Isolation and identification of Streptomyces sp. Act4Zk, a good producer of Staurosporine and some derivatives

Lentzea sokolovensis sp. nov., Lentzea kristufekii sp. nov. and Lentzea miocenica sp. nov., rare actinobacteria from Miocene lacustrine sediment of the Sokolov Coal Basin, Czech Republic

The taxonomic position of three actinobacterial strains, BCCO 10_0061T, BCCO 10_0798T, and BCCO 10_0856T, recovered from bare soil in the Sokolov Coal Basin, Czech Republic, was established using a polyphasic approach. The multilocus sequence analysis based on 100 single-copy genes positioned BCCO 10_0061T in the same cluster as Lentzea waywayandensis, strain BCCO 10_0798T in the same cluster as Lentzea flaviverrucosa, Lentzea californiensis, Lentzea violacea, and Lentzea albidocapillata, and strain BCCO 10_0856T clustered together with Lentzea kentuckyensis and Lentzea alba. Morphological and chemotaxonomic characteristics of these strains support their assignment to the genus Lentzea. In all three strains, MK-9(H4) accounted for more than 80 % of the isoprenoid quinone. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The whole-cell sugars were rhamnose, ribose, mannose, glucose, and galactose. The major fatty acids (>10 %) were iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, and C16 : 0. The polar lipids were diphosphatidylglycerol, methyl-phosphatidylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylinositol. The genomic DNA G+C content of strains (mol%) was 68.8 for BCCO 10_0061T, 69.2 for BCCO 10_0798T, and 68.5 for BCCO 10_0856T. The combination of digital DNA-DNA hybridization results, average nucleotide identity values and phenotypic characteristics of BCCO 10_0061T, BCCO 10_0798T, and BCCO 10_0856T distinguishes them from their closely related strains. Bioinformatic analysis of the genome sequences of the strains revealed several biosynthetic gene clusters (BGCs) with identities >50 % to already known clusters, including BGCs for geosmin, coelichelin, ε-poly-l-lysine, and erythromycin-like BGCs. Most of the identified BGCs showed low similarity to known BGCs (<50 %) suggesting their genetic potential for the biosynthesis of novel secondary metabolites. Based on the above results, each strain represents a novel species of the genus Lentzea, for which we propose the name Lentzea sokolovensis sp. nov. for BCCO 10_0061T (=DSM 116175T), Lentzea kristufekii sp. nov. for BCCO 10_0798T (=DSM 116176T), and Lentzea miocenica sp. nov. for BCCO 10_0856T (=DSM 116177T).

Isolation, Characterization of Pyraclostrobin Derived from Soil Actinomycete Streptomyces sp. HSN-01 and Its Antimicrobial and Anticancer Activity

The present study demonstrated the isolation, characterization, and antimicrobial and anticancer activity of active metabolite produced from mining-soil-derived actinomycetes. Among the 21 actinomycete isolates, the isolate HSN-01 exhibited significant antimicrobial activity in primary screening and was identified as Streptomyces sp. through 16S rRNA gene sequencing. The active metabolite was separated, purified, and confirmed through UV-Vis spectroscopy, FTIR, HR-ESI-MS, and NMR analysis and identified as pyraclostrobin. Further, the active metabolite pyraclostrobin was tested for antimicrobial and anticancer activity against the hepatocellular carcinoma (HepG2) cell line. The metabolite exhibited maximum antimicrobial potential with 17.0, 13.33, 17.66, 15.66, 14.66, and 14.0 mm of inhibition against B. cereus, S. aureus, E. coli, P. aeruginosa, S. flexneri, and C. glabrata. The active metabolite exhibited dose-dependent anticancer potential against the hepatocellular carcinoma (HepG2) cell line with the IC₅₀ 56.76 µg/mL. This study suggests that Streptomyces sp. HSN-01 is an excellent source of active secondary metabolites with various biological activities.

