Single-celled Parasites Research Articles

Examination of the Toxicity Pattern and Influence of Azadirachta indica on Testicular Function and Expression of Proliferating Cell Nuclear Antigen in Plasmodium berghei-Infected Mice

Background: Malaria, a parasitic disease caused by a single-celled parasite called Plasmodium, poses a significant global health burden, especially in tropical regions such as Africa. The impact of malaria on human health is well-documented; however, its effects on the male reproductive system and the impact of herbal extracts remain underexplored. Objectives: This study aims to investigate Azadirachta indica's toxicity and its antimalarial potency's influence on testicular function and expression of proliferating cells nuclear antigen (PCNA). Methods: The antimalarial activity of Azadirachta indica was determined using standard procedures. Thirty male mice were used and grouped into six. Group 1 (normal control), group 2 (P. berghei infected only - negative control), group 3 (Plasmodium berghei infected + lonart - standard drug), group 4 (P. berghei infected + 100 mg/kg BWT crude ethanol extract), group 5 (P. berghei infected + 200 mg/kg BWT crude ethanol extract), group 6 (P. berghei infected + 400 mg/kg BWT crude ethanol extract). Administration of A. indica leaf extract to infected mice for four consecutive days demonstrated promising results. Results: The extract significantly suppressed parasite multiplication, ameliorated testicular damage, and improved sperm quality. The non-toxic extract also reduced oxidative stress in the testes, suggesting its potential effectiveness as phytotherapy against malaria-induced male reproductive impairments. Conclusions: The beneficial effects of A. indica emphasize its potential as a natural remedy for malaria-induced reproductive complications, offering a new avenue for therapeutic intervention in malaria-endemic regions. This study contributes to our knowledge of the intricate relationship between malaria and male reproductive health and provides valuable insights for future research and clinical applications.

Nanoscale Surface Metal-Coating Method without Pretreatment for High-Magnification Biological Observation and Applications.

Biospecimen imaging is essential across various fields. In particular, a considerable amount of research has focused on developing pretreatment techniques, ranging from freeze-drying to the use of highly conductive polymers, and on advancements in instrumentation, such as cryogenic electron microscopy. These specialized techniques and equipment have facilitated nanoscale and microscale bioimaging. However, user access to these environments remains limited. This study introduced a novel technique to achieve high conductivity in bioimaging by employing a magnetically controlled sputtering cathode to facilitate low-temperature deposition and low-electron bombardment. This approach allows for the convenient high-magnification observation of highly structured three-dimensional specimens, such as pill bugs and butterfly wings, and fragile specimens, such as single-cell protozoan parasites, using metal deposition only. Furthermore, it is easily accessible in the field of bioimaging because it does not require any pretreatment and enables surface analysis of biospecimens with an electron microscope using only a single pretreatment process. Protozoa, which are microorganisms, were successfully observed at high magnification without structural changes due to thermal denaturation. Furthermore, metallic film deposition and electrochemical signal measurements using these metallic films were achieved in pill bugs.

Mono-allelic epigenetic regulation of bi-directional silencing of RNA Polymerase II polycistronic transcription initiation in Trypanosoma brucei.

The single-cell parasite Trypanosoma brucei causes lethal diseases in both humans and livestock. T. brucei undergoes multiple developmental changes to adapt in different environments during its digenetic life cycle. With protein-coding genes organized as polycistronic transcription and apparent absence of promoter-mediated regulation of transcription initiation, it is believed that developmental gene regulation in trypanosomes is essentially post-transcriptional. In this study, we found reversible Pol II transcriptional silencing of two adjacent polycistronic gene arrays that correlates with the novel DNA base J modification of the shared promoter region. Our findings support epigenetic regulation of Pol II transcription initiation as a viable mechanism of gene expression control in T. brucei . This has implications for our understanding how trypanosomes utilize polycistronic genome organization to regulate gene expression during its life cycle.

