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Acácio Gonçalves Rodrigues - One of the best experts on this subject based on the ideXlab platform.
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inhibition of Germ Tube formation by candida albicans by local anesthetics an effect related to ionic channel blockade
Current Microbiology, 2000Co-Authors: Acácio Gonçalves Rodrigues, Per-anders Mårdh, Cidalia Pinavaz, Jose Martinezdeoliveira, Antonio FreitasdafonsecaAbstract:Formation of Germ Tubes by Candida albicans has been assumed as a putative virulence factor. Local anesthetics (LAs), e.g., lidocaine and bupivacaine, are known to inhibit Germ Tube formation. The study confirmed this observation for the novel drug ropivacaine, although it was less potent than the former two drugs. Hypothesizing that the effect is due to blockading ionic channels, we exposed Candida albicans to selective calcium blockers, i.e., nifedipine and verapamil, and to a general blocker of ionic channels, i.e., lanthanum. All blockers inhibited Germ Tube formation. The effect was dose-dependent and pH-independent. Addition of calcium reverted the effect of the blockers as well as the effect of lidocaine and ropivacaine. The study suggests that the inhibitory effect of LAs on Germ Tube formation by C. albicans is due to blockade of ionic channels, particularly calcium channels. Therefore, LAs can affect morphology and probably also the pathogenesis of C. albicans.
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In vitro effect of fibrinogen on Candida Albicans Germ Tube formation
APMIS : acta pathologica microbiologica et immunologica Scandinavica, 1999Co-Authors: Acácio Gonçalves Rodrigues, Cidália Irene Azevedo Pina Vaz, Per-anders Mårdh, A F Da Fonseca, J M De OliveiraAbstract:Pseudohyphae formation by Candida albicans blastoconidia, as seen in vaginal smears, is a phenotypical change commonly assumed to mean fungal invasiveness, i.e. not mere colonization. C. albicans forms Germ Tubes in vitro in the presence of serum. In our search for inhibitory components of Germ Tube formation, we decided to study fibrinogen. The inhibition of Germ Tube formation by clinical isolates of C. albicans was evaluated in the presence of serial concentrations of fraction I, type IV and fraction I, type Is of fibrinogen from bovine plasma. Fibrinogen showed a dose-dependent, pH-independent inhibitory effect on the Germ Tube formation by C. albicans.
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Germ Tube formation changes surface hydrophobicity of candida cells
Infectious Diseases in Obstetrics & Gynecology, 1999Co-Authors: Acácio Gonçalves Rodrigues, Per-anders Mårdh, Cidalia Pinavaz, Jose Martinezdeoliveira, Antonio Manuel Leal Ferreira Mendonca Da FonsecaAbstract:Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane), 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of Germ Tube formation on adhesion were studied. C. albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ Tube formation was associated with a significant rise in cell surface hydrophobicity.
Lakshman P. Samaranayake - One of the best experts on this subject based on the ideXlab platform.
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The effect of limited exposure to antifungal agents on the Germ Tube formation of oral Candida albicans
Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pat, 2007Co-Authors: Arjuna N. B. Ellepola, Lakshman P. SamaranayakeAbstract:Candidal adherence has been implicated as the first step in the pathogenesis of oral candidosis, and Germ Tube formation by Candida albicans has been attributed as a co-factor that promotes adherence. Oral candidosis is treated with polyenes and the azole group of antifungal agents. As the intraoral concentrations of antifungals fluctuate considerably due to the dynamics of the oral cavity, we investigated the effect of short exposure to sub-lethal concentrations of antifungals on the Germ Tube formation of Candida albicans. After determining the minimum inhibitory concentration (MIC) of the antifungal agents, ten oral isolates of Candida albicans were exposed to sub-lethal concentrations of nystatin (6xMIC), amphotericin B (8xMIC), 5-fluorocytosine (8xMIC), ketoconazole (4xMIC) and fluconazole (4xMIC), for 1 h. Following removal of the antifungal agent and subsequent incubation in a Germ Tube-inducing medium, the Germ Tube formation of these isolates was quantified. When compared with the controls, exposure to nystatin and amphotericin B almost completely inhibited Germ Tube formation of all the isolates (mean percentage reduction of 97.68 and 97.52%, respectively; P
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the effect of limited exposure to antifungal agents on the Germ Tube formation of oral candida albicans
