BackgroundToxoplasma gondii is an obligate intracellular parasite that infects humans and other warm-blooded animals. Previous quantitative proteomic analyses of infected host cells revealed that the expression of many host proteins is modulated by T. gondii infection. However, at present limited data are available on the differentially expressed miRNAs (DEMs) associated with the pathology and host immune responses induced by acute and chronic infection with T. gondii in pigs in vivo. In this study, high-throughput sequencing was used to investigate expression profiles of spleen miRNAs at 10, 25 and 50 days post-infection (DPI) in pigs infected with Chinese I genotype strain T. gondii isolated from a dead pig.ResultsWhen compared to the control group, 34, 6 and 86 DEMs were found in spleens of infected pigs at 10, 25 and 50 DPI, respectively. Gene Ontology (GO) enrichment analysis of the target genes of DEMs showed that no GO terms were enriched at 25 DPI, whereas 28 and 241 GO terms, of which two and 215 were sample-specific, were significantly enriched at 10 and 50 DPI, respectively. The top 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the target genes of DEMs included signal transduction, immune system, metabolism and diseases. miRNA–gene network analysis revealed that the DEMs played important roles in the host immune response to T. gondii infection by modulating expression levels of cellular immunity-related cytokines and immune-related C-type lectins.ConclusionOur results not only showed that host miRNA expression is altered by T. gondii but also revealed differences in the regulation of key biological processes and pathways involved in host responses to acute versus chronic T. gondii infection. This will aid future research into miRNA-target interactions during T. gondii infection in pigs and the development of novel therapies against T. gondii.Electronic supplementary materialThe online version of this article (10.1186/s12864-019-5458-y) contains supplementary material, which is available to authorized users.

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Background Eimeria is a common genus of apicomplexan parasites that infect diverse vertebrates, most notably poultry, causing serious disease and economic losses. Eimeria species have complex life-cycles consisting of three developmental stages. However, the molecular basis of the Eimeria reproductive mode switch remains an enigma.MethodsTotal RNA extracted from second- (MZ-2) and third-generation merozoites (MZ-3) of Eimeria necatrix was subjected to transcriptome analysis using RNA sequencing (RNA-seq) followed by qRT-PCR validation.ResultsA total of 6977 and 6901 unigenes were obtained from MZ-2 and MZ-3, respectively. Approximately 2053 genes were differentially expressed genes (DEGs) between MZ-2 and MZ-3. Compared with MZ-2, 837 genes were upregulated and 1216 genes were downregulated in MZ-3. Approximately 95 genes in MZ-2 and 48 genes in MZ-3 were further identified to have stage-specific expression. Gene ontology category and KEGG analysis suggested that 216 upregulated genes in MZ-2 were annotated by 70 GO assignments, 242 upregulated genes were associated with 188 signal pathways, while 321 upregulated genes in MZ-3 were annotated by 56 GO assignments, 322 upregulated genes were associated with 168 signal pathways. The molecular functions of upregulated genes in MZ-2 were mainly enriched for protein degradation and amino acid metabolism. The molecular functions of upregulated genes in MZ-3 were mainly enriched for transcriptional activity, cell proliferation and cell differentiation.ConclusionsTo the best of our knowledge, this is the first RNA-seq data study of the MZ-2 and MZ-3 stages of E. necatrix; it demonstrates a high number of differentially expressed genes between the MZ-2 and MZ-3 of E. necatrix. This study forms a basis for deciphering the molecular mechanisms underlying the shift from the second to third generation schizogony in Eimeria. It also provides valuable resources for future studies on Eimeria, and provides insight into the understanding of reproductive mode plasticity in different Eimeria species.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2325-z) contains supplementary material, which is available to authorized users.

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Toxoplasma gondii is an obligate intracellular parasite with worldwide distribution. Virulence of T. gondii is a multigenic trait. Genetic and virulence data for T. gondii isolates from humans and animals in China have been reported. However, almost all biological materials used for genotyping of T. gondii from humans and pigs were DNA samples prepared from tissues, and T. gondii strains used for virulence analysis were isolated mainly from cats. In this study, one isolate from a dead human fetus was identified as type I (ToxoDB #10) while the two isolates from dead pigs were type Chinese I (ToxoDB #9) with PCR-restriction fragment length polymorphism using 10 markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). Three isolates were comfirmed as virulent strains in mice. By cloning and sequences analysis, all isolates contained a Pvu II restriction site (572-577 bp) in the KHB fragment and five tandem repeats in the 5' UTR region of SAG1, which were associated with T. gondii virulence. The type Chinese I isolates contained two deletions of 15 and 3 bp at positions 635 to 649 and 658 to 660 in the GRA6, which were correlated with genotype, but not with virulence. To our knowledge, this is the first report on the systematic analysis of murine virulence of type Chinese I strain from pigs, and the associations of sequences of the KHB fragment and SAG1 with virulence of type Chinese I strain. The Chinese I genotype was more closely related to type II strains.