Bioproduction, purification and physicochemical characterization of melanin from Streptomyces sp. strain MR28

Melanin has been produced and extracted from various microorganisms because of its therapeutic nature and diverse applications in various fields. Hence we isolated actinomycetes from soil which is capable of producing melanin pigment from L-tyrosine and it was identified as Streptomyces sp. strain MR28 on the basis of biochemical, morphological characterization, and 16S rRNA gene sequencing. Production of melanin pigment was achieved by using standardized tyrosine broth. The melanin pigment was purified, and characterized by using various techniques such as Ultraviolet-Visible spectroscopy (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), Thin Layer Chromatography (TLC), ¹H NMR spectroscopy, Scanning Electron Microscopy (SEM), Elemental analysis (EDX), and Thermogravimetric analysis (TGA). The pigment exhibit maximum UV-Vis absorption spectrum at 299 nm, FTIR peaks confirm the occurrence of C-H, C-N, C-O, and CC functional groups which are key functional groups in indole/pyrrole structure. TLC analysis showed a single band with a significant Retardation factor (Rf) of 0.68, Resonance peaks at 6.66, 7.18, and 7.28 ppm exhibit aromatic hydrogen in the indole/pyrole system in ¹H NMR. The EDX reports the presence of carbon, nitrogen, oxygen, and sulfur which are key elements in melanin structure, and TGA exhibits the thermal stability of the melanin. Overall, the successful production and extraction of melanin was achieved by using soil actinomycetes Streptomyces sp. strain MR28, and its characterization confirms the nature of the melanin pigment which has significant value in the industrial and biomedical field.

Winogradskyella luteola sp.nov., Erythrobacter ani sp. nov., and Erythrobacter crassostrea sp.nov., isolated from the hemolymph of the Pacific Oyster Crassostrea gigas

Three new bacterial strains, WHY3^T, WH131^T, and WH158^T, were isolated and described from the hemolymph of the Pacific oyster Crassostrea gigas utilizing polyphasic taxonomic techniques. The 16S rRNA gene sequence analysis revealed that strain WHY3^T was a member of the genus Winogradskyella, whereas strains WHI31^T and WH158^T were members of the genus Erythrobacter. According to the polygenomic study the three strains formed individual lineages with strong bootstrap support. The comparison of dDDH-and ANI values, percentage of conserved proteins (POCP), and average amino acid identity (AAl) between the three strains and their relatives established that the three strains represented two separate genera. Menaquinone-6 was reported as the major respiratory quinone in strain WHY3^T and Ubiquinone-10 for strains WH131^T and WH158^T, respectively. The major cellular fatty acids for strain WHY3^T were C_15:0, anteiso-C_15:1 ω7c, iso-C_15:0, C_16:1ω7c. The major cellular fatty acids for strains WH131^T and WH158^T were C_14:02-OH and t_18:1ω12 for WH131^T and C_17:0, and C_18:1ω7c for strain WH158^T. Positive Sudan Black B staining Indicated the presence of polyhydroxyalkanoic acid granules for strains WH131^T and WH158^T but not for strain WHY3^T. The DNA G + C contents of strains WHY3^T, WH131^T and WH158^T were 34.4, 59.7 and 56.6%, respectively. Gene clusters predicted some important genes involved in the bioremediation process. Due to the accomplishment of polyphasic taxonomy, we propose three novel species Winogradskyella luteola sp.nov. (type strain WHY3^T = DSM 111804^T = NCCB 100833^T), Erythrobacter ani sp.nov. (WH131^T = DSM 112099^T = NCCB 100824^T) and Erythrobacter crassostrea sp.nov. (WH158^T = DSM 112102^T = NCCB 100877^T).

