Browsing by Author "Vera Lizcano, Omaira"
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Item Acumulación de mercurio y plomo, en el bivalvo Anadara tuberculosa, entre los años 2016 y 2018 en la desembocadura del río Dagua, Pacífico Colombiano(Universidad Santiago de Cali, 2019) Lucero Rincón, Carlos Hernán; Vera Lizcano, OmairaPollution due to mercury and lead has caused great concern in international entities due to the loss of biodiversity in coastal ecosystems and damage to health. In order to evaluate the presence of mercury and lead in the mouth of the Colombian Dagua-Pacific river, as it is an ecosystem of great ecological and economic importance for the region, seven samplings were carried out between July 2016 and January 2018, sediment samples were obtained and physicochemical parameters of the water in the area were measured. Specimens of the bivalve, Anadara tuberculosa, were used to determine the concentration of mercury and lead in tissues and for bioassays with mercury, due to its ability to bioaccumulate metals. A mean mercury concentration of 0.57± 0.74 mg/kg and lead 0.87 mg/kg ± 0.68 in sediment were found, with maximum values of 1.96 mg/kg Hg and 2.05 mg/kg Pb. The presence of mercury in sediments and water is positively related to the concentrations of this metal in organisms. Bioassays with the bivalve A. tuberculosa, allowed to conclude that at low mercury exposure concentrations (0.25 ppm), lesions are generated in animal tissue, mainly in sexual cells. The high concentrations of mercury and lead found in the organisms exceed the maximum permitted concentration established in Colombia for mercury (0.5 mg/kg) and lead (0.20 mg/kg). In addition, the contamination factor for mercury (FC =228000 μg/g) and lead (FC =1242.85 μg/g) are considered very high, as is the potential contamination index for mercury (CP=3.44 μg/g). This allows us to infer that the presence of metals in the tissue of these bivalves present in the mouth of the Dagua river can generate alterations in the ecosystem with possible consequences on human health due to the consumption of these foods.Item Genetic diversity of chloroquine-resistant Plasmodium vivax parasites from the western Brazilian Amazon(Memorias do Instituto Oswaldo Cruz, 2014) Vera Lizcano, Omaira; Resende, Sarah Stela; Chehuan, Yonne F.; Guimarães Lacerda, Marcus Vinicius; A. Brito, Cristiana F.; Zalis, Mariano G.The molecular basis of Plasmodium vivax chloroquine (CQ) resistance is still unknown. Elucidating the molecular background of parasites that are sensitive or resistant to CQ will help to identify and monitor the spread of resistance. By genotyping a panel of molecular markers, we demonstrate a similar genetic variability between in vitro CQ-resistant and sensitive phenotypes of P. vivax parasites. However, our studies identified two loci (MS8 and MSP1-B10) that could be used to discriminate between both CQ-susceptible phenotypes among P. vivax isolates in vitro. These preliminary data suggest that microsatellites may be used to identify and to monitor the spread of P. vivax-resistance around the world.Item The role of the peritrophic matrix and red blood cell concentration in Plasmodium vivax infection of Anopheles aquasalis.(Parasites and Vectors, 2018) Baia-da-Silva, Djane Clarys; Salazar Alvarez, Luis Carlos; Vera Lizcano, Omaira; Maranhão Costa, Fabio Trindade; Costa Pinto Lopes, Stefanie; Silva Orfanó, Alessandra; Oliveira Pascoal, Denner; Nacif-Pimenta, Rafael; Cabral Rodriguez, Iria; Barbosa Guerra, Maria das Graças Vale; Guimarães Lacerda, Marcus Vinicius; Costa Secundino, Nagila Francinete; Monteiro, Wuelton Marcelo; Paolucci Pimenta, Paulo FilemonBackground: Plasmodium vivax is predominant in the Amazon region, and enhanced knowledge of its development inside a natural vector, Anopheles aquasalis, is critical for future strategies aimed at blocking parasite development. The peritrophic matrix (PM), a chitinous layer produced by the mosquito midgut in response to blood ingestion, is a protective barrier against pathogens. Plasmodium can only complete its life-cycle, and consequently be transmitted to a new host, after successfully passing this barrier. Interestingly, fully engorged mosquitoes that had a complete blood meal form a thicker, well-developed PM than ones that feed in small amounts. The amount of red blood cells (RBC) in the blood meal directly influences the production of digestive enzymes and can protect parasites from being killed during the meal digestion. A specific study interrupting the development of the PM associated with the proteolytic activity inhibition, and distinct RBC concentrations, during the P. vivax infection of the New World malaria vector An. aquasalis is expected to clarify whether these factors affect the parasite development. Results: Absence of PM in the vector caused a significant reduction in P. vivax infection. However, the association of chitinase with trypsin inhibitor restored infection rates to those of mosquitoes with a structured PM. Also, only the ingestion of trypsin inhibitor by non-chitinase treated mosquitoes increased the infection intensity. Moreover, the RBC concentration in the infected P. vivax blood meal directly influenced the infection rate and its intensity. A straight correlation was observed between RBC concentrations and infection intensity. Conclusions: This study established that there is a balance between the PM role, RBC concentration and digestive enzyme activity influencing the establishment and development of P. vivax infection inside An. aquasalis. Our results indicate that the absence of PM in the midgut facilitates digestive enzyme dispersion throughout the blood meal, causing direct damage to P. vivax. On the other hand, high RBC concentrations support a better and thick, well-developed PM and protect P. vivax from being killed. Further studies of this complex system may provide insights into other details of the malaria vector response to P. vivax infection.