Microbial community differentiation between active and inactive sulfide chimneys of the Kolumbo submarine volcano,Hellenic Volcanic Arc

Over the last decades, there has been growing interest about the ecological role of hydrothermal sulfide chimneys, their microbial diversity and associated biotechnological potential. Here, we performed dual-index Illumina sequencing of bacterial and archaeal communities on active and inactive sulfide chimneys collected from the Kolumbo hydrothermal field, situated on a geodynamic convergent setting. A total of 15,701 OTUs (operational taxonomic units) were assigned to 56 bacterial and 3 archaeal phyla, 133 bacterial and 16 archaeal classes. Active chimney communities were dominated by OTUs related to thermophilic members of Epsilonproteobacteria, Aquificae and Deltaproteobacteria. Inactive chimney communities were dominated by an OTU closely related to the archaeon Nitrosopumilus sp., and by members of Gammaproteobacteria, Deltaproteobacteria, Planctomycetes and Bacteroidetes. These lineages are closely related to phylotypes typically involved in iron, sulfur, nitrogen, hydrogen and methane cycling. Overall, the inactive sulfide chimneys presented highly diverse and uniform microbial communities, in contrast to the active chimney communities, which were dominated by chemolithoautotrophic and thermophilic lineages. This study represents one of the most comprehensive investigations of microbial diversity in submarine chimneys and elucidates how the dissipation of hydrothermal activity affects the structure of microbial consortia in these extreme ecological niches.

     

Effects of Collagen IV on Neuroblastoma Cell Matrix-Related Functions

Integrin-mediated interactions with collagen IV and its domains were examined in a human neuroblastoma cell line (SK-N-SH). By adhesion assays we demonstrated that neuroblastoma cells bound to solid-phase intact collagen IV and synthetic cell-binding peptide HEP-III, derived from the collagenous part of the molecule, but not to the main noncollagenous NC1 domain or to the synthetic cell-binding peptide HEP-I, derived from this domain. Monoclonal antibodies against β1, α3, and αvβ3 integrins resulted in inhibition of cell binding to collagenous substrates by 95, 30, and 35%, respectively. By flow cytometry and immunoblotting it was shown that culture of SK-N-SH cells on collagen IV resulted in alteration in the expression of major neuroblastoma cell integrins. Binding to collagen IV induced the expression and activation of matrix metalloproteinases A and B (MMP-2, MMP-9), with a concomitant increase at the protein level of tissue-specific inhibitors of metalloproteinases (TIMP-1, TIMP-2). Finally, the expression of MMP-2 was significantly up-regulated by anti-α3β1 antibodies, whereas ligation of anti-αvβ3 antibodies resulted in a modest down-regulation of MMP-2. Our results indicate that the presence of collagen IV modulates the expression of integrins, which are used for binding to this glycoprotein, and MMP-2 secreted by SK-N-SH cells.     

Extraocular muscle in merosin-deficient muscular dystrophy: cation homeostasis is maintained but is not mechanistic in muscle sparing

Extraocular muscle is uniquely spared from damage in merosin-deficient congenital muscular dystrophy. Using a murine model, we have tested the hypothesis that the maintenance of calcium homeostasis is mechanistic in extraocular muscle protection. Atomic absorption spectroscopy has demonstrated a strong correlation between the perturbation of calcium homeostasis in hindlimb muscle that is severely damaged and the absence of changes in calcium in extraocular muscle. If, as in other skeletal muscles, extraocular muscle fibers are destabilized by merosin deficiency, we would expect an increase in total muscle calcium coupled with an adaptive response in the high capacity/speed of the sarcoplasmic reticulum of the eye muscle. However, we have not observed the expected increases in total muscle calcium content, Ca²⁺-ATPase activity, Na⁺/Ca²⁺ exchanger content, or smooth ER Ca²⁺-ATPase content that are predicted by this model. Instead, these results indicate that the increased membrane permeability that characterizes, and is potentially mechanistic in, myofiber degeneration in muscular dystrophy does not occur in merosin-deficient extraocular muscle. Thus, the high-capacity calcium-scavenging systems are not primarily responsible for extraocular muscle protection in muscular dystrophy.     

