scholarly journals Can Xenobiotics Alter the Sex Ratio of Crocodilians in the Wild?

2021 ◽  
pp. 1-8
Author(s):  
Satomi Kohno

All crocodilians exhibit temperature-dependent sex determination without sex chromosomes. This temperature dependency can be overridden by exposure to estrogen via estrogen receptor 1. Thus, the sex ratio of crocodilian species is vulnerable to estrogenic xenobiotics. Multiple investigations of the mechanism and effects of xenobiotics in crocodilian species have been conducted since the early 1990s. This review focuses on the impact of xenobiotics on sex determination rather than gonadal functions in crocodilians. The thermosensitive and estrogen-sensitive periods that commit the bipotential gonad to develop as an ovary end by stages 24.5 and 25.3, respectively. In contrast, it is ambiguous when the estrogen-sensitive stage begins for ovarian development, although the thermosensitive period for ovarian development initiates around developmental stage 15 at an extreme female-producing temperature of 30°C. To accurately assess the effect of xenoestrogens on sex ratio in crocodilians, it is critical to collect eggs before the sex-determining period and to incubate them under precisely controlled temperatures. A well-studied system of xenobiotic effects on crocodilians is Lake Apopka (FL, USA), an EPA superfund clean-up site heavily contaminated with Dieldrin, Endrin, and <i>p,p&apos;</i>-DDE. The sum of estimated estrogenicity of xenobiotics measured in Lake Apopka was insufficient to activate the estrogen receptor 1 of <i>Alligator mississippiensis</i>, which is an essential receptor to induce ovarian development. Although juvenile <i>A. mississippiensis</i> showed gonadal alterations in sex hormone production and histology, the environmentally relevant concentration of xenobiotics in Lake Apopka was unlikely to alter the sex ratio of <i>A. mississippiensis.</i> Experimental exposure to xenobiotics such as 17α-ethynylestradiol, <i>p,p&apos;</i>-dichlorodiphenyldichloroethylene, and 2,3,7,8-tetrachlorodibenzodioxin at environmentally relevant concentrations in ovo induced more female offspring in <i>A. mississippiensis</i> as compared with the control group. Bisphenol-A, atrazine, 2,4-dichlorophenoxyacetic acid, endosulfan, and Corexit did not alter the sex ratio of <i>A. mississippiensis</i> or <i>Caiman latirostris</i> under the tested conditions. Egg-incubation temperature has pronounced effects on estrogen sensitivity in crocodilian sex determination. Therefore, crocodilians are vulnerable to xenobiotic contamination and climate change in the wild. It is vital to further investigate the detailed mechanism and effects of environmental xenobiotics in crocodilian sex determination to mitigate their effect on sex ratio and conserve this ancient lineage.

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Maryam Saneipour ◽  
Abdolkarim Sheikhi ◽  
Abbas Moridnia

Background: Breast cancer (BC) is the most common malignant tumor in women around the world. Genetic factors do play a vital role in the development and progression of BC. Genetic alterations in the ESR1 (estrogen receptor 1) gene can lead to estrogen dysfunction and increased risk for BC. Nevertheless, due to genetic diversity, the information from different studies is contradictory and controversial. Objectives: This study aimed to investigate the potential relationship between the rs1801132 and rs2234693 single nucleotide polymorphism (SNPs) of the ESR1 gene with susceptibility to BC in the Iranian population. Methods: The genotyping of the rs2234693 and rs1801132 SNPs was assessed in 63 BC patients referred to Imam Hasan Mojtaba Center, which is a charity-based foundation for cancer care in Dezful, Iran, from March 2018 to November 2019. Also, 65 healthy women were selected as a control group. The genotyping of the SNPs was performed using the high-resolution melting (HRM) technique and confirmed by DNA sequencing. Results: The genotype distribution and allele frequency of the rs2234693 SNP were significantly different in BC patients compared to the control group (genotype frequency with P = 0.018 and allele frequency with P = 0.004, OR = 2.085, 95% CI = 1.253 -3.468). In genetic models, rs2234693 increased BC risk in recessive model (P = 0.005, OR = 2.813, 95% CI = 1.363 - 5.802). However, there was no significant difference regarding genotype distribution of the rs1801132 SNP between the BC patients and controls. Conclusions: Our results showed that the CC genotype of the rs2234693 SNP is significantly associated with BC. Accordingly, it can be suggested that the rs2234693 SNP be considered for susceptibility to BC.


