scholarly journals A Comparison of Stage Conversion in the Coccidian Apicomplexans Toxoplasma gondii, Hammondia hammondi, and Neospora caninum

2020 ◽  
Vol 10 ◽  
Author(s):  
Sarah L. Sokol-Borrelli ◽  
Rachel S. Coombs ◽  
Jon P. Boyle
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Stress Responses ◽  
Neospora Caninum ◽  
Life Forms ◽  
New Host ◽  
Environmental Signals ◽  
Stage Conversion ◽  
Genetic Components ◽  
Species Specific

Stage conversion is a critical life cycle feature for several Apicomplexan parasites as the ability to switch between life forms is critical for replication, dissemination, pathogenesis and ultimately, transmission to a new host. In order for these developmental transitions to occur, the parasite must first sense changes in their environment, such as the presence of stressors or other environmental signals, and then respond to these signals by initiating global alterations in gene expression. As our understanding of the genetic components required for stage conversion continues to broaden, we can better understand the conserved mechanisms for this process and unique components and their contribution to pathogenesis by comparing stage conversion in multiple closely related species. In this review, we will discuss what is currently known about the mechanisms driving stage conversion in Toxoplasma gondii and its closest relatives Hammondia hammondi and Neospora caninum. Work by us and others has shown that these species have some important differences in the way that they (1) progress through their life cycle and (2) respond to stage conversion initiating stressors. To provide a specific example of species-specific complexities associated with stage conversion, we will discuss our recent published and unpublished work comparing stress responses in T. gondii and H. hammondi.

scholarly journals Importance of serological cross-reactivity amongToxoplasma gondii, Hammondiaspp.,Neosporaspp.,Sarcocystisspp. andBesnoitia besnoiti

Parasitology ◽  
2017 ◽  
Vol 144 (7) ◽  
pp. 851-868 ◽  
Author(s):  
LUÍS F. P. GONDIM ◽  
JOSÉ R. MINEO ◽  
GEREON SCHARES
Keyword(s):  
Toxoplasma Gondii ◽  
Neospora Caninum ◽  
Cross Reactivity ◽  
Besnoitia Besnoiti ◽  
Cross Reactions ◽  
Epidemiological Surveys ◽  
Specific Proteins ◽  
Specific Antigens ◽  
Species Specific

SUMMARYToxoplasma gondii, Neosporaspp.,Sarcocystisspp.,Hammondiaspp. andBesnoitia besnoitiare genetically related cyst-forming coccidia. Serology is frequently used for the identification ofT. gondii, Neosporaspp. andB. besnoiti-exposed individuals. Serologic cross-reactions occur in different tests among animals infected withT. gondiiandH. hammondi,as well as among animals infected byT. gondiiandN. caninum. Infections caused byN. caninumandN. hughesiare almost indistinguishable by serology.Neospora caninum, B. besnoitiandSarcocystisspp. infections in cattle show some degree of serologic cross-reactivity. Antibody cross-reactivity betweenNeosporaspp. andH. heydorni-infected animals is suspected, but not proven to occur. We review serologic cross-reactivity among animals and/or humans infected withT. gondii, Neosporaspp.,Sarcocystisspp.,Hammondiaspp. andB. besnoiti. Emphasis is laid upon antigens and serological methods forN. caninumdiagnosis which were tested for cross-reactivity with related protozoa. Species-specific antigens, as well as stage-specific proteins have been identified in some of these parasites and have promising use for diagnosis and epidemiological surveys.

scholarly journals Differential Locus Expansion Distinguishes Toxoplasmatinae Species and Closely Related Strains of Toxoplasma gondii

mBio ◽  
2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Yaw Adomako-Ankomah ◽  
Gregory M. Wier ◽  
Adair L. Borges ◽  
Hannah E. Wand ◽  
Jon P. Boyle
Keyword(s):  
Toxoplasma Gondii ◽  
Gene Duplication ◽  
Copy Number ◽  
Neospora Caninum ◽  
Comparative Genomic ◽  
Transcriptional Level ◽  
World Population ◽  
Content Type ◽  
Phenotypic Differences ◽  
Species Specific

