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Sample records for alligator cyp3a77 gene

  1. Up-regulation of the alligator CYP3A77 gene by toxaphene and dexamethasone and its short term effect on plasma testosterone concentrations.

    PubMed

    Gunderson, M P; Kohno, S; Blumberg, B; Iguchi, T; Guillette, L J

    2006-06-30

    In this study we describe an alligator hepatic CYP3A gene, CYP3A77, which is inducible by dexamethasone and toxaphene. CYP3A plays a broad role in biotransforming both exogenous compounds and endogenous hormones such as testosterone and estradiol. Alligators collected from sites in Florida that are contaminated with organochlorine compounds exhibit differences in sex steroid concentrations. Many organochlorine compounds induce CYP3A expression in other vertebrates; hence, CYP3A induction by organochlorine contaminants could increase biotransformation and clearance of sex steroids by CYP3A and provide a plausible mechanism for the lowering of endogenous sex steroid concentrations in alligator plasma. We used real time PCR to examine whether known and suspected CYP3A inducers (dexamethasone, metyrapone, rifampicin, and toxaphene) up-regulate steady state levels of hepatic CYP3A77 transcript to determine if induction patterns in female juvenile alligators are similar to those reported in other vertebrates and whether toxaphene, an organochlorine compound found in high concentrations in Lake Apopka alligators, induces this gene. Estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), androgen receptor (AR), glucocorticoid receptor (GR), progesterone receptor (PR), and steroid-xenobiotic receptor (SXR) transcripts were also measured to determine whether any of these nuclear receptors are also regulated by these compounds in alligators. Dexamethasone (4.2-fold) and toxaphene (3.5-fold) significantly induced CYP3A77 gene transcript, whereas rifampicin (2.8-fold) and metyrapone (2.1-fold) up-regulated ERbeta after 24h. None of the compounds significantly up-regulated AR, ERalpha, GR, PR, or SXR over this time period. Plasma testosterone (T) did not change significantly after 24h in alligators from any of the treatment groups. Dexamethasone treated animals exhibited a strong relationship between the 24h plasma T concentrations and CYP3A77 (R(2)=0.9, positive

  2. Gene expression patterns in juvenile American alligators (Alligator mississippiensis) exposed to environmental contaminants.

    PubMed

    Kohno, Satomi; Bermudez, Dieldrich S; Katsu, Yoshinao; Iguchi, Taisen; Guillette, Louis J

    2008-06-23

    Reproductive and developmental abnormalities have been reported in the American alligator (Alligator mississippiensis) population from Lake Apopka, FL, that is chronically exposed to a complex mixture of environmental contaminants. To begin to understand the molecular mechanisms that could lead to the observed abnormalities of the reproductive and endocrine system, we quantified concentrations of the steroid hormones testosterone (T) and estradiol-17beta (E(2)) and expression of steroid hormone receptors and genes relating to steroidogenesis in gonadal tissue from juvenile alligators from three lakes in Florida using enzyme immunoassay and quantitative real-time polymerase chain reaction. Alterations of ESR2 (estrogen receptor beta) and SF1 (steroidogenic factor 1) mRNA expression in male gonadal tissue, without an observed difference in plasma concentrations of T, from the different lakes, begin to provide insight into potential mechanisms underlying the alterations of the reproductive system previously observed. Likewise, alterations in P450 aromatase and DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia congenita critical region on the X chromosome, gene 1) mRNA expression, with elevated plasma E(2) concentrations in females, provide leads to the potential mechanisms modifying folliculogenesis and ovarian development. The investigation of these genes also helps clarify normal endocrine and reproductive system function in the American alligator.

  3. Sex-biased expression of sex-differentiating genes FOXL2 and FGF9 in American alligators, Alligator mississippiensis

    PubMed Central

    Janes, Daniel E.; Elsey, Ruth M.; Langan, Esther M.; Valenzuela, Nicole; Edwards, Scott V.

    2013-01-01

    Across amniotes, sex-determining mechanisms exhibit great variation yet the genes that govern sexual differentiation are largely conserved. Studies of evolution of sex-determining and sex-differentiating genes require an exhaustive characterization of functions of those genes such as FOXL2 and FGF9. FOXL2 is associated with ovarian development and FGF9 is known to play a role in testicular organogenesis in mammals and other amniotes. As a step toward characterization of the evolutionary history of sexual development, we measured expression of FOXL2 and FGF9 across three developmental stages and eight juvenile tissue types in male and female American alligators, Alligator mississippiensis. We report surprisingly high expression of FOXL2 before the stage of embryonic development when sex is determined in response to temperature and sustained and variable expression of FGF9 in juvenile male but not female tissue types. Novel characterization of gene expression in reptiles with temperature-dependent sex determination such as American alligators may inform the evolution of sex-determining and sex-differentiating gene networks as they suggest alternative functions from which the genes may have been exapted. Future functional profiling of sex-differentiating genes should similarly follow other genes and other species to enable a broad comparison across sex-determining mechanisms. PMID:23689672

  4. Sex-biased expression of sex-differentiating genes FOXL2 and FGF9 in American alligators, alligator Mississippiensis.

    PubMed

    Janes, D E; Elsey, R M; Langan, E M; Valenzuela, N; Edwards, S V

    2013-01-01

    Across amniotes, sex-determining mechanisms exhibit great variation, yet the genes that govern sexual differentiation are largely conserved. Studies of evolution of sex-determining and sex-differentiating genes require an exhaustive characterization of functions of those genes such as FOXL2 and FGF9. FOXL2 is associated with ovarian development, and FGF9 is known to play a role in testicular organogenesis in mammals and other amniotes. As a step toward characterization of the evolutionary history of sexual development, we measured expression of FOXL2 and FGF9 across 3 developmental stages and 8 juvenile tissue types in male and female American alligators, Alligator mississippiensis. We report surprisingly high expression of FOXL2 before the stage of embryonic development when sex is determined in response to temperature, and sustained and variable expression of FGF9 in juvenile male, but not female tissue types. Novel characterization of gene expression in reptiles with temperature-dependent sex determination such as American alligators may inform the evolution of sex-determining and sex-differentiating gene networks, as they suggest alternative functions from which the genes may have been exapted. Future functional profiling of sex-differentiating genes should similarly follow other genes and other species to enable a broad comparison across sex-determining mechanisms. Copyright © 2013 S. Karger AG, Basel.

  5. Increased posthatching mortality and loss of sexually dimorphic gene expression in alligators (Alligator mississippiensis) from a contaminated environment.

    PubMed

    Milnes, Matthew R; Bryan, Teresa A; Katsu, Yoshinao; Kohno, Satomi; Moore, Brandon C; Iguchi, Taisen; Guillette, Louis J

    2008-05-01

    A previous study from our laboratory examining development in neonatal alligators from polluted Lake Apopka, Florida, found numerous differences relative to neonates from a reference site, Lake Woodruff National Wildlife Refuge. We postulated that the differences were the result of organizational changes derived from embryonic exposure to environmental contaminants and are related to the poor reproductive success reported in alligators from Lake Apopka. In this study we examine differences in alligators collected as eggs from these two populations and raised under similar conditions for 1 yr. Egg hatch rates did not differ between lake populations; however, posthatching mortality was much higher among Lake Apopka hatchlings. Snout-vent length and body mass were greater in Lake Apopka hatchlings, but no differences were detected between lake populations in thyroid, liver, and spleen mass corrected for body size or in plasma concentrations of testosterone and estradiol. Males from Lake Woodruff exhibited greater relative expression of gonadal mRNA for steroidogenic factor 1 (Nr5a1) and steroidogenic acute regulatory protein (Star) than males from Lake Apopka. Alligators from Lake Woodruff also expressed all genes examined in a sexually dimorphic pattern. In contrast, mRNA expression did not differ between males and females from Lake Apopka for Nr5a1, Star, cytochrome P450 11A1 (Cyp11a1), and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (Hsd3b1). Our results document persistent differences in development, survivorship, and gene expression in alligators from a contaminated environment. Because these animals were raised under similar laboratory conditions, the differences are most likely of embryonic origin and organizational in nature.

  6. Molecular cloning of ESR2 and gene expression analysis of ESR1 and ESR2 in the pituitary gland of the Chinese alligator (Alligator sinensis) during female reproductive cycle.

    PubMed

    Zhang, Ruidong; Yin, Yanan; Sun, Long; Yan, Peng; Zhou, Yongkang; Wu, Rong; Wu, Xiaobing

    2017-08-05

    Estrogens play critical roles in reproductive physiology via estrogen receptors (ESRs) in vertebrates, including reptiles. Chinese alligator (Alligator sinensis) is an endemic and endangered reptile species in China. In the present study, we cloned ESR2 gene from the ovary using rapid amplification of cDNA ends (RACE), investigated the spatial expression of ESRs in various tissues and temporal expression of ESRs in the pituitary glands during the reproductive cycle in Chinese alligators by quantitative real-time PCR (qPCR). Bioinformatics and phylogenetic analysis of deduced ESR2 protein were also performed. The full-length cDNA of the ESR2 is 1647bp in length, with an open-reading frame encoding 548 amino acids. The bioinformatics analysis indicated that the deduced amino acid sequence of alligator ESR2 was highly conserved with that of other vertebrate species. In addition, compared to human ESR2, the 14 amino acids in the alligator ESR2 that are essential for specific recognition of estradiol are entirely conserved. The phylogenetic analysis showed that alligators were more closely related to birds than to other reptiles. The results of qPCR showed that the tissue distribution patterns of both ESR subtype mRNAs appeared to be different. In male tissues, the highest mRNA level of both ESRs is in the liver. While in female tissues, ESR1 and ESR2 showed the highest mRNA level in the hypothalamus and pituitary gland, respectively. During the female reproductive cycle, the expression level of ESR1 mRNA increased from the initial post-hibernation period to the reproductive period, reached its peak in the reproductive period, and then decreased in the autumn active period and hibernation period. Conversely, the highest transcription level of ESR2 was observed in the hibernation period. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A Comprehensive Analysis of the Phylogeny, Genomic Organization and Expression of Immunoglobulin Light Chain Genes in Alligator sinensis, an Endangered Reptile Species

    PubMed Central

    Lu, Yan; Zhang, Chenglin; Wu, Xiaobing; Han, Haitang; Zhao, Yaofeng; Ren, Liming

    2016-01-01

    Crocodilians are evolutionarily distinct reptiles that are distantly related to lizards and are thought to be the closest relatives of birds. Compared with birds and mammals, few studies have investigated the Ig light chain of crocodilians. Here, employing an Alligator sinensis genomic bacterial artificial chromosome (BAC) library and available genome data, we characterized the genomic organization of the Alligator sinensis IgL gene loci. The Alligator sinensis has two IgL isotypes, λ and κ, the same as Anolis carolinensis. The Igλ locus contains 6 Cλ genes, each preceded by a Jλ gene, and 86 potentially functional Vλ genes upstream of (Jλ-Cλ)n. The Igκ locus contains a single Cκ gene, 6 Jκs and 62 functional Vκs. All VL genes are classified into a total of 31 families: 19 Vλ families and 12 Vκ families. Based on an analysis of the chromosomal location of the light chain genes among mammals, birds, lizards and frogs, the data further confirm that there are two IgL isotypes in the Alligator sinensis: Igλ and Igκ. By analyzing the cloned Igλ/κ cDNA, we identified a biased usage pattern of V families in the expressed Vλ and Vκ. An analysis of the junctions of the recombined VJ revealed the presence of N and P nucleotides in both expressed λ and κ sequences. Phylogenetic analysis of the V genes revealed V families shared by mammals, birds, reptiles and Xenopus, suggesting that these conserved V families are orthologous and have been retained during the evolution of IgL. Our data suggest that the Alligator sinensis IgL gene repertoire is highly diverse and complex and provide insight into immunoglobulin gene evolution in vertebrates. PMID:26901135

  8. A Comprehensive Analysis of the Phylogeny, Genomic Organization and Expression of Immunoglobulin Light Chain Genes in Alligator sinensis, an Endangered Reptile Species.

    PubMed

    Wang, Xifeng; Cheng, Gang; Lu, Yan; Zhang, Chenglin; Wu, Xiaobing; Han, Haitang; Zhao, Yaofeng; Ren, Liming

    2016-01-01

    Crocodilians are evolutionarily distinct reptiles that are distantly related to lizards and are thought to be the closest relatives of birds. Compared with birds and mammals, few studies have investigated the Ig light chain of crocodilians. Here, employing an Alligator sinensis genomic bacterial artificial chromosome (BAC) library and available genome data, we characterized the genomic organization of the Alligator sinensis IgL gene loci. The Alligator sinensis has two IgL isotypes, λ and κ, the same as Anolis carolinensis. The Igλ locus contains 6 Cλ genes, each preceded by a Jλ gene, and 86 potentially functional Vλ genes upstream of (Jλ-Cλ)n. The Igκ locus contains a single Cκ gene, 6 Jκs and 62 functional Vκs. All VL genes are classified into a total of 31 families: 19 Vλ families and 12 Vκ families. Based on an analysis of the chromosomal location of the light chain genes among mammals, birds, lizards and frogs, the data further confirm that there are two IgL isotypes in the Alligator sinensis: Igλ and Igκ. By analyzing the cloned Igλ/κ cDNA, we identified a biased usage pattern of V families in the expressed Vλ and Vκ. An analysis of the junctions of the recombined VJ revealed the presence of N and P nucleotides in both expressed λ and κ sequences. Phylogenetic analysis of the V genes revealed V families shared by mammals, birds, reptiles and Xenopus, suggesting that these conserved V families are orthologous and have been retained during the evolution of IgL. Our data suggest that the Alligator sinensis IgL gene repertoire is highly diverse and complex and provide insight into immunoglobulin gene evolution in vertebrates.

  9. Lymphoid follicular cloacal inflammation associated with a novel herpesvirus in juvenile alligators (Alligator mississippiensis).

    PubMed

    Govett, Pamela D; Harms, Craig A; Johnson, April J; Latimer, Kenneth S; Wellehan, James F X; Fatzinger, Michael H; Christian, L Shane; Kelly, Terra R; Lewbart, Gregory A

    2005-09-01

    Multifocal hyperemic nodules and plaques associated with the cloacal mucosa of juvenile alligators (Alligator mississippiensis) at a public aquarium were investigated. Grossly, pale pink to dark red multifocal, circular lesions of varying degrees of severity were identified on the cloacal and, in males, phallus mucosa. Cloacal mucosa biopsies were obtained from 2 of the alligators. These samples were examined histologically and by polymerase chain reaction (PCR) using consensus primers targeting a conserved region of the herpesvirus polymerase gene. Microscopically, the lesions were characterized as submucosal lymphoid follicles with hyperemia and hemorrhage. No inclusion bodies were observed. Minimal to no anisokaryosis was present, and no etiologic agents were identified. Through PCR, a band consistent in size with herpesvirus was observed. Tissues showing similar clinical, histopathologic, and PCR findings were collected from animals at an alligator farm several months later. Sequencing of the PCR amplicon resulted in a 180-base pair sequence that shared 85% sequence identity with tortoise herpesvirus-1.

  10. Alligator, Alligator mississippiensis, habitat suitability index model

    USGS Publications Warehouse

    Waddle, Hardin

    2017-01-01

    The 2012 Coastal Master Plan utilized Habitat Suitability Indices (HSIs) to evaluate potential project effects on wildlife species. Even though HSIs quantify habitat condition, which may not directly correlate to species abundance, they remain a practical and tractable way to assess changes in habitat quality from various restoration actions. As part of the legislatively mandated five year update to the 2012 plan, the wildlife habitat suitability indices were updated and revised using literature and existing field data where available. The outcome of these efforts resulted in improved, or in some cases entirely new suitability indices. This report describes the development of the habitat suitability indices for the American alligator, Alligator mississippiensis.

  11. Molecular cloning of anti-Müllerian hormone from the American alligator, Alligator mississippiensis.

    PubMed

    Urushitani, Hiroshi; Katsu, Yoshinao; Miyagawa, Shinichi; Kohno, Satomi; Ohta, Yasuhiko; Guillette, Louis J; Iguchi, Taisen

    2011-02-20

    Anti-Müllerian hormone (AMH) plays an important role in male sex differentiation in vertebrates. AMH produced by Sertoli cells of the fetal testis induces regression of the Müllerian duct in mammalian species. In alligators, sexual differentiation is controlled by the temperature during egg incubation, termed temperature-dependent sex determination (TSD). The TSD mechanism inducing sex differentiation is thought to be unique and different from that of genetic sex determination as no gene such as the SRY of mammals has been identified. However, many of the genes associated with gonadal differentiation in mammals also are expressed in the developing gonads of species exhibiting TSD. To clarify the molecular mechanisms associated with gonad formation during the temperature-sensitive period (TSP), we have cloned the full length AMH gene in the alligator, and quantitatively compared mRNA expression patterns in the gonad-adrenal-mesonephros (GAM) complex isolated from alligator embryos incubated at male and female producing temperatures. The deduced amino acid sequence of the alligator AMH cDNA showed high identity (59-53%) to avian AMH genes. AMH mRNA expression was high in the GAM of male alligator embryos at stage 24 (immediately after sex determination) and hatchlings, but suppressed in the GAM of estrogen-exposed hatchlings incubated at the male-producing temperature. In the alligator AMH proximal promoter, a number of transcriptional factors (for SF-1. GATA, WT-1 and SOX9) binding elements were also identified and they exhibit a conserved pattern seen in other species. SOX9 up-regulates transcriptional activity through the amAMH promoter region. These results suggested that AMH and SOX9 play important roles in TSD of the American alligator.

  12. Identification and Characterization of the Androgen Receptor From the American Alligator, Alligator mississippiensis

    PubMed Central

    Miyagawa, Shinichi; Yatsu, Ryohei; Kohno, Satomi; Doheny, Brenna M.; Ogino, Yukiko; Ishibashi, Hiroshi; Katsu, Yoshinao; Ohta, Yasuhiko; Guillette, Louis J.

    2015-01-01

    Androgens are essential for the development, reproduction, and health throughout the life span of vertebrates, particularly during the initiation and maintenance of male sexual characteristics. Androgen signaling is mediated by the androgen receptor (AR), a member of the steroid nuclear receptor superfamily. Mounting evidence suggests that environmental factors, such as exogenous hormones or contaminants that mimic hormones, can disrupt endocrine signaling and function. The American alligator (Alligator mississippiensis), a unique model for ecological research in that it exhibits environment-dependent sex determination, is oviparous and long lived. Alligators from a contaminated environment exhibit low reproductive success and morphological disorders of the testis and phallus in neonates and juveniles, both associated with androgen signaling; thus, the alterations are hypothesized to be related to disrupted androgen signaling. However, this line of research has been limited because of a lack of information on the alligator AR gene. Here, we isolated A mississippiensis AR homologs (AmAR) and evaluated receptor-hormone/chemical interactions using a transactivation assay. We showed that AmAR responded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p′-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly, we found a spliced form of the AR from alligator cDNA, which lacks seven amino acids within the ligand-binding domain that shows no response to androgens. Finally, we have initial data on a possible dominant-negative function of the spliced form of the AR against androgen-induced AmAR. PMID:25974402

  13. Identification and Characterization of the Androgen Receptor From the American Alligator, Alligator mississippiensis.

    PubMed

    Miyagawa, Shinichi; Yatsu, Ryohei; Kohno, Satomi; Doheny, Brenna M; Ogino, Yukiko; Ishibashi, Hiroshi; Katsu, Yoshinao; Ohta, Yasuhiko; Guillette, Louis J; Iguchi, Taisen

    2015-08-01

    Androgens are essential for the development, reproduction, and health throughout the life span of vertebrates, particularly during the initiation and maintenance of male sexual characteristics. Androgen signaling is mediated by the androgen receptor (AR), a member of the steroid nuclear receptor superfamily. Mounting evidence suggests that environmental factors, such as exogenous hormones or contaminants that mimic hormones, can disrupt endocrine signaling and function. The American alligator (Alligator mississippiensis), a unique model for ecological research in that it exhibits environment-dependent sex determination, is oviparous and long lived. Alligators from a contaminated environment exhibit low reproductive success and morphological disorders of the testis and phallus in neonates and juveniles, both associated with androgen signaling; thus, the alterations are hypothesized to be related to disrupted androgen signaling. However, this line of research has been limited because of a lack of information on the alligator AR gene. Here, we isolated A mississippiensis AR homologs (AmAR) and evaluated receptor-hormone/chemical interactions using a transactivation assay. We showed that AmAR responded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p'-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly, we found a spliced form of the AR from alligator cDNA, which lacks seven amino acids within the ligand-binding domain that shows no response to androgens. Finally, we have initial data on a possible dominant-negative function of the spliced form of the AR against androgen-induced AmAR.

  14. Acoustic signals of Chinese alligators (Alligator sinensis): social communication.

    PubMed

    Wang, Xianyan; Wang, Ding; Wu, Xiaobing; Wang, Renping; Wang, Chaolin

    2007-05-01

    This paper reports the first systematic study of acoustic signals during social interactions of the Chinese alligator (Alligator sinensis). Sound pressure level (SPL) measurements revealed that Chinese alligators have an elaborate acoustic communication system with both long-distance signal-bellowing-and short-distance signals that include tooting, bubble blowing, hissing, mooing, head slapping and whining. Bellows have high SPL and appear to play an important role in the alligator's long range intercommunion. Sounds characterized by low SPL are short-distance signals used when alligators are in close spatial proximity to one another. The signal spectrographic analysis showed that the acoustic signals of Chinese alligators have a very low dominant frequency, less than 500 Hz. These frequencies are consistent with adaptation to a habitat with high density vegetation. Low dominant frequency sound attenuates less and could therefore cover a larger spatial range by diffraction in a densely vegetated environment relative to a higher dominant frequency sound.

  15. Gene-environment interactions: the potential role of contaminants in somatic growth and the development of the reproductive system of the American alligator.

    PubMed

    Moore, Brandon C; Roark, Alison M; Kohno, Satomi; Hamlin, Heather J; Guillette, Louis J

    2012-05-06

    Developing organisms interpret and integrate environmental signals to produce adaptive phenotypes that are prospectively suited for probable demands in later life. This plasticity can be disrupted when embryos are impacted by exogenous contaminants, such as environmental pollutants, producing potentially deleterious and long-lasting mismatches between phenotype and the future environment. We investigated the ability for in ovo environmental contaminant exposure to alter the growth trajectory and ovarian function of alligators at five months after hatching. Alligators collected as eggs from polluted Lake Apopka, FL, hatched with smaller body masses but grew faster during the first five months after hatching, as compared to reference-site alligators. Further, ovaries from Lake Apopka alligators displayed lower basal expression levels of inhibin beta A mRNA as well as decreased responsiveness of aromatase and follistatin mRNA expression levels to treatment with follicle stimulating hormone. We posit that these differences predispose these animals to increased risks of disease and reproductive dysfunction at adulthood.

  16. Wildlife Photography - Alligators

    NASA Image and Video Library

    2017-05-08

    An alligator moves through a brackish waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

  17. Wildlife Photography - Alligators

    NASA Image and Video Library

    2017-05-08

    An alligator lurks in a brackish waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

  18. Wildlife Photography - Alligators

    NASA Image and Video Library

    2017-05-04

    Baby alligators gather in a shallow waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

  19. Wildlife Photography - Alligators

    NASA Image and Video Library

    2017-05-04

    An alligator swims in a brackish waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

  20. In ovo and in vitro susceptibility of American alligators (Alligator mississippiensis) to avian influenza virus infection.

    PubMed

    Temple, Bradley L; Finger, John W; Jones, Cheryl A; Gabbard, Jon D; Jelesijevic, Tomislav; Uhl, Elizabeth W; Hogan, Robert J; Glenn, Travis C; Tompkins, S Mark

    2015-01-01

    Avian influenza has emerged as one of the most ubiquitous viruses within our biosphere. Wild aquatic birds are believed to be the primary reservoir of all influenza viruses; however, the spillover of H5N1 highly pathogenic avian influenza (HPAI) and the recent swine-origin pandemic H1N1 viruses have sparked increased interest in identifying and understanding which and how many species can be infected. Moreover, novel influenza virus sequences were recently isolated from New World bats. Crocodilians have a slow rate of molecular evolution and are the sister group to birds; thus they are a logical reptilian group to explore susceptibility to influenza virus infection and they provide a link between birds and mammals. A primary American alligator (Alligator mississippiensis) cell line, and embryos, were infected with four, low pathogenic avian influenza (LPAI) strains to assess susceptibility to infection. Embryonated alligator eggs supported virus replication, as evidenced by the influenza virus M gene and infectious virus detected in allantoic fluid and by virus antigen staining in embryo tissues. Primary alligator cells were also inoculated with the LPAI viruses and showed susceptibility based upon antigen staining; however, the requirement for trypsin to support replication in cell culture limited replication. To assess influenza virus replication in culture, primary alligator cells were inoculated with H1N1 human influenza or H5N1 HPAI viruses that replicate independent of trypsin. Both viruses replicated efficiently in culture, even at the 30 C temperature preferred by the alligator cells. This research demonstrates the ability of wild-type influenza viruses to infect and replicate within two crocodilian substrates and suggests the need for further research to assess crocodilians as a species potentially susceptible to influenza virus infection.

  1. Molecular and functional characterization of BAFF from the Yangtze alligator (Alligator sinensis, Alligatoridae).

    PubMed

    Zhang, Jia-Xin; Song, Ren; Sang, Ming; Sun, Si-Qing; Ma, Lei; Zhang, Jie; Zhang, Shuang-Quan

    2015-10-01

    B-cell activating factor (BAFF) from the TNF family is critical for B-cell survival and maturation. In this study, we identified a Yangtze alligator (Alligator sinensis, Alligatoridae) BAFF cDNA, designated as asBAFF, using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The open reading frame of this cDNA encodes a 287-amino acid protein containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian and avian BAFF. The amino acid identity between biologically soluble asBAFF (assBAFF) and csBAFF, hsBAFF, and msBAFF is 94, 76, and 71%, respectively. Real-time quantitative PCR analysis showed that the asBAFF gene is strongly expressed in the spleen. Since BAFF is always expressed as inclusion bodies in bacteria, it is difficult to purify. To enhance the soluble expression of assBAFF in Escherichia coli, we fused the extracellular region of the asBAFF gene to a small ubiquitin-related modifier gene (SUMO). Purified assBAFF was able to promote the survival of splenic lymphocytes and co-stimulate the proliferation of mouse B cells with anti-mouse IgM. These findings suggest that asBAFF plays an important role in the survival and proliferation of Yangtze alligator B cells, and because it is evolutionarily highly conserved, functional cross-reactivity exists between mammalian and Yangtze alligator BAFF.

  2. A big alligator snacks on a smaller alligator

    NASA Technical Reports Server (NTRS)

    1998-01-01

    A large alligator attacks and eats a smaller one in a natural display of cannibalism. Although this event has been observed infrequently by Kennedy Space Center's staff photographers, it is common feeding behavior among the wild alligator population on the space center. Alligators are carnivorous and will eat any living thing that crosses their paths and is small enough for them to kill. For this reason, it is dangerous to feed wild alligators, and in Florida, it is also illegal. Kennedy Space Center is located on the Merritt Island National Wildlife Refuge which is operated by the U.S. Fish and Wildlife Service.

  3. A big alligator snacks on a smaller alligator

    NASA Technical Reports Server (NTRS)

    1998-01-01

    A large alligator attacks and eats a smaller one in a natural display of cannibalism. Although this event has been observed infrequently by Kennedy Space Center's staff photographers, it is common feeding behavior among the wild alligator population on the space center. Alligators are carnivorous and will eat any living thing that crosses their paths and is small enough for them to kill. For this reason, it is dangerous to feed wild alligators, and in Florida, it is also illegal. Kennedy Space Center is located on the Merritt Island National Wildlife Refuge which is operated by the U.S. Fish and Wildlife Service.

  4. Physiological thermoregulation of mature alligators.

    PubMed

    Smith, E N; Standora, E A; Robertson, S L

    1984-01-01

    A 67.1 kg alligator (Alligator mississippiensis), tested in air, heated twice as fast as it cooled. The cooling thermal time constant was 425 min while alive. Warming and cooling thermal time constants were 421 min after death. The thermal time constant was not appropriate in describing warming in air of mature alligators. Surface and subdermal heat flow measurements of the 67.1 kg animal indicate greater blood flow in the skin during warming compared to cooling. Two mature alligators, 49.9 and 103 kg, were heated and cooled in water. Warming time constants were 67 and 110 min respectively. Cooling time constants were 180 and 246 min. Data from this study were combined with previously published thermal time constants for alligators providing regression equations for alligators ranging from 37 g to 103 kg. Regression equations for alligators tested in water are: tau w = 8.81 M050 tau c = 12.6 M0.62. Time constants (tau) are in minutes (w = warming, c = cooling) with all measurements in stirred water; mass, M, is in kg. Thermal conductance and metabolism data are combined to provide an estimate of the amount the body temperature of theoretical alligators ranging from 50 g to 1000 kg would be elevated by metabolism. A body temperature of 34.2 degrees C is predicted for a 1000 kg theoretical alligator in 30 degrees C water.

  5. Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis)

    PubMed Central

    Tate, Kevin B.; Rhen, Turk; Eme, John; Kohl, Zachary F.; Crossley, Janna; Elsey, Ruth M.

    2016-01-01

    During embryonic development, environmental perturbations can affect organisms' developing phenotype, a process known as developmental plasticity. Resulting phenotypic changes can occur during discrete, critical windows of development. Critical windows are periods when developing embryos are most susceptible to these perturbations. We have previously documented that hypoxia reduces embryo size and increases relative heart mass in American alligator, and this study identified critical windows when hypoxia altered morphological, cardiovascular function and cardiac gene expression of alligator embryos. We hypothesized that incubation in hypoxia (10% O2) would increase relative cardiac size due to cardiac enlargement rather than suppression of somatic growth. We exposed alligator embryos to hypoxia during discrete incubation periods to target windows where the embryonic phenotype is altered. Hypoxia affected heart growth between 20 and 40% of embryonic incubation, whereas somatic growth was affected between 70 and 90% of incubation. Arterial pressure was depressed by hypoxic exposure during 50–70% of incubation, whereas heart rate was depressed in embryos exposed to hypoxia during a period spanning 70–90% of incubation. Expression of Vegf and PdgfB was increased in certain hypoxia-exposed embryo treatment groups, and hypoxia toward the end of incubation altered β-adrenergic tone for arterial pressure and heart rate. It is well known that hypoxia exposure can alter embryonic development, and in the present study, we have identified brief, discrete windows that alter the morphology, cardiovascular physiology, and gene expression in embryonic American alligator. PMID:27101296

  6. Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis).

    PubMed

    Tate, Kevin B; Rhen, Turk; Eme, John; Kohl, Zachary F; Crossley, Janna; Elsey, Ruth M; Crossley, Dane A

    2016-06-01

    During embryonic development, environmental perturbations can affect organisms' developing phenotype, a process known as developmental plasticity. Resulting phenotypic changes can occur during discrete, critical windows of development. Critical windows are periods when developing embryos are most susceptible to these perturbations. We have previously documented that hypoxia reduces embryo size and increases relative heart mass in American alligator, and this study identified critical windows when hypoxia altered morphological, cardiovascular function and cardiac gene expression of alligator embryos. We hypothesized that incubation in hypoxia (10% O2) would increase relative cardiac size due to cardiac enlargement rather than suppression of somatic growth. We exposed alligator embryos to hypoxia during discrete incubation periods to target windows where the embryonic phenotype is altered. Hypoxia affected heart growth between 20 and 40% of embryonic incubation, whereas somatic growth was affected between 70 and 90% of incubation. Arterial pressure was depressed by hypoxic exposure during 50-70% of incubation, whereas heart rate was depressed in embryos exposed to hypoxia during a period spanning 70-90% of incubation. Expression of Vegf and PdgfB was increased in certain hypoxia-exposed embryo treatment groups, and hypoxia toward the end of incubation altered β-adrenergic tone for arterial pressure and heart rate. It is well known that hypoxia exposure can alter embryonic development, and in the present study, we have identified brief, discrete windows that alter the morphology, cardiovascular physiology, and gene expression in embryonic American alligator. Copyright © 2016 the American Physiological Society.

  7. Environmentally relevant concentrations of nitrate increase plasma testosterone concentrations in female American alligators (Alligator mississippiensis).

    PubMed

    Hamlin, Heather J; Edwards, Thea M; McCoy, Jessica; Cruze, Lori; Guillette, Louis J

    2016-11-01

    Anthropogenic nitrogen is a ubiquitous environmental contaminant that is contributing to the degradation of freshwater, estuarine, and coastal ecosystems worldwide. The effects of environmental nitrate, a principal form of nitrogen, on the health of aquatic life is of increasing concern. We exposed female American alligators to three concentrations of nitrate (0.7, 10 and 100mg/L NO3-N) for a duration of five weeks and five months from hatch. We assessed growth, plasma sex steroid and thyroid hormone concentrations, and transcription levels of key genes involved in steroidogenesis (StAR, 3β-HSD, and P450scc) and hepatic clearance (Cyp1a, Cyp3a). Exposure to 100mg/L NO3-N for both five weeks and five months resulted in significantly increased plasma testosterone (T) concentrations compared with alligators in the reference treatment. No differences in 17β-estradiol, progesterone, or thyroid hormones were observed, nor were there differences in alligator weight or the mRNA abundance of steroidogenic or hepatic genes. Plasma and urinary nitrate concentrations increased with increasing nitrate treatment levels, although relative plasma concentrations of nitrate were significantly lower in five month, versus five week old animals, possibly due to improved kidney function in older animals. These results indicate that environmentally relevant concentrations of nitrate can increase circulating concentrations of T in young female alligators. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. The 'Angry Alligator'

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Augmented Target Docking Adapter (ATDA) as seen from the Gemini 9 spacecraft during one of their three rendezvous in space. The ATDA and Gemini 9 spacecraft are 66.5 ft. apart. Failure of the docking adapter protective cover to fully separate on the ATDA prevented the docking of the two spacecraft. The ATDA was described by the Gemini 9 crew as an 'angry alligator.'

  9. Hox expression in the American alligator and evolution of archosaurian axial patterning.

    PubMed

    Mansfield, Jennifer H; Abzhanov, Arhat

    2010-12-15

    The avian body plan has undergone many modifications, most associated with adaptation to flight and bipedal walking. Some of these modifications may be owing to avian-specific changes in the embryonic Hox expression code. Here, we have examined Hox expression in alligator, the closest living relative of birds, and an archosaur with a more conservative body plan. Two differences in Hox expression between chick, alligator, and other tetrapods correlate with aspects of alligator or bird-specific skeletal morphology. First, absence of a thoracic subdomain of Hoxc-8 expression in alligator correlates with morphological adaptations in crocodilian thoracic segments. Second, Hoxa-5, a gene required to pattern the cervical-thoracic transition, shows unique patterns of expression in chick, alligator, and mouse, correlating with species-specific morphological patterning of this region. Given that cervical vertebral morphologies evolved independently in the bird and mammalian lineages, the underlying developmental mechanisms, including refinement of Hox expression domains, may be distinct.

  10. Gene – environment interactions: the potential role of contaminants in somatic growth and the development of the reproductive system of the American alligator

    PubMed Central

    Moore, Brandon C.; Roark, Alison M.; Kohno, Satomi; Hamlin, Heather J.; Guillette, Louis J.

    2011-01-01

    Developing organisms interpret and integrate environmental signals to produce adaptive phenotypes that are prospectively suited for probable demands in later life. This plasticity can be disrupted when embryos are impacted by exogenous contaminants, such as environmental pollutants, producing potentially deleterious and long-lasting mismatches between phenotype and the future environment. We investigated the ability for in ovo environmental contaminant exposure to alter the growth trajectory and ovarian function of alligators at five months after hatching. Alligators collected as eggs from polluted Lake Apopka, FL, hatched with smaller body masses but grew faster during the first five months after hatching, as compared to reference-site alligators. Further, ovaries from Lake Apopka alligators displayed lower basal expression levels of inhibin beta A mRNA as well as decreased responsiveness of aromatase and follistatin mRNA expression levels to treatment with follicle stimulating hormone. We posit that these differences predispose these animals to increased risks of disease and reproductive dysfunction at adulthood. PMID:22061623

  11. OOGENESIS AND OVARIAN HISTOLOGY OF THE AMERICAN ALLIGATOR ALLIGATOR MISSISSIPPIENSIS

    EPA Science Inventory

    Although folliculogenesis and oogenesis have been observed in numerous reptiles, these phenomena have not been described in detail in a crocodilian. Oogenesis and histological features of the adult ovary of Alligator mississippiensis are described. Using a complex process, the ov...

  12. OOGENESIS AND OVARIAN HISTOLOGY OF THE AMERICAN ALLIGATOR ALLIGATOR MISSISSIPPIENSIS

    EPA Science Inventory

    Although folliculogenesis and oogenesis have been observed in numerous reptiles, these phenomena have not been described in detail in a crocodilian. Oogenesis and histological features of the adult ovary of Alligator mississippiensis are described. Using a complex process, the ov...

  13. Alligators as West Nile Virus Amplifiers

    PubMed Central

    Klenk, Kaci; Snow, Jamie; Morgan, Katrina; Bowen, Richard; Stephens, Michael; Foster, Falicia; Gordy, Paul; Beckett, Susan; Komar, Nicholas; Gubler, Duane; Bunning, Michel

    2004-01-01

    Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators. PMID:15663852

  14. Alligators as West Nile virus amplifiers.

    PubMed

    Klenk, Kaci; Snow, Jamie; Morgan, Katrina; Bowen, Richard; Stephens, Michael; Foster, Falicia; Gordy, Paul; Beckett, Susan; Komar, Nicholas; Gubler, Duane; Bunning, Michel

    2004-12-01

    Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators.

  15. Mercury in alligators (Alligator mississippiensis) in the southeastern United States

    USGS Publications Warehouse

    Jagoe, C.H.; Arnold-Hill, B.; Yanochko, G.M.; Winger, P.V.; Brisbin, I.L.

    1998-01-01

    Mercury methylation may be enhanced in wetlands and humic-rich, blackwater systems that crocodiles and alligators typically inhabit. Given their high trophic level and long life-spans, crocodilians could accumulate significant burdens of Hg. Our objectives were to survey Hg concentrations in alligators from several areas in the southeastern United States to test their utility as sentinels of Hg contamination, to examine relationships among Hg concentrations in various tissues and to look for any differences in tissue Hg concentrations among locations. We measured total Hg concentrations in alligators collected in the Florida Everglades (n = 18), the Okefenokee National Wildlife Refuge, Georgia (n = 9), the Savannah River Site (SRS), South Carolina (n = 49) and various locations in central Florida ( n = 21), sampling tissues including blood, brain, liver, kidney, muscle, bone, fat, spleen, claws and dermal scutes. Alligators from the Everglades were mostly juvenile, but Hg concentrations in tissues were high (means: liver 41.0, kidney 36.4, muscle 5.6 mg Hg/kg dry wt.). Concentrations in alligators from other locations in Florida were lower (means: liver 14.6, kidney 12.6, muscle 1.8 mg Hg/kg dry wt.), although they tended to be larger adults. Alligators from the Okefenokee were smallest and had the lowest Hg concentrations (means: liver 4.3, kidney 4.8, muscle 0.8 mg Hg/kg dry wt.). At some locations, alligator length was correlated with Hg concentrations in some internal organs. However, at three of the four locations, muscle Hg was not related to length. Tissue Hg concentrations were correlated at most locations; however, claw or dermal scute Hg explained less than 74% of the variation of Hg in muscle or organs, suggesting readily-obtained tissues, such as scutes or claws, have limited value for nondestructive screening of Hg in alligator populations.

  16. Essential fatty acid nutrition of the American alligator (Alligator mississippiensis).

    PubMed

    Staton, M A; Edwards, H M; Brisbin, I L; Joanen, T; McNease, L

    1990-07-01

    The essential fatty acid (EFA) nutrition of young American alligators (Alligator mississippiensis) was examined by feeding a variety of fats/oils with potential EFA activity. Over a 12-wk period, alligators fed diets containing 2.5 or 5.0% chicken liver oil grew longer and heavier and converted feed to body mass more efficiently than alligators fed other fat/oil combinations that lacked or contained only trace amounts of arachidonic acid [20:4(n-6)]. Alligators fed an EFA-deficient diet (containing only coconut fat as the dietary fat) were the slowest-growing animals and converted feed to body mass least efficiently. However, over a 41-wk feeding period, alligators fed this diet showed no obvious external signs of deficiency other than being reduced in size and unthrifty. Fatty acid composition of heart, liver, muscle, skin and adipose tissue lipids was influenced markedly by dietary fat composition. Tissues varied significantly in response to dietary fat composition. Heart lipids contained the lowest levels of short- and medium-chain fatty acids and the highest levels of arachidonic acid. Arachidonic acid levels were less influenced by diet than were levels of other 20- and 22-carbon polyunsaturated fatty acids. Radiotracer studies indicated that linoleic acid was converted to arachidonic acid in the liver. Nevertheless, tissue arachidonic acid levels also appeared to be maintained by concentration from dietary sources and selective conservation. It appears that a dietary source of arachidonic acid may be required for a maximum rate of growth.

  17. Trace element biodistribution in the American alligator (Alligator mississippiensis).

    PubMed

    Nilsen, Frances M; Kassim, Brittany L; Delaney, J Patrick; Lange, Ted R; Brunell, Arnold M; Guillette, Louis J; Long, Stephen E; Schock, Tracey B

    2017-08-01

    Routine monitoring of contaminant levels in wildlife is important for understanding chemical exposure and ultimately the link to ecosystem and human health. This is particularly important when the monitored species is recreationally hunted for human consumption. In the southeastern United States, recreational alligator harvesting takes place annually and in locations that are known to be contaminated with environmental pollutants. In this study, we investigated the biodistribution of trace elements in the American alligator (Alligator mississippiensis) from five sites in Florida, USA. These sites are locations where annual recreational alligator harvesting is permitted and two of the sites are identified as having high mercury contamination with human consumption advisories in effect. We utilized routinely collected monitoring samples (blood and scute), a commonly consumed tissue (muscle), and a classically analyzed tissue for environmental contaminants (liver) to demonstrate how the trace elements were distributed within the American alligator. We describe elemental tissue compartmentalization in an apex predator and investigate if noninvasive samples (blood and scute) can be used to estimate muscle tissue concentrations for a subset of elements measured. We found significant correlations for Hg, Rb, Se, Zn and Pb between noninvasive samples and consumed tissue and also found that Hg was the only trace metal of concern for this population of alligators. This study fills a gap in trace elemental analysis for reptilian apex predators in contaminated environments. Additionally, comprehensive elemental analysis of routinely collected samples can inform biomonitoring efforts and consumption advisories. Published by Elsevier Ltd.

  18. Morphological and molecular characterization of Ortleppascaris sinensis sp. nov. (Nematoda: Ascaridoidea) from the Chinese alligator Alligator sinensis.

    PubMed

    Zhao, J H; Wang, S S; Tu, G J; Zhou, Y K; Wu, X B

    2016-05-01

    A new nematode species, Ortleppascaris sinensis sp. nov. (Ascaridoidea), is described from specimens found in the stomach and intestine of the Chinese alligator Alligator sinensis Fauvel, 1879 (Crocodilian: Alligatoridae) in the National Nature Reserve of Chinese Alligator (Chinese Crocodile Lake) in Anhui Province, China. This is the first description of O. sinensis sp. nov. in both China and this crocodile host, increasing its distribution in South Asia as well as expanding the number of helminths known to infect this crocodile. The detailed description of O. sinensis sp. nov., based on light and scanning electron microscopic examination, provides new taxonomic data for this species, and we also report sequences of the internal transcribed spacers (ITS), small subunit DNA segments (18S) and the cytochrome oxidase I (COI) gene.

  19. Mortality of American alligators attributed to cannibalism

    USGS Publications Warehouse

    Delany, Michael F.; Woodward, Allan R.; Kiltie, Richard A.; Moore, Clinton T.

    2011-01-01

    Mortality of juvenile (Alligator mississippiensis) attributed to cannibalism on Orange Lake, Florida was examined. Alligator web tags used in mark–recapture studies were found in 12% of 267 stomachs sampled from alligators ≥168 cm TL. Captive alligators retained 76% of force-fed tags during a 588-d tag-retention trial. Models relating the probability of tag recovery to the annual probabilities of juvenile survival, cannibalism, tag retention, adult survival, and adult harvest suggested that cannibalism may on average remove 6–7% of the juvenile alligator population annually. Vulnerability continued to 140 cm TL (age 6–8 yr). Cannibalism of juveniles may serve to regulate the alligator population on Orange Lake. Alligator cannibalism may vary widely among populations, depending on demography and environmental conditions. The role and importance of cannibalism in alligator population dynamics should be more fully assessed and environmental and population factors that influence cannibalism identified to better evaluate management programs.

  20. Developmental morphology of the neonatal alligator (Alligator mississippiensis) ovary.

    PubMed

    Moore, Brandon C; Uribe-Aranzábal, Mari Carmen; Boggs, Ashley S P; Guillette, Louis J

    2008-03-01

    American alligator (Alligator mississippiensis) ovary development is incomplete at hatching. During the months following hatching, the cortical processes of oogenesis started in ovo continues and folliculogenesis is initiated. Additionally, the medullary region of the gonad undergoes dramatic restructuring. We describe alligator ovarian histology at hatching, 1 week, 1 month, and 3 months of age in order to characterize the timing of morphological development and compare these findings to chicken ovary development. At hatching, the ovarian cortex presents a germinal epithelium containing oogonia and a few primary oocytes irregularly scattered between somatic epithelial cells. The hatchling medulla shows fragmentation indicative of the formation of lacunae. By 1 week of age, oocytes form growing nests and show increased interactions with somatic cells, indicative of the initiation of folliculogenesis. Medullary lacunae increase in diameter and contain secretory material in their lumen. At 1 month, nest sizes and lacunar diameters continue to enlarge. Pachytene oocytes surrounded by somatic cells are more frequent. Trabeculae composed of dense irregular connective tissue divide cortical nests. Three months after hatching oocytes in meiotic stages of prophase I up to diplotene are present. The ovary displays many enlarged follicles with oocytes in diplotene arrest, thecal layers, lampbrush chromosomes, and complete layers of follicular cells. The medulla is an elaborated complex of vascularized lacunae underlying the cortex and often containing discrete lymphoid aggregates. While the general morphology of the alligator ovary is similar to that of the chicken ovary, the progression of oogenesis and folliculogenesis around hatching is notably slower in alligators. Diplotene oocytes are observed at hatching in chickens, but not until 3 months in alligators. Folliculogenesis is completed at 3 weeks in chickens whereas it is still progressing at 3 months in alligators.

  1. Epigenetic programming alterations in alligators from environmentally contaminated lakes.

    PubMed

    Guillette, Louis J; Parrott, Benjamin B; Nilsson, Eric; Haque, M M; Skinner, Michael K

    2016-11-01

    Previous studies examining the reproductive health of alligators in Florida lakes indicate that a variety of developmental and health impacts can be attributed to a combination of environmental quality and exposures to environmental contaminants. The majority of these environmental contaminants have been shown to disrupt normal endocrine signaling. The potential that these environmental conditions and contaminants may influence epigenetic status and correlate to the health abnormalities was investigated in the current study. The red blood cell (RBC) (erythrocyte) in the alligator is nucleated so was used as an easily purified marker cell to investigate epigenetic programming. RBCs were collected from adult male alligators captured at three sites in Florida, each characterized by varying degrees of contamination. While Lake Woodruff (WO) has remained relatively pristine, Lake Apopka (AP) and Merritt Island (MI) convey exposures to different suites of contaminants. DNA was isolated and methylated DNA immunoprecipitation (MeDIP) was used to isolate methylated DNA that was then analyzed in a competitive hybridization using a genome-wide alligator tiling array for a MeDIP-Chip analysis. Pairwise comparisons of alligators from AP and MI to WO revealed alterations in the DNA methylome. The AP vs. WO comparison identified 85 differential DNA methylation regions (DMRs) with ⩾3 adjacent oligonucleotide tiling array probes and 15,451 DMRs with a single oligo probe analysis. The MI vs. WO comparison identified 75 DMRs with the ⩾3 oligo probe and 17,411 DMRs with the single oligo probe analysis. There was negligible overlap between the DMRs identified in AP vs. WO and MI vs. WO comparisons. In both comparisons DMRs were primarily associated with CpG deserts which are regions of low CpG density (1-2CpG/100bp). Although the alligator genome is not fully annotated, gene associations were identified and correlated to major gene class functional categories and pathways of

  2. Alligators, contaminants and steroid hormones.

    PubMed

    Guillette, Louis J; Edwards, Thea M; Moore, Brandon C

    2007-01-01

    Steroids are essential for successful reproduction in all vertebrate species. Over the last several decades, extensive research has indicated that exposure to various environmental pollutants can disrupt steroidogenesis and steroid signaling. Although steroidogenesis is regulated by the hypothalamic-pituitary axis, it is also modified by various paracrine and autocrine factors. Furthermore, the classical two-cell model of steroidogenesis in the developing ovarian follicle, involving the granulosa and theca cells in mammals, may not be universal. Instead, birds and probably reptiles use the two thecal compartments (theca interna and theca externa) as sites of steroid production. We have documented that embryonic or juvenile exposure to a complex mixture of contaminants from agricultural and storm water runoff leads to altered steroid hormone profiles in American alligators. Our observations suggest that alterations in plasma steroid hormone concentrations are due in part to altered gene expression, modified hepatic biotransformation and altered gonadal steroidogenesis. Future studies must examine the interplay between endocrine and paracrine regulation in the development and expression of gonadal steroidogenesis in individuals exposed to endocrine disrupting contaminants at various life stages if we are to fully understand potential detrimental outcomes.

  3. Developmental plasticity of mitochondrial function in American alligators, Alligator mississippiensis

    PubMed Central

    Crossley, Janna; Elsey, Ruth M.; Dzialowski, Edward M.; Shiels, Holly A.; Crossley, Dane A.

    2016-01-01

    The effect of hypoxia on cellular metabolism is well documented in adult vertebrates, but information is entirely lacking for embryonic organisms. The effect of hypoxia on embryonic physiology is particularly interesting, as metabolic responses during development may have life-long consequences, due to developmental plasticity. To this end, we investigated the effects of chronic developmental hypoxia on cardiac mitochondrial function in embryonic and juvenile American alligators (Alligator mississippiensis). Alligator eggs were incubated in 21% or 10% oxygen from 20 to 90% of embryonic development. Embryos were either harvested at 90% development or allowed to hatch and then reared in 21% oxygen for 3 yr. Ventricular mitochondria were isolated from embryonic/juvenile alligator hearts. Mitochondrial respiration and enzymatic activities of electron transport chain complexes were measured with a microrespirometer and spectrophotometer, respectively. Developmental hypoxia induced growth restriction and increased relative heart mass, and this phenotype persisted into juvenile life. Embryonic mitochondrial function was not affected by developmental hypoxia, but at the juvenile life stage, animals from hypoxic incubations had lower levels of Leak respiration and higher respiratory control ratios, which is indicative of enhanced mitochondrial efficiency. Our results suggest developmental hypoxia can have life-long consequences for alligator morphology and metabolic function. Further investigations are necessary to reveal the adaptive significance of the enhanced mitochondrial efficiency in the hypoxic phenotype. PMID:27707718

  4. Developmental plasticity of mitochondrial function in American alligators, Alligator mississippiensis.

    PubMed

    Galli, Gina L J; Crossley, Janna; Elsey, Ruth M; Dzialowski, Edward M; Shiels, Holly A; Crossley, Dane A

    2016-12-01

    The effect of hypoxia on cellular metabolism is well documented in adult vertebrates, but information is entirely lacking for embryonic organisms. The effect of hypoxia on embryonic physiology is particularly interesting, as metabolic responses during development may have life-long consequences, due to developmental plasticity. To this end, we investigated the effects of chronic developmental hypoxia on cardiac mitochondrial function in embryonic and juvenile American alligators (Alligator mississippiensis). Alligator eggs were incubated in 21% or 10% oxygen from 20 to 90% of embryonic development. Embryos were either harvested at 90% development or allowed to hatch and then reared in 21% oxygen for 3 yr. Ventricular mitochondria were isolated from embryonic/juvenile alligator hearts. Mitochondrial respiration and enzymatic activities of electron transport chain complexes were measured with a microrespirometer and spectrophotometer, respectively. Developmental hypoxia induced growth restriction and increased relative heart mass, and this phenotype persisted into juvenile life. Embryonic mitochondrial function was not affected by developmental hypoxia, but at the juvenile life stage, animals from hypoxic incubations had lower levels of Leak respiration and higher respiratory control ratios, which is indicative of enhanced mitochondrial efficiency. Our results suggest developmental hypoxia can have life-long consequences for alligator morphology and metabolic function. Further investigations are necessary to reveal the adaptive significance of the enhanced mitochondrial efficiency in the hypoxic phenotype. Copyright © 2016 the American Physiological Society.

  5. Molecular characterization of dental development in a toothed archosaur, the American alligator Alligator mississippiensis.

    PubMed

    Weeks, Olivia; Bhullar, Bhart-Anjan S; Abzhanov, Arhat

    2013-01-01

    Few skeletal structures are as informative of the adaptive natural history of vertebrate animals as their teeth. Understanding principles of tooth development is key to understanding evolution of the vertebrate dentition in general and emergence of multiple specialized tooth types in particular. Morphological and phylogenetic considerations suggest that crocodilians have the most primitive mode of dentition within extant tetrapods, displaying simple, conical, socketed, and continuously replaced teeth. Previous histological studies revealed several dental fates, including functional and non-functional teeth (rudiments) in the developing alligator embryos. We analyze expression of key odontogenic regulators and markers to better characterize the molecular patterning of crocodilian dentition. Importantly, we demonstrate that the morphologically distinct tooth types in Alligator mississippiensis are distinguishable by differences in their developmental programs. We also present evidence showing that tooth maturation is accompanied by dynamic gene expression in the epithelial and mesenchymal cells involved in tooth development. Our data reveal a significant morphological and genetic variation in early dental fates. We believe that this underlying developmental variation reflects modularity, or the ability of teeth to develop semi-autonomously along the alligator jaw. We propose that such modularity may have been a crucial for adaptive evolution within Amniota, allowing for the progressive modifications to tooth replacement, number, and shape.

  6. Growth rates of Chinese and American alligators.

    PubMed

    Herbert, J D; Coulson, T D; Coulson, R A

    2002-04-01

    Growth rates in two closely related species, Alligator mississippiensis (American alligator) and Alligator sinensis (Chinese alligator), were compared under identical conditions for at least 1 year after hatching. When hatched, Chinese alligators were approximately 2/3 the length and approximately 1/2 the weight of American alligator hatchlings. At the end of 1 year of growth in captivity in heated chambers, the Chinese alligators were approximately 1/2 as long and weighed approximately 1/10 as much as American alligator yearlings. When the animals were maintained at 31 degrees C, Chinese alligator food consumption and length gain rates dropped to near zero during autumn and winter and body weights decreased slightly, apparently in response to the change in day length. At constant temperature (31 degrees C), food consumption by American alligators remained high throughout the year. Length gain rates in American alligators decreased slowly as size increased, but were not affected by photoperiod. Daily weight gains in American alligators increased steadily throughout the year. In autumn, provision of artificial light for 18 h a day initially stimulated both length and weight gain in Chinese alligators, but did not affect growth in American alligators. Continuation of the artificial light regimen seemed to cause deleterious effects in the Chinese alligators after several months, however, so that animals exposed to the normal light cycle caught up to and then surpassed the extra-light group in size. Even after removal of the artificial light, it was several months before these extra-light animals reverted to a normal growth pattern. These findings may be of interest to those institutions engaged in captive growth programs intended to provide animals for reintroduction to the wild or to protected habitat.

  7. Alligator diet in relation to alligator mortality on Lake Griffin, FL

    USGS Publications Warehouse

    Rice, A.N.; Ross, J.P.; Woodward, A.R.; Carbonneau, D.A.; Percival, H.F.

    2007-01-01

    Alligator mississippiensis (American Alligators) demonstrated low hatch-rate success and increased adult mortality on Lake Griffin, FL, between 1998 and 2003. Dying Lake Griffin alligators with symptoms of poor motor coordination were reported to show specific neurological impairment and brain lesions. Similar lesions were documented in salmonines that consumed clupeids with high thiaminase levels. Therefore, we investigated the diet of Lake Griffin alligators and compared it with alligator diets from two lakes that exhibited relatively low levels of unexplained alligator mortality to see if consumption of Dorosoma cepedianum (gizzard shad) could be correlated with patterns of mortality. Shad in both lakes Griffin and Apopka had high levels of thiaminase and Lake Apopka alligators were consuming greater amounts of shad relative to Lake Griffin without showing mortality rates similar to Lake Griffin alligators. Therefore, a relationship between shad consumption alone and alligator mortality is not supported.

  8. Seroprevalence of Mycoplasma alligatoris among free-ranging alligators (Alligator mississippiensis) in Florida--2003.

    PubMed

    Brown, Daniel R; Zacher, Laurie A; Carbonneau, Dwayne A

    2005-06-01

    Mycoplasma alligatoris causes acute lethal infection of alligators (Alligator mississippiensis). The objective of this study was to assess the current seroprevalence of M. alligatoris among free-ranging, juvenile and subadult alligators in Florida. Thirty-two of 592 (5.4%) plasma samples from alligators at 12 of 20 sites (60%) in April and October 2003 were tested seropositive (titer 1: > or = 32) by enzyme-linked immunosorbent assay for anti-M. alligatoris antibodies. These results show that alligators throughout Florida have a recent history of exposure to M. alligatoris and suggest that contact with free-ranging alligators may constitute a risk of lethal infection of susceptible crocodilians.

  9. AFFINITY OF THE ALLIGATOR ESTROGEN RECEPTOR FOR SERUM PESTICIDE CONTAMINANTS

    EPA Science Inventory

    Top predators, like the American alligator (Alligator mississippiensis) bioaccumulate and biomagnify persistent pollutants, such as organochlorine pesticides. In a recently published study, several pesticides and pesticide metabolites not previously reported in alligator eggs wer...

  10. AFFINITY OF THE ALLIGATOR ESTROGEN RECEPTOR FOR SERUM PESTICIDE CONTAMINANTS

    EPA Science Inventory

    Top predators, like the American alligator (Alligator mississippiensis) bioaccumulate and biomagnify persistent pollutants, such as organochlorine pesticides. In a recently published study, several pesticides and pesticide metabolites not previously reported in alligator eggs wer...

  11. Structural design and mechanical behavior of alligator (Alligator mississippiensis) osteoderms.

    PubMed

    Sun, Chang-Yu; Chen, Po-Yu

    2013-11-01

    Alligator is a well-adapted living fossil covered with dorsal armor. This dermal shield consists of bony plates, called osteoderms, interconnected by sutures and non-mineralized collagen fibers, providing a dual function of protection and flexibility. Osteoderm features a sandwich structure, combining an inner porous core and an outer dense cortex, to offer enhancements for stiffness and energy absorbance. In this study, we investigated the multi-scale structure and mechanical behaviors of the American alligator (Alligator mississippiensis) osteoderm. Microcomputed tomography was applied to reveal the complex neurovascular network. Through the observation under optical and scanning electron microscopes, the osteoderm was found to consist of woven bone in the dorsal region and lamellar-zonal bone in the ventral region. Nanoindentation and compressive tests were performed to evaluate the mechanical properties of osteoderms. The varying mineral contents and porosity result in a graded mechanical property: a hard and stiff dorsal cortex gradually transform to a more compliant ventral base. Three protective mechanisms optimized for alligator osteoderms were proposed and elucidated.

  12. Pathology of experimental mycoplasmosis in American alligators.

    PubMed

    Brown, D R; Nogueira, M F; Schoeb, T R; Vliet, K A; Bennett, R A; Pye, G W; Jacobson, E R

    2001-10-01

    Mycoplasma alligatoris was the suspected etiology of an epidemic of acute multisystemic inflammatory disease which emerged in captive American alligators (Alligator mississippiensis) in Florida (USA) in 1995. In an experimental inoculation study conducted from April through October 1999, 18 alligators were inoculated with 10(2), 10(4), or 10(6) colony forming units (CFU) of M. alligatoris by instillation into the glottis. As early as 1 wk post-inoculation (PI), mycoplasma were cultured from blood of three of six alligators inoculated with 10(6) CFU. Two of those died and the third was euthanatized within 4 wk PI. Necropsy gross findings included fibrinous polyserositis and polyarthritis. Histopathologic changes in affected individuals included pulmonary edema, interstitial pneumonia, pericarditis, myocarditis, meningitis, and synovitis. Mycoplasma were cultured quantitatively in high numbers from trachea, lung, coelomic cavity, liver, spleen, interior of pericardial sac, heart, blood, brain, and limb joints. In alligators inoculated with 10(6) CFU, heterophilia and moderate hyperglycemia peaked about 4 wk PI, and seroconversion occurred by 6 to 8 wk PI. Necropsy gross and histologic findings were generally unremarkable for the surviving alligators inoculated with 10(6) CFU, alligators inoculated with 10(2) or 10(4) CFU, and four uninoculated control alligators. Mycoplasma were not cultured at any time point from those alligators. The findings confirm that M. alligatoris can cause fulminant inflammatory disease and rapid death of alligators.

  13. Morphology and histochemistry of juvenile American alligator (Alligator mississippiensis) nephrons.

    PubMed

    Moore, Brandon C; Hyndman, Kelly A; Cox, Ashley; Lawler, Ashley; Mathavan, Ketan; Guillette, Louis J

    2009-10-01

    Here we present a detailed morphological description of the alligator (Alligator mississippiensis) kidney and nephron. We present a series of histological, histochemical, and immunohistochemical markers that clearly define the seven regions of the alligator nephron. The alligator kidney is composed of many paired (mirrored) lobules on each kidney (lobe). Single nephrons span the width of lobules three times. The fine structure of glomeruli, lying in rows spanning the height of the lobule, is resolved by periodic acid methionine silver (PAMS) and periodic acid Schiff's (PAS) histochemistry. Glomeruli are connected to the proximal tubule (PT) via a neck segment. The PT is alcian blue-negative, making it distinct from the distal tubule (DT), connecting segment (CS), and collecting duct (CD). The PT is clearly identifiable by a PAS-positive brush border membrane. The PT is connected to the DT via an intermediate segment (IS) that makes a 180 degrees turn to connect these tubules. PAMS-positive material is found in the lumens of the PT, IS, and DT. Also, PAMS-positive granules are found in the DT, CS, and CD. Immunolocalization of the Na(+), K(+)-ATPase to the basolateral membrane of the DT, CS, and CD suggests a role of this enzyme in driving primary and secondary transport processes in these segments, including bicarbonate transport into the lumen of the DT (leading to an alkaline urine). Through the techniques described here, we have identified a series of distinct markers to be used by pathologists, veterinarians, and researchers to easily identify alligator nephron segments. Anat Rec, 2009. (c) 2009 Wiley-Liss, Inc.

  14. Alligators in the Sewers? Really?

    ERIC Educational Resources Information Center

    Egbert, Joy

    2009-01-01

    A large number of alligators, flushed down toilets as babies, have grown up and proliferated in the bowels of New York City. Over the years, they have grown in number and size and frequently terrorize those foolish enough to visit the subways. This tale has been making its way around the Internet ever since there's been an Internet. It's wild…

  15. Gender differences in haemogregarine infections in American alligators (Alligator mississippiensis) at Savannah River, South Carolina, USA.

    PubMed

    Davis, Andrew K; Horan, Robert V; Grosse, Andrew M; Harris, Bess B; Metts, Brian S; Scott, David E; Tuberville, Tracey D

    2011-10-01

    We report a host gender bias in haemogregarine infection characteristics in the American alligator (Alligator mississippiensis) at the Savannah River Site, South Carolina, USA. Prevalence and severity in female alligators was higher than it was in males. The reason for this pattern is not clear.

  16. Improved genome assembly of American alligator genome reveals conserved architecture of estrogen signaling.

    PubMed

    Rice, Edward S; Kohno, Satomi; John, John St; Pham, Son; Howard, Jonathan; Lareau, Liana F; O'Connell, Brendan L; Hickey, Glenn; Armstrong, Joel; Deran, Alden; Fiddes, Ian; Platt, Roy N; Gresham, Cathy; McCarthy, Fiona; Kern, Colin; Haan, David; Phan, Tan; Schmidt, Carl; Sanford, Jeremy R; Ray, David A; Paten, Benedict; Guillette, Louis J; Green, Richard E

    2017-01-30

    The American alligator, Alligator mississippiensis, like all crocodilians, has temperature-dependent sex determination, in which the sex of an embryo is determined by the incubation temperature of the egg during a critical period of development. The lack of genetic differences between male and female alligators leaves open the question of how the genes responsible for sex determination and differentiation are regulated. Insight into this question comes from the fact that exposing an embryo incubated at male-producing temperature to estrogen causes it to develop ovaries. Because estrogen response elements are known to regulate genes over long distances, a contiguous genome assembly is crucial for predicting and understanding their impact. We present an improved assembly of the American alligator genome, scaffolded with in vitro proximity ligation (Chicago) data. We use this assembly to scaffold two other crocodilian genomes based on synteny. We perform RNA sequencing of tissues from American alligator embryos to find genes that are differentially expressed between embryos incubated at male- versus female-producing temperature. Finally, we use the improved contiguity of our assembly along with the current model of CTCF-mediated chromatin looping to predict regions of the genome likely to contain estrogen-responsive genes. We find that these regions are significantly enriched for genes with female-biased expression in developing gonads after the critical period during which sex is determined by incubation temperature. We thus conclude that estrogen signaling is a major driver of female-biased gene expression in the post-temperature sensitive period gonads.

  17. Occurrence of decabromodiphenyl ethane in captive Chinese alligators (Alligator sinensis) from China.

    PubMed

    Hong, Bing; Wu, Ting; Zhao, Guangchao; Sun, Yuxin; Wang, Xinming; Zhao, Juan; Yi, Zhigang; Wu, Xiaobing; Mai, Bixian

    2015-01-01

    Decabromodiphenyl ethane (DBDPE), a replacement for decabromodiphenyl ether (deca-BDE), was investigated in captive Chinese alligators from China. DBDPE was detected in adult tissues, neonates and eggs of Chinese alligators with concentrations ranging from 4.74-192, 0.24-1.94, and 0.01-0.51 ng g(-1) lipid weight, respectively. Compared to PBDEs and PCBs, DBDPE contamination was limited in Chinese alligators. Additionally, DBDPE concentrations in adult muscles were one to three orders of magnitude higher than those in neonates and eggs, suggesting the limited maternal transfer potential of DBDPE in Chinese alligators. This is the first study to report the occurrence of DBDPE in Chinese alligators.

  18. Assessing potential risk to alligators, Alligator mississippiensis, from nutria control with zinc phosphide rodenticide baits.

    PubMed

    Witmer, Gary W; Eisemann, John D; Primus, Thomas M; O'Hare, Jeanette R; Perry, Kelly R; Elsey, Ruth M; Trosclair, Phillip L

    2010-06-01

    Nutria, Myocastor coypus, populations must be reduced when they cause substantial wetland damage. Control can include the rodenticide zinc phosphide, but the potential impacts to American alligators, Alligator mississippiensis, must be assessed. The mean amount of zinc phosphide per nutria found in nutria carcasses was 50 mg. Risk assessment determined that a conservative estimate for maximum exposure would be 173 mg zinc phosphide for a 28 kg alligator, or 6.2 mg/kg. Probit analysis found an LD(50) for alligators of 28 mg/kg. Our studies suggest that the use of zinc phosphide to manage nutria populations would pose only a small risk to alligators.