Reproduction ◽  
2007 ◽  
Vol 133 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
H O Goyal ◽  
T D Braden ◽  
P S Cooke ◽  
M A Szewczykowski ◽  
C S Williams ◽  
...  

Previously, we reported an association between estrogen receptor-α (ERα) upregulation and detrimental effects of neonatal diethylstilbestrol (DES) exposure in the rat penis. The objective of this study was to employ the ERα knockout (ERαKO) mouse model to test the hypothesis that ERα mediates DES effects in the developing penis. ERαKO and wild-type C57BL/6 mice received oil or DES at a dose of 0.2 μg/pup per day (0.1 mg/kg) on alternate days from postnatal days 2 to 12. Fertility was tested at 80–240 days of age and tissues were examined at 96–255 days of age. DES caused malformation of the os penis, significant reductions in penile length, diameter, and weight, accumulation of fat cells in the corpora cavernosa penis, and significant reductions in weight of the bulbospongiosus and levator ani muscles in wild-type mice. Conversely, ERαKO mice treated with DES developed none of the above abnormalities. While nine out of ten male mice sired pups in the wild-type/control group, none did in the wild-type/DES group. ERαKO mice, despite normal penile development, are inherently infertile. Both plasma and intratesticular testosterone levels were unaltered in the DES-treated wild-type or DES-treated ERαKO mice when compared with controls, although testosterone concentration was much higher in the ERαKO mice. Hence, the resistance of ERαKO mice to developing penile abnormalities provides unequivocal evidence of an obligatory role for ERα in mediating the harmful effects of neonatal DES exposure in the developing penis.


The various patterns of environmental sex determination in squamates, chelonians and crocodilians are described. High temperatures produce males in lizards and crocodiles but females in chelonians. Original experiments on the effects of incubation at 30 °C (100% females) or 33 °C (100% males) on development in Alligator mississippiensis are described. These include an investigation of the effect of exposing embryos briefly to a different incubation temperature on the sex ratio at hatching, and a study of the effects of 30 °C and 33 °C on growth and development of alligator embryos and gonads. A 7-day pulse of one temperature on the background of another was insufficient to alter the sex ratio dramatically. Incubation at 33 °C increased the rate of growth and development of alligator embryos. In particular, differentiation of the gonad at 33 °C was enhanced compared with 30 °C. A hypothesis is developed to explain the mechanism of temperature-dependent sex determination (TSD) in crocodilians. The processes of primary sex differentiation are considered to involve exposure to a dose of some male-determining factor during a specific quantum of developmental time during early incubation. The gene that encodes for the male- determining factor is considered to have an optimum temperature (33 °C). Any change in the temperature affects the expression o f this gene and affects the dose or quantum embryos are exposed to. In these cases there is production of females by default. The phylogenetic implications of TSD for crocodilians, and reptiles in particular, are related to the life history of the animal from conception to sexual maturity. Those animals that develop under optimal conditions grow fastest and largest and become male. A general association between the size of an animal and its sex is proposed for several types of vertebrate.


2016 ◽  
Vol 52 ◽  
pp. 150-158
Author(s):  
V. N. Balatsky ◽  
L. P. Grishina ◽  
A. M. Saenko ◽  
V. A. Vovk ◽  
P. A. Vaschenko

