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Migratory seabirds face threats from climate change and a variety of anthropogenic disturbances. Although most seabird research has focused on the ecology of individuals at the colony, technological advances now allow researchers to track seabird movements at sea and during migration. We combined telemetry data on Onychoprion fuscatus (sooty terns) with a long-term capture-mark-recapture dataset from the Dry Tortugas National Park to map the movements at sea for this species, calculate estimates of mortality, and investigate the impact of hurricanes on a migratory seabird. Included in the latter analysis is information on the locations of recovered bands from deceased individuals wrecked by tropical storms. We present the first known map of sooty tern migration in the Atlantic Ocean. Our results indicate that the birds had minor overlaps with areas affected by the major 2010 oil spill and a major shrimp fishery. Indices of hurricane strength and occurrence are positively correlated with annual mortality and indices of numbers of wrecked birds. As climate change may lead to an increase in severity and frequency of major hurricanes, this may pose a long-term problem for this colony.

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Many sea turtle populations are below 10% of their pre-Columbian numbers [1-4]. Though historic and systematic over-exploitation is the principal cause of these declines, sea turtles face similar threats today. Adults and juveniles are actively hunted and commercial fisheries catch them incidentally. Nesting suffers from beach development, egg poaching and the poaching of nesting females. Accompanying these familiar hazards is the largely unknown consequences of recent climate change. Here we report monitoring surveys from the Dry Tortugas National Park (DTNP, 24.64N 82.86W), Florida, and show that hurricanes and other storm events are an additional and increasing threat to loggerhead turtle (Caretta caretta) and green sea turtle (Chelonia mydas) nesting. Both species are listed by the US Endangered Species Act and the IUCN considers them 'endangered'.

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Apolipoprotein E (apoE4) and head trauma are important genetic and environmental risk factors for Alzheimer's disease. Furthermore, apoE4 increases both the acute and chronic consequences of head trauma. The latter are associated with the deposition of amyloid-beta, which is particularly elevated in apoE4 subjects. The short-term effects of head injury are associated with transiently increased metabolism of amyloid precursor protein (APP) and its secreted fragment, APPs. In the present study, we examined the possibility that the acute, short-term pathological effects of apoE4 following head trauma and the corresponding neuroprotective effects of apoE3 are related to isoform-specific effects of apoE on APP metabolism. Accordingly, male transgenic mice expressing human apoE3 or apoE4 on a null mouse apoE background and apoE-deficient and control mice were subjected to closed head injury (CHI). The resulting effects on brain APP, and on its secreted products, APPs and secreted product of the alpha-cleavage of APP (APPsalpha) were then determined 24 h following injury. Immunoblotting revealed no significant differences between the basal APP, APPs and APPsalpha levels of the hippocampus or the cortex of the control and the apoE3 and ApoE4 transgenic mice. The apoE-deficient mice also had similar cortical basal levels of APP and its metabolites, whereas their corresponding basal hippocampal APP and APPs levels were lower than those of the other groups. CHI lowered the hipppocampal APPs and APPsalpha levels of the apoE4 transgenic mice, whereas those of the apoE3 transgenic mice and of the control and apoE-deficient mice were not affected by this insult. In contrast, CHI raised the cortical APP and APPs levels of the apoE3 transgenic mice but had no significant effect on those of the other mice groups. These animal model findings suggest that the acute, short-term pathological effects of apoE4 following CHI and the corresponding neuroprotective effects of apoE3 may be mediated by their opposing effects on the expression and cleavage of cortical and hippocampal APP. Similar isoform-specific interactions between apoE and APP may play a role in the acute, short-term effects of head trauma in humans.

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Genetic studies suggest that the neuropathology and etiology of Alzheimer's disease (AD) are associated with several genotypes including mutations in the amyloid precursor protein (APP) gene and the allele E4 of apolipoprotein E (apoE). The present study investigated the possibility that cross talk interactions exist between APP and apoE and the extent to which they are affected by the apoE genotype. This was pursued by cell culture and immunoblot experiments utilizing neuroblastoma N2a cells in which the effects of distinct apoE isoforms on the levels of intracellular APP and of secreted APPs were determined. This revealed that treatment of the cells with apoE4, the AD risk factor, resulted in a marked increase in the levels of secreted APPs. This effect was dose dependent (ED50 approximately/= 2.5 microg/ml) and isoform specific in that apoE3 had virtually no effect on the secretion of APPs.

