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Tintenfisch

Architeuthis
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D, I thought the same thing about squid until I was out with MBARI and I don't think we saw a single squid swimming the way I thought all squid swam (i.e., plain old horizontally). The histioteuthids were somewhere between vertical and 45 degrees, many others had the mantle at about 45 and then the head/arms bent around to more horizontal, Taonius often swam straight up and down, and Galiteuthis liked to sit with the mantle horizontal and the arms all gathered vertically into the cockatoo pose. That was one of my main take-home messages from the trip: few squid (at least in the deep sea in Monterey) swim the way I had previously envisioned most/all squid to swim.
 

DWhatley

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The Complete Mitochondrial Genomes of Two Octopods Cistopus chinensis andCistopus taiwanicus: Revealing the Phylogenetic Position of the Genus Cistopuswithin the Order Octopoda
Rubin Cheng,Xiaodong Zheng mail,Yuanyuan Ma, Qi Li 2013 (full text)

Abstract
In the present study, we determined the complete mitochondrial DNA (mtDNA) sequences of two species of Cistopus, namely C. chinensis and C. taiwanicus, and conducted a comparative mt genome analysis across the class Cephalopoda. The mtDNA length of C. chinensis and C. taiwanicus are 15706 and 15793 nucleotides with an AT content of 76.21% and 76.5%, respectively. The sequence identity of mtDNA between C. chinensis and C. taiwanicus was 88%, suggesting a close relationship. Compared with C. taiwanicus and other octopods, C. chinensis encoded two additional tRNA genes, showing a novel gene arrangement. In addition, an unusual 23 poly (A) signal structure is found in the ATP8 coding region of C. chinensis. The entire genome and each protein coding gene of the two Cistopus species displayed notable levels of AT and GC skews. Based on sliding window analysis among Octopodiformes, ND1 and DN5 were considered to be more reliable molecular beacons. Phylogenetic analyses based on the 13 protein-coding genes revealed that C. chinensis and C. taiwanicus form a monophyletic group with high statistical support, consistent with previous studies based on morphological characteristics. Our results also indicated that the phylogenetic position of the genus Cistopus is closer to Octopus than to Amphioctopus and Callistoctopus. The complete mtDNA sequence of C. chinensis and C. taiwanicus represent the first whole mt genomes in the genus Cistopus. These novel mtDNA data will be important in refining the phylogenetic relationships within Octopodiformes and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of Cephalopoda
 

DWhatley

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Proteomic characterization of the hemolymph of Octopus vulgaris infected by the protozoan parasite Aggregata octopiana
Sheila Castellanos-Martínez, Angel P. Diz, Paula Álvarez-Chaver, Camino Gestal 2013 (subscription)

The immune system of cephalopods is poorly known to date. The lack of genomic information makes difficult to understand vital processes like immune defense mechanisms and their interaction with pathogens at molecular level. The common octopus Octopus vulgaris has a high economic relevance and potential for aquaculture. However, disease outbreaks provoke serious reductions in production with potentially severe economic losses. In this study, a proteomic approach is used to analyze the immune response of O.vulgarisagainst the coccidia Aggregata octopiana, a gastrointestinal parasite which impairs the cephalopod nutritional status. The hemocytes and plasma proteomes were compared by 2-DE between sick and healthy octopus. The identities of 12 differentially expressed spots and other 27 spots without significant alteration from hemocytes, and 5 spots from plasma, were determined by mass spectrometry analysis aided by a six reading-frames translation of an octopus hemocytes RNA-seq database and also public databases. Principal component analysis pointed to 7 proteins from hemocytes as the major contributors to the overall difference between levels of infection and so could be considered as potential biomarkers. Particularly, filamin, fascin and peroxiredoxin are highlighted because of their implication in octopus immune defense activity. From the octopus plasma, hemocyanin was identified. This work represents a first step forward in order to characterize the protein profile of O.vulgaris hemolymph, providing important information for subsequent studies of the octopus immune system at molecular level and also to the understanding of the basis of octopus tolerance-resistance to Aoctopiana.

