efflux pumps Dotaz Zobrazit nápovědu
Efluxní pumpy, které jsou schopny odčerpávat z bakteriální buňky aktivně antibiotika, můžeme jmenovat jako jeden z možných mechanizmů vzniku antimikrobiální rezistence. Mezi nejvýznamnější skupinu efluxních pump, schopných vyplavovat i více typů antibiotik, řadíme RND (resistance - nodulation - division) pumpy. Jedná se o tři na sebe navazující proteiny, procházející napříč buněčnou stěnou bakterie, umožňující vypuzení látky přímo ven z bakteriální buňky. Nejvíce prostudovanými jsou efluxní pumpy AcrAB-TolC u Escherichia coli a MexAB-OprM u Pseudomonas aeruginosa. Efluxní pumpy jsou schopny odčerpávat i jiné než antibakteriální látky, např. dezinfekční prostředky, čímž snižují jejich účinek. Jednou z možností, jak efluxní pumpy inaktivovat, je použiti tzv. inhibitorů efluxních pump (efflux pump inhibitor = EPI). Mezi potenciální inhibitory testované in vitro můžeme řadit např. phenylalanyl arginyl β-naphtylamide (PAβN), carbonyl cyanide m-chlorophenylhydrazone (CCCP) nebo látky z řad fenothiazinů.
Efflux pumps capable of actively draining antibiotic agents from bacterial cells may be considered one of potential mechanisms of the development of antimicrobial resistance. The most important group of efflux pumps capable of removing several types of antibiotics include RND (resistance - nodulation - division) pumps. These are three proteins that cross the bacterial cell wall, allowing direct expulsion of the agent out from the bacterial cell. The most investigated efflux pumps are the AcrAB-TolC system in Escherichia coli and the MexAB-OprM system in Pseudomonas aeruginosa. Moreover, efflux pumps are able to export other than antibacterial agents such as disinfectants, thus decreasing their effectiveness. One potential approach to inactivation of an efflux pump is to use the so-called efflux pump inhibitors (EPIs). Potential inhibitors tested in vitro involve, for example, phenylalanyl-arginyl-β-naphthylamide (PAβN), carbonyl cyanide m-chlorophenylhydrazone (CCCP) or agents of the phenothiazine class.
- Klíčová slova
- inhibitory efluxních pump,
- MeSH
- aktivní transport fyziologie účinky léků MeSH
- antibakteriální látky * farmakologie MeSH
- Bacteria účinky léků MeSH
- bakteriální léková rezistence * fyziologie MeSH
- bakteriální proteiny * antagonisté a inhibitory fyziologie metabolismus MeSH
- beta-laktamasy farmakologie MeSH
- buněčná membrána metabolismus MeSH
- dezinficiencia farmakologie MeSH
- fluorochinolony farmakologie MeSH
- lidé MeSH
- membránové proteiny * fyziologie metabolismus MeSH
- membránové transportní proteiny fyziologie MeSH
- proteiny vnější bakteriální membrány fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Rezistence na antibiotika je v současnosti problém, který ovlivňuje pacienty, lékaře, mikrobiology i širší zdravotnickou obec. Zahrnuje jak hospitalizované pacienty, tak ty, kteří jsou léčeni mimo nemocniční zařízení. Z lékařů problematika zasahuje do činnosti jak chirurgů, tak ostatních specialistů. Širší zdravotnická obec je pak zasažena uzavíráním lůžkových kapacit, zvýšením finančních nákladů a následnými důsledky ve fungování zdravotnického systému při vypuknutí epidemií. Řešení problematiky rezistence na antibiotika je často ztěžováno praktickou potřebou lékařů léčit pacienty právě těmi antibiotiky, které problém zhoršují.
Antibiotic resistance is a contemporary problem affecting patients, doctors, microbiologists and the wider medical community. The patients include both those who are hospitalised and those treated in the community. The doctors include physicians and surgeons alike. The wider medical community is affected by outbreaks, bed closures, costs and a far-reaching impact on the efficient functioning of the healthcare system. Solutions to the problem of antibiotic resistance are often at odds with the practical need for doctors to treat patients with the very antibiotics which are fuelling the problem.
