William V. Allen

Changes in the fatty acid composition of steelhead trout, Salmo gairdnerii Richardson, associated with parr-smolt transformation.

Fatty acids from the several lipid classes of selected steelhead trout (Salmo gairdnerii) parr and smolt tissues, previously separated by thin-layer chromatography, were analyzed by gas-liquid chromatography. The fatty acid composition of the parr was markedly different from that of the smolt; the former being characterized by relatively low amounts of polyunsaturated fatty acids and relatively high amounts of linoleic acid, much like the typical freshwater lipid pattern. The fatty acid composition of the smolt was characterized by large proportions of long-chain polyunsaturated fatty acids. Generally, the fatty acid composition of the smolt resembled the typical seawater lipid pattern. The change in fatty acid composition of the smolt is anticipatory to seawater entry and is independent of diet and water temperature. These alterations suggest that the assumption of a polyunsaturated lipid pattern during parr-smolt transformation (smoltification) is preadaptive to seawater entry.

The essential amino acid requirements of the red abalone, Haliotis rufescens

Abstract 1. 1. Three juvenile specimens of the red abalone, Haliotis rufescens , were each injected with (U- 14 C) glucose. During an incubation period of 71–96 hr the radioactivity of the respiratory carbon dioxide and incubating sea water was monitored. 2. 2. Amino acid compositions of whole body protein were determined. 3. 3. The radioactivity of individual amino acids was measured. Label was incorporated into glutamic acid, aspartic acid, alanine, half-cystine, glycine, serine and proline. These amino acids are nonessential or dispensable. 4. 4. Threonine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan, lysine, histidine and arginine incorporated no label from glucose and are inferred to be essential. 5. 5. No conclusion was drawn concerning the essentiality of tyrosine.

Partial purification of a triacylglycerol lipase isolated from steelhead trout (Salmo gairdneri) adipose tissue

A triacylglycerol (TG) lipase (EC 3.1.1.2), assayed by monitoring [1-14C]-oleic acid release from [carboxyl-14C]-triolein after liquid-liquid partition of the fatty acid from the unhydrolyzed triacylglycerol substrate, was isolated and partially purified from steelhead trout adipose tissue. The TG lipase was resolved from contaminating lipoprotein lipase by heparin-sepharose affinity chromatography and purified ca. 71-fold over the original fraction. Optimal enzyme activity occurred at pH 7.5. The purified enzyme migrated on SDS-polyacrylamide gels with an apparent molecular weight of 48,000.

Chylomicra in the serum of postprandial steelhead trout (Salmo gairdnerii)

1. 1. Postprandial effects on serum lipoprotein distribution were determined in juvenile steelhead trout (Salmo gairdnerii). 2. 2. As many as eight lipoproteins were detected, including proteins of α, α2, and β mobility, as well as up to three discrete proteins with albumin-like mobility. 3. 3. Two and 4 hr after feeding, large electrophoretically-immobile lipoproteins, corresponding to chylomicra, were detected. 4. 4. Isolated d = 0.96 lipoproteins were 80% triacylglycerol; thus confirming the chylomicra-nature of these particles. 5. 5. The presence of triacylglycerol-rich chylomicra in the serum of trout suggests that exogenous lipid is, in part, transported to the body tissues of these animals in a manner similar to mammals.

Interorgan transport of lipids in the blood of the gumboot chiton Cryptochiton stelleri (Middendorff)

1. 1. Total blood lipid of C. stelleri approximates 7 mg/dl with 4 mg/dl in the plasma. The remaining 3 mg/dl is contained in the blood cells whose count averages ca. 3000/μ1. 2. 2. Plasma lipids contain appreciable amounts of alkyl-diacylglycerol (5%), triglyceride (15%) and free fatty acid (7%) which can be considered as potential transport forms of acyl lipid utilized by energy metabolism. Sterols and phospholipids constitute the remainder of the plasma lipids. 3. 3. Plasma contains 14 electrophoretically resolvable proteins including an apparent carotenoprotein and a high molecular weight lipoprotein. 4. 4. Ingested 1−14C-palmitate passes into the plasma lipid compartments and into tissues without direct contact with the gastro-intestinal tract (gonad, foot, mantle). The time course of labelling and the relative specific activities of plasma and tissue lipid classes suggest that plasma FFA are the principal transport form of acyl lipid. 5. 5. A preliminary effort to measure the rate of turnover of plasma FFA suggests that this process may support <10% of the energy metabolism of C. stellen.

