Isolation of the Entomopathogenic Fungal Strain Cod-MK1201 from a Cicada Nymph and Assessment of Its Antibacterial Activities.
The entomopathogenic fungus Cod-MK1201 was isolated from a dead cicada nymph. Three regions of ribosomal nuclear DNA, the internal transcribed spacers of nuclear ribosomal DNA repeats (ITS), the partial small subunit of rDNA (nrSSU) , and the partial large subunit of rDNA (nrLSU), and two protein-coding regions, the elongation factor 1α (EF-1α), and the largest subunit of the RNA polymerase II (rpb1) gene, were sequenced and used for fungal identification. The phylogenetic analysis of the ITS and the combined data set of the five genes indicated that the fungal isolate Cod-MK1201 is a new strain of Cordyceps sp. that is closely related to Cordyceps nipponica and C. kanzashiana. Crude extracts of mycelium-cultured Cod-MK1201 were obtained using distilled water and 50% (v/v) ethanol, and the antibacterial activity of each was determined. Both extracts had activity against Gram-positive and Gram-negative bacteria, but the ethanol extract was the more potent of the two. The antibacterial activity of the protein fractions of these extracts was also determined. The protein fraction from the ethanol extract was more antibacterial than the protein fraction from the aqueous extract. Three antibacterial constituents including adenosine, the total phenolic content (TPC), and the total flavonoid content (TFC) was also determined. The results showed that the adenosine content, the TPC, and the TFC of the ethanol extract were more active than those of the aqueous extract. Moreover, synergism was detected between these antibacterial constituents. In conclusion, the entomopathogenic fungal isolate Cod-MK1201 represents a natural source of antibacterial agents.
Microbiology Group, Faculty of Medicine, Muang District, Mahasarakham University, Thailand.
Kusavadee
K
Sangdee
Department of Biology, Faculty of Science, Mahasarakham University, Kantarawichai District, Thailand.
Woranan
W
Nakbanpote
Department of Biology, Faculty of Science, Mahasarakham University, Kantarawichai District, Thailand.
Aphidech
A
Sangdee
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D032661:Cordyceps / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D006430:Hemiptera / Q000382:microbiology*; D008969:Molecular Sequence Data; D025282:Mycelium / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D009758:Nymph / Q000382:microbiology; D010802:Phylogeny
D000900:Anti-Bacterial Agents; D004271:DNA, Fungal; D004275:DNA, Ribosomal