  19. Distribution of ventilation in American alligator Alligator mississippiensis

    SciTech Connect

    Bickler, P.E.; Spragg, R.G.; Hartman, M.T.; White, F.N.

    1985-10-01

    The regional distribution of ventilation in the multicameral lung of spontaneously ventilating alligators (Alligator mississippiensis) was studied with TTXe scintigraphy. Frequent gamma camera images of TTXe washin and washout were obtained and processed to allow evaluation of regional ventilation. Washin of TTXe to equilibrium occurred in three to four breaths in anterior, central, and posterior compartments. Washin was most rapid in the posterior compartment and slowest in the anterior. The structure of the lungs and distribution of ventilation of inspired gas is consistent with the rapid radial spread of gas through a parallel arrangement of lung units surrounding the central intrapulmonary bronchus. Washout to equilibrium of TTXe from all compartments occurred within three to four breaths. This rapid washin and washout of gas to all parts of the lung stands in contrast to the lungs of turtles and snakes, in which the caudal air sacs are relatively poorly ventilated.

  20. Evaluation of four methods for inducing death during slaughter of American alligators (Alligator mississippiensis).

    PubMed

    Nevarez, Javier G; Strain, George M; da Cunha, Anderson F; Beaufrère, Hugues

    2014-06-01

    To evaluate physical methods for inducing death during the slaughter of American alligators (Alligator mississippiensis). 24 captive hatched-and-reared American alligators. Baseline electroencephalograms (EEGs) were obtained for awake and anesthetized alligators. Corneal reflex, spontaneous blinking, and EEGs were evaluated after severance of the spinal cord, severance of the spinal cord followed by pithing of the brain, application of a penetrating captive bolt, or application of a nonpenetrating captive bolt (6 alligators/group). Overall, alligators subjected to spinal cord severance alone differed from those subjected to the other techniques. Spinal cord severance alone resulted in postprocedure EEG power values greater than those in anesthetized alligators, whereas the postprocedure EEG power values were isoelectric for the other 3 techniques. Corneal reflex and spontaneous blinking were absent in all alligators immediately after application of a penetrating or nonpenetrating captive bolt. One of 6 alligators had a corneal reflex up to 1 minute after pithing, but all others within that group had immediate cessation of reflexes after pithing. Mean time to loss of spontaneous blinking and corneal reflex for alligators subjected to spinal cord severance alone was 18 minutes (range, 2 to 37 minutes) and 54 minutes (range, 34 to 99 minutes), respectively. Spinal cord severance followed by pithing of the brain and application of a penetrating or nonpenetrating captive bolt appeared to be humane and effective techniques for inducing death in American alligators, whereas spinal cord severance alone was not found to be an appropriate method.

  1. Biophysics of directional hearing in the American alligator (Alligator mississippiensis).

    PubMed

    Bierman, Hilary S; Thornton, Jennifer L; Jones, Heath G; Koka, Kanthaiah; Young, Bruce A; Brandt, Christian; Christensen-Dalsgaard, Jakob; Carr, Catherine E; Tollin, Daniel J

    2014-04-01

    Physiological and anatomical studies have suggested that alligators have unique adaptations for spatial hearing. Sound localization cues are primarily generated by the filtering of sound waves by the head. Different vertebrate lineages have evolved external and/or internal anatomical adaptations to enhance these cues, such as pinnae and interaural canals. It has been hypothesized that in alligators, directionality may be enhanced via the acoustic coupling of middle ear cavities, resulting in a pressure difference receiver (PDR) mechanism. The experiments reported here support a role for a PDR mechanism in alligator sound localization by demonstrating that (1) acoustic space cues generated by the external morphology of the animal are not sufficient to generate location cues that match physiological sensitivity, (2) continuous pathways between the middle ears are present to provide an anatomical basis for coupling, (3) the auditory brainstem response shows some directionality, and (4) eardrum movement is directionally sensitive. Together, these data support the role of a PDR mechanism in crocodilians and further suggest this mechanism is a shared archosaur trait, most likely found also in the extinct dinosaurs.

  2. Bioprospecting the American alligator (Alligator mississippiensis) host defense peptidome.

    PubMed

    Bishop, Barney M; Juba, Melanie L; Devine, Megan C; Barksdale, Stephanie M; Rodriguez, Carlos Alberto; Chung, Myung C; Russo, Paul S; Vliet, Kent A; Schnur, Joel M; van Hoek, Monique L

    2015-01-01

    Cationic antimicrobial peptides and their therapeutic potential have garnered growing interest because of the proliferation of bacterial resistance. However, the discovery of new antimicrobial peptides from animals has proven challenging due to the limitations associated with conventional biochemical purification and difficulties in predicting active peptides from genomic sequences, if known. As an example, no antimicrobial peptides have been identified from the American alligator, Alligator mississippiensis, although their serum is antimicrobial. We have developed a novel approach for the discovery of new antimicrobial peptides from these animals, one that capitalizes on their fundamental and conserved physico-chemical properties. This sample-agnostic process employs custom-made functionalized hydrogel microparticles to harvest cationic peptides from biological samples, followed by de novo sequencing of captured peptides, eliminating the need to isolate individual peptides. After evaluation of the peptide sequences using a combination of rational and web-based bioinformatic analyses, forty-five potential antimicrobial peptides were identified, and eight of these peptides were selected to be chemically synthesized and evaluated. The successful identification of multiple novel peptides, exhibiting antibacterial properties, from Alligator mississippiensis plasma demonstrates the potential of this innovative discovery process in identifying potential new host defense peptides.

  3. Environmental influence on yolk steroids in American alligators (Alligator mississippiensis).

    PubMed

    Hamlin, Heather J; Lowers, Russell H; Albergotti, Lori C; McCoy, Michael W; Mutz, Jessica; Guillette, Louis J

    2010-11-01

    The egg yolk serves as a significant source of maternally derived steroids that are available to the embryo during early development. Altered deposition of yolk steroids can change the developmental trajectory of the embryo and have long lasting or permanent consequences. Alligators from contaminated environments have shown significant reproductive and developmental dysfunction, and it is unclear if altered deposition of yolk steroids could be a contributing factor. Alligator eggs were collected from Lake Woodruff (a reference lake), Lake Apopka (a site of known agricultural contamination), and the Merritt Island National Wildlife Refuge (MINWR) (home of the Kennedy Space Center and a site of heavy metal contamination). The yolks of eggs at embryonic stages 12 (prior to sex determination) and 24 (post-sex determination) were evaluated for concentrations of progesterone, 17-beta estradiol, and testosterone. Yolk concentrations of progesterone were significantly lower at embryonic stage 12 in eggs from Lake Apopka and MINWR when compared to eggs from Lake Woodruff. Yolk concentrations of 17-beta estradiol were significantly lower at embryonic stage 12 in eggs from MINWR when compared to the other two sites. Reductions in yolk 17-beta estradiol concentrations from embryonic stage 12 to 24 were significantly attenuated in eggs from MINWR versus that of Lakes Woodruff and Apopka. This study suggests that altered deposition of yolk steroids, and possibly differential utilization by the embryo, could be a contributory mechanism in the reproductive and developmental abnormalities seen in alligators from contaminated locales.

  4. Biophysics of directional hearing in the American alligator (Alligator mississippiensis)

    PubMed Central

    Bierman, Hilary S.; Thornton, Jennifer L.; Jones, Heath G.; Koka, Kanthaiah; Young, Bruce A.; Brandt, Christian; Christensen-Dalsgaard, Jakob; Carr, Catherine E.; Tollin, Daniel J.

    2014-01-01

    Physiological and anatomical studies have suggested that alligators have unique adaptations for spatial hearing. Sound localization cues are primarily generated by the filtering of sound waves by the head. Different vertebrate lineages have evolved external and/or internal anatomical adaptations to enhance these cues, such as pinnae and interaural canals. It has been hypothesized that in alligators, directionality may be enhanced via the acoustic coupling of middle ear cavities, resulting in a pressure difference receiver (PDR) mechanism. The experiments reported here support a role for a PDR mechanism in alligator sound localization by demonstrating that (1) acoustic space cues generated by the external morphology of the animal are not sufficient to generate location cues that match physiological sensitivity, (2) continuous pathways between the middle ears are present to provide an anatomical basis for coupling, (3) the auditory brainstem response shows some directionality, and (4) eardrum movement is directionally sensitive. Together, these data support the role of a PDR mechanism in crocodilians and further suggest this mechanism is a shared archosaur trait, most likely found also in the extinct dinosaurs. PMID:24671963

  5. Bioprospecting the American Alligator (Alligator mississippiensis) Host Defense Peptidome

    PubMed Central

    Bishop, Barney M.; Juba, Melanie L.; Devine, Megan C.; Barksdale, Stephanie M.; Rodriguez, Carlos Alberto; Chung, Myung C.; Russo, Paul S.; Vliet, Kent A.; Schnur, Joel M.; van Hoek, Monique L.

    2015-01-01

    Cationic antimicrobial peptides and their therapeutic potential have garnered growing interest because of the proliferation of bacterial resistance. However, the discovery of new antimicrobial peptides from animals has proven challenging due to the limitations associated with conventional biochemical purification and difficulties in predicting active peptides from genomic sequences, if known. As an example, no antimicrobial peptides have been identified from the American alligator, Alligator mississippiensis, although their serum is antimicrobial. We have developed a novel approach for the discovery of new antimicrobial peptides from these animals, one that capitalizes on their fundamental and conserved physico-chemical properties. This sample-agnostic process employs custom-made functionalized hydrogel microparticles to harvest cationic peptides from biological samples, followed by de novo sequencing of captured peptides, eliminating the need to isolate individual peptides. After evaluation of the peptide sequences using a combination of rational and web-based bioinformatic analyses, forty-five potential antimicrobial peptides were identified, and eight of these peptides were selected to be chemically synthesized and evaluated. The successful identification of multiple novel peptides, exhibiting antibacterial properties, from Alligator mississippiensis plasma demonstrates the potential of this innovative discovery process in identifying potential new host defense peptides. PMID:25671663

  6. Jumping the Alligators in the Ditch.

    ERIC Educational Resources Information Center

    Barber, Rims

    Poor black young people in rural Mississippi contemplate their schooling with the same feelings as their friends who dare to jump the local ditches filled with alligators: the odds are against escaping the alligators, and the advantages of getting to the far side are not very apparent. Living in conditions of extreme poverty, these young people…

  7. Isolation of faecal coliform bacteria from the American alligator (Alligator mississippiensis).

    PubMed

    Johnston, M A; Porter, D E; Scott, G I; Rhodes, W E; Webster, L F

    2010-03-01

    To determine whether American alligators (Alligator mississippiensis) are an unrecognized poikilothermic source of faecal coliform and/or potential pathogenic bacteria in South Carolina's coastal waters. Bacteria from the cloaca of American alligators, as well as bacteria from surface water samples from their aquatic habitat, were isolated and identified. The predominant enteric bacteria identified from alligator samples using biochemical tests included Aeromonas hydrophila, Citrobacter braakii, Edwardsiella tarda, Escherichia coli, Enterobacter cloacae, Plesiomonas shigelloides and putative Salmonella, and these were similar to bacteria isolated from the surface waters in which the alligators inhabited. Based on most-probable-number enumeration estimates from captive alligator faeces, faecal coliform bacteria numbered 8.0x10(9) g(-1) (wet weight) of alligator faecal material, a much higher concentration than many other documented endothermic animal sources. A prevalence of enteric bacteria, both faecal coliforms and potential pathogens, was observed in American alligators. The high faecal coliform bacterial density of alligator faeces may suggest that alligators are a potential source of bacterial contamination in South Carolina coastal waters. These findings help to increase our understanding of faecal coliform and potential pathogenic bacteria from poikilothermic reptilian sources, as there is the potential for these sources to raise bacterial water quality levels above regulatory thresholds.

  8. Sex steroid and thyroid hormone receptor expressions in the thyroid of the American alligator (Alligator mississippiensis) during different life stages.

    PubMed

    Bermudez, Dieldrich S; Skotko, Jeremy P; Ohta, Yasuhiko; Boggs, Ashley S P; Iguchi, Taisen; Guillette, Louis J

    2011-06-01

    The expression of estrogen receptors, ESR1 (ERα) and ESR2 (ERβ), and androgen receptors (AR) in the thyroid gland has been reported in few vertebrate species other than a few mammals. This study reports the presence of sex steroid hormone receptors and thyroid receptors (ERα, ERβ, AR, TRα, and TRβ) in the thyroid gland of the American alligator at several life stages. It provides a semiquantification and distribution of ERα in the thyroid follicle cells using an immunohistochemical approach as well as reports quantitative differences in mRNA expression of ERα, ERβ, TRα, TRβ, and AR in the same tissue using quantitative real time-PCR (Q-PCR) with primers designed specifically for alligators. The thyroid tissue of the American alligator expresses ERα, ERβ, and AR at all of the life stages examined here although no statistically significant differences were observed between male and female in thyroid mRNA expression for any of the genes analyzed. No sexual dimorphism was observed in ERα immunostaining. No statistical analysis across life stages were performed due to confounding factor of season. Copyright © 2011 Wiley-Liss, Inc.

  9. Initial antibiotic therapy for alligator bites: characterization of the oral flora of Alligator mississippiensis.

    PubMed

    Flandry, F; Lisecki, E J; Domingue, G J; Nichols, R L; Greer, D L; Haddad, R J

    1989-02-01

    An open thumb fracture resulting from an alligator bite became infected with Aeromonas hydrophila, Enterobacter agglomerans, and Citrobacter diversus. The patient was treated by surgical debridement and antibiotic therapy. We obtained cultures from the mouth of ten alligators to characterize their oral flora. Initial empiric therapy after alligator bites should be directed at gram-negative species, in particular, Aeromonas hydrophila and anaerobic species including Clostridium. Of the numerous fungi that were isolated, none has been reported to result in wound infection after alligator bites.

  10. Methyltestosterone alters sex determination in the American alligator (Alligator mississippiensis).

    PubMed

    Murray, Christopher M; Easter, Michael; Merchant, Mark; Rheubert, Justin L; Wilson, Kelly A; Cooper, Amos; Mendonça, Mary; Wibbels, Thane; Marin, Mahmood Sasa; Guyer, Craig

    2016-09-15

    Effects of xenobiotics can be organizational, permanently affecting anatomy during embryonic development, and/or activational, influencing transitory actions during adulthood. The organizational influence of endocrine-disrupting contaminants (EDC's) produces a wide variety of reproductive abnormalities among vertebrates that exhibit temperature-dependent sex determination (TSD). Typically, such influences result in subsequent activational malfunction, some of which are beneficial in aquaculture. For example, 17-αmethyltestosterone (MT), a synthetic androgen, is utilized in tilapia farming to bias sex ratio towards males because they are more profitable. A heavily male-biased hatchling sex ratio is reported from a crocodile population near one such tilapia operation in Guanacaste, Costa Rica. In this study we test the effects of MT on sexual differentiation in American alligators, which we used as a surrogate for all crocodilians. Experimentally, alligators were exposed to MT in ovo at standard ecotoxicological concentrations. Sexual differentiation was determined by examination of primary and secondary sex organs post hatching. We find that MT is capable of producing male embryos at temperatures known to produce females and demonstrate a dose-dependent gradient of masculinization. Embryonic exposure to MT results in hermaphroditic primary sex organs, delayed renal development and masculinization of the clitero-penis (CTP).

  11. Coronary blood flow in the anesthetized American alligator (Alligator mississippiensis).

    PubMed

    Jensen, Bjarke; Elfwing, Magnus; Elsey, Ruth M; Wang, Tobias; Crossley, Dane A

    2016-01-01

    Coronary circulation of the heart evolved early within ectothermic vertebrates and became of vital importance to cardiac performance in some teleost fish, mammals and birds. In contrast, the role and function of the coronary circulation in ectothermic reptiles remains largely unknown. Here, we investigated the systemic and coronary arterial responses of five anesthetized juvenile American alligators (Alligator mississippiensis) to hypoxia, acetylcholine, adenosine, sodium nitroprusside, isoproterenol, and phenylephrine. We recorded electrocardiograms, monitored systemic blood pressure, blood flows in both aortae, and blood flow in a major coronary artery supplying most of the right ventricle. Coronary arterial blood flow was generally forward, but there was a brief retrograde flow during a ventricular contraction. Blood pressure was significantly changed in all conditions. Acetylcholine decreased coronary forward flow, but this response was confounded by the concomitant lowered work of the ventricles due to decreased heart rate and blood pressure. Coronary forward flow was poorly correlated with heart rate and mean arterial pressure across treatments. Overall changes in coronary forward flow, significant and not significant, were generally in the same direction as mean arterial pressure and ventricular power, approximated as the product of systemic cardiac output and mean arterial pressure.

  12. On the variability of alligator sex ratios

    USGS Publications Warehouse

    Nichols, J.D.; Chabreck, R.H.

    1980-01-01

    Samples of alligators from wild and 'farm' populations exhibited disproportionate sex ratios. Males predominated among young alligators from wild populations, whereas females were much more abundant than males in the farm population, where resources were superabundant. These results and other considerations lead us to hypothesize that environmental factors influence sex determination in alligators. During favorable environmental conditions natural selection is expected to favor a preponderance of the sex whose individuals exhibit the greater environmentally associated variation in relative fitness. We hypothesize that environmentally associated variation in age at sexual maturity of females produces sufficient variation in relative fitness of females to result in selection for low sex ratios during periods of resource abundance.

  13. Why do Chinese alligators (Alligator sinensis) form bellowing choruses: a playback approach.

    PubMed

    Wang, Xianyan; Wang, Ding; Zhang, Song; Wang, Chaolin; Wang, Renping; Wu, Xiaobing

    2009-10-01

    Crocodilians are quite vocal relative to other reptile groups, and the alligators are among the most vocal of the crocodilians. The Chinese alligator, Alligator sinensis, is usually solitary but engages in bellowing choruses in certain waters during the mating season. This paper reports the organization of Chinese alligator's bellowing choruses based upon field observations and playback experiments. Alligators of both genders engaged in the choruses, remaining immobile throughout and inclining toward bellowing synchronously (i.e., starting and finishing at about the same time). The choruses lasted about 10 min with abrupt onset and offset. Moreover, playback experiments revealed that both male and female alligators responded equally to bellowing stimuli from the same and opposite sexes and that none of the tested alligators approached the loudspeaker in spite of playback of male or female stimuli. These suggest that Chinese alligators may not bellow to compete for or attract mates during the choruses. Instead, when their ecological behaviors, namely, dispersed inhabitation, multi-copulation, restricted mating season, etc., are considered, we hypothesize that they may synchronize bellows to enhance group detectability for assembling individuals into certain waters for subsequent copulations.

  14. Chronic incidental lead ingestion in a group of captive-reared alligators (Alligator mississippiensis): possible contribution to reproductive failure.

    PubMed

    Lance, Valentine A; Horn, Thomas R; Elsey, Ruth M; de Peyster, Ann

    2006-01-01

    An American alligator (Alligator mississippiensis) breeding facility using male and female alligators raised from artificially incubated eggs was established in 1975. These alligators first reproduced at 6 years of age as compared to 10-12 years in wild alligators, but the eggs produced showed a lower hatching rate than those collected from the wild. By age 21 reproduction had failed almost completely. The alligators were sacrificed and tissues collected at necropsy from 44 captive and 15 wild animals and assayed for metals. Results showed that captive alligators had significantly higher tissue levels of lead than wild alligators. Cadmium did not differ between wild and captive and selenium was 50% higher in wild than captive alligator kidneys. Bone lead in captive alligators was 252,443 +/- 20,462 ng/g. High yolk lead was suggested as a probable cause for early embryonic death in alligator eggs. The high tissue lead levels in captive alligators was attributed to long-term consumption of nutria (Myocastor coypus) meat contaminated with lead shot. Liver, ovary, and testis were assayed for lipid peroxidation using the thiobarbituric acid (TBA) test. Captive alligators had 3.6 fold increased TBA-reactive materials in the liver tissue compared to wild. Lipid peroxidation was strongly suspected as having been enhanced by consumption of rancid nutria meat containing lead.

  15. Alligator mississippiensis (American Alligator): Novel non-native prey

    USGS Publications Warehouse

    Elsey, Ruth M.; Ledet, Eric; Carter, Jacoby

    2017-01-01

    A. mississippiensis diet often varies due to regional limitation in prey availability (Neill 1971. The Last of the Ruling Reptiles. Alligators, Crocodiles, and their Kin. Columbia University Press, New York. 486 pp.; Gabrey 2010. Herpetol. Conserv. Biol. 5:241–250). Additionally, differential digestion rates can lead to over-representation of materials resistant to digestion or under-representation of rapidly digested soft-bodied prey items (Jackson et al. 1974. J. Herpetol. 8:378–381; Garnett 1985. J. Herpetol. 19:303–304; Delany and Abercrombie 1986. J. Wildl. Manage. 50:348–353; Platt et al. 1990. Northeast. Gulf Sci. 11:123–130). We herein report on a novel prey item for A. mississippiensis, which to our knowledge has not previously been reported.

  16. POPS IN ALLIGATOR LIVERS FROM LAKE APOPKA, FLORIDA, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  17. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    EPA Science Inventory

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  18. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    EPA Science Inventory

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  19. POPS IN ALLIGATOR LIVERS FROM LAKE APOPKA, FLORIDA, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  20. EFFECTS OF PLANT PROTEIN DIETS ON THE HEALTH OF FARMED AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS).

    PubMed

    DiGeronimo, Peter M; Di Girolamo, Nicola; Crossland, Nicholas A; Del Piero, Fabio; Reigh, Robert C; Nevarez, Javier G

    2017-03-01

    The objective of this prospective, blinded study was to compare plasma biochemical values and gross and histologic evaluation of kidney and liver from American alligators ( Alligator mississippiensis ) fed extruded diets with protein derived from animal or plant sources. Alligators in two treatment groups were fed an extruded diet with protein derived primarily from plant products for 7 (n = 20) or 10 (n = 20) mo prior to harvest. A control group (n = 20) was fed a commercial diet with protein derived from animal products for the duration of the study. Plasma biochemistry panels were obtained and gross and histologic examination of kidney and liver tissues was conducted for each animal. No differences were found between alligators fed diets with animal or plant protein in terms of either biochemistry profiles or gross or histologic examination of kidney and liver. Plant-based diets, fed for up to 10 mo, do not appear to have any ill effects on the kidney or liver of American alligators.

  1. THYROID STATUS IN JUVENILE ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED AND REFERENCE SITES ON LAKE OKEECHOBEE, FLORIDA, USA

    EPA Science Inventory

    Exposure to environmental contaminants has been shown to alter normal thyroid function in various wildlife species, including the American alligator (Alligator mississippiensis). Abnormalities in circulating levels of the thyroid hormone thyroxine (T4) have been reported in juven...

  2. THYROID STATUS IN JUVENILE ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED AND REFERENCE SITES ON LAKE OKEECHOBEE, FLORIDA, USA

    EPA Science Inventory

    Exposure to environmental contaminants has been shown to alter normal thyroid function in various wildlife species, including the American alligator (Alligator mississippiensis). Abnormalities in circulating levels of the thyroid hormone thyroxine (T4) have been reported in juven...

  3. 75 FR 34365 - Safety Zone, Alligator River, NC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Alligator River, NC AGENCY: Coast Guard... the waters of the Alligator River at East Lake, North Carolina. The safety zone is intended to... on the Alligator River makes safety zone regulations necessary to provide for the safety of...

  4. Adverse encounters with alligators in the United States: an update.

    PubMed

    Langley, Ricky L

    2010-06-01

    Severe injuries and fatalities can occur from an alligator attack. Encounters with alligators appear to be increasing in the United States. This review provides information from alligator attacks reported in the United States as well as infections that may occur after an alligator bite. Telephone interviews were conducted with state wildlife offices in all Southern states in order to collect information on the number of alligator bites, nuisance calls, and the estimated alligator population of each state. Detailed information from alligator attacks in Florida is presented, including basic demographic information on the victims and description of the types of injuries and the activity of the victim at the time of injury. Additional information regarding the size and behavior of the alligator involved in the attack is also provided in many cases. There have been 567 reports of adverse encounters with alligators with 24 deaths reported in the United States from 1928 to January 1, 2009. In addition, thousands of nuisance calls are made yearly and the number of nuisance calls as well as the alligator population is increasing in many states. Injuries from encounters with alligators may range from minor scratches and punctures to amputations and death. The larger the alligator, the more likely that serious injury will occur. As the human population encroaches on the habitat of the alligator, attacks and nuisance complaints will continue to occur. A uniform reporting system among states should be developed to obtain more complete information on alligator encounters. Guidelines have been developed by many state wildlife officials to reduce adverse encounters with alligators. Copyright (c) 2010 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  5. Genome analysis and signature discovery for diving and sensory properties of the endangered Chinese alligator.

    PubMed

    Wan, Qiu-Hong; Pan, Sheng-Kai; Hu, Li; Zhu, Ying; Xu, Peng-Wei; Xia, Jin-Quan; Chen, Hui; He, Gen-Yun; He, Jing; Ni, Xiao-Wei; Hou, Hao-Long; Liao, Sheng-Guang; Yang, Hai-Qiong; Chen, Ying; Gao, Shu-Kun; Ge, Yun-Fa; Cao, Chang-Chang; Li, Peng-Fei; Fang, Li-Ming; Liao, Li; Zhang, Shu; Wang, Meng-Zhen; Dong, Wei; Fang, Sheng-Guo

    2013-09-01

    Crocodilians are diving reptiles that can hold their breath under water for long periods of time and are crepuscular animals with excellent sensory abilities. They comprise a sister lineage of birds and have no sex chromosome. Here we report the genome sequence of the endangered Chinese alligator (Alligator sinensis) and describe its unique features. The next-generation sequencing generated 314 Gb of raw sequence, yielding a genome size of 2.3 Gb. A total of 22 200 genes were predicted in Alligator sinensis using a de novo, homology- and RNA-based combined model. The genetic basis of long-diving behavior includes duplication of the bicarbonate-binding hemoglobin gene, co-functioning of routine phosphate-binding and special bicarbonate-binding oxygen transport, and positively selected energy metabolism, ammonium bicarbonate excretion and cardiac muscle contraction. Further, we elucidated the robust Alligator sinensis sensory system, including a significantly expanded olfactory receptor repertoire, rapidly evolving nerve-related cellular components and visual perception, and positive selection of the night vision-related opsin and sound detection-associated otopetrin. We also discovered a well-developed immune system with a considerable number of lineage-specific antigen-presentation genes for adaptive immunity as well as expansion of the tripartite motif-containing C-type lectin and butyrophilin genes for innate immunity and expression of antibacterial peptides. Multifluorescence in situ hybridization showed that alligator chromosome 3, which encodes DMRT1, exhibits significant synteny with chicken chromosome Z. Finally, population history analysis indicated population admixture 0.60-1.05 million years ago, when the Qinghai-Tibetan Plateau was uplifted.

  6. Genome analysis and signature discovery for diving and sensory properties of the endangered Chinese alligator

    PubMed Central

    Wan, Qiu-Hong; Pan, Sheng-Kai; Hu, Li; Zhu, Ying; Xu, Peng-Wei; Xia, Jin-Quan; Chen, Hui; He, Gen-Yun; He, Jing; Ni, Xiao-Wei; Hou, Hao-Long; Liao, Sheng-Guang; Yang, Hai-Qiong; Chen, Ying; Gao, Shu-Kun; Ge, Yun-Fa; Cao, Chang-Chang; Li, Peng-Fei; Fang, Li-Ming; Liao, Li; Zhang, Shu; Wang, Meng-Zhen; Dong, Wei; Fang, Sheng-Guo

    2013-01-01

    Crocodilians are diving reptiles that can hold their breath under water for long periods of time and are crepuscular animals with excellent sensory abilities. They comprise a sister lineage of birds and have no sex chromosome. Here we report the genome sequence of the endangered Chinese alligator (Alligator sinensis) and describe its unique features. The next-generation sequencing generated 314 Gb of raw sequence, yielding a genome size of 2.3 Gb. A total of 22 200 genes were predicted in Alligator sinensis using a de novo, homology- and RNA-based combined model. The genetic basis of long-diving behavior includes duplication of the bicarbonate-binding hemoglobin gene, co-functioning of routine phosphate-binding and special bicarbonate-binding oxygen transport, and positively selected energy metabolism, ammonium bicarbonate excretion and cardiac muscle contraction. Further, we elucidated the robust Alligator sinensis sensory system, including a significantly expanded olfactory receptor repertoire, rapidly evolving nerve-related cellular components and visual perception, and positive selection of the night vision-related opsin and sound detection-associated otopetrin. We also discovered a well-developed immune system with a considerable number of lineage-specific antigen-presentation genes for adaptive immunity as well as expansion of the tripartite motif-containing C-type lectin and butyrophilin genes for innate immunity and expression of antibacterial peptides. Multifluorescence in situ hybridization showed that alligator chromosome 3, which encodes DMRT1, exhibits significant synteny with chicken chromosome Z. Finally, population history analysis indicated population admixture 0.60-1.05 million years ago, when the Qinghai-Tibetan Plateau was uplifted. PMID:23917531

  7. Seasonal variation in plasma thyroxine concentrations in juvenile alligators (Alligators mississippiensis) from three Florida Lakes.

    PubMed

    Bermudez, Dieldrich S; Milnes, Matthew R; Bryan, Teresa A; Gunderson, Mark P; Tubbs, Christopher; Woodward, Allan R; Guillette, Louis J

    2005-05-01

    Circulating concentrations of thyroxine (T(4)) vary seasonally in many vertebrates. This study examined the seasonal variation in plasma concentrations of T(4) in juvenile American alligators (Alligator mississippiensis) from three populations in central Florida, USA. One site, Lake Woodruff National Wildlife Refuge, is considered a reference site whereas the other two lakes, Lake Apopka and Orange Lake, are significantly impacted by human activity. Juvenile American alligators ranging from 75-150 cm in total length were hand-captured at night from November 2000-April 2002. Plasma thyroxine concentrations were analyzed using a radioimmunoassay (RIA) previously validated for alligator plasma. Juvenile American alligators display seasonal variation in circulating T(4) concentrations. Plasma T(4) concentrations decrease from August/September to November and then begin a slow rise until April, at which point they plateau. Sex of juveniles influenced plasma concentrations of T(4) in some months but did not appear to alter the pattern in seasonal variation. The pattern we observed in plasma T(4) concentrations is not directly related to an environmental factor such as ambient temperature but is similar to that seen in plasma sex steroid concentrations during the reproductive cycle of adult alligators. Although the pattern and plasma concentration of T(4) exhibits significant variation among the three lakes studied, the pattern in seasonal variation appears similar. Comparing the seasonal pattern in plasma T(4) with plasma concentrations of sex steroids (testosterone and estradiol-17beta) or corticosterone could provide important information on the peripubescent life stage of the American alligator.

  8. Molecular cloning, characterization, tissue distribution and mRNA expression changes during the hibernation and reproductive periods of estrogen receptor alpha (ESR1) in Chinese alligator, Alligator sinensis.

    PubMed

    Zhang, Ruidong; Hu, Yuehong; Wang, Huan; Yan, Peng; Zhou, Yongkang; Wu, Rong; Wu, Xiaobing

    2016-10-01

    Chinese alligator, Alligator sinensis, is a critically endangered reptile species unique to China. Little is known about the mechanism of growth- and reproduction-related hormones gene expression in Chinese alligator. Estrogens play important roles in regulating multiple reproduction- and non-reproduction-related functions by binding to their corresponding receptors. Here, the full-length cDNA of estrogen receptor alpha (ERα/ESR1) was cloned and sequenced from Chinese alligator for the first time, which comprises 1764bp nucleotides and encodes a predicted protein of 587 amino acids. Phylogenetic analysis of ESR1 showed that crocodilians and turtles were the sister-group of birds. The results of real-time quantitative PCR indicated that the ESR1 mRNA was widely expressed in the brain and peripheral tissues. In the brain and pituitary gland, ESR1 was most highly transcribed in the cerebellum. But in other peripheral tissues, ESR1 mRNA expression level was the highest in the ovary. Compared with hibernation period, ESR1 mRNA expression levels were increased significantly in the reproductive period (P<0.05) in cerebellum, pituitary gland, liver, spleen, lung, kidney and ovary, while no significant change in other examined tissues (P>0.05). The ESR1 mRNA expression levels changes during the two periods of different tissues suggested that ESR1 might play an important role in mediation of estrogenic multiple reproductive effects in Chinese alligator. Furthermore, it was the first time to quantify ESR1 mRNA level in the brain of crocodilians, and the distribution and expression of ESR1 mRNA in the midbrain, cerebellum and medulla oblongata was also reported for the first time in reptiles.

  9. Influences of sex, incubation temperature, and environmental quality on gonadal estrogen and androgen receptor messenger RNA expression in juvenile American alligators (Alligator mississippiensis).

    PubMed

    Moore, Brandon C; Milnes, Matthew R; Kohno, Satomi; Katsu, Yoshinao; Iguchi, Taisen; Guillette, Louis J

    2010-01-01

    Gonadal steroid hormone receptors play a vital role in transforming ligand signals into gene expression. We have shown previously that gonads from wild-caught juvenile alligators express greater levels of estrogen receptor 1 (ESR1) than estrogen receptor 2 (ESR2). Furthermore, sexually dimorphic ESR2 mRNA expression (female > male) observed in animals from the reference site (Lake Woodruff, FL, USA) was lost in alligators from the contaminated Lake Apopka (FL, USA). We postulated that environmental contaminant exposure could influence gonadal steroid hormone receptor expression. Here, we address questions regarding gonadal estrogen and androgen receptor (AR) mRNA expression in 1-yr-old, laboratory-raised alligators. What are relative expression levels within gonads? Do these levels vary between sexes or incubation temperatures? Can contaminant exposure change these levels? We observed a similar pattern of expression (ESR1 > AR > ESR2) in ovary and testis. However, both incubation temperature and environment modulated expression. Males incubated at 33.5 degrees C expressed greater AR levels than females incubated at 30 degrees C; dimorphic expression was not observed in animals incubated at 32 degrees C. Compared to Lake Woodruff alligators, Lake Apopka animals of both sexes showed lesser ESR2 mRNA expression levels. Employing cluster analyses, we integrated these receptor expression patterns with those of steroidogenic factors. Elevated ESR2 and CYP19A1 expressions were diagnostic of alligator ovary, whereas elevated HSD3B1, CYP11A1, and CYP17A1 expressions were indicative of testis. In contrast, AR, ESR1, and NR5A1 showed variable expressions that were not entirely associated with sex. These findings demonstrate that the mRNA expression of receptors required for steroid hormone signaling are modified by exposure to environmental factors, including temperature and contaminants.

  10. Influences of Sex, Incubation Temperature, and Environmental Quality on Gonadal Estrogen and Androgen Receptor Messenger RNA Expression in Juvenile American Alligators (Alligator mississippiensis)1

    PubMed Central

    Moore, Brandon C.; Milnes, Matthew R.; Kohno, Satomi; Katsu, Yoshinao; Iguchi, Taisen; Guillette, Louis J.

    2009-01-01

    Gonadal steroid hormone receptors play a vital role in transforming ligand signals into gene expression. We have shown previously that gonads from wild-caught juvenile alligators express greater levels of estrogen receptor 1 (ESR1) than estrogen receptor 2 (ESR2). Furthermore, sexually dimorphic ESR2 mRNA expression (female > male) observed in animals from the reference site (Lake Woodruff, FL, USA) was lost in alligators from the contaminated Lake Apopka (FL, USA). We postulated that environmental contaminant exposure could influence gonadal steroid hormone receptor expression. Here, we address questions regarding gonadal estrogen and androgen receptor (AR) mRNA expression in 1-yr-old, laboratory-raised alligators. What are relative expression levels within gonads? Do these levels vary between sexes or incubation temperatures? Can contaminant exposure change these levels? We observed a similar pattern of expression (ESR1 > AR > ESR2) in ovary and testis. However, both incubation temperature and environment modulated expression. Males incubated at 33.5°C expressed greater AR levels than females incubated at 30°C; dimorphic expression was not observed in animals incubated at 32°C. Compared to Lake Woodruff alligators, Lake Apopka animals of both sexes showed lesser ESR2 mRNA expression levels. Employing cluster analyses, we integrated these receptor expression patterns with those of steroidogenic factors. Elevated ESR2 and CYP19A1 expressions were diagnostic of alligator ovary, whereas elevated HSD3B1, CYP11A1, and CYP17A1 expressions were indicative of testis. In contrast, AR, ESR1, and NR5A1 showed variable expressions that were not entirely associated with sex. These findings demonstrate that the mRNA expression of receptors required for steroid hormone signaling are modified by exposure to environmental factors, including temperature and contaminants. PMID:19759368

  11. An indoor air quality study of an alligator (Alligator mississippiensis) holding facility.

    PubMed

    Wilson, S C; Holder, H W; Martin, J M; Brasel, T L; Andriychuk, L A; Wu, C; Straus, D C; Aguilar, R

    2006-06-01

    An environmental microbiologic investigation was conducted in an alligator (Alligator mississippiensis) holding facility in a zoo in the southeastern U.S. The facility had housed five alligators between March 1999 and February 2005. In the exhibit, one alligator died and all experienced poor health. It was hypothesized that environmental microbial contamination was associated with these issues. Samples were collected for fungal identification and quantification, microcystin analysis, and airborne mycotoxins. Analyses of air and water were conducted and an examination of the heating, ventilation, and air-conditioning system (HVAC) for design, maintenance, and operating issues was made. Two control sites, a facility for false gharials (Tomistoma schlegelii) and an off-site alligator breeding facility, were also tested. Morbidity and mortality records were examined for all sites. Results showed that, compared to the control sites, the test alligator facility and its HVAC system were extensively contaminated with a range of fungi. Nearly all sampled surfaces featured fungal growth. There were also significantly higher counts of Penicillium/Aspergillus-like and Chrysosporium-like spores in the air (P < 0.004). The design, maintenance, and operation of the HVAC system were all inadequate, resulting in poorly conditioned and mold-contaminated air being introduced to the facility. Morbidity records revealed solitary pulmonary disorders over time in three alligators, with one dying as a result. The other two alligators suffered from general malaise and a range of nonspecific symptoms. The control facilities had no morbidity or mortality issues. In conclusion, although no causal links could be demonstrated because of the nature of the morbidity data, environmental mold contamination appeared to be associated with the history of morbidity and mortality in the alligator exhibit.

  12. Alterations in steroidogenesis in alligators (Alligator mississippiensis) exposed naturally and experimentally to environmental contaminants.

    PubMed Central

    Crain, D A; Guillette, L J; Rooney, A A; Pickford, D B

    1997-01-01

    Many environmental contaminants alter the reproduction of animals by altering the development and function of the endocrine system. The ability of environmental contaminants to alter the endocrine system of alligators was studied both in a descriptive study in which juvenile alligators from a historically contaminated lake were compared to animals from a control lake and in an experimental study in which hatchling control alligators were exposed in ovo to several endocrine-disrupting standards and two modern-use herbicides. Endocrine status was assessed by examining plasma hormone concentrations, gonadal-adrenal mesonephros (GAM) aromatase activity, and gonadal histopathology. In the descriptive study, juvenile alligators from the contaminated lake had significantly lower plasma testosterone concentrations (29.2 pg/ml compared to 51.3 pg/ml), whereas plasma 17 beta-estradiol concentrations did not vary when compared to controls. GAM aromatase activity was significantly decreased n the alligators from the contaminated lake (7.6 pmol/g/hr compared to 11.4 pmol/g/hr). In the experimental study, the endocrine-disrupting standards had the expected effects. 17 beta-Estradiol and tamoxifen caused sex reversal from male to female, with a corresponding increase in aromatase activity. Vinclozolin had no apparent effect on male or female alligators. Among the herbicides tested, atrazine induced GAM aromatase activity in male hatchling alligators that was neither characteristic of males nor females, although testicular differentiation was not altered. Exposure to 2,4-dichlorophenoxyacetic acid had no effect on the endocrine parameters that were measured. Together, these studies show that exposure to some environmental chemicals (such as atrazine) can alter steroidogenesis in alligators, but the endocrine alterations previously noted for Lake Apopka, Florida, alligators can not be fully explained by this mechanism. Images Figure 1. PMID:9222139

  13. Endogenous and exogenous estrogens during embryonic development affect timing of hatch and growth in the American alligator (Alligator mississippiensis).

    PubMed

    Cruze, Lori; Roark, Alison M; Rolland, Gabrielle; Younas, Mona; Stacy, Nicole; Guillette, Louis J

    2015-06-01

    Prenatal exposure to estrogenic endocrine disrupting chemicals (EDCs) can affect length of gestation and body mass and size of offspring. However, the dose, timing, and duration of exposure as well as sex and strain of the experimental animals determine the direction and magnitude of these effects. In this study, we examined the effects of a one-time embryonic exposure to either 17 β-estradiol (E2) or bisphenol A (BPA) on rate of development and growth in American alligators (Alligator mississippiensis). Our results indicate that BPA and E2-treated alligators hatched approximately 1.4 days earlier than vehicle-treated (control) alligators, suggesting that estrogenic chemicals hasten hatching in these animals. We assessed growth rates, growth allometry, and body condition for 21 weeks after hatching and found that BPA-treated alligators grew more quickly shortly after hatching but more slowly thereafter compared to control alligators. Conversely, E2-treated alligators grew more slowly shortly after hatching but more quickly thereafter compared to control alligators. As a result of differences in growth rate, BPA-treated alligators were heavier, longer, and fatter than control alligators at age 5 weeks but were similar in size and leaner than control alligators at age 21 weeks. Biochemical analytes were examined at the end of the 21-week study to assess overall metabolic condition. We found that E2-treated alligators had significantly higher circulating plasma concentrations of cholesterol and triglycerides than control alligators while BPA-treated alligators had blood profiles comparable to control alligators. Our results provide important insights into the effects of exogenous estrogens on morphology and metabolism in an oviparous, semi-aquatic reptile. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Nematodes collected by gastric lavage from live American alligators, Alligator mississippiensis, in Florida.

    PubMed

    Waddle, Amanda Rice; Kinsella, John M; Ross, J Perran; Rojas-Flores, Edith; Percival, H Franklin; Forrester, Donald J

    2009-10-01

    Stomach nematodes were collected from 151 live American alligators, Alligator mississippiensis, from 3 lakes (Apopka, Griffin, and Woodruff) in north-central Florida using a gastric lavage technique. Four species were identified: Dujardinascaris waltoni, Ortleppascaris antipini, Brevimulticaecum tenuicolle, and larvae of Contracaecum sp. Of these, D. waltoni was the most prevalent species in all 3 lakes and was more prevalent in Lake Apopka than in the other 2 lakes. This is the first record of Contracaecum larvae in the American alligator and the second record of O. antipini.

  15. Low cost of ventilation in the vagotomised alligator (Alligator mississippiensis).

    PubMed

    Skovgaard, Nini; Wang, Tobias

    2007-10-15

    Pulmonary ventilation requires energy, but the estimated costs of breathing in reptiles vary from 1 to 30% of resting metabolic rate. The low values have been estimated from changes in oxygen uptake during hypoxia or hypercapnia, but it remains possible that these treatments affected metabolism. We equipped alligators with masks for simultaneous measurements of ventilation and oxygen uptake during hypercapnia, hypoxia and bilateral vagotomy. Hypercapnia and hypoxia caused a marked increase in total ventilation, but oxygen uptake remained unchanged indicating a very low energetic cost of breathing. Upon vagotomy, breathing pattern changed to occasional and exceedingly deep breaths (76.1+/-11.1 ml kg(-1)) followed by buccal oscillations and shallower breaths (22.2+/-2.3 ml kg(-1)) interspersed between long non-ventilatory periods. This change in breathing pattern did not affect oxygen uptake. The duration of inspiration increased substantially upon vagotomy, so that inspiratory flow rate did not increase proportionally to tidal volume. These prolonged inspiratory times leads to less flow resistance and may explain that tidal volume could be increased substantially without a measurable energetic cost.

  16. An algae-covered alligator rests warily

    NASA Technical Reports Server (NTRS)

    2000-01-01

    An algae-covered alligator keeps a wary eye open as it rests in one of the ponds at Kennedy Space Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  17. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the water near Kennedy Space Center, a mother alligator gathers her six offspring. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  18. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the water near Kennedy Space Center, a mother alligator gathers her six offspring. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  19. MORPHOLOGICAL VARIATION IN HATCHLING AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM THREE FLORIDA LAKES

    EPA Science Inventory

    Morphological variation of 508 hatchling alligators from three lakes in north central Florida (Lakes Woodruff, Apopka, and Orange) was analyzed using multivariate statistics. Morphological variation was found among clutches as well as among lakes. Principal components analysis wa...

  20. ALTERATIONS IN SEXUALLY DIMORPHIC BIOTRANSFORMATION OF TESTOSTERONE IN JUVENILE AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED LAKES

    EPA Science Inventory

    The goal of this study was to determine whether hepatic biotransformation of testosterone is normally sexually dimorphic in juvenile alligators and whether living in a contaminated environment affects hepatic dimorphism. Lake Woodruff served as our reference site. Moonshine Bay, ...

  1. ALTERATIONS IN SEXUALLY DIMORPHIC BIOTRANSFORMATION OF TESTOSTERONE IN JUVENILE AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED LAKES

    EPA Science Inventory

    The goal of this study was to determine whether hepatic biotransformation of testosterone is normally sexually dimorphic in juvenile alligators and whether living in a contaminated environment affects hepatic dimorphism. Lake Woodruff served as our reference site. Moonshine Bay, ...

  2. MORPHOLOGICAL VARIATION IN HATCHLING AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM THREE FLORIDA LAKES

    EPA Science Inventory

    Morphological variation of 508 hatchling alligators from three lakes in north central Florida (Lakes Woodruff, Apopka, and Orange) was analyzed using multivariate statistics. Morphological variation was found among clutches as well as among lakes. Principal components analysis wa...

  3. METALS AND METALLOIDS IN TISSUES OF AMERICAN ALLIGATORS IN THREE FLORIDA LAKES

    EPA Science Inventory

    Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether ...

  4. METALS AND METALLOIDS IN TISSUES OF AMERICAN ALLIGATORS IN THREE FLORIDA LAKES

    EPA Science Inventory

    Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether ...

  5. TRPV4 associates environmental temperature and sex determination in the American alligator.

    PubMed

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Saito, Shigeru; Lowers, Russell H; Ogino, Yukiko; Fukuta, Naomi; Katsu, Yoshinao; Ohta, Yasuhiko; Tominaga, Makoto; Guillette, Louis J; Iguchi, Taisen

    2015-12-18

    Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual's genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism.

  6. TRPV4 associates environmental temperature and sex determination in the American alligator

    PubMed Central

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Saito, Shigeru; Lowers, Russell H.; Ogino, Yukiko; Fukuta, Naomi; Katsu, Yoshinao; Ohta, Yasuhiko; Tominaga, Makoto; Guillette Jr, Louis J.; Iguchi, Taisen

    2015-01-01

    Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual’s genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism. PMID:26677944

  7. International Alligator Rivers Analog Project

    SciTech Connect

    Bichard, G.F.

    1988-01-01

    The Australian Nuclear Science and Technology Organization (ANSTO), the Japan Atomic Energy Research Institute, the Swedish Nuclear Power Inspectorate, the U.K. Department of the Environment, the US Nuclear Regulatory Commission (NRC), and the Power Reactor and Nuclear Fuel Development Corporation of Japan are participating under the aegis of the Nuclear Energy Agency in the International Alligator Rivers Analog Project. The project has a duration of 3 yr, starting in 1988. The project has grown out of a research program on uranium ore bodies as analogs of high-level waste (HLW) repositories undertaken by ANSTO supported by the NRC. A primary objective of the project is to develop an approach to radionuclide transport model validation that may be used by the participants to support assessments of the safety of radioactive waste repositories. The approach involves integrating mathematical and physical modeling with hydrological and geochemical field and laboratory investigations of the analog site. The Koongarra uranium ore body has been chosen as the analog site because it has a secondary ore body that has formed over the past million years as a result of leaching by groundwater flowing through fractures in the primary ore body.

  8. Home range and movements of American alligators (Alligator mississippiensis) in an estuary habitat

    USGS Publications Warehouse

    Fujisaki, Ikuko; Hart, Kristen M.; Mazzotti, Frank J.; Cherkiss, Michael S.; Sartain-Iverson, Autumn R.; Jeffery, Brian M.; Beauchamp, Jeffrey S.; Denton, Mathew J.

    2014-01-01

    This study reveals consistent use of estuary habitat by American alligators. The alligators showed variations in their movement pattern and seasonal habitat, with movement attributable to environmental factors. Although satellite-derived locations were more dispersed compared to locations collected using VHF radio-tags, data collected from VHF tracking omitted some habitat used for a short period of time, indicating the effectiveness of satellite telemetry to continuously track animals for ecosystem-scale studies.

  9. The isolation of parvalbumin isoforms from the tail muscle of the American alligator (Alligator mississipiensis).

    PubMed

    Laney, E L; Shabanowitz, J; King, G; Hunt, D F; Nelson, D J

    1997-04-01

    Multiple parvalbumin isoforms have been detected in the tail (skeletal) muscle of the American alligator (Alligator mississipiensis). One of these isoforms (APV-1) has been highly purified and partially characterized. Protein purification involved mainly gel filtration and anion exchange chromatography, and characterization included gel electrophoresis, amino acid composition analysis, metal ion analysis, MALDI-TOF and ESI mass spectrometry, ultraviolet and fluorescence spectroscopy, and one- and two-dimensional 500 MHz proton NMR spectroscopy. The alligator isoforms are rich in phenylalanine and deficient in the other aromatic residues as is typical for parvalbumins. In fact, the one highly purified isoform that forms the basis of this study has only phenyl-alanine as an aromatic residue. Ion exchange chromatography further indicates that this isoform has a relatively high isoelectric point (pl approximately 5.0), indicating that it is an alpha-lineage parvalbumin. This alligator parvalbumin isoform is unusual in that it has an atypically high Ca2+ content (almost 3.0 mole of Ca2+ per mole of protein) following purification, a fact supported by terbium fluorescence titration experiments. Preliminary comparative analysis of the highly purified alligator parvalbumin isoform (in the Ca2-loaded state) by two-dimensional 1H-NMR (2D 1H TOCSY and 2D 1H NOESY) indicates that there is considerable similarity in structure between the alligator protein and a homologous protein obtained from the silver hake (a saltwater fish species).

  10. Urinary Phthalate Metabolites in American Alligators (Alligator mississippiensis) from Selected Florida Wetlands.

    PubMed

    Brock, John W; Bell, Jane Margaret; Guillette, Louis J

    2016-07-01

    Phthalates have been shown to cause endocrine disruption in laboratory animals and are associated with altered development of the reproductive system in humans. Further, human have significant exposure to phthalates. However, little is known concerning the exposure of wildlife to phthalates. We report urinary phthalate metabolite concentrations from fifty juvenile alligators from three Florida lakes and a site in the Everglades. Urinary phthalate monoester concentrations varied widely among alligators from the different sites but also among alligators from the same site. Mono-2-ethylhexy phthalate and monobutyl phthalate were found in most samples of alligator urine with maximums of 35,700 ng/mL and 193 ng/mL, respectively. Monobenzyl phthalate was found in 5 alligators with a maximum of 66.7 ng/mL. Other monoesters were found in only one or two alligator urine samples. The wide variation within and among sites, in addition to the high levels of mEHP, mBP and mBzP, is consistent with exposure arising from the intermittent spraying of herbicide formulations to control invasive aquatic plants in Florida freshwater sites. Phthalate diesters are used as adjuvants in many of these formulations.

  11. Material properties of mandibular cortical bone in the American alligator, Alligator mississippiensis.

    PubMed

    Zapata, Uriel; Metzger, Keith; Wang, Qian; Elsey, Ruth M; Ross, Callum F; Dechow, Paul C

    2010-03-01

    This study reports the elastic material properties of cortical bone in the mandible of juvenile Alligator mississippiensis obtained by using an ultrasonic wave technique. The elastic modulus, the shear modulus, and Poisson's ratio were measured on 42 cylindrical Alligator bone specimens obtained from the lingual and facial surfaces of 4 fresh Alligator mandibles. The data suggest that the elastic properties of alligator mandibular cortical bone are similar to those found in mammals and are orthotropic. The properties most resemble those found in the cortex of mammalian postcranial long bones where the bone is most stiff in one direction and much less stiff in the two remaining orthogonal directions. This is different from cortical bone found in the mandibles of humans and some monkeys, where the bone has greatest stiffness in one direction, much less stiffness in another direction, and an intermediate amount in the third orthogonal direction. This difference suggests a relationship between levels of orthotropy and bending stress. The comparability of these elastic moduli to those of other vertebrates suggest that the high bone strain magnitudes recorded from the alligator mandible in vivo are not attributable to a lower stiffness of alligator mandibular bone.

  12. Characterization of phospholipase A(2) activity in serum of the American alligator (Alligator mississippiensis).

    PubMed

    Merchant, Mark; Heard, Raphiel; Monroe, Caleb

    2009-11-01

    PLA(2) is a diverse class of enzymes with a broad spectrum of physiological functions. Secretory PLA(2) isoforms have been reported to exhibit important innate immune function in higher vertebrates. This study was conducted to characterize PLA(2) activity in the serum of the American alligator (Alligator mississippiensis). We used a glycerophospholipid with a fatty acid in the sn-2 position labeled with a fluorescent probe (BODIPY) to detect and quantify alligator serum PLA(2) activity. Incubation of BODIPY-labeled bacteria with different concentrations of alligator serum resulted in a concentration-dependent detection of PLA(2) activity. Kinetic studies showed that product formation was rapid, with substantial activity within 5 min, and maximal activity at approximately 20 min. The alligator PLA(2) activity was temperature-dependent, with activity at lower temperatures (5-10 degrees C) approximately half of that observed at temperatures of 30-40 degrees C. In addition, the generation of fluorescent product was reduced by a specific inhibitor (p-bromophenacyl bromide) of secretory PLA(2) in a concentration-dependent manner, enforcing the idea that the observed activities are due to a secretory PLA(2) enzyme in alligator serum.

  13. Ecological studies on the American alligator (Alligator mississippiensis) on the Savannah River Plant

    SciTech Connect

    Seigel, R.A.; Brandt, L.A.; Knight, J.L.; Novak, S.S.

    1986-06-01

    The American alligator (Alligator mississippiensis) is the largest vertebrate of the Savannah River Plant (SRP), reaching a maximum length of 3.7 meters (12 feet) and weighing up to 175 kg (385 pounds). Currently, populations in coastal South Carolina are considered Threatened, whereas populations in inland areas (such as the SRP) are still Endangered. Because of their legal status and economic and ecological importance, it is important to determine the environmental impacts of SRP operations on the local alligator population. The major objectives under the Endangered Species Program of the Comprehensive Cooling Water Study (CCWS) were as follows: (1) document and compare the present status and distribution of alligators on the SRP to previous surveys, in order to determine long-term changes in population abundance; (2) establish baseline population and ecological parameters of the Steel Creek population so that the ecological effects of L-Reactor operations can be determined, and (3) conduct ecological research on the immediate impacts of thermal effluents on American alligators. Gladden et al., (1985) summarized data on previous population surveys, temporal changes in the Par Pond population, preliminary results of the Steel Creek surveys and Savannah River Ecology Laboratory (SREL) research on the effects of thermal effluents. This report summarizes the current status of the SRP population, presents data on the abundance, movement patterns and activity cycles of the Steel Creek population, and presents additional data on the effect of cooling water releases on alligator ecology and behavior.

  14. Survival and growth of American alligator (Alligator mississippiensis) hatchlings after artificial incubation and repatriation

    USGS Publications Warehouse

    Temsiripong, Y.; Woodward, A.R.; Ross, J.P.; Kubilis, P.S.; Percival, H.F.

    2006-01-01

    Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and repatriated hatchlings released within and outside the maternal alligator's home range with naturally incubated hatchlings captured and released within the maternal alligator's home range on Lake Apopka, Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released outside of the maternal alligator's home range had lower recapture probabilities than either naturally incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching. We concluded that repatriation of hatchlings probably would not have long-term effects on populations because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation of older juveniles for population restoration. However, the location of release may affect subsequent survival and growth. Copyright 2006 Society for the Study of Amphibians and Reptiles.

  15. Metabolic responses to chronic hypoxic incubation in embryonic American alligators (Alligator mississippiensis).

    PubMed

    Crossley, Dane A; Ling, Rick; Nelson, Derek; Gillium, Taylor; Conner, Justin; Hapgood, James; Elsey, Ruth M; Eme, John

    2017-01-01

    Chronic hypoxic incubation is a common tool used to study developmental changes in reduced O2 conditions, and it has been useful for identifying phenotypically plastic periods during ontogeny in laboratory settings. Reptilian embryos can be subjected to natural hypoxia due to nesting strategy, and recent studies have been important in establishing the phenotypic responses of several species to low developmental oxygen. In particular, the cardiovascular responses of American alligators (Alligator mississippiensis) to low developmental oxygen have been detailed, including a substantial cardiac enlargement that may support a higher mass specific metabolic rate. However, embryo mass-specific metabolic demands of hypoxic incubated alligator embryos have not been measured. In this study, alligator eggs were incubated in 10% O2 (H) or 21% O2 (N) environments for the entire course of embryonic development. Acute metabolic measures in 21% and 10% O2 were taken for both H and N groups. We hypothesized that acute 10% O2 exposure has no impact on metabolic rate of embryonic alligators, and that metabolic rate is unaffected by chronic hypoxic incubation when studied in embryos measured at 21% O2. Our findings suggest phenotypic changes resulting from hypoxic incubation early in incubation, in particular relative cardiac enlargement, enable embryonic alligators to sustain metabolic rate during acute hypoxic exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Bio-gas production from alligator weeds

    NASA Technical Reports Server (NTRS)

    Latif, A.

    1976-01-01

    Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanthera philoxeroides. Efforts were also made for the isolation and characterization of the methanogenic bacteria.

  17. Crocodiles and Alligators. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    Farre, Marie

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes the physical characteristics, behavior, and peculiar habits of crocodiles, including how to distinguish them from close relatives such as alligators, cayman, and gharials. (YP)

  18. Crocodiles and Alligators. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    Farre, Marie

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes the physical characteristics, behavior, and peculiar habits of crocodiles, including how to distinguish them from close relatives such as alligators, cayman, and gharials. (YP)

  19. Alternathera philoxeroides (Martius) Grisebach - alligator weed

    USDA-ARS?s Scientific Manuscript database

    Biological control of Alternanthera philoxeroides, alligator weed, began when George Vogt, USDA, conducted several surveys by public transport in South America during the 1960s. Three agents were released in USA and two of them, the flea beetle Agasicles hygrophila and the moth Arcola malloi were re...

  20. West Nile Virus in Farmed Alligators

    PubMed Central

    Mauel, Michael J.; Baldwin, Charles; Burtle, Gary; Ingram, Dallas; Hines, Murray E.; Frazier, Kendal S.

    2003-01-01

    Seven alligators were submitted to the Tifton Veterinary Diagnostic and Investigational Laboratory for necropsy during two epizootics in the fall of 2001 and 2002. The alligators were raised in temperature-controlled buildings and fed a diet of horsemeat supplemented with vitamins and minerals. Histologic findings in the juvenile alligators were multiorgan necrosis, heterophilic granulomas, and heterophilic perivasculitis and were most indicative of septicemia or bacteremia. Histologic findings in a hatchling alligator were random foci of necrosis in multiple organs and mononuclear perivascular encephalitis, indicative of a viral cause. West Nile virus was isolated from submissions in 2002. Reverse transcription-polymerase chain reaction (RT-PCR) results on all submitted case samples were positive for West Nile virus for one of four cases associated with the 2001 epizootic and three of three cases associated with the 2002 epizootic. RT-PCR analysis was positive for West Nile virus in the horsemeat collected during the 2002 outbreak but negative in the horsemeat collected after the outbreak. PMID:12890319

  1. Elemental Levels Analyzed by PIXE in Florida Alligators

    NASA Astrophysics Data System (ADS)

    Kuharik, J. C.; Kravchenko, I. I.; Dunnam, F. E.; Van Rinsvelt, H. A.; Ross, J. P.

    2003-08-01

    Unusual and alarming mortality of alligators (Alligator mississippiensis) has been reported from Lake Griffin, Florida, where almost 400 dead alligators have been observed since 1997. In addition, the hatch rate for alligator eggs around Lake Griffin fell below 10% and remains low (30-45%) while the normal hatch rate is typically 80%. Standard diagnostic methods have been ineffective in determining the cause of the phenomenon. Many possibilities have been considered including pollutants, nutrition, and toxic algae. Particle Induced X-ray Emission (PIXE) analysis is highly suitable for investigating concentrations of a wide range of elements in animal tissue. Liver, kidney and spinal cord tissues from healthy and sick alligators have been analyzed by PIXE for elemental content. Initial results showed positive correlation between certain elements and neural impairment and morbidity of alligators in Lake Griffin, but have failed to prove significant.

  2. Elemental Levels Analyzed by PIXE in Florida Alligators

    SciTech Connect

    Kuharik, J.C.; Kravchenko, I.I.; Dunnam, F.E.; Rinsvelt, H.A. van; Ross, J.P.

    2003-08-26

    Unusual and alarming mortality of alligators (Alligator mississippiensis) has been reported from Lake Griffin, Florida, where almost 400 dead alligators have been observed since 1997. In addition, the hatch rate for alligator eggs around Lake Griffin fell below 10% and remains low (30-45%) while the normal hatch rate is typically 80%. Standard diagnostic methods have been ineffective in determining the cause of the phenomenon. Many possibilities have been considered including pollutants, nutrition, and toxic algae. Particle Induced X-ray Emission (PIXE) analysis is highly suitable for investigating concentrations of a wide range of elements in animal tissue. Liver, kidney and spinal cord tissues from healthy and sick alligators have been analyzed by PIXE for elemental content. Initial results showed positive correlation between certain elements and neural impairment and morbidity of alligators in Lake Griffin, but have failed to prove significant.

  3. Levels of mercury in alligators (Alligator mississippiensis) collected along a transect through the Florida Everglades.

    PubMed

    Rumbold, D G; Fink, L E; Laine, K A; Niemczyk, S L; Chandrasekhar, T; Wankel, S D; Kendall, C

    2002-10-07

    As part of a multi-agency study of alligator health, 28 American alligators (Alligator mississippiensis) were captured along a transect through the Florida Everglades in 1999. Liver and tail muscle tissues were sampled and analyzed on a wet weight basis for total mercury (THg) using cold-vapor atomic absorption spectrophotometry. All tissues had detectable concentrations of THg that ranged from 0.6 to 17 mg/kg in liver and from 0.1 to 1.8 mg/kg in tail muscle. THg was more concentrated in liver tissue than tail muscle, but levels were highly correlated between tissues. THg concentrations in tissue differed significantly among locations, with animals from Everglades National Park (ENP) having mean concentrations of THg in liver (10.4 mg/kg) and tail muscle (1.2 mg/kg) that were two-fold higher than basin-wide averages (4.9 and 0.64 mg/kg, respectively). The reasons for higher contamination of ENP alligators were unclear and could not be explained by differences in sex, length, weight or animal age. While delta15N values were positively correlated with THg concentrations in tail muscle, spatial patterns in isotopic composition did not explain the elevated THg levels in ENP alligators. Therefore, it appears that ENP alligators were more highly exposed to mercury in their environment than individuals in other areas. Comparisons to a previous survey by Yanochko et al. [Arch Environ Contam Toxicol 32 (1997) 323] suggest that mercury levels have declined in some Everglades alligators since 1994.

  4. Levels of mercury in alligators (Alligator mississippiensis) collected along a transect through the Florida Everglades

    USGS Publications Warehouse

    Rumbold, D.G.; Fink, L.E.; Laine, K.A.; Niemczyk, S.L.; Chandrasekhar, T.; Wankel, Scott D.; Kendall, C.

    2002-01-01

    As part of a multi-agency study of alligator health, 28 American alligators (Alligator mississippiensis) were captured along a transect through the Florida Everglades in 1999. Liver and tail muscle tissues were sampled and analyzed on a wet weight basis for total mercury (THg) using cold-vapor atomic absorption spectrophotometry. All tissues had detectable concentrations of THg that ranged from 0.6 to 17 mg/kg in liver and from 0.1 to 1.8 mg/kg in tail muscle. THg was more concentrated in liver tissue than tail muscle, but levels were highly correlated between tissues. THg concentrations in tissue differed significantly among locations, with animals from Everglades National Park (ENP) having mean concentrations of THg in liver (10.4 mg/kg) and tail muscle (1.2 mg/kg) that were two-fold higher than basin-wide averages (4.9 and 0.64 mg/kg, respectively). The reasons for higher contamination of ENP alligators were unclear and could not be explained by differences in sex, length, weight or animal age. While ??15N values were positively correlated with THg concentrations in tail muscle, spatial patterns in isotopic composition did not explain the elevated THg levels in ENP alligators. Therefore, it appears that ENP alligators were more highly exposed to mercury in their environment than individuals in other areas. Comparisons to a previous survey by Yanochko et al. [Arch Environ Contam Toxicol 32 (1997) 323] suggest that mercury levels have declined in some Everglades alligators since 1994. ?? 2002 Elsevier Science B.V. All rights reserved.

  5. Intraocular pressure variation associated with body length in young American alligators (Alligator mississippiensis).

    PubMed

    Whittaker, C J; Heaton-Jones, T G; Kubilis, P S; Smith, P J; Brooks, D E; Kosarek, C; Mackay, E O; Gelatt, K N

    1995-10-01

    Using an applanation tonometer, 5 replicate intraocular pressure (IOP) measurements were obtained from each eye of 12 young clinically normal, American alligators. Alligator length ranged from 46 to 117 cm, measured from snout to tail tip. All IOP were recorded by a single observer at an ambient temperature of approximately 25 C, and ranged from 5 to 35 mm of Hg. Observer reliability was excellent (intraclass r = 0.93), and IOP did not change over the ordered sequence of 5 replicate measurements/eye. Replicate IOP) measurements were, therefore, averaged in each eye for comparison between eyes of the same alligator. Left and right eve IOP were highly correlated within individual alligators (r = 0.92), whereas the mean within animal difference between left and right eye IOP was not statistically significant (95% confidence interval [CI] for the left eye-right eye mean difference, - 1.9 to 1.3 min of Hg). Mean IOP determined for 5 confirmed females and 3 confirmed males did not differ significantly between the sexes (95% CI for the male-female difference in means, -2.1 to 3.7 mm of Hg). Mean +/- SEM IOP of 23.7 + 2.1 mm of Hg determined for 4 alligators < -50 cm long was significantly (P = 0.009) greater than mean IOP of 11.6 + 0.5 mm of Hg determined for 8 alligators > 50 cm long (95% CI for the difference in means, 8.5 to 15.7 mm of Hg). In young alligators, the relation between body length and IOP appears to be nonlinear, possibly with a negative exponent.

