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.     

Malabsorption syndrome observed in the common octopus Octopus vulgaris infected with Aggregata octopiana (Protista: Apicomplexa)

Octopus vulgaris infected with Aggregata octopiana were collected from an open-water culture system in the Ría of Aldán (NW Spain). Digestive tract infection values were determined with the use of a Neubauer chamber by counting the number of A. octopiana sporocysts. After determining enzyme activity values by the colorimetric Api-Zym system Biomerieux, one representative enzyme of glycosidases, peptid hydrolases and phosphoric hydrolases showing high activity was spectrophotometrically analysed. The enzymes were maltase and leucine-aminopeptidase (LAP) involved in the absorption process, and acid phosphatase, a lysosomic enzyme, respectively. Enzymatic activity of maltase and LAP decreased significantly, with increased sporocyst counts. However, acid phosphatase activity increased with severity of infection, indicating the presence of degradative enzymes from phagocytic cells in the infected area. A detrimental effect on gastrointestinal function may result from a decrease or malfunction of absorption enzymes. The results suggest a malabsorption syndrome resulting from parasitic infection.     

Role of the tertiary structure in the diphenol oxidase activity of Octopus vulgaris hemocyanin

The functional differences between the oxygen transport protein Hemocyanin and the enzymes Tyrosinase and Catechol oxidase are believed to be governed, at least in part, by the tertiary structure, which differs in these molecules and controls the accessibility of their copper containing active site for substrate(s). Accordingly, Octopus vulgaris Hemocyanin catalyses the o-diphenol oxidation to o-quinone at a very low rate. The crystallographic structure of one of the functional units (called Odg) of O. dofleini Hemocyanin shows two domains, a mainly α-helical domain that directly binds the copper ions of the reaction center and a β-strand domain that precludes access to the active site to ligands bigger than molecular oxygen. In this work, we have first cleaved the whole protein and then purified different oxygen binding functional units from O. vulgaris Hemocyanin. These functional units were used in activity assays with l-DOPA, the paradigmatic substrate for Catechol oxidase. All functional units show a negligible enzymatic activity. The procedure to generate the functional units induces in only one of them a proteolytic cleavage. Amino terminal sequencing and mass spectroscopy of the fragments allow to place the cleavage site between the alpha and beta domains of the functional unit homologous to Odd, in the O. dofleini sequence. An increase, up to three orders of magnitude, of Tyrosinase-like activity was observed when the cleaved Odd-like was incubated with the substrate in the presence of trifluoroethanol or hexafluoroisopropanol.     

Isolation and characterization of Glyceraldehyde-3-phosphate dehydrogenase from the common octopus (<Emphasis Type="Italic">Octopus vulgaris </Emphasis>Cuvier, 1797)

The NAD⁺ dependent cytosolic Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) from arms of Octopus vulgaris, Cuvier, 1787, (Octopoda, Cephalopoda) was purified to homogeneity and its kinetic properties investigated. The purification method consisted of ammonium sulfate fractionation followed by Blue Sepharose CL-6B chromatography resulting in a 26-fold increase in specific activity and a final yield of approximately 16%. The apparent molecular weight of the purified native enzyme was 153 kDa. The protein is an homotetramer, composed of identical subunits with an apparent molecular weight of approximately 36 kDa. The Michaelis constants K_m for both NAD⁺ and d-G3P were 66 μM and 320 μM, respectively. The maximal velocity V_max of the purified enzyme was estimated to be 21.8 U/mg. Only one GAPDH isoform (pI 6.6) was obtained by isoelectrofocusing in polyacrylamide slab gels holding ampholyte generated pH gradients. Under the conditions of assay, the optimum activity occurs at pH 7.0 and at temperature of 35°C. Polyclonal antibodies raised in rabbits against the purified GAPDH immunostained a single 36 kDa GAPDH band on crude extract protein preparations blotted onto nitrocellulose.     

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 μ m long by 15–27 μ m wide, and contained 9–22 sporozoites, 18–23 μ m 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 μ m long by 11–17 μ m wide, and contained 8–10 sporozoites, 18–31 μ m 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.     

