The Bile Acid Synthesis Pathway Is Present and Functional in the Human Ovary

Background: Bile acids, end products of the pathway for cholesterol elimination, are required for dietary lipid and fat-soluble vitamin absorption and maintain the balance between cholesterol synthesis in the liver and cholesterol excretion. They are composed of a steroid structure and are primarily made in the liver by the oxidation of cholesterol. Cholesterol is also highly abundant in the human ovarian follicle, where it is used in the formation of the sex steroids. Methodology/Principal Findings: Here we describe for the first time evidence that all aspects of the bile acid synthesis pathway are present in the human ovarian follicle, including the enzymes in both the classical and alternative pathways, the nuclear receptors known to regulate the pathway, and the end product bile acids. Furthermore, we provide functional evidence that bile acids are produced by the human follicular granulosa cells in response to cholesterol presence in the culture media. Conclusions/Significance: These findings establish a novel pathway present in the human ovarian follicle that has the capacity to compete directly with sex steroid synthesis

Demographic Diversity and Sustainable Fisheries

Fish species are diverse. For example, some exhibit early maturation while others delay maturation, some adopt semelparous reproductive strategies while others are iteroparous, and some are long-lived and others short-lived. The diversity is likely to have profound effects on fish population dynamics, which in turn has implications for fisheries management. In this study, a simple density-dependent stage-structured population model was used to investigate the effect of life history traits on sustainable yield, population resilience, and the coefficient of variation (CV) of the adult abundance. The study showed that semelparous fish can produce very high sustainable yields, near or above 50% of the carrying capacity, whereas long-lived iteroparous fish can produce very low sustainable yields, which are often much less than 10% of the carrying capacity. The difference is not because of different levels of sustainable fishing mortality rate, but because of difference in the sensitivity of the equilibrium abundance to fishing mortality. On the other hand, the resilience of fish stocks increases from delayed maturation to early maturation strategies but remains almost unchanged from semelparous to long-lived iteroparous. The CV of the adult abundance increases with increased fishing mortality, not because more individuals are recruited into the adult stage (as previous speculated), but because the mean abundance is more sensitive to fishing mortality than its standard deviation. The magnitudes of these effects vary depending on the life history strategies of the fish species involved. It is evident that any past high yield of long-lived iteroparous fish is a transient yield level, and future commercial fisheries should focus more on fish that are short-lived (including semelparous species) with high compensatory capacity

The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni

Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. when they serve as signals for aggression level and/or status. Here, we focus on the function of a conspicuous male ornament in the most species-rich tribe of cichlid fishes, the haplochromines. A characteristic feature of these ca. 1500 species are so-called egg-spots in form of ovoid markings on the anal fins of males, which are made up of carotenoid based pigment cells. It has long been assumed that these yellow, orange or reddish egg-spots play an important role in the courtship and spawning behavior of these maternal mouth-brooding fishes by mimicking the eggs of a conspecific female. The exact function of egg-spots remains unknown, however, and there are several hypotheses about their mode of action. To uncover the function of this cichlid-specific male ornament, we used female mate choice experiments and a male aggression test in the haplochromine species Astatotilapia burtoni. We manipulated the number and arrangement of egg-spots on the anal fins of males, or removed them entirely, and tested (1) female preference with visual contact only using egg-traps, (2) female preference with free contact using paternity testing with microsatellites and (3) male aggression. We found that females did not prefer males with many egg-spots over males with fewer egg-spots and that females tended to prefer males without egg-spots over males with egg-spots. Importantly, males without egg-spots sired clutches with the same fertilization rate as males with egg-spots. In male aggression trials, however, males with fewer egg-spots received significantly more attacks, suggesting that egg-spots are an important signal in intrasexual communication

Dealing with Food and Eggs in Mouthbrooding Cichlids: Structural and Functional Trade-Offs in Fitness Related Traits

