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UPV Theses and Dissertations

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    Antimicrobial activity of macrofungal basidiomycetous mycelia against Vibrio spp.
    Bagacay, Jann Felnesh Exe V. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2023-06)
    Aquaculture is vital for global food security, producing 50% of the world’s fish. However, infectious diseases caused by fish pathogens like Vibrio species can lead to significant production losses. To address this issue, antimicrobial agents are commonly used. Macrofungal fruiting bodies and mycelia produce bioactive compounds with antimicrobial properties. This study aims to: (a) assess antimicrobial activity in isolated macrofungal samples against the fish bacterial pathogens Vibrio parahaemolyticus and Vibrio cholerae, (b) compare two methods (agar plug and crude extracts) for antimicrobial activity, (c) determine the minimum inhibitory concentration (MIC) using agar well diffusion and the agar plug methods, and (d) identify the macrofungal isolate with the highest antimicrobial activity. Ten morphospecies were collected from the University of the Philippines Visayas Miagao Campus. The samples were evaluated using the agar plug and agar well diffusion methods. The results showed antimicrobial activity against Vibrio cholerae and Vibrio parahaemolyticus. The activity index ranged from 0 to 0.83 and 0.22 to 0.78 for agar wells, and 0 to 1.00 and 0.70 to 1.30 for agar plugs, against V cholerae and V. parahaemolyticus, respectively. Termitomyces globulus and Trametes sp. 1 exhibited the highest activity indices using the agar plug and agar well diffusion methods, respectively. Statistical analysis confirmed significant differences in antimicrobial activity against both test organisms. These findings demonstrate the potential of macrofungi as a valuable source of antimicrobial compounds for controlling fish pathogens in aquaculture. Further research could lead to the identification and utilization of these compounds to minimize production losses and improve disease management in aquaculture.
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    Endophytic fungi from Halimeda macroloba and Sargassum sp.in Nueva Valencia Nueva Valencia, Guimaras, Philippines
    Alemania, Darlene Kris V. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Endophytic fungi of marine algae in the Philippines have not been widely explored despite the fact that marine fungi associated with algae are the second most diverse. This study aimed to conduct a preliminary investigation on the occurrence of endophytic fungi from Halimeda macroloba and Sargassum sp. In this study fungal endophytes were isolated from Halimeda macroloba and Sargassum sp. collected from Nueva Valencia, Guimaras. Broad-leaf macroalagal samples were surface sterilized and cultured on PDA seawater media at 37°C. Isolated fungal endophytes were identified through colony and microscopic characteristics. Twenty one distinct endophytic fungi were isolated, 17 of which were identified up to the genus level with the most endophytes belonging to the genus Aspergillus. Fungal endophytes obtained were mostly ascomycetes specifically Aspergillus sp., one hyphomycete and three unidentified fungi with sterile mycelia were present. The brown algae, Sargassum sp., had a higher diversity compared to the green algae Halimeda macroloba in spite of having a lower isolation frequency. In terms of similarity, the two algal hosts had a low index of similarity with J= 10%. This study contributes to the growing data regarding diversity and abundance of fungal endophyte species from marine macroalgae in the Philippines. This is the first study conducted on fungal endophyte assemblages of algae species in Western Visayas.