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Moriya Ohkuma - One of the best experts on this subject based on the ideXlab platform.

  • lactococcus reticulitermitis sp nov isolated from the gut of the subterranean termite Reticulitermes speratus
    International Journal of Systematic and Evolutionary Microbiology, 2018
    Co-Authors: Masahiro Yuki, Mitsuo Sakamoto, Yuki Nishimura, Moriya Ohkuma
    Abstract:

    Strain Rs-Y01T was isolated from the gut of the wood-feeding subterranean termite Reticulitermes speratus. Phylogenetic analysis based on 16S rRNA gene sequence indicated that the strain Rs-Y01T belonged to the genus Lactococcus and was most closely related to Lactococcus raffinolactis JCM 5706T with 98.1 % similarity in the 16S rRNA gene, followed by Lactococcus piscium JCM 16647T (97.2 %). Genomic comparisons of strain Rs-Y01T with L. raffinolactis JCM 5706Twere made using the Genome-to-Genome Distance Calculator and average nucleotide identity analysis (values indicated 29.2 and 84.6 %, respectively). Strain Rs-Y01T was a Gram-stain-positive, facultatively anaerobic, non-motile coco-bacilli and formed l-lactic acid. The sugar fermentation and enzyme reactions of strain Rs-Y01T differed from those of other species of the genus Lactococcus . The major cellular fatty acids were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c; 32.0 %), C16 : 0 (29.7 %) and C14 : 0 (18.1 %). Based on these characteristics, strain Rs-Y01T represents a novel species of the genus Lactococcus , for which the name Lactococcus reticulitermitis sp. nov. is proposed. The type strain is Rs-Y01T (=JCM 32106T=DSM 105715T).

  • Screening and evolution of a novel protist xylose isomerase from the termite Reticulitermes speratus for efficient xylose fermentation in Saccharomyces cerevisiae
    Biotechnology for biofuels, 2017
    Co-Authors: Satoshi Katahira, Moriya Ohkuma, Shigeharu Moriya, Nobuhiko Muramoto, Risa Nagura, Nobuki Tada, Noriko Yasutani, Toru Onishi, Kenro Tokuhiro
    Abstract:

    The yeast Saccharomyces cerevisiae, a promising host for lignocellulosic bioethanol production, is unable to metabolize xylose. In attempts to confer xylose utilization ability in S. cerevisiae, a number of xylose isomerase (XI) genes have been expressed heterologously in this yeast. Although several of these XI encoding genes were functionally expressed in S. cerevisiae, the need still exists for a S. cerevisiae strain with improved xylose utilization ability for use in the commercial production of bioethanol. Although currently much effort has been devoted to achieve the objective, one of the solutions is to search for a new XI gene that would confer superior xylose utilization in S. cerevisiae. Here, we searched for novel XI genes from the protists residing in the hindgut of the termite Reticulitermes speratus. Eight novel XI genes were obtained from a cDNA library, prepared from the protists of the R. speratus hindgut, by PCR amplification using degenerated primers based on highly conserved regions of amino acid sequences of different XIs. Phylogenetic analysis classified these cloned XIs into two groups, one showed relatively high similarities to Bacteroidetes and the other was comparatively similar to Firmicutes. The growth rate and the xylose consumption rate of the S. cerevisiae strain expressing the novel XI, which exhibited highest XI activity among the eight XIs, were superior to those exhibited by the strain expressing the XI gene from Piromyces sp. E2. Substitution of the asparagine residue at position 337 of the novel XI with a cysteine further improved the xylose utilization ability of the yeast strain. Interestingly, introducing point mutations in the corresponding asparagine residues in XIs originated from other organisms, such as Piromyces sp. E2 or Clostridium phytofermentans, similarly improved xylose utilization in S. cerevisiae. A novel XI gene conferring superior xylose utilization in S. cerevisiae was successfully isolated from the protists in the termite hindgut. Isolation of this XI gene and identification of the point mutation described in this study might contribute to improving the productivity of industrial bioethanol.

  • dysgonomonas termitidis sp nov isolated from the gut of the subterranean termite Reticulitermes speratus
    International Journal of Systematic and Evolutionary Microbiology, 2015
    Co-Authors: Ajeng K Pramono, Mitsuo Sakamoto, Yuichi Hongoh, Takao Iino, Moriya Ohkuma
    Abstract:

    A facultatively anaerobic, Gram-stain-negative, non-motile and rod-shaped bacterium, strain N-10T, was isolated from the gut of the termite Reticulitermes speratus. Strain N-10T was closely related to Dysgonomonas gadei JCM 16698T according to 16S rRNA gene sequence similarity analysis (98 %) and DNA–DNA relatedness value (≤61.3 %). The optimum growth temperature of strain N-10T was 30 °C, which was distinct from that (37 °C) of known species of the genus Dysgonomonas . Growth of strain N-10T was inhibited on medium containing 5 or 20 % bile, unlike other species of the genus Dysgonomonas . In addition, acid production in the API 20A system and enzymic reactions in the Rapid ID 32A system of strain N-10T differed from those of other species of the genus Dysgonomonas . Based on these characteristics, strain N-10T represents a novel species of the genus Dysgonomonas , for which the name Dysgonomonas termitidis sp. nov. is proposed. The type strain is N-10T ( = JCM 30204T = CCUG 66188T).