The speciality of the modern methodology in breeding is using the molecular information, received during genome analysis. This methodology can significantly accelerate the improvement of productivity traits and it is particularly useful in relation to the traits with low coefficient of inheritance while classic methods are not effective enough. The reproductive traits are one of the most important in pig farming, estrogen receptor 1 gene (ESR1) is involved in their control. Meanwhile, the use of ESR1 locus polymorphism in the marker-assisted selection needs to determine the extent of its association with the reproductive traits of animals in those populations where it is planned to conduct such selection. Implementation of marker-assisted selection in Large White and Mirgorod breeds for improving the reproductive traits is an actual task, but a necessary step in this work is the associative analysis. The purpose of the work is to research the association of polymorphisms of ESR1 locus with some reproductive traits of sows of Large White breed (ULW-1 and ULW-3 lines) and sows of Mirgorod breed. Materials and methods of research. Experimental groups: 1) the sows of Large White breed, ULW-3 line, bred in "Bahmutskiy Agrarian Union" farm, Donetsk region; 2) the sows of Large White breed, ULW-1 line, bred in “Stepne” farm, Poltava region; 3) the sows of Mirgorod breed, bred in «Named after Dekabristy» farm, Poltava region. All the experimental animals were previously genotyped on RYR1 gene and had RYR1CC genotype. The animals were genotyped on estrogen receptor 1 locus with aid of PCR-RFLP analysis on PvuII-polymorphic restriction site in the third intron of the gene – DNA marker for estrogen receptor 1 gene. Associations between genotypes and the studied traits were calculated using ANOVA in Excel 2007. Results. ULW-3 sows with ESR1BB genotype turned out to have 1.36 more piglets in a litter (analysing data from 2nd-4th farrows) comparing to animals with ESR1AA genotype. There is a tendency for bigger amount of newborn piglets in the heterozygotes animals than in sows with homozygous ESR1AA. A similar pattern appears in the 1st farrowing, the sows with ESR1BB and ESR1AB genotypes had the advantage in the total number of piglets at birth. In the experimental group of ULW-1 sows statistically proven patterns were not found, there was only a tendency to slight predominance of sows with ESR1BB and ESR1AB genotypes comparing to individuals with ESR1AA genotype. In the experimental group of Mirgorod sows there was a tendency to have most part of individuals with heterozygous genotype. Analysis of prolificacy of ULW-3 sows due to their genotype for the estrogen receptor 1 gene confirmed the superiority of ESR1BB and ESR1AB genotypes comparing to ESR1AA sows. According to 2nd-4th farrows, sows with ESR1BB and ESR1AB genotypes had the advantage in prolificacy comparing to ESR1AA sows by 1.15 and 0.53 piglets, respectively. According to the 1st farrowing difference between genotypes was absent. ESR1/PvuII-polymorphism do es not influence on prolificacy of ULW-1 sows. According to the 1st farrowing the trend towards a higher level of prolificacy of Mirgorod sows with ESR1AA genotype was found, while difference in 2nd-4th farrows between the groups was absent. It was found that ESR1/PvuII-polymorphism impact on the total number of piglets at birth and prolificacy for ULW-3 sows is characterized by predominance of additive component with a little contribution of the dominant component, the similar trend is observed for ULW-1 sows. There is a complex nature of the impact of ESR1/PvuII-polymorphism on the reproductive traits of Mirgorod sows in the predominance of the dominant component. Conclusions. The impact of polymorphism in estrogen receptor 1 gene on the total number of piglets in the litter after the birth and prolificacy in ULW-3 sows was detected. ULW-3 sows with ESR1BB genotype have 1.36 more piglets in a litter (analysing data from 2nd-4th farrows) and 1.15 more comparing to animals with ESR1AA genotype. ESR1/PvuII-polymorphism was not associated with total number of piglets in a litter and prolificacy in ULW-1 sows and Mirgorod sows. The counted parameters of additive-dominant model indicate that ESR1/PvuII polymorphism impact on the total number of piglets at birth and prolificacy for ULW-3 sows is characterized by predominance of additive component with a little contribution of the dominant component.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7164 ◽  
Author(s):  
Suheir Ereqat ◽  
Stéphane Cauchi ◽  
Khaled Eweidat ◽  
Muawiyah Elqadi ◽  
Abedelmajeed Nasereddin

