This study assessed effectiveness of regulations reducing environmental butyltin concentrations in Southern Chesapeake Bay over the 1999-2021 period. Water column monitoring of the Elizabeth River from 1999 to 2006 demonstrated decreasing TBT from 2003 to 2006 (average >1 ng/L at most stations) to <1 ng L- 1 by 2019 but with higher concentrations of degradation products DBT and MBT. TBT degrades to DBT and MBT within sediments, and releases degradation products over time. TBT induces imposex in exposed gastropods. Collections of the rapa whelk in 1999-2001 found TBT levels in female, imposex, and male whelks with median TBT concentrations of 10.5, 11.5, and 70 ng/g respectively. Collections in 2021 were below the TBT detection limit (<4.7 ng/g) and showed reduced incidence of imposex. The decrease of both TBT to below EPA water quality standard (7.4 ng/g) and observed gastropod imposex over the 1999-2021 period provides evidence that regulations limiting TBT use have been successful.

Tainting of shellfish by polyaromatic hydrocarbons (PAHs) following an oil spill poses possible health risks as well as socioeconomic impacts. Traditional screening approaches for evaluating PAH contamination have limitations that can prevent timely, objective spill response decisions. The objective of this study was to investigate the relationship between PAH concentrations measured in the oyster, Crassostrea virginica, interstitial fluid using a rapid antibody-based biosensor method, with PAH concentrations in oyster tissues determined using conventional gas chromatography-mass spectrometry analysis. To accomplish this objective, bioconcentration tests were performed to simulate oil spill exposures using a crude and heavy fuel oil containing different PAH compositions. This design allowed both the PAH concentration and composition in water and, subsequently, accumulated by oysters to be varied over time. Oysters sampled during uptake and depuration phases were analyzed using biosensor and conventional analysis methods to generate comparative data. Results indicated that biosensor measurements of oysters captured the kinetics of PAH accumulation during uptake and depuration phases. Further, significant positive correlations were observed between biosensor interstitial fluid and lipid-normalized PAH tissue concentrations. However, quantitative predictions appear to be modulated by the contamination source and target analyte list for tissue analysis. Thus, the biosensor can be applied for rapidly evaluating relative PAH contamination between biota samples and offers a promising new analytical tool for oil spill monitoring and fisheries management contexts. A generic model was also developed from study and literature data to predict PAH half-lives from bivalve tissues. These predictions can help inform field monitoring of shellfish and estimate recovery times required to achieve pre-spill conditions. Rapid detection of oyster tainting following an oil spill can greatly enhance response decisions.Oysters exposed to Water Accommodated Fractions (WAFs) from two oils were analyzed using an antibody based biosensor and traditional GC-MS to evaluate uptake and depuration rates of PAHs.Significant positive correlations were observed between biosensor interstitial fluid and lipid-normalized PAH tissue concentrations.A generic model was developed from study and literature data to predict PAH half-lives from bivalve tissues.

