Mantle Muscle Research Articles

Compartment-Specific Phosphorylation of Squid Neurofilaments.

Studies of the giant axon and synapse of third-order neurons in the squid stellate ganglion have provided a vast literature on neuronal physiology and axon transport. Large neuronal size also lends itself to comparative biochemical studies of cell body versus axon. These have focused on the regulation of synthesis, assembly, posttranslational modification and function of neuronal cytoskeletal proteins (microtubules (MTs) and neurofilaments (NFs)), the predominant proteins in axoplasm. These contribute to axonal organization, stability, transport, and impulse transmission responsible for rapid contractions of mantle muscles underlying jet propulsion. Studies of vertebrate NFs have established an extensive literature on NF structure, organization, and function; studies of squid NFs, however, have made it possible to compare compartment-specific regulation of NF synthesis, assembly, and function in soma versus axoplasm. Since NFs contain over 100 eligible sites for phosphorylation by protein kinases, the compartment-specific patterns of phosphorylation have been a primary focus of biochemical studies. We have learned that NF phosphorylation is tightly compartmentalized; extensive phosphorylation occurs only in the axonal compartment in squid and in vertebrate neurons. This extensive phosphorylation plays a key role in organizing NFs, in association with microtubules (MTs), into a stable, dynamic functional lattice that supports axon growth, diameter, impulse transmission, and synaptic activity. To understand how cytoskeletal phosphorylation is topographically regulated, the kinases and phosphatases, bound to NFs isolated from cell bodies and axoplasm, have also been studied.

Enrichment of Adult Artemia Biomass and Squid Mantle Muscle, Dosidicus gigas, with Different Ascorbic Acid (L‐Ascorbyl‐2‐Monophosphate‐Na/Ca) Concentrations

AbstractL‐ascorbyl‐2‐monophosphate‐Na/Ca (AMP‐Na/Ca) was used as a vitamin C source to investigate its ascorbic acid (L‐AA) enrichment and retention in boosted Artemia biomass (AB) and squid mantle muscle (SM). Different doses of AMP‐Na/Ca (500, 1000, and 1500 AMP‐Na/Ca mg/kg) were gradually dissolved into the culture tanks at time 0 (T0) and at each hour until Hour 6 (T6). Samples of AB and SM were taken for AMP‐Na/Ca and L‐AA analysis at T0, T1, T2, T3, T4, T5, T6, T12, and T24. There were no significant differences (P > 0.05) among the AB groups at T1. The T6 enrichment analysis for AB resulted in significant differences (P < 0.05) in the AMP‐Na/Ca content for the 1500 mg/kg treatment, in which the initial concentration (0.001 ± 0.002 mg/kg) increased by more than 16‐fold. For all AB enrichment treatments, the AMP‐Na/Ca content demonstrated a decrease (32–11%) for the T6, T12 and T24 analysis. The T1 analysis for SM at the higher AMP‐Na/Ca enrichment concentration registered 30 mg/kg of L‐AA and decreased (27.6%) at T6. This study demonstrated that AB and SM can be boosted with AMP‐Na/Ca.

I-5. スルメイカ肉構成タンパク質と内在性メタロプロテアーゼ

I-5. スルメイカ肉構成タンパク質と内在性メタロプロテアーゼ

Mechanism study of high browning degree of mantle muscle meat from Japanese common squid Todarodes pacificus during air-drying

Mantle meat from the Japanese common squid (Todarodes pacificus) browns more than other squid meats during air-drying. The factors contributing to the browning of Japanese common squid, long-finned squid (Photololigo edulis) and bigfin reef squid (Sepioteuthis lessoniana) were studied in boiled and raw meat both before and after air-drying. Dried raw meat from the Japanese common squid browned more than dried boiled meat (b∗ value, from 4.7 to 28.5). The results from SDS–PAGE showed significant degradation of myosin heavy chain (MHC) suggesting that protease activity in raw Japanese common squid meat was higher than in the other two species. The concentration of arginine (1932.0mg/100g) and ribose (28.8μmol/g) in Japanese common squid meat was higher than in the other two species. These results suggest that high protease activity and high concentrations of arginine and ribose increase the browning discoloration of Japanese common squid during air-drying.

