1. Comparative ultrastructure of cells and cuticle in the anterior chamber and papillate region of Porcellio scaber (Crustacea, Isopoda) hindgutUrban Bogataj, Monika Praznik, Polona Mrak, Jasna Štrus, Magda Tušek-Žnidarič, Nada Žnidaršič, 2018, izvirni znanstveni članek Povzetek: Isopod hindgut consists of two anatomical and functional parts, the anterior chamber, and the papillate region. This study provides a detailed ultrastructural comparison of epithelial cells in the anterior chamber and the papillate region with focus on cuticle ultrastructure, apical and basal plasma membrane labyrinths, and cell junctions. Na+/K+-ATPase activity in the hindgut epithelial cells was demonstrated by cytochemical localisation. The main difference in cuticle ultrastructure is in the thickness of epicuticle which is almost as thick as the procuticle in the papillate region and only about one sixth of the thickness of procuticle in the anterior chamber. The apical plasma membrane in both hindgut regions forms an apical plasma membrane labyrinth of cytoplasmic strands and extracellular spaces. In the papillate region the membranous infoldings are deeper and the extracellular spaces are wider. The basal plasma membrane is extensively infolded and associated with numerous mitochondria in the papillate region, while it forms relatively scarce basal infoldings in the anterior chamber. The junctional complex in both hindgut regions consists of adherens and septate junctions. Septate junctions are more extensive in the papillate region. Na+/K+-ATPase was located mostly in the apical plasma membranes in both hindgut regions. The ultrastructural features of hindgut cuticle are discussed in comparison to exoskeletal cuticle and to cuticles of other arthropod transporting epithelia from the perspective of their mechanical properties and permeability. The morphology of apical and basal plasma membranes and localisation of Na+/K+-ATPase are compared with other arthropod-transporting epithelia according to different functions of the anterior chamber and the papillate region.
Ključne besede: cell junctions, digestive system, extracellular matrix, ion transporting epithelium, plasma membrane labyrinth
Objavljeno v DiRROS: 24.07.2024; Ogledov: 216; Prenosov: 153
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2. Nanoscale transformations of amphiboles within human alveolar epithelial cellsRuggero Vigliaturo, Maja Jamnik, Goran Dražić, Marjetka Podobnik, Magda Tušek-Žnidarič, Giancarlo Della Ventura, Günther Redhammer, Nada Žnidaršič, Simon Caserman, Reto Gieré, 2022, izvirni znanstveni članek Povzetek: Amphibole asbestos is related to lung fibrosis and several types of lung tumors. The disease-triggering mechanisms still challenge our diagnostic capabilities and are still far from being fully understood. The literature focuses primarily on the role and formation of asbestos bodies in lung tissues, but there is a distinct lack of studies on amphibole particles that have been internalized by alveolar epithelial cells (AECs). These internalized particles may directly interact with the cell nucleus and the organelles, exerting a synergistic action with asbestos bodies (AB) from a different location. Here we document the near-atomic- to nano-scale transformations induced by, and taking place within, AECs of three distinct amphiboles (anthophyllite, grunerite, “amosite”) with different Fe-content and morphologic features. We show that: (i) an Fe-rich layer is formed on the internalized particles, (ii) particle grain boundaries are transformed abiotically by the internal chemical environment of AECs and/or by a biologically induced mineralization mechanism, (iii) the Fe-rich material produced on the particle surface does not contain large amounts of P, in stark contrast to extracellular ABs, and (iv) the iron in the Fe-rich layer is derived from the particle itself. Internalized particles and ABs follow two distinct formation mechanisms reaching different physicochemical end-states.
Ključne besede: amphiboles, human alveolar epithelial cells, asbestos, lung cancer, nanoscale investigation, acS/TEM-EDXS, dual-EELS, asbestos-related tumors
Objavljeno v DiRROS: 16.07.2024; Ogledov: 329; Prenosov: 178
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3. Leafhopper males compensate for unclear directional cues in vibration-mediated mate localizationJernej Polajnar, Ana Kuhelj, Rok Janža, Nada Žnidaršič, Tatjana Simčič, Meta Virant-Doberlet, 2023, izvirni znanstveni članek Povzetek: Ambient noise and transmission properties of the substrate pose challenges in vibrational signal-mediated mating behavior of arthropods, because vibrational signal production is energetically demanding. We explored implications of these challenges in the leafhopper Aphrodes makarovi (Insecta: Hemiptera: Cicadellidae) by exposing males to various kinds of vibrational noise on a natural substrate and challenging them to find the source of the female playback. Contrary to expectations, males exposed to noise were at least as efficient as control males on account of similar searching success with less signaling effort, while playing back male–female duets allowed the males to switch to satellite behavior and locate the target without signaling, as expected. We found altered mitochondrial structure in males with high signaling effort that likely indicate early damaging processes at the cellular level in tymbal muscle, but no relation between biochemical markers of oxidative stress and signaling effort. Analysis of signal transmission revealed ambiguous amplitude gradients, which might explain relatively low searching success, but it also indicates the existence of behavioral adaptations to complex vibrational environments. We conclude that the observed searching tactic, emphasizing speed rather than thorough evaluation of directional cues, may compensate for unclear stimuli when the target is near.
Ključne besede: biotremology, vibrational communication, sexual behavior of insects, impact of noise on behavior, metabolism of vibrational production
Objavljeno v DiRROS: 12.07.2024; Ogledov: 211; Prenosov: 211
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4. Pore-forming moss protein bryoporin is structurally and mechanistically related to actinoporins from evolutionarily distant cnidariansGašper Šolinc, Tomaž Švigelj, Neža Omersa, Tina Snoj, Katja Pirc, Nada Žnidaršič, Akiko Yamaji-Hasegawa, Toshihide Kobayashi, Gregor Anderluh, Marjetka Podobnik, 2022, izvirni znanstveni članek Objavljeno v DiRROS: 11.10.2022; Ogledov: 779; Prenosov: 528
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5. Ectomycorrhiza between Scleroderma Areolatum Ehrenb. and Fagus sylvatica L.Tanja Mrak, Katja Kühdorf, Tine Grebenc, Ines Štraus, Marko Bajc, Nada Žnidaršič, Babette Münzenberger, Hojka Kraigher, 2015, objavljeni povzetek znanstvenega prispevka na konferenci Objavljeno v DiRROS: 03.11.2021; Ogledov: 1154; Prenosov: 391
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