Electro-immunosensor for ultra-sensitive determination of cardiac troponin I based on reduced graphene oxide and polytyramine.

This work reports the construction of a novel nanostructured immunosensor for detection of the troponin I biomarker (cTnI). Anti-troponin I antibody was anchored on the modified graphite electrode with reduced graphene oxide and polytyramine for detection of troponin I in serum samples. The performance of the electro-immunosensor was evaluated by differential pulse voltammetry. The immunosensor presented a wide work range, from 4 ng mL-1 to 4 pg mL-1 , whose detection limit (4 pg mL-1 ) is significantly lower than the basal level in human serum, and maintained 100% of response after 30 days of storage. Moreover, the immunosensor showed good selectivity for detection of cTnI in real sample containing interfering substances and specificity of response to cTnI in the serum of healthy and sick patients, and demonstrated the possibility of reuse for two consecutive analyses, in addition to using a simplified and inexpensive platform when compared to other devices, demonstrating them excellent potential for application in diagnosis in the early stages of acute myocardial infarction.

Zinc Starvation Induces Cell Wall Remodeling and Activates the Antioxidant Defense System in Fonsecaea pedrosoi.

The survival of pathogenic fungi in the host after invasion depends on their ability to obtain nutrients, which include the transition metal zinc. This essential micronutrient is required to maintain the structure and function of various proteins and, therefore, plays a critical role in various biological processes. The host's nutritional immunity limits the availability of zinc to pathogenic fungi mainly by the action of calprotectin, a component of neutrophil extracellular traps. Here we investigated the adaptive responses of Fonsecaea pedrosoi to zinc-limiting conditions. This black fungus is the main etiological agent of chromoblastomycosis, a chronic neglected tropical disease that affects subcutaneous tissues. Following exposure to a zinc-limited environment, F. pedrosoi induces a high-affinity zinc uptake machinery, composed of zinc transporters and the zincophore Pra1. A proteomic approach was used to define proteins regulated by zinc deprivation. Cell wall remodeling, changes in neutral lipids homeostasis, and activation of the antioxidant system were the main strategies for survival in the hostile environment. Furthermore, the downregulation of enzymes required for sulfate assimilation was evident. Together, the adaptive responses allow fungal growth and development and reveals molecules that may be related to fungal persistence in the host.

The influence of a copper efflux pump in Histoplasma capsulatum virulence.

During the infectious process, pathogenic microorganisms must obtain nutrients from the host in order to survive and proliferate. These nutritional sources include the metallic nutrient copper. Despite its essentiality, copper in large amounts is toxic. Host defense mechanisms use high copper poisoning as a fungicidal strategy to control infection. Transcriptional analyses showed that yeast cultured in the presence of copper or inside macrophages (24 h) had elevated expression of CRP1, a copper efflux pump, suggesting that Histoplasma capsulatum could be exposed to a high copper environment in macrophages during the innate immune stage of infection. Accordingly, macrophages cultured in high copper are more efficient in controlling H. capsulatum growth. Also, silencing of ATP7a, a copper pump that promotes the copper influx in phagosomes, increases fungal survival in macrophages. The rich copper environment faced by the fungus is not dependent on IFN-γ, since fungal CRP1 expression is induced in untreated macrophages. Appropriately, CRP1 knockdown fungal strains are more susceptible to macrophage control than wild-type yeasts. Additionally, CRP1 silencing decreases fungal burden in mice during the phase of innate immune response (4-day postinfection) and CRP1 is required for full virulence in a macrophage cell lines (J774 A.1 and RAW 264.7), as well as primary cells (BMDM). Thus, induction of fungal copper detoxifying genes during innate immunity and the attenuated virulence of CRP1-knockdown yeasts suggest that H. capsulatum is exposed to a copper-rich environment at early infection, but circumvents this condition to establish infection.

Exposure of Paracoccidioides brasiliensis to Mebendazole Leads to Inhibition of Fungal Energy Production.

