New paper accepted in Reproduction in Domestic Animals

A new paper of our group was accepted for publication in the journal `Reproduction in Domestic Animals`.

Lujić J., Marinović Z., Kása E., Šćekić I., Urbányi B., Horváth Á. 2018. Preservation of common carp germ cells under hypothermic conditions: whole tissue vs isolated cells. Reproduction in Domestic Animals. 
The aim of this study was to optimize the conditions for hypothermic storage of spermatogonial stem cells (SSCs) and oogonial stem cells (OSCs) of common carp Cyprinus carpio. This was conducted by storing gonadal tissue or isolated cells for 24 h under hypothermic conditions in the first experiment and by testing two different storage media (L-15 or DMEM supplemented with 10% FBS and 25 mM HEPES) and regular medium change (every 4 days) during two weeks of hypothermic storage in the second experiment. During the first 24 h, isolated cells showed no decrease in viability while cells obtained from hypothermically stored tissues displayed significantly lower viability after only 6 h (Tukey’s HSD, p < 0.01) indicating that hypothermic storage of isolated cells is superior to storing tissue pieces. The two-week trial demonstrated that storage media have a profound influence,
while regular medium exchange does not have a positive effect on cell viability. Viability of SSCs and OSCs after two weeks was approximately 40% and 25%, respectively, however survival of ~ 70% was obtained after 10 days of storage for SSCs and 7 days for OSCs. Hypothermic storage developed in this study has many practical applications during the development of surrogate broodstock technologies for common carp, but also in different carp hatcheries and for the conservation of genetic resources of closely related cyprinid species.


Master thesis defense of Nataša Cvetković

One of our students from Serbia, Nataša Cvetković, successfuly finished and defended her Master thesis `Vitification of testicular tissue of zebrafish (Danio rerio)` at the Department of Biology and Ecology of the Faculty of Sciences at the University of Novi Sad in Serbia. She spent with us more than one month working in our laboratories as well as on field in Hungary and Slovenia. We are proud on our collaboration and want to congratulate Nataša.
Ákos and Jelena together with dr Desanka Kostić and dr Nebojša Andrić were members of the defense committee, while dr Željko Popović was the supervisor.

Nataša during defense
Nataša during defense
Nataša during defense
Committee members (from the left: Željko Popović, Nebojša Andrić, Desanka Kostić, Ákos Horváth and Jelena Lujić)
Nataša with committee members

Visit of our colleague from FYR Macedonia

From May 5th and 12th we hosted dr Dijana Blažeković Dimovska from the Biotechnical Faculty (Bitola University, FYR Macedonia) at our Department. She was the guest of our team and had opportunity to work in our laboratories for one week. Dijana jond us for sperm and gonad cryopreservation experiments as well as for germ cell viability tests. It was our pleasure to host Dijana, and we are looking forward to seeing her again in the near future. 

Fish dissection with Ilija
Germ cell viability test
Hormonal induction of carp
Hormonal induction of carp
Dijana with our group
Dijana with our group


New paper accepted in Fish Physiology and Biochemistry

A new paper in collaboration with our colleagues from the Angling Club of Tolmin (Slovenia) was accepted for publication in the journal `Fish Physiology and Biochemistry`.

Kása E., Lujić J., Marinović Z., Kollár T., Bernáth G., Bokor Z., Urbányi B., Lefler K., K., Jesenšek D., Horváth Á. 2018. Development of sperm vitrification protocols for two endangered salmonid species: the Adriatic grayling, Thymallus thymallus and the Marble trout, Salmo marmoratus. Fish Physiology and Biochemistry.

Vitrification was successfully applied to the sperm of two endangered fish species of Soča river basin in Slovenia, the Adriatic grayling (Thymallus thymallus) and marble trout (Salmo marmoratus). Sperm was collected, diluted in species-specific nonactivating media containing cryoprotectants and vitrified by plunging directly into liquid nitrogen without pre-cooling in its vapor. Progressive motility, curvilinear velocity and straightness of fresh and vitrified-warmed sperm were evaluated with computerassisted sperm analysis (CASA). Fertilization trials were carried out to test the effectiveness of vitrification in the case of grayling. A protocol utilizing a glucose-based extender, 30% cryoprotectants (15 % methanol + 15 % propylene glycol), 1:1 dilution ratio and droplets of 2 μl on a Cryotop as cooling device yielded the highest post-thaw motility values for both Adriatic grayling (7.5 ± 6.5%) and marble trout (26.6 ± 15.8%). Viable embryos were produced by fertilizing eggs with vitrified grayling sperm (hatch after vitrification/warming: 13.1±11.7%, control hatch: 73.9±10.4%). The vitrification protocol developed in this study can be utilized in the conservation efforts for the two species as an alternative to slow-rate freezing when working in field conditions or when specific equipment necessary for slow-rate freezing is not available.


