Corynebacterium antarcticum sp. nov., Corynebacterium marambiense sp. nov., Corynebacterium meridianum sp. nov., and Corynebacterium pygosceleis sp. nov., isolated from Adélie penguins (Pygoscelis adeliae)

A taxonomic study was conducted on 16 bacterial strains isolated from wild Adélie penguins (Pygoscelis adeliae) from Seymour (Marambio) Island and James Ross Island. An initial screening by repetitive sequence-based PCR fingerprinting divided the strains studied into four coherent groups. Phylogenetic analysis based on 16S rRNA gene sequences assigned all groups to the genus Corynebacterium and showed that Corynebacterium glyciniphilum and Corynebacterium terpenotabidum were the closest species with 16S rRNA gene sequence similarities between 95.4 % and 96.5 %. Further examination of the strains studied with ribotyping, MALDI-TOF mass spectrometry, comprehensive biotyping and calculation of average nucleotide identity and digital DNA–DNA hybridisation values confirmed the separation of the four groups from each other and from the other Corynebacterium species. Chemotaxonomically, the four strains P5828^T, P5850^T, P6136^T, P7210^T representing the studied groups were characterised by C_16:0 and C_18:1 ω9c as the major fatty acids, by the presence of meso-diaminopimelic acid in the peptidoglycan, the presence of corynemycolic acids and a quinone system with the predominant menaquinone MK-9(H₂). The results of this study show that the strains studied represent four new species of the genus Corynebacterium, for which the names Corynebacterium antarcticum sp. nov. (type strain P5850^T = CCM 8835^T = LMG 30620^T), Corynebacterium marambiense sp. nov. (type strain P5828^T = CCM 8864^T = LMG 31626^T), Corynebacterium meridianum sp. nov. (type strain P6136^T = CCM 8863^T = LMG 31628^T) and Corynebacterium pygosceleis sp. nov. (type strain P7210^T = CCM 8836^T = LMG 30621^T) are proposed.     

Anditalea andensis gen. nov., sp. nov., an alkaliphilic, halotolerant bacterium isolated from extreme alkali–saline soil

A novel alkalophilic salt-tolerant rod-shaped bacterium, designated ANESC-S^T, was isolated from an extremely alkali–saline soil in the rural area of Anda city in northeast China. Taxonomic study using a polyphasic approach revealed that this non-motile, orange colony-forming microbe was Gram-negative and obligately aerobic. Optimal growth of strain ANESC-S^T was achieved in the presence of NaCl with a concentration range of 0.5 to 4 % and pH between 7.5 and 9.2, and at temperatures ranging from 10 to 37 °C. Phylogenetic analysis of 16S rRNA sequences showed that of strain ANESC-S^T is most homologous to Mongoliicoccus roseus MIM28^T and Litoribacter ruber YIM CH208^T with sequence similarity of 95.1 and 93.2 %, respectively. The genomic DNA G+C content of strain ANESC-S^T was determined to be 39.1 mol%. The main isoprenoid quinone in ANESC-S^T was found to be menaquinone-7. The main fatty acids were found to be iso-C_15:0 (27.5 %), iso-C_17:03-OH (14.0 %), anteiso-C_15:0 (9.8 %), summed feature 9 (iso-C_17:1ω9c and/or 10-methyl C_16:0 10.6 %) and summed feature 3 (C_16:1w7c/C_16:1w6c, 9.78 %). Based on the phenotypic, chemotaxonomic and phylogenetic data, strain ANESC-S^T is considered to represent a new genus and species classified into the order Cytophagales, for which the name Anditalea andensis gen. nov., sp. nov. is proposed. The type strain is ANESC-S^T (=CICC 10485^T = NCCB 100412^T).     

