Reduced Survival and Disruption of Female Reproductive Output in Two Copepod Species (Acartia clausi and A. tonsa) Exposed to the Model Endocrine Disruptor 17α-Ethinylestradiol

Estuaries are heavily impacted by pollutants from different sources such as urban sewage, industrial waste and agricultural runoff. Endocrine-disrupting chemicals (EDCs) are very concerning pollutants to estuarine wildlife, but little is known about their impact on microscopic biota such as zooplankton. The aim of this work was to investigate the effects of a model EDC, the 17α-ethinylestradiol (EE2), on two copepod species inhabiting the Basque coast (Southeastern Bay of Biscay) estuaries: Acartia clausi (autochthonous neritic species) and Acartia tonsa (non-indigenous brackish species). Female copepods were collected at population maximum time (spring for A. clausi and summer for A. tonsa) and exposed individually to 5 ng/L (low), 5 µg/L (medium) and 500 µg/L EE2 (high) doses, from environmental concentrations found in sewage effluents to toxicological concentrations. After 24 h exposure, the survival rate of experimental individuals was checked and the lethal concentration LC50 was calculated. The number of egg-producing females and the amount of egg laying and egg hatching were recorded. The integrated biomarker index (IBR) was calculated to integrate the overall effects of EE2 exposure. Both species had reduced survival rates at 500 µg/L, and the LC50 was lower in A. tonsa (158 µg/L) compared to A. clausi (398 µg/L). The number of eggs laid was significantly reduced in A. clausi at EE2 medium and high doses, while a reduction in the number of eggs in A. tonsa was observed only at the high dose. However, no significant differences were detected in the egg hatching success of exposed A. clausi and A. tonsa. IBR index showed that EE2 had the most detrimental effects on A. tonsa and A. clausi females at the 500 µg/L dose. In conclusion, after 24 h of exposure, EE2 reduced female copepod survival and disrupted reproductive output, but only at high non-environmentally relevant concentrations.Funded by the Basque Government (IT1743-22) and UPV/EHU (UFI 11/37). T.H. was a holder of an Erasmus Mundus master grant

Use of otolith shape and elemental signatures to infer the population structure of the Thicklip Grey Mullet Chelon labrosus in the Southern Bay of Biscay

Xenoestrogenic effects have been reported in thicklip grey mullet, Chelon labrosus, used as pollution sentinel organisms in estuaries in the Southeast Bay of Biscay with intersex gonads described in populations from some contaminated estuaries. Despite evidence of reproductive stress in this catadromous fish species, knowledge of mullet reproductive movements and connectivity between estuaries is lacking. This study investigates the population structure of C. labrosus using otolith shape and elemental signatures of 60 adult individuals collected from two estuaries found in the Southeast Bay of Biscay (Gernika and Plentzia). All samples were collected in June–July 2020. Otolith shape analysis was determined using elliptical Fourier descriptors, while elemental signatures (Sr:Ca, Li:Ca, Mg:Ca, Mn:Ca, Co:Ca, Ni:Ca, Cu:Ca and Ba:Ca) of whole sagittae were determined by inductively coupled plasma mass spectrophotometry. Both natural tags were analyzed with univariate and multivariate statistics to determine whether these signatures are geographically distinct and can be used to assess the degree of separation between individuals. The data showed significant differences in the otolith shape and elemental analyses, with canonical analysis of principal coordinates plots identifying two different groups, each one belonging to each estuary of origin. Differences in whole otolith elemental signatures between locations were driven by Sr:Ca, Li:Ca, and Ba:Ca. Sr:Ca and Li:Ca ratios were higher in Plentzia than in Gernika, while Ba:Ca was higher in Gernika. The high re-classification success rate using both tools obtained from stepwise linear discriminant function analysis supports these findings and suggests that Gernika and Plentzia individuals passed enough time in separated water compartments and should be regarded as two different population units. This could suggest that the intersex condition in mullets from Gernika is due to life-long exposure to xenoestrogens after homing during early larval development in that estuary, without migrations to other estuaries.info:eu-repo/semantics/publishedVersio

