Chinoketides A and B, Two New Antimicrobial Polyketides from the Endophytes of Distylium chinense with the "Black-Box" Co-culture Method

Meng-Meng Lv,Ming-Hui Tan,Li-Wen Lu,Rong-Hua Zhang,Zhi-Yong Guo,Cheng-Xiong Liu,Jin Yang,Kun Zou,Peter Proksch 한국생약학회 2018 Natural Product Sciences Vol.24 No.3

Two new polyketides, chinoketides A and B (1 - 2) with a known compound xylarphthalide A (3), were isolated from the solid medium of the endophytes from the leaves of the relic plant Distylium chinense with the "black-box" co-culture method, and the structures of two new compounds were elucidated by NMR, MS and CD spectra. And the absolute configurations of chinoketides A (1) and B (2) were determined as 2R,3R,8S and 5R,6S by calculating their ECD spectra to compare with the experimental CD spectra. Finally, the antimicrobial activities were evaluated to Erwinia carotovora sub sp. Carotovora (Jones) Bersey et al, and the results showed that compounds 1 - 3 displayed the antimicrobial activities with MIC value at 20.5, 30.4 and 10.2 mg/mL.

Hybrid model- and signal-based chatter detection in the milling process

Meng-Kun Liu,Minh-Quang Tran,Chunhui Chung,Yi-Wen Qui 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1

Chatter causes machining instability and reduces productivity in the metal cutting process. It has negative effects on the surface finish, dimensional accuracy, tool life and machine life. Chatter identification is therefore necessary to control, prevent, or eliminate chatter and to determine the stable machining condition. Previous studies of chatter detection used either model-based or signal-based methods, and each of them has its drawback. Model-based methods use cutting dynamics to develop stability lobe diagram to predict the occurrence of chatter, but the off-line stability estimation couldn’t detect chatter in real time. Signal-based methods apply mostly Fourier analysis to the cutting or vibration signals to identify chatter, but they are heuristic methods and do not consider the cutting dynamics. In this study, the modelbased and signal-based chatter detection methods were thoroughly investigated. As a result, a hybrid model- and signal-based chatter detection method was proposed. By analyzing the residual between the force measurement and the output of the cutting force model, milling chatter could be detected and identified efficiently during the milling process.

RBF Neural Network Controller Research Based on AFSA Algorithm

Qing-kun Song,Meng-meng Xu,Yi Liu 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.3

Molecular cloning and characterization of biphenyl hydrolase-like (BPHL) protein gene from silkworm, Bombyx mori

Kun Gao,Xiang Yuan Deng,Meng Ke Shang,Heying Qian,Xijie Guo 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.3

The cDNA of a biphenyl hydrolase-like (BPHL) protein from Bombyx mori was cloned via rapid amplification of cDNA ends and submitted to GenBank under accession number JN020647. The full-length BmBPHL cDNA was 1161 bp, with four exons and three introns. It consisted of a 208 bp 5′-terminal untranslated region (UTR) and a 191 bp 3′-UTR with three polyadenylation signal sequences AATAAA and a poly(A) tail. The BmBPHL cDNA encodes a 253–amino acid polypeptide with a theoretical isoelectric point of 8.67 and a predicted molecular weight of 28.9 kDa. The deduced amino acid sequence of BmBPHL contained an abhydrolase_6 domain and the Gly-X-Ser-X-Gly motif that is characteristic of serine hydrolases. Sequence comparison showed that BmBPHL is 51% identical to Tribolium castaneum BPHL and 50% identical to Nasonia vitripennis BPHL. Phylogenetic analysis revealed that BmBPHL is grouped with insect BPHL proteins, separating from vertebrate BPHLs. The BmBPHL mRNA transcripts were mainly detected in hemolymph and fat body using fluorescent quantitative real-time PCR. In addition, infectionwith B. mori cytoplasmic polyhedrosis virus (BmCPV) upregulated the relative BmBPHL expression in the hemolymph and midgut. Therefore, BmBPHL may have an important function in the response of silkworms to BmCPV infection.