Ameyamaea chiangmaiensis gen. nov., sp. nov., an Acetic Acid Bacterium in the α-Proteobacteria

Two isolates, AC04^T and AC05, were isolated from the flowers of red ginger collected in Chiang Mai, Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates were included within a lineage comprised of the genera Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Neoasaia, Granulibacter, and Tanticharoenia, and they formed an independent cluster along with the type strain of Tanticharoenia sakaeratensis. The calculated pair-wise sequence similarities of isolate AC04^T were 97.8–92.5% to the type strains of the type species of the 11 genera of acetic acid bacteria. The DNA base composition was 66.0–66.1 mol % G+C with a range of 0.1 mol %. A single-stranded, labeled DNA from isolate AC04^T presented levels of DNA-DNA hybridization of 100, 85, 4, and 3% respectively to DNAs from isolates AC04^T and AC05 and the type strains of Tanticharoenia sakaeratensis and Gluconacetobacter liquefaciens. The two isolates were unique morphologically in polar flagellation and physiologically in intense acetate oxidation to carbon dioxide and water and weak lactate oxidation. The intensity in acetate oxidation almost equaled that of the type strain of Acetobacter aceti. The two isolates had Q-10. Isolate AC04^T was discriminated from the type strains of the type species of the 11 genera by 16S rRNA gene restriction analysis using restriction endonucleases TaqI and Hin6I. The unique phylogenetic, genetic, morphological, physiological, and biochemical characteristics obtained indicate that the two isolates can be classified into a separate genus, and Ameyamaea chiangmaiensis gen. nov., sp. nov. is proposed. The type strain is isolate AC04^T (=BCC 15744^T, =NBRC 103196^T), which has a DNA G+C content of 66.0 mol %.     

Neokomagataea gen. nov., with Descriptions of Neokomagataea thailandica sp. nov. and Neokomagataea tanensis sp. nov., Osmotolerant Acetic Acid Bacteria of the α-Proteobacteria

Isolates AH11^T and AH13^T were isolated from flowers of lantana and candle bush respectively collected in Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates formed an independent cluster, which was then connected to the type strain of Saccharibacter floricola. The calculated pair-wise 16S rRNA gene sequence similarities of isolate AH11^T were 95.7–92.3% to the type strains of the type species of the 12 genera of acetic acid bacteria. The DNA base composition was from 51.2 to 56.8 mol % G+C, with a range of 5.6 mol %. When isolate AH11^T was labeled, DNA-DNA similarities were 100, 12, 4, 5, and 4% respectively to isolates AH11^T and AH13^T and the type strains of Saccharibacter floricola, Gluconobacter oxydans, and Acetobacter aceti. The two isolates were non-motile and did not oxidize either acetate or lactate. No growth was found in the presence of 0.35% acetic acid w/v. The two isolates were not osmophilic but osmotolerant, produced 2,5-diketo-D-gluconate from D-glucose, and did not oxidize lactate, thus differing from strains of Saccharibacter floricola, which showed weak lactate oxidation. The two isolates contained unsaturated C_18:1ω7c fatty acid as the major fatty acid, and were unique in the presence of a considerable amount of straight-chain C_18:12OH fatty acid. Q-10 was present as the major isoprenoid quinone. Neokomagataea gen. nov. was proposed with the two species, Neokomagataea thailandica sp. nov. for isolate AH11^T (=BCC 25710 ^T =NBRC 106555^T), which has 56.8 mol % G+C, and Neokomagataea tanensis sp. nov. for isolate AH13^T (=BCC 25711^T=NBRC 106556^T), which has 51.2 mol % G+C.     

