Ectothiorhodospira lacustris sp. nov., a New Purple Sulfur Bacterium from Low-Mineralized Soda Lakes That Contains a Unique Pathway for Nitric Oxide Reduction.

Several strains of a Gram-negative, anaerobic photoautotrophic, motile, rod-shaped bacterium, designated as B14B, A-7R, and A-7Y were isolated from biofilms of low-mineralized soda lakes in central Mongolia and Russia (southeast Siberia). They had lamellar stacks as photosynthetic structures and bacteriochlorophyll a as the major photosynthetic pigment. The strains were found to grow at 25-35 °C, pH 7.5-10.2 (optimum, pH 9.0), and with 0-8% (w/v) NaCl (optimum, 0%). In the presence of sulfide and bicarbonate, acetate, butyrate, yeast extract, lactate, malate, pyruvate, succinate, and fumarate promoted growth. The DNA G + C content was 62.9-63.0 mol%. While the 16S rRNA gene sequences confirmed that the new strains belonged to the genus Ectothiorhodospira of the Ectothiorhodospiraceae, comparison of the genome nucleotide sequences of strains B14B, A-7R, and A-7Y revealed that the new isolates were remote from all described Ectothiorhodospira species both in dDDH (19.7-38.8%) and in ANI (75.0-89.4%). The new strains are also genetically differentiated by the presence of a nitric oxide reduction pathway that is lacking from all other Ectiothiorhodospiraceae. We propose to assign the isolates to the new species, Ectothiorhodospira lacustris sp. nov., with the type strain B14BT (=DSM 116064T = KCTC 25542T = UQM 41491T).

Comparative Genome Analysis of the Photosynthetic Betaproteobacteria of the Genus Rhodocyclus: Heterogeneity within Strains Assigned to Rhodocyclus tenuis and Description of Rhodocyclus gracilis sp. nov. as a New Species.

The genome sequences for Rhodocyclus purpureus DSM 168T and four strains assigned to Rhodocyclus tenuis (DSM 110, DSM 111, DSM 112, and IM 230) have been determined. One of the strains studied (IM 230) has an average nucleotide identity (ANI) of 97% to the recently reported genome of the type strain DSM 109 of Rcy. tenuis and is regarded as virtually identical at the species level. The ANI of 80% for three other strains (DSM 110, DSM 111, DSM 112) to the type strain of Rcy. tenuis points to a differentiation of these at the species level. Rcy. purpureus is equidistant from Rcy. tenuis and the new species, based on both ANI (78-80%) and complete proteome comparisons (70% AAI). Strains DSM 110, DSM 111, and DSM 112 are very closely related to each other based on ANI, whole genome, and proteome comparisons but clearly distinct from the Rcy. tenuis type strain DSM 109. In addition to the whole genome differentiation, these three strains also contain unique genetic differences in cytochrome genes and contain genes for an anaerobic cobalamin synthesis pathway that is lacking from both Rcy. tenuis and Rcy. purpureus. Based on genomic and genetic differences, these three strains should be considered to represent a new species, which is distinctly different from both Rcy. purpureus and Rcy. tenuis, for which the new name Rhodocyclus gracilis sp. nov. is proposed.

Genomic Comparison, Phylogeny and Taxonomic Reevaluation of the Ectothiorhodospiraceae and Description of Halorhodospiraceae fam. nov. and Halochlorospira gen. nov.

The Ectothiorhodospiraceae family represents purple sulfur bacteria of the Gammaproteobacteria found primarily in alkaline soda lakes of moderate to extremely high salinity. The main microscopically visible characteristic separating them from the Chromatiaceae is the excretion of the intermediate elemental sulfur formed during oxidation of sulfide prior to complete oxidation to sulfate rather than storing it in the periplasm. We present a comparative study of 38 genomes of all species of phototrophic Ectothiorhodospiraceae. We also include a comparison with those chemotrophic bacteria that have been assigned to the family previously and critically reevaluate this assignment. The data demonstrate the separation of Halorhodospira species in a major phylogenetic branch distant from other Ectothiorhodospiraceae and support their separation into a new family, for which the name Halorhodospiraceae fam. nov. is proposed. In addition, the green-colored, bacteriochlorophyll-containing species Halorhodospira halochloris and Halorhodospira abdelmalekii were transferred to the new genus Halochlorospira gen. nov. of this family. The data also enable classification of several so far unclassified isolates and support the separation of Ectothiorhodospira shaposhnikovii and Ect. vacuolata as well as Ect. mobilis and Ect. marismortui as distinct species.