Secondary sensory cells in the gravity receptor system of the statocyst of Octopus vulgaris

Summary The presence of secondary sensory cells in the Octopus gravity receptor system has been demonstrated. In serial thin sections of the receptor cells (hair cells) no axons were found leaving the cells. Instead, synapses were observed with synaptic vesicles lying inside the receptor cells. Both data clearly indicate that the receptor hair cells represent secondary sensory cells. In addition, efferent contacts to the receptor cells could be confirmed.This work was supported in part by grant Wo 160/5 of the Deutsche Forschungsgemeinschaft to Prof. Dr. H.G. WolffThe experimental work was done in part at the Zoological Station in Naples and at the Sechenov Institute of Evolutionary Physiology and Biochemistry of the USSR Academy of Sciences (Laboratory of Prof. Dr. Ya.A. Vinnikov), Leningrad, USSR. The authors thank Prof. Vinnikov and Dr. Tsirulis for stimulating discussions     

Evidence for acetylcholine as a neurotransmitter in the statocyst of Octopus vulgaris

Summary Evidence is presented for acetylcholine as neurotransmitter in the sensory epithelia (macula and crista) of the statocyst of Octopus vulgaris, based on the following techniques: (i) histochemical assay of acetylcholinesterase at light- and electron-microscopical levels, in combination with the detailed knowledge of the ultrastructural and neuronal organization of the receptor epithelia; (ii) lesion/degeneration experiments of the efferent fibre system; (iii) radiochemical assay of acetylcholine; and (iv) bioassay of acetylcholine. All data support the hypothesis that in the statocyst of O. vulgaris acetylcholine acts as a neurotransmitter in the efferent fibre system.This paper is dedicated to Professor Franz Huber, Seewiesen, on the occasion of his 60th birthday     

Evidence for genetic differentiation of Octopus vulgaris (Mollusca, Cephalopoda) fishery populations from the southern coast of Brazil as revealed by microsatellites

Octopus vulgaris is a cephalopod species in several oceans and commonly caught by artisanal and industrial fisheries. In Brazil, O. vulgaris populations are mainly distributed along the southern coast and have been subjected to intensive fishing during recent years. Despite the importance of this marine resource, no genetic study has been carried out to examine genetic differences among populations along the coast of Brazil. In this study, 343 individuals collected by commercial vessels were genotyped at six microsatellite loci to investigate the genetic differences in O. vulgaris populations along the southern coast of Brazil. Genetic structure and levels of differentiation among sampling sites were estimated via a genotype assignment test and F-statistics. Our results indicate that the O. vulgaris stock consists of four genetic populations with an overall significant analogous F_ST (Φ_CT = 0.10710, P < 0.05) value. The genetic diversity was high with an observed heterozygosity of Ho = 0.987. The negative values of F_IS found for most of the loci examined suggested a possible bottleneck process. These findings are important for further steps toward more sustainable octopus fisheries, so that this marine resource can be preserved for long-term utilization.     

Histochemical evidence for catecholamines as neurotransmitters in the statocyst of Octopus vulgaris

Summary Formaldehyde-induced fluorescence (Falck-Hillarp technique) provided histochemical evidence for the presence of catecholamines in the sensory epithelia (macula and crista) of the Octopus statocyst. A specific bright green fluorescence occurred in the neuronal plexus beneath the receptor cell layers of the epithelia and in the appropriate nerves. The histochemical findings are discussed with reference to the well-known neuronal and synaptic organization of the epithelia and to relevant results in cephalopods as well as in other molluscs. All data support the hypothesis that in the receptor systems of the Octopus statocyst catecholamines (probably dopamine and/or noradrenaline) act as neurotransmitters in the efferent fibre system.     

Larval nematodes (Spiruroidea: Cystidicolidae) in Octopus vulgaris (Mollusca: Cephalopoda: Octopodidae) from the northeastern Atlantic Ocean.

Larval nematode parasites (Spiruroidea: Cystidicolidae) are recorded for the first time in Octopus vulgaris Cuvier, 1797 in the northeastern Atlantic Ocean. Prevalence was 16% and mean intensity was 1.46 worms/host. Body length of larval nematodes ranges from 8.3 to 9.3 mm, with a distance from the anterior end to nerve ring from 187.5 to 200 microm, and to excretory pore 194.6-350 microm. Anatomical characteristics, such as deirid, nerve ring, cephalic alae, excretory pore, pseudolabia amphids, sclerotized protuberance, and anus, examined using light microscopy (LM) or scanning electron microscopy (SEM), are illustrated. The nematode was designed as a cystidicolid "Type A" larva. The hemocytic infiltration present in the host tissue around the nematode capsule and the mechanical compression in the infected organs denote the pathogenicity of this nematode. In the study area, O. vulgaris may play the role of an intermediate or paratenic host in the nematode life cycle.     

