Biggers William J.

No Thumbnail Available
Last Name
Biggers
First Name
William J.
ORCID

Filters

2004 - 2005 2
2
2
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Article
    Response of the American lobster to the stress of shell disease
    (National Shellfisheries Association, 2005-10) Laufer, Hans ; Demir, Neslihan ; Biggers, William J.
    Shell disease is a problem affecting lobsters in eastern Long Island Sound causing disfiguration of the shell, decreasing the lobsters' value, and whereas mild and medium levels of the disease are not lethal, ultimately, severe cases result in mortality. Levels of the molting hormone, ecdysone, were quantitated, using a radioimmunoassay (RIA), in hemolymph of animals exhibiting shell disease. Our results indicate that levels of ecdysone were increased in the hemolymph of shell-diseased lobsters, with a medium level of expression of the disease to 89 ± 32 ng/mL (n = 76), whereas unaffected, presumably healthy ones had 57 ± 16 ng/mL (n = 210). In 7 of 10 months of the year shell-diseased animals had higher ecdysone levels in their hemolymph than unaffected animals. In addition, ecdysone levels were abnormally high, 165 ± 53 ng/mL (n = 5), in shell-diseased ovigerous lobsters, whereas normal unaffected ovigerous ones had low levels of this hormone, 13 ± 4 ng/mL (n = 7). These results indicate that shell disease may induce lobsters to alter the systemic levels of ecdysone, possibly serving as a defensive measure, allowing the animals to ward off the effects of shell disease through induced molting.
  • Article
    Identification of juvenile hormone-active alkylphenols in the lobster Homarus americanus and in marine sediments
    (Marine Biological Laboratory, 2004-02) Biggers, William J. ; Laufer, Hans
    We have identified, by gas chromatography/mass spectrometry, four alkylphenols that are present in the hemolymph and tissues of the American lobster Homarus americanus and in marine sediments. These alkylphenols are used industrially in antioxidant formulations for plastic and rubber polymer manufacturing, and are similar in structure to a known endocrine disruptor, bisphenol A. The compound 2-t-butyl-4-(dimethylbenzyl)phenol was present at concentrations of 0.02 to 1.15 µg/ml in hemolymph and 8.95 to 21.58 µg/g in sediments. A second compound, 2,4-bis-(dimethylbenzyl)phenol, was present at concentrations between 0.07 and 19.78 µg/ml in hemolymph and 138.94 to 224.89 µg/g in sediment, while a third compound, 2,6-bis-(t-butyl)-4-(dimethylbenzyl)phenol, was found at concentrations between 0.01 and 13.00 µg/ml in hemolymph, 2.55 and 6.11 µg/g in hepatopancreas, and 47.85 and 74.66 µg/g in sediment. A fourth compound, 2,4-bis-(dimethylbenzyl)-6-t-butylphenol, was found at concentrations of 0.20 to 70.71 µg/ml in hemolymph, 23.56 to 26.89 µg/g in hepatopancreas, and 90.68 to 125.58 µg/g in sediment. These compounds, along with bisphenol A, 4-dimethylbenzylphenol, and nonylphenol, display high juvenile hormone activity in bioassays. Alkylphenols at high concentrations are toxic to crustaceans and may contribute significantly to lobster mortality; at lower concentrations, they are likely to have endocrine-disrupting effects.