Neokomagataea gen. nov., with descriptions of Neokomagataea thailandica sp. nov. and Neokomagataea tanensis sp. nov., osmotolerant acetic acid bacteria of the α-Proteobacteria

Isolates AH11(T) and AH13(T) were isolated from flowers of lantana and candle bush respectively collected in Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates formed an independent cluster, which was then connected to the type strain of Saccharibacter floricola. The calculated pair-wise 16S rRNA gene sequence similarities of isolate AH11(T) were 95.7-92.3% to the type strains of the type species of the 12 genera of acetic acid bacteria. The DNA base composition was from 51.2 to 56.8 mol % G+C, with a range of 5.6 mol %. When isolate AH11(T) was labeled, DNA-DNA similarities were 100, 12, 4, 5, and 4% respectively to isolates AH11(T) and AH13(T) and the type strains of Saccharibacter floricola, Gluconobacter oxydans, and Acetobacter aceti. The two isolates were non-motile and did not oxidize either acetate or lactate. No growth was found in the presence of 0.35% acetic acid w/v. The two isolates were not osmophilic but osmotolerant, produced 2,5-diketo-D-gluconate from D-glucose, and did not oxidize lactate, thus differing from strains of Saccharibacter floricola, which showed weak lactate oxidation. The two isolates contained unsaturated C(18:1)ω7c fatty acid as the major fatty acid, and were unique in the presence of a considerable amount of straight-chain C(18:1)2OH fatty acid. Q-10 was present as the major isoprenoid quinone. Neokomagataea gen. nov. was proposed with the two species, Neokomagataea thailandica sp. nov. for isolate AH11(T) (=BCC 25710(T)=NBRC 106555(T)), which has 56.8 mol % G+C, and Neokomagataea tanensis sp. nov. for isolate AH13(T) (=BCC 25711(T)=NBRC 106556(T)), which has 51.2 mol % G+C.     

Oramoeba fumarolia gen. nov., sp. nov., a new marine heterolobosean amoeboflagellate growing at 54 °C

An amoeba strain was isolated from marine sediment taken from the beach near a fumarole in Italy. The trophozoites of this new marine species transforms into flagellates with variable numbers of flagella, from 2 to 10. The strain forms round to oval cysts. This thermophilic amoeboflagellate grows at temperatures up to 54 °C. Molecular phylogenetic analysis of the small subunit ribosomal DNA (SSU rDNA) places the amoeboflagellate in the Heterolobosea. The closest relatives are Stachyamoeba sp. ATCC50324, a strain isolated from an ocean sample, and Vrihiamoeba italica, a recent isolate from a rice field. Like some other heterolobosean species, this new isolate has a group I intron in the SSU rDNA. Because of the unique place in the molecular phylogenetic tree, and because there is no species found in the literature with similar morphological and physiological characteristics, this isolate is considered to be a new genus and a new species, Oramoeba fumarolia gen. nov., sp. nov.     

‘Candidatus Dichloromethanomonas elyunquensis’ gen. nov., sp. nov., a dichloromethane-degrading anaerobe of the Peptococcaceae family

Taxonomic assignments of anaerobic dichloromethane (DCM)-degrading bacteria remain poorly constrained but are important for understanding the microbial diversity of organisms contributing to DCM turnover in environmental systems. We describe the taxonomic classification of a novel DCM degrader in consortium RM obtained from pristine Rio Mameyes sediment. Phylogenetic analysis of full-length 16S rRNA gene sequences demonstrated that the DCM degrader was most closely related to members of the genera Dehalobacter and Syntrophobotulus, but sequence similarities did not exceed 94% and 93%, respectively. Genome-aggregate average amino acid identities against Peptococcaceae members did not exceed 66%, suggesting that the DCM degrader does not affiliate with any described genus. Phylogenetic analysis of conserved single-copy functional genes supported that the DCM degrader represents a novel clade. Growth strictly depended on the presence of DCM, which was consumed at a rate of 160 ± 3 μmol L^?1 d^?1. The DCM degrader attained 5.25 × 10⁷ ± 1.0 × 10⁷ cells per μmol DCM consumed. Fluorescence in situ hybridization revealed rod-shaped cells 4 ± 0.8 μm long and 0.4 ± 0.1 μm wide. Based on the unique phylogenetic, genomic, and physiological characteristics, we propose that the DCM degrader represents a new genus and species, ‘Candidatus Dichloromethanomonas elyunquensis’.     

