A review of phycocyanin: Production, extraction, stability and food applications.

This paper aims to review the production, extraction, stability and food application of phycocyanin. Currently, light source modulation and organic solvent cultivation of high biomass phycocyanin is an important research direction. The development of nitrogen oxygen balanced system-assisted culture environments to raise production will become a trend, the green and sustainable characteristics of which compensate for the drawbacks of the former. Microfiltration, ultrafiltration, and ultrasonic cell rupture technologies address the drawbacks of solvent extraction and achieve a significant increase in purity. Biorefining technology may become the trend to achieve the highest purity and efficiency in large-scale production of phycocyanin. For the stability of phycocyanin, the development of complexes is a trend, but it should consider the suitability of the materials complex with them for production as foodstuffs. Phycocyanin is mainly developed as a natural pigment, and the main point is the coloring power and stability of natural pigments.

Hypoglycemic peptide preparation from Bacillus subtilis fermented with Pyropia: Identification, molecular docking, and in vivo confirmation.

Hypoglycemic foods have attracted increasing research interest. This study prepared a hypoglycemic product from Bacillus subtilis fermented with Pyropia (PBP), which has promising industrial potential, and elucidated its hypoglycemic mechanism. The aqueous PBP solution was orange, with protein as the main functional component. In vivo experiments demonstrated that PBP could increase insulin secretion and inhibit α-glucosidase activity, resulting in a hypoglycemic effect superior to that of acarbose at the same dose. Molecular docking revealed that the peptides APPVDID, GPPDSPY, PPSSPRP, and SPPPPPA from PBP could inhibit both α-glucosidase and dipeptidyl peptidase-IV (DPP-IV) activities. Pro residues promoted PBP peptide binding to the hydrophobic pocket S1 of DPP-IV. Additionally, PBP reduced inflammation and promoted the growth of beneficial gut bacteria (Prevotellaceae_UCG_003, Lachnospiraceae_UCG_001). This study presents a novel approach for the high-value utilization of Pyropia and a new option for the production of hypoglycemic functional foods and medicines.

Field and Laboratory Evidence That Chlorpyrifos Exposure Reduced the Population Density of a Freshwater Snail by Increasing Juvenile Mortality.

Pesticides have been frequently detected in global freshwater ecosystems, but attempts to document changes in population dynamics of organisms upon exposure to pesticides, establish a causal relationship between exposure and population effects, and identify the key toxic events within individuals under natural field conditions remain rare. Here, we used a field survey, a reciprocal cross-transplant experiment, and a laboratory toxicity experiment to build a compelling case that exposure to the insecticide chlorpyrifos was responsible for differences in snail (Bellamya aeruginosa) densities in eastern (ELL) and western basins of Liangzi Lake in China. Our field survey and reciprocal cross-transplant experiment revealed significant differences in snail densities, juvenile percentage, survival, and relative telomere length (RTL) in the two basins. The insecticide chlorpyrifos detected in snail tissues was negatively correlated with snail densities, the percentage of juvenile snails, and RTL and had an extremely high risk quotient in ELL. In the laboratory experiment, tissue concentrations of chlorpyrifos detected in ELL were associated with reduced RTL and increased juvenile mortality in B. aeruginosa. These results support the hypothesis that chlorpyrifos exposure in ELL reduced the density of snails by reducing juvenile survival and, consequently, recruitment to the adult population.

Toxic responses of environmental concentrations of bifenthrin in larval freshwater snail Bellamya aeruginosa.

Bifenthrin (BF) is ubiquitous in aquatic environments, and studies have indicated that environmental concentrations of BF could cause neurotoxicity and oxidative damage in fish and decrease the abundance of aquatic insects. However, little information is available on the toxicity of BF in freshwater benthic mollusks. Bellamya aeruginosa (B. aeruginosa) is a key benthic fauna species in aquatic ecosystems, and has extremely high economic and ecological values. In this study, larval B. aeruginosa within 24 h of birth were exposed to 0, 30 or 300 ng/L of BF for 30 days, and then the toxic effects from molecular to individual levels were comprehensively evaluated in all the three treatment groups. It was found that BF at 300 ng/L caused the mortality of snails. Furthermore, BF affected snail behaviors, evidenced by reduced crawling distance and crawling speed. The hepatopancreas of snails in the two BF exposure groups showed significant pathological changes, including increase in the number of yellow granules and occurrence of hemocyte infiltration, epithelial cell thinning, and necrosis. The levels of ROS and MDA were significantly increased after exposure to 300 ng/L BF, and the activities of two antioxidant enzymes SOD and CAT were increased significantly. GSH content decreased significantly after BF exposure, indicating the occurrence of oxidative damage in snails. Transcriptomic results showed that differentially expressed genes (DEGs) were significantly enriched in pathways related to metabolism and neurotoxicity (e.g., oxidative phosphorylation and Parkinson disease), and these results were consistent with those in individual and biochemical levels above. The study indicates that environmental concentration of BF results in decreased survival rates, sluggish behavior, histopathological lesions, oxidative damage, and transcriptomic changes in the larvae of B. aeruginosa. Thus, exposure of larval snails to BF in the wild at concentrations similar to those used in this study might have adverse consequences at the population level. These findings provide a theoretical basis for further assessing the ecological risk of BF to aquatic gastropods.

Organophosphorus flame retardants in fish from the middle reaches of the Yangtze River: Tissue distribution, age-dependent accumulation and ecological risk assessment.

