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Lobaz V, Liščáková V, Sedlák F, Musil D, Petrova SL, Šeděnková I, Pánek J, Kučka J, Konefał R, Tihlaříková E, Neděla V, Pankrác J, Šefc L, Hrubý M, Šácha P, Štěpánek P. Tuning polymer-blood and polymer-cytoplasm membrane interactions by manipulating the architecture of poly(2-oxazoline) triblock copolymers. Colloids Surf B Biointerfaces 2023; 231:113564. [PMID: 37742364 DOI: 10.1016/j.colsurfb.2023.113564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
Bioactive moieties designed to bind to cell membrane receptors benefit from coupling with polymeric carriers that have enhanced affinity to the cell membrane. When bound to the cell surface, such carriers create a "2D solution" of a ligand with a significantly increased concentration near a membrane-bound receptor compared to a freely water-soluble ligand. Bifunctional polymeric carriers based on amphiphilic triblock copolymers were synthesized from 2-pent-4-ynyl oxazoline, 2-nonyl oxazoline and 2-ethyl oxazoline. Their self-assembly and interactions with plasma proteins and HEK 293 cells were studied in detail. The affinity of these triblock copolymers to HEK 293 cell membranes and organ tissues was tunable by the overall hydrophobicity of the polymer molecule, which is determined by the length of the hydrophobic and hydrophilic blocks. The circulation time and biodistribution of three representative triblock copolymers were monitored after intravenous administration to C57BL/6 albino mice. A prolonged circulation time was observed for polymers with longer hydrophobic blocks, despite their molecular weight being below the renal threshold.
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Affiliation(s)
- Volodymyr Lobaz
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia.
| | - Veronika Liščáková
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 542/2, 160 00 Prague 6, Czechia; Laboratory of Theranostics, Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, U Nemocnice 5, 128 53 Prague 2, Czechia
| | - František Sedlák
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 542/2, 160 00 Prague 6, Czechia; Laboratory of Theranostics, Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, U Nemocnice 5, 128 53 Prague 2, Czechia
| | - Dominik Musil
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 542/2, 160 00 Prague 6, Czechia; Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague 2, Czechia
| | - Svetlana Lukáš Petrova
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Ivana Šeděnková
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Jiří Pánek
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Jan Kučka
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Rafał Konefał
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61 200 Brno, Czechia
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61 200 Brno, Czechia
| | - Jan Pankrác
- Center for Advanced Preclinical Imaging (CAPI), First Faculty of Medicine, Charles University, Salmovská 3, Prague 2, Czechia
| | - Luděk Šefc
- Center for Advanced Preclinical Imaging (CAPI), First Faculty of Medicine, Charles University, Salmovská 3, Prague 2, Czechia
| | - Martin Hrubý
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
| | - Pavel Šácha
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 542/2, 160 00 Prague 6, Czechia
| | - Petr Štěpánek
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského n. 1888/2, 162 06 Prague 6, Czechia
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Bačovský V, Čegan R, Tihlaříková E, Neděla V, Hudzieczek V, Smrža L, Janíček T, Beneš V, Hobza R. Chemical genetics in Silene latifolia elucidate regulatory pathways involved in gynoecium development. J Exp Bot 2022; 73:2354-2368. [PMID: 35045170 DOI: 10.1093/jxb/erab538] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Dioecious plants possess diverse sex determination systems and unique mechanisms of reproductive organ development; however, little is known about how sex-linked genes shape the expression of regulatory cascades that lead to developmental differences between sexes. In Silene latifolia, a dioecious plant with stable dimorphism in floral traits, early experiments suggested that female-regulator genes act on the factors that determine the boundaries of the flower whorls. To identify these regulators, we sequenced the transcriptome of male flowers with fully developed gynoecia, induced by rapid demethylation in the parental generation. Eight candidates were found to have a positive role in gynoecium promotion, floral organ size, and whorl boundary, and affect the expression of class B MADS-box flower genes. To complement our transcriptome analysis, we closely examined the floral organs in their native state using field emission environmental scanning electron microscopy, and examined the differences between females and androhermaphrodites in their placenta and ovule organization. Our results reveal the regulatory pathways potentially involved in sex-specific flower development in the classical model of dioecy, S. latifolia. These pathways include previously hypothesized and unknown female-regulator genes that act on the factors that determine the flower boundaries, and a negative regulator of anther development, SUPERMAN-like (SlSUP).
