Maria Ogielska

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Verified

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• PhD
• Professor Emeritus at University of Wrocław

The gonads of amphibians, like other vertebrates, consist of somatic tissues, which create a specific environment essential for the differentiation of germline cells. The earliest stages of gametogenesis still remain underexplored in anuran amphibians. We propose to introduce the term “pregametogenesis” for a specific period of gonocyte proliferati...

Two water frog species: the pool frog Pelophylax lessonae (L) and the marsh frog P. ridibundus (R) occur sympatrically in Central Europe and form mixed populations (genetic systems) with their hybrid, the edible frog P. esculentus (E). The aim of the study was to assess the species composition of water frogs in urban and rural populations and compa...

Hybrid taxa from the genus Pelophylax can propagate themselves in a modified way of sexual reproduction called hybridogenesis ensuring the formation of clonal gametes containing the genome of only one parental (host) species. Pelophylax grafi from South-Western Europe is a hybrid composed of P. ridibundus and P. perezi genomes and it lives with a h...

Central European water frog Pelophylax esculentus is a hybrid that lives sympatrically and forms genetic systems with one of its parental species, in this case L-E (P. lessonae - P. esculentus). Hybrids are restored in each generation due to hybridogenesis, a unique mode of hemiclonal reproduction. We investigated changes in the species composition...

Hybridogenesis is a hemiclonal reproductive strategy in diploid and triploid hybrids. Our study model is a frog P. esculentus (diploid RL and triploids RLL and RRL), a natural hybrid between P. lessonae (LL) and P. ridibundus (RR). Hybridogenesis relies on elimination of one genome (L or R) from gonocytes (G) in tadpole gonads during prespermatogen...

An intriguing outcome of hybridisation is the emergence of clonally and hemiclonally reproducing hybrids, that can sustain, reproduce, and lead to the emergence of polyploid forms. However, the maintenance of diploid and polyploid hybrid complexes in natural populations remains unresolved. We selected water frogs from the Pelophylax esculentus comp...

Abstract Under incomplete reproductive isolation, secondary contact of diverged allopatric lineages may lead to the formation of hybrid zones that allow to study recombinants over several generations as excellent systems of genomic interactions resulting from the evolutionary forces acting on certain genes and phenotypes. Hybrid phenotypes may eith...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

In most organisms, cells typically maintain genome integrity, as radical genome reorganization leads to dramatic consequences. However, certain organisms, ranging from unicellular ciliates to vertebrates, are able to selectively eliminate specific parts of their genome during certain stages of development. Moreover, partial or complete elimination...

The fire salamander Salamandra salamandra is a widespread taxon in Europe, exhibiting great intraspecific diversity in phenotype and life history traits across its geographical distribution. Here, we studied body size, sexual dimorphism, age, growth rate and condition of fire salamanders from the north-eastern margin of its range. In total, 2,102 i...

Using a recently developed approach for testing endocrine disruptive chemicals (EDCs) in amphibians, comprising synchronized tadpole exposure plus genetic and histological sexing of metamorphs in a flow-through-system, we tested the effects of 17β-Trenbolone (Tb), a widely used growth promoter in cattle farming, in three deeply diverged anuran fami...

Little is known about amphibian feeding activity during post-hibernation migration to breeding ponds. It is widely assumed that explosively breeding anurans do not feed between the end of hibernation and completion of breeding. We investigated the potential for using road-killed common toads Bufo bufo in order to find out whether migrating toads fe...

The Hyrcanian Forests present a unique Tertiary relict ecosystem, covering the northern Elburz and Talysh Ranges (Iran, Azerbaijan), a poorly investigated, unique biodiversity hotspot with many cryptic species. Since the 1970s, two nominal species of Urodela, Hynobiidae, Batrachuperus (later: Paradactylodon) have been described: Paradactylodon pers...

DNA elimination is a radical form of gene silencing and occurs both in somatic and germ cells. The programmed DNA elimination occurs during gametogenesis in interspecies hybrids that reproduce by hybridogenesis (stick insects, fishes, and amphibians) and concerns removal of whole genomes of one of the parental species and production of clonal gamet...

