Bioanalytical approaches for the detection, characterization, and risk assessment of micro/nanoplastics in agriculture and food systems.

This review discusses the most recent literature (mostly since 2019) on the presence and impact of microplastics (MPs, particle size of 1 µm to 5 mm) and nanoplastics (NPs, particle size of 1 to 1000 nm) throughout the agricultural and food supply chain, focusing on the methods and technologies for the detection and characterization of these materials at key entry points. Methods for the detection of M/NPs include electron and atomic force microscopy, vibrational spectroscopy (FTIR and Raman), hyperspectral (bright field and dark field) and fluorescence imaging, and pyrolysis-gas chromatography coupled to mass spectrometry. Microfluidic biosensors and risk assessment assays of MP/NP for in vitro, in vivo, and in silico models have also been used. Advantages and limitations of each method or approach in specific application scenarios are discussed to highlight the scientific and technological obstacles to be overcome in future research. Although progress in recent years has increased our understanding of the mechanisms and the extent to which MP/NP affects health and the environment, many challenges remain largely due to the lack of standardized and reliable detection and characterization methods. Most of the methods available today are low-throughput, which limits their practical application to food and agricultural samples. Development of rapid and high-throughput field-deployable methods for onsite screening of MP/NPs is therefore a high priority. Based on the current literature, we conclude that detecting the presence and understanding the impact of MP/NP throughout the agricultural and food supply chain require the development of novel deployable analytical methods and sensors, the combination of high-precision lab analysis with rapid onsite screening, and a data hub(s) that hosts and curates data for future analysis.

Advances in Algin and Alginate-Hybrid Materials for Drug Delivery and Tissue Engineering.

In this review, we aim to provide a summary of recent research advancements and applications of algin (i.e., alginic acid) and alginate-hybrid materials (AHMs) in medical fields. Algin/alginate are abundant natural products that are chemically inert and biocompatible, and they have superior gelation properties, good mechanical strengths, and biodegradability. The AHMs have been widely applied in wound dressing, cell culture, tissue engineering, and drug delivery. However, medical applications in different fields require different properties in the AHMs. The drug delivery application requires AHMs to provide optimal drug loading, controlled and targeted drug-releasing, and/or visually guided drug delivery. AHMs for wound dressing application need to have improved mechanical properties, hydrophilicity, cell adhesion, and antibacterial properties. AHMs for tissue engineering need improved mechanical properties that match the target organs, superior cell affinity, and cell loading capacity. Various methods to produce AHMs that meet different needs were summarized. Formulations to form AHMs with improved stability, drug/cell-loading capacity, cell adhesion, and mechanical properties are active research areas. This review serves as a road map to provide insights into the strategies to develop AHMs in medical applications.

Gastrointestinal digestion and absorption characterization in vitro of zinc-chelating hydrolysate from scallop adductor (Patinopecten yessoensis).

BACKGROUD: Zinc (Zn) is an essential catalytic element in the human health system but its absorption in the intestinal system can be strongly affected by gastrointestinal (GI) digestion. In this study, the food-derived potential Zn carrier, scallop adductor hydrolysates (SAHs), was produced and characterized. RESULTS: During temporary storage at 4 °C, SAH decreased in Zn-chelating capacity in the aqueous phase, whereas the SAH-Zn complex exhibited high stability. Moreover, the secondary structure of SAH had no significant alteration. Zn morphologically altered the surface structures of SAH, which was involving in carboxyl group of SAH. Results of in vitro GI digestion suggested that the SAH-Zn maintained good stability in GI system and only proportion of high molecular weight cleaved. In addition, SAH could successfully carry and transport Zn while the fluorescence staining revealed free Zn accumulation inside the tissue. Finally, three representative absorbed peptides (around 600 Da) were identified and synthesized. Three synthetic peptides exhibit higher Zn-chelating capacity than SAH and could also successfully transported through the intestine. CONCLUSION: This study provided a theoretical basis for the investigation of digestion and absorption of marine animal-derived peptides as Zn carriers. © 2021 Society of Chemical Industry.

Characterization of a synthetic zinc-chelating peptide from sea cucumber (Stichopus japonicus) and its gastrointestinal digestion and absorption in vitro.