On the host specificity and genetic diversity of Iodamoeba bütschlii: Observations from short amplicon-based next-generation sequencing

Iodamoeba is a single-celled intestinal parasite, which is common in humans in certain parts of the world, and also in pigs. For the first time, we provide DNA-based evidence of goat, dromedary, fallow deer, and donkey as hosts of Iodamoeba and show that Iodamoeba-specific nucleotide sequences from these four hosts do not appear to overlap with those of humans, unlike those from pigs. We moreover show that similar strains of Iodamoeba can be found in Madagascar, Western Sahara, and Ecuador and that intra-sample diversity is typically extensive across even small fragments of DNA in both human and non-human hosts.

Insights into trophic interactions: DNA metabarcoding reveals species composition in black-tailed gull fecal samples in coastal environments of South Korea.

This study explored the algae, zooplankton, macroinvertebrate, fish, and parasitic single-celled organism communities in Larus crassirostris (black-tailed gull) fecal samples from Baengnyeongdo, Hongdo, and Ulleungdo in South Korea. The fecal samples can identify key species consumed by black-tailed gull, providing insights into their, trophic interactions, and habitat dependencies. Using DNA metabarcoding, we identified algae, zooplankton, macroinvertebrate, fish, and intestinal and single-celled parasite species in the fecal samples. Parasitic single-celled organisms, such as Rhogostoma sp., Rhogostoma schuessleri, Eimeria furonis, and Aggregata eberthi, showed differing relative abundances at each sampling location, indicating variability in parasite diversity in the fecal DNA analysis of birds at each site. Intestinal parasites showed similar site-specific variability, though Clistobothrium sp. and Tetrabothrius sp. were common at all locations. Algae species, including Heterocapsa steinii, Heterocapsa niei, and Sargassum cristaefolium, also displayed habitat-specific patterns, as did zooplankton, with Calanus sp., Corycaeus speciosus, and Caprella californica being dominant on Baengnyeongdo, Hongdo, and Ulleungdo, respectively. In the macroinvertebrate communities, Octopus sinensis was prevalent at all locations but at varying abundances. Site-specific dominant fish species were also identified, with Ammodytes personatus, Decapterus maruadsi, and Arctoscopus japonicus highly predominant on Baengnyeongdo, Hongdo, and Ulleungdo, respectively. Other fish species, such as Ammodytes hexapterus, were detected in lower frequencies, suggesting a diverse diet for the seabirds. These results offer insights into the species composition and ecological dynamics in black-tailed gull populations across disparate Korean islands.

Selective host autophagy is induced during the intracellular parasite Toxoplasma gondii infection controlling amino acid levels.

Intracellular parasites employ several mechanisms to manipulate the cellular environment, enabling them to persist in the host. Toxoplasma gondii, a single-celled parasite, possesses the ability to infect virtually any nucleated cell of warm-blooded vertebrates, including nearly 2 billion people worldwide. Unfortunately, existing treatments and immune responses are not entirely effective in eliminating the chronic persisting forms of the parasite. This study reveals that T. gondii induces the host's autophagic pathway to boost amino acid levels in infected cells. The depletion of amino acids, in turn, influences the persistence of the parasite's chronic forms. Significantly, our investigation establishes the crucial role of host endoplasmic reticulum (ER)-phagy in the parasite's persistence within the host during latent infection.

New insights into Microsporidia polar tube function and invasion mechanism.

Microsporidia comprise a large phylum of single-cell and obligate intracellular parasites that can infect a wide range of invertebrate and vertebrate hosts including humans. These fungal-related parasites are characterized by a highly reduced genome, a strong energy dependence on their host, but also by their unique invasion organelle known as the polar tube which is coiled within the resistant spore. Upon appropriate environmental stimulation, the long hollow polar tube (ranging from 50 to 500 μm in length) is extruded at ultra-fast speeds (300 μm/s) from the spore acting as a harpoon-like organelle to transport and deliver the infectious material or sporoplasm into the host cell. To date, seven polar tube proteins (PTPs) with distinct localizations along the extruded polar tube have been described. For example, the specific location of PTP4 and PTP7 at the tip of the polar tube supports their role in interacting with cellular receptor(s). This chapter provides a brief overview on the current understanding of polar tube structure and dynamics of extrusion, primarily through recent advancements in cryo-tomography and 3D reconstruction. It also explores the various mechanisms used for host cell invasion. Finally, recent studies on the structure and maturation of sporoplasm and its moving through the tube are discussed.

