• MeSH
• histologie MeSH
• Publikační typ
• atlasy MeSH

• Konspekt
• Anatomie člověka a srovnávací anatomie
• NLK Obory
• histologie

• MeSH
• pigmentace kůže MeSH
• populační dynamika MeSH
• vitamin D biosyntéza   MeSH

Changes of membrane organization upon cross-linking of its components trigger cell signaling response to various exogenous factors. Cross-linking of raft gangliosides GM1 with cholera toxin (CTxB) was shown to cause microscopic phase separation in model membranes, and the CTxB-GM1 complexes forming a minimal lipid raft unit are the subject of ongoing cell membrane research. Yet, those subdiffraction sized rafts have never been described in terms of size and dynamics. By means of two-color z-scan fluorescence correlation spectroscopy, we show that the nanosized domains are formed in model membranes at lower sphingomyelin (Sph) content than needed for the large-scale phase separation and that the CTxB-GM1 complexes are confined in the domains poorly stabilized with Sph. Förster resonance energy transfer together with Monte Carlo modeling of the donor decay response reveal the domain radius of ~8 nm, which increases at higher Sph content. We observed two types of domains behaving differently, which suggests a dual role of the cross-linker: first, local transient condensation of the GM1 molecules compensating for a lack of Sph and second, coalescence of existing nanodomains ending in large-scale phase separation.

• MeSH
• chemické modely MeSH
• cholerový toxin chemie   MeSH
• fluidita membrány MeSH
• G(M1) gangliosid chemie   MeSH
• lipidové dvojvrstvy chemie   MeSH
• membránové mikrodomény chemie   ultrastruktura   MeSH
• molekulární konformace MeSH
• molekulární modely MeSH
• reagencia zkříženě vázaná chemie   MeSH
• změna skupenství MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Glycosylated sphingolipids (GSLs) are a diverse group of cellular lipids typically reported as being rare in normal mammary tissue. In breast cancer (BCa), GSLs have emerged as noteworthy markers associated with breast cancer stem cells, mediators of phenotypic plasticity, and contributors to cancer cell chemoresistance. GSLs are potential surface markers that can uniquely characterize the heterogeneity of the tumor microenvironment, including cancer cell subpopulations and epithelial-mesenchymal plasticity (EMP). In this study, mass spectrometry analyses of the total sphingolipidome in breast epithelial cells and their mesenchymal counterparts revealed increased levels of Gb3 in epithelial cells and significantly elevated GD2 levels in the mesenchymal phenotype. To elucidate if GSL-related epitopes on BCa cell surfaces reflect EMP and cancer status, we developed and rigorously validated a 12-color spectral flow cytometry panel. This panel enables the simultaneous detection of native GSL epitopes (Gb3, SSEA1, SSEA3, SSEA4, and GD2), epithelial-mesenchymal transition markers (EpCAM, TROP2, and CD9), and lineage markers (CD45, CD31, and CD90) at the single-cell level. Next, the established panel was used for the analysis of BCa primary tumors and revealed surface heterogeneity in SSEA1, SSEA3, SSEA4, GD2, and Gb3, indicative of native epitope presence also on non-tumor cells. These findings further highlighted the phenotype-dependent alterations in GSL surface profiles, with differences between epithelial and stromal cells in the tumor. This study provides novel insights into BCa heterogeneity, shedding light on the potential of native GSL-related epitopes as markers for EMP and cancer status in fresh clinical samples. The developed single-cell approach offers promising avenues for further exploration.

• MeSH
• analýza jednotlivých buněk * metody   MeSH
• epitelo-mezenchymální tranzice * MeSH
• fenotyp MeSH
• glykosfingolipidy * metabolismus   analýza   MeSH
• lidé MeSH
• nádory prsu * metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Animals often change their habitat throughout ontogeny; yet, the triggers for habitat transitions and how these correlate with developmental changes - e.g. physiological, morphological and behavioural - remain largely unknown. Here, we investigated how ontogenetic changes in body coloration and of the visual system relate to habitat transitions in a coral reef fish. Adult dusky dottybacks, Pseudochromis fuscus, are aggressive mimics that change colour to imitate various fishes in their surroundings; however, little is known about the early life stages of this fish. Using a developmental time series in combination with the examination of wild-caught specimens, we revealed that dottybacks change colour twice during development: (i) nearly translucent cryptic pelagic larvae change to a grey camouflage coloration when settling on coral reefs; and (ii) juveniles change to mimic yellow- or brown-coloured fishes when reaching a size capable of consuming juvenile fish prey. Moreover, microspectrophotometric (MSP) and quantitative real-time PCR (qRT-PCR) experiments show developmental changes of the dottyback visual system, including the use of a novel adult-specific visual gene (RH2 opsin). This gene is likely to be co-expressed with other visual pigments to form broad spectral sensitivities that cover the medium-wavelength part of the visible spectrum. Surprisingly, the visual modifications precede changes in habitat and colour, possibly because dottybacks need to first acquire the appropriate visual performance before transitioning into novel life stages.

