Ozone-induced responses in Arabidopsis thaliana: the role of salicylic acid in the accumulation of defense-related transcripts and induced resistance.

Exposure of Arabidopsis thaliana to ozone results in the expression of a number of defense-related genes that are also induced during a hypersensitive response. A potential common link between the activation of defense gene expression during a hypersensitive response and by ozone treatment is the production of active oxygen species and the accumulation of hydrogen peroxide. Here we report that salicylic acid accumulation, which can be induced by hydrogen peroxide and is required for the expression of both a hypersensitive response and systemic acquired resistance, is also required for the induction of some, but not all, ozone-induced mRNAs examined. In addition, we show that ozone exposure triggers induced resistance of A. thaliana to infection with virulent phytopathogenic Pseudomonas syringae strains. Infection of transgenic plants expressing salicylate hydroxylase, which prevents the accumulation of salicylic acid, or npr1 mutant plants, which are defective in the expression of systemic acquired resistance at a step downstream of salicylic acid, demonstrated that the signaling pathway activated during ozone-induced resistance overlaps with the systemic acquired resistance activation pathway and is salicylic acid dependent. Interestingly, plants expressing salicylate hydroxylase exhibited increased sensitivity to ozone exposure. These results demonstrate that ozone activates at least two distinct signaling pathways, including a salicylic acid dependent pathway previously shown to be associated with the activation of pathogen defense reactions, and that this latter pathway also induces a protective response to ozone.

p53 deficiency does not affect the accumulation of point mutations in a transgene target.

DNA repair is required by organisms to prevent the accumulation of mutations and to maintain the integrity of genetic information. Mammalian cells that have been treated with agents that damage DNA have an increase in p53 levels, a p53-dependent arrest at G1 in the cell cycle, and a p53-dependent apoptotic response. It has been hypothesized that this block in cell cycle progression is necessary to allow time for DNA repair or to direct the damaged cell to an apoptotic pathway. This hypothesis predicts that p53-deficient cells would have an abnormal apoptotic response and exhibit a "mutator" phenotype. Using a sensitive assay for the accumulation of point mutations, small deletions, and insertions, we have directly tested whether p53-deficient cells exhibit an increased frequency of mutation before and after exposure to DNA-damaging agents. We report that wild-type and p53-deficient fibroblasts, thymocytes, and tumor tissue have indistinguishable rates of point mutation accumulation in a transgenic lacI target gene. These results suggest that the role of p53 in G1 checkpoint control and tumor suppression does not affect the accumulation of point mutations.

Accumulation of plasma cells in atherosclerotic lesions of Watanabe heritable hyperlipidemic rabbits.

By screening a cDNA library constructed from aortic total RNA derived from Watanabe heritable hyperlipidemic (WHHL) rabbits by differential hybridization, we have obtained a cDNA encoding the kappa light chain of immunoglobulin. Northern blot analysis of total RNA prepared from aortas of WHHL and normal rabbits of various ages revealed that this light-chain mRNA accumulates gradually with age in aortas in WHHL rabbits. Northern blotting and in situ hybridization with an antisense oligonucleotide specific to rabbit immunoglobulin gamma heavy-chain mRNA also detected accumulation of this heavy-chain mRNA in advanced lesions of WHHL rabbit aortas. Moreover, immunohistochemical and electron microscopic analyses demonstrated the presence of plasma cells in the atherosclerotic lesions.

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells.

The accumulation of phenylalanine-derived phenolic compounds is a well-known element of a plant's defense in response to pathogen attack. Phenylalanine, as well as the other two aromatic amino acids, tyrosine and tryptophan, is synthesized by way of the shikimate pathway. The first seven steps of the shikimate pathway (the prechorismate pathway) are common for the biosynthesis of all three aromatic amino acids. We have studied transcript levels of six genes--i.e., two 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase genes, one shikimate kinase gene, one 5-enolpyruvylshikimate 3-phosphate synthase gene, and two chorismate synthase genes--corresponding to four steps of the prechorismate pathway, in cultured tomato cells exposed to fungal elicitors. The abundance of transcripts specific for some of these genes increased 10- to 20-fold within 6 h after elicitor treatment, as did the abundance of phenylalanine ammonialyase-specific transcripts and the synthesis of ethylene. Interestingly, transcript accumulation occurred more rapidly for shikimate kinase than for the enzymes preceding or following it in the prechorismate pathway. Neither the inhibition of ethylene biosynthesis by aminoethoxyvinylglycine nor inhibition of phenylalanine ammonia-lyase (EC 4.3.1.5) activity by 2-aminoindan-2-phosphonic acid affected the time course or extent of transcript accumulation. Thus, the increased demand for phenylalanine in the phenylpropanoid pathway required after elicitor treatment appears to be met by increased de novo synthesis of its biosynthetic enzymes.

