Novel umami peptides from two Termitomyces mushrooms and molecular docking to the taste receptor T1R1/T1R3

Wild edible Termitomyces mushrooms are popular in Southwest China and umami is important flavor qualities of edible mushrooms.This study aimed to understand the umami taste of Termitomyces intermedius and Termitomyces aff.bulborhizus.Ten umami peptides from aqueous extracts were separated using a Sephadex G-15 gel filtration chromatography.The intense umami fraction was evaluated by both sensory evaluation and electronic tongue.They were identified as KLNDAQAPK,DSTDEKFLR,VGKGAHLSGEH,MLKKKKLA,SLGFGGPPGY,TVATFSSSTKPDD,AMDDDEADLLLLAM,VEDEDEKPKEK,SPEEKKEEET and PEGADKPNK.Seven peptides,except VEDEDEKPKEK,SPEEKKEEET and PEGADKPNK were selectively synthesized to verify their taste characteristics.All these 10 peptides had umami or salt taste.The 10 peptides were conducted by molecular docking to study their interaction with identified peptides and the umami taste receptor T1R1/T1R3.All these 10 peptides perfectly docked the active residues in the T1R3 subunit.Our results provide theoretical basis for the umami taste and address the umami mechanism of two wild edible Termitomyces mushrooms.

Two novel compounds, ergosterol and ergosta-5,8-dien-3-ol, from Termitomyces heimii Natarajan demonstrate promising antihepatocarcinoma activity

Background:Mushroom-derived components have immense potential to become a safe alternative in identifying lead anti-cancer molecules.Termitomyces heimii Natarajan(T.heimii)is a traditionally used edible mushroom with no previous record of anti-hepatocarcinoma activity.Methods:The anti-proliferative efficacy of the mushroom ethyl acetate extract was screened against a panel of seven cancer cell lines,namely Hep G2,MCF-7,MDA-MB-231,MAD-MB-436,MOLT-4,Reh,and K-562,and against peripheral blood mononuclear cells isolated from normal healthy donors by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay.The impact of the extract on nuclear morphology was examined by 40,6-diamidino-2-phenylindole staining and the apoptotic potential of the extract was evaluated through flow cytometry and Annexin V-PI dual staining,followed by an in vitro scratch assay to elucidate the anti-migratory potential of the extract.The apoptotic and antimigratory effects were further validated using in silico molecular docking with four compounds,ergosterol,ergosta-5,8-dien-3-ol,lanosterol,and eburicol,against two anti-apoptotic proteins,Bcl-2 and Bcl-XL,and two angiogenic receptors,VEGFR-1 and VEGFR-2.Results:The screening data revealed that ethyl acetate extract exhibited remarkable anti-proliferative efficacy against Hep G2 cells,with a half maximal inhibitory concentration(IC50)value of 263.53(8.09)mg/mL,followed by MCF-7 cell lines and showed a negligible effect on peripheral blood mononuclear cells.A clear alteration of the cellular and nuclear morphology was concentration-dependently observed in Hep G2 cells.The extract induced robust apoptosis and a significant concentrationdependent increase in the scratch area.The results of in silico docking revealed that compared to standard drug sunitinib,both ergosterol and ergosta-5,8-dien-3-ol displayed lower binding energy,and satisfactory drugability and absorption,distribution,metabolism,excretion,and toxicity properties.Conclusions:T.heimii is a potential source for isolating lead anticancer molecules in the future.Ergosterol and ergosta-5,8-dien-3-ol hold great promise as new drugs against hepatocarcinoma.

抗凝活性蛋白产生菌T.albuminosus的诱变育种

真菌Termitomyces albuminosusTA-SD能产生具有抗凝活性的蛋白质TA-P。本实验采用紫外诱变法对TA-SD菌株进行诱变育种,筛选高活性的突变株。出发菌株TA-SD紫外照射40s时,正突变率和抗凝活性提高的幅度最大,分别为33.3%和104.7%。N型突变株和放线菌酮抗性突变株的正突变率和活性提高的幅度均大于S型突变株和非抗性突变株。经筛选突变株SD-A-8的抗凝活性比出发菌株提高了2.3倍。该突变株传代稳定。

Comparison of gut-associated and nest-associated microbial communities of a fungus-growing termite （Odontotermes yunnanensis）

The digestion of cellulose by fungus-growing termites involves a complex of different organisms, such as the termites themselves, fungi and bacteria. To further investigate the symbiotic relationships of fungus-growing termites, the microbial communities of the termite gut and fungus combs of Odontotermes yunnanensis were examined. The major fungus species was identified as Termitomyces sp. To compare the micro-organism diversity between the digestive tract of termites and fungus combs, four polymerase chain reaction clone libraries were created （two fungus-targeted internal transcribed spacer [ITS] - ribosomal DNA [rDNA] libraries and two bacteria-targeted 16S rDNA libraries）, and one library of each type was produced for the host termite gut and the symbiotic fimgus comb. Results of the fungal clone libraries revealed that only Termitomyces sp. was detected on the fungus comb; no non-Termitomyces fungi were detected. Meanwhile, the same fungus was also found in the termite gut. The bacterial clone libraries showed higher numbers and greater diversity of bacteria in the termite gut than in the fungus comb. Both bacterial clone libraries from the insect gut included Firmicutes, Bacteroidetes, Proteobacteria, Spirochaetes, Nitrospira, Deferribacteres, and Fibrobacteres, whereas the bacterial clone libraries from the fungal comb only contained Firmicutes, Bacteroidetes, Proteobacteria, and Acidobacteris.

Multipartite symbioses in fungus-growing termites (Blattodea: Termitidae, Macrotermitinae) for the degradation of lignocellulose

Fungus-growing termites are among the most successful herbivorous animals and improve crop productivity and soil fertility.A range of symbiotic organisms can be found inside their nests.However,interactions of termites with these symbionts are poorly understood.This review provides detailed information on the role of multipartite symbioses(between termitophiles,termites,fungi,and bacteria)in fungus-growing termites for lignocellulose degradation.The specific functions of each component in the symbiotic system are also discussed.Based on previous studies,we argue that the enzymatic contribution from the host,fungus,and bacteria greatly facilitates the decomposition of complex polysaccharide plant materials.The host-termitophile interaction protects the termite nest from natural enemies and maintains the stability of the microenvironment inside the colony.