We studied the early stages of pellicle formation by Mycobacterium smegmatis on the surface of a liquid medium [air-liquid interface (A-L)]. Using optical and scanning electron microscopy, we showed the formation of a compact biofilm pellicle from micro-colonies over a period of 8-30 h. The cells in the pellicle changed size and cell division pattern during this period. Based on our findings, we created a model of M. smegmatis A-L early pellicle formation showing the coordinate growth of cells in the micro-colonies and in the homogeneous film between them, where the accessibility to oxygen and nutrients is different. A proteomic approach utilizing high-resolution two-dimensional gel electrophoresis, in combination with mass spectrometry-based protein identification, was used to analyse the protein expression profiles of the different morphological stages of the pellicle. The proteins identified formed four expression groups; the most interesting of these groups contained the proteins with highest expression in the biofilm development phase, when the floating micro-colonies containing long and more robust cells associate into flocs and start to form a compact pellicle. The majority of these proteins, including GroEL1, are involved in cell wall synthesis or modification, mostly through the involvement of mycolic acid biosynthesis, and their expression maxima correlated with the changes in cell size and the rigidity of the bacterial cell wall observed by scanning electron microscopy.

• MeSH
• 2D gelová elektroforéza MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• biofilmy růst a vývoj   MeSH
• biologické modely MeSH
• buněčná stěna metabolismus   MeSH
• kultivační média MeSH
• mikroskopie elektronová rastrovací MeSH
• Mycobacterium smegmatis genetika   růst a vývoj   fyziologie   ultrastruktura   MeSH
• proteomika * MeSH
• regulace genové exprese u bakterií * MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• vzduch MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Gasoline engine emissions have been classified as possibly carcinogenic to humans and represent a significant health risk. In this study, we used MucilAir™, a three-dimensional (3D) model of the human airway, and BEAS-2B, cells originating from the human bronchial epithelium, grown at the air-liquid interface to assess the toxicity of ordinary gasoline exhaust produced by a direct injection spark ignition engine. The transepithelial electrical resistance (TEER), production of mucin, and lactate dehydrogenase (LDH) and adenylate kinase (AK) activities were analyzed after one day and five days of exposure. The induction of double-stranded DNA breaks was measured by the detection of histone H2AX phosphorylation. Next-generation sequencing was used to analyze the modulation of expression of the relevant 370 genes. The exposure to gasoline emissions affected the integrity, as well as LDH and AK leakage in the 3D model, particularly after longer exposure periods. Mucin production was mostly decreased with the exception of longer BEAS-2B treatment, for which a significant increase was detected. DNA damage was detected after five days of exposure in the 3D model, but not in BEAS-2B cells. The expression of CYP1A1 and GSTA3 was modulated in MucilAir™ tissues after 5 days of treatment. In BEAS-2B cells, the expression of 39 mRNAs was affected after short exposure, most of them were upregulated. The five days of exposure modulated the expression of 11 genes in this cell line. In conclusion, the ordinary gasoline emissions induced a toxic response in MucilAir™. In BEAS-2B cells, the biological response was less pronounced, mostly limited to gene expression changes.

• MeSH
• adenylátkinasa metabolismus   MeSH
• bronchy cytologie   MeSH
• dvouřetězcové zlomy DNA MeSH
• elektrická impedance MeSH
• epitelové buňky účinky léků   metabolismus   MeSH
• kultivované buňky MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• lidé MeSH
• muciny metabolismus   MeSH
• testy toxicity metody   MeSH
• transkriptom MeSH
• výfukové emise vozidel toxicita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

In vitro cell models offer a unique opportunity for conducting toxicology research, and the human lung adenocarcinoma cell line A549 is commonly used for toxicology testing strategies. It is essential to determine whether the response of these cells grown in different laboratories is consistent. In this study, A549 cells were grown under both submerged and air-liquid interface (ALI) conditions following an identical cell seeding protocol in two independent laboratories. The cells were switched to the ALI after four days of submerged growth, and their behaviour was compared to submerged conditions. The membrane integrity, cell viability, morphology, and (pro-)inflammatory response upon positive control stimuli were assessed at days 3, 5, and 7 under submerged conditions and at days 5, 7, and 10 at the ALI. Due to the high variability of the results between the two laboratories, the experiment was subsequently repeated using identical reagents at one specific time point and condition (day 5 at the ALI). Despite some variability, the results were more comparable, proving that the original protocol necessitated improvements. In conclusion, the use of detailed protocols and consumables from the same providers, special training of personnel for cell handling, and endpoint analysis are critical to obtain reproducible results across independent laboratories.