- MeSH
- Acinetobacter baumannii genetika imunologie účinky léků MeSH
- léková rezistence genetika imunologie účinky léků MeSH
- lidé MeSH
- membránové transportní proteiny genetika účinky léků MeSH
- minocyklin terapeutické užití MeSH
- Pseudomonas aeruginosa genetika imunologie účinky léků MeSH
- Check Tag
- lidé MeSH
Aim: This work studied the impact of the quorum-sensing molecule, farnesol (FAR), on fluconazole (FLC)-resistant Candida albicans isolate CY 1123 compared with the susceptible standard strain C. albicans SC5314. The genes encoding efflux pumps belonging to the ATP-binding cassette (ABC) and major facilitator superfamilies, together with overexpression or point mutation of the ERG11 gene, are the main resistance mechanisms to azole antifungal drugs. Results: The upregulation of genes coding for CDR1, CDR2, and MDR1 were confirmed by qPCR with respect to the housekeeping gene ACT1 in the resistant strain. The contribution of the ERG11 gene was also observed. Markedly, increased pump activity (Cdr1 and/or Cdr2) in the CY 1123 strain was confirmed using diS-C3(3) assay. However, the addition of FAR to the yeasts diminished the difference in staining levels between the SC5314 and CY 1123 strains, demonstrating the concentration-dependent character that could be caused by an effective modulation of Cdr pumps. FAR (60 and 100 μM) was also able to decrease the minimal inhibitory concentrations (MIC50), denoting the inhibition of planktonic cells by 50%, from 8 to 4 μg/mL of FLC when the resistant strain CY 1123 was not cultivated with FLC. However, when it was exposed to 64 μg/mL of FLC, the MIC50 shifted from 64 to 8 μg/mL. Conclusion: Besides the many other effects of FAR on eukaryotic and prokaryotic cells, it also affects ABC efflux transporters, resulting in changes in resistance to azoles in C. albicans isolates. However, this effect is dependent on FAR concentrations.
- MeSH
- ABC transportéry metabolismus MeSH
- antifungální látky farmakologie MeSH
- biologický transport účinky léků MeSH
- Candida albicans účinky léků metabolismus MeSH
- farnesol farmakologie MeSH
- flukonazol farmakologie MeSH
- fungální léková rezistence účinky léků MeSH
- fungální proteiny metabolismus MeSH
- membránové transportní proteiny metabolismus MeSH
- mikrobiální testy citlivosti metody MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: Resistance of pathogenic strains of Escherichia coli to β-lactams, particularly to ampicillin, is on the rise and it is attributed to intrinsic and acquired mechanisms. One important factor contributing to resistance, together with primarily resistance mechanisms, is a mutation and/or an over-expression of the intrinsic efflux pumps in the resistance-nodulation-division (RND) superfamily. Among these efflux pumps, AcrA, AcrB, TolC, and AcrD play an important role in antimicrobial co-resistance, including resistance to β-lactams. MATERIALS AND METHODS: Twelve E. coli isolates obtained from patients' wounds and the control strain of E. coli ATCC 25922 were analyzed. The phenotypic resistance of these isolates to selected β-lactams was assessed by determination of the minimal inhibitory concentration. Additionally, the prevalence of β-lactamase genes (blaTEM, blaCTX-M, blaSHV, and blaAmpC) was screened by PCR. Real-time qPCR was used to determine the expression of the selected efflux pumps acrA, acrB, tolC, and acrD and the repressor acrR after the exposure of E. coli to ampicillin. RESULTS: Phenotypic resistance to β-lactams was detected in seven isolates, mainly to ampicillin and piperacillin. This was corroborated by the presence of at least one acquired bla gene in each of these isolates. Although E. coli strains varied in the expression of RND-family efflux pumps after the ampicillin exposure, their gene expression indicated that these pumps did not play a major role in the phenotypic resistance to ampicillin. CONCLUSION: Each E. coli isolate displayed unique characteristics, differing in minimum inhibitory concentration (MIC) values, prevalence of acquired blaTEM and blaCTX-M genes, and expression of the RND-family pumps. This together demonstrates that these clinical isolates employed distinct intrinsic or acquired resistance pathways for their defense against ampicillin. The prevalence and spread of ampicillin resistant E. coli has to be monitored and the search for ampicillin alternatives is needed.
- Publikační typ
- časopisecké články MeSH
Drug resistance has now become a serious concern in the domain of microbial infection. Bacteria are becoming smarter by displaying a variety of mechanisms during drug resistance. It is not only helping bacteria to adapt nicely in adverse environment but it also makes a smart system for better availability of nutritional status for microorganisms. In this domain, pathogenic bacteria are extensively studied and their mechanism for drug resistance is well explored. The common modes in bacterial resistance include degradation of antibiotics by enzymes, antibiotic target modification or inactivation by enzymatic actions, complete replacement of antibiotic targets, quorum sensing (QS) mechanism, and efflux pump-based extrusion of antibiotics. In this review, various mechanisms of drug resistance in bacteria have been highlighted with giving the importance of efflux pumps. This can be explored as a knowledge source for the management of a variety of bacterial infections, related disease and vibrant clue for next-generation drug development.
