Microbacterium abyssi sp. nov. and Microbacterium limosum sp. nov., two new species of the genus Microbacterium, isolated from deep-sea sediment samples.

Two Gram-positive, non-motile, short rod-shaped actinomycete strains, designated as A18JL241T and Y20T, were isolated from deep-sea sediment samples collected from the Southwest Indian Ocean and Western Pacific Ocean, respectively. Both of the isolates were able to grow within the temperature range of 5-40 °C, NaCl concentration range of 0-7  % (w/v) and at pH 6.0-12.0. The two most abundant cellular fatty acids of both strains were anteiso-C15  :  0 and anteiso-C17  :  0. The major polar lipid contents of the two strains were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and one unidentified glycolipid. These two strains shared common chemotaxonomic features comprising MK-10 and MK-12 as the respiratory quinones. The genomic DNA G+C contents of the two strains were 68.1 and 70.4  mol%, respectively. The 16S rRNA gene phylogeny showed that the novel strains formed two distinct sublines within the genus Microbacterium. Strain A18JL241T was most closely related to the type strain of Microbacterium tenebrionis KCTC 49593T (98.8 % sequence similarity), whereas strain Y20T formed a tight cluster with the type strain of Microbacterium schleiferi NBRC 15075T (99.0 %). The orthologous average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values with the type strains of related Microbacterium species were in the range of 74.1-89.1  % and 19.4-36.9  %, respectively, which were below the recognized thresholds of 95-96 % ANI and 70 % dDDH for species definition. Based on the results obtained here, it can be concluded that strains A18JL241T and Y20T represent two novel species of the genus Microbacterium, for which the names Microbacterium abyssi sp. nov. (type strain A18JL241T=JCM 33956T=MCCC 1A16622T) and Microbacterium limosum sp. nov. (type strain Y20T=JCM 33960T=MCCC 1A16747T) are proposed.

New Phthalides and Isochromanone Derivatives from the Deep-Sea-Derived Fungus Penicillium bialowiezense A3.

Two new phthalide derivatives, namely bialowalides A (1) and B (8), and one new isochromanone analogue biourgalide C (11), together with 8 known phthalides (2-7, 9, and 10) as well as two known isochromanones (12 and 13) were discovered from the EtOAc extract of the deep-sea-derived fungus Penicillium bialowiezense A3. The structures were resolved on the basis of extensive spectroscopic analyses (NMR and HRESIMS data), in association with the modified Mosher's method and ECD data for the determination of the absolute configurations. All isolated secondary metabolites (1-13) were tested their antiviral activities against the SARS-CoV-2 trVLP pseudovirus at a concentration of 25 µM. As a result, compounds 1, 5, 11, and 12 exhibited the inhibitory effects against the luminescence at 46.2 %, 39.6 %, 45.5 %, and 48.8 %, respectively.

Nocardioides cremeus sp. nov., Nocardioides abyssi sp. nov. and Nocardioides oceani sp. nov., three actinobacteria isolated from Western Pacific Ocean sediment.

