Metabolism of Pyruvate in Postmortem Adductor Muscle of the Sea Scallop (Placopecten magellanicus) During Iced Storage

1975 ◽  
Vol 32 (8) ◽  
pp. 1329-1337 ◽  
Author(s):  
M. Sakaguchi ◽  
Doris Fraser Hiltz ◽  
W. J. Dyer
Keyword(s):  
Ion Exchange ◽  
Metabolic Pathways ◽  
Storage Period ◽  
Adductor Muscle ◽  
Exchange Chromatography ◽  
Placopecten Magellanicus ◽  
Metabolic Pattern ◽  
Sea Scallop ◽  
Reductive Condensation ◽  
Iced Storage

Glycolytic metabolic pathways in postmortem adductor muscle of the sea scallop (Placopecten magellanicus) during iced storage were studied by means of 14C-pyruvate injected into the muscles. Ion-exchange fractionation of perchloric acid extracts of muscle into cationic, anionic, and neutral components showed that the radioactivity derived from 14C-pyruvate was rapidly incorporated into the cationic fraction during the postmortem storage period. Subsequent ion-exchange chromatography revealed that most of the radioactivity in the cationic fraction was distributed among three major peaks, whose components were identified by paper chromatography as (Peak I) alanine, (Peak II) α-amino-n-butyric acid and an unidentified compound, and (Peak III) octopine. These findings indicate that the disposition of pyruvate in postmortem scallop muscle is mainly via two pathways: transamination to amino acids, and reductive condensation with arginine to octopine. This metabolic pattern in muscles injected immediately after shucking (0-day series) did not differ significantly from that in muscles injected after preliminary storage of the shucked meats for 4 days in ice (4-day series).

Octopine in Postmortem Adductor Muscle of the Sea Scallop (Placopecten magellanicus)

1971 ◽  
Vol 28 (6) ◽  
pp. 869-874 ◽  
Author(s):  
Doris Fraser Hiltz ◽  
W. J. Dyer
Keyword(s):  
Storage Period ◽  
Lactic Dehydrogenase ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Reductive Condensation ◽  
Nucleotide Degradation ◽  
Octopine Dehydrogenase ◽  
Iced Storage ◽  
Early Postmortem

Study of the rate and extent of octopine formation in ice-stored sea scallop meat (Placopecten magellanicus) confirms that it, rather than lactate, is a principal end product of carbohydrate metabolism in this species. Little or no octopine is detectable in fresh muscle dissected from live scallops, but on subsequent iced storage octopine accumulates, with reciprocal decrease in arginine, to maximum levels of about 1% in 6–10 days. An active octopine dehydrogenase, catalyzing the reductive condensation of arginine and pyruvate, was present, and lactic dehydrogenase activity was absent. Octopine accumulation occurs concomitantly with nucleotide degradation (dephosphorylation of adenosine 5′-triphosphate (ATP)). Its formation is linearly related to decline in muscle pH.Octopine production had usually attained its maximum considerably before the point of inedibility was reached; hence, the use of octopine content as an index of quality in scallop meats seems limited to the early postmortem storage period, as confirmation of freshness.

Accumulation of domoic acid by the sea scallop (Placopecten magellanicus) fed cultured cells of toxic Pseudo-nitzschia multiseries

1997 ◽  
Vol 54 (4) ◽  
pp. 907-913 ◽  
Author(s):  
D J Douglas ◽  
E R Kenchington ◽  
C J Bird ◽  
R Pocklington ◽  
B Bradford ◽  
...  
Keyword(s):  
Digestive Gland ◽  
Domoic Acid ◽  
Cultured Cells ◽  
Exposure Period ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Bivalve Molluscs ◽  
Destructive Sampling ◽  
Sea Scallop ◽  
Sea Scallops

