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561.
Vassilis Tsafas Evangelia Gavgiotaki Maria Tzardi Effrosyni Tsafa Costas Fotakis Irene Athanassakis George Filippidis 《Journal of biophotonics》2020,13(10)
Nonlinear optical imaging techniques have been widely used to reveal biological structures for accurate diagnosis at the cellular as well as the tissue level. In the present study, polarization‐dependent second‐harmonic generation (PSHG) was used to determine collagen orientation in breast cancer biopsy tissues (grades 0, I, II and III). The obtained data were processed using fast Fourier transform (FFT) analysis, while second‐harmonic generation (SHG) anisotropy and the “ratio parameter” values were also calculated. Such measurements were shown to be able to distinguish collagen structure modifications in different cancer grades tested. The analysis presented herein suggests that PSHG imaging could provide a quantitative evaluation of the tumor state and the distinction of malignant from benign breast tissues. The obtained results also allowed the development of a biophysical model, which can explain the aforementioned differentiations and is in agreement with the simulations relating the SHG anisotropy values with the mechanical tension applied to the collagen during cancer progression. The current approach could be a step forward for the development of new, nondestructive, label free optical diagnostic tools for cancer reducing the need of recalls and unnecessary biopsies, while potentially improving cancer detection rates. 相似文献
562.
Vassilis Tsafas Konstantina Giouroukou Konstantinos Kounakis Meropi Mari Costas Fotakis Nektarios Tavernarakis George Filippidis 《Journal of biophotonics》2021,14(12):e202100173
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. 相似文献
563.
564.
Jinheung Kim Yan Zang Miquel Costas Roger G. Harrison Elizabeth C. Wilkinson Lawrence Que Jr 《Journal of biological inorganic chemistry》2001,6(3):275-284
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. 相似文献
565.
Costas Perdikaris Anna Ergolavou Evangelia Gouva Cosmas Nathanailides Athanasios Chantzaropoulos Ioannis Paschos 《Reviews in Fish Biology and Fisheries》2012,22(1):17-27
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. 相似文献
566.
Odete D. Cordeiro Tomé S. Silva Ricardo N. Alves Benjamin Costas Tune Wulff Nadège Richard Mahaut de Vareilles Luís E. C. Concei??o Pedro M. Rodrigues 《Marine biotechnology (New York, N.Y.)》2012,14(6):714-729
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. 相似文献
567.
Costas G. Biliaderis 《Phytochemistry》1982,21(1):37-39
Changes in the physical and chemical properties of pea starch in developing seeds have been investigated. Increase in the iodine-binding capacity of st 相似文献
568.
Costas Tsioptsias Chrysoula Michailof George Stauropoulos Costas Panayiotou 《Carbohydrate polymers》2009,76(4):535-540
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. 相似文献
569.
Victoria López-Rodas Eduardo Costas Emilia Maneiro Fernando Marvá Mónica Rouco Antonio Delgado Antonio Flores-Moya 《Phycological Research》2009,57(2):111-117
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. 相似文献