New paper accepted in Fish Physiology and Biochemistry

A new paper in collaboration with our colleagues from University of Ljubljana, Slovenia, was accepted for publication in the journal `Fish Physiology and Biochemistry`.

Lujić J.,Marinović Z., Sušnik Bajec S., Djurdjevič I., Urbányi B., Horváth Á. 2018. Interspecific germ cell transplantation: A new light in the conservation of valuable Balkan trout genetic resources? Fish Physiology and Biochemistry

Abstract: Interspecific transplantation of germ cells from the brown trout Salmo trutta m. fario and the European grayling Thymallus thymallus into rainbow trout Oncorhychus mykiss recipients was carried out in order to improve current practices in conservation of genetic resources of endangered salmonid species in the Balkan Peninsula. Current conservation methods mainly include in situ efforts such as the maintenance of purebred individuals in isolated streams and restocking with purebred fingerlings, however additional ex situ strategies such as surrogate production are needed. Steps required for transplantation such as isolation of high number of viable germ cells and fluorescent labeling of germ cells which are to be transplanted have been optimized. Isolated and labelled brown trout and grayling germ cells were intraperitoneally transplanted into three to five days post hatch rainbow trout larvae. Survival of the injected larvae was comparable to the controls. Sixty days after transplantation,fluorescently labelled donor cells were detected within the recipient gonads indicating successful incorporation of germ cells (brown trout spermatogonia and oogonia - 27%; grayling spermatogonia - 28%; grayling oogonia - 23%). PCR amplification of donor mtDNA CR fragments within the recipient gonads additionally corroborated the success of incorporation. Overall, the transplantation method demonstrated in this study presents the first step and a possible onset of the application of the germ cell ransplantation technology in conservation and revitalization of genetic resources of endangered and endemic species or pop ulations of salmonid fish and thus give rise to new or improved management strategies for such species.


New paper accepted in Science of the Total Environment

A new paper in collaboration with our colleagues from University of Novi Sad, Serbia (Department of Biology and Ecology, Faculty of Science) was accepted for publication in Science of the Total Environment. It was long and complex, but finally successful scientific mission. We would  like to thank to all coauthors, but especially to dr Nada Tokodi and dr Damjana Drobac for all their effort. 

Tokodi N., Drobac D., Meriluoto J., Lujić J., Marinović Z., Važić T., Nybom S., Simeunović J., Dulić T., Lazić G., Petrović T., Vuković-Gačić B., Sunjog K., Klarević S., Kračun-Kolarević M., Subakov-Simić G., Miljanović B., Codd G.A., Svirčev Z. 2018. Cyanobacterial effects in Lake Ludoš, Serbia - is preservation of a degraded aquatic ecosystem justified? Science of the Total Environment

Abstract - Cyanobacteria are present in many aquatic ecosystems 51 in Serbia. Lake Ludoš, a wetland area of international significance and an important habitat for waterbirds, has become the subject of intense research interest because of practically continuous blooming of cyanobacteria. Analyses of water samples indicated a deterioration of ecological condition and water quality, and the presence of toxin-producing cyanobacteria (the most abundant Limnothrix redekei, Pseudanabaena limnetica, Planktothrix agardhii and Microcystis spp.). Furthermore, microcystins were detected in plants and animals from the lake: in macrophyte rhizomes (Phragmites communis, Typha latifolia and Nymphaea elegans), and in the muscle, intestines, kidneys, gonads and gills of fish (Carassius gibelio). Moreover, histopathological deleterious effects (liver, kidney, gills and intestines) and DNA damage (liver and gills) were observed in fish. A potential treatment for the reduction of cyanobacterial populations employing hydrogen peroxide was tested during this study. The treatment was not effective in laboratory tests although further in-lake trials are needed to make final conclusions about the applicability of the method. Based on our observations of the cyanobacterial populations and cyanotoxins in the water and other aquatic organisms and, a survey of historical data on Lake Ludoš, it can be concluded that the lake is continuously in a poor ecological state. Conservation of the lake in order to protect the waterbirds (without urgent control of eutrophication) actually endangers them and the rest of the biota in this wetland habitat, and possibly other ecosystems. Thus, urgent measures for restoration are required, so that the preservation of this Ramsar site would be meaningful.


