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Microbiology Spectrum Aug 2023The diatom Phaeodactylum tricornutum is regarded as a prospective "cell factory" for the high-value products fucoxanthin and eicosapentaenoic acid (EPA). However,...
The diatom Phaeodactylum tricornutum is regarded as a prospective "cell factory" for the high-value products fucoxanthin and eicosapentaenoic acid (EPA). However, contamination with grazing protozoa is a significant barrier to its commercial cultivation. Here, we describe a new species of heterolobosean amoeba, Euplaesiobystra perlucida, which caused the loss of in pilot-scale cultures. Morphological and molecular characteristics distinguish from the other species in the genus . is 1.4 to 3.2 times larger than other species in terms of average length/width and maximum length/width of the trophozoites. Unlike Euplaesiobystra salpumilio, has no cytostome; lacks a flagellate stage, whereas Euplaesiobystra hypersalinica and both display a flagellate stage in their life cycle. The small-subunit rRNA gene sequence of shared only 88.02% homology with that of its closest relative, Euplaesiobystra dzianiensis, and had two distinctive regions. Its phylogenetic branch was clustered with one uncultured heterolobosean clone (bootstrap support/posterior probability = 100%/1.00). Results of feeding experiments demonstrated that could graze on various unicellular and filamentous eukaryotic microalgae (chlorophytes, chrysophytes, euglenids, and diatoms) and cyanobacteria. 's ingestion rate declined exponentially with increasing size of unicellular prey, and attained the highest growth rates on . On the basis of its strong ability to graze on microalgae, capacity to form large populations in a short period of time, and capacity to form resistant resting cysts, this contaminant has the potential to cause severe problems in large-scale microalgal culture and merits further attention. Heteroloboseans have garnered considerable interest because of their extraordinary ecological, morphological, and physiological diversity. Many heteroloboseans have adapted to various extensive habitats, including halophilic, acidophilic, thermophilic, psychrophilic, and anaerobic habitats. Most heteroloboseans are bacterivores, with a few algivorous species reported. In this study, a new species of algivorous heterolobosean amoeba, , is described as a significant grazer that causes losses in outdoor industrial cultures. This study provides phenotypic, feeding, and genetic information on a previously unknown heterolobosean, emphasizes the impact of contaminating amoebae in commercial microalgal cultures, and will contribute to the management strategies for predicting this kind of contaminant in large-scale microalgal cultivation.
Topics: Amoeba; Diatoms; Phylogeny; Prospective Studies; Eukaryota
PubMed: 37378530
DOI: 10.1128/spectrum.00817-23 -
Parasites, Hosts and Diseases May 2024Naegleria fowleri invades the brain and causes a fatal primary amoebic meningoencephalitis (PAM). Despite its high mortality rate of approximately 97%, an effective...
Naegleria fowleri invades the brain and causes a fatal primary amoebic meningoencephalitis (PAM). Despite its high mortality rate of approximately 97%, an effective therapeutic drug for PAM has not been developed. Approaches with miltefosine, amphotericin B, and other antimicrobials have been clinically attempted to treat PAM, but their therapeutic efficacy remains unclear. The development of an effective and safe therapeutic drug for PAM is urgently needed. In this study, we investigated the anti-amoebic activity of Pinus densiflora leaf extract (PLE) against N. fowleri. PLE induced significant morphological changes in N. fowleri trophozoites, resulting in the death of the amoeba. The IC50 of PLE on N. fowleri was 62.3±0.95 μg/ml. Alternatively, PLE did not significantly affect the viability of the rat glial cell line C6. Transcriptome analysis revealed differentially expressed genes (DEGs) between PLE-treated and non-treated amoebae. A total of 5,846 DEGs were identified, of which 2,189 were upregulated, and 3,657 were downregulated in the PLE-treated amoebae. The DEGs were categorized into biological process (1,742 genes), cellular component (1,237 genes), and molecular function (846 genes) based on the gene ontology analysis, indicating that PLE may have dramatically altered the biological and cellular functions of the amoeba and contributed to their death. These results suggest that PLE has anti-N. fowleri activity and may be considered as a potential candidate for the development of therapeutic drugs for PAM. It may also be used as a supplement compound to enhance the therapeutic efficacy of drugs currently used to treat PAM.
