Use of the beaks and raduala by Octopus vulgaris in feeding

The role of the chitinous beaks and the radula of the cephalopod Octopus vulgaris Lamarck, when feeding on either live shore crabs or whole dead fish, has been examined. One or more of these mouthparts was removed surgically and the effect on the quantity of food eaten and the method of cleaning the prey followed. The condition of the digestivetract was observed at post-mortem.     

Vibrio lentus associated with diseased wild octopus (Octopus vulgaris)

Studies were undertaken to identify the bacteria involved in a disease of wild octopus (Octopus vulgaris). Signs of the disease include round hard lesions in the arms or head mantle, leading, in advanced cases, to the loss of skin and the exposure of the muscle beneath. Bacterial strains isolated from sterile organs have been evaluated taxonomically and by experimental infections. Different phenotypes and ribotypes of Vibrio lentus were identified. Experimental infection by bath challenge demonstrated that V. lentus was able to reproduce the skin lesions, colonize the internal organs and induce mortality in healthy octopuses. V. lentus was re-isolated from the skin lesions and gill heart of dead octopuses, as confirmed by numerical taxonomy analysis. No effects were produced in sea bream or turbot by intraperitoneal injection of the bacterial isolate.     

The mandibular movements of Octopus vulgaris

The movements of the isolated buccal mass of Octopus vulgaris have been investigated. The beaks undergo rhythmic cycles of activity in the absence of applied stimulation and after electrical stimulation of the inter-buccal connective. Initial opening, closing, retraction and re-opening phases of movement are described. This cycle of movements is taken to resemble those in the intact animal. Anatomical and electrical evidence identifies the superior mandibular muscle as being partly responsible for the closing and retraction phases of movement. The inferior buccal ganglion determines the sequence of these buccal movements, but modification by sensory feed-back from the musculature is also implied. The preparation will allow a closer comparison of the control of movement in cephalopods and gastropods.     

Monooxygenase activity of Octopus vulgaris hemocyanin

Octopus vulgaris hemocyanin ( Ov-Hc) and one of its minimal functional units ( Ov-g) have been purified, and their spectroscopic features and monooxygenase (phenolase) activity have been examined in detail. The oxy forms of both Ov-Hc and Ov-g are stable in 0.5 M borate buffer (pH 9.0) even in the presence of a high concentration of urea at 25 degrees C; approximately 90 and approximately 75% of the (mu-eta (2):eta (2)-peroxo)dicopper(II) species of Ov-Hc and Ov-g, respectively, remained unchanged after argon (Ar) gas flushing of the sample solutions for 1 h. The catalytic activity of Ov-g in the oxygenation reaction (multiturnover reaction) of 4-methylphenol ( p-cresol) to 4-methyl-1,2-dihydroxybenzene (4-methylcatechol) was higher than that of Ov-Hc, and its catalytic activity was further accelerated by the addition of urea. Kinetic deuterium isotope effect analysis and Hammett analysis using a series of phenol derivatives under anaerobic conditions (single-turnover reaction) have indicated that the monooxygenation reaction of phenols to catechols by the peroxo species of oxyhemocyanin proceeds via electrophilic aromatic substitution mechanism as in the case of tyrosinase. The effect of urea on the redox functions of oxyhemocyanin is discussed on the basis of the spectroscopic analysis and reactivity studies.     

Beak and radula growth in Octopus vulgaris

The dry weight and the crest length of the upper and lower beak, the length of the radula ribbon, the average width of the base of the six proximal and distal rachidian teeth as well as the total number of these teeth have all been related to the live body weight of octopuses between 1.1 and 4440 g. From any one of these parameters it is possible to estimate the size and approximate age of the animal.     

Nucleoside phosphorylase activity of Octopus vulgaris hepatopancreas

From a research on partially purified extracts of Octopus vulgaris hepatopancreas a number of properties of the nucleosidase present in such extracts have been defined, such as enzyme affinity towards different purine and pyrimidine ribo- and deoxyribo-nucleosides. The phosphorolytic mechanism of action of the Octopus enzyme system is similar to the mechanism already known for many nucleosidases from animal tissues. The possibility is envisaged of two different nucleosidases being present, one specific for ribonucleosides, with an acid optimum pH, and the other one for deoxyribonucleosides, with an alkaline pH optimum. Adenosine deaminase also appears to be a component of Octopus hepatopancreas.     