Influence of Cooling Rate on Secondary Phase Precipitation and Proeutectoid Phase Transformation of Micro-Alloyed Steel Containing Vanadium

Kun Dou,Lingtao Meng,Qing Liu,Bo Liu,Yunhua Huang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.3

During continuous casting process of low carbon micro-alloyed steel containing vanadium, the evolution of strand surface microstructure and the precipitation of secondary phase particles (mainly V(C, N)) are significantly influenced by cooling rate. In this paper, influence of cooling rate on the precipitation behavior of proeutectoid α-ferrite at the γ-austenite grain boundary and in the steel matrix are in situ observed and analyzed through high temperature confocal laser scanning microscopy. The relationship between cooling rate and precipitation of V(C, N) from steel continuous casting bloom surface microstructure is further studied by scanning electron microscopy and electron dispersive spectrometer. Relative results have shown the effect of V(C, N) precipitation on α-ferrite phase transformation is mainly revealed in two aspects: (i) Precipitated V(C, N) particles act as inoculant particles to promote proeutectoid ferrite nucleation. (ii) Local carbon concentration along the γ-austenite grain boundaries is decreased with the precipitation of V(C, N), which in turn promotes α-ferrite precipitation.

Effects of Lactobacillus plantarum SCS2 on blood glucose level in hyperglycemia mice model

Xiao Meng,Yu Qian,Li-Shi Jiang,Jin-Mei Kang,Yan Chen,Juan Wang,Shu-Kun Liu,Zhen-Ming Che,Xin Zhao 한국응용생명화학회 2016 Applied Biological Chemistry (Appl Biol Chem) Vol.59 No.1

In this study, the hyperglycemia mice model was established with 1-week high sugar and fat diet plus with 70 mg/kg body weight of streptozotocin injection for 3 days. Sixty male Kunming mice of 3 weeks old in a specific-pathogen-free grade were divided into six groups randomly, which includes normal group (NG), prevention group (PG), treatment group for low dose (TGL), middle dose (TGM), high dose (TGH), and model group (MG). NG and MG mice were fed with sterile physiological saline (10 mL/kg body weight). PG mice were fed with the concentration of 6.0 × 109 CFU/mL L. plantarum SCS2 suspensions from the second to third week. TGL, TGM, and TGH mice were fed with the concentration of 2.0 × 109, 4.0 × 109, and 6.0 × 109 CFU/mL L. plantarum SCS2 suspensions (10 mL/kg body weight), respectively from fourth to tenth week. The results showed that the fasting and postprandial 2 h blood glucose levels of TGH mice were reduced by L. plantarum SCS2 significantly (p < 0.05) as compared with MG. The body weight of TGH mice came to normal level at tenth week. Content of K+ in plasma of TGH mice was increased and contents of Na+ and Cl− in the plasma of TGH mice were decreased as compared with MG. Meanwhile, content of glycogen in TGH mice was reduced. However, the effect of L. plantarum SCS2 on the prevention of hyperglycemia in PG mice was not significant as compared with NG mice during the experiment. These results suggested that L. plantarum SCS2 showed a hypoglycemic effect on hyperglycemic mice model.

DISCOVERY OF THE IMMUNE RELATED GENES IN RESPONSE TO WHITE SPOT SYNDROME VIRUS INFECTION IN CHINESE SHRIMP Fenneropenaeus chinensis THROUGH MICROARRAY

Xianhong Meng,Jie Kong,Xiaoli Shi,Qingyin Wang,Kun Luo,Sheng Luan,Baoxiang Cao,Ning Liu 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

Growth, Feed Utilization and Blood Metabolic Responses to Different Amylose-amylopectin Ratio Fed Diets in Tilapia (Oreochromis niloticus)

Chen, Meng-Yao,Ye, Ji-Dan,Yang, Wei,Wang, Kun Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.8

A feeding trial was conducted in tilapia to determine the growth performance, nutrient digestibility, digestive enzymes, and postprandial blood metabolites in response to different dietary amylose-amylopectin ratios. Five isonitrogenous and isolipidic diets containing an equal starch level with different amylose-amylopectin ratios of 0.11 (diet 1), 0.24 (diet 2), 0.47 (diet 3), 0.76 (diet 4) and 0.98 (diet 5) were formulated using high-amylose corn starch (as the amylose source) and waxy rice (as the amylopectin source). Each diet was hand-fed to six tanks of 15 fish each, three times a day over a 6-wk period. After the growth trial, a postprandial blood metabolic test was carried out. Fish fed diet 2 exhibited the highest percent weight gain and feed efficiency and protein efficiency ratio, whereas fish fed with diet 5 showed the lowest growth and feed utilization among treatments. The digestibility for starch in fish fed diet 1 and 2 was higher than those in fish fed with other diets (p<0.05). The highest activities for protease, lipase and amylase were found in fish fed the diet 2, diet 1, and diet 1 respectively among dietary treatments, while the lowest values for these indexes were observed in fish fed the diet 3, diet 5 and diet 4, respectively. The liver glycogen concentrations in fish fed diets 4 and 5 were found higher than in fish fed other diets (p<0.05). The feeding rate, hepatosomatic index, condition factor, and plasma parmeters (glucose, triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol) did not differ across treatments. In terms of postprandial blood responses, peak blood glucose and triglycerides were lower after 3 or 6 h in the fish fed with diets 3-5 than in the fish fed diet 1, but delayed peak blood total amino acid time was observed in fish fed with the diets 1 or 2. The lowest peak values for each of the three blood metabolites were observed in fish fed diet 5. The results indicate that high-dietary amylose-amylopectin ratio could compromise growth, but help in reducing the blood glucose stress on fish caused by postprandial starch load.