BACKGROUND: Zinc absorption in intestinal system could be strongly affected by the gastrointestinal digestion and absorption of zinc-chelating peptides serving as zinc carriers. In this study, a novel zinc-chelating sea cucumber synthetic peptide (SCSP) was synthesized to estimate its gastrointestinal digestion and promotive effect of zinc absorption in vitro. RESULTS: Analysis of isothermal titration calorimetry suggested that the binding of SCSP and zinc (N ≈ 1) was exothermic, with relatively weak binding affinity (K = 1.0 × 10-3  mol L-1 ). The formation of SCSP-Zn complexes brought morphological changes to the peptides confirmed by scanning electron microscopy (SEM), which also indicated 6.88% of the existence of zinc element. In addition, the SCSP-Zn complexes remained stable under simulated human gastrointestinal digestion. In an in vitro study, the SCSP-Zn complex could successfully transport through the intestinal membrane in the model of everted rat gut sacs (nearly 7.5 µM cm-2 ) as well as Caco-2 cells where the zinc transport reached 0.0014 mg mL-1 carried by SCSP. Fluorescence staining experiments revealed free zinc accumulation inside the tissues and cells treated with the SCSP-Zn complex. CONCLUSIONS: The chelation SCSP-Zn had the promotion ability of zinc absorption in vitro and ex vivo experiments, which suggested a theoretical basis for the design and production of effective zinc chelating peptides as zinc carriers to improve zinc bioavailability. © 2022 Society of Chemical Industry.

Extraction and Nano-Sized Delivery Systems for Phlorotannins to Improve Its Bioavailability and Bioactivity.

This review aims to provide an informative summary of studies on extraction and nanoencapsulation of phlorotannins to improve their bioavailability and bioactivity. The origin, structure, and different types of phlorotannins were briefly discussed, and the extraction/purification/characterization methods for phlorotannins were reviewed, with a focus on techniques to improve the bioactivities and bioavailability of phlorotannins via nano-sized delivery systems. Phlorotannins are promising natural polyphenol compounds that have displayed high bioactivities in several areas: anticancer, anti-inflammation, anti-HIV, antidiabetic, and antioxidant. This review aims to provide a useful reference for researchers working on developing better utilization strategies for phlorotannins as pharmaceuticals, therapeuticals, and functional food supplements.

Fucoxanthin@Polyvinylpyrrolidone Nanoparticles Promoted Oxidative Stress-Induced Cell Death in Caco-2 Human Colon Cancer Cells.

Fucoxanthin (FX), a natural carotenoid found in seaweed with multiple functional activities, is unstable with a poor water solubility that limits its utilization. This study aimed to improve FX's stability and bioavailability via the nano-encapsulation of FX in polyvinylpyrrolidone (PVP)-coated FX@PVP nanoparticles (NPs). The FX@PVP NPs were evaluated in terms of their morphology, stability, encapsulation efficiency (EE), loading capacity (LC), and in vitro release to optimize the encapsulation parameters, and a 1:8 FX:PVP ratio was found to perform the best with the highest EE (85.50 ± 0.19%) and LC (10.68 ± 0.15%) and improved FX stability. In addition, the FX@PVP NPs were shown to effectively deliver FX into Caco-2 cancer cells, and the accumulation of FX in these cancer cells showed pro-oxidative activities to ameliorate H2O2-induced damage and cell death. The FX@PVP NPs could potentially become a new therapeutical approach for targeted cancer treatment.

Synergistic effects of UVA irradiation and phlorotannin extracts of Laminaria japonica on properties of grass carp myofibrillar protein gel.

