Octopus Vulgaris Research Articles

Putative Antimicrobial Peptides of the Posterior Salivary Glands from the Cephalopod Octopus vulgaris Revealed by Exploring a Composite Protein Database.

Cephalopods, successful predators, can use a mixture of substances to subdue their prey, becoming interesting sources of bioactive compounds. In addition to neurotoxins and enzymes, the presence of antimicrobial compounds has been reported. Recently, the transcriptome and the whole proteome of the Octopus vulgaris salivary apparatus were released, but the role of some compounds—e.g., histones, antimicrobial peptides (AMPs), and toxins—remains unclear. Herein, we profiled the proteome of the posterior salivary glands (PSGs) of O. vulgaris using two sample preparation protocols combined with a shotgun-proteomics approach. Protein identification was performed against a composite database comprising data from the UniProtKB, all transcriptomes available from the cephalopods’ PSGs, and a comprehensive non-redundant AMPs database. Out of the 10,075 proteins clustered in 1868 protein groups, 90 clusters corresponded to venom protein toxin families. Additionally, we detected putative AMPs clustered with histones previously found as abundant proteins in the saliva of O. vulgaris. Some of these histones, such as H2A and H2B, are involved in systemic inflammatory responses and their antimicrobial effects have been demonstrated. These results not only confirm the production of enzymes and toxins by the O. vulgaris PSGs but also suggest their involvement in the first line of defense against microbes.

The Pupillary Response of the Common Octopus (Octopus vulgaris).

Cephalopods have very conspicuous eyes that are often compared to fish eyes. However, in contrast to many fish, the eyes of cephalopods possess mobile pupils. To increase the knowledge of pupillary and thus visual function in cephalopods, the dynamics of the pupil of one of the model species among cephalopods, the common octopus (Octopus vulgaris), was determined in this study. We measured pupillary area as a function of ambient luminance to document the light and dark reaction of the octopus eye. The results show that weak light (<1 cd/m2) is enough to cause a pupil constriction in octopus, and that the pupil reacts fast to changing light conditions. The t50-value defined as the time required for achieving half-maximum constriction ranged from 0.45 to 1.29 s and maximal constriction from 10 to 20% of the fully dilated pupil area, depending on the experimental condition. Axial light had a stronger influence on pupil shape than light from above, which hints at a shadow effect of the horizontal slit pupil. We observed substantial variation of the pupil area under all light conditions indicating that light-independent factors such as arousal or the need to camouflage the eye affect pupil dilation/constriction. In conclusion, the documentation of pupil dynamics provides evidence that the pupil of octopus is adapted to low ambient light levels. Nevertheless it can quickly adapt to and thus function under brighter illumination and in a very inhomogeneous light environment, an ability mediated by the dynamic pupil in combination with previously described additional processes of light/dark adaptation in octopus.

Bipedal locomotion by Octopus vulgaris

Bipedal locomotion by Octopus vulgaris

Evaluation of reproductive performances of the common octopus (Octopus vulgaris) reared in water recirculation systems and fed different diets

The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p < 0.05) higher (3.0 ± 0.29%) than the F group (2.16 ± 0.67%). SGR in C group was significantly higher (1.43 ± 0.12%) than the F group (1.18 ± 0.25%). Egg clusters, number of clusters, number of clusters/kg BW, and total length were more favorable in the C group than the F group. The number of clusters/kg BW of C females was 2.5 times higher than that of F females (78.1 ± 6.5 vs 31.1 ± 13.3). The total eggs number, number of eggs/cm, number of eggs/kg BW in the C group were significantly (p < 0.05) higher compared with the F group; the number of eggs/kg BW and paralarvae/kg BW were 5 times higher in the C group (115,928 ± 12,513 C vs 22,109 ± 7912 F and 114,953 ± 12,591 vs 20,729 ± 7104, respectively). Hatching rate of the C group was significantly (p < 0.05) higher compared to the F group.

Identification of octopus peptide and its promotion of β-casein synthesis in a mouse mammary epithelial cell line.

