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     

Organotin meclofenamic complexes: Synthesis, crystal structures and antiproliferative activity of the first complexes of meclofenamic acid - Novel anti-tuberculosis agents

The complexes [Me₂(Meclo)SnOSn(Meclo)Me₂]₂ (2) and [Ph₃Sn(Meclo)] (3) where HMeclo is meclofenamic acid, N-(2,6-dichloro-m-tolylanthranilic acid)], have been prepared and structurally characterized by means of vibrational, ¹H and ¹³C NMR spectroscopies. The crystal structure of complexes (2) and (3) have been determined by X-ray crystallography. Three distannoxane rings are present to the dimeric tetraorganodistannoxane of planar ladder arrangement of (2). The structure is centro symmetric and features a central rhombus Sn₂O₂ unit two additional tin atoms linked at the oxygen atoms. Five- and six-coordinated tin centers are present in the dimer distannoxane. X-ray analysis of (3) revealed a penta-coordinated structure containing Ph₃Sn coordinated to the chelated carboxylato group. The polar imino hydrogen atom participates in intra-molecular hydrogen bonds. Complexes (2) and (3) are self-assembled via π → π, C-H-π, stacking interactions and intra-molecular hydrogen bonds. Meclofenamic acid and [Ph₃Sn(Meclo)] have been evaluated for antiproliferative activity in vitro against three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). The [Ph₃Sn(Meclo)] complex exhibited high cytotoxic activity against all the cancer cell lines. Meclofenamic and [Ph₃Sn(Meclo)] were tested for anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv. The [Ph₃Sn(Meclo)] complex was found to be a promising anti-mycobacterial lead compound, displaying high activity against M. tuberculosis H37Rv.     

Cloning and characterization of the trout perforin

The pore-forming protein, perforin is one of the effectors of cell-mediated killing. A perforin cDNA clone was isolated from rainbow trout (Oncorhynchus mykiss) after screening of a spleen cDNA library. The full-length cDNA is 2070 bp in size, encoding for a polypeptide of 589 amino acids. The predicted amino acid sequence of the trout perforin is 64, 58 and 40% identical to those of Japanese flounder, zebrafish and human perforins, respectively. Although its membrane attack complex/perforin (MACPF) domain is conserved, trout perforin shows low homology to human and trout terminal complement components (C6, C7, C8 and C9), ranging from 19 to 26% identity. Expression analysis reveals that the trout perforin gene is expressed in the blood, brain, heart, kidney, intestine and spleen. Phylogenetic analysis of proteins which belong to the MACPF superfamily clusters the trout perforin in the same group with other known perforins.     

High-throughput screening of ecdysone agonists using a reporter gene assay followed by 3-D QSAR analysis of the molting hormonal activity

In this study, 172 diacylhydrazine analogs were examined for their ability to activate an ecdysone (molting hormone)-dependent reporter gene in a silkworm (Bombyx mori) cell-based high-throughput screening assay. The measured EC(50) values (concentration required to cause an effect in 50% of the cells) were used to construct a 3-D QSAR model that describes the ecdysone agonist activities of the diacylhydrazine analogs. Of these compounds, 14 exhibited no activity and were excluded from the 3-D QSAR analysis. The resulting equation described approximately 74% of the activity for 158 compounds. The final equation consisted of 42% electrostatic and 58% steric effects (r(2) = 0.74 and q(2) = 0.45). Comparative molecular field analysis (CoMFA) was used to visualize the steric and electrostatic potential fields that were favorable and unfavorable for biological activity. Of particular interest was the observation that the hydrophobic parameter (logP) was not necessary for describing the observed activities, although previous studies have cited the importance of hydrophobic parameters in both classical and 3-D QSAR analyses of these compounds. Modeling studies of the B. mori ecdysone receptor supported the observed physicochemical parameters required for activity reported by the CoMFA models. Comparison of the present analysis with those performed using other lepidopteran assay systems evidenced a high degree of correlation (r(2) = 0.81 for a Sf-9 cell-based assay and r(2) = 0.89 for a Chilo suppressalis integument-based assay), indicating that it is valid to compare the results generated with the B. mori cell-based system to those generated with previous lepidopteran assays. This novel assay system is amendable to a high-throughput screening format and should greatly increase our ability to discover novel agonists of molting hormone (ecdysone) activity.     

Complex regulation of the TRPM8 cold receptor channel: role of arachidonic acid release following M3 muscarinic receptor stimulation

Cold/menthol-activated TRPM8 (transient receptor potential channel melastatin member 8) is primarily expressed in sensory neurons, where it constitutes the principal receptor of environmental innocuous cold. TRPM8 has been shown to be regulated by multiple influences such as phosphorylation, pH, Ca(2+), and lipid messengers. One such messenger is arachidonic acid (AA), which has been shown to inhibit TRPM8 channel activity. However, the physiological pathways mediating the inhibitory effect of AA on TRPM8 still remain unknown. Here, we demonstrate that TRPM8 is regulated via M3 muscarinic acetylcholine receptor-coupled signaling cascade based on the activation of cytosolic phospholipase A2 (cPLA2) and cPLA2-catalyzed derivation of AA. Stimulation of M3 receptors heterologously co-expressed with TRPM8 in HEK-293 cells by nonselective muscarinic agonist, oxotremorine methiodide (Oxo-M), caused inhibition of TRPM8-mediated membrane current, which could be mimicked by AA and antagonized by pharmacological or siRNA-mediated cPLA2 silencing. Our results demonstrate the intracellular functional link between M3 receptor and TRPM8 channel via cPLA2/AA and suggest a novel physiological mechanism of arachidonate-mediated regulation of TRPM8 channel activity through muscarinic receptors. We also summarize the existing TRPM8 regulations and discuss their physiological and pathological significance.     

