Association between Taxonomic Composition of Gut Microbiota and Host Single Nucleotide Polymorphisms in Crohn's Disease Patients from Russia.

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease of unknown etiology. Genetic predisposition and dysbiotic gut microbiota are important factors in the pathogenesis of CD. In this study, we analyzed the taxonomic composition of the gut microbiota and genotypes of 24 single nucleotide polymorphisms (SNP) associated with the risk of CD. The studied cohorts included 96 CD patients and 24 healthy volunteers from Russia. Statistically significant differences were found in the allele frequencies for 8 SNPs and taxonomic composition of the gut microbiota in CD patients compared with controls. In addition, two types of gut microbiota communities were identified in CD patients. The main distinguishing driver of bacterial families for the first community type are Bacteroidaceae and unclassified members of the Clostridiales order, and the second type is characterized by increased abundance of Streptococcaceae and Enterobacteriaceae. Differences in the allele frequencies of the rs9858542 (BSN), rs3816769 (STAT3), and rs1793004 (NELL1) were also found between groups of CD patients with different types of microbiota communities. These findings confirm the complex multifactorial nature of CD.

Another blow to the conserved gene order in Annelida: Evidence from mitochondrial genomes of the calcareous tubeworm genus Hydroides.

Mitochondrial genomes are frequently applied in phylogenetic and evolutionary studies across metazoans, yet they are still poorly represented in many groups of invertebrates, including annelids. Here, we report ten mitochondrial genomes from the annelid genus Hydroides (Serpulidae) and compare them with all available annelid mitogenomes. We detected all 13 protein coding genes in Hydroides spp., including the atp8 which was reported as a missing gene in the Christmas Tree worm Spirobranchus giganteus, another annelid of the family Serpulidae. All available mitochondrial genomes of Hydroides show a highly positive GC skew combined with a highly negative AT skew - a feature consistent with that found only in the mitogenome of S. giganteus. In addition, amino acid sequences of the 13 protein-coding genes showed a high genetic distance between the Hydroides clade and S. giganteus, suggesting a fast rate of mitochondrial sequence evolution in Serpulidae. The gene order of protein-coding genes within Hydroides exhibited extensive rearrangements at species level, and were different from the arrangement patterns of other annelids, including S. giganteus. Phylogenetic analyses based on protein-coding genes recovered Hydroides as a monophyletic group sister to Spirobranchus with a long branch, and sister to the fan worm Sabellidae. Yet the Serpulidae + Sabellidae clade was unexpectedly grouped with Sipuncula, suggesting that mitochondrial genomes alone are insufficient to resolve the phylogenetic position of Serpulidae within Annelida due to its high base substitution rates. Overall, our study revealed a high variability in the gene order arrangement of mitochondrial genomes within Serpulidae, provided evidence to question the conserved pattern of the mitochondrial gene order in Annelida and called for caution when applying mitochondrial genes to infer their phylogenetic relationships.

Developmental studies provide new insights into the evolution of sense organs in Sabellariidae (Annelida).

BACKGROUND: Sabellarids, also known as honeycomb or sandcastle worms, when building their tubes, produce chemical signals (free fatty acids) that are responsible for larval settlement and the formation of three-dimensional aggregations. The larval palps and the dorsal hump (becoming the median organ in adults) are presumed to participate in such a substrate selection during settlement. Notably, the sabellariid median organ is an apparently unique organ among annelids that has been attributed with a sensory function and perhaps with some affinities to the nuchal organs of other polychaetes. Nevertheless, detailed investigations of this prominent character complex including ultrastructural examinations are lacking so far. RESULTS: Our comprehensive investigations provide data about the anterior sensory organs in Sabellariidae and inform about their transformation during pelagic larval development. We used a comparative approach including immunostaining with subsequent confocal laser scanning microscopy (clsm), histological sections as well as electron microscopy in a range of larval and adult stages of two sabellariid species. We find that the neuronal innervation as well as the ultrastructure of the sabellariid ciliary structures along the median organ are highly comparable with that of nuchal organs known from other polychaetes. Furthermore, the myoinhibitory protein (MIP) - a protein known to be also involved into chemo-sensation - was detected in the region of the larval median organ. Moreover, we reveal the presence of an unusual type of photoreceptor as part of the median organ in Idanthyrsus australiensis with a corrugated sensory membrane ultrastructure unlike those observed in the segmental ocelli of other polychaetes. CONCLUSIONS: We are describing for the first time the nuchal organ-like structures in different developmental stages of two species of Sabellariidae. The external morphology, neuronal innervation, developmental fate and ultrastructure of the newly-discovered median organ-based ciliary pits are comparable with the characteristics known for annelid nuchal organs and therefore indicate a homology of both sensory complexes. The presence of myoinhibitory peptide (MIP) in the respective region supports such a hypothesis and exhibits the possibility of an involvement of the entire sabellariid median organ complex, and in particular the prominent ciliated pits, in chemo-sensation.