Octopus protein hydrolysate has been reported to increase milk yield and milk protein production. In this paper, the utilization and underlying mechanisms of bioactive peptide fractions from octopus protein hydrolysate on β-casein expression in mouse mammary epithelial cells (HC11) were investigated. Fraction OPH3-1 significantly stimulated cell proliferation and β-casein synthesis in HC11 cells, which was purified by ultra-filtration and gel-filtration chromatography. The MWs of the peptides from OPH3-1 ranged from 525-2,578Da and consisted of 7-26 amino acid residues. Most of the peptides demonstrated the typical characteristics of milk protein synthesis promotion, especially MGLAGPR, MGDVLNF, EAPLMHV, and TEAPLMHV. Additionally, the mRNA abundances of mTOR, S6K1, 4EBP1, JAK2, and STAT5 were significantly enhanced by OPH3-1, which was consistent with the increased β-casein expression. These results suggest that the OPH3-1 peptides can promote the proliferation of mammary epithelial cells and increase β-casein synthesis. PRACTICAL APPLICATIONS: Breastfeeding mothers are generally recommended to take octopus soup as a daily diet to promote lactation. The peptides fraction OPH3-1 from the enzymatic hydrolysate of Octopus vulgaris which was revealed to significantly stimulate mammary epithelial cell proliferation and β-casein synthesis was obtained. This study suggests that octopus peptides can be used as nutritional supplements to increase the quantity and quality of milk production.

Ahtapotun (Octopus vulgaris) metal düzeylerinin değerlendirilmesi: sağlık riskleri tahmini

The levels of 13 different metals (Mg, P, K, Fe, Cu, Zn, Mn, Se, Al, Cr, As, Cd and Pb) in mantle and arm tissues of Octopus vulgaris species, which were caught from Mersin Bay in winter, spring and summer seasons, were determined. The results were compared between the tissues and seasons. Potential health risks of consumption of common octopus, which is an economically important species, were evaluated with the possibility that adult and child consumers will consume common octopus 1, 3 or 5 days a week. In this context, Estimated Weekly Intake Level (EWI), non-carcinogenic Target Hazard Quotient (THQ) and Lifetime Carcinogenic Risk (CR) were determined. Pb level was found to be above the limit level determined by FAO, EU and Turkish Food Codex. EWI values were found to be below the PTWI values determined by EFSA and FAO / WHO. THQ and ∑THQ values, which are indicative of non-cancer health risks for consumers, were determined as &lt;1. In terms of carcinogenic risk, it was determined that these values (&gt; 10-5) for As, Cr and Cd elements pose a carcinogenic risk to the consumer, but Pb values do not pose a risk.

Use of Peripheral Sensory Information for Central Nervous Control of Arm Movement by Octopus vulgaris

Octopuses are active predators with highly flexible bodies and rich behavioral repertoires [1-3]. They display advanced cognitive abilities, and the size of their large nervous system rivals that of many mammals. However, only one third of the neurons constitute the CNS, while the rest are located in an elaborate PNS, including eight arms, each containing myriad sensory receptors of various modalities [2-4]. This led early workers to question the extent to which the CNS is privy to non-visual sensory input from the periphery and to suggest that it has limited capacity to finely control arm movement [3-5]. This conclusion seemed reasonable considering the size of the PNS and the results of early behavioral tests [3, 6-8]. We recently demonstrated that octopuses use visual information to control goal-directed complex single arm movements [9]. However, that study did not establish whether animals use information from the arm itself [9-12]. We here report on development of two-choice, single-arm mazes that test the ability of octopuses to perform operant learning tasks that mimic normal tactile exploration behavior and require the non-peripheral neural circuitry to use focal sensory information originating in single arms [1, 10]. We show that the CNS of the octopus uses peripheral information about arm motion as well as tactile input to accomplish learning tasks that entail directed control of movement. We conclude that although octopus arms have a great capacity to act independently, they are also subject to central control, allowing well-organized, purposeful behavior of the organism as a whole.

Effects of feeding with different live preys on the lipid composition, growth and survival ofOctopus vulgarisparalarvae

Effects of feeding with different live preys on the lipid composition, growth and survival of<i>Octopus vulgaris</i>paralarvae

Chromosome-level genome assembly of the East Asian common octopus (Octopus sinensis) using PacBio sequencing and Hi-C technology.

