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Sample records for saltwater crocodiles crocodylus

  1. Spatial resolving power and spectral sensitivity of the saltwater crocodile, Crocodylus porosus, and the freshwater crocodile, Crocodylus johnstoni.

    PubMed

    Nagloo, Nicolas; Collin, Shaun P; Hemmi, Jan M; Hart, Nathan S

    2016-05-01

    Crocodilians are apex amphibious predators that occupy a range of tropical habitats. In this study, we examined whether their semi-aquatic lifestyle and ambush hunting mode are reflected in specific adaptations in the peripheral visual system. Design-based stereology and microspectrophotometry were used to assess spatial resolving power and spectral sensitivity of saltwater (Crocodylus porosus) and freshwater crocodiles (Crocodylus johnstoni). Both species possess a foveal streak that spans the naso-temporal axis and mediates high spatial acuity across the central visual field. The saltwater crocodile and freshwater crocodile have a peak spatial resolving power of 8.8 and 8.0 cycles deg(-1), respectively. Measurement of the outer segment dimensions and spectral absorbance revealed five distinct photoreceptor types consisting of three single cones, one twin cone and a rod. The three single cones (saltwater/freshwater crocodile) are violet (424/426 nm λmax), green (502/510 nm λmax) and red (546/554 nm λmax) sensitive, indicating the potential for trichromatic colour vision. The visual pigments of both members of the twin cones have the same λmax as the red-sensitive single cone and the rod has a λmax at 503/510 nm (saltwater/freshwater). The λmax values of all types of visual pigment occur at longer wavelengths in the freshwater crocodile compared with the saltwater crocodile. Given that there is a greater abundance of long wavelength light in freshwater compared with a saltwater environment, the photoreceptors would be more effective at detecting light in their respective habitats. This suggests that the visual systems of both species are adapted to the photic conditions of their respective ecological niche. PMID:27208035

  2. A genetic linkage map for the saltwater crocodile (Crocodylus porosus)

    PubMed Central

    2009-01-01

    Background Genome elucidation is now in high gear for many organisms, and whilst genetic maps have been developed for a broad array of species, surprisingly, no such maps exist for a crocodilian, or indeed any other non-avian member of the Class Reptilia. Genetic linkage maps are essential tools for the mapping and dissection of complex quantitative trait loci (QTL), and in order to permit systematic genome scans for the identification of genes affecting economically important traits in farmed crocodilians, a comprehensive genetic linage map will be necessary. Results A first-generation genetic linkage map for the saltwater crocodile (Crocodylus porosus) was constructed using 203 microsatellite markers amplified across a two-generation pedigree comprising ten full-sib families from a commercial population at Darwin Crocodile Farm, Northern Territory, Australia. Linkage analyses identified fourteen linkage groups comprising a total of 180 loci, with 23 loci remaining unlinked. Markers were ordered within linkage groups employing a heuristic approach using CRIMAP v3.0 software. The estimated female and male recombination map lengths were 1824.1 and 319.0 centimorgans (cM) respectively, revealing an uncommonly large disparity in recombination map lengths between sexes (ratio of 5.7:1). Conclusion We have generated the first genetic linkage map for a crocodilian, or indeed any other non-avian reptile. The uncommonly large disparity in recombination map lengths confirms previous preliminary evidence of major differences in sex-specific recombination rates in a species that exhibits temperature-dependent sex determination (TSD). However, at this point the reason for this disparity in saltwater crocodiles remains unclear. This map will be a valuable resource for crocodilian researchers, facilitating the systematic genome scans necessary for identifying genes affecting complex traits of economic importance in the crocodile industry. In addition, since many of the markers

  3. Unexpected lower testosterone in faster growing farmed saltwater crocodile (Crocodylus porosus) hatchlings.

    PubMed

    Finger, John W; Thomson, Peter C; Isberg, Sally R

    2016-01-15

    Agricultural production of the saltwater crocodile (Crocodylus porosus) is an emergent industry in northern Australia with many of the factors affecting production remaining unknown. In this study, we sought to expand upon our previous findings of reference corticosterone and immune function by reporting baseline sex hormone levels [testosterone (TEST) and estradiol (ESTR)] and their association with growth. This was achieved by sampling 253 hatchling crocodiles repeatedly at 3, 6, and 9months of age. Sampling age had a significant effect on both TEST (p<0.001) and ESTR (p<0.001) suggesting climatic/abiotic factors have an influence even in prepubescent crocodiles. Stress, as measured by plasma corticosterone, had no detectable effect on plasma ESTR or TEST levels. Unexpectedly however, TEST was higher in slower-growing crocodiles, which is contrary to what has been reported for the American alligator. ESTR was not associated with growth. PMID:26631457

  4. QTL mapping for two commercial traits in farmed saltwater crocodiles (Crocodylus porosus).

    PubMed

    Miles, L G; Isberg, S R; Thomson, P C; Glenn, T C; Lance, S L; Dalzell, P; Moran, C

    2010-04-01

    The recent generation of a genetic linkage map for the saltwater crocodile (Crocodylus porosus) has now made it possible to carry out the systematic searches necessary for the identification of quantitative trait loci (QTL) affecting traits of economic, as well as evolutionary, importance in crocodilians. In this study, we conducted genome-wide scans for two commercially important traits, inventory head length (which is highly correlated with growth rate) and number of scale rows (SR, a skin quality trait), for the existence of QTL in a commercial population of saltwater crocodiles at Darwin Crocodile Farm, Northern Territory, Australia. To account for the uncommonly large difference in sex-specific recombination rates apparent in the saltwater crocodile, a duel mapping strategy was employed. This strategy employed a sib-pair analysis to take advantage of our full-sib pedigree structure, together with a half-sib analysis to account for, and take advantage of, the large difference in sex-specific recombination frequencies. Using these approaches, two putative QTL regions were identified for SR on linkage group 1 (LG1) at 36 cM, and on LG12 at 0 cM. The QTL identified in this investigation represent the first for a crocodilian and indeed for any non-avian member of the Class Reptilia. Mapping of QTL is an important first step towards the identification of genes and causal mutations for commercially important traits and the development of selection tools for implementation in crocodile breeding programmes for the industry. PMID:19917044

  5. Molecular identification of three novel herpesviruses found in Australian farmed saltwater crocodiles (Crocodylus porosus) and Australian captive freshwater crocodiles (Crocodylus johnstoni).

    PubMed

    Hyndman, Timothy H; Shilton, Catherine M; Wellehan, James F X; Davis, Steven; Isberg, Sally R; Phalen, David; Melville, Lorna

    2015-12-31

    As part of a larger investigation into three emerging disease syndromes highlighted by conjunctivitis and pharyngitis, systemic lymphoid proliferation and encephalitis, and lymphonodular skin infiltrates in farmed saltwater crocodiles (Crocodylus porosus) and one emerging syndrome of systemic lymphoid proliferation in captive freshwater crocodiles (Crocodylus johnstoni), cytopathic effects (CPE), including syncytial cell formation, were observed in primary crocodile cell lines exposed to clarified tissue homogenates from affected crocodiles. Ten cell cultures with CPE were then screened for herpesviruses using two broadly-reactive herpesvirus PCRs. Amplicons were obtained from 9 of 10 cell cultures and were sequenced. Three novel herpesviruses were discovered and the phylogenetic analysis of these viruses showed there was a 63% Bayesian posterior probability value supporting these viruses clustering with the subfamily Alphaherpesvirinae, and 100% posterior probability of clustering with a clade containing the Alphaherpesvirinae and other unassigned reptile herpesviruses. It is proposed that they are named Crocodyline herpesvirus (CrHV) 1, 2 and 3. CrHV1 and 2 were only isolated from saltwater crocodiles and CrHV3 was only isolated from freshwater crocodiles. A duplex PCR was designed that was able to detect these herpesviruses in formalin-fixed paraffin-embedded tissues, a sample type that neither of the broadly-reactive PCRs was able to detect these herpesviruses in. This work describes the isolation, molecular detection and phylogeny of these novel herpesviruses but the association that they have with the emerging disease syndromes requires further investigation. PMID:26475649

  6. Pathology of runting in farmed saltwater crocodiles (Crocodylus porosus) in Australia.

    PubMed

    Shilton, C; Brown, G P; Chambers, L; Benedict, S; Davis, S; Aumann, S; Isberg, S R

    2014-09-01

    Extremely poor growth of some individuals within a birth cohort (runting) is a significant problem in crocodile farming. We conducted a pathological investigation to determine if infectious disease is associated with runting in farmed saltwater crocodiles (Crocodylus porosus) and to look for evidence of other etiologies. In each of 2005 and 2007, 10 normal and 10 runt crocodiles, with an average age of 5.5 months and reared under identical conditions, were sampled. Laboratory testing included postmortem; histological examination of a wide variety of tissues (with quantitation of features that were noted subjectively to be different between groups); hematology; serum biochemistry (total protein, albumin, globulins, total calcium, phosphorus, and iron); bacterial culture of liver and spleen (2005 only); viral culture of liver, thymus, tonsil, and spleen using primary crocodile cell lines (2007 only); and serum corticosterone (2007 only). The only evidence of infectious disease was mild cutaneous poxvirus infection in 45% of normal and 40% of runt crocodiles and rare intestinal coccidia in 5% of normal and 15% of runt crocodiles. Bacterial and viral culture did not reveal significant differences between the 2 groups. However, runt crocodiles exhibited significant (P < .05) increases in adrenocortical cell cytoplasmic vacuolation and serum corticosterone, decreased production of bone (osteoporosis), and reduced lymphoid populations in the spleen, tonsil, and thymus. Runts also exhibited moderate anemia, hypoalbuminemia, and mild hypophosphatemia. Taken together, these findings suggest an association between runting and a chronic stress response (hyperactivity of the hypothalamic-pituitary-adrenal axis). PMID:24395912

  7. Genetics and infection dynamics of Paratrichosoma sp in farmed saltwater crocodiles (Crocodylus porosus).

    PubMed

    Lott, M J; Hose, G C; Isberg, S R; Power, M L

    2015-02-01

    Paratrichosoma-associated helminthiasis has been identified in saltwater crocodiles under intensive farming conditions. The development of sustainable integrated management practices is dependent on a detailed understanding of Paratrichosoma population genetics and infection dynamics. This study investigated the genetic relationships of Paratrichosoma sp in a population of commercially farmed saltwater crocodiles, Crocodylus porosus, in northern Australia. 18S ribosomal RNA gene sequence data were obtained from Paratrichosoma sp eggs present in the epidermis of infected animals. A high level of genetic diversity was distributed within the Paratrichosoma sp population (241 variable positions in the 1094 bp alignment), indicating an accelerated rate of nucleotide base-pair substitutions in this genus of nematodes. Several possible environmental correlates of the incidence and intensity of helminthiasis, including season, rainfall, and mean monthly temperature, were investigated by visual inspection of crocodile skins. Stepwise logistic regression revealed a significant negative linear relationship (P = 0.011, R (2) = 32.69 %) between mean monthly rainfall and the incidence of monthly Paratrichosoma-associated helminthiasis. Variation in the severity of Paratrichosoma-associated helminthiasis could not be explained by any of the independent environmental variables included within an ordinal regression analysis. The large genetic diversity in these nematodes indicates a high probability of anthelmintic resistant alleles occurring in the population. We discuss how the spread of these alleles may be mitigated by adopting targeted treatment protocols. PMID:25416333

  8. Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia.

    PubMed

    Fukuda, Yusuke; Manolis, Charlie; Saalfeld, Keith; Zuur, Alain

    2015-01-01

    Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim's size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim's size is highlighted by children's vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006-2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children. PMID:25961294

  9. Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia

    PubMed Central

    Fukuda, Yusuke

    2015-01-01

    Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim’s size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim’s size is highlighted by children’s vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006–2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children. PMID:25961294

  10. Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection.

    PubMed

    Shilton, Catherine M; Jerrett, Ian V; Davis, Steven; Walsh, Susan; Benedict, Suresh; Isberg, Sally R; Webb, Grahame J W; Manolis, Charlie; Hyndman, Timothy H; Phalen, David; Brown, Gregory P; Melville, Lorna

    2016-05-01

    Since 2006, 3 new disease syndromes have emerged in farmed saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia. We describe the syndromes through a retrospective study of laboratory findings from 187 diagnostic cases submitted to Berrimah Veterinary Laboratories between 2005 and 2014. The first syndrome was characterized by conjunctivitis and/or pharyngitis (CP), primarily in hatchlings. Herpesviruses were isolated in primary crocodile cell culture, or were detected by PCR directly from conjunctiva or pharyngeal tissue, in 21 of 39 cases of CP (54%), compared with 9 of 64 crocodiles without the syndrome (14%, p < 0.0001). Chlamydiaceae were detected by PCR in conjunctiva or pharyngeal tissue of 55% of 29 CP cases tested, and of these, 81% also contained herpesvirus. The second syndrome occurred in juveniles and growers exhibiting poor growth, and was characterized histologically by systemic lymphoid proliferation and nonsuppurative encephalitis (SLPE). Herpesviruses were isolated or detected by PCR from at least 1 internal organ in 31 of 33 SLPE cases (94%) compared with 5 of 95 crocodiles without the syndrome (5%, p < 0.0001). The third syndrome, characterized by multifocal lymphohistiocytic infiltration of the dermis (LNS), occurred in 6 harvest-sized crocodiles. Herpesviruses were isolated from at least 1 skin lesion in 4 of these 6 cases. Although our study revealed strong associations between herpesvirus and the CP and SLPE syndromes, the precise nature of the role of herpesvirus, along with the pathogenesis and epidemiology of the syndromes, requires further investigation. PMID:27075848

  11. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): I. reproduction traits.

    PubMed

    Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

    2005-12-01

    Repeatability and phenotypic correlations were estimated for saltwater crocodile reproductive traits. No pedigree information was available to estimate heritability or genetic correlations, because the majority of breeder animals on farms were wild-caught. Moreover, as the age of the female breeders could not be accounted for, egg-size measurements were used as proxies. The reproductive traits investigated were clutch size (total number of eggs laid), number of viable eggs, number of eggs that produced a live, healthy hatchling, hatchability, average snout-vent length of the hatchlings and time of nesting. A second data set was also created comprising binary data of whether or not the female nested. Repeatability estimates ranged from 0.24 to 0.68 for the measurable traits, with phenotypic correlations ranging from -0.15 to 0.86. Repeatability for whether a female nested or not was 0.58 on the underlying scale. Correlations could not be estimated between the measurement and binary traits because of confounding. These estimates are the first published for crocodilian reproduction traits. PMID:16274419

  12. Strong purifying selection in endogenous retroviruses in the saltwater crocodile (Crocodylus porosus) in the Northern Territory of Australia

    PubMed Central

    2012-01-01

    Background Endogenous retroviruses (ERVs) are remnants of exogenous retroviruses that have integrated into the nuclear DNA of a germ-line cell. Here we present the results of a survey into the ERV complement of Crocodylus porosus, the saltwater crocodile, representing 45 individuals from 17 sampling locations in the Northern Territory of Australia. These retroelements were compared with published ERVs from other species of Crocodylia (Crocodilians; alligators, caimans, gharials and crocodiles) as well as representatives from other vertebrates. This study represents one of the first in-depth studies of ERVs within a single reptilian species shedding light on the diversity of ERVs and proliferation mechanisms in crocodilians. Results Analyses of the retroviral pro-pol gene region have corroborated the presence of two major clades of ERVs in C. porosus and revealed 18 potentially functional fragments out of the 227 recovered that encode intact pro-pol ORFs. Interestingly, we have identified some patterns of diversification among those ERVs as well as a novel sequence that suggests the presence of an additional retroviral genus in C. porosus. In addition, considerable diversity but low genetic divergence within one of the C. porosus ERV lineages was identified. Conclusions We propose that the ERV complement of C. porosus has come about through a combination of recent infections and replication of ancestral ERVs. Strong purifying selection acting on these clades suggests that this activity is recent or still occurring in the genome of this species. The discovery of potentially functional elements is an interesting development that warrants further investigation. PMID:23217152

  13. Comparative NMR studies of diffusional water permeability of red blood cells from different species: XVIII platypus (Ornithorhynchus anatinus) and saltwater crocodile (Crocodylus porosus).

    PubMed

    Benga, Gheorghe; Chapman, Bogdan E; Cox, Guy C; Kuchel, Philip W

    2010-07-01

    As part of a programme of comparative measurements of Pd (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be approximately 6.3 microm. Pd was measured by using an Mn2+-doping 1H NMR (nuclear magnetic resonance) technique. The Pd (cm/s) values were relatively low: approximately 2.1 x 10(-3) at 25 degrees C, 2.5 x 10(-3) at 30 degrees C, 3.4 x 10(-3) at 37 degrees C and 4.5 at 42 degrees C for the platypus RBCs and approximately 2.8 x 10(-3) at 25 degrees C, 3.2 x 10(-3) at 30 degrees C, 4.5 x 10(-3) at 37 degrees C and 5.7 x 10(-3) at 42 degrees C for the crocodile RBCs. In parallel with the low water permeability, the Ea,d (activation energy of water diffusion) was relatively high, approximately 35 kJ/mol. These results suggest that "conventional" WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile. PMID:20187871

  14. Sequence analysis and characterisation of virally induced viperin in the saltwater crocodile (Crocodylus porosus).

    PubMed

    Milic, Natalie L; Davis, Steven; Carr, Jillian M; Isberg, Sally; Beard, Michael R; Helbig, Karla J

    2015-07-01

    A number of pathogens have been detected in crocodiles, however little is known about their ability to control these pathogens. The interferon stimulated gene (ISG), viperin, has gained attention recently as an important host protein involved in multiple arms of the immune response. Viperin in concert with a number of other ISGs was upregulated in response to viral nucleic acid mimics and sendai virus in the C. porosus cell line, LV-1, indicating an intact early innate response to viral infection in these animals for the first time. Viperin was cloned from the LV-1 cell line and shown to have similar localisation patterns as human viperin, as well as demonstrating extremely high conservation with the human orthologue, excepting at the N-terminus. Interestingly, C. porosus viperin was also able to inhibit Dengue virus replication in vitro, showing a high level of intact functionality for this protein across divergent animal species, and perhaps demonstrating its importance in the early innate response to pathogens in the animal kingdom. PMID:25766282

  15. The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage.

    PubMed

    Nixon, Brett; Anderson, Amanda L; Smith, Nathan D; McLeod, Robby; Johnston, Stephen D

    2016-05-11

    Although mammalian spermatozoa only acquire functional maturity as they are conveyed through the male (epididymal maturation) and female (capacitation) reproductive tracts, the degree of post-testicular development necessary to achieve fertilization in other vertebrate species remains far less clear. Indeed, despite reports that the epididymis of birds and reptiles is capable of secreting proteins that bind and modify the sperm surface characteristics, it remains unclear whether capacitation is a pre-requisite for fertilization in these species. Using the ancient reptilian Australian saltwater crocodile as a model, this study was undertaken to explore whether reptile sperm do undergo capacitation-like changes following ejaculation. Our studies revealed that crocodile spermatozoa experienced a rapid and sustained, cyclic-AMP mediated increase in progressive motility following incubation under conditions optimized for the induction of capacitation in mammalian species such as the mouse and human. This response was coupled with elevated levels of phosphorylation associated with both protein kinase A and tyrosine kinase substrates, the latter of which were predominantly localized within the sperm flagellum. In findings that also accord with mammalian spermatozoa, we confirmed a homologue of outer dense fibre 2 as one of the principal substrates for tyrosine phosphorylation. Overall, our findings support the concept that crocodile spermatozoa do undergo a process that is homologous to capacitation in preparation for fertilization of an ovum. PMID:27147099

  16. Reference levels for corticosterone and immune function in farmed saltwater crocodiles (Crocodylus porosus) hatchlings using current Code of Practice guidelines.

    PubMed

    Finger, John W; Thomson, Peter C; Adams, Amanda L; Benedict, Suresh; Moran, Christopher; Isberg, Sally R

    2015-02-01

    To determine reference levels for on-farm stressors on immune responsiveness and growth rate, 253 hatchling crocodiles from 11 known breeding pairs were repeatedly measured and blood sampled during their first year. Plasma corticosterone (CORT) was used to quantify baseline stress levels in captive animals and were found to be lower (mean 1.83±SE 0.16 ng/mL) than previously reported in saltwater crocodile hatchlings. Two tests of immune function were also conducted. Innate constitutive immunity was assessed using bacterial killing assays (BKA) against two bacterial species: Escherichia coli and Providencia rettgeri, whereby the latter causes considerable economic loss to industry from septicaemic mortalities. Although the bactericidal capabilities were different at approximately 4 months old (32±3% for E. coli and 16±4% for P. rettgeri), the differences had disappeared by approximately 9 months old (58±2% and 68±6%, respectively). To assess immune responsiveness to a novel antigen, the inflammatory swelling response caused by phytohaemagglutinin (PHA) injection was assessed but was only significantly different between Samplings 1 and 3 (5% LSD). There were no significant clutch effects for CORT or PHA but there were for both BKA traits. CORT was not significantly associated with growth (head length) or the immune parameters except for P. rettgeri BKA where higher CORT levels were associated with better bactericidal capability. As such, these results suggest that the crocodiles in this study are not stressed, therefore endorsing the management strategies adopted within the Australian industry Code of Practice. PMID:25644211

  17. A bacterial artificial chromosome library for the Australian saltwater crocodile (Crocodylus porosus) and its utilization in gene isolation and genome characterization

    PubMed Central

    2009-01-01

    Background Crocodilians (Order Crocodylia) are an ancient vertebrate group of tremendous ecological, social, and evolutionary importance. They are the only extant reptilian members of Archosauria, a monophyletic group that also includes birds, dinosaurs, and pterosaurs. Consequently, crocodilian genomes represent a gateway through which the molecular evolution of avian lineages can be explored. To facilitate comparative genomics within Crocodylia and between crocodilians and other archosaurs, we have constructed a bacterial artificial chromosome (BAC) library for the Australian saltwater crocodile, Crocodylus porosus. This is the first BAC library for a crocodile and only the second BAC resource for a crocodilian. Results The C. porosus BAC library consists of 101,760 individually archived clones stored in 384-well microtiter plates. NotI digestion of random clones indicates an average insert size of 102 kb. Based on a genome size estimate of 2778 Mb, the library affords 3.7 fold (3.7×) coverage of the C. porosus genome. To investigate the utility of the library in studying sequence distribution, probes derived from CR1a and CR1b, two crocodilian CR1-like retrotransposon subfamilies, were hybridized to C. porosus macroarrays. The results indicate that there are a minimum of 20,000 CR1a/b elements in C. porosus and that their distribution throughout the genome is decidedly non-random. To demonstrate the utility of the library in gene isolation, we probed the C. porosus macroarrays with an overgo designed from a C-mos (oocyte maturation factor) partial cDNA. A BAC containing C-mos was identified and the C-mos locus was sequenced. Nucleotide and amino acid sequence alignment of the C. porosus C-mos coding sequence with avian and reptilian C-mos orthologs reveals greater sequence similarity between C. porosus and birds (specifically chicken and zebra finch) than between C. porosus and squamates (green anole). Conclusion We have demonstrated the utility of the

  18. Crocodylus acutus (American Crocodile). Long distance juvenile movement

    USGS Publications Warehouse

    Crespo, Rafael; Beauchamp, Jeffrey S.; Mazzotti, Frank; Cherkiss, Michael S.

    2015-01-01

    Crocodylus acutus (American Crocodile) is the most widely distributed New World crocodilian species with its range extending from Peru in the south to the southern tip of peninsular Florida in the north. Crocodylus acutus occupies primarily coastal brackish water habitat, however it also occurs in freshwater to hypersaline habitats (Thorbjarnarson 2010. In Crocodiles. Status Survey and Conservation Action Plan. [Third Edition], American Crocodile Crocodylus acutus, pp. 46–53 S.C. Manolis and C. Stevenson. Crocodile Specialist Group, Darwin). There is limited literature on long distance movements of juvenile crocodilians worldwide and no literature on juvenile crocodiles in Florida. However, adult C. acutus in Florida have been documented to make seasonal movements of 5–15 km from preferred foraging habitat to nesting beaches (Mazzotti 1983. The Ecology of Crocodylus acutus in Florida. PhD Dissertation. The Pennsylvania State University, University Park, Pennsylvania. 161pp), and one adult was documented making a 35 km trip from her nest site to preferred foraging habitat (Cherkiss et. al. 2006. Herpetol. Rev. 38:72–73). Rodda (1984. Herpetologica 40:444–451) reported on juvenile C. acutus movement in Gatun Lake, Panama, and found that juveniles stayed within 1 km of their nest site for the first month. Movements of juvenile Crocodylus porosus (Saltwater Crocodile) in a river system in Northern Australia showed a maximum movement of 38.9 km from a known nest site, with the majority of the crocodiles staying within 15.6 km downstream to 6.8 km upstream (Webb and Messel 1978. Aust. Wildlife Res. 5:263–283). Juvenile movement of Crocodylus niloticus (Nile Crocodile) in Lake Ngezi, Zimbabwe showed crocodiles restricted their movements from 1.0 km up to 4.5 km through the wet and dry seasons (Hutton 1989. Am. Zool. 29:1033–1049). Long distance movements of alligators were recorded for sizes ranging from 28 cm to 361 cm in a coastal refuge in Louisiana, where

  19. Paraphimosis and amputation in a Nile crocodile (Crocodylus niloticus).

    PubMed

    Lankester, Felix; Hernandez-Divers, Stephen J

    2005-12-01

    A captive Nile crocodile (Crocodylus niloticus) developed recurrent episodes of paraphimosis over a 2-yr period, which eventually led to hemorrhage and obvious inflammation. Two months postsurgery, the crocodile remained clinically normal. PMID:17312729

  20. Comparative genome analyses reveal distinct structure in the saltwater crocodile MHC.

    PubMed

    Jaratlerdsiri, Weerachai; Deakin, Janine; Godinez, Ricardo M; Shan, Xueyan; Peterson, Daniel G; Marthey, Sylvain; Lyons, Eric; McCarthy, Fiona M; Isberg, Sally R; Higgins, Damien P; Chong, Amanda Y; John, John St; Glenn, Travis C; Ray, David A; Gongora, Jaime

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III) containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians) are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus) and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2-6 times longer) than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity) with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs. PMID:25503521

  1. Comparative Genome Analyses Reveal Distinct Structure in the Saltwater Crocodile MHC

    PubMed Central

    Jaratlerdsiri, Weerachai; Deakin, Janine; Godinez, Ricardo M.; Shan, Xueyan; Peterson, Daniel G.; Marthey, Sylvain; Lyons, Eric; McCarthy, Fiona M.; Isberg, Sally R.; Higgins, Damien P.; Chong, Amanda Y.; John, John St; Glenn, Travis C.; Ray, David A.; Gongora, Jaime

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III) containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians) are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus) and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2–6 times longer) than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity) with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs. PMID:25503521

  2. External injuries of Morelet's crocodile Crocodylus moreletii in Campeche, Mexico.

    PubMed

    Padilla, Sergio E; Weber, Manuel

    2016-07-01

    Analysis of external injuries in captive and free-ranging Morelet's crocodiles Crocodylus moreletii was performed in the northern wetlands of Campeche, Mexico. From March to September of 2007, a total of 52 free-ranging and 51 captive Morelet's crocodiles were studied. Captive crocodiles presented significantly more injuries. Sixteen free-ranging crocodiles presented some type of lesion, mostly superficial abrasions. Nineteen captive crocodiles presented lesions, mostly incisions from agonistic interactions. Overall, the injuries with highest prevalence were the incisions. The tail was the most frequently injured body region. Injuries were more common in adults than in other size classes. Conversely, the presence of lesions caused by the parasite Paratrichosoma spp. was greater in crocodiles captured in the coastal channels (mangrove habitat). The information presented here is important to understand some of the effects of individual interactions and to foresee and manage the consequences of conservation and management activities of crocodile populations. PMID:27409238

  3. Remarkable movements of an American crocodile (Crocodylus acutus) in Florida

    USGS Publications Warehouse

    Cherkiss, Michael S.; Mazzotti, Frank J.; Hord, Lindsey; Aldecoa, Mario

    2014-01-01

    Here we present the remarkable movements of an individual Crocodylus acutus (American Crocodile) over a 14-year period. The crocodile was originally marked in Homestead, FL as a young-of-the-year in 1999, and was later recaptured multiple times more than 388 km away along the southwest coast of Florida. After several relocations and numerous sightings, this individual who has become known as Yellow Number 1 was found back within the same canal system in which it was first captured.

  4. Inappropriate feeding practice favors the transmission of Trichinella papuae from wild pigs to saltwater crocodiles in Papua New Guinea.

    PubMed

    Pozio, Edoardo; Owen, Ifor L; Marucci, Gianluca; La Rosa, Giuseppe

    2005-02-28

    The recent discovery of Trichinella zimbabwensis in farmed crocodiles (Crocodilus niloticus) of Zimbabwe and its ability to infect mammals, and the development of both T. zimbabwensis and Trichinella papuae in experimentally infected reptiles led to an investigation of Trichinella infection in saltwater crocodiles (Crocodylus porosus) and in wild pigs (Sus scrofa) of Papua New Guinea, to see if T. papuae also, is present in both cold- and warm-blooded animals. Of 222 crocodiles examined, 47 animals (21.2%), all from Kikori, Gulf Province, were positive for non-encapsulated larvae in the muscles. The greatest number of larvae was found usually in the biceps, with an average of 7 larvae/g. One isolate from a crocodile infected successfully both laboratory rats and mice. Of 81 wild pigs examined, 9 from Bensbach river area (Western Province) and 1 from Kikori area (Gulf Province) were positive for non-encapsulated larvae in the muscles. Trichinella larvae from both saltwater crocodiles and wild pigs have been identified by multiplex-PCR analysis as T. papuae. The sequence analysis of the region within the large subunit ribosomal DNA, known as the expansion segment V, has shown the presence of a molecular marker distinguishing T. papuae isolates of Bensbach river area from those of Kikori area. This marker could be useful to trace back the geographical origin of the infected animal. The epidemiological investigation carried out in the Kikori area has shown that local people catch young crocodiles in the wild and keep them in holding pens for several months, before sending them to the crocodile farm in Lae (Morobe Province). They feed the crocodiles primarily with wild pig meat bought at the local market and also with fish. These results stress the importance of using artificial digestion for routinely screening of swine and crocodiles, and of adopting measures for preventing the spread of infection, such as the proper disposal of carcasses and the adequate freezing of

  5. Organochlorine contaminants in Morelet's crocodile (Crocodylus moreletii) eggs from Belize.

    PubMed

    Wu, T H; Rainwater, T R; Platt, S G; McMurry, S T; Anderson, T A

    2000-03-01

    Non-viable eggs of Morelet's crocodile (Crocodylus moreletii) were collected from Gold Button (GBL) and New River lagoons (NRL) in northern Belize and screened for organochlorine (OC) compounds using gas chromatography (GC) with electron capture detection (ECD). All egg samples from both lagoons (n = 24) tested positive for one or more OCs. Primary contaminants were p,p-DDE and methoxychlor, detected in 100% and 29% of the eggs examined, respectively. Concentrations of individual OC contaminants ranged from 1 ppb (ng chemical/g egg) to > 0.5 ppm (microgram chemical/g egg). Total concentrations of OCs (sum of all OCs) for one egg collected from a nest at GBL reached as high as 0.7 ppm. Sediment samples from both lagoons also tested positive for OCs (lindane, aldrin, methoxychlor, heptachlor epoxide, p,p-DDT, among others). Nest media (soil and plant material) collected from crocodile nests at GBL were positive for p,p-DDT, methoxychlor, aldrin, endosulfan II, and endrin aldehyde. Based on the 24 egg samples analyzed to date, crocodiles from both lagoons are being exposed to OCs. Such exposure may present a health threat to populations of crocodiles in Central America. PMID:10705543

  6. Nile crocodiles, Crocodylus niloticus, and estuarine crocodiles, Crocodylus porosus, show similar osmoregulatory responses on exposure to seawater.

    PubMed

    Taplin, L E; Loveridge, J P

    1988-01-01

    1. Nile crocodiles, reared in fresh water and exposed acutely to seawater, suffer marked dehydration and hypernatraemia. Cloacal urine osmolarity and potassium concentration increased markedly but urine sodium remains low. 2. Hypernatraemia is increased when secretion from the lingual salt glands is prevented. 3. C. niloticus appears not to drink seawater. 4. Similarities in osmoregulatory response between estuarine and Nile crocodiles suggest that the lingual salt glands of C. niloticus are functional in salt water, playing an important role in sodium balance. 5. Significant differences in the function of the renal/cloacal complex of Alligator and Crocodylus emphasize further the differences between these two groups of crocodilian and provide support for the postulated marine ancestry of many or all of the Crocodylidae. PMID:2896574

  7. Normal haematology and blood biochemistry of wild Nile crocodiles (Crocodylus niloticus) in the Okavango Delta, Botswana.

    PubMed

    Lovely, C J; Pittman, J M; Leslie, A J

    2007-09-01

    Wild Nile crocodiles (Crocodylus niloticus) of various size classes were captured in the Okavango Delta, Botswana. Blood was collected from the post occipital sinus and used for the determination of a wide range of haematological and biochemical parameters. These values were compared between the sexes and between 3 size classes. The values were also compared with the limited data available from farmed Nile crocodiles, as well as from other wild Nile crocodiles. The Okavango crocodiles were comparatively anaemic, and had comparatively low total protein and blood glucose levels. There was a high prevalence of Hepatozoon pettiti infection, however, there was no significant difference in haematological values between the infected and uninfected crocodiles. The values reported here will be useful in diagnostic investigations in both zoo and farmed Nile crocodiles. PMID:18237036

  8. Hepatitis in farmed hatchling Nile crocodiles (Crocodylus niloticus) due to chlamydial infection.

    PubMed

    Huchzermeyer, F W; Gerdes, G H; Foggin, C M; Huchzermeyer, K D; Limper, L C

    1994-03-01

    An investigation into the cause of acute mortality in farmed hatchling crocodiles Crocodylus niloticus led to the isolation of chlamydia from the livers of affected animals. Prominent pathological finds were acute hepatitis with intracellular chlamydial colonies and generalized oedema. A chlamydia presumed to be C. psittaci was isolated from livers of affected hatchlings. Mortality subsided after treatment with oxytetracycline. This disease is now recognized as being a major problem on crocodile farms in Zimbabwe. PMID:7745587

  9. Oral and cloacal microflora of wild crocodiles Crocodylus acutus and C. moreletii in the Mexican Caribbean.

    PubMed

    Charruau, Pierre; Pérez-Flores, Jonathan; Pérez-Juárez, José G; Cedeño-Vázquez, J Rogelio; Rosas-Carmona, Rebeca

    2012-02-17

    Bacterial cultures and chemical analyses were performed from cloacal and oral swabs taken from 43 American crocodiles Crocodylus acutus and 28 Morelet's crocodiles C. moreletii captured in Quintana Roo State, Mexico. We recovered 47 bacterial species (28 genera and 14 families) from all samples with 51.1% of these belonging to the family Enterobacteriaceae. Fourteen species (29.8%) were detected in both crocodile species and 18 (38.3%) and 15 (31.9%) species were only detected in American and Morelet's crocodiles, respectively. We recovered 35 bacterial species from all oral samples, of which 9 (25.8%) were detected in both crocodile species. From all cloacal samples, we recovered 21 bacterial species, of which 8 (38.1%) were detected in both crocodile species. The most commonly isolated bacteria in cloacal samples were Aeromonas hydrophila and Escherichia coli, whereas in oral samples the most common bacteria were A. hydrophila and Arcanobacterium pyogenes. The bacteria isolated represent a potential threat to crocodile health during conditions of stress and a threat to human health through crocodile bites, crocodile meat consumption or carrying out activities in crocodile habitat. We especially warn about the presence of Salmonella arizonae and S. typhi, which cause enteritis and septicemia in crocodiles and salmonellosis and typhoid fever in humans. The risk of bacterial contamination from crocodiles to humans could increase in the future because of the accelerated destruction of crocodile habitat, which could lead to an augmentation of human-crocodile interactions. Information on bacterial diversity reported here could help in the choice of antibacterial products in case of infections that are of crocodile origin. PMID:22422127

  10. Encephalitozoon hellem Infection in a Captive Juvenile Freshwater Crocodile (Crocodylus johnstoni).

    PubMed

    Scheelings, T F; Slocombe, R F; Crameri, S; Hair, S

    2015-11-01

    Microsporidiosis is reported rarely in reptiles and has never been reported in any species of crocodilian. Microsporidiosis was diagnosed histologically in a juvenile captive freshwater crocodile (Crocodylus johnstoni) that was found suddenly dead in its enclosure. Ultrastructural and molecular testing revealed infection to be due to Encephalitozoon hellem. This is the first report of E. hellem infection in any species of reptile. PMID:26386870

  11. Aggressive behaviour in immature captive Nile crocodiles, Crocodylus niloticus, in relation to feeding.

    PubMed

    Morpurgo, B; Gvaryahu, G; Robinzon, B

    1993-06-01

    This study presents five aspects of aggressive behaviour in juvenile Nile crocodiles, Crocodylus niloticus, as observed in five cohorts of 6-18 month-old animals. During this period, the animals grew from a range of 35-55 cm, to a range of 65-115 cm. 1) Stock density related to aggression: decrease in density resulted in significant decrease in the frequency of agonistic events, with 0.64 events/100 crocodiles/min observed in a density of 6.7 crocodiles/m2, compared to 0.26 events/100 crocodiles/min observed in a density of 4.7 crocodiles/m2. 2) Aggression during feeding: in all five groups, there was a significantly higher level of aggression during feeding times. 3) Aggression related to body size: the largest crocodiles were the most aggressive group in agonistic events, mainly against the smallest ones. The largest group, the medium sized, was the least involved in agonistic events. 4) Aggression related to food preference: crocodile food preference was live fish > live chicks > dead fish > ground meat. Except for one food type (live chicks), a significant (p < 0.05) correlation was found between food preference and feeding related aggression in the prey diet groups. 5) Aggression related to an artificial selection for size: removal of the largest crocodiles (which formed 30% of the stock) from the population caused a dramatic decrease in all forms of aggressive behaviour. PMID:8346299

  12. Body condition of Morelet’s Crocodiles (Crocodylus moreletii) from northern Belize

    USGS Publications Warehouse

    Mazzotti, Frank J.; Cherkiss, Michael S.; Brandt, Laura A.; Fujisaki, Ikuko; Hart, Kristen; Jeffery, Brian; McMurry, Scott T.; Platt, Steven G.; Rainwater, Thomas R.; Vinci, Joy

    2012-01-01

    Body condition factors have been used as an indicator of health and well-being of crocodilians. We evaluated body condition of Morelet's Crocodiles (Crocodylus moreletii) in northern Belize in relation to biotic (size, sex, and habitat) and abiotic (location, water level, and air temperature) factors. We also tested the hypothesis that high water levels and warm temperatures combine or interact to result in a decrease in body condition. Size class, temperature, and water level explained 20% of the variability in condition of Morelet's Crocodiles in this study. We found that adult crocodiles had higher condition scores than juveniles/subadults but that sex, habitat, and site had no effect. We confirmed our hypothesis that warm temperatures and high water levels interact to decrease body condition. We related body condition of Morelet's Crocodiles to natural fluctuations in air temperatures and water levels in northern Belize, providing baseline conditions for population and ecosystem monitoring.

