Publications by authors named "Jeanette M Rotchell"

48 Publications

The Uptake of Sporopollenin Exine Capsules and Associated Bioavailability of Adsorbed Oestradiol in Selected Aquatic Invertebrates.

Bull Environ Contam Toxicol 2021 Nov 30;107(5):876-882. Epub 2021 Aug 30.

Department of Biological and Marine Sciences, University of Hull, Cottingham Rd, Hull, HU6 7RX, UK.

Lycopodium clavatum sporopollenin exine capsules (SpECs) are known to both adsorb and absorb chemicals. The aim of the present work was to determine whether oestradiol (E2) is 'bioavailable' to bioindicator species, either pre-adsorbed to, or in the presence of, SpECs. SpEC uptake was confirmed for Daphnia magna and Dreissena bugensis. E2 levels varied among treatments for Caenorhabditis elegans though there was no relationship to SpEC load. E2 was not detected in D. bugensis tissues. Expression changes of general stress and E2-specific genes were measured. For C. elegans, NHR-14 expression suggested that SpECs modulate E2 impacts, but not general health responses. For D. magna, SpECs alone and with E2 changed Vtg1 and general stress responses. For D. bugensis, SpECS were taken up but no E2 or change in gene expression was detected after exposure to E2 and/or SpECs. The present study is the first to investigate SpECs and bound chemical dynamics.
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http://dx.doi.org/10.1007/s00128-021-03364-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8556174PMC
November 2021

Susceptibility of polar cod (Boreogadus saida) to a model carcinogen.

Mar Environ Res 2021 Aug 27;170:105434. Epub 2021 Jul 27.

Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics UiT the Arctic University of Norway, 9037, Tromsø, Norway.

Studies that aim to characterise the susceptibility of the ecologically relevant and non-model fish polar cod (Boreogadus saida) to model carcinogens are required. Polar cod were exposed under laboratory conditions for six months to control, 0.03 μg BaP/g fish/week and 0.3 μg BaP/g fish/week dietary benzo(a)pyrene (BaP), a reference carcinogen. The concentrations of the 3-OH-BaP bile metabolite and transcriptional responses of genes involved in DNA adduct recognition (xpc), helicase activity (xpd), DNA repair (xpf, rad51) and tumour suppression (tp53) were assessed after 0, 1, 3 and 6 months of exposure, alongside body condition indexes (gonadosomatic index, hepatosomatic index and condition factor). Micronuclei and nuclear abnormalities in blood and spleen, and liver histopathological endpoints were assessed at the end of the experiment. Fish grew steadily over the whole experiment and no mortality was recorded. The concentrations of 3-OH-BaP increased significantly after 1 month of exposure to the highest BaP concentration and after 6 months of exposure to all BaP concentrations showing the biotransformation of the mother compound. Nevertheless, no significant induction of gene transcripts involved in DNA damage repair or tumour suppression were observed at the selected sampling times. These results together with the absence of chromosomal damage in blood and spleen cells, the subtle increase in nuclear abnormalities observed in spleen cells and the low occurrence of foci of cellular alteration suggested that the exposure was below the threshold of observable effects. Taken together, the results showed that polar cod was not susceptible to carcinogenesis using the BaP exposure regime employed herein.
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http://dx.doi.org/10.1016/j.marenvres.2021.105434DOI Listing
August 2021

Consequences of combined exposure to thermal stress and the plasticiser DEHP in Mytilus spp. differ by sex.

Mar Pollut Bull 2021 Sep 16;170:112624. Epub 2021 Jun 16.

Department of Biological and Marine Sciences, University of Hull, Hull HU6 7RX, United Kingdom. Electronic address:

Little is known about the combined effect of environmental factors and contaminants on commercially important marine species, and whether this effect differs by sex. In this study, blue mussels were exposed for seven days to both single and combined stressors (i.e., +3 °C elevated temperature and two environmentally relevant concentrations of the plastic softener DEHP, 0.5 and 50 μg/l) in a factorial design. Males were observed to be more sensitive to high temperature, demonstrated by the significant increase in out-of-season spawning gonads and higher gene expression of the antioxidant catalase and the estrogen receptor genes. On the other hand, while the gametogenesis cycle in females was more resilient than in males, DEHP exposure altered the estrogen-related receptor gene expression. We show that the combined stressors DEHP and increased temperature, in environmentally relevant magnitudes, have different consequences in male and female mussels, with the potential to impact the timing and breeding season success in Mytilus spp.
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http://dx.doi.org/10.1016/j.marpolbul.2021.112624DOI Listing
September 2021

Where are we? Towards an understanding of the selective accumulation of microplastics in mussels.

Environ Pollut 2021 Oct 8;286:117543. Epub 2021 Jun 8.

Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf, College of Marine Sciences, Beibu Gulf University, Qinzhou, 535011, China.