Netrin-1 signaling dampens inflammatory peritonitis

Previous studies implicated the anti-inflammatory potential of the adenosine 2B receptor (A2BAR). A2BAR activation is achieved through adenosine, but this is limited by its very short t(1/2). To further define alternative adenosine signaling, we examined the role of netrin-1 during acute inflammatory peritonitis. In this article, we report that animals with endogenous repression of netrin-1 (Ntn1(+/-)) demonstrated increased cell count, increased peritoneal cytokine concentration, and pronounced histological changes compared with controls in a model of zymosan A peritonitis. Exogenous netrin-1 significantly decreased i.p. inflammatory changes. This effect was not present in animals with deletion of A2BAR (A2BAR(-/-)). A2BAR(-/-) animals demonstrated no change in cell count, i.p. cytokine concentration, or histology in response to netrin-1 injection. These data strengthen the role of netrin-1 as an immunomodulatory protein exerting its function in dependence of the A2BAR and further define alternative adenosine receptor signaling.     

Microalgal lipids biochemistry and biotechnological perspectives

In the last few years, there has been an intense interest in using microalgal lipids in food, chemical and pharmaceutical industries and cosmetology, while a noteworthy research has been performed focusing on all aspects of microalgal lipid production. This includes basic research on the pathways of solar energy conversion and on lipid biosynthesis and catabolism, and applied research dealing with the various biological and technical bottlenecks of the lipid production process. In here, we review the current knowledge in microalgal lipids with respect to their metabolism and various biotechnological applications, and we discuss potential future perspectives.     

Boron bridging of rhamnogalacturonan‐II,monitored by gel electrophoresis,occurs during polysaccharide synthesis and secretion but not post‐secretion

The cell‐wall pectic domain rhamnogalacturonan‐II (RG‐II) is cross‐linked via borate diester bridges, which influence the expansion, thickness and porosity of the wall. Previously, little was known about the mechanism or subcellular site of this cross‐linking. Using polyacrylamide gel electrophoresis (PAGE) to separate monomeric from dimeric (boron‐bridged) RG‐II, we confirmed that Pb²⁺ promotes H₃BO₃‐dependent dimerisation in vitro. H₃BO₃ concentrations as high as 50 mm did not prevent cross‐linking. For in‐vivo experiments, we successfully cultured ‘Paul's Scarlet’ rose (Rosa sp.) cells in boron‐free medium: their wall‐bound pectin contained monomeric RG‐II domains but no detectable dimers. Thus pectins containing RG‐II domains can be held in the wall other than via boron bridges. Re‐addition of H₃BO₃ to 3.3 μm triggered a gradual appearance of RG‐II dimer over 24 h but without detectable loss of existing monomers, suggesting that only newly synthesised RG‐II was amenable to boron bridging. In agreement with this, Rosa cultures whose polysaccharide biosynthetic machinery had been compromised (by carbon starvation, respiratory inhibitors, anaerobiosis, freezing or boiling) lost the ability to generate RG‐II dimers. We conclude that RG‐II normally becomes boron‐bridged during synthesis or secretion but not post‐secretion. Supporting this conclusion, exogenous [³H]RG‐II was neither dimerised in the medium nor cross‐linked to existing wall‐associated RG‐II domains when added to Rosa cultures. In conclusion, in cultured Rosa cells RG‐II domains have a brief window of opportunity for boron‐bridging intraprotoplasmically or during secretion, but secretion into the apoplast is a point of no return beyond which additional boron‐bridging does not readily occur.     

Drosophila oogenesis as a bio-marker responding to EMF sources

The model biological organisms Drosophila melanogaster and Drosophila virilis have been utilized to assess effects on apoptotic cell death of follicles during oogenesis and reproductive capacity (fecundity) decline. A total of 280 different experiments were performed using newly emerged flies exposed for short time daily for 3–7?d to various EMF sources including: GSM 900/1800?MHz mobile phone, 1880–1900?MHz DECT wireless base, DECT wireless handset, mobile phone-DECT handset combination, 2.44?GHz wireless network (Wi-Fi), 2.44?GHz blue tooth, 92.8?MHz FM generator, 27.15?MHz baby monitor, 900?MHz CW RF generator and microwave oven’s 2.44?GHz RF and magnetic field components. Mobile phone was used as a reference exposure system for evaluating factors considered very important in dosimetry extending our published work with D. melanogaster to the insect D. virilis. Distance from the emitting source, the exposure duration and the repeatability were examined. All EMF sources used created statistically significant effects regarding fecundity and cell death-apoptosis induction, even at very low intensity levels (0.3?V/m blue tooth radiation), well below ICNIRP’s guidelines, suggesting that Drosophila oogenesis system is suitable to be used as a biomarker for exploring potential EMF bioactivity. Also, there is no linear cumulative effect when increasing the duration of exposure or using one EMF source after the other (i.e. mobile phone and DECT handset) at the specific conditions used. The role of the average versus the peak E-field values as measured by spectrum analyzers on the final effects is discussed.