The American alligator (Alligator mississippiensis) has been frequently studied in large reservoirs and coastal marshes. Large ontogenetic shifts in their diet and morphology have been linked with changes in habitat use, with adult males using deep, open water and juveniles and nesting females relying on vegetated marsh. In certain regions of the inland portion of the alligator’s range, these different aquatic habitats are represented by seasonal wetlands and riverine systems that are separated by a terrestrial matrix. Ontogenetic habitat shifts, therefore, would require overland movements between systems, which has important implications for conservation of the species. I tested several commonly used methods of surveying alligator populations to determine the most effective method of studying alligators in seasonal wetlands. I then used systematic trapping, nest surveys and radio telemetry to determine habitat use and overland movement rates by different sex and size classes. I found that seasonal wetlands provided nesting and nursery sites for these inland alligator populations, but that both juveniles undergoing an ontogenetic shift and nesting females move between the wetlands and riverine systems. Overland movements by alligators between the wetland and riverine habitats establish a level of functional connectivity between these aquatic ecosystems. I constructed a habitat suitability index of both the wetlands and the surrounding landscape to determine which patch and landscape characteristics were important to wetland use by alligators. I found that both descriptive wetland characteristics and the spatial relationships between wetlands were important predictors of alligator use. Overland movement was related to upland landuse as well as distance between aquatic habitats. Conserving a variety of wetland sizes and types within an intact upland matrix is critical to maintaining connectivity across the landscape. Furthermore, understanding how species may act as mobile links between ecosystems, particularly those with ontogenetic niche shifts, illustrates the importance of approaching conservation from a landscape perspective.

Made available in DSpace on 2015-03-03T11:52:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-21Bitstream added on 2015-03-03T12:06:25Z : No. of bitstreams: 1 000806883_20160721.pdf: 295789 bytes, checksum: 159c50a85925ff03e231c3fde365e2fa (MD5) Bitstreams deleted on 2016-07-25T13:17:38Z: 000806883_20160721.pdf,. Added 1 bitstream(s) on 2016-07-25T13:18:46Z : No. of bitstreams: 1 000806883.pdf: 6972953 bytes, checksum: dc1761ce2f5a60313afee6934ec1da54 (MD5) / Mostramos aqui a ocorrência de poluentes orgânicos persistentes em ovos de jacaré-do-Pantanal (Caiman yacare), coletados em dois municípios do estado de Mato Grosso (Brasil), em 2012 e 2013. p,p’-DDE foi o composto encontrado em maior concentração (51,3 – 78,1 ng g-1 de ovo liofilizado) em ambas as regiões estudadas. Para a extração de pesticidas organoclorados - OCPs - (p,p’-DDD, p,p’-DDE, o,p’-DDT, o,p’-DDD, o,p’-DDE, ?-endosulfan e endosulfan sulfato) e bifenilas policloradas - PCBs - (congêneres 28, 52, 101, 118, 138, 153 e 180), o conteúdo total de ovos de C. yacare, exceto a casca, foi homogeneizado, liofilizado e submetido a um método de extração sólido-líquido com partição em baixa temperatura (ESL-PBT) que previamente foi otimizado e validado. Foi utilizado um cromatógrafo a gás (CG) com detector por captura de elétrons (ECD) para a detecção destes analitos. PCB 209 a 10 ng mL-1 e tetrabromobenzeno (TBB) a 10 ng mL-1 foram utilizados como padrão interno e como padrão de recuperação (surrogate), respectivamente. O método de extração foi otimizado através de um estudo quimiométrico que incluiu um planejamento fatorial 24 com triplicata do ponto central, para determinação das melhores condições de análise dos compostos de interesse. Volume de solvente extrator (8 – 12 mL), tempo de agitação em vortex (1 – 5 min), tempo de centrifugação a 2.500 rpm (5 – 15 min) e tempo de congelamento (4 – 12 h) foram as variáveis consideradas e testadas em dois níveis, mais a triplicata do ponto central. A recuperação normalizada foi utilizada como resposta para avaliação dos fatores que influenciam o método de extração. As respostas normalizadas foram submetidas ao teste t de Student para determinação dos fatores significativos e as interações entre os fatores foram avaliadas a partir da superfície de resposta. O método otimizado inclui 12... / This work shows the occurrence of persistent organic pollutants in the eggs of Caiman yacare, collected in two regions from Pantanal mato-grossense (Brazil), in 2012 and 2013. p,p'-DDE was the analyte found in higher concentration (51.3 - 78.1 ng g-1 of lyophilized egg) in both regions studied. For the extraction of organochlorine pesticides (p,p'-DDD, p,p'-DDE, o,p'-DDT, o,p'-DDD, o,p'-DDE, ?-endosulphan and endosulphan sulfate) and polychlorinated biphenyls - PCBs - (congeners 28, 52, 101, 118, 138, 153, 180) C. yacare eggs, except shell, were homogenized, lyophilized and was applied a method solid-liquid extraction with low temperature partition (SLE-LTP) optimized and validated. A gas chromatograph (GC) with electron capture detector (ECD) was used. PCB 209 10 ng mL-1 was used as internal standard and tetrabromobenzene (TBB) 10 ng mL-1 was used as surrogate. The optimization was based on a chemometric study included a 24 factorial design with three replications of the central point to determine the best conditions for the analysis of compounds of interest. Volume extracting solvent (8-12 mL), vortexing time (1-5 min), centrifugation time at 2,500 rpm (5-15 min) and time freezing (4-12 h) were the variables considered and tested at two levels, plus the triplicate central point. The normalized recovery was used as a response to evaluation of factors that influence the extraction method. The normalized responses were submitted to the Student’s t-test to determine the significant factors and interactions between factors were evaluated from the response surface. The optimized method includes: extractor solvent 12 mL (acetonitrile: ethyl acetate - 6,5:1,5 v/v), 5 min of vortexing time, 15 min centrifugation at 2,500 rpm and 12 hour freezing. To validate the method, The chromatographic area of each analyte relative to the internal standard chromatographic area vs. concentration were used to...