Three Gram-stain-positive, non-motile, short rod-shaped, catalase-positive and oxidase-negative actinomycete strains (SOB44T, SOB72T and SOB77T) were isolated from a deep-sea sediment sample collected from the Western Pacific Ocean. Cells of the three strains showed optimum growth at 30 °C and pH 7.0. Strains SOB44T, SOB72T and SOB77T could tolerate up to 10, 9 and 9 % (w/v) NaCl concentration and grow at pH 5.0-12.0, 5.0-11.0 and 5.0-11.0, respectively. Phylogenetic results based on 16S rRNA gene sequences showed that the three isolates belonged to the genus Nocardioides and were identified as representing three novel species based on 78.0-93.1 % average nucleotide identity and 21.3-50.0 % DNA-DNA hybridization values with closely related reference strains. Strains SOB44T, SOB72T and SOB77T showed highest 16S rRNA gene sequence similarity to Nocardioides salarius CL-Z59T (99.2 %), Nocardioides deserti SC8A-24T (99.2 %) and Nocardioides marmotae zg-579T (98.5 %), respectively. All three strains had MK-8(H4) as the respiratory quinone, iso-C16 : 0 as the major fatty acid, and phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol as the major polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan of all three isolates was ll-diaminopimelic acid. The DNA G+C contents of strains SOB44T, SOB72T and SOB77T were 71.1, 72.9 and 72.9 mol%, respectively. Based on the phenotypic, phylogenetic and genotypic data, strains SOB44T, SOB72T and SOB77T clearly represent three novel taxa within the genus Nocardioides, for which the names Nocardioides cremeus sp. nov. (type strain SOB44T=JCM 35774T= MCCC M28400T), Nocardioides abyssi sp. nov. (type strain SOB72T=JCM 35775T=MCCC M28318T) and Nocardioides oceani sp. nov. (type strain SOB77T=JCM 35776T=MCCC M28544T) are proposed.

Antiviral Cyclopropane Acids from Deep-Sea-Derived Fungus Aspergillus sydowii.

Four novel monocyclic cyclopropane acids, namely, sydocyclopropanes A-D (1-4), along with one known congener hamavellone B (5), were isolated from the Aspergillus sydowii MCCC 3A00324 fungus, which was isolated from the deep-sea sediment. The gross structures of novel compounds were established by detailed analyses of the spectroscopic data (HRESIMS and NMR spectra), and their absolute configurations were resolved on the basis of the quantum chemical calculations of ECD and NMR data, in association with DP4+ probability analyses. Sydocyclopropanes A-D, featuring the 1,1,2,3-tetrasubstituted cyclopropane nucleus with different lengthy alkyl side chains, were discovered in nature for the first time. All compounds exhibited antiviral activities against A/WSN/33 (H1N1), with IC50 values ranging from 26.7 to 77.2 µM, of which compound 1 exhibited a moderate inhibitory effect (IC50 = 26.7 µM).

Phenolic Metabolites from a Deep-Sea-Derived Fungus Aspergillus puniceus A2 and Their Nrf2-Dependent Anti-Inflammatory Effects.

Four undescribed phenolic compounds, namely asperpropanols A-D (1-4), along with two known congeners 5 and 6, were isolated from Aspergillus puniceus A2, a deep-sea-derived fungus. The gross structures of the compounds were established by detailed analyses of the HRESIMS and NMR data, and their absolute configurations were resolved by modified Mosher's method and calculations of ECD data. Compounds 1-6 were found to have excellent anti-inflammatory effect on lipopolysaccharide (LPS)-induced RAW264.7 cells at 20 µM, evidenced by the reduced nitric oxide (NO), tumor necrosis factor α, and interleukin 6 production. Among them, 5 and 6 showed inhibitory effects on NO production comparable with the positive control (BAY11-7083 at 10 µM). Additionally, the LPS-induced mRNA expressions of inducible nitric oxide synthase and cyclooxygenase-2 were also decreased. Interestingly, mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2) was downregulated by LPS and recovered by 1-6, suggesting a vital role of Nrf2 in their effect. We further found that pharmacological inhibition of Nrf2 by ML385 largely abrogated the effects of 1-6 on RAW264.7 cells. Therefore, 1-6 may share a common anti-inflammatory mechanism via Nrf2 upregulation and activation.

A rapid and efficient method for the extraction and identification of menaquinones from Actinomycetes in wet biomass.

