scholarly journals Photodynamic Effect of 5,10,15,20-Tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin towards the Human Pathogen Candida albicans under Different Culture Conditions

Photochem ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 505-522
Author(s):  
Paula V. Cordero ◽  
Darío D. Ferreyra ◽  
María E. Pérez ◽  
María G. Alvarez ◽  
Edgardo N. Durantini
Keyword(s):  
Candida Albicans ◽  
Culture Conditions ◽  
Oxygen Species ◽  
Type Ii ◽  
Planktonic Cells ◽  
Quenching Rate ◽  
Log Reduction ◽  
Quenching Rate Constant ◽  
Bimolecular Quenching ◽  
Human Pathogen Candida Albicans

Photocytotoxic activity sensitized by 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin (TAPC) was investigated in Candida albicans under different culture conditions. Planktonic cells incubated with 2.5 μM TAPC were eradicated after 5 min irradiation with white light. Studies in the presence of reactive oxygen species scavengers indicated the involvement of mainly a type II mechanism. Furthermore, cell growth of C. albicans was suppressed in the presence of 5 μM TAPC. A decrease in pseudohyphae survival of 5 log was found after 30 min irradiation. However, the photokilling of this virulence factor reached a 1.5 log reduction in human serum. The uptake of TAPC by pseudohyphae decreased in serum due to the interaction of TAPC with albumin. The binding constant of the TAPC-albumin complex was ~104 M−1, while the bimolecular quenching rate constant was ~1012 s−1 M−1, indicating that this process occurred through a static process. Thus, the photoinactivation of C. albicans was considerably decreased in the presence of albumin. A reduction of 2 log in cell survival was observed using 4.5% albumin and 30 min irradiation. The results allow optimizing the best conditions to inactivate C. albicans under different culture conditions.

scholarly journals Elucidating the Photoluminescence Quenching in Ensulizole: An Artificial Water Soluble Sunscreen

2021 ◽  
Author(s):  
Muhammad Mubeen ◽  
Muhammad Adnan Khalid ◽  
Maria Mukhtar ◽  
Saba Shahrum ◽  
Shanila Zahra ◽  
...  
Keyword(s):  
Dominant Mode ◽  
Water Soluble ◽  
Premature Aging ◽  
Absorption Feature ◽  
Dynamic Mode ◽  
Quenching Rate ◽  
Polar Solvents ◽  
Quenching Rate Constant ◽  
Bimolecular Quenching ◽  
Steady State Absorption

Abstract Employing natural or artificial sunscreens is essential to protect the skin from ultraviolet radiations that cause premature aging and develop melanoma and other forms of skin cancer. The 2-Phenylbenzimidazole-5-sulfonic acid, commonly known as ensulizole is a water-soluble artificial sunscreen that absorbs mostly UV-B (280 nm − 315 nm) radiations and protects the skin against the harmful effects of these radiations. Steady-state absorption indicates a strong absorption feature at 303 nm and a weak at 316 nm that have been identified as π → π* and n → π* transitions, respectively. The photoluminescence (PL) spectra indicate that the PL of ensulizole is less Stokes-shifted in polar solvents and more Stokes-shifted in non-polar solvents. The average PL lifetime of ensulizole is longer in non-polar solvents as compared to polar solvents and it exhibits the shortest PL lifetime in aqueous medium that signifies its efficiency in water. This suggests in non-polar solvents intersystem crossing is the dominant mode of relaxation of the excited ππ* state. Furthermore, an increase of pH of ensulizole solution decreases the PL intensity and the lifetime. Stern-Volmer equation is employed to evaluate bimolecular quenching rate constant kq that suggests the diffusional dynamic mode of PL quenching is operative.

Interaction of Nitroglycerin with Bovine Serum Albumin and the Influence of Metal Ions on the Binding

2020 ◽  
Vol 42 (2) ◽  
pp. 180-180
Author(s):  
Chengman Bao Chengman Bao ◽  
Jialian Wang Jialian Wang ◽  
Xuehong Tong Xuehong Tong ◽  
Chunli Zhang Chunli Zhang ◽  
Xinhui Tang Xinhui Tang
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Metal Ions ◽  
Bovine Serum ◽  
Binding Constants ◽  
Entropy Change ◽  
Quenching Rate ◽  
Different Temperatures ◽  
Quenching Rate Constant ◽  
Bimolecular Quenching

The effect of Cu2+, Ca2+, Mg2+and Zn2+ on the interaction between nitroglycerin and bovine serum albumin was investigated. The bimolecular quenching rate constant, the Stern-Volmer quenching constant, the binding constants and the number of binding sites were calculated in the absence and presence of Cu2+, Ca2+, Mg2+and Zn2+. The quenching constants of nitroglycerin to bovine serum albumin were increased in the presence of metal ions. Static quenching mechanism was also confirmed. The binding constants of nitroglycerin to bovine serum albumin were influenced by different metal ions. The enthalpy change, free energy chang, entropy change and the distance between the donor and the acceptor at different temperatures were calculated. The results indicated that energy transfer from bovine serum albumin to nitroglycerin occurs with high probability.

