Giant Squid Research Articles

Gradually Crosslinking Carbon Nanotube Array in Mimicking the Beak of Giant Squid for Compression‐Sensing Supercapacitor

AbstractPortable and wearable electronics are undergoing rapid development, but these flexible devices may break and fail to work under high compressive strains. Here, presented is a new free‐standing compressible carbon nanotube array (CCNA) with a unique gradually crosslinking structure, which mimics the gradient structure of the beak of the giant squid. The CCNAs can tolerate various compressive strains and demonstrate high reversible compressibility up to 1 00 000 cycles with high electrical conductivities. On the basis of the CCNA, a novel all‐solid‐state compression‐sensing supercapacitor (CSS) that can store energy and tolerate and sense the external strain change is produced. It demonstrates a high capacitance of 93.2 mF cm−2 and can be maintained by 94% even after 3000 continuous compressing cycles at a strain of 60%. In addition, it also shows superior strain sensing capability and stability up to 1900 compressive cycles. These flexible CSSs promise a wide range of applications including electronic skins and advanced bioelectronic devices.

Effect of temperature on the actomyosin-paramyosin structure from giant squid mantle (Dosidicus gigas).

The secondary structure of a protein determines its functional properties, such as its gelling capacity. The α-helix and β-sheet comprise its main structures. Myofibrillar proteins from jumbo squid are composed mainly of the actomyosin-paramyosin complex; this complex contains a high percentage of α-helix, because actin, paramyosin, and myosin constitute 30%, 100%, and 55% of the α-helix, respectively. It is important to elucidate the role of the secondary structures in the gelation of giant squid proteins as they form gel. The role of the secondary structures in the gelation of giant squid proteins is therefore very important. For this reason, the objective of this work was to evaluate the effect of temperature on the structural behavior of actomyosin-paramyosin isolate (API) from Dosidicus gigas. The unfolding of the API system, which is composed of the actomyosin-paramyosin complex, was clarified by studying surface hydrophobicity and viscosity. Three characteristic peaks were found, associated with myosin, paramyosin, and actin. Infrared and circular dichroism corroborated the view that API undergoes major structural changes, because it proceeds from mostly an α-helix structure to 100% β-sheet. The structural rearrangement favors gelation by cross-linking, generating new protein-protein and water-protein interactions, which create a more stable structure compared to mantle proteins (MP). Likewise, the presence of sarcoplasmic and stromal proteins in D. gigas muscle prevents the unfolding of myofibrillar proteins, favoring gelation by agglomeration, decreasing the ability to trap water and thus its gelling capacity. © 2019 Society of Chemical Industry.

Carboxymethyl cellulose films containing nanoliposomes loaded with an angiotensin-converting enzyme inhibitory collagen hydrolysate

A collagen hydrolysate (HC) obtained from giant squid (Dosidicus gigas) tunics was encapsulated in soy phosphatidylcholine liposomes in the presence and absence of glycerol. The z-average and ζ-potential of empty and loaded liposomes ranged from 92.4 to 96.0 nm and from −30.4 to −34.5 mV, respectively. The HC was encapsulated with an entrapment efficiency of 80–83%, and the resulting liposomal dispersions showed ≈50% of angiotensin-converting enzyme (ACE) inhibitory capacity. An in vitro process of gastrointestinal digestion of the liposomes increased the antihypertensive potential, regardless of the presence or absence of glycerol. The liposomal dispersions were incorporated into carboxymethyl cellulose films, in which two ways of adding glycerol were compared: adding it directly to the film-forming dispersion or incorporating it previously into the liposomes. The presence of intact liposomes in the films, which was corroborated by transmission electronic microscopy at cryogenic temperature, decreased the water solubility and increased adhesiveness. The results demonstrated that glycerol-containing liposomes were less affected by the film drying step and also the subsequent simulated gastrointestinal digestion, with greater preservation of vesicle size and morphology, than if glycerol was added directly to the film-forming solution.

Starch/chitosan/glycerol films produced from low-value biomass: effect of starch source and weight ratio on film properties

Films based on chitosan from giant squid (Dosidicus gigas) residual endoskeleton, starch from different low-value agroindustrial byproducts and glycerol were successfully obtained. Four starch sources and three different weight ratios (1/1, 2/1 and 5/1 of starch/chitosan) were used. Applying a statistical design of completely randomized blocks, the effect of starch source and weight ratio on the film properties were evaluated. The starch source did not affect any of the tested properties. However, film properties such as thickness, water solubility, water vapor permeability, elongation, and tensile strength revealed significant differences (p<0.01) related to the starch weight ratio in the films. A higher starch weight ratio led to lower water solubility; nevertheless, the higher starch weight ratio led to films with higher thickness, water vapor permeability and tensile strength.