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Apolipoprotein E (ApoE) is the major brain lipoprotein and plays an important role in lipid transport. ApoE-deficient mice whose apoE gene has been knocked out have distinct cognitive and neurochemical deficits, and their recovery from brain injury is impaired. In the present study we examined the possibility that the neuronal derangements of apoE-deficient mice are related to impairments in their phospholipid metabolism. This was performed by comparison of the phospholipid, fatty acid, and cholesterol compositions of distinct membranal brain fractions of apoE-deficient and control mice. Analysis of the microsomal membrane fraction P(3) revealed that, in apoE-deficient mice, these membranes contain significantly lower levels of phosphatidylcholine (PC) than those of control mice. This effect was specific to PC and thus resulted in a twofold decrease of the PC to phosphatidylethanolamine (PE) ratio in apoE-deficient mice compared to the corresponding control ratio. In contrast, the cholesterol levels of the microsomal membranes of the two mice were similar, and the fatty acid composition of their PC was unchanged. There were, however, changes in the fatty acid composition of PE and phosphatidylserine (PS), which resulted in a lower ratio of polyunsaturated to saturated fatty acids in PE and in a higher ratio in apoE-deficient mice compared to the corresponding control values. These effects were specific to the microsomal fraction P(3) and were not observed with the brain subcellular membrane fraction P(2), which is composed mainly of plasma and mitochondrial membranes and whose phospholipid, fatty acid, and cholesterol levels were similar in apoE-deficient and control mice. These findings show that apoE deficiency results in specific and intracellular compartment-dependent changes in phospholipid metabolism, which may play an important role in mediating the neuronal effects of apoE.

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Previous studies utilizing apolipoprotein E (apoE)-deficient mice revealed distinct decreases in the levels of cholinergic synaptic markers of projecting basal forebrain cholinergic neurons and no such alterations in other brain cholinergic systems. In order to investigate the mechanisms underlying these neuron-specific cholinergic effects, primary neuronal cultures from apoE-deficient and control mice were prepared and characterized. These include basal forebrain cultures, which are enriched in projecting cholinergic neurons, and cortical cultures, which contain cholinergic interneurons. The levels of cholinergic nerve terminals in these cultures were assessed by ligand binding measurements of the levels of the vesicular acetylcholine transporter (VAChT). This revealed that basal forebrain cultures of apoE-deficient mice contain markedly lower VAChT levels (approximately 50%) than do control cultures, but that VAChT levels of the corresponding cortical cultures of the apoE-deficient and control mice were the same. Time course studies revealed that VAChT levels of the basal forebrain cultures increased with culture age, but that the relative reduction in VAChT levels of the apoE-deficient cholinergic neurons was unaltered and was the same for freshly prepared and for 96 h old cultures. These in vitro observations are in accordance with the in vivo findings and suggest that projecting basal forebrain cholinergic neurons, but not cholinergic interneurons, are markedly dependent on apoE and that similar mechanisms mediate the in vivo and in vitro effects of apoE deficiency on cholinergic function.

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Alzheimer's disease (AD) is associated with serum antibodies directed specifically against phosphorylated epitopes highly enriched in the heavy neurofilament protein NF-H of cholinergic neurons. Prolonged immunization of rats with these molecules but not with other NF-H isoforms results in cognitive impairments. This animal model, termed experimental autoimmune dementia (EAD), supports a role for such antibodies in neurodegeneration in AD. In the present study we investigated the cellular and immunological mechanisms underlying the cognitive defects in EAD. Immunohistochemical studies revealed that IgG accumulate in the septum, hippocampus and in the entorhinal cortex of the EAD rats. This is accompanied by a marked reduction in the density of septal cholinergic neurons. An inverse correlation was observed between the level of IgG in the septum of individual EAD rats and the density of their septal cholinergic neurons. Time course studies revealed that the decrease in the density of cholinergic neurons in the septum of EAD rats and the accumulation of IgG in this brain area have the same time course and are both significant by three to four months following the initiation of immunization with cholinergic NF-H. The cognitive deficits of the EAD rats evolve more slowly and are pronounced only after six months following the initation of immunization. In vitro studies revealed that anti NF-H IgG bind to the outer surface of neurons in tissue cultures of rat forebrain and can affect neuronal viability. These AD and in vitro findings provide model systems for studying the mechanisms underlying the neuropathological effects of specific anti NF-H antibodies.

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The release of acetylcholine from Torpedo electric organ slices following their electrical stimulation was modulated by morphine, by the muscarinic antagonist atropine, and by the nicotinic antagonist tubocurarine. Addition of either atropine or tubocurarine in the presence of the acetylcholinesterase inhibitor phospholine iodide enhanced acetylcholine release. The effects of the two antagonists were additive, a result suggesting that the secreted acetylcholine regulates its own release by activating both muscarinic and nicotinic cholinergic receptors and that these receptors inhibit acetylcholine release by different mechanisms. The effects of opiates on acetylcholine release were examined under conditions in which the cholinergic modulation of release is blocked, i.e., in the presence of atropine and tubocurarine. These experiments revealed that electrically evoked release of acetylcholine is blocked by the opiate agonists morphine and levorphanol. However, the inhibitory effect of morphine on acetylcholine release was not reversed by the opioid antagonist naloxone. Furthermore, dextrorphan, the nonopioid stereoisomer of levorphanol, had the same inhibitory effect as its opioid counterpart. These findings suggest that the effects of opiates on electrically evoked release of acetylcholine are not mediated by opioid receptors. The possible mechanisms underlying these nonopioid effects of morphine and levorphanol are discussed.

