Isolation and sequence analysis of pCS36-4CPA, a small plasmid from Citrobacter sp. 36-4CPA.

A small plasmid designated pCS36-4CPA with a size of 5217 base pairs and G-C content of 50.74% was isolated from Citrobacter sp. 36-4CPA. The origin of replication (ori) of the plasmid was identified as a region of about 800 bp in length with an identity of 67.1% to the ColE1 plasmid at the nucleotide level. The replication region contained typical elements of ColE1-like plasmids: RNA I and RNA II with their corresponding -10 and -35 boxes, a single-strand initiation site (ssi), and a lagging-strand termination site (terH). As seen in other ColE1-like plasmids, pCS36-4CPA carried mobilisation machinery that include mobABCD genes but it did not possess the rom gene. Analysis of the multimer resolution site (mrs) was performed and XerC and XerD binding sites were identified. Also, the 70-nt transcript Rcd of pCS36-4CPA was predicted and similarity of the transcript's secondary structure with those of the ColE1-family was shown. The cargo module of pCS36-4CPA contained three open reading frames (ORFs). Two of them (ORF5 and ORF6) showed no significant homology to any known gene sequences but contained putative THAP DNA-binding (DBD) and type II restriction endonuclease EcoO109I domains. The seventh open reading frame (ORF7) encodes YhdJ-like DNA modification methylase. The region highly homologous to pCS36-4CPA was found in the Salmonella phage SE2 genome.

Benthic phototrophic community from Kiran soda lake, south-eastern Siberia.

Phototrophic bacterial mats from Kiran soda lake (south-eastern Siberia) were studied using integrated approach including analysis of the ion composition of water, pigments composition, bacterial diversity and the vertical distribution of phototrophic microorganisms in the mats. Bacterial diversity was investigated using microscopic examination, 16S rRNA gene Illumina sequencing and culturing methods. The mats were formed as a result of decomposition of sedimented planktonic microorganisms, among which cyanobacteria of the genus Arthrospira predominated. Cyanobacteria were the largest part of phototrophs in the mats, but anoxygenic phototrophs were significant fraction. The prevailing species of the anoxygenic phototrophic bacteria are typical for soda lakes. The mats harbored aerobic anoxygenic phototrophic bacteria, purple sulfur and non-sulfur bacteria, as well as new filamentous phototrophic Chloroflexi. New strains of Thiocapsa sp. Kir-1, Ectothiorhodospira sp. Kir-2 and Kir-4, Thiorhodospira sp. Kir-3 and novel phototrophic Chloroflexi bacterium Kir15-3F were isolated and identified.

Chloroflexus islandicus sp. nov., a thermophilic filamentous anoxygenic phototrophic bacterium from a geyser.

A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5-7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as ß- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA-DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus. On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus, with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).

Microbial processes of the carbon and sulfur cycles in an ice-covered, iron-rich meromictic lake Svetloe (Arkhangelsk region, Russia).

Biogeochemical, isotope geochemical and microbiological investigation of Lake Svetloe (White Sea basin), a meromictic freshwater was carried out in April 2014, when ice thickness was ∼0.5 m, and the ice-covered water column contained oxygen to 23 m depth. Below, the anoxic water column contained ferrous iron (up to 240 µµM), manganese (60 µM), sulfide (up to 2 µM) and dissolved methane (960 µM). The highest abundance of microbial cells revealed by epifluorescence microscopy was found in the chemocline (redox zone) at 23-24.5 m. Oxygenic photosynthesis exhibited two peaks: the major one (0.43 µmol C L-1  day-1 ) below the ice and the minor one in the chemocline zone, where cyanobacteria related to Synechococcus rubescens were detected. The maximum of anoxygenic photosynthesis (0.69 µmol C L-1  day-1 ) at the oxic/anoxic interface, for which green sulfur bacteria Chlorobium phaeoclathratiforme were probably responsible, exceeded the value for oxygenic photosynthesis. Bacterial sulfate reduction peaked (1.5 µmol S L-1  day-1 ) below the chemocline zone. The rates of methane oxidation were as high as 1.8 µmol CH4  L-1  day-1 at the oxi/anoxic interface and much lower in the oxic zone. Small phycoerythrin-containing Synechococcus-related cyanobacteria were probably involved in accumulation of metal oxides in the redox zone.