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-06-18T15:07:51Z No. of bitstreams: 1 fernandapereirasilva.pdf: 1453424 bytes, checksum: b2a5a43450827f6489877e9e4ea29cca (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-06-27T11:38:25Z (GMT) No. of bitstreams: 1 fernandapereirasilva.pdf: 1453424 bytes, checksum: b2a5a43450827f6489877e9e4ea29cca (MD5) / Made available in DSpace on 2018-06-27T11:38:25Z (GMT). No. of bitstreams: 1 fernandapereirasilva.pdf: 1453424 bytes, checksum: b2a5a43450827f6489877e9e4ea29cca (MD5) Previous issue date: 2018-02-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A forma e tamanho do corpo são características que diferem entre machos e fêmeas adultos de crocodilianos, entretanto, não existe relato do dimorfismo sexual para filhotes de Melanosuchus niger. O presente estudo teve como objetivo analisar a existência de dimorfismo sexual em filhotes de M. niger com base em dados morfológicos. Os espécimes analisados foram oriundos de um experimento de incubação artificial. Os ovos foram coletados no Lago Tracajá da Reserva de Desenvolvimento Sustentável Mamirauá. As gônadas foram analisadas quanto aos parâmetros macroscópicos (forma, textura, coloração e presença/ausência de ducto de Müller) para verificar se havia dimorfismo sexual. A identificação sexual dos filhotes foi confirmada a partir da análise histológica do complexo-Gônada-Adrenal-Mesonefro (GAM) conforme procedimentos de rotina. Para a análise da variação da forma utilizou-se a morfologia quantificada das placas epidérmicas da cabeça dos filhotes a partir de 13 landmarks submetidos a uma análise de morfometria geométrica. Para isto, foram fotografadas em vista dorsal, a cabeça dos exemplares e utilizados os softwares TPSUtil, TPSDig2 e MorphoJ para análises. A análise histológica serviu para confirmar o sexo dos indivíduos analisados. Foram identificados 38 fêmeas e 12 machos. Nos testículos foi possível observar a presença da túnica albugínea associada a medula pouco diferenciada, onde não foi observada a presença de túbulos seminíferos, apenas a presença de células vacuolizadas. Associado ao mesonefro observou-se a presença de ducto de Müller remanescente. Nos ovários observou-se a presença de um epitélio germinativo evidente, formado por tecido epitelial cuboide simples. Na região medular observou-se a presença de folículos ovarianos e lacunas medulares. O Ducto de Müller apresentou-se ligado ao mesonefro pelo mesossalpinge. Foi observado que as características macroscópicas das gônadas diferem entre os sexos. Os testículos apresentaram um formato elíptico com textura lisa e coloração amarela. Os ovários apresentaram textura granulosa, coloração bege clara e associada a ele observou-se a presença de Ducto de Müller. A análise de componentes principais (PCA) mostrou variação na forma das placas epidérmicas da cabeça de filhotes de M. niger, indicando a presença de dimorfismo sexual. O Componente Principal 1 (PC1) explicou 52,6 % da variação da forma, enquanto o Componente Principal 2 (PC2) explicou 14,4%, e a variação geral explicada por esses dois eixos principais foi de 67,0%. A análise de função discriminante confirmou a presença de dimorfismo sexual (p = 0,01). Foi observado que as fêmeas possuem a região posterior da cabeça mais longa e larga, e a mandíbula mais curta e estreita. Enquanto a região posterior da cabeça dos machos é ligeiramente mais curta e estreita, e a mandíbula mais longa e larga. As características macroscópicas e histológicas das gônadas foram semelhantes às encontradas em outras espécies de crocodilianos. A análise macroscópica demonstrou-se suficiente para identificar o sexo de filhotes de M. niger. Em crocodilianos adultos, o dimorfismo sexual pode estar presente na região do crânio relacionado evolutivamente ao reconhecimento visual do gênero. Entretanto, a seleção sexual não seria tão relevante para os jovens quanto para os indivíduos sexualmente maduros. A variação da forma tanto no crânio quanto na mandíbula encontrada em filhotes de M. niger, sugere que machos e fêmeas possivelmente passaram por diferentes processos ontogênicos. A falta de trabalhos envolvendo o estudo de dimorfismo sexual por meio da técnica de morfometria geométrica em filhotes de outras populações de M. niger e/ou de outras espécies de crocodilianos, dificulta a comparação direta. No entanto, fica claro a importância do estudo de dimorfismo sexual em crias de crocodilianos para estimativa da proporção sexual, principalmente se aplicada em populações naturais. Os modelos morfométricos geométricos podem ajudar a desenvolver representações gráficas do dimorfismo sexual da cabeça nos crocodilianos, o que torna estes resultados importantes para programas de conservação em condições naturais, pois representa uma alternativa não-letal às técnicas utilizadas para identificação sexual em M. niger. / The shape and size of the body are characteristics that differ between adult males and females of crocodilians; however, there is no report about sexual dimorphism for Melanosuchus niger hatchling. The present study had as objective to analyze the existence of sexual dimorphism in of M. niger hatchling based on morphological data. The specimens analyzed in this study came from an artificial incubation experimente. The eggs were collected at Lake Tracajá on Mamirauá Sustainable Development Reserve. The gonads were analyzed with macroscopic parameters (shape, texture, color and presence / absence of Müller duct) to verify if there was sexual dimorphism. The sexual identification of the hatchling was confirmed by the histological analysis of Gonad-Adrenal-Mesonefro (GAM) complex according to routine procedures. For the analysis of the variation of the form the quantified morphology of the epidermal plates of the hatchling' head was used from 13 landmarks submitted to a geometric morphometry analysis. For this, the heads of the specimens were photographed in dorsal view and the TPSUtil, TPSDig2 and MorphoJ software were used for analysis. Histological analysis served to confirm the animal´s sex of this study. There were identified, 38 females and 12 males. In the testes it was possible to observe the presence of the tunica albuginea associated with a little differentiated marrow, where the presence of seminiferous tubules was not observed, only the presence of vacuolated cells. Associated with the mesonephro we observed the presence of the remaining Müller duct. In the ovaries, the presence of an evident germinative epithelium, formed by simple cuboid epithelial tissue was observed. In the medullary region the presence of ovarian follicles and marrow gaps were observed. The Müller Duct was connected to the mesonephro by the mesosalpinge. It was observed that the macroscopic characteristics of the gonads differ between the sexes. They showed elliptical, smoothly, yellow testes. The ovary presents granular structure with light beige coloration and associated with the presence of Müller's Duct. Principal component analysis (PCA) showed variation in the shape of epidermal scales of M. niger hatchling, indicating the presence of sexual dimorphism. The Principal Component 1 (PC1) explained 52.6% of the shape variation, as the Principal Component 2 (PC2) explained for 14.4%, and the overall variation explained by these two main axes was 67.0%. The analysis of discriminant function confirmed the presence of sexual dimorphism (p = 0.01). It was observed that the females have the posterior region of the head longer and wider, and the jaw shorter and narrower. While the posterior region of the males head is slightly shorter and narrower, and the jaw longer and wider. The macroscopic and histological characteristics of the gonads were similar to those found in other species of crocodilians. Macroscopic analysis was sufficient to identify the sex of M. niger hatchling. In adult crocodilians, sexual dimorphism may be present in the region of the skull related evolutionarily to visual recognition of the genus. However, sexual selection would not be as relevant to young people as to sexually mature individuals. The variation of the shape in both the skull and mandible found in M. niger hatchling suggests that males and females may have undergone different ontogenic processes. The lack of work involving the study of sexual dimorphism using a geometric morphometry technique in hatchling of other populations of M. niger and/or other species of crocodilians makes difficult direct comparison. However, it is clear the importance of the study of sexual dimorphism in gilts of crocodilians to estimate the sexual proportion, especially if applied in natural populations. Geometric morphometric models can help to develop graphic representations of sexual dimorphism of the head in crocodilians, which makes these results important for conservation programs under natural conditions, since it represents a non-lethal alternative to the techniques used for sexual identification in M. niger.

