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At least 883 records · Page 49Linked to original sources
PubMed1991

Effects of mercury, selenium, and organochlorine contaminants on reproduction of Forster's terns and black skimmers nesting in a contaminated Texas Bay.

Mean mercury (0.40 micrograms/g), and geometric mean DDE (1.6 micrograms/g) and polychlorinated biphenyl (PCB) (2.3 micrograms/g) concentrations in Forster's tern (Sterna forsteri) eggs from Lavaca Bay were higher than those in tern eggs from a reference area in San Antonio Bay, but residues were not correlated with hatching success. Nest success was similar between bays. Selenium levels in Lavaca Bay tern eggs (0.71 micrograms/g) were also comparable to those in eggs from the reference area (0.68 micrograms/g). Clutch size (3.1 to 3.4) of Lavaca Bay black skimmers (Rynchops niger) was no different than that (3.4) at a reference colony near Laguna Vista. Nest success was similar among three Lavaca Bay colonies, but success was lower at one Lavaca Bay colony (40%) than at Laguna Vista (65%). Mean mercury (0.46 micrograms/g) and selenium (0.75 micrograms/g) concentrations in skimmer eggs from Lavaca Bay were higher than those (0.19, 0.33 micrograms/g) from Laguna Vista; however, concentrations of neither contaminant were related to hatching success. DDE concentrations in Lavaca Bay skimmer eggs (3.4 micrograms/g) were similar to those from Laguna Vista (3.2 micrograms/g) and DDE was negatively correlated with hatching success. PCBs were higher in eggs from Lavaca Bay (1.3 micrograms/g) than Laguna Vista (0.8 micrograms/g). Organochlorine and metal contaminants in most eggs were below embryotoxic levels. Eggshell thinning in Forster's terns (7%) and black skimmers (5%) was below that associated with lowered reproduction. DDE and PCBs were detected in 9 Caspian tern (S. caspia) eggs; maximum concentrations were 4.7 and 5.4 micrograms/g. Caspian tern and least tern (S. albifrons) eggs contained low (less than or equal to 0.9 micrograms/g) concentrations of mercury and selenium.

Animals↗
PubMed1989

Onset of vitellogenin production and vitellogenesis, and their relationship to changes in the midgut epithelium and oocytes in the tick Dermacentor variabilis.

In Dermacentor variabilis (Say), the onset of vitellogenin production and vitellogenesis (uptake of vitellogenin into oocytes) began during the rapid-engorgement feeding period. Mating was required for both vitellogenin production and vitellogenesis to complete the tick's life cycle. Complete immunological identity, as measured by Ouchterlony's double diffusion test, existed between vitellogenin from the fat body, midgut and hemolymph, and vitellin from the ovaries and eggs. Antivitellin antibody did not react with host hemoglobin nor with fat body, midgut, and ovary extracts from feeding females prior to rapid engorgement, feeding unmated females, or unfed or fed males. Some unmated females fed for 13 days and then hand-detached from the host eventually began oviposition after going through a preoviposition period. In these ticks, organ extracts from the midgut, fat body and ovary reacted with antivitellin antibody. The presence or absence of presumed vitellogenic cells in the midgut and yolk bodies in oocytes corresponded with the presence or absence of vitellogenin and vitellogenesis as measured by Ouchterlony's test. Presumed vitellogenic cells increased in size during the preoviposition period. These cells reached their greatest size during the time when the most eggs were being produced, and then declined in size toward the end of oviposition. Vitellogenin was deposited directly into developing yolk bodies in oocytes and was not processed through lysosomes. Feeding was the process that initiated the formation of eggshell cuticle. Detachment from the host was required for the initiation of oviposition.

Animals↗
PubMed1993

[ESR and HPLC studies of the detection of gamma irradiation of eggs].

Two methods for the identification of irradiated eggs are presented. Electron spin resonance (ESR) detects radiation-specific radicals in the calcite matrix of eggshells. ESR gives unequivocal results for doses clearly below the technologically relevant dose. The stability of the radical in the calcite matrix was tested over a period of 6 weeks. Products that contain no or only low amounts of fat but a high percentage of protein can be identified by HPLC. Only in the chromatograms of irradiated samples is a peak of the amino acid ortho-tyrosine present. This HPLC method may be of great interest especially for the identification of irradiated pasteurized liquid egg white.

Amino Acids↗
PubMed1989

An immune response-dependent mechanism for the vertical transmission of an entomopathogen.