Adenosine A2A receptors are required for glutamate mGluR5‐ and dopamine D1 receptor‐evoked ERK1/2 phosphorylation in rat hippocampus: involvement of NMDA receptor

Interaction between mGluR5 and NMDA receptors (NMDAR ) is vital for synaptic plasticity and cognition. We recently demonstrated that stimulation of mGluR5 enhances NMDAR responses in hippocampus by phosphorylating NR2B(Tyr1472) subunit, and this reaction was enabled by adenosine A_2A receptors (A_2AR) (J Neurochem, 135, 2015, 714). In this study, by using in vitro phosphorylation and western blot analysis in hippocampal slices of male Wistar rats, we show that mGluR5 stimulation or mGluR5/NMDAR s co‐stimulation synergistically activate ERK 1/2 signaling leading to c‐Fos expression. Interestingly, both reactions are under the permissive control of endogenous adenosine acting through A_2ARs. Moreover, mGluR5‐mediated ERK 1/2 phosphorylation depends on NMDAR , which however exhibits a metabotropic way of function, since no ion influx through its ion channel is required. Furthermore, our results demonstrate that mGluR5 and mGluR5/NMDAR ‐evoked ERK 1/2 activation correlates well with the mGluR5/NMDAR ‐evoked NR2B(Tyr1472) phosphorylation, since both phenomena coincide temporally, are Src dependent, and are both enabled by A_2ARs. This indicates a functional involvement of NR2B(Tyr1472) phosphorylation in the ERK 1/2 activation. Our biochemical results are supported by electrophysiological data showing that in CA 1 region of hippocampus, the theta burst stimulation (TBS)‐induced long‐term potentiation coincides temporally with an increase in ERK 1/2 activation and both phenomena are dependent on the tripartite A_2A, mGlu5, and NMDAR s. Furthermore, we show that the dopamine D1 receptors evoked ERK 1/2 activation as well as the NR2B(Tyr1472) phosphorylation are also regulated by endogenous adenosine and A_2ARs. In conclusion, our results highlight the A_2ARs as a crucial regulator not only for NMDAR responses, but also for regulating ERK 1/2 signaling and its downstream pathways, leading to gene expression, synaptic plasticity, and memory consolidation.

     

Mapping abundance distribution of small pelagic species applying hydroacoustics and Co-Kriging techniques

Hydroacoustic technology provides ground tools for the estimation of abundance and spatial distribution of pelagic species. The final products of such surveys, the interpolated choropleth maps, are based on a Geostatistical analysis of the acoustic measurements to minimise, as much as possible, the interpolation error, and to quantify uncertainty. The current study is based on fisheries acoustic measurements and satellite images covering the sea area of Thermaikos Gulf over the years 1996, 1997 and 1998. Spatial interpolations describing the abundance and distribution of small pelagic species in the research area, as well as sea surface temperature (SST), Chlorophyll-a content (SSC) and average depth, were produced, based on Ordinary and Universal Kriging and Co-Kriging Geostatistical methods. The results of the Geostatistical analysis showed that the Co-Kriging spatial interpolation method produced the best results regarding fish abundance when SST and average depth variables were included in the model. The latter indicates that there is an existing spatial cross-correlation between fish abundance and the environmental variables. Consequently, the potential reduction of the overall error in the estimation process, as presented in this study, is very significant, particularly with regard to error reduction in stock assessment and management. Guest editor: V. D. Valavanis Essential Fish Habitat Mapping in the Mediterranean     

The primary folding defect and rescue of ΔF508 CFTR emerge during translation of the mutant domain

In the vast majority of cystic fibrosis (CF) patients, deletion of residue F508 from CFTR is the cause of disease. F508 resides in the first nucleotide binding domain (NBD1) and its absence leads to CFTR misfolding and degradation. We show here that the primary folding defect arises during synthesis, as soon as NBD1 is translated. Introduction of either the I539T or G550E suppressor mutation in NBD1 partially rescues ΔF508 CFTR to the cell surface, but only I539T repaired ΔF508 NBD1. We demonstrated rescue of folding and stability of NBD1 from full-length ΔF508 CFTR expressed in cells to isolated purified domain. The co-translational rescue of ΔF508 NBD1 misfolding in CFTR by I539T advocates this domain as the most important drug target for cystic fibrosis.     

