Project description:Rhagadiolus stellatus Gaertn., a Mediterranean member of the Cichorieae tribe of the Asteraceae family used as a food plant, was analyzed for its spectrum of phenolic compounds. Kaempferol 3-O-?-glucoside 1, kaempferol 3-O-?-rutinoside (nicotiflorin) 2, quercetin 3-O-?-glucoside 3, and luteolin 4 were isolated from the n-butanol layer of a methanolic extract of whole plants of Rh. stellatus of Spanish origin by repeated Sephadex LH-20 column chromatography. Structures were determined based on NMR and MS data as well as by comparison with literature data. Additionally, chlorogenic acid 5 and 3,5-dicaffeoylquinic acid 6 were detected by HPLC/DAD and HPLC/MS. Chemosystematic implications of the presented findings are discussed in comparison with other members of the Cichorieae tribe.
Project description:In this study, the mitogenome of artillery fungus, Sphaerobolus stellatus, was assembled and compared with other Basidiomycota mitogenomes. The Sphaerobolus stellatus mitogenome was composed of circular DNA molecules, with a total size of 152,722 bp. Accumulation of intergenic and intronic sequences contributed to the Sphaerobolus stellatus mitogenome becoming the fourth largest mitogenome among Basidiomycota. We detected large-scale gene rearrangements in Basidiomycota mitogenomes, and the Sphaerobolus stellatus mitogenome contains a unique gene order. The quantity and position classes of intron varied between 75 Basidiomycota species we tested, indicating frequent intron loss/gain events occurred in the evolution of Basidiomycota. A novel intron position classes (P1281) was detected in the Sphaerobolus stellatus mitogenome, without any homologous introns from other Basidiomycota species. A pair of fragments with a total length of 9.12 kb in both the nuclear and mitochondrial genomes of Sphaerobolus stellatus was detected, indicating possible gene transferring events. Phylogenetic analysis based on the combined mitochondrial gene set obtained well-supported tree topologies (Bayesian posterior probabilities ? 0.99; bootstrap values ?98). This study served as the first report on the mitogenome from the order Geastrales, which will promote the understanding of the phylogeny, population genetics, and evolution of the artillery fungus, Sphaerobolus stellatus.
Project description:The identification and 3D structural characterization of a homolog of the (R)-selective transaminase (RTA) from Aspergillus terreus (AtRTA), from the thermotolerant fungus Thermomyces stellatus (TsRTA) is here reported. The thermostability of TsRTA (40% retained activity after 7 days at 40°C) was initially attributed to its tetrameric form in solution, however subsequent studies of AtRTA revealed it also exists predominantly as a tetramer yet, at 40°C, it is inactivated within 48 h. The engineering of a cysteine residue to promote disulfide bond formation across the dimer-dimer interface stabilized both enzymes, with TsRTA_G205C retaining almost full activity after incubation at 50°C for 7 days. Thus, the role of this mutation was elucidated and the importance of stabilizing the tetramer for overall stability of RTAs is highlighted. TsRTA accepts the common amine donors (R)-methylbenzylamine, isopropylamine, and d-alanine as well as aromatic and aliphatic ketones and aldehydes.