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Affiliation(s)
- Václav Bačovský
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Radim Čegan
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 64 Brno, Czech Republic
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 64 Brno, Czech Republic
| | - Vojtěch Hudzieczek
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Lubomír Smrža
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Tomáš Janíček
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Vladimír Beneš
- EMBL Genomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, D-69117 Heidelberg, Germany
| | - Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 65 Brno, Czech Republic
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Závacká K, Neděla V, Tihlaříková E, Šabacká P, Maxa J, Heger D. ESEM Methodology for the Study of Ice Samples at Environmentally Relevant Subzero Temperatures: "Subzero ESEM". Microsc Microanal 2022; 28:196-209. [PMID: 34937589 DOI: 10.1017/s1431927621013854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Frozen aqueous solutions are an important subject of study in numerous scientific branches including the pharmaceutical and food industry, atmospheric chemistry, biology, and medicine. Here, we present an advanced environmental scanning electron microscope methodology for research of ice samples at environmentally relevant subzero temperatures, thus under conditions in which it is extremely challenging to maintain the thermodynamic equilibrium of the specimen. The methodology opens possibilities to observe intact ice samples at close to natural conditions. Based on the results of ANSYS software simulations of the surface temperature of a frozen sample, and knowledge of the partial pressure of water vapor in the gas mixture near the sample, we monitored static ice samples over several minutes. We also discuss possible artifacts that can arise from unwanted surface ice formation on, or ice sublimation from, the sample, as a consequence of shifting conditions away from thermodynamic equilibrium in the specimen chamber. To demonstrate the applicability of the methodology, we characterized how the true morphology of ice spheres containing salt changed upon aging and the morphology of ice spheres containing bovine serum albumin. After combining static observations with the dynamic process of ice sublimation from the sample, we can attain images with nanometer resolution.
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Affiliation(s)
- Kamila Závacká
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61264Brno, Czech Republic
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61264Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61264Brno, Czech Republic
| | - Pavla Šabacká
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61264Brno, Czech Republic
| | - Jiří Maxa
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 61264Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500Brno, Czech Republic
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Stelate A, Tihlaříková E, Schwarzerová K, Neděla V, Petrášek J. Correlative Light-Environmental Scanning Electron Microscopy of Plasma Membrane Efflux Carriers of Plant Hormone Auxin. Biomolecules 2021; 11:1407. [PMID: 34680040 PMCID: PMC8533460 DOI: 10.3390/biom11101407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 12/17/2022] Open
Abstract
Fluorescence light microscopy provided convincing evidence for the domain organization of plant plasma membrane (PM) proteins. Both peripheral and integral PM proteins show an inhomogeneous distribution within the PM. However, the size of PM nanodomains and protein clusters is too small to accurately determine their dimensions and nano-organization using routine confocal fluorescence microscopy and super-resolution methods. To overcome this limitation, we have developed a novel correlative light electron microscopy method (CLEM) using total internal reflection fluorescence microscopy (TIRFM) and advanced environmental scanning electron microscopy (A-ESEM). Using this technique, we determined the number of auxin efflux carriers from the PINFORMED (PIN) family (NtPIN3b-GFP) within PM nanodomains of tobacco cell PM ghosts. Protoplasts were attached to coverslips and immunostained with anti-GFP primary antibody and secondary antibody conjugated to fluorochrome and gold nanoparticles. After imaging the nanodomains within the PM with TIRFM, the samples were imaged with A-ESEM without further processing, and quantification of the average number of molecules within the nanodomain was performed. Without requiring any post-fixation and coating procedures, this method allows to study details of the organization of auxin carriers and other plant PM proteins.
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Affiliation(s)
- Ayoub Stelate
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague 2, Czech Republic; (A.S.); (K.S.)
| | - Eva Tihlaříková
- Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Královopolská 147, 612 64 Brno, Czech Republic; (E.T.); (V.N.)
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague 2, Czech Republic; (A.S.); (K.S.)
| | - Vilém Neděla
- Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Královopolská 147, 612 64 Brno, Czech Republic; (E.T.); (V.N.)
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague 2, Czech Republic; (A.S.); (K.S.)
