Yu. M. Rozanov

• Senior Researcher at Russian Academy of Sciences

Many closely related species are capable of mating to produce hybrid offspring, which are usually sterile. Nevertheless, altering the gametogenesis of hybrid offspring can rescue hybrids from sterility by enabling asexual reproduction. Hybridogenesis is one of the most complicated asexual reproductive modes, and it includes drastic genome reorganiz...

Background. Being an interesting case of unusual reticulate evolution at the species level, polyploid speciation in Asian green toads of the genus Bufotes draws an attention of many researchers. The aim of the paper was to determine a sequence of events that could lead to origin of polyploid species in the genus. Materials and methods. Two diploid...

Background Interspecies animal hybrids can employ clonal or hemiclonal reproduction modes where one or all parental genomes are transmitted to the progeny without recombination. Nevertheless, some interspecies hybrids retain strong connection with the parental species needed for successful reproduction. Appearance of polyploid hybrid animals may pl...

Th is article examines polyploidy in amphibians. 53 polyploid species from 15 genera and 10 families (only anurans) are currently recognized. Th ey can be arranged in 4 groups with diff erent ploidy levels: I (triploids), 4 species of the toad genus Bufotes, II (tetraploids), 33 species from 14 genera and 10 families, III (octoploids), 12 species f...

Since the pioneering proposal of the replicon model of DNA replication 50 years ago, the predicted replicons have not been identified and quantified at the cellular level. Here, we combine conventional and super-resolution microscopy of replication sites in live and fixed cells with computational image analysis. We complement these data with genome...

Supplementary Figures 1-7, Supplementary Table 1, Supplementary Notes 1-4 and Supplementary References

Time-lapse confocal microscopy of dividing HeLa Kyoto cells expressing GFP-PCNA. Scale bar: 30 micron.

Time-lapse 3D-SIM microscopy of replicating C2C12 cells expressing GFP-PCNA. Scale bar: 5 micron.

A triploid specimen of the diploid anuran species Bombina orientalis was identified by means of DNA flow cytometry. The finding is interpreted as a case of natural spontaneous autotriploidy. The incidence of triploidy was 1.8% per species (n = 55) and 11.1% per sample (n = 9).

Two triploid individuals of diploid green frog species Pelophylax cerigensis and P. cretensis were recorded in Rhodes and Crete islands (Greece). Triploidy was identified by means of DNA flow cytometry. The cases are recognized as a natural spontaneous autotriploidy. In P. cretensis incidence of triploidy was 10.0% per sample and 6.7% per species,...

The genome size of the Chinese hamster Cricetulus griseus, absolute and relative DNA content of individual chromosomes in normal Chinese hamster karyotype and Chinese hamster cell lines V-79 RJK and Vebr-5 during long-term cultivation were determined with flow cytometry and microfluorimetry. It has been shown that the genome size of Chinese hamster...

Using cytometry and an microfluorimetry, we have determined the genome size in Chinese hamster Cricetulus griseus, as well as absolute and relative DNA content of its individual chromosomes and of chromosomes in the transformed Chinese hamster cell lines V-79 RJK and Vebr-5 after prolonged cultivation. It has been shown that the genome size in male...

Incompatibilities between parental genomes decrease viability of interspecific hybrids; however , deviations from canonical gametogenesis such as genome endoreplication and elimination can rescue hybrid organisms. To evaluate frequency and regularity of genome elimination and endoreplication during gametogenesis in hybrid animals with different plo...

The occurrence of three green frog taxa (Pelophylax lessonae, P. ridibundus, and P. esculentus) in Kaliningrad oblast’ of Russia was evidenced by DNA flow cytometry analysis. Almost all frogs were diploid. Only one young specimen of P. esculentus proved to be a triploid with two genomes of P. ridibundus and one genome of P. lessonae. The triploidy...

Molecular-genetic analysis of green frogs (67 individuals of Pelophylax ridibundus and 63 ones of hybridogenic P. esculentus) from Mari El Republic (15 localities) and the Kirov Region (one locality) was performed by two (mitochondrial and nuclear) markers. Some part of the material (66 individuals) was studied by means of DNA flow cytometry. It is...

Mass hindlimb abnormalities (above 60 %) were found in two localities with syntopic Pelophylax ridibundus and hybridogenous P. esculentus in Pridnestrovie. Individually, frogs can have 1–7 anomalies in P. ridibundus and 2–4 in P. esculentus. Some differences in variety of deformities and their frequencies were observed between both species and both...

