Octopus Dofleini Research Articles

Common Loon, Gavia immer, feeds on Pacific Giant Octopus, Octopus dofleini

Common Loon, Gavia immer, feeds on Pacific Giant Octopus, Octopus dofleini

Exploration, play and habituation in octopuses (Octopus dofleini).

Exploration, play and habituation in octopuses (Octopus dofleini).

Exploration, play and habituation in octopuses (Octopus dofleini).

Exploration, play and habituation in octopuses (Octopus dofleini).

Intramolecular localization of the functional units of Sepia officinalis hemocyanin by immunoelectron microscopy

The quaternary structure of Sepia officinalis hemocyanin (Hc) as studied in immunoelectron microscopy with rabbit IgGs and Fab fragments raised against functional units (FU) Soc, Sod, Soe, Sof, Sog, and Soh and fragment Soab. The architecture of immunocomplexes shows that (i) epitopes characteristic of FUs Soc and Sog and of fragment Soab are located in the two external tiers of FUs, (ii) FUs Soh and Soe or Sod are located in arches. These results were confirmed using immunocomplexes made up of Sepia Hc and IgGs or Fab fragments purified from antisera raised against FUs of Octopus vulgaris and Octopus dofleini. Frozen-hydrated immunocomplexes containing one Hc molecule and at least one FU-specific Fab fragment were observed in the electron microscope and submitted to image processing. When the Hc molecule is viewed along its 5-fold axis (i) anti- Soc Fab fragments project on a radius passing through the arch’s pillar, (ii) anti- Sof Fabs project slightly out of the arches, and (iii) anti- Soh Fabs project between neighboring arches. When applied to a recent three-dimensional (3D) reconstruction volume, these results allow us to deduce the intramolecular location of five of the eight FUs. For the last three FUs limited uncertainties remain: (i) Soc can be located in two positions in the external tier of FUs; (ii) Soa and Sob can both occupy three positions in the external tiers; and (iii) because of an immunological cross-reactivity Sod may be located in the wall and Soe in the arch, or vice versa. An analysis of the quaternary structure considering the possible locations of the 80 FUs and postulating a single type of subunit shows that 80 possibilities of paths still exist for the polypeptide chain. To solve definitely these 80 possibilities only five questions remain to be answered.

Sequence of the Octopus dofleini hemocyanin subunit: structural and evolutionary implications

Sequencing of the subunit of the hemocyanin of Octopus dofleini has been completed from a cDNA library. This represents the first molluscan hemocyanin to be completely sequenced. The sequence determined is for one of the two distinguishable cDNAs which have been recognized for this protein. The protein subunit has 2896 amino acids and contains seven functional units, each carrying two sets of three invariant histidine residues constituting the binding sites (A and B) for two copper atoms. The accompanying paper identifies this site in the C-terminal functional unit (Odg). Differences in sequence for the two cDNAs, for the region in which both are available, are concentrated in the “linker regions” between functional units. The sequences of the seven units exhibit high similarity, averaging about 40% identity, with a concentration of conserved sequences in the region surrounding the copper binding sites. The sequences around the B-site show significant homology to the sequences of arthropod hemocyanins. Comparison of the functional unit sequences in terms of hydrophobicity and surface exposure profiles, as well as regions of probable secondary structure, indicate that all functional units probably have a common tertiary folding; the protein subunit is a string of similarly folded beads. A number of putative N-linked carbohydrate binding sites can be recognized in the sequence; one of these corresponds to the carbohydrate observed in the X-ray diffraction study of functional unit Odg as disclosed in the accompying paper. Phylogenetic analysis of the sequences of the O. dofleini functional units, and comparison with other available molluscan sequences indicates that the multi-domain subunit structure must have arisen over a relatively brief period, preceeding the differentiation of major molluscan types.

Some Aspects of Diet and Foraging Behavior of Octopus dofleini Wülker, 1910 in its Northernmost Range

Abstract. Diet and foraging behavior of Octopus dofleini in Prince William Sound and Port Graham, Alaska, were studied from collections of den litter, measurements of octopuses and estimates of live prey abundance. Based on 193 den collections from depths of ‐ 31 to + 1.3 m, a diet of hard‐bodied prey could be identified. The five most common litter species made up 80% of the litter remains, with nearly 30 species of various taxa malung up the rest. The proportions of major hard‐bodied prey species in each litter pile significantly differed with depth of den, associated substrata, presence of cobble and geographical location but not with the presence of boulders or outcrop, the density of kelp or season of litter collection. Octopus weight was not significantly correlated with the size of prey remains although O. dofleini may take a wide range of prey sizes once it reaches 2.5 kg. O. dofleini was more likely to be found at sites with crabs, although no litter species was significantly preferred over its estimated abundance, and one species was significantly avoided. These results suggest that O. dofleini includes suitable bivalve and crab species in its diet in relation to live abundance, while at the same time exercising an element of selectivity, as some species were actively avoided. Comparison of litter remains from the northern‐most range of O. dofleini with those published for British Columbia show that diet breadth was similar, but the identity of major hard‐bodied prey species was very different for Alaskan octopuses.

