Rhodobium pfennigii sp. nov., a phototrophic purple non-sulfur bacterium with unusual bacteriochlorophyll a antennae, isolated from a brackish microbial mat on Rangiroa atoll, French Polynesia

Afifella aestuarii sp. nov., a phototrophic bacterium

An oval- to rod-shaped, motile, Gram-stain-negative, oxidase-positive, catalase-negative, pink-coloured phototrophic bacterium (designated as strain JA968^T) was isolated from an estuary near Pata, Gujarat, India. Cells had an intracytoplasmic membrane architecture as lamellae and divided by budding. Strain JA968^T had bacteriochlorophyll-a and spirilloxanthin series carotenoids as photosynthetic pigments. The strain exhibited photolithoautotrophic, photoorganoheterotrophic and chemoorganoheterotrophic growth modes and required thiamine as a growth factor. Strain JA968^T had C_18 : 1ω7c/C_{18  : 1}ω6c as the predominant fatty acid with ubiquinone-10 (Q-10) and menaquinone-10 (MK-10) forming the quinone composition. The genomic DNA G+C content of the strain was 63.5 mol%. Pairwise comparison of 16S rRNA gene sequences showed that strain JA968^T was highly similar to Afifella marina DSM 2698^T (99.9 %) and Afifella pfennigii DSM 17143^T (98.4 %). The average nucleotide identity values were 92 % between strain JA968^T and A. marina DSM 2698^T, and 78 % between strain JA968^T and A. pfennigii DSM 17143^T. The digital DNA-DNA hybridization values between strain JA968^T and A. marina and A. pfennigii were 49 and 19 %, respectively. The genomic distinction was also supported by differences in phenotypic and chemotaxonomic characteristics. We propose that strain JA968^T represents a new species of the genus Afifella with the name Afifella aestuarii sp. nov. The type strain is JA968^T (=KCTC 15634^T=NBRC 113338^T).

Jellyfish Life Stages Shape Associated Microbial Communities, While a Core Microbiome Is Maintained Across All

The key to 650 million years of evolutionary success in jellyfish is adaptability: with alternating benthic and pelagic generations, sexual and asexual reproductive modes, multitudes of body forms and a cosmopolitan distribution, jellyfish are likely to have established a plenitude of microbial associations. Here we explored bacterial assemblages in the scyphozoan jellyfish Chrysaora plocamia (Lesson 1832). Life stages involved in propagation through cyst formation, i.e., the mother polyp, its dormant cysts (podocysts), and polyps recently excysted (excysts) from podocysts – were investigated. Associated bacterial assemblages were assessed using MiSeq Illumina paired-end tag sequencing of the V1V2 region of the 16S rRNA gene. A microbial core-community was identified as present through all investigated life stages, including bacteria with closest relatives known to be key drivers of carbon, nitrogen, phosphorus, and sulfur cycling. Moreover, the fact that half of C. plocamia’s core bacteria were also present in life stages of the jellyfish Aurelia aurita, suggests that this bacterial community might represent an intrinsic characteristic of scyphozoan jellyfish, contributing to their evolutionary success.

Restricted Localization of Photosynthetic Intracytoplasmic Membranes (ICMs) in Multiple Genera of Purple Nonsulfur Bacteria

In bacteria and eukaryotes alike, proper cellular physiology relies on robust subcellular organization. For the phototrophic purple nonsulfur bacteria (PNSB), this organization entails the use of a light-harvesting, membrane-bound compartment known as the intracytoplasmic membrane (ICM). Here we show that ICMs are spatially and temporally localized in diverse patterns among PNSB. We visualized ICMs in live cells of 14 PNSB species across nine genera by exploiting the natural autofluorescence of the photosynthetic pigment bacteriochlorophyll (BChl). We then quantitatively characterized ICM localization using automated computational analysis of BChl fluorescence patterns within single cells across the population. We revealed that while many PNSB elaborate ICMs along the entirety of the cell, species across as least two genera restrict ICMs to discrete, nonrandom sites near cell poles in a manner coordinated with cell growth and division. Phylogenetic and phenotypic comparisons established that ICM localization and ICM architecture are not strictly interdependent and that neither trait fully correlates with the evolutionary relatedness of the species. The natural diversity of ICM localization revealed herein has implications for both the evolution of phototrophic organisms and their light-harvesting compartments and the mechanisms underpinning spatial organization of bacterial compartments.IMPORTANCE Many bacteria organize their cellular space by constructing subcellular compartments that are arranged in specific, physiologically relevant patterns. The purple nonsulfur bacteria (PNSB) utilize a membrane-bound compartment known as the intracytoplasmic membrane (ICM) to harvest light for photosynthesis. It was previously unknown whether ICM localization within cells is systematic or irregular and if ICM localization is conserved among PNSB. Here we surveyed ICM localization in diverse PNSB and show that ICMs are spatially organized in species-specific patterns. Most strikingly, several PNSB resolutely restrict ICMs to regions near the cell poles, leaving much of the cell devoid of light-harvesting machinery. Our results demonstrate that bacteria of a common lifestyle utilize unequal portions of their intracellular space to harvest light, despite light harvesting being a process that is intuitively influenced by surface area. Our findings therefore raise fundamental questions about ICM biology and evolution.