Bivalve mollusks including oysters have low metabolic potential and are therefore susceptible to accumulating high levels of lipophilic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs). Human exposure to PAHs via consumption of this important commercial shellfish can be a serious public health concern in areas where high PAH contamination exists. Previous PAH immunohistochemical studies have been limited to laboratory‐based exposures focusing on one or a few individual PAH compounds. To date, such studies have yet to explore PAH accumulation in oysters, known to have some of the highest levels of PAHs across different food products. Using a monoclonal antibody selective for a range of three‐ to five‐ring PAHs, we present a method to detect and localize complex mixtures of PAHs in oyster tissues via fluorescent immunohistochemistry. Observed immunofluorescence intensity followed a similar trend as measured levels of PAHs in oyster interstitial fluid from PAH‐contaminated sites and oysters exposed to the water accommodated fraction of crude oil. This method will be valuable in understanding internal partitioning mechanisms of PAH‐exposed oysters and will have important applications in studies on PAH distribution in the tissues of additional organisms for environmental, medical, or veterinary purposes. Environ Toxicol Chem 2023;42:475–480. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Crassostrea virginica is a well-established bivalve species for biomonitoring persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAH) in aquatic environments. Differing biomonitoring methods employing either wild oysters inhabiting sites of interest or naïve cultured oysters deployed to sites for extended periods can be used for site evaluations. However, important differences in total contaminant concentrations accumulated have been observed between the wild and transplanted groups. Furthermore, although rearing cultured triploid oysters is widely popular in commercial farming, the difference in contaminant bioaccumulation potential between triploid and diploid cultured oysters is vastly understudied, particularly for organic contaminants such as PAH. This study explores differences in PAH kinetics between transplanted triploid and diploid cultured oysters and wild oysters at a PAH-impacted site during a 6-week field exposure study using novel immunological techniques: antibody-based biosensor technology and immunofluorescence visualization. Conventional chemical analysis of oyster tissue was also conducted for comparison. While differences were observed in the oyster interstitial fluid between the wild and transplanted oysters throughout the study, whole tissue analysis revealed differing trends at each time point. Our findings suggest that insufficient equilibration time may contribute to the differences observed between groups. Furthermore, when combined with visual evidence via immunofluorescence, internal partitioning of contaminants may be an important determinant for total concentrations measured. A better understanding of the differences observed between wild and transplanted oyster groups is necessary for improved biomonitoring. Our study highlights the value in employing novel immunological techniques to explore possible mechanisms driving these differences.

Conventional PAH analytical methods are time-consuming and expensive, limiting their utility in time sensitive events (i.e. oil spills and floods) or for widespread environmental monitoring. Unreliable and inefficient screening methods intended to prioritize samples for more extensive analyses exacerbate the issue. Antibody-based biosensor technology was implemented as a quantitative screening method to measure total PAH concentration in adult oysters (Crassostrea virginica) - a well-known bioindicator species with ecological and commercial significance. Individual oysters were analyzed throughout the historically polluted Elizabeth River watershed (Virginia, USA). Significant positive association was observed between biosensor and GC-MS measurements that persisted when the method was calibrated for different regulatory subsets of PAHs. Mapping of PAH concentrations in oysters throughout the watershed demonstrates the utility of this technology for environmental monitoring. Through a novel extension of equilibrium partitioning, biosensor technology shows promise as a cost-effective analysis to rapidly predict whole animal exposure to better assess human health risk as well as improve monitoring efforts.

Decades of research have shown that the concentration of freely dissolved PAH (Cfree) in sediment correlates with PAH bioavailability and toxicity to aquatic organisms. Passive sampling techniques and models have been used for measuring and predicting Cfree, respectively, but these techniques require weeks for analytical chemical measurements and data evaluation. This study evaluated the performance of a portable, field-deployable antibody-based PAH biosensor method that can provide measurements of PAH Cfree within a matter of minutes using a small volume of mechanically-extracted sediment porewater. Four sediments with a wide range of PAHs (ΣPAH 2.4 to 307 mg/kg) derived from petroleum, creosote, and mixed urban sources, were analyzed via three methods: 1) bulk chemistry analysis; 2) ex situ sediment passive sampling; and 3) biosensor analysis of mechanically-extracted sediment porewater. Mean ΣPAH Cfree determined by the biosensor for the four sediments (3.1 to 55 µg/L) were within a factor of 1.1 (on average) compared to values determined by the passive samplers (2.0 to 52 µg/L). All mean values differed by a factor of 3 or less. The biosensor was also useful in identifying sediments that are likely to be non-toxic to benthic invertebrates. In two of the four sediments, biosensor results of 20 and 55 µg/L exceeded a potential risk-based screening level of 10 µg/L, indicating toxicity could not be ruled out. PAH Toxic Units (ΣTU) measured in these two sediments using the passive sampler Cfree results were also greater than the ΣTU threshold of 1 (6.7 and 5.8, respectively), confirming the conclusions reached with the biosensor. In contrast, the other two sediments were identified as non-toxic by both the biosensor (3.1 and 4.3 µg/L) and the passive sampler (ΣTUs of 0.34 and 0.039). These results indicate that the biosensor is a promising tool for rapid screening of sediments potentially-impacted with PAHs.