青森県尻屋崎周辺海域におけるミズダコの性成熟

The maturity of the north Pacific giant octopus Octopus dofleini and its mating season were investigated by regular samplings during the period from November 1992 to November 1993. The sampling area was the coastal waters off the northern tip of Honshu (Cape Shiriya, Shimokita Peninsula, Aomori pref.). Females were classified into immature and mature stage by coloration of the ovary. In males, maturation stages were classified into three stages: mature stage by the length of spermatophore exceeding 70cm long; maturing stage by the length of spermatophore less than 70cm long; and immature stage by the absence of spermatophore. Mature females appeared from January to May. Male maturing specimens were present from March to December and mature ones appeared from December to May. Immature specimens of both sexes were taken throughout the year. Mated females were caught from January to April. The number of ovarian eggs ranged from 38, 000 to 94, 000.

Morphology, egg cocoons, and transmission paths of the Antarctic leech Glyptonotobdella antarctica Sawyer and White, 1969 (Hirudinea: Rhynchobdelliformes: Piscicolidae)

The biology of piscicolids which move between different host species is poorly understood. Very little is known about leeches of Antarctic waters, though they are not uncommon in that region. This paper adds to the fundamental knowledge of the Antarctic piscicolid leech Glyptonotobdella antarctica Sawyer and White, 1969. According to the new findings the distribution of the species has to be extended to the geographical latitude of 76°08.1′S and to a depth of 665 m. Besides Glyptonotus antarcticus Eights 1853, sea urchins of the genus Sterechinus (Meissner 1900), and the benthic octopus Pareledone (charcoti?) (Joubin 1905) serve as hosts. Hitherto there were only two records on piscicolids from Octopus dofleini and none from sea urchins. Egg cocoons on the ventral side of the isopod Glyptonotus antarcticus were attributed to the leech. Most likely Glyptonotobdella antarctica moves between different hosts, i.e. Antarctic octopuses and their potential prey. Surface structures of the leech are studied by light and scanning electron microscope. The observations complement the basic knowledge on Antarctic leeches and provide arguments for phylogenetic discussions.

Aldehyde dehydrogenase-derived omega-crystallins of squid and octopus. Specialization for lens expression

omega-Crystallin of the octopus lens is related to aldehyde dehydrogenases (ALDH) of vertebrates (Tomarev, S. I., Zinovieva, R. D., and Piatigorsky, J. (1991) J. Biol. Chem. 266, 24226-24231) and ALDH1/eta-crystallin of elephant shrews (Wistow, G., and Kim, H. (1991) J. Mol. Evol. 32, 262-269). Only very low amounts of omega-crystallin are present in the squid lens. Here, we have cloned omega-crystallin cDNAs of the octopus (Octopus dofleini) and squid (Ommastrephes sloani pacificus) lenses. The deduced amino acid sequences of omega-crystallin from these species are 78% identical to each other, 56-58% identical to cytoplasmic ALDH1 and mitochondrial ALDH2 of vertebrates (which are 66-68% identical to each other), and 40% identical to Escherichia coli and spinach ALDHs. These data are consistent with the idea that the ALDH1/ALDH2 gene duplication in vertebrates occurred after divergence of cephalopods from the line giving rise to vertebrates, but before the separation of squid and octopus. Southern blot hybridization indicated that omega-crystallin is encoded by few genes (possibly just one) in octopus and squid. Northern blot hybridization revealed two bands (2.7 and 9.0 kilobases) of omega-crystallin RNA in the octopus lens and one band (4.2 kilobases) in the squid lens; omega-crystallin RNAs were undetectable in numerous non-lens tissues of octopus and squid, suggesting lens-specific expression of this gene(s). Finally, extracts of the octopus lens had no detectable ALDH activity using different substrates, consistent with omega-crystallin having no enzymatic activity. Taken together, our results suggest that omega-crystallin evolved by duplication of an ancestral gene encoding ALDH and subsequently specialized for refraction in the transparent lens while losing ALDH activity and expression in other tissues.

