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Articles 1 - 11 of 11
Full-Text Articles in Life Sciences
Ultrastructural Correlates Of Axons And Synapses Belonging To Different Circuits In Ferret Primary Visual Cortex, Anjelique Sawh
Ultrastructural Correlates Of Axons And Synapses Belonging To Different Circuits In Ferret Primary Visual Cortex, Anjelique Sawh
Dissertations and Theses
The goal of this study was to determine differences in distinctive layers of mammalian primary visual cortex through analysis of their ultrastructural characteristics. Characterizing brain circuitry using 3-dimensional reconstruction of electron microscopy images, and subsequent ultrastructural analysis of axonal populations provides us with a better understanding of the connectivity of the neural circuits. By quantifying ultrastructural differences in axonal processes such as synaptic densities, types of synapses and their post-synaptic densities (PSDs), mitochondrial volumes, synaptic vesicle aggregates, dendritic targets, and bouton volumes, we aimed to understand whether differences in anatomical specializations among different cortical layers could underlie differences in function …
Olfactory Organ Morphology And Ultrastructure Of The Larval Koh Tao Island Caecilian (Ichthyophis Kohtaoensis), Jaclyn M. Patmore
Olfactory Organ Morphology And Ultrastructure Of The Larval Koh Tao Island Caecilian (Ichthyophis Kohtaoensis), Jaclyn M. Patmore
Cal Poly Humboldt theses and projects
The olfactory system of living amphibians (Lissamphibia) undergoes major changes as it transitions from an aquatic to a terrestrial system during metamorphosis. Patterns of change in the cellular morphology of the nose have been examined for frogs (Anura) and salamanders (Caudata). However, it remains unknown if caecilians (Gymnophiona) have similar patterns of change in their nasal ultrastructure. In particular, no data on larval caecilian olfactory cell types are available. Here, using light microscopy and transmission electron microscopy, I examined the olfactory organ of larvae of the caecilian Ichthyophis kohtaoensis, to establish the ultrastructure of the epithelium and compare it …
Characterization Of Hemocytes In Amblyomma Americanum And Investigation Of Traf6’S Role In Proliferation Of Hemocytes In Response To Infection, Jacquelyn T. May
Characterization Of Hemocytes In Amblyomma Americanum And Investigation Of Traf6’S Role In Proliferation Of Hemocytes In Response To Infection, Jacquelyn T. May
Electronic Theses and Dissertations
Amblyomma americanum is a medically important vector in the southeast United States. Cellular and molecular aspects of the immune system of this species were examined. To investigate cellular processes, hemocytes produced in response to gram-negative infection were characterized according to their ultrastructure. Four hemocyte types were identified: prohemocytes, plasmatocytes, type-I granulocytes, and type-II granulocytes. To elucidate molecular processes, we investigated AamTRAF as an immune-related gene by silencing the gene using RNAi then quantifying the hemocytes after inoculation with gram-negative and positive bacteria. It was found that silencing AamTRAF caused a decrease in hemocyte proliferation in response to gram-positive but not …
Comparative Study Of The Effects Of Light On Photophore Ultrastructure From Two Families Of Deep-Sea Decapod Crustaceans: Oplophoridae And Sergestidae, Jamie E. Sickles
Comparative Study Of The Effects Of Light On Photophore Ultrastructure From Two Families Of Deep-Sea Decapod Crustaceans: Oplophoridae And Sergestidae, Jamie E. Sickles
HCNSO Student Theses and Dissertations
Counterillumination, the mechanism by which pelagic species produce bioluminescence to replace the light blocked by their bodies to hide their silhouettes, has been known for over 100 years. However, little is known about how these animals are able to so precisely replicate the intensity of downwelling light. The recent discovery of opsins in photophores (Bracken-Grissom et al. 2020) suggests that these autogenic organs (i.e. non-bacterial) may be sensitive to light, in addition to their function of emitting visible light. The study presented here is 1) the first ultrastructural assessment of photophores in species Systellaspis debilis, Janicella spinicauda, Parasergestes armatus, …
Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson
Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson
Theses and Dissertations
Communication between the male and female gametophyte is vital to successful fertilization during sexual reproduction in plants. One of the proteins known to be important for communication between the male and female gametophyte is LORELEI (LRE). Several studies have shown that there are defects in pollen tube guidance and synergid degeneration, however this is the first study that shows that cell wall thickness in the female gametophyte may also be affected. Previous confocal studies have documented that LRE is present both in the filiform apparatus and found in puncta throughout the cytoplasm. This study confirmed this, but our studies suggest …
Species Specific Microcalcification In Reef Building Caribbean Corals In Ocean Acidification Conditions, Ashley M. Dungan
Species Specific Microcalcification In Reef Building Caribbean Corals In Ocean Acidification Conditions, Ashley M. Dungan
