Search Results (72)

Antimicrobial resistance (AMR) is a major global health problem, exacerbated by the excessive and inappropriate use of antibiotics in human medicine, animal care and agriculture. Therefore, new strategies and compounds are needed to overcome this issue. In this view, it may be appropriate to reconsider existing biomaterials to alleviate antibiotic overuse. Chitin, a naturally abundant amino mucopolysaccharide, is a poly-β-1, 4-N-acetylglucosamine (GlcNAc). It is a white, hard, inelastic, nitrogenous polysaccharide and the major source of surface pollution in coastal areas. Chitosan derives from the partial N-deacetylation of chitin and originates from the shells of crustaceans and the fungi cell walls. It is a nontoxic natural antimicrobial polymer approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitin and chitosan, as non-toxic biopolymers, are useful compounds for wastewater treatment to remove pollutants, such as pharmaceuticals, heavy metals and dyes. The described features make these biopolymers intriguing compounds to be investigated for their application as antibacterials. Full article

Ocean acidification (OA) associated with climate change is expected to lower the ocean’s pH by 0.5 units by 2100. Whilst associated effects such as coral bleaching and shell calcification are well documented, lesser-known impacts are the ‘invisible’ effects on animal sensory systems. Olfactory disruption impacts the behaviour towards chemical cues in many marine species, including crustaceans. We examine the effects of microplastic odour and additional stressors on the European green crab C. maenas. Using uridine diphosphate (UDP) and uridine triphosphate (UTP) as a sex pheromone bouquet, glutathione (GSH) as a food cue, and polyethylene (PE) as plastic odour, cues were mixed with carboxycellulose to create slow-release gels. Crabs were exposed to gels in seawater pH values of 8.2, 7.6, and 7.2. Crabs took longer to react to all odours in reduced pH conditions (pH 8.2 to pH 7.2, p = 0.0017). At a low pH, PE-exposed crabs exhibited attraction towards microplastic odour and changed behavioural responses by burying. The study confirms low pH as disruptive to olfaction and highlights that plastic derivatives can become more bioactive at reduced pH levels, potentially increasing the threat posed by microplastic pollution. Further research is required to determine the potential long-term impacts of the combined threat of microplastics and reduced pH in the environment. Full article

Semicarbazide (SEM), a metabolite of nitrofurazone (NFZ), is widely used to detect the illegal application of NFZ in crustaceans. The conventional detection method involves chemical derivatization combined with reversed-phase liquid chromatography–tandem mass spectrometry (RPLC-MS/MS), which is both complex and time-consuming. To address this limitation, a more efficient approach was developed for SEM detection. This study introduces a modified QuEChERS pretreatment method coupled with hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS) for detecting SEM in crustaceans. The proposed method is simple, fast, and highly accurate, making it universally applicable for SEM detection in crustaceans. Additionally, the method was applied to investigate NFZ metabolism in Macrobrachium rosenbergii with a kinetic model. The findings suggested a plausible mechanism for the absorption of NFZ and its subsequent transfer from meat to the shell. In conclusion, this study provides a simple and rapid technique for SEM detection in crustaceans with immense application value. Full article

The red king crab, Paralithodes camtscaticus, is a commercially significant crustacean that supports lucrative fisheries in Russia, the USA, and Norway. The western Kamchatka shelf, located in the Sea of Okhotsk, is home to one of the most important populations of the red king crab. In this study, we have conducted a review of the symbionts associated with P. camtscaticus in the waters off the Kamchatka Peninsula. A total of 42 symbiotic species belonging to 14 different phyla were identified in association with the red king crab. Out of these, 14 species were found to be parasitic to the red king crab, while the remaining 28 were either commensal or epibiont in nature. The taxa with the highest number of associated species included ciliates (11), crustaceans (8), and acanthocephalans (4). Our study found that red king crabs suffering from shell disease exhibited a more diverse symbiotic fauna and higher infestation indices as compared to healthy crabs, which were found to be free from parasites. Dangerous symbionts, such as dinoflagellates Hematodinium sp. and rhizocephalan barnacles Briarosaccus callosus, had low incidence rates, indicating that the red king crab population in the Sea of Okhotsk is in good condition with respect to population abundance, health, and recruitment and is not being adversely impacted by symbiotic organisms. Full article

