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1.
Article in English | MEDLINE | ID: mdl-33797503

ABSTRACT

BACKGROUND: The Caribbean is a unique region of islands and cays home to nearly 43 million people. A significant challenge facing this population is the burden of traumatic brain injury, which disproportionately affects younger individuals and carries a significant economic burden. A preventive measure to reduce this burden is consistent wearing of helmets. This study aims to assess TBI prevention through helmet safety in Caribbean nations in order to demonstrate the regional impact of public health solutions. METHODS: We assess the member states of the Caribbean Community (CARICOM) and sought to evaluate CARICOM nations' TBI prevention through helmet safety with relation to public health, policy, laws, infrastructure, and regulations. We produced the Rolle Scoring System (RSS) to ascertain the influence of governance around helmet safety for TBI prevention. The RSS aims to provide a quantifiable method of how well a CARICOM nation is performing in efforts to reduce TBI. The RSS is broken down into 2 categories, with scores ranging from 1 (worst) to 5 (best). The range of possible scores a CARICOM nation could receive was 8 to 40. RESULTS: Fourteen CARICOM nations were ultimately incorporated into our analysis. From the initial cohort, 3 were removed. These nations were Anguilla, Saint Kitts & Nevis, and Montserrat. We analyzed values derived from the RSS, finding a mean Rolle score of 22. We further subdivided the nations into low Rolle score (8-24) and high Rolle score (>24). Trinidad and Tobago had the highest Rolle score at 29. Haiti was found to have the lowest Rolle score at 8. CONCLUSION: Several Caribbean nations have demonstrated leadership pertaining to TBI prevention through helmet safety. The regional momentum of helmet safety in the Caribbean can serve as a model for other geographical regional blocs that share interests and culture to consider comprehensive approaches to public health challenges.

2.
Animals (Basel) ; 11(4)2021 Mar 30.
Article in English | MEDLINE | ID: mdl-33808163

ABSTRACT

Capture-based aquaculture (CBA) represents a type of intensive aquaculture production system for some economically valuable fish species, such as bluefin tuna (Thunnus thynnus), eel (Anguilla spp.) and Atlantic cod (Gadus morhua). In CBA, fish are captured from the wild in certain periods of the year, and following a recovery phase, they are kept in rearing facilities for a period of time, until they reach the market size. In this case, the fish are wild and have not gone through domestication like other fish species that are reproduced and farmed under the established farming systems. Therefore, these fish are not genetically adapted to live under the intensive farming conditions, and thus their welfare may be compromised in different manners compared to their domesticated counterparts. This review presents an overview of the current situation of CBA, while focusing on the assessment of fish welfare in CBA. The most commonly used fish welfare indicators will be discussed in relation to the different stages of CBA.

