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Pesticide Biochemistry and Physiology May 2021Energy metabolism is important for the proliferation of microsporidia in infected host cells, but there is limited information on the host response. The energy...
Energy metabolism is important for the proliferation of microsporidia in infected host cells, but there is limited information on the host response. The energy metabolism response of silkworm (Bombyx mori) to microsporidia may help manage Nosema bombycis infections. We analyzed differentially expressed genes in the B.mori midgut transcriptome at two significant time points of microsporidia infection. A total of 1448 genes were up-regulated, while 315 genes were down-regulated. A high proportion of genes were involved in the phosphatidylinositol signaling system, protein processing in the endoplasmic reticulum, and glycerolipid metabolism at 48 h post infection (h p.i.), and a large number of genes were involved in the TCA cycle and protein processing at 120 h p.i. These results showed that the early stages of microsporidia infection affected the basic metabolism and biosynthesis processes of the silkworm. Knockout of Bm_nscaf2860_46 (Bombyx mori isocitrate dehydrogenase, BmIDH) and Bm_nscaf3027_062 (Bombyx mori hexokinase, BmHXK) reduced the production of ATP and inhibited microsporidia proliferation. Host fatty acid degradation, glycerol metabolism, glycolysis pathway, and TCA cycle response to microsporidia infection were also analyzed, and their importance to microsporidia proliferation was verified. These results increase our understanding of the molecular mechanisms involved in N. bombycis infection and provide new insights for research on microsporidia control. IMPORTANCE: Nosema bombycis can be vertically transmitted in silkworm eggs. The traditional prevention and control strategies for microsporidia are difficult and time-consuming, and this is a problem in silkworm culture. Research has mainly focused on host gene functions related to microsporidia infection and host immune responses after microsporidia infection. Little is known about the metabolic changes occurring in the host after infection. Understanding the metabolic changes in the silkworm host could aid in the recognition of host genes important for microsporidia infection and growth. We analyzed host metabolic changes and the main participating pathways at two time points after microsporidia infection and screened the microsporidia-dependent host energy metabolism genes BmIDH and BmHXK. The results revealed genes that are important for the proliferation of Nosema bombycis. These results illustrate how microsporidia hijack the host genome for their growth and reproduction.
Topics: Animals; Bombyx; Energy Metabolism; Gene Expression Profiling; Nosema
PubMed: 33838710
DOI: 10.1016/j.pestbp.2021.104809 -
Experientia Supplementum (2012) 2022Microsporidia are obligate intracellular pathogens that were initially identified about 160 years ago. Current phylogenetic analysis suggests that they are grouped with...
Microsporidia are obligate intracellular pathogens that were initially identified about 160 years ago. Current phylogenetic analysis suggests that they are grouped with Cryptomycota as a basal branch or sister group to the fungi. Microsporidia are found worldwide and can infect a wide range of animals from invertebrates to vertebrates, including humans. They are responsible for a variety of diseases once thought to be restricted to immunocompromised patients but also occur in immunocompetent individuals. The small oval spore containing a coiled polar filament, which is part of the extrusion and invasion apparatus that transfers the infective sporoplasm to a new host, is a defining characteristic of all microsporidia. When the spore becomes activated, the polar filament uncoils and undergoes a rapid transition into a hollow tube that will transport the sporoplasm into a new cell. The polar tube has the ability to increase its diameter from approximately 100 nm to over 600 nm to accommodate the passage of an intact sporoplasm and penetrate the plasmalemma of the new host cell. During this process, various polar tube proteins appear to be involved in polar tube attachment to host cell and can interact with host proteins. These various interactions act to promote host cell infection.
Topics: Animals; Cytoplasm; Humans; Microsporidia; Phylogeny; Spores, Fungal
PubMed: 35544004
DOI: 10.1007/978-3-030-93306-7_8 -
Indian Journal of Medical Microbiology 2020Microsporidium is a spore-forming intracellular parasite that affects a wide range of hosts including humans. The tumor necrosis factor alpha (TNF-α) plays a key role...
PURPOSE
Microsporidium is a spore-forming intracellular parasite that affects a wide range of hosts including humans. The tumor necrosis factor alpha (TNF-α) plays a key role in the immunity to infection with microsporidia. Recently, the TNF-α antagonists have proven successful in treating variable autoimmune diseases. In the current study, we aimed to investigate the impact of using TNF-α antagonists as a therapeutic regimen in the prevalence of infections with microsporidia.