Micromonospora tarapacensis sp. nov., a bacterium isolated from a hypersaline lake.

Strain Llam7T was isolated from microbial mat samples from the hypersaline lake Salar de Llamará, located in Taracapá region in the hyper-arid core of the Atacama Desert (Chile). Phenotypic, chemotaxonomic and genomic traits were studied. Phylogenetic analyses based on 16S rRNA gene sequences assigned the strain to the family Micromonosporaceae with affiliation to the genera Micromonospora and Salinispora. Major fatty acids were C17 : 1ω8c, iso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. The cell walls contained meso-diaminopimelic acid and ll-2,6 diaminopimelic acid (ll-DAP), while major whole-cell sugars were glucose, mannose, xylose and ribose. The major menaquinones were MK-9(H4) and MK-9(H6). As polar lipids phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and several unidentified lipids, i.e. two glycolipids, one aminolipid, three phospholipids, one aminoglycolipid and one phosphoglycolipid, were detected. Genome sequencing revealed a genome size of 6.894 Mb and a DNA G+C content of 71.4 mol%. Phylogenetic analyses with complete genome sequences positioned strain Llam7T within the family Micromonosporaceae forming a distinct cluster with Micromonospora (former Xiangella) phaseoli DSM 45730T. This cluster is related to Micromonospora pelagivivens KJ-029T, Micromonospora craterilacus NA12T, and Micromonospora craniellae LHW63014T as well as to all members of the former genera Verrucosispora and Jishengella, which were re-classified as members of the genus Micromonospora, forming a clade distinct from the genus Salinispora. Pairwise whole genome average nucleotide identity (ANI) values, digital DNA-DNA hybridization (dDDH) values, the presence of the diamino acid ll-DAP, and the composition of whole sugars and polar lipids indicate that Llam7T represents a novel species, for which the name Micromonospora tarapacensis sp. nov. is proposed, with Llam7T (=DSM 109510T,=LMG 31023T) as the type strain.

Editorial for the Special Issue: Advances in the Biology of Phototrophic Bacteria.

Phototrophic bacteria represent a very ancient phylogenetic and highly diverse metabolic type of bacteria that diverged early into several major phylogenetic lineages with quite different properties [...].

Phylogenetic relationship of phototrophic heliobacteria and systematic reconsideration of species and genus assignments based on genome sequences of eight species.

The draft genome sequences of five species of named phototrophic heliobacteria in the order Clostridiales were determined. Whole genome phylogenetic and average nucleotide identity comparison for the heliobacteria suggests that Heliobacterium chlorum and Heliobacillus mobilis are closely related to one another and belong to the same genus. The three species Heliobacterium modesticaldum, Heliobacterium undosum and Heliobacterium gestii all belong in the same genus, but are more divergent from Hbt. chlorum and belong in a separate genus, which we suggest to be called Heliomicrobium. Heliorestis convoluta is properly recognized to be in the same genus as Heliorestis acidaminivorans. Heliophilum fasciatum is clearly unlike any other and rightfully belongs in a separate genus.

Glaciibacter flavus sp. nov., isolated from a lichen sample.

A novel Actinobacterium strain YIM 131861 T, was isolated from lichen collected from the South Bank Forest of the Baltic Sea, Germany. It was Gram-stain-positive, strictly aerobic, catalase positive and oxidase negative, yellow pigmented. Cells were motile with a polar flagellum, irregular rod shaped and did not display spore formation. The strain grew at 15 - 30 °C (optimum 25 °C), at pH 6.0 - 10.0 (optimum pH 7.0) and in the presence of 0 - 1.5% (w/v) NaCl (optimum 1%). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM 131861 T belonged to the genus Glaciibacter, and exhibited a high sequence similarity (96.4%) with Glaciibacter superstes NBRC 104264 T. The genomic DNA G + C content of strain YIM 131861 T was 68.2 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain YIM 131861 T and Glaciibacter superstes NBRC 104264 T were 73.2 and 19.9% based on the draft genome sequence. The cell-wall peptidoglycan type was B2γ and contained the 2, 4-diaminobutyric acid as the diagnostic amino acid. Whole cell sugars were galactose, rhamnose, ribose and glucose. It contained MK-12 and MK-13 as the predominant menaquinones. The major cellular fatty acids (> 10%) were identified as anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two unknown glycolipids. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain YIM 131861 T should belong to the genus Glaciibacter and represents a novel species of the genus Glaciibacter, for which the name Glaciibacter flavus sp. nov. is proposed. The type strain is YIM 131861 T (= CGMCC 1.16588 T = NBRC 113572 T).

