• The Status of Crawfish Frogs (lithobates areolatus) in Indiana, and a Tool to Assess Populations

      Engbrecht, Nathan J. (2011-03-16)
      The conservation status of Crawfish Frogs (Lithobates areolatus) in Indiana has changed over the past several decades. Once described as being locally plentiful, declines led to the listing of Crawfish Frogs as a State Endangered Species in 1988. Several records for this species in Indiana are > 50 yrs old and have gone unconfirmed for several decades. However, recent surveys have confirmed the continued presence of Crawfish Frogs in parts of southern Indiana, redefining the perceived range of this species in the state. In an effort to increase survey efficiency in this species, I used automated recording systems and manual call survey techniques to examine the chorusing phenologies of Crawfish Frogs at two sites along the northern extent of their range. Detection probabilities were determined as they related to season and environmental variables and survey duration. I also examined the effect that distance from wetland and position (ground level vs. approximate human ear level) had on call detection in automated recording systems. Correlations between call rates (calls/min) and numbers of male Crawfish Frogs present were used to calculate population estimates at 10 uncensused sites. Detection probabilities were highest when the frogs were breeding and when air temperatures were ≥ 13° C. Initial detection of Crawfish Frogs most frequently occurred during the first five min of sampling. Calls on automated recording units lost resolution as distance from wetland increased, and calls recorded at all distances at human ear level were measurably louder (in decibels) except at the wetland edge. Population estimates at uncensused sites ranged from a low of four to a high of 48. Using call rates and numbers of male frogs present in wetlands, I present a “rapid assessment” tool that can be used to quickly calculate on-site estimates of Crawfish Frogs in field studies.
    • Transgenic Manipulation in Zebra Fish by Combination of Cre-loxP Recombinant System, Tol2 Transposon System, and RNAi Technique

      Bai, Yang (2010-09-21)
      The overall goal of this research is to make precisely controlled transgene constructs to target genes in zebrafish and facilitate their functional studies. Many of the previous transgenic techniques (e.g. morpholino) can only produce transient gene expression or inhibition, which is not good for long-term studies. Also, transgenes that randomly integrate into the chromosomes are typically difficult to control and are poorly regulated. Thus, it would be of great benefit to develop a reversibly controlled transgenic tool to help study gene function. Here, we propose to combine three distinct techniques to generate a stable transgenic tool to facilitate gene functional study in zebrafish, including Cre-loxP recombinant system, Tol2 transposon system, and RNAi technique. The first objective is to combine both Cre-loxP and Tol2 systems to make a convertible and movable transgene construct for insertional inactivation assays in zebrafish. The generated transheterozygous rfp/gfp fragments can be translocated to other loci in the fish genome upon the introduction of Tol2 transposase, which may result in insertional mutations and/or new patterns of interest. The second objective is to make a precisely controlled shRNA transgene construct to inhibit the gfp and/or fli1 expression in zebrafish. Once the target gene is silenced, the zebrafish should show reduced green fluorescence, or some altered phenotypes (in the case of an endogenous blood cell specific target) that can be easily observed. The results showed that we successfully established a stable homozygous pBa/RFP/loxP2/GFP/SBIR transgenic zebrafish line. The conversion from rfp to gfp expression was performed efficiently by heatshock-activated Cre recombinase in vivo. And the subsequent germline transmission of the converted gfp expression was observed in heatshocked pTol-EF1α-RFP-loxP2-GFP transgenic fish outcrosses. The newly generated red/green transheterozygous fish from the cross of non-converted red fish and converted green fish are ready for further insertional mutation assay using Tol2 transgenic fish (Fuji70) or Tol2 mRNA. The construction of the shRNA plasmid was completed and the F0 microinjected zebrafish showed mosaic rfp expression in a few blood vessel cells as well as muscle cells, which indicated the potential success of fli1 driven shGFP transcription in vivo. Future goals include an examination of the efficiency of shGFP anti-gfp expression in pTol-Fli1-EGFP transgenic fish, and Cre recombinase mediated shGFP deletion and target gene expression recovery in vivo.
    • Using MyPlan as a tool for college students in maing their career decisions.