BACKGROUND: Menaquinones are constituents of prokaryote cell membranes where they play important functions during electron transport. Menaquinone profiles are strongly recommended for species classification when proposing a new Actinomycetes taxon. Presently, the most widely used methods to determine menaquinones are based on freeze-dried cells. Taxonomic research in our lab has revealed that menaquinone concentrations are low for some species of the genus Microbacterium, leading to difficulties in identifying menaquinones. RESULTS: Menaquinones extracted using the novel lysozyme-chloroform-methanol (LCM) method were comparable in quality to those obtained using the Collins method, the most widely used method. All tested strains extracted via the LCM method showed higher concentrations of menaquinones than those extracted via the Collins method. For some Microbacterium strains, the LCM method exhibited higher sensitivity than the Collins method, and more trace menaquinones were detected with the LCM method than the Collins method. In addition, LCM method is faster than the Collins method because it uses wet cells. CONCLUSION: The LCM method is a simple, rapid and efficient technique for the extraction and identification of menaquinones from Actinomycetes.

Complete genome sequence of Streptomyces sp. HSG2 from rhizosphere soil of mangrove in Qingmei Gang, Sanya.

Streptomyces sp. HSG2 was isolated from rhizosphere soil of a mangrove forest sample at Qingmei Gang, Sanya. The complete genome sequence of the strain HSG2 was obtained using PacBio Sequel HGAP.4 and comprised of 5,282,528 base pairs with a 71.9 mol% G + C content, 4504 protein-coding genes, and 71 RNAs. An in-silico analysis confirmed that genes associated with polysaccharide hydrolyzation, hydrocarbon degradation, and aerobic denitrification were presented in the genome. We also identified 24 natural product biosynthetic gene clusters for secondary metabolites, including those for streptobactin and nystatin A1. The complete genome sequence indicated that Streptomyces sp. HSG2 will provide insight into the biosynthesis and regulatory mechanisms for its secondary metabolites, and propose a potential use in biotechnological and novel bioactive natural product biosynthetic applications.

Nesterenkonia sedimenti sp. nov., isolated from marine sediment.

A Gram-staining-positive actinobacteria strain, designated MY13T, was isolated from deep-sea sediment of the western Pacific Ocean and subjected to a taxonomic polyphasic investigation. Based on the results, cells were aerobic, irregular short rod, non-motile and non-spore-forming. Colonies were cream, circular, smooth, convex, opaque and 1.0-2.0 mm in diameter after growth on MZ2 medium at 40 °C for 72 h. Strain MY13T grew at 4-50 °C (optimum, 40 °C), pH 7-12 (pH 9) and 0.5-15% (w/v) NaCl (3.5%). The 16S rRNA gene sequence analysis revealed that strain MY13T is affiliated with the genus Nesterenkonia and closely related to Nesterenkonia populi GP10-3T (96.6%). Digital DNA-DNA hybridization (dDDH) values and average nucleotide identity (ANI) differentiated it from its closest relatives, with values ranging from 19.8% to 22.4% and 72.6% to 78.0%, respectively. Chemotaxonomic analysis showed that the major menaquinone of strain MY13T was MK-7; major cellular fatty acids were anteiso-C17:0, anteiso-C15:0 and iso-C16:0; whole-cell sugars were galactose and xylose; the peptidoglycan type was L-Lys-Gly-D-Asp; and polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unknown glycolipids, one unknown polar lipid and two unknown lipids. The G+C content of genomic DNA was 63.1 mol%. Based on the physiological, chemotaxonomic and phylogenetic data, strain MY13T is a novel species of the genus Nesterenkonia, for which the name Nesterenkonia sedimenti sp. nov. is proposed. The type strain is MY13T (= LMG 28111T = MCCC 1A09979T = JCM 19767T = CGMCC 1.12784T).

Chryseoglobus indicus sp. nov., isolated from deep sea water.