Draft Genome Sequences of Two Magnetotactic Bacteria, Magnetospirillum moscoviense BB-1 and Magnetospirillum marisnigri SP-1.

We report here the draft genome sequences of two recently isolated magnetotactic species, Magnetospirillum moscoviense BB-1 and Magnetospirillum marisnigri SP-1. The genome of M. moscoviense BB-1 has 4,164,497 bp, 65.2% G+C content, and comprises 207 contigs. The genome of M. marisnigri SP-1 consists of 131 contigs and has a length of 4,619,819 bp and 64.7% G+C content.

Draft Genome Sequence of Chloroflexus sp. Strain isl-2, a Thermophilic Filamentous Anoxygenic Phototrophic Bacterium Isolated from the Strokkur Geyser, Iceland.

We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain's ecological role as a phototrophic bacterium within the bacterial community.

Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus.

Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range.

Strain Improvement of Streptomyces xanthochromogenes RIA 1098 for Enhanced Pravastatin Production at High Compactin Concentrations.

Pravastatin is one of the most popular cholesterol-lowering drugs. Its industrial production represents a two-stage process including the microbial production of compactin and its further biocatalytic conversion to pravastatin. To increase a conversion rate, a higher compactin content in fermentation medium should be used; however, high compactin concentrations inhibit microbial growth. Therefore, the improvement of the compactin resistance of a producer still remains a relevant problem. A multi-step random UV mutagenesis of a Streptomyces xanthochromogenes strain RIA 1098 and the further selection of high-yield compactin-resistant mutants have resulted in a highly productive compactin-resistant strain S 33-1. After the fermentation medium improvement, the maximum bioconversion rate of this strain has reached 91 % at the daily compactin dose equal to 1 g/L and still remained high (83 %) even at the doubled dose (2 g/L). A 1-year study of the mutant strain stability has proved a stable inheritance of its characteristics that provides this strain to be very promising for the pravastatin-producing industry.

Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia).

Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus-like bacteria was detected in the Baikal rift zone.

Fuchsiella ferrireducens sp. nov., a novel haloalkaliphilic, lithoautotrophic homoacetogen capable of iron reduction, and emendation of the description of the genus Fuchsiella.

Two strains of haloalkaliphilic homoacetogenic bacteria capable of iron reduction, Z-7101T and Z-7102, were isolated from soda lake Tanatar III (Altai, Russia). Cells of both strains were flexible, motile, Gram-negative, spore-forming rods. The strains were mesophilic and obligately alkaliphilic: the pH range for growth was 8.5-10.2 (pHopt 9.8). Growth depended on carbonate and chloride ions. The strains were able to grow chemolithoautotrophically on H2+CO2, producing acetate as the only metabolic product. In medium with carbonates as the only potential electron acceptor, the following substrates were utilized for chemo-organotrophic growth: pyruvate, lactate, ethanol, 1-propanol, ethylene glycol and 1-butanol. Strain Z-7101T was able to reduce nitrate, selenate, thiosulfate and anthraquinone 2,6-disulfonate with ethanol as an electron donor. It was also able to reduce synthesized ferrihydrite to siderite with molecular hydrogen or organic compounds, including acetate and formate, as electron donors. It was able to reduce S0 with acetate or formate as electron donors. The DNA G+C content of strain Z-7101T was 34.6 mol%. 16S rRNA gene sequence analysis showed that strains Z-7101T and Z-7102 were members of the order Halanaerobiales and family Halobacteroidaceae, clustering with Fuchsiella alkaliacetigena Z-7100T (98.9-98.4% similarity). DNA-DNA hybridization was 63.0% between strain Z-7101T and F. alkaliacetigena Z-7100T. Based on morphological and physiological differences from F. alkaliacetigena Z-7100T and the results of phylogenetic analysis and DNA-DNA hybridization, it is proposed to assign strains Z-7101T and Z-7102 ( = DSM 26052 = VKM B-2790) to the novel species Fuchsiellaferrireducens sp. nov. The type strain is strain Z-7101T ( = DSM 26031T = VKM B-2766T).