Alterations in the mantle epithelium during transition from hatching gland to adhesive organ of Idiosepius pygmaeus (Mollusca, Cephalopoda)

Epithelial gland systems play an important role in marine molluscs in fabricating lubricants, repellents, fragrances, adhesives or enzymes. In cephalopods the typically single layered epithelium provides a highly dynamic variability and affords a rapid rebuilding of gland cells. While the digestive hatching gland (also named Hoyle organ) is obligatory for most cephalopods, only four genera (Nautilus, Sepia, Euprymna and Idiosepius) produce adhesive secretions by means of glandular cells in an adhesive area on the mantle or tentacles. In Idiosepius this adhesive organ is restricted to the posterior part of the fin region on the dorsal mantle side and well developed in the adult stage. Two gland cell types could be distinguished, which produce different contents of the adhesive. During the embryonic development the same body area is occupied by the temporary hatching gland. The question arises, in which way the hatching gland degrades and is replaced by the adhesive gland.Ultrastructural analyses as well as computer tomography scans were performed to monitor the successive post hatching transformation in the mantle epithelium from hatching gland degradation to the formation of the adhesive organ. According to our investigations the hatching gland cells degrade within about 1 day after hatching by a type of programmed cell death and leave behind a temporary cellular gap in this area. First glandular cells of the adhesive gland arise 7 days after hatching and proceed evenly over the posterior mantle epithelium. In contrast, the accompanying reduction of a part of the dorsal mantle musculature is already established before hatching. The results demonstrate a distinct independence between the two gland systems and illustrate the early development of the adhesive organ as well as the corresponding modifications within the mantle.

Developmental dynamics of myogenesis in the shipworm Lyrodus pedicellatus (Mollusca: Bivalvia).

BackgroundThe shipworm Lyrodus pedicellatus is a wood-boring bivalve with an unusual vermiform body. Although its larvae are brooded, they retain the general appearance of a typical bivalve veliger-type larva. Here, we describe myogenesis of L. pedicellatus revealed by filamentous actin labelling and discuss the data in a comparative framework in order to test for homologous structures that might be part of the bivalve (larval) muscular ground pattern.ResultsFive major muscle systems were identified: a velum retractor, foot retractor, larval retractor, a distinct mantle musculature and an adductor system. For a short period of larval life, an additional ventral larval retractor is present. Early in development, a velum muscle ring and an oral velum musculature emerge. In late stages the lateral and dorsal mantle musculature, paired finger-shaped muscles, an accessory adductor and a pedal plexus are formed. Similar to other bivalve larvae, L. pedicellatus exhibits three velum retractor muscles, but in contrast to other species, one of them disappears in early stages of L. pedicellatus. The remaining two velum retractors are considerably remodelled during late larval development and are most likely incorporated into the elaborate mantle musculature of the adult.ConclusionsTo our knowledge, this is the first account of any larval retractor system that might contribute to the adult bodyplan of a (conchiferan) mollusk. A comparative analysis shows that a pedal plexus, adductors, a larval velum ring, velum retractors and a ventral larval retractor are commonly found among bivalve larvae, and thus most likely belong to the ground pattern of the bivalve larval musculature.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-014-0090-9) contains supplementary material, which is available to authorized users.

Effect of freezing on protein denaturation and gelling capacity of jumbo squid (Dosidicus gigas) mantle muscle

The effect of freezing storage on protein denaturation and gelling capacity of jumbo squid muscle was evaluated. Squid mantle muscle samples were evaluated in both, ground (G) and whole presentations (W), and in a control consisting of ground muscle (C). G and W samples were submitted to two freezing storage periods (−20 °C), 1 day (GF-1, WF-1) and 30 d (GF-30, WF-30). Proximate composition, pH, surface hydrophobicity (SoANS) and differential scanning calorimetry (DSC) were evaluated. Additionally folding test, texture profile analysis and water holding capacity were monitored in gels prepared with the different samples. The quality of gels was not affected by any treatment. Neither freezing, grinding or storage period had a significant effect on the above parameters, suggesting that functional properties of the squid mantle muscle are highly stable. DSC did not reveal any denaturation, also adducing high stability of muscle proteins. SoANS revealed that freezing, grinding and time, had an effect on protein properties; however, these influences were apparently not significantly enough to have a further effect on the gel quality. Finally, gelling capacity of muscle was not affected by any factor. Considering these results, squid muscle may be considered as a useful resource either fresh or frozen.

