scholarly journals Activity and Toxicity of Farnesol towards Candida albicans Are Dependent on Growth Conditions

2009 ◽  
Vol 54 (2) ◽  
pp. 940-942 ◽  
Author(s):  
Melanie L. Langford ◽  
Sahar Hasim ◽  
Kenneth W. Nickerson ◽  
Audrey L. Atkin
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Environmental Conditions ◽  
Growth Conditions ◽  
Growth Media ◽  
Energy Availability ◽  
Toxic Agent ◽  
Temperature And Growth ◽  
New Variables ◽  
Quorum Sensing Molecule

ABSTRACT Farnesol interacts with Candida albicans as both a quorum-sensing molecule and toxic agent, but confusion abounds regarding which conditions promote these distinct responses. Farnesol sensitivity was measured when inoculum cell history and size, temperature, and growth media were altered. Parameters for farnesol tolerance/sensitivity were defined, validating previous studies and identifying new variables, such as energy availability. This study clearly defines what farnesol concentrations are lethal to C. albicans, based on environmental conditions.

Farnesol restores wild-type colony morphology to 96% of Candida albicans colony morphology variants recovered following treatment with mutagens

Genome ◽  
2006 ◽  
Vol 49 (4) ◽  
pp. 346-353 ◽  
Author(s):  
Ellen C Jensen ◽  
Jacob M Hornby ◽  
Nicole E Pagliaccetti ◽  
Chuleeon M Wolter ◽  
Kenneth W Nickerson ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Environmental Conditions ◽  
Budding Yeast ◽  
Colony Morphology ◽  
Morphological Transition ◽  
Strongly Correlated ◽  
Wild Type ◽  
Hyphal Morphology

Candida albicans is a diploid fungus that undergoes a morphological transition between budding yeast, hyphal, and pseudohyphal forms. The morphological transition is strongly correlated with virulence and is regulated in part by quorum sensing. Candida albicans produces and secretes farnesol that regulates the yeast to mycelia morphological transition. Mutants that fail to synthesize or respond to farnesol could be locked in the filamentous mode. To test this hypothesis, a collection of C. albicans mutants were isolated that have altered colony morphologies indicative of the presence of hyphal cells under environmental conditions where C. albicans normally grows only as yeasts. All mutants were characterized for their ability to respond to farnesol. Of these, 95.9% fully or partially reverted to wild-type morphology on yeast malt (YM) agar plates supplemented with farnesol. All mutants that respond to farnesol regained their hyphal morphology when restreaked on YM plates without farnesol. The observation that farnesol remedial mutants are so common (95.9%) relative to mutants that fail to respond to farnesol (4.1%) suggests that farnesol activates and (or) induces a pathway that can override many of the morphogenesis defects in these mutants. Additionally, 9 mutants chosen at random were screened for farnesol production. Two mutants failed to produce detectable levels of farnesol.Key words: farnesol-remedial mutants, farnesol-sensing mutants, farnesol-synthesis mutants, quorum sensing, Candida albicans, morphological transition.

scholarly journals Environmental Regulation of Pseudomonas aeruginosa PAO1 Las and Rhl Quorum-Sensing Systems

2007 ◽  
Vol 189 (13) ◽  
pp. 4827-4836 ◽  
Author(s):  
Kangmin Duan ◽  
Michael G. Surette
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Environmental Conditions ◽  
Transcriptional Regulator ◽  
Transcriptional Regulators ◽  
Growth Conditions ◽  
Fine Tuning ◽  
Relative Timing ◽  
Sensing Systems ◽  
Two Systems

ABSTRACT The lasI-lasR and the rhlI-rhlR quorum-sensing systems in Pseudomonas aeruginosa regulate the expression of numerous cellular and secreted virulence factor genes and play important roles in the development of biofilms. The las and rhl systems themselves are known to be directly or indirectly regulated by a number of transcriptional regulators, and consequently, their expression is sensitive to environmental conditions. In this report, the activities of these two quorum-sensing systems have been examined systematically under 46 growth conditions, and the regulation by environmental conditions has been investigated. The relative timing and strength of expression of these two systems varied significantly under different conditions, which contrasts with the notion of a preset hierarchy with these two systems in P. aeruginosa. Depending on the growth conditions, the correlation between each synthase and its cognate transcriptional regulator also varied, suggesting that the transcription of these genes independently allows for further fine tuning of each system. Finally, we observe that the activities of both the lasI-lasR and the rhlI-rhlR quorum-sensing systems were dramatically enhanced in the presence of extracts of sputum samples from cystic fibrosis patients.