The Cephalopoda are a group of highly diverse marine species in the phylum Mollusca, which are distributed worldwide. They have evolved some vertebrate-like biological traits and exhibit complicated behavioural repertoires. Thus, they are interesting species for studying the mechanisms of evolutionary convergence, innovational functional structures and evolutionary adaptation to a highly active, predatory lifestyle in diverse marine environments. Despite the evolutionary placement and biological significance of cephalopods, genomic data on these organisms remain limited. Here, we assembled a chromosome-level genome of a female East Asian common octopus (Octopus sinensis) by combining Pacific Bioscience (PacBio) single-molecule real-time sequencing, Illumina paired-end sequencing and Hi-C technology. An O.sinensis genome of 2.72Gb was assembled from a total of 245.01Gb high-quality PacBio sequences. The assembled genome represents 80.2% completeness (BUSCO) with a contig N50 of 490.36Kb and a scaffold N50 of 105.89Mb, showing a considerable improvement compared with other sequenced cephalopod genomes. Hi-C scaffolding of the genome resulted in the construction of 30 pseudochromosomes in Cephalopoda, representing 96.41% of the assembled sequences. The genome contained 42.26% repeat sequences and 5,245 noncoding RNAs. A total of 31,676 protein-coding genes were predicted, of which 82.73% were functionally annotated. The comparative genomic analysis identified 17,020 orthologous gene families, including 819 unique gene families and 629 expanded gene families. This genomic information will be an important molecular resource for further investigation of biological function and evolutionary adaptations in octopuses, and facilitate research into their population genetics and comparative evolution.

Effects of temperature on the rate of embryonic development of cephalopods in the light of thermal time applied to aquaculture

AbstractThe temporal description of the embryonic development in ectothermic animals and the speed of development depends on environmental temperature. The concept of thermal time helps in solving this problem by making it possible to define a linear model of development linking developmental rate and temperature. The model has been scarcely applied to cephalopods in spite of being useful for programming embryonic development and hatching events. The potential application of the linear model of development would have particular interest in the case of emerging species for aquaculture such as Octopus vulgaris or Sepia officinalis. Therefore, the main goal of this work is to review the effect of temperature on the rate of embryonic development in cephalopods in relation to the linear model of development and to discuss its potential applications and limitations to cephalopod aquaculture. As a result, a good fitting of the model has been proven not only for the total time of development, but also for the time of the organogenesis phase, in nine species of cephalopods. Usually, threshold temperatures for different developmental phases, pre‐organogenesis, organogenesis and growth, are the same. In addition, the potential use of anisothermic protocols for egg incubation, as well as the problems connected with the asynchronicity of egg laying within a single spawning are also discussed. In consequence, the linear model of development seems to be useful for basic and applied research on cephalopod embryonic development and particularly for the advancement of cephalopod aquaculture.

Selection of Histological Parameters for the Development of an Analytical Method for Discriminating Fresh and Frozen/Thawed Common Octopus (Octopus vulgaris) and Preventing Frauds along the Seafood Chain

This study aimed at selecting effective histological indicators of the freezing process, for the discrimination of fresh and frozen common octopus Octopus vulgaris. Histological indices of freezing process were selected in mantle and arm muscle and axial nerve tissues. Seven histological parameters were chosen: overall muscle tissue structural organization (a); gaping among muscle bundles (b); presence of optically empty spaces between and within muscle bundles (c); white spaces percentage between and within muscle bundles (d); overall nerve structural organization (e); presence of linear fissures and/or empty spaces within neuropil and axonal tract (f); presence of empty spaces within connective tissue matrix surrounding the nerve (g); empty space percentage within arm axial nerve region (h). The parameters were assessed on 150 mantle muscle sections (a, b, c, d), 150 arm muscle (b, c) and nervous (e, f, g, h) tissue sections belonging to 20 fresh exemplars further subdued to conventional freezing procedure at − 20 °C, 25 fresh curled exemplars, 25 exemplars industrially frozen at − 80 °C, and 20 thawed, curled, and individually quick frozen exemplars. Overall structural organization (a, e), gaping (b), and presence of optically empty spaces (c, f) confirmed significant morphological freezing indices in mantle and arm sections. In mantle, two d values (d < 25% and 25% < d < 33%) were proposed as complementary thresholds to be applied in association with b and c indices for freezing discrimination. These parameters appear eligible to set a method for discriminating fresh/thawed octopus products to be applied both in official control and self-check activities.