Mussels are suggested as bioindicators of marine microplastic pollution. However, they are selective in regards to accumulation of microplastics. To make studies more targeted and comparable, ultimately helping to determine the suitability of the mussel as a bioindicator species for microplastic exposure, we review the published literature that has directly or indirectly demonstrated particle selection in mussels. The reported difference between microplastic levels in mussel tissues and environmental matrices provides evidence for their selective uptake characteristics. Both the organ-specific fate characteristics of microplastics, and the different movement patterns of microplastics in the same organ, show that selective translocation processes take place. The selective elimination is reflected in multiple aspects which include (1) the different characteristics of microplastics in excretion and mussel body; (2) the different retention time of various microplastics in mussels; and (3) the tissue-specific change in the numbers of microplastics during the depuration process. This selectivity is affected by the characteristics of the microplastics, the environmental, or laboratory exposure concentrations, feeding status, and other factors. There are still many research gaps and contradictory viewpoints in this field due to this complexity. The current methodology needs improvement and a breakthrough in standardization.
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http://dx.doi.org/10.1016/j.envpol.2021.117543DOI Listing
October 2021

Microplastic Contamination of Seafood Intended for Human Consumption: A Systematic Review and Meta-Analysis.

Environ Health Perspect 2020 12 23;128(12):126002. Epub 2020 Dec 23.

Department of Biological and Marine Sciences, University of Hull, Hull, UK.

Background: Microplastics (MPs) have contaminated all compartments of the marine environment including biota such as seafood; ingestion from such sources is one of the two major uptake routes identified for human exposure.

Objectives: The objectives were to conduct a systematic review and meta-analysis of the levels of MP contamination in seafood and to subsequently estimate the annual human uptake.

Methods: MEDLINE, EMBASE, and Web of Science were searched from launch (1947, 1974, and 1900, respectively) up to October 2020 for all studies reporting MP content in seafood species. Mean, standard deviations, and ranges of MPs found were collated. Studies were appraised systematically using a bespoke risk of bias (RoB) assessment tool.

Results: Fifty studies were included in the systematic review and 19 in the meta-analysis. Evidence was available on four phyla: mollusks, crustaceans, fish, and echinodermata. The majority of studies identified MP contamination in seafood and reported MP content , with 26% of studies rated as having a high RoB, mainly due to analysis or reporting weaknesses. Mollusks collected off the coasts of Asia were the most heavily contaminated, coinciding with reported trends of MP contamination in the sea. According to the statistical summary, MP content was in mollusks, in crustaceans, in fish, and in echinodermata. Maximum annual human MP uptake was estimated to be close to 55,000 MP particles. Statistical, sample, and methodological heterogeneity was high.

Discussion: This is the first systematic review, to our knowledge, to assess and quantify MP contamination of seafood and human uptake from its consumption, suggesting that action must be considered in order to reduce human exposure via such consumption. Further high-quality research using standardized methods is needed to cement the scientific evidence on MP contamination and human exposures. https://doi.org/10.1289/EHP7171.
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http://dx.doi.org/10.1289/EHP7171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757379PMC
December 2020

A comparison of microplastic contamination in freshwater fish from natural and farmed sources.

Environ Sci Pollut Res Int 2021 Mar 19;28(12):14488-14497. Epub 2020 Nov 19.

Department of Biological and Marine Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.

Contamination of aquatic systems mainly by urbanization and poor sanitation, deficient or lack of wastewater treatments, dumping of solid residues, and run off has led to the presence of particles, including manmade polymers, in tissues of many marine and freshwater species. In this study, the prevalence of microplastics (MPs) in freshwater fish from farmed and natural sources was investigated. Oreochromis niloticus from aquaculture farms in the Huila region in Colombia, and two local species (Prochilodus magdalenae and Pimelodus grosskopfii), naturally present in surface waters were sampled. Of the particles identified, fragments were the predominant type in the three tissue types (stomach, gill, and flesh) derived from farmed and natural fishes. MicroFT-IR spectroscopy was conducted on 208 randomly selected samples, with 22% of particles identified as MPs based on spectra with a match rate ≥ 70%. A total of 53% of identified particles corresponded to cellophane/cellulose, the most abundant particle found in all fish. Not all fish contained MPs: 44% of Oreochromis farmed fish contained MPs, while 75% of natural source fish contained MPs in any of its tissues. Overall, polyethylene terephthalate (PET), polyester (PES), and polyethylene (PE) were the prevalent MPs found in the freshwater fish. A broader variety of polymer types was observed in farmed fish. The edible flesh part of fish presented the lower prevalence of MPs compared to gill and stomach (gut), with gut displaying a higher frequency and diversity of MPs. This preliminary study suggests that the incidence and type of MPs varies in farmed verses natural fish sources as well as across different tissue types, with significantly less detected within the edible flesh tissues compared with stomach and gill tissues.
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http://dx.doi.org/10.1007/s11356-020-11605-2DOI Listing
March 2021

Microplastic contamination of drinking water: A systematic review.

PLoS One 2020 31;15(7):e0236838. Epub 2020 Jul 31.

Department of Biological and Marine Sciences, University of Hull, Hull, United Kingdom.

Background: Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.

Objective: To undertake a systematic review of MP contamination of drinking water and estimate quantitative exposures.

Methods: The protocol for the systematic review employed has been published in PROSPERO (PROSPERO 2019, Registration number: CRD42019145290). MEDLINE, EMBASE and Web of Science were searched from launch to the 3rd of June 2020, selecting studies that used procedural blank samples and a validated method for particle composition analysis. Studies were reviewed within a narrative analysis. A bespoke risk of bias (RoB) assessment tool was used.

