Whole body metabolism is improved by hemin added to high fat diet while counteracted by nitrite: a mouse model of processed meat consumption

Alleviation of arsenic toxicity in pepper plants by aminolevulinic acid and heme through modulating its sequestration and distribution within cell organelles

Aminolevulinic acid (ALA) is essential for chlorophyll and heme synthesis. However, whether heme interacts with ALA to elicit antioxidants in arsenic (As)-exposed plants is still unknown. ALA was applied daily to pepper plants for 3 days prior to beginning As stress (As-S). Then, As-S was initiated for 14 days by employing sodium hydrogen arsenate heptahydrate (0.1 mM AsV). Arsenic treatment decreased photosynthetic pigments (chl a by 38% and chl b by 28%), biomass by 24%, and heme by 47% content, but it elevated contents of malondialdehyde (MDA) by 3.3-fold, hydrogen peroxide (H₂O₂) by 2.3-fold, glutathione (GSH), methylglyoxal (MG), and phytochelatins (PCs) and electrolyte leakage (EL) by 2.3-fold along with enhanced subcellular As concentration in the pepper plant's roots and leaves. The supplementation of ALA to the As-S-pepper seedlings enhanced the amount of chlorophyll, heme content, and antioxidant enzyme activity as well as plant growth, while it reduced the levels of H₂O₂, MDA, and EL. ALA boosted GSH and phytochelates (PCs) in the As-S-seedlings by controlling As sequestration and rendering it harmless. The addition of ALA enhanced the amount of As that accumulated in the root vacuoles and reduced the poisonousness of the soluble As in the vacuoles. The ALA treatment facilitated the deposition and fixation of As in the vacuoles and cell walls, thereby reducing the transport of As to other cell organelles. This mechanism may have contributed to the observed decrease in As accumulation in the leaves. The administration of 0.5 mM hemin (H) (a source of heme) significantly enhanced ALA-induced arsenic stress tolerance. Hemopexin (Hx, 0.4 μg L^-1), a heme scavenger, was treated with the As-S plants along with ALA and ALA + H to observe if heme was a factor in ALA's increased As-S tolerance. Heme synthesis/accumulation in the pepper plants was reduced by Hx, which counteracted the positive effects of ALA. Supplementation of H along with ALA + Hx reversed the negative effects of Hx, demonstrating that heme is required for ALA-induced seedling As-S tolerance.

Bioengineered Lab-Grown Meat-like Constructs through 3D Bioprinting of Antioxidative Protein Hydrolysates

Lab-grown bovine meat analogues are emerging alternatives to animal sacrifices for cultured meat production. The most challenging aspect of the production process is the rapid proliferation of cells and establishment of the desired 3D structure for mass production. In this study, we developed a direct ink writing-based 3D-bioprinted meat culture platform composed of 6% (w/v) alginate and 4% (w/v) gelatin (Alg/Gel)-based hydrogel scaffolds supplemented with naturally derived protein hydrolysates (PHs; 10%) from highly nutritive plants (soybean, pigeon pea, and wheat), and some selected edible insects (beetles, crickets, and mealworms) on in vitro proliferation of bovine myosatellite cells (bMSCs) extracted from fresh meat samples. The developed bioink exhibited excellent shear-thinning behavior (n < 1) and mechanical stability during 3D bioprinting. Commercial proteases (Alcalase, Neutrase, and Flavourzyme) were used for protein hydrolysis. The resulting hydrolysates exhibited lower-molecular-weight bands (12-50 kDa) than those of crude isolates (55-160 kDa), as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The degree of hydrolysis was higher in the presence of Alcalase for both plant (34%) and insect (62%) PHs than other enzymes. The 3D-printed hydrogel scaffolds displayed excellent bioactivity and stability after 7 days of incubation. The developed prototype structure (pepperoni meat, 20 × 20 × 5 mm) provided a highly stable, nutritious, and mechanically strong structure that supported the rapid proliferation of myoblasts in a low-serum environment during the entire culture period. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay enhanced the free radical reduction of Alcalase- and Neutrase-treated PHs. Furthermore, the bioprinted bMSCs displayed early myogenesis (desmin and Pax7) in the presence of PHs, suggesting its role in bMSC differentiation. In conclusion, we developed a 3D bioprinted and bioactive meat culture platform using Alg/Gel/PHs as a printable and edible component for the mass production of cultured meat.