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PubMedDate not supplied

Biotic and abiotic factors affect the nest environment of embryonic leatherback turtles, Dermochelys coriacea.

Clutches of leatherback turtles, Dermochelys coriacea, have lower hatching success than those of other sea turtles, but causes of high embryonic mortality are unknown. We measured characteristics of clutches along with spatial and temporal changes in PO(2) and temperature during incubation to determine the extent to which they affected the developmental environment of leatherback embryos. Minimum PO(2) in nests decreased as both the total number and mass of metabolizing embryos increased. Increases in both the number and mass of metabolizing embryos caused an increase in maximum nest temperature. However, neither PO(2) nor temperature was correlated with hatching success. Our measurements of relatively high nest PO(2) (lowest 17.1 kPa or 16.9% O(2)) indicate that hypoxia apparently does not cause the low hatching success of leatherback clutches. Oxygen partial pressure increased and temperature decreased from the center toward the periphery of leatherback nests. We inferred from these measurements that positions of eggs within nests vary in quality and potentially affect overall developmental success of entire clutches. The large metabolic mass of leatherback clutches and limits to gas flux imposed by the sand create a situation in which leatherback embryos collectively affect their own environment.

Animals↗
PubMed1999

Sources of Vibrio mimicus contamination of turtle eggs.

Vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (Lepidochelys olivacea) at Ostional anidation beach, Costa Rica. Statistical analysis supports that eggs are contaminated with V. mimicus by contact with the sand nest. V. mimicus was isolated from eggs of all nests tested, and ctxA+ strains were found in 31% of the nests, all of which were near the estuary.

Animals↗
PubMed1988

Purification and characterization of alpha-macroglobulin and ovomacroglobulin of the green turtle (Chelonia mydas japonica).

The plasma alpha-macroglobulin and egg white ovomacroglobulin were purified from the sea turtle, Chelonia mydas japonica, and their structural and functional properties were studied with the aim of clarifying the degree of evolutional divergence of two homologous proteins specific to different tissues of the same animal. The concentration of alpha-macroglobulin in green turtle plasma was about 4 mg/ml. The protein was purified from the plasma by precipitation with polyethylene glycol 6000, followed by zinc chelate chromatography and gel chromatography on Sepharose CL-6B. The concentration of ovomacroglobulin in green turtle egg white was about 0.4 mg/ml. Ovomacroglobulin was purified by gel chromatography on Sepharose CL-6B. The two proteins had similar molecular weights and amino acid compositions, and both inhibited proteinases such as trypsin, chymotrypsin, papain, and thermolysin. The amino terminal sequences of the two proteins were homologous to each other but higher homologies were found between the ovomacroglobulin of turtle and chicken, and between the serum macroglobulins of the same animals. The functional difference between turtle alpha-macroglobulin and ovomacroglobulin became clear when they were treated with methylamine, which is known to destroy the inhibitory activity of human alpha 2-macroglobulin by splitting internal thiolester bonds. The inhibitory activity of the turtle plasma protein was completely destroyed by methylamine but that of ovomacroglobulin was only partially affected. The number of sulfhydryl groups as titrated with 5,5'-dithiobis(2-nitrobenzoate) before and after treatment with proteinases or methylamine was different for the two proteins. The amount of radioactive methylamine that was incorporated was also different between the two proteins. The two proteins purified in this study had no immunological cross-reactivity.

Amino Acid Sequence↗
PubMed1964

INTERCELLULAR CHANNELS IN THE SALT-SECRETING GLANDS OF MARINE TURTLES.

Long, pleomorphic microvilli project from the walls of adjacent secretory cells in the lacrymal glands of sea turtles, and a substance identified histochemically as a mucopolysaccharide fills the intercellular channels. These features are not characteristic of the principal secretory cells in the salt glands of marine birds.

Animals↗
PubMed1999

An outbreak of salmonellosis linked to a marine turtle.

