Fundulus heteroclitus: Ovarian reproductive physiology and the impact of environmental contaminants

2011 ◽  
Vol 154 (4) ◽  
pp. 278-287 ◽  
Author(s):  
Andrea L. Lister ◽  
Glen J. Van Der Kraak ◽  
Robert Rutherford ◽  
Deborah MacLatchy
Keyword(s):  
Fundulus Heteroclitus ◽  
Environmental Contaminants ◽  
Reproductive Physiology ◽  
The Impact

Adaptations of wild populations of the estuarine fish Fundulus heteroclitus to persistent environmental contaminants

1999 ◽  
Vol 134 (1) ◽  
pp. 9-17 ◽  
Author(s):  
D. Nacci ◽  
L. Coiro ◽  
D. Champlin ◽  
S. Jayaraman ◽  
R. McKinney ◽  
...  
Keyword(s):  
Fundulus Heteroclitus ◽  
Environmental Contaminants ◽  
Estuarine Fish ◽  
Wild Populations

scholarly journals Iodine and Pregnancy

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Christina Yarrington ◽  
Elizabeth N. Pearce
Keyword(s):  
Thyroid Hormone ◽  
Pregnant Women ◽  
Thyroid Function ◽  
Environmental Contaminants ◽  
Iodine Status ◽  
Nutritional Recommendations ◽  
Iodine Metabolism ◽  
The Impact ◽  
In Pregnancy

Iodine is a necessary element for the production of thyroid hormone. We will review the impact of dietary iodine status on thyroid function in pregnancy. We will discuss iodine metabolism, homeostasis, and nutritional recommendations for pregnancy. We will also discuss the possible effects of environmental contaminants on iodine utilization in pregnant women.

scholarly journals Information theory and the neuropeptidergic regulation of seasonal reproduction in mammals and birds

2011 ◽  
Vol 278 (1717) ◽  
pp. 2477-2485 ◽  
Author(s):  
Tyler J. Stevenson ◽  
Gregory F. Ball
Keyword(s):  
Mammalian Species ◽  
Reproductive Physiology ◽  
Environmental Cues ◽  
Naturally Occurring ◽  
Contingency Model ◽  
Neural Integration ◽  
Gonadotrophin Releasing Hormone ◽  
Environmental Amelioration ◽  
The Impact ◽  
The Brain

Seasonal breeding in the temperate zone is a dramatic example of a naturally occurring change in physiology and behaviour. Cues that predict periods of environmental amelioration favourable for breeding must be processed by the brain so that the appropriate responses in reproductive physiology can be implemented. The neural integration of several environmental cues converges on discrete hypothalamic neurons in order to regulate reproductive physiology. Gonadotrophin-releasing hormone-1 (GnRH1) and Kisspeptin (Kiss1) neurons in avian and mammalian species, respectively, show marked variation in expression that is positively associated with breeding state. We applied the constancy/contingency model of predictability to investigate how GnRH1 and Kiss1 integrate different environmental cues to regulate reproduction. We show that variation in GnRH1 from a highly seasonal avian species exhibits a predictive change that is primarily based on contingency information. Opportunistic species have low measures of predictability and exhibit a greater contribution of constancy information that is sex-dependent. In hamsters, Kiss1 exhibited a predictive change in expression that was predominantly contingency information and is anatomically localized. The model applied here provides a framework for studies geared towards determining the impact of variation in climate patterns to reproductive success in vertebrate species.

Impact of photoperiodic exposures during late gestation and lactation periods on the pineal and reproductive physiology of the Indian palm squirrel, Funambulus pennanti

Reproduction ◽  
2000 ◽  
pp. 295-301 ◽  
Author(s):  
KS Bishnupuri ◽  
C Haldar
Keyword(s):  
Pineal Gland ◽  
Recovery Process ◽  
Reproductive Physiology ◽  
Late Gestation ◽  
Constant Light ◽  
Constant Darkness ◽  
Lactation Period ◽  
Postpartum Recovery ◽  
The Impact ◽  
Constant Dark

Studies on the maternal transfer of photoperiodic information in mammals indicate that the daily photoperiod perceived by the mother during the gestation-lactation period is communicated to the fetus either through the placenta or via the milk. However, the impact of photoperiodic exposures during gestation and lactation on the maternal pineal and reproductive physiology has not been reported for any tropical rodent. The exposure of pregnant female Indian palm squirrels (Funambulus pennanti) to constant light (24 h light:0 h dark), constant dark (0 h light:24 h dark), long daylength (14 h light:10 h dark) or short daylength (10 h light:14 h dark) during early gestation (< 30 days) resulted in the resorption of pregnancy, while during late gestation (> 30 days), it did not interfere with the maintenance of pregnancy. Alterations in photoperiodic condition during late gestation and lactation altered the postpartum recovery process. Pineal gland activity, as assessed by pineal mass, protein content and plasma melatonin, was lowest during the breeding phase, but increased gradually after parturition until the next breeding phase. During gestation and lactation, constant light, long daylength and short daylength conditions were less effective, while constant dark condition had a profound effect in depressing pineal gland activity, which subsequently advanced postpartum recovery. Hence, lactating females under constant darkness prepare themselves for next mating much earlier than females under natural daylength (12 h light:12 h dark) conditions. Therefore, photoperiodic information, mediated via the pineal gland, may be important for maintaining gestation physiology as well as postpartum recovery in female rodents.