Results: 12 studies were included in the review: six of tap water (TW) and six of bottled water (BW). Meta-analysis was not appropriate due to high statistical heterogeneity (I2>95%). Seven studies were rated low RoB and all confirmed MP contamination of drinking water. The most common polymers identified in samples were polyethylene terephthalate (PET) and polypropylene (PP), Methodological variability was observed throughout the experimental protocols. For example, the minimum size of particles extracted and analysed, which varied from 1 to 100 μm, was seen to be critical in the data reported. The maximum reported MP contamination was 628 MPs/L for TW and 4889 MPs/L for BW, detected in European samples. Based on typical consumption data, this may be extrapolated to a maximum yearly human adult uptake of 458,000 MPs for TW and 3,569,000 MPs for BW.

Conclusions: This is the first systematic review that appraises the quality of existing evidence on MP contamination of drinking water and estimates human exposures. The precautionary principle should be adopted to address concerns on possible human health effects from consumption of MPs. Future research should aim to standardise experimental protocols to aid comparison and elevate quality.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236838PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7394398PMC
September 2020

A preliminary analysis of microplastics in edible versus non-edible tissues from seafood samples.

Environ Pollut 2020 Aug 27;263(Pt A):114452. Epub 2020 Mar 27.

Department of Biological and Marine Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, United Kingdom. Electronic address:

Plastics have been widely reported to be present in the environment yet there are still many questions regarding the extent of this and the impacts these may have on both the environment and human health. The purpose of this investigation is to determine levels of micro and mesoplastic (MP), in the 1-5000 μm range, in commercially important species of finfish and shellfish. Additionally, to determine and compare the relative MP levels in edible versus non-edible tissues, and consider the wider implications in terms of human health concerns with a preliminary risk identification approach. For several fish species, samples taken from typically non-edible (gills, digestive system) and edible (muscle) flesh, and were analysed separately. Scallops, where all tissues are edible, were analysed whole. Significant differences were observed in the number of particles isolated from the finfish gills and digestive tissues relative to the control samples, but not in the edible flesh. For scallops, the abundance of particles in the Scottish samples did not vary significantly from the control, while the Patagonian scallops displayed significantly higher numbers of MPs. Characterisation of MPs by FTIR microscopy found that 16-60% (depending on species) were polyethylene terephthalate (PET) and polyethylene (PE) in origin. The risk identification results validate MPs as an emerging risk in the food chain and establish seafood as a vector for the exposure and uptake of MPs through the ingestion route for humans. Levels of MPs in seafood, and a direct link to the human food chain, suggests that their quantification be included as one food safety measure.
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http://dx.doi.org/10.1016/j.envpol.2020.114452DOI Listing
August 2020

Influence of light and temperature cycles on the expression of circadian clock genes in the mussel Mytilus edulis.

Mar Environ Res 2020 Jul 23;159:104960. Epub 2020 Mar 23.

Department of Biological and Marine Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, United Kingdom. Electronic address:

Clock genes and environmental cues regulate essential biological rhythms. The blue mussel, Mytilus edulis, is an ecologically and economically important intertidal bivalve undergoing seasonal reproductive rhythms. We previously identified seasonal expression differences in M. edulis clock genes. Herein, the effects of light/dark cycles, constant darkness, and daily temperature cycles on the circadian expression patterns of such genes are characterised. Clock genes Clk, Cry1, ROR/HR3, Per and Rev-erb/NR1D1, and Timeout-like, show significant mRNA expression variation, persisting in darkness indicating endogenous control. Rhythmic expression was apparent under diurnal temperature cycles in darkness for all except Rev-erb. Temperature cycles induced a significant expression difference in the non-circadian clock-associated gene aaNAT. Furthermore, Suppression Subtractive Hybridisation (SSH) was used to identify seasonal genes with potential links to molecular clock function and revealed numerous genes meriting further investigation. Understanding the relationship between environmental cues and molecular clocks is crucial in predicting the outcomes of environmental change on fundamental rhythmic processes.
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http://dx.doi.org/10.1016/j.marenvres.2020.104960DOI Listing
July 2020

Silver Nanoparticles in Zebrafish () Embryos: Uptake, Growth and Molecular Responses.

Int J Mol Sci 2020 Mar 9;21(5). Epub 2020 Mar 9.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.

Silver nanoparticles (AgNPs) are widely used in commercial applications as antimicrobial agents, but there have recently been increasing concerns raised about their possible environmental and health impacts. In this study, zebrafish embryos were exposed to two sizes of AgNP, 4 and 10 nm, through a continuous exposure from 4 to 96 h post-fertilisation (hpf), to study their uptake, impact and molecular defense responses. Results showed that zebrafish embryos were significantly impacted by 72 hpf when continuously exposed to 4 nm AgNPs. At concentrations above 0.963 mg/L, significant in vivo uptake and delayed yolk sac absorption was evident; at 1.925 mg/L, significantly reduced body length was recorded compared to control embryos. Additionally, 4 nm AgNP treatment at the same concentration resulted in significantly upregulated 4 () and () mRNA expression in exposed embryos 96 hpf. In contrast, no significant differences in terms of larvae body length, yolk sac absorption or gene expression levels were observed following exposure to 10 nm AgNPs. These results demonstrated that S4 AgNPs are available for uptake, inducing developmental (measured as body length and yolk sac area) and transcriptional (specifically and ) perturbations in developing embryos. This study suggests the importance of particle size as one possible factor in determining the developmental toxicity of AgNPs in fish embryos.
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http://dx.doi.org/10.3390/ijms21051876DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7084859PMC
March 2020

PVC Does Not Influence Cadmium Uptake or Effects in the Mussel (Mytilus edulis).