  13. Effects of recombinant human growth hormone in juvenile Nile crocodiles (Crocodylus niloticus).

    PubMed

    Andersen, O; Kimwele, C; Aulie, A; Kanui, T

    1990-01-01

    1. Recombinant human growth hormone (hGH) showed somatotropic activity in juvenile Nile crocodiles (Crocodylus niloticus). 2. Body weight of crocodiles receiving 3.25 micrograms hGH/g body weight twice a week was increased by 49% after five weeks of treatment, compared to 31% increase in controls. 3. Total length was increased by 15 and 5%, respectively, in the two groups. 4. Food conversion efficiency increased from 28% in the controls to 36% in the hormone injected animals. 5. Cessation of hormone treatment was followed by reduced appetite and decreasing body growth. PMID:1981037

  14. Genetic and morphological evidence of a geographically widespread hybrid zone between two crocodile species, Crocodylus acutus and Crocodylus moreletii.

    PubMed

    Pacheco-Sierra, Gualberto; Gompert, Zachariah; Domínguez-Laso, Jerónimo; Vázquez-Domínguez, Ella

    2016-07-01

    Hybrid zones represent natural laboratories to study gene flow, divergence and the nature of species boundaries between closely related taxa. We evaluated the level and extent of hybridization between Crocodylus moreletii and Crocodylus acutus using genetic and morphological data on 300 crocodiles from 65 localities. To our knowledge, this is the first genetic study that includes the entire historic range and sympatric zone of the two species. Contrary to expectations, Bayesian admixture proportions and maximum-likelihood estimates of hybrid indexes revealed that most sampled crocodiles were admixed and that the hybrid zone is geographically extensive, extending well beyond their historical region of sympatry. We identified a few geographically isolated, nonadmixed populations of both parental species. Hybrids do not appear to be F1 s or recent backcrosses, but rather are more likely later-generation hybrids, suggesting that hybridization has been going on for several to many generations and is mostly the result of natural processes. Crocodylus moreletii is not the sister species of C. acutus, suggesting that the hybrid zone formed from secondary contact rather than primary divergence. Nonadmixed individuals from the two species were distinguishable based on morphological characters, whereas hybrids had a complex mosaic of morphological characters that hinders identification in the wild. Very few nonadmixed C. acutus and C. moreletii populations exist in the wild. Consequently, the last nonadmixed C. moreletii populations have become critically endangered. Indeed, not only the parental species but also the naturally occurring hybrids should be considered for their potential conservation value. PMID:27164458

  15. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus).

    PubMed

    Myburgh, Jan G; Huchzermeyer, Fritz W; Soley, John T; Booyse, Dirk G; Groenewald, Herman B; Bekker, Lizette C; Iguchi, Taisen; Guillette, Louis J

    2012-01-01

    Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus) was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or small diameter stomach tubes. Based on the gross anatomical features of the cloaca of the Nile crocodile, it was confirmed that urine accumulates in a chamber consisting of the urodeum and coprodeum. Faecal material is stored temporarily in the very short rectum, which is separated from the urinary chamber by the rectocoprodeal sphincter. PMID:23327128

  16. Surveys of endogenous retroviruses (ERVs) in the freshwater crocodile (Crocodylus johnstoni) suggest that ERVs in Crocodylus spp. vary between species.

    PubMed

    Chong, Amanda Y; Kjeldsen, Shannon R; Gongora, Jaime

    2015-04-01

    Endogenous retroviruses (ERVs) are one of many families of transposable elements present in vertebrate genomes. We have examined the ERV complement of the freshwater crocodile (Crocodylus johnstoni) in order to investigate the diversity of ERVs present and possibility of ERV or retroviral activity in a diseased individual of this species. Amplification and sequencing of the highly conserved retroviral pro-pol domains revealed high levels of sequence variation in these ERVs. Phylogenetic analyses of these ERVs and those previously identified in other crocodilian species suggest that although many crocodilians share the same ERV lineages, the relative numbers of retroelement insertions from each of these lineages may vary greatly between species. The data generated in this study provide evidence for the presence of a unique and varied complement of ERVs in crocodilians. This study has also demonstrated the presence of species-specific evolution in ancient retroviral infections. PMID:25653017

  17. Development of an ELISA to detect the humoral immune response to Trichinella zimbabwensis in Nile crocodiles (Crocodylus niloticus).

    PubMed

    Ludovisi, Alessandra; La Grange, Louis Jacobus; Gómez Morales, Maria Angeles; Pozio, Edoardo

    2013-05-20

    Crocodiles are known reservoir hosts of Trichinella papuae and Trichinella zimbabwensis, two zoonotic parasites that also infect mammals. Since commercial crocodile farming represents a key source of income in several countries, it is important to monitor this nematode infection in both farmed crocodiles and in breeding stocks which are frequently introduced from the wild. For this purpose, an indirect ELISA was developed to detect the anti-Trichinella immune response in crocodile sera. New Zealand rabbits were immunized with pooled sera from non-infected farmed crocodiles in the presence of Freund's complete adjuvant. The anti-crocodile serum was then conjugated with horseradish peroxidase. Serum samples from four Nile crocodiles (Crocodylus niloticus) experimentally infected with T. zimbabwensis and from four uninfected crocodiles were used to set up the ELISA. The larval burden per gram of muscle tissue was determined by muscle biopsy. The test was performed on serum samples from an additional 15 experimentally infected crocodiles as well as eight wild Nile crocodiles. Among the 19 experimentally infected crocodiles, seroconversion was observed in 11 animals. The highest antibody response was observed six weeks post infection (p.i.), but in most of these animals, antibodies were not detectable after six weeks p.i. even though live larvae were present in the muscles up to six months p.i. PMID:23433644

  18. Evidence of multiple paternity in Morelet's Crocodile (Crocodylus moreletii) in Belize, CA, inferred from microsatellite markers.

    PubMed

    McVay, John D; Rodriguez, David; Rainwater, Thomas R; Dever, Jennifer A; Platt, Steven G; McMurry, Scott T; Forstner, Michael R J; Densmore, Llewellyn D

    2008-12-01

    Microsatellite data were generated from hatchlings collected from ten nests of Morelet's Crocodile (Crocodylus moreletii) from New River Lagoon and Gold Button Lagoon in Belize to test for evidence of multiple paternity. Nine microsatellite loci were genotyped for 188 individuals from the 10 nests, alongside 42 nonhatchlings from Gold Button Lagoon. Then mitochondrial control region sequences were generated for the nonhatchlings and for one individual from each nest to test for presence of C. acutus-like haplotypes. Analyses of five of the nine microsatellite loci revealed evidence that progeny from five of the ten nests were sired by at least two males. These data suggest the presence of multiple paternity as a mating strategy in the true crocodiles. This information may be useful in the application of conservation and management techniques to the 12 species in this genus, most of which are threatened or endangered. PMID:18831002

  19. Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat samples from three selected farms in Zimbabwe.

    PubMed

    Makanyanga, Tsitsi B; Mutema, Gideon; Mukarati, Norman L; Chikerema, Sylvester M; Makaya, Pious V; Musari, Shuvai; Matope, Gift

    2014-01-17

    Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat from three farms in Zimbabwe was assessed based on 2051 samples collected for pre-export testing during 2006 to 2011. Data were perused by season and year in terms of aerobic plate (APC), coliform (CC), Escherichia coli (ECC) and Listeria monocytogenes (LMC) counts and the presence of Salmonella spp. The log10-transformed data were compared among the farms and seasons using the Kruskal-Wallis test. Microbial quality of the samples was graded based on the EC No. 2073.2005 criteria for beef. The mean APC and CC for the crocodile meat differed significantly (P=0.000) among the farms with the highest APC (3.2±0.05 log10 cfu/g) and the lowest (2.7±0.05 log10 cfu/g) recorded from farms A and C, respectively. There were no significant differences (P>0.05) in ECC and LMC among the farms, while Salmonella spp. were only isolated from one farm. Although the microbial quality of frozen crocodile meat from these farms was generally within acceptable limits, the isolation of E. coli and Salmonella spp. is of public health concern. Thus, implementing of measures to control the pasteurizing process and to minimize bacterial contamination of crocodile meat after pasteurization need to be carefully considered. PMID:24291179

  20. Osmoregulation of the Nile crocodile, Crocodylus niloticus, in Lake St. Lucia, Kwazulu/Natal, South Africa.

    PubMed

    Leslie, A J; Spotila, J R

    2000-07-01

    Nile crocodiles of three age classes, hatched in captivity and reared in fresh water, when exposed acutely to water of 17 and 35 ppt NaCl, suffered marked dehydration, were lethargic, ceased to feed and lost mass. When exposed to gradually increasing salinities (3-35 ppt), with a short acclimation period at each salinity, crocodiles survived, continued to feed and increased in mass and size. All age classes had a relatively constant plasma osmolality across the salinity spectrum. Cloacal urine osmolality varied throughout the acclimation experiment, but did not increase with increasing salinity. No significant increase was found in plasma concentrations of any of the osmolytes. There was a trend of decreasing cloacal urine [Na(+)] and [Cl(-)] and increasing cloacal urine [K(+)] with increased salinity, indicating that urine was not an important route for Na(+) and Cl(-) excretion. Crocodiles exposed to saline conditions maintained relatively constant plasma uric acid concentrations, but urinary uric acid concentrations increased markedly with increasing salinities. This suggests that uric acid is the main constituent of nitrogenous waste excretion in saline exposed Nile crocodiles. As in Crocodylus porosus, C.niloticus has the physiological ability to survive and thrive in periodically hyper-osmotic environments. However, its euryhalinity is restricted, in that acute exposure to sea water leads to dehydration, but with an acclimation period at lower salinities, it survives and thrives in sea water. PMID:10964030

  1. Blood lead concentrations in free-ranging Nile crocodiles (Crocodylus niloticus) from South Africa.

    PubMed

    Warner, Jonathan K; Combrink, Xander; Myburgh, Jan G; Downs, Colleen T

    2016-07-01

    Generally crocodilians have received little attention with regard to the effects of lead toxicity despite their trophic status as apex, generalist predators that utilize both aquatic and terrestrial habitats, thereby exposing them to a potentially wide range of environmental contaminants. During July-October 2010 we collected whole blood from 34 sub-adult and adult free-ranging Nile crocodiles (Crocodylus niloticus) from three separate populations in northeastern South Africa in order to analyze their blood lead concentrations (BPb). Concentrations ranged from below detectability (<3 μg/dL, n = 8) to 960 μg/dL for an adult male at the Lake St Lucia Estuary. Blood lead concentrations averaged 8.15 μg/dL (SD = 7.47) for females and 98.10 μg/dL (SD = 217.42) for males. Eighteen individuals (53 %) had elevated BPbs (≥10 μg/dL). We assessed 12 general linear models using Akaike's Information Criterion (AIC) and found no significant statistical effects among the parameters of sex, crocodile size and population sampled. On average, crocodiles had higher BPbs at Lake St Lucia than at Ndumo Game Reserve or Kosi Bay, which we attribute to lead sinker ingestion during normal gastrolith acquisition. No clinical effects of lead toxicosis were observed in these crocodiles, even though the highest concentration (960 μg/dL) we report represents the most elevated BPb recorded to date for a free-ranging vertebrate. Although we suggest adult Nile crocodiles are likely tolerant of elevated Pb body burdens, experimental studies on other crocodilian species suggest the BPb levels reported here may have harmful or fatal effects to egg development and hatchling health. In light of recent Nile crocodile nesting declines in South Africa we urge further BPb monitoring and ecotoxicology research on reproductive females and embryos. PMID:27038476

  2. Isolation of Serratia fonticola from skin lesions in a Nile Crocodile (Crocodylus niloticus) with an associated septicaemia.

    PubMed

    Garcia, Marta E; Lanzarot, Pilar; Costas, Eduardo; Lopez Rodas, Victoria; Marín, Mercedes; Blanco, Jose L

    2008-05-01

    This paper describes the first isolation of Serratia fonticola in a Nile Crocodile (Crocodylus niloticus). This organism was initially isolated from skin lesions and blood and subsequently from a variety of organs during necropsy. S. fonticola was confirmed as the pathogen causing the infection. PMID:17451977

  3. Antibacterial activity of plasma from crocodile (Crocodylus siamensis) against pathogenic bacteria

    PubMed Central

    2012-01-01

    Background The Siamese crocodile (Crocodylus siamensis) is a critically endangered species of freshwater crocodiles. Crocodilians live with opportunistic bacterial infection but normally suffer no adverse effects. They are not totally immune to microbial infection, but their resistance thereto is remarkably effective. In this study, crude and purified plasma extracted from the Siamese crocodile were examined for antibacterial activity against clinically isolated, human pathogenic bacterial strains and the related reference strains. Methods Crude plasma was prepared from whole blood of the Siamese crocodile by differential sedimentation. The crude plasma was examined for antibacterial activity by the liquid growth inhibition assay. The scanning electron microscopy was performed to confirm the effect of crude crocodile plasma on the cells of Salmonella typhi ATCC 11778. Effect of crude crocodile plasma on cell viability was tested by MTT assay. In addition, the plasma was purified by anion exchange column chromatography with DEAE-Toyopearl 650 M and the purified plasma was tested for antibacterial activity. Results Crude plasma was prepared from whole blood of the Siamese crocodile and exhibited substantial antibacterial activities of more than 40% growth inhibition against the six reference strains of Staphylococcus aureus, Salmonella typhi, Escherichia coli, Vibrio cholerae, Pseudomonas aeruginosa, and Staphylococcus epidermidis, and the four clinical isolates of Staphylococcus epidermidis, Pseudomonas aeruginosa, Salmonella typhi, and Vibrio cholerae. Especially, more than 80% growth inhibition was found in the reference strains of Salmonella typhi, Vibrio cholerae, and Staphylococcus epidermidis and in the clinical isolates of Salmonella typhi and Vibrio cholerae. The effect of the crude plasma on bacterial cells of Salmonella typhi, a certain antibacterial material probably penetrates progressively into the cytoplasmic space, perturbing and damaging bacterial

  4. Kupffer cell structure in the juvenile Nile crocodile, Crocodylus niloticus.

    PubMed

    van Wilpe, Erna; Groenewald, Hermanus Bernardus

    2014-01-01

    The morphology of Kupffer cells was examined in the liver of the juvenile Nile crocodile using light microscopy and transmission electron microscopy. Pleomorphic Kupffer cells were located in the sinusoids, in the space of Disse, in the hepatic parenchyma and often connected adjacent sinusoids. The cell surfaces were irregular due to the presence of filopodia and lamelliapodia with phagocytosis of white blood cells, red blood cells and thrombocytes being evident. The cells were in close contact with endothelial cells and pit cells in the sinusoidal lumen and with stellate cells in the space of Disse. The cytoplasm contained large phagosomes comprising a combination of ceroid pigment, melanosomes and siderosomes. The nuclei were often indented and eccentrically placed due to the presence of the phagosomes. Conspicuous clusters of membrane-bound tubular organelles with a filamentous or crystalline interior were observed in the cytoplasm. The clusters were sometimes separated into smaller groups around phagosomes. A clear zone existed between the limiting membrane and the interior of these tubular organelles with the electron-dense interior profiles being, respectively, circular, angular or divided. The tubular organelles have not previously been described in Kupffer cells and possibly represent lysosomes with specialized functions. Mitochondria, microtubules, Golgi profiles, granular and smooth endoplasmic reticulum, and a few cytoplasmic lipid droplets were also present. The presence of the tubular organelles and the occurrence of the Kupffer cells in different locations in the liver of the juvenile Nile crocodile are indicative of particularly active and mobile cells. PMID:24142864

  5. Non-invasive assessment of adrenocortical function in captive Nile crocodiles (Crocodylus niloticus).

    PubMed

    Ganswindt, Stefanie B; Myburgh, Jan G; Cameron, Elissa Z; Ganswindt, Andre

    2014-11-01

    The occurrence of stress-inducing factors in captive crocodilians is a concern, since chronic stress can negatively affect animal health and reproduction, and hence production. Monitoring stress in wild crocodiles could also be beneficial for assessing the state of health in populations which are potentially threatened by environmental pollution. In both cases, a non-invasive approach to assess adrenocortical function as a measure of stress would be preferable, as animals are not disturbed during sample collection, and therefore sampling is feedback-free. So far, however, such a non-invasive method has not been established for any crocodilian species. As an initial step, we therefore examined the suitability of two enzyme-immunoassays, detecting faecal glucocorticoid metabolites (FGMs) with a 11β,21-diol-20-one and 5β-3α-ol-11-one structure, respectively, for monitoring stress-related physiological responses in captive Nile crocodiles (Crocodylus niloticus). An adrenocorticotropic hormone (ACTH) challenge was performed on 10 sub-adult crocodiles, resulting in an overall increase in serum corticosterone levels of 272% above the pre-injection levels 5h post-injection. Saline-treated control animals (n=8) showed an overall increase of 156% in serum corticosterone levels 5h post-administration. Faecal samples pre- and post-injection could be obtained from three of the six individually housed crocodiles, resulting in FGM concentrations 136-380% above pre-injection levels, always detected in the first sample collected post-treatment (7-15 days post-injection). FGM concentrations seem comparatively stable at ambient temperatures for up to 72 h post-defaecation. In conclusion, non-invasive hormone monitoring can be used for assessing adrenocortical function in captive Nile crocodiles based on FGM analysis. PMID:25066028

  6. Development of an enzyme-linked immunosorbent assay for vitellogenin of Morelet's crocodile (Crocodylus moreletii).

    PubMed

    Selcer, Kyle W; Nespoli, Lisa M; Rainwater, Thomas R; Finger, Adam G; Ray, David A; Platt, Steven G; Smith, Philip N; Densmore, Llewellyn D; McMurry, Scott T

    2006-05-01

    The purpose of this study was to develop an immunoassay for vitellogenin in Morelet's crocodile (Crocodylus moreletii). Blood was collected from wild-caught crocodiles in Belize. Plasma samples from adult females taken during the breeding season were used for vitellogenin purification and samples from adult males were used for comparison. No differences were detected between males and females for plasma total protein concentration, as measured by Coomassie assay. However, denaturing polyacrylamide gel electrophoresis (SDS-PAGE) revealed that female plasma contained a 210-kDa protein, presumably the vitellogenin monomer, that was absent in adult male plasma. The identity of the putative vitellogenin was confirmed by its cross-reactivity in Western blots with a vitellogenin antiserum that was generated against a conserved vitellogenin peptide sequence. Crocodile vitellogenin was purified by two successive rounds of DEAE chromatography. The purified protein had an apparent molecular mass of 450 kDa, as determined by gel filtration chromatography, and 210 kDa on SDS-PAGE. An indirect enzyme-linked immunosorbent assay (ELISA) was then developed for C. moreletii vitellogenin. The detection limit of the assay was 20.0 ng/mL. The intra- and inter-assay coefficients of variation were 5.3% and 9.8%, respectively. The recovery of vitellogenin diluted into male plasma was 94.7%. The ELISA assay revealed that vitellogenin levels of adult female plasma during the breeding season ranged from 1.8 to 3.1 mg/mL with a mean of 2.5+/-0.25 mg/mL. No vitellogenin was detected in adult male plasma. Induction of vitellogenin in Morelet's crocodile may be a useful model system for field studies of crocodile reproduction and for investigations of endocrine disruption in this species. PMID:16448857

  7. Scaling of standard metabolic rate in estuarine crocodiles Crocodylus porosus.

    PubMed

    Seymour, Roger S; Gienger, C M; Brien, Matthew L; Tracy, Christopher R; Charlie Manolis, S; Webb, Grahame J W; Christian, Keith A

    2013-05-01

    Standard metabolic rate (SMR, ml O2 min(-1)) of captive Crocodylus porosus at 30 °C scales with body mass (kg) according to the equation, SMR = 1.01 M(0.829), in animals ranging in body mass of 3.3 orders of magnitude (0.19-389 kg). The exponent is significantly higher than 0.75, so does not conform to quarter-power scaling theory, but rather is likely an emergent property with no single explanation. SMR at 1 kg body mass is similar to the literature for C. porosus and for alligators. The high exponent is not related to feeding, growth, or obesity of captive animals. The log-transformed data appear slightly curved, mainly because SMR is somewhat low in many of the largest animals (291-389 kg). A 3-parameter model is scarcely different from the linear one, but reveals a declining exponent between 0.862 and 0.798. A non-linear model on arithmetic axes overestimates SMR in 70% of the smallest animals and does not satisfactorily represent the data. PMID:23233168

  8. Metals and metallothioneins in Morelet's crocodile (Crocodylus moreletii) from a transboundary river between Mexico and Belize.

    PubMed

    Buenfil-Rojas, A M; Álvarez-Legorreta, T; Cedeño-Vázquez, J R

    2015-02-01

    The aim of this study was to determine concentrations of heavy metals (cadmium [Cd] and mercury [Hg]) and metallothioneins (MTs) in blood plasma and caudal scutes of Morelet's crocodile (Crocodylus moreletii) from Rio Hondo, a river and natural border between Mexico and Belize. Three transects of the river (approximately 20 km each) were surveyed in September 2012 and April 2013, and samples were collected from 24 crocodiles from these areas. In blood plasma, Cd (7.6 ± 9.6 ng/ml) was detected in 69 % of samples (n = 9); Hg (12.2 ± 9.2 ng/ml) was detected in 46 % of samples (n = 6); and MTs (10,900 ± 9,400 ng/ml) were detected in 92 % of samples (n = 12). In caudal scutes samples, Cd (31.7 ± 39.4 ng/g) was detected in 84 % of samples (n = 12) and Hg (374.1 ± 429.4 ng/g) in 83 % of samples (n = 20). No MTs were detected in caudal scutes. Hg concentrations in scutes from the Rio Hondo were 2- to 5-fold greater than those previously reported in scutes from other localities in northern Belize. In blood plasma, a significant positive relationship between Hg and body size was observed. Mean concentrations of Cd and MTs in size classes suggest that MTs may be related to Cd exposure. This is the first report of MT presence in crocodile blood. PMID:25355289

  9. Aeromonas hydrophila-associated skin lesions and septicaemia in a Nile crocodile (Crocodylus niloticus).

    PubMed

    Turutoglu, H; Ercelik, S; Corlu, M

    2005-03-01

    Aeromonas hydrophila is one of the most common bacteria associated with the aquatic environment. There are, however, limited data on A. hydrophila infection in crocodilians. The aim of this report is to describe a case of skin lesions and septicaemia associated with A. hydrophila in a Nile crocodile (Crocodylus niloticus). A captive male crocodile in the Zoological Park of Antalya (Turkey) was found dead without showing signs of any disease. Gross examination showed brown or red-spotted skin lesions of varying size. These lesions were mostly scattered over the abdomen and occasionally on the tail and feet. At necropsy, numerous white, multifocal and randomly distributed areas were seen on the liver. Gram-stained smears from skin and liver lesions showed Gram-negative bacilli arranged in clusters. Pure cultures of A. hydrophila were recovered from skin, internal organs and blood. Isolates were found to be susceptible to ceftiofur, amoxicillin + clavulanic acid, oxytetracycline, enrofloxacin, danofloxacin, neomycin, gentamicin, and lincomycin + neomycin. A pathogenicity test was performed using this isolate on 4 male 2-year-old New Zealand white rabbits. Local abscesses formed in 2 rabbits injected subcutaneously and the 2 that were injected intraperitoneally died as a result of septicaemia. In conclusion, this report has shown that A. hydrophila may cause skin lesions and even death due to septicaemia in crocodiles. PMID:15900900

  10. Nuclear organization and morphology of serotonergic neurons in the brain of the Nile crocodile, Crocodylus niloticus.

    PubMed

    Rodrigues, Stacey-Lee; Maseko, Busisiwe C; Ihunwo, Amadi O; Fuxe, Kjell; Manger, Paul R

    2008-01-01

    The present study describes the location and nuclear organization of the serotonergic system in a representative of the order Crocodylia, the Nile crocodile (Crocodylus niloticus). We found evidence for serotonergic neurons in three regions of the brain, including the diencephalon, rostral and caudal brainstem, as previously reported in several other species of reptile. Within the diencephalon we found neurons in the periventricular organ of the hypothalamus, but not in the infundibular recess as noted in some other reptilian species. In addition we found serotonergic neurons in the pretectal nucleus, this being the first description of these neurons in any species. Within the rostral brainstem we found medial and lateral divisions of the superior raphe nucleus and a widely dispersed group of neurons in the tegmentum, the superior reticular nucleus. In the caudal brainstem we observed the inferior raphe nucleus and the inferior reticular nucleus. While much of the serotonergic system of the Nile crocodile is similar to that seen in other reptiles the entire suite of features appears to distinguish the crocodile studied from the members of the Squamate (lizards and snakes) and Testudine (turtles, tortoises and terrapins) reptiles previously studied. The observations are suggestive of order-specific patterns of nuclear organization of this system in the reptiles, reflecting potential evolutionary constraints in the mutability of the nuclear organization as seen for similar systems in mammals. PMID:17923387

  11. An investigation of antioxidant and anti-inflammatory activities from blood components of Crocodile (Crocodylus siamensis).

    PubMed

    Phosri, Santi; Mahakunakorn, Pramote; Lueangsakulthai, Jiraporn; Jangpromma, Nisachon; Swatsitang, Prasan; Daduang, Sakda; Dhiravisit, Apisak; Thammasirirak, Sompong

    2014-10-01

    Antioxidant and anti-inflammatory activities were found from Crocodylus siamensis (C. siamensis) blood. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, nitric oxide scavenging, hydroxyl radical scavenging and linoleic peroxidation assays were used to investigate the antioxidant activities of the crocodile blood. Results show that crocodile blood components had antioxidant activity, especially hemoglobin (40.58 % nitric oxide radical inhibition), crude leukocyte extract (78 % linoleic peroxidation inhibition) and plasma (57.27 % hydroxyl radical inhibition). Additionally, the anti-inflammatory activity of the crocodile blood was studied using murine macrophage (RAW 264.7) as a model. The results show that hemoglobin, crude leukocyte extract and plasma were not toxic to RAW 264.7 cells. Also they showed anti-inflammatory activity by reduced nitric oxide (NO) and interleukin 6 (IL-6) productions from lipopolysaccharide (LPS)-stimulated cells. The NO inhibition percentages of hemoglobin, crude leukocyte extract and plasma were 31.9, 48.24 and 44.27 %, respectively. However, only crude leukocyte extract could inhibit IL-6 production. So, the results of this research directly indicate that hemoglobin, crude leukocyte extract and plasma of C. siamensis blood provide both antioxidant and anti-inflammatory activities, which could be used as a supplementary agent in pharmaceutical products. PMID:25216803

  12. The occurrence of Trichinella zimbabwensis in naturally infected wild crocodiles (Crocodylus niloticus) from the Kruger National Park, South Africa.

    PubMed

    La Grange, L J; Govender, D; Mukaratirwa, S

    2013-03-01

    Trichinella zimbabwensis has been found naturally infecting crocodiles (Crocodylus niloticus) in Zimbabwe, Mozambique, Ethiopia and South Africa, as well as monitor lizards (Varanus niloticus) in Zimbabwe. The reports on natural infections were mostly accidental rather than structured surveys and involved very few animals. Previous surveillance studies in South Africa reported a 38.5% prevalence of T. zimbabwensis among wild crocodiles tested from the Mpumalanga province and Kruger National Park (KNP). No studies have been conducted to date on the geographical distribution and occurrence of T. zimbabwensis in wild crocodiles and varans in countries in southern Africa. Recent outbreaks of pansteatitis in crocodile populations of the KNP, South Africa, provided an opportunity to conduct a more structured survey aimed at elucidating the occurrence and distribution of T. zimbabwensis in culled wild crocodile populations within the KNP. Results from this study showed that T. zimbabwensis occurred in 10 out of 12 culled crocodiles form the KNP. The results also showed that the natural distribution of T. zimbabwensis in crocodiles includes all the major river systems in the KNP. The predilection sites of larvae in muscles followed a different pattern in naturally infected crocodiles compared to observations in experimentally infected mammalian hosts. PMID:22335961

  13. Mycoplasma-associated polyarthritis in farmed crocodiles (Crocodylus niloticus) in Zimbabwe.

    PubMed

    Mohan, K; Foggin, C M; Muvavarirwa, P; Honywill, J; Pawandiwa, A

    1995-03-01

    Outbreaks of polyarthritis in farmed crocodiles (Crocodylus niloticus) on five farms in Zimbabwe are described. Cases were reported only among the rearing stock aged 1-3 years. No breeding stock suffered. Morbidity was about 10% and the mortality even lower. All the sick animals consistently displayed swollen limb joints as well as progressive lameness and paresis. The synovial structures in subacute cases contained mycoplasmas and excess turbid mucus which, at a later stage of the disease, became yellowish, inspissated and sterile. Cellular changes in the joint capsule included oedema, necrosis of the superficial layers of membrane, lymphocytic infiltration and fibrosis. Evidence of pneumonia was observed only at necropsies. Fifteen isolates of Mycoplasma were cultured from the clinical specimens collected from the four sick and three dead crocodiles. The affected joints of all these animals yielded Mycoplasma in pure culture, but the culture from lungs yielded post-mortem invaders also. The sick animals were treated with a single intramuscular injection of long-acting tetracycline (10 mg/kg), and oxytetracycline mixed in feed at 550 mg/kg was fed for 10 d. The treatment appeared to be effective in ameliorating the clinical signs, but in some cases inflammatory swelling persisted. All 15 the isolates conformed to the characteristics of the genus Mycoplasma, and were serologically indistinguishable in growth-inhibition (Gl) tests. Although these isolates shared the main biochemical characteristics of Mycoplasma capricolum, they differed serologically. Also goats were refractory to experimental infection with crocodile strains. In crocodile yearlings, however, the disease was reproduced with an isolate from one of the affected farms. The source of infection remained elusive.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8539034

  14. Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus).

    PubMed

    Christie, Ian; Reiner, Jessica L; Bowden, John A; Botha, Hannes; Cantu, Theresa M; Govender, Danny; Guillette, Matthew P; Lowers, Russell H; Luus-Powell, Wilmien J; Pienaar, Danie; Smit, Willem J; Guillette, Louis J

    2016-07-01

    Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area. PMID:27038902

  15. Nesting phenology and clutch characteristics of captive Siamese crocodiles (Crocodylus siamensis) in Cambodia.

    PubMed

    Platt, Steven G; Monyrath, Vuthy; Sovannara, Heng; Kheng, Long; Rainwater, Thomas R

    2012-01-01

    The Siamese crocodile (Crocodylus siamensis) is considered one of the least studied and most critically endangered crocodilians in the world. Although few wild populations remain, more than 700,000 C. siamensis are held on commercial crocodile farms in Southeast Asia. Despite conservation concerns, many aspects of C. siamensis life history remain poorly known, particularly with regards to its reproductive biology. We studied nesting phenology, clutch characteristics, and other aspects of C. siamensis reproductive biology on crocodile farms in Cambodia during 2000 and 2001. Oviposition among captive crocodiles began in February and continued into early June. The mean (±1 SD) oviposition date based on pooled data from 2000 and 2001 was 5 April ± 24 days. Mean oviposition date differed significantly between 2000 and 2001, possibly as a result of annual variability among nesting cues. The mean incubation period was 72 ± 3 days and eggs hatched from 5 May to 18 August. Mean clutch size (25.0 ± 8.8 eggs; n = 183) differed significantly between years, possibly resulting from the >2.5-fold increase in sample size during 2001. There was no correlation between clutch size and oviposition date during either 2000 or 2001. A single female produced two clutches during 2001, complimenting previous reports of double-clutching among C. siamensis. The mean length and width of 515 eggs were 78.2 ± 4.9 and 48.1 ± 2.5 mm, respectively; mean egg mass was 90.8 ± 16.5 g (n = 471). One unpipped egg contained a set of twins. PMID:23027550

  16. Some helminth parasites from Morelet's crocodile, Crocodylus moreletii, from Yucatan, Mexico.

    PubMed

    Moravec, F

    2001-01-01

    An examination of three specimens of the Morelet's crocodile, Crocodylus moreletii Duméril et Bibron, from the Lagoon of Celestún, Yucatan, Mexico revealed the presence of the following eight helminth species: Acanthostomum americanum (Pérez Vigueras, 1956), Pelaezia loossi (Pérez Vigueras, 1956), Telorchis sp. juv., Pseudoneodiplostomum groschafti sp. n. (all trematodes), Dujardinascaris helicina (Molin, 1860), Contracaecum sp. Type 2 larvae, Micropleura sp. and Paratrichosoma recurvum (Solger, 1877) (all nematodes). Pseudoneodiplostomum groschafti sp. n. is established by indication based on the description of specimens from Crocodylus rhombifer from Cuba, given by Groschaft and Barus (1970). Acanthostomum acuti Caballero et Brennes, 1959 is considered a synonym of A. americanum. A. americanum and D. helicina are recorded for the first time from Mexico and Micropleura sp. is the first American representative of the genus recorded outside South America. Findings of A. americanum, Telorchis sp., P. groschafti, D. helicina and Micropleura sp. in C. moreletii represent new host records. Some observations on the early development of D. helicina are provided. All species, except for P. recurvum, are briefly described and illustrated and some problems concerning their morphology, taxonomy and geographical distribution are discussed. PMID:11266135

  17. Hematologic and plasma biochemical reference intervals for Morelet's crocodiles (Crocodylus moreletii) in the northern wetlands of Campeche, Mexico.