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Hemala V, Kment P, Tihlaříková E, Neděla V, Malenovský I. External structures of the metathoracic scent gland efferent system in the true bug superfamily Pyrrhocoroidea (Hemiptera: Heteroptera: Pentatomomorpha). Arthropod Struct Dev 2021; 63:101058. [PMID: 34034200 DOI: 10.1016/j.asd.2021.101058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Pyrrhocoroidea represents an important group of true bugs (Insecta: Hemiptera: Heteroptera) which includes fire bugs, cotton stainers and other taxa widely used in experimental studies or known as pests. However, the morphology and phylogeny of Pyrrhocoroidea have been only poorly studied so far. Here, structures of the external scent efferent system of the metathoracic scent glands are examined in 64 out of 71 currently valid genera of Pyrrhocoroidea and scanning electron micrographs are provided for most taxa. Several characters are revealed which define each of the three higher taxa within Pyrrhocoroidea: Larginae (small auriculate peritreme lacking manubrium and median furrow; metathoracic spiracle never surrounded by evaporatorium), Physopeltinae (large, widely open ostiole; large peritremal disc with manubrium [new term], lacking median furrow; mace-like mycoid filter processes of equal shape and size on both anterior and posterior margins of metathoracic spiracle), and Pyrrhocoridae (elongate auriculate peritreme with deep median furrow). Within Pyrrhocoridae, three main types (A, B and C) of the external scent efferent system are distinguished, differring in the amount of reductions. The findings are interpreted in the context of phylogenetic hypotheses available for Pyrrhocoroidea and their close relatives, Coreoidea and Lygaeoidea. An updated identification key to the families and subfamilies of Pyrrhocoroidea applicable for both sexes is provided.
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Affiliation(s)
- Vladimír Hemala
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic.
| | - Petr Kment
- Department of Entomology, National Museum, Cirkusová 1740, 193 00, Prague, Horní Počernice, Czech Republic.
| | - Eva Tihlaříková
- Institute of Scientific Instruments, Czech Academy of Sciences, Královopolská 147, 612 64, Brno, Czech Republic.
| | - Vilém Neděla
- Institute of Scientific Instruments, Czech Academy of Sciences, Královopolská 147, 612 64, Brno, Czech Republic.
| | - Igor Malenovský
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic.
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Bathoova M, Švubová R, Bokor B, Neděla V, Tihlaříková E, Martinka M. Silicon triggers sorghum root enzyme activities and inhibits the root cell colonization by Alternaria alternata. Planta 2021; 253:29. [PMID: 33423117 DOI: 10.1007/s00425-020-03560-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Silicon inhibits the growth of Alternaria alternata into sorghum root cells by maintaining their integrity through stimulating biochemical defense reactions rather than by silica-based physical barrier creation. Although the ameliorating effect of silicon (Si) on plant resistance against fungal pathogens has been proven, the mechanism of its action needs to be better understood on a cellular level. The present study explores the effect of Si application in sorghum roots infected with fungus Alternaria alternata under controlled in vitro conditions. Detailed anatomical and cytological observations by both fluorescent and electron microscopy revealed that Si supplementation results in the inhibition of fungal hyphae growth into the protoplast of root cells. An approach of environmental scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy enabling spatial detection of Si even at low concentrations showed that there is no continual solid layer of silica in the root cell walls of the rhizodermis, mesodermis and exodermis physically blocking the fungal growth into the protoplasts. Additionally, biochemical evidence suggests that Si speeds up the onset of activities of phenylpropanoid pathway enzymes phenylalanine ammonia lyase, peroxidases and polyphenol oxidases involved in phenolic compounds production and deposition to plant cell walls. In conclusion, Si alleviates the negative impact of A. alternata infection by limiting hyphae penetration through sorghum root cell walls into protoplasts, thus maintaining their structural and functional integrity. This might occur by triggering plant biochemical defense responses rather than by creating compact Si layer deposits.
