Peter Hirsch

Deinococcus frigens sp. nov., Deinococcus saxicola sp. nov., and Deinococcus marmoris sp. nov., low temperature and draught-tolerating, UV-resistant bacteria from continental Antarctica.

Six Gram-positive, non-motile, UV- and draught-tolerant bacteria were isolated from antarctic soil and rock samples. The pink to orange cocci grew well on oligotrophic medium PYGV (pH 7.5) at 9-18 degrees C. They tolerated 0-10% NaCl, were aerobic to facultatively anaerobic and contained ornithine in their cell wall (type A3beta, Orn-Gly2). The lipid profiles of four strains were found to be typical for those of D. radiodurans. Major fatty acids were 16:1cis9, 15:1cis9, 17:1cis9 and i17:1cis9, the respiratory quinone of three strains was MK-8. Comparative 16S rDNA gene sequencing revealed phylogenetic relationships to the Deinococcus clade, especially to D. radiopugnans. The levels of 16S rRNA gene sequence similarity and DNA-DNA hybridisation data showed the six isolates represented new taxa. Phenotypic properties supported the description of three new species which were different from the eight known Deinococcus species and particularly from D. radiopugnans. Soil isolate AA-692T (DSM 12807T) is the type strain of Deinococcus frigens sp. nov., with AA-752 (DSM 15993) and AA-829 (DSM 15994) as additional strains from soil. The endolithic isolate AA-1444T, Deinococcus saxicola sp. nov., (DSM 15974T) came from antarctic sandstone, and Deinococcus marmoris sp. nov. (isolate AA-63T [DSM 12784T]) as well as AA-69 (DSM 15951) were isolated from antarctic marble.

Biomass and organic acids in sandstone of a weathering building: Production by bacterial and fungal isolates

Ten fungal and nine bacterial strains were isolated from a weathering sandstone building. Their growth, organic acid production, and acidification capacity were assessed in culture under nutritional conditions similar to those in situ. Biomass (10–50 nmol phospholipid-PO4g−1) within the rock was small compared to soils. The isolated organisms were able to produce high amounts of those acids found in the sandstone, but acid production did not cause a drastic reduction in culture pH. It is suggested that the importance of acidification in microbial degradation of sandstone has been overestimated and that, under in situ pH and nutritional conditions, cation chelation by microbially produced organic acid anions may be more relevant to the weathering process.

Cryptoendolithic microorganisms from Antarctic sandstone of Linnaeus Terrace (Asgard Range): diversity, properties and interactions

Cryptoendolithic microorganisms from stratified communities in Antarctic sandstone were studied for physiological diversity and possible interactions. Cultures of 25 bacteria, five fungi, and two green algae from one boulder grew with a wide variety of organic carbon or nitrogen sources, they exhibited varied exoenzymatic activities and were psychrophilic or psychrotrophic. Many isolates excreted vitamins into the medium and were stimulated by other vitamins. Organic acid excretion and siderophore formation were common, but antibiotic activity was rare. Plasmids were found in 24% of the bacteria, and many of these strains showed resistance to antibiotics and heavy metals. A small plasmid (2.9 kb) from strain AA-341 was electrotransferred into sensitive isolates, thereby rendering these resistant to amplicillin and Cr3+ Bacterial cultures in spent algal medium and coculture with algae demonstrated beneficial (rarely inhibitory) interactions. A search for free organic compounds in zones of the sandstone community revealed sugars, sugar alcohols, organic acids and amino acids-in many cases the same compounds that were excreted into the laboratory medium. Data presented here indicate low taxonomic but high physiological diversity among these heterotrophic cryptoendoliths. This physiological diversity, as well as the spatial separation in layers with distinct activities, allows coexistence within the community and contributes to the stability of this ecosystem.

Cryptoendolithic actinomycetes from antarctic sandstone rock samples: Micromonospora endolithica sp. nov. and two isolates related to Micromonospora coerulea jensen 1932