    PubMed

    Padilla, Sergio E; Weber, Manuel; Jacobson, Elliott R

    2011-07-01

    Health surveys and hematologic and plasma biochemical analyses were conducted in 52 free-ranging and 51 captive Morelet's crocodiles (Crocodylus moreletii) in Campeche, Mexico, March-September 2007. Blood samples from 92 crocodiles (45 free-ranging and 47 captive) were collected for hematologic and plasma biochemical analyses. Average values of erythrocytes of free-ranging crocodiles were 1,046,166 cells/μl, and total white cells were 1.03 × 10(4) cells/μl. Captive crocodiles had erythrocyte and leukocyte values of 1,100,416 cells/μl and 8.51 × 10(3) cells/μl, respectively. There were no significant differences in values of erythrocytes or in hematocrit between free-ranging and captive crocodiles, or between sexes, or among size classes. Counts of leukocytes in free-ranging crocodiles were significantly higher than in captive individuals. The mean values of plasma analytes were 69.55 mg/l (glucose), 250.14 mg/l (cholesterol), 3.04 mg/l (uric acid), 2.70 mg/l (creatinine), and 20.20 IU/l (alanine aminotransferase). There were significant differences in cholesterol between free-ranging and captive crocodiles and between sexes. PMID:21719816

  18. Metals in the caudal scutes of Morelet's crocodile (Crocodylus moreletii) from the southern Gulf of Mexico.

    PubMed

    Trillanes, C E; Pérez-Jiménez, J C; Rosíles-Martínez, R; González-Jáuregui, M

    2014-10-01

    Caudal scutes were collected from 92 Morelet's crocodiles (Crocodylus moreletii) between May and August 2012, in three Wildlife Management and Use Units (UMAs, from its name in Spanish) and three wild sites in Campeche, Mexico. The UMAs are intensive, with an ex situ approach to manage crocodiles in captivity. The concentrations of arsenic, mercury, lead, nickel, cadmium and chromium were analyzed in each sample. As and Pb were detected in all samples, Hg in 86 and Ni in 74. The metal concentrations estimated were higher than most of the concentrations reported for skin, tail tip and caudal scutes in other crocodilians around the world. The concentration of As, Pb and Ni was significantly greater in the free-ranging groups than in the captive groups in UMAs (p < 0.05). Negative linear relationship was estimated between the snout-vent length and the concentration of Pb (in five groups) and Ni (in three groups). In this region C. moreletii is exposed to metals contamination and more studies are necessary to establish if represents a risk to their populations. PMID:25134925

  19. Morphology of the gular valve of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768).

    PubMed

    Putterill, J F; Soley, J T

    2006-08-01

    The morphology of the gular valve of the Nile crocodile was studied on the heads of eight 2.5-3-year-old commercially raised Nile crocodiles (Crocodylus niloticus). A description of the macroscopic and microscopic features of the gular valve is presented and the results are compared with published information on this species and other Crocodylia. The histological features are supplemented by information supplied by scanning electron microscopy (SEM). Anatomically, the dorsal and ventral components of the gular valve in the Nile crocodile form an efficient seal that effectively separates the oral and pharyngeal cavities consistent with the natural behavior and feeding habits of this animal. The gular valve is more complex in nature than superficial observations would suggest, with the dorsal and ventral folds being complemented by a series of smaller folds, particularly at the lateral fringes of the valve. Histologically, the surface epithelium of the valve demonstrates a transition from the typical stratified squamous epithelium of the oral cavity to that of the respiratory epithelium lining the pharyngeal cavity. The respiratory epithelium is characterized by the presence of ciliated cells and goblet cells and is accompanied by the appearance of large mucus-secreting glands in the underlying connective tissue. The transition between the two epithelial types is marked by the presence of a relatively prominent region where the stratified squamous epithelial cells undergo a gradual transformation into the typical elements of a respiratory epithelium. SEM graphically illustrated the extent of ciliation on both components of the gular valve as well as clearly defining the transition zones between the various types of surface epithelium present. No structures resembling taste receptors were observed in the mucosa of the gular valve. PMID:16634086

  20. Evaluating the effect of salinity on a simulated American Crocodile (Crocodylus acutus) population with applications to conservation and Everglades restoration

    USGS Publications Warehouse

    Richards, Paul M.; Mooij, Wolf M.; DeAngelis, Donald L.

    2004-01-01

    Everglades restoration will alter the hydrology of South Florida, affecting both water depth and salinity levels in the southern fringes of the Everglades, the habitat of the endangered American crocodile (Crocodylus acutus). A key question is what the effects of these hydrologic changes will be on the crocodile population. Reliable predictions of the viability of endangered species under a variety of management scenarios are of vital importance in conservation ecology. Juvenile American crocodiles are thought to be sensitive to high salinity levels, suffering reduced mass, and potentially reduced survivorship and recruitment. This could negatively impact the population recovery. We addressed the management issue of how the crocodile population will respond to alterations in hydrology with a spatially explicit individual-based model. The model is designed to relate water levels, salinities, and dominant vegetation to crocodile distribution, abundance, population growth, individual growth, survival, nesting effort, and nesting success. Our analysis shows that Everglades restoration, through its effects on water flow to estuaries, may benefit crocodile populations if increased freshwater flow reduces the chance that regional salinity levels exceed levels where small individuals lose mass. In addition, we conclude that conservation priority should be placed on reducing anthropogenic sources of mortality on large individuals, such as road mortality. Finally, research should focus on estimates of annual survivorship for large individuals.

  1. Population assessment of the American crocodile, Crocodylus acutus (Crocodilia: Crocodylidae) on the Pacific coast of Costa Rica.

    PubMed

    Mauger, Laurie A; Velez, Elizabeth; Cherkiss, Michael S; Brien, Matthew L; Boston, Michael; Mazzotti, Frank J; Spotila, James R

    2012-12-01

    The American crocodile, Crocodylus acutus, is widely distributed in the American neotropics. It is endangered throughout most of its range and is listed as vulnerable by the International Union for the Conservation of Natural Fauna and Flora (IUCN) and on Appendix I of the Convention for the International Trade in Endangered Species of Wild Flora and Fauna (CITES). Despite this listing, there are few published reports on population status throughout most of its range. We investigated the status of the C. acutus, at several locations along the Pacific coast of Costa Rica. We carried out spotlight and nesting surveys from 2007-2009 along the Costa Rican Pacific coast in four distinct areas, coastal areas of Las Baulas (N=40) and Santa Rosa (N=9) National Parks and the Osa Conservation Area (N=13), and upriver in Palo Verde National Park (N=11). We recorded crocodile locations and standard environmental data at each observation. Encounter rates, population structure, distribution within each area and data on successful nesting (presence of hatchlings, nests, etc) were determined. We attempted to capture all crocodiles to record standard morphometrics. A total of 586 crocodiles were observed along 185.8km of survey route. The majority of animals encountered (54.9%) were either hatchlings (<0.5m) or juveniles (0.5-1.25m). The average non-hatchling encounter rate per survey for the Pacific coast was 3.1 crocodiles/km, with individual encounter rates ranging from 1.2 crocodiles/km to 4.3 crocodiles/ km in Las Baulas National Park and the Osa Conservation Area respectively. Distribution of size classes within the individual locations did not differ with the exception of Santa Rosa and Las Baulas National Parks, where hatchlings were found in water with lower salinities. These were the first systematic surveys in several of the areas studied and additional work is needed to further characterize the American crocodile population in Costa Rica. PMID:23342536

  2. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles (Crocodylus niloticus) exposed to contaminants from the Crocodile River, South Africa.

    PubMed

    Arukwe, Augustine; Myburgh, Jan; Langberg, Håkon A; Adeogun, Aina O; Braa, Idunn Godal; Moeder, Monika; Schlenk, Daniel; Crago, Jordan Paul; Regoli, Francesco; Botha, Christo

    2016-04-01

    In the present study, the developmental (including fertility) and endocrine-disruptive effects in relation to chemical burden in male and female Nile crocodiles (Crocodylus niloticus), from a commercial crocodile farm in the Brits district, South Africa, exposed to various anthropogenic aquatic contaminants from the natural environment was investigated. Hepatic transcript levels for vitellogenin (Vtg), zona pellucida (ZP) and ERα (also in gonads) were analyzed using real-time PCR. Plasma estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were analyzed using enzyme immunoassay. Gonadal aromatase and hepatic testosterone metabolism (6β-hydroxylase (6β-OHase)) were analyzed using biochemical methods. Overall, there is high and abnormal number (%) of infertile and banded eggs during the studied reproductive seasons, showing up to 57 and 34% of infertile eggs in the 2009/2010 and 2013/2014 seasons, respectively. In addition, the percentage of banded eggs ranged between 10 and 19% during the period of 2009-2014 seasons. While hepatic ERα, Vtg, ZP mRNA and testosterone 6β-OHase, were equally expressed in female and male crocodiles, gonadal ERα mRNA and aromatase activity were significantly higher in females compared to male crocodiles. On the other hand, plasma T and 11-KT levels were significantly higher in males, compared to female crocodiles. Principal component analysis (PCA) produced significant grouping that revealed correlative relationships between reproductive/endocrine-disruptive variables and liver contaminant burden, that further relates to measured contaminants in the natural environment. The overall results suggest that these captive pre-slaughter farm crocodiles exhibited responses to anthropogenic aquatic contaminants with potentially relevant consequences on key reproductive and endocrine pathways and these responses may be established as relevant species endocrine disruptor biomarkers of exposure and effects in this threatened

  3. Molecular evidence for genetic distinctions between Chlamydiaceae detected in Siamese crocodiles (Crocodylus siamensis) and known Chlamydiaceae species.

    PubMed

    Sariya, Ladawan; Kladmanee, Kan; Bhusri, Benjaporn; Thaijongrak, Prawporn; Tonchiangsai, Kanittha; Chaichoun, Kridsada; Ratanakorn, Parntep

    2015-02-01

    Chlamydiosis, caused by Chlamydiaceae, is a zoonotic disease found in humans and several species of animals, including reptiles and amphibians. Although chlamydiosis in saltwater crocodiles has been previously reported in South Africa and Papua New Guinea, the reported strains have not been identified or confirmed. Therefore, the main aim of this study was to sequence and characterize Chamydiaceae isolated from Siamese crocodiles. Results showed the 16S ribosomal (r) RNA and the 16S/23S rRNA gene of the crocodile isolates were closely related to the genus Chlamydophila with matched identity greater than 98%. The phylogenetic tree constructed from the 16S/23S rRNA gene showed the crocodile cluster diverges far from Cp. caviae with a 100% bootstrap value. The tree based on the ompA gene loci distinguished the crocodile strains into genotypes I, II, and III. The present study is the first report on Chlamydophila detected in Siamese crocodiles that is genetically distinct from the known species of Chlamydiaceae. PMID:25854083

  4. Organochlorine contaminants in complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs from Belize.

    PubMed

    Wu, Ted H; Cañas, Jaclyn E; Rainwater, Thomas R; Platt, Steven G; McMurry, Scott T; Anderson, Todd A

    2006-11-01

    Seven complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs were collected in northern Belize and examined for organochlorine (OC) pesticide residues. The primary OC detected, p,p-DDE, was found in every egg analyzed (n=175). Other OCs detected included p,p-DDT, p,p-DDD, methoxychlor, aldrin, and endosulfan I. Concentrations of individual OCs ranged from 4 ppb (ng chemical/g egg wet weight) to greater than 500 ppb. A statistical evaluation of p,p-DDE levels in three complete clutches was used to derive the minimum number of eggs needed from a clutch to precisely determine the mean p,p-DDE concentration representative of that clutch. Sample sizes of 8 (80% confidence level) and 11 (90% confidence level) were determined to yield an accurate estimate of contaminant levels in a full clutch of eggs. The statistically recommended sample size of 11 eggs (at 90% confidence level) was successfully tested on the four additional clutches. PMID:16504356

  5. Bioactive compounds from crocodile (Crocodylus siamensis) white blood cells induced apoptotic cell death in hela cells.

    PubMed

    Patathananone, Supawadee; Thammasirirak, Sompong; Daduang, Jureerut; Chung, Jing Gung; Temsiripong, Yosapong; Daduang, Sakda

    2016-08-01

    Crocodile (Crocodylus siamensis) white blood cell extracts (WBCex) were examined for anticancer activity in HeLa cell lines using the MTT assay. The percentage viability of HeLa cells significantly deceased after treatment with WBCex in a dose- and time-dependent manner. The IC50 dose was suggested to be approximately 225 μg/mL protein. Apoptotic cell death occurred in a time-dependent manner based on investigation by flow cytometry using annexin V-FITC and PI staining. DAPI nucleic acid staining indicated increased chromatin condensation. Caspase-3, -8 and -9 activities also increased, suggesting the induction of the caspase-dependent apoptotic pathway. Furthermore, the mitochondrial membrane potential (ΔΨm ) of HeLa cells was lost as a result of increasing levels of Bax and reduced levels of Bcl-2, Bcl-XL, Bcl-Xs, and XIAP. The decreased ΔΨm led to the release of cytochrome c and the activation of caspase-9 and -3. Apoptosis-inducing factor translocated into the nuclei, and endonuclease G (Endo G) was released from the mitochondria. These results suggest that anticancer agents in WBCex can induce apoptosis in HeLa cells via both caspase-dependent and -independent pathways. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 986-997, 2016. PMID:25691005

  6. Age, fertility and reproductive behavior in cuban crocodiles, Crocodylus rhombifer, at the Smithsonian's National Zoological Park.

    PubMed

    Augustine, Lauren; Watkins, Barbara

    2015-01-01

    The Smithsonian's National Zoological Park (NZP) has a long history with Cuban crocodiles, Crocodylus rhombifer, beginning in 1900's when the first animals arrived at the NZP. Today, the Zoo has two breeding groups of C. rhombifer and has observed and analyzed reproductive behavior and fertility rates over the last three years. Fertility rates were determined initially by observing the formation of an opaque band that forms on the shell of a fertile egg, called banding. The fertility rates by banding were later compared to the observation made after opening the eggs to verify fertility. In addition to tracking fertility, nesting and agonistic behavior were also observed. Several notable observations were documented over the same period. These included a male predating a nesting female's eggs, increased aggression between two females housed together, the continued development of a partially banded egg, and the discovery of 19 additional egg shells post oviposition by both females in the enclosure. Here we discuss the nest phenology, fertility and behavior of the five exhibited C. rhombifer at the Smithsonian's National Zoological Park over a 3-year period. Zoo Biol. 34:278-284, 2015. © 2015 Wiley Periodicals Inc. PMID:25716550

  7. Development of transient head cavities during early organogenesis of the Nile Crocodile (Crocodylus niloticus).

    PubMed

    Kundrát, Martin; Janácek, Jirí; Martin, Samuel

    2009-09-01

    Three consecutive pairs of head cavities (premandibular, mandibular, and hyoid) found in elasmobranchs have been considered as remnants of preotic 'head' somites-serial homologues of the myotomic compartments of trunk somites that give rise to the extraoccular musculature. Here, we study a more derived vertebrate, and show that cavitation is more complex in the head of Crocodylus niloticus, than just the occurrence of three pairs of cavities. Apart from the premandibular cavities, paired satellite microcavities, and unpaired extrapremandibular microcavities are recognized in the prechordal region as well. We observed that several developmental phenomena occur at the same time as the formation of the head cavities (premandibular, satellite, extrapremandibular, mandibular, and hyoid) appear temporarily in the crocodile embryo. These are 1) rapid growth of the optic stalk and inflation of the optic vesicle; 2) release of the intimate topographical relationships between the neural tube, notochord and oral gut; 3) tendency of the prechordal mesenchyme to follow the curvature of the forebrain; and 4) proliferation of the prechordal mesenchyme. On the basis of volumetric characters, only the hyoid cavity and hyoid condensation is comparable to the trunk somitocoel and somite, respectively. PMID:19291672

  8. Comparison of the lipid properties of captive, healthy wild, and pansteatitis-affected wild Nile crocodiles (Crocodylus niloticus).

    PubMed

    Osthoff, Gernot; Hugo, Arno; Bouwman, Henk; Buss, Peter; Govender, Danny; Joubert, Chris C; Swarts, Jannie C

    2010-01-01

    The results presented describe and compare the fatty acid composition and melting properties of captive, healthy wild, and pansteatitis-affected wild crocodiles (Crocodylus niloticus). Differences in fatty acid composition between intramuscular and adipose fat is noted in captive crocodiles, and the latter differs from wild crocodiles as a result of different diets. Adipose fat of healthy wild crocodiles differs minimally from diseased ones, respectively with 37.3+/-2.6% vs. 43.2+/-2.3% monounsaturated fatty acids, and 43.2+/-2.9% in dead crocodiles, while polyunsaturated fatty acids decrease from 27.3+/-1.9% to as low as 21.9+/-3.6% respectively. Of the unsaturated fatty acids 18:2n-6 decreased from 6.5+/-2.6% in unaffected crocodiles to 3.5+/-0.6% in highly affected and 3.2+/-0.4% in dead crocodiles, and 22:5n-3 from 2.8+/-0.6% to 1.8+/-0.3% and 2.2+/-0.3% respectively. The melting properties as determined by differential scanning calorimetry show that extracted adipose fat is a small degree softer in pansteatitis-affected tissue, specifically in the temperature range 7-36 degrees C, and does not contribute to the hard texture noted for adipose fat tissue of pansteatitis-affected animals. A high moisture content of 51.0+/-19.7% of the fat tissue of pansteatitis-affected animals vs.17.1+/-8.0% of healthy ones, suggests that physiological changes due to interstitial inflammation may contribute to the hard texture. PMID:19800020

  9. Parent-offspring communication in the Nile crocodile Crocodylus niloticus: do newborns' calls show an individual signature?

    PubMed

    Vergne, Amélie L; Avril, Alexis; Martin, Samuel; Mathevon, Nicolas

    2007-01-01

    Young Nile crocodiles Crocodylus niloticus start to produce calls inside the egg and carry on emitting sounds after hatching. These vocalizations elicit maternal care and influence the behaviour of other juveniles. In order to investigate the acoustic structure of these calls, focusing on a possible individual signature, we have performed acoustic analyses on 400 calls from ten young crocodiles during the first 4 days after hatching. Calls have a complex acoustic structure and are strongly frequency modulated. We assessed the differences between the calls of the individuals. We found a weak individual signature. An individual call-based recognition of young by the mother is thus unlikely. In other respects, the call acoustic structure changes from the first to the fourth day after hatching: fundamental frequency progressively decreases. These modifications might provide important information to the mother about her offspring--age and size--allowing her to customize her protective care to best suit the needs of each individual. PMID:17106675

  10. Parent-offspring communication in the Nile crocodile Crocodylus niloticus: do newborns' calls show an individual signature?

    NASA Astrophysics Data System (ADS)

    Vergne, Amélie L.; Avril, Alexis; Martin, Samuel; Mathevon, Nicolas

    2007-01-01

    Young Nile crocodiles Crocodylus niloticus start to produce calls inside the egg and carry on emitting sounds after hatching. These vocalizations elicit maternal care and influence the behaviour of other juveniles. In order to investigate the acoustic structure of these calls, focusing on a possible individual signature, we have performed acoustic analyses on 400 calls from ten young crocodiles during the first 4 days after hatching. Calls have a complex acoustic structure and are strongly frequency modulated. We assessed the differences between the calls of the individuals. We found a weak individual signature. An individual call-based recognition of young by the mother is thus unlikely. In other respects, the call acoustic structure changes from the first to the fourth day after hatching: fundamental frequency progressively decreases. These modifications might provide important information to the mother about her offspring—age and size—allowing her to customize her protective care to best suit the needs of each individual.

  11. Autoinduction, purification, and characterization of soluble α-globin chains of crocodile (Crocodylus siamensis) hemoglobin in Escherichia coli.

    PubMed

    Kabbua, Thai; Anwised, Preeyanan; Boonmee, Atcha; Subedi, Bishnu P; Pierce, Brad S; Thammasirirak, Sompong

    2014-11-01

    We have established a method to express soluble heme-bound recombinant crocodile (Crocodylus siamensis) α-globin chain holo-protein in bacteria (Escherichia coli) using an autoinduction system without addition of exogenous heme. This is the first time that heme-bound crocodile α-globin chains have been expressed in bacteria without in vitro heme reconstitution. The observed molecular mass of purified recombinant α-globin is consistent with that calculated from the primary amino acid sequence of native crocodile (C. siamensis) α-globin. Both the monomeric and the dimeric protein configuration formed by intermolecular disulfide bond could be purified as soluble protein. Spectroscopic characterization [UV-visible, circular dichroism (CD), and electron paramagnetic resonance (EPR)] of purified recombinant α-globin demonstrates nearly identical properties as reported for hemoglobin and myoglobin isolated from other organisms. For comparison, cyanide and nitric oxide binding of purified α-globin was also investigated. These results suggested that C. siamensis α-globin expressed in E. coli was folded correctly with proper incorporation of the heme cofactor. The expression method we now describe can facilitate production and isolation of individual globin chains in order to further study the mechanism and assembly of crocodile hemoglobin. PMID:25175288

  12. Fine scale patterns of genetic partitioning in the rediscovered African crocodile, Crocodylus suchus (Saint-Hilaire 1807)

    PubMed Central

    Shirley, Matthew H.; Hekkala, Evon R.

    2016-01-01

    Landscape heterogeneity, phylogenetic history, and stochasticity all influence patterns of geneflow and connectivity in wild vertebrates. Fine-scale patterns of genetic partitioning may be particularly important for the sustainable management of widespread species in trade, such as crocodiles. We examined genetic variation within the rediscovered African crocodile, Crocodylus suchus, across its distribution in West and Central Africa. We genotyped 109 individuals at nine microsatellite loci from 16 sampling localities and used three Bayesian clustering techniques and an analysis of contemporary gene flow to identify population structure across the landscape. We identified up to eight genetic clusters that largely correspond to populations isolated in coastal wetland systems and across large distances. Crocodile population clusters from the interior were readily distinguished from coastal areas, which were further subdivided by distance and drainage basin. Migration analyses indicated contemporary migration only between closely positioned coastal populations. These findings indicate high levels of population structure throughout the range of C. suchus and we use our results to suggest a role for molecular tools in identifying crocodile conservation units for this species. Further research, including additional sampling throughout the Congo and Niger drainages, would clarify both the landscape connectivity and management of this species. PMID:27114867

  13. Fine scale patterns of genetic partitioning in the rediscovered African crocodile, Crocodylus suchus (Saint-Hilaire 1807).

    PubMed

    Cunningham, Seth W; Shirley, Matthew H; Hekkala, Evon R

    2016-01-01

    Landscape heterogeneity, phylogenetic history, and stochasticity all influence patterns of geneflow and connectivity in wild vertebrates. Fine-scale patterns of genetic partitioning may be particularly important for the sustainable management of widespread species in trade, such as crocodiles. We examined genetic variation within the rediscovered African crocodile, Crocodylus suchus, across its distribution in West and Central Africa. We genotyped 109 individuals at nine microsatellite loci from 16 sampling localities and used three Bayesian clustering techniques and an analysis of contemporary gene flow to identify population structure across the landscape. We identified up to eight genetic clusters that largely correspond to populations isolated in coastal wetland systems and across large distances. Crocodile population clusters from the interior were readily distinguished from coastal areas, which were further subdivided by distance and drainage basin. Migration analyses indicated contemporary migration only between closely positioned coastal populations. These findings indicate high levels of population structure throughout the range of C. suchus and we use our results to suggest a role for molecular tools in identifying crocodile conservation units for this species. Further research, including additional sampling throughout the Congo and Niger drainages, would clarify both the landscape connectivity and management of this species. PMID:27114867

  14. Critical Comment: On the morphology and taxonomy of Griphoibilharizia amoena Platt and Blair, 1991 (Schistosomatoidea), a dioecious digenetic trematode parasite of the freshwater crocodile, Crocodylus johnstoni, in Australia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Griphobilharzia amoena Platt and Blair, 1991, was originally described as a dioecious trematode parasitic in the circulatory system of the Australian freshwater crocodile, Crocodylus johnsoni, with the female completely enclosed in a gynecophoric chamber of the male and the 2 worms oriented anti-par...

  15. Identification and partial sequencing of a crocodile poxvirus associated with deeply penetrating skin lesions in farmed Nile crocodiles, Crocodylus niloticus.

    PubMed

    Huchzermeyer, F W; Wallace, D B; Putterill, J F; Gerdes, G H

    2009-09-01

    When large numbers of crocodile skins were downgraded because of the presence of small pin prick-like holes, collapsed epidermal cysts were found deep in the dermis of juvenile crocodiles while forming cysts were observed in hatchlings. Histopathology of these forming cysts showed the presence of intracytoplasmic inclusions in proliferating and ballooning epidermal cells. Pox virions were seen in electron microscope preparations made from the scabs of such early lesions. The partial sequencing of virus material from scrapings of these lesions and comparison of it with the published sequence of crocodile poxvirus showed the virus associated with the deep lesions to be closely related, but different. To differentiate between the two forms of crocodile pox infection it is suggested that the previously known form should be called "classical crocodile pox" and the newly discovered form "atypical crocodile pox". The application of strict hygiene measures brought about a decline in the percentage of downgraded skins. PMID:21105598

  16. Distribution patterns and predilection muscles of Trichinella zimbabwensis larvae in experimentally infected Nile crocodiles (Crocodylus niloticus Laurenti).

    PubMed

    La Grange, Louis J; Mukaratirwa, Samson

    2014-01-01

    No controlled studies have been conducted to determine the predilection muscles of Trichinella zimbabwensis larvae in Nile crocodiles (Crocodylus niloticus) or the influence of infection intensity on the distribution of the larvae in crocodiles. The distribution of larvae in muscles of naturally infected Nile crocodiles and experimentally infected caimans (Caiman crocodilus) and varans (Varanus exanthematicus) have been reported in literature. To determine the distribution patterns of T. zimbabwensis larvae and predilection muscles, 15 crocodiles were randomly divided into three cohorts of five animals each, representing high infection (642 larvae/kg of bodyweight average), medium infection (414 larvae/kg of bodyweight average) and low infection (134 larvae/kg of bodyweight average) cohorts. In the high infection cohort, high percentages of larvae were observed in the triceps muscles (26%) and hind limb muscles (13%). In the medium infection cohort, high percentages of larvae were found in the triceps muscles (50%), sternomastoid (18%) and hind limb muscles (13%). In the low infection cohort, larvae were mainly found in the intercostal muscles (36%), longissimus complex (27%), forelimb muscles (20%) and hind limb muscles (10%). Predilection muscles in the high and medium infection cohorts were similar to those reported in naturally infected crocodiles despite changes in infection intensity. The high infection cohort had significantly higher numbers of larvae in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles (p < 0.05) compared with the medium infection cohort. In comparison with the low infection cohort, the high infection cohort harboured significantly higher numbers of larvae in all muscles (p < 0.05) except for the tongue. The high infection cohort harboured significantly higher numbers of larvae (p < 0.05) in the sternomastoid, triceps, intercostal, longissimus complex

  17. General morphology of the oral cavity of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768). I. Palate and gingivae.

    PubMed

    Putterill, J F; Soley, J T

    2003-12-01

    The heads of nine 2.5 to 3-year-old Nile crocodiles (Crocodylus niloticus) were obtained from a commercial farm where crocodiles are raised for their skins and meat. The animals from which these specimens originated were clinically healthy at the time they were slaughtered. A detailed description of the macroscopic and microscopic features of the palate and gingivae of the Nile crocodile is presented and the results are compared with published information on this species and other Crocodylia. The histological features are supplemented by information supplied by scanning electron microscopy. Macroscopic features of interest are the small conical process situated at the base of the first two incisors of the maxilla, the distribution of cobbled units on the palate, and the broad dentary shelf forming the rostral aspect of the mandible. Histologically the palate and gingivae did not differ significantly from each other and both regions showed a presence of Pacinian-type corpuscles. Two types of sensory structures (taste receptors and pressure receptors) were identified in the regions examined, both involving modification of the epithelium and the underlying connective tissue. PMID:14971731

  18. Prevalence and serovar distribution of Salmonella in fresh and frozen meat from captive Nile crocodiles (Crocodylus niloticus).

    PubMed

    Madsen, M

    1996-02-01

    Salmonella was isolated from 6 of 20 (30.0%) samples of fresh meat, and from 28 of 140 (20.0%) samples of frozen meat processed for human consumption from captive Nile crocodiles (Crocodylus niloticus) in Zimbabwe. Salmonella enterica isolates showed a serovar distribution of 41.2% (14/34) subsp. enterica, 11.8% (4/34) subsp. salamae and 41.2% (14/34) subsp. diarizonae. Analyses of fresh meat samples yielded Aeromonas (A. hydrophila) in 18 of 20 samples (90%), and a mean aerobic plate count (APC, 30 degrees C) of 5.79 cfu/g, a mean coliform count (TC, 37 degrees C) of 5.08 cfu/g and a mean faecal coliform count FC, 44 degrees C) of 4.76 cfu/g. It is suggested that the presence of Salmonella in meat samples may be due to skin surface contamination originating from faecally polluted rearing water ponds combined with excessive handling procedures during flaying. The common presence of Salmonella, including serovars of proven pathogenic potential, in crocodile meat offered for human consumption should concern consumers and public health authorities, as well as staff employed at crocodile farms. PMID:8722192

  19. Capture of farmed Nile crocodiles (Crocodylus niloticus): comparison of physiological parameters after manual capture and after capture with electrical stunning.

    PubMed

    Pfitzer, S; Ganswindt, A; Fosgate, G T; Botha, P J; Myburgh, J G

    2014-09-27

    The electric stunner (e-stunner) is commonly used to handle Nile crocodiles (Crocodylus niloticus) on commercial farms in South Africa, but while it seems to improve handling and safety for the keepers, no information regarding physiological reactions to e-stunning is currently available. The aim of this study was therefore to compare various physiological parameters in farmed C niloticus captured either manually (noosing) or by using an e-stunner. A total of 45 crocodiles were captured at a South African farm by either e-stunning or noosing, and blood samples were taken immediately as well as four hours after capture. Parameters monitored were serum corticosterone, lactate, glucose, as well as alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase and creatine kinase. Lactate concentrations were significantly higher in noosed compared with e-stunned animals (P<0.001). No other blood parameter differed significantly between the two methods of capture. In addition, recorded capture time confirmed that noosing takes significantly longer time compared with e-stunning (P<0.001), overall indicating that e-stunning seems to be the better option for restraint of especially large numbers of crocodiles in a commercial setup because it is quicker, safer and did not cause a significant increase in any of the parameters measured. PMID:25096588

  20. General morphology of the oral cavity of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768). II. The tongue.

    PubMed

    Putterill, J F; Soley, J T

    2004-12-01

    The heads of nine 2.5 to 3-year-old Nile crocodiles (Crocodylus niloticus) were obtained from a commercial farm where crocodiles are raised for their skins and meat. The animals from which these specimens were obtained appeared clinically healthy at the time they were slaughtered. A description of the macroscopic and microscopic features of the tongue of the Nile crocodile is presented and the results are compared with published information on this species and other Crocodylia. The histological features are supplemented by information supplied by scanning electron microscopy. Macroscopic features of interest were the dome shaped structures grouped in a triangular formation on the posterior two-thirds of the dorsum of the tongue. These structures were identified by light microscopy to contain well-developed branched, coiled tubular glands and associated lymphoid tissue. Other histological features included a lightly keratinised stratified squamous surface epithelium supported by a thick layer of irregular dense fibrous connective tissue. Deep to this region was a clearly demarcated adipose tissue core with a dense mass of striated lingual musculature. Localised thickenings were present in the epithelium which were associated with ellipsoid intra-epithelial structures resembling taste buds. PMID:15732453

  1. Pansteatitis of unknown etiology associated with large-scale Nile crocodile (Crocodylus niloticus) mortality in Kruger National Park, South Africa: pathologic findings.

    PubMed

    Lane, Emily P; Huchzermeyer, Fritz W; Govender, Danny; Bengis, Roy G; Buss, Peter E; Hofmeyr, Markus; Myburgh, Jan G; Steyl, Johan C A; Pienaar, Daniel J; Kotze, Antoinette

    2013-12-01

    Annual mortality events in Nile crocodiles (Crocodylus niloticus) in the Olifants River Gorge in Kruger National Park, South Africa, were experienced between 2008 and 2012, during which at least 216 crocodiles died. Live crocodiles were lethargic. Necropsy examination of 56 affected crocodiles showed dark yellow-brown firm nodules in both somatic fat and the abdominal fat body. In all of the 11 crocodiles submitted for histology, degenerative, necrotic, and inflammatory changes supported a diagnosis of steatitis in both fat types. Crocodiles are apex predators in this anthropogenically changed aquatic ecosystem that is used by humans upstream and downstream from the park for domestic, agricultural, fishing, and recreational purposes. This pathologic review of pansteatitis in crocodiles in the Olifants River system was part of a broad multidisciplinary research program. To date, no definitive causative agent has been identified. Epidemiologic evidence suggests that this event may have been a one-time event with long-standing repercussions on the health of the crocodiles. Pathologic findings are rarely documented in wild crocodilians. This study also reports on other conditions, including the presence of coccidian oocysts, capillarid and filaroid nematodes, digenetic trematodes, and pentastomes. PMID:24450048

  2. Normal intestinal flora of wild Nile crocodiles (Crocodylus niloticus) in the Okavango Delta, Botswana.

    PubMed

    Lovely, C J; Leslie, A J

    2008-06-01

    Bacterial and fungal cultures were performed from cloacal swabs collected from 29 wild Nile crocodiles, captured in the Okavango Delta, Botswana. Sixteen species of bacteria and 6 fungal species were cultured. Individual crocodiles yielded 1-4 bacterial species, and 0-2 fungal species. The most commonly isolated bacteria were Microbacterium, Enterococcus faecalis, Aeromonas hydrophila, and Escherichia coli. No salmonellae were cultured. The most commonly occurring fungus was Cladosporium. Several of the bacterial and fungal species isolated have been implicated in cases of septicaemia in crocodilians. Knowledge of the normal intestinal flora will contribute towards the development of a crocodile-specific probiotic for use in farmed crocodiles. PMID:18846850

  3. Trichinella zimbabwensis in wild Nile crocodiles (Crocodylus niloticus) of South Africa.

    PubMed

    La Grange, Louis J; Marucci, Gianluca; Pozio, Edoardo

    2009-04-01

    Recent discovery of Trichinella zimbabwensis in crocodiles from Zimbabwe, Lake Cahora Basa, Mozambique, and from lake Abaja, Ethiopia, prompted strict control measures to curb the possible spread of the infection to humans and also to prevent its introduction to other countries, which were considered free of this pathogen. In 2006, the Chief Directorate Veterinary Services of Mpumalanga Province of South Africa launched a survey to investigate the status of wild and commercial breeding crocodiles in the province. To evaluate if T. zimbabwensis was circulating in the environments where crocodiles are living in South Africa, 9 fish, 36 reptiles (including 27 Nile crocodiles) and 4 mammals have been investigated to detect Trichinella sp. larvae in their muscles. In January 2008, a Nile crocodile from Komatipoort, sampled by means of a tail biopsy, tested positive for Trichinella larvae. In June-July 2008, Trichinella sp. larvae were also detected in four other Nile crocodiles from the Olifants River Gorge. The prevalence of Trichinella infection in the investigated wild Nile crocodiles from South Africa is 38.5%. The larvae were identified as belonging to T. zimbabwensis by multiplex-PCR. These are the first reports of T. zimbabwensis in South Africa and suggest that the distribution area of this parasite species is wider than that believed in the past. PMID:19167165

  4. The Relationship between Early Growth and Survival of Hatchling Saltwater Crocodiles (Crocodylus porosus) in Captivity

    PubMed Central

    Brien, Matthew L.; Webb, Grahame J.; McGuinness, Keith; Christian, Keith A.

    2014-01-01

    Hatchling fitness in crocodilians is affected by “runtism” or failure to thrive syndrome (FTT) in captivity. In this study, 300 hatchling C. porosus, artificially incubated at 32°C for most of their embryonic development, were raised in semi-controlled conditions, with growth criteria derived for the early detection of FTT (within 24 days). Body mass, four days after hatching (BM4d), was correlated with egg size and was highly clutch specific, while snout-vent length (SVL4d) was much more variable within and between clutches. For the majority of hatchlings growth trajectories within the first 24 days continued to 90 days and could be used to predict FTT affliction up to 300 days, highlighting the importance of early growth. Growth and survival of hatchling C. porosus in captivity was not influenced by initial size (BM4d), with a slight tendency for smaller hatchlings to grow faster in the immediate post-hatching period. Strong clutch effects (12 clutches) on affliction with FTT were apparent, but could not be explained by measured clutch variables or other factors. Among individuals not afflicted by FTT (N = 245), mean growth was highly clutch specific, and the variation could be explained by an interaction between clutch and season. FTT affliction was 2.5 times higher among clutches (N = 7) that hatched later in the year when mean minimum air temperatures were lower, compared with those clutches (N = 5) that hatched early in the year. The results of this study highlight the importance of early growth in hatchling C. porosus, which has implications for the captive management of this species. PMID:24960026

  5. The relationship between early growth and survival of hatchling saltwater crocodiles (Crocodylus porosus) in captivity.

    PubMed

    Brien, Matthew L; Webb, Grahame J; McGuinness, Keith; Christian, Keith A

    2014-01-01

    Hatchling fitness in crocodilians is affected by "runtism" or failure to thrive syndrome (FTT) in captivity. In this study, 300 hatchling C. porosus, artificially incubated at 32°C for most of their embryonic development, were raised in semi-controlled conditions, with growth criteria derived for the early detection of FTT (within 24 days). Body mass, four days after hatching (BM4d), was correlated with egg size and was highly clutch specific, while snout-vent length (SVL4d) was much more variable within and between clutches. For the majority of hatchlings growth trajectories within the first 24 days continued to 90 days and could be used to predict FTT affliction up to 300 days, highlighting the importance of early growth. Growth and survival of hatchling C. porosus in captivity was not influenced by initial size (BM4d), with a slight tendency for smaller hatchlings to grow faster in the immediate post-hatching period. Strong clutch effects (12 clutches) on affliction with FTT were apparent, but could not be explained by measured clutch variables or other factors. Among individuals not afflicted by FTT (N = 245), mean growth was highly clutch specific, and the variation could be explained by an interaction between clutch and season. FTT affliction was 2.5 times higher among clutches (N = 7) that hatched later in the year when mean minimum air temperatures were lower, compared with those clutches (N = 5) that hatched early in the year. The results of this study highlight the importance of early growth in hatchling C. porosus, which has implications for the captive management of this species. PMID:24960026

  6. Complete amino acid sequence of globin chains and biological activity of fragmented crocodile hemoglobin (Crocodylus siamensis).