ScRNA-seq reveals transcriptional dynamics of Encephalitozoon intestinalis parasites in human macrophages.

Microsporidia are single-celled intracellular parasites that cause opportunistic diseases in humans. Encephalitozoon intestinalis is a prevalent human-infecting species that invades the small intestine. Dissemination to other organ systems is also observed, and is potentially facilitated by macrophages. The macrophage response to infection and the developmental trajectory of the parasite are not well studied. Here we use single cell RNA sequencing to investigate transcriptional changes in both the host and parasite during infection. While a small population of infected macrophages mount a response, most remain transcriptionally unchanged, suggesting that the majority of parasites may avoid host detection. The parasite transcriptome reveals large transcriptional changes throughout the life cycle, providing a blueprint for parasite development. The stealthy microsporidian lifestyle likely allows these parasites to harness macrophages for replication and dissemination. Together, our data provide insights into the host response in primary human macrophages and the E. intestinalis developmental program.

Harnessing the power of new genetic tools to illuminate Giardia biology and pathogenesis.

Giardia is a prevalent single-celled microaerophilic intestinal parasite causing diarrheal disease and significantly impacting global health. Double diploid (essentially tetraploid) Giardia trophozoites have presented a formidable challenge to the development of molecular genetic tools to interrogate gene function. High sequence divergence and the high percentage of hypothetical proteins lacking homology to proteins in other eukaryotes have limited our understanding of Giardia protein function, slowing drug target validation and development. For more than 25 years, Giardia A and B assemblages have been readily amenable to transfection with plasmids or linear DNA templates. Here, we highlight the utility and power of genetic approaches developed to assess protein function in Giardia, with particular emphasis on the more recent clustered regularly interspaced palindromic repeats/Cas9-based methods for knockdowns and knockouts. Robust and reliable molecular genetic approaches are fundamental toward the interrogation of Giardia protein function and evaluation of druggable targets. New genetic approaches tailored for the double diploid Giardia are imperative for understanding Giardia's unique biology and pathogenesis.

Molecular detection and genotyping of Dientamoeba fragilis and Blastocystis sp. in housefly Musca domestica (Diptera: Muscidae): first report for Dientamoeba fragilis.

Dientamoeba fragilis and Blastocystis sp. are single-celled protozoan parasites of humans and animals. Although they are found in the intestines of healthy hosts, the pathogenicity of them is still unclear. To date, there is no report on D. fragilis and only two studies (without subtyping) on the occurrence of Blastocystis sp. in Musca domestica. In this study, fly samples were collected from livestock farms and their surroundings in the Kirsehir province (Central Anatolia Region) of Türkiye from May to August 2023. A total of 150 microscopically identified M. domestica samples were analyzed for the detection of D. fragilis and Blastocystis sp. molecularly. The overall prevalence of Blastocystis sp. and D. fragilis in M. domestica was determined to be 3.3% (5/150) and 8.0% (12/150), respectively. The SSU rRNA gene sequences of the isolates indicated genotype 1 of D. fragilis. Eleven isolates were identical and represented a single isolate (KAU-Dfrag1). BLAST analysis of KAU-Dfrag1 indicated identity with the isolates reported from humans, cattle, sheep, and budgerigars. The other isolate (KAU-Dfrag2) was polymorphic at two nucleotides from KAU-Dfrag1 and three nucleotides from known genotypes from GenBank and represented a variant of genotype 1. The Blastocystis sp. isolates were found to be identical and represent a single genotype (KAU-Blast1). BLAST analysis revealed that the KAU-Blast1 genotype belonged to the potentially zoonotic subtype 5 (ST5) and exhibited the highest genetic identity (ranging from 99.4 to 99.6%) with pigs, cattle, and sheep from different countries. Our study provides the first data on the molecular prevalence, epidemiology, and genotypic characterization of D. fragilis and Blastocystis sp. in M. domestica.

