Tailocins are nano-scale phage tail-like protein complexes that can mediate antagonistic interactions between closely related bacterial species. While the capacity to produce R-type tailocin was found widely across Gammaproteobacteria, the production of F-type tailocins seems comparatively rare. In this study, we examined the freshwater isolate, Pragia fontium 24613, which can produce both R- and F-type tailocins. We investigated their inhibition spectrum, focusing on clinically relevant enterobacteria, and identified the associated tailocin gene cluster. Transmission electron microscopy confirmed that inactivation of the tape measure protein within the tailocin cluster disrupted R-tailocin production. Comparative analysis of Budviciaceae gene clusters showed high conservation of R-type tailocin genes, whereas F-type tailocin genes were found in only a few species, with little conservation. Our findings indicate a high prevalence of bacteriocin production among underexplored Enterobacteriales species. Detected tailocins showed potential as antimicrobials targeting clinically significant pathogens.
G protein-coupled receptors (GPCRs) play a crucial role in cell function by transducing signals from the extracellular environment to the inside of the cell. They mediate the effects of various stimuli, including hormones, neurotransmitters, ions, photons, food tastants and odorants, and are renowned drug targets. Advancements in structural biology techniques, including X-ray crystallography and cryo-electron microscopy (cryo-EM), have driven the elucidation of an increasing number of GPCR structures. These structures reveal novel features that shed light on receptor activation, dimerization and oligomerization, dichotomy between orthosteric and allosteric modulation, and the intricate interactions underlying signal transduction, providing insights into diverse ligand-binding modes and signalling pathways. However, a substantial portion of the GPCR repertoire and their activation states remain structurally unexplored. Future efforts should prioritize capturing the full structural diversity of GPCRs across multiple dimensions. To do so, the integration of structural biology with biophysical and computational techniques will be essential. We describe in this review the progress of nuclear magnetic resonance (NMR) to examine GPCR plasticity and conformational dynamics, of atomic force microscopy (AFM) to explore the spatial-temporal dynamics and kinetic aspects of GPCRs, and the recent breakthroughs in artificial intelligence for protein structure prediction to characterize the structures of the entire GPCRome. In summary, the journey through GPCR structural biology provided in this review illustrates how far we have come in decoding these essential proteins architecture and function. Looking ahead, integrating cutting-edge biophysics and computational tools offers a path to navigating the GPCR structural landscape, ultimately advancing GPCR-based applications. LINKED ARTICLES: This article is part of a themed issue Complexity of GPCR Modulation and Signaling (ERNST). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.14/issuetoc.
- MeSH
- Protein Conformation MeSH
- Humans MeSH
- Receptors, G-Protein-Coupled * chemistry metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
OBJECTIVES: This study aimed to investigate the impact of bleaching agents based on carbamide or hydrogen peroxide on dental ceramics in vitro, utilizing scanning electron microscopy (SEM) and elemental analysis via inductively coupled plasma optical emission spectroscopy (ICP-OES). METHODS: CAD/CAM ceramics (IPS e.max®CAD, IPS Empress®CAD, Vitablocs® Mark II, Celtra Duo, and inCoris TZI) were treated with bleaching agents using either 10%, 20%, 30% carbamide peroxide or with 35%, and 40% hydrogen peroxide. RESULTS: Surface elemental release was not significantly affected by the type or concentration of bleaching agent (p>0.05). Ion release in feldspathic ceramics was significantly higher than in other ceramic materials (p⟨0.0001). Microstructural surface changes were observed in all materials except for lithium disilicate and zirconia-reinforced lithium silicate ceramics. CONCLUSIONS: All bleaching agents tested in this study showed a similar impact within each material type tested regarding total mass loss, elemental composition, or surface structure. CLINICAL RELEVANCE: Lithium disilicate and zirconia-reinforced lithium silicate ceramics were the most resistant to bleaching agents. In contrast, feldspathic ceramic showed the highest ion release and surface deterioration when exposed to all bleaching agents tested.