A novel Gram-stain-positive, motile, aerobic, non-spore-forming and slender rod-shaped actinobacterium, designated strain CTD02-10-2T, was isolated from deep sea water of the Indian Ocean. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain CTD02-10-2T was grouped into a separated branch with Chryseoglobus frigidaquae JCM 14730T (98.4 % nucleotide sequence identity). The respiratory quinones were menaquinones with 11, 12, 13 and 14 isoprene units and anteiso-C15 : 0, iso-C16 : 0, anteiso-C15 : 1 A and anteiso-C17 : 0 were the major fatty acids. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and three unknown glycolipids. The genome of strain CTD02-10-2T was 2.59 Mb, with a DNA G+C content of 69.6 mol% and contained genes involved in the biosynthesis of alkylresorcinol, ansamycin, and carotenoids. In silico DNA-DNA hybridization and average nucleotide identity values for whole-genome sequence comparisons between strain CTD02-10-2T and C. frigidaquae JCM 14730T were clearly below the thresholds used for the delineation of a new species. Based on its morphological and chemotaxonomic characteristics, as well as genotypic data, strain CTD02-10-2T was classified as a novel species of the genus Chryseoglobus, for which the name Chryseoglobus indicus sp. nov. is proposed. The type strain is CTD02-10-2T (=JCM 33842T=MCCC 1A16619T).

Microcella flavibacter sp. nov., isolated from marine sediment, and reclassification of Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov.

A novel Gram-staining positive, aerobic, rod-shaped, non-motile and yellow-pigmented actinobacterium, designated strain WY83T, was isolated from a marine sediment of Indian Ocean. Strain WY83T grew optimally at 30-35 °C, pH 7-8 and with 0-3% (w/v) NaCl. The predominant menaquinones were MK-10, MK-11 and MK-12, and the major fatty acids were C19:1 ω9c/C19:1 ω11c, anteiso-C15:0, C17:0 3OH, and iso-C16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The cell-wall peptidoglycan contained lysine as a diamino acid. The DNA G + C content was 72.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and ninety-two bacterial core genes indicated that strain WY83T formed an evolutionary lineage with Chryseoglobus frigidaquae JCM 14730T, Chryseoglobus indicus CTD02-10-2T, Yonghaparkia alkaliphila JCM 15138T, Microcella alkaliphila DSM 18851T and Microcella putealis DSM 19627T within the radiation enclosing members of the family Microbacteriaceae. All pairwise percentage of conserved proteins between strain WY83T and the closely related phylogenetic neighbors were greater than 65%. The average nucleotide identity and in silico DNA-DNA hybridization values were both below the thresholds used for the delineation of a new species. On the basis of the evidence presented, strains WY83T, Y. alkaliphila JCM 15138T, C. frigidaquae JCM 14730T, M. alkaliphila DSM 18851T and M. putealis DSM 19627T should belong to different species of the same genus. Strain WY83T represents a novel species of the genus Microcella, for which the name Microcella flavibacter sp. nov. is proposed. The type strain is WY83T (= KCTC 39637T = MCCC 1A07099T). Furthermore, Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila were reclassified as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov., respectively.

Nesterenkonia salmonea sp. nov. and Nesterenkonia sphaerica sp. nov., isolated from the Southern Atlantic Ocean.

Two Gram-positive, aerobic, non-motile and non-spore-forming actinobacteria, strains GY074T and GY239T, were isolated from deep-sea sediment of the Southern Atlantic Ocean. The results of phylogenetic analysis of 16S rRNA gene sequences placed both isolates within the genus Nesterenkonia, and showed a sequence similarity of 98.3 % between the two strains and similarites of 94.3-97.2 % with respect to Nesterenkonia species with validly published names. Based on whole-genome sequences, the values of in silico DNA-DNA hybridization and the average nucleotide identity between strains GY074T and GY239T were 21.2 and 78.1 %, respectively, less than the proposed cut-off level for species delineation, i.e. 70 and 95 %. For both strains, the major cellular fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0, and the major menaquinones were MK-7, MK-8 and MK-9. The major polar lipid contents of the two strains were similar with phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid. The genomic DNA G+C contents of strains GY074T and GY239T were 61.1 and 64.2 mol%, respectively. On the basis of the phylogenetic analysis and physiological and chemotaxonomic data, the isolates represent two novel species of the genus Nesterenkonia, for which the names Nesterenkonia salmonea sp. nov. (type strain GY074T=KCTC 39639T=MCCC 1A11256T) and Nesterenkonia sphaerica sp. nov. (type strain GY239T=KCTC 39640T=MCCC 1A10688T) are proposed.