Paracoccidioidomycosis (PCM) is a fungal disease caused by organisms of the genus Paracoccidioides spp. The treatment of the disease is lengthy and includes several adverse effects. Various methodologies focus on the search for new treatments against fungal disease, including the repositioning of drugs. Our group showed the fungicidal effect of mebendazole in P. brasiliensis cells. Thus, understanding the effect of exposing fungal cells to mebendazole is significant for further studies in order to demonstrate it as a potential drug for the treatment of PCM. A proteomic analysis of P. brasiliensis exposed to mebendazole was carried out. Analyses showed that exposure strongly affected the pathways related to energy production, such as glycolysis, fermentation, and the electron transport chain. The quantification of adenosine triphosphate (ATP) and mitochondrial activity demonstrated that the drug alters the electron chain, resulting in an increase in oxidative stress. Enzymes such as superoxide dismutase (SOD) and cytochrome c oxidase (Cyt C) were repressed in cells exposed to mebendazole. The concentration of ethanol produced by the cells under treatment demonstrated that the attempt to produce energy through fermentation is also arrested. Thus, the drug inhibits fungal growth through changes in energy metabolism, making it a promising compound for use in the treatment of PCM.

Iron Starvation Induces Ferricrocin Production and the Reductive Iron Acquisition System in the Chromoblastomycosis Agent Cladophialophora carrionii.

Iron is a micronutrient required by almost all living organisms. Despite being essential, the availability of this metal is low in aerobic environments. Additionally, mammalian hosts evolved strategies to restrict iron from invading microorganisms. In this scenario, the survival of pathogenic fungi depends on high-affinity iron uptake mechanisms. Here, we show that the production of siderophores and the reductive iron acquisition system (RIA) are employed by Cladophialophora carrionii under iron restriction. This black fungus is one of the causative agents of chromoblastomycosis, a neglected subcutaneous tropical disease. Siderophore biosynthesis genes are arranged in clusters and, interestingly, two RIA systems are present in the genome. Orthologs of putative siderophore transporters were identified as well. Iron starvation regulates the expression of genes related to both siderophore production and RIA systems, as well as of two transcription factors that regulate iron homeostasis in fungi. A chrome azurol S assay demonstrated the secretion of hydroxamate-type siderophores, which were further identified via RP-HPLC and mass spectrometry as ferricrocin. An analysis of cell extracts also revealed ferricrocin as an intracellular siderophore. The presence of active high-affinity iron acquisition systems may surely contribute to fungal survival during infection.

High copper promotes cell wall remodeling and oxidative stress in Histoplasma capsulatum, as revealed by proteomics.

Histoplasma experiences nutritional stress during infection as a result of immune cells manipulating essential nutrients, such as metal ions, carbon, nitrogen, and vitamins. Copper (Cu) is an essential metallic micronutrient for living organisms; however, it is toxic in excess. Microbial pathogens must resist copper toxicity to survive. In the case of Histoplasma, virulence is supported by high-affinity copper uptake during late infection, and copper detoxification machinery during early macrophage infection. The objective of this study was to characterize the global molecular adaptation of Histoplasma capsulatum to copper excess using proteomics. Proteomic data revealed that carbohydrate breakdown was repressed, while the lipid degradation pathways were induced. Surprisingly, the production of fatty acids/lipids was also observed, which is likely a result of Cu-mediated damage to lipids. Additionally, the data showed that the fungus increased the exposition of glycan and chitin on the cell surface in high copper. Yeast upregulated antioxidant enzymes to counteract ROS accumulation. The induction of amino acid degradation, fatty acid oxidation, citric acid cycle, and oxidative phosphorylation suggest an increase in aerobic respiration for energy generation. Thus, H. capsulatum's adaptive response to high Cu is putatively composed of metabolic changes to support lipid and cell wall remodeling and fight oxidative stress.

Fonsecaea pedrosoi produces ferricrocin and can utilize different host iron sources.