• MeSH
• buněčná diferenciace účinky léků   MeSH
• buněčné kultury * MeSH
• buňky A549 MeSH
• epitelové buňky * účinky léků   MeSH
• interleukin-6 metabolismus   MeSH
• interleukin-8 metabolismus   MeSH
• laboratoře MeSH
• lidé MeSH
• lipopolysacharidy farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• reprodukovatelnost výsledků MeSH
• TNF-alfa farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The neurological effects of the coronavirus disease of 2019 (COVID-19) raise concerns about potential long-term consequences, such as an increased risk of Alzheimer's disease (AD). Neuroinflammation and other AD-associated pathologies are also suggested to increase the risk of serious SARS-CoV-2 infection. Anosmia is a common neurological symptom reported in COVID-19 and in early AD. The olfactory mucosa (OM) is important for the perception of smell and a proposed site of viral entry to the brain. However, little is known about SARS-CoV-2 infection at the OM of individuals with AD. METHODS: To address this gap, we established a 3D in vitro model of the OM from primary cells derived from cognitively healthy and AD individuals. We cultured the cells at the air-liquid interface (ALI) to study SARS-CoV-2 infection under controlled experimental conditions. Primary OM cells in ALI expressed angiotensin-converting enzyme 2 (ACE-2), neuropilin-1 (NRP-1), and several other known SARS-CoV-2 receptor and were highly vulnerable to infection. Infection was determined by secreted viral RNA content and confirmed with SARS-CoV-2 nucleocapsid protein (NP) in the infected cells by immunocytochemistry. Differential responses of healthy and AD individuals-derived OM cells to SARS-CoV-2 were determined by RNA sequencing. RESULTS: Results indicate that cells derived from cognitively healthy donors and individuals with AD do not differ in susceptibility to infection with the wild-type SARS-CoV-2 virus. However, transcriptomic signatures in cells from individuals with AD are highly distinct. Specifically, the cells from AD patients that were infected with the virus showed increased levels of oxidative stress, desensitized inflammation and immune responses, and alterations to genes associated with olfaction. These results imply that individuals with AD may be at a greater risk of experiencing severe outcomes from the infection, potentially driven by pre-existing neuroinflammation. CONCLUSIONS: The study sheds light on the interplay between AD pathology and SARS-CoV-2 infection. Altered transcriptomic signatures in AD cells may contribute to unique symptoms and a more severe disease course, with a notable involvement of neuroinflammation. Furthermore, the research emphasizes the need for targeted interventions to enhance outcomes for AD patients with viral infection. The study is crucial to better comprehend the relationship between AD, COVID-19, and anosmia. It highlights the importance of ongoing research to develop more effective treatments for those at high risk of severe SARS-CoV-2 infection.