3.
Dev Comp Immunol ; : 104044, 2021 Apr 26.
Article in English | MEDLINE | ID: mdl-33915176

ABSTRACT

As a member of inhibitory κB family (IκB) family, IκBα is best-characterized and plays a central negative feedback regulator of NF-κB pathway in mammals, but the information about IκBα in the regulation of immune responses is still limited in teleost fishes. In the present study, the full-length cDNA of an IκBα homologue, AjIκBα, was cloned by 5' and 3' SMART RACE from Japanese eel, and its characteristics of expression in response to various PAMPs and A. hydrophila infection were investigated both in vivo and in vitro using quantitative real-time polymerase chain reaction (qRT-PCR). In addition, the subcellular localization of AjIκBα GFP fusion protein and the induction of AjIκBα alone or co-expression with Japanese eel IKKα (AjIKKα) in the activation of NF-κB, type I IFN and AP1 performed using Dual-Glo luciferase assay system were also detected. Sequence comparison analysis revealed that AjIκBα has typical conserved domains, including the N-terminal conserved degradation motif, the ankyrin repeats, and the C-terminal PEST domain. The predicted three-dimensional structure of AjIκBα is similar to that of human IκBα. qRT-PCR analysis revealed a broad expression for AjIκBα in a wide range of tissues, with the highest expression in the spleen, followed by intestine, liver, gills, skin, kidney, and with a lower expression in the heart and muscle. The AjIκBα expressions in the kidney, spleen, and especially in liver were significantly induced following injection with Gram-negative bacterial component LPS, the viral mimic poly I:C and Aeromonas hydrophila infection. In vitro, the AjIκBα transcripts of Japanese eel liver cells were significantly enhanced by the treatment of LPS, poly I:C, or the stimulation of different concentration of Aeromonas hydrophil. Luciferase assays demonstrated that not only could the AjIκBα expression significantly decrease the activation of NF-κB, AP1, and IFNß-responsive promoters in HEK293 cells and EPC cells, but also robustly inhibited the activity of these three promoters in HEK293 cells or NF-κB and AP1-responsive promoters in EPC cells induced by AjIKKα. Additionally, subcellular localization studies showed that AjIκBα was evenly distributed in the cytoplasm and nucleus both in HEK293 cells and EPC cells under natural state. AjIκBα was found to aggregate into spots in the cytoplasm and nucleus stimulated by LPS or mostly aggregate into nucleus with the treatment of poly I:C in HEK293 cells, whereas the elevated expression of AjIκBα was observed in the cytoplasm of EPC cells upon the stimulation of poly I:C. These results collectively indicated that AjIκBα function as an important negative regulation in innate immunity of host against antibacterial and antiviral infection likely via the inhibition of the activation of NF-κB, AP1, and type I IFN signaling pathways.

4.
Sci Total Environ ; 784: 147042, 2021 Apr 20.
Article in English | MEDLINE | ID: mdl-33895513

ABSTRACT

The fitness of restocked European eel (Anguilla anguilla), an endangered fish species, was studied in relation to the environmental variables of habitats in six upland rivers that are typologically different in terms of their hydromorphological and physicochemical characteristics, food resources and fish communities. These rivers received a total of 76,370 imported glass eels in 2017. During a three-year period, we monitored eels with respect to total length, annual growth rate, condition factor and density using capture-mark-recapture experiments to understand the effects of the characteristics of receiving rivers on restocking success levels. Our results showed the survival of the restocked eels in the six rivers and revealed significant differences between them in terms of total length, condition factor and density. Better performance in eel yield variables was observed in a eutrophic alkaline river with greater roughness of riverbed substrates, dominant pool- and riffle-type flow facies and lower brown trout density. The variables conductivity and total hardness had higher explanatory power and were strongly associated with increased eel density. This study suggests that a well-selected habitat/river in a restocking programme can be beneficial for the species and recommends restocking practice as a management tool to achieve eel conservation goals.

5.
Syst Parasitol ; 98(3): 255-275, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33840001

ABSTRACT

Tapeworms (Cestoda) of the Proteocephalus-species aggregate from cyprinoids, pike, eel, smelt and cavefish in the Nearctic region (North America) are reviewed, based on a critical examination of newly collected and museum specimens. For some species neither new nor museum specimens were available and only literature data were used for these taxa. Two species occur in North American cyprinoids: (i) Nearctic Proteocephalus buplanensis Mayes, 1976 in Semotilus atromaculatus (Mitchill) in the upper Mississippi River and Hudson Bay drainage basins, and (ii) Holarctic P. torulosus (Batsch, 1786) (syns. P. ptychocheilus Faust, 1919; P. cobraeformis Haderlie, 1953; and Ophiotaenia critica Mpoame & Landers, 1981, new synonym), which occurs in Ptychocheilus spp. and other leuciscids in the western part of North America. Proteocephalus pinguis La Rue, 1911 is a specific parasite of pike (Esox spp.), which is briefly redescribed here to establish its diagnostic morphological characteristics because the original description was based on a mixture of at least two species. In addition to P. pinguis, pike serve as postyclic hosts of several species of the Proteocephalus-aggregate typical of other fish, such as bass, perch and whitefish, namely P. fluviatilis Bangham, 1925, P. pearsei La Rue, 1919 and P. longicollis (Zeder, 1800). Cavefish (Amblyopsidae) in North America harbour two endemic species, P. chologasteri Whittaker & Hill, 1968 from Chologaster agassizii Putman and P. poulsoni Whittaker & Zober, 1978 from Amblyopsis spelaea DeKay, which have never been found since their original description and their validity should be confirmed based on new collections and molecular data. Two other species of the Proteocephalus-aggregate, P. macrocephalus (Creplin, 1825), a parasite of eels (Anguilla spp.), and P. tetrastomus (Rudolphi, 1810) from smelt (Osmeridae), have circumboreal (Holarctic) distribution. Molecular data are available only for three of the seven species treated herein, but they do not form a monophyletic group.

