Thermal accelerated urease-driven hyaluronan-targeted melanin nano-missile for bio-radar detection and chemodrug-free phototherapy.

Polymer-based nanomotors are attracting increasing interest in the biomedical field due to their microscopic size and kinematic properties which support overcoming biological barriers, completing cellular uptake and targeted blasting in limited spaces. However, their applications are limited by the complex viscous physiological environment and lack of sufficient biocompatibility. This manuscript firstly reports a natural melanin nano-missile of MNP@HA-EDA@Urease@AIE PS (MHUA) based on photothermally accelerated urease-driven to achieve chemodrug-free phototherapy. Compared to conventional nano-missiles that only provide driving force, this photothermally accelerated urease-driven nanomotor is independent of chemodrug to maximise biocompatibility, and achieve ideal therapeutic effect through targeted PTT/PDT. In particular, the thermal effect can not only boost the catalytic activity of urease but also achieve ideally anti-tumor effect. In addition, guided by and AIE PS, the nanomotor can generate 1O2 to achieve PDT and be traced in real time serving as an effective fluorescent bio-radar for intracellular self-reporting during cancer treatment. Finally, the targeting ability of MUHA is provided by hyaluronan. Taken together, this MHUA platform provides a simple and effective strategy for target/fluorescence radar detective-guided PTT/PDT combination, and achieves good therapeutic results without chemodrug under thermal accelerated strategy, providing a new idea for the construction of chemodrug-free nanomotor-therapy system.

Algae-Based Supplements Claiming Weight Loss Properties: Authenticity Control and Scientific-Based Evidence on Their Effectiveness.

The worldwide prevalence of obesity impacts more than 600 million adults. Successfully managing weight is effective in reducing the risk of chronic diseases, but sustaining long-term weight loss remains a challenge. Although there are supplements based on algae that claim to aid in weight loss, there is a notable scarcity of scientific evidence supporting their effectiveness, and their regular consumption safety remains inadequately addressed. In this work, commercially available Arthrospira (Spirulina) platensis Gomont and/or Fucus vesiculosus L. supplements showed moderate capacity to inhibit the activity of carbohydrate-metabolizing enzymes, and to scavenge biologically relevant reactive species. IC25 values varying between 4.54 ± 0.81 and 66.73 ± 5.91 µg of dry extract/mL and between 53.74 ± 8.42 and 1737.96 ± 98.26 µg of dry extract/mL were obtained for α-glucosidase and aldose reductase, respectively. A weaker effect towards α-amylase activity was observed, with a maximum activity of the extracts not going beyond 33%, at the highest concentrations tested. Spirulina extracts showed generally better effects than those from F. vesiculosus. Similar results were observed concerning the antiradical capacity. In a general way, the extracts were able to intercept the in vitro-generated reactive species nitric oxide (•NO) and superoxide anion (O2•-) radicals, with better results for O2•-scavenging with the spirulina samples (IC25 values of 67.16 and 122.84 µg of dry extract/mL). Chemically, similar pigment profiles were observed between spirulina supplements and the authenticated counterpart. However, fucoxanthin, the chemotaxonomic marker of brown seaweeds, was not found in F. vesiculosus samples, pointing to the occurrence of a degradation phenomenon before, during, or after raw material processing. Our findings can contribute to providing data to allow regulatory entities (e.g., EFSA and FDA) to better rule these products in a way that can benefit society.

Comparison of Cd, Cu, Se, and Zn Concentration in the Muscle and Hepatopancreas of Sepia pharaonis and Uroteuthis duvauceli in the North of Persian Gulf (Iran).