The early life of Octopus vulgaris (Cephalopoda: Octopodidae) in the plankton and at settlement: a change in lifestyle

Newly hatched young of the benthic, coastal-living octopod, Octopus vulgaris , enter the plankton and remain there for perhaps eight weeks. At hatching the arms are short and bear a few, large, primary suckers. The buccal mass is relatively large in proportion to the size of the animal. The eyes are large. The central nervous system has fairly well-defined lobes, some of which develop earlier than others. We shall follow the development of several features of O. vulgaris from hatching, through its life in the plankton until settlement and correlate them with changes in the brain and behaviour.     

Multiple origins of the determinate growth habit in domesticated common bean (Phaseolus vulgaris)

Background and Aims

The actual number of domestications of a crop is one of the key questions in domestication studies. Answers to this question have generally been based on relationships between wild progenitors and domesticated descendants determined with anonymous molecular markers. In this study, this question was investigated by determining the number of instances a domestication phenotype had been selected in a crop species. One of the traits that appeared during domestication of common bean (Phaseolus vulgaris) is determinacy, in which stems end with a terminal inflorescence. It has been shown earlier that a homologue of the arabidopsis TFL1 gene – PvTFL1y – controls determinacy in a naturally occurring variation of common bean.

Methods

Sequence variation was analysed for PvTFL1y in a sample of 46 wild and domesticated accessions that included determinate and indeterminate accessions.

Key Results

Indeterminate types – wild and domesticated – showed only synonymous nucleotide substitutions. Determinate types – observed only among domesticated accessions – showed, in addition to synonymous substitutions, non-synonymous substitutions, indels, a putative intron-splicing failure, a retrotransposon insertion and a deletion of the entire locus. The retrotransposon insertion was observed in 70 % of determinate cultivars, in the Americas and elsewhere. Other determinate mutants had a more restricted distribution in the Americas only, either in the Andean or in the Mesoamerican gene pool of common bean.

Conclusions

Although each of the determinacy haplotypes probably does not represent distinct domestication events, they are consistent with the multiple (seven) domestication pattern in the genus Phaseolus. The predominance of determinacy in the Andean gene pool may reflect domestication of common bean prior to maize introduction in the Andes.     

Localization of corticotropin-releasing factor-immunoreactive nervous tissue and colocalization with neuropeptide Y-like substance in the optic lobe and peduncle complex of the octopus (<Emphasis Type="Italic">Octopus vulgaris</Emphasis>)

The distribution of corticotropin-releasing factor (CRF)-like immunoreactivity and its colocalization with neuropeptide Y (NPY)-like substances were investigated in the optic lobe and peduncle complex of the octopus (Octopus vulgaris) using immunohistochemical techniques. In the optic lobe cortex, CRF-immunoreactive (CRF-IR) and NPY-immunonegative varicose fibers were observed in the plexiform layer. In the medulla, CRF-IR somata were seen in the cell islands, and CRF-IR varicose fibers were observed in the neuropil. About half of the CRF-IR structures in the medulla showed NPY-like immunoreactivity. In the peduncle lobe, no CRF-IR somata but abundant CRF-IR varicose fibers were observed, and about half of them showed NPY-like immunoreactivity. In the olfactory lobe, CRF-IR somata and abundant CRF-IR varicose fibers were observed. Almost all the CRF-IR somata located in the posterior olfactory lobule showed NPY-like immunoreactivity, whereas those seen in the median olfactory lobule were immunonegative for NPY. About half of the CRF-IR fibers in the anterior lobule neuropil were immunopositive for NPY, but those in the median and posterior lobule neuropils were immunonegative for NPY. In the optic gland, almost all the CRF-IR varicose fibers were immunoreactive for NPY. Western blot analysis of the optic lobe and peduncle complex indicated that anti-CRF antiserum labeled approximate 16.4- and 14.6-kDa bands and that anti-NPY antiserum labeled an approximate 16.2-kDa band. CRF-IR and NPY-immunoreactive neurons in the optic lobe may participate in the modulation of visual information and those in the optic gland may be involved in the regulation of endocrine function.     

