Current Search: Lutz, Peter L. (x)
View All Items
(1 - 9 of 9)
- Title
- Altered in vitro immune responses in green turtles (Chelonia mydas) with fibropapillomatosis.
- Creator
- Cray, C., Varela, Rene A., Bossart, Gregory D., Lutz, Peter L., Harbor Branch Oceanographic Institute
- Date Issued
- 2001
- PURL
- http://purl.flvc.org/fau/fd/FA00007242
- Subject Headings
- Green turtle, Chelonia mydas, Papilloma, Immune system
- Format
- Document (PDF)
- Title
- Changes in brain electrical activity (EEG) of the awake freshwater turtle Trachemys scripta elegans during anoxia.
- Creator
- Fernandes, Jacqueline A., Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
There is evidence that suggests that electrical depression might be an important energy saving mechanism during anoxia. This study investigates in more depth the changes in electrographic (EEG) activity of the awake and behaving anoxia-tolerant turtle Trachemys scripta elegans when the turtle was breathing 100% N2. The drastic depression of electrical activity by 75% shown in response to anoxia suggests that electrical depression may be the major contributor to metabolic depression and...
Show moreThere is evidence that suggests that electrical depression might be an important energy saving mechanism during anoxia. This study investigates in more depth the changes in electrographic (EEG) activity of the awake and behaving anoxia-tolerant turtle Trachemys scripta elegans when the turtle was breathing 100% N2. The drastic depression of electrical activity by 75% shown in response to anoxia suggests that electrical depression may be the major contributor to metabolic depression and conservation of energy necessary for survival of long periods of anoxia. However, adaptative response to anoxia does not simply consist of a mere depression of brain activity. In fact, there seems to be a systematic shutting down of some of the electrical components of the brain in a very structured manner during entry to anoxia. These components are associated with the slowing down activity of the brain and thus reducing its energy utilization. The EEG changes accompanying recovery in air were different from the depressive processes of entry into anoxia. Extended slow wave activity during recovery in air is similar to the activity pattern seen in the emergence phase of hibernating mammals. It is likely that there are important parallels between the electrical patterns of anoxia and those of hibernating mammals.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15241
- Subject Headings
- Red-eared slider, Electroencephalography
- Format
- Document (PDF)
- Title
- Effects of various sand types on nest temperature and hatching success in the loggerhead (Caretta caretta) sea turtle.
- Creator
- Cheeks, Rebecca Joan., Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
Because of the logistics involved with field experiments, most of what is known about effects of temperature on the nest environment of loggerhead (Caretta caretta) sea turtles has been learned in the laboratory. Until now, scientists have been forced to speculate on what effects different sands might have on temperature within the nest. Results of the present study indicate that the upper lethal temperature limit of loggerheads is between 33-35C; this temperature is more likely to be reached...
Show moreBecause of the logistics involved with field experiments, most of what is known about effects of temperature on the nest environment of loggerhead (Caretta caretta) sea turtles has been learned in the laboratory. Until now, scientists have been forced to speculate on what effects different sands might have on temperature within the nest. Results of the present study indicate that the upper lethal temperature limit of loggerheads is between 33-35C; this temperature is more likely to be reached in larger clutches, causing high mortality and low emergence success. Furthermore, the metabolic heat of a larger clutch will be exacerbated by warmer sand types. Ranges of temperatures experienced during the middle period of incubation, not only within the clutch, but over the course of the nesting season, are both above and below the pivotal temperature for sex determination in loggerheads. Perhaps it is inappropriate to use mean beach temperatures to predict outcomes of sex ratios on various coasts. It would be more prudent to concern ourselves with predicting survivorship of a clutch using results from this field study along with beach temperatures, rather than using laboratory temperatures to predict sex ratios.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15459
- Subject Headings
- Loggerhead turtle--Nests, Loggerhead turtle--Effect of temperature on
- Format
- Document (PDF)
- Title
- Origin of glutamate release in the normoxic, anoxic and ischemic isolated turtle cerebellum (Trachemys scripta).
- Creator
- Thompson, John William., Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
The uncontrolled release of glutamate is thought to be a key event in the death of the anoxic/ischemic mammalian brain. However the origin of glutamate, vesicular and/or cytoplasmic, is unknown. Likewise, the anoxic turtle releases a surge of glutamate upon anoxic depolarization. Therefore, this study investigated the origin of glutamate release in the isolated cerebellum of the freshwater turtle (Trachemys scripta). The results showed that: during anoxia, low extracellular glutamate levels...