Based on allozyme variation of 410 newly collected individuals from 52 localities, we reconstructed range-wide phylogeography of the widespreadWestern Palearctic anuran, Pelobates fuscus. To study genetic diversity, evolutionary history, postglacial range expansion and secondary contact zones, we used a multidisciplinary approach combining informat...

A microfluorimetric method has been developed for determination of DNA content in individual human chromosomes. The method is based on a preliminary identification of chromosomes with Hoechst 33258 followed by staining of the chromosomes with Feulgen reaction by using Schiff’s reagent type ethidium bromide-SO2 and then by measuring the fluorescence...

Background Hybridogenesis (hemiclonal inheritance) is a kind of clonal reproduction in which hybrids between parental species are reproduced by crossing with one of the parental species. European water frogs (Pelophylax esculentus complex) represent an appropriate model for studying interspecies hybridization, processes of hemiclonal inheritance an...

Hybridogenesis represents one of known clonal ways by which interspecies hybrids can be reproduced. During hybridogenesis, gametogenesis proceeds with deviations, when one of the parental genomes can be eliminated while the other one can be endoreduplicated. Among natural interspecies hybrids, Pelophylax esculentus as a hybrid between P. ridibundus...

Three species of green frogs were identified in Mari El Republic by means of the DNA flow cytometry analysis, namely: the marsh or lake frog, Pelophylax ridibundus (Pallas, 1771), the pool frog, P. lessonae (Camerano, 1882), and the edible frog, P. esculentus (Linnaeus, 1758). The last species (of hybrid origin) was reliably recorded in this territ...

A triploid female of diploid toad species Bufo raddei was recorded in Buryatia Republic, Eastern Siberia, Russia. Triploidy was identified by means of DNA flow cytometry. The case is recognized as an occasional autotriploidy. No morphological difference was found between triploid and diploid females of the sample.

The effect of the metabolic drug Cytoflavin (CF) with antihypoxic and antioxidative properties on human dermal fibroblasts in the model of ischemia/reoxygenation in vitro was studied. It was revealed that, during the reoxygenation period after ischemia, the cell death rate in culture with CF appeared to be 2–2.7 times lower than in control cultures...

The records of bisexual all-triploid populations of B. baturae in the southern Pamir (Tajikistan) and B. zamdaensis in the Spiti River valley (India) are described. Genome size, karyotypes, 16S rRNA sequences and allozyme variation are studied. Taxonomic status, genetic reproductive pattern and distribution of the toads are discussed.

We studied the distribution of Palearctic green toads (Bufo viridis subgroup), an anuran species group with three ploidy levels, inhabiting the Central Asian Amudarya River drainage. Various approaches (one-way, multivariate, components variance analyses and maximum entropy modelling) were used to estimate the effect of altitude, precipitation, tem...

p130/E2f4 suppressor complex inhibits the transcription of multiple genes that regulate the cell cycle and induces cell cycle arrest at G0/G1. This is a requirement for the initiation of cell differentiation in many tissues. Here, we found that the activation of the Wnt/β-catenin signaling in mesenchymal stem cells (MSC) induced by their coculture...

Seven types of population systems of green frogs are found on Russian Plain' territory. «Pure» populations of R. ridibunda (R-type), apart from zone of allopatric distribution in the south-east of region, are frequently occurred in the zone of sympatry, in water bodies of open landscapes. «Pure» populations of R. lessonae (R-type) predominate in th...

Morphological and molecular-genetic characteristics of newts of the Lissotriton vulgaris complex were analyzed. Signifi cant taxonomic differences between both species and subspecies were revealed. Species rank of the Caucasian L. v. lantzi is suggested. Based on molecular and paleogeographic data, our scenario involves ancient origin of the group...

Based on flow DNA cytometry and morphological method, we identified three species of green frogs (R. esculenta, R. ridibunda, and R. lessonae) in the Psyol' River Drainage in Russia (Kursk Province, Oboyan and Belaya districts) and Ukraine (Poltava Province, Gadyach District). The species composed four kinds of mixed population systems (REL, RE, LE...

This work studies the mechanisms of dysdifferentiation at cell neoplastic transformation based on the example of heterogeneity of the cell populations that form malignant tumors. Two natural fractions of Zajdela rat hepatoma cells are revealed that differ in the type of growth in the primary culture. Cells of one fraction are attached to substrate...

Tetraploid green toad, Bufo pewzowi Bedriaga, 1898 was found in Altay Republic. This is the first record of the species for Siberia and Russia in general. The distribution of diploid and tetraploid toads in Siberia and adjacent territories of eastern Kazakhstan and north-western China is outlined. Bufo pewzowi is recommended to list in the Red Data...