The objective of this research was to examine and contrast the levels of cadmium (Cd), copper (Cu), zinc (Zn), and selenium (Se) in the muscle and hepatopancreas tissues of two species, namely pharaoh cuttlefish (Sepia pharaonis) and Indian squid (Uroteuthis duvauceli), from the Persian Gulf. A total of thirty individuals of each species were gathered in January 2009 from the northern waters of the Persian Gulf. The metal concentrations were significantly higher in muscle tissue (p < 0.05) than in other tissues. S. pharaonis had higher metal concentrations than U. duvauceli. In the muscle and hepatopancreas samples of S. pharaonis, the highest mean concentrations were found to be for Zn (58.45 ± 0.96 µg/g dw) and Cu (1541.47 ± 192.15 µg/g dw), respectively. In U. duvauceli, the highest concentration of measured elements was seen for Zn in both muscle (36.52 ± 0.56 µg/g dw) and hepatopancreas (60.94 ± 2.65 µg/g dw). Se had the lowest concentration among the elements measured in both species. There was a negative and significant correlation between Cu and biometrical factors (total body length and weight) in both muscle and hepatopancreas samples of S. pharaonic and only in the muscle samples of U. duvauceli (p < 0.01, R2 = - 052; p < 0.01, R2 = - 0.055). However, there was a strong correlation between Zn and biometrical factors in hepatopancreas samples of both species. The comparison of metal concentrations with standards revealed that only Cd levels in S. pharaonis exceeded the ESFA and WHO standards, whereas other metals were below the standards.

The Experimental Development of Emulsions Enriched and Stabilized by Recovering Matter from Spirulina Biomass: Valorization of Residue into a Sustainable Protein Source.

Spirulina consists of a cluster of green-colored cyanobacteria; it is commonly consumed as a food or food supplement rich in bioactive compounds with antioxidant activity, predominantly C-phycocyanin (C-PC), which is related to anti-inflammatory action and anticancer potential when consumed frequently. After C-PC extraction, the Spirulina residual biomass (RB) is rich in proteins and fatty acids with the potential for developing food products, which is interesting from the circular economy perspective. The present work aimed to develop a vegan oil-in-water emulsion containing different contents of Spirulina RB, obtaining a product aligned with current food trends. Emulsions with 3.0% (w/w) of proteins were prepared with different chickpea and Spirulina RB ratios. Emulsifying properties were evaluated regarding texture and rheological properties, color, antioxidant activity, and droplet size distribution. The results showed that it was possible to formulate stable protein-rich emulsions using recovering matter rich in protein from Spirulina as an innovative food ingredient. All the concentrations used of the RB promoted the formulation of emulsions presenting interesting rheological parameters compared with a more traditional protein source such as chickpea. The emulsions were also a source of antioxidant compounds and maintained the color for at least 30 days after production.

1-O-alkyl-glycerols from Squid Berryteuthis magister Reduce Inflammation and Modify Fatty Acid and Plasmalogen Metabolism in Asthma Associated with Obesity.

Asthma associated with obesity is considered the most severe phenotype and can be challenging to manage with standard medications. Marine-derived 1-O-alkyl-glycerols (AGs), as precursors for plasmalogen synthesis, have high biological activity, making them a promising substance for pharmacology. This study aimed to investigate the effect of AGs from squid Berryteuthis magister on lung function, fatty acid and plasmalogen levels, and cytokine and adipokine production in obese patients with asthma. The investigational trial included 19 patients with mild asthma associated with obesity who received 0.4 g of AGs daily for three months in addition to their standard treatment. The effects of AGs were evaluated at one and three months of treatment. The results of the study demonstrated that intake of AGs increased the FEV1 and FEV1/VC ratios, and significantly decreased the ACQ score in 17 of the 19 patients after three months of treatment. The intake of AGs increased concentration of plasmalogen and n-3 PUFA in plasma, and modified leptin/adiponectin production by adipose tissue. The supplementation of AGs decreased the plasma levels of inflammatory cytokines (TNF-α, IL-4, and IL-17a), and oxylipins (TXB2 and LTB4), suggesting an anti-inflammatory property of AGs. In conclusion, 1-O-alkyl-glycerols could be a promising dietary supplement for improving pulmonary function and reducing inflammation in obese asthma patients, and a natural source for plasmalogen synthesis. The study highlighted that the beneficial effects of AG consumption can be observed after one month of treatment, with gradual improvement after three months of supplementation.

Investigation of the Potential of Selected Food-Derived Antioxidants to Bind and Stabilise the Bioactive Blue Protein C-Phycocyanin from Cyanobacteria Spirulina.

