Characterization Of Two Paenibacillus Species Isolated From Nasutitermes Hainanensis With Polyphasic Approach

Termite is a kind of social insect that belongs to Isoptera. It distributes widely in almost all continents excepted Antarctica and especially abundant in tropical and subtropical regions. Termites are efficient cellulose and hemicellulose degraders in nature. The ability of cellulose digestion is closely related to their intestinal symbiotic bacteria, archaea and protozoa. The association between termites and their gut microorganisms is a good model system for the research of the symbiosis mechanisms. Nasutitermes hainanensis is a representative of wood-feeding higher termite. Previous studies showed that there are many symbiotic bacteria in their intestinal tracts, and the amount and types of bacteria in different gut sections are obviously different. In this paper, we characterized two new bacterial species that previously isolated from the gut of N. hainanensis with polyphasic approach, which formed a foundation for further analysis of their physiological functions. The main results are as following:1.Characterization of Strain P5-1 with a polyphasic approachThe strain P5-1 isolated from the gut of N. hainanensis was characterized using a polyphasic approach. Colonies of Strain P5-1 were circular, smooth and transparent on TSB agar plates. Cells were Gram-staining-positive, aerobic, non-motile, terminal endospore-forming rods (0.5-0.7� 2.2-3.5 ?m). Phylogenetic analysis of 16S rRNA genes showed that Strain P5-1 was most closely related to Paenibacillus sepulcri LMG19508Twith a similarity of 97.5%. The optimum growth temperature of Strain P5-1 was 30? and the optimum growth pH was 7.5. Cells of Strain P5-1 can not grow in the presence of 2%(w/v) NaCl. D-maltose, D-glucose and mannitol can be assimilated. Strain P5-1 can produce H2S, but can not hydrolyse starch and casein. The activities of urease, arginine dihydrolase, P-galactosidase and a-galactosidase were positive. The predominant cellular fatty acids were anteiso-C15:0 and iso-C15:0. The major respiratory quinone was MK-7. The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid, an unidentified glycolipid and an unidentified aminophospholipid. The diamino acid in the cell wall peptidoglycan was meso-diaminopimelic acid. The genomic DNA G+C content of Strain P5-1 was 48.912mol%. These results supported the assigment of Strain P5-1 to the genus Paenibacillus and distinguished it from the previously described Paenibacillus species. Hence, we propose that Strain P5-1 represents a novel species of the genus Paenibacillus, with the name Paenibacillus nasutitermitis sp. nov. The type strain is P5-1T(=NBRC111536T=CGMCC1.15178T).2.Characterization of Strain NP1 with a polyphasic approachThe strain NP1 isolated from the gut of N. hainanensis was characterized using a polyphasic approach. Colonies of Strain NP1 were circular, smooth and moist on TSB agar plates. Cells were Gram-staining-negative, aerobic, non-motile, subterminal endospore forming rods (0.3-0.4um�l.7-3.0um). Phylogenetic analysis of 16S rRNA genes showed that Strain NP1 was most closely related to Paenibacillus curdlanolyticus JCM12163T with a similarity of 97%. The optimum growth temperature of Strain NP1 was 30? and the optimum growth pH was7.0. There was no growth in the presence of 2%(w/v) NaCl. D-maltose, D-glucose, D-mannose, D-ribose, D-lactose and D-cellobiose can be assimilated. Strain NP1 can produce H2S but can not hydrolyse casein and starch. The activities of urease, arginine dihydrolase, P-galactosidase, ?-galactosidase, P-glucosidase and ?-glucosidase were positive. The predominant cellular fatty acids were anteiso-Cis:o and iso-C160.The major respiratory quinone was MK-7, the polar lipids were composed of phosphatidylglycerol,diphosphatidylglycerol, phosphatidylethanolamine and unidentified phospholipid, unidentified aminophospholipid. The diamino acid in the cell wall peptidoglycan was meso-diaminopimelic acid.The genomic DNA G+C content of S train NP1 was 55.62mol%.These results supported the assignment of Strain NP1 to the genus Paenibacillus and distinguished it from the previously described Paenibacillus species. Hence, we propose that Strain NP1 represents a novel species of the genus Paenibacillus with the name Paenibacillus termiticellulosilyticus sp.nov. The type strain is NP1T(=CCTCCM2016072T).