In September 1998, an outbreak of gastroenteritis occurred in a coastal Aboriginal community in the Northern Territory over a seven day period. An investigation was conducted by the Center for Disease Control, Territory Health Services. Thirty-six cases were detected and 17% (n=6) were hospitalized. Salmonella chester was isolated from eight of nine stool specimens. Sixty-two percent of cases interviewed (n=28) reported consumption of a green turtle (Chelonia mydas) within a median of 24 hours prior to onset of illness. Of the remainder, all but two were contacts of other cases. Salmonella chester was isolated from a section of partially cooked turtle meat. There are no previous published reports of salmonellosis associated with consumption of sea turtles despite them being a popular food source in coastal communities in the Pacific.

Adolescent↗
PubMed2006

Egg components, egg size, and hatchling size in leatherback turtles.

Relationships between egg size, egg components, and neonate size have been investigated across a wide range of oviparous taxa. Differences in egg traits among taxa reflect not only phylogenetic differences, but also interactions between biotic (i.e., maternal resource allocation) and abiotic (i.e. nest environment conditions) factors. We examined relationships between egg mass, egg composition, and hatchling size in leatherback turtles (Dermochelys coriacea) because of the unique egg and reproductive characteristics of this species and of sea turtles in general. Albumen comprised 63.0%+/-2.8% (mean+/-S.D.) of egg mass and explained most of the variation in egg mass, whereas yolk comprised only 33.0%+/-2.7%. Additionally, leatherback albumen dry mass was approximately 16% of albumen wet mass. Whereas hatchling mass increased significantly with egg mass (n = 218 clutches), hatchling mass increased by only approximately 2 g for each 10 g increase in egg mass and was approximately 10-20 g greater than yolk mass. Taken together, our results indicate that albumen might play a particularly significant role in leatherback embryonic development, and that leatherback eggs are both capable of water uptake from the nest substrate and also possess a large reservoir of water in the albumen. Relationships between egg mass and egg components, such as variation in egg mass being largely explained by variation in albumen mass and egg mass containing a relatively high proportion of albumen solids, are more similar to bird eggs than to eggs of other non-avian reptiles. However, hatchling mass correlates more with yolk mass than with albumen mass, unlike patterns observed in bird eggs of similar composition.

Animals↗
PubMed2005

Fibropapillomatosis in stranded green turtles (Chelonia mydas) from the eastern United States (1980-98): trends and associations with environmental factors.

We examined data collected by the US Sea Turtle Stranding and Salvage Network on 4,328 green turtles (Chelonia mydas) found dead or debilitated (i.e., stranded) in the eastern half of the USA from Massachusetts to Texas during the period extending from 1980 to 1998. Fibropapillomatosis (FP) was reported only on green turtles in the southern half of Florida (south of 29 degrees N latitude). Within this region, 22.6% (682/3,016) of the turtles had tumors. Fibropapillomatosis was more prevalent in turtles found along the western (Gulf) coast of Florida (51.9%) than in turtles found along the eastern (Atlantic) coast of Florida (11.9%) and was more prevalent in turtles found in inshore areas (38.9%) than in turtles found in offshore areas (14.6%). A high prevalence of FP corresponded to coastal waters characterized by habitat degradation and pollution, a large extent of shallow-water area, and low wave energy, supporting speculation that one or more of these factors could serve as an environmental cofactor in the expression of FP. A high prevalence of FP did not correspond to high-density green turtle assemblages. Turtles with tumors were found most commonly during the fall and winter months, and the occurrence of tumors was most common in turtles of intermediate size (40-70-cm curved carapace length). Stranded green turtles with tumors were more likely to be emaciated or entangled in fishing line and less likely to have propeller wounds than were stranded green turtles without tumors. Turtles with and without tumors were equally likely to show evidence of a shark attack. The percent occurrence of tumors in stranded green turtles increased from approximately 10% in the early 1980s to over 30% in the late 1990s. Fibropapillomatosis was first documented in southernmost Florida in the late 1930s and spread throughout the southern half of Florida and the Caribbean during the mid-1980s. Because green turtles living in south Florida are known to move throughout much of the Caribbean, but are not known to move to other parts of the USA or to Bermuda, the spread and current distribution of FP in the western Atlantic, Gulf of Mexico, and Caribbean can be explained by assuming FP is caused by an infectious agent that first appeared in southern Florida. Aberrant movements of captive-reared turtles or of turtles that are released into areas where they were not originally found could spread FP beyond its current distribution.

