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This study aimed to apply protein-rich red algal ( Pyropia yezoensis ) hydrolysates to formulate functional food using spray drying techniques. Four wall materials (WMs), namely gelatin, whey protein, starch, and dextrin, were used to observe the physicochemical properties and comparative efficiency in spray drying powders (SDP) formation. The efficiency varied from 25.85 ± 2.34% to 84.60 ± 4.87% in different WMs where the average particle size of the SDPs ranged between 23.49 ± 0.32 μm to 236.03 ± 0.72 μm. The morphological analysis of the SDPs was also conducted using SEM. FT-IR analysis of the WMs was different with SDPs and showed characteristic bands at some particular wavelengths, especially 3000–3300 cm −1 and 1000–1700 cm −1 , indicating the successful formation of SDPs. Additionally, analyses of thermal gravimetric and amino acid content were performed. The taurine and GABA content were at their highest levels in SDPs with dextrin as a WM (323.18 ± 0.38 mg (100 g) −1 and 21.70 ± 0.14 mg (100 g) −1 , respectively). The results of this study suggest that the SDP of P. yezoensis hydrolysates has commercial importance and can be used as a rich amino acid functional food material for humans.

The protein extracted from red algae Pyropia yezoensis has various biological activities, including anti-inflammatory, anticancer, antioxidant, and antiobesity properties. However, the effects of P. yezoensis protein (PYCP) on tumor necrosis factor-α (TNF-α)-induced muscle atrophy are unknown. Therefore, the present study investigated the protective effects and related mechanisms of PYCP against TNF-α-induced myotube atrophy in C2C12 myotubes. Treatment with TNF-α (20 ng/ml) for 48 h significantly reduced myotube viability and diameter and increased intracellular reactive oxygen species levels; these effects were significantly reversed in a dose-dependent manner following treatment with 25-100 µg/ml PYCP. PYCP inhibited the expression of TNF receptor-1 in TNF-α-induced myotubes. In addition, PYCP markedly downregulated the nuclear translocation of nuclear factor-κB (NF-κB) by inhibiting the phosphorylation of inhibitor of κB. Furthermore, PYCP treatment suppressed 20S proteasome activity, IL-6 production, and the expression of the E3 ubiquitin ligases, atrogin-1/muscle atrophy F-box and muscle RING-finger protein-1. Finally, PYCP treatment increased the protein expression levels of myoblast determination protein 1 and myogenin in TNF-α-induced myotubes. The present findings indicate that PYCP may protect against TNF-α-induced myotube atrophy by inhibiting the proinflammatory NF-κB pathway.

Dexamethasone (DEX), a synthetic glucocorticoid, causes skeletal muscle atrophy. This study examined the protective effects of Pyropia yezoensis peptide (PYP15) against DEX-induced myotube atrophy and its association with insulin-like growth factor-I (IGF-I) and the Akt/mammalian target of rapamycin (mTOR)-forkhead box O (FoxO) signaling pathway. To elucidate the molecular mechanisms underlying the effects of PYP15 on DEX-induced myotube atrophy, C2C12 myotubes were treated for 24 h with 100 μM DEX in the presence or absence of 500 ng/mL PYP15. Cell viability assays revealed no PYP15 toxicity in C2C12 myotubes. PYP15 activated the insulin-like growth factor-I receptor (IGF-IR) and Akt-mTORC1 signaling pathway in DEX-induced myotube atrophy. In addition, PYP15 markedly downregulated the nuclear translocation of transcription factors FoxO1 and FoxO3a, and inhibited 20S proteasome activity. Furthermore, PYP15 inhibited the autophagy-lysosomal pathway in DEX-stimulated myotube atrophy. Our findings suggest that PYP15 treatment protected against myotube atrophy by regulating IGF-I and the Akt-mTORC1-FoxO signaling pathway in skeletal muscle. Therefore, PYP15 treatment appears to exert protective effects against skeletal muscle atrophy.