      Lamichhane, Reema (2012-05-21)
      Making a right career choice and preparing accordingly to achieve that career goal is a key to success for every individual. In this study, the researcher evaluated the effectiveness of students using MyPlan, a career assessment tool, to help them make career related decisions. The pretest-posttest analysis showed that MyPlan helped students make an informed career decision to some extent. Chi-squared and correlation analysis of students’ responses before and after taking MyPlan suggested a positive correlation between students taking MyPlan and choosing a college degree major. Also, students agreed strongly when they were asked if MyPlan was helpful in deciding their college major. Collectively, this study derived a strong suggestion that MyPlan is fairly effective and students find it helpful to guide them in making career choices. However, this study was limited as there was a time restraint, subject disparity, and small sample sizes. Therefore, a subsequent study is recommended with a larger sample size and a longer study period. Regardless, this study provided some preliminary data to indicate MyPlan can be an effective tool for college students to guide them in their career decision making process.
    • Using Stable Isotope Analysis to Study Altitudinal and Latitudinal Bat Migration

      Arias, Lily (2014-10-03)
      The general lack of knowledge on basic aspects of the biology of temperate and tropical bats, their low reproductive rates, and threats such as white nose syndrome, wind farms, and habitat loss, make them very susceptible to population declines.My research uses an innovative technique, the analysis of stable isotopes, to study the ecology of bat migration with the main goals of contributing significantly to the understanding of bat biology and assessing the conservation status and susceptibility of bats. In the first chapter,I measured the content of hydrogen isotopes in fur samples of migratory bat species killed at a wind farm in northern Indiana to determine their geographic origin.North American tree bats ( Lasiurus borealis, L. cinereus,and Lasionycteris noctivagans)are considered long distance migrants. In North America, peaks in bat mortality at wind farms occur between mid-July and mid-September. This period is associated with fall migration of bats from their summer (breeding) grounds to their wintering grounds. Thus, wind turbines may have serious negative effects on a strategic event in the life of bats by interrupting migratory connectivity and thereby imperiling the long-term persistence of migratory bat species at large scales.The analysis accurately predicted the known origin of control samples and estimated that non-control bats killed at the wind farm originated from several populations in the United States as well as in Canada. My results highlighted the threat of wind farms to local bat populations as well as to bats originating far from those farms, and emphasized the need for conservation policies across borders.High variation in stable hydrogen isotopes in migrant individuals of all 3 species was observed, suggesting that individuals or populations from a variety of regions pass through the wind farm. In the second chapter,I evaluated the triple-isotopic (hydrogen, carbon, and nitrogen) composition of the tissues of 7 bat species collected at 3 altitudes in the Central Andes of Peru,and the variation of these isotopes across an altitudinal gradient,the application of isotope analysis to migration studies, and trophic effect. Previous studies had demonstrated that iv hydrogen isotopes were a reliable tool to track altitudinal movements of birds, and there was evidence from soil and plant studies that nitrogen and carbon isotopes could serve the same purpose. However, studies focused on bats were lacking. Hydrogen and nitrogen isotopes in the sanguinivorous control were found to be enriched relative to those of the syntopic frugivores.Carbon isotopes in the sanguinivorous bat were depleted when compared to frugivores.Differences in hydrogen found between trophic groups are the first reported for the species studied and support results found elsewhere in the Neotropics.My results demonstrated that, in spite of the wide array of physiological and environmental factors producing temporal and spatial variation, the analysis of hydrogen isotopes is a promising tool to study altitudinal movements of bats when used over long distances. Neither stable isotopes of nitrogen or carbon appear to be reliable to track movements along short gradients such as those along mountains. The contrast of these findings with the results of previous studies suggests that isotopic gradients may be specific to given taxon and localities.My results contributed to the understanding of bat movement patterns and therefore to assessing their sensitivity to potential threats such as habitat loss and connectivity.