Browsing by Author "Rivera Sanchez, Sandra Patricia"
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Item Integrating In Vitro and In Silico Analysis of a Cationic Antimicrobial Peptide Interaction with Model Membranes of Colistin-Resistant Pseudomonas aeruginosa Strains(MDPI, 2022-06) Rivera Sanchez, Sandra Patricia; Ocampo Ibáñez, Iván Darío; Liscano, Yamil; Martínez, Natalia; Muñoz, Isamar; Manrique Moreno, Marcela; Martinez Martinez, Luis; Oñate Garzon, JoséBacterial antibiotic resistance is a serious global public health concern. Infections caused by colistin-resistant Pseudomonas aeruginosa (CRPa) strains represent a serious threat due to their considerable morbidity and mortality rates, since most of the current empirical antibiotic therapies are ineffective against these strains. Accordingly, cationic antimicrobial peptides (CAMPs) have emerged as promising alternatives to control resistant bacteria. In this study, the interaction of a CAMP derived from cecropin D-like (∆M2) with model membranes mimicking bacterial biomembranes of wild-type (WTPa) strains of P. aeruginosa and CRPa was evaluated through in vitro and in silico approaches. In vitro interaction was determined by infrared spectroscopy, whereas in silico molecular dynamics was performed to predict specific interactions between amino acids of ∆M2 and lipids of model membrane systems. Experimental analysis showed this peptide interacted with the lipids of bacteriallike model membranes of WTPa and CRPa. In both cases, an increase in the concentration of peptides induced an increase in the phase transition temperature of the lipid systems. On the other hand, the peptides in solution underwent a transition from a random to a helical secondary structure after interacting with the membranes mostly favored in the CRPa system. The α-helix structure percentage for ∆M2 interacting with WTPa and CRPa lipid systems was 6.4 and 33.2%, respectively. Finally, molecular dynamics showed ∆M2 to have the most affinities toward the phospholipids palmitoyl-oleyl-phosphatidylglycerol (POPG) and palmitoyl-oleoyl-phosphatidylethanolamine (POPE) that mimic membranes of WTPa and CRPa, respectively. This work provides clues for elucidating the membrane-associated mechanism of action of ∆M2 against colistin-susceptible and-resistant strains of Pseudomonas aeruginosa.Item Removal of E. coli and Salmonella in pot ceramic filters operating at different filtration rates(Elsevier Ltd, 2019-05-14) Pérez Vidal, Andrea; Rivera Sanchez, Sandra Patricia; Florez Elvira, Liliana Janeth; Silva Leal, Jorge Antonio; Diaz Gomez, Jaime; Herrera Cuero, Luisa Fernanda; Lopez Botero, Lina PaolaThe use of pot ceramic filters PCF to improve the domestic water quality supply has been recognized as an alternative in regions where there is unsecure water treatment or contamination of the treated water during transport and storage and an absence of safe drinking water. The aim of this study was to evaluate a model of PCF impregnated with colloidal silver under three filtration rates (1.0, 2.0 and 3.0 L/h) and three E. coli and Salmonella spp concentrations (104, 103 and 102 CFU/mL). The evaluation was made using spiked water having a turbidity of 29.9 ± 4.4 NTU and conductivity of 176 ± 31.7 μS/cm. The results showed a turbidity removal efficiency of 97% and average effluent of 0.9 NTU. The microbiological efficiency removal was of 2 Log Reduction Value (LRV) for E. coli and 1 LRV for Salmonella spp. There were not found significant statistical differences between the filtration rates and the removal efficiencies for turbidity E. coli and Salmonella spp. It was observed that the microbiological removal efficiency was affected by biofilm formation a phenomenon that was attributed to the presence of Salmonella spp. The combination of chemical and mechanical cleaning methods contributed to the elimination of the biofilm.