ABSTRACT Toxoplasma gondii is a human obligate intracellular parasite that has infected over 20% of the world population and has a vast intermediate host range compared to those of its nearest relatives Neospora caninum and Hammondia hammondi. While these 3 species have highly syntenic genomes (80 to 99%), in this study we examined and compared species-specific structural variations, specifically at loci that have undergone local (i.e., tandem) duplication and expansion. To do so, we used genomic sequence coverage analysis to identify and curate T. gondii and N. caninum loci that have undergone duplication and expansion (expanded loci [ELs]). The 53 T. gondii ELs are significantly enriched for genes with predicted signal sequences and single-exon genes and genes that are developmentally regulated at the transcriptional level. We validated 24 T. gondii ELs using comparative genomic hybridization; these data suggested significant copy number variation at these loci. High-molecular-weight Southern blotting for 3 T. gondii ELs revealed that copy number varies across T. gondii lineages and also between members of the same clonal lineage. Using similar methods, we identified 64 N. caninum ELs which were significantly enriched genes belonging to the SAG-related surface (SRS) antigen family. Moreover, there is significantly less overlap (30%) between the expanded gene sets in T. gondii and N. caninum than would be predicted by overall genomic synteny (81%). Consistent with this finding, only 59% of queried T. gondii ELs are similarly duplicated/expanded in H. hammondi despite over 99% genomic synteny between these species. IMPORTANCE Gene duplication, expansion, and diversification are a basis for phenotypic differences both within and between species. This study represents the first characterization of both the extent and degree of overlap in gene duplication and locus expansion across multiple apicomplexan parasite species. The most important finding of this study is that the locus duplications/expansions are quantitatively and qualitatively distinct, despite the high degree of genetic relatedness between the species. Given that these differential expansions are prominent species-specific genetic differences, they may also contribute to some of the more striking phenotypic differences between these species. More broadly, this work is important in providing further support for the idea that postspeciation selection events may have a dramatic impact on locus structure and copy number that overshadows selection on single-copy genes.

scholarly journals Differential protein phosphorylation affects the localisation of two secreted Toxoplasma proteins and is widespread during stage conversion

2020 ◽  
Author(s):  
Joanna Young ◽  
Malgorzata Broncel ◽  
Helena Teague ◽  
Matt Russell ◽  
Olivia McGovern ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Cyst Wall ◽  
Parasitophorous Vacuole ◽  
Proteome Analysis ◽  
Cyst Formation ◽  
Secreted Proteins ◽  
New Host ◽  
Chronic Stage ◽  
Stage Conversion ◽  
Membrane Bound

ABSTRACTThe intracellular parasite Toxoplasma gondii resides within a membrane bound parasitophorous vacuole (PV) and secretes an array of proteins to establish this replicative niche. It has been shown previously that Toxoplasma both secretes kinases and that numerous proteins are phosphorylated after secretion. Here we assess the role of phosphorylation of SFP1 and the related GRA29, two secreted proteins with unknown function. We show that both proteins form stranded structures in the PV that are independent of the previously described intravacuolar network or actin. GRA29 likely acts as a seed for SFP1 strand formation, and these structures can form independently of other Toxoplasma secreted proteins. We show that an unstructured region at the C-terminus of SFP1 and GRA29 is required for the formation of strands and that mimicking phosphorylation of this domain negatively regulates strand development. When tachyzoites convert to chronic stage bradyzoites, both proteins show a dispersed localisation throughout the cyst matrix. Many secreted proteins are reported to dynamically redistribute as the cyst forms and secreted kinases are known to play a role in cyst formation. Using quantitative phosphoproteome and proteome analysis comparing tachyzoite and early bradyzoite stages, we reveal widespread differential phosphorylation of secreted proteins. These data support a model in which secreted kinases and phosphatases are important to dynamically regulate parasite secreted proteins during stage conversion.IMPORTANCEToxoplasma gondii is a common parasite that infects up to one third of the human population. Initially the parasite grows rapidly, infecting and destroying cells of the host, but subsequently switches to a slow-growing form and establishes chronic infection. In both stages the parasite lives within a membrane bound vacuole within the host cell, but in the chronic stage a durable cyst wall is synthesized that provides protection to the parasite during transmission to a new host. Toxoplasma secretes proteins into the vacuole to build its replicative niche and previous studies identified many of these proteins as phosphorylated. We investigate two secreted proteins and show that phosphorylation plays an important role in their regulation. We also observed widespread phosphorylation of secreted proteins when parasites convert from acute to chronic stages, providing new insight into how the cyst wall may be dynamically regulated.