Three cryptoendolithic, aerobic actinomycetes (AA-459T, AA-319 and AA-321) from antarctic sandstone were characterised phenotypically and by molecular taxonomic methods. The isolates had single spores on substrate mycelium, meso-diaminopimelic acid (m-DAP) and glycine (cell wall type II), a whole cell sugar pattern D (galactose, xylose, arabinose, glucose or rhamnose) and phospholipids of type PII (diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol). Their predominant fatty acids were iso-16:0 and iso-15:0 or 17:1omega8c, the menaquinone profile was complex with mainly MK10 (H4) and MK10 (H6). A wide variety of sugars and several acids were utilised for growth. The isolates were sensitive to a few antibiotics, but formation and excretion of antibiotics was not observed. Phenotypically, isolates AA-319 and AA-321 were similar. Phylogenetic analysis of 16S rRNA gene sequences revealed close relationship of strains AA-319 and AA-321 with each other (99.5%) and clustering (98.5%) with Micromonospora coerulea DSM 43143T. DNA-DNA hybridisation showed both strains to be genomically highly similar to strain DSM 43143T. Phenotypically they could be viewed as separate taxa, but presently they will be considered as strains of Micromonospora coerulea. Strain AA-459T was phylogenetically close to Micromonospora chersina DSM 44151T (99.1%) and to Micromonospora rosaria DSM 803T, but DNA-DNA similarity with M. chersina DSM 44151T was low with 28.9/33.5 %, indicating the presence of a different and new species. Consequently, isolate AA-459T (DSM 44398T NRRL B-24248T) is described as the type strain of Micromonospora endolithica sp. nov.

The phylogenetic position of the budding bacteria Blastobacter aggregatus and Gemmobacter aquatilis gen., nov. sp. nov.

Blastobacter aggregatus and a Blastobacter-like isolate (IFAM 1031) were analysed by the 16S ribosomal RNA cataloguing approach in order to determine their phylogenetic position. Both phenotypical similar organisms are members of the alpha-subdivision of purple phototrophic bacteria and their non-phototrophic relatives but they are not closely related: B. aggregatus clusters with Agrobacterium tumefaciens and Rhizobium species; the unnamed strain displays a moderate relationship to members of Rhodobacter and Paracoccus denitrificans, with which is shares the character of a nicked 23S rRNA. Although the budding isolate IFAM 1031 resembles members of Blastobacter phenotypically, in the broad DNA G+C content and in the fatty acid pattern, a unique set of characters was found which allows description of the isolate as the typus of a new genus for which Gemmobacter gen. nov. is proposed, with G. aquatilis sp. nov. as the type species. G. aquatilis harbors at least two plasmids of different size and unknown function.

Photosynthesis‐based microbial communities on two churches in northern Germany: Weathering of granite and glazed brick

Abstract Microbial communities on two churches in Schleswig‐Holstein (northern Germany) were characterized using cultural methods as well as light and scanning electron microscopy. Dilution‐plate counts of fungi [106/g dry weight (gdw) stone] and heterotrophic bacteria (105/gdw) were as high as those reported for soils. Counts of algae (106/gdw) were somewhat higher than those for soils. Biomass expressed as phospholipid phosphate concentration (PLP; 115–137 nmol PLP/gdw) was nearly 10 times that of Antarctic sandstone, at least twice that in an architectural red sandstone, and approached that found in soils. Amounts of chlorophyll a were higher than those for the Antarctic sandstone (known to contain algae and cyanobacteria) and were at the lower end of the range reported for soils. The high biomass is supported by photosynthetic carbon input, and hypotheses are presented that describe the role of these epi‐ and endolithic communities in the weathering of their substrata.

Chemotaxonomic Investigation of Budding and/or Hyphal Bacteria

Summary Hyphal and/or budding bacteria were studied using quinones, phospholipids, and fatty acids as chemotaonomic markers. Most suitable for strain discrimination were phospholipids and hydroxy fatty acids. New derivatives, O-nicotinoyl-hydroxy fatty acid methylesters, were employed for structure determination of 2-hydroxy fatty acids by gas chromatography / mass spectrometry. 96 bacterial strains from the culture collection of the Institut fur Allgemeine Mikrobiologie (IfAM), Kiel, were analyzed with respect to their lipid constituents. The existing classification into genera could be largely confirmed. Morphologically very similar strains of Hyphomicrobium and Hirschia differed markedly in quinone-, phospholipid-, and hydroxy fatty acid composition. Unusual long-chain hydroxy fatty acids were detected in Hyphomicrobium and morphologically similar organisms. Among the Blastobacter -like strains, one strain, IfAM 1027, was excluded from the genus Blastobacter . The hyphomonads were rather heterogeneous which lead to their division into subgroups. The conformity of chemotaxonomic data for these budding and/or hyphal bacteria with the phylogenetic position deducted from 16S rRNA sequence analyses of the literature is discussed.

