Soil Microbiome Dynamics During Pyritic Mine Tailing Phytostabilization: Understanding Microbial Bioindicators of Soil Acidification

Challenges to the reclamation of pyritic mine tailings arise from in situ acid generation that severely constrains the growth of natural revegetation. While acid mine drainage (AMD) microbial communities are well-studied under highly acidic conditions, fewer studies document the dynamics of microbial communities that generate acid from pyritic material under less acidic conditions that can allow establishment and support of plant growth. This research characterizes the taxonomic composition dynamics of microbial communities present during a 6-year compost-assisted phytostabilization field study in extremely acidic pyritic mine tailings. A complementary microcosm experiment was performed to identify successional community populations that enable the acidification process across a pH gradient. Taxonomic profiles of the microbial populations in both the field study and microcosms reveal shifts in microbial communities that play pivotal roles in facilitating acidification during the transition between moderately and highly acidic conditions. The potential co-occurrence of organoheterotrophic and lithoautotrophic energy metabolisms during acid generation suggests the importance of both groups in facilitating acidification. Taken together, this research suggests that key microbial populations associated with pH transitions could be used as bioindicators for either sustained future plant growth or for acid generation conditions that inhibit further plant growth.National Institute of Environmental and Health Sciences (NIEHS) Superfund Research Program (SRP) [P42 ES004940]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

One-Pot Green Synthesis and Bioapplication ofl-Arginine-Capped Superparamagnetic Fe3O4 Nanoparticles

Water-solublel-arginine-capped Fe3O4 nanoparticles were synthesized using a one-pot and green method. Nontoxic, renewable and inexpensive reagents including FeCl3,l-arginine, glycerol and water were chosen as raw materials. Fe3O4 nanoparticles show different dispersive states in acidic and alkaline solutions for the two distinct forms of surface bindingl-arginine. Powder X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the structure of Fe3O4 nanocrystals. The products behave like superparamagnetism at room temperature with saturation magnetization of 49.9 emu g−1 and negligible remanence or coercivity. In the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride, the anti-chloramphenicol monoclonal antibodies were connected to thel-arginine-capped magnetite nanoparticles. The as-prepared conjugates could be used in immunomagnetic assay

Biochemical identification of Aeromonas genospecies isolated from humans

One hundred phenotypic characteristics were determined for 138 clinical and environmental Aeromonas strains. Cluster analysis revealed three major phenons equivalent to the A. hydrophila, A. caviae, and A. sobria groups, each of which contained more than one genospecies and more than one named species. An excellent correlation was found between phenotypic identification and classification based on DNA relatedness. DNA hybridization groups within each of the phenotypic groups were also separable by using a few biochemical characteristics. Key tests were production of acid from or growth on D-sorbitol (which separated DNA hybridization group 3 from groups 1 and 2 within the A. hydrophila phenogroup), growth on citrate (which essentially separated DNA hybridization group 4 from groups 5A and 5B within the A. caviae phenogroup), and growth on DL-lactate (which separated DNA hybridization group 1 from groups 2 and 3 within the A. hydrophila phenogroup as well as group 5A from groups 4 and 5B within the A. caviae phenogroup). All except one strain in the A. sobria phenogroup belonged to DNA hybridization group 8. DNA hybridization groups were not equally distributed among clinical and environmental isolates, suggesting that strains of certain DNA hybridization groups might be less virulent than others.</jats:p