Francisella tularensis influences several host molecular/signaling pathways during infection. Ubiquitination and deubiquitination are among the most important regulatory mechanisms and respectively occur through attachment or removal of the ubiquitin molecule. The process is necessary not only to mark molecules for degradation, but also, for example, to the activation of signaling pathways leading to pro-inflammatory host response. Many intracellular pathogens, including Francisella tularensis, have evolved mechanisms of modifying such host immune responses to escape degradation. Here, we describe that F. tularensis interferes with the host's ubiquitination system. We show increased total activity of deubiquitinating enzymes (DUBs) in human macrophages after infection, while confirm reduced enzymatic activities of two specific DUBs (USP10 and UCH-L5), and demonstrate increased activity of USP25. We further reveal the enrichment of these three enzymes in exosomes derived from F. tularensis-infected cells. The obtained results show the regulatory effect on ubiquitination mechanism in macrophages during F. tularensis infection.

• MeSH
• deubikvitinasy metabolismus   MeSH
• Francisella tularensis * MeSH
• gramnegativní bakteriální infekce * metabolismus   MeSH
• lidé MeSH
• makrofágy MeSH
• signální transdukce MeSH
• thiolesterasa ubikvitinu metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Insulin is stored in vivo inside the pancreatic β-cell insulin secretory granules. In vitro studies have led to an assumption that high insulin and Zn2+ concentrations inside the pancreatic β-cell insulin secretory granules should promote insulin crystalline state in the form of Zn2+-stabilized hexamers. Electron microscopic images of thin sections of the pancreatic β-cells often show a dense, regular pattern core, suggesting the presence of insulin crystals. However, the structural features of the storage forms of insulin in native preparations of secretory granules are unknown, because of their small size, fragile character and difficult handling. We isolated and investigated the secretory granules from MIN6 cells under near-native conditions, using cryo-electron microscopic (Cryo-EM) techniques. The analysis of these data from multiple intra-granular crystals revealed two different rhomboidal crystal lattices. The minor lattice has unit cell parameters (a ≃ b ≃ 84.0 Å, c ≃ 35.2 Å), similar to in vitro crystallized human 4Zn2+-insulin hexamer, whereas the largely prevalent unit cell has more than double c-axis (a ≃ b ≃ c ≃ 96.5 Å) that probably corresponds to two or three insulin hexamers in the asymmetric unit. Our experimental data show that insulin can be present in pancreatic MIN6 cell granules in a microcrystalline form, probably consisting of 4Zn2+-hexamers of this hormone.

• MeSH
• beta-buňky * MeSH
• elektronová mikroskopie MeSH
• inzulin MeSH
• Langerhansovy ostrůvky * MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The increasing risk of antibiotic failure in the treatment of Pseudomonas aeruginosa infections is largely related to the production of a wide range of virulence factors. The use of non-thermal plasma (NTP) is a promising alternative to antimicrobial treatment. Nevertheless, there is still a lack of knowledge about the effects of NTP on the virulence factors production. We evaluated the ability of four NTP-affected P. aeruginosa strains to re-form biofilm and produce Las-B elastase, proteases, lipases, haemolysins, gelatinase or pyocyanin. Highly strains-dependent inhibitory activity of NTP against extracellular virulence factors production was observed. Las-B elastase activity was reduced up to 82% after 15-min NTP treatment, protease activity and pyocyanin production by biofilm cells was completely inhibited after 60 min, in contrast to lipases and gelatinase production, which remained unchanged. However, for all strains tested, a notable reduction in biofilm re-development ability was depicted using spinning disc confocal microscopy. In addition, NTP exposure of mature biofilms caused disruption of biofilm cells and their dispersion into the environment, as shown by transmission electron microscopy. This appears to be a key step that could help overcome the high resistance of P. aeruginosa and its eventual elimination, for example in combination with antibiotics still highly effective against planktonic cells.

