Background: The objective of the current study was to determine the effect of activation of injected oocytes with dithiothreitol on development of ovine embryos derived from in vitro-matured oocytes and intracytoplasmic sperm.The injected oocytes with non-treated sperm were activated with 1) ionomycin (Io) + 6-dimethylaminopurine (6-DMAP) 2) DTT, 3) DTT+ ionomycin (I)+6-DMAP. Materials and Meth...

Ionomycin is a calcium ionophore that induces release of calcium ions (Ca(2+)) from cellular storage to cytoplasm and Ca(2+) influx from the outside of the cell. We investigated the effect of ionomycin on endoplasmic reticulum (ER)-Golgi transport in the vesicular stomatitis virus glycoprotein (VSV-G) system. Ionomycin inhibited transport of VSV-G in a concentration-dependent manner in baby ham...

In fura-2-loaded ECV304 cells ionomycin elicited a saturable biphasic change in intracellular Ca2+ concentration ([Ca2+]i), where the initial phase represented mobilization of intracellular stores and the sustained component represented Ca2+ influx. To examine whether ionomycin could stimulate influx via a store-dependent mechanism. Mn2+ entry was monitored by the quenching of fura-2 fluorescen...

Elevating cytosolic Ca(2+) stimulates glucose uptake in skeletal muscle, but how Ca(2+) affects intracellular traffic of GLUT4 is unknown. In tissue, changes in Ca(2+) leading to contraction preclude analysis of the impact of individual, Ca(2+)-derived signals. In L6 muscle cells stably expressing GLUT4myc, the Ca(2+) ionophore ionomycin raised cytosolic Ca(2+) and caused a gain in cell surface...

Ionomycin is a Ca(2+)-selective ionophore that is widely used to increase intracellular Ca(2+) levels in cell biology laboratories. It is also occasionally used to activate eggs in the clinics practicing in vitro fertilization. However, neither the precise molecular action of ionomycin nor its secondary effects on the eggs' structure and function is well known. In this communication we have stu...

We hypothesized that calcium and 1,2-diacylglycerols stimulated human neutrophil (PMN) protein kinase C (EC 2.7.1.37) in a two-step mechanism. The proposed mechanism entails (1) increased insoluble protein kinase C activity and (2) endogenous protein phosphorylation, events which have not been biochemically dissociated. PMN which were treated with 100 nM ionomycin shifted protein kinase C activ...

This study determines the efficiency of sequential calcium treatments (electroporation or ionomycin) combined with protein synthesis (cycloheximide) or phosphorylation inhibitors (6-dimethylaminopurine) or the specific maturation promoting factor (MPF) inhibitor, roscovitine, in inducing artificial activation and development of rhesus macaque parthenotes or nuclear transfer embryos. Exposure of...

Exposure of erythrocytes to the Ca2+ ionophore ionomycin has recently been shown to induce cell shrinkage, cell membrane blebbing, and breakdown of phosphatidylserine asymmetry, all features typical of apoptosis of nucleated cells. Although breakdown of phosphatidylserine asymmetry is thought to result from activation of a Ca2+-sensitive scramblase, the mechanism and role of cell shrinkage have...

Abstract Study question Can we use a physiological compound to trigger oocyte activation in couples undergoing ICSI with history of fertilization failure due sperm activating factor deficiency? Summary answer In pilot sibling study, using recombinant human phospholipase C-zeta (rhPLCζ) yielded comparable compared conventional method ionomycin. What is known already overcomes most forms male gam...