Journal of Oral Pathology & Medicine, 2007Co-Authors: Arjuna N. B. Ellepola, Lakshman P. SamaranayakeAbstract:Candidal adherence has been implicated as the first step in the pathogenesis of oral candidosis, and Germ Tube formation by Candida albicans has been attributed as a co-factor that promotes adherence. Oral candidosis is treated with polyenes and the azole group of antifungal agents. As the intraoral concentrations of antifungals fluctuate considerably due to the dynamics of the oral cavity, we investigated the effect of short exposure to sub-lethal concentrations of antifungals on the Germ Tube formation of Candida albicans. After determining the minimum inhibitory concentration (MIC) of the antifungal agents, ten oral isolates of Candida albicans were exposed to sub-lethal concentrations of nystatin (6xMIC), amphotericin B (8xMIC), 5-fluorocytosine (8xMIC), ketoconazole (4xMIC) and fluconazole (4xMIC), for 1 h. Following removal of the antifungal agent and subsequent incubation in a Germ Tube-inducing medium, the Germ Tube formation of these isolates was quantified. When compared with the controls, exposure to nystatin and amphotericin B almost completely inhibited Germ Tube formation of all the isolates (mean percentage reduction of 97.68 and 97.52%, respectively; P<0.0001), while ketoconazole suppressed this activity to a lesser degree (30.84%; P=0.0174). However, 5-fluorocytosine- and fluconazole-mediated Germ Tube suppression was minimal (12.63 and 15.93%, respectively; P=0.3255 and P=0.3791). In clinical terms, these findings indicate that short exposure to sub-therapeutic levels of commonly prescribed antifungals may modulate candidal Germ Tube formation, and thereby the clearance of the organisms from the oral cavity.
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The effect of oral bacteria on Candida albicans Germ-Tube formation
APMIS : acta pathologica microbiologica et immunologica Scandinavica, 2001Co-Authors: Raj G. Nair, Sukumaran Anil, Lakshman P. SamaranayakeAbstract:A total of eight bacterial isolates belonging to six species, and a select group of 12 oral Candida albicans isolates, were used to study the effect of bacteria on Germ-Tube formation. Briefly, each bacterial suspension (10(5-6) cells/ml) was mixed with a C. albicans suspension (10(7) cells/ml) and incubated at 37 degrees C for 90 min with bovine serum, and the percentage Germ-Tube-positive Candida cells was quantified using a haemocytometer, under light microscopy. In general, out of eight bacteria, Streptococcus sanguis SK21A, Streptococcus salivarius SK56, Escherichia coli ATCC 25922, and S. salivarius OBU3 suppressed Germ-Tube formation to varying degrees, with different C albicans isolates. Porphyromonas gingivalis Pg 50, Lactobacillus casei ATCC 7469 and Prevotella intermedia OBU4 elicited significant enhancement of Germ-Tube formation, whereas S. sanguis OBU 2 had no effect. E. coli ATCC 25922 was the only organism to show statistically significant suppression of Germ-Tube formation (p=0.0312). A significant increase in the Germ Tube production of C. albicans isolated from HIV-infected compared with HIV-free individuals was also noted. The current results tend to suggest that commensal and transient oral bacterial populations may selectively influence the differential expression of Germ-Tube-forming ability of C. albicans isolates.
W. Lajean Chaffin - One of the best experts on this subject based on the ideXlab platform.
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Coordination of Germ Tube formation and surface antigen expression in Candida albicans.
FEMS microbiology letters, 1994Co-Authors: Vishnu P. Chaturvedi, Ricardo A. Vanegas, W. Lajean ChaffinAbstract:If the determinants of shape and cell wall topography are independently regulated and induced in Germ Tube formation in Candida albicans, these processes may be separable in a non-Germ Tube forming strain. The expression of several preferentially expressed hyphal surface components in a parental, non-Germ Tube forming variant, and a Germ Tube forming revertant strain were examined by indirect immunofluorescence. The proportion of Germ Tubes expressing the determinants and the morphological localization of expression was similar. Few yeast cells in Germ Tube cultures bound probes and there was no increase in binding by yeast cells of the variant strain. Extraction with β-mercaptoethanol prior to analysis had little effect on probe binding and the shape of yeast cells were similar. These observations suggest the ability to promote apical expansion in Germ Tube formation and surface expression of certain markers were coordinately regulated.
Murray T Brown - One of the best experts on this subject based on the ideXlab platform.
