The ionosphere is where Earth’s atmosphere meets space The ionosphere stretches roughly 50 to 400 miles above Earth's surface, right at the edge of space. Along with the neutral upper atmosphere, the ionosphere forms the boundary between Earth's lower atmosphere — where we live and breathe — and the vacuum of space.
What is an ionophore?
Structurally, an ionophore contains a hydrophilic center and a hydrophobic portion that interacts with the membrane. Some ionophores are synthesized by microorganisms to import ions into their cells. Synthetic ion carriers have also been prepared. Ionophores selective for cations and anions have found many applications in analysis.
How do ionophores enter the cell membrane?
Ionophores. There are compounds that can bind to and become incorporated into biological membranes, forming a pathway which increases the membrane permeability to certain ions. They are relatively small molecules with a hydrophobic surface, which allows them to enter the lipid bilayer.
Are ionophores cytotoxic?
Ionophores are chemical compounds that reversibly bind and transport ions through biological membranes in the absence of a protein pore. This can disrupt the membrane potential, and thus these substances could exhibit cytotoxic properties.
What are lipophilic ionophores and why are they important?
Lipophilic ionophores are essential to achieving a high sensing selectivity with liquid membrane ISEs. As explained above, ion-exchanger-based membranes always show the same selectivity pattern that follows the solvation energies of the ions, but ionophore-based membranes may show very different selectivities.
Where are ionophores located?
Ionophores are low molecular weight natural products which dissolve in the plasma membrane or intracellular membranes of cells and make the membrane permeable to specific ions.
What are naturally occurring ionophores?
Polyether ionophores represent a large group of natural, biologically active substances produced by Streptomyces spp. They are lipid soluble and able to transport metal cations across cell membranes. Several of polyether ionophores are widely used as growth promoters in veterinary.
What are the 2 types of ionophores?
(a) Carrier ionophores reversibly bind ions and carry them through cell membranes. (b) Channel ionophores create channels within cell membranes to facilitate the transport of ions.
What are examples of ionophores?
Commercially available ionophores include monensin (Coban and Rumensin), lasalocid (Avatec and Bovatec), salinomycin (Bio-cox and Sacox), narasin (Monteban and Maxiban), maduramicin (Cygro), semduramicin (Aviax), and laidlomycin propionate (Cattlyst).
What is the purpose of ionophore?
Ionophores are a class of antibiotics that are used in cattle production to shift ruminal fermentation patterns. They are not bactericidal (they do not kill the bacteria); they simply inhibit their functionality and ability to reproduce.
Why are ionophores not used in humans?
While they are not used in humans due to toxicity, the use of ionophores may still carry risk, owing to the possibility of cross-resistance or coselection (Fig. 1). Resistance to any drug may be accompanied by cross-resistance to other antibiotics.
Do ionophores require energy?
By forming complexes with ions, ionophores rapidly shuttle ions across the membrane of the sporozoites at several thousand ions per second1. To attempt to counter the ion imbalance, the parasite uses energy to remove the excess ions.
What is the difference between ionophores and ion channels?
There are two types of ionophores; mobile ion carriers, which are small molecules that physically shield the ion from the surrounding environment and facilitate its movement across the plasma membrane, and channel-forming ionophores, which create a pore in the biological membrane to allow the ion to pass through.
How do you say ionophores?
Phonetic spelling of ionophoresiono-phores.ahy-on-uh-fawr. Pink Durgan.ionophores. Rogers Wolf.
Are ionophores toxic to humans?
Ionophores have been found to be toxic to animals and humans causing deaths at high levels and at present there exists no antidote or treatment for ionophore toxicity.
Why are ionophores toxic?
Ionophores have a pharmacologic effect by changing the flux of certain electrolytes across cell membranes. The doses of ionophores normally used in feed for other animals can be highly toxic to horses. Cardiac muscle, skeletal muscle, and the neurologic system are affected by ionophore toxicity.
Why are ionophores toxic to horses?
Ionophores have a pharmacologic effect by changing the flux of certain electrolytes across cell membranes. The doses of ionophores normally used in feed for other animals can be highly toxic to horses. Cardiac muscle, skeletal muscle, and the neurologic system are affected by ionophore toxicity.
Are ion channels ionophores?