High production of transfer RNAs identifies the presence of developing oocytes in ovaries and intersex testes of teleost fish

5S rRNA is highly transcribed in fish oocytes and this transcription levels can be used to identify the presence of oocytes in the intersex testes of fish exposed to xenoestrogens. Similar to 5S rRNA, tRNAs are transcribed by RNA polymerase III (Pol-III) in eukaryotes, so this study focuses in the analysis of the levels of expression of tRNAs in the gonads (ovaries and testes) of eight teleost species as a possible new oocyte molecular marker. Total RNA extracted from gonads of six commercial teleost species in the Biscay Bay, from the pollution sentinel species thicklip grey mullet (Chelon labrosus) known present intersex testes in response to xenoestrogens in Gernika estuary and from the laboratory model species Danio rerio were analysed through capillary electrophoresis. Bioanalyzer electropherograms were used to quantify the concentrations of tRNAs, 5S and 5.8S rRNA. All studied ovaries expressed significantly higher levels of tRNAs and 5S rRNA than testes. A tRNA to 5.8S rRNA index was calculated which differentiates ovaries from testes, and identifies some intersex testes in between testes and ovaries in mullets. The tRNA/5.8S ratio was highest in ovaries in previtellogenic stage, decreasing towards maturity. Thus, strong oocyte expression of tRNAs is an additional proof of high activity levels of Pol-III during early stages of oocyte development in teleost ovaries. Incidentally, we observed that miRNA concentrations were always higher in testes than ovaries. The indexing approach developed in the present study could have multiple applications in teleost reproduction research and in the development of early molecular markers of intersex condition.This work has been supported by project Born2bEgg (Spanish MCIN & EU-FEDER/ERDF (PGC2018-101442-B-100) and by the grants to consolidated research projects of the Basque Government (IT1302-19 and IT1743-22). We are thankful to the Biscay Bay Environmental Biospecimen Bank (BBEBB; PiE-UPV/EHU) for providing mullet tissues

Lack of genetic structure in euryhaline Chelon labrosus from the estuaries under anthropic pressure in the Southern Bay of Biscay to the coastal waters of the Mediterranean Sea

Over the last decade, xenoestrogenic effects have been reported in populations of thicklip grey mullet Chelon labrosus from contaminated estuaries in the Bay of Biscay, resulting in intersex condition. To understand the level of gene flow in individuals of different Basque estuaries microsatellite markers were used to evaluate the population structure and connectivity of C. labrosus from estuaries of the Basque coast. 46 microsatellites were tested and 10 validated for the analysis of 204 individuals collected from 5 selected Basque estuaries and 2 outgroups in the Bay of Cadiz and Thermaic Gulf. The polymorphic microsatellites revealed 74 total alleles, 2–19 alleles per locus. The mean observed heterozygosity (0.49 ± 0.02) was lower than the expected one (0.53 ± 0.01). There was no evidence of genetic differentiation (FST = 0.0098, P = 0.0000) among individuals or sites. Bayesian clustering analysis revealed a single population in all sampled locations. The results of this study indicate widespread genetic homogeneity and panmixia of C. labrosus across the current sampling areas spanning the Atlantic and Mediterranean basins. The hypothesis of panmixia could therefore be well supported so individuals inhabiting estuaries with high prevalence of intersex condition should be considered as members of the same single genetic group as those inhabiting adjacent estuaries without incidence of xenoestrogenicity.This work was funded by the Spanish Ministry of Science. Innovation and Universities and EU-FEDER/ERDF (BORN2bEGG PGC2018-101442-B-I00) and the Basque Government (Grants to consolidated research groups IT1302-19 and IT1743-22). A.N. is a recipient of a pre-doctoral grant PIF17/172 from the University of the Basque Country (UPV/EHU). Authors wish to thank the help of two anonymous reviewers for significantly helping in better focusing the aim of the present work

