Immunoassays based on monoclonal antibodies (mAbs) are highly sensitive for the detection of polycyclic aromatic hydrocarbons (PAHs) and can be employed to determine concentrations in near real-time. A sensitive generic mAb against PAHs, named as 2G8, was developed by a three-step screening procedure. It exhibited nearly uniformly high sensitivity against 3-ring to 5-ring unsubstituted PAHs and their common environmental methylated PAHs, with IC50 values between 1.68–31 μg/L (ppb). 2G8 has been successfully applied on the KinExA Inline Biosensor system for quantifying 3-5 ring PAHs in aqueous environmental samples. PAHs were detected at a concentration as low as 0.2 μg/L. Furthermore, the analyses only required 10 min for each sample. To evaluate the accuracy of the 2G8-based biosensor, the total PAH concentrations in a series of environmental samples analyzed by biosensor and GC-MS were compared. In most cases, the results yielded a good correlation between methods. This indicates that generic antibody 2G8 based biosensor possesses significant promise for a low cost, rapid method for PAH determination in aqueous samples.

The protozoan oyster parasite Perkinsus marinus can be cultured in vitro in a variety of media; however, this has been associated with a rapid attenuation of infectivity. Supplementation of defined media with products of P. marinus-susceptible (Crassostrea virginica) and -tolerant (Crassostrea gigas, Crassostrea ariakensis) oysters alters proliferation and protease expression profiles and induces differentiation into morphological forms typically seen in vivo. It was not known if attenuation could be reversed by host extract supplementation. To investigate correlations among these changes as well as their association with infectivity, the effects of medium supplementation with tissue homogenates from both susceptible and tolerant oyster species were examined. The supplements markedly altered both cell size and proliferation, regardless of species; however, upregulation of low-molecular-weight protease expression was most prominent with susceptible oysters extracts. Increased infectivity occurred with the use of oyster product-supplemented media, but it was not consistently associated with changes in cell size, cell morphology, or protease secretion and was not related to the susceptibility of the oyster species used as the supplement source.Perkinsus marinus is a protozoan parasite of the eastern oyster Crassostrea virginica. Mortalities caused by this parasite typically occur in the second summer of infection and have been responsible for much of the recent decline in the oyster fishery along the eastern seaboard of the United States (3, 15). The molecular mechanisms of parasite infectivity, virulence, and interaction with the host defense system are largely unknown. The development of media formulations allowing axenic culture of P. marinus has provided new opportunities to assess the effects of host components on parasite growth, physiology, and infectivity. There are several media formulations for in vitro P. marinus culture that employ commercial base formulations (e.g., Dulbecco modified Eagle's medium with Ham's F-12 nutrient mixture) supplemented with such constituents as cod liver oil, bovine serum albumin, yeastolate, or fetal bovine serum (FBS) or its ␣-fetoprotein constituent, fetuin (11,18,19,21,23,26). There is also a chemically defined, protein-free medium ) which has proven to be of particular value for the production of antibodies against P. marinus extracellular products (12).The in vivo P. marinus life cycle begins with a small, immature trophozoite that enlarges over time into a "signet ring" form, so named for its large vacuole and offset nucleus. This mature trophozoite may then undergo palintomic fission, in which 4 to 64 or more immature trophozoites are formed within, then exit from, the parental cell, or tomont, wall (35). P. marinus can also form motile zoospores, again by palintomic fission, with exit of the zoospores through a discharge tube and pore structure formed on the wall of the enlarged parental trophozoite, the zoosporangium (35). During in vitro culture in ODRP-3 medium, ce...

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