Phycocyanin Research Articles

Phycocyanin-phlorotannin complexes improve the structure and functional properties of yogurt

Adding natural bioactive ingredients to yogurt can improve the nutritional and physiological benefits. In this study, we used ultrasonic-assisted phlorotannin from Ascophyllum nodosum (A. nodosum) modified phycocyanin (PC) to form a complex (UPP) to produce a fortified fermented yogurt. The effects of PC and UPP on the structure, stability, and function of fermented yogurt within 7 days were assessed using physicochemical properties, texture analysis, rheological testing, 16S rDNA sequencing analysis, and lipidomics analysis. Molecular docking indicated that PC might bind to phlorotannin via ARG-77, ARG-84, LEU-120, ALA-81, CYS-82, and ASP-85 sites.When the mass ratio of the complex is 1:1, the ability of UPP1:1 to remove DPPH· scavenging ability in an acid environment increased by about 50 %. UPP1:1 with more acid stability changed the microstructure of the yogurt, enhanced the stability of the yogurt, improved the antioxidant properties, and inhibited the growth of harmful bacteria within 7 days. This work encouraged the extraction and use of phlorotannin from edible brown algae and offered a straightforward method for making yogurt supplemented with PC.

Optimizing the Extraction of Bioactive Compounds from Porphyra linearis (Rhodophyta): Evaluating Alkaline and Enzymatic Hydrolysis for Nutraceutical Applications.

Porphyra sensu lato is one of the most economically significant and widely cultured and consumed algae in the world. Porphyra species present excellent nutraceutic properties due to their bioactive compounds (BACs). This research aimed to find the most efficient aqueous extraction method for BACs by examining alkaline and enzymatic hydrolysis. Alkaline hydrolysis with 2.5% sodium carbonate (SC) and at 80 °C proved optimal for extracting all BACs (phycobiliproteins, soluble proteins, polyphenols, and carbohydrates) except mycosporine-like amino acids (MAAs), which were best extracted with water only, and at 80 °C. Enzymatic hydrolysis, particularly with the 'Miura' enzymatic cocktail (cellulase, xylanase, glycoside hydrolase, and β-glucanase), showed superior results in extracting phycoerythrin (PE), phycocyanin (PC), soluble proteins, and carbohydrates, with increases of approximately 195%, 510%, 890%, and 65%, respectively, compared to the best alkaline hydrolysis extraction (2.5% SC and 80 °C). Phenolic content analysis showed no significant difference between the 'Miura' cocktail and 2.5% SC treatments. Antioxidant activity was higher in samples from alkaline hydrolysis, while extraction of MAAs showed no significant difference between water-only and 'Miura' treatments. The study concludes that enzymatic hydrolysis improves the efficiency of BACs extraction in P. linearis, highlighting its potential for the nutraceutical industry, and especially with respect to MAAs for topical and oral UV-photoprotectors.

Using urea-shifting to create a natural blue, antioxidant emulsifier from phycocyanin

Phycocyanin (PC) is an algae-derived blue protein that can serve as an antioxidant colorant and emulsifier. Urea was used as an emulsification aid by balancing PC's hydrophilic-lipophilic character and was removed by dialysis after emulsification processes. With increasing concentration, urea gradually dissociated and denatured the PC polymers. By using spectroscopic methods, the aromatic amino acids and chromophores appeared to fold inward, and the secondary helix structure devolved into the unordered structure. Structural changes caused the hydrophilic PC to become more hydrophobic, resulting in an increase of its emulsifying capacity with a concomitant cost to PC's natural blue color. The partially denatured PC increased the amount of PC surface adsorption at the O/W interface by 39.89% of adsorbing percentage and the O/W interfacial protein concentration was 1.56 mg m−2, resulting in finer and more dispersed emulsion droplets. Therefore, although the denaturation resulted in a partial weakening of the protein's antioxidant properties (from 7.70 to 5.54 nmol L−1 Trolox equivalent), the stabilized droplets allowed the emulsions to exhibit higher apparent antioxidant properties (from 7.80 to 7.87 nmol L−1 Trolox equivalent). In the 37 °C storage stability evaluation, emulsions with lower starting urea concentrations remained blue longer, while those with higher starting urea concentrations remained more stable to long-term storage and showed lower oxidation levels. The urea concentration of 5 M was chosen because it maintained a relatively stronger blue color while keeping the emulsion more stable and protecting the oils from further oxidation.