Topics: Naegleria fowleri; Plant Extracts; Pinus; Plant Leaves; Animals; Rats; Antiprotozoal Agents; Cell Line; Trophozoites; Brain; Gene Expression Profiling; Central Nervous System Protozoal Infections; Inhibitory Concentration 50; Cell Survival
PubMed: 38835258
DOI: 10.3347/PHD.23103 -
Synthesis, anti-amoebic activity and molecular docking simulation of eugenol derivatives against sp.Saudi Pharmaceutical Journal : SPJ :... Sep 2023Amoebae of the genus can cause diseases such as amoebic keratitis and granulomatous amoebic encephalitis. Until now, treatment options for these diseases have not been...
Amoebae of the genus can cause diseases such as amoebic keratitis and granulomatous amoebic encephalitis. Until now, treatment options for these diseases have not been fully effective and have several drawbacks. Therefore, research into new drugs is needed for more effective treatment of infections. Eugenol, a phenolic aromatic compound mainly derived from cloves, has a variety of pharmaceutical properties. In this study, nine eugenol derivatives (K1-K9), consisting of five new and four known compounds, were synthesized and screened for their antiamoebic properties against sp. The structure of these compounds was characterized spectroscopically by Fourier transform infrared (FTIR), Ultraviolet-Visible (UV-Vis), H and C Nuclear Magnetic Resonance (NMR) and mass spectrometer (MS). The derived molecules were screened for antiamoebic activity by determining IC values based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and observation of amoeba morphological changes by light and fluorescence microscopy. Most of the tested compounds possessed strong to moderate cytotoxic effects against trophozoite cells with IC values ranging from 0.61 to 24.83 μg/mL. Observation of amoebae morphology by light microscopy showed that the compounds caused the transformed cells to be roundish and reduced in size. Furthermore, fluorescence microscopy observation using acridine orange (AO) and propidium iodide (PI) (AO/PI) staining showed that the cells have damaged membranes by displaying a green cytoplasm with orange-stained lysosomes. Acidification of the lysosomal structure indicated disruption of the internal structure of cells when treated with eugenol derivatives. The observed biological results were also confirmed by interaction simulations based on molecular docking between eugenol derivatives and profilin. These interactions could affect the actin-binding ability of the protein, disrupting the shape and mobility of The overall results of this study demonstrate that eugenol derivatives can be considered as potential drugs against infections caused by
PubMed: 37546528
DOI: 10.1016/j.jsps.2023.101703 -
Frontiers in Microbiology 2023[This corrects the article DOI: 10.3389/fmicb.2023.1149145.].
[This corrects the article DOI: 10.3389/fmicb.2023.1149145.].
PubMed: 37954236
DOI: 10.3389/fmicb.2023.1304196 -
BioRxiv : the Preprint Server For... Sep 2023Studies in the model systems, amoebae and HL-60 neutrophils, have shown that local Ras activity directly regulates cell motility or polarity. Localized Ras activation...
Studies in the model systems, amoebae and HL-60 neutrophils, have shown that local Ras activity directly regulates cell motility or polarity. Localized Ras activation on the membrane is spatiotemporally regulated by its activators, RasGEFs, and inhibitors, RasGAPs, which might be expected to create a stable 'front' and 'back', respectively, in migrating cells. Focusing on C2GAPB in amoebae and RASAL3 in neutrophils, we investigated how Ras activity along the cortex controls polarity. Since existing gene knockout and overexpression studies can be circumvented, we chose optogenetic approaches to assess the immediate, local effects of these Ras regulators on the cell cortex. In both cellular systems, optically targeting the respective RasGAPs to the cell front extinguished existing protrusions and changed the direction of migration, as might be expected. However, when the expression of C2GAPB was induced globally, amoebae polarized within hours. Furthermore, within minutes of globally recruiting either C2GAPB in amoebae or RASAL3 in neutrophils, each cell type polarized and moved more rapidly. Targeting the RasGAPs to the cell backs exaggerated these effects on migration and polarity. Overall, in both cell types, RasGAP-mediated polarization was brought about by increased actomyosin contractility at the back and sustained, localized F-actin polymerization at the front. These experimental results were accurately captured by computational simulations in which Ras levels control front and back feedback loops. The discovery that context-dependent Ras activity on the cell cortex has counterintuitive, unanticipated effects on cell polarity can have important implications for future drug-design strategies targeting oncogenic Ras.