Whale rover moving along the surface of sperm whale

ABSTRACTBiologging, which uses small data loggers directly attached to the bodies of animals to collect various behavioral data, can be an effective means for revealing the mysteries of animal life. With respect to marine animals, zoologists have attempted to obtain video data of a sperm whale eating a giant squid using biologging. These previous efforts have been unsuccessful because the biologger, which was attached to the whale's back that emerged from the sea as the whale swam, provided poor visibility of the whale's mouth area in the deep sea. To solve this problem, we proposed a novel roving biologger or whale rover that travels along a sperm whale's body surface from its back to its mouth area using robotic technology. Four prior whale rover prototypes have been designed and developed. In this study, we further improved the whale rover design to allow for adapted travel on curved or uneven surfaces. The feasibility of this fifth prototype was confirmed using both field and laboratory experiments. These experimental results demonstrated the whale rover's ability to successfully travel across a flat surface at a depth of almost 500 m and across a curved surface in a laboratory water tank.

Effect of ultrasonication time on the functional properties of giant squid (Dosidicus gigas) mantle protein concentrate

The giant squid (Dosidicus gigas) might be used as a raw material for a protein concentrate. However, it has been observed that colloidal systems formed from squid proteins have limited functionality. Therefore, several investigations have been done to improve the functional properties of squid proteins. Recently ultrasound has been considered a technology for improving the functional properties of proteins. For this reason and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of sonication time on the main functional properties of proteins. Sonication at 20 kHz and 20% amplitude were used during 0, 30, 60, and 90 s for foam and emulsion evaluations, and for 0, 1, and 3 min to evaluate gelling capacity. The emulsifying activity index was the highest at 60 s, while the emulsion stability index was the best at 90 s. Foaming capacity was significantly higher at 60 and 90 s, while the foam stability was 100% for all treatments. Finally, the water holding capacity and the texture profile analysis of gels showed an improvement.

Continuously Bursting Simulations and Analytical Solutions of the Neocortical Neurons Model

The well-known Hodgkin Huxley (HH) model employs the electrical circuit theory to describe the membrane potential of a cell in a giant squid axon. Hugh R. Wilson introduced human and mammalian neocortical neurons (HMNN) model which limits the potential nonlinearities to cubic polynomials while retains the same basic biophysics. This model has been used in neural dynamics, neural network, neural field theory, and epilepsy. Although mathematical methods have been applied to solve the HH model, a survey of recent papers reveals that HMNN model has not been solved analytically by the similar methods. In this work, a step homotopy analysis method (SHAM), an extended approach of the homotopy analysis method (HAM), is applied to solve HMNN model analytically for the first time. We present that the SHAM is an efficient method which yields high accuracy. The presented method is suitable for solving a variety of nonlinear dynamical systems.

Collections Support Services (CSS) - 25 Years of Improving Access and Care to our Nation’s Collections

Originally formed in the early 1980s as the Move Crew to move museum collections to the newly opened state of the art Smithsonian Institution’s Museum Support Center, Collections Support Services has evolved into a team of highly skilled museum professionals recognized as trusted experts, innovators, project managers, and problem solvers in all aspects of collections stewardship. We have packed, moved, and stored MILLIONS of objects across Smithsonian museums including the National Museum of Natural History and several of our art museums; the Freer Sackler Gallery, Hirshhorn Museum and Sculpture Garden, and National Museum of African Art. Our vast experience with Natural History collections has been with objects ranging from microscopic invertebrates, fragile bird eggs, 40’ war canoes, whale skulls, giant squids and EVERYTHING in between! Many of these collections came from overcrowded and dusty attics, basements, and warehouses prone to flooding, pest infestation, and poor climate control. We have spent the last 25 years moving these collections into our climate controlled storage pods furnished with new metal cabinets designed for long term preservation. Some of the unique packing and transportation methods we will highlight in this presentation are “airbags” that encompass fragile bird skeletons and uniform shipping containers made of ethafoam planks and old wooden drawers. In addition, we have designed and constructed aluminum pallets for oversized collections, specialized elephant skull pallets, and plaster jackets for paleo fossil specimens. These storage solutions have greatly improved access to collections by allowing researchers to study specimens with minimal handling necessary. This presentation will specifically demonstrate these and other dramatic improvements that we have made as well as highlight innovative solutions we developed to safely transport, store, and provide better access to our Natural History collections for future generations.

