[Silkworm excrement bacterial communities diversity in different instars based on 16S rDNA sequence analysis]

Area of Science:

• Microbiology
• Genomics
• Biotechnology

Background:

• Silkworm excrement (Bombyx mori) is a potential source for traditional medicine.
• Understanding its bacterial communities is crucial for its efficacy and utilization.
• Drying is a common processing method, but its impact on bacterial diversity is not well-understood.

Purpose of the Study:

• To investigate the bacterial community diversity in silkworm excrement of different ages before and after drying.
• To clarify the influence of drying treatment on bacterial composition and abundance.
• To provide a scientific basis for the utilization of silkworm excrement in medicine.

Main Methods:

• High-throughput sequencing of the 16S rDNA-V4 variable region.
• Bioinformatic analysis using QIIME and Mothur for operational taxonomic units (OTUs) and diversity indices.
• Functional gene prediction using PICRUSt.
• Comparison of bacterial communities before and after drying across different silkworm ages.

Main Results:

• Proteobacteria was the dominant phylum (89.3%), followed by Actinobacteria (5.0%).
• Drying significantly reduced bacterial abundance and diversity, particularly in fifth-instar silkworm excrement.
• Drying decreased pathogenic bacteria, enhancing the quality of silkworm excrement for medicinal applications.
• Fifth-instar silkworm excrement exhibited a more favorable bacterial profile for medicinal use compared to younger silkworms.

Conclusions:

• Drying treatment effectively reduces pathogenic bacteria in silkworm excrement, improving its quality for medicinal purposes.
• Silkworm excrement from older silkworms (fifth instar) is more suitable for medicinal applications due to its bacterial composition.
• High-throughput sequencing provides robust data for studying silkworm excrement's bacterial communities and optimizing its use.