Genetic structure of Octopus vulgaris (Cephalopoda,Octopodidae) in the central Mediterranean Sea inferred from the mitochondrial COIII gene

The polymorphism of the mitochondrial gene cytochrome oxidase III was studied in the Mediterranean octopus, Octopus vulgaris Cuvier, 1797. A total of 202 specimens from seven sampling sites were analysed with the aim of elucidating patterns of genetic structure in the central Mediterranean Sea and to give an insight into the phylogeny of the Octopus genus. Phylogenetic analyses showed that individuals from the central Mediterranean belong to the O. vulgaris species whose limits should nevertheless be clarified. Concerning genetic structure, two high-frequency haplotypes were present in all locations. The overall genetic divergence (Φ_ST = 0.05, P < 0.05) indicated a significant genetic structuring in the study area and an AMOVA highlighted a significant break between western and eastern Mediterranean basins (Φ_CT = 0.094, P < 0.05). Possible explanations for the observed patterns of genetic structuring are discussed with reference to their relevance for fisheries management.     

Morphological and genetic description of Octopus insularis, a new cryptic species in the Octopus vulgaris complex (Cephalopoda: Octopodidae) from the tropical southwestern Atlantic

A medium-sized Octopus species is described based on materialcollected in shallow equatorial waters around the oceanic islandsof Fernando de Noronha Archipelago, Rocas Atoll, St Peter andSt Paul Archipelago and the mainland of northeastern Brazil.The new species, Octopus insularis, is described morphologically,and also characterized by the large mitochondrial subunit ribosomalRNA gene (mt 16S rDNA). The new species has relatively shortand stout arms, rugose reddish brown skin in preserved specimens,8 to 11 gill lamellae on the outer demibranchs, small ligula,characteristic symmetrical radula, spermatophore and beak, smalleggs and high fecundity (213,000 oocytes under 1.5 mm diameter).The habitats and skin patterns of living animals are brieflydescribed. The new species differs both morphologically andgenetically from Octopus vulgaris in the Mediterranean, Venezuelaand southern Brazil. (Received 10 November 2006; accepted 19 October 2007)     

Coccidian infection may explain the differences in the life history of octopus host populations

The prevalence of coccidian parasites in three Octopus tehuelchus populations from San Matías Gulf (Patagonia, Argentina) is compared. The prevalence was similar between sexes, but varied between seasons (being highest during cold months) and sites. Islote Lobos had the highest prevalence (42.7–100%) followed by San Antonio Bay (0–66%) and El Fuerte (0–24.5%). Octopuses under 27 mm of dorsal mantle length showed a low prevalence (less than 50%), which increased with size. We hypothesize that the high prevalence of parasites, which affect the three populations differentially, could account for the observed variability in life-span and growth, size–frequency distributions, reproduction and densities of O. tehuelchus populations.     

Prey selection and the functional response of sea stars (Asterias vulgaris Verrill) and rock crabs (Cancer irroratus Say) preying on juvenile sea scallops (Placopecten magellanicus (Gmelin)) and blue mussels (Mytilus edulis Linnaeus)

Predators in nature include an array of prey types in their diet, and often select certain types over others. We examined (i) prey selection by sea stars (Asterias vulgaris) and rock crabs (Cancer irroratus) when offered two prey types, juvenile sea scallops (Placopecten magellanicus) and blue mussels (Mytilus edulis), and (ii) the effect of prey density on predation, prey selection, and component behaviours. We quantified predation rates, behavioural components (proportion of time spent searching for prey, encounter probabilities) and various prey characteristics (shell strength, energy content per prey, handling time per prey) to identify mechanisms underlying predation patterns and to assess the contribution of active and passive prey selection to observed selection of prey. Sea stars strongly selected mussels over scallops, resulting from both active and passive selection. Active selection was associated with the probability of attack upon encounter; it was higher on mussels than on scallops. The probability of capture upon attack, associated with passive selection, was higher for mussels than for scallops, since mussels can not swim to escape predators. Sea stars consumed few scallops when mussels were present, and so did not have a functional response on scallops (the target prey). Rock crabs exhibited prey switching: they selected mussels when scallop density was very low, did not select a certain prey type when scallop density was intermediate, and selected scallops when scallop density was high relative to mussel density. The interplay between encounter rate (associated with passive selection) and probability of consumption upon capture (associated with both active and passive selection) explained observed selection by crabs. Scallops were encountered by crabs relatively more often and/or mussels less often than expected from random movements of animals at all scallop densities. However, the probability of consumption varied with scallop density: it was lower for scallops than mussels at low and intermediate scallop densities, but tended to be higher for scallops than mussels at high scallop densities. When mussels were absent, crabs did not have a functional response on scallops, but rather were at the plateau of the response. When mussels were present with scallops at relatively low density, crabs exhibited a type II functional response on scallops. Our results have implications for the provision of protective refuges for species of interest (i.e., scallops) released onto the sea bed, such as in population enhancement operations and bottom aquaculture.