There are two types of ionophores; mobile ion carriers, which are small molecules that physically shield the ion from the surrounding environment and facilitate its movement across the plasma membrane, and channel-forming ionophores, which create a pore in the biological membrane to allow the ion to pass through.
What is ionophores poultry?
Ionophores are mainly used to control coccidiosis, maintain intestinal integrity, avoid pain and suffering and help deliver good bird health and welfare.
What are ionophores in inorganic chemistry?
Ionophores are substances which facilitate the movement of ions into and/or through organic phases. The two major classes of compounds are the neutral ionophores, which form charged clathrate complexes with ions, and the carboxylic polyether ionophores which are neutral in the complexed state.
What is an ionophore?
Ionophores are a class of compounds that form complexes with specific ions and facilitate their transport across cell membranes. An ionophore typically has a hydrophilic pocket (or hole) that forms a binding site specific for a particular ion.
Why are ionophores used in electrochemistry?
Ionophores are widely used compounds in various areas of analytical chemistry for improvement of selectivity for determination of analytes , which are bound by them in heterogeneous systems. Their widest use in electrochemistry can be dated back to sixties, since then they are commonly applied as potential-forming compounds in ion-selective electrodes, mostly with liquid and plasticised membranes. Their lipophilicity, together with that of complexes formed with analytes, provides a possibility of incorporation them into BLMs. Numerous such systems have been reported in the literature for various BLM systems.
What is the name of the product that dissolves in the plasma membrane?
Ionophores . Ionophores are low molecular weight natural products which dissolve in the plasma membrane or intracellular membranes of cells and make the membrane permeable to specific ions. From: Methods in Cell Biology, 2004. Download as PDF.
Why are carboxylic ionophores important?
Ionophores play a significant role in improving the health and feed efficiency of livestock and poultry production. Of the two major subclasses, carboxylic ionophores form zwitterionic complexes with cations and promote electrically neutral cation exchange diffusion. These ionophores are used because they are better tolerated than the highly toxic neutral ionophores that form charged complexes capable of perturbing biologic membranes and action potentials. Presently, seven carboxylic ionophores are marketed in the United States and around the world for use as anticoccidials, growth promotion, improved production efficiency, and/or metabolic disease control in poultry and/or ruminants (Fig. 29.1 ).
Which ionophore has a high selectivity for K+?
Valinomycin carries K + across membranes with a high selectivity and has been used extensively to impose a high K + permeability on cell membranes. Monensin is a carrier with specificity for Na +. Hemisodium is a synthetic Na + ionophore with an even greater degree of selectivity for Na +.
How does ion flow occur?
Ion flow is driven by the electrochemical gradient resulting from the sum of the electric potential gradient and the ion concentration on either side of the membrane. In unstimulated cells, the electronegative interior favors the intake and hinders the escape of positive ions (the reverse is true for negative ions).
Why are there differences between concentrations of some solutes on either side of the plasma membrane?
There are notable differences between concentrations of some solutes on either side of the plasma membrane due to the activity of active transport systems that use the energy of ATP hydrolysis to promote the passage of substances against a gradient. For example, K + is the predominant cation in the intracellular space and Na + is the most abundant one in the extracellular space. Anion distribution also shows differences on either side of the membrane (p. 692).
What is an ionophore?
Ionophores are a class of compounds that form complexes with specific ions and facilitate their transport across cell membranes. An ionophore typically has a hydrophilic pocket (or hole) that forms a binding site specific for a particular ion.
What is the exterior surface of an ionophore?
The exterior surface of an ionophore is hydrophobic, allowing the complexed ion in its pocket to cross the hydrophobic membrane. A list of ionophores showing the ion specificity of each is given in Table 4.1. Ionophores are useful tools in cell physiology experiments.
What are the toxic effects of ionophores?
