Free amino acid concentrations in Mytilus edulis L. From different locations in the southwestern part of the netherlands: Their possible significance as a biochemical stress indicator

doi:10.1016/0300-9629(89)90058-3

Comparative Biochemistry and Physiology Part A: Physiology

Volume 93, Issue 2, 1989, Pages 413-417

Comparative Biochemi...

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Abstract

1.
1. During an annual cycle, concentrations of free amino acids were determined in mussels, Mytilus edulis L., collected monthly from 10 different locations in the Delta area (southwest part of the Netherlands).
2.
2. The applicability of suggested biochemical stress indices, i.e. the ratio of the taurine/glycine concentrations and the sum of the threonine and serine concentrations, was investigated.
3.
3. It is shown that, due to large seasonal and environmental variations (reproduction, salinity etc.), these stress indices should be used with much care.

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P.A Gabbott
Developmental and seasonal metabolic activities in marine molluscs
H.P Jeffries
A stress syndrome in the hard clam, Mercenaria mercenaria
J. Invertebr. Pathol.
(1972)
D.I Zandee et al.
Seasonal changes in biochemical composition of Mytilus edulis L. with reference to energy metabolism and gametogenesis
Neth. J. Sea Res.
(1980)
W Zurburg et al.
The influence of seasonal changes on energy metabolism in Mytilus edulis L. II. Organ specificity
H Hummel et al.
The annual cycle of glycogen in estuarine benthic animals
Hydrobiol. Bull.
(1988)

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Cited by (9)

