved significantly in strains transformed with the dex expression vectors. At arabinose concentrations between 0 and 1.33 mM, cells expressiong both dxs and from $P_{BAD}$ on a midium-copy plasmid produced 1.4 -2.0 times more lycopene than cells expressing dxs only. However, at higher arabinose concentrations lycopene production in cell expressing both dxs and dxr was lower than in cells expression dxs only. A comparison of the three E. coli strains trasfomed with the arabinose-inducible dxs on a medium-copy plasmid revealed that lycopene production was highest in XL1-Blue.

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Microbial production of carotenoids for fortification of foods

  • Kim, Seon-Won;Keasling, J.D.
    • Proceedings of the Korean Society of Life Science Conference
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    • 2001.11a
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    • pp.3-8
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    • 2001
  • Isopentenyl diphosphate (IPP) is the common, five-carbon building block in the biosynthesis of all carotenoids, IPP in Escherichia coli is synthesized through the non-mevalonate pathway. The first reaction of IPP biosynthesis in E. coli is the formation of 1-deoxy-D-xylulose-5-phosphate (DXP), catalyzed by DXP synthase and encoded by dxs. The second reaction in the pathway is the reduction of DXP to 2-C-methyl-D-erythritol-4-phosphate, catalyzed by DXP reductoisomerase and encoded by dxr. To determine if one or more of the reactions in the non-mevalonate pathway controlled flux to IPP, dxs and dxr were placed on several expression vectors under the control of three different promoters and transformed into three E. coli strains (DH5(, XL1-Blue, and JM101) that had been engineered to produce lycopene. Lycopene production was improved significantly in strains transformed with the dxs expression vectors. When the dxs gene was expressed from the arabinose-inducible araBAD promoter (PBAD) on a medium-copy plasmid, lycopene production was 2-fold higher than when dxs was expressed from the IPTG-inducible trc and lac promoters (Ptrc and Plac, respectively) on medium-copy and high-copy plasmids, Given the low final densities of cells expressing dxs from IPTG-inducible promoters, the low lycopene production was probably due to the metabolic burden of plasmid maintenance and an excessive drain of central metabolic intermediates. At arabinose concentrations between 0 and 1.33 mM, cells expressing both dxs and dxr from PBAD on a medium-copy plasmid produced 1.4 - 2.0 times more lycopene than cells expressing dxs only. However, at higher arabinose concentrations lycopene production in cells expressing both dxs and dxr was lower than in cells expressing dxs only. A comparison of the three E. coli strains transformed with the arabinose-inducible dxs on a medium-copy plamid revealed that lycopene production was highest in XL1-Blue.

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Metabolic Engineering of Nonmevalonate Pathway in Escherichia coli Enhances Lycopene Production

  • Kim, Seon-Won;J.D. Keasling
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2001.06a
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    • pp.141-145
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    • 2001
  • Isopentenyl diphosphate (IPP) is the common, five-carbon building block in the biosynthesis of all carotenoids. IPP in Escherichia coli is synthesized through the non-mevalonate pathway. The first reaction of IPP biosynthesis in E. coli is the formation of l-deoxy-D-xylulose-5-phosphate (DXP), catalyzed by DXP synthase and encoded by dxs. The second reaction in the pathway is the reduction of DXP to 2-C-methyl-D-erythritol-4-phosphate, catalyzed by DXP reductoisomerase and encoded by dxr. To determine if one or more of the reactions in the non-mevalonate pathway controlled flux to IPP, dxs and dxr were placed on several expression vectors under the control of three different promoters and transformed into three E. coli strains (DH5$\alpha$, XL1-Blue, and JMl0l) that had been engineered to produce lycopene. Lycopene production was improved significantly in strains transformed with the dxs expression vectors. When the dxs gene was expressed from the arabinose-inducible araBAD promoter ( $P_{BAD}$) on a medium-copy plasmid, lycopene production was 2-fold higher than when dxs was expressed from the IPTG-inducible trc and lac promoters ( $P_{trc}$ and $P_{lac}$, respectively) on medium-copy and high-copy plasmids. Given the low final densities of cells expressing dxs from IPTG-inducible promoters, the low lycopene production was probably due to the metabolic burden of plasmid maintenance and an excessive drain of central metabolic intermediates. At arabinose concentrations between 0 and 1.33 roM, cells expressing both dxs and dxr from $P_{BAD}$ on a medium-copy plasmid produced 1.4 - 2.0 times more lycopene than cells expressing dxs only. However, at higher arabinose concentrations lycopene . production in cells expressing both dxs and dxr was lower than in cells expressing dxs only. A comparison of the three E. coli strains transformed with the arabinose-inducible dxs on a medium-copy plasmid revealed that lycopene production was highest in XLI-Blue.LI-Blue.