    PubMed

    Srihongthong, Saowaluck; Pakdeesuwan, Anawat; Daduang, Sakda; Araki, Tomohiro; Dhiravisit, Apisak; Thammasirirak, Sompong

    2012-08-01

    Hemoglobin, α-chain, β-chain and fragmented hemoglobin of Crocodylus siamensis demonstrated both antibacterial and antioxidant activities. Antibacterial and antioxidant properties of the hemoglobin did not depend on the heme structure but could result from the compositions of amino acid residues and structures present in their primary structure. Furthermore, thirteen purified active peptides were obtained by RP-HPLC analyses, corresponding to fragments in the α-globin chain and the β-globin chain which are mostly located at the N-terminal and C-terminal parts. These active peptides operate on the bacterial cell membrane. The globin chains of Crocodylus siamensis showed similar amino acids to the sequences of Crocodylus niloticus. The novel amino acid substitutions of α-chain and β-chain are not associated with the heme binding site or the bicarbonate ion binding site, but could be important through their interactions with membranes of bacteria. PMID:22648692

  7. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus).

    PubMed

    Rodgers, Essie M; Schwartz, Jonathon J; Franklin, Craig E

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of 'fright-dive' capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; 'moderate' climate warming, 31.5°C; 'high' climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q 10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28-35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained 'fright-dive' performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  8. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus)

    PubMed Central

    Rodgers, Essie M.; Schwartz, Jonathon J.; Franklin, Craig E.

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of ‘fright-dive’ capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; ‘moderate’ climate warming, 31.5°C; ‘high’ climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28–35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained ‘fright-dive’ performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  9. Molecular cloning and characterization of Siamese crocodile (Crocodylus siamensis) copper, zinc superoxide dismutase (CSI-Cu,Zn-SOD) gene.

    PubMed

    Sujiwattanarat, Penporn; Pongsanarakul, Parinya; Temsiripong, Yosapong; Temsiripong, Theeranan; Thawornkuno, Charin; Uno, Yoshinobu; Unajak, Sasimanas; Matsuda, Yoichi; Choowongkomon, Kiattawee; Srikulnath, Kornsorn

    2016-01-01

    Superoxide dismutase (SOD, EC 1.15.1.1) is an antioxidant enzyme found in all living cells. It regulates oxidative stress by breaking down superoxide radicals to oxygen and hydrogen peroxide. A gene coding for Cu,Zn-SOD was cloned and characterized from Siamese crocodile (Crocodylus siamensis; CSI). The full-length expressed sequence tag (EST) of this Cu,Zn-SOD gene (designated as CSI-Cu,Zn-SOD) contained 462bp encoding a protein of 154 amino acids without signal peptides, indicated as intracellular CSI-Cu,Zn-SOD. This agreed with the results from the phylogenetic tree, which indicated that CSI-Cu,Zn-SOD belonged to the intracellular Cu,Zn-SOD. Chromosomal location determined that the CSI-Cu,Zn-SOD was localized to the proximal region of the Siamese crocodile chromosome 1p. Several highly conserved motifs, two conserved signature sequences (GFHVHEFGDNT and GNAGGRLACGVI), and conserved amino acid residues for binding copper and zinc (His(47), His(49), His(64), His(72), His(81), Asp(84), and His(120)) were also identified in CSI-Cu,Zn-SOD. Real-time PCR analysis showed that CSI-Cu,Zn-SOD mRNA was expressed in all the tissues examined (liver, pancreas, lung, kidney, heart, and whole blood), which suggests a constitutively expressed gene in these tissues. Expression of the gene in Escherichia coli cells followed by purification yielded a recombinant CSI-Cu,Zn-SOD, with Km and Vmax values of 6.075mM xanthine and 1.4×10(-3)mmolmin(-1)mg(-1), respectively. This Vmax value was 40 times lower than native Cu,Zn-SOD (56×10(-3)mmolmin(-1)mg(-1)), extracted from crocodile erythrocytes. This suggests that cofactors, protein folding properties, or post-translational modifications were lost during the protein purification process, leading to a reduction in the rate of enzyme activity in bacterial expression of CSI-Cu,Zn-SOD. PMID:26523498

  10. Effects of recombinant human growth hormone on anorexic Nile crocodiles (Crocodylus niloticus).

    PubMed

    Kimwele, C N; Kanui, T I; Aulie, A

    1992-07-01

    1. Eleven-month-old Nile crocodiles with poor appetite and retarded growth were injected with 0.325 micrograms/g recombinant human growth hormone (hGH) twice a week for 4 weeks. 2. The treated animals had a mean intake per meal of 29.8 g/kg, while the controls ate only 2.8 g/kg. 3. The treated group gained 8.1% of their initial body weight, while the controls lost 6.3%. 4. During 4 weeks of treatment the body and head length increased by 3.93 and 1.29%, respectively, while no linear growth took place in the controls. 5. The treated group had higher contents of skeletal muscle protein and liver glycogen than the control group. 6. In conclusion, recombinant hGH induces appetite and growth in anorexic crocodiles. PMID:1359943

  11. Gastric nematodes of nile crocodiles, Crocodylus niloticus Laurenti, 1768, in the Okavango River, Botswana.

    PubMed

    Junker, K; Wallace, K; Leslie, A J; Boomker, J

    2006-06-01

    The ascaridoid nematodes Dujardinascaris madagascariensis Chabaud & Caballero, 1966, Dujardinascaris dujardini (Travassos, 1920), Gedoelstascaris vandenbrandeni (Baylis, 1929) Sprent, 1978 and Multicaecum agile (Wedl, 1861) Baylis, 1923 were recovered from the stomach contents of Crocodylus niloticus Laurenti, 1768 from the Okavango River, Botswana, together with Eustrongylides sp., a dioctophymatoid nematode usually parasitizing piscivorous birds. Dujardinascaris madagascariensis was present in most of the infected hosts, while the remaining species were mostly represented in single collections in one to three hosts. All four ascaridoid nematodes represent new geographic records. PMID:16958261

  12. Biotransformation and Oxidative Stress Responses in Captive Nile Crocodile (Crocodylus niloticus) Exposed to Organic Contaminants from the Natural Environment in South Africa.

    PubMed

    Arukwe, Augustine; Røsbak, Randi; Adeogun, Aina O; Langberg, Håkon A; Venter, Annette; Myburgh, Jan; Botha, Christo; Benedetti, Maura; Regoli, Francesco

    2015-01-01

    In the present study, the biotransformation and oxidative stress responses in relation to chemical burden in the liver of male and female Nile crocodiles--Crocodylus niloticus--from a commercial crocodile farm passively exposed to various anthropogenic aquatic pollutants was investigated. In general, the data showed that male crocodiles consistently produced higher biotransformation and oxidative stress responses compared to females. Relationships between these responses and concentrations of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were also observed. Specifically, the catalytic assays for EROD and BROD (not PROD and MROD) showed sex-differences between male and female crocodiles and paralleled immunochemically determined CYP1A and CYP3A protein levels; the relatively similar levels of PAHs in both sexes suggest an estrogen-mediated reduction of this pathway in females. The antioxidant system exhibited higher levels in male crocodiles with slight or significant higher values for catalase (CAT), glutathione reductase (GR), glutathione peroxidases-H2O2 (GPx-H2O2), glutathione peroxidases-Cu (GPx-Cu), total antioxidant capacity towards peroxyl radicals (TOSC-ROO) and hydroxyl radicals (TOSC-HO), total glutathione (GSH) and malondialdehyde (MDA). On the other hand, the activities of acyl-CoA oxidase (AOX) and glutathione S-transferases (GST) were significantly higher in females. Principal component analysis (PCA) produced significant groupings that revealed correlative relationships (both positive and negative) between biotransformation/oxidative stress variables and liver PAHs and aliphatic hydrocarbon burden. The overall results suggest that these captive pre-slaughter crocodiles exhibited adverse exposure responses to anthropogenic aquatic contaminants with potentially relevant effects on key cellular pathways, and these responses may be established as relevant species biomarkers of exposure and effects in this endangered species. PMID

  13. GnRH-immunoreactive centrifugal visual fibers in the Nile crocodile (Crocodylus niloticus).

    PubMed

    Médina, Monique; Repérant, Jacques; Miceli, Dom; Ward, Roger; Arckens, Lutgarde

    2005-08-01

    Thin varicose centrifugal visual fibers, between 30-45 in number and displaying cGnRH-I immunoreactivity, were identified in Crocodylus niloticus. Approximately 80% of these fibers were also FMRF-amide-like immunoreactive. The cGnRH-I fibers extended from the preoptic region to the retina where they appeared to terminate in the external portion of the inner plexiform layer. The location of their neurons of origin could not be determined precisely following the intraocular injection of the retrograde axonal tracer RITC. Nevertheless, the presence of cGnRH-I-immunoreactive neurons exclusively within the complex comprising the terminal nerve and the septo-preoptic region, and of several retinopetal fibers labelled retrogradely with the axonal tracer at the septo-preoptic junction, indicates that the cGnRH-immunoreactive centrifugal visual system originates from within this complex. PMID:16002052

  14. Mitochondrial DNA analysis reveals hidden genetic diversity in captive populations of the threatened American crocodile (Crocodylus acutus) in Colombia.

    PubMed

    Bloor, Paul; Ibáñez, Carolina; Viloria-Lagares, Thomas A

    2015-01-01

    Identification of units within species worthy of separate management consideration is an important area within conservation. Mitochondrial DNA (mtDNA) surveys can potentially contribute to this by identifying phylogenetic and population structure below the species level. The American crocodile (Crocodylus acutus) is broadly distributed throughout the Neotropics. Its numbers have been reduced severely with the species threatened throughout much of its distribution. In Colombia, the release of individuals from commercial captive populations has emerged as a possible conservation strategy that could contribute to species recovery. However, no studies have addressed levels of genetic differentiation or diversity within C. acutus in Colombia, thus complicating conservation and management decisions. Here, sequence variation was studied in mtDNA cytochrome b and cytochrome oxidase I gene sequences in three Colombian captive populations of C. acutus. Two distinct lineages were identified: C. acutus-I, corresponding to haplotypes from Colombia and closely related Central American haplotypes; and C. acutus-II, corresponding to all remaining haplotypes from Colombia. Comparison with findings from other studies indicates the presence of a single "northern" lineage (corresponding to C. acutus-I) distributed from North America (southern Florida), through Central America and into northern South America. The absence of C. acutus-II haplotypes from North and Central America indicates that the C. acutus-II lineage probably represents a separate South American lineage. There appears to be sufficient divergence between lineages to suggest that they could represent two distinct evolutionary units. We suggest that this differentiation needs to be recognized for conservation purposes because it clearly contributes to the overall genetic diversity of the species. All Colombian captive populations included in this study contained a mixture of representatives of both lineages. As such

  15. An experimental and morphometric test of the relationship between vertebral morphology and joint stiffness in Nile crocodiles (Crocodylus niloticus).

    PubMed

    Molnar, Julia L; Pierce, Stephanie E; Hutchinson, John R

    2014-03-01

    Despite their semi-aquatic mode of life, modern crocodylians use a wide range of terrestrial locomotor behaviours, including asymmetrical gaits otherwise only found in mammals. The key to these diverse abilities may lie in the axial skeleton. Correlations between vertebral morphology and both intervertebral joint stiffness and locomotor behaviour have been found in other animals, but the vertebral mechanics of crocodylians have not yet been experimentally and quantitatively tested. We measured the passive mechanics and morphology of the thoracolumbar vertebral column in Crocodylus niloticus in order to validate a method to infer intervertebral joint stiffness based on morphology. Passive stiffness of eight thoracic and lumbar joints was tested in dorsal extension, ventral flexion and mediolateral flexion using cadaveric specimens. Fifteen measurements that we deemed to be potential correlates of stiffness were taken from each vertebra and statistically tested for correlation with joint stiffness. We found that the vertebral column of C. niloticus is stiffer in dorsoventral flexion than in lateral flexion and, in contrast to that of many mammals, shows an increase in joint stiffness in the lumbar region. Our findings suggest that the role of the axial column in crocodylian locomotion may be functionally different from that in mammals, even during analogous gaits. A moderate proportion of variation in joint stiffness (R(2)=0.279-0.520) was predicted by centrum width and height, neural spine angle and lamina width. These results support the possible utility of some vertebral morphometrics in predicting mechanical properties of the vertebral column in crocodiles, which also should be useful for forming functional hypotheses of axial motion during locomotion in extinct archosaurs. PMID:24574389

  16. Mitochondrial DNA analysis reveals hidden genetic diversity in captive populations of the threatened American crocodile (Crocodylus acutus) in Colombia

    PubMed Central

    Bloor, Paul; Ibáñez, Carolina; Viloria-Lagares, Thomas A

    2015-01-01

    Identification of units within species worthy of separate management consideration is an important area within conservation. Mitochondrial DNA (mtDNA) surveys can potentially contribute to this by identifying phylogenetic and population structure below the species level. The American crocodile (Crocodylus acutus) is broadly distributed throughout the Neotropics. Its numbers have been reduced severely with the species threatened throughout much of its distribution. In Colombia, the release of individuals from commercial captive populations has emerged as a possible conservation strategy that could contribute to species recovery. However, no studies have addressed levels of genetic differentiation or diversity within C. acutus in Colombia, thus complicating conservation and management decisions. Here, sequence variation was studied in mtDNA cytochrome b and cytochrome oxidase I gene sequences in three Colombian captive populations of C. acutus. Two distinct lineages were identified: C. acutus-I, corresponding to haplotypes from Colombia and closely related Central American haplotypes; and C. acutus-II, corresponding to all remaining haplotypes from Colombia. Comparison with findings from other studies indicates the presence of a single “northern” lineage (corresponding to C. acutus-I) distributed from North America (southern Florida), through Central America and into northern South America. The absence of C. acutus-II haplotypes from North and Central America indicates that the C. acutus-II lineage probably represents a separate South American lineage. There appears to be sufficient divergence between lineages to suggest that they could represent two distinct evolutionary units. We suggest that this differentiation needs to be recognized for conservation purposes because it clearly contributes to the overall genetic diversity of the species. All Colombian captive populations included in this study contained a mixture of representatives of both lineages. As

  17. Biotransformation and Oxidative Stress Responses in Captive Nile Crocodile (Crocodylus niloticus) Exposed to Organic Contaminants from the Natural Environment in South Africa

    PubMed Central

    Arukwe, Augustine; Røsbak, Randi; Adeogun, Aina O.; Langberg, Håkon A.; Venter, Annette; Myburgh, Jan; Botha, Christo; Benedetti, Maura; Regoli, Francesco

    2015-01-01

    In the present study, the biotransformation and oxidative stress responses in relation to chemical burden in the liver of male and female Nile crocodiles—Crocodylus niloticus—from a commercial crocodile farm passively exposed to various anthropogenic aquatic pollutants was investigated. In general, the data showed that male crocodiles consistently produced higher biotransformation and oxidative stress responses compared to females. Relationships between these responses and concentrations of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were also observed. Specifically, the catalytic assays for EROD and BROD (not PROD and MROD) showed sex-differences between male and female crocodiles and paralleled immunochemically determined CYP1A and CYP3A protein levels; the relatively similar levels of PAHs in both sexes suggest an estrogen-mediated reduction of this pathway in females. The antioxidant system exhibited higher levels in male crocodiles with slight or significant higher values for catalase (CAT), glutathione reductase (GR), glutathione peroxidases-H2O2 (GPx-H2O2), glutathione peroxidases-Cu (GPx-Cu), total antioxidant capacity towards peroxyl radicals (TOSC-ROO) and hydroxyl radicals (TOSC-HO), total glutathione (GSH) and malondialdehyde (MDA). On the other hand, the activities of acyl-CoA oxidase (AOX) and glutathione S-transferases (GST) were significantly higher in females. Principal component analysis (PCA) produced significant groupings that revealed correlative relationships (both positive and negative) between biotransformation/oxidative stress variables and liver PAHs and aliphatic hydrocarbon burden. The overall results suggest that these captive pre-slaughter crocodiles exhibited adverse exposure responses to anthropogenic aquatic contaminants with potentially relevant effects on key cellular pathways, and these responses may be established as relevant species biomarkers of exposure and effects in this endangered species. PMID

  18. Characterization of the novel antibacterial peptide Leucrocin from crocodile (Crocodylus siamensis) white blood cell extracts.

    PubMed

    Pata, Supawadee; Yaraksa, Nualyai; Daduang, Sakda; Temsiripong, Yosapong; Svasti, Jisnuson; Araki, Tomohiro; Thammasirirak, Sompong

    2011-05-01

    Four novel antibacterial peptides, Leucrocin I-IV from Siamese crocodile white blood cell extracts were purified by reverse phase high performance liquid chromatography (RP-HPLC). Leucrocins exhibit strong antibacterial activity towards Staphylococcus epidermidis, Salmonella typhi and Vibrio cholerae. The peptides were 7-10 residues in length with different primary structure. The amino acid sequence of Leucrocin I is NGVQPKY with molecular mass around 806.99 Da and Leucrocin II is NAGSLLSGWG with molecular mass around 956.3 Da. Further, the interaction between peptides and bacterial membranes as part of their killing mechanism was studied by fluorescence and electron microscopy. The outer membrane and cytoplasmic membrane was the target of action of Leucrocins as assayed in model membrane by release of β-galactosidase due to the membrane permeabilization. Finally, the hemolytic effect was tested against human red blood cell. Leucrocin I, III and IV showed less toxicity against human red blood cells than Leucrocin II. PMID:21184776

  19. The continuously growing central nervous system of the Nile crocodile (Crocodylus niloticus).

    PubMed

    Ngwenya, Ayanda; Patzke, Nina; Spocter, Muhammad A; Kruger, Jean-Leigh; Dell, Leigh-Anne; Chawana, Richard; Mazengenya, Pedzisai; Billings, Brendon K; Olaleye, Olatunbosun; Herculano-Houzel, Suzana; Manger, Paul R

    2013-10-01

    It is a central assumption that larger bodies require larger brains, across species but also possibly within species with continuous growth throughout the lifetime, such as the crocodile. The current study investigates the relationships between body growth (length and mass) and the rates of growth of various subdivisions of the central nervous system (CNS) (brain, spinal cord, eyes) in Nile crocodiles weighing between 90 g and 90 kg. Although the brain appears to grow in two phases in relation to body mass, initially very rapidly then very slowly, it turns out that brain mass increases continuously as a power function of body mass with a small exponent of 0.256, such that a 10-fold increase in body mass is accompanied by a 1.8-fold in brain mass. Eye volume increases slowly with increasing body mass, as a power function of the latter with an exponent of 0.37. The spinal cord, however, grows more rapidly in mass, accompanying body mass raised to an exponent of 0.54, and increasing in length as predicted, with body mass raised to an exponent of 0.32 (close to the predicted 1/3). While supporting the expectation formulated by Jerison that larger bodies require larger brains to operate them, our findings show that: (1) the rate of increase in brain size is very small compared to body growth; and (2) different parts of the CNS grow at different rates accompanying continuous body growth, with a faster increase in spinal cord mass and eye volume, than in brain mass. PMID:23832836

  20. The accessory role of the diaphragmaticus muscle in lung ventilation in the estuarine crocodile Crocodylus porosus.

    PubMed

    Munns, Suzanne L; Owerkowicz, Tomasz; Andrewartha, Sarah J; Frappell, Peter B

    2012-03-01

    Crocodilians use a combination of three muscular mechanisms to effect lung ventilation: the intercostal muscles producing thoracic movement, the abdominal muscles producing pelvic rotation and gastralial translation, and the diaphragmaticus muscle producing visceral displacement. Earlier studies suggested that the diaphragmaticus is a primary muscle of inspiration in crocodilians, but direct measurements of the diaphragmatic contribution to lung ventilation and gas exchange have not been made to date. In this study, ventilation, metabolic rate and arterial blood gases were measured from juvenile estuarine crocodiles under three conditions: (i) while resting at 30°C and 20°C; (ii) while breathing hypercapnic gases; and (iii) during immediate recovery from treadmill exercise. The relative contribution of the diaphragmaticus was then determined by obtaining measurements before and after transection of the muscle. The diaphragmaticus was found to make only a limited contribution to lung ventilation while crocodiles were resting at 30°C and 20°C, and during increased respiratory drive induced by hypercapnic gas. However, the diaphragmaticus muscle was found to play a significant role in facilitating a higher rate of inspiratory airflow in response to exercise. Transection of the diaphragmaticus decreased the exercise-induced increase in the rate of inspiration (with no compensatory increases in the duration of inspiration), thus compromising the exercise-induced increases in tidal volume and minute ventilation. These results suggest that, in C. porosus, costal ventilation alone is able to support metabolic demands at rest, and the diaphragmaticus is largely an accessory muscle used at times of elevated metabolic demand. PMID:22323207

  1. Molecular cloning, recombinant expression and antibacterial activity analysis of hepcidin from Simensis crocodile (Crocodylus siamensis).

    PubMed

    Hao, Juan; Li, Yan-Wei; Xie, Ming-Quan; Li, An-Xing

    2012-01-01

    Hepcidin, a cysteine-rich cationic antibacterial peptide, plays an important role in human defense against pathogen infection. However, its role in reptile immune response and whether it is involved in antibacterial immune have not yet been proven. In order to study the antibacterial activity of Crocodylus siamensis hepcidin (Cshepc), a common reptile which lives in topic region of Southeast Asia, a cDNA sequence of Cshepc was cloned, which included an open reading frame (ORF) of 300 bp encoding a 99 amino acid preprohepcidin. Cshepc has eight cysteines formed four conserved disulfide bridges, similarly to that of human's. Sequence analysis showed that Cshepc mature peptide was more conserved than that of preprohepcidin. Tissue expression analysis indicated that Cshepc transcripts were highly expressed in the liver, muscle and heart of C. siamensis. Recombinant expressed hepcidin could significantly inhibit the growth of the Gram-negative bacteria Escherichia coli and Aeromonas sobria as well as the Gram-positive bacterium Staphylococcus aureus, and Bacillus subtilis in vitro, suggesting that Cshepc, like human hepcidin could play a role in the antibacterial function in hosts innate immune response. PMID:22967859

  2. The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.

    PubMed

    Myburgh, Jan G; Kirberger, Robert M; Steyl, Johan C A; Soley, John T; Booyse, Dirk G; Huchzermeyer, Fritz W; Lowers, Russel H; Guillette, Louis J

    2014-01-01

    The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions. PMID:24831995

  3. Comparative analysis of hatching rates and clutch sizes of Nile crocodile (Crocodylus niloticus) eggs collected on- and off-farm in Zimbabwe.

    PubMed

    Khosa, Patricia; Imbayarwo-Chikosi, Venancio Edward; Hamandishe, Vimbai

    2012-04-01

    The Nile crocodile (Crocodylus niloticus) is a large aquatic reptile predominant in the tropics in Africa and Zimbabwe in particular. Clutch sizes and hatching rates of Nile crocodile eggs collected from the wild and on-farm in Lowveld, Highveld and Kariba regions of Zimbabwe were evaluated. A total of 274 egg records for the period 2000 to 2008 from 39 farms were collected from the Crocodile Farmers Association of Zimbabwe. The effect of source of eggs was analysed using the non-parametric one way analysis of variance procedure of SAS Version 9.1.3. Wilcoxon signed rank test for independent samples was used to compare the mean hatching rates and clutch sizes for eggs collected from the different sources by region. The degree of association between clutch sizes and the hatching rates by source and region was determined using the Spearman's rank correlation test. Source of eggs had no effect (P > 0.05) on hatching rates in all the regions but significantly influenced (P < 0.05) clutch sizes in Lowveld and Kariba. In these regions, clutch sizes in the wild were significantly (P < 0.05) higher than those on-farm. Correlation estimates between clutch size and hatching rates were weak and non-significant (P > 0.05) for the different sources of eggs in all regions. Full utilization of the wild resource would reduce challenges relating to shortage of captive breeders and high cost of rearing breeders and hence increase productivity. PMID:21947863

  4. Cloning, Expression, and Characterization of Siamese Crocodile (Crocodylus siamensis) Hemoglobin from Escherichia coli and Pichia pastoris.

    PubMed

    Anwised, Preeyanan; Jangpromma, Nisachon; Temsiripong, Theeranan; Patramanon, Rina; Daduang, Sakda; Jitrapakdee, Sarawut; Araki, Tomohiro; Klaynongsruang, Sompong

    2016-08-01

    Recombinant Crocodylus siamensis hemoglobin (cHb) has been constructed and expressed using Escherichia coli as the expression system in conjunction with a trigger factor from the Cold-shock system as the fusion protein. While successful processing as soluble protein in E. coli was achieved, the net yields of active protein from downstream purification processes remained still unsatisfactory. In this study, cHb was constructed and expressed in the eukaryotic expression system Pichia pastoris. The results showed that cHb was excreted from P. pastoris as a soluble protein after 72 h at 25 °C. The amino acid sequence of recombinant cHb was confirmed using LC-MS/MS. Indeed, the characteristic of Hb was investigated by external heme incorporation. The UV-Vis profile showed a specific pattern of the absorption at 415 nm, indicating the recombinant cHb was formed complex with heme, resulting in active oxyhemoglobin (OxyHb). This result suggests that the heme molecules were fully combined with heme binding site of the recombinant cHb, thus producing characteristic red color for the OxyHb at 540 and 580 nm. The results revealed that the recombinant cHb was prosperously produced in P. pastoris and exhibited a property as protein-ligand binding. Thus, our work described herein offers a great potential to be applied for further studies of heme-containing protein expression. It represents further pleasing option for protein production and purification on a large scale, which is important for determination and characterization of the authenticity features of cHb proteins. PMID:27301987

  5. Effect of nesting environment on incubation temperature and hatching success of Morelet's crocodile (Crocodylus moreletii) in an urban lake of Southeastern Mexico.

    PubMed

    López-Luna, Marco A; Hidalgo-Mihart, Mircea G; Aguirre-León, Gustavo; González-Ramón, Mariana Del C; Rangel-Mendoza, Judith A

    2015-01-01

    Incubation temperature is an important aspect in terms of biological performance among crocodiles, and several controlled experiments have demonstrated a significant relationship between incubation temperature, success in hatching and survival of hatchlings. However, a few studies have tested these relationships in the wild. The objective of this study was to determine the relationship of nest characteristics and environment (hatch year, nest basal area and height, clutch size, distance to shore line, and vegetation cover), to incubation temperature and hatching success among Morelet's crocodile (Crocodylus moreletii). The study was carried out during the nesting seasons of Morelet's crocodile, from 2007 to 2009 in the Laguna de Las Ilusiones, an urban lake located in Villahermosa, Tabasco, Mexico. We physically characterized 18 nests and inserted a temperature data logger in each nest chamber. At the end of the nesting season and prior to hatching, we recovered the crocodile eggs and data loggers and calculated hatching success, under laboratory conditions. We related the environmental variables of the nest with the mean and fluctuation (standard deviation) of nest temperature, using linear models. We also related the environmental variables affecting the nest, to mean nest temperature and fluctuation in incubation temperature and to hatching success, using linear models. Although we found differences in incubation temperature between nests, mean incubation temperature did not differ between years, but there were differences in nest thermal fluctuation between years. The mean incubation temperature for 11 nests (61.1%) was lower than the suggested Female-Male pivotal temperature (producing 50% of each sex) for this species, and all hatchlings obtained were males. There were no differences in clutch size between years, but hatching success varied. Our study indicates that hatching success depends on certain environmental variables and nest conditions to which the

  6. On the morphology and taxonomy of Griphobilharzia amoena Platt and Blair, 1991 (Schistosomatoidea), a dioecious digenetic trematode parasite of the freshwater crocodile, Crocodylus johnstoni, in Australia.

    PubMed

    Platt, Thomas R; Hoberg, Eric P; Chisholm, Leslie A

    2013-10-01

    Griphobilharzia amoena Platt and Blair, 1991 was originally described as a dioecious trematode, parasitic in the circulatory system of the Australian freshwater crocodile, Crocodylus johnstoni, with the female completely enclosed in a gynecophoric chamber of the male and the 2 worms oriented anti-parallel to each other. A recent publication questions the original description, arguing that G. amoena is monoecious and, as a consequence, the species was transferred to Vasotrema Stunkard, 1928 (Spirorchiidae) as Vasotrema amoena n. comb. We provide photomicrographic evidence that the original description of G. amoena is correct and that Griphobilharzia Platt and Blair, 1991, is a valid monotypic genus containing G. amoena. An accurate understanding of the anatomy of G. amoena is not trivial and has implications for revealing the complex origins and evolution of the dioecious condition within the Schistosomatoidea. PMID:24099322

  7. On the Morphology and Taxonomy of Griphobilharzia amoena Platt and Blair, 1991 (Schistosomatoidea), a Dioecious Digenetic Trematode Parasite of the Freshwater Crocodile, Crocodylus johnstoni, in Australia.

    PubMed

    Platt, Thomas Reid; Hoberg, Eric P; Chisholm, Leslie A

    2013-05-01

    Abstract Griphobilharzia amoena Platt and Blair, 1991 was originally described as a dioecious trematode parasitic in the circulatory system of the Australian freshwater crocodile, Crocodylus johnstoni, with the female completely enclosed in a gynecophoric chamber of the male, and the 2 worms oriented anti-parallel to each other. A recent publication questions the original description arguing that G. amoena is monoecious and as a consequence, the species was transferred to Vasotrema Stunkard, 1928 (Spirorchiidae) as V. amoena n. comb. We provide photomicrographic evidence that the original description of G. amoena is correct and that Griphobilharzia Platt and Blair, 1991, is a valid monotypic genus containing G. amoena. An accurate understanding of the anatomy of G. amoena is not trivial and has implications for revealing the complex origins and evolution of the dioecious condition within the Schistosomatoidea. PMID:23656536

  8. Recovery rates, serotypes, and antimicrobial susceptibility patterns of salmonellae isolated from cloacal swabs of wild Nile crocodiles (Crocodylus niloticus) in Zimbabwe.

    PubMed

    Madsen, M; Hangartner, P; West, K; Kelly, P

    1998-03-01

    Samples from the cloaca and the ventral skin surface of 67 Nile crocodiles (Crocodylus niloticus) captured in four uninhabited areas at Lake Kariba, Zimbabwe, were cultured for Salmonella. All the skin samples tested negative for Salmonella, whereas 18 of 67 (26.9%) cloacal samples grew Salmonella. Significantly more males than females yielded Salmonella, but no statistically significant correlation among salmonella carriage, body size, and age was recorded. Ten different serotypes of S. enterica belonging to the subspecies enterica, salamae, and diarizonae were isolated. All isolates belonging to subspecies enterica displayed invasive properties in an experimental mouse model and thus exhibited pathogenic potential, whereas none of the other isolates were invasive. In general, isolates were sensitive to a number of commonly used antimicrobials, except for three isolates that were resistant to streptomycin. PMID:9638622

  9. Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela.

    PubMed

    Rossi Lafferriere, Natalia A; Antelo, Rafael; Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ayarzagüena, José; Ginsberg, Joshua R; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George

    2016-01-01

    The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela. PMID:26982578

  10. Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela

    PubMed Central

    Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ginsberg, Joshua R.; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George

    2016-01-01

    The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela. PMID:26982578

  11. Prevalence of neutralizing antibodies against West Nile virus (WNV) in monkeys (Ateles geoffroyi and Alouatta pigra) and crocodiles (Crocodylus acutus and C. acutus-C. moreletti hybrids) in Mexico.

    PubMed

    Loza-Rubio, E; Rojas-Anaya, E; López-Ramírez, R Del C; Saiz, J C; Escribano-Romero, E

    2016-08-01

    West Nile virus (WNV) is a mosquito-borne neurotropic viral pathogen maintained in an enzootic cycle between mosquitoes (vectors) and birds (natural hosts) with equids, humans, and other vertebrates acting as dead-end hosts. WNV activity in Mexico has been reported in several domestic and wild fauna and in humans, and the virus has been isolated from birds, mosquitoes, and humans. However, no serological studies have been conducted in monkeys, and only two in a limited number of crocodiles (Crocodylus moreletii). Here we present data on the prevalence of neutralizing antibodies against WNV in 53 healthy wild monkeys (49 Ateles geoffroyi and four Alouatta pigra), and 80 semi-captive healthy crocodiles (60 C. acutus and 20 C. acutus-C. moreletti hybrids) sampled during 2012. None of the monkey sera neutralized WNV, whereas 55% of the crocodile sera presented neutralizing antibodies against WNV. These results can contribute to the design of surveillance programmes in Mexico. PMID:27097655

  12. A preliminary disease survey in the wild Nile crocodile (Crocodylus niloticus) population in the Okavango Delta, Botswana.

    PubMed

    Leslie, A J; Lovely, C J; Pittman, J M

    2011-09-01

    The objective of this study was to conduct a preliminary survey of diseases that might be present in the wild Nile crocodile population in the Okavango Delta, Botswana. Blood samples were collected from crocodiles ranging in size from 34.0 cm to 463.0 cm total length. Samples were examined for blood parasites and underwent a haematological analysis. Before release the crocodiles were examined for various clinical abnormalities. Of the 144 crocodiles examined, none were visibly sick or displayed any signs of disease. No antibodies to Mycoplasma crocodyli were detected. Hepatozoon pettiti was present in 55.3% of blood smears examined, but there was no significant difference in any of the haematological values between the infected and uninfected crocodiles, and a high prevalence of Hepatozoon infection is not uncommon in other species. Only 7.6% of the examined crocodiles were infested with leeches. Further research is required for several of the crocodilian diseases, in particular to elucidate the role of wild crocodilians as reservoirs of infection. PMID:22332299

  13. Use of immunoblotting to detect antibodies to Mycoplasma crocodyli infection in the sera of crocodiles (Crocodylus niloticus).

    PubMed

    Dawo, Fufa; Mohan, Krishna

    2008-02-01

    An immunoblotting protocol for the detection of antibodies to Mycoplasma crocodyli was developed using sonicated antigen of the reference strain 266/93. Immunoblotting detected nine reacting antigens, of which the 33 and 40kDa antigens were immunodominant. There was no difference in reactivity of the antigens against sera obtained from vaccinated and infected crocodiles. Both antigens are candidates for other serological and molecular studies. This is the first report to develop and apply an immunoblotting test for detection of antibody to M. crocodyli infection in crocodiles. PMID:17360201

  14. 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

  15. Design and synthesis of cationic antibacterial peptide based on Leucrocin I sequence, antibacterial peptide from crocodile (Crocodylus siamensis) white blood cell extracts.

    PubMed

    Yaraksa, Nualyai; Anunthawan, Thitiporn; Theansungnoen, Tinnakorn; Daduang, Sakda; Araki, Tomohiro; Dhiravisit, Apisak; Thammasirirak, Sompong

    2014-03-01

    Leucrocin I is an antibacterial peptide isolated from crocodile (Crocodylus siamensis) white blood cell extracts. Based on Leucrocin I sequence, cationic peptide, NY15, was designed, synthesized and evaluated for antibacterial activity against Bacillus sphaericus TISTR 678, Bacillus megaterium (clinical isolate), Vibrio cholerae (clinical isolate), Salmonella typhi (clinical isolate), Salmonella typhi ATCC 5784 and Escherichia coli 0157:H7. The efficacy of the peptide made from all L-amino acids was also compared with all D-amino acids. The peptide made from all D-amino acids was more active than the corresponding L-enantiomer. In our detailed study, the interaction between peptides and the cell membrane of Vibrio cholerae as part of their killing mechanism was studied by fluorescence and electron microscopy. The results show that the membrane was the target of action of the peptides. Finally, the cytotoxicity assays revealed that both L-NY15 and D-NY15 peptides are non-toxic to mammalian cells at bacteriolytic concentrations. PMID:24192554

  16. Eustrongylides sp. (Nematoda: Dioctophymatoidea) from the stomach of a Nile crocodile, Crocodylus niloticus Laurenti, 1768, in Botswana.

    PubMed

    Junker, K; Bain, O; Boomker, J

    2006-12-01

    During a study conducted between 2003 and 2005 on the diet of Nile crocodiles in Botswana, two young adult nematodes, one male and one female, belonging to the genus Eustrongylides Jägerskiöld, 1909 were recovered from the stomach contents of one of these animals. The caudal bursa of the male is present and the ejaculatory duct could be identified, but the spicule could not be seen. The vulva of the female has opened and the anus is situated on a terminal protruberance. Measurements and drawings of these specimens are provided, together with some data on the occurrence and life-cycles of members of the genus Eustrongylides in crocodilians world-wide and in African hosts in particular. Piscivorous birds are the usual final hosts of these nematodes. It is probable that the specimens described herein had developed in a paratenic fish host, and that the latter had been eaten by the crocodile. PMID:17283733

  17. Hepatic and renal concentrations of 10 trace elements in crocodiles (Crocodylus niloticus) in the Kafue and Luangwa rivers in Zambia.