Synergistic modification of phycocyanin composite gel by xanthan gum and flaxseed gum and the fate during in vitro digestion

Phycocyanin (PC) belongs to the “blue food” protein, and its application exploration is of great significance in the food industry. In this study, the effects of different proportions of xanthan gum (XG) and flaxseed gum (FG) on the applicability of 3D printing, rheological properties, and the structural properties of PC were studied, and the interaction and in vitro digestion properties were also discussed. In the composite gel, PC concentration [0.1% (w/v)] and blend concentration (5 wt%) were fixed, but the ratio of XG to FG was different (5:0–0:5). With the increase of FG content, the 3D printing performance of the gel was improved, and the rheological properties and texture properties were also changed. The molecular interaction between PC and XG/FG was hydrogen bonding and hydrophobic interactions. In addition, PC-XG/FG gels after in vitro digestion had better ability to remove hydroxyl free radicals. In summary, the study offered theoretical direction for the use of two polysaccharides to synergistic modification of the functional factors to improve stability. Furthermore, it provided guidance on how to improve the nutritional value of 3D-printed samples.

Phycocyanin-based rapid fluorometric immunoassay for the determination of aflatoxin B1, deoxynivalenol, and zearalenone in food and feed matrices

This study presents a new multiplex lateral flow immunoassay (LFIA) for the detection of aflatoxin B1 (AFB1), deoxynivalenol (DON), and zearalenone (ZEN). The multi-LFIA utilized phycocyanin (PC), a protein with excellent photophysical properties, as a fluorescent indicator for quantifying the three mycotoxins on a lateral flow strip platform. PC and monoclonal antibodies (mAbs) against AFB1, DON, and ZEN were immobilized onto carboxylated latex nanospheres (LNS) through a one-step coupling process. The resulting conjugates with strong red fluorescence were then used for multiplex sensing of AFB1, DON, and ZEN in wheat, corn, and animal feed. The visual results of the assay were obtained using LED UV lights coupled with a smartphone in less than 25 min. Under the optimal conditions, the new multi-LFIA achieved minimum detection limits of 1.04, 1.6, and 2.08 ng/mL for AFB1, 2.2, 6.45, and 2.9 ng/mL for DON, and 1.74, 1.67, and 2.11 ng/mL for ZEN in wheat, corn, and feed, respectively. The proposed method demonstrated high selectivity for AFB1, DON, and ZEN and showed strong correlation with LC-MS/MS results in spiked samples. In summary, the proposed method is feasible, rapid, and could serve as a highly sensitive platform for detecting AFB1, DON, and ZEN and other analytes in a single format.

Effect of dietary Arthrospira platensis phycocyanin on broiler chicken growth performance, physiological status, fatty and amino acid profiles.

Natural antioxidants are crucial for preserving and enhancing the health, survival, reproduction, and reproductive function of poultry. Phycocyanin (PC) is a natural blue food colorant with various health benefits. The aim of this study was to extract Arthrospira platensis phycocyanin (ApPC) from A. platensis using simple and economical methods and investigate the impact of phytocyanin supplementation on the performance and fatty and amino acid profiles of broiler chicks. PC was extracted from A. platensis by freezing and thawing, and optimization conditions such as pH and temperature were applied during storage periods. A total of 270 1-week-old Ross breed broiler chicks were randomly assigned to the following three treatment groups: basal diet supplemented with 0 mg of PC/kg diet (control), basal diet supplemented with 1 g PC/kg diet (T1), and basal diet supplemented with 2 g PC/kg (T2). In a completely randomized design, three cage replicates (30 birds each) were assigned to each of the three groups. The dietary effects of ApPC on growth performance (body weight gain [BWG], body weight [BW], feed intake, feed conversion ratio, serum constituents, and antioxidant indices) in broiler chickens, free amino acids, and fatty acids in muscles were evaluated. Total BWG and BW increased without a significant effect on the total feed consumption. Serum levels of total proteins and albumin increased with increasing ApPC supplementation. In addition, globulin levels significantly increased. There was a significant decrease in serum total cholesterol levels among the treatments. The activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione, and total antioxidant capacity) is significantly increased. In contrast, an increase in ApPC caused a significant decrease in malondialdehyde. The content and quantity of fatty acids and amino acids in the meat of broiler chicks supplemented with PC varies. The addition of PC to broiler chicken diets enhances antioxidant activities, BW, BWG, and meets quality requirements.