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Affiliation(s)
- Monika Bathoova
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic.
| | - Renáta Švubová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
| | - Boris Bokor
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
- Comenius University Science Park, Comenius University in Bratislava, Ilkovicova 8, 841 04, Bratislava, Slovak Republic
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 00, Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Kralovopolska 147, 612 00, Brno, Czech Republic
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina, Ilkovicova 6, 842 15, Bratislava 4, Slovak Republic
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Vetráková Ľ, Neděla V, Runštuk J, Tihlaříková E, Heger D, Shalaev E. Dynamical in-situ observation of the lyophilization and vacuum-drying processes of a model biopharmaceutical system by an environmental scanning electron microscope. Int J Pharm 2020; 585:119448. [PMID: 32461002 DOI: 10.1016/j.ijpharm.2020.119448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/23/2020] [Accepted: 05/18/2020] [Indexed: 01/22/2023]
Abstract
The paper discusses the real-time monitoring of the changing sample morphology during the entire lyophilization (freeze-drying) and vacuum-drying processes of model biopharmaceutical solutions by using an environmental scanning electron microscope (ESEM); the device's micromanipulators were used to study the interior of the samples in-situ without exposing the samples to atmospheric water vapor. The individual collapse temperatures (Tc) of the formulations, pure bovine serum albumin (BSA) and BSA/sucrose mixtures, ranged from -5 to -29 °C. We evaluated the impact of the freezing method (spontaneous freezing, controlled ice nucleation, and spray freezing) on the morphologies of the lyophiles at the constant drying temperature of -20 °C. The formulations with Tc above -20 °C resulted in the lyophiles' morphologies significantly dependent on the freezing method. We interpret the observations as an interplay of the freezing rates and directionalities, both of which markedly influence the morphologies of the frozen formulations, and, subsequently, the drying process and the mechanical stability of the freeze-dried cake. The formulation with Tc below -20 °C yielded a collapsed cake with features independent of the freezing method. The vacuum-drying produced a material with a smooth and pore-free surface, where deep cracks developed at the end of the process.
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Affiliation(s)
- Ľubica Vetráková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic.
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Runštuk
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Evgenyi Shalaev
- Pharmaceutical Development, Allergan plc, Irvine, CA, United States.
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Hradilová J, Hradil D, Pech M, Bezdička P, Neděla V, Tihlaříková E, Targowski P. Complementary use of X-ray based imaging and analytical methods in the investigation of miniature portraits. Microchem J 2020. [DOI: 10.1016/j.microc.2019.104371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Neděla V, Tihlaříková E, Maxa J, Imrichová K, Bučko M, Gemeiner P. Simulation-based optimisation of thermodynamic conditions in the ESEM for dynamical in-situ study of spherical polyelectrolyte complex particles in their native state. Ultramicroscopy 2020; 211:112954. [PMID: 32018072 DOI: 10.1016/j.ultramic.2020.112954] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/23/2020] [Accepted: 01/26/2020] [Indexed: 11/18/2022]
Abstract
We present a complex analysis and optimisation of dynamic conditions in the environmental scanning electron microscope (ESEM) to allow in-situ observation of extremely delicate wet bio-polymeric spherical particles in their native state. According to the results of gas flow and heat transfer simulations, we were able to develop an improved procedure leading to thermodynamic equilibrium between the sample and chamber environment. To quantify and hence minimise the extent of any sample deformation during specimen chamber pumping, a strength-stress analysis is used. Monte Carlo simulations of beam-gas, -water, and -sample interactions describe beam scattering, absorbed energy, interaction volume and the emission of signal electrons in the ESEM. Finally, we discuss sample damage as a result of drying and the production of beam-induced free radicals. Based on all experimental and simulation results we introduce a Delicate Sample Observation Strategy for the ESEM. We show how this strategy can be applied to the characterization of polyelectrolyte complex spherical particles containing immobilized recombinant cells E. coli overexpressing cyclohexanone monooxygenase, used as a model biocatalyst. We present the first native-state electron microscopy images of the viscous core of a halved polyelectrolyte complex capsule containing living cells.
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Affiliation(s)
- Vilém Neděla
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic.