PubMed: 37693515
DOI: 10.1101/2023.08.30.555648 -
Heliyon Mar 2024amoebic encephalitis (BAE) is a rare and severe parasitic infection of the central nervous system. Its delayed diagnosis and treatment are often due to the lack of...
amoebic encephalitis (BAE) is a rare and severe parasitic infection of the central nervous system. Its delayed diagnosis and treatment are often due to the lack of specific clinical manifestations and its poor prognosis. Reported mortality rates reach around 95%. The Balamuthia mandrillaris is also known as the "brain-eating amoeba." Recently, the use of metagenomic next-generation sequencing (mNGS) in clinical settings has led to an increase in BAE diagnoses. A case report detailing the use of mNGS to diagnose granulomatous encephalitis caused by the Baramsi amoeba has improved clinicians' understanding of this disease and helped reduce misdiagnoses and missed diagnoses.
PubMed: 38434374
DOI: 10.1016/j.heliyon.2024.e26905 -
Pathogens (Basel, Switzerland) Nov 2023Few studies have been conducted in the cooling systems of power plants; they have focused on , leaving a gap in the knowledge of other pathogenic free-living amoebae in...
Few studies have been conducted in the cooling systems of power plants; they have focused on , leaving a gap in the knowledge of other pathogenic free-living amoebae in this environment. The objective of this study was to determine the occurrence of saline-tolerant pathogenic in a geothermal power plant. The identification of isolated amoebae at genus level was carried out, observing their morphological characteristics; the determination of genotype and species of was performed via molecular biology (PCR). Water temperature ranged from 18 to 43 °C and conductivity from 4.0 × 10 to 8.7 × 10 μS/cm; this last value was greater than the seawater value. Only five amoeba genera were found. was in all the sampling sites, showing high saline tolerance. The high temperature, but mainly high conductivity, were the environmental conditions that determined the presence of pathogenic free-living amoebae in the hot water. All the strains of killed the mice, having a mortality of 40 to 100%. genotypes T10 and T5 were identified, T10 is rarely isolated from the environment, while T5 is more frequent. This is the first time that genotypes T5 and T10 have been reported in the environment in Mexico.
PubMed: 38003827
DOI: 10.3390/pathogens12111363 -
ACS Infectious Diseases Jun 2024Primary amoebic meningoencephalitis (PAM) is a rare and fulminant neurodegenerative disease caused by the free-living amoeba . Currently, there is a lack of standardized...
Primary amoebic meningoencephalitis (PAM) is a rare and fulminant neurodegenerative disease caused by the free-living amoeba . Currently, there is a lack of standardized protocols for therapeutic action. In response to the critical need for effective therapeutic agents, we explored the Global Health Priority Box, a collection of 240 compounds provided by the Medicines for Malaria Venture (MMV). From this pool, flucofuron emerged as a promising candidate, exhibiting high efficacy against trophozoites of both strains (ATCC 30808 IC : 2.58 ± 0.64 μM and ATCC 30215 IC: 2.47 ± 0.38 μM), being even active against the resistant cyst stage (IC: 0.88 ± 0.07 μM). Moreover, flucofuron induced diverse metabolic events that suggest the triggering of apoptotic cell death. This study highlights the potential of repurposing medications for treating challenging diseases, such as PAM.