BACKGROUND: Oxidized phlorotannin can be used as a protein crosslinking agent to produce high-quality fish gel products. Phlorotannin can be easily induced to form quinone compounds in an oxidizing environment, while o-quinone has been proven to be a reactive, electrophilic intermediate that easily reacts with proteins to form rigid molecular crosslinking networks. The objective of this study was to investigate the synergistic effects of ultraviolet A (UVA) irradiation (1 h, 15 W m-2 ) and various concentrations of Laminaria japonica phlorotannin extracts (PTE) on the gel properties of grass carp myofibrillar protein (MP). RESULTS: UVA treatment and PTE could synergistically improve the MP gel properties more than PTE alone (P < 0.05). At 625 mmol kg-1 MP PTE alone, the gel strength and cooking yield reached 3.10 ± 0.16 g cm and 47.45 ± 0.35%, respectively, while with the same level of PTE plus UVA they became 4.26 ± 0.19 g cm and 53.89 ± 1.54%, respectively. The three-dimensional network structure of the gel (with PTE + UVA) showed higher connectivity and tightness than that of the control group (no treatment). CONCLUSIONS: The synergistic effects of PTE and UVA could effectively induce crosslinking of grass carp MP, which could lead to an improvement of MP gel quality. These findings would provide a new technical approach to produce high-quality protein gel products in the fish processing industry. © 2020 Society of Chemical Industry.

Preparation, Characterization and Antioxidant Activities of Kelp Phlorotannin Nanoparticles.

Phlorotannins are a group of major polyphenol secondary metabolites found only in brown algae and are known for their bioactivities and multiple health benefits. However, they can be oxidized due to external factors and their bioavailability is low due to their low water solubility. In this study, the potential of utilizing nanoencapsulation with polyvinylpyrrolidone (PVP) to improve various activities of phlorotannins was explored. Phlorotannins encapsulated by PVP nanoparticles (PPNPS) with different loading ratios were prepared for characterization. Then, the PPNPS were evaluated for in vitro controlled release of phlorotannin, toxicity and antioxidant activities at the ratio of phlorotannin to PVP 1:8. The results indicated that the PPNPS showed a slow and sustained kinetic release of phlorotannin in simulated gastrointestinal fluids, they were non-toxic to HaCaT keratinocytes and they could reduce the generation of endogenous reactive oxygen species (ROS). Therefore, PPNPS have the potential to be a useful platform for the utilization of phlorotannin in both pharmaceutical and cosmetics industries.

Accelerated accumulation of retinal α-synuclein (pSer129) and tau, neuroinflammation, and autophagic dysregulation in a seeded mouse model of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by accumulation of misfolded α-synuclein within the central nervous system (CNS). Visual problems in PD patients are common, although retinal pathology associated with PD is not well understood. The purpose of this study was to investigate retinal pathology in a transgenic mouse model (TgM83) expressing the human A53T α-synuclein mutation and assess the effect of α-synuclein "seeding" on the development of retinal pathology. Two-month-old TgM83 mice were intracerebrally inoculated with brain homogenate from old (12-18 months) TgM83 mice. Retinas were then analyzed at 5 months of age. We analyzed retinas from 5-month-old and 8-month-old uninoculated healthy TgM83 mice, and old (12-18 months) mice that were euthanized following the development of clinical signs. Retinas of B6C3H mice (genetic background of the TgM83 mouse) served as control. We used immunohistochemistry and western blot analysis to detect accumulation of α-synuclein, pTauThr231, inflammation, changes in macroautophagy, and cell death. Raman spectroscopy was used to test the potential to differentiate between retinal tissues of healthy mice and diseased mice. This work demonstrates retinal changes associated with the A53T mutation. Retinas of non-inoculated TgM83 mice had accumulation of α-synuclein, "pre-tangle" tau, activation of retinal glial cells, and photoreceptor cell loss by 8 months of age. The development of these changes is accelerated by inoculation with brain homogenate from clinically ill TgM83 mice. Compared to non-inoculated 5-month-old TgM83 mice, retinas of inoculated 5-month-old mice had increased accumulation of α-synuclein (pSer129) and pTauThr231 proteins, upregulated microglial activation, and dysregulated macroautophagy. Raman spectroscopic analysis was able to discriminate between healthy and diseased mice. This study describes retinal pathology resulting from the A53T mutation. We show that seeding with brain homogenates from old TgM83 mice accelerates retinal pathology. We demonstrate that Raman spectroscopy can be used to accurately identify a diseased retina based on its biochemical profile, and that α-synuclein accumulation may contribute to accumulation of pTauThr231 proteins, neuroinflammation, metabolic dysregulation, and photoreceptor cell death. Our work provides insight into retinal changes associated with Parkinson's disease, and may contribute to a better understanding of visual symptoms experienced by patients.