An exceptionally efficient mechanism for the vertical transmission of a parasitic gregarine is dependent on the insect host's immune response. Gametocysts of Ascogregarina chagasi on the genital accessory glands of adult female sand flies (Lutzomyia longipalpis) become encapsulated through hemocyte-mediated immune reactions. Oocysts of A. chagasi, ejected into the lumen of the glands owing to pressure exerted by this capsule, become glued to eggshells and are subsequently ingested by larvae. In L. longipalpis with an experimentally suppressed encapsulation reaction, fewer accessory glands contained oocysts of A. chagasi.

Animals↗
PubMed1985

Cardiomyopathy and vitamin E deficiency in zoo animals and birds.

Cardiomyopathy associated with vitamin E deficiency was diagnosed in more than 100 ruminants and primates and in 106 embryos and newly hatched chicks and ducklings. Affected bird embryos failed to pip the eggshell and died inside. Newly hatched chicks and ducklings and neonatal ruminants were weak, had difficulty standing or rising, and died within a few days. Death usually occurred without premonitory signs of disease in juvenile and adult animals. On gross examination, the hearts of the neonatal ruminants had areas of mottled, pinkish-tan myocardium. The hearts of the embryos and newly hatched birds were edematous, pinkish, and pale. In the juvenile ruminants, irregular, whitish patches or pale areas were seen in the myocardium. Histologically, there was multifocal myocytolysis in the myocardium of the neonatal and juvenile ruminants and embryos and newly hatched birds. Focal disseminated or diffuse myocardial fibrosis and myocytolysis were observed in the hearts of the adult animals. Plasma alpha tocopherol values were low enough in all species to be considered deficient. These values increased significantly after the addition of alpha tocopherol and/or vitamin E to the diets of the animals. Cardiomyopathy has not been diagnosed in any of the same groups of animals since supplementation was initiated.

Animals↗
PubMed1983

The role of vitamin D in the medullary bone formation in egg-laying Japanese quail and in immature male chicks treated with sex hormones.

The effect of vitamin D3 on medullary bone formation was investigated in egg-laying Japanese quail and in immature male chicks treated with sex hormones. When laying quail were fed a vitamin D-deficient diet for 16 days, their eggshell weights and egg production rate were markedly reduced in a time-dependent manner with a significant decrease in plasma calcium and 25-hydroxyvitamin D3 levels. The calcium content of the medullary bone of femurs decreased markedly with the progress of vitamin D deficiency, whereas that of the cortical bone remained unchanged. Quantitative histological examination also showed that the area of the mineralized portion of medullary bone in quail that were fed the vitamin D-deficient diet markedly decreased compared with that in the control laying quail, whereas the total area of the mineralized and unmineralized portions of medullary bone in the bone marrow cavity increased moderately. Daily administration of vitamin D3 (0.75 microgram/day) to the vitamin D-deficient quail increased the mineralization of medullary bone as early as day 4. Daily administration of both estradiol (0.3 mg/day) and testosterone (0.9 mg/day) for 3 weeks to immature male chicks induced an apparent hypercalcemia and matrix formation of medullary bone, regardless of the vitamin D status of the chicks. Mineralization of medullary bone was observed only when vitamin D3 was administered together with the sex hormones. These results suggest that vitamin D3 is directly involved in the mineralization of medullary bone in birds.

Animals↗
PubMed1981

Crystal orientation in the shell of the domestic fowl: an electron diffraction study.

The eggshell of the domestic fowl has been studied by transmission electron microscopy and diffraction. Thin sections of shell were prepared by chemical and ion-beam thinning techniques. Each calcite column of the palisade layer consisted of crystallites of diameter 20 to 30 micrometer with some tendency for crystallite alignment within a single column. Evidence indicates that there was no significant preferred orientation in the palisade layer as a whole. Only in the surface layer was any preferred orientation detected, and here (1014) planes tended to lie parallel to the surface. The results are compared with previously published data, and calcite nucleation and growth are discussed.

Animals↗
PubMed1989

Noninvasive heart rate monitoring system for avian embryos based on the ballistocardiogram.

A noninvasive heart rate (HR) monitoring system for avian embryos has been developed based on the ballistocardiogram (BCG). The BCG was detected using a phonograph cartridge as a record of the velocity of the minute ballistic movements of the eggshell, which are generated by recoil and impact of heart contraction and blood ejection. The autocorrelation coefficients (ACCs) of the detected signal were computed to confirm whether the detected signal contained ballistic movement. An envelope of ACC was calculated by the monitoring system to measure the intervals between peaks and/or highly correlated parts in the ACC, and then the system obtained HR by measuring these intervals. To demonstrate the valid range of the detecting method, the BCGs of chickens and Japanese quail embryos of different ages were measured. The result of the experiment shows that the BCGs of chickens and quail embryos are detected fully after about two-thirds of the incubation period has passed. The monitoring system will enable us to perform long-term HR measurement for developing avian embryos up to hatching.