Mugilid Fish Are Sentinels of Exposure to Endocrine Disrupting Compounds in Coastal and Estuarine Environments

Effects on fish reproduction can result from a variety of toxicity mechanisms first operating at the molecular level. Notably, the presence in the environment of some compounds termed endocrine disrupting chemicals (EDCs) can cause adverse effects on reproduction by interfering with the endocrine system. In some cases, exposure to EDCs leads to the animal feminization and male fish may develop oocytes in testis (intersex condition). Mugilid fish are well suited sentinel organisms to study the effects of reproductive EDCs in the monitoring of estuarine/marine environments. Up-regulation of aromatases and vitellogenins in males and juveniles and the presence of intersex individuals have been described in a wide array of mullet species worldwide. There is a need to develop new molecular markers to identify early feminization responses and intersex condition in fish populations, studying mechanisms that regulate gonad differentiation under exposure to xenoestrogens. Interestingly, an electrophoresis of gonad RNA, shows a strong expression of 5S rRNA in oocytes, indicating the potential of 5S rRNA and its regulating proteins to become useful molecular makers of oocyte presence in testis. Therefore, the use of these oocyte markers to sex and identify intersex mullets could constitute powerful molecular biomarkers to assess xenoestrogenicity in field conditions.This work has been funded through research projects of the Spanish MINECO (SEXOVUM AGL2012-33477), Basque Government (SAIOTEK OVUM-II S-PE12UN086 and Consolidated research groups IT-810-13) and UPV/EHU (UFI 11/37). IRB is recipient of a predoctoral grant of the Basque Government while CB is recipient of a grant of UPV/EHU

Ehunen biologia

184 p.Lan honek hauxe du xede: Biozientziak (Biologia, Biokimika eta Biologia Molekularra, Bioteknologia eta Medikuntza) ikasten ari diren ikasleei Ehunen Biologia arloan testuliburu egoki eta erabilgarri bat eskaintzea. Histologia alorrean, liburu eta atlas histologiko ugari daude argitaratuta, baina ikasleei beren apunteak osatzeko euskarazko ikasmateriala sortzea izan da gure asmoa. Liburu honetan, animalien eta landareen ehun nagusiak deskribatzen dira. Testuan zehar emandako informazioa ulergarriagoa izan dadin, ikonografia eta mikroargazki lagungarriak aukeratu dira. Amaieran, gai bakoitzean agertzen diren termino nagusiak definitzen dituen glosarioa gehitu da. Azkenengo atalean, bibliografia zerrendatu da, eta Ehunen Biologian informazio-iturri moduan erabili daitezkeen testuliburu, artikulu eta web orriak ageri dira. Lan hau lau atal nagusitan dago banatuta: Garapenaren Zelulen Biologia, Animalia Histologia, Landare Histologia eta Metodoak eta Teknikak Histologian. Ehunen jatorri enbrionarioa deskribatzen duen hasierako atal horretan, animaliengan enbriogenesian zehar gertatzen diren desberdintzapen-prozesu goiztiarrak azaltzen dira. Ondoren, ornodunetan aurkitu daitezkeen lau ehun nagusiak lantzen dira, hau da, epitelioa, ehun konektiboa, muskulua eta nerbioa. Ehun bakoitzaren ezaugarri nagusiak eta osagaiak deskribatzen dira. Gainera, honako hauek modu zehatzean aurkezten dira: zelula motak, antolaketa mailak, garapena eta desberdintzapena, berreraketa, funtzioak eta beste ehunekiko duten erlazioa zein organoen eraketan nola hartzen duten parte. Ornodunen ehunez gain, ornogabeetan agertzen diren ehun berezi nagusiak deskribatzen dira. Landareen histologiari dagokion atalean, egitura nagusiak eta zelula-motak azaltzen dira. Azkenik, egitura histologikoen azterketarako erabiltzen diren metodo eta prozesamendu arruntenak deskribatzen dira

