Animal & Avian Sciences Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2741
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Item Variations in Vocalizations of Fin Whales, Balaenoptera physalus, in the St. Lawrence River(1980) Edds, Peggy Louise; Buchler, Edward; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Recordings were made of vocalizations from fin whales, Balaenoptera physalus from a fixed hydrophone in the St. Lawrence River between 28 June and 27 September 1979. Land-based observers monitored activity from a hillside hut while recordings were being made from a shoreline site. Photographs of dorsal fin variations were used to identify distinctive individuals. The 1522 sounds recorded were classified into 11 categories based on frequency and temporal characteristics. The predominant call was a descending sweep of frequencies. Parameters measured for this downsweep exhibited a dichotomy of characteristics which indicates calls with initial frequencies below 40 Hz have less variability than calls with initial frequencies above 40 Hz. In general, solitary animals produced primarily the lower frequency downsweeps. Higher frequency downsweeps were recorded from pairs or trios of fin whales. Solitary individuals did not exhibit unique variations in downsweep parameters. No clusters of values which might indicate uniquely individual ranges were consistently present in multiple animal recordings. The data suggest that the variability of fin whale vocalizations is primarily contextual rather than individual.Item Infant and Juvenile-Directed Care Behaviors in Adult Toque Macaques, Macaca Sinica(1985) Baker-Dittus, Anne; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)The identity of care-givers, and the distribution of care to young are examined in a free-ranging polygynous primate, Macaca sinica. Care behavior is used as one measure of investment in young. There is no evidence that dominance rank influences offspring sex, but high-ranking mothers provide more care to newborn infants than do low-ranking mothers. Mothers provide more care to infant and first year sons than to daughters. This supports Dittus's suggestion (1979, 1980) that mothers should schedule care to sons and daughters differently, providing high levels of care to sons before they emigrate from the natal group. Care to daughters is low per unit time, but continues over a long period because daughters remain in the natal group. Adult females, other than the mother, tolerate, groom and support young. These behaviors are low cost, relative to the high cost behaviors of nursing and carrying, which only mothers provide. Young tend to associate with adult female relatives. Unlike male-biased maternal care, adult female care is biased towards female young; and female young return care more than do male young . Adult female rank is positively correlated with the amount of support adult females provide to female young, and the amount of grooming they receive from female young. Adult female rank has no effect on any measure of association between adult females and male young. Taken together these findings suggest that reciprocal altruism has been important in shaping adult female interactions with young. Adult and subadult M. sinica males direct the low cost, affiliative behaviors of hugging, carrying and grooming towards male infants; and direct aggressive behaviors towards female infants. I suggest that the distribution of behaviors reflects their value to male and female young. Affiliative behaviors to male infants, and aggressive behaviors to female infants serve to channel infants into association with adults from whom they can learn appropriate sex-typical behaviors, and as such benefit both male and female infants. High cost care behaviors of support in agonistic interactions, and protection are provided only by the adult male, and are provided to male and female young equally.Item The interaction between a parasitic barnacle, Loxothylacus panopaei (Cirripedia, Rhizocephala), and three of its crab host species (Brachyura, Xanthidae) along the east coast of North America.(1993) Alvarez, Fernando; Reaka-Kudla, Marjorie; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Rhizocephalan barnacles parasitize primarily decapod crustaceans (Bocquet-Vedrine 1968, Overstreet 1983). The principal effect of the parasites is often the permanent sterilization of the hosts (Bocquet-Vedrine 1972, O'Brien & Van Wyk 1984). Regardless of the processes involved, the end result of the infection is the creation of non-reproductive individuals that will use resources that otherwise would be available to the healthy traction of the host population. The potential impact on the host population then resides in the accumulation of sterile resource-using individuals in each generation. Prevalences of barnacles on anomuran and brachyuran crabs have been reported in a number of studies (e.g., Walker 1985, Hawkes et al. 1986, Johnson et al. 1986, Wardle & Tirpak 1991 ). Rhizocephalan infections can reach very high levels locally, suggesting that entire host populations may have a greatly reduced reproductive capacity. However, in most host species, the pattern of distribution of parasites is not uniform throughout the host's range. I examined the crab-rhizocephalan interaction using the system composed