For the small number of RON11 knockdown parasites that make it to the salivary gland, we found they accumulate in the space between epithelial cells but almost never actually invade or get into the secretory cavity. This interesting observation explains why these parasites are not transmissible!

More important though, these RON11 knockdown sporozoites only made half the number of rhoptries. And when we looked at the small number of sporozoites that made it to the salivary gland, many of them had no rhoptries at all!

Looking at these RON11 knockdown parasites, we saw that late in their rhoptry biogenesis, most of them had aberrant looking rhoptries.

One unexpected observation was that of the usually 2 pairs of rhoptries in oocyst sporozoites, they were morphologically distinguishable. We called these the dimorphic (different size) and congruent (same size) rhoptry pairs, with the congruent rhoptries specifically used up during SG invasion.

Wanting to follow the fate of rhoptries through the invasion of sporozoites into the mosquito salivary gland, we could differentiate sporozoites at different stages of this process. Excitingly, we could see that sporozoites use up two rhoptries during salivary gland epithelial cell invasion!

We then put the segmentation score to the test, using it to develop a timeline for the biogenesis of rhoptries in forming sporozoites!

In the past, oocyst size was used a proxy for development, but one sporozoite formation started, we saw no real correlation with developmental stage and oocyst size. Instead we developed what we call the segmentation score, using progress through cytokinesis as a way to assess sporozoite development

Next, we wanted to look at how sporozoites form within the oocyst. But we ran into a problem, oocysts from the same midgut varied massively in their progress through sporozoite development. So how can we compare different oocysts with each other?

We could see plenty of other organelles/structures in oocysts too, like the basal complex, apicoplast, apical polar rings, rhoptries, centriolar plaque and more!

Having seen how powerful expansion microscopy was for studying other aspects of parasite biology, we were really keen to see what this technique could allow us to see in mosquito-stage parasites. Being good cell biologists, we first looked at the cool microtubule spindle structures of oocysts!

Would have loved to be able to be there in person, but excited and proud to see a great colleague and a great friend in James Blauwkamp deliver a fantastic PhD Defence!

Been a wonderful experience to see you grow as a scientist over the years and excited to see what's next 🎉
@sabsalon.bsky.social

Great to get the opportunity to present our work on expansion microscopy of mosquito-stage malaria parasites at Lorne I&I this morning!
Cheers to @theviin.bsky.social for the ECR award that allowed me to attend this meeting #LorneIandI

A real honour to receive the inaugural Kat Gaus Award at APMC13 last week @australianmms.bsky.social supported by Zeiss Microscopy Australia & New Zealand.

Cheers to everybody for supporting me doing weird and wonderful light microscopy experiments on parasites over the years!

A massive thanks to @sturalph.bsky.social @ijayas.bsky.social, Donna Whelan, Ashley Rozario, and Dawson Ling for a fantastic session and discussion on expansion microscopy yesterday at #APMC13

Starting the new year from a different office 🐑

A massive thank you to the Tonkin Lab for hosting me at @wehi-research.bsky.social over the past month to learn about all things Crypto!

Looking forward to seeing you all again soon!