A comprehensive review on hemocyanin from marine products: Structure, functions, its implications for the food industry and beyond

The new insight into the impact of hemocyanin on quality deterioration of Pacific white shrimp during refrigerated storage

This study explored the role of hemocyanin (Hc) in shrimp quality deterioration during storage. Pacific white shrimp (Litopenaeus vannamei) subjected to bloodletting and stored at 4 °C showed 22.97 % and 21.51 % reduction in peroxide value and thiobarbituric acid reactive substance (TBARS) at 3 d, respectively, compared to the control. Furthermore, key quality indicators, including K-value, water holding capacity, color, and total volatile basic nitrogen improved significantly. In washed shrimp model with exogenously added Hc and Cu2+, the effect of Hc group on promoting lipid oxidation was stronger than Cu2+ group, and TBARS level increased by 16.42 %. Cu2+ released from Hc activated adenosine monophosphate deaminase and accelerated inosine monophosphate degradation into hypoxanthine riboside and hypoxanthine, resulting in freshness loss. Hc also activated polyphenol oxidase, leading to shrimp blackening. This is the first study to reveal the impact of Hc and Cu2+ on the quality deterioration of Pacific white shrimp during storage.

Biophysical Characterization of Shrimp Hemocyanins: Stability and Emerging Biotechnological Applications

Hemocyanins are oxygen-transporting proteins found in crustaceans and other arthropods, playing key roles in immune defense and metabolic regulation. Due to their stability and bioactive properties, Hcs have gained increasing interest in biotechnological and biomedical applications. However, detailed biophysical characterization is crucial to understanding their functional potential. In this study, the hemocyanin was extracted and purified from Macrobrachium acanthurus (HcMac) using ultracentrifugation and size-exclusion chromatography. The molecular mass of HcMac was determined by SDS-PAGE electrophoresis, MALDI-TOF mass spectrometry, and analytical ultracentrifugation. Spectroscopic analyses, including UV-Vis absorption, fluorescence emission, and light scattering intensity, were used to assess the structural stability of the compound under various pH conditions. HcMac was identified as a hexameric protein (~450 kDa) composed of monomeric subunits of 75 and 76 kDa. The protein maintained its oligomeric stability and oxygen-binding affinity in the pH range of 5.0-7.4. However, extreme pH conditions (below 4.4 and above 7.5) induced structural alterations, leading to dissociation and conformational changes, as evidenced by fluorescence emission and UV-Vis spectra. The isoelectric point was determined to be between pH 4.3 and 5.3, consistent with other crustacean HCs. These findings reinforce the structural robustness of HcMac and suggest its potential for biotechnological applications. The high stability of HcMac under physiological pH conditions indicates its suitability for biomedical research, including immunomodulatory and antimicrobial applications. Future studies integrating bioinformatics, proteomics, and immunological assays will be essential to explore the therapeutic potential of HcMac.

Pomacea canaliculata hemocyanin as a novel natural immunostimulant in mammals

Introduction

Gastropod hemocyanins are potent immunostimulants in mammals, a trait associated with their large molecular size and unusual glycosylation patterns. While the hemocyanin from the marine snail keyhole limpet (KLH), has been widely studied and successfully employed as a carrier/adjuvant in several immunological applications, as well as a non-specific immunostimulant for bladder cancer treatment, few other gastropod hemocyanins have been biochemically and immunologically characterized. In this work, we investigated the immunogenic properties of the hemocyanin from Pomacea canaliculata (PcH), an invasive south American freshwater snail. This species, known for its high reproductive rate and easy rearing, represents a promising source of potential biomedical compounds, including hemocyanin.

Methods

Employing flow cytometry, fluorescence microscopy, immunoassays, and quantitative PCR, we analysed the effects of PcH on THP-1 monocytes and their derived macrophages, as well as its ability to induce humoral response on C57BL/6 mice. Additionally, we evaluated the structural stability of PcH across a wide range of temperature and pH values.

Results and discussion

Our findings demonstrate that PcH is a structurally stable protein that not only triggers a pro-inflammatory effect on THP-1 derived-macrophages by increasing IL1-β and TNF-α levels, but also promotes phenotypic changes associated with the monocyte-to-macrophage differentiation. Moreover, the humoral response induced by PcH in mice was indistinguishable from that of KLH, highlighting the promising immunostimulatory properties of this freshwater snail hemocyanin.

Research progress and immunological insights of shrimp allergens

Allergic diseases have become a major health issue in the 21st century. The FAO has pinpointed the eight most prevalent allergens worldwide, with shrimp allergy attracting global concern due to its escalating incidence. This review delves into the current knowledge of shrimp allergen types and traits, immune response mechanisms, advancements in cross-reactivity research, and breakthroughs in diagnostic and therapeutic methods. It highlights the variety of shrimp allergens, such as tropomyosin and arginine kinase, and concentrates on IgE-mediated immediate hypersensitivity reactions, involving mast cells and basophils, alongside the role of T cells and cytokines in non-IgE-mediated delayed hypersensitivity reactions. The exploration of cross-reactivity underscores the connection between shrimp allergy and allergies to other animals. Utilizing bioinformatics tools, including homology analysis, epitope prediction, and molecular modeling, has enhanced our comprehension of allergen molecular features. In treatment and diagnosis, innovative approaches like immunotherapy and gene editing technology hold potential to decrease allergic sensitivity, while emerging reduction techniques like heat treatment and enzymatic hydrolysis offer new strategies for the prevention and management of food allergies. The evolution of allergen detection and purification technologies has spurred innovation in testing methodologies, encompassing traditional in vivo tests like SPT and DBPCFC, in addition to a range of other techniques such as immunoassays, biochip technology, PCR, and histamine release experiments, propelling the instantaneous and accurate identification of allergens. These scientific breakthroughs not only expand our understanding of shrimp allergen biology but also lay the foundation for developing more effective allergy prevention and control strategies.

Improper toy waste handling can harm human health via seafood consumption: A comprehensive health risk assessment of heavy metals

Toy production has been increasing over the last few decades to meet the growing demands for toys across the globe, which has inevitably worsened the problem of toy waste. Given the lack of modern waste disposal facilities, rural villagers in many developing countries often discard and incinerate toy waste in backyards or riverbanks, which may release the pollutants from toys (e.g., heavy metals), contaminate the surrounding areas, and eventually threaten the health of residents. As such, this study examined the impact of improper toy waste handling on the nearby aquaculture site by measuring the contamination level of heavy metals (As, Cd, Cu, Pb, and Zn) in the sediment and seafood (crabs, shrimps, and fish). The health risk of heavy metals via seafood consumption was assessed in different groups of people (males, females, teenagers, and seniors). Results showed that the sediment and seafood at the aquaculture site were generally not contaminated with heavy metals (contamination factor and bioaccumulation factor <1). However, consuming the seafood cultured at this site, especially for crabs, could pose a health risk to humans due to As and Cd (hazard quotient > 1), irrespective of their age and gender. This risk could not be lowered by cooking, except As by boiling. Overall, we revealed that improper toy waste handling did not cause severe heavy metal pollution in the surrounding environment, but the consumption of contaminated seafood could still threaten human health. To safeguard public health, we propose that toy waste should be appropriately treated by the authorities concerned. In addition, consuming seafood with long culture periods (e.g., crabs) should be reduced to minimize the dietary intake of heavy metals and their associated health risk.