    PubMed

    Almli, Bjørn; Mwase, Maxwell; Sivertsen, Tore; Musonda, Mike M; Flåøyen, Arne

    2005-01-20

    Hepatic and renal concentrations of the elements arsenic, cadmium, cobalt, copper, lead, manganese, mercury, molybdenum, selenium and zinc were determined in samples collected from four crocodiles from the Kafue River, Kafue National Park and five crocodiles from the Luangwa River, Luangwa National Park, Zambia. The concentrations of the essential elements were similar to those reported in other vertebrates. Arsenic and cadmium concentrations were low (medians below 0.05 microg As/g and below 0.16 microg Cd/g, wet wt.). Mercury and lead concentrations were several orders of magnitude higher (medians up to 3.7 microg Hg/g, and up to 8.7 microg Pb/g, all wet wt.) than in hippopotami from the same rivers, probably as a result of food-chain biomagnification. Judging by the results obtained in this study, pollution from the mining activity around the Kafue River drainage area in the Copperbelt region has not significantly influenced the trace element concentrations in tissues of the crocodiles in the Kafue National Park. The trace element concentrations measured may serve as reference values in future studies on crocodilians. PMID:15626380

  18. Continued Growth of the Central Nervous System without Mandatory Addition of Neurons in the Nile Crocodile (Crocodylus niloticus).

    PubMed

    Ngwenya, Ayanda; Patzke, Nina; Manger, Paul R; Herculano-Houzel, Suzana

    2016-01-01

    It is generally believed that animals with larger bodies require larger brains, composed of more neurons. Across mammalian species, there is a correlation between body mass and the number of brain neurons, albeit with low allometric exponents. If larger bodies imperatively require more neurons to operate them, then such an increase in the number of neurons should be detected across individuals of a continuously growing species, such as the Nile crocodile. In the current study we use the isotropic fractionator method of cell counting to determine how the number of neurons and non-neurons in 6 specific brain regions and the spinal cord change with increasing body mass in the Nile crocodile. The central nervous system (CNS) structures examined all increase in mass as a function of body mass, with allometric exponents of around 0.2, except for the spinal cord, which increases with an exponent of 0.6. We find that numbers of non-neurons increase slowly, but significantly, in all CNS structures, scaling as a function of body mass with exponents ranging between 0.1 and 0.3. In contrast, numbers of neurons scale with body mass in the spinal cord, olfactory bulb, cerebellum and telencephalon, with exponents of between 0.08 and 0.20, but not in the brainstem and diencephalon, the brain structures that receive inputs and send outputs to the growing body. Densities of both neurons and non-neurons decrease with increasing body mass. These results indicate that increasing body mass with growth in the Nile crocodile is associated with a general addition of non-neurons and increasing cell size throughout CNS structures, but is only associated with an addition of neurons in some structures (and at very small rates) and not in those brain structures directly connected to the body. Larger bodies thus do not imperatively require more neurons to operate them. PMID:26914769

  19. Trichinella zimbabwensis n.sp. (Nematoda), a new non-encapsulated species from crocodiles (Crocodylus niloticus) in Zimbabwe also infecting mammals.

    PubMed

    Pozio, E; Foggin, C M; Marucci, G; La Rosa, G; Sacchi, L; Corona, S; Rossi, P; Mukaratirwa, S

    2002-12-19

    Since 1995, Trichinella larvae have been detected in 39.5% of farmed crocodiles (Crocodylus niloticus) in Zimbabwe. Morphological, biological, biochemical and molecular studies carried out on one isolate from a farmed crocodile in 2001 support the conclusion that this parasite belongs to a new species, which has been named Trichinella zimbabwensis n.sp. This species, whose larvae are non-encapsulated in host muscles, infects both reptiles and mammals. The morphology of adults and larvae is similar to that of Trichinella papuae. Adults of T. zimbabwensis cross in both directions with adults of T. papuae (i.e. male of T. zimbabwensis per female of T. papuae and male of T. papuae per female of T. zimbabwensis), producing F1 offspring which produce very few and less viable F2 larvae. Muscle larvae of T. zimbabwensis, like those of T. papuae, do not infect birds. Three allozymes (of a total of 10) are diagnostic between T. zimbabwensis and T. papuae, and five are diagnostic between T. zimbabwensis and Trichinella pseudospiralis, the third non-encapsulated species. The percentage of the pairwise alignment identity between T. zimbabwensis and the other Trichinella species for the cytochrome oxidase subunit I gene, the large subunit ribosomal-DNA (mt-lsrDNA) gene and the expansion segment five, shows that T. zimbabwensis is more similar to the two non-encapsulated species T. papuae (91% for cytochrome oxidase I; 96% for mt-lsrDNA; and 88% for expansion segment five) and T. pseudospiralis (88% for cytochrome oxidase I; 90% for mt-lsrDNA; and 66-73% for expansion segment five) than to any of the encapsulated species (85-86% for cytochrome oxidase I; 88-89% for mt-lsrDNA; and 71-79% for expansion segment five). This is the first non-encapsulated species discovered in Africa. The finding of a new Trichinella species that infects both reptiles and mammals suggests that the origin of Trichinella parasites dates back further than previously believed and can contribute to

  20. Molecular cloning and expression of α-globin and β-globin genes from crocodile (Crocodylus siamensis).

    PubMed

    Anwised, Preeyanan; Kabbua, Thai; Temsiripong, Theeranan; Dhiravisit, Apisak; Jitrapakdee, Sarawut; Araki, Tomohiro; Yoneda, Kazunari; Thammasirirak, Sompong

    2013-03-01

    The first report of complete nucleotide sequences for α- and β-globin chains from the Siamese hemoglobin (Crocodylus siamensis) is given in this study. The cDNAs encoding α- and β-globins were cloned by RT-PCR using the degenerate primers and by the rapid amplification of cDNA ends method. The full-length α-globin cDNA contains an open reading frame of 423 nucleotides encoding 141 amino acid residues, whereas the β-globin cDNA contains an open reading frame of 438 nucleotides encoding 146 amino acid residues. The authenticity of both α- and β-globin cDNA clones were also confirmed by the heterologous expression in Escherichia coli (E. coli). This is the first time that the recombinant C. siamensis globins were produced in prokaryotic system. Additionally, the heme group was inserted into the recombinant proteins and purified heme-bound proteins were performed by affinity chromatography using Co(2+)-charged Talon resins. The heme-bound proteins appeared to have a maximum absorbance at 415 nm, indicated that the recombinant proteins bound to oxygen and formed active oxyhemoglobin (HbO2). The results indicated that recombinant C. siamensis globins were successfully expressed in prokaryotic system and possessed an activity as ligand binding protein. PMID:23463382

  1. 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. PMID:23558556

  2. Assessment of selected biochemical parameters and humoral immune response of Nile crocodiles (Crocodylus niloticus) experimentally infected with Trichinella zimbabwensis.

    PubMed

    La Grange, Louis J; Mukaratirwa, Samson

    2014-01-01

    Fifteen crocodiles were randomly divided into three groups of five animals. They represented high-infection, medium-infection and low-infection groups of 642 larvae/kg, 414 larvae/kg and 134 larvae/kg bodyweight, respectively. The parameters assessed were blood glucose, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), aspartate transaminase (AST) and alanine transaminase (ALT). The humoral immune response to Trichinella zimbabwensis infection was evaluated in all three groups by an indirect ELISA method. The results showed deviations from normal parameters of blood glucose, CPK, LDH, AST and ALT when compared with reported levels in uninfected reptiles. Contrary to studies involving mammals, hypoglycaemia was not observed in the infected groups in this study. Peak values of blood glucose were reached on post-infection (PI) Day 49, Day 42 and Day 35 in the high-infection, medium-infection and low-infection groups, respectively. Peak values of LDH and AST were observed on PI Day 56, Day 49 and Day 42 in the high-infection, medium-infection and low-infection groups, respectively. Peak values of CPK were observed on Day 35 PI in all three groups. Peak ALT values were reached on Day 56 in the high-infection group and on Day 28 PI in both the medium-infection and low-infection groups. No correlations between the biochemical parameters and infection intensity were observed. Peak antibody titres were reached on Day 49 PI in the medium-infection group, and on Day 42 PI in both the high-infection and low-infection groups. Infection intensity could not be correlated with the magnitude of the humoral immune response or time to sero-conversion. Results from this study were in agreement with results reported in mammals infected with other Trichinella species and showed that antibody titres could not be detected indefinitely. PMID:25686027

  3. Nuclear microprobe analysis of lead profile in crocodile bones

    NASA Astrophysics Data System (ADS)

    Orlic, I.; Siegele, R.; Hammerton, K.; Jeffree, R. A.; Cohen, D. D.

    2003-09-01

    Elevated concentrations of lead were found in Australian free ranging saltwater crocodile ( Crocodylus porosus) bone and flesh. Lead shots were found as potential source of lead in these animals. ANSTO's heavy ion nuclear microprobe was used to measure the distribution of Pb in a number of bones and osteoderms. The aim was to find out if elevated Pb concentration remains in growth rings and if the concentration is correlated with the blood levels recorded at the time. Results of our study show a very distinct distribution of accumulated Pb in bones and osteoderms as well as good correlation with the level of lead concentration in blood. To investigate influence of ion species on detection limits measurements of the same sample were performed by using 3 MeV protons, 9 MeV He ions and 20 MeV carbon ions. Peak to background ratios, detection limits and the overall 'quality' of obtained spectra are compared and discussed.

  4. Development and application of an indirect ELISA test for the detection of antibodies to Mycoplasma crocodyli infection in crocodiles (Crocodylus niloticus).

    PubMed

    Dawo, Fufa; Mohan, Krishna

    2007-01-31

    Non-availability of a standardized rapid serodiagnostic test for quick and accurate diagnosis of Mycoplasma crocodyli (M. crocodyli) infection in crocodiles was the underlining reason for conducting the present study. An indirect enzyme-linked immunosorbent assay (iELISA) for the detection of antibodies (Ab) to M. crocodyli infection in crocodile sera was developed using sonicated antigen (Ag) and anti-crocodile conjugate. The iELISA test was optimised with different reagents and at different steps. A cut-off value of percent positive greater than or equal to 53.47% resulted in an estimated sensitivity and specificity of 85.67 and 100%, respectively. The developed iELISA could be used for detection of Abs to M. crocodyli infection in crocodiles and may enable to understand the transmission of the disease. PMID:17014973

  5. Assessment of microsatellites in estimating inter- and intraspecific variation among Neotropical Crocodylus species.

    PubMed

    Bashyal, A; Gross, B A; Venegas-Anaya, M; Lowrance, F; Densmore Iii, L D

    2014-01-01

    We tested microsatellites that were developed for the saltwater crocodile (Crocodylus porosus) for cross-species amplification and to provide an estimate of inter- and intraspecific variation among four species of Neotropical crocodiles (C. rhombifer, C. intermedius, C. acutus, and C. moreletii). Our results indicated that with the exception of 2 loci in C. intermedius, all 10 microsatellite loci were successfully amplified in the 4 species, producing a set of variably sized alleles that ranged in number between 2 and 14 alleles per locus. Similarly, private alleles (i.e., unique alleles) also were reported in all 4 species for at least 3 loci. The mean observed and expected heterozygosities (averaged across species for all 10 loci combined) ranged from 0.39 to 0.77 and from 0.44 to 0.78, respectively. In addition to this, we evaluated these microsatellites in 2 populations of C. acutus and C. moreletii to assess their utility in estimating intraspecific levels of polymorphisms. These microsatellites also showed considerable allelic variation in population level analysis. The set of 10 microsatellite loci in our study had the potential to be used as a tool in population and conservation genetic studies of Neotropical crocodiles. PMID:25117304

  6. Pentastomid infections in Nile crocodiles (Crocodylus niloticus) in the Kruger National Park, South Africa, with a description of the males of Alofia simpsoni.

    PubMed

    Junker, K; Boomker, J; Bolton, L A

    1999-06-01

    Two Nile crocodiles were obtained from two different localities in the Kruger National Park, one a healthy specimen, the other in a severely debilitated condition. Both were males over 3 m long and both harboured the three pentastome genera Sebekia, Alofia and Leiperia. The genus Sebekia was represented by three species, Sebekia wedli Giglioli, 1922, Sebekia cesarisi Giglioli, 1922 and Sebekia okavangoensis Riley & Huchzermeyer, 1995. Of the genus Alofia two species, Alofia simpsoni Riley, 1994 and Alofia nilotici Riley & Huchzermeyer, 1995 were found. The male of A. simpsoni, formerly unknown, is described and the description of the females emended. Leiperia cincinnalis Sambon, 1922 was the only Leiperia present. Whereas Sebekia and Alofia were recovered from the bronchioles and lung parenchyma, female Leiperia occurred in the trachea and bronchi, and infective larvae as well as immature males and females, were collected from the lungs, the heart and the aorta. Adult Subtriquetra (Family Subtriquetridae) were not present in the nasopharynx of either crocodile. The intensity of infection was low in the healthy crocodile and had no negative effect on the host. In contrast, the debilitated crocodile was heavily infected and its poor condition is ascribed to its high pentastome burden. Histopathology revealed lesions in the tracheal wall and the lungs accompanied by chronic granulomata with secondary fungal infection as well as severe chronic multifocal granulomatous pneumonia. PMID:10486822

  7. Comparison of biochemical stress indicators in juvenile captive estuarine crocodiles (Crocodylus porosus) following physical restraint or chemical restraint by midazolam injection.

    PubMed

    Olsson, Annabelle; Phalen, David

    2013-07-01

    Using a prospective, randomized study design we demonstrate that midazolam sedation minimizes acidosis compared with physical restraint in captive juvenile estuarine crocodiles during handling or noninvasive procedures at preferred body temperature. A dose of midazolam (5.0 mg/kg) was administered intramuscularly into the forelimb of 20 male estuarine crocodiles weighing 2-3.5 kg. Their heart and respiratory rate and degree of sedation were monitored until recovery and then daily for 7 subsequent days. Blood samples were taken at 30, 60, 90, 180, and 360 min. We recorded lactate, partial pressure of carbon dioxide (CO2), hematocrit, glucose, and blood pH. A second group (1.9-2.6 kg) was physically restrained for 5 min and the same parameters recorded. Physically restrained animals demonstrated elevated heart rate, respiratory rate, glucose, lactate, and anion gap compared with the midazolam-treated group. Physically restrained animals had lower pH, bicarbonate, and partial pressure of CO2 compared with the midazolam-treated group. Behavior in the physically restrained group in the days following the study was disrupted, with reluctance to feed and bask, compared with midazolam-treated animals whose behavior was normal. We conclude that midazolam administered in the forelimb of captive estuarine crocodiles of 2-3.5 kg provides predictable onset and duration of sedation enabling physical examination, sample collection, and translocation of the animals with minimal disturbance to lactate, pH, and CO2. Behavior following recovery appears normal. PMID:23778605

  8. Selected chemical parameters in the blood and metals in the organs of the Nile crocodile, Crocodylus Niloticus, in the Kruger National Park.

    PubMed

    Swanepoel, D; Boomker, J; Kriek, N P

    2000-06-01

    Healthy and sick crocodiles of varying sizes were examined from the Olifants River in the central part of the Kruger National Park, the Sabi River in the southern part and the Shingwedzi River in the northern region. Blood was collected for the determination of certain parameters and samples of fat, muscle, kidney and liver tissue were collected and analyzed for their heavy metal content. The results of the blood analyses are within the range recorded in the literature, but the metal analyses were inconclusive as similar data are not available for comparison. The results of the metal analyses are presented here for use as baseline and reference data. PMID:11028751

  9. Identification of Indian crocodile species through DNA barcodes.

    PubMed

    Meganathan, P R; Dubey, Bhawna; Jogayya, Kothakota Naga; Haque, Ikramul

    2013-07-01

    The biodiversity of India includes three crocodile species, Crocodylus palustris, Crocodylus porosus, and Gavialis gangeticus, whose status is threatened due to bushmeat crisis and illegal hunting. The crocodilian conservation management requires novel techniques to help forensic analysts to reveal species identity. DNA barcoding is a species identification technique, where a partial cytochrome c oxidase subunit 1 gene is used as a marker for species identification. Herein, the DNA barcoding technique is evaluated for three Indian crocodiles by analyzing an approximately 750-bp barcode region. The alignment result shows interspecific variations between sequences for discrimination of the three Indian crocodiles leading to species identification. The phylogenetic analyses also substantiate the established crocodilian relationships, which add further advantage to use this DNA barcoding approach for Indian crocodiles. This study provides preliminary evidences for the use of DNA barcoding technique in the identification of Indian crocodile species. PMID:23718785

  10. Leiperia cincinnalis Sambon, 1922 (Pentastomida) from Nile crocodiles Crocodylus niloticus in the Kruger National Park, South Africa, with a description of the male.

    PubMed

    Junker, K; Boomker, J; Swanepoel, D; Taraschewski, H

    2000-09-01

    A single male and several adult females of the pentastomid Leiperia cincinnalis were recovered from the trachea of five of six Nile crocodiles examined in 1995 and 1998. Infective larvae, pre-adult males and females, as well as mature males, occurred in clusters in the pulmonary artery but infective larvae and pre-adult females were also occasionally taken from the lungs. Irrespective of the developmental stage, the intensity of infection was 3, 6, 48, 72 and 79. Sixty-four percent of eggs recovered from the posterior part of the uterus of a patent L. cincinnalis female contained fully-developed primary larvae and these were used to infect 24 Mozambique bream Oreochromis mossambicus. Within a week of infection all the fish died and hatched primary larvae were recovered from the stomach and anterior part of the intestine. Eggs that had not hatched were found to be unsegmented. The total primary larval count in seven fish was 18, 12, 1, 25, 16, >40 and >50. Descriptions with detailed measurements are given of the females, the males, the eggs, the primary larvae and the infective larvae of L. cincinnalis. PMID:10937664

  11. Antibodies to West Nile Virus in Wild and Farmed Crocodiles in Southeastern Mexico

    PubMed Central

    Machain-Williams, Carlos; Padilla-Paz, Sergio E.; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J.

    2013-01-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet’s crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has been reported in Mexico, we provide the first evidence of WNV exposure in wild crocodiles in Mexico. PMID:23778623

  12. Antibodies to West Nile virus in wild and farmed crocodiles in southeastern Mexico.

    PubMed

    Machain-Williams, Carlos; Padilla-Paz, Sergio E; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J

    2013-07-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet's crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has been reported in Mexico, we provide the first evidence of WNV exposure in wild crocodiles in Mexico. PMID:23778623

  13. DDE in eggs of two crocodile species from Belize.

    PubMed

    Wu, T H; Rainwater, T R; Platt, S G; McMurry, S T; Anderson, T A

    2000-12-01

    Organochlorine (OC) residues were recently detected in nonviable Morelet's crocodile (Crocodylus moreletii) eggs from northern Belize. To further the assessment of contaminant exposure in Belizean crocodiles, nonviable Morelet's crocodile eggs (n = 11) from southern Belize and American crocodile (Crocodylus acutus) eggs (n = 12) from the coastal zones of Belize were screened for 20 OCs. Results indicated p,p-DDE to be the most prevalent OC (96% occurrence) in eggs examined, with concentrations ranging from 5 to 372 ng/g. These concentrations are similar to those observed in crocodile eggs (10-180 ng/g) from northern Belize. A general trend toward higher DDE concentrations in Morelet's crocodile eggs (mean = 103 ppb) compared with American crocodile eggs (mean = 31 ppb) was observed. However, this trend may be due to site-specific contamination rather than differences in interspecific susceptibility to chemical exposure. Other OCs detected in crocodile eggs included the parent compound, p,p-DDT, and its metabolite, p, p-DDD. PMID:11141295

  14. Crocodile egg sounds signal hatching time.

    PubMed

    Vergne, Amélie L; Mathevon, Nicolas

    2008-06-24

    Crocodilians are known to vocalize within the egg shortly before hatching [1,2]. Although a possible function of these calls - inducing hatching in siblings and stimulating the adult female to open the nest - has already been suggested, it has never been experimentally tested [1-5]. Here, we present the first experimental evidence that pre-hatching calls of Nile crocodile (Crocodylus niloticus) juveniles are informative acoustic signals which indeed target both siblings and mother. PMID:18579090

  15. Infectivity of Trichinella sp. isolated from Crocodylus niloticus to the indigenous Zimbabwean pig (Mukota).

    PubMed

    Mukaratirwa, S; Foggin, C M

    1999-07-01

    An experimental infection of the indigenous Zimbabwean pig (Mukota) with a Trichinella sp. derived from crocodile (Crocodylus niloticus) was performed. The same larval isolates of Trichinella were infected to rats as a control. The muscles of both pigs and rats were found to be heavily infected with the first-stage larvae. The present study constitutes the first report of a successful experimental infection of the pig with Trichinella sp. originating from crocodile. PMID:10501623

  16. Saltwater Wetlands.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Provides information about saltwater wetlands. Contains seven learning activities which deal with "making" a mud snail, plants and animals of mangroves, and the effects of tides on salt marshes. Included are reproducible handouts and worksheets for several of the activities. (TW)

  17. Characterization of crocodile teeth: correlation of composition, microstructure, and hardness.

    PubMed

    Enax, Joachim; Fabritius, Helge-Otto; Rack, Alexander; Prymak, Oleg; Raabe, Dierk; Epple, Matthias

    2013-11-01

    Structure and composition of teeth of the saltwater crocodile Crocodylus porosus were characterized by several high-resolution analytical techniques. X-ray diffraction in combination with elemental analysis and infrared spectroscopy showed that the mineral phase of the teeth is a carbonated calcium-deficient nanocrystalline hydroxyapatite in all three tooth-constituting tissues: Dentin, enamel, and cementum. The fluoride content in the three tissues is very low (<0.1 wt.%) and comparable to that in human teeth. The mineral content of dentin, enamel, and cementum as determined by thermogravimetry is 71.3, 80.5, and 66.8 wt.%, respectively. Synchrotron X-ray microtomography showed the internal structure and allowed to visualize the degree of mineralization in dentin, enamel, and cementum. Virtual sections through the tooth and scanning electron micrographs showed that the enamel layer is comparably thin (100-200 μm). The crystallites in the enamel are oriented perpendicularly to the tooth surface. At the dentin-enamel-junction, the packing density of crystallites decreases, and the crystallites do not display an ordered structure as in the enamel. The microhardness was 0.60±0.05 GPa for dentin, 3.15±0.15 GPa for enamel, 0.26±0.08 GPa for cementum close to the crown, and 0.31±0.04 GPa for cementum close to the root margin. This can be explained with the different degree of mineralization of the different tissue types and is comparable with human teeth. PMID:24091039

  18. Ectromelia in Morelet's crocodile from Belize.

    PubMed

    Rainwater, T R; McMurry, S T; Platt, S G

    1999-01-01

    Two Morelet's crocodiles (Crocodylus moreletii) captured on 21 March 1997 and 20 April 1998 in the New River system, Belize exhibited ectromelia of one forelimb. External and radiograph examination appears to indicate limb agenesis of unknown etiology, as there is no apparent scarring or skeletal trauma. These two individuals represent the only cases of missing limbs from 642 individuals captured in this study and to our knowledge, the first reported cases in Morelet's crocodile. Several factors including age and diet of the reproducing female, extremes in nest conditions (egg incubation temperature and humidity), and exposure to environmental contaminants can cause developmental abnormalities in crocodilians and may have contributed to the condition observed in these animals. Survival rates for hatchling crocodilians are generally low, and embryonic malformations such as ectromelia may constitute an added disadvantage to survival. However, both individuals examined in this study were vigorous and appeared in good condition. PMID:10073362

  19. Ticks from a Morelet's crocodile in Belize.

    PubMed

    Rainwater, T R; Platt, S G; Robbins, R G; McMurry, S T

    2001-10-01

    Parasitism of crocodilians by ticks has rarely been reported, and to our knowledge only seven published accounts exist. On 3 July 1999, we collected four ticks from a subadult Morelet's crocodile (Crocodylus moreletii) captured in northern Belize. These were identified as Amblyomma dissimile (one female), and Amblyomma sp. (two nymphs, one larva). The crocodile was captured on land approximately 100 m from water, and all four ticks were attached to loose skin on the lateral surface of the tail. Crocodilians are most susceptible to terrestrial ectoparasites, including ticks, during overland movements. However, most such movements occur in response to drought, when tick questing activity is suppressed, which likely accounts for the small numbers of tick specimens recorded from crocodilians and the absence of any noticeable impact of parasitism on host fitness. PMID:11763751

  20. Characterization of serum phospholipase a(2) activity in three diverse species of west african crocodiles.

    PubMed

    Merchant, Mark; Juneau, Kate; Gemillion, Jared; Falconi, Rodolfo; Doucet, Aaron; Shirley, Matthew H

    2011-01-01

    Secretory phospholipase A(2), an enzyme that exhibits substantial immunological activity, was measured in the serum of three species of diverse West African crocodiles. Incubation of different volumes of crocodile serum with bacteria labeled with a fluorescent fatty acid in the sn-2 position of membrane lipids resulted in a volume-dependent liberation of fluorescent probe. Serum from the Nile crocodile (Crocodylus niloticus) exhibited slightly higher activity than that of the slender-snouted crocodile (Mecistops cataphractus) and the African dwarf crocodile (Osteolaemus tetraspis). Product formation was inhibited by BPB, a specific PLA(2) inhibitor, confirming that the activity was a direct result of the presence of serum PLA(2). Kinetic analysis showed that C. niloticus serum produced product more rapidly than M. cataphractus or O. tetraspis. Serum from all three species exhibited temperature-dependent PLA(2) activities but with slightly different thermal profiles. All three crocodilian species showed high levels of activity against eight different species of bacteria. PMID:22110960

  1. A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania

    PubMed Central

    Brochu, Christopher A.; Njau, Jackson; Blumenschine, Robert J.; Densmore, Llewellyn D.

    2010-01-01

    Background The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular “horns” over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. Methodology/Principal Findings The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma), in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. Conclusions/Significance The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus. PMID:20195356

  2. An ancient icon reveals new mysteries: mummy DNA resurrects a cryptic species within the Nile crocodile.

    PubMed

    Hekkala, Evon; Shirley, Matthew H; Amato, George; Austin, James D; Charter, Suellen; Thorbjarnarson, John; Vliet, Kent A; Houck, Marlys L; Desalle, Rob; Blum, Michael J

    2011-10-01

    The Nile crocodile (Crocodylus niloticus) is an ancient icon of both cultural and scientific interest. The species is emblematic of the great civilizations of the Nile River valley and serves as a model for international wildlife conservation. Despite its familiarity, a centuries-long dispute over the taxonomic status of the Nile crocodile remains unresolved. This dispute not only confounds our understanding of the origins and biogeography of the 'true crocodiles' of the crown genus Crocodylus, but also complicates conservation and management of this commercially valuable species. We have taken a total evidence approach involving phylogenetic analysis of mitochondrial and nuclear markers, as well as karyotype analysis of chromosome number and structure, to assess the monophyletic status of the Nile crocodile. Samples were collected from throughout Africa, covering all major bioregions. We also utilized specimens from museum collections, including mummified crocodiles from the ancient Egyptian temples at Thebes and the Grottes de Samoun, to reconstruct the genetic profiles of extirpated populations. Our analyses reveal a cryptic evolutionary lineage within the Nile crocodile that elucidates the biogeographic history of the genus and clarifies long-standing arguments over the species' taxonomic identity and conservation status. An examination of crocodile mummy haplotypes indicates that the cryptic lineage corresponds to an earlier description of C. suchus and suggests that both African Crocodylus lineages historically inhabited the Nile River. Recent survey efforts indicate that C. suchus is declining or extirpated throughout much of its distribution. Without proper recognition of this cryptic species, current sustainable use-based management policies for the Nile crocodile may do more harm than good. PMID:21906195

  3. A phylogenetic hypothesis for Crocodylus (Crocodylia) based on mitochondrial DNA: evidence for a trans-Atlantic voyage from Africa to the New World.

    PubMed

    Meredith, Robert W; Hekkala, Evon R; Amato, George; Gatesy, John

    2011-07-01

    The phylogenetic relationships among extant species of Crocodylus (Crocodylia) have been inconsistently resolved by previous systematic studies. Here we used nearly complete mitochondrial (mt) genomes (∼16,200 base pairs) for all described Crocodylus species, eight of which are new to this study, to derive a generally well-supported phylogenetic hypothesis for the genus. Model-based analyses support monophyly of all Asian+Australian species and paraphyly of Crocodylus niloticus (Nile crocodile) with a monophyletic New World clade nested within this species. Wild-caught Nile crocodiles from eastern populations group robustly with the four New World species to the exclusion of Nile crocodiles from western populations, a result that is also favored by parsimony analyses and by various subpartitions of the overall mt dataset. The fossil record of Crocodylus extends back only to the Late Miocene, while the earliest fossils assigned to C. niloticus and to New World Crocodylus are Pliocene. Therefore, in combination with paleontological evidence, mt DNA trees imply a relatively recent migration of Crocodylus from Africa to the Americas, a voyage that would have covered hundreds of miles at sea. PMID:21459152

  4. Role of Chromosome Changes in Crocodylus Evolution and Diversity.

    PubMed

    Srikulnath, Kornsorn; Thapana, Watcharaporn; Muangmai, Narongrit

    2015-12-01

    The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia. PMID:26865840

  5. Role of Chromosome Changes in Crocodylus Evolution and Diversity

    PubMed Central

    Thapana, Watcharaporn; Muangmai, Narongrit

    2015-01-01

    The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia. PMID:26865840

  6. Warm-blooded isochore structure in Nile crocodile and turtle.

    PubMed

    Hughes, S; Zelus, D; Mouchiroud, D

    1999-11-01

    The genomes of warm-blooded vertebrates are characterized by a strong heterogeneity in base composition, with GC-rich and GC-poor isochores. The GC content of sequences, especially in third codon positions, is highly correlated with that of the isochore they are embedded in. In amphibian and fish genomes, GC-rich isochores are nearly absent. Thus, it has been proposed that the GC increase in a part of mammalian and avian genomes represents an adaptation to homeothermy. To test this selective hypothesis, we sequenced marker protein genes in two cold-blooded vertebrates, the Nile crocodile Crocodylus niloticus (10 genes) and the red-eared slider Trachemys scripta elegans (6 genes). The analysis of base composition in third codon position of this original data set shows that the Nile crocodile and the turtle also exhibit GC-rich isochores, which rules out the homeothermy hypothesis. Instead, we propose that the GC increase results from a mutational bias that took place earlier than the adaptation to homeothermy in birds and before the turtle/crocodile divergence. Surprisingly, the isochore structure appears very similar between the red-eared slider and the Nile crocodile than between the chicken and the Nile crocodile. This point questions the phylogenetic position of turtles as a basal lineage of extant reptiles. We also observed a regular molecular clock in the Archosauria, which enables us, by using a more extended data set, to confirm Kumar and Hedges's dating of the bird-crocodile split. PMID:10555283

  7. Molecular cloning of estrogen receptor alpha of the Nile crocodile.

    PubMed

    Katsu, Yoshinao; Myburgh, Jan; Kohno, Satomi; Swan, Gerry E; Guillette, Louis J; Iguchi, Taisen

    2006-03-01

    Estrogens are essential for normal reproductive activity in female and male vertebrates. In female reptiles, they are essential for ovarian differentiation during a critical developmental stage. To understand the molecular mechanisms of estrogen action in the Nile crocodile (Crocodylus niloticus), we have isolated cDNA encoding the estrogen receptor alpha (ERalpha) from the ovary. Degenerate PCR primers specific to ER were designed and used to amplify Nile crocodile cDNA from the ovary. The full-length Nile crocodile ERalpha cDNA was obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequence of the Nile crocodile ERalpha showed high identity to the American alligator ERalpha (98%), caiman ER (98%), lizard ER (82%) and chicken ERalpha (92%), although phylogenetic analysis suggested profound differences in the rate of sequence evolution for vertebrate ER sequences. Expression of ERalpha was observed in the ovary and testis of juvenile Nile crocodiles. These data provide a novel tool allowing future studies examining the regulation and ontogenic expression of ERalpha in crocodiles and expands our knowledge of estrogen receptor evolution. PMID:16455277

  8. Determinants of Habitat Selection by Hatchling Australian Freshwater Crocodiles

    PubMed Central

    Somaweera, Ruchira; Webb, Jonathan K.; Shine, Richard

    2011-01-01

    Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk. PMID:22163308

  9. Hybridization between Crocodylus acutus and Crocodylus moreletii in the Yucatan Peninsula: II. Evidence from microsatellites.

    PubMed

    Rodriguez, David; Cedeño-Vázquez, José Rogelio; Forstner, Michael R J; Densmore, Llewellyn D

    2008-12-01

    Detecting and quantifying hybridization between endangered or threatened taxa can provide valuable information with regards to conservation and management strategies. Hybridization between members of the genus Crocodylus has been known to occur in captivity and in some wild populations. We tested for hybridization among wild populations of American crocodile (C. acutus) and Morelet's crocodile (C. moreletii) in the Yucatan Peninsula by comparing Bayesian assignment tests, based on microsatellite data, to mitochondrial and morphological assignments. Skin clips from 83 individuals were taken for genetic identification, and a total of 32 individuals (38.6%) exhibited some evidence of hybridization by combined morphological, mitochondrial and microsatellite analyses. The majority of hybrids were classified as F(2) hybrids and backcrosses to C. moreletii. Most of the introgression occurs in two national biosphere reserves located on the northern and eastern coasts of the Yucatan Peninsula. Preliminary tests did not find a significant decrease in hybridity across three life stages, thus far indicating a low level of selection against hybrids. Model-based analyses on multilocus genotypes of pure individuals returned little geographic partitioning in both C. acutus and C. moreletii. PMID:18800373

  10. Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves.