  6. Gizzard shad thiaminase activity and its effect on the thiamine status of captive American alligators Alligator mississippiensis.

    PubMed

    Ross, J Perran; Honeyfield, Dale C; Brown, Scott B; Brown, Lisa R; Waddle, Amanda Rice; Welker, Michael E; Schoeb, Trenton R

    2009-12-01

    Adult mortality and low egg hatch rate were observed among American alligators Alligator mississippiensis in Lake Griffin, Florida, between 1998 and 2003. Previous studies show that the alligator mortality is due to neurological impairment associated with thiamine (vitamin Bt) deficiency. This study determined the rate of thiaminase activity in gizzard shad Dorosoma cepedianum, a fish often eaten by alligators, and examined the thiamine status of captive adult alligators fed only gizzard shad. We found that the thiaminase activity of gizzard shad in Lake Griffin is 16,409 +/- 2,121 pmol/g/min (mean +/- 2SEs). This high rate of thiaminase activity was present in most months and across a wide range of shad sizes. Seven alligators were captured in the wild from Lake Griffin and Lake Woodruff, held in captivity, and fed gizzard shad. We monitored blood and muscle thiamine levels throughout the experiment and liver thiamine at the end. Over a period of 6-12 months, all of the alligators maintained weight but blood and muscle thiamine levels decreased to 25-50% of the original (healthy) values. Three animals with the greatest reduction in thiamine died, demonstrating mobility impairment and neural histopathology similar to those seen in wild alligators in Lake Griffin. Two alligators were fed shad for 10 months but then treated with thiamine. These animals showed a reduction in thiamine while eating shad, but treatment restored their thiamine levels to the initial values, which were comparable to those of normal wild Lake Griffin alligators. We demonstrated that thiamine deficiency can be induced by a diet of gizzard shad and cause neurological signs and death in alligators in captivity. We conclude that the thiaminase activity in gizzard shad is high enough to cause thiamine deficiency in wild alligators when shad are a major part of their diet.

  7. Exhaustive exercise training enhances aerobic capacity in American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Owerkowicz, Tomasz; Gwalthney, June; Blank, Jason M; Rourke, Bryan C; Hicks, James W

    2009-11-01

    The oxygen transport system in mammals is extensively remodelled in response to repeated bouts of activity, but many reptiles appear to be 'metabolically inflexible' in response to exercise training. A recent report showed that estuarine crocodiles (Crocodylus porosus) increase their maximum metabolic rate in response to exhaustive treadmill training, and in the present study, we confirm this response in another crocodilian, American alligator (Alligator mississippiensis). We further specify the nature of the crocodilian training response by analysing effects of training on aerobic [citrate synthase (CS)] and anaerobic [lactate dehydrogenase (LDH)] enzyme activities in selected skeletal muscles, ventricular and skeletal muscle masses and haematocrit. Compared to sedentary control animals, alligators regularly trained for 15 months on a treadmill (run group) or in a flume (swim group) exhibited peak oxygen consumption rates higher by 27 and 16%, respectively. Run and swim exercise training significantly increased ventricular mass (~11%) and haematocrit (~11%), but not the mass of skeletal muscles. However, exercise training did not alter CS or LDH activities of skeletal muscles. Similar to mammals, alligators respond to exercise training by increasing convective oxygen transport mechanisms, specifically heart size (potentially greater stroke volume) and haematocrit (increased oxygen carrying-capacity of the blood). Unlike mammals, but similar to squamate reptiles, alligators do not also increase citrate synthase activity of the skeletal muscles in response to exercise.

  8. Production of superoxide ions by leukocytes of the American alligator (Alligator mississippiensis).

    PubMed

    Merchant, Mark; Williams, Stetson; Hardy, Ross

    2009-01-01

    This study was conducted to characterize the production of superoxide ions by leukocytes in whole blood of the American alligator (Alligator mississippiensis). We used WST-1, a tetrazolium salt which can be reduced to a water-soluble formazan compound with high molar absorptivity at 438 nm, to probe the production of superoxide by alligator leukocytes. Incubation of alligator whole blood with WST-1 resulted in a time- and concentration-dependent increase in absorbance of the plasma at 438 nm. The reduction of WST-1 was inhibited in a concentration-dependent manner by superoxide dismutase, an enzyme that catalyzes the reduction of superoxide to peroxide, confirming that the reduction of WST-1 was due to the presence of superoxide. Treatment of whole blood with nitrotetrazolium blue (NBT) resulted in the staining of heterophils and monocytes, enforcing the idea that that the production of superoxide is due to the presence of leukocytes, and not other blood cell components. It is interesting to note that the production of superoxide by the alligator leukocytes required no external stimulation while human leukocytes must be stimulated with an immunological challenge before producing superoxide. This is the first report of the production of superoxide as an innate immune mechanism in crocodilians.

  9. Age- and gender-related accumulation of perfluoroalkyl substances in captive Chinese alligators (Alligator sinensis).

    PubMed

    Wang, Jianshe; Zhang, Yating; Zhang, Fang; Yeung, Leo W Y; Taniyasu, Sachi; Yamazaki, Eriko; Wang, Renping; Lam, Paul K S; Yamashita, Nobuyoshi; Dai, Jiayin

    2013-08-01

    Fourteen perfluoroalkyl substances (PFASs) were measured in serum of the highly endangered captive Chinese alligators, whole body homogenates of six kinds of fish (alligator prey species), and pond water (alligator habitat) in the Anhui Research Center for Chinese Alligator Reproduction. Six PFASs, including PFOS and five perfluorinated carboxylates, were detected in all alligator samples. The most dominant PFAS was PFUnDA, with a mean value of 31.4 ng/mL. Significant positive correlations were observed among the six PFASs, suggesting that they shared similar sources of contamination. Significantly higher PFOS and PFUnDA levels were observed in males, but the other four PFCAs did not differ between genders. An age related PFAS bioaccumulation analysis showed a significant negative correlation of the concentrations for five PFCAs to age, which means that higher concentrations were found in younger animals. Bioaccumulation factors (BAF) in fish for PFASs ranged from 21 to 28,000, with lower BAF for PFOA than that for longer carbon chain PFCAs, including PFUnDA, PFDA, and PFNA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. INTRAMUSCULAR EPINEPHRINE RESULTS IN REDUCED ANESTHETIC RECOVERY TIME IN AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) UNDERGOING ISOFLURANE ANESTHESIA.

    PubMed

    Gatson, Bonnie J; Goe, Alexandra; Granone, Tiffany D; Wellehan, James F X

    2017-03-01

    Inhalants are commonly used to anesthetize reptiles, but volatile anesthetics have been associated with prolonged recovery times. The objective of this study was to determine the effects of intramuscular (IM) epinephrine on anesthetic recovery times following isoflurane anesthesia in a population of subadult American alligators ( Alligator mississippiensis ). In this prospective randomized crossover study, five clinically healthy alligators were anesthetized for 90 min with the use of isoflurane. Alligators were randomly assigned into one of two treatment groups: Group E received IM epinephrine (0.1 mg/kg), and Group S received an equal volume of 0.9% saline administered after isoflurane was discontinued. Time from the end of inhalant administration to return of spontaneous ventilation, return of the palpebral reflex, movement in response to a standardized toe pinch, and spontaneous movement was recorded. The time of extubation was noted and occurred following the return of spontaneous ventilation and movement. Pulse rate, surface body temperature, and airway gases including expiratory and inspiratory isoflurane concentrations and end-tidal carbon dioxide were measured every 5 min throughout the study. The time from the end of anesthesia to extubation was significantly faster in Group E (51.2 ± 16.7 min) compared to Group S (107.4 ± 43.7 min). Pulse rate was significantly higher within the first 15 min following epinephrine injection compared to the saline group at these time points. Therefore, IM epinephrine administered at the end of general anesthesia can significantly hasten anesthetic recovery from isoflurane in alligators.

  11. Salmonella Enterica Serovar Pomona Infection in Farmed Juvenile American Alligators ( Alligator Mississippiensis).

    PubMed

    Sakaguchi, K; Nevarez, J G; Del Piero, F

    2017-03-01

    A fatal epizootic of salmonellosis occurred in farmed juvenile American alligators in Louisiana. Six animals were examined. Gross lesions included severe fibrinonecrotizing enterocolitis, necrotizing splenitis, coelomic effusion, and perivisceral and pulmonary edema. Microscopic examination revealed severe necrotizing enterocolitis and splenitis with intralesional bacteria and pneumocyte necrosis with fibrin thrombi. Salmonella enterica serovar Pomona was isolated from intestine and lung. Clinical salmonellosis is a rare finding in reptiles and salmonellosis caused by S. Pomona is not previously reported in American alligators. Since S. Pomona is a commonly isolated Salmonella serotype from patients with reptile-associated salmonellosis in the United States, and since alligator meat is consumed and the skin is exported to numerous countries, risk of human and animal infection should be considered.

  12. Pharmacokinetics of tetracycline after single-dose oral administration in the American alligator (Alligator mississippiensis).

    PubMed

    Rivera, Sam; Nevarez, Javier G; Maxwell, Lara K; Barker, Steven A

    2012-12-01

    The major objective of the study was to assess the pharmacokinetics of tetracycline administered orally to fasted and nonfasted American alligators (Alligator mississippiensis) at 50 mg/kg. Plasma levels of tetracycline were determined using high-performance liquid chromatography with ultraviolet detection. The concentration versus time curve was analyzed using a compartmental modeling technique. A one-compartment model with first-order absorption and elimination, as well as a lag time to absorption, best described the data. The area under the curve and mean residence time values differed significantly between the fasted and nonfasted groups. Based on the results of this study, tetracycline suspension administered once orally at 50 mg/kg to American alligators is not expected to reach plasma concentrations above the breakpoint minimum inhibitory concentration of 4 microg/ml for susceptible organisms.

  13. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  14. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  15. Developmental effects of embryonic exposure to toxaphene in the American alligator (Alligator mississippiensis).

    PubMed

    Milnes, Matthew R; Allen, Davina; Bryan, Teresa A; Sedacca, Cassidy D; Guillette, Louis J

    2004-05-01

    A variety of organochlorine pesticides have been shown to adversely affect embryonic development. A number of abnormalities have been documented in alligators (Alligator mississippiensis) from highly-contaminated Lake Apopka, FL, USA that are similar to the results of experimental studies exposing embryos to pesticides. In the current study, we exposed developing alligator embryos to varying concentrations of toxaphene, a broad-spectrum pesticide found in relatively high concentration in Lake Apopka alligator egg yolk. The toxaphene, dissolved in 50 microl of ethanol, was applied topically to the eggshell just prior to the sex-determining period of development. Shortly after hatching, we examined a number of morphological and physiological endpoints to determine the consequences of sub-lethal embryonic exposure to toxaphene. Our results indicate that toxaphene had little or no effect on the morphological endpoints examined including body mass (BM) and size, liver, thyroid, and gonad development. In addition, toxaphene failed to affect sexual differentiation, or in vitro thyroxin, testosterone (T), and estradiol production. However, male plasma T concentration was higher in animals treated with 10 and 0.01 microg toxaphene/kg (based on mean egg mass) than control males. Because in vitro T production was not different among control groups, we suggest the difference in plasma T could be due to differences in hypothalamic-pituitary stimulation of the gonad or hepatic steroid degradation. This study indicates that technical grade toxaphene, at the applied doses, does not induce the same developmental abnormalities associated with alligators living in Lake Apopka. Future studies should consider the effects of embryonic exposure to a mixture of chemicals, including toxaphene metabolites, on development in alligators to better evaluate the consequences of environmental contamination.

  16. In vitro drug susceptibility pattern of Mycoplasma alligatoris isolated from symptomatic American alligators (Alligator mississippiensis).

    PubMed

    Helmick, Kelly E; Brown, Daniel R; Jacobson, Elliott R; Brown, Mary B

    2002-06-01

    A recently described mycoplasma, Mycoplasma alligatoris, was isolated from dead American alligators (Alligator mississippiensis) that had demonstrated clinical signs of lethargy, anorexia, bilateral ocular discharge, edema. paraparesis, and polyarthritis. The in vitro minimum inhibitory concentration for nine antibacterial agents was determined through serial dilution in broth and plate culture for M. alligatoris isolates. The inhibitory concentration obtained for doxycycline, enrofloxacin, sarafloxacin, oxytetracycline, tilmicosin, and tylosin (< 1 microg/ml) was lower than that of clindamycin (1-8 microg/ml), chloramphenicol (8-16 microg/ml), and erythromycin (32-138 microg/ml).

  17. HISTOPATHOLOGY OF GASTRIC WALL IN CHINESE ALLIGATOR ALLIGATOR SINENSIS INFECTED WITH ORTLEPPASCARIS SINENSIS (NEMATODA: ASCARIDOIDEA).

    PubMed

    Zhao, Jinhong; Wang, Shaosheng; Tu, Genjun; Zhou, Yongkang; Wu, Xiaobing; Li, Chaopin

    2015-09-01

    Crocodiles are susceptible to infection with a wide array of external and internal gastrointestinal helminths, yet little is known on the histopathology following infection or the effects of these parasites. The present study was aimed at evaluating the impact of infection by Ortleppascaris sinensis (Nematoda: Ascaridoidea) on the stomach of captive Alligator sinensis. The histological examination of the stomach revealed presence of superficial ulcer in mucous layer and granulomatous inflammation in submucous layer at entire gastric walls of the Alligator sinensis. Our findings also confirm that development of Ortleppascaris sinensis is in close association with the wall of the stomach. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  18. Tissue mercury concentrations in alligators (Alligator mississippiensis) from the Florida Everglades and the Savannah River Site, South Carolina.

    PubMed

    Yanochko, G M; Jagoe, C H; Brisbin, I L

    1997-04-01

    Mercury pollution is a serious problem in some areas of the southeastern United States. Due to biomagnification, long-lived predators should have high Hg concentrations in affected areas. American alligators(Alligator mississippiensis) are important predators in many southwestern wetlands, but little information is available on Hg concentrations in this species. We collected tissues from alligators inhabiting two sites in the Everglades, Florida (n = 18) and a manmade reservoir in South Carolina (Par Pond; n = 44), all with documented histories of Hg contamination, and analyzed them for total Hg. Mean concentrations in kidney, liver, muscle, and dermal scutes of alligators from the Everglades (expressed as mg Hg/kg dry mass +/- S.E.M.) were 36.42 +/- 5.23, 41.09 +/- 5.90, 5.57 +/- 0.47, and 5.83 +/- 1.04, respectively. Concentrations in liver, muscle, and scutes from Par Pond alligators were 17.73 +/- 2.56, 4.08 +/- 0.46, and 4.58 +/- 0.63,respectively. Blood from Par Pond alligators contained 2.20 +/- 0.38 mg Hg/kg wet mass. Mercury concentrations did not differ among sexes at any location. Tissue Hg levels did not differ significantly between Everglades locations,but were lower in Par Pond. In Everglades alligators, Hg concentrations in all tissues were positively correlated, as were tissue Hg and total length. Only total length and scute Hg were correlated in Par Pond alligators. Regression revealed a significant relationship between muscle and scute Hg concentrations in Everglades alligators, but not Par Pond alligators. Alligators living in polluted areas can accumulate substantial concentrations of Hg, but relationships among Hg concentrations in specific tissues may vary with location or age and size of the animals sampled.

  19. Gonadotropin-induced testosterone response in peripubertal male alligators.

    PubMed

    Edwards, Thea M; Gunderson, Mark P; Milnes, Matthew R; Guillette, Louis J

    2004-02-01

    Based on the response to three different gonadotropin challenges, we evaluated seasonal production of testosterone in a group of captive-raised four-year-old male alligators that varied in size. To stimulate gonadal steroidogenesis, we injected each alligator with ovine FSH (150 ng/ml plasma). Plasma testosterone concentrations were measured in repeated blood samples taken between 0 and 72 h after FSH injection. To determine if there was seasonal variation in response, we repeated the experiment on the same alligators three times during the breeding season (March, May, and July, 2000). All alligators responded to exogenous FSH by exhibiting increased plasma concentrations of testosterone (p < 0.0001 for all months). However, the degree of the response depended on body size. Thus, larger alligators produced more testosterone and were more affected by changes in season compared to smaller alligators. We have previously observed that juvenile male alligators display seasonal changes in plasma testosterone concentrations that mimic the cycle observed in adult males. Our present data suggest that seasonal changes in plasma testosterone appear to be associated not only with changes in gonadotropin release but in gonadal responsiveness as well. We propose, given these observations, that alligators experience an extended period of puberty, during which the gonads synthesize gradually increasing steroid hormone concentrations. These peripubertal animals are not juveniles but sub-adults capable of responding to the seasonal signals associated with reproductive timing in adults.

  20. Incubation history prior to the canonical thermosensitive period determines sex in the American alligator.

    PubMed

    McCoy, Jessica A; Parrott, Benjamin B; Rainwater, Thomas R; Wilkinson, Phillip M; Guillette, Louis J

    2015-10-01

    Despite the widespread occurrence of environmental sex determination (ESD) among vertebrates, our knowledge of the temporal dynamics by which environmental factors act on this process remains limited. In many reptiles, incubation temperature determines sex during a discrete developmental window just prior to and coincident with the differentiation of the gonads. Yet, there is substantial variation in sex ratios among different clutches of eggs incubated at identical temperatures during this period. Here, we test the hypothesis that temperatures experienced prior to the reported thermosensitive period for alligators (Alligator mississippiensis) can impact how the sex determination system responds to thermal cues later in development. Temperature shift experiments on eggs collected from the field within 24  h of oviposition were employed to decouple various maternal influences from thermal effects, and results demonstrate a previously undefined window of thermosensitivity occurring by stage 15 of embryonic development, six stages earlier than previously reported. We also examine the intrasexual expression of several male- and female-biased genes and show that while male-biased genes display no intrasexual differences, ovarian CYP19A1 (aromatase) transcript abundance differs by approximately twofold depending on thermal exposures experienced at early stages of embryonic development. These findings expand our understanding of the ESD in the alligator and provide the rationale for reevaluation of the temporal dynamics of sex determination in other crocodilians.

  1. Hexavalent Chromium Is Cytotoxic and Genotoxic to American Alligator Cells

    PubMed Central

    Wise, Sandra S.; Wise, Catherine; Xie, Hong; Guillette, Louis J.; Zhu, Cairong; Wise, John Pierce; Wise, John Pierce

    2016-01-01

    Metals are a common pollutant in the aquatic ecosystem. With global climate change, these levels are anticipated to rise as lower pH levels allow sediment bound metals to be released. The American alligator (Alligator mississippiensis) is an apex predator in the aquatic ecosystem and is considered a keystone species; as such it serves as a suitable monitor for localized pollution. One metal of increasing concern is hexavalent chromium (Cr(VI)). It is present in the aquatic environment and is a known human carcinogen and reproductive toxicant. We measured the cytotoxicity and genotoxicity of Cr(VI) in American alligator cells derived from scute tissue. We found that particulate and soluble Cr(VI) are both cytotoxic and genotoxic to alligator cells in a concentration-dependent manner. These data suggest that alligators may be used as a model for assessing the effects of environmental Cr(VI) contamination as well as for other metals of concern. PMID:26730726

  2. Pathology, physiologic parameters, tissue contaminants, and tissue thiamine in morbid and healthy central Florida adult American alligators (Alligator mississippiensis)

    USGS Publications Warehouse

    Honeyfield, D.C.; Ross, J.P.; Carbonneau, D.A.; Terrell, S.P.; Woodward, A.R.; Schoeb, T.R.; Perceval, H.F.; Hinterkopf, J.P.

    2008-01-01

    An investigation of adult alligator (Alligator mississippiensis) mortalities in Lake Griffin, central Florida, was conducted from 1998-2004. Alligator mortality was highest in the months of April and May and annual death count peaked in 2000. Bacterial pathogens, heavy metals, and pesticides were not linked with the mortalities. Blood chemistry did not point to any clinical diagnosis, although differences between impaired and normal animals were noted. Captured alligators with signs of neurologic impairment displayed unresponsive and uncoordinated behavior. Three of 21 impaired Lake Griffin alligators were found to have neural lesions characteristic of thiamine deficiency in the telencephalon, particularly the dorsal ventricular ridge. In some cases, lesions were found in the thalamus, and parts of the midbrain. Liver and muscle tissue concentrations of thiamine (vitamin B"1) were lowest in impaired Lake Griffin alligators when compared to unimpaired alligators or to alligators from Lake Woodruff. The consumption of thiaminase-positive gizzard shad (Dorosoma cepedianum) is thought to have been the cause of the low tissue thiamine and resulting mortalities. ?? Wildlife Disease Association 2008.

  3. Heavy metal and selenium concentrations in liver tissue from wild American alligator (Alligator mississippiensis) livers near Charleston, South Carolina.

    PubMed

    Campbell, Joshua W; Waters, Matthew N; Tarter, Anna; Jackson, Jennifer

    2010-10-01

    Liver samples from 33 wild American alligators (Alligator mississippiensis) livers from the Charleston, South Carolina, area were analyzed for arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb), and selenium (Se) concentrations. Alligators are top predators and are considered a good biomonitoring species for various toxins, including heavy metals. Alligators from other areas in the US have shown high concentrations of mercury and other heavy metals, but the Charleston area, which is highly industrialized, has not been investigated. We found wide variation in hepatic heavy metal and selenium concentrations among alligators. Length and sex did not show a strong relationship with any metal based on statistical analysis. However, cluster analysis revealed three groupings of alligators based on liver metal concentrations. Alligators with low Se:Hg ratios also had high concentrations of Hg. Due to the wide variation in metal concentrations among individual alligators, we postulate that individual diet and microhabitat usage could be the cause for this variation.

  4. Pathology, physiologic parameters, tissue contaminants, and tissue thiamine in morbid and healthy central Florida adult American alligators (Alligator mississippiensis).

    PubMed

    Honeyfield, Dale C; Ross, J Perran; Carbonneau, Dwayne A; Terrell, Scott P; Woodward, Allan R; Schoeb, Trenton R; Perceval, H Franklin; Hinterkopf, Joy P

    2008-04-01

    An investigation of adult alligator (Alligator mississippiensis) mortalities in Lake Griffin, central Florida, was conducted from 1998-2004. Alligator mortality was highest in the months of April and May and annual death count peaked in 2000. Bacterial pathogens, heavy metals, and pesticides were not linked with the mortalities. Blood chemistry did not point to any clinical diagnosis, although differences between impaired and normal animals were noted. Captured alligators with signs of neurologic impairment displayed unresponsive and uncoordinated behavior. Three of 21 impaired Lake Griffin alligators were found to have neural lesions characteristic of thiamine deficiency in the telencephalon, particularly the dorsal ventricular ridge. In some cases, lesions were found in the thalamus, and parts of the midbrain. Liver and muscle tissue concentrations of thiamine (vitamin B(1)) were lowest in impaired Lake Griffin alligators when compared to unimpaired alligators or to alligators from Lake Woodruff. The consumption of thiaminase-positive gizzard shad (Dorosoma cepedianum) is thought to have been the cause of the low tissue thiamine and resulting mortalities.

  5. Perfluorinated Alkyl Acids in Plasma of American Alligators (Alligator Mississippiensis) from Florida and South Carolina

    NASA Technical Reports Server (NTRS)

    Bangma, Jacqueline T.; Bowden, John A.; Brunell, Arnold M.; Christie, Ian; Finnell, Brendan; Guillette, Matthew P.; Jones, Martin; Lowers, Russell H.; Rainwater, Thomas R.; Reiner, Jessica L.; hide

    2016-01-01

    This study aimed to quantitate fourteen perfluoroalkyl acids (PFAAs) in 125 adult American alligators at twelve sites across the southeastern US. Of those fourteen PFAAs, nine were detected in 65% - 100% of the samples: PFOA, PFNA, PFDA, PFUnA, PFDoA, PFTriA, PFTA, PFHxS, and PFOS. Males (across all sites) showed significantly higher concentrations of four PFAAs: PFOS (p = 0.01), PFDA (p = 0.0003), PFUnA (p = 0.021), and PFTriA (p = 0.021). Concentrations of PFOS, PFHxS, and PFDA in plasma were significantly different among the sites in each sex. Alligators at Merritt Island National Wildlife Refuge and Kiawah Nature Conservancy both exhibited some of the highest PFOS concentrations (medians 99.5 ng/g and 55.8 ng/g respectively) in plasma measured to date in a crocodilian species. A number of positive correlations between PFAAs and snout-vent length (SVL) were observed in both sexes suggesting PFAA body burdens increase with increasing size. In addition, several significant correlations among PFAAs in alligator plasma may suggest conserved sources of PFAAs at each site throughout the greater study area. This study is the first to report PFAAs in American alligators, reveals potential PFAA hot spots in Florida and South Carolina, and provides and additional contaminant of concern when assessing anthropogenic impacts on ecosystem health.

  6. Seasonal variation of the oviduct of the American alligator, Alligator mississippiensis (Reptilia: Crocodylia).

    PubMed

    Bagwill, April; Sever, David M; Elsey, Ruth M

    2009-06-01

    The annual oviductal cycle of the American alligator, Alligator mississippiensis, is described using light and electron microscopy. Previous work done by Palmer and Guillette ([1992] Biol Reprod 46:39-47) shed some light on the reproductive morphology of the female alligator oviduct; however, their study was limited and did not report details relating to variation across the reproductive season. We recognize six variable regions of the oviduct: infundibulum, tube, isthmus, anterior uterus, posterior uterus, and vagina. Each area shows variation, to some degree, in the histochemistry and ultrastructure of oviductal secretions. Peak secretory activity occurs during the months of May and June, with the greatest variation occurring in the tube and anterior uterus. During the month of May, high densities of neutral carbohydrates and proteins are found within the tubal and anterior uterine glands. The epithelium of the entire oviduct secretes neutral carbohydrates throughout the year, but many regions lack protein secretions, and the posterior uterine glands show little secretory activity of any type throughout the year. After oviposition, secretory activity decreases drastically, andthe oviduct resembles that of the premating season. This study also provides evidence to support the homology between alligator and bird oviducts. Sperm were observed in glands at the tubal-isthmus and utero-vaginal junctions in preovulatory, postovulatory and postovipository females.

  7. Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis).

    PubMed

    Nilsen, Frances M; Parrott, Benjamin B; Bowden, John A; Kassim, Brittany L; Somerville, Stephen E; Bryan, Teresa A; Bryan, Colleen E; Lange, Ted R; Delaney, J Patrick; Brunell, Arnold M; Long, Stephen E; Guillette, Louis J

    2016-03-01

    Mercury is a widespread environmental contaminant with exposures eliciting a well-documented catalog of adverse effects. Yet, knowledge regarding the underlying mechanisms by which mercury exposures are translated into biological effects remains incomplete. DNA methylation is an epigenetic modification that is sensitive to environmental cues, and alterations in DNA methylation at the global level are associated with a variety of diseases. Using a liquid chromatography tandem mass spectrometry-based (LC-MS/MS) approach, global DNA methylation levels were measured in red blood cells of 144 wild American alligators (Alligator mississippiensis) from 6 sites with variable levels of mercury contamination across Florida's north-south axis. Variation in mercury concentrations measured in whole blood was highly associated with location, allowing the comparison of global DNA methylation levels across different "treatments" of mercury. Global DNA methylation in alligators across all locations was weakly associated with increased mercury exposure. However, a much more robust relationship was observed in those animals sampled from locations more highly contaminated with mercury. Also, similar to other vertebrates, global DNA methylation appears to decline with age in alligators. The relationship between age-associated loss of global DNA methylation and varying mercury exposures was examined to reveal a potential interaction. These findings demonstrate that global DNA methylation levels are associated with mercury exposure, and give insights into interactions between contaminants, aging, and epigenetics.

  8. West Nile virus infection in farmed American alligators (Alligator mississippiensis) in Florida.

    PubMed

    Jacobson, Elliott R; Ginn, Pamela E; Troutman, J Mitchell; Farina, Lisa; Stark, Lillian; Klenk, Kaci; Burkhalter, Kristen L; Komar, Nicholas

    2005-01-01

    In September and October 2002, an epizootic of neurologic disease occurred at an alligator farm in Florida (USA). Three affected American alligators (Alligator mississippiensis) were euthanatized and necropsied, and results confirmed infection with West Nile virus (WNV). The most significant microscopic lesions were a moderate heterophilic to lymphoplasmacytic meningoencephalomyelitis, necrotizing hepatitis and splenitis, pancreatic necrosis, myocardial degeneration with necrosis, mild interstitial pneumonia, heterophilic necrotizing stomatitis, and glossitis. Immunohistochemistry identified WNV antigen, with the most intense staining in liver, pancreas, spleen, and brain. Virus isolation and RNA detection by reverse transcription-polymerase chain reaction confirmed WNV infection in plasma and tissue samples. Of the tissues, liver had the highest viral loads (maximum 10(8.9) plaque-forming units [PFU]/0.5 cm3), whereas brain and spinal cord had the lowest viral loads (maximum 10(6.6) PFU/0.5 cm3 each). Virus titers in plasma ranged from 10(3.6) to 10(6.5) PFU/ml, exceeding the threshold needed to infect Culex quinquefasciatus mosquitoes (10(5) PFU/ml). Thus, alligators may serve as a vertebrate amplifying host for WNV.

  9. Morphogenesis and patterning of the phallus and cloaca in the American alligator, alligator mississippiensis.

    PubMed

    Gredler, Marissa L; Seifert, Ashley W; Cohn, Martin J

    2015-01-01

    In most animals, reproduction by internal fertilization is facilitated by an intromittent organ, such as the penis in amniote vertebrates. Recent progress has begun to uncover the mechanisms of mammalian external genital development; however, comparatively little is known about the development of the reptilian penis and clitoris. Here, we describe the development of the phallus and cloaca in the American alligator, Alligator mississippiensis. The embryonic precursor of the penis and clitoris is the genital tubercle, which forms by the budding of genital mesenchyme beneath the ventral body wall ectoderm, adjacent to the cloacal membrane. The cloacal lips develop from another pair of outgrowths, the lateral swellings. Early development of the alligator phallus, cloaca, and urogenital ducts generally resembles that of other reptiles, suggesting that differences in adult reptilian phallus and cloacal anatomy arise at later stages. The phallic sulcus is derived from the cloacal endoderm, indicating that the crocodilian sulcus is functionally and developmentally homologous to the mammalian urethra. Initial external genital outgrowth and patterning occur prior to temperature-dependent sex determination. Our analysis of alligator phallus and cloaca development suggests that modifications of an ancestral program of urogenital development could have generated the morphological diversity found in the external genitalia of modern amniotes.

  10. Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis)

    PubMed Central

    Nilsen, Frances M.; Parrott, Benjamin B.; Bowden, John A.; Kassim, Brittany L.; Somerville, Stephen E.; Bryan, Teresa A.; Bryan, Colleen E.; Lange, Ted R.; Delaney, J. Patrick; Brunell, Arnold M.; Long, Stephen E.; Guillette, Louis J.

    2016-01-01

    Mercury is a widespread environmental contaminant with exposures eliciting a well-documented catalog of adverse effects. Yet, knowledge regarding the underlying mechanisms by which mercury exposures are translated into biological effects remains incomplete. DNA methylation is an epigenetic modification that is sensitive to environmental cues, and alterations in DNA methylation at the global level are associated with a variety of diseases. Using a liquid chromatography tandem mass spectrometry-based (LC-MS/MS) approach, global DNA methylation levels were measured in red blood cells of 144 wild American alligators (Alligator mississippiensis) from 6 sites with variable levels of mercury contamination across Florida’s north-south axis. Variation in mercury concentrations measured in whole blood was highly associated with location, allowing the comparison of global DNA methylation levels across different “treatments” of mercury. Global DNA methylation in alligators across all locations was weakly associated with increased mercury exposure. However, a much more robust relationship was observed in those animals sampled from locations more highly contaminated with mercury. Also, similar to other vertebrates, global DNA methylation appears to decline with age in alligators. The relationship between age-associated loss of global DNA methylation and varying mercury exposures was examined to reveal a potential interaction. These findings demonstrate that global DNA methylation levels are associated with mercury exposure, and give insights into interactions between contaminants, aging, and epigenetics. PMID:26748003

  11. Persistent halogenated compounds in captive Chinese alligators (Alligator sinensis) from China.

    PubMed

    Wu, Ting; Hong, Bing; Wu, Xiaobing; Wu, Jiangping; Wang, Xinming; Yi, Zhigang; Zhao, Juan; Zhan, Miao; Mai, Bixian

    2014-09-01

    While a number of studies have reported residual levels of persistent halogenated compounds (PHCs) in crocodilia, there is still a dearth of information on the Chinese alligator, a critically endangered crocodilian species. In the present study, several PHCs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane and its metabolites (DDTs), were detected in the adult tissues, neonates, and eggs of captive Chinese alligators from China. The concentrations of ΣPBDEs, ΣPCBs, and ΣDDTs in Chinese alligators ranged from 0.11 to 16.1, 1.12 to 22.2, and 6.03 to 1020ngg(-1) wet weight, respectively, with higher levels of ΣPCBs and ΣDDTs in the neonates and eggs than in muscle tissues. The ΣDDT residues in the studied Chinese alligators were at the high end of reported ranges from crocodilia around the world, and some results exceeded levels known to cause a female-biased sex ratio in crocodilians. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Polychlorinated biphenyls in eggs and chlorioallantoic membranes of American alligators (Alligator mississippiensis) from coastal South Carolina

    SciTech Connect

    Cobb, G.P.; Wood, P.D.; O`Quinn, M.

    1997-07-01

    Assessing chemical exposure in threatened or endangered wildlife species presents unique analytical problems. Chorioallantoic membranes (CAMs) have been proposed as surrogate tissues for evaluation of polychlorinated biphenyl (PCB) exposure in oviparous species. Research was undertaken to determine the extent of PCB accumulation in alligators (Alligator mississippiensis) at sites along the coast of South Carolina and to evaluate the utility of CAMs as surrogate tissues for determining PCB concentrations in whole alligator eggs. Polychlorinated biphenyls were found in eggs and CAMs of alligators from both sites examined. Concentrations of PCBs were higher in CAMs (p = 0.02) and eggs (p = 0.001) from sites known to contain chlorinated hydrocarbons than from more pristine sites. Total PCBs partitioned predictably (r{sup 2} > 0.59; p < 0.02) between egg and CAM tissues indicating the utility of CAMs to serve as surrogate tissues when comparing total PCB concentrations in whole eggs. Tetrachloro through octachloro biphenyl homologues and total PCBs in CAMs from reference areas were correlated with concentrations of these homologues in eggs. At contaminated sites, total PCB concentrations in CAMs were correlated with total PCB concentrations in eggs.

  13. Fluctuating water depths affect American alligator (Alligator mississippiensis) body condition in the Everglades, Florida, USA

    USGS Publications Warehouse

    Brandt, Laura A.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Cherkiss, Michael S.; Mazzotti, Frank J.

    2016-01-01

    Successful restoration of wetland ecosystems requires knowledge of wetland hydrologic patterns and an understanding of how those patterns affect wetland plant and animal populations.Within the Everglades, Florida, USA restoration, an applied science strategy including conceptual ecological models linking drivers to indicators is being used to organize current scientific understanding to support restoration efforts. A key driver of the ecosystem affecting the distribution and abundance of organisms is the timing, distribution, and volume of water flows that result in water depth patterns across the landscape. American alligators (Alligator mississippiensis) are one of the ecological indicators being used to assess Everglades restoration because they are a keystone species and integrate biological impacts of hydrological operations through all life stages. Alligator body condition (the relative fatness of an animal) is one of the metrics being used and targets have been set to allow us to track progress. We examined trends in alligator body condition using Fulton’s K over a 15 year period (2000–2014) at seven different wetland areas within the Everglades ecosystem, assessed patterns and trends relative to restoration targets, and related those trends to hydrologic variables. We developed a series of 17 a priori hypotheses that we tested with an information theoretic approach to identify which hydrologic factors affect alligator body condition. Alligator body condition was highest throughout the Everglades during the early 2000s and is approximately 5–10% lower now (2014). Values have varied by year, area, and hydrology. Body condition was positively correlated with range in water depth and fall water depth. Our top model was the “Current” model and included variables that describe current year hydrology (spring depth, fall depth, hydroperiod, range, interaction of range and fall depth, interaction of range and hydroperiod). Across all models, interaction

  14. Rapid suppression of testosterone secretion after capture in male American alligators (Alligator mississippiensis).

    PubMed

    Lance, Valentine A; Elsey, Ruth M; Butterstein, George; Trosclair, Phillip L

    2004-01-15

    All reptiles studied to date show an increase in circulating corticosterone following capture. This rise in corticosterone has also been shown in a number of instances to result in a decline in reproductive steroids within hours after capture. As a result of these observations it has been considered imperative to collect blood samples as soon as possible after capture to get reliable measures of reproductive hormones. It has been claimed, however, that there is no effect of capture stress on reproductive steroids in juvenile alligators held for 2 h following capture. As we generally reject blood samples that are not collected within 15 min of capture we decided to reinvestigate the effect of short-term capture (2 h) on corticosterone and testosterone in male alligators. Four groups of alligators, ranging in size from 74 to 212 cm total length were captured in a 2-week period in May, the time of year when testosterone levels are highest. Two groups were captured during the day (eight bled at capture and again at 2 h, eight bled at 2 h only) and two at night (10 bled at capture and again at 2 h, 10 bled at 2 h only). Testosterone and corticosterone in alligators bled immediately on capture and at 2 h were not significantly different in the AM and PM samples so the results were combined (Initial bleed: corticosterone, 0.95 +/- 0.09 ng/ml, n=18; testosterone, 6.06 +/- 2.09 ng/ml, n=18. Two-hour bleed: corticosterone 15.68 +/- 1.91, n=18; testosterone, 2.75 +/- 0.79, n=18). Both the increase in corticosterone and the decline in testosterone at 2 h were significant (p<0.05). Corticosterone and testosterone in the alligators sampled only once at 2 h were not significantly different from the 2-h values in alligators sampled twice (corticosterone 15.04 +/- 1.29, n=18; testosterone, 1.85 +/- 0.62, n=18). These results clearly demonstrate that short-term capture stress results in a significant decline in testosterone in male alligators.

  15. Hypoxic alligator embryos: chronic hypoxia, catecholamine levels and autonomic responses of in ovo alligators.

    PubMed

    Eme, John; Altimiras, Jordi; Hicks, James W; Crossley, Dane A

    2011-11-01

    Hypoxia is a naturally occurring environmental challenge for embryonic reptiles, and this is the first study to investigate the impact of chronic hypoxia on the in ovo development of autonomic cardiovascular regulation and circulating catecholamine levels in a reptile. We measured heart rate (f(H)) and chorioallantoic arterial blood pressure (MAP) in normoxic ('N21') and hypoxic-incubated ('H10'; 10% O(2)) American alligator embryos (Alligator mississippiensis) at 70, 80 and 90% of development. Embryonic alligator responses to adrenergic blockade with propranolol and phentolamine were very similar to previously reported responses of embryonic chicken, and demonstrated that embryonic alligator has α and β-adrenergic tone over the final third of development. However, adrenergic tone originates entirely from circulating catecholamines and is not altered by chronic hypoxic incubation, as neither cholinergic blockade with atropine nor ganglionic blockade with hexamethonium altered baseline cardiovascular variables in N21 or H10 embryos. In addition, both atropine and hexamethonium injection did not alter the generally depressive effects of acute hypoxia - bradycardia and hypotension. However, H10 embryos showed significantly higher levels of noradrenaline and adrenaline at 70% of development, as well as higher noradrenaline at 80% of development, suggesting that circulating catecholamines reach maximal levels earlier in incubation for H10 embryos, compared to N21 embryos. Chronically elevated levels of catecholamines may alter the normal balance between α and β-adrenoreceptors in H10 alligator embryos, causing chronic bradycardia and hypotension of H10 embryos measured in normoxia. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Variations in hepatic biomarkers in American alligators (Alligator mississippiensis) from three sites in Florida, USA.

    PubMed

    Gunderson, Mark P; Pickett, Melissa A; Martin, Justin T; Hulse, Elizabeth J; Smith, Spenser S; Smith, Levi A; Campbell, Rachel M; Lowers, Russell H; Boggs, Ashley S P; Guillette, Louis J

    2016-07-01

    Sub-individual biomarkers are sub-lethal biological responses commonly used in the assessment of wildlife exposure to environmental contaminants. In this study, we examined the activity of glutathione-s-transferase (GST) and lactate dehydrogenase (LDH), and metallothionein (MT) concentrations among captive-raised alligator hatchlings, wild-caught juveniles, and wild-caught adults. Juveniles and adults were collected from three locations in Florida (USA) with varying degrees of contamination (i.e. Lake Apopka (organochlorine polluted site), Merritt Island National Wildlife Refuge (NWR) (metal polluted site), and Lake Woodruff NWR (reference site)). We examined whether changes in the response of these three biomarkers were age and sex dependent or reflected site-specific variations of environmental contaminants. Juvenile alligators from Merritt Island NWR had higher MT concentrations and lower GST activity compared to those from the other two sites. This outcome was consistent with higher metal pollution at this location. Sexually dimorphic patterns of MT and GST (F > M) were observed in juvenile alligators from all sites, although this pattern was not observed in adults. GST activity was lower in captive-raised alligators from Lake Apopka and Merritt Island NWR as compared to animals from Lake Woodruff NWR, suggesting a possible developmental modulator at these sites. No clear patterns were observed in LDH activity. We concluded that GST and MT demonstrate age and sex specific patterns in the alligators inhabiting these study sites and that the observed variation among sites could be due to differences in contaminant exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Altered gonadal expression of TGF-β superfamily signaling factors in environmental contaminant-exposed juvenile alligators.

    PubMed

    Moore, Brandon C; Milnes, Matthew R; Kohno, Satomi; Katsu, Yoshinao; Iguchi, Taisen; Woodruff, Teresa K; Guillette, Louis J

    2011-10-01

    Environmental contaminant exposure can influence gonadal steroid signaling milieus; however, little research has investigated the vulnerability of non-steroidal signaling pathways in the gonads. Here we use American alligators (Alligator mississippiensis) hatched from field-collected eggs to analyze gonadal mRNA transcript levels of the activin-inhibin-follistatin gene expression network and growth differentiation factor 9. The eggs were collected from Lake Woodruff National Wildlife Refuge, a site with minimal anthropogenic influence, and Lake Apopka, a highly contaminated lake adjacent to a former EPA Superfund site. The hatchling alligators were raised for 13 months under controlled conditions, thus limiting differences to embryonic origins. Our data reveal sexually dimorphic mRNA expression in 13-month-old alligator gonads similar to patterns established in vertebrates with genetic sex determination. In addition, we observed a relationship between lake of origin and mRNA expression of activin/inhibin subunits α and βB, follistatin, and growth differentiation factor 9. Our study suggests that embryonic exposure to environmental contaminants can affect future non-steroidal signaling patterns in the gonads of a long-lived species. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Umbilical scarring in hatchling American alligators

    USGS Publications Warehouse

    Wiebe, J.J.; Sepulveda, M.S.; Buckland, J.E.; Anderson, S.R.; Gross, T.S.

    2004-01-01

    Umbilical scarring is the presence of excess scar tissue deposited between abdominal dermal layers at the site of yolk sac absorption in hatchling American alligators (Alligator mississippiensis). The presence of this dermal condition plays a key evaluatory role in the overall quality and subsequent value for various commercial leather products. Despite the prevalent nature of this condition, currently the industry has no standardized protocols for its quantification. The objectives of this study were to examine the relationship between hatchling weight and age and incidence of umbilical scarring and to develop a quantifiable and reproducible technique to measure this dermal condition in hatchling American alligators. Thirty eggs from each of nine clutches were incubated in two separate incubators at different facilities and hatchling umbilical scarring was measured at 2 and 10 days of age using digital calipers. Umbilical area was calculated by multiplying umbilical length times umbilical width. There was a significant effect of both age and clutch on umbilical area (overall decline of 64%) by 10 days post-hatch. However, only five of the nine clutches utilized expressed a noticeable decline in the size of this dermal condition (range 67-74%). We had hypothesized that larger hatchlings would have larger umbilical areas and a slower rate of improvement in this condition during the first few days post-hatch. The differences in umbilical area and percent decline with age across clutches, however, were not associated with differences in initial hatchling weights. Within clutches and time periods, hatchling weight had no significant effect on the size and/or rate of decline of this condition. ?? 2004 Published by Elsevier B.V.

  19. WILDLIFE - ALLIGATOR BEGINS TO CROSS KENNEDY PARKWAY

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Harold O'Connor, manager of the Merritt Island Wildlife Refuge, watches a 10-foot-long alligator inch its way toward a busy highway at the Kennedy Space Center. O'Connor, aided by assistant Jerome Carroll, not shown, guided the large gator to safety in a nearby pond, several miles south of the Vehicle Assembly Building, in background. The Apollo 12 astronauts will be launched no earlier than November 14, 1969, from the Kennedy Space Center on the Nation's second manned lunar landing mission.

  20. Habitat Suitability Index Models: American alligator

    USGS Publications Warehouse

    Newsom, John D.; Joanen, Ted; Howard, Rebecca J.

    1987-01-01

    A review and synthesis of existing information were used to develop a model for evaluating American alligator habitat quality. The model is applicable in marshes along the northern Gulf of Mexico. It is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are described.

  1. WILDLIFE - ALLIGATOR BEGINS TO CROSS KENNEDY PARKWAY

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Harold O'Connor, manager of the Merritt Island Wildlife Refuge, watches a 10-foot-long alligator inch its way toward a busy highway at the Kennedy Space Center. O'Connor, aided by assistant Jerome Carroll, not shown, guided the large gator to safety in a nearby pond, several miles south of the Vehicle Assembly Building, in background. The Apollo 12 astronauts will be launched no earlier than November 14, 1969, from the Kennedy Space Center on the Nation's second manned lunar landing mission.

  2. American Alligator Research on the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Lowers, Russell H.

    2010-01-01

    This slide presentation reviews the research conducted at the Kennedy Space Center on the American Alligator. The objectives of the research were to establish life history baseline at the Kennedy Space Center and at the Merit Island National Wildlife Reserve (MINWR). Some of the factors that were examined are: nesting success, movement patterns, and population structure. Another objective was to determine the overall health of the alligator population, by analyzing blood and tissue chemistry, and urine analysis. A third objective was to compare alligators at KSC/MINWR to the statewide population. Some of the results are shown in charts and graphs.

  3. American Alligator Research on the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Lowers, Russell H.

    2010-01-01

    This slide presentation reviews the research conducted at the Kennedy Space Center on the American Alligator. The objectives of the research were to establish life history baseline at the Kennedy Space Center and at the Merit Island National Wildlife Reserve (MINWR). Some of the factors that were examined are: nesting success, movement patterns, and population structure. Another objective was to determine the overall health of the alligator population, by analyzing blood and tissue chemistry, and urine analysis. A third objective was to compare alligators at KSC/MINWR to the statewide population. Some of the results are shown in charts and graphs.

  4. ENDOCRINE DISRUPTING CONTAMINANTS AND ALLIGATOR EMBRYOS: A LESSON FROM WILDLIFE?

    EPA Science Inventory

    Many xenobiotic compounds introduced into the environment by human activity adversely affect wildlife. A number of these contaminants have been hypothesized to induce non lethal, multigenerational effects by acting as endocrine disrupting agents. One case is that of the alligator...

  5. An alligator basks in the sun at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On the bank of a levee near Schwartz Rd. at Kennedy Space Center, an alligator suns itself with a wary eye out for trespassers. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  6. An alligator basks in the sun at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On the bank of a levee near Schwartz Rd. at Kennedy Space Center, an alligator suns itself with a wary eye out for trespassers. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  7. ENDOCRINE DISRUPTING CONTAMINANTS AND ALLIGATOR EMBRYOS: A LESSON FROM WILDLIFE?

    EPA Science Inventory

    Many xenobiotic compounds introduced into the environment by human activity adversely affect wildlife. A number of these contaminants have been hypothesized to induce non lethal, multigenerational effects by acting as endocrine disrupting agents. One case is that of the alligator...

  8. 109. Doughton Park Recreation Area. View of alligator back and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    109. Doughton Park Recreation Area. View of alligator back and the parkway seen from bluff mountain. Looking west. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  9. Influence of collection time on hematologic and immune markers in the American alligator (Alligator mississippiensis).

    PubMed

    Finger, John W; Williams, Robert J; Hamilton, Matthew T; Elsey, Ruth M; Oppenheimer, Victor A; Holladay, Steven D; Gogal, Robert M

    2015-01-01

    Crocodilians are important keystone species and indicators of environmental health. Much remains unknown, however regarding utility of field-collected crocodilian blood samples for ecologic assessments. Field sampling sites are also often distant to analysis centers, necessitating development of new techniques and panels of assays that will yield environmentally relevant data. Stability and viability of hematological and immunological indices have been of particular interest for linking ecosystem health to biomarkers in resident species. In this study, we investigated the effect of time at analysis post-blood sampling at 4 and 24 hr on a panel of potential biomarkers in alligator blood. Our results suggest alligator blood samples can be reliably evaluated for both hematologic and immunologic profile 24 hr after sampling.

  10. Morphology and histochemistry of juvenile male American alligator (Alligator mississippiensis) phallus.

    PubMed

    Moore, Brandon C; Mathavan, Ketan; Guillette, Louis J

    2012-02-01

    Phalli of male crocodilians transfer sperm to female cloaca during sexual intercourse, resulting in internal fertilization. For over a century there have been scientific descriptions of crocodilian phallus morphologies; however, little work has presented detailed cellular-level analyses of these structures. Here we present a histological investigation of the complex functional anatomy of the juvenile male American alligator phallus, including fibrous and vascular erectile structures, a variety of secretory epithelium morphologies, and observed immune cells. Using 3D reconstruction software, we show the shape and location of vascular erectile tissues within the phallus. Histochemical staining detected mucin-rich secretory cells in glandular epithelial cells of the phallic shaft and also of the semen-conducting ventral sulcus. Lymphoid aggregates, lymphocytes, and epithelial mucin coats suggest an active immune system in the phallus defending from both the external and intracloacal environments. These results better characterize the complexity of the alligator phallus and predict later reproductive functions during adulthood.

  11. Development of sympathetic cardiovascular control in embryonic, hatchling, and yearling female American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Elsey, Ruth M; Crossley, Dane A

    2013-06-01

    We used arterial tyramine injections to study development of sympathetic actions on in vivo heart rate and blood pressure in embryonic, hatching and yearling female American alligators. Tyramine is a pharmacological tool for understanding comparative and developmental sympathetic regulation of cardiovascular function, and this indirect sympathomimetic agent causes endogenous neuronal catecholamine release, increasing blood pressure and heart rate. Arterial tyramine injection in hatchling and yearling alligators caused the typical vertebrate response - rise in heart rate and blood pressure. However, in embryonic alligators, tyramine caused a substantial and immediate bradycardia at both 70% and 90% of embryonic development. This embryonic bradycardia was accompanied by hypotension, followed by a sustained hypertension similar to the hatchling and juvenile responses. Pretreatment with atropine injection (cholinergic receptor blocker) eliminated the embryonic hypotensive bradycardia, and phentolamine pretreatment (α-adrenergic receptor blocker) eliminated the embryonic hypotensive and hypertensive responses but not the bradycardia. In addition, hexamethonium pretreatment (nicotinic receptor blocker) significantly blunted embryos' bradycardic tyramine response. However, pretreatment with 6-hydroxydopamine, a neurotoxin that destroys catecholaminergic terminals, did not eliminate the embryonic bradycardia. Tyramine likely stimulated a unique embryonic response - neurotransmitter release from preganglionic nerve terminals (blocked with hexamethonium) and an acetylcholine mediated bradycardia with a secondary norepinephrine-dependent sustained hypertension. In addition, tyramine appears to stimulate sympathetic nerve terminals directly, which contributed to the overall hypertension in the embryonic, hatchling and yearling animals. Data demonstrated that humoral catecholamine control of cardiovascular function was dominant over the immature parasympathetic nervous system

  12. Chronic hypoxic incubation blunts a cardiovascular reflex loop in embryonic American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Hicks, James W; Crossley, Dane A

    2011-10-01

    Hypoxia is a naturally occurring environmental challenge for embryonic non-avian reptiles, and this study is the first to investigate the impact of chronic hypoxia on a possible chemoreflex loop in a developing non-avian reptile. We measured heart rate and blood pressure in normoxic and hypoxic-incubated (10% O(2)) American alligator embryos (Alligator mississippiensis) at 70 and 90/95% of development. We hypothesized that hypoxic incubation would blunt embryonic alligators' response to a reflex loop stimulated by phenylbiguanide (PBG), a 5-HT(3) receptor agonist that stimulates vagal pulmonary C-fiber afferents. PBG injection caused a hypotensive bradycardia in 70 and 95% of development embryos (paired t tests, P < 0.05), a response similar to mammals breathing inspired air (all injections made through occlusive catheter in tertiary chorioallantoic membrane artery). Hypoxic incubation blunted the bradycardic response to PBG in embryos at 95% of development (two-way ANOVA, P < 0.01). We also demonstrated that the vagally mediated afferent limb of this reflex can be partially or completely blocked in ovo with a 5-HT(3) receptor blockade using ondansetron hydrochloride dihydrate (OHD), with a ganglionic blockade using hexamethonium, or with a cholinergic blockade using atropine. Atropine eliminated the hypotensive and bradycardic responses to PBG, and OHD and hexamethonium significantly blunted these responses. This cardiovascular reflex mediated by the vagus was affected by hypoxic incubation, suggesting that reptilian sympathetic and parasympathetic reflex loops have the potential for developmental plasticity in response to hypoxia. We suggest that the American alligator, with an extended length of time between each developmental stage relative to avian species, may provide an excellent model to test the cardiorespiratory effects of prolonged exposure to changes in atmospheric gases. This extended period allows for lengthy studies at each stage without the

  13. Effects of dehydration on cardiovascular development in the embryonic American alligator (Alligator mississipiensis).

    PubMed

    Tate, Kevin B; Eme, John; Swart, Justin; Conlon, J Michael; Crossley, Dane A

    2012-07-01

    Effects of dehydration on reptilian embryonic cardiovascular function are unknown. Here, we present the first morphological and physiological data quantifying the cumulative effects of four acute dehydration events on the embryonic American alligator, Alligator mississipiensis. We hypothesized that dehydration would alter embryonic morphology, reduce blood volume and augment the response to angiotensin II (Ang II), a key osmotic and blood volume regulatory response element in adult vertebrates. Drying events at 30%, 40%, 50%, and 60% of embryonic incubation reduced total egg water content by 14.43 ± 0.37 g, a 3.4 fold increase relative to controls. However, embyronic blood volume was greater in the dehydration group at 70% of embryonic incubation compared to controls (0.39 ± 0.044 mLg(-1) and 0.22 ± 0.03 mLg(-1), respectively), however, both groups were similar at 90% of incubation (0.18 ± 0.02 mLg(-1) in the controls and 0.23 ± 0.03 mLg(-1) in the dehydrated group). Dehydration altered the morphological phenotype and resulted in an overall reduction in embryonic mass at both incubation time points measured. Dehydration also altered the physiological phenotype, resulting in embryonic alligators that were relatively bradycardic at 90% of incubation. Arterial Ang II injections resulted in a dose dependent hypertension, which increased in intensity over the span of incubation studied. While progressive incubation altered the Ang II response, dehydration had no impact on the cardiovascular responses to the peptide. Quantification of Ang II type-1 receptor protein using western blot analysis illustrated that dehydration condition and incubation time point did not alter protein quantity. Collectively, our results show that dehydration during embryonic development of the American alligator alters embryonic morphology and baseline heart rate without altering arterial pressure and response to Ang II.

  14. Perfluorinated alkyl acids in plasma of American alligators (Alligator mississippiensis) from Florida and South Carolina.

    PubMed

    Bangma, Jacqueline T; Bowden, John A; Brunell, Arnold M; Christie, Ian; Finnell, Brendan; Guillette, Matthew P; Jones, Martin; Lowers, Russell H; Rainwater, Thomas R; Reiner, Jessica L; Wilkinson, Philip M; Guillette, Louis J

    2017-04-01

    The present study aimed to quantitate 15 perfluoroalkyl acids (PFAAs) in 125 adult American alligators at 12 sites across the southeastern United States. Of those 15 PFAAs, 9 were detected in 65% to 100% of samples: perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid, perfluorotridecanoic acid (PFTriA), perfluorotetradecanoic acid, perfluorohexanesulfonic acid (PFHxS), and perfluorooctane sulfonate (PFOS). Males (across all sites) showed significantly higher concentrations of 4 PFAAs: PFOS (p = 0.01), PFDA (p = 0.0003), PFUnA (p = 0.021), and PFTriA (p = 0.021). Concentrations of PFOS, PFHxS, and PFDA in plasma were significantly different among the sites in each sex. Alligators at both Merritt Island National Wildlife Refuge (FL, USA) and Kiawah Nature Conservancy (SC, USA) exhibited some of the highest PFOS concentrations (medians of 99.5 ng/g and 55.8 ng/g, respectively) in plasma measured to date in a crocodilian species. A number of positive correlations between PFAAs and snout-vent length were observed in both sexes, suggesting that PFAA body burdens increase with increasing size. In addition, several significant correlations among PFAAs in alligator plasma may suggest conserved sources of PFAAs at each site throughout the greater study area. The present study is the first to report PFAAs in American alligators, to reveal potential PFAA hot spots in Florida and South Carolina, and to provide a contaminant of concern when assessing anthropogenic impacts on ecosystem health. Environ Toxicol Chem 2017;36:917-925. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  15. [Heavy metals content and pH value in water environment of wild Chinese alligator (Alligator sinensis) habitat: a preliminary study].

    PubMed

    Jiang, Hongxing; Wu, Xiaobing; Wu, Lusheng

    2005-11-01

    In order to reveal the reasons of the dramatic decline of wild Chinese alligator population, an investigation on its habitat status was made across the National Natural Conservation Regions of Chinese alligator in south Anhui Province from 2002 to 2003. Water samples from 21 sites were collected, and their heavy metals (Cu, Zn, Cd and Pb) content and pH value were measured. The results showed that the pH value was 7.84 +/- 0.62, with no significant difference between the waters with and without Chinese alligator, but with significant difference (P< 0.01) among 3 Chinese alligator habitats. In the waters with and without Chinese alligator, no significant difference was observed in the contents of test metals except Pb. The possible pollution source of Pb in wild Chinese alligator habitat was analyzed, which could provide reference for Chinese alligator conservation.

  16. Proteome analysis of the leukocytes from the American alligator (Alligator mississippiensis) using mass spectrometry.

    PubMed

    Darville, Lancia N F; Merchant, Mark E; Hasan, Azeem; Murray, Kermit K

    2010-12-01

    Mass spectrometry was used in conjunction with gel electrophoresis and liquid chromatography, to determine peptide sequences from American alligator (Alligator mississippiensis) leukocytes and to identify similar proteins based on homology. The goal of the study was to generate an initial database of proteins related to the alligator immune system. We have adopted a typical proteomics approach for this study. Proteins from leukocyte extracts were separated using two-dimensional gel electrophoresis and the major bands were excised, digested and analyzed by on-line nano-LC MS/MS to generate peptide sequences. The sequences generated were used to identify proteins and characterize their functions. The protein identity and characterization of the protein function were based on matching two or more peptides to the same protein by searching against the NCBI database using MASCOT and Basic Local Alignment Search Tool (BLAST). For those proteins with only one peptide matching, the phylum of the matched protein was considered. Forty-three proteins were identified that exhibit sequence similarities to proteins from other vertebrates. Proteins related to the cytoskeletal system were the most abundant proteins identified. These proteins are known to regulate cell mobility and phagocytosis. Several other peptides were matched to proteins that potentially have immune-related function.

  17. Variation in perfluoroalkyl acids in the American alligator (Alligator mississippiensis) at Merritt Island National Wildlife Refuge.

    PubMed

    Bangma, Jacqueline T; Reiner, Jessica L; Jones, Martin; Lowers, Russell H; Nilsen, Frances; Rainwater, Thomas R; Somerville, Stephen; Guillette, Louis J; Bowden, John A

    2017-01-01

    This study aimed to quantify concentrations of fifteen perfluoroalkyl acids (PFAAs) in the plasma of American alligators (Alligator mississippiensis) inhabiting wetlands surrounding the Kennedy Space Center (KSC) in Florida, USA located at Merritt Island National Wildlife Refuge (MINWR). Approximately 10 male and 10 female alligators (ntotal = 229) were sampled each month during 2008 and 2009 to determine if seasonal or spatial trends existed with PFAA burden. PFOS represented the highest plasma burden (median 185 ng/g) and PFHxS the second highest (median 7.96 ng/g). While no significant seasonal trends were observed, unique spatial trends emerged. Many of the measured PFAAs co-varied strongly together and similar trends were observed for PFOS, PFDA, PFUnA, and PFDoA, as well as for PFOA, PFHxS, PFNA, PFTriA, and PFTA, suggesting more than one source of PFAAs at MINWR. Higher concentrations of PFOS and the PFAAs that co-varied with PFOS were collected from animals around sites that included the Shuttle Landing Facility (SLF) fire house and the Neil Armstrong Operations and Checkout (O&C) retention pond, while higher concentrations of PFOA and the PFAA that co-varied with PFOA were sampled from animals near the gun range and the old fire training facility. Sex-based differences and snout-vent length (SVL) correlations with PFAA burden were also investigated. Published by Elsevier Ltd.

  18. Ultrastructure of the spermatozoon of the American Alligator, Alligator mississippiensis (Reptilia: Alligatoridae).

    PubMed

    Gribbins, Kevin M; Touzinsky, Katherine F; Siegel, Dustin S; Venable, Katherine J; Hester, Georgia L; Elsey, Ruth M

    2011-11-01

    This study details the ultrastructure of the spermatozoa of the American Alligator, Alligator mississippiensis. American Alligator spermatozoa are filiform and slightly curved. The acrosome is tapered at its anterior end and surrounded by the acrosome vesicle and an underlying subacrosomal cone, which rests just cephalic to the nuclear rostrum. One endonuclear canal extends from the subacrosomal cone through the rostral nucleus and deep into the nuclear body. The neck region separates the nucleus and midpiece and houses the proximal centriole and pericentriolar material. The distal centriole extends through the midpiece and has 9 × 3 sets of peripheral microtubules with a central doublet pair within the axoneme that is surrounded by a dense sheath. The midpiece is composed of seven to nine rings of mitochondria, which have combinations of concentrically and septate cristae. The principal piece has a dense fibrous sheath that surrounds an axoneme with a 9 + 2 microtubule arrangement. The sheath becomes significantly reduced in size caudally within the principal piece and is completely missing from the endpiece. Dense peripheral fibers, especially those associated with microtubule doublets 3 and 8, penetrate into the anterior portion of the principal piece axoneme. The data reported here hypothesize that sperm morphology is highly conserved in Crocodylia; however, specific morphological differences can exist between species.

  19. Estimated source intensity and active space of the American alligator (Alligator Mississippiensis) vocal display.

    PubMed

    Todd, Neil P McAngus

    2007-11-01

    In this article the results are reported of a study to measure the intensity of the vocal displays of a population of American alligators (Alligator mississippiensis). It was found that the dominant frequencies in air range between 20 and 250 Hz with a source sound pressure level (SPL) of 91-94 dB at 1 m. The active space for the air-borne component is defined by the background and was estimated to be in a range up to 159 m in the 125-200 Hz band. For the water-borne component the dominant frequency range was 20-100 Hz with a source SPL of 121-125 dB at 1 m. The active space in water is defined by hearing thresholds and was estimated to range up to 1.5 km in the 63-100 Hz band. In the lowest frequency bands, i.e., 16-50 Hz, the estimated active space for otolith detection of near-field particle motion in water ranged to 80 m, which compared significantly with far-field detection for these frequencies. It is suggested that alligator vocal communication may involve two distinct sensory mechanisms which may subserve the functions of scene analysis and reproduction, respectively.

  20. Seasonal androgen cycles in adult male American alligators (Alligator mississippiensis) from a barrier island population.

    PubMed

    Hamlin, Heather J; Lowers, Russell H; Guillette, Louis J

    2011-12-01

    The seasonal patterns of two primary plasma androgens, testosterone (T) and dehydroepiandrosterone (DHEA), were assessed in adult male alligators from the Merritt Island National Wildlife Refuge, a unique barrier island environment and home to the Kennedy Space Center in Florida. Samples were collected monthly from 2008 to 2009, with additional samples collected at more random intervals in 2007 and 2010. Plasma T concentrations peaked in April, coincident with breeding and courtship, and declined rapidly throughout the summer. Seasonal plasma T patterns in smaller though reproductively active adult males differed from those in their larger counterparts during the breeding season. Both size classes showed significant increases in plasma T concentration from February to March, at the beginning of the breeding season. However, smaller adults did not experience the peak in plasma T concentrations in April that were observed in larger adults, and their concentrations were significantly lower than those of larger males for the remainder of the breeding season. Plasma DHEA concentrations peaked in May and were significantly reduced by June. This is the first study to demonstrate the presence of DHEA in a crocodilian, and the high plasma DHEA concentrations that paralleled the animals' reproductive activity suggest a reproductive and/or behavioral role in adult male alligators. Similar to androgen variations in some birds, plasma DHEA concentrations in the alligators were considerably higher than T concentrations during the nonbreeding season, suggesting a potential role in maintaining nonbreeding seasonal aggression.

  1. Low cost of pulmonary ventilation in American alligators (Alligator mississippiensis) stimulated with doxapram.

    PubMed

    Skovgaard, Nini; Crossley, Dane A; Wang, Tobias

    2016-04-01

    To determine the costs of pulmonary ventilation without imposing severe oxygen limitations or acidosis that normally accompany exposures to hypoxia or hypercapnia, we opted to pharmacologically stimulate ventilation with doxapram (5 and 10 mg kg(-1)) in alligators. Doxapram is used clinically to alleviate ventilatory depression in response to anaesthesia and acts primarily on the peripheral oxygen-sensitive chemoreceptors. Using this approach, we investigated the hypothesis that pulmonary ventilation is relatively modest in comparison to resting metabolic rate in crocodilians and equipped seven juvenile alligators with masks for concurrent determination of ventilation and oxygen uptake. Doxapram elicited a dose-dependent and up to fourfold rise in ventilation, primarily by increasing ventilatory frequency. The accompanying rise in oxygen uptake was very small; ventilation in resting animals constitutes no more than 5% of resting metabolic rate. The conclusion that pulmonary ventilation is energetically cheap is consistent with earlier studies on alligators where ventilation was stimulated by hypoxia or hypercapnia. © 2016. Published by The Company of Biologists Ltd.

  2. Persistent Organochlorine Pesticides and their Metabolites in Alligator Livers from Lakes Apopka and Woodruff, Florida, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  3. Population status of the American alligator on the Savannah River Plant, South Carolina

    SciTech Connect

    Murphy, T.M.

    1981-04-01

    Estimates are presented of alligator numbers, size distribution, sex ratios, reproductive effort, and population trends for all major components of the entire Savannah River Plant (SRP) alligator population. Savannah River Plant operations have impacted the alligator population in many different ways. The formation of man-made reservoirs has dramatically increased the amount of aquatic habitat available to alligators and has therefore increased the carrying capacity of the SRP site for this species. The thermal alteration of aquatic habitats on the SRP has also impacted the resident alligator population. Temperature elevations of aquatic habitat to greater than 38/sup 0/C result in the loss of this habitat to alligators. Moderate thermal increases on the other hand are responded to by alligator movement. The current information available on the alligators of the SRP suggests the following future trends: low density populations distant from thermally altered areas will continue at a low density with the exception of localized increases.

