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At least 91 records · Page 5

Bioremediation of a Common Product of Food Processing by a Human Gut Bacterium

Dramatic increases in processed food consumption represent a global health threat. Maillard reaction products (MRPs), which are common in processed foods, form upon heat-induced reaction of amino acids with reducing sugars and include advanced glycation end products with deleterious health effects. To examine how processed foods affect the microbiota, we fed gnotobiotic mice, colonized with 54 phylogenetically diverse human gut bacterial strains, defined sugar-rich diets containing whey as the protein source or a matched amino acid mixture. Whey or ϵ-fructoselysine, an MRP in whey and many processed foods, selectively increases Collinsella intestinalis absolute abundance and induces Collinsella expression of genomic loci directing import and metabolism of ϵ-fructoselysine to innocuous products. This locus is repressed by glucose in C. aerofaciens, whose abundance decreases with whey, but is not repressed in C. intestinalis. Finally, identifying gut organisms responding to and degrading potentially harmful processed food components has implications for food science, microbiome science, and public health.

59 BASIC BIOLOGICAL SCIENCES↗

Metallomics of two microorganisms relevant to heavy metal bioremediation reveal fundamental differences in metal assimilation and utilization

Although as many as half of all proteins are thought to require a metal cofactor, the metalloproteomes of microorganisms remain relatively unexplored. Microorganisms from different environments are likely to vary greatly in the metals that they assimilate, not just among the metals with well-characterized roles but also those lacking any known function. Herein we investigated the metal utilization of two microorganisms that were isolated from very similar environments and are of interest because of potential roles in the immobilization of heavy metals, such as uranium and chromium. The metals assimilated and their concentrations in the cytoplasm of Desulfovibrio vulgaris strain Hildenborough (DvH) and Enterobacter cloacae strain Hanford (EcH) varied dramatically, with a larger number of metals present in Enterobacter. For example, a total of 9 and 19 metals were assimilated into their cytoplasmic fractions, respectively, and DvH did not assimilate significant amounts of zinc or copper whereas EcH assimilated both. However, bioinformatic analysis of their genome sequences revealed a comparable number of predicted metalloproteins, 813 in DvH and 953 in EcH. These allowed some rationalization of the types of metal assimilated in some cases (Fe, Cu, Mo, W, V) but not in others (Zn, Nd, Ce, Pr, Dy, Hf and Th). It was also shown that U binds an unknown soluble protein in EcH but this incorporation was the result of extracellular U binding to cytoplasmic components after cell lysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Viral and bacterial community responses to stimulated Fe(III)–bioreduction during simulated subsurface bioremediation

The delivery of fermentable substrate(s) to subsurface environments stimulates Fe(III)–bioreduction and achieves detoxification of organic/inorganic contaminants. Although, much research has been conducted on the microbiology of such engineered systems at lab and field scales, little attention has been given to the phage–host interactions and virus community dynamics in these environments. The objective was to determine the responses of soil bacterial communities and viral assemblages to stimulated anaerobic Fe(III)–bioreduction following electron donor (e.g. acetate) addition. Microbial communities, including viral assemblages, were investigated after 60 days of Fe(III)–bioreduction in laboratory–scale columns continuously fed with acetate–amended artificial groundwater. Viral abundances were greatest in the influent section and decreased along the flow path. Acetate availability was important in influencing bacterial diversity, microbial interactions and viral abundance and community composition. The impact of acetate addition was most evident in the influent section of the columns. The increased relative abundance of Fe(III)–reducing bacteria coincided with an increase in viral abundance in areas of the columns exhibiting the most Fe(III) reduction. In conclusion, the genetic composition of viruses in these column sections also differed from the control column and distal sections of acetate–treated columns suggesting viral communities responded to biostimulated Fe(III)–bioreduction.

59 BASIC BIOLOGICAL SCIENCES↗

Gene Determinants for Mercury Bioremediation as Revealed by Draft Genome Sequence Analysis of Stenotrophomonas sp. Strain MA5

A soilborne Stenotrophomonas sp. strain (MA5) that is resistant to mercury was isolated. A draft genome sequence-based analysis revealed a suite of gene determinants to resist mercury and other heavy metals, multidrug efflux, stress response, and membrane transport, and these provide cues to a suite of mechanisms that underpin cellular survival in contaminated soil.

Pathak, Ashish↗

In Situ Bioremediation System Pantex Plant, Amarillo, Texas

Seepage velocity was low/measurable in wells with low saturated thickness, RDX/chrome not detected by PFM in injection wells but was detected in some nearby MWs - consistent with GW concentration data

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