  • bacteroides reticulotermitis sp nov isolated from the gut of a subterranean termite Reticulitermes speratus
    International Journal of Systematic and Evolutionary Microbiology, 2013
    Co-Authors: Mitsuo Sakamoto, Moriya Ohkuma
    Abstract:

    An obligately anaerobic, non-pigmented, non-spore-forming, Gram-staining-negative, rod-shaped bacterium, designated strain Rs-03T, was isolated from the gut of the subterranean termite Reticulitermes speratus. The taxonomic position of the novel strain was determined by following a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Rs-03T was a member of the genus Bacteroides and was most closely related to Bacteroides thetaiotaomicron JCM 5827T (95.0 % sequence similarity), Bacteroides faecis JCM 16478T (94.8 %) and Bacteroides xylanisolvens JCM 15633T (94.3 %). The results of hsp60 gene sequence analysis indicated that the novel strain was different from established members of the genus Bacteroides . Strain Rs-03T was saccharolytic and produced succinic and acetic acids, with small amounts of propionic acid, as metabolic end products. The major cellular fatty acids of strain Rs-03T were anteiso-C15 : 0, C18 : 1ω9c and iso-C17 : 0 3-OH. The major menaquinones were MK-10 and MK-9 and the genomic DNA G+C content was 44.9 mol%. Based on these data, strain Rs-03T represents a novel species in the genus Bacteroides , for which the name Bacteroides reticulotermitis sp. nov. is proposed. The type strain is Rs-03T ( = JCM 10512T = CCUG 62153T).

  • environmental cdna analysis of the genes involved in lignocellulose digestion in the symbiotic protist community of Reticulitermes speratus
    FEMS Microbiology Ecology, 2007
    Co-Authors: Nemuri Todaka, Moriya Ohkuma, Kanako Saita, Shigeharu Moriya, Tomoko Hondo, Isao Kiuchi, Hirotoshi Takasu, Carninci Piero, Yoshihide Hayashizaki, Toshiaki Kudo
    Abstract:

    To clarify the lignocellulolytic process of the lower termite symbiotic protistan system, we constructed a cDNA library from an as yet uncultivated symbiotic protist community of the lower termite Reticulitermes speratus. The library was constructed by the biotinylated CAP trapper method and analyzed by one-pass sequencing. Phylogenetic analysis of actin orthologs confirmed that the resulting library reflected the intact organismal and mRNA composition of the symbiotic system. The contents of the library included abundant numbers of lignocellulolytic genes of the glycosyl hydrolase family orthologs (families 3, 5, 7, 8, 10, 11, 26, 43, 45 and 62). Our results clearly indicated that a multiple family of glycosyl hydrolase enzymes was involved in the protistan cellulose degradation system. The data also suggested that the most extensively expressed enzyme was glycosyl hydrolase family 7, a cellobiohydrolase ortholog. This family of enzymes enables the degradation of crystalline cellulose, the principal component of wood biomass.

Toshiaki Kudo - One of the best experts on this subject based on the ideXlab platform.

  • Heterologous Expression and Characterization of a Glycoside Hydrolase Family 45 endo-β-1,4-Glucanase from a Symbiotic Protist of the Lower Termite, Reticulitermes speratus
    Applied Biochemistry and Biotechnology, 2013
    Co-Authors: Masato Otagiri, Crisanto M. Lopez, Manabu Arioka, Katsuhiko Kitamoto, Toshiaki Kudo, Shigeharu Moriya
    Abstract:

    The termite symbiotic system is one of the efficient lignocellulose degradation systems. We tried to express and characterize a novel cellulolytic enzyme from this system. Here, we report the isolation of an endo -β-1,4-glucanase gene homolog of glycoside hydrolase family 45 from a symbiotic protistan community of Reticulitermes speratus. Heterologous expression of this gene was performed using the expression system of Aspergillus oryzae . Analysis of enzymatic properties revealed 786 μmol/min/mg protein in specific activity, a V _max of 833.0 units/mg protein, and a K _m value of 2.58 mg/ml with carboxymethyl cellulose as the substrate. Thin-layer chromatography analysis showed that RsSymEG2 produces cellobiose from cellodextrins larger than cellohexaose. This enzyme showed high specific activity like other endo -β-1,4-glucanases from the symbiotic system of termites. It means that the termite symbiotic system is a good resource for highly active endo -β-1,4-glucanases.

  • Heterologous Expression and Characterization of an Endoglucanase from a Symbiotic Protist of the Lower Termite, Reticulitermes speratus
    Applied biochemistry and biotechnology, 2009
    Co-Authors: Nemuri Todaka, Crisanto M. Lopez, Tetsushi Inoue, Kanako Saita, Jun-ichi Maruyama, Manabu Arioka, Katsuhiko Kitamoto, Toshiaki Kudo, Shigeharu Moriya
    Abstract:

    RsSymEG, an endoglucanase of glycosyl hydrolase family (GHF) 7 encoded by a transcript isolated from the symbiotic protist of the termite Reticulitermes speratus, is expressed in Aspergillus oryzae. Interestingly, purified RsSymEG1 has a relatively higher specific activity (603 μmol min−1 mg−1 protein) and V max value (769.6 unit/mg protein) than previously reported data for GHF7 endoglucanase of Trichoderma ressei. It also has the same K m value (1.97 mg/ml) with Clostridium cellulolyticum enzymes that contain cellulose binding module, a property indicative of high affinity to substrate, though no cellulose binding module is found within it. Thin-layer chromatography analysis revealed that RsSymEG1 preferentially hydrolyzes the β-1,4-cellulosic linkage of cellodextrins into cellobiose and glucose.

  • environmental cdna analysis of the genes involved in lignocellulose digestion in the symbiotic protist community of Reticulitermes speratus
    FEMS Microbiology Ecology, 2007
    Co-Authors: Nemuri Todaka, Moriya Ohkuma, Kanako Saita, Shigeharu Moriya, Tomoko Hondo, Isao Kiuchi, Hirotoshi Takasu, Carninci Piero, Yoshihide Hayashizaki, Toshiaki Kudo
    Abstract:

    To clarify the lignocellulolytic process of the lower termite symbiotic protistan system, we constructed a cDNA library from an as yet uncultivated symbiotic protist community of the lower termite Reticulitermes speratus. The library was constructed by the biotinylated CAP trapper method and analyzed by one-pass sequencing. Phylogenetic analysis of actin orthologs confirmed that the resulting library reflected the intact organismal and mRNA composition of the symbiotic system. The contents of the library included abundant numbers of lignocellulolytic genes of the glycosyl hydrolase family orthologs (families 3, 5, 7, 8, 10, 11, 26, 43, 45 and 62). Our results clearly indicated that a multiple family of glycosyl hydrolase enzymes was involved in the protistan cellulose degradation system. The data also suggested that the most extensively expressed enzyme was glycosyl hydrolase family 7, a cellobiohydrolase ortholog. This family of enzymes enables the degradation of crystalline cellulose, the principal component of wood biomass.

  • spatial distribution of bacterial phylotypes in the gut of the termite Reticulitermes speratus and the bacterial community colonizing the gut epithelium
    FEMS Microbiology Ecology, 2005
    Co-Authors: Hideaki Nakajima, Yuichi Hongoh, Toshiaki Kudo, Ron Usami, Moriya Ohkuma
    Abstract:

    The bacterial community colonizing the gut wall of the termite Reticulitermes speratus was characterized without cultivation. Analysis of 16S rRNA genes after fractionation of the gut revealed that the bacterial composition on the gut wall was diverse and significantly different from that able to move unconfined in the gut fluid or physically associated with the gut protists. Actinobacteria, Firmicutes and Bacteroidetes were dominant on the gut wall, but Spirochaetes and the Termite group 1 phylum, abundant in the gut lumen, were relatively rare. A sequence-specific probe enabled the in situ detection of a rod-shaped Actinobacteria member, abundantly colonizing the gut paunch epithelium.

  • molecular analysis of bacterial microbiota in the gut of the termite Reticulitermes speratus isoptera rhinotermitidae
    FEMS Microbiology Ecology, 2003
    Co-Authors: Yuichi Hongoh, Moriya Ohkuma, Toshiaki Kudo
    Abstract:

    The molecular diversity and community structure of bacteria from the gut of the termite Reticulitermes speratus were analyzed by the sequencing of near-full-length 16S rRNA genes, amplified by polymerase chain reaction. The results of the analysis of 1344 clones indicated a predominance of spirochetes in the gut. Spirochetal clones accounted for approximately half of the analyzed clones. The clones related to Bacteroides, Clostridia, and the candidate division Termite Group I each accounted for approximately 5–15% of the analyzed clones. The rest were comprised of Proteobacteria, Actinobacteria, Mycoplasma and others. Using the criterion of 97% sequence identity, the clones were sorted into 268 phylotypes, including 100 clostridial, 61 spirochetal and 31 Bacteroides-related phylotypes. More than 90% of the phylotypes were found for the first time, and some constituted monophyletic clusters with sequences recovered from the gut of other termite species.

Kiyoto Maekawa - One of the best experts on this subject based on the ideXlab platform.