MATERIALS AND METHODS
Diarrheal patients with distinct autoimmune diseases (n = 100) were assigned to the study. Patients taking anti-TNF-α medications (n = 60) were allocated to Group 1A and those undergoing non-TNF-α inhibitor treatment (n = 40) to Group 1B. Furthermore, patients with diarrhea without autoimmune disorders (n = 20) were allocated as controls. Stool specimens, 3 per patient, were collected and microscopically examined for microsporidia spores. A microsporidia-specific stool polymerase chain reaction was used to confirm the microscopic findings.
RESULTS
Microsporidia infection was identified in 28.3% (17/60), 10% (4/40), and in 5% (1/20) of patients in Group 1A, Group 1B, and in the control group, respectively. Overall, infection was significantly high in cases compared to the controls and in patients receiving TNF-α antagonists compared to patients not given TNF-α inhibitors (P < 0.05). Finally, infection was significantly higher in cases treated with TNF-α antagonists for ≥2 months compared to cases treated for <2 months of duration (P < 0.05).
CONCLUSION
There was a significant increase in microsporidia infection in autoimmune disease patients undergoing treatment with TNF-α antagonists, and the duration of treatment is one of the risk factors. The study highlights the importance of microsporidia testing in immunocompromised patients, particularly those undergoing treatment with anti-TNF-α drugs and emphasises the need for awareness among clinicians regarding this opportunistic parasite.
Topics: Autoimmune Diseases; Case-Control Studies; Diarrhea; Feces; Female; Humans; Male; Microsporidia; Microsporidiosis; Polymerase Chain Reaction; Prospective Studies; Tumor Necrosis Factor-alpha
PubMed: 33154255
DOI: 10.4103/ijmm.IJMM_20_325 -
Systematic Biology Aug 2023Accurate phylogenies are fundamental to our understanding of the pattern and process of evolution. Yet, phylogenies at deep evolutionary timescales, with correspondingly...
Accurate phylogenies are fundamental to our understanding of the pattern and process of evolution. Yet, phylogenies at deep evolutionary timescales, with correspondingly long branches, have been fraught with controversy resulting from conflicting estimates from models with varying complexity and goodness of fit. Analyses of historical as well as current empirical datasets, such as alignments including Microsporidia, Nematoda, or Platyhelminthes, have demonstrated that inadequate modeling of across-site compositional heterogeneity, which is the result of biochemical constraints that lead to varying patterns of accepted amino acids along sequences, can lead to erroneous topologies that are strongly supported. Unfortunately, models that adequately account for across-site compositional heterogeneity remain computationally challenging or intractable for an increasing fraction of contemporary datasets. Here, we introduce "compositional constraint analysis," a method to investigate the effect of site-specific constraints on amino acid composition on phylogenetic inference. We show that more constrained sites with lower diversity and less constrained sites with higher diversity exhibit ostensibly conflicting signals under models ignoring across-site compositional heterogeneity that lead to long-branch attraction artifacts and demonstrate that more complex models accounting for across-site compositional heterogeneity can ameliorate this bias. We present CAT-posterior mean site frequencies (PMSF), a pipeline for diagnosing and resolving phylogenetic bias resulting from inadequate modeling of across-site compositional heterogeneity based on the CAT model. CAT-PMSF is robust against long-branch attraction in all alignments we have examined. We suggest using CAT-PMSF when convergence of the CAT model cannot be assured. We find evidence that compositionally constrained sites are driving long-branch attraction in two metazoan datasets and recover evidence for Porifera as the sister group to all other animals. [Animal phylogeny; cross-site heterogeneity; long-branch attraction; phylogenomics.].
Topics: Animals; Phylogeny; Bias; Microsporidia; Models, Genetic
PubMed: 36946562
DOI: 10.1093/sysbio/syad013 -
PLoS Pathogens Dec 2023Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming...
Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming industry. Nosema bombycis is a typical microsporidium that infects multiple lepidopteran insects via fecal-oral and transovarial transmission (TOT); however, the underlying TOT processes and mechanisms remain unknown. Here, we characterized the TOT process and identified key factors enabling N. bombycis to invade the ovariole and oocyte of silkworm Bombyx mori. We found that the parasites commenced with TOT at the early pupal stage when ovarioles penetrated the ovary wall and were exposed to the hemolymph. Subsequently, the parasites in hemolymph and hemolymph cells firstly infiltrated the ovariole sheath, from where they invaded the oocyte via two routes: (I) infecting follicular cells, thereby penetrating oocytes after proliferation, and (II) infecting nurse cells, thus entering oocytes following replication. In follicle and nurse cells, the parasites restructured and built large vacuoles to deliver themselves into the oocyte. In the whole process, the parasites were coated with B. mori vitellogenin (BmVg) on their surfaces. To investigate the BmVg effects on TOT, we suppressed its expression and found a dramatic decrease of pathogen load in both ovarioles and eggs, suggesting that BmVg plays a crucial role in the TOT. Thereby, we identified the BmVg domains and parasite spore wall proteins (SWPs) mediating the interaction, and demonstrated that the von Willebrand domain (VWD) interacted with SWP12, SWP26 and SWP30, and the unknown function domain (DUF1943) bound with the SWP30. When disrupting these interactions, we found significant reductions of the pathogen load in both ovarioles and eggs, suggesting that the interplays between BmVg and SWPs were vital for the TOT. In conclusion, our study has elucidated key aspects about the microsporidian TOT and revealed the key factors for understanding the molecular mechanisms underlying this transmission.
Topics: Animals; Humans; Vitellogenins; Spores, Fungal; Nosema; Bombyx
PubMed: 38060601
DOI: 10.1371/journal.ppat.1011859 -
Archives of Razi Institute Aug 2022Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic...
Pebrine disease is the most important and dangerous disease of silkworm caused by as an obligate intracellular parasitic fungus. It has caused tremendous economic losses in the silk industry in recent years. Given the fact that light microscopy method (with low accuracy) is the only method for diagnosing pebrine disease in the country, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods were adopted in this study for accurate morphological identification of the spores causing pebrine disease. Infected larvae and mother moth samples were collected from several farms (Parand, Parnian, Shaft, and Iran Silk Research Center in Gilan province, Iran). The spores were then purified using the sucrose gradient method. From each region, 20 and 10 samples were prepared for SEM and TEM analysis, respectively. In addition, an experiment was performed to evaluate the symptoms of pebrine disease by treating fourth instars with the spores purified for the present study, along with a control group. The results of SEM analysis showed that the mean±SD length and width of spores were 1.99±0.25 to 2.81±0.32 μm, respectively. Based on the obtained results, the size of spores was smaller than the () as the classic species that cause pebrine disease. In addition, transmission electron microscopy (TEM) pictures showed that the grooves of the adult spores were deeper than those of other species, Vairomorpha, and Pleistophora, and resembled in other studies. Examination of pathogenicity of the studied spores indicated that the disease symptoms in controlled conditions were similar to those in the sampled farms. The most important symptom in fourth and fifth instrars were the small size and no growth in the treatment group compared with the control group. Findings of SEM and TEM analysis showed better morphological and structural details of parasite compared with light microscopy, and demonstrated that the studied species were a native strain of specific to Iran, whose size and other characteristics were unique and introduced for the first time in this study.
Topics: Animals; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nosema
PubMed: 36883157
DOI: 10.22092/ARI.2022.356482.1853 -
Acta Parasitologica Mar 2022Most eukaryotic cells have a plasma membrane with glycoproteins on the outer leaflet and cytoplasmic proteins on the inner leaflet. However, the microsporidians examined... (Review)
Review
PURPOSE
Most eukaryotic cells have a plasma membrane with glycoproteins on the outer leaflet and cytoplasmic proteins on the inner leaflet. However, the microsporidians examined have a peculiar outer membrane with cytoplasmic proteins on the surface. His study was to determine if this is true and identify the presence of key cytoplasmic proteins on the exterior of the sporoplasm and spore stages.
METHODS
Specific probes including GFP-labeled genes, antibodies, and electron microscopy were applied to studies on the sporoplasm and spore stages of different microsporidian species.
RESULTS
Cytoplasmic membrane proteins cadherin, intermediate filaments, dynactin p150Glued and tubulin were identified on the outer leaflet of the exterior membrane of the sporoplasm or spore stages of Spraguea americanus, Anncaliia algerae, Ameson michaelis and Thelohania sp.
CONCLUSION
The invasive sporoplasm stage of microsporidians acquires an outer membrane from a cytoplasmic organelle and it has been shown that the outside surface of this membrane bears cytoplasmic proteins. This membrane retains these cytoplasmic proteins even on the spore stage. For an intracellular parasite that locates directly within the cytoplasm of a host cell, the presence of these cytoplasmic proteins on the surface of the parasite appears to have a significant effect on the host's response.