Characterization of emulgels formulated with phycocyanin and diutan gum as a novel approach for biocompatible delivery systems

Phycocyanin (PC), a protein derived from algae, is non-toxic and biocompatible. Due to its environmental and sustainable properties, it has been studied as an alternative stabilizer for food emulsions. In this sense, the main objective of this work is to evaluate the effectiveness of PC and its use in combination with diutan gum (DG), a biological macromolecule, to prepare emulgels formulated with avocado oil. Z-potential measurements show that the optimum pH for working with PC is 2.5. Furthermore, the system exhibited a structured interface at this pH. The surface tension did not decrease further above 1.5 wt% PC. Interestingly, emulsions formulated with >1.5 wt% PC showed recoalescence immediately after preparation. Although 1.5 wt% had the smallest droplet size, this emulsion underwent creaming due to the low viscosity of the system. DG was used in combination with PC to increase viscosity and reduce creaming. As little as 0.1 wt% DG was sufficient to form an emulgel when incorporated into the previous emulsion, which exhibited pseudoplastic behaviour and viscoelastic properties with very low creaming rates. However, the use of PC in combination with DG resulted in a non-aggregated and stable emulgel with 1.5 wt% PC and 0.1 wt% DG.

In vitro antibiofilm effect of different irradiation doses in infected root canal model

BackgroundEradication of endodontic biofilms from the infected root canal system is still the main concern in endodontics. In this study, the role of the power density parameter in the efficacy of antimicrobial photodynamic therapy (PDT) with toluidine blue O (TBO) and phycocyanin (PC) activated by a 635 nm diode laser (DL) against Enterococcus faecalis biofilm in the root canal model was investigated. Materials and methodsThe E. faecalis biofilm in the root canal was treated with TBO and PC with different power densities (636, 954, 1273, and 1592 W/cm2). The untreated biofilm represented the control group. After the treatments, the biofilms were analyzed based on the number of colonies per milliliter. ResultsTBO and PC activated with 635 nm DL with a power density of 1592 W/cm2 were more efficient in removing E. faecalis biofilms within the root canals than those with a power density of 636 W/cm2 (p = 0.00). ConclusionThe light power density optimized the bacterial reduction of E. faecalis biofilms in the root canal spaces. These results provide information on the decisive parameters for performing PDT on intracanal biofilms.

Effects of the algae derivatives on performance, intestinal histomorphology, ileal microflora, and egg yolk biochemistry of laying Japanese quail

