Metabolism of Daidzein and Genistein by Gut Bacteria of the Class Coriobacteriia.

The intake of isoflavones is presumed to be associated with health benefits in humans, but also potential adverse effects of isoflavones are controversially discussed. Isoflavones can be metabolized by gut bacteria leading to modulation of the bioactivity, such as estrogenic effects. Especially bacterial strains of the Eggerthellaceae, a well-known bacterial family of the human gut microbiota, are able to convert the isoflavone daidzein into equol. In addition, metabolization of genistein is also described for strains of the Eggerthellaceae. The aim of this study was to identify and investigate gut bacterial strains of the family Eggerthellaceae as well as the narrowly related family Coriobacteriaceae which are able to metabolize daidzein and genistein. This study provides a comprehensive, polyphasic approach comprising in silico analysis of the equol gene cluster, detection of genes associated with the daidzein, and genistein metabolism via PCR and fermentation of these isoflavones. The in silico search for protein sequences that are associated with daidzein metabolism identified sequences with high similarity values in already well-known equol-producing strains. Furthermore, protein sequences that are presumed to be associated with daidzein and genistein metabolism were detected in the two type strains 'Hugonella massiliensis' and Senegalimassilia faecalis which were not yet described to metabolize these isoflavones. An alignment of these protein sequences showed that the equol gene cluster is highly conserved. In addition, PCR amplification supported the presence of genes associated with daidzein and genistein metabolism. Furthermore, the metabolism of daidzein and genistein was investigated in fermentations of pure bacterial cultures under strictly anaerobic conditions and proofed the metabolism of daidzein and genistein by the strains 'Hugonella massiliensis' DSM 101782T and Senegalimassilia faecalis KGMB04484T.

Alternariol as virulence and colonization factor of Alternaria alternata during plant infection.

The filamentous fungus Alternaria alternata is a potent producer of many toxic secondary metabolites, which contaminate food and feed. The most prominent one is the polyketide-derived alternariol (AOH) and its derivative alternariol monomethyl ether (AME). Here, we identified the gene cluster for the biosynthesis of AOH and AME by CRISPR/Cas9-mediated gene inactivation of several biosynthesis genes in A. alternata and heterologous expression of the gene cluster in Aspergillus oryzae. The 15 kb-spanning gene cluster consists of a polyketide synthase gene, pksI, an O-methyltransferase, omtI, a FAD-dependent monooxygenase, moxI, a short chain dehydrogenase, sdrI, a putative extradiol dioxygenase, doxI and a transcription factor gene, aohR. Heterologous expression of PksI in A. oryzae was sufficient for AOH biosynthesis. Co-expression of PksI with different tailoring enzymes resulted in AME, 4-hydroxy-alternariol monomethyl ether (4-OH-AME), altenusin (ALN) and altenuene (ALT). Hence, the AOH cluster is responsible for the production of at least five different compounds. Deletion of the transcription factor gene aohR led to reduced expression of pksI and delayed AOH production, while overexpression led to increased expression of pksI and production of AOH. The pksI-deletion strain displayed reduced virulence on tomato, citrus and apple suggesting AOH and the derivatives as virulence and colonization factors.

Anabolic effect of the traditional Chinese medicine compound tanshinone IIA on myotube hypertrophy is mediated by estrogen receptor.

Skeletal muscle loss during menopause is associated with a higher risk of developing diabetes type II and the general development of the metabolic syndrome. Therefore, strategies combining nutritional and training interventions to prevent muscle loss are necessary. Danshen Si Wu is a traditional Chinese medicine used for menopausal complains. One of the main compounds of Danshen Si Wu is tanshinone IIA. Physiological effects of tanshinone IIA have been described as being mediated via the estrogen receptor. Therefore, it was the aim of this study to determine its tissue specific ERα- and ERß-mediated estrogenic activity, to investigate its antiestrogenic properties, and, particularly, to study estrogen receptor-mediated biological responses to tanshinone IIA on skeletal muscle cells. The purity of tanshinone IIA was analyzed by LC-DAD-MS/MS analysis. ERα/ERß-mediated activity was dose-dependently analyzed in HEK 239 cells transfected with ERα or ERß expression vectors and respective reporter genes. Androgenic, antiandrogenic, and antiestrogenic properties of tanshinone IIA were analyzed in a yeast reporter gene assay. The effects of tanshinone IIA on proliferation and cell cycle distribution were investigated in ERα positive T47D breast cancer cells. The ability of tanshinone IIA to stimulate estrogen receptor-mediated myotube hypertrophy was studied in C2C12 myoblastoma cells. Our data show that tanshinone IIA is quite potent at stimulating ERα and ERß reporter genes with comparable efficacy. Tanshinone IIA displayed antiestrogenic and also antiandrogenic properties in a yeast reporter gene assay. It inhibited the growth of T47D breast cancer cells by suppressing proliferation and arresting the cells in G0/G1. Tanshinone IIA also stimulated the hypertrophy of C2C12 myotubes via an estrogen receptor-mediated mechanism. Summarizing our results, tanshinone IIA can be characterized as an estrogen receptor partial agonist with antiandrogenic properties. It seems to inhibit ERα-mediated cell proliferation but induces ERß-related biological responses like hypertrophy of myotubes. These findings are interesting with respect to the treatment of a variety of complains of postmenopausal females, including muscle wasting.