Adrenergic and Cholinergic Regulation of Cardiovascular Function in Embryonic Neotropic Cormorants (Phalacrocorax basilianus) (open access)

Adrenergic and Cholinergic Regulation of Cardiovascular Function in Embryonic Neotropic Cormorants (Phalacrocorax basilianus)

Investigations of cholinergic and adrenergic tone on heart rate (fH) and mean arterial pressure (Pm) during embryonic development have been conducted on numerous avian species. While these investigations have documented that adrenergic tone, a continuous stimulation, on fH and Pm is vital to embryonic development in the birds studied to date, development of cholinergic tone on fH has been shown to vary even within species. Further, past studies have been bias to focus primarily on precocial species while altricial species remain poorly understood in this context. The goal of this investigation was to investigate the role of cholinergic and adrenergic tone on fH and Pm of an altricial species, the neotropic cormorant (P. brasilianus) to address this bias. The embryonic neotropic cormorant possesses B-and-a adrenergic tone on fH and Pm at 70% and 90% incubation while cholinergic tone on fH occurs at 90% incubation. This pattern of control is similar to that previously reported for several species of precocial birds suggesting the development of tonic cardiovascular regulation may be conserved across avian taxa.
Date: May 2017
Creator: Cummins, James B.
System: The UNT Digital Library
Development of von Willebrand Factor Zebrafish Mutant Using CRISPR/Cas9 Mediated Genome Editing (open access)

Development of von Willebrand Factor Zebrafish Mutant Using CRISPR/Cas9 Mediated Genome Editing

von Willebrand factor (VWF) protein acts in the intrinsic coagulation pathway by stabilizing FVIII from proteolytic clearance and at the site of injury, by promoting the adhesion and aggregation of platelets to the exposed subendothelial wall. von Willebrand disease (VWD) results from quantitative and qualitative deficiencies in VWF protein. The variability expressivity in phenotype presentations is in partly caused by the action of modifier genes. Zebrafish has been used as hemostasis animal model. However, it has not been used to evaluate VWD. Here, we report the development of a heterozygote VWF mutant zebrafish using the genome editing CRISPR/Cas9 system to screen for modifier genes involved in VWD. We designed CRISPR oligonucleotides and inserted them into pT7-gRNa plasmid. We then prepared VWF gRNA along with the endonuclease Cas9 RNA from Cas9 plasmid. We injected these two RNAs into 1-4 cell-stage zebrafish embryos and induced a mutation in VWF exon 29 of the zebrafish with a mutagenesis rate of 16.6% (3/18 adult fish). Also, we observed a germline transmission with an efficiency rate of 5.5% (1/18 adult fish). We obtained a deletion in exon 29 which should result in truncated VWF protein.
Date: May 2017
Creator: Toffessi Tcheuyap, Vanina
System: The UNT Digital Library
The Effects of Air Pollution on the Intestinal Microbiota: A Novel Approach to Assess How Gut Microbe Interactions with the Environment Affect Human Health (open access)

The Effects of Air Pollution on the Intestinal Microbiota: A Novel Approach to Assess How Gut Microbe Interactions with the Environment Affect Human Health

This thesis investigates how air pollution, both natural and anthropogenic, affects changes in the proximal small intestine and ileum microbiota profile, as well as intestinal barrier integrity, histological changes, and inflammation. APO-E KO mice on a high fat diet were randomly selected to be exposed by whole body inhalation to either wood smoke (WS) or mixed vehicular exhaust (MVE), with filtered air (FA) acting as the control. Intestinal integrity and histology were assessed by observing expression of well- known structural components tight junction proteins (TJPs), matrix metallopeptidase-9 (MMP-9), and gel-forming mucin (MUC2), as well known inflammatory related factors: TNF-α, IL-1β, and toll-like receptor (TLR)-4. Bacterial profiling was done using DNA analysis of microbiota within the ileum, utilizing 16S metagenomics sequencing (Illumina miSeq) technique. Overall results of this experiment suggest that air pollution, both anthropogenic and natural, cause a breach in the intestinal barrier with an increase in inflammatory factors and a decrease in beneficial bacteria. This evidence suggests the possibility of air pollution being a potential causative agent of intestinal disease as well as a possible contributing mechanism for induction of systemic inflammation.
Date: May 2017
Creator: Fitch, Megan N.
System: The UNT Digital Library
Studies on Zebrafish Thrombocyte Function (open access)

Studies on Zebrafish Thrombocyte Function

Thrombocytes are important players in hemostasis. There is still much to be explored regarding the molecular basis of the thrombocyte function. In our previous microarray analysis data, we found IFT122 (an intraflagellar transport protein known to be involved in cilia formation) transcripts in zebrafish thrombocytes. Given recent discoveries of non-ciliary roles for IFTs, we examined the possibility that IFT122 affects thrombocyte function. We studied the role of IFT122 in thrombocyte function. We also found that IFT122 plays a central role in thrombocyte activation initiated by the agonists ADP, collagen, PAR-1 peptide and epinephrine. Although the receptors for ADP, PAR-1 peptide and epinephrine are present in the zebrafish genome, the collagen receptor GPVI was missing. In this study, we identified G6fL as a collagen receptor in zebrafish thrombocytes. Furthermore, IFT knockdown results in reduction in Wnt signaling. The Wnt signaling has been shown to be involved in megakaryocyte proliferation and proplatelets production. Therefore, defects in IFT could lead to thrombocytopenia. Splenectomy is performed in humans to treat such conditions. Therefore, in this study we developed a survival surgery protocol for splenectomy. We have shown that number of thrombocytes and their microparticles increase following splenectomy in zebrafish. Thus overall the studies on …
Date: May 2017
Creator: Pulipakkam Radhakrishnan, Uvaraj
System: The UNT Digital Library