    PubMed

    Grap, Nadja J; Monzel, Anna S; Kohl, Tobias; Bleckmann, Horst

    2015-10-01

    Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude. PMID:26153334

  11. Integrating molecular, phenotypic and environmental data to elucidate patterns of crocodile hybridization in Belize.

    PubMed

    Hekkala, Evon R; Platt, Steven G; Thorbjarnarson, John B; Rainwater, Thomas R; Tessler, Michael; Cunningham, Seth W; Twomey, Christopher; Amato, George

    2015-09-01

    The genus Crocodylus comprises 12 currently recognized species, many of which can be difficult to differentiate phenotypically. Interspecific hybridization among crocodiles is known to occur in captivity and has been documented between some species in the wild. The identification of hybrid individuals is of importance for management and monitoring of crocodilians, many of which are Convention on International Trade in Endangered Species (CITES) listed. In this study, both mitochondrial and nuclear DNA markers were evaluated for their use in confirming a suspected hybrid zone between American crocodile (Crocodylus acutus) and Morelet's crocodile (Crocodylus moreletii) populations in southern Belize where individuals and nests exhibiting atypical phenotypic features had previously been observed. Patterns observed in both phenotypic and molecular data indicate possible behavioural and ecological characteristics associated with hybridization events. The results of the combined analyses found that the majority of suspected hybrid samples represent crosses between female C. acutus and male C. moreletii. Phenotypic data could statistically identify hybrids, although morphological overlap between hybrids and C. moreletii reduced reliability of identification based solely on field characters. Ecologically, C. acutus was exclusively found in saline waters, whereas hybrids and C. moreletii were largely absent in these conditions. A hypothesized correlation between unidirectional hybridization and destruction of C. acutus breeding habitats warrants additional research. PMID:26473062

  12. Integrating molecular, phenotypic and environmental data to elucidate patterns of crocodile hybridization in Belize

    PubMed Central

    Hekkala, Evon R.; Platt, Steven G.; Thorbjarnarson, John B.; Rainwater, Thomas R.; Tessler, Michael; Cunningham, Seth W.; Twomey, Christopher; Amato, George

    2015-01-01

    The genus Crocodylus comprises 12 currently recognized species, many of which can be difficult to differentiate phenotypically. Interspecific hybridization among crocodiles is known to occur in captivity and has been documented between some species in the wild. The identification of hybrid individuals is of importance for management and monitoring of crocodilians, many of which are Convention on International Trade in Endangered Species (CITES) listed. In this study, both mitochondrial and nuclear DNA markers were evaluated for their use in confirming a suspected hybrid zone between American crocodile (Crocodylus acutus) and Morelet’s crocodile (Crocodylus moreletii) populations in southern Belize where individuals and nests exhibiting atypical phenotypic features had previously been observed. Patterns observed in both phenotypic and molecular data indicate possible behavioural and ecological characteristics associated with hybridization events. The results of the combined analyses found that the majority of suspected hybrid samples represent crosses between female C. acutus and male C. moreletii. Phenotypic data could statistically identify hybrids, although morphological overlap between hybrids and C. moreletii reduced reliability of identification based solely on field characters. Ecologically, C. acutus was exclusively found in saline waters, whereas hybrids and C. moreletii were largely absent in these conditions. A hypothesized correlation between unidirectional hybridization and destruction of C. acutus breeding habitats warrants additional research. PMID:26473062

  13. Transplanting a unique allosteric effect from crocodile into human haemoglobin.

    PubMed

    Komiyama, N H; Miyazaki, G; Tame, J; Nagai, K

    1995-01-19

    Crocodiles are able to remain under water for more than one hour without surfacing to breathe and often kill their prey by drowning it. How do crocodiles stay under water for a long time? When they hold their breath, bicarbonate ions, the final product of respiration, accumulate and drastically reduce the oxygen affinity of haemoglobin, releasing a large fraction of haemoglobin-bound oxygen into the tissues. We have now located the bicarbonate-ion-binding site at the alpha 1 beta 2-subunit interface by making various human-crocodile chimaeric haemoglobins. Furthermore, we have been able to transplant the bicarbonate effect into human haemoglobin by replacing only a few residues, even though the amino-acid sequence identity between crocodile (Crocodylus niloticus) and human haemoglobins is only 68% for the alpha- and 51% for the beta-subunit. These results indicate that an entirely new function which enables species to adapt to a new environment could evolve in a protein by a relatively small number of amino-acid substitutions in key positions. PMID:7816138

  14. The probable role of cannibalism in spreading Trichinella papuae infection in a crocodile farm in Papua New Guinea.

    PubMed

    Owen, Ifor L; Awui, Columba; Langelet, Eric; Soctine, Wenda; Reid, Simon

    2014-07-14

    Between 2003 and 2007, 83 (50%) of 167 crocodiles (Crocodylus porosus) purchased as juveniles by a crocodile farm 3 or 4 years earlier from Kikori, Gulf Province, were found to be infected with Trichinella papuae. Between 2005 and 2007 infection was detected in a number of crocodiles at the farm obtained from six localities other than Kikori, as well as in a few animals born on the farm. Up to 2004, all juveniles at the farm, whether wild- or farm-born, were penned together; the practice was then stopped to prevent possible infection through cannibalism. The last infected animal from Kikori was seen in 2007, 4 years after the purchase of crocodiles from there ceased. The last non-Kikori infected crocodile was seen, also, in 2007. None of the 1972 crocodiles (comprising wild- and farm-born animals) tested from 2008 to 2013, using the digestion method, was infected with T. papuae. This indicates that infection of non-Kikori crocodiles was the result of cannibalism within the farm during the years up to 2004 when juvenile crocodiles were kept together, and that the farm is now free of the infection. PMID:24792746

  15. HNK-1 immunoreactivity during early morphogenesis of the head region in a nonmodel vertebrate, crocodile embryo.

    PubMed

    Kundrát, Martin

    2008-11-01

    The present study examines HNK-1 immunoidentification of a population of the neural crest (NC) during early head morphogenesis in the nonmodel vertebrate, the crocodile (Crocodylus niloticus) embryos. Although HNK-1 is not an exclusive NC marker among vertebrates, temporospatial immunoreactive patterns found in the crocodile are almost consistent with NC patterns derived from gene expression studies known in birds (the closest living relatives of crocodiles) and mammals. In contrast to birds, the HNK-1 epitope is immunoreactive in NC cells at the neural fold level in crocodile embryos and therefore provides sufficient base to assess early migratory events of the cephalic NC. I found that crocodile NC forms three classic migratory pathways in the head: mandibular, hyoid, and branchial. Further, I demonstrate that, besides this classic phenotype, there is also a forebrain-derived migratory population, which consolidates into a premandibular stream in the crocodile. In contrast to the closely related chick model, crocodilian premandibular and mandibular NC cells arise from the open neural tube suggesting that species-specific heterochronic behavior of NC may be involved in the formation of different vertebrate facial phenotypes. PMID:18668221

  16. HNK-1 immunoreactivity during early morphogenesis of the head region in a nonmodel vertebrate, crocodile embryo

    NASA Astrophysics Data System (ADS)

    Kundrát, Martin

    2008-11-01

    The present study examines HNK-1 immunoidentification of a population of the neural crest (NC) during early head morphogenesis in the nonmodel vertebrate, the crocodile ( Crocodylus niloticus) embryos. Although HNK-1 is not an exclusive NC marker among vertebrates, temporospatial immunoreactive patterns found in the crocodile are almost consistent with NC patterns derived from gene expression studies known in birds (the closest living relatives of crocodiles) and mammals. In contrast to birds, the HNK-1 epitope is immunoreactive in NC cells at the neural fold level in crocodile embryos and therefore provides sufficient base to assess early migratory events of the cephalic NC. I found that crocodile NC forms three classic migratory pathways in the head: mandibular, hyoid, and branchial. Further, I demonstrate that, besides this classic phenotype, there is also a forebrain-derived migratory population, which consolidates into a premandibular stream in the crocodile. In contrast to the closely related chick model, crocodilian premandibular and mandibular NC cells arise from the open neural tube suggesting that species-specific heterochronic behavior of NC may be involved in the formation of different vertebrate facial phenotypes.

  17. Spatial and stage-structured population model of the American crocodile for comparison of comprehensive Everglades Restoration Plan (CERP) alternatives

    USGS Publications Warehouse

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2010-01-01

    As part of the U.S. Geological Survey Priority Ecosystems Science (PES) initiative to provide the ecological science required during Everglades restoration, we have integrated current regional hydrologic models with American crocodile (Crocodylus acutus) research and monitoring data to create a model that assesses the potential impact of Comprehensive Everglades Restoration Plan (CERP) efforts on the American crocodile. A list of indicators was created by the Restoration Coordination and Verification (RECOVER) component of CERP to help determine the success of interim restoration goals. The American crocodile was established as an indicator of the ecological condition of mangrove estuaries due to its reliance upon estuarine environments characterized by low salinity and adequate freshwater inflow. To gain a better understanding of the potential impact of CERP restoration efforts on the American crocodile, a spatially explicit crocodile population model has been created that has the ability to simulate the response of crocodiles to various management strategies for the South Florida ecosystem. The crocodile model uses output from the Tides and Inflows in the Mangroves of the Everglades (TIME) model, an application of the Flow and Transport in a Linked Overland/Aquifer Density Dependent System (FTLOADDS) simulator. TIME has the capability to link to the South Florida Water Management Model (SFWMM), which is the primary regional tool used to assess CERP restoration scenarios. A crocodile habitat suitability index and spatial parameter maps that reflect salinity, water depth, habitat, and nesting locations are used as driving functions to construct crocodile finite rate of increase maps under different management scenarios. Local stage-structured models are integrated with a spatial landscape grid to display crocodile movement behavior in response to changing environmental conditions. Restoration efforts are expected to affect salinity levels throughout the habitat of

  18. Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes

    PubMed Central

    2012-01-01

    The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described. PMID:22293439

  19. Retinal projections in two crocodilian species, Caiman crocodilus and Crocodylus niloticus.

    PubMed

    Derobert, Y; Médina, M; Rio, J P; Ward, R; Repérant, J; Marchand, M J; Miceli, D

    1999-08-01

    The retinal projections of Caiman crocodilus and Crocodylus niloticus were investigated by means of the orthograde axonal transport of either rhodamine beta-isothiocyanate or tritiated proline. In these two species, each tracer revealed contralateral retinal projections to three hypothalamic regions (subventricular gray matter, nucleus suprachiasmaticus, and area optica hypothalami lateralis), five thalamic regions (nuclei ovalis, dorsolateralis anterior, ventrolateralis and ventrobasalis, and lateral geniculate complex, of which six subcomponents can be distinguished), six pretectal regions (nuclei posterodorsalis, lentiformis mesencephali, griseus tectalis, geniculatus pretectalis, area optica commissurae posterior and area optica pretectalis lateroventralis), six outermost layers of the optic tectum, and the nucleus opticus tegmenti. Weak ipsilateral retinal projections have been observed in two hypothalamic nuclei and in the nucleus opticus tegmenti. Comparative analysis with other data show that the contralateral retinal projections of crocodiles are considerably more reptilian than avian. Moreover, crocodiles share with birds an extremely poor contingent of ipsilateral retinal projections. PMID:10424875

  20. Prenatal development of Crocodylus niloticus niloticus Laurenti, 1768.

    PubMed

    Peterka, Miroslav; Sire, Jean Yves; Hovorakova, Maria; Prochazka, Jan; Fougeirol, Luc; Peterkova, Renata; Viriot, Laurent

    2010-07-15

    Prenatal development in crocodilians represents a very interesting model for comparative studies. As the speed of prenatal development of crocodilians varies depending on incubation conditions, the staging of embryos and fetuses is a very important prerequisite for data correlation. To establish a background for future developmental studies on Crocodylus niloticus, we characterized its prenatal development in a collection comprising 169 animals during embryonic/incubation days 9-70. The characteristics included external morphology, head morphometry, and wet body weight determined before fixation. We documented the external morphology of prenatal Nile crocodiles in a large collection of photographs and described landmarks during the morphogenesis of the head, face and limbs. In the development of the facial processes (medial nasal, lateral nasal, maxillary), three phases could be distinguished: union, separation, reunion. At the free jaw margin, a regular series of prominences was present. The outer aspect of a prominence gave rise to a labial scale, the inner aspect to a tooth. In contrast to mammals (humans and mice), the hindlimbs of C. niloticus developed faster than the forelimbs. We also determined changes in basic measures of the head and of the wet body weight. Both morphological and morphometric characteristics showed an apparent inter-individual variability among animals of the same age. This variability decreased among animals of a similar body weight (irrespective of their age). Body weight can be considered as the most representative and complex parameter for crocodile staging reflecting the overall growth of a whole embryo/fetus. PMID:20073049

  1. Mercury in Morelet's crocodile eggs from northern Belize.

    PubMed

    Rainwater, T R; Adair, B M; Platt, S G; Anderson, T A; Cobb, G P; McMurry, S T

    2002-04-01

    Recent studies have examined mercury accumulation in crocodilians. However, though most researchers have focused on tissue concentrations, few have examined mercury levels in crocodilian eggs. In July 1995, we analyzed mercury in 31 nonviable Morelet's crocodile ( Crocodylus moreletii) eggs collected from eight nests across three localities in northern Belize. All eggs were found to contain mercury. Based on an individual egg basis, mean concentration of mercury for all three localities was among the lowest reported for any crocodilian species. When localities were examined separately, mean concentrations for Laguna Seca and Gold Button Lagoon were comparable to those observed in other studies, and the mean for Sapote Lagoon was the lowest ever reported. Based on mean nest concentrations, mercury in eggs from Laguna Seca was approximately two- and tenfold higher than for Gold Button Lagoon and Sapote Lagoon, respectively. Variability in mercury concentrations among localities is likely the result of site-specific differences in mercury input, bioavailabilty, and bioaccumulation. Mercury concentrations were relatively uniform in eggs from the same nest and among nests from the same localities. The presence of mercury in Morelet's crocodile eggs suggests exposure in adult females, developing embryos, and neonates. However, crocodiles in these areas show no overt signs of mercury toxicity, and no indication of population decline is evident. A paucity of data on the effects of mercury on crocodilians precludes meaningful speculation as to the biological significance of tissue and egg concentrations. Controlled laboratory studies and long-term population monitoring are needed to address these questions. PMID:11910460

  2. Evaluating effects of Everglades restoration on American crocodile populations in south Florida using a spatially-explicit, stage-based population model

    USGS Publications Warehouse

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2014-01-01

    The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.

  3. Hybridization between Crocodylus acutus and Crocodylus moreletii in the Yucatan Peninsula: I. Evidence from mitochondrial DNA and morphology.

    PubMed

    Cedeño-Vázquez, José Rogelio; Rodriguez, David; Calmé, Sophie; Ross, James Perran; Densmore, Llewellyn D; Thorbjarnarson, John B

    2008-12-01

    The American crocodile (Crocodylus acutus) and the Morelet's crocodile (C. moreletii) are broadly sympatric in Belize and Mexico. The presence of morphologically anomalous individuals in the overlapping range area suggests possible hybridization between these species. Analysis of 477 base pairs of the mitochondrial tRNA(Pro)-tRNA(Phe)-Dloop region revealed the presence of pure C. acutus (N=43) and C. moreletii (N=56), as well as a high proportion of interspecific hybrids (N=17, 14.6%) in the Yucatan Peninsula, Mexico. Although all individuals could be assigned to one species or other based on phenotypic characters, some had been characterized as potential hybrids in the field by anomalous scale counts. The hybridization zone lies along the area of sympatry between C. acutus and C. moreletii investigated in this study, but extends further inland if hybrid localities from Belize are included. Hybridization in the Yucatan Peninsula is bidirectional, which indicates considerably more genetic contact between these species than previously recognized, and is probably more detrimental to the genetic integrity of smaller C. acutus populations. A more intensive study of the pattern of hybridization is warranted and supports continued classification of C. acutus as a critically threatened species in the Yucatan Peninsula. PMID:18626922

  4. Saltwater icephobicity: Influence of surface chemistry on saltwater icing

    PubMed Central

    Carpenter, Katherine; Bahadur, Vaibhav

    2015-01-01

    Most studies on icephobicity focus on ice formation with pure water. This manuscript presents studies to understand the influence of surfaces on saltwater ice nucleation and propagation. Experiments are conducted to quantify the influence of surface chemistry on saltwater ice nucleation and to understand the utility of superhydrophobic surfaces for saltwater icephobicity. These experiments are conducted with pure water and two sodium chloride solutions, which represent the salinity of seawater and briny produced water. It is seen that the presence of salt slows down the ice front propagation velocity significantly. Saltwater droplet impact dynamics on superhydrophobic surfaces are also different from pure water. Saltwater droplets retract more and a greater fraction of impacting liquid is repelled from the superhydrophobic surface. It is seen that the greater bounciness of saltwater droplets is a result of slower ice nucleation propagation kinetics. These experiments indicate that superhydrophobic surfaces will have better resistance to impact icing with saltwater than pure water and can remain useful at temperatures as low as −40 °C. Overall, this work is a starting point for further studies on heterogeneous nucleation in saltwater and serves as a bridge between the widely studied freshwater icephobic surfaces and saltwater-related applications. PMID:26626958

  5. Saltwater icephobicity: Influence of surface chemistry on saltwater icing

    NASA Astrophysics Data System (ADS)

    Carpenter, Katherine; Bahadur, Vaibhav

    2015-12-01

    Most studies on icephobicity focus on ice formation with pure water. This manuscript presents studies to understand the influence of surfaces on saltwater ice nucleation and propagation. Experiments are conducted to quantify the influence of surface chemistry on saltwater ice nucleation and to understand the utility of superhydrophobic surfaces for saltwater icephobicity. These experiments are conducted with pure water and two sodium chloride solutions, which represent the salinity of seawater and briny produced water. It is seen that the presence of salt slows down the ice front propagation velocity significantly. Saltwater droplet impact dynamics on superhydrophobic surfaces are also different from pure water. Saltwater droplets retract more and a greater fraction of impacting liquid is repelled from the superhydrophobic surface. It is seen that the greater bounciness of saltwater droplets is a result of slower ice nucleation propagation kinetics. These experiments indicate that superhydrophobic surfaces will have better resistance to impact icing with saltwater than pure water and can remain useful at temperatures as low as -40 °C. Overall, this work is a starting point for further studies on heterogeneous nucleation in saltwater and serves as a bridge between the widely studied freshwater icephobic surfaces and saltwater-related applications.

  6. Crocodiles in the Sahara Desert: An Update of Distribution, Habitats and Population Status for Conservation Planning in Mauritania

    PubMed Central

    Brito, José C.; Martínez-Freiría, Fernando; Sierra, Pablo; Sillero, Neftalí; Tarroso, Pedro

    2011-01-01

    Background Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20th century, increased aridity combined with human persecution led to local extinction. Knowledge on distribution, occupied habitats, population size and prey availability is scarce in most populations. This study evaluates the status of Saharan crocodiles and provides new data for Mauritania to assist conservation planning. Methodology/Principal Findings A series of surveys in Mauritania detected crocodile presence in 78 localities dispersed across 10 river basins and most tended to be isolated within river basins. Permanent gueltas and seasonal tâmoûrts were the most common occupied habitats. Crocodile encounters ranged from one to more than 20 individuals, but in most localities less than five crocodiles were observed. Larger numbers were observed after the rainy season and during night sampling. Crocodiles were found dead in between water points along dry river-beds suggesting the occurrence of dispersal. Conclusion/Significance Research priorities in Chad and Egypt should focus on quantifying population size and pressures exerted on habitats. The present study increased in by 35% the number of known crocodile localities in Mauritania. Gueltas are crucial for the persistence of mountain populations. Oscillations in water availability throughout the year and the small dimensions of gueltas affect biological traits, including activity and body size. Studies are needed to understand adaptation traits of desert populations. Molecular analyses are needed to quantify genetic variability, population sub-structuring and effective population size, and detect the occurrence of gene flow. Monitoring is needed to detect demographical and genetical trends in completely isolated populations. Crocodiles are apparently vulnerable during dispersal events. Awareness campaigns focusing on the vulnerability and

  7. Plasma vitellogenin in Morelet's crocodiles from contaminated habitats in northern Belize.

    PubMed

    Rainwater, Thomas R; Selcer, Kyle W; Nespoli, Lisa M; Finger, Adam G; Ray, David A; Platt, Steven G; Smith, Philip N; Densmore, Llewellyn D; Anderson, Todd A; McMurry, Scott T

    2008-05-01

    Vitellogenin induction has been widely used as a biomarker of endocrine disruption in wildlife, but few studies have investigated its use in wild reptiles living in contaminated habitats. This study examined vitellogenin induction in Morelet's crocodiles (Crocodylus moreletii) from wetlands in northern Belize contaminated with organochlorine (OC) pesticides. Vitellogenin was measured in 381 crocodile plasma samples using a vitellogenin ELISA previously developed for this species. Vitellogenin was detected in nine samples, all from adult females sampled during the breeding season. Males and juvenile females did not contain detectable levels of vitellogenin; however, many of these animals contained OC pesticides in their caudal scutes, confirming contaminant exposure. The lack of a vitellogenic response in these animals may be attributable to several factors related to the timing and magnitude of exposure to endocrine-disrupting chemicals and should not be interpreted as an absence of other contaminant-induced biological responses. PMID:17826876

  8. Fatal crocodile attack.

    PubMed

    Chattopadhyay, Saurabh; Shee, Biplab; Sukul, Biswajit

    2013-11-01

    Attacks on human beings by various animals leading to varied types of injuries and even death in some cases are not uncommon. Crocodile attacks on humans have been reported from a number of countries across the globe. Deaths in such attacks are mostly due to mechanical injuries or drowning. Bites by the crocodiles often cause the limbs to be separated from the body. The present case refers to an incident of a fatal attack by a crocodile on a 35 years old female where only the mutilated head of the female was recovered. Multiple lacerated wounds over the face and scalp along with fracture of the cranial bones was detected on autopsy. Two distinct bite marks in the form of punched in holes were noted over the parietal and frontal bones. Injuries on the head with its traumatic amputation from the body were sufficient to cause death. However, the presence of other fatal injuries on the unrecovered body parts could not be ruled out. PMID:24237838

  9. beta-Keratins in crocodiles reveal amino acid homology with avian keratins.

    PubMed

    Ye, Changjiang; Wu, Xiaobing; Yan, Peng; Amato, George

    2010-03-01

    The DNA sequences encoding beta-keratin have been obtained from Marsh Mugger (Crocodylus palustris) and Orinoco Crocodiles (Crocodylus intermedius). Through the deduced amino acid sequence, these proteins are rich in glycine, proline and serine. The central region of the proteins are composed of two beta-folded regions and show a high degree of identity with beta-keratins of aves and squamates. This central part is thought to be the site of polymerization to build the framework of beta-keratin filaments. It is believed that the beta-keratins in reptiles and birds share a common ancestry. Near the C-terminal, these beta-keratins contain a peptide rich in glycine-X and glycine-X-X, and the distinctive feature of the region is some 12-amino acid repeats, which are similar to the 13-amino acid repeats in chick scale keratin but absent from avian feather keratin. From our phylogenetic analysis, the beta-keratins in crocodile have a closer relationship with avian keratins than the other keratins in reptiles. PMID:19266314

  10. A giant crocodile in the Dubois Collection from the Pleistocene of Kali Gedeh (Java).

    PubMed

    Delfino, Massimo; De Vos, John

    2014-03-01

    The fauna of the Pleistocene Homo-bearing sites of Java has been well known for more than a century. A recent revision of the crocodylian remains confirmed both the validity of Gavialis bengawanicus and the synonymization of Crocodylus ossifragus with C. siamensis. Here we report on a still unpublished crocodylian specimen collected by Eugene Dubois in the latest Early Pleistocene of Kali Gedeh that can be tentatively referred to the genus Crocodylus. The size of the specimen, the approximately 1 m long lower jaw in particular, indicated that this crocodile attained a total length of approximately 6 or 7 m. Along with specimens from the Plio-Pleistocene of Africa, this material provides evidence for gigantism in Crocodylus. It is not clear whether or not the 'temperature-size rule' applies to fossil crocodylians, but due to the growing interest in predicting future temperature-related size changes of the extant organisms, it would be interesting to study in detail the past reaction to temperature changes of crocodylians and other terrestrial ectothermic animals. PMID:24673759

  11. Metals and organochlorine pesticides in caudal scutes of crocodiles from Belize and Costa Rica.

    PubMed

    Rainwater, Thomas R; Wu, Ted H; Finger, Adam G; Cañas, Jaclyn E; Yu, Lu; Reynolds, Kevin D; Coimbatore, Gopal; Barr, Brady; Platt, Steven G; Cobb, George P; Anderson, Todd A; McMurry, Scott T

    2007-02-01

    Despite high animal diversity in the Neotropics and the largely unregulated use and disposal of pesticides and industrial chemicals in Central America, few data exist regarding accumulation of environmental contaminants in Central American wildlife. In this study we examined accumulation of metals and organochlorine (OC) pesticides in caudal scutes of crocodiles from Belize and Costa Rica. Scutes from Morelet's crocodiles (Crocodylus moreletii) from two sites in northern Belize were analyzed for metals, and scutes from American crocodiles (C. acutus) from one site in Costa Rica were analyzed for metals and OC pesticides. All scutes (n=25; one scute from each of 25 individuals) contained multiple contaminants. Mercury was the predominant metal detected, occurring in all scutes examined from both species. Other metals detected include cadmium, copper, lead, and zinc. American crocodile scutes from Costa Rica contained multiple OC pesticides, including endrin, methoxychlor, p,p'-DDE, and p,p'-DDT, all of which occurred in 100% of scutes analyzed (n=6). Mean metal and OC concentrations varied in relation to those previously reported in crocodilian scutes from other localities in North, Central, and South America. OC concentrations in American crocodile scutes were generally higher than those previously reported for other Costa Rican wildlife. Currently, caudal scutes may serve as general, non-lethal indicators of contaminant accumulation in crocodilians and their areas of occurrence. However, a better understanding of the relationships between pollutant concentrations in scutes, internal tissues, and environmental matrices at sample collection sites are needed to improve the utility of scutes in future ecotoxicological investigations. PMID:17182086

  12. Presumptive FMRF-amide-like immunoreactive retinopetal fibres in Crocodylus niloticus.

    PubMed

    Médina, Monique; Repérant, Jacques; Ward, Roger; Miceli, Dom

    2004-10-29

    A small contingent of 30-50 of centrifugal visual fibres, showing FMRF-amide-like immunoreactivity, has been identified in C. niloticus; these fibres extend from the chiasmatic region into the retina. They do not take the marginal optic tract, but pass medially to the chiasmatic fascicles, from the preoptic region. The cells of origin of these fibres have not been identified. However, none of the retinopetal neurons of the brainstem [M. Medina, J. Reperant, R. Ward, D. Miceli, Centrifugal visual system of Crocodylus niloticus : a hodological, histochemical and immunocytochemical study, J. Comp. Neurol. 468 (2004) 65-85], labelled by retrograde transport of rhodamine beta-isothiocyanate after intraocular injection of this tracer, show FMRF-amide-like immunoreactivity; neither are any of the FMRF-amide-like immunopositive neurons in the crocodile brain, particularly those of the complex involving the terminal nerve and the septo-preoptic region, labelled by rhodamine after its intraocular injection. PMID:15464765

  13. Organochlorine pesticides in chorioallantoic membranes of Morelet's crocodile eggs from belize.

    PubMed

    Pepper, Christopher B; Rainwater, Thomas R; Platt, Steven G; Dever, Jennifer A; Anderson, Todd A; McMurry, Scott T

    2004-07-01

    Recent studies examined the utility of the chorioallantoic membrane (CAM) as a nonlethal, noninvasive indicator of environmental contaminant exposure in oviparous wildlife. The CAM is a highly vascularized extraembryonic membrane that functions as a site for respiration, nutrient transport, and waste storage during embryonic development. After hatching, the CAM is usually discarded with the eggshell and can be used for chemical residue analysis. Chorioallantoic membranes have been used successfully to examine contaminant exposure and predict chemical concentrations in multiple species of birds and reptiles. In this study, we examined organochlorine (OC) pesticide concentrations in CAMs from eggs of Morelet's crocodiles (Crocodylus moreletii) from northern Belize. Multiple OCs were detected in crocodile CAMs, including aldrin, dieldrin, endrin, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene (DDE), heptachlor, lindane, and methoxychlor. Number and concentrations of OC compounds in CAMs were variable. The most prevalent contaminant detected was DDE, which occurred in 69% of CAMs, with concentrations ranging from 0.3 parts per billion (ppb) to 17.0 ppb. The OC burdens in crocodile CAMs confirm contamination of eggs and suggest exposure in embryos and maternal females. These results further support the use of CAMs as qualitative indicators of OC exposure in oviparous wildlife. The efficacy of this sampling technique in the field will depend on the logistics and cost associated with CAM collection and the specific life history traits of the wildlife species. PMID:15465717

  14. Sexual size dimorphism and allometric growth of Morelet's crocodiles in captivity.

    PubMed

    Barrios-Quiroz, Gabriel; Casas-Andreu, Gustavo; Escobedo-Galván, Armando H

    2012-03-01

    Few studies have conducted morphological analyses of crocodilians, and little information exists on differences between size-classes and sexes in Neotropical crocodilians. In this study, we measured nine morphological traits in 121 captive Morelet's crocodiles Crocodylus moreletii (81 females and 40 males). Our results revealed that individuals < 2 m total length do not exhibit sexual dimorphism in morphometric characteristics. However, for crocodiles over 2 m in length, males were significantly larger than females in terms of dorsal-cranial length, cranial width, snout width and snout-ventral length. In general, morphological traits demonstrated a strongly significant relationship with total length at the smaller size class of 150-200 cm length. However, in the highest size class of 250-300 cm length (large adult males), morphological traits were no longer significantly related with total length. Male crocodiles demonstrated allometric growth of cranial morphology with significantly greater increase in cranial width, snout width, and mid-snout width relative to total length at higher size classes. Morphological dimorphism and allometric growth may be associated with adaptive strategies for reproductive success. PMID:22379988

  15. Reassessment of genome size in turtle and crocodile based on chromosome measurement by flow karyotyping: close similarity to chicken.

    PubMed

    Kasai, Fumio; O'Brien, Patricia C M; Ferguson-Smith, Malcolm A

    2012-08-23

    The genome size in turtles and crocodiles is thought to be much larger than the 1.2 Gb of the chicken (Gallus gallus domesticus, GGA), according to the animal genome size database. However, GGA macrochromosomes show extensive homology in the karyotypes of the red eared slider (Trachemys scripta elegans, TSC) and the Nile crocodile (Crocodylus niloticus, CNI), and bird and reptile genomes have been highly conserved during evolution. In this study, size and GC content of all chromosomes are measured from the flow karyotypes of GGA, TSC and CNI. Genome sizes estimated from the total chromosome size demonstrate that TSC and CNI are 1.21 Gb and 1.29 Gb, respectively. This refines previous overestimations and reveals similar genome sizes in chicken, turtle and crocodile. Analysis of chromosome GC content in each of these three species shows a higher GC content in smaller chromosomes than in larger chromosomes. This contrasts with mammals and squamates in which GC content does not correlate with chromosome size. These data suggest that a common ancestor of birds, turtles and crocodiles had a small genome size and a chromosomal size-dependent GC bias, distinct from the squamate lineage. PMID:22491763

  16. Reassessment of genome size in turtle and crocodile based on chromosome measurement by flow karyotyping: close similarity to chicken

    PubMed Central

    Kasai, Fumio; O'Brien, Patricia C. M.; Ferguson-Smith, Malcolm A.

    2012-01-01

    The genome size in turtles and crocodiles is thought to be much larger than the 1.2 Gb of the chicken (Gallus gallus domesticus, GGA), according to the animal genome size database. However, GGA macrochromosomes show extensive homology in the karyotypes of the red eared slider (Trachemys scripta elegans, TSC) and the Nile crocodile (Crocodylus niloticus, CNI), and bird and reptile genomes have been highly conserved during evolution. In this study, size and GC content of all chromosomes are measured from the flow karyotypes of GGA, TSC and CNI. Genome sizes estimated from the total chromosome size demonstrate that TSC and CNI are 1.21 Gb and 1.29 Gb, respectively. This refines previous overestimations and reveals similar genome sizes in chicken, turtle and crocodile. Analysis of chromosome GC content in each of these three species shows a higher GC content in smaller chromosomes than in larger chromosomes. This contrasts with mammals and squamates in which GC content does not correlate with chromosome size. These data suggest that a common ancestor of birds, turtles and crocodiles had a small genome size and a chromosomal size-dependent GC bias, distinct from the squamate lineage. PMID:22491763

  17. Redescription and molecular characterisation of Dujardinascaris madagascariensis and a note on D. dujardini (Nematoda: Heterocheilidae), parasites of Crocodylus niloticus, with a key to Dujardinascaris spp. in crocodilians.

    PubMed

    Mašová, Šárka; Baruš, Vlastimil; Seifertová, Mária; Malala, John; Jirků, Miloslav

    2014-01-01

    An examination of one specimen of Nile crocodile, Crocodylus niloticus (Laurenti, 1768), from Lake Turkana (Kenya), revealed the presence of two ascaridoid nematodes belonging to the genus Dujardinascaris Baylis, 1947. Dujardinascaris madagascariensis Chabaud & Caballero, 1966 was studied by scanning electron microscopy, redescribed, and differentiated from D. dujardini (Travassos, 1920). Dujardinascaris madagascariencsis is the second of the genus to be sequenced. An internal fragment of the small ribosomal subunit and nuclear ribosomal DNA internal transcribed spacer 2 region were amplified--the slowly evolving 18S gene region was used for phylogenetic analysis. Molecular data confirmed affinity of D. madagascariensis to the family Heterocheilidae and revealed its closest relationship with D. waltoni. A key to the species of Dujardinascaris parasitizing crocodiles is provided. PMID:25544522

  18. Purification and characterization of antioxidant peptides from leukocyte extract of Crocodylus siamensis.

    PubMed

    Theansungnoen, Tinnakorn; Yaraksa, Nualyai; Daduang, Sakda; Dhiravisit, Apisak; Thammasirirak, Sompong

    2014-02-01

    Antioxidant peptides were isolated from the leukocyte extract of the Siamese crocodile, Crocodylus siamensis. Crocodile leukocyte was extracted by a combination of methods including freeze-thawing, acetic acid extraction and homogenization. The peptides in the leukocyte extract were purified by anion exchange chromatography and reversed phase-high performance liquid chromatography. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay was used to evaluate the antioxidant activity of the elution peaks at each purification step. As a result, there were two purified peptides exhibiting strong antioxidant activity in reducing free radicals on DPPH molecules. The amino acid sequences of these peptides were determined by LC-MS/MS as TDVLGLPAK (912.5 Da) and DPNAALPAGPR (1,148.6 Da), and their IC₅₀ values were 153.4 and 95.7 μM, respectively. The results of this study therefore indicate that leukocyte extract of C. siamensis contains peptides with antioxidant activity which could be used as a novel antioxidant. PMID:24374428

  19. Extensive homology of chicken macrochromosomes in the karyotypes of Trachemys scripta elegans and Crocodylus niloticus revealed by chromosome painting despite long divergence times.

    PubMed

    Kasai, F; O'Brien, P C M; Martin, S; Ferguson-Smith, M A

    2012-01-01

    We report extensive chromosome homology revealed by chromosome painting between chicken (Gallus gallus domesticus, GGA, 2n = 78) macrochromosomes (representing 70% of the chicken genome) and the chromosomes of a turtle, the red-eared slider (Trachemys scripta elegans, TSC, 2n = 50), and the Nile crocodile (Crocodylus niloticus, CNI, 2n = 32). Our data show that GGA1-8 arms seem to be conserved in the arms of TSC chromosomes, GGA1-2 arms are separated and homologous to CNI1p, 3q, 4q and 5q. In addition to GGAZ homologues in our previous study, large-scale GGA autosome syntenies have been conserved in turtle and crocodile despite hundreds of millions of years divergence time. Based on phylogenetic hypotheses that crocodiles diverged after the divergence of birds and turtles, our results in CNI suggest that GGA1-2 and TSC1-2 represent the ancestral state and that chromosome fissions followed by fusions have been the mechanisms responsible for the reduction of chromosome number in crocodiles. PMID:22572532

  20. Reelin expression during embryonic brain development in Crocodylus niloticus.

    PubMed

    Tissir, F; Lambert De Rouvroit, C; Sire, J-Y; Meyer, G; Goffinet, A M

    2003-03-10

    The expression of reelin mRNA and protein was studied during embryonic brain development in the Nile crocodile Crocodylus niloticus, using in situ hybridization and immunohistochemistry. In the forebrain, reelin was highly expressed in the olfactory bulb, septal nuclei, and subpial neurons in the marginal zone of the cerebral cortex, dorsal ventricular ridge, and basal forebrain. At early stages, reelin mRNA was also detected in subventricular zones. In the diencephalon, the ventral lateral geniculate nuclei and reticular nuclei were strongly positive, with moderate expression in the habenula and focal expression in the hypothalamus. High expression levels were noted in the retina, the tectum, and the external granule cell layer of the cerebellum. In the brainstem, there was a high level of signal in cochleovestibular, sensory trigeminal, and some reticular nuclei. No expression was observed in the cortical plate or Purkinje cells. Comparison with reelin expression during brain development in mammals, birds, turtles, and lizards reveals evolutionarily conserved, homologous features that presumably define the expression profile in stem amniotes. The crocodilian cortex contains subpial reelin-positive cells that are also p73 positive, suggesting that they are homologous to mammalian Cajal-Retzius cells, although they express the reelin gene less intensely. Furthermore, the crocodilian cortex does not contain the subcortical reelin-positive cells that are typical of lizards but expresses reelin in subventricular zones at early stages. These observations confirm that reelin is prominently expressed in many structures of the embryonic brain in all amniotes and further emphasize the unique amplification of reelin expression in mammalian Cajal-Retzius cells and its putative role in the evolution of the cerebral cortex. PMID:12541309

  1. Saltwater upconing zone of influence

    NASA Astrophysics Data System (ADS)

    Jakovovic, Danica; Werner, Adrian D.; de Louw, Perry G. B.; Post, Vincent E. A.; Morgan, Leanne K.

    2016-08-01

    In this study, we define and characterize the saltwater upconing zone of influence (SUZI). The SUZI is the region around a pumping well within which significant rise in the saltwater-freshwater interface occurs. While the zone of influence of a pumping well can be clearly defined in terms of hydraulics (e.g., drawdown), the SUZI has not been recognised and characterised, despite its importance for groundwater decision-making in coastal regions. We explore the SUZI under various conditions and compare common methods of investigation using both axisymmetric (1D and 2D vertical cross-section) and 3D simulations of saltwater upconing at the field scale, based on a combination of numerical and analytical approaches. The SUZI was found to be dependent on the relative magnitudes of pumping, regional flow, distance of the well from the coast, and position of the well above the interface, as expected. The three-dimensional coastal setting simulations revealed an asymmetric shape of the lateral extent of the SUZI, which is largest in the direction parallel to the coast. This occurs because the ocean and the inland extent of the seawater wedge limit the propagation of the SUZI perpendicular to the coast. Predictions of the SUZI using the Ghyben-Herzberg approximation, including cases where sloping interfaces occur (i.e., in contrast to the artificiality of horizontal interfaces used in axisymmetric approaches), provide reasonable first approximations of the SUZI. Numerical modelling of dispersive upconing in the 3D inclined interface case is influenced by practical limits to the model domain size and grid resolution. For example, the no-flow boundary condition at 1500 m from the pumping well elongates the SUZI in the direction parallel to the coast. This study extends previous concepts of well interference, which have previously been based on hydraulics only, by introducing the SUZI and characterising its extent, with consideration given to differences in commonly adopted

  2. Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

    PubMed Central

    Milián-García, Y; Ramos-Targarona, R; Pérez-Fleitas, E; Sosa-Rodríguez, G; Guerra-Manchena, L; Alonso-Tabet, M; Espinosa-López, G; Russello, M A

    2015-01-01

    Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value. PMID:25335559

  3. Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation.