Blue C-phycocyanin (C-PC), the major Spirulina protein with innumerable health-promoting benefits, is an attractive colourant and food supplement. A crucial obstacle to its more extensive use is its relatively low stability. This study aimed to screen various food-derived ligands for their ability to bind and stabilise C-PC, utilising spectroscopic techniques and molecular docking. Among twelve examined ligands, the protein fluorescence quenching revealed that only quercetin, coenzyme Q10 and resveratrol had a moderate affinity to C-PC (Ka of 2.2 to 3.7 × 105 M-1). Docking revealed these three ligands bind more strongly to the C-PC hexamer than the trimer, with the binding sites located at the interface of two (αß)3 trimers. UV/VIS absorption spectroscopy demonstrated the changes in the C-PC absorption spectra in a complex with quercetin and resveratrol compared to the spectra of free protein and ligands. Selected ligands did not affect the secondary structure content, but they induced changes in the tertiary protein structure in the CD study. A fluorescence-based thermal stability assay demonstrated quercetin and coenzyme Q10 increased the C-PC melting point by nearly 5 °C. Our study identified food-derived ligands that interact with C-PC and improve its thermal stability, indicating their potential as stabilising agents for C-PC in the food industry.

[Squid fat as a promising source of polyunsaturated fatty acids].

Omega-3 polyunsaturated fatty acids (ω-3 PUFA) are substances that play an important role in human metabolism. They are essential nutritional factors and can improve the functioning of individual systems and the body as a whole. The main source of ω-3 PUFA has long been fish fat, which contains PUFA in the triglyceride form. A fairly new and promising alternative to fish fat is the liver fat of the Commander squid (Berryteuthis magister), which additionally contains alkylglycerols, contains PUFA in the phospholipid form and can be obtained from squid fishery waste. The objective of the research was to carry out an analysis of scientific data, including the results of studies of the biological activity of squid fat, as well as its components that are part of other similar raw materials, and evaluate the prospects for its use in medical practice. Material and methods. During the study, various sources were analyzed, including scientific literature from electronic databases eLibrary, PubMed, Scopus, Web of Science and electronic search engines Google Academy from 2000 to 2022. Results. It is noted that squid fat has a pronounced biological activity. Its components increase innate immunity, have antitumor potential, improve the state of the body under stress, have hypolipidemiс and hypotensive effect, improve memory and attention, and also positively affect the composition and rheological parameters of blood. In addition to these effects, a positive effect of ω-3 PUFA and alkylglycerols on spermatogenesis, sperm quality and the female reproductive system has been noted. In a number of studies, alkylglycerol esters increased the permeability of the blood-brain barrier and, due to their structure, are able to form vesicles, therefore, they can be considered as raw materials for the production of new dosage forms for targeted therapy of brain tumors. In the available literature, in the case of the use of squid fat and its components, undesirable side effects have not been identified. Conclusion. Squid fat is a complete source of ω-3 PUFA and alkylglycerols, therefore it can be recommended as a dietary supplement, especially in a diet low in ω-3 PUFA.

Commercial cuttlefish exposed to noise from offshore windmill construction show short-range acoustic trauma.

The installation of marine renewable energy devices (MREDs, wind turbines and converters of wave, tidal and ocean thermal energy) has increased quickly in the last decade. There is a lack of knowledge concerning the effects of MREDs on benthic invertebrates that live in contact with the seabed. The European common cuttlefish (Sepia officinalis) is the most abundant cephalopod in the Northeast Atlantic and one of the three most valuable resources for English Channel fisheries. A project to build an offshore wind farm in the French bay of Saint-Brieuc, near the English Channel, raised concern about the possible acoustic impact on local cuttlefish communities. In this study, consisting of six exposure experiments, three types of noise were considered: 3 levels of pile-driving and 3 levels of drilling. The objectives were to assess possible associated changes in hatching and larva survival, and behavioural and ultrastructural effects on sensory organs of all life stages of S. officinalis populations. After exposure, damage was observed in the statocyst sensory epithelia (hair cell extrusion) in adults compared to controls, and no anti-predator reaction was observed. The exposed larvae showed a decreased survival rate with an increasing received sound level when they were exposed to maximum pile-driving and drilling sound levels (170 dB re 1 µPa2 and 167 dB re 1 µPa2, respectively). However, sound pressure levels's lower than 163 dB re 1 µPa2 were not found to elicit severe damage. Simulating a scenario of immobile organisms, eggs were exposed to a combination of both pile driving and drilling as they would be exposed to all operations without a chance to escape. In this scenario a decrease of hatching success was observed with increasing received sound levels.