The survival of living organisms depends on iron, one of the most abundant metals in the Earth's crust. Nevertheless, this micronutrient is poorly available in our aerobic atmosphere as well as inside the mammalian host. This problem is circumvented by the expression of high affinity iron uptake machineries, including the production of siderophores, in pathogenic fungi. Here we demonstrated that F. pedrosoi, the causative agent of the neglected tropical disease chromoblastomycosis, presents gene clusters for siderophore production. In addition, ten putative siderophore transporters were identified. Those genes are upregulated under iron starvation, a condition that induces the secretion of hydroxamates, as revealed by chrome azurol S assays. RP-HPLC and mass spectrometry analysis allowed the identification of ferricrocin as an intra- and extracellular siderophore. F. pedrosoi can grow in different iron sources, including the bacterial ferrioxamine B and the host proteins ferritin, hemoglobin and holotransferrin. Of note, addition of hemoglobin, lactoferrin and holotransferrin to the growth medium of macrophages infected with F. pedrosoi enhanced significantly fungal survival. The ability to produce siderophores in iron limited conditions added to the versatility to utilize different sources of iron are strategies that certainly may contribute to fungal survival inside the host.

Molecular Interactions of the Copper Chaperone Atx1 of Paracoccidioides brasiliensis with Fungal Proteins Suggest a Crosstalk between Iron and Copper Homeostasis.

Paracoccidioides spp. are endemic fungi from Latin America that cause Paracoccidioidomycosis, a systemic disease. These fungi present systems for high-affinity metal uptake, storage, and mobilization, which counteract host nutritional immunity and mitigate the toxic effects of metals. Regarding Cu mobilization, the metallochaperone Atx1 is regulated according to Cu bioavailability in Paracoccidioides spp., contributing to metal homeostasis. However, additional information in the literature on PbAtx1 is scarce. Therefore, in the present work, we aimed to study the PbAtx1 protein-protein interaction networks. Heterologous expressed PbAtx1 was used in a pull-down assay with Paracoccidioides brasiliensis cytoplasmic extract. Nineteen proteins that interacted with PbAtx1 were identified by HPLC-MSE. Among them, a relevant finding was a Cytochrome b5 (PbCyb5), regulated by Fe bioavailability in Aspergillus fumigatus and highly secreted by P. brasiliensis in Fe deprivation. We validated the interaction between PbAtx1-PbCyb5 through molecular modeling and far-Western analyses. It is known that there is a relationship between Fe homeostasis and Cu homeostasis in organisms. In this sense, would PbAtx1-PbCyb5 interaction be a new metal-sensor system? Would it be supported by the presence/absence of metals? We intend to answer those questions in future works to contribute to the understanding of the strategies employed by Paracoccidioides spp. to overcome host defenses.

New Methylcitrate Synthase Inhibitor Induces Proteolysis, Lipid Degradation and Pyruvate Excretion in Paracoccidioides brasiliensis.

BACKGROUND: Paracoccidioidomycosis is a systemic mycosis caused by the inhalation of conidia of the genus Paracoccidioides. During the infectious process, fungal cells use several carbon sources, leading to the production of propionyl-CoA. The latter is metabolized by the methylcitrate synthase, a key enzyme of the methylcitrate cycle. We identified an inhibitor compound (ZINC08964784) that showed antifungal activity against P. brasiliensis. METHODS: This work aimed to understand the fungal metabolic response of P. brasiliensis cells exposed to ZINC08964784 through a proteomics approach. We used a glucose-free medium supplemented with propionate in order to simulate the environment found by the pathogen during the infection. We performed pyruvate dosage, proteolytic assay, dosage of intracellular lipids and quantification of reactive oxygen species in order to validate the proteomic results. RESULTS: The proteomic analysis indicated that the fungal cells undergo a metabolic shift due to the inhibition of the methylcitrate cycle and the generation of reactive species. Proteolytic enzymes were induced, driving amino acids into degradation for energy production. In addition, glycolysis and the citric acid cycle were down-regulated while ß-oxidation was up-regulated. The accumulation of pyruvate and propionyl-CoA led the cells to a state of oxidative stress in the presence of ZINC08964784. CONCLUSIONS: The inhibition of methylcitrate synthase caused by the compound promoted a metabolic shift in P. brasiliensis damaging energy production and generating oxidative stress. Hence, the compound is a promising alternative for developing new strategies of therapies against paracoccidioidomycosis.

