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Methylotrophic yeast is a useful host for producing heterologous proteins using the unique and strong alcohol oxidase 1 (AOX1) promoter, which is induced by methanol and repressed by various carbon sources. However, methanol is preferably avoided in industrial-scale fermentation given its toxicity, flammability, and explosiveness. To develop a protein production system under reduced methanol supply conditions, we attempted to characterize the AOX1 promoter induction activity by comparing derepression conditions with methanol induction conditions. This comparison is important because decreasing methanol consumption would enhance the industrial value of Ogataea minuta for heterologous protein production. For such a comparison, an alcohol oxidase-deficient (Δaox) strain was generated, with methanol only being used for AOX1 promoter induction. We also developed a culture process in a jar fermentor using the O. minuta Δaox strain under mixed feed conditions to achieve heterologous protein production comparable to that of the wild-type strain under low-methanol conditions. [ABSTRACT FROM AUTHOR]

Citrinadin A is a pentacyclic indolinone alkaloid isolated from the cultured broth of a fungus, Penicillium citrinum, which is separated from a marine red algae. The absolute stereochemistry of the pentacyclic core citrinadin A and its new congener, citrinadin B, is elucidated by analysis of the ROESY spectrum for the chlorohydrin derivative of citrinadin B as well as comparison of the electronic circular dichroism (ECD) spectra for citrindin B and citrindin A with those of known spirooxiindole alkaloids.

Research has been conducted on the macrolides amphidinolides. The isolation of these amphidinolides from the marine dinoflagellate Amphidinium sp. has been carried out and the results indicate that the presence of allyl epoxide and the ketone at C-20 is important for the amphidinolides' cytotoxicity.

Research has been conducted on the cytotoxic macrolide amphidinolide E from a marine dinoflagellate. The absolute configurations of this macrolide have been determined at different chiral centers via chemical means and NMR data.

Research has been conducted on the cytotoxic macrolide amphidinolide W, isolated from dinoflagellate Amphidinium sp. The structure of this macrolide has been investigated and the results indicate that amphidinolide W is the only macrolide without the exomethylene unit.

Results indicate that amphidinolide T1 is generated from four polyketide chains derived from an isolated C(sub)1 unit from C-2 of acetates and three C(sub)2 units from C-2 of acetates. Data show that T2, T3, and T4 amphidinolide macrolides are structurally related to T1.

The isolation and structure of an unique macrolide, amphidinolide T, along with the stereochemistry and absolute configurations, with respect to specific carbon positions, are described.

Research was conducted to examine the isolation and structure elucidation of the novel polyhydroxyl metabolite colopsinol A from marine dinoflagellate Amphidinium sp. 2D NMR experiments such as CH2-selected editing HSQC and FABMS/MS data were used as the basis of extensive spectroscopic analyses. Results demonstrate that the polyketide aglycon contained a C56-linear aliphatic chain with one exo-methylene and two methyl branches, two ketones, two epoxide rings, five hydroxyl groups and a tetrahydropyran.

A study was conducted to describe the isolation of nakadomarin A, a new manzamine-related alkaloid supporting an 8/5/5/5/15/6 ring system, from the marine sponge Amphimedon sp. The alkaloid was extracted from the sponge with MeOH. It featured a furan ring that was elucidated based on spectroscopic data. The alkaloid's stereochemistry was determined from proton couplings and from a biogenetic path through ircinal A.

Dinoflagellate Amphidinium sp. contains a 27-membered macrolide, which comprises the hemiketal ring called amphidinolide L. KB human epidermoid carcinoma cells and L1210 murine leukemia cells are sensitive to the cytotoxic effects of amphidinolide L. Dinoflagellate Amphidinium sp. is an integral component of Okinawan flatworm Amphiscolops breviviridis.

The Okinawan marine sponge Luffariella sp. yields five new sesterterpenes, luffariolides A-E, along with the known (6E)- and (6Z)-neomanoalides. Spectroscopic studies reveal the structures of the new terpenes. Luffariolide A is an optically inactive structural cousin of (6E)-neomanoalide with an alpha, beta-unsaturated ester. Luffariolide B is a regioisomer of (6Z)-neomanoalide and has an R configuration at C-4. Luffariolide C is 2, 3-dihydro-(6Z)-neomanoalide with a 3R,4R configuration. Luffariolides D and E are neomanoalide analogues with alpha, beta-unsaturated delta- and gamma- lactones. All the sponge extracts exhibit cyctotoxicity against murine lymphoma L1210 cells in lab bioassays.

The transition behavior from a Ti-Cu alloy to nanoporous α-Ti, the kinetics of the dealloying reaction, and the coarsening of nanoporous α-Ti were studied, and the mechanism of dealloying with a metallic melt was investigated. When a Ti50Cu50 alloy disk was immersed in a Mg melt, the Cu content decreased from the surface of the disk, and transition layers of α-Ti and Ti2Cu were formed. The growth of the transition layers followed a parabolic law and the activation energy was close to those reported for the diffusion of solute atoms in liquids, suggesting that diffusion of Cu in the Mg melt mainly contributed to the rate-controlling process for the dealloying reaction. The temperature and time dependences of the ligament size followed a power law with an exponent of 4, suggesting that surface diffusion plays an important role in coarsening. All of these results are consistent with those reported for dealloying in aqueous solution, indicating that the underlying dealloying mechanism in a metallic melt is similar to that in aqueous solution. [ABSTRACT FROM AUTHOR]