SNA-077

Bioassay and HPLC-UV guided fractionations of the crude extract of marine-derived Streptomyces sp. SNA-077 have led to the isolation of a red pigment, undecylprodigiosin (1). The chemical structure of undecylprodigiosin (1) was revealed by the interpretation of NMR and mass spectroscopic (MS) data. Further, anti-melanogenic effects of undecylprodigiosin (1) were investigated. First, the melanin contents of undecylprodigiosin (1)-treated B16 cells were evaluated. Furthermore, undecylprodigiosin (1) significantly inhibited the key enzymes involved in melanogenesis, including tyrosinase, tyrosinase related protein-1 (TYRP-1), and dopachrome tautomerase (DCT). The mRNA and protein expression levels of Microphthalmia-associated transcriptian factor (MiTF), a critical transcription factor for tyrosinase gene expression, were also suppressed by undecylprodigiosin (1) treatment in B16 analyses. Collectively, our results suggest for the first time that undecylprodigiosin (1), a potent component isolated from an extract of marine Streptomyces sp. SNA-077, critically exerts the anti-melanogenic ability for melanin synthesis.

Whole-genome sequencing and analysis of Streptomyces strains producing multiple antinematode drugs

Background

Nematodes are parasitic animals that cause over 100 billion US dollars loss in agricultural business. The whole-genomes of two Streptomyces strains, Streptomyces spectabilis KCTC9218^T and Streptomyces sp. AN091965, were sequenced. Both strains produce spectinabilin, an antinematode drug. Its secondary metabolism was examined to aid the development of an efficient nematicidal drug-producing host strain.

Results

The whole-genome sequences of S. spectabilis KCTC9218^T and Streptomyces sp. AN091965 were analyzed using PacBio and Illumina sequencing platforms, and assembled using hybrid methodology. The total contig lengths for KCTC9218^T and AN091965 were 9.97 Mb and 9.84 Mb, respectively. A total of 8,374 and 8,054 protein-coding genes, as well as 39 and 45 secondary metabolite biosynthetic gene clusters were identified in KCTC9218^T and AN091965, respectively. 18.4 ± 6.45 mg/L and 213.89 ± 21.30 mg/L of spectinabilin were produced by S. spectabilis KCTC9218^T and Streptomyces sp. AN091965, respectively. Pine wilt disease caused by nematode was successfully prevented by lower concentration of spectinabilin injection than that of abamectin recommended by its manufacturer. Production of multiple antinematode drugs, including spectinabilin, streptorubin B, and undecylprodigiosin was observed in both strains using high-resolution liquid chromatography mass spectrometry (LC–MS) analysis.

Conclusions

Whole-genome sequencing of spectinabilin-producing strains, coupled with bioinformatics and mass spectrometry analyses, revealed the production of multiple nematicidal drugs in the KCTC9218^T and AN091965 strains. Especially, Streptomyces sp. AN091965 showed high production level of spectinabilin, and this study provides crucial information for the development of potential nematicidal drug producers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08847-4.

Butylcycloheptylprodigiosin and undecylprodigiosin are potential photosensitizer candidates for photodynamic cancer therapy

BACKGROUND

Prodiginines are bacterial red polypyrrole pigments and multifaceted secondary metabolites. These agents have anti-proliferative, immunosuppressive, antimicrobial, and anticancer effects. Recent analysis revealed that prodigiosin hypersensitizes Serratia marcescens to gamma radiation. In the present study, we report the cytotoxicity and genotoxicity properties of undecylprodigiosin and butylcycloheptylprodigiosin in the presence and absence of radiation through the MTT and alkaline comet experiments.

METHODS AND RESULTS

Findings demonstrated that undecylprodigiosin was at least a fivefold more cytotoxic at low radiation doses (1 and 3 Gy) on both MCF7 and HDF lines rather than in the absence or high radiation doses (5 Gy) (P value < 0.05). Although butylcycloheptylprodigiosin toxicity on MCF7 and HDF was dose-dependent, it was not influenced by any radiation doses (P value > 0.05). Comet findings confirmed that these compounds' genotoxicity is only dose-dependent. Radiation had no significant effects on DNA damage on any of the cells (P value > 0.05).

CONCLUSIONS

In general, it can be concluded that the prodiginines are cytotoxic agents that act as a double-edged sword, radiosensitizers and radio-protective, respectively at low and high radiation doses in cancer treatment process. As the results they could be used in antitumor therapies very soon.

ALAA-R20 through low-cost induction strategy

Genetic manipulation of the undecylprodigiosin-producing strains and engineered culture medium approaches were applied as the most economical induction strategy for improving production. The hyper-producing recombinant strain ALAA-R20 was obtained after applying protoplast fusion strategy between the potent producer marine endophytic strains Streptomyces sp. ESRAA-10 (P1) and Streptomyces sp. ESRAA-31 (P2) of Dendronephthya hemprichi. Recombinant strain ALAA-R20 produced undecylprodigiosin yield higher than its parental strains ESRAA-10 and ESRAA-31 by 82.45% and 105.52% under submerged fermentation using modified R2YE medium. In order to reduce the costs of producing undecylprodigiosin, a solid-state fermentation (SSF) was applied. Scaled-up of optimized SSF parameters consisting of groundnut oil cake (GOC) sized to 3 mm, initial moisture content 80% with a mixture of dairy mill and fruit processing wastewaters (1:1), pH 7.0, inoculum size equal to 3 × 10⁵ spores/g dry substrate (gds), incubation temperature 30 °C, and 7-day incubation period yielded the highest yield of 181.78 mg/gds of undecylprodigiosin by the recombinant strain Streptomyces sp. ALAA-R20. Extraction and purification of the pigment using the chromatographic techniques as well as mass spectral analysis exhibited maximum absorbance at 539 nm which is physiological property of the undecylprodigiosin. Undecylprodigiosin was stable over a wide temperature ranged from - 20 to 35 °C even after storage for 6 months. The maximum yield and stability of pigment was obtained at the acidic pH (acidified methanol, pH 4.0). Undecylprodigiosin obtained from the recombinant strain Streptomyces sp. ALAA-R20 demonstrated strong antimicrobial activity against all multidrug-resistant bacterial and fungal strains tested with minimum inhibitory, minimum bactericidal, and minimum fungicidal concentrations ranged between 0.5 and 4.0, 0.5 to 4.0, and 1.0 to 8.0 μg/mL, respectively. It also showed complete inhibition of cancer cells; HCT-116, HepG-2, MCF-7 and A-549 at 5, 8, 4, and 7 μM with IC₅₀ equal to 2.0, 4.7, 1.2, and 2.8 μM, respectively.

