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Juan Zhang,Chongde Wu,Guocheng Du,Jian Chen 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2
This study aimed to improve the acid tolerance of Lactobacillus casei Zhang and compare the stress response of the parental strain and the acid-resistant mutant during acidic conditions. Adaptive evolution was conducted for 70 days to generate acid-tolerant L. casei. The evolved mutant lb-2 exhibited more than a 60% increase in biomass as well as a 13.6 and 65.6% increase in concentrations of lactate and acetate, respectively, when cultured at pH 4.3 for 64 h. Lactic acid tolerances of the parental strain and the evolved mutant were determined. As a result,the evolved mutant showed a 318-fold higher survival rate than that of the parental strain. Physiological analysis showed that the evolved mutant exhibited higher intracellular pH (pHi), NH4+ concentration and lower inner membrane permeability than that of the parental strain during acid stress. Moreover, higher amounts of intracellular arginine and aspartate were also detected in lb-2under acid stress. Validation of the relationship between the acid tolerance and the intracellular arginine and aspartate accumulation was conducted by experiments that showed the survival of L. casei at pH 3.3 was improved 1.36-,2.10-, or 3.42-fold by the addition of 50 mM aspartate,arginine or both of them, respectively. Taken together,results presented here not only supply an effective way to select acid-resistant strains for the food industry, but also contribute to reveal the mechanisms of acid tolerance and provide new strategies to enhance the industrial utility and health-promoting properties of this species.
The treatment effect of novel hGHRH homodimer to male infertility hamster
Zhang, Xu-Dong,Guo, Xiao-Yuan,Tang, Jing-Xuan,Yue, Lin-Na,Zhang, Juan-Hui,Liu, Tao,Dong, Yu-Xia,Tang, Song-Shan The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.6
Extra-hypothalamic growth hormone-releasing hormone (GHRH) plays an important role in reproduction. To study the treatment effect of Grin (a novel hGHRH homodimer), the infertility models of 85 male Chinese hamsters were established by intraperitoneally injecting 20 mg/kg of cyclophosphamide once in a week for 5 weeks and the treatment with Grin or human menopausal gonadotropin (hMG) as positive control was evaluated by performing a 3-week mating experiment. 2-8 mg/kg of Grin and 200 U/kg of hMG showed similar effect and different pathological characteristics. Compared to the single cyclophosphamide group (0%), the pregnancy rates (H-, M-, L-Grin 26.7, 30.8, 31.3%, and hMG 31.3%) showed significant difference, but there was no difference between the hMG and Grin groups. The single cyclophosphamide group presented loose tubules with pathologic vacuoles and significant TUNEL positive cells. Grin induced less weight of body or testis, compactly aligned tubules with little intra-lumens, whereas hMG caused more weight of body or testis, enlarging tubules with annular clearance. Grin presented a dose-dependent manner or cell differentiation-dependentincrease in testicular GHRH receptor, and did not impact the levels of blood and testicular GH, testosterone. Grin promotes fertility by proliferating and differentiating primitive cells through up-regulating testicular GHRH receptor without triggering GH secretion, which might solve the etiology of oligoasthenozoospermia.
Juan Zhang,Yanqiu Cai,Guocheng Du,Jian Chen,Miao Wang,Zhen Kang 한국미생물학회 2017 The journal of microbiology Vol.55 No.7
Cutinase as a promising biocatalyst has been intensively studied and applied in processes targeted for industrial scale. In this work, the cutinase gene tfu from Thermobifida fusca was artificially synthesized according to codon usage bias of Saccharomyces cerevisiae and investigated in Saccharomyces cerevisiae. Using the α-factor signal peptide, the T. fusca cutinase was successfully overexpressed and secreted with the GAL1 expression system. To increase the cutinase level and overcome some of the drawbacks of induction, four different strong promoters (ADH1, HXT1, TEF1, and TDH3) were comparatively evaluated for cutinase production. By comparison, promoter TEF1 exhibited an outstanding property and significantly increased the expression level. By fed-batch fermentation with a constant feeding approach, the activity of cutinase was increased to 29.7 U/ml. The result will contribute to apply constitutive promoter TEF1 as a tool for targeted cutinase production in S. cerevisiae cell factory.
Juan Zhang,Shifeng Li 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7
In the paper, we apply a structure-preserving doubling algorithm to solve the continuous coupled algebraic Riccati equation (CCARE). Using the existence and uniqueness of the CCARE, we show that the iteration solution of the CCARE are positive semi-definite, symmetric, and unique. Further, we discuss the convergent analysis of the structure-preserving doubling algorithm. Moreover, we present two modified structure-preserving doubling algorithms. Finally, we offer corresponding numerical examples to illustrate the effectiveness of the derived numerical algorithms.
RPSA Gene Mutants Associated with Risk of Colorectal Cancer among the Chinese Population
Zhang, Shan-Chun,Jin, Wen,Liu, Hui,Jin, Ming-Juan,Chen, Ze-Xin,Ding, Zhe-Yuan,Zheng, Shuang-Shuang,Wang, Li-Juan,Yu, Yun-Xian,Chen, Kun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12
The primary aim of this study was to evaluate the relationship of single nucleotide polymorphisms (SNPs) in ribosomal protein SA (RPSA) gene with colorectal cancer (CRC). A case-control study including 388 controls and 387 patients with CRC was conducted in a Chinese population. Information about socio-demography and living behavior factors was collected by a structured questionnaire. Three SNPs (rs2133579, rs2269349, rs7641291) in RPSA gene were genotyped by Illumina SnapShot method. Multiple logistic regression models were used for assessing the joint effects between tea consumption and SNPs on CRC. The subjects with rs2269349 CC genotype had a decreased risk for CRC (OR=0.60; 95%CI = 0.37-0.99), compared with TT/CT genotype after adjustment for covariates. A similar association of rs2269349 with rectal cancer was observed (OR=0.49; 95%CI=0.24-1.00). Further analyses indicated that this SNP could modify the protective effect of tea drinking on CRC. Among the subjects with rs2269349 TT/CT or rs2133579 AA/GA, there was a marginal significantly lower risk of CRC (OR and 95%CI: 0.63 and 0.39-1.01 for rs2269349; 0.64 and 0.40-1.02 for rs2133579) in tea-drinking subjects in comparison to non-tea-drinking subjects. Mutants in the RPSA gene might be associated with genetic susceptibility to CRC and influence the protective effect of tea consumption in the Chinese population.
Discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins
Juan Liu,Yangrong Xu,Jingjing Yang,Wenzhi Wang,Jianqiang Zhang,Renmei Zhang,Qingguo Meng 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3
Ocotillol-type saponins are one kind of tetracyclic triterpenoids, sharing a tetrahydrofuran ring. Natural ocotillol-type saponins have been discovered in Panax quinquefolius L., Panax japonicus, Hana mina, and Vietnamese ginseng. In recent years, the semisynthesis of 20(S/R)-ocotillol-type saponins has been reported. The biological activities of ocotillol-type saponins include neuroprotective effect, antimyocardial ischemia, antiinflammatory, antibacterial, and antitumor activities. Owing to their chemical structure, pharmacological actions, and the stereoselective activity on antimyocardial ischemia, ocotillol-type saponins are subjected to extensive consideration. In this review, we sum up the discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins.