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Background and Purpose: Plasmodium falciparum and P. vivax are responsible for most malaria cases in humans in the African Region and the Americas; these parasites have developed resistance to classic antimalarial drugs. On the other hand, previous investigations of the alkyl-linked bis tetrahydro-(2H)-1,3,5-thiadiazine-2-thione (bis-THTT) derivatives compounds show satisfactory results against protozoan parasites such as Trypanosoma cruzi, Trypanosoma vaginalis, Trypanosoma brucei rhodesiense and Leishmania donovani. Therefore, it is possible to see some effect of bis-THTT derivatives on other protozoan parasites, such as Plasmodium. Experimental Approach: This study aimed to perform an in vivo biological evaluation of bis-THTT (JH1 to JH6) derivatives compounds as possible anti-malaria drugs in BALB/c mice infected with Plasmodium berghei ANKA and Plasmodium yoelii 17XL strains. In this work, we evaluated the compounds as potential antimalarial drugs in BALB/c mice infected with Plasmodium strains. Key Results: For each compound, we assess the percentages of parasitemia by smears from tail blood and the humoral response by indirect ELISA test using each compound as an antigen. We also evaluated the B lymphocyte response and the cytotoxicity of the bis-THTT derivatives compounds with MTT cell proliferation assays. Conclusions: Our results show that the bis-THTT derivatives JH2 and JH4 presented effective parasitemia control in mice infected with P. berghei; JH5 and JH6 compounds have similar infection control results as chloroquine in mice infected P. yoelii strain. The evaluation of bis-THTT derivatives compounds in a model of BALB/c mice infected with P. berghei and P. yoelii allowed us to conclude that some of them have an antimalarial effect; however, none of the tested compounds exceeded the efficiency of chloroquine.
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Wastewater surveillance represents an alternative approach to regulating contamination and the early detection of infectious agents and outbreaks of diseases of public health importance. This study evaluated domestic wastewater effects on recreational waters in estuarine and seawater bodies in Guayas and Santa Elena provinces in Ecuador, South America. Fecal indicator bacteria (thermotolerant coliforms) served as key indicators for evaluation. Physical, chemical, and microbiological quality markers following the Ecuadorian environmental quality standard and the discharge of effluents to the water resource were analyzed. Samples were collected from 44 coastal sites and 2 oxidation lagoons during the dry and rainy seasons of 2020 and 2021, respectively. SARS-CoV-2 RNA was detected in samples with higher E. coli concentrations using reverse transcription quantitative PCR to detect the genes N and ORF1ab. All samples analyzed for SARS-CoV-2 showed Ct Ë 40 for at least one gene. Four samples showed at least 20 genome copies of gene N per reaction. These were at an artisanal fishing port, an estuarine area (Palmar), a recreational bay, and an oxidation lagoon. A moderate correlation was found between SARS-CoV-2 RNA, thermotolerant coliform and E. coli (p-value ≤ 0.0037), and a strong and positive correlation between thermotolerant coliform and E. coli. (p-value ≤ 0.00001), highlighting the utility of these established parameters as a proxy of the virus. Significant differences were found in the concentrations of thermotolerant coliforms between seasons (p-value = 0.016) and sites (p-value = 0.005). The highest levels of coliforms were found in the dry season (63000 MPN/100 mL) in Anconcito and during the rainy season (14000 MPN/100 mL) at Esterillo in Playas County. It is recommended that the decentralized autonomous governments of the surveyed provinces in Ecuador implement urgent corrective actions and establish medium-term mechanisms to minimize a potential contamination route. Additional parameters must be included in the monitoring, such as Enterococcus and intestinal parasites, due to their public health implications. In the oxidation lagoons, maintenance actions must be carried out, including the dissolution of sediments, an increase in water retention times, and in situ treatment of the sludge, to improve the system's performance.
