[TRANSFORMATIONS OF LIFE CYCLES IN THE EVOLUTIONARY HISTORY OF TRYPANOSOMATIDS. ENDOTRANSFORMATIONS AND ABERRATIONS].

Endotransformations and aberrations of the life cycle in the evolutionary history of trypanosomatids (Kinetoplastea: Trypanosomatidae) are analyzed. We treat the term "endotransformations" as evolutionarily fixed changes of phases and/or developmental stages of parasites. By contrast, we treat aberrations as evolutionary unstable, periodically arising deformations of developmental phases of trypanosomatids, never leading to life cycle changes. Various examples of life cycle endotransformations and aberrations in representatives of the family Trypanosomatidae are discussed.

[TRANSFORMATIONS OF LIFE CYCLES IN THE EVOLUTIONARY HISTORY OF TRYPANOSOMATIDAE. EXOTRANSFORMATIONS].

The present review is devoted to the analysis of exotransformations of life cycles in the evolutionary history of trypanosomatids (Kinetoplastea: Trypanosomatidae). Exotransformations are treated as processes associated with the transition of a trypanosomatid to a new host. The result of these transformations comprises both the inclusion of new hosts in life cycles of parasites and also epy formation of parasitic systems de novo. It is shown that exotransformations are one of the main modi in the evolution of trypanosomatids. Different examples of exotransformations of life cycle in all the taxonomic groups of Trypanosomatidae are given.

[TRANSFORMATIONS OF LIFE CYCLES IN THE EVOLUTIONARY HISTORY OF TRYPANOSOMATIDS. MACROTRANSFORMATIONS].

The review concerns analysis of life cycle macrotransformations in the evolutionary history of trypanosomatids. The term "macrotransformations" stands for evolutionary processes leading to the establishment of heteroxenous and secondary homoxenous life cycles within Trypanosomatidae. There were three direct macrotransformations in the evolution of the group resulting in the rise of heteroxenous genera Leishmania, Trypanosoma and Phytomonas, and one case of reverse macrotransformation in trypanosomes of T. (b.) brucei group. The issues of the origin, diversity and phylogeny of taxa whose emergence resulted from macrotransformations of life cycles of homoxenous trypanosomatids.

[Early stages of development of Trypanosoma rotatorium (Mayer, 1843) from peripheral blood and internal organs of Anurans Bufo bufo (Linnaeus) and Rana sp. (Anura)].

The data on the fauna of trypanosomes of Anura of the Leningrad Province are given. The initial development stages of Trypanosoma rotatorium in peripheral blood and internal organs of the frog are described for the first time.

[Homoxenous trypanosomatids from true bugs Pyrrhocoris apterus (L.) in the north of the Pskov region].

In the north of the Pskov region (58 degrees 35' N, 28 degrees 55' E) the appearance of a single colony of true bugs Pyrrhocoris apterus has been recorded. Dissection of 95 individuals from this colony revealed 100% prevalence of infection with homoxenous trypanosomatids. In 3% of the cases intestinal infection was accompanied by hyperinvasion into the salivary glands and hemolyph of the hosts. Analysis of trypanosomatid morphotypes demonstrated mixed infections in all studied P. apterus individuals. At least 4 forms of promastigotes along with epimastigotes, choanomastigotes and amastigotes were found. The distribution of the trypanosomatid morphotypes over all intestinal parts as well as salivary glands and hemolymph was investigated. Three isolates of the flagellates were deposited into the living cultures collection of the laboratory of Protozoology of the Zoological institute of the Russian Academy of Sciences.

[Investigation of causes of the conflict between taxonomy and molecular phylogeny of trypanosomatids by the example of Leptomonas nabiculae podlipaev, 1987].

Results of study of Leptomonas nabiculae using various molecular markers and different material (cultures D2 et Nfm2) contradicted each other and taxonomic position of this species. We investigated morphology of the cells in these cultures as well as in hapantotype of L. nabiculae and those of L. peterhoffi and L. occidentalis that had been described from the same host species. We also reconstructed 18S rRNA gene phylogeny using sequences from both cultures. The D2 culture according to its morphology and phylogenetic position revealed to be a Crithidia that had accompanied L. nabiculae in a mixed infection. We named it Crithidia dedva. The cells in the hapantotypes of the three Leptomonas species and those of the Nfm2 culture represent a single species that is a Herpetomonas (H. nabiculae) judging by morphology and molecular phylogeny. We also showed that the sequence of 18S rRNA gene that had been formerly determined represents a chimaera. This had resulted in the wrong position of this species on the phylogenetic tree that had contradicted results of the analysis of 5s rRNA gene.