Animals↗
PubMed2003

Bacteraemia in free-ranging Hawaiian green turtles Chelonia mydas with fibropapillomatosis.

Past studies of free-ranging green turtles Chelonia mydas with fibropapillomatosis (FP) in Hawaii have shown that animals become immunosuppressed with increasing severity of this disease. Additionally, preliminary clinical examination of moribund turtles with FP revealed that some animals were also bacteraemic. We tested the hypothesis that bacteraemia in sea turtles is associated with the severity of FP. We captured free-ranging green turtles from areas in Hawaii where FP is absent, and areas where FP has been endemic since the late 1950s. Each turtle was given an FP severity score ranging from 0 (no tumours) to 3 (severely affected). A fifth category included turtles that were stranded ashore and moribund with FP. We found that the percentage of turtles with bacteraemia increased with the severity of FP, and that the majority of bacteria cultured were Vibrio spp. Turtles with severe FP were more susceptible to bactaeremia, probably in part due to immunosuppression. The pattern of bacteraemia in relation to severity of disease strengthens the hypothesis that immunosuppression is a sequel to FP.

Animals↗
PubMed2000

[Identification of turtle shell, tortoise plastron and their counterfeit products].

OBJECTIVE: To identify the commercial Chinese medicines turtle shell and tortoise plastron. METHOD: Morphological identification and differential thermal analysis (DTA). RESULT: 2 kinds of counterfeit turtle shell and 3 kinds of counterfeit tortoise plastron were found, and their morphological and DTA identification features were proposed. CONCLUSION: Sea turtle shells presently on the market are sham commodities of turtle shell, which derive from Lissemys punctata and Pelochelys bibroni indigenous to south Asia, while plastrons of Ocadia sinensis, Chelonia mydas and Lepidochelys olivacea are counterfeit products of tortoise plastron. Turtle shells, tortoise plastrons and their counterfeit products may be exactly distinguished by morphological and DTA features.

Animals↗
PubMed2003

Predator diversity hotspots in the blue ocean.

Concentrations of biodiversity, or hotspots, represent conservation priorities in terrestrial ecosystems but remain largely unexplored in marine habitats. In the open ocean, many large predators such as tunas, sharks, billfishes, and sea turtles are of current conservation concern because of their vulnerability to overfishing and ecosystem role. Here we use scientific-observer records from pelagic longline fisheries in the Atlantic and Pacific Oceans to show that oceanic predators concentrate in distinct diversity hotspots. Predator diversity consistently peaks at intermediate latitudes (20-30 degrees N and S), where tropical and temperate species ranges overlap. Individual hotspots are found close to prominent habitat features such as reefs, shelf breaks, or seamounts and often coincide with zooplankton and coral reef hotspots. Closed-area models in the northwest Atlantic predict that protection of hotspots outperforms other area closures in safeguarding threatened pelagic predators from ecological extinction. We conclude that the seemingly monotonous landscape of the open ocean shows rich structure in species diversity and that these features should be used to focus future conservation efforts.

Animals↗
PubMed2004

Evaluation of magnetic resonance imaging for detection of internal tumors in green turtles with cutaneous fibropapillomatosis.