Ougandatherium napakense nov. gen. nov. sp., le plus ancien Rhinocerotidae Iranotheriinae d’Afrique

Ougandatherium napakense nov. gen. nov. sp., the earliest Rhinocerotidae Iranotheriinae from Africa. The Uganda Palaeontology Expedition discovered an exceptionally rich fossiliferous channel deposit at Napak I, Karamoja, in 1999, which yielded two partial skeletons of a new genus and species of early Miocene Rhinocerotidae, together with various other mammals and gastropods typical of Faunal Set I of East Africa. The age of the deposits on the basis of both faunal correlation (biochronology) and radio-isotopic dating is ca 19–20 Ma. The new genus and species is a hornless rhinoceros about the size of a small horse, with long slender limb bones and metapodials and hypsodont upper cheek teeth whose enamel is undulate, and fossettes cement-filled. Upper premolars possess an inner wall; this is clearly an iranotheriine morphology. As such it is the earliest known African member of this subfamily, close to the oldest member of the subfamily recently discovered at Bugti in Pakistan, a site whose age is about the same.     

Rhenanoperca minuta nov. gen., nov. sp., ein neuer Percoide (Pisces,Perciformes) aus der Messel-Formation (Mittel-Eozän,Unteres Geiseltalium)

A new genus and species of percoid fishes (Pisces, Perciformes) from the Middle-Eocene Messel-Formation is introduced and delimitated from other palaeogene percoids. A preliminary diagnosis is proposed. As the relationships of this new taxon still remain somewhat imprecise, it is provisionally classified as “Percoidei incertae familiae”.     

Tabrizicola aquatica gen. nov. sp. nov., a novel alphaproteobacterium isolated from Qurugöl Lake nearby Tabriz city, Iran

A novel Gram-negative, aerobic, non-motile and rod-shaped bacterium was isolated from Qurugöl Lake near Tabriz city. The bacterium grew chemoorganolheterotrophically and chemolithoautotrophically. However, photo-organoheterotrophic, photo-lithoautotrophic and fermentative growth could not be demonstrated. The presence of photosynthesis genes pufL and pufM was not shown and photosynthesis pigments were not formed. Strain RCRI19^T grew without NaCl and tolerated up to 3 % NaCl. Growth occurred at pH 6–9 (optimum, pH 7) and 15–55 °C (optimum 40–45 °C). Vitamins were not required for growth. The major fatty acids are C_18:1 ω7C, 11-methyl C_18:1 ω7C, C_18:0 3-OH. The predominant respiratory quinone is ubiquinone Q-10. The G+C content of genomic DNA is 65.9 mol%. Analysis of 16S rRNA sequences showed that strain RCRI19^T has the highest similarities with uncultured environmental sequences followed by members of the genera Rhodobacter (≤95.75 %), Haematobacter (≤95.53 %), Gemmobacter (≤95.17 %) and Falsirhodobacter (94.60 %) in the family Rhodobacteraceae. DNA–DNA relatedness between strain RCRI19^T and the closest phylogenetically related strain, Rhodobacter blasticus LMG 4305^T, was 20 %. Based on its phenotypic and chemotaxonomic characteristics and considering that it does not form photosynthetic pigments and is unable to grow phototrophically, it is concluded that strain RCRI19^T cannot be included into the genus Rhodobacter and any of the other related genera. Therefore, we propose to place the new bacterium into a new genus and species for which the name Tabrizicola aquatica gen. nov. and sp. nov. is proposed. The type strain is RCRI19^T (=BCCM/LMG 25773^T = JCM 17277^T = KCTC 23724^T).     