This work is devoted to the study of molecular and cellular mechanisms of disdifferentiation during neoplastic transformation of cells by investigating the malignant tumor cell heterogeneity. We have revealed two cell fractions of hepatoma Zajdela which differ in patterns of growth in primary culture. The cells of one fraction were attached to the...

The genome size in 389 specimens from 97 samples of B. bufo, B. eichwaldi, B. gargarizans and B. verrucosissimus was studied.

The habitat distribution of three species of the Rana esculenta complex is considered. Rana ridibunda was recorded in water bodies of various size, origin, and character. However, the species avoids small water bodies situated deeply in a forest. In forest landscapes, the lake frog inhabits ponds, sand pits, and other water bodies. In contrast, R....

Based on flow DNA cytometry, we identified three species of green frogs (R. esculenta of hybrid origin, as well as all parental species R. ridibunda, and R. lessonae) in Dnepropetrovsk Province (villages Bulakhovka and Kocherezhki, Pavlograd District). Our records moved the southern distributional border of R. esculenta and R. lessonae in 120 km. T...

The variability and the taxonomic relationships of the Common or Grey Toads of the Eastern Europe, Western Siberia, Transcaucasians, including the North Caucasus and the Far East are studied, the 589 of animals from the 73 localities altogether. The analysis of external morphology, skeleton, chromosomal complements, the nuclear DNA content and enzi...

The study of the antigen diversion of cells of rat hepatocellular tumors, which is caused by the expression of normal antigens peculiar to renal definitive tissues (so-called “heteroorganic renal antigens”) is continued. Using an immune serum of narrow specificity, in the plasma membrane fractions of Zajdela ascites hepatoma cells and of cultivated...

Ouabain-sensitive (OS) and -resistant (OR) Rb(+) influx was examined in three sublines of U937 cells to compare alterations of K(+) channel permeability and the Na(+),K(+)-ATPase pump leading to the shift in ion and water balance during apoptosis induced by 0.2 and 1microM staurosporine (STS) for 4-5 h. Cell K(+), Rb(+), Na(+) and Cl(-) content was...

The genome size, protein (24 loci) and morphological variation in three currently recognized species of the Bufo bufo group was studied. Among common toads of the Caucasian Isthmus, two distinct groups were revealed. The main territory of the Caucasian region, including the Great Caucasian Range and the Caucasus Minor, is inhab-ited by the Caucasia...

The genome size and genetic (allozymes, microsatellites, and mitochondrial DNA) variation was studied in fi ve families of anurans from the territory of Russia and some adjacent countries (6977 specimens of 32 species). Based on genome size, we found clear geographic groups in the majority of wide-ranging species of the genera Bombina, Pelobates, B...

Lissotriton vulgaris and L. montandoni from the L. vulgaris group well differ by al-lozymes and morphological characters. Genetic data demonstrated the most distant position of L. v. lantzi among subspecies of L. vulgaris. Based on allozymes, two Turkish subspecies L. v. kosswigi и L. v. schmidtlerorum were closely related, while they well differed...

We used flow cytometry to measure the nuclear DNA content in erythrocytes of 27 salamandrid species. Across these species, diploid genome size varied more than 2 fold (51.3-104.4 pg). According to genome size and geographic distribution, 3 groups of newt species were recognized: West Palearctics with smaller amounts of nuclear DNA; Nearctic, with i...

Heat resistance of the gastrocnemius muscle was studied in five species of the Rana esculenta complex. It was similar in R. bedriagae, R. lessonae, and in the European form of R. ridibunda; while North African R. saharica demonstrated a lower heat resistance. No heterosis was expressed in R. esculenta, a clonal hybrid of R. lessonae and R. ridibund...

A triploid female (3n = 33) was found in diploid species Bufo viridis from the Crimea Peninsula, Ukraine. The case is recognized as an occasional autotriploidy. No morphological differences were found between this triploid female and other diploid specimens of the sample. Three categories of triploids in the Bufo viridis group are clas-sified. Base...

The variability of microsatellites BM224 and Bcal7 was studied for the first time in three species of the diploid-polyploid complex of Bufo viridis (B. viridis, B. oblongus, and B. pewzowi). The locus Bcal7 was established to be monomorphic in all samples studied. In microsatellite BM224, three allele variants were found. Among tetraploid toads, th...

The genome size and allozyme (20 loci) variation in the European (Hyla arborea) and Middle Eastern (H. sa-vignyi) tree frogs in the Caucasus was studied. Additional samples of these species from eastern Europe and Tur-key, as well as a sample of the Far Eastern H. japonica, were used for comparison. According to genome size and allozyme data, three...

