Mercury-Resistant Bacteria Associated With Macrophytes from A Polluted Lake

Abstract

Although Onondaga Lake in the Syracuse NY area is contaminated with high levels of mercury from past manufacturing operations, macrophytes in the lake have been able to survive, apparently withstanding mercury toxicity. Homogenates of three macrophyte species, Myriophyllum spicatum L., Potamogeton crispus L., and Stuckenia pectinata (L.) Borner, were phenotypically positive for the presence of mercury resistant bacteria. As determined by PCR analysis, the mercury resistant bacteria associated with M. spicatum and S. pectinata also possessed merA, one of the more widely studied essential genes in the mer operon. Analysis of 24 macrophyte taxa isolated from lakes across the United States, as well as biological supply houses, showed that mercury resistant bacteria were associated with all macrophytes. One possible explanation for the association of mercury resistant bacteria with macrophytes is described. This hypothesis suggests that Hg r bacteria may potentially ameliorate the negative effects that mercury elicits in macrophytes.

Diversity of Mercury Resistant Escherichia coli Strains Isolated from Aquatic Systems in Rio de Janeiro, Brazil

“…In our study, this methodology allowed the detection of variability in the 285 bp merA fragment among 14 E. coli strains (Figure 3). These results are in agreement with previous findings regarding the widespread occurrence and diversity of mercury resistance markers among distinct microbial populations from several environments, including soils and sediments, aquatic systems, animals, and clinical isolates [13,14,27,28,31,32]. The high plasticity found in the bacterial genome contributes to the diversity and dissemination of genetic markers favoring its circulation in geographically dispersed environments, even between distinct evolutionary lineages.…”

“…Considering the genetic of MerA expression, the Hg resistance (mer) operon presents a fundamental role in regulation, Hg binding, and organomercury degradation. It consists of essential genes as merR (responsible for the regulation of the operon), merT/merP (transport of mercury into the bacterial cell), merA (reduction of ionic mercury), and accessory genes such as merB, merC, merD, merE, merF, and merG, that encode proteins that add other skills to microorganisms [13,14]. MerR protein can act both as a repressor and activator of transcription.…”

Copper phytoremediation by a salt marsh plant (Phragmites australis) enhanced by autochthonous bioaugmentation

“…Moreover, these inoculations were carried out in soil plants rhizosphere to recover metal contaminated soils and studies with wetlands plants are to our knowledge almost inexistent. In fact, only two studies have shown rhizobacteria could be important in the accumulation and attenuation of toxicity of Hg to salt marsh plants ( de Souza et al, 1999;Caslake et al, 2006). But very recently a study by the authors showed autochthonous bioaugmentation with Cd resistant microorganisms could be useful for enhancement of P. australis phytoremediation potential for Cd contaminated estuarine sediments (Nunes da Silva et al, 2014).…”

Moving closer towards restoration of contaminated estuaries: Bioaugmentation with autochthonous rhizobacteria improves metal rhizoaccumulation in native Spartina maritima

“…Although the importance of the rhizosphere community for plant development in contaminated soils has been recognized, nothing is known about this aspect in S. maritima. Actually, the information is scarce in wetland plants in general [13][14][15][16][17].…”