Insights into the organization of plumatellid larvae (lophotrochozoa, Bryozoa) by means of 3D-imaging and confocal microscopy.

Within the Lophotrochozoa, the Bryozoa or Ectoprocta remain one of the phyla whose phylogenetic relation to other lophotrochozoans is still controversely discussed. To complement existing data and to gain more insight into bryozoan character evolution, we analyzed the morphology of the larva of the phylactolaemate Plumatella sp. The larva of Plumatella spp. consists of an outer ciliated mantle that covers two differentiated polypides. The muscular and serotonergic nervous system of the polypides correspond to previous studies. The two polypides and their corresponding buds differ in size, which, together with a comparison among bryozoans, indicates that a single polypide is the basal condition. The whole larval mantle and mantle fold are supplied with circular and longitudinal muscles, the former being more pronounced in the mantle fold. The apical plate on the anterior side contains a diffuse mesh of crossing fibers and thus differs from previous descriptions, which recognized a regular muscular grid. The serotonergic nervous system in the mantle and mantle fold consists of a diffuse basiepidermal nerve net with its highest concentration at the apical plate. Serotonin immunoreactivity so far has not been detected in the mantle fold. However, the presence of other neurotransmitters in the mantle fold shown by previous studies indicates that this nerve net is a common feature of phylactolaemate larvae. The main difference between currently analyzed phylactolaemate larvae seems to be the complexity of the larval mantle musculature, which most likely plays an important role during metamorphosis. This study confirms previous interpretations that the apical plate pole does not correspond to the apical pole of gymnolaemate larvae but to their oral side. Accelerated asexual development on the aboral pole leads to the suggestion that an apical organ is never formed and the apical plate compensates for its absence in the free-swimming period.

Molecular characterization and gene expression analysis of a metalloprotease from Pacific abalone Haliotis discus hannai

We isolated a metalloprotease (MP) homologue from an abalone muscle cDNA library. A 3284-kb full-length cDNA encoding a predicted polypeptide of 667 amino acids was sequenced. The abalone MP Haliotis discus hannai (HdMP) exhibited a domain structure typical of the peptidase M4 family, a 21-amino acid N-terminal hydrophobic signal sequence followed by a long propeptide sequence of 347 amino acids and the mature protease domain comprising 299 amino acids. The mature region contains features characteristic of a zinc protease, including a zinc-binding motif (HEXXH) and an active site. The protein showed 32–38% amino acid sequence identity with other known MP sequences and with a hypothetical protein from owl limpet. The mRNA transcript is expressed in almost all tissues, with high expression in the mantle and adductor muscle of healthy abalones, and is expressed constitutively during the early developmental stages after fertilization. Lipopolysaccharide or poly I:C stimulation induced the expression of the HdMP transcript in the digestive track and gills of abalones. Collectively, these results suggest that HdMP could play multiple roles in defense, the immune response, growth, and regulation of reproduction.

Spray-Drying Effect of the Soluble Solids from an Effluent Produced by Cooking Jumbo Squid (Dosidicusgigas) Mantle Muscle

Cooking jumbo squid (Dosidicusgigas) muscle produces high organic-matter effluents, potentially pollutant for the environment. Effluent composition and physicochemical properties of solids recovered by freeze drying and spray drying were evaluated after being ultrafiltrated through 30 and 1 kDa cut-off membranes. Ultrafiltration reduced chemical and biochemical oxygen demands (99.8% and 99.4%, respectively). Hue angle and whiteness index were affected (p < 0.05) by drying temperature but not by atomizer rotation rate. Amino acid concentration was inversely affected as temperature and atomizer rotation rate increased, while nucleotides were reduced by heating. Squid cooking effluent showed valuable components that can be used by the food industry.