Is socioeconomic position early in life associated with physical activity during adulthood following the accumulation of risk model with additive effects?

L'activité physique améliore la santé, mais seulement 4.8% des Canadiens atteignent le niveau recommandé. La position socio-économique est un des déterminants de l'activité physique les plus importants. Elle est associée à l’activité physique de manière transversale à l’adolescence et à l’âge adulte. Cette thèse a tenté de déterminer s'il y a une association à long terme entre la position socio-économique au début du parcours de vie et l’activité physique à l’âge adulte. S'il y en avait une, un deuxième objectif était de déterminer quel modèle théorique en épidémiologie des parcours de vie décrivait le mieux sa forme. Cette thèse comprend trois articles: une recension systématique et deux recherches originales. Dans la recension systématique, des recherches ont été faites dans Medline et EMBASE pour trouver les études ayant mesuré la position socio-économique avant l'âge de 18 ans et l'activité physique à ≥18 ans. Dans les deux recherches originales, la modélisation par équations structurelles a été utilisée pour comparer trois modèles alternatifs en épidémiologie des parcours de vie: le modèle d’accumulation de risque avec effets additifs, le modèle d’accumulation de risque avec effet déclenché et le modèle de période critique. Ces modèles ont été comparés dans deux cohortes prospectives représentatives à l'échelle nationale: la 1970 British birth cohort (n=16,571; première recherche) et l’Enquête longitudinale nationale sur les enfants et les jeunes (n=16,903; deuxième recherche). Dans la recension systématique, 10 619 articles ont été passés en revue par deux chercheurs indépendants et 42 ont été retenus. Pour le résultat «activité physique» (tous types et mesures confondus), une association significative avec la position socio-économique durant l’enfance fut trouvée dans 26/42 études (61,9%). Quand seulement l’activité physique durant les loisirs a été considérée, une association significative fut trouvée dans 21/31 études (67,7%). Dans un sous-échantillon de 21 études ayant une méthodologie plus forte, les proportions d’études ayant trouvé une association furent plus hautes : 15/21 (71,4%) pour tous les types et toutes les mesures d’activité physique et 12/15 (80%) pour l’activité physique de loisir seulement. Dans notre première recherche originale sur les données de la British birth cohort, pour la classe sociale, nous avons trouvé que le modèle d’accumulation de risque avec effets additifs s’est ajusté le mieux chez les hommes et les femmes pour l’activité physique de loisir, au travail et durant les transports. Dans notre deuxième recherche originale sur les données canadiennes sur l'activité physique de loisir, nous avons trouvé que chez les hommes, le modèle de période critique s’est ajusté le mieux aux données pour le niveau d’éducation et le revenu, alors que chez les femmes, le modèle d’accumulation de risque avec effets additifs s’est ajusté le mieux pour le revenu, tandis que le niveau d’éducation ne s’est ajusté à aucun des modèles testés. En conclusion, notre recension systématique indique que la position socio-économique au début du parcours de vie est associée à la pratique d'activité physique à l'âge adulte. Les résultats de nos deux recherches originales suggèrent un patron d’associations le mieux représenté par le modèle d’accumulation de risque avec effets additifs.