Bull Environ Contam Toxicol 2020 Mar 20;104(3):315-320. Epub 2020 Jan 20.

School of Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.

Microplastics have become a global concern in recent years. In this study, we studied (i) whether the presence of polyvinyl chloride (PVC) microparticles may affect cadmium (Cd) uptake in mussel (Mytilus edulis); and (ii) the biological effects of PVC microparticles exposure alone or in combination with Cd. Significant Cd uptake in digestive gland was observed following Cd exposure. However, PVC did not significantly increase Cd uptake compared with Cd alone treatment. In terms of biological impacts, significantly lower neutral red retention (NRR) time and elevated expression of Metallothionein isoform 20-IV (MT-20) were observed in mussels exposed to Cd alone, or combined with microplastics, yet there was no significant difference between them. catalase (CAT) expression only showed a significant increase in mussels exposed to Cd alone. This work provides an insight into the relationship on resulting biological impacts between these two contaminants.
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http://dx.doi.org/10.1007/s00128-020-02789-xDOI Listing
March 2020

Spatial and temporal occurrence of pharmaceuticals in UK estuaries.

Sci Total Environ 2019 Aug 16;678:74-84. Epub 2019 Apr 16.

School of Environmental Sciences, University of Hull, Cottingham Road, Hull HU6, 7RX, United Kingdom of Great Britain and Northern Ireland.

There is a lack of data on the occurrence of pharmaceuticals in estuaries worldwide, with little understanding of their temporal and spatial variations globally. Ibuprofen, paracetamol, diclofenac, trimethoprim and citalopram were measured in twelve estuaries in the UK. Initially, these compounds were monitored in the Humber Estuary, where samples were taken every two months over a twelve month period in order to assess their spatial and temporal variations. Ibuprofen was found at some of the highest concentrations ever measured in an estuary globally (18-6297 ng l), with paracetamol also measured at relatively high concentrations (4-917 ng l) in comparison to the other compounds. In terms of spatial distribution, a pattern was observed where the highest concentrations were found at a site at which wastewater is discharged, whilst compound concentrations were often lower upstream and downstream of this site. The downstream profile of pharmaceuticals differed temporally with concentrations highest downstream when input from wastewater effluent was highest. Eleven further estuaries were sampled around the UK in order to put the occurrence of pharmaceuticals in the Humber Estuary into a wider context. Pharmaceutical concentrations in the other estuaries sampled were <210 ng l but, again, ibuprofen and paracetamol were found at concentrations higher than other compounds, whereas diclofenac and citalopram were absent in many estuaries. The Humber, which is the receiving environment for the sewage effluent of approximately 20% (13.6 million people) of the population of England, was observed to have the highest overall concentration of pharmaceuticals in contrast to the other estuaries sampled, thereby representing a worst case scenario for pharmaceutical pollution.
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http://dx.doi.org/10.1016/j.scitotenv.2019.04.182DOI Listing
August 2019

Using mussel as a global bioindicator of coastal microplastic pollution.

Environ Pollut 2019 Jan 9;244:522-533. Epub 2018 Oct 9.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China. Electronic address:

The ubiquity and high bioavailability of microplastics have an unknown risk on the marine environment. Biomonitoring should be used to investigate biotic impacts of microplastic exposure. While many studies have used mussels as indicators for marine microplastic pollution, a robust and clear justification for their selection as indicator species is still lacking. Here, we review published literature from field investigations and laboratory experiments on microplastics in mussels and critically discuss the suitability and challenges of mussels as bioindicator for microplastic pollution. Mussels are suitable bioindicator for microplastic pollution because of their wide distribution, vital ecological niches, susceptibility to microplastic uptake and close connection with marine predators and human health. Field investigations highlight a wide occurrence of microplastics in mussels from all over the world, yet their abundance varies enormously. Problematically, these studies are not comparable due to the lack of a standardized approach, as well as temporal and spatial variability. Interestingly, microplastic abundance in field-collected mussels is closely related to human activity, and there is evidence for a positive and quantitative correlation between microplastics in mussels and surrounding waters. Laboratory studies collectively demonstrate that mussels may be good model organisms in revealing microplastic uptake, accumulation and toxicity. Consequently, we propose the use of mussels as target species to monitor microplastics and call for a uniform, efficient and economical approach that is suitable for a future large-scale monitoring program.
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http://dx.doi.org/10.1016/j.envpol.2018.10.032DOI Listing
January 2019

Microplastics in mussels sampled from coastal waters and supermarkets in the United Kingdom.

Environ Pollut 2018 Oct 21;241:35-44. Epub 2018 May 21.

