Developmental Biology Commons^™

Junctional Actin As A Mechanical Hub For Supracellular Actomyosin Force Transmission During Apical Constriction, Jasneet Brar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Apical constriction is a conserved morphogenetic mechanism that drives epithelial folding during development. During ventral furrow formation in Drosophila melanogaster, contractile actomyosin networks generate forces that reduce apical cell area resulting in tissue invagination. For these cell-scale forces to produce coordinated tissue-scale changes, contractile networks must be mechanically integrated across neighboring cells. Although adherens junctions are known to mediate this coupling, it is unclear how junctions are integrated into cortical actin cytoskeleton, which directly determines cell, and consequently tissue, shape. This thesis tests the hypothesis that supracellular actomyosin organization during apical constriction depends on distinct adherens junction based mechanical couplings: …

Regulation Of Embryonic Eye Regrowth In Xenopus Laevis, Dylan Guerin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Regrowth of lost organs and tissues is an amazing ability that some animals possess. For regrowth to be considered full, the organism must regrow the organ or tissue to a state that is structurally and functionally similar to that which was lost. The ability of an organism to regrow lost or damaged tissue varies among animals, both in the mechanisms utilized to achieve regrowth, and in what body parts can be regrown. Potentially even closely related species can vary wildly in regenerative ability. Therefore, regenerative research can look to other tissues and organisms for direction in elucidating the mechanisms through …

Mob Family Proteins And Tricornered Kinase Are Required To Form Dorsal Appendages Of The Drosophila Eggshell, Keala H. D. Watson

UNLV Theses, Dissertations, Professional Papers, and Capstones

To understand how complex tissues are formed, we need to understand how cells communicate with other cells to build structures. In Drosophila melanogaster, epithelial cells form tubular structures to shape the dorsal appendages on the eggshells. One signaling pathway needed for this event is the Hippo-like kinase intracellular pathway. I focus on two key components in this pathway: the NDR kinase Tricornered (Trc) and Mob proteins. In eukaryotes, Mob proteins are known to interact with NDR kinases to promote their activation. The Hippo- like pathway involves the NDR kinase Trc; however, the specific Mob protein(s) that interact with Trc …

Investigating Conserved Mechanisms For Embryonic Eye Regrowth In Xenopus Laevis, Cindy Kha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Regeneration is a complex process to replace or restore tissue after damage. However, animals vary in their ability to regenerate tissue, and humans are limited in their abilities. Understanding how regeneration occurs in highly regenerative vertebrates, such as in Xenopus laevis frogs will lead to defining common regeneration mechanisms. In recent years, eye regeneration research in Xenopus laevis tadpoles provided new promising insight into the mechanisms necessary for repair of damaged eye tissue. Much progress has been made towards understanding the regenerative capability of the complex eye since Xenopus tadpoles can regenerate mature eye tissues, including: the optic nerve, retina, …

Impacts Of Motor Developmental Delay On The Inter-Joint Coordination Using Kinematic Synergies Of Joint Angles During Infant Crawling, Li Zhang, Chun F. Deng, Yuan Liu, Lin Chen, Naong Xiao, Sheng J. Zhai, Wen S. Hou, Yu X. Chen, Xiao Y. Wu

Electrical & Computer Engineering Faculty Research

Motor developmental delay (MDD) usually affects the inter-joint coordination for limb movement. However, the mechanism between the abnormal inter-joint coordination and MDD is still unclear, which poses a challenge for clinical diagnosis and motor rehabilitation of MDD in infant’s early life. This study aimed to explore whether the joint activities of limbs during infant crawling are represented with kinematic synergies of joint angles, and evaluate the impacts of MDD on the inter-joint coordination using those synergies. 20 typically developing infants, 16 infants at risk of developmental delay, 11 infants at high risk of developmental delay and 13 infants with confirmed …

Bone Morphogenetic Protein Signaling Requirement In Centripetal Migration In Drosophila Melanogaster Oogenesis, Sheila Mosallaei

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cells interact with each other via signals to coordinate migration for proper tissue development and maintenance, immunity and tissue repair. Signals regulate migration via changes to cytoskeletal components or transcriptional regulation. Here, I used Drosophila melanogaster to investigate whether and how a transcriptional signal, Bone Morphogenetic Protein signaling, drives a cell migration, centripetal migration. The migrating cells, centripetal follicle cells, consist of two subsets of cells, “leading” and “following” centripetal follicle cells, that although adjacent to each other, migrate differently. The differences in modes of migration correlate to differential gene expression in the centripetal follicle cells. The leading centripetal follicle …

Flame Retardants And Neurodevelopment: An Updated Review Of Epidemiological Literature, Ann M. Vuong, Kimberly Yolton, Kim M. Cecil, Joseph M. Braun, Bruce P. Lanphear, Aimin Chen

School of Public Health Faculty Research

Purpose of Review: Flame retardant (FR) compounds can adversely impact neurodevelopment. This updated literature review summarizes epidemiological studies of FRs and neurotoxicity published since 2015, covering historical (polybrominated biphenyls [PBBs], polychlorinated biphenyls [PCBs]), contemporary (polybrominated diphenyl ethers [PBDEs], hexabromocyclododecane [HBCD], and tetrabromobisphenol A [TBBPA]), and current-use organophosphate FRs (OPFRs) and brominated FRs (2-ethylhexyl 2,3,4,5-tetrabromobezoate [EH-TBB] TBB), bis(2-ethylhexyl) tetrabromophthalate [BEH-TEBP]), focusing on prenatal and postnatal periods of exposure. Recent Findings: Continuing studies on PCBs still reveal adverse associations with child cognition and behavior. Recent studies indicate PBDEs are neurotoxic, particularly for gestational exposures with decreased cognition and increased externalizing behaviors. Findings …