Two fish species from the middle reaches of the Yangtze River, China, were sampled to investigate the occurrence, tissue distribution, age-dependent accumulation and ecological risk assessment of 24 organophosphorus flame retardants (OPFRs). Seventeen OPFRs were detected in tissue samples with a total concentration ranging from not detected (ND) to 1092 ng g-1 dw. Cl-OPFRs were predominant in all tissues (mean: 145 ng g-1 dw, median: 72.9 ng g-1 dw) and the concentrations of OPFRs in brain were the greatest (crucian carp: 525 ng g-1 dw, silver carp: 56.0 ng g-1 dw) compared with the other three organs (e.g., liver, muscle and gonad). Furthermore, the total concentrations of OPFRs in crucian carp tissues were significantly greater than those in silver carp (P < 0.01). Age-dependent accumulation of OPFRs was observed in the two fish species, but the accumulation profiles in the two fish species were different. Ecological risk assessment demonstrated that both fish species were at medium to high risk, and TDCIPP was a main contributor (>50%).

Identification and Verification of Novel Umami Peptides Isolated from Hybrid Sturgeon Meat (Acipenser baerii × Acipenser schrenckii).

To explore the umami mechanism in sturgeon meat, five peptides (ERRY, VRGPR, LKYPLE, VKKVFK, and YVVFKD) were isolated and identified by ultrafiltration, gel filtration chromatography, and UPLC-QTOF-MS/MS. The omission test confirmed that the five umami peptides contributed to the umami taste of sturgeon meat. Also, the peptides had the double effective role of enhancing both umami and saltiness. The threshold of ERRY was only 0.031, which exceeded most umami peptides in the last 3 years. Molecular docking results showed that five peptides could easily bind to Gly167, Ser170, and Try218 residues in T1R3 through hydrogen bonds and electrostatic interactions. Furthermore, molecular dynamics simulations indicated that hydrogen bonds and hydrophobic interactions were the main intermolecular interaction forces. This study could contribute to revealing the umami taste mechanism of sturgeon meat and provide new insights for effective screening of short umami peptides.

The Influence of Foreign Direct Investment on Physical Health of Rural-Urban Migrants-Empirical Evidence from China Migrants Dynamic Survey.

The purpose of this study is to explore the influence of Foreign Direct Investment (FDI) on rural-urban migrants' physical health and its influencing mechanism. A total of 134,920 rural-urban migrant samples are matched based on the China Migrants Dynamic Survey in 2017 and the China Urban Statistical Yearbook in 2016. On the basis of the samples, a Binary Probit Model is used to explore the relationship between the degree of FDI and rural-urban migrants' physical health. The results show that compared with migrants who lived in cities with a lower FDI level, rural-urban migrants who lived in cities with a higher FDI level are better in physical health. The results of the mediation effect model show that the degree of FDI has a significant positive impact on employment rights and benefits the protection of rural-urban migrants, improving rural-urban migrants' physical health, which means employment rights and benefits protection plays an intermediary role in the process of FDI affecting rural-urban migrants' physical health. Therefore, when formulating public policies such as plans to improve the physical health of rural-urban migrants, not only the availability of medical services for rural-urban migrants needs to be improved, but the positive spillover effect of FDI should be taken into account. By doing so, FDI can positively affect the physical health of rural-urban migrants.

Novel Peptide from the Hydrolysate of Hybrid Sturgeon (Acipenseridae) Spinal Cord: Isolation, Identification, and Anti-proliferative Effects in Human Cervix Cancer Cells.

Anti-proliferative peptides have recently attracted attention for their excellent bioactivity and biocompatibility. In this paper, five novel anti-proliferative peptides were identified from the hydrolysate of hybrid sturgeon spinal cord (HSSC). In addition, the structure-activity relationship of the novel anti-proliferative peptides was explored. In vitro experiments indicated that the peptide "VDSVLDVVRK" presented the highest inhibition of HeLa cell growth in all samples (IC50 = 2.5 µM). VDSVLDVVRK showed a random coil secondary structure and nanomicelles in the tumor microenvironment. Transmission electron microscopy results confirmed that nanomicelles disassemble as the concentration of VDSVLDVVRK decreases. Furthermore, VDSVLDVVRK could induce HeLa cell apoptosis by increasing the expression of Cyt-c (98.65 ± 1.85%, p < 0.01) and caspase-9 (39.85 ± 1.81%, p < 0.01). In this study, the anti-proliferative mechanism of the HSSC peptide was discussed, which provided a theoretical basis for the research and development of anti-proliferative functional food.

Application of agricultural pesticides in a peak period induces an abundance decline of metazoan zooplankton in a lake ecosystem.

The contamination of pesticides has been recognized as a major stressor in fresh water ecosystems in terms of the losses of services and population declines and extinctions. However, information on the adverse effects of pesticides on zooplankton communities under natural field conditions are still lacking, although zooplankton is quite sensitive to most of pesticides in laboratory studies. In this study, a natural lake ecosystem (Liangzi Lake) was used to determine the relationship between pesticide contamination and abundance decline of metazoan zooplankton. In August 2020, the comprehensive trophic level indexes and the abundance of phytoplankton in the 14 sampling sites of Liangzi Lake were comparable, but the abundance of metazoan zooplankton showed significant variations across two orders of magnitude. These results suggested that other factors, such as pesticide contamination, might be responsible for the variations of metazoan zooplankton community. Furthermore, the responsible pesticides were screened, and totally 29 pesticides were obtained. Finally, five pesticides were identified to provide more than 99.4% toxic contributions and chlorpyrifos and cypermethrin were two main causal agents. These results were further supported by laboratory exposure experiments using D. magna and field study in November 2020, where the concentrations of the 29 pesticides were strongly decreased and the abundance of metazoan zooplankton was comparable across the 14 sites of Liangzi Lake. Taken together, this work provided an evidence that the contamination of pesticides might be responsible for the abundance decline of metazoan zooplankton in a natural freshwater ecosystem.