Accumulation of particulate organic carbon at the Eurasian continental margin during late Quaternary times

Data on the amount and composition of organic carbon were determined in sediment cores from the Kara and Laptev Sea continental margin, representing oxygen isotope stages 1-6. The characterization of organic matter is based on hydrogen index (HI) values, n-alkanes and maceral composition, indicating the predominance of terrigenous organic matter through space and time. The variations in the amount and composition of organic carbon are mainly influenced by changes in fluvial sediment supply, Atlantic water inflow, and continental ice sheets. During oxygen isotope stage (OIS) 6, high organic carbon contents in sediments from the Laptev Sea and western East Siberian Sea continental margin were probably caused by the increased glacial erosion and further transport in the eastward-flowing boundary current along the continental margin. During OIS 5 and early OIS 3, some increased amounts of marine organic matter were preserved in sediments east of the Lomonosov Ridge, suggesting an influence of nutrient-rich Pacific waters. During OIS 2, terrigenous organic carbon supply was increased along the Barents and western Kara Sea continental margin caused by extended continental ice sheets in the Barents Sea (Svalbard to Franz Josef Land) area and increased glacial erosion. Along the Laptev Sea continental margin, on the other hand, the supply of terrigenous (organic) matter was significantly reduced due to the lack of major ice sheets and reduced river discharge. Towards the Holocene, the amount of total organic carbon (TOC) increased along the Kara and Laptev Sea continental margin, reaching average values of up to 0.5 g C/cm**2/ky. Between about 8 and 10 ka (9 and 11 Cal ka), i.e., during times when the inner shallow Kara and Laptev seas became largely flooded for the first time after the Last Glacial Maximum, maximum supply of terrigenous organic carbon occurred, which is related to an increase in coastal erosion and Siberian river discharge. During the last 8000 years, the increased amount of marine organic carbon preserved in the sediments from the Kara and Laptev Sea continental margin is interpreted as a result of the intensification of Atlantic water inflow along the Eurasian continental margin.

Seawater carbonate chemistry and accumulation of radiotracers in squid, Loligo vulgaris during experiments, 2011

The anthropogenic release of carbon dioxide (CO2) into the atmosphere leads to an increase in the CO2 partial pressure (pCO2) in the ocean, which may reach 950 ?atm by the end of the 21st century. The resulting hypercapnia (high pCO2) and decreasing pH ("ocean acidification") are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO2 (380, 850 and 1500 ?atm corresponding to pHT of 8.1, 7.85 and 7.60) on the accumulation of dissolved 110mAg, 109Cd, 57Co, 203Hg, 54Mn and 65Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for 110mAg, 203Hg and 65Zn were affected by the pCO2 treatments. In the embryo, increasing seawater pCO2 enhanced the uptake of both 110mAg and 65Zn while 203Hg showed a minimum concentration factor (CF) at the intermediate pCO2. 65Zn incorporation in statoliths also increased with increasing pCO2. Conversely, uptake of 109Cd and 54Mn in the embryo decreased as a function of increasing pCO2. Only the accumulation of 57Co in embryos was not affected by increasing pCO2. In paralarvae, the CF of 110mAg increased with increasing pCO2, whereas the 57Co CF was reduced at the highest pCO2 and 203Hg showed a maximal uptake rate at the intermediate pCO2. 54Mn and 65Zn accumulation in paralarvae were not significantly modified by hypercapnic conditions. Our results suggest a combined effect of pH on the adsorption and protective properties of the eggshell and of hypercapnia on the metabolism of embryo and paralarvae, both causing changes to the accumulation of metals in the tissues of L. vulgaris.

The traction generating potential of snow tires vs. regular tread tires on ice, snow, wet, and dry surfaces. Technical report.

Mode of access: Internet.

Federal-state-private cooperative snow surveys, 1953-1957; summary of snow survey measurements for Idaho [portions of British Columbia, Montana, Wyoming, and Nevada within the Columbia Basin]

Mode of access: Internet.

Summary of snow survey measurements, Wyoming : and pertinent measurements in Colorado, Montana and South Dakota : 1919-1982 /

Chiefly tables.

List and location of snow courses and snotel sites /

Mode of access: Internet.

Summary of snow survey measurements for Oregon.

"This summary supersedes all previous Oregon summaries including the last one issued June 1, 1963."

Principles of snow surveying as applied to forecasting stream flow.

Mode of access: Internet.