Mars (United States)

Rare sugars are valuable for food and pharmaceutical applications. D-Mannose, a low-calorie sweetener, is traditionally produced via chemical extraction from plant biomass, which is unsustainable, while enzymatic methods suffer from low yields due to equilibrium limitations. Here, we demonstrate that Escherichia coli can naturally synthesize D-mannose from D-glucose through a phosphorylation-isomerization-dephosphorylation pathway. We enhanced D-mannose production by deleting competing pathways and overexpressing key biosynthetic genes. Unexpectedly, due to the promiscuous activity of the phosphatase HxpB, which dephosphorylates both D-mannose-6-phosphate (M6P) and D-sedoheptulose-7-phosphate (S7P), the engineered strain also produced D-sedoheptulose, a non-sweet rare sugar that inhibits C6 sugar consumption. Further metabolic engineering improved D-sedoheptulose production. These optimizations enabled the development of a co-production strain capable of producing both sugars with tunable ratios. By leveraging this unique sugar combination, our approach provides a sustainable route to rare sugar biosynthesis and opens new possibilities for functional food design and metabolic regulation.

Human noroviruses (HuNoVs), especially GII.4 strains, are the leading cause of acute viral gastroenteritis worldwide, yet no approved vaccines or antivirals exist. The pandemic GII.4 Sydney 2012 strain enters cells via membrane wounding and clathrin-independent carrier (CLIC)-mediated endocytosis, but it is unclear whether this entry mechanism is conserved across GII.4 variants. We compared early binding and entry of multiple GII.4 variants using wildtype and mutant GII.4 virus-like particles (VLPs) and modified human intestinal enteroid (HIE) cultures. Only a subset of GII.4 variants, including GII.4 Sydney, form distinct, HBGA-dependent capsid clusters on the cell surface. Clustering strains display significantly enhanced membrane wounding and endocytosis compared to non-clustering strains and outcompete non-clustering strains in replication assays as shown by complete inhibition of GII.4 Sydney replication. Using mutant VLPs and a HBGA non-binding mutant (R345A), we identified two residues, V333 and R339, in the VP1 protruding domain as critical mediators of clustering and entry. Mutations of these residues disrupt clustering and endocytosis without affecting HBGA binding, suggesting a role in post-attachment processes. While clustering and endocytosis are contingent upon VLP binding to HBGAs, inhibitor studies show they are independent of host protein glycosylation and are driven by lipid raft remodeling regulated by cholesterol and ceramides. Quantitative analyses across multiple GII.4 variants reveal an apparent dichotomy between clustering and non-clustering phenotypes, with clustering variants exhibiting higher entry competence. This distinction offers insight into strain-specific cell entry mechanisms and may aid in identifying the elusive proteinaceous HuNoV cellular receptor(s) supporting targeted therapeutic development.

d-Tagatose,a rare low-calorie sweetener, is ideal forbeverages due to its high solubility and low viscosity. Current enzymaticproduction methods from d-galactose or d-galactitolare limited by reaction reversibility, affecting the yield and purity.This study demonstrates that Escherichia coli harbors a thermodynamically favorable pathway for producing d-tagatose from d-glucose via phosphorylation–epimerization–dephosphorylationsteps. GatZ and KbaZ, annotated as aldolase chaperones, exhibit C4epimerization activity, converting d-fructose-6-phosphateto d-tagatose-6-phosphate. Structural analysis reveals activesite differences between these enzymes and class II aldolases, indicatingfunctional divergence. By exploiting the strains’ inabilityto metabolize d-tagatose, carbon starvation was applied toremove sugar byproducts. The engineered strains converted 45 g L–1d-glucose to d-tagatose, achievinga titer of 7.3 g L–1 and a productivity of 0.1 gL–1 h–1 under test tube conditions.This approach highlights E. coli asa promising host for efficient d-tagatose production.

