ABSTRACT
Endophytic fungi are promising sources for the production of podophyllotoxin-an important anticancer compound, replacing depleted medical plants. In this study, the endophytes associated with Dysosma difformis-an ethnomedicinal plant species were isolated to explore novel sources of podophyllotoxin. Fifty-three endophytic fungi were isolated and identified by morphological observation and ITS-based rDNA sequencing, assigning them to 27 genera in 3 divisions. Fusarium was found the most prevalent genus with a colonization frequency of 11.11%, followed by Trametes (9.26%) and Penicillium (7.41%). Phylogenetic trees were constructed for the endophytic fungi community in two collection sites, Ha Giang and Lai Chau, revealing the adaptation of the species to the specific tissues and habitats. Cytotoxic activity of endophytic fungal extracts was investigated on cancer cell lines such as SK-LU-1, HL-60, and HepG2, demonstrating strong anti-cancer activity of six isolates belonging to Penicillium, Trametes, Purpureocillium, Aspergillus, and Ganoderma with IC50 value of lower than 10 µg/mL. The presence of podophyllotoxin was indicated in Penicillium, Trametes, Aspergillus and for the first time in Purpureocillium and Ganoderma via high-performance liquid chromatography, which implied them as a potential source of this anti-cancer compound.
ABSTRACT
Huperzine A (HupA), a natural Lycopodium alkaloid derived from Huperzia serrata (Thunb. ex Murray) Trev. plants, is a highly active acetylcholinesterase inhibitor and a key compound used for treating Alzheimer's disease (AD). Recently, HupA has been reported in various endophytic fungi isolated from H. serrata. In the present study, 153 endophytic fungi were isolated from healthy tissues of H. serrata collected from natural populations in Lam Dong province of Central Vietnam. The endophytic fungi were identified based on morphological characteristics and Internal Transcribed Spacer sequences. Among them, 34 strains were classified into seven genera belonging to Ascomycota, including Alternaria, Fusarium, Trichoderma, Penicillium, Paecilomyces, and Phoma, and eight strains belonging to the genus Mucor (Zygomycota). The other strains remained unidentified. According to the results of thin-layer chromatography and high-performance liquid chromatography, only one of the 153 strains, Penicillium sp. LDL4.4, could produce HupA, with a yield 1.38 mg l-1 (168.9 µg g-1 dried mycelium) when cultured in potato dextrose broth, which was considerably higher than that of other reported endophytic fungi. Such a fungus is a promising candidate and alternative to presently available HupA production techniques for treating AD and preventing further memory decline.
Subject(s)
Alkaloids/biosynthesis , Ascomycota/isolation & purification , Cholinesterase Inhibitors/pharmacology , Endophytes/isolation & purification , Huperzia/microbiology , Mucor/isolation & purification , Acetylcholinesterase/drug effects , Alkaloids/isolation & purification , Alkaloids/pharmacology , Cholinesterase Inhibitors/isolation & purification , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , DNA, Fungal/genetics , DNA, Ribosomal Spacer/genetics , Endophytes/chemistry , Endophytes/classification , Endophytes/growth & development , Huperzia/metabolism , Mycological Typing Techniques , Phylogeny , Sesquiterpenes/isolation & purification , Sesquiterpenes/pharmacology , Species Specificity , VietnamABSTRACT
Based on a total of 6,295,650 sequences from the V3 and V4 regions (16S ribosomal RNA), the composition of the microorganism communities in the water of three Litopenaeus vannamei (Decapoda, Whiteleg shrimp; Soc Trang, Vietnam) ponds were identified. Pseudomonas (10-20.29%), Methylophilus (13.26-24.28%), and Flavobacterium (2.6-19.29%) were the most abundant genera. The total ammonia (TAN) concentration (p = 0.025) and temperature (p = 0.015) were significantly correlated with the relative abundance of Pseudomonas in two bacterial communities (ST1, ST4), whereas the predictive functions of microorganism communities based on 16S rRNA gene data was estimated using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUST), which showed that nitrogen metabolism was significantly negatively correlated (p = 0.049) with TAN concentration. The abundance of Pseudomonas and nitrogen metabolism increased with a decrease in TAN concentration. The correlation between TAN concentration and the abundance of Pseudomonas was followed by the isolation, and heterotrophic nitrifying performance analysis was used to confirm our findings. Six Pseudomonas strains capable of heterotrophic nitrification were isolated from the three water samples and showed a complete reduction of 100 mg/L NH4Cl during a 96-h cultivation. These results indicate the potential of applying Pseudomonas in shrimp ponds for water treatment.
