Comprehensive investigations of 2-phenylethanol production by the filamentous fungus Annulohypoxylon stygium.

2-Phenylethanol (2-PE) is an aromatic compound with a rose-like fragrance that is widely used in food and other industries. Yeasts have been implicated in the biosynthesis of 2-PE; however, few studies have reported the involvement of filamentous fungi. In this study, 2-PE was detected in Annulohypoxylon stygium mycelia grown in both potato dextrose broth (PDB) and sawdust medium. Among the 27 A. stygium strains investigated in this study, the strain "Jinjiling" (strain S20) showed the highest production of 2-PE. Under optimal culture conditions, the concentration of 2-PE was 2.33 g/L. Each of the key genes in Saccharomyces cerevisiae shikimate and Ehrlich pathways was found to have homologous genes in A. stygium. Upon the addition of L-phenylalanine to the medium, there was an upregulation of all key genes in the Ehrlich pathway of A. stygium, which was consistent with that of S. cerevisiae. A. stygium as an associated fungus provides nutrition for the growth of Tremella fuciformis and most spent composts of T. fuciformis contain pure A. stygium mycelium. Our study on the high-efficiency biosynthesis of 2-PE in A. stygium offers a sustainable solution by utilizing the spent compost of T. fuciformis and provides an alternative option for the production of natural 2-PE. KEY POINTS: • Annulohypoxylon stygium can produce high concentration of 2-phenylethanol. • The pathways of 2-PE biosynthesis in Annulohypoxylon stygium were analyzed. • Spent compost of Tremella fuciformis is a potential source for 2-phenylethanol.

[Analysis of progress characteristics of retinoblastoma based on single cell transcriptome sequencing].

Retinoblastoma (RB) is the most common intraocular malignant tumor in infants and young children. The key causative factors in the progression of RB remain unclear. Therefore, identifying genes closely associated with RB progression may provide important clues for disease diagnosis and gene therapy. However, tumor tissues have strong cellular heterogeneity. There may be significant differences in cell function and gene expression among cells in different pathological states. In this study, we downloaded single-cell transcriptome sequencing data of RB tumors and adjacent tissues from the GEO public database. Subsequently, we analyzed RB tumor transcriptional profiles with different disease duration at the single-cell level and identified cell groups and gene sets potentially associated with RB progression. The results showed that the tumor tissue and the adjacent tissues had overall consistency in the single-cell transcriptional map, but there were obvious differences in the distribution proportions of G1 phase cells, G2 phase cells, and microglia cells of cone precursors in RB tumor and the adjacent tissues. Furthermore, the role of three cell populations in the progression of RB tumors was emphatically analyzed. We found that in the early stage of RB tumors, cone precursor cells proliferated abnormally in G1 phase. With the progression of RB tumors, the proportion of cone precursor cells in G2 phase increased significantly. Meanwhile, the results of differential analysis of microglial populations during RB progression showed that the key genes mainly involved in immune response include RPL23, B2M, and HLA superfamily genes. This study provides new perspectives and data resources for the research of RB pathogenesis and progress.