Developmental dynamics of myogenesis in the shipworm Lyrodus pedicellatus (Mollusca: Bivalvia)

BackgroundThe shipworm Lyrodus pedicellatus is a wood-boring bivalve with an unusual vermiform body. Although its larvae are brooded, they retain the general appearance of a typical bivalve veliger-type larva. Here, we describe myogenesis of L. pedicellatus revealed by filamentous actin labelling and discuss the data in a comparative framework in order to test for homologous structures that might be part of the bivalve (larval) muscular ground pattern.ResultsFive major muscle systems were identified: a velum retractor, foot retractor, larval retractor, a distinct mantle musculature and an adductor system. For a short period of larval life, an additional ventral larval retractor is present. Early in development, a velum muscle ring and an oral velum musculature emerge. In late stages the lateral and dorsal mantle musculature, paired finger-shaped muscles, an accessory adductor and a pedal plexus are formed. Similar to other bivalve larvae, L. pedicellatus exhibits three velum retractor muscles, but in contrast to other species, one of them disappears in early stages of L. pedicellatus. The remaining two velum retractors are considerably remodelled during late larval development and are most likely incorporated into the elaborate mantle musculature of the adult.ConclusionsTo our knowledge, this is the first account of any larval retractor system that might contribute to the adult bodyplan of a (conchiferan) mollusk. A comparative analysis shows that a pedal plexus, adductors, a larval velum ring, velum retractors and a ventral larval retractor are commonly found among bivalve larvae, and thus most likely belong to the ground pattern of the bivalve larval musculature.

Metabolic suppression during protracted exposure to hypoxia in the jumbo squid, Dosidicus gigas, living in an oxygen minimum zone.

The jumbo squid, Dosidicus gigas, can survive extended forays into the oxygen minimum zone (OMZ) of the Eastern Pacific Ocean. Previous studies have demonstrated reduced oxygen consumption and a limited anaerobic contribution to ATP production, suggesting the capacity for substantial metabolic suppression during hypoxic exposure. Here, we provide a more complete description of energy metabolism and explore the expression of proteins indicative of transcriptional and translational arrest that may contribute to metabolic suppression. We demonstrate a suppression of total ATP demand under hypoxic conditions (1% oxygen, PO2 =0.8 kPa) in both juveniles (52%) and adults (35%) of the jumbo squid. Oxygen consumption rates are reduced to 20% under hypoxia relative to air-saturated controls. Concentrations of arginine phosphate (Arg-P) and ATP declined initially, reaching a new steady state (~30% of controls) after the first hour of hypoxic exposure. Octopine began accumulating after the first hour of hypoxic exposure, once Arg-P breakdown resulted in sufficient free arginine for substrate. Octopine reached levels near 30 mmol g(-1) after 3.4 h of hypoxic exposure. Succinate did increase through hypoxia but contributed minimally to total ATP production. Glycogenolysis in mantle muscle presumably serves to maintain muscle functionality and balance energetics during hypoxia. We provide evidence that post-translational modifications on histone proteins and translation factors serve as a primary means of energy conservation and that select components of the stress response are altered in hypoxic squids. Reduced ATP consumption under hypoxia serves to maintain ATP levels, prolong fuel store use and minimize the accumulation of acidic intermediates of anaerobic ATP-generating pathways during prolonged diel forays into the OMZ. Metabolic suppression likely limits active, daytime foraging at depth in the core of the OMZ, but confers an energetic advantage over competitors that must remain in warm, oxygenated surface waters. Moreover, the capacity for metabolic suppression provides habitat flexibility as OMZs expand as a result of climate change.

Design and Mechanical Property of a Biomimetic Pulsatile Jet Propeller Inspired by Cuttlefish Actuated by SMA Wires

An experimental biomimetic pulsatile jet propeller for robot cuttlefish is presented. Firstly the mechanism of jet swimming of cuttlefish and their mantle muscle structure was analyzed. Secondly the pulsatile jet propeller which is actuated by SMA wires was designed. Then the mechanical properties of the propeller were tested through experiment. The experimental result shows that the propeller can generate thrust force and the maximum thrust force can reach 600 mN. At last, the swimming experiments are carried out and the maximum swimming speed is 8.7 cm/s.