Topics: Naegleria fowleri; Humans; Trophozoites; Antiprotozoal Agents; Drug Repositioning; Apoptosis; Central Nervous System Protozoal Infections; Amebiasis
PubMed: 38757533
DOI: 10.1021/acsinfecdis.4c00062 -
European Journal of Cell Biology Dec 2023Major facilitator superfamily domain-containing protein 8 (MFSD8) is a transmembrane protein that has been reported to function as a lysosomal chloride channel. In...
Major facilitator superfamily domain-containing protein 8 (MFSD8) is a transmembrane protein that has been reported to function as a lysosomal chloride channel. In humans, homozygous mutations in MFSD8 cause a late-infantile form of neuronal ceroid lipofuscinosis (NCL) called CLN7 disease. In the social amoeba Dictyostelium discoideum, Mfsd8 localizes to cytoplasmic puncta and vesicles, and regulates conserved processes during the organism's life cycle. Here, we used D. discoideum to examine the effect of mfsd8-deficiency on the secretome during the early stages of multicellular development. Mass spectrometry revealed 61 proteins that were differentially released by cells after 4 and 8 h of starvation. Most proteins were present in increased amounts in mfsd8 conditioned buffer compared to WT indicating that loss of mfsd8 deregulates protein secretion and/or causes the release of proteins not normally secreted by WT cells. GO term enrichment analyses showed that many of the proteins aberrantly released by mfsd8 cells localize to compartments and regions of the cell associated with the endo-lysosomal and secretory pathways. Mass spectrometry also revealed proteins previously known to be impacted by the loss of mfsd8 (e.g., cathepsin D), as well as proteins that may underlie mfsd8-deficiency phenotypes during aggregation. Finally, we show that mfsd8-deficiency reduces intracellular proteasome 20S activity due to the abnormal release of at least one proteasomal subunit. Together, this study reveals the impact of mfsd8 loss on the secretome during D. discoideum aggregation and lays the foundation for follow up work that investigates the role of altered protein release in CLN7 disease.
Topics: Humans; Dictyostelium; Secretome; Membrane Proteins; Mutation; Lysosomes; Membrane Transport Proteins
PubMed: 37742391
DOI: 10.1016/j.ejcb.2023.151361 -
Biomolecules Feb 2024Sterol biosynthesis via the mevalonate-isoprenoid pathway produces ergosterol (24β-methyl cholesta-5,7-dienol) necessary for growth in a wide-range of eukaryotic... (Review)
Review
Sterol biosynthesis via the mevalonate-isoprenoid pathway produces ergosterol (24β-methyl cholesta-5,7-dienol) necessary for growth in a wide-range of eukaryotic pathogenic organisms in eukaryotes, including the fungi, trypanosomes and amoebae, while their animal hosts synthesize a structurally less complicated product-cholesterol (cholest-5-enol). Because phyla-specific differences in sterol metabolizing enzyme architecture governs the binding and reaction properties of substrates and inhibitors while the order of sterol metabolizing enzymes involved in steroidogenesis determine the positioning of crucial chokepoint enzymes in the biosynthetic pathway, the selectivity and effectiveness of rationally designed ergosterol biosynthesis inhibitors toward ergosterol-dependent infectious diseases varies greatly. Recent research has revealed an evolving toolbox of mechanistically distinct tight-binding inhibitors against two crucial methylation-demethylation biocatalysts-the C24 sterol methyl transferase (absent from humans) and the C14-sterol demethylase (present generally in humans and their eukaryotic pathogens). Importantly for rational drug design and development, the activities of these enzymes can be selectively blocked in ergosterol biosynthesis causing loss of ergosterol and cell killing without harm to the host organism. Here, we examine recent advances in our understanding of sterol biosynthesis and the reaction differences in catalysis for sterol methylation-demethylation enzymes across kingdoms. In addition, the novelties and nuances of structure-guided or mechanism-based approaches based on crystallographic mappings and substrate specificities of the relevant enzyme are contrasted to conventional phenotypic screening of small molecules as an approach to develop new and more effective pharmacological leads.
Topics: Humans; Animals; Sterols; Cholesterol; Ergosterol; Methylation; Communicable Diseases
PubMed: 38540670
DOI: 10.3390/biom14030249