Show moreThe uncontrolled release of glutamate is thought to be a key event in the death of the anoxic/ischemic mammalian brain. However the origin of glutamate, vesicular and/or cytoplasmic, is unknown. Likewise, the anoxic turtle releases a surge of glutamate upon anoxic depolarization. Therefore, this study investigated the origin of glutamate release in the isolated cerebellum of the freshwater turtle (Trachemys scripta). The results showed that: during anoxia, low extracellular glutamate levels are maintained, an ability lost during in vitro ischemia, by a reduction in glutamate release. Upon anoxic depolarization glutamate release originates from the cytoplasm. The lack of vesicular glutamate release is likely the result of an inhibition of vesicular exocytosis. However during in vitro ischemia, the inhibitory signal which blocks vesicular glutamate release during anoxia is lost. This allows a biphasic pattern of glutamate release during ischemia originating initially from vesicular stores which then causes cytoplasmic glutamate release.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12803
- Subject Headings
- Trachemys scripta, Turtles, Cerebral anoxia
- Format
- Document (PDF)
- Title
- The immunology of green turtle fibropapillomatosis.
- Creator
- Varela, Rene A., Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
Green Turtle Fibropapillomatosis has been a disease of intense investigation, with little ascertained as to its cause. This investigation thus delved into the possible link between this disease and immune compromise. This was achieved by creating three groups of animals, one characterized as healthy another as diseased, and a third as recovered. Blood taken from each animal was then applied to the four aspects of our investigation: general chemistry, hematology, specialized chemistry, and in...
Show moreGreen Turtle Fibropapillomatosis has been a disease of intense investigation, with little ascertained as to its cause. This investigation thus delved into the possible link between this disease and immune compromise. This was achieved by creating three groups of animals, one characterized as healthy another as diseased, and a third as recovered. Blood taken from each animal was then applied to the four aspects of our investigation: general chemistry, hematology, specialized chemistry, and in vitro cell proliferation to establish the best diagnostic cues. General chemistry, hematology, and specialized chemistry proved to be inconsequential in elucidating the effects of possible immune compromise. In vitro cell proliferation, though, proved conclusively that t and b like cells were severely depressed in diseased and "recovered" animals, giving conclusive evidence of immune dysfunction in association with fibropapillomatosis.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15518
- Subject Headings
- Green turtle--Diseases, Green turtle--Immunology
- Format
- Document (PDF)
- Title
- The effects of anoxia on protein synthesis and transport in the optic system of the freshwater turtle, Trachemys scripta elegans.
- Creator
- McFadden, Kris Joseph, Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
The effects of anoxia on retinal protein synthesis and axonal transport were investigated in the freshwater turtle, Trachemys scripta. The optic system (retina, optic nerve, optic tract, and optic tectum) of the freshwater turtle was used because, due to its linear structure, it is an ideal model to measure protein production and transport. This species of turtle is known for its ability to withstand long periods of anoxia; however, little data is available on in vivo protein synthesis in the...
Show moreThe effects of anoxia on retinal protein synthesis and axonal transport were investigated in the freshwater turtle, Trachemys scripta. The optic system (retina, optic nerve, optic tract, and optic tectum) of the freshwater turtle was used because, due to its linear structure, it is an ideal model to measure protein production and transport. This species of turtle is known for its ability to withstand long periods of anoxia; however, little data is available on in vivo protein synthesis in the brain on an anoxia-tolerant species. An intraocular injection of S-methionine was used to label retinal proteins during 18 hours of anoxia, and the tissues were removed and prepared for analysis using 2D gel electrophoresis. Using autoradiography the regulation of retinal proteins was compared under normoxic and anoxic conditions. In addition, labeled retinal proteins rapidly transported along the optic nerve and tract, to the tectum were also compared under these conditions. Although certain proteins were produced in lesser amounts during anoxia, the populations of proteins were the same during anoxia as they were in the control, suggesting that all proteins were still produced during anoxia. Additionally, certain proteins were produced in greater amounts during anoxia. The findings suggest that less important proteins are down-regulated in response to anoxia while those proteins that are up-regulated may serve as protective mechanisms that enable the organism to maintain neuronal connections in this system during anoxia.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15509
- Subject Headings
- Turtles--Physiology, Anoxemia, Red-eared slider--Physiology
- Format
- Document (PDF)
- Title
- Long-term stress-induced changes in brain monoamines of the gray snapper, Lutjanus griseus. Neurotransmitters as indicators of physiological stress.
- Creator
- Brager, Darrin H., Florida Atlantic University, Lutz, Peter L.
- Abstract/Description
-
It is well established that altered neurotransmitter levels have long been associated with stress in many mammals. The purpose of this study was to determine if changes in the brain tissue concentration and/or turnover rates of the monoamine neurotransmitters could be used as an early indicator of physiological stress for fish in different aquatic ecosystems. Gray snapper, Lutjanus griseus, were collected from two sites, a pristine (control) and a polluted (experimental) site, classification...