Another immune system paper - S. Officinalis
Hemocyte morphology and phagocytic activity in the common cuttlefish (Sepia officinalis) Charles Le Pabic, Didier Goux, Maryline Guillamin, Georges Safi, Jean-Marc, Noussithé, Antoine Serpentini 2014 (subscription)

Abstract
Little is known about the immune system of cephalopods, in spite of their many highly derived characters within the molluscan clade, including a vertebrate-like high-pressure closed circulatory system. Further the economic importance of cephalopod fisheries, potential for aquaculture, and use as ecotoxicology models demand a thorough understanding of their immune system. In this study, we present a comprehensive characterization of hemocytes in the common cuttlefish Sepia officinalis. Cytological stainings, electron microscopy- and flow cytometry-observations highlight a single granulocyte population with various densities of eosinophilic granules and unstained vesicles. These hemocytes contain acid phosphatase-, lysozyme- and proPO system enzymes, and have high activity in bead phagocytosis assays. Interestingly, bead pre-incubation in plasma results in timedependent aggregation perhaps resulting from hemocyanin-coating, and decrease in phagocytosis. This study provides the basis for understanding hemocyte-mediated immunity in the common cuttlefish, and essential background for future studies on cephalopod immunity.
 
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DWhatley

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Defensive Responses of Cuttlefish to Different Teleost Predators
Michelle D. Staudingera,Kendra C. Buresch, Lydia M. Mäthger,Charlie Fry, Sarah Mcanulty, Kimberly M. Ulmer, Roger T. Hanlon
2014 (subscription)

Abstract
We evaluated cuttlefish (Sepia officinalis) responses to three teleost predators: bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus), and black seabass (Centropristis striata). We hypothesized that the distinct body shapes, swimming behaviors, and predation tactics exhibited by the three fishes would elicit markedly different antipredator responses by cuttlefish. Over the course of 25 predator-prey behavioral trials, 3 primary and 15 secondary defense behaviors of cuttlefish were shown to predators. In contrast, secondary defenses were not shown during control trials in which predators were absent. With seabass—a benthic, sit-and-pursue predator—cuttlefish used flight and spent more time swimming in the water column than with other predators. With bluefish—an active, pelagic searching predator—cuttlefish remained closely associated with the substrate and relied more on cryptic behaviors. Startle (deimatic) displays were the most frequent secondary defense shown to seabass and bluefish, particularly the Dark eye ring and Deimatic spot displays. We were unable to evaluate secondary defenses by cuttlefish to flounder—a lie-and-wait predator—because flounder did not pursue cuttlefish or make attacks. Nonetheless, cuttlefish used primary defense during flounder trials, alternating between cryptic still and moving behaviors. Overall, our results suggest that cuttlefish may vary their behavior in the presence of different teleost predators: cryptic behaviors may be more important in the presence of active searching predators (e.g., bluefish), while conspicuous movements such as swimming in the water column and startle displays may be more prevalent with relatively sedentary, bottom-associated predators (e.g., seabass).
 

DWhatley

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Ink From Longfin Inshore Squid,Doryteuthis pealeii, as a Chemical and Visual Defense Against Two Predatory Fishes, Summer Flounder, Paralichthys dentatus, and Sea Catfish, Ariopsis felis
Charles D. Derby, Mihika Tottempudi, Tiffany Love-Chezem, Lanna S. Wolfe
2014 (subscription)

Abstract
Chemical and visual defenses are used by many organisms to avoid being approached or eaten by predators. An example is inking molluscs—including gastropods such as sea hares and cephalopods such as squid, cuttlefish, and octopus—which release a colored ink upon approach or attack. Previous work showed that ink can protect molluscs through a combination of chemical, visual, and other effects. In this study, we examined the effects of ink from longfin inshore squid, Doryteuthis pealeii, on the behavior of two species of predatory fishes, summer flounder, Paralichthys dentatus, and sea catfish, Ariopsis felis. Using a cloud assay, we found that ink from longfin inshore squid affected the approach phase of predation by summer flounder, primarily through its visual effects. Using a food assay, we found that the ink affected the consummatory and ingestive phase of predation of both sea catfish and summer flounder, through the ink's chemical properties. Fractionation of ink showed that most of its deterrent chemical activity is associated with melanin granules, suggesting that either compounds adhering to these granules or melanin itself are the most biologically active. This work provides the basis for a comparative approach to identify deterrent molecules from inking cephalopods and to examine neural mechanisms whereby these chemicals affect behavior of fish, using the sea catfish as a chemosensory model.
 

DWhatley

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tonmo

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Hey @gjbarord, note the cuttlebone paper above...