Reconstruction of bacteriochlorophyll biosynthesis pathways in the filamentous anoxygenic phototrophic bacterium Oscillochloris trichoides DG-6 and evolution of anoxygenic phototrophs of the order Chloroflexales.

It is commonly accepted that green filamentous anoxygenic phototrophic (FAP) bacteria are the most ancient representatives of phototrophic micro-organisms. Modern FAPs belonging to the order Chloroflexales are divided into two suborders: Chloroflexineae and Roseiflexineae. Representatives of Roseiflexineae lack chlorosomes and synthesize bacteriochlorophyll a, whereas those of Chloroflexineae synthesize bacteriochlorophylls a and c and utilize chlorosomes for light harvesting. Though they constitute a small number of species, FAPs are quite diverse in their physiology. This bacterial group includes autotrophs and heterotrophs, thermophiles and mesophiles, aerobes and anaerobes, occupying both freshwater and halophilic environments. The anaerobic mesophilic autotroph Oscillochloris trichoides DG-6 is still not well studied in its physiology, and its evolutionary origin remains unclear. The goals of this study included identification of the reaction centre type of O. trichoides DG-6, reconstruction of its bacteriochlorophyll biosynthesis pathways, and determination of its evolutionary relationships with other FAPs. By enzymic and genomic analysis, the presence of RCII in O. trichoides DG-6 was demonstrated and the complete gene set involved in biosynthesis of bacteriochlorophylls a and c was established. We found that the bacteriochlorophyll gene sets differed between aerobic and anaerobic FAPs. The aerobic FAP genomes code oxygen-dependent AcsF cyclases, but lack the bchQ/bchR genes, which have been associated with adaptation to low light conditions in the anaerobic FAPs. A scenario of evolution of FAPs belonging to the order Chloroflexales is proposed.

Optimized method for preparation of IgG-binding bacterial magnetic nanoparticles.

In this study, the optimized method for designing IgG-binding magnetosomes based on integration of IgG-binding fusion proteins into magnetosome membrane in vitro is presented. Fusion proteins Mbb and Mistbb consisting of magnetosome membrane protein MamC and membrane associating protein Mistic from Bacillus subtilis as anchors and BB-domains of Staphylococcus aureus protein A as IgG-binding region were used. With Response Surface Methodology (RSM) the highest level of proteins integration into magnetosome membrane was achieved under the following parameters: pH 8.78, without adding NaCl and 55 s of vortexing for Mbb; pH 9.48, 323 mM NaCl and 55 s of vortexing for Mistbb. Modified magnetosomes with Mbb and Mistbb displayed on their surface demonstrated comparable levels of IgG-binding activity, suggesting that both proteins could be efficiently used as anchor molecules. We also demonstrated that such modified magnetosomes are stable in PBS buffer during at least two weeks. IgG-binding magnetosomes obtained by this approach could serve as a multifunctional platform for displaying various types of antibodies.

Draft Genome Sequence of Magnetospirillum sp. Strain SO-1, a Freshwater Magnetotactic Bacterium Isolated from the Ol'khovka River, Russia.

Here, we present the draft genome sequence of Magnetospirillum sp. strain SO-1, a freshwater magnetotactic spirillum isolated from the sediments of the Ol'khovka River, Russia.

Natranaerobaculum magadiense gen. nov., sp. nov., an anaerobic, alkalithermophilic bacterium from soda lake sediment.