Two green frog species, Rana ridibunda and hybridogenic R. esculenta, were found in Rostov Oblast', south-western Russia. The latter one was recorded in this region of Russia at the first time, providing the south-eastern range limit. Using DNA flow cytometry, we found high incidence of triploidy (96%, LLR kind) among hybrids. This is the first rec...

The banded newt, Triturus vittatus is suggested to consist of two species (T. ophryticus and T. vittatus). The northern taxon, T. ophryticus, is subdivided into two geographic fragments: the "western group" of populations from western Anatolian Turkey, and the "eastern group" distributed in the remaining part of the Pontic Turkey and western Caucas...

Staurosporine (STS) and etoposide (Eto) induced apoptosis of the human histiocytic lymphoma cells U937 were studied to determine the role of monovalent ions in apoptotic cell shrinkage. Cell shrinkage, defined as cell dehydration, was assayed by measurement of buoyant density of cells in continuous Percoll gradient. The K+ and Na+ content in cells...

The mechanism of apoptotic cell volume decrease was studied in rat thymocytes treated with dexamethasone (Dex) or etoposide (Eto). Cell shrinkage, i.e. dehydration, was quantified by using buoyant density of the thymocytes in a continuous Percoll gradient. The K+ and Na+ content of cells from different density fractions were assayed by flame emissi...

Rana esculenta complex) включает три вида — озер-ную лягушку (R. ridibunda Pallas, 1771), прудовую лягушку (R. lessonae Camerano, 1882) и съедобную лягушку (R. esculenta Linnaeus, 1758). Первые два вида являются "нормальными" диплоидными мен-делевскими видами, тогда как третий имеет не-обычное гибридное происхождение от двух пре-дыдущих и характери...

Rana esculenta complex) входит три вида: озер-ная (Rana ridibunda Pallas, 1771), прудовая (R. les-sonae Camerano, 1882) и съедобная лягушка (R. es-culenta Linnaeus, 1758). Все они широко расселены в Центральной и Восточной Европе. Ареалы этих видов на значительной территории перекрывают-ся (Ручин и др., 2005). Многочисленные исследо-вания показали,...

Eight species of the genus Triturus inhabit eastern Europe. The geographic variation in salamanders of this vast territory was poorly studied. The goal of present pa-per was to evaluate such variation, evidenced by DNA flow cytometry, allozymes and standard morphological treatments. The amount of DNA per nucleus (genome size) was measured by flow c...

Mass triploidy in hybrid Rana esculenta was revealed by means of DNA flow cytometry in 19 localities of eastern Ukraine (Kharkov, Donetsk, and Lugansk provinces). Triploids consist of two groups in terms of parental species genomes: LLR and LRR. The both groups were recorded in population systems of the E and R–E types. Two tetraploids were found a...

The Rana esculenta complex was analyzed by flow-cytometry on the materials of 2002 and 2003 years. It is established that R. ridibunda Pall., R. lessonae Camer. and R. kl. esculenta L. inhabit the zapovednik and its buffer zone. Data on species ecology and biotopic distribution are presented; 4 types green frogs population systems are found.

The main concepts of species and the relationships between them are considered using different statistical methods. The problem of cryptic species is analyzed in historical aspect. The use of biochemical (molecular) methods and the evolutionary concept of species resulted in a greater number of cryptic species in different groups of animals. Based...

In eastern Ukraine, the Rana esculenta complex consists of three species: R. lessonae, R. ridibunda, and hybrid R. esculenta. The first one was rare, whereas two latter frog taxa were very common. Based on DNA flow cyto-metry, mass occurrence of the triploidy in Rana esculenta has been revealed in 14 localities of Kharkov, Do-netsk, and Lugansk Pro...

Foundational ideas related to the concept of species and the relations they bear to different taxonomic methods are considered. The problem of cryptic species is analyzed from an historical perspective. The use of biochemical (molecular) methods and application of the concept of evolutionary species have resulted in an increase in the number of cry...

For studying S-phase dynamics with a time resolution 20 min the two combined approaches were used: 1) in the case of asynchronous cell populations decrease of velocity of progress along S-phase is registered as a local increase of S-phase distribution curve level; 2)using cell synchronization methods, nonuniformity of motion of the main maximum of...

