「せんだんご」はサツマイモを原料とした長崎県対馬地方固有の伝統発酵食品である．せんだんごはスライスまたは破砕したサツマイモを数ヶ月間発酵させた後，多量の水で洗浄して浮遊物や着色物質が除かれた白色沈殿物を丸め団子状とし，ヒトの鼻形に成型し，乾燥させたものである．せんだんごを基に作られる「ろくべえ麺」は，原料であるサツマイモからは想像し得ないコンニャクに似た独特な食感を有し，この食感は原料サツマイモ粉からは得られないとされている．せんだんご製造工程中には糸状菌などの繁殖が見られ，これらの微生物はデンプンや繊維質を部分的に分解することでろくべえ麺の食感形成に関与していると考えられる．しかし，せんだんご製造に関わる微生物について，研究報告がこれまでに無いのが現状である．

そこで，本研究では4 年間にわたり現地を調査し，培養法によりせんだんご製造工程中の微生物叢を調べた．その結果，せんだんご製造工程から多くの微生物が分離され，主要微生物群は，糸状菌ではMucor 属，Penicillium 属，酵母では Candida 属，一般細菌ではBacillus 属，Paenibacillus 属であった．

せんだんごに含まれるデンプン及び繊維質は，原料サツマイモに含まれるそれらと比べ，部分的に分解されており，繊維質の中でも減少量が多いペクチンに着目した．これを指標に，分離株の中からデンプン及びペクチン双方の分解能を持つ微生物を選抜した．その結果，Mucor 属及びPenicillium 属において両分解能を確認した．これらの糸状菌は生産農家や年度に関わらず見出せることから，せんだんごの発酵に欠かせない微生物であることが示唆された．

長崎県対馬地方には，サツマイモを原料とした固有の伝統発酵食品「せんだんご」がある．せんだんごを基に作られる「ろくべえ麺」は，原料であるサツマイモからは想像し得ないコンニャクに似た独特な食感を有する．この独特な食感は，原料サツマイモ粉からは得られず，発酵によりサツマイモのデンプンと繊維質（特にペクチンの減少量が多い）が部分的に分解されたことに起因し，それらの分解に関わる微生物は製造農家や年度に関わらず製造工程中に生息しており，デンプンやペクチンの両分解能を有する糸状菌であるMucor 属やPenicillium 属であると報告されている．しかし，これら糸状菌がサツマイモのデンプンやペクチンに与える影響については，不明のままである． 　

そこで，本研究ではMucor 属やPenicillium 属の発酵によるデンプンやペクチンの分子量変化を検討した．はじめにせんだんごのデンプンやペクチンは原料サツマイモと比較して低分子量化していることを明らかとした．また，分離株のうち，P.echinulatum 38-1 株とP. expansum 13-3 株が，デンプンやペクチンを低分子量化することを明らかとした．P. echinulatam 38-1 株及びP. expansum 13-3 株を用いて，せんだんごを試作し，物性を評価した．その結果，試作せんだんごより調製したろくべえ麺の物性は，対馬産せんだんごから調製したろくべえ麺と同様の解析結果を得た．さらに，P. echinulatam 38-1 株及びP. expansum 13-3 株を用いて製造した試作せんだんごのデンプンとペクチンの分子量変化を検討した結果，両試作せんだんごのデンプンとペクチンは，対馬産せんだんごと同様に低分子量化していることを確認した．　

以上のことから，せんだんご製造工程中に生息するP. echinulatam やP. expansum はろくべえ麺独特な食感形成に関与する主要微生物であることが示唆された．

This review highlights the major milestones in the growth of the Japan Society for Microbial Systematics (JSMS) over the past 33 years from its birth at Ubako Onsen in Hakone in October 1980 to its 33rd Annual Meeting at Takayama Green Hotel in Takayama in November 2013. The history of JSMS was divided into four ages based on the name changes of the Society: “The Group Meeting of Chemotaxonomy of Microorganisms” Age (1980-1984), “The Society for Microbial Chemotaxonomy” Age (1985-1994), “The Society for Microbial Taxonomy” Age (1995-2002), and “The Japan Society for Microbial Systematics” Age (2003-2013). With changes in the dynamics of science and the development of related methodologies, the core of discussions at the respective meetings changed from microbial chemotaxonomy in the 1980s to microbial molecular taxonomy/systematics in the 1990s and 2000s. In recent meetings, the theme “How to put the genome information to practical use in microbial systematics,” which reflects the Genomics Era, was repeatedly discussed. During the past 33 years, the following were held: special lectures (34 talks, with 12 invited speakers from overseas; keynote lecture (1 talk); symposia (5 themes, 27 talks); mini-symposia (2 themes, 5 talks); theme-oriented discussions (16 themes, 26 talks); workshops (3 themes, 7 talks); oral presentations (278 talks; of these, all talks were presented in English at the 2nd meeting in 1981, 3rd meeting in 1983, 8th meeting in 1988, and 20th meeting in 2000), and poster presentations (76 titles). Furthermore, 5 talks (with 3 invited speakers from overseas) at Symposium S-1“ Current advances in the species concept problems of microorganisms ―definitions, methodologies and practical applications” in the 10th International Conference on Culture Collections (ICCC-10) in Tsukuba on October 11, 2004, are included in JSMS’s contributions. The aims and goals, including the raison d’etre, of JSMS, have been mentioned and briefly discussed in this review. In addition, the author’s opinions or impressions regarding the past 33 years of the Society, including a few future perspectives, have been presented.

