Monitoring aging-associated structural alterations in Caenorhabditis elegans striated muscles via polarization-dependent second-harmonic generation measurements

The in-vivo elucidation of the molecular mechanisms underlying muscles dysfunction due to aging via non-invasive label free imaging techniques is an important issue with high biological significance. In this study, polarization-dependent second-harmonic generation (PSHG) was used to evaluate structural alterations in the striated muscles during Caenorhabditis elegans lifespan. Young and old wild-type animals were irradiated. The obtained results showed that it was not feasible to detect differences in the structure of myosin that could be correlated with the aging of the worms, via the implementation of the classical, widely used, cylindrical symmetry model and the calculation of the SHG anisotropy values. A trigonal symmetry model improved the extracted results; however, the best outcome was originated from the application of a general model. Myosin structural modifications were monitored via the estimation of the difference in spectral phases derived from discrete Fourier transform analysis. Age classification of the nematodes was achieved by employing both models, proving the usefulness of the usage of PSHG microscopy as a potential diagnostic tool for the investigation of muscle diseases.     

Asparagine couples mitochondrial respiration to ATF4 activity and tumor growth

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A nonheme iron(II) complex that models the redox cycle of lipoxygenase

The air-stable complex [Fe(6-Me3-TPA) (O2CAr)]+ [1; 6-Me3-TPA = tris(6-methyl-2-pyridylmethyl)amine] has been synthesized as a model for the iron(II) site of lipoxygenase. This iron(II) complex reacts with 0.5 equiv ROOH to form a yellow species, which has been formulated as [FeIII(OH)(6-Me3-TPA) (O2CAr)]+ (2) by electrospray mass spectrometry. Addition of more ROOH converts 2 into a purple species, which is characterized by electrospray ionization mass spectrometry and resonance Raman spectroscopy as [FeIII(OOR)(6-Me3-TPA)(O2CAr)]+. The purple species is metastable and decomposes via Fe-O bond homolysis to regenerate the starting iron(II) complex. These metal-centered transformations parallel the changes observed for lipoxygenase in its reaction with its product hydroperoxide.     

Carassius gibelio in Greece: the dominant naturalised invader of freshwaters

Ichthyofauna in the Hellenic freshwaters is quite diverse consisted of 161 species (including 28 non-natives), out of the 546 native species in Pan-European level. However, the status of many aquatic ecosystems is currently degraded as a result of a variety of anthropogenic impacts. This has direct reflection on the conservation status of the indigenous and native fish species whose populations are in many cases declining in favor of the invasive ones. Prussian carp (Carassius gibelio) is probably the most dominant invasive species and currently is considered as naturalized in about 26 lake and river basins. Its successful adaptation and proliferation is mainly attributed to its dual reproductive mode (allogynogenetic and gonochoristic), the opportunistic-omnivorous feeding habits and the ability to withstand and flourish in adverse ecological conditions. Accordingly, it exerts competitive, as well as destructive effects upon the indigenous fish species (sperm parasitism, antagonism for food, spawning grounds and spawning substrates) and therefore, efforts are needed to sustain a relative balance of the populations. This review aims to critically discuss the status of C. gibelio in Greece, the intrinsic causes of establishment and the observed impacts on ecosystems. Finally, reasonable actions are proposed related to exploitation of C. gibelio stocks and a path model for the protection of native fish species and their ecosystems.     