School of Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, United Kingdom. Electronic address:

Global contamination of the marine environment by plastic has led to the discovery of microplastics in a range of marine species, including those for human consumption. In this study, the presence of microplastics and other anthropogenic debris in seawater and mussels (Mytilus edulis) from coastal waters of the U.K., as well as supermarket sources, was investigated. These were detected in all samples from all sites with spatial differences observed. Seawater samples taken from 6 locations (in triplicates) displayed 3.5 ± 2.0 debris items/L on average (range: 1.5-6.7 items/L). In wild mussels sampled from 8 locations around the U.K. coastal environment, the number of total debris items varied from 0.7 to 2.9 items/g of tissue and from 1.1 to 6.4 items/individual. For the supermarket bought mussels, the abundance of microplastics was significantly higher in pre-cooked mussels (1.4 items/g) compared with mussels supplied live (0.9 items/g). Micro-FT-IR spectroscopy was conducted on 136 randomly selected samples, with 94 items characterized. The spectra found that 50% of these debris items characterized were microplastic, with an additional 37% made up of rayon and cotton fibers. The microplastic levels detected in the supermarket bought mussels present a route for human exposure and suggests that their quantification be included as food safety management measures as well as for environmental monitoring health measures.
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http://dx.doi.org/10.1016/j.envpol.2018.05.038DOI Listing
October 2018

Seasonal expression patterns of clock-associated genes in the blue mussel Mytilus edulis.

Chronobiol Int 2017 17;34(9):1300-1314. Epub 2017 Oct 17.

a School of Environmental Sciences , University of Hull , Hull , UK.

Environmental cues allow organisms to synchronise their internal biological rhythms with external environmental cycles. These rhythms are regulated on a molecular level by oscillating interactions between clock genes and their proteins. Light is a particularly relevant environmental cue, provisioning daily information via light/dark cycles as well as seasonal information via day-length (photoperiod). Despite the ecological and commercial importance of bivalves, little is known about the interactions comprising their molecular clock mechanism. This study investigates the link between the annual seasonal progression and reproductive development in the blue mussel (Mytilus edulis), using mRNA expression patterns of clock-associated genes: Clock, Cry1¸ ARNT, Timeout-like, ROR/HR3 and aaNAT, in the gonads of both sexes, sampled over three daily time-points on a tidal beach during the winter and summer solstices. Significant differences in mRNA expression levels, including some seasonal differences at comparable time-points, were detected for all genes with the exception of Timeout-like. These differences occurred seasonally within sex (Clock, Cry1, ROR/HR3), seasonally between sexes (Clock, Cry1, ARNT, ROR/HR3, aaNAT) and daily between sexes (Cry1), although no significant daily differences were detected in summer or winter for either sex for any of the genes. This study reveals that clock-associated genes show seasonal responses in this species of bivalve. Understanding the mechanisms by which environmental cues drive biological rhythms is critical to understanding the seasonal sensitivity of this keystone species to environmental changes.
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http://dx.doi.org/10.1080/07420528.2017.1363224DOI Listing
August 2018

Hepatocellular adenoma in a European flatfish (Limanda limanda): Genetic alterations in laser-capture micro-dissected tissue and global transcriptomic approach.

Mar Pollut Bull 2017 Jun 3;119(2):120-127. Epub 2017 May 3.

School of Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom. Electronic address:

Liver tumours in flatfish have been diagnosed using histopathology for decades to monitor the impacts of marine pollution. Here we describe the application of specific gene (retinoblastoma, Rb) profiling in laser capture micro-dissected samples, and a suppression subtractive hybridization (SSH) approach to isolate differentially expressed genes in hepatocellular adenoma (HCA) samples from dab, Limanda limanda. The Rb profiles from apparently normal and HCA micro-dissected samples of fish from the North Sea showed no significant difference, and genotypic heterogeneity within defined histological phenotypes was observed. In the SSH, sequences associated with cell signalling, cell cycle, gene expression regulation, protein transport and protein degradation were isolated. These included up-regulation of arrestin domain containing 3 (arrdc3), Rac-1 and tribbles, and down-regulation of ankyrin repeat/sterile alpha-motif domain-containing protein 1B-like (ANKS1B-like), c-fos, CDKN1B and RhoA-like sequences, previously implicated in mammalian HCA. This study offers new candidates involved in fish liver tumour development.
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http://dx.doi.org/10.1016/j.marpolbul.2017.04.052DOI Listing
June 2017

Molecular changes in skin pigmented lesions of the coral trout Plectropomus leopardus.

Mar Environ Res 2016 Sep 28;120:130-5. Epub 2016 Jul 28.

School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, United Kingdom. Electronic address:

A high prevalence of skin pigmented lesions of 15% was recently reported in coral trout Plectropomus leopardus, a commercially important marine fish, inhabiting the Great Barrier Reef. Herein, fish were sampled at two offshore sites, characterised by high and low lesion prevalence. A transcriptomic approach using the suppressive subtractive hybridisation (SSH) method was used to analyse the differentially expressed genes between lesion and normal skin samples. Transcriptional changes of 14 genes were observed in lesion samples relative to normal skin samples. These targeted genes encoded for specific proteins which are involved in general cell function but also in different stages disrupted during the tumourigenesis process of other organisms, such as cell cycling, cell proliferation, skeletal organisation and cell migration. The results highlight transcripts that are associated with the lesion occurrence, contributing to a better understanding of the molecular aetiology of this coral trout skin disease.
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http://dx.doi.org/10.1016/j.marenvres.2016.07.009DOI Listing
September 2016

Environmental concentration of carbamazepine accelerates fish embryonic development and disturbs larvae behavior.

Ecotoxicology 2016 Sep 7;25(7):1426-37. Epub 2016 Jul 7.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 200062, Shanghai, China.