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COVID-19 , RNA Viral , SARS-CoV-2 , Esgotos , Qualidade da Água , Equador , Esgotos/virologia , Esgotos/microbiologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/genética , RNA Viral/genética , RNA Viral/isolamento & purificação , RNA Viral/análise , COVID-19/epidemiologia , COVID-19/virologia , Humanos , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/genética , Microbiologia da Água , Monitoramento Ambiental/métodos , Água do Mar/virologia , Água do Mar/microbiologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Águas Residuárias/virologia , Águas Residuárias/microbiologiaRESUMO
Anthropogenic Marine Litter (AML) accumulating on beaches causes damage to coastal ecosystems and high costs to local communities. Volunteers sampled AML on 130 beaches along the central and southern East Pacific coasts, with AML densities ranging from 0.46 to 2.26 items m-2 in the different countries. AML composition was dominated by plastics and cigarette butts, the latter especially in Mexico and Chile. The accumulation of AML in the upper zones of the beaches and substantial proportions of cigarette butts, glass and metal pointed mainly to local sources. Statistical modelling of litter sources on continental beaches revealed that tourism, access and related infrastructure (e.g. parking lots) best explained AML densities, while plastic densities were also influenced by the distance from river mouths and national Gross Domestic Product. Large-scale monitoring can be a useful tool to evaluate the effectiveness of public policies that should primarily focus on land sources.
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Leucemia Mieloide Aguda , Resíduos , Humanos , Resíduos/análise , Monitoramento Ambiental , Ecossistema , Praias , PlásticosRESUMO
Malaria is a parasitic infection caused by a protozoon of the genus Plasmodium, transmitted to humans by female biting mosquitoes of the genus Anopheles. Chloroquine and its derivates have caused the parasite to develop drug resistance in endemic areas. For this reason, new anti-malarial drugs as treatments are crucial. This work aimed to evaluate the humoral response. with hyper-immune sera, of mice immunized with six derivatives of tetrahydro-(2H)-1,3,5-thiadiazine-2-thione (bis-THTT) by indirect ELISA test. The cross-reactivity between the compounds as antigens and their microbial activity on Gram-positive and Gram-negative bacteria was evaluated. The results of the humoral evaluation by indirect ELISA show that three bis-THTTs react with almost all of the above. Besides, three compounds used as antigens stimulate the BALB/c mice's immune system. The best combination of two antigens as a combined therapy displays similar absorbances between the antigens in the mixture, showing similar recognition by antibodies and their compounds. In addition, our results showed that different bis-THTT presented antimicrobial activity on Gram-positive bacteria, mainly on Staphylococcus aureus strains, and no inhibitory activity was observed on the Gram-negative bacteria tested.
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This study represents an inter-institutional effort that was supported by more than 400 volunteers. We sampled Anthropogenic Marine Debris (AMD) on 26 beaches, including one beach from Galapagos Islands. AMD was mainly composed of plastics (>60%), followed by cigarette butts, paper and metal. Average AMD density on the continental beaches was 1.31 ± 1.03 items m-2 (mean ± SD). AMD densities and the proportion of plastics were higher on some beaches located on the Gulf of Guayaquil, suggesting that many of the plastic items found on these beaches were, likely, drifted by the swift currents of the Guayas River. Additionally, the overall results indicate that most litter on continental beaches from Ecuador has local sources. Recommendations include marine pollution education and public awareness campaigns to reduce the consumption of plastic bags, as well as a ban on harmful single-use plastics.
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Praias , Monitoramento Ambiental , Resíduos , Equador , Humanos , Plásticos , VoluntáriosRESUMO
Large amount of drilling waste associated with the expansion of the Orinoco Oil Belt (OOB), the biggest proven reserve of extra-heavy crude oil (EHCO) worldwide, is usually impregnated with EHCO and highly salinized water-based drilling fluids. Oxidative exoenzymes (OE) of the lignin-degrading enzyme system (LDS) of fungi catalyse the oxidation of a wide range of toxic pollutants. However, very little evidences on fungal degradation or biotransformation of EHCO have been reported, which contain high amounts of asphaltenes and its biodegradation rate is very limited. The aims of this work were to study the ability of Pestalotiopsis palmarum BM-04 to synthesize OE, its potential to biotransform EHCO and to survive in extreme environmental conditions. Enzymatic studies of the LDS showed the ability of this fungus to overproduce high amounts of laccase (LACp) in presence of wheat bran or lignin peroxidase (LIPp) with EHCO as sole carbon and energy source (1300 U mgP(-1) in both cases). FT-IR spectroscopy with Attenuated Total Reflectance (ATR) analysis showed the enzymatic oxidation of carbon and sulfur atoms in both maltenes and asphaltenes fractions of biotreated EHCO catalysed by cell-free laccase-enriched OE using wheat bran as inducer. UV-visible spectrophotometry analysis revealed the oxidation of the petroporphyrins in the asphaltenes fraction of biotreated EHCO. Tolerance assays showed the ability of this fungus to grow up to 50,000 p.p.m. of EHCO and 2000 mM of NaCl. These results suggest that P. palmarum BM-04 is a hopeful alternative to be used in remediation processes in extreme environmental conditions of salinity and EHCO contamination, such as the drilling waste from the OOB.