Synthesis of essential amino acids by bacterial symbionts in the gills of the shipworm Bankia setacea (tryon)

Abstract o 1. The glands of Deshayes located in the gills of the shipworm Bankia setacea (Tryon), (Bivalvia, Teredinidae) contain cells similar to the mycetocytes of insects which harbor intracellular bacteria. 2. When isolated gills were incubated with [U- 14 C]glucose, essential amino acids (arginine, histidine, isoleucine, leucine, lysine, methionine, threonine, valine and phenylalanine) of the free and protein-bound pools became labeled. 3. This finding suggests the possibility that the prokaryotic symbionts of the mycetocytes may contribute to the nutrition of the shipworm by synthesizing essential nutrients which are in short supply in the natural diet (wood supplemented by plankton) of B. setacea . 4. Mantle tissue of B. setacea lacks mycetocytes. When isolated mantle was incubated with [U- 14 C]-glucose the only amino acids which became labeled were non-essential: alanine, aspartate, glutamate, glycine and serine. 5. Ultrastructural features of the mycetocytes are described. 6. Diaminopimelic acid, a component of bacterial cell walls, was detected after HCl hydrolysis of gill tissue. The bacteria of the mycetocytes have not, however, been characterized by standard culture methods.

The essential amino acid requirements of the Dungeness crab, Cancer magister

Abstract The essential amino acid requirements for juveniles of the Dungeness crab Cancer magister were determined by the radiometric method. Both the protein and free amino acids were quantified and their specific activities compared. Injection of five crabs with [U- 14 C] glucose resulted in the labelling of the amino acids cysteine, aspartate, serine, glutamate, proline, alanine, and glycine. One crab injected with [U- 14 C] glutamate showed results similar to the glucose-injected crabs, with the notable exception that proline did not become labelled. An animal injected with [U- 14 C] phenylalanine produced radioactive tyrosine, alanine, and glutamate. Since fumarate is one of the breakdown products of phenylalanine in those species that have been studied, the lack of labelled aspartate is of interest. These results suggest that cysteine, aspartate, serine, glutamate, alanine, proline, and glycine are dispensable and that tyrosine is dispensable if phenylalanine is supplied. The non-labelled amino acids threonine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan, lysine, histidine, and arginine are inferred to be essential.

Transport of lipids in the blood of the pacific oyster, Crassostrea gigas (Thunberg)

Abstract 1. 1. Total lipid concentrations of plasma of C. gigas vary from 4.2–12.5 mg/dl dependent upon nutritional and reproductive condition. Fasting and gonadal maturity both appear to increase plasma lipid. 2. 2. Hemocyte total lipid in fed, reproductively mature oysters in 6.7 mg/dl. 3. 3. Both plasma and hemocyte lipids consist mainly of phospholipid (70–80%), with lesser amounts of the neutral lipid classes: sterol (0.5–1.2%), free fatty acids (0.8–3.8%), triglycerides (2.6–5.5%) and sterol esters (0.2–2.1%). 4. 4. Oyster plasma contains 20 electrophoretically resolvable proteins, including 2 lipoproteins, which were present in very low concentration. 5. 5. When 1-14C-palmitate is fed to oysters, the specific activities of plasma and hemocyte lipids rise over a period of 10 hr and then maintain roughly steady levels. Specific activities of hemocyte and plasma lipids were approximately equal. Free fatty acids attained the highest specific activity of any blood lipid class. 6. 6. By 56 hr after ingestion of 1-14C-palmitate, radioactivity was found in the several lipid classes of tissues having only blood contact with the digestive tract, thus supporting the premise of transport of lipid through the hemolymph.

Interorgan transport of lipids in the purple sea urchin, Strongylocentrotus purpuratus

Abstract 1. 1. Total lipid expressed in mg/dl of whole coelomic fluid of sexually mature Strongylocentrotus purpuratus was divided between plasma, 1.05; red coelomocytes, 23.53; and white coelomocytes, 12.30. 2. 2. Sexually unripe animals had higher plasma lipid concentrations and lower coelomocyte packed cell volumes and total lipids. 3. 3. Triglycerides comprised from 25 to 50 per cent of the plasma lipids. Coelomocyte lipids consisted mainly of phospholipids and sterols. 4. 4. As many as twelve protein-staining bands could be resolved in serum samples by disc electrophoresis. One of the twelve bands stained with Sudan black B and may be a lipoprotein. 5. 5. When urchins were fed 1- 14 C-palmitate the labeling pattern of the acyl lipid classes of the several organs and the coelomic fluid suggested transport of lipid from the gut to other organs via the agency of the free fatty acid fraction of the coelomocyte lipids.

Wax esters in the liver and serum of steelhead trout Salmo gairdneri (Richardson)

1. Wax esters were identified in the serum and liver of steelhead trout. 2. Confirmation of the identity was made by thin-layer chromatography of the wax ester hydrolysis products: long chain alcohols and fatty acids. 3. Tissue concentrations of the wax are 0.34 mg/ml and 0.12 mg/g in the serum and liver respectively. 4. The presence of the wax esters in these two particular tissues suggests that the wax is synthesized in the liver, incorporated into lipoproteins, and functions as a lipid transport molecule.