Surfactin, an anionic lipopeptide produced by Bacillus subtilis, is an antimicrobial that targets the cytoplasmic membrane. Nowadays it appears increasingly apparent that the mechanism of resistance against these types of antibiotics consists of target site modification. This prompted us to investigate whether the surfactin non-producing strain B. subtilis 168 changes its membrane composition in response to a sublethal surfactin concentration. Here we show that the exposure of B. subtilis to surfactin at concentrations of 350 and 650 μg/ml (designated as SF350 and SF650, respectively) leads to a concentration-dependent growth arrest followed by regrowth with an altered growth rate. Analysis of the membrane lipid composition revealed modifications both in the polar head group and the fatty acid region. The presence of either surfactin concentration resulted in a reduction in the content of the major membrane phospholipid phosphatidylglycerol (PG) and increase in phosphatidylethanolamine (PE), which was accompanied by elevated levels of phosphatidic acid (PA) in SF350 cultures. The fatty acid analysis of SF350 cells showed a marked increase in non-branched high-melting fatty acids, which lowered the fluidity of the membrane interior measured as the steady-state fluorescence anisotropy of DPH. The liposome leakage of carboxyfluorescein-loaded vesicles resembling the phospholipid composition of surfactin-adapted cells showed that the susceptibility to surfactin-induced leakage is strongly reduced when the PG/PE ratio decreases and/or PA is included in the target bilayer. We concluded that the modifications of the phospholipid content of B. subtilis cells might provide a self-tolerance of the membrane active surfactin.
- MeSH
- Bacillus subtilis chemie účinky léků růst a vývoj MeSH
- cyklické peptidy farmakologie MeSH
- fluidita membrány účinky léků MeSH
- fosfolipidy analýza MeSH
- lipopeptidy farmakologie MeSH
- mastné kyseliny analýza MeSH
- membránové lipidy analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Sequence variability in the hepatitis C virus (HCV) genome has led to the development and classification of six genotypes and a number of subtypes. The HCV 5' untranslated region mainly comprises an internal ribosomal entry site (IRES) responsible for cap-independent synthesis of the viral polyprotein and is conserved among all HCV genotypes. DESCRIPTION: Considering the possible high impact of variations in HCV IRES on viral protein production and thus virus replication, we decided to collect the available data on known nucleotide variants in the HCV IRES and their impact on IRES function in translation initiation. The HCV IRES variation database (HCVIVdb) is a collection of naturally occurring and engineered mutation entries for the HCV IRES. Each entry contains contextual information pertaining to the entry such as the HCV genotypic background and links to the original publication. Where available, quantitative data on the IRES efficiency in translation have been collated along with details on the reporter system used to generate the data. Data are displayed both in a tabular and graphical formats and allow direct comparison of results from different experiments. Together the data provide a central resource for researchers in the IRES and hepatitis C-oriented fields. CONCLUSION: The collation of over 1900 mutations enables systematic analysis of the HCV IRES. The database is mainly dedicated to detailed comparative and functional analysis of all the HCV IRES domains, which can further lead to the development of site-specific drug designs and provide a guide for future experiments. HCVIVdb is available at http://www.hcvivdb.org .
- MeSH
- 5' nepřekládaná oblast MeSH
- databáze genetické * MeSH
- genotyp MeSH
- Hepacivirus genetika metabolismus MeSH
- hepatitida C virologie MeSH
- IRES genetika MeSH
- lidé MeSH
- mutace MeSH
- proteosyntéza MeSH
- RNA virová genetika MeSH
- sběr dat MeSH
- sekvence nukleotidů MeSH
- virové proteiny biosyntéza genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned.
Contamination of water by heavy metals represents a potential risk for both aquatic and terrestrial organisms, including humans. Heavy metals in water resources can come from various industrial activities, and drinking water can be ex-post contaminated by heavy metals such as Cu(2+) from house fittings (e.g., water reservoirs) and pipes. Here, we present a new copper biosensor capable of detecting copper ions at concentrations of 1-100 μM. This biosensor is based on cells of a specifically modified Saccharomyces cerevisiae strain immobilized in alginate beads. Depending on the concentration of copper, the biosensor beads change color from white, when copper is present in concentrations below the detection limit, to pink or red based on the increase in copper concentration. The biosensor was successfully tested in the determination of copper concentrations in real samples of water contaminated with copper ions. In contrast to analytical methods or other biosensors based on fluorescent proteins, the newly designed biosensor does not require specific equipment and allows the quick detection of copper in many parallel samples.
