Amoebae Research Articles

Three-dimensional simulation of obstacle-mediated chemotaxis.

Amoeboid cells exhibit a highly dynamic motion that can be directed by external chemical signals, through the process of chemotaxis. Here, we propose a three-dimensional model for chemotactic motion of amoeboid cells. We account for the interactions between the extracellular substances, the membrane-bound proteins, and the cytosolic components involved in the signaling pathway that originates cell motility. We show two- and three-dimensional simulations of cell migration on planar substrates, flat surfaces with obstacles, and fibrous networks. The results show that our model reproduces the main features of chemotactic amoeboid motion. Our simulations unveil a complicated interplay between the geometry of the cell's environment and the chemoattractant dynamics that tightly regulates cell motion. The model opens new opportunities to simulate the interactions between extra- and intra-cellular compounds mediated by the matrix geometry.

Prenatal Maternal Immune Activation Sensitizes the Neuroinflammatory Responses to Neonatal Hypoxic-Ischemic Brain Injury

Abstract Epidemiological evidence suggests that prenatal maternal immune activation (MIA) is a risk factor for autism spectrum disorders (ASD). Yet, because not all human MIA offspring develop ASD, we hypothesize that “second hits” may be needed to induce severe brain damage and disruption of the neural network. We tested this hypothesis using an established MIA model with Poly I:C (20 mg/kg) intraperitoneally injected at mid pregnancy (E12.5) in C57BL/6 mice. The offspring were challenged by mild hypoxia-ischemia (HI) at P10 as the second hit. We found that MIA alone infrequently caused clusters of amoeboid microglial cells (AMCs) expressing a high level of Complement component 3 (C3) in the offspring brains. Elevated NFkB signaling and a higher basal level of IL-6, IL-17 and MMP9 mRNA were also detected in the P11 MIA offspring brains. When challenged by HI, the MIA offspring showed significantly greater NFkB activity, TUNEL-positive apoptosis, and mRNAs for pro-inflammatory cytokines including IL-6, IL-17, TNFα, IL-23, TSPO and MCP-1 at 24 h post-injury, when compared to those injured by HI alone. At 7 d recovery, the MIA/HI-injured mice showed more AMCs, monocyte infiltration, and greater brain atrophy than singularly MIA- or HI-injured mice. Finally, the MIA/HI-injured mouse brains showed a significant reduction of PSD95 and synaptotagmin/PSD-96 punctates, correlated with greater C3 expression in the hippocampal CA2/3 region than MIA alone or HI-injured counterparts. Together, these results suggest that MIA elevates the inflammatory activity in the offspring brain, and acts as a primer to sensitize the neuroinflammatory responses to a secondary insult, leading to greater brain damage, and potentially ASD-like cognitive deficits.

Design of a rotating disk reactor to assess the colonization of biofilms by free-living amoebae under high shear rates

The present study was aimed at designing and optimizing a rotating disk reactor simulating high hydrodynamic shear rates (γ), which are representative of cooling circuits. The characteristics of the hydrodynamic conditions in the reactor and the complex approach used to engineer it are described. A 60 l tank was filled with freshwater containing free-living amoebae (FLA) and bacteria. Adhesion of the bacteria and formation of a biofilm on the stainless steel coupons were observed. FLA were able to establish in these biofilms under γ as high as 85,000 s−1. Several physical mechanisms (convection, diffusion, sedimentation) could explain the accumulation of amoeboid cells on surfaces, but further research is required to fully understand and model the fine mechanisms governing such transport under γ similar to those encountered in the industrial environment. This technological advance may enable research into these topics.

Automated Morphological Analysis of Microglia After Stroke.

Microglia are the resident immune cells of the brain and react quickly to changes in their environment with transcriptional regulation and morphological changes. Brain tissue injury such as ischemic stroke induces a local inflammatory response encompassing microglial activation. The change in activation status of a microglia is reflected in its gradual morphological transformation from a highly ramified into a less ramified or amoeboid cell shape. For this reason, the morphological changes of microglia are widely utilized to quantify microglial activation and studying their involvement in virtually all brain diseases. However, the currently available methods, which are mainly based on manual rating of immunofluorescent microscopic images, are often inaccurate, rater biased, and highly time consuming. To address these issues, we created a fully automated image analysis tool, which enables the analysis of microglia morphology from a confocal Z-stack and providing up to 59 morphological features. We developed the algorithm on an exploratory dataset of microglial cells from a stroke mouse model and validated the findings on an independent data set. In both datasets, we could demonstrate the ability of the algorithm to sensitively discriminate between the microglia morphology in the peri-infarct and the contralateral, unaffected cortex. Dimensionality reduction by principal component analysis allowed to generate a highly sensitive compound score for microglial shape analysis. Finally, we tested for concordance of results between the novel automated analysis tool and the conventional manual analysis and found a high degree of correlation. In conclusion, our novel method for the fully automatized analysis of microglia morphology shows excellent accuracy and time efficacy compared to traditional analysis methods. This tool, which we make openly available, could find application to study microglia morphology using fluorescence imaging in a wide range of brain disease models.

