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Acute toxicity tests were performed on field-collected copepods (Microarthridion littorale) using the sediment-associated polychlorinated biphenyl (PCB) Aroclor 1254 (i.e., PCB concentrations in bulk sediments in the bound and/or unbound states). Three replicates of 50 adult copepods were exposed to five levels of PCB-contaminated sediments for 96 h and compared to untreated controls and solvent controls. LC50 concentrations were nearly twice as high for females as for males. To determine the effects of the PCB on reproductive output of the copepods, copulating pairs of Microarthridion littorale were allowed to reproduce in concentrations of Aroclor 1254-contaminated sediments below LC50 values. Two experimental trials with 10 and 15 replicates, each with one pair of Microarthridion littorale in copulus, were conducted for 12 d, the normal time needed for females to produce one set of nauplii and carry a second clutch of eggs. In both experiments, a significant decrease in number of nauplii was found with Aroclor contamination. Although NOECs were not determined, high concentrations of the sediment-associated Aroclor NOECs were required to affect mortality significantly, whereas lower levels impaired reproduction.

Comparative effects of aqueous-, pore-water-, and sediment-phase cadmium on mortality of an infaunal laboratory-cultured copepod, Amphiascus tenuiremis, were determined using acute 96-h bioassays. Experimental design included five cadmium concentrations, three replicates per concentration, and 50 adult copepods per replicate for each of the exposures. Exposures included cadmium solubilized in seawater only (aqueous), whole sediment (i.e., pore water and sediment), and pore water only. In addition, two whole-sediment bioassays were compared in which pore-water cadmium concentrations were altered experimentally but sediment concentrations remained the same. Results of these experiments showed that for Amphiascus tenuiremis, cadmium is most toxic in the aqueous phase, less toxic in the pore-water phase, and least toxic in the sediment-bound phase. The lowered toxicity of cadmium in the pore water was most likely due to complexation of cadmium with DOC, because concentrations of DOC were six times higher in the pore-water phase than in the aqueous phase. In whole sediments, pore-water-phase cadmium was the primary source of acute toxicity, as sediment-associated cadmium contributed negligible effects.

The benthic harpacticoid copepod, Amphiascus tenuiremis, was cultured through one generation at four concentrations (600, 300, 150, and 0 micrograms/kg) of sediment-associated fenvalerate, a synthetic pyrethroid insecticide, to assess effects on reproductive output and age structure. Two static renewal experiments with four replicates of each treatment were conducted. At the end of 21 days, surviving copepods were sorted and counted into adult males, adult females, copepodites, and nauplii. Fenvalerate was extracted from the sediment and measured by GC-MS. The number of individuals in each life-history stage in fenvalerate treatments was not significantly different from controls, except for increased adult females in fenvalerate in the second experiment. The overall lack of a fenvalerate toxic effect on A. tenuiremis was most likely because fenvalerate tightly binds to sediments and was probably not bioavailable to the copepods. Sediment-associated pesticides with large octanol:water partitioning coefficients (K(ow)'s) such as fenvalerate appear to be less toxic to infaunal copepods than those exhibiting smaller K(ow)'s.

Endosulfan-contaminated muddy sediments were collected from a tidal creek bottom after rain runoff from an agricultural watershed and tested for their effects on larval settlement/growth, survival and reproduction of cultured meiobenthic polychaetes and copepods. Endosulfan (ES) strongly inhibited larval colonization and early juvenile growth of the cosmopolitan, euryhaline polychaete Streblospio benedicti. In laboratory microcosms, ES concentrations as low as 50 μg·kg−1 sediment significantly reduced the number of larval colonists by >50% relative to ES-free control sediments. Higher concentrations closer to actual field levels suppressed Streblospio benedicti colonization completely. Early growth of newly metamorphosed juveniles was depressed 36 and 40% relative to controls at ES concentrations of 50 and 100 μg·kg−1, respectively. In contrast, when the common benthic harpacticoid copepod Pseudobradya pulchella was chronically exposed to sediment ES as high as 200 μg·kg−1, survival and egg production were unaffected despite many examples of high ES toxicity to other crustaceans. Of more than 1,600 Pseudobradya pulchella tested, more than 95% survived ES concentrations of at least 200 μg·kg−1, and over 98% of 1,200 females produced normal clutches of eggs. Similarly, survival of another common benthic copepod, Nannopus palustris, was not significantly affected below a threshold concentration of 200 μg·kg−1 ES. At 200 μg·kg−1, however, Nannopus palustris' survival was significantly reduced relative to control and 50-μg·kg−1 ES treatments.

