An Unusual Pathway of Mitoptosis Found in Ehrlich Carcinoma Cells.

An integrated microscopic study of the destruction of mouse Ehrlich ascites carcinoma (EAC) cells under starvation conditions has been carried out. It has been found that, in addition to apoptosis, necrosis, and apoptotic necrosis, already known for EAC, cell destruction can also occur through mitochondrial autolysis, which is proposed to be considered a new kind of mitoptosis. A mitoptosis in EAC is characterized by the appearance of many autolyzing mitochondria, the fusion of which leads to rupture of the cell membrane and the ejection of the nucleus from the cell. It is assumed that the polymorphism of EAC destruction patterns is explained by the different physiological state of the cells, which determines the "choice" of the cell death mechanism. This situation poses a challenge for researchers to develop complex inducers with the ability to stimulate all possible types of cancer cell death.

[Ultrastructural study of spermatogenesis in silversides Oncorhynchus kisutch and cherry salmon O. masou (Salmonidae, Teleostei)].

Spermatogenesis in the silversides Oncorhynchus kisutch and cherry salmon O. masou, was investigated by transmission electron microscopy. It has been shown that male germ cells of both species had no difference in dimensional and ultrastructural parameters. The characteristic feature of spermatogonia was the presence of germ determinant substance, a cytoplasmic barker of sex line cells. Primary and secondary spermatocytes, as well as early spermatids were arranged in clusters consisted of synchronously developing cells. The spermiogenesis was peculiar in arising of electron-lucent vesicle which formed a structural complex with apical dense part of nuclear envelope. This complex has clear similarity with unformed spermatid acrosomes in many Metazoa and has been termed by the authors as an acrosome-like structure (AS). Disappearance of AS occurring at the final stage of the spermiogenesis allows considering AS as a temporary existing structure recapitulating the ancestral morphotype of salmonid sperm. Spermatozoa of both species are typical acrosome lacking cells which are characteristic of many representatives of Teleostei having external fertilization.

THE OOGONIA OF MACROALGA UNDARIA PINNATIFIDA ARE ALKALINE-PHOSPHATASE POSITIVE AND CONTAIN GERMINAL BODY-LIKE STRUCTURES(1).

It was observed that in the female gametophyte of Undaria pinnatifida (Harv.) Suringar (Phaeophyta, Laminariales) gametangial initials and maturing oogonia demonstrated different levels of alkaline-phosphatase activity (APA). The oogonia exhibited a higher level of APA than in its initials. Electron-dense granular ovoid structures ∼0.5-0.6 µm were present in the cytoplasm of oogonia. These inclusions were not membrane bound and do not appear to be associated with any particular organelles. The number of the inclusions was 1 to 2 in a single section of the cell. In essential details, the specific APA and subcellular germinal body-like structure of the developing female gamete in U. pinnatifida were very similar to those in metazoan oocytes.

[The ultrastructural patterns of germinal and yolk granules in oocytes and embryonic cells of the holothurian Apostichopus japonicus].

The yolk germinal granules in oocytes and embryonic cells of Apostichopus japonicus were studied by transmission electron microscopy. Analysis of the features of synthesis and utilization of yolk granules made it possible to reveal ultrastructural criteria to distinguish between granules of the forming and utilized yolk, and germinal granules. Based on these findings, the authors suppose that identification of germ plasm elements in oocytes and embryonic cells of A. japonicus is quite possible with ultrastructural analysis only, and does not require utilizing molecular markers.

[The ultrastructural patterns of germinal and yolk granules in oocytes and embryonic cells of the holothurian Apostichopus japonicus].

The yolk germinal granules in oocytes and embryonic cells of Apostichopus japonicus were studied by transmission electron microscopy. Analysis of the features of synthesis and utilization of yolk granules made it possible to reveal ultrastructural criteria to distinguish between granules of the forming and utilized yolk, and germinal granules. Based on these findings, the authors suppose that identification of germ plasm elements in oocytes and embryonic cells of A. japonicus is quite possible with ultrastructural analysis only, and does not require utilizing molecular markers.

[Problem of terminology in characteristics of spermatozoa of metazoa].

Difficulties in characterization of spermatozoa of the Metazoa are now related to insufficiency of the traditional terms "primitive spermatozoon", "modified spermatozoon", and "aberrant spermatozoon" introduced by G. Retzius and A. Franzen for description of intermediate forms discovered in the 20th century. In this respect, some authors propose to reject the Retzius' and Franzen's terms and turn to the terminological system of D. Rouse and B. Jamieson, the terms of which ("ectaquaspermatosoa", "entaquaspermatozoa", and "introspermatozoa") determine specific features of insemination, but do not reflect the structure of spermatozoa. The assertion of "helplessness" of the traditional structural Retzius' and Franzen's terms is unfounded. Their preservation is desirable if one wishes to preserve the comparative-morphological approach to the characterization of male gametes of the Metazoa. The terms "primitive spermatozoon", "modified spermatozoon", and "aberrant spermatozoon" will become more universal if the method of their combined utilization is applied.

[Comparative studies of follicle cells in testes of Glyptocephalus stelleri and Pleuronectes pinnifasciatus (Teleostei, Pleuronectidae)].

Accessory cells were studied in early spermatogenesis of flatfishes Glyptocephalus stelleri and Pleuronectes pinnifasciatus using transmission electron microscopy. The morphological organization of accessory cells in G. stelleri was similar to that of Sertoli cells. In P. pinnifasciatus, these cells had morphological organization, which had not been previously described.

