Invertebrates conjugation

A limited amount of information is available on the formation of metabolites of aromatic hydrocarbons in aquatic invertebrates however, some studies have elucidated the structures of conjugated and non-conjugated derivatives produced in these organisms. The bioconversion of naphthalene by the spider crab (Maia squinado) has been studied by Corner et al. (45). These workers identified... 

Xenobiotic carboxylic acids can be excreted as amino acid conjugates, where the COOH grot ) forms an amide bond with the -NHg group of an amino acid. In mammals, the aminn acid most commonly used for conjugation is glycine. This pathway has been studied in vitro and In vivo in several fish species and a marine Invertebrate. 

Judging from its broad distribution among plants and invertebrates and its relatively rare occurrence in mammals, glucosylation appears to have evolved as a conjugation mechanism prior to glucu-ronidation. Smith ( 7), speculating on why evolution might have... 

Sulfate formation has also been demonstrated in a variety of other Invertebrates including spiders, scorpions and ticks (7), although the arachnids appear to possess no alternative glycosTde mechanism for phenol conjugation. 

Nonextractable radioactivity in invertebrate and fish tissues likely represents covalent conjugates (i.e., macromolecular bound residues) [6,7], However, neither the biological half-life nor the chemical nature of nonextractable transformation products in invertebrates and fish has been investigated to date. Formation of covalent bonds with proteins in mammalian systems has been reported [28-30], Investigations on the biotransformation of other explosives or related products in aquatic animals were not found in the available literature. 

M. expansa, H. diminuta and F. hepatica failed to form hippurate, the glycine conjugate of benzoic acid (8), although small amounts of this product were detected in M. benedeni (60). Given that several other amino acids besides glycine can often serve as acyl acceptors particularly in invertebrate species (3), additional studies are needed before concluding that amino acid conjugation is not a pathway of parasite xenobiotic metabolism. 

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