Roseinatronobacter thiooxidans gen. nov., sp. nov., a new alkaliphilic aerobic bacteriochlorophylla—containing bacterium isolated from a soda lake

Several samples of microbial mat obtained from soda lakes of the Kunkurskaya steppe (Chita region) abundantly populated by purple bacteria were screened for the presence of heterotrophic alkaliphiles capable of oxidizing sulfur compounds to sulfate. This capacity was found in only one pigmented strain, ALG 1, isolated on medium with acetate and thiosulfate at pH 10. The strain was found to be a strictly aerobic and obligately heterotrophic alkaliphile. Growth on medium with acetate was possible within a narrow pH range from 8.5 to 10.4. The strain formed a reddish orange carotenoid and bacteriochlorophylla. Pigments were synthesized only at high concentrations of nitrogen-containing organic compounds (peptone or yeast extract). The production of bacteriochlorophylla was maximal under microaerobic conditions in darkness. Strain ALG 1 could oxidize sulfide, thiosulfate, sulfite, and elemental sulfur to sulfate. In heterotrophically growing culture (pH 10), thiosulfate was not oxidized until the late logarithmic phase. The sulfur-oxidizing activity was maximal at the most alkaline pH values. The notable increase in the efficiency of organic carbon utilization observed in the presence of thiosulfate suggested that the bacterium was a sulfur-oxidizing lithoheterotroph. The phylogenetic analysis of the 16S rRNA gene showed strain ALG 1 to be a member of the α-3 subgroup of Proteobacteria and to constitute a distinct branch located between nonsulfur purple bacteriaRhodobacter andRhodovulum. Based on the unique phenotypic properties and the results of phylogenetic analysis, the alkaliphilic isolate ALG 1 was assigned to a new genus and speciesRoseinatronobacter thiooxidans with the type strain DSM-13087     

Homalodontus nom. nov., a replacement name for Wapitiodus Mutter,de Blanger and Neuman, 2007 (Homalodontidae nom. nov., ?Hybodontoidea), preoccupied by Wapitiodus Orchard, 2005

The replacement names Homalodontus nom. nov. ( Homalodontidae nom. nov. ) are proposed for the Early Triassic shark Wapitiodus Mutter et al., 2007 (Wapitiodidae Mutter et al., 2007), preoccupied by the Triassic conodont Wapitiodus Orchard, 2005 (Gondolellidea Lindström, 1970 ). © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 419–420.     

The Ultramicrobacterium “Elusimicrobium minutum” gen. nov., sp. nov., the First Cultivated Representative of the Termite Group 1 Phylum

Insect intestinal tracts harbor several novel, deep-rooting clades of as-yet-uncultivated bacteria whose biology is typically completely unknown. Here, we report the isolation of the first representative of the termite group 1 (TG1) phylum from sterile-filtered gut homogenates of a humivorous scarab beetle larva. Strain Pei191^T is a mesophilic, obligately anaerobic ultramicrobacterium with a gram-negative cell envelope. Cells are typically rod shaped, but cultures are pleomorphic in all growth phases (0.3 to 2.5 μm long and 0.17 to 0.3 μm wide). The isolate grows heterotrophically on sugars and ferments d-galactose, d-glucose, d-fructose, d-glucosamine, and N-acetyl-d-glucosamine to acetate, ethanol, hydrogen, and alanine as major products but only if amino acids are present in the medium. PCR-based screening and comparative 16S rRNA gene sequence analysis revealed that strain Pei191^T belongs to the “intestinal cluster,” a lineage of hitherto uncultivated bacteria present in arthropod and mammalian gut systems. It is only distantly related to the previously described so-called “endomicrobia” lineage, which comprises mainly uncultivated endosymbionts of termite gut flagellates. We propose the name “Elusimicrobium minutum” gen. nov., sp. nov. (type strain, Pei191^T = ATCC BAA-1559^T = JCM 14958^T) for the first isolate of this deep-branching lineage and the name “Elusimicrobia” phyl. nov. for the former TG1 phylum.Insect intestinal tracts harbor an enormous diversity of as-yet-uncultivated bacteria that are characterized only by their 16S rRNA gene sequences and whose biology is typically completely obscure (9, 17, 49). As in other environments (45), many of these sequences form deep-branching phylogenetic lineages that do not contain a single isolate (18, 28). One of these lineages is the termite group 1 (TG1), which was originally discovered by Ohkuma and Kudo (37) and recognized as a phylum-level group (candidate division) by Hugenholtz et al. (20). TG1 bacteria form a major proportion of the microbial community in the hindgut of lower termites (17, 69), where they inhabit the cytoplasm of the intestinal flagellates (38, 53). These so-called “endomicrobia” are specific for the respective flagellate species (21) and, at least in the case of “Candidatus Endomicrobium trichonymphae,” are cospeciating with their flagellate host (22).However, the TG1 phylum also comprises several other deep-rooting lineages (>15% 16S rRNA gene sequence divergence). They are present in a variety of environments, including soils, sediments, and intestinal tracts (14). One of these lineages, the “intestinal cluster,” comprises sequences originating exclusively from intestinal habitats, including the termite gut, but is only distantly related to the lineage comprising the “endomicrobia” (14). Here, we report the isolation of a member of the intestinal cluster from the hindgut of a humivorous scarab beetle larva and its physiological and ultrastructural characterization. We propose a new species, “Elusimicrobium minutum” gen. nov. sp. nov., and define the phylogenetic framework for the first cultivated representative of the TG1 phylum.     