We examined the effect of the Persian Gulf algae derivates, phycocyanin (PC) and fucoidan (FUC), on production performance, egg quality, intestinal histomorphology, ileal microflora, and egg yolk biochemistry of laying Japanese quail. A total of 250 six-wk-old Japanese quails with an average body weight of 215 ± 10 g were allocated to 5 treatments, 5 replicates and 10 birds in each replicate in a completely randomized design. The treatment groups received PC (from Spirulina platensis) and FUC (from brown seaweed) in their drinking water while control groups did not. Treatment groups received PC and FUC at 20 or 40 mg/L levels (denoted as PC20, PC40, FUC20, and FUC40, respectively). All birds were fed the same diet. All treatments significantly improved the percentage of hen day egg production (HDEP) (P = 0.002), egg mass (P = 0.002), and feed conversion ratio (FCR) (P = 0.022) but no difference was noted in egg weight (EW) and feed intake (FI). Different levels of PC and FUC significantly increased the thickness of eggshells (P = 0.022); however, the weight of the digestive tract (liver, spleen, proventriculus, gizzard, and pancreas) and oviduct was not affected. Algal derivates improved the villus height (P = 0.007) and crypt depth (P = 0.007) of the duodenum, as well as, the villus height (P = 0.005) and crypt depth (P = 0.026) of the jejunum. Both algal derivates positively affected the intestinal microflora (populations of Lactobacillus (P = 0.017), Coliform (P = 0.005), and Clostridium (P = 0.000)) whereas aerobic bacteria were unaffected. Yolk cholesterol P = 0.012) and yolk malondialdehyde P = 0.050) content were significantly reduced in experimental treatments compared to the control group. In conclusion, our results showed that the treatment of laying Japanese quails with algal derivates positively affects quail performance, intestinal morphology, intestinal microflora, and yolk cholesterol and malondialdehyde. Additional studies exploring optimal dosages and mechanisms of action is warranted to fully understand the scope of the algae derivates in poultry production.

Novel Effects of Phycocyanin Extract on the Regulation of Apoptosis Genes in Human Colorectal Cancer Cells

Background: Cancer is a major cause of death worldwide, second only to cardiovascular disease. Many factors influence the development of cancer, including environmental, genetic, and lifestyle factors. Although the prognosis of colon cancer treatment has improved significantly in recent years, there is still much clinical need to explore new treatment strategies with anticancer and immune-enhancing effects. Phycocyanin (PC) is an important compound isolated from blue-green algae and a well-known antioxidant that suppresses oxidative reactions in cells. It also has other useful functions, such as high efficiency, low toxicity, and antitumor properties. We investigated the potential antiapoptotic effect of PC in vitro on human normal and cancer cell lines. Methods: Phycocyanin extracted from Streptomyces platensis algae has the potential to become a turning point in pharmaceutical research. In this study, PC was used as a natural anticancer agent and apoptosis activator to increase the expression of the PTEN and Bax genes in HT-29 cancer and normal cells (HUVEC). The effect of treatment with PC was evaluated using an MTT assay and flow cytometry. Results: The results showed that PC can have apoptotic effects on the human colon cancer cell line (HT-29) by up-regulating PTEN and Bax genes and down-regulating AKT and BCL-2 genes. Conclusion: Based on the findings, PC can be considered a herbal treatment and a useful supplement in the management of human colorectal cancer.

Studying the impact of phycoerythrin on antioxidant and antimicrobial activity of the fresh rainbow trout fillets

Marine cyanobacteria present a significant potential source of new bioactive compounds with vast structural diversity and relevant antimicrobial and antioxidant activities. Phycobiliproteins (PBPs) like phycocyanin (PC), phycoerythrin (PE), and water-soluble cyanobacterial photosynthetic pigments, have exhibited strong pharmacological activities and been used as natural food additives. In this study, phycoerythrin (PE) isolated from a marine strain of cyanobacterium Nostoc sp. Ft salt, was applied for the first time as a natural antimicrobial as well as an antioxidant to increase the shelf life of fresh rainbow trout i.e., (Oncorhynchus mykiss) fillets. Fresh trout fillets were marinated in analytical grade PE (3.9 μg/mL) prepared in citric acid (4 mg/mL), and stored at 4 °C and 8 °C for 21 days. Microbiological analysis, antioxidant activity and organoleptic evaluation of both control and treated fish fillets were then statistically compared. The results demonstrated noticeable (P < 0.05) differences in the microbial counts, antioxidant activity, and organoleptic characteristic values between PE-treated and non-treated groups. In addition, we observed that treating fresh fish fillets with a PE solution leads to a significant increase in shelf life by at least 14 days. Consequently, PE could be an alternative to synthetic chemical additives since it does not contain the potentially dangerous residues of the synthetic chemical additives and is thus healthier to the consumers.