Corallococcus soli sp. Nov., a Soil Myxobacterium Isolated from Subtropical Climate, Chalus County, Iran, and Its Potential to Produce Secondary Metabolites

A novel myxobacterial strain ZKHCc1 1396^T was isolated in 2017 from a soil sample collected along Chalus Road connecting Tehran and Mazandaran, Iran. It was a Gram-negative, rod-shaped bacterial strain that displayed the general features of Corallococcus, including gliding and fruiting body formation on agar and microbial lytic activity. Strain ZKHCc1 1396^T was characterized as an aerobic, mesophilic, and chemoheterotrophic bacterium resistant to many antibiotics. The major cellular fatty acids were branched-chain iso-C_17:0 2-OH, iso-C_15:0, iso-C_17:1, and iso-C_17:0. The strain showed the highest 16S rRNA gene sequence similarity to Corallococcusterminator CA054A^T (99.67%) and C. praedator CA031B^T (99.17%), and formed a novel branch both in the 16S rRNA gene sequence and phylogenomic tree. The genome size was 9,437,609 bp, with a DNA G + C content of 69.8 mol%. The strain had an average nucleotide identity (ANI) value lower than the species cut-off (95%), and with the digital DNA–DNA hybridization (dDDH) below the 70% threshold compared to the closest type strains. Secondary metabolite and biosynthetic gene cluster analyses revealed the strain’s potential to produce novel compounds. Based on polyphasic taxonomic characterization, we propose that strain ZKHCc1 1396^T represents a novel species, Corallococcus soli sp. nov. (NCCB 100659^T = CIP 111634^T).

Photobacterium arenosum WH24, Isolated from the Gill of Pacific Oyster Crassostrea gigas from the North Sea of Germany: Co-cultivation and Prediction of Virulence

Cream colored bacteria from marine agar, strain WH24, WH77, and WH80 were isolated from the gill of the Crassostrea gigas a Pacific oyster with a filter-feeding habit that compels accompanying bacteria to demonstrate a high metabolic capacity, has proven able to colonize locations with changing circumstances. Based on the 16S rRNA gene sequence, all strains had high similarity to Photobacterium arenosum CAU 1568^T (99.72%). This study involved phenotypic traits, phylogenetic analysis, antimicrobial activity evaluation, genome mining, Co-cultivation experiments, and chemical studies of crude extracts using HPLC and LC-HRESIMS. Photobacterium arenosum WH24 and Zooshikella harenae WH53^Twere co-cultivated for 3 days in a rotary shaker at 160 rpm at 30 °C, and LC-MS monitored the chemical profiles of the co-cultures on the third day. The UV chromatograms of the extracts of the co-cultivation experiments show that Zooshikella harenae WH53^T could be inhibited by strain WH24. The high virulence of Photobacterium arenosum WH24 was confirmed by genome analysis. Gene groups with high virulence potential were detected: tssA (ImpA), tssB (ImpB/vipA), tssC (ImpC/vipB), tssE, tssF (ImpG/vasA), tssG (ImpH/vasB), tssM (IcmF/vasK), tssJ (vasD), tssK (ImpJ/vasE), tssL (ImpK/vasF), clpV (tssH), vasH, hcp, lapP, plpD, and tpsB family.

Meroterpenoids Possibly Produced by a Bacterial Endosymbiont of the Tropical Basidiomycete Echinochaete brachypora

A mycelial culture of the African basidiomycete Echinochaete cf. brachypora was studied for biologically active secondary metabolites, and four compounds were isolated from its crude extract derived from shake flask fermentations, using preparative high-performance liquid chromatography (HPLC). The pure metabolites were identified using extensive nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Aside from the new metabolites 1-methoxyneomarinone (1) and (E)-3-methyl-5-(-12,13,14-trimethylcyclohex-10-en-6-yl)pent-2-enoic acid (4), the known metabolites neomarinone (2) and fumaquinone (4) were obtained. Such compounds had previously only been reported from Actinobacteria but were never isolated from the cultures of a fungus. This observation prompted us to evaluate whether the above metabolites may actually have been produced by an endosymbiontic bacterium that is associated with the basidiomycete. We have indeed been able to characterize bacterial 16S rDNA in the fungal mycelia, and the production of the metabolites stopped when the fungus was sub-cultured on a medium containing antibacterial antibiotics. Therefore, we have found strong evidence that compounds 1–4 are not of fungal origin. However, the endofungal bacterium was shown to belong to the genus Ralstonia, which has never been reported to produce similar metabolites to 1–4. Moreover, we failed to obtain the bacterial strain in pure culture to provide final proof for its identity. In any case, the current report is the first to document that polyporoid Basidiomycota are associated with endosymbionts and constitutes the first report on secondary metabolites from the genus Echinochaete.