‘Candidatus ferrigenium straubiae’ sp. nov., ‘Candidatus ferrigenium bremense’ sp. nov., ‘Candidatus ferrigenium altingense’ sp. nov., are autotrophic Fe(II)-oxidizing bacteria of the family Gallionellaceae

Iron(II) [Fe(II)] oxidation coupled to denitrification is recognized as an environmentally important process in many ecosystems. However, the Fe(II)-oxidizing bacteria (FeOB) dominating autotrophic nitrate-reducing Fe(II)-oxidizing enrichment cultures, affiliated with the family Gallionellaceae, remain poorly taxonomically defined due to lack of representative isolates. We describe the taxonomic classification of three novel FeOB based on metagenome-assembled genomes (MAGs) acquired from the autotrophic nitrate-reducing enrichment cultures KS, BP and AG. Phylogenetic analysis of nearly full-length 16S rRNA gene sequences demonstrated that these three FeOB were most closely affiliated to the genera Ferrigenium, Sideroxydans and Gallionella, with up to 96.5%, 95.4% and 96.2% 16S rRNA gene sequence identities to representative isolates of these genera, respectively. In addition, average amino acid identities (AAI) of the genomes compared to the most closely related genera revealed highest AAI with Ferrigenium kumadai An22 (76.35–76.74%), suggesting that the three FeOB are members of this genus. Phylogenetic analysis of conserved functional genes further supported that these FeOB represent three novel species of the genus Ferrigenium. Moreover, the three novel FeOB likely have characteristic features, performing partial denitrification coupled to Fe(II) oxidation and carbon fixation. Scanning electron microscopy of the enrichment cultures showed slightly curved rod-shaped cells, ranging from 0.2-0.7 μm in width and 0.5–2.3 μm in length. Based on the phylogenetic, genomic and physiological characteristics, we propose that these FeOB represent three novel species, ‘Candidatus Ferrigenium straubiae’ sp. nov., ‘Candidatus Ferrigenium bremense’ sp. nov. and ‘Candidatus Ferrigenium altingense’ sp. nov. that might have unique metabolic features among the genus Ferrigenium.     

