Aim To investigate the anticancer effect of a new xanthono-pyridine derivative N, N '-( 7-oxo-7H-chromeno[3,2-h] quinoline-5,9-diyl)-bis(2-( pyrroli-din-1-yl)acetamide) (XP-16) on human lung carcino-ma cell line A549 and the potential mechanism. Meth-ods Antiproliferative effect of XP-16 on A549 cells was evaluated by MTT assay, morphological examina-tion and colonial assay. Apoptosis detection was car-ried out using Hoechst 33258 and PI double-dyeing method. Intracellular Ca2+ concentration ( [ Ca2+] i ) and mitochondria membrane potential were detected by fluorospectrophotometer. A549 cells treated with XP-16 were collected for Bad and metallothionein 1 A ( MT-1 A ) transcript analysis by real-time reverse tran-scriptase-polymerase chain reaction ( qRT-PCR) . Re-sults XP-16 inhibited A549 cell proliferation in dose-and time-dependent manner. Typical apoptotic mor-
phology such as chromatin aggregation and nuclear fragmentation was observed in A549 cells treated with XP-16 for 24 h, and the apoptosis was showed in a dose-dependent manner. After treated with XP-16, [ Ca2+] i and mitochondria membrane potential of A549 cells were decreased, and relative mRNA level of Bad and MT-1A was up-regulated. Conclusions XP-16 has anticancer effect on A549 cells through apoptosis, which might be associated with decreasing intracellular Ca2+ concentration and mitochondria membrane poten-tial. Up-regulation of MT-1A expression might be the result of decreased [ Ca2+] i .

Objective To explore the clinical application value and feasibility of contrast-enhanced ultrasonography (CEUS) in rapid diagnosis for bleeding of hepatocellular carcinoma. Methods From January 2009 to December 2012, 58 patients from the 302nd Hospital of the People′s Liberation Army underwent CEUS and conventional ultrasound, who were suspicioused primary bleeding of liver cancer or secondary bleeding of liver cancer after percutaneous radiofrequency ablation (RFA). The change of effusion volume in front of liver and in abdominal cavity, the perfusion time, range and characteristics of contrast agent, tumor vessel and the characteristic manifestation of active bleeding within the tumor and subcapsular were evaluated. Theχ2 test was used to compare the show rates of lesion boundary and the bleeding point by conventional ultrasound and CEUS. The t test was used to compare the change of effusion in front of liver and in abdominal cavity from 0 min to 30 min after bleeding were diagnosis by CEUS. Results For 58 cases of suspicious rupture and bleeding of liver cancer, 34 cases were conifrmed by clinical and imaging ifndings. The bleeding points were detected by conventional ultrasound in 5 cases. The bleeding points in 30 cases (including 4 cases of rapid bleeding, 7 cases of medium bleeding and 19 cases of slow bleeding) were detected by CEUS. The detection rate of lesion boundary, tumor vessel and bleeding point of CEUS were higher than those of conventional ultrasound, and the differences were statistically significant (χ2=10.350, P=0.001; χ2=4.300, P=0.034;χ2=36.790, P=0.0007). CEUS showed that contrast agent continuously concentrated at the bleeding point of lesions, and different degrees of bleeding were shown as′jet-like′,′linear′or′intermittent′spillover. The volume of effusion in front of the liver and in abdominal cavity at 30 min was more than those at 0 min after bleeding were diagnosis by CEUS, and the differences were statistically significant (the volume of effusion in abdominal cavity:t=-3.467, P=0.026;t=-12.895, P=0.000;t=-3.055, P=0.007;the volume of effusion in front of the liver:t=-8.110, P=0.001;t=-5.642, P=0.002;t=-5.981, P=0.000). Conclusions CEUS can show direct signs of rupture and bleeding of liver cancer, and the degree of bleeding can be evaluated according to the extravasation characteristics of contrast medium and the changes of lfuid volume. Therefore, CEUS can provid an objective basis for rapid diagnosis of ruptured hepatocellular carcinoma in the emergency scene and bedside.

Rhizopus oryzae lipase (ROL) is not only a biocatalyst used in a broad range of biotechnological fields, but also a model to investigate the function of intramolecular chaperone in the post-translational processing of lipase. In this study, we cloned and expressed the mature lipase gene (m-ROL) containing the pre-sequence (pro-ROL) of R. oryzae HU3005 in Pichia pastoris GS115 and characterized their enzymatic activities. m-ROL exhibited higher hydrolysis activity towards middle-chain substrates (C10 and C12) at pH 9.0, whereas pro-ROL preferred short-chain substrates (C4) and displayed maximal activity at pH 8.0. Moreover, pro-ROL possessed better thermal stability than m-ROL. This enzymatic discrepancy between m-ROL and p-ROL may be due to the pre-sequence that affects the folding and conformation of the mature lipase domain. To improve the expression level of m-ROL in P. pastoris, overlap extension PCR was conducted to substitute eight less-frequently used codons of m-ROL with frequently used codons. After methanol-induced expression for 72 h, the activity and protein content of the codon optimized m-ROL reached 132.7 U/mL and 50.4 mg/L, while the activity of the parental m-ROL and pro-ROL are 28.7 U/mL and 14.4 mg/L, 29.6 U/mL and 14.1 mg/L, respectively.
Codon ; Enzyme Precursors ; biosynthesis ; chemistry ; genetics ; Enzyme Stability ; Lipase ; biosynthesis ; genetics ; metabolism ; Pichia ; enzymology ; genetics ; Protein Engineering ; methods ; Protein Folding ; Recombinant Proteins ; biosynthesis ; genetics ; Rhizopus ; enzymology ; genetics ; Substrate Specificity

