Safety Evaluation of Lactobacillus paracasei subsp. paracasei LC-01,a Probiotic Bacterium

Hao Zhang,Yu Wang,Jing Sun,Zirui Guo,Huiyuan Guo,Fazheng Ren 한국미생물학회 2013 The journal of microbiology Vol.51 No.5

The safety of Lactobacillus paracasei subsp. paracasei LC-01was evaluated for its use as a potential probiotic. In our in vitro study, the antibiotic resistance and the ability to produce biogenic amine were determined. The results showed that the strain was sensitive to all tested antibiotics and did not produce biogenic amine except for tyramine. The oral toxicity of this strain was evaluated in Balb/C mice. One hundred mice were divided into 10 groups. Four groups were administered 0, 108, 109, or 1010 CFU/mouse per day dissolved in saline solution respectively, for 28 days. Three groups were injected intraperitoneally with 109 CFU/mouse dissolved in saline solution, and were killed 2, 5, and 10 days after injection. The last 3 groups were injected with the vehicle as controls respectively. The results showed that oral administration of the strain had no adverse effects on mouse body weight and that there was no treatment-associated bacterial translocation. Intraperitoneal administration caused a significant translocation to liver, spleen and kidney. However,this translocation did not cause illness or death throughout the experiment. The results suggest that L. paracasei subsp. paracasei LC-01 is likely to be safe for human consumption.

Lactobacillus paracasei subsp. paracasei LC01 Positively Modulates Intestinal Microflora in Healthy Young Adults

Hao Zhang,Jing Sun,Xianting Liu,Chuan Hong,Yuanbo Zhu,Aiping Liu,Siqi Li,Huiyuan Guo,Fazheng Ren 한국미생물학회 2013 The journal of microbiology Vol.51 No.6

Lactobacillus paracasei subsp. paracasei LC01 (LC01) can tolerate intestinal stresses and has antioxidant activity. To evaluate the effect of the bacterium on human intestinal microflora,a randomized, double-blind, placebo-controlled human trial was carried out. Fifty-two healthy adult volunteers were randomized equally to two groups. One group consumed 12% (wt/vol) skimmed milk supplemented with 1010 CFU of LC01 each day for the 4-week treatment period,and then consumed placebo in the next treatment period,separated by a 2-week washout. The other group followed the reverse order. Group-specific real-time PCR and biochemical analyses was used to determine the intestinal bacterial composition of fecal samples collected at the end of every period, and the concentration of short-chain fatty acids and ammonia. A significant inhibition in fecal Escherichia coli and increase in Lactobacillus, Bifidobacterium, and Roseburia intestinalis were observed after consumption of LC01. Acetic acid and butyric acid were significantly higher in the probiotic stage and fecal ammonia was significantly lower. The results indicated a modulation effect of LC01 on the intestinal microflora of young adults, suggesting a beneficial effect on bowel health. LC01 may have potential value as a probiotic.

Dynamics of Bacterial Communities of Lamb Meat Packaged in Air and Vacuum Pouch during Chilled Storage

Taojun Wang,Huiyuan Guo,Hao Zhang,Fazheng Ren,Ming Zhang,Shaoyang Ge,Hailing Luo,Liang Zhao 한국축산식품학회 2019 한국축산식품학회지 Vol.39 No.2

In this study, the changes in microbial communities of lamb meat packaged in the air (plastic tray, PT) and in a vacuum pouch (VAC) were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) during the storage at 4°C. For the PT lamb, the total viable count (TVC) was 107 CFU/g on Day 5, and the dominated bacteria were Pseudomonas fragi, P. fluorescens, and Acinetobacter spp. For the VAC lamb, the TVC was 107 CFU/g on Day 9, and the dominated bacteria were lactic acid bacteria, including Carnobacterium divergens, C. maltaromaticum, and Lactococcus piscium. One strain of Pseudomonas spp. also appeared in VAC lamb. The relative abundance of Enterobacteriaceae in VAC lamb was higher than that PT lamb, indicating a more important role of Enterobacteriaceae in spoilage for VAC lamb than that of PT lamb. The microbial compositions changed faster in the lamb stored in a PT than that stored in a VAC, and microbial community compositions of the late storage period were largely different from those of the early storage period for both the conditions. The findings of this study may guide improve the lamb hygiene and prolong the shelf life of the lamb.

Flux‑coupling fault current limiter design for VSC DC grids

Jun Xu,Lei Gao,Guangyang Zhou,Huiyuan Zhang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.1

DC circuit breakers (DCCBs) are used to clear short-circuit faults in several milliseconds. However, short-circuit fault current can reach extreme values. Fault current limiters (FCLs) can present high inductance values during the short-circuit fault period. Thus, they have received considerable attention for reducing the high current breaking requirements of DCCBs. Three types of magnetic flux-coupling solid-state FCLs are designed in this paper, which include mutual inductors and several power electronic switches. In addition, the FCL impedance can be controlled by power electronic switches. By comparing the current limit capacities and structural complexities among the three types of FCLs, a more applicable limiter referred to as a flux-coupling DC current limiter (FCDCCL) can be installed on VSC DC grids. Finally, a simulation model is built in PSCAD/EMTDC based on a ± 10 kV/400 A DC system. The simulation results verify that a significant change in the limiting current can be achieved by the proposed FCDCCL, which can be extended to actual VSC DC grids.