Brevibacterium profundi sp. nov., isolated from deep-sea sediment of the Western Pacific Ocean.

A new Gram-stain-positive, aerobic, non-motile and rod-shaped actinobacterium, designated O1T, was isolated from a deep-sea sediment of the Western Pacific Ocean. Strain O1T showed optimal growth at 30 °C, between pH 6.0 and 8.0, and in the presence of 1-5 % (w/v) NaCl. The predominant menaquinone was MK-8 (H2), and anteiso-C15 : 0 and anteiso-C17 : 0 were the major fatty acids. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and one unknown glycolipid. The DNA G+C content of strain O1T was 64.9 mol% and the genome size was 4.17 Mb. Based on a similarity search and phylogenetic analysis of the 16S rRNA gene sequence, strain O1T belonged to the genus Brevibacterium. The values of average nucleotide identity and in silico DNA-DNA hybridization between strain O1T and its close relatives were well below the thresholds used for the delineation of a new species. On the basis of the morphological and chemotaxonomic characteristics, as well as the genotypic data, it is proposed that strain O1T represents a novel species of the genus Brevibacterium, for which the name Brevibacterium profundi sp. nov. is proposed. The type strain is O1T (=JCM 33845T=MCCC 1A16744T).

Saccharopolyspora coralli sp. nov. a novel actinobacterium isolated from the stony coral Porites.

A novel Gram-stain-positive, aerobic, non-motile actinobacterium, designated strain E2AT, was isolated from a coral sample and examined using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain E2AT formed a distinct phyletic lineage in the genus Saccharopolyspora and was closely related to S. cavernae CCTCC AA 2012022T (96.4 %) and S. lacisalsi CCTCC AA 2010012T (95.3 %). The isolate grew at 15-35 °C, pH 5-12 and in the presence of 1-16 % (w/v) NaCl. The cell-wall diamino acid was meso-DAP. Major fatty acids identified were iso-C15 : 0, iso-C16 : 0 and C17 : 1 ω8c. The predominant menaquinone was MK-9(H4). The polar lipids detected were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, one unidentified glycolipid, one unidentified phospholipid and one unidentified aminolipid. The genomic DNA G+C content was 68.6 mol%. Based on the data from the polyphasic taxonomic study reported here, strain E2AT represents a novel species within the genus Saccharopolyspora, for which the name Saccharopolyspora coralli sp. nov. is proposed. The type strain is E2AT=(JCM 31844T=MCCC 1A17150T).

Phenolic bisabolane and cuparene sesquiterpenoids with anti-inflammatory activities from the deep-sea-derived Aspergillus sydowii MCCC 3A00324 fungus.

Seventeen undescribed sesquiterpenoids including 14 phenolic bisabolanes, namely asperbisabolanes A-N (1-14), and 3 cuparenes (aspercuparenes A-C, 15-17), together with 10 known bisabolane analogues (18-27) were isolated from the EtOAc extract of fermented cultures of the deep sea sediment-derived fungus Aspergillus sydowii MCCC 3A00324. The new structures were established on the basis of extensive NMR and HRESIMS spectroscopic data analyses, while their absolute configurations were assigned by comparison of the experimental ECD spectra with those of the TDDFT-ECD calculated spectra or reported data in literature. Asperbisabolanes A (1) and B (2) are the first examples of bisabolane sesquiterpenoids featuring a 6/6/6 tricyclic nucleus. Compound 3 possessed a novel seco-bisabolane skeleton with a rare dioxolane ring moiety, while asperbisabolane K (11) represents the first case of bisabolanes bearing a rare methylsulfonyl group. All the isolated compounds (1-27) were evaluated their activities against NO secretion in LPS-activated BV-2 microglia cells. As a result, 6, 12, 16, and 25-27 exhibited the inhibition rate over 45% at a concentration of 10 µM. Moreover, 12 exerted the anti-inflammatory activity by inhibiting the NF-κB-activated pathway in dose-dependent manner.

