Cell ultrastructure in the pygmy shrew

Kalashnikova, M. M.; Смирнова, О. В.

doi:10.1007/bf00840629

Cited by 2 publications

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“…The release of cytosegresomes into both capillaries and sinusoids speeds up the removal of undigested metabolic products from the HCs. The open sinusoids and the presence of erythrocytes even in the smallest of them are indications that each HC is well supplied with blood and oxygen and that the metabolic activity of the liver is high, which agrees with our physiological data pointing to a high level of oxygen consumption by the least shrew [10].…”

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confidence: 90%

“…HCs of rats that had been exercising on a treadmill were found to have markedly increased numbers of mitochondria and mitochondrial cristae [ 11], comparable to those observed in the normally highly mobile least shrew [10]. Similarly, when rats, which do not normally absorb concentrated sucrose solutions in large amounts, were experimentally compelled to metabolize sucrose at a high rate, they "packed" it into vacuoles [27] in the same way as is normally done by American manatees and musk rats [8,9].…”

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confidence: 70%

“…However, whereas the release of cytosegresomes into sinusoids in fish may be regarded as an adaptive response developed because the number of bile capillaries is small, the occurrence of this phenomenon in the shrew can probably be explained by the very high metabolic rates resulting in the death of some organelles, so that the cells strive to free themselves from cytosegresomes as soon as possible by removing them via both bile capillaries and sinusoids [10].…”

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confidence: 99%

“…Manifestations of adaptive responses in the liver of the least shrew (a very small animal that is on the move much of the day in search of food, which it consumes in quantities 2 to 4 times its body weight) are an abundance of mitochondria with very large numbers of cristae, broad, open sinusoids containing erythrocytes in their lumens, and the release of cytosegresomes from HCs not only into bile capillaries but also into sinusoids, where they undergo phagocytosis by Kupffer's cells and macrophages [10]. The abundance of mitochondria with numerous cristae in the shrew HCs testifies to a high level of energy metabolism in these cells.…”

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confidence: 99%

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Liver cells in a comparative morphological series of animals: Ultrastructural features and their significance

Kalashnikova

1996

Bull Exp Biol Med

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A detailed ultrastructural analysis of liver cells in a comparative morphological series of animals from various classes has provided insight into how liver structure was perfected in the course of evolution. Specific features of the adaptive responses acquired by hepatocytes in different animal classes for maximizing their many functions in the framework of the existing organ structure are identified. It is shown that the adaptations found in lower animals also normally occur in more highly organized animals, and that the same adaptations developed by hepatocytes during phylogeny are used in responding to various influences exerted upon the organism.Key Words: hepatocyte; ultrastructure; adaptations; phylogeny Perusal of the relatively large body of published ultrastructural data on liver cells of fish, amphibians, reptiles, birds, and mammals [16][17][18][19][20][21][22][23][24][25][26][27] shows that although liver cells in animals of different classes share a common set of organelles, these cells vary in structure both between and within classes. However, the specific features of their fine structure have rarely been discussed.Drawing on the reported evidence and on our own numerous findings from studies of liver cells in various animal classes, we propose here to analyze comparative ultrastructural features of liver cells with particular reference to the adaptations these cells have developed. The basic elements we have taken for comparison are the hepatocyte (HC), bile capillary, sinusoidal cell, and sinusoid, i.e., the elements which, by combining in different ways in the livers of animals Laboratory of Evolutionary Histology, A. N. Severtsov Institute of Evolutionary Animal Morphology and Ecology, Russian Academy of Sciences, Moscow from different classes, make up this complex multifunctional organ. Analysis of fiver cell ultrastructure in a comparative morphological series of animals may be expected to shed light on how the structure of such a complex and perfect organ as the mammalian fiver was refined and improved in the course of phylogeny and to identify the attributes with which liver cells of different animals have been endowed for maximizing their many functions in the framework of the organ structure existing in particular animals.Livers

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Liver cells in a comparative morphological series of animals: Ultrastructural features and their significance

Kalashnikova

1996

Bull Exp Biol Med

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“…The ultrastructure of the majority of hepatocytes of both species of rodents captured in the Tyumentsevo district was in general the same as in other small rodents [2,5]. Cisternae of granular ER, polymorphous mitochondria, and vesicles of smooth ER were clearly seen in moderately dense cytoplasm ( Fig.…”

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confidence: 95%

Ultrastructural stereological analysis of the liver of Muridae from regions with various levels of anthropogenic pollution

1996

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Ultrastructural stereological analysis revealed the fundamental reorganization of hepatocytes in Muridae from natural ecosystems exposed to anthropogenic factors. An appreciable decrease of the volume density of mitochondria and granular endoplasmic reticulum was associated with a many-fold increase of the volume density of glycogen. The detected hepatocyte glycogenosis was characterized by a redistribution of organelles and the formation of large depots of glycogen with reduced electron density.Key Words: anthropogenic pollution; Muridae; hepatocytes; ultrastructure; stereology Analysis of the fine structural changes and identification of the patterns of intracellular reorganization under novel ecological conditions play an important role in the comprehensive assessment of the biological effects determined by exposure to technogenic factors. This is especially true for the biological effects caused by prolonged exposure to low-level industrial factors, which have recently become dominant in many natural regions [8]. However, these effects have been little studied from the viewpoint of both their phenomenology and the mechanisms of their development.This study was aimed at assessing the intracellular reorganization of hepatocytes of Muridae captured in two regions with different levels of anthropogenic pollution. MATERIALS AND METHODSLiver samples from 20 adult male common field mice (Apodemus sylvaticus) and 18 common voles (Microtus arvalis), captured in three regions of the Altai with different levels of pollution, were examined under an electron microscope. Two regions (Uglovskoe and Lokot') have been exposed to radionuclides for a long time as a result of nuclear tests at the Semipalatinsk testing grounds [6,11]. In addition, the soil in the Lokot' district is contaminated with heavy metal salts. The third district (Tyumentsevo) served as a control.For electron microscopy, liver specimens from the large lobe were fLxed in 4% paraformaldehyde in Millonig's buffer (pH 7.4), postfLxed in 1% osmium tetroxide, and after dehydration embedded in EponAraldite mixture. Ultrathin slices were made with an LKB III ultratome and after contrast staining with uranyl acetate and lead citrate examined under a JEM 100C electron microscope at an accelerating voltage of 80 kV.

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Cell ultrastructure in the pygmy shrew

Cited by 2 publications

References 2 publications

Liver cells in a comparative morphological series of animals: Ultrastructural features and their significance

Liver cells in a comparative morphological series of animals: Ultrastructural features and their significance

Ultrastructural stereological analysis of the liver of Muridae from regions with various levels of anthropogenic pollution

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