As in any vertebrate, heads of fishes are densely packed with functions. These functions often impose conflicting mechanical demands resulting in trade-offs in the species-specific phenotype. When phenotypical traits are linked to gender-specific parental behavior, we expect sexual differences in these trade-offs. This study aims to use mouthbrooding cichlids as an example to test hypotheses on evolutionary trade-offs between intricately linked traits that affect different aspects of fitness. We focused on the oral apparatus, which is not only equipped with features used to feed and breathe, but is also used for the incubation of eggs. We used this approach to study mouthbrooding as part of an integrated functional system with diverging performance requirements and to explore gender-specific selective environments within a species.Because cichlids are morphologically very diverse, we hypothesize that the implications of the added constraint of mouthbrooding will primarily depend on the dominant mode of feeding of the studied species. To test this, we compared the trade-off for two maternal mouthbrooding cichlid species: a "suction feeder" (Haplochromis piceatus) and a "biter" (H. fischeri). The comparison of morphology and performance of both species revealed clear interspecific and intersex differences. Our observation that females have larger heads was interpreted as a possible consequence of the fact that in both the studied species mouthbrooding is done by females only. As hypothesized, the observed sexual dimorphism in head shape is inferred as being suboptimal for some aspects of the feeding performance in each of the studied species. Our comparison also demonstrated that the suction feeding species had smaller egg clutches and more elongated eggs.Our findings support the hypothesis that there is a trade-off between mouthbrooding and feeding performance in the two studied haplochromine cichlids, stressing the importance of including species-specific information at the gender level when addressing interspecific functional/morphological differences

Association and interaction of PPAR-complex gene variants with latent traits of left ventricular diastolic function

<p>Abstract</p> <p>Background</p> <p>Abnormalities in myocardial metabolism and/or regulatory genes have been implicated in left ventricular systolic dysfunction. However, the extent to which these modulate left ventricular diastolic function (LVDF) is uncertain.</p> <p>Methods</p> <p>Independent component analysis was applied to extract latent LVDF traits from 14 measured echocardiography-derived endophenotypes of LVDF in 403 Caucasians. Genetic association was assessed between measured and latent LVDF traits and 64 single nucleotide polymorphisms (SNPs) in three peroxisome proliferator-activated receptor <it>(PPAR)</it>-complex genes involved in the transcriptional regulation of fatty acid metabolism.</p> <p>Results</p> <p>By linear regression analysis, 7 SNPs (4 in <it>PPARA</it>, 2 in <it>PPARGC1A</it>, 1 in <it>PPARG</it>) were significantly associated with the latent LVDF trait, whereas a range of 0-4 SNPs were associated with each of the 14 measured echocardiography-derived endophenotypes. Frequency distribution of <it>P </it>values showed a greater proportion of significant associations with the latent LVDF trait than for the measured endophenotypes, suggesting that analyses of the latent trait improved detection of the genetic underpinnings of LVDF. Ridge regression was applied to investigate within-gene and gene-gene interactions. In the within-gene analysis, there were five significant pair-wise interactions in <it>PPARGC1A </it>and none in <it>PPARA </it>or <it>PPARG</it>. In the gene-gene analysis, significant interactions were found between rs4253655 in <it>PPARA </it>and rs1873532 (p = 0.02) and rs7672915 (p = 0.02), both in <it>PPARGC1A</it>, and between rs1151996 in <it>PPARG </it>and rs4697046 in <it>PPARGC1A </it>(p = 0.01).</p> <p>Conclusions</p> <p>Myocardial metabolism <it>PPAR</it>-complex genes, including within and between genes interactions, may play an important role modulating left ventricular diastolic function.</p

Delimiting the Origin of a B Chromosome by FISH Mapping, Chromosome Painting and DNA Sequence Analysis in Astyanax paranae (Teleostei, Characiformes)

Supernumerary (B) chromosomes have been shown to contain a wide variety of repetitive sequences. For this reason, fluorescent in situ hybridisation (FISH) is a useful tool for ascertaining the origin of these genomic elements, especially when combined with painting from microdissected B chromosomes. In order to investigate the origin of B chromosomes in the fish species Astyanax paranae, these two approaches were used along with PCR amplification of specific DNA sequences obtained from the B chromosomes and its comparison with those residing in the A chromosomes. Remarkably, chromosome painting with the one-arm metacentric B chromosome probe showed hybridization signals on entire B chromosome, while FISH mapping revealed the presence of H1 histone and 18S rDNA genes symmetrically placed in both arms of the B chromosome. These results support the hypothesis that the B chromosome of A. paranae is an isochromosome. Additionally, the chromosome pairs Nos. 2 or 23 are considered the possible B chromosome ancestors since both contain syntenic H1 and 18S rRNA sequences. The analysis of DNA sequence fragments of the histone and rRNA genes obtained from the microdissected B chromosomes showed high similarity with those obtained from 0B individuals, which supports the intraspecific origin of B chromosomes in A. paranae. Finally, the population hereby analysed showed a female-biased B chromosome presence suggesting that B chromosomes in this species could influence sex determinism.This research was funded by grants from the State of São Paulo Research Foundation (FAPESP) to DMZAS (2011/16825-3) and CO (2010/17009-2), grants from National Council for Research and Development (CNPq) to FF and by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)