Monitoring of Spirulina Flakes and Powders from Italian Companies.

Microalgae and microalgae-derived compounds have great potential as supplements in the human diet and as a source of bioactive products with health benefits. Spirulina (Arthrospira platensis (Nordstedt) Gomont, or Spirulina platensis) belongs to the class of cyanobacteria and has been studied for its numerous health benefits, which include anti-inflammatory properties, among others. This work was aimed at comparing some spirulina products available on the Italian market. The commercial products here analyzed consisted of spirulina cultivated and processed with different approaches. Single-component spirulina products in powder and flake form, free of any type of excipient produced from four different companies operating in the sector, have been analyzed. The macro- and micromorphological examination, and the content of pigments, phycobiliproteins, phenols, and proteins have shown differences regarding the morphology and chemical composition, especially for those classes of particularly unstable compounds such as chlorophylls and carotenoids, suggesting a great influence of both culture conditions and processing methods.

Cuttlefish ink loaded polyamidoxime adsorbent with excellent photothermal conversion and antibacterial activity for highly efficient uranium capture from natural seawater.

Owing to the abundant uranium reserves in the oceans, the collection of uranium from seawater has aroused the widespread interest. Compared to the uranium extraction from ore, uranium collection from seawater is a more environmentally friendly strategy. The amidoxime (AO) functional group has been considered as one of the most efficient chelating groups for uranium capture. In this work, by drawing upon the photothermal character and antibacterial activity of cuttlefish ink, a cuttlefish ink loaded polyamidoxime (CI-PAO) membrane adsorbent is developed. Under one-sun illumination, the CI-PAO membrane shows a high extraction capacity of 488.76 mg-U/g-Ads in 500 mL 8 ppm uranium spiked simulated seawater, which is 1.24 times higher than PAO membrane. The adsorption rate of CI-PAO membrane is increased by 32.04%. Furthermore, exhibiting roughly 75% bacteriostatic rate in composite marine bacteria, the CI-PAO shows a dramatically antibacterial activity, which effectively prevents the functional sites on the adsorbent surface from being occupied by the biofouling blocks. After immersing in natural seawater for 4 weeks, light-irradiated CI-PAO gave high uranium uptake capacity of 6.17 mg-U/g-Ads. Hence, the CI-PAO membrane adsorbent can be considered as a potential candidate for the practical application for uranium extraction from seawater.

Effects of ammonia toxicity on the histopathology, detoxification, oxidative stress, and immune response of the cuttlefish Sepia pharaonis and the mitigation of γ-aminobutyric acid.

In this study, γ-aminobutyric acid (GABA) was examined as an additional supplement to improve the ammonia stress resistance of S. pharaonis. Specifically, we added different doses of GABA (0, 20, 40, 60, 80, and 100 mg/kg) to food, cultivated S. pharaonis in regular seawater for 8 weeks and then in 8.40 mg/L ammonia seawater for 48 h and then investigated the accumulation of ammonia (the hepatic ammonia content), ammonia detoxification process (the urea content), antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT) enzyme activities), immune response (the serum haemolytic complement (C3) and lysozyme (LYZ) contents), membrane lipid peroxidation (malondialdehyde (MDA)) and histopathology of the liver. The results showed that ammonia poisoning could induce ammonia and MDA accumulation and subsequently lead to oxidative stress (decreases in SOD and CAT activities), immunosuppression (reductions in the haemolytic C3 and LYZ content), and histopathological injury in the liver. The application of GABA had a significant effect on alleviating the adverse effect of ammonia poisoning, and 80-100 mg/kg treatment exerted the best effect. This treatment significantly reduced the ammonia and MDA contents, significantly increased the urea content, increased the SOD, CAT, C3 and LYZ activities, reduced the MDA content, suppressed membrane lipid peroxidation, and significantly improved the histopathological injury to the liver. In summary, the results could provide a new method for mitigating liver damage, alleviating the physiological and metabolic disorders caused by ammonia stress in cuttlefish, and provide a theoretical basis for the application of GABA in alleviating ammonia poisoning.

