De Novo Transcriptome Analysis and Detection of Antimicrobial Peptides of the American Cockroach Periplaneta americana (Linnaeus)

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.

Insect proteins as a potential source of antimicrobial peptides in livestock production. A review

“…The majority of insect AMPs was isolated from the haemolymph of experimentally infected insects (Dang et al, 2010;Choi et al, 2012;Park et al, 2014Park et al, , 2015Kim et al, 2016), where they are produced in the fat body and in different epithelia. The production of specific AMPs targeted at a specific pathogen may be induced by septic injury by the respective pathogen inducing quick production of antimicrobial peptides (Kim et al, 2016). However, insect AMPs can also be constitutively produced in haemocytes and are released into the haemolymph in response to infection (Fu et al, 2009).…”

“…Constitutive production of AMPs in the salivary glands presumably has an additional role, i.e. the protection of eggs from infection (Isoptera: termite) (Uvell and Engstrom, 2007;Kim et al, 2016). AMPs may be also produced constitutively in the brain of insects as shown by Lee et al (2012) in the American cockroach (Periplaneta americana).…”

The American cockroach peptide periplanetasin‐4 inhibits Clostridium difficile toxin A‐induced cell toxicities and inflammatory responses in the mouse gut

“…The concentration of Peri‐4 (100 μg/ml) found to effectively inhibit toxin A‐induced cell damage is higher than the dose of Peri‐2 (10 μg/ml) previously found to exert similar effects . Given that the antimicrobial activity of Peri‐4 is also slightly weaker than that of Peri‐2 , the biological effects of these peptides in human cells appear to partially parallel their antimicrobial activities.…”

“…Notably, Peri‐2 also inhibited the intracellular toxicities caused by toxin A and reduced the gut inflammation in toxin A‐treated mice . In the present study, we assessed whether another identified peptide, Peri‐4 (13‐mer antimicrobial peptide, LRHKVYGYCVLGP) , could also inhibit C. difficile toxin A‐induced cell toxicities in vitro and ameliorate inflammatory responses in the mouse gut in vivo . Our results revealed that Peri‐4 inhibited both cell toxicities and mouse enteritis caused by C. difficile toxin A, suggesting that Peri‐4 could be a new potential agent for curing the gut inflammation induced by C. difficile toxin A.…”

De novo transcriptome assembly of the lobster cockroach Nauphoeta cinerea (Blaberidae)

“…Periplaneta americana (L.) is the most common domestic cockroach species, it shows great reproductive capability and has been used as an experimental organism in scientific studies, including neurophysiology research ( Wicher et al , 2006 ; Nishino et al , 2010 ). At least three transcriptomes of different P. americana tissues were published ( Chen et al , 2015 ; Zhang et al , 2016 ; Kim et al , 2016 ). Another cockroach species frequently used as scientific experimental organism is the German cockroach Blattella germanica (L.) ( Cruz et al , 2006 ).…”