Topics: Cell Membrane; Cytoplasm; Microsporidia
PubMed: 34264441
DOI: 10.1007/s11686-021-00446-9 -
The Ocular Surface Apr 2023Ocular microsporidiosis comprises two entirely different spectra of disease as keratoconjunctivitis and stromal keratitis. Microsporidial keratoconjunctivitis (MKC) has... (Review)
Review
Ocular microsporidiosis comprises two entirely different spectra of disease as keratoconjunctivitis and stromal keratitis. Microsporidial keratoconjunctivitis (MKC) has been increasingly reported in the past two decades, probably due to raised awareness, simpler diagnostic procedures, and a better understanding of the clinical presentation. It is characterized by the presence of raised, coarse, punctate, multifocal, round to oval, greyish-white corneal epithelial lesions which usually evolve into nummular scars before resolution. Conjunctivitis seen is non-purulent and of mild-moderate intensity, with mixed papillary-follicular reaction. The mode of transmission and pathogenesis is poorly understood. Despite lack of inflammatory response, uncommon associations reported were- endotheliitis, corneal edema, limbitis, uveitis, and sub-epithelial infiltrates. There has been no consensus on the management of MKC. It varies from the use of multiple antimicrobial agents to simple lubricants. The majority of the disease goes underdiagnosed or misdiagnosed and treated as adenoviral keratoconjunctivitis, with topical steroids or anti-virals empirically. Changing trends have been noticed in the pattern of infection, possibly with increasing evidence of Vittaforma corneae as causative organisms, previously reported to cause stromal keratitis. An elaborate review of the past and present literature on MKC is provided in this review article, along with gaps in knowledge, and future directions of research.
Topics: Microsporidia; Microsporidiosis; Keratoconjunctivitis; Eye
PubMed: 34419638
DOI: 10.1016/j.jtos.2021.08.008 -
Microbiology Spectrum Dec 2023There are a few reports on the resistance of microsporidia, including . Here, the alkali-soluble germination proteins of were used as immunogens to prepare a monoclonal...
There are a few reports on the resistance of microsporidia, including . Here, the alkali-soluble germination proteins of were used as immunogens to prepare a monoclonal antibody, and its single-chain variable fragments effectively blocked microsporidia infection. Our study has provided novel strategies for microsporidiosis control and demonstrated a useful method for the potential treatment of other microsporidia diseases.
Topics: Animals; Bombyx; Nosema; Microsporidiosis; Antibodies, Monoclonal; Spores; Cell Proliferation
PubMed: 37811955
DOI: 10.1128/spectrum.00681-23 -
Genome Biology and Evolution Jan 2021Microsporidia are obligate intracellular eukaryotic parasites of vertebrates and invertebrates. Microsporidia are usually pathogenic and undergo horizontal transmission...
Microsporidia are obligate intracellular eukaryotic parasites of vertebrates and invertebrates. Microsporidia are usually pathogenic and undergo horizontal transmission or a mix of horizontal and vertical transmission. However, cases of nonpathogenic microsporidia, strictly vertically transmitted from mother to offspring, have been reported in amphipod crustaceans. Some of them further evolved the ability to feminize their nontransmitting male hosts into transmitting females. However, our understanding of the evolution of feminization in microsporidia is hindered by a lack of genomic resources. We report the sequencing and analysis of three strictly vertically transmitted microsporidia species for which feminization induction has been demonstrated (Nosema granulosis) or is strongly suspected (Dictyocoela muelleri and Dictyocoela roeselum), along with a draft genome assembly of their host Gammarus roeselii. Contrary to horizontally transmitted microsporidia that form environmental spores that can be purified, feminizing microsporidia cannot be easily isolated from their host cells. Therefore, we cosequenced symbiont and host genomic DNA and devised a computational strategy to obtain genome assemblies for the different partners. Genomic comparison with feminizing Wolbachia bacterial endosymbionts of isopod crustaceans indicated independent evolution of feminization in microsporidia and Wolbachia at the molecular genetic level. Feminization thus represents a remarkable evolutionary convergence of eukaryotic and prokaryotic microorganisms. Furthermore, a comparative genomics analysis of microsporidia allowed us to identify several candidate genes for feminization, involving functions such as DNA binding and membrane fusion. The genomic resources we generated contribute to establish Gammarus roeselii and its microsporidia symbionts as a new model to study the evolution of symbiont-mediated feminization.
Topics: Amphipoda; Animals; Female; Feminization; Genomics; Host-Parasite Interactions; Male; Microsporidia; Nosema; Phylogeny; Wolbachia
PubMed: 33216144
DOI: 10.1093/gbe/evaa245