Manganese Transport, Trafficking and Function in Invertebrates

Abstract

Manganese is an essential trace metal. Microorganisms including bacteria, yeasts, and small multicellular animals, such as nematodes, are constantly challenged with changing environmental conditions that may limit manganese availability or expose the organisms to excess or toxic concentrations of this metal. Transport systems for the uptake, efflux, and intracellular distribution of manganese have been identified in several invertebrate microorganisms and those from bacterial systems, the yeast Saccharomyces cerevisiae, and the nematode Caenorhabditis elegans are discussed herein. These transporters allow organisms to survive under a variety of environmental conditions by mediating stringent control of intracellular manganese content. Regulation of manganese transporters, both at transcriptional and post-translational levels, is a key to this tight control of manganese uptake. The mechanisms of manganese uptake, distribution, and elimination identified in bacteria, yeasts, and nematodes are likely to be conserved, at least in part, in more complicated invertebrate organisms.

Impact of Different Trace Elements on the Growth and Proteome of Two Strains of Granulicella, Class “Acidobacteriia”

“…The evaluation of the predicted genes in both did not reveal the presence of common genes involved in Mn regulation, such as the transcriptional regulator mntR (Jensen and Jensen, 2014). This result implies that the homeostasis of Mn in Granulicella strains is under control of another transcriptional regulator.…”

“…It is a co-factor of a wide range of enzymes, being vital in specific metabolic pathways, such as sugar, lipid, and protein catabolism (Jensen and Jensen, 2014), oxygenic photosynthesis in cyanobacteria (Kehres and Maguire, 2003;Cvetkovic et al, 2010), signal transduction, stringent response, sporulation, and pathogenesis (Kehres and Maguire, 2003;Jensen and Jensen, 2014). One of the most widely known and studied Mn functions is the detoxification of ROS, where it is a redox-active co-factor in free radical detoxifying enzymes, such as Mn-superoxide dismutase (MnSod) and mangani-catalase (Jakubovics and Jenkinson, 2001;Jensen and Jensen, 2014). Additionally, the detoxifying capaticities of Mn are not only enzyme-mediated, since non-protein complexes of Mn can also work as antioxidants when enzymes are not sufficient (Jensen and Jensen, 2014).…”

“…One of the most widely known and studied Mn functions is the detoxification of ROS, where it is a redox-active co-factor in free radical detoxifying enzymes, such as Mn-superoxide dismutase (MnSod) and mangani-catalase (Jakubovics and Jenkinson, 2001;Jensen and Jensen, 2014). Additionally, the detoxifying capaticities of Mn are not only enzyme-mediated, since non-protein complexes of Mn can also work as antioxidants when enzymes are not sufficient (Jensen and Jensen, 2014). Nonetheless, Mn homeostasis needs a refined balance, since Mn can bind to Mg-binding sites in enzymes and regulators, causing mismetallation, which can have deleterious effects in the cells (Hohle and O'Brian, 2014;Chandrangsu et al, 2017).…”

A fluorescent activatable probe for imaging intracellular Mg2+

“… 32 , 33 Mn 2+ is present in cells in a relatively broad range of concentrations ( i.e. between 0.04 and 2 mM) 34 whereas Zn 2+ is predominantly bound as a co-factor in protein complexes 35 and found as a free cation in cells at very low concentrations ( i.e. in the pM range).…”

Competitive Exclusion Is a Major Bioprotective Mechanism of Lactobacilli against Fungal Spoilage in Fermented Milk Products

“…Manganese (Mn) is an essential trace element that is a key cofactor in all kingdoms of life, making it important for the growth of bacteria, yeast, and mold (20). The two major manganese uptake systems in LAB are the NRAMP-type transporter MntH and the ABC transporter SitABC.…”