This study presents the first comprehensive data on a vermetid formation along the Apulian coast of the Adriatic Sea, representing one of the northernmost records in the Mediterranean. Surveys along the Brindisi coastline employed visual inspection to map the bioconstruction’s distribution and extension. Detailed data on the bioconstruction inner and the outer edge length, thickness, width, slope and topographic complexity were collected at three selected sites. Moreover, photographic replicates were used to assess shell aperture density and diameters of Dendropoma sp. Associated fauna was studied using two quantitative sampling squares in each transect. The results showed that the vermetid bioconstruction consisted of a thin, encrusted monolayer (thickness < 1.5 cm) that extended for 3.273 linear kilometers, covering 17.23% of the investigated area; it had an average width of 0.5 m, with a mean density of Dendropoma sp. at 2.52 ind/cm². The associated fauna was composed of 47 taxa dominated by crustaceans, mollusks and annelids. Species richness was correlated with the bioconstruction’s thickness and complexity. These findings underline the ecological importance of vermetid bioconstructions as biodiversity hotspots. The lack of massive mortality events along the Apulian coast, in contrast to other Mediterranean vermetid bioconstructions, underscores the necessity for targeted conservation measures. Full article

Eriocheir sinensis is an important and popular crustacean species in China, producing huge economic benefits. Large individuals of E. sinensis are preferred due to market demand. The long-term goal of our research group is to produce a new variety of E. sinensis with better growth performance and stronger abilities to resist environmental changes through mass selection. The present study aimed to evaluate the progress of the genetic breeding of E. sinensis by analyzing the genetic diversity and genetic distance between the basic breeding population (pooled population of Suqian and Yixing, G0) and generation 1 (G1) using whole-genome sequencing (WGS). The growth traits, including body weight, shell length, shell width, and third appendage length, in the G1 generation increased by 8.3%, 7.9%, 9.6%, and 9.3%, respectively, compared with those of the G0 generation, indicating that the G1 generation showed better growth performance. A total of 372,448,393 high-quality single nucleotide polymorphisms (SNPs) were detected in 40 E. sinensis individuals, with an average of 9,331,209.83 SNPs. The fixation index values were 0.007 between the Yixing and Suqian populations and 0.015 between the G0 generation and G1 generation, indicating a close genetic background between these groups, especially when considered in combination with the phylogenetic tree and principal component analysis. All of these data suggest that genetic information was stably inherited by the G1 generation, with no introduction of foreign genetic information during the genetic breeding process. In addition, the genetic diversity analysis revealed that the G0 and G1 generations showed a high level of genetic diversity and a relatively stable genetic structure. The present study evaluated the recent progress of the genetic improvement of E. sinensis by our research group, providing valuable evidence for further genetic improvement in this species. Future studies will be performed to select growth-related SNPs and genes through genome-wide association studies. Full article

Soil pollution by heavy metals (HMs) is a major environmental problem around the world. The addition of biowaste-based stabilizers for HM remediation has recently gained attention due to its relatively low cost and eco-risk, abundance, ease of operation, and quick remediation results. Among these stabilizers, shell (crustacean shell, bivalve shell, and eggshell), starfish, and bone-based stabilizers are particularly attractive because of their high Ca and P contents, allowing for highly efficient HM immobilization and simultaneous supplement of nutrients to the soil. However, a comprehensive review focusing on these stabilizers is currently missing. Therefore, this review attempts to summarize the HM immobilization efficiency of these stabilizers and the mechanisms associated with HM stabilization, and perform an operation cost estimation and cost comparison. Cost comparisons among different stabilizers are widely ignored in reviews due to the lack of reliable cost estimation tools or methods. However, for practical application in soil remediation, cost is one of the most important factors to consider. Thus, a simple but reasonable cost estimation method is developed and discussed in this review. Bivalve shell-based stabilizers demonstrated the most promising results for the immobilization of soil HMs in terms of higher performance and lower cost. Current research limitations, challenges, and recommendations regarding possible future research directions are also provided. Full article

Chitin, the second most abundant biopolymer after cellulose, is an important resource for biosourced materials. The global demand for chitin is rapidly increasing, however, the majority of industrial chitin is sourced from crustacean shells, which may be less accessible in regions without seafood waste. Therefore, it is crucial to explore alternative chitin sources, such as those derived from beetles and other arthropods. This study investigated chitin extraction from nine species of Curculionidae (true weevils), which are recognized as crop pests. The extraction process and yields were described, and the isolated chitin was characterized by SEM, IR spectroscopy, elemental analysis, XRD, and ash and water content measurements. This work highlights the potential of Curculionidae as an alternative chitin source. Full article