Background: Given the time and monetary costs associated with traditional analytical chemistry, there remains a need to rapidly characterize environmental samples for priority analysis, especially within disaster research response (DR2). As PAHs are both ubiquitous and occur as complex mixtures at many National Priority List sites, these compounds are of interest for post-disaster exposures. Objective: This study tests the field application of the KinExA Inline Biosensor in Galveston Bay and the Houston Ship Channel (GB/HSC) and in the Elizabeth River, characterizing the PAH profiles of these region's soils and sediments. To our knowledge, this is the first application of the biosensor to include soils. Methods: The biosensor enables calculation of total free PAHs in porewater (C free), which is confirmed through gas chromatography-mass spectrometry (GC-MS) analysis. To determine potential risk of the collected soils the United States Environmental Protection (USEPA) Agency's Regional Screening Level (RSL) Calculator is used along with the USEPA Region 4 Ecological Screening Values (R4-ESV) and Refined Screening Values (R4-RSV). Results: Based on GC-MS results, all samples had PAH-related hazard indices below 1, indicating low noncarcinogenic risks, but some samples exceeded screening levels for PAH-associated cancer risks. Combining biosensor-based C free with Total Organic Carbon yields predictions highly correlated (r > 0.5) both with total PAH concentrations as well as with hazard indices and cancer risks. Additionally, several individual parent PAH concentrations in both the GB/HSC and Elizabeth River sediments exceeded the R4- ESV and R4-RSV values, indicating a need for follow-up sediment studies. Conclusions: The resulting data support the utility of the biosensor for future DR2 efforts to characterize PAH contamination, enabling preliminary PAH exposure risk screening to aid in prioritization of environmental sample analysis.

Manganese (Mn) is a hypoxic reactive metal commonly found in marine sediments. Under hypoxic conditions the metal becomes fully reduced to Mn2+ and is biologically available to the benthic community for uptake. Mn is also a potent neurotoxin and it may play a role in the etiology of idiopathic blindness that has been observed in American lobsters. An acute exposure study was designed to expose American lobster, Homarus americanus, to 0, 20, 80, 150, and 300 mg L-1 (ppm) for 96 hs to explore disparities in Mn accumulation among several tissues: optic nerve, brain, hepatopancreas, muscle, hemolymph, gill, and exoskeleton. These concentrations were based on realistic pore-water concentrations (20 mg L-1), high sediment concentrations (80 mg L-1), and unrealistically high concentrations to determine lethality (150 and 300 mg L-1). A positive correlation between Mn accumulation and exposure concentration was observed in all tissues examined. In the internal tissues, manganese concentrations showed a high affinity towards brain, optic nerve, and hemolymph. In the exoskeleton and gills, Mn concentrations were also high, possibly because of internal uptake as well as external adsorption. Concentrations of Mn in tissues from the acute exposure study followed the accumulation pattern: hemolymph > gill > exoskeleton > optic nerve > brain > hepatopancreas = muscle. A long-term exposure study lasting seven weeks was designed to investigate the potential link between high Mn exposure and idiopathic blindness, a condition that affects an estimated 50 % of the adult American lobster population off Southern New England (SNE), USA. A comparison of these exposure studies showed evidence of time-dependent Mn accumulation in brain, muscle, exoskeleton, and gill tissue. Although the relationship between Mn exposure and blindness was not apparent, there was a modest trend in the development of blindness (Chi-square, p = 0.102) in animals exposed to a high concentration (150 mg L-1) of the metal. With no mortalities occurring in the acute study and only one mortality in the long-term study, it is highly unlikely that Mn is acutely toxic to American lobsters at environmentally relevant concentrations. Its potential role in idiopathic blindness remains to be determined.