A highly reusable genosensor for late-life depression diagnosis based on microRNA 184 attomolar detection in human plasma.

Late-Life Depression (LLD) is one of the most prevalent psychiatric disorders in elderly, causing significant functional impairments. MicroRNAs are small molecules involved in the post-transcriptional regulation of gene expression. Elderly individuals diagnosed with LLD present down regulation of miR-184 (hsa-miR-184) expression compared to healthy patients. Therefore, this miR-184 can be used as a biomarker to diagnose LLD. Current LLD diagnosis depends primarily on clinical subjective identification, based on symptoms and variable scales. This work introduces a novel and facile approach for the LLD diagnosis based on the development of an electrochemical genosensor for miR-184 detection in plasma, using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). DPV results presented a 2-Fold increase in current value for healthy patients, compared to individuals with LLD when monitoring ethidium bromide oxidation peak. For EIS, a 1.5-fold increase in charge transfer resistance for healthy elderly subjects was observed in comparison with depressed patients. In addition, the analytical performance of the biosensor was evaluated using DPV, obtaining a linear response ranging from 10-9 mol L-1 to 10-17 mol L-1 of miR-184 in plasma and a detection limit of 10 atomoles L-1. The biosensor presented reusability, selectivity and stability, the current response remained 72% up to 50 days of storage. Thus, the genosensor proved to be efficient in the diagnosis of LLD, as well as the accurate quantification of miR-184 in real plasma samples of healthy and depressed patients.

Proteomic analysis reveals changes in the proteome of human THP-1 macrophages infected with Paracoccidioides brasiliensis.

Paracoccidioides spp. is the etiologic agent of Paracoccidioidomycosis (PCM), a systemic disease with wide distribution in Latin America. Macrophages are very important cells during the response to infection by P. brasiliensis. In this study, we performed a proteomic analysis to evaluate the consequences of P. brasiliensis yeast cells on the human THP-1 macrophage proteome. We have identified 443 and 2247 upregulated or downregulated proteins, respectively, in macrophages co-cultured with yeast cells of P. brasiliensis in comparison to control macrophages unexposed to the fungus. Proteomic analysis revealed that interaction with P. brasiliensis caused metabolic changes in macrophages that drastically affected energy production pathways. In addition, these macrophages presented regulated many factors related to epigenetic modifications and gene transcription as well as a decrease of many proteins associated to the immune system activity. This is the first human macrophage proteome derived from interactions with P. brasiliensis, which contributes to elucidating the changes that occur during the host response to this fungus. Furthermore, it highlights proteins that may be targets for the development of new therapeutic approaches to PCM.

Seropositivity to Cysticercosis in School-Age Children Living in a Low-Income Municipality in the Midwest Region of Brazil.

Background: Human cysticercosis (CC) is a global public health problem, especially in Latin America, including Brazil. We aimed to analyze the seroprevalence of CC among school-age children and adolescents. Methods: We analyzed the presence of specific IgG antibodies against Taenia solium metacestodes in 500 serum samples from elementary school children and adolescents in Jataí City, state of Goiás, Brazil. IgG antibodies against the antigenic extract of the parasite were detected and analyzed by ELISA, and specific peptides were identified by confirmatory Western Blotting test. Results: Of the 500 study participants, 205 (41%) were male, and 295 (59%) were female. Participants aged between 4 and 18 years (mean age 8.4 years). The percentage of serum samples reactive by ELISA was 37.2%. These samples were analyzed by Western Blotting, which confirmed that the seropositivity rate was 6.2% (95% CI 2.4-14.7) in 31 samples reactive for CC-specific bands, determined in serum samples from 18 male (5-11 years old) and 13 female (4-12 years old) students. Conclusion: The CC seroprevalence demonstrated in schoolchildren suggests that this parasitosis is endemic in the study area. Further investigations are necessary to clarify the local epidemiology of this parasitosis.