Background Type 2 diabetes mellitus (T2DM) is a multifactorial disease where both genetic and environmental factors contribute to its pathogenesis. The PvuII and XbaI polymorphisms of the estrogen receptor 1 (ESR1) gene have been variably associated with T2DM in several populations. This association has not been studied in the Palestinian population. Therefore, the aim of this study was to investigate the association between the PvuII and XbaI variants in the ESR1 and T2DM and its related metabolic traits among Palestinian women. Methods This case–control study included 102 T2DM and 112 controls in which PvuII and XbaI variants of the ESR1 gene were genotyped using amplicon based next generation sequencing (NGS). Results Allele frequencies of both PvuII and XbaI variants were not significantly different between patients and control subjects (P > 0.05). In logestic regression analysis adjusted for age and BMI, the ESR1 PvuII variant was associated with risk of T2DM in three genotypic models (P < 0.025) but the strongest association was observed under over-dominant model (TT+CC vs. TC) (OR = 2.32, CI [1.18–4.55] adjusted P = 0.013). A similar but non-significant trend was also observed for the ESR1 XbaI variant under the over-dominant model (AA+GG vs. AG) (OR = 2.03, CI [1.05–3.95]; adjusted P = 0.035). The frequencies of the four haplotypes (TA, CG, CA, TG) were not significantly different in the T2DM patients compared with control group (P > 0.025). Among diabetic group, an inverse trend with risk of cardio vascular diseases was shown in carriers of CG haplotype compared to those with TA haplotype (OR = 0.28, CI [0.09–0.90]; adjusted P = 0.035). Further, stratified analyses based on ESR1 PvuII and XbaI genotypes revealed no evidence for association with lipid levels (TC, TG, HDL, LDL). Conclusions This is the first Palestinian study to conclude that ESR1 PuvII and XbaI variants may contribute to diabetes susceptibility in Palestinian women. Identification of genetic risk markers can be used in defining high risk subjects and in prevention trials.


2013 ◽  
Vol 82 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Sylwia Jarmołowicz ◽  
Krystyna Demska-Zakęś ◽  
Zdzisław Zakęś

Phthalic acid, di-n-butyl ester known as di-n-butyl phthalate, is an organic chemical compound that belongs to the group of endocrine disruptor compounds that have a documented negative impact on mammalian endocrine systems. Di-n-butyl phthalate is used widely as a plasticizer in the manufacture of artificial materials, which is why it is found in all types of environmental samples including those from water basins. The aim of the study was to describe the impact of di-n-butyl phthalate on the development of the reproductive system of European pikeperch (Sander lucioperca) during the sex differentiation period (age 61–96 days post hatch). A total of 240 fish were divided into 6 groups (40 fish per tank). Treatments consisted of a control group (0 g di-n-butyl phthalate·kg-1 feed) and five trial groups with 0.125, 0.25, 0.5, 1, and 2 g di-n-butyl phthalate·kg-1 feed, respectively. Histological changes of the fish gonads, sex ratio, survival and growth of fish were evaluated. Di-n-butyl phthalate seriously disturbed sex differentiation process of pikeperch. Histopathological analyses revealed that the administration of 2 g di-n-butyl phthalate·kg-1 significantly affected the sex ratio. The feminization process (intersex gonads) at concentrations of 1 g and 2 g di-n-butyl phthalate·kg-1 were observed. All analyzed concentrations delayed testicular development. Phthalate did not have a significant impact on the survival or growth rates of the pikeperch. This is the first report of disruption sex differentiation processes in fish by di-n-butyl phthalate.


2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Qiong Gao ◽  
Elena López-Knowles ◽  
Maggie Chon U Cheang ◽  
James Morden ◽  
Ricardo Ribas ◽  
...  

Abstract To investigate the impact of sampling methodology on gene expression data from primary estrogen receptor–positive (ER+) breast cancer biopsies, global gene expression was measured in core-cut biopsies at baseline and surgery from patients randomly assigned to receive either two weeks of presurgical aromatase inhibitor (AI; n = 157) or no presurgical treatment (n = 56). Those genes most markedly altered in the AI group (eg, FOS, DUSP1, RGS1, FOSB) were similarly altered in the no treatment group; some widely investigated genes that were apparently unaffected in the AI group (eg, MYC) were counter-altered in the control group, masking actual AI-dependent changes. In the absence of a control group, these artefactual changes would likely lead to the most affected genes being the erroneous focus of research. The findings are likely relevant to all archival collections of ER+ breast cancer.


