Shinya Kodani

Antibacterial discovery in actinomycetes strains with mutations in RNA polymerase or ribosomal protein S12.

We show that selection of drug-resistant bacterial mutants allows the discovery of antibacterial compounds. Mutant strains of a soil-isolated Streptomyces species that does not produce antibacterials synthesize a previously unknown class of antibacterial, which we name piperidamycin. Overall, 6% of non-Streptomyces actinomycetes species and 43% of Streptomyces species that do not produce antibacterials are activated to produce them. The antibacterial-producing mutants all carried mutations in RNA polymerase and/or the ribosomal protein S12.

An endoplasmic reticulum (ER) stress-suppressive compound and its analogues from the mushroom Hericium erinaceum.

Three new compounds, 3-hydroxyhericenone F (1), hericenone I (2), and hericenone J (3), were isolated from the mushroom Hericium erinaceum. The structures of 1-3 were determined by the interpretation of spectral data. Compound 1 showed the protective activity against endoplasmic reticulum (ER) stress-dependent Neuro2a cell death, however, compounds 2 and 3 did not.

Endoplasmic Reticulum (ER) Stress-Suppressive Compounds from Scrap Cultivation Beds of the Mushroom Hericium erinaceum

Four compounds were isolated from scrap cultivation beds of the mushroom, Hericium erinaceum. Compounds 1–4 were identified as methyl 4-hydroxy-3-(3-methylbutanoyl) benzoate, 2-chloro-1,3-dimethoxy-5-methylbenzene, methyl 4-chloro-3,5-dimethoxybenzoate, and 4-chloro-3,5-dimethoxybenzaldehyde by an interpretation of the NMR and MS data, respectively. This is the first reported isolation of 1 from a natural source. All the compounds showed protective activity against endoplasmic reticulum stress-dependent cell death.

Isolation and structure determination of new siderophore tsukubachelin B from Streptomyces sp. TM-74

The new siderophore tsukubachelin B (1) was isolated from the iron-deficient culture medium of the newly isolated strain Streptomyces sp. TM-74. The chemical structure of tsukubachelin B (1) was established via interpretation of 2D nuclear magnetic resonance and electrospray ionization-mass spectroscopic data. The structure of tsukubachelin B (1) comprises 6 mol of amino acids, including 2 mol of serine and 1 mol each of ornithine, N-α-methyl-N-δ-hydroxy-N-δ-formylornithine, N-α-methyl-N-δ-hydroxyornithine, and cyclic N-hydroxyornithine.

New Sesquiterpenoid from the Mushroom Sparassis crispa

A new sesquiterpenoid (1) was isolated from the mushroom, Sparassis crispa, along with a known sesquiterpenoid (2). The structure of 1 was determined as (3R *, 3aS *, 4S *, 8aR *)-3-(1′-hydroxy-1′-methylethyl)-5,8a-dimethyldecahydroazulen-4-ol by the combination of NMR and ESI-MS analyses.

Structure determination of a siderophore peucechelin from Streptomyces peucetius

Previously, Park et al. isolated a new siderophore from Streptomyces peucetius ATCC 27952 based on information of the genome sequence and the structure of the siderophore was deduced to be a cyclic peptide based on MS/MS analysis. To clarify the structure of the siderophore, we cultured S. peucetius with iron deficient medium. Through several chromatographic procedures, the siderophore named peucechelin was isolated with the yield enough to perform NMR experiments. The planar structure of peucechelin was elucidated by the combination of ESI-MS experiment and NMR spectroscopic analyses of the gallium (III) complex. Unlike the previously deduced cyclic structure, the structure was determined to be a linear peptide which was similar to a known siderophore foroxymithine. The stereochemistries of amino acids constituting peucechelin were determined by applying modified Marfey method to the hydrolysate. Since the biosynthetic gene of peucechelin was formerly determined by Park et al. the similar genes were searched using genome data of other streptomycetes. As a result, the similar genes were found in the genome data of S. venezuelae and S. purpureus. Isolation and identification of siderophore was performed from the iron deficient culture of S. venezuelae. The siderophore of S. venezuelae was identified to be known compound foroxymithine by analysis ESI-MS and NMR spectra in the similar manner with peucechelin. Production of foroxymithine was also observed in the iron deficient culture of S. purpureus. Based on the genome data, comparison of the biosynthetic genes of structurally related siderophores peucechelin and foroxymithine was accomplished in discussion.

Montiporic acid D, a new polyacetylene carboxylic acid from scleractinian coralMontipora digitata

A new polyacetylene carboxylic acid named montiporic acid D (1) was isolated along with a known polyacetylene alcohol, (Z)-13,15-hexadecadien-2,4-diyn-1-ol (2) from scleractinian coral Montipora digitata. The structures of compounds were determined by analyses of NMR and MS spectra.

Isolation and structural determination of a new macrolide, makinolide, from the newly isolated Streptomyces sp. MK-30

Isolation and structural determination of a new macrolide, makinolide, from the newly isolated Streptomyces sp. MK-30

Mechanism of peptide modification by low-temperature microwave plasma

The possibility of changing the biological function of peptides was investigated using low pressure microwave plasma, aiming to develop a new and efficient technique to inactivate biohazardous proteinaceous molecules such as abnormal prions and figure out the insights of the interactions between non-reactive plasmas and peptide molecules. In the present research, a peptide, Arginine Vasotocin, having an inherent bio-function of controlling the water penetrability through amphibian abdominal skin was used. The interaction with low temperature plasma is investigated. The mechanisms involved in the modifications produced by argon plasma exposure are discussed, according to the obtained results of X-ray photoelectron spectroscopy, mass spectrometry, nuclear magnetic resonance, and water penetrability tests. The loss of water enhancement property of the peptide molecules after argon plasma treatment is explained.

Isolation of a new antibacterial peptide achromosin from Streptomyces achromogenes subsp. achromogenes based on genome mining

Isolation of a new antibacterial peptide achromosin from Streptomyces achromogenes subsp. achromogenes based on genome mining