Direct interspecies electron transfer (DIET) has important implications for the design and operation of biological treatment processes.

Amending anaerobic digesters with pyrogenic carbonaceous materials (PCMs) has been suggested to improve methane (CH₄) production by enabling electron conduction between fermenters and methanogens. This enhancement has been attributed to the electrical conductivity of some PCMs. Properties other than conductivity have received little attention, leaving uncertain the primary drivers of the observed improvements. Accordingly, the objective of this study was to relate the electrical conductivity, adsorptive behavior, pH effects, and surface properties of PCMs to CH₄ production rates and CH₄ recoveries in swine wastewater-fed, short-term anaerobic batch reactors. Three types of PCM particles [graphite, biochar, and activated carbon (AC)] in two size ranges and three particle loadings were tested and compared to non-conductive glass particles and no-particle controls. Graphite amendments resulted in higher CH₄ production rates and CH₄ recoveries than the no-particle controls and showed improvements with increased particle loadings. The impact of biochar and AC amendments depended on particle sizes and loadings, with granule amendments generally exceeding or matching the controls. Powdered biochar and AC amendments substantially decreased the performance. Material conductivity was a poor predictor of CH₄ production rates, and bulk solution pH changes due to particle amendments could not explain reactor performance discrepancies. Adsorption was a critical material property controlling the fate of wastewater chemical oxygen demand (COD). Powdered biochar and AC, which adsorbed more COD than graphite and glass, resulted in lower COD to CH₄ conversion. These results indicate that PCM properties other than conductivity, such as adsorption, can strongly impact short-term bioreactor performance. These properties should be taken into consideration when selecting and optimizing PCMs for biological-based technologies.

INTRODUCTION: Alzheimer's disease (AD) has been regarded as a brain‐first disorder. Emerging evidence suggests that the gut may influence central nervous system pathology, but the mechanisms remain unclear. METHODS: We conducted a proteomic and microbial analysis of transverse colon samples from clinically and pathologically confirmed AD and control cases. RESULTS: In the AD gut samples, antimicrobial humoral response and oxidative stress response were downregulated, while catabolic processes and insulin signaling were upregulated. Several complement (e.g., C5) and synaptic (e.g., synaptophysin) proteins were downregulated. Amyloid beta 42 was detected at higher levels. Christensenellaceae , Desulfovibrio , and Candida tropicalis amplicon sequence variants were higher in abundance, while Streptococcus , Lachnospiraceae , Blautia , and Nakaseomyces were lower. In general, bacterial composition correlated with AD clinical variables such as plaque and tangle burden. DISCUSSION: These findings underscore the gut's possible involvement in AD pathogenesis and provide new insights into potential biomarkers and therapeutic targets. Highlights: This study provides the first in‐depth analysis of the proteome and microbiome in AD transverse colon tissues. Multiple immune and oxidative stress response pathways were downregulated in AD, while metabolic pathways were upregulated. Synaptic protein, complement protein, and Aβ42 levels were significantly different between AD and controls. Transverse colon microbial composition was associated with AD clinical variables.

An emerging area of research extends work on couple functioning and physical health to gut health, a critical marker of general health and known to diminish with age. As a foray into this area, we conducted a pilot study to (1) determine the feasibility of remote data collection, including a fecal sample, from older adult couples, (2) examine within-couple concordance in gut microbiota composition, and (3) examine associations between relationship functioning and gut microbiota composition. Couples (N = 30) were recruited from the community. The participants’ demographic characteristics were as follows: M (SD) age = 66.6 (4.8), 53% female, 92% White, and 2% Hispanic. Two of the couples were same-sex. All 60 participants completed self-report measures and supplied a fecal sample for microbiome analysis. Microbial DNA was extracted from the samples, and the 16S rRNA gene V4 region was amplified and sequenced. The results indicated that individuals shared more similar gut microbial composition with their partners than with others in the sample, p < 0.0001. In addition, individuals with better relationship quality (greater relationship satisfaction and intimacy and less avoidant communication) had greater microbial diversity, p < 0.05, a sign of healthier gut microbiota. Further research with a larger and more diverse sample is warranted to elucidate mechanisms.