by the barnacle Loxothylacus panopaei and three of its crab host species: Panopeus lacustris, Eurypanopeus depressus, and Rhithropanopeus harrisii, occurring along the east coast of the North America. Through experimental infections conducted in the laboratory, it was determined that B. harrisii of a wide range of sizes could be infected by L. panopaei. The complete life-cycle of the parasite was manipulated in the laboratory. Neither host molting frequency nor host molt increments differed significantly between parasitized and control crabs. Host survival was significantly reduced during the parasite's developmental period; the heaviest mortality of the host occurred in the megalopal stage.Item MOLECULAR ANALYSIS OF CYCLOPHILIN FUNCTION IN THE YEAST SACCHAROMYCES CEREVISIAE(1994) Davis, Edward S.; Brennan, Miles S.; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)The cyclophilins are a family of proteins first identified as receptors for cyclosporin A (CsA), a cyclic peptide of fungal origin. CsA inhibits T-lymphocyte activation, and is thus a potent immunosuppressant. Although cyclophilins are ubiquitous, and highly conserved, among eukaryotes, their normal physiological functions are unknown. As the receptors for CsA, cyclophilins might be involved in regulating signal transduction pathways. Cyclophilns also have peptidyl-prolyl, cis-trans isomerase (PPIase) activity in vitro, suggesting a role in protein folding in vivo. While CsA inhibits cyclophilin's PPIase activity, this inhibition is insufficient to account for the pharmacological activity of CsA. Therefore, previous results cannot be readily synthesized into a model for cyclophilin function. The goal of this project was to define and characterize physiological roles of cyclophilins using the yeast S. cerevisiae. Three S. cerevisiae cyclophilin genes were cloned and inactivated by insertional mutagenesis. I demonstrated that one, CPR3, is necessary for the efficient metabolism of non-fermentable carbon sources. The CPR] gene product, Cpr3, is localized to the mitochondrial matrix, and a truncated version of Cpr3 expressed in bacteria binds CsA. CPR3 inactivation does not significantly compromise the induction of transcription of two nuclear cytochrome genes. Thus, Cpr3 is not necessary for the signal transduction pathway governing cytochrome gene expression. To identify biochemical targets of Cpr3, I demonstrated that inactivation of a mitochondrial lactate dehydrogenase is insufficient to account for the growth defect of cpr3 mutants. An exhaustive search for high-copy suppressors of the growth defect of cpr3 mutants led to the identification of a novel gene, JEN1, that suppresses the growth defect at elevated temperature. JEN1 encodes a protein that is probably a lactate transporter, and thus not a direct biochemical target of Cpr3. A dominant mutation in a nuclear gene, JEN2, suppresses the growth defect of cpr3 mutants on lactate at 30°C and 37°C. JEN2 might encode a direct biochemical target of Cpr3. In summary, the cyclophilin, Cpr3, plays a general role in the efficient function of yeast mitochondria, and presents an excellent model system for studying cyclophilin function.Item The Life Cycles, Ecology, and Evolution of the Witch-hazel Leaf Gall Aphid, Hormaphis hamamelidis (Fitch) (Homoptera: Aphidida)(1987) von Dohlen, Carol Dean; Gill, Doulgas E.; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Two divergent life cycles based on geographic location have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis (Fitch, 1851). At low elevations in northern Virginia, the aphid was found to have seven distinct generations alternating between the primary host, Witch-hazel (Hamamelis virginiana L.), and a secondary host, river birch (Betula nigra L.). These findings confirm the original published life cycle description from the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high (1000 m) elevations in north central and northwestern Virginia. Aphids with each life cycle were sympatric at an intermediate elevation site. Based on available life cycle and geographic data, a preliminary Phylogeny of the tribe Hormaphidini is proposed that suggests an unusual polarity in the evolution of aphid life cycles. Several features of intraspecific interactions and host-plant relations were examined in both lowland and highland populations of Hormaphis. In contrast to previous publications documenting severe competition, density effects, and habitat heterogeneity for another galling, host-alternating aphid, Pemphigus betae on Populus angustifolia, the effects of density and host-plant qualities on Hormaphis hamamelidis were fewer and more benign. Aphids did not compete for gall sites, and gall Position and final leaf area did not influence reproduction. High gall densities negatively affected gall growth and aphid fecundity. Factors accounting for the differences in Population dynamics between Hormaphis and Pemphigus are hypothesized and discussed.Item Vertical Resource Partitioning and Sexuality of Three Sympatric Species of Red Sea Sandfishes (Xyrichtys melanopus, Labridae; Trichonotus nikii, Trichonotidae; Gorgasia sp., Congridae)(1988) Krall, Marianne Martha; Clark, Eugenie; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Three species of marine sandfishes were studied from 1984 to 