Self-Recognition Mechanism between Skin and Suckers Prevents Octopus Arms from Interfering with Each Other

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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.     

The oxidation of Octopus vulgaris hemocyanin by nitrogen oxides

The reaction of Octopus vulgaris hemocyanin with nitrite was studied under a variety of conditions in which the green half-met derivative is formed. Analytical evidence shows that the amount of chemically detectable nitrite in various samples of the derivative is not proportional to the cupric copper detected by EPR. The kinetics of oxidation of hemocyanin as a function of protein concentration and pH, in the presence of nitrite and ascorbate, is consistent with a scheme in which NO2 is the reactive oxidant. We suggest that the green half-methemocyanin contains a metal center with one cuprous and one cupric copper without an exogenous nitrogen oxide ligand.     

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.     

The fine structure of the retinal plexus in Octopus vulgaris

Summary The plexiform layer of the octopus retina was investigated by means of electron microscopy. The axonic processes of visual cells contain closely packed microtubules, 300 Å in diameter, running parallel to one another along the long axis of the processes. Visual cells also send out a large number of thin axon collaterals. Each of them forms presynaptic knobs with numerous clear vesicles along their course. These are assumed to be concerned with the reciprocal communication between visual cells. Nerve endings with dense-cored vesicles form synaptic contacts with visual cells. The visual cells show some spherical protrusions into the perivascular spaces.Octopuses, captured off the coast of Onagawa (Miyagi-ken, Japan) in autumn of 1963 and 1964, were offered for this research through the kindness of Dr. Kyoji Tasaki, Assistant Professor of Physiology in Tohoku University School of Medicine.I wish to thank Professor Toshiyuki Yamamoto for his encouragement and suggestions throughout all stages of this work, and also Mr. Masae Kato for his technical assistance in drawing.     

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.     

Progesterone induces activation in Octopus vulgaris spermatozoa

The purpose of the present study was to determine whether Octopus vulgaris spermatozoa are activated by progesterone stimulation. Spermatozoa were collected from the spermatophores in the Needham's sac of the male (MS) and from the spermathecae of oviducal glands of the female (FS). We used transmission (TEM) and scanning (SEM) electron microscopy to study the morphology of untreated, Ca2+ ionophore A23187 and progesterone-treated MS spermatozoa, and untreated FS spermatozoa. We showed that ionophore and progesterone stimulation of MS spermatozoa induce breakdown of the membranes overlapping the acrosomal region, exposing the spiralized acrosome. These modifications resemble the acrosome reaction observed in other species. FS stored in the spermathecae did not show the membranes covering the acrosomal region present in the MS spermatozoa. When ionophore and progesterone treatments were performed in Ca2+-free artificial sea water, no changes were observed, suggesting the role of external calcium in modifying membrane morphology. Lectin studies showed a different fluorescence distribution and membrane arrangement of FS-untreated spermatozoa with respect to the MS, suggesting that spermatozoa transferred in the female genital tract after mating, are stored in a pre-activated state. The plasma membrane of the untreated MS and FS spermatozoa was labelled with Progesterone-BSA-FITC, indicating the presence of plasma membrane progesterone receptor. Taken together these data suggest that progesterone induces an acrosome- like reaction in MS spermatozoa similar to that induced by calcium elevation. In addition progesterone may play a role in the pre-activation of spermatozoa stored in the female tract, further supporting the hypothesized parallelism between cephalopods and vertebrates.     

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.     

Zur endokrinen Steuerung der Melanophoren-Reaktion bei Octopus vulgaris

Zusammenfassung Auf Grund früherer experimenteller Untersuchungen wurde eine endokrine Funktion von Serotonin beim Ablauf vegetativ gesteuerter Vorgänge angenommen. Es wurde nachgewiesen, daß auch eine solche Funktion diesem Hormon bei der Melanophorenreaktion des Octopus vulgaris zukommt. Sie besteht in einer zellkontrahierenden Wirkung, die sich antagonistisch zu der durch Acetylcholin bewirkten Zellexpansion verhält. Adrenalin und Histamin sind ebenso wie Melanophorenhormon in genanntem Sinne unwirksam. Es wird angenommen, daß es sich bei dem aufgezeigten Mechanismus um ein physiologisches Geschehen bei der in der Funktion bisher unbekannten Farbwechselreaktion des Octopus vulgaris handelt.Mit Unterstützung der Deutschen Forschungsgemeinschaft an der Stazione Zoologica in Neapel ausgeführt.Herrn Prof. Dr. Kosswig, Direktor des Zoologischen Staatsinstitutes der Universität Hamburg, und Frau Prof. Oboussier, Zoologisches Staatsinstitut Hamburg, danken wir für Literaturhinweise und für die Ermöglichung anatomischer Studien.     

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.