Abstract
Cockroaches are surrogate hosts for microbes that cause many human diseases. In spite of their generally destructive nature, cockroaches have recently been found to harbor potentially beneficial and medically useful substances such as drugs and allergens. However, genomic information for the American cockroach (Periplaneta americana) is currently unavailable; therefore, transcriptome and gene expression profiling is needed as an important resource to better understand the fundamental biological mechanisms of this species, which would be particularly useful for the selection of novel antimicrobial peptides. Thus, we performed de novo transcriptome analysis of P. americana that were or were not immunized with Escherichia coli. Using an Illumina HiSeq sequencer, we generated a total of 9.5 Gb of sequences, which were assembled into 85,984 contigs and functionally annotated using Basic Local Alignment Search Tool (BLAST), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) database terms. Finally, using an in silico antimicrobial peptide prediction method, 86 antimicrobial peptide candidates were predicted from the transcriptome, and 21 of these peptides were experimentally validated for their antimicrobial activity against yeast and gram positive and -negative bacteria by a radial diffusion assay. Notably, 11 peptides showed strong antimicrobial activities against these organisms and displayed little or no cytotoxic effects in the hemolysis and cell viability assay. This work provides prerequisite baseline data for the identification and development of novel antimicrobial peptides, which is expected to provide a better understanding of the phenomenon of innate immunity in similar species.
MeSH terms
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Allergens / genetics*
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Allergens / immunology
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Allergens / pharmacology
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Amino Acid Sequence
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Animals
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Antimicrobial Cationic Peptides / genetics*
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Antimicrobial Cationic Peptides / immunology
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Antimicrobial Cationic Peptides / pharmacology
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Candida albicans / drug effects
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Candida albicans / growth & development
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Candida albicans / pathogenicity
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Cell Line
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Cell Survival / drug effects
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Databases, Genetic
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Disk Diffusion Antimicrobial Tests
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Erythrocytes / drug effects
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Escherichia coli / drug effects
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Escherichia coli / growth & development
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Escherichia coli / pathogenicity
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Gene Expression
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Gene Expression Profiling
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Gene Ontology
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Hemolysis / drug effects
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High-Throughput Nucleotide Sequencing
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Human Umbilical Vein Endothelial Cells / cytology
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Human Umbilical Vein Endothelial Cells / drug effects
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Humans
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Insect Proteins / genetics*
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Insect Proteins / immunology
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Insect Proteins / pharmacology
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Keratinocytes / cytology
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Keratinocytes / drug effects
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Molecular Sequence Annotation
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Periplaneta / genetics*
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Periplaneta / immunology
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Periplaneta / microbiology
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Rats
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Staphylococcus aureus / drug effects
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Staphylococcus aureus / growth & development
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Staphylococcus aureus / pathogenicity
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Transcriptome*
Substances
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Allergens
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Antimicrobial Cationic Peptides
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Insect Proteins
Grants and funding
This work was supported by a grant from the Next-Generation BioGreen 21 Program (Project No. PJ01104304), Rural Development Administration, Republic of Korea. Insilicogen, Inc. provided support in the form of salaries for authors [SS, JP], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.