Zinc-Chelating Mechanism of Sea Cucumber (Stichopus japonicus)-Derived Synthetic Peptides.

In this study, three synthetic zinc-chelating peptides (ZCPs) derived from sea cucumber hydrolysates with limited or none of the common metal-chelating amino-acid residues were analyzed by flame atomic absorption spectroscopy, circular dichroism spectroscopy, size exclusion chromatography, zeta-potential, Fourier transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy. The amount of zinc bound to the ZCPs reached maximum values with ZCP:zinc at 1:1, and it was not further increased by additional zinc presence. The secondary structures of ZCPs were slightly altered, whereas no formation of multimers was observed. Furthermore, zinc increased the zeta-potential value by neutralizing the negatively charged residues. Only free carboxyl in C-terminus of ZCPs was identified as the primary binding site of zinc. These results provide the theoretical foundation to understand the mechanism of zinc chelation by peptides.

Phlorotannins from Undaria pinnatifida Sporophyll: Extraction, Antioxidant, and Anti-Inflammatory Activities.

Undaria pinnatifida sporophyll (U. pinnatifida) is a major byproduct of U. pinnatifida (a brown algae) processing. Its phenolic constituents, phlorotannins, are of special interest due to their intrinsic ability to precipitate proteins. Herein, a high-temperature extraction procedure was used to isolate these biologically active compounds. The heating temperature, heating time, and extraction solvent (ethanol) concentration were examined with response surface analysis to determine the optimal conditions to achieve the maximum extraction rate. The analysis revealed the optimal conditions to be: 170 °C of heating temperature, 5.2 h of heating time, and 52% ethanol concentration for a yield of 10.7 ± 0.2 mg gallic acid equivalent/g dry weight (GAE/g DW) of sample. Compared to epigallocatechin gallate (EGCG), the extracted phlorotannins displayed higher antioxidant activity on H2O2-induced RAW 264.7 cells with improved efficiency. Furthermore, the compounds exhibited strong anti-inflammatory activity. These findings potentially can be utilized to guide development of novel functional foods and food supplements from sea-originated resources such as brown algae.

Isolation and identification of zinc-chelating peptides from sea cucumber (Stichopus japonicus) protein hydrolysate.

BACKGROUND: Zinc is known to play an essential role in the biological activities in the human body. In this study, a zinc-chelating peptide (ZCP) produced by Alcalase-assisted hydrolysis of the body wall of sea cucumber was isolated and identified. The ZCP was purified stepwise by ultrafiltration, anion-exchange chromatography, and gel filtration chromatography, in conjunction with ultraviolet-visual (UV-visual) spectrophotometry, which was used to analyze each purified fraction. RESULTS: Analysis of the purified ZCP revealed that its zinc-chelating ability was 33.31%. Analysis of isothermal titration calorimetry suggested that the binding of ZCP and zinc (N ≈ 2) was endothermic, with weak binding affinity. Fourier transform infrared spectroscopy spectra (FTIR) indicated that carboxylic and amide groups in ZCP were the primary binding sites of Zn. Sequencing the result by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) showed that a representative ZCP had the sequence WLTPTYPE with a molecular weight of 1005.5 Da. CONCLUSION: These results provide a promising foundation for the production of zinc supplements from sea-cucumber-derived ZCPs. © 2019 Society of Chemical Industry.

Omics-prediction of bioactive peptides from the edible cyanobacterium Arthrospira platensis proteome.

BACKGROUND: Bioinformatics approaches are widely used to evaluate the prospects of novel protein sources in bioactive peptide research. Edible cyanobacteria are considered as potential protein precursors. However, the abundance of unicellular cyanobacterial proteins is largely unknown and highly dynamic according to the cultivation conditions, which need to be considered in this research field. The objective of this work was to evaluate the protein abundance of Arthrospira platensis, as well as to map the bioactive peptide sequences from the high-abundance proteins of the A. platensis proteome. RESULTS: The high-abundance proteins of the A. platensis proteome were identified with a high-performance liquid chromatography-tandem mass spectrometry-based method. A total of 593 proteins were detected and quantified. The occurrence frequency of the bioactive peptides in A. platensis proteome was calculated according to the amino acid sequences via the bioinformatics approaches. Further in silico digested by trypsin, pepsin and chymotrypsin, these proteins liberated 78, 99, and 96 bioactive peptides, respectively. In each case, angiotensin-converting enzyme inhibitors and dipeptidyl peptidase IV inhibitors were enriched. CONCLUSION: This work will help rationally design the protocols for cyanobacterial cultivation, protein pre-treatment and peptide separation, and further produce more peptides with specific functions. © 2017 Society of Chemical Industry.

