Synthesis of 2-morpholinetetraphenylporphyrins and their photodynamic activities.

A series of 2-morpholinetetraphenylporphyrins functionalized with various substituents (Cl, Me, MeO group) at 4-phenyl position were prepared via nucleophilic substitution of 2-nitroporphyrin copper derivatives with morpholine by refluxing under a nitrogen atmosphere and then demetalization. Their basic photophysical properties, intracellular localization, cytotoxicities in vitro and in vivo were also investigated. All synthesized photosensitizers exhibited longer maxima absorption wavelengths than Hematoporphyrin monomethyl ether (HMME). They showed low dark cytotoxicity compared with that of HMME and were more phototoxic than HMME against Eca-109 cells in vitro. M3 also exhibited better photodynamic antitumor efficacy on BALB/c nude mice at a lower concentration. Therefore, M3 is a promising antitumor photosensitizer in photodynamic therapy application.

Inhibition of Laser-Induced Choroidal Neovascularization by Hematoporphyrin Dimethylether-Mediated Photodynamic Therapy in Rats.

This study aimed to investigate the effect of hematoporphyrin dimethylether (HDME)-mediated photodynamic therapy for laser-induced choroidal neovascularization (CNV) in adult Brown Norway rats. HDME was administered via tail vein at 14 d after the laser photocoagulation, and the rats received irradiance with a laser light at 570 nm at 15 min after injection. CNV was evaluated by fundus photography, fundus fluorescein angiography, optical coherence tomography, and hematoxylin and eosin staining. We found that CNV was occurred at 7 d after photocoagulation and reaching peak activity at 14 d after photocoagulation. There is a significant reduction in the total area of the fluorescein leakage and the number of strong fluorescein leakage spots on 7 d after HDME-mediated photodynamic therapy (PDT). The results suggest that HDME-mediated PDT inhibits laser-induced CNV in rats, representing a promising therapy for wet age-related macular degeneration.

Characteristics and influencing factors of economic resilience in industrial parks.

Economic resilience has been a popular issue in recent years. Along with the consideration of severe shocks caused by the financial crisis of 2007-2008 and globalization of industry and the upgradation of knowledge and technology, economic resilience has brought in much attention. About 50 years of development of planned industrial parks in Taiwan has resulted in considerable economic scale; however, due to changes in interior demands and the exterior environment with time, rearrangement and industrial transformation have made the development of industrial parks difficult. Accordingly, the resilience of planned industrial parks in Taiwan, when encountering a variety of shocks, need to be reviewed and examined. This study selects 12 planned industrial parks from Tainan and Kaohsiung, in southern Taiwan, as subjects and had a complete understanding of economic resilience and factors that influence economic resilience from literature reviews. Four quadrant model constituted by the indicators of economic resistance and recovery as well as discriminant analysis are implemented to analyze the resilience of industrial parks with different backgrounds and various shocks, as well as the elements influencing the resilience. Analytical results indicate that planned industrial parks with industrial structures based on specialized variety or with a steady input of knowledge and innovation to research and development benefited the industrial parks in better resilience, while complete infrastructure planning and governance are fundamental conditions for resilience.

Synthesis and structure-activity correlation of natural-product inspired cyclodepsipeptides stabilizing F-actin.

The fundamental role played by actin in the regulation of eukaryotic cell maintenance and motility renders it a primary target for small-molecule intervention. In this arena, a class of potent cytotoxic cyclodepsipeptide natural products has emerged over the last quarter-century to stimulate the fields of biology and chemistry with their unique actin-stabilizing properties and complex peptide-polyketide hybrid structures. Despite considerable research effort, a structural basis for the activity of these secondary metabolites remains elusive, not least for the lack of high-resolution structural data and a reliable synthetic route to diverse compound libraries. In response to this, an efficient solid-phase approach has been developed and successfully applied to the total synthesis of jasplakinolide and chondramide C and diverse analogues. The key macrocylization step was realized using ruthenium-catalyzed ring-closing metathesis (RCM) that in the course of a library synthesis produced discernible trends in metathesis reactivity and E/Z-selectivity. After optimization, the RCM step could be operated under mild conditions, a result that promises to facilitate the synthesis of more extensive analogue libraries for structure-function studies. The growth inhibitory effects of the synthesized compounds were quantified and structure-activity correlations established which appear to be in good alignment with relevant biological data from natural products. In this way a number of potent unnatural and simplified analogues have been found. Furthermore, potentially important stereochemical and structural components of a common pharmacophore have been identified and rationalized using molecular modeling. These data will guide in-depth mode-of-action studies, especially into the relationship between the cytotoxicity of these compounds and their actin-perturbing properties, and should inform the future design of simplified and functionalized actin stabilizers as well.

