Genetic and Histopathological Alterations in Caco-2 and HuH-7 Cells Treated with Secondary Metabolites of Marine fungi

Metabolic profiling, antimicrobial, anticancer, and in vitro and in silico immunomodulatory investigation of Aspergillus niger OR730979 isolated from the Western Desert, Egypt

Ten fungal species were isolated from soil in the Western Desert and Wadi El-Natron in Egypt. All fungal isolates were morphologically recognized down to the species level. Methanol extracts of fungal mycelia and ethyl acetate extracts of culture filtrate from the isolated fungi were evaluated for antimicrobial activity against six pathogenic bacteria and one pathogenic yeast (Candida albicans ATCC20231). Only ethyl acetate extracts of Fusarium circinatum, Aspergillus niger, and Aspergillus terreus culture filtrates showed significant antimicrobial activity against the majority of the investigated pathogens. The culture filtrate extract of Aspergillus niger exhibited notable cytotoxicity towards the breast cancer (MCF-7) cell line, with the lowest detected IC50 recorded at 8 μg/μl. Whereas Fusarium circinatum and Aspergillus terreus had IC50s of 15.91 μg/μl and 18 μg/μl, respectively. A gas chromatography-mass spectroscopy (GC-MS) investigation of A. niger's potent extract revealed 23 compounds with different biological activities. Glycidyleoleate was found to be the main extract component. Aspergillus niger extract was chosen to study its possible cytotoxic mechanism. The extract was found to induce apoptosis and cell cycle arrest at the < 2n stage. Despite a significant increase in caspases 8 and 9, the production levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) have shown a significant decrease. The high interaction of glycidyleoleate against the studied cytokines' binding receptors was demonstrated via docking studies. In conclusion, the available data revealed that the culture filtrate extract of A. niger possesses promising antimicrobial, cytotoxic, and immunomodulatory properties.

Hindering the biofilm of microbial pathogens and cancer cell lines development using silver nanoparticles synthesized by epidermal mucus proteins from Clarias gariepinus

Scientists know very little about the mechanisms underlying fish skin mucus, despite the fact that it is a component of the immune system. Fish skin mucus is an important component of defence against invasive infections. Recently, Fish skin and its mucus are gaining interest among immunologists. Characterization was done on the obtained silver nanoparticles Ag combined with Clarias gariepinus catfish epidermal mucus proteins (EMP-Ag-NPs) through UV-vis, FTIR, XRD, TEM, and SEM. Ag-NPs ranged in size from 4 to 20 nm, spherical in form and the angles were 38.10°, 44.20°, 64.40°, and 77.20°, Where wavelength change after formation of EMP-Ag-NPs as indicate of dark brown, the broad band recorded at wavelength at 391 nm. Additionally, the antimicrobial, antibiofilm and anticancer activities of EMP-Ag-NPs was assessed. The present results demonstrate high activity against unicellular fungi C. albicans, followed by E. faecalis. Antibiofilm results showed strong activity against both S. aureus and P. aeruginosa pathogens in a dose-dependent manner, without affecting planktonic cell growth. Also, cytotoxicity effect was investigated against normal cells (Vero), breast cancer cells (Mcf7) and hepatic carcinoma (HepG2) cell lines at concentrations (200-6.25 µg/mL) and current results showed highly anticancer effect of Ag-NPs at concentrations 100, 5 and 25 µg/mL exhibited rounding, shrinkage, deformation and granulation of Mcf7 and HepG2 with IC50 19.34 and 31.16 µg/mL respectively while Vero cells appeared rounded at concentration 50 µg/mL and normal shape at concentration 25, 12.5 and 6.25 µg/ml with IC50 35.85 µg/mL. This study evidence the potential efficacy of biologically generated Ag-NPs as a substitute medicinal agent against harmful microorganisms. Furthermore, it highlights their inhibitory effect on cancer cell lines.

Marine-Derived Leads as Anticancer Candidates by Disrupting Hypoxic Signaling through Hypoxia-Inducible Factors Inhibition

The inadequate vascularization seen in fast-growing solid tumors gives rise to hypoxic areas, fostering specific changes in gene expression that bolster tumor cell survival and metastasis, ultimately leading to unfavorable clinical prognoses across different cancer types. Hypoxia-inducible factors (HIF-1 and HIF-2) emerge as druggable pivotal players orchestrating tumor metastasis and angiogenesis, thus positioning them as prime targets for cancer treatment. A range of HIF inhibitors, notably natural compounds originating from marine organisms, exhibit encouraging anticancer properties, underscoring their significance as promising therapeutic options. Bioprospection of the marine environment is now a well-settled approach to the discovery and development of anticancer agents that might have their medicinal chemistry developed into clinical candidates. However, despite the massive increase in the number of marine natural products classified as 'anticancer leads,' most of which correspond to general cytotoxic agents, and only a few have been characterized regarding their molecular targets and mechanisms of action. The current review presents a critical analysis of inhibitors of HIF-1 and HIF-2 and hypoxia-selective compounds that have been sourced from marine organisms and that might act as new chemotherapeutic candidates or serve as templates for the development of structurally similar derivatives with improved anticancer efficacy.