Groundnuts are considered as one of the most important cultivated food crops globally. Groundnuts are used for vegetable oil production, which generate a variety of by-products, such as peanut press cake (PPC). Groundnuts are sensitive to infection by aflatoxigenic fungi. Aflatoxins are highly toxic to both humans and livestock, and contaminated crops containing high aflatoxin concentrations are deemed unsafe for consumption and trade. Innovative aflatoxin management strategies are needed and the insect production sector could be such a solution. Larvae of the black soldier fly (BSFL) were exposed to a PPC diet naturally contaminated with aflatoxins. After an exposure lasting eleven days, data on larval survival and biomass were collected. The PPC, BSFL and the residual material were analysed by LC-MS/MS to determine the concentration of eight different aflatoxins. A bio-accumulation factor and a molar mass balance were calculated. BSFL survival and biomass were not affected by exposure to the aflatoxin-contaminated PPC diet. The aflatoxins did not accumulate in the insect body, providing a promising outlook for the safety of rearing insects on aflatoxin contaminated PPC with the purpose of using them as food- and/or feed. Aflatoxin B1 (AFB1) was the dominant compound found in PPC. Formation of aflatoxicol, aflatoxin P1, and aflatoxin M1 occurred and taking these metabolites into account, a complete molar mass balance, thus full recovery, for AFB1 was obtained. This differs from previous studies using artificially spiked substrates in which 17–38% was recovered. This calls for additional studies comparing naturally contaminated with artificially spiked feedstuff.

Dietary flavanols are food constituents found in certain fruits and vegetables that have been linked to cognitive aging. Previous studies suggested that consumption of dietary flavanols might specifically be associated with the hippocampal-dependent memory component of cognitive aging and that memory benefits of a flavanol intervention might depend on habitual diet quality. Here, we tested these hypotheses in the context of a large-scale study of 3,562 older adults, who were randomly assigned to a 3-y intervention of cocoa extract (500 mg of cocoa flavanols per day) or a placebo [(COcoa Supplement and Multivitamin Outcomes Study) COSMOS-Web, NCT04582617]. Using the alternative Healthy Eating Index in all participants and a urine-based biomarker of flavanol intake in a subset of participants [n = 1,361], we show that habitual flavanol consumption and diet quality at baseline are positively and selectively correlated with hippocampal-dependent memory. While the prespecified primary end point testing for an intervention-related improvement in memory in all participants after 1 y was not statistically significant, the flavanol intervention restored memory among participants in lower tertiles of habitual diet quality or habitual flavanol consumption. Increases in the flavanol biomarker over the course of the trial were associated with improving memory. Collectively, our results allow dietary flavanols to be considered in the context of a depletion-repletion paradigm and suggest that low flavanol consumption can act as a driver of the hippocampal-dependent component of cognitive aging.

Cocoa flavanols and procyanidins (CFs), natural dietary bioactives, have been studied extensively over the past two decades for their potential health benefits. Research on their safety and efficacy is critically dependent upon on the ability to reliably characeterize the research materials that are utilized, and with growing consumer availability of CF-based products, reliable methods for the detection of potential adulteration are of increasing importance. This research focused on the development of a high performance liquid chromatography-tandem mass spectrometry method (HPLC-MS2) using primary standards and 13C-labelled procyanidins as internal standards. The ability of MS2 detection to discriminate A- and B-type procyanidins was demonstrated. Method performances were validated for degrees of polymerization up to four in seven model food matrices. Accuracy ranged from 90.9 to 125.4% and precision was < 10% at lower concentrations. Finally, the method was applied to cocoa-based samples and compared to the AOAC 2020.05 analytical protocol, supporting the use of NIST 8403 as reference material for HPLC-MS2 analysis.

The paper provides an overview of the current and potential social practices in the realm of space politics from the perspectives of critical theory of international relations and critical geopolitics, with the aim to find an answer to the question of what the purpose of collective human action in space ought to be to secure the cosmic flourishing of civilisation instead of opening new areas for imperial politics. The author employs a broader definition of space politics, understood as a complex of social and institutional practices related to decision-making on public issues concerning the design and implementation of national, transnational, and international programmes for the exploration and governing of outer space. The departing hypothesis is that there are a series of ethically challenging spots in space politics, which may be sparked by a utilitarian calculus, instrumentalised to preserve the neoliberal continuum of exploitation of natural resources, production and world trade in the age of late capitalism. The analysis focuses on the points of collision between the utilitarian calculus - embodied in the corporate innovative endeavours and technological achievements - and the principles embedded in the imperative of responsibility, as well as the concepts of the global commons, space sustainability, and interstellar flourishing. The author concludes that the harmful long-term or even permanent effects of the plausible development of space imperialism, grounded on the misuse of scientific and technological knowledge to pursue national or corporate interests to the detriment of marginalised groups of the world population, could be prevented only by the intellectual and political rejection of anthropocentrism in favour of the idea of interstellar flourishing.