Manganese homeostasis

Que, Q. and Helmann, J. D. (2000). Manganese homeostasis in Bacillus subtilis is regulated by MntR, a bifunctional regulator related to the diphtheria toxin repressor family of proteins, Mol. Microbiol., 35, 1454-1468. 

Manganese nutriture of the chick has been a fertile area of investigation for over 50 years. Wilgus and associates (1) in 1936 reported that Mn would prevent perosis in chicks. Numerous research publications have since expanded the knowledge of Mn homeostasis in the chick. The chick is unique with regard to Mn. It has a higher Mn requirement than it s mammalian counterpart, and the Mn absorption efficiency in chicks is thought to be less than in mammals (2). 

Under identical experimental conditions iron deficiency defi-nately stimulates much more the transduodenal transport and intestinal uptake of radiomanganese than of radioiron (47,93). This could be explained by the much more stable absorption and other mechanisms in the intestine for iron than for manganese. Whereas the homeostasis of iron is maintained at the level of the intestinal... 

Biliary excretion provides the major route for manganese homeostatic control (7-9) this mechanism is apparently essential when intakes are high (10). However, there is evidence that absorption can also play a role in the manganese homeostasis in cattle (11, 12) and rats (10,13). 

Less is known about regulation of manganese homeostasis than other metals. However, several recent reviews of regulation of manganese in bacteria are available. ... 

A number of bacterial metal transporters belong to the family of ATP-binding cassette (ABC) transporter system (see Metallochaperones Metal Ion Homeostasis) These systems constitute one of the most abundant superfamilies of proteins. They are involved in the transport of a wide variety of substances and in many cellular processes. The zinc transporter ZnuA from E. Coli and Synechocystis sp. 6803, the proposed zinc transporter TroA from Treponema pallidum, and the proposed manganese transporter Streptococcus pneumoniae surface antigen, PsaA, are placed in cluster 9 of the ABC transporters. ... 

Brain extracellular concentrations of amino acids and divalent metals (e.g., manganese) are primarily regulated by astrocytes. Adequate glutamate homeostasis is essential for the normal functioning of the central nervous system (CNS), for example, glutamate is important for nitrogen metabolism and, along with aspartate, is the primary mediator of the excitatory... 

Abrams E, Lassiter JW, Miller WJ, et al. 1976b. Absorption as a factor in manganese homeostasis. J Anim Sci 42 630-636. 

SchroederHA,BalassaJJ, Tipton IH. 1966. Essential trace metals in man Manganese. A study in homeostasis. J ChronDis 19 545-571. 

Aschner M., 1999. Manganese Homeostasis in the CNS. Environmental Research Section A, 80 105-109. 

Aschner, J. L. and Aschner, M. (2005). Nutritional aspects of manganese homeostasis. Mol. 

The effect of manganese deficiency or excess on carbohydrate homeostasis have been studied by Keen, Hmley and coworkers, with some focus on pyruvate carboxylase and PEP carboxykinase [302-304]. Other evidence indicates that Mn(II) has an insulin-mimetic effect, acting to stimulate protein kinases or phosphatases that control enzymes involved in glycolysis, gluconeogenesis, or the hexose mono-P pathway [305-307]. A key role of Mn(II) in mucopolysaccharide metabolism has long been recognized [6]. 

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