We analysed variation of dorsal yellow patterns in 2077 individuals that represented 23 populations from the northern parts of the Sudetes and the Carpathian Mountains. We distinguished four types of yellow patterns: spotted (50.1%), spotted-and-striped (42.8%), zig-zag (5.8%), and striped (1.3%). Spotted form dominated in the east (69.2%, the Carp...

Spermatogenesis in amphibians occurs inside spermatogenic cysts formed by Sertoli cells (SCs). SCs do not constitute a permanent population and their number increases during spermatogenic cycle and ontogeny. The number of SCs per cyst is strongly correlated with the number of germ cells in the same cyst and with the cyst volume. The number of germ...

Celem badań było określenie składu gatunkowego płazów występujących w stawie przy ul. Pautscha we Wrocławiu w 2015 roku, porównanie wyników z danymi pochodzącymi z monitoringu prowadzonego od roku 1993 oraz wykazanie aktualnych zagrożeń mogących oddziaływać na siedlisko płazów, w tym zanieczyszczeń metalami ciężkimi. stwierdzono obecność czterech t...

Recent molecular studies have detected the occurrence of exotic water frog species (Pelophylax sp.) in central and western European populations. Here, we report genetic evidence for the occurrence of the Balkan water frog, Pelophylax kurtmuelleri, in southwestern Poland. We found a high frequency of an allele of serum albumin intron-1 and a mitocho...

The fungus Batrachochytrium dendrobatidis (Bd) is a pathogen associated with global declines of amphibians. We used qPCR to detect Bd in 255 samples from 10 Polish populations of 8 species. We found Bd infection in 3 species (Bombina variegata, Pelophylax lessonae, P. esculentus). The infection intensity in P. lessonae reached a maximum of 58 400 g...

We studied water frogs from a complex composed of two species: Pelophylax lessonae (Camerano, 1882) (genome LL, 2n = 26) and P. Ridibundus (Pallas, 1771) (RR, 2 = 26), and their natural hybrid P. Esculentus (Fitzinger, 1843) of various ploidy and genome composition (RL, 2n = 26, and RRL or RLL, 3n = 39). Tetraploids RRLL were found (4n = 52) in juv...

Three species of water frogs (Pelophylax esculentus complex) inhabit the territory of Latvia. Using PCR method the species affiliation was performed for 50 frogs from 5 water bodies. P. ridibundus was found in two sites: the Kish and the Jugla Lakes in Riga city. P. esculentus was identified in four habitats: the Jugla Lake in Riga city, small pond...

Pelophylax esculentus is the fertile hybrid of P. ridibundus and P. lessonae. During gametogenesis, one of the parental genomes is removed from the germ line cells, whereas the other one is clonally transmitted to the gametes. In hybrids, development of gonads is delayed in comparison with parental species. This may result from complex processes of...

Spermatogenesis in frogs was for the first time divided into two phases: prespermatogenesis, when gonocytes proliferate in developing tadpole testes, and active spermatogenesis when spermatogonial stem cells (i.e. descendants of gonocytes), either self-renew or enter into meiotic cycles within cysts formed by Sertoli cells. We argue that amphibian...

Ultrasound imaging has more frequently been used in veterinary medicine of amphibians and reptiles. In this study, we have verified the usefulness of ultrasound imaging in pregnancy determination of the fire salamander Salamandra salamandra. We have also undertaken to estimate the number of larvae and their developmental stage directly in the ovidu...

Due to their terrestrial habitats and aquatic reproduction, many amphibians are both very vulnerable and highly suitable bioindicators. The plasticizer bisphenol A (BPA) is one of the most produced chemical substances worldwide, and knowledge on its impacts on humans and animals is mounting. BPA is used for the industrial production of polycarbonat...

Amphibians are undergoing a global decline. One poorly investigated reason could be the pollution of aquatic habitats by endocrine disrupting compounds (EDCs). We tested the susceptibility to the synthetically stabilized estrogen 17α-ethinylestradiol (EE2) in three deeply diverged anuran species, differing in sex determination systems, types of gon...

Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility...