Nitrite is a common pollutant in marine environments and can cause mortality in crustaceans and bivalves. The purpose of the current study is to understand nitrate’s toxicity to juvenile clams due to its potential impact on aquaculture and marine ecosystems. Juvenile sunray surf clams (Mactra chinensis Philippi) (1.00 ± 0.10 cm shell length, 0.75 ± 0.04 cm shell height) were exposed to varying concentrations of nitrite for 96 h and 20 days, respectively. The LC₅₀ for survival at 96 h was 37 mg/L NO₂-N. Histological evaluations were made on juvenile clams exposed at 30 mg/L after 20 d of exposure. Epithelial cells and digestive diverticulum are the best sub-lethal effect indicators. Shell length and antioxidant enzyme activities were measured at the beginning of the experiment and then observed 10 and 20 days after exposure. A logarithmic relationship was obtained between the relative growth rate (based on the shell length) of juvenile M. chinensis and the nitrite concentration. Compared to the control, activity suppression of superoxide dismutase and catalase activity was detected from the concentration of 1 mg/L NO₂-N. It is recommended that nitrite concentrations remain below 1 mg/L to prevent stress during the early developmental stages of clams. Full article

Chitin (Ct) is a crucial biopolymer present in fungi, algae, arthropods, and is usually obtained from crustacean shells. Chitosan (Cs) is a derivative from Ct deacetylation, and possesses numerous uses in various agro-industrial fields. Research on fungal-derived Ct and Cs is mostly focused on pharmaceutical uses, however their uses for plant disease control remain less explored. The main objective of the current study is to evaluate the possibility of using chitosan obtained from mushroom Pleurotus eryngii (Cs-Pe) for controlling some phytopathogens compared to commercial chitosan (C.Cs). This study is focused on the following key areas: (i) extracting Ct from P. eryngii mycelium and converting it to Cs through deacetylation, using both bleaching and non-bleaching methods; (ii) conducting a physico-chemical characterization and in vitro evaluation of the antimicrobial activity of the obtained Cs; (iii) performing an in vivo assessment of the phytotoxic and cytotoxic effects of Cs; and (iv) investigating in vivo the impact of the studied chitosan on fruit quality and its biocontrol efficacy against Monilinia laxa infections in plum fruits. Results showed that Cs-Pe, especially the unbleached one, displayed promising in vitro antimicrobial activity against the majority of tested pathogens. Regarding the cytotoxicity, the highest significant increase in cell abnormality percentage was observed in the case of C.Cs compared to Cs-Pe. In the in vivo study, Cs-Pe acted as a protective barrier, lowering and/or preventing moisture loss and firmness of treated plums. The studied Cs-Pe demonstrated notable efficacy against M. laxa which decreased the fruits’ percentage decline. These results strongly suggest that Cs derived from P. eryngii is a potential candidate for increasing plums’ shelf-life. This research shed light on the promising applications of P. eryngii-derived Cs in the agri-food field. Full article

Balanomorph (acorn) barnacles are found throughout the world’s coastal oceans, and their success is dependent on a hard, mineralized, outer shell. Although macro-scale morphology of barnacle shells has been studied extensively, relatively little is known about shell properties at the micron-scale and if such properties vary among species. We assessed shell structure, mechanics, and composition in seven species of balanomorph barnacles from five genera. Three species, Amphibalanus amphitrite, Amphibalanus improvisus, and Austrominius modestus, were laboratory-reared, enabling direct comparison of shell properties of barnacles grown under the same conditions for the same duration. Four other species, Semibalanus balanoides, Amphibalanus eburneus, Chthamalus stellatus, and Tetraclita rubescens, were field-collected. At the macro- and meso-scales, shell properties varied markedly among species, with differences in the number of shell plates, the presence of canals within the plates, mineralization of the base, and shell plate thickness. At the micron-scale, however, structure was remarkably similar among species. Plates of all species were constructed of irregular micron-scale crystallites, with a broad range of crystallite dimensions observed within the same shell. Similarly, micromechanical properties did not vary among species, regardless of testing orientation. Calcium carbonate was identified as calcite in all species assessed with no other mineral phases present, and calcium content did not vary among species. Hence, despite variation in the overall macro- and meso-scale morphology of barnacles, all appear to be built using the same, evolutionarily conserved, mineralization pathway. Full article

