Robert Scott Carr

Quantitative semi-automated enzymatic assay for tissue glycogen

A simple, rapid, specific and reproducible assay for tissue glycogen is described. The method involves the incubation of a denatured tissue homogenate with amyloglucosidase resulting in the complete hydrolysis of glycogen to glucose. The glucose content of the homogenate supernatant is then determined with the aid of a glucose analyzer. The method has been used to measure the glycogen content of a variety of discrete and complex animal tissues and is particularly convenient for microdeterminations.

A simple spectrophotometric technique for the determination of pentachlorophenol in water.

Pentacnlorophenol (PCP) and i t s sodium sa l t are the second most widely used biocides in the United States (CIRRELLI 1979) with the annual world production exceeding 20,000 tons (RAPPE & NILSSON 1972). The inevitable contamination of aquatic and marine environments resul t ing from agr icu l tura l and industr ia l usage of PCP has prompted a number of investigations concerning the fate and effects of th is chlorophenol in animals and the environment (RAO 1978).

Field assessment of biochemical stress indices for the sandworm Neanthes virens (Sars)

Abstract Certain biochemical stress responses have been observed in the laboratory for Neathhes virens subjected to various environmental and pollutant stressors. The purpose of the present study was to determine whether similar alterations in these biochemical parameters could be detected in a natural population of N. virens from a contaminated site as compared with animals from a nearby reference site. A site in Portland Harbor, Maine, adjacent to an oil storage facility with oil-contaminated sediments was selected as the experimental study area and the reference site was at Pine Point, approximately 15 miles south of Portland. Animals were collected from the two sites on consecutive days on a bimonthly basis at low tide within a day of the full moon from September 1981 through March 1982. Coelomic fluid samples were taken within 2 h after collection and the animals were then frozen in liquid nitrogen for transport back to the laboratory. Coelomic fluid samples were analyzed for glucose and the frozen tissues were analyzed for glycogen, lipid and free amino acid concentrations. Significant differences in these parameters were often observed between the two populations. The glycogen content of animals from the contaminated site was always less than that of animals from the reference site, whereas the lipid levels were always higher. Significant differences between the free amino acid composition of the animals from the two sites were also observed. Although distinct biochemical differences can be detected between these two populations, the considerable biological variation in these parameters may limit their usefulness for field monitoring investigations for this species.

Biochemical indices of stress in the sandworm neanthes virens (Sars). I. responses to pentachlorophenol

Abstract Neanthes virens (Sars) were exposed to acute lethal and chronic sublethal concentrations of pentachlorophenol (PCP) in the laboratory. Coelomic fluid glucose and osmolality and tissue ascorbic acid and glycogen were monitored in order to assess the time-course response of this polychaete to pollutant stress. Glycemic responses and alterations in tissue ascorbic acid and glycogen levels were observed to be dose and time-dependent. During the acute lethal exposure (720 μg/I initially), a hypoglycemic response was evident during the first 8 h of exposure. At a less severe but still lethal exposure concentration (365 μg/I initially), a significant hyperglycemic response was observed after 21 h. The coelomic fluid glucose levels decreased gradually during the 4-day exposure as glycogen reserves were depleted. During the chronic (ca. 2-mth) exposure to 100 μg PCP/1. no unusual glycemic responses were observed. Glycogen reserves remained constant during the first month of exposure but were significantly depleted after 2 mth. Ascorbic acid levels became elevated in PCP-exposed worms after I wk in both parapodial tissue and posterior segments. This tendency continued throughout the exposure period and the difference between the exposed and control values was statistically significant at the termination of the experiment. An uptake and depuration experiment with14C-PCP was also conducted. Polychaetes exposed to 100 μg/l14C-PCP for 2 wk accumulated ca. 280 times the ambient exposure concentration on a wet weight basis. After 2 wk of depuration the mean PCP body burden of depurated animals had decreased by 29%.

Field assessment of biomarkers for winter flounder

Abstract Winter flounder, Pseudopleuronectes americanus, from Boston Harbor near the Deer Island sewage outfall and from a nearby reference population near Plymouth Beach, Massachusetts, USA, were collected on several occasions and analysed for a variety of biochemical variables and histopathological conditions. A number of biochemical variables including hepatic and pectoral fin ascorbic acid concentrations, hepatic glycogen and lipid levels, plasma glucose concentrations, brain serotonin and norepinephrine concentrations, and the concentration and ratio of various free amino acids in muscle tissue were significantly different between the two populations. The apparent apoptotic hepatic lesions were found in the majority of the winter flounder collected from Boston Harbor and were rarely observed in animals from the reference site. Low tissue concentrations of ascorbic acid and hepatic glycogen were found to have significant statistical associations with the presence and degree of severity of these hepatic lesions.

Biochemical indices of stress in the sandworm Neanthes virens (SARS). II. Sublethal responses to cadmium

Abstract The concentration of coelomic fluid glucose and tissue ascorbic acid and glycogen were monitored in Neanthes virens during exposure to sublethal concentrations of cadmium. The responses of N. virens to cadmium were both time and dose-dependent and followed a pattern which is consistent with the general adaptation syndrome. After 3 days of exposure to 10 mg/l Cd, a significant hyperglycemic response was observed which persisted for over a month until the glycogen reserves were depleted. At the termination of the chronic (2-mth) exposure, the tissue ascorbic acid concentration of the Cd-exposed animals was significantly higher than the controls. Glycogen appears to be a limiting constituent during chronic pollutant stress for this polychaete whereas ascorbic acid is not.

Influence of prior exposure to xenobiotics on the metabolism and distribution of polychlorinated biphenyls and phenanthrene in winter flounder, Pseudopleuronectes americanus

Abstract The purpose of this study was to determine the effect of prior exposure and multiple-contaminant exposure on the ability of winter flounder to metabolize specific organic compounds. In addition to these pharmacokinetic studies, the intracellular binding patterns of phenanthrene metabolites to liver cytosolic constituents of winter flounder from the different treatments were investigated. In the first experiment, one group of winter flounder was fed by gavage a dose of 14C-labeled polychlorinated biphenyls (PCBs); a second group of fish received a dose of both PCB and cadmium. In a second experiment, winter flounder were exposed for four weeks in a flow-through system to a mixture of copper, cadmium, lead, and PCBs before they received either a dose of 14C-PCB or a dose of 14C-phenanthrene. Liver cytosols from the second experiment were chromatographed by aqueous gel permeation chromatography (AGPC) and the radioactivity associated with 1 ml fractions of the eluate determined by liquid scintillation counting. The results of these experiments suggest that both pre-exposure and/or multiple-contaminant exposures increase the rate at which winter flounder can metabolize both PCBs and phenanthrene. The results also suggest that phenanthrene metabolites were bound to enzymes. There were no apparent differences in the intracellular distribution of radioactivity or the UV and fluorescence chromatograms between liver cytosols from animals from the different treatments.