Animals↗
PubMed1997

Ballistocardiogram of avian eggs determined by an electromagnetic induction coil.

As an avian embryo grows within an eggshell, the whole egg is moved by embryonic activity and also by the embryonic heartbeat. A technical interest in detecting minute biological movements has prompted the development of techniques and systems to measure the cardiogenic ballistic movement of the egg or ballistocardiogram (BCG). In this context, there is interest in using an electromagnetic induction coil (solenoid) as another simple sensor to measure the BCG and examining its possibility for BCG measurement. A small permanent magnet is attached tightly to the surface of an incubated egg, and then the egg with the magnet is placed in a solenoid. Preliminary model analysis is made to design a setup of the egg, magnet and solenoid coupling system. Then, simultaneous measurement with a laser displacement measuring system, developed previously, is made for chicken eggs, indicating that the solenoid detects the minute cardiogenic ballistic movements and that the BCG determined is a measure of the velocity of egg movements.

Animals↗
PubMed2005

Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition.

We report on very small fossil eggs from the Lower Cretaceous of Thailand, one of them containing a theropod embryo, which display a remarkable mosaic of characters. While the surficial ornamentation is typical of non-avian saurischian dinosaurs, the three-layered prismatic structure of the eggshell is currently known only in extant and fossil eggs associated with birds. These eggs, about the size of a goldfinch's, mirror at the reproductive level the retention of small body size that was paramount in the transition from non-avian theropods to birds. The egg-layer may have been a small feathered theropod similar to those recently found in China.

Animals↗
PubMed2006

In ovo exposure quail assay for risk assessment of endocrine disrupting chemicals.

Although there are in vivo assays using various organisms for the risk assessment of chemicals with endocrine disrupting properties, effective experimental methods for avian species are still under debate. We have developed an in ovo exposure assay using Japanese quail eggs, aimed at assessing disrupting effects on avian reproductive development and function. Hybrid eggs from Brazilian Brown male and White Egg female quails, which can be genetically sexed by their plumage color after hatching, were prepared, and test materials dissolved in olive oil were injected into the air-chamber on day 10 of incubation. After sexual maturation of hatched chicks, we observed egg production by females and the egg quality and male-typical reproductive behavior, and then examined reproductive system morphology and serum steroid concentrations in both sexes. Treatment with a synthetic estrogen, diethylstilbestrol (DES, 0.5-50 ng/g egg), dose-dependently reduced the eggshell thickness and strength of eggs. A few females treated with 5 ng/g DES per egg produced soft-shelled/ unmarked eggs, and all laying females treated with 50 ng/g egg produced eggs completely lacking shells. DES also induced shortening of the left oviduct and abnormal development of the right oviduct in a dose-dependent manner, while testis weight was reduced symmetrically. In addition, 2,2',4',6'-tetrachlorobiphenyl-4-ol (10-1,000 ng/g egg), which previously showed relatively high estrogenic activity in vitro, caused dose-dependent shortening of the left oviduct and reduction in testis weight. The methods for evaluating endocrine disrupting effects and preparing experimental birds proposed in the present study are expected to facilitate assays for avian reproductive toxicology.

Animals↗
PubMed2003

Composition of biomineral organic matrices with special emphasis on turbot (Psetta maxima) otolith and endolymph.

The soluble organic matrix (OM) of various biominerals (red coral skeleton, oyster shell, sea urchin test, turbot otolith, chicken eggshell) was extracted after demineralization with acetic acid. The protein content of the OM varies strongly from 0.02 to 1.6 microg/mg biomineral whereas proteoglycans present less variations (from 0.7 to 1.4 microg/mg biomineral). Electrophoresis of biominerals OM shows differences in their protein pattern although several bands are present in all matrices. OM of all biominerals shows carbonic anhydrase activity but no activity was detectable in the endolymph. OM of all biominerals also displays an anticalcifying activity. After separation of the OM extracts by chloroform-methanol, 80% of the anticalcifying activity was found in the methanol phase except in the urchin test. After OM precipitation with trichloracetic acid, 70% of the activities was found in the supernatants. Partial biochemical characterization suggests that the anticalcifying factor is a polyanionic and water-soluble molecule, which could be proteoglycans. The endolymph surrounding the otolith also displays an anticalcifying activity although its inhibitous activity was 50 times lower than that of the otolith OM. However, the anticalcifying activity of the endolymph is assumed by a proteic structure (80% activity precipitated with TCA treatment). Our results suggest that both carbonic anhydrase and anticalcifying activities are widespread and play a significant role in the regulation of biomineral formation. Results are discussed in relation to the calcification process that takes place at the fluid-mineral interface.