• MeSH
• barva MeSH
• biologické modely MeSH
• časové faktory MeSH
• ekosystém * MeSH
• fylogeneze MeSH
• fyziologická adaptace MeSH
• korálové útesy * MeSH
• kůže cytologie   MeSH
• kvantitativní znak dědičný MeSH
• mimikry * MeSH
• opsiny genetika   MeSH
• pigmentace fyziologie   MeSH
• predátorské chování MeSH
• regulace genové exprese MeSH
• ryby růst a vývoj   fyziologie   MeSH
• zrak fyziologie   MeSH
• zrakové dráhy fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Austrálie MeSH

Many animals use carotenoid pigments to produce yellow, orange, and red coloration. In birds, at least 10 carotenoid compounds have been documented in red feathers; most of these are produced through metabolic modification of dietary precursor compounds. However, it is poorly understood how lineages have evolved the biochemical mechanisms for producing red coloration. We used high-performance liquid chromatography to identify the carotenoid compounds present in feathers from 15 species across two clades of blackbirds (the meadowlarks and allies, and the caciques and oropendolas; Icteridae), and mapped their presence or absence on a phylogeny. We found that the red plumage found in meadowlarks includes different carotenoid compounds than the red plumage found in caciques, indicating that these gains of red color are convergent. In contrast, we found that red coloration in two closely related lineages of caciques evolved twice by what appear to be similar biochemical mechanisms. The C4-oxygenation of dietary carotenoids was responsible for each observed transition from yellow to red plumage coloration, and has been commonly reported by other researchers. This suggests that the C4-oxygenation pathway may be a readily evolvable means to gain red coloration using carotenoids.

• MeSH
• fylogeneze MeSH
• karotenoidy genetika   metabolismus   MeSH
• molekulární evoluce * MeSH
• oxidace-redukce MeSH
• peří anatomie a histologie   MeSH
• pigmentace genetika   MeSH
• zpěvní ptáci anatomie a histologie   klasifikace   genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

BACKGROUND: Parrots are one of the most frequently kept and bred bird orders in captivity. This increases poaching and thus the potential importance of captive populations for rescue programmes managed by zoos and related institutions. Both captive breeding and poaching are selective and may be influenced by the attractiveness of particular species to humans. In this paper, we tested the hypothesis that the size of zoo populations is not only determined by conservation needs, but also by the perceived beauty of individual parrot species assessed by human observers. METHODOLOGY/PRINCIPAL FINDINGS: For the purpose of data collection, we defined four sets of species (40 parrots, 367 parrots, 34 amazons, 17 macaws). Then, we asked 776 human respondents to evaluate parrot pictures of the selected species according to perceived beauty and we analyzed its association with color and morphological characters. Irrespective of the species set, we found a good agreement among the respondents. The preferred species tended to be large, colorful, and long-tailed. CONCLUSIONS/SIGNIFICANCE: We repeatedly confirmed significant, positive association between the perceived beauty and the size of worldwide zoo population. Moreover, the range size and body size appeared to be significant predictors of zoo population size. In contrast, the effects of other explanatory variables, including the IUCN (International Union for Conservation of Nature) listing, appeared insignificant. Our results may suggest that zoos preferentially keep beautiful parrots and pay less attention to conservation needs.

• MeSH
• chov MeSH
• dospělí MeSH
• krása MeSH
• lidé MeSH
• mladý dospělý MeSH
• ohrožené druhy MeSH
• papouškovití fyziologie   MeSH
• populační dynamika MeSH
• zvířata v ZOO fyziologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The main objective of the presented research was to prepare an innovative carrier as a filler for detection tubes in the form of double-coated pellets with a very significant color transition during the detection of cholinesterase inhibitors such as nerve agents, organophosphorus or carbamate insecticides in liquids that is observable visually and also spectrophotometrically at 412 nm. The pellet cores were prepared by the extrusion/spheronization method. Consecutively, two different coats were applied on the pellet cores in the coating device using the Wurster column method. To increase the color change intensity, the second semipermeable coat based on Eudragit® RL was applied on top of the first coat, which was formed by butyrylcholinesterase immobilized in hydroxypropyl methylcellulose. Prepared samples differing in thickness of the second coat were evaluated for their quality parameters, enzymatic activity and inhibition. The detection mechanism was based on the standard Ellman's colorimetric reaction. It was observed that the semipermeable coat prevented leaching of the enzyme into the solution and led to an increased intensity of color transition from white - yellow to white - deep yellow/orange, thus enabling a more accurate visual detection. This system allows easy, rapid and safe identification of cholinesterase inhibitors in liquids, especially chemical warfare agents.

