ABSTRACT
BACKGROUND: Cockroaches are of vital importance medically and hygienically as they can disperse human pathogenic agents and are especially responsible for food contamination and spreading of food borne pathogens. In this study, part of mtDNA-COI gene of five common pest cockroaches was tested for diagnostic and phylogenetic purposes. METHODS: We have described barcode region of mtDNA-COI gene of five cockroach species: Blattella germanica, Blatta orientalis, Periplaneta americana, Shelfordella lateralis, and Supella longipalpa, along with the development of a PCR-RFLP method for rapid detection and differentiation of these health pest species. RESULTS: The PCR generates a single 710 bp-sized amplicon in all cockroach specimens, followed by direct sequencing. AluI predicted from the sequencing data provided different RFLP profiles among five species. There was a significant intra-species variation within the American cockroach populations, but no genetic variation within other species. Accordingly, phylogenetic analysis demonstrates common monophyly for cockroach families in agreement with conventional taxonomy. However S. longipalpa (Ectobiidae) diverged as an early ancestor of other cockroaches and was not associated with other Ectobiidae. CONCLUSION: The PCR-RFLP protocol might be useful when the conventional taxonomic methods are not able to identify specimens, particularly when only small body parts of specimens are available or they are in a decaying condition. mtDNA-COI gene shows potentially useful for studying phylogenetic relationships of Blattodea order.
ABSTRACT
BACKGROUND: Cockroaches are of vital importance medically and hygienically. They are able to contaminate foods and act as vectors of pathogenic agents such as bacteria, protozoa, and parasites to human environment either mechanically or through their digestive system. Cockroaches belong to the phylum Arthropoda, class Insecta, and order Blattodea or Blattaria. To date, over 4,500 cockroach species have been reported from different parts of the world. We overviewed the documents involved Iranian cockroaches to up-to-date checklist of cockroach species distributed in various provinces of Iran. METHODS: An extensive literature review was performed in 2013 on Iranian handbooks, reports and published data available since 1986 to obtain a comprehensive list of Iranian cockroaches. Furthermore, in an entomological survey in Tehran, cockroach specimens were collected and identified based on morphological and the DNA sequences of the mitochondrial cytochrome oxidase subunit II (COII) gene (mt-DNA COII) characteristics. RESULTS: Morphological characterization revealed presence of an un-described species very similar to Polyphaga aegyptiaca, P. indica and somehow to Pycnoscelus surinamensis, however, supplementary molecular analysis revealed the species was associated with Polyphaga of Corydiidae (Polyphagidae). With regards to the report of the un-described species, the cockroach fauna of Iran includes three families, 14 genera, and 26 species. CONCLUSION: Some species has not been collected or reported recently and also many geographical regions of the country have not been studied yet, hence a systematic research is required to reveal the real cockroach list of the country. Geographical distributions, nomination changes, and synonyms of cockroach species are presented.
ABSTRACT
BACKGROUND: Cockroaches mechanically spread pathogenic agents, however, little is known about their gut microbiota. Identification of midgut microbial community helps targeting novel biological control strategies such as paratransgenesis. Here the bacterial microbiota of Periplaneta americana midgut, were identified and evaluated for finding proper paratransgenesis candidate. METHODS: Midgut of specimens were dissected and cultivated in different media. The bacterial isolates were then identified using the phenotypic and 16S-rRNA sequencing methods. RESULTS: The analytical profile index (API) kit showed presence of 11 bacterial species including: Escherichia coli, Shigella flexineri, Citrobacter freundii, E. vulneris, Enterobacter cloacae, Yersinia pseudotuberculosis, Y. intermedia, Leclericia adecarboxylata, Klebsiella oxytoca, K. planticola, and Rahnella aquatilis in the cockroach midguts. The first three species are potentially symbiotic whereas others are transient. The conventional plating method revealed presence of only four isolates of Salmonella, E. coli, and Proteus which in three cases mismatched with API and 16S-rRNA genotyping. The API correctly identified the four isolates as Shigella flexneri, Citrobacter freundii, and E. coli (n= 2). 16S-rRNA sequence analysis confirmed the API results; however the C. freundii sequence was identical with C. murliniae indicating lack of genetic variation in the gene between these two closely related species. CONCLUSION: A low number of potentially symbiotic bacteria were found in the American cockroach midguts. Among them Enterobacter cloacae is a potential candidate for paratransgenesis approach whereas other bacteria are pathogens and are not useful for the approach. Data analysis showed that identification levels increase from the conventional to API and to genotyping respectively.