Environmental pollution caused by pharmaceuticals has been recognized as a major threat to the aquatic ecosystems. Carbamazepine, as the widely prescribed antiepileptic drug, has been frequently detected in the aquatic environment and has created concerns about its potential impacts in the aquatic organisms. The effects of carbamazepine on zebrafish embryos were studied by examining their phenotype, behavior and molecular responses. The results showed that carbamazepine disturbed the normal growth and development of exposed zebrafish embryos and larvae. Upon exposure to carbamazepine at 1 μg/L, the hatching rate, body length, swim bladder appearance and yolk sac absorption rate were significantly increased. Embryos in treatment groups were more sensitive to touch and light stimulation. At molecular level, exposure to an environmentally relevant concentration (1 μg/L) of carbamazepine disturbed the expression pattern of neural-related genes of zebrafish embryos and larvae. This study suggests that the exposure of fish embryo to antiepileptic drugs, at environmentally relevant concentrations, affects their early development and impairs their behavior. Such impacts may have future repercussions by affecting fish population structure.
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http://dx.doi.org/10.1007/s10646-016-1694-yDOI Listing
September 2016

Exposure to low pH induces molecular level changes in the marine worm, Platynereis dumerilii.

Ecotoxicol Environ Saf 2016 Feb 19;124:105-110. Epub 2015 Oct 19.

School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom. Electronic address:

Fossil fuel emissions and changes in net land use lead to an increase in atmospheric CO2 concentration and a subsequent decrease of ocean pH. Noticeable effects on organisms' calcification rate, shell structure and energy metabolism have been reported in the literature. To date, little is known about the molecular mechanisms altered under low pH exposure, especially in non-calcifying organisms. We used a suppression subtractive hybridisation (SSH) approach to characterise differentially expressed genes isolated from Platynereis dumerilii, a non-calcifying marine polychaeta species, kept at normal and low pH conditions. Several gene sequences have been identified as differentially regulated. These are involved in processes previously considered as indicators of environment change, such as energy metabolism (NADH dehydrogenase, 2-oxoglutarate dehydrogenase, cytochrome c oxidase and ATP synthase subunit F), while others are involved in cytoskeleton function (paramyosin and calponin) and immune defence (fucolectin-1 and paneth cell-specific alpha-defensin) processes. This is the first study of differential gene expression in a non-calcifying, marine polychaete exposed to low pH seawater conditions and suggests that mechanisms of impact may include additional pathways not previously identified as impacted by low pH in other species.
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http://dx.doi.org/10.1016/j.ecoenv.2015.10.008DOI Listing
February 2016

Silver nanoparticles affect the neural development of zebrafish embryos.

J Appl Toxicol 2015 Dec 15;35(12):1481-92. Epub 2015 May 15.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.

Silver nanoparticles (AgNPs) have been widely used in commercial products. This study aims to understand the impact of AgNPs on the early developmental stages in zebrafish (Danio rerio) embryos. Embryos were exposed to two sizes of AgNPs at three dose levels, as well to free Ag(+) ions, for a range of 4-96 h post-fertilization (hpf). The acute exposure study showed that exposure to AgNPs affected the neurological development, and the exposed embryos exhibited anomalies such as small head with hypoplastic hindbrain, small eye and cardiac defects. At the molecular level, AgNPs altered the expression profiles of neural development-related genes (gfap, huC and ngn1), metal-sensitive metallothioneins and ABCC genes in exposed embryos. The expression of AhR2 and Cyp1A, which are usually considered to mediate polycyclic aromatic hydrocarbon toxicity, were also significantly changed. A size-dependent uptake of AgNPs was observed, whereby 4 nm AgNPs were more efficiently taken up compared with the 10 nm-sized particles. Importantly, the head area accumulated AgNPs more efficiently than the trunk area of exposed zebrafish embryos. No free Ag(+) ions, which can be potentially released from the AgNP solutions, were detected. This study suggests that AgNPs could affect the neural development of zebrafish embryos, and the toxicity of AgNPs may be partially attributed to the comparatively higher uptake in the head area. These results indicate the potential neurotoxicity of AgNPs and could be extended to other aquatic organisms.
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http://dx.doi.org/10.1002/jat.3164DOI Listing
December 2015

Effects of low seawater pH on the marine polychaete Platynereis dumerilii.

Mar Pollut Bull 2015 Jun 22;95(1):166-72. Epub 2015 Apr 22.

School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom. Electronic address:

An important priority for any organism is to maintain internal cellular homeostasis including acid-base balance. Yet, the molecular level impacts of changing environmental conditions, such as low pH, remain uncharacterised. Herein, we isolate partial Na(+)/H(+)exchangers (NHE), carbonic anhydrase (CA), and calmodulin (CaM) genes from a polychaete, Platynereis dumerilii and investigate their relative expression in acidified seawater conditions. mRNA expression of NHE was significantly down-regulated after 1h and up-regulated after 7days under low pH treatment (pH 7.8), indicating changes in acid-base transport. Furthermore, the localisation of NHE expression was also altered. A trend of down regulation in CA after 1h was also observed, suggesting a shift in the CO2 and HCO3(-) balance. No change in CaM expression was detected after 7days exposure to acidified seawater. This study provides insight into the molecular level changes taking place following exposure to acidified seawater in a non-calcifying, ubiquitous, organism.
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http://dx.doi.org/10.1016/j.marpolbul.2015.04.027DOI Listing
June 2015

Molecular characterization of an estrogen receptor and estrogen-related receptor and their autoregulatory capabilities in two Mytilus species.