• MeSH
• Alzheimerova nemoc * metabolismus   MeSH
• anosmie metabolismus   MeSH
• čichová sliznice metabolismus   MeSH
• COVID-19 * MeSH
• lidé MeSH
• neurozánětlivé nemoci MeSH
• SARS-CoV-2 MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Secondary organic aerosols (SOAs) formed from anthropogenic or biogenic gaseous precursors in the atmosphere substantially contribute to the ambient fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] burden, which has been associated with adverse human health effects. However, there is only limited evidence on their differential toxicological impact. OBJECTIVES: We aimed to discriminate toxicological effects of aerosols generated by atmospheric aging on combustion soot particles (SPs) of gaseous biogenic (β-pinene) or anthropogenic (naphthalene) precursors in two different lung cell models exposed at the air-liquid interface (ALI). METHODS: Mono- or cocultures of lung epithelial cells (A549) and endothelial cells (EA.hy926) were exposed at the ALI for 4 h to different aerosol concentrations of a photochemically aged mixture of primary combustion SP and β-pinene (SOAβPIN-SP) or naphthalene (SOANAP-SP). The internally mixed soot/SOA particles were comprehensively characterized in terms of their physical and chemical properties. We conducted toxicity tests to determine cytotoxicity, intracellular oxidative stress, primary and secondary genotoxicity, as well as inflammatory and angiogenic effects. RESULTS: We observed considerable toxicity-related outcomes in cells treated with either SOA type. Greater adverse effects were measured for SOANAP-SP compared with SOAβPIN-SP in both cell models, whereas the nano-sized soot cores alone showed only minor effects. At the functional level, we found that SOANAP-SP augmented the secretion of malondialdehyde and interleukin-8 and may have induced the activation of endothelial cells in the coculture system. This activation was confirmed by comet assay, suggesting secondary genotoxicity and greater angiogenic potential. Chemical characterization of PM revealed distinct qualitative differences in the composition of the two secondary aerosol types. DISCUSSION: In this study using A549 and EA.hy926 cells exposed at ALI, SOA compounds had greater toxicity than primary SPs. Photochemical aging of naphthalene was associated with the formation of more oxidized, more aromatic SOAs with a higher oxidative potential and toxicity compared with β-pinene. Thus, we conclude that the influence of atmospheric chemistry on the chemical PM composition plays a crucial role for the adverse health outcome of emissions. https://doi.org/10.1289/EHP9413.

• MeSH
• aerosoly analýza   MeSH
• endoteliální buňky chemie   metabolismus   MeSH
• látky znečišťující vzduch * analýza   toxicita   MeSH
• lidé MeSH
• pevné částice analýza   MeSH
• plíce metabolismus   MeSH
• saze * MeSH
• senioři MeSH
• stárnutí MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Capillary electrophoresis hyphenated with electrospray mass spectrometry (CE-ESI-MS) has emerged in the past decade as one of the most powerful bioanalytical techniques. As the sensitivity and efficiency of new CE-ESI-MS interface designs are continuously improving, numerical modeling can play important role during their development. In this review, different aspects of computer modeling and simulation of CE-ESI-MS interfaces are comprehensively discussed. Relevant essentials of hydrodynamics as well as state-of-the-art modeling techniques are critically evaluated. Sheath liquid-, sheathless-, and liquid-junction interfaces are reviewed from the viewpoint of multidisciplinary numerical modeling along with details of single and multiphase models together with electric field mediated flows, electrohydrodynamics, and free fluid-surface methods. Practical examples are given to help non-specialists to understand the basic principles and applications. Finally, alternative approaches like air amplifiers are also included. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 34: 558-569, 2015.

• MeSH
• algoritmy MeSH
• chemické modely MeSH
• elektroforéza kapilární přístrojové vybavení   metody   MeSH
• elektromagnetická pole MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací přístrojové vybavení   metody   MeSH
• hydrodynamika MeSH
• lidé MeSH
• počítačová simulace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The kinetics of the ozonation reaction of 1,1-diphenylethylene (DPE) on the surface of ice grains (also called "artificial snow"), produced by shock-freezing of DPE aqueous solutions or DPE vapor-deposition on pure ice grains, was studied in the temperature range of 268 to 188 K. A remarkable and unexpected increase in the apparent ozonation rates with decreasing temperature was evaluated using the Langmuir-Hinshelwood and Eley-Rideal kinetic models, and by estimating the apparent specific surface area of the ice grains. We suggest that an increase of the number of surface reactive sites, and possibly higher ozone uptake coefficients are responsible for the apparent rate acceleration of DPE ozonation at the air-ice interface at lower temperatures. The increasing number of reactive sites is probably related to the fact that organic molecules are displaced more to the top of a disordered interface (or quasi-liquid) layer on the ice surface, which makes them more accessible to the gas-phase reactants. The effect of NaCl as a cocontaminant on ozonation rates was also investigated. The environmental implications of this phenomenon for natural ice/snow are discussed. DPE was selected as an example of environmentally relevant species which can react with ozone. For typical atmospheric ozone concentrations in polar areas (20 ppbv), we estimated that its half-life on the ice surface would decrease from ∼5 days at 258 K to ∼13 h at 188 K at submonolayer DPE loadings.