  • Male-specific molecular genetic markers in the Japanese subterranean termite Reticulitermes speratus
    Insectes Sociaux, 2017
    Co-Authors: Yoshinobu Hayashi, Osamu Kitade, Kiyoto Maekawa, Toru Miura, K. Oguchi, Katsushi Yamaguchi, Shuji Shigenobu
    Abstract:

    Sex-specific genetic markers are often required for studying sex-associated phenomena. Restriction site-associated DNA sequencing (RAD-seq) allows detection of a huge number of genetic polymorphisms and is particularly useful for identifying sex-specific DNA-based (or molecular) genetic markers. Although sex determination in the Japanese subterranean termite Reticulitermes speratus depends on an XX/XY chromosome system, in which male-specific molecular genetic markers can be developed, no such marker has been developed. In this study, we developed male-specific genetic markers for R. speratus using RAD-seq with two restriction enzymes (i.e. double digest [dd] RAD-seq). We subjected 58 field-collected individuals per sex to ddRAD-seq and obtained around 210 million paired-end reads. Our in silico analysis of ddRAD-seq data detected 25 male-specific loci but no female-specific loci, thus confirming an XX/XY system. To verify the male specificity of those loci, we conducted PCR with primers designed for male-specific loci. Accordingly, we obtained male-specific PCR amplifications in six of the 25 loci. Furthermore, we examined whether these six male-specific markers were also applicable to individuals derived from four Japanese populations of R. speratus, including from the northern and southern ends of the distribution range in Japan. Of the six markers, five exhibited male-specific PCR amplifications in all four populations; the sixth was applicable to three populations. PCR amplification tests for cross-species applicability in R. kanmonensis found that none of these markers were cross-species applicable. The six male-specific markers would be useful for sex and sex chromosome identification in R. speratus individuals at all life stages.

  • Gene expression and molecular phylogenetic analyses of beta-glucosidase in the termite Reticulitermes speratus (Isoptera: Rhinotermitidae).
    Journal of insect physiology, 2014
    Co-Authors: Keisuke Shimada, Kiyoto Maekawa
    Abstract:

    Beta-glucosidase (BG) is known as a multifunctional enzyme for social maintenance in terms of both cellulose digestion and social communication in termites. However, the expression profiles of each BG gene and their evolutionary history are not well understood. First, we cloned two types of BG homologs (RsBGI and RsBGII) from the termite Reticulitermes speratus (Kolbe). Gene expression analyses showed that RsBGI expression levels of primary queens and kings from 30 to 100 days after colony foundation were high, but those of reproductives dropped after day 400. Extremely low gene expression levels of RsBGI were observed in eggs, whereas workers had significantly higher expression levels than those of soldiers and other colony members. Consequently, RsBGI gene expression levels changed among each developmental stage, and RsBGI was shown to be involved in cellulose digestion. On the other hand, the RsBGII gene was consistently expressed in all castes and developmental stages examined, and notable expression changes were not observed among them, including in eggs. It was indicated that RsBGII is a main component involved in social communication, for example, the egg-recognition pheromone shown in this species previously. Finally, we obtained partial gene homologs from other termite and cockroach species, including the woodroach (genus Cryptocercus), which is the sister group to termites, and performed molecular phylogenetic analyses. The results showed that the origin of the BG gene homologs preceded the divergence of termites and cockroaches, suggesting that the acquisition of multifunctionality of the BG gene also occurred in cockroach lineages.

  • High Laccase2 expression is likely involved in the formation of specific cuticular structures during soldier differentiation of the termite Reticulitermes speratus
    Arthropod structure & development, 2013
    Co-Authors: Yudai Masuoka, Satoshi Miyazaki, Ryota Saiki, Tsutomu Tsuchida, Kiyoto Maekawa
    Abstract:

    Termite soldiers are morphologically specialized for colony defense. Analysis of the mechanisms of soldier differentiation is important for understanding the establishment of termite societies. Soldiers differentiate from workers through a presoldier stage and have well-sclerotized and pigmented cuticles. These characteristics are important for nest defense and are likely to be caused by soldier-specific mechanisms of cuticular tanning. The molecular mechanisms leading to cuticular tanning have not been elucidated. Laccase2 (Lac2) plays important roles in this process in insects, and we hypothesized that Lac2 expression may be involved in soldier-specific cuticular tanning. We observed inner and outer head cuticle changes and compared the Lac2 expression patterns among three molts (worker-worker, worker-presoldier and presoldier-soldier) in the termite Reticulitermes speratus. Quantitative analyses of head cuticle colors showed that the color properties changed more conspicuously in presoldier-soldier molts than in the other two molts. Histological observations showed that the exocuticles of soldier heads were substantially thicker than those of worker and presoldier heads, underwent tanning before or just after ecdysis, and were pigmented at earlier time points than other molts. Finally, markedly higher Lac2 expression levels were observed just before and after ecdysis only in the presoldier-soldier molt. These results suggest that specific cuticular formation occurs in the exocuticles during soldier differentiation, and that the high level of Lac2 expression during the presoldier-soldier molt is related to soldier-specific cuticular tanning. We speculate that evolution of the regulatory mechanisms of Lac2 expression were important for the acquisition of soldier-specific cuticles.