Single-walled carbon nanotubes (SWNT) have extremely high affinity for hydrophobic organic contaminants, considerably higher than natural or refractory (e.g., soot and detrital) carbon found in sediments. To evaluate the effect of sediment-associated SWNT on contaminant uptake from sediments by infaunal deposit feeders, we have conducted a comparative bioaccumulation study using two infaunal estuarine invertebrates. The deposit-feeding meiobenthic copepod Amphiascus tenuiremis and the deposit/suspension-feeding polychaete Streblospio benedicti were exposed to hydrophobic organic contaminants (HOCs) including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and polybrominated diphenyl ethers for 14 days in the presence of sediment amended with (1) SWNTs, (2) NIST diesel soot, or (3) no carbon amendment. Coaddition of SWNT to sediments significantly reduced bioaccumulation of HOCs in S. benedicti; however, soot addition tended to increase the bioaccumulation of these same compounds in the polychaete worm. Bioaccumulation of HOCs from sediments by copepods (A. tenuiremis) was less dependent on black carbon addition to sediment; neither SWNT nor soot significantly impacted bioaccumulation of PAHs from sediment by this organism. Exposure of both copepods and polychaetes to radiolabeled (14C) SWNT in estuarine sediments revealed that these organisms did not assimilate these materials into their tissues, although S. benedicti did ingest 14C-SWNT, as fecal rods from this organism contained identical 14C activity as that of the sediment to which the worms were exposed.

Attached bacteria inhabit the surfaces of many marine animals--a process that may play important roles in the survival and transport through aquatic systems. However, efficient detection of these bacteria has been problematic, especially small aquatic animals such as benthic harpacticoid copepod. Quantum dots (QD) have recently emerged as a significant tool in immunofluorescence detection because of their unique properties compared to other fluorescent probes. In the present study, a polyclonal antibody was raised against the Gram-negative marine bacterium, Alteromonas sp. A microplate-based immunofluorescence bioassay using QD strepavidin conjugates was developed for quantifying putative Alteromonas sp. cells located on the surfaces of a marine harpacticoid copepod, Microarthridion littorale. The number of attached Alteromonas sp. was estimated to be 10(2)+/-8 CFU using this method. The QD approach, coupled to a microplate assay can potentially provide an efficient and accurate method for rapidly detecting multiple bacteria species attached to small invertebrate animals because of their unique excitation and emission characteristics.

Fish embryo toxicology is important because embryos are considered more susceptible than adult fish to the effects of toxic chemicals. Recently, fish embryo bioassay was proposed to replace the conventional fish acute toxicity chemical test of the Organization for Economic Cooperation and Development guidelines because it offers the advantages of fewer reagents, easy handling, and efficient data production. To accelerate the establishment of a chemical toxicity database for the protection of environmental and human health, we need to determine whether the conventional toxicity test can safely be replaced by such fish embryo toxicity tests. For instance, it is unclear how the presence of the chorion moderates the toxic effects of some chemicals. If such chemical toxicities do differ between embryos and, for example, the larval stage, then different toxic effects should appear in later life. We tested the later-life effects of the neurotoxic insecticide carbaryl at sublethal concentrations (0 [control] and 5 and 10 mg/L) in embryos and posthatch larvae of the freshwater fish medaka, Oryzias latipes. Although embryos exposed until hatching showed multiple developmental malformations and reductions in subsequent survival rates over three months, no significant reduction was observed in tolerance to starvation for 7 d and in intrinsic population growth rate (r). Exposure of larvae for 96 h resulted in dose-responsive vertebral fracture, significant reduction in tolerance to starvation for 7 d, and reduced three-month survival rate; r was reduced significantly and consistently. These results suggested that posthatch larvae were more susceptible than embryos to carbaryl exposure and that the toxic cascades may differ between larvae and embryos. The influences of carbaryl exposure on population growth rate differed significantly with developmental stage.