  4. Persistent Organochlorine Pesticides and their Metabolites in Alligator Livers from Lakes Apopka and Woodruff, Florida, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  5. Role of the left aortic arch and blood flows in embryonic American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Crossley, Dane A; Hicks, James W

    2011-04-01

    All embryonic and fetal amniotes possess a ductus(i) arteriosus(i) that allows blood to bypass the pulmonary circulation and the non-functional lungs. The central hemodynamic of embryonic reptiles are unique, given the additional systemic aorta that allows pulmonary circulatory bypass, the left aorta (LAo). The LAo exits in the right ventricle or 'pulmonary side' of reptilian hearts in both embryos and adults, but its functional significance in ovo is unknown. This study investigated the role of the LAo in embryonic American alligators by surgically occluding the LAo and measuring oxygen consumption and, in addition, measured hemodynamic responses to hypoxia in embryonic alligators. We measured systemic cardiac output and primary chorioallantoic membrane (CAM) artery blood flow for normoxic and hypoxic-incubated (10% O(2)) American alligator embryos (Alligator mississippiensis). Chronic blood flow (1-124 h) in the primary CAM artery for hypoxic-incubated embryos (92 ± 26 ml min(-1) kg(-1)) was elevated when compared with normoxic-incubated embryos (29 ± 14 ml min(-1) kg(-1), N = 6; P = 0.039). For hypoxic-incubated embryos, acute LAo blood flow (49.6 ± 24.4 ml min(-1) kg(-1)) was equivalent to the combined flow of the three systemic great vessels that arise from the left ventricle, the right aorta, common carotid and subclavian arteries (43.6 ± 21.5 ml min(-1) kg(-1), N = 5). Similarly, for normoxic-incubated embryos, LAo blood flow (27.3 ± 6.6 ml min(-1) kg(-1)) did not statistically differ from the other three vessels (18.4 ± 4.9 ml min(-1) kg(-1), N = 5). This study contains the first direct test of LAo function and the first measurements of blood flow in an embryonic reptile. These data support the hypotheses that embryonic alligators utilize the LAo to divert a significant amount of right ventricular blood into the systemic circulation, and that CAM blood flow increases following chronic hypoxic conditions. However, surgical occlusion of the LAo did not

  6. Ecological studies on the American alligator (Alligator mississippiensis) on the Savannah River Plant. Comprehensive Cooling Water Study: Final report

    SciTech Connect

    Seigel, R.A.; Brandt, L.A.; Knight, J.L.; Novak, S.S.

    1986-06-01

    The American alligator (Alligator mississippiensis) is the largest vertebrate of the Savannah River Plant (SRP), reaching a maximum length of 3.7 meters (12 feet) and weighing up to 175 kg (385 pounds). Currently, populations in coastal South Carolina are considered Threatened, whereas populations in inland areas (such as the SRP) are still Endangered. Because of their legal status and economic and ecological importance, it is important to determine the environmental impacts of SRP operations on the local alligator population. The major objectives under the Endangered Species Program of the Comprehensive Cooling Water Study (CCWS) were as follows: (1) document and compare the present status and distribution of alligators on the SRP to previous surveys, in order to determine long-term changes in population abundance; (2) establish baseline population and ecological parameters of the Steel Creek population so that the ecological effects of L-Reactor operations can be determined, and (3) conduct ecological research on the immediate impacts of thermal effluents on American alligators. Gladden et al., (1985) summarized data on previous population surveys, temporal changes in the Par Pond population, preliminary results of the Steel Creek surveys and Savannah River Ecology Laboratory (SREL) research on the effects of thermal effluents. This report summarizes the current status of the SRP population, presents data on the abundance, movement patterns and activity cycles of the Steel Creek population, and presents additional data on the effect of cooling water releases on alligator ecology and behavior.

  7. Episodic breathing in alligators: role of sensory feedback.

    PubMed

    Douse, M A; Mitchell, G S

    1992-01-01

    The episodic breathing pattern in many reptiles consists of two or more clustered breaths separated by variable non-ventilatory periods. This pattern is commonly postulated to result from oscillations in lung and/or blood PO2 or PCO2 via chemoreceptor feedback. We tested this hypothesis by monitoring breathing pattern in: (1) awake, undisturbed alligators and (2) sedated alligators (approx. 25 mg/kg pentobarbital, i.p.; 3 days prior to data collection). In sedated alligators, measurements were made: (1) before and after bilateral cervical vagotomy, a procedure that removes peripheral arterial chemoreceptors, CO2-sensitive intrapulmonary chemoreceptors and pulmonary stretch receptors (n = 6); and (2) during unidirectional ventilation (UDV) at high flow rates (greater than 2 L/min), thereby minimizing oscillations in lung and blood PO2 and PCO2 (n = 6). Measurements on sedated alligators were made at 30 and 20 degrees C in each of these conditions. In awake, undisturbed alligators, breathing was typically episodic with 2-7 breaths/cluster, although the pattern was easily altered (increased breaths/cluster) by even seemingly minor disturbances. In sedated alligators, episodic breathing was still evident after vagotomy, but only at increased inspired CO2; at 5% CO2 four of six alligators exhibited episodic breathing consisting of 2-3 breaths/cluster interspersed with occasional single breaths. An episodic breathing pattern was also evident during UDV; at low levels of CO2, 2-4 breaths/cluster interspersed with occasional single breaths were evident in four alligators, while two had 6-8 breaths/cluster. Increasing CO2 in the UDV gas stream generally increased the number of breaths/cluster. After vagotomy, all six alligators could manifest an episodic breathing pattern during UDV in at least one CO2 condition (greater than 2 breaths/cluster interspersed with occasional single breaths). The episodic breathing pattern was very labile, sometimes changing to single breaths

  8. 33 CFR 165.T05-0091 - Safety Zone; Alligator River, NC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; Alligator River, NC... Safety Zone; Alligator River, NC. (a) Definitions. For the purposes of this section, Captain of the Port... on the waters of the Alligator River centered at (35°54′3″ N/076°00′25″ W) a position directly under...

  9. 78 FR 57480 - Safety Zone; 2013 Annual Islamorada Swim for Alligator Lighthouse, Atlantic Ocean; Islamorada, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2013 Annual Islamorada Swim for Alligator... Islamorada, Florida, during the 2013 Annual Islamorada Swim for Alligator Lighthouse on September 21, 2013.... is hosting the 1st Annual Islamorada Swim for Alligator Lighthouse. The event will be held on the...

  10. Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida.

    PubMed

    Schoeb, Trenton R; Heaton-Jones, Terrell G; Clemmons, Roger M; Carbonneau, Dwayne A; Woodward, Allan R; Shelton, Diane; Poppenga, Robert H

    2002-04-01

    From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semicircularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.

  11. Unidirectional airflow in the lungs of alligators.

    PubMed

    Farmer, C G; Sanders, Kent

    2010-01-15

    The lungs of birds move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi), whereas in the lungs of mammals and presumably other vertebrates, air moves tidally into and out of terminal gas-exchange structures, which are cul-de-sacs. Unidirectional flow purportedly depends on bellowslike ventilation by air sacs and may have evolved to meet the high aerobic demands of sustained flight. Here, we show that air flows unidirectionally through parabronchi in the lungs of the American alligator, an amphibious ectotherm without air sacs, which suggests that this pattern dates back to the basal archosaurs of the Triassic and may have been present in their nondinosaur descendants (phytosaurs, aetosaurs, rauisuchians, crocodylomorphs, and pterosaurs) as well as in dinosaurs.

  12. Ontogenetic development of otoliths in Alligator Gar

    USGS Publications Warehouse

    Long, James M.; Snow, Richard A.

    2016-01-01

    The Alligator Gar Atractosteus spatula is a species of conservation concern throughout its range, and better definition of otoliths during early development would aid understanding its life history and ecology. We conducted X-ray computed tomography scans, scanning electron microscopy, and light microscopy to examine the three pairs of otoliths and how they developed over time in relation to fish size and age. The sagittae are the largest, possessing distinct dorsal and ventral lobes covered with small otoconia concentrated in the sulcul region. The sagittae exhibited allometric growth, increasing more rapidly in the ventral lobe than in the dorsal. The asterisci were smaller and also exhibited small otoconia on their surface, but much less than the sagittae. The lapilli were oriented laterally, in contrast to the sagittae and asterisci, which were oriented vertically, with a hump on the dorsum and very large otoconia on the lateral surface that appeared to fuse into the main otolith as the fish grew. Based on size measurements and ring counts in all three pairs of otoliths from 101 known-age Alligator Gar sampled weekly through 91 d after hatch, we developed regression models to examine otolith growth and predict age. All relationships were significant and highly explanatory, but the strongest relationships were between otolith and fish size (for measurements from sagittae) and for age predictions from the lapillus. Age prediction models all resulted in a slope near unity, indicating that ring deposition occurred approximately daily. The first ring in sagittae and lapilli corresponded to swim-up, whereas the first ring formed in asterisci approximately 8 d after swim-up. These results fill a gap in knowledge and can aid understanding of evolutionary processes as well as provide useful information for management and conservation.

  13. Differential incubation temperatures result in dimorphic DNA methylation patterning of the SOX9 and aromatase promoters in gonads of alligator (Alligator mississippiensis) embryos.

    PubMed

    Parrott, Benjamin B; Kohno, Satomi; Cloy-McCoy, Jessica A; Guillette, Louis J

    2014-01-01

    Environmental factors are known to influence sex determination in many nonmammalian vertebrates. In all crocodilians studied thus far, temperature is the only known determinant of sex. However, the molecular mechanisms mediating the effect of temperature on sex determination are not known. Aromatase (CYP19A1) and SOX9 play critical roles in vertebrate sex determination and gonadogenesis. Here, we used a variety of techniques to investigate the potential roles of DNA methylation patterning on CYP19A1 and SOX9 expression in the American alligator, an organism that relies on temperature-dependent sex determination. Our findings reveal that developing gonads derived from embryos incubated at a male-producing temperature (MPT) show elevated CYP19A1 promoter methylation and decreased levels of gene expression relative to incubation at a female-producing temperature (FPT). The converse was observed at the SOX9 locus, with increased promoter methylation and decreased expression occurring in embryonic gonads resulting from incubation at FPT relative to that of MPT. We also examined the gonadal expression of the three primary, catalytically active DNA methyltransferase enzymes and show that they are present during critical stages of gonadal development. Together, these data strongly suggest that DNA methylation patterning is a central component in coordinating the genetic cascade responsible for sexual differentiation. In addition, these data raise the possibility that DNA methylation could act as a key mediator integrating temperature into a molecular trigger that determines sex in the alligator.

  14. Alligator physiology and life history: the importance of temperature.

    PubMed

    Lance, Valentine A

    2003-07-01

    Alligators are the most northerly distributed of the extant Crocodilia. Reproducing populations are found as far north as 35 degrees latitude in the freshwater marshes and rivers of coastal North Carolina, and as far south as 25 degrees latitude in the Florida Keys. Thus different populations are exposed to very different annual thermal cycles. Alligators stop eating when ambient temperature drops below 16 degrees C. This anorexia lasts at least 6 months at 35 degrees latitude. In southwest Louisiana alligators stop feeding in October and do not resume feeding until late March or early April. It is only during the warmer months when actively feeding that growth occurs. Even with this restricted growing season Louisiana alligators grow about 30 cm a year for the first 6 years. When alligators reach sexual maturity at about 1.85 m total length growth slows in both sexes, but is significantly slower in females than males. As a result of differences in thermal regime sexual maturity is estimated at around 18 years in North Carolina and about 10 years in Louisiana. Females lay one clutch of around 40 eggs in June, but the time of nesting is also tightly linked to temperature. In a cool spring nesting can occur as late as July 5th, and in a warm spring as early as June 5th. Immature male alligators undergo a seasonal hormonal cycle similar to fully mature breeding males, but testosterone levels differ by an order of magnitude. The number of mature females reproducing each year is rarely greater than 50%, but data on internest interval is lacking. Immature female alligators show no seasonal hormonal cycle.

  15. RNA-seq analysis of the gonadal transcriptome during Alligator mississippiensis temperature-dependent sex determination and differentiation.

    PubMed

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Parrott, Benjamin B; Yamaguchi, Katsushi; Ogino, Yukiko; Miyakawa, Hitoshi; Lowers, Russell H; Shigenobu, Shuji; Guillette, Louis J; Iguchi, Taisen

    2016-01-25

    The American alligator (Alligator mississippiensis) displays temperature-dependent sex determination (TSD), in which incubation temperature during embryonic development determines the sexual fate of the individual. However, the molecular mechanisms governing this process remain a mystery, including the influence of initial environmental temperature on the comprehensive gonadal gene expression patterns occurring during TSD. Our characterization of transcriptomes during alligator TSD allowed us to identify novel candidate genes involved in TSD initiation. High-throughput RNA sequencing (RNA-seq) was performed on gonads collected from A. mississippiensis embryos incubated at both a male and a female producing temperature (33.5 °C and 30 °C, respectively) in a time series during sexual development. RNA-seq yielded 375.2 million paired-end reads, which were mapped and assembled, and used to characterize differential gene expression. Changes in the transcriptome occurring as a function of both development and sexual differentiation were extensively profiled. Forty-one differentially expressed genes were detected in response to incubation at male producing temperature, and included genes such as Wnt signaling factor WNT11, histone demethylase KDM6B, and transcription factor C/EBPA. Furthermore, comparative analysis of development- and sex-dependent differential gene expression revealed 230 candidate genes involved in alligator sex determination and differentiation, and early details of the suspected male-fate commitment were profiled. We also discovered sexually dimorphic expression of uncharacterized ncRNAs and other novel elements, such as unique expression patterns of HEMGN and ARX. Twenty-five of the differentially expressed genes identified in our analysis were putative transcriptional regulators, among which were MYBL2, MYCL, and HOXC10, in addition to conventional sex differentiation genes such as SOX9, and FOXL2. Inferred gene regulatory network was constructed

  16. Body temperature null distributions in reptiles with nonzero heat capacity: seasonal thermoregulation in the American alligator (Alligator mississippiensis).

    PubMed

    Seebacher, Frank; Elsey, Ruth M; Trosclair, Phillip L

    2003-01-01

    Regulation of body temperature may increase fitness of animals by ensuring that biochemical and physiological processes proceed at an optimal rate. The validity of current methods of testing whether or not thermoregulation in reptiles occurs is often limited to very small species that have near zero heat capacity. The aim of this study was to develop a method that allows estimation of body temperature null distributions of large reptiles and to investigate seasonal thermoregulation in the American alligator (Alligator mississippiensis). Continuous body temperature records of wild alligators were obtained from implanted dataloggers in winter (n=7, mass range: 1.6-53.6 kg) and summer (n=7, mass range: 1.9-54.5 kg). Body temperature null distributions were calculated by randomising behavioural postures, thereby randomly altering relative animal surface areas exposed to different avenues of heat transfer. Core body temperatures were predicted by calculations of transient heat transfer by conduction and blood flow. Alligator body temperatures follow regular oscillations during the day. Occasionally, body temperature steadied during the day to fall within a relatively narrow range. Rather than indicating shuttling thermoregulation, however, this pattern could be predicted from random movements. Average daily body temperature increases with body mass in winter but not in summer. Daily amplitudes of body temperature decrease with increasing body mass in summer but not in winter. These patterns result from differential exposure to heat transfer mechanisms at different seasons. In summer, alligators are significantly cooler than predictions for a randomly moving animal, and the reverse is the case in winter. Theoretical predictions show, however, that alligators can be warmer in winter if they maximised their sun exposure. We concluded that alligators may not rely exclusively on regulation of body temperature but that they may also acclimatise biochemically to seasonally

  17. Effects of prolonged lung inflation or deflation on pulmonary stretch receptor discharge in the alligator (Alligator mississippiensis).

    PubMed

    Marschand, Rachel E; Wilson, Jenna L; Burleson, Mark L; Crossley, Dane A; Hedrick, Michael S

    2014-08-15

    The American alligator (Alligator mississippiensis) is a semi-aquatic diving reptile that has a periodic breathing pattern. Previous work identified pulmonary stretch receptors, that are rapidly and slowly adapting, as well as intrapulmonary chemoreceptors (IPC), sensitive to CO2, that modulate breathing patterns in alligators. The purpose of the present study was to quantify the effects of prolonged lung inflation and deflation (simulated dives) on pulmonary stretch receptors (PSR) and/or IPC discharge characteristics. The effects of airway pressure (0-20 cm H2O), hypercapnia (7% CO2), and hypoxia (5% O2) on dynamic and static responses of PSR were studied in juvenile alligators (mean mass=246 g) at 24°C. Alligators were initially anesthetized with isoflurane, cranially pithed, tracheotomized and artificially ventilated. Vagal afferent tonic and phasic activity was recorded with platinum hook electrodes. Receptor activity was a mixture of slowly adapting PSR (SAR) and rapidly adapting PSR (RAR) with varying thresholds and degrees of adaptation, without CO2 sensitivity. Receptor activity before, during and after 1 min periods of lung inflation and deflation was quantified to examine the effect of simulated breath-hold dives. Some PSR showed a change in dynamic response, exhibiting inhibition for several breaths after prolonged lung inflation. Following 1 min deflation, RAR, but not SAR, exhibited a significant potentiation of burst frequency relative to control. For SAR, the post-inflation receptor inhibition was blocked by CO2 and hypoxia; for RAR, the post-inflation inhibition was potentiated by CO2 and blocked by hypoxia. These results suggest that changes in PSR firing following prolonged inflation and deflation may promote post-dive ventilation in alligators. We hypothesize that PSR in alligators may be involved in recovery of breathing patterns and lung volume during pre- and post-diving behavior and apneic periods in diving reptiles.

  18. Association of West Nile virus with lymphohistiocytic proliferative cutaneous lesions in American alligators (Alligator mississippiensis) detected by RT-PCR.

    PubMed

    Nevarez, Javier G; Mitchell, Mark A; Morgan, Timothy; Roy, Alma; Johnson, April

    2008-12-01

    West Nile virus (WNV) is known to affect captive populations of alligators and, in some instances, cause significant mortalities. Alligators have been shown to amplify the virus, serve as a reservoir host, and even represent a source of infection for humans. This study describes a cutaneous manifestation of WNV in captive-reared American alligators (Alligator mississippiensis), previously described as lymphohistiocytic proliferative syndrome of alligators (LPSA), based on the findings of gross examination, histopathologic evaluation, WNV antibody testing, and WNV reverse transcriptase polymerase chain reaction (RT-PCR). Forty alligators with LPSA and 41 controls were examined. There was a significant difference (P = 0.01(-21)) in the WNV serostatus between the treatment group (100%) and the control group (0%, 95% CI: 0-7.3%). In the treatment group, 97.5% (39/40) (95% CI: 92.7-102.3%) of the LPSA skin lesions were positive for WNV via RT-PCR. Of the skin sections within the treatment group that had no LPSA lesions, 7.5% (3/40) (95% CI: 0-15.7%) were positive for WNV. In the control group, all of the skin samples were negative for WNV (41/41) (0%; 95% CI: 0-7.3%). The LPSA skin lesions were significantly more likely to be WNV positive by RT-PCR when compared to control animals (P = 0.07(-20)) and normal skin sections from affected animals (P = 0.08(-16)). There was no significant difference in the WNV RT-PCR results between control animals and normal skin sections from affected animals (P = 0.24). These findings suggest that LPSA is a cutaneous manifestation of WNV in alligators.

  19. Hexavalent chromium is cytotoxic and genotoxic to American alligator cells.

    PubMed

    Wise, Sandra S; Wise, Catherine; Xie, Hong; Guillette, Louis J; Zhu, Cairong; Wise, John Pierce; Wise, John Pierce

    2016-02-01

    Metals are a common pollutant in the aquatic ecosystem. With global climate change, these levels are anticipated to rise as lower pH levels allow sediment bound metals to be released. The American alligator (Alligator mississippiensis) is an apex predator in the aquatic ecosystem and is considered a keystone species; as such it serves as a suitable monitor for localized pollution. One metal of increasing concern is hexavalent chromium (Cr(VI)). It is present in the aquatic environment and is a known human carcinogen and reproductive toxicant. We measured the cytotoxicity and genotoxicity of Cr(VI) in American alligator cells derived from scute tissue. We found that particulate and soluble Cr(VI) are both cytotoxic and genotoxic to alligator cells in a concentration-dependent manner. These data suggest that alligators may be used as a model for assessing the effects of environmental Cr(VI) contamination as well as for other metals of concern. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Evaluation of medetomidine-ketamine anesthesia with atipamezole reversal in American alligators (Alligator mississippiensis).

    PubMed

    Heaton-Jones, Terrell G; Ko, Jeff C H; Heaton-Jones, D L

    2002-03-01

    Sixteen captive and wild-caught American alligators (Alligator mississippiensis), seven juveniles (< or = 1 m total length [TL]; 6.75 +/- 1.02 kg), and nine adults (> or = 2 m TL; 36.65 +/- 38.85 kg), were successfully anesthetized multiple times (n = 33) with an intramuscular (i.m.) medetomidine-ketamine (MK) combination administered in either the triceps or masseter muscle. The juvenile animals required significantly larger doses of medetomidine (x = 220.1 +/- 76.9 microg/kg i.m.) and atipamezole (x = 1,188.5 -/+ 328.1 microg/kg i.m.) compared with the adults (medetomidine, x = 131.1 +/- 19.5 microg/kg i.m.; atipamezole, x = 694.0 +/- 101.0 microg/kg i.m.). Juvenile alligators also required higher (statistically insignificant) doses of ketamine (x = 10.0 +/- 4.9 mg/kg i.m.) compared with the adult animals (x = 7.5 +/- 4.2 mg/kg i.m.). The differences in anesthesia induction times (juveniles, x = 19.6 +/- 8.5 min; adults, x = 26.6 +/- 17.4 min) and recovery times (juveniles, x = 35.4 +/- 22.1 min; adults, x = 37.9 +/- 20.2 min) were also not statistically significant. Anesthesia depth was judged by the loss of the righting, biting, corneal and blink, and front or rear toe-pinch withdrawal reflexes. Recovery in the animals was measured by the return of reflexes, open-mouthed hissing, and attempts to high-walk to the opposite end of the pen. Baseline heart rates (HRs) were significantly higher in the juvenile animals (x = 37 +/- 4 beats/min) compared with the adults (x = 24 +/- 5 bpm). However, RRs (juveniles, x = 8 +/- 2 breaths/min; adults, x = 8 +/- 2 breaths/min) and body temperatures (juveniles, x = 24.1 +/- 1.1 degrees C; adults, x = 25.2 +/- 1.2 degrees C) did not differ between the age groups. In both groups, significant HR decreases were recorded within 30-60 min after MK administration. Cardiac arrhythmias (second degree atrio-ventricular block and premature ventricular contractions) were seen in two animals but were not considered life-threatening. Total

  1. Molecular and morphological characterization of a haemogregarine in the alligator snapping turtle, Macrochelys temminckii (Testudines: Chelydridae).

    PubMed

    Alhaboubi, Amer Rasool; Pollard, Dana A; Holman, Patricia J

    2017-01-01

    A severely underweight alligator snapping turtle Macrochelys temminckii Troost in Harlan, 1835, was found near Tyler, Texas, and taken to the Caldwell Zoo. Blood films were submitted to Texas A&M University, College Station, Texas, for morphological and molecular identification of haemogregarine-like inclusions in the red blood cells. Intraerythrocytic Haemogregarina sp. forms were found on microscopic examination at a parasitemia of <1 %. The morphology and morphometric data for the forms indicate similarity to Haemogregarina macrochelysi n. sp. Telford et al., 2009, previously reported in alligator snapping turtles in Florida and Georgia, but two characteristic stage forms were not shared between H. macrochelysi n. sp. and the parasite found in this report. The haemogregarine 18S ribosomal RNA gene (1555-bp fragment) was amplified and cloned, and five clones sequenced. The sequences were deposited in the NCBI GenBank database. All five showed ∼96 % identity to Haemogregarina balli Paterson and Desser, 1976, Hepatozoon sp., and Hemolivia stellata Petit et al., 1990. A 774-bp segment shared 98-99 % identity with the corresponding Haemogregarina sp. rDNA sequence (KR006985) from Caspian turtles (Mauremys caspica McDowell, 1964) in Iran. A neighbor-joining phylogenetic tree generated from aligned sequences from the clones, 26 hematozoa, Adelina dimidiata Schneider, 1875, and Cryptosporidium serpentis Levine, 1980, revealed the cloned sequences clustered on their own branch within the Haemogregarina spp. clade. No genetic data are available for H. macrochelysi n. sp. at this time, so it remains unclear if this parasite in a Texas alligator snapping turtle is conspecific with H. macrochelysi n. sp.

  2. The alligator gut microbiome and implications for archosaur symbioses

    PubMed Central

    Keenan, Sarah W.; Engel, Annette Summers; Elsey, Ruth M.

    2013-01-01

    Among vertebrate gastrointestinal microbiome studies, complete representation of taxa is limited, particularly among reptiles. Here, we provide evidence for previously unrecognized host-microbiome associations along the gastrointestinal tract from the American alligator, a crown archosaur with shared ancestry to extinct taxa, including dinosaurs. Microbiome compositional variations reveal that the digestive system consists of multiple, longitudinally heterogeneous microbiomes that strongly correlate to specific gastrointestinal tract organs, regardless of rearing histories or feeding status. A core alligator gut microbiome comprised of Fusobacteria, but depleted in Bacteroidetes and Proteobacteria common to mammalians, is compositionally unique from other vertebrate gut microbiomes, including other reptiles, fish, and herbivorous and carnivorous mammals. As such, modern alligator gut microbiomes advance our understanding of archosaur gut microbiome evolution, particularly if conserved host ecology has retained archosaur-specific symbioses over geologic time. PMID:24096888

  3. The alligator gut microbiome and implications for archosaur symbioses.

    PubMed

    Keenan, Sarah W; Engel, Annette Summers; Elsey, Ruth M

    2013-10-07

    Among vertebrate gastrointestinal microbiome studies, complete representation of taxa is limited, particularly among reptiles. Here, we provide evidence for previously unrecognized host-microbiome associations along the gastrointestinal tract from the American alligator, a crown archosaur with shared ancestry to extinct taxa, including dinosaurs. Microbiome compositional variations reveal that the digestive system consists of multiple, longitudinally heterogeneous microbiomes that strongly correlate to specific gastrointestinal tract organs, regardless of rearing histories or feeding status. A core alligator gut microbiome comprised of Fusobacteria, but depleted in Bacteroidetes and Proteobacteria common to mammalians, is compositionally unique from other vertebrate gut microbiomes, including other reptiles, fish, and herbivorous and carnivorous mammals. As such, modern alligator gut microbiomes advance our understanding of archosaur gut microbiome evolution, particularly if conserved host ecology has retained archosaur-specific symbioses over geologic time.

  4. Estimating sighting proportions of American alligator nests during helicopter survey

    USGS Publications Warehouse

    Rice, Kenneth G.; Percival, H. Franklin; Woodward, Allan R.

    2000-01-01

    Proportions of American alligator (Alligator mississippiensis) nests sighted during aerial survey in Florida were estimated based upon multiple surveys by different observers. We compared sighting proportions across habitats, nesting seasons, and observer experience levels. The mean sighting proportion across all habitats and years was 0.736 (SE=0.024). Survey counts corrected by the mean sighting proportion reliably predicted total nest counts (7?2=0.933). Sighting proportions did not differ by habitat type (P=0.668) or year P=0.328). Experienced observers detected a greater proportion of nests (P<0.0001) than did either less experienced or inexperienced observers. Reliable estimates of nest abundance can be derived from aerial counts of alligator nests when corrected by the appropriate sighting proportion.

  5. An examination of the sensory structures in the oral cavity of the American alligator (Alligator mississippiensis).

    PubMed

    Rehorek, Susan J; Duffy, Michael; Zacherl, Janelle R; Anand, Kusuma; Elsey, Ruth M; Smith, Timothy S

    2014-11-01

    The location and distribution of mucosal sensory structures of the crocodilian oral cavity are poorly understood. Although there are several descriptions of these structures in adults, nothing is known about their development. The purpose of this study was to document location, morphology, and relative abundance of these mucosal sensory structures in both hatchling and subadult alligators. Numerous mucosal sensory structures and pale staining dome-shaped papillae were observed only in the upper palate and tongue. In hatchlings, these papillae, which house either mechanoreceptive or chemosensory (taste buds) structures, were larger and more prevalent on the tongue than the upper palate. In the subadult, however, these papillae housed primarily mechanoreceptive structures and possibly degenerate taste buds. Although the presence of the mechanoreceptive structures in the palates of the suabadult alligator are to be expected, the loss of most taste buds is hitherto undocumented. Thus, there is morphological support for an ontogenetic shift in the role of the sensory palate, from a prey detection gustatory sensory system in hatchlings to a prey-manipulative mechanoreceptive system in subadults.

  6. Wave reflection effects in the central circulation of American alligators (Alligator mississippiensis): what the heart sees.

    PubMed

    Syme, Douglas A; Gamperl, A Kurt; Braun, Marvin H; Jones, David R

    2006-10-01

    A large central compliance is thought to dominate the hemodynamics of all vertebrates except birds and mammals. Yet large crocodilians may adumbrate the avian and mammalian condition and set the stage for significant wave transmission (reflection) effects, with potentially detrimental impacts on cardiac performance. To investigate whether crocodilians exhibit wave reflection effects, pressures and flows were recorded from the right aorta, carotid artery, and femoral artery of six adult, anesthetized American alligators (Alligator mississippiensis) during control conditions and after experimentally induced vasodilation and constriction. Hallmarks of wave reflection phenomena were observed, including marked differences between the measured profiles for flow and pressure, peaking of the femoral pressure pulse, and a diastolic wave in the right aortic pressure profile. Pulse wave velocity and peripheral input impedance increased with progressive constriction, and thus changes in both the timing and magnitude of reflections accounted for the altered reflection effects. Resolution of pressure and flow waves into incident and reflected components showed substantial reflection effects within the right aorta, with reflection coefficients at the first harmonic approaching 0.3 when constricted. Material properties measured from isolated segments of blood vessels revealed a major reflection site at the periphery and, surprisingly, at the junction of the truncus and right aorta. Thus, while our results clearly show that significant wave reflection phenomena are not restricted to birds and mammals, they also suggest that rather than cope with potential negative impacts of reflections, the crocodilian heart simply avoids them because of a large impedance mismatch at the truncus.

  7. Evaluation of an 18-micron filter for use in reptile blood transfusions using blood from American alligators (Alligator mississippiensis).

    PubMed

    Nevarez, Javier G; Cockburn, Jennifer; Kearney, Michael T; Mayer, Joerg

    2011-06-01

    Blood transfusions are a common therapeutic procedure in small animal medicine and have been investigated in some exotic species but little information is available about their safety and efficacy in reptiles. In human pediatrics and small animal practice, the Hemo-Nate18-micro filter is used to prevent embolic clots and particulate waste from entering the recipient during a transfusion. The goal of this study was to determine the hemolytic effect of an 18-micro Hemo-Nate filter for whole blood cell transfusions in reptiles using the American alligator (Alligator mississippiensis) as a reptilian model. Results revealed no significant difference in free plasma hemoglobin between the unfiltered and filtered samples (P = 0.21). There was no difference in the prefiltration and postfiltration packed cell volume (PCV) (P = 0.41). Results suggest that an 18-micro Hemo-Nate filter does not cause hemolysis or decrease the PCV of small quantities of alligator blood.

  8. An urban Northeastern United States alligator bite.

    PubMed

    Shepherd, Suzanne Moore; Shoff, William H

    2014-05-01

    Individuals who live and work in the Southeastern coastal range of the 3 US crocodilian carnivores, American alligators, American crocodiles, and caiman, understand the risks of reptile-human encounters. Individuals who live in other parts of the country maybe exposed through contact with exotic pets at private homes, small menageries, or petting zoos or from escaped or abandoned animals. During these encounters, individuals may be severely injured.Emergency medical services, law enforcement, and animal welfare workers in nonhabitat areas are usually not trained in the handling and safe removal of injured individuals from the scene when the reptile is present. The emergency management of large crocodilian injuries is similar to that of other major trauma; however, providers also must take into consideration the significant crush component potentially inflicted by the tremendous bite power and shaking inflicting during attacks by these large reptiles, appropriate antibiotic coverage for less common organisms that inhabit their mouths, and management of possible psychological distress, including posttraumatic stress disorder produced by such an unusual attack. Emergency physicians should support the development of a readily available national database of scientifically collect information on attacks to inform appropriate care and support efforts to explore responsible measures that the USDA Animal and Plant Health Inspection Service and other appropriate local, state, and federal agencies can take to ensure ethical and biologically sustainable management of our large reptiles, which also helps to ensure the safety of the public.

  9. Alligator osteoderms: mechanical behavior and hierarchical structure.

    PubMed

    Chen, Irene H; Yang, Wen; Meyers, Marc A

    2014-02-01

    Osteoderms are bony scutes embedded underneath the dermal layers of the skin acting as a protection of the alligator (Archosauria: Crocodylia) internal organs and tissues. Additionally, these scutes function as an aid in temperature regulation. The scutes are inter-linked by fibrous connective tissue. They have properties similar to bone and thus have the necessary toughness to provide protection against predators. The scutes consist of hydroxyapatite and have a porosity of approximately 12%. They have a disc-like morphology with a ridge along the middle of the plate, called the keel; the outer perimeter of the disc has depressions, grooves, and jagged edges which anchor the collagen and act as sutures. Computerized tomography reveals the pattern of elongated pores, which emanate from the keel in a radial pattern. Micro-indentation measurements along the cross-section show a zigzag behavior due to the porosity. Compression results indicate that the axial direction is the strongest (UTS ~67 MPa) and toughest (11 MJ/m(3)); this is the orientation in which they undergo the largest external compression forces from predator teeth. Toughening mechanisms are identified through observation of the damage progression and interpreted in mechanistic terms. They are: flattening of pores, microcrack opening, and microcrack growth and coalescence. Collagen plays an essential role in toughening and plasticity by providing bridges that impede the opening of the cracks and prevent their growth.

  10. Potential molecular wires and molecular alligator clips

    NASA Astrophysics Data System (ADS)

    Schumm, Jeffry S.; Pearson, Darren L.; Jones, LeRoy, II; Hara, Ryuichiro; Tour, James M.

    1996-12-01

    The synthesis of oligo(2-ethylphenylene-ethynylene)s, oligo(2-(0957-4484/7/4/023/img1-ethylheptyl)phenylene-ethynylene)s, and oligo(3-ethylthiophene-ethynylene)s is described via an iterative divergent convergent approach. Synthesized were the monomer, dimer, tetramer, octamer and 16-mer of the oligo(3-ethylthiophene-ethynylene)s and oligo(2-0957-4484/7/4/023/img1-ethylheptyl)phenylene-ethynylene)s. The 16-mers are 100 Å and 128 Å long, respectively. At each stage in the iteration, the length of the framework doubles. Only three sets of reaction conditions are needed for the entire iterative synthetic sequence; an iodination, a protodesilylation, and a Pd/Cu-catalyzed cross coupling. The oligomers were characterized spectroscopically and by mass spectrometry. The optical properties are presented which show the stage of optical absorbance saturation. The size exclusion chromatography values for the number average weights, relative to polystyrene, illustrate the tremendous differences in the hydrodynamic volume of these rigid rod oligomers versus the random coils of polystyrene. These differences become quite apparent at the octamer stage. The preparation of thiol-protected end groups is described. These may serve as molecular alligator clips for adhesion to gold surfaces. These oligomers may act as molecular wires in molecular electronic devices and they also serve as useful models for understanding related bulk polymers.

  11. Seasonal Variation of Total Mercury Burden in the American Alligator (Alligator Mississippiensis) at Merritt Island National Wildlife Refuge (MINWR), Florida

    NASA Technical Reports Server (NTRS)

    Nilsen, Frances M.; Dorsey, Jonathan E.; Long, Stephen E.; Schock, Tracey B.; Bowden, John A.; Lowers, Russell H.; Guillette, Louis J., Jr.

    2016-01-01

    Seasonal variation of mercury (Hg) is not well studied in free-ranging wildlife. Atmospheric deposition patterns of Hg have been studied in detail and have been modeled for both global and specific locations with great accuracy and correlates to environment impact. However, monitoring these trends in wildlife is complicated due to local environmental parameters (e.g., rainfall, humidity, pH, bacterial composition) that can affect the transformation of atmospheric Hg to the biologically available forms. Here, we utilized an abundant and healthy population of American alligators (Alligator mississippiensis) at Merritt Island National Wildlife Refuge (MINWR), FL, and assessed Hg burden in whole blood samples over a span of 7 years (2007 2014; n 174) in an effort to assess seasonal variation of total [Hg]. While the majority of this population is assumed healthy, 18 individuals with low body mass indices (BMI, defined in this study) were captured throughout the 7 year sampling period. These individual alligators exhibited [Hg] that were not consistent with the observed overall seasonal [Hg] variation, and were statistically different from the healthy population of alligators. The alligators with low BMI had elevated concentrations of Hg compared to their age/sex/season matched counterparts with normal BMI. Statistically significant differences were found between the winter and spring seasons for animals with normal BMI. The data in this report supports the conclusion that organismal total [Hg] do fluctuate directly with seasonal deposition rates as well as other seasonal environmental parameters, such as average rainfall and prevailing wind direction. This study highlights the unique environment of MINWR to permit annual assessment of apex predators, such as the American alligator, to determine detailed environmental impact of contaminants of concern.

  12. Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis).

    PubMed

    Owerkowicz, Tomasz; Elsey, Ruth M; Hicks, James W

    2009-05-01

    Recent palaeoatmospheric models suggest large-scale fluctuations in ambient oxygen level over the past 550 million years. To better understand how global hypoxia and hyperoxia might have affected the growth and physiology of contemporary vertebrates, we incubated eggs and raised hatchlings of the American alligator. Crocodilians are one of few vertebrate taxa that survived these global changes with distinctly conservative morphology. We maintained animals at 30 degrees C under chronic hypoxia (12% O(2)), normoxia (21% O(2)) or hyperoxia (30% O(2)). At hatching, hypoxic animals were significantly smaller than their normoxic and hyperoxic siblings. Over the course of 3 months, post-hatching growth was fastest under hyperoxia and slowest under hypoxia. Hypoxia, but not hyperoxia, caused distinct scaling of major visceral organs-reduction of liver mass, enlargement of the heart and accelerated growth of lungs. When absorptive and post-absorptive metabolic rates were measured in juvenile alligators, the increase in oxygen consumption rate due to digestion/absorption of food was greatest in hyperoxic alligators and smallest in hypoxic ones. Hyperoxic alligators exhibited the lowest breathing rate and highest oxygen consumption per breath. We suggest that, despite compensatory cardiopulmonary remodelling, growth of hypoxic alligators is constrained by low atmospheric oxygen supply, which may limit their food utilisation capacity. Conversely, the combination of elevated metabolism and low cost of breathing in hyperoxic alligators allows for a greater proportion of metabolised energy to be available for growth. This suggests that growth and metabolic patterns of extinct vertebrates would have been significantly affected by changes in the atmospheric oxygen level.

  13. Estimating trends in alligator populations from nightlight survey data

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, Frank J.; Dorazio, Robert M.; Rice, Kenneth G.; Cherkiss, Michael; Jeffery, Brian

    2011-01-01

    Nightlight surveys are commonly used to evaluate status and trends of crocodilian populations, but imperfect detection caused by survey- and location-specific factors makes it difficult to draw population inferences accurately from uncorrected data. We used a two-stage hierarchical model comprising population abundance and detection probability to examine recent abundance trends of American alligators (Alligator mississippiensis) in subareas of Everglades wetlands in Florida using nightlight survey data. During 2001–2008, there were declining trends in abundance of small and/or medium sized animals in a majority of subareas, whereas abundance of large sized animals had either demonstrated an increased or unclear trend. For small and large sized class animals, estimated detection probability declined as water depth increased. Detection probability of small animals was much lower than for larger size classes. The declining trend of smaller alligators may reflect a natural population response to the fluctuating environment of Everglades wetlands under modified hydrology. It may have negative implications for the future of alligator populations in this region, particularly if habitat conditions do not favor recruitment of offspring in the near term. Our study provides a foundation to improve inferences made from nightlight surveys of other crocodilian populations.

  14. Estimating trends in alligator populations from nightlight survey data

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, F.J.; Dorazio, R.M.; Rice, K.G.; Cherkiss, M.; Jeffery, B.

    2011-01-01

    Nightlight surveys are commonly used to evaluate status and trends of crocodilian populations, but imperfect detection caused by survey- and location-specific factors makes it difficult to draw population inferences accurately from uncorrected data. We used a two-stage hierarchical model comprising population abundance and detection probability to examine recent abundance trends of American alligators (Alligator mississippiensis) in subareas of Everglades wetlands in Florida using nightlight survey data. During 2001-2008, there were declining trends in abundance of small and/or medium sized animals in a majority of subareas, whereas abundance of large sized animals had either demonstrated an increased or unclear trend. For small and large sized class animals, estimated detection probability declined as water depth increased. Detection probability of small animals was much lower than for larger size classes. The declining trend of smaller alligators may reflect a natural population response to the fluctuating environment of Everglades wetlands under modified hydrology. It may have negative implications for the future of alligator populations in this region, particularly if habitat conditions do not favor recruitment of offspring in the near term. Our study provides a foundation to improve inferences made from nightlight surveys of other crocodilian populations. ?? 2011 US Government.

  15. Alligators and crocodiles as indicators for restoration of Everglades ecosystems

    USGS Publications Warehouse

    Mazzotti, Frank J.; Best, G. Ronnie; Brandt, Laura A.; Cherkiss, Michael S.; Jeffery, Brian M.; Rice, Kenneth G.

    2009-01-01

    Alligators and crocodiles integrate biological impacts of hydrological operations, affecting them at all life stages through three key aspects of Everglades ecology: (1) food webs, (2) diversity and productivity, and (3) freshwater flow. Responses of crocodilians are directly related to suitability of environmental conditions and hydrologic change. Correlations between biological responses and environmental conditions contribute to an understanding of species' status and trends over time. Positive or negative trends of crocodilian populations relative to hydrologic changes permit assessment of positive or negative trends in restoration. The crocodilian indicator uses monitoring parameters (performance measures) that have been shown to be both effective and efficient in tracking trends. The alligator component uses relative density (reported as an encounter rate), body condition, and occupancy rates of alligator holes; the crocodile component uses juvenile growth and hatchling survival. We hypothesize that these parameters are correlated with hydrologic conditions including depth, duration, timing, spatial extent and water quality. Salinity is a critical parameter in estuarine habitats. Assessments of parameters defined for crocodilian performance measures support these hypotheses. Alligators and crocodiles are the charismatic megafauna of the Everglades. They are both keystone and flagship species to which the public can relate. In addition, the parameters used to track trends are easy to understand. They provide answers to the following questions: How has the number of alligators or crocodiles changed? Are the animals fatter or thinner than they should be? Are the animals in the places (in terms of habitat and geography) where they should be? As surely as there is no other Everglades, no other single species defines the Everglades as does the American alligator. The Everglades is the only place in the world where both alligators and crocodiles exist. Crocodilians

  16. Ultrastructure of spermiogenesis in the American alligator, Alligator mississippiensis (Reptilia, Crocodylia, Alligatoridae).

    PubMed

    Gribbins, Kevin M; Siegel, Dustin S; Anzalone, Marla L; Jackson, Daniel P; Venable, Katherine J; Rheubert, Justin L; Elsey, Ruth M

    2010-10-01

    Testicular samples were collected to describe the ultrastructure of spermiogenisis in Alligator mississipiensis (American Alligator). Spermiogenesis commences with an acrosome vesicle forming from Golgi transport vesicles. An acrosome granule forms during vesicle contact with the nucleus, and remains posterior until mid to late elongation when it diffuses uniformly throughout the acrosomal lumen. The nucleus has uniform diffuse chromatin with small indices of heterochromatin, and the condensation of DNA is granular. The subacrosome space develops early, enlarges during elongation, and accumulates a thick layer of dark staining granules. Once the acrosome has completed its development, the nucleus of the early elongating spermatid becomes associated with the cell membrane flattening the acrosome vesicle on the apical surface of the nucleus, which aids in the migration of the acrosomal shoulders laterally. One endonuclear canal is present where the perforatorium resides. A prominent longitudinal manchette is associated with the nuclei of late elongating spermatids, and less numerous circular microtubules are observed close to the acrosome complex. The microtubule doublets of the midpiece axoneme are surrounded by a layer of dense staining granular material. The mitochondria of the midpiece abut the proximal centriole resulting in a very short neck region, and possess tubular cristae internally and concentric layers of cristae superficially. A fibrous sheath surrounds only the axoneme of the principal piece. Characters not previously described during spermiogenesis in any other amniote are observed and include (1) an endoplasmic reticulum cap during early acrosome development, (2) a concentric ring of endoplasmic reticulum around the nucleus of early to middle elongating spermatids, (3) a band of endoplasmic reticulum around the acrosome complex of late developing elongate spermatids, and (4) midpiece mitochondria that have both tubular and concentric layers of

  17. Concentrations of trace elements in American alligators (Alligator mississippiensis) from Florida, USA.

    PubMed

    Horai, Sawako; Itai, Takaaki; Noguchi, Takako; Yasuda, Yusuke; Adachi, Haruki; Hyobu, Yuika; Riyadi, Adi S; Boggs, Ashley S P; Lowers, Russell; Guillette, Louis J; Tanabe, Shinsuke

    2014-08-01

    Concentrations of 28 trace elements (Li, Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Tl, Hg, Pb, and Bi) in the livers of juvenile and adult American alligators inhabiting two central Florida lakes, Lake Apopka (LA), and Lake Woodruff National Wildlife Refuge (LW) and one lagoon population located in Merritt Island National Wildlife Refuge (MINWR; NASA), were determined. In juveniles from MINWR, concentrations of nine elements (Li, Fe, Ni, Sr, In, Sb, Hg, Pb and Bi) were significantly higher, whereas six elements (V, Fe, As, Sr, Hg and Bi) were elevated in adults (p<0.05) obtained from MINWR. Significant enrichment of some trace elements in adults, relative to juveniles, was observed at all three sampling areas. Specifically, Fe, Pb and Hg were significantly elevated in adults when compared to juveniles, suggesting age-dependent accumulation of these elements. Further, As, Se and Sn showed the same trend but only in animals collected from MINWR. Mean Fe concentrations in the livers of adults from LA, LW and MINWR were 1770 μg g(-1) DW, 3690 μg g(-1) DW and 5250 μg g(-1) DW, respectively. More than half of the adult specimens from LW and MINWR exhibited elevated hepatic Fe concentrations that exceed the threshold value for toxic effects in donkey, red deer and human. These results prompted us to express our concern on possible exposure and health effects in American alligators by some trace elements derived from NASA activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Isolation and determination of the primary structure of a lectin protein from the serum of the American alligator (Alligator mississippiensis).

    PubMed

    Darville, Lancia N F; Merchant, Mark E; Maccha, Venkata; Siddavarapu, Vivekananda Reddy; Hasan, Azeem; Murray, Kermit K

    2012-02-01

    Mass spectrometry in conjunction with de novo sequencing was used to determine the amino acid sequence of a 35kDa lectin protein isolated from the serum of the American alligator that exhibits binding to mannose. The protein N-terminal sequence was determined using Edman degradation and enzymatic digestion with different proteases was used to generate peptide fragments for analysis by liquid chromatography tandem mass spectrometry (LC MS/MS). Separate analysis of the protein digests with multiple enzymes enhanced the protein sequence coverage. De novo sequencing was accomplished using MASCOT Distiller and PEAKS software and the sequences were searched against the NCBI database using MASCOT and BLAST to identify homologous peptides. MS analysis of the intact protein indicated that it is present primarily as monomer and dimer in vitro. The isolated 35kDa protein was ~98% sequenced and found to have 313 amino acids and nine cysteine residues and was identified as an alligator lectin. The alligator lectin sequence was aligned with other lectin sequences using DIALIGN and ClustalW software and was found to exhibit 58% and 59% similarity to both human and mouse intelectin-1. The alligator lectin exhibited strong binding affinities toward mannan and mannose as compared to other tested carbohydrates.

  19. Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis

    PubMed Central

    Hansen, Anne

    2007-01-01

    Background The nasal cavity of all vertebrates houses multiple chemosensors, either innervated by the Ist (olfactory) or the Vth (trigeminal) cranial nerve. Various types of receptor cells are present, either segregated in different compartments (e.g. in rodents) or mingled in one epithelium (e.g. fish). In addition, solitary chemosensory cells have been reported for several species. Alligators which seek their prey both above and under water have only one nasal compartment. Information about their olfactory epithelium is limited. Since alligators seem to detect both volatile and water-soluble odour cues, I tested whether different sensory cell types are present in the olfactory epithelium. Results Electron microscopy and immunocytochemistry were used to examine the sensory epithelium of the nasal cavity of the American alligator. Almost the entire nasal cavity is lined with olfactory (sensory) epithelium. Two types of olfactory sensory neurons are present. Both types bear cilia as well as microvilli at their apical endings and express the typical markers for olfactory neurons. The density of these olfactory neurons varies along the nasal cavity. In addition, solitary chemosensory cells innervated by trigeminal nerve fibres, are intermingled with olfactory sensory neurons. Solitary chemosensory cells express components of the PLC-transduction cascade found in solitary chemosensory cells in rodents. Conclusion The nasal cavity of the American alligator contains two different chemosensory systems incorporated in the same sensory epithelium: the olfactory system proper and solitary chemosensory cells. The olfactory system contains two morphological distinct types of ciliated olfactory receptor neurons. PMID:17683564

  20. Penile anatomy and hypotheses of erectile function in the American alligator (Alligator mississippiensis): muscular eversion and elastic retraction.

    PubMed

    Kelly, D A

    2013-03-01

    The intromittent organs of most amniotes contain variable-volume hydrostatic skeletons that are stored in a flexible state and inflate with fluid before or during copulation. However, the penis in male crocodilians is notable because its shaft does not seem to change either its shape or bending stiffness as blood enters its vascular spaces before copulation. Here I report that crocodilians may have evolved a mechanism for penile shaft erection that does not require inflation and detumescence. Dissections of the cloaca in sexually mature male American alligators (Alligator mississippiensis) show that the cross section of the proximal shaft of the alligator penis contains dense collagenous tissues that do not significantly change shape when fluid is added to the central vascular space. The large amount of collagen in the wall and central space of the alligator penis stiffen the structure so it can be simply everted for copulation and rapidly retracted at its completion. Because no muscles insert directly onto the penis, eversion and retraction must be produced indirectly. My results suggest that the contraction of paired levator cloacae muscles around the anterior end of the cloaca rotates the penis out of the cloacal opening and strains the ligamentum rami that connect the base of the penis to the ischia. When the cloacal muscles relax, the elastic recoil of the ligamentum rami can return the penis to its original position inside the cloaca. Copyright © 2012 Wiley Periodicals, Inc.

  1. Chronic hypercapnic incubation increases relative organ growth and reduces blood pressure of embryonic American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Crossley, Dane A

    2015-04-01

    Reptilian nests can experience natural hypoxic and hypercapnic conditions. We incubated alligator eggs at a female-only producing temperature (30°C) in three conditions: 21% O2/0.04% CO2, 21% O2/3.5% CO2 and 21% O2/7% CO2. Alligator embryos chronically incubated in high CO2 were markedly hypotensive (blood pressure reduced by 46%) and had relatively (mass-specific) enlarged hearts (dry mass increased by 20%), lungs (dry mass increased by 17%), and kidneys (dry mass increased by 14%). This study is the first to chronically incubate reptilian eggs in hypercapnia and suggests that high CO2 alters the cardiovascular phenotype of alligator embryos (low blood pressure, relatively enlarged hearts), as well as the relative size of the organs primarily responsible for acid base balance, lungs and kidneys. The lungs and kidneys are largely non-functional during embryonic development, and the embryonic phenotype of increased relative mass may be a predictive-adaptation to metabolic or respiratory acidosis, such as during exercise or high respiratory CO2. This study demonstrates that phenotypic plasticity of alligator embryos incubated in high CO2 may result in either preferential organ growth, or maintenance of organ growth with reduced somatic growth.

  2. Computed tomography of granulomatous pneumonia with oxalosis in an American alligator (Alligator mississippiensis) associated with Metarhizium anisopliae var anisopliae.

    PubMed

    Hall, Natalie H; Conley, Kenneth; Berry, Clifford; Farina, Lisa; Sigler, Lynne; Wellehan, James F X; Roehrl, Michael H A; Heard, Darryl

    2011-12-01

    An 18-yr-old, male, albino, American alligator (Alligator mississippiensis) was evaluated for decreased appetite and abnormal buoyancy. Computed tomography (CT) of the coelomic cavity showed multifocal mineral and soft tissue attenuating pulmonary masses consistent with pulmonary fungal granulomas. Additionally, multifocal areas of generalized, severe emphysema and pulmonary and pleural thickening were identified. The alligator was euthanized and necropsy revealed severe fungal pneumonia associated with oxalosis. Metarhizium anisopliae var. anisopliae was cultured from lung tissue and exhibited oxalate crystal formation in vitro. Crystals were identified as calcium oxalate monohydrate by X-ray powder defractometry. Fungal identification was based on morphology, including tissue sporulation, and DNA sequence analysis. This organism is typically thought of as an entomopathogen. Clinical signs of fungal pneumonia in nonavian reptiles are often inapparent until the disease is at an advanced stage, making antemortem diagnosis challenging. This case demonstrates the value of CT for pulmonary assessment and diagnosis of fungal pneumonia in the American alligator. Fungal infection with associated oxalosis should not be presumed to be aspergillosis.

  3. Ultrasonography of reproductive structures and hormonal correlates of follicular development in female American alligators, Alligator mississippiensis, in southwest Louisiana.

    PubMed

    Lance, Valentine A; Rostal, David C; Elsey, Ruth M; Trosclair, Phillip L

    2009-07-01

    Ultrasonography has been used effectively to study reproduction in a variety of reptile species, but its application to crocodilians has been relatively limited. We present results from a study testing the efficacy of using ultrasonography to monitor reproduction in the American alligator, Alligator mississippiensis. Ultrasound results were then compared with plasma hormone levels. A total of 124 females were examined during March, April, May, and early June (2001-2003). Ultrasound results were validated on a series of reproductive females (n=14) necropsied for other studies. Previtellogenic follicles, vitellogenic follicles, recently shelled eggs, fully developed well-calcified eggs, and atretic follicles were readily discernible with ultrasound in mature females. Reproductive structures were observed in 57 females of which 43 were actively reproductive, while 14 were non-reproductive, but contained large atretic follicles from prior years. Oviducts were discernible in females with eggs. Ovarian state was also correlated with hormone levels. These results are in agreement with previous studies that showed that 50% or less of the adult female alligator population is reproductively active in a given year. Ultrasonography can be used to make an accurate assessment of reproductive condition in wild alligator populations.

  4. Contribution of the diaphragmaticus muscle to vital capacity in fasting and post-prandial American alligators (Alligator mississippiensis).

    PubMed

    Uriona, T J; Farmer, C G

    2006-11-01

    The importance of the diaphragmaticus muscle to vital capacity was investigated in juvenile American alligators by transection of this muscle. In both fasting and post-prandial animals a pneumotach was used to study vital capacity that was stimulated by either a hypercapnic-anoxic gas mixture or a hypercapnic-normoxic gas mixture in two types of control groups of animals (a shamoperated group and a group receiving no treatment) and in the experimental (transected) group. Transection did not significantly reduce vital capacity or affect time of inspiration or expiration in fasted animals. For both the experimental and control groups vital capacity was greatly reduced in post-prandial animals compared to the fasting state. Furthermore, alligators with a transected diaphragmaticus muscle showed a 16-18% greater drop in vital capacity in the post-prandial state than did alligators with an intact diaphragmaticus muscle. The post-prandial decrease in vital capacity for alligators with a transected diaphragmaticus occurred concomitantly with a significant increase in time to inspire and a decrease in maximum rate of inspiration when compared to control animals. The results from this study suggest that the diaphragmaticus muscle plays an important role in enabling large volumes of oxygen to be taken into the lungs in the post-prandial state.

  5. Sex-steroid and thyroid hormone concentrations in juvenile alligators (Alligator mississippiensis) from contaminated and reference lakes in Florida, USA

    USGS Publications Warehouse

    Grain, D.A.; Guillette, L.J.; Pickford, D.B.; Percival, H.F.; Woodward, A.R.

    1998-01-01

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-171?? (E2), testosterone (T), triiodothyronine (T3), and thyroxine (T4) in juvenile alligators (60-140 cm total length) from two contaminated lakes and one reference lake in Florida. First, the data were analyzed by comparing hormone concentrations among males and females from the different lakes. Whereas there were no differences in plasma E2 concentrations among animals of the three lakes, male alligators from the contaminated lakes (Lake Apopka and Lake Okeechobee) had significantly lower plasma T concentrations compared 10 males from the reference take (Lake Woodruff). Concentrations of thyroid hormones also differed in animals of the three lakes, with T4 concentrations being elevated in Lake Okeechobee males compared to Lake Woodruff males. Second, the relationship between body size and hormone concentration was examined using regression analysis. Most notably for steroid hormones, no clear relationship was detected between E2 and total length in Apopka females (r2 0.09, p = 0.54) or between T and total length in Apopka males (r2 = 0.007, p = 0.75). Females from Apopka (r2 = 0.318, p = 0.09) and Okeechobee (r2 = 0.222, p = 0.09) exhibited weak correlations between T3 and total length. Males from Apopka (r2 = 0.015, p = 0.66) and Okeechobee (r2 = 0.128, p = 0.19) showed no correlation between T4 and total length. These results indicate: some of the previously reported abnormalities in steroid hormones of hatchling alligators persist, at least, through the juvenile years; steroid and thyroid hormones are related to body size in juvenile alligators from the reference lake, whereas alligators living in lakes Apopka and Okeechobee experience alterations in circulating thyroid and steroid

  6. Low mitochondrial DNA variation among American alligators and a novel non-coding region in crocodilians.

    PubMed

    Glenn, Travis C; Staton, Joseph L; Vu, Alex T; Davis, Lisa M; Bremer, Jaime R Alvarado; Rhodes, Walter E; Brisbin, I Lehr; Sawyer, Roger H

    2002-12-15

    We analyzed 1317-1823 base pairs (bp) of mitochondrial DNA sequence beginning in the 5' end of cytochrome b (cyt b) and ending in the central domain of the control region for 25 American alligators (Alligator mississippiensis) and compared these to a homologous sequence from a Chinese alligator (A. sinensis). Both species share a non-coding spacer between cyt b and tRNA(Thr). Chinese alligator cyt b differs from that of the American alligator by 17.5% at the nucleotide level and 13.8% for inferred amino acids, which is consistent with their presumed ancient divergence. Only two cyt b haplotypes were detected among the 25 American alligators (693-1199 bp surveyed), with one haplotype shared among 24 individuals. One alligator from Mississippi differed from all other alligators by a single silent substitution. The control region contained only slightly more variation among the 25 American alligators, with two variable positions (624 bp surveyed), yielding three haplotypes with 22, two, and one individuals in each of these groups. Previous genetic studies examining allozymes and the proportion of variable microsatellite DNA loci also found low levels of genetic diversity in American alligators. However, in contrast with allozymes, microsatellites, and morphology, the mtDNA data shows no evidence of differentiation among populations from the extremes of the species range. These results suggest that American alligators underwent a severe population bottleneck in the late Pleistocene, resulting in nearly homogenous mtDNA among all American alligators today. Copyright 2002 Wiley-Liss, Inc.

  7. Spatial and temporal variability in estuary habitat use by American alligators

    USGS Publications Warehouse

    Fujisaki, Ikuko; Hart, Kristen M.; Cherkiss, Michael S.; Mazzotti, Frank J.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Brandt, Laura A.

    2016-01-01

    Estuarine habitat occupied by Alligator mississippiensis, a primarily freshwater species, is spatially and temporally heterogeneous largely due to a salinity gradient that fluctuates. Using long-term night light survey data, we examined seasonal patterns in alligators’ habitat use by size classes in midstream and downstream estuary zones of Shark River, Everglades National Park, in southern Florida. We observed predominantly large-sized alligators (total length ≥ 1.75 m); observations of alligators in the small size classes (0.5 m ≤ total length < 1.25 m) were rare especially in the higher-salinity downstream zone. The density of alligators in the downstream zone was lower than that of the midstream zone during the dry season when salinity increases due to reduced precipitation. Conversely, the density of the large size alligators was higher in the downstream zone than in the midstream zone during the wet season, likely because of reduced salinity. We also found a significant declining trend over time in the number of alligators in the dry season, which coincides with the reported decline in alligator relative density in southern Florida freshwater wetlands. Our results indicated high adaptability of alligators to the fluctuating habitat conditions. Use of estuaries by alligators is likely driven in part by physiology and possibly by reproductive cycle, and our results supported their opportunistic use of estuary habitat and ontogenetic niche shifts.

  8. Detection of Antibodies to a Pathogenic Mycoplasma in American Alligators (Alligator mississippiensis), Broad-Nosed Caimans (Caiman latirostris), and Siamese Crocodiles (Crocodylus siamensis)

    PubMed Central

    Brown, D. R.; Schumacher, I. M.; Nogueira, M. F.; Richey, L. J.; Zacher, L. A.; Schoeb, T. R.; Vliet, K. A.; Bennett, R. A.; Jacobson, E. R.; Brown, M. B.

    2001-01-01

    An epidemic of pneumonia with fibrinous polyserositis and multifocal arthritis emerged in captive American alligators (Alligator mississippiensis) in Florida, United States, in 1995. Mycoplasma alligatoris sp. nov. was cultured from multiple organs, peripheral blood, synovial fluid, and cerebrospinal fluid of affected alligators. In a subsequent experimental inoculation study, the Henle-Koch-Evans postulates were fulfilled for M. alligatoris as the etiological agent of fatal mycoplasmosis of alligators. That finding was remarkable because mycoplasmal disease is rarely fatal in animals. An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies produced by alligators in response to M. alligatoris exposure was developed by using plasma obtained from naturally infected alligators during the original epidemic. The assay was validated by using plasma obtained during an experimental dose-response study and applied to analyze plasma obtained from captive and wild crocodilian species. The ELISA reliably detected alligator seroconversion (P < 0.05) beginning 6 weeks after inoculation. The ELISA also detected seroconversion (P < 0.05) in the relatively closely related broad-nosed caiman Caiman latirostris and the relatively distantly related Siamese crocodile Crocodylus siamensis following experimental inoculation with M. alligatoris. The ELISA may be used to monitor exposure to the lethal pathogen M. alligatoris among captive, repatriated, and wild crocodilian species. PMID:11136785

  9. Validation and use of an indirect enzyme-linked immunosorbent assay for detection of antibodies to West Nile virus in American Alligators (Alligator mississippiensis) in Florida.

    PubMed

    Jacobson, Elliott R; Johnson, April J; Hernandez, Jorge A; Tucker, Sylvia J; Dupuis, Alan P; Stevens, Robert; Carbonneau, Dwayne; Stark, Lillian

    2005-01-01

    In October 2002, West Nile virus (WNV) was identified in farmed American alligators (Alligator mississippiensis) in Florida showing clinical signs and having microscopic lesions indicative of central nervous system disease. To perform seroepidemiologic studies, an indirect enzyme-linked immunosorbent assay (ELISA) was developed to determine exposure of captive and wild alligators to WNV. To validate the test, a group of WNV-seropositive and -seronegative alligators were identified at the affected farm using hemagglutination inhibition (HAI) and the plaque reduction neutralization test (PRNT). The indirect ELISA utilized a rabbit anti-alligator immunoglobulins polyclonal antibody as the secondary antibody, and inactivated WNV-infected Vero cells were used as the coating antigen. For all samples (n=58), the results of the ELISA were consistent with the HAI and PRNT findings. Plasma was collected from 669 free-ranging alligators from 21 sites across Florida in April and October 2003. Four samples collected in April and six in October were positive for WNV antibodies using HAI, PRNT, and the indirect ELISA. This indicated that wild alligators in Florida have been exposed to WNV. These findings can be used as a baseline for future surveys.

  10. Detection of antibodies to a pathogenic mycoplasma in American alligators (Alligator mississippiensis), broad-nosed Caimans (Caiman latirostris), and Siamese crocodiles (Crocodylus siamensis).

    PubMed

    Brown, D R; Schumacher, I M; Nogueira, M F; Richey, L J; Zacher, L A; Schoeb, T R; Vliet, K A; Bennett, R A; Jacobson, E R; Brown, M B

    2001-01-01

    An epidemic of pneumonia with fibrinous polyserositis and multifocal arthritis emerged in captive American alligators (Alligator mississippiensis) in Florida, United States, in 1995. Mycoplasma alligatoris sp. nov. was cultured from multiple organs, peripheral blood, synovial fluid, and cerebrospinal fluid of affected alligators. In a subsequent experimental inoculation study, the Henle-Koch-Evans postulates were fulfilled for M. alligatoris as the etiological agent of fatal mycoplasmosis of alligators. That finding was remarkable because mycoplasmal disease is rarely fatal in animals. An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies produced by alligators in response to M. alligatoris exposure was developed by using plasma obtained from naturally infected alligators during the original epidemic. The assay was validated by using plasma obtained during an experimental dose-response study and applied to analyze plasma obtained from captive and wild crocodilian species. The ELISA reliably detected alligator seroconversion (P < 0.05) beginning 6 weeks after inoculation. The ELISA also detected seroconversion (P < 0.05) in the relatively closely related broad-nosed caiman Caiman latirostris and the relatively distantly related Siamese crocodile Crocodylus siamensis following experimental inoculation with M. alligatoris. The ELISA may be used to monitor exposure to the lethal pathogen M. alligatoris among captive, repatriated, and wild crocodilian species.

  11. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point at...

  12. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order Crocodylia...

  13. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point at...

  14. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order Crocodylia...

  15. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order Crocodylia...

  16. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point at...

  17. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point at...

  18. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point at...

  19. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order Crocodylia...

  20. Survival of young American alligators on a Florida lake

    USGS Publications Warehouse

    Woodward, A.R.; Hines, T.C.; Abercrombie, C.L.; Nichols, J.D.

    1987-01-01

    A capture-recapture study was conducted on Orange Lake, Florida, from 1979 through 1984 to estimate survival rates of young in an American alligator (Alligator mississippiensis) populations. Hatchlings remained together in sibling groups (pods) for at least their 1st year and then began to disperse during their 2nd spring and summer. Mortality through mid-November of their 1st year was negligible. Jolly-Seber (JS) survival estimates of hatchlings for 6 and 12 months were 76 and 41%, respectively. The 2-year JS estimate for the 1980 cohort was 8%. Minimum-Known-Alive (MKA) survival values were 72 and 46% of JS estimates for 6 months and 1 year of age. Survival during the 2nd 6 months of life (spring-summer) tended to be lower than survival during the 1st 6 months (fall-winter).