Although the complexity of contaminant mixtures in sediments can confound the identification of causative agents of adverse biological response, understanding the contaminant(s) of primary concern at impacted sites is critical to sound environmental management and remediation. In the present study, a stock mixture of 18 polycyclic aromatic hydrocarbon (PAH) compounds was prepared to reflect the variety and relative proportions of PAHs measured in surface sediment samples collected from discrete areas of a historically contaminated industrial estuary. This site‐specific PAH stock mixture was spiked into nontoxic in‐system and out‐of‐system field‐collected reference sediments in dilution series spanning the range of previously measured total PAH concentrations from the region. Spiked sediments were evaluated in 10‐d Leptocheirus plumulosus tests to determine whether toxicity in laboratory‐created PAH concentrations was similar to the toxicity found in field‐collected samples with equivalent PAH concentrations. The results show that toxicity of contaminated sediments was not explained by PAH exposure, while indicating that toxicity in spiked in‐system (fine grain, high total organic carbon [TOC]) and out‐of‐system (course grain, low TOC) sediments was better explained by porewater PAH concentrations, measured using an antibody‐based biosensor that quantified 3‐ to 5‐ring PAHs, than total sediment PAH concentrations. The study demonstrates the application of site‐specific spiking experiments to evaluate sediment toxicity at sites with complex mixtures of multiple contaminant classes and the utility of the PAH biosensor for rapid sediment‐independent porewater PAH analysis. Environ Toxicol Chem 2018;37:893–902. © 2017 SETAC

The imposition of male sexual characteristics onto the female (imposex) is present in wild populations of the non-native veined rapa whelk (Rapana venosa) in Chesapeake Bay, USA but does not appear to compromise reproductive function. Cultured whelks were used to test two hypotheses: (1) Observed imposex metrics will be similar to tributyltin (TBT) water concentrations at each of three sites; (2) Male and imposex/female whelks from the same site will have similar TBT body burdens. Cultured 2-year-old whelks were transplanted to three field sites in the York River, USA at the onset of their second reproductive season. Transplant site mean TBT water concentrations ranged from 1.4 ± 0.77 to 64.2 ± 57.8 ng l−1. Imposex incidence was 100% after 28 weeks with an observed M:F:IF ratio of 81:0:92 across all sites. Imposex stages (median vas deferens scale index = 4) and reproductive output were similar across sites. The imposex severity (IS = penis length/shell length) increased with increasing TBT concentrations. The relative penis length (RPLI) and relative penis size (RPSI) indices were positively related to site-specific TBT levels. Male whelks accumulated significantly higher TBT concentrations than female whelks at the site with the highest TBT concentration. Mean TBT concentrations in whelk egg capsules were significantly higher than concentrations in male or female whelk tissue. Egg capsule deposition provides a depuration mechanism for female whelks to reduce body burden of lipophilic TBT. Sex, season and reproductive status should be considered when using gastropod bioaccumulation to monitor TBT effects.

The notion of state for a system is prevalent in the quantitative sciences and refers to the minimal system summary sufficient to describe the time evolution of the system in a self-consistent manner. This is a prerequisite for a principled understanding of the inner workings of a system. Owing to the complexity of intracellular processes, experimental techniques that can retrieve a sufficient summary are beyond our reach. For the case of stochastic biomolecular reaction networks, we show how to convert the partial state information accessible by experimental techniques into a full system state using mathematical analysis together with a computational model. This is intimately related to the notion of conditional Markov processes and we introduce the posterior master equation and derive novel approximations to the corresponding infinite-dimensional posterior moment dynamics. We exemplify this state reconstruction approach using both in silico data and single-cell data from two gene expression systems in Saccharomyces cerevisiae, where we reconstruct the dynamic promoter and mRNA states from noisy protein abundance measurements.