Cognitive Stimulation Induces Differential Gene Expression in Octopus vulgaris: The Key Role of Protocadherins.

Octopuses are unique invertebrates, with sophisticated and flexible behaviors controlled by a high degree of brain plasticity, learning, and memory. Moreover, in Octopus vulgaris, it has been demonstrated that animals housed in an enriched environment show adult neurogenesis in specific brain areas. Firstly, we evaluated the optimal acclimatization period needed for an O. vulgaris before starting a cognitive stimulation experiment. Subsequently, we analyzed differential gene expression in specific brain areas in adult animals kept in tested (enriched environment), wild (naturally enriched environment), and control conditions (unenriched environment). We selected and sequenced three protocadherin genes (PCDHs) involved in the development and maintenance of the nervous system; three Pax genes that control cell specification and tissue differentiation; the Elav gene, an earliest marker for neural cells; and the Zic1 gene, involved in early neural formation in the brain. In this paper, we evaluated gene expression levels in O. vulgaris under different cognitive stimulations. Our data shows that Oct-PCDHs genes are upregulated in the learning and lower motor centers in the brain of both tested and wild animals (higher in the latter). Combining these results with our previous studies on O. vulgaris neurogenesis, we proposed that PCDH genes may be involved in adult neurogenesis processes, and related with their cognitive abilities.

Octopus americanus: a cryptic species of the O. vulgaris species complex redescribed from the Caribbean

The common octopus Octopus vulgaris Cuvier, 1797, once considered a cosmopolitan species, is a species complex composed by six species: O. tetricus, O. cf tetricus and O. sinensis in the Pacific; type I and II, in the West Atlantic; and type III in the Indian Ocean around South Africa. The tropical western central Atlantic is an important octopus fishing ground targeting O. maya, O. insularis, and a cryptic species considered to be O. vulgaris type I. In order to clarify the identification of this octopod, phylogenetic analyses were carried out with mitochondrial (COI and 16S) and nuclear (rhodopsin) genes, together with morphological analyses of 16 specimens caught in the northeastern continental shelf of Yucatan (Mexico). The main morphological traits differing from O. vulgaris were the presence, position and size of enlarged suckers and hectocotylus sucker number in males. Genetic distances and haplotype networks of the species complex were estimated using 285 COI sequences of nine Octopus species from 14 different locations around the world. The octopod sequences from Yucatan clustered within a monophyletic group that included sequences of O. vulgaris type II for the three genes analyzed. Phylogenetic distances with other members of the complex ranged between 2.71 and 3.89% using COI data. These genetic results support the presence of Octopus americanus Monfort, 1802 (formerly known as O. vulgaris type II) along the Yucatan continental shelf, a new octopod extending from the north of Argentina to the northwest coast of the USA.

Evidence of Sleep Cycle Analogous to Vertebrate SWS/REM Alternation in the Octopus

The combination of body quiescence and skin pattern changes displayed periodically by Sepia officinalis, as well as the high threshold for arousal upon stimulation and increased brain activity in quiescent Octopus vulgaris, suggest the existence of a state akin to rapid-eye-movement sleep (REM) in cephalopods. Would be possible that cephalopods, as amniotes, sleep through the alternation of distinct quiescent states, analogous to slow-wave sleep (SWS) and REM? To investigate this possibility, we video-recorded 4 adult specimens of Octopus insularis and quantified in detail their behavioral states and transitions. We also performed sensory stimulation to measure reaction times across all behavioral states. Two distinct quiescent states occurred in tandem, both quite unresponsive to stimulation (median reaction time: 50 s). The first state was SWS-like, characterized by uniformly pale skin, closed pupils, and long episode durations (median 415.2 s). The second state was REM-like, characterized by dynamic skin patterns, rapid eye movements and short episode durations (median 40.8 s). The REM-like state was periodic (60% of all recurrences between 26.85-39.15 min) and occurred mostly after the SWS-like state (82% of all transitions). These observations support the existence in cephalopods of an ultradian sleep cycle analogous to the SWS/REM alternation.