Proteomic alterations in Paracoccidioides brasiliensis caused by exposure to curcumin.

Paracoccidioides spp. are the etiological agent of paracoccidioidomycosis, a disease that causes skin lesions and affect the lungs and other organs. The current management of the disease is long and has several side effects that often lead the patient to give up the treatment, sequelae and even death. The search for new forms of treatment that minimize these drawbacks is very important. Thus, natural compounds are targets of great interest. Curcumin is one of the main components of the tubers of Curcuma longa, presenting medicinal effects well described in the literature, including the antifungal effect on Paracocidioides brasiliensis. Nevertheless, the mechanisms related to the antifungal effect of such compound are still unknown, so the objective of the present research is to understand what changes occur in the metabolism of P. brasiliensis after exposure to curcumin and to identify the main targets of the compound. Proteomic analysis as based on nanoUPLC-MS analysis and the functional classification of the identified proteins. The main metabolic processes that were being regulated were biologically validated through assays such as fluorescence microscopy, EPR and phagocytosis. Proteomic analysis revealed that curcumin regulates several metabolic processes of the fungus, including important pathways for energy production, such as the glycolytic pathway, beta oxidation and the glyoxylate cycle. Protein synthesis was down-regulated in fungi exposed to curcumin. The electron transport chain and the tricarboxylic acid cycle were also down-regulated, indicating that both the mitochondrial membrane and the mitochondrial activity were compromised. Plasma membrane and cell wall structure were altered following exposure to the compound. The fungus' ability to survive the phagocytosis process by alveolar macrophages was reduced. Thus, curcumin interferes with several metabolic pathways in the fungus that causes paracoccidioidomycosis. BIOLOGICAL SIGNIFICANCE: The challenges presented by the current treatment of paracoccidioidomycosis often contributing to patients' withdrawal from treatment, leading to sequelae or even death. Thus, the search for new treatment options against this disease is growing. The discovery that curcumin is active against Paracoccidioides was previously reported by our study group. Here, we clarify how the compound acts on the fungus causing its growth inhibition and decreased viability. Understanding the mechanisms of action of curcumin on P. brasiliensis elucidates how we can seek new alternatives and which metabolic pathways and molecular targets we should focus on in this incessant search to bring the patient a treatment with fewer adverse effects.

Bioluminescence imaging in Paracoccidioides spp.: a tool to monitor the infectious processes.

The genus Paracoccidioides comprises the species complex causing paracoccidioidomycoses (PCM). These fungi are a serious public health problem due to the long-term drug therapy, follow-up treatment, and frequent sequelae generated by the infection, such as pulmonary fibrosis. In this sense, the objective of this work was to generate bioluminescent reporter strains of Paracoccidioides spp. harboring a thermostable, red-shifted luciferase gene under the control of different constitutive promoters. The strains were generated by the integration of a species-specific codon-optimized luciferase gene upon actin or enolase promoter's control. The insertion of the constructs in Paracoccidioides brasiliensis and Paracoccidioides lutzii yeast cells were performed through Agrobacterium tumefaciens-mediated transformation. The results demonstrated the presence of several transformants harboring the luciferase gene. These transformants were further confirmed by the expression of luciferase and by the presence of the hygromycin resistance gene. Moreover, the luciferase activity could be detected in in vitro bioluminescence assays and in vivo models of infection. In general, this work presents the methodology for the construction of bioluminescent strains of Paracoccidioides spp., highlighting potential promoters and proposing an in vivo model, in which those strains could be used for the systemic study of PCM.

Ninhydrin as a novel DNA hybridization indicator applied to a highly reusable electrochemical genosensor for Candida auris.