Characterization of nautiloid orders Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida: new superorder Multiceratoidea

Multiple scars of shell muscles in the body chamber are characterized in five Palaeozoic nautiloid orders: Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida. The number of the scars is highly variable, from about 5 pairs in tarphycerids to about 60 pairs in ascocerids. The shell muscles that were attached to the scars in ellesmerocerids, oncocerids, dicosorids and ascocerids are here interpreted as the longitudinal mantle muscles and not as the head/funnel muscles. The interpretation of the multiple scars in tarphycerids is still unclear. In all five orders, the connecting ring structure is of the Nautilus type. The outer spherulitic-prismatic layer of the connecting ring is much thicker than that of the layer in Nautilus. It is highly porous in ellesmerocerids, oncocerids and tarphycerids and similar to that in Nautilus, but less porous and more dense in discosorids and ascocerids. The inner fibrous-organic layer of the connecting ring in all five orders is not preserved, but it has probably been considerably thinner than that in Nautilus. In some oncocerid taxa, the siphuncle contains actinosiphonate deposits of complicated structure. The ontogenetic growth of these deposits is reconstructed. On the basis of the presence of multiple muscle scars and the Nautilus type of connecting ring, the ellesmerocerids, oncocerids, discosorids and ascocerids are included in the new superorder Multiceratoidea. It is still unclear whether tarphycerids also belong to this superorder.

Some metal concentrations in the edible parts of Tridacna maxima, Red Sea, Egypt

The concentrations of Ca, some essential (Fe, Zn, Mn, and Cu) and non-essential nutritive elements (Cd, Pb, and Ni) were measured in the edible parts (mantle and adductor muscles) of Tridacna maximx collected from south Quseir City (Red Sea). The general trend of metal contents of the different parts follows the order; Ca > Fe > Zn > Pb > Mn > Cu > Cd > Ni. The tissues before cooking recorded the highest average concentrations of Cu, Pb, Fe, Cd, Mn, and Ni (2.658, 5.250, 34.375, 1.464, 3.207, and 0.886 ppm, respectively) relative to tissues after cooking and the water of cooked tissues (WCT). The total cooked tissues recorded higher average contents of Zn and Ca (17.282 and 1,114.679 ppm) than the uncooked tissues. Calcium recorded the highest concentration in the ECT of adductor and mantle muscles (2,081.126 ± 177.39 and 1,893.326 ± 394.28 ppm). Mantle recorded higher concentrations of Pb, Mn, Ni, and Ca (7.489 ± 4.65, 4.241 ± 1.13, 0.980 ± 0.60, and 1,039.362 ± 177.42 ppm, respectively) than adductor muscle before cooking. Ca concentration levels in the WCT increased after cooking tissues especially in adductor muscles. This may attributed to the liberation of larger amount of calcium in ionic form in water. The clams may have intracellular regulatory mechanisms to keep their concentrations in equilibrium, subsequently; the recorded metal concentrations are in the safe limits for human consuming, where these concentrations did not exceed the clam’s capacity of regulation.

Transmural variation in the length‐force relationships and in vivo operating length ranges of the mantle muscles of squid

Recent work has shown that contraction of hollow, cylindrical, muscular organs is accompanied by significant non‐uniformities in circumferential strain across the muscular body wall. In squid, circumferential strain along the inner surface of the mantle wall is 1.3 to 1.6 times greater during the mantle contractions used to power jet locomotion than along the outer surface of the mantle. This transmural gradient of strain may result in the circular muscle fibers from near the inner and outer surfaces of the mantle operating over different regions of the length‐tension curve during the same mantle contraction cycle, potentially generating different instantaneous forces. We used sonomicrometry on swimming squid and isometric tests on bundles of circular fibers to test the hypothesis that circular muscle contractile properties vary transmurally in the mantle in the Atlantic longfin squid, Doryteuthis pealeii. We found that the length‐force relationship of the obliquely striated circular muscle fibers varied significantly with radial position in the mantle wall. Sonomicrometry experiments revealed that the circular fibers operated in vivo primarily along the entire ascending limb of the length‐tension curve. Our work shows that the functional diversity of obliquely striated muscles is much greater than previously thought. Supported by NSF grant IOS‐0950827.

The Adaptive Response of Protein Turnover to the Energetic Demands of Reproduction in a Cephalopod

Sourcing energy for reproduction is a major driver of the life-history characteristics of animals. Unlike other molluscs, cephalopods do not appear to have significant glycogen stores, and energy is either sourced directly from ingested food or mobilized from protein stores in the muscle. Given the importance of protein to cephalopods, this study quantified changes in protein turnover in the muscle tissue in reproductively immature and maturing/mature individuals. Quantifying protein accretion and protein synthesis allowed an assessment of protein turnover in immature and maturing individuals of the southern dumpling squid (Euprymna tasmanica), which has fast nonasymptotic growth, has a short generation time, and does not use lipid stores. This study found that protein turnover slowed in the mantle muscle tissue with gonad growth, suggesting an adaptive response to the energy demands associated with reproduction but one that allows for continued somatic growth and muscle function in these animals. However, the cost of reproduction may be indirect, with less energy available for somatic repair, and therefore may be responsible for the rapid senescence typical of many cephalopod species.