  1. A new alligator-clip compound for molecular electronics

    NASA Astrophysics Data System (ADS)

    Jacob, Timo; Blanco, Mario; Goddard, William A.

    2004-06-01

    We used the B3LYP flavor of density functional calculations to study new alligator-clip compounds for molecular electronics with platinum electrodes. First, with commonly used S-based linkage molecule 3-methyl-1,2-dithiolane (MDTL) we find that after chemisorption on Pt(1 1 1) the most stable structure is ring-opened with a binding energy of 32.44 kcal/mol. Among several alternative alligator-clip compounds we find that P-based molecules lead to much higher binding energies. For the ring-closed structure of 3-methyl-1,2-diphospholane (MDPL) a binding energy of 47.72 kcal/mol was calculated and even 54.88 kcal/mol for the ring-opened molecule. Thus, MDPL provides a more stable link to the metal surface and might increase the conductance.

  2. IgH loci of American alligator and saltwater crocodile shed light on IgA evolution.

    PubMed

    Magadán-Mompó, Susana; Sánchez-Espinel, Christian; Gambón-Deza, Francisco

    2013-07-01

    Immunoglobulin loci of two representatives of the order Crocodylia were studied from full genome sequences. Both Alligator mississippiensis and Crocodylus porosus have 13 genes for the heavy chain constant regions of immunoglobulins. The IGHC locus contains genes encoding four immunoglobulins M (IgM), one immunoglobulin D (IgD), three immunoglobulins A (IgA), three immunoglobulins Y (IgY), and two immunoglobulins D2 (IgD2). IgA and IgD2 genes were found in reverse transcriptional orientation compared to the other Ig genes. The IGHD gene contains 11 exons, four of which containing stop codons or sequence alterations. As described in other reptiles, the IgD2 is a chimeric Ig with IgA- and IgD-related domains. This work clarifies the origin of bird IgA and its evolutionary relationship with amphibian immunoglobulin X (IgX) as well as their links with mammalian IgA.

  3. Water Hyacinths and Alligator Weeds for Final Filtration of Sewage

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

    1976-01-01

    The potential of water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxerides) (Mart.) Griesb. as secondary and tertiary filtration systems for domestic sewage was demonstrated. These two vascular aquatic plants reduced the suspended solids, total Kjeldahl nitrogen, total phosphorus, BOD sub 5, and total organic carbon levels in domestic sewage from 60 percent to 98 percent within a two week period. These plants grown in domestic sewage were also free of toxic levels of trace heavy metals.

  4. Similarity of osmoregulatory capacity in coastal and inland alligator gar.

    PubMed

    Allen, Peter J; Haukenes, Alf; Lochmann, Steve E

    2017-07-01

    The alligator gar Atractosteus spatula is a primitive fish species, occupying a wide range of temperature and salinity habitats. Long-distance movements are limited, leading to genetic differentiation between inland and coastal populations. Unknown is whether physiological capacity differs between geographically separated populations, particularly for traits important to osmoregulation in saline environments. Alligator gar from inland and coastal populations were reared in a similar environment and exposed to temperature (10, 30°C) and salinity (0, 20ppt) extremes to determine whether iono- and osmoregulatory ability differed between populations. There were few differences in osmoregulatory ability between populations, with similar gill, blood and gastrointestinal tract osmoregulatory parameters. Blood plasma osmolality, ion concentrations, intestinal pH and bicarbonate base concentrations, intestinal fluid osmolality, ion concentrations and gill Na(+), K(+)-ATPase (NKA) activity were similar between populations. Notably, gar from both populations did not osmoregulate well at low temperature and high salinity, with elevated plasma osmolality and ion concentrations, low gill NKA, and little evidence of gastrointestinal tract contribution to ionic and base regulation based on a lack of intestinal fluid and low base content. Therefore, the hypothesis that coastal gar would have improved osmotic regulatory ability in saline environments as compared to inland alligator gar was not supported, suggesting physiological capacity may be retained in primitive species possibly due to its importance to their persistence through time. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Sperm storage in the oviduct of the American alligator.

    PubMed

    Gist, Daniel H; Bagwill, April; Lance, Valentine; Sever, David M; Elsey, Ruth M

    2008-12-01

    Oviducts of the American alligator (Alligator mississippiensis) were examined histologically for the presence of stored sperm. Two regions containing sperm were identified, one at the junction of the posterior uterus and the vagina (UVJ) and the other at the junction of the tube and isthmus (TIJ). In these areas, sperm were found in the lumina of oviductal glands. The glands in these areas of the oviduct are diffuse and shallow and appear to allow better access to sperm than glands located elsewhere. Histochemically, the glands of the UVJ reacted weakly for carbohydrates and proteins, whereas those of the TIJ reacted strongly for these same two components, secretions of which are associated with sperm storage structures in other reptiles. Sperm were not in contact with the glandular epithelium, and glands at the UVJ contained more sperm than those at the TIJ. Oviductal sperm storage was observed not only in recently mated females but in all females possessing uterine eggs as well as all females known to be associated with a nest. We conclude that female alligators are capable of storing sperm in their oviductal glands, but not from one year to the next. (c) 2008 Wiley-Liss, Inc.

  6. Mathematical models for growth in alligator (Alligator mississippiensis) embryos developing at different incubation temperatures.

    PubMed

    Bardsley, W G; Ackerman, R A; Bukhari, N A; Deeming, D C; Ferguson, M W

    1995-08-01

    A variety of model-based (growth models) and model-free (cubic splines, exponentials) equations were fitted using weighted-nonlinear least squares regression to embryonic growth data from Alligator mississippiensis eggs incubated at 30 and 33 degrees C. Goodness of fit was estimated using a chi 2 on the sum of squared, weighted residuals, and run and sign tests on the residuals. One of the growth models used (Preece & Baines, 1978) was found to be superior to the classical growth models (exponential, monomolecular, logistic, Gompertz, von Bertalanffy) and gave an adequate fit to all longitudinal measures taken from the embryonic body and embryonic mass. However, measurements taken from the head could not be fitted by growth models but were adequately fitted by weighted least squares cubic splines. Data for the stage of development were best fitted by a sum of 2 exponentials with a transition point. Comparison of the maximum growth rates and parameter values, indicated that the growth data at 30 degrees C could be scaled to 33 degrees C to multiplying the time by a scaling factor of 1.2. This is equivalent to a Q10 of about 1.86 or, after solving the Arrhenius equation, an E++ of 46.9 kJmol-1. This may be interpreted as indicating a common rate-limiting step in development at the 2 temperatures.

  7. Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites.

    PubMed

    Tellez, Marisa; Merchant, Mark

    2015-01-01

    Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.

  8. WILDLIFE - ALLIGATOR STROLLS FROM TURN BASIN TO LC 39 PRESS SITE GRANDSTAND

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A 12-foot alligator worked his way up from the turn basin at Press Site 39 to the grandstand seats. The toothy reptile was later wrangled by wildlife trappers who relocated him to a less populated area on KSC. The alligator is one of approximately 4,000 on KSC/Merritt Island National Wildlife Refuge.

  9. PLASMA STEROID CONCENTRATIONS IN RELATION TO SIZE AND AGE IN JUVENILE ALLIGATORS FROM TWO FLORIDA LAKES.

    EPA Science Inventory

    Previous studies have reported a number of physiological differences among juvenile alligators from two well-studied populations (Lake Apopka and Lake Woodruff) in north central Florida. These studies obtained alligators of similar size from each lake under the assumption that th...

  10. WILDLIFE - ALLIGATOR STROLLS FROM TURN BASIN TO LC 39 PRESS SITE GRANDSTAND

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A 12-foot alligator worked his way up from the turn basin at Press Site 39 to the grandstand seats. The toothy reptile was later wrangled by wildlife trappers who relocated him to a less populated area on KSC. The alligator is one of approximately 4,000 on KSC/Merritt Island National Wildlife Refuge.

  11. Parental exposure to pesticides and poor clutch viability in American alligators.

    PubMed

    Rauschenberger, R Heath; Wiebe, Jon J; Sepúlveda, Maria S; Scarborough, Janet E; Gross, Timothy S

    2007-08-01

    In central Florida, alligators (Alligator mississippiensis) inhabiting lakes contaminated with organochlorine pesticides (OCPs) produce eggs that have high OCP concentrations and low clutch viability (proportion of eggs in a clutch that yield a live hatchling) compared to those from less contaminated lakes (reference lakes). However, a clear dose-response relationship has not been established between OCPs and poor clutch viability. In order to better elucidate a cause and effect relationship between OCP exposure and clutch viability, we conducted concurrent field and laboratory studies. Our field study reaffirmed that eggs of wild alligators from OCP-contaminated lakes and wetlands continue to have lower clutch viability and higher OCP burdens than eggs from reference lakes. Our field study also demonstrated that OCP egg burdens were strongly correlated with clutch viability for some of the OCP-contaminated sites, but not all. To better test causal relationships, a parental exposure study was conducted using captive adult alligators. Our laboratory study demonstrated that dietary exposure of captive alligators to an ecologically relevant OCP mixture caused alligators to produce eggs with higher OCP burdens and reduced clutch viability, as compared to the captive-control population. The experimentally induced egg burdens and clutch viability reductions were similar to those of wild alligators from OCP-contaminated sites. Our field and laboratory results suggest parental OCP exposure may be contributing to low clutch viability in wild alligators inhabiting OCP-contaminated habitats, raising some concern for endangered crocodilians living in OCP-contaminated habitats.

  12. PLASMA STEROID CONCENTRATIONS IN RELATION TO SIZE AND AGE IN JUVENILE ALLIGATORS FROM TWO FLORIDA LAKES.

    EPA Science Inventory

    Previous studies have reported a number of physiological differences among juvenile alligators from two well-studied populations (Lake Apopka and Lake Woodruff) in north central Florida. These studies obtained alligators of similar size from each lake under the assumption that th...

  13. Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites

    PubMed Central

    Tellez, Marisa; Merchant, Mark

    2015-01-01

    Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment. PMID:26555363

  14. A new species of leech of the genus Placobdella (Hirudinida, Glossiphoniidae) from the American alligator (Alligator mississippiensis) in Mississippi, USA.

    PubMed

    Richardson, Dennis J; Moser, William E; Hammond, Charlotte I; Lazo-Wasem, Eric A; McAllister, Chris T; Pulis, Eric E

    2017-01-01

    To date, the only species of leech reported from the American Alligator, Alligator mississippiensis is Placobdella multilineata. Seven specimens of a previously undescribed species of Placobdella were collected from the feet and lower jaw of a single female alligator from the Pascagoula River Wildlife Management Area, George County, Mississippi. The new species was named Placobdella siddalli Richardson & Moser, sp. n., in honor of the contributions of Dr. Mark Siddall to our understanding of the biology of leeches. Placobdella siddalli Richardson & Moser is similar to other papillated members of the genus Placobdella, but differs from Placobdella ali Hughes & Siddall, 2007, Placobdella rugosa (Verrill, 1874), Placobdella multilineata Moore, 1953, and Placobdella papillifera (Verrill, 1872) in coloration, papillation, ventral striping, and in the possession of a relatively large caudal sucker. In addition, molecular comparison of 626 nucleotides of CO-I between the new species and other papillated leeches (P. ali, P. multilineata, Placobdella ornata, P. papillifera, P. rugosa) revealed interspecific differences of 14.0-18.0% (88-113 nucleotides).

  15. Gastric nematode diversity between estuarine and inland freshwater populations of the American alligator (Alligator mississippiensis, daudin 1802), and the prediction of intermediate hosts

    PubMed Central

    Tellez, Marisa; Nifong, James

    2014-01-01

    We examined the variation of stomach nematode intensity and species richness of Alligator mississippiensis from coastal estuarine and inland freshwater habitats in Florida and Georgia, and integrated prey content data to predict possible intermediate hosts. Nematode parasitism within inland freshwater inhabiting populations was found to have a higher intensity and species richness than those inhabiting coastal estuarine systems. This pattern potentially correlates with the difference and diversity of prey available between inland freshwater and coastal estuarine habitats. Increased consumption of a diverse array of prey was also correlated with increased nematode intensity in larger alligators. Parasitic nematodes Dujardinascaris waltoni, Brevimulticaecum tenuicolle, Ortleppascaris antipini, Goezia sp., and Contracaecum sp. were present in alligators from both habitat types. Dujardinascaris waltoni, B. tenuicolle, and O. antipini had a significantly higher abundance among inland inhabiting alligators than hosts from estuarine populations. Our findings also suggest that host specific nematode parasites of alligators may have evolved to infect multiple intermediate hosts, particularly fishes, crabs, and turtles, perhaps in response to the opportunistic predatory behaviors of alligators. PMID:25426417

  16. Growth plate formation and development in alligator and mouse metapodials: evolutionary and functional implications.

    PubMed

    Reno, Philip L; Horton, Walter E; Elsey, Ruth M; Lovejoy, C Owen

    2007-05-15

    Mammalian metapodials (metacarpals and metatarsals), unlike most long bones, form a single growth plate, and undergo longitudinal growth at only one end. The growth dynamics of non-mammalian tetrapod metapodials have not been systematically examined in order to determine if unidirectional growth is unique to mammals. Here we compare murine metapodial ossification in growth stages that parallel those of embryonic, juvenile and subadult American alligators (Alligator mississippiensis). Safranin O staining was used for qualitative histology, and chondrocyte differentiation and proliferation were assessed via immunohistochemistry for type X collagen and proliferative cell nuclear antigen (PCNA). We establish that growth plates form at both ends of alligator metapodials and are maintained in the subadult. PCNA results show that alligators and mice share common patterns of chondrocyte proliferation during growth plate formation. In addition, while alligators and mice differ initially in the degree of organization and pace of chondrocyte differentiation, these parameters are largely similar in established growth plates. However, the replacement of cartilage by bone is highly irregular throughout growth in the alligator, in contrast to the more uniform process in the mouse. These results indicate that while alligators and mammals share common mechanisms of chondrocyte regulation, they differ substantially in their processes of ossification. Phylogenetic analysis indicates that the direct ossification of one epiphysis and reliance on a single growth plate is a derived character (synapomorphy) in therian mammals and likely indicates an adaptation for erect quadrupedal gait.

  17. Influence of tissue, age, and environmental quality on DNA methylation in Alligator mississippiensis.

    PubMed

    Parrott, Benjamin B; Bowden, John A; Kohno, Satomi; Cloy-McCoy, Jessica A; Hale, Matthew D; Bangma, Jacqueline T; Rainwater, Thomas R; Wilkinson, Phillip M; Kucklick, John R; Guillette, Louis J

    2014-01-01

    Epigenetic modifications are key mediators of the interactions between the environment and an organism's genome. DNA methylation represents the best-studied epigenetic modification to date and is known to play key roles in regulating transcriptional activity and promoting chromosome stability. Our laboratory has previously demonstrated the utility of the American alligator (Alligator mississippiensis) as a sentinel species to investigate the persistent effects of environmental contaminant exposure on reproductive health. Here, we incorporate a liquid chromatography-tandem mass spectrometry method to directly measure the total (global) proportion of 5-methyl-2'-deoxycytidine (5mdC) in ovarian and whole blood DNA from alligators. Global DNA methylation in ovaries was significantly elevated in comparison with that of whole blood. However, DNA methylation appeared similar in juvenile alligators reared under controlled laboratory conditions but originating from three sites with dissimilar environmental qualities, indicating an absence of detectable site-of-origin effects on persistent levels of global 5mdC content. Analyses of tissues across individuals revealed a surprising lack of correlation between global methylation levels in blood and ovary. In addition, global DNA methylation in blood samples from juvenile alligators was elevated compared with those from adults, suggesting that age, as observed in mammals, may negatively influence global DNA methylation levels in alligators. To our knowledge, this is the first study examining global levels of DNA methylation in the American alligator and provides a reference point for future studies examining the interplay of epigenetics and environmental factors in a long-lived sentinel species.

  18. Dry years decrease abundance of American alligators in the Florida Everglades

    USGS Publications Warehouse

    Waddle, J. Hardin; Brandt, Laura A.; Jeffery, Brian M.; Mazzotti, Frank J.

    2015-01-01

    The Everglades has been greatly reduced and is threatened by land use change and altered hydrology. The Comprehensive Everglades Restoration Plan calls for monitoring and assessment of key ecosystem attributes, one of which is abundance of American alligators. We examined 10 years of alligator night spotlight counts from Arthur R. Marshall Loxahatchee National Wildlife Refuge along two canals and in the interior marsh to determine trends and how dry years affect alligator abundance. Alligators showed population response to hydrologic conditions. In particular, there were declines in abundance after dry years followed by an apparent recovery in abundance in subsequent years. Increases in abundance were lower in the marsh than L-40 Canal. In addition, there was evidence that intensity of dry events affected population dynamics with greater declines observed in years with drier conditions. Results revealed that overall population of alligators increased from 2004 to 2013, but that increases varied by survey route. These results demonstrate that dry years cause a decline in alligator abundance proportional to the intensity of the dry event, and that it is important to make a distinction between canals and marsh when measuring alligator response to hydrology.

  19. Comparison of metabolic substrates in alligators and several birds of prey.

    PubMed

    Sweazea, Karen L; McMurtry, John P; Elsey, Ruth M; Redig, Patrick; Braun, Eldon J

    2014-08-01

    On average, avian blood glucose concentrations are 1.5-2 times those of mammals of similar mass and high concentrations of insulin are required to lower blood glucose. Whereas considerable data exist for granivorous species, few data are available for plasma metabolic substrate and glucoregulatory hormone concentrations for carnivorous birds and alligators. Birds and mammals with carnivorous diets have higher metabolic rates than animals consuming diets with less protein whereas alligators have low metabolic rates. Therefore, the present study was designed to compare substrate and glucoregulatory hormone concentrations in several birds of prey and a phylogenetically close relative of birds, the alligator. The hypothesis was that the combination of carnivorous diets and high metabolic rates favored the evolution of greater protein and fatty acid utilization leading to insulin resistance and high plasma glucose concentrations in carnivorous birds. In contrast, it was hypothesized that alligators would have low substrate utilization attributable to a low metabolic rate. Fasting plasma substrate and glucoregulatory hormone concentrations were compared for bald eagles (Haliaeetus leucocephalus), great horned owls (Bubo virginianus), red-tailed hawks (Buteo jamaicensis), and American alligators (Alligator mississippiensis). Avian species had high circulating β-hydroxybutyrate (10-21 mg/dl) compared to alligators (2.81 ± 0.16 mg/dl). In mammals high concentrations of this byproduct of fatty acid utilization are correlated with insulin resistance. Fasting glucose and insulin concentrations were positively correlated in eagles whereas no relationship was found between these variables for owls, hawks or alligators. Additionally, β-hydroxybutyrate concentrations were low in alligators. Similar to carnivorous mammals, ingestion of a high protein diet may have favored the utilization of fatty acids and protein for energy thereby promoting the development of insulin

  20. Possible generational effects of habitat degradation on alligator reproduction

    USGS Publications Warehouse

    Fujisaki, Ikuko; Rice, K.G.; Woodward, A.R.; Percival, H.F.

    2007-01-01

    Population decline of the American alligator (Alligator mississippiensis) was observed in Lake Apopka in central Florida, USA, in the early 1980s. This decline was thought to result from adult mortality and nest failure caused by anthropogenic increases in sediment loads, nutrients, and contaminants. Reproductive impairment also was reported. Extensive restoration of marshes associated with Lake Apopka has been conducted, as well as some limited restoration measures on the lake. Monitoring by the Florida Fish and Wildlife Conservation Commission (FFWCC) has indicated that the adult alligator population began increasing in the early 1990s. We expected that the previously reported high proportion of complete nest failure (??0) during the 1980s may have decreased. We collected clutches from alligator nests in Lake Apopka from 1983 to 2003 and from 5 reference areas from 1988 to 1991, and we artificially incubated them. We used a Bayesian framework with Gibbs sampler of Markov chain Monte Carlo simulation to analyze ??0. Estimated ??0was consistently higher in Lake Apopka compared with reference areas, and the difference in ??0 ranged from 0.19 to 0.56. We conducted change point analysis to identify and test the significance of the change point in ??0in Lake Apopka between 1983 and 2003, indicating the point of reproductive recovery. The estimated Bayes factor strongly supported the single change point hypothesis against the no change point hypothesis. The major downward shift in ??0 probably occurred in the mid-1990s, approximately a generation after the major population decline in the 1980s. Furthermore, estimated ??0 values after the change point (0.21) were comparable with those of reference areas (0.07-0.31). These results combined with the monitoring by FFWCC seem to suggest that anthropogenic habitat degradation caused reproductive impairment of adult females and decreases in ??0 occurred with the sexual maturity of a new generation of breeding females. Long

  1. Chronic hypoxic incubation blunts thermally dependent cholinergic tone on the cardiovascular system in embryonic American alligator (Alligator mississippiensis).

    PubMed

    Marks, Chris; Eme, John; Elsey, Ruth M; Crossley, Dane A

    2013-10-01

    Environmental conditions play a major role in shaping reptilian embryonic development, but studies addressing the impact of interactions between chronic and acute environmental stressors on embryonic systems are lacking. In the present study, we investigated thermal dependence of cholinergic and adrenergic cardiovascular tone in embryonic American alligators (Alligator mississippiensis) and assessed possible phenotypic plasticity in a chronic hypoxic incubation treatment. We compared changes in heart rate (f H) and mean arterial blood pressure (P M) for chronically hypoxic and normoxic-incubated embryos after cholinergic and adrenergic blockade following three different acute temperature treatments: (1) 30 °C (control incubation temperature), (2) acute, progressive decrease 30-24 °C then held at 24 °C, and (3) acute, progressive increase 30-36 °C then held at 36 °C. f H progressively fell in response to decreasing temperature and rose in response to increasing temperature. P M did not significantly change with decreasing temperature, but was lowered significantly with increasing acute temperature in the normoxic group at 90 % of development only. Propranolol administration (β adrenergic antagonist) produced a significant f H decrease at 24, 30, and 36 °C that was similar at all temperatures for all groups. For normoxic-incubated embryos at 90 % of development, atropine administration (cholinergic antagonist) significantly increased f H in both 24 and 36 °C treatments, but not in the 30 °C control treatment. This atropine response at 24 and 36 °C demonstrated acute thermally dependent cholinergic tone on f H late in development for normoxic-incubated, but not chronically hypoxic-incubated embryos. Collectively, data indicated that cardiovascular control mechanisms in embryonic alligators may be activated by thermal extremes, and the maturation of control mechanisms was delayed by chronic hypoxia.

  2. Fine structure of the developing epidermis in the embryo of the American alligator (Alligator mississippiensis, Crocodilia, Reptilia)

    PubMed Central

    ALIBARDI, LORENZO; THOMPSON, MICHAEL B.

    2001-01-01

    The morphological transition from the simple epidermis that contacts the amniotic fluid of embryonic crocodilians to the adult epidermis required in a terrestrial environment has never been described. We used light and electron microscopy to study the development, differentiation and keratinisation of the epidermis of the American alligator, Alligator mississippiensis, between early and late stages of embryonic skin formation. In early embryonic development, the epidermis consists of a flat bilayer. As it develops, the bilayered epidermis comes to lie beneath the peridermis. Glycogen is almost absent from the bilayered epidermis but increases in basal and suprabasal cells when scales form. Glycogen disappears from suprabasal cells that accumulate keratin. The peridermis and 1 or 2 subperidermal layers form an embryonic epidermis that is partially or totally lost before hatching. These cells accumulate coarse filaments and form reticulate bodies. Mucous and lamellate granules are produced in the Golgi apparatus and are partly secreted extracellularly. The embryonic cells darken with the formation of larger reticulate bodies that aggregate with intermediate filaments and other cell organelles, as their nuclear chromatin condenses. Thin β-cells resembling those of scutate scales of birds develop beneath the embryonic epidermis and form a stratified β-layer that varies in thickness in different body regions. The epidermis differentiates first in the back, tail and belly. At the beginning of β-cell differentiation, the cytoplasm contains sparse bundles of α-keratin filaments, glycogen and lipid droplets or vacuoles apparently derived from the endoplasmic reticulum and Golgi apparatus. These organelles disappear rapidly as irregular bundles of electron-dense β-keratin filaments accumulate and form larger bundles. The larger bundles consist of 3 nm thick electron-pale keratin microfibrils and are derived from the assemblage of β-keratin molecules produced by

  3. Specialized stem cell niche enables repetitive renewal of alligator teeth.

    PubMed

    Wu, Ping; Wu, Xiaoshan; Jiang, Ting-Xin; Elsey, Ruth M; Temple, Bradley L; Divers, Stephen J; Glenn, Travis C; Yuan, Kuo; Chen, Min-Huey; Widelitz, Randall B; Chuong, Cheng-Ming

    2013-05-28

    Reptiles and fish have robust regenerative powers for tooth renewal. However, extant mammals can either renew their teeth one time (diphyodont dentition) or not at all (monophyodont dentition). Humans replace their milk teeth with permanent teeth and then lose their ability for tooth renewal. Here, we study tooth renewal in a crocodilian model, the American alligator, which has well-organized teeth similar to mammals but can still undergo life-long renewal. Each alligator tooth is a complex family unit composed of the functional tooth, successional tooth, and dental lamina. Using multiple mitotic labeling, we map putative stem cells to the distal enlarged bulge of the dental lamina that contains quiescent odontogenic progenitors that can be activated during physiological exfoliation or artificial extraction. Tooth cycle initiation correlates with β-catenin activation and soluble frizzled-related protein 1 disappearance in the bulge. The dermal niche adjacent to the dermal lamina dynamically expresses neural cell adhesion molecule, tenascin-C, and other molecules. Furthermore, in development, asymmetric β-catenin localization leads to the formation of a heterochronous and complex tooth family unit configuration. Understanding how these signaling molecules interact in tooth development in this model may help us to learn how to stimulate growth of adult teeth in mammals.

  4. A Chinese alligator in heliox: formant frequencies in a crocodilian.

    PubMed

    Reber, Stephan A; Nishimura, Takeshi; Janisch, Judith; Robertson, Mark; Fitch, W Tecumseh

    2015-08-01

    Crocodilians are among the most vocal non-avian reptiles. Adults of both sexes produce loud vocalizations known as 'bellows' year round, with the highest rate during the mating season. Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behaviour in crocodilians. In mammals and birds, a common mechanism for producing honest acoustic signals of body size is via formant frequencies (vocal tract resonances). To our knowledge, formants have to date never been documented in any non-avian reptile, and formants do not seem to play a role in the vocalizations of anurans. We tested for formants in crocodilian vocalizations by using playbacks to induce a female Chinese alligator (Alligator sinensis) to bellow in an airtight chamber. During vocalizations, the animal inhaled either normal air or a helium/oxygen mixture (heliox) in which the velocity of sound is increased. Although heliox allows normal respiration, it alters the formant distribution of the sound spectrum. An acoustic analysis of the calls showed that the source signal components remained constant under both conditions, but an upward shift of high-energy frequency bands was observed in heliox. We conclude that these frequency bands represent formants. We suggest that crocodilian vocalizations could thus provide an acoustic indication of body size via formants. Because birds and crocodilians share a common ancestor with all dinosaurs, a better understanding of their vocal production systems may also provide insight into the communication of extinct Archosaurians.

  5. Interaction between temperature and hypoxia in the alligator.

    PubMed

    Branco, L G; Pörtner, H O; Wood, S C

    1993-12-01

    Hypoxia elicits behavioral hypothermia in alligators. Under normoxic conditions, the selected body temperature is 27.8 +/- 1.2 degrees C. However, when inspired O2 is lowered to 4%, selected body temperature decreases to 15.4 +/- 1.0 degrees C. The threshold for the behavioral hypothermia is between 4 and 5% inspired O2, the lowest threshold measured so far in terrestrial vertebrates. This study assessed the physiological significance of the behavioral hypothermia. The body temperature was clamped at 15, 25, and 35 degrees C for measurements of ventilation, blood gases, metabolic rate, plasma lactate, and acid-base status. Hypoxia-induced changes in ventilation, acid-base status, oxygen consumption, and lactate were proportional to body temperature, being pronounced at 35 degrees C, less at 25 degrees C, and absent at 15 degrees C. The correlation between selected body temperature under severe hypoxia and the measured parameters show that behavioral hypothermia is a beneficial response to hypoxia in alligators.

  6. Pulmonary gas exchange during intermittent ventilation in the American alligator.

    PubMed

    Hicks, J W; White, F N

    1992-01-01

    The present study characterized pulmonary gas exchange in the American alligator, Alligator mississipiensis during ventilation and apnea at a body temperature (Tb) of 25 degrees C. Pulmonary gas exchange parameters were measured on a breath-by-breath basis utilizing a computer-assisted data acquisition system. In addition, paired blood samples were analyzed from left and right atrium during ventilation and voluntary apneas (1, 2, 5 and 10 min). Measurements of lung PO2 and PCO2 indicated that as apnea progressed, CO2 flux into the lung decreased rapidly while O2 was continuously removed at a constant and steady rate. The reduction in VCO2 resulted in a decrease in R (less than 0.4). Blood gas measurements indicated that the pulmonary arterial-pulmonary venous PCO2 difference, (Ppa-Ppv)CO2 was 4.9 +/- 0.9 mmHg during ventilation, decreased and became negative within 2 min of apnea, reaching -3.9 +/- 0.6 mmHg after 10 min. It is postulated that during apnea the Haldane effect accounts for both the blood gas behavior across the lung and insures a continued CO2 flux into the lung during apnea.

  7. Detection of Interaural Time Differences in the Alligator

    PubMed Central

    Carr, Catherine E.; Soares, Daphne; Smolders, Jean; Simon, Jonathan Z.

    2011-01-01

    The auditory systems of birds and mammals use timing information from each ear to detect interaural time difference (ITD). To determine whether the Jeffress-type algorithms that underlie sensitivity to ITD in birds are an evolutionarily stable strategy, we recorded from the auditory nuclei of crocodilians, who are the sister group to the birds. In alligators, precisely timed spikes in the first-order nucleus magnocellularis (NM) encode the timing of sounds, and NM neurons project to neurons in the nucleus laminaris (NL) that detect interaural time differences. In vivo recordings from NL neurons show that the arrival time of phase-locked spikes differs between the ipsilateral and contralateral inputs. When this disparity is nullified by their best ITD, the neurons respond maximally. Thus NL neurons act as coincidence detectors. A biologically detailed model of NL with alligator parameters discriminated ITDs up to 1 kHz. The range of best ITDs represented in NL was much larger than in birds, however, and extended from 0 to 1000 μs contralateral, with a median ITD of 450 μs. Thus, crocodilians and birds employ similar algorithms for ITD detection, although crocodilians have larger heads. PMID:19553438

  8. Seasonal variation in plasma thyroid hormone concentrations in coastal versus inland populations of juvenile American alligators (Alligator mississippiensis): influence of plasma iodide concentrations.

    PubMed

    Boggs, Ashley S P; Hamlin, Heather J; Lowers, Russell H; Guillette, Louis J

    2011-12-01

    Thyroid hormones, essential for normal growth and health, are associated with changes in temperature, photoperiod, and reproduction. Iodide, a necessary element for thyroid hormone production, varies in diet, and is more abundant in estuarine environments, which could alter thyroid hormone variation. However, associations between thyroid hormone concentrations in animals from marine versus freshwater environments, which could become more pertinent with rising sea levels associated with global climate change, are not well studied. To determine the importance of dietary iodide in seasonal variation of plasma thyroid hormone concentrations, we analyzed seasonal variation of plasma thyroxine (T(4)) and triiodothyronine (T(3)) concentrations in juvenile alligators from an estuarine habitat (Merritt Island National Wildlife Refuge; MI) and a freshwater habitat (Lake Woodruff National Wildlife Refuge; LW) and compared these results to plasma inorganic iodide (PII) concentrations. Alligators from MI did not display seasonal variation in plasma T(4), but exhibited a seasonal pattern in plasma T(3) concentrations similar to alligators from LW. Plasma thyroid hormone concentrations were consistently higher at MI than at LW. PII concentrations were correlated with plasma T(4) and T(3) concentrations in juvenile alligators from LW but not MI. The data on plasma T(4) and T(3) concentrations suggest altered iodide metabolism in estuarine alligators. Differences in thyroid hormone concentrations between the populations could be due to differences in dietary iodide, which need to be further evaluated. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. ALTERED HISTOLOGY OF THE THYMUS AND SPLEEN IN CONTAMINANT-EXPOSED JUVENILE AMERICAN ALLIGATORS

    EPA Science Inventory

    Morphological difference in spleen and thymus are closely related to functional immune differences. Hormonal regulation of the immune system has been demonstrated in reptilian splenic and thymic tissue. Spleens and thymus were obtained from juvenile alligators at two reference si...

  10. ALTERED HISTOLOGY OF THE THYMUS AND SPLEEN IN CONTAMINANT-EXPOSED JUVENILE AMERICAN ALLIGATORS

    EPA Science Inventory

    Morphological difference in spleen and thymus are closely related to functional immune differences. Hormonal regulation of the immune system has been demonstrated in reptilian splenic and thymic tissue. Spleens and thymus were obtained from juvenile alligators at two reference si...

  11. Concentrations of contaminants in muscle of the American alligator in Florida

    SciTech Connect

    Delany, M.F.; Bell, J.U.; Sundlof, S.F.

    1988-01-01

    Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.

  12. A 3D Interactive Model and Atlas of the Jaw Musculature of Alligator mississippiensis

    PubMed Central

    Holliday, Casey M.; Tsai, Henry P.; Skiljan, Rebecca J.; George, Ian D.; Pathan, Sami

    2013-01-01

    Modern imaging and dissemination methods enable morphologists to share complex, three-dimensional (3D) data in ways not previously possible. Here we present a 3D interactive model of the jaw musculature of the American Alligator (Alligator mississippiensis). Alligator and crocodylian jaw musculature is notoriously challenging to inspect and interpret because of the derived nature of the feeding apparatus. Using Iodine-contrast enhanced microCT imaging, a segmented model of jaw muscles, trigeminal nerve, brain and skull are presented as a cross-sectional atlas and 3D, interactive pdf of the rendered model. Modern 3D dissemination methods like this 3D Alligator hold great potential for morphologists to share anatomical information to scientists, educators, and the public in an easily downloadable format. PMID:23762228

  13. A 3D interactive model and atlas of the jaw musculature of Alligator mississippiensis.

    PubMed

    Holliday, Casey M; Tsai, Henry P; Skiljan, Rebecca J; George, Ian D; Pathan, Sami

    2013-01-01

    Modern imaging and dissemination methods enable morphologists to share complex, three-dimensional (3D) data in ways not previously possible. Here we present a 3D interactive model of the jaw musculature of the American Alligator (Alligator mississippiensis). Alligator and crocodylian jaw musculature is notoriously challenging to inspect and interpret because of the derived nature of the feeding apparatus. Using Iodine-contrast enhanced microCT imaging, a segmented model of jaw muscles, trigeminal nerve, brain and skull are presented as a cross-sectional atlas and 3D, interactive pdf of the rendered model. Modern 3D dissemination methods like this 3D Alligator hold great potential for morphologists to share anatomical information to scientists, educators, and the public in an easily downloadable format.

  14. Concentrations of contaminants in muscle of the American alligator in Florida

    SciTech Connect

    Delany, M.F.; Bell, J.U.; Sundlof, S.F.

    1988-01-01

    Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.

  15. Altered histology of the thymus and spleen in contaminant-exposed juvenile American alligators.

    PubMed

    Rooney, Andrew A; Bermudez, Dieldrich S; Guillette, Louis J

    2003-06-01

    Morphological differences in spleen and thymus are closely related to functional immune differences. Hormonal regulation of the immune system has been demonstrated in reptilian splenic and thymic tissue. Spleens and thymus were obtained from juvenile alligators at two reference sites in Florida, USA: Orange Lake and a National Wildlife Refuge, Lake Woodruff, as well as from a contaminated lake, Lake Apopka. Lake Apopka has been extensively polluted with agricultural pesticides. Tissues were prepared for histological analysis to determine if previously detected endocrine abnormalities associated with contaminant exposure might also be reflected in morphological differences in splenic and thymic structures important for immunological response. Similar tissues were taken from captive-raised juvenile female alligators (3 years old) that were hatched from eggs collected on Lake Woodruff and Lake Apopka. Differences in thymic ratios (medulla/cortex) were found among alligators collected from the two lakes (P = 0.0051). Alligators from Lake Apopka had smaller thymic ratios than animals from either reference lake. Males from Lake Woodruff had significantly smaller lymphocyte sheaths in the spleen than females (P = 0.0009), indicative of a normal sexual dimorphism. Lymphocyte sheath width differed among females obtained from the three lakes, with females from Lake Apopka having the smallest sheath width and those from Orange Lake having the largest. Malpighian body area was largest in alligators from Orange Lake, intermediate in Lake Woodruff, and smallest in Lake Apopka. In contrast to that observed for wild-caught animals, no difference was found in the thymic medulla/cortex ratio of captive-raised female alligators (P = 0.378). Captive-raised female alligators from Lake Apopka and Lake Woodruff displayed lake-associated differences in lymphocyte sheath width as observed in wild animals; Lake Apopka alligators had smaller lymphocyte sheath width compared to Woodruff

  16. WILDLIFE - ALLIGATOR STRADDLES TWO PARKING SPACES IN FRONT OF OFFICE TRAILER

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Double-parked, an angry alligator straddles two parking spaces outside an office trailer at NASA's Launch Complex 17. Hank Curtin of Pan Am watches from a safe perch as John Tanner gets ready to wrap a rope around the snout of the 10-foot, 9-inch beast. It's all in a day's work for Tanner, who has a contract with the state of Florida to remove nuisance alligators.

  17. Scale-dependent habitat selection and size-based dominance in adult male American alligators

    USGS Publications Warehouse

    Strickland, Bradley A.; Vilella, Francisco; Belant, Jerrold L.

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  18. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators.

    PubMed

    Strickland, Bradley A; Vilella, Francisco J; Belant, Jerrold L

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  19. Maternal investment and nutrient use affect phenotype of American alligator and domestic chicken hatchlings.

    PubMed

    Nelson, Thomas C; Groth, Kevin D; Sotherland, Paul R

    2010-09-01

    Maternal investment by oviparous amniotes, in the form of yolk and albumen, and the mechanisms by which embryos use available energy and nutrients have a profound effect on embryo and, consequently, hatchling phenotype. Nutrient provisioning and uptake vary within and among oviparous taxa, avian and non-avian reptiles, due to differences and similarities in environment, behavior, and phylogeny. Eggs of crocodilians, the closest extant relatives to modern birds, are ideal models for examining modes of embryonic development, especially with regard to nutrient uptake, in non-avian reptiles and comparing them with those of birds. In this study, we investigated egg composition, embryo growth, and nutrient use in the domestic chicken (Gallus gallus) and American alligator (Alligator mississippiensis). We explored egg composition by separating and weighing components of fresh eggs. We measured embryo growth and nutrient usage by dissecting embryos and by obtaining samples of liquid from the amnion, digestive tract, and yolk sac throughout the last half of incubation. Variation in albumen mass contributed most to egg mass variation in chicken eggs, whereas alligator eggs were composed almost equally of yolk and albumen, although larger eggs contained proportionally more albumen and less yolk than smaller eggs. Both chicken and alligator albumen were mostly water (87% and 96%, respectively) although chicken albumen contained over three times more solid mass per gram than alligator albumen. In both species, yolk contained a high proportion of solids. Larger eggs produced larger hatchlings in both chickens and alligators, but albumen solids contributed to embryo mass only in chicken embryos. However, intact albumen proteins appeared in the stomach in embryos of both species. While the final disposition of albumen in alligators is unclear, variation in maternal investment of yolk at oviposition was responsible for nearly all of the variation in alligator hatchling phenotype

  20. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators

    PubMed Central

    Strickland, Bradley A.; Vilella, Francisco J.; Belant, Jerrold L.

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  1. WILDLIFE - ALLIGATOR STRADDLES TWO PARKING SPACES IN FRONT OF OFFICE TRAILER

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Double-parked, an angry alligator straddles two parking spaces outside an office trailer at NASA's Launch Complex 17. Hank Curtin of Pan Am watches from a safe perch as John Tanner gets ready to wrap a rope around the snout of the 10-foot, 9-inch beast. It's all in a day's work for Tanner, who has a contract with the state of Florida to remove nuisance alligators.

  2. Does variation in movement tactics and trophic interactions among American alligators create habitat linkages?

    PubMed

    Rosenblatt, Adam E; Heithaus, Michael R

    2011-07-01

    1. Highly mobile top predators are hypothesized to spatially and/or temporally link disparate habitats through the combination of their movement and feeding patterns, but recent studies suggest that individual specialization in habitat use and feeding could keep habitats compartmentalized. 2. We used passive acoustic telemetry and stable isotope analysis to investigate whether specialization in movement and feeding patterns of American alligators (Alligator mississippiensis) in an oligotrophic subtropical estuary created habitat linkages between marine and estuarine/freshwater food webs. 3. Individual alligators adopted one of the three relatively distinct movement tactics that were linked to variation in diets. Fifty-six per cent of alligators regularly travelled from the upstream (freshwater/mid-estuary) areas into the downstream (marine-influenced) areas where salinities exceed those typically tolerated by alligators. Thirty-one per cent of the alligators made regular trips from the mid-estuarine habitat into the upstream habitat; 13% remained in the mid-estuary zone year-round. 4. Stable isotopic analysis indicated that, unlike individuals remaining in the mid-estuary and upstream zones, alligators that used the downstream zone fed at least partially from marine food webs and likely moved to access higher prey abundance at the expense of salt stress. Therefore, 'commuting' alligators may link marine food webs with those of the estuary and marshes in the coastal Everglades and create an upstream vector for allochthonous nutrient inputs into the estuary. 5. This study lends further support to the hypothesis that large-bodied highly mobile predators faced with trade-offs are likely to exhibit individual specialization leading to habitat linkages, rather than compartmentalization. However, the conditions under which this scenario occurs require further investigation. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

  3. The reproductive hormone cycle of adult female American alligators from a barrier island population.

    PubMed

    Hamlin, Heather J; Lowers, Russell H; Kohno, Satomi; Mitsui-Watanabe, Naoko; Amano, Haruna; Hara, Akihiko; Ohta, Yasuhiko; Miyagawa, Shinichi; Iguchi, Taisen; Guillette, Louis J

    2014-06-01

    Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17β-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.

  4. Seasonal variation in plasma sex steroid concentrations in juvenile American alligators.

    PubMed

    Rooney, Andrew A; Crain, D Andrew; Woodward, Allan R; Guillette, Louis J

    2004-01-01

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make a limited comparison of these seasonal patterns on two different lakes in Florida. Male juvenile alligators from a reference lake, Lake Woodruff, displayed temporal patterns in plasma testosterone (T) concentrations that appear to be seasonal. A similar pattern in plasma estradiol-17beta (E(2)) was observed in juvenile females from Lake Woodruff. Males had significantly elevated T concentrations during the spring and late summer, whereas females had elevated E(2) in the spring and late summer and significantly depressed E(2) concentrations during the winter. A limited 4-month survey of animals from contaminated Lake Apopka found a lack of such seasonality. These results suggest that: (1) healthy wild populations of juvenile alligators have a prolonged peripubescent period that is marked by seasonal hormonal cycles, (2) juvenile alligators exposed to environmental contaminants can lack such seasonal cyclicity, and (3) future studies of juvenile alligators should incorporate such seasonality into the experimental design.

  5. The tale of the tail: limb function and locomotor mechanics in Alligator mississippiensis.

    PubMed

    Willey, Jeffrey S; Biknevicius, Audrone R; Reilly, Stephen M; Earls, Kathleen D

    2004-01-01

    Crocodilians tow their large muscular tail behind them during terrestrial bouts when they high walk (a walking trot). Analysis of ground reaction forces in the American alligator (Alligator mississippiensis) revealed the consequences of tail-dragging. Individual limb and tail ground reaction force records show that the hindlimbs of Alligator take on a substantial role in body mass support consistent with the more caudal location of its center of mass due to the presence of a particularly heavy tail (representing nearly 28% of total body mass). Furthermore, because the constant drag imposed by the tail is substantial, both fore- and hindlimbs in Alligator have a heightened propulsive role as a means of countering the net braking effect of the tail. Ground reaction forces of the whole body were used to assess how well Alligator was able to utilize mechanical energy-saving mechanisms (inverse pendulum or mass-spring). A high-walking Alligator recovers, on average, about 20% of its mechanical energy by inverse pendulum mechanics. These modest energy recovery levels are likely to be due to a combination of factors that may include low locomotor speed, imprecise coordination of contralateral limbs in the trot, frequent dragging of feet of protracting limbs during swing phase and, possibly, tail dragging.

  6. Relationship between body condition of American alligators and water depth in the Everglades, Florida

    USGS Publications Warehouse

    Fujisaki, Ikuko; Rice, Kenneth G.; Pearlstine, Leonard G.; Mazzotti, Frank J.

    2009-01-01

    Feeding opportunities of American alligators (Alligator mississippiensis) in freshwater wetlands in south Florida are closely linked to hydrologic conditions. In the Everglades, seasonally and annually fluctuating surface water levels affect populations of aquatic organisms that alligators consume. Since prey becomes more concentrated when water depth decreases, we hypothesized an inverse relationship between body condition and water depth in the Everglades. On average, condition of adult alligators in the dry season was significantly higher than in the wet season, but this was not the case for juveniles/subadults. The correlation between body condition and measured water depth at capture locations was weak; however, there was a significant negative correlation between the condition and predicted water depth prior to capture for all animals except for spring juveniles/subadults which had a weak positive condition-water depth relationship. Overall, a relatively strong inverse correlation occurred at 10-49 days prior to the capture day, suggesting that current body condition of alligators may depend on feeding opportunities during that period. Fitted regression of body condition on water depth (mean depth of 10 days when condition-water depth correlation was greatest) resulted in a significantly negative slope, except for spring adult females and spring juveniles/subadults for which slopes were not significantly different from zero. Our results imply that water management practices may be critical for alligators in the Everglades since water depth can affect animal condition in a relatively short period of time.

  7. Detection of West Nile virus RNA in mosquitoes and identification of mosquito blood meals collected at alligator farms in Louisiana.

    PubMed

    Unlu, Isik; Kramer, Wayne L; Roy, Alma F; Foil, Lane D

    2010-07-01

    Since 2001, alligator farms in the United States have sustained substantial economic losses because of West Nile virus (WNV) outbreaks in American alligators (Alligator mississippiensis). Once an initial infection is introduced into captive alligators, WNV can spread among animals by contaminative transmission. Some outbreaks have been linked to feeding on infected meat or the introduction of infected hatchlings, but the initial source of WNV infection has been uncertain in other outbreaks. We conducted a study to identify species composition and presence of WNV in mosquito populations associated with alligator farms in Louisiana. A second objective of this study was to identify the origin of mosquito blood meals collected at commercial alligator farms. Mosquitoes were collected from 2004 to 2006, using Centers for Disease Control light traps, gravid traps, backpack aspirators, and resting boxes. We collected a total of 58,975 mosquitoes representing 24 species. WNV was detected in 41 pools of females from 11 mosquito species: Anopheles crucians, Anopheles quadrimaculatus, Coquillettidia perturbans, Culex coronator, Culex erraticus, Culex nigripalpus, Culex quinquefasciatus, Mansonia titillans, Aedes sollicitans, Psorophora columbiae, and Uranotaenia lowii. The blood meal origins of 213 field-collected mosquitoes were identified based on cytochrome B sequence identity. Alligator blood was detected in 21 mosquitoes representing six species of mosquitoes, including Cx. quinquefasciatus and Cx. nigripalpus. Our results showed that mosquitoes of species that are known to be competent vectors of WNV fed regularly on captive alligators. Therefore, mosquitoes probably are important in the role of transmission of WNV at alligator farms.

  8. Use of alligator hole abundance and occupancy rate as indicators for restoration of a human-altered wetland

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, Frank J.; Hart, Kristen M.; Rice, Kenneth G.; Ogurcak, Danielle; Rochford, Michael; Jeffery, Brian M.; Brandt, Laura A.; Cherkiss, Michael S.

    2012-01-01

    Use of indicator species as a measure of ecosystem conditions is an established science application in environmental management. Because of its role in shaping wetland systems, the American alligator (Alligator mississippiensis) is one of the ecological indicators for wetland restoration in south Florida, USA. We conducted landscape-level aerial surveys of alligator holes in two different habitats in a wetland where anthropogenic modification of surface hydrology has altered the natural system. Alligator holes were scarcer in an area where modified hydrology caused draining and frequent dry-downs compared to another area that maintains a functional wetland system. Lower abundance of alligator holes indicates lack of alligator activities, lower overall species diversity, and lack of dry-season aquatic refugia for other organisms. The occupancy rate of alligator holes was lower than the current restoration target for the Everglades, and was variable by size class with large size-class alligators predominantly occupying alligator holes. This may indicate unequal size-class distribution, different habitat selection by size classes, or possibly a lack of recruitment. Our study provides pre-restoration baseline information about one indicator species for the Everglades. Success of the restoration can be assessed via effective synthesis of information derived by collective research efforts on the entire suite of selected ecological indicators.

  9. TEMPORAL AND SPATIAL VARIATION IN PLASMA THYROXINE (T4) CONCENTRATIONS IN JUVENILE ALLIGATORS COLLECTED FROM LAKE OKEECHOBEE AND THE NORTHERN EVERGLADES, FLORIDA, USA

    EPA Science Inventory

    We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site...

  10. TEMPORAL AND SPATIAL VARIATION IN PLASMA THYROXINE (T4) CONCENTRATIONS IN JUVENILE ALLIGATORS COLLECTED FROM LAKE OKEECHOBEE AND THE NORTHERN EVERGLADES, FLORIDA, USA

    EPA Science Inventory

    We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site...

  11. Alligator rivers analogue project an OECD/NEA international project

    SciTech Connect

    Duerden, P.; Airey, P.; Pescatore, C.

    1994-12-31

    The Koongarra uranium deposit in the Alligator Rivers Region of the Northern Territory of Australia was studied as a natural analogue of the far field behaviour of high level waste repositories following groundwater ingress. A number of mathematical modelling approaches were developed for processes as diverse as groundwater transport, host rock weathering, radionuclide sorption, evolution of the uranium dispersion fan and the distribution of uranium series nuclides between mineral assemblages in weathered host rock. Some of these models are relevant to performance assessment at the level of individual processes and subsystem performance. Through the project, new insights into the application of the natural analogue approach to the assessment of potential waste repository sites were obtained.

  12. Isolation and characterization of sulfite oxidase from Alligator mississipiensis

    SciTech Connect

    Robbins, A.; Neame, P.J.; Barber, M.J. )

    1991-03-11

    Sulfite oxidase has been isolated from fresh alligator liver using ammonium sulfate and acetone fractionation, DEAE chromatography and FPLC on Mono Q. The enzyme is dimeric and exhibits a subunit M. Wt. of approximately 58 kDa, larger than that of chicken SO. EPR spectroscopy of the partially-reduced enzyme revealed a single Mo(V) species while visible spectroscopy revealed the presence of cytochrome b{sub 557}. Maximal activities were obtained at pH 8 and 9, respectively. K{sub m}'s for SO{sub 3}{sup 2 {minus}}, cyt. c and Fe(CN){sub 6}{sup 3 {minus}} were 23.5 uM, 2.9 uM and 8.0 uM, respectively. Sequencing of peptides obtained by endoprotease K digestion indicated regions of extensive sequence similarity to chicken and rat enzymes in both heme and Mo-pterin domains. Regions of sequence dissimilarity were also found.

  13. Biochemical composition of the alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

    NASA Astrophysics Data System (ADS)

    Sanaye, Sushant Vilas; Pawar, Ashwini Pandurang; Rivonker, Chandrasheker Umanath; Sreepada, Rayadurga Anantha; Ansari, Zakir Ali; Ram, Anirudh

    2016-12-01

    Considering the economic importance in traditional Chinese medicine (TCM) and lack of baseline information, we evaluated the proximate composition, fatty acid and amino acid profiles, trace element content and C:N ratio in the alligator pipefish, Syngnathoides biaculeatus. Amongst proximate principals, a crude protein formed the major biochemical component ((58.9±2.2)% dry weight). Mean percent concentrations (dry weight) of other components such as a total lipid (TL), ash and nitrogen-free extract measured were, (1.8±0.2)%, (19.2±2.2)% and (20.1±0.45)%, respectively. The fatty acid profile revealed the presence of 27 saturated fatty acids (SFA) with 13 straight-chained and 14 branched-chained, 28 unsaturated fatty acids (UFA) with 14 monounsaturated and 14 polyunsaturated and nine other minor fatty acids. Mean percent contributions of total SFAs and UFAs to TL were found to be (55.41±0.24)% and (44.05±0.25)%, respectively. Altogether, 16 different amino acids with an equal number of essential (EAA) and non-essential (NAA) ones were identified. Percent contributions by EAA and NAA to the total amino acid content were 38.11% and 61.89%, respectively. Trace metal concentrations in S. biaculeatus were generally low and their distribution followed the order, Mg>Fe>Zn>Mn>Cu>Cr>Ni>Hg>Co. The C:N ratio was (4.37±0.04)%. The profile of major biochemical constituents in alligator pipefish, S. biaculeatus revealed its potential use in TCM as well as a nutritional diet for human consumption. The results of the study would also form the basis for formulation and optimization of diets for the culture of S. biaculeatus.

  14. Posthatching development of Alligator mississippiensis ovary and testis.

    PubMed

    Moore, Brandon C; Hamlin, Heather J; Botteri, Nicole L; Lawler, Ashley N; Mathavan, Ketan K; Guillette, Louis J

    2010-05-01

    We investigated ovary and testis development of Alligator mississippiensis during the first 5 months posthatch. To better describe follicle assembly and seminiferous cord development, we used histochemical techniques to detect carbohydrate-rich extracellular matrix components in 1-week, 1-month, 3-month, and 5-month-old gonads. We found profound morphological changes in both ovary and testis. During this time, oogenesis progressed up to diplotene arrest and meiotic germ cells increasingly interacted with follicular cells. Concomitant with follicles becoming invested with full complements of granulosa cells, a periodic acid Schiff's (PAS)-positive basement membrane formed. As follicles enlarged and thecal layers were observed, basement membranes and thecal compartments gained periodic acid-methionine silver (PAMS)-reactive fibers. The ovarian medulla increased first PAS- and then PAMS reactivity as it fragmented into wide lacunae lined with low cuboidal to squamous epithelia. During this same period, testicular germ cells found along the tubule margins were observed progressing from spermatogonia to round spermatids located within the center of tubules. Accompanying this meiotic development, interstitial Leydig cell clusters become more visible and testicular capsules thickened. During the observed testis development, the thickening tunica albuginea and widening interstitial tissues showed increasing PAS- and PAMS reactivity. We observed putative intersex structures in both ovary and testis. On the coelomic aspect of testes were cell clusters with germ cell morphology and at the posterior end of ovaries, we observed "medullary rests" resembling immature testis cords. We hypothesize laboratory conditions accelerated gonad maturation due to optimum conditions, including nutrients and temperature. Laboratory alligators grew more rapidly and with increased body conditions compared with previous measured, field-caught animals. Additionally, we predict the morphological

  15. Post-hatching development of Alligator mississippiensis ovary and testis

    PubMed Central

    Moore, Brandon C.; Hamlin, Heather J.; Botteri, Nicole L.; Lawler, Ashley N.; Mathavan, Ketan K.; Guillette, Louis J.

    2009-01-01

    We investigated ovary and testis development of Alligator mississippiensis during the first five months post-hatch. To better describe follicle assembly and seminiferous cord development, we employed histochemical techniques to detect carbohydrate-rich extracellular matrix components in one-week, one-month, three-month, and five-month-old gonads. We found profound morphological changes in both ovary and testis. During this time, oogenesis progressed up to diplotene arrest and meiotic germ cells increasingly interacted with follicular cells. Concomitant with follicles becoming invested with full complements of granulosa cells, a periodic acid Schiff’s (PAS)-positive basement membrane formed. As follicles enlarged and thecal layers were observed, basement membranes and thecal compartments gained periodic acid-methionine silver (PAMS)-reactive fibers. The ovarian medulla increased first PAS- and then PAMS-reactivity as it fragmented into wide lacunae lined with low cuboidal to squamous epithelia. During this same period, testicular germ cells found along the tubule margins were observed progressing from spermatogonia to round spermatids located within the center of tubules. Accompanying this meiotic development, interstitial Leydig cell clusters become more visible and testicular capsules thickened. During the observed testis development, the thickening tunica albuginea and widening interstitial tissues showed increasing PAS- and PAMS-reactivity. We observed putative inter-sex structures in both ovary and testis. On the coelomic aspect of testes were cell clusters with germ cell morphology and at the posterior end of ovaries, we observed “medullary rests” resembling immature testis cords. We hypothesize laboratory conditions accelerated gonad maturation due to optimum conditions, including nutrients and temperature. Laboratory alligators grew more rapidly and with increased body conditions compared to previous measured, field-caught animals. Additionally, we

  16. A Chinese alligator in heliox: formant frequencies in a crocodilian

    PubMed Central

    Reber, Stephan A.; Nishimura, Takeshi; Janisch, Judith; Robertson, Mark; Fitch, W. Tecumseh

    2015-01-01

    ABSTRACT Crocodilians are among the most vocal non-avian reptiles. Adults of both sexes produce loud vocalizations known as ‘bellows’ year round, with the highest rate during the mating season. Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behaviour in crocodilians. In mammals and birds, a common mechanism for producing honest acoustic signals of body size is via formant frequencies (vocal tract resonances). To our knowledge, formants have to date never been documented in any non-avian reptile, and formants do not seem to play a role in the vocalizations of anurans. We tested for formants in crocodilian vocalizations by using playbacks to induce a female Chinese alligator (Alligator sinensis) to bellow in an airtight chamber. During vocalizations, the animal inhaled either normal air or a helium/oxygen mixture (heliox) in which the velocity of sound is increased. Although heliox allows normal respiration, it alters the formant distribution of the sound spectrum. An acoustic analysis of the calls showed that the source signal components remained constant under both conditions, but an upward shift of high-energy frequency bands was observed in heliox. We conclude that these frequency bands represent formants. We suggest that crocodilian vocalizations could thus provide an acoustic indication of body size via formants. Because birds and crocodilians share a common ancestor with all dinosaurs, a better understanding of their vocal production systems may also provide insight into the communication of extinct Archosaurians. PMID:26246611

  17. Thermal acclimation, mitochondrial capacities and organ metabolic profiles in a reptile (Alligator mississippiensis).

    PubMed

    Guderley, Helga; Seebacher, Frank

    2011-01-01

    Reptiles thermoregulate behaviourally, but change their preferred temperature and the optimal temperature for performance seasonally. We evaluated whether the digestive and locomotor systems of the alligator show parallel metabolic adjustments during thermal acclimation. To this end, we allowed juvenile alligators to grow under thermal conditions typical of winter and summer, providing them with seasonally appropriate basking opportunities. Although mean body temperatures of alligators in these groups differed by approximately 10°C, their growth and final anatomic status was equivalent. While hepatic mitochondria isolated from cold-acclimated alligators had higher oxidative capacities at 30°C than those from warm-acclimated alligators, the capacities did not differ at 20°C. Cold acclimation decreased maximal oxidative capacities of muscle mitochondria. For mitochondria from both organs and acclimation groups, palmitate increased oligomycin-inhibited respiration. GDP addition reduced palmitate-uncoupled rates more in liver mitochondria from warm- than cold-acclimated alligators. In muscle mitochondria, carboxyatractyloside significantly reduced palmitate-uncoupled rates. This effect was not changed by thermal acclimation. The aerobic capacity of liver, skeletal muscle and duodenum, as estimated by activities of cytochrome c oxidase (COX), increased with cold acclimation. At acclimation temperatures, the activities of COX and citrate synthase (CS) in these organs were equivalent. By measuring COX and CS in isolated mitochondria and tissue extracts, we estimated that cold acclimation did not change the mitochondrial content in liver, but increased that of muscle. The thermal compensation of growth rates and of the aerobic capacity of the locomotor and digestive systems suggests that alligators optimised metabolic processes for the seasonally altered, preferred body temperature. The precision of this compensatory response exceeds that typically shown by aquatic

  18. Free body analysis, beam mechanics, and finite element modeling of the mandible of Alligator mississippiensis.

    PubMed

    Porro, Laura B; Holliday, Casey M; Anapol, Fred; Ontiveros, Lupita C; Ontiveros, Lolita T; Ross, Callum F

    2011-08-01

    The mechanical behavior of mammalian mandibles is well-studied, but a comprehensive biomechanical analysis (incorporating detailed muscle architecture, accurate material properties, and three-dimensional mechanical behavior) of an extant archosaur mandible has never been carried out. This makes it unclear how closely models of extant and extinct archosaur mandibles reflect reality and prevents comparisons of structure-function relationships in mammalian and archosaur mandibles. We tested hypotheses regarding the mechanical behavior of the mandible of Alligator mississippiensis by analyzing reaction forces and bending, shear, and torsional stress regimes in six models of varying complexity. Models included free body analysis using basic lever arm mechanics, 2D and 3D beam models, and three high-resolution finite element models of the Alligator mandible, incorporating, respectively, isotropic bone without sutures, anisotropic bone with sutures, and anisotropic bone with sutures and contact between the mandible and the pterygoid flange. Compared with the beam models, the Alligator finite element models exhibited less spatial variability in dorsoventral bending and sagittal shear stress, as well as lower peak values for these stresses, suggesting that Alligator mandibular morphology is in part designed to reduce these stresses during biting. However, the Alligator models exhibited greater variability in the distribution of mediolateral and torsional stresses than the beam models. Incorporating anisotropic bone material properties and sutures into the model reduced dorsoventral and torsional stresses within the mandible, but led to elevated mediolateral stresses. These mediolateral stresses were mitigated by the addition of a pterygoid-mandibular contact, suggesting important contributions from, and trade-offs between, material properties and external constraints in Alligator mandible design. Our results suggest that beam modeling does not accurately represent the

  19. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... laws regulating harvest seasons and methods. (iii) Total allowable harvest of the species. (iv..., including harvest of nuisance alligators, methods used to determine harvest levels, demographics of the harvest, and methods used to determine the total number and population trends of alligators in the wild...

  20. Chronic Ingestion of Coal Fly-Ash Contaminated Prey and Its Effects on Health and Immune Parameters in Juvenile American Alligators (Alligator mississippiensis).

    PubMed

    Finger, John W; Hamilton, Matthew T; Metts, Brian S; Glenn, Travis C; Tuberville, Tracey D

    2016-10-01

    Coal-burning power plants supply approximately 37 % of the electricity in the United States. However, incomplete combustion produces ash wastes enriched with toxic trace elements that have historically been disposed of in aquatic basins. Organisms inhabiting such habitats may accumulate these trace elements; however, studies investigating the effects on biota have been primarily restricted to shorter-lived, lower-trophic organisms. The American alligator (Alligator mississippiensis), a long-lived, top-trophic carnivore, has been observed inhabiting these basins, yet the health or immune effects of chronic exposure and possible accumulation remains unknown. In this study, we investigated how chronic dietary ingestion of prey contaminated with coal combustion wastes (CCWs) for 25 months, and subsequent accumulation of trace elements present in CCWs, affected juvenile alligator immune function and health. Alligators were assigned to one of four dietary-treatment groups including controls and those fed prey contaminated with CCWs for one, two, or three times a week. However, no effect of Dietary Treatment (p > 0.05) was observed on any immune parameter or hematological or plasma analyte we tested. Our results suggest that neither exposure to nor accumulation of low doses of CCWs had a negative effect on certain aspects of the immune and hematological system. However, future studies are required to elucidate this further.

  1. Temporal profile of nerve growth factor expression in the partial central nervous system of the Yangtze alligator Alligator sinensis (Reptilia,Crocodylia) during early postnatal growth.

    PubMed

    Zheng, Lanrong; Chen, Fangfang; Wang, Renping; Zhou, Yongkang; Wu, Xiaobing

    2013-05-01

    Expression of nerve growth factor (NGF) in structures of the partial central nervous system of the Yangtze alligator, Alligator sinensis (Reptilia, Crocodylia) was examined during early postnatal growth using immunohistochemistry and Western blot assays. In animals 0-2 years of age NGF-positive cells in the cerebral cortex increased gradually in number and size, and were predominantly distributed in the molecular layer. NGF-positive cells in the midbrain showed similar increases but with predominant distribution in the ependymal layer. NGF-positive cells increased in the cerebellum between 0 and 1 years of age, with increased NGF expression being seen during the first 2 years of life mostly in the ependymal layer. NGF-positive cells were mainly found in the gray matter of the spinal cord with decreasing cell numbers, NGF expression levels being seen from 0 to 2 years and small processes without synaptic connection from 1 to 2 years. These results suggest that NGF is involved in the early postnatal growth of several structures of Yangtze alligator partial central nervous system, suggesting a possible role of NGF in the Yangtze alligator partial central nervous system.

  2. Phase I and II liver enzyme activities in juvenile alligators (Alligator mississippiensis) collected from three sites in the Kissimmee-Everglades drainage, Florida (USA).

    PubMed

    Gunderson, M P; Oberdörster, E; Guillette, L J

    2004-10-01

    We examined CYP1A (measured using hepatic EROD and MROD activities) and glutathione-S-transferase (GST) activities in juvenile alligators (Alligator mississippiensis) collected from three sites with varying contamination in the Kissimmee-Everglades drainage in south Florida. We hypothesized that contaminants present in areas with intermediate or higher contaminant concentrations would alter hepatic enzyme activities in juvenile alligators from those sites when compared to hepatic enzyme activity in animals from the area with the least contamination. EROD activity was found to be higher in animals from the site with lower reported levels of contamination relative to those from the site with the highest reported contamination suggesting an inhibition of CYP1A expression or activity. No differences among animals from the three sites were observed for hepatic MROD and GST activities. A significant negative relationship between EROD, MROD, and GST activities and body size was exhibited in alligators from the site with the lowest contamination. No relationship between body size and hepatic enzyme activity was found in animals from the sites with intermediate and higher contamination, suggesting that contaminants present at these sites act to alter this relationship. No correlation was observed in this study between plasma steroid concentrations (estradiol-17 beta or testosterone) and hepatic EROD, MROD, or GST activities.

  3. The influence of regional hydrology on nesting behavior and nest fate of the American alligator

    USGS Publications Warehouse

    Ugarte, Cristina A.; Bass, Oron L.; Nuttle, William; Mazzotti, Frank J.; Rice, Kenneth G.; Fujisaki, Ikuko; Whelan, Kevin R.T.

    2013-01-01

    Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species.

  4. Morphology of the embryonic and hatchling American alligator ductus arteriosi and implications for embryonic cardiovascular shunting.

    PubMed

    Jacobs, Kimberley; Goy, Sarah K; Dzialowski, Edward M

    2012-02-01

    The ductus arteriosi (DA) are embryonic blood vessels found in amniotic vertebrates that shunt blood away from the pulmonary artery and lungs and toward the aorta. Here, we examine changes in morphology of the right and left DA (LDA), and right and left aorta (LAo) from embryonic and hatchling alligators. The developing alligator has two-patent DA that join the right and LAo. Both DA exhibit a muscular phenotype composed of an internal smooth muscle layer (2-4 cells thick). At hatching, the lumen diameter of both DA decreases as the vessels begin to close within the first 12 h of posthatch life. Between day 1 and day 12 posthatching, the vessel becomes fully occluded with endothelial and smooth muscle cells filling the lumen. A number of DA from hatchlings contained blood clots along their length. The lumen of the full term alligator DA is reduced in comparison with the full term chicken DA. The developing alligator embryo has an additional right-to-left shunt pathway in the LAo arising from the right ventricle. The embryonic LAo diameter is twice the diameter of either the right DA or LDA, providing a lower resistance pathway for blood leaving the right ventricle. On the basis of these findings, we propose that the paired DA of the embryonic alligator have a reduced role in the embryonic right-to-left shunt of blood from the right ventricle when compared with the avian DA.