Cross-Linked Hyaluronan Derivatives in the Delivery of Phycocyanin.

An easy and viable crosslinking technology, based on the "click-chemistry" reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (click-crosslinking), was applied to graft copolymers of medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted with ferulic acid (FA) residues bearing clickable propargyl groups, as well as caffeic acid derivatives bearing azido-terminated oligo(ethylene glycol) side chains. The obtained crosslinked materials were characterized from the point of view of their structure and aggregation liability to form hydrogels in a water environment. The most promising materials showed interesting loading capability regarding the antioxidant agent phycocyanin (PC). Two novel materials complexes (namely HA(270)-FA-TEGEC-CL-20/PC and HA(270)-FA-HEGEC-CL-20/PC) were obtained with a drug-to-material ratio of 1:2 (w/w). Zeta potential measurements of the new complexes (-1.23 mV for HA(270)-FA-TEGEC-CL-20/PC and -1.73 mV for HA(270)-FA-HEGEC-CL-20/PC) showed alterations compared to the zeta potential values of the materials on their own, suggesting the achievement of drug-material interactions. According to the in vitro dissolution studies carried out in different conditions, novel drug delivery systems (DDSs) were obtained with a variety of characteristics depending on the desired route of administration and, consequently, on the pH of the surrounding environment, thanks to the complexation of phycocyanin with these two new crosslinked materials. Both complexes showed excellent potential for providing a controlled/prolonged release of the active pharmaceutical ingredient (API). They also increased the amount of drug that reach the target location, enabling pH-dependent release. Importantly, as demonstrated by the DPPH free radical scavenging assay, the complexation process, involving freezing and freeze-drying, showed no adverse effects on the antioxidant activity of phycocyanin. This activity was preserved in the two novel materials and followed a concentration-dependent pattern similar to pure PC.

P116 Gastro-resistant microparticles for the oral delivery of Phycocyanin in the Inflammatory Bowel Disease therapy

Abstract Background Inflammatory Bowel Disease (IBD) is a chronically relapsing inflammation of the gastrointestinal tract, with ambiguous etiology. Oral route is the most common and acceptable approach for drug administration in the IBD treatment. However, it remains a challenge to maintain the stability of the drugs during oral treatment, particularly in the gastric environment, due its harsh conditions. In this context, the antioxidant and antiinflagmmatory properties of various natural compounds, as Phycocyanin (PC), a water-soluble bioactive molecule found in algae, can be strongly affected by factors as pH and temperature, inducing PC degradation and attenuating the curative effects. In this work, we produced a gastro-resistant microparticles (MPs) as controlled release systems for PC, and we aimed to compare its efficacy with free PC effects, on rat model of IBD. Methods The novel pharmaceutical system (SPC) was produced by microencapsulation technique, the spray-drying technique, using soy proteins (SPs) as natural excipients, aiming to improve the stability of the active ingredient and to ensure a modified release profile of PC. Rats were divided into groups and colitis was induced by intracolonic instillation of Dinitrobenzene sulfonic acid (DNBS, 20 mg/rat). Effects of preventive oral treatment of free PC or SPC were investigated, bioavailability was assessed and then body weight loss, stool consistency, colon weight/length index, myeloperoxidase activity (MPO), macroscopic damage and disease activity index (DAI) were determined. Results The SPC microparticle systems showed enhanced bioavailability of Phycocyanin, resulting in increased blood concentrations. The SPC system achieved the maximum AUC value and a modified release profile, particularly for gastro-resistant types, with a delayed Tmax of 5 hours, indicating their potential as a gastro-resistant formulation. Both PC and SPC pretreatments significantly ameliorated the severity of DNBS-induced colitis, however SPC pretreatment demonstrated enhanced activity vs PC. SPC rats showed a reduction of DAI, body weight loss and diarrhea incidence &amp;gt;15%, compared to PC (P&amp;lt;0.05); the ability of preventing the DNBS-induced macroscopic colonic damage and the MPO increase in SPC group were significantly higher than PC group (P&amp;lt;0.05) and also a tendency to improvement of colon weight/length index was observed. Conclusion In conclusion, the results of our research demonstrated that gastro-resistant microparticles (SPC) exhibit significantly improved therapeutic efficacy compared to orally administered free PC and can be developed as an effective new oral drug delivery system with controlled release profile in the treatment of IBD.

