The gut microbiota and microbially produced short chain fatty acids (SCFAs) are increasingly linked to type 2 diabetes (T2D), particularly in the context of dietary transitions from fiber-rich to more ultra-processed foods. Data in African origin populations are lacking. We examined the cross-sectional relationships between the gut microbiota, SCFAs, and T2D by performing amplicon sequencing and targeted metabolomics from fecal samples and measuring fasting glucose, insulin, and C-peptide in 1505 African origin middle-aged adults from Ghana, South Africa, Jamaica, Seychelles, and the US. Microbial diversity and SCFAs were highest among Ghanaian and lowest among US participants. T2D was associated with lower microbial diversity, but not when stratifying by site. Differential abundance analysis (adjusted for site, sex, BMI, and age) identified microbes associated with T2D: Romboutsia was negatively associated with T2D, while positively associated taxa included Escherichia−Shigella sp., Dielma fastidiosa, Klebsiella, and Bacteroides vulgatus. Several species that were differentially abundant by T2D showed strong correlations with SCFA concentrations, although the significance varied by site. Our results suggest that associations between the gut microbiota, SCFAs, and T2D may differ by environmental, dietary, and ecological contexts. Amid the shifting global dietary patterns, further research is needed to inform gut microbiota-targeted approaches to address the global T2D burden.
Plant domestication studies have traditionally focused on morphological factors that are under direct selection, e.g., fruit size, overlooking the consequences of domestication on ecosystem services. We addressed this knowledge gap by documenting for first time the soil carbon (C) sequestration potential in wild relatives and domesticated cultivars of breadfruit (Artocarpus), a long-lived tree crop. We evaluated aggregate-bound and bulk organic C pools in breadfruit wild relatives and domesticates in soils that varied in nitrogen (N) and phosphorus (P) fertility with management practices (fertilizer and mulch). We determined whether C levels were linked to plant domestication, abiotic factors (N, P, pH, and texture), or biotic factors with known links to C accrual (arbuscular mycorrhizal fungi (AMF), and microbial biomass). In low N or N: P soils, increasing breadfruit domestication was associated with reductions in macroaggregate C (by 50%) and bulk C (host determinism); these shifts were associated with AMF hyphal productivity (50% lower than in wild relatives), soil N and P, and microbial biomass. With a high soil N fertility, the levels of aggregate and bulk soil C were similar between wild relatives and domesticates (plasticity). Despite the limited number of cultivars sampled (n = 10) and the different management practices among sites, our findings suggest domestication effects on ecosystem services, especially those modulated by AMF and soil N fertility. The calculated soil C stocks averaged 99.5 Mg C/ha (range 70-122 Mg C/ha), supporting the possibility of C accrual in breadfruit agroforestry.
Roots are responsible for soil water uptake, yet little is known about how variation in fine-root traits relates to whole-tree water movement, particularly during periods of drought. By combining a 3-yr dataset monitoring sap flow rates with measures of fine-root biomass, length, and morphology across 10 tree species, we addressed hypotheses concerning the role of fine-root system size and morphology in determining tree responses to summer drought as well as potential changes in their relative importance under more severe droughts. Greater fine-root biomass and length did not enable trees to maintain high rates of sap flow during drought, whereas the morphological traits, specific root length and specific root area, were linked to sustained sap flow rates during drought. We found that all species, irrespective of root traits, progressively reduced their sap flow under more extreme drought conditions, although more acquisitive root morphology was still associated with smaller reductions. Our results run counter to long-standing assumptions that larger root systems are better able to access soil water and maintain photosynthetic activity during drought. Instead, we find evidence that root morphology at least partially determines the capacity for water uptake and movement as soil moisture declines.
In cold climatic zones, highway transportation routes are significant contributors to sediment-accumulated chloride ions (Cl-). Bioswale projects are designed to slow and treat roadway runoff and thereby meter the release of salts, but bioswale function is compromised over time as sediments become saturated with pollutants. This two-year project sought to test innovative practices to improve the function of Illinois Tollway (hereafter, Tollway) bioswales by investigating the effect of biochar addition (20 T/ha) and invasive plant harvesting on: (1) invasive cattail (Typha) dominance, (2) bioswale sediment chloride retention, and (3) harvestable chloride ions associated with living-green Typha tissues across a two-year field study in northeastern Illinois. We found that a single 20 T/ha biochar application resulted in significant increases in Typha [Dry Mass (g/m(2)) and Stem Count (count/m(2)), p <= 0.05] and sediment chloride concentration (ppm) [p <= 0.05]. Harvest did not significantly influence Typha standing stocks (p > 0.05) but did lead to a significant increase in harvestable chloride associated with living-green Typha tissues over the two-year study. This research demonstrates that a single 20 T/ha biochar application coupled with harvest of aboveground Typha biomass is a pathway for scalable management strategies to remove chloride and invasive standing stocks.
Despite the increasing occurrence of privacy breaches involving smart service systems, organizations lack evidence-based guidance on which trust repair strategies work, particularly beyond apologies or compensation. This study systematically evaluates the relative effectiveness of three verbal trust repair strategies (apology, denial, reticence) and three substantive strategies (compensation, regulation, third-party involvement), applied individually and in combination. We also examine the moderating role of violation type (competence-based vs. integrity-based) on repair strategy effectiveness. We conducted a scenario-based experiment using policy-capturing methodology that we assessed with a fixed-effects regression model for panel data. Seventy-seven long-term smart home users assessed post-repair trust following simulated privacy breaches and the subsequent application of diverse repair strategies. Our results identify apology as the most effective verbal strategy, while regulation is the most effective substantive strategy. Combinations of verbal and substantive strategies generally outperform isolated strategies, except when third-party involvement is included, which shows limited benefit. Unexpectedly, we found that the violation type did not significantly moderate the effectiveness of any of the examined trust repair strategies. This study contributes to research by (1) providing a comprehensive comparison of verbal and substantive trust repair strategies in a unified design, (2) demonstrating how trust repair strategy combinations perform synergistically or in tension, (3) challenging the prevailing assumption of the competence-integrity violation type distinction for trust repair strategy effectiveness, and (4) advancing understanding of trust repair for the high-vulnerability context of smart service systems, where the intersection of digital and physical risks amplifies the consequences of privacy breaches for customers.