Sea scallops (Placopecten magellanicus) were fed Pseudo-nitzschia multiseries (formerly P. pungens f. multiseries, Nitzschia pungens f. multiseries) cells of high domoic acid (DA) content (4.0-6.7 pg DA cdot cell-1) for 22 days, followed by 14 days of feeding with nontoxic microalgae. DA was incorporated within 24 h by the scallops, with increased uptake after 6 days, and was concentrated in tissues in the following order: digestive gland >> remaining soft tissue >> adductor muscle. A maximum DA concentration of 3108 mu g cdot g-1 was recorded in the digestive gland, approximately 150 times the regulatory limit (20 mu g DA cdot g-1) and among the highest levels observed in bivalve molluscs; however, only trace amounts, 0.7-1.5 mu g cdot g-1, were found concomitantly in the adductor muscle. At the end of the exposure period, 50.9% of the DA that had been supplied to the scallops had been incorporated into the tissues. Concentrations in the digestive gland 14 days after termination of the toxic diet remained high, 752 mu g DA cdot g-1. Throughout the experiment, there was no sign of illness or mortality attributable to high DA loading, although the destructive sampling of animals did not allow us to assess the effects of the toxin in the longer term.

Occurrence of Trigonelline (N-Methyl Nicotinic Acid) in the Adductor Muscle of a Lamellibranch, the Sea Scallop (Placopecten magellanicus)

1970 ◽  
Vol 27 (3) ◽  
pp. 604-606 ◽  
Author(s):  
Doris Fraser Hiltz
Keyword(s):  
Thin Layer ◽  
Nicotinic Acid ◽  
Column Chromatography ◽  
Spectral Properties ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Linear Gradient ◽  
Sea Scallop

Trigonelline, associated with its isomer homarine, has been found in amounts ranging from 0.7 to 1.3 μmoles/g in scallop adductor muscle. Separation of the two betaines was achieved by column chromatography on a cation-exchange resin, using a linear gradient of 2 N HCl into H2O. Identification of trigonelline was based on spectral properties and on behavior in thin-layer, paper, and column chromatography.

Hexose Monophosphate Accumulation and Related Metabolic Changes in Unfrozen and Thawed Adductor Muscle of the Sea Scallop (Placopecten magellanicus)

1973 ◽  
Vol 30 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Doris Fraser Hiltz ◽  
W. J. Dyer
Keyword(s):  
Adductor Muscle ◽  
Metabolic Changes ◽  
Hexose Monophosphate ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Chill Storage ◽  
Quick Freezing ◽  
Wide Range ◽  
Maillard Browning ◽  
Index Of Quality

The hexose monophosphates (glucose-6-phosphate (G6P), fructose-6-phosphate, and glucose-1-phosphate) accumulate postmortem in scallop adductor muscle (meats) during chill storage, increasing from only traces at death to levels totalling about 10 μmole/g after 8–10 days. In both unfrozen and thawed meats, G6P accounted consistently for 80–85% of the total hexose monophosphate, over a wide range of actual concentrations. Quick freezing at any time postmortem did not affect the concentrations of hexose monophosphates or related metabolic constituents. Thawing of the prerigor-frozen muscle, however, either slowly or rapidly, resulted in considerable G6P formation, and accelerated markedly the subsequent rate and extent of G6P production. The exceptionally high levels (− 20 μmole/g) reached in the thawed meats after 1–2 days at 5 C are implicated in the development of burned flavors, odors, and discolorations (i.e. Maillard browning reactions) observed in these thawed meats when cooked. While thawing of the prerigor-frozen muscle led to some hypoxanthine (Hx) and octopine formation, the subsequent rate of Hx accumulation at 5 C was three times faster in the thawed meats than in unfrozen meats. In meats frozen postrigor, thawing resulted in negligible change in concentrations of the metabolites; subsequent patterns of change during storage differed little from those in unfrozen muscle, although Hx accumulation was more rapid. Hx content showed potential as an index of quality in thawed scallop muscle.

Paralytic Shellfish Poison in Sea Scallops (Placopecten magellanicus) in the West Atlantic

1983 ◽  
Vol 40 (3) ◽  
pp. 313-318 ◽  
Author(s):  
G. S. Jamieson ◽  
R. A. Chandler
Keyword(s):  
Adductor Muscle ◽  
Bay Of Fundy ◽  
Georges Bank ◽  
Placopecten Magellanicus ◽  
Eastern Canada ◽  
The West ◽  
Monthly Basis ◽  
Sea Scallop ◽  
Paralytic Shellfish ◽  
Sea Scallops