  5. The effects of hurricane Rita and subsequent drought on alligators in southwest Louisiana.

    PubMed

    Lance, Valentine A; Elsey, Ruth M; Butterstein, George; Trosclair, Phillip L; Merchant, Mark

    2010-02-01

    Hurricane Rita struck the coast of southwest Louisiana in September 2005. The storm generated an enormous tidal surge of approximately four meters in height that inundated many thousands of acres of the coastal marsh with full strength seawater. The initial surge resulted in the deaths of a number of alligators and severely stressed those who survived. In addition, a prolonged drought (the lowest rainfall in 111 years of recorded weather data) following the hurricane resulted in highly saline conditions that persisted in the marsh for several months. We had the opportunity to collect 11 blood samples from alligators located on Holly Beach less than a month after the hurricane, but were unable to collect samples from alligators on Rockefeller Wildlife Refuge until February 2006. Conditions at Rockefeller Refuge did not permit systematic sampling, but a total of 201 samples were collected on the refuge up through August 2006. The blood samples were analyzed for sodium, potassium, chloride, osmolality, and corticosterone. Blood samples from alligators sampled on Holly Beach in October 2005, showed a marked elevation in plasma osmolality, sodium, chloride, potassium, corticosterone, and an elevated heterophil/lymphocyte ratio. Blood samples from alligators on Rockefeller Refuge showed increasing levels of corticosterone as the drought persisted and elevated osmolality and electrolytes. After substantial rainfall in July and August, these indices of osmotic stress returned to within normal limits. (c) 2009 Wiley-Liss, Inc.

  6. Body temperatures and behavior of American alligators during cold winter weather

    SciTech Connect

    Brisbin, I.L., Jr.; Standora, E.A.; Vargo, M.J.

    1982-04-01

    Data from two large (188 and 135 kg) male alligators (Alligator mississippiensis) indicated that 4-5 C seemed to be the lowest body temperatures that they could endure with subsequent recovery. Although one animal in shallow water managed to keep a breathing hole open for several days, in ice that was 1.5 cm thick, it later died following a decrease of its body temperature to 4.0 C. The second alligator which was located in a deeper portion of the reservoir used both terrestrial and aquatic basking behavior to raise its body temperature and level of activity. Except in the case of basking events, there was not clear evidence of significant evaluations of the body temperatures of either the live or dead alligators above those of their adjacent water. When located side-by-side, diurnal cycles of deep body temperatures exceeding adjacent water temperatures to a maximum extent near dawn and usually falling below water temperatures during the afternoon and early evening hours. The physical properties and thermal inertia of the bodies of such large alligators, when placed in appropriate microclimates, may be sufficient in themselves to explain the general patterns and levels of body temperature changes observed at these low temperatures.

  7. Effects of egg and hatchling harvest on American alligators in Florida

    USGS Publications Warehouse

    Rice, K.G.; Percival, H.F.; Woodward, A.R.; Jennings, Michael L.

    1999-01-01

    Harvest of crocodilian eggs and young for captive rearing (ranching) has been used worldwide as an option for producing crocodilian skins and meat from wild stock. The long-term effects of harvesting a certain proportion of early age class, wild American alligators (Alligator mississippiensis) without repatriation is unknown. We removed an estimated 50% of annual production of alligators on Lakes Griffin and Jesup in central Florida over an 11-year period and monitored population levels via night-light counts. Densities of the total alligator population increased (P 0.117), and subadult (122-182 cm TL) alligators increased (P < 0.011) on harvest areas. The density of juveniles on the control area increased (P = 0.006), and the density of subadults showed some evidence of increasing (P = 0.088). No changes were detected in size distributions on the treatment areas. Nest production, as observed from aerial helicopter surveys, increased (P < 0.039) on Lake Woodruff NWR and Lake Jesup and showed some evidence of an increase on Lake Griffin (P = 0.098) during 1983-91. A 50% harvest rate of eggs or hatchlings did not adversely affect recruitment into the subadult or adult size classes.

  8. Preliminary report on the intestinal parasites and their diversity in captive Chinese alligators.

    PubMed

    Zhao, Jinhong; Zhou, Yongkang; Wang, Shaosheng; Tu, Genjun; Tang, Xiaoniu; Wu, Xiaobing

    2014-10-20

    Although intestinal parasites are commonly detected in either wild or farmed crocodiles in other parts of the world, yet few reports have ever been on the captive bred Chinese alligators (Alligator sinensis) since they are only distributed in the southern areas of the Yangtze River. The current work was undertaken to investigate the intestinal parasites and their diversity in the Chinese crocodilian species. In May and October of 2013, we randomly collected a total of 328 fecal samples of the captive Chinese alligators in a breeding centre in south Anhui province. Three genera of protozoa (Entaoeba, Eimeria and Isospora), five genera of nematodes (Ascaris, Dujardinascaris, Capillaria, Toxocara and Strongylus), two genera of trematodes (Echinostoma and Clonorchis) and two families of trematodes (Schistosomatidae and Cryptogonimidae) were identified, in which Dujardinascaris was the most prevalent and led to the highest infection rate (14.33%), and Entaoeba ranked the second (13.11%). The number of species, richness index, diversity index and evenness index were higher in July and August, and those indexes were relatively most in juvenile and subadult alligators. Our findings suggest that the intestinal parasites infection was prevalent in captive Chinese alligators, and this condition requires our attention, whatever it is for controlling or preventing the intestinal parasitic disease from spreading to humans or conservation of this endangered species. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  9. American alligator digestion rate of blue crabs and its implications for stomach contents analysis

    USGS Publications Warehouse

    Nifong, James C.; Rosenblatt, Adam E.; Johnson, Nathan A.; Barichivich, William; Silliman, Brian; Heithaus, Michael R.

    2012-01-01

    Stomach contents analysis (SCA) provides a snap-shot observation of a consumer's diet. Interpretation of SCA data can be complicated by many factors, including variation in gastric residence times and digestion rates among prey taxa. Although some SCA methods are reported to efficiently remove all stomach contents, the effectiveness of these techniques has rarely been tested for large irregular shaped prey with hard exoskeletons. We used a controlled feeding trial to estimate gastric residency time and decomposition rate of a large crustacean prey item, the Blue Crab (Callinectes sapidus), which is consumed by American Alligators (Alligator mississippiensis), an abundant apex predator in coastal habitats of the southeastern United States. The decomposition rate of C. sapidus in the stomachs of A. mississippiensis followed a predictable pattern, and some crab pieces remained in stomachs for at least 14 days. We also found that certain portions of C. sapidus were prone to becoming caught within the stomach or esophagus, meaning not all crab parts are consistently recovered using gastric lavage techniques. However, because the state of decomposition of crabs was predictable, it is possible to estimate time since consumption for crabs recovered from wild alligators. This information, coupled with a detailed understanding of crab distributions and alligator movement tactics could help elucidate patterns of cross-ecosystem foraging by the American Alligator in coastal habitats

  10. Animal-borne imaging reveals novel insights into the foraging behaviors and Diel activity of a large-bodied apex predator, the American alligator (Alligator mississippiensis).

    PubMed

    Nifong, James C; Nifong, Rachel L; Silliman, Brian R; Lowers, Russell H; Guillette, Louis J; Ferguson, Jake M; Welsh, Matthew; Abernathy, Kyler; Marshall, Greg

    2014-01-01

    Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here we use animal-borne imaging systems (Crittercam) to study the foraging behavior and activity patterns of a cryptic, large-bodied predator, the American alligator (Alligator mississippiensis) in two estuaries of coastal Florida, USA. Using retrieved video data we examine the variation in foraging behaviors and activity patterns due to abiotic factors. We found the frequency of prey-attacks (mean = 0.49 prey attacks/hour) as well as the probability of prey-capture success (mean = 0.52 per attack) were significantly affected by time of day. Alligators attempted to capture prey most frequently during the night. Probability of prey-capture success per attack was highest during morning hours and sequentially lower during day, night, and sunset, respectively. Position in the water column also significantly affected prey-capture success, as individuals' experienced two-fold greater success when attacking prey while submerged. These estimates are the first for wild adult American alligators and one of the few examples for any crocodilian species worldwide. More broadly, these results reveal that our understandings of crocodilian foraging behaviors are biased due to previous studies containing limited observations of cryptic and nocturnal foraging interactions. Our results can be used to inform greater understanding regarding the top-down effects of American alligators in estuarine food webs. Additionally, our results highlight the importance and power of using animal-borne imaging when

  11. Animal-Borne Imaging Reveals Novel Insights into the Foraging Behaviors and Diel Activity of a Large-Bodied Apex Predator, the American Alligator (Alligator mississippiensis)

    PubMed Central

    Nifong, James C.; Nifong, Rachel L.; Silliman, Brian R.; Lowers, Russell H.; Guillette, Louis J.; Ferguson, Jake M.; Welsh, Matthew; Abernathy, Kyler; Marshall, Greg

    2014-01-01

    Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here we use animal-borne imaging systems (Crittercam) to study the foraging behavior and activity patterns of a cryptic, large-bodied predator, the American alligator (Alligator mississippiensis) in two estuaries of coastal Florida, USA. Using retrieved video data we examine the variation in foraging behaviors and activity patterns due to abiotic factors. We found the frequency of prey-attacks (mean = 0.49 prey attacks/hour) as well as the probability of prey-capture success (mean = 0.52 per attack) were significantly affected by time of day. Alligators attempted to capture prey most frequently during the night. Probability of prey-capture success per attack was highest during morning hours and sequentially lower during day, night, and sunset, respectively. Position in the water column also significantly affected prey-capture success, as individuals’ experienced two-fold greater success when attacking prey while submerged. These estimates are the first for wild adult American alligators and one of the few examples for any crocodilian species worldwide. More broadly, these results reveal that our understandings of crocodilian foraging behaviors are biased due to previous studies containing limited observations of cryptic and nocturnal foraging interactions. Our results can be used to inform greater understanding regarding the top-down effects of American alligators in estuarine food webs. Additionally, our results highlight the importance and power of using animal

  12. American alligator proximal pedal phalanges resemble human finger bones: Diagnostic criteria for forensic investigators.

    PubMed

    Ferraro, Joseph V; Binetti, Katie M

    2014-07-01

    A scientific approach to bone and tooth identification requires analysts to pursue the goal of empirical falsification. That is, they may attribute a questioned specimen to element and taxon only after having ruled out all other possible attributions. This requires analysts to possess a thorough understanding of both human and non-human osteology, particularly so for remains that may be morphologically similar across taxa. To date, forensic anthropologists have identified several potential 'mimics' for human skeletal remains, including pig teeth and bear paws. Here we document another possible mimic for isolated human skeletal elements--the proximal pedal phalanges of American alligators (Alligator mississippiensis) closely resemble the proximal and intermediate hand phalanges of adult humans. We detail morphological similarities and differences between these elements, with the goal of providing sufficient information for investigators to confidently falsify the hypothesis that a questioned phalanx is derived from an American alligator. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Fullerene as alligator clips for electrical conduction through anthracene molecular junctions

    NASA Astrophysics Data System (ADS)

    Kaur, Rupan Preet; Sawhney, Ravinder Singh; Engles, Derick

    2017-05-01

    The conductance of a single molecule transport junction comprising anthracene molecular junction (AMJ) with fullerene as alligator clips was investigated using ab-initio density functional theory (DFT) in the Landauer-Imry regime of coherent tunnelling transport. In our previous research, we have already calculated the electrical transport properties of aromatic molecules with thiol, amine, hydroxyl and selenol end groups concluding the exceptional assistance in the formation of robust molecular junctions. In this article, we have presented the suitability of fullerene anchoring in coupling anthracene molecule with gold electrodes. AMJ with boron-20 (B-20) and C-20 alligator clips exhibited strongest conduction in contrast to nitrogen, oxygen, fluorine and neon alligator clips.

  14. The pulmonary anatomy of Alligator mississippiensis and its similarity to the avian respiratory system.

    PubMed

    Sanders, R Kent; Farmer, C G

    2012-04-01

    Using gross dissections and computed tomography we studied the lungs of juvenile American alligators (Alligator mississippiensis). Our findings indicate that both the external and internal morphology of the lungs is strikingly similar to the embryonic avian respiratory system (lungs + air sacs). We identified bronchi that we propose are homologous to the avian ventrobronchi (entobronchi), laterobronchi, dorsobronchi (ectobronchi), as well as regions of the lung hypothesized to be homologous to the cervical, interclavicular, anterior thoracic, posterior thoracic, and abdominal air sacs. Furthermore, we suggest that many of the features that alligators and birds share are homologous and that some of these features are important to the aerodynamic valve mechanism and are likely plesiomorphic for Archosauria.

  15. MicroCT Imaging on Living Alligator Teeth Reveals Natural Tooth Cycling.

    PubMed

    Widelitz, Randall B; Abdelhamid, Alaa; Khalil Khan, M; Elkarargy, Amr; Chuong, Cheng-Ming; Wu, Ping

    2017-01-01

    To study tooth cycling in polyphyodont animals, we chose to work on alligators. Alligators have teeth in three phases of development at each tooth location. This assembly of three teeth is called a tooth family unit. As part of the study, in order to study tooth cycling in alligators, we wanted to know the configuration of the tooth family unit in every tooth position. From the surface of the mouth, this is difficult to assess. Therefore, we decided to use MicroCT which can image X-ray dense materials providing a three-dimensional view. MicroCT provided us with valuable information for this study. The method described below can be applied to study tooth cycling in other vertebrate species.

  16. Antiglycation, antioxidant and toxicological potential of polyphenol extracts of alligator pepper, ginger and nutmeg from Nigeria

    PubMed Central

    Kazeem, MI; Akanji, MA; Hafizur, Rahman M; Choudhary, MI

    2012-01-01

    Objective To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg. Methods Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay. Results Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC50 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC50 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD50 4359.70 and 1490 µg/mL respectively. Conclusions It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption. PMID:23570003

  17. Antiglycation, antioxidant and toxicological potential of polyphenol extracts of alligator pepper, ginger and nutmeg from Nigeria.

    PubMed

    Kazeem, M I; Akanji, M A; Hafizur, Rahman M; Choudhary, M I

    2012-09-01

    To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg. Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay. Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC50 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC50 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD50 4359.70 and 1490 µg/mL respectively. It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption.

  18. Coplanar PCB distribution between chorioallantoic membranes and eggs of alligators and Loggerhead sea turtles

    SciTech Connect

    Bargar, T.A.; Cobb, G.P.

    1995-12-31

    The relative distribution of coplanar polychlorinated biphenyls (PCBs) between chorioallantoic membranes (CAMS) and eggs was investigated in inviable American alligator (Alligator mississippiensis) and Loggerhead sea turtle (Caretta caretra) eggs. Cam and egg extracts were fractionated by HPLC using a porous graphitic column (PGC) and an in line switching valve to separate coplanar from non-coplanar PCBs. The fractions were collected, concentrated by nitrogen evaporation, and injected on GC-ECD (60M DB-5 capillary column) for quantification. Alligator and Loggerhead sea turtle eggs contain toxicologically significant coplanar PCBs. Mono-ortho substituted PCBs were present with greater frequency relative to non-ortho substituted PCBs in both eggs and CAMS. The presence of coplanar PCBs in eggs appears to be correlated to coplanar PCB presence in CAMS. The chorioallantoic membrane could serve as a biomarker of embryo exposure to coplanar PCBs.

  19. Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis.

    PubMed

    Riede, Tobias; Tokuda, Isao T; Farmer, C G

    2011-09-15

    Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the extremely vocal avian and mammalian taxa. Anatomical studies suggest that the alligator larynx is able to abduct and adduct the vocal folds, but not to elongate or shorten them, and is therefore lacking a key regulator of frequency, yet alligators can modulate fundamental frequency remarkably well. We investigated the morphological and physiological features of sound production in alligators. Vocal fold length scales isometrically across a wide range of alligator body sizes. The relationship between fundamental frequency and subglottal pressure is significant in some individuals at some isolated points, such as call onset and position of maximum fundamental frequency. The relationship is not consistent over large segments of the call. Fundamental frequency can change faster than expected by pressure changes alone, suggesting an active motor pattern controls frequency and is intrinsic to the larynx. We utilized a two-mass vocal fold model to test whether abduction and adduction could generate this motor pattern. The fine-tuned interplay between subglottal pressure and glottal adduction can achieve frequency modulations much larger than those resulting from subglottal pressure variations alone and of similar magnitude, as observed in alligator calls. We conclude that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynx in which three parameters can be altered to modulate frequency (subglottal pressure, vocal fold adduction and length/tension).

  20. Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis

    PubMed Central

    Riede, Tobias; Tokuda, Isao T.; Farmer, C. G.

    2011-01-01

    SUMMARY Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the extremely vocal avian and mammalian taxa. Anatomical studies suggest that the alligator larynx is able to abduct and adduct the vocal folds, but not to elongate or shorten them, and is therefore lacking a key regulator of frequency, yet alligators can modulate fundamental frequency remarkably well. We investigated the morphological and physiological features of sound production in alligators. Vocal fold length scales isometrically across a wide range of alligator body sizes. The relationship between fundamental frequency and subglottal pressure is significant in some individuals at some isolated points, such as call onset and position of maximum fundamental frequency. The relationship is not consistent over large segments of the call. Fundamental frequency can change faster than expected by pressure changes alone, suggesting an active motor pattern controls frequency and is intrinsic to the larynx. We utilized a two-mass vocal fold model to test whether abduction and adduction could generate this motor pattern. The fine-tuned interplay between subglottal pressure and glottal adduction can achieve frequency modulations much larger than those resulting from subglottal pressure variations alone and of similar magnitude, as observed in alligator calls. We conclude that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynx in which three parameters can be altered to modulate frequency (subglottal pressure, vocal fold adduction and length/tension). PMID:21865521

  1. Dujardinascaris gigantea sp. n. (Nematoda: Ascaridida) from the critically endangered crocodile Alligator sinensis Fauvel (Reptilia: Crocodylia).

    PubMed

    Zhao, Jin-Hong; Li, Liang; Guo, Yan-Ning; Zhang, Lu-Ping

    2015-03-01

    The Chinese alligator Alligator sinensis Fauvel (Reptilia: Crocodylia) is considered as one of the most critically endangered species of the 23 extant crocodiles. However, our knowledge of the helminth parasites of this rare animal is completely lacking. During a helminthological survey of reptiles in China, we found a new ascaridoid nematode, Dujardinascaris gigantea sp. n. from A. sinensis. The morphology of D. gigantea sp. n. was studied using light and scanning electron microscopy. The new species was also characterised using molecular methods by sequencing and analysing the small ribosomal DNA (18S) and the second internal transcribed spacer (ITS-2).

  2. Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

  3. Dietary Selenomethionine Administration in the American Alligator (Alligator mississippiensis): Hepatic and Renal Se Accumulation and Its Effects on Growth and Body Condition.

    PubMed

    Finger, John W; Hamilton, Matthew T; Glenn, Travis C; Tuberville, Tracey D

    2017-04-01

    Selenium (Se) is an essential trace nutrient, but in excess, it can induce toxicity. Incomplete combustion of coal produces coal combustion wastes, which are enriched in Se and often disposed of in aquatic basins. While a multitude of studies have investigated Se accumulation in vertebrates, few studies have examined its effects on longer-lived top trophic carnivores, such as the American alligator (Alligator mississippiensis). In this study, alligators were fed one of three Dietary Treatments: mice injected with water (controls) or water supplemented with 1000 or 2000 ppm selenomethionine (SeMet). Dietary Treatment significantly affected Se levels in both the liver (p < 0.0001; raw mean ± SE: 1000 ppm group, 35.20 ± 6.32 ppm; 2000 ppm group, 49.97 ± 4.00 ppm) and kidney (p < 0.0001; raw mean ± SE: 1000 ppm group, 101.60 ± 8.64 ppm; 2000 ppm, 96.38 ± 5.81 ppm), which were significantly higher in alligators fed SeMet than in controls. Post-treatment head length, used to control for size variation, was negatively related to both kidney (p = 0.0142) and liver (p = 0.0010) Se concentrations. Dietary treatment with SeMet significantly reduced body condition (1000 ppm, p < 0.0029; 2000 ppm, p = 0.0075), but it significantly increased growth (1000 ppm, p < 0.0001; 2000 ppm, p = 0.0316). Body condition and growth remained unchanged in control alligators (p > 0.05). Our results demonstrate alligators are capable of accumulating high levels of Se through trophic transfer. The positive effects of accumulation on growth may demonstrate Se essentiality, whereas the negative effects on condition may demonstrate toxicity. Accumulation also was associated with mortality, further demonstrating toxicity. Future studies should further investigate the physiological effects of Se accumulation in long-lived, top-trophic carnivores.

  4. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    SciTech Connect

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; Tuberville, Tracey D.

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3₋), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. In conclusion, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood.

  5. Alterations in eicosanoid composition during embryonic development in the chorioallantoic membrane of the American alligator (Alligator mississippiensis) and domestic chicken (Gallus gallus).

    PubMed

    Cantu, Theresa M; Bowden, John A; Scott, Jacob; Pérez-Viscasillas, Jimena B; Huncik, Kevin; Guillette, Matthew P; Guillette, Louis J

    2016-11-01

    Eicosanoids are signaling lipids known to regulate several physiological processes in the mammalian placenta, including the initiation of parturition. Though all amniotes construct similar extraembryonic membranes during development, the composition and function of eicosanoids in extraembryonic membranes of oviparous reptiles is largely unknown. The majority of effort placed in eicosanoid investigations is typically targeted toward defining the role of specific compounds in disease etiology; however, comprehensive characterization of several pathways in eicosanoid synthesis during development is also needed to better understand the complex role of these lipids in comparative species. To this end, we have examined the chorioallantoic membrane (CAM) of the American alligator (Alligator mississippiensis) and domestic chicken (Gallus gallus) during development. Previously, our lab has demonstrated that the CAM of several oviparous species shared conserved steroidogenic activity, a feature originally attributed to mammalian amniotes. To further explore this, we have developed a liquid chromatography/tandem mass spectrometry method that is used here to quantify multiple eicosanoids in the CAM of two oviparous species at different stages of development. We identified 18 eicosanoids in the alligator CAM; the cyclooxygenase (COX) pathway showed the largest increase from early development to later development in the alligator CAM. Similarly, the chicken CAM had an increase in COX products and COX activity, which supports the LC-MS/MS analyses. Jointly, our findings indicate that the CAM tissue of an oviparous species is capable of eicosanoid synthesis, which expands our knowledge of placental evolution and introduces the possibility of future comparative models of placental function. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    DOE PAGES

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; ...

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressuremore » of carbon dioxide (PCO2), bicarbonate (HCO3₋), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. In conclusion, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood.« less

  7. Surgical removal of right-to-left cardiac shunt in the American alligator (Alligator mississippiensis) causes ventricular enlargement but does not alter apnoea or metabolism during diving.

    PubMed

    Eme, John; Gwalthney, June; Blank, Jason M; Owerkowicz, Tomasz; Barron, Gildardo; Hicks, James W

    2009-11-01

    Crocodilians have complete anatomical separation between the ventricles, similar to birds and mammals, but retain the dual aortic arch system found in all non-avian reptiles. This cardiac anatomy allows surgical modification that prevents right-to-left (R-L) cardiac shunt. A R-L shunt is a bypass of the pulmonary circulation and recirculation of oxygen-poor blood back to the systemic circulation and has often been observed during the frequent apnoeic periods of non-avian reptiles, particularly during diving in aquatic species. We eliminated R-L shunt in American alligators (Alligator mississippiensis) by surgically occluding the left aorta (LAo; arising from right ventricle) upstream and downstream of the foramen of Panizza (FoP), and we tested the hypotheses that this removal of R-L shunt would cause afterload-induced cardiac remodelling and adversely affect diving performance. Occlusion of the LAo both upstream and downstream of the FoP for approximately 21 months caused a doubling of RV pressure and significant ventricular enlargement (average approximately 65%) compared with age-matched, sham-operated animals. In a separate group of recovered, surgically altered alligators allowed to dive freely in a dive chamber at 23 degrees C, occlusion of the LAo did not alter oxygen consumption or voluntary apnoeic periods relative to sham animals. While surgical removal of R-L shunt causes considerable changes in cardiac morphology similar to aortic banding in mammals, its removal does not affect the respiratory pattern or metabolism of alligators. It appears probable that the low metabolic rate of reptiles, rather than pulmonary circulatory bypass, allows for normal aerobic dives.

  8. Follicle-stimulating hormone receptor (FSHR) in Chinese alligator, Alligator sinensis: molecular characterization, tissue distribution and mRNA expression changes during the female reproductive cycle.

    PubMed

    Zhang, Rui; Zhang, Shengzhou; Zhu, Xue; Zhou, Yongkang; Wu, Xiaobing

    2015-05-01

    The follicle-stimulating hormone (FSH) plays a central role in vertebrate reproduction, with the actions of FSH mediated by FSH receptors (FSHRs) on the granulosa cells of the ovary. The present study reports the cloning and characterization of FSHR in Chinese alligator, Alligator sinensis (caFSHR), and its tissue distribution and mRNA expression changes during the reproductive cycle. The mature protein of caFSHR displays typical features of the glycoprotein hormone receptor family, but also contains some remarkable differences when compared with other vertebrate FSHRs. The deduced amino acid sequence of the caFSHR shares identity of 85% with Chinese softshell turtle, 84-87% with birds, 77-78% with mammals, 67-73% with amphibians and 51-58% with fishes. Phylogenetic tree analysis of the FSHR amino acid sequence indicated that alligators cluster into the bird branch. Tissue expression analysis showed that caFSHR was not only expressed in the ovary, but also in the stomach, intestine, pancreas liver and oviduct at similar levels, while it was not detectable in heart, thymus or thyroid. Expression of caFSHR in the ovary is high in May (breeding prophase) and peaks in July during the breeding period, where it is maintained at high levels through September (breeding anaphase). Expression decreases significantly in November (hibernating period) and then remains relatively low from January to March (hibernating period). These temporal changes in FSHR expression suggest that it plays an important role in promoting ovarian development during the female reproductive cycle of Chinese alligator.

  9. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    PubMed Central

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; Tuberville, Tracey D.

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3−), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. Lastly, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood. PMID:27382469

  10. Surgical removal of right-to-left cardiac shunt in the American alligator (Alligator mississippiensis) causes ventricular enlargement but does not alter apnoea or metabolism during diving

    PubMed Central

    Eme, John; Gwalthney, June; Blank, Jason M.; Owerkowicz, Tomasz; Barron, Gildardo; Hicks, James W.

    2009-01-01

    SUMMARY Crocodilians have complete anatomical separation between the ventricles, similar to birds and mammals, but retain the dual aortic arch system found in all non-avian reptiles. This cardiac anatomy allows surgical modification that prevents right-to-left (R–L) cardiac shunt. A R–L shunt is a bypass of the pulmonary circulation and recirculation of oxygen-poor blood back to the systemic circulation and has often been observed during the frequent apnoeic periods of non-avian reptiles, particularly during diving in aquatic species. We eliminated R–L shunt in American alligators (Alligator mississippiensis) by surgically occluding the left aorta (LAo; arising from right ventricle) upstream and downstream of the foramen of Panizza (FoP), and we tested the hypotheses that this removal of R–L shunt would cause afterload-induced cardiac remodelling and adversely affect diving performance. Occlusion of the LAo both upstream and downstream of the FoP for ∼21 months caused a doubling of RV pressure and significant ventricular enlargement (average ∼65%) compared with age-matched, sham-operated animals. In a separate group of recovered, surgically altered alligators allowed to dive freely in a dive chamber at 23°C, occlusion of the LAo did not alter oxygen consumption or voluntary apnoeic periods relative to sham animals. While surgical removal of R–L shunt causes considerable changes in cardiac morphology similar to aortic banding in mammals, its removal does not affect the respiratory pattern or metabolism of alligators. It appears probable that the low metabolic rate of reptiles, rather than pulmonary circulatory bypass, allows for normal aerobic dives. PMID:19837897

  11. Molecular cloning and characterization of the corticoid receptors from the American alligator.

    PubMed

    Oka, Kaori; Kohno, Satomi; Urushitani, Hiroshi; Guillette, Louis J; Ohta, Yasuhiko; Iguchi, Taisen; Katsu, Yoshinao

    2013-01-30

    Steroid hormones are essential for health in vertebrates. Corticosteroids, for example, have a regulatory role in many physiological functions, such as osmoregulation, respiration, immune responses, stress responses, reproduction, growth, and metabolism. Although extensively studied in mammals and some non-mammalian species, the molecular mechanisms of corticosteroid hormone (glucocorticoids and mineralocorticoids) action are poorly understood in reptiles. Here, we have evaluated hormone receptor-ligand interactions in the American alligator (Alligator mississippiensis), following the isolation of cDNAs encoding a glucocorticoid receptor (GR) and a mineralocorticoid receptor (MR). The full-length alligator GR (aGR) and aMR cDNAs were obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequences exhibited high identity to the chicken orthologs (aGR: 83%; aMR: 90%). Using transient transfection assays of mammalian cells, both aGR and aMR proteins displayed corticosteroid-dependent activation of transcription from keto-steroid hormone responsive, murine mammary tumor virus promoters. We further compared the ligand-specifity of human, chicken, Xenopus, and zebrafish GR and MR. We found that the alligator and chicken GR/MR have very similar amino acid sequences, and this translates to very similar ligand specificity. This is the first report of the full-coding regions of a reptilian GR and MR, and the examination of their transactivation by steroid hormones. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. The evolutionary history of an invasive species: alligator weed, Alternanthera philoxeroides

    USDA-ARS?s Scientific Manuscript database

    The eco-evolutionary mechanisms of biological invasions are still not thoroughly understood. Alligator weed, Alternanthera philoxeroides (Martius) Gisebach (Amaranthaceae), is a plant native to South America and a weed in Australia and other countries. To better understand its success as an invader,...

  13. High Resolution Electron Microbeam Examination and 3D Reconstruction of Alligator Gar Scale

    DTIC Science & Technology

    2016-06-27

    Figure 1a. Alligator Gar fish caught in Brazos River, Texas. Six feet long and 129 lbs. Credit : Clinton and Charles Robertson https://www.flickr.com...photos/dad_and_clint/12716099/in/album-72057594067873642/ Figure 1b. Gar fish scales. Credit : http://shadyufo.tumblr.com/post/35927882044/gar-fish

  14. A group of alligators basks in the sun and rest in the water at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This pond near Schwartz Rd. at Kennedy Space Center is host to a least the nine alligators shown on the banks and in the water. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  15. Achieving environmentally relevant organochlorine pesticide concentrations in eggs through maternal exposure in Alligator mississippiensis

    USGS Publications Warehouse

    Rauschenberger, R.H.; Wiebe, J.J.; Buckland, J.E.; Smith, Joe T.; Sepulveda, M.S.; Gross, T.S.

    2004-01-01

    Alligator mississippiensis eggs from organochlorine pesticide (OCP) contaminated sites in Florida exhibit high rates of embryonic mortality compared to reference sites (p<0.05). The objective of the present study was to use captive adult alligators to test the hypotheses that maternal exposure to OCPs results in increased OCP concentrations in eggs, and that increased exposure is associated with increased embryonic mortality. A total of 24 adult alligators (8 males and 16 females) were housed in eight pens. Eight females in four pens were dosed with a mixture of p,p'-DDE, toxaphene, dieldrin, and chlordane at a rate of 0.2 ? 0.01 mg/kg/day for 274 ? 8 days. Treated females produced eggs containing higher OCP concentrations (12,814 ? 813 ng/g yolk) than controls (38 ? 4 ng/g yolk). Eggs of treated females exhibited decreased viability (13 ? 22%) as compared to controls (45 ? 20%). Results indicated that 0.6% of administered OCPs were maternally transferred to the eggs of American alligators, and that maternal exposure is associated with decreased egg/embryo viability in this species.

  16. A group of alligators basks in the sun and rest in the water at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This pond near Schwartz Rd. at Kennedy Space Center is host to a least the nine alligators shown on the banks and in the water. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  17. Effects of salinity on growth and ion regulation of juvenile alligator gar Atractosteus spatula

    USDA-ARS?s Scientific Manuscript database

    The alligator gar (Atractosteus spatula) is a primitive euryhaline fish, found primarily in estuaries and freshwater drainages associated with the northern Gulf of Mexico. The extent of its hypo-osmotic regulatory abilities is not well understood. In order to determine how salinity affects growth ra...

  18. AHR and CYP1A expression link historical contamination events to modern day developmental effects in the American alligator.

    PubMed

    Hale, Matthew D; Galligan, Thomas M; Rainwater, Thomas R; Moore, Brandon C; Wilkinson, Philip M; Guillette, Louis J; Parrott, Benjamin B

    2017-11-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that initiates a transcriptional pathway responsible for the expression of CYP1A subfamily members, key to the metabolism of xenobiotic compounds. Toxic planar halogenated aromatic hydrocarbons, including dioxin and PCBs, are capable of activating the AHR, and while dioxin and PCB inputs into the environment have been dramatically curbed following strict regulatory efforts in the United States, they persist in the environment and exposures remain relevant today. Little is known regarding the effects that long-term chronic exposures to dioxin or dioxin-like compounds might have on the development and subsequent health of offspring from exposed individuals, nor is much known regarding AHR expression in reptilians. Here, we characterize AHR and CYP1A gene expression in embryonic and juvenile specimen of a long-lived, apex predator, the American alligator (Alligator mississippiensis), and investigate variation in gene expression profiles in offspring collected from sites conveying differential exposures to environmental contaminants. Both age- and tissue-dependent patterning of AHR isoform expression are detected. We characterize two downstream transcriptional targets of the AHR, CYP1A1 and CYP1A2, and describe conserved elements of their genomic architecture. When comparisons across different sites are made, hepatic expression of CYP1A2, a direct target of the AHR, appears elevated in embryos from a site associated with a dioxin point source and previously characterized PCB contamination. Elevated CYP1A2 expression is not persistent, as site-specific variation was absent in juveniles originating from field-collected eggs but reared under lab conditions. Our results illustrate the patterning of AHR gene expression in a long-lived environmental model species, and indicate a potential contemporary influence of historical contamination. This research presents a novel opportunity to link

  19. Simple solar technology saves money for alligator farms

    SciTech Connect

    Goldman, A.

    1993-01-01

    In 1990, a high-volume solar thermal water-heating system in Florida was installed in Okeechobee County by Solar Development, Inc. (SDI). The system is designed to provide large quantities of hot water for commercial use and heat water to as high as 140[degrees]F. The design in Florida is known as a Shallow Solar Pond (SSP). It was completed with the help of the Florida Alligator Farmers Association, the Florida Energy Office, Foster Farms, and SDI. The SSP is a modular system built on site and modified to meet the specific needs of each application. The tank and the collector are the same unit, which keeps the system cost very low. The typical SSP module is 16 feet wide and up to 200 feet long. The module contains one or two reinforced-rubber flat water bags similar to a water bed. The bags rest on a layer of insulation or sand inside concrete or fiberglass curbs. In the Foster Farms SSP, the insulation was omitted and the water bags are placed on sand. The bag is protected against damage and heat loss by greenhouse-type glazing. At Foster Farms there are 3 SSPs, set in approximately 8,000 square feet, with two 5,000-gallon bags per unit. In addition, there is a pressurizing pump/tank system. Every morning, the heated water from the bags drains into a sump tank. While the bags are emptied into the backup system, well water is pumped in and the solar heating process starts all over again.

  20. The Good, the Bad, and the Unknown: Microbial Symbioses of the American Alligator.

    PubMed

    Keenan, Sarah W; Elsey, Ruth M

    2015-12-01

    Vertebrates coexist with microorganisms in diverse symbiotic associations that range from beneficial to detrimental to the host. Most research has aimed at deciphering the nature of the composite microbial assemblage's genome, or microbiome, from the gastrointestinal (GI) tract and skin of mammals (i.e., humans). In mammals, the GI tract's microbiome aids digestion, enhances uptake of nutrients, and prevents the establishment of pathogenic microorganisms. However, because the GI tract microbiome of the American alligator (Alligator mississippiensis) is distinct from that of all other vertebrates studied to date, being comprised of Fusobacteria in the lower GI tract with lesser abundances of Firmicutes, Proteobacteria, and Bacteroidetes, the function of these assemblages is largely unknown. This review provides a synthesis of our current understanding of the composition of alligators' microbiomes, highlights the potential role of microbiome members in alligators' health (the good), and presents a brief summary of microorganisms detrimental to alligators' health (the bad) including Salmonella spp. and others. Microbial assemblages of the GI tract have co-evolved with their vertebrate host over geologic time, which means that evolutionary hypotheses can be tested using information about the microbiome. For reptiles and amphibians, the number of taxa studied at present is limited, thereby restricting evolutionary insights. Nevertheless, we present a compilation of our current understanding of reptiles' and amphibians' microbiomes, and highlight future avenues of research (the unknown). As in humans, composition of microbiome assemblages provides a promising tool for assessing hosts' health or disease. By further exploring present-day associations between symbiotic microorganisms in the microbiomes of reptiles and amphibians, we can better identify good (beneficial) and bad (detrimental) microorganisms, and unravel the evolutionary history of the acquisition of

  1. The oldest record of Alligator sinensis from the Late Pliocene of Western Japan, and its biogeographic implication

    NASA Astrophysics Data System (ADS)

    Iijima, Masaya; Takahashi, Keiichi; Kobayashi, Yoshitsugu

    2016-07-01

    The late Cenozoic fossil record of alligators in East Asia is crucial in understanding the origin and past distribution of Asian alligators that are now represented by a single species, Alligator sinensis. This study reports a partial skeleton of A. sinensis from the Late Pliocene (approximately 3.0 Ma) of western Japan. This Japanese A. sinensis is large in size (>200 cm total length), comparable to the maximum size of extant individuals. It demonstrates the oldest record of A. sinensis and wider distribution of this species in the past. Tectonic and geographic history of East Asia suggests that alligators presumably dispersed into Japan before 25 Ma or after 10 Ma, yet finally were wiped out from Japan due to the semi-isolated condition of the Japanese island arc and the deteriorated climate during the Plio-Pleistocene.

  2. Conservation genetics of the alligator snapping turtle: cytonuclear evidence of range-wide bottleneck effects and unusually pronounced geographic structure

    USGS Publications Warehouse

    Echelle, A.A.; Hackler, J.C.; Lack, Justin B.; Ballard, S. R.; Roman, J.; Fox, S. F.; Leslie,, David M.; Van Den Bussche, Ronald A.

    2010-01-01

    A previous mtDNA study indicated that female-mediated gene flow was extremely rare among alligator snapping turtle populations in different drainages of the Gulf of Mexico. In this study, we used variation at seven microsatellite DNA loci to assess the possibility of male-mediated gene flow, we augmented the mtDNA survey with additional sampling of the large Mississippi River System, and we evaluated the hypothesis that the consistently low within-population mtDNA diversity reflects past population bottlenecks. The results show that dispersal between drainages of the Gulf of Mexico is rare (F STmsat  = 0.43, ΦSTmtDNA = 0.98). Past range-wide bottlenecks are indicated by several genetic signals, including low diversity for microsatellites (1.1–3.9 alleles/locus; H e = 0.06–0.53) and mtDNA (h = 0.00 for most drainages; π = 0.000–0.001). Microsatellite data reinforce the conclusion from mtDNA that the Suwannee River population might eventually be recognized as a distinct taxonomic unit. It was the only population showing fixation or near fixation for otherwise rare microsatellite alleles. Six evolutionarily significant units are recommended on the basis of reciprocal mtDNA monophyly and high levels of microsatellite DNA divergence.

  3. KENNEDY SPACE CENTER, FLA. -- An alligator is spotted sunning on the muddy bank of a canal in KSC. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the surrounding Merritt Island National Wildlife Refuge. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles.

    NASA Image and Video Library

    2004-01-08

    KENNEDY SPACE CENTER, FLA. -- An alligator is spotted sunning on the muddy bank of a canal in KSC. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the surrounding Merritt Island National Wildlife Refuge. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles.

  4. EAARL coastal topography--Alligator Point, Louisiana, 2010

    USGS Publications Warehouse

    Nayegandhi, Amar; Bonisteel-Cormier, J.M.; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Fredericks, Xan; Barras, J.A.

    2012-01-01

    This project provides highly detailed and accurate datasets of a portion of Alligator Point, Louisiana, acquired on March 5 and 6, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the National Aeronautics and Space Administration (NASA) Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have

  5. Herpetofaunal diversity of Alligator River National Wildlife Refuge, North Carolina

    USGS Publications Warehouse

    Meyers, J.M.; Pike, D.A.

    2006-01-01

    In the past century, habitat alteration and fragmentation have increased dramatically, which increases the need for improving our understanding of how species and biological communities react to these modifications. A national strategy on biological diversity has focused attention on how these habitat modifications affect species, especially herpetofauna (i.e., changes in species richness, community evenness and similarity, and dominant/rare species). As part of this strategy, we surveyed Alligator River National Wildlife Refuge, a coastal, mixed second-growth forested swamp (MFS) and pocosin wetland (PW), in North Carolina for amphibians and reptiles from September 2000 to August 2001. We randomly selected three sites (3 x 3 km) in two major habitat types (MFS, PW) and completed random surveys and trapping using transects, quadrats, nighttime aural road surveys, drift fences, canal transects, coverboards, incidental captures, and evening road surveys. We also collected herpetofauna opportunistically throughout the refuge to establish an updated species list. For analysis, we used Shannon-Weiner species diversity (H'), evenness (1'), species richness and species detectability (COMDYN4), and community percent similarity index to determine herpetofaunal community differences. We estimated 39 species in MFS and 32 species in PW (P < 0.10). Species detectability was similar between habitats (0.84 to 0.86). More reptilian species (+ 31 %) inhabited MFS than PW, but estimated amphibian species richness was identical (17 spp.). H' was higher (P < 0.000 I) for PW (2.6680) than for MFS (2.1535) because of lower J' in the latter (0.6214 vs. 0.8010). Dominance of three Rana species caused lower J' and H' in MFS. Similarity between the communities was 56.6%; we estimated 22-24 species in common for each habitat (95% CI = 18 to 31 spp.). We verified 49 of the 52 herpetofaunal species on the refuge that were known to exist in the area. Restoration of natural water flows may

  6. Insulin-like growth factor I (IGF-I) in Chinese alligator, Alligator sinensis: Molecular characterization, tissue distribution and mRNA expression changes during the active and hibernating periods.

    PubMed

    Zhu, Xue; Zhang, Shengzhou; Zhao, Shuai; Zhang, Rui; Zhou, Yongkang; Wu, Xiaobing

    2017-02-01

    The Chinese alligator Alligator sinensis is an endangered species endemic to China, up to date, little is known about the regulation of its growth and development. Insulin-like growth factor I (IGF-I) plays a vital role in regulating vertebrate growth and development. In this study, the full-length cDNA of IGF-I in Chinese alligator (caIGF-I) was obtained for the first time, it contains 890-bp nucleotides encoding a 153-amino acid precursor, the mature caIGF-I consists of 70 amino acids by cleaving the signal peptide and C-terminal extension (E domain). The caIGF-I contains all the features of IGF-I peptide with B, C, A, and D domains and the six conservative cysteine residues involved in the stable tertiary structure. Multiple alignment analysis showed that the amino acid sequence of caIGF-I shares high identity with American alligator Alligator mississippiensis (100%) and birds (95-97%). Phylogenetic tree analysis of the IGF-I amino acid sequences indicated that alligators cluster into the bird branch. Real-time quantitative PCR technique showed that caIGF-I is widely expressed in all the examined tissues with the highest expression level in liver, higher in pancreas and oviduct while lower in heart, spleen, lung, kidney, stomach, intestines, ovary and muscles. During hibernation, the caIGF-I expression level decreased significantly in liver, pancreas, oviduct and kidney, while did not significantly change in heart, spleen, lung, stomach, small intestine, ovary and muscles. The mRNA expression changes during the two periods implicate that caIGF-I might play an important role in the regulation of feeding and growth in the Chinese alligator.

  7. Mechanics of limb bone loading during terrestrial locomotion in the green iguana (Iguana iguana) and American alligator (Alligator mississippiensis).

    PubMed

    Blob, R W; Biewener, A A

    2001-03-01

    In vivo measurements of strain in the femur and tibia of Iguana iguana (Linnaeus) and Alligator mississippiensis (Daudin) have indicated three ways in which limb bone loading in these species differs from patterns observed in most birds and mammals: (i) the limb bones of I. iguana and A. mississippiensis experience substantial torsion, (ii) the limb bones of I. iguana and A. mississippiensis have higher safety factors than those of birds or mammals, and (iii) load magnitudes in the limb bones of A. mississippiensis do not decrease uniformly with the use of a more upright posture. To verify these patterns, and to evaluate the ground and muscle forces that produce them, we collected three-dimensional kinematic and ground reaction force data from subadult I. iguana and A. mississippiensis using a force platform and high-speed video. The results of these force/kinematic studies generally confirm the loading regimes inferred from in vivo strain measurements. The ground reaction force applies a torsional moment to the femur and tibia in both species; for the femur, this moment augments the moment applied by the caudofemoralis muscle, suggesting large torsional stresses. In most cases, safety factors in bending calculated from force/video data are lower than those determined from strain data, but are as high or higher than the safety factors of bird and mammal limb bones in bending. Finally, correlations between limb posture and calculated stress magnitudes in the femur of I. iguana confirm patterns observed during direct bone strain recordings from A. mississippiensis: in more upright steps, tensile stresses on the anterior cortex decrease, but peak compressive stresses on the dorsal cortex increase. Equilibrium analyses indicate that bone stress increases as posture becomes more upright in saurians because the ankle and knee extensor muscles exert greater forces during upright locomotion. If this pattern of increased bone stress with the use of a more upright posture is

  8. Water hyacinths and alligator weeds for removal of lead and mercury from polluted waters

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water hyacinths demonstrated the ability to remove 0.176 mg of lead and 0.150 mg of mercury per gram of dry plant material from distilled water and river water in a 24-hour period. One acre of water hyacinths is potentially capable of removing 105.6 grams of lead and 90.0 grams of mercury per day. Alligator weeds removed 0.101 mg of lead per gram of dry plant material in a 24-hour period. This same plant also demonstrated the ability to remove a minimum of 0.153 mg of mercury per gram of dry plant material in a six hour period.

  9. Hydrodynamic analysis, performance assessment, and actuator design of a flexible tail propulsor in an artificial alligator

    NASA Astrophysics Data System (ADS)

    Philen, Michael; Neu, Wayne

    2011-09-01

    The overall objective of this research is to develop analysis tools for determining actuator requirements and assessing viable actuator technology for design of a flexible tail propulsor in an artificial alligator. A simple hydrodynamic model that includes both reactive and resistive forces along the tail is proposed and the calculated mean thrust agrees well with conventional estimates of drag. Using the hydrodynamic model forces as an input, studies are performed for an alligator ranging in size from 1 cm to 2 m at swimming speeds of 0.3-1.8 body lengths per second containing five antagonistic pairs of actuators distributed along the length of the tail. Several smart materials are considered for the actuation system, and preliminary analysis results indicate that the acrylic electroactive polymer and the flexible matrix composite actuators are potential artificial muscle technologies for the system.

  10. Determining the size of American alligators using hind-foot track length

    USGS Publications Warehouse

    Wilkinson, Philip M.; Rice, Kenneth G.

    2000-01-01

    Size distribution information is useful for crocodilian management, but can be hard to obtain. Indirect and less costly demographic inferences made from track measurements may be valuable for management decisions. We related hind-foot lengths (HF) with total length (TL) to determine if we could indirectly assess alligator size using track length. Regression showed that HF was an excellent predictor (F1,246= 15722.9, R2=0.98, P<0.01) of TL and track length was an exceptional predictor of HF (F1,14=7520.3, R2= 1.00, P<0.01). The correlation between track length and HF length also was significant (N= 15, r=0.99, P <0.01). Thus, alligator size can be accurately estimated from measures of track length at sites where capture and direct measurement is impractical.

  11. Contaminants in American alligator eggs from Lake Apopka, Lake Griffin, and Lake Okeechobee, Florida

    USGS Publications Warehouse

    Heinz, G.H.; Percival, H.F.; Jennings, Michael L.

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A larger sample of eggs was collected in 1985, but only from Lakes Griffin, a lake where eggs were relatively clean, and Apopka, where eggs were most contaminated. In 1985, hatching success of artificially incubated eggs was lower for Lake Apopka, and several organochlorine pesticides were higher than in eggs from Lake Griffin. However, within Lake Apopka, higher levels of pesticides in chemically analyzed eggs were not associated with reduced hatching success of the remaining eggs in the clutch. Therefore, it did not appear that any of the pesticides we measured were responsible for the reduced hatching of Lake Apopka eggs.

  12. WILDLIFE - ALLIGATOR NAMED KASEY LIVES IN POND IN FRONT OF HEADQUARTERS

    NASA Technical Reports Server (NTRS)

    1969-01-01

    A big, toothy saurian grin is flashed by this alligator in the pond in front of the KSC Headquarters Building. And wy not? After years of namelessness, he [or she] has a name. The 'gator was dubbed Kasey following a ''Name the Gator'' contest in which scores of Spaceport employees submitted name suggestions. Kasey is one of two 'gators placed in the pond in an attempt to restore its natural ecology.

  13. Microsatellite DNA analyses support an east-west phylogeographic split of American alligator populations.

    PubMed

    Davis, Lisa M; Glenn, Travis C; Strickland, Denise C; Guillette, Louis J; Elsey, Ruth M; Rhodes, Walter E; Dessauer, Herbert C; Sawyer, Roger H

    2002-12-15

    We examined the population genetic structure of American alligators (Alligator mississippiensis) sampled from 12 localities across the southeastern United States. The primary goal of this study was to determine the extent of population differentiation among alligators from four Florida lakes using eight microsatellite loci and compare the results to additional sites located at varying distances from them. Analyses of population structure revealed little differentiation (F(ST)=0.039; Rho=0.012) among the four Florida lakes, Apopka, Griffin, Orange and Woodruff, which are all located in the St. John&'s River watershed in north-central Florida. Further, there was little differentiation among these samples and samples collected from the Everglades National Park (F(ST)=0.044; Rho=0.009) and south Georgia (F(ST)=0.045; Rho=0.032). Therefore, these six samples were pooled together as a "FL/sGA group." Similarly, samples collected in the western extent of the range, Anahuac National Wildlife Refuge in Texas and Salvador Wildlife Management Area, Marsh Island Wildlife Refuge and Rockefeller Wildlife Refuge in Louisiana, also lacked population structure (F(ST)=0.024; R(ST)=0.040). These four populations were pooled into the "TX/LA group." Comparisons of these two groups with samples taken from the Santee Coastal Reserve in South Carolina and Mobile, Alabama yielded three to four times more differentiation among groups (F(ST)=0.131; Rho=0.187). These and other analyses support the hypothesis of an east-west phylogeographic split in American alligator populations and are consistent with studies of many freshwater fish and aquatic and terrestrial turtles distributed throughout this same geographic region.

  14. Nutrient and organochlorine pesticide concentrations in American alligator eggs and their associations with clutch viability.

    PubMed

    Rauschenberger, R Heath; Sepúlveda, Maria S; Wiebe, Jon J; Wiebe, Janet E; Honeyfield, Dale C; Gross, Timothy S

    2009-12-01

    Since the early 1900s, the lakes of the Ocklawaha basin in central Florida have experienced ecological degradation due to anthropogenic development. One species affected by this degradation is the American alligator Alligator mississippiensis, which has suffered from poor clutch viability and embryo mortality. Although some studies indicate that organochlorine pesticides (OCPs) may be involved, OCPs do not account for all of the variation seen in hatch rates. Indeed, nutrition and non-OCP contaminants have been associated with developmental problems in fish and birds. Our study evaluated embryo mortality in alligators at reference and OCP-contaminated sites as a function of exposure to OCPs, polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs), along with egg nutrients (Zn, Se, and vitamins A, E, and B1). The four-pronged study consisted of a case-control cohort study, an expanded field study, a topical egg treatment thiamine amelioration experiment, and a topical egg treatment thiamine antagonist experiment. The results from the two field studies suggested that the total thiamine levels in the eggs were positively associated with clutch viability and negatively associated with the lipid content and certain OCPs measured in egg yolks. In addition, PCBs, PAHs, Zn, Se, and vitamins A and E were not found to be associated with the observed clutch viability defects. The thiamine levels in the eggs explained 38% of the variation in clutch survival in the case-control cohort study and 27% in the expanded field study. The topical egg treatment experiments were successful in elevating the thiamine concentrations in the albumin but not the yolk. No significant differences were noted among treatment groups in either egg treatment experiment with respect to clutch survival. In summary, thiamine egg concentrations explain some of the variation in the clutch viability of free-ranging alligators, but the cause-effect relationships are still unclear.

  15. Temperature has species-specific effects on corticosterone in alligator lizards.

    PubMed

    Telemeco, Rory S; Addis, Elizabeth A

    2014-09-15

    In response to conditions that threaten homeostasis and/or life, vertebrates generally increase production of glucocorticoid hormones, such as corticosterone (CORT), which induces an emergency physiological state referred to as the stress response. Given that extreme temperatures pose a threat to performance and survival, glucocorticoid upregulation might be an important component of a vertebrate ectotherm's response to extreme thermal conditions. To address this hypothesis, we experimentally examined the effects of body temperature (10, 20, 28, and 35°C; 5-h exposure) on CORT in two congeneric species of lizard naturally exposed to different thermal environments, northern and southern alligator lizards (Elgaria coerulea and Elgaria multicarinata, respectively). In both species, CORT was similarly elevated at medium and high temperatures (28 and 35°C, respectively), but CORT was only elevated at low temperatures (10°C) in southern alligator lizards. We also examined CORT before and after adrenocorticotrophic hormone (ACTH) challenge. In both species, ACTH induced higher CORT levels than any temperature, suggesting that these animals could respond to further stressors at all experimental temperatures. Finally, we compared our laboratory results to measurements of CORT in field-active southern alligator lizards. Plasma CORT concentrations from our laboratory experiment had the same mean and less variance than the field lizards, suggesting that our laboratory lizards displayed CORT within natural levels. Our results demonstrate that body temperature directly affects CORT in alligator lizards. Moreover, the CORT response of these lizards appears to be adapted to their respective thermal environments. Species-specific differences in the thermal CORT response might be common in vertebrate ectotherms and have implications for species' biogeography and responses to climate change. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. WILDLIFE - ALLIGATOR NAMED KASEY LIVES IN POND IN FRONT OF HEADQUARTERS

    NASA Technical Reports Server (NTRS)

    1969-01-01

    A big, toothy saurian grin is flashed by this alligator in the pond in front of the KSC Headquarters Building. And wy not? After years of namelessness, he [or she] has a name. The 'gator was dubbed Kasey following a ''Name the Gator'' contest in which scores of Spaceport employees submitted name suggestions. Kasey is one of two 'gators placed in the pond in an attempt to restore its natural ecology.

  17. Functional morphology of the Alligator mississippiensis larynx with implications for vocal production.

    PubMed

    Riede, Tobias; Li, Zhiheng; Tokuda, Isao T; Farmer, Colleen G

    2015-04-01

    Sauropsid vocalization is mediated by the syrinx in birds and the larynx in extant reptiles; but whereas avian vocal production has received much attention, the vocal mechanism of basal reptilians is poorly understood. The American alligator (Alligator mississippiensis) displays a large vocal repertoire during mating and in parent-offspring interactions. Although vocal outputs of these behaviors have received some attention, the underlying mechanism of sound production remains speculative. Here, we investigate the laryngeal anatomy of juvenile and adult animals by macroscopic and histological methods. Observations of the cartilaginous framework and associated muscles largely corroborate earlier findings, but one muscle, the cricoarytenoideus, exhibits a heretofore unknown extrinsic insertion that has important implications for effective regulation of vocal fold length and tension. Histological investigation of the larynx revealed a layered vocal fold morphology. The thick lamina propria consists of non-homogenous extracellular matrix containing collagen fibers that are tightly packed below the epithelium but loosely organized deep inside the vocal fold. We found few elastic fibers but comparatively high proportions of hyaluronan. Similar organizational complexity is also seen in mammalian vocal folds and the labia of the avian syrinx: convergent morphologies that suggest analogous mechanisms for sound production. In tensile tests, alligator vocal folds demonstrated a linear stress-strain behavior in the low strain region and nonlinear stress responses at strains larger than 15%, which is similar to mammalian vocal fold tissue. We have integrated morphological and physiological data in a two-mass vocal fold model, providing a systematic description of the possible acoustic space that could be available to an alligator larynx. Mapping actual call production onto possible acoustic space validates the model's predictions. © 2015. Published by The Company of Biologists

  18. Estimating spawning times of Alligator Gar (Atractosteus spatula) in Lake Texoma, Oklahoma

    USGS Publications Warehouse

    Snow, Richard A.; Long, James M.

    2015-01-01

    In 2013, juvenile Alligator Gar were sampled in the reservoir-river interface of the Red River arm of Lake Texoma. The Red River, which flows 860 km along Oklahoma’s border with Texas, is the primary in-flow source of Lake Texoma, and is impounded by Denison Dam. Minifyke nets were deployed using an adaptive random cluster sampling design, which has been used to effectively sample rare species. Lapilli otoliths (one of the three pair of ear stones found within the inner ear of fish) were removed from juvenile Alligator Gar collected in July of 2013. Daily ages were estimated by counting the number of rings present, and spawn dates were back-calculated from date of capture and subtracting 8 days (3 days from spawn to hatch and 5 days from hatch to swimup when the first ring forms). Alligator Gar daily age estimation ranged from 50 to 63 days old since swim-up. Spawn dates corresponded to rising pool elevations of Lake Texoma and water pulses of tributaries.

  19. Environmental risk assessment of compost prepared from salvinia, egeria densa, and alligator weed.

    PubMed

    Dorahy, C G; Pirie, A D; McMaster, I; Muirhead, L; Pengelly, P; Chan, K Y; Jackson, M; Barchia, I M

    2009-01-01

    Approximately 70,000 m(3) of salvinia (Salvinia molesta) was removed from the Hawkesbury-Nepean River, New South Wales (NSW), Australia, during 2004. This study assessed the risks associated with applying compost prepared from aquatic weeds (AWC) to land, namely, survival and spread of aquatic and terrestrial weeds, eutrophication of waterways, accumulation of heavy metals and phytotoxicity. The results demonstrate composting is an effective method of reducing the viability of aquatic and terrestrial weeds. However, mortality of alligator weed (Alternanthera philoxeroides), which was used as an indicator plant, was significantly (P < 0.001) correlated with the temperature within the windrows and the length of time the material was subjected to composting. Conditions within the central core of the windrow were sufficient to kill the alligator weed, although not all of the aquatic weed material was exposed to the windrows' central core. This resulted in alligator weed continuing to grow at the base of the windrow. To reduce the risk of weeds surviving and spreading in aquatic and terrestrial environments it is suggested compost windrows should be located on an appropriate hard pad to enable complete mixing of the material and ensure all material is exposed to temperatures >55 degrees C for greater than three consecutive days. The likelihood of other risks associated with the AWC was low. If composting is selected as the preferred method for managing organic material harvested from waterways, then ongoing monitoring and evaluation is required to validate the composting process and ensure consumer confidence in the final product.

  20. Do egg-laying crocodilian (Alligator mississippiensis) archosaurs form medullary bone?

    PubMed

    Schweitzer, M H; Elsey, R M; Dacke, C G; Horner, J R; Lamm, E-T

    2007-04-01

    It is beyond question that Mesozoic dinosaurs, like Aves and Crocodylia, are archosaurs. However, within the archosaurian clade, the origin and distribution of some major features are less clear, particularly with respect to reproductive physiology. Medullary bone, a highly mineralized, bony reproductive tissue present in the endosteal cavities of all extant egg-laying birds thus far examined, has recently been reported in Tyrannosaurus rex. Its presence or absence in extant crocodilians, therefore, may shed light on the timing of its evolutionary appearance. If medullary bone is present in all three taxa, it arose before the three lineages diverged. However, if medullary bone arose after this divergence, it may be present in both extinct dinosaurs and birds, or in birds only. If present in extinct dinosaurs and birds, but not crocodilians, it would indicate that it arose in the common ancestor of this clade, thus adding support to the closer phylogenetic relationship of dinosaurs and birds relative to crocodilians. Thus, the question of whether the crocodilian Alligator mississippiensis forms medullary bone during the production of eggs has important evolutionary significance. Our examination of long bones from several alligators (two alligators with eggs in the oviducts, one that had produced eggs in the past but was not currently in reproductive phase, an immature female and an adult male) shows no differences on the endosteal surfaces of the long bones, and no evidence of medullary bone, supporting the hypothesis that medullary bone first evolved in the dinosaur-bird line, after the divergence of crocodilians from this lineage.

  1. Analysis of the landsat remote sensing images of the types of habitats of Yangtze alligators

    NASA Astrophysics Data System (ADS)

    Huang, Zhujian; Lin, Hengzhang; Zhang, Shengkai

    1986-12-01

    The Chinese “Yangtze” alligator is a rare reptile that has been listed as an “endangered species” by the United Nations, so its preservation has become an urgent task. A study of its habitats through analysis of their Landsat images will provide a scientific basis for the government departments concerned to select the best locations for its breeding. The Chinese alligator is a subtropical reptile of freshwater rivers, lakes and ponds. Found only in China, it is now distributed only in the border region between the three provinces of Anhui, Zhejiang and Jiangsu. On the basis of previous investigations by Chinese scientists, and from an analysis and interpretation of their Landsat images, we made a special study, review, and classification of the natural environment of the alligator’s present habitats (and the modern changes in the natural background of these hatitats) so that the government departments concerned with the preservation of the reptiles may have a scientific basis for determining the best locations for the breeding and propagation of the alligator.

  2. Biosorption of As(V) onto dried alligator weed root: role of metal (hydro) oxides.

    PubMed

    Chen, Jian; Tao, Weihua; Sun, Cheng

    2016-01-01

    The present work investigates the adsorption of As(V) onto the dried powder of alligator weed root as bio-sorbent, using acid pre-treated alligator weed root powder as the reference. The isotherm study suggested there is a favorable As(V) adsorption happened on the AWR surface. The batch adsorption experimental results indicated that the ionic strength has little impact on the adsorption, while the solution pH has a significant effect on the adsorption with apparent inhibition appearing in both extreme acidic and alkaline pH region. In addition, the properties of the biosorbent were characterized by various techniques including SEM-EDS, FT-IR, and ICP detection. The analysis results suggested that the metals including Mn, Fe, and Al enrich over the alligator weed root surface in the morphology of metal (hydro) oxide. Based on the nature of the biosorbent and As(V) besides the adsorption performance, the metal (hydro) oxides over biosorbent surface is suggested as the essential role to drive the adsorption. With the metal (hydro) oxides denuded in the pre-treatment, the biosorbent loses its adsorption capability for As(V) totally.

  3. Variation in Nest Temperatures of the American Alligator Found on the Kennedy Space Center Merritt Island National Wildlife Refuge

    NASA Technical Reports Server (NTRS)

    Lowers, Russell; Guillette, Louis J.; Weiss, Stephanie

    2016-01-01

    Information on nest temperatures of the American Alligator (Alligator mississippiensis) constructed in the wild is limited. Nesting temperatures during a critical thermal sensitive period determine the sex of alligators and are therefore critical in establishing the sex biases in recruitment efforts of alligators within a given community. Nest components, varying environmental conditions, and global warming could have a significant impact on nest temperatures, thus affecting future generations of a given population. One hundred and seventy four programmable thermistors were inserted into fifty eight nests from 2010 through 2015 nesting cycles. Three thermistors were placed inside each nest cavity (one on top of the eggs, one in the middle of the eggs, and one at the bottom of the clutch of the eggs) to collect temperature profiles in the incubation chamber and throughout the entire incubation period. One thermistor was also placed near or above these nests to obtain an ambient air temperature profile. Once retrieved, data from these thermistors were downloaded to examine temperature profiles throughout the incubation period as well as during the period of sexual determination. These data would help establish survival rates related to nest temperature and predict sex ratio of recruited neonates at the Kennedy Space Center. Over three million temperatures have been recorded since 2010 for the alligator thermistor study giving us insight to the recruitment efforts found here. Precipitation was the largest influence on nesting temperatures outside of daily photoperiod, with immediate changes of up to eight degrees Celsius.

  4. Hepatic and renal trace element concentrations in American alligators (Alligator mississippiensis) following chronic dietary exposure to coal fly ash contaminated prey.

    PubMed

    Tuberville, Tracey D; Scott, David E; Metts, Brian S; Finger, John W; Hamilton, Matthew T

    2016-07-01

    Little is known about the propensity of crocodilians to bioaccumulate trace elements as a result of chronic dietary exposure. We exposed 36 juvenile alligators (Alligator mississippiensis) to one of four dietary treatments that varied in the relative frequency of meals containing prey from coal combustion waste (CCW)-contaminated habitats vs. prey from uncontaminated sites, and evaluated tissue residues and growth rates after 12 mo and 25 mo of exposure. Hepatic and renal concentrations of arsenic (As), cadmium (Cd) and selenium (Se) varied significantly among dietary treatment groups in a dose-dependent manner and were higher in kidneys than in livers. Exposure period did not affect Se or As levels but Cd levels were significantly higher after 25 mo than 12 mo of exposure. Kidney As and Se levels were negatively correlated with body size but neither growth rates nor body condition varied significantly among dietary treatment groups. Our study is among the first to experimentally examine bioaccumulation of trace element contaminants in crocodilians as a result of chronic dietary exposure. A combination of field surveys and laboratory experiments will be required to understand the effects of different exposure scenarios on tissue residues, and ultimately link these concentrations with effects on individual health. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. The fine structure and elemental analysis of keratinized epithelium of the filiform papillae analysis on the dorsal tongue in the American alligator (Alligator mississippiensis).

    PubMed

    Shimada, K; Sato, I; Yokoi, A; Kitagawa, T; Tezuka, M; Ishii, T

    1990-03-01

    The filiform papillae of subadult alligator (120 cm-260 cm total length) tongues are examined by scanning electron microscopy and electron microprobe analysis. The filiform papillae form cone-like structures and are observed over the entire dorsal surface of a relatively long tongue with a round tip. The filiform papillae are composed of four layers; outer, upper intermediate, lower intermediate, and basal layer. The keratinized epithelial cells are analysed by the sulphur (S), and nitrogen (N) content levels. The S content is higher than that of N. In the anterior side of the filiform papillae, this content is lower than that in the posteriors. The S content is highest of all at about 2 microns in depth from the surface. These results suggest that the use of S concentration measurements may serve to be an effective tool for a simple, offhand evaluation of keratinization.