Para-Aminobenzoic Acid, Calcium, and c-di-GMP Induce Formation of Cohesive, Syp-Polysaccharide-Dependent Biofilms in Vibrio fischeri.

The marine bacterium Vibrio fischeri efficiently colonizes its symbiotic squid host, Euprymna scolopes, by producing a transient biofilm dependent on the symbiosis polysaccharide (SYP). In vitro, however, wild-type strain ES114 fails to form SYP-dependent biofilms. Instead, genetically engineered strains, such as those lacking the negative regulator BinK, have been developed to study this phenomenon. Historically, V. fischeri has been grown using LBS, a complex medium containing tryptone and yeast extract; supplementation with calcium is required to induce biofilm formation by a binK mutant. Here, through our discovery that yeast extract inhibits biofilm formation, we uncover signals and underlying mechanisms that control V. fischeri biofilm formation. In contrast to its inability to form a biofilm on unsupplemented LBS, a binK mutant formed cohesive, SYP-dependent colony biofilms on tTBS, modified LBS that lacks yeast extract. Moreover, wild-type strain ES114 became proficient to form cohesive, SYP-dependent biofilms when grown in tTBS supplemented with both calcium and the vitamin para-aminobenzoic acid (pABA); neither molecule alone was sufficient, indicating that this phenotype relies on coordinating two cues. pABA/calcium supplementation also inhibited bacterial motility. Consistent with these phenotypes, cells grown in tTBS with pABA/calcium were enriched in transcripts for biofilm-related genes and predicted diguanylate cyclases, which produce the second messenger cyclic-di-GMP (c-di-GMP). They also exhibited elevated levels of c-di-GMP, which was required for the observed phenotypes, as phosphodiesterase overproduction abrogated biofilm formation and partially rescued motility. This work thus provides insight into conditions, signals, and processes that promote biofilm formation by V. fischeri. IMPORTANCE Bacteria integrate environmental signals to regulate gene expression and protein production to adapt to their surroundings. One such behavioral adaptation is the formation of a biofilm, which can promote adherence and colonization and provide protection against antimicrobials. Identifying signals that trigger biofilm formation and the underlying mechanism(s) of action remain important and challenging areas of investigation. Here, we determined that yeast extract, commonly used for growth of bacteria in laboratory culture, inhibits biofilm formation by Vibrio fischeri, a model bacterium used for investigating host-relevant biofilm formation. Omitting yeast extract from the growth medium led to the identification of an unusual signal, the vitamin para-aminobenzoic acid (pABA), that when added together with calcium could induce biofilm formation. pABA increased the concentrations of the second messenger, c-di-GMP, which was necessary but not sufficient to induce biofilm formation. This work thus advances our understanding of signals and signal integration controlling bacterial biofilm formation.

Mercury and selenium in squids from the Pacific Ocean and Indian Ocean: The distribution and human health implications.

Squids are globally distributed. Hg-contaminated squids may have high risks on humans. With abundant Se (antagonistic effect on Hg), the risks can be reduced. We collected squids around the world (Northwest Pacific Ocean, Southeast Pacific Ocean and Indian Ocean). Concentrations of Hg and Se were region-based and tissue-based. The higher content of Se were, the lower relative Hg levels were. The correlation between Se:Hg and Se was the strongest in the digestive gland. The values of Se:Hg and THQ all confirm that the health risk was lower in samples with higher concentrations of Se. Despite the risk assessment by Se:Hg, BRV and THQ analysis showed no risk when consumed in moderation, the maximum daily intake is provided based on Monte Carlo simulation. In future, when evaluating the risks cause by Hg exposure and providing the recommended daily amount, it may need to concurrent consideration of Se levels.

Eco-friendly isolation and characterization of nanochitin from different origins by microwave irradiation: Optimization using response surface methodology.