scholarly journals Biology and engineering of integrative and conjugative elements: Construction and analyses of hybrid ICEs reveal element functions that affect species-specific efficiencies

2021 ◽  
Author(s):  
Emily L Bean ◽  
Calvin Herman ◽  
Alan D. Grossman
Keyword(s):  
Life Cycle ◽  
High Efficiency ◽  
Bacterial Host ◽  
New Host ◽  
Host Chromosome ◽  
Integrative And Conjugative Elements ◽  
New Hosts ◽  
Species Specific ◽  
Regulatory Functions ◽  
Efficient Transfer

Integrative and conjugative elements (ICEs) are mobile genetic elements that reside in a bacterial host chromosome and are prominent drivers of bacterial evolution. They are also powerful tools for genetic analyses and engineering. Transfer of an ICE to a new host involves many steps, including excision from the chromosome, DNA processing and replication, transfer across the envelope of the donor and recipient, processing of the DNA, and eventual integration into the chromosome of the new host (now a stable transconjugant). Interactions between an ICE and its hosts throughout the life cycle likely influence the efficiencies of acquisition by new hosts. Here, we investigated how different functional modules of two ICEs, Tn916 and ICEBs1, affect the transfer efficiencies into different host bacteria. We constructed hybrid elements that utilize the high-efficiency regulatory and excision modules of ICEBs1 and the conjugation genes of Tn916. These elements produced more transconjugants than Tn916, likely due to increased excision frequencies. We also found that several Tn916 and ICEBs1 components can substitute for one other. Using B. subtilis donors and three Enterococcus species as recipients, we found that different hybrid elements were more readily acquired by some species than others, demonstrating species-specific interactions in steps of the ICE life cycle. This work demonstrates that hybrid elements utilizing the efficient regulatory functions of ICEBs1 can be built to enable efficient transfer into and engineering of a variety of other species.

scholarly journals Dissection of the in vitro developmental program of Hammondia hammondi reveals a link between stress sensitivity and life cycle flexibility in Toxoplasma gondii

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Sarah L Sokol ◽  
Abby S Primack ◽  
Sethu C Nair ◽  
Zhee S Wong ◽  
Maiwase Tembo ◽  
...  
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Stress Responses ◽  
Cyst Formation ◽  
Stress Sensitivity ◽  
Stress Exposure ◽  
Developmental Program ◽  
Dramatic Difference ◽  
Sequential Infection

Most eukaryotic parasites are obligately heteroxenous, requiring sequential infection of different host species in order to survive. Toxoplasma gondii is a rare exception to this rule, having a uniquely facultative heteroxenous life cycle. To understand the origins of this phenomenon, we compared development and stress responses in T. gondii to those of its its obligately heteroxenous relative, Hammondia hammondi and have identified multiple H. hammondi growth states that are distinct from those in T. gondii. Of these, the most dramatic difference was that H. hammondi was refractory to stressors that robustly induce cyst formation in T. gondii, and this was reflected most dramatically in its unchanging transcriptome after stress exposure. We also found that H. hammondi could be propagated in vitro for up to 8 days post-excystation, and we exploited this to generate the first ever transgenic H. hammondi line. Overall our data show that H. hammondi zoites grow as stringently regulated, unique life stages that are distinct from T. gondii tachyzoites, and implicate stress sensitivity as a potential developmental innovation that increased the flexibility of the T. gondii life cycle.