  • Relationships between frontal-gland formation and mandibular modification during JH III-induced presoldier differentiation in the termite Reticulitermes speratus Isoptera Rhinotermitidae
    Entomological Science, 2011
    Co-Authors: Dai Watanabe, Kiyoto Maekawa
    Abstract:

    Termite soldiers engage in colony defense and they possess weapons in order to attack enemies. Defensive strategies vary among species depending on the morphology of the soldier's weapons. Both the frontal gland and elongated mandibles are formed during soldier differentiation of Reticulitermes speratus workers, which is associated with an increase in juvenile hormone (JH) titer. It was shown that the amount of JH applied and coexistence with soldiers affected mandibular elongation of the induced presoldiers. To determine the relationship between applied JH concentration and frontal‐gland development of R. speratus, mandibular modification and frontal‐gland formation of presoldiers induced by 20, 40 and 80 µg JH III in the presence or absence of soldiers were observed. Both presoldier differentiation rates and their mandibular lengths were affected by the presence of soldiers in treatments with 20 and 40 µg JH III. Especially in the treatment with 20 µg JH III, frontal‐pore malformation was observed in some presoldiers. All presoldiers with a malformed frontal pore had almost the same sized mandibles, compared with those of stationarily molted workers. Interestingly, sections of these presoldiers showed that frontal‐gland invagination occurred incompletely in comparison with presoldiers with relatively elongated mandibles. Consequently, frontal‐gland formation might be affected by JH titer (applied and endogenous JH), and individuals with a malformed frontal pore were probably differentiated by JH titers only slightly above the threshold for presoldier differentiation.

  • soldier presence suppresses presoldier differentiation through a rapid decrease of jh in the termite Reticulitermes speratus
    Journal of Insect Physiology, 2011
    Co-Authors: Dai Watanabe, Toru Miura, Hiroki Gotoh, Kiyoto Maekawa
    Abstract:

    Abstract The regulation of caste differentiation is essential to insect eusociality. Termite soldiers are sterile and cannot eat by themselves because they have specialized mouth morphology. Almost all termite species have a soldier caste, and the soldier ratio per colony is maintained at a low level, probably by elaborate regulatory mechanisms. Although the soldier presence is considered to negatively affect soldier differentiation in all examined species, the detailed mechanism remains unclear. Presoldier differentiation can be induced artificially by juvenile hormone (JH) application to workers, showing that JH is a key factor underlying the regulation of soldier differentiation. In this study, to elucidate physiological changes in workers because of the soldier presence during the molt into presoldiers, JH III applications and JH titer quantifications were carried out in the rhinotermitid termite Reticulitermes speratus. Firstly, the effects of soldier presence before the molt into presoldiers induced by JH III application to workers were investigated. The rates of presoldier molt induced by the treatments with soldiers were significantly lower than those without soldiers. Secondly, worker JH titers in the presence or absence of soldiers were quantified by LC–MS on day 0, 5, 10, and 15 after JH application. Results indicated that the worker JH titers (endogenous + applied JH III) in the presence of soldiers were significantly lower than those without soldiers on day 5 after the JH treatment. On days 10 and 15, such soldier effects were not observed. Finally, the effective duration of soldier presence after the JH application was elucidated. A 4 day period of co-existence with soldiers suppressed presoldier differentiation, suggesting that the soldier presence rapidly decreased the JH titer in other colony members (i.e., workers), resulting in the inhibition of presoldier production.

Kenji Matsuura - One of the best experts on this subject based on the ideXlab platform.

  • Age-Dependent Increase in Soldier Pheromone of the Termite Reticulitermes speratus
    Journal of Chemical Ecology, 2020
    Co-Authors: Yuki Mitaka, Kenji Matsuura
    Abstract:

    Pheromone communication helps maintaining the sophisticated colony organization in social insects. In the termite Reticulitermes speratus , there are two functionally distinct soldier groups: royal guards and entrance guards. Royal guards protect kings and queens in the innermost part of the nest, whereas entrance guards prevent predators from intruding into the nest at the periphery. A recent study revealed that younger and older soldiers work as royal and entrance guards, respectively. This age-dependent distribution is thought to help workers to recognize where in the nest they are located. However, it is not known whether workers can discriminate the age of soldiers. Here, we show that the abundance of soldier pheromone changes with age and that workers discriminate a soldier’s age by recognizing the pheromone abundance. Gas chromatography–mass spectrometry analysis revealed that the chemical profiles of extracts in three soldier groups of different ages (newly differentiated, royal guard, and entrance guard soldiers) are markedly different. Entrance guard soldiers have the most soldier pheromone among the three age classes. Furthermore, our bioassays suggested that the worker’s movement from chamber to chamber is inhibited only when a soldier with less soldier pheromone is located at the chamber entrance. These results suggest that the soldier pheromone functions as a soldier age indicator and that workers change their behavior depending on the age of the soldier defending the chamber entrance. This study contributes to our understanding of the relationship between aging and pheromone communication in social insects.