Putative extracellular α-class carbonic anhydrase, EcaA, of Synechococcus elongatus PCC 7942 is an active enzyme: a sequel to an old story.

Carbonic anhydrase (CA) EcaA of Synechococcus elongatus PCC 7942 was previously characterized as a putative extracellular α-class CA, however, its activity was never verified. Here we show that EcaA possesses specific CA activity, which is inhibited by ethoxyzolamide. An active EcaA was expressed in heterologous bacterial system, which supports the formation of disulfide bonds, as a full-length protein (EcaA+L) and as a mature protein that lacks a leader peptide (EcaA-L). EcaA-L exhibited higher specific activity compared to EcaA+L. The recombinant EcaA, expressed in a bacterial system that does not support optimal disulfide bond formation, exhibited extremely low activity. This activity, however, could be enhanced by the thiol-oxidizing agent, diamide; while a disulfide bond-reducing agent, dithiothreitol, further inactivated the enzyme. Intact E. coli cells that overexpress EcaA+L possess a small amount of processed protein, EcaA-L, whereas the bulk of the full-length protein resides in the cytosol. This may indicate poor recognition of the EcaA leader peptide by protein export systems. S. elongatus possessed a relatively low level of ecaA mRNA, which varied insignificantly in response to changes in CO2 supply. However, the presence of protein in the cells is not obvious. This points to the physiological insignificance of EcaA in S. elongatus, at least under the applied experimental conditions.

Barcoding and multi-locus phylogeography of the globally distributed calcareous tubeworm genus Hydroides Gunnerus, 1768 (Annelida, Polychaeta, Serpulidae).

Hydroides is a large and diverse group of calcareous tubeworms (Serpulidae, Annelida) recognised by a distinctive but variable two-tiered operculum. Despite considerable research using several species of Hydroides as models in ecological and biofouling studies, phylogenetic and biogeographic relationships within the genus are still poorly understood. Using combined mitochondrial (COI, cytochrome b) and nuclear (18S, 28S and ITS) gene markers for 284 individuals of 45 morphospecies of Hydroides, we investigated the global phylogenetic and biogeographic relationships within the genus. Phylogenetic topologies were well supported and indicated high genetic diversity within Hydroides, revealing potential cryptic species. Present results also include the first COI barcoding data enabling rapid and effective species identification of Hydroides on a global scale. Phylogenetic relationships within Hydroides were more concordant with geographical distributions than morphological similarity of their opercula. Molecular divergence estimates suggested the origin and subsequent diversification in the western Tethys Sea followed by a shift of the historical centre of diversity from the Indo-Mediterranean region to the central Indo-Pacific during the last 50 million years. Further studies on population genetics of species consisting of multiple lineages would provide a better understanding on the status of potential cryptic species. Furthermore, paleogeographic studies based on fossil Hydroides tubes would provide evidence to test this biogeographic hypothesis.

Genomic Survey and Biochemical Analysis of Recombinant Candidate Cyanobacteriochromes Reveals Enrichment for Near UV/Violet Sensors in the Halotolerant and Alkaliphilic Cyanobacterium Microcoleus IPPAS B353.