Solid-phase based total synthesis of Jasplakinolide by ring-closing metathesis.

The study of classical ring-closing metathesis and relay ring-closing metathesis in a total synthesis of Jasplakinolide and its desbromo analog is described.

Solid-phase based synthesis of jasplakinolide analogs by intramolecular azide-alkyne cycloadditions.

The synthesis of a focused library of jasplakinolide analogs with a 1,2,3-triazole in place of an E-configured double bond is described, featuring the Cu(I) catalyzed azide-alkyne cycloaddition reaction as an efficient macrocyclization tool.

Preparation of a chlorophyll derivative and investigation of its photodynamic activities against cholangiocarcinoma.

Photodynamic therapy (PDT) is emerging as a promising method for the treatment of various cancer diseases. However, the clinical application of PDT is limited due to the lack of effective photosensitizers. In this study, a novel chlorophyll derivative, N,N-bis(2-carboxyethyl)pyropheophorbide a (BPPA), had been synthesized and characterized. BPPA had a characteristic long wavelength absorption peak at 669nm and a singlet oxygen quantum yield of 0.54. To investigate the photodynamic ability of BPPA against cholangiocarcinoma (CCA), cellular uptake, subcellular location and bio-distribution, in vitro and in vivo PDT efficacy of BPPA were studied. The results showed that BPPA could rapidly accumulate in QBC-939 cells and localize in the cytoplasm. BPPA- PDT was effective in reducing the cell viability in a drug dose- and light dose-dependent manner in vitro. In CCA xenograft nude mouse model, the concentration of BPPA in the plasma lowered rapidly, and the fluorescence signal peaked at 0.5h and 2h after injection in the skin and tumor, respectively. Significant quantities could be observed in the tumor. BPPA followed by irradiation could significantly inhibit growth of tumors, and histological examination revealed necrotic damage in PDT-treated tumors. These results suggested that BPPA could be a promising drug candidate for photodynamic therapy in cholangiocarcinoma.

Tetraphenylporphyrin derivatives possessing piperidine group as potential agents for photodynamic therapy.

Photodynamic therapy (PDT) is a noninvasive therapeutic and promising procedure in cancer treatment and has attracted considerable attention in recent years. In the present paper, 2-piperidinetetraphenylporphyrin derivatives (P1-P3) conjugated with different substituents (Cl, Me, MeO group) at phenyl position were synthesized via nucleophilic substitution of 2-nitroporphyrin copper derivatives with piperidine by refluxing under a nitrogen atmosphere and then demetalization. The combination of 1H NMR, 13C NMR and HR-MS was used to elucidate the identities of them. Their photophysical and photochemical properties, intracellular localization, cytotoxicity in vitro and in vivo against QBC-939 cells were investigated. They have absorption at wavelength about 650nm. All synthesized photosensitizers showed low dark cytotoxicity and comparable with that of hematoporphyrin monomethyl ether (HMME). And they were more phototoxic than HMME to QBC-939 cells in vitro. In bearing QBC-939 tumor BALB/c nude mice, when it treated with 5mg/kg dose of PS and laser light (650nm, 100J/cm2, 180mW/cm2), the growth of tumor was inhibited compared to the control group. Among them, P3 exhibited better photodynamic antitumor efficacy on BALB/c nude mice at lower concentration. These results indicate that P3 is a new potential antitumor photosensitizer in photodynamic therapy and deserves further investigation.

Synthesis of spiroketal enol ethers related to tonghaosu and their insecticidal activities.

This paper describes the syntheses and biological activities of a number of spiroketal enol ethers which are analogues of the plant extract tonghaosu. The insecticidal potential of this spiroketal system is assessed.

Synthesis and antifeeding activities of Tonghaosu analogues.

Tonghaosu (1), a lead for a botanical antifeedant, and its 22 analogues were synthesized according to a previously reported concise and straightforward procedure. The structures of all new compounds were confirmed by NMR, IR, MS, and HREIMS or elemental analysis. Their insect antifeedant activities against the large white butterfly (Pieris brassicae L.) were examined, and six analogues (Z- and E-6h and Z-isomers of 6i-l), which contain 1,3-diyn or 3,4-methylenedioxyphenyl acetylene group, showed considerable antifeedant activity. Interestingly, Z-isomers of 6i-k are much more active than their corresponding E-isomers.