Pure, microcosm-cultured populations of benthic copepods were established from pristine or pesticide-impacted Spartina marsh creeks and used as efficient bioassay groups to assess lethal and sublethal effects of sediment-bound pesticide residues. Naturally-weathered sediments contaminated with the synthetic pyrethroid insecticide fenvalerate were collected by traps moored in a tidal creek receiving major pesticide-laced runoff from an agricultural watershed, and used as dosing material. Silty sediments with fenvalerate residues reaching 100 ppb were trapped and then diluted with uncontaminated sediments to achieve an exposure range of 0, 25, 50 and 100 ppb (i.e. no dilution). Despite a broad database showing extreme sensitivity to water-solubilized fenvalerate by many marine invertebrates and fishes, a 7-day exposure to sediment-bound residues as high as 100 ppb caused no significant mortality for any life stages (i.e. nauplii, copepodites or adults) of the benthic harpacticoid copepods Microarthridion littorale or Paronychocamptus wilsoni, and no mortality for adults of Enhydrosoma propinquum. However, sediment-bound residues as low as 25 ppb significantly depressed egg production (50–100% reduction) and mean clutch sizes (40–100% reduction) of fertile M. littorale and P. wilsoni. If sedimenting fenvalerate depresses copepod reproduction in the field, then lowered recruitment of new individuals will lead inevitably to a decline in population growth.

Objective: To evaluate the safety and efficacy of orally administered ruboxistaurin (RBX) as a mesylate salt in patients with diabetic macular edema (DME). 1Design: Multicenter, double-masked, randomized, placebo-controlled study of 686 patients receiving placebo or RBX orally ( 4, 16, or 32 mg/d) for 30 months. At baseline, patients had DME farther than 300 mu m from the center of the macula, an Early Treatment Diabetic Retinopathy Study retinopathy severity level from 20 to 47A without prior photocoagulation, and an Early Treatment Diabetic Retinopathy Study visual acuity of 75 or more letters in the study eye. The primary study outcome was progression to sight-threatening DME or application of focal/grid photocoagulation for DME.Main Outcome Measure: Masked grading of stereoscopic fundus photographs.Results: The delay in progression to the primary outcome was not statistically significant ( 32 mg of RBX vs placebo, P=.14 [unadjusted]; Cox proportional hazards model adjusted for covariates, hazards ratio=0.73; 95% confidence interval, 0.53-1.0; P=.06). However, application of focal/ grid photocoagulation prior to progression to sight-threatening DME varied by site, and a secondary analysis of progression to sight-threatening DME alone showed that 32 mg of RBX per day reduced progression, compared with placebo (P=.054 [ unadjusted]; Cox proportional hazards model, hazards ratio= 0.66; 95% confidence interval, 0.47-0.93; P=.02).Conclusions: Although progression to the primary outcome was not delayed, daily oral administration of RBX may delay progression of DME to a sight-threatening stage. Ruboxistaurin was well tolerated in this study.

Serial analysis of gene expression (SAGE) is a transcriptome-profiling technique that allows accurate gene expression profiles to be generated without any need for prior sequence knowledge, making it ideal for assaying toxicant-specific genetic responses in nonmodel species. We used SAGE to perform a large-scale survey of the Palaemonetes pugio transcriptome under different chemical xenobiotic stresses. Four libraries were constructed from fipronil-exposed, endosulfan-exposed, and cadmium-exposed shrimp, as well as from carrier-control-exposed shrimp. A total of 37,152 tags were sequenced from the four libraries, including 13,754 unique tags. Statistical analysis revealed that 117 tags were differentially expressed significantly in at least one of the three exposures. Cluster analyses of the altered tags showed that fipronil and endosulfan elicit transcriptome profiles that are more similar to each other than either one was to cadmium. Quantitative polymerase chain reaction (QPCR) was performed on a subset of 46 differentially expressed tags, and largely confirmed the SAGE results. The tags were filtered to identify tags for which both SAGE and QPCR agreed in regard to the direction and magnitude of affect, and which were informative about the exposure experienced. A subset of 16 tags was identified that represents a putative biomarker suite that is indicative of exposures to the three toxicants.

