Acrylamide (AA) and nanoplastics (NPs) are common food toxicants. However, their combined toxicity and health risks call for further studies. This study aimed to investigate the combined toxicity of AA and polystyrene NPs (PS-NPs) in mice through drinking water exposure. Co-exposure to AA and PS-NPs aggravated colon and liver damage, including more severe inflammatory infiltration, higher levels of colonic and hepatic pro-inflammatory cytokines, and elevated serum content of lipopolysaccharide and activities of diamine oxidase, alanine aminotransferase, and aspartate aminotransferase compared to single exposures. Co-exposure also significantly downregulated the expression of colonic tight-junction genes ZO-1 and Claudin-5. Metabolomics revealed that co-exposure induced more profound metabolic disorders in the liver, particularly affecting amino acid and carbohydrate metabolism. 16S amplicon sequencing showed that co-exposure caused more drastic gut microbiota dysbiosis, characterized by a decrease in beneficial bacteria (unclassified_f__Oscillospiraceae, Roseburia, UCG-005, Ruminiclostridium, unclassified_o__Clostridia_UCG-014, Fournierella, and Acetatifactor) and an increase in pathogenic bacteria (Eubacterium_xylanophilum_group and Eubacterium_nodatum_group). Correlation analysis indicated a negative correlation between beneficial bacteria and intestinal-liver toxicity indicators and a positive correlation between pathogenic bacteria and these indicators. Overall, our findings showed that AA and PS-NPs exerted synergistic toxicity to the gut–liver axis in mammals, highlighting the higher health risks of their combined ingestion.

Iron (Fe) is an important metal element for the growth of bacteria. Many bacteria respond to Fe limitation through a variety of strategies. We previously isolated an endophyte Bacillus sp. WR13 from wheat root. However, whether and how this strain can cope with Fe-deficient environments remains unclear. In this study, the growth of WR13 under Fe starvation was investigated, and the underlying mechanisms of WR13 in response to Fe starvation were elucidated via genomics and iTRAQ-based proteomics. Under Fe limitation, WR13 showed a growth pattern similar to that of Fe sufficiency. Genomics analysis demonstrated that WR13 had gene clusters related to siderophore synthesis (dhbACEBF), transportation (bcbE), uptake (feuABC-yusV) and hydrolysis (besA). These genes were significantly up-regulated in Fe-starved WR13, which resulted in more siderophore production. Proteomics data revealed that many Fe-containing proteins such as ACO, HemQ, ferredoxin, CNP, and SufD were significantly reduced under Fe limitation. Meanwhile, significant decreases in many proteins involved in glycolysis, TCA cycle, pentose phosphate pathway; asparagine, glutamine, methionine, and serine metabolism; and phospholipid hydrolysis were also observed. Overall, this study shows that Bacillus sp. WR13 was able to respond to Fe limitation via multiple strategies and provides a theoretical basis for the application of WR13 in Fe-deficient soil.

Photosynthetic induction is a critical physiological process through which plants rapidly adjust their photosynthetic machinery in response to a step increase in light intensity. While steady-state photosynthetic responses to elevated CO₂ (eCO₂) are well characterized, the characteristics of photosynthetic induction in honeysuckle under varying CO₂ concentrations remain underexplored, particularly for ecologically important species such as honeysuckle (Lonicera japonica). In this study, we investigated the photosynthetic induction responses of L. japonica leaves subjected to an abrupt light transition from 100 to 1200 µmol m⁻² s⁻¹ under three CO₂ concentrations: 420 μmol mol⁻¹ (ambient, aCO₂), 620 μmol mol⁻¹ (medium, mCO₂), and 820 μmol mol⁻¹ (elevated, eCO₂). Key photosynthetic parameters, including net photosynthetic rate (A), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), and apparent maximum Rubisco carboxylation rate (V′_cmax), were continuously estimated throughout the induction process. Results showed that eCO₂ significantly enhanced steady-state A while simultaneously reducing g_s and V′_cmax, indicating that higher CO₂ availability drives carbon gain primarily through increased substrate supply rather than enhanced enzymatic performance. Importantly, the time required to reach 90% induction state of steady-state A (t_A90) and V′_cmax (t_V′cmax90) decreased markedly with increasing CO₂. Time-integrated limitation analysis revealed that biochemical limitation consistently dominated the induction process regardless of CO₂ treatment, while stomatal limitation remained uniformly low. These findings demonstrate that eCO₂ substantially accelerated photosynthetic induction in L. japonica, as reflected by faster gas-exchange-derived induction parameters (e.g., t_A90 and t_V′cmax90), without altering the fundamental limitation hierarchy governing the induction process.