6.
J Fish Biol ; 2021 Mar 02.
Article in English | MEDLINE | ID: mdl-33651431

ABSTRACT

Water-choice trial experiments revealed that Anguilla japonica glass eels collected in southern Japan possess strong preferences for fresh water and agricultural water. Their locomotor activity and preference for fresh water were higher and stronger, respectively, in this study when compared to previous studies conducted at lower temperatures. These results suggest that their locomotor activity and preference for fresh water is influenced by water temperature. The attraction to agricultural water indicates their upstream migration and habitat selection could be influenced by agricultural water.

7.
J Morphol ; 2021 Mar 28.
Article in English | MEDLINE | ID: mdl-33774837

ABSTRACT

The lateral line system and its innervation were examined in the Japanese eel Anguilla japonica. Although the species has seven lateral line canals and 13 superficial neuromast groups, the components are generally similar to those in many other teleosts. The lateral line system of A. japonica is distinctive in having a rostral commissure connecting the left and right supraorbital canals, pouches in the cephalic lateral line canals and superficial neuromasts along the lower lip, and lacking a postotic canal. Four tube-like elements, two along the supratemporal canal and the other two along the temporal portion of the trunk canal, respectively, are also reported. The functional significance of cephalic lateral line pouches, homologies of the four tube-like elements, and other distinctive characters are discussed.

8.
Article in English | MEDLINE | ID: mdl-33684553

ABSTRACT

The olfactory epithelium of the sea catfish, Ariopsis felis, is found on a pinnate array of lamellae (the olfactory rosette) housed within a nasal chamber. The nasal anatomy of A. felis suggests an ability to capture external water currents. We prepared models from X-ray micro-computed tomography scans of two preserved specimens of A. felis. We then used dye visualisation and computational fluid dynamics to show that an external current induced a flow of water through a) the nasal chamber and b) the sensory channels of the olfactory rosette. The factors responsible for inducing flow through the nasal chamber are common to fishes from two other orders. The dye visualisation experiments, together with observations of sea catfishes in vivo, indicate that flow through the nasal chamber is regulated by a mobile nasal flap. The position of the nasal flap - elevated (significant flow) or depressed (reduced flow) - is controlled by the sea catfish's movements. Flow in the sensory channels of the olfactory rosette can pass through either a single channel or, via multiple pathways, up to four consecutive channels. Flow through consecutive sensory channels (olfactory resampling) is more extensive at lower Reynolds numbers (200 and 300, equivalent to swimming speeds of 0.5-1.0 total lengths s-1), coinciding with the mean swimming speed of the sea catfishes observed in vivo (0.6 total lengths s-1). Olfactory resampling may also occur, via a vortex, within single sensory channels. In conclusion, olfactory flow in the sea catfish is regulated and thoroughly sampled by novel mechanisms.

9.
J Fish Dis ; 2021 Mar 25.
Article in English | MEDLINE | ID: mdl-33764551

ABSTRACT

Giant mottled eel (Anguilla marmorata) farming in Vietnam is a multistage process starting from wild harvest of glass eels through the so-called "hatcheries" and distribution centres from which individuals are transferred to rearing farms and subsequently sold by one eel farm to another every 3-5 months. The information on viral agents spread and persistence in the Vietnamese eel aquaculture is scarce. Therefore, the mortality of A. marmorata at the Van Xuan Farm was the prerequisite to identify the possible aetiologic agent and additionally to formulate first recommendations for viral disease screening in the Vietnamese eel aquaculture. Juvenile giant mottled eels with haemorrhagic lesions in the skin and liver, and hyperaemia of the gut were tested with qPCR and end-point PCR for AngHV-1 presence. Here, we report the first detection of AngHV-1 associated with mortality in giant mottled eel in winter and spring seasons. On the basis of the obtained results, we recommend to test eel seeds in "hatcheries," since tropical eel farms operate in interconnected scheme and monitoring of AngHV-1 prevalence requires well-implemented measures. Disease screening in the rearing centres and on-growing facilities should be based on everyday health checks, including by-catch fish used as a base of the feeding programmes at eel farms in Vietnam.