The Application of a Novel Lytic System to the Recovery of Recombinant Proteins in E.coli.

In order to efficiently recover recombinant proteins, a temperature-sensitive lytic system was constructed on the basis of the feature that T4 lysozyme disrupts the bacteria through cutting specific bond in the peptidoglycan layer of cell wall. This system was evaluated by constructing and introducing a low copy plasmid pSC-lys (pSC101 replication origin) into E.coli. The plasmid contained a temperature sensitive T4 lysozyme (LYS(ts)) gene under the control of three tandem tac promoters and the LacI repressor, which is compatible with other plasmids carrying pMB1, ColE1 replication origins, etc. Under the optimum lysis conditions, 2--5 fold condensed cultures resuspended in buffer A, beta-galactosidase, recombinant chaperone GroEL and ZZ-fusion salmon hexamic calcitonin (Cal6) in E.coli were released simply, rapidly, and quantitatively, as co-expressed with LYS(ts). The two tested recombinant proteins maintained their significant productions. Instead of other cumbersome lysising methods, this novel lytic system will be useful in recovery of recombinant proteins for further purification in the field of biotechnology.

Increase in Hydrophobicity of Signal Peptide Enhances Secretion of Penicillin G Acylase.

An artificial strong hydrophobic signal peptide (ASP), containing ten leucines in tandem in the hydrophobic core, was utilized to replace the wild type signal peptide (WTSP) of penicillin G acylase (PAC), by the fusion to its 4 pro site. PAC expression plasmids, including pKKpacdeltaSP, pKKpacWTSP, pKKpacASP, pETpacWTSP and pETpacASP, were constructed. The length and the amino- and carboxyl-terminus amino acid composition of ASP and WTSP were kept identical. The activity assay and Western-blotting analysis were used to study the effect of ASP and WTSP on the secretion of PAC in tac, T7 and dissolved-oxygen regulation expression systems, respectively. Lack of signal peptide in pKKpacdeltaSP resulted in the accumulation of 91 kD PAC precursor (without signal peptide, but with the space peptide between alpha-subunit and beta-subunit) in the cytosol, indicating that the secretion of PAC depends on the signal peptide. In BL21(pKKpacASP) cells, the PAC activity and proprecursor (with signal peptide and space peptide) processing capacity were increased by about 54% and 38.5%, respectively, in comparison with BL21(pKKpacWTSP) cells. Compared with BL21(DE3) (pETpacWTSP), however, the PAC activity and proprecursor processing capacity in BL21(DE3) (pETpacASP) were enhanced by about 69% and 43.5%, respectively. The PAC activity expressed from pETpacASP was about 67% more than that from pETpacWTSP in the dissolved-oxygen-regulated expression system GJ100. Resulting from the strong hydrophobicity of ASP, therefore, the PAC activity and proprecursor processing capacity were increased by about 63% and 41% on average, respectively, in comparison with WTSP. In conclusion, the increase in hydrophobicity of the signal peptide hydrophobic core enhanced the secretion of penicillin G acylase.

Molecular Cloning and Expression of a New A Chain of beta-Bungarotoxin.

The cDNA encoding a new A chain of beta-bungarotoxin was cloned from Bungarus multicinctus. It encoded a 27-amino acid signal peptide and a mature protein of 120 amino acids. The mature protein had the same 13 cysteines as the other A chains and shared high homology with them. The cDNA encoding the PLA(2) from Naja naja atra was also cloned by the use of the same degenerate primers. The cDNAs encoding the new A chain and the PLA(2) were highly expressed in E. coli as soluble fusion proteins and purified by affinity chromatography. The two recombinant proteins achieved after digestion by X(a) factor showed weak and strong PLA(2) activity, respectively.

Stereoselective synthesis of (+)-boronolide and its 8-epimer.

Starting from readily available carbohydrates the synthesis of 8-epi-(+)-boronolide 19 and (+)-boronolide was achieved with diastereoselective propargylation of alpha-oxygenated aldehyde as a key step.

Straightforward synthesis of two pairs of enantiomeric butenolides 3-tetradecyl- and 3-hexadecyl-5-methyl-2(5H)-furanone.

Based on the synthetic method of optically active 3-alkyl-5-methyl-2(5H)-furanones from lactic acid, two pairs of chiral butenolides 3-tetradecyl- and 3-hexadecyl-5-methyl-2(5H)-furanone have been straightforwardly synthesized from methyl stearate and methyl palmitate respectively by aldol condensation with (R)- or (S)-O-tetrahydropyranyl lactal prepared from corresponding ethyl lactate and beta-elimination.