INVESTIGATION OF PRESENCE OF ENDOFUNGAL BACTERIA IN Rhizopus spp. ISOLATED FROM THE DIFFERENT SOURCES ON MARKET
Project no. 459 · Status: Kapanmış · 2017
Summary
Rhizopus species are opportunistic pathogens and cause infections which lead to deaths in individuals with a weakened immune system. When the infection occurs, Rhizopus species produce a variety of enzymes, proteins and by-products with pathogenic potential.Mycotoxins are fungicidal compounds that affect plant, animal and human health negatively through infections and food deterioration. In previous studies, it was known that mycotoxins were produced only by the fungi. However, in recent studies, it has been observed that mycotoxins are produced by endosymbiotic bacteria living in fungi. Rhizopus species may contain endofungal bacteria in hyphae. Some strains of R. microsporus, a filamentous fungus belonging to Zygomycetes, have been detected to have symbiotic relationship with bacteria. Rhizopus species may contain endofungal bacteria in hyphae. Some strains of R. microsporus, a filamentous fungus belonging to Zygomycetes, have been detected to have symbiotic relationship with bacteria. If endofungal bacteria are released from fungal mycelium, sepsis or more serious problems can occur. Therefore, identification of the presence of an opportunistic pathogenic bacterium in frequently consumed food samples in everyday life is of great importance. Therefore, in the present study,we aimed to investigate the presence of endofungal bacteria in Rhizopus species isolated from different food samples. In the present study, convenience foods produced by various companies offered for sale were obtained from different markets and used. For the isolation of Rhizopus from different food sources, the dilution-based technique was used. After the incubation process performed in appropriate conditions, the presence of endofungal bacteria in the isolated Rhizopus strains was investigated. For this purpose, Rhizopus strains were incubated in malt extract broth in a shaking incubator. Some of the fungus pellets formed after incubation were exposed to XIV mechanical fragmentation. Then, the suspension containing antifungal fungal pellet exposed to mechanical fragmentation was inoculated into the antifungal-containing medium and incubated for 24-48 hours at 30°C. Following the incubation, samples were taken from the petri dishes in which bacterial growth was observed. The samples then were subjected to simple staining and examined under a microscope. Rhizopus strains containing the endofungal bacteria were identified through phenotypic and genotypic methods. They were also identified in endofungal bacteria genotypically isolated from fungal hyphae. In order to prove the presence of endosymbiont in fungal hyphae, live / dead staining was conducted. In the present study, 51 Rhizopus isolates were isolated. Of them, 14 bacterial endosymbiont were isolated. Very few endofungal bacteria species have been identified so far. According to the our results, we found that 11 Serratia marcescens, 1 Pseudomonas fluorescens and 2 Klebsiella pneumoniae were detected in fungal hyphae. For the first time, Pseudomonas fluorescens and Klebsiella pneumoniae were identified as endofungal. These species are important because they are opportunistic pathogenic and very dangerous for human health. So, it is important for human health not only presence of the fungi but also presence of the endofungal bacteria in food samples. Our work is important because it draws attention to the presence of a endofungal bacterium in food samples. Because there is a danger releasing of the bacterium from the fungal mycelium, it is likely to face sepsis or more serious problems. In our study we isolated endofungal bacteria the first time in Turkey.