- MeSH
- Computer-Aided Design * MeSH
- Carbamide Peroxide * chemistry MeSH
- Ceramics * chemistry MeSH
- Tooth Bleaching Agents * chemistry MeSH
- Microscopy, Electron, Scanning MeSH
- Hydrogen Peroxide * chemistry MeSH
- Surface Properties MeSH
- Materials Testing MeSH
- Zirconium chemistry MeSH
- Dental Porcelain * chemistry MeSH
- Publication type
- Journal Article MeSH
In the presented study, the cells of the glacial alga Ancylonema alaskanum collected in the Austrian Alps were analyzed. Algae were imaged both in their natural environment and in laboratory conditions using transmitted light and fluorescence microscopy. Using appropriate fluorochromes, the cell wall and cell organelles were studied. Oval nuclei located in the middle of the cell next to the chloroplasts and active mitochondria as well as lipid thylakoids of chloroplasts were imaged. Scanning electron microscopy showed that the surface of the algal cell wall was not significantly differentiated, and atomic force microscope imaging recorded little roughness. The SEM EDS analysis revealed that carbon, nitrogen, oxygen, and magnesium were the main components of the cells. It is worth emphasizing that the analyzed living algal cells were obtained directly from the glacier surface and demonstrated normal respiratory processes i.e. undisturbed physiological functions. Additionally, the mineral material accompanying the cells in their natural environment - fragments of the rock were imaged by Differential Interference Contrast microscopy and analyzed by Fourier Transform Infrared Spectroscopy. The study provides new data on the morphology and physicochemical characteristics of A. alaskanum, contributing to a more comprehensive characterization of their place in this harsh ecosystem.
- MeSH
- Ice Cover * MeSH
- Microscopy, Electron, Scanning MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Austria MeSH
Nedd4-2 E3 ligase regulates Na+ homeostasis by ubiquitinating various channels and membrane transporters, including the epithelial sodium channel ENaC. In turn, Nedd4-2 dysregulation leads to various conditions, including electrolytic imbalance, respiratory distress, hypertension, and kidney diseases. However, Nedd4-2 regulation remains mostly unclear. The present study aims at elucidating Nedd4-2 regulation by structurally characterizing Nedd4-2 and its complexes using several biophysical techniques. Our cryo-EM reconstruction shows that the C2 domain blocks the E2-binding surface of the HECT domain. This blockage, ubiquitin-binding exosite masking by the WW1 domain, catalytic C922 blockage and HECT domain stabilization provide the structural basis for Nedd4-2 autoinhibition. Furthermore, Ca2+-dependent C2 membrane binding disrupts C2/HECT interactions, but not Ca2+ alone, whereas 14-3-3 protein binds to a flexible region of Nedd4-2 containing the WW2 and WW3 domains, thereby inhibiting its catalytic activity and membrane binding. Overall, our data provide key mechanistic insights into Nedd4-2 regulation toward fostering the development of strategies targeting Nedd4-2 function.
- MeSH
- Cryoelectron Microscopy MeSH
- HEK293 Cells MeSH
- Humans MeSH
- Models, Molecular MeSH
- Protein Domains MeSH
- 14-3-3 Proteins * metabolism chemistry MeSH
- Ubiquitination MeSH
- Nedd4 Ubiquitin Protein Ligases * metabolism chemistry genetics ultrastructure MeSH
- Calcium * metabolism MeSH
- Protein Binding MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Many photosensitive substances suitable for photodynamic therapy (PDT) have limited applications due to their insufficient solubility in polar solvents. Our research overcomes this challenge by means of nanotechnology in order to transform hydrophobic compounds into stable aqueous solutions, enabling them to use their full potential and unique properties in cancer therapy. In this study, the novel nano-composite cGQDs-PEG-curcumin was developed to overcome the insolubility of curcumin in water and its extraordinary efficacy in PDT was evaluated. Complex characterization was performed using high-resolution transmission electron microscopy (HR-TEM), FTIR, and UV-Vis spectroscopy. Further analysis involved fluorescence lifetime imaging (FLIM), and its cellular localization was mapped with confocal microscopy. In order to evaluate PDT effectiveness, cells treated with cGQDs-PEG-curcumin were irradiated with 5 J/cm2 of 414 nm light. After irradiation, cell viability assay, scanning electron microscopy (SEM), reactive oxygen species (ROS) detection, comet assay, and γH2AX-based DNA double-strand breaks (DSBs) detection were assessed and revealed a remarkable ability of the nano-composite to induce DNA damage after irradiation without ROS production. Our findings highlight the potential of cGQDs-PEG-curcumin as a cutting-edge PDT agent, capable of disrupting cell membrane and nucleolar integrity and impairing ribosomal synthesis, which is crucial for proliferating tumour cells.