The genome sequence of the giant phototrophic gammaproteobacterium Thiospirillum jenense gives insight into its physiological properties and phylogenetic relationships.

In a conserved culture of the purple sulfur bacterium Thiospirillum jenense DSM216T, cells of this species were easily recognized by cell morphology, large-size spirilla and visible flagellar tuft. The Tsp. jenense genome is 3.22 Mb in size and has a GC content of 48.7 mol%. It was readily identified as a member of the Chromatiaceae by the complement of proteins in its genome. A whole genome comparison clearly placed Tsp. jenense near Thiorhodovibrio and Rhabdochromatium species and somewhat more distant from Thiohalocapsa and Halochromatium species. This relationship was also found with the sequences of the photosynthetic reaction center protein PufM. The genome sequence supported important properties of this bacterium: the presence of ribulose-bisphosphate carboxylase and enzymes of the Calvin cycle of autotrophic carbon dioxide fixation but the absence of carboxysomes, an incomplete tricarboxylic acid cycle and the lack of malate dehydrogenase, the presence of a sulfur oxidation pathway including adenylylsulfate reductase (aprAB) but absence of assimilatory sulfate reduction, the presence of hydrogenase (hoxHMFYUFE), nitrogenase and a photosynthetic gene cluster (pufBALMC). The FixNOP type of cytochrome oxidase was notably lacking, which may be the reason that renders the cells highly sensitive to oxygen. Two minor phototrophic contaminants were found using metagenomic binning: one was identified as a strain of Rhodopseudomonas palustris and the second one has an average nucleotide identity of 82% to the nearest neighbor Rhodoferax antarcticus. It should be considered as a new species of this genus and Rhodoferax jenense is proposed as the name.

Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses.

Osmotic adaptation and accumulation of compatible solutes is a key process for life at high osmotic pressure and elevated salt concentrations. Most important solutes that can protect cell structures and metabolic processes at high salt concentrations are glycine betaine and ectoine. The genome analysis of more than 130 phototrophic bacteria shows that biosynthesis of glycine betaine is common among marine and halophilic phototrophic Proteobacteria and their chemotrophic relatives, as well as in representatives of Pirellulaceae and Actinobacteria, but are also found in halophilic Cyanobacteria and Chloroherpeton thalassium. This ability correlates well with the successful toleration of extreme salt concentrations. Freshwater bacteria in general lack the possibilities to synthesize and often also to take up these compounds. The biosynthesis of ectoine is found in the phylogenetic lines of phototrophic Alpha- and Gammaproteobacteria, most prominent in the Halorhodospira species and a number of Rhodobacteraceae. It is also common among Streptomycetes and Bacilli. The phylogeny of glycine-sarcosine methyltransferase (GMT) and diaminobutyrate-pyruvate aminotransferase (EctB) sequences correlate well with otherwise established phylogenetic groups. Most significantly, GMT sequences of cyanobacteria form two major phylogenetic branches and the branch of Halorhodospira species is distinct from all other Ectothiorhodospiraceae. A variety of transport systems for osmolytes are present in the studied bacteria.

Genomic and genetic sequence information of strains assigned to the genus Rhodopseudomonas reveal the great heterogeneity of the group and identify strain Rhodopseudomonas palustris DSM 123T as the authentic type strain of this species.

