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1.
Three major glycan fractions of 580 kDa (g580), 150 kDa (g150), and 2 kDa (g2) were isolated and purified from Lytechinus pictus sea urchin embryos at the mesenchyme blastula stage by gel filtration and high pressure liquid chromatography. Chemical analysis, by gas chromatography, revealed that g580 is highly sulfated and rich in N-acetylglucosamine, N-acetylgalactosamine, glucuronic acid, and fucose. The g150 fraction is less acidic than g580 and contains high amounts of amino sugars, xylose, and mannose. The g2 fraction is neutral, rich in N-acetylglucosamine, mannose, and galactose. The g580 and g150 fractions are resistant to glycosaminoglycan-degrading enzymes, indicating that they are distinct from the glycosaminoglycans. The g580 fraction resembles, with respect to chemical composition, a previously characterized 200 kDa sponge adhesion glycan (g200). The binding of the monoclonal antibody Block 2, which recognizes a repetitive epitope on g200, as well as of the anti-g580 polyclonal antibodies to both g580 and g200 indicated that these two glycans share similar antigenic determinants. The Fab fragments of the Block 2 antibody, which previously have been shown to inhibit cell adhesion in sponges, also blocked the reaggregation of dissociated sea urchin mesenchyme blastula cells. These results indicate that g580 carries a carbohydrate epitope, similar to the sponge adhesion epitope of g200, which is involved in sea urchin embryonal cell adhesion. 相似文献
2.
Mandilara GD Smeti EM Mavridou AT Lambiri MP Vatopoulos AC Rigas FP 《FEMS microbiology letters》2006,263(1):119-126
The use of bacteriophages as potential indicators of faecal pollution has recently been studied. The correlation of the number of bacterial indicators and the presence of three groups of bacteriophages, namely somatic coliphages (SOMCPH), F-RNA-specific phages (FRNAPH) and phages of Bacteroides fragilis (BFRPH), in raw and treated wastewater and sludge is presented in this study. Raw and treated wastewater and sewage sludge samples from two wastewater treatment plants in Athens were collected on a monthly basis, over a 2-year period, and analysed for total coliforms, Escherichia coli, intestinal enterococci and the three groups of bacteriophages. A clear correlation between the number of bacterial indicators and the presence of bacteriophages was observed. SOMCPH may be used as additional indicators, because of their high densities and resistance to various treatment steps. 相似文献
3.
Harker N Garefalaki A Menzel U Ktistaki E Naito T Georgopoulos K Kioussis D 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(11):6368-6377
The CD8 gene is silent in CD4(-)CD8(-) double-negative thymocytes, expressed in CD4(+)CD8(+) double-positive cells, and silenced in cells committing to the CD4(+) single-positive (SP) lineage, remaining active in the CD8(+) SP lineage. In this study, we show that the chromatin of the CD8 locus is remodeled in C57BL/6 and B6/J Rag1(-/-) MOM double-negative thymocytes as indicated by DNaseI hypersensitivity and widespread bivalent chromatin marks. Pre-TCR signaling coincides with chromatin bivalency resolution into monovalent activating modifications in double-positive and CD8 SP cells. Shortly after commitment to CD4 SP cell lineage, monovalent repressive characteristics and chromatin inaccessibility are established. Differential binding of Ikaros, NuRD, and heterochromatin protein 1α on the locus during these processes may participate in the complex regulation of CD8. 相似文献
4.
Asprouli Eleni Kalafati Ioanna Panagiota Sakellari Aikaterini Karavoltsos Sotirios Vlachogiannakos John Revenas Konstantinos Kokkinos Alexander Dassenakis Manos Dedoussis George V. Kalogeropoulos Nick 《Biological trace element research》2019,188(2):326-333
Biological Trace Element Research - Nonalcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of metabolic syndrome. Its global prevalence is estimated between 25 and 45%,... 相似文献
5.
6.
Ectodermal organs such as teeth, hair follicles, and mammary glands begin their development as placodes. These are local epithelial thickenings that invaginate into mesenchymal space. There is currently little mechanistic understanding of the cellular processes driving the early morphogenesis of these organs and of why they lead to invagination rather than simple tissue thickening. Here, we show that placode invagination depends on horizontal contraction of superficial layers of cells that form a shrinking and thickening canopy over underlying epithelial cells. This contraction occurs by cell intercalation and is mechanically coupled to the basal layer by peripheral basal cells that extend apically and centripetally while remaining attached to the basal lamina. This process is topologically analogous to well-studied apical constriction mechanisms, but very different from them both in scale and molecular mechanism. Mechanical cell–cell coupling is propagated through the tissue via E-cadherin junctions, which in turn depend on tissue-wide tension. We further present evidence that this mechanism is conserved among different ectodermal organs and is, therefore, a novel and fundamental morphogenetic motif widespread in embryonic development. 相似文献
7.