Design and synthesis of model systems for oxygen binding and activation in dinuclear copper proteins.

Following the spectroscopic1,2 and crystallographie3,6 characterization of the dinuclear copper site of hemocyanin, the coordination chemistry of models for such sites was developed7,8. Nature employs the dinuclear copper site for binding of dioxygen, as found in the hemocyanins, the oxygen transport proteins of molluscs and arthropods. It is also employed in enzymes, such as tyrosinase9, and, in combination with copper ions representing other types of biological copper, lacease10 and ascorbate oxidase11, for the activation of dioxygen. Interestingly, protons and chloride ions affect the cooperativity of the oxygen binding by Panulirus interruptus (spiny lobster)12 and Limulus polyphemus (horseshoe crab)13 hemocyanin, respectively, whereas the aggregation of Octopus dofleini (Pacific octopus) hemocyanin subunits to form a functional unit is controlled by magnesium ions14. Recent crystal structures and spectroscopic studies5,6,15 of oxy- and deoxy-hemocyanin under a variety of circumstances have given indications that these effects may operate at the level of control of the Cu-Cu distance.

Aggregata dobelli N. Sp. and Aggregata millerorum N. Sp. (Apicomplexa: Aggregatidae) from Two Species of Octopus (Mollusca: Octopodidae) from the Eastern North Pacific Ocean

ABSTRACT. Gamogony and sporogony of two new species of Aggregata (Apicomplexa: Aggregatidae) commonly were observed during histopathological examination of the digestive tracts of octopuses from the National Aquarium in Baltimore. North Pacific giant octopus, Octopus dofleini martini Pickford 1964, from British Columbia and Washington state were infected with Aggregata dobelli n. sp. Sporocysts were smooth‐surfaced, dark‐staining, subspherical to subovoid, typically 18–31 μm long by 15–27 μm wide, and contained 9–22 sporozoites, 18–23 μm long. California two‐spotted octopus, Octopus bimaculoides Pickford and McConnaughey 1949, from California were infected with Aggregata millerorum n. sp. Sporocysts were smooth‐surfaced, dark‐staining, and subspherical to subovoid, 12–20 μm long by 11–17 μm wide, and contained 8–10 sporozoites, 18–31 μm long. Both species infected the noncuticularized spiral caecum and intestine; A. millerorum n. sp. also infected the cuticularized esophagus and crop. Both parasites were present in the submucosa, muscularis, and serosa. Our observations of Aggregata infections in cuticularized regions of the gut and in the muscularis and serosa appear to be novel. Associated pathologic features included hypertrophy of invaded cells, edema, inflammation, and ulceration.

Entry of pollutants from seawater into the spermatophore and spermatozoa of the giant octopus of the North Pacific

Copulation in the giant octopus of the North Pacific, Octopus dofleini martini, takes place in seawater and lasts 2 h. During that time the spermatophore undergoes the spermatophoric reaction resulting in the transfer of spermatozoa to the female. Methylmercuric chloride and several organochlorine pollutants enter readily the spermatophore during the sphermatophoric reaction and accumulate in the spermatozoa at surprisingly high concentrations, in some instances exceeding many fold the levels in the seawater.

Characterization of boreholes by Octopus dofleini in the bivalve Saxidomus giganteus

Octopus dofleini (Wulker) drills holes in mollusc shells, enabling it to introduce venom. Boreholes in the bivalve Saxidomus giganteus (Deshayes) were generally irregular. Thick shells were more likely to have incomplete boreholes, and the diameter of completed boreholes was larger than in thin shells. A comparison of boreholes to fractured and artificially drilled surfaces suggests that O. dofleini employs chemical dissolution of the shell during drilling.

ASSESSING NORTHERN ELEPHANT SEAL FEEDING HABITS BY STOMACH LAVAGE

AbstractStomach lavaging was used to study the feeding habits of northern elephant seals (Mirounga angustirostris) found on San Miguel Island, California, during the spring of 1984. Fifty‐nine elephant seals were chemically immobilized with an intramuscular injection of ketamine hydrochloride. Once immobilized, an animal's stomach was intubated, filled with 3–4 liters of water to create a slurry of the undigested food items, and evacuated into a collection device. The stomachs of 57 (96.6%) of the animals lavaged contained identifiable parts of prey. Twenty‐nine different food items were identified, 12 of which have not been previously reported as prey of the northern elephant seal: two teleost fish, Coryphaenoides acrolepis (Pacific rattail) and another unidentified macrourid; two crustaceans, Pasiphaea pacifica (glass shrimp) and Euphausia sp.; six squid, Abraliopsis felis, Gonatus berryi, Histioteuthis dofleini, Cranchia scabra, Taonius pavo, and Galiteuthis sp. and two octopi, Octopus dofleini and Octopus rubescens.