Evidence of price premium for MSC-certified products at fishers’ level: The case of the artisanal fleet of common octopus from Asturias (Spain)

Eco-labelling is gaining great international importance as a way to promote sustainable fisheries driven by the increasing demand for eco-certified products. Since 2016, the artisanal fleet to fish common octopus (Octopus vulgaris) of Navia-Porcía (Asturias, Spain) is certified by the Marine Stewardship Council (MSC), being the first octopus fishery certified by MSC in the world. Even though there is an ample evidence that confirms the existence of price premiums for seafood products with eco-labels in the retail market, there is still little research demonstrating the existence and the extent of price premiums at the producer or fisher's level, specifically from small-scale or artisanal fleets. The aim of this research is, therefore, to test the existence of a price premium for the artisanal fishers of MSC-certified common octopus from Asturias as well as to estimate the value of this premium. To carry out this analysis, we have applied the difference-in-difference (DiD) method using a panel of prices and quantities of common octopus sold at ports of the Spanish region of Asturias from 2010 to 2019. Our results confirm the existence of a price premium, between a 15.2% and a 24.6% over the uncertified octopus' price, that is paid to Asturian fishers who fish and sell the MSC-certified product. Thus, this paper provides evidence about the economic benefits of environmental certifications for small-scale and artisanal fleets to compensate the certification costs and promote sustainable fishing practices.

Biochemical Composition and Energy Strategy Along the Reproductive Cycle of Female Octopus vulgaris in Galician Waters (NW Spain)

The common octopus, Octopus vulgaris, has a short life cycle, growing rapidly to maturity, spawning once, and characterized by an asynchronic oocyte development and a synchronic ovulation dying after breeding. This species has a protein and amino acid metabolism and it is usually defined as an income breeder. However, most biochemical studies lack an examination of the whole reproductive cycle, in particular the spawning process. We here studied the biochemical changes and determined the energy strategy along reproduction in female O. vulgaris, and found that proteins were the main energy reserve, primarily located in the body muscle when sexually maturing and decreasing during breeding. Lipids were also an important source of energy in the ovary and digestive gland and decreased during breeding too. By contrast, glycogen had a minor contribution to the energy content and was the unique compound that increased in spawning and post-spawning females. Additionally, the most abundant fatty acids (FA) in all tissues were 16:0, 18:0, 20:1n9, 20:4n6 (ARA), 20:5n3 (EPA) and 22:6n3 (DHA), with a clear predominance of long-chain polyunsaturated FA. The FA profile of mature ovaries was compared with other life stages finding similitudes with eggs, hatchlings and juveniles but considerable differences with paralarvae which showed higher DHA/ARA and EPA/ARA ratios. Therefore, we found important biochemical changes along the reproductive cycle that determined the energetic signature in each tissue, though no significant energy trade-offs between tissues were found, suggesting that, on the one hand, female O. vulgaris obtained energy directly from food accumulated simultaneously in the somatic and reproductive tissues during sexual maturation. However, an energy reallocation from somatic to reproductive growth would occur once vitellogenesis has started, so that the rate at which body growths would decrease in favor of ovary growth. On the other hand, during breeding, a general decrease in the energy content occurred in all tissues, so that the ovary would be responsible for the spawning success, whereas muscle tissues and digestive gland would independently supply the energy needed for the body maintenance safeguarding the female survival needed for the maternal care.