Saccharospirillum impatiens gen. nov., sp nov., a novel gamma-Proteobacterium isolated from hypersaline Ekho Lake (East Antarctica)

Five Gram-negative, motile, aerobic to microaerophilic spirilla were isolated from various depths of the hypersaline, heliothermal and meromictic Ekho Lake (East Antarctica). The strains are oxidase- and catalase-positive, metabolize a variety of sugars and carboxylic acids and have an absolute requirement for sodium ions. The predominant fatty acids of the organisms are C(16 : 1)omega7c, C(16 : 0) and C(18 : 1)omega7c, with C(10 : 1))3-OH, C(10 : 0) 3-OH, C(12 : 0) 3-OH, C(14 : 1)3-OH, C(14 : 0) 3-OH and C(19 : 1) present in smaller amounts. The main polar lipids are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylmonomethylamine. The DNA base composition of the strains is 54-55 mol% G + C. 16S rRNA gene sequence comparisons show that the isolates are related to the genera Oceanospirillum, Pseudospirillum, Marinospirillum, Halomonas and Chromohalobacter in the gamma-Proteobacteria. Morphological, physiological and genotypic differences from these previously described genera support the description of a novel genus and species, Saccharospirillum impatiens gen. nov., sp. nov. The type strain is EL-105(T) (=DSM 12546(T) = CECT 5721(T)).

Differentiation of newly described antarctic bacterial isolates related to Roseobacter species based on 16S-23S rDNA internal transcribed spacer sequences.

The 16S-23S rDNA internal transcribed spacer (ITS) of Roseobacter denitrificans, Roseobacter litoralis, Ruegeria algicola and strains of the recently described species Antarctobacter heliothermus and Roseovarius tolerans were analysed in order to examine DNA sequence variations and to draw conclusions about inter- and intraspecific relationships. A. heliothermus included four strains with an ITS fragment length of 1092 bp. Roseovarius tolerans was described on the basis of eight strains. Five of these harboured two ITS fragments of different lengths (959 and about 1100 bp), while the others had one fragment of either 1083 bp (two strains) or 1165 bp (one strain). ITS lengths of the related species Roseobacter denitrificans, Roseobacter litoralis and Ruegeria algicola were found to be 980, 984 and 1158 bp, respectively. Phylogenetic analyses of the DNA sequences allowed species affiliation of strains with sequence length differences of > 200 bp and recognition of relationships based on a well-supported ITS tree. The strains of A. heliothermus and Roseovarius tolerans each formed a monophyletic branch and they were separated from each other by Ruegeria algicola. This species was now clearly separated from Roseobacter denitrificans and Roseobacter litoralis, which corresponded to the new genus affiliation of Ruegeria algicola. These data were additionally supported by analyses of the structure, relative position and order of genes for tRNA(Ile) and tRNA(Ala) found within the ITS of each strain. Comparative DNA sequence analyses of ITS and 16S rDNA revealed limitations, on species and strain levels, with respect to the phylogenetic resolution of the 16S rDNA due to the limited number of informative (variable) sites, while ITS sequence analyses provided more variable and sufficiently conserved positions to discriminate between strains and to reconstruct their taxonomic relationships.

Roseibaca ekhonensis gen. nov., sp. nov., an alkalitolerant and aerobic bacteriochlorophyll a-producing alphaproteobacterium from hypersaline Ekho Lake.

A Gram-negative, aerobic rod was isolated from the hypersaline, heliothermal and meromictic Ekho Lake (East Antarctica) at a depth of 6 m. The novel strain (designated EL-50T) was oxidase-positive and weakly catalase-positive and metabolized a variety of carboxylic acids, alcohols, sugars and lipids. Cells of strain EL-50T had an absolute requirement for artificial seawater or NaCl. Optimum growth occurred at 16 degrees C and at pH values ranging from 7.0 to 9.5. A large in vivo absorption band at 865-866 nm indicated the production of bacteriochlorophyll (bchl) a. The predominant cellular fatty acid of strain EL-50T was 18:1omega7c, with 3-OH 14:1, 16:1omega9c, 16:0 and 18:1omega9c present in lower amounts. Fatty acids 16:0 and 18:1omega9c were probably amide-linked. The main polar lipids were diphosphatidylglycerol, phospatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. Ubiquinone 10 was produced. The cell-wall diamino acid was meso-diaminopimelic acid. The DNA G+C content of strain EL-50T was 61 mol%. 16S rRNA gene sequence comparisons indicated that the novel isolate was phylogenetically most closely related to alkaliphilic Rhodobaca and Roseinatronobacter species (approximately 96% 16S rRNA gene similarity). The organism had no particular relationship to any other cultivated members within the Alphaproteobacteria. The distinct morphological, physiological and genotypic differences from the previously described taxa studied supported the description of a new genus and novel species, for which the name Roseibaca ekhonensis gen. nov., sp. nov. is proposed. The type strain is EL-50T (=DSM 11469T=CECT 7235T).