Time-kill profiles and cell-surface morphological effects of crude Polycephalomyces nipponicus Cod-MK1201 mycelial extract against antibiotic-sensitive and -resistant Staphylococcus aureus

Purpose: To examine the effect of crude Polycephalomyces nipponicus  Cod-MK1201 mycelial extract on the viability and cell surface morphology of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).Methods: Time-kill assays were conducted by incubating test bacteria with the extract and sampling at selected time points within a 24 h period. The effects of the extract on MSSA and MRSA ultrastructure were determined using a scanning electron microscope (SEM).Results: Time-kill assay data indicate a bactericidal effect against both strains of staphylococci. The extracts were rapidly bactericidal at concentrations of 1 x MIC and 2 x MIC, achieving complete elimination of the test bacterial strains within 2 h. SEM micrographs of S. aureus taken after treatment with various concentrations of the extract revealed extensive morphological alterations to the cell surface of both MSSA and MRSA.Conclusion: The results confirm the antibacterial activity of P. nipponicus Cod-MK1201 mycelial extract. Further research may allow this to be developed as an alternative therapy to alleviate S. aureus infection.Keywords: Antibacterial activity, Polycephalomyces nipponicus, Staphylococcus aureus, Time-kill assay, Cell surface morpholog

Effects of mycelial extract and crude protein of the medicinal mushroom, Ophiocordyceps sobolifera, on the pathogenic fungus, Candida albicans

Purpose: To investigate the antifungal effect of the mycelial extracts and crude proteins of the medicinal mushroom, Ophiocordyceps sobolifera on Candida albicans.Methods: The antifungal activities of the mycelial extracts and crude proteins of seven strains of the entomopathogenic fungus, Ophiocordyceps sobolifera, were screened against Candida albicans strain NCYC854 using an agar well diffusion method. Minimum inhibitory concentrations (MIC) and minimum fungicidal concentration (MFC) were determined using broth microdilution method. The kinetics of fungal death was elucidated via time-kill assays, and while ultrastructural alteration changes to fungal cells were investigated by scanning electron microscopy (SEM).Results: The antifungal activities of the mycelial extracts were superior to those of the crude proteins. Among the isolates, Cod-KK1643 exhibited the highest activity with the lowest MIC against the test strains. Therefore, it was chosen for further investigations. The isolate Cod-KK1643 exhibited concentration- and time-dependent fungistatic activity in the time kill assay. However, these activities were absent in the crude protein of the isolate. Moreover, Cod-KK1643 mycelial extract induced morphological alterations in fungal cells, such as decreased cell size, and crushed or cracked appearance. Slight alterations in cell morphology (decreased cell size or crushed appearance) were observed in the crude protein treatment.Conclusion: The mycelial extracts of the fungus, O. sobolifera (especially isolate Cod-KK1643) exert potent antifungal activity against human pathogenic fungus, C. albicans.Keywords: Anti-fungal activity, Candida albicans, Entomopathogenic fungus, Ophiocordyceps sobolifer

Antibacterial and anti-breast cancer cell line activities of Sanghuangporus sp.1 extracts

Purpose: To evaluate the activity of extracts of Sanghuangporus sp.1 fungus against pathogenic bacteria and a breast cancer cell line.Methods: The wild fruiting body and mycelium of Sanghuangporus sp.1 were extracted with water and ethanol by ultrasonication extraction. The activity of the extracts against pathogenic bacteria was determined by agar-well diffusion method while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were obtained by agar-well diffusion and broth macrodilution methods. The cytotoxicity of the extract against human breast cancer cell line MCF-7 was determined by sulforhodamine B assay.Results: Only the ethanol mycelial extract exhibited antibacterial activity. Activity was detected against 6 of the 17 test strains of bacterial pathogen. The MICs and MBCs against these 6 strains were quite low, especially for B. cereus ATCC 11778 (2.5 and 2.5 mg/mL) and S. aureus (MSSA, DMST 2933, 2.5 and 5.0 mg/mL). The ethanol mycelial extract was a more potently cytotoxic against MCF-7 cells than either the aqueous mycelial extract or the ethanol wild fruiting body extract,  inhibiting cell growth at a concentration of 250 μg/mL. The aqueous wild fruiting body extract was inactive against MCF-7 cells when compared with untreated control groups.Conclusion: The ethanol mycelial extract of the medicinal mushroom  Sanghuangporus sp.1, obtained by ultrasonication extraction method, exhibited potent antibacterial and anticancer activity and seems to be a substitute for wild Sanghuangporus sp.Keywords: Antibacterial activity, Anticancer activity, Sanghuangporus sp.1, Mycelia

Investigation of antibacterial and anti-cancer activities of Streptomyces sp SRF1 culture filtrate

Purpose: To evaluate the antibacterial activity and cytotoxic effects of Streptomyces sp. SRF1 culture filtrate extract against breast cancer cell line.Methods: The activity of the extract against Gram-positive and Gram-negative bacteria was initially screened by an agar-well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were measured by broth microdilution method. Time-kill assays were also performed, and extract-induced morphological and ultrastructural changes to bacterial cells were investigated. Sulforhodamine B (SRB) assay was performed to determine the cytotoxicity of the extract against the human breast cancer cell line, MCF-7.Results: Antibacterial activity by the extract was detected against four strains of Gram-positive pathogens including one strain of methicillin-susceptible Staphylococcus aureus (MSSA) and 3 strains of methicillin-resistant Staphylococcus aureus (MRSA) - with low MIC and MBC values. This activity was bactericidal after 6 h exposure. Morphological alterations were detected on the cell surface of both MSSA and MRSA. The extract also inhibited MCF-7 cell growth with half-maximal concentration (IC50) of 211.67 ± 33.95 μg/mL in 72 h.Conclusions: Streptomyces sp. SRF1 culture filtrate extract exhibits potent antibacterial and anticancer activities and thus, represents a potential source of antibacterial and anticancer drugs.Keywords: Antibacterial activity, Anti-breast cancer, Staphylococcus aureus, Streptomyces sp. SRF