[Neonatal gastroenteritis triggers long-term cardiomyocyte atrophy, remodeling and irreversible hyperpolyploidization].

Growth retardation, inflammation and cardiac overload in early childhood are linked with hypertension and infarction in adults. This link was termed as developmental programming. Exact mechanisms and critical time frames for development of the heart are still unknown. To elucidate these questions, we developed a model of moderate cryptosporidial gastroenteritis triggering main programming factors. Sliding the time point of infection day by day (from day 4 to day 18), we tested complete rat neonatal period. Also, we repeated all experiments 30 days after infection. Using methods of cytometry, immunocytochemistry and confocal microscopy, we compared sensitivity of ventricular cardiomyocyte shape, protein content and ploidy. Our data indicated that gastroenteritis lasting four days triggered cardiomyocyte atrophy, almost doubling cell length to width ratio, and premature and excessive polyploidization. Surprisingly, nucleus and cytoplasm reacted to the disease differently. Cardiomyocytes accumulated genomes only when the disease covered the time period between 6 and 14 days after birth, when cells substitute proliferative growth with hypertrophy. Contractile proteins and cell shape on the contrary, showed high sensitivity in the course of complete neonatal period. After restoration, ploidy did not regress, whereas cell shape and protein content revealed moderate restoration. Taking into account that somatic polyploidy is irreversible and that it alters global gene expression pattern, we may suggest that genome duplication is one of the instruments of developmental programming and that gastroenteritis is one if the triggers of this programming.

[The ultrastructural changes of Sarcocystis ovifelis infested sheep tongue myofibrils].

Structural changes were observed in filaments of Sarcocystis ovifelis infected sheep tongue myofibrils. In sarcocysts containing myofibrils, actin filaments and Z-disks, myosin filaments and M-line were seen destroyed. Protein bridges, uniting actin and myosin filaments into a joint complex (net), eventually become not visible, and as a result separate Z-disks and free filaments appear. Fibrils, referred to as leptomeric, have been first revealed between protrusions of the sarcocyst surface apparatus. These are striated filaments with periodic 100 nm striation of dark and light bands, made of thin and short 120-200 nm long filaments 5 nm in diameter. The genesis of leptomeric fibrils still remains obscure. In sarcocysts infected myofibrils these may be involved in metabolite transportation to the intercellular space and back.

[Intestinal cryptosporidiosis at an early age and its negative consequences].

This review calls the attention of physicians, primarily pediatricians, to cryptosporidiosis, a still little known intestinal infection caused by the protozoan pathogen Cryptosporidium parvum (Coccidia, Sporozoa). By using 10--14-day rats as a model, the authors have first provided evidence that even 4-day intestinal cryptosporidiosis may trigger obvious negative changes in the liver and heart, i.e. in the organs where the parasite does not develop. In the infected rats, growth retardation was registered, in addition to liver hypertrophy and partial heart atrophy, and growth retardation. Light and electron microscopies, absorption and fluorescence cytometry, quantitative morphometry, and image analysis were applied. In both hepatocytes and cardiomyocytes, the polyploid cell fraction was seen much increased, with the occurrence of 4c, 8c, and even 16c nuclei. Besides, in the hepatocytes, the amount of glycogen decreased whereas the level of protein increased, along with enhanced nucleolar activity in the nuclei. Unlike, the cardiomyocytes of the infected rats were characterized by protein decrease, in addition to almost two-fold cell body elongation. This is the first documented evidence for serious pathological changes in the extraintestinal organs, caused by the intestinal pathogen C. parvum. Within the first 4 days of infection, both the liver and heart of the host seem to work under stress. It is plausible that on modulating liver and heart ploidy, the intestinal parasitic infection (cryptosporidiosis) may bring about functional impairments of these organs, untypical of early age, leading eventually to long-term consequences in further life of formerly infected individuals.

[The structural and functional analysis of the surface apparatus in four species of Sarcocystis (Sporozoa, Apicomplexa)].