Analytical characterization using surface-enhanced Raman scattering (SERS) and microfluidic sampling.

With the rapid development of analytical techniques, it has become much easier to detect chemical and biological analytes, even at very low detection limits. In recent years, techniques based on vibrational spectroscopy, such as surface enhanced Raman spectroscopy (SERS), have been developed for non-destructive detection of pathogenic microorganisms. SERS is a highly sensitive analytical tool that can be used to characterize chemical and biological analytes interacting with SERS-active substrates. However, it has always been a challenge to obtain consistent and reproducible SERS spectroscopic results at complicated experimental conditions. Microfluidics, a tool for highly precise manipulation of small volume liquid samples, can be used to overcome the major drawbacks of SERS-based techniques. High reproducibility of SERS measurement could be obtained in continuous flow generated inside microfluidic devices. This article provides a thorough review of the principles, concepts and methods of SERS-microfluidic platforms, and the applications of such platforms in trace analysis of chemical and biological analytes.

[Design of Rehabilitation Training System with Electromyography Feedback for Stroke Patients].

This paper proposed a rehabilitation training system with electromyography (sEMG) feedback for stroke patients based on ARM embedded system and LabVIEW. The system can achieve real-time acquisition, processing and dualview of multi-channel sEMGs and compute related sEMG parameters including iEMG, RMS, MPF and co-contraction ratio. The system was detected by clinical experiments and related inspection department. The result showed that the system is functional, interactive and in accordance with the relevant standards for medical devices so that it can fully satisfy the clinical demands. In addition, the system can help doctors to master the training state of the patient more effectively in a real-time and quantitative way that is direct to improve the training programs of stroke patients.

Improvement of Surimi Gel from Frozen-Stored Silver Carp.

Silver Carp (SC) is an under-utilized, invasive species in North American river systems. In this study, the synergistic effects of manufactured Microfiber (MMF), Transglutaminase (TG), and chicken skin collagen (CLG)) to enhance surimi gel quality from frozen SC were studied. The gel strength, textural properties, rheological properties, water-holding capacity (WHC), water mobility, microstructure, and protein composition of the gel samples were determined to assess the impact of the additives individually and synergistically. The results suggested that TG had the most pronounced effect on the surimi gel properties by promoting protein cross-linking. Synergistic effects between TG, MMF, and CLG can bring effective gel property enhancement larger than the individual effect of each additive alone. With the established response-surface models, the combination of CLG and MMF can be optimized to produce surimi gels with less TG but comparable in properties to that of the optimal result with high TG usage. The findings of this study provided a technical foundation for making high-quality surimi gel products out of frozen-stored SC with synergistic utilization of additives, which could serve as guidelines for the industrial development of new surimi products.

Re-examining the governance effect of China's environmental protection tax.

China has long exercised environmental control through the imposition of sewage charges. The start of the environmental protection tax on January 1, 2018, means that China has entered a new phase of environmental control. Unlike many previous studies on the role of environmental taxes at the firm level, this paper examines whether environmental taxes affect pollution emissions by influencing the behavioral choices of micro-actors. This paper first reviews the Pyrrhic tax, the Porter hypothesis, and the "double dividend effect." We then construct provincial panel data for 30 provinces in China from 2012 to 2019 as a sample, use the environmental protection tax as a natural experiment to evaluate the policy of this environmental protection tax using propensity score matching and difference-in-differences model, investigate the intermediate transmission mechanism of the policy implementation, and then analyze the differences in policy effects between provinces with different levels of economic development. The increased tax burden in 2018 led to a general reduction in provincial pollution emissions in which technological innovation by various groups, including firms and universities, had a mediating role.

