New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• cereus and Kocuria rhizophila. We subsequently investigated the antimicrobial properties of 1 against several known Gram-negative plant pathogens isolated from the same collection site as Variovorax sp. H002. Remarkably, variochelin A (1) moderately inhibited seven out of eight tested plant pathogens

• bacteria (Bacillus cereus NBRC 15305 and Kocuria rhizophila NBRC 12708). In addition, several in-house collections of plant pathogens including Erwinia rhapontici_D020, Pantoea agglomerans_G054_1, Agrobacterium tumefaciens_K021_1, Pseudomonas syringae_E029, Ralstonia basilensis_M004 and Paraburkholderia Sp

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• -positive bacteria, Kocuria rhizophila ATCC 9341 and Bacillus subtilis ATCC 6633; two strains of Gram-negative bacteria, Escherichia coli Europe NIHJ and Xanthomona campestis pv. oryzae KB 88; and two strains of fungi, Candida albicans ATCC 64548 and Mucor racemosus IFO 4581. All strains were tested by

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• Antimicrobial activity was examined as previously reported [41]. Kocuria rhizophila ATCC9341, Staphylococcus aureus FDA209P JC-1, Ralstonia solanacearum SUPP1541, Escherichia coli NIHJ JC-2, Rhizobium radiobacter NBRC14554, and Candida albicans NBRC0197 were used as indication strains. Cytotoxicity against 3Y1

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• were weakly inhibitory against Kocuria rhizophila at MIC 100 μg/mL and none were cytotoxic against P388 at the same concentration. Keywords: Couchioplanes; prenylated tryptophan; rare actinomycete; unsaturated fatty acid; Introduction Actinomycetes, a subgroup of filamentous Gram-positive bacteria

• , Rhizobium radiobacter and Escherichia coli, or a yeast Candida albicans (MIC > 100 μg/mL). Compounds 1–5 were marginally active against Kocuria rhizophila (MIC = 100 μg/mL). Conclusion In this study, five unsaturated fatty acids (1–5) and one prenylated tryptophan derivative (6) were isolated as new natural

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• absolute configuration was determined by combination of NOESY/ROESY and ECD analyses. Nomimicins B, C, and D showed antimicrobial activity against Gram-positive bacteria, Kocuria rhizophila and Bacillus subtilis, with MIC values in the range of 6.5 to 12.5 μg/mL. Nomimicins B and C also displayed

• antimicrobial activity against Kocuria rhizopila with a MIC value of 6.5 μg/mL and 1 and 2 were also active against Bacillus subtilis with a MIC value of 12.5 μg/mL. Compounds 1–3 were inactive against Staphylococcus aureus, Ralstonia solanacearum, Rhizobium radiobacter, and Candida albicans. In addition, 1 and

Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• of the genus Kocuria, isolated from a stony coral Mycedium sp., led to the identification of two new alkanoylimidazoles, nocarimidazoles C (1) and D (2) as well as three known congeners, nocarimidazoles A (3) and B (4) and bulbimidazole A (5). Structure analysis of 1 and 2 by NMR and MS revealed that

• MIC ranges of 6.25–25 μg/mL. Keywords: 1JC,H; alkanoylimidazoles; anteiso; Kocuria; nocarimidazole; Introduction The phylum Actinobacteria contains bacterial genera most prolific as producers of novel natural products with high structural diversity, unique modes of action, and potent bioactivities

• metabolite of marine Verrucosispora, effective against methicillin-resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis [11][12]. The genus Kocuria, formerly categorized in the genus Micrococcus, is a Gram-positive unicellular coccus belonging to the family Micrococcaceae [13]. Members of

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• chain of the spiroacetal rings, which showed clear contrast to other oligomycin congeners and related polyketides with ring-truncation or expansion. The new macrolides 2–4 displayed potent antimicrobial activity against the Gram-positive bacterium Kocuria rhizohpila and the plant pathogenic fungus

• examined in antimicrobial and cytotoxicity assays (Table 3). Pseudosporamide (1) was not active against all microorganisms tested in this study. Pseudosporamicin 2–4 were selectively active against the Gram-positive bacterium Kocuria rhizophila and the filamentous fungus Glomerella cingulate, but were