[Light- and electron-microscopical study of Pelomyxa flava sp. n. (archamoebae, pelobiontida)].

Using light and electron microscopy, the morphology of a new species of pelobionts Pelomyxa flava was studied. The coverings of P. flava are represented by plasma membrane bearing the thick layer of weakly structured glycocalyx on its outer surface. Numerous flagella are often located on the tops of short conical pseudopodia. Kinetosomes of flagella reach a length of 0.9 microm and are hollow with a pronounced central filament. Rootlet system is represented by three groups of microtubules: the radial, basal and microtubules of lateral root. The transition zone is short and does not exceed the level of cell surface; the axoneme is characterized by an unstable set of microtubules. Trophic stages of P. flava life cycle are presented by binuclear cells; plasmotomy is performed at the tetranuclear stage. Nuclei have a granular structure. Fibrillar nuclear bodies were revealed in karyoplasm. The nuclei shell has a complex organization. On its surface, the outer membrane has a layer of electron-dense material which contacts with short microtubules, located in a row at the surface of the nuclear envelope. The bubbles and cisterns of endoplasmic reticulum, which are the derivatives of the nuclear envelope, are located outward from the microtubules. The presence of structural and digestive vacuoles and grains of glycogen was noticed in P. flava endoplasm. Three types of prokaryotic cytobionts were revealed. Large multi-membranous organelles reaching 5 pm in diameter were described for the first time. We discuss morphology and biology features of P. flava in comparison with the previously studied Pelomyxa species.

[Fauna of haemoparasites of batrachians (Amphibia, Anura) in Kyrgyzstan].

Fauna of haemoparasites of batrachians is studied in Kyrgyzstan for the first time. Descriptions of 12 haemoparasites species are given. Eight species have been found in Central Asia for the first time.

[On the problem of identification of homoxenous trypanosome cultures with the description of a new species Wallaceina podlipaevi sp. n. (Kinetoplastida: Trypanosomatidae)].

The type culture of Leptomonas peterhoffi Podlipaev, 1985 (stamm P-101) was examined using light and electron microscopy. The hapantotype of L. peterhoffi Podlipaev, 1985 was reexamined with a light microscope. As a result, a new species of homoxenous trypanosomes, Wallaceina podlipaevi, sp. n. was described.

[The morphological study of the cysts Pelomyxa palustris Greeff, 1874].

Pelomyxa palustris Greeff, 1874, is the only species of pelomixoid amoebas with the rest cysts in its life cycle. The morphology of the P. palustris has been studied by the light and electronic microscopy. Encystation of P. palustris under climatic conditions of North-West of Russia occurs within August-September. Rest cysts have a complex, trilaminar wall. Two inner lamina are the dense endocyst and the laminated mesocyst, thickness of each layer runs up to 0.6-0.7 microm. Thickness of the electron-dense ectocyst usually does not exceed 0.1-0.2 microm. The encystated cell of P. palustris has the unique structure. About 60 % of the cell volume are occupied by a huge vacuole placed in the center and filled up with the prokaryotic cytobionts. Different vacuoles, small vesicles of various nature, autophagosomes and lipid drops could be found inside that huge vacuole. The amoebae cytoplasm occupies the space in between endocyst's inner surface and the central vacuole. No any inclusions, prokaryotic cytobionts and most of cell organelles are absent in the cytoplasm. There are 4 large nuclei filled with relatively homogeneous karyoplasm lying in the cytoplasm. Nuclear envelope forms a lot of long tubular channels, running through the cytoplasm and lining the membrane of the central vacuole. Encysted pelomixoid stay in this state up until the beginning of excystation. Excystation of P. palustris in the studied region occurs in spring, during the latter half of April and the beginning of May. Cysts undergo complex morphofunctional changes, related to the reorganization of the wall and formation of young multinucleate amoebas. Only one wall lamina of the 3 initial ones is left up to the moment of excystation. The central vacuole endures ruination and its content penetrates into the cytoplasm. Pelomixoid nuclei divide twice. Prokaryotic cytobionts are localized in cytoplasm and in the perinuclear area. Young multinuclear species of P. palustris coming out of the cysts do not differ in their structure from the adult forms.