scholarly journals Antimicrobial effect of farnesol, a Candida albicans quorum sensing molecule, on Paracoccidioides brasiliensis growth and morphogenesis

2009 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Lorena S Derengowski ◽  
Calliandra De-Souza-Silva ◽  
Shélida V Braz ◽  
Thiago M Mello-De-Sousa ◽  
Sônia N Báo ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Paracoccidioides Brasiliensis ◽  
Antimicrobial Effect ◽  
Quorum Sensing Molecule

scholarly journals Inhibition of Candida albicans Biofilm Formation by Farnesol, a Quorum-Sensing Molecule

2002 ◽  
Vol 68 (11) ◽  
pp. 5459-5463 ◽  
Author(s):  
Gordon Ramage ◽  
Stephen P. Saville ◽  
Brian L. Wickes ◽  
José L. López-Ribot
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Northern Blot Analysis ◽  
Adherent Cell ◽  
Naturally Occurring ◽  
Biofilm Development ◽  
Further Development ◽  
Quorum Sensing Molecule

ABSTRACT Farnesol is a quorum-sensing molecule that inhibits filamentation in Candida albicans. Both filamentation and quorum sensing are deemed to be important factors in C. albicans biofilm development. Here we examined the effect of farnesol on C. albicans biofilm formation. C. albicans adherent cell populations (after 0, 1, 2, and 4 h of adherence) and preformed biofilms (24 h) were treated with various concentrations of farnesol (0, 3, 30, and 300 μM) and incubated at 37°C for 24 h. The extent and characteristics of biofilm formation were then assessed microscopically and with a semiquantitative colorimetric technique based on the use of 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide. The results indicated that the effect of farnesol was dependent on the concentration of this compound and the initial adherence time, and preincubation with 300 μM farnesol completely inhibited biofilm formation. Supernatant media recovered from mature biofilms inhibited the ability of planktonic C. albicans to form filaments, indicating that a morphogenetic autoregulatory compound is produced in situ in biofilms. Northern blot analysis of RNA extracted from cells in biofilms indicated that the levels of expression of HWP1, encoding a hypha-specific wall protein, were decreased in farnesol-treated biofilms compared to the levels in controls. Our results indicate that farnesol acts as a naturally occurring quorum-sensing molecule which inhibits biofilm formation, and we discuss its potential for further development and use as a novel therapeutic agent.

scholarly journals Candida albicans-Conditioned Medium Protects Yeast Cells from Oxidative Stress: a Possible Link between Quorum Sensing and Oxidative Stress Resistance

2005 ◽  
Vol 4 (10) ◽  
pp. 1654-1661 ◽  
Author(s):  
Caroline Westwater ◽  
Edward Balish ◽  
David A. Schofield
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Candida Albicans ◽  
Stress Response ◽  
Quorum Sensing ◽  
Conditioned Medium ◽  
Oxidative Stress Response ◽  
Yeast Cells ◽  
Protective Response ◽  
Quorum Sensing Molecule

ABSTRACT Candida albicans, the most frequent fungal pathogen of humans, encounters high levels of oxidants following ingestion by professional phagocytes and through contact with hydrogen peroxide-producing bacteria. In this study, we provide evidence that C. albicans is able to coordinately regulate the oxidative stress response at the global cell population level by releasing protective molecules into the surrounding medium. We demonstrate that conditioned medium, which is defined as a filter-sterilized supernatant from a C. albicans stationary-phase culture, is able to protect yeast cells from both hydrogen peroxide and superoxide anion-generating agents. Exponential-phase yeast cells preexposed to conditioned medium were able to survive levels of oxidative stress that would normally kill actively growing yeast cells. Heat treatment, digestion with proteinase K, pH adjustment, or the addition of the oxidant scavenger alpha-tocopherol did not alter the ability of conditioned medium to induce a protective response. Farnesol, a heat-stable quorum-sensing molecule (QSM) that is insensitive to proteolytic enzymes and is unaffected by pH extremes, is partly responsible for this protective response. In contrast, the QSM tyrosol did not alter the sensitivity of C. albicans cells to oxidants. Relative reverse transcription-PCR analysis indicates that Candida-conditioned growth medium induces the expression of CAT1, SOD1, SOD2, and SOD4, suggesting that protection may be mediated through the transcriptional regulation of antioxidant-encoding genes. Together, these data suggest a link between the quorum-sensing molecule farnesol and the oxidative stress response in C. albicans.