Show moreIt is well established that altered neurotransmitter levels have long been associated with stress in many mammals. The purpose of this study was to determine if changes in the brain tissue concentration and/or turnover rates of the monoamine neurotransmitters could be used as an early indicator of physiological stress for fish in different aquatic ecosystems. Gray snapper, Lutjanus griseus, were collected from two sites, a pristine (control) and a polluted (experimental) site, classification based upon the hydrocarbon content of their sediment. The brains were quickly removed and dissected into three regions: frontal lobes, hypothalamus, and brain stem which were later analyzed for using high performance liquid chromatography. A decrease in brain tissue norepinephrine and dopamine concentration in the frontal lobes and hypothalamus was observed in individuals collected from the polluted site. No significant difference in either norepinephrine or dopamine concentration was present in the brain stem. Despite a decrease in dopamine levels, there was no significant change in dopamine turnover. There was a significant decrease in serotonin concentration in the hypothalamus at the polluted site. There was an increase in serotonergic activity in the hypothalamus and brain stem at the polluted site. A significant decrease in the weight of the hypothalamus in fish from the polluted site was also observed. These results suggest that a change in brain monoamines can be used as a early indicators of chronic environmental stress.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15458
- Subject Headings
- Neurotransmitters, Gray snapper--Effect of stress on, Stress (Physiology)
- Format
- Document (PDF)
- Title
- Ion homeostasis and energy loss in the anoxic frog brain (Rana pipiens).
- Creator
- Knickerbocker, Debra L., Florida Atlantic University, Lutz, Peter L., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
This study investigated the homeostasis of extracellular potassium ion concentration ([K+]e) and correlated energy levels in the anoxic frog brain (Rana pipiens). The results showed K+ ion homeostasis was maintained for 3hrs in anoxia. It confirmed a constant decline in brain ATP in anoxia. It was concluded that ion homeostasis in the frog does not rely on the maintenance of normoxic levels of ATP. When Na+/K+ATPase was inhibited, it was found that initial K+ efflux was decreased in the...
Show moreThis study investigated the homeostasis of extracellular potassium ion concentration ([K+]e) and correlated energy levels in the anoxic frog brain (Rana pipiens). The results showed K+ ion homeostasis was maintained for 3hrs in anoxia. It confirmed a constant decline in brain ATP in anoxia. It was concluded that ion homeostasis in the frog does not rely on the maintenance of normoxic levels of ATP. When Na+/K+ATPase was inhibited, it was found that initial K+ efflux was decreased in the anoxic frog. This could be due to decreased ion permeability in anoxia, an adaptive strategy seen in other anoxic tolerant organisms. However, the study showed once a threshold [K+]e was reached, the final K + efflux pattern was unchanged. This [K+]e appears to represent a membrane potential threshold. Critical energy levels were determined representing the energy minimum to maintain ion homeostasis in the anoxic frog brain.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12717
- Subject Headings
- Northern leopard frog, Cerebral anoxia
- Format
- Document (PDF)
- Title
- A comparison of the ontogeny of energy consumption in leatherback, Dermochelys coriacea and olive ridley, Lepidochelys olivacea sea turtle hatchlings.
- Creator
- Jones, T. Todd, Florida Atlantic University, Lutz, Peter L., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Changes in activity related oxygen consumption and energy partitioning were measured in leatherback and olive ridley sea turtle hatchlings over their first month after nest emergence. Leatherbacks emerge with about 75--90 KJ of energy in the residual yolk at their disposal for growth and movement. In comparison, the residual yolk energy reserves for the olive ridley are estimated to be much less (45 KJ). In leatherbacks resting specific oxygen consumption rates decreased by 53% over the first...
Show moreChanges in activity related oxygen consumption and energy partitioning were measured in leatherback and olive ridley sea turtle hatchlings over their first month after nest emergence. Leatherbacks emerge with about 75--90 KJ of energy in the residual yolk at their disposal for growth and movement. In comparison, the residual yolk energy reserves for the olive ridley are estimated to be much less (45 KJ). In leatherbacks resting specific oxygen consumption rates decreased by 53% over the first post-hatching month (0.0065 ml O2 min-1 g-1--0.0031 ml O2 min-1 g-1), while for ridleys the fall was 32% (0.0038 ml O2 min-1 g-1--0.0026 ml O2 min-1 g-1). Greater differences were seen in aerobic scope. For olive ridleys the factorial aerobic scope doubled over the first month but there was no significant increase in the leatherback's factorial aerobic scope. Leatherback hatchlings gained on average 33% body mass (10 g) over the first week however 70 to 80% of this increase was due to water accumulation. The differences in aerobic scope and energy reserves are related to differences in early life ecological stratagems of these species.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/13139
- Subject Headings
- Sea turtles--Ecology, Animal behavior, Ontogeny, Developmental biology, Adaptation (Physiology), Ecophysiology
- Format
- Document (PDF)
