<abstract xmlns="http://www.w3.org/1999/xhtml"><p>We morphologically and molecularly characterized segmented filamentous bacteria (SFB) associated with <italic>Rhigonema</italic> sp. nematodes in millipede hindguts. Seventy-three <italic>Riukiaria</italic> sp. millipedes were collected from a broad-leaf forest in Japan, and nematodes were excised from the millipede’s hindguts. The occurrence rate of SFB associated with nematodes was 24 % (10/41) for males, 47 % (14/30) for females, and 100 % (2/2) for juveniles. Genomic DNA was extracted from four SFB-rich nematode heads, and we obtained 40 bacterial clones via analysis of nearly full-length 16S rDNA gene sequences. At the phylum level, Firmicutes, Proteobacteria, and Verrucomicrobia accounted for 55 %, 40 %, and 5 % of SFB, respectively. In Firmicutes, Clostridiaceae (28 %) and Lachnospiraceae (15 %) were the dominant groups. Our sequences were divided into seven and three subclades between Firmicutes and Proteobacteria in the phylogenetic tree. In the Firmicutes clade, eight sequences were classified as Lachnospiraceae with a bootstrap value >83 %. A phylogenetic tree involving known uncultured Lachnospiraceae sequences characterized the phylogenetic position of SFB associated with nematodes. Our results suggest that the association of SFB with nematode bodies was probably incidental and that SFB are not always present in millipede hindguts. Our bacterial groups corresponded to those of arthropod hindgut, and SFB associated with nematodes were inferred to belong to Lachnospiraceae. Because the Lachnospiraceae sequences obtained in this study showed specific lineages that differed from all the known deposited sequence data, these groups may be unique to <italic>Riukiaria</italic> sp.</p></abstract>

We morphologically and molecularly characterized segmented filamentous bacteria (SFB) associated with Rhigonema sp. nematodes in millipede hindguts. Seventy-three Riukiaria sp. millipedes were collected from a broad-leaf forest in Japan, and nematodes were excised from the millipede’s hindguts. The occurrence rate of SFB associated with nematodes was 24 % (10/41) for males, 47 % (14/30) for females, and 100 % (2/2) for juveniles. Genomic DNA was extracted from four SFB-rich nematode heads, and we obtained 40 bacterial clones via analysis of nearly full-length 16S rDNA gene sequences. At the phylum level, Firmicutes, Proteobacteria, and Verrucomicrobia accounted for 55 %, 40 %, and 5 % of SFB, respectively. In Firmicutes, Clostridiaceae (28 %) and Lachnospiraceae (15 %) were the dominant groups. Our sequences were divided into seven and three subclades between Firmicutes and Proteobacteria in the phylogenetic tree. In the Firmicutes clade, eight sequences were classified as Lachnospiraceae with a bootstrap value >83 %. A phylogenetic tree involving known uncultured Lachnospiraceae sequences characterized the phylogenetic position of SFB associated with nematodes. Our results suggest that the association of SFB with nematode bodies was probably incidental and that SFB are not always present in millipede hindguts. Our bacterial groups corresponded to those of arthropod hindgut, and SFB associated with nematodes were inferred to belong to Lachnospiraceae. Because the Lachnospiraceae sequences obtained in this study showed specific lineages that differed from all the known deposited sequence data, these groups may be unique to Riukiaria sp.

First report of segmented filamentous bacteria associated with <italic>Rhigonema</italic> sp. (Nematoda: Rhigonematidae) dwelling in hindgut of <italic>Riukiaria</italic> sp. (Diplopoda: Xystodesmidae)

Laboratory of Forest Mycology, Graduate School of Bioresources

Forestry and Forest Products Research Institute

Helminthologia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

First report of segmented filamentous bacteria associated with  sp. (Nematoda: Rhigonematidae) dwelling in hindgut of  sp. (Diplopoda: Xystodesmidae)

We morphologically and molecularly characterized segmented filamentous bacteria (SFB) associated with Rhigonema sp. nematodes in millipede hindguts....

First report of segmented filamentous bacteria associated with Rhigonema sp. (Nematoda: Rhigonematidae) dwelling in hindgut of Riukiaria sp. (Diplopoda: Xystodesmidae)

Published Online: Jul 27, 2019

Page range: 219 - 228

Received: Feb 28, 2019

Accepted: Apr 17, 2019

DOI: https://doi.org/10.2478/helm-2019-0018

Keywords
Firmicutes, Lachnospiraceae, phylogenetic analysis, morphology, 16S rDNA

© 2019 Y. Kitagami et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

First report of segmented filamentous bacteria associated with Rhigonema sp. (Nematoda: Rhigonematidae) dwelling in hindgut of Riukiaria sp. (Diplopoda: Xystodesmidae)

Published Online: Jul 27, 2019

Page range: 219 - 228

Received: Feb 28, 2019

Accepted: Apr 17, 2019

DOI: https://doi.org/10.2478/helm-2019-0018

KeywordsFirmicutes, Lachnospiraceae, phylogenetic analysis, morphology, 16S rDNA

© 2019 Y. Kitagami et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Firmicutes, Lachnospiraceae, phylogenetic analysis, morphology, 16S rDNA