[Mitosis in the free-living flagellate Bodo saltans strain PS+ (Kinetoplastidea, Bodonida)].

The mitosis in the free-living flagellate Bodo saltans Ps+ with prokaryotic cytobionts in perinuclear space has been studied. The nuclear division in B. saltans Ps+ occurs by closed mitosis type without condensation of chromosomes. Two spatially separated mitotic spindles begin to form consistently at the initial stages of nuclear division. The spindle including about 20 microtubules appears first and later the second spindle with half the number of microtubules comes at the angle of 30-40 degrees. Both spindles rest their ends against the inner nuclear membrane and form 4 distinct poles. The microtubules of the first spindle are associated with 4 pairs of kinetochores, the microtubules of the second one are associated with 2 pairs of kinetochores. The divergence of the kinetochores towards the poles occurs independently in each spindle. The equatorial phase is not revealed in B. saltans Ps+. The poles of both spindles unite in pairs at the elongation phase of mitosis and form the integrated bipolar structure. At this stage of the nuclear division, the kinetochores reach the poles of subspindles and become indistinguishable. Then the nucleus takes the shape of a dumbbell. The inner nuclear membranes of just formed nuclei have layers of condensed chromatin characteristic of the interphase nuclei of kinetoplastidea. The daughter nuclei separate at the phase of reorganization. There are 1-2 prokaryotic endocytobionts in the perinuclear space of the interphase nuclei in B. saltans Ps+. The symbionts multiply during mitosis and their number reaches more than 20 specimens par nucleus.

[Development of cyst-like cells of the flagellate Leptomonas oncopelti in the midgut of the hemipteran Oncopeltus fasciatus].

The structure of cyst-like cells of Leptomonas oncopelti (Trypanosomatidae) found in the midgut of the bug Oncopeltus fasciatus (Lygaeidae) was examined with light and electron microscopy. The formation of "cysts" begins with an unequal division of active flagellates with promastigote configuration. Cytokinesis starts on the lateral side of the flagellate, and then the cleavage furrow moves toward the apical end of the cell. The anterior part of a smaller daughter cell, referred to as cell C1, remains associated with the flagellum of maternal promastigote. C1 divides twice to give rise first to two equivalent cells (C2), and then to four morphologically similar cells (C3). C2 join with each other, and afterwards C3 attach between themselves as well via short cytoplasmic outgrowths, which appear instead flagella. In the point of outgrowth attachment of only one C2 and then of only one C3 to maternal flagellum zonal desmosomes occur. C1--C3 of L. oncopelti are similar to so-called straphangers (cyst-like parasites attached to the flagellum of maternal promastigote) known in some species of the genera Leptomonas and Blastocrithidia. Basal bodies are present in C1 and C2 but not in C3. DNA fibrils in the kinetoplast lack their common circular configuration, they progressively condense to form a disordered mass. C3 chromatin becomes denser to acquire eventually a characteristic "labyrinthine structure" looking like a huge bundle of whorled filaments 3-5 nm width. Inside this bundle there are channels of 10-12 nm in diameter filled with karyoplasm. On becoming ovoid, C3 are separated from the maternal promastigote flagellum and differentiate into mature "cysts". Straphangers C1--C3 and mature "cysts" lack any visible outer extracellular protective envelope (cyst wall). Instead, these cells have a cortical complex made of a reinforced plasmatic membrane underlined by a layer of a dense granular cytoplasm free of subpellicular microtubules. The mature "cyst" endoplasm shows a high electron density, and because of this identification of the majority of cellular organelles is next to impossible. Nevertheless, in both C3 and mature "cysts" some unusual membranes are seen composed of two electron lucent layers, with a single electron dense layer in between.

[Light and electron microscopic investigation of Pelomyxa prima (Gruber, 1884) (Peloflagellatea, Pelobiontida)].