Qipengyuania pacifica sp. nov., a Novel Carotenoid-Producing Marine Bacterium of the Family Erythrobacteraceae, Isolated from Sponge (Demospongiae), and Antimicrobial Potential of Its Crude Extract

A marine Alphaproteobacterium designated as strain NZ-96T was isolated in February 2021, from a sponge species (Demospongiae) collected in muddy sediments with boulders and old chimneys in Otago/Canterbury Slope, Pacific Ocean, New Zealand. The isolate was found to be Gram-negative, rod-shaped, aerobic, motile, and produced yellow-colored colonies. The isolate was positive for alkaline phosphatase, leucine arylamidase, trypsin, catalase, and oxidase and negative for α-galactosidase and urease. It was resistant to many antibiotics including hygromycin, trimethoprim, spectinomycin, ampicillin, oxytetracycline, cephalosporin, bacitracin, and polymyxin. The 16S rRNA gene-based phylogenetic analyses exhibited that strain NZ-96T belonged to the genus Qipengyuania and showed 98.3–98.8% 16S rRNA gene sequence similarity to its closest relatives. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipid profile consisted of phosphatidylcholine, sphingoglycolipid, phosphatidylglycerol, one unknown polar lipid, and three unknown glycolipids. The major fatty acids were C18:1ω12t, C16:0, C16:1ω7c, C17:1ω6c, C16:02-OH, and C14:0 2-OH. Carotenoid were produced. The crude extract showed pronounced activity against Staphylococcus aureus Newman and Bacillus subtilis DSM 10. Pairwise ANI and dDDH values of strain NZ-96T and closely related phylogenetic hits were below the threshold values of 95% and 70%, respectively. Genes for trehalose biosynthesis, aspartate-semialdehyde dehydrogenase, flagellar biosynthesis, fatty acid biosynthesis, and antibiotics resistance were present, which aids in isolate survival in a sea or ocean environment. The DNA G+C content was 60.8% (by genome). Based on data obtained by the polyphasic approach, strain NZ-96T (= DSM 112811T = NCCB 100842T) represents a novel species of the genus Qipengyuania, for which the name Qipengyuania pacifica sp. nov. is proposed.

Ecological and Pharmacological Activities of Polybrominated Diphenyl Ethers (PBDEs) from the Indonesian Marine Sponge Lamellodysidea herbacea

Two known Polybrominated Diphenyl Ethers (PBDEs), 3,4,5-tribromo-2-(2′,4′-dibromophenoxy)phenol (1d) and 3,4,5,6-tetrabromo-2-(2′,4′-dibromophenoxy)phenol (2b), were isolated from the Indonesian marine sponge Lamellodysidea herbacea. The structure was confirmed using ¹³C chemical shift average deviation and was compared to the predicted structures and recorded chemical shifts in previous studies. We found a wide range of bioactivities from the organic crude extract, such as (1) a strong deterrence against the generalist pufferfish Canthigaster solandri, (2) potent inhibition against environmental and human pathogenic bacterial and fungal strains, and (3) the inhibition of the Hepatitis C Virus (HCV). The addition of a bromine atom into the A-ring of compound 2b resulted in higher fish feeding deterrence compared to compound 1d. On the contrary, compound 2b showed only more potent inhibition against the Gram-negative bacteria Rhodotorula glutinis (MIC 2.1 μg/mL), while compound 1d showed more powerful inhibition against the other human pathogenic bacteria and fungi. The first report of a chemical defense by compounds 1d and 2b against fish feeding and environmental relevant bacteria, especially pathogenic bacteria, might be one reason for the widespread occurrence of the shallow water sponge Lamellodysidea herbacea in Indonesia and the Indo-Pacific.