Author(s):  
Gitanjali Kapoor ◽  
Dinesh Kumar

Background: Sex ratio is defined as the number of females per thousand males. The objectives were to study the knowledge, attitude and the practice of pregnant women on gender preference, prenatal sex determination and female feticide.Methods: It was a hospital based cross-sectional study. The present study was undertaken among the 204 newly registered pregnant women attending the hospital in Marh block of Jammu district, Jammu and Kashmir, India. A pre-designed, pre-tested and structured questionnaire was used in the study. The data collection technique was a personnel interview of the study subjects.Results: The mean age of study subjects was 25.39±3.6 years. A majority (75.5%) of the pregnant women did not show any gender preference, followed by male preference (13.73%) and female preference (10.78%). Only 70.59% and 67.65%, of the total subjects were aware that prenatal sex determination and female feticide are illegal, respectively. Awareness regarding prenatal sex determination and female feticide increased with the level of education.Conclusions: There is a need to educate pregnant women about the impact of negative sex ratio on the society and about the penalization for violation of the PCPNDT act.


2020 ◽  
Vol 10 (4) ◽  
pp. 1402 ◽  
Author(s):  
Tayebeh Enayat Gholampour ◽  
Raha Fadaei Raieni ◽  
Mojtaba Pouladi ◽  
Mohamad Larijani ◽  
Maria Pagano ◽  
...  

The main purpose of this study was to consider the impact of Vitex agnus-castus hydroalcoholic extract, containing phytoestrogenic compounds on growth indices, sex ratio and histology of gonads of female Zebrafish. Fish larvae (4-day-old after hatching) were nourished with investigational diets (0 (control group T0), 5 g (T1), 10 g (T2) and 15 g (T3) kg−1 food) from first active feeding for 90 days. The results showed that Condition Factor (CF), Food Conversion Rate (FCR), Body Weight Gain (BWG), and Specific Growth Rate (SGR) were affected meaningfully by hydroalcoholic extract of Vitex agnus-castus (p < 0.05). These factors were significantly higher in compare to T3 treatment (p < 0.05). With increasing concentration of the extract in the diet, the ratio of female to male increased Treatment of T3 resulted in 87.23% feminization. Overall, this study suggests the use of T3 treatment achieves the best reproduction performance and a higher percentage of females in zebrafish as a model for aquaculture species. According to the results, the lowest levels of glucose and cholesterol were observed in T3 treatment and showed a significant changes with the control and treatments (p < 0.05).


2020 ◽  
Vol 287 (1926) ◽  
pp. 20200210
Author(s):  
Samantha L. Bock ◽  
Russell H. Lowers ◽  
Thomas R. Rainwater ◽  
Eric Stolen ◽  
John M. Drake ◽  
...  

Species displaying temperature-dependent sex determination (TSD) are especially vulnerable to the effects of a rapidly changing global climate due to their profound sensitivity to thermal cues during development. Predicting the consequences of climate change for these species, including skewed offspring sex ratios, depends on understanding how climatic factors interface with features of maternal nesting behaviour to shape the developmental environment. Here, we measure thermal profiles in 86 nests at two geographically distinct sites in the northern and southern regions of the American alligator's ( Alligator mississippiensis ) geographical range, and examine the influence of both climatic factors and maternally driven nest characteristics on nest temperature variation. Changes in daily maximum air temperatures drive annual trends in nest temperatures, while variation in individual nest temperatures is also related to local habitat factors and microclimate characteristics. Without any compensatory nesting behaviours, nest temperatures are projected to increase by 1.6–3.7°C by the year 2100, and these changes are predicted to have dramatic consequences for offspring sex ratios. Exact sex ratio outcomes vary widely depending on site and emission scenario as a function of the unique temperature-by-sex reaction norm exhibited by all crocodilians. By revealing the ecological drivers of nest temperature variation in the American alligator, this study provides important insights into the potential consequences of climate change for crocodilian species, many of which are already threatened by extinction.


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