Gene 2015 Jun 8;564(2):153-9. Epub 2015 Apr 8.

Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-amamiyamachi, Sendai 981-8555, Japan. Electronic address:

Vertebrate-like sex steroid hormones have been widely detected in mollusks, and numerous experiments have shown the importance of steroids in gonad development. Nevertheless, their signaling pathways in invertebrates have not been uncovered yet. Steroid receptors are an ancient class of transcription factors with multiple roles in not only vertebrates but also invertebrates. Estrogen signaling is thought to have major roles in mollusk physiology, but the full repertoire of estrogen receptors is unknown. We presented the successful cloning of two novel forms of estrogen receptor-like genes. These receptors are present in two closely related species of Mytilus: Mytilus edulis and Mytilus galloprovincialis, commonly known and widely distributed sentinel species. Our phylogenetic analysis revealed that one of these receptors is an estrogen receptor (ER) and the other one is an estrogen-related receptor (ERR). Studies of expression analysis showed that both receptor mRNAs were localized in the oocytes and follicle cells in contact with developing oocytes in the ovary and Sertoli cells in the testis, and in the ciliated cells of the gill. In addition, we have evidence that one (ER) of these may have a capacity to autoregulate its own expression in the gonadal cells by estrogen (E2) and that this gene is responsive to estrogenic compounds.
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http://dx.doi.org/10.1016/j.gene.2015.03.073DOI Listing
June 2015

Intersex related gene expression profiles in clams Scrobicularia plana: Molecular markers and environmental application.

Mar Pollut Bull 2015 Jun 5;95(2):610-7. Epub 2015 Mar 5.

School of Biological, Biomedical & Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom. Electronic address:

Intersex, the appearance of female characteristics in male gonads, has been identified in several aquatic species. It is a widespread phenomenon in populations of the bivalve, Scrobicularia plana, from the southwest coast of the U.K. Genes previously identified as differentially expressed (ferritin, testicular haploid expressed gene, THEG, proliferating cell nuclear antigen, PCNA; receptor activated protein kinase C, RACK; cytochrome B, CYB; and cytochrome c oxidase 1, COX1) in intersex clams relative to normal male clams, were selected for characterisation and an environmental survey of the Channel region. Transcripts were significantly differentially expressed at sites with varying intersex incidence and contaminant burdens. Significant correlations between specific gene expressions, key contaminants and sampling locations have been identified, though no single gene was associated with intersex incidence. The results highlight the difficulty in understanding the intersex phenomenon in molluscs where there is still a lack of knowledge on the control of normal reproduction.
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http://dx.doi.org/10.1016/j.marpolbul.2015.02.019DOI Listing
June 2015

Use of the enhanced frog embryo teratogenesis assay-Xenopus (FETAX) to determine chemically-induced phenotypic effects.

Sci Total Environ 2015 Mar 5;508:258-65. Epub 2014 Dec 5.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China. Electronic address:

The frog embryo teratogenesis assay-Xenopus (FETAX) is an established method for the evaluation of the developmental toxicities of chemicals. To develop an enhanced FETAX that is appropriate for common environmental contaminants, we exposed Xenopus tropicalis embryos to eight compounds, including tributyltin, triphenyltin, CdCl2, pyraclostrobin, picoxystrobin, coumoxystrobin, all-trans-retinoic acid and 9-cis-retinoic acid. Multiple malformations were induced in embryos particularly following exposure to tributyltin, triphenyltin and pyraclostrobin at environmentally relevant concentrations. Based on the range of observed malformations, we proposed a phenotypic assessment method with 20 phenotypes and a 0-5 scoring system. This derived index exhibited concentration-dependent relationships for all of the chemicals tested. Furthermore, the phenotype profiles were characteristic of the different tested chemicals. Our results indicate that malformation phenotypes can be quantitatively integrated with the primary endpoints in conventional FETAX assessments to allow for increased sensitivity and measurement of quantitative effects and to provide indicative mechanistic information for each tested chemical.
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http://dx.doi.org/10.1016/j.scitotenv.2014.11.086DOI Listing
March 2015

Genetic alterations and cancer formation in a European flatfish at sites of different contaminant burdens.

Environ Sci Technol 2014 Sep 21;48(17):10448-55. Epub 2014 Aug 21.

School of Biological, Biomedical and Environmental Sciences, University of Hull , Cottingham Road, Hull, HU6 7RX, United Kingdom.

Fish diseases are an indicator for marine ecosystem health since they provide a biological end-point of historical exposure to stressors. Liver cancer has been used to monitor the effects of exposure to anthropogenic pollution in flatfish for many years. The prevalence of liver cancer can exceed 20%. Despite the high prevalence and the opportunity of using flatfish to study environmentally induced cancer, the genetic and environmental factors driving tumor prevalence across sites are poorly understood. This study aims to define the link between genetic deterioration, liver disease progression, and anthropogenic contaminant exposures in the flatfish dab (Limanda limanda). We assessed genetic changes in a conserved cancer gene, Retinoblastoma (Rb), in association with histological diagnosis of normal, pretumor, and tumor pathologies in the livers of 165 fish from six sites in the North Sea and English Channel. The highest concentrations of metals (especially cadmium) and organic chemicals correlated with the presence of tumor pathology and with defined genetic profiles of the Rb gene, from these sites. Different Rb genetic profiles were found in liver tissue near each tumor phenotype, giving insight into the mechanistic molecular-level cause of the liver pathologies. Different Rb profiles were also found at sampling sites of differing contaminant burdens. Additionally, profiles indicated that histological "normal" fish from Dogger sampling locations possessed Rb profiles associated with pretumor disease. This study highlights an association between Rb and specific contaminants (especially cadmium) in the molecular etiology of dab liver tumorigenesis.
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http://dx.doi.org/10.1021/es502591pDOI Listing
September 2014

Effects of antagonist of retinoid X receptor (UVI3003) on morphology and gene profile of Xenopus tropicalis embryos.