  • Chemical identification of an aggregation pheromone in the termite Reticulitermes speratus.
    Scientific reports, 2020
    Co-Authors: Yuki Mitaka, Kenji Matsuura, Shigeru Matsuyama, Nobuaki Mizumoto, Toshiharu Akino
    Abstract:

    Social behaviours in termites are regulated by sophisticated chemical communication systems. The majority of subterranean termites continuously forage for new wood resources to expand their nesting areas; an aggregation pheromone is presumed to regulate this process. However, the chemical components of this pheromone have never been determined. We identified the chemical properties of the aggregation pheromone that signals nestmate presence and induces arrest in the termite Reticulitermes speratus. The results of gas chromatography-mass spectrometry analyses and bioassays indicated that R. speratus worker release the pheromone to their nesting site. The pheromone consists of an aromatic compound (2-phenylundecane), cuticular hydrocarbons (pentacosane and heptacosane), fatty acids (palmitic acid and trans-vaccenic acid), and cholesterol; the pheromone induces long-term aggregation at new nesting and feeding sites. Although 2-phenylundecane alone attracted workers, the combination of all six compounds showed greater arrestant activity than 2-phenylundecane alone. This suggests that 2-phenylundecane functions as an attractant, whereas the remaining five components function as arrestants. Our results indicate that foraging worker termites produce a multi-component aggregation pheromone by combining a volatile hydrocarbon and non-volatile lipids with cuticular hydrocarbons. This pheromone enables rapid, long-lasting aggregation of termite workers, which contributes to efficient feeding and colonisation of new wood. Our work furthers the understanding of chemical communication systems underlying social assembly in social insects.

  • Transcriptomic analysis of epigenetic modification genes in the termite Reticulitermes speratus.
    Insect science, 2018
    Co-Authors: Yuki Mitaka, Eisuke Tasaki, Tomonari Nozaki, Taro Fuchikawa, Kazuya Kobayashi, Kenji Matsuura
    Abstract:

    Eusocial insects display a caste system in which different castes are morphologically and physiologically specialized for different tasks. Recent studies have revealed that epigenetic modifications, including DNA methylation and histone modification, mediate caste determination and differentiation, longevity, and polyethism in eusocial insects. Although there has been a growing interest in the relationship between epigenetic mechanisms and phenotypic plasticity in termites, there is little information about differential expression levels among castes and expression sites for these genes in termites. Here we show royal-tissue-specific expression of epigenetic modification genes in the termite Reticulitermes speratus. Using RNA-seq, we identified 74 genes, including three DNA methyltransferases, seven sirtuins, 48 Trithorax group proteins, and 16 Polycomb group proteins. Among these genes, 15 showed king-specific expression, and 52 showed age-dependent differential expression in kings and queens. Quantitative real-time PCR revealed that DNA methyltransferase 3 is expressed specifically in the king's testis and fat body, whereas some histone modification genes are remarkably expressed in the king's testis and queen's ovary. These findings imply that epigenetic modification plays important roles in the gamete production process in termite kings and queens.

  • caste sex and age dependent expression of immune related genes in a japanese subterranean termite Reticulitermes speratus
    PLOS ONE, 2017
    Co-Authors: Yuki Mitaka, Kazuya Kobayashi, Kenji Matsuura
    Abstract:

    Insects protect themselves from microbial infections through innate immune responses, including pathogen recognition, phagocytosis, the activation of proteolytic cascades, and the synthesis of antimicrobial peptides. Termites, eusocial insects inhabiting microbe-rich wood, live in closely-related family groups that are susceptible to shared pathogen infections. To resist pathogenic infection, termite families have evolved diverse immune adaptations at both individual and societal levels, and a strategy of trade-offs between reproduction and immunity has been suggested. Although termite immune-inducible genes have been identified, few studies have investigated the differential expression of these genes between reproductive and neuter castes, and between sexes in each caste. In this study, we compared the expression levels of immune-related genes among castes, sexes, and ages in a Japanese subterranean termite, Reticulitermes speratus. Using RNA-seq, we found 197 immune-related genes, including 40 pattern recognition proteins, 97 signalling proteins, 60 effectors. Among these genes, 174 showed differential expression among castes. Comparing expression levels between males and females in each caste, we found sexually dimorphic expression of immune-related genes not only in reproductive castes, but also in neuter castes. Moreover, we identified age-related differential expression of 162 genes in male and/or female reproductives. In addition, although R. speratus is known to use the antibacterial peptide C-type lysozyme as an egg recognition pheromone, we determined that R. speratus has not only C-type, but also P-type and I-type lysozymes, as well as other termite species. Our transcriptomic analyses revealed immune response plasticity among all castes, and sex-biased expression of immune genes even in neuter castes, suggesting a sexual division of labor in the immune system of R. speratus. This study heightens the understanding of the evolution of antimicrobial strategies in eusocial insects, and of sexual roles in insect societies as a whole.