An obligately alkaliphilic, anaerobic, thermo- and halotolerant, spore-forming bacterium was isolated from sediments of soda lake Magadi (Kenya) and designated strain Z-1001(T). Cells of strain Z-1001(T) were straight, Gram-positive rods, slowly motile. Strain Z-1001(T) was found to be an obligate anaerobe. It grew within a pH range from 7.5 to 10.7 with an optimum at 9.25-9.5 (at 40 °C), a temperature range from 20 to 57 °C with an optimum at 45-50 °C, and a NaCl concentration range from 0 to 1.55 M with an optimum at 1.2-1.4 M. Peptides, such as meat and yeast extracts, peptone and tryptone, were fermented by Z-1001(T). Carbohydrates did not support growth. With yeast extract as an electron donor, strain Z-1001(T) reduced S(2)O(3)(2-), NO(-)(3), AsO(3-)(4), Fe(III) citrate and anthraquinone-2,6-disulfonate (AQDS) as electron acceptors. The isolate was able to grow oligotrophically with a very small amount of yeast extract: 0.03 g l(-1). The main fatty acids were C16 : 0, C16 : 1ω7c, C18 : 0 and C18 : 1ω9. The DNA G+C content of the isolate was 35.6 mol%. 16S rRNA gene sequence analysis showed that strain Z-1001(T) is a member of family Natranaerobiaceae, clustering with the type strain of Natranaerobius thermophilus (95.8-96.0 % sequence similarity). On the basis of physiological and phylogenetic data it is proposed that strain Z-1001(T) ( = DSM 24923(T) = VKM B-2666(T)) represents a novel genus and species, Natranaerobaculum magadiense gen. nov., sp. nov.

Haloferax chudinovii sp. nov., a halophilic archaeon from Permian potassium salt deposits.

Three pigmented strains of halophilic archaea (RS75, RS77, RS79) were isolated from the monoliths of mottled sylvinite from the Verkhnekamsk salt deposit (Solikamsk, Russia). The cells were nonmotile, gram-negative, pleomorphic, disk-shaped or ovoid, 0.8-1.0 × 1.5-2.5 µm. The organism was a chemoorganotrophic obligate aerobe producing catalase and oxidase. A number of carbohydrates and carboxylic acids were used as growth substrates. Growth occurred in the presence of 7-27% NaCl (with the optimum at 15-18%), 0.02-20% KCl (0.2-1%), 0.2-16% MgCl2 (2-3%), in the temperature range from 23 to 51 °C (40-45 °C), and pH 5.5-8.0 (6.8-7.0). The membranes contained carotenoids of the bacterioruberin series. Phosphatidylglyceromethylphosphate (PGP-Me), phosphatidylglycerol (PG), sulfated diglycosyl diether (S-DGD-1) predominated among the polar lipids. The DNA G + C content was 64.0-65.0 mol %. Phylogenetic analysis of the 16S rRNA gene sequences showed high similarity of the new strains to Haloferax species: H. denitrificans (99.2%) and H. volcanii (99.1%), H. larsenii (96.9%) and H. elongans (96.6%). DNA-DNA hybridization revealed 93-95% similarity between strain RS75 and strains RS77 and RS79; the similarity levels between strain RS75 and the type strains of Haloferax denitrificans VKM B-1754(T) and Halobacterium salinarum VKM B-1769(T) were 50 and 10%, respectively. According to its phenotypic and genotypic characteristics, the organism was classified as a member of the genus Haloferax, forming a new species with the proposed name Haloferax chudinovii sp. nov. type strain is RS75(T) (=VKPM B-11279(T)).

Properties of the Probiotic Strain Lactobacillus plantarum 8-RA-3 Grown in a Biofilm by Solid Substrate Cultivation Method.

The biofilm formation took place in 48 h within the solid substrate cultivation of Lactobacillus plantarum 8-RA-3 strain on the wheat bran saturated with the MRS medium. The drying of the bran fermented by lactobacilli resulted in a decrease in the number of colony-forming units (CFU) from 23.0 × 10(8) to 6.9 × 10(5) CFU/g in daily samples and to less than 10(4) CFU/g in 2- and 3-day samples. However, according to the fluorescence-based live/dead assay data, more than 40 % of the non-cultured bacteria were viable. As a result of mice kept on a diet with the introduction of bran fermented by Lact. plantarum 8-RA-3 for 72 h into the fodder, a recovery of normal level of intestinal lactobacilli, inhibited by administration of antibiotic was noted. The strain genetically identical to the Lact. plantarum 8-RA-3 was isolated from the feces of these mice. The results indicate that solid substrate cultivated Lact. plantarum 8-RA-3 strain formed a biofilm. Once dried and transferred into a non-cultured state, biofilm cells retained its viability and biological activity.

Genome sequence and analysis of the tuber crop potato.