abstract: Traumatic injury to the central nervous or musculoskeletal system in traditional amniote models, such as mouse and chicken, is permanent with long-term physiological and functional effects. However, among amniotes, the ability to regrow complex, multi-tissue structures is unique to non-avian reptiles. Structural regeneration is extensively studied in lizards, with most species able to regrow a functional tail. The lizard regenerated tail includes the spinal cord, cartilage, de novo muscle, vasculature, and skin, and unlike mammals, these tissues can be replaced in lizards as adults. These studies focus on the events that occur before and after the tail regrowth phase, identifying conserved mechanisms that enable functional tail regeneration in the green anole lizard, Anolis carolinensis. An examination of coordinated interactions between peripheral nerves, Schwann cells, and skeletal muscle reveal that reformation of the lizard neuromuscular system is dependent upon developmental programs as well as those unique to the adult during late stages of regeneration. On the other hand, transcriptomic analysis of the early injury response identified many immunoregulatory genes that may be essential for inhibiting fibrosis and initiating regenerative programs. Lastly, an anatomical and histological study of regrown alligator tails reveal that regenerative capacity varies between different reptile groups, providing comparative opportunities within amniotes and across vertebrates. In order to identify mechanisms that limit regeneration, these cross-species analyses will be critical. Taken together, these studies serve as a foundation for future experimental work that will reveal the interplay between reparative and regenerative mechanisms in adult amniotes with translational implications for medical therapies. / Dissertation/Thesis / Differentially Expressed Genes in the Early Regenerating Lizard Tail / Gene Ontology of Differentially Expressed Genes in the Early Regenerating Lizard Tail / KEGG and Reactome Pathway Analysis of Differentially Expressed Genes in the Early Regenerating Lizard Tail / 3D Reconstruction of an Alligator Regenerated Endoskeleton / Lateral 2D Serial Sections of a Regenerated Alligator Tail / Doctoral Dissertation Biology 2020