  • Colony-dependent sex differences in protozoan communities of the lower termite Reticulitermes speratus (Isoptera: Rhinotermitidae)
    Ecological Research, 2016
    Co-Authors: Tatsuya Inagaki, Kenji Matsuura
    Abstract:

    In many animals, sex differences in hormones, behavior, and immunity lead to differences in their gut microbial communities. One of the best-known examples of mutualistic symbiosis is that between lower termites and their intestinal protozoa. Although differences in the protozoan communities of different castes have been studied in lower termites, nothing is known about the sex differences in protozoan communities in neuter castes. Here, we show that termite workers have different protozoan communities according to sex depending on the colony. We investigated the communities of symbiotic protozoa living in lower termites, Reticulitermes speratus, and how they are affected by sex and caste. Workers had the largest numbers of protozoa, followed by soldiers, whereas reproductives (primary kings and secondary queens) had no protozoa. Workers showed colony-dependent sex differences in the total abundance of protozoa, whereas soldiers showed no such sex differences. There were significant sex effect and/or interaction effect between colony and sex in abundances of five species of protozoa in workers. Workers also showed significant sex differences and/or colony-dependent sex differences in proportion of six species of protozoa. These may result in sex differences in the host–symbiont interaction due to physiological or behavioral sex differences in workers that have not been recognized previously. This study has an important implication: although workers are not engaged in reproduction, their potential sex difference may affect various aspects of social interactions.

Shigeharu Moriya - One of the best experts on this subject based on the ideXlab platform.

  • Screening and evolution of a novel protist xylose isomerase from the termite Reticulitermes speratus for efficient xylose fermentation in Saccharomyces cerevisiae
    Biotechnology for biofuels, 2017
    Co-Authors: Satoshi Katahira, Moriya Ohkuma, Shigeharu Moriya, Nobuhiko Muramoto, Risa Nagura, Nobuki Tada, Noriko Yasutani, Toru Onishi, Kenro Tokuhiro
    Abstract:

    The yeast Saccharomyces cerevisiae, a promising host for lignocellulosic bioethanol production, is unable to metabolize xylose. In attempts to confer xylose utilization ability in S. cerevisiae, a number of xylose isomerase (XI) genes have been expressed heterologously in this yeast. Although several of these XI encoding genes were functionally expressed in S. cerevisiae, the need still exists for a S. cerevisiae strain with improved xylose utilization ability for use in the commercial production of bioethanol. Although currently much effort has been devoted to achieve the objective, one of the solutions is to search for a new XI gene that would confer superior xylose utilization in S. cerevisiae. Here, we searched for novel XI genes from the protists residing in the hindgut of the termite Reticulitermes speratus. Eight novel XI genes were obtained from a cDNA library, prepared from the protists of the R. speratus hindgut, by PCR amplification using degenerated primers based on highly conserved regions of amino acid sequences of different XIs. Phylogenetic analysis classified these cloned XIs into two groups, one showed relatively high similarities to Bacteroidetes and the other was comparatively similar to Firmicutes. The growth rate and the xylose consumption rate of the S. cerevisiae strain expressing the novel XI, which exhibited highest XI activity among the eight XIs, were superior to those exhibited by the strain expressing the XI gene from Piromyces sp. E2. Substitution of the asparagine residue at position 337 of the novel XI with a cysteine further improved the xylose utilization ability of the yeast strain. Interestingly, introducing point mutations in the corresponding asparagine residues in XIs originated from other organisms, such as Piromyces sp. E2 or Clostridium phytofermentans, similarly improved xylose utilization in S. cerevisiae. A novel XI gene conferring superior xylose utilization in S. cerevisiae was successfully isolated from the protists in the termite hindgut. Isolation of this XI gene and identification of the point mutation described in this study might contribute to improving the productivity of industrial bioethanol.

  • the gh26 β mannanase rsman26h from a symbiotic protist of the termite Reticulitermes speratus is an endo processive mannobiohydrolase heterologous expression and characterization
    Biochemical and Biophysical Research Communications, 2014
    Co-Authors: Hikaru Tsukagoshi, Katsuhiko Kitamoto, Shigeharu Moriya, Akihiko Nakamura, Takuya Ishida, Masato Otagiri, Masahiro Samejima, Kiyohiko Igarashi, Manabu Arioka
    Abstract:

    Symbiotic protists in the gut of termites are prominent natural resources for enzymes involved in lignocellulose degradation. Here we report expression, purification, and biochemical characterization of a glycoside hydrolase family 26 mannanase RsMan26H from the symbiotic protist of the lower termite, Reticulitermes speratus. Biochemical analysis of RsMan26H demonstrates that this enzyme is an endo-processive mannobiohydrolase producing mannobiose from oligo- and polysaccharides, followed by a minor accumulation of oligosaccharides larger than mannobiose. To our knowledge, this is the first report describing the unique mannobiohydrolase enzyme from the eukaryotic origin.