Cyanobacteriochromes (CBCRs), which are exclusive to and widespread among cyanobacteria, are photoproteins that sense the entire range of near-UV and visible light. CBCRs are related to the red/far-red phytochromes that utilize linear tetrapyrrole (bilin) chromophores. Best characterized from the unicellular cyanobacterium Synechocystis sp. PCC 6803 and the multicellular heterocyst forming filamentous cyanobacteria Nostoc punctiforme ATCC 29133 and Anabaena sp. PCC 7120, CBCRs have been poorly investigated in mat-forming, nonheterocystous cyanobacteria. In this study, we sequenced the genome of one of such species, Microcoleus IPPAS B353 (Microcoleus B353), and identified two phytochromes and seven CBCRs with one or more bilin-binding cGMP-specific phosphodiesterase, adenylyl cyclase and FhlA (GAF) domains. Biochemical and spectroscopic measurements of 23 purified GAF proteins from phycocyanobilin (PCB) producing recombinant Escherichia coli indicated that 13 of these proteins formed near-UV and visible light-absorbing covalent adducts: 10 GAFs contained PCB chromophores, whereas three contained the PCB isomer, phycoviolobilin (PVB). Furthermore, the complement of Microcoleus B353 CBCRs is enriched in near-UV and violet sensors, but lacks red/green and green/red CBCRs that are widely distributed in other cyanobacteria. We hypothesize that enrichment in short wavelength-absorbing CBCRs is critical for acclimation to high-light environments where this organism is found.

The complete genome of a cyanobacterium from a soda lake reveals the presence of the components of CO2-concentrating mechanism.

At present geological epoch, the carbon concentrating mechanism (CCM) of cyanobacteria represents the obligatory tool for adaptation to low content of CO2 in the atmosphere and for the maintenance of sufficient photosynthetic activity. Functional CCM was found in modern cyanobacteria from different ecological niches. However, the presence of such mechanism in species that inhabit soda lakes is not obvious due to high content of inorganic carbon (C i) in the environment. Here we analyze CCM components that have been identified by sequencing of the whole genome of the alkaliphilic cyanobacterium Microcoleus sp. IPPAS B-353. The composition of the CCM components of Microcoleus is similar to that of 'model' ß-cyanobacteria, freshwater and marine Synechococcus or Synechocystis spp. However, CahB1 protein of Microcoleus, which is the homolog of CcaA, the carboxysomal ß-type carbonic anhydrase (CA) of ß-cyanobacteria, appeared to be the only active CA located in cell envelopes. The conservative regions of CcmM, CahG (a homolog of archeal γ-CAs, Cam/CamH), and ChpX of Microcoleus possess single amino acid substitutions that may cause a lack of CA activities. Unlike model cyanobacteria, Microcoleus induces only one BicA-type bicarbonate transporter in response to C i limitation. The differences in the appearance of CCM components and in their characteristics between alkaliphilic Microcoleus and freshwater or marine cyanobacteria are described. The possible reasons for the maintenance of CCM components in cyanobacteria, which permanently live at high concentrations of C i in soda lakes, are discussed.

Synechocystis mutants defective in manganese uptake regulatory system, ManSR, are hypersensitive to strong light.

High affinity transport of manganese ions (Mn2+) in cyanobacteria is carried by an ABC-type transporter, encoded by the mntCAB operon, which is derepressed by the deficiency of Mn2+. Transcription of this operon is negatively regulated by the two-component system consisting of a sensory histidine kinase ManS and DNA-binding response regulator ManR. In this study, we examined two Synechocystis mutants, defective in ManS and ManR. These mutants were unable to grow on high concentrations of manganese. Furthermore, they were sensitive to high light intensity and unable to recover after short-term photoinhibition. Under standard illumination and Mn2+ concentration, mutant cells revealed the elevated levels of transcripts of genes involved in the formation of Photosystem II (psbA, psbD, psbC, pap-operon). This finding suggests that, in mutant cells, the PSII is sensitive to high concentrations of Mn2+ even at relatively low light intensity.

Anion inhibition study of the ß-carbonic anhydrase (CahB1) from the cyanobacterium Coleofasciculus chthonoplastes (ex-Microcoleus chthonoplastes).

We investigated the catalytic activity and inhibition of the ß-class carbonic anhydrase (CA, EC 4.2.1.1) CahB1, from the relict cyanobacterium Coleofasciculus chthonoplastes (previously denominated Microcoleus chthonoplastes). The enzyme showed good activity as a catalyst for the CO2 hydration, with a kcat of 2.4 × 10(5)s(-1) and a kcat/Km of 6.3 × 10(7)M(-1)s(-1). A range of inorganic anions and small molecules were investigated as inhibitors of CahB1. Perchlorate and tetrafluoroborate did not inhibit the enzyme (KIs >200 mM) whereas selenate and selenocyanide were ineffective inhibitors too, with KIs of 29.9-48.61 mM. The halides, pseudohalides, carbonate, bicarbonate, trithiocarbonate and a range of heavy metal ions-containing anions were submillimolar-millimolar inhibitors (KIs in the range of 0.15-0.90 mM). The best CahB1 inhibitors were N,N-diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid and phenylarsonic acid, with KIs in the range of 8-75 µM, whereas acetazolamide inhibited the enzyme with a KI of 76 nM. This is the first kinetic and inhibition study of a cyanobacterial CA. As these enzymes are widespread in many cyanobacteria, being crucial for the carbon concentrating mechanism which assures substrate to RubisCO for the CO2 fixation by these organisms, a detailed kinetic/inhibition study may be essential for a better understanding of this superfamily of metalloenzymes and for potential biotechnological applications in biomimetic CO2 capture processes.