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sensitivity of spore Germination and Germ Tube elongation of saccharina japonica to metal exposure
Ecotoxicology, 2011Co-Authors: Taejun Han, Jeongae Kong, Heegyu Kang, Seonjin Kim, Gyosun Jin, Hoon Choi, Murray T BrownAbstract:The sensitivity of early life stages of the brown seaweed Saccharina japonica to six metals (Cd, Cu, Hg, Ni, Pb, Zn) and two waste-water samples were investigated and a new toxicity bioassay developed. The two endpoints used were spore Germination and Germ Tube elongation with an exposure time of 24 h. Optimal test conditions determined for photon irradiance, pH, salinity and temperature were darkness, pH 8, 35‰ and 15°C, respectively. The toxicity ranking of five metals was: Hg (EC(50) of 41 and 42 μg l(-1)) > Cu (120 and 81 μg l(-1)) > Ni (2,009 and 1,360 μg l(-1)) > Zn (3,024 and 3,897 μg l(-1)) > Pb (4,760 and 4,429 μg l(-1)) > Cd (15,052 and 7,541 μg l(-1)) for Germination and Germ Tube elongation, respectively. The sensitivities to Cd, Cu and Ni were greater in Germ Tube elongation than in Germination process. When tested against two different waste-water samples (processed animal and printed circuit board waste-water) values of EC(50) were between 21.29 and 32.02% for Germination and between 5.33 and 8.98% for Germ Tube elongation. Despite differences in their chemical composition, the toxic effects of waste-water samples, as indicated by EC(50) values, did not differ significantly for the same endpoints. The CV range for both Germination and Germ Tube elongation was between 4.61 and 37.69%, indicating high levels of precision of the tests. The results compare favourably with those from more established test procedures employing micro- and macroalgae. The advantages and potential limitations of the bioassay for the assessment of anthropogenic impacts on coastal ecosystems and commercial cultivation areas in near-shore environments are discussed.
Per-anders Mårdh - One of the best experts on this subject based on the ideXlab platform.
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inhibition of Germ Tube formation by candida albicans by local anesthetics an effect related to ionic channel blockade
Current Microbiology, 2000Co-Authors: Acácio Gonçalves Rodrigues, Per-anders Mårdh, Cidalia Pinavaz, Jose Martinezdeoliveira, Antonio FreitasdafonsecaAbstract:Formation of Germ Tubes by Candida albicans has been assumed as a putative virulence factor. Local anesthetics (LAs), e.g., lidocaine and bupivacaine, are known to inhibit Germ Tube formation. The study confirmed this observation for the novel drug ropivacaine, although it was less potent than the former two drugs. Hypothesizing that the effect is due to blockading ionic channels, we exposed Candida albicans to selective calcium blockers, i.e., nifedipine and verapamil, and to a general blocker of ionic channels, i.e., lanthanum. All blockers inhibited Germ Tube formation. The effect was dose-dependent and pH-independent. Addition of calcium reverted the effect of the blockers as well as the effect of lidocaine and ropivacaine. The study suggests that the inhibitory effect of LAs on Germ Tube formation by C. albicans is due to blockade of ionic channels, particularly calcium channels. Therefore, LAs can affect morphology and probably also the pathogenesis of C. albicans.
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In vitro effect of fibrinogen on Candida Albicans Germ Tube formation
APMIS : acta pathologica microbiologica et immunologica Scandinavica, 1999Co-Authors: Acácio Gonçalves Rodrigues, Cidália Irene Azevedo Pina Vaz, Per-anders Mårdh, A F Da Fonseca, J M De OliveiraAbstract:Pseudohyphae formation by Candida albicans blastoconidia, as seen in vaginal smears, is a phenotypical change commonly assumed to mean fungal invasiveness, i.e. not mere colonization. C. albicans forms Germ Tubes in vitro in the presence of serum. In our search for inhibitory components of Germ Tube formation, we decided to study fibrinogen. The inhibition of Germ Tube formation by clinical isolates of C. albicans was evaluated in the presence of serial concentrations of fraction I, type IV and fraction I, type Is of fibrinogen from bovine plasma. Fibrinogen showed a dose-dependent, pH-independent inhibitory effect on the Germ Tube formation by C. albicans.
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Germ Tube formation changes surface hydrophobicity of candida cells
Infectious Diseases in Obstetrics & Gynecology, 1999Co-Authors: Acácio Gonçalves Rodrigues, Per-anders Mårdh, Cidalia Pinavaz, Jose Martinezdeoliveira, Antonio Manuel Leal Ferreira Mendonca Da FonsecaAbstract:Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane), 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of Germ Tube formation on adhesion were studied. C. albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ Tube formation was associated with a significant rise in cell surface hydrophobicity.