2.Surface display of phytase on Saccharomyces cerevisiae for efficient bioethanol production from corn starch.
Yan XIAO ; Xianzhong CHEN ; Wei SHEN ; Haiquan YANG ; You FAN
Chinese Journal of Biotechnology 2015;31(12):1700-1710
Production of bioethanol using starch as raw material has become a very prominent technology. However, phytate in the raw material not only decreases ethanol production efficiency, but also increases phosphorus discharge. In this study, to decrease phytate content in an ethanol fermentationprocess, Saccharomyces cerevisiae was engineered forheterologous expression of phytase on the cell surface. The phy gene encoding phytase gene was fused with the C-terminal-half region of α-agglutinin and then inserted downstream of the secretion signal gene, to produce a yeast surface-display expression vector pMGK-AG-phy, which was then transformed into S. cerevisiae. The recombinant yeast strain, PHY, successfully displayed phytase on the surface of cells producing 6.4 U/g wet cells and its properties were further characterized. The growthrate and ethanol production of the PHY strain were faster than the parent S. cerevisiae strain in the fermentation medium by simultaneous saccharification and fermentation. Moreover, the phytate concentration decreased by 91% in dry vinasse compared to the control. In summary, we constructed recombinant S. cerevisiae strain displaying phytase on the cell surface, which could effectively reduce the content of phytate, improve the utilization value of vinasse and reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate.
6-Phytase
;
metabolism
;
Biofuels
;
Ethanol
;
chemistry
;
Fermentation
;
Industrial Microbiology
;
Saccharomyces cerevisiae
;
metabolism
;
Starch
;
chemistry
;
Zea mays
;
chemistry
3.The expression and significance of human macrophage metalloelastase in both gastric cancer cell lines and gastric cancer tissues
Hong ZHANG ; You-Ming LI ; Chun-Xiao CHEN ;
Chinese Journal of Digestion 1996;0(05):-
Objective To investigate the expression of human macrophage metalloelastase(HME) both in gastric cancer cell lines and gastric cancer tissues,and to find the role of HME in gastric carcino genesis.Methods Fifty eight patients who were operated in our hospital during April to Aug.2003 were enrolled.The samples taken from cancer,paracancer or normal tissues of these patients and cancer cell lines(MGC-803,SGC-7901,AGS)were detected for HME protein and HME mRNA expressions by Western blot and immunohistochemistry,RT-PCR and fluorescence quantitative PCR,respectively. Results Both HME mRNA and HME protein expressions were found in all three gastric cancer cell lines.The expressions of HME mRNA and HME protein in gastric cancer tissues was increased signifi- cantly compared with that in normal tissues(P0.05).Conclusions The increased HME expression in gastric cancer tissures compared with normal tissue indicate that HME may be a potential tumor marker for gastric cancer.
4.Investigations on biological functions of heat shock transcription factor 1 (HSF1) using a gene knock out mouse model
Xianzhong XIAO ; Guangwen CHEN ; Jialu YOU ; J.benjamin IVOR
Chinese Journal of Pathophysiology 2001;17(8):793-
HSF1 is the major heat shock transcription factor that binds heat shock element (HSE) in the promoter of heat shock proteins (HSPs) and controls rapid HSP induction in cells subjected to various stresses such as elevated temperature, chemicals, or exposure to toxins. Although at least four members of the vertebrate HSF have been cloned, details of their individual physiological roles remain relatively obscure. To clarify the exact in vivo functions of HSF1 and assess whether HSF1 exhibits redundant or unique roles, we have created homozygous Hsf1-/- mice using standard gene targeting techniques and isolated Hsf1-/- embryonic fibroblasts. Here we demonstrate that heat shock response (HSR) was not attainable in Hsf1-/- embryonic fibroblasts, and this response was required for thermotolerance and protection against heat-induced apoptosis, and that homozygous Hsf1-/- mice, which survived to adulthood according to genetic background, exhibited multiple phenotypes including: (1) placental defects that reduced embryonic viability after late midgestation (day 13.5); (2) growth retardation; (3) female infertility caused by preimplantation lethality, and (4) increased mortality (+/+ vs -/-, P<0.05) and exaggerated production of proinflammatory cytokine, TNF α (+/- vs -/-, P<0.05) after endotoxin challenge. Interestingly, although Hsf1-/- mice exhibited placental defects and embryonic death, basal HSP expression is not appreciably altered during embryonic development by the HSF1 null mutation, suggesting this factor might be involved in regulating some non-HSP genes or signaling pathways which may be important for development. Taken together, our results established direct causal effects for the HSF1 transactivator in regulating diverse physiological and pathophysiological conditions such as developnent, growth, reproduction, apoptosis and sepsis. The present work also provided a useful mammalian model for further investigating the implications of Hsf1 and its target genes (HSPs and other possible non-HSP genes) in various physiological and pathophysiological processes.