- MeSH
- biosenzitivní techniky metody MeSH
- chemické látky znečišťující vodu analýza metabolismus MeSH
- genetické inženýrství MeSH
- imobilizované buňky metabolismus MeSH
- kolorimetrie metody MeSH
- limita detekce MeSH
- měď analýza metabolismus MeSH
- odpadní voda analýza MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- voda analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mouse polyomavirus (MPyV) is considered a potential tool for the application of gene therapy; however, the current knowledge of the encapsulation of DNA into virions is vague. We used a series of assays based on the encapsidation of a reporter vector into MPyV pseudovirions to identify putative cis-acting elements that are involved in DNA encapsidation. None of the sequences that were derived from MPyV have been shown to solely enhance the encapsidation of a reporter vector in the assay. The frequency of encapsidation strongly correlated with the total intracellular amount of the vector after transfection. The encapsidation of target DNA into the pseudovirions was shown to be non-specific, and the packaging of non-replicated DNA was observed. We propose that the actual concentration of target DNA at the sites of virion formation is the primary factor that determines its selection for encapsidation.
- MeSH
- buněčné linie MeSH
- genetická terapie přístrojové vybavení MeSH
- genetické vektory genetika fyziologie MeSH
- kapsida metabolismus MeSH
- lidé MeSH
- myši MeSH
- Polyomavirus genetika fyziologie MeSH
- reportérové geny MeSH
- sestavení viru * MeSH
- virion genetika fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Saccharomyces cerevisiae strains isolated from natural settings form structured biofilm colonies that are equipped with intricate protective mechanisms. These wild strains are able to reprogram themselves with a certain frequency during cultivation in plentiful laboratory conditions. The resulting domesticated strains switch off certain protective mechanisms and form smooth colonies that resemble those of common laboratory strains. RESULTS: Here, we show that domestication can be reversed when a domesticated strain is challenged by various adverse conditions; the resulting feral strain restores its ability to form structured biofilm colonies. Phenotypic, microscopic and transcriptomic analyses show that phenotypic transition is a complex process that affects various aspects of feral strain physiology; it leads to a phenotype that resembles the original wild strain in some aspects and the domesticated derivative in others. We specify the genetic determinants that are likely involved in the formation of a structured biofilm colonies. In addition to FLO11, these determinants include genes that affect the cell wall and membrane composition. We also identify changes occurring during phenotypic transitions that affect other properties of phenotypic strain-variants, such as resistance to the impact of environmental stress. Here we document the regulatory role of the histone deacetylase Hda1p in developing such a resistance. CONCLUSIONS: We provide detailed analysis of transcriptomic and phenotypic modulations of three related S. cerevisiae strains that arose by phenotypic switching under diverse environmental conditions. We identify changes specifically related to a strain's ability to create complex structured colonies; we also show that other changes, such as genome rearrangement(s), are unrelated to this ability. Finally, we identify the importance of histone deacetylase Hda1p in strain resistance to stresses.
