Characterization of Ribose-5-Phosphate Isomerase B from Newly Isolated Strain Ochrobactrum sp. CSL1 Producing L-Rhamnulose from L-Rhamnose

( Min Shen ),( Xin Ju ),( Xinqi Xu ),( Xuemei Yao ),( Liangzhi Li ),( Jiajia Chen ),( Cuiying Hu ),( Jiaolong Fu ),( Lishi Yan ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.7

In this study, we attempted to find new and efficient microbial enzymes for producing rare sugars. A ribose-5-phosphate isomerase B (OsRpiB) was cloned, overexpressed, and preliminarily purified successfully from a newly screened Ochrobactrum sp. CSL1, which could catalyze the isomerization reaction of rare sugars. A study of its substrate specificity showed that the cloned isomerase (OsRpiB) could effectively catalyze the conversion of L-rhamnose to L-rhamnulose, which was unconventional for RpiB. The optimal reaction conditions (50oC, pH 8.0, and 1 mM Ca²⁺) were obtained to maximize the potential of OsRpiB in preparing L-rhamnulose. The catalytic properties of OsRpiB, including K_m, K_cat, and catalytic efficiency (K_cat/K_m), were determined as 43.47 mM, 129.4 sec^-1, and 2.98 mM/sec. The highest conversion rate of L-rhamnose under the optimized conditions by OsRpiB could reach 26% after 4.5 h. To the best of our knowledge, this is the first successful attempt of the novel biotransformation of L-rhamnose to L-rhamnulose by OsRpiB biocatalysis.

CFD simulation of an unbaffled stirred tank reactor driven by a magnetic rod: assessment of turbulence models

Li, Jiajia,Deng, Baoqing,Zhang, Bing,Shen, Xiuzhong,Kim, Chang Nyung IWA Publishing 2015 Water Science & Technology Vol.72 No.8

<P>A simulation of an unbaffled stirred tank reactor driven by a magnetic stirring rod was carried out in a moving reference frame. The free surface of unbaffled stirred tank was captured by Euler-Euler model coupled with the volume of fluid (VOF) method. The re-normalization group (RNG) k-epsilon model, large eddy simulation (LES) model and detached eddy simulation (DES) model were evaluated for simulating the flow field in the stirred tank. All turbulence models can reproduce the tangential velocity in an unbaffled stirred tank with a rotational speed of 150 rpm, 250 rpm and 400 rpm, respectively. Radial velocity is underpredicted by the three models. LES model and RNG k-epsilon model predict the better tangential velocity and axial velocity, respectively. RNG k-epsilon model is recommended for the simulation of the flow in an unbaffled stirred tank with magnetic rod due to its computational effort.</P>

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABA_A receptor expression

Chen, Huimin,Shen, Jiajia,Li, Haofeng,Zheng, Xiao,Kang, Dian,Xu, Yangfan,Chen, Chong,Guo, Huimin,Xie, Lin,Wang, Guangji,Liang, Yan The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/R+Rb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 × 10⁹ CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABA_A receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABA<SUB>A</SUB> receptor expression

Huimin Chen,Jiajia Shen,Haofeng Li,Xiao Zheng,Dian Kang,Yangfan Xu,Chong Chen,Huimin Guo,Lin Xie,Guangji Wang,Yan Liang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/RþRb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1×10<SUP>9</SUP> CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABAA receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABAA receptor expression

Huimin Chen,Jiajia Shen,Haofeng Li,Xiao Zheng,Dian Kang,Yangfan Xu,Chong Chen,Huimin Guo,Lin Xie,Guangji Wang,Yan Liang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exertsexcellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokineticsand pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects ofRb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 werecompared between conventional and PGF rats. The relative abundances of common probiotics werequantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressionsof the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (a2, b2, and g2) andGABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/RþRb1 rat hippocampus andstriatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relativeabundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgeryinduced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1b, IL-6, andTNF-a) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 109 CFU) by gavage 15d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministrationof a GABAA receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors ratherthan through direct distribution to the target sites.

A Study of Digit Recognition Algorithm for Meter based on Rough Set and Neural Network

Xiaochen Zhang,Yuanchang Zhong,Jiajia Shen,Kun Li,Congjun Feng 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.8

Due to the low recognition accuracy, the remote meter reading technology based on camera direct reading has been developed slowly. Although there is a variety of features data for recognizing digit in image using BP neural network, some of data cannot be used to recognize digit accurately. Moreover, the BP network has a slow rate of convergence, low accuracy and easily fall into local minimum. To solve the above questions, a new digit recognition algorithm of meter based on rough set and neural network which are optimized by genetic algorithm is proposed. The improved genetic rough set algorithm is used for reducing the data, and then the minimum feature attribute sets after reduction are input to genetic neural network for identifying digit. The experimental results show that the algorithm can effectively reduce the number of decision attributes and simplify the structure of the neural network with high identification accuracy and short training time, which improve the generalization ability and robustness of the neural network.

Effect of Bamboo and Rice Straw Biochars on the Bioavailability of Cd, Cu, Pb and Zn in Soils

Kouping Lu,Xing Yang,Jiajia Shen,Brett Robinson,Dan Liu,Hailong Wang 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Osmanthus fragrans Flower Extract and Acteoside Protect Against d-Galactose-Induced Aging in an ICR Mouse Model

Lina Xiong,Shuqin Mao,Baiyi Lu,Jiajia Yang,Fei Zhou,Yinzhou Hu,Yirong Jiang,Canxi Shen,Yajing Zhao 한국식품영양과학회 2016 Journal of medicinal food Vol.19 No.1

Osmanthus fragrans flower extract (OFE) is an organic extract from O. fragrans flower, which exhibits neuroprotective, free radical scavenging, and antioxidant effects. Therefore, the protective effect of OFE and acteoside against aging was studied. An aging ICR mouse model was established by chronically administering d-galactose (250 mg/kg) for 8 weeks. d-galactose induced spatial learning and memory impairments that were successfully inhibited by OFE and acteoside, which could shorten escape latency, improve platform crossing times, and increase zone time. The antioxidant potential of OFE and acteoside in vivo was evaluated by estimating the following: activities of antioxidant enzymes, such as glutathione peroxidase and aging-related enzyme, particularly monoamine oxidase; contents of lipid peroxidation methane dicarboxylic aldehyde, advanced glycation end products, and 8-hydroxy-2'-deoxyguanosine (a DNA damage product); and levels of nuclear factor-erythroid 2-related factor 2. OFE and acteoside also inhibited d-galactose-induced neurological aging by suppressing the increase in glial fibrillary acidic protein and neurotrophin-3. Considering the dose-dependent protective effects of OFE and acteoside, we concluded that OFE, rich in acteoside, was a good source of natural antiaging compounds.