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ABSTRACT The body plan of the human parasite Toxoplasma gondii has a well-defined polarity. The minus ends of the 22 cortical microtubules are anchored to the apical polar ring, which is a putative microtubule-organizing center. The basal complex caps and constricts the parasite posterior end and is crucial for cytokinesis. How this apical–basal polarity is initiated is unknown. Here, we have examined the development of the apical polar ring and the basal complex using expansion microscopy. We found that substructures in the apical polar ring have different sensitivities to perturbations. In addition, apical–basal differentiation is already established upon nucleation of the cortical microtubule array: arc forms of the apical polar ring and basal complex associate with opposite ends of the microtubules. As the nascent daughter framework grows towards the centrioles, the apical and basal arcs co-develop ahead of the microtubule array. Finally, two apical polar ring components, APR2 and KinesinA, act synergistically. The removal of individual proteins has a modest impact on the lytic cycle. However, the loss of both proteins results in abnormalities in the microtubule array and in highly reduced plaquing and invasion efficiency.
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A leaky human colon model reveals uncoupled apical/basal cytotoxicity in early Clostridioides difficile toxin exposure
Novel human colonocyte monolayer cultures, benchmarked by transcriptomics for physiological relevance, detect early cytopathic impacts of Clostridioides difficile toxins TcdA and TcdB. A fluorescent ZO-1 reporter in primary human colonocytes is used to track epithelial barrier disruption in response to TcdA. Basal TcdA/B exposure generally caused more rapid onset and cytotoxicity than apical exposure. Transcriptomics demonstrate changes in tight junction, chemokine, and cytokine receptor gene expression post-TcdA exposure. Diclofenac-induced leaky epithelium enhanced apical exposure toxicity.
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- Award ID(s):
- 1934284
- PAR ID:
- 10477390
- Publisher / Repository:
- American Journal of Physiology-Gastrointestinal and Liver Physiology
- Date Published:
- Journal Name:
- American Journal of Physiology-Gastrointestinal and Liver Physiology
- Volume:
- 324
- Issue:
- 4
- ISSN:
- 0193-1857
- Page Range / eLocation ID:
- G262 to G280
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1152/ajpgi.00251.2022
