Finding strategies to use the swim bladder of farmed totoaba (Totoaba macdonaldi) is of the utmost need to reduce waste. Fish swim bladders are rich in collagen; hence, extracting collagen is a promising alternative with benefits for aquaculture of totoaba and the environment. The elemental biochemical composition of totoaba swim bladders, including their proximate and amino acid compositions, was determined. Pepsin-soluble collagen (PSC) was used to extract collagen from swim bladders, and its characteristics were analyzed. Alcalase and papain were used for the preparation of collagen hydrolysates. Swim bladders contained 95% protein, 2.4% fat, and 0.8% ash (on a dry basis). The essential amino acid content was low, but the functional amino acid content was high. The PSC yield was high, at 68% (dry weight). The amino acid composition profile, electrophoretic pattern, and structural integrity analyses of the isolated collagen suggested it is a typical type-I collagen with high purity. The denaturalization temperature was 32.5 °C, probably attributable to the imino acid content (205 residues/1000 residues). Papain-hydrolysates (≤3 kDa) of this collagen exhibited higher radical scavenging activity than Alcalase-hydrolysates. The swim bladder from the farmed totoaba could be an ideal source to produce high-quality type I collagen and may be considered an alternative to conventional collagen sources or bioactive peptides.

Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3kDa leading to a metabolic phase (>3kDa) and a neurotoxic fraction (<3kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

Low-molecular-weight peptides derived from the digestion of body wall proteins in some sea cucumber species have wound-healing and health-promoting properties, but their potency varies widely by species, growth environment, age, and season. For the first time, small peptide (1–3 kDa) fractions have been isolated from the whole-body wall of the sea cucumber Isostichopus badionotus and its constituent collagen and tested for wound healing capacity in vitro. Ultrafiltered digests (1–3 kDa) of the pure collagen, as well as 1–3 kDa digests of the whole-body wall, had potent antioxidant activities and promoted rapid wound healing in a keratinocyte scratch wound assay. Gene expression studies suggested that the wound-healing actions of the individual collagen and body wall 1–3 kDa fractions differed significantly. Low-molecular-weight peptides derived from I. badionotus collagen did promote wound healing in vitro; however, their efficacy may have been modulated by additional factors produced during body wall or collagen digestion. These findings need to be confirmed in vivo.

Low-molecular-weight peptides derived by digestion of body wall proteins from some sea cucumber species have wound-healing and health-promoting properties. Sea cucumber body composition varies widely by species, growth environment, age and season, so it is unknown if all species contain the requisite bioactive peptides. For the first time, small peptide (1-3 kDa) fractions have been isolated from the whole-body wall of the sea cucumber Isostichopus badionotus and its constituent collagen, and tested for wound healing capacity in vitro. The body wall comprised around 50% collagen, whose composition and structure were like, but not identical to, other sea cucumber collagens. Ultrafiltered digests (1-3 kDa) of the pure collagen and a further purified fraction of it, as well as a 1-3 kDa digest of whole-body wall, had potent antioxidant activities and promoted rapid wound healing in a keratinocyte scratch wound assay. Gene expression studies suggested that the wound-healing actions of the individual 1-3 kDa fractions differed significantly. Low-molecular-weight peptides derived from I. badionotus collagen did promote wound healing in vitro, however, their efficacy may have been modulated by additional factors produced during body wall or collagen digestion.