Changes in atmospheric CO 2 concentration have played a central role in algal and plant adaptation and evolution. The commercially important red algal genus, Pyropia (Bangiales) appears to have responded to inorganic carbon (C i ) availability by evolving alternating heteromorphic generations that occupy distinct habitats. The leafy gametophyte inhabits the intertidal zone that undergoes frequent emersion, whereas the sporophyte conchocelis bores into mollusk shells. Here, we analyze a high-quality genome assembly of Pyropia yezoensis to elucidate the interplay between C i availability and life cycle evolution. We find horizontal gene transfers from bacteria and expansion of gene families (e.g. carbonic anhydrase, anti-oxidative related genes), many of which show gametophyte-specific expression or significant up-regulation in gametophyte in response to dehydration. In conchocelis, the release of HCO 3 - from shell promoted by carbonic anhydrase provides a source of C i . This hypothesis is supported by the incorporation of 13 C isotope by conchocelis when co-cultured with 13 C-labeled CaCO 3 . The nori producing seaweed Pyropia yezoensis has heteromorphic generations that occupy distinct habitats. Here, via genome assembly, transcriptome analysis, and 13 C isotope labeling, the authors show the interplay between inorganic carbon availability and life cycle evolution in the intertidal environment.

R-phycoerythrin (R-PE), a marine bioactive protein, is abundant in Porphyra yezoensis with high protein content. In this study, R-PE was purified using a deep eutectic solvents aqueous two-phase system (DES-ATPS), combined with ammonium sulphate precipitation, and characterized by certain techniques. Firstly, choline chloride-urea (ChCl-U) was selected as the suitable DES to form ATPS for R-PE extraction. Then, single-factor experiments were conducted: the purity (A565/A280) of R-PE was 3.825, and the yield was 69.99% (w/w) under optimal conditions (adding 0.040 mg R-PE to ChCl-U (0.35 g)/K2HPO4 (0.8 g/mL, 0.5 mL) and extracting for 20 min). The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results revealed that the purified R-PE contained three main bands. One band was presented after purification in native-PAGE. The UV-vis spectra showed characteristic absorption peaks at 495, 540, and 565 nm. R-PE displayed an emission wavelength at 570 nm when excited at 495 nm. All spectra results illustrated that the structure of R-PE remained unchanged throughout the process, proving the effectiveness of this method. Transmission electron microscope (TEM) showed that aggregation and surrounding phenomena were the driving forces for R-PE extraction. This study could provide a green and simple purification method of R-PE in drug development.

Bacteria and marine macroalgae form close associations, while various bacteria affect the morphogenesis and growth of macroalgae. Hyphomonas strains exhibit normal morphogenetic activity in protoplasts of the red alga Pyropia yezoensis (nori). However, the effects of the bacteria on the growth of Pyropia from protoplast cells to regenerated thalli remain unknown. Here, we assessed the growth of P. yezoensis and Pyropia tenera using combined cultures of three Hyphomonas strains (LNM10-16, SCM-2, and LNM-9) and three algal media (artificial seawater with vitamins, artificial seawater, and natural seawater) over 7 weeks. Third week after culture, the three Hyphomonas strains showed almost similar levels of normal growth activity for both Pyropia species. However, at 7 weeks, significant differences were observed among the three Hyphomonas strains in terms of length, length-to-width ratio, and normal morphology of Pyropia thalli. LNM10-16 significantly promoted the thalli length and length-to-width ratios of both Pyropia species in artificial seawater without vitamins and natural seawater, compared with the other two Hyphomonas strains. P. yezoensis cultured in artificial seawater with vitamins showed a much higher demand for LNM10-16 in development of the thalli length than P. tenera . These results may be explained by differences in the growth activities of Hyphomonas strains and the nutrient requirements of Pyropia species. Furthermore, the bacteria were more specifically attached to the rhizoid surfaces of both species. This study is the first to reveal that Hyphomonas strains affect the growth of Pyropia species by attaching to their rhizoids.

Phycoerythrin is a major light-harvesting pigment of red algae and cyanobacteria that is widely used as a fluorescent probe or as a colorant in the food and cosmetic industries. In this study, phycoerythrin was extracted from the red algae Pyropia yezoensis and purified by ammonium sulfate precipitation and various chromatography methods. The purified phycoerythrin was analyzed by UV-visible and fluorescence spectroscopy. The isolated pigment had the typical spectrum of R-phycoerythrin, with a trimmer state with absorbance maxima at 497, 536, and 565 nm. It was further purified and identified by LC-MS/MS and Mascot search. It showed a 100% sequence similarity with the R-phycoerythrin alpha subunit of Pyropia yezoensis. The molecular mass was 17.97 kDa. The antioxidant activity of the purified R-phycoerythrin alpha subunit was analyzed. It showed significant antioxidant activity in ABTS and FRAP assays and had significant cytotoxicity against HepG2 cells.