Emergence of collective propulsion through cell-cell adhesion.

The mechanisms driving the collective movement of cells remain poorly understood. To contribute toward resolving this mystery, a model was formulated to theoretically explore the possible functions of polarized cell-cell adhesion in collective cell migration. The model consists of an amoeba cell with polarized cell-cell adhesion, which is controlled by positive feedback with cell motion. This model cell has no persistent propulsion and therefore exhibits a simple random walk when in isolation. However, at high density, these cells acquire collective propulsion and form ordered movement. This result suggests that cell-cell adhesion has a potential function, which induces collective propulsion with persistence.

Mature and progenitor endothelial cells perform angiogenesis also under protease inhibition: the amoeboid angiogenesis

BackgroundControlling vascular growth is a challenging aim for the inhibition of tumor growth and metastasis. The amoeboid and mesenchymal types of invasiveness are two modes of migration interchangeable in cancer cells: the Rac-dependent mesenchymal migration requires the activity of proteases; the Rho-ROCK-dependent amoeboid motility is protease-independent and has never been described in endothelial cells.MethodsA cocktail of physiologic inhibitors (Ph-C) of serine-proteases, metallo-proteases and cysteine-proteases, mimicking the physiological environment that cells encounter during their migration within the angiogenesis sites was used to induce amoeboid style migration of Endothelial colony forming cells (ECFCs) and mature endothelial cells (ECs). To evaluate the mesenchymal-ameboid transition RhoA and Rac1 activation assays were performed along with immunofluorescence analysis of proteins involved in cytoskeleton organization. Cell invasion was studied in Boyden chambers and Matrigel plug assay for the in vivo angiogenesis.ResultsIn the present study we showed in both ECFCs and ECs, a decrease of activated Rac1 and an increase of activated RhoA upon shifting of cells to the amoeboid conditions. In presence of Ph-C inhibitors both cell lines acquired a round morphology and Matrigel invasion was greatly enhanced with respect to that observed in the absence of protease inhibition. We also observed that the urokinase-plasminogen-activator (uPAR) receptor silencing and uPAR-integrin uncoupling with the M25 peptide abolished both mesenchymal and amoeboid angiogenesis of ECFCs and ECs in vitro and in vivo, indicating a role of the uPAR-integrin-actin axis in the regulation of amoeboid angiogenesis. Furthermore, under amoeboid conditions endothelial cells seem to be indifferent to VEGF stimulation, which induces an amoeboid signaling pattern also in mesenchymal conditions.ConclusionHere we first provide a data set disclosing that endothelial cells can move and differentiate into vascular structures in vitro and in vivo also in the absence of proteases activity, performing a new type of neovascularization: the “amoeboid angiogenesis”. uPAR is indispensable for ECs and ECFCs to perform an efficient amoeboid angiogenesis. Therefore, uPAR silencing or the block of its integrin-interaction, together with standard treatment against VEGF, could be a possible solution for angiogenesis inhibition.

The cytoskeleton regulates symmetry transitions in moving amoeboid cells

Symmetry and symmetry breaking are essential in biology. Symmetry comes in different forms: rotational symmetry, mirror symmetry and alternating right-left symmetry (for example, gliding reflection symmetry). Especially the transitions between the different symmetry forms are important because they specify crucial points in cell biology, including gastrulation in development, formation of the cleavage furrow in cell division, or the front in cell polarity. However, the mechanisms of these symmetry transitions are not well understood. Here, we have investigated the fundamental properties of symmetry and symmetry transitions of the cytoskeleton during cell movement. Our data show that the dynamic shape changes of amoeboid cells are far from random, but are the consequence of refined symmetries and symmetry changes that are orchestrated by small G-proteins and the cytoskeleton, with local stimulation by F-actin and Scar, and local inhibition by IQGAP2 and myosin.