The extraction of nanochitin from marine waste has attracted great industrial interest due to its unique properties, namely biodegradability, biocompatibility and as a functional reinforcing agent. Conventional acid hydrolysis isolation of nanochitin requires high temperatures and acid concentration, time and energy. Herein, for the first time, microwave irradiation method was used as an eco-friendly approach to isolate nanochitin from different sources. The isolation conditions were optimized through an experimental Box-Behnken design using surface response methodology. The data showed optimal conditions of 1 M HCl, 10.00 min and 124.75 W to obtain lobster nanocrystals; 1 M HCl, 14.34 min and 50.21 W to obtain shrimp nanocrystals; and 1 M HCl, 29.08 min and 54.08 W to obtain squid pen nanofibres, reducing time and HCl concentration. The obtained isolation yields where of 85.30, 79.92 and 80.59 % for lobster, shrimp and squid, respectively. The morphology of the nanochitins was dependent of the chitin origin, and the lengths of the nanochitins were of 314.74, 386.12 and > 900 nm for lobster, shrimp and squid pen, respectively. The thermal stability of the ensuing nanochitins was maintained after treatment. The results showed that nanochitin could be obtained by using an eco-friendly approach like microwave irradiation.

Valorization of food waste to produce intelligent nanofibrous ß-chitin films.

The efficient use of waste from food processing industry is one of the innovative approaches within sustainable development, because it can be transferred into added value products, which could improve economic, energetic and environmental sectors. In this context, the squid pen waste from seafood industry was used as raw material to obtain nanofibrous ß-chitin films. In order to extend functionality of obtained films, elderberry extract obtained from biomass was added at different concentrations. The tensile strength of chitin-elderberry extract films was improved by 52%, elongation at break by 153% and water vapor barrier by 65%. The obtained material showed distinct color change when subjected to acidic or basic solutions. It was proven by CIELab color analysis that all color changes could be easily perceived visually. In addition, the obtained nanofibrous film was successfully used to monitor the freshness of Hake fish. Namely, when the film was introduced in a package that contained fresh fish, its color was efficiently changed within the time during the storage at 4 °C. The obtained results demonstrated that food processing waste could be efficiently valorized, and could give sustainable food package design as a spoilage indicator of high protein food.

A resonant squid-inspired robot unlocks biological propulsive efficiency.

Elasticity has been linked to the remarkable propulsive efficiency of pulse-jet animals such as the squid and jellyfish, but reports that quantify the underlying dynamics or demonstrate its application in robotic systems are rare. This work identifies the pulse-jet propulsion mode used by these animals as a coupled mass-spring-mass oscillator, enabling the design of a flexible self-propelled robot. We use this system to experimentally demonstrate that resonance greatly benefits pulse-jet swimming speed and efficiency, and the robot's optimal cost of transport is found to match that of the most efficient biological swimmers in nature, such as the jellyfish Aurelia aurita The robot also exhibits a preferred Strouhal number for efficient swimming, thereby bridging the gap between pulse-jet propulsion and established findings in efficient fish swimming. Extensions of the current robotic framework to larger amplitude oscillations could combine resonance effects with optimal vortex formation to further increase propulsive performance and potentially outperform biological swimmers altogether.

Interaction of Squid (Dosidicus giga) Mantle Protein with a Mixtures of Potato and Corn Starch in an Extruded Snack, as Characterized by FTIR and DSC.

The majority of snacks expanded by extrusion (SEE) are made with vegetable sources, to improve their nutritional content; it has been proposed to incorporate squid (Dosidicus gigas), due to its high protein content, low price and high availability. However, the interaction of proteins of animal origin with starch during extrusion causes negative effects on the sensory properties of SEE, so it is necessary to know the type of protein-carbohydrate interactions and their effect on these properties. The objective of this research was to study the interaction of proteins and carbohydrates of SEE elaborated with squid mantle, potato and corn. The nutritional composition and protein digestibility were evaluated, Fourier transform infrared (FTIR) and Differential Scanning Calorimetry (DSC) were used to study the formation of protein-starch complexes and the possible regions responsible for their interactions. The SEE had a high protein content (40-85%) and biological value (>93%). The melting temperature (Tm) was found between 145 and 225 °C; the Tm values in extruded samples are directly proportional to the squid content. The extrusion process reduced the amine groups I and II responsible for the protein-protein interaction and increased the O-glucosidic bonds, so these bonds could be responsible for the protein-carbohydrate interactions.

In silico evaluation of marine fish proteins as nutritional supplements for COVID-19 patients.