- MeSH
- biofilmy MeSH
- fenotyp MeSH
- genom fungální MeSH
- glykoproteiny genetika metabolismus MeSH
- histondeacetylasy genetika metabolismus MeSH
- membránové glykoproteiny genetika metabolismus MeSH
- regulace genové exprese u hub MeSH
- Saccharomyces cerevisiae - proteiny genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika fyziologie ultrastruktura MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Human immunodeficiency virus-1 (HIV-1) successfully escapes from host immune surveillance, vaccines and antiretroviral agents. The available antiretroviral compounds can only control viremia, but it is impossible to eliminate the virus from the organism, namely because HIV-1 provirus persists in the reservoir cells from which the virus repeatedly disseminates into new cells. Current therapeutic approaches, however, do not specifically address the stage of virus reactivation. Heme has been demonstrated as very efficient in inhibiting HIV-1 reverse transcription, while its derivative hemin ameliorated HIV-1 infection via induction of heme oxygenase-1. Normosang (heme arginate; HA) is a human hemin-containing compound used to treat acute porphyria. In this work, we studied the effects of HA in HIV-1-acutely infected T-cell lines, and in cell lines harboring either a complete HIV-1 provirus (ACH-2 cells) or an HIV-1 "mini-virus" (Jurkat clones expressing EGFP under control of HIV LTR). We demonstrate that HA inhibited HIV-1 replication during the acute infection, which was accompanied by the inhibition of reverse transcription. On the other hand, HA alone stimulated the reactivation of HIV-1 "mini-virus" and synergized with phorbol ester or TNF-α in the reactivation of HIV-1 provirus. The stimulatory effects of HA were inhibited by N-acetyl cysteine, suggesting an increased redox stress and activation of NF-κB. Further, HA induced expression of heme oxygenase-1 (HO-1) in ACH-2 cells, while HO-1 was found expressed in untreated Jurkat clones. Inhibitor of HO-1 activity, tin protoporphyrin IX, further increased HA-mediated reactivation of HIV-1 "mini-virus" in Jurkat clones, and this effect was also inhibited by N-acetyl cysteine. The stimulatory effects of HA on HIV-1 reactivation thus seem to involve HO-1 and generation of free radicals. Additionally, the effective concentrations of HA did neither affect normal T-cell activation with PMA nor induce activation of the unstimulated cells. In conclusion, HA appears to possess a combination of unique properties that could help to decrease the pool of latently infected reservoir cells, while simultaneously inhibiting HIV-1 replication in newly infected cells. Our results thus suggest a new direction to explore in treatment of HIV/AIDS disease.
- MeSH
- acetylcystein farmakologie MeSH
- aktivace viru účinky léků MeSH
- arginin farmakologie MeSH
- buněčné linie MeSH
- CD antigeny metabolismus MeSH
- diferenciační antigeny T-lymfocytů metabolismus MeSH
- hem farmakologie MeSH
- hemoxygenasa-1 antagonisté a inhibitory metabolismus MeSH
- HIV-1 účinky léků fyziologie MeSH
- Jurkat buňky MeSH
- latence viru účinky léků MeSH
- látky proti HIV farmakologie MeSH
- lektiny typu C metabolismus MeSH
- lidé MeSH
- metaloporfyriny farmakologie MeSH
- protoporfyriny farmakologie MeSH
- proviry účinky léků genetika MeSH
- replikace viru účinky léků MeSH
- reverzní transkripce účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Morphogenesis of the mouse polyomavirus virion is a complex and not yet well understood process. Nuclear lysates of infected cells and cells transiently producing the major capsid protein (VP1) of the mouse polyomavirus and whole-cell lysates were separated by blue native polyacrylamide gel electrophoresis (BN-PAGE) to characterize the participation of cellular proteins in virion precursor complexes. Several VP1-specific complexes were found by immunostaining with the anti-VP1 antibody. Some of these complexes contained proteins from the heat shock protein 70 family. The BN-PAGE was found to be a useful tool for the identification of protein complexes by immunostaining of separated cell lysates. However, whole-cell lysates and lysates of isolated nuclei of cells infected with polyomavirus appeared to be too complex for BN-PAGE separation followed by mass spectrometry. No distinct bands specific for cells infected with polyomavirus were detected by Coomassie blue stained gels, hence this method is not suitable for the discovery of new cellular proteins participating in virion assembly. Nevertheless, BN-PAGE can be valuable for the analyses of different types of complexes formed by proteins after their enrichment or isolation by affinity chromatography.
- MeSH
- chromatografie afinitní MeSH
- elektroforéza v polyakrylamidovém gelu metody MeSH
- hmotnostní spektrometrie MeSH
- interakce hostitele a patogenu MeSH
- mapování interakce mezi proteiny MeSH
- myši MeSH
- Polyomavirus chemie patogenita MeSH
- proteom analýza MeSH
- vazba proteinů MeSH
- virové plášťové proteiny metabolismus MeSH
- virové proteiny analýza MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
