First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Kodzo Atchou and Bianca Manuela Berger are co-first authors on ‘ Pre-gelation staining expansion microscopy for visualisation of the Plasmodium liver stage’, published in JCS. Kodzo is a PhD student in the lab of Prof. Dr Volker Heussler at the Institute of Cell Biology, University of Bern, Bern, Switzerland, where he is interested in molecular biology and parasitology with a focus on host–pathogen interaction for the Plasmodium liver stage. Bianca is a PhD student in the lab of Prof. Dr Torsten Ochsenreiter also at the Institute of Cell Biology, University of Bern, where she has a broad interest in molecular biology and parasitology; during her PhD she investigated mitochondrial gene expression in Trypanosoma brucei.

Kodzo Atchou

How would you explain the main findings of your paper in lay terms?

K.A. & B.M.B.:Plasmodium is a unicellular organism that causes the disease malaria. A thorough understanding of both the parasite biology and host–pathogen interactions is crucial to finding new treatment options against the disease. In this study, we developed an expansion microscopy protocol with better imaging resolution in order to investigate the host–parasite interaction throughout the stage of development during which the parasite infects cells in the liver, and gain a deeper understanding of its biology.

Were there any specific challenges associated with this project? If so, how did you overcome them?

K.A. & B.M.B.: When trying to use expansion microscopy on Plasmodium parasites during liver stage development, we initially struggled to get good staining that preserved epitopes using the protocols that have been already published. Therefore, we decided to adapt existing protocols to be able to perform expansion microscopy of the Plasmodium liver stage. After troubleshooting, we finally established our pre-gelation staining expansion microscopy protocol, which results in a very good preservation of epitopes. This timesaving protocol might also be of use in other research areas.

When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?

K.A. & B.M.B.: Our ‘eureka’ moment was when we saw the parasite and host cell organelles nicely expanded using our own protocol for the first time. We were very thrilled about the possible applications of our method to studying the Plasmodium liver stage in greater detail. Additionally, we were pleasantly surprised at how well the parasite mitochondrial network was preserved upon expansion, because Plasmodium mitochondria are very susceptible to stresses, such as those caused by fixation methods, and can easily get disrupted during the denaturation process.

Why did you choose Journal of Cell Science for your paper?

K.A. & B.M.B.: By publishing in this journal, we expect to reach a broad scientific community and hope that the protocol will find applications and uses in other organisms. Our labs have previously had a very good experience publishing in Journal of Cell Science. Furthermore, the research areas covered by the journal make it a good fit for our study.

Bianca Manuela Berger

Bianca Manuela Berger

Expansion microscopy image of a HeLa cell infected with a Plasmodium berghei parasite (fixed at 48 h post infection). Host cell lysosomes were stained with anti-LAMP1 (green) and are visible as round vesicles fusing to the Plasmodium berghei parasitophorous vacuole membrane (PVM) stained with anti-UIS4 (magenta). Scale bar: 10 µm.

Expansion microscopy image of a HeLa cell infected with a Plasmodium berghei parasite (fixed at 48 h post infection). Host cell lysosomes were stained with anti-LAMP1 (green) and are visible as round vesicles fusing to the Plasmodium berghei parasitophorous vacuole membrane (PVM) stained with anti-UIS4 (magenta). Scale bar: 10 µm.

Have you had any significant mentors who have helped you beyond supervision in the lab? How was their guidance special?

K.A. & B.M.B.: Our supervisors, Prof. Dr Volker Heussler and Prof. Dr Torsten Ochsenreiter, have helped us over the past couple of years to mature scientifically. They supported us in developing our own ideas and experiments and have been always there for scientific advice and support. Although our labs are working on two different parasites − the Volker Lab's focus is on Plasmodium, whereas the Torsten Lab's research looks at Trypanosoma − they gave us the chance to do this great project together. We are also grateful to the members of Volker's and Torsten's labs for providing a very good and supportive lab atmosphere.

What motivated you to pursue a career in science, and what have been the most interesting moments on the path that led you to where you are now?

K.A.: Coming from a sub-Saharan African country, I have a strong motivation to study malaria, as it affects millions of people every year, with children and pregnant women being the most susceptible. I am generally interested in infectious diseases, as I enjoy working in a field in which research might enable translational applications for clinics and thereby have a positive impact on the lives of people.

B.M.B.: With a similar motivation to Kodzo, I am also interested in studying parasites. My model organism, Trypanosoma brucei, is the causative agent of sleeping sickness, which is a neglected tropical disease. Our mutual interest in parasitology led us to forming a team and working together on the expansion microscopy protocol to better understand the Plasmodium liver stage.

Who are your role models in science? Why?

K.A.: My first role model in science is Prof. Dr Volker Heussler. During his own studies, Volker spent time in Africa working on different parasites, such as Theileria. A great professor and mentor, he shows extreme commitment and enthusiasm, and supports the group with weekly meetings and discussions. My second role model is Louis Agassiz; I admire his high sense of observation.

B.M.B.: My role models are strong female scientists who manage their career on top of having a family; for example, Dr Gaelle Lentini, who just started her position as group leader in the Institute of Cell Biology at the University of Bern and is mother of two young daughters. Women who do amazing science and at the same time do not cut short their family time are a strong source of encouragement and motivation for me.

What's next for you?

K.A. & B.M.B.: The next step for each of us is to pursue a postdoc focusing on infectious, vector-born and neglected diseases. The dream would be to one day have our own lab, working together on parasitology.

Tell us something interesting about yourself that wouldn't be on your CV

K.A. & B.M.B.: Kodzo likes playing football, dancing and watching scientific documentaries, while Bianca loves hiking, spending time in nature and reading. We love cooking and gardening together. When not in the lab, we travel around Switzerland together and love helping out on farms.

Kodzo Atchou’s and Bianca Manuela Berger's contact details: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.

E-mails: kodzo.atchou@unibe.ch; bianca.berger@unibe.ch

Atchou
,
K.
,
Berger
,
B. M.
,
Heussler
,
V.
and
Ochsenreiter
,
T.
(
2023
).
Pre-gelation staining expansion microscopy for visualisation of the Plasmodium liver stage
.
J. Cell Sci.
136
,
jcs261377
.