scholarly journals Hammondia hammondihas a developmental programin vitrothat mirrors its stringent two host life cycle

2017 ◽  
Author(s):  
Sarah L. Sokol ◽  
Abby S. Primack ◽  
Sethu C. Nair ◽  
Zhee S. Wong ◽  
Maiwase Tembo ◽  
...  
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Specific Growth ◽  
Cyst Formation ◽  
Host Cells ◽  
Tissue Cyst ◽  
Life Stages ◽  
New Host ◽  
Host Life

AbstractHammondia hammondiis the nearest relative ofToxoplasma gondii,but unlikeT. gondiiis obligately heteroxenous. We have comparedH. hammondiandT. gondiidevelopmentin vitroand identified multipleH. hammondi-specific growth states. Despite replicating slower thanT. gondii,H. hammondiwas resistant to pH-induced tissue cyst formation early after excystation. However, in the absence of stressH. hammondispontaneously converted to a terminally differentiated tissue cyst stage whileT. gondiidid not. CulturedH. hammondicould infect new host cells for up to 8 days following excystation, and this period was exploited to generate stably transgenicH. hammondi. Coupled with RNAseq analyses, our data clearly show thatH. hammondizoites grow as stringently regulated life stages that are fundamentally distinct fromT. gondiitachyzoites and bradyzoites.

Oocyst-Induced Murine Toxoplasmosis: Life Cycle, Pathogenicity, and Stage Conversion in Mice Fed Toxoplasma gondii Oocysts

1997 ◽  
Vol 83 (5) ◽  
pp. 870 ◽  
Author(s):  
J. P. Dubey ◽  
C. A. Speer ◽  
S. K. Shen ◽  
O. C. H. Kwok ◽  
J. A. Blixt
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Stage Conversion

scholarly journals Metabolic reprogramming during the Trypanosoma brucei life cycle

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 683 ◽  
Author(s):  
Terry K. Smith ◽  
Frédéric Bringaud ◽  
Derek P. Nolan ◽  
Luisa M. Figueiredo
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Model Organism ◽  
Protozoan Parasite ◽  
Tsetse Fly ◽  
Metabolic Reprogramming ◽  
Mammalian Host ◽  
Insect Vector ◽  
Environmental Signals ◽  
Cellular Metabolic Activity

Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.

scholarly journals Versatile Physiological Functions of Plant GSK3-Like Kinases

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 697
Author(s):  
Juan Mao ◽  
Wenxin Li ◽  
Jing Liu ◽  
Jianming Li
Keyword(s):  
Stress Responses ◽  
Glycogen Synthase ◽  
Plant Stress ◽  
Normal Growth ◽  
Growth Conditions ◽  
Genetic Studies ◽  
Physiological Functions ◽  
Environmental Signals ◽  
Plant Stress Responses ◽  
Diverse Plant

The plant glycogen synthase kinase 3 (GSK3)-like kinases are highly conserved protein serine/threonine kinases that are grouped into four subfamilies. Similar to their mammalian homologs, these kinases are constitutively active under normal growth conditions but become inactivated in response to diverse developmental and environmental signals. Since their initial discoveries in the early 1990s, many biochemical and genetic studies were performed to investigate their physiological functions in various plant species. These studies have demonstrated that the plant GSK3-like kinases are multifunctional kinases involved not only in a wide variety of plant growth and developmental processes but also in diverse plant stress responses. Here we summarize our current understanding of the versatile physiological functions of the plant GSK3-like kinases along with their confirmed and potential substrates.

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