Amphiplicatus metriothermophilus gen. nov., sp. nov., a thermotolerant alphaproteobacterium isolated from a hot spring

A thermotolerant, Gram-strain-negative, non-spore-forming and strictly aerobic bacterium, designated GU51(T), was isolated from Guhai hot spring in Jimsar county, Xinjiang province, north-west China. Each cell of strain GU51(T) consisted of an oval body and two symmetrical long (3-6 µm) prosthecae. The strain moved by polar flagellum. Oxidase and catalase were produced. Strain GU51(T) grew within the ranges of 37-65 °C (optimum 48-50 °C), 0.5-7.5% (w/v) NaCl (optimum 2-3%) and pH 6.0-9.0 (optimum pH 7.5). The major respiratory quinone detected was ubiquinone 10 (U-10) and the genomic DNA G+C content was 66.7±0.4 mol%. Major fatty acids (>5%) were C(16 : 0), C(18 : 1)ω7c and 11-methyl C(18 : 1)ω7c. The polar lipids consisted of diphosphatidylglycerol, five glycolipids, phosphatidylglycerol and an unknown phospholipid. Phylogenetic analysis showed the closest relatives of strain GU51(T) were members of the genus Parvularcula with 92.3% 16S rRNA gene sequence similarity. On the basis of this polyphasic taxonomic characterization, it is suggested that strain GU51(T) represents a novel species of a new genus in the family 'Parvularculaceae', for which the name Amphiplicatus metriothermophilus gen. nov., sp. nov. is proposed. The type strain of the type species is GU51(T) ( = CGMCC 1.12710(T) = JCM 19779(T)).

Rhodoligotrophos appendicifer gen. nov., sp. nov., an appendaged bacterium isolated from a freshwater Antarctic lake

A Gram-stain-negative, non-spore-forming, non-motile, irregularly circular, aerobic/microaerobic appendaged bacterium (strain 120-1(T)) was isolated from Naga-ike, one of the freshwater lakes in the Skarvsnes ice-free area of Antarctica. Strain 120-1(T) grew between 5 and 35 °C, with optimum growth at 30 °C. The pH range for growth was between 6.0 and 9.0 (optimum of approximately pH 7.0). The range of NaCl concentration allowing growth of strain 120-1(T) was between 0 and 5.0%, with an optimum of 0.5-1.0%. Strain 120-1(T) was able to utilize organic compounds such as glucose, arabinose, gluconate, adipate and malate. Red colonies were formed on plate medium and the carotenoids were present in the cells. Ubiquinones Q-9 and Q-10 were the major respiratory quinones. The major cellular fatty acids were C(16:0), C(18:1)ω9c and C(18:1)ω7c. The G+C content of the genomic DNA was 61.1 mol%. Comparative analyses of 16S rRNA gene sequences and physiological characteristics of strain 120-1(T) indicate that strain 120-1(T) is a phylogenetically novel bacterium, and that it represents a novel species in a new genus, Rhodoligotrophos gen. nov., in the order Rhizobiales, family Rhodobiaceae. The name Rhodoligotrophos appendicifer gen. nov. sp. nov. is proposed as the type species of this new genus, with 120-1(T) ( = JCM 16873(T) = ATCC BAA-2115(T)) as the type strain.

Tepidamorphus gemmatus gen. nov., sp. nov., a slightly thermophilic member of the Alphaproteobacteria

Two isolates, with an optimum growth temperature of about 45-50 degrees C and an optimum pH for growth between 7.5 and 8.5, were recovered from a hot spring in the Furnas area on the Island of São Miguel in the Azores. Strains form irregular rod-shaped cells are motile and stain Gram negative. The cells multiply by budding. These strains are non-pigmented, strictly aerobic, catalase and oxidase positive. These organisms assimilated carbohydrates, organic acids and amino acids. The major fatty acids are 19:0(cyclo omega8c) and 18:0. Ubiquinone 10 is the major respiratory quinone. The major polar lipids are diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine in addition to one unidentified aminolipid and one unidentified glycolipid. Bacteriochlorophyll a, puf genes and RuBisCo genes were not detected. Analysis of the 16SrRNA gene shows the strains to cluster with species of the genera Afifella, Rhodobium, Anderseniella and Amorphus to which they have sequence similarity in the range 93-94%. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain CB-27A(T) (=DSM 19345(T)=LMG 24113(T)) for which we propose the name Tepidamorphus gemmatus.

Amorphus coralli gen. nov., sp. nov., a marine bacterium isolated from coral mucus, belonging to the order Rhizobiales

A bacterial strain, designated RS.Sph.026(T), was isolated from mucus of the coral Fungia granulosa collected from the northern Red Sea (Gulf of Eilat, Israel). The bacterium was found to be Gram-negative, non-motile, halotolerant and heterotrophic. Comparative 16S rRNA gene sequence analyses showed that strain RS.Sph.026(T) belonged to the order Rhizobiales, with the highest levels of 16S RNA gene sequence similarity with Rhodobium orientis (92 %). Strain RS.Sph.026(T) grew optimally at a salinity of 3-4 %, pH 7.5-8 and 25-30 degrees C. The major cellular fatty acids were cis-7-octadecenoic acid (C(18 : 1)omega7small es, Cyrillic; 57.2 %) and C(19 : 0) cyclo omega8small es, Cyrillic (15.5 %). The DNA G+C content of strain RS.Sph.026(T) was 67.1 mol%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain RS.Sph.026(T) represents a novel genus and species in the order Rhizobiales, for which the name Amorphus coralli gen. nov., sp. nov. is proposed. The type strain is RS.Sph.026(T) (=LMG 24307(T)=DSM 19760(T)).