Kyoko Adachi

Two cyclic peptides, anabaenopeptins, a third group of bioactive compounds from the cyanobacteriumAnabaena flos-aquae NRC 525-17

Abstract Two cyclic peptides, anabaenopeptins A ( 1 ) and B ( 2 ), were isolated as a third group of bioactive compounds from Anabaena flos-aquae NRC 525-17. Their structures were determined by 2D-NMR techniques and Marfeys method combined with LC/MS.

COMPARATIVE STUDY OF TOXIC AND NON-TOXIC CYANOBACTERIAL PRODUCTS : NOVEL PEPTIDES FROM TOXIC NODULARIA SPUMIGENA AV1

Abstract Two types of novel peptides, cyclic peptides, nodulapeptins A (1) and B (2) and linear peptides, spumigins A∼C (3∼6), were isolated together with nodularin from toxic Nodularia spumigena AV1. Their structures were determined by 2D-NMR techniques, the advanced Marfeys method and MS/MS experiments.

Distribution of betaine lipids in marine algae

Abstract DGCC(1,2-diacylglyceryl-3-( O -carboxyhydroxymethylcholine)) is a betaine lipid derived from Pavlova lutheri . The separation of this lipid from other polar lipids by HPLC was improved in order to survey the distribution of DGCC, other betaine lipids and PC (phosphatidylcholine) in marine algae. DGCC was found to be one of the common constituents of Haptophyceae; it was interesting to note that PC was not detected even as a minor component. DGTA(1,2-diacylglyceryl- O -2′-(hydroxymethyl)-( N , N , N -trimethyl)- β -alanine) was detected in five out of 16 species of Haptophyceae, whereas DGTS(1,2-diacylglyceryl- O -4′-( N , N , N -trimethyl)homoserine) was not detected. DGCC was also detected in four strains of Dinophyceae and a strain of Bacillariophyceae. Acyl moieties of DGCC in Haptophyceae were 16:0, 18:0 or 18:1 and C 20 or C 22 polyunsaturated fatty acids.

Mechercharmycins A and B, cytotoxic substances from marine-derived Thermoactinomyces sp. YM3-251.

A new cytotoxic substance named mechercharmycin A was isolated from marine-derived Thermoactinomyces sp. YM3-251. The structure of mechercharmycin A was determined by an X-ray crystallographic analysis to be cyclic peptide-like and bearing four oxazoles and a thiazole. Mechercharmycin B, a linear congener of mechercharmycin A, was also isolated from the same bacterium. Mechercharmycin A exhibited relatively strong antitumor activity, whereas mechercharmycin B exhibited almost no such activity.

Inhibitory effect of bacterial ubiquinones on the settling of barnacle,Balanus amphitrite

In an attempt to clarify the influence of marine bacteria on the settling of fouling invertebrate larvae, we screened for inhibitors, produced by marine bacteria, of settling by cyprids of the barnacle,Balamus amphitrite. We found that the culture broth ofAlteromonas sp. strain number KK10304, which was associated with the marine sponge,Halichondria okadai, effectively inhibited settling of the cyprids. Bioassay-guided isolation indicated ubiquinone-8 (1) as an effective inhibitor of cyprid settling. As ubiquinones are widely distributed in bacteria, several related compounds were also tested.

Elucidation of a Carotenoid Biosynthesis Gene Cluster Encoding a Novel Enzyme, 2,2′-β-Hydroxylase, from Brevundimonas sp. Strain SD212 and Combinatorial Biosynthesis of New or Rare Xanthophylls

ABSTRACT A carotenoid biosynthesis gene cluster mediating the production of 2-hydroxyastaxanthin was isolated from the marine bacterium Brevundimonas sp. strain SD212 by using a common crtI sequence as the probe DNA. A sequence analysis revealed this cluster to contain 12 open reading frames (ORFs), including the 7 known genes, crtW, crtY, crtI, crtB, crtE, idi, and crtZ. The individual ORFs were functionally analyzed by complementation studies using Escherichia coli that accumulated various carotenoid precursors due to the presence of other bacterial crt genes. In addition to functionally identifying the known crt genes, we found that one (ORF11, named crtG) coded for a novel enzyme, carotenoid 2,2′-β-hydroxylase, which showed intriguingly partial homology with animal sterol-C5-desaturase. When this crtG gene was introduced into E. coli accumulating zeaxanthin and canthaxanthin, the resulting transformants produced their 2-hydroxylated and 2,2′-dihydroxylated products which were structurally novel or rare xanthophylls, as determined by their nuclear magnetic resonance and high-performance liquid chromatography/photodiode array detector/atmospheric pressure chemical ionization mass spectrometry spectral data. The new carotenoid produced was suggested to have a strong inhibitory effect on lipid peroxidation.