A review on the biodiversity, distribution and trophic role of cephalopods in the Arctic and Antarctic marine ecosystems under a changing ocean

Cephalopods play an important role in polar marine ecosystems. In this review, we compare the biodiversity, distribution and trophic role of cephalopods in the Arctic and in the Antarctic. Thirty-two species have been reported from the Arctic, 62 if the Pacific Subarctic is included, with only two species distributed across both these Arctic areas. In comparison, 54 species are known from the Antarctic. These polar regions share 15 families and 13 genera of cephalopods, with the giant squid Architeuthis dux the only species confirmed to occur in both the Arctic and Antarctic. Polar cephalopods prey on crustaceans, fish, and other cephalopods (including cannibalism), whereas predators include fish, other cephalopods, seabirds, seals and whales. In terms of differences between the cephalopod predators in the polar regions, more Antarctic seabird species feed on cephalopods than Arctic seabirds species, whereas more Arctic mammal species feed on cephalopods than Antarctic mammal species. Cephalopods from these regions are likely to be more influenced by climate change than those from the rest of the World: Arctic fauna is more subjected to increasing temperatures per se, with these changes leading to increased species ranges and probably abundance. Antarctic species are likely to be influenced by changes in (1) mesoscale oceanography (2) the position of oceanic fronts (3) sea ice extent, and (4) ocean acidification. Polar cephalopods may have the capacity to adapt to changes in their environment, but more studies are required on taxonomy, distribution, ocean acidification and ecology.

Effect of setting on the gelling properties of a protein concentrate from giant squid (Dosidicus gigas) mantle

Abstract Different studies on obtaining protein concentrates or surimi from giant squid ( Dosidicus gigas) have reported that soft gels are obtained in comparison with other fish species. Therefore, the aim of this research was to investigate the effect of the setting (30 and 60 °C, for 0, 30, 60, and 90 min) on the gelling capacity as a possible alternative to improve the textural characteristics of the gels. Treatments at 60 °C (G4, G5, and G6) had a higher percentage of insoluble protein, while the electrophoretic profile showed the presence of high molecular weight (HMW) aggregates, as well as the decrease of myosin, paramyosin and actin bands as the incubation time was increased. Likewise, these systems presented a lower content of total sulfhydryl (TSH), which is attributed to the formation of disulfide bridges. The texture profile analysis (TPA) showed that the setting application affected the different parameters evaluated (strength, elasticity, and cohesiveness). Setting as pretreatment did not prove to be a good alternative for the gelling of proteins from giant squid mantle, since the control treatment (no setting) was that which exhibited better textural characteristics.

Relationships between morphometrical properties and the texture of an extrusion-expanded snack made from squid mantle (Dosidicus gigas).

The giant squid is a very attractive species because its meat has low caloric intake, high protein content, and is an important source of omega 3 fatty acids. Despite the desirable qualities of the squid meat its consumption is very low due to the low diffusion of the properties of its meat, acid, and ammoniacal flavor, rigid texture that requires prolonged cooking times and lack of alternatives of consumption. In Mexico, this type of squid is mainly destined for export as frozen mantle and products with little added value, which generates little economic benefit. Therefore, the results of this research may be of interest to the squid processing industry, which demands new forms of consumption of this marine species to increase their commercialization and added value.

Spectroscopic imaging: Nuclear magnetic resonance and Raman spectrometry for the detection of collagen cross-linking from giant squid mantle, fin, and tentacle tissues

ABSTRACTThe application of proton nuclear magnetic resonance (1H-NMR) imaging and Raman spectrometry is described for the detection and structural characterization of collagen cross-linking (pyridinoline) in soluble and insoluble collagen fractions obtained by cation-exchange separation of the mantle, fins, and tentacles of giant squid (Dosidicus gigas). The pyridinoline was detected using a fluorometric procedure only in the soluble collagen fractions. However, the pyridinoline was detected using high-performance liquid chromatography (HPLC) only in the insoluble collagen fraction from the tentacles. Meanwhile, in all samples, pyridinoline was detected by 1H-NMR and Raman spectrometry. The higher peak intensities in both methods were observed in the insoluble collagen fraction from the tentacles. The muscles showed a lower decrease in shear force after 30 min of cooking. 1H-NMR and Raman spectrometry provides an assay which is more sensitive than fluorescence and HPLC for pyridinoline detection in squid tissues, suggesting greater potential for the analysis of different types of tissue and collagen fractions.