Aspergillus niger CJ6 extract with antimicrobial potential promotes in-vitro cytotoxicity and induced apoptosis against MIA PaCa-2 cell line

Nowadays, the increased number of multidrug-resistant strains among pathogens is a severe public health concern and cancer is posing a great threat for humans. These problems should be tackled with the development of novel and broad-spectrum antimicrobials from microbial origin. During the present study, the bioactive secondary metabolites from Aspergillus niger CJ6 were extracted, characterized; their biological properties were evaluated by subjecting them for antimicrobial, antifungal and anticancer activities. The potent isolate Aspergillus niger CJ6 with nucleotide sequence of 959 base pairs showed antagonistic activity against fungal pathogens in dual culture. The chemical profiling of crude ethyl acetate extract indicated the presence of various bioactive molecules belonging to phenolic, hydrocarbons, and phthalate derivative classes. In antimicrobial activity, the crude extract displayed increasing activity with increased concentration; the highest activity observed against Shigella flexneri with 15 ± 1.0, 19 ± 0.5, 20 ± 1.0 and 24 ± 1.0 mm zones of inhibition at 25, 50, 75 and 100 μl concentrations. The MTT assay illustrated deformed cells of MIA PaCa-2 cell line in in-vitro cytotoxic activity; outflow of cell matrix and membrane rupture; the IC₅₀ of 90.78 μg/ml suggested moderate potential of extract to prevent cancer cell growth. The apoptosis/necrosis study by flow cytometer exhibited 8.98 ± 0.85% early and 73 ± 0.7% of late apoptotic population with 3.8 ± 1.1% necrotic cells; only 14.22 ± 0.6% of healthy cells suggested the increased apoptosis inducing capacity of Aspergillus niger CJ6 crude extract. The outcomes of this study persuade further exploration on the identification, purification and development of novel bioactive agents that could help battle fatal diseases in humans.

Molecular docking and nucleotide sequencing of successive expressed recombinant fungal peroxidase gene in E.coli

Background

Fungal peroxidases are oxidoreductases that utilize hydrogen peroxide to catalyze lignin biodegradation.

Results

PER-K (peroxidase synthesis codon gene) was transformed from Aspergillus niger strain AN512 deposited in the National Center for Biotechnology Information with the accession number OK323140 to Escherichia coli strain (BL21-T7 with YEp356R recombinant plasmid) via calcium chloride heat-shock method. The impact of four parameters (CaCl₂ concentrations, centrifugation time, shaking speed, growth intensity) on the efficacy of the transformation process was evaluated. Furthermore, peroxidase production after optimization was assessed both qualitatively and quantitatively, as well as SDS-PAGE analysis. The optimum conditions for a successful transformation process were as follows: CaCl₂ concentrations (50 mM), centrifugation time (20 min), shaking speed (200 rpm), and growth optical density (0.45). PCR and gel electrophoresis detect DNA bands with lengths 175, 179, and 211 bps corresponding to UA3, AmpR, and PER-K genes respectively besides partially sequencing the PER-K gene. Pyrogallol/hydrogen peroxide assay confirmed peroxidase production, and the activity of the enzyme was determined to be 3924 U/L. SDS-PAGE analysis also confirms peroxidase production illustrated by the appearance of a single peroxidase protein band after staining with Coomassie blue R-250.

Conclusion

A successful peroxidase-gene (PER-K) transformation from fungi to bacteria was performed correctly. The enzyme activity was screened, and partial sequencing of PER-K gene was analyzed successively. The protein 3D structure was generated via in silico homology modeling, and determination of binding sites and biological annotations of the constructed protein were carried out via COACH and COFACTOR based on the I-TASSER structure prediction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00377-6.

Secondary Metabolites of Actinomycetales as Potent Quorum Sensing Inhibitors Targeting Gram-Positive Pathogens: In Vitro and In Silico Study

Anti-virulence agents are non-bacteriostatic and non-bactericidal emerging therapeutic options which hamper the production of virulence factors in pathogenic flora. In Staphylococcus aureus and Enterococcus faecalis, regulation of virulence genes’ expression occurs through the cyclic peptide-mediated accessory gene regulator (agr) and its ortholog fsr quorum sensing systems, respectively. In the present study, we screened a set of 54 actinomycetales secondary metabolites as novel anti-virulence compounds targeting quorum sensing system of the Gram-positive bacteria. The results indicated that four compounds, Phenalinolactones A–D, BU–4664LMe, 4,5-dehydrogeldamycin, and Questinomycin A, potentially inhibit the agr quorum sensing system and hemolytic activity of S. aureus. On the other hand, Decatromicin A and B, Okilactomycin, Rishirilide A, Abyssomicin I, and Rebeccamycin selectively blocked the fsr quorum sensing system and the gelatinase production in E. faecalis at sub-lethal concentrations. Interestingly, Synerazol uniquely showed the capability to inhibit both fsr and agr quorum sensing systems. Further, in silico molecular docking studies were performed which provided closer insights into the mode of action of these compounds and proposed that the inhibitory activity of these compounds could be attributed to their potential ability to bind to the ATP-active site of S. aureus AgrA. Taken together, our study highlights the potential of actinomycetales secondary metabolites with diverse structures as anti-virulence quorum sensing inhibitors.