Defense of Patrícia Diogo

On 18th October, Ákos has participated as a member of the examination committee in the defense of the dissertation entitled “Cryopreservation of zebrafish germ cells: technological improvements and methodological standardization for gene banking and management” by Patrícia Diogo at the University of Algarve in Faro, Portugal. Patrícia was a PhD student of our friends Dr. Elsa Cabrita and Dr. Paulo Gavaia and a member of the Aquagroup at the same university and the Centre of Marine Sciences (CCMAR). She gave an excellend presentation of her results and convinced the committee of her profound knowledge in the area of her studies. Congratulations, Dr. Diogo!

Patrícia Diogo (center) with members of the committee (Dr. Paulo Gavaia, Ákos, Dr. Elsa Cabrita, Dr. Catarina Oliveira, Dr. Juan F. Asturiano and Dr. Sérgio Jesus) following the defense

New paper published in Scientifc Reports

A new paper with the first authorship of Zoran was published in Scientific Reports. Enjoy!

Zoran Marinović, Qian Li, Jelena Lujić, Yoshiko Iwasaki, Zsolt Csenki, Béla Urbányi, Goro Yoshizaki & Ákos Horváth: Preservation of zebrafish genetic resources through testis cryopreservation and spermatogonia transplantation. Scientific Reports volume 9, Article number: 13861 (2019)

Abstract

Zebrafish is one of the most commonly used model organisms in biomedical, developmental and genetic research. The production of several thousands of transgenic lines is leading to difficulties in maintaining valuable genetic resources as cryopreservation protocols for eggs and embryos are not yet developed. In this study, we utilized testis cryopreservation (through both slow-rate freezing and vitrification) and spermatogonia transplantation as effective methods for long-term storage and line reconstitution in zebrafish. During freezing, utilization of 1.3 M of dimethyl sulfoxide (Me2SO) displayed the highest spermatogonia viability (~60%), while sugar and protein supplementation had no effects. Needle-immersed vitrification also yielded high spermatogonia viability rates (~50%). Both optimal slow-rate freezing and vitrification protocols proved to be reproducible in six tested zebrafish lines after displaying viability rates of >50% in all lines. Both fresh and cryopreserved spermatogonia retained their ability to colonize the recipient gonads after intraperitoneal transplantation of vasa::egfp and actb:yfp spermatogonia into wild-type AB recipient larvae. Colonization rate was significantly higher in dnd-morpholino sterilized recipients than in non-sterilized recipients. Lastly, wild-type recipients produced donor-derived sperm and donor-derived offspring through natural spawning. The method demonstrated in this study can be used for long-term storage of valuable zebrafish genetic resources and for reconstitution of whole zebrafish lines which will greatly improve the current preservation practices.

Ákos promoted into professorship

By the Decree 351/2019. (VIII. 30.) of the President of the Republic of Hungary Ákos was appointed as a professor as of 1st September, 2019.

7th International Workshop on the Biology of Fish Gametes

Ákos, Timi, Betti and Nevena have participated at the 7th International Workshop on the Biology of Fish Gametes that was organized between 2-6th September in Rennes, France. As always, the workshop was a wonderful opportunity for scientist working on fish gametes to meet in person and share their newest results. Ákos, Timi and Nevena gave oral presentations durind the sessions while Betti presented a poster. We would like to thank the French colleagues for the wonderful experience and professional organization. Looking forward to seeing everyone in two years in Poland.

Oral presentations by the group:

Tímea Kollár, Bernadett Pataki, Gyöngyi Gazsi, Béla Urbányi, Ákos Horváth: Effect of age on the sensitivity of zebrafish (Danio rerio) sperm

Ákos Horváth, Zoran Marinović, György Hoitsy, Márton Hoitsy, Boglárka Hoitsy, Béla Urbányi, Jelena Lujić: Is the hybrid tiger trout a good recipient for the transplantation of early-stage germ cells?

Ilija Šćekić, Nevena Kitanović, Zoran Marinović, Tamás Müller, Béla Urbányi, Jelena Lujić, Ákos Horváth: Preservation of ovarian tissue in european eel (Anguilla anguilla)

Posters presented or co-authored by the group:

Roman Franěk, Taiju Saito, Tomáš Tichopád, Michaela Fučíková, Zoran Marinović, Jelena Lujić, Ákos Horváth, Vojtěch Kašpar, Martin Pšenička: Germ cell manipulation as a tool for common carp isogenic lines production and management.

Bernadett Pataki, Tímea Kollár, Zoran Marinović, Jelena Lujić, Gyöngyi Gazsi, Roberta Izabella Berta, Béla Urbányi, Ákos Horváth: Inheritance of sperm cryoresistance in zebrafish (Danio rerio)

Frontires in Reproduction: Molecular and Cellular Concepts and Applications (FIR)

Jelena spent six weeks at the Marine Biological Laboratory (University of Chicago) participating in the course Frontires in Reproduction: Molecular and Cellular Concepts and Applications (FIR). During that time, she had lectures in all relevant methods in reproductive biology such as endocrinology, stem cells, gametogenesis, fertilization, sex determination etc. Most of the time was devoted to laboratory practice and performing experiments regarding signalling, CRISPR Cas9, epigenetics, in situ hybridization, tissue and oocyte culture, germ cell transplantation, oocyte maturation, ICSI, IVF, embryo transfer, ESC microinjection, reproductive immunology, placentation etc.