Analysis of growth based on tag‐recapture of the Giant Pacific octopus Octopus dofleini martini

In total, 211 octopuses were tagged and 87 (41·2%) of these were recaptured, some up to eight times for a total of 184 recaptures. Octopuses ranged in wet weight from 1·6 to 20 kg and the sex ratio was skewed towards females. No difference was found in the growth rates between sexes or locations and growth rates were variable for all sizes studied. Evidence for two distinct growth periods was found; a slow period from January to June and a faster period from July to December. Separate growth curves were drawn for each period and their relevance to potential growth in the field discussed. Growth rates of O. dofleini were comparable to those described for other octopod species.A tag‐recapture growth study of Octopus dofleini martini was conducted at two inshore, shallow water (2–15 m) sites in Clayoquot Sound, British Columbia. The objective was to describe the growth of O. dofleini in the field and investigate variation related to sex, season or location.

Phosphoglycopeptide, a major constituent of the spermatophoric plasma of the octopus (Octopus dofleini martini)

A phosphoglycopeptide, accounting for approximately 90% of the characteristically high content of acid-soluble organically-bound phosphorus in the octopus spermatophoric plasma (4 mg P/ml), was identified. Electrophoretic and chromatographic purification, followed by chemical and enzymic hydrolysis, yielded D-galactose phosphate as a degradation product. The galactose and peptide moieties of the compound were linked via a phosphoryl rather than a glycosidic linkage but the peptide was devoid of aromatic amino acids.

Elastic Arteries in Invertebrates: Mechanics of the Octopus Aorta

The aorta of the octopus, Octopus dofleini, is a highly distensible, elastic tube. The circumferential elastic modulus increases with inflation in the physiological range from abut 10(4) to 10(5) newtons per square meter. Rubber-like fibers have been isolated, apparently for the first time, from the aorta of an invertebrate. These fibers have an elastic modulus, like elastin, of about 4 x 10(5) newtons per square meter and are present in sufficient quantity to account for the elastic properties of the intact vessel under physiological conditions. Thus the circulatory system of an invertebrate animal provides an "elastic reservoir" (much like that of the vertebrate system), which increases the efficiency of the circulation.

Cornea regeneration in the Pacific giant octopus,Octopus dofleini, and the common octopus,O. vulgaris

Cornea regeneration in a Pacific giant octopus, Octopus dofleini, occurred within 10 days after the injury was observed. Surgical removal of the cornea in a common octopi, O. vulgaris experimentally duplicated this cornea regeneration within a 10-day period. It is, therefore, concluded that besides sucking discs, arms, and nerve fibres, octopi can also regenerate corneal tissue.

Changes in the spermatophoric plasma during spermatophore development and during the spermatophoric reaction in the giant octopus of the north pacific, Octopus dofleini martini

Concentrations of Na, K, Cl, Ca and Mg were measured in the spermatophoric plasma and certain other body fluids of Octopus dofleini martini. The most striking change associated with maturation and passage of the spermatophore in the male reproductive tract, was a decline in the concentration of NaCl in the spermatophoric plasma. This was completely reversed during the spermatophoric reaction owing to influx of salt from the seawater. The outer tunic of a spermatophore undergoing spermatophoric reaction is also permeable to other substances. It allows an influx of inorganic phosphate and glucose, and an efflux of organically bound nitrogen, carbohydrate and aminosugar.

A removal experiment with Octopus dofleini (Wulker)

All Octopus dofleini martini were removed from a study area in Clayoquot Sound, B.C., during a 6-wk period, and they and their dens were measured. There was an exponential relation between octopus size and the size of den it occupied. In addition, small octopus tended to be found in newly dug dens, while large ones occupied natural dens. Some dens from which octopuses were removed were recolonized by animals of similar size but many remained empty and new dens were often dug in areas where dens already existed. Immigration of octopuses into the control area at the same time suggests that the observed recruitment was not brought about by the harvest. Females were more numerous than males, especially in the smallest sizes. Our study points toward the feasibility of a size-selective trap fishery. Key words: octopus, harvest, recruitment, denning, predation