  6. Plasma steroid concentrations and male phallus size in juvenile alligators from seven Florida lakes

    USGS Publications Warehouse

    Guillette, L.J.; Woodward, A.R.; Crain, D.A.; Pickford, D.B.; Rooney, A.A.; Percival, H.F.

    1999-01-01

    Neonatal and juvenile alligators from contaminated Lake Apopka in central Florida exhibit abnormal plasma sex steroid concentrations as well as morphological abnormalities of the gonad and phallus. This study addresses whether similar abnormalities occur in juvenile alligators inhabiting six other lakes in Florida. For analysis, animals were partitioned into two subsets, animals 40-79 cm total length (1-3 years old) and juveniles 80-130 cm total length (3-7 years old). Plasma testosterone (T) concentrations were lower in small males from lakes Apopka, Griffin, and Jessup than from Lake Woodruff National Wildlife Refuge (NWR). Similar differences were observed in the larger juveniles, with males from lakes Jessup, Apopka, and Okeechobee having lower plasma T concentrations than Lake Woodruff males. Plasma estradiol-17?? (E2) concentrations were significantly elevated in larger juvenile males from Lake Apopka compared to Lake Woodruff NWR. When compared to small juvenile females from Lake Woodruff NWR, females from lakes Griffin, Apopka, Orange, and Okeechobee had elevated plasma E2 concentrations. Phallus size was significantly smaller in males from lakes Griffin and Apopka when compared to males from Lake Woodruff NWR. An association existed between body size and phallus size on all lakes except Lake Apopka and between phallus size and plasma T concentration on all lakes except lakes Apopka and Orange. Multiple regression analysis, with body size and plasma T concentration as independent covariables, explained the majority of the variation in phallus size on all lakes. These data suggest that the differences in sex steroids and phallus size observed in alligators from Lake Apopka are not limited to that lake, nor to one with a history of a major pesticide spill. Further work examining the relationship of sex steroids and phallus size with specific biotic and abiotic factors, such as antiandrogenic or estrogenic contaminants, is needed.

  7. Physiological response of alligator gar juveniles (Atractosteus spatula) exposed to sub-lethal doses of pollutants.

    PubMed

    González, Carlos Aguilera; Cruz, Julio; Alfaro, Roberto Mendoza

    2015-08-01

    Alligator gar populations have declined because of overfishing, habitat loss and pollution. Over time, the exposure to different pollutants have affected these fishes as a consequence of their high trophic level, bottom-dwelling habits and long life span. In order to evaluate the physiological effects of pollutants on alligator gar, juveniles (6, 12 and 24 months) were exposed to sub-lethal doses of diazinon, β-naphthoflavone (BNF) and 17 β-estradiol (E2) by intraperitoneal injection. After 2 days of exposure, liver samples were taken to determine the activities of acetylcholinesterase, butyrylcholinesterase and carboxylesterase; alkaline and acid phosphatases (ALP and ACP); ethoxyresorufin o-deethylase (EROD); glutathione s-transferase (GST); superoxide dismutase (SOD), and vitellogenin (VTG) concentration. Two additional bioassays consisting on the exposure of compounds through water or food were performed and after 4 and 28 days, respectively, biomarkers were determined. All esterases were inhibited in organisms exposed to diazinon as well as in 6-months gar exposed to E2 and BNF. In contrast, ALP activity increased in gar exposed to diazinon and E2, while ACP activity did not show any variations. No EROD activity was registered after exposure to the different pollutants, despite being one of the most sensitive and common detoxification biomarkers used for fishes. GST activity reduction was detected when gar were exposed to E2 and BNF, while SOD activity increased after exposure to diazinon and E2. Finally, VTG levels were higher in animals exposed to E2 compared to other treatments. Overall, these results suggest that alligator gar juveniles have a low biotransformation metabolism and show that they are especially sensitive to those pollutants affecting the nervous system.

  8. Variation in sex steroids and phallus size in juvenile American alligators (Alligator mississippiensis) collected from 3 sites within the Kissimmee-Everglades drainage in Florida (USA).

    PubMed

    Gunderson, Mark P; Bermudez, Dieldrich S; Bryan, Teresa A; Degala, Satish; Edwards, Thea M; Kools, Stefan A E; Milnes, Matthew R; Woodward, Allan R; Guillette, Louis J

    2004-07-01

    This 3-year study was designed to examine variation in plasma sex steroids, phallus size, and the standard error (S.E.) associated with these endpoints in juvenile alligators collected from 3 sites within the Kissimmee-Everglades drainage (Florida, USA) with varying concentrations of sediment organochlorine contaminants. We hypothesized that decreased plasma sex steroid concentrations and phallus size would be observed in the higher contaminant site when compared to the intermediate and lower contaminant sites. Furthermore, we hypothesized that greater S.E. associated with these endpoints would be observed for the populations from more contaminated sites. We found that differences existed with females from the higher contaminant site exhibiting lower plasma estradiol-17beta (E2) and testosterone (T) concentrations. Males from the higher contaminant site exhibited smaller phallus sizes than males from the intermediate and lower contaminant sites. Smaller phallus size in this case differed from that reported in Lake Apopka male alligators [Gen. Comp. Endocrinol. 116 (1999) 356] in that a significant positive relationship between body size and phallus size existed. No difference among sites was observed in plasma T for males. Lower S.E. was associated with E2 and T concentrations in females from the higher contaminant site and in phallus size in males from the higher contaminant site. This pattern was opposite to what we had hypothesized. We concluded that variation in plasma E2 and T concentrations, phallus size, and the S.E. associated with these endpoints exists among the 3 sites with the patterns matching the patterns of organochlorine contamination, although S.E. patterns were opposite to what was predicted.

  9. In ovo treatment with an estrogen receptor alpha selective agonist causes precocious development of the female reproductive tract of the American alligator (Alligator mississippiensis).

    PubMed

    Doheny, Brenna M; Kohno, Satomi; Parrott, Benjamin B; Guillette, Louis J

    2016-11-01

    The molecular signaling processes involved the differentiation of the Müllerian duct (MD) into the female reproductive tract, or oviduct, in non-mammalian vertebrates are not well understood. Studies in mammals and birds indicate that steroid hormones play a role in this process, as the embryonic MD has been shown to be vulnerable to exogenous estrogens and progestins and environmental endocrine disrupting contaminants. In a previous study, developmental treatment with an estrogen receptor α (ERα) agonist, 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT), induced significant enlargement of the MD in alligator embryos incubated at a male-producing temperature, which was not observed in embryos treated with an estrogen receptor β (ERβ) agonist, 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY 200070), or with 17β-estradiol (E2). In order to understand the role of estrogen signaling in female alligator oviduct development, we incubated eggs at a female-producing temperature and treated them with E2 and these ER selective agonists, PPT and WAY 200070, just prior to the thermosensitive window of sex determination. At stage 27, one stage prior to hatching, PPT induced significant enlargement of the MD with precocious development of secretory glands and connective tissue differentiation similar to characteristics of mature adult oviduct. PPT treatment in ovo increased mRNA expression of ERβ, progesterone receptor, androgen receptor and insulin-like growth factor 1 in MD at stage 27, while expression of ERα was decreased. Neither WAY 200070 nor E2 treatment induced these effects seen in PPT-treated MD. The results of this study provide insight into the critical factors for healthy reproductive system formation in this sentinel species, although further investigation is needed to determine whether the observed phenomena are directly due to selective stimulation of ERα or related to some other aspect of PPT treatment. Copyright © 2016 Elsevier Inc

  10. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina).

    PubMed

    Sirsat, Sarah K G; Sirsat, Tushar S; Price, Edwin R; Dzialowski, Edward M

    2016-04-15

    The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. © 2016. Published by The Company of Biologists Ltd.

  11. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina)

    PubMed Central

    Sirsat, Sarah K. G.; Sirsat, Tushar S.; Price, Edwin R.; Dzialowski, Edward M.

    2016-01-01

    ABSTRACT The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. PMID:26962048

  12. Characterization of microsatellite DNA markers for the alligator snapping turtle, Macrochelys temminckii: Primer note

    USGS Publications Warehouse

    Hackler, J.C.; Van Den Bussche, Ronald A.; Leslie, David M.

    2007-01-01

    Two trinucleotide and seven tetranucleotide microsatellite loci were isolated from an alligator snapping turtle Macrochelys temminckii. To assess the degree of variability in these nine microsatellite loci, we genotyped 174 individuals collected from eight river drainage basins in the southeastern USA. These markers revealed a moderate degree of allelic diversity (six to 16 alleles per locus) and observed heterozygosity (0.166-0.686). These polymorphic microsatellite loci provide powerful tools for population genetic studies for a species that is afforded some level of conservation protection in every state in which it occurs. ?? 2006 The Authors.

  13. Slow isotope turnover rates and low discrimination values in the American alligator: implications for interpretation of ectotherm stable isotope data.

    PubMed

    Rosenblatt, Adam E; Heithaus, Michael R

    2013-01-01

    Stable isotope analysis has become a standard ecological tool for elucidating feeding relationships of organisms and determining food web structure and connectivity. There remain important questions concerning rates at which stable isotope values are incorporated into tissues (turnover rates) and the change in isotope value between a tissue and a food source (discrimination values). These gaps in our understanding necessitate experimental studies to adequately interpret field data. Tissue turnover rates and discrimination values vary among species and have been investigated in a broad array of taxa. However, little attention has been paid to ectothermic top predators in this regard. We quantified the turnover rates and discrimination values for three tissues (scutes, red blood cells, and plasma) in American alligators (Alligator mississippiensis). Plasma turned over faster than scutes or red blood cells, but turnover rates of all three tissues were very slow in comparison to those in endothermic species. Alligator δ(15)N discrimination values were surprisingly low in comparison to those of other top predators and varied between experimental and control alligators. The variability of δ(15)N discrimination values highlights the difficulties in using δ(15)N to assign absolute and possibly even relative trophic levels in field studies. Our results suggest that interpreting stable isotope data based on parameter estimates from other species can be problematic and that large ectothermic tetrapod tissues may be characterized by unique stable isotope dynamics relative to species occupying lower trophic levels and endothermic tetrapods.

  14. The first fossil skull of Alligator sinensis from the Pleistocene, Taiwan, with a paleogeographic implication of the species

    NASA Astrophysics Data System (ADS)

    Hsi-yin, Shan; Yen-nien, Cheng; Xiao-chun, Wu

    2013-06-01

    A nearly complete fossil skull of Alligatoridae from the Pleistocene, Penghu Channel, east of Taiwan, is reported. It can be referred to the most latest clade of Alligatorinae, which includes Alligator sinensis, Alligator mississippiensis and Alligator mefferdi, on the basis of the following features: the splenial is excluded from the mandibular symphysis; the anterior tip of the splenial passes dorsal to the Meckelian groove; and the mandible is gently curved between the fourth alveoli and the mid dentary. It differs from A. mississippiensis and A. mefferdi mainly in the following characters: the breadth between the supratemporal fenestrae is approximately equal to the interorbital width, the snout is about half the length of the skull; and the anterior part of the snout is subtriangular in dorsal view. These features suggest that the Penghu alligator is most probably referable to A. sinensis. This is the only fossil skull of A. sinensis known. The discovery of the skull in Penghu Channel not only provides the first solid fossil evidence to indicate that the geological distribution of A. sinensis extended farther southeast than the historical/archeological range of the species but also adds new information on the biodiversity of the Penghu fauna.

  15. Urinary iodine and stable isotope analysis to examine habitat influences on thyroid hormones among coastal dwelling American alligators.

    PubMed

    Boggs, Ashley S P; Hamlin, Heather J; Nifong, James C; Kassim, Brittany L; Lowers, Russell H; Galligan, Thomas M; Long, Stephen E; Guillette, Louis J

    2016-01-15

    The American alligator, generally a freshwater species, is known to forage in marine environments despite the lack of a salt secreting gland found in other crocodylids. Estuarine and marine foraging could lead to increased dietary uptake of iodine, a nutrient necessary for the production of thyroid hormones. To explore the influence of dietary iodine on thyroid hormone health of coastal dwelling alligators, we described the seasonal plasma thyroxine and triiodothyronine concentrations measured by radioimmunoassay and urinary iodine (UI) concentrations measured by inductively coupled plasma mass spectrometry. We also analyzed long-term dietary patterns through stable isotope analysis of scute tissue. Snout-to-vent length (SVL) was a significant factor among UI and stable isotope analyses. Large adult males greater than 135cm SVL had the highest UI concentrations but did not display seasonality of thyroid hormones. Alligators under 135 SVL exhibited seasonality in thyroid hormones and a positive relationship between UI and triiodothyronine concentrations. Isotopic signatures provided supporting evidence that large males predominantly feed on marine/estuarine prey whereas females showed reliance on freshwater/terrestrial prey supplemented by marine/estuarine prey. UI measurement provided immediate information that correlated to thyroid hormone concentrations whereas stable isotope analysis described long-term dietary patterns. Both techniques demonstrate that adult alligators in coastal environments are utilizing estuarine/marine habitats, which could alter thyroid hormone physiology. Published by Elsevier Inc.

  16. Ligation of the left aorta in alligators affects acid-base balance: a role for the R→L shunt.

    PubMed

    Gardner, Manuela N; Sterba-Boatwright, Blair; Jones, David R

    2011-09-15

    This study investigated the effects of preventing bulk flow from the right ventricle to the body via the left aorta (LAo; right to left shunt, R→L) on acid-base status in alligators following feeding, during long-term fasting and a cold temperature exposure. Post-feeding pHv and [Formula: see text] were not significantly different between S and C. Post-feeding pHv increased in both groups of alligators, but not significantly. During fasting, all acid-base variables were similar between the two groups of alligators. A 10 °C reduction in environmental temperature resulted in a significant difference in pHv and HCO3- between S and C. Both pHv and HCO3- were significantly higher in C animals. PV(CO2) significantly decreased in both groups during the cold exposure. Preventing the R→L shunt via the LAo had significant effects on acid-base balance in alligators indicating incomplete compensation for its loss and a role for the LAo in metabolic homeostasis. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Nuclear β-catenin localization supports homology of feathers, avian scutate scales, and alligator scales in early development.

    PubMed

    Musser, Jacob M; Wagner, Günter P; Prum, Richard O

    2015-01-01

    Feathers are an evolutionary novelty found in all extant birds. Despite recent progress investigating feather development and a revolution in dinosaur paleontology, the relationship of feathers to other amniote skin appendages, particularly reptile scales, remains unclear. Disagreement arises primarily from the observation that feathers and avian scutate scales exhibit an anatomical placode-defined as an epidermal thickening-in early development, whereas alligator and other avian scales do not. To investigate the homology of feathers and archosaur scales we examined patterns of nuclear β-catenin localization during early development of feathers and different bird and alligator scales. In birds, nuclear β-catenin is first localized to the feather placode, and then exhibits a dynamic pattern of localization in both epidermis and dermis of the feather bud. We found that asymmetric avian scutate scales and alligator scales share similar patterns of nuclear β-catenin localization with feathers. This supports the hypothesis that feathers, scutate scales, and alligator scales are homologous during early developmental stages, and are derived from early developmental stages of an asymmetric scale present in the archosaur ancestor. Furthermore, given that the earliest stage of β-catenin localization in feathers and archosaur scales is also found in placodes of several mammalian skin appendages, including hair and mammary glands, we hypothesize that a common skin appendage placode originated in the common ancestor of all amniotes. We suggest a skin placode should not be defined by anatomical features, but as a local, organized molecular signaling center from which an epidermal appendage develops.

  18. In vivo bone strain and finite element modeling of the mandible of Alligator mississippiensis

    PubMed Central

    Porro, Laura B; Metzger, Keith A; Iriarte-Diaz, Jose; Ross, Callum F

    2013-01-01

    Forces experienced during feeding are thought to strongly influence the morphology of the vertebrate mandible; in vivo strain data are the most direct evidence for deformation of the mandible induced by these loading regimes. Although many studies have documented bone strains in the mammalian mandible, no information is available on strain magnitudes, orientations or patterns in the sauropsid lower jaw during feeding. Furthermore, strain gage experiments record the mechanical response of bone at a few locations, not across the entire mandible. In this paper, we present bone strain data recorded at various sites on the lower jaw of Alligator mississippiensis during in vivo feeding experiments. These data are used to understand how changes in loading regime associated with changes in bite location are related to changes in strain regime on the working and balancing sides of the mandible. Our results suggest that the working side mandible is bent dorsoventrally and twisted about its long-axis during biting, and the balancing side experiences primarily dorsoventral bending. Strain orientations are more variable on the working side than on the balancing side with changes in bite point and between experiments; the balancing side exhibits higher strain magnitudes. In the second part of this paper, we use principal strain orientations and magnitudes recorded in vivo to evaluate a finite element model of the alligator mandible. Our comparison demonstrates that strain orientations and mandibular deformation predicted by the model closely match in vivo results; however, absolute strain magnitudes are lower in the finite element model. PMID:23855772

  19. Spermiogenesis in the imbricate alligator lizard, Barisia imbricata (Reptilia, Squamata, Anguidae).

    PubMed

    Gribbins, Kevin M; Rheubert, Justin L; Touzinsky, Katherine; Hanover, Jessica; Matchett, Caroline L; Granados-González, Gisela; Hernández-Gallegos, Oswaldo

    2013-06-01

    Although the events of spermiogenesis are commonly studied in amniotes, the amount of research available for Squamata is lacking. Many studies have described the morphological characteristics of mature spermatozoa in squamates, but few detail the ultrastructural changes that occur during spermiogenesis. This study's purpose is to gain a better understanding of the subcellular events of spermatid development within the Imbricate Alligator Lizard, Barisia imbricata. The morphological data presented here represent the first complete ultrastructural study of spermiogenesis within the family Anguidae. Samples of testes from four specimens collected on the northwest side of the Nevado de Toluca, México, were prepared using standard techniques for transmission electron microscopy. Many of the ultrastructural changes occurring during spermiogenesis within B. imbricata are similar to that of other squamates (i.e., early acrosome formation, chromatin condensation, flagella formation, annulus present, and a prominent manchette). However, there are a few unique characteristics within B. imbricata spermatids that to date have not been described during spermiogenesis in other squamates. For example, penetration of the acrosomal granule into the subacrosomal space to form the basal plate of the perforatorium during round spermatid development, the clover-shaped morphology of the developing nuclear fossa of the flagellum, and the bulbous shape to the perforatorium are all unique to the Imbricate Alligator Lizard. These anatomical character differences may be valuable nontraditional data that along with more traditional matrices (such as DNA sequences and gross morphological data) may help elucidate phylogenetic relationships, which are historically considered controversial within Squamata.

  20. Vegetative propagation capacity of invasive alligator weed through small stolon fragments under different treatments.

    PubMed

    Peng, Xuemei; Li, Haiyan; Yang, Yunfei; Zhi, Heng; Li, Chengcheng; Guo, Jian

    2017-03-06

    The ability to propagate via small diaspores is crucial for the invasion of a clone plant that does not reproduce sexually in its introduced range. We investigated the effects of node and internode adjacent mode, fragment type, burial orientation and position of the node in relation to the soil surface on the sprouting and growth of alligator weed (Alternanthera philoxeroides (Martius) Griseb.). All the factors had effects and interaction effects on the sprouting rate and growth. As a whole fragment in all treatments, the fragments with basal node buried upward on the soil surface, exhibited the best above-ground growth and root growth. The one-node fragment with basal node buried downward above the soil surface and upward under the soil surface significantly decreased the above-ground growth and root growth compared to that of the two-node fragment. Therefore, the one-node fragments were more affected by environmental conditions than the two-node fragments. The results indicated that reducing the number of nodes of a fragment and burying the node under the soil or orienting it downward above the soil surface could be applied to control the invasion of alligator weed.

  1. Scaling the Feeding Mechanism of Captive Alligator mississippiensis from Hatchling to Juvenile

    PubMed Central

    Kerfoot, James R.; Fern, Micah P.; Elsey, Ruth M.

    2014-01-01

    Small changes in size can lead to potential performance consequences and may influence an organism’s ability to utilize resources in its environment. As the American alligator (Alligator mississippiensis) transitions between neonate, juvenile and adult habitats (ontogenetic niche shifts), there are inevitably dynamic changes in their feeding performance. This study sought to investigate the scaling of the feeding mechanism and its performance from hatchling to juvenile size classes in A. mississippiensis. Feeding events were recorded during March 2011 at Rockefeller Wildlife Refuge (Grand Chenier, Louisiana). Thirty-six captive individuals were randomly sampled, ranging from 30.5 cm to 91.5 cm total length, and feeding events were recorded using a high speed camera at a rate of 300 fps. Results indicated that many linear, angular and timing kinematic variables scale allometrically with cranium length; whereas maximum gape velocity and duration of feeding bout do not scale with cranium length and remain constant between these size classes. Although it has been shown that there is an isometric relationship between cranial elements and body size in A. mississippiensis, this relationship is not transferred to linear and timing variables of prey-capture events. These allometric relationships echo other investigations of scaling relationships such as bite-force production and terrestrial locomotion. PMID:25390506

  2. Three-dimensional skeletal kinematics of the shoulder girdle and forelimb in walking Alligator

    PubMed Central

    Baier, David B; Gatesy, Stephen M

    2013-01-01

    Crocodylians occupy a key phylogenetic position for investigations of archosaur locomotor evolution. Compared to the well-studied hindlimb, relatively little is known about the skeletal movements and mechanics of the forelimb. In this study, we employed manual markerless XROMM (X-ray Reconstruction Of Moving Morphology) to measure detailed 3-D kinematics of the shoulder girdle and forelimb bones of American alligators (Alligator mississippiensis) walking on a treadmill. Digital models of the interclavicle, scapulocoracoid, humerus, radius and ulna were created using a 3-D laser scanner. Models were articulated and aligned to simultaneously recorded frames of fluoroscopic and standard light video to reconstruct and measure joint motion. Joint coordinate systems were established for the coracosternal, glenohumeral and elbow joints. Our analysis revealed that the limb joints only account for about half of fore/aft limb excursion; the remaining excursion results from shoulder girdle movements and lateral bending of the vertebral column. Considerable motion of each scapulocoracoid relative to the vertebral column is consistent with coracosternal mobility. The hemisellar design of the glenohumeral joint permits some additional translation, or sliding in the fore-aft plane, but this movement does not have much of an effect on the distal excursion of the bone. PMID:24102540

  3. Trigeminal nerve morphology in Alligator mississippiensis and its significance for crocodyliform facial sensation and evolution.

    PubMed

    George, Ian D; Holliday, Casey M

    2013-04-01

    Modern crocodylians possess a derived sense of face touch, in which numerous trigeminal nerve-innervated dome pressure receptors speckle the face and mandible and sense mechanical stimuli. However, the morphological features of this system are not well known, and it remains unclear how the trigeminal system changes during ontogeny and how it scales with other cranial structures. Finally, when this system evolved within crocodyliforms remains a mystery. Thus, new morphological insights into the trigeminal system of extant crocodylians may offer new paleontological tools to investigate this evolutionary transformation. A cross-sectional study integrating histological, morphometric, and 3D imaging analyses was conducted to identify patterns in cranial nervous and bony structures of Alligator mississippiensis. Nine individuals from a broad size range were CT-scanned followed by histomorphometric sampling of mandibular and maxillary nerve divisions of the trigeminal nerve. Endocast volume, trigeminal fossa volume, and maxillomandibular foramen size were compared with axon counts from proximal and distal regions of the trigeminal nerves to identify scaling properties of the structures. The trigeminal fossa has a significant positive correlation with skull length and endocast volume. We also found that axon density is greater in smaller alligators and total axon count has a significant negative correlation with skull size. Six additional extant and fossil crocodyliforms were included in a supplementary scaling analysis, which found that size was not an accurate predictor of trigeminal anatomy. This suggests that phylogeny or somatosensory adaptations may be responsible for the variation in trigeminal ganglion and nerve size in crocodyliforms.

  4. Vegetative propagation capacity of invasive alligator weed through small stolon fragments under different treatments

    PubMed Central

    Peng, Xuemei; Li, Haiyan; Yang, Yunfei; Zhi, Heng; Li, Chengcheng; Guo, Jian

    2017-01-01

    The ability to propagate via small diaspores is crucial for the invasion of a clone plant that does not reproduce sexually in its introduced range. We investigated the effects of node and internode adjacent mode, fragment type, burial orientation and position of the node in relation to the soil surface on the sprouting and growth of alligator weed (Alternanthera philoxeroides (Martius) Griseb.). All the factors had effects and interaction effects on the sprouting rate and growth. As a whole fragment in all treatments, the fragments with basal node buried upward on the soil surface, exhibited the best above-ground growth and root growth. The one-node fragment with basal node buried downward above the soil surface and upward under the soil surface significantly decreased the above-ground growth and root growth compared to that of the two-node fragment. Therefore, the one-node fragments were more affected by environmental conditions than the two-node fragments. The results indicated that reducing the number of nodes of a fragment and burying the node under the soil or orienting it downward above the soil surface could be applied to control the invasion of alligator weed. PMID:28262788

  5. Calcium binding protein expression in the optic tectum of Alligator during development.

    PubMed

    Ruan, Y-W; So, K-F; Pritz, M B

    2013-12-01

    The onset and distribution of the calcium binding proteins, calretinin, calbindin, and parvalbumin, were examined in the optic tectum of Alligator mississipiensis embryos between Stages 18 and 26-28. The immunoreactivity of each calcium binding protein correlated well with the results from the Western blot experiments. In terms of onset and distribution, calretinin expressison was the most widespread of the three calcium binding proteins that were examined, and was also the earliest to be visualized. Calbindin expression occurred next, whereas parvalbumin expression was the most limited and appeared last. For small calretinin (+) neurons, the pattern of immunoreactivity during development was from inside to outside, whereas for the larger cells, it was from outside to inside. For calbindin immunoreactive cells in the superficial zone, the pattern was from outside to inside. The distribution of the parvalbumin immunopositive neurons did not change significantly over the time period examined. Similar data on other amniotes is limited. However, the pattern in Alligator shares some similarities with kittens in regards to the distribution of calbindin and parvalbumin in the developing superior colliculus.

  6. Radionuclides and metals in freshwater mussels of the upper South Alligator River, Australia.

    PubMed

    Ryan, Bruce; Bollhöfer, Andreas; Martin, Paul

    2008-03-01

    During an inspection of the old Rockhole Mine area in Kakadu National Park in 1999, it was found that a small amount of tailings from the former South Alligator uranium (U) mill had been uncovered by wet season rain and road works. Samples of sediment, water and freshwater mussels, Velesunio angasi, were collected from the South Alligator River, near and at the confluence of Rockhole Mine Creek, and adjacent to the exposed tailings. The 228Ra/226Ra activity ratios in sediments and mussel tissue indicate a small influence from the tailings and from Rockhole Mine adit water on 226Ra concentrations. The uptake of 226Ra in mussels does not correlate with other alkaline-earth metals. Mussel U concentrations are higher immediately downstream of Rockhole Mine Creek, but there is no noticeable increase in the immediate vicinity of the tailings area. A hypothetical ingestion of 2 kg of mussels from the sites was used to estimate the committed effective dose for a 10-year-old child resulting in a figure of 0.23 mSv per annum, of this total dose, 69% is attributed to 210Po. Only 0.03 mSv per annum can be directly linked to impacts of the tailings.

  7. Quantification of intraskeletal histovariability in Alligator mississippiensis and implications for vertebrate osteohistology

    PubMed Central

    Horner, John R.; Farlow, James O.

    2014-01-01

    Bone microanalyses of extant vertebrates provide a necessary framework from which to form hypotheses regarding the growth and skeletochronology of extinct taxa. Here, we describe the bone microstructure and quantify the histovariability of appendicular elements and osteoderms from three juvenile American alligators (Alligator mississippiensis) to assess growth mark and tissue organization within and amongst individuals, with the intention of validating paleohistological interpretations. Results confirm previous observations that lamellar and parallel fibered tissue organization are typical of crocodylians, and also that crocodylians are capable of forming woven tissue for brief periods. Tissue organization and growth mark count varies across individual skeletal elements and reveal that the femur, tibia, and humerus had the highest annual apposition rates in each individual. Cyclical growth mark count also varies intraskeletally, but data suggest these inconsistencies are due to differing medullary cavity expansion rates. There was no appreciable difference in either diaphyseal circumference or cyclical growth mark circumferences between left and right element pairs from an individual if diaphyses were sampled from roughly the same location. The considerable intraskeletal data obtained here provide validation for long-held paleohistology assumptions, but because medullary expansion, cyclical growth mark formation, and variable intraskeletal growth rates are skeletal features found in tetrapod taxa living or extinct, the validations presented herein should be considered during any tetrapod bone microanalysis. PMID:24949239

  8. Physiological variability in yearling alligators: clutch differences at rest and during activity.

    PubMed

    Bagatto, B; Crossley, D A; Altimiras, J; Elsey, R M; Hicks, J W

    2012-05-01

    The adult phenotype of an organism is the result of its genotype, the environment, and the interaction between the two. Assessing the relative contribution of these factors to the final adult phenotype continues to occupy researchers. Studies have shown clutch effects early in development but few have investigated the persistence of clutch effects on a longer time scale. Five clutches of American alligators were reared for 1 year in a common environment then assessed for the presence of clutch effects as they related to morphological and physiological characteristics. After 1 year, significant clutch effects were evident in all size related variables despite open access to food. Additionally, lung and liver masses remained different between clutches after animal mass was taken into account. Although clutch had no effect on resting heart rate, it significantly contributed to mean arterial pressure. During swimming and exhaustive exercise, the resulting respiratory and metabolic acidoses were strongly dependent on clutch. Therefore, while the environment can have significant influences on the American alligator from hatching to death, the measureable contribution of genetics to the morphology and physiology of the organism remains evident, even after 1 year of common rearing conditions. It behooves researchers to acknowledge and control for clutch effects when designing experiments. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Potential impact of Dare County landfills on Alligator River National Wildlife Refuge

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.; Augspurger, T.

    2005-01-01

    Runoff of leachate from East Lake and Dare County Construction and Demolition Debris landfills has the potential to impact wildlife resources at Alligator River National Wildlife Refuge, Dare and Hyde Counties, North Carolina. Sediment quality of samples collected in August 2000 at 14 locations down-gradient from the landfills was assessed by measuring metal and organic contaminants in the sediments, chronic toxicity of solid-phase sediment (28-d static-renewal exposures; survival and growth as test endpoints) and acute toxicity of sediment porewater (96-h static exposures) to Hyalella azteca (Crustacea: Amphipoda). In addition, contaminant bioaccumulation from 4 sediments was determined using 28-d exposures of Lumbriculus variegatus (freshwater oligochaete). Although survival was not impaired, length of H. azteca was significantly reduced in sediments from 5 locations. Pore water from 4 locations was acutely toxic to H. azteca. Metals and a few polycyclic aromatic hydrocarbons (PAHs) were bioaccumulated by L. variegatus from the sediments. Several metals and PAHs exceeded sediment quality guidelines, and metals in porewater from several sites exceeded water quality criteria for the protection of aquatic wildlife. Runoff of leachate from the landfills has reduced sediment quality and has the potential to adversely affect wildlife resources at Alligator River National Wildlife Refuge.

  10. Gonadal steroidogenesis in vitro from juvenile alligators obtained from contaminated or control lakes.

    PubMed Central

    Guillette, L J; Gross, T S; Gross, D A; Rooney, A A; Percival, H F

    1995-01-01

    The ubiquitous distribution of many contaminants and the nonlethal, multigenerational effects of such contaminants on reproductive, endocrine, and immune systems have led to concerns that wildlife worldwide are affected. Although the causal agents and effects are known for some species, the underlying physiological mechanisms associated with contaminant-induced reproductive modifications are still poorly understood and require extensive research. We describe a study examining the steroidogenic activity of gonads removed from juvenile alligators (Alligator mississippiensis) obtained from contaminated or control lakes in central Florida. Synthesis of estradiol-17 beta (E2) was significantly different when ovaries from the contaminated and control lakes were compared in vitro. Additionally, testes from males obtained from the contaminated lake. Lake Apopka, synthesized significantly higher concentrations of E2 when compared to testes obtained from control males. In contrast, testosterone (T) synthesis from all testes examined in this study displayed a normal pattern and produced concentrations greater than that observed from ovaries obtained from either lake. Interestingly, the pattern of gonadal steroidogenesis differs from previously reported plasma concentrations of these hormones obtained from the same individuals. We suggest that the differences between the in vivo and in vitro patterns are due to modifications in the hepatic degradation of plasma sex steroid hormones. PMID:7556021

  11. Abnormal bone composition in female juvenile American alligators from a pesticide-polluted lake (Lake Apopka, Florida).

    PubMed

    Lind, P Monica; Milnes, Matthew R; Lundberg, Rebecca; Bermudez, Dieldrich; Orberg, Jan A; Guillette, Louis J

    2004-03-01

    Reproductive disorders have been found in pesticide-exposed alligators living in Lake Apopka, Florida (USA). These disorders have been hypothesized to be caused by exposure to endocrine- disruptive estrogen-like contaminants. The aim of this study was to expand our analysis beyond previous studies by investigating whether bone tissue, known to be affected by sex steroid hormones, is a potential target of endocrine disruptors. Long bones from 16 juvenile female alligators from Lake Apopka (pesticide-contaminated lake) and Lake Woodruff (control lake) were evaluated by peripheral quantitative computed tomography. We observed significant differences in bone composition, with female alligators from the contaminated lake having greater trabecular bone mineral density (BMD), total BMD, and trabecular mineral content compared with females from the control lake (p < 0.05). Increased trabecular and total BMD measurements suggest that juvenile female alligators from Lake Apopka were exposed to contaminants that created an internal environment more estrogenic than that normally observed. This estrogenic environment could be caused by both natural and anthropogenic compounds. Effects on BMD indicate interference with bone homeostasis. We hypothesize that contaminants present in the lake inhibit the natural and continuous resorption of bone tissue, resulting in increased bone mass. Although this is the only study performed to date examining effects of environmental estrogenic compounds on alligator bones, it supports previous laboratory-based studies in rodents. Further, this study is important in demonstrating that the alterations in morphology and physiology induced in free-ranging individuals living in environments contaminated with endocrine-active compounds are not limited to a few systems or tissues; rather, effects can be observed in many tissues affected by these hormones.

  12. Induction time course of cytochromes P450 by phenobarbital and 3-methylcholanthrene pretreatment in liver microsomes of Alligator mississippiensis.

    PubMed

    Ertl, R P; Stegeman, J J; Winston, G W

    1998-05-01

    Alligator mississippiensis has at least two classes of inducible hepatic microsomal cytochromes P450 (CYP): (1) those induced by 3-methylcholanthrene (3MC), and (2) those induced by phenobarbital (PB). The rates of induction by these xenobiotic compounds are significantly slower than those reported for mammals. Carbon monoxide binding, western blots, and enzymatic activity measurements indicated that at least 48-72 hr are required to reach full induction. A methoxy-, ethoxy-, pentoxy, and benzyloxyphenoxazone (resorufin) O-dealkylation (MROD, EROD, PROD, and BROD) profile was indicative of substrate selectivity typical of 3MC- and PB-induced P450s. MROD and BROD showed the greatest ability to discriminate between alligator hepatic microsomes induced by 3MC and PB, respectively. This is in contrast to mammals, in which EROD is a biomarker of polycyclic aromatic hydrocarbon exposure because of its ability to discriminate the induction of CYP 1A. In a similar manner, PROD is a highly preferred activity of CYP 2B in mammals; thus, it is used to indicate CYP 2B induction. The induction of P450 by PB is a general phenomenon in mammals and birds. To the best of our knowledge, this is the first report demonstrating PB induction of P450 activities typical of the mammalian CYP 2 family isoforms in alligator or any reptilian liver. The importance of this finding to the evolution of CYP 2 family regulation by PB is heightened by the fact that induction by this xenobiotic is not common to fish and other lower vertebrates (Ertl RP and Winston GW, Comp Biochem Physiol, in press). Although indicating the presence of CYP 1A- and CYP 2B-like isoforms in alligator, it remains to be established how closely related these alligator P450s are to mammalian isoforms.

  13. Developmental abnormalities of the gonad and abnormal sex hormone concentrations in juvenile alligators from contaminated and control lakes in Florida.

    PubMed Central

    Guillette, L J; Gross, T S; Masson, G R; Matter, J M; Percival, H F; Woodward, A R

    1994-01-01

    The reproductive development of alligators from a contaminated and a control lake in central Florida was examined. Lake Apopka is adjacent to an EPA Superfund site, listed due to an extensive spill of dicofol and DDT or its metabolites. These compounds can act as estrogens. Contaminants in the lake also have been derived from extensive agricultural activities around the lake that continue today and a sewage treatment facility associated with the city of Winter Garden, Florida. We examined the hypothesis that an estrogenic contaminant has caused the current failure in recruitment of alligators on Lake Apopka. Supporting data include the following: At 6 months of age, female alligators from Lake Apopka had plasma estradiol-17 beta concentrations almost two times greater than normal females from the control lake, Lake Woodruff. The Apopka females exhibited abnormal ovarian morphology with large numbers of polyovular follicles and polynuclear oocytes. Male juvenile alligators had significantly depressed plasma testosterone concentrations comparable to levels observed in normal Lake Woodruff females but more than three times lower than normal Lake Woodruff males. Additionally, males from Lake Apopka had poorly organized testes and abnormally small phalli. The differences between lakes and sexes in plasma hormone concentrations of juvenile alligators remain even after stimulation with luteinizing hormone. Our data suggest that the gonads of juveniles from Lake Apopka have been permanently modified in ovo, so that normal steroidogenesis is not possible, and thus normal sexual maturation is unlikely. Images p680-a Figure 1. Figure 2. Figure 3. A Figure 3. B Figure 3. C Figure 4. A Figure 4. B Figure 4. C Figure 4. D Figure 5. A Figure 5. B Figure 5. C PMID:7895709

  14. Study of red-sore disease in alligators. Final report, September 1, 1976-September 3, 1980. [Predisposing factors

    SciTech Connect

    Gorden, R.E.; Esch, G.W.

    1980-01-01

    Necropsies of eight alligators which died following capture within a thermally-altered reservoir demonstrated the presence of the gram negative, pathogenic bacterium Aeromonas hydrophila, in internal tissues. A study designed to demonstrate whether A. hydrophila were capable of causing infection and death of the ecologically threatened alligator and, if so, the mechanism of exposure and infection in natural habitats was undertaken. The pathology and response to infection were also studied. When juvenile alligators were exposed under experimental conditions to increasing concentrations of A. hydrophila in water, by oral inoculation, or by intramuscular injections at 20/sup 0/, 25/sup 0/, 30/sup 0/, and 35/sup 0/C, they developed external lesions. These lesions were likely to become severe and lead to death of the animal at 30 and 35/sup 0/C. Infected animals produced: (a) increased numbers of white blood cells; (b) increased specific antibody titer; and (c) alpha 2 peaks higher than albumen peaks (except at 35/sup 0/C). Biweekly intraperitoneal injections of live, washed A. hydrophila were apparently more effective in the prevention of infection and of external lesions than were the antibiotics Kanamycin and OTH-Puramycin. Topical applications of Neosporin ointment resulted in the healing of severe lesions on confined animals. Alligators which were shown to be exposed to A. hydrophila in their natural habitats showed no external evidence of infection by the bacteria. It is recommended that exposure to conditions of stress, including water temperatures greater than 30/sup 0/C, be kept to a minimum during the capture, transport, and captivity of alligators. (ERB)

  15. Abnormal bone composition in female juvenile American alligators from a pesticide-polluted lake (Lake Apopka, Florida).

    PubMed Central

    Lind, P Monica; Milnes, Matthew R; Lundberg, Rebecca; Bermudez, Dieldrich; Orberg, Jan A; Guillette, Louis J

    2004-01-01

    Reproductive disorders have been found in pesticide-exposed alligators living in Lake Apopka, Florida (USA). These disorders have been hypothesized to be caused by exposure to endocrine- disruptive estrogen-like contaminants. The aim of this study was to expand our analysis beyond previous studies by investigating whether bone tissue, known to be affected by sex steroid hormones, is a potential target of endocrine disruptors. Long bones from 16 juvenile female alligators from Lake Apopka (pesticide-contaminated lake) and Lake Woodruff (control lake) were evaluated by peripheral quantitative computed tomography. We observed significant differences in bone composition, with female alligators from the contaminated lake having greater trabecular bone mineral density (BMD), total BMD, and trabecular mineral content compared with females from the control lake (p < 0.05). Increased trabecular and total BMD measurements suggest that juvenile female alligators from Lake Apopka were exposed to contaminants that created an internal environment more estrogenic than that normally observed. This estrogenic environment could be caused by both natural and anthropogenic compounds. Effects on BMD indicate interference with bone homeostasis. We hypothesize that contaminants present in the lake inhibit the natural and continuous resorption of bone tissue, resulting in increased bone mass. Although this is the only study performed to date examining effects of environmental estrogenic compounds on alligator bones, it supports previous laboratory-based studies in rodents. Further, this study is important in demonstrating that the alterations in morphology and physiology induced in free-ranging individuals living in environments contaminated with endocrine-active compounds are not limited to a few systems or tissues; rather, effects can be observed in many tissues affected by these hormones. PMID:14998753

  16. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  17. THE FUNCTIONAL AND STRUCTURAL OBSERVATIONS OF THE NEONATAL REPRODUCTIVE SYSTEM OF ALLIGATORS EXPOSED IN OVO TO ATRAZINE, 2,4-D, OR ESTRADIOL.

    EPA Science Inventory

    Wild alligators exposed to persistent organochlorine contaminants, municipal waste compounds, and contemporary-use herbicides exhibit reproductive alterations that are thought to be caused by endocrine disruption. This study tests the hypothesis that these alterations, at least i...

  18. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  19. THE FUNCTIONAL AND STRUCTURAL OBSERVATIONS OF THE NEONATAL REPRODUCTIVE SYSTEM OF ALLIGATORS EXPOSED IN OVO TO ATRAZINE, 2,4-D, OR ESTRADIOL.

    EPA Science Inventory

    Wild alligators exposed to persistent organochlorine contaminants, municipal waste compounds, and contemporary-use herbicides exhibit reproductive alterations that are thought to be caused by endocrine disruption. This study tests the hypothesis that these alterations, at least i...

  20. Multilocus phylogeny of alligator lizards (Elgaria, Anguidae): Testing mtDNA introgression as the source of discordant molecular phylogenetic hypotheses.

    PubMed

    Leavitt, Dean H; Marion, Angela B; Hollingsworth, Bradford D; Reeder, Tod W

    2017-05-01

    The increased availability of nuclear DNA sequence data has led to a better appreciation of the role and frequency of introgressive hybridization and subsequent mitochondrial capture in misleading phylogenetic hypotheses based on mtDNA sequence data alone. Relationships among members of the alligator lizard genus Elgaria have been addressed with morphology, allozyme and mtDNA sequence data with discordant results. In this study, we use seven nuclear loci (total of 5.9kb) and ∼3kb of mtDNA to infer the phylogenetic relationships among Elgaria species and test whether the discordance among previous phylogenetic hypotheses is due to introgression and mtDNA capture. While gene tree topologies varied among the different loci, we recovered a well-resolved coalescent-based species tree. Contrary to our expectations, the nDNA-only species tree does not support the sister relationship between E. kingii and E. panamintina inferred from the previous allozyme study. Nevertheless, we found evidence for possible mitochondrial capture in two unexpected situations. The first instance of mtDNA capture involves E. paucicarinata from the Cape Region of Baja California. MtDNA recovered a clade comprising E. paucicarinata and the other two peninsular endemics, while the nDNA-only species tree recovered E. paucicarinata as sister to the continental E. kingii. We hypothesize that this discordance is the result of ancient mitochondrial capture rather than incomplete lineage sorting. Additionally, analyses of nDNA recovered E. panamintina as sister to an E. multicarinata North lineage, whereas the mtDNA gene tree recovers E. panamintina nested within a southern E. multicarinata clade. We hypothesize that this discordance also may be due to mitochondrial capture. Additionally, hybridization between these two lineages may have resulted in geographically limited nuclear introgression. Divergence dating analyses suggest that oviparous Elgaria species diverged within a relatively narrow

  1. A database of radionuclide activity and metal concentrations for the Alligator Rivers Region uranium province.

    PubMed

    Doering, Che; Bollhöfer, Andreas

    2016-10-01

    This paper presents a database of radionuclide activity and metal concentrations for the Alligator Rivers Region (ARR) uranium province in the Australian wet-dry tropics. The database contains 5060 sample records and 57,473 concentration values. The data are for animal, plant, soil, sediment and water samples collected by the Environmental Research Institute of the Supervising Scientist (ERISS) as part of its statutory role to undertake research and monitoring into the impacts of uranium mining on the environment of the ARR. Concentration values are provided in the database for 11 radionuclides ((227)Ac, (40)K, (210)Pb, (210)Po, (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (234)U, (238)U) and 26 metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, S, Sb, Se, Sr, Th, U, V, Zn). Potential uses of the database are discussed.

  2. Guidelines for choosing molecular "alligator clip" binding motifs in electron transport devices

    NASA Astrophysics Data System (ADS)

    Reuter, Matthew G.; Seideman, Tamar; Ratner, Mark A.

    2011-04-01

    We employ a one-electron, tight-binding model of an electrode-molecule-electrode junction to explore the fundamental relationship between adsorption geometry and electron transport, producing exact results (within this model). By varying the chemisorption location (e.g., atop a surface atom or in a hollow site between surface atoms) and the molecule-electrode coupling, we find that the largest currents are realized when the molecule (i) is highly coordinated by the surface and (ii) has favorable overlap with electrode states near the Fermi level. We also show the importance of electrode-induced molecular level shifting for certain adsorption geometries, which can cause molecular levels far from the Fermi level to conduct better than those near the Fermi level. Since all of these factors are greatly influenced by the chemical moiety used to link the molecule to an electrode, these results present a set of guidelines to help choose "alligator clips" for molecular electronic devices.

  3. ALLIGATOR - An apparatus for ion beam assisted deposition with a broad-beam ion source

    NASA Astrophysics Data System (ADS)

    Wituschek, H.; Barth, M.; Ensinger, W.; Frech, G.; Rück, D. M.; Leible, K. D.; Wolf, G. K.

    1992-04-01

    Ion beam assisted deposition is a versatile technique for preparing thin films and coatings for various applications. Up to now a prototype setup for research purposes has been used in our laboratory. Processing of industrial standard workpieces requires a high current ion source with broad beam and high uniformity for homogeneous bombardment. In this contribution a new apparatus for large area samples will be described. It is named ALLIGATOR (German acronym of facility for ion assisted evaporation on transverse movable or rotary targets). In order to have a wide energy range available two ion sources are used. One delivers a beam energy up to 1.3 keV. The other is suitable for energies from 5 keV up to 40 keV. The ``high-energy'' ion source is a multicusp multiaperture source with 180-mA total current and a beam diameter of 280 mm at the target position.

  4. Ontogeny of the Middle-Ear Air-Sinus System in Alligator mississippiensis (Archosauria: Crocodylia)

    PubMed Central

    Dufeau, David L.; Witmer, Lawrence M.

    2015-01-01

    Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic sinuses invading the cranium. These sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph—indeed archosaurian—evolution is characterized by the evolution of various paratympanic air sinuses, the homologies of which are poorly understood due in large part to the fact that individual sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these sinuses primarily to clarify the anatomical relations of the individual sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic sinuses are simply an allometric function of braincase

  5. Functional specialization and ontogenetic scaling of limb anatomy in Alligator mississippiensis.

    PubMed

    Allen, Vivian; Elsey, Ruth M; Jones, Nicola; Wright, Jordon; Hutchinson, John R

    2010-04-01

    Crocodylians exhibit a fascinating diversity of terrestrial gaits and limb motions that remain poorly described and are of great importance to understanding their natural history and evolution. Their musculoskeletal anatomy is pivotal to this diversity and yet only qualitative studies of muscle-tendon unit anatomy exist. The relative masses and internal architecture (fascicle lengths and physiological cross-sectional areas) of muscles of the pectoral and pelvic limbs of American alligators (Alligator mississippiensis Daudin 1801) were recorded for an ontogenetic series of wild specimens (n = 15, body masses from 0.5 to 60 kg). The data were analysed by reduced major axis regression to determine scaling relationships with body mass. Physiological cross-sectional areas and therefore muscle force-generating capacity were found to be greater in the extensor (anti-gravity) muscles of the pelvic limb than in the pectoral limb, reflecting how crocodylians differ from mammals in having greater loading of the hindlimbs than the forelimbs. Muscle masses and architecture were generally found to scale isometrically with body mass, suggesting an ontogenetic decrease in terrestrial athleticism. This concurs with the findings of previous studies showing ontogenetic decreases in limb bone length and the general scaling principle of a decline of strength : weight ratios with increasing size in animals. Exceptions to isometric scaling found included positive allometry in fascicle length for extensor musculature of both limbs, suggesting an ontogenetic increase in working range interpreted as increasing postural variability - in particular the major hip extensors - the interpretation of which is complicated by previous described ontogenetic increase of moment arms for these muscles.

  6. Functional specialization and ontogenetic scaling of limb anatomy in Alligator mississippiensis

    PubMed Central

    Allen, Vivian; Elsey, Ruth M; Jones, Nicola; Wright, Jordon; Hutchinson, John R

    2010-01-01

    Crocodylians exhibit a fascinating diversity of terrestrial gaits and limb motions that remain poorly described and are of great importance to understanding their natural history and evolution. Their musculoskeletal anatomy is pivotal to this diversity and yet only qualitative studies of muscle-tendon unit anatomy exist. The relative masses and internal architecture (fascicle lengths and physiological cross-sectional areas) of muscles of the pectoral and pelvic limbs of American alligators (Alligator mississippiensis Daudin 1801) were recorded for an ontogenetic series of wild specimens (n = 15, body masses from 0.5 to 60 kg). The data were analysed by reduced major axis regression to determine scaling relationships with body mass. Physiological cross-sectional areas and therefore muscle force-generating capacity were found to be greater in the extensor (anti-gravity) muscles of the pelvic limb than in the pectoral limb, reflecting how crocodylians differ from mammals in having greater loading of the hindlimbs than the forelimbs. Muscle masses and architecture were generally found to scale isometrically with body mass, suggesting an ontogenetic decrease in terrestrial athleticism. This concurs with the findings of previous studies showing ontogenetic decreases in limb bone length and the general scaling principle of a decline of strength : weight ratios with increasing size in animals. Exceptions to isometric scaling found included positive allometry in fascicle length for extensor musculature of both limbs, suggesting an ontogenetic increase in working range interpreted as increasing postural variability – in particular the major hip extensors – the interpretation of which is complicated by previous described ontogenetic increase of moment arms for these muscles. PMID:20148991

  7. Ontogeny of the Middle-Ear Air-Sinus System in Alligator mississippiensis (Archosauria: Crocodylia).

    PubMed

    Dufeau, David L; Witmer, Lawrence M

    2015-01-01

    Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic sinuses invading the cranium. These sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph--indeed archosaurian--evolution is characterized by the evolution of various paratympanic air sinuses, the homologies of which are poorly understood due in large part to the fact that individual sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these sinuses primarily to clarify the anatomical relations of the individual sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic sinuses are simply an allometric function of braincase

  8. Relationship between growth and the pattern of tooth initiation in alligator embryos.

    PubMed

    Osborn, J W

    1998-09-01

    The temporal and spatial patterns in which teeth are initiated in the growing jaws of embryos are constant for a species but different for different species. The sources of the patterns have been explained in two ways. First, they are the outcome of reactions between molecules created at stationary targets and those which diffuse through embryonic tissues (e.g., Edmund, 1960). Second, Osborn (1978) supposed that the patterns mirror the way a (mixed) population of parent cells, the tooth clone, grows. Westergaard and Ferguson (1986, 1987, 1990) concluded, from their observations of the sequence of tooth initiation in alligators, that the complicated sequences in which 20 teeth are initiated in each tooth quadrant could not be explained by jaw growth. The present study attempts to refute this criticism by means of measurements made from the raw data published by Westergaard and Ferguson. These data reveal that new teeth, here called primary teeth, are added at a constant rate at the back of the jaw. Interstitial growth of the cells between primary teeth creates space for secondary teeth in secondary regions. The secondary regions increase in length exponentially with time. The sequence in which teeth are initiated in the growing secondary regions was found to be the same in every part of the upper and lower jaws. It was accurately reproduced by a computer program based on a linear contraction rate of inhibitory zones and exponential growth of secondary regions. The results suggest that the posterior progress zone in alligator embryos grows about 125 microm a day. Newly initiated tooth germs are surrounded by an inhibitory zone about 250 microm in diameter. These zones contract from 20 to 30 microm a day until they are about 170 microm in diameter. The sequences in which tooth positions are initiated in embryos may be more the result of the pattern in which cells escape from molecules that inhibit induction rather than the pattern in which cells create molecules that

  9. alpha-Crystallin A sequences of Alligator mississippiensis and the lizard Tupinambis teguixin: molecular evolution and reptilian phylogeny.

    PubMed

    de Jong, W W; Zweers, A; Versteeg, M; Dessauer, H C; Goodman, M

    1985-11-01

    The amino acid sequences of the eye lens protein alpha-crystallin A from many mammalian and avian species, two frog species, and a dogfish have provided detailed information about the molecular evolution of this protein and allowed some useful inferences about phylogenetic relationships among these species. We now have isolated and sequenced the alpha-crystallins of the American alligator and the common tegu lizard. The reptilian alpha A chains appear to have evolved as slowly as those of other vertebrates, i.e., at two to three amino acid replacements per 100 residues in 100 Myr. The lack of charged replacements and the general types and distribution of replacements also are similar to those in other vertebrate alpha A chains. Maximum-parsimony analyses of the total data set of 67 vertebrate alpha A sequences support the monophyletic origin of alligator, tegu, and birds and favor the grouping of crocodilians and birds as surviving sister groups in the subclass Archosauria.

  10. Necropsy findings in American alligator late-stage embryos and hatchlings from northcentral Florida lakes contaminated with organochlorine pesticides

    USGS Publications Warehouse

    Sepulveda, M.S.; Del, Piero F.; Wiebe, J.J.; Rauschenberger, H.R.; Gross, T.S.

    2006-01-01

    Increased American alligator (Alligator mississippiensis) embryo and neonatal mortality has been reported from several northcentral Florida lakes contaminated with old-use organochlorine pesticides (OCPs). However, a clear relationship among these contaminants and egg viability has not been established, suggesting the involvement of additional factors in these mortalities. Thus, the main objective of this study was to determine the ultimate cause of mortality of American alligator late-stage embryos and hatchlings through the conduction of detailed pathological examinations, and to evaluate better the role of OCPs in these mortalities. Between 2000 and 2001, 236 dead alligators were necropsied at or near hatching (after ???65 days of artificial incubation and up to 1 mo of age posthatch). Dead animals were collected from 18 clutches ranging in viability from 0% to 95%. Total OCP concentrations in yolk ranged from ???100 to 52,000 ??g/kg, wet weight. The most common gross findings were generalized edema (34%) and organ hyperemia (29%), followed by severe emaciation (14%) and gross deformities (3%). Histopathologic examination revealed lesions in 35% of the animals, with over half of the cases being pneumonia, pulmonary edema, and atelectasis. Within and across clutches, dead embryos and hatchlings compared with their live cohorts were significantly smaller and lighter. Although alterations in growth and development were not related to yolk OCPs, there was an increase in prevalence of histologic lesions in clutches with high OCPs. Overall, these results indicate that general growth retardation and respiratory abnormalities were a major contributing factor in observed mortalities and that contaminants may increase the susceptibility of animals to developing certain pathologic conditions. ?? Wildlife Disease Association 2006.

  11. Joint histology in Alligator mississippiensis challenges the identification of synovial joints in fossil archosaurs and inferences of cranial kinesis.

    PubMed

    Bailleul, Alida M; Holliday, Casey M

    2017-03-29

    Archosaurs, like all vertebrates, have different types of joints that allow or restrict cranial kinesis, such as synovial joints and fibrous joints. In general, synovial joints are more kinetic than fibrous joints, because the former possess a fluid-filled cavity and articular cartilage that facilitate movement. Even though there is a considerable lack of data on the microstructure and the structure-function relationships in the joints of extant archosaurs, many functional inferences of cranial kinesis in fossil archosaurs have hinged on the assumption that elongated condylar joints are (i) synovial and/or (ii) kinetic. Cranial joint microstructure was investigated in an ontogenetic series of American alligators, Alligator mississippiensis All the presumably synovial, condylar joints found within the head of the American alligator (the jaw joint, otic joint and laterosphenoid-postorbital (LS-PO) joint) were studied by means of paraffin histology and undecalcified histology paired with micro-computed tomography data to better visualize three-dimensional morphology. Results show that among the three condylar joints of A. mississippiensis, the jaw joint was synovial as expected, but the otherwise immobile otic and LS-PO joints lacked a synovial cavity. Therefore, condylar morphology does not always imply the presence of a synovial articulation nor mobility. These findings reveal an undocumented diversity in the joint structure of alligators and show that crocodylians and birds build novel, kinetic cranial joints differently. This complicates accurate identification of synovial joints and functional inferences of cranial kinesis in fossil archosaurs and tetrapods in general. © 2017 The Author(s).

  12. How Doth the Little Crocodilian: Analyzing the Influence of Environmental Viscosity on Feeding Performance of Juvenile Alligator mississippiensis

    PubMed Central

    Kerfoot, James R.; Easter, Emily; Elsey, Ruth M.

    2016-01-01

    Wetland habitats are used as nursery sites for hatchling and juvenile alligators (Alligator mississippiensis), where they utilize prey from aquatic and terrestrial settings. However, little is known about how viscosity of the medium influences feeding performance. We hypothesized that timing and linear excursion feeding kinematic variables would be different for individuals feeding on prey above the water compared with the same individuals feeding underwater. Individuals were fed immobile fish prey and feeding events were recorded using a high speed video camera. Feeding performance was summarized by analyzing three feeding kinematic variables (maximum gape, maximum gape velocity, duration of feeding bout) and success of strike. Results of a series of paired t-tests indicated no significant difference in kinematic variables between feeding events above water compared with underwater. Similarity in feeding performance could indicate that prey-capture is not altered by environmental viscosity or that feeding behavior can mitigate its influence. Behavioral differences were observed during feeding events with alligators approaching underwater prey having their mouths partially opened versus fully closed when feeding above water. This behavior could be an indication of a strategy used to overcome water viscosity. PMID:27706023

  13. Cadmium and lead residues in field-collected red swamp crayfish (Procambarus clarkii) and uptake by alligator weed, Alternanthera philoxiroides

    SciTech Connect

    Naqvi, S.M.; Howell, R.D.; Sholas, M. . Dept. of Biological Sciences and Health Research Center)

    1993-01-01

    The whole-body residues of Cd and Pb in the tissues of Louisiana swamp crayfish (Procambarus clarkii) were determined by flame AAS technique. Test animals were collected from roadside ditches alongside major highways. The water and soil samples were also collected from the same sites. The mean Cd and Pb concentrations in crayfish tissues were 0.46 and 0.07, respectively. The levels of Cd and Pb in the water were 0.09 and 0.04; and in soil were 2.85 and 0.87 mg/1, respectively. The concentration of cadmium was 32 and Pb 12 times more than in the water. The bioaccumulation factors (BF) for Cd and Pb in crayfish tissues were 5.1 and 1.7, respectively. Alligator weed (Alternanthera philoxiroides) plants were exposed to 0.5 mg/1 Cd-chloride or Pb-nitrate solutions for 3 wk period, thrice. The mean Pb accumulation in roots was 1.31 mg/1, followed by stem (0.078 mg/1), but Cd only accumulated in root (0.83 mg/1). The BF for Pb and Cd in plant tissues were 14.8 and 16.6, respectively. The uptake of metals was time-dependent. These data suggest that although there is no biomagnification of Cd and Pb from alligator weed to crayfish, both metals readily accumulate in field-collected crayfish and laboratory-exposed alligator weed.

  14. How Doth the Little Crocodilian: Analyzing the Influence of Environmental Viscosity on Feeding Performance of Juvenile Alligator mississippiensis.

    PubMed

    Kerfoot, James R; Easter, Emily; Elsey, Ruth M

    2016-09-30

    Wetland habitats are used as nursery sites for hatchling and juvenile alligators (Alligator mississippiensis), where they utilize prey from aquatic and terrestrial settings. However, little is known about how viscosity of the medium influences feeding performance. We hypothesized that timing and linear excursion feeding kinematic variables would be different for individuals feeding on prey above the water compared with the same individuals feeding underwater. Individuals were fed immobile fish prey and feeding events were recorded using a high speed video camera. Feeding performance was summarized by analyzing three feeding kinematic variables (maximum gape, maximum gape velocity, duration of feeding bout) and success of strike. Results of a series of paired t-tests indicated no significant difference in kinematic variables between feeding events above water compared with underwater. Similarity in feeding performance could indicate that prey-capture is not altered by environmental viscosity or that feeding behavior can mitigate its influence. Behavioral differences were observed during feeding events with alligators approaching underwater prey having their mouths partially opened versus fully closed when feeding above water. This behavior could be an indication of a strategy used to overcome water viscosity.

  15. Predicting maternal body burdens of organochlorine pesticides from eggs and evidence of maternal transfer in Alligator mississippiensis

    USGS Publications Warehouse

    Rauschenberger, R.H.; Sepulveda, M.S.; Wiebe, J.J.; Szabo, N.J.; Gross, T.S.

    2004-01-01

    Few data exist regarding maternal-embryonal transfer of organochlorine pesticides (OCPs) in reptiles. The objective of the present study was to evaluate maternal transfer of OCPs in American alligators (Alligator mississippiensis) from low-, intermediate-, and high-OCP-exposure sites. Overall, total OCP burdens ranged from less than 0.8 ppb in blood to more than 44,000 ppb in abdominal adipose tissue (wet wt concentrations). Lipid-adjusted ratios of maternal adipose burdens (total OCPs) to yolk burdens were close to one (0.94 ?? 0.31:1), suggesting that animals were in steady state and that OCPs in eggs originated from adipose lipids. In contrast, lipid-adjusted muscle and liver OCP burdens were greater than yolk OCP burdens, suggesting that lipids in muscle were not utilized during oogenesis and that nonlipid liver tissue sequesters OCPs. Predictive equations were derived for several tissues and several OCP analytes with r2 values ranging from 0.40 to 0.99 (p < 0.05). We suggest that yolk burdens are predictive of maternal tissue burdens for certain tissues and OCPs and that certain OCPs are maternally transferred in the American alligator. Furthermore, we suggest that future studies should investigate the applicability of these predictive equations for assessing maternal exposure in other crocodilian species.

  16. The provenance of alveolar and parabronchial lungs: insights from paleoecology and the discovery of cardiogenic, unidirectional airflow in the American alligator (Alligator mississippiensis).

    PubMed

    Farmer, C G

    2010-01-01

    Birds and mammals evolved greater aerobic abilities than their common ancestor had. This required expansion of the cardiopulmonary system's capacity for gas exchange, but while directional selection for this expanded capacity resulted in extremely similar avian and mammalian hearts, strikingly different lungs arose, and the reasons for this divergence in lung morphology are not understood. In birds, gas exchange occurs in the lungs as air moves through small tubes (parabronchi) in one direction; in mammals, air flows tidally into and out of the alveoli. Here, I present a scenario for the origin of both the alveolar and parabronchial lungs that explains when and how they could have arisen by a gradual sequence of steps. I argue that (1) the alveolar lung evolved in the late Paleozoic, when high levels of atmospheric oxygen relaxed selection for a thin blood-gas barrier within the lung; (2) unidirectional flow originated in the ectothermic ancestral archosaur, the forerunner of birds and crocodilians, to enable the heart to circulate pulmonary gases during apnea. This hypothesis would be supported by a demonstration of unidirectional flow in the lungs of crocodilians, the extant sister taxon of birds. Airflow in the lungs of juvenile alligators was measured during apnea using dual thermistor flowmeters, and cardiac activity was measured with electrocardiography. Coincident with each heartbeat, a pulse of air flowed in the pulmonary conduit under study with a bias in the direction of movement, yielding a net unidirectional flow. These data suggest the internal structures requisite for unidirectional flow were present in the common ancestors of birds and crocodilians and may have preadapted the lungs of archosaurs to function advantageously during the oxygen-poor period of the early Mesozoic.

  17. Altered Sex Hormone Concentrations and Gonadal mRNA Expression Levels of Activin Signaling Factors in Hatchling Alligators From a Contaminated Florida Lake

    PubMed Central

    MOORE, BRANDON C.; KOHNO, SATOMI; COOK, ROBERT W.; ALVERS, ASHLEY L.; HAMLIN, HEATHER J.; WOODRUFF, TERESA K.; GUILLETTE, LOUIS J.

    2014-01-01

    Activins and estrogens participate in regulating the breakdown of ovarian germ cell nests and follicle assembly in mammals. In 1994, our group reported elevated frequencies of abnormal, multioocytic ovarian follicles in 6 month old, environmental contaminant-exposed female alligators after gonadotropin challenge. Here, we investigated if maternal contribution of endocrine disrupting contaminants to the egg subsequently alters estrogen/inhibin/activin signaling in hatchling female offspring, putatively predisposing an increased frequency of multioocytic follicle formation. We quantified basal and exogenous gonadotropin-stimulated concentrations of circulating plasma steroid hormones and ovarian activin signaling factor mRNA abundance in hatchling alligators from the same contaminated (Lake Apopka) and reference (Lake Woodruff) Florida lakes, as examined in 1994. Basal circulating plasma estradiol and testosterone concentrations were greater in alligators from the contaminated environment, whereas activin/inhibin βA subunit and follistatin mRNA abundances were lower than values measured in ovaries from reference lake animals. Challenged, contaminant-exposed animals showed a more robust increase in plasma estradiol concentration following an acute follicle stimulating hormone (FSH) challenge compared with reference site alligators. Aromatase and follistatin mRNA levels increased in response to an extended FSH challenge in the reference site animals, but not in the contaminant-exposed animals. In hatchling alligators, ovarian follicles have not yet formed; therefore, these endocrine differences are likely to affect subsequent ovarian development, including ovarian follicle assembly. PMID:20166196

  18. Altered sex hormone concentrations and gonadal mRNA expression levels of activin signaling factors in hatchling alligators from a contaminated Florida lake.

    PubMed

    Moore, Brandon C; Kohno, Satomi; Cook, Robert W; Alvers, Ashley L; Hamlin, Heather J; Woodruff, Teresa K; Guillette, Louis J

    2010-04-01

    Activins and estrogens participate in regulating the breakdown of ovarian germ cell nests and follicle assembly in mammals. In 1994, our group reported elevated frequencies of abnormal, multioocytic ovarian follicles in 6 month old, environmental contaminant-exposed female alligators after gonadotropin challenge. Here, we investigated if maternal contribution of endocrine disrupting contaminants to the egg subsequently alters estrogen/inhibin/activin signaling in hatchling female offspring, putatively predisposing an increased frequency of multioocytic follicle formation. We quantified basal and exogenous gonadotropin-stimulated concentrations of circulating plasma steroid hormones and ovarian activin signaling factor mRNA abundance in hatchling alligators from the same contaminated (Lake Apopka) and reference (Lake Woodruff) Florida lakes, as examined in 1994. Basal circulating plasma estradiol and testosterone concentrations were greater in alligators from the contaminated environment, whereas activin/inhibin betaA subunit and follistatin mRNA abundances were lower than values measured in ovaries from reference lake animals. Challenged, contaminant-exposed animals showed a more robust increase in plasma estradiol concentration following an acute follicle stimulating hormone (FSH) challenge compared with reference site alligators. Aromatase and follistatin mRNA levels increased in response to an extended FSH challenge in the reference site animals, but not in the contaminant-exposed animals. In hatchling alligators, ovarian follicles have not yet formed; therefore, these endocrine differences are likely to affect subsequent ovarian development, including ovarian follicle assembly. 2010 Wiley-Liss, Inc.