OBJECTIVE: To describe the gross cross-sectional anatomy of green turtles (Chelonia mydas) and evaluate magnetic resonance imaging (MRI) for detection of internal tumors in green turtles with cutaneous fibropapillomatosis. DESIGN: Prospective study. ANIMALS: 3 dead green turtles, 1 healthy green turtle, and 8 green turtles with cutaneous fibropapillomatosis. PROCEDURES: Gross cross-sectional anatomy of a dead turtle was described. Each live turtle underwent a complete physical examination, and dorsoventral whole-body survey radiographic views were obtained. Magnetic resonance imaging was performed in dorsal and transverse planes. Radiographs and magnetic resonance images were examined for evidence of internal nodules. Results were compared with necropsy findings in 5 of 8 turtles. RESULTS: Nodules in the lungs of 2 turtles were detected via radiography, whereas pulmonary nodules were detected in 5 turtles via MRI. No other visceral nodules were detected via radiography; however, masses in the stomach and adjacent to the bladder and kidneys were detected in 1 turtle via MRI. Other extrapulmonary abnormalities observed at necropsy were not detected on MR images. CONCLUSIONS AND CLINICAL RELEVANCE: MRI may be valuable for detection of internal tumors in green turtles with cutaneous fibropapillomatosis. Nodules were more apparent in the lungs than in other organs. Results of MRI may serve as prognostic indicators for sea turtles undergoing assessment, treatment, and rehabilitation. Clinical application may be limited by cost and availability of MRI technology.

Animals↗
PubMedDate not supplied

Modern CT applications in veterinary medicine.

Although computed tomography (CT) is used primarily for diagnosis in humans, it can also be used to diagnose disease in veterinary patients. CT and associated three-dimensional reconstruction have a role in diagnosis of a range of illnesses in a variety of animals. In a sea turtle with failure to thrive, CT showed a nodal mass in the chest, granulomas in the lungs, and a ball in the stomach. CT of a sea dragon with balance and movement problems showed absence of the swim bladder. In a sloth with failure to thrive, CT allowed diagnosis of a coin in the intestine. CT of a puffin with failure to thrive showed a mass in the chest, which was found to be a hematoma. In a smooth-sided toad whose head was tilted to one side and who was circling in that direction, CT showed partial destruction of the temporal bone. CT of a domestic cat with listlessness showed a mass with focal calcification, which proved to be a leiomyosarcoma. CT of a sea otter showed pectus excavatum, which is caused by the animal smashing oysters against its chest. In a Japanese koi with abdominal swelling, CT allowed diagnosis of a hepatoma.

Animals↗
PubMed2005

Epizootiology of spirorchiid infection in green turtles (Chelonia mydas) in Hawaii.

We describe the epizootiology of spirorchiid trematode infections in Hawaiian green turtles (Chelonia mydas) by quantifying tissue egg burdens in turtles submitted for necropsy and by assessing antibody response to crude adult worm and egg antigens among a variety of age groups. Hapalotrema sp. and Laeredius sp. predominated in turtles infected with spirorchiids. Tissue egg burdens decreased with increasing size and increased with deteriorating body condition of turtles. No relationship was found between tissue egg burdens and sex or fibropapillomatosis status. Tissue egg burdens increased in turtles from southeast to northwest in the main Hawaiian Islands (Hawaii to Kauai). Hatchling and captive-reared turtles had significantly lower levels of antibodies against crude worm and egg antigens. Based on tissue egg burdens and antibody status, we hypothesize that immature turtles become infected with spirorchiids shortly after recruiting into coastal foraging pastures from the pelagic environment, that infection levels decrease with age, and that spirorchiids detrimentally affect the body condition of sea turtles independent of tumor burden. The low intensity of infection in turtles with the endemic trematode Carettacola hawaiiensis suggests either that turtles are less susceptible to infection with this parasite or that the parasite is outcompeted by species of Hapalotrema and Laeredius. Given that the 2 latter species are found in the Pacific and other oceans, they are not likely endemic and were probably introduced into Hawaii through an undetermined route.

Animals↗
PubMed2003

Lung ventilation during treadmill locomotion in a terrestrial turtle, Terrapene carolina.