Carbon dioxide balneotherapy and cardiovascular disease

Carbon dioxide (CO(2)) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO(2) baths in various cardiovascular diseases. The three main effects of CO(2) hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO(2) baths in other cardiovascular substrates is discussed.     

Synthesis of variously coupled conjugates of D-glucose, 1,3,4-oxadiazole, and 1,2,3-triazole for inhibition of glycogen phosphorylase

5-(O-Perbenzoylated-β-D-glucopyranosyl)tetrazole was obtained from O-perbenzoylated-β-D-glucopyranosyl cyanide by Bu(3)SnN(3) or Me(3)SiN(3)-Bu(2)SnO. This tetrazole was transformed into 5-ethynyl- as well as 5-chloromethyl-2-(O-perbenzoylated-β-D-glucopyranosyl)-1,3,4-oxadiazoles by acylation with propiolic acid-DCC or chloroacetyl chloride, respectively. The chloromethyl oxadiazole gave the corresponding azidomethyl derivative on treatment with NaN(3). These compounds were reacted with several alkynes and azides under Cu(I) catalysed cycloaddition conditions to give, after removal of the protecting groups by the Zemplén protocol, β-D-glucopyranosyl-1,3,4-oxadiazolyl-1,2,3-triazole, β-D-glucopyranosyl-1,2,3-triazolyl-1,3,4-oxadiazole, and β-D-glucopyranosyl-1,3,4-oxadiazolylmethyl-1,2,3-triazole type compounds. 5-Phenyltetrazole was also transformed under the above conditions into a series of aryl-1,3,4-oxadiazolyl-1,2,3-triazoles, aryl-1,2,3-triazolyl-1,3,4-oxadiazoles, and aryl-1,3,4-oxadiazolylmethyl-1,2,3-triazoles. The new compounds were assayed against rabbit muscle glycogen phosphorylase b and the best inhibitors had inhibition constants in the upper micromolar range (2-phenyl-5-[1-(β-D-glucopyranosyl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 36: K(i)=854μM, 2-(β-D-glucopyranosyl)-5-[1-(naphthalen-2-yl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 47: K(i)=745μM).     

Phenolic Acid Composition,Antiatherogenic and Anticancer Potential of Honeys Derived from Various Regions in Greece

The phenolic acid profile of honey depends greatly on its botanical and geographical origin. In this study, we carried out a quantitative analysis of phenolic acids in the ethyl acetate extract of 12 honeys collected from various regions in Greece. Our findings indicate that protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid and p-coumaric acid are the major phenolic acids of the honeys examined. Conifer tree honey (from pine and fir) contained significantly higher concentrations of protocatechuic and caffeic acid (mean: 6640 and 397 µg/kg honey respectively) than thyme and citrus honey (mean of protocatechuic and caffeic acid: 437.6 and 116 µg/kg honey respectively). p-Hydroxybenzoic acid was the dominant compound in thyme honeys (mean: 1252.5 µg/kg honey). We further examined the antioxidant potential (ORAC assay) of the extracts, their ability to influence viability of prostate cancer (PC-3) and breast cancer (MCF-7) cells as well as their lowering effect on TNF- α-induced adhesion molecule expression in endothelial cells (HAEC). ORAC values of Greek honeys ranged from 415 to 2129 µmol Trolox equivalent/kg honey and correlated significantly with their content in protocatechuic acid (p<0.001), p-hydroxybenzoic acid (p<0.01), vanillic acid (p<0.05), caffeic acid (p<0.01), p-coumaric acid (p<0.001) and their total phenolic content (p<0.001). Honey extracts reduced significantly the viability of PC-3 and MCF-7 cells as well as the expression of adhesion molecules in HAEC. Importantly, vanillic acid content correlated significantly with anticancer activity in PC-3 and MCF-7 cells (p<0.01, p<0.05 respectively). Protocatechuic acid, vanillic acid and total phenolic content correlated significantly with the inhibition of VCAM-1 expression (p<0.05, p<0.05 and p<0.01 respectively). In conclusion, Greek honeys are rich in phenolic acids, in particular protocatechuic and p-hydroxybenzoic acid and exhibit significant antioxidant, anticancer and antiatherogenic activities which may be attributed, at least in part, to their phenolic acid content.