Analysis Of Spheno-Occipital Synchondrosis (Sos) Fusion In A Contemporary Southern Nevada Subadult Hispanic Population Using Archival Cone-Beam Computerized Tomography (Cbct) Images, Megan Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study employs the three-dimensional visualization capability of cone-beam computed tomography (CBCT) to investigate the relationship between chronological age and timing of fusion of the spheno-occipital synchondrosis in a male/female subadult Hispanic population of Southern Nevada. The sample includes cross-sectional data of 374 orthodontic patients (166 males and 208 females) aged 8-20 years. The SOS is scored by a four-stage scoring system as completely open (stage 0), less than half fused (stage 1), more than half fused (stage 2), or completely fused (stage 3) as visualized in the midsagittal plane in the CBCT image. The relationship between SOS fusion stage …

Delineation Of Events In Centripetal Migration During Drosophila Oogenesis, Travis Tait Parsons

UNLV Theses, Dissertations, Professional Papers, and Capstones

All multicellular organisms initially start out as a single cell. This cell must use the genetic information encoded in its DNA to multiply in number and build itself into a complex multicellular organism. How this process occurs is the focus of developmental biology, a field that seeks to understand how a combination of genetic information and environmental conditions shape a cell from its beginnings as a zygote all the way to maturity. A fundamental part of this process is the ability of cells to work together in order to build complex tissues and organs. Cells achieve this coordination by using …

Mob-Ndr Kinase Signaling Components Are Required For Epithelial Tube Formation In The Drosophila Follicular Epithelium, Juan Carlos Duhart

UNLV Theses, Dissertations, Professional Papers, and Capstones

A major goal of developmental biology is to understand how a single fertilized cell can give rise to the many functional tissues and organs, of specific sizes and shapes, that make up the adult body plan. Over the last 25 years, developmental geneticists have uncovered much concerning the cell-to-cell communication systems that are necessary to build complex tissues and organs. For example, throughout development, cells communicate with their neighbors using specialized signaling molecules. These signals are instructive and provide “signal-receiving” cells with information about space and time. That is, signal-receiving cells “learn” precisely where they are located, and, how far …

Effect Of Larval Starvation On Lipid Content Of Drosophila Melanogaster Over 15 Days, Fabian Leija, Allen Gibbs

LSAMP Poster Presentations

Starvation-resistant Drosophila melanogaster, common fruit flies, deriving from 121 generations of starvation selection, have resulted in genetically, behaviorally, and physiologically different individuals compared to non-resistant counterparts. Starvation-resistant Drosophila are more obese, containing twice as much lipids as control flies.This is a result of starvation-resistant fly larva feeding for 5 days and then entering the pupa stage while non-resistant flies only feed for 4 days.

In this experiment, we hope to answer the question of whether the starvation-resistant flies are genetically predisposed to be substantially more obese than wild populations or if it is a result of this alternate behavior …

Eye Repair In Xenopus Laevis, Cindy Xuan-Mai Kha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Eye development in vertebrates of complex steps that include specific interactions of the neuroectoderm and overlying head ectoderm. The African clawed frog, Xenopus laevis (X. laevis), has a well-characterize eye developmental pathway and is an established model for eye regeneration research. Additionally, Xenopus frogs have high regenerative abilities to regenerate individual eye tissues such as the retina, lens, and cornea. However, it was previously shown that the removal of the specified eye field during the neurulation stage or an eye during the swimming tadpole stage does not permit an eye to regenerate. Here we will describe a model for investigating …

The Grass Shrimp, Palaemonetes, Pugio: Hypoxic Influences On Embryonic Development, Christensen C. Javier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Grass shrimp,Palaemonetes pugio, can survive in brackish waters and estuarine ecosystems despite the frequent oscillations and fluctuations in salinity, temperature and oxygen. AdultP. pugiohave the ability to osmoregulate (Romney and Reiber 2011), change cardiac parameters to tolerate temperatures (not yet published, Mika and Reiber) and oxyregulate (Guadagnoli and Reiber 2013). Manipulation of cardiac parameters allows for these methods of regulation. However, cardiac contraction and internal convection of oxygen do not occur until later stages of embryonic development. Studies focused on these morphological and physiological advantages may provide further understanding of the regulatory mechanisms within grass shrimp embryos, larvae and adults. …

Embryonic Development Of The Grass Shrimp, Palaemonetes Pugio, And The Influence Of Salinity On Cardiac Physiology, Amie Lynn Romney

UNLV Theses, Dissertations, Professional Papers, and Capstones

The grass shrimp, Palaemonetes pugio, inhabit the brackish waters along the Atlantic coast of North America and are a key component of the estuarine ecosystem. These decapod shrimp can tolerate large fluctuations in environmental parameters including daily and seasonal fluctuations in salinity between 0 to 55 parts per thousand (seawater at 30-32 ppt). Any observed distribution patterns of adult P. pugio in relation to salinity may be accounted for by their relative ability to tolerate a range in salinity and their ability to maintain internal water volumes and cardiac performance in the earliest life stage, the embryonic period. This thesis …