Intersexuality in crustaceans: Genetic, individual and population level effects

Ford, Alex T.; Sambles, Christine; Kille, Peter

doi:10.1016/j.marenvres.2008.02.067

Cited by 9 publications

(9 citation statements)

References 9 publications

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“…This study has used both high-throughput sequencing and qPCR assays to determine that the level of Vtg expression in E. marinus males presenting distinct intersex phenotypes is very low and indistinguishable from that observed in normal males. The extent of feminisation or 'de-masculinisation' presented by both the male intersex phenotypes has made E. marinus a potential model for the study of sexual dysfunction in crustaceans, from the molecular to the population level (eg Ford et al, 2008;Short et al, 2012a;Ford et al, 2007). Furthermore, the very low level of Vtg expression in normal male amphipods (Xuerub et al, 2011), combined with findings showing that this expression remains effectively unchanged throughout all stages of spermatogenesis (Jubeaux et al, 2012c), makes an amphipod species presenting male intersex phenotypes ideal for testing the suitability of Vtg genes as biomarkers of feminisation.…”

Section: Expression Of the Vtg Gene In Feminised Malesmentioning

confidence: 99%

Vitellogenin is not an appropriate biomarker of feminisation in a Crustacean

Short¹,

Yang²,

Kille³

et al. 2014

Aquatic Toxicology

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The expression of the yolk protein vitellogenin (Vtg) has been used as a biomarker of feminisation in multiple fish species throughout the world. Since the late 1990s, researchers have attempted to develop similar biomarkers to address whether reproductive endocrine disruption also occurs in the males of invertebrate groups such as the Crustacea. To date, the vast majority of studies investigating Vtg induction in male Crustacea have resulted in negative or inconclusive results, leading researchers to question the utility of Vtg expression as a biomarker in this taxon. This study measured the expression of Vtg genes in two intersex phenotypes (termed internal and external) found in the male amphipod, Echinogammarus marinus, and compared them with those of normal males and females. Males presenting the external intersex phenotype are infected with known feminising parasites and display a variety of feminised traits including oviduct structures on their testes and external female brood plates (oostegites). The internal intersex male phenotype, that displays a pronounced oviduct structure on the testes without the external intersex characteristics, is not parasite infected and it is thought to be a result of environmental contamination. Given their morphology, these phenotypes might be considered highly 'feminised' or 'de-masculinised' and can be utilised to test the suitability of feminisation biomarkers. The E. marinus transcriptome was searched for genes resembling Vtg and two sequences were revealed, that we subsequently refer to as Vtg1 and Vtg2. Results from a high-throughput transcriptomic sequencing screen of gonadal cDNA libraries suggested that very low expression (in this manuscript gene transcription is taken to represent gene expression, although it is acknowledged that in addition to transcription, translation, transcript processing, mRNA stability and protein stability can regulate gene expression) of Vtg1 and Vtg2 in normal males (ESTs=1 and 0 for Vtg1 and Vtg2, respectively), internal intersex males (ESTs=0 for both Vtg sequences) and external intersex males (ESTs=5 and 0 for Vtg1 and Vtg2, respectively). In contrast, the sequencing suggested notable levels of expression of both Vtg genes in females (ESTs=1133 and 84 for Vtg1 and Vtg2, respectively). Subsequent qPCR analysis validates these expression levels, with the signal for Vtg1 and Vtg2 transcripts in all male phenotypes being indistinguishable from that caused by contamination of trace levels of genomic DNA or the low-level amplification non-target sequences. These findings suggest that Vtg expression is not notably induced in highly feminised amphipods and is therefore not an appropriate biomarker of feminisation/de-masculination in crustaceans. We discuss our findings in the context of previous attempts to measure Vtg in male crustaceans and suggest a requirement for more appropriate taxon-specific biomarkers to monitor feminisation in these groups.

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Section: Expression Of the Vtg Gene In Feminised Malesmentioning

confidence: 99%

Vitellogenin is not an appropriate biomarker of feminisation in a Crustacean

Short¹,

Yang²,

Kille³

et al. 2014

Aquatic Toxicology

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“…Identification of specific gene functions of amphipods for development of gene transcript biomarkers of chemical exposure is presently at an early stage of development, and the only aquatic invertebrate whose genome has been sequenced is D. pulex (http://wfleabase.org/). A limited number of expressed sequence tag studies for a few other crustaceans have yielded some cDNA libraries for the amphipod Gammarus pulex, representing a range of developmental stages and phases of the molt cycle for both sexes together with sex-specific subtractive suppression hybridization libraries [131]. A microarray has recently been constructed from expressed sequence tags from Hyalella azteca [https://wiki.cgb.indiana.edu/display/grp/Hyalellaþazteca] for the evaluation of gene expression signatures after exposure to different sediment pollutants and to correlate changes with whole animal toxicity.…”

