An Investigation of the Tissue Distribution of Lead in Steelhead Trout

Lead is a metal that interferes with a variety of body processes and is toxic to many organs in humans and other animals. There is a legacy of lead pollution in the waterways of Western New York (WNY). Fish consumption advisories in WNY are partially based on the danger of lead contamination. However, it is not always clear if tissues of the fish that are commonly consumed are as highly contaminated as less commonly consumed tissues. In collaboration with a research team from D’Youville College, we investigated the lead concentration in different tissues of nine steelhead trout caught in the Lower Niagara River. The fish were dissected, and samples of each of the following tissue types were collected: muscle (fillet), liver, gonad, and spleen. Samples were dissolved in nitric acid to release the lead into solution. An Atomic Absorption Spectrometer (AAS) with a graphite furnace module was used to measure lead in the samples to part per million levels. The lead concentrations in each tissue were averaged. Our results show a near to no detection for lead concentrations using our method. While it is encouraging that the fish appear to have very low levels of lead in their tissue, we were not able to conclude that any tissues are less contaminated than others. Future work will focus on contaminants that are expected to be at detectable concentrations based on fish consumption advisory data

Analysis of Oncorhynchus Mykiss Tissue to Determine Lead Ion Concentration

The variation in potential lead ion (Pb +2) concentration in various tissue samples of Oncorhynchus Mykiss (steelhead) trout caught in the Niagara River was investigated. This was used to develop a kinetic model of trace element bioaccumulation of lead in various tissues. By employing experimentally determined trace element influx and efflux from environmental food and water exposures, lead ion concentrations were determined using atomic absorption spectroscopy on homogenized fillet, liver, and gonad tissues collected from steelhead trout caught in the Niagara River. Lead ion concentrations were also determined from water samples collected at a GPS noted catch site. All sample testing was conducted under the direction of Dr. David Stewart, Ph.D. at D’Youville College Results from the study may be used to predict the level of lead ion exposure to humans through the consumption of the steelhead trout fillets and may be used predict the environmental conditions of lead accumulation in human food sources caught in local waters, such as Lake Erie, the Niagara River, and Lake Ontario. Lead measurements may suggest (a) accumulation of lead concentration in steelhead trout fillet tissue consumed by humans, and (b) processes of influx and efflux governing bioaccumulation in these animals in their natural environment, such as accumulation in the fish from ingested particles, or accumulation mostly through the food web, or that the relative accumulation varies with environmental conditions

Sexually Antagonistic “Zygotic Drive” of the Sex Chromosomes

Genomic conflict is perplexing because it causes the fitness of a species to decline rather than improve. Many diverse forms of genomic conflict have been identified, but this extant tally may be incomplete. Here, we show that the unusual characteristics of the sex chromosomes can, in principle, lead to a previously unappreciated form of sexual genomic conflict. The phenomenon occurs because there is selection in the heterogametic sex for sex-linked mutations that harm the sex of offspring that does not carry them, whenever there is competition among siblings. This harmful phenotype can be expressed as an antagonistic green-beard effect that is mediated by epigenetic parental effects, parental investment, and/or interactions among siblings. We call this form of genomic conflict sexually antagonistic “zygotic drive”, because it is functionally equivalent to meiotic drive, except that it operates during the zygotic and postzygotic stages of the life cycle rather than the meiotic and gametic stages. A combination of mathematical modeling and a survey of empirical studies is used to show that sexually antagonistic zygotic drive is feasible, likely to be widespread in nature, and that it can promote a genetic “arms race” between the homo- and heteromorphic sex chromosomes. This new category of genomic conflict has the potential to strongly influence other fundamental evolutionary processes, such as speciation and the degeneration of the Y and W sex chromosomes. It also fosters a new genetic hypothesis for the evolution of enigmatic fitness-reducing traits like the high frequency of spontaneous abortion, sterility, and homosexuality observed in humans

Raman Spectroscopy of Aged Waterlogged Bones: Protocol Optimization

Current methods used for determining the age buried bones for forensic purposes are heavily affected by environmental conditions, can be susceptible to scientific bias and the interpretation can vary from investigator to investigator. Raman Spectroscopy can potentially be used as an automatic method to analyze the composition of bone eliminating the human factor. To test this hypothesis, we will use Raman spectroscopy to potentially identify the burial time of bones. The change in the chemical composition of the pig bones was probed using a Raman spectrometer with a 785nm excitation wavelength. Other parameters of the Raman instrument were optimized to create a protocol that would be universal for all bone samples, regardless of the age. The best parameters used were 100% laser power, one accumulation, and a 120-second accumulation time. This method was confirmed to be the ideal method for this sample by testing both the youngest and oldest samples in the group. Using this method, the youngest sample was tested in different spots on the particle, and it was seen that there were differences in the spectra, which is another factor that must be accounted for when making the model in the future