Purification and properties of a milk-clotting enzyme produced by Bacillus amyloliquefaciens D4

Xiaoling He,Bozhong Gan,Fazheng Ren,Huiyuan Guo,Weibing Zhang,Xi Song 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1

The milk-clotting enzyme from Bacillus amyloliquefaciens D4 was purified to 17.2-fold with 20% recovery by precipitation in ammonium sulfate and ion-exchange chromatography. The molecular mass of the enzyme was 58.2kDa as determined by SDS-PAGE, and it was proved to be a metalloprotease by EDTA inhibition. The enzyme was active in the pH range 5.5-7.0 and was inactivated completely by heating at 55℃ for 20 min. The highest level of enzyme activity was obtained at 65 ℃, pH 5.5, in the presence of 25mM CaCl_2. The milk-clotting activity was inhibited only slightly by Na^+ and K^+ and significantly by Cu^(2+), Zn^(2+) and Sn^(2+). The Km value of this enzyme was 0.471 mg/mL. The high level of milk-clotting activity coupled with a low level of thermal stability suggested that the milk-clotting enzyme from B. amyloliquefaciens D4 should be considered as a potential substitute for calf rennet.

Genome-wide identification of microRNAs and phased siRNAs in soybean roots under long-term salt stress

Qian Wang,Yingxia Yang,Guoqing Lu,Xianjun Sun,Youren Feng,Shuangyong Yan,Huiyuan Zhang,Qiyan Jiang,Hui Zhang,Zheng Hu,Rui Chen 한국유전학회 2020 Genes & Genomics Vol.42 No.11

Background Salinity stress, as the key limiting factor for agricultural productivity, can activate a series of molecular responses and alter gene expression in plants. Endogenous regulatory small RNAs, such as microRNAs (miRNAs) and phased siRNAs (phasiRNAs), play crucial roles during stress adaptation and prevent the injury from environmental circumstances. Objective To identify long-term salt stress responsive miRNAs and phasiRNAs as well as their associated genes and pathways in soybean roots. Methods Small RNA and degradome sequencing strategies were applied to genome widely investigate miRNAs and phasiRNAs in soybean roots under control and long-term salt stress conditions. Results In this study, stringent bioinformatic analysis led to the identifcation of 253 conserved and 38 novel miRNA candidates. Results of expression profling, target and endogenous target mimics predictions provided valuable clues to their functional roles. Furthermore, 156 genes were identifed to be capable of generating 21 nt and 24 nt phasiRNAs, in which 37 candidates were confrmed by degradome data for miRNA-directed cleavage. Approximately 90% of these phasiRNA loci were protein coding genes. And GO enrichment analysis pointed to “signal transduction” and “ADP binding” entries and refected the functional roles of identifed phasiRNA genes. Conclusion Taken together, our fndings extended the knowledge of salt responsive miRNAs and phasiRNAs in soybean roots, and provided valuable information for a better understanding of the regulatory events caused by small RNAs underlying plant adaptations to long-term salt stress.

PVA Hydrogel Functionalization via PET-RAFT Grafting with Glycidyl Methacrylate and Immobilization with 2-Hydroxypropyltrimethyl Ammonium Chloride Chitosan via Ring-Open Reaction

Jinsheng Zhou,Yanming Lin,Lin Ye,Ling Wang,Li Zhou,Huiyuan Hu,Qilong Zhang,Hui Yang,Zhongkuan Luo 한국고분자학회 2019 Macromolecular Research Vol.27 No.11

To solve the biofouling problem of polyvinyl alcohol (PVA) hydrogel as the artificial cornea, glycidyl methacrylate (GMA) and 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were grafted on the surface of PVA hydrogel via a new method of photoinduced electron transfer–reversible addition fragmentation chain transfer (PET-RAFT) polymerization and ring-open reaction. Both attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscope (SEM), and thermogravimetric analysis (TGA) confirmed that GMA and HACC were successfully grafted on the surface of PVA hydrogel. A series of experiments to test the hydrophilicity of PVA hydrogel showed that it became hydrophobic due to the introduction of hydrophobic groups after grafting with GMA and HACC. In addition, cytotoxicity in vitro of PVA-g-p(GMA-HACC) hydrogel could be considered as not cytotoxicity according to ISO 10993-5: 2009. The anti-fouling property of hydrogel decreased after grafting with GMA due to the hydrophobic surface, while increased after grafting with HACC due to the steric repulsion of p(GMA-HACC) polymer brush. It’s no doubt that PET-RAFT was a feasible and reliable surface modification method which could be used in many biomolecules due to the excellent advantages.

Quinetides: diverse posttranslational modified peptides of ribonuclease-like storage protein from Panax quinquefolius as markers for differentiating ginseng species

Qiang Zhao,Yunpeng Bai,Dan Liu,Nan Zhao,Huiyuan Gao,Xiaozhe Zhang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.5

Background: Peptides have diverse and important physiological roles in plants and are ideal markers for species identification. It is unclear whether there are specific peptides in Panax quinquefolius L. (PQ). The aims of this study were to identify Quinetides, a series of diverse posttranslational modified native peptides of the ribonuclease-like storage protein (ginseng major protein), from PQ to explore novel peptide markers and develop a new method to distinguish PQ from Panax ginseng. Methods: We used different fragmentation modes in the LTQ Orbitrap analysis to identify the enriched Quinetide targets of PQ, and we discovered Quinetide markers of PQ and P. ginseng using ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis. These “peptide markers” were validated by simultaneously monitoring Rf and F11 as standard ginsenosides. Results: We discovered 100 Quinetides of PQ with various post-translational modifications (PTMs), including a series of glycopeptides, all of which originated from the protein ginseng major protein. We effectively distinguished PQ from P. ginseng using new “peptide markers.” Four unique peptides (Quinetides TP6 and TP7 as markers of PQ and Quinetides TP8 and TP9 as markers of P. ginseng) and their associated glycosylation products were discovered in PQ and P. ginseng. Conclusion: We provide specific information on PQ peptides and propose the clinical application of peptide markers to distinguish PQ from P. ginseng.