New paper:

Structure and mechanical properties of Octopus vulgaris suckers
Francesca Tramacere, Alexander Kovalev, Thomas Kleinteich, Stanislav N. Gorb, and Barbara Mazzolai

Abstract
In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ∼ 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers.

Keywords: octopus suckers, suction cup, elasticity modulus, viscoelasticity, bioinspiration
 

DWhatley

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Evolution of spermatophore transfer mechanisms in cephalopods
José Eduardo Amoroso Rodriguez Marian 2013 (subscription)

Abstract
Spermatophores from coleoid cephalopods are capable of functioning autonomously during mating, attaching themselves to the female body through the “spermatophoric reaction”. In decapodiforms this attachment involves some varying degree of implantation into female tissue, herein divided into shallow and deep implantation. This paper reviews the literature concerning the phenomenon of spermatophore implantation, and presents evidence corroborating a theoretical model ascribing the role of implantation to the ejaculatory apparatus, an invaginated tube found in the spermatophore oral region. In light of parsimonious character optimizations performed on published phylogenetic trees, two hypotheses for the evolution of spermatophore transfer mechanisms are tested. One hypothesis assumes that deep implantation arose first, shallow implantation evolving later associated with the emergence of specialized receptacles. The second hypothesis assumes that shallow implantation emerged first, deep implantation arising later, possibly associated with the adoption of deep-water lifestyles. Support for each hypothesis is dependent upon the phylogeny under consideration.
 

DWhatley

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Utilization of diets with different fish oil content in common octopus (Octopus vulgaris Cuvier, 1797) and resulting changes in its biochemical composition
Piedad S Morillo-Velarde, Jesús Cerezo Valverde, Benjamín García-García 2014 (subscription)

Abstract
The aim of the present work was to obtain the lipid utilization of Octopus vulgaris supplying formulated semi-moist diets with different contents in cod oil (reduced from water content): 0 g kg−1 (A0, 138 g kg−1 lipids DW; N = 4), 100 g kg−1 (A100, 286 g kg−1 lipids DW; N = 6) and 200 g kg−1 (A200, 388 g kg−1 lipids DW; N = 6). The rest of the ingredients were constant in the three diets: 200 g kg−1 gelatin, 100 g kg−1 egg yolk powder, 150 g kg−1 freeze-dried Todarodes sagittatus and 50 g kg−1 freeze-dried Sardinella aurita). Survival was 100% with the three diets. The highest absolute feeding (15.8 ± 1.2 g day−1), growth (9.6 ± 1.4 g day−1; 0.91% BW day−1) and feed efficiency rates (60.3%) were obtained with diet A0. This diet also showed greater retention of lipid and protein than A100 and A200. Protein digestibility was above 95% in all of the diets. Only diet A0 led to a high lipid digestibility coefficient (81.25%), which fell drastically to 12.3% in A200. It was notable the high polar lipid digestibility rates (83–89%) respect to neutral lipids (2–87%) in all diets. The best results were obtained with lipid feeding rates of around 1 g day−1 and a suitable lipid content on 130–140 g kg−1 DW in formulated diets for O. vulgaris.
 

DWhatley

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Close Genetic Relationships between Two American Octopuses: Octopus hubbsorum Berry, 1953, and Octopus mimus Gould, 1852
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Ricardo Pliego-Cárdenas ,Frederick G. Hochberg , Francisco Javier García De León, Irene De Los Angeles Barriga-Sosa

ABSTRACT

The octopuses Octopus hubbsorum and Octopus mimus are two species of octopuses that inhabit shallow waters of the eastern Pacific Ocean. The former species is found in the north, from the Gulf of California to Oaxaca, Mexico, whereas O. mimus lives in the south, from Peru to Chile. To infer the phylogenetic relationships between these species we used the mitochondrial genes cytochrome oxidase subunits I and III, and r16S with the aim of comparing their genetic distances with those of other Octopus sp. The genetic distance values between both species estimated per gene or concatenated were low (0%–1.6%) in comparison with other interspecific distances values (4.6%–18.4%). Application of 10× rule showed there is no overlap between intra- and interspecific octopus distances, whereas the application of the 4× rule confirmed that both octopuses belong to the same lineage. The resolved topologies with maximum parsimony and Bayesian approaches clustered the specimens of O. hubbsorum and O. mimus in a single clade with high bootstrap and posterior probability values (100 and 1.0, respectively). These results allow us to suggest that O. hubbsorum and O. mimus could represent the same species.
 
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