• MeSH
• antibakteriální látky farmakologie   MeSH
• biofilmy MeSH
• endopeptidasy farmakologie   MeSH
• faktory virulence MeSH
• hemolyziny farmakologie   MeSH
• lidé MeSH
• pankreatická elastasa MeSH
• plankton MeSH
• plazmové plyny * farmakologie   MeSH
• proteasy MeSH
• pseudomonádové infekce * MeSH
• Pseudomonas aeruginosa MeSH
• pyokyanin MeSH
• quorum sensing MeSH
• želatinasy farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Oxidative stress may cause extended tyrosine posttranslational modifications of peptides and proteins. The 3-nitro-L-tyrosine (Nit), which is typically formed, affects protein behavior during neurodegenerative processes, such as Alzheimer's and Parkinson's diseases. Such metabolic products may be conveniently detected at very low concentrations by surface enhanced Raman spectroscopy (SERS). Previously, we have explored the SERS detection of the Nit NO2 bending vibrational bands in a presence of hydrogen chloride (Niederhafner et al., Amino Acids 53:517-532, 2021, ibid). In this article, we describe performance of a new SERS substrate, "pink silver", synthesized photochemically. It provides SERS even without the HCl induction, and the acid further decreases the detection limit about 9 times. Strong SERS bands were observed in the asymmetric (1550-1475 cm-1) and symmetric (1360-1290 cm-1) NO stretching in the NO2 group. The bending vibration was relatively weak, but appeared stronger when HCl was added. The band assignments were supported by density functional theory modeling.

• MeSH
• oxid dusičitý MeSH
• peptidy MeSH
• proteiny MeSH
• Ramanova spektroskopie * metody   MeSH
• stříbro * chemie   MeSH
• Publikační typ
• časopisecké články MeSH

The authors wish to make the following corrections to this paper [...].

• Publikační typ
• tisková chyba MeSH

The emergence of antibiotic resistance in opportunistic pathogens represents a huge problem, the solution for which may be a treatment with a combination of multiple antimicrobial agents. Sodium salt of cobalt bis-dicarbollide (COSAN.Na) is one of the very stable, low-toxic, amphiphilic boron-rich sandwich complex heteroboranes. This compound has a wide range of potential applications in the biological sciences due to its antitumor, anti-HIV-1, antimicrobial and antibiofilm activity. Our study confirmed the ability of COSAN.Na (in the concentration range 0.2-2.48 μg/mL) to enhance tetracycline, erythromycin, and vancomycin action towards Staphylococcus epidermidis planktonic growth with an additive or synergistic effect (e.g., the combination of 1.24 μg/mL COSAN.Na and 6.5 μg/mL TET). The effective inhibitory concentration of antibiotics was reduced up to tenfold most efficiently in the case of tetracycline (from 65 to 6.5 μg/mL). In addition, strong effect of COSAN.Na on disruption of the cell envelopes was determined using propidium iodide uptake measurement and further confirmed by transmission electron microscopy. The combination of amphiphilic COSAN.Na with antibiotics can therefore be considered a promising way to overcome antibiotic resistance in Gram-positive cocci.

• Publikační typ
• časopisecké články MeSH

Fullerene derivatives with hydrophilic substituents have been shown to exhibit a range of biological activities, including antiviral ones. For a long time, the anti-HIV activity of fullerene derivatives was believed to be due to their binding into the hydrophobic pocket of HIV-1 protease, thereby blocking its activity. Recent work, however, brought new evidence of a novel, protease-independent mechanism of fullerene derivatives' action. We studied in more detail the mechanism of the anti-HIV-1 activity of N,N-dimethyl[70]fulleropyrrolidinium iodide fullerene derivatives. By using a combination of in vitro and cell-based approaches, we showed that these C70 derivatives inhibited neither HIV-1 protease nor HIV-1 maturation. Instead, our data indicate effects of fullerene C70 derivatives on viral genomic RNA packaging and HIV-1 cDNA synthesis during reverse transcription-without impairing reverse transcriptase activity though. Molecularly, this could be explained by a strong binding affinity of these fullerene derivatives to HIV-1 nucleocapsid domain, preventing its proper interaction with viral genomic RNA, thereby blocking reverse transcription and HIV-1 infectivity. Moreover, the fullerene derivatives' oxidative activity and fluorescence quenching, which could be one of the reasons for the inconsistency among reported anti-HIV-1 mechanisms, are discussed herein.