Crustacean shells, waste from the seafood industry, have been identified as a potential sustainable material for the adsorption of lead, a potent heavy metal found in the discharge of industrial processes. The dynamics and kinetics of its performance were evaluated in batch experiments under pH, temperature, time, and initial concentration. A unique and non-intuitive key finding was that among the native components of the crab shell matrix, i.e., chitin, protein, and calcium carbonate, calcium carbonate was instrumental in sequestration. The role of protein was minimal, whereas the efficiency of chitin in lead complexation was linked to the lead atomic radius, which, of the crab shell components, we determined was very prone to interacting with chitin. Full article

Chitin and chitosan, abundant biopolymers derived from the shells of crustaceans and the cell walls of fungi, have garnered considerable attention in pharmaceutical circles due to their biocompatibility, biodegradability, and versatile properties. Deep eutectic solvents (DESs), emerging green solvents composed of eutectic mixtures of hydrogen bond acceptors and donors, offer promising avenues for enhancing the solubility and functionality of chitin and chitosan in pharmaceutical formulations. This review delves into the potential of utilizing DESs as solvents for chitin and chitosan, highlighting their efficiency in dissolving these polymers, which facilitates the production of novel drug delivery systems, wound dressings, tissue engineering scaffolds, and antimicrobial agents. The distinctive physicochemical properties of DESs, including low toxicity, low volatility, and adaptable solvation power, enable the customization of chitin and chitosan-based materials to meet specific pharmaceutical requirements. Moreover, the environmentally friendly nature of DESs aligns with the growing demand for sustainable and eco-friendly processes in pharmaceutical manufacturing. This revision underscores recent advances illustrating the promising role of DESs in evolving the pharmaceutical applications of chitin and chitosan, laying the groundwork for the development of innovative drug delivery systems and biomedical materials with enhanced efficacy and safety profiles. Full article

Waste biogenic materials derived from seafood exploitation represent valuable resources of new compounds within the blue bioeconomy concept. Here, we describe the effectiveness of Raman technology implementation as an in-line tool for the demineralization process control of crustaceans or gastropods. Transparent chitin polymeric foils and calcium acetate by-products were obtained from three waste crustacean shells (C. sapidus, S. mantis, and M. squinado) using a slow, green chemical approach employing acetic acid. Progressive mineral dissolution and increasing of the Raman characteristic signal of chitin is shown in a time-dependent manner using NIR-Raman spectroscopy, while resonance Raman shows intact carotenoids in reacted shells after 2 weeks. Chitin foil products are species-specific, and the demineralization bath of the waste shell mixture can be effectively tracked by Raman tools for solvent control and decision making for the recovery of calcium acetate by-products. Comparatively obtained calcium acetate from Rapana venosa snail shells, the subject of Raman analyses, allowed assessing by-product identity, hydration status, purity, and suitability as recrystallized material for further use as a pharmaceutical compound derived from different crustaceans or gastropod species. Cross validation of the results was done using FT-IR, XRD, and SEM-EDX techniques. A hand-held flexible TacticID Raman system with 1064 nm excitation demonstrated its effectiveness as a rapid, in-line decision making tool during process control and revealed excellent reproducibility of the lab-based instrument signal, suitable for in situ evaluation of the demineralization status and solvent saturation control. Full article

The coconut crab, Birgus latro, has black protrusions on the tops of its walking legs and claw fingers. In addition, there are regularly aligned small black protrusions on parts of the exoskeleton surface of the claws and leg. In this study, the elemental composition, crystal structure, tissue structure, and mechanical properties of these protrusions were studied using a materials science approach, and the results were compared with those of mineralized cuticle. These leg tips were found to be a non-calcified fibrous tissue of α-chitin connected to the mineralized cuticle. The tip of the second walking leg was elongated and had a pointed shape with an oval cavity at its center that was more than 1000 times larger than the pore tubes (100–350 nm) of the mineralized cuticle. It was very soft, with a hardness of 0.4 GPa, corresponding to 11–12% of the hardness of the hard exocuticle and 55–57% of the hardness of the soft endocuticle. The elastic modulus of 8.0 GPa obtained by means of nanoindentation testing was consistent with that of α-chitin fibers of shrimp shells obtained by means of tensile testing. These soft protrusions provide a secure grip on the surfaces of trees or rocks and protect the claw fingertips. It was concluded that the black protrusions are related to a unique ecological (engaging in vertical movements, entering and exiting limestone caves, and escape behavior) aspect of the coconut crab, the largest terrestrial crustacean. Full article