The comparable ultrastructural analysis of the sarcocyst surface apparatus (SSA) was made for four species of Sarcocystis: Sarcocystis muris, S. fusiformis, S. medusiformis, and Sarcocystis sp. from buffalo heart muscles. In all these species, SSA contains a surface membrane, overmembrane complex with glycocalyx, and submembrane complex made of two glycoprotein SSA primembrane layers. SSA makes numerous primary vesicle-like protrusions and pits in between. Some vesicles containing two layers, PM1 and PM2, are pinching off from the totally formed protrusions. Then these vesicles are directed into infected host cell to participate in its degradation. In the SSA pits neither over-, nor submembrane complex is present, the pits being made of the surface membrane only. It is important that fibrillar structures penetrate through the SSA membrane into pits from the host cell. Besides, SSA forms secondary protrusions with different structures in various species of Sarcocystis. They increase the sarcocyst surface and transport different substances along intermediate filaments from the SSA pits membrane to the sarcocyst body. At the same time, deep invaginations are found in the SSA of old sarcocysts. We thought that these structures increased the sarcocyst surface and thus promote to intensify metabolism. This study-defined presence of membranous vesicles in secondary protrusions. According to their structure and localization, the membranous vesicles may be involved in the building of the sarcocyst surface membrane.

[Interaction between Karyolysus sp. and rock lizard liver cells during hibernation]. / Vzaimodeistvie mezhdu koktsidiei Karyolysus sp. i kletkami pecheni skal'nykh iashcherits v period zimnei spiachki.

During the rock lizard hibernation, no nuclear division occurs in the exoerythrocytar trophozoites of Karyolysus sp., found in hepatocytes or Kupffer's cells. In addition, organelles of the apical complex are seen persisting in these trophozoites, unlike the situation routinely observed in the majority of other intracellular sporozoans. Thus, the parasites under study can be compared with hypnozoites of other coccidia. The material being examined from natural rather than experimental conditions, during lizards' hibernation, the dynamics of host-parasite interrelations can be followed that involves the appearance in the infected cell of autophagous vacuoles, changes in mitochondrial structure and pattern of endoplasmic reticulum, the connection of the system of lamellar channels with the space of the parasitophorous vacuole. The results of the present observations may suggest, first, that during the host hibernation, exoerythrocytar trophozoites of Karyolysus being intracellular in their spatial distribution, are able to obtain nutrients from the outer, extracellular space, through the system of lamellar channels; second, that these channels can represent intercellular connections, which makes one consider the exoerythrocytar trophozoites as intercellular rather than intracellular parasites.

[Electron microscopic research on cryptosporidia. III. Parasite-host relations]. / Elektronno-mikroskopicheskoe issledovanie kriptosporidii. III. Parazito-khoziainnye otnosheniia.

A study was made of the host-parasite relationship with Cryptosporidium parvum (Apicomplexa, Sporozoa), which parasitizes the intestine of newborn rats experimentally infected with oocysts isolated from C. parvum-infected calves. The endogenous development of the parasite occurs extracytoplasmically in the microvillar compartment of the enterocytes. The formation of the extracytoplasmic parasitophorous vacuole (PV), like that surrounding the endogenous stages of C. parvum, is regarded as one of the possible and evolutionary established ways for the intracellular parasite to escape from the host cell lysosomal digestion. Special attention is paid to the attachment zone of C. parvum, where a multimembranous organelle is formed serving eventually as a feeder organelle. No other specialized cytostome, similar to the micropore of other coccidia, has been so far revealed in the growing stages of Cryptosporidium. The characteristic ultrastructural organization of the endogenous stages of C. parvum and of other Cryptosporidium species so far investigated, along with the peculiar structure of the cryptosporidia-surrounding PV, to say nothing of some other distinctive features--all this makes it possible to distinguish between the genus Cryptosporidium and other coccidian genera, and warrants the separation of the former into a separate family Cryptosporidiidae Léger, 1911. Unlike, the addition to this family, besides Cryptosporidium Tyzzer, 1910, of another genus, Epieimeria Dykova, 1981, on the ground of the "epicellular" localization of both the genera claimed by Levine (1984), seems hardly correct, due to the totally different patterns of ultrastructural organization and host-parasite relationship recently reported for Epieimeria anguillae by Molnar and Baska (1986).