Bilateral early activation of retinal microglial cells in a mouse model of unilateral laser-induced experimental ocular hypertension

The immune system plays an important role in glaucomatous neurodegeneration. Retinal microglial reactivation associated with ganglion cell loss could reportedly contribute to the glaucoma progression. Recently we have described signs of microglia activation both in contralateral and ocular hypertension (OHT) eyes involving all retinal layers 15 days after OHT laser induction in mice. However, no works available have analyzed the microglial activation at earliest time points after OHT induction (24 h) in this experimental model. Thus, we seek to describe and quantify signs of microglia activation and differences depending on the retinal layer, 24 h after unilateral laser-induced OHT. Two groups of adult Swiss mice were used: age-matched control (naïve) and lasered. In the lasered animals, OHT eyes as well as contralateral eyes were analyzed. Retinal whole-mounts were immunostained with antibodies against Iba-1 and MHC-II. We quantified the number of microglial cells in the photoreceptor layer (OS), outer plexiform layer (OPL), and inner plexiform layer (IPL); the number of microglial vertical processes connecting the OPL and OS; the area of the retina occupied by Iba-1+ cells (Iba1-RA) in the nerve fiber layer-ganglion cell layer (NFL-GCL), the total arbor area of microglial cells in the OPL and IPL and; Iba-1+ cell body area in the OPL, IPL and NFL-GCL. In contralateral and OHT eyes the morphological features of Iba-1+ cell activation were: migration, enlargement of the cell body, higher degree of branching and reorientation of the processes, radial disposition of the soma and processes toward adjacent microglial plexuses, and presence of amoeboid cells acting as macrophages. These signs were more pronounced in OHT eyes. Most of Iba-1+ cells did not express MHC-II; rather, only dendritic and rounded cells expressed it. In comparison with naïve eyes, in OHT eyes and contralateral eyes no significant differences were found in the microglial cell number; but there was a significant increase in Iba1-RA. The total arbor area of microglial cells was significantly decreased in: i) OHT eyes with respect contralateral eyes and naïve-eyes in IPL; ii) OHT eyes with respect to naïve eyes in OPL. The number of microglial vertical processes connecting the OPL and OS were significantly increased in contralateral eyes compared with naïve-eyes and OHT eyes. In OPL, IPL and NFL-GCL, the cell body area of Iba-1+ cells was significantly greater in OHT eyes than in naïve and contralateral eyes, and greater in contralateral eyes than in naïve eyes. A non-proliferative microglial reactivation was detected both in contralateral eyes and in OHT eyes in an early time after unilateral laser-induced OHT (24 h). This fast microglial activation, which involves the contralateral eye, could be mediated by the immune system.

The Efficiency of Cultivation Media in Recovering Naked Lobose Amoebae from Freshwater Environments.

Martin Mrva and Mária Garajová (2018) This paper deals with the efficiency of cultivation media in recovering the species diversity of naked lobose amoebae. A total of 24 species belonging to ten families were isolated with six enrichment media (two liquid and four agar media) during a two-year study on naked lobose amoebae in a branch of the Danube River in Bratislava (Slovak Republic). The highest efficiency was seen in the grass-seed infusion, grass-seed agar, and non-nutrient agar, with 79%, 67%, and 58% of species recovered, respectively. The grass-seed infusion yielded the highest numbers of Thecamoebidae, Vannellidae, Mayorellidae and Dermamoebidae species and is likely the most suitable medium for their recovery. The most effective media were based on grass-seed infusions, which are easy to prepare and suitable for studying the diversity and ecology of naked amoebae from freshwater samples.

Morphology, biology and phylogeny of Phalansterium arcticum sp. n. (Amoebozoa, Variosea), isolated from ancient Arctic permafrost

A new species, Phalansterium arcticum sp. n., was isolated from an 8580-year-old Arctic permafrost layer. This organism typically lives as a sedentary uniflagellated cell enclosed in a thin flexible mucilaginous sheath, but can form naked swimming cells and amoeboid cells with eruptive pseudopodia accompanied with the formation of short, filopodia-like projections. In an SSU rDNA phylogenetic tree, it robustly groups with other species of this genus. Along with a description of the species, we also add new details to the description of the cell division of Phalansterium and the feeding process in this organism.