    PubMed

    Milián-García, Y; Ramos-Targarona, R; Pérez-Fleitas, E; Sosa-Rodríguez, G; Guerra-Manchena, L; Alonso-Tabet, M; Espinosa-López, G; Russello, M A

    2015-03-01

    Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value. PMID:25335559

  4. First description of the male and redescription of the female of Paratrichosoma recurvum (Nematoda: Capillariidae), a skin-invading parasite of crocodiles in Mexico.

    PubMed

    Moravec, F; Vargas-Vázquez, J

    1998-06-01

    The first description of the male and a redescription of the female of the nematode Paratrichosoma recurvum (Solger, 1877), a parasite of the abdominal skin of crocodiles, are presented on the basis of specimens collected from Crocodilus moreletii Duméril et Bibron from the Lagoon of Celestún, Yucatan, Mexico. The morphology of P. recurvum proved to be very similar to that of the only other congeneric species, P. crocodylus Ashford et Muller, 1978, but the former differed from the latter in having distinctly protruding polar plugs on eggs, reduced mesenchymal cells at the esophagointestinal junction, and a smooth spicular surface as well as in geographic distribution. The finding of P. recurvum in C. moreletii represents a new host record. Paratrichosoma spp. appear to be widely distributed in tropical countries of different continents and may be of economic importance for crocodile farms. PMID:9660141

  5. Commercial crocodile farming in Botswana.

    PubMed

    Dzoma, B M; Sejoe, S; Segwagwe, B V E

    2008-06-01

    A survey-based study was carried out to assess the state of crocodile farming in Botswana. A prepared, structured questionnaire was dispatched to crocodile farmers based on a directory provided by the Fisheries section of the Department of Wildlife and National Parks in the Ministry of Environment, Wildlife and National Parks. The oldest farm was established in 1986. An average of three farms have been in operation since then, all of which obtained their stock from the Okavango and Thamalakane rivers in Botswana. The current stock averages 5,419 animals as follows: breeders 4%, hatchlings 56%, and growers 40%. The average clutch size and average hatchability were 47 eggs/clutch and 67% respectively. Mortality among hatchings and growers averaged 8.3% up to 12 weeks of age. Only one farm encountered some problems with Salmonella and fungal infections of the belly. Raw skins are sold to South Africa as a result of the absence of a tannery. Crocodile farming should be encouraged in Botswana since a good market for crocodile products already exists. PMID:18509947

  6. Crocodile Technology. [CD-ROM].

    ERIC Educational Resources Information Center

    2000

    This high school physics computer software resource is a systems and control simulator that covers the topics of electricity, electronics, mechanics, and programming. Circuits can easily be simulated on the screen and electronic and mechanical components can be combined. In addition to those provided in Crocodile Technology, a student can create…

  7. The American Crocodile in Biscayne Bay, Florida

    USGS Publications Warehouse

    Cherkiss, Michael S.; Romañach, Stephanie S.; Mazzotti, Frank J.

    2011-01-01

    Intensive crocodile monitoring programs conducted during the late 1970s and early 1980s in southern Florida resulted in an optimistic outlook for recovery of the protected species population. However, some areas with suitable crocodile habitat were not investigated, such as Biscayne Bay and the mainland shorelines of Barnes and Card Sounds. The objective of our study was to determine status and habitat use of crocodiles in the aforementioned areas. Spotlight and nesting surveys were conducted from September 1996 to December 2005. The results revealed annual increases in the number of crocodiles. Crocodiles preferred protected habitats such as canals and ponds. Fewer crocodiles were observed in higher salinity water. The distribution and abundance of crocodilians in estuaries is directly dependent on timing, amount, and location of freshwater delivery, providing an opportunity to integrate habitat enhancement with ongoing ecosystem restoration and management activities.

  8. A diagnosis of crocodile feeding traces on larger mammal bone, with fossil examples from the Plio-Pleistocene Olduvai Basin, Tanzania.

    PubMed

    Njau, Jackson K; Blumenschine, Robert J

    2006-02-01

    Neotaphonomic studies have determined the patterns of bone damage created by larger mammalian carnivores when consuming mammalian carcasses. Typically, mammalian carnivores gnaw and break bones to various degrees in order to access marrow, grease, and brain tissue. In contrast, crocodiles attempt to swallow whole parts of mammal carcasses, inflicting in the process tooth marks and other feeding traces on some of the bones they are unable to ingest. Although crocodiles are major predators of larger mammals along the margins of protected tropical rivers and lakes, their feeding traces on bone have received little systematic attention in neotaphonomic research. We present diagnostic characteristics of Crocodylus niloticus damage to uningested mammal bones resulting from a series of controlled observations of captive crocodile feeding. The resulting bone assemblages are composed of primarily complete elements from articulating units, some of which bear an extremely high density of shallow to deep, transversely to obliquely oriented tooth scores over often large areas of the bone, along with shallow to deep pits and punctures. Some of the tooth marks (bisected pits and punctures, hook scores) have a distinctive morphology we have not observed to be produced by mammalian carnivores. The assemblages are also characterized by the retention of both low- and high-density bone portions, an absence of gross gnawing, and minimal fragmentation. Together, the damage characteristics associated with feeding by crocodiles are highly distinctive from those produced by mammalian carnivores. Modern surface bone assemblages along the Grumeti River in Tanzania's Serengeti National Park contain a mixture of specimens bearing damage characteristic of crocodiles and mammalian carnivores. Comparison of Plio-Pleistocene fossil bones from Olduvai Gorge, Tanzania, to bones damaged by captive and free-ranging Nile crocodiles reveals direct evidence of fossil crocodilian feeding from larger

  9. Regional warming and the thermal regimes of American crocodile nests in the Tempisque Basin, Costa Rica.

    PubMed

    Murray, Christopher M; Easter, Michael; Padilla, Sergio; Marin, Mahmood Sasa; Guyer, Craig

    2016-08-01

    Spatial variation in global climate change makes population-specific responses to this enigmatic threat pertinent on a regional scale. Organisms with temperature-dependent sex determination (TSD) potentially possess a unique physiological susceptibility that threatens population viability if rapid environmental effects on sex ratios render populations non-viable. A heavily male-biased sex ratio for hatchling American crocodiles of the Tempisque Basin, Costa Rica requires assessment of how nest temperature affects sex determination at this site, how females might compensate for these effects when creating nests, and how current patterns of climate change might alter future sex ratios and survival in hatchling cohorts. We demonstrate high within-nest variation in temperature but predict a female bias at hatching based on nest temperatures quantified here. Further, our data suggest that egg size and metabolic heating associated with this factor outweighs microhabitat parameters and depth in influencing nest thermal regimes. Finally, we document regional warming in the Tempisque Basin over the last 15 years and project that further heating over the next 15 years will not yield hatchling sex ratios as male biased as those currently found at this site. Thus, we find no support for nest temperature or climate change as likely explanations for male-biased American crocodile (Crocodylus acutus) sex ratios in the Tempisque Basin. PMID:27503716

  10. A third case of amelia in Morelet's crocodile from the Yucatan Peninsula.

    PubMed

    Charruau, Pierre; Niño-Torres, Carlos A

    2014-07-01

    Congenital defects in crocodilians have received little interest. In the context of global change and increasing threats to biodiversity, data on birth defects occurring in wildlife could be of importance for estimating the health of species populations and their ecosystems. Herein, we report the first case of amelia (i.e. absence of limbs) in Morelet's crocodiles Crocodylus moreletii from Mexico and the third on the southern Yucatan Peninsula. The crocodile in question was a juvenile (41 cm total length) captured in July 2012 in the Río Hondo, the river that forms the border between Mexico and Belize south of the state of Quintana Roo. The prevalence of this malformation in the C. moreletii population of Río Hondo (0.35%) is similar to that reported in 2 previous cases in Belize. Several causes of birth defects in crocodilians have previously been cited in the literature. Although we do not have relevant information to elucidate this case, we discuss some plausible explanations for this birth defect. PMID:24991853

  11. Saltwater and hard water bentonite mud

    SciTech Connect

    Pabley, A. S.

    1985-02-19

    A seawater/saltwater or hard water bentonite mud for use in drilling, and process for preparing same, comprising sequentially adding to seawater, to saltwater of a chloride concentration up to saturation, or hard water: a caustic agent; a filtration control agent; and bentonite. The resultant drilling mud meets API standards for viscosity and water loss, and is stable after aging and at tempertures in excess of 100/sup 0/ c. In another embodiment, the additives are premixed as dry ingredients and hydrated with seawater, saltwater or hard water. Unlike other bentonite drilling muds, the muds of this invention require no fresh water in their preparation, which makes them particularly useful at off-shore and remote on-shore drilling locations. The muds of this invention using bentonite further require less clay than known saltwater muds made with attapulgite, and provides superior filtration control, viscosity and stability.

  12. In Vitro and in Vivo Wound Healing Properties of Plasma and Serum from Crocodylus siamensis Blood.

    PubMed

    Jangpromma, Nisachon; Preecharram, Sutthidech; Srilert, Thanawan; Maijaroen, Surachai; Mahakunakorn, Pramote; Nualkaew, Natsajee; Daduang, Sakda; Klaynongsruang, Sompong

    2016-06-28

    The plasma and serum of Crocodylus siamensis have previously been reported to exhibit potent antimicrobial, antioxidant, and anti-inflammatory activities. During wound healing, these biological properties play a crucial role for supporting the formation of new tissue around the injured skin in the recovery process. Thus, this study aimed to evaluate the wound healing properties of C. siamensis plasma and serum. The collected data demonstrate that crocodile plasma and serum were able to activate in vitro proliferation and migration of HaCaT, a human keratinocyte cell line, which represents an essential phase in the wound healing process. With respect to investigating cell migration, a scratch wound experiment was performed which revealed the ability of plasma and serum to decrease the gap of wounds in a dose-dependent manner. Consistent with the in vitro results, remarkably enhanced wound repair was also observed in a mouse excisional skin wound model after treatment with plasma or serum. The effects of C. siamensis plasma and serum on wound healing were further elucidated by treating wound infections by Staphylococcus aureus ATCC 25923 on mice skin coupled with a histological method. The results indicate that crocodile plasma and serum promote the prevention of wound infection and boost the re-epithelialization necessary for the formation of new skin. Therefore, this work represents the first study to demonstrate the efficiency of C. siamensis plasma and serum with respect to their wound healing properties and strongly supports the utilization of C. siamensis plasma and serum as therapeutic products for injured skin treatment. PMID:26975771

  13. Crocodylus siamensis serum and macrophage phagocytic activity.

    PubMed

    Aree, Kalaya; Siruntawineti, Jindawan; Chaeychomsri, Win

    2011-12-01

    Antimicrobial activity of sera from many crocodilian species has been recognized. This activity was proposed to be mediated, at least in part, by complement. Due to the fact that complement proteins have different functions in the immune system, they may be involved in phagocytic process of phagocytes. In the present study, the effects of Siamese crocodile serum on phagocytic activity of macrophages as well as the possible involvement of complement in this process were examined. The results showed increases in the phagocytosis of both Escherichia coli and to a lesser extent, Staphylococcus aureus upon incubation of murine macrophage cell line with fresh crocodile serum (FS). Similar to FS, other crocodile blood products, including freeze dried serum (DS) and freeze dried whole blood (DWB) exhibited phagocytosis-enhancing property. However the ability of DWB to enhance phagocytosis was less efficient than that of FS and DS, suggesting that serum factors were involved in this process. Treatment of FS with heat at 56 degrees C for 30 min deteriorated the effect of FS on bacterial uptake of macrophages, suggesting that complement proteins play a role in the modulation of the phagocytic process. Collectively, the results of the present study suggested that crocodile serum enhances the macrophage phagocytic activity through complement activity and, therefore, may be taken as an alternative medicine for supporting the human immune responses. PMID:22619919

  14. [Genetic variability in captive populations of Crocodylus moreletii (Crocodylia: Crocodylidae) using microsatellites markers].

    PubMed

    Serna-Lagunes, Ricardo; González, Dolores; Díaz-Rivera, Pablo

    2012-03-01

    Crocodylus moreletii, an extinction threatened species, represents an emblem for tropical ecosystems in Mexico. Surprisingly, there is a lack of information about their genetic constitution, which should be evaluated for a proper management ex situ and for making decisions on the release of crocodiles into natural habitats. The aim of this study was to characterize and compare the genetic variability of four populations of C. moreletii (two wild versus two born ex situ). Through PCR were amplified seven microsatellite polymorphic loci, however a heterozygote deficit, diminished by the presence of null alleles, was found in the populations (average Ho=0.02). The AMOVA indicated that the highest proportion of genetic variability is within populations, and a limited genetic differentiation among populations (average F(ST)=0.03), probably due to high inbreeding index (average F(IS)=0.97). When comparing the genetic variability between and within other crocodilian species, we found that in C. moreletii is well below those reported. We concluded that the limited genetic variability in ex situ born populations is probably due to a founder effect derived from the social structure of their progenitors, and by the bottleneck effect, inferred by the limited effective population size, that historically characterizes their natural distribution in wild populations. PMID:22458236

  15. Oklahoma's recent earthquakes and saltwater disposal.

    PubMed

    Walsh, F Rall; Zoback, Mark D

    2015-06-01

    Over the past 5 years, parts of Oklahoma have experienced marked increases in the number of small- to moderate-sized earthquakes. In three study areas that encompass the vast majority of the recent seismicity, we show that the increases in seismicity follow 5- to 10-fold increases in the rates of saltwater disposal. Adjacent areas where there has been relatively little saltwater disposal have had comparatively few recent earthquakes. In the areas of seismic activity, the saltwater disposal principally comes from "produced" water, saline pore water that is coproduced with oil and then injected into deeper sedimentary formations. These formations appear to be in hydraulic communication with potentially active faults in crystalline basement, where nearly all the earthquakes are occurring. Although most of the recent earthquakes have posed little danger to the public, the possibility of triggering damaging earthquakes on potentially active basement faults cannot be discounted. PMID:26601200

  16. Spatial Ecology of the American Crocodile in a Tropical Pacific Island in Central America

    PubMed Central

    Balaguera-Reina, Sergio A.; Venegas-Anaya, Miryam; Sánchez, Andrés; Arbelaez, Italo; Lessios, Harilaos A.; Densmore, Llewellyn D.

    2016-01-01

    Conservation of large predators has long been a challenge for biologists due to the limited information we have about their ecology, generally low numbers in the wild, large home ranges and the continuous expansion of human settlements. The American crocodile (Crocodylus acutus) is a typical apex predator, that has suffered from all of these characteristic problems, especially the latter one. Humans have had a major impact on the recovery of this species throughout its range, even though most of the countries it inhabits have banned hunting. The last decade has made it clear that in order to implement sound conservation and management programs, we must increase our understanding of crocodile spatial ecology. However, in only two countries where American crocodiles have telemetry studies even been published. Herein we have characterized the spatial ecology of C. acutus on Coiba Island, Panama, by radio-tracking (VHF transmitters) 24 individuals between 2010 and 2013, to determine movement patterns, home range, and habitat use. We have then compared our findings with those of previous studies to develop the most comprehensive assessment of American crocodile spatial ecology to date. Females showed a higher average movement distance (AMD) than males; similarly, adults showed a higher AMD than sub-adults and juveniles. However, males exhibited larger home ranges than females, and concomitantly sub-adults had larger home ranges than juveniles, hatchlings, and adults. There was an obvious relationship between seasonal precipitation and AMD, with increased AMD in the dry and “low-wet” seasons, and reduced AMD during the “true” wet season. We found disaggregate distributions according to age groups throughout the 9 habitat types in the study area; adults and hatchlings inhabited fewer habitat types than juveniles and sub-adults. These sex- and age-group discrepancies in movement and habitat choice are likely due to the influences of reproductive biology and Coiba

  17. Spatial Ecology of the American Crocodile in a Tropical Pacific Island in Central America.

    PubMed

    Balaguera-Reina, Sergio A; Venegas-Anaya, Miryam; Sánchez, Andrés; Arbelaez, Italo; Lessios, Harilaos A; Densmore, Llewellyn D

    2016-01-01

    Conservation of large predators has long been a challenge for biologists due to the limited information we have about their ecology, generally low numbers in the wild, large home ranges and the continuous expansion of human settlements. The American crocodile (Crocodylus acutus) is a typical apex predator, that has suffered from all of these characteristic problems, especially the latter one. Humans have had a major impact on the recovery of this species throughout its range, even though most of the countries it inhabits have banned hunting. The last decade has made it clear that in order to implement sound conservation and management programs, we must increase our understanding of crocodile spatial ecology. However, in only two countries where American crocodiles have telemetry studies even been published. Herein we have characterized the spatial ecology of C. acutus on Coiba Island, Panama, by radio-tracking (VHF transmitters) 24 individuals between 2010 and 2013, to determine movement patterns, home range, and habitat use. We have then compared our findings with those of previous studies to develop the most comprehensive assessment of American crocodile spatial ecology to date. Females showed a higher average movement distance (AMD) than males; similarly, adults showed a higher AMD than sub-adults and juveniles. However, males exhibited larger home ranges than females, and concomitantly sub-adults had larger home ranges than juveniles, hatchlings, and adults. There was an obvious relationship between seasonal precipitation and AMD, with increased AMD in the dry and "low-wet" seasons, and reduced AMD during the "true" wet season. We found disaggregate distributions according to age groups throughout the 9 habitat types in the study area; adults and hatchlings inhabited fewer habitat types than juveniles and sub-adults. These sex- and age-group discrepancies in movement and habitat choice are likely due to the influences of reproductive biology and Coiba

  18. Acute toxicity of trichloroethylene to saltwater organisms

    SciTech Connect

    Ward, G.S.; Tolmsoff, A.J.; Petrocelli, S.R.

    1986-12-01

    Trichloroethylene (TCE) is a chlorinated aliphatic hydrocarbon primarily utilized for vapor-phase degreasing in the fabricated metals industry. Other applications include cold-metal cleaning and use in the manufacture of organic chemicals. TCE enters the environment as a result of volatilization during its production and through its industrial uses. TCE has been detected in aquatic environments and organisms at part-per-trillion (pptr) concentrations. Although TCE is indicated to be widely distributed, relatively limited data exist on the acute effects of TCE on aquatic organisms, especially saltwater species. Results of static acute tests of TCE with a saltwater alga, invertebrate, and fish are reported here to enhance the data base.

  19. Pulmonary anatomy in the Nile crocodile and the evolution of unidirectional airflow in Archosauria.

    PubMed

    Schachner, Emma R; Hutchinson, John R; Farmer, Cg

    2013-01-01

    The lungs of birds have long been known to move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi). Recently a similar pattern of airflow has been observed in American alligators, a sister taxon to birds. The pattern of flow appears to be due to the arrangement of the primary and secondary bronchi, which, via their branching angles, generate inspiratory and expiratory aerodynamic valves. Both the anatomical similarity of the avian and alligator lung and the similarity in the patterns of airflow raise the possibility that these features are plesiomorphic for Archosauria and therefore did not evolve in response to selection for flapping flight or an endothermic metabolism, as has been generally assumed. To further test the hypothesis that unidirectional airflow is ancestral for Archosauria, we measured airflow in the lungs of the Nile crocodile (Crocodylus niloticus). As in birds and alligators, air flows cranially to caudally in the cervical ventral bronchus, and caudally to cranially in the dorsobronchi in the lungs of Nile crocodiles. We also visualized the gross anatomy of the primary, secondary and tertiary pulmonary bronchi of C. niloticus using computed tomography (CT) and microCT. The cervical ventral bronchus, cranial dorsobronchi and cranial medial bronchi display similar characteristics to their proposed homologues in the alligator, while there is considerable variation in the tertiary and caudal group bronchi. Our data indicate that the aspects of the crocodilian bronchial tree that maintain the aerodynamic valves and thus generate unidirectional airflow, are ancestral for Archosauria. PMID:23638399

  20. Pulmonary anatomy in the Nile crocodile and the evolution of unidirectional airflow in Archosauria

    PubMed Central

    Hutchinson, John R.; Farmer, CG

    2013-01-01

    The lungs of birds have long been known to move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi). Recently a similar pattern of airflow has been observed in American alligators, a sister taxon to birds. The pattern of flow appears to be due to the arrangement of the primary and secondary bronchi, which, via their branching angles, generate inspiratory and expiratory aerodynamic valves. Both the anatomical similarity of the avian and alligator lung and the similarity in the patterns of airflow raise the possibility that these features are plesiomorphic for Archosauria and therefore did not evolve in response to selection for flapping flight or an endothermic metabolism, as has been generally assumed. To further test the hypothesis that unidirectional airflow is ancestral for Archosauria, we measured airflow in the lungs of the Nile crocodile (Crocodylus niloticus). As in birds and alligators, air flows cranially to caudally in the cervical ventral bronchus, and caudally to cranially in the dorsobronchi in the lungs of Nile crocodiles. We also visualized the gross anatomy of the primary, secondary and tertiary pulmonary bronchi of C. niloticus using computed tomography (CT) and microCT. The cervical ventral bronchus, cranial dorsobronchi and cranial medial bronchi display similar characteristics to their proposed homologues in the alligator, while there is considerable variation in the tertiary and caudal group bronchi. Our data indicate that the aspects of the crocodilian bronchial tree that maintain the aerodynamic valves and thus generate unidirectional airflow, are ancestral for Archosauria. PMID:23638399

  1. Thermal fluctuation within nests and predicted sex ratio of Morelet's Crocodile.

    PubMed

    Escobedo-Galván, Armando H; López-Luna, Marco A; Cupul-Magaña, Fabio G

    2016-05-01

    Understanding the interplay between thermal variations and sex ratio in reptiles with temperature-dependent sex determination is the first step for developing long-term conservation strategies. In case of crocodilians, the information is fragmentary and insufficient for establishing a general framework to consider how thermal fluctuation influence sex determination under natural conditions. The main goal of this study was to analyze thermal variation in nests of Crocodylus moreletii and to discuss the potential implications for predicting offspring sex ratio. The study was carried out at the Centro de Estudios Tecnológicos del Mar N° 2 and at the Sistemas Productivos Cocodrilo, Campeche, Mexico. Data was collected in the nesting season of Morelet's Crocodiles during three consecutive seasons (2007-2009). Thermal fluctuations for multiple areas of the nest chamber were registered by data loggers. We calculate the constant temperature equivalent based on thermal profiles among nests to assess whether there are differences between the nest temperature and its equivalent to constant temperature. We observed that mean nest temperature was only different among nests, while daily thermal fluctuations vary depending on the depth position within the nest chamber, years and nests. The constant temperature equivalent was different among and within nests, but not among survey years. We observed differences between constant temperature equivalent and mean nest temperature both at the top and in the middle of the nest cavities, but were not significantly different at the bottom of nest cavities. Our results enable examine and discuss the relevance of daily thermal fluctuations to predict sex ratio of the Morelet's Crocodile. PMID:27157330

  2. Saltwater injection systems can tolerate higher velocities

    SciTech Connect

    Salama, M.M. )

    1993-07-12

    The API erosional velocity limit is overly conservative for saltwater injection systems constructed from corrosion-resistant material and containing no solids in the water. Under such conditions and providing that pressure drop is not of concern, a flow velocity of 50 fps can be safely used without concern for erosion. The paper discusses the selection of flow velocity, the API criterion, velocity limits, and a calculation example.

  3. Fatigue crack retardation of low carbon steel in saltwater

    SciTech Connect

    Kokaji, K.; Ando, Z.; Kojima, T.

    1984-01-01

    The crack propagation behavior following the application of a single tensile overload in 3 percent saltwater was examined using a low carbon steel, which has a considerably lower static strength than high strength steel used in previous report. Experiments were carried out under sinusoidally varying loads at a load ratio of O and a frequency of 10 Hz, and the effects of saltwater were evaluated by comparing with the result in air and result on high strength steel. A single tensile overload was found to cause delayed retardation, just as it did in air. The overload affected zone size was not affected by saltwater and showed the same value in both environments. This observed trend differed from the result on high strength steel in which the overload affected zone size was larger in 3 percent saltwater than in air, and thus it was found that the effect of saltwater on retardation behavior was different even in the similar steels. Retardation cycles were smaller in 3 percent saltwater than in air. Since the overload affected zone size was not affected by saltwater, the decrease in retardation cycles was attributed to the higher rates of fatigue crack propagation in 3 percent saltwater. Thinner specimen showed stronger retardation than thicker one. The behavior at midthickness of thicker specimen showed delayed retardation as well as the result in air. Moreover, the crack propagation behavior following the application of a single tensile overload in 3 percent saltwater was well explained by the crack closure concept.

  4. Integration of autonomic and local mechanisms in regulating cardiovascular responses to heating and cooling in a reptile (Crocodylus porosus).

    PubMed

    Seebacher, Frank; Franklin, Craig E

    2004-10-01

    Reptiles change heart rate and blood flow patterns in response to heating and cooling, thereby decreasing the behavioural cost of thermoregulation. We tested the hypothesis that locally produced vasoactive substances, nitric oxide and prostaglandins, mediate the cardiovascular response of reptiles to heat. Heart rate and blood pressure were measured in eight crocodiles (Crocodylus porosus) during heating and cooling and while sequentially inhibiting nitric-oxide synthase and cyclooxygenase enzymes. Heart rate and blood pressure were significantly higher during heating than during cooling in all treatments. Power spectral density of heart rate and blood pressure increased significantly during heating and cooling compared to the preceding period of thermal equilibrium. Spectral density of heart rate in the high frequency band (0.19-0.70 Hz) was significantly greater during cooling in the saline treatment compared to when nitric-oxide synthase and cyclooxygenase enzymes were inhibited. Cross spectral analysis showed that changes in blood pressure preceded heart rate changes at low frequencies (< 0.1 Hz) only. We conclude that the autonomic nervous system controls heart rate independently from blood pressure at higher frequencies while blood pressure changes determine heart rate at lower frequencies. Nitric oxide and prostaglandins do not control the characteristic heart rate hysteresis response to heat in C. porosus, although nitric oxide was important in buffering blood pressure against changes in heart rate during cooling, and inhibition caused a compensatory decrease in parasympathetic stimulation of the heart. PMID:15340754

  5. 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)

  6. Thermohaline stability of horizontal layers of saltwater

    SciTech Connect

    Shamsundar, N.; Krishna, C.N.

    1999-07-01

    The thermohaline stability of horizontal layers of saltwater (with cold fresh water on top of warm salty water) was studied using analytical and numerical methods. The marginal oscillatory instability state was calculated for different boundary conditions for uniform s well as for nonuniform temperature and salinity gradients. A correlation was developed to use the ratio of the mean gradient to the maximum gradient to enable stability results for nonlinear gradients to be extrapolated from simpler results for linear gradients. Contrary to published expectations, localized stability criteria are not suitable for calculating the effects of nonlinear temperature gradients.

  7. Monitoring Coastal Marshes for Persistent Saltwater Intrusion

    NASA Technical Reports Server (NTRS)

    Kalcic, Maria; Hall, Callie; Fletcher, Rose; Russell, Jeff

    2009-01-01

    Primary goal: Provide resource managers with remote sensing products that support ecosystem forecasting models requiring salinity and inundation data. Work supports the habitat-switching modules in the Coastal Louisiana Ecosystem Assessment and Restoration (CLEAR) model, which provides scientific evaluation for restoration management (Visser et al., 2008). Ongoing work to validate flooding with radar (NWRC/USGS) and enhance persistence estimates through "fusion" of MODIS and Landsat time series (ROSES A.28 Gulf of Mexico). Additional work will also investigate relationship between saltwater dielectric constant and radar returns (Radarsat) (ROSES A.28 Gulf of Mexico).

  8. How to Add Life to a Saltwater Aquarium.

    ERIC Educational Resources Information Center

    Charlton, Anthony

    1991-01-01

    Describes how to set up an economical saltwater aquarium and where to obtain supplies and inhabitants. Discusses the characteristics of a saltwater aquarium, proper aquarium maintenance, the compatibility of diverse life forms, and the time scale necessary to develop and sustain a favorable natural environment. (nine references) (Author/JJK)

  9. Saltwater Anopheles gambiae” on Mauritius*

    PubMed Central

    Paterson, H. E.

    1964-01-01

    In this paper the author reports the results of three months' study of the saltwater-breeding member of the Anopheles gambiae complex of sibling species on Mauritius. There is evidence for the views that this form's distribution on the island is limited by the availability of suitable breeding areas, that it does not usually disperse far from the breeding grounds or coast, and that it is probably not an important vector except, perhaps, in the near vicinity of its breeding places. Some new evidence is presented in support of the view that this form (and forms A and B) are distinct species. This turns on the observed close coexistence of these three forms on Mauritius, supported by a theoretical consideration of what would be expected to happen in such circumstances if a system of random mating prevailed. Evidence is given that the Mauritian saltwater-breeding form of the A. gambiae complex is conspecific with the form occurring on the east coast of Africa. The practical importance of reaching general agreement on the evolutionary status of the members of the A. gambiae complex is emphasized. PMID:14278002

  10. Paraoistosomum novaeguineae n. gen., n. sp. (Digenea) from a New Guinea crocodile: a surprising relative of the enigmatic Oistosomum caduceus Odhner, 1902.

    PubMed

    Tkach, Vasyl V

    2011-08-01

    Paraoistosomum novaeguineae n. gen., n. sp. is described based on specimens from the kidneys of a New Guinea crocodile Crocodylus novaeguineae collected in Papua New Guinea. The body shape and the topology of most internal organs of the new species are strongly reminiscent of Oistosomum caduceus Odhner 1902, the sole member of Oistosomum, a genus of unclear phylogenetic relationships and systematic position described from the Nile crocodile in Sudan in 1902 and never reported since then. At the same time, the new species has a number of significant differences from Oistosomum caduceus. Among them are much shorter intestinal ceca, a relatively larger ventral sucker, ovary anterolateral to ventral sucker (posterolateral in O. caduceus ), vitellaria arranged in 2 clusters of loosely organized follicles at the level of ventral sucker (2 narrow long lateral fields in O. caduceus ), much longer esophagus, and other characters. Most importantly, the new species has the genital pore situated at the anterior body end adjacent to the oral sucker, whereas O. caduceus has the genital pore in front of the ventral sucker. These dramatic differences suggest establishment of a new genus for the species from Papua New Guinea. The anatomy of P. novaeguineae n. gen., n. sp. suggests that these genera may not belong to the Plagiorchiidae, the current familial allocation of Oistosomum. Scarcity of material and lack of molecular data do not permit clarification of this problem at the present time. PMID:21506816

  11. Analysis of saltwater upconing beneath a pumping well

    USGS Publications Warehouse

    Reilly, T.E.; Goodman, A.S.

    1987-01-01

    Aquifer systems that contain freshwater and saltwater are usually stratified, with the more dense saltwater underlying the freshwater. A groundwater well discharging from the freshwater zone causes the saltwater to move upwards towards the well. This phenomenon is known as saltwater upconing. Two methods of analysis, the sharp-interface method and the fluid-density-dependent solute-transport method, are used to simulate saltwater upconing. Numerical experiments including comparisons of the two methods indicate: (1) for low to moderate pumpages the 50% isochlor and sharp interface correlate well; (2) the well can discharge significant concentrations of saltwater, even though a stable cone (according to the sharp-interface method) exists below the well screen; (3) an almost linear relationship exists between the well discharge rate and the concentration of the discharge at low pumping rates that maintain a stable cone; and (4) upconing is sensitive to transverse dispersivity, whereas it is insensitive to longitudinal dispersivity. A simulation of upconing at Test Site No. 4, Truro, Cape Cod, Massachusetts, indicates that the appropriate field value of transverse dispersivity is very small. This supports the validity of the sharp-interface assumption for analyzing the behavior of systems with thin saltwater-freshwater transition zones. ?? 1987.

  12. Saltwater intrusion in coastal regions of North America

    NASA Astrophysics Data System (ADS)

    Barlow, Paul M.; Reichard, Eric G.

    2010-02-01

    Saltwater has intruded into many of the coastal aquifers of the United States, Mexico, and Canada, but the extent of saltwater intrusion varies widely among localities and hydrogeologic settings. In many instances, the area contaminated by saltwater is limited to small parts of an aquifer and to specific wells and has had little or no effect on overall groundwater supplies; in other instances, saltwater contamination is of regional extent and has resulted in the closure of many groundwater supply wells. The variability of hydrogeologic settings, three-dimensional distribution of saline water, and history of groundwater withdrawals and freshwater drainage has resulted in a variety of modes of saltwater intrusion into coastal aquifers. These include lateral intrusion from the ocean; upward intrusion from deeper, more saline zones of a groundwater system; and downward intrusion from coastal waters. Saltwater contamination also has occurred along open boreholes and within abandoned, improperly constructed, or corroded wells that provide pathways for vertical migration across interconnected aquifers. Communities within the coastal regions of North America are taking actions to manage and prevent saltwater intrusion to ensure a sustainable source of groundwater for the future. These actions can be grouped broadly into scientific monitoring and assessment, engineering techniques, and regulatory approaches.

  13. Heterochronic shift between early organogenesis and migration of cephalic neural crest cells in two divergent evolutionary phenotypes of archosaurs: crocodile and ostrich.

    PubMed

    Kundrát, Martin

    2009-01-01

    Living archosaurs (crocodiles and birds) represent an intriguing evo-devo model system. Although close in phylogenetic relationship, the two lineages show considerable divergence in trends of phenotypic evolution. The head anatomy of recent crocodilians has changed little in comparison with that of their crocodylomorph ancestors. The head phenotype of the avians (birds), as well as some non-avian theropods, shows numerous evolutionary innovations that differ considerably from the crocodylomorph pattern. Most of the novel head structures, such as features of the craniofacial skeleton, cranial nerves, head muscles, and integument are derived from the same cellular source common to all archosaurs, the cephalic neural crest (CNC). Therefore, other factors must be involved in the developmental disparity of homologous structures in the aforementioned lineages. The present study analyzes the earliest developmental events that are associated with the appearance of the neural crest cells in the two archosaur models: Crocodylus niloticus and Struthio camelus. I found that both models share unique developmental features, the presence of an unpaired, rostrally migrating population of CNC cells, showing that the two are closely related to each other. On the other hand, the crocodile and the ostrich differ substantially in (1) timing, (2) duration, and (3) expression patterns of the CNC. Compared with the crocodile, the CNC cells in the ostrich (1) migrate much later into the embryonic head, (2) but relocate to their terminal positions faster, and (3) take specifically directed migratory routes in the mandibular/oral region and head/trunk-interface regions. I suggest that accelerated relocation of CNC cells combined with delayed head organogenesis may represent important innovative conditions in the developmental evolution of a new archosaur head phenotype. PMID:19754710

  14. Laboratory Experiment of Saltwater Intrusion into Freshwater Aquifer

    NASA Astrophysics Data System (ADS)

    Maekawa, K.; Karasaki, K.; Takasu, T.

    2006-12-01

    It is important for safety assessment of high-level radioactive waste geologic disposal to understand groundwater flow in deep underground accurately. Especially groundwater flow in the coastal area considered to be quite complex that involves density and hydraulic gradient driven flow of freshwater and saltwater. Furthermore, bentonite, which is one of the favored artificial barrier materials, may not swell very well in saltwater as it does in freshwater, and therefore may not provide a reliable seal if salinity is high enough. In order to understand the behavior of saltwater intrusion into freshwater in deep underground, we constructed a laboratory equipment "Mini-MACRO" named after the original large scale MACRO (MAss transport Characterization in host ROck) and aimed to increase a precision and efficiency of experiment. Mini-MACRO equipment consists of three parts: a sandbox (0.5m x 0.25m x 0.1m) and each reservoir tank for saltwater and freshwater. Saltwater intrusion experiments are conducted using glass beads (sub-millimeter in diameter) and colored saltwater in the sandbox with a transparent face plate to allow visual observation. In the present paper we summarize the concept of the equipment design and the results of the experiment that we created several cases of experimental conditions to observe the saltwater intrusion behavior against various hydraulic gradients and densities of saltwater. This equipment contributes to the better understanding of saltwater intrusion behavior and to increasing confidence in modeling methodology of groundwater flow and mass transport in deep underground through comparison with numerical analysis. We believe that it is crucial for the safety assessment of geologic disposal to integrate this knowledge.

  15. Coastal Marsh Monitoring for Persistent Saltwater Intrusion

    NASA Technical Reports Server (NTRS)

    Hall, Callie M.

    2008-01-01

    This viewgraph presentation reviews NASA's work on the project that supports the Gulf of Mexico Alliance (GOMA) Governors Action Plan to monitor the coastal wetlands for saltwater intrusion. The action items that relate to the task are: (1) Obtain information on projected relative sea level rise, subsidence, and storm vulnerability to help prioritize conservation projects, including restoration, enhancement, and acquisition, and (2) Develop and apply ecosystem models to forecast the habitat structure and succession following hurricane disturbance and changes in ecological functions and services that impact vital socio-economic aspects of coastal systems. The objectives of the program are to provide resource managers with remote sensing products that support ecosystem forecasting models requiring salinity and inundation data. Specifically, the proposed work supports the habitat-switching modules in the Coastal Louisiana Ecosystem Assessment and Restoration (CLEAR) model, which provides scientific evaluation for restoration management.