6.Pharmacokinetics of oleanolic acid liposomes in rats
Hongxuan CHEN ; Jiangxiu NIU ; Yanyu XIAO ; Zhipeng CHEN ; Ping HE ; Guoye YOU
Chinese Traditional Patent Medicine 1992;0(04):-
AIM: To study the pharmacokinetics of oleanolic acid liposomes in rats.METHODS: Oleanolic acid liposomes were prepared by ethanol injection-sonication;The pharmaceutical properties including morphology,encapsulation efficiency,particle size,zeta potential were determined.Rats were injected with oleanolic acid lipo-somes and oleanolic acid solution via the tail,respectively.The plasma concentrations of sample in rats were assayed by RP-HPLC.The pharmacokinetic parameters were computered by 3P97 program package.RESULTS: Oleanolic acid liposomes showed almost spherical,the mean diametre was(206.4 ? 4.7) nm.The encapsulation efficiency of oleanolic acid liposomes could be more than 90% based on orthogonal design,and no haemolyticus existed.The plasma concentration-time curves of the oleanolic acid liposomes conformed to a two-compartment model.T1/2? of oleanolic acid liposomes was(33.59 ? 12.53) min,AUC was(240.13 ? 23.62)(?g/mL.min),obviously higher than that of the control preparation.CONCLUSION: The oleanolic acid liposomes with high entrapment efficiency and even size has a good pharmacokinetic parameters by comparison with non-liposomes.
7.Isolation and Identification of Osmotolerant Yeast from "Swollen Can" Soy Sauce
You-Sheng OUYANY ; Xiao-Bao XIE ; Jiao-Di CHEN ; Hua XUE ; Yi-Ben CHEN ;
Microbiology 1992;0(04):-
Three osmotolerant yeasts were isolated from three batches of "swollen can" soy sauce produced by a Guangdong condiment plant. These strains grew faster in the media containing 50%~60% glucose or 15% NaCl than in common yeast media. The three yeasts were identified as Pichia etchellsii by using morphological characteristics, physiological and biochemical tests.
9.Neonatal gigantic rhabdomyoma of the left ventricle: a case report.
Xiao-Fei QIN ; Wan-Hai FU ; Chu-Ming YOU ; Yan-Yu CHEN
Chinese Journal of Contemporary Pediatrics 2009;11(12):1025-1026
Heart Neoplasms
;
pathology
;
Heart Ventricles
;
pathology
;
Humans
;
Infant, Newborn
;
Male
;
Rhabdomyoma
;
pathology
10.Effects of hydrodynamics-mediated RNAi on Mfn2 expression, blood sugar and fat levels in mice.
Chinese Journal of Hepatology 2010;18(10):778-782
OBJECTIVETo investigate the effects of hydrodynamics-mediated RNAi for Mfn2 gene expression in liver and the levels of blood sugar and fat in mice.
METHODSFifty-six male BALB/c mice were randomly divided into normal control group (NC, n = 8), negative control group (HK, n = 24) and transfection group (Mfn2, n = 24) according to random digits table. 1.5 ml plasmid (negative control or Mfn2 shRNA, 75mug for each mouse) diluted into phosphate buffered solution (PBS) was injected into the HK and Mfn2 groups mice via hydrodynamic intravascular injection. Mfn2 mRNA and protein expression in hepatic tissue was detected by RT-PCR and Western-blot 24 hours, 72 hours and 120 hours respectively after injection. At the same time, the levels of fasted blood sugar (FBS) and triglyceride (TG) were measured.
RESULTSCompared with HK mice, the expressions of Mfn2 mRNA (1.00+/-0.03 vs 1.14+/-0.07, t = 4.027, P = 0.007; 1.01+/-0.053 vs 1.18+/-0.07, t = 4.234, P = 0.006) and protein (7.81+/-0.80 vs 8.01+/-0.08, t = 2.941, P = 0.042; 8.05+/-0.15 vs 8.56+/-0.014, t = 4.883, P = 0.039) decreased markedly in Mfn2 mice in 72 and 120 hours after injection. In the fasting state, in 24 hours after injection, FBS in Mfn2 group was significantly lower than that in HK group [(2.65+/-0.70 vs 5.28+/-0.82) mmol/L, t = 6.879, P value less than 0.01] and TG was also significantly higher than that in HK group [(1.96+/-0.32 vs 1.12+/-0.16) mmol/L, t = -6.711, P value less than 0.01]. No statistical differences found between the NC and HK groups for FBS and TG (F = 1.412, P = 0.26; F = 2.711, P = 0.14). The plasma glucose level in Mfn2 mice was significantly higher than that in HK mice [(7.23+/-0.82 vs 5.18+/-0.69) mmol/L, t = 2.050, P value less than 0.01; (7.00+/-0.67 vs 6.05+/-0.76) mmol/L, t = 3.57, P = 0.023] in 72 and 120 hours after injection. However, no differences found between the two groups for blood TG [(1.53+/-0.27 vs 1.37+/-0.18) mmol/L, t = 0.160, P = 0.23; (1.84+/-0.30 vs 1.52+/-0.37) mmol/L, t = 0.330, P = 0.503].
CONCLUSIONThe data indicate that hydrodynamics- mediated RNAi for Mfn2 gene can effectively inhibit the expression of target gene in mice liver in 72 and 120 hours after shRNA administration, and the inhibition of hepatic Mfn2 can induce glycometabolic and fat metabolic disorder.
Animals ; Blood Glucose ; metabolism ; GTP Phosphohydrolases ; genetics ; metabolism ; Gene Expression ; Hydrodynamics ; Lipids ; blood ; Liver ; chemistry ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; RNA Interference ; RNA, Messenger ; genetics