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Eleven strains of an entomopathogenic fungus, isolated and identified as Ophiocordyceps sobolifera, were screened for activity against 5 strains of Gram-negative and 5 strains of Gram-positive bacteria. Four of the isolates, Cod-KK1634, Cod-KK1643, Cod-KS1601, and Cod-SN1626, had activity against the test strains of Grampositive bacteria. Of these 4 extracts, the Cod-KK1643 extract had the lowest minimum inhibitory and bactericidal concentrations. The Cod-KK1643 extract exhibited both concentration- and time-dependent bactericidal activity. Moreover, the Cod-KK1643 extract induced morphological alterations in bacterial cells, including decreased cell size, a crushed appearance, and cell lysis. It is surprising to note that the extracts also inhibited MCF-7 cell proliferation, with a half-maximal inhibitory concentration of 47.09 ± 33.64 mg/mL after 72 hours. The extracts also inhibited MCF-7 cell migration, with the lowest percentage of relative closure achieved with Cod-KK1643. These findings represent what is to our knowledge the first information on the activities of O. sobolifera mycelial extracts against bacteria and the human breast cancer MCF-7 cell line.

The entomopathogenic fungus Polycephalomyces nipponicus is known to have activity against human pathogenic bacteria and the malaria pathogen; however, information about its genetic variation is limited. In this study, cicada nymphs infected with entomopathogenic fungi were collected from various locations in the northeast of Thailand. Internal transcribed spacer sequencing was used to identify the fungal pathogen P. nipponicus. A total of 36 isolates of P. nipponicus from 6 provinces were investigated for variations in fungal morphology, nucleoside analog content, and genetics. The results showed that colony morphology varied depending on the strain of the tested fungi, without influence from its geographic origin. A similar finding was observed with regard to the production of nucleoside analog content. Interestingly, the important bioactive compound adenosine was detected in the mycelial extract of all 36 isolates. This indicates that P. nipponicus could possibly be used as a source of potential therapeutic bioactive compounds. In addition, random amplified polymorphic DNA analysis, as supported by the Nei Index and Shannon Index values, showed high genetic variation within and between the populations. These findings represent what is, to our knowledge, the first information on the colony morphology, adenosine analog profile, and genetic variation of P. nipponicus.

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