New Monoterpenoids and Polyketides from the Deep-Sea Sediment-Derived Fungus Aspergillus sydowii MCCC 3A00324.

Chemical study of the secondary metabolites of a deep-sea-derived fungus Aspergillus sydowii MCCC 3A00324 led to the isolation of eleven compounds (1-11), including one novel (1) and one new (2) osmane-related monoterpenoids and two undescribed polyketides (3 and 4). The structures of the metabolites were determined by comprehensive analyses of the NMR and HRESIMS spectra, in association with quantum chemical calculations of the 13C NMR, ECD, and specific rotation data for the configurational assignment. Compound 1 possessed a novel monoterpenoid skeleton, biogenetically probably derived from the osmane-type monoperpenoid after the cyclopentane ring cleavage and oxidation reactions. Additionally, compound 3 was the first example of the α-pyrone derivatives bearing two phenyl units at C-3 and C-5, respectively. The anti-inflammatory activities of 1-11 were tested. As a result, compound 6 showed potent inhibitory nitric oxide production in lipopolysaccharide (LPS)-activated BV-2 microglia cells with an inhibition rate of 94.4% at the concentration of 10 µM. In addition, a plausible biosynthetic pathway for 1 and 2 was also proposed.

Paracoccus subflavus sp. nov., isolated from Pacific Ocean sediment.

A Gram-stain-negative, short rod-shaped, non-motile, catalase- and oxidase-positive, aerobic bacterium, designated GY0581T, was isolated from marine sediment sampled from the Western Pacific Ocean. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain GY0581T belonged to the genus Paracoccus and had the highest levels of sequence similarity to Paracoccus sediminis JCM 18467T (98.2 %). Levels of similarity between strain GY0581T and other Paracoccus species were lower than 97.0 %. The average nucleotide identity and the DNA-DNA hybridization values between strain GY0581T and P. sediminis JCM 18467T were 83.9 and 27 %, respectively, which are below the respective thresholds for species differentiation. The major cellular fatty acid was C18 : 1ω7c (79.5 %). The only isoprenoid quinone was Q-10. The polar lipid pattern indicated the presence of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, three unidentified phospholipids, three unidentified aminolipids, one unidentified glycolipid and two unidentified lipids. The DNA G+C content of strain GY0581T was 65.6 mol%. On the basis of polyphasic characterization, it is concluded that strain GY0581T represents a novel species of the genus Paracoccus, for which the name Paracoccus subflavus sp. nov. is proposed. The type strain is GY0581T (=KCTC 42710T=MCCC 1A10575T).

Cytotoxic Polyketides Isolated from the Deep-Sea-Derived Fungus Penicillium chrysogenum MCCC 3A00292.

The chemical examination of the solid cultures of the deep-sea-derived fungus Penicillium chrysogenum MCCC 3A00292 resulted in the isolation of three new versiol-type analogues, namely peniciversiols A-C (1-3), and two novel lactone derivatives, namely penicilactones A and B (6 and 7), along with 11 known polyketides. The planar structures of the new compounds were determined by the comprehensive analyses of the high-resolution electrospray ionization mass spectroscopy (HRESIMS) and nuclear magnetic resonance (NMR) data, while their absolute configurations were resolved on the basis of comparisons of the experimental electronic circular dichroism (ECD) spectra with the calculated ECD data. Compound 1 is the second example of versiols featuring a 2,3-dihydropyran-4-one ring. Additionally, compounds 6 and 7 are the first representatives of γ-lactone derivatives constructed by a 1,3-dihydroxy-5-methylbenzene unit esterifying with the α-methyl-γ-hydroxy-γ-acetic acid α,ß-unsaturated-γ-lactone moiety and α-hydroxy-γ-methyl-γ-acetic acid α,ß-unsaturated-γ-lactone unit, respectively. All of the isolated compounds were evaluated for their cytotoxic activities against five human cancer cell lines of BIU-87, ECA109, BEL-7402, PANC-1, and Hela-S3. Compound 1 exhibited a selective inhibitory effect against the BIU-87 cell line (IC50 = 10.21 µM), while compounds 4, 5, 8, and 12-16 showed inhibitory activities against the ECA109, BIU-87, and BEL-7402 cell lines with the IC50 values ranging from 7.70 to > 20 µM.

