• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.537-542
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• 2020

Cockroaches inhabit various habitats, which will influence their microbiome. Although the microbiome can be influenced by the diet and environmental factors, it can also differ between species. Therefore, we conducted 16S rDNA-targeted high-throughput sequencing to evaluate the overall bacterial composition of the microbiomes of 3 cockroach species, Periplaneta americana, P. japonica, and P. fuliginosa, raised in laboratory for several generations under the same conditions. The experiments were conducted using male adult cockroaches. The number of operational taxonomic units (OTUs) was not significantly different among the 3 species. With regard to the Shannon and Pielou indexes, higher microbiome values were noted in P. americana than in P. japonica and P. fuliginosa. Microbiome composition was also evaluated, with endosymbionts accounting for over half of all OTUs in P. japonica and P. fuliginosa. Beta diversity analysis further showed that P. japonica and P. fuliginosa had similar microbiome composition, which differed from that of P. americana. However, we also identified that P. japonica and P. fuliginosa host distinct OTUs. Thus, although microbiome compositions may vary based on multiple conditions, it is possible to identify distinct microbiome compositions among different Periplaneta cockroach species, even when the individuals are reared under the same conditions.

• Journal of Life Science
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• v.27 no.6
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• pp.694-701
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• 2017

Mycoplasma genitalium represents the smallest genome among mono-cultivable prokaryotes. To discover and compare the orthologs (conservative genes) among M. genitalium and 14 prokaryotes that are uncultivable and have less orthologs than M. genitalium, COG (clusters of orthologous groups of protein) analyses were applied. The analyzed prokaryotes were M. genitalium, one hyperthermophilic exosymbiotic archaeon Nanoarchaeum equitans, four intracellular plant pathogenic eubacteria of Candidatus Phytoplasma genus, and nine endosymbiotic eubacteria of phloem- and xylem-feeding insects. Among 367 orthologs of M. genitalium, 284 orthologs were conservative between M. genitalium and at least one other prokaryote. All 15 prokaryotes commonly have 29 orthologs, representing the significance of proteins in life. They belong to 25 translation-related, including 22 ribosomal proteins, 3 subunits of RNA polymerase, and 1 protein-folding-related. Among the 15 prokaryotes, 40 orthologs were only found in all four Candidatus Phytoplasma. The other nine Candidatus, all endosymbionts with insects, showed only a single common COG0539 (ribosomal protein S1), representing the diversity of orthologs among them. These results might provide clues to understand conservative genes in uncultivable prokaryotes, and may be helpful in industrial areas, such as handling prokaryotes producing amino acids and antibiotics, and as precursors of organic synthesis.