To date, no specific drug has been discovered for the treatment of COVID-19 and hence, people are in a state of anxiety. Thus, there is an urgent need to search for various possible strategies including nutritional supplementation. In this study, we have tried to provide a reference for protein supplementation. Specifically, 20 marine fish proteins were subjected to in silico hydrolysis by gastrointestinal enzymes, and a large number of active peptides were generated. Then, the binding abilities of these peptides to SARS-CoV-2 main protease and monoamine oxidase A were assessed. The results showed that NADH dehydrogenase could be a good protein source in generating potent binders to the two enzymes, followed by cytochrome b. In addition, some high-affinity oligopeptides (VIQY, ICIY, PISQF, VISAW, AIPAW, and PVSQF) were identified as dual binders to the two enzymes. In summary, the supplementation of some fish proteins can be helpful for COVID-19 patients; the identified oligopeptides can be used as the lead compounds to design potential inhibitors against COVID-19 and anxiety.

The mechanistic effect of bromelain and papain on tenderization in jumbo squid (Dosidicus gigas) muscle.

Jumbo squid (Dosidicus gigas) muscle is rather hard and tough, which directly affects consumer acceptance. In this study, the tenderization effect of bromelain and papain on squid muscle during enzymolysis is examined and compared with an untreated control and water-treated sample. Squid mantle were incubated with different solutions (water, bromelain, and papain solution) for 40 min in a 30 °C water bath. Then, the mantle samples were subjected to water holding capacity (WHC) analysis, texture evaluation, biochemical determination, and histological observations. The results revealed that bromelain and papain disadvantageously decrease the water holding capacity when compared to the control and water-treated samples. Furthermore, following tenderization with bromelain or papain, muscle hardness, shear force, myofibrillar protein content, and Ca2+ ATPase activity were all significantly decreased. Additionally, some essential amino acids were released following tenderization. When examining the myofibrillar fragmentation index (MFI), bromelain and papain were shown to cause high levels of hydrolysis in myofibrillar and sarcoplasmic proteins. Moreover, microstructural imaging indicated that the tenderization treatments disrupted myofibrils and generated a larger number of small fragments in the muscle tissues, subsequently decreasing microstructure stability and integrity. SDS-PAGE analysis confirmed that bromelain and papain have a high proteolytic activity, with some small peptides and/or short fragments detected post-tenderization. The results presented herein demonstrated that bromelain and papain improved squid muscle tenderness and can be utilized to ensure a more desirable squid product.

Transient pressure modeling in jetting animals.

There are many marine animals that employ a form of jet propulsion to move through the water, often creating the jets by expanding and collapsing internal fluid cavities. Due to the unsteady nature of this form of locomotion and complex body/nozzle geometries, standard modeling techniques prove insufficient at capturing internal pressure dynamics, and hence swimming forces. This issue has been resolved with a novel technique for predicting the pressure inside deformable jet producing cavities (M. Krieg and K. Mohseni, J. Fluid Mech., 769, 2015), which is derived from evolution of the surrounding fluid circulation. However, this model was only validated for an engineered jet thruster with simple geometry and relatively high Reynolds number (Re) jets. The purpose of this manuscript is twofold: (i) to demonstrate how the circulation based pressure model can be used to analyze different animal body motions as they relate to propulsive output, for multiple species of jetting animals, (ii) and to quantitatively validate the pressure modeling for biological jetting organisms (typically characterized by complicated cavity geometry and low/intermediate Re flows). Using jellyfish (Sarsia tubulosa) as an example, we show that the pressure model is insensitive to complex cavity geometry, and can be applied to lower Re swimming. By breaking down the swimming behavior of the jellyfish, as well as that of squid and dragonfly larvae, according to circulation generating mechanisms, we demonstrate that the body motions of Sarsia tubulosa are optimized for acceleration at the beginning of pulsation as a survival response. Whereas towards the end of jetting, the velar morphology is adjusted to decrease the energetic cost. Similarly, we show that mantle collapse rates in squid maximize propulsive efficiency. Finally, we observe that the hindgut geometry of dragonfly larvae minimizes the work required to refill the cavity. Date Received: 10-18-2019, Date Accepted: 99-99-9999 *kriegmw@hawaii.edu, UHM Ocean and Res Eng, 2540 Dole St, Honolulu, HI 96822.