The genome size variation in almost four hundred specimens of Pelobates fuscus fuscus, collected from 61 localities in Russia, Latvia, Belarus, Ukraine, Moldavia, and Kazakhstan, was studied by DNA flow cyto-metry. The existence of two geographic groups differed by genome size was confirmed by allozyme analy-sis. The distribution of the western typ...

We studied the influence of various methods for correction of age-related changes (administration of N-acetyl-L-cysteine, vitamins C and E, melatonin, and carnosine and swimming training) on the realization of estrogens effects in ovariectomized rats. The proliferation index in the endometrium decreased in 12-14-month-old control animals. The weigh...

The occurrence of three green frog taxa [Rana lessonae (L), R. ridibunda (R), and R. esculenta (E)] in Nizhny Novgorod Province was evidenced by DNA flow cytometry analysis. Our data are the first reliable record of the hybrid R. esculenta for the province (the Middle Volga River basin). All hybrids were dip-loid. Rana lessonae is spread throughout...

In some areas, for instance geodesy, one finds the need of suitably defining the solution of certain boundary value problems (BVPs), for instance, the Laplace equation, where boundary data are very irregular and can be described as fields of random variables, with suitable regularity constraints (Rummel and Sansò, Lecture Notes on Earth Sciences, V...

Doklady Biological Sciences, 376: 86-88

The amount of nuclear DNA in 173 specimens of Pelobates f. fuscus from 34 localities in Russia, Ukraine, Moldavia and Latvia was determined by DNA ow cytometry. Two distinct groups with different genome sizes were identii ed. The ranges of the genome size variation in the two groups did not overlap. Geographically, these groups with smaller or larg...

Following a detailed analysis of the weak solution of Neumann and oblique derivative problems [Rozanov and Sansò (1999). The analysis of the Neumann and the oblique derivative problem. Weak theory], here the so-called regularization theory is presented. The result, which is already known in mathematical literature, is obtained via a so-called Ladyz...

The cells of tumourigenic line SK-UT-1B combine features characteristic both of normal (diploid karyotype, a low level of polyploid cells, absence of chromosomal marker) and tumour cells (high level of chromosomal instability, high malignancy). We suggest that maintenance of diploid karyotype in this line is controlled via the p53/p21 pathway. We d...

Thymocyte cell death was investigated after UVA-irradiation (365 nm) of the primary thymocyte culture in vitro. To determine the mode of cell death two fluorescent DNA-binding dyes (Acridine Orange and Ethidium Bromide) were used along with flow cytometry. Thymocytes undergo apoptosis spontaneously, but a percentage of apoptotic cells was seen to i...

The amount of nuclear DNA in 173 specimens of Pelobates f. fuscus from 34 localities in Russia, Ukraine, Moldavia and Latvia was determined by DNA ow cytometry. Two distinct groups with different genome sizes were identii ed. The ranges of the genome size variation in the two groups did not overlap. Geographically, these groups with smaller or larg...

Nuclear DNA content in 1547 specimens representing 22 species of Salamandridae and 3 species of Hynobiidae was measured by means of flow cytometry. Genome size differences among various taxa were studied. Relations between nuclear DNA contents and distribution, paedomorphosis and hybridisation were examined. Five cases of spontaneous triploidy and...

15 specimens from western Turkey, northern and southern Iran were examined. According to external characters and geographic position, the toads seem to belong to B. v. viridis , to the so-called Transcaspian population group, and to B. v. kermanensis, respectively. The diploid level of toads was evidenced from DNA flow cytometry. The distribution o...

Genome size, protein variation and morphological characteristics of three crested newt species (Triturus cristatus, T. dobrogicus, and T. karelinii) have been studied from Serbia and from the eastern parts of the species ranges. The Serbian samples of T. karelinii are distinct from other populations of the species, and we recognize the Balkan newts...

Recent statistical analysis of the folding of G0/G1 chromosomes using fluorescence in situ hybridization (FISH) allowed development of a random walk/giant loop model of chromosome structure. According to this model there are two levels of organization of G0/G1 chromosome fibres. On the first level, the fibres are arranged in giant loops several Mbp...

In this review paper the simple Neumann and oblique derivative problem is formulated for an exterior domain and mapped by the Kelvin-Raleigh transform, to an internal domain. The weak formulation of the two problems is subsequently studied and standard theorems of existence, uniqueness and well-posedness are proved. The conditions of validity for s...

Recent statistical analysis of the folding of G0/G1 chromosomes using fluorescence in situ hybridization (FISH) allowed development of a random walk/giant loop model of chromosome structure. According to this model there are two levels of organization of G0/G1 chromosome fibres. On the first level, the fibres are arranged in giant loops several Mbp...