Aspergillus niger lipases are important biocatalysis widely used in industries for food processing and pharmaceutical preparation. High-level expression recombinants can lead to cost effective lipase large scale production. Full length gene synthesis is an efficient measure to enhance the expression level of the gene. In order to reduce the non-specific binding between oligonucleotides and bases mutation caused by the complicate secondary structure of DNA and excessive PCR amplification, a frequently phenomenon in one-step gene synthesis, we used a two-step method including assembly PCR (A-PCR) and digestion-ligation step to synthesis Aspergillus niger lipase gene lipA. Assisted by DNA2.0 and Gene2Oliga software, we optimized the codon usage and secondary structure of RNA and induced enzyme sites Cla I (237 site) and Pst I (475 site) into the gene. In the first step, fragments F1 (237 bp), F2 (238 bp) and F3 (422 bp) were separately synthesized by assembly PCR. In the second step, fragments F1, F2 and F3 were separately digested by Cla I and Pst I, and then ligated into a full length lipA gene. Two-step method efficiently enhanced successful ratio for full-length gene synthesis and dispersed the risk for gene redesign. The synthesized gene was cloned into pPIC9K vector and transferred into Pichia pastoris. After methanol inducement, the expression level of the codon optimized lipA-syn gene reached 176.0 U/mL, 10.8-fold of the original lipA gene (16.3 U/mL) in Pichia pastoris GS1115. The recombinant offers the possibility for lipase large-scale production.
Base Sequence ; Carboxylic Ester Hydrolases ; biosynthesis ; genetics ; Cloning, Molecular ; Genes, Synthetic ; Genetic Engineering ; methods ; Genetic Vectors ; genetics ; Molecular Sequence Data ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

Random mutagenesis on Bacillus pumilus lipase YZ02 gene was conducted by using error-prone PCR strategy. Through two cycles of directed evolution, two optimum mutants BpL1-7 and BpL2-1369 with lipase activity improved 2 folds and 6 folds respectively were screened. The sequence of BpL2-1369 lipase gene showed that four nucleotides substitution, T61C, C147T, A334G and T371A have occurred, and three of them caused amino acid changes. Thus, amine acid Ser21 was changed into Pro21, Arg112 to Gly112, and Leu124 to His124. According to the 3D structure of Bacillus pumilus lipase mimicked by SWISS-MODEL Repository, three mutated amino acids were located at the third amino acid of the first alpha-helix, the turn between the fourth and fifth beta fold, and the first amino acid of the fifth beta fold, respectively. The BpL and BpL2-1369 genes were ligated into pET28a vector, and transferred into E. coli BL21 (DE3). After induced by IPTG the lipases were purified and characterized. The results showed that the specific activity of the evolved lipase was 1.31-fold than that of the wild lipase, and the Km decreased from 8.24 mmol/L to 7.17 mmol/L. The pH stability of the evolved lipase was better than wild lipase when pH>8.0.
Bacillus ; enzymology ; genetics ; Directed Molecular Evolution ; Lipase ; chemistry ; genetics ; metabolism ; Point Mutation ; Polymerase Chain Reaction ; methods ; Protein Engineering ; Sequence Analysis, Protein

In order to realize over-expression of Burkholderia cepacia (B. cepacia) lipase, we introduced the widely used T7 RAN polymerase expression system into B. cepacia G63 to over-express the lipase gene. By using PCR technique, we amplified the T7 RNA polymerase gene (T7 RNAP) from the BL21 (DE3) and cloned it into the suicide plasmid pJQ200SK. After that, we flanked T7 RNAP with two 500 bp homologous fragments and integrated it into the genomes of B. cepacia by tri-parental mating, so that T7 RNAP was under-controlled by lipase gene (lipA) promoter. Then, we cloned the lipA and its partner gene lipB into the vector pUCPCM and pBBR22b both or separately. Therefore, we got 7 expression plasmids pBBR22blipAB, pBBR22blipA, pUCPCMlipAB, pUCPCMlipA, pUCPCMdeltalipAlipB, pUCPCMdeltalipA, pUCPCMdeltalipB, and then electroporated them into B. cepacia containing T7 RNA. After shake flask culture, we found B. cepacia containing pUCPCMlipAB produced the most quantity of lipase, and lipase activity was up to 607.2 U/mg, 2.8-folds higher than that of the wild strain. Moreover, lipase activities of all engineering strains except the one containing pUCPCMdeltalipB were enhanced to some extent. The specific activities of wild type B. cepacia and B. cepacia containing pUCPCMlipAB were respectively 29 984 U/mg and 30 875 U/mg after ammonium sulfate precipitation and gel filtration chromatography. The T7 RNA polymerase expression system could effectively enhanced lipase expression in B. cepacia, and secretion signal PelB and ribosome-binding site may promote lipase expression in engineering strain.
Bacteriophage T7 ; genetics ; Burkholderia cepacia ; enzymology ; genetics ; Cloning, Molecular ; DNA-Directed RNA Polymerases ; genetics ; Escherichia coli ; enzymology ; genetics ; Lipase ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Transformation, Genetic ; Viral Proteins ; genetics