Characterization of polychaetes inhabiting estuaries and inner bays by composition analysis of amino acids and lactate enantiomers

Abstract

In this study, we investigated the composition of free amino acids and lactate (Lac) in polychaetes in river estuaries and inner bays using chromatographic techniques. Both l-amino acids and d-amino acids (d-asparagine, d-alanine (d-Ala), d-serine, d-aspartic acid, and d-proline (d-Pro)) were detected, indicating that polychaetes contain some d-amino acids. Some polychaete species exhibited notable amino acid levels, such as glycine in Capitellidae sp. and Thelepus sp., d-Pro in Glycera sp., and β-Ala in Scoletoma nipponica and Scoletoma sp.. High d-Lac levels were detected in Tylorrhynchus osawai and Hediste diadroma, (691 and 797 μmol/100 g-wet, respectively), with the d-form exceeding 98%. T. osawai was dominant in the upper tidal-sensitive zone, wherein other organisms were less abundant because of low salinity (3–8 PSU). Seasonal differences in the concentrations of components in T. osawai were observed, particularly a significant increase in d-Lac in the reproductive period. Notably, the d-Lac concentrations of T. osawai were higher upstream than downstream. Thus, d-Lac might be involved in strategies underlying adaptations to low salinity and reproductive activity. These results suggest that both the d-form of Lac and amino acids may play certain physiological roles in the life of polychaetes.

Determination of Imidazole Dipeptides and Related Amino Acids in Natural Seafoods by Liquid Chromatography–Tandem Mass Spectrometry Using a Pre-Column Derivatization Reagent

“…In positive ion mode, the production of the m / z 91 fragment, which has previously been used to quantify amino acids in foods [ 26 ] and aquatic biological samples [ 27 ], was found to depend on the CE ( Figure 4 ). The CEs that most frequently produced the m / z 91 ion were −30 V for CIMa-Ala ( Figure 4 d) and CIMa-Tau ( Figure 4 f), −40 V for CIMa-His ( Figure 4 e), and −50 V for CIMa-Car ( Figure 4 a) and CIMa-Ans ( Figure 4 b).…”

“…The LC–MS/MS instrument, mobile phase, column, mobile phase composition, and mobile phase gradient were reported previously [ 26 , 27 ]. Briefly, a triple quadrupole LCMS-8040 mass spectrometer (Shimadzu, Kyoto, Japan) attached to an electrospray ionization interface was used, along with two pumps (LC-20AD), an autosampler (SIL-20AC), a column oven (CTO-20A), and PC software (LabSolutions ver.…”

“…Consequently, this derivatization reagent was successfully applied to determine not only the l - amino acid, but also the d- amino acid contents in various fermented foods, including miso [ 25 ] and black garlic [ 26 ]. In addition, its applicability was extended to the analysis of d -amino acids in aquatic invertebrates, specifically polychaetes [ 27 ], revealing large concentration differences across polychaete species.…”