| | - Eva Tihlaříková
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Jiří Maxa
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Kamila Imrichová
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Marek Bučko
- Institute of Chemistry, Centre for Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
| | - Peter Gemeiner
- Institute of Chemistry, Centre for Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
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Tihlaříková E, Neděla V, Đorđević B. In-situ preparation of plant samples in ESEM for energy dispersive x-ray microanalysis and repetitive observation in SEM and ESEM. Sci Rep 2019; 9:2300. [PMID: 30783188 PMCID: PMC6381206 DOI: 10.1038/s41598-019-38835-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 01/07/2019] [Indexed: 11/25/2022] Open
Abstract
The Extended Low Temperature Method (ELTM) for the in-situ preparation of plant samples in an environmental scanning electron microscope enables carrying out repetitive topographical and material analysis at a higher resolution in the vacuum conditions of a scanning electron microscope or in the low gas pressure conditions of an environmental scanning electron microscope. The method does not require any chemical intervention and is thus suitable for imaging delicate structures rarely observable with common treatment methods. The method enables both sample stabilization as close to their native state as possible, as well as the transfer of the same sample from a low vacuum to an atmospheric condition for sample storage or later study. It is impossible for wet samples in the environmental scanning electron microscope. Our studies illustrate the high applicability of the ELTM for different types of plant tissue, from imaging of plant waxes at higher resolution, the morphological study of highly susceptible early somatic embryos to the elemental microanalysis of root cells. The method established here provides a very fast, universal and inexpensive solution for plant sample treatment usable in a commercial environmental scanning electron microscope equipped with a cooling Peltier stage.
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Affiliation(s)
- Eva Tihlaříková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, 612 00, Czech Republic.
| | - Vilém Neděla
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, 612 00, Czech Republic
| | - Biljana Đorđević
- Department of Plant Biology, Mendel University in Brno, Brno, 613 00, Czech Republic
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Michaloudi E, Papakostas S, Stamou G, Neděla V, Tihlaříková E, Zhang W, Declerck SAJ. Reverse taxonomy applied to the Brachionus calyciflorus cryptic species complex: Morphometric analysis confirms species delimitations revealed by molecular phylogenetic analysis and allows the (re)description of four species. PLoS One 2018; 13:e0203168. [PMID: 30235243 PMCID: PMC6147415 DOI: 10.1371/journal.pone.0203168] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/14/2018] [Indexed: 12/13/2022] Open
Abstract
The discovery and exploration of cryptic species have been profoundly expedited thanks to developments in molecular biology and phylogenetics. In this study, we apply a reverse taxonomy approach to the Brachionus calyciflorus species complex, a commonly studied freshwater monogonont rotifer. By combining phylogenetic, morphometric and morphological analyses, we confirm the existence of four cryptic species that have been recently suggested by a molecular study. Based on these results and according to an exhaustive review of the taxonomic literature, we name each of these four species and provide their taxonomic description alongside a diagnostic key.
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Affiliation(s)
- Evangelia Michaloudi
- Department of Zoology, School of Biology, Aristotle University of Thessaloniki, Τhessaloniki, Greece
| | - Spiros Papakostas
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
| | - Georgia Stamou
- Department of Zoology, School of Biology, Aristotle University of Thessaloniki, Τhessaloniki, Greece
| | - Vilém Neděla
- Institute of Scientific Instruments, Academy Of Sciences of the Czech Republic, Brno, Czech Republic
| | - Eva Tihlaříková
- Institute of Scientific Instruments, Academy Of Sciences of the Czech Republic, Brno, Czech Republic
| | - Wei Zhang
- Netherlands Institute of Ecology, Department of Aquatic Ecology, Wageningen, The Netherlands
| | - Steven A. J. Declerck
- Netherlands Institute of Ecology, Department of Aquatic Ecology, Wageningen, The Netherlands
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Đorđević B, Neděla V, Tihlaříková E, Trojan V, Havel L. Effects of copper and arsenic stress on the development of Norway spruce somatic embryos and their visualization with the environmental scanning electron microscope. N Biotechnol 2018; 48:35-43. [PMID: 29782934 DOI: 10.1016/j.nbt.2018.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 05/17/2018] [Accepted: 05/17/2018] [Indexed: 11/17/2022]
Abstract
Somatic embryogenesis is an important biotechnological technique which can be used in studies associated with environmental stress. Four embryogenic cell lines of Norway spruce were grown on media enriched with copper and arsenic in concentration ranges 50-500 μM and 10-50 μM, respectively. The effects were observed during subsequent stages of somatic embryogenesis, the characteristics evaluated being proliferation potential, average number of somatic embryos obtained per g/fresh weight, morphology of developed somatic embryos, metal uptake, and microanalysis of macro- and micronutrients uptake. Copper and arsenic at higher concentrations significantly reduced the growth of early somatic embryos. In almost all treatments, the cell line V-1-3 showed the best performance compared with the other lines tested. Environmental scanning electron microscopy was used to visualize and identify morphological abnormalities in the development of somatic embryos. Abnormalities observed were classified into several categories: meristemless somatic embryos, somatic embryos with disrupted meristem, reduced number of cotyledons, single cotyledon and fused cotyledons. With the application of a low temperature method for the environmental scanning electron microscope, samples were stabilized and whole meristems could be investigated in their native state. As far as we are aware, this is the first report of the effect of copper and arsenic during the process of somatic embryogenesis and the first to evaluate the content of macro and micronutrients uptake in Norway spruce.