First record on stranding of a live giant squid Architeuthis dux outside Japanese waters.

First record on stranding of a live giant squid Architeuthis dux outside Japanese waters.

Mechanism Discovery and Design Explanation: Where Role Function Meets Biological Advantage Function

In the recent literature on explanation in biology, increasing attention is being paid to the connection between design explanation and mechanistic explanation, viz. the role of design principles and heuristics for mechanism discovery and mechanistic explanation. In this paper we extend the connection between design explanation and mechanism discovery by prizing apart two different types of design explanation and by elaborating novel heuristics that one specific type offers for mechanism discovery across species. We illustrate our claims in terms of two lines of biological research on the biological advantages of organismal traits, one on the eye-size of giant squid, the other on foraging habits of specific bat species. We argue that this research illustrates useful heuristics for mechanism discovery across species, viz. reasoning strategies to infer likely mechanisms for a certain biological role based on assessments of the environmental conditions in which the role is performed efficiently (i.e., offers a biological advantage) and less or in-efficiently. We bring out the novel features of our analysis in terms of a comparison with mechanistic approaches to mechanism discovery, amongst which graph-theoretical ones, and by comparing the different types of design explanation and the discovery heuristics they support.

Physicochemical characterization of actomyosin-paramyosin from giant squid mantle (Dosidicus gigas).

The giant squid (Dosidicus gigas) has been proposed as raw material to obtain myofibrillar protein concentrates. However, it has been observed that colloidal systems formed from squid proteins have limited stability. Therefore, the isolation and characterization of the actomyosin-paramyosin isolated (API) complex were performed, because they are the main proteins to which functionality has been attributed. Densitogram analysis revealed 45% of actin, 38% of myosin and 17% of paramyosin. The amino acid profile indicates a higher proportion of acidic amino acids, which gives a higher negative charge; this was supported by the zeta potential. Total sulfhydryl (TSH) content was lower compared with proteins of other aquatic species. The higher percentage of actin in relation to myosin, the presence of paramyosin, as well as the low content of sulfhydryl groups, could comprise the main causes of the low technological functional property of proteins from D. gigas mantle. © 2017 Society of Chemical Industry.

A giant squid (Architeuthis dux) off Reunion Island, western Indian Ocean: the greatest giant ever?

A freshly dead individual of the giant squidArchiteuthis dux, presumably mutilated by a predator of bigger or comparable size, is reported from the south-western Indian Ocean in proximity to Reunion Island. The species was identified from body and beak morphology and validated genetically. The dorsal mantle length (DML) estimated from beak measurements (lower rostral length, LRL) varied between 2153 and 3060 mm depending on the allometric equation used. TheArchiteuthis duxindividual described here is the biggest giant squid ever reported for the region.

Influence of freezing temperature and deacetylation degree on the performance of freeze-dried chitosan scaffolds towards cartilage tissue engineering

Chitosan-based porous structures have been significantly studied across the world as potential tissue engineering scaffolds. Despite the differences in chitosan produced from squid pens or crustacean shells, with the former being more reactive and easily available with a higher degree of deacetylation (DD), most of the studies report the use of crab or shrimp chitosan as they are readily available commercial sources. The aim of this work was to highlight the great potential of chitosan produced from squid pens for biomedical application. From freeze-dried scaffolds for soft tissue engineering, we investigated the influence of the DD of chitosan and the freezing temperature during processing on their performance. Chitosan was obtained by deacetylation of β-chitin previously isolated from endoskeleton of giant squid Dosidicus gigas (DD 91.2%) and compared with a commercially available batch obtained from crab shells (DD 76.6%). Chitosan solutions were frozen at −80°C or −196°C and further freeze-dried to obtain 3D porous structures (scaffolds). Scaffolds prepared at −196°C have a compact structure with smaller pores, while those prepared at −80°C showed a lamellar structure with larger pores. The compressive modulus varied from 0.7 up to 8.8MPa. Both types of scaffolds were stable on PBS, including in the presence of lysozyme, up to 4 weeks. Furthermore, the squid chitosan scaffolds processed at −80°C promoted ATDC5 chondrocyte-like cells adhesion and proliferation. The results suggest that the developed squid chitosan scaffolds might be further exploited for applications in cartilage tissue engineering.