A Spectroscopic Approach with Theoretical Studies to Study the Interaction of 9-aminoacridine with Certain Phenols

2017 ◽  
Vol 231 (5) ◽  
Author(s):  
Chandrakumar Manivannan ◽  
Rajadurai Vijay Solomon ◽  
Ponnambalam Venuvanalingam ◽  
Rajalingam Renganathan
Keyword(s):  
Steady State ◽  
Bathochromic Shift ◽  
Acetonitrile Solution ◽  
Theoretical Studies ◽  
Time Resolved Fluorescence ◽  
Quenching Rate ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Quenching Rate Constant ◽  
Bimolecular Quenching

AbstractThe influence of phenols upon the fluorescence quenching of 9-aminoacridine (9-AA) was examined in acetonitrile solution by employing steady state and time-resolved fluorescence measurements. On increasing the concentration of quencher molecules the absorption spectra of 9-AA change with significant bathochromic shift. The fluorescence intensity of 9-AA change in presence of quencher molecules were measured at various temperatures as a function of the quencher concentrations. The observed bimolecular quenching rate constant (k

scholarly journals Antifungal Effects of Saponin Extract from Rhizomes of Dioscorea panthaica Prain et Burk against Candida albicans

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Longfei Yang ◽  
Xin Liu ◽  
Xinming Zhuang ◽  
Xuechao Feng ◽  
Lili Zhong ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Antifungal Drugs ◽  
Ros Production ◽  
Oxygen Species ◽  
Planktonic Cells ◽  
Endogenous Reactive Oxygen Species ◽  
Antifungal Effects

Candida albicans is the most common fungal pathogen causing serious diseases, while there are only a paucity of antifungal drugs. Therefore, the present study was performed to investigate the antifungal effects of saponin extract from rhizomes of Dioscorea panthaica Prain et Burk (Huangshanyao Saponin extract, HSE) against C. albicans. HSE inhibits the planktonic growth and biofilm formation and development of C. albicans. 16–64 μg/mL of HSE could inhibit adhesion to polystyrene surfaces, transition from yeast to filamentous growth, and production of secreted phospholipase and could also induce endogenous reactive oxygen species (ROS) production and disrupt cell membrane in planktonic cells. Inhibitory activities against extracellular exopolysaccharide (EPS) production and ROS production in preformed biofilms could be inhibited by 64–256 μg/mL of HSE. Cytotoxicity against human Chang’s liver cells is low, with a half maximal inhibitory concentration (IC50) of about 256 μg/mL. In sum, our study suggested that HSE might be used as a potential antifungal therapeutic against C. albicans.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

scholarly journals Early Adhesion of Candida albicans onto Dental Acrylic Surfaces

2017 ◽  
Vol 96 (8) ◽  
pp. 917-923 ◽  
Author(s):  
S. Aguayo ◽  
H. Marshall ◽  
J. Pratten ◽  
D. Bradshaw ◽  
J.S. Brown ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Clinical Isolate ◽  
Force Spectroscopy ◽  
Laboratory Strain ◽  
Culture Conditions ◽  
The Body ◽  
Yeast Cells ◽  
Adhesion Forces ◽  
Reliable Technique ◽  
Mother Cells

Denture-associated stomatitis is a common candidal infection that may give rise to painful oral symptoms, as well as be a reservoir for infection at other sites of the body. As poly (methyl methacrylate) (PMMA) remains the main material employed in the fabrication of dentures, the aim of this research was to evaluate the adhesion of Candida albicans cells onto PMMA surfaces by employing an atomic force microscopy (AFM) single-cell force spectroscopy (SCFS) technique. For experiments, tipless AFM cantilevers were functionalized with PMMA microspheres and probed against C. albicans cells immobilized onto biopolymer-coated substrates. Both a laboratory strain and a clinical isolate of C. albicans were used for SCFS experiments. Scanning electron microscopy (SEM) and AFM imaging of C. albicans confirmed the polymorphic behavior of both strains, which was dependent on growth culture conditions. AFM force-spectroscopy results showed that the adhesion of C. albicans to PMMA is morphology dependent, as hyphal tubes had increased adhesion compared with yeast cells ( P < 0.05). C. albicans budding mother cells were found to be nonadherent, which contrasts with the increased adhesion observed in the tube region. Comparison between strains demonstrated increased adhesion forces for a clinical isolate compared with the lab strain. The clinical isolate also had increased survival in blood and reduced sensitivity to complement opsonization, providing additional evidence of strain-dependent differences in Candida-host interactions that may affect virulence. In conclusion, PMMA-modified AFM probes have shown to be a reliable technique to characterize the adhesion of C. albicans to acrylic surfaces.