[The structure of the surface apparatus in sarcocysts of Sarcosporidia in the persistence process]. / Strukturnaia organizatsiia poverkhnostnogo apparata sarkosporidii v protsesse persistirovaniia.

The structure of the sarcocyst surface apparatus (SSA) was investigated for two sarcosporidian species: Sarcocystis muris (non-pathogenic) and S. fusiformis (pathogenic). The surface membrane, being the main SSA subsystem, makes numerous vesicle-like protrusions with different ultrastructural patterns. This made it possible to distinguish between four and three types of these protrusions in S. fusiformis and S. muris, respectively. Vesicles of similar structure, pinched off from the fully formed protrusions, were classified, correspondingly, in the same four and three different types. A presumable functional role of both protrusions and membrane-coated vesicles in pathogenicity of different sarcosporidian species is proposed. The vesicles pinched off from corresponding protrusions may be involved in transporting certain substance complexes from the sarcocyst to the harbouring host cell. In addition, another way of substance transporting was observed, when the cystic substances, not surrounded with any membrane coating, are thrown from open protrusions directly into the immediate cytoplasm of the host cell.

[An electron microscopic study of the natural death of cyst cells in Sarcosporidia. II. Ultrastructural changes in the nuclei of cyst cells of Sarcocystis muris]. / Elektronno-mikroskopicheskoe issledovanie estestvennoi gibeli tsistnykh kletok u sarkosporidii. II. Izmenenie ul'trastruktury iader tsistnykh kletok Sarcocystis muris.

Nuclear changes in cyst cells, developing within 6 and 10 month old sarcocysts of Sarcocystis muris, were followed in terms of the programmed cell death phenomenon. This communication extends our previous studies in the cytoplasm of S. muris cyst cells (Radchenko et al., 1995) to include particular nuclear changes in different involve changes in nuclear configuration: the original spherical from is progressively substituted for irregular or lobulated shapes. This may suggest some corresponding changes in cytoskeleton, involved in formation and maintaining of some definite nuclear shape. In normal cyst cells, the nuclear chromatin appears as a filiform and reticulate structure with a few lumps made of granules and filaments. In the cyst stages subject to natural cell death, structural changes in nuclei involve disassembly of lumps into separate granules. Some spherical structures are seen outbudding from the nucleolus. These structures are presumably made of RNA-containing granules. The pattern of nucleolar segregation in S. muris cells resembles somewhat the changes in nucleoli reported for metazoan cells. However, the general picture of morphological evolution in the nuclei of S. muris cells, in the course of natural dying, differs from that in metazoan cell nuclei. No condensation of nuclear chromatin at the nuclear periphery, or blebbing of the nuclear and cytoplasmic membranes, so characteristic of the latter, was followed in the former. The peculiarities noticed in the sarcosporidia may reflect biological peculiarities of these specialized parasitic protozoa.

[The role of the sarcocyst surface apparatus in utilizing the host cell muscle structures]. / Rol' poverkhnostnogo apparata myshechnykh tsist sarkosporidii v protsesse utilizatsii struktur myshechnoi kletki khoziaina.

The participation of the sarcocyst surface apparatus (SSA) of two sarcosporidian species, Sarcocystis muris and S. ovifelis (Coccidia, Sporozoa, Apicomplexa), in degradation of disrupted host cell substances was investigated. After degradation, these substances are transported through the membrane of the SSA to the sarcocyst ground substance (GS), but this process cannot be regarded as endocytosis. At first, the transported substances were found in SSA pits in the form of fibrillar structures. Later on, these were seen as twisted up granules. In some cases, such granules restore their fibrillar shape, penetrate through the SSA membrane and appear in the sarcocyst GS. In other cases, the small granules may be released from SSA pits directly to the sarcocyst GS. Besides, two SSA primembrane layers were seen to disappear during the transportation of host cell substances. In addition, multimembrane structures (membranous whorls) were first demonstrated between the plasmalemma and inner membrane complex of the zoite pellicle. Multimembrane structures were found, in addition, in the zoite cytoplasm in connection with micronemes. These structures resembling chloroplast granae of thylakoids may presumably fill the gap in membrane pool of the SSA contributing to its renewal.

[Structural and functional characterization of cyst cells in Sarcocystis sp. (Sporozoa, Apicomplexa)]. / Osobennosti stroeniia i funktsional'nye kharakteristiki kletok v tsistakh sarkosporidii.

By means of light and electron microscopy, the structural pattern of muscle cysts (sarcocysts) was examined for the four species of the genus Sarcocystis: S. muris (from murine skeletal muscles), Sarcocystis sp. and S. fusiformis (from, respectively, heart and skeletal muscles of buffalo), and S. ovifelis (from ovine tong muscles). The orderly fashion of the interior of the cyst is attained by partitition of its space into numerous compartments with the involvement of the intermediate filaments. These, in their turn, are bound to each other by thin filaments to make eventually a common filamentous net. The net limits separate groups of cells referred to as cyst zoites. The common net of filaments and microtubules (when present) may be regarded not only as the organizer of the cyst interior cytoskeleton, but also as the main mechanism of substance transportation in various directions: from the host cell to the sarcocyst, and within or outside the cyst. The role of dedifferentiation, proliferation and differentiation processes is suggested in the establishment of the fixed sequence of events throughout the unidirectional development of cyst cells and their interaction, from precystic meronts to cyst merozoites (gamonts). Special attention is paid to metrocyte morphogenesis and functioning. In the present work, metrocytes subjected to apoptosis were recognized. It is suggested that phenomenon of programmed cell death in metrocytes may be associated with the control of cell number in mature and ageing sarcocysts.

[Effect of developing Sarcocystis muris tissue cysts on ultrastructural change of murine muscle fibers]. / Vliianie razvivaiushchikhsia tkanevykh tsist Sarcocystis muris na izmenenie ul'trastruktury myshechnogo volokna myshi.

A study was made of the influence exerted by developing sarcocysts of Sarcocystis muris on the ultrastructural organization of muscle fibres, both harbouring the sarcocysts (HSM) and sarcocyst-free (SFM), from skeletal muscles of experimentally infected mice. Muscle fibres of non-infected mice of the same age served as a control. Mice were sacrificed 6 months following feeding S. muris oocysts (or sporocysts). The developing sarcocysts seriously destroyed HSM: their myofilaments were no hold in register, cross-bridges almost entirely disappeared, M-lines and Z-disks looked as broken structures. The majority of actin myofilaments were arranged along myosin myofilaments as discrete units. The host cell sarcoplasm was packed with numerous vacuoles of different form and size. Compared to muscle fibres in the control, SFM of infected mice also displayed an obvious ultrastructural alteration. On the periphery of SFM, some destroyed sarcomeres with swollen myofilaments were noticed whose cross-bridges were totally lacking. In other extreme areas myosin and actin myofilaments were disintegrated into thin straightened filaments 2.0-2.5 nm in diameter. It is supposed that HSM and SFM of the infected mice may experience different kinds of influence on the part of the developing intracellular parasite (sarcocyst). And it dos not seem unlikely that various biologically active substances, produced by the parasite, may be vesicle transported to SFN through the endomysium space.

[The effect of coccidia of the genus Sarcocystis on the morphofunctional organization of the skeletal musculature in experimentally infected mice. II. The connective tissue elements of the endomysium]. / Vliianie koktsidii roda Sarcocystis na morfofunktsional'nuiu organizatsiiu skeletnoi muskulatury éksperimental'no zarazhennykh myshei. II. Soedinitel'notkannye élementy éndomiziia.

As an extension of the previous communication (Radchenko, et al., 1996), a study was made of the response of connective tissue elements, surrounding the Sarcocystis muris infected muscle fibers. As earlier, the S. muris sarcocysts were examined in mice 1, 2.5, 6, and 10 months after sporocyst feeding. Within the first 2.5 months after infection, marked accumulations of lymphocyte-like cells and collagen fibres are observed in the endomysium, and simultaneously the activity of capillary endothelial cells is seen to enhance due to the appearance of much more micropinocytotic vesicles, compared to the uninfected control. All this may be qualified as the host organism protective reaction to the parasitic infection. 6 and 10 months after infection, not only collagen fibres, but also some other fibrillar structures of the endomysium undergo degradation, the damage of capillary endothelial cells starting from breaking the outer membrane (in 6 months) and terminating in lysing the whole cell (in 10 months). Besides, structural abnormalities were noticed in the axon endings.

[An electron microscopic study of Cryptosporidium. II. The stages of gametogenesis and sporogony in Cryptosporidium parvum]. / Elektronno-mikroskopicheskoe issledovanie kriptosporidii. II. Stadii gametogeneza i sporogonii kriptosporidii Cryptosporidium parvum.

The ultrastructure of stages of gametogony and sporogony of C. parvum from the intestine of experimentally infected suckling rats was studied by transmission electron microscope. Unlike merogony, in which the whole cytoplasm of the mother meront is used up for the merozoite formation, during microgametogony the large residual mass of gamonts remains in contact with the feeder organelle even after microgamete outbudding. Unlike other coccidia, during the microgametogenesis in C. parvum, the nuclear substance of the daughter nuclei is not separated into osmiophilic (containing the condensed chromatin) and achromatinic parts. The gamete outbudding in C. parvum is accompanied by evagination of the pellicle of the mother gamont whose cytoplasm displays some slit-like canals that seem to sequester the daughter nuclei with some portion of the surrounding cytoplasm. The flagella-free microgametes of C. parvum resemble somatic cells, rather than male sexual cells of other coccidia. The study of thick-walled oocysts of C. parvum made it possible to suggest that the fragile wall of the oocyst proper may be easily destroyed in the course of processing of the material to look eventually as a ghost of electron lucent substance in the parasitophorous vacuole, whereas the structures revealed on the electronograms may presumably represent the outer and inner layers of the sporocyst. If so, the suture described elsewhere in the cryptosporidial oocysts, is to be considered as belonging to the sporocyst wall rather than to the oocyst wall, i.e. likely as in other investigated coccidia. However, the question on the mode of sporozoite excystment in the thin-walled oocysts of C. parvum still remains obscure.

[An electron microscopic study of the natural death of cyst cells in Sarcosporidia. I. Ultrastructural changes in the cytoplasm of the cyst cells of Sarcocystis muris and S. bovifelis]. / Elektronno-mikroskopicheskoe issledovanie estestvennoi gibeli tsistnykh kletok u sarkosporidii. I. Izmenenie ul'trastruktury tsitoplazmy tsistnykh kletok Sarcocystis muris i S. bovifelis.

A complicated development of Sarcocystis muris and S.bovifelis, within tissue cysts (sarcocysts), was examined in terms of a phenomenon of programmed cell death well-known in Metazoa. It looks likely that this phenomenon of versatile significance in living organisms has not yet been followed in parasitic protozoa. This is the first attempt to find out a general picture of morphological changes, occurring in the course of natural death in parasitic protozoa. With electron microscope, a study was made of sarcocysts of S. bovifelis isolated from oesophagus muscles of a naturally infected cow. In 6-month old sarcocysts of S. muris, three morphofunctional cell types are commonly distinguished: little differentiated metrocytes, intermediate cells, and highly differentiated <>, homologous to gamonts of other Sporozoa. Among numerous cyst cells, looking overtly normal, some <> cells tend to be encountered, which increase in number in 10 month old cysts, i.e. as sarcocysts are getting older. At least three stages of morphological degradation are to be distinguished in the cyst cells, with special attention being paid to changes in their cytoplasm. The first stage degradation involves ultrastructural changes in cell organelles, primarily in rough endoplasmic reticulum, whose membranes form vacuoles, with various kinds of membranous and non-membranous materials inside. At the second stage, apical organelles of cyst cells are involved: rhoptries are seen to lose their contrast, suggesting that their proteinaceous content may be discharged into the cell cytoplasm; eventually, membranes of rhoptries disappear. Micronemes seem to break into composing channels of endoplasmic reticulum. Ultimately, in the cells committed to death, the main body of cell organelles looks indecipherable, and the whole cells become filled with numerous vacuoles of different sizes and configuration. At the third statge of morphologoical degradation, cell trans

[Cellular interactions in the intracellular parasitism of cryptosporidia. I. The effect of Cryptosporidium parvum on the phosphatase activity in the small intestine enterocytes of experimentally infected newborn rat pups]. / Kletochnye vzaimodeistviia pri vnutrikletochnom parazitirovanii kriptosporidii. I. Vliianie kriptosporidii Cryptosporidium parvum na fosfataznuiu aktivnost' v énterotsitakh tonkoi kishki éksperimental'no zarazhennykh novorozhdennykh krysiat.

Cytochemical methods for detection of non-specific phosphatases were employed at the light microscope level for identification of enzymatic activity in the small intestine of new-born rats (6--11 days old), both infected and non-infected with the intestinal coccidium Cryptosporidium parvum. In the new-born rats, the level of alkaline and especially acid phosphatase is originally very low, suggesting their insignificant involvement in digestion processes in suckling animals compared to rats of older age (3 month old). However, a heavy colonization of the brush border of the intestinal villi of the new-born rats with cryptosporidia results in obvious inactivation of phosphatases in the infected enterocytes, in contrast to the neighbouring parasite-free host cells. The general picture of metabolic interaction between cells of a unicellular parasite (C. parvum) and those of its metazoan host (rat) much resembles that observed in the course of Elmeria spp. infection, but differs from that induced by Toxoplasma gondii endogenous stages in the cat intestine. Details of cell interaction with intracellular parasitism need additional studies at the ultrastructural level.

[One of the possible ways of propagation of the unicellular parasites Sarcocystis muris in the musculature of the intermediate host]. / Odin iz vozmozhnykh putei rasprostraneniia odnokletochnykh parazitov Sarcocystis muris v muskulature promezhutochnogo khozaina.

20 laboratory mice (Mus musculus) were fed each a single dose of 20,000 Sarcocystis muris sporocysts to be then sacrificed 1, 2.5, 4, 6 and 10 months following infection (p.i.). A visual infection of the murine corps demonstrated that the number of sarcocysts per animal increased regularly as the time of infection was progressing, being eventually higher after 6 and 10 months p.i. than within 1-4 months p.i. This phenomenon was poorly understood from the knowledge that the tissue cysts (sarcocysts) are able to increase in size, rather than in number, and that the original number of sarcocysts largely depends on the number of precystic merozoites available. In our experiments, each of 20 mice was fed an equal number of sporocysts, and thus the number of precystic merozoites ought to be expected also more or less equal. EM investigation of murine skeletal muscles 6 and 10 months p.i. revealed, along with numerous normal sarcocysts, the presence of some separate, individual zoites, both within and outside the muscle fibre, in the endomysium. Besides, a colony of zoites, living freely without any visible common wall, was detected within a muscle fibre adjacent to another one, containing a sarcocyst of normal structure. These zoites may have originated from one or more sarcocysts, whose cyst walls were spontaneously broken, time after another, and thus led the cyst cells go out. These discharged zoites could either perish, being enzymatically degraded, or penetrate the neighbouring muscle fibres to proceed their further development. The colony making zoites were confined to two cell types only: the intermediate cells and the merozoites (gamonts). No metrocytes were recognized due, presumably, to inability of these little differentiated cells, devoid of penetrative organelles, to invade the host muscle cell. The colony of zoites turned out to be a developing population of live cells, able to destroy progressively the harbouring muscle fibre, except its basal membrane and sarcolemma. It does not seem unlikely that the outer coverings of the infected cell could be transformed eventually into a cyst wall to make, thus, a new sarcocyst. The above phenomena have never been found in murine muscles earlier than 6 months p.i. Although these facts are few and far between, they may prompt a possible mechanism of sarcocyst increase in number, in the intermediate host with age, even without any additional sporocyst contamination.

[The effect of coccidia of the genus Sarcocystis on the morphofunctional organization of the skeletal musculature in experimentally infected mice. I. The muscle fiber]. / Vliianie koktsidii roda Sarcocystis na morfofunktsional'nuiu organizatsiiu skeletnoi muskulatury éksperimental'no zarazhennykh myshei. I. Myshechnoe volokno.