Potato (Solanum tuberosum L.) is the world's most important non-grain food crop and is central to global food security. It is clonally propagated, highly heterozygous, autotetraploid, and suffers acute inbreeding depression. Here we use a homozygous doubled-monoploid potato clone to sequence and assemble 86% of the 844-megabase genome. We predict 39,031 protein-coding genes and present evidence for at least two genome duplication events indicative of a palaeopolyploid origin. As the first genome sequence of an asterid, the potato genome reveals 2,642 genes specific to this large angiosperm clade. We also sequenced a heterozygous diploid clone and show that gene presence/absence variants and other potentially deleterious mutations occur frequently and are a likely cause of inbreeding depression. Gene family expansion, tissue-specific expression and recruitment of genes to new pathways contributed to the evolution of tuber development. The potato genome sequence provides a platform for genetic improvement of this vital crop.

Draft genome sequence of the anoxygenic filamentous phototrophic bacterium Oscillochloris trichoides subsp. DG-6.

Oscillochloris trichoides is a mesophilic, filamentous, photoautotrophic, nonsulfur, diazotrophic bacterium which is capable of carbon dioxide fixation via the reductive pentose phosphate cycle and possesses no assimilative sulfate reduction. Here, we present the draft genome sequence of Oscillochloris trichoides subsp. DG-6, the type strain of the species, which has permitted the prediction of genes for carbon and nitrogen metabolism and for the light-harvesting apparatus.

Complete sequence of the duckweed (Lemna minor) chloroplast genome: structural organization and phylogenetic relationships to other angiosperms.

The complete nucleotide sequence of the duckweed (Lemna minor) chloroplast genome (cpDNA) was determined. The cpDNA is a circular molecule of 165,955 bp containing a pair of 31,223-bp inverted repeat regions (IRs), which are separated by small and large single-copy regions of 89,906 and 13,603 bp, respectively. The entire gene pool and relative positions of 112 genes (78 protein-encoding genes, 30 tRNA genes, and 4 rRNA genes) are almost identical to those of Amborella trichopoda cpDNA; the minor difference is the absence of infA and ycf15 genes in the duckweed cpDNA. The inverted repeat is expanded to include ycf1 and rps15 genes; this pattern is unique and does not occur in any other sequenced cpDNA of land plants. As in basal angiosperms and eudicots, but not in other monocots, the borders between IRs and a large single-copy region are located upstream of rps19 and downstream of trnH, so that trnH is not included in IRs. The model of rearrangements of the chloroplast genome during the evolution of monocots is proposed as the result of the comparison of cpDNA structures in duckweed and other monocots. The phylogenetic analyses of 61 protein-coding genes from 38 plastid genome sequences provided strong support for the monophyly of monocots and position of Lemna as the next diverging lineage of monocots after Acorales. Our analyses also provided support for Amborella as a sister to all other angiosperms, but in the bayesian phylogeny inference based on the first two codon positions Amborella united with Nymphaeales.

Occurrence, phylogeny and evolution of ribulose-1,5-bisphosphate carboxylase/oxygenase genes in obligately chemolithoautotrophic sulfur-oxidizing bacteria of the genera Thiomicrospira and Thioalkalimicrobium.

The occurrence of the different genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), the key enzyme of the Calvin-Benson-Bassham cycle of autotrophic CO(2) fixation, was investigated in the members of the genus Thiomicrospira and the relative genus Thioalkalimicrobium, all obligately chemolithoautotrophic sulfur-oxidizing Gammaproteobacteria. The cbbL gene encoding the 'green-like' form I RubisCO large subunit was found in all analysed species, while the cbbM gene encoding form II RubisCO was present only in Thiomicrospira species. Furthermore, species belonging to the Thiomicrospira crunogena 16S rRNA-based phylogenetic cluster also possessed two genes of green-like form I RubisCO, cbbL-1 and cbbL-2. Both 16S-rRNA- and cbbL-based phylogenies of the Thiomicrospira-Thioalkalimicrobium-Hydrogenovibrio group were congruent, thus supporting its monophyletic origin. On the other hand, it also supports the necessity for taxonomy reorganization of this group into a new family with four genera.