Reproductive isolation is crucial for the process of speciation to progress. Sex chromosomes have been assigned a key role in driving reproductive isolation but empirical evidence from natural population processes has been restricted to organisms with degenerated sex chromosomes such as mammals and birds. Here we report restricted introgression at...

Pelophylax esculentus is the fertile hybrid of P. ridibundus and P. lessonae. During gametogenesis one of the parental genomes is removed from the germ line cells, whereas the second one is clonally transmitted to the gametes. The development of ovaries is divided into ten stages. In hybrids, the maturation of the gonads is delayed in comparison to...

Amphibian populations occurring at the margin of the species range exhibit lower genetic variation due to strong genetic drift and long-term isolation. Limited mobility and site fidelity together with habitat changes may accelerate genetic processes leading to local extinction. Here, we analyze genetic variation of the fire salamander subspecies Sa...

Due to the prevailing sex chromosome homomorphy and large genome size, the knowledge on sex determination systems, sex chromosomes and sex-determining genes in amphibians remains scarce. Using 3 cross-amplifying sex-linked microsatellite markers, we uncover sex determination systems and sex chromosomes in purebred, diploid Palearctic green toads (B...

Occasional XY recombination is a proposed explanation for the sex-chromosome homomorphy in European tree frogs. Numerous laboratory crosses, however, failed to detect any event of male recombination, and a detailed survey of NW-European Hyla arborea populations identified male-specific alleles at sex-linked loci, pointing to the absence of XY recom...

Contrasting with the situation found in birds and mammals, sex chromosomes are generally homomorphic in poikilothermic vertebrates. This homomorphy was recently shown to result from occasional X-Y recombinations (not from turnovers) in several European species of tree frogs (Hyla arborea, H. intermedia and H. molleri). Because of recombination, how...

Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a...

We describe a pentaploid froglet (LLLRR; three Pelophylax lessonaeand two Pelophylax ridibundusgenomes) that has never been reported before within the Water Frog Pelophylax esculentus)hybrid complexes. The pentaploid specimen was found among almost all triploid siblings obtained from a diploid femaleP. esculentus(LR) crossed with a diploid male P....

Testis differentiation in anuran amphibians is the result of two opposing processes: degeneration of the distal part, and development of the proximal part, which becomes a functional male gonad. Undifferentiated gonad differentiates directly into a testis without a transition phase. We described the morphology of developing testes in Rana temporari...

Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a...

There are three taxons of central European water frogs of the Pelophylax esculentus complex: two morphologically distinct species, Pelophylax lessonae (LL) and Pelophylax ridibundus (RR), and hybrids Pelophylax esculentus, which can be either diploid (RL) or triploid (LLR or RRL). The morphology of hybrids is supposed to follow genome dosage effect...

Western Palearctic water frogs in the genus Pelophylax are a set of morphologically similar anuran species that form hybridogenetic complexes. Fully reliable identification of species and especially of hybrid ploidy depends on karyological and molecular methods. In central Europe, native water frog populations consist of the Pelophylax esculentus c...

Parasitic fauna of water frogs was mainly studied in the second half of the 20th century. However, these studies were done without differentiation into species and hybrids and pooled the 3 taxa as “water frogs” or “green frogs”. The aim of this study was to make an inventory of helminth species as well as their prevalence and intensity of infection...

The Western Palearctic water frogs Pelophylax ridibundus and P. lessonae were identified as parental (sexual) species and P. esculentus as their interspecific, hybridogenetically reproducing hybrid with hemiclonal heredity. We used genomic in situ hybridization (GISH) to identify parental chromosomes of P.lessonae and P.ridibundus in diploid P. esc...

Central European water frog Pelophylax esculentus (formerly known as Rana esculenta) is a natural hybrid between P. lessonae and P. ridibundus. The hybrids reproduce by hybridogenesis and usually share populations with one of the parental species. Natural ridibundus-esculentus (R-E) mixed populations are rare. The population described herein is com...

Obszarami nadal bogatymi w populacje salamandry plamistej są Park Krajobrazowy „Chełmy” i okolice Jawora, Góry Suche i okolice Nowej Rudy oraz Góry Bardzkie i okolice Kłodzka. Zgrupowania 2-3 sąsiadujących ze sobą populacji znajdują się w Karkonoszach, Parku Krajobrazowym „Doliny Bobru” i Rudawach Janowickich. Populacje salamander występujące na po...

