Ultrastructural traits of apoptosis.

This review summarizes original and literature data on changes in the ultrastructure of major cell organelles during apoptosis obtained by transmission electron microscopy. Organelles that make the most crucial contribution to the initiation of apoptosis: plasma membrane, mitochondria, proteasomes, Golgi apparatus, and endoplasmic reticulum, were of our prime attention. The nucleus and cytoskeleton that undergo essential changes, were considered as well.

Ultrastructural analysis of human leukemia U-937 cells after apoptosis induction: Localization of proteasomes and perichromatin fibers.

We studied the ultrastructure of human histiocytic lymphoma U-937cells after apoptosis induction with two external agents, hypertonic shock and etoposide. Appearance of aggregates of particles of nuclear origin within the nuclei and cytoplasm of the induced cells was the first and the most prominent morphological sign of apoptosis. These aggregates were not coated by a membrane, had variable shape, density and size.

The identification and characterization of IbpA, a novel α-crystallin-type heat shock protein from mycoplasma.

α-Crystallin-type small heat shock proteins (sHsps) are expressed in many bacteria, animals, plants, and archaea. Among mycoplasmas (Mollicutes), predicted sHsp homologues so far were found only in the Acholeplasmataceae family. In this report, we describe the cloning and functional characterization of a novel sHsp orthologue, IbpA protein, present in Acholeplasma laidlawii.

Immunoelectron microscopic study of BASP1 and MARCKS location in the early and late rat spermatids.

Immunoelectron microscopy was used to locate the proteins BASP1 and MARCKS in the post-meiotic spermatids of male rat testis. It was shown that in early spermatids, BASP1 and MARCKS accumulate in chromatoid bodies, which are characteristic organelles for these cells. During spermatogenesis, while the spermatid nucleus is still active, the chromatoid body periodically moves to the cell nucleus and absorbs the precursors of definite mRNAs and small RNAs.

Analogs of the Golgi complex in microsporidia: structure and avesicular mechanisms of function.

Microsporidia are obligatory intracellular parasites, most species of which live in the host cell cytosol. They synthesize and then transport secretory proteins from the endoplasmic reticulum to the plasma membrane for formation of the spore wall and the polar tube for cell invasion. However, microsporidia do not have a typical Golgi complex.