Detection and Sequence Analysis of Toxoplasma Gondii B1 Gene in Tissues of Some Bird Species in Plateau State, Nigeria

Abstract Toxoplasma gondii is a single-cell parasite capable of infecting almost all homeotherms posing a grave public health risk globally. There is limited available literature on the T. gondii strains circulating in bird species in the Plateau State, of Nigeria. Consequently, this study was carried out to identify and confirm T. gondii infection and also determine the relationship of the DNA sequences with those of bird species in other parts of the world. To achieve this, brain and heart tissues of 25 bird species were sampled and a nested polymerase chain reaction (nPCR) and sequence analyses of the B1 gene were carried out. The DNA of T. gondii was identified in the heart and brain tissues of 7/7 (100.0 %) of wild bird species, and 15/18 (83.3 %) of domestic local chickens (Gallus gallus domesticus) sampled. The evolutionary relationship among the T. gondii sequences in this study using phylogenetic tree constructed by maximum likelihood method showed the sequences shared a common ancestor with the Type I RH strain (GenBank: AF179871). The T. gondii sequences were in a cluster distinct from other sequences in the GenBank. Calculations of genetic differentiation and genetic diversity indices undertaken and collated revealed three haplotypes with higher haplotype diversity within the T. gondii sequences obtained from wild birds (0.667) compared with the sequences from local chickens (0.333). A 97–100 % homology among the aligned sequences of T. gondii in the study shows that only one strain type exists in all of the samples. This study has established the occurrence of T. gondii infection in asymptomatic bird species in the study area and portrays them as carriers, and potential sources of human infection.

Advances in the Immunology of the Host-Parasite Interactions in African Trypanosomosis, including Single-Cell Transcriptomics.

Trypanosomes are single-celled extracellular parasites that infect mammals, including humans and livestock, causing global public health concerns and economic losses. These parasites cycle between insect vectors, such as tsetse flies and vertebrate hosts, undergoing morphological, cellular, and biochemical changes. They have remarkable immune evasion mechanisms to escape the host's innate and adaptive immune responses, such as surface coat antigenic variation and the induction of the loss of specificity and memory of antibody responses, enabling the prolongation of infection. Since trypanosomes circulate through the host body in blood and lymph fluid and invade various organs, understanding the interaction between trypanosomes and tissue niches is essential. Here, we present an up-to-date overview of host-parasite interactions and survival strategies for trypanosomes by introducing and discussing the latest studies investigating the transcriptomics of parasites according to life cycle stages, as well as host cells in various tissues and organs, using single-cell and spatial sequencing applications. In recent years, this information has improved our understanding of trypanosomosis by deciphering the diverse populations of parasites in the developmental process, as well as the highly heterogeneous immune and tissue-resident cells involved in anti-trypanosome responses. Ultimately, the goal of these approaches is to gain an in-depth understanding of parasite biology and host immunity, potentially leading to new vaccination and therapeutic strategies against trypanosomosis.

Production, characterization and therapeutic efficacy of egg yolk antibodies specific to Nosema ceranae.

Nosema disease, caused by Nosema ceranae, one of the single-celled fungal microsporidian parasites, is one of the most important and common diseases of adult honey bees. Since fumagillin, which has been used for decades in the control of Nosema disease in honey bees (Apis mellifera), poses a toxic threat and its efficacy against N. ceranae is uncertain, there is an urgent need to develop alternative prophylactic and curative strategies for the treatment of this disease. The main aim of this study was to investigate the therapeutic potential of specific egg yolk immunoglobulins (IgY) on Nosema disease. For this purpose, the presence of N. ceranae was determined by microscopic and PCR methods in honey bees collected from Nosema suspicious colonies by conducting a field survey. Layered Ataks chickens, divided into four groups each containing 20 animals, were vaccinated with live and inactivated vaccines prepared from field isolates of N. ceranae. Eggs were collected weekly for 10 weeks following the last vaccination. IgY extraction was performed using the PEG precipitation method from egg yolks collected from each group, and the purity of the antibodies was determined by SDS-PAGE and Western Blot. The presence of N. ceranae-specific IgYs was investigated by Western Blot and indirect ELISA methods. It was determined that specific IgYs showed high therapeutic efficacy on Nosema disease in naturally infected bee colonies. In addition, honey bees collected from infected colonies were brought to the laboratory and placed in cages with 30 bees each, and the effectiveness of IgYs was investigated under controlled conditions. It was detected that specific IgY reduced the Nosema spore load and the number of infected bees significantly in both the field and experimental study groups treated for seven days. It was concluded that chicken IgYs, an innovative and eco-friendly method, had a significant potential for use as an alternative to antifungal drugs.

