Immunocytochemical demonstration of taurine in the retina and pineal organ of the pigeon.

Taurine-like immunoreactivity (TLI) is found in the pigeon retina at high levels within cones, in select cells of the inner nuclear layer and in sublaminae of the inner plexiform layer. At the ultrastructural level a high density of immuno-gold particles in visualized in the ellipsoid, but not in the paraboloid area of the inner segment. It is present in perikarya and the presynaptic endings of cones, but not in postsynaptic cell processes. The immuno-gold particles are not associated directly with the synaptic vesicles. In the pineal organ TLI was confined to the so-called dark pinealocytes which are surrounded by only family stained light pinealocytes. Clusters of protein A-gold particles are located in the ergastoplasm between polyribosomes adjacent to fibrous proteins and in chains along filamentous structures. Granules, vesicles and membrane whorls, which originate from modified cilia remain unlabeled. The results are discussed on the basis of previous findings; a direct or indirect functional relationship of taurine to ATP-dependent processes is suggested.

Immunocytochemical localization of taurine and glial fibrillary acidic protein in human optic nerve.

Taurine immunoreactivity (IR) in 1-microns sections of glutaraldehyde-fixed human optic nerve was observed using light microscopy and an antibody raised in rabbit to taurine conjugated to bovine serum albumin. Throughout the nerve, taurine-IR was prominent in glial cells, in their perinuclear regions, and in their numerous branching processes, some of which extended to the pial septa. The peripheral glial mantle (glia limitans) was densely stained, whereas axons and the pial septa showed relatively little or no taurine-IR. Immunoreactivity for glial fibrillary acidic protein (GFAP), and astrocyte-specific marker, was evaluated on adjacent sections. The pattern of GFAP-IR was highly similar to that for taurine, suggesting that a subset of taurine-immunoreactive glial cells are optic nerve astrocytes. To our knowledge, this is the first localization of taurine and GFAP in human optic nerve.

Immunocytochemical localization of taurine within glial cells in the optic nerve of adult albino rats.

Taurine immunoreactivity in one micron sections of the adult rat optic nerve was observed using light microscopy. Prominent staining was seen in glial cell somata in the perinuclear region and in their processes throughout the nerve, particularly in endfeet on capillaries and in the peripheral basal lamina (glia limitans). Axons and blood vessels showed relatively little or no staining in the mature nerve. The pattern of glial fibrillary acidic protein immunoreactivity on subsequent sections was similar in many respects to that of taurine, suggesting that a sub-population of taurine immunoreactive glial cells are optic nerve astrocytes.

Immunocytochemical localization of taurine in the mammalian retina.

This paper describes the first demonstration of taurine-like immunoreactivity in the mammalian retina using an antiserum raised in rabbits. In rat, cat and guinea pig retina a peroxidase-antiperoxidase immunocytochemical technique showed high levels of taurine immunostaining in photoreceptor inner segments and synaptic terminals, in subpopulations of amacrine and bipolar somata and their synaptic processes in the inner plexiform layer, including numerous large terminals near and on ganglion cell somata. Using the Protein A-gold technique for ultrastructural studies in the rat, the presence of synaptic ribbons confirmed that some of these taurine-containing terminals were from bipolar cells. Lower levels of immunostaining were seen in the pigment epithelium and distal parts of glial cells.

Maternal age and lifespan do not influence longevity in the rotifer Asplanchna brightwelli.

An analysis of the mean lifespans among the progeny of the viviparous rotifer Asplanchna brightwelli produced during four generations has revealed that longevity of the offspring is not affected by maternal age of the parent or by the parent's lifespan. The production of viable offspring at any time during the parent's reproductive period may be of importance in assuring the continuity of clones of this short-lived rotifer species.

The effect of dietary restriction on cell division potential, DNA content and enzyme levels in the rotifer Asplanchna brightwelli.

Dietary restriction in the rotifer Asplanchna brightwelli, carried out by lengthening the interval between feedings, causes an increase both in mean lifespan and in the length of the reproductive period. In the present study, we found that the rate of nuclear division in the gastric glands and vitellarium of the rotifer, as determined by daily nuclear counts, was retarded by dietary restriction. Spectro-fluorimetric measurements show that total DNA content remains constant from the beginning to the end of the lifespan, and is unaffected by dietary restriction. Lactic dehydrogenase and malic dehydrogenase activities were also measured throughout the lifespan of the rotifer, and were not affected by dietary restriction.

The effect of temperature and of dietary restriction on lifespan and reproduction in the rotifer Asplanchna brightwelli.

In this study, the effects of different environmental temperatures and of dietary restriction on the lifespan, reproductive cycle, and fecundity of the rotifer Asplanchna brightwelli were examined. When temperature effects were analyzed, it was observed that the mean lifespan and the times at which the reproductive cycle started and ended all increased as environmental temperatures decreased. When dietary restriction was imposed by increasing the interval between feeding times from 12 to 36 hours, there was an increase both in the mean lifespan and in the length of the reproductive period in this rotifer.