Metabolic rate and rates of protein turnover in food-deprived cuttlefish, Sepia officinalis (Linnaeus 1758)

To determine the metabolic response to food deprivation, cuttlefish (Sepia officinalis) juveniles were either fed, fasted (3 to 5 days food deprivation), or starved (12 days food deprivation). Fasting resulted in a decrease in triglyceride levels in the digestive gland, and after 12 days, these lipid reserves were essentially depleted. Oxygen consumption was decreased to 53% and NH4 excretion to 36% of the fed group following 3-5 days of food deprivation. Oxygen consumption remained low in the starved group, but NH4 excretion returned to the level recorded for fed animals during starvation. The fractional rate of protein synthesis of fasting animals decreased to 25% in both mantle and gill compared with fed animals and remained low in the mantle with the onset of starvation. In gill, however, protein synthesis rate increased to a level that was 45% of the fed group during starvation. In mantle, starvation led to an increase in cathepsin A-, B-, H-, and L-like enzyme activity and a 2.3-fold increase in polyubiquitin mRNA that suggested an increase in ubiquitin-proteasome activity. In gill, there was a transient increase in the polyubiquitin transcript levels in the transition from fed through fasted to the starved state and cathepsin A-, B-, H-, and L-like activity was lower in starved compared with fed animals. The response in gill appears more complex, as they better maintain rates of protein synthesis and show no evidence of enhanced protein breakdown through recognized catabolic processes

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

Food limitation is a common challenge for animals. Cephalopods are sensitive to starvation because of high metabolic rates and growth rates related to their "live fast, die young" life history. We investigated how enzymatic capacities of key metabolic pathways are modulated during starvation in the common cuttlefish (Sepia officinalis) to gain insight into the metabolic organization of cephalopods and their strategies for coping with food limitation. In particular, lipids have traditionally been considered unimportant fuels in cephalopods, yet, puzzlingly, many species (including cuttlefish) mobilize the lipid stores in their digestive gland during starvation. Using a comprehensive multi-tissue assay of enzymatic capacities for energy metabolism, we show that, during long-term starvation (12 days), glycolytic capacity for glucose use is decreased in cuttlefish tissues, while capacities for use of lipid-based fuels (fatty acids and ketone bodies) and amino acid fuels are retained or increased. Specifically, the capacity to use the ketone body acetoacetate as fuel is widespread across tissues and gill has a previously unrecognized capacity for fatty acid catabolism, albeit at low rates. The capacity for de novo glucose synthesis (gluconeogenesis), important for glucose homeostasis, likely is restricted to the digestive gland, contrary to previous reports of widespread gluconeogenesis among cephalopod tissues. Short-term starvation (3-5 days) had few effects on enzymatic capacities. Similar to vertebrates, lipid-based fuels, putatively mobilized from fat stores in the digestive gland, appear to be important energy sources for cephalopods, especially during starvation when glycolytic capacity is decreased perhaps to conserve available glucose

Respiration and nitrogen excretion by the squid Loligo forbesi

Respiration and nitrogen excretion rates of mature adult Loligo forbesi were investigated at the Roscoff Laboratory (North Brittany, France) during individual short-term incubation experiments in January 1986. The squids were in post-digestive condition and not actively swimming. Both oxygen uptake and nitrogen excretion are continuous processes. The metabolic rates of this active nektonic species (145 ml kg-1 h-1 oxygen uptake, 18.56 μg g-1 h-1 ammonia excretion) are distinctly higher than those of benthic cephalopods. Proteins constitute the main metabolic substrate for energetic needs. Besides ammonia, urea is also continuously released, in amounts ranging from 5 to 16% of ammonia-excretion values

FIGURE 1 in A new genus and species of sepiolid squid from the waters around Tonga in the central South Pacific (Mollusca: Cephalopoda: Sepiolidae)

FIGURE 1. Choneteuthis tongaensis gen. et sp. nov. Photographs of holotype. A: dorsal view of whole animal; B: ventral view of whole animal; C: left lateral view of whole animal; D: ventral view of arm region.Published as part of Lu, C. C. & Boucher-Rodoni, R., 2006, A new genus and species of sepiolid squid from the waters around Tonga in the central South Pacific (Mollusca: Cephalopoda: Sepiolidae), pp. 37-51 in Zootaxa 1310 on page 46, DOI: 10.5281/zenodo.17385

Choneteuthis Lu & Boucher-Rodoni, 2006, gen. nov.