Spirulina/Arthrospira/Limnospira-Three Names of the Single Organism.

Recent advances in research techniques have enabled rapid progress in the study of spirulina, an ancient edible cyanobacteria. Nowadays, spirulina species are classified into three genera: Spirulina, Arthrospira, and Limnospira. The latter now refers to industrially manufactured spirulina strains. Whole-genome sequencing revealed gene clusters involved in metabolite production, and the physiology of spirulina. Omics technologies demonstrated the absence of hazardous compounds in spirulina cells, confirming the safety of this biomass as a food product. Spirulina is a good source of different chemicals used in food manufacturing, food supplements, and pharmaceuticals. Spirulina's enrichment with inherent biologically active substances makes it a potential supplier of natural products for dietary and pharmaceutical applications. Spirulina is also a prospective component of both terrestrial and space-based life support systems. Here, we review current breakthroughs in spirulina research and clarify fallacies that can be found in both professional literature and public media.

The Freshwater Cyanobacterium Synechococcus elongatus PCC 7942 Does Not Require an Active External Carbonic Anhydrase.

Under standard laboratory conditions, Synechococcus elongatus PCC 7942 lacks EcaASyn, a periplasmic carbonic anhydrase (CA). In this study, a S. elongatus transformant was created that expressed the homologous EcaACya from Cyanothece sp. ATCC 51142. This additional external CA had no discernible effect on the adaptive responses and physiology of cells exposed to changes similar to those found in S. elongatus natural habitats, such as fluctuating CO2 and HCO3- concentrations and ratios, oxidative or light stress, and high CO2. The transformant had a disadvantage over wild-type cells under certain conditions (Na+ depletion, a reduction in CO2). S. elongatus cells lacked their own EcaASyn in all experimental conditions. The results suggest the presence in S. elongatus of mechanisms that limit the appearance of EcaASyn in the periplasm. For the first time, we offer data on the expression pattern of CCM-associated genes during S. elongatus adaptation to CO2 replacement with HCO3-, as well as cell transfer to high CO2 levels (up to 100%). An increase in CO2 concentration coincides with the suppression of the NDH-14 system, which was previously thought to function constitutively.

Identification and functional role of the carbonic anhydrase Cah3 in thylakoid membranes of pyrenoid of Chlamydomonas reinhardtii.

The distribution of the luminal carbonic anhydrase Cah3 associated with thylakoid membranes in the chloroplast and pyrenoid was studied in wild-type cells of Chlamydomonas reinhardtii and in its cia3 mutant deficient in the activity of the Cah3 protein. In addition, the effect of CO(2) concentration on fatty acid composition of photosynthetic membranes was examined in wild-type cells and in the cia3 mutant. In the cia3 mutant, the rate of growth was lower as compared to wild-type, especially in the cells grown at 0.03% CO(2). This might indicate a participation of thylakoid Cah3 in the CO(2)-concentrating mechanism (CCM) of chloroplast and reflect the dysfunction of the CCM in the cia3 mutant. In both strains, a decrease in the CO(2) concentration from 2% to 0.03% caused an increase in the content of polyunsaturated fatty acids in membrane lipids. At the same time, in the cia3 mutant, the increase in the majority of polyunsaturated fatty acids was less pronounced as compared to wild-type cells, whereas the amount of 16:4ω3 did not increase at all. Immunoelectron microscopy demonstrated that luminal Cah3 is mostly located in the thylakoid membranes that pass through the pyrenoid. In the cells of CCM-mutant, cia3, the Cah3 protein was much less abundant, and it was evenly distributed throughout the pyrenoid matrix. The results support our hypothesis that CO(2) might be generated from HCO(3)(-) by Cah3 in the thylakoid lumen with the following CO(2) diffusion into the pyrenoid, where the CO(2) fixing Rubisco is located. This ensures the maintenance of active photosynthesis under CO(2)-limiting conditions, and, as a result, the active growth of cells. The relationships between the induction of CCM and restructuring of the photosynthetic membranes, as well as the involvement of the Cah3 of the pyrenoid in these events, are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

CO2-concentrating mechanism in cyanobacterial photosynthesis: organization, physiological role, and evolutionary origin.