- MeSH
- Cell Nucleolus * drug effects metabolism MeSH
- DNA Breaks, Double-Stranded drug effects MeSH
- Photochemotherapy * methods MeSH
- Photosensitizing Agents * pharmacology MeSH
- Graphite * chemistry pharmacology MeSH
- Curcumin * pharmacology chemistry MeSH
- Quantum Dots * chemistry MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Neoplasms * drug therapy MeSH
- Polyethylene Glycols * chemistry pharmacology MeSH
- DNA Damage * drug effects MeSH
- Reactive Oxygen Species metabolism MeSH
- Cell Survival drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Extracellular vesicles can play an important role in the processes occurring after stem cell transplantation, preventing cell apoptosis, stimulating immunological processes, and promoting the synthesis of extracellular matrix. Human follicular fluid (FF) can be a source of a subpopulation of cells with mesenchymal stem cells (MSCs) properties. Moreover these subpopulations of FF cells can differentiate into osteoblasts. In presented studies flow cytometry of ovarian FF cells confirmed positive expression of MSCs markers such as: CD44, CD90, CD105, CD73 and negative expression of a hematopoietic marker: CD45. The CD90+, CD105+, CD45- cell subpopulation has been obtained during magnetic separation using appropriate antibodies conjugated with microbeads. The extracellular vesicles (EVs) secreted by the cells during osteodifferentiation process differed from those secreted by cells culture in the basal medium. Based on the previous and current electron microscopy research, changes in size, number, and shape would support the notion that released EVs could be crucial to the ovarian FF cell subpopulation differentiation process. Osteogenic differentiation has been confirmed via Alizarin red staining. Therefore, follicular fluid (FF) can be a new source of a cell subpopulation with MSC properties, with the cells capable of differentiating into the osteogenic lineage. EVs could play a key role as mediators in tissue regeneration, especially bone tissue regeneration.
- MeSH
- Cell Differentiation * MeSH
- Extracellular Vesicles * ultrastructure metabolism MeSH
- Follicular Fluid * cytology metabolism MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Mesenchymal Stem Cells * cytology metabolism MeSH
- Osteoblasts cytology metabolism MeSH
- Osteogenesis * MeSH
- Flow Cytometry MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
There is increasing pressure on meat producers worldwide due to the need for higher yields and improved meat quality. This is why anabolic androgenic steroids (AAS) have been widely used in most countries, due to their ability to accelerate animal muscle growth. However, out of concern for their side effects, EU states have banned their use and implemented control mechanisms. But they are reaching their limits, and therefore, it is necessary to look for new ways and investigate the mechanism of action of AAS on muscle tissue. This study replicated the administration of banned AAS (testosterone, nandrolone and their combination) and observed their effect on pig muscle. The pig model was purposely chosen for the study, as no such research has been carried out on this species. At the same time, pork is one of the most consumed meats in Europe. It focused on histological changes in muscle structure, specifically the size of muscle fibres and the number of satellite cells per muscle fibre. Furthermore, ultrastructural changes in muscle fibres, the diameter of myofibrils, the number of myofibrils per area, the distance between myofibrils and the size of sarcomeres were examined. The results using the techniques of histology, fluorescent labelling and transmission electron microscopy showed that, after the application of AAS, there is an increase in the diameter of muscle fibres, an increase in the diameter of myofibrils, a decrease in the number of myofibrils per surface area and, in the case of testosterone, an increase in the distance between myofibrils and an increase in the length of sarcomeres. There was also a significant increase in the number of satellite cells per muscle fibre. The detected statistically significant differences between control and experimental groups provide evidence that selected histological parameters could be additional mechanisms for detecting the presence of AAS in pork meat in the future.
