Invertebrates peptides from

Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and byproducts, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed. 

ACE-inhibitory peptides from invertebrates such as crustaceans have been reported. The sequential hydrolysis of defatted Antarctic krill muscle via pepsin and trypsin resulted in an ACE-inhibitory extract. The active peptide isolated from the extract was found to be Lys-Leu-Lys-Phe-Val, showing an IC50 value of 30jiM (Kawamura et ah, 1992). The other crustacean, Acetes chinensis, used the protease from Bacillus sp. 

As antioxidant peptides are rarely present in marine invertebrates, they must be released from the parent protein by hydrolysis with enzymes. Various enzymes have been used to release peptides from muscle proteins. To date, different muscle proteins have been extracted, hydrolysed, and their antioxidant activities studied, which is among all invertebrate muscles the most similar to vertebrate skeletal muscle. Various studies have been conducted to investigate the antioxidant properties of hydrolysates or bioactive peptides from marine invertebrate sources like oysters... 

This suggests that products with bioactive peptides derived from marine invertebrates can meet the needs of marine organism-derived products due to health and/or religious reasons. From such a viewpoint, hydrolysates or bioactive peptides from marine invertebrates can be interesting sources of bioactivity peptides in the treatment of chronic diseases. 

Otero-Gonzalez, A. J., Magalhaes, B. S., Garcia-Villarino, M., Lopez-Abarrategui, C., Sousa, D. A., Dias, S. C., and Franco, O. L. (2010). Antimicrobial peptides from marine invertebrates as a new frontier for microbial infection control. FASEB ]. 24,1320-1334. 

Tincu, J. A. and Taylor, S. W. (2004). Antimicrobial peptides from marine invertebrates. Antimicrob. Agents Chemother. 48, 3645-3654. 

Sperstad, S. V., Haug, T., Blencke, H. M., Styrvol, . B., Li, C, and Stensvag, K. (2011). Antimicrobial peptides from marine invertebrates Challengers and perspectives in marine antimicrobial peptide discovery. Biotechnol. Adv. 29, 519-530. 

Cone snails, Conus spp., have been investigated because of their production of conotoxin peptides. From an evolutionary standpoint, the production of conotoxins is quite interesting due to their wide range of neurophysiological activities. The conotoxins are small peptides, 10-30 amino acids, with conformations constrained by multiple disulfide bonds that target a number of receptors in vertebrate and invertebrate nervous systems. Cone snails use these toxins to immobilize prey, which allows the relatively slow-moving cone snails to feed on fish and worms. The wide variety of conotoxins isolated and the hypervariability within peptide sequences has led some to hypothesize a combinatorial biosynthetic approach for the production of conotoxins.116117... 

The following protocols can be used for the isolation and structural characterization of any natural bioactive peptides from the immune system of invertebrates. The different procedures that will be detailed below refer to the identification and primary structure determination of the Drosophila immune-induced peptides (19,20,23,27,30) and of bioactive peptides from the immune system of other Diptera (17,21,24,31). These approaches were also successfully used for the discovery of bioactive peptides from crustaceans, arachnids, and mollusks. These methods should be considered as a guideline and not as the exact procedure to follow (see Note 3). The suggested procedures will be reported following the normal order of execution, (1) induction of the immune response by an experimental infection, (2) collection of the immunocompetent cells (hemocytes), tissues (epithelia, trachea, salivary glands, etc.)... 

Because of their well-recognized physicochemical properties (relatively high hydrophobicity, cationic character, and short length) reversed-phase, size-exclusion, and cation exchange chromatographies are particularly appropriate to purify bioactive peptides from the immune system of invertebrates. The sensitivity of HPLC, MS, Edman degradation, and liquid growth inhibition assays allow one to use from narrow (e.g., 2.1-mm internal diameter) down to micro-or nano-columns. 

A relevant set of not experimentally infected individuals (control) is required for differential analysis by MALDI-TOF-MS or RP-HPLC in order to discriminate between immune-induced molecules and constitutively present substances (19). This is a prerequisite when no in vitro assays are used to select the bioactive peptides from the immune system of the model invertebrate investigated. 

Bulet, P, Stocklin, R., and Menin, L. (2004) Anti-microbial peptides from invertebrates to vertebrates. Immunol. Rev. 198,169-184. 

Hancock, R.E., Brown, K.L., and Mookherjee, N. (2006) Host defence peptides from invertebrates—emerging antimicrobial strategies. Immunobiology 211(4), 315-322. 

The invertebrate peptides PCH (pigment-concentrating hormone 46) and AKH I (adipokinetic hormone 47) were the first neuropeptides from invertebrates to have their structure and synthesis described by L. Josefsson in 1983 94). 

Additional myotropic/inhibitory neuropeptide structures will be characterized on the basis of immunological similarity to vertebrate and invertebrate peptide structures, and also with the techniques of molecular biology. Two initial successes with those methods are discussed in this report (17,25). In addition, antibodies raised against FMRFamide were used to isolate and structurally characterize a nonapeptide containing C-terminal FMRFamide from head extracts of Drosophila (26). Subsequently, the gene that codes for this nonapeptide and eight other FMRFamide-related structures was isolated and sequenced (27,28). 

Cruz, L.J., Desantos, V., Zafaralla, G.C., Ramillo, C.A., Zeikus, R., Gray, W.R., and Olivera, B.M. (1987) Invertebrate vasopressin oxytocin homologs characterization of peptides from Conus geographus and Conus striatus venoms. J. Biol. Chem., 262, 15821-15824. 

Characterization of two crustin antimicrobial peptides from the freshwater crayfish Pacifastacus leniusculus, J Invertebr Pathol, 104,234-8. 

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