Single-walled carbon nanotubes (SWNT) are finding increasing use in consumer electronics and structural composites. These nanomaterials and their manufacturing byproducts may eventually reach estuarine systems through wastewater discharge. The acute and chronic toxicity of SWNTs were evaluated using full life-cycle bioassays with the estuarine copepod Amphiascus tenuiremis (ASTM method E-2317-04). A synchronous cohort of naupliar larvae was assayed by culturing individual larvae to adulthood in individual 96-well microplate wells amended with SWNTs in seawater. Copepods were exposed to "as prepared" (AP) SWNTs, electrophoretically purified SWNTs, or a fluorescent fraction of nanocarbon synthetic byproducts. Copepods ingesting purified SWNTs showed no significant effects on mortality, development, and reproduction across exposures (p0.05). In contrast, exposure to the more complex AP-SWNT mixture significantly increased life-cycle mortality, reduced fertilization rates, and reduced molting success in the highest exposure (10 mg x L(-1)) (p0.05). Exposure to small fluorescent nanocarbon byproducts caused significantly increased life-cycle mortality at 10 mg x L(-1) (p0.05). The fluorescent nanocarbon fraction also caused significant reduction in life-cycle molting success for all exposures (p0.05). These results suggest size-dependent toxicity of SWNT-based nanomaterials, with the smallest synthetic byproduct fractions causing increased mortality and delayed copepod development over the concentration ranges tested.

The U.S. National Institute of Standards and Technology (NIST) petroleum crude oil was used to generate NIST water-accommodated hydrocarbon fractions (WAFs) for standardized assessment of crude oil effects on the copepod Amphiascus tenuiremis. Effects were assessed using a 96-well microplate, full life-cycle test. Briefly, nauplii (age, 24 h) were reared individually to adults (nor =120 nauplii/treatment) in microplate wells containing 200 microl of treatment solution (seawater control [0%] or 10, 30, 50, or 100% NIST-WAF). Nauplii were monitored through development to adulthood, and mature virgin male:female pairs mated in wells containing original treatments (30 d). A second bioassay using 0, 10, 30, and 50% WAFs (nor =60 nauplii/treatment) was conducted to assess the effects of ultraviolet (UV) light on naupliar endpoints (16 d). In the first experiment, nauplius-to-copepodite survival in exposures to 100% WAF was 27% +/- 6% lower than in controls (92% +/- 1%), but copepodite-to-adult survival was greater than 90% across all treatments. Analysis of development curves showed that nauplii in the 10% WAF developed into copepodites 25% faster, whereas nauplii in the 50 and 100% WAFs developed 17% slower, than controls. Copepodite development into male and female copepods was significantly delayed (2 and 4 d, respectively) in the 100% WAF compared to controls. Although none of the WAF exposures had significant effects on fertilization success or total viable production (p0.05), embryo hatching in the 100% WAF was significantly less (70.0% +/- 21.2%) than that in controls (87.0% +/- 19.4%). Results from the UV bioassay showed that relatively short exposures (14 d) to 30 and 50% WAFs in the presence of UV light caused negative effects on copepod survival and development. Naupliar-stage survival and developmental endpoints were the most sensitive indicators of exposure to the NIST crude oil WAF