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The opioid peptide dynorphin A(1-8) (1 micron) increased acetylcholine release from the Torpedo electric organ by approximately twofold. This effect was reversed by the opiate antagonist naloxone. The effect of Dyn A(1-8) on acetylcholine release was found to vary in magnitude with the seasons of the year, with maximal enhancement being observed in the summer and none in winter. Dynorphin B, methionine-enkephalin and leucine-enkephalin also increased acetylcholine release and showed similar seasonal variations. These findings suggest that acetylcholine release from Torpedo electromotor neurons is regulated by opiate receptors. The physiological significance of these observations is discussed in view of the previous findings that the Torpedo neurons contain an endogenous enkephalin-like peptide.

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Immunoblotting was used for simultaneous measurements of rates of de novo synthesis and steady-state levels of a model protein-cytochrome P450r. This is the major phenobarbital-inducible P450 form in cultured chick-embryo hepatocytes (L. Oron, and S. Bar-Nun, 1984) Biochem. Biophys. Res. Commun. 125, 1096-1102). Cultured hepatocytes were metabolically labeled with [35S]methionine, and cellular proteins were resolved by gel electrophoresis and then quantitatively electroblotted onto nitrocellulose. The blot was directly exposed to autoradiography and the rates of de novo synthesis were estimated from the 35S label of P450r. The same blot was then incubated with specific anti-P450r antibodies, followed by 125I-labeled secondary antibodies, and the blot was reexposed to autoradiography through white paper. The paper masked the 35S-labeled proteins and the steady-state levels were estimated from the 125I-immunodecorated P450r. By this simple method, "true" inducers of cytochrome P450r, such as phenobarbital, can be defined, whereas "false" inducers, which primarily affect the degradation of P450r, can be detected.

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The induction of cytochrome P-450 in cultured chick embryo hepatocytes was studied using two structurally unrelated compounds, 2-allyl-2-isopropylacetamide and phenobarbital. Pulse-labeling of these cells showed enhanced de novo synthesis of cytochrome P-450. The cytochrome induced by 2-allyl-2-isopropylacetamide, as well as the one induced by phenobarbital, reacted immunologically with antibodies raised against the major hepatic phenobarbital-induced isozyme. Additional form of cytochrome P-450 is induced exclusively by phenobarbital. These results clearly demonstrate that these two drugs induce at least one form of cytochrome P-450 in common.

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The induction of cytochrome P-450 by phenobarbital was studied in primary cultures of chick embryo hepatocytes. The rate of the de novo synthesis of the induced form of cytochrome P-450 was measured directly and specifically, using form-specific anti-cytochrome antibodies that quantitatively immunoprecipitated this form from the radiolabeled hepatocytes. Additionally, the steady-state levels of the cytochrome were estimated spectrophotometrically and electrophoretically. In the presence of phenobarbital the synthesis of cytochrome P-450PB by cultured hepatocytes was markedly accelerated. Furthermore, the same cytochrome P-450PB form was induced by phenobarbital in vivo in chicken liver and in the cultured chick embryo hepatocytes. Their identity was judged from immunological and electrophoretic properties of these induced cytochromes. Immunological cross-reactivity was also detected between the cytochrome P-450PB forms from chick embryo hepatocytes and from adult rat liver. The immunological cross-reactivity observed between the phenobarbital-induced cytochrome P-450 forms from different species was not observed between the different cytochrome forms with the same liver (Thomas, P.E., Reik, L.M., Ryan, D.E. and Levin, W. (1981) J. Biol. Chem. 256, 1044-1052). Implications as to the evolutionary origin of the different cytochrome forms are discussed.

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A polycytidylate-dependent RNA polymerase of encephalomyocarditis virus was isolated from infected BHK 21 cells. The enzyme was associated with a smooth-membrane fraction, from which it was extracted by a mixture of sodium dodecyl sulfate, Triton X-100, and dithiothreitol, and further purified by chromatography on a Dowex-1 column and by glycerol gradient sedimentation. Analysis of a 6S glycerol gradient peak of RNA polymerase activity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of five polypeptides, of molecular weights 72,000, 65,000, 57,000, 45,000, and 35,000. The molecular weights of four of the polypeptides (72,000, 65,000, 45,000, and 35,000) are almost identical to the reported molecular weights of the four subunits of Qbeta replicase.

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