Ultrastructure of Sperm Development and Mature Sperm Morphology inSpondylus calciferandS. Princeps(Bivalvia: Spondylidae)

The entire spermatogenesis process and the presence of accessory cells in sperm development in Spondylus princeps Broderip, 1833, and S. calcifer Carpenter, 1857, were described for the first time. Spermatogenesis in both species showed similar anatomical and ultrastructural features. The testis contained amoeboid somatic cells inside the acini, frequently associated with developing gametes. Overall, spermatogenesis followed the typical pattern reported for other bivalve species, except for a few specific details. In S. princeps, intercellular bridges between spermatogonia, as well as one spermatocyte with seven mitochondria were observed. Both species had mature sperm of the ect-aquasperm type, consisting of a head, which contains a spherical-pyriform nucleus and a conical acrosome bounded by two regions of different density, four spherical mitochondria and two centrioles in the middle piece; the flagellum showed a standard 9 2 microtubule arrangement.

Evaluating Different Virulence Traits of Klebsiella pneumoniae Using Dictyostelium discoideum and Zebrafish Larvae as Host Models

Multiresistant and invasive hypervirulent Klebsiella pneumoniae strains have become one of the most urgent bacterial pathogen threats. Recent analyses revealed a high genomic plasticity of this species, harboring a variety of mobile genetic elements associated with virulent strains, encoding proteins of unknown function whose possible role in pathogenesis have not been addressed. K. pneumoniae virulence has been studied mainly in animal models such as mice and pigs, however, practical, financial, ethical and methodological issues limit the use of mammal hosts. Consequently, the development of simple and cost-effective experimental approaches with alternative host models is needed. In this work we described the use of both, the social amoeba and professional phagocyte Dictyostelium discoideum and the fish Danio rerio (zebrafish) as surrogate host models to study K. pneumoniae virulence. We compared three K. pneumoniae clinical isolates evaluating their resistance to phagocytosis, intracellular survival, lethality, intestinal colonization, and innate immune cells recruitment. Optical transparency of both host models permitted studying the infective process in vivo, following the Klebsiella-host interactions through live-cell imaging. We demonstrated that K. pneumoniae RYC492, but not the multiresistant strains 700603 and BAA-1705, is virulent to both host models and elicits a strong immune response. Moreover, this strain showed a high resistance to phagocytosis by D. discoideum, an increased ability to form biofilms and a more prominent and irregular capsule. Besides, the strain 700603 showed the unique ability to replicate inside amoeba cells. Genomic comparison of the K. pneumoniae strains showed that the RYC492 strain has a higher overall content of virulence factors although no specific genes could be linked to its phagocytosis resistance, nor to the intracellular survival observed for the 700603 strain. Our results indicate that both zebrafish and D. discoideum are advantageous host models to study different traits of K. pneumoniae that are associated with virulence.

The role of microglial activation in choroidal neovascular membranes of age-related macular degeneration patients

Objective To investigate the role of microglial activation in choroidal neovascular membranes(CNM) of age-related macular degeneration (AMD) patients. Methods Paraffin-embedded sections of CNM excised from 11 patients with wet AMD were collected. The microglial of sections were analyzed by immunohistochemistry with antibodies against HLA-DR antigen, CD 45 or CD 68. CNM were also dual labeled with CD 68 and vascular endothelium growth factor (VEGF). Results In inflammatory active CNM, abundant microglial cells were appeared characteristically amoeboid, with hypertrophic cell body and shorter process. In inflammatory inactive CNM, most of positive labeled microglial cells showed ramified, with small cell body and numerous nodular and slender processes. Double labeling study demonstrated that VEGF was mainly expressed in microglial cells. Conclusion Microglial are involved at different stages of the disease. Microglial activation is a prominent feature of the disease process. Key words: Neovascular, choroidal; Microglial; CD 68; CD 45; HLA-DR

Comparative examination on selected amphizoic amoebae in terms of their in vitro temperature tolerance – a possible indirect marker of potential pathogenicity of Acanthamoeba strains

Acanthamoeba species are ubiquitous in natural and man-made environments worldwide; some strains are able to colonize human eyes as facultative parasites. It has been shown that environmental and clinical isolates/species of Acanthamoeba vary in their pathogenicity. In this study we examine and compare the in vitro effects of the changing temperature on the population dynamics of subsequent amoebic strains. Identification of Acanthamoeba strain by morphological and molecular methods and temperature assays were performed. Monitoring of the corneal and environmental strains showed changes in population densities and a termo-tolerance correlating with pathogenicity of amoebae. Comparative assessment of results indicated differences in viability of amoebic populations in exponential growth phase in vitro cultivation. The increased awareness of the threat is needed for better understanding of impact of factors examined on pathogenesis in human infected with Acanthamoeba strains.