Ekosistemen osasuna: klima-aldaketaren eta kutsaduraren arteko elkarrekintza

Tresna biologiko berriak behar dira klima-aldaketak lurzoruetako zein ekosistema itsastarretako organismoengan eragiten duen efektua aztertzeko. Asmo honekin Zelulen Biologia Ingurumen Toxikologian ikerketa-taldea, estres peko egonaldiaren, eragindako efektuen eta osasun-estatusaren biomarkatzaileak ugal-zikloan zehar garatzen eta aplikatzen ari da, ekosistema desberdinetako espezie sentikor zentineletan. Artikulu honetan ekosistemen osasunaren eta bere ebaluazioari buruzko auziaren egoera izan dugu ikusmiran klima-aldaketaren ikuspuntutik, eta etorkizunerako lan ildoak proposatu ditugu

Ekosistemen osasuna: klima-aldaketaren eta kutsaduraren arteko elkarrekintza

Tresna biologiko berriak behar dira klima-aldaketak lurzoruetako zein ekosistema itsastarretako organismoengan eragiten duen efektua aztertzeko. Asmo honekin Zelulen Biologia Ingurumen Toxikologian ikerketa-taldea, estres peko egonaldiaren, eragindako efektuen eta osasun-estatusaren biomarkatzaileak ugal-zikloan zehar garatzen eta aplikatzen ari da, ekosistema desberdinetako espezie sentikor zentineletan. Artikulu honetan ekosistemen osasunaren eta bere ebaluazioari buruzko auziaren egoera izan dugu ikusmiran klima-aldaketaren ikuspuntutik, eta etorkizunerako lan ildoak proposatu ditugu

Ehunen biologia

184 p.Lan honek hauxe du xede: Biozientziak (Biologia, Biokimika eta Biologia Molekularra, Bioteknologia eta Medikuntza) ikasten ari diren ikasleei Ehunen Biologia arloan testuliburu egoki eta erabilgarri bat eskaintzea. Histologia alorrean, liburu eta atlas histologiko ugari daude argitaratuta, baina ikasleei beren apunteak osatzeko euskarazko ikasmateriala sortzea izan da gure asmoa. Liburu honetan, animalien eta landareen ehun nagusiak deskribatzen dira. Testuan zehar emandako informazioa ulergarriagoa izan dadin, ikonografia eta mikroargazki lagungarriak aukeratu dira. Amaieran, gai bakoitzean agertzen diren termino nagusiak definitzen dituen glosarioa gehitu da. Azkenengo atalean, bibliografia zerrendatu da, eta Ehunen Biologian informazio-iturri moduan erabili daitezkeen testuliburu, artikulu eta web orriak ageri dira. Lan hau lau atal nagusitan dago banatuta: Garapenaren Zelulen Biologia, Animalia Histologia, Landare Histologia eta Metodoak eta Teknikak Histologian. Ehunen jatorri enbrionarioa deskribatzen duen hasierako atal horretan, animaliengan enbriogenesian zehar gertatzen diren desberdintzapen-prozesu goiztiarrak azaltzen dira. Ondoren, ornodunetan aurkitu daitezkeen lau ehun nagusiak lantzen dira, hau da, epitelioa, ehun konektiboa, muskulua eta nerbioa. Ehun bakoitzaren ezaugarri nagusiak eta osagaiak deskribatzen dira. Gainera, honako hauek modu zehatzean aurkezten dira: zelula motak, antolaketa mailak, garapena eta desberdintzapena, berreraketa, funtzioak eta beste ehunekiko duten erlazioa zein organoen eraketan nola hartzen duten parte. Ornodunen ehunez gain, ornogabeetan agertzen diren ehun berezi nagusiak deskribatzen dira. Landareen histologiari dagokion atalean, egitura nagusiak eta zelula-motak azaltzen dira. Azkenik, egitura histologikoen azterketarako erabiltzen diren metodo eta prozesamendu arruntenak deskribatzen dira