10.
Parasitol Res ; 120(5): 1897-1902, 2021 May.
Article in English | MEDLINE | ID: mdl-33674925

ABSTRACT

The European eel Anguilla anguilla is listed as critically endangered by the IUCN. Among many threats, the introduced parasitic nematode Anguillicola crassus is suspected to alter the eels' swim bladder and jeopardize their reproductive oceanic migration. To date, gaining knowledge about the distribution and prevalence of A. crassus requires individual sacrifice (over 50,000 eels were sacrificed for epidemiology studies since 2010). This paper describes a non-lethal molecular protocol for identifying prevalence of A. crassus in A. anguilla, based on searching for A. crassus DNA in the feces of eels. Tests using three DNA microsatellite markers specific to the nematode showed that molecular detection provided similar results to visual examination of the swim bladder in up to 80% of the cases, and allowed for comparison of prevalence among sites. Easy to implement, this non-lethal protocol for detecting A. crassus could be valuable for management plans of this endangered species.

11.
Microb Pathog ; 153: 104801, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33610715

ABSTRACT

Edwardsiella anguillarum is one of the common bacterial pathogens for the cultivated eels in China. The aim of this study was to reveal the cause of E. anguillarum pathogenic to European eel (Anguilla anguilla) from the perspective of the transcriptome. In this study, we first prepared E. anguillarum cultured in vitro and analysed the whole transcriptome after extracting the total RNA. Then, eels were i.p injected with E. anguillarum, and total RNA were extracted from the liver of European eels 48 h after the infection. After sequencing the transcriptome, we obtained average 1.97 × 108 clean reads cultured in vitro and 1.36 × 105 clean reads located in vivo after annotating all reads into the genome of E. anguillarum. The whole transcriptome showed, compared to the E. anguillarum cultured in vitro, 503 significantly up and 657 significantly down-regulated different expressed genes (DEGs) were observed. KEGG analysis showed that 38 DEGs of Two-Component System, 41 DEGs of ABC transporter, and 10 DEGs flagellar assembly pathways were highly upregulated in E. anguillarum located in vivo. Then, we designed primers to analyse the up-regulated DEGs through qRT-PCR and confirmed some up-regulated DEGs. The results of this study provide important reference for the further study of pathogen-host interaction between E. anguillarum and European eel.

12.
Sci Total Environ ; 774: 145499, 2021 Jun 20.
Article in English | MEDLINE | ID: mdl-33610990

ABSTRACT

The European eel (Anguilla anguilla) has attracted scientific inquiry for centuries due to its singular biological traits. Within the European Union, glass eel fisheries have declined sharply since 1980, from up to 2000 t (t) to 62.2 t in 2018, placing wild populations under higher risk of extinction. Among the major causes of glass eels collapse, climate change has become a growing worldwide issue, specifically ocean warming and acidification, but, to our knowledge, data on physiological and biochemical responses of glass eels to these stressors is limited. Within this context, we selected some representative biomarkers [e.g. glutathione peroxidase (GPx), catalase (CAT), total antioxidant capacity (TAC), heat shock proteins (HSP70), ubiquitin (Ub) and DNA damage] to study physiological responses of the European glass eel under distinct laboratory-climate change scenarios, such as increased water temperature (+ 4 °C) and pH reduction (- 0.4 units), for 12 weeks. Overall, the antioxidant enzymatic machinery was impaired, both in the muscle and viscera, manifested by significant changes in CAT, GPx and TAC. Heat shock response varied differently between tissues, increasing with temperature in the muscle, but not in the viscera, and decreasing in both tissues under acidification. The inability of HSP to maintain functional protein conformation was responsible for boosting the production of Ub, particularly under warming and acidification, as sole stressors. The overproduction of reactive oxygen species (ROS), either elicited by warming - due to increased metabolic demand - or acidification - through H+ interaction with O2-, generating H2O2 - overwhelmed defense mechanisms, causing oxidative stress and consequently leading to protein and DNA damage. Our results emphasize the vulnerability of eels' early life stages to climate change, with potential cascading consequences to adult stocks.