Developmental changes in circulatory vitamin A (retinol) and its transport proteins in free-ranging harbour seal (Phoca vitulina) pups

2000 ◽  
Vol 78 (10) ◽  
pp. 1862-1868 ◽  
Author(s):  
Wendy Simms ◽  
Peter S Ross
Keyword(s):  
Vitamin A ◽  
Marine Mammals ◽  
Environmental Contaminants ◽  
Phoca Vitulina ◽  
Transport Proteins ◽  
Developmental Changes ◽  
Harbour Seal ◽  
Retinol Binding Protein ◽  
Free Ranging ◽  
The Impact

Although vitamin A (retinol) levels are highly regulated within individual organisms, natural (e.g., age, sex, disease) and anthropogenic (e.g., environmental contaminants) factors can affect the dynamics of this essential nutrient. In this study, we examined developmental changes in the circulatory vitamin A system of free-ranging harbour seal (Phoca vitulina) pups by collecting serial blood samples from healthy known-age animals throughout their nursing period. While harbour seal pups were born with relatively low levels of circulatory retinol (144.4 ± 13.9 µg/L), nursing animals more than doubled these levels within 2 days (385.0 ± 46.9 µg/L), and levels continued to rise more gradually until weaning (431.0 ± 35.8 µg/L). Animals that were not nursing, such as orphaned (184.4 ± 34.2 µg/L), fasted (347.0 ± 14.4 µg/L), and weaned (204.5 ± 38.5 µg/L) pups, had significantly lower circulatory retinol levels. Despite the developmental changes observed in total retinol, the concentration of retinol bound by its transport proteins, retinol binding protein and transthyretin, remained relatively constant throughout the nursing period. This suggests that, like most mammals, the delivery of retinol to target tissues is highly regulated in harbour seal pups. Furthermore, the high concentrations of circulatory retinol observed in harbour seal pups may serve to saturate transport proteins, ensuring a steady delivery of vitamin A to target tissues during a period of potentially variable supply. Understanding how natural factors affect circulatory retinol and its transport proteins is an important facet of assessing the impact of environmental contaminants on vitamin A dynamics in marine mammals.

scholarly journals Using a Silica Substrate to Monitor the Effectiveness of Radiocarbon Pretreatment

Radiocarbon ◽  
2011 ◽  
Vol 53 (4) ◽  
pp. 705-711 ◽  
Author(s):  
M W Dee ◽  
F Brock ◽  
A D Bowles ◽  
C Bronk Ramsey
Keyword(s):  
High Precision ◽  
Environmental Contaminants ◽  
Compositional Analysis ◽  
Sample Material ◽  
Acid Base ◽  
Carbon Contamination ◽  
Silica Substrate ◽  
Large Numbers ◽  
The Impact ◽  
Solvent Wash

The objective of radiocarbon pretreatment is to eliminate any contaminant carbon from the sample material. Solvent washes and acid-base-acid (ABA) procedures are widely used for this purpose. However, quantitatively analyzing their effectiveness is surprisingly problematic, as it often requires large numbers of 14C measurements or high-precision compositional analysis. The technique presented here involves monitoring the impact of different forms of contamination by measuring their adherence to a non-carbonaceous substrate called Chromosorb®. Firstly, the substrate was used in place of a 14C sample in order to monitor the accrual of carbon contamination during a standard solvent wash and ABA pretreatment. This produced a contamination profile against which modifications to the pretreatment procedure could be compared. Secondly, stocks were prepared of Chromosorb that had been infused with environmental contaminants and with common glues, adhesives, and preservatives. By monitoring the elimination of carbon from these stocks, the effectiveness of different pretreatment procedures could be evaluated and the most problematic of the contaminants for 14C dating could be identified.

scholarly journals Distinguishing among modes of convergent adaptation using population genomic data

2017 ◽  
Author(s):  
Kristin M. Lee ◽  
Graham Coop
Keyword(s):  
Gene Flow ◽  
Fundulus Heteroclitus ◽  
Copper Toxicity ◽  
Genomic Data ◽  
Composite Likelihood ◽  
Allele Frequencies ◽  
Standing Variation ◽  
Genome Wide ◽  
Genetic Level ◽  
The Impact

AbstractGeographically separated populations can convergently adapt to the same selection pressure. Convergent evolution at the level of a gene may arise via three distinct modes. The selected alleles can (1) have multiple independent mutational origins, (2) be shared due to shared ancestral standing variation, or (3) spread throughout subpopulations via gene flow. We present a model-based, statistical approach that utilizes genomic data to detect cases of convergent adaptation at the genetic level, identify the loci involved and distinguish among these modes. To understand the impact of convergent positive selection on neutral diversity at linked loci, we make use of the fact that hitchhiking can be modeled as an increase in the variance in neutral allele frequencies around a selected site within a population. We build on coalescent theory to show how shared hitchhiking events between subpopulations act to increase covariance in allele frequencies between subpopulations at loci near the selected site, and extend this theory under different models of migration and selection on the same standing variation. We incorporate this hitchhiking effect into a multivariate normal model of allele frequencies that also accounts for population structure. Based on this theory, we present a composite-likelihood-based approach that utilizes genomic data to identify loci involved in convergence, and distinguishes among alternate modes of convergent adaptation. We illustrate our method on genome-wide polymorphism data from two distinct cases of convergent adaptation. First, we investigate the adaptation for copper toxicity tolerance in two populations of the common yellow monkey flower, Mimulus guttatus. We show that selection has occurred on an allele that has been standing in these populations prior to the onset of copper mining in this region. Lastly, we apply our method to data from four populations of the killifish, Fundulus heteroclitus, that show very rapid convergent adaptation for tolerance to industrial pollutants. Here, we identify a single locus at which both independent mutation events and selection on an allele shared via gene flow, either slightly before or during selection, play a role in adaptation across the species’ range.

Sign in / Sign up

Export Citation Format

Share Document