<div>Host-pathogen interactions are the result of long term evolutionary processes due to the conflicting goals of the host and the infections pathogens in their quest for survival, creating an interplay of co-evolution as various adaptation are acquired by one and then in turned adapted to by the other. Selection of the host’s antimicrobial strategies and the resultant adaptations of infectious microorganisms leads to the development of complex and dynamic relationships ranging from symbiotic to commensal to pathogenic. In an effort to understand the selective process and identify unique mechanisms of antimicrobial defense, sera from 18 species (7 invertebrate, 11 vertebrate) were tested for antimicrobial potential against 20 Gram-negative and 11 Gram-positive bacteria. <i>Alligator mississippiensis</i> sera exhibited the strongest inhibitory potential. A transposon mutagenesis screen performed on the resistant bacterium <i>Serratia marcescens</i> identified several genes, including <i>glnL</i>, as necessary for defense. The <i>glnL</i> gene encodes for the sensory histidine kinase/phosphatase NtrB, controlling the expression of regulatory genes in response to nitrogen limitation. Attenuated growth of the Tn::<i>glnL</i> mutant in the presence of alligator serum and minimal media was rescued with nitrogen supplementation, suggesting the existence of a mechanism for nitrogen limitation as an antimicrobial strategy in alligator sera. Utilization of a <i>Drosophila melanogaster</i> oral model of infection showed that <i>glnL</i> is required for <i>S. marcescens</i> virulence, and nitrogen supplementation rescued the phenotype, as measured by fly mortality and bacterial cfu recovery. S. marcescens, an environmentally ubiquitous Gram-negative bacterium, is an opportunistic pathogen in several species, including alligators and Drosophila. Subsequent <i>in vitro</i> testing of the antimicrobial potential of invertebrate hemolymph utilizing the Tn::<i>glnL</i> mutant showed a nitrogen-dependent growth inhibition of species in the order Dipteria. Combined, these results support a model of evolutionary convergence of nitrogen limitation as an antimicrobial mechanism. This work not only identifies a novel antimicrobial strategy that could be used in the development of therapeutics, and a novel virulence factor in <i>S. marcescens</i>, but has broad mplications for bacterial management and can provide insight into the evolutionary history of host-pathogen interactions.</div>

The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality).