• MeSH
• led MeSH
• oxidancia chemie   MeSH
• ozon chemie   MeSH
• styreny chemie   MeSH
• teplota MeSH
• vzduch MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A liquid marble is a liquid droplet encapsulated in a hydrophobic powder that adheres to the liquid surface. Liquid marbles preparation is very simple – a small amount of liquid is carefully dripped on the layer of hydrophobic powder consisting of nano- or micro particles, which spread spontaneously at the interface liquid/air. This process results in a liquid marble that has some of the properties of a liquid droplet and, at the same time, behaves as a soft solid. Liquid marbles present an alternative to superhydrophobic surfaces because these particles prevent the liquid to wet and contaminate the carrier surface, be it solid or liquid. The present work focuses on the description of basic properties of liquid marbles; also, an overview is given of possible applications of liquid marbles, e.g. for the transport of small volumes of liquids or powders in microfluidics, for the detection of gases or water contamination or as (bio)microreactors.

• Klíčová slova
• tekuté kuličky,
• MeSH
• chemické látky - účinky a užití * MeSH
• hemaglutinační testy metody   MeSH
• hydrofobní a hydrofilní interakce * MeSH
• klinické laboratorní techniky MeSH
• kultivační techniky MeSH
• výzkum MeSH

Spermatozoa tend to swim near surfaces. Such attraction toward surface vicinity was approximated by the force-dipole theoretical approach and hydrodynamic modeling, but the physical parameters of surfaces have not usually been included in these models and their effect on sperm mobility remains unknown. In spermatozoa, changes in wave parameters, together with rotation around their longitudinal axis and circling appear when movement takes place close to surfaces. Here we show, by analysis of microscopy images (including high-speed video), a strong influence of the liquid-solid interface on sterlet spermatozoa motility characteristics compared with motility near the liquid-gas interface. Sperm cells swam at 16% lower velocity near a liquid-solid interface, rotating at a stable frequency of 25 Hz, each 180° rotation corresponding to one beat cycle and circling clockwise (when observed from top). In case of spermatozoa close to a water-air interface, rotation and circling were sporadic and irregular. Sterlet spermatozoa movement near a surface affects their velocity and possibly causes rotation. These behaviors are highly dependent on the level of suppleness of the interface, as has been previously predicted by modeling. Our results enhance the understanding of how surfaces influence fish spermatozoa motility. These insights on the effects of surfaces on fish spermatozoa motility imply that widely used methods rating sperm motility, such as computer-assisted sperm analysis, might lead to erroneous results. Further study of sperm motility near surfaces is urgently needed to correct our rating methods and better understand sperm behavior in natural conditions. Improved evaluation of sperm motility behavior near surfaces could be used to determine physical properties of aquatic interfaces with various surfaces composed of different materials.

• MeSH
• analýza spermatu veterinární   MeSH
• bičík spermie fyziologie   MeSH
• biologické modely MeSH
• motilita spermií fyziologie   MeSH
• plavání MeSH
• pohyb fyziologie   MeSH
• povrchové vlastnosti MeSH
• rotace MeSH
• ryby fyziologie   MeSH
• spermie fyziologie   MeSH
• životní prostředí MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Air nanobubbles and nanopancakes were investigated in situ by both tapping mode atomic force microscopy (TM AFM) and atomic force nanolithography techniques employing bovine serum albumin (BSA) film supported by highly oriented pyrolytic graphite (HOPG). The BSA denaturation induced by the water-to-ethanol exchange served for conservation of nanobubble and nanopancake sites appearing as imprints in BSA film left by gaseous cavities formerly present on the interface in the aqueous environment. Once the BSA film was gently removed by the nanoshaving technique applied in ethanol, a clean basal plane HOPG area with well-defined dimensions was regenerated. The subsequent reverse ethanol-to-water exchange led to the re-formation of nanopancakes specifically at the nanoshaved area. Our approach paves the way for the study of gaseous nanostructures with defined dimensions, formed at solid-liquid interface under controlled conditions.

• MeSH
• ethanol MeSH
• grafit chemie   MeSH
• mikroskopie atomárních sil MeSH
• nanostruktury chemie   ultrastruktura   MeSH
• nanotechnologie MeSH
• plyny MeSH
• povrchové vlastnosti MeSH
• sérový albumin hovězí chemie   MeSH
• skot MeSH
• voda MeSH
• vzduch MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH