Neuron Segmentation With High-Level Biological Priors.

We present a novel approach to the problem of neuron segmentation in image volumes acquired by an electron microscopy. Existing methods, such as agglomerative or correlation clustering, rely solely on boundary evidence and have problems where such an evidence is lacking (e.g., incomplete staining) or ambiguous (e.g., co-located cell and mitochondria membranes). We investigate if these difficulties can be overcome by means of sparse region appearance cues that differentiate between pre- and postsynaptic neuron segments in mammalian neural tissue. We combine these cues with the traditional boundary evidence in the asymmetric multiway cut (AMWC) model, which simultaneously solves the partitioning and the semantic region labeling problems. We show that AMWC problems over superpixel graphs can be solved to global optimality with a cutting plane approach, and that the introduction of semantic class priors leads to significantly better segmentations.

[Neonatal infection with Salmonella apapa after contact with a reptile in the home]. / Neugeborenensepsis durch Salmonella apapa nach Reptilienkontakt im Haushalt.

Salmonella apapa is transmitted by reptiles, e.g., bearded dragons. To date only few cases of S. apapa-related human infections have been reported. Because the bacteria are transmitted through the feces of animals or direct contact with low infection doses, infection in early infancy is possible. We report an 18-day-old newborn with sepsis caused by Salmonella apapa. Salmonella apapa was isolated from the feces of a bearded dragon living along with the family.

[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.

[Self-organizing neural networks for automatic detection and classification of contrast (media) enhancement of lesions in dynamic MR-mammography]. / Selbstorganisierende neuronale Netze zur automatischen Detektion und Klassifikation von Kontrast(mittel)-verstärkten Läsionen in der dynamischen MR-Mammographie.

PURPOSE: Investigation and statistical evaluation of "Self-Organizing Maps," a special type of neural networks in the field of artificial intelligence, classifying contrast enhancing lesions in dynamic MR-mammography. MATERIAL AND METHODS: 176 investigations with proven histology after core biopsy or operation were randomly divided into two groups. Several Self-Organizing Maps were trained by investigations of the first group to detect and classify contrast enhancing lesions in dynamic MR-mammography. Each single pixel's signal/time curve of all patients within the second group was analyzed by the Self-Organizing Maps. The likelihood of malignancy was visualized by color overlays on the MR-images. At last assessment of contrast-enhancing lesions by each different network was rated visually and evaluated statistically. RESULTS: A well balanced neural network achieved a sensitivity of 90.5 % and a specificity of 72.2 % in predicting malignancy of 88 enhancing lesions. Detailed analysis of false-positive results revealed that every second fibroadenoma showed a "typical malignant" signal/time curve without any chance to differentiate between fibroadenomas and malignant tissue regarding contrast enhancement alone; but this special group of lesions was represented by a well-defined area of the Self-Organizing Map. DISCUSSION: Self-Organizing Maps are capable of classifying a dynamic signal/time curve as "typical benign" or "typical malignant." Therefore, they can be used as second opinion. In view of the now known localization of fibroadenomas enhancing like malignant tumors at the Self-Organizing Map, these lesions could be passed to further analysis by additional post-processing elements (e.g., based on T2-weighted series or morphology analysis) in the future.

[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.

[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.

[Cell response of rat liver parenchyma to the infection by the intestinal protozoan pathogen Cryptosporidium parvum (Sporozoa, Coccidia)]. / Reaktsiia kletok parenkhimy pecheni krys na zarazheniie kishechnym protozoinym patogenom Cryptosporidium parvum (Sporozoa, Coccidia).

In the present work, the authors' previous studies of a "distant action", exerted by an intestinal pathogen (Cryptosporidium parvum) on the liver of experimentally infected baby rats, were extended to include shifts in the quantity of glycogen, protein and nuclear DNA in the host liver at different degrees of infection. One of the outcomes of this work is the discovery of a very quick response of hepatocytes and a high sensitivity of rat liver to parasitic invasion even at a weak intensity of infection. 85-90 h after oocyst feeding to rats, glycogen quantity in their livers was 2.5 times lower that in the control. This suggests that the infected host liver worked under energetic starvation conditions. The proposed coefficients of general infection (I) and infection with intracellular stages (F) made it possible to distinguish between the total abundance of parasites in the host intestine during the whole period of infection, and the number of feeding intracellular stages available by the moment of autopsy. The glycogen amount in rat hepatocytes does not depend on I, and negatively correlates with F. Unlike, the protein content in hepatocytes positively correlates with I, being independent of F. Despite the obvious deficiency of amino acids in the infected rats, as a consequence of cryptosporidiosis-induced malabsorption, the protein synthesis in their hepatocytes was not at all inhibited but, on the contrary, much activated. This is a most characteristic feature of the distant action of C. parvum on the liver of parasitized host. With C. parvum infection, the share of polyploid hepatocytes does not correlate with either I, or F. However, compared to the control, the mean values of relative numbers of polyploid cells in weakly, moderately, and heavily infected animals (according to I values) were higher by 20, 100 and 100%, respectively. In hepatocyte nuclei of C. parvum infected rats, the total area of nucleoli increases almost by 30%. The above changes are discussed in terms of both the liver compensatory response to the existing pathology (diarrhea), and the host-parasite relationships. Studies into the distant action of an intestinal pathogen (C. parvum) on non-intestinal organs (liver) of the infected host may be qualified as a new and original approach to pathogenesis of protozoan infections (coccidioses sensu lato), to which young host specimens are known to be most susceptible.

Electronic g factor of hydrogenlike oxygen 16O7+.

We present an experimental value for the g factor of the electron bound in hydrogenlike oxygen, which is found to be g(expt)=2.000 047 025 4 (15)(44). The experiment was performed on a single 16O7+ ion stored in a Penning trap. For the first time, the expected line shape of the g-factor resonance is calculated which is essential for minimizing the systematic uncertainties. The measurement agrees within 1.1 sigma with the predicted theoretical value g(theory)=2.000 047 020 2 (6). It represents a stringent test of bound-state quantum electrodynamics to a 0.25% level. Assuming the validity of the underlying theory, a value for the electron mass is obtained: m(e)=0.000 548 579 909 6 (4) u. This value agrees with our earlier determination on and allows a combination of both values which is about 4 times more precise than the currently accepted one.

[Formation and diversity of parasitophorous vacuoles in parasitic protozoa. The Coccidia (Sporozoa, Apicomplexa)]. / Puti formirovaniia parazitofornykh vakuolei i ikh raznoobrazie u paraziticheskikh prosteishikh. Koktsidii (Sporozoa, Apicomplexa).

Data on parasitophorous vacuole (PV) formation in host cells (HC) harbouring different intracellular protozoan parasites have been reviewed and critically analysed, with special reference to the main representatives of the Coccidia. The vacuole membrane (PVM) is the interface between host and parasite, playing a role in nutrient acquisition by the parasite from the HC. The PV phenomenon is regarded as a generalized HC response to the introduction of alien bodies (microorganisms), which eventually reflects the evolutionary established host-parasite relationships at cellular, subcellular and molecular levels. Special attention has been paid to the existing morpho-functional diversity of the PVs within the same genera and species of parasites, and even at different stages of the parasite life cycle. The PVM is generally considered to derive from the HC plasmalemma, whose biochemical composition undergoes significant changes as the intravacuolar parasite grows. The original HC proteins are selectively excluded from the PVM, while those of the parasite are incorporated. As the result, the changed PVM becomes not fusigenic for HC lysosomes. For Toxoplasma gondii and other cyst-forming coccidia (Isospora, Sarcocystis), a definite correlation has been noticed between the extent of rhoptry and dense granule secrets released by a zoite during HC internalization, on the one hand, and the pattern of the PV that forms, on the other one. In T. gondii, tachyzoites, known to discharge abundant secrets, commonly force the development of PVs limited with a single unit membrane and equipped with a tubulovesicular network in the lumen. Unlike, bradyzoites known to be deficient in secretory materials trigger the formation of PVs with a three-membrane lining composed of the changed invaginated plasmalemma in addition to two membranes of endoplasmic reticulum. The two different types of PV harbour, respectively, exoenteric and enteric stages of T. gondii, the latter being confined to the cat intestine only. Unlike, all endogenous stages of the classic intestinal coccidia (Eimeria spp.) develop within PVs limited with a single membrane, with some invaginations extending into the PV lumen. Unusual PV patterns are characteristic of the extracytoplasmic eimerian coccidia (Cryptosporidium, Epieimeria) and adeleid haemogreagarines (Karyolysus). In cyst-forming coccidia, the PVM is actively involved in tissue cyst wall formation, thus protecting the encysted parasites from recognition by the host immune system. All this strongly suggests that the PV is far from being an indifferent membraneous vesicle containing a parasite, but represents a metabolically active compartment in infected cells. Since all the coccidia are obligate intracellular parasites, the mode of their intimate interaction with the HC, largely accomplished via the PV and its membrane, is vital for their survival as biological species.