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Proteínas Fúngicas/metabolismo , Lacase/metabolismo , Petróleo/metabolismo , Xylariales/enzimologia , Biodegradação Ambiental , Biotransformação , Proteínas Fúngicas/genética , Resíduos Industriais/análise , Lacase/genética , Oxirredução , Petróleo/análise , Petróleo/microbiologia , Xylariales/genética , Xylariales/crescimento & desenvolvimento , Xylariales/metabolismoRESUMO
BACKGROUND: The merozoite surface protein (MSP)-1 is a target antigen of protective immunity and a malaria vaccine candidate. The nature of this protective immune response warrants further investigation: although specific antibody is thought to play a major role, the mechanisms of protection are still unclear. Monoclonal antibodies (mAbs) specific for the C-terminus of MSP-1 from Plasmodium yoelii have been shown previously to provide protection against challenge infection when administered by passive immunization to mice. Three protective mAbs were re-examined and, in particular, the effect of combinations of antibodies on the protection provided was studied. It was found that a combination of two antibodies can either provide additive protective effects or result in a suppression of protection. In this report the importance of antibody subclass and epitope specificity in the outcome of these passive immunization experiments are discussed. METHODS: The minimum protective dose (MPD) for each mAb was determined, and then combinations of antibody at their MPD were investigated for their ability to control parasitaemia and promote survival in groups of mice. Mice were inoculated over three days with the MPD and challenged with a blood stage infection of the virulent P. yoelii 17 XL. The resultant parasitaemia was assessed daily on Giemsa-stained blood films. Following the infection the presence of MSP-1 specific antibodies in the sera was monitored, and the proliferative responses of cells in the spleen of protected mice were measured. RESULTS: Combining antibodies resulted in either an additive effect on protection, with reduced peak parasitaemia and better survival, or resulted in a suppression of protection over that achieved by a single antibody alone. An additive effect was observed when B6 and F5 that have the same isotype and similar fine specificity, were combined. However, a combination of mAb D3, an IgG2a, with either B6 or F5 (both IgG3) suppressed protection, an effect that may have been due to the combination of different isotypes or to the different fine specificity of the antibodies. CONCLUSIONS: These results suggest that a combination of protective antibodies with either the same or different isotypes can produce either an additive or a suppressive effect in passive immunization. This phenomenon may be important in better understanding immunity in this experimental mouse model of malaria.
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Anticorpos Monoclonais/imunologia , Epitopos/imunologia , Malária/prevenção & controle , Proteína 1 de Superfície de Merozoito/imunologia , Plasmodium yoelii/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Western Blotting , Proteína 1 de Superfície de Merozoito/sangue , Camundongos , Camundongos Endogâmicos BALB C , Parasitemia/imunologiaRESUMO
Debido a la función vital que desempeñan las plantas en los ecosistemas, estos organismos han sido utilizados para la diagnosis o predicción de las consecuencias negativas de actividades antropogénicas mediante el estudio de sus procesos fisiológicos, respuestas bioquímicas, mecanismos de adaptación y mortalidad. Las respuestas que tienen lugar en los organismos como consecuencia del efecto de un contaminante se han denominado biomarcadores. Éstos pueden definirse como las variaciones bioquímicas, celulares, fisiológicas o comportamentales que pueden ser medidas en el tejido, en los fluidos corporales y/o a nivel del organismo completo, y brindan evidencia de la exposición a uno o más componentes químicos. Los biomarcadores ofrecen información completa y biológicamente relevante sobre el potencial impacto de los contaminantes tóxicos en la salud de los organismos. Tienen la ventaja de poner en evidencia síntomas tempranos del daño causado por el contaminante y, por tanto, pueden ser utilizados como señales de alarma ante la presencia de contaminantes químicos. En este trabajo se analiza información referente a las plantas como posibles bioindicadoras de contaminación por cadmio y de los biomarcadores que pueden ser utilizados para monitoreo ambiental. Para este fin, se describe al Cd como contaminante ambiental, se presenta su ciclo biogeoquímico, las fuentes naturales y antropogénicas, y sus efectos sobre las plantas y el medio ambiente. Seguidamente se presentan las principales respuestas moleculares de las plantas como señales de alarma temprana del daño generado por Cd y se propone su uso en el monitoreo de la contaminación por este metal.