Confocal laser scanning microscopy (CLSM) represents a powerful, but largely unexplored ecotoxicologic tool for rapidly assessing in vivo effects of toxicants on marine invertebrate embryo quality and development. We describe here a new semiquantitative CLSM approach for assessing relative yolk quantity in marine invertebrate embryos (harpacticoid copepods) produced by parents reared from hatching to adult in the polycylic aromatic hydrocarbon chrysene. This method is based on fluorogenic labeling of embryo yolk and subsequent statistical analysis of areal pixel intensities over multiple Z-series using a general linear model (GLM)-nested analysis of variance. The fluorescent yolk-labeling method described here was able to detect statistically significant differences in yolk concentrations in marine copepod (Amphiascus tenuiremis) eggs or embryos from females exposed to ultraviolet light and chrysene-contaminated sediments. Yolk intensities in embryos from females cultured throughout their life cycles in clean sediments were statistically identical with or without UV exposure. In contrast, yolk intensities in embryos of females cultured throughout their life cycle in chrysene-contaminated sediments were significantly higher in the non-UV-exposed treatment with chrysene at 2500 ng/g sediment (65.7% higher) and the UV-exposed treatment with chrysene at 500 ng/g sediment (76.6% higher).

Vitellogenin (VTG) has been widely used as a biomarker of estrogenic exposure in fish, leading to the development of standardized assays for VTG quantification. However, standardized quantitative assays for invertebrate, particularly crustacean, lipovitellin (also known as vitellin [VTN]) are lacking. In this study, a fluorescence-based VTN enzyme-linked immunosorbent assay (ELISA) was developed to quantify microquantities of VTN in the estuarine, sediment-dwelling copepod Amphiascus tenuiremis. This ELISA utilizes a VTN-specific polyclonal antibody developed against amphipod (Leptocheirus plumulosus) embryo VTN and exhibits specificity toward female copepod proteins. In routine assays, the working range of the ELISA was 31.25 to 1,000 ng/ml (75-25% specific binding/maximum antibody binding [B/B0]) with a 50% B/B0 intra- and interassay variation of 3.9% (n = 9) and 12.5% (n = 26), respectively. This ELISA is capable of detecting VTN as low as 2 ng/ml, and can accurately detect VTN in as few as four copepods. The ELISA significantly discriminated positive (gravid female) and negative (male) samples, and was suitable for screening endocrine toxicity in copepods. Stage-I juvenile copepods were individually reared to adults in aqueous microvolumes of the phenylpyrazole insecticide, fipronil, and whole-body homogenate extracts were assayed for VTN levels. Fipronil-exposed virgin adult females, but not males, exhibited significantly higher levels of VTN relative to control males and females. This crustacean VTN ELISA is likely useful for evaluating endocrine activity of environmental toxicants in copepods and other crustacean species.

Fipronil is a novel gamma-aminobutyric acid receptor-specific phenylpyrazole insecticide commonly used near estuarine environments for rice production, turf-grass management, and residential insect control. In this study, we evaluated the acute, developmental, and reproductive toxicity of fipronil to the estuarine harpacticoid copepod Amphiascus tenuiremis. Fipronil was highly toxic to A. tenuiremis (adult 96-h median lethal concentration [LC50] = 6.8 microg/L) and was more toxic to male copepods (96-h LC50 = 3.5 microg/L) than to nongravid female copepods (96-h LC50 = 13.0 microg/L). By using a newly developed 96-well microplate-based life-cycle toxicity test, we successfully reared single individuals of A. tenuiremis to adulthood in 200-microl microwells and concurrently assessed developmental and reproductive effects (after paired virginal matings) of environmentally relevant aqueous fipronil concentrations (0.16, 0.22, and 0.42 microg/L measured). Throughout the entire life cycle, copepod survival in all treatments was90%. However, fipronil at 0.22 microg/L and higher significantly delayed male and female development from stage 1 copepodite to adult by approximately 2 d. More importantly, fipronil significantly halted female egg extrusion by 71% in the 0.22-microg/L fipronil treatment, and nearly eliminated reproduction (94% failure) in the 0.42-microg/L fipronil treatment. A three-generation Leslie matrix-based population growth model of fipronil reproductive and life-cycle impacts predicted a 62% decline in population size of A. tenuiremis relative to controls at only 0.16 microg/L.

