A feedlot growth-performance trial and a metabolism trial were conducted to evaluate the interaction of forage level (10 vs 20%) and monensin (0 vs 28 mg/kg, air-dry basis) on utilization of a steam-flaked corn-based finishing diet. There were no treatment interactions (P > .10) on feedlot cattle growth performance or site and extent of digestion of OM, ADF, N, and starch. Monensin supplementat...

Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation...

A ruminal fermentation study was used to investigate the relationship between forage quality and monensin-dependent amino acid-sparing. Two fistulated cows were fed three concentrations of chopped (2.5 to 5.0 cm in length) timothy and alfalfa hays (100:0, 50:50 and 0:100) and two levels of monensin (0 and 350 mg.cow-1.d-1). The diets were offered 12 times per day (9 kg of DM/d), and the rumen r...

We have observed a striking differential effect of the ionophore, monensin, on replication of influenza virus and vesicular stomatitis virus (VSV) in Madin-Darby canine kidney (MDCK) and baby hamster kidney (BHK21) cells. In MDCK cells, influenza virus is assembled at the apical surfaces, whereas VSV particles bud from the basolateral membranes; no such polarity of maturation is exhibited in BH...

Monensin is a carrier of cations through lipid membranes capable of exchanging sodium (potassium) cations for protons by an electroneutral mechanism, whereas its ethyl ester derivative ethyl-monensin is supposed to transport sodium (potassium) cations in an electrogenic manner. To elucidate mechanistic details of the ionophoric activity, ion fluxes mediated by monensin and ethyl-monensin were m...

The ionophore monensin displays potent activities against several coccidian parasites of veterinary and medical importance including the opportunistic pathogen of humans, Toxoplasma gondii. While monensin is used widely in animals, toxicity impedes its use in humans. Nonetheless, given its potency, understanding its mode of action would reveal vulnerable aspects of the parasite that can be expl...

Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage h...

Ruminal amino acid degradation is a nutritionally wasteful process that produces excess ruminal ammonia. Monensin inhibited the growth of monensin-sensitive, obligate amino acid-fermenting bacteria and decreased the ruminal ammonia concentrations of cattle. 16S rRNA probes indicated that monensin inhibited the growth of Peptostreptococcus anaerobius and Clostridium sticklandii in the rumen. Clo...

The spreading on glass of monensin-treated normal and Duchenne fibroblasts has been investigated with the intention of extending this approach to a study of the comparative spreading of these cells on differing substrata. Untreated normal and Duchenne fibroblasts varied considerably in their ability to spread on glass. The spreading properties of normal and DMD fibroblasts treated in four diffe...

Effectiveness of low level monensin supplementation on N utilization in lactating dairy cows fed alfalfa silage was assessed using 48 multiparous Holsteins. Cows were fed a covariate diet [% of dry matter (DM): 56% alfalfa silage, 39% ground high moisture corn, 3% soybean meal, 1% ground corn, 1% vitamin-mineral supplements] for 2 wk, then grouped by days in milk into blocks of 4. Cows were ran...