Subject(s)
Anguilla , Animals , Antioxidants , DNA Damage , Hydrogen Peroxide , Hydrogen-Ion Concentration , Oceans and Seas
13.
Article in English | MEDLINE | ID: mdl-33610026

ABSTRACT

Environmental salinity not only affects the physiological processes such as osmoregulation and hormonal control, but also changes the immune system in fishes. Studies are limited in fish on the roles of the T cell receptor (TCR)-related genes in relation to changes in environmental salinity. A large group of salinity-challenged transcripts was obtained in gills of marbled eel (Anguilla marmorata). Moreover, bioinformatic ways were used to identify the enriched TCR pathway related genes which were significantly different expressed in fresh water (FW), brackish water (BW) and seawater (SW). Meanwhile, the RT-qPCR results were validated and consistent with the RNA-seq results. TCR a, TCR b, CD45, CD28, PI3K, LCK and LAT were up-regulated when the salinity increases in BW and SW, which connected with the related signaling pathways (Ras-MAPK and PKC pathway). CD4 and Zap70 were down-regulated when the salinity increases in BW and SW, which connected with the PLC pathway. The research offers a novel viewpoint to explore the immune pathways including the TCR pathway in fish based on transcriptome.

14.
Parasitol Res ; 120(4): 1247-1268, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33544226

ABSTRACT

The global invasive anguillid gill parasite Pseudodactylogyrus anguillae (Yin and Sproston, 1948) has only recently been documented from eels in South Africa. As there is no known eel trade in South Africa, the source of introduction of this parasite has been debated, and its status as an alien parasite was rendered uncertain. We report on the first infection of Pseudodactylogyrus anguillae from the giant mottled eel Anguilla marmorata from the Phongolo River (South Africa) using classic morphological and molecular methodologies and clarify the introduction status category of this parasite as alien and invasive.

15.
Parasitology ; 148(5): 612-622, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33557973

ABSTRACT

The swimbladder functions as a hydrostatic organ in most bony fishes, including the European eel, Anguilla anguilla. Infection by the nematode Anguillicoloides crassus impairs swimbladder function, significantly compromising the success of the eel spawning migration. Swimbladders from 32 yellow eels taken from Lake Trasimeno (Central Italy) were analysed by histopathology- and electron microscopy-based techniques. Sixteen eels (50%) harboured A. crassus in their swimbladders and intensity of infection ranged from 2 to 17 adult nematodes per organ (6.9 ± 1.6, mean ± s.e.). Gross observations of heavily infected swimbladders showed opacity and histological analysis found a papillose aspect to the mucosa and hyperplasia of the lamina propria, muscularis mucosae and submucosa. Inflammation, haemorrhages, dilation of blood vessels and epithelial erosion were common in infected swimbladders. In the epithelium of parasitized swimbladders, many empty spaces and lack of apical junctional complexes were frequent among the gas gland cells. In heavily infected swimbladders, we observed hyperplasia, cellular swelling and abundant vacuolization in the apical portion of the gas gland cells. Numerous mast cells and several macrophage aggregates were noticed in the mucosal layer of infected swimbladders. We found more nervous and endocrine elements immunoreactive to a panel of six rabbit polyclonal antibodies in infected swimbladders compared to uninfected.