Copepods are the most abundant arthropods on earth and are often the most important secondary producers in estuarine/marine food webs. The new GABA (gamma-aminobutyric acid)-disrupting insecticide fipronil (FP) induces unique sex-specific reproductive dysfunction in male meiobenthic copepods, leading to trans-generational population depression at environmentally realistic concentrations (0.63 microg/L). Using a newly developed 96-well microplate lifecycle bioassay, more than 700 individual Stage-I juveniles were reared to adulthood in as short as 12 days in only 200 microL of control (CTL) or 0.63 microg-FP/L seawater solution. Individual virgin male: female pairs were then cross-mated for all possible combinations within and across rearing treatments and allowed to mate for an additional 12 days in CTL or 0.63 microg-FP/L solution. FP at 0.63 microg/L caused no significant lethality to any mating combinations but evoked 73% or 89% inhibition of reproduction when FP-reared males were mated with either a control- or FP-reared female in FP solution, respectively. In contrast, when CTL-reared males were mated with FP-reared females in FP solution, there was no difference in reproductive success compared to FP-free controls. When FP-reared males were mated with either female group in FP-free solution, these mating pairs displayed a 3-day delay in time to brood sac extrusion but ultimately did reproduce. As fipronil (1) has a high K(ow), (2) is persistent in sediments where meiobenthic copepods live, and (3) has been detected in estuarine waters >0.7 microg/L, it may pose high risk to copepod production in estuarine systems.

Atrazine is one of the most widely used herbicides in the United States. Atrazine concentrations in coastal environments chronically range from 90 ng/L to 46 microg/L, with rare but measured concentrations near 60 microg/L at edge-of-field conditions. Chronic atrazine effects on estuarine benthos exposed to environmentally relevant concentrations are unknown. The purpose of this research was to assess atrazine reproductive and developmental effects over multiple-generation exposures of the copepod Amphiascus tenuiremis. Copepods were chronically exposed to two environmentally relevant nominal atrazine concentrations (2.5 and 25 microg/L, and to an environmentally unrealistic concentration (250 microg/L). Chronic exposures were performed using a 96-well microplate life cycle bioassay. Individual stage I copepodites (C1, n = 60/treatment) were reared through two generations (F0 and F1) to sexual maturity and individually mated in microwells containing 200 microl of atrazine solution. Copepod survival across all treatments and generations was >95%. Atrazine did not affect development to reproductive maturity, time to egg extrusion, or time to egg hatch (p > 0.05). However, reproductive failures increased across generations with increasing atrazine concentrations. Reproductive failures in the 0-, 2.5-, 25-, and 250-microg/L atrazine treatments were 11, 11, 20, and 24% for the F0 and 4, 9, 26, and 38% for the F1, respectively. Compared to controls, total nauplii production per female was reduced by approximately 22% in F0 females exposed to 250 microg/L atrazine (p < 0.05), and by approximately 23%, approximately 27%, and approximately 32% in F1 females exposed to 2.5-, 25-, and 250-microg/L atrazine treatments, respectively (p < 0.05). The combined effect of reproductive failure and reduced offspring production significantly reduced total population growth in the F1 generation (p < 0.05) even at atrazine concentrations lower than that considered safe for seawater chronic exposure (26 microg/L).

Under estuarine conditions, hydrophobic pesticides undergo physical/chemical partitioning into dissolved and particulate fractions of sediments. Our experimental study using 14C-chlorpyrifos (14C-CHPY) showed that sorptive associations of this common insecticide with particulate (>0.2 microm) and dissolved fractions (

