The possibility of arsenic release and the potential role of Geobacter in arsenic biogeochemistry during in situ uranium bioremediation was investigated because increased availability of organic matter has been associated with substantial releases of arsenic in other subsurface environments. In a field experiment conducted at the Rifle, CO study site, groundwater arsenic concentrations increased when acetate was added. The number of transcripts from arrA, which codes for the a-subunit of dissimilatory As(V) reductase, and acr3, which codes for the arsenic pump protein Acr3, were determined with quantitative reverse transcription-PCR. Most of the arrA (460%) and acr3-1 (490%) sequences that were recovered were most similar to Geobacter species, while the majority of acr3-2 (450%) sequences were most closely related to Rhodoferax ferrireducens. Analysis of transcript abundance demonstrated that transcription of acr3-1 by the subsurface Geobacter community was correlated with arsenic concentrations in the groundwater. In contrast, Geobacter arrA transcript numbers lagged behind the major arsenic release and remained high even after arsenic concentrations declined. This suggested that factors other than As(V) availability regulated the transcription of arrA in situ, even though the presence of As(V) increased the transcription of arrA in cultures of Geobacter lovleyi, which was capable of As(V) reduction. These results demonstrate that subsurface Geobacter species can tightly regulate their physiological response to changes in groundwater arsenic concentrations. The transcriptomic approach developed here should be useful for the study of a diversity of other environments in which Geobacter species are considered to have an important influence on arsenic biogeochemistry.

Background: The term “food literacy” is increasingly used to describe the knowledge, skills and behaviours needed to meet food needs. The aim of this research was to determine content validity for an International Food Literacy Survey. Methods: The literature was searched for existing items to form an item pool to measure the eleven components of food literacy. Expert consensus was investigated through two related online surveys. Round 1 participants were researchers who had been involved in the development of a food literacy measure (n = 18). Round 2 participants were authors of papers who had used the term (n = 85). Level of agreement was determined quantitatively using the Content Validity Index and compared to open ended qualitative comments. Results: Consensus was achieved on 119 items. Components varied in the ease with which existing validated items could be found and the number of items achieving consensus. Items related to food prepared within the home were more likely to achieve consensus. Additional issues included limited shared understanding of the scope of the term, the validity of items varying according to context and a limited health focus. Conclusions: This study provides a valuable basis upon which to progress the development of a measure.

Geobacter species may be important agents in the bioremediation of organic and metal contaminants in the subsurface, but as yet unknown factors limit the in situ growth of subsurface Geobacter well below rates predicted by analysis of gene expression or in silico metabolic modeling. Analysis of the genomes of five different Geobacter species recovered from contaminated subsurface sites indicated that each of the isolates had been infected with phage. Geobacterassociated phage sequences were also detected by metagenomic and proteomic analysis of samples from a uranium-contaminated aquifer undergoing in situ bioremediation, and phage particles were detected by microscopic analysis in groundwater collected from sediment enrichment cultures. Transcript abundance for genes from the Geobacter-associated phage structural proteins, tail tube Gp19 and baseplate J, increased in the groundwater in response to the growth of Geobacter species when acetate was added, and then declined as the number of Geobacter decreased. Western blot analysis of a Geobacter-associated tail tube protein Gp19 in the groundwater demonstrated that its abundance tracked with the abundance of Geobacter species. These results suggest that the enhanced growth of Geobacter species in the subsurface associated with in situ uranium bioremediation increased the abundance and activity of Geobacter-associated phage and show that future studies should focus on how these phages might be influencing the ecology of this site.

(1) Background: The term ‘food literacy’ has gained momentum globally; however, a lack of clarity around its definition has resulted in inconsistencies in use of the term. Therefore, the objective was to conduct a systematic scoping review to describe the use, reach, application and definitions of the term ‘food literacy’ over time. (2) Methods: A search was conducted using the PRISMA-ScR guidelines in seven research databases without any date limitations up to 31 December 2019, searching simply for use of the term ‘food literacy’. (3) Results: Five hundred and forty-nine studies were included. The term ‘food literacy’ was used once in 243 articles (44%) and mentioned by researchers working in 41 countries. Original research was the most common article type (n = 429, 78%). Food literacy was published across 72 In Cites disciplines, with 456 (83%) articles from the last 5 years. In articles about food literacy (n = 82, 15%), review articles were twice as prevalent compared to the total number of articles (n = 10, 12% vs. n = 32, 6%). Fifty-one different definitions of food literacy were cited. (4) Conclusions: ‘Food literacy’ has been used frequently and broadly across differing article types and disciplines in academic literature internationally. However, agreement on a standardised definition of food literacy endorsed by a peak international agency is needed in order to progress the field.

The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uraniumcontaminated aquifer located in Rifle, CO, USA, acetate amendments initially promoted the growth of metal-reducing Geobacter species, followed by the growth of sulfate reducers, as observed previously. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater before the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the ameboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a preypredator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.