Customized development of 3D printed anthocyanin-phycocyanin polychromatic oral film via chondroitin sulfate homeostasis: A platform based on starch and κ-carrageenan

The development of oral film with diverse colors and customized nutrition is in line with the innovation of emerging food. In this study, polychromatic system was formed by regulating the ratio of phycocyanin (PC) to blueberry anthocyanin (BA). Further, chondroitin sulfate (CS) was utilized to achieve color-enhanced and homeostatic effects on PC-BA, and κ-carrageenan (KC) - starch complex was exploited as printing ink to construct oral film system. The color-enhanced effect of CS is mainly related to the complexation of sulfate groups, and the film-forming substrates are combined mainly through hydrogen bonding. In addition, the proportion of KC modulated the gel structure of printing ink, and affected 3D printability and physical properties of oral film. OF II (1.5 % KC content) had a uniform and dense network structure, with the most stable color and the highest BA retention (70.33 %) after 8 d of light exposure. Importantly, OF II had an excellent slow-release effect, and BA release rate was as high as 92.52 %. The optimized components can form polychromatic oral film with controllable color and structure, and provide new insights for the creation of sensory personalized and nutritionally customized food.

UVB irradiation improved the gel properties of phycocyanin‐undaria pinnatifida hydrogel

SummaryRich in numerous nutrients, undaria pinnatifida (UP) exhibited a broad spectrum of biological properties, including anti‐inflammatory, anti‐bacterial, anti‐cancer, and antioxidant properties. A sexual pigment protein complex known as phycocyanin (PC) was the perfect photosensitiser and had no negative effects. Due to their superior qualities, hydrogels were also widely employed in tissue engineering, medication administration, and food packaging at the same time. The aim of this work was to investigate the impact of UVB irradiation on the gel characteristics of PC‐UP hydrogels using UVB irradiation technology rather than chemical crosslinking approach. The results showed that the G′ value of PC‐UP hydrogel increased from 114.17 ± 0.58 Pa to 156.72 ± 0.82 Pa and the G″ value increased from 36.80 ± 0.79 Pa to 58.05 ± 1.06 Pa after UVB irradiation. At the same time, the texture properties of hydrogel were significantly improved, and the hardness, adhesion and chewiness were increased to 214.02 ± 3.85, 198.51 ± 4.25 and 195.81 ± 5.69, respectively. After UVB irradiation, hydrogen bond was formed in PC‐UP hydrogel to improve its thermal stability. In conclusion, the results show that PC decomposes with alginic acid, potassium salt, and sodium salt in UP under UVB irradiation to form a gel network structure, which enhances its gel properties. This study provides guidance for the photo response of PC‐UP hydrogels, provides ideas for the application of PC‐UP hydrogels, and broadens the application field of future hydrogels.

Formulation and Characterization of Sustainable Algal-Derived Nanoemulgels: A Green Approach to Minimize the Dependency on Synthetic Surfactants.

Phycocyanin (PC), a natural protein that is very interesting from the medical point of view due to its potent antioxidant and anti-inflammatory properties, is obtained from algae. This compound is gaining positions for applications in the food industry. The main objective of this work was to obtain nanoemulgels formulated with PC and k-carrageenan (a polymer that is obtained from algae as well). An optimization of the processing parameters (homogenization pressure and number of cycles) and the ratio of PC and a well-known synthetic surfactant (Tween 80) was developed using response surface methodology. The results of this optimization were 25,000 psi, seven cycles, and a 1:1 ratio of PC/Tween80. However, the necessity for the incorporation of a polymer that plays a thickener role was observed. Hence, k-carrageenan (k-C) was used to retard the creaming process that these nanoemulsions suffered. The incorporation of this biopolymer provoked the creation of a network that showed gel-type behavior and flow indexes very close to zero. Thanks to the combined use of these two sustainable and algae-obtained compounds, stable nanoemulgels were obtained. This work has proved that the combined use of PC and k-C has emerged as a sustainable alternative to stabilize dispersed systems for the food industry.