The paper presents information about the amphibian species in Wroclaw – frequency oftheir occurrence as well as number of individuals in water bodies. For the study 31 sites were selected. Only in two sites no amphibians were found. On the rest of the sites in total 11 amphibian taxons were present – Triturus cristatus, Triturus vulgaris, Bombina b...

Ogielska, M., Rozenblut, B., Augustyńska, R., Kotusz, A. 2010. Degeneration of germ line cells in amphibian ovary. —Acta Zoologica (Stockholm) 91: 319–327 We studied the morphology of degenerating ovarian follicles in juvenile and adult frogs Rana temporaria, Rana lessonae and Rana ridibunda. Degeneration of primordial germ cells was never observed...

Background: Hybridogenesis is a very interesting example of reproduction which seems to integrate the sexual and clonal processes in one system. In a case of frogs, described in the paper, two parental species - Rana lessonae and Rana ridibunda can form fertile hybrid individuals - Rana esculenta. Hybrid individuals eliminate one parental haplotype...

The Eastern Mediterranean contains several important biogeographic sub-regions and major Pleistocene refugia. Greece is a meeting zone of faunal elements of Asia Minor and of Balkan Peninsular origin. Within two ongoing projects, we analyze mitochondrial sequences from green toads (Bufo viridis subgroup; mtDNA D-loop) and tree frogs (Hyla arborea g...

Rana esculenta is a hybridogenetic hybrid between Rana ridibunda and Rana lessonae. Usually the hybrids, among which diploid and triploid individuals of both sexes were described, live in mixed populations with one of the parental species (L-E or R-E systems). The hybrids also form pure esculenta-esculenta populations (E-E system). 114 individuals...

Differentiation and development of long bones were studied in European water frogs: Rana lessonae, R. ridibunda, and R. esculenta. The study included premetamorphic larvae (Gosner Stage 40) to frogs that were 5 years old. Femora, metatarsal bones, and proximal phalanges of the hindlimb exhibit the same pattern of periosteal bone differentiation and...

The Central European water frog Rana esculenta L., 1758 is a natural hybrid between Rana lessonae Camerano, 1882 (LL) and Rana ridibunda Pallas, 1771 (RR). Hybrids are usually diploid (RL) or triploid (LLR or RRL). Distinguishing LL from RL, RR from RL, and LLR from RRL according to external morphology is ambiguous. In this study we checked whether...

The rate of somatic development of anuran amphibians is only roughly correlated with the rate of gonad differentiation and varies among species. The somatic stage of a tadpole often does not reflect its age, which seems to be crucial for gonad differentiation rate. We compared the morphology and differentiation of developing ovaries at the light an...

European water frog, Rana esculenta, is a hybrid whose genome is composed of haploid sets of its parental species: R. lessonae and R. ridibunda. Before meiosis one of the parental sets is discarded and the other one is reduplicated. So far, the mode of rejection has been described during oogenesis. It takes place at tadpole stages during the prolon...

One species of brown frog (Rana temporaria) and two species of green frogs (R. lessonae and R. ridibunda) were studied. R. temporaria is a species whose breeding season takes place in early spring (March/April), while R. lessonae and R. ridibunda breed in the middle of May. The stages of tadpole development were established according to Gosner (196...

Bibliogr. s. 34-39. - Angl. souhrn

A female Rana kl. esculenta was crossed with three different R. lessonae males. Three froglets with unexpected phenotypes appeared. Two of them were chimerae with one side of the body of lessonae, and the other of escutenta phenotype, and one displayed lessonae, instead of the expected esculenta, phenotype. Blood of three individuals was composed o...

Numerous intramitochondrial paracrystalline inclusion bodies (ICIB) were observed in the germinal plasm of a mid-blastula, and in primordial germ cells (PGCs) after their migration to the germinal ridges, in Rana ridibunda, R. lessonae and R. esculenta. In oogonia the number of ICIB decreases rapidly. Single ICIB are observed in the germ cells up t...