Composition of the Cockroach Gut Microbiome in the Presence of Parasitic Nematodes

Cockroaches are parasitized by thelastomatid nematodes, which live in an obligate manner in their hindgut and interact with the resident microbial community. In the present study, a composition analysis was performed on the gut microbiome of Periplaneta fuliginosa and P. americana to investigate natural and artificial infection by thelastomatid nematodes. Nine librar- ies of the 16S rRNA gene V3–V4 region were prepared for pyrosequencing. We examined the complete gut microbiome (fore-, mid-, and hindgut) of lab-reared P. fuliginosa naturally infected with the parasitic nematode Leidynema appendiculatum and those that were nematode-free, and complemented our study by characterizing the hindgut microbial communities of lab-reared P. americana naturally infected with Hammerschmidtiella diesingi and Thelastoma bulhoesi, artificially infected with L. appendiculatum, and those that were nematode-free. Our results revealed that the fore- and midgut of naturally infected and nematode-free P. fuliginosa have close microbial communities, which is in contrast with hindgut communities; the hindgut communities of both cockroaches exhibit higher microbial diversities in the presence of their natural parasites and marked differences were observed in the abundance of the most representative taxa, namely Firmicutes, Proteobacteria, and Bacteroidetes. Our results have provided basic information and encourage further studies on multitrophic interactions in the cockroach gut as well as the thelastomatid nematodes that play a role in this environment

The composition of hindgut microbiota of Periplaneta japonica in the presence of thelastomatid parasitic nematodes

Thelastomatid nematodes (Nematoda: Oxyurida: Thelastomatoidea) are obligatory parasites that occur naturally in the hindgut of arthropods. Their origin and impact in the host is still unknown. Previous studies showed that the presence of thelastomatid nematodes in the gut of cockroaches (Periplaneta fuliginosa and P. americana) could influence the composition of their hindgut microflora. Through a metagenomic approach (16S rRNA V3-V4 sequencing), we have characterized the hindgut microbiome of P. japonica in the presence of thelastomatid nematodes (L1986, natural parasitic nematode Protrellus sp. present as a natural infection condition; and L1987, non-native parasitic nematode Leidynema appendiculatum present as an artificial infection condition). The hindgut microbiome of P. japonica in both conditions were mainly composed of Bacteroidetes, Firmicutes and Proteobacteria. Moreover, the natural and artificial infection by thelastomatid nematodes lead to shifts in the relative abundance of these main resident flora as seen in P. americana. The OTUs percentage of Bacteroidetes and Proteobacteria were higher in P. japonica infected with Protrellus sp. (L1986) than in P. japonica infected by L. appendiculatum (L1987), while OTUs from Firmicutes phylum was higher in L1987 than in L1986. This study fosters a detailed investigation in the role played by these animal parasites in their host insect

First report of the nematode Leidynema appendiculata from Periplaneta fuliginosa

The smokybrown cockroach Periplaneta fuliginosa has spread all over the world, and is now one of the most undesired inva- sive alien pests in Japan. Because cockroaches are generally infected by thelastomatid nematodes, they are being distributed around the world with their parasitic nematodes. Nothing is known about parasitic nematode species in P. fuliginosa differences, or similarity of the parasite’s population structures between the different countries of the host cockroaches. Here we investi- gated the P. fuliginosa invasive to Japan and found that 100% of individuals were infected with one nematode species. According to the morphology and the sequence of the D2/D3 expansion segment of the 28S ribosomal RNA gene, we identified the para- site as Leidynema appendiculata. This nematode reproduced by haplodiploidy and its developmental timing under various con- ditions is quite divergent. Their population in the hindgut of P. fuliginosa was controlled with a few adult females and a male. This is the first report of the thelastomatid nematode isolated from the smokybrown cockroach, and is the basis for our future research examining the origin, distribution route and immigration history of the cockroach and the impact of L. appendiculata on native Japanese cockroach species

Morphological, molecular and developmental characterization of the thelastomatid nematode Thelastoma bulhoesi (de Magalhães, 1900) (Oxyuridomorpha: Thelastomatidae) parasite of Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae) in Japan

The American cockroach Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae) has been spreading worldwide by commerce and has successfully adjusted to living with humans. There are many reports of thelastomatid parasitic nematode iso- lated from P. americana in many countries including USA, Canada, India, Argentina, Bulgaria, but not in Japan. We have in- vestigated the parasitic nematodes in P. americana lab strain and field-captured individuals in Japan and found that Thelastoma bulhoesi (de Magalhães, 1900) (Oxyuridomorpha: Thelastomatidae) parasitizes with high infection rates. We described mor- phological, molecular, and developmental characters of the parasitic nematode because such information was missing despite it has been discovered more than one hundred years ago. We described morphometrics with DIC microscopy and fine structure of male and female adult with SEM observation. We also reveal the embryonic and postembryonic development of this nema- tode. This is the first report of a thelastomatid nematode isolated from American cockroach in Japan, and the data showed here is also very useful and fundamental for further analysis of the cockroach and parasite relations

On the Status of \u3cem\u3eSuifunema peregrinatum\u3c/em\u3e (Carreno, 2017) n. comb. (Nematoda: Oxyuridomorpha: Thelastomatidae) and First Record of the Species for Japan

Morffe, Jans, Carreno, Ramon A., Ozawa, Sota, Sriwati, Rina, Hasegawa, Koichi (2019): On the status of Suifunema peregrinatum (Carreno, 2017) n. comb. (Nematoda: Oxyuridomorpha: Thelastomatidae) and first record of the species for Japan. Zootaxa 4651 (2): 351-365, DOI: https://doi.org/10.11646/zootaxa.4651.2.

Genome analysis of new Blattabacterium spp., obligatory endosymbionts of Periplaneta fuliginosa and P. japonica.

The successful adaptation of cockroaches is, in part, dependent of the activity of their obligatory endosymbionts, Blattabacterium spp., which are involved in uric acid degradation, nitrogen assimilation and nutrient provisioning. Their strategic localization, within bacteriocytes in the proximities of uric acid storage cells (urocytes), highlights their importance in the recycling of nitrogen from urea and ammonia, end-products not secreted by their host insects. In this study, we present the complete genome sequence of two new Blattabacterium spp. from Periplaneta fuliginosa (BPfu) and P. japonica (BPja), and detailed comparison with other Blattabacterium strains from different cockroach species. The genomes of BPfu and BPja show a high degree of stability as showed with for other Blattabacterium representatives, only presenting a 19-kb fragment inversion between BPja and BPfu. In fact, the phylogenomics showed BPja as an ancestor species of BPfu, BPLAN (P. americana) and BBor (Blatta orientalis), in congruence with their host cockroach phylogeny. Their functional profile is similar and closest to the omnivorous strain BBge (Blattella germanica). Interesting, BPja possesses the complete set of enzymes involved sulfate assimilatory pathway only found in BBge and BMda (Mastotermes darwiniensis). The newly sequenced genomes of BPja and BPfu emphasise the remarkable stability of Blattabacterium genomes supported by their long-term coevolution and obligatory lifestyle in their host insect