Characterization of abundance and diversity of lactic acid bacteria in the hindgut of wood- and soil-feeding termites by molecular and culture-dependent techniques

Abstract

Lactic acid bacteria have been identified as typical and numerically significant members of the gut microbiota of Reticulitermes flavipes and other wood-feeding lower termites. We found that also in the guts of the higher termites Nasutitermes arborum (wood-feeding), Thoracotermes macrothorax, and Anoplotermes pacificus (both soil-feeding), lactic acid bacteria represent the largest group of culturable carbohydrate-utilizing bacteria (3.6-5.2x10(4) bacteria per gut; 43%-54% of all colonies). All isolates were coccoid and phenotypically difficult to distinguish, but their enterobacterial repetitive intergenic consensus sequence (ERIC) fingerprint patterns showed a significant genetic diversity. Six different genotypes each were identified among the isolates from R. flavipes and T. macrothorax, and representative strains were selected for further characterization. By 16S rRNA gene sequence analysis, strain RfL6 from R. flavipes was classified as a close relative of Enterococcus faecalis, whereas strain RfLs4 from R. flavipes and strain TmLO5 from T. macrothorax were closely related to Lactococcus lactis. All strains consumed oxygen during growth on glucose and cellobiose; oxygen consumption of these and other isolates from both termite species was due to NADH and pyruvate oxidase activities, but did not result in H2O2 formation. In order to assess the significance of the isolates in the hindgut, denaturing gradient gel electrophoresis was used to compare the fingerprints of 16S rRNA genes in the bacterial community of R. flavipes with those of representative isolates. The major DNA band from the hindgut bacterial community was further separated by bisbenzimide-polyethylene glycol electrophoresis, and the two resulting bands were sequenced. Whereas one sequence belonged to a spirochete, the second sequence was closely related to the sequences of the Lactococcus strains RfLs4 and TmLO5. Apparently, those isolates represent strains of a new Lactococcus species which forms a significant fraction of the complex hindgut community of the lower termite R. flavipes and possibly also of other termites.

Lactococcus nasutitermitis sp. nov. isolated from a termite gut

“…Bacteria of the genus Lactococcus are widely distributed in a variety of fermented foods, dairy products, and plant and animal materials (Schleifer et al, 1985;Williams et al, 1990;Chen et al, 2001Chen et al, , 2014Duan et al, 2008). They have also been reported to be one of the most important lactic acid bacteria in the hindgut of wood-feeding termites (Bauer et al, 2000).In the course of a study on the diversity of culturable bacteria in the gut of a wood-feeding termite, Nasutitermes hainanensis (Isoptera: Termitidae), bacterial strain M19 T was isolated with MRS agar (MRS; Difco Lactobacilli MRS Broth) by the serial dilution method at 30 8C for 48 h. Termites were collected from Wuzhi Mountain in Hainan, China. The dissection of termite guts and preparation of gut homogenates were conducted as reported previously (Chen et al, 2012).…”

“…Bacteria of the genus Lactococcus are widely distributed in a variety of fermented foods, dairy products, and plant and animal materials (Schleifer et al, 1985;Williams et al, 1990;Chen et al, 2001Chen et al, , 2014Duan et al, 2008). They have also been reported to be one of the most important lactic acid bacteria in the hindgut of wood-feeding termites (Bauer et al, 2000).…”

Pilibacter termitis gen. nov., sp. nov., a lactic acid bacterium from the hindgut of the Formosan subterranean termite (Coptotermes formosanus)

“…Despite this problem, there remains a considerable population of bacteria in termites which may be isolated and characterized using conventional bacteriological techniques. An example includes bacteria of the order 'Lactobacillales', which have been recovered from several different species of termites, including Mastotermes darwiniensis, Cryptotermes primus, Heterotermes ferox, Coptotermes lacteus, Schedorhinotermes intermedius, Nasutitermes exitiosus (Eutick et al, 1978), Reticulitermes flavipes (Schultz & Breznak, 1978;Bauer et al, 2000), Nasutitermes arborum, Thoracotermes macrothorax and Anoplotermes pacificus (Bauer et al, 2000). Many of the endemic bacteria associated with the termite hindgut, such as species of the genus Bacteroides, Desulfovibrio termitidis and Acetonema longum, readily utilize lactic acid as a carbon source (Schultz & Breznak, 1979;Trinkerl et al, 1990;Kane & Breznak, 1991).…”

The Microbiome of Spodoptera littoralis: Development, Control and Adaptation to the Insect Host

“…Many insects have an intestinal pH in the range of 6-8, and some lepidopteran larvae have an even higher pH (11-12) in their midguts [124,125]. The hindgut harbors high bacterial diversity and density in several insects, such as cockroaches, crickets and termites [126][127][128].…”