.•.•.. · • • • • • • • • • • • • • • • • • • • • • • • · · • . · ..•......... viii CHAPTER I GENERAL INTRODUCTION. •••••••••••••••••••••••••• 2 CHAPTER II XENOBIOTIC COMPOUNDS IN BLUE CRABS FROM THE ELIZABETH RIVER. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o Introduction .• · · · · · · · · · · · · · · · · · · · · · · · · · ..........•... 10 Materials and Methods. .. • • • • • • • • • • • • • • • • .. · .......... 10 Results •.... · · · · · • · • · · · · · · · · · · · · • · · · · · · · · · · · · ........ 1 7 Discussion .. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · .......... 2 6 CHAPTER III INFLUENCE OF PAH IN FIELD ECDYSIS EXPOSED ON THE ACCUMULATION OF CRABS • ••••••••••••••••• 3 3 Introduction .•.. • · · · · • · • · · • · · • • · · · · • · · · · · • • · ......... 3 3 Materials and Methods •......•......•................. 33 Field Experiment .•.•.....•...•.••...•........... 3 3 Laboratory Analysis ...............•............. 35 statistical Analysis .....•........•.••..•....... 36 Results •..•. ·····•···•·•·•·••··•·····•·•·········· ... 37 Discussion ... ······•···········•················· .... 41 CHAPTER IV CONCLUSIONS ..•.•.•...••...................... 4 6 LITERATURE CITED. · • • • • · • · · · · · · · · • · · • · · · · · · · · · · · · · · · · • • · · · . 4 8 VITA •.••..•..•.... · • • • • · · · • · • · · · · • · • · · · · · · · · • · · · · · · • • • · ... 55

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 and 31μg/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 0.2μg/L. Furthermore, the analyses only required 10min 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 development of monoclonal antibodies (mAb) with affinity to small molecules can be a time-consuming process. To evaluate shortening the time for mAb production, we examined mouse antisera at different time points post-immunization to measure titer and to evaluate the affinity to the immunogen PBA (pyrene butyric acid). Fusions were also conducted temporally to evaluate antibody production success at various time periods. We produced anti-PBA antibodies 7 weeks post-immunization and selected for anti-PAH reactivity during the hybridoma screening process. Moreover, there were no obvious sensitivity differences relative to antibodies screened from a more traditional 18-week schedule. Our results demonstrate a more time efficient immunization strategy for anti-PAH antibody development that may be applied to other small molecules.

It remains unclear whether causal, rather than merely correlational, relationships in molecular networks can be inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge, which focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective, and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess inferred molecular networks in a causal sense.

Directional cell growth requires that cells read and interpret shallow chemical gradients, but how the gradient directional information is identified remains elusive. We use single-cell analysis and mathematical modeling to define the cellular gradient decoding network in yeast. Our results demonstrate that the spatial information of the gradient signal is read locally within the polarity site complex using double-positive feedback between the GTPase Cdc42 and trafficking of the receptor Ste2. Spatial decoding critically depends on low Cdc42 activity, which is maintained by the MAPK Fus3 through sequestration of the Cdc42 activator Cdc24. Deregulated Cdc42 or Ste2 trafficking prevents gradient decoding and leads to mis-oriented growth. Our work discovers how a conserved set of components assembles a network integrating signal intensity and directionality to decode the spatial information contained in chemical gradients.

리들리 스콧(Ridley Scott)의 선견지명이 있는 SF영화, 블레이드 러너(Blade Runner, 1982)가 처음 나온지 33년이 지난 지금, 여전히 이 영화는 SF영화 장르에서 ‘다른 것’으로써의 ‘에일리언’ 개념의 사이버펑크 미학적이며 주제와 관련된 중요한 변화로 여겨지고 있다. 이 영화의 면밀한 분석을 통해서, 인간과 기계의 경계를 붕괴하는 새로운 주체성을 창조하는 인간과 테크놀로지의 결합을 설명하고 있는 기술적으로 디자인된 독립체를,“복제”라는 개념을 통해 이 영화의 디에게시스 안에서 인간과 테크놀로지의 친밀한 결합에 관한 설명을 재연구한다. 또한 이 재고찰은 영화가 현재 우리가 사는 글로벌 정보 시대에서 테크놀로지와 우리의 관계를 어떻게 반영하고 있는지에 관해서도 연구하고 있다.