Rhodoferax fermentans gen. nov., sp. nov., a phototrophic purple nonsulfur bacterium previously referred to as the “Rhodocyclus gelatinosus-like” group

Strains of the phototrophic bacteria previously referred to as the rhodocyclus gelatinosus-like (RGL) group were taxonomically studied in comparison with Rhodocyclus species. Cells of the RGL strains were curved rods and motile by means of polar flagella. They contained bacteriochlorophyll a and carotenoids of the spheroidene series. The intracytoplasmic membrane system was absent. Photoorganotropho with various organic compounds as carbon sources was the preferred mode of growth. Aerobic growth at full atmospheric oxygen tension and fermentative growth under anaerobic-dark conditions were also possible. The major cellular fatty acids were palmitoleic acid and palmitic acid, and 3-hydroxylated fatty acids with octanoic acid predominating were also found. Both ubiquinone-8 and rhodoquinone-8 occurred as major quinones. The mol% guanine plus cytosine of the DNAs varied between 59.8 and 60.3. DNA-DNA hybridization studies showed that the RGL strains were highly related to each other but exhibited low levels of the homology to Rhodocyclus species. These data allow the establishment of the RGL group as a new taxon of the purple nonsulfur bacteria, for which the name Rhodoferax fermentans gen. nov., sp. nov. is proposed.     

Morphology and cell division of the oxytrichids Architricha indica nov. gen., nov. sp., and Histriculus histrio (Müller, 1773), Corliss, 1960 (Ciliophora, Hypotrichida)

The oxytrichid ciliate Architricha indica nov. gen., nov. sp., isolated from the river Yamuna, Delhi, shows a new combination of characters. It possesses a flexible body, 18 frontal-ventral-transverse (FVT) cirri, 3 right and 2 left marginal cirral rows, 6 dorsal bristle rows and 3 caudal cirri (CC). The FVT cirri arise from 6 primordia, which utilize 6 parental cirri in their origin as is typical of Oxytricha species. Multiple marginal rows (MMR) develop through 5 independent marginal primordia arising "within-row", 1 in each parental marginal row. All the 5 marginal rows are thus morphogenetically active. Such a mode of formation of MMR has not been recorded among oxytrichids and has necessitated separation of A. indica at the generic level. Histriculus, on the other hand, has well-known characteristics, viz. rigid body, confluent marginal rows and absence of CC. The morphogenesis of Histriculus histrio has been described by Berger and Foissner [1997. Cladistic relationships and generic characterization of oxytrichid hypotrichs (Protozoa, Ciliophora). Arch. Protistenkd. 148, 125-155]. Reinvestigation of very early stages of development revealed that (i) the FVT cirral primordia utilize kinetosomes from 5 parental FVT cirri, (ii) the primordium II of the proter is of a composite origin: kinetosomes from the oral primordium merge with the primordium II that originates from the buccal cirrus II/2 and (iii) the FVT primordia V and VI for the 2 daughter cells arise sequentially from the parental cirrus V/4. Thus, the genus Histriculus exhibits a new combination of characters with respect to the origin of FVT cirri, an additional pattern to be added to the known 6 patterns of FVT development in oxytrichids [Berger and Foissner, 1997; Berger, H., 1999. Monograph of the Oxytrichidae (Ciliophora, Hypotrichida), Kluwer Academic Publishers, Dordrecht/Boston/London].     

‘Cand. Actinochlamydia clariae’ gen. nov., sp. nov., a Unique Intracellular Bacterium Causing Epitheliocystis in Catfish (Clarias gariepinus) in Uganda

Background and Objectives

Epitheliocystis, caused by bacteria infecting gill epithelial cells in fish, is common among a large range of fish species in both fresh- and seawater. The aquaculture industry considers epitheliocystis an important problem. It affects the welfare of the fish and the resulting gill disease may lead to mortalities. In a culture facility in Kampala, Uganda, juveniles of the African sharptooth catfish (Clarias gariepinus) was observed swimming in the surface, sometimes belly up, showing signs of respiratory problems. Histological examination of gill tissues from this fish revealed large amounts of epitheliocysts, and also presence of a few Ichthyobodo sp. and Trichodina sp.