Eleni A. Charmpila Maximilian Wagner Bettina Reichenbacher 《Journal of fish biology》2021,98(5):1450-1455
Otolith morphology is a widely accepted tool for species identification in teleost fish, but whether this holds true for very small species remains to be explored. Here, the saccular otoliths of the cryptobenthic Mediterranean clingfish Gouania (Gobiesocidae) are described for the first time. The new data, although preliminary, indicate that otolith morphology and morphometry support the recognition of the recently differentiated five species of Gouania in the Mediterranean Sea. Furthermore, otoliths of phylogenetically closely related Gouania species resemble each other more than do those of the more distantly related species. 相似文献
8.
Jan Richter Christakis Panayiotou Christina Tryfonos Dana Koptides Maria Koliou Nikolas Kalogirou Eleni Georgiou Christina Christodoulou 《PloS one》2016,11(1)
In order to improve clinical management and prevention of viral infections in hospitalised children improved etiological insight is needed. The aim of the present study was to assess the spectrum of respiratory viral pathogens in children admitted to hospital with acute respiratory tract infections in Cyprus. For this purpose nasopharyngeal swab samples from 424 children less than 12 years of age with acute respiratory tract infections were collected over three epidemic seasons and were analysed for the presence of the most common 15 respiratory viruses. A viral pathogen was identified in 86% of the samples, with multiple infections being observed in almost 20% of the samples. The most frequently detected viruses were RSV (30.4%) and Rhinovirus (27.4%). RSV exhibited a clear seasonality with marked peaks in January/February, while rhinovirus infections did not exhibit a pronounced seasonality being detected almost throughout the year. While RSV and PIV3 incidence decreased significantly with age, the opposite was observed for influenza A and B as well as adenovirus infections. The data presented expand our understanding of the epidemiology of viral respiratory tract infections in Cypriot children and will be helpful to the clinicians and researchers interested in the treatment and control of viral respiratory tract infections. 相似文献
9.
Ippokratis Messaritakis Vasiliki Christodoulou Apostolos Mazeris Eleni Koutala Antonia Vlahou Sevasti Papadogiorgaki Maria Antoniou 《PloS one》2013,8(6)
Resistance of pathogens to drugs is a growing concern regarding many diseases. Parasites like Leishmania, Plasmodium and Entamoeba histolytica; and neoplastic cells, present the multidrug-resistant phenotype rendering chemotherapy ineffective. The acquired resistance of Leishmania to antimony has generated intense research on the mechanisms involved but the question has not yet been resolved. To test the hypothesis that drug efflux in Leishmania, as measured by flow cytometry using the fluorescent dye Rhodamine-123, is largely dependent on the number of efflux pumps an isolate can express, the amount of Pgp 170 molecules was assessed in ten field isolates (5 “resistant” and 5 “susceptible”) using: Western Blotting, Confocal and Transmission Electron Microscopy, and proteomics. Their survival after exposure to three antileishmanial drugs, in vitro, was evaluated and clinical data were compared to the in vitro results. All isolates were resistant to Glucantime but susceptible to Miltefosine, whilst Amphotericin B was more effective on the “susceptible” isolates. The MDR gene, expressing the transmembrane efflux pump Pgp 170, appears to play a key role in the phenomenon of drug resistance. When “susceptible” versus “resistant” parasites were compared, it was shown that the higher the number of Pgp 170 molecules the higher the Rhodamine-123 efflux from the parasite body and, when exposed to the drug, the number of efflux pumps increased. However, the rate of this increase was not linear and it is possible that there is a maximum number of Pgp 170 molecules an isolate can express. Nevertheless, the phenomenon is a complex one and other factors and proteins are involved in which the HSP-70 group proteins, detected in the “resistant” isolates, may play a significant role. 相似文献
10.
Mar Pujades-Rodriguez Adam Timmis Dimitris Stogiannis Eleni Rapsomaniki Spiros Denaxas Anoop Shah Gene Feder Mika Kivimaki Harry Hemingway 《PloS one》2014,9(8)