• MeSH
• butyrylcholinesterasa chemie   MeSH
• cholinesterasové inhibitory analýza   MeSH
• deriváty hypromelózy chemie   MeSH
• kolorimetrie metody   MeSH
• polymery chemie   MeSH
• roztoky chemie   MeSH
• spektrofotometrie metody   MeSH
• Publikační typ
• časopisecké články MeSH

Nervově paralytické látky jsou v současné době často zneužívané při teroristických útocích nebo atentátech. V takových případech je potřeba jejich rychlé, přesné a snadné detekce přímo v terénu. To umožňují detekční trubičky, které obsahují jako náplň pelety s imobilizovanou cholinesterasou a detekční činidla. Princip jejich detekce je založen na vysoce citlivé enzymatické Ellmanově reakci, při které v nepřítomnosti inhibitorů cholinesteras dochází na peletách ke vzniku žluté barvy, naopak v jejich přítomnosti si nosič ponechává původní barvu. Rychlost reakce, její citlivost a zřetelnost barevného přechodu při detekci jsou pak stěžejními body výzkumu. V rámci experimentu byly připraveny pelety s dvojitým obalem, kde první obal obsahoval enzym butyrylcholinesterasu imobilizovanou v hypromelose a druhý obal byl tvořený ethylcelulosou a triethyl citrátem. Na základě vlastností těchto vzorků byly dále připraveny i šarže obsahující laktosu dispergovanou v ethylcelulosovém obalu, od které se očekával vliv na zvýšení permeability obalu, a tím i rychlosti detekce a intenzity zbarvení. U nosičů byla kromě vybraných fyzikálně-chemických vlastností hodnocena aktivita enzymu, jeho citlivost a intenzita barevného přechodu. Šarže vykazující nejlepší vlastnosti byly podrobeny 24měsíčnímu testu stability při třech různých teplotách a vlhkostech.

Currently, nerve agents are often used in terrorist attacks or assassinations. In such cases, it is necessary to detect them quickly, accurately and easily right in the field. Detection tubes, which are small devices containing pellets with immobilized cholinesterase and detection reagents, meet these conditions. Their detection mechanism is based on a highly sensitive enzymatic Ellman reaction, when in the absence of cholinesterase inhibitors the pellets develop a visible yellow color, whereas in their presence the carriers retain the original color. The rate of reaction, its sensitivity and the distinct color transition are the key points of the research. In this experiment, double-coated pellets were prepared. The first coating contained the butyrylcholinesterase immobilized in hypromellose, while the second coating consisted of ethylcellulose and triethyl citrate. Based on the properties of such carriers, samples containing lactose dispersed in the ethylcellulose coating were also prepared, which was expected to have an effect on increasing the permeability of the coating and hence the detection rate and color intensity. In addition to selected physicochemical properties, carriers were evaluated for enzyme activity, sensitivity and color transition intensity. Samples showing the best properties were subjected to a 24-months stability test at three different temperatures and humidity.

• Klíčová slova
• ethylcelulosa, pelety, detekční trubička, nervově paralytická látka,
• MeSH
• cholinesterasy MeSH
• lidé MeSH
• nervová bojová látka * izolace a purifikace   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Pellets with an immobilized enzyme (acetyl- or butyrylcholinesterase) are the up-to-date type of carriers used for the detection of nerve agents (soman, sarin, tabun, VX, Novichok) and other cholinesterase inhibitors such as organophosphate and carbamate insecticides (parathion, malathion). They are used in the glass detection tubes as a layer containing the enzyme together with the second layer, which contains a colorimetric reagent and substrate. The detection method is based on the visually or spectrophotometrically observable Ellman's reaction, which develops a yellow color in the absence of the cholinesterase inhibitor; otherwise, the detector preserves its original color (preferably white). This reaction occurs very fast and has a high sensitivity to nerve agents but it suffers from an indistinctive color transition from white to yellow. In the presented study, a new approach with the use of the synergic effect of magnesium aluminometasilicate with a high surface area marketed as Neusilin®US2 and a protective semipermeable Eudragit® RL layer was utilized. The prepared pellets have been evaluated for their properties such as the activity of the enzyme, intensity of the developed yellow color, sensitivity to cholinesterase inhibitor physostigmine, which acts as a nerve agent simulant, and physical parameters such as hardness, pycnometric density and sphericity. After the initial evaluation, all samples underwent a stability test under three different storage conditions for 24 months during which they were evaluated at given time points (0, 3, 6, 12 and 24 months). It was found that the prepared samples achieved a much higher intensity of developed yellow color than in the published studies while maintaining similar or better sensitivity, speed of detection and suitable physico-chemical properties.

• MeSH
• acetylcholinesterasa chemie   MeSH
• butyrylcholinesterasa chemie   MeSH
• časové faktory MeSH
• cholinesterasové inhibitory analýza   MeSH
• enzymy imobilizované chemie   MeSH
• kolorimetrie metody   MeSH
• nervová bojová látka analýza   MeSH
• polymery chemie   MeSH
• silikáty chemie   MeSH
• sloučeniny hliníku chemie   MeSH
• sloučeniny hořčíku chemie   MeSH
• Publikační typ
• časopisecké články MeSH