Sixteen compounds were isolated from the solid rice culture of the endophytic fungus Alternaria alstroemeriae WZ-419 derived from Pseudostellariae Radix, using silica gel, ODS, Sephadex LH-20 column chromatography, and preparative HPLC. Their structures were elucidated based on physicochemical properties and comprehensive spectroscopic analyses, and identified as alterpenoid A (1), tricycloalternarene A (2), altenusin (3), 4'-epialtenuene (4), altenuene (5), alternariol (6), altenuisol (7), 3-hydroxyalternariol-5-O-methylether (8), alternariol-9-methyl ether (9), alternariol 1′-hydroxy-9-methyl ether (10), stemphyperylenol (11), dihydroalterperylenol (12), alterinone A (13), 4-hydroxy-3-methoxy-5-(2E,6E-3,7,11-trimethyldodeca-2,6,10-trien-1-yl) benzoic acid (14), hexylitaconic acid (15), and altechromone A (16). Among them, compound 1 and 13 were new, and compounds 14 and 15 were isolated from the genus Alternaria for the first time. The antibacterial activities of compounds 1–16 were evaluated in vitro. Compounds 3, 6–8, 10, 11, 13, and 14 exhibited notable inhibitory effects against Gram-positive bacteria, with minimal inhibitory concentrations ranging from 8 to 64 µg/mL.This study isolated a series of antimicrobial metabolites from the endophytic fungi of Pseudostellariae Radix, providing new insights into their bioactive constituents and laying a foundation for further pharmacological investigations.

To screen the candidate genes associated with Musca domestica antibacterial peptides using DNA microarray technique, the hybrid probes were designed from the conservative domains of the encoded area of the insect antibacterial peptide genes in GenBank with biology software Designer 2.0, and were synthesized by a chemical process, with the assistance of the automated Gen III Microarray Spotter, those oligo probes were printed on a special ready-made glass, and a cDNA microarray was constructed. The total RNA was extracted from the fat body of Musca domestic third-instar larve induced after 24 hours by Escherichia coli and Staphylococcus aureus, the strands of cDNA were labled with fluoresceine Cy3 using the method of reverse transcription PCR, after prehybridization, hybridization and washing procedure, the results of hybridization were scanned using computer system, and the data were analyzed using the software of MIDAS, fifteen valid hybridization signals were detected through two times of hybridization and scanning (the positive samples as a control were excluded). DNA microarray technique can be successfully applied screen the candidate genes associated with Musca domestica antibacterial peptides, and further provide significant evidence to discover its antibacterial peptide new genes.
Animals ; Antimicrobial Cationic Peptides ; genetics ; Base Sequence ; Gene Expression Profiling ; Genes, Insect ; Houseflies ; genetics ; growth & development ; Larva ; genetics ; growth & development ; Molecular Sequence Data ; Oligonucleotide Array Sequence Analysis ; methods ; Oligonucleotide Probes ; chemistry