Ionophore toxic syndromes have resulted from overdosage, misuse, and drug interactions of feed additives, including formulations with monensin, lasalocid, salinomycin, narasin, maduramicin, laidlomycin, or semduramicin. Target organs damaged by toxic doses of ionophores were identified to include the heart and skeletal muscles in all species studied (reviewed by Novilla, 2012 ). The most important change is a toxic myopathy characterized by focal areas of degeneration, necrosis, and repair in cardiac and skeletal muscles with a variable inflammatory component ( Novilla and Folkerts, 1986; Van Vleet et al., 1991 ). The development of muscle lesions varies among domestic species. The heart is primarily affected in horses, skeletal muscle in pigs and dogs, and there is about equal tissue predilection in rats, chickens, and cattle. In addition, neurotoxic effects have been reported for lasalocid ( Shlosberg et al., 1985; Safran et al., 1993 ), narasin ( Novilla et al., 1994 ), and salinomycin ( Van der Linde-Sipman et al., 1999 ). Neuropathic changes occurred in peripheral nerves and the spinal cord. Focal swelling, fragmentation, loss of axons, and formation of digestion chambers filled with macrophages were observed in both sensory and motor nerves, and there was vacuolation with swelling, degeneration, and fragmentation of myelin sheaths and axons in the spinal cord.
What are the characteristics of ionophores?
Ionophores used successfully in ISEs normally share a number of important characteristics. They are highly lipophilic, that is, they are strongly retained in the hydrophobic membrane phase to ensure a long lifetime of the sensor. This is most often achieved by adding long alkyl chains, cyclohexyl, or adamantyl substituents to the structure. They possess a polar moiety or a set of polar functional groups responsible for ion recognition. The rest of the molecule contains hydrophobic regions that are compatible with the surrounding membrane solvent. The historical argument that ionophore molecules must also exhibit a high mobility has been largely disproved by the availability of a number of membrane materials where the ionophore is covalently anchored onto the polymeric backbone. The covalent anchoring still retains certain ion mobility in the membrane that appears to be sufficient for ISE applications.
Why does the ionophore clamp the mitochondrial close to zero?
However, at the same time the ionophore will clamp the mitochondrial Δψ close to zero because the K + concentrations in the cytoplasm and matrix are both approximately 100 mM. Nigericin can be added to cells at low concentrations with no deleterious effect except to slightly hyperpolarise the mitochondria.
Why are carboxylic ionophores important?
Ionophores play a significant role in improving the health and feed efficiency of livestock and poultry production. Of the two major subclasses, carboxylic ionophores form zwitterionic complexes with cations and promote electrically neutral cation exchange diffusion. These ionophores are used because they are better tolerated than the highly toxic neutral ionophores that form charged complexes capable of perturbing biologic membranes and action potentials. Presently, seven carboxylic ionophores are marketed in the United States and around the world for use as anticoccidials, growth promotion, improved production efficiency, and/or metabolic disease control in poultry and/or ruminants (Fig. 29.1 ).
What is the diagnosis of ionophore intoxication in horses?
Analysis of feed or stomach contents for ionophores is definitive. Treatment for ionophore-intoxicated horses is supportive because there is no specific therapy.
What are ionophores and polyphenols?
Ionophores & Polyphenols. An ionophore is a compound that can transport ions (like zinc) across biological cell membranes. Since zinc regulates adaptive immune cell function, these compounds can help maintain higher levels of intracellular zinc and decrease the replication of RNA viruses like influenza, SARS, and COVID-19.
What is the best ionophores for RNA?
Two ionophores that have been used to help increase cellular zinc levels in the treatment of some RNA viruses are chloroquine (a malarial drug discovered in 1934) and hydroxychloroquine. These compounds are related to quinine, which was originally derived from cinchona bark and first used to treat malaria. Popular in use with cocktails today, ...
Does quercetin have an ionophore?
In addition to all of these impressive supportive functions and applications, quercetin's most impressive quality may be its established zinc ionophore activity. As mentioned, an ionophore is a compound that can transport ions like zinc across cell membranes. As zinc regulates immune cell function, this may be able to decrease the replication of RNA viruses.
Are ionophores antibiotics?
In recent years, there have been calls from some scientists in Europe to consider scaling back the use of ionophores in poultry production due to concerns that they also show action against Gram-positive bacteria, in addition to having an effect on coccidia.
Mode of action mitigates risk
Ionophores’ biophysical mode of action explains the very low likelihood of resistance developing, they continued.
More resistance risk, plus environmental costs?
The veterinarians suggested that removal of ionophores may result in an increase in the use of therapeutic antibiotics and a greater risk of resistance developing, running against World Health Organization goals.