The genus Rhodopseudomonas, containing purple nonsulfur photosynthetic Proteobacteria, has a number of strains that belong to different species, although many of them are collectively called Rhodopseudomonas palustris. The type species R. palustris and closely related species are the focus of this paper. The comparison of available genome sequences indicate that the following Rhodopseudomonas species are well recognized: R. palustris (strains ATH 2.1.6T=DSM 123T=NBRC 100419T and BisB5), Rhodopseudomonas rutila (strains R1T, DSM 126, CGA009, ATH 2.1.37, Eli 1980, ATCC 17001 and TIE1), Rhodopseudomonas pentothenatexigens JA575T and Rhodopseudomonas faecalis JCM 11668T. Other strains for which genome sequences are available are distinct from these four species. Evidence is presented that R. palustris strain ATH 2.1.6T-KCM as obtained directly from the van Niel collection by one of us (T.E.M.) is identical to the DSMZ deposit DSM 123T of ATH 2.1.6T, but not to the deposit at ATCC 17001. The amino acid sequences of the cytochromes C2 and C556 from R. palustris strain ATH 2.1.6T-KCM are in complete agreement with the translated genome sequences of R. palustris DSM 123T. In addition, the 16S rRNA gene sequence of R. palustris NBRC 100419T completely matches that of strain DSM 123T. In conclusion, the type strain of R. palustris ATH 2.1.6T is correctly represented by DSM 123T and NBRC 100419T. However, the deposit at ATCC 17001 has properties that do not conform with properties of authentic R. palustris, but rather indicate that this is a strain of R. rutila. The previously suggested assignment of the type strain of R. palustris DSM 123T to the new species R. pseudopalustris was incorrect because strain DSM 123T is the authentic type strain of R. palustris.

Genome analysis of the marine bacterium Kiloniella laminariae and first insights into comparative genomics with related Kiloniella species.

Kiloniella laminariae is a true marine bacterium and the first member of the family and order, the Kiloniellaceae and Kiloniellales. K. laminariae LD81T (= DSM 19542T) was isolated from the marine macroalga Saccharina latissima and is a mesophilic, typical marine chemoheterotrophic aerobic bacterium with antifungal activity. Phylogenetic analysis of 16S rRNA gene sequence revealed the similarity of K. laminariae LD81T not only with three validly described species of the genus Kiloniella, but also with undescribed isolates and clone sequences from marine samples in the range of 93.6-96.7%. We report on the analysis of the draft genome of this alphaproteobacterium and describe some selected features. The 4.4 Mb genome has a G + C content of 51.4%, contains 4213 coding sequences including 51 RNA genes as well as 4162 protein-coding genes, and is a part of the Genomic Encyclopaedia of Bacteria and Archaea (GEBA) project. The genome provides insights into a number of metabolic properties, such as carbon and sulfur metabolism, and indicates the potential for denitrification and the biosynthesis of secondary metabolites. Comparative genome analysis was performed with K. laminariae LD81T and the animal-associated species Kiloniella majae M56.1T from a spider crab, Kiloniella spongiae MEBiC09566T from a sponge as well as Kiloniella litopenai P1-1 from a white shrimp, which all inhabit quite different marine habitats. The analysis revealed that the K. laminariae LD81T contains 1397 unique genes, more than twice the amount of the other species. Unique among others is a mixed PKS/NRPS biosynthetic gene cluster with similarity to the biosynthetic gene cluster responsible for the production of syringomycin.

Phylogeny of Anoxygenic Photosynthesis Based on Sequences of Photosynthetic Reaction Center Proteins and a Key Enzyme in Bacteriochlorophyll Biosynthesis, the Chlorophyllide Reductase.