Therapeutic effect of phycocyanin on chronic obstructive pulmonary disease in mice

IntroductionThe prevention and treatment of chronic obstructive pulmonary disease (COPD) is closely tied to antioxidation and anti-inflammation. Phycocyanin (PC) has numerous pharmacological effects, such as antioxidation and anti-inflammation. However, it remains unclear whether PC can play a therapeutic role in COPD. ObjectiveAs inflammation and oxidative stress can aggravate COPD, this study is to explore the effect of PC on COPD mice and its mechanisms. MethodsThe COPD mice model was established by exposing them to lipopolysaccharide (LPS) and cigarette smoke (CS); PC was administrated in a concentration of 50 mg/kg for 30 days. On the last day, lung function was measured, and bronchoalveolar lavage fluid (BALF) was obtained and classified for cells. Lung tissue pathological change was analyzed, and organ indices statistics were measured. Based on molecular docking, the mechanism was explored with Western blotting, immunohistochemical, and immunofluorescence in vivo and in vitro. ResultsPC significantly ameliorated the pulmonary function of COPD mice and reduced inflammation of the lung (p < 0.05), and hematoxylin and eosin (H&E) staining showed PC depressed lung inflammatory cell accumulation and emphysema. Periodic acid Schiff (PAS) and Masson staining revealed that PC retarded goblet cells metaplasia and collagen deposition (p < 0.05). In addition, in vivo PC regulated Heme oxygenase 1 (HO-1) (p < 0.05) and NAD(P)H dehydrogenase quinone 1 (NQO1) level (p < 0.01) in the lung, as well as NOX2 level in pulmonary macrophages. Molecular docking results indicate that phycocyanobilin (PCB) in PC had a good binding site in Keap1 and NOX2 proteins; the phycocyanobilin-bound phycocyanin peptide (PCB-PC-peptide) was obtained for further studies. In vitro, PCB-PC-peptide could depress the phospho-NF-E2-related factor 2 (p-Nrf2) and NQO1 protein expression in RAW264.7 cells induced by cigarette smoke extract (CSE) (p < 0.05). ConclusionPC exerts beneficial effects on COPD via anti-inflammatory and antioxidative stress, which may be achieved through PCB.

Exploring marine algae-derived phycocyanin nanoparticles as a safe and effective adjuvant for sunscreen systems

BackgroundUV radiation (UV) exposure risks skin damage and cancer due to DNA damage and oxidative stress. Synthetic chemical sunscreens that protect against UV radiation can have health and environmental concerns. This study explores phycocyanin (PC), a marine algae-derived natural photoprotective compound, and its crosslinked nanoparticles (PCNP) as safe and effective adjuvants for sunscreen systems.MethodsPCNP was synthesized via genipin-crosslinking. PC and PCNP biocompatibility were assessed on mouse embryonic fibroblast cells. ABTS evaluated antioxidant activity, and the UV absorption capacity of PC and PCNP were analyzed. PCNP skin permeability was tested in vitro and in vivo. Gel formulations with PCNP were examined for UV absorption effects.ResultsPCNP showed good biocompatibility, maintaining cell viability above 90% across concentrations. Both PC and PCNP demonstrated concentration-dependent antioxidant activity, efficiently scavenging free radicals. PCNP exhibited enhanced UV absorption in the UVB range compared to PC alone. Skin permeation studies displayed limited PCNP penetration through skin layers. In vivo, absorption assessments indicated PCNP localized mainly in the stratum corneum. PCNP-containing gels displayed improved UV absorption compared to gels without PCNP.ConclusionThis study showcases PCNP’s potential as a natural and safe adjuvant for sunscreen with enhanced UV protection capabilities. PCNP preserved antioxidant activity, displayed limited skin penetration, and enhanced UV absorption. The findings suggest PCNP’s promise as a viable alternative to synthetic sunscreen agents, delivering effective photoprotection while minimizing health and environmental concerns.