This work reports a simple strategy for Candida auris genomic DNA (gDNA) detection, a multi-resistant fungus associated with nosocomial outbreaks in healthcare settings, presenting high mortality and morbidity rates. The platform was developed using gold electrode sensitized with specific DNA capture probe and ninhydrin as a novel DNA hybridization indicator. The genosensor was able to detect C. auris in urine sample by differential pulse voltammetry and electrochemical impedance spectroscopy. The biosensor's analytical performance was evaluated by differential pulse voltammetry, detecting up to 4.5 pg µL-1 of C. auris gDNA in urine (1:10, V/V). Moreover, the genosensor was reused eight times with no loss in the current signal response. The genosensor showed selectivity and stability, maintaining 100% of its response up to 80 days of storage. In order to analyze interactions of single and double-stranded DNA with ninhydrin, SEM, AFM and molecular dynamics studies followed by docking simulations were performed. Theoretical calculations showed ninhydrin interactions more favorably with dsDNA in an A-T rich binding pocket rather than with the ssDNA. Therefore, the proposed system is a promising electrochemical detection device towards a more accurate detection of C. auris gDNA in biological samples.

Insights Into Histoplasma capsulatum Behavior on Zinc Deprivation.

Histoplasma capsulatum is a thermodimorphic fungus that causes histoplasmosis, a mycosis of global incidence. The disease is prevalent in temperate and tropical regions such as North America, South America, Europe, and Asia. It is known that during infection macrophages restrict Zn availability to H. capsulatum as a microbicidal mechanism. In this way the present work aimed to study the response of H. capsulatum to zinc deprivation. In silico analyses showed that H. capsulatum has eight genes related to zinc homeostasis ranging from transcription factors to CDF and ZIP family transporters. The transcriptional levels of ZAP1, ZRT1, and ZRT2 were induced under zinc-limiting conditions. The decrease in Zn availability increases fungicidal macrophage activity. Proteomics analysis during zinc deprivation at 24 and 48 h showed 265 proteins differentially expressed at 24 h and 68 at 48 h. Proteins related to energy production pathways, oxidative stress, and cell wall remodeling were regulated. The data also suggested that low metal availability increases the chitin and glycan content in fungal cell wall that results in smoother cell surface. Metal restriction also induces oxidative stress triggered, at least in part, by reduction in pyridoxin synthesis.

In vitro ovicidal and larvicidal activity of Carica papaya seed hexane extract against Strongyloides venezuelensis.

Strongyloidiasis is a human parasitic disease caused by the helminth Strongyloides stercoralis whose treatment is particularly difficult in immunosuppressed patients due to their low responsiveness to conventional therapy. Carica papaya and its isolated compounds benzyl isothiocyanate, carpaine and carpasemine are promising compound for the treatment of Strongyloides infections due to their anthelmintic action. This study aims to examine the in vitro ovicidal and larvicidal activity of C. papaya seed hexane extract against Strongyloides venezuelensis, using egg hatching tests and larval motility tests as efficiency markers. The crude extract at the concentrations of 566 - 0.0566 mg/mL or the control with albendazole (0.025 mg/mL) and negative controls (water and PBS) were incubated with an equal volume of egg suspension (± 50 specimens) followed by counting of the specimens after 48 h. The same extract and dilutions were added to L3 larvae suspensions (±50 specimens) followed by analysis of larvae viability after 24, 48, and 72 h. The extract inhibited egg hatching with high efficiency at concentrations of 56.6 mg/mL (95.74%) and 5.66 mg/mL (92.16%). At the concentrations of 566 mg/mL (100%) and 56.66 mg/mL (97.32%), the extract inhibited larval motility as effectively as ivermectin (0.316 mg/mL; 100%), and more effectively than the other dilutions and the negative controls. The larvicidal effect depended on the extract concentration, but not on the treatment period. Therefore, C. papaya seed hexane extract has anthelmintic potential against S. venezuelensis and is a promising compound for the development of phytotherapies to treat strongyloidiasis.

A novel research model for evaluating sunscreen protection in the UV-A1.