Seasonal variability of free amino acids in two marine bivalves, Macoma balthica and Mytilus spp., in relation to environmental and physiological factors
2007, Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
The seasonal variability of the intracellular free amino acid (FAA) concentration was studied in 5 Macoma balthica populations and 7 Mytilus spp. populations along their European distribution. Because of the well known physiological role of FAA as organic osmolytes for salinity induced cell volume regulation in marine osmoconformers, FAA variations were compared in bivalve populations that were exposed to high vs. low intraannual salinity fluctuations. In general, seasonal FAA variations were more pronounced in M. balthica than in Mytilus spp. In both bivalve taxa from different locations in the Baltic Sea, highest FAA concentrations were found in autumn and winter and low FAA concentrations were measured in summer. Seasonal patterns were less pronounced in both taxa at locations with constant salinity conditions. In contrast to Baltic Sea populations, Atlantic and Mediterranean bivalves showed high FAA concentrations in summer and low values in winter, regardless of seasonal salinity fluctuations. Significant seasonal FAA variations at locations with constant salinity conditions showed that salinity appeared not to be the main factor in determining FAA concentrations. The seasonal patterns of the main FAA pool components, i.e. alanine, glycine and taurine, are discussed in the context of seasonal variations in environmental factors (salinity, temperature) and physiological state (glycogen content, reproductive stage).
Free amino acid composition in juveniles of Mytilus galloprovincialis: Spatial variability after Prestige oil spill
2006, Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Citation Excerpt :
Taurine, glycine and alanine are the most representative amino acids in volume regulation of bivalves (Livingstone et al., 1979). FAA also take part in different energy-yielding metabolic pathways as substrates, constituents of proteins, enzymes and hormones and certain amino acids are also involved in reproduction and development (Livingstone, 1985; Zurburg et al., 1989). Therefore, FAA represent high amounts in tissues of marine invertebrates (Bishop et al., 1983).
Composition of free amino acids (FAA) in juveniles of Mytilus galloprovincialis was analysed along a large geographical coastline area in Galicia (NW Spain). Individuals were sampled in February 2003, three months after the Prestige oil spill. Pollution values at sampling time were reported as polycyclic aromatic hydrocarbons (PAHs) concentrations in soft tissues of individuals and varied between the highest amount observed in Carrumeiro mussels (502 ng/g dw) and the lowest in Pindo mussels (196 ng/g dw), both locations being close to each other in the centre of the geographical area under study. Pollution values in the other populations varied within the range of 241–347 ng/g dw. Total free amino acids (TFAA) were highest in Aguiño–Pindo–Carrumeiro juveniles at the centre of the Coastline area studied (420–462 μmol/g dw) as compared to the other populations at North and South of Galicia (312–347 μmol/g dw). TFAA results were based on the variability observed in protein free amino acids (PFAA μmol/g dw) among populations (214–249 μmol/g dw for Aguiño–Pindo–Carrumeiro mussels and 98–149 μmol/g dw for the other populations) whereas non-protein free amino acids (NPFAA) taurine and ornithine did not show any significant spatial pattern of variation. Glycine and alanine represented the most abundant PFAA (16–29% and 2.7–11.9% of TPFAA, respectively) and significant correlations between PFAA and both the protein content of soft tissues (r = − 0.82) and the condition index of juveniles (r = 0.86) were observed. No significant relationships were detected, however, between pollution values in soft tissues as PAHs and FAA profiles with the exception of alanine concentrations as percentage of TFAA (r = 0.88; P < 0.01). The latter seemed to be an “all or nothing” effect likely due to the influence of other abiotic factors at one of the sampling sites. Such relationship was found not significant when the outlier represented by Carrumeiro mussels was removed from the analysis. The most abundant free amino acid taurine (43.2–68.5%TFAA) followed an inverse variability of that of glycine and by extension of the group PFAA most likely as a compensatory decrease in mussel populations with low protein content (and high condition index). Accordingly, taurine:glycine (t:g) ratio varied between 1 and 2 in most mussel populations but increased up to 3.2–4.2 in Miranda and Bueu mussels at both ends of the geographical interval studied with a corresponding PAHs concentrations of 261 and 304 ng/g dw, respectively. These mussel populations with the highest t:g ratios were characterised by the lowest PFAA contents (below 40%) and condition index values (below 10%). Results of the present study established a significant link between energetic status of growing juveniles and FAA concentrations in environments with different pollution degrees. Variability of the free amino acids profiles in soft tissues were related to endogenous factors of juveniles (protein content, condition index) whereas no relationship with contamination values could be observed. The utility of t:g ratio as general condition factor for M. galloprovincialis is also corroborated for in situ growing juveniles.
Free amino acids in the clam Macoma balthica L. (Bivalvia, Mollusca) from brackish waters of the southern Baltic Sea
2003, Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Fourteen acidic and neutral free amino acids (FAA) were investigated in soft tissue of Macoma balthica from different depth zones of the Gulf of Gdansk (Baltic Sea) over a full seasonal cycle. The dry weight of the bivalves and physico-chemical parameters of overlying bottom water and surface sediments were measured simultaneously at each site. In the brackish waters of the Baltic, the main pool of FAA is composed of Ala, Gln, Arg, Gly and Orn which represent approximately 80% of the total. Compared to the full saline environments, the composition of FAA in the clams from the Baltic differs substantially. The differences can be attributed to the lower salinity of the Baltic. In the Baltic, Gly appears to play a most important role in regulating intracellular osmolarity in the clams, a function performed primarily by Tau in Atlantic and North Sea populations. Spatio-temporal variations of the FAA are affected by biotic and environmental parameters; their respective influence differs with the amino acids. The concentration of Arg depends on its uptake from the external medium. However, its level might be temporarily modified by stress-induced metabolic transformation (e.g. hydrolysis to Orn) caused by changes in the ambient environment. The concentration of Ala increases with depth, probably because of physiological adaptations of the animal to diminishing oxygen concentration through anaerobic glucose catabolism. Biosynthesis of Ala, similarly to Gln, in the shallower zone is generally related to the physiological state of an organism. The concentration of Gly is most likely regulated by internal mechanisms driven by gonadal development and reproduction.
Haemolymph and mantle fluid ammonia and ninhydrin positive substances variations in salinity-challenged mussels (Mytilus edulis L.)
1997, Journal of Experimental Marine Biology and Ecology
Ambient salinity change-induced variability of ammonia efflux rates, concentrations of ninhydrin positive substances (NPS) and dissolved ammonia (DA) in the haemolymph and mantle cavity fluid of Mytilus edulis were examined. Hypo-osmotic challenges evoked rapid (< 1 h) increases of DA efflux rates, to levels which persisted for the 4 h exposure period, and concomitant increases in haemolymph and mantle fluid NPS and DA levels. Exposure to hyper-osmotic media induced decreased DA efflux rates (cf. normal seawater levels in all cases). Such results suggest that intertidal M. edulis, which may normally experience rapid salinity changes, can make rapid adjustments to such osmotic stresses. Haemolymph hypoglycaemia (cf. control group) accompanied all salinity changes which suggests increased glucose utilisation occurs during the initial adjustments to external media salinity changes.
Free amino acids as a biochemical indicator of stress in the estuarine bivalve Macoma balthica
1996, Science of the Total Environment
The use of free amino acids (FAA) as a stress indicator was assessed during a copper exposure experiment for specimens of the estuarine bivalve M. balthica from a geographical gradient extending from the Netherlands to its most southern limit of distribution in the Gironde, France. Changes in FAA were significant. A higher alanine content at the start of the experiment coincided with a lower mortality-rate during copper exposure. During copper exposure the tissue concentrations of alanine increased. It is concluded that especially the concentrations of alanine, and to a lesser degree the taurine/glycine ( $T G$ ) ratio, can be used as stress-indicators for M. balthica. Animals near the southern limit of their distribution showed the strongest deviations from average values. The age of the animals (2–7 years) had no influence on results.
Evaluation of free amino acids as a biochemical indicator of metal pollution
1994, Marine Environmental Research
Mussels from the Fal estuary, SW England, were used to assess the applicability of free amino acids as a biochemical stress-index for metal pollution. Copper, and not salinity or zinc, was the main agent affecting the amounts and composition of the free amino acids. The use of the serine + threonine sum as an indicator of stress was highly questionable. The taurine/glycine ratio could only be used at concentrations of copper ≥ 20 μg liter⁻¹, where the ratio was increased. At lower copper concentrations the taurine/glycine ratio did not show a relationship with copper; at higher copper concentrations the mussels died. The mussels seemed to show an ‘all or nothing’ effect, i.e. the ‘window’ between tolerable and lethal levels for copper was small.

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Comparative Biochemistry and Physiology Part A: Physiology

Abstract

References (11)

Developmental and seasonal metabolic activities in marine molluscs

A stress syndrome in the hard clam, Mercenaria mercenaria

J. Invertebr. Pathol.

Seasonal changes in biochemical composition of Mytilus edulis L. with reference to energy metabolism and gametogenesis

Neth. J. Sea Res.

The influence of seasonal changes on energy metabolism in Mytilus edulis L. II. Organ specificity

The annual cycle of glycogen in estuarine benthic animals

Hydrobiol. Bull.

Cited by (9)

Seasonal variability of free amino acids in two marine bivalves, Macoma balthica and Mytilus spp., in relation to environmental and physiological factors

Free amino acid composition in juveniles of Mytilus galloprovincialis: Spatial variability after Prestige oil spill

Free amino acids in the clam Macoma balthica L. (Bivalvia, Mollusca) from brackish waters of the southern Baltic Sea

Haemolymph and mantle fluid ammonia and ninhydrin positive substances variations in salinity-challenged mussels (Mytilus edulis L.)

Free amino acids as a biochemical indicator of stress in the estuarine bivalve Macoma balthica

Evaluation of free amino acids as a biochemical indicator of metal pollution