Section: Biomarkers For Reproductive Toxicity From Contaminant Exposurementioning

confidence: 99%

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Hyne¹

2011

Enviro Toxic and Chemistry

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Abstract-The reproductive biology of amphipods is reviewed to update the knowledge of the male and female reproductive processes of oogenesis and spermatogenesis as well as the endocrine systems of amphipods with the aim of advancing studies of reproductive toxicology. The ovarian and reproduction cycles of female gammaridean amphipods are closely correlated with the molt cycle, which is under direct control by the steroid hormone 20-hydroxyecdysone. The ability of males to copulate and subsequently for females to ovulate is restricted to the early postmolt period of the females. New developments in our understanding of the molt cycle and the endocrine regulatory pathways for reproduction using genomics techniques on other crustacean species are also discussed. The arthropod sterol ponasterone A or xenobiotics such as the fungicide fenarimol have been shown to elicit endocrine disruption in some crustaceans by acting as an agonist for 20-hydroxyecdysone at the ecdysone receptor or by inhibiting the synthesis of 20-hydroxyecdysone, respectively, resulting in disruption of molting and reproduction. Recent studies suggest that cadmium can inhibit secondary vitellogenesis in amphipods. Experimental approaches for examining the metabolic pathways associated with ecdysteroid hormonal signaling or metabolism, exoskeleton maintenance and molting, and the regulation of vitellogenin in amphipods are discussed. This information should aid in the identification of useful biomarkers for reproductive toxicity. Environ. Toxicol. Chem.

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“…By 1999, compounds such as the common herbicides atrazine, simazine and Diuron, metals and organometallic compounds such as mercury, cadmium, or organotins, insecticides such as Toxaphene, DDT, or Endrin, alkylphenols such as nonylphenol or PCBs such as Aroclor 1242 or natural or synthetic vertebrate steroids such as diethylstilbestrol or testosterone were implicated in causing endocrine disruption in invertebrates (8). Evidence mounted ever since, and this kind of problem is being reported for several important groups of marine invertebrates, such as amphipods (9, 10), copepods, crabs, and hermit crabs (11, 12), barnacles (13), abalones (14), echinoderms (5), and polychaetes (8). In some species, intersexuality may include a simultaneous activity of both sexes gonads, in a true hermaphroditic condition (15) or could be induced by pollutants (14).…”

Section: Endocrine Disruption In Marine Invertebrates: General Aspectmentioning

confidence: 99%

Populations Collapses in Marine Invertebrates Due to Endocrine Disruption: A Cause for Concern?

Fernandez

2019

Front. Endocrinol.

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In the beginning of the twenty first century, the International Program on Chemical Safety published a document entitled Global Assessment of the State-Of-The-Science of Endocrine Disruptors. The work indicated only weak evidence of endocrine-related effects in human populations, and in wild animal populations. This document was revised in 2012 (State of the Science of Endocrine Disrupting Chemicals−2012) (1). The new document and the extensive scientific evidence it provided showed clearly that ED effects could be a risk to human and wildlife health. These works, however, were focused in human health and related animal models, mainly vertebrates and particularly mammals. It can be argued that invertebrates and many other taxa are important parts of all ecosystems, and, in many instances, have been shown to be also vulnerable to endocrine disruption. Thus, this work is aimed to show some observations on important marine invertebrate taxa, from an ecological point of view. The most important example of endocrine disruption in marine wild populations is the imposex response of marine gastropods, known for more than 40 years, and worldwide used to evaluate marine antifouling pollution. Among the mollusks, other important natural resources are bivalve species, used as human food sources and cephalopods, free-living, highly specialized mollusks, and also human food sources. Effects derived from endocrine disruptors in these species indicate that consumption could bring these compounds to human populations in an almost direct way, sometimes without any form of cooking or preparation. While discussing these questions, this work is also aimed to stimulate research on endocrine disruption among the invertebrate taxa that inhabited our oceans, and on which these effects are poorly known today.

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Intersexuality in crustaceans: Genetic, individual and population level effects

Cited by 9 publications

References 9 publications

Vitellogenin is not an appropriate biomarker of feminisation in a Crustacean

Vitellogenin is not an appropriate biomarker of feminisation in a Crustacean

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

Populations Collapses in Marine Invertebrates Due to Endocrine Disruption: A Cause for Concern?

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