3rd Conference of Young Biotechnologists, 28-29. March 2018

Timi, Eszti, Betti (our new collegue) and Dóri (master student of our group) have participated at the 3rd Conference of Young Biotechnologists organized at Eötvös Loránd University in Budapest.

  • Bernadett PATAKI, Csilla PELYHE, Erika ZÁNDOKI, Miklós MÉZES, Krisztián BALOGH. SHORT-TERM EFFECTS OF DON AND T-2 TOXIN CONTAMINATED FEED ON CARP JUVENILES. Conference of Young Biotechnologists, 28-29. March 2018 Book of Abstracts p. 14.
  • Dóra SZERÉNYI, Jelena LUJIĆ, Ákos HORVÁTH, Zoran MARINOVIĆ. SLOW COOLING AND VITRIFICATION OF EUROPIAN CATFISH (SILURUS GLANIS) TESTICULAR TISSUE.  Conference of Young Biotechnologists, 28-29. March 2018 Book of Abstracts p. 22.
  • Eszter KÁSA, Tímea KOLLÁR, Jelena LUJIĆ, Zoran MARINOVIĆ, Béla URBÁNYI, Ákos HORVÁTH. VITRIFICATION OF ZEBRAFISH (DANIO RERIO) GERM CELLS FOR GENE CONSERVATION PURPOSES. Conference of Young Biotechnologists, 28-29. March 2018 Book of Abstracts p. 69.

Timi, Eszti, Betti and Dóri
Dóri with her poster
Timi with her poster
Eszti with her poster
Betti during her presentation
Betti answering the questions of the audiance
Dóri during her presentation


HU-SRB Bilateral project "Invasive and blooming cyanobacteria in Serbian and Hungarian waters - a threat to fish?"

From March 14th until 17th, Eszti, Jelena and Ilija Šćekić (Master student in our group) were in Serbia as a part of our HU-SRB Bilateral project "Invasive and blooming cyanobacteria in Serbian and Hungarian waters - a threat to fish?".
In this project, we collaborate with our dear colleagues from the University of Novi Sad lead by prof. dr Zorica Svirčev. During their stay, they were hosted by colleagues from the Laboratory for Paleoenvironmental Research (LAPER) and Laboratory for Hydrobiology, Department of Biology and Ecology, Faculty of Sciences, Novi Sad.
Our team had opportunity to visit Novi Sad Cyanobacterial Culture Collection (NSCCC) and Chamber for experimental research of BLOCDUST hypothesis that are part of LAPER long-term projects at the Department in Novi Sad.
The main goal of the visit was fieldwork and the first sampling of water, phytoplankton and fish on the Special Nature Reserve "Ludaš" for this year. Various fish tissues were collected for further histological analysis and examination of possible effects of continued water blooming that occurs in that lake.
After the successful field work, we got invitation to visit Palić Zoo where we were guests of Kristian Ovari, the main biologist at the Zoo. We spent nice time there in a friendly atmosphere; thank you Kristian.
We would also like to thank our hosts, especially dr Nada Tokodi, dr Damjana Drobac, Sándor Sipos and Nemanja Pankov for perfect organization, joint work and valuable support and help on the field.

Nemanja measuring physical-chemical parameters of the water
Nemanja taking water samples
Nemanja collecting phytoplankton
It is time for fish sampling
Sándor and Nemanja are ready...
...and go

Tissue collecting
Tissue collecting
Tissue collecting
Samples are ready
Chamber for experimental research of BLOCDUST hypothesis
Visit to the Department of Biology and Ecology with dr Desanka Kostić, dr Damjana Drobac and dr Nada Tokodi
Novi Sad Cyanobacterial Culture Collection (NSCCC)
Novi Sad Cyanobacterial Culture Collection (NSCCC)
Visit to Palić Zoo with our dear host Krstijan Ovari
Palić Zoo
Palić Zoo