Alligator mississippiensis is only distantly related to the other extant alligator (A. sinensis), with much closer relatives known from the geologic past of North America. While A. mississippiensis is well known from the early Pleistocene and later, no Alligator was known from the middle and late Pliocene until the discovery of Haile 7C and 7G late Pliocene (~2 Ma) sites from Florida. These specimens were analyzed using a diagnostic character matrix along with systematic analyses of the results. This research upholds A. mefferdi as a valid taxon, and the utility of the species in fossil identification is further established. The Haile material cannot be placed within either of the aforementioned taxa, and a new species description is planned in a later publication. Furthermore, the systematic analysis used in this research suggests that the line leading to A. sinensis diverged before the earliest known Alligator. An Eocene dispersal of the genus into Asia is plausible.

Research was performed to analyze the performance of the crack, seat, and overlay (CS&O) roadway rehabilitation technique in the Central Coast and Northern regions of California. This technique was evaluated through literature review to determine the state of practice and their conclusions. California highway sections rehabilitated using CS&O were selected for evaluation based on age and location. Pavement distresses and traffic data for these sections were collected and analyzed. Prior to beginning analysis this data was checked for errors, outliers, and omissions. The analysis consisted of checking the data for correlations among distresses and regions. The focus of this research is to develop performance prediction models for pavement distresses in CS&O sections. Using data collected from Caltrans’ Pavement Condition Reporting Software, performance models were developed based on dependent (distress) variables: alligator cracking, transverse cracking, longitudinal cracking, and International Roughness Index (IRI). And independent (explanatory) variables: age, traffic in the form of equivalent single axle load (ESAL), thickness of hot mix asphalt (HMA), thickness of Portland Cement Concrete (PCC), and cumulative traffic in the form of cumulative ESAL. Prediction models were then analyzed for preciseness and sensitivity to the variables included in each model.

No description available.

Extensive use of the organophosphate diazinon has led to its accumulation in aquatic environments and negative effects on fish health. Most studies focus on the effects of short term exposure to high levels of organophosphate pesticides. This research was conducted to assess the effect of chronic sub-lethal exposure to 0, 0.01, and 0.1 mg/L diazinon for 15 and 30 days on blood parameters and histopathological damage in alligator gar, Atractosteus spatula. Fish exposed to either concentration were motionless, produced excess mucous, had lighter skin color, and had skin lesions. Blood indices of red blood cells, leukocytes and hematocrit values significantly decreased but there was no significant change in mean cell volume. Hemoglobin values significantly increased in fish exposed to the low dose for 15 days, but significantly decreased for the other exposure doses and times. On the contrary, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration values significantly increased in fish exposed to both concentrations and duration times. Leukocyte differentials showed significant decreases in lymphocytes with significant increases of monocytes in fish exposed to the high dose in both exposure times. The most frequent biomarker for exposure to organophosphate pesticides is the inhibition of cholinesterase (ChE). Diazinon significantly reduced plasma ChE activity in a dose-dependent manner, with 62% and 72% in the low and high concentrations for 30 days, respectively. Plasma ChE could be determined from peripheral blood samples and did not require sacrifice of the fish. Fish exposed to either diazinon concentration or duration time developed histopathological changes in skin, gills, liver, and kidney tissues. The skin lesions were on the head and body, and progressed into deep ulcerations. The histopathological changes in the liver included hepatic vacuoles, swollen hepatocytes, steatosis, aggregation of macrophages, necrosis, and hepatic fibrosis. Also, exposed fish demonstrated vacuolar degeneration in the hematopoietic tissues of the kidney. Gills showed epithelial hyperplasia in the secondary lamellae. In conclusion, long term exposure to sub-lethal concentrations of diazinon induced significant changes in hematological indices and histopathological alteration in various tissues. Plasma ChE can be used to monitor diazinon exposure in wild gar populations.