The mature and immature spermatozoa of the free-living marine nematode Daptonema sp. (Nematoda: Monhysterida: Xyalidae)

The immature spermatozoa stored in the testis and female postvulval uterine sac (PUS), and mature spermatozoa from the uterus of the free-living marine nematode Daptonema sp. (Monhysterida: Monhysterina: Xyalidae) were studied. The spermatozoa have a nucleus without a nuclear envelope. The central cytoplasm of the immature spermatozoa from the testis and the distal part of the PUS is occupied by a mass of pale fibrous bodies (FB) surrounded by mitochondria and osmiophilic membranous organelles (MO). The spermatozoa in the proximal half of PUS have a wide peripheral layer of electron lucent filamentous cytoplasm. The uterus lumen contains an aggregation of mature spermatozoa of which the periphery is transformed into pseudopods. The FB replaced by a voluminous electron-lucent halo bounded by a continuous layer of MO, mitochondria and fibrous matter. The MO may be intact, but numerous MO are fused with the plasma membrane, having been transformed into transparent pouches, each one opening to the exterior via a pore. Ultrastructural data showed that the activation is regulated in the female when spermatozoa migrate toward the uterus and transform into amoeboid mature spermatozoa. In general, the spermatozoa of Daptonema sp. and some other Monhysterina closely resemble those of the taxa belonging to the order Rhabditida. However, the `rhabditid' pattern of spermatozoon structure and development is most likely the plesiomorphic state in Rhabditida and close sister groups.

Non-Gaussianity, population heterogeneity, and transient superdiffusion in the spreading dynamics of amoeboid cells.

What is the underlying diffusion process governing the spreading dynamics and search strategies employed by amoeboid cells? Based on the statistical analysis of experimental single-cell tracking data of the two-dimensional motion of the Dictyostelium discoideum amoeboid cells, we quantify their diffusive behaviour based on a number of standard and complementary statistical indicators. We compute the ensemble- and time-averaged mean-squared displacements (MSDs) of the diffusing amoebae cells and observe a pronounced spread of short-time diffusion coefficients and anomalous MSD-scaling exponents for individual cells. The distribution functions of the cell displacements, the long-tailed distribution of instantaneous speeds, and the velocity autocorrelations are also computed. In particular, we observe a systematic superdiffusive short-time behaviour for the ensemble- and time-averaged MSDs of the amoeboid cells. Also, a clear anti-correlation of scaling exponents and generalised diffusivity values for different cells is detected. Most significantly, we demonstrate that the distribution function of the cell displacements has a strongly non-Gaussian shape and-using a rescaled spatio-temporal variable-the cell-displacement data collapse onto a universal master curve. The current analysis of single-cell motions can be implemented for quantifying diffusive behaviours in other living-matter systems, in particular, when effects of active transport, non-Gaussian displacements, and heterogeneity of the population are involved in the dynamics.

Microglial dynamics during brain development.

Microglial dynamics during brain development.

A computational model of amoeboid cell motility in the presence of obstacles.

Locomotion of amoeboid cells is mediated by finger-like protrusions of the cell body, known as pseudopods, which grow, bifurcate, and retract in a dynamic fashion. Pseudopods are the primary mode of locomotion for many cells within the human body, such as leukocytes, embryonic cells, and metastatic cancer cells. Amoeboid motility is a complex and multiscale process, which involves bio-molecular reactions, cell deformation, and cytoplasmic and extracellular fluid motion. Additionally, cells within the human body are subject to a confined 3D environment known as the extra-cellular matrix (ECM), which resembles a fluid-filled porous medium. In this article, we present a 3D, multiphysics computational approach coupling fluid mechanics, solid mechanics, and a pattern formation model to simulate locomotion of amoeboid cells through a porous matrix composed of a viscous fluid and an array of finite-sized spherical obstacles. The model combines reaction-diffusion of activator/inhibitors, extreme deformation of the cell, pseudopod dynamics, cytoplasmic and extracellular fluid motion, and fully resolved extracellular matrix. A surface finite-element method is used to obtain the cell deformation and activator/inhibitor concentrations, while the fluid motion is solved using a combined finite-volume and spectral method. The immersed-boundary methods are used to couple the cell deformation, obstacles, and fluid. The model is able to recreate squeezing and weaving motion of cells through the matrix. We study the influence of matrix porosity, obstacle size, and cell deformability on the motility behavior. It is found that below certain values of these parameters, cell motion is completely inhibited. Phase diagrams are presented depicting such motility limits. Interesting dynamics seen in the presence of obstacles but absent in unconfined medium, such as freezing or cell arrest, probing, doubling-back, and tug-of-war are predicted. Furthermore, persistent unidirectional motion of cells that is often observed in an unconfined medium is shown to be lost in presence of obstacles, and is attributed to an alteration of the pseudopod dynamics. The same mechanism, however, allows the cell to find a new direction to penetrate further into the matrix without being stuck in one place. The results and analysis presented here show a strong coupling between cell deformability and ECM properties, and provide new fluid mechanical insights on amoeboid motility in confined medium.