Beside the educational part, this was the perfect opportunity for networking. The course itself has a very long tradition (since 1998) and the FIR community is very significant in the area of reproductive biology and includes scientists from around the world (circa 400 people).

Beside the support of our University, Jelena`s participation was partly funded by the NICHD and the Burroughs Wellcome Fund.

Jelena can now proudly say that she is a FIRbee 😊

FIRbees 2019

FIRbees 2019 with section directors and organizers

Working mode

Mission accomplished - sperm lab

Science is exciting

Chalk talk about fish surrogate production

Wrap up of the labs from the Section 1

Jelena`s presentation at FIR symposium 2019

FIRbees 2019 at the sunset in the Woods Hole

FIRbees 2019 at the closing reception

FIRbees 2019 at the closing reception

FIRbees during the weekend

It is written in stone, no, in the tissue

Grill party and fun

We are big happy family now

Present from dear colleague Augustin

Teaching in Pula and Zagreb, Croatia

On the invitation of our colleague Dr. Ana Gavrilović from the University of Zagreb in Croatia, Ákos has spent the period between May 23-27th in Pula and Zagreb. This included teaching the basics of cryobiology, fish sperm and germ cell cryopreservation and their transplantation to undergraduate students of the University of Pula and to graduate students in Zagreb. The trip was also a good opportunity for Ákos to practice his original qualification of a fisheries and aquaculture person as he joined a fishing expedition with Ana and her student Neven Iveša. As you see in the picture below, the catch was quite abundant and a real professional treat for Ákos.

Ákos giving a presentation in Pula

The catch of the day

New review paper published in Theriogenology

A new review paper with the co-authorship of Ákos has been published in Theriogenology. Enjoy!

Juan German Herranz-Jusdado, Victor Gallego, Marina Morini, Christoffer Rozenfeld, Luz Pérez, Tamás Müller, Ákos Horváth, Hiromi Ohta, Juan F. Asturiano: Eel sperm cryopreservation: An overview. Theriogenology, 133, 210-215. https://doi.org/10.1016/j.theriogenology.2019.03.033

The eels are teleost fishes from the order Anguilliformes that includes several species with high commercial value. Due to the high interest for aquaculture production of some eel species and for the need to restore eel species that are endangered, several research groups have directed their research toward developing protocols to cryopreserve the spermatozoa of Japanese eel (Anguilla japonica) and European eel (Anguilla anguilla). In this review, we provide an overview on the different protocols that have been developed so far. The first developed protocols used DMSO as cryoprotectant in both species with good success, obtaining sperm motilities of over 45% in Japanese eel and over 35% in European eel. Moreover, sperm cryopreserved using DMSO was successfully used in fertilization trials, although with low fertilization rates. However, recent studies show that DMSO produce epigenetic changes in eel sperm and therefore, the last developed protocols used methanol as cryoprotectant instead. Cryopreservation protocols using methanol as cryoprotectant, showed improved motility values in both Japanese and European eel. In addition, the latest protocols have been adapted to cryopreserve larger volumes of sperm of up to 5 mL, which is useful for larger scale fertilization trials.

The present study introduces the state of the art and future perspectives of the eel sperm cryopreservation to be applied in aquaculture and biological conservation programs.

New paper accepted in PlosOne

A new paper in collaboration with our colleagues from University of South Bohemia in Česke Budejovice, Faculty of Fisheries and Protection of Waters (Czech Republic) has been accepted for publication in PlosOne.

Franěk R., Marinović Z., Lujić J., Urbányi B., Fučíková M., Kašpar V., Pšenička M., Horváth Á. 2019. Cryopreservation and transplantation of common carp spermatogonia. PLoS One. 14(4):e0205481. DOI: 10.1371/journal.pone.0205481

Abstract

Common carp (Cyprinus carpio) is one of the most cultured fish species over the world with many different breeds and plenty of published protocols for sperm cryopreservation. However, data regarding preservation of gonadal tissue and surrogate production is still missing. A protocol for freezing common carp spermatogonia was developed through varying different factors along a set of serial subsequent experiments. Among the six cryoprotectants tested, the best survival was achieved with dimethyl sulfoxide (Me2SO). In the next experiment, a wide range of cooling rates (0.5–10°C/min) and different concentrations of Me2SO were tested resulting in the highest survival achieved using 2 M Me2SO and cooling rate of -1°C/min. When testing different tissue sizes and incubation times in the cryomedia, the highest viability was observed when incubating 100 mg tissue fragments for 30 min. Finally, sugar supplementation did not yield significant differences. When testing different equilibration (ES) and vitrification solutions (VS) used for needle-immersed vitrification, no significant differences were observed between the tested groups. Additionally, varied exposure time to VS did not improve the vitrification outcome where the viability was 4-fold lower than that of freezing. The functionality of cryopreserved cells was tested by interspecific transplantation into sterilized goldfish recipients. The exogenous origin of the germ cells in gonads of goldfish recipient was confirmed by molecular markers and incorporation rate was over 40% at 3 months post-transplantation. Results of this study can serve for long-term preservation of germplasm in carp which can be recovered in a surrogate recipient.