Bacterial community succession in aerobic-anaerobic-coupled and aerobic composting with mown hay affected C and N losses.

The primary objective of this work was to investigate how the dominant microbial species change and affect C and N losses under aerobic and aerobic-anaerobic-coupled composting of mown hay (MH, ryegrass) and corn stover (CS) mix. Results showed that C and N losses in aerobic compost of MH-CS were significantly decreased by 19.57-31.47% and 29.04-41.18%, respectively. 16S rRNA gene sequencing indicated that the bacterial microbiota showed significant differences in aerobic and aerobic-anaerobic-coupled composting. LEfSe analyses showed that aerobic composting promoted the growth of bacteria related to lignocellulosic degradation and nitrogen fixation, while aerobic-anaerobic-coupled composting promoted the growth of bacteria related to denitrification. Correlation analysis between bacterial community and environmental factors indicated that moisture content (MC) was the most important environmental factor influencing the differentiation of bacterial growth. KEGG analysis showed that aerobic composting enhanced the amino acid, carbohydrate, and other advantageous metabolic functions compared to that of aerobic-anaerobic-coupled composting. As a conclusion, the addition of 10-20% corn stover (w/w) to new-mown hay (ryegrass) appeared to inhibit anaerobic composting and prompt aerobic composting in MH-CS mix, which led to the effective utilization of mown hay as a resource for composting.

Continuous cropping of potato changed the metabolic pathway of root exudates to drive rhizosphere microflora.

For potato production, continuous cropping (CC) could lead to autotoxicity buildup and microflora imbalance in the field soil, which may result in failure of crops and reduction in yield. In this study, non-targeted metabolomics (via liquid chromatography with tandem mass spectrometry (LC-MS/MS)) combined with metagenomic profiling (via high-throughput amplicon sequencing) were used to evaluate correlations between metabolomics of potato root exudates and communities of bacteria and fungi around potato plants to illustrate the impacts of CC. Potato plants were grown in soil collected from fields with various CC years (0, 1, 4, and 7 years). Metabolomic analysis showed that the contents and types of potential autotoxins in potato root exudates increased significantly in CC4 and CC7 plants (i.e., grown in soils with 4 and 7 years of CC). The differentially expressed metabolites were mainly produced via alpha-linolenic acid metabolism in plant groups CC0 and CC1 (i.e., no CC or 1 year CC). The metabolomics of the groups CC4 and CC7 became dominated by styrene degradation, biosynthesis of siderophore group non-ribosomal peptides, phenylpropanoid biosynthesis, and biosynthesis of various plant secondary metabolites. Continuous cropping beyond 4 years significantly changed the bacterial and fungal communities in the soil around the potato crops, with significant reduction of beneficial bacteria and accumulation of harmful fungi. Correlations between DEMs and microflora biomarkers were established with strong significances. These results suggested that continuous cropping of potato crops changed their metabolism as reflected in the plant root exudates and drove rhizosphere microflora to directions less favorable to plant growth, and it needs to be well managed to assure potato yield.

Transmission and retention of antibiotic resistance genes (ARGs) in chicken and sheep manure composting.

Transmission of ARGs during composting with different feedstocks (i.e., sheep manure (SM), chicken manure (CM) and mixed manure (MM, SM:CM = 3:1 ratio) was studied by metagenomic sequencing. 53 subtypes of ARGs for 22 types of antibiotics were identified as commonly present in these compost mixes; among them, CM had higher abundance of ARGs, 1.69 times than that in SM, while the whole elimination rate of CM, MM and SM were 55.2%, 54.7% and 42.9%, respectively. More than 50 subtypes of ARGs (with 8.6%, 11.4% and 20.9% abundance in the initial stage in CM, MM and SM composting) were "diehard" ARGs, and their abundance grew significantly to 56.5%, 63.2% and 69.9% at the mature stage. These "diehard" ARGs were transferred from initial hosts of pathogenic and/or probiotic bacteria to final hosts of thermophilic bacteria, by horizontal gene transfer (HGT) via mobile gene elements (MGEs), and became rooted in composting products.