Environ Toxicol Pharmacol 2014 Jul 27;38(1):153-62. Epub 2014 May 27.

State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; School of Biological, Biomedical and Environmental Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom.

We exposed Xenopus tropicalis embryos to a selective antagonist of retinoid X receptor (UVI3003). UVI3003 induced multiple malformations at the concentrations of 200-1000 μg/L after 48 h exposure. The most prominent malformations affected brains, eyes, cement gland and fins. UVI3003 also induced variable and divergent malformations at 250-1500 μg/L after 0-24 and 24-48 h exposure. Microarray analysis showed that seven genes (rps15, serp2, fmr1, cyp2e1, lrrc9, ugtla6 and LOC100490188) were differentially regulated in all three treatment groups after 0-24h exposure. The most significantly affected pathway was galactose metabolism. In 24-48 h exposure groups, 18 genes were differentially regulated, mainly comprising components of the PPAR signaling pathway. These results suggested that UVI3003 is teratogenic in amphibian embryos. Differential gene expression suggests that galactose metabolism and PPAR signaling pathways may provide underlying mechanistic detail accounting for the observed malformations.
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http://dx.doi.org/10.1016/j.etap.2014.05.010DOI Listing
July 2014

Advanced diagnostics applied to fish liver tumours: relating pathology to underlying molecular aetiology.

Mar Pollut Bull 2013 Jul 16;72(1):94-8. Epub 2013 May 16.

Department of Biological Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom.

Liver tumours in flatfish have been diagnosed using histopathology for decades in order to monitor the impacts of marine pollution in coastal and estuarine environments. This traditional method has been coupled with molecular analyses of tumours in the liver of the dab, Limanda limanda, in order to elucidate underpinning molecular level aetiology of such disease. A laser capture microdissection technique for molecular investigation of cancer has been applied in fish. The present study provides optimized steps for environmental sample utilisation: a procedure for field sample collection and handling; a method allowing reliable identification of lesions on frozen tissue sections; and, downstream molecular analyses of tumourigenesis markers (retinoblastoma gene) in laser microdissected samples. This approach facilitates the use of wild flatfish as a model of environmentally-induced tumourigenesis, and has wide applicability to any disease pathology for which the underpinning molecular aetiology is required.
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http://dx.doi.org/10.1016/j.marpolbul.2013.04.016DOI Listing
July 2013

Intersex in Scrobicularia plana: transcriptomic analysis reveals novel genes involved in endocrine disruption.

Environ Sci Technol 2012 Dec 14;46(23):12936-42. Epub 2012 Nov 14.

Department of Biology and Environmental Science, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QJ, United Kingdom.

Intersex, the appearance of female characteristics in male gonads, has been identified in a wide range of aquatic species worldwide, yet the underpinning molecular etiology remains uncharacterized. The presence of intersex has been shown to be a widespread phenomenon in bivalve, S. plana, populations from the southwest coast of the U.K., as well as inducible in an experimental exposure regime using endocrine disrupting compounds (EDCs). Herein, we use the suppressive subtractive hybridization approach to isolate differentially expressed transcripts in S. plana males exhibiting intersex. Transcripts involved in cell signaling, cell cycle control, energy production/metabolism, microtubule assembly, and sperm physiology are all highlighted as differentially expressed in intersex male clams. These provide both an insight into the molecular mechanisms of action involved in the development of intersex, as well as facilitating potential molecular-level "early warning" biomarkers of the condition.
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http://dx.doi.org/10.1021/es302948gDOI Listing
December 2012

Ionizing radiation-induced DNA damage response identified in marine mussels, Mytilus sp.

Environ Pollut 2012 Sep 17;168:107-12. Epub 2012 May 17.

School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK.

There is growing concern over the potential detrimental impact of ionizing radiation on natural biota. The mechanistic cause-and-effect impact of ionizing radiation has yet to be characterized in any aquatic species. Adopting an integrated approach, including radiochemical analysis of environmental samples, we evaluate molecular responses to ionizing radiation in the marine mussel, Mytilus edulis. These responses included analyses of RAD51 mRNA expression, a gene involved in the repair of DNA double strand breaks, and induction of DNA strand breaks using the comet assay, in samples collected from a site impacted by low level ionizing radiation discharges. Based on activities of the radionuclides measured in sediment and mussel tissue at the discharge site, external and internal dose rates were low, at ca. 0.61 μGyh(-1) and significantly lower than the generic (all species) "no effect" dose rate of 10 uGyh(-1), yet DNA strand breakage and RAD51 mRNA expression were both altered.
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http://dx.doi.org/10.1016/j.envpol.2012.04.015DOI Listing
September 2012
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