Production and Identification of Inthomycin B Produced by a Deep-Sea Sediment-Derived Streptomyces sp. YB104 Based on Cultivation-Dependent Approach.

The natural products discovery program in our group utilizes deep-sea sediment-derived microorganisms and employs a bio-active guided isolation procedure and one strain many compounds (OSMAC) approach to screen bio-active natural products for practical applications in the medicinal and agricultural industry. OSMAC strategy is employed to stimulate secondary metabolite production through changing culture conditions. In this paper, we applied cultivation-dependent procedure, changing media type, leading to the discovery of a bio-active compound named inthomycin B (1) from a marine-derived Streptomyces sp. YB104. The compound was characterized based on extensive spectroscopic analyses and comparison to that in the reported literature. The quantification of inthomycin B demonstrated that Streptomyces sp. YB104 produced moderate yield of inthomycin B with a yield around 25 mg/l after 14 days. Thus, Streptomyces sp. YB104 was considered to be a useful potential as a first industrial-producing strain of inthomycins.

Albisporachelin, a New Hydroxamate Type Siderophore from the Deep Ocean Sediment-Derived Actinomycete Amycolatopsisalbispora WP1T.

Marine actinobacteria continue to be a rich source for the discovery of structurally diverse secondary metabolites. Here we present a new hydroxymate siderophore produced by Amycolatopsis albispora, a recently described species of this less explored actinomycete genus. Strain WP1T was isolated from sediments collected at -2945 m in the Indian Ocean. The new siderophore, designated albisporachelin, was isolated from iron depleted culture broths and the structure was established by 1D and 2D NMR and MS/MS experiments, and application of a modified Marfey's method. Albisporachelin is composed of one N-methylated-formylated/hydroxylated l-ornithine (N-Me-fh-l-Orn), one l-serine (l-Ser), one formylated/hydroxylated l-ornithine (fh-l-Orn) and a cyclo-N-methylated-hydroxylated l-ornithine (cyclo-N-Me-h-l-Orn).

Pseudonocardia profundimaris sp. nov., isolated from marine sediment.

A novel Gram-stain-positive, aerobic, non-motile actinobacterium, designated GY0556T, was isolated from deep-sea sediment collected from the western Pacific Ocean at a depth of 7118 m. Phylogenetic analysis based on 16S rRNA gene sequences revealed that this strain belongs to the genus Pseudonocardia, being most closely related to Pseudonocardia hydrocarbonoxydans IMSNU 22140T (97.6 % similarity), Pseudonocardia sulfidoxydans DSM 44248T (97.6 %) and Pseudonocardia alaniniphila Y-16303T (97.6 %); similarity to other type strains of the genus Pseudonocardia was less than 97.5 %. Strain GY0556T contained MK-8(H4) as the predominant menaquinone and iso-C16 : 0 and iso H-C16 : 1 as the major fatty acids. The polar lipids detected in strain GY0556T were phosphatidylcholine, phosphatidylinositol, one unknown glycolipid, one unknown phospholipid and two unknown lipids. The whole organism hydrolysates mainly consisted of meso-diaminopimelic acid, xylose, galactose and arabinose. The DNA G+C content of strain GY0556T was 76.9 mol%. The results of DNA-DNA hybridizations and phylogenetic analysis, together with the phenotypic and biochemical tests, allowed the differentiation of strain GY0556T from established members of the genus Pseudonocardia. Therefore, it is proposed that strain GY0556T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia profundimaris sp. nov. is proposed. The type strain is GY0556T (=MCCC 1A10574T=KCTC 39641T).