Longline métiers and associated economic profiles in eastern Mediterranean fisheries: The case study of Kalymnos Island (South Aegean Sea)

The small-scale fishery has a high socio-economic importance in the Mediterranean Sea. This is especially relevant for specific areas that harbor, proportionally, very large part of the fleet, and thus, represent hot spots. Among such areas, Kalymnos Island merits special attention as it harbors the largest and most active small-scale fleet in the eastern Mediterranean. Therefore, the present study analyzes the small-scale longline fishery in Kalymnos, using the métiers approach, to assess its dynamics and evaluate associated economic profiles. A multivariate analysis was used to identify the relevant métiers, by inputting the main resources and fishing gear data that were recorded during landings. Six main practices were observed using set longlines, drifting longlines, handlines and squid jig-lines as fishing gears, and targeting the species Pagrus pagrus, Diplodus vulgaris, Pagellus erythrinus, Sparus aurata, Xiphias gladius, Octopus vulgaris and Loligo vulgaris; the above métiers earned a profit margin. The study revealed the multi-species nature of longline fishery in Kalymnos, and provided baseline information for their associated economic profiles, towards the development and implementation of sustainable management plans.

Ontogenic change in the vertical swimming of East Asian common octopus Octopus sinensis paralarvae under different water flow conditions

The East Asian common octopus Octopus sinensis is a bottom-dwelling species, but goes through a planktonic phase as ‘paralarvae’ during the first several weeks of life. As the swimming performance of the paralarvae is relatively poor, their dispersion relies primarily on ocean currents; however, vertical swimming may play an important role in their horizontal dispersion by controlling their buoyancy in the current. Within this context, ontogenic changes in vertical swimming in relation to the ambient water flow are key to understanding the dispersion properties of the paralarvae and the subsequent onset of settlement, yet this information remains largely unknown. Here, we investigated the effects of different water flows (downward × 4 velocities, stagnant and upward × 5 velocities) on the vertical swimming position in test columns using laboratory-raised O. sinensis paralarvae aged 0, 5, 10 and 15 days during the day and at night. Paralarvae younger than 10 days ( 5 mg) commenced short clinging behaviour, and their swimming positions dispersed downwards during daytime regardless of the water flow, indicating the onset of the transition to settlement. In contrast, their position shifted to near the upper limit at night by swimming upwards, even under downward water flows. Our results suggest that O. sinensis exhibits characteristic behaviour that alternates between diurnal descent dispersion with clinging (hyperbenthic trait) and nocturnal upward swimming (planktonic trait) during the transition to permanent benthic life.

Molecular Identification, Characterization, and Expression Analysis of a Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Pacific Abalone, Haliotis discus hannai.

A full-length cDNA sequence encoding a GnRH receptor was cloned from the pleuropedal ganglion of the Pacific abalone, Haliotis discus hannai. The cloned sequence is 1499-bp in length encoding a protein of 460 amino acid residues, with a molecular mass of 52.22 kDa and an isoelectric point (pI) of 9.57. The architecture of HdhGnRH-R gene exhibited key features of G protein-coupled receptors (GPCRs), including seven membrane spanning domains, putative N-linked glycosylation motifs, and phosphorylation sites of serine and threonine residues. It shared 63%, 52%, and 30% sequence identities with Octopus vulgaris, Limulus polyphemus, and Mizuhopecten yessoensis GnRH-R II sequences, respectively. Phylogenetic analysis indicated that HdhGnRH-R gene was clustered with GnRH-R II of O. vulgaris and O. bimaculoides. qPCR assay demonstrated that the mRNA expression level of this receptor was significantly higher in the pleuropedal ganglion than that in any other examined tissue. Transcriptional activities of this gene in gonadal tissues were significantly higher in the ripening stage. The mRNA expression of this gene was significantly higher in pleuropedal ganglion, testis, and ovary at higher effective accumulative temperature (1000 °C). In situ hybridization revealed that HdhGnRH-R mRNA was expressed in neurosecretory cells of pleuropedal ganglion. Our results suggest that HdhGnRH-R gene synthesized in the neural ganglia might be involved in the control of gonadal maturation and gametogenesis of H. discus hannai. This is the first report of GnRH-R in H. discus hannai and the results may contribute to further studies of GPCRs evolution or may useful for the development of aquaculture method of this abalone species.

Variation in Catch Size and Changes in Reproductive Biology of Common Octopus Octopus vulgaris in the Coastal Waters Off Gyeongnam, Korea

Variation in Catch Size and Changes in Reproductive Biology of Common Octopus Octopus vulgaris in the Coastal Waters Off Gyeongnam, Korea