  • structural and biochemical analyses of glycoside hydrolase family 26 β mannanase from a symbiotic protist of the termite Reticulitermes speratus
    Journal of Biological Chemistry, 2014
    Co-Authors: Hikaru Tsukagoshi, Shigeharu Moriya, Akihiko Nakamura, Takuya Ishida, Masato Otagiri, Masahiro Samejima, Kiyohiko Igarashi, Kouki K Touhara, Shinya Fushinobu, Katsuhiko Kitamoto
    Abstract:

    Termites and their symbiotic protists have established a prominent dual lignocellulolytic system, which can be applied to the biorefinery process. One of the major components of lignocellulose from conifers is glucomannan, which comprises a heterogeneous combination of β-1,4-linked mannose and glucose. Mannanases are known to hydrolyze the internal linkage of the glucomannan backbone, but the specific mechanism by which they recognize and accommodate heteropolysaccharides is currently unclear. Here, we report biochemical and structural analyses of glycoside hydrolase family 26 mannanase C (RsMan26C) from a symbiotic protist of the termite Reticulitermes speratus. RsMan26C was characterized based on its catalytic efficiency toward glucomannan, compared with pure mannan. The crystal structure of RsMan26C complexed with gluco-manno-oligosaccharide(s) explained its specificities for glucose and mannose at subsites −5 and −2, respectively, in addition to accommodation of both glucose and mannose at subsites −3 and −4. RsMan26C has a long open cleft with a hydrophobic platform of Trp94 at subsite −5, facilitating enzyme binding to polysaccharides. Notably, a unique oxidized Met85 specifically interacts with the equatorial O-2 of glucose at subsite −3. Our results collectively indicate that specific recognition and accommodation of glucose at the distal negative subsites confers efficient degradation of the heteropolysaccharide by mannanase.

  • Heterologous Expression and Characterization of a Glycoside Hydrolase Family 45 endo-β-1,4-Glucanase from a Symbiotic Protist of the Lower Termite, Reticulitermes speratus
    Applied Biochemistry and Biotechnology, 2013
    Co-Authors: Masato Otagiri, Crisanto M. Lopez, Manabu Arioka, Katsuhiko Kitamoto, Toshiaki Kudo, Shigeharu Moriya
    Abstract:

    The termite symbiotic system is one of the efficient lignocellulose degradation systems. We tried to express and characterize a novel cellulolytic enzyme from this system. Here, we report the isolation of an endo -β-1,4-glucanase gene homolog of glycoside hydrolase family 45 from a symbiotic protistan community of Reticulitermes speratus. Heterologous expression of this gene was performed using the expression system of Aspergillus oryzae . Analysis of enzymatic properties revealed 786 μmol/min/mg protein in specific activity, a V _max of 833.0 units/mg protein, and a K _m value of 2.58 mg/ml with carboxymethyl cellulose as the substrate. Thin-layer chromatography analysis showed that RsSymEG2 produces cellobiose from cellodextrins larger than cellohexaose. This enzyme showed high specific activity like other endo -β-1,4-glucanases from the symbiotic system of termites. It means that the termite symbiotic system is a good resource for highly active endo -β-1,4-glucanases.

  • Heterologous Expression and Characterization of an Endoglucanase from a Symbiotic Protist of the Lower Termite, Reticulitermes speratus
    Applied biochemistry and biotechnology, 2009
    Co-Authors: Nemuri Todaka, Crisanto M. Lopez, Tetsushi Inoue, Kanako Saita, Jun-ichi Maruyama, Manabu Arioka, Katsuhiko Kitamoto, Toshiaki Kudo, Shigeharu Moriya
    Abstract:

    RsSymEG, an endoglucanase of glycosyl hydrolase family (GHF) 7 encoded by a transcript isolated from the symbiotic protist of the termite Reticulitermes speratus, is expressed in Aspergillus oryzae. Interestingly, purified RsSymEG1 has a relatively higher specific activity (603 μmol min−1 mg−1 protein) and V max value (769.6 unit/mg protein) than previously reported data for GHF7 endoglucanase of Trichoderma ressei. It also has the same K m value (1.97 mg/ml) with Clostridium cellulolyticum enzymes that contain cellulose binding module, a property indicative of high affinity to substrate, though no cellulose binding module is found within it. Thin-layer chromatography analysis revealed that RsSymEG1 preferentially hydrolyzes the β-1,4-cellulosic linkage of cellodextrins into cellobiose and glucose.