  16. Crocodilian phylogeny inferred from twelve mitochondrial protein-coding genes, with new complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae.

    PubMed

    Man, Zhang; Yishu, Wang; Peng, Yan; Xiaobing, Wu

    2011-07-01

    We report complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae, whose gene orders match those of other crocodilians. Phylogenetic analyses based on the sequences of 12 mitochondrial protein-coding genes support monophyly of two crocodilian taxonomic families, Alligatoridae (genera Alligator, Caiman, and Paleosuchus) and Crocodylidae (genera Crocodylus, Gavialis, Mecistops, Osteolaemus, and Tomistoma). Our results are consistent with monophyly of all crocodilian genera. Within Alligatoridae, genus Alligator is the sister taxon of a clade comprising Caiman and Paleosuchus. Within Crocodylidae, the basal phylogenetic split separates a clade comprising Gavialis and Tomistoma from a clade comprising Crocodylus, Mecistops, and Osteolaemus. Mecistops and Osteolaemus form the sister taxon to Crocodylus. Within Crocodylus, we sampled five Indopacific species, whose phylogenetic ordering is ((C. mindorensis, C. novaeguineae), (C. porosus, (C. siamensis, C. palustris))). The African species C. niloticus and New World species C. acutus form the sister taxon to the Indopacific species, although our sampling lacks three other New World species and an Australian species of Crocodylus. PMID:21463698

  17. A saltwater flotation technique to identify unincubated eggs

    USGS Publications Warehouse

    Devney, C.A.; Kondrad, S.L.; Stebbins, K.R.; Brittingham, K.D.; Hoffman, D.J.; Heinz, G.H.

    2009-01-01

    Field studies on nesting birds sometimes involve questions related to nest initiation dates, length of the incubation period, or changes in parental incubation behavior during various stages of incubation. Some of this information can be best assessed when a nest is discovered before the eggs have undergone any incubation, and this has traditionally been assessed by floating eggs in freshwater. However, because the freshwater method is not particularly accurate in identifying unincubated eggs, we developed a more reliable saltwater flotation method. The saltwater method involves diluting a saturated saltwater solution with freshwater until a salt concentration is reached where unincubated eggs sink to the bottom and incubated eggs float to the surface. For Laughing Gulls (Leucophaeus atricilla), floating eggs in freshwater failed to identify 39.0% (N = 251) of eggs that were subsequently found by candling to have undergone incubation prior to collection. By contrast, in a separate collection of gull eggs, no eggs that passed the saltwater test (N = 225) were found by a later candling to have been incubated prior to collection. For Double-crested Cormorants (Phalacrocorax auritus), floating eggs in freshwater failed to identify 15.6% (N = 250) of eggs that had undergone incubation prior to collection, whereas in a separate collection, none of the eggs that passed the saltwater test (N = 85) were found by a later candling to have been incubated prior to collection. Immersion of eggs in saltwater did not affect embryo survival. Although use of the saltwater method is likely limited to colonial species and requires calibrating a saltwater solution, it is a faster and more accurate method of identifying unincubated eggs than the traditional method of floating eggs in freshwater.

  18. Complete mitochondrial genome sequences of three Crocodylus species and their comparison within the Order Crocodylia.

    PubMed

    Meganathan, P R; Dubey, Bhawna; Batzer, Mark A; Ray, David A; Haque, Ikramul

    2011-06-01

    Crocodylus is the largest genus within the Order Crocodylia consisting of eleven species. This paper reports the complete mitochondrial genome sequences of three Crocodylus species, Crocodylus moreletii, Crocodylus johnstoni and Crocodylus palustris, and compares the newly obtained mitochondrial DNA sequences with other crocodilians, available in the public databases. The mitochondrial genomes of C. moreletii, C. johnstoni and C. palustris are 16,827 bp, 16,851 bp and 16,852 bp in length, respectively. These mitochondrial genomes consist of 13 protein coding genes, two ribosomal RNA genes, 22 transfer RNA genes and a non-coding region. The mitochondrial genomes of all the Crocodylus species, studied herein show identical characteristics in terms of nucleotide composition and codon usage, suggestive of the existence of analogous evolutionary patterns within the genus, Crocodylus. The synonymous and non-synonymous substitution rates for all the protein coding genes of Crocodylus were observed in between 0.001 and 0.275 which reveal the prevalence of purifying selection in these genes. The phylogenetic analyses based on complete mitochondrial DNA data substantiate the previously established crocodilian phylogeny. This study provides a better understanding of the crocodilian mitochondrial genome and the data described herein will prove useful for future studies concerning crocodilian mitochondrial genome evolution. PMID:21310220

  19. Transmission studies on Trichinella species isolated from Crocodylus niloticus and efficacy of fenbendazole and levamisole against muscle L1 stages in Balb C mice.

    PubMed

    Mukaratirwa, S; Magwedere, K; Matenga, E; Foggin, C M

    2001-03-01

    Forty-four Balb C mice, aged 18 weeks were infected with crocodile (Crocodylus niloticus)-derived Trichinella species. Of the infected mice, 32 were randomly divided into two groups each containing equal numbers of males and females; levamisole treated group and fenbendazole treated group. Each group was randomly subdivided into two subgroups as follows: levamisole group (subgroup 1: treated with levamisole on day 35 post infection, and subgroup 2: treated with levamisole on days 35 and 42 post infection) and fenbendazole group (subgroup 1: treated with fenbendazole on day 35 post infection and subgroup 2: treated with fenbendazole on days 35 and 42 post infection). The first subgroups treated on day 35 post infection were slaughtered on day 42 post infection and the second subgroups were treated on day 35 and day 42 post infection and slaughtered on day 49 post infection. Two female mice were infected a day after mating and were slaughtered together with the offspring on day 64 post-infection. Ten infected control mice were given 1 ml distilled water orally as placebo, and five of these were slaughtered on day 42 post infection. The results showed that the mean reproductive capacity index of this strain (RCI) in Balb C mice was 110. There was a significant reduction (P < 0.01) in larval counts in the single treatment groups (day 35) and in the double treatment groups (days 35 and 42) for both anthelmintics when compared the number of parasites in the control groups. After a single treatment, levamisole reduced the infection by 79.9% and fenbendazole by 76.7%. Following double treatments, levamisole reduced the infection by 95.5% and fenbendazole by 99.1%. There was evidence that the infected pregnant mice transmitted the parasite to their offspring. It is not certain whether the parasite was transmitted congenitally or transmammary Alternative ways of controlling the parasite in crocodile farms in Zimbabwe are discussed. PMID:11403426

  20. Should I stay or should I go? Dispersal and population structure in small, isolated desert populations of West African crocodiles.

    PubMed

    Velo-Antón, Guillermo; Godinho, Raquel; Campos, João Carlos; Brito, José Carlos

    2014-01-01

    The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (FST range: 0.12-0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments. PMID:24740183

  1. Should I Stay or Should I Go? Dispersal and Population Structure in Small, Isolated Desert Populations of West African Crocodiles

    PubMed Central

    Campos, João Carlos; Brito, José Carlos

    2014-01-01

    The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (FST range: 0.12–0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments. PMID:24740183

  2. Crocodile bites and traditional beliefs in Korogwe District, Tanzania.

    PubMed Central

    Scott, R.; Scott, H.

    1994-01-01

    OBJECTIVES--To investigate why fatal crocodile bites are increasing in a Tanzanian district and the importance of traditional beliefs and superstitions in determining the residents' response to the crocodiles. DESIGN--Information about beliefs was obtained by interview of Korogwe residents. Human and crocodile fatality statistics were obtained from the Korogwe Department of Natural Resources. SETTING--Villages within Korogwe District. SUBJECTS--Population of Korogwe District. RESULTS--Crocodiles have been responsible for 51 deaths in the 52 months from January 1990 to April 1994. Of these, 18 deaths occurred in the first four months of 1994. CONCLUSIONS--Local beliefs and superstitions about crocodiles include those about the taming of animals, with implications concerning the choice of victim and the penalties that may ensue if a crocodile is killed. The recent rise in human fatalities is thought to relate to increasing river pollution reducing the fish supply, together with a change in social mores at the riverside which has increased the crocodiles' displeasure. A reliable pumped water supply would reduce the need to draw water and bathe in the river, and eradication of superstition would empower the villagers in the fight against a common enemy. Images p1692-a PMID:7819989

  3. Cationic Antimicrobial Peptides Derived from Crocodylus siamensis Leukocyte Extract, Revealing Anticancer Activity and Apoptotic Induction on Human Cervical Cancer Cells.

    PubMed

    Theansungnoen, Tinnakorn; Maijaroen, Surachai; Jangpromma, Nisachon; Yaraksa, Nualyai; Daduang, Sakda; Temsiripong, Theeranan; Daduang, Jureerut; Klaynongsruang, Sompong

    2016-06-01

    Known antimicrobial peptides KT2 and RT2 as well as the novel RP9 derived from the leukocyte extract of the freshwater crocodile (Crocodylus siamensis) were used to evaluate the ability in killing human cervical cancer cells. RP9 in the extract was purified by a combination of anion exchange column and reversed-phase HPLC, and its sequence was analyzed by mass spectrometry. The novel peptide could inhibit Gram-negative Vibrio cholerae (clinical isolation) and Gram-positive Bacillus pumilus TISTR 905, and its MIC values were 61.2 µM. From scanning electron microscopy, the peptide was seen to affect bacterial surfaces directly. KT2 and RT2, which are designed antimicrobial peptides using the C. siamensis Leucrocin I template, as well as RP9 were chemically synthesized for investigation of anticancer activity. By Sulforhodamine B colorimetric assay, these antimicrobial peptides could inhibit both HeLa and CaSki cancer cell lines. The IC50 values of KT2 and RT2 for HeLa and CaSki cells showed 28.7-53.4 and 17.3-30.8 µM, while those of RP9 were 126.2 and 168.3 µM, respectively. Additionally, the best candidate peptides KT2 and RT2 were used to determine the apoptotic induction on cancer cells by human apoptosis array assay. As a result, KT2 and RT2 were observed to induce apoptotic cell death in HeLa cells. Therefore, these results indicate that KT2 and RT2 with antimicrobial activity have a highly potent ability to kill human cervical cancer cells. PMID:27129462

  4. Conservation and management of the American crocodile

    NASA Astrophysics Data System (ADS)

    Kushlan, James A.

    1988-11-01

    The American crocodile is a rare and endangered species, the range of which has contracted to disjunct locations such as Hispaniola, Jamaica, Cuba, Panama, and southern Florida. In an attempt to determine what factors might be limiting population growth, an extensive collaborative research program was conducted in 1978 82 in southern Florida. Limiting factors explicitly studied included climate, hurricanes, population dispersion, nesting habitat, fertility, predation, nest chamber environment, juvenile survivorship, artificial mortality, disturbance, and environmental contamination. No single natural factor limits the population, although in concert various factors result in low adult recruitment rates. Such natural limitations explain the natural rarity of this tropical species at the temperate limits of its range. Two artificial sources of mortality are death of adults on roads and the flooding of nests by high groundwater tables. These sources of mortality are potentially controllable by the appropriate management agencies. Active management, by such means as protection of individuals, habitat preservation and enhancement, nest site protection, and captive breeding, is also appropriate for assuring the survival of a rare species. The American crocodile has survived in southern Florida in face of extensive human occupancy of parts of its former nesting habitat, demonstrating the resilience of a threatened species. This case history illustrates the efficacy of conducting research aimed at testing specific management hypotheses, the importance of considering biographical constraints limiting population status in peripheral populations, the need for active management of rare species, and the role of multiple reserves in a conservation and management strategy.

  5. The effect of beach slope on tidal influenced saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; Shen, C.; Jin, G.; Xin, P.; Hua, G.; Tao, X.; Zhao, J.

    2015-12-01

    Beach slope changes the tidal induced saltwater-freshwater circulations in coastal aquifers. However, the effect of beach slope on tidal influenced saltwater-freshwater mixing process is far from understood. Based on sand flume experiments and numerical simulations, we investigated the intrusion process of saltwater into freshwater under tidal forcing and variable beach slopes. The sand flume experiment results show that milder slope induces larger upper saline plume (USP) and seaward salt wedge interface (SWI) under tidal forcing. While, the steady state SWI keeps stagnant with different beach slopes. Consistent with the previous research, our numerical simulations also show a lager flux exchange across the milder beach induced by the tidal fluctuations. The groundwater table fluctuates more intensify with deeper beach slope. The next step of our study will pay attention to the effect of beach slope on the instability of USP which induces the salt-fingering flow.

  6. Oklahoma’s recent earthquakes and saltwater disposal

    PubMed Central

    Walsh, F. Rall; Zoback, Mark D.

    2015-01-01

    Over the past 5 years, parts of Oklahoma have experienced marked increases in the number of small- to moderate-sized earthquakes. In three study areas that encompass the vast majority of the recent seismicity, we show that the increases in seismicity follow 5- to 10-fold increases in the rates of saltwater disposal. Adjacent areas where there has been relatively little saltwater disposal have had comparatively few recent earthquakes. In the areas of seismic activity, the saltwater disposal principally comes from “produced” water, saline pore water that is coproduced with oil and then injected into deeper sedimentary formations. These formations appear to be in hydraulic communication with potentially active faults in crystalline basement, where nearly all the earthquakes are occurring. Although most of the recent earthquakes have posed little danger to the public, the possibility of triggering damaging earthquakes on potentially active basement faults cannot be discounted. PMID:26601200

  7. Surveys of tidal river systems in the northern territory of Australia and their crocodile populations

    SciTech Connect

    Vorlicek, G.C.; Messel, H.; Green, W.J.

    1986-01-01

    This book provides an update on the population dynamics of Crocodylus porous in the tidal waterways of Van Diemen Gulf and the Southern Gulf of Carpentaria, Australia, during 1984 and 1985. Contents: Prologue; Dedication; Introduction; Status of Crocodylus porous. July 1984, in the tidal waterways of the Alligator Region and in the Adelaide River System of Northern Australia: recovery underway; Resurvey of Crocodylus porous populations in the tidal waterways of the southern Gulf of Carpentaria, September - October 1985; Local knowledge - Northern Australia style.

  8. Saltwater Sources for Saltwater Intrusion in Shallow Aquifers in South Louisiana

    NASA Astrophysics Data System (ADS)

    Stoessell, R. K.; Prochaska, L.

    2005-05-01

    Shallow southward-dipping Quaternary and Upper Neogene aquifers across South Louisiana are used as sources of freshwater. Local accumulations of brackish waters occur within these aquifers on the north shore of Lake Pontchartrain, in the Baton Rouge area, in Southwest and South-central Louisiana, and in the New Orleans area. The low Br/Cl ratios, high Na/Cl ratios, low K/Cl ratios and low 87Sr/86Sr ratios in these brackish waters form linear mixing trends which are inconsistent with the saline-water sources being in situ marine formation fluids of similar age. Extrapolation of these ratios to fluids of high salinity suggests the saline-water sources are Lower Neogene or Paleogene marine formation fluids that dissolved halite. South Louisiana overlies the deep Jurassic Louan salt, which is the source of salt diapirs. The region is cut by a series of east-west trending gravity faults with southward-dipping fault planes. Deeper migrating formation fluids are hypothesized to be dissolving halite through contact with salt diapirs and moving up fault planes to enter shallow aquifers and mix with the in situ groundwaters. High freshwater withdrawal rates are accelerating this process, causing updip movement of the shallow saltwater fronts, e.g., within the Pliocene and Upper Miocene Baton Rouge aquifers and in the Pleistocene Lake Charles "500-foot" sand. Conversely, the absence of significant freshwater withdrawal has apparently caused a static saltwater front, e.g., in the Pliocene Big Branch Aquifer on the north shore of Lake Pontchartrain.

  9. Secondary anterior crocodile shagreen of Vogt.

    PubMed Central

    Tripathi, R C; Bron, A J

    1975-01-01

    The clincopathological features and pathogenesis of secondary mosaic degeneration of the cornea (anterior crocodile shagreen of Vogt) are described. The structural basis for the normal anterior corneal mosaic pattern seems to lie in the particular arrangement of many prominent collagen lamellae of the anterior stroma that thake an oblique course to gain insertion into Bowman's layer. Since, at normal intraocular pressure, Bowman's layer is under tension, when viewed from the anterior surface the cornea appears smooth. By releasing the tension, however, a reproducible polygonal ridge pattern becomes manifest. It is suggested that a prolonged phthisical state of the eye is one condition wherein the mosaic pattern may become permanent and that, as a secondary event, this is followed by irregular calcification of Bowman's layer which particularly involves the ridges projecting into the epithelium. Biomicroscopically these ridges corresponded to the branching reticular arrangement of the mosaic opacities. Images PMID:1079137

  10. Assessment of saltwater intrusion in southern coastal Broward County, Florida

    USGS Publications Warehouse

    Merritt, M.L.

    1996-01-01

    Of the counties in southeastern Florida, Broward County has experienced some of the most severe effects of saltwater intrusion into the surficial Biscayne aquifer because, before 1950, most public water-supply well fields in the county were constructed near the principal early population centers located less than 5 miles from the Atlantic Ocean. The construction of major regional drainage canals in the early 20th century caused a lowering of the water table and a gradual inland movement of the saltwater front toward the well fields. The U.S. Geological Survey began field investigations of saltwater intrusion in the Biscayne aquifer of southeastern Broward County in 1939. As part of the present study, the positions of the saltwater front in 1945, 1969, and 1993 were estimated using chloride concentrations of water samples collected between 1939 and 1994 from various monitoring and exploratory wells. The data indicate that, between 1945 and 1993, the saltwater front has moved as much as 0.5 mile inland in parts of the study area. The position and movement of the saltwater front were simulated numerically to help determine which of the various hydrologic factors and water-management features characterizing the coastal subsurface environment and its alteration by man are of significance in increasing or decreasing the degree of saltwater intrusion. Two representational methods were applied by the selection and use of appropriate model codes. The SHARP code simulates the position of the saltwater front as a sharp interface, which implies that no transition zone (a zone in which a gradational change between freshwater and saltwater occurs) separates freshwater and saltwater. The Subsurface Waste Injection Program (SWIP) code simulates a two-fluid, variable-density system using a convective-diffusion approach that includes a representation of the transition zone that occurs between the freshwater and saltwater bodies. The models were applied to: (1) approximately

  11. ACUTE TOXICITY OF PARA-NONYLPHENOL TO SALTWATER ANIMALS

    EPA Science Inventory

    ?para-Nonylphenol (PNP), a mixture of alkylphenols used in producing nonionic surfactants, is distributed widely in surface waters and aquatic sediments, where it can affect saltwater species. This article describes a database for acute toxicity of PNP derived for calculating a n...

  12. Fatigue crack retardation of high strength steel in saltwater

    SciTech Connect

    Tokaji, K.; Ando, Z.; Imai, T.; Kojima, T.

    1983-04-01

    A high strength steel was studied in 3 percent saltwater to investigate the effects of a corrosive environment and sheer thickness on fatigue crack propagation behavior following the application of a single tensile overload. Experiments were carried out under sinusoidally varying loads at a load ratio of 0 and frequency of 10 H /SUB z/ . A single tensile overload was found to cause delayed retardation, and the crack propagation rate at first increased, followed by fairly rapid decrease to a minimum value and then increased gradually to its steady-state value, just as it did in air. The overload affected zone size and the retardation cycles increased with decreasing sheet thickness, just as they did in air. However, the zone size and the cycles were larger in 3 percent saltwater than in air. Since the crack propagation rates through the overload affected zone were not affected by the test environment, the longer retardation cycles in 3 percent saltwater were attributed to an enlargement of the overload affected zone size. The crack propagation behavior following the application of a single tensile overload in 3 percent saltwater was well explained by the crack closure concept.

  13. Analysis of polarization decay of reinforced concrete in saltwater

    SciTech Connect

    Kumar, A.; Boy, J.H.

    1996-11-01

    Electrochemical impedance spectroscopy (EIS), polarization resistance, and polarization decay measurements techniques were used to analyze uncoated steel reinforcing rods encased in concrete and exposed to saltwater. A nested equivalent circuit containing a Warburg impedance was utilized to analyze the results. When rust is present on the steel, the Warburg impedance dominated the impedance response.

  14. 76 FR 57757 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ...-47878A The applicant requests a permit to import biological specimens of African dwarf crocodiles (Osteolaemus tetraspis tetraspis) and slender snouted crocodiles (Crocodylus cataphractus) collected from...

  15. Mechanics of fragmentation of crocodile skin and other thin films

    NASA Astrophysics Data System (ADS)

    Qin, Zhao; Pugno, Nicola M.; Buehler, Markus J.

    2014-05-01

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin.

  16. Home range utilisation and long-range movement of estuarine crocodiles during the breeding and nesting season.

    PubMed

    Campbell, Hamish A; Dwyer, Ross G; Irwin, Terri R; Franklin, Craig E

    2013-01-01

    The estuarine crocodile (Crocodylus porosus) is the apex-predator in waterways and coastlines throughout south-east Asia and Australasia. C. porosus pose a potential risk to humans, and management strategies are implemented to control their movement and distribution. Here we used GPS-based telemetry to accurately record geographical location of adult C. porosus during the breeding and nesting season. The purpose of the study was to assess how C. porosus movement and distribution may be influenced by localised social conditions. During breeding, the females (2.92 ± 0.013 metres total length (TL), mean ± S.E., n = 4) occupied an area<1 km length of river, but to nest they travelled up to 54 km away from the breeding area. All tagged male C. porosus sustained high rates of movement (6.49 ± 0.9 km d(-1); n = 8) during the breeding and nesting period. The orientation of the daily movements differed between individuals revealing two discontinuous behavioural strategies. Five tagged male C. porosus (4.17 ± 0.14 m TL) exhibited a 'site-fidelic' strategy and moved within well-defined zones around the female home range areas. In contrast, three males (3.81 ± 0.08 m TL) exhibited 'nomadic' behaviour where they travelled continually throughout hundreds of kilometres of waterway. We argue that the 'site-fidelic' males patrolled territories around the female home ranges to maximise reproductive success, whilst the 'nomadic' males were subordinate animals that were forced to range over a far greater area in search of unguarded females. We conclude that C. porosus are highly mobile animals existing within a complex social system, and mate/con-specific interactions are likely to have a profound effect upon population density and distribution, and an individual's travel potential. We recommend that impacts on socio-spatial behaviour are considered prior to the implementation of management interventions. PMID:23650510

  17. Supercritical Saltwater Spray for Marine Cloud Brightening (MCB)

    NASA Astrophysics Data System (ADS)

    Neukermans, A.; Cooper, G. F.; Foster, J.; Galbraith, L. K.; Johnston, D.; Ormond, B.; Wang, Q.

    2012-12-01

    Solar Radiation Management (SRM), including both stratospheric sulfur aerosol delivery and MCB, has emerged as the leading contender for geoengineering. Field research in MCB would require a technique capable of producing 1017 salt nuclei/sec from a single source on a seagoing vessel. Spraying supercritical saltwater has emerged as a viable technology, at least for research purposes. Under optimum conditions a single 50-μm nozzle produces 1014 suitable nuclei/sec. Power consumption is high (1-2 MW), but 95% of the required energy is in the form of heat that can probably be obtained from wasted ship-engine heat. While its implementation is conceptually simple, the corrosive nature of supercritical saltwater makes the material requirements very demanding. Progress on this work is detailed.

  18. Responses of Bruguiera gymnorrhiza to saltwater monitored by miniature electrodes.

    PubMed

    Sasaki, Satoshi; Chiba, Yosuke; Hanagata, Nobutaka

    2006-05-01

    We measured the voltage between two Ag/AgCl electrodes, one inserted into the seedling of the salt-tolerant plant Bruguiera gymnorrhiza and the other into the vermiculite in which the seedling was potted. Four seedlings were placed in different environments, in saltwater or pure water, with light or alternating light/dark conditions. We have found that (1) the voltage profiles showed periodical oscillatory behavior; (2) seedlings in saltwater showed higher voltage compared to the ones in pure water; (3) in the light environment, the voltage was higher compared to the one in the dark environment; (4) in the dark environment, a voltage wave was hardly observable; and (5) electrodes inserted into the propagule cortex, stem cortex, and petiole showed different voltage wave amplitudes. The voltage profiles will provide an effective way to evaluate the movement of salt water inside the salt-tolerant plant. PMID:16125474

  19. On a new benchmark for the simulation of saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Stoeckl, Leonard; Graf, Thomas

    2015-04-01

    To date, many different benchmark problems for density-driven flow are available. Benchmarks are necessary to validate numerical models. The benchmark by Henry (1964) measures a saltwater wedge, intruding into a freshwater aquifer in a rectangular model. The Henry (1964) problem of saltwater intrusion is one of the most applied benchmarks in hydrogeology. Modelling saltwater intrusion will be of major importance in the future because investigating the impact of groundwater overexploitation, climate change or sea level rise are of key concern. The worthiness of the Henry (1964) problem was questioned by Simpson and Clement (2003), who compared density-coupled and density-uncoupled simulations. Density-uncoupling was achieved by neglecting density effects in the governing equations, and by considering density effects only in the flow boundary conditions. As both of their simulations showed similar results, Simpson and Clement (2003) concluded that flow patterns of the Henry (1964) problem are largely dictated by the applied flow boundary conditions and density-dependent effects are not adequately represented in the Henry (1964) problem. In the present study, we compare numerical simulations of the physical benchmark of a freshwater lens by Stoeckl and Houben (2012) to the Henry (1964) problem. In this new benchmark, the development of a freshwater lens under an island is simulated by applying freshwater recharge to the model top. Results indicate that density-uncoupling significantly alters the flow patterns of fresh- and saltwater. This leads to the conclusion that next to the boundary conditions applied, density-dependent effects are important to correctly simulate the flow dynamics of a freshwater lens.

  20. Reclamation of saltwater-contaminated soil in Big Lake field

    SciTech Connect

    Weathers, M.L.; Moore, K.M.; Ford, D.L.; Curlee, C.K.

    1994-12-31

    Since the oil discovery at Santa Rita No. 1 in 1923, Big Lake in Reagan County, Texas, has produced 135 million bbl of oil and 1 billion bbl of saltwater. Until the early 1960`s, the accepted disposal method for saltwater was surface discharge to evaporation ponds north of the field. Approximately 200 million bbl of saltwater was discharged, resulting in 11 mi{sup 2} of barren landscape characterized by saline soils incapable of supporting vegetation. In 1989 an experimental project was initiated to reclaim 0.5 mi{sup 2} of affected area to rangeland productivity. An underground drainage system was installed to drain near-surface, salt-saturated perched water. Earthern terrances were constructed to reduce rainfall runoff and increase percolation to facilitate leaching of salts from the surface soil. Salt-saturated groundwater is drained by the system and pumped to injection wells for disposal. The excellent revegetation that has occurred over the test area after 2 years of operations is encouraging and has shown the need for enhancing the existing system with supplemental water from fresh-water wells, application of soil amending agents, and selective planting of salt-tolerant species.

  1. Saltwater circulation patterns within the freshwater-saltwater interface in coastal aquifers: Laboratory experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    Oz, Imri; Shalev, Eyal; Yechieli, Yoseph; Gvirtzman, Haim

    2015-11-01

    Groundwater flow patterns within the freshwater-saltwater interface in coastal aquifers include rotation in the flow direction of saltwater that originates from the sea and circulates in the aquifer. Using two types of tracer experiments we analyze the configuration of the rotating flow-lines. The experimental results are numerically reconstructed and quantitatively compared to the salinity distribution along the interface. The results show that the rotation in the direction of the saltwater flow-lines begins at the lowermost part of the interface (i.e. contour C/Cmax = 99%), and completes within its lower tenth (contour C/Cmax = 94%). At the upper part of the interface, after the rotation is completed, the flow is dictated by the freshwater flow seaward. Based on these results, the well-known chemical freshwater-saltwater interface is divided into two different parts, defined by their physical properties: (1) the lower part is the "Flow Rotation Region", defined by convective circulating flow-lines; and (2) the upper part is the "Dispersive Region", defined by dispersive dilution. Sensitivity analysis shows that the physical configuration of the interface depends on the transversal dispersivities. At higher dispersivities the rotation width increases, but completes within the lower third of the interface, at most. The sensitivity analysis also shows that the rotation begins at the lowermost part of the interface for dispersivities. Therefore, since no flow occurs below a line of 99%, the saline water that flows seaward is always diluted with respect to its original salinity. These flow patterns might affect coastal processes such as submarine groundwater discharge (SGD) and chemicals transport through the aquifer.

  2. Analysis of the polarization decay of coated steel in saltwater

    SciTech Connect

    Kumar, A.; Van Blaricum, V.

    1995-10-01

    The polarization decay of coated and bare steel specimens in saltwater was measured. A simple nested equivalent circuit with two ``RC`` constants was used to analyze the data. The values of the two ``RC`` constants were calculated for 2%, 20%, and 100% bare steel. A coated and scratched specimen with the bare area less than 1% was also analyzed with this procedure. It was observed that corroded steel specimens decay slower than the coated specimens. The decay rate decreased with the increase in bare area of coated steel. The pseudo capacitance values calculated from the time constants increased as the corroded bare area of coated steel was increased.

  3. Purification, characterization, and crystallization of Crocodylus siamensis hemoglobin.

    PubMed

    Jandaruang, Jinda; Siritapetawee, Jaruwan; Songsiriritthigul, Chomphunuch; Preecharram, Sutthidech; Azuma, Taoka; Dhiravisit, Apisak; Fukumori, Yoshihiro; Thammasirirak, Sompong

    2014-08-01

    Crocodylus siamensis hemoglobin was purified by a size exclusion chromatography, Sephacryl S-100 with buffer containing dithiothreitol. The purified Hb was dissociated to be two forms (α chain and β chain) which observed by SDS-PAGE, indicated that the C. siamensis Hb was an unpolymerized form. The unpolymerized Hb (composed of two α chains and two β chains) showed high oxygen affinity at 3.13 mmHg (P(50)) and 1.96 (n value), and a small Bohr effect (δH(+) = -0.29) at a pH of 6.9-8.4. Adenosine triphosphate did not affect the oxygenation properties, whereas bicarbonate ions strongly depressed oxygen affinity. Crude C. siamensis Hb solutions were showed high O(2) affinity at P(50) of 2.5 mmHg which may assure efficient utilization of the lung O(2) reserve during breath holding and diving. The purified Hbs were changed to cyanmethemoglobin forms prior crystallization. Rod- and plate-shaped crystals were obtained by the sitting-drop vapor-diffusion method at 5 °C using equal volumes of protein solution (37 mg/ml) and reservoir [10-13 % (w/v) PEG 4000, with 0.1 M Tris buffer in present of 0.2 M MgCl(2)·6H(2)O] solution at a pH of 7.0-8.5. PMID:24928538

  4. Changes in growth and osmoregulation during acclimation to saltwater in juvenile Amur sturgeon Acipenser schrenckii

    NASA Astrophysics Data System (ADS)

    Zhao, Feng; Zhuang, Ping; Zhang, Longzhen; Hou, Junli

    2010-05-01

    We evaluated the ability of juvenile Amur sturgeon ( Acipenser schrenckii) to osmoregulate and grow in saltwater. Hatchery-reared juveniles (mean weight 106.8 g, 5-month old) were transferred from freshwater to 10, 20, and 25 salinity saltwater over a period of 20 d. We measured the growth, serum osmolality, ion concentrations, and Na+/K+-ATPase activity. In addition, we prepared samples of gill tissue to quantify morphological changes in gill ultrastructure. Rearing in up to 25 saltwater for 30 d had no significant effect on growth. Similarly, serum osmolality and ion concentrations were similar to levels reported in other teleosts following acclimation to saltwater. Serum osmolality and Na+, Cl- concentrations increased significantly with the initial increase in salinity. Afterwards, levels tended to stabilize and then decrease. Serum K+ levels did not change during acclimation to saltwater. Gill Na+/K+-ATPase activity increased initially as salinity was increased. However, the activity later decreased and, finally stabilized at 3.7±0.1 μmol Pi/mg·prot·h in 25 saltwater (1.6 times higher than the level in those in freshwater). In fish that were held only in freshwater, the chloride cells were located in the interlamellar regions of the filament and at the base of the lamella. Following acclimation to 25 saltwater for 30 d, the number and size of chloride cells increased significantly. Our results suggest that juvenile Amur sturgeon is able to tolerate, and grow in, relatively high concentrations of saltwater.

  5. Effects of climate change on saltwater intrusion at Hilton Head Island, SC. U.S.A.

    USGS Publications Warehouse

    Payne, Dorothy F.

    2010-01-01

    Sea‐level rise and changes in precipitation patterns may contribute to the occurrence and affect the rate of saltwater contamination in the Hilton Head Island, South Carolina area. To address the effects of climate change on saltwater intrusion, a threedimensional, finite‐element, variable‐density, solute‐transport model was developed to simulate different rates of sea‐level rise and variation in onshore freshwater recharge. Model simulation showed that the greatest effect on the existing saltwater plume occurred from reducing recharge, suggesting recharge may be a more important consideration in saltwater intrusion management than estimated rates of sea‐level rise. Saltwater intrusion management would benefit from improved constraints on recharge rates by using model‐independent, local precipitation and evapotranspiration data, and improving estimates of confining unit hydraulic properties.

  6. Modeling Saltwater Intrusion in Highly Heterogeneous Coastal Aquifers

    NASA Astrophysics Data System (ADS)

    Safi, A.; El-Fadel, M.; Doummar, J.; Abou Najm, M.; Alameddine, I.

    2015-12-01

    In this study, a 3D variable-density flow and solute transport model SEAWAT was used to examine the impact of macroscopic variation in a soil matrix on widening or narrowing the thickness of the saltwater-freshwater mixing zone. Located along the Eastern Mediterranean (Beirut), the pilot aquifer consists of karstified limestone of Cretaceous age overlain by Upper Tertiary and Quaternary unconsolidated deposits. The model used the advanced pilot-points parameterization coupled with PEST to characterize spatial heterogenieity. Historically simulated water levels were relied upon to reduce potential numerical instabilities induced by insensitive parameters in transient calibration. The latter demonstrated a high degree of heterogeneity in the middle parts of the aquifer and along western coastlines with specification of a high hydraulic conductivity and low storativity in fault networks. The response of the aquifer to seasonal stresses such as climate cycles, pumping rates and recharge rates was manifested as high fluctuations in potentiometric surface due to potential fast flow pathways along faults. The final distribution of saltwater intrusion supports two mechanisms 1) lateral encroachment of recent seawater into the western zone of the aquifer which is of most concern due to high horizontal hydraulic conductivity in the wave direction and 2) upconing in the northwest and southwest of the aquifer due to large vertical hydraulic conductivities that tend to exacerbate the vertical movement of salinity.

  7. Bubble size distribution under saltwater and freshwater breaking waves

    NASA Astrophysics Data System (ADS)

    Cartmill, John W.; Yang Su, Ming

    1993-11-01

    The chemical composition of salt water profoundly alters the process of microbubble formation and must be accounted for in extrapolating freshwater results to the ocean environment. Results are presented of the measurement of bubble size distributions generated by breaking waves in both freshwater and saltwater laboratory tanks. Bubble radii in the range of 34-1200 μ m were measured by an acoustic resonator at various positions and depths in a large-scale wave tank at Oregon State University. This experiment represents the first attempt to measure bubbles produced by breaking waves at this large scale in a saltwater tank. Mechanically generated wave groups, with maximum wave height of 4 ft, were used to produce breaking waves and bubble plumes comparable in scale with moderate ocean waves. During the experiment salt was added to bring the salinity of the water to 30%. This salinity alters the nature of the bubbles produced and their subsequent evolution. An order of magnitude increase in the number density over the entire size range was observed for salt water vs. fresh water.

  8. Biological observations on the crocodile shark Pseudocarcharias kamoharai.

    PubMed

    Dai, X J; Zhu, J F; Chen, X J; Xu, L X; Chen, Y

    2012-04-01

    Sex ratios and gravid characteristics were analysed for the crocodile shark Pseudocarcharias kamoharai from the tropical eastern Pacific Ocean. Gravid females ranged from 80 to 102 cm fork length (L(F) ). The mode litter size was four (two embryos per uterus), mean embryo length was linearly correlated with maternal length (r = 0·465, n = 32); there was no significant difference in L(F) between female and male embryos. PMID:22497379

  9. Mechanics of fragmentation of crocodile skin and other thin films.

    PubMed

    Qin, Zhao; Pugno, Nicola M; Buehler, Markus J

    2014-01-01

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin. PMID:24862190

  10. Mechanics of fragmentation of crocodile skin and other thin films

    PubMed Central

    Qin, Zhao; Pugno, Nicola M.; Buehler, Markus J.

    2014-01-01

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin. PMID:24862190