The metabolic switch can be activated in a recombinant strain of Streptomyces lividans by a low oxygen transfer rate in shake flasks

Background

In Streptomyces, understanding the switch from primary to secondary metabolism is important for maximizing the production of secondary metabolites such as antibiotics, as well as for optimizing recombinant glycoprotein production. Differences in Streptomyces lividans bacterial aggregation as well as recombinant glycoprotein production and O-mannosylation have been reported due to modifications in the shake flask design. We hypothetized that such differences are related to the metabolic switch that occurs under oxygen-limiting conditions in the cultures.

Results

Shake flask design was found to affect undecylprodigiosin (RED, a marker of secondary metabolism) production; the RED yield was 12 and 385 times greater in conventional normal Erlenmeyer flasks (NF) than in baffled flasks (BF) and coiled flasks (CF), respectively. In addition, oxygen transfer rates (OTR) and carbon dioxide transfer rates were almost 15 times greater in cultures in CF and BF as compared with those in NF. Based on these data, we obtained respiration quotients (RQ) consistent with aerobic metabolism for CF and BF, but an RQ suggestive of anaerobic metabolism for NF.

Conclusion

Although the metabolic switch is usually related to limitations in phosphate and nitrogen in Streptomyces sp., our results reveal that it can also be activated by low OTR, dramatically affecting recombinant glycoprotein production and O-mannosylation and increasing RED synthesis in the process.

Electronic supplementary material

The online version of this article (10.1186/s12934-018-1035-3) contains supplementary material, which is available to authorized users.

Biological effects of bacterial pigment undecylprodigiosin on human blood cells treated with atmospheric gas plasma in vitro

It is known that some bacterial species are more resilient to different kinds of irradiation due to the naturally developed protective mechanisms and compounds such as pigments. On the other hand, reasoned tissue engineering using plasma remains a critical task and requires very precise control of plasma parameters in order to mitigate its potential detrimental effects. Here we isolated a natural protective agent, microbially produced undecylprodigiosin ((5'Z)-4'-methoxy-5'-[(5-undecyl-1H-pyrrol-2-yl)methylene]-1H,5'H-2,2'-bipyrrole), and investigated its effects on human blood cells independently and in combination with plasma. Two approaches were applied; the first, undecylprodigiosin (UP pigment) was added to the blood cultures, which then were exposed to plasma (pre-treatment); and the second- the blood cultures were exposed to plasma and then treated with pigment (post-treatment). The interactions of plasma and UP pigment with blood cells were investigated by conducting a series of biological tests providing the information regarding their genotoxicity, cytotoxicity and redox modulating activities. The exposure of cells to plasma induced oxidative stress as well as certain genotoxic and cytotoxic effects seen as elevated micronuclei incidence, decreased cell proliferation and enhanced apoptosis. In blood cultures treated with UP pigment alone, we found that both cytotoxic and protective effects could be induced depending on the concentration used. The highest UP pigment concentration increased lipid peroxidation and the incidence of micronuclei by more than 70% with maximal suppression of cell proliferation. On the contrary, we found that the lowest UP pigment concentration displayed protective effects. In combined treatments with plasma and UP pigment, we found that UP pigment could provide spatial shielding to plasma exposure. In the pre-treatment approach, the incidence of micronuclei was reduced by 35.52% compared to control while malondialdehyde level decreased by 36% indicating a significant mitigation of membrane damage induced by plasma. These results open perspectives for utilizing UP pigment for protection against overexposures in the field of plasma medicine.

Medium engineering for enhanced production of undecylprodigiosin antibiotic in Streptomyces coelicolor using oil palm biomass hydrolysate as a carbon source

In this study, a biosugar obtained from empty fruit bunch (EFB) of oil palm by hot water treatment and subsequent enzymatic saccharification was used for undecylprodigiosin production, using Streptomyces coelicolor. Furfural is a major inhibitor present in EFB hydrolysate (EFBH), having a minimum inhibitory concentration (MIC) of 1.9mM, and it reduces utilization of glucose (27%), xylose (59%), inhibits mycelium formation, and affects antibiotic production. Interestingly, furfural was found to be a good activator of undecylprodigiosin production in S. coelicolor, which enhanced undecylprodigiosin production by up to 52%. Optimization by mixture analysis resulted in a synthetic medium containing glucose:furfural:ACN:DMSO (1%, 2mM, 0.2% and 0.3%, respectively). Finally, S. coelicolor was cultured in a fermenter in minimal medium with EFBH as a carbon source and addition of the components described above. This yielded 4.2μg/mgdcw undecylprodigiosin, which was 3.2-fold higher compared to that in un-optimized medium.