[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.

[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.

[Morphofunctional changes in hepatocytes during the early postnatal development of rats experimentally infected with the intestinal protozoan pathogen, Cryptosporidium parvum (Coccidia, Sporozoa)]. / Morfofunktsional'nye izmeneniia pecheni v rannem postnatal'nom razvitii u krys, éksperimental'no zarazhennykh kishechnym protozoinym patogenom Cryptosporidium parvum (Coccidia, Sporozoa).

Morphofunctional changes in hepatocytes of 10-14-day old rats were followed in norm and after experimental infection with different doses of oocysts of Cryptosporidium parvum. The liver index (ratio between the liver and body masses) varied with the intensity of invasion on the background of slowing down up to the total cessation of animal growth rates, and all this obviously pointed to severe pathology. In the infected rats, some cytological indices were shifted compared to the norm: protein amount and the average number of genomes per hepatocyte were seen to increase, the normal ratio between cells with different ploidy levels being violated. The particular correlation analysis was employed to distinguish between the ontogenetic (animal growth related) and pathologic (related to the infection intensity) polyploidization and hypertrophy in hepatocytes. In 10-14-day old rats, the former is affected primarily by the increase in the share of multinuclear hepatocytes, whereas the latter is accomplished by the increase in the number of cells with polyploid nuclei (4c and 4c x 2 cells). In the heavily infected rats, the ontogenetic polyploidy was almost totally suppressed due, presumably, to their growth rate inhibition, the rise in hepatocyte ploidy resulting form the obvious pathological changes in the liver. In the infected rats, the ontogenetic hypertrophy of hepatic parenchymatous cells was not manifested, and the observed protein accumulation in hepatocytes also resulted from the pathological changes in the liver. It is obvious that changes in cell hypertrophy (protein content) may serve as a more susceptible tool that readily perceives the host's stress experienced due to the parasitic infection (cryptosporidiosis), than cell ploidy: the levels of the respective responses of these two parameters differing by 4 times. However, due to the known reversible nature of hypertrophy, it cannot be used for the aims of a long-term prediction about the future mode of liver functioning in the animal that survived cryptosporidiosis. Unlike, such a parameter as frequencies of hepatocytes with different ploidy levels is much more useful in this respect.

[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.

[Intracellular parasitism and sarcocystosis]. / Vnutrikletochnyi parazitizm i problema sarkotsistoza.

The obligatory heterogenous tissue cyst-forming coccidia of the genus Sarcystosis are regarded as an excellent example of specific coexistence of two organisms, i.e., the host and parasite. These parasitic protozoans are known as causative agents of the chronic, often life-threatening disease, sarcocystosis, which still cannot be effectively controlled. In Sarcocystis, the entire phase of asexual multiplication was transferred to the intermediate host. Of special interest is the parasite's ability to persist in this host at the stage of tissue cyst or sarcocyst. This is a giant meront, in which unidirectional development proceeds starting from a little differentiated metrocyte, through intermediate cells, and towards highly differentiated cyst merozoites (gamonts) unable to further divide. The life span of the sarcocyst depends, to a great extent, on self-regulation within the cyst itself and on relations between the cyst and its immediate environment. A totally new field of research into Sarcocystis was initiated by the discovery that the intracellular parasite damages both cyst harboring and intact muscle cells, apart from the adjacent connective and nervous tissue. The previously unknown cytopathological effects of sarcocysts have been described and characterized. The changes observed within and outside the sarcocysts have been analyzed in terms of general biological processes: proliferation, differentiation, and programmed cell death.

[Oocyst structure and problem of coccidian taxonomy]. / Struktura ootsist i voprosy sistematiki koktsidii.