At the ultrastructural level, the cellular response of skeletal muscles on developing Sarcocystis muris sarcocysts has been followed in mice at different times after sporocyst feeding, i.e. in 1, 2.5, 6 and 10 months, resp. The developing cyst creates a progressive degeneration of the infected muscle cell that involves organelle disorganization and formation of numerous vacuoles in the cytoplasm as a consequence of cell edema. Products of the host cell degradation, shaped as fibrillar-granular structures, are seen to find their way to the cyst wall outgrowings, where they become denser and on being covered with membranes appear eventually in the sarcocyst ground substance. Later on, the membranes around the granules disappear. In the course of its development, the sarcocyst totally destroys not only the harbouring muscle cell and the nearest connective tissue elements of the endomysium, but also the previously intact neighbouring cells. The involvement of some proteolytic enzymes in this process is suggested.

[Cytochemical study of various stages of life cycle of Toxoplasma gondii. 11. oxidation-reduction enzymes in the parasites during developmental stages in cat's intestines]. / Tsitokhimicheskoe issledovanie raznykh stadii zhiznennogo tsikla Toxoplasma gondii. 11. Fermenty okisleniia-vosstanovleniia v parazitakh na stadiiakh razvitiia iz kishechnika koshki.

Dehydrogenases of glycolysis, Krebs' cycle and pentose phosphate shunt were investigated in the intestinal stages of T. gondii. The "oval stages" appeared to display the activity of all the enzymes studied differing in this from merozoites and macrogametocytes. The macrogametocytes displayed very low, if any, activity of the enzymes studied, even the mature parasites. Immediately after fertilization, sharp shifts were observed in the oxidative metabolism of the zygote: from very low or negative it became moderate to strong. This may be suggestive of the changes in metabolic requirements of the zygote which is no longer an intracellular parasite. In this respect macrogametocytes and zygotes of Toxoplasma resemble the corresponding stages of chicken and rabbit intestinal coccidia of the genus Eimeria.

[Cytochemical study of various stages of life cycle of Toxoplasma gondii. 10. Phosphatases in the parasites during developmental stages in cat's intestines]. / Tsitokhimicheskoe essledovanie raznykh stadii zhiznennogo tsikla Toxoplasma gondii. 10. Fosfatazy v parazitakh na stadiiakh razvitiia iz kishechnika koshki.

Several methods of acid and alkaline phosphatese and ATPase detection using both natural and artificial substrates were applied to the intestinal stages of Toxoplasma gondii with negative results to reveal enzymatic activity in all the stages except the microgametocyte. Possible explanation of this unexpected phenomenon is discussed taking into account host-parasite relationships with intestinal stages of Toxoplasma and with coccidia in general.

[Cytochemical study of the different stages in the life cycle of Toxoplasma gondii. IX. The polysaccharides and lipids in the parasites at developmental stages from the cat intestine]. / Tsitokhimicheskoe issledovanie raznykh stadii zhiznennogo tsikla Toxoplasma gondii. IX. Polisakharidy i lipidy v parazitakh na stadiiakh razvitiia iz kishechnika koshki.

Amylopectin was detected in all the stages examined. In the oval stages the minute granules of PAS-positive material were seen in the cytoplasm when examined on fresh-frozen sections. In merozoites, amylopectin was more conspicuous with maturation. The residual body of microgametocytes contain large amounts of amylopectin; no polysaccharide was visualized in microgamete bodies. Amylopectin was most abundant in macrogametocytes and zygotes. However, no peripheral position of PAS-positive "plastic granules" (wall-forming bodies), so characteristic of other coccidia and revealed by the electron microscopy for T. gondii macrogametocytes, was seen. Acid mucopolysaccharides in the macrogametocyte were detected in the central zone, leaving the periphery of the cell unstained. Very small, if any, amounts of lipids were detected in asexual stages of T. gondii. Unlike, large accumulation of lipid droplets were seen in growing macrogametocytes suggesting the involvement of lipids along with amylopectin in the metabolism of oocysts later discharged from the host body.