a pvc membrane fe(iii) ion selective electrode has been constructed using a new macrocyclic asmembrane carrier.the electrode exhibits a good potentiometric response for fe(iii) over a wideconcentration range 1.0×10-4 to 1.0×10-1m with a slope 19.4±0.5 mv/decade a and a working phrange of 6.5-9.0. it has a fast response time ≤30s.the best performance was observed with themembrance having the 30....

Incorporation of A23187 ionophore into the human-hamster fertilization system clearly improves the ability of human spermatozoa to penetrate zona-free hamster oocytes. Thus, an increasing number of laboratories working in human sperm cytogenetics have substituted classical incubation with Biggers-Whitten-Whittingham (BWW) medium plus human serum albumin (HSA) by pretreatment of spermatozoa with...

1. The effects of external Ca2+, EGTA, ionophore A23187, CN-, dinitrophenol and iodoacetamide on the rate of protein degradation in the rat diaphragm and epitrochlearis muscles in vitro were investigated. 2. External Ca2+ increased protein degradation when compared with external EGTA. Protein degradation was further increased by Ca2+ + ionophore A23187. 3. EGTA and ionophore A23187 decreased AT...

OBJECTIVE To determine if ionophore-resistant ruminal bacteria are cross-resistant to other classes of antibiotics. Clostridium aminophilum was used as a model organism because this Gram-positive ruminal bacterium can adapt to ionophores (monensin and lasalocid). Non-adapted cultures lagged for at least 12 h with 1 microM monensin or lasalocid, but initiated no growth if the concentration was 1...

PURPOSE To determine if the susceptibility of rat lenses to cataract formation in culture changes with increasing age and to investigate the regional differences in crystallin degradation and insolubilization during the formation of cataracts in cultured lenses. METHODS Lenses from 4-week-old (young group) and 12-week-old (adult group) rats were divided into four subgroups: noncultured contro...

The role of Ca2+ on insulin release has been studied by the use of ionophore A23187. The ionophore complexes divalent cations and permits Ca2+ entry into cells by acting as a carrier in the plasma membranes. Cultured cells obtained by enzymatic digestion of pancreases from newborn rats were studied on the 3rd day of culture. With Ca2+ in the incubation medium the ionophore induced sustained ins...

salinomycin is a monocarboxylic polyether ionophore with antimicrobial properties. it is a dietaryadditive used as a growth promoter for ruminants and as a coccidiostat in chickens. the mechanism of actionof ionophores at the cellular level is to selectively bind certain ions creating intra and extracellularbiochemical disturbances. clinical signs of ionophore intoxication are non specific and ...

oocyte activation (aoa), results in high fertilization rates. objective: this prospective, randomized, unblinded clinical study aimed to evaluate the efficiency of calcium ionophore on fertilization and pregnancy rate after intracytoplasmic sperm injection (icsi) in infertile men suffer from teratoospermia. materials and methods: thirty eight women with teratoospermic partner underwent icsi wit...

In vitro matured pig oocytes were activated using a combined treatment of calcium ionophore A 23187 with cycloheximide. The oocytes were exposed to ionophore (10, 25 or 50 microM) for 0.5, 1, 3, 5 or 7 min and then cultured with cycloheximide (0 or 10 microg/ml) for 6 h. Cycloheximide treatment significantly increased the activation rate of oocytes and the percentage of oocytes that were able t...

A23187 is a carboxylic acid antibiotic which simultaneously uncouples oxidative phosphorylation and inhibits ATPase of rat liver mitochondria incubated in a magnesium-free medium. The antibiotic acts as a freely mobile carrier to transport calcium and magnesium, but not potassium, from an aqueous medium buffered at pH 7.4 into a bulk organic phase. A23187 causes a progressive release of endogen...