Levels of Gonyaulax excavata toxin in sea scallop (Placopecten magellanicus) tissues were monitored in eastern Canada on a monthly basis between 1977 and 1981. All tissues but the adductor muscle were found to be highly toxic in Bay of Fundy scallops, with negligible toxicity observed in scallops from Georges Bank, the outer Scotian Shelf, and Northumberland Strait scallops. Level of Bay of Fundy toxicity was much higher than previously observed (maximum digestive gland toxicity: 150 000 μg/100 g in March 1978), and recent average monthly toxicity for Bay of Fundy scallop roe ranged from 184 to 286 μg/100 g. Considerable fluctuation in toxicity can occur between adjacent months, and peak toxicities in sea scallops occur during fail and winter months. Scallop roe fisheries should be permitted to be established for scallops fished from the northern part of Georges Bank and Northumberland Strait. However, a closed zone for scallop roe should be established in the Bay of Fundy and adjacent Scotian Shelf.Key words: scallop, PSP, Gonyaulax, Placopecten, mollusk

Accelerated Nucleotide Degradation and Glycolysis During Warming to and Subsequent Storage at −5 C of Prerigor, Quick-frozen Adductor Muscle of the Sea Scallop (Placopecten magellanicus)

1974 ◽  
Vol 31 (7) ◽  
pp. 1181-1187 ◽  
Author(s):  
Doris Fraser Hiltz ◽  
Lucy J. Bishop ◽  
W. J. Dyer
Keyword(s):  
Metabolic Activity ◽  
Freezing Point ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Effects Of Temperature ◽  
Nucleotide Degradation ◽  
Subsequent Storage ◽  
Commercial Distribution

During slow warming of prerigor, quick-frozen scallop meats from −26 to −5 C, arginine phosphate and ATP were split rapidly between −8 and −6 C (in about 2 h), resulting in the accumulation of some ADP, and of large amounts of AMP, equivalent to 85% of the ATP originally present. Concomitant activation of glycolysis caused a substantial increase in fructose 1,6-diphosphate (FDP) concentrations, and smaller increases in the hexose monophosphates (HMP) and in octopine. The relatively low freezing point of prerigor scallop muscle, found to be −1.4 C, may be implicated in the stimulation of metabolic activity at a temperature as low as −5 C; the rates were faster than at 0 C and occurred at subfreezing temperatures considerably lower than those for most fish muscle.With continued storage at −5, FDP decreased as HMP concentrations rose sharply to maximum levels at 24 h; octopine accumulation was slower, attaining maximum concentrations at 5 wk. Rates of AMP degradation and of hypoxanthine accumulation were similar to those in unfrozen, iced scallop muscle, indicative of differential effects of temperature on the various metabolic enzymes.Because of the extensive metabolic activity in scallop muscle at temperatures near −5, the optimal quality of prerigor quick-frozen meats may be affected adversely by current commercial distribution and marketing practices where warming to temperatures just below the freezing point may be encountered.

Cadmium in Sea Scallop (Placopecten magellanicus) Tissues from Clean and Contaminated Areas

1987 ◽  
Vol 44 (1) ◽  
pp. 91-98 ◽  
Author(s):  
J. F. Uthe ◽  
C. L. Chou
Keyword(s):  
Digestive Gland ◽  
Soft Tissues ◽  
Shell Height ◽  
Cadmium Concentration ◽  
Predictor Variable ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Tissue Concentrations ◽  
Sea Scallop ◽  
Sea Scallops

Over 90% of the total cadmium in the soft tissues of sea scallops (Placopecten magellanicus) was in the digestive gland with less than 1% in the adductor muscle. The amount of cadmium in the digestive gland was significantly related to shell height. Shell height was superior to age as an independent (predictor) variable due to difficulties in ageing scallops. Based on these relationships, scallops of approximately 100 mm shell height were selected to study interregional differences. Neither cadmium concentration nor burden could be used to identify contaminated areas. The ratio of digestive gland cadmium to that in the adductor muscle was lowest for scallops from Chaleur Bay, which had received substantial anthropogenic cadmium input, and for scallops that had been starved for approximately 14 mo. We suggest that the high tissue cadmium levels in scallops from Georges Bank and Browns Bank are not due to contamination from anthropogenic or natural sources but rather reflect feeding and the nutritional inadequacy of the diets. Conversely, the high levels of cadmium input to Chaleur Bay were not reflected in high tissue concentrations or burdens in scallops.

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