HCNSO Student Theses and Dissertations
Coral reefs are one of the most economically important ecosystems on the planet. Despite their great contribution to the world economy, anthropogenic influence via carbon dioxide emissions is leading to unprecedented changes with concerns about subsequent negative impacts on reefs. Surface ocean pH has dropped 0.1 units in the past century; in spite of this rapid shift in oceanic chemistry, it is unclear if individual species or life stages of Caribbean stony corals will be more sensitive to ocean acidification (OA). Examined is the relationship between CO2-induced seawater acidification, net calcification, photosynthesis, and respiration in three model Caribbean …
Histology And Ultrastructure Of Montastraea Cavernosa And Porites Astreiodes During Regeneration And Recruitment: Anthropogenic Stressors And Transplant Success, Dorothy-Ellen A. Renegar
Histology And Ultrastructure Of Montastraea Cavernosa And Porites Astreiodes During Regeneration And Recruitment: Anthropogenic Stressors And Transplant Success, Dorothy-Ellen A. Renegar
HCNSO Student Theses and Dissertations
Corals combine photosynthesis and calcification in an intricate and delicately balanced relationship to form large biomineralized structures that are dominant features of tropical coastlines worldwide. Coral reefs have great scientific and economic importance but have recently experienced widespread decline attributed to increasing anthropogenic pressure on reef systems. Physical damage events, such as ship groundings, when coupled with existing nutrient stress and changing global climate present a poor outlook for successful natural recovery of reef communities. The main goal of the proposed research is to better understand how environmental factors, both local and global, affect the coral holobiont and influence overall …
The Effect Of Febrile Temperature On Plasmodium Falciparum, Heidi Sue Porter
The Effect Of Febrile Temperature On Plasmodium Falciparum, Heidi Sue Porter
Theses and Dissertations
Previously it has been shown that cultures of Plasmodium falciparum died following exposure to a febrile temperature of 40°C, as demonstrated by a decrease in parasitemia of the following generation. In the current study, the effect of 40°C treatment on culture media, erythrocytes, and parasite glucose consumption, were ruled out as possible influences on parasite death, demonstrating that 40°C impacted the parasites directly. Metabolic profiling of DNA synthesis, protein synthesis, and glucose utilization during exposure to 40°C clearly indicated that febrile temperatures had direct effect on major metabolic pathways and parasite development, beginning 20-24 hr after erythrocyte invasion. The ring …
Ultrastructure Of 'Turbellaria' (Platyhelminthes), Regina Pfistermuller
Ultrastructure Of 'Turbellaria' (Platyhelminthes), Regina Pfistermuller
Electronic Theses and Dissertations
The systematics of turbellarian platyhelminths (also known as free-living flatworms) has proven difficult since few taxonomically useful characters can be discerned in them. Generally, features of the reproductive tract, observed through conventional light microscopy, provide key taxonomic characters. Through the newer techniques of electron microscopy and fluorescence microscopy, new characters are emerging that provide better clues to the phylogenetic relationships of these animals. We have applied both of these microscopies to representatives of two groups of turbellarians whose phylogenetic positions are uncertain and controversial, the Acoela and the Genostomatidae. Because fluorescence microscopy of phalloidin-labeled acoel turbellarians has provided new taxonomically …
An Ulstrastructural Study Of Acetabularia Acetabulum, Rachel Vangilder
An Ulstrastructural Study Of Acetabularia Acetabulum, Rachel Vangilder
Master's Theses
Calcification within the cell and the cell wall Acetabularia acetabulum, a large single cell alga, is examined through an ultrastructural investigation, electron diffraction, and an elemental analysis. These methods suggest that amorphous calcium carbonate is located adjacent to and within the cell wall. The location of the crystals within and directly outside the cell wall suggests the calcium is obtained from the surrounding environment. Fibrillar structures are seen through SEM in areas where calcification is occurring. This fibrillar material appears to serve as the organic matrix where calcification initiates. Intracellularly electron dense materials is seen in the chloroplasts. This …
Ultrastructure Of The Chorionic Villi In The Term Baboon (Papio Sp.) Placenta, Carol Ann Baker
Ultrastructure Of The Chorionic Villi In The Term Baboon (Papio Sp.) Placenta, Carol Ann Baker
Theses & Dissertations
The purpose of this paper is to describe the ultrastructure of the chorion frondosum of the baboon fetal placenta at or near term gestation. There is a void or, at best, only limited ultrastructural information in almost all fields of the biological sciences. The area of placentation is no exception. Since the ultimate goal of many scientific endeavors is the contribution to the vital field of human health, this investigator feels that much information can be gained through the utilization and study of the nonhuman primates in scientific research. The baboon (Papio sp.) has been shown to be quite similar …