Actinobacteria are Gram-stain-positive bacteria with a variety of morphologies. They produce various secondary metabolites and are therefore treated as distinct from other bacteria. Until the early 1970s actinobacteria were classified mainly on the basis of their morphological features, but they are currently classified by a combination of their chemotaxonomic characteristics and phylogenetic relationships based on 16S rRNA gene sequences. However, this classification is problematic, because the phenotypic diversity of actinobacteria has led to excessive division of genera and species. Recent taxonomic studies using whole-genome sequences have resulted in more reliable phylogenetic relationships than those based on 16S rRNA gene sequences and should therefore facilitate the reclassification of known species. Furthermore, recent increases in the sophistication of analytical instruments are enabling more detailed chemotaxonomic characterization and could lead to the discovery of new taxonomic indicators. Therefore, more appropriate classification systems will likely be built through a combination of detailed chemotaxonomic characterization and phylogenetic analysis based on whole-genome sequences.

In 1872, bacteria were classified by Ferdinand J. Cohn, a botanist and microbiologist, for the first time in the world. This classification was based on morphology. Cohn’s concept was reasonable to a point, but it soon became unsuitable because bacteria have quite low levels of morphological variation. At the beginning of the 20th century, Sigurd Orla- Jensen, a biochemist, proposed a new taxonomic system grounded in physiology, and by half a century later modern bacterial taxonomy based on polyphasic comparison of morphological, physiological, and biochemical characteristics had been established. At the end of the 20th century, bacterial taxonomy entered a new epoch thanks to the great insight of the molecular evolutionist Carl R. Woese. The ribosomal RNA that he noticed turned out to be a molecule useful for revealing phylogenetic relationships, not only among all living organisms but also within bacteria. Use of this excellent evolutionary marker also allowed scientists other than bacterial taxonomists to study bacterial classification and identification, thus accelerating progress in bacterial taxonomy. Today, a new era is again about to begin in this intersection of bacteriology, as a result of rapid progress in the development of DNA sequencing technology and computer science.

The past 20 years have seen great progress in prokaryotic systematics. Application of genetic information such as 16S rDNA sequencing has been the greatest driving force behind these achievements. DNA–DNA hybridization is still considered a gold standard for species delineation, but phenotypic characterization (including characterization of cultural behavior characteristics) is still required for bacterial species description. In contrast, molecular approaches have brought great progress in microbial ecology. One of these advances is the analysis of microbial consortia without the need for culture. As a result, some taxonomic discordance has arisen between microbial taxonomy and microbial ecology. From this perspective, microbial ecologists have put forward suggestions for prokaryotic taxonomy. Furthermore, recent advances in sequencing technology have resulted in easy access to genomic information on microbes, even in the environment. The application of advanced bioinformatics techniques to genome sequencing now allows for a genotype-to-phenotype approach, which can reveal phenotypic information on microbes of interest without the need for culture. These amazing advances in molecular biology and informatics will provide a paradigm shift in prokaryotic taxonomy and the concept of species in the near future.

Aspergillus fumigatus is distributed worldwide in soil, air, foods, feeds, compost, and human habitats. Aspergillus fumigatus and its related species, including the genus Neosartorya, which is a teleomorph of Aspergillus, are the most important causative agents of aspergillosis. These species belong to Aspergillus section Fumigati. Conidiogenesis and conidial ornamentation are important morphological characters for distinguishing Aspergillus species. The teleomorph of Aspergillus has various ascospore ornamentations, and these are characteristic of species discrimination.

Rules for the systematic biology of Aspergillus were suggested in 2007, and since then the partial β-tubulin, calmodulin, actin, and RNA polymerase genes and the internal transcribed spacer (ITS) region have been used for the taxonomy of Aspergillus. The β-tubulin and calmodulin genes, in particular, have been well analyzed in Aspergillus and its related genera.

The correlations among molecular phylogenetics and phenotypic characters have been investigated well in Aspergillus. Molecular phylogenetics has become a useful tool for distinguishing species of Aspergillus and its related genera, and many new species have been discovered and described since 2007.

In section Fumigati, several species (especially A. udagawae and A. viridinutans) show within-species diversity of DNA sequences. Recently, several researchers have reevaluated A. viridinutans by using a mating test. As a result, A. viridinutans has been separated into seven species on the basis of conidial or ascospore morphology. Application of systematic biology has promoted variation in the modern taxonomy of Aspergillus.