Genus Choneteuthis gen. nov. Etymology: The generic epithet is derived from the Greek word for funnel. It refers to the long, tubular, and exposed funnel of the animal, a feature not seen in any other sepiolid. Diagnosis: Funnel long, tubular, not covered by mantle, web uniting arms shallow, a large, round photophore present on ink sac, colored ventral shield present, anterodorsal margin of mantle and head not fused, well developed nuchal cartilage present, gladius present, hectocotylized arms absent. Type species: Choneteuthis tongaensis sp. nov.Published as part of Lu, C. C. & Boucher-Rodoni, R., 2006, A new genus and species of sepiolid squid from the waters around Tonga in the central South Pacific (Mollusca: Cephalopoda: Sepiolidae), pp. 37-51 in Zootaxa 1310 on pages 38-39, DOI: 10.5281/zenodo.17385

A revision of the deep-water octopus genus Scaeurgus (Cephalopoda : Octopodidae) with description of three new species from the southwest Pacific Ocean

Deep-water trawl surveys on seamounts around New Caledonia yielded 62 specimens of the little-known genus, Scaeurgus. Members of this genus of octopuses typically occur at depths of 200-500 m in temperate and tropical latitudes worldwide. Prior to this study, Scaeurgus was considered to contain one to two species. The new material from New Caledonia contained a surprising diversity of Scaeurgus species from a small area: three distinct new species are described and limited material of a further two taxa is reported. A pygmy member of this genus is reported for the first time. Distributions of these new taxa are consistent with reports of high endemism on the seamount systems in this region. Fifty-eight of the 62 specimens were collected from seamounts, with four of the five taxa unique to a single seamount

Comparative bioaccumulation of trace elements between Nautilus pompilius and Nautilus macromphalus (Cephalopoda: Nautiloidea) from Vanuatu and New Caledonia

The concentrations of 16 trace elements were investigated and compared for the first time in the digestive and excreting tissues of two Nautilus species (Cephalopoda: Nautiloidea) from two geologically contrasted areas: (1) N. macromphalus from New Caledonia, a region characterized by its richness in nickel ores and its lack of tectonic activities and (2) N. pompilius from the Vanuatu archipelago showing high volcanic and tectonic activities. In both Nautilus species, results clearly highlighted that the digestive gland played a key role in the bioaccumulation and storage of Ag, Cd, Ce, Co, Cu, Fe, La, Nd, V, and Zn whereas As, Cr, Mn, Ni, Pb, and Se were accumulated in a greater extent in the excreting tissues (i.e. pericardial and renal appendages). Despite contrasting environments, no significant difference (p<0.05) was found between the two Nautilus species in the concentrations of most of the essential and non-essential elements, including Ni and associated metals in Ni ores (i.e. Co and Mn). As nautilus lives on the outer shelf of barrier reefs, these results strongly support the hypothesis that the New Caledonian lagoon traps the major amount of the trace elements derived from natural erosion and the intense mining activities conducted on land. In contrast, the concentrations of the rare earth elements (Ce, La, and Nd) were significantly higher in N. pompilius than in N. macromphalus, probably as a result of the local enrichment of Vanuatu waters by specific environmental processes, such as volcanism or upwelling. © 2008 Elsevier Inc. All rights reserved

A phylogenetic study of the squid family Onychoteuthidae (Cephalopoda: Oegopsida)

The oegopsid squid family Onychoteuthidae presently comprises six genera (Moroteuthis, Onychoteuthis, Ancistroteuthis, Kondakovia, Onykia and Chaunoteuthis) but the status of some of these is still uncertain. An interdisciplinary study was undertaken to clarify the phylogenetic relationships, which included a morphological approach (morphometric analysis), and a molecular study of a mitochondrial gene portion (l-rRNA gene, 16S). The morphometric analysis identified two groups, one including some Onychoteuthis and some Moroteuthis knipovitchi, and another including the remaining genera or species. At the intrageneric level, M. knipovitchi appears to be separated from the other species of the genus; M. robusta is closely related to M. ingens and M. pacifica. Morphometric analysis confirmed that Kondakovia longimana is different from M. ingens. Likewise, Onychoteuthis was clearly separated from the other genera, but there is neither geographical grouping nor morphometric differentiation of the Onychoteuthis species with the parameters measured. Some specimens were apparently intermediate between the Onychoteuthis and Ancistroteuthis groups. On a molecular basis, the Onychoteuthidae appeared to be monophyletic. Monophyly of the genus Moroteuthis (four species studied) was not strongly supported: M. knipovitchi was distinct from the others. The molecular analysis showed three Hawaiian species, Onychoteuthis compacta, O. sp. B and O. sp. C, to be closely related. The gene sequence for the newly created species of Onykia is clearly different from all the others, indicating that it is a true species