Co-infection of toxoplasma and blastocystis sp. in a CKD patient with SLE background: A case report

Toxoplasma and Blastocystis sp. are two common single-celled parasites found worldwide. Although the pathogenesis of Blastocystis sp. is still unknown, it is frequently reported in immunocompromised patients. Toxoplasmosis is also becoming a primary health

Scoping Review of Deep Learning Techniques for Diagnosis, Drug Discovery, and Vaccine Development in Leishmaniasis

Leishmania, a single-cell parasite prevalent in tropical and subtropical regions worldwide, can cause varying degrees of leishmaniasis, ranging from self-limiting skin lesions to potentially fatal visceral complications. As such, the parasite has been the subject of much interest in the scientific community. In recent years, advances in diagnostic techniques such as flow cytometry, molecular biology, proteomics, and nanodiagnosis have contributed to progress in the diagnosis of this deadly disease. Additionally, the emergence of artificial intelligence (AI), including its subbranches such as machine learning and deep learning, has revolutionized the field of medicine. The high accuracy of AI and its potential to reduce human and laboratory errors make it an especially promising tool in diagnosis and treatment. Despite the promising potential of deep learning in the medical field, there has been no review study on the applications of this technology in the context of leishmaniasis. To address this gap, we provide a scoping review of deep learning methods in the diagnosis of the disease, drug discovery, and vaccine development. In conducting a thorough search of available literature, we analyzed articles in detail that used deep learning methods for various aspects of the disease, including diagnosis, drug discovery, vaccine development, and related proteins. Each study was individually analyzed, and the methodology and results were presented. As the first and only review study on this topic, this paper serves as a quick and comprehensive resource and guide for the future research in this field.

Investigation of the effects of Toxoplasma gondii on behavioral and molecular mechanism in bradyzoite stage

Toxoplasma gondii is a single-celled parasite that causes a disease called toxoplasmosis. It can reach the central nervous system, but the mechanism of T. gondii disrupting the functioning of these brain regions occurs in bradyzoite stage of parasite, causing brain damage by forming tissue cysts in brain. In our study, the effects of T. gondii on locomotor activity, anxiety, learning and memory, and norepinephrine (NE), levodopa (L-DOPA), dopamine (DA) and 3,4-D-dihydroxyphenylacetic acid (DOPAC) catecholamines in amygdala, striatum, prefrontal cortex and hippocampus regions of the brain were investigated in bradyzoite stage. Twenty male Albino mice Mus musculus, 4–5 weeks old, weighing 20–25 g, were used. T. gondii inoculated to mice intraperitonealy with 48–50-hour passages of T. gondii RH Ankara strain. For intraperitoneal inoculation of mice 5x104 tachyzoites per mouse. No inoculation was made in control group (n: 20). Locomotor activity behavior in open field test (OFT), anxious behavior in elevated plus maze (EPM), and learning behavior in novel object recognition (NOR) tests were evaluated. NE, L-DOPA, DA and DOPAC were measured by HPLC in brain tissues of amygdala, striatum, prefrontal cortex and hippocampus. A decrease was observed in the locomotor activity, anxiety and learning values of the T. gondii group compared to the control group (p < 0.05). The heighten in NE and L-DOPA levels in amygdala tissue of T. gondii group compared to control group, an elevation in NE, L-DOPA, DA and DOPAC levels in striatum tissue, and an increase in levels of NE in prefrontal cortex tissue were detected in monoamine results. In hippocampus tissue, an increase was observed in DA levels, while a decrease was observed in NE, L-DOPA and DOPAC levels. In our study, it has been shown that T. gondii in bradyzoite stage reduces locomotor activity, causes learning and memory impairment, and has anxiogenic effects.