Expanding the toolbox for phycobiliprotein assembly: phycoerythrobilin biosynthesis in Synechocystis

AbstractPhycobiliproteins (PBPs) play a vital role in light harvesting by cyanobacteria, which enables efficient utilization of photon energy for oxygenic photosynthesis. The PBPs carry phycobilins, open‐chain tetrapyrrole chromophores derived from heme. The structure and chromophore composition of PBPs is dependent on the organism's ecological niche. In cyanobacteria, these holo‐proteins typically form large, macromolecular antenna complexes called phycobilisomes (PBSs). The PBS of Synechocystis sp. PCC 6803 (hereafter Synechocystis) consists of allophycocyanin (APC) and phycocyanin (PC), which exclusively harbor phycocyanobilin (PCB) as a chromophore. Investigations into heterologous PBP biosynthesis in E. coli have proven limiting with respect to PBP assembly and their functional characterization. Consequently, we wanted to engineer a platform for the investigation of heterologously produced PBPs, focusing on unusual, phycoerythrobilin (PEB)‐containing light‐harvesting proteins called phycoerythrins (PEs) in Synechocystis. As a first step, a gene encoding for the synthesis of the natural cyanobacterial chromophore, PEB, was introduced into Synechocystis. We provide spectroscopic evidence for heterologous PEB formation and show covalent attachment of PEB to the α‐subunit of PC, CpcA, by HPLC and LC–MS/MS analyses. Fluorescence microscopy and PBS isolation demonstrate a cellular dispersal of PBPs with modified phycobilin content. However, these modifications have minor effects on physiological responses, as demonstrated by growth rates, oxygen evolution, nutrient accumulation, and PBP content analyses. As a result, Synechocystis demonstrates the capacity to efficiently manage PEB biosynthesis and therefore reflects a promising platform for both biochemical and physiological investigations of foreign and unusual PEs.

Deep learning-based efficient drone-borne sensing of cyanobacterial blooms using a clique-based feature extraction approach

Recent advances in remote sensing techniques provide a new horizon for monitoring the spatiotemporal variations of harmful algal blooms (HABs) using hyperspectral data in inland water. In this study, a hierarchical concatenated variational autoencoder (HCVAE) is proposed as an efficient and accurate deep learning (DL) based bio-optical model. To demonstrate its usefulness in retrieving algal pigments, the HCVAE is applied to bloom-prone regions in Daecheong Lake, South Korea. By abstracting the similarity between highly related features using layer-wise clique-based latent-feature extraction, HCVAE reduces the computational loads in deriving outputs while preventing performance degradation. Graph-based clique-detection uses information theory-based criteria to group the related reflectance spectra. Consequently, six latent features were extracted from 79 spectral bands to consist of a multilevel hierarchy of HCVAE that can simultaneously estimate concentrations of chlorophyll-a (Chl-a) and phycocyanin (PC). Despite the parsimonious model architecture, the Chl-a and PC concentrations estimated by HCVAE closely agree with the measured concentrations, with test R2 values of 0.76 and 0.82, respectively. In addition, spatial distribution maps of algal pigments obtained from HCVAE using drone-borne reflectance successfully capture the blooming spots. Based on its multilevel hierarchical architecture, HCVAE can provide the importance of latent features along with their individual wavelengths using Shapley additive explanations. The most important latent features covered the spectral regions associated with both Chl-a and PC. The lightweight neural network DNNsel, which uses only the spectral bands of highest importance in latent-feature extraction, performed comparably to HCVAE. The study results demonstrate the utility of the multilevel hierarchical architecture as a comprehensive assessment model for near-real-time drone-borne sensing of HABs. Moreover, HCVAE is applicable to a wide range of environmental big data, as it can handle numerous sets of features.