The Morphology and Adhesion Mechanism of Octopus vulgaris Suckers

The octopus sucker represents a fascinating natural system performing adhesion on different terrains and substrates. Octopuses use suckers to anchor the body to the substrate or to grasp, investigate and manipulate objects, just to mention a few of their functions. Our study focuses on the morphology and adhesion mechanism of suckers in Octopus vulgaris. We use three different techniques (MRI, ultrasonography, and histology) and a 3D reconstruction approach to contribute knowledge on both morphology and functionality of the sucker structure in O. vulgaris. The results of our investigation are two-fold. First, we observe some morphological differences with respect to the octopus species previously studied (i.e., Octopus joubini, Octopus maya, Octopus bimaculoides/bimaculatus and Eledone cirrosa). In particular, in O. vulgaris the acetabular chamber, that is a hollow spherical cavity in other octopuses, shows an ellipsoidal cavity which roof has an important protuberance with surface roughness. Second, based on our findings, we propose a hypothesis on the sucker adhesion mechanism in O. vulgaris. We hypothesize that the process of continuous adhesion is achieved by sealing the orifice between acetabulum and infundibulum portions via the acetabular protuberance. We suggest this to take place while the infundibular part achieves a completely flat shape; and, by sustaining adhesion through preservation of sucker configuration. In vivo ultrasonographic recordings support our proposed adhesion model by showing the sucker in action. Such an underlying physical mechanism offers innovative potential cues for developing bioinspired artificial adhesion systems. Furthermore, we think that it could possibly represent a useful approach in order to investigate any potential difference in the ecology and in the performance of adhesion by different species.     

Some Aspects of Hole-Boring Predation by Octopus vulgaris

Octopus vulgaris prey upon many gastropod species by boringholes in the shell, weakening the prey with a venom, removingthe entire prey, and eating it. When offered Strombus raninusthe Octopus quickly grasped the conch with one or a few arms,checked for occupancy by inserting an arm tip into the aperture,and passed the shell under the web to the mouth. The shell washeld against the buccal mass by the circumoral suckers and raspedrepeatedly with the radula, repositioned, and rasped again.There were brief pauses of apparent inactivity between the periodsof active rasping. The shell was penetrated at an approximatemaximal rate of 1.25 mm per hour. The boreholes averaged 0.93mm in outer diameter, 0.47 mm in inner diameter and 0.88 mmin depth. The boreholes were extremely variable in shape, size,and position on the spire. There was a marked preference forindividual animals to bore in a particular sector of the spire.Apparently the animals orient the shells by using the lip asa point of reference because lipless shells had the boreholesrandomly distributed around the shell.     

On leucophores and the chromatic unit of Octopus vulgaris

The leucophores of Octopus vulgaris are much branched cells bearing, all over the surface, small clubs that contain electron-dense material of an unknown nature. Some tens of leucophores are organized to form a "sponge" in the centre of the chromatic unit, which can be elevated above the peripheral region. This central region reflects light over a broad band and may be important in camouflage.
The chromatic unit also contains iridophores and chromatophores. The latter may be yellow, orange, red or black, and the different types are interspersed among one another in a regular manner. The chromatophores are disposed in a precise way with respect to the leucophores, the black ones lying above holes in the sponge. The possible significance of this arrangement for camouflage is discussed.     

Rapid differentiation between Octopus vulgaris Cuvier (1797) and Octopus mimus Gould (1852), using randomly amplified polymorphic DNA

Seventeen specimens of Octopus vulgaris and Octopus mimus were investigated using randomly amplified polymorphic DNA (RAPD). Clearly differentiable RAPD fingerprints allowed a fast and reliable genotypic discrimination of these species. Thus, molecular genetic evidence from total DNA complements recent results of a comparative analysis of mitochondrial sequence data supporting the taxonomic separation of Octopus mimus and Octopus vulgaris .     

Monoamine oxidase activity in hepatopancreas of Octopus vulgaris

1. Monoamine oxidase activity has been studied in hepatopancreas of Octopus vulgaris using 5-HT and PEA as substrates.2. Time courses of MAO activity against 5-HT and PEA show that the enzyme has higher affinity for PEA than for 5-HT.3. MAO activity against 5-HT appears more sensitive than MAO activity against PEA, to variations of the temperature (range 17–67°C).4. The inhibition curves obtained with clorgyline and deprenyl indicate that MAO activity is due to a single form of the enzyme, not corresponding to type A and type B MAO.5. Semicarbazide 10⁻⁴ M does not affect the deamination of 5-HT and PEA, demonstrating that a semicarbazide-sensitive amine oxidase is not involved in this process.     

Aminergic innervation of the blood vessels of Octopus vulgaris

Evidence is presented from fluorescence histochemistry studies that blood vessels in the viscera of octopus vulgaris are innervated by nerve fibres containing catecholamines. This, with other evidence, suggests that cephalopods, like vertebrates, may be capable of regulating their peripheral vasculature by central neural control.