Biological report of a giant deep-sea squid Onykia robusta collected from the Sanriku Coast, Japan: implications for low genetic diversity

Despite their appeal to both researchers and the general public, the biology of giant deep-sea squids remains enigmatic. The robust clubhook squid Onykia robusta (Verrill, 1876) is one of the largest living deep-sea squids. It is distributed across the northern Pacific Ocean between Japan and California, including the Bering Sea. Although this species has been frequently caught by fishermen, its biology remains largely unknown. In this paper, I report biological data from one specimen, which was collected from the Sanriku Coast of northeastern Japan. The individual was a sexually mature female (total length: 246 cm, mantle length: 125 cm, wet body weight: 26 kg) and with oocytes that may have been large enough to begin yolk accumulation. Low genetic diversity within this species was implied by comparative analysis of the mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) gene (n = 5; additional four sequences sourced from GenBank). The low nucleotide diversity (π = 0.0044) was similar to that of the deep-sea giant squid Architeuthis dux, which is known from mtDNA analysis to lack discernible population structure, showing no genetic differentiation among samples from different regions of the Pacific. Architeuthis dux has been hypothesized to be highly migratory, probably through a pelagic paralarval stage. My data suggest the presence of a common dispersal strategy among the deep-sea giant squids.

Dwarf males of giant warty squid Kondakovia longimana and a description of their spermatophores

Antarctic squids are widely known to play an important role in the diet of various Antarctic predators, although the biology of those squids and how that relates to their availability to their predators is poorly known. We assessed the reproductive system of the deep-sea giant warty Antarctic squid Kondakovia longimana under a predator–prey context. The spermatophores of male K. longimana are described, based on two specimens foraged by albatrosses at Bird Island, South Georgia (54°S, 38°W). Spermatophore length (SL) was 42–90 mm, head occupied mean = 1.8–2.4% SL, ejaculatory tube = 17–22% SL, cement body = 19–22% SL, seminal reservoir = 56–59% SL and rear empty part = 0.4–0.8% SL. All spermatophores of K. longimana in our study were normal and functional, and very dissimilar to those of other spent squid, in which the spermatophores have short, semi-transparent seminal reservoirs and a large empty rear part. Senescent male K. longimana could become available to predation by albatrosses (presumably being surfaced) with spermatophoric sacs (Needham’s sacs) containing at least a hundred of normal spermatophores having no evidence of reproductive system degeneration. From known relation between beak and body size all known adult males in K. longimana were dwarfs in respect to females. Our data also show that they have extended spermatophore production as in other squids.

Mismatch between the eye and the optic lobe in the giant squid.

Giant squids (Architeuthis) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol. 22, 683–688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information. In this study, the optic lobe of a giant squid (Architeuthis dux, male, mantle length 89 cm), which was caught by local fishermen off the northeastern coast of Taiwan, was scanned using high-resolution magnetic resonance imaging in order to examine its internal structure. It was evident that the volume ratio of the optic lobe to the eye in the giant squid is much smaller than that in the oval squid (Sepioteuthis lessoniana) and the cuttlefish (Sepia pharaonis). Furthermore, the cell density in the cortex of the optic lobe is significantly higher in the giant squid than in oval squids and cuttlefish, with the relative thickness of the cortex being much larger in Architeuthis optic lobe than in cuttlefish. This indicates that the relative size of the medulla of the optic lobe in the giant squid is disproportionally smaller compared with these two cephalopod species. This morphological study of the giant squid brain, though limited only to the optic lobe, provides the first evidence to support that the optic lobe cortex, the visual information processing area in cephalopods, is well developed in the giant squid. In comparison, the optic lobe medulla, the visuomotor integration centre in cephalopods, is much less developed in the giant squid than other species. This finding suggests that, despite the giant eye and a full-fledged cortex within the optic lobe, the brain of giant squids has not evolved proportionally in terms of performing complex tasks compared with shallow-water cephalopod species.