Cell organization of a multinuclear pelobiont Pelomyxa prima has been studied at the light and electron microscopic levels. Motile individuals demonstrate a characteristic drop-like or pyriform shape and reach 550 microkm in length. The cell cover is represented by a well-developed, morphologically differentiated glycocalyx 80-100 nm thick. The cytoplasm contains many structural vacuoles. The nuclei are of vertical type, numbering up to several nuclei in large individuals. Numerous cytoplasmic microtubules are associated with the external membrane of the nuclear envelope. Separate non-motile flagella are distributed throughout the cell surface, being more numerous in the posterior body end and uroidal zone of the protist. Basal bodies of the flagella are extremely long, being deeply immersed into the cytoplasm. These bodies are surrounded by a muff of electron-dense material, with numerous microtubules radiating from it. A compact bundle of microtubules starts from the base of a basal body axially into the cytoplasm. Besides, a band-like lateral microtubular rootlet is present. The number of microtubules in the axoneme of undulipodia is unstable. Neither mitochondria, nor Golgi complex were found. Two species of bacterial endocytobionts are present in the cytoplasm in considerable numbers.

[The description of Wallaceina vicina sp. n. (Kinetoplastida: Trypanosomatidae), from the water strider Gerris rufoscutellatus Latreille, 1807 (Hemiptera: Gerridae)]. / Opisanie Wallaceina vicina sp. n. (Kinetoplastida: Trypanosomatidae) iz klopa-vodomerki Gerris rufoscutellatus Latreille, 1807 (Hemiptera: Gerridae).

A new homoxenos trypanosomatidae, Wallaceina vicina sp. n., is described from the digestion tract of the water strider Gerris rufoscutellatus. The laboratory culture of W. vicina has been obtained. Flagelated have been studied with TEM.

[The description and laboratory cultivation of Leptomonas repentinus sp.n. ( Kinetoplastida: Trypanosomatidae)--a parasite of the water strider Gerris rufoscutellatus]. / Opisanie i laboratornoe kul'tivirovanie Leptomonas repentinus sp.n. (Kinetoplastida:Trypanosomatidae)--parazita klopa-vodomerki Gerris rufoscutellatus.

A new homoxenos trypanosomatide, Leptomonas repentinus sp. n., is described from the digestion tract of the water strider Gerris rufoscutellatus. The laboratory culture of L. repentinus has been obtained. Cultural stages of L. repentinus have been studied with TEM. The mitochondrion and kinetoplast have unusual structure. Large symbiont-like spherical bodies have been found in the mitochondrial matrix.

[Ultrastructure of the flagellate Cruzella marina (Kinetoplastidea)]. / Ul'trasruktura zhgutikonostsa Cruzella marina (Kinetoplastidea).

The ultrastructure of a marine, free-living heterotrophic kinetoplastid Cruzella marina was investigated with special attention being paid to the mitochondrion and flagellar organization. The flagellates have a polykinetoplastidal mitochondrion. Two flagella emerge from the pocket; one of these turns anteriorly being forward-directed, while the other is posteriorly directed to be adjacent to the ventral cell surface. The transition zone of both the flagella includes central filaments. The cytostome opens on the tip of the rostrum. The cytostome leads to the channel of cytopharynx, which penetrates the rostrum and proceeds into the flagellate body cytoplasm. The comparison of the relevant morphological and molecular data suggest that C. marina may arise early in the Kinetoplastidea lineage, before divergence of the majority taxa of the kinetoplastid flagellates.

[Ultrafine organization of Leptomonas peterhoffi flagellates cultured in broth and solid nutrient media]. / Issledovanie ul'tratonkoi organizatsii zhgutikonostsev Leptomonas peterhoffi, kul'tiviruemykh na zhidkoi i tverdoi pitatel'nykh sredakh.

The morphology of in vitro grown lower trypanosomatids L. peterhoffi was studied by means of electron microscopy. The flagellates from both liquid and solid culture media are represented by uninucleate cells of two structural types. Type I flagellates are characterized by dense cytoplasm enriched with numerous ribosomes. Type II flagellates are most abundant in the cultures; they display a less dense cytoplasm and fewer ribosomes. The flagella of L. peterhoffi of both types form enlargements, which are most expressed at the outlet of the flagellar pocket. The nuclei of some cells contain twisted threads about 10 nm in diameter. L. peterhoffi from the liquid media usually possess long, narrow and curved flagellar pockets. On the solid medium, amoeboid and hemispherical colonies composed of both uninucleate and giant multinucleate cells are formed. In these cells the flagellar pockets are usually short and straight. Outside the flagellar pocket, the axoneme often becomes looped in the flagellar enlargements of the colonial uninucleate cells.