Microfungi diversity isolation from sandy soil of Acapulco touristic beaches

Authors: GONZALEZ, MARIA - Autonomous National University Of Mexico; HANLIN, RICHARD - University Of Georgia; Glenn, Anthony - Tony

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Microscopic fungi diversity in marine sandy soil habitats is associated with key functions of beach ecosystems. There are few reports on their presence in Mexican beaches. Although standard methods to obtain the fungi from soil samples are established, the aim of this pilot study was to test the plating technique using two culture media with a mix of three antibiotics at five different concentrations. The results will permit us to apply a methodology specifically designed for a further project to study the arenicolous fungi from this unique place. Eight beaches in Acapulco de Juárez, State of Guerrero, México, located on the littoral of the Pacific Ocean were studied: Caleta, Tlacopanocha, Hamacas, Hornos, Hornitos, Calinda, Icacos and La Palapa. At intertidal zone of each beach, a sample of sandy soil (200 g) from the surface layer was collected in a Zip lock bag and transported to the laboratory to be processed within 24 h. The soil plating method was applied for qualitative and quantitative isolation of sandy beach mycobiota. One gram of wet sandy soil was put onto a sterile Petri dish and immediately covered with autoclaved Mycosel agar previously cooled to 45 °C. As some fungal development may be influenced or inhibited by the ingredients and antibiotics of this culture medium, V-8 vegetable juice agar, supplemented with different concentrations de penicillin G/streptomycin sulfate/chloramphenicol also was prepared and inoculated using the same procedure. The media with the sandy soil was shaken gently and solidified. Ten plates of each media were prepared, including positive and negative controls, for each single beach. After 7, 14, 21, 28 d of incubation at 25 °C, the dishes were examined. The colonies obtained were identified based on their macro- and micro-morphological characteristics and their occurrence indicated by: 1) number of fungi obtained in pure culture, 2) number of different colonies divided by the number of Petri dishes prepared, 3) frequency of isolation of fungi (number of fungal colony forming units of a given species divided by the total number of fungi × 100%). Results indicated that the sand beach community is relatively species rich, with representatives of sewage habitats. The optimal concentration of antibiotics to inhibit the growth of bacteria was several times higher than the values established in the literature for the isolation of fungi from sewage. Adequate concentrations of antibiotics will control the growth of rapidly growing fungi and will permit the isolation of other species with slower growth. A total of 46 fungi were isolated. Acremonium, Aspergillus, Cladosporium, Fusarium were the common genera and Gymnascella, Malbranchea, Mucor, the less common. Most of the genera belonged to the Ascomycota, with fewer to the Mucorales. The Hornos Beach has the highest species richness and the lowest in the adjacent Hornitos Beach. The mycobiota obtained using the two media showed a 98% of dissimilarity. Of the total number of Petri dishes inoculated, 87% were positive for fungal growth.