The use of a broad spectrum sunscreen is considered one of the main and most popular measures for preventing the damaging effects of ultraviolet radiation (UVR) on the skin. In this study we have developed a novel in vitro method to assess sunscreens efficacy to protect calcineurin enzyme activity, a skin cell marker. The photoprotective efficacy of sunscreen products was assessed by measuring the UV-A1 radiation-induced depletion of calcineurin (Cn) enzyme activity in primary neonatal human dermal fibroblast (HDFn) cell lysates. After exposure to 24J/cm2 UV-A1 radiation, the sunscreens containing larger amounts of UV-A1 filters (brand B), the astaxanthin (UV-A1 absorber) and the Tinosorb® M (UV-A1 absorber) were capable of preventing loss of Cn activity when compared to the sunscreens formulations of brand A (low concentration of UV-A1 filters), with the Garcinia brasiliensis extract (UV-B absorber) and with the unprotected cell lysate and exposed to irradiation (Irradiated Control - IC). The Cn activity assay is a reproducible, accurate and selective technique for evaluating the effectiveness of sunscreens against the effects of UV-A1 radiation. The developed method showed that calcineurin activity have the potential to act as a biological indicator of UV-A1 radiation-induced damages in skin and the assay might be used to assess the efficacy of sunscreens agents and plant extracts prior to in vivo tests.

In vitro efficacy of latex and purified papain from Carica papaya against Strongyloides venezuelensis eggs and larvae.

Latex from Carica papaya is rich in bioactive compounds, especially papain, which may help to control parasitic diseases. This study evaluated the efficacy of latex from C. papaya and purified papain against Strongyloides venezuelensis. The Egg Hatching Test (EHT) and the Larval Motility Test (LMT) using fresh and frozen latex (250mg/mL), lyophilized latex (34mg/mL), and purified papain (2.8 mg/mL) were performed. Albendazole (0.025 mg/mL) and ivermectin (316 ppm) were used as positive controls. EHT and LMT were carried out through the incubation of each solution with S. venezuelensis eggs or larvae (± 100 specimens), and results were analyzed after 48h (EHT) or 24, 48, and 72h (LMT). EHT showed that latex preparations at higher concentrations (1:10 to 1:100) resulted in partial or complete destruction of eggs and larvae inside the eggs. The result from the 1:1,000 dilution was similar to the positive control. LMT showed effectiveness in all the tested dilutions compared to negative controls. Purified papain showed a dose-dependent response in the EHT. Purified papain (2.8 mg/ mL) showed similar results to lyophilized latex at 1:1,000 in the EHT. Latex and purified papain from C. papaya were effective against S. venezuelensis eggs and larvae in vitro, suggesting their potential use as an alternative treatment for strongyloidiasis.

In vitro efficacy of latex and purified papain from Carica papaya against Strongyloides venezuelensis eggs and larvae

ABSTRACT Latex from Carica papaya is rich in bioactive compounds, especially papain, which may help to control parasitic diseases. This study evaluated the efficacy of latex from C. papaya and purified papain against Strongyloides venezuelensis. The Egg Hatching Test (EHT) and the Larval Motility Test (LMT) using fresh and frozen latex (250mg/mL), lyophilized latex (34mg/mL), and purified papain (2.8 mg/mL) were performed. Albendazole (0.025 mg/mL) and ivermectin (316 ppm) were used as positive controls. EHT and LMT were carried out through the incubation of each solution with S. venezuelensis eggs or larvae (± 100 specimens), and results were analyzed after 48h (EHT) or 24, 48, and 72h (LMT). EHT showed that latex preparations at higher concentrations (1:10 to 1:100) resulted in partial or complete destruction of eggs and larvae inside the eggs. The result from the 1:1,000 dilution was similar to the positive control. LMT showed effectiveness in all the tested dilutions compared to negative controls. Purified papain showed a dose-dependent response in the EHT. Purified papain (2.8 mg/ mL) showed similar results to lyophilized latex at 1:1,000 in the EHT. Latex and purified papain from C. papaya were effective against S. venezuelensis eggs and larvae in vitro, suggesting their potential use as an alternative treatment for strongyloidiasis.