Polyploidy is widespread in Microsporidia.

Microsporidia are obligate intracellular eukaryotic parasites with an extremely broad host range. They have both economic and public health importance. Ploidy in microsporidia is variable, with a few species formally identified as diploid and one as polyploid. Given the increase in the number of studies sequencing microsporidian genomes, it is now possible to assess ploidy levels across all currently explored microsporidian diversity. We estimate ploidy for all microsporidian data sets available on the Sequence Read Archive using k-mer-based analyses, indicating that polyploidy is widespread in Microsporidia and that ploidy change is dynamic in the group. Using genome-wide heterozygosity estimates, we also show that polyploid microsporidian genomes are relatively homozygous, and we discuss the implications of these findings on the timing of polyploidization events and their origin.IMPORTANCEMicrosporidia are single-celled intracellular parasites, distantly related to fungi, that can infect a broad range of hosts, from humans all the way to protozoans. Exploiting the wealth of microsporidian genomic data available, we use k-mer-based analyses to assess ploidy status across the group. Understanding a genome's ploidy is crucial in order to assemble it effectively and may also be relevant for better understanding a parasite's behavior and life cycle. We show that tetraploidy is present in at least six species in Microsporidia and that these polyploidization events are likely to have occurred independently. We discuss why these findings may be paradoxical, given that Microsporidia, like other intracellular parasites, have extremely small, reduced genomes.

Toxoplasma protein export and effector function.

Toxoplasma gondii is a single-celled eukaryotic parasite with a considerable host range that must invade the cells of warm-blooded hosts to survive and replicate. The challenges and opportunities that such a strategy represent have been met by the evolution of effectors that are delivered into host cells, counter host defences and co-opt host cell functions for their own purposes. These effectors are delivered in two waves using distinct machinery for each. In this Review, we focus on understanding the architecture of these protein-export systems and how their protein cargo is recognized and selected. We discuss the recent findings on the role that host manipulation has in latent Toxoplasma infections. We also discuss how these recent findings compare to protein export in the related Plasmodium spp. (the causative agent of malaria) and how this can inform our understanding of host manipulation in the larger Apicomplexa phylum and its evolution.

Single-celled parasites and epidemiological causes of the spread of Ambia disease in south Baghdad areas

Single-celled parasites and epidemiological causes of the spread of Ambia disease in south Baghdad areas

Evolutionary modelling indicates that mosquito metabolism shapes the life-history strategies of Plasmodium parasites

Within-host survival and between-host transmission are key life-history traits of single-celled malaria parasites. Understanding the evolutionary forces that shape these traits is crucial to predict malaria epidemiology, drug resistance, and virulence. However, very little is known about how Plasmodium parasites adapt to their mosquito vectors. Here, we examine the evolution of the time Plasmodium parasites require to develop within the vector (extrinsic incubation period) with an individual-based model of malaria transmission that includes mosquito metabolism. Specifically, we model the metabolic cascade of resource allocation induced by blood-feeding, as well as the influence of multiple blood meals on parasite development. Our model predicts that successful vector-to-human transmission events are rare, and are caused by long-lived mosquitoes. Importantly, our results show that the life-history strategies of malaria parasites depend on the mosquito’s metabolic status. In our model, additional resources provided by multiple blood meals lead to selection for parasites with slow or intermediate developmental time. These results challenge the current assumption that evolution favors fast developing parasites to maximize their chances to complete their within-mosquito life cycle. We propose that the long sporogonic cycle observed for Plasmodium is not a constraint but rather an adaptation to increase transmission potential.