The cellular and molecular organization of the CO2-concentrating mechanism (CCM) of cyanobacteria is reviewed. The primary processes of uptake, translocation, and accumulation of inorganic carbon (Ci) near the active site of carbon assimilation by the enzyme ribulose-1,5-bisphosphate carboxylase in the C3 cycle in cyanobacteria are described as one of the specialized forms of CO2 concentration which occurs in some photoautotrophic cells. The existence of this form of CO2 concentration expands our understanding of photosynthetic Ci assimilation. The means of supplying Ci to the C3 cycle in cyanobacteria is not by simple diffusion into the cell, but it is the result of coordinated functions of high-affinity systems for the uptake of CO2 and bicarbonate, as well as intracellular CO2/HCO3 (-) interconversions by carbonic anhydrases. These biochemical events are under genetic control, and they serve to maintain cellular homeostasis and adaptation to CO2 limitation. Here we describe the organization of the CCM in cyanobacteria with a special focus on the CCM of relict halo- and alkaliphilic cyanobacteria of soda lakes. We also assess the role of the CCM at the levels of the organism, the biosphere, and evolution.

Adapting from Low to High: An Update to CO2-Concentrating Mechanisms of Cyanobacteria and Microalgae.

The intracellular accumulation of inorganic carbon (Ci) by microalgae and cyanobacteria under ambient atmospheric CO2 levels was first documented in the 80s of the 20th Century. Hence, a third variety of the CO2-concentrating mechanism (CCM), acting in aquatic photoautotrophs with the C3 photosynthetic pathway, was revealed in addition to the then-known schemes of CCM, functioning in CAM and C4 higher plants. Despite the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of microalgae and cyanobacteria for the CO2 substrate and low CO2/O2 specificity, CCM allows them to perform efficient CO2 fixation in the reductive pentose phosphate (RPP) cycle. CCM is based on the coordinated operation of strategically located carbonic anhydrases and CO2/HCO3- uptake systems. This cooperation enables the intracellular accumulation of HCO3-, which is then employed to generate a high concentration of CO2 molecules in the vicinity of Rubisco's active centers compensating up for the shortcomings of enzyme features. CCM functions as an add-on to the RPP cycle while also acting as an important regulatory link in the interaction of dark and light reactions of photosynthesis. This review summarizes recent advances in the study of CCM molecular and cellular organization in microalgae and cyanobacteria, as well as the fundamental principles of its functioning and regulation.

A new species of the Spirobranchuskraussii complex, S.akitsushima (Annelida, Polychaeta, Serpulidae), from the rocky intertidal zone of Japan.

A new species of Spirobranchus (Annelida: Serpulidae) is described based on specimens collected at the coastal Shonan area of Sagami Bay and the adjacent areas of Honshu, Japan. Spirobranchusakitsushima sp. nov. forms large aggregations in the intertidal rocky zone of warm-temperate Japanese shores. This species was referred to as Pomatoleioskraussii (Baird, 1864) until the monotypic genus Pomatoleios was synonymized with Spirobranchus. This new species is formally described based on morphologically distinct Japanese specimens with supporting DNA sequence data. The calcareous opercular endplate of Spirobranchusakitsushima sp. nov. lacks a distinct talon, but some specimens have a slight rounded swelling on the endplate underside, while in other species of the S.kraussii complex a talon is present, usually extended, and with bulges. We examined sub-fossil tube aggregations of the new species and suggest that such aggregation stranded ashore is a good indicator of vertical land movements (uplift and subsidence) resulting from past events, such as earthquakes, in Honshu, Japan.

A leader peptide of the extracellular cyanobacterial carbonic anhydrase ensures the efficient secretion of recombinant proteins in Escherichia coli.