The limb girdles and lungs of turtles are both located within the bony shell, and therefore limb movements during locomotion could affect breathing performance. A mechanical conflict between locomotion and lung ventilation has been reported in adult green sea turtles, Chelonia mydas, in which breathing stops during terrestrial locomotion and resumes during pauses between bouts of locomotion. We measured lung ventilation during treadmill locomotion using pneumotach masks in three individual Terrapene carolina (mass 304-416 g) and found no consistent mechanical effects of locomotion on breathing performance. Relatively small tidal volumes (2.2+/-1.4 ml breath(-1); mean +/- S.D., N=3 individuals) coupled with high breath frequencies (36.6+/-26.4 breaths min(-1); mean +/- S.D., N=3 individuals) during locomotion yield mass-specific minute volumes that are higher than any previously reported for turtles (264+/-64 ml min kg(-1); mean +/- S.D., N=3 individuals). Minute volume was higher during locomotion than during recovery from exercise (P<0.01; paired t-test), and tidal volumes measured during locomotion were not significantly different from values measured during brief pauses between locomotor bouts or during recovery from exercise (P>0.05; two-way ANOVA). Since locomotion does not appear to conflict with breathing performance, the mechanism of lung ventilation must be either independent of, or coupled to, the stride cycle. The timing of peak airflow from breaths occurring during locomotion does not show any fixed phase relationship with the stride cycle. Additionally, the peak values of inhalatory and exhalatory airflow rates do not differ consistently with respect to the stride cycle. Together, these data indicate that T. carolina is not using respiratory-locomotor coupling and limb and girdle movements do not contribute to lung ventilation during locomotion. X-ray video recordings indicate that lung ventilation is achieved via bilateral activity of the transverse (exhalatory) and oblique (inhalatory) abdominal muscles. This specialized abdominal ventilation mechanism may have originally circumvented a mechanical conflict between breathing and locomotion in the ancestor of turtles and subsequently allowed the ribs to abandon their role in lung ventilation and to fuse to form the shell.

Abdominal Muscles↗
PubMed1988

Polymerization of turtle alpha-macroglobulin through newly exposed sulfhydryls reveals the location of ex-thiolester bonds.

Green turtle alpha-macroglobulin, which has previously been shown to contain thiolester bonds, formed linear polymers after being treated with proteinases. Biochemical analyses showed that the polymerization proceeded through disulfide-bond formation between monomers. The only sulfhydryl groups available for such polymerization after proteinase treatment were those created as the product of thiolester hydrolysis. Electron micrographs of polymers revealed H-shaped monomeric units aligned lengthwise in linear polymers. The average length per monomeric unit in the polymer estimated from the discrete distribution of polymer lengths was approximately 80% of the average length of free monomers, indicating that monomers overlapped each other within a region of about 4 nm. From such observations we concluded that the newly produced sulfhydryl groups were located on the four arms of the H-shaped molecule. The location of sulfhydryls can be taken as the site of the exposure of thiolesters which were originally sequestered in the hydrophobic interior of the molecule. Since the structure of turtle alpha-macroglobulin is very similar to that of human serum alpha 2-macroglobulin the results predict a similar location of sulfhydryls in human alpha 2-macroglobulin after proteinase treatment. The observed polymerization property is unique to sea turtle alpha-macroglobulin and has not been observed with human alpha 2-macroglobulin or other homologous proteins.

Animals↗
PubMedDate not supplied

Hybridization among the ancient mariners: characterization of marine turtle hybrids with molecular genetic assays.

Reports of hybridization between marine turtle species (family Cheloniidae) have been difficult to authenticate based solely on morphological evidence. Here we employ molecular genetic assays to document the sporadic, natural occurrence of viable interspecific hybrids between species representing four of the five genera of cheloniid sea turtles. Using multiple DNA markers from single-copy nuclear loci, eight suspected hybrids (based on morphology) were confirmed to be the products of matings involving the loggerhead turtle (Caretta caretta) x Kemp's ridley (Lepidochelys kempii) (N = 1 specimen), loggerhead turtle x hawksbill (Eretmochelys imbricata) (N = 2), loggerhead turtle x green turtle (Chelonia mydas) (N = 4), and green turtle x hawksbill (N = 1). Molecular markers from mitochondrial DNA permitted identification of the maternal parental species in each cross. The species involved in these hybridization events represent evolutionary lineages thought to have separated 10-75 million years ago (mya) and thus may be among the oldest vertebrate lineages capable of producing viable hybrids in nature. In some cases, human intervention with the life cycles of marine turtles (e.g., through habitat alteration, captive rearing, or attempts to establish new breeding sites) may have increased the opportunities for interspecific hybridization.