Three-dimensional Solution Structure of an Archaeal FKBP with a Dual Function of Peptidyl Prolyl cis-trans Isomerase and Chaperone-like Activities

Here we report the solution structure of an archaeal FK506-binding protein (FKBP) from a thermophilic archaeum, Methanococcus thermolithotrophicus (MtFKBP17), which has peptidyl prolyl cis-trans isomerase (PPIase) and chaperone-like activities, to reveal the structural basis for the dual function. In addition to a typical PPIase domain, a newly identified domain is formed in the flap loop by a 48-residue insert that is required for the chaperone-like activity. The new domain, called IF domain (the Insert in the Flap), is a novel-folding motif and exposes a hydrophobic surface, which we consider to play an important role in the chaperone-like activity.

Thermozeaxanthins, new carotenoid-glycoside-esters from thermophilic eubacterium thermus thermophilus

Abstract New zeaxanthin-(di)glucoside-branched fatty acid esters, thermozeaxanthin-13, −15, and −17 ( 1–3 ), thermobiszeaxanthin-13-13, −13–15, and −15-15 ( 4–6 ) were isolated from the thermophilic eubacterium Thermus thermophilus . Their structures were determined by spectral means. The membrane of this thermophilic bacterium is thought to be stabilized by these carotenoids.

β-cyanoalanine production by marine bacteria on cyanide-free medium and its specific inhibitory activity toward cyanobacteria

ABSTRACT In screening the culture broth of marine bacteria collected at Yap (Micronesia), Palau (Belau), and Okinawa (the southwest islands of Japan) for antimicroalgal activity, 37 out of 2,594 bacterial isolates tested were found to produce anticyanobacterial substances against Oscillatoria amphibia NIES-361. One strain, C-979, identified as a Vibrio sp., was selected and cultured in 2.4 liters of marine broth 2216 to identify the bioactive compound produced by the strain. The purified very hydrophilic compound (16.4 mg) was determined to be β-cyano-l-alanine (l-CNAla) by instrumental analyses and the application of the advanced Marfey method. l-CNAla did not inhibit the growth of bacteria, yeast, or eukaryotic microalgae, but some cyanobacteria were found to be sensitive to l-CNAla at a concentration of 0.4 to 25 μg/ml. The effect of l-CNAla on some other environmental organisms, including invertebrates and a macroalgae, is discussed. CNAla production in marine broth was examined by thin-layer chromatography for the 37 bacterial isolates which produced an anticyanobacterial substance. The broth of 36 of these strains contained CNAla, suggesting the wide distribution of CNAla production by marine bacteria. This is the first report on bacteria that produce CNAla without a supply of the cyanide ion in the medium.

Endozoicomonas numazuensis sp. nov., a gammaproteobacterium isolated from marine sponges, and emended description of the genus Endozoicomonas Kurahashi and Yokota 2007.

Two non-motile, rod-shaped gammaproteobacteria were isolated from marine sponges collected from the coast of Japan at Numazu. The isolates were oxidase- and catalase-positive facultative anaerobes that fermented carbohydrates. They required sodium ions for growth and were slightly halophilic, growing in the presence of 1.0-5.0 % (w/v) NaCl (optimum of 2.0 % NaCl). Under aerobic conditions, the major isoprenoid quinones were ubiquinone-9 and menaquinone-9 and the minor quinones were ubiquinone-8 and menaquinone-8. The major cellular fatty acids were C(18 : 1)ω7c, C(16 : 1)ω7c and C(16 : 0) and the hydroxy acids were C(10 : 0) 3-OH and C(12 : 0) 3-OH. The DNA G+C content was 48.3-48.7 mol%. Phylogenetic analysis of 16S rRNA gene sequences placed the isolates within the radiation of the genus Endozoicomonas in a broad clade of uncultured clones recovered from various marine invertebrates. The isolates exhibited 96.5-96.9 % 16S rRNA gene sequence similarity with Endozoicomonas elysicola MKT110(T) and Endozoicomonas montiporae CL-33(T), with which the isolates formed a monophyletic cluster with 100 % bootstrap support. The phenotypic features (carbohydrate fermentation, quinone system and some major cellular fatty acids) differed from those of members of the genus Endozoicomonas, which are aerobic, produce little or no menaquinone under aerobic conditions and possess different amounts of C(14 : 0) and C(18 : 1)ω7c. Although some phenotypic differences were identified, the isolates should be assigned to the genus Endozoicomonas on the basis of congruity of phylogeny and should be classified as representatives of a novel species, for which the name Endozoicomonas numazuensis sp. nov. is proposed. The type strain is HC50(T) ( = NBRC 108893(T)  = DSM 25634(T)). An emended description of the genus Endozoicomonas is presented.