Luteolin Inhibits Proliferation Induced by IGF-1 Pathway Dependent ERα in Human Breast Cancer MCF-7 Cells

Wang, Li-Meng,Xie, Kun-Peng,Huo, Hong-Nan,Shang, Fei,Zou, Wei,Xie, Ming-Jie Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

The growth of many breast tumors is stimulated by IGF-1, which activates signal transduction pathways inducing cell proliferation. $ER{\alpha}$ is important in this process. The aim of the study was to investigate relationships in vitro among inhibitory effects of luteolin on the growth of MCF-7 cells, IGF-1 pathway and $ER{\alpha}$. Our results showed that luteolin could effectively block IGF-l-stimulated MCF-7 cell proliferation in a dose- and time-dependent manner and block cell cycle progression and induce apoptosis evidenced by the flow cytometric detection of sub-G1DNA content. Luteolin markedly decreased IGF-l-dependent IGF-IR and Akt phosphorylation without affecting Erk1/2 phosphorylation. Further experiments pointed out that $ER{\alpha}$ was directly involved in IGF-l induced cell growth inhibitory effects of luteolin, which significantly decreased $ER{\alpha}$ expression. Knockdown of $ER{\alpha}$ in MCF-7 cells by an $ER{\alpha}$-specific siRNA decreased the IGF-l induced cell growth inhibitory effects of luteolin. $ER{\alpha}$ is thus a possible target of luteolin. These findings indicate that the inhibitory effect of luteolin on the growth of MCF-7 cells is via inhibiting IGF-l mediated PI3K-Akt pathway dependent of $ER{\alpha}$ expression.

miR-638 Serves as a Biomarker of 5-Fluorouracil Sensitivity to Neoadjuvant Chemotherapy in Breast Cancer

Bin Wang,Kun Wang,Jian Yu,Xiao-meng Hao,Yu-lu Liu,Ai-Yan Xing 한국유방암학회 2022 Journal of breast cancer Vol.25 No.3

Purpose: Neoadjuvant chemotherapy (NAC) is widely used to treat breast cancer (BC). The prediction and evaluation of chemotherapy responses remains a significant challenge. Methods: MicroRNAs (miRNAs) play a crucial role in cancer drug resistance. We used a miRNA microarray and identified that miR-638 is downregulated in chemoresistant cases. However, the exact role of miR-638 and the underlying mechanisms of chemoresistance remain unclear. Using real-time quantitative reverse transcription polymerase chain reaction, we found significant downregulation of miR-638 in chemoresistant patients compared with chemosensitive patients. To explore the function of miR-638, we overexpressed and inhibited miR-638 expression in MDA-MB-231 and MCF-7 cells by transfecting them with miR-638 mimics and miR-638 inhibitor, respectively. Cell proliferation and apoptosis were measured using MTS and flow cytometry, respectively. A minimal patient-derived xenograft (MiniPDX™) model was established to evaluate the chemosensitivity to different drugs. Results: The results showed that cell proliferation decreased and cell apoptosis increased in cells transfected with the miR-638 mimic, and cell proliferation and apoptosis were reversed with transfection of miR-638 inhibitor compared with the control group. Among patients who received 5-fluorouracil (5-FU), miR-638 expression levels were lower in the chemoresistant group than in the chemosensitive group. The MiniPDX™ model showed that MDA-MB-231 cells overexpressing miR-638 were more susceptible to 5-FU treatment in vivo. Conclusion: We provided evidence of acquired resistance to 5-FU caused by miR-638 deficiency. Alterations in miR-638 may be used with 5-FU chemotherapy during NAC for BC.