Animals↗
PubMed1997

31P-NMR determinations of cytosolic phosphodiesters in turtle hearts.

As part of our ongoing research on cardiac hypoxia tolerance we have conducted 31P nuclear magnetic resonance (NMR) studies of isolated, perfused, working hearts from freshwater turtles, animals that are well known for their ability to tolerate prolonged periods of anoxia. A striking feature of turtle heart spectra is an extremely high concentration of NMR visible phosphodiesters (PDEs). Cardiac spectra from mammals, on the other hand, typically exhibit only a small resonance in the PDE region. Our aim in this study was to compare myocardial PDE profiles between the highly hypoxia tolerant western painted turtle (Chrysemys picta bellii) and the relatively hypoxia sensitive softshelled turtle (Trionyx spinifer) in order to begin to rest the hypothesis that high constitutive levels of cytosolic PDEs may play a role in conferring hypoxia and ischemia tolerance on the myocardium. We also collected 31P-NMR spectra of PCA extracts of tissue from these species and from Kemp's ridley sea turtles (Lepidochelys kempi), as well as spectra from isolated hearts and PCA extracts of red-eared sliders (Trachemys [formerly Pseudemys] scripta]). Total NMR visible phosphodiesters make up 24 +/- 8.6% of the total NMR visible phosphorus in Chrysemys hearts, 20.7 +/- 5.9% in Trachemys hearts, but only 12.2 +/- 5.1% in Trionyx hearts (P < 0.05). We have identified three distinct PDEs in turtle hearts: glycerophosphorylcholine (GPC); glycerophosphorylethanolamine (GPE); and serine ethanolamine phosphodiester (SEP). SEP is the dominant compound in Chrysemys and Trachemys (79.3 +/- 10.2% and 84.7 +/- 3.7% of total PDE, respectively), while GPC is most abundant in Trionyx (74.0 +/- 4.3% of total PDE) and Lepidochelys (not quantitated). The function of this class of compounds is unclear but it has been suggested that cytosolic PDEs may function as lysophospholipase inhibitors, a role that would decrease the rate of membrane phospholipid turnover. Our comparative data suggest that cytosolic PDEs could play a role in phospholipid sparing during anoxic or ischemic stress in turtles but a direct test of this hypothesis awaits future experimentation.

Animals↗
PubMed1998

The environmental contaminant DDE fails to influence the outcome of sexual differentiation in the marine turtle Chelonia mydas.

In many turtles, the temperature experienced during the middle of egg incubation determines the sex of the offspring. The implication of steroid sex hormones as the proximate trigger for sex determination opens the possibility that endocrine-disrupting contaminants may also influence the outcome of sexual differentiation. In this study we investigate the potential effects of DDE (a common DDT metabolite) on sexual differentiation of Chelonia mydas (green sea turtle). Four clutches of eggs collected from Heron Island, Queensland, Australia, were treated with DDE at the beginning of the thermosensitive period for sexual determination. An incubation temperature of 28 degrees C or less produces male hatchlings in this species, whereas 30 degrees C or more produces female hatchlings. Dosed eggs were consequently incubated at two temperatures (27.6 degrees C and 30.4 degrees C) on the upper and lower boundaries of the sex determination threshold for this species. DDE, ranging from 3.3 to 66.5 microg, was dissolved in 5, 10, and 25 microl ethanol and applied to eggshells above the embryo. Less than 2.5 ng/g DDE was present in eggs prior to dosing. Approximately 34% of the applied DDE was absorbed in the eggs, but only approximately 8% of applied DDE was found in embryos. Thus, treated eggs, corrected for background DDE, had up to 543 ng/g DDE. The sex ratio at these doses did not differ from what would be expected on consideration of temperature alone. Incubation time, hatching success, incidence of body deformities, hatching size, and weight were also within the limits of healthy developed hatchlings. This indicates that the eggs of C. mydas in the wild with concentrations of DDE less than 543 ng/g should produce hatchlings with relatively high hatching success, survival rate, and normally differentiated gonads.

Animals↗