- MeSH
- Anabolic Agents * pharmacology MeSH
- Muscle Fibers, Skeletal * drug effects ultrastructure MeSH
- Muscle, Skeletal drug effects anatomy & histology ultrastructure MeSH
- Myofibrils * drug effects ultrastructure MeSH
- Nandrolone * pharmacology MeSH
- Swine anatomy & histology MeSH
- Sarcomeres drug effects ultrastructure MeSH
- Satellite Cells, Skeletal Muscle drug effects ultrastructure MeSH
- Testosterone * pharmacology MeSH
- Microscopy, Electron, Transmission veterinary MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Pseudomonas aeruginosa can proliferate in immunocompromised individuals, forming biofilms that increase antibiotic resistance. This bacterium poses a significant global health risk due to its resistance to human defenses, antibiotics, and various environmental stresses. The objective of this study was to evaluate the antibacterial, anti-biofilm, and anti-quorum sensing activities of galloylquinic acid compounds (GQAs) extracted from Copaifera lucens leaves against clinical isolates of multidrug-resistant (MDR) P. aeruginosa. We have investigated the optimal concentration of GQAs needed to eradicate preexisting biofilms and manage wound infections caused by P. aeruginosa, in vitro and in vivo. RESULTS: Our results revealed that GQAs exhibited 25-40 mm inhibition zone diameters, with 1-4 μg/mL MIC and 2-16 μg/mL MBC values. GQAs interfered with the planktonic mode of P. aeruginosa isolates, and significantly inhibited their growth in the pre-formed biofilm architecture, with MBIC80 and MBEC80 values of 64 μg/mL and 128 μg/mL, respectively. The anti-biofilm effect was confirmed by fluorescence staining and confocal microscopy which showed a dramatic reduction in the cell viability and the biofilm thickness (62.5%), after exposure to 128 μg/mL of GQAs in particular. The scanning electron micrographs showed that GQAs impaired biofilm and bacterial structures by interfering with the biomass and the exopolysaccharides forming the matrix. GQAs also interfered with virulence factors and bacterial motility, where 128 μg/mL of GQAs significantly (p < 0.05) reduced rhamnolipid, pyocyanin, and the swarming motility of the organism which play a vital role in the biofilm formation. GQAs downregulated 89% of the quorum-sensing genes (lasI and lasR, pqsA and pqsR) involved in the biofilm formation. CONCLUSION: GQAs demonstrate significant promise as novel and potent antibiofilm and antivirulence agents against clinical isolates of MDR P. aeruginosa, with substantial potential to enhance wound healing in biofilm-associated infections. This promising antibacterial action positions GQAs as a superior alternative for the treatment of biofilm-associated wound infections, with substantial potential to improve wound healing and mitigate the impact of persistent bacterial infections. CLINICAL TRIAL NUMBER: not applicable.
- MeSH
- Anti-Bacterial Agents * pharmacology MeSH
- Biofilms * drug effects growth & development MeSH
- Wound Infection * microbiology drug therapy MeSH
- Humans MeSH
- Plant Leaves chemistry MeSH
- Microbial Sensitivity Tests MeSH
- Drug Resistance, Multiple, Bacterial drug effects MeSH
- Mice MeSH
- Pseudomonas Infections * microbiology drug therapy MeSH
- Pseudomonas aeruginosa * drug effects physiology isolation & purification MeSH
- Quorum Sensing * drug effects MeSH
- Plant Extracts pharmacology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
PURPOSE: To document the expression of apical-basal polarity (ABP) determinants in the mouse corneal epithelium (CE) and elucidate the functions of Pard3 in establishment and maintenance of ABP, stratification, homeostasis, and barrier function in the CE. METHODS: Pard3Δ/ΔC mice (Pard3LoxP/LoxP; Aldh3A1-Cre/+) with cornea-specific Pard3 ablation were generated by breeding Aldh3A1-Cre/+ with Pard3LoxP/LoxP mice. The control (Aldh3A1-Cre/+ or Pard3LoxP/LoxP alone) and Pard3Δ/ΔC corneal histology, ocular surface properties, barrier function, and actin cytoskeleton were assessed by Haematoxylin and Eosin staining of paraformaldehyde-fixed, paraffin-embedded tissues, scanning electron microscopy, fluorescein staining, and phalloidin staining, respectively. The expression of specific markers of interest was evaluated by qRT-PCR, immunoblots and immunofluorescent staining. RESULTS: Dynamic changes were observed in the expression and localization of ABP determinants as the CE stratified and matured between post-natal day 5 (PN5) and PN52. Adult Pard3Δ/ΔC CE contained fewer cell layers with rounded basal cells, and loosely adherent superficial cells lacking microplicae. Adult Pard3Δ/ΔC CE also displayed impaired barrier function with decreased expression of tight junction, adherens junction, and desmosome components, disrupted actin cytoskeletal organization, increased proliferation, and upregulation of transcription factors that drive epithelial-mesenchymal transition (EMT). CONCLUSIONS: Disruption of ABP in Pard3Δ/ΔC CE, altered expression of cell junction complex components and disorganized actin cytoskeleton, increased cell proliferation, and upregulated EMT transcription factors suggest that the ABP-determinant Pard3 promotes CE features while suppressing mesenchymal cell fate. Collectively, these results elucidate that Pard3-mediated ABP is essential for CE stratification, homeostasis and barrier function.
- MeSH
- Adaptor Proteins, Signal Transducing * MeSH
- Cytoskeleton * metabolism MeSH
- Homeostasis physiology MeSH
- Microscopy, Electron, Scanning MeSH
- Mice MeSH
- Cell Polarity * physiology MeSH
- Epithelium, Corneal * metabolism ultrastructure MeSH
- Tight Junctions * metabolism physiology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