Methods and Results

Sequencing of the epitheliocystis bacterium 16S rRNA gene shows 86.3% similarity with Candidatus Piscichlamydia salmonis causing epitheliocystis in Atlantic salmon (Salmo salar). Transmission electron microscopy showed that the morphology of the developmental stages of the bacterium is similar to that of members of the family Chlamydiaceae. The similarity of the bacterium rRNA gene sequences compared with other chlamydia-like bacteria ranged between 80.5% and 86.3%. Inclusions containing this new bacterium have tubules/channels (termed actinae) that are radiating from the inclusion membrane and opening on the cell surface or in neighbouring cells.

Conclusions

Radiation of tubules/channels (actinae) from the inclusion membrane has never been described in any of the other members of Chlamydiales. It seems to be a completely new character and an apomorphy. We propose the name Candidatus Actinochlamydia clariae gen. nov., sp. nov. (Actinochlamydiaceae fam. nov., order Chlamydiales, phylum Chlamydiae) for this new agent causing epitheliocystis in African sharptooth catfish.     

‘Candidatus Megaira polyxenophila’ gen. nov., sp. nov.: Considerations on Evolutionary History,Host Range and Shift of Early Divergent Rickettsiae

“Neglected Rickettsiaceae” (i.e. those harboured by non-hematophagous eukaryotic hosts) display greater phylogenetic variability and more widespread dispersal than pathogenic ones; yet, the knowledge about their actual host range and host shift mechanism is scarce. The present work reports the characterization following the full-cycle rRNA approach (SSU rRNA sequence, specific in situ hybridization, and ultrastructure) of a novel rickettsial bacterium, herewith proposed as ''Candidatus Megaira polyxenophila'' gen. nov., sp. nov. We found it in association with four different free-living ciliates (Diophrys oligothrix, Euplotes octocarinatus, Paramecium caudatum, and Spirostomum sp., all belonging to Alveolata, Ciliophora); furthermore it was recently observed as intracellular occurring in Carteria cerasiformis and Pleodorina japonica (Chlorophyceae, Chlorophyta). Phylogenetic analyses demonstrated the belonging of the candidate new genus to the family Rickettsiaceae (Alphaproteobacteria, Rickettsiales) as a sister group of the genus Rickettsia. In situ observations revealed the ability of the candidate new species to colonize either nuclear or cytoplasmic compartments, depending on the host organism. The presence of the same bacterial species within different, evolutionary distant, hosts indicates that ''Candidatus Megaira polyxenophila'' recently underwent several distinct host shifts, thus suggesting the existence of horizontal transmission pathways. We consider these findings as indicative of an unexpected spread of rickettsial infections in aquatic communities, possibly by means of trophic interactions, and hence propose a new interpretation of the origin and phylogenetic diversification of rickettsial bacteria.     

Ambrosiozyma kamigamensis sp. nov. and A. neoplatypodis sp. nov., two new ascomycetous yeasts from ambrosia beetle galleries

Two new yeast species of the genus Ambrosiozyma are described on the basis of comparison of nucleotide sequences of large subunit of ribosomal DNA D1/D2 region. Ambrosiozyma kamigamensis and Ambrosiozyma neoplatypodis differ from Ambrosiozyma ambrosiae by 17 nucleotides (3.0%) and 16 nucleotides (2.8%), respectively, out of 565. The two species differ from each other by 13 nucleotides. Ambrosiozyma kamigamensis was isolated from galleries of the ambrosia beetle, Platypus quercivorus, in specimens of Quercus laurifolia and Castanopsis cuspidata located in the southern part of Kyoto, Japan. Ambrosiozyma neoplatypodis was isolated from similar material, but only in Q. laurifolia. Ambrosiozyma kamigamensis can be distinguished from the other Ambrosiozyma species by the inability to assimilate erythritol, whereas A. neoplatypodis can be distinguished by the ability to assimilate both L: -arabinose and nitrate. The type strains of A. kamigamensis and A. neoplatypodis are JCM 14990(T) (=CBS 10899(T)) and JCM 14992(T) (=CBS 10900(T)), respectively. This is the first report of new Ambrosiozyma species since the genus was proposed.