Publications

4618

Apart from sharing the basic cellular features of otherBacteria, the cyanobacteria possess unique and diagnostic characteristics that will be briefly described here, but less extensively than in the 1989 edition ofBergey's Manual of Systematic Bacteriology. The cell wall in cyanobacteria is of a Gram‐negative type. Cell division in most unicellular and colonial cyanobacteria and some filamentous forms is by binary fission. Regarding cell exterior and motility, fimbriae (or pili) occur abundantly with diverse patterns in many cyanobacteria. Although not all thylakoids in cyanobacteria appear to be invaginations of the cytoplasmic membrane, there are orderly “attachment points” or “thylakoid centers” associated with the periphery of the cytoplasm or the cytoplasmic membrane. In the cytoplasm of cyanobacteria there are many other components and “inclusions”, most of which can be visualized readily using various preparative techniques for transmission electron microscopy. They include glycogen granules, cyanophycin granules, carboxysomes (polyhedral bodies), polyphosphate (volutin) granules, and gas vacuoles. Heterocysts, akinetes, and hormogonia are some of the specialized cells and differentiation in Cyanobacteria. The chief physiological/biochemical characteristic of cyanobacteria, distinguishing them from all other procaryotes, is the dual photosystem that allows the use of H2O as photoreductant with the consequent liberation of O2. Two courses for the delimitation of genera have been followed by cyanobacterial specialists: (a) to retain “small” genera or (b) to gather many species into fewer genera.Cyanobacteria / General Characteristics of the Cyanobacteria

Phy.to.plas'ma. Gr. masc. n.phytosa plant; Gr. neut. n.plasmasomething formed or molded, a form.Tenericutes / Mollicutes / Acholeplasmatales / incertae Sedis ‐ Family II / “Candidatus Phytoplasma”Phytoplasmas (Sears and Kirkpatrick, 1994) are wall‐less, nutritionally fastidious, phytopathogenic prokaryotes 0.2–0.8 µm in diameter that morphologically resemble members of theMollicutes. Sequencing of nearly full‐length PCR‐amplified 16S rRNA genes (Gundersen et al., 1994; Namba et al., 1993; Seemüller et al., 1994), combined with earlier studies (Kuske and Kirkpatrick, 1992b; Lim and Sears, 1989), provided the first comprehensive phylogeny of the organisms and showed that they constitute a unique, monophyletic clade within theMollicutes. These organisms are most closely related to members of the genusAcholeplasmawithin theAnaeroplasmaclade as defined by Weisburg et al. (1989). Sustained culture in cell‐free media has not yet been demonstrated for any phytoplasma. Their genome sizes have been estimated to range from 530 to 1350 kb, and the G+C content of phytoplasma DNA is about 23–30 mol%. The presence of a characteristic oligonucleotide sequence in the 16S rRNA gene, CAA GAY BAT KAT GTK TAG CYG GDC T, and standard codon usage indicate that phytoplasmas represent a distinct taxon for which the name “CandidatusPhytoplasma” has been adopted by specialists in the molecular biology and pathogenicity of these and similar phytopathogenic organisms (IRPCM Phytoplasma/Spiroplasma Working Team – Phytoplasma Taxonomy Group, 2004). At present, the designation “Candidatus” must still be used for new types.

Abstract Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Candidatus Paracaedibacter is: preferred name (not correct name) (last update, February 2025) * . LPSN classification: Bacteria / Pseudomonadati / Pseudomonadota / Alphaproteobacteria / Holosporales / Candidatus Paracaedibacteraceae / Candidatus Paracaedibacter Candidatus Paracaedibacter could not be recovered in GTDB ** . * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ). Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776

Abstract A.my.co.la.top'sis. N.L. fem. n. Amycolata genus belonging to the order Actinomycetales ; Gr. fem. n. opsis aspect, appearance; N.L. fem. n. Amycolatopsis that which appears similar to Amycolata . Aerobic to facultatively anaerobic , Gram‐stain‐positive , non‐acid‐fast , nonmotile , catalase‐positive actinomycetes that form branching substrate hyphae which fragment into squarish and rod‐shaped elements . When formed , aerial hyphae may be sterile or differentiate into chains of smooth‐walled , squarish to ellipsoidal spore‐like structures . Chemo‐organotrophic to facultatively autotrophic. Grows on a broad range of organic and synthetic media. Mesophilic or thermophilic. Whole‐organism hydrolysates are rich in meso ‐2 , 6‐diaminopimelic acid , arabinose , and galactose . The peptidoglycan is of the A1γ type. Muramic acid moieties are N ‐acetylated. The diagnostic phospholipid is phosphatidylethanolamine ( with or without phosphatidylmethylethanolamine ) or phosphatidylmethylethanolamine with variable occurrence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides; contains complex mixtures of saturated and branched chain fatty acids . Does not contain mycolic acids. The phylogenetic position of Amycolatopsis , as determined by 16S rRNA gene sequence analysis, is in the family Pseudonocardiaceae . Common in arid soils but has also been isolated from activated sludge, equine placentas, and from clinical and plant material. DNA G + C content ( mol %): 66–75 ( T m ; HPLC). Type species : Amycolatopsis orientalis (Pittenger and Brigham 1956) Lechevalier, Prauser, Labeda and Ruan 1986, 35 VP . Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Amycolatopsis is: correct name (last update, February 2025) * . LPSN classification: Bacteria / Bacillati / Actinomycetota / Actinomycetes / Pseudonocardiales / Pseudonocardiaceae / Amycolatopsis The genus Amycolatopsis can also be recovered in the Genome Taxonomy Database (GTDB) as g__Amycolatopsis (version v220) ** . GTDB classification: d__Bacteria / p__Actinomycetota / c__Actinomycetes / o__Mycobacteriales / f__Pseudonocardiaceae / g__Amycolatopsis * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ). Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776

ABSTRACT Thermoproteales (phylum Crenarchaeota ) populations are abundant in high-temperature (>70°C) environments of Yellowstone National Park (YNP) and are important in mediating the biogeochemical cycles of sulfur, arsenic, and carbon. The objectives of this study were to determine the specific physiological attributes of the isolate Pyrobaculum yellowstonensis strain WP30, which was obtained from an elemental sulfur sediment (Joseph's Coat Hot Spring [JCHS], 80°C, pH 6.1, 135 μM As) and relate this organism to geochemical processes occurring in situ . Strain WP30 is a chemoorganoheterotroph and requires elemental sulfur and/or arsenate as an electron acceptor. Growth in the presence of elemental sulfur and arsenate resulted in the formation of thioarsenates and polysulfides. The complete genome of this organism was sequenced (1.99 Mb, 58% G+C content), revealing numerous metabolic pathways for the degradation of carbohydrates, amino acids, and lipids. Multiple dimethyl sulfoxide-molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, were identified. Pathways for the de novo synthesis of nearly all required cofactors and metabolites were identified. The comparative genomics of P. yellowstonensis and the assembled metagenome sequence from JCHS showed that this organism is highly related (∼95% average nucleotide sequence identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide an important foundation for developing an understanding of the distribution and function of these populations in YNP.