Genetic and environmental factors affecting the behavior of ectopic and non-ectopic BXSB mice

BXSB/MpJ inbred mice are as a model of developmental dyslexia in large part because approximately 40–60% have neocortical ectopias, an anomaly also found in dyslexics. Ectopias are caused by migration of neurons into the neuron-sparse layer I of cortex. Previous studies have shown that ectopic BXSB mice have superior reference, but inferior working, memory on spatial tasks; and that environmental enrichment can eliminate some of the differences between ectopic and non-ectopic animals. ^ Chapters 2 and 3 further explore the impact of enrichment, through the use of a water version of the Hebb-Williams maze. Ectopics reared in the standard housing condition were better on mazes that favored the use of reference memory, but worse on mazes that favored working memory; whereas subjects raised in the enriched environment showed no differences. A comparison of enriched and standard housing conditions showed that the enriched animals had deficits in working memory, suggesting that the effects of enrichment enhances reference memory at the expense of working memory. ^ In Chapters 4 and 5, the learning behavior of female offspring of two strains of mice consomic for the Y-chromosome, BXSX/MpJ-Yaa (Yaa) and BXSB/MpJ-Yaa+ (Yaa+), was examined. Sires remained with the litters through weaning. Significant differences were found in the Morris water maze and the Lashley III maze, demonstrating that the Y-chromosome plays a role in the development of female behavior. Furthermore, the Y-chromosomes affected ectopics and non-ectopics differently. Since females do not have a Y-chromosome, this effect must be through non-genetic mechanisms. ^ In the second experiment, sires were removed once conception was verified, and the male siblings were removed at birth. Cognitive differences seen in previous Morris maze studies were eliminated. However, females from sires with different Y-chromosomes differed on several measures of affect. These data suggest that the presence of the sire and/or the male offspring postnatally were important in generating the behavioral differences found previously. These data also suggest that the uterine environment plays an important role in affective behavior. Possible mechanisms of Y-chromosome action within the uterine environment, including growth factors and the presence of H-Y antigen, are discussed.

The uterine environment enhances cognitive competence.

Genetically identical mouse embryos were transferred into same-strain uteri (transfer controls) or into hybrid uteri. A third group was not transferred. When adult, the mice were given a series of behavioral tests. In-strain transfer controls differed from non-transfer mice only on two activity measures, and did not differ on any cognitive variable. In contrast, mice reared in hybrid uteri were found to be superior to in-strain transfer mice on discrimination learning, Lashley maze learning and Morris maze learning; they also showed better adaptation in an avoidance learning shuttlebox. To our knowledge this is the first study showing that the uterine environment can have a general enhancing effect upon cognitive competence across a broad range of behaviors

Effects of the non-pseudoautosomal region of the Y-chromosome on behavior in female offspring of two congenic strains of mice.

The learning behavior of female offspring of two strains of mice congenic for the Y-chromosome, BXSX/MpJ-Yaa and BXSB/MpJ-Yaa+, was examined. Significant differences were found in the Morris water maze and the Lashley III maze, demonstrating that the fathers\u27 Y-chromosome can indirectly affect their daughters\u27 behavior. Approximately half the mice had neocortical ectopias, and females from the two paternal groups reacted differently to the presence or absence of ectopias. Since females do not have a Y-chromosome, these effects must be through non-genetic mechanisms. Prenatal factors that could have played a role include possible differences in gonadal growth and the presence of different H-Y antigens. Postnatally, the sires and male siblings of the two strains may not have behaved the same toward the female offspring and/or the dams, creating differences in behavior.In summary, the behavior of female offspring of two groups of males, genetically the same except for their Y-chromosomes, was examined. Since females do not receive a Y-chromosome from their fathers, in theory their behavior should not differ. Significant differences were found, indicating that the Y-chromosome, through some indirect mechanism, can affect females of the next generation

Effects of ectopias and their cortical location on several measures of learning in BXSB mice.

About half of BXSB/MpJ-Yaa mice have ectopias, which are misplaced clusters of neurons located in layer I of cortex. This study replicated several previous findings showing that there are learning differences between mice with ectopias and those without. In addition, we had sufficient numbers of ectopic mice to investigate if ectopics learned differently depending on the cortical location of the ectopia(s). Mice with at least one ectopia located in prefrontal cortex were initially impaired in learning the Morris maze, as well as relearning the Lashley maze when it was inverted, but learned better in the radial-arm maze when compared to ectopic mice with ectopias located in nonprefrontal regions of cortex. Mice with at least one ectopia in motor cortex learned the Lashley maze better than mice with ectopias located outside motor cortex. In sum, the cortical location of the ectopia(s) affected learning performance in certain tasks within the ectopic group, but regardless of the cortical location of the ectopia(s), ectopics still learned differently than nonectopics in several tasks