A comparative ultrastructural study was made of both thin- and thick-walled oocysts of Cryptosporidium parvum. According to the authors' findings, all the oocysts in C. parvum should be considered as thin-walled, since their walls have been composed of a single membrane or of two, closely apposed membranes without any additional substance in between. Despite the presence of two types of wall-forming bodies (WFB) in the maturing macrogamete or zygote, there is no evidence of their involvement in oocyst wall formation. In this concern, the function and destiny of WFB in C. parvum oocysts still remain obscure. Similar structure of the oocysts wall was reported elsewhere for thin-walled oocysts of fish coccidia of the genera Goussia and Eimeria. In C. parvum, the "thick-walled" oocysts differ from oocysts with thin walls in the availability in the former of a single sporocyst. The sporocyst wall consists of two unequal layers: a thin outer layer and a thicker inner one, in which a characteristic suture line is occasionally seen. By this feature the thick-walled oocysts of C. parvum bear similarities with oocysts of the cyst-forming coccidia (Cystoisospora, Toxoplasma, Sarcocystis) and of the genus Goussia: in all these the valves making up the sporocyst wall are joint just along the suture line. The literary and the authors' own data make it possible to suppose that the suture detected in C. parvum oocysts is located in the sporocyst wall, joining its valves, rather than in the oocyst wall proper, known to be composed of one or two, closely apposed unit membranes. Again, the availability of a suture (or sutures) in the sporocyst hardly provides enough reason to relate C. parvum with either cyst-forming, or fish coccidia, since this structure itself may be of a convergency character, rather than of systematic value. This may be substantiated, at least in part, by the authors' previous findings (Beyer, Sidorenko, 1984) of a similar structure, originally referred to as a "slit channel", in the intraerythrocytic capsule around gamont stage of haemogregarines--the adeleid coccidia of the genus Karyolysus. The suture-like structure could have originated in the evolution independently in different groups of parasitic protozoa to serve eventually as a suitable mechanism for immediate separation of elements involved in protective formation harbouring different developmental stages, including, for example, sporozoites in the eimeriid coccidia, or gamonts in the adeleid coccidia.

[Further comment on the coccidian nature of cryptosporidia (Sporozoa: Apicomplexa)]. / Eshche raz o koktsidiinoi prirode kriptosporidii (Sporozoa: Apicomplexa).

The coccidian nature of the genus Cryptosporidium was undoubtedly accepted by Tyzzer who was the first to describe this sporozoan parasite in 1907. Electron microscopic studies made in 70-90s demonstrated the intracellular, although extracytoplasmic localization of Cryptosporidium spp. The pattern of Cryptosporidium life cycle fits well that of other intestinal homogeneous coccidian genera of the suborder Eimeriina: macro- and microgamonts develop independently, a microgamont gives rise to numerous male gametes, oocysts serving for parasite's spreading in the environment. Along with these characters, Cryptosporidium spp. demonstrate some secondary peculiarities (an endogenous phase of development in microvilli of epithelial surfaces, two morphofunctional types of oocysts, the smallest number of sporozoites per oocyst, a multi-membraneous "feeder" organelle etc.), which may be due presumably to their early acquisition of specialization in the course of evolution. The recent studies based on molecular sequence data (18S rRNA) applied to 8 eimeriid and isosporid coccidian genera (Morrison, Ellis, 1997), suggested that the subclass Coccidia (class, according to Morrison and Ellis) be considered monophylic if Cryptosporidium were excluded, and this genus was regarded as the sister group to the rest of the Apicomplexa, or as the sister to the suborder (class) Hematozoa within the Apicomplexa. Either of these placements of Cryptosporidium definitely conflicts with both the generally accepted taxonomic scheme by Levine (1982) and the phenotypically based phylogeny of the phylum Apicomplexa (Barta e. a., 1990). The author's opinion is that the differences between the examined eimeriid and isosporid coccidia, on the one hand, and Cryptosporidium, on the other hand, provided by molecular sequence data, may testify primarily to the well known morphofunctional dissimilarities between the compared organisms, rather than cast doubt on the coccidian nature of Cryptosporidium. Again, these data can hardly prove that Cryptosporidium does not belong to the coccidia. Thus, the modern molecular sequence data, despite their obvious scientific value, would make sense for phylogeny estimation only, if they are critically analysed and considered in combination with results of the relevant basic research.

High-accuracy measurement of the magnetic moment anomaly of the electron bound in hydrogenlike carbon.

We present a new experimental value for the magnetic moment of the electron bound in hydrogenlike carbon (12C5+): g(exp) = 2.001 041 596 (5). This is the most precise determination of an atomic g(J) factor so far. The experiment was carried out on a single 12C5+ ion stored in a Penning trap. The high accuracy was made possible by spatially separating the induction of spin flips and the analysis of the spin direction. The current theoretical value amounts to g(th) = 2.001 041 591 (7). Together experiment and theory test the bound-state QED contributions to the g(J) factor of a bound electron to a precision of 1%.