Analysis of Random Migration of Dictyostelium Amoeba in Confined and Unconfined Environments.

Dictyostelium discoideum has proven to be an excellent model to study amoeboid cell migration. During their life cycle, Dictyostelium cells exhibit distinct modes of motility. Individual growth-phase cells explore new territories by random cell migration using the core cell motility machinery, but they can also hunt bacteria by detection and chemotaxis toward the by-product folate. After depletion of nutrients, the cells initiate a developmental program allowing streaming of the cells into aggregation centers by chemotaxis toward cAMP and by cell-to-cell adhesion. Subsequent development is associated with complex rotational movement of the compacted aggregates to drive cell type specific sorting, which in turn is necessary for terminal culmination and formation of fruiting bodies. Here we describe a protocol for the analyses of cell motility of vegetative Dictyostelium cells in unconfined and mechanically confined settings.

Survey on medicinal plants traditionally used in Senegal for the treatment of tuberculosis (TB) and assessment of their antimycobacterial activity

Ethnopharmacological relevanceIn West Africa, populations are used to taking traditional medicine as a first aid against common health problems. In this aspect, many plants are claimed to be effective in the treatment of Tuberculosis (TB), which according to the World Health Organization (WHO) remains one of the world’s deadliest communicable diseases. Aim of the studyThe main aim of this study was to identify plants used to treat TB-symptoms by the population of Senegal and to evaluate their possible concomitant use with clinically approved TB-drugs. This approach allowed the selection of plants effectively used in traditional medicine. In order to verify if the usage of some of these plants can be rationalized, the activity of their traditional preparations was assessed with both an intracellular and extracellular antimycobacterial host-pathogen assays. Materials and methodsAn ethnopharmacological survey conducted on 117 TB-patients and 30 healers in Senegal from March to May 2014. The questionnaires were focused on the use of medicinal plants to treat common TB -symptoms (cough longer than 2 weeks, fever, night sweats, weight loss and bloody sputum). Local plant names, utilized organs (herbal drugs) and traditional formulations of the plants were recorded. Extracts were prepared by mimicking the traditional decoction in boiling water and screened for their antimycobacterial activity using Mycobacterium marinum, as a validated TB surrogate, and an Acanthamoeba castellanii - M. marinum whole-cell based host-pathogen assay, to detect anti-infective activities. ResultsBy the end of the survey, nearly 30 plants were cited and the 12 most cited herbal drugs were collected and their usage documented by extensive literature search. Extracts of the chosen herbs were screened with the described assays; with a main focus on traditional formulas (mainly herbal decoctions). Two of the water extracts from Combretum aculeatum and Guiera senegalensis showed significant antimycobacterial activities when compared to the positive control drug (rifampin). These extracts showed no observable toxicity against amoeba host cells (Acanthamoeba castellanii). ConclusionsThis study demonstrates that most of the patients do not concomitantly use plants and TB drugs (~90% of informants) but, instead, most are treated with medicinal plants before they are admitted to a hospital (41%). Interestingly, among the aqueous extracts assayed, two extracts (Combretum aculeatum (Combretaceae) and Guiera senegalensis (Combretaceae)) collected within this survey demonstrate antimycobacterial activities on the validated whole-cell based host-pathogen assay. Both extracts showed significant activities against intracellular and extracellular - M. marinum growth presenting IC50 lower than 0.5mg/ml compared to the reference drug Rifampin (IC50 of 0.4 and 7µg/ml). No toxicity was observed for amoebae cells at concentration until 0.8mg/ml.