1986. Their inter- and intraspecific behavior was monitored during the daylight hours to examine interactions that could result in the vertical stratification of the species over the sandy bottom within the fringing and patch reefs in the north Red Sea. Horizontal plankton tows were taken at three heights and three times a day. These samples were compared to stomach contents of the fishes to determine the trophic relationships in the community and their affects on spatial relations between the species . Prey specificities of the fishes were determined by using an electivity measure. Using paraffin histology, Xyrichtys melanopus was determined to be a monandric protogynous hermaphrodite and Trichonotus nikii, a gonochorist. Previous work on the mating systems and territoriality of all three sandfish species helped in part to explain the vertical spatial arrangement of the sandfish species within the community. Effects of pollution on the b iota of the Northern Gulf of Aqaba are noted.Item Dietary Control of Cystinuria in Maned Wolves (Chrysocyon Brachyurus)(1998) Boniface, Jennifer; Soares, Joseph H., Jr.; Avian and Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)The maned wolf (Chysocyon brachyurus) is an endangered South American species of canid, whose numbers in both the wild and captivity are threatened in part by a condition called cystinuria. In humans and rats, cystinuria is caused by mutations of the rBAT gene, expressed in intestinal mucosal cells and renal tubules. In dogs, only renal tubules are affected. Cystinuric individuals exhibit impaired capacity for reabsorption of the sulfur amino acid cystine. Consequently, excess cystine accumulates in the urine. In acidic conditions, cystine may precipitate into uroliths, potentially obstructing the urethra and ultimately causing bladder rupture or kidney damage. Treatments include medical management and dietary modification. Test diets differing only in levels of cystine were fed to 15 maned wolves in a cross-over design. Apparent digestibility calculations suggest the diets were well received, well utilized and improved fecal quality. The low cystine diet significantly reduced urinary excretion of cystine (P<0.05). Mean urinary concentrations of cystine were 341±45.87 mg/L or 2.78±0.326% total urinary nitrogen for the low cystine diet; and 475.8± 47.80 mg/L or 4.01± 0.342% for the high cystine diet. Water balance studies was determined three maned wolves, using orally administered deuterium oxide. Urine samples were collected daily for seven days, purified by sublimation, and analyzed by infrared spectrometry. It was determined that total body water, water turnover rate and body composition were 17.2 L, 2.3 L/d, and 20.5% fat; 79.5% lean, respectively. These results are comparable to published values for dogs.Item Investigating Copper Acquisition And Delivery via Transporters and a Pharmacological Chaperone in Copper-Deficient Worms and Mice(2019) Yuan, Sai; Kim, Byung-Eun; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Copper (Cu) is a key micronutrient required for a variety of essential biochemical pathways. Systemic or tissue-specific Cu-deficiencies, caused by insufficient dietary Cu uptake or mutations in Cu transporting genes, result in impaired growth, neuropathy, ataxia, hypopigmentation, osteoporosis and anemia-like symptoms in mammals. How organisms regulate Cu homeostasis at the systemic levels in response to Cu deficiencies remain elusive. In this study, we use Caenorhabditis elegans (C. elegans), a genetically tractable, multi-tissue metazoan to explore Cu homeostasis and investigate these unknowns. The high-affinity Cu transporters encoded by CTR family genes are required for dietary Cu uptake and maintaining systemic Cu balance from yeast to mammals. However, little is known about Cu acquisition mechanisms in C. elegans. We identified ten CTR ortholog genes in C. elegans; of these, chca-1 was functionally characterized. Cu availability regulates transcription of chca-1 in both the intestine and hypodermis, and chca-1 is essential for normal growth, and reproduction in the worm. Additionally, altered Cu balance caused by the loss of CHCA-1 results in defects in Cu-responsive avoidance behavior. Identification of this CTR-like gene in C. elegans, which appears to be essential for normal Cu homeostasis in the worm, illustrates the importance of Cu delivery via CHCA-1 for normal metazoan development and behavioral phenotypes. In addition, we show that a Cu-binding pharmacological chaperone, elesclomol (ES), fully restores the developmental defects and Cu deficiencies in chca-1-depleted worms, as well as the lethality in worms lacking cua-1 expression (Cu exporter ATP7A ortholog), suggesting ES is able to efficiently deliver Cu from dietary sources to peripheral tissues through the intestine in C. elegans. Our study was further expanded to mammalian models such as cardiac-specific Ctr1-depleted (Ctr1hrt/hrt) mice. We found that ES administration fully restores the postnatal lethality, developmental defects and cardiac hypertrophy found in Ctr1hrt/hrt mice, as well as rescuing the secondary systemic Cu homeostasis responses, including aberrant ATP7A protein levels in the liver and intestine. Moreover, ES shows the potential ability to transport Cu across the blood-brain-barrier in