Toxoplasmosis is a global zoonotic disease, and one-third of the human population is chronically infected by Toxoplasma gondii. Due to the limited effectiveness and prominent side effects of the existing drugs, there is a dire need for the discovery of new therapeutic options in the treatment of toxoplasmosis. In this study, five essential oils (EO) were screened for their anti-parasitic activity against T. gondii. The cytotoxicity of essential oils was evaluated using the MTT assay on human foreskin fibroblast cells. The CC50 values of Eucalyptus globulus EO, Cupressus sempervirens EO, Citrus aurantifolia EO, Melaleuca alternifolia EO, and Pelargonium X. asperum (Pa) EO were found to be 22.74, 7.25, 15.01, 6.26, and 4.77 mg/mL, respectively. Only PaEO exhibited anti-parasitic activity, and inhibited the growth of T. gondii in a dose-dependent manner. In addition, treatment with PaEO, was found to reduce the volume of T. gondii tachyzoites and make their membrane surfaces rough. These results showed that PaEO was able to inhibit the growth of T. gondii by reducing invasion, which may be due to its detrimental effect on the ability of tachyzoites to move. These findings suggest that PaEO could be a potential anti-T. gondii drug, which may facilitate the development of new and effective treatments against toxoplasmosis.

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Background Toxoplasma gondii is an obligate intracellular protozoan parasite that can cause a geographically widespread zoonosis. Our previous splenocyte microRNA profile analyses of pig infected with T. gondii revealed that the coordination of a large number of miRNAs regulates the host immune response during infection. However, the functions of other miRNAs involved in the immune regulation during T. gondii infection are not yet known. Methods Clustering analysis was performed by K-means, self-organizing map (SOM), and hierarchical clustering to obtain miRNA groups with the similar expression patterns. Then, the target genes of the miRNA group in each subcluster were further analyzed for functional enrichment by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway to recognize the key signaling molecules and the regulatory signatures of the innate and adaptive immune responses of the host during T. gondii infection. Results A total of 252 miRNAs were successfully divided into 22 subclusters by K-means clustering (designated as K1–K22), 29 subclusters by SOM clustering (designated as SOM1–SOM29), and six subclusters by hierarchical clustering (designated as H1–H6) based on their dynamic expression levels in the different infection stages. A total of 634, 660, and 477 GO terms, 15, 26, and 14 KEGG pathways, and 16, 15, and 7 Reactome pathways were significantly enriched by K-means, SOM, and hierarchical clustering, respectively. Of note, up to 22 miRNAs mainly showing downregulated expression at 50 days post-infection (dpi) were grouped into one subcluster (namely subcluster H3-K17-SOM1) through the three algorithms. Functional analysis revealed that a large group of immunomodulatory signaling molecules were controlled by the different miRNA groups to regulate multiple immune processes, for instance, IL-1-mediated cellular response and Th1/Th2 cell differentiation partly depending on Notch signaling transduction for subclusters K1 and K2, innate immune response involved in neutrophil degranulation and TLR4 cascade signaling for subcluster K15, B cell activation for subclusters SOM17, SOM1, and SOM25, leukocyte migration, and chemokine activity for subcluster SOM9, cytokine–cytokine receptor interaction for subcluster H2, and interleukin production, chemotaxis of immune cells, chemokine signaling pathway, and C-type lectin receptor signaling pathway for subcluster H3-K17-SOM1. Conclusions Cluster analysis of splenocyte microRNAs in the pig revealed key regulatory properties of subcluster miRNA molecules and important features in the immune regulation induced by acute and chronic T. gondii infection. These results contribute new insight into the identification of physiological immune responses and maintenance of tolerance in pig spleen tissues during T. gondii infection. Graphical Abstract