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Affiliation(s)
- Biljana Đorđević
- Department of Plant Biology, Mendel University in Brno, Zemědělská 1, Brno 613 00, Czech Republic.
| | - Vilém Neděla
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, Brno 612 64, Czech Republic
| | - Eva Tihlaříková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, Brno 612 64, Czech Republic
| | - Václav Trojan
- Department of Plant Biology, Mendel University in Brno, Zemědělská 1, Brno 613 00, Czech Republic
| | - Ladislav Havel
- Department of Plant Biology, Mendel University in Brno, Zemědělská 1, Brno 613 00, Czech Republic
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Kulich I, Vojtíková Z, Sabol P, Ortmannová J, Neděla V, Tihlaříková E, Žárský V. Exocyst Subunit EXO70H4 Has a Specific Role in Callose Synthase Secretion and Silica Accumulation. Plant Physiol 2018; 176:2040-2051. [PMID: 29301954 PMCID: PMC5841730 DOI: 10.1104/pp.17.01693] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/02/2018] [Indexed: 05/20/2023]
Abstract
Biogenesis of the plant secondary cell wall involves many important aspects, such as phenolic compound deposition and often silica encrustation. Previously, we demonstrated the importance of the exocyst subunit EXO70H4 for biogenesis of the trichome secondary cell wall, namely for deposition of the autofluorescent and callose-rich cell wall layer. Here, we reveal that EXO70H4-driven cell wall biogenesis is constitutively active in the mature trichome, but also can be activated elsewhere upon pathogen attack, giving this study a broader significance with an overlap into phytopathology. To address the specificity of EXO70H4 among the EXO70 family, we complemented the exo70H4-1 mutant by 18 different Arabidopsis (Arabidopsis thaliana) EXO70 paralogs subcloned under the EXO70H4 promoter. Only EXO70H4 had the capacity to rescue the exo70H4-1 trichome phenotype. Callose deposition phenotype of exo70H4-1 mutant is caused by impaired secretion of PMR4, a callose synthase responsible for the synthesis of callose in the trichome. PMR4 colocalizes with EXO70H4 on plasma membrane microdomains that do not develop in the exo70H4-1 mutant. Using energy-dispersive x-ray microanalysis, we show that both EXO70H4- and PMR4-dependent callose deposition in the trichome are essential for cell wall silicification.
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Affiliation(s)
- Ivan Kulich
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Zdeňka Vojtíková
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Peter Sabol
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Jitka Ortmannová
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Vilém Neděla
- Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Eva Tihlaříková
- Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Neděla V, Tihlaříková E, Hřib J. The low-temperature method for study of coniferous tissues in the environmental scanning electron microscope. Microsc Res Tech 2014; 78:13-21. [DOI: 10.1002/jemt.22439] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Vilém Neděla
- ASCR, Institute of Scientific Instruments; Kralovopolska 147 612 00 Brno Czech Republic
| | - Eva Tihlaříková
- ASCR, Institute of Scientific Instruments; Kralovopolska 147 612 00 Brno Czech Republic
| | - Jiří Hřib
- Department of Plant Biology, Faculty of Agronomy; Mendel University of Agriculture and Forestry; Zemedelska 1 613 00 Brno Czech Republic
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Abstract
In this paper we introduce new methodology for the observation of living biological samples in an environmental scanning electron microscope (ESEM). The methodology is based on an unconventional initiation procedure for ESEM chamber pumping, free from purge-flood cycles, and on the ability to control thermodynamic processes close to the sample. The gradual and gentle change of the working environment from air to water vapor enables the study of not only living samples in dynamic in situ experiments and their manifestation of life (sample walking) but also its experimentally stimulated physiological reactions. Moreover, Monte Carlo simulations of primary electron beam energy losses in a water layer on the sample surface were studied; consequently, the influence of the water thickness on radiation, temperature, or chemical damage of the sample was considered.
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Affiliation(s)
- Eva Tihlaříková
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno 612 64, Czech Republic
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