[A comparative study of sperm postspawning destruction in flatfishes Hippoglossoides (Cleisthenes) herzensteini and Hippoglossoides dubius (Teleostei, Pleuronectidae)]. / Sravnitel'noe issledovanie postnerestovoi destruktsii spermatozoidov u kambalovykh ryb Hippoglossoides (Cleisthenes) herzensteini i Hoppoglossoides debius (Teleostei, Pleuronectidae).

Ultrastructural aspects of sperm destruction patterns were offered as additional cytological parameters for evaluation of the genus affinity of flatfishes Hippoglossoides dubius and Cleisthenes herzensteini. At the beginning of spermatozoan destruction, cell membrane in both species was found swollen, besides, discontinuity of membranes was observed, and membraneous parts were seen separating from sparmatozoa. We observed the ability of separated membraneous parts to aggregate to twisting conglomerates that wind round the objects of destruction. In H. dubius the membraneous conglomerates wound round spermatozoa, and after that such spermatozoa were phagocyted by follicular cells. In C. herzensteini, the membraneous conglomerates grasped the particles of destructed spermatozoa: the formed residual bodies were collected in the gonad lumen but not phagocyted by follicular cells. The expressiveness of the differences found in the pattern of sperm destruction is so considerable that, in the authors' opinion, these data are to supplement a list of criteria making reasonable reconsideration of the taxonomic status of C. herzensteini: its belonging to the genus Hippoglossoides, and establishing of the genus Cleisthenes as an independent rank.

An ultrastructural study of phagocytosis and shrinkage in nutritive phagocytes of the sea urchin Anthocidaris crassispina.

The ultrastructural mechanisms of waste-sperm phagocytosis and postspawning shrinkage were studied for accessory cells (nutritive phagocytes; NPs) of the sea urchin Anthocidaris crassispina. Sperm cells were phagocytosed by NPs; they penetrated into the cytoplasm of the NPs inside heterophagosomes formed by an invagination of the cell membrane. Single-sperm-containing heterophagosomes aggregated to form large multisperm heterophagosomes that were accompanied by cytoplasmic vesicles and lipids. Two types of vesicle, viz., Golgi-complex-derived electron-dense vesicles ("zymogen granules") and smooth-endoplasmic-reticulum-derived electron-lucent vesicles, were incorporated within multisperm heterophagosomes. Completed multisperm heterophagosomes were transformed into electron-dense remnant bodies, the content of which underwent destruction, resulting in "empty" vacuoles inside the remnant body. The "empty" vacuoles were then compressed by the surrounding cytoplasm. Shrinkage of NPs occurred upon completion of sperm degeneration in gonad tubules. This process was undertaken by structures termed cell-size-reducing autolysosomes, which performed two types of autolysis, and resulted in the formation of "cheese-hole"-like vacuoles in the cytoplasm of NPs. Subsequent cytoplasmic compression of these vacuoles was required for the reduction in size of NPs, an essential event for remodeling the cell for the next gametogenetic cycle.

Reproductive impairment of sea urchin upon chronic exposure to cadmium. Part II: Effects on sperm development.

Chronic pollution may impair the reproductive success of adult organisms through a decrease in the quality of gametes. Our parallel study on gamete quality, showed that male sea urchins were more sensitive than the females towards cadmium pollution. The effects of chronic exposure to 0.01 and 1 ppm Cd2+ on sperm development of the sea urchin Anthocidaris crassispina were studied. Despite the fact that no significant change in gonad index was observed when sea urchins were exposed to both levels of Cd2+ for 4 weeks, deposition of electron-dense materials was conspicuous at the wall and intracellular space of male gonads. Apparent cytological alterations were observed in sperm cells, including changes in morphology of nuage in spermatogonia. The discrete, granular bodies of nuage were replaced by a large electron-dense body. Spermatozoa with short, incomplete 'broken' tails (scanning electron microscope observation) or tails of spermatids/spermatozoa with extraordinary electron-density (transmission electron microscope observation) were more abundant in gonads exposed to both levels of Cd2+. Mitochondrial cristae deformation was observed for sperm cells at all stages of development. Sperm plasma membrane also became more convoluted but acrosome remained intact. The observed cytological distortion of sperm tails and mitochondria/midpiece could help to explain the decline in motility as well as poor perseverance in sperm produced by sea urchins exposed to cadmium observed in our earlier study.

Ultrastructure of the spermatozoa of five species of South African bivalves (Mollusca), and an examination of early spermatogenesis.

Transmission electron microscopy of the spermatozoa of five species from three families of bivalves has shown that each species has a sperm with unique morphology. However, the morphology of the acrosomes of each species is typical of the subclass of bivalve to which they belong. An examination of spermatogenesis in the five species, along with a re-examination of material from six other species of bivalves, has revealed that pre-spermiogenic cells possess flagella. In addition, acrosome formation begins in the spermatocytes with the formation of proacrosomal vesicles in the Golgi body. During spermiogenesis the proacrosomal vesicles coalesce at the presumptive posterior of the spermatid, with a larger vesicle produced by the Golgi body. The single acrosomal vesicle eventually migrates to the anterior of the spermatid where it assumes its mature form. © 1994 Wiley-Liss, Inc.