Changes in Liver Proteome Expression of Senegalese Sole (Solea senegalensis) in Response to Repeated Handling Stress

The Senegalese sole, a high-value flatfish, is a good candidate for aquaculture production. Nevertheless, there are still issues regarding this species’ sensitivity to stress in captivity. We aimed to characterize the hepatic proteome expression for this species in response to repeated handling and identify potential molecular markers that indicate a physiological response to chronic stress. Two groups of fish were reared in duplicate for 28?days, one of them weekly exposed to handling stress (including hypoxia) for 3?min, and the other left undisturbed. Two-dimensional electrophoresis enabled the detection of 287 spots significantly affected by repeated handling stress (Wilcoxon–Mann–Whitney U test, p?<?0.05), 33 of which could be reliably identified by peptide mass spectrometry. Chronic exposure to stress seems to have affected protein synthesis, folding and turnover (40S ribosomal protein S12, cathepsin B, disulfide-isomerase A3 precursor, cell-division cycle 48, and five distinct heat shock proteins), amino acid metabolism, urea cycle and methylation/folate pathways (methionine adenosyltransferase I α, phenylalanine hydroxylase, mitochondrial agmatinase, serine hydroxymethyltransferase, 3-hydroxyanthranilate 3,4-dioxygenase, and betaine homocysteine methyltransferase), cytoskeletal (40S ribosomal protein SA, α-actin, β-actin, α-tubulin, and cytokeratin K18), aldehyde detoxification (aldehyde dehydrogenase 4A1 family and aldehyde dehydrogenase 7A1 family), carbohydrate metabolism and energy homeostasis (fatty acid-binding protein, enolase 3, enolase 1, phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase, aconitase 1, mitochondrial ATP synthase α-subunit, and electron-transfer flavoprotein α polypeptide), iron and selenium homeostasis (transferrin and selenium binding protein 1), steroid hormone metabolism (3-oxo-5-β-steroid 4-dehydrogenase), and purine salvage (hypoxanthine phosphoribosyltransferase). Further characterization is required to fully assess the potential of these markers for the monitoring of fish stress response to chronic stressors of aquaculture environment.     

Characteristics of starch in developing pea seeds

Changes in the physical and chemical properties of pea starch in developing seeds have been investigated. Increase in the iodine-binding capacity of st     

Chitin and carbon aerogels from chitin alcogels

Supercritical point drying of gels is a common technique for the production of a specific category of nano-porous materials called aerogels. We have successfully prepared chitin aerogels by extracting the solvent from the alcogels (gels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. The produced nano-porous materials exhibit the typical properties of aerogels such as high porosity, high surface area, and low density, which make them quite attractive for many applications. The use of chitin, however, is of particular interest for the production of aerogels not only for being abundant and cheap but also because it has important inherent properties such as biocompatibility, non toxicity, thermal and chemical stability. In this work we examine the influence of different parameters on the porosity characteristics of the aerogels, such as the drying conditions (temperature and pressure), the nature of the solvent, and the gel concentration. Since these aerogels collapse in liquid medium, we also investigated the possibility of their utilization as carbon aerogel precursors.     

Living in Vulcan's forge: Algal adaptation to stressful geothermal ponds on Vulcano Island (southern Italy) as a result of pre-selective mutations

Four species of eukaryotic algae proliferate in the sulfureous, acidic (pH 3.1) water of the largest geothermal pond on Vulcano Island (southern Italy). Consequently, this pond constitutes a natural laboratory for analysis of adaptation by phytoplankters to extremely stressful conditions. To distinguish between the pre-selective or post-selective origin of adaptation processes allowing the existence of phytoplankters in the pond, a Luria-Delbrück fluctuation test was carried out with the chlorophycean Dictyosphaerium chlorelloides and the cyanobacterium Microcystis aeruginosa , both isolated from non-extreme waters; natural water from the Vulcano Island pond was used as selective factor. Preselective, resistant D. chlorelloides cells appeared with a frequency of 4.7 × 10⁻⁷ per cell per generation. We propose that the micro-algae inhabiting this stressful pond could be the descendents of chance mutants that arrived in the past or are even arriving at the present. The genetic adaptation of D. chlorelloides to Vulcano waters could help to explain the survival of photosynthesizers in very stressful geothermal waters during the Neoproterozoic 'snowball Earth', a period when primary production collapsed in the biosphere. On the other hand, adaptation to these conditions was not observed in M. aeruginosa , suggesting that cyanobacteria may not be able to develop any kind of adaptation to Vulcano pond water.