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Full-Text Articles in Life Sciences
Structural Phylogenetics Of A Family Dna Polymerases, Yagmur Bingul
Structural Phylogenetics Of A Family Dna Polymerases, Yagmur Bingul
Honors Theses
The transition from the RNA to the DNA world stands as an important event, demanding the emergence of enzymatic activities for DNA precursor synthesis, retro-transcription of RNA templates, and replication of single and double-stranded DNA molecules. The distribution of protein families associated with these activities across the three domains of life—Archaea, Eukarya, and Bacteria—adds layers of complexity to the narrative. While Archaea and Eukarya often share similar protein structures, structural biology shows homologous, but distinct, structures in Bacteria. On the other hand, viral polymerases emerge as a crucial part of genome replication and transcription. Their versatility, including RNA-dependent RNA polymerase, …
The Diversity And Evolution Of Phenazine Biosynthesis Pathways In Enterobacterales, Christian Leise
The Diversity And Evolution Of Phenazine Biosynthesis Pathways In Enterobacterales, Christian Leise
Honors Theses
Enterobacterales is an order of Gram-negative bacteria that encompasses plant and animal pathogens and organisms of industrial importance. Some of these bacteria produce secondary metabolites classified as phenazines (Phz). Studies in other groups of microorganisms revealed that phenazines are redox-active and exhibit broad antibacterial, antifungal, and antiparasitic activity. Enterobacterales are known to produce phenazines, but details about the diversity, biochemistry, and function of phenazine metabolites in these organisms are missing. In this work, we screened the National Center for Biotechnology Information (NCBI) GenBank for genome sequences of phenazine-producing (Phz+) Enterobacterales. Additionally, genomes of Phz+ strains Pectobacterium carotovorum cc303 and …
Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee
Morphological Variance In Mouthparts And Foraging Behavior In Bumblebees, Ye Jin Lee
Honors Theses
Bumblebees (Hymenoptera: Apidae: Bombus) show an incredible degree of size variation within and between species. Individuals from the same hive may vary up to 10-fold in mass. This variation allows individuals to specialize in foraging on different flowers suited to their morphology. However, as different species have different foraging behaviors, their variation in mouthparts and scaling of mouthparts to body size may have been under different kinds of stabilizing selection as they adapted to collect nectar from flowering plants over evolutionary time. Here, we examined the scaling relationships between body size and mouthpart structures, and the variation in mouthpart shape …
Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray
Patterns Of Genomic Introgression In Topminnow Hybrid Zones, Amanda F. Ray
Honors Theses
Hybridization and introgression are two important evolutionary mechanisms that can increase genetic diversity. Interesting introgression patterns can form when parental species have genes that confer some adaptive benefit to the organism. The Fundulus notatus species complex contains species with various identifying characterisics. Fundulus notatus, the blackstripe topminnow, and Fundulus olivaceus, the blackspotted topminnow, are closely related and occupy many of the same rivers in their preferred niches. These two species often hybridize and form hybrid zones where their niches overlap. We studied two hybrid zones located in the Tombigbee River and Spring River. Within each hybrid zone, we …
A Potential Role Of Evolution In Shaping Modern Human's Behaviors And Morals, Madeleine Sarner
A Potential Role Of Evolution In Shaping Modern Human's Behaviors And Morals, Madeleine Sarner
Honors Theses
Between eight and six million years ago there existed a common ancestor linking the human species with their great ape relatives. Following the arrival of this organism, a lineage of several different human species began to emerge around two to three million years ago in Africa. These species included Homo rudolfensis, Homo habilis, Homo ergaster, Homo erectus, Homo floresiensis, Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens. By analyzing these species and the great ape relatives through literary research, it is possible to begin to investigate the potential role of evolution in constructing modern human behaviors and morals.
The Evolution Of Body Size In The Order Siluriformes, D Cooper Campbell
The Evolution Of Body Size In The Order Siluriformes, D Cooper Campbell
Honors Theses
The evolution of body size has long been a topic of interest to biologists due to the close link between size and various aspects of an organism’s biology. Adult body size is influenced by the underlying tradeoff in energy allocation between maintenance, somatic growth and reproduction. I studied the evolution of a large group of globally distributed (primarily freshwater with some marine forms) fishes to test some basic hypotheses about the evolution of adult body size. Catfish (Siluriformes) are an excellent group for this type of research as they represent approximately 11% of fishes and species range in size from …
Elucidating A Role For Hoxd13 During Gut Development In The Chick And Skate, Elizabeth R. Ackley
Elucidating A Role For Hoxd13 During Gut Development In The Chick And Skate, Elizabeth R. Ackley
Honors Theses
The Hox genes are a family of highly conserved transcription factors that are critical during embryonic development. Although the function of Hox genes is to pattern the embryo from head to tail, the mechanism by which Hox genes do this is unknown. Elucidating the mechanism for Hox gene function can provide insights into how morphologies are formed in a variety of organisms. I am investigating the role of Hoxd13 in patterning the colon in the developing chick. We virally misexpressed the chick ortholog, cHoxd13, in the midgut mesoderm of the chick to validate that transformation to hindgut morphology would occur. …
Evidence Of A Rudimentary Colon In Leucoraja Erinacea, Alyssa M. Simeone
Evidence Of A Rudimentary Colon In Leucoraja Erinacea, Alyssa M. Simeone
Honors Theses
During the transition of animals from water onto land, the colon is believed to have evolved as an essential water-absorbing organ in terrestrial vertebrates to prevent desiccation. The class Chondrichthyes, comprised of sharks, rays, and skates, are isotonic to their marine environment, and thus do not require a functional colon. The Chondrichthyes are an excellent organism for developmental and physiological studies in evolutionary context because they have undergone little evolutionary change since their appearance 450 million years ago. Previous histochemical studies demonstrate potential water absorbing properties in the digestive tract of the little skate, Leucoraja erinacea (Theodosiou et al., 2007). …