Endocrine function in arthropods has principally been characterized in insects and malacostracan crustaceans. However, meiofauna represent the most abundant metazoan marine taxa, with harpacticoid copepods comprising the second most abundant taxon. In addition, their diminutive biomass has made characterization of endocrine components difficult, so little is known about endocrine control of reproduction, molting, and growth in meiofauna. In this study, a sensitive fluorometric enzyme immunoassay (EIA) was utilized to quantify and compare the arthropod molting hormone, 20-hydroxyecdysone (20E), in various life-cycle and developmental stages of a laboratory reared meiobenthic copepod, Amphiascus tenuiremis, and in an amphipod, Leptocheirus plumulosus. In copepods, gravid females carrying late stage pre-hatch embryos contained significantly more 20E (390+/-252 fmol/female) than gravids carrying early (Stage-I) embryos (172+/-83 fmol/female). In contrast, ecdysteroid levels in Stage-I L. plumulosus gravid females (277+/-83 fmol/female) was greater than pre-hatch gravid females (146+/-42). Stage-I embryos of both copepods (19+/-10) and amphipods (11+/-5 fmol/embryo) possessed lower ecdysteroid content than copepod (35+/-15) and amphipod (43+/-33 fmol/embryo) pre-hatch embryos. Ecdysteroid levels were also assessed in naupliar, juvenile, adult male and non-gravid female copepod life-stages. In addition, ecdysteroids measured in field collected copepod species indicated gravid females possessed ecdysteroid levels similar to gravid A. tenuiremis. However, upon normalization of egg sac 20E content by brood size, embryos from larger broods contained lower levels of ecdysteroids when compared to embryos from smaller clutch sizes-indicating an inverse embryo/ecdysteroid relationship may exist across species.

Vitellin is a major yolk protein that plays a significant role in the embryonic development of crustacean embryos. This protein was rapidly purified from embryos of the estuarine amphipod, Leptocheirus plumulosus, by subjecting the crude protein homogenate to high affinity column chromatography. SDS-PAGE revealed a single band with an approximate molecular weight of 200,000 daltons. Vitellin was characterized by SDS-PAGE techniques and amino acid composition analysis. L. plumulosus vitellin is a lipoglycophosphoprotein with serine, glutamic acid/glutamine, alanine, and aspartic acid/asparagine accounting for almost 66% of all amino acid residues. Polyclonal antibodies were raised against L. plumulosus vitellin and antibody reactivity was verified by dot-blotting and immuno-fluorescence confocal microscopy. These antibodies are specific for purified vitellin and show little cross-reactivity with other embryonic proteins.

An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae.

Sublethal test methods are being used with increasing frequency to measure sediment toxicity, but little is known about the relative sensitivity of these tests compared to the more commonly used acute tests. The present study was conducted to compare the sensitivity of several acute and sublethal methods and to investigate their correlations with sediment chemistry and benthic community condition. Six sublethal methods (amphipod: Leptocheirus plumulosus survival, growth, and reproduction; polychaete: Neanthes arenaceodentata survival and growth; benthic copepod: Amphiascus tenuiremis life cycle; seed clam: Mercenaria mercenaria growth; oyster: Crassostrea virginica lysosome destabilization; and sediment-water interface testing with mussel embryos, Mytilus galloprovincialis) and two acute methods (amphipod survival with Eohaustorius estuarius and L. plumulosus) were used to test split sediment samples from stations in California. The test with Amphiascus proved to be the most sensitive sublethal test and the most sensitive overall, identifying 90% of the stations as toxic. The Leptocheirus 10-d test was the most sensitive of the acute tests, identifying 60% of the stations as toxic. In general, the sublethal tests were not more sensitive to sediments than the acute tests, with the sublethal tests finding an average of 35% of the stations to be toxic while the acute found 44%. Of the sublethal tests, only the Amphiascus endpoints and Neanthes growth significantly (por= 0.05) correlated with sediment chemical concentrations. Poor correspondence occurred between the toxicity endpoints and the indicators of benthic community condition. Differences in test characteristics such as mode of exposure, species-specific contaminant sensitivity, changes in contaminant bioavailability, and influence of noncontaminant stressors on the benthos may have been responsible for variation in response among the tests and low correspondence with benthic community condition. The influence of these factors cannot be easily predicted, underscoring the need to use multiple toxicity methods, in combination with other lines of evidence, to provide an accurate and confident assessment of sediment toxicity.