16.
Environ Pollut ; 274: 116585, 2021 Apr 01.
Article in English | MEDLINE | ID: mdl-33556797

ABSTRACT

Artificial light at night (ALAN) is considered one of the most pervasive forms of environmental pollution. It is an emerging threat to freshwater biodiversity and can influence ecologically important behaviours of fish. The European eel (Anguilla anguilla) is a critically endangered catadromous species that migrates downstream to the ocean to spawn in the Sargasso Sea. Given the pervasive nature of ALAN, many eel will navigate through artificially lit routes during their seaward migration, and although considered negatively phototactic, their response has yet to be quantified. We investigated the response of downstream moving European eel to simulated ALAN using a Light Emitting Diode unit in an experimental flume. We presented two routes of passage under: (1) a dark control (both channels unlit), (2) low ALAN (treatment channel lit to ca. 5 lx), or (3) high ALAN (treatment channel lit to ca. 20 lx). Eel were: (i) more likely to reject an illuminated route when exposed to high levels of ALAN; (ii) less likely to select the illuminated channel when given a choice; and (iii) passed downstream more rapidly when the illuminated route was selected. This study quantified the response of the critically endangered European eel to ALAN under an experimental setting, providing the foundations for future field based research to validate these findings, and offering insight on the ecological impacts of this major environmental pollutant and driver of global change.


Subject(s)
Anguilla , Animal Migration , Animals , Environmental Pollution , Fresh Water , Seafood
17.
Ecol Appl ; : e2301, 2021 Feb 09.
Article in English | MEDLINE | ID: mdl-33560524

ABSTRACT

Loss of knowledge about historical environmental conditions and species' abundances threatens how new generations potentially perceive their environment and take action. The inter-generational shift in perceptions of environmental thresholds is a phenomenon frequently termed, shifting baseline syndrome (SBS). The goals of this study were (i) to determine relationships between ordinal scores (e.g. few, many) and quantitative measures (e.g. estimates of population size) used by members of a Maori community in New Zealand to score indicators for understanding the abundance of forest resources; and (ii) to then analyse these relationships according to people's age to detect the effects of SBS and the rate that this shift was occurring for each indicator. We detected consistent relationships between the ordinal scores and quantitative measures for six forest indicators provided by community members. However, there was only a high degree of confidence about the direction of the age effect for three abundance indicators [kereru, NZ pigeon, Hemiphaga novaeseelandiae, 15% increase (CI = 5.1 - 27.1%) in flock size for any given ordinal category for each decade increase in age; long-finned eel, Anguilla dieffenbachia, 30% decrease (CI = -45.1 - -11.3%) in the distance (m) walked along a riverbank between observations of an eel for any given ordinal category for each decade increase in age; and Australian brush-tailed possum, Trichosurus vulpecula, 27% decrease (CI = -38.9 - -13.9%) in the distance (m) walked through forest between observations of possum sign for any given ordinal category for each decade increase in age), but the effect was statistically strong for all three. The decoupling of indigenous peoples and local communities (IPLC) from their traditional lands and biodiversity by an array of political, environmental, social and economic drivers and feedback mechanisms have contributed to and exacerbated the conditions for SBS. However, the protection of customary practices to engage with the environment, including the harvest of natural resources, community-based environmental monitoring initiatives, and cultural immersion education programmes offer opportunities for IPLC to mitigate the often deleterious effects of SBS.

18.
Zoology (Jena) ; 145: 125888, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33508724

ABSTRACT

The baggy skins of hagfishes confer whole-body flexibility that enables these animals to tie themselves into knots without injury. The skin's looseness is produced by a subcutaneous blood sinus that decouples the skin and body core and permits the core to contort dramatically without loading the skin in tension or shear. Hagfish skin represents a biological composite material comparable in strength and stiffness to the conventionally taut skins of other fishes. However, our understanding of hagfish skin is restricted to only one of 78 species: The Pacific hagfish Eptatretus stoutii. To determine if other hagfish share similar characteristics with E. stoutii, we measured material properties and compared histological data sets from the skins of four hagfish species: E. springeri, E. stoutii, Myxine glutinosa, and M. hubbsi. We also compared these material properties data with skins from the American eel, Anguilla rostrata. We subjected skin samples from all species to uniaxial tensile tests in order to measure strength, stiffness, extensibility, and toughness of skins stretched along longitudinal and circumferential axes. We also used a series of equibiaxial tensile tests on skin samples from E. stoutii, M. glutinosa, and A. rostrata to measure stiffness of skins simultaneously strained along both axes. Significant results of uniaxial and biaxial tests show that the skins from Eptatretus are anisotropic, being stiffer in the longitudinal axis, and more extensible than the isotropic skins of Myxine. Skins of A. rostrata were stiffer in the circumferential axis and they were stronger, tougher, and stiffer than all hagfish skins examined. The skins of Eptatretus are histologically distinct from Myxine skins and possess arrays of fibers that stain like muscle. These interspecific differences across hagfish skins show a phylogenetic pattern with knotting kinematics and flexibility; both genera belong to distinct but major subfamilies within the Myxinidae, and Eptatretus is known for creating and manipulating a greater diversity of knotting styles than Myxine.