in vitro studies. These results illustrate the capability of ES to rescue systemic Cu deficiency in worms and mice, independent of the presence of functional Cu transporters, and shed light on the therapeutic usage of ES in Cu-deficient human diseases.Item Identification of the molecular networks governing ovulation frequency in low and high egg producing turkey hens(2019) Brady, Kristen Marie; Porter, Tom E; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Selection for carcass traits has negatively impacted and varied the reproductive efficiency of the commercial turkey hen, creating overall lowered egg production as well as distinct groups of low egg producing hens (LEPH) and high egg producing hens (HEPH). Ovulation frequency correlates with egg production and differs between LEPH and HEPH. Ovulation is governed primarily by the hypothalamo-pituitary-gonadal (HPG) axis through a preovulatory surge (PS) of luteinizing hormone (LH) and progesterone (P4) but ovulation can be influenced by the hypothalamo-pituitary-thyroid (HPT) axis. Dysregulation of the thyroid and reproductive axes, disrupting the PS, leads to lowered egg production, leaving the poultry industry to compensate with larger breeding flocks. LEPH exhibited hypothalamic and pituitary expression consistent with decreased ovulation stimulation and increased ovulation inhibition as well as decreased steroid synthesis in follicle cells. Neuroendocrine and ovarian tissues from HEPH showed a higher sensitivity and response to in vitro HPG axis stimulation. Moreover, cells from HEPH responded positively to HPG axis inhibition while cells from LEPH responded negatively, indicating functional differences in HPG axis regulation. RNA sequencing results reinforced the higher expression of HPG axis genes in HEPH and showed higher expression of HPT axis genes in LEPH. Estradiol (E2) was identified as an upstream regulator activated in HEPH. Hens with average egg production (AEPH) also showed upregulation of E2 receptors during the PS, suggesting involvement in positive feedback loops. Supporting the role of E2 in neuroendocrine feedback, higher plasma concentrations of E2 were seen during the PS in HEPH. Looking into the HPT axis, LEPH displayed lower plasma concentrations of triiodothyronine (T3) and higher levels of thyroxine (T4) outside of the PS while HEPH displayed lower levels of T3 and higher levels of T4 inside of the PS. The T3 and T4 levels surrounding the PS in HEPH were consistent with levels seen in AEPH. At a molecular, cellular, and endocrine level, the reproductive physiology of LEPH and HEPH differs, ultimately leading to egg production differences. Studies tying the noted differences to egg production rates will allow for identification of genetic markers to increase the reproductive efficiency of commercial breeding hens.Item ANTIBIOTIC ALTERNATIVES FOR TREATMENT OF MASTITIS IN DAIRY CATTLE(2019) Scholte, Cynthia Madeleine; Moyes, Kasey M; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Mastitis is one of the most costly diseases to the dairy cow industry. Implementation of management protocols have decreased the incidence rate of contagious mastitis pathogens, while the incidence of cases caused by environmental pathogens, such as Escherichia coli (E. coli) and Streptococcus uberis (Strep. uberis), remains unchanged. Currently, antibiotics are the primary therapy utilized to control mastitis. However, growing concern for antibiotic overuse, improper use and bacterial resistance have led to the examination of alternative strategies. Two promising alternative mitigation strategies were explored in the research leading to this dissertation. The first is a potent endolysin, PlyC, which has demonstrated bactericidal activity against several streptococcal species in a variety of applications. However, it is unknown how PlyC interacts with the bovine immune system. Varying doses of PlyC were non-toxic and did not alter the oxidative burst response of bovine neutrophils, the first immune cells recruited to the intramammary infection. The second alternative to an antimicrobial drug explored was citrus oil dissolved in ethanol. This was tested against E. coli strain P4. Prior antimicrobial investigations with citrus oil utilized dimethylsulfoxide as a carrier solvent, which is currently prohibited in the dairy industry. Citrus oil and its primary components were tested to determine minimum inhibitory, bactericidal and biofilm eradication concentrations. Citrus oil components, citral and linalool, demonstrated better antimicrobial activity than the native oil in vitro. In addition, citral and linalool were minimally toxic to bovine neutrophils and did not hinder their oxidative burst response in vitro. Because citral demonstrated greater antimicrobial activity than linalool, it was the logical candidate to test for the efficacy as an intramammary therapy against experimentally-induced E. coli mastitis. Unfortunately, citral treatment did not differ from a common intramammary antibiotic therapy or sterile buffered solution. In conclusion, the use of PlyC as an alternative therapy for Strep. uberis mastitis is promising as PlyC may not interfere with immune response during mastitis. The antimicrobial effects of citral may better serve as a disinfectant than a therapy for E. coli mastitis.