International Review of Cytology-a Survey of Cell Biology 

About: International Review of Cytology-a Survey of Cell Biology is an academic journal. The journal publishes majorly in the area(s): Population & Gene. Over the lifetime, 1783 publications have been published receiving 165548 citations.

Cell death : the significance of apoptosis

Abstract: Publisher Summary The classification of cell death can be based on morphological or biochemical criteria or on the circumstances of its occurrence. Currently, irreversible structural alteration provides the only unequivocal evidence of death; biochemical indicators of cell death that are universally applicable have to be precisely defined and studies of cell function or of reproductive capacity do not necessarily differentiate between death and dormant states from which recovery may be possible. It has also proved feasible to categorize most if not all dying cells into one or the other of two discrete and distinctive patterns of morphological change, which have, generally, been found to occur under disparate but individually characteristic circumstances. One of these patterns is the swelling proceeding to rupture of plasma and organelle membranes and dissolution of organized structure—termed “coagulative necrosis.” It results from injury by agents, such as toxins and ischemia, affects cells in groups rather than singly, and evokes exudative inflammation when it develops in vivo. The other morphological pattern is characterized by condensation of the cell with maintenance of organelle integrity and the formation of surface protuberances that separate as membrane-bounded globules; in tissues, these are phagocytosed and digested by resident cells, there being no associated inflammation.

Stereological principles for morphometry in electron microscopic cytology.

Abstract: Publisher Summary This chapter focuses on the stereological principles for morphometry in electron microscopic cytology. Morphometry of the cell serves the purpose of furnishing quantitative information on cellular fine structure with the aim of allowing quantitative correlation of biochemical or physiological data with morphological data obtained on structurally intact cells. the morphometric approach to cytology is not a purpose in itself, although admirable dimensional equilibria can be revealed which satisfy the esthetic needs. It is a means that serves the aim of structure-function correlation and derives its justification from the recognition that all orderly function must have an organized structural basis of a size that is adequate but not excessive. The chapter emphasizes on the possibilities of applying morphometric methods to correlative cell biology.

Animal mitochondrial DNA: structure and evolution.

Abstract: Publisher Summary This chapter describes structural features and evolution of metazoan mitochondrial DNA (mtDNA) molecules. Throughout the evolution of metazoa, gene content of mitochondria-genomes is highly conserved, as has the close packing of genes. Most of the occasional sequence expansions that have occurred, by way of either repeated or noncoding unique sequences, are found in the control or putative control region, rather than being dispersed between genes. Of the 13 open reading frames recognized in the human mtDNA molecules, four (COI, COII, COIII, and Cyt b) are originally identified in regard to the proteins they encode, from similarities of their predicted amino acid sequences to known amino acid sequences of bovine proteins, and predicted amino acid sequences of yeast mt-protein genes. Among mtDNAs of vertebrates and higher invertebrates, there are genes that overlap. Some overlaps are among the 3′ ends of two genes that are encoded in opposite strands of the molecule. The extent of size reduction within metazoan mitochondrial-transfer RNA (mt-tRNA) gene sets strongly correlates with the degree to which the more variable secondary structure element-forming regions of mt-rRNA genes are lost.

Structure and function of intercellular junctions.

Abstract: Publisher Summary Intercellular junctions are specialized regions of contact between the apposed plasma membranes of adjacent cells, and recent evidence suggests that they are essential for the development of multicellular organisms. They provide the structural means for groups of cells to interact in certain defined ways, and thereby enable them to create structures of higher order. This chapter reviews the morphological information on intercellular junctions derived from thin-sectioning, negative staining and freeze-cleave techniques, as well as from x-ray diffraction and biochemical investigations, and correlates the structural parameters with known or proposed physiological functions. The membrane structure of intercellular junctions is described. Membrane proteins can be divided into two groups: peripheral and integral. Peripheral membrane proteins are believed to be associated with the membrane surface, based on the observation that they are held to the membrane by rather weak noncovalent interactions, and are not strongly associated with membrane lipids. Only mild treatments, such as an increase in ionic strength of the medium or the addition of a chelating agent, are needed to dissociate them molecularly intact from the membrane. Furthermore, in the dissociated state they are relatively soluble in neutral aqueous buffers. In contrast, integral membrane proteins appear much more strongly bound to the lipid matrix, since they can be dissociated from the latter only by drastic treatments with chemicals such as detergents, protein denaturants, and organic solvents. The diversity in structure and function of intercellular junctions offers an exciting field for future research in which morphologists, physiologists, and biochemists should be able to make significant contributions to the knowledge of how individual cells interact to form structures of higher order.

Development of Follicles in the Mammalian Ovary

Abstract: Publisher Summary This chapter discusses the development of follicles in the mammalian ovary. The unresolved issues in follicular development are focused. Folliculogenesis culminates in the production of fully ripe, preovulatory follicles visible to the naked eye as large bulges on the surface of the ovary. Each ripe follicle contains thousands of highly differentiated cells. This complex, functional miniature organ arises from the handful of cells that constitute a simple primordial follicle, a structure so small that it is invisible at the lower magnifications of a light microscope. All regulatory influences can only permit or prevent cells from completing the full maturation process; they cannot change the course of differentiation. A plethora of modulating influences act as permissive inducers, impeding or propelling the committed follicular cells through the process of clonal expansion. As each follicle progresses through its program of limited clonal expansion and maturation, its cells proliferate more and more rapidly. With every passing generation, the proliferative potential of the granulosa and theca cells continues to diminish, while the state of maturation increases.