19.
Chemosphere ; 263: 128315, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33297250

ABSTRACT

The traditional approach to extracting estrogens from water matrices, solid-phase extraction (SPE), presents a number of challenges when applied to complex wastewater matrices. Conversely, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) clean-up method offers an alternative sample preparation approach that omits sample filtration and overcomes additional challenges associated with SPE. The objective of this study was to implement and validate a scaled QuEChERS method, using a standard addition approach, for extracting estrone (E1), 17ß-estradiol (E2), and estriol (E3) from the estrogenic influent of a recirculating aquaculture system containing American eels (Anguilla rostrata). While traditional QuEChERS protocols do not facilitate considerable sample concentration, a 500-fold concentration factor was implemented for reliable quantitation of parts-per-trillion concentrations of estrogens from an initial sample volume of 20 mL to a final extract volume of 40 µL. Following analysis via high-performance liquid chromatography-mass spectrometry, excellent process efficiencies were observed at spiked concentrations of 10 and 50 ng L-1 for E2 and E1 (101 to 111%; %RSD ≤ 16), and moderate to acceptable process efficiencies were achieved for E3 (75 to 87%; %RSD ≤ 16). Validation of method parameters, including specificity, linearity, accuracy (recovery and process efficiencies), precision (intra-day precision, and inter-day precision), matrix effects, method detection limit, and limit of quantitation, led to reliable quantitation of unknown concentrations of E1, E2, and E3 in the aquaculture influent as low as 52, 20, and 33 ng L-1, respectively. This study provides a validated analytical method for waste systems requiring quantitation of estrogens in their complex wastewater matrices.


Subject(s)
Estrogens , Water , Chromatography, High Pressure Liquid , Chromatography, Liquid , Estrogens/analysis , Limit of Detection , Solid Phase Extraction , Tandem Mass Spectrometry
20.
Article in English | MEDLINE | ID: mdl-33002594

ABSTRACT

In the eel ovary, the expression of growth differentiation factor-9 (Gdf9) appears to be largely confined to the germ cell in early stages of oogenesis. However, both the target tissue and the function of Gdf9 in fish remain unknown. This study aimed to describe the abundance and localization of activin receptor-like kinase-5 (Alk5) and bone morphogenetic protein receptor type II (Bmpr2), which together mediate the Gdf9 signal, in the ovary of a basal teleost, the shortfinned eel, Anguilla australis, during early folliculogenesis. The cDNA encoding eel alk5 and bmpr2 genes were cloned, characterized and the transcript abundances of these receptors quantified by quantitative real-time PCR. Ovarian transcript abundance for both receptors, along with that of gdf9 and of its paralogue bmp15, increased from the previtellogenic to early vitellogenic stage. Localization of receptor mRNAs by in situ hybridization revealed that these receptors are located in the somatic cells surrounding the oocyte. Furthermore, tissue distribution analysis showed that the expression of alk5 and bmpr2 were highest in ovary and thyroid, respectively. Unexpectedly, however, bmpr2 mRNA levels were lower in the ovary than in any of the other 17 tissues examined, and indeed, lower than ovarian gdf9 transcript abundance. These findings, together with the ovarian expression pattern of Gdf9, suggest that Gdf9, and conceivably, Bmp15, from the oocyte can signal through receptors that are located on the somatic cells surrounding the oocyte; this, in turn, facilitates elucidation of the function of these growth factors during oogenesis in teleost fish.

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