scholarly journals A conserved fungal hub protein involved in adhesion and drug resistance in the human pathogen Candida albicans

2018 ◽  
Vol 4 ◽  
pp. 10-19 ◽  
Author(s):  
Hélène Martin-Yken ◽  
Tina Bedekovic ◽  
Alexandra C. Brand ◽  
Mathias L. Richard ◽  
Sadri Znaidi ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Human Pathogen ◽  
Human Pathogen Candida Albicans

scholarly journals Expression of highly selective sodium channels in alveolar type II cells is determined by culture conditions

2001 ◽  
Vol 280 (4) ◽  
pp. L646-L658 ◽  
Author(s):  
Lucky Jain ◽  
Xi-Juan Chen ◽  
Semra Ramosevac ◽  
Lou Ann Brown ◽  
Douglas C. Eaton
Keyword(s):  
Single Channel ◽  
Apical Membrane ◽  
Culture Conditions ◽  
Alveolar Type ◽  
Type Ii ◽  
Biophysical Properties ◽  
Air Interface ◽  
The Individual ◽  
Permeable Supports

Alveolar fluid clearance in the developing and mature lungs is believed to be mediated by some form of epithelial Na channels (ENaC). However, single-channel studies using isolated alveolar type II (ATII) cells have failed to demonstrate consistently the presence of highly selective Na+ channels that would be expected from ENaC expression. We postulated that in vitro culture conditions might be responsible for alterations in the biophysical properties of Na+conductances observed in cultured ATII cells. When ATII cells were grown on glass plates submerged in media that lacked steroids, the predominant channel was a 21-pS nonselective cation channel (NSC) with a Na+-to-K+ selectivity of 1; however, when grown on permeable supports in the presence of steroids and air interface, the predominant channel was a low-conductance (6.6 ± 3.4 pS, n = 94), highly Na+-selective channel (HSC) with a P Na/ P K >80 that is inhibited by submicromolar concentrations of amiloride ( K 0.5 = 37 nM) and is similar in biophysical properties to ENaC channels described in other epithelia. To establish the relationship of this HSC channel to the cloned ENaC, we employed antisense oligonucleotide methods to inhibit the individual subunit proteins of ENaC (α, β, and γ) and used patch-clamp techniques to determine the density of this channel in apical membrane patches of ATII cells. Overnight treatment of cells with antisense oligonucleotides to any of the three subunits of ENaC resulted in a significant decrease in the density of HSC channels in the apical membrane cell-attached patches. Taken together, these results show that when grown on permeable supports in the presence of steroids and air interface, the predominant channels expressed in ATII cells have single-channel characteristics resembling channels that are associated with the coexpression of the three cloned ENaC subunits α-, β-, and γ-ENaC.

Lifetime of Singlet Oxygen and Quenching by NaN3 in Mixed Solvents

1982 ◽  
Vol 37 (5) ◽  
pp. 649-652 ◽  
Author(s):  
N. Miyoshi ◽  
M. Ueda ◽  
K. Fuke ◽  
Y. Tanimoto ◽  
M. Itoh ◽  
...  
Keyword(s):  
Activation Energy ◽  
Charge Transfer ◽  
Singlet Oxygen ◽  
Mixed Solvents ◽  
Solvent Polarity ◽  
Thermal Lensing ◽  
Partial Charge ◽  
Partial Charge Transfer ◽  
Quenching Rate ◽  
Quenching Rate Constant

Singlet oxygen was generated by the photosensitization of erythrosine. The lifetime of singlet oxygen and the quenching rate constant for singlet oxygen by NaN3 were measured by a thermal lensing method in MeOH-H2O mixed solvents. The reciprocal of the lifetime increased linearly with the increase of the H2O mole fraction. Semi-log plot of the quenching constant against the reciprocal of the solvent polarity exhibited a linear relation. The quenching of the singlet oxygen by NaN3 may proceed through a partial charge-transfer intermediate. The activation energy for the quenching reaction of N3- + 1O2 →[N3·1O2-] increased with the increase of the solvent polarity. The lifetime was also measured in MeOH-ethyleneglycol mixed solvents, and its relation with viscosity was obtained

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