• MeSH
• fullereny metabolismus   farmakologie   MeSH
• genom virový účinky léků   MeSH
• genové produkty gag - virus lidské imunodeficience metabolismus   MeSH
• HEK293 buňky MeSH
• HIV-1 účinky léků   genetika   metabolismus   fyziologie   MeSH
• látky proti HIV metabolismus   farmakologie   MeSH
• lidé MeSH
• nukleokapsida - proteiny metabolismus   MeSH
• reverzní transkripce MeSH
• RNA virová metabolismus   MeSH
• svlékání virového obalu účinky léků   MeSH
• vazba proteinů MeSH
• virion metabolismus   MeSH
• zabalení virového genomu účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Insulin is produced and stored inside the pancreatic β-cell secretory granules, where it is assumed to form Zn2+-stabilized oligomers. However, the actual storage forms of this hormone and the impact of zinc ions on insulin production in vivo are not known. Our initial X-ray fluorescence experiment on granules from native Langerhans islets and insulinoma-derived INS-1E cells revealed a considerable difference in the zinc content. This led our further investigation to evaluate the impact of the intra-granular Zn2+ levels on the production and storage of insulin in different model β-cells. Here, we systematically compared zinc and insulin contents in the permanent INS-1E and BRIN-BD11 β-cells and in the native rat pancreatic islets by flow cytometry, confocal microscopy, immunoblotting, specific messenger RNA (mRNA) and total insulin analysis. These studies revealed an impaired insulin production in the permanent β-cell lines with the diminished intracellular zinc content. The drop in insulin and Zn2+ levels was paralleled by a lower expression of ZnT8 zinc transporter mRNA and hampered proinsulin processing/folding in both permanent cell lines. To summarize, we showed that the disruption of zinc homeostasis in the model β-cells correlated with their impaired insulin and ZnT8 production. This indicates a need for in-depth fundamental research about the role of zinc in insulin production and storage.

• MeSH
• beta-buňky metabolismus   ultrastruktura   MeSH
• chemická frakcionace MeSH
• cytoplazmatická granula metabolismus   MeSH
• exprese genu * MeSH
• glukosa metabolismus   MeSH
• inzulin genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• Langerhansovy ostrůvky metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• průtoková cytometrie metody   MeSH
• zinek metabolismus   MeSH
• zinkový transportér 8 MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tick-borne encephalitis virus (TBEV), a member of flaviviruses, represents a serious health threat by causing human encephalitis mainly in central and eastern Europe, Russia, and northeastern Asia. As no specific therapy is available, there is an urgent need to understand all steps of the TBEV replication cycle at the molecular level. One of the critical events is the packaging of flaviviral genomic RNA by TBEV C protein to form a nucleocapsid. We purified recombinant TBEV C protein and used a combination of physical-chemical approaches, such as size-exclusion chromatography, circular dichroism, NMR spectroscopies, and transmission electron microscopy, to analyze its structural stability and its ability to dimerize/oligomerize. We compared the ability of TBEV C protein to assemble in vitro into a nucleocapsid-like structure with that of dengue C protein.

• MeSH
• cirkulární dichroismus MeSH
• gelová chromatografie MeSH
• koncentrace vodíkových iontů MeSH
• magnetická rezonanční spektroskopie MeSH
• nukleokapsida chemie   metabolismus   MeSH
• rekombinantní proteiny chemie   genetika   izolace a purifikace   MeSH
• virové proteiny chemie   genetika   izolace a purifikace   metabolismus   MeSH
• virus dengue chemie   MeSH
• viry klíšťové encefalitidy chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pathogenic yeasts Candida albicans and Candida parapsilosis possess a ß-type carbonic anhydrase Nce103p, which is involved in CO2 hydration and signaling. C. albicans lacking Nce103p cannot survive in low CO2 concentrations, e.g., in atmospheric growth conditions. Candida carbonic anhydrases are orthologous to the Saccharomyces cerevisiae enzyme, which had originally been detected as a substrate of a non-classical export pathway. However, experimental evidence on localization of C. albicans and C. parapsilosis carbonic anhydrases has not been reported to date. Immunogold labeling and electron microscopy used in the present study showed that carbonic anhydrases are localized in the cell wall and plasmatic membrane of both Candida species. This localization was confirmed by Western blot and mass spectrometry analyses of isolated cell wall and plasma membrane fractions. Further analysis of C. albicans and C. parapsilosis subcellular fractions revealed presence of carbonic anhydrases also in the cytosolic and mitochondrial fractions of Candida cells cultivated in shaken liquid cultures, under the atmospheric conditions.

• MeSH
• buněčná membrána enzymologie   MeSH
• buněčná stěna enzymologie   MeSH
• Candida albicans enzymologie   růst a vývoj   MeSH
• Candida parapsilosis enzymologie   růst a vývoj   MeSH
• cytosol enzymologie   MeSH
• elektronová mikroskopie MeSH
• fungální proteiny metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• karboanhydrasy metabolismus   MeSH
• mitochondrie enzymologie   MeSH
• techniky vsádkové kultivace MeSH
• Publikační typ
• časopisecké články MeSH