The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones I: Oxygen consumption rates and critical oxygen partial pressures

Dosidicus gigas is a large, metabolically active, epipelagic squid known to undertake diel vertical migrations across a large temperature and oxygen gradient in the Eastern Pacific. Hypoxia is known to cause metabolic suppression in D. gigas. However, the precise oxygen level at which metabolic suppression sets in is unknown. Here we describe a novel ship-board swim tunnel respirometer that was used to measure metabolic rates and critical oxygen partial pressures (Pcrit) for adult squids (2–7kg). Metabolic rate measurements were validated by comparison to the activity of the Krebs cycle enzyme, citrate synthase, in mantle muscle tissue (2–17kg). We recorded a mean routine metabolic rate of 5.91μmolg−1h−1 at 10°C and 12.62μmolg−1h−1 at 20°C. A temperature coefficient, Q10, of 2.1 was calculated. D. gigas had Pcrits of 1.6 and 3.8kPa at 10 and 20°C, respectively. Oxygen consumption rate (MO2) varied with body mass (M) according to MO2=11.57M−0.12±0.03 at 10°C. Citrate synthase activity varied with body mass according to Y=9.32M−0.19±0.02.

Mechanisms of protein degradation in mantle muscle and proposed gill remodeling in starvedSepia officinalis

Cephalopods have relatively high rates of protein synthesis compared to rates of protein degradation, along with minimal carbohydrate and lipid reserves. During food deprivation on board protein is catabolized as a metabolic fuel. The aim of the current study was to assess whether biochemical indices of protein synthesis and proteolytic mechanisms were altered in cuttlefish, Sepia officinalis, starved for 7 days. In mantle muscle, food deprivation is associated with a decrease in protein synthesis, as indicated by a decrease in the total RNA level and dephosphorylation of key signaling molecules, such as the eukaryote binding protein, 4E-BP1 (regulator of translation) and Akt. The ubiquitination-proteasome system (UPS) is activated as shown by an increase in the levels of proteasome β-subunit mRNA, polyubiquitinated protein, and polyubiquitin mRNA. As well, cathepsin activity levels are increased, suggesting increased proteolysis through the lysosomal pathway. Together, these mechanisms could supply amino acids as metabolic fuels. In gill, the situation is quite different. It appears that during the first stages of starvation, both protein synthesis and protein degradation are enhanced in gill. This is based upon increased phosphorylation of 4E-BP1 and enhanced levels of UPS indicators, especially 20S proteasome activity and polyubiquitin mRNA. It is proposed that an increased protein turnover is related to gill remodeling perhaps to retain essential hemolymph-borne compounds.

Stability of the Physical Properties of Plasticized Edible Films from Squid (Todarodes pacificus) Mantle Muscle during Storage

Edible films from squid mantle muscle plasticized with different plasticizers were stored at 25 °C, 50% RH before the determination of physical properties. The results showed that tensile strength significantly increased (P < 0.05) upon the storage time, especially for the film plasticized with glucose, while there was no significant change (P ≥ 0.05) in elongation at break of all plasticized films. Water vapor permeability of glucose-plasticized film significantly decreased (P < 0.05) during storage, while there was only a slight change in those with glycerol, sorbitol, and fructose. Redness and yellowness of the films became significantly higher (P < 0.05) during storage, especially for the films plasticized with fructose and glucose. SDS-PAGE and protein solubility in SDS solution showed a possibility of protein aggregation throughout the storage. From these results, it is suggested that the changes in physical properties of the films were caused by the progress of Maillard reaction. In this study, squid mantle muscle was used as an edible film-forming material. By mixing with Na-citrate, squid mantle muscle possessed the ability to form transparent films with an excellent UV barrier property. Glycerol was found to be the most effective and stable plasticizer for the films. Edible films represent an option for the utilization of discarded squid during the fishing process.