  19. The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

    USGS Publications Warehouse

    Rodda, Gordon H.

    1984-01-01

    Displaced juvenile alligators, Alligator mississipiensis, were released on land in a 9 m diameter dodecagonal arena to test their ability to orient in the absence of terrestrial landmarks. Navigational ability seemed to improve with age. When displaced along a fairly direct route yearlings (age 7–14 months) compensated for their displacement, moving in the direction from the arena to their home sites. When displaced by a circuitous route, yearlings failed to compensate for their displacement, exhibiting instead simple compass orientation in a direction that would have returned them to water had they been released on land near the site where they were captured. The older juveniles were oriented in a homeward direction under all displacement and test conditions. The latter animals may have been using geomagnetic map information to select their homeward directions as the errors in their homeward bearings correlated with small deviations in the geomagnetic field's dip angle at the time of the test (1980r s=−0.6047,P=0.0131, all testsr s= −0.4652,P=0.0084). This effect appeared to depend on a very short-term assessment of geomagnetic conditions, as values measured 20 min before or 30 min after the tests began did not correlate with the directions the animals moved. The older juveniles appeared to use magnetically quiet hours on the night of their capture as the baseline from which to measure the geomagnetic deviations that occurred at the time of the arena test. The magnitude of the magnetic effect in the older animals suggests that the geomagnetic information may have been used to perform a ‘map’ step, as small fluctuations in dip angle correlated with much larger deviations in homeward bearings. In addition, the compass-oriented yearlings and the seemingly route-based behavior of the homeward-oriented yearlings did not appear to be influenced by geomagnetic conditions. These findings have many parallels in results obtained from bird orientation studies

  20. Primary alkaline magmas associated with the Quaternary Alligator Lake volcanic complex, Yukon Territory, Canada

    NASA Astrophysics Data System (ADS)

    Eiché, G. E.; Francis, D. M.; Ludden, J. N.

    1987-02-01

    The Alligator Lake complex is a Quaternary alkaline volcanic center located in the southern Yukon Territory of Canada. It comprises two cinder cones which cap a shield consisting of five distinct lava units of basaltic composition. Units 2 and 3 of this shield are primitive olivine-phyric lavas (13.5 19.5 cation % Mg) which host abundant spinel lherzolite xenoliths, megacrysts, and granitoid fragments. Although the two lava types have erupted coevally from adjacent vents and are petrographically similar, they are chemically distinct. Unit 2 lavas have considerably higher abundances of LREE, LILE, and Fe, but lower HREE, Y, Ca, Si, and Al relative to unit 3 lavas. The 87Sr/86Sr and 143Nd/144Nd isotopic ratios of these two units are, however, indistinguishable. The differences between these two lava types cannot be explained in terms of low pressure olivine fractionation, and the low concentrations of Sr, Nb, P, and Ti in the granitoid xenoliths relative to the primitive lavas discounts differential crustal contamination. The abundance of spinel lherzolite xenoliths and the high Mg contents in the lavas of both units indicates that their compositional differences originated in the upper mantle. The Al and Si systematics of these lavas suggests that, compared to unit 3 magmas, the unit 2 magmas may have segregated at greater depths from a garnet lherzolite mantle. The identical isotopic composition and similar ratios of highly incompatible elements in these two lava units argues against their differences being a consequence of random metasomatism or mantle heterogeneity. The lower Y and HREE contents but higher concentrations of incompatible elements in the unit 2 lavas relative to unit 3 can be most simply explained by differential partial melting of similar garnet-bearing sources. The unit 2 magmas thus appear to have been generated by smaller degrees of melting at a greater depth than the unit 3 magmas. The contemporaneous eruption of two distinct but

  1. Endocrine-disrupting chemical exposure and the American alligator: a review of the potential role of environmental estrogens on the immune system of a top trophic carnivore.

    PubMed

    Finger, John W; Gogal, Robert M

    2013-11-01

    Endocrine-disrupting chemicals (EDCs) alter cellular and organ system homeostasis by interfering with the body's normal physiologic processes. Numerous studies have identified environmental estrogens as modulators of EDC-related processes in crocodilians, notably in sex determination. Other broader studies have shown that environmental estrogens dysregulate normal immune function in mammals, birds, turtles, lizards, fish, and invertebrates; however, the effects of such estrogenic exposures on alligator immune function have not been elucidated. Alligators occupy a top trophic status, which may give them untapped utility as indicators of environmental quality. Environmental estrogens are also prevalent in the waters they occupy. Understanding the effects of these EDCs on alligator immunity is critical for managing and assessing changes in their health and is thus the focus of this review.

  2. Gonadotropin-induced changes in oviducal mRNA expression levels of sex steroid hormone receptors and activin-related signaling factors in the alligator.

    PubMed

    Moore, Brandon C; Forouhar, Sara; Kohno, Satomi; Botteri, Nicole L; Hamlin, Heather J; Guillette, Louis J

    2012-01-15

    Oviducts respond to hormonal cues from ovaries with tissue proliferation and differentiation in preparation of transporting and fostering gametes. These responses produce oviducal microenvironments conducive to reproductive success. Here, we investigated changes in circulating plasma sex steroid hormones concentrations and ovarian and oviducal mRNA expression to an in vivo gonadotropin (FSH) challenge in sexually immature, five-month-old alligators. Further, we investigated differences in these observed responses between alligators hatched from eggs collected at a heavily-polluted (Lake Apopka, FL) and minimally-polluted (Lake Woodruff, FL) site. In oviducts, we measured mRNA expression of estrogen, progesterone, and androgen receptors and also beta A and B subunits which homo- or heterodimerize to produce the transforming growth factor activin. In comparison, minimal inhibin alpha subunit mRNA expression suggests that these oviducts produce a primarily activin-dominated signaling milieu. Ovaries responded to a five-day FSH challenge with increased expression of steroidogenic enzyme mRNA which was concomitant with increased circulating sex steroid hormone concentrations. Oviducts in the FSH-challenged Lake Woodruff alligators increased mRNA expression of progesterone and androgen receptors, proliferating cell nuclear antigen, and the activin signaling antagonist follistatin. In contrast, Lake Apopka alligators displayed a diminished increase in ovarian CYP19A1 aromatase expression and no increase in oviducal AR expression, as compared to those observed in Lake Woodruff alligators. These results demonstrate that five-month-old female alligators display an endocrine-responsive ovarian-oviducal axis and environmental pollution exposure may alter these physiological responses.

  3. Turning crocodilian hearts into bird hearts: growth rates are similar for alligators with and without right-to-left cardiac shunt.

    PubMed

    Eme, John; Gwalthney, June; Owerkowicz, Tomasz; Blank, Jason M; Hicks, James W

    2010-08-01

    The functional and possible adaptive significance of non-avian reptiles' dual aortic arch system and the ability of all non-avian reptiles to perform central vascular cardiac shunts have been of great interest to comparative physiologists. The unique cardiac anatomy of crocodilians - a four-chambered heart with the dual aortic arch system - allows for only right-to-left (R-L; pulmonary bypass) cardiac shunt and for surgical elimination of this shunt. Surgical removal of the R-L shunt, by occluding the left aorta (LAo) upstream and downstream of the foramen of Panizza, results in a crocodilian with an obligatory, avian/mammalian central circulation. In this study, R-L cardiac shunt was eliminated in age-matched, female American alligators (Alligator mississippiensis; 5-7 months of age). We tested the hypothesis that surgical elimination of R-L cardiac shunt would impair growth (a readily measured proxy for fitness) compared with sham-operated, age-matched controls, especially in animals subjected to exhaustive exercise. While regular exercise caused a decrease in size (snout-to-vent length, head length and body mass), elimination of the capacity for R-L cardiac shunt did not greatly reduce animal growth, despite a chronic ventricular enlargement in surgically altered juvenile alligators. We speculate that, despite being slightly smaller, alligators with an occluded LAo would have reached sexual maturity in the same breeding season as control alligators. This study suggests that crocodilian R-L cardiac shunt does not provide an adaptive advantage for juvenile alligator growth and supports the logic that cardiac shunts persist in crocodilians because they have not been selected against.

  4. Turning crocodilian hearts into bird hearts: growth rates are similar for alligators with and without right-to-left cardiac shunt

    PubMed Central

    Eme, John; Gwalthney, June; Owerkowicz, Tomasz; Blank, Jason M.; Hicks, James W.

    2010-01-01

    The functional and possible adaptive significance of non-avian reptiles' dual aortic arch system and the ability of all non-avian reptiles to perform central vascular cardiac shunts have been of great interest to comparative physiologists. The unique cardiac anatomy of crocodilians – a four-chambered heart with the dual aortic arch system – allows for only right-to-left (R–L; pulmonary bypass) cardiac shunt and for surgical elimination of this shunt. Surgical removal of the R–L shunt, by occluding the left aorta (LAo) upstream and downstream of the foramen of Panizza, results in a crocodilian with an obligatory, avian/mammalian central circulation. In this study, R–L cardiac shunt was eliminated in age-matched, female American alligators (Alligator mississippiensis; 5–7 months of age). We tested the hypothesis that surgical elimination of R–L cardiac shunt would impair growth (a readily measured proxy for fitness) compared with sham-operated, age-matched controls, especially in animals subjected to exhaustive exercise. While regular exercise caused a decrease in size (snout-to-vent length, head length and body mass), elimination of the capacity for R–L cardiac shunt did not greatly reduce animal growth, despite a chronic ventricular enlargement in surgically altered juvenile alligators. We speculate that, despite being slightly smaller, alligators with an occluded LAo would have reached sexual maturity in the same breeding season as control alligators. This study suggests that crocodilian R–L cardiac shunt does not provide an adaptive advantage for juvenile alligator growth and supports the logic that cardiac shunts persist in crocodilians because they have not been selected against. PMID:20639429

  5. Gonadotropin-induced changes in oviducal mRNA expression levels of sex steroid hormone receptors and activin-related signaling factors in the alligator

    PubMed Central

    Moore, Brandon C.; Forouhar, Sara; Kohno, Satomi; Botteri, Nicole L.; Hamlin, Heather J.; Guillette, Louis J.

    2011-01-01

    Oviducts respond to hormonal cues from ovaries with tissue proliferation and differentiation in preparation of transporting and fostering gametes. These responses produce oviducal microenvironments conducive to reproductive success. Here we investigated changes in circulating plasma sex steroid hormones concentrations and ovarian and oviducal mRNA expression to an in vivo gonadotropin (FSH) challenge in sexually immature, five-month-old alligators. Further, we investigated differences in these observed responses between alligators hatched from eggs collected at a heavily-polluted (Lake Apopka, FL) and minimally-polluted (Lake Woodruff, FL) site. In oviducts, we measured mRNA expression of estrogen, progesterone, and androgen receptors and also beta A and B subunits which homo- or heterodimerize to produce the transforming growth factor activin. In comparison, minimal inhibin alpha subunit mRNA expression suggests that these oviducts produce a primarily activin-dominated signaling milieu. Ovaries responded to a five-day FSH challenge with increased expression of steroidogenic enzyme mRNA which was concomitant with increased circulating sex steroid hormone concentrations. Oviducts in the FSH-challenged Lake Woodruff alligators increased mRNA expression of progesterone and androgen receptors, proliferating cell nuclear antigen, and the activin signaling antagonist follistatin. In contrast, Lake Apopka alligators displayed a diminished increase in ovarian CYP19A1 aromatase expression and no increase in oviducal AR expression, as compared to those observed in Lake Woodruff alligators. These results demonstrate that five-month-old female alligators display an endocrine-responsive ovarian-oviducal axis and environmental pollution exposure may alter these physiological responses. PMID:22154572

  6. Analysis of chorioallantoic membranes to assess PCB accumulation in American alligators and Loggerhead sea turtles from the coast of South Carolina

    SciTech Connect

    Cobb, G.P.; Wood, P.D.; O`Quinn, M.

    1995-12-31

    Investigation of contaminant burdens in threatened and endangered species is difficult due to the small number of samples that can be collected. Many samples can be collected if the sampling methods are non-lethal and more specifically non-invasive. Analysis of chorioallantoic membranes is demonstrated for American alligators and Loggerhead sea turtles. Significant differences were found in PCB, uptake by alligators from the Ashepoo-Combahee-Edisto Basin reference site and a contaminated site in Winyah Bay. Intrasite and intersite differences in uptake and distribution of PCB homologues were noted. These data will be discussed as they relate to egg viability and embryo development.

  7. Structure and fracture resistance of alligator gar (Atractosteus spatula) armored fish scales.

    PubMed

    Yang, Wen; Gludovatz, Bernd; Zimmermann, Elizabeth A; Bale, Hrishikesh A; Ritchie, Robert O; Meyers, Marc A

    2013-04-01

    The alligator gar is a large fish with flexible armor consisting of ganoid scales. These scales contain a thin layer of ganoine (microhardness ~2.5 GPa) and a bony body (microhardness ~400 MPa), with jagged edges that provide effective protection against predators. We describe here the structure of both ganoine and bony foundation and characterize the mechanical properties and fracture mechanisms. The bony foundation is characterized by two components: a mineralized matrix and parallel arrays of tubules, most of which contain collagen fibers. The spacing of the empty tubules is ~60 μm; the spacing of those filled with collagen fibers is ~7 μm. Using micromechanical testing of such scales in a variable-pressure scanning electron microscope, we identify interactions between propagating cracks and the microstructure, and show that the toughness of the scales increases with crack extension in a classical resistance-curve response from the activation of extrinsic toughening mechanisms. We demonstrate how mechanical damage evolves in these structures, and further identify that the reinforcement of the mineral by the network of collagen fibers is the principal toughening mechanism resisting such damage. Additionally, we define the anisotropy of the toughness of the scales and relate this to the collagen fiber orientation. Published by Elsevier Ltd.

  8. Two modes of motion of the alligator lizard cochlea: measurements and model predictions.

    PubMed

    Aranyosi, A J; Freeman, Dennis M

    2005-09-01

    Measurements of motion of an in vitro preparation of the alligator lizard basilar papilla in response to sound demonstrate elliptical trajectories. These trajectories are consistent with the presence of both a translational and rotational mode of motion. The translational mode is independent of frequency, and the rotational mode has a displacement peak near 5 kHz. These measurements can be explained by a simple mechanical system in which the basilar papilla is supported asymmetrically on the basilar membrane. In a quantitative model, the translational admittance is compliant while the rotational admittance is second order. Best-fit model parameters are consistent with estimates based on anatomy and predict that fluid flow across hair bundles is a primary source of viscous damping. The model predicts that the rotational mode contributes to the high-frequency slopes of auditory nerve fiber tuning curves, providing a physical explanation for a low-pass filter required in models of this cochlea. The combination of modes makes the sensitivity of hair bundles more uniform with radial position than that which would result from pure rotation. A mechanical analogy with the organ of Corti suggests that these two modes of motion may also be present in the mammalian cochlea.

  9. Thermoluminescence and excess 226Ra decay dating of late Quaternary fluvial sands, East Alligator River, Australia

    NASA Astrophysics Data System (ADS)

    Murray, Andrew; Wohl, Ellen; East, Jon

    1992-01-01

    Thermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.

  10. Two modes of motion of the alligator lizard cochlea: Measurements and model predictions

    NASA Astrophysics Data System (ADS)

    Aranyosi, A. J.; Freeman, Dennis M.

    2005-09-01

    Measurements of motion of an in vitro preparation of the alligator lizard basilar papilla in response to sound demonstrate elliptical trajectories. These trajectories are consistent with the presence of both a translational and rotational mode of motion. The translational mode is independent of frequency, and the rotational mode has a displacement peak near 5 kHz. These measurements can be explained by a simple mechanical system in which the basilar papilla is supported asymmetrically on the basilar membrane. In a quantitative model, the translational admittance is compliant while the rotational admittance is second order. Best-fit model parameters are consistent with estimates based on anatomy and predict that fluid flow across hair bundles is a primary source of viscous damping. The model predicts that the rotational mode contributes to the high-frequency slopes of auditory nerve fiber tuning curves, providing a physical explanation for a low-pass filter required in models of this cochlea. The combination of modes makes the sensitivity of hair bundles more uniform with radial position than that which would result from pure rotation. A mechanical analogy with the organ of Corti suggests that these two modes of motion may also be present in the mammalian cochlea.

  11. Invertebrate community composition differs between invasive herb alligator weed and native sedges

    NASA Astrophysics Data System (ADS)

    Bassett, Imogen E.; Paynter, Quentin; Beggs, Jacqueline R.

    2012-05-01

    Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator weed) and native sedges (Isolepis prolifer and Schoenoplectus tabernaemontani) in a New Zealand lake. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Lower invertebrate abundance, richness and proportionally fewer specialists were predicted on A. philoxeroides compared to native sedges, but with greatest differences between A. philoxeroides and S. tabernaemontani. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Invertebrate abundance showed taxa-specific responses, rather than consistently lower abundance on A. philoxeroides. Nevertheless, as predicted, invertebrate fauna of A. philoxeroides was more similar to that of I. prolifer than to S. tabernaemontani. The prediction of a depauperate native fauna on A. philoxeroides received support from some but not all taxa. All vegetation types hosted generalist-dominated invertebrate communities with simple guild structures. The enemy release hypothesis thus had minimal ability to predict patterns in this system. Results suggest the extent of architectural and chemical differences between native and invasive vegetation may be useful in predicting the extent to which they will host different invertebrate communities. However, invertebrate ecology also affects whether invertebrate taxa respond positively or negatively to weed invasion. Thus, exotic vegetation may support distinct invertebrate communities despite similar overall invertebrate abundance to native vegetation.

  12. Sorption of sulphamethoxazole by the biochars derived from rice straw and alligator flag.

    PubMed

    Li, Tingqiang; Han, Xuan; Liang, Chengfeng; Shohag, M J I; Yang, Xiaoe

    2015-01-01

    The sorption ability of sulphamethoxazole (SMX) by biochar derived from rice straw (RS) and alligator flag (AF) at 600°C was studied to assess the ability of biochar as adsorbent to remove SMX from aqueous solution. The results indicated that sorption of SMX by biochars was well described using the Langmuir equation (R2>0.94), and the maximum sorption parameter (Q) of RS (3650 mg kg(-1)) was much higher than that of AF (1963 mg kg(-1)). Temperature had no effect on SMX sorption by biochars, while thermodynamics analysis indicated that the sorption of SMX on both biochars was a spontaneous physical process. The d 250 RS (diameter of RS sieved through 250 µm) and d 150 AF (diameter of AF sieved through 150 µm) showed excellent sorption ability for SMX. The sorption amount of RS was larger than that of AF when pH<7, whereas, the sorption amount of AF surpassed RS when pH≥7. The presence of Cu2+ and/or Cd2+ ion at low concentrations (20 mg L(-1)) significantly (P<0.05) increased the sorption of SMX on both RS and AF. Our study confirms that biochar derived from the wetland plants could be used as effective adsorbents to remove SMX from aqueous solution.

  13. Microhabitat use, home range, and movements of the alligator snapping turtle, Macrochelys temminckii, in Oklahoma

    USGS Publications Warehouse

    Riedle, J.D.; Shipman, P.A.; Fox, S. F.; Leslie, David M.

    2006-01-01

    Little is known about the ecology of the alligator snapping turtle, Macrochelys temminckii, particularly dentography and behavior. To learn more about the species in Oklahoma, we conducted a telemetry project on 2 small streams at Sequoyah National Wildlife Refuge, an 8,417.5-ha refuge located in east-central Oklahoma. Between June 1999 and August 2000, we fitted 19 M. temminckii with ultrasonic telemetry tags and studied turtle movements and microhahitat use. Turtles were checked 2 to 3 times weekly in summer and sporadically in winter. Several microhabitat variables were measured at each turtle location and a random location to help quantify microhabitat use vs. availability. We recorded 147 turtle locations. Turtles were always associated with submerged cover with a high percentage of overhead canopy cover. Turtles used deeper depths in late summer (but not deeper depths than random locations) and deeper depths in mid-winter (and deeper depths than random locations) than in early summer. They used shallower depths than random locations in early summer. This seasonal shift in depth use might be thermoregulatory, although evidence for this is indirect. The mean linear home range for all turtles was 777.8 m. Females had larger home ranges than males, and juveniles had larger home ranges than adults, although the latter was not statistically significant. Macrochelys temminckii used submerged structures as a core site, and stayed at each core site for an average of 12.3 d.

  14. Formation and regression of the corpus luteum of the American alligator

    USGS Publications Warehouse

    Guillette, L.J.; Woodward, A.R.; You-Xiang, Q.; Cox, M.C.; Matter, J.H.; Gross, T.S.

    1995-01-01

    Luteal morphology of the American alligator is unique when compared to other reptiles but is similar to that of its phylogenetic relatives, the birds. The theca is extensively hypertrophied, but the granulosa never fills the cavity formed following the ovulation of the ovum. The formation of the corpus luteum (CL) is correlated with elevated plasma progesterone concentrations, which decline dramatically after oviposition with the onset of luteolysis. Unlike those of most other reptiles, the central luteal cell mass is composed of two cell types; one presumably is derived from the granulosa, whereas the other is from the theca interna. Both cell types are present throughout gravidity but only one cell type is seen during mid to late luteolysis. A significant decline in luteal volume occurs following oviposition and continues throughout the post-oviposition period. The fastest decline in luteal volume occurs in the month immediately after oviposition; this rate then slows. Luteolysis appears to continue for a year or more following oviposition, as distinct structures of luteal origin can still be identified in animals 9 months after oviposition. The size of persistent CL can be used to determine whether a given female oviposited during the previous nesting season. Females with CL having volumes greater than 0.2 cm2 or CL diameters greater than 0.4 cm were active the previous season. 

  15. Direct comparison of the electronic coupling efficiency of sulfur and selenium alligator clips for molecules adsorbed onto gold electrodes

    NASA Astrophysics Data System (ADS)

    Patrone, L.; Palacin, S.; Bourgoin, J. P.

    2003-05-01

    Scanning tunneling microscopy experiments have been performed to compare the electronic coupling provided by S and by Se used as alligator clips for bisthiol- and biselenol-terthiophene molecules adsorbed onto gold. The molecules were inserted in a dodecanethiol (DT) self-assembled monolayer. Their apparent height above the dodecanethiol matrix was used as a measure of the electronic coupling strength corresponding to S and Se, respectively. We show that the insertion behaviors of the two molecules are qualitatively the same, and that Se provides systematically a better coupling link than S, whatever the tunneling conditions.

  16. A moss-covered alligator rests in the sun at KSC. copy form; photos beginning with 99PD are only ava

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On top of what may be a nest on the edge of an algae-coated canal near Schwartz Rd. at Kennedy Space Center, a moss-covered alligator rests while keeping a wary eye open for trespassers. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and usually lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  17. A moss-covered alligator rests in the sun at KSC. copy form; photos beginning with 99PD are only ava

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On top of what may be a nest on the edge of an algae-coated canal near Schwartz Rd. at Kennedy Space Center, a moss-covered alligator rests while keeping a wary eye open for trespassers. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and usually lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  18. Organizational changes to thyroid regulation in Alligator mississippiensis: evidence for predictive adaptive responses.

    PubMed

    Boggs, Ashley S P; Lowers, Russell H; Cloy-McCoy, Jessica A; Guillette, Louis J

    2013-01-01

    During embryonic development, organisms are sensitive to changes in thyroid hormone signaling which can reset the hypothalamic-pituitary-thyroid axis. It has been hypothesized that this developmental programming is a 'predictive adaptive response', a physiological adjustment in accordance with the embryonic environment that will best aid an individual's survival in a similar postnatal environment. When the embryonic environment is a poor predictor of the external environment, the developmental changes are no longer adaptive and can result in disease states. We predicted that endocrine disrupting chemicals (EDCs) and environmentally-based iodide imbalance could lead to developmental changes to the thyroid axis. To explore whether iodide or EDCs could alter developmental programming, we collected American alligator eggs from an estuarine environment with high iodide availability and elevated thyroid-specific EDCs, a freshwater environment contaminated with elevated agriculturally derived EDCs, and a reference freshwater environment. We then incubated them under identical conditions. We examined plasma thyroxine and triiodothyronine concentrations, thyroid gland histology, plasma inorganic iodide, and somatic growth at one week (before external nutrition) and ten months after hatching (on identical diets). Neonates from the estuarine environment were thyrotoxic, expressing follicular cell hyperplasia (p = 0.01) and elevated plasma triiodothyronine concentrations (p = 0.0006) closely tied to plasma iodide concentrations (p = 0.003). Neonates from the freshwater contaminated site were hypothyroid, expressing thyroid follicular cell hyperplasia (p = 0.01) and depressed plasma thyroxine concentrations (p = 0.008). Following a ten month growth period under identical conditions, thyroid histology (hyperplasia p = 0.04; colloid depletion p = 0.01) and somatic growth (body mass p<0.0001; length p = 0.02) remained altered among the contaminated

  19. Ontogeny of the alligator cartilago transiliens and its significance for sauropsid jaw muscle evolution.

    PubMed

    Tsai, Henry P; Holliday, Casey M

    2011-01-01

    The cartilago transiliens is a fibrocartilaginous structure within the jaw muscles of crocodylians. The cartilago transiliens slides between the pterygoid buttress and coronoid region of the lower jaw and connects two muscles historically identified as m. pseudotemporalis superficialis and m. intramandibularis. However, the position of cartilago transiliens, and its anatomical similarities to tendon organs suggest the structure may be a sesamoid linking a single muscle. Incompressible sesamoids often form inside tendons that wrap around bone. However, such structures rarely ossify in reptiles and have thus far received scant attention. We tested the hypothesis that the cartilago transiliens is a sesamoid developed within in one muscle by investigating its structure in an ontogenetic series of Alligator mississippiensis using dissection, 3D imaging, and polarizing and standard light microscopy. In all animals studied, the cartilago transiliens receives collagen fibers and tendon insertions from its two main muscular attachments. However, whereas collagen fibers were continuous within the cartilaginous nodule of younger animals, such continuity decreased in older animals, where the fibrocartilaginous core grew to displace the fibrous region. Whereas several neighboring muscles attached to the fibrous capsule in older individuals, only two muscles had significant contributions to the structure in young animals. Our results indicate that the cartilago transiliens is likely a sesamoid formed within a single muscle (i.e., m. pseudotemporalis superficialis) as it wraps around the pterygoid buttress. This tendon organ is ubiquitous among fossil crocodyliforms indicating it is a relatively ancient, conserved structure associated with the development of the large pterygoid flanges in this clade. Finally, these findings indicate that similar tendon organs exist among potentially homologous muscle groups in birds and turtles, thus impacting inferences of jaw muscle homology

  20. Effect of lymph composition on an in vitro preparation of the alligator lizard cochlea.

    PubMed

    Freeman, D M; Hendrix, D K; Shah, D; Fan, L F; Weiss, T F

    1993-02-01

    The effects of different artificial lymphs on the cochlear duct of the alligator lizard were studied in an in vitro preparation. The duct was dissected and cemented to the glass floor of a chamber that had been filled with an artificial lymph. The vestibular membrane was removed and latex beads (1-5 microns in diameter) were allowed to settle on the endolymphatic surface of the duct. During perfusion with an artificial lymph solution, the positions of beads were measured and video images of the duct were obtained. Artificial lymphs were isosmotic and included artificial endolymph (AE), artificial perilymph (AP), Leibovitz's L-15 culture medium, an AE solution whose calcium concentration was the same as that of AP, and AE and AP solutions in which gluconate was substituted for chloride ions. Results obtained in AE were consistently different from those in other lymphs. The displacements of beads, the projected area of the papilla, the occurrence of blebs, and direct observation of cells in the duct all indicated that the tissue swelled in AE (with or without 2 mmol/l Ca) but showed no consistent shrinking or swelling in any of the other artificial lymphs. Thus for the solutions we used, the presence of both potassium and chloride was required to elicit the swelling response to isosmotic artificial lymphs. There were some regional differences in the swelling response: the swelling of the endolymphatic surface of the tissue in a direction orthogonal to the basilar membrane surface was smaller on the free-standing region of the basilar papilla than either on the tectorial membrane or on the hyaline epithelial cells. The preparation was osmotically stable in AP and in both AE and AP solutions in which gluconate was substituted for chloride ions. After exposure to these solutions for as much as 300 min, the preparation showed no gross signs of deterioration visible with the light microscope, and continued to exhibit a highly specific osmotic response to the composition

  1. Ontogeny of the Alligator Cartilago Transiliens and Its Significance for Sauropsid Jaw Muscle Evolution

    PubMed Central

    Tsai, Henry P.; Holliday, Casey M.

    2011-01-01

    The cartilago transiliens is a fibrocartilaginous structure within the jaw muscles of crocodylians. The cartilago transiliens slides between the pterygoid buttress and coronoid region of the lower jaw and connects two muscles historically identified as m. pseudotemporalis superficialis and m. intramandibularis. However, the position of cartilago transiliens, and its anatomical similarities to tendon organs suggest the structure may be a sesamoid linking a single muscle. Incompressible sesamoids often form inside tendons that wrap around bone. However, such structures rarely ossify in reptiles and have thus far received scant attention. We tested the hypothesis that the cartilago transiliens is a sesamoid developed within in one muscle by investigating its structure in an ontogenetic series of Alligator mississippiensis using dissection, 3D imaging, and polarizing and standard light microscopy. In all animals studied, the cartilago transiliens receives collagen fibers and tendon insertions from its two main muscular attachments. However, whereas collagen fibers were continuous within the cartilaginous nodule of younger animals, such continuity decreased in older animals, where the fibrocartilaginous core grew to displace the fibrous region. Whereas several neighboring muscles attached to the fibrous capsule in older individuals, only two muscles had significant contributions to the structure in young animals. Our results indicate that the cartilago transiliens is likely a sesamoid formed within a single muscle (i.e., m. pseudotemporalis superficialis) as it wraps around the pterygoid buttress. This tendon organ is ubiquitous among fossil crocodyliforms indicating it is a relatively ancient, conserved structure associated with the development of the large pterygoid flanges in this clade. Finally, these findings indicate that similar tendon organs exist among potentially homologous muscle groups in birds and turtles, thus impacting inferences of jaw muscle homology

  2. Infestation of the southern alligator lizard (Squamata: Anguidae) by Ixodes pacificus (Acari: Ixodidae) and its susceptibility to Borrelia burgdorferi.

    PubMed

    Wright, S A; Lane, R S; Clover, J R

    1998-11-01

    To investigate the reservoir potential of the southern alligator lizard, Elgaria multicarinata (Blainville), for the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, 14 lizards were collected from 1 county on each side of the northern Central Valley of California. Seven animals were collected from a Placer County site (Drivers Flat) and a Yolo County site (Cache Creek) where B. burgdorferi had been isolated previously from Ixodes pacificus Cooley & Kohls. Overall, the mean abundance of I. pacificus on all 14 lizards was 34.1 (range, 3-63) for larvae and 11.0 (range, 1-28) for nymphs. In captivity, field-attached I. pacificus larvae and nymphs required, on average, 12.6 (range, 1-37) and 14.4 (range, 5-44) d to feed to repletion, respectively. The prevalence of B. burgdorferi infection in host-seeking I. pacificus nymphs was 1.4% in Cache Creek Canyon and 9.9% in Drivers Flat. Attempts to isolate spirochetes from lizard blood or ticks that had fed on lizards and subsequently molted were unsuccessful as were efforts to cultivate spirochetes in lizard sera. These data suggest that the southern alligator lizard is not a competent reservoir for B. burgdorferi, although it is an important host for I. pacificus subadults.

  3. Mercury contamination in alligators (Melanosuchus niger) from Mamirauá Reservoir (Brazilian Amazon) and human health risk assessment.

    PubMed

    Correia, Jozélia; Cesar, Ricardo; Marsico, Eliane; Diniz, George Tadeu Nunes; Zorro, Mauricio Camargo; Castilhos, Zuleica

    2014-12-01

    Mercury (Hg) concentrations in muscles of wild alligators (Melanosuchus niger) from the Mamirauá Reservoir (a reference area in the Brazilian Amazon) and the human health risks associated with its consumption were assessed. The mean Hg concentration in alligator muscles was 0.407 ± 0.114 μg/g (N = 61). Close to 5 % of the muscle samples showed Hg levels above the World Health Organization guideline for fish consumption (0.5 μg/g). A positive and significant relationship was observed between Hg concentrations in muscle and the age of the specimens. The dose-response approach suggests that close to 27.4 years is required for half of the exposed specimens to attain 0.5 μg/g. The hazard quotient (HQ) is a risk indicator which defines the ratio of exposure level and a toxicological reference dose. HQ resulted above the unity for all the specimens when the ingestion rate for riverine communities (200 g of muscle per day) is considered, indicating the existence of hazard. When the ingestion rate for market consumers (28.57 g/day) is considered, the risks are much lower (mean HQ = 0.55), suggesting that such group is not at risk. The establishment of local and regional ingestion rates for riverine populations and market consumers is extremely recommended.

  4. Comparative anatomy of the paratympanic organ (vitali organ) in the middle ear of birds and non-avian vertebrates: focus on alligators, parakeets and armadillos.

    PubMed

    Neeser, Jason A; von Bartheld, Christopher S

    2002-01-01

    The paratympanic organ (PTO) in the middle ear has been described in numerous bird species, but little is known about the distribution of this presumed lateral line remnant in other vertebrate classes. Here we provide evidence for a PTO in juvenile alligators, and make the first detailed description of its location and relation to ligaments in the reptilian middle ear. The alligator PTO measures about 450 micro m in diameter. The alligator PTO contains hair cells whose cilia extend into a mucous substance within the lumen. The PTO connects though a ligament to the ear drum, suggesting that pressure onto the tympanic membrane might induce fluid movement in the PTO. Labeling of innervating nerve fibers with the fluorescent dye, DiI, indicates that the alligator PTO is connected with the vestibular brainstem. Because all bird species examined possess a PTO except for owls and possibly parakeets, we verified the absence of a PTO in parakeets by examination of serial sections combined with GABA immunolabeling for potential hair cells. Bird species with significant upper beak movement lack a PTO, suggesting that PTO function is incompatible with upper beak movement. We also examined the middle ear of an armadillo, a mammal that has a very basal position within the eutherian phylogenetic tree. A small vesicle with ciliated cells was found, but did not label with a hair-cell specific marker, antibodies to myosin VIIa, and thus is not likely to represent a true PTO. Our evidence for a PTO in a non-avian species, the alligator, together with previous reports suggesting the presence of a PTO in some mammals, indicates that ancestral stem amniotes possessed a PTO, and that the PTO was not a de novo invention of birds. Copyright 2002 S. Karger AG, Basel

  5. Molecular characterization of the Chinese alligator follicle-stimulating hormone β subunit (FSHβ) and its expression during the female reproductive cycle.

    PubMed

    Zhang, Rui; Zhang, Shengzhou; Zhu, Xue; Zhou, Yongkang; Wu, Xiaobing

    2015-05-01

    The Chinese alligator Alligator sinensis is an endangered species endemic to China, it has a highly specialized reproductive pattern with low fecundity. Up to date, little is known about the regulation of its female reproductive cycle. Follicle-stimulating hormone (FSH), a glycoprotein hormone, plays a key role in stimulating and regulating ovarian follicular development and egg production. In this study, the complete FSHβ cDNA from the ovary of the Chinese alligator was obtained for the first time, it consists of 843-bp nucleotides, including 120-bp nucleotides of the 5'-untranslated region (UTR), 396-bp of the open reading frame, and 3'-UTR of 327-bp nucleotides. It encodes a 131-amino acid precursor molecule of FSHβ with a signal peptide of 18 amino acids followed by a mature protein of 113 amino acids. Its deduced amino acid sequence shares high identities with the American alligator (100%) and birds (89-92%). Phylogenetic tree analysis of the FSHβ amino acid sequence indicated that alligators cluster into the bird branch. Tissue distribution analyses indicated that FSHβ mRNA is expressed in ovary, intestine and liver with the highest level in the ovary, while not in stomach, pancreas, heart, thymus and thyroid. Expression of FSHβ in ovary increases in May (breeding prophase) and peaks in July (breeding period), it is maintained at high levels through September, then decreases significantly in November (post-reproductive period) and remains relatively low from January to March (hibernating period). These temporal changes of FSHβ expression implicated that it might play an important role in promoting ovarian development during the female reproductive cycle.

  6. Organochlorine pesticides and thiamine in eggs of largemouth bass and American alligators and their relationship with early life-stage mortality

    USGS Publications Warehouse

    Sepulveda, M.S.; Wiebe, J.J.; Honeyfield, D.C.; Rauschenberger, H.R.; Hinterkopf, J.P.; Johnson, W.E.; Gross, T.S.

    2004-01-01

    Thiamine deficiency has been linked to early mortality syndrome in salmonids in the Great Lakes. This study was conducted to compare thiamine concentrations in American alligators (Alligator mississippiensis) and Florida largemouth bass (Micropterus salmoides floridanus) eggs from sites with high embryo mortality and high exposure to organochlorine pesticides (OCPs) (Lakes Apopka and Griffin, and Emeralda Marsh, Florida, USA) to those from sites that have historically exhibited low embryo mortality and low OCPs (Lakes Woodruff and Orange, Florida). During June-July 2000, 20 alligator clutches were collected from these sites, artificially incubated, and monitored for embryo mortality. Thiamine and OCPs were measured in one egg/clutch. During February 2002, 10 adult female bass were collected from Emeralda Marsh and Lake Woodruff and mature ovaries analyzed for thiamine and OCP concentrations. Although ovaries from the Emeralda Marsh bass contained almost 1,000-fold more OCPs compared with the reference site, Lake Woodruff, there were no differences in thiamine concentrations between sites (11,710 vs. 11,857 pmol/g). In contrast, alligator eggs from the reference site had five times the amount of thiamine compared with the contaminated sites (3,123 vs. 617 pmol/g). Similarly, clutches with > 55% hatch rates had significantly higher concentrations of thiamine compared with clutches with <54% hatch rates (1,119 vs. 201 pmol/g). These results suggest that thiamine deficiency might be playing an important role in alligator embryo survival but not in reproductive failure and recruitment of largemouth bass. The cause(s) of this thiamine deficiency are unknown but might be related to differences in the nutritional value of prey items across the sites studied and/or to the presence of high concentration of contaminants in eggs. ?? Wildlife Disease Association 2004.

  7. Organizational Changes to Thyroid Regulation in Alligator mississippiensis: Evidence for Predictive Adaptive Responses

    PubMed Central

    Boggs, Ashley S. P.; Lowers, Russell H.; Cloy-McCoy, Jessica A.; Guillette, Louis J.

    2013-01-01

    During embryonic development, organisms are sensitive to changes in thyroid hormone signaling which can reset the hypothalamic-pituitary-thyroid axis. It has been hypothesized that this developmental programming is a ‘predictive adaptive response’, a physiological adjustment in accordance with the embryonic environment that will best aid an individual's survival in a similar postnatal environment. When the embryonic environment is a poor predictor of the external environment, the developmental changes are no longer adaptive and can result in disease states. We predicted that endocrine disrupting chemicals (EDCs) and environmentally-based iodide imbalance could lead to developmental changes to the thyroid axis. To explore whether iodide or EDCs could alter developmental programming, we collected American alligator eggs from an estuarine environment with high iodide availability and elevated thyroid-specific EDCs, a freshwater environment contaminated with elevated agriculturally derived EDCs, and a reference freshwater environment. We then incubated them under identical conditions. We examined plasma thyroxine and triiodothyronine concentrations, thyroid gland histology, plasma inorganic iodide, and somatic growth at one week (before external nutrition) and ten months after hatching (on identical diets). Neonates from the estuarine environment were thyrotoxic, expressing follicular cell hyperplasia (p = 0.01) and elevated plasma triiodothyronine concentrations (p = 0.0006) closely tied to plasma iodide concentrations (p = 0.003). Neonates from the freshwater contaminated site were hypothyroid, expressing thyroid follicular cell hyperplasia (p = 0.01) and depressed plasma thyroxine concentrations (p = 0.008). Following a ten month growth period under identical conditions, thyroid histology (hyperplasia p = 0.04; colloid depletion p = 0.01) and somatic growth (body mass p<0.0001; length p = 0.02) remained altered among the

  8. Alligator ridge district, East-Central Nevada: Carlin-type gold mineralization at shallow depths

    USGS Publications Warehouse

    Nutt, C.J.; Hofstra, A.H.

    2003-01-01

    Carlin-type deposits in the Alligator Ridge mining district are present sporadically for 40 km along the north-striking Mooney Basin fault system but are restricted to a 250-m interval of Devonian to Mississippian strata. Their age is bracketed between silicified ca. 45 Ma sedimentary rocks and unaltered 36.5 to 34 Ma volcanic rocks. The silicification is linked to the deposits by its continuity with ore-grade silicification in Devonian-Mississippian strata and by its similar ??18O values (_e1???17???) and trace element signature (As, Sb, Tl, Hg). Eocene reconstruction indicates that the deposits formed at depths of ???300 to 800 m. In comparison to most Carlin-type gold deposits, they have lower Au/Ag, Au grades, and contained Au, more abundant jasperoid, and textural evidence from deposition of an amorphous silica precursor in jasperoid. These differences most likely result from their shallow depth of formation. The peak fluid temperature (_e1???230??C) and large ??18OH2O value shift from the meteroric water line (_e1???20???) suggest that ore fluids were derived from depths of 8 km or more. A magnetotelluric survey indicates that the Mooney Basin fault system penetrates to mid-crustal depths. Deep circulation of meteoric water along the Mooney Basin fault system may have been in response to initial uplift of the East Humboldt-Ruby Mountains metamorphic core complex; convection also may have been promoted by increased heat flow associated with large magnitude extension in the core complex and regional magmatism. Ore fluids ascended along the fault system until they encountered impermeable Devonian and Mississippian shales, at which point they moved laterally through permeable strata in the Devonian Guilmette Formation, Devonian-Mississippian Pilot Shale, Mississippian Joana Limestone, and Mississippian Chainman Shale toward erosional windows where they ascended into Eocene fluvial conglomerates and lake sediments. Most gold precipitated by sulfidation of host

  9. Alligators and Crocodiles Have High Paracellular Absorption of Nutrients, But Differ in Digestive Morphology and Physiology.

    PubMed

    Tracy, Christopher R; McWhorter, Todd J; Gienger, C M; Starck, J Matthias; Medley, Peter; Manolis, S Charlie; Webb, Grahame J W; Christian, Keith A

    2015-12-01

    Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Alligator mississippiensis and Crocodylus porosus in terms of (1) gross and microscopic morphology of the intestine, (2) activity of the membrane-bound digestive enzymes aminopeptidase-N, maltase, and sucrase, and (3) nutrient absorption by carrier-mediated and paracellular pathways. We also measured gut morphology of animals over a larger range of body sizes. The two species showed different allometry of length and mass of the gut, with A. mississippiensis having a steeper increase in intestinal mass with body size, and C. porosus having a steeper increase in intestinal length with body size. Both species showed similar patterns of magnification of the intestinal surface area, with decreasing magnification from the proximal to distal ends of the intestine. Although A. mississippiensis had significantly greater surface-area magnification overall, a compensating significant difference in gut length between species meant that total surface area of the intestine was not significantly different from that of C. porosus. The species differed in enzyme activities, with A. mississippiensis having significantly greater ability to digest carbohydrates relative to protein than did C. porosus. These differences in enzyme activity may help explain the differences in performance between the crocodilian families when on artificial diets. Both A. mississippiensis and C. porosus showed high absorption of 3-O methyl d-glucose (absorbed via both carrier-mediated and paracellular transport), as expected. Both species also showed surprisingly high levels of l-glucose-uptake (absorbed paracellularly), with fractional absorptions as high as those

  10. Gonadal mRNA expression levels of TGFbeta superfamily signaling factors correspond with post-hatching morphological development in American alligators.

    PubMed

    Moore, B C; Hamlin, H J; Botteri, N L; Guillette, L J

    2010-01-01

    Paracrine factor signaling regulates many aspects of vertebrate gonadal development. We investigated key ovarian and testicular morphological markers of the American alligator (Alligator mississippiensis) during the first 5 months post-hatching and correlated gonadal development with mRNA expression levels of a suite of regulatory factors. In both sexes, we observed significant morphology changes, including ovarian follicle assembly and meiotic progression of testicular germ cells. Concomitant with these changes were sexually dimorphic and ontogenetically variable mRNA expressions. In ovaries, FOXL2, aromatase, and follistatin mRNA expression was greater than in testes at all ages. At one week after hatching, we observed ovarian medullary remodeling in association with elevated activin/inhibin beta A subunit, follistatin, and aromatase mRNA expressions. Three and 5 months following hatching and concomitant with follicle assembly, ovaries showed increased mRNA expression levels of GDF9 and the mitotic factor PCNA. In testes, the activin/inhibin alpha and beta B subunit transcript levels were greater than in ovaries at all ages. Elevated testicular expression of GDF9 mRNA levels at 5 months after hatching aligned with increased spermatogenic activity. We propose that the mRNA expression levels and concomitant morphological changes observed here affect the establishment of alligator reproductive health and later fertility. (c) 2010 S. Karger AG, Basel.

  11. Gonadal mRNA Expression Levels of TGFβ Superfamily Signaling Factors Correspond with Post-Hatching Morphological Development in American Alligators

    PubMed Central

    Moore, B.C.; Hamlin, H.J.; Botteri, N.L.; Guillette, L.J.

    2010-01-01

    Paracrine factor signaling regulates many aspects of vertebrate gonadal development. We investigated key ovarian and testicular morphological markers of the American alligator (Alligator mississippiensis) during the first 5 months post-hatching and correlated gonadal development with mRNA expression levels of a suite of regulatory factors. In both sexes, we observed significant morphology changes, including ovarian follicle assembly and meiotic progression of testicular germ cells. Concomitant with these changes were sexually dimorphic and ontogenetically variable mRNA expressions. In ovaries, FOXL2, aromatase, and follistatin mRNA expression was greater than in testes at all ages. At one week after hatching, we observed ovarian medullary remodeling in association with elevated activin/inhibin βA subunit, follistatin, and aromatase mRNA expressions. Three and 5 months following hatching and concomitant with follicle assembly, ovaries showed increased mRNA expression levels of GDF9 and the mitotic factor PCNA. In testes, the activin/inhibin α and βB subunit transcript levels were greater than in ovaries at all ages. Elevated testicular expression of GDF9 mRNA levels at 5 months after hatching aligned with increased spermatogenic activity. We propose that the mRNA expression levels and concomitant morphological changes observed here affect the establishment of alligator reproductive health and later fertility. PMID:20110644

  12. Effect of aqueous extracts of alligator pear seed (Persea americana mill) on blood glucose and histopathology of pancreas in alloxan-induced diabetic rats.

    PubMed

    Edem, Do; Ekanem, Is; Ebong, Pe

    2009-07-01

    Effects of aqueous extract of alligator pear seed on normal and alloxan-induced diabetic rats were investigated in 6 groups of rats (5 rats per group). Test groups were made diabetic with intra-peritoneal injection of alloxan and treated with 300 mg and 600 mg/kg body weight of alligator pear seed extract. Two non-diabetic groups were also administered with 300 mg and 600 mg/kg body weight extract. The levels of blood glucose were examined in all 6 experimental groups. In diabetic rats, blood glucose levels were significantly reduced (p<0.05) by 73.26-78.24% on consumption of the extracts, with greater effect exhibited by the 600 mg/kg extract. In normal rats, blood glucose levels were significantly reduced (p<0.05) by 34.68-38.9% on consumption of the seed extract. Histological studies showed a degenerative effect on the pancreatic islet cells of diabetic rats. The result suggested restorative (protective) effect of the extract on pancreatic islet cells. Administration of aqueous extract of alligator pear seed may contribute significantly to the reduction of blood glucose levels and can be useful in the treatment of diabetes.

  13. Genes

    MedlinePlus

    ... Search Search MedlinePlus GO GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Genes URL of this page: //medlineplus.gov/ency/article/ ...

  14. New insight into the anatomy of the hyolingual apparatus of Alligator mississippiensis and implications for reconstructing feeding in extinct archosaurs

    PubMed Central

    Li, Zhiheng; Clarke, Julia A

    2015-01-01

    Anatomical studies of the cranium of crocodilians motivated by an interest in its function in feeding largely focused on bite force, the jaw apparatus and associated muscles innervated by the trigeminal nerve. However, the ossified and cartilaginous elements of the hyoid and the associated hyolingual muscles, innervated by the facial, hypoglossal and glossopharyngeal nerves, received much less attention. Crocodilians are known to retain what are ancestrally the ‘Rhythmic Hyobranchial Behaviors’ such as buccal oscillation, but show diminished freedom and movement for the hyobranchial apparatus and the tongue in food transport and manipulation. Feeding among crocodilians, generally on larger prey items than other reptilian outgroups, involves passive transport of the food within the mouth. The tongue in extant crocodilians is firmly attached to the buccal floor and shows little movement during feeding. Here, we present a detailed anatomical description of the myology of the hyolingual apparatus of Alligator mississippiensis, utilizing contrast-enhanced micro-computed tomography and dissection. We construct the first three-dimensional (3D) description of hyolingual myology in Alligator mississippiensis and discuss the detailed implications of these data for our understanding of hyolingual muscle homology across Reptilia. These anatomical data and an evaluation of the fossil record of hyoid structures also shed light on the evolution of feeding in Reptilia. Simplification of the hyoid occurs early in the evolution of archosaurs. A hyoid with only one pair of ceratobranchials and a weakly ossified or cartilaginous midline basihyal is ancestral to Archosauriformes. The comparison with non-archosaurian reptilian outgroup demonstrates that loss of the second set of ceratobranchials as well as reduced ossification in basihyal occurred prior to the origin of crown-clade archosaurs, crocodilians and birds. Early modification in feeding ecology appears to characterize the

  15. A thermal history of the Proterozoic East Alligator River Terrain, N.T., Australia: a fission track study

    NASA Astrophysics Data System (ADS)

    Koul, Sohan L.; Wilde, A. R.; Tickoo, Awtar K.

    1988-01-01

    Radiometric data indicate a major thermal event in Proterozoic rocks of the East Alligator River Terrain, at 1870 Ma. These data, together with metamorphic mineral assemblages, demonstrate peak temperatures in excess of 600 ° C, close to the melting temperature of more deeply buried rocks. A cooling rate following peak metamorphism of 3°C/Ma is suggested. Fission-track dates of peak metamorphic phases, however, reveal a thermal event (or events), after 1650 Ma, rather than the peak metamorphic event. This rise in temperature was the result of thermal blanketing of the metamorphic basement by Carpentarian sediments and anomalous radiogenic heat flow from underlying granitoid gneiss. The temperatures so generated (≥ 175 ° C) were insufficient to reset Rb-Sr and K-Ar systems, but are clearly in excess of F.T. annealing temperatures for all the phases investigated. A cooling history, extending over 1000 m.y. and reflecting gradual erosion of the sedimentary cover, is revealed. This history is consistent with the extraordinary tectonic stability of the region. The importance of F.T. studies in establishing a thermal history is underscored, particularly when maximum temperatures experienced were less than those required to reset Rb-Sr and K-Ar systems.

  16. Distribution of endocrine cells in the digestive tract of Alligator sinensis during the active and hibernating period.

    PubMed

    Wang, Huan; Zhang, Shengzhou; Zhou, Naizhen; Wang, Chaolin; Wu, Xiaobing

    2014-10-01

    The digestive tract is the largest endocrine organ in the body; the distribution pattern of endocrine cells varies with different pathological and physiological states. The aim of the present study was to investigate the distributed density of 5-hydroxytryptamine (5-HT), gastrin (GAS), somatostatin (SS) and vasoactive intestinal peptide (VIP) immunoreactive (IR) cells in the digestive tract of Alligator sinensis during the active and hibernating period by immunohistochemical (IHC) method. The results indicated that 5-HT-IR cells were distributed throughout the entire digestive tract, which were most predominant in duodenum and jejunum. The density increased significantly in stomach and duodenum during hibernation. GAS-IR cells were limited in small stomach and small intestine. The density decreased significantly in small stomach during hibernation, while increased in duodenum. What's more, most of the endocrine cells in duodenum were generally spindle shaped with long cytoplasmic processes ending in the lumen during hibernation. SS-IR cells were limited in stomach and small stomach. The density increased in stomach while decreased in small stomach during hibernation, meanwhile, fewer IR cells occurred in small intestine. VIP-IR cells occurred in stomach and small stomach. The density decreased in small stomach, while increased in stomach during hibernation. These results indicated that the endocrine cells in different parts of digestive tract varied differently during hibernation, their changes were adaptive response to the hibernation.

  17. Summary of well construction, testing, and preliminary findings from the Alligator Alley test well, Broward County, Florida

    USGS Publications Warehouse

    Meyer, F.W.

    1988-01-01

    A 2,811-foot deep test well was drilled during 1980 in The Everglades along Alligator Alley as part of the Floridan Regional Aquifer Systems Analysis project. The well was cased 895 feet deep. Hydraulic packers were used to isolate selected zones in the open hole for water samples and measurement of water levels. The well penetrated the surficial and intermediate aquifers into the Floridan aquifer system. The top of the Floridan aquifer system occurs at 770 feet and includes limestone ranging in age from Oligocene to early Eocene. About 67 percent of the total thickness of the Floridan aquifer system was penetrated by the well. The chief water-producing zones in the Floridan aquifer system occur at about 1,030 feet and at about 2,560 feet. The 1,030-foot zone contains brackish artesian groundwater, and the 2,560-foot zone contains salty artesian groundwater similar in composition to seawater. The static water geothermal gradient is indicated, and radiocarbon activities suggest that the saltwater in the lower zone is younger than brackish groundwater in the upper zone. (USGS)

  18. Estrogen Receptor 1 (ESR1; ERα), not ESR2 (ERβ), Modulates Estrogen-Induced Sex Reversal in the American Alligator, a Species With Temperature-Dependent Sex Determination

    PubMed Central

    Bernhard, Melissa C.; Katsu, Yoshinao; Zhu, Jianguo; Bryan, Teresa A.; Doheny, Brenna M.; Iguchi, Taisen; Guillette, Louis J.

    2015-01-01

    All crocodilians and many turtles exhibit temperature-dependent sex determination where the temperature of the incubated egg, during a thermo-sensitive period (TSP), determines the sex of the offspring. Estrogens play a critical role in sex determination in crocodilians and turtles, as it likely does in most nonmammalian vertebrates. Indeed, administration of estrogens during the TSP induces male to female sex reversal at a male-producing temperature (MPT). However, it is not clear how estrogens override the influence of temperature during sex determination in these species. Most vertebrates have 2 forms of nuclear estrogen receptor (ESR): ESR1 (ERα) and ESR2 (ERβ). However, there is no direct evidence concerning which ESR is involved in sex determination, because a specific agonist or antagonist for each ESR has not been tested in nonmammalian species. We identified specific pharmaceutical agonists for each ESR using an in vitro transactivation assay employing American alligator ESR1 and ESR2; these were 4,4′,4′'-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY 200070), respectively. Alligator eggs were exposed to PPT or WAY 200070 at a MPT just before the TSP, and their sex was examined at the last stage of embryonic development. Estradiol-17β and PPT, but not WAY 200070, induced sex reversal at a MPT. PPT-exposed embryos exposed to the highest dose (5.0 μg/g egg weight) exhibited enlargement and advanced differentiation of the Müllerian duct. These results indicate that ESR1 is likely the principal ESR involved in sex reversal as well as embryonic Müllerian duct survival and growth in American alligators. PMID:25714813

  19. Estrogen receptor 1 (ESR1; ERα), not ESR2 (ERβ), modulates estrogen-induced sex reversal in the American alligator, a species with temperature-dependent sex determination.

    PubMed

    Kohno, Satomi; Bernhard, Melissa C; Katsu, Yoshinao; Zhu, Jianguo; Bryan, Teresa A; Doheny, Brenna M; Iguchi, Taisen; Guillette, Louis J

    2015-05-01

    All crocodilians and many turtles exhibit temperature-dependent sex determination where the temperature of the incubated egg, during a thermo-sensitive period (TSP), determines the sex of the offspring. Estrogens play a critical role in sex determination in crocodilians and turtles, as it likely does in most nonmammalian vertebrates. Indeed, administration of estrogens during the TSP induces male to female sex reversal at a male-producing temperature (MPT). However, it is not clear how estrogens override the influence of temperature during sex determination in these species. Most vertebrates have 2 forms of nuclear estrogen receptor (ESR): ESR1 (ERα) and ESR2 (ERβ). However, there is no direct evidence concerning which ESR is involved in sex determination, because a specific agonist or antagonist for each ESR has not been tested in nonmammalian species. We identified specific pharmaceutical agonists for each ESR using an in vitro transactivation assay employing American alligator ESR1 and ESR2; these were 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY 200070), respectively. Alligator eggs were exposed to PPT or WAY 200070 at a MPT just before the TSP, and their sex was examined at the last stage of embryonic development. Estradiol-17β and PPT, but not WAY 200070, induced sex reversal at a MPT. PPT-exposed embryos exposed to the highest dose (5.0 μg/g egg weight) exhibited enlargement and advanced differentiation of the Müllerian duct. These results indicate that ESR1 is likely the principal ESR involved in sex reversal as well as embryonic Müllerian duct survival and growth in American alligators.

  20. Intra-population variation in activity ranges, diel patterns, movement rates, and habitat use of American alligators in a subtropical estuary

    NASA Astrophysics Data System (ADS)

    Rosenblatt, Adam E.; Heithaus, Michael R.; Mazzotti, Frank J.; Cherkiss, Michael; Jeffery, Brian M.

    2013-12-01

    Movement and habitat use patterns are fundamental components of the behaviors of mobile animals and help determine the scale and types of interactions they have with their environments. These behaviors are especially important to quantify for top predators because they can have strong effects on lower trophic levels as well as the wider ecosystem. Many studies of top predator movement and habitat use focus on general population level trends, which may overlook important intra-population variation in behaviors that now appear to be common. In an effort to better understand the prevalence of intra-population variation in top predator movement behaviors and the potential effects of such variation on ecosystem dynamics, we examined the movement and habitat use patterns of a population of adult American alligators (Alligator mississippiensis) in a subtropical estuary for nearly four years. We found that alligators exhibited divergent behaviors with respect to activity ranges, movement rates, and habitat use, and that individualized behaviors were stable over multiple years. We also found that the variations across the three behavioral metrics were correlated such that consistent behavioral types emerged, specifically more exploratory individuals and more sedentary individuals. Our study demonstrates that top predator populations can be characterized by high degrees of intra-population variation in terms of movement and habitat use behaviors that could lead to individuals filling different ecological roles in the same ecosystem. By extension, one-size-fits-all ecosystem and species-specific conservation and management strategies that do not account for potential intra-population variation in top predator behaviors may not produce the desired outcomes in all cases.

  1. Intra-population variation in activity ranges, diel patterns, movement rates, and habitat use of American alligators in a subtropical estuary

    USGS Publications Warehouse

    Rosenblatt, Adam E.; Heithaus, Michael R.; Mazzotti, Frank M; Cherkiss, Michael S.; Jeffery, Brian M.

    2013-01-01

    Movement and habitat use patterns are fundamental components of the behaviors of mobile animals and help determine the scale and types of interactions they have with their environments. These behaviors are especially important to quantify for top predators because they can have strong effects on lower trophic levels as well as the wider ecosystem. Many studies of top predator movement and habitat use focus on general population level trends, which may overlook important intra-population variation in behaviors that now appear to be common. In an effort to better understand the prevalence of intrapopulation variation in top predator movement behaviors and the potential effects of such variation on ecosystem dynamics, we examined the movement and habitat use patterns of a population of adult American alligators (Alligator mississippiensis) in a subtropical estuary for nearly four years. We found that alligators exhibited divergent behaviors with respect to activity ranges, movement rates, and habitat use, and that individualized behaviors were stable over multiple years. We also found that the variations across the three behavioral metrics were correlated such that consistent behavioral types emerged, specifically more exploratory individuals and more sedentary individuals. Our study demonstrates that top predator populations can be characterized by high degrees of intra-population variation in terms of movement and habitat use behaviors that could lead to individuals filling different ecological roles in the same ecosystem. By extension, one-size-fits-all ecosystem and species-specific conservation and management strategies that do not account for potential intra-population variation in top predator behaviors may not produce the desired outcomes in all cases.

  2. Characterization of mineral coatings associated with a Pleistocene-Holocene rock art style: The Northern Running Figures of the East Alligator River region, western Arnhem Land, Australia.

    PubMed

    King, Penelope L; Troitzsch, Ulrike; Jones, Tristen

    2017-02-01

    This data article contains mineralogic and chemical data from mineral coatings associated with rock art from the East Alligator River region. The coatings were collected adjacent to a rock art style known as the "Northern Running Figures" for the purposes of radiocarbon dating (doi:10.1016/j.jasrep.2016.11.016; (T. Jones, V. Levchenko, P.L. King, U. Troitzsch, D. Wesley, 2017) [1]). This contribution includes raw and processed powder X-ray Diffraction data, Scanning Electron Microscopy energy dispersive spectroscopy data, and Fourier Transform infrared spectral data.

  3. Isolation and characterization of microsatellite loci for alligator gar (Atractosteus spatula) and their variability in two other species (Lepisosteus oculatus and L. osseus) of Lepisosteidae

    USGS Publications Warehouse

    Moyer, G.R.; Sloss, Brian L.; Kreiser, B.R.; Feldheim, K.A.

    2009-01-01

    We report on the isolation of 17 polymorphic microsatellite loci from alligator gar (Atractosteus spatula), a large-bodied species that has experienced population declines across much of its range. These loci possessed 2-19 alleles and observed heterozygosities of 0-0.974. All loci conformed to Hardy-Weinberg equilibrium expectations, and none exhibited linkage disequilibrium. Nine and eight of these loci were found to be polymorphic in the related species Lepisosteus oculatus and L. osseus, respectively. These microsatellite loci should prove useful in conservation efforts of A. spatula through the study of population structure and hatchery broodstock management. ?? 2009 Blackwell Publishing Ltd.

  4. EFFECT OF ACUTE STRESS ON PLASMA B-CORTICOSTERONE, ESTRADIOL-17B AND TESTOSTERONE CONCENTRATIONS IN JUVENILE AMERICAN ALLIGATORS COLLECTED FROM THREE SITES WITHIN THE KISSIMMEE-EVERGLADES DRAINAGE BASIN IN FLORIDA (USA)

    EPA Science Inventory

    The effect of acute stress on plasma b-corticosterone (B), testosterone (T) and estradiol-17b (E2), concentrations in juvenile alligators collected from sites with varying sediment contaminants was examined in this study. Dramatic increases in plasma B concentrations were observe...

  5. EFFECT OF ACUTE STRESS ON PLASMA B-CORTICOSTERONE, ESTRADIOL-17B AND TESTOSTERONE CONCENTRATIONS IN JUVENILE AMERICAN ALLIGATORS COLLECTED FROM THREE SITES WITHIN THE KISSIMMEE-EVERGLADES DRAINAGE BASIN IN FLORIDA (USA)

    EPA Science Inventory

    The effect of acute stress on plasma b-corticosterone (B), testosterone (T) and estradiol-17b (E2), concentrations in juvenile alligators collected from sites with varying sediment contaminants was examined in this study. Dramatic increases in plasma B concentrations were observe...

  6. Geologic map of the Alligator Ridge area, including the Buck Mountain East and Mooney Basin Summit quadrangles and parts of the Sunshine Well NE and Long Valley Slough quadrangles, White Pine County, Nevada

    USGS Publications Warehouse

    Nutt, Constance J.

    2000-01-01

    Data set describes the geology of Paleozoic through Quaternary units in the Alligator Ridge area, which hosts disseminated gold deposits. These digital files were used to create the 1:24,000-scale geologic map of the Buck Mountain East and Mooney Basin Summit Quadrangles and parts of the Sunshine Well NE and Long Valley Slough Quadrangles, White Pine County, east-central Nevada.

  7. Effects of incubation temperature and estrogen exposure on aromatase activity in the brain and gonads of embryonic alligators.

    PubMed Central

    Milnes, Matthew R; Roberts, Robert N; Guillette, Louis J

    2002-01-01

    During embryogenesis, incubation temperature and the hormonal environment influence gonadal differentiation of some reptiles, including all crocodilians. Current evidence suggests that aromatase, the enzyme that converts androgens to estrogens, has a role in sexual differentiation of species that exhibit temperature-dependent sex determination (TSD). During the temperature-sensitive period (TSP) of sex determination, we compared aromatase activity in the brain and gonads of putative male and female alligator embryos to determine if aromatase activity in the embryonic brain could provide the hormonal environment necessary for ovarian development in a TSD species. In addition, we assessed the pattern of aromatase activity in the brain and gonads of embryos treated with estradiol-17beta (E(2)) and incubated at male-producing temperatures to compare enzyme activity in E(2) sex-reversed females to control males and females. This has particular significance regarding wildlife species living in areas contaminated with suspected environmental estrogens. Gonadal aromatase activity remained low during the early stages of the TSP in both sexes and increased late in the TSP only in females. Aromatase activity in the brain increased prior to gonadal differentiation in both sexes. These results suggest that aromatase activity in the brain is not directly responsible for mediating differentiation of the gonad. E(2) exposure at male-producing temperatures resulted in sex-reversed females that had intermediate gonad function and masculinized brain activity. This study indicates the need to examine multiple end points and to determine the persistence of developmental alterations in contaminant-exposed wildlife populations. PMID:12060834

  8. Water in the Lithospheric Mantle Beneath a Phanerozoic Continental Belt: FTIR Analyses of Alligator Lake Xenoliths (Yukon, Canada)

    NASA Technical Reports Server (NTRS)

    Gelber, McKensie; Peslier, Ann H.; Brandon, Alan D.

    2015-01-01

    Water in the mantle influences melting, metasomatism, viscosity and electrical conductivity. The Alligator Lake mantle xenolith suite is one of three bimodal peridotite suites from the northern Canadian Cordillera brought to the surface by alkali basalts, i.e., it consists of chemically distinct lherzolites and harzburgites. The lherzolites have equilibration temperatures about 50 C lower than the harzburgites and are thought to represent the fertile upper mantle of the region. The harzburgites might have come from slightly deeper in the mantle and/or be the result of a melting event above an asthenospheric upwelling detected as a seismic anomaly at 400-500 km depth. Major and trace element data are best interpreted as the lherzolite mantle having simultaneously experienced 20-25% partial melting and a metasomatic event to create the harzburgites. Well-characterized xenoliths are being analyzed for water by FTIR. Harzburgites contain 29-52 ppm H2O in orthopyroxene (opx) and (is) approximately140 ppm H2O in clinopyroxene (cpx). The lherzolites have H2O contents of 27-150 ppm in opx and 46-361 ppm in cpx. Despite correlating with enrichments in LREE, the water contents of the harzburgite pyroxenes are low relative to those of typical peridotite xenoli