Animals↗
PubMed2005

Type I antifreeze proteins: possible origins from chorion and keratin genes in Atlantic snailfish.

Type I antifreeze proteins (AFPs) are alanine-rich alpha-helical polypeptides found in some species of right-eye flounders, sculpin, and snailfish. In this study, a shorthorn sculpin skin type I cDNA clone was used to probe an Atlantic snailfish liver cDNA library in order to locate expressed genes corresponding to snailfish plasma AFPs. Clones isolated from the cDNA library had sections with substantial amino acid and nucleotide sequence similarity to snailfish type I AFPs. However, further analysis revealed that the positives were actually three different liver-expressed proteins-two were eggshell proteins, while the third was a type II keratin. We propose that a shift in reading frame could produce alanine-rich candidate AFPs with possible antifreeze activity or ice crystal modification properties. Furthermore, it is plausible that one or more of the liver-expressed proteins represent the progenitors of snailfish type I AFPs.

Amino Acid Sequence↗
PubMed2002

Effects of Phos-Chek G75-F and Silv-Ex on developing northern bobwhite quail (Colinus virginianus).

Eggs of nesting birds situated in peripheral areas serving as fire breaks are at risk of being sprayed with fire control chemicals. Acute toxicity tests were conducted by immersing northern bobwhite quail eggs for 10 s in different water-based concentrations of Silv-Ex(R) (SE), a foam-suppressant chemical, and Phos-Chek(R) G75-F (PC), a fire retardant chemical, on day 4 or day 11 of incubation. An attempt was made to relate the treatment concentrations to the actual field application levels. Mortality appeared higher in most groups exposed on day 11 than on day 4, suggesting that on day 11 the extensive chorioallantoic vascular network permitted greater uptake of chemical. Only 24-60% of the embryos survived to hatch at exposure concentrations of 202, 269, and 454 g/L PC when treated on incubation day 11. At higher concentrations including 681956, and 1211 g/L PC, the compound did not completely dissolve in water and clumped on eggshells, resulting in greater hatching success. Exposures to SE at 100 g/L on incubation day 11 did not significantly affect hatching success of embryos but did significantly reduce the percent hematocrit in blood compared with controls. Incubation day 11 exposure to 202 and 1211 g/L PC led to a significant increase in plasma aspartate aminotransferase, and day 4 exposure to 1211 g/L PC resulted in a significant increase in alanine aminotransferase. In addition to elevated liver enzymes, these treatments resulted in a decrease in the number of hepatocyte profiles (1211 g/L PC at day 4 and day 11) and an increase in hepatocyte size (202 and 1211 g/L PC at day 11) in hatchlings. A combination of SE and PC was synergistic (202 g/L PC and 50 g/L SE) at day 11 of incubation with respect to decreased hatching success and reduced bone lengths. However, lower concentrations of SE (10 g/L or 30 g/L) combined with 202 g/L of PC appeared antagonistic. This may be due to SE, as a surfactant, altering the ability of PC to penetrate the egg. Our results show fewer adverse effects following exposure to SE than to PC; therefore application of SE may be less harmful to breeding bird populations.

Animals↗
PubMed2005

A risk assessment approach to DDE exposure based on the case of the eastern screech-owl (Megascops asio) in apple orchards of southern Quebec,Canada.

As part of a larger study assessing exposure of the Eastern screech-owl to pesticides in apple orchards from consumption of contaminated small-mammal prey, we evaluated the potential for owls in orchards of southern Quebec to be exposed to persistent contaminants with emphasis on DDE. Levels were highest in short-tailed shrews (0.94 to 26.29 microg/g wet wt). Based on a worst-case scenario, it is possible that consumption of small-mammal prey in orchards of the study area may result in exposure to DDE at a level associated with significant eggshell thinning; however, consumption of other prey, (e.g., robins) may represent a more important threat. Other organochlorines and persistent contaminants such as trace metals and PCBs, reported elsewhere, were found at negligible levels only. Based on an evaluation of the data used, we identify critical information required to enhance the proposed risk assessment.