Photosynthesis is a key process for the establishment and maintenance of life on earth, and it is manifested in several major lineages of the prokaryote tree of life. The evolution of photosynthesis in anoxygenic photosynthetic bacteria is of major interest as these have the most ancient roots of photosynthetic systems. The phylogenetic relations between anoxygenic phototrophic bacteria were compared on the basis of sequences of key proteins of the type-II photosynthetic reaction center, including PufLM and PufH (PuhA), and a key enzyme of bacteriochlorophyll biosynthesis, the light-independent chlorophyllide reductase BchXYZ. The latter was common to all anoxygenic phototrophic bacteria, including those with a type-I and those with a type-II photosynthetic reaction center. The phylogenetic considerations included cultured phototrophic bacteria from several phyla, including Proteobacteria (138 species), Chloroflexi (five species), Chlorobi (six species), as well as Heliobacterium modesticaldum (Firmicutes), Chloracidobacterium acidophilum (Acidobacteria), and Gemmatimonas phototrophica (Gemmatimonadetes). Whenever available, type strains were studied. Phylogenetic relationships based on a photosynthesis tree (PS tree, including sequences of PufHLM-BchXYZ) were compared with those of 16S rRNA gene sequences (RNS tree). Despite some significant differences, large parts were congruent between the 16S rRNA phylogeny and photosynthesis proteins. The phylogenetic relations demonstrated that bacteriochlorophyll biosynthesis had evolved in ancestors of phototrophic green bacteria much earlier as compared to phototrophic purple bacteria and that multiple events independently formed different lineages of aerobic phototrophic purple bacteria, many of which have very ancient roots. The Rhodobacterales clearly represented the youngest group, which was separated from other Proteobacteria by a large evolutionary gap.

High diversity and novelty of Actinobacteria isolated from the coastal zone of the geographically remote young volcanic Easter Island, Chile

Easter Island is an isolated volcanic island in the Pacific Ocean. Despite the extended knowledge about its origin, flora, and fauna, little is known about the bacterial diversity inhabiting this territory. Due to its isolation, Easter Island can be considered as a suitable place to evaluate microbial diversity in a geographically isolated context, what could shed light on actinobacterial occurrence, distribution, and potential novelty. In the present study, we performed a comprehensive analysis of marine Actinobacteria diversity of Easter Island by studying a large number of coastal sampling sites, which were inoculated into a broad spectrum of different culture media, where most important variations in composition included carbon and nitrogen substrates, in addition to salinity. The isolates were characterized on the basis of 16S ribosomal RNA gene sequencing and phylogenetic analysis. High actinobacterial diversity was recovered with a total of 163 pure cultures of Actinobacteria representing 72 phylotypes and 20 genera, which were unevenly distributed in different locations of the island and sample sources. The phylogenetic evaluation indicated a high degree of novelty showing that 45% of the isolates might represent new taxa. The most abundant genera in the different samples were Micromonospora, Streptomyces, Salinispora, and Dietzia. Two aspects appear of primary importance in regard to the high degree of novelty and diversity of Actinobacteria found. First, the application of various culture media significantly increased the number of species and genera obtained. Second, the geographical isolation is considered to be of importance regarding the actinobacterial novelty found

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Different Secondary Metabolite Profiles of Phylogenetically almost Identical Streptomyces griseus Strains Originating from Geographically Remote Locations.

As Streptomyces have shown an outstanding capacity for drug production, different campaigns in geographically distant locations currently aim to isolate new antibiotic producers. However, many of these newly isolated Streptomyces strains are classified as identical to already described species. Nevertheless, as discrepancies in terms of secondary metabolites and morphology are possible, we compared two Streptomyces strains with identical 16S rRNA gene sequences but geographically distant origins. Chosen were an Easter Island Streptomyces isolate (Streptomyces sp. SN25_8.1) and the next related type strain, which is Streptomyces griseus subsp. griseus DSM 40236T isolated from Russian garden soil. Compared traits included phylogenetic relatedness based on 16S rRNA gene sequences, macro and microscopic morphology, antibiotic activity and secondary metabolite profiles. Both Streptomyces strains shared several common features, such as morphology and core secondary metabolite production. They revealed differences in pigmentation and in the production of accessory secondary metabolites which appear to be strain-specific. In conclusion, despite identical 16S rRNA classification Streptomyces strains can present different secondary metabolite profiles and may well be valuable for consideration in processes for drug discovery.

Structures and biological activities of cycloheptamycins A and B.

The heptadepsipeptide cycloheptamycin A was isolated from the terrestrial Streptomyces sp. Tü 6314. Its constitution was elucidated on the basis of NMR spectroscopic experiments and mass spectrometric analysis. Its stereostructure was investigated by peptide hydrolysis and derivatization and firmly established by X-ray structure analysis. In addition to the parent compound, a new cycloheptamycin analog, cycloheptamycin B, was discovered and structurally assigned using comparative MS/MS experiments and NMR. The biological profile of both compounds was investigated, revealing a selective inhibitory potential of cycloheptamycins against Propionibacterium acnes.

