The recent explosion of newly described species of Nocardia results from the impact in the last decade of newer molecular technology, including PCR restriction enzyme analysis and 16S rRNA sequencing. These molecular techniques have revolutionized the identification of the nocardiae by providing rapid and accurate identification of recognized nocardiae and, at the same time, revealing new species and a number of yet-to-be-described species. There are currently more than 30 species of nocardiae of human clinical significance, with the majority of isolates being N. nova complex, N. abscessus, N. transvalensis complex, N. farcinica, N. asteroides type VI (N. cyriacigeorgica), and N. brasiliensis. These species cause a wide variety of diseases and have variable drug susceptibilities. Accurate identification often requires referral to a reference laboratory with molecular capabilities, as many newer species are genetically distinct from established species yet have few or no distinguishing phenotypic characteristics. Correct identification is important in deciding the clinical relevance of a species and in the clinical management and treatment of patients with nocardial disease. This review characterizes the currently known pathogenic species of Nocardia, including clinical disease, drug susceptibility, and methods of identification.

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Clinical and Laboratory Features of the Nocardia spp. Based on Current Molecular Taxonomy

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in the nomenclature of prokaryotes. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.

List of new names and new combinations previously effectively, but not validly, published.

Indole-3-acetic acid (IAA) is an important phytohormone with the capacity to control plant development in both beneficial and deleterious ways. The ability to synthesize IAA is an attribute that many bacteria including both plant growth-promoters and phytopathogens possess. There are three main pathways through which IAA is synthesized; the indole-3-pyruvic acid, indole-3-acetamide and indole-3-acetonitrile pathways. This chapter reviews the factors that effect the production of this phytohormone, the role of IAA in bacterial physiology and in plant–microbe interactions including phytostimulation and phytopathogenesis.

Indole-3-acetic acid in plant–microbe interactions

Topley and Wilson's Microbiology and Microbial Infections

DNA base composition was determined by reversed-phase high-performance liquid chromatography (HPLC). DNA was hydrolysed into nucleosides with nuclease P1 and bacterial alkaline phosphatase. The mixture of nucleosides was applied to HPLC without any further purification. One determination by chromatography needed 2 μg of hydrolysed nucleosides and took only 8 min. The relative standard error of nucleoside analysis was less than 1%. The system described here gives a direct and precise method for determining DNA base composition.

Research letterDetermination of DNA base composition by reversed-phase high-performance liquid chromatography

An investigation was conducted to explore the effect of the phytohormone indole-3-acetic acid (IAA) on cellular differentiation in streptomycetes. A total of 21 Streptomyces strains known to produce antibiotics were tested. IAA (1–20 μg/ml) in Bennett’s agar markedly stimulated aerial mycelium formation and antibiotic production in 12 and 13 test strains, respectively. The stimulating effect of IAA was confirmed even in a submerged culture: production of an anthracycline group antibiotic, rhodomycin, by S. purpurascens NBRC 13077 cultured in oatmeal-MYM broth, was markedly enhanced by addition of IAA (20 μg/ml). mRNA differential display (RT-PCR) analysis revealed that expression of rdmA, rdmB, rdmC, rdmD and rdmE, all genes involved in rhodomycin production, was up-regulated by IAA treatment in S. purpurascens. These results suggest that IAA may act as a common regulating agent for sporulation and secondary metabolism in streptomycetes.

Stimulatory effect of indole-3-acetic acid on aerial mycelium formation and antibiotic production in Streptomyces spp.

Distribution of the sulfite resistance gene SSU1-R and the variation in its promoter region in wine yeasts.

Some strains of Saccharomyces cerevisiae form a biofilm called a “flor” on the surface of wine after ethanolic fermentation, but the molecular mechanism of flor formation by the wild-type flor strain involved in wine making is not clear. Previously, we found that expression of the C-terminally truncated form of NRG1 (NRG1 1-470) on a multicopy plasmid increases the hydrophobicity of the cell surface, conferring flor formation on the non-flor laboratory strain. Here we show that in Ar5-H12, a wild-type flor haploid strain, flor formation is regulated by NRG1 1-470. Moreover, the disruptant of the wild-type flor diploid strain (Δflo11/Δflo11) show a weak ability to form the flor. The expression of FLO11 is always high in the wild-type flor strain, regardless of carbon source. Thus FLO11 is primary factor for wild-type flor strains. Furthermore, the disruptant (Δflo11) shows lower hydrophobicity of cell surface than the wild type. However, the hydrophobicity of the wild-type flor strains grown in ethanol med...

https://www.tandfonline.com/doi/pdf/10.1271/bbb.70.660

FLO11 Is the Primary Factor in Flor Formation Caused by Cell Surface Hydrophobicity in Wild-Type Flor Yeast

The flor strains of Saccharomyces cerevisiae form a flor on the surface of wine after alcoholic fermentation. High hydrophobicity of the cell surface is suggested to be important for flor formation by the flor wine yeasts. However, the molecular mechanism of flor formation is not clear. We found that expression of C-terminal deleted NRG1 lacking its two C2H2 zinc finger motifs (NRG11–470) on the multicopy plasmid conferred the ability to form a flor to a non-flor laboratory strain. The cell surface hydrophobicity of NRG11–470 was higher than of the non-flor strain. Disruption of the Nrg1p-repressed gene FLO11, which encodes a cell surface glycoprotein that functions as a flocculin or an adhesin, abolished flor formation. Moreover, expression of FLO11 on a multicopy plasmid could also cause flor formation. These results indicate that FLO11 is essential for flor formation by NRG11–470. In addition, the results suggest that the C-terminal truncated form of Nrg1p exerts a dominant negative effect on FLO11 repression, resulting in FLO11 expression and, thus, flor formation.

FLO11 is essential for flor formation caused by the C-terminal deletion of NRG1 in Saccharomyces cerevisiae

An actinomycete strain, IR73-Li102T, was isolated from a lichen sample obtained from Iriomote Island, Japan, and subsequently characterized using a polyphasic approach. Comparative 16S rRNA gene sequence analysis revealed that strain IR73-Li102T had the highest sequence similarities with Actinomycetospora chiangmaiensis YIM 0006T (98.3%), A. corticola 014-5T (98.1%) and A. rishiriensis RI109-Li102T (98.0%). However, DNA–DNA hybridization assays, as well as physiological and biochemical analyzes, showed that strain IR73-Li102T could be clearly differentiated from its closest phylogenetic relatives. The strain contained meso-diaminopimelic acid, and arabinose and galactose were present in whole-cell hydrolysates. The predominant menaquinone was MK-8(H4), and the diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and diphosphatidylglycerol. The major cellular fatty acid was iso-C16:0 (58%). The chemotaxonomic properties of strain IR73-Li102T were consistent with those shared by members of the genus Actinomycetospora. On the basis of the phenotypic features and DNA–DNA hybridization data, strain IR73-Li102T (= NBRC 106365T = KCTC 19783T) represents a novel species of the genus Actinomycetospora, for which the name Actinomycetospora iriomotensis sp. nov. is proposed.

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Youji Nakagawa

Papers

Stimulatory effect of indole-3-acetic acid on aerial mycelium formation and antibiotic production in Streptomyces spp.

Distribution of the sulfite resistance gene SSU1-R and the variation in its promoter region in wine yeasts.

FLO11 Is the Primary Factor in Flor Formation Caused by Cell Surface Hydrophobicity in Wild-Type Flor Yeast

FLO11 is essential for flor formation caused by the C-terminal deletion of NRG1 in Saccharomyces cerevisiae

Actinomycetospora iriomotensis sp. nov., a novel actinomycete isolated from a lichen sample