Animals↗
PubMed2000

Organochlorine and metal contaminant exposure and effects in hatching black-crowned night herons (Nycticorax nycticorax) in Delaware Bay.

Pea Patch Island in Delaware Bay is the site of the largest heronry north of Florida. From 1989-93, the population of nine species of wading birds numbered approximately 12,000 pairs, but has recently declined to about 7,000 pairs. Because Delaware Bay is a major shipping channel and receives anthropogenic releases of toxic substances from agricultural, industrial, and municipal point and nonpoint sources, contaminant exposure and effects to the heronry have been an ongoing concern. In 1997, pipping (early hatching stage) black-crowned night herons (Nycticorax nycticorax) were collected from separate nests at Pea Patch Island and from a coastal reference site, Middle Island in Rehoboth Bay, Delaware. There was no evidence of malformations or hepatic histopathological lesions in embryos, and their body and liver weights did not differ between sites. Biomarkers of petroleum hydrocarbons, polyhalogenated contaminant, and metal exposure (cytochrome P450 induction and oxidative stress responses) did not differ (p > 0.05) between sites, although activities of benzyloxy-O-dealkylase and ethoxyresorufin-O-dealkylase were somewhat elevated in 3 of the 15 embryos collected from Pea Patch Island. Concentrations of 21 organochlorine pesticides and metabolites were relatively low at both sites, with p,p'-DDE values well below the threshold associated with eggshell thinning. Although total PCB concentration was modestly elevated (p < 0.05) in Pea Patch Island heron embryos, levels of arylhydrocarbon receptor-active PCB congeners, polychlorinated dibenzodioxins and dibenzofurans, and toxic equivalents were low and did not differ between sites. Concentrations of Cd and Mn in pipping embryos from Pea Patch Island were slightly greater (p < 0.05) than values observed in Middle Island embryos, but levels of these and the other metals and metalloids (e.g., Hg and Se) were below values associated with toxicity. In conclusion, it seems unlikely that chlorinated hydrocarbon and metal contaminant exposure constitutes a direct threat to the reproductive success of black-crowned night herons at Pea Patch Island. However, low-level exposure to these contaminants may constitute one of many stressors that in combination could adversely affect the stability of the wading bird population at this large heronry.

Animals↗
PubMed1999

Relative distribution of polychlorinated biphenyls among tissues of neonatal American alligators (Alligator mississippiensis).

Recent papers have investigated the utility of chemical analysis of the chorioallantoic membrane (CAM) as a nonlethal indicator of avian and reptilian exposure to persistent environmental contaminants. This study was undertaken to evaluate the chemical distribution among fat, CAM, and residual yolk tissues of live neonatal American alligators (Alligator mississippiensis) to investigate the potential utility of CAM use as a nonlethal indicator of exposure to polychlorinated biphenyls (PCBs). CAMs were collected from neonatal alligators at hatch, whereas yolk sacs and fat tissues were taken from each animal at euthanization (3 weeks posthatch). All collected tissue samples were separately Soxhlet extracted and analyzed by GC/ECD for PCBs. Log normalized, individual PCB congener concentrations in CAMs were significantly correlated with concentrations in fat (r(2) = 0.62) and yolk (r(2) = 0.56) tissues. Coefficients of determination from comparisons of homologue group concentrations varied from 0.13 to 0.90. Residue levels in neonatal oviparous organism tissues may be qualitatively assessed through chemical analyses of CAM tissues removed from discarded eggshells.

Allantois↗
PubMed2001

Extraskeletal osteosarcoma arising in myositis ossificans.

A 53-year-old woman had extraskeletal osteosarcoma that developed from a soft tissue bony mass present on the volar aspect of the left wrist for 4 years. Initially, the bony mass was soft and movable, but during the first year it became hard and fixed. The patient had no history of trauma. Because the lesion did not grow or cause any symptoms, the patient did not come to the hospital until 4 years after she first noticed the lesion. Radiologically, the bony mass had features characteristic of mature myositis ossificans, showing "eggshell" ossification. A nonmineralized soft tissue mass occurred between the surface of the radius and the bony shell. Histologically, a high-grade osteosarcoma was present between the surface of the radius and the well-differentiated bone tissue, which included fatty and hematopoietic marrow. All the findings indicated that our patient had an extremely rare case of malignant transformation of myositis ossificans.

Female↗