scholarly journals Self-engineering capabilities of bacteria

2005 ◽  
Vol 3 (6) ◽  
pp. 197-214 ◽  
Author(s):  
Eshel Ben-Jacob ◽  
Herbert Levine
Keyword(s):  
Quorum Sensing ◽  
Environmental Conditions ◽  
Genetic Information ◽  
Autonomous System ◽  
Growth Conditions ◽  
Self Organization ◽  
Natural Growth ◽  
Intracellular Level ◽  
Cell Plasticity ◽  
Additional Information

Under natural growth conditions, bacteria can utilize intricate communication capabilities (e.g. quorum-sensing, chemotactic signalling and plasmid exchange) to cooperatively form (self-organize) complex colonies with elevated adaptability—the colonial pattern is collectively engineered according to the encountered environmental conditions. Bacteria do not genetically store all the information required for creating all possible patterns. Instead, additional information is cooperatively generated as required for the colonial self-organization to proceed. We describe how complex colonial forms (patterns) emerge through the communication-based singular interplay between individual bacteria and the colony. Each bacterium is, by itself, a biotic autonomous system with its own internal cellular informatics capabilities (storage, processing and assessment of information). These afford the cell plasticity to select its response to biochemical messages it receives, including self-alteration and the broadcasting of messages to initiate alterations in other bacteria. Hence, new features can collectively emerge during self-organization from the intracellular level to the whole colony. The cells thus assume newly co-generated traits and abilities that are not explicitly stored in the genetic information of the individuals.

scholarly journals Farnesol as a Quorum-sensing Molecule in Candida albicans

2008 ◽  
Vol 49 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Tamaki Cho ◽  
Toshihiro Aoyama ◽  
Mika Toyoda ◽  
Hironobu Nakayama ◽  
Hiroji Chibana ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Quorum Sensing Molecule

Diagnosis of a chronic vaginitis: Characterization of Candida albicans and in vitro antagonistic activities of vaginal Lactobacillus

2015 ◽  
Vol 5 (4) ◽  
pp. 143-150
Author(s):  
Bechelaghem Nadia ◽  
Djibaoui Rachid ◽  
Ettalhi Mehdi ◽  
Arabi Abed
Keyword(s):  
Candida Albicans ◽  
Inhibitory Effect ◽  
Vaginal Swab ◽  
Antagonistic Effect ◽  
Growth Media ◽  
Vaginal Lactobacilli ◽  
Effects Of Ph ◽  
Temperature And Growth

  Long-term use of antibiotics, in the treatment of vaginal infection can lead to Candida overgrowth. The motive of the present study was real case of a woman with chronic vaginitis. During ten years, the patient was subjected to a treatment with antibiotics such as gentamycin and lincomycin. Following remarks of a gynecologist, the complicated infection showed like yeast vaginitis symptoms. Consequently we isolated the germ from a vaginal swab sample taken from the patient, and then it was identified phenotypically and belonged to Candida albicans. Our study was followed by examination of the effects of pH, temperature and growth media on the morphogenesis of the isolated C. albicans. The results showed that pH 7.4, temperature at 37 °C and glucose free medium were optimal conditions for filamentation. In order to study the antagonistic effect of vaginal lactobacilli against C. albicans, we used 23 Lactobacilli isolated from several healthy women. The results showed that all isolates had an inhibitory effect against C. albicans with a maximal zone of 25.67 ± 0.58 mm obtained by the isolate L17.

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