Although the role of phytohormones in higher plants is well established, their role in macroalgae remains poorly understood. 1-Aminocyclopropane-1-carboxylic acid (ACC) is the immediate precursor of the plant hormone ethylene. However, recent studies suggested that ACC also acts as a signaling molecule to regulate growth and development independently of ethylene biosynthesis in land plants and red algae. This study investigated the role of ACC in the sporophytes of the red alga Pyropia yezoensis . ACC treatment significantly inhibited the growth of P. yezoensis sporophytes, whereas ethephon, an ethylene-releasing compound, had no such effect. In addition, ACC treatment promoted the degradation of photosynthetic pigments, including chlorophyll, phycobiliprotein, and carotenoids. The investigation employed RNA sequencing to identify differentially expressed genes in response to ACC treatment in sporophytes. Notably, upregulated genes such as proteases were associated with catabolic processes. By contrast, genes related to anabolic processes such as photosynthesis, including light-harvesting complex protein and Calvin–Benson cycle enzymes, were downregulated in response to ACC treatment. ACC induced catabolic processes and repressed anabolic processes, indicating the promotion of resource reallocation in microscopic sporophytes.

Soil salinity is one of the major issues worldwide that affects plant growth and reduces agricultural productivity. Seaweed polysaccharides have been shown to promote crop growth and improve the resistance of plant to abiotic stresses. is a commercially important edible red alga in Southeast Asia. However, there is little research on the application of polysaccharides from in agriculture. The molecular weight (MW) of polysaccharides influences their properties. Therefore, in this study, four representative polysaccharides from (PP) with different MWs (MW: 3.2, 10.5, 29.0, and 48.8 kDa) were prepared by microwave-assisted acid hydrolysis. The relationship between the degradation of polysaccharides from (DPP) and their effects on plant salt tolerance was investigated. The results showed that exogenous PP and DPPs increased wheat seedling shoot and root lengths, and fresh and dry weights, alleviated membrane lipid peroxidation, increased the chlorophyll content and enhanced antioxidant activities. The expression level examination analysis of several Na /K transporter genes suggested that DPPs could protect plants from the damage of salt stress by coordinating the efflux and compartmentation of Na . The results demonstrated that polysaccharides could regulate antioxidant enzyme activities and modulate intracellular ion concentration, thereby to protect plants from salt stress damage. Furthermore, there was a significant correlation between the tolerance of wheat seedlings to salt stress and MW of polysaccharides. The results suggested that the lower-MW samples (DPP1, 3.2 kDa) most effectively protect wheat seedlings against salt stress.

Histone acetylation is one of the most pivotal epigenetic mechanisms in eukaryotes and has been tightly linked to the regulation of various genes controlling growth, development and response to environmental stresses in both animals and plants. Till date, the association of histone acetylation to dehydration stress in red algae and genes encoding the enzymes responsible for histone acetylation: histone acetyltransferases (HATs) or histone deacetylases (HDACs), remains largely unknown. In this study, in silico analysis of the red seaweed Pyropia yezoensis identified 6 HAT genes and 10 HDAC genes. These genes displayed good synteny in genome loci with their Pyropia haitanensis orthologs except for a putative gene duplication event in HDAC and a loss of one HAT gene in P. yezoensis . According to the conserved domains and phylogenetic analysis, they encoded three GCNA5-, one TAFII250- and one MYST-HAT, as well as five HDA1-and five SIRT-HDACs. The sirtuin-domain of Py06502 harbored a ~100 aa insert and interestingly, this insertion was specifically observed in Bangiales species. Two nuclear-localized HATs were transcriptionally up-regulated at the early stage of dehydration and so were two nuclear HDA1s when moderate dehydration started, suggesting their potential roles in modulating downstream gene expression to facilitate dehydration adaptation by changing histone acetylation patterns on relevant regulatory elements. This was experimentally confirmed by the increased decline in photosynthesis efficiency during dehydration when HAT and HDAC activities were inhibited by SAHA and MB-3, respectively. Transcriptional patterns of multiple dehydration-responsive genes after water loss were strongly affected by MB-3 or SAHA treatment. This study provides the first insight into the regulation and function of HAT/HDAC during stress adaptation in red algae.