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Inhibitory Effect of Pentose on Biofilm Formation by Oral Bacteria

  • Lee, Young-Jong;Baek, Dong-Heon
    • International Journal of Oral Biology
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    • v.35 no.4
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    • pp.203-207
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    • 2010
  • A number of bacterial species coexist in oral cavities as a biofilm rather than a planktonic arrangement. By forming an oral biofilm with quorum sensing properties, microorganisms can develop a higher pathogenic potential and stronger resistance to the host immune system and antibiotics. Hence, the inhibition of biofilm formation has become a major research issue for the future prevention and treatment of oral diseases. In this study, we investigated the effects of pentose on biofilm formation and phenotypic changes using wild type oral bacteria obtained from healthy human saliva. D-ribose and D-arabinose were found to inhibit biofilm formation, but have no effects on the growth of each oral bacterium tested. Pentoses may thus be good candidate biofilm inhibitors without growth-inhibition activity and be employed for the future prevention or treatment of oral diseases.

Effect of Feeding Yogurt Using Enterococcus faecium KHM-11 on the Growth in Piglet (Enterococcus faecium KHM-11를 이용한 요구르트 급여가 자돈의 성장에 미치는 영향)

  • Bae, Hyoung-Churl;Lee, Jo-Yoon;Nam, Myoung-Soo
    • Food Science of Animal Resources
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    • v.28 no.2
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    • pp.204-210
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    • 2008
  • A total of 70 colonies were isolated from the Korean human milk samples on the BCP plate count agar. These LAB isolates were subcultured in 10% reconstituted skim milk, and two strain thereof were finally selected for their highest acid productions. These strains were identified as Enterococcusfaecium based on 16S rDNA sequencing data, named as Enterococcus faecium KHM-11. Sugar utilization of E. faecium KHM-11 was investigated by API 50CH kit, and 19 different sugars including D-arabinose, L-arabinose, galactose, D-glucose, D-fructose, and D-mannose were utilized. For fermentation profiles, a yogurt inoculated by E. faecium KHM-11 after 15 hour, reached at pH 4.09, titratable acidity at 1.10% and average viable counts $1.30{\times}10^9\;CFU/mL$. Effects of the administration of yogurt 0.5% of piglet diet to piglets were investigated for growth rate, analysis of blood and incidence of diarrhea. 24 heads of piglets were divided into two groups: the experimental and the control of 12 animals each. The average growth rate in the yogurt-fed group was higher for 21.67%, compared with control (p<0.05). There were no differences in the concentrations of blood glucose, cholesterol, albumin and globulin between the two treatments. Incidence of diarrhea was no in pigs fed yogurt as compare to control.

Protection of the brain through supplementation with larch arabinogalactan in a rat model of vascular dementia

  • Lim, Sun Ha;Lee, Jongwon
    • Nutrition Research and Practice
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    • v.11 no.5
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    • pp.381-387
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    • 2017
  • BACKGROUND/OBJECTIVES: Vascular dementia (VaD) caused by reduced blood supply to the brain manifests as white matter lesions accompanying demyelination and glial activation. We previously showed that arabinoxylan consisting of arabinose and xylose, and arabinose itself attenuated white matter injury in a rat model of VaD. Here, we investigated whether larch arabinogalactan (LAG) consisting of arabinose and galactose could also reduce white matter injury. MATERIALS/METHODS: We used a rat model of bilateral common carotid artery occlusion (BCCAO), in which the bilateral common carotid arteries were exposed and ligated permanently with silk sutures. The rats were fed a modified AIN-93G diet supplemented with LAG (100 mg/kg/day) for 5 days before and 4 weeks after being subjected to BCCAO. Four weeks after BCCAO, the pupillary light reflex (PLR) was measured to assess functional consequences of injury in the corpus callosum (cc). Additionally, Luxol fast blue staining and immunohistochemical staining were conducted to assess white matter injury, and astrocytic and microglial activation, respectively. RESULTS: We showed that white matter injury in the the cc and optic tract (opt) was attenuated in rats fed diet supplemented with LAG. Functional consequences of injury reduction in the opt manifested as improved PLR. Overall, these findings indicate that LAG intake protects against white matter injury through inhibition of glial activation. CONCLUSIONS: The results of this study support our hypothesis that cell wall polysaccharides consisting of arabinose are effective at protecting white matter injury, regardless of their origin. Moreover, LAG has the potential for development as a functional food to prevent vascular dementia.