Systematic Affiliation and Genome Analysis of Subtercola vilae DB165T with Particular Emphasis on Cold Adaptation of an Isolate from a High-Altitude Cold Volcano Lake.

Among the Microbacteriaceae the species of Subtercola and Agreia form closely associated clusters. Phylogenetic analysis demonstrated three major phylogenetic branches of these species. One of these branches contains the two psychrophilic species Subtercola frigoramans and Subtercola vilae, together with a larger number of isolates from various cold environments. Genomic evidence supports the separation of Agreia and Subtercola species. In order to gain insight into the ability of S. vilae to adapt to life in this extreme environment, we analyzed the genome with a particular focus on properties related to possible adaptation to a cold environment. General properties of the genome are presented, including carbon and energy metabolism, as well as secondary metabolite production. The repertoire of genes in the genome of S. vilae DB165T linked to adaptations to the harsh conditions found in Llullaillaco Volcano Lake includes several mechanisms to transcribe proteins under low temperatures, such as a high number of tRNAs and cold shock proteins. In addition, S. vilae DB165T is capable of producing a number of proteins to cope with oxidative stress, which is of particular relevance at low temperature environments, in which reactive oxygen species are more abundant. Most important, it obtains capacities to produce cryo-protectants, and to combat against ice crystal formation, it produces ice-binding proteins. Two new ice-binding proteins were identified which are unique to S. vilae DB165T. These results indicate that S. vilae has the capacity to employ different mechanisms to live under the extreme and cold conditions prevalent in Llullaillaco Volcano Lake.

Antitumor Anthraquinones from an Easter Island Sea Anemone: Animal or Bacterial Origin?

The presence of two known anthraquinones, Lupinacidin A and Galvaquinone B, which have antitumor activity, has been identified in the sea anemone (Gyractis sesere) from Easter Island. So far, these anthraquinones have been characterized from terrestrial and marine Actinobacteria only. In order to identify the anthraquinones producer, we isolated Actinobacteria associated with the sea anemone and obtained representatives of seven actinobacterial genera. Studies of cultures of these bacteria by HPLC, NMR, and HRLCMS analyses showed that the producer of Lupinacidin A and Galvaquinone B indeed was one of the isolated Actinobacteria. The producer strain, SN26_14.1, was identified as a representative of the genus Verrucosispora. Genome analysis supported the biosynthetic potential to the production of these compounds by this strain. This study adds Verrucosispora as a new genus to the anthraquinone producers, in addition to well-known species of Streptomyces and Micromonospora. By a cultivation-based approach, the responsibility of symbionts of a marine invertebrate for the production of complex natural products found within the animal's extracts could be demonstrated. This finding re-opens the debate about the producers of secondary metabolites in sea animals. Finally, it provides valuable information about the chemistry of bacteria harbored in the geographically-isolated and almost unstudied, Easter Island.

Emended description of the genus Tabrizicola and the species Tabrizicola aquatica as aerobic anoxygenic phototrophic bacteria.

The genus Tabrizicola with its type species and strain Tabrizicola aquatica RCRI19T was previously described as a purely chemotrophic genus of Gram-negative, aerobic, non-motile and rod-shaped bacteria. With the present study, we expand the description of the metabolic capabilities of this genus and the T. aquatica type strain to include chlorophyll-dependent phototrophy. Our results confirmed that T. aquatica, does not grow under anaerobic photoautotrophic or photoheterotrophic conditions. However, the presence of the photosynthesis-related genes pufL and pufM could be demonstrated in the genomes of several Tabrizicola strains. Additionally, photosynthetic pigments (bacteriochlorophyll a) were formed under aerobic, heterotrophic and low light conditions in T. aquatica strain RCRI19T. Furthermore, all the genes necessary for a fully operational photosynthetic apparatus and bacteriochlorophyll a are present in the T. aquatica type strain genome. Therefore, we suggest categorising T. aquatica RCRI19T, isolated from freshwater environment of Qurugöl Lake, as an aerobic anoxygenic phototrophic (AAP) bacterium.