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An Indonesian endophytic fungus Talaromyces veruculosus BioMCC-f.EP.2165, was cultured to find compounds that showing inhibitory activity against Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH). Preliminary extraction test (PET) was conducted for examination of active compounds properties in fungal culture broth. Active compounds were extracted and purified based on a method derived from PET result. We isolated altenusin as an active compound from the fungal culture extract. Although, altenusin has been reported previously as an inhibitor of PfDHODH and inhibited the proliferation of Plasmodium falciparum 3D7, we isolated this compound from endophytic Talaromyces fungus for the first time.

Macropinocytosis is an evolutionarily conserved endocytic process that plays a vital role in internalizing extracellular fluids and particles in cells. This non-selective endocytic pathway is crucial for various physiological functions such as nutrient uptake, sensing, signaling, antigen presentation, and cell migration. While macropinocytosis has been extensively studied in macrophages and cancer cells, the molecular mechanisms of macropinocytosis in pathogens are less understood. It has been known that Entamoeba histolytica, the causative agent of amebiasis, exploits macropinocytosis for survival and pathogenesis. Since macropinocytosis is initiated by actin polymerization, leading to the formation of membrane ruffles and the subsequent trapping of solutes in macropinosomes, actin cytoskeleton regulation is crucial. Thus, this study focuses on unraveling the role of well-conserved actin cytoskeleton regulators, Rho small GTPase family proteins, in macropinocytosis in E. histolytica. Through gene silencing of highly transcribed Ehrho/Ehrac genes and following flow cytometry analysis, we identified that silencing EhracM enhances dextran macropinocytosis and affects cellular migration persistence. Live imaging and interactome analysis unveiled the cytosolic and vesicular localization of EhRacM, along with its interaction with signaling and membrane traffic-related proteins, shedding light on EhRacM's multiple roles. Our findings provide insights into the specific regulatory mechanisms of macropinocytosis among endocytic pathways in E. histolytica, highlighting the significance of EhRacM in both macropinocytosis and cellular migration. Author summary: Entamoeba histolytica is an intestinal protozoan parasite that causes amoebic dysentery and liver abscesses in humans. This organism exploits macropinocytosis, a cellular process that engulfs extracellular fluids and particles, for its survival and pathogenicity. Although macropinocytosis is well-characterized in immune cells and cancer cells as it is essential for nutrient uptake, its mechanisms in pathogens, such as E. histolytica, remain less explored. Our research focused on the molecular mechanisms underpinning macropinocytosis in this parasite, specifically examining the role of Rho small GTPase family proteins. These proteins are critical regulators of the actin cytoskeleton in eukaryotic cells. Our study reveals that one specific Rho small GTPase, EhRacM, is in the maturation of macropinosomes as well as in directing linear cell migration. The physiological significance of EhRacM in regulating both macropinocytosis and migration opens new avenues for understanding the role of Rho small GTPases in these signaling pathways, which could eventually lead to the development of new control measures against diseases caused by this parasite. [ABSTRACT FROM AUTHOR]

Tetraspanins (TSPANs) are a family of proteins highly conserved in all eukaryotes. Although protein-protein interactions of TSPANs have been well established in eukaryotes including parasitic protists, the role they play in parasitism and pathogenesis remains largely unknown. In this study, we characterized three representative members of TSPANs, TSPAN4, TSPAN12, and TSPAN13 from the human intestinal protozoan Entamoeba histolytica. Co-immunoprecipitation assays demonstrated that TSPAN4, TSPAN12 and TSPAN13 are reciprocally pulled down together with several other TSPAN-interacting proteins including TSPAN binding protein of 55kDa (TBP55) and interaptin. Blue native-PAGE analysis showed that these TSPANs form several complexes of 120–250 kDa. Repression of tspan12 and tspan13 gene expression led to decreased secretion of cysteine proteases, while repression of tspan4 led to a four-fold increase in the activity of cysteine proteases in crude extracellular vesicles (EVs) fraction. Meanwhile, strains overexpressing HA-tagged TSPAN12 and TSPAN13 demonstrated reduced adhesion to collagen. Altogether, this study reveals that the TSPANs, especially TSPAN12 and TSPAN13, are engaged with complex protein-protein interactions and are involved in the pathogenicity-related biological functions such as protease secretion and adhesion, offering insights into the potential regulatory mechanisms of tetraspanins in protozoan parasites. Author summary: Tetraspanins (TSPANs) are involved in critical roles such as cellular communication, adhesion, and immune responses. However, their function in parasitic protozoa, particularly in relation to disease-causing mechanisms, remains poorly understood. Our study explores the role of three tetraspanins (TSPAN4, TSPAN12, and TSPAN13) in Entamoeba histolytica, an intestinal parasite which causes amebiasis, and a significant health problem affecting millions of people worldwide. Our findings reveal that these amebic TSPANs form various protein complexes similar to what is observed in other organisms. We also found that amebic TSPANs influence crucial processes related to the parasite's pathogenicity, such as adhesion to collagen and secretion of cysteine proteases (CPs). Gene silencing of TSPAN12 and TSPAN13 caused reduction in CP secretion, while overexpression resulted in decreased adhesion. Additionally, TSPAN4 appears to play a distinct role in exosome-mediated pathways. Our findings provide insights into a potential alternative mechanism of CP secretion via exosomes, in which amebic TSPANs may play a role. [ABSTRACT FROM AUTHOR]

Background: Malaria remains a significant global health burden, with drug resistance posing a major challenge to its control. The emergence of resistance to antimalarial drugs represents a critical issue in malaria management, as it heightens the likelihood of morbidity and mortality associated with the disease. There is an urgent requirement for a novel candidate drug with a distinct mechanism of action. Aim: In light of the ongoing challenges in malaria management, particularly the emergence of drug resistance, this study aimed to investigate the efficacy of a novel combination therapy of borrelidin and fumagilin against Plasmodium berghei infection on Swiss Webster mice. The findings of this study could contribute to developing new and effective antimalarial treatments. Methods: This study employed a unique approach, using Swiss Webster mice aged 6–8 weeks and dividing them into five groups, each with five mice. The therapeutic efficacy of the combination treatment was evaluated through a comprehensive assessment of parasitemia levels, survival rates, and histological changes in the liver and spleen. This rigorous methodology ensures the reliability and validity of our findings. Results: The combination of borrelidin and fumagilin led to the lowest parasitemia at 5%, contrasting with the control group reaching 15%. Moreover, the combination group exhibited the highest inhibition rate of 69.6% on day nine postinfection. Histopathological alterations were limited to sinusoid dilation, hepatocyte ballooning, and the presence of hemozoin. Conclusion: These findings suggest that the combination of borrelidin and fumagilin holds promise as a potential antimalarial therapy. [ABSTRACT FROM AUTHOR]