N-butanol, a valued solvent and potential fuel extender, could possibly be produced by fermentation using either native producers, i.e. solventogenic Clostridia, or engineered platform organisms such as Escherichia coli or Pseudomonas species, if the main process obstacle, a low final butanol concentration, could be overcome. A low final concentration of butanol is the result of its high toxicity to production cells. Nevertheless, bacteria have developed several mechanisms to cope with this toxicity and one of them is active butanol efflux. This review presents information about a few well characterized butanol efflux pumps from Gram-negative bacteria (P. putida and E. coli) and summarizes knowledge about putative butanol efflux systems in Gram-positive bacteria.
- MeSH
- bakteriální proteiny MeSH
- biologický transport MeSH
- Escherichia coli * MeSH
- membránové transportní proteiny MeSH
- metabolické inženýrství MeSH
- mikrobiální viabilita MeSH
- n-butanol * analýza metabolismus toxicita MeSH
- proteiny z Escherichia coli MeSH
- Pseudomonas putida * MeSH
- rozpouštědla MeSH
- transportní proteiny MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Much like other microorganisms, wild yeasts preferentially form surface-associated communities, such as biofilms and colonies, that are well protected against hostile environments and, when growing as pathogens, against the host immune system. However, the molecular mechanisms underlying the spatiotemporal development and environmental resistance of biofilms and colonies remain largely unknown. In this paper, we show that a biofilm yeast colony is a finely tuned, complex multicellular organism in which specialized cells jointly execute multiple protection strategies. These include a Pdr1p-regulated mechanism whereby multidrug resistance transporters Pdr5p and Snq2p expel external compounds solely within the surface cell layers as well as developmentally regulated production by internal cells of a selectively permeable extracellular matrix. The two mechanisms act in concert during colony development, allowing growth of new cell generations in a well-protected internal cavity of the colony. Colony architecture is strengthened by intercellular fiber connections.
- MeSH
- ABC transportéry genetika metabolismus MeSH
- biofilmy růst a vývoj MeSH
- biologické modely MeSH
- delece genu MeSH
- DNA vazebné proteiny genetika metabolismus MeSH
- extracelulární matrix fyziologie MeSH
- galaktokinasa genetika metabolismus MeSH
- galaktosa metabolismus MeSH
- hydroxymethylglutaryl-CoA-reduktasy genetika metabolismus MeSH
- měď metabolismus MeSH
- membránové glykoproteiny genetika metabolismus MeSH
- metalothionein genetika metabolismus MeSH
- oxaziny metabolismus MeSH
- permeabilita MeSH
- profiliny genetika MeSH
- proteiny buněčného cyklu genetika MeSH
- proteiny spojené s mnohočetnou rezistencí k lékům genetika metabolismus MeSH
- rekombinantní fúzní proteiny genetika metabolismus MeSH
- Saccharomyces cerevisiae - proteiny genetika metabolismus MeSH
- Saccharomyces cerevisiae cytologie růst a vývoj metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- zelené fluorescenční proteiny genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.
- MeSH
- aceton MeSH
- butanoly MeSH
- Clostridium beijerinckii * MeSH
- Clostridium MeSH
- ethanol MeSH
- fermentace MeSH
- Publikační typ
- časopisecké články MeSH
Intercellular flow of the phytohormone auxin underpins multiple developmental processes in plants. Plant-specific pin-formed (PIN) proteins and several phosphoglycoprotein (PGP) transporters are crucial factors in auxin transport-related development, yet the molecular function of PINs remains unknown. Here, we show that PINs mediate auxin efflux from mammalian and yeast cells without needing additional plant-specific factors. Conditional gain-of-function alleles and quantitative measurements of auxin accumulation in Arabidopsis and tobacco cultured cells revealed that the action of PINs in auxin efflux is distinct from PGP, rate-limiting, specific to auxins, and sensitive to auxin transport inhibitors. This suggests a direct involvement of PINs in catalyzing cellular auxin efflux.
- MeSH
- ABC transportéry genetika metabolismus MeSH
- Arabidopsis cytologie fyziologie metabolismus růst a vývoj MeSH
- biologický transport MeSH
- buněčná membrána metabolismus MeSH
- financování organizované MeSH
- ftalimidy farmakologie MeSH
- gravitropismus MeSH
- HeLa buňky MeSH
- kinetika MeSH
- kořeny rostlin fyziologie MeSH
- kultivované buňky MeSH
- kyseliny indoloctové metabolismus MeSH
- kyseliny naftalenoctové metabolismus MeSH
- lidé MeSH
- membránové transportní proteiny genetika metabolismus MeSH
- mutace MeSH
- proteiny huseníčku genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika MeSH
- tabák MeSH
- transfekce MeSH
- transformace genetická MeSH
- Check Tag
- lidé MeSH