Several forms of EcaA protein, correspondent to the extracellular α-class carbonic anhydrase (CA) of cyanobacterium Crocosphaera subtropica ATCC 51142 were expressed in Escherichia coli. The recombinant proteins with no leader peptide (EcaA and its fusion with thioredoxin or glutathione S-transferase) were allocated inside cells in a full-length form; these cells did not display any extracellular CA activity. Soluble proteins (including that of periplasmic space) of E. coli cells that expressed both ЕсаА equipped with its native leader peptide (L-EcaA) as well as L-EcaA fused with thioredoxin or glutathione S-transferase at N-terminus, mainly contained the processed EcaA. The appearance of mature ЕсаА in outer layers of E. coli cells expressed leader peptide-containing forms of recombinant proteins, has been directly confirmed by immunofluorescent microscopy. Those cells also displayed high extracellular CA activity. In addition, the mature EcaA protein was detected in the culture medium. This suggests that cyanobacterial signal peptide is recognized by the secretory machinery and by the leader peptidase of E. coli even as a part of a fusion protein. The efficiency of EcaA leader peptide was comparable to that of PelB and TorA signal peptides, commonly used for biotechnological production of extracellular recombinant proteins in E. coli.

Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil.

The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km(2) and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1) a climate with an important water deficit and poverty in Ca(2+) in both superficial and phreatic waters; and (2) an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.

Laminatubus (Serpulidae, Annelida) from eastern Pacific hydrothermal vents and methane seeps, with description of two new species.

The bathyal serpulid Laminatubus alvini ten Hove Zibrowius, 1986 was described from the periphery of hydrothermal vents of the Galapagos Rift and has been recorded from other vent communities of the East Pacific Rise (EPR). Here we assessed the biodiversity of serpulids collected from eastern Pacific hydrothermal vents and methane seeps using DNA sequences and morphology. Laminatubus alvini showed little genetic variation over a wide geographic range from the Alarcon Rise vents in southern Gulf of California (~23°N), to at least a point at 38°S on the EPR. Specimens from several methane seeps off Costa Rica and the Gulf of California (Mexico) differed markedly from those of Laminatubus alvini on DNA sequence data and in having seven thoracic chaetigers and lacking Spirobranchus-type special collar chaetae, thus fitting the diagnosis of Neovermilia. However, phylogenetic analysis of molecular data showed that L. alvini and the seep specimens form a well-supported clade. Moreover, among the seep specimens there was minimally a ~7% distance in mitochondrial cytochrome b sequences between a shallow-water (1000 m) seep clade restricted to Costa Rica and a deep-water clade (1800 m) from Costa Rica to Gulf of California. We describe the seep taxa here as morphologically indistinguishable L. paulbrooksi n. sp. and L. joycebrooksae n. sp.

Mitochondrial genome of Sabella spallanzanii (Gmelin, 1791) (Sabellida: Sabellidae).

We report the mitochondrial genome of Sabella spallanzanii, an invasive Mediterranean sabellid introduced to Australia and New Zealand. The mitogenome is 15,581 bp long and consists of 38 genes, including 13 protein coding genes, two rRNA genes, and 23 tRNA genes. It shows deviations from the putative annelid ground pattern, such as gene order re-arrangements and regions encoding on the negative strand. It is, however, very different from the mitogenome of the closely related serpulid, Spirobranchus giganteus. Phylogenetic analyses of the mitochondrial genes support a sister relationship of Sabella spallanzanii and Spirobranchus giganteus.

Alcohol stress on cyanobacterial membranes: New insights revealed by transcriptomics.

Cyanobacteria are model photosynthetic prokaryotic organisms often used in biotechnology to produce biofuels including alcohols. The effect of alcohols on cyanobacterial cell physiology and specifically on membrane fluidity is poorly understood. Previous research on various primary aliphatic alcohols found that alcohols with a short hydrocarbon chain (C1-C3) do not affect expression of genes related to membrane physical state. In addition, less water-soluble alcohols with a hydrocarbon chain longer than C8 are found to have a reduced ability to reach cellular membranes hence do not drastically change membrane physical state or induce expression of stress-responsive genes. Therefore, hexan-1-ol (C6) is suggested to have the most profound effect on cyanobacterial membrane physical state. Here, we studied the effects of hexan-1-ol on the cyanobacterium Synechocystis sp. PCC 6803 transcriptome. The transcriptome data obtained is compared to the previously reported analysis of gene expression induced by benzyl alcohol and butan-1-ol. The set of genes whose expression is induced after exposure to all three studied alcohols is identified. The expression under alcohol stress for several general stress response operons is analyzed, and examples of antisense interactions of RNA are investigated.