215 research outputs found
Expression of cytochrome c oxidase during growth and development of Dictyostelium
No full textIn the slime mold Dictyostelium discoideum, the subunit composition of cytochrome c oxidase depends on oxygen that inversely regulates the concentrations of two alternative isoforms of the smallest enzyme subunit (Schiavo, G., and Bisson, R. (1989) J. Biol. Chem. 264, 7129-7134). In order to investigate their role in the Dictyostelium life cycle, the expression of the oxidase subunits was monitored during cell growth and development. The results obtained demonstrate that exponentially growing amoebae respond rapidly and precisely to hypoxia by switching the expression of the two isoforms and also by increasing the levels of the mRNAs of the different oxidase subunits in a highly coordinated process. During normal development the "hypoxic" subunit is not synthesized, but its level of expression appears to parallel the sensitivity to oxygen of development, rising steeply below 10% oxygen when the differentiation program is virtually blocked. Under these conditions, the expression of the alternative subunit isoform is essentially oxygen-insensitive. These findings suggest that the physiological relevance of the subunit switching concerns primarily the vegetative phase of growth, possibly as part of a more general mechanism evolved in order to evade conditions that do not allow development. Taken together, the data obtained offer an intriguing example of the fine control exerted on the expression of a key respiratory enzyme in a strictly aerobic organism
Different polypeptides of bovine heart cytochrome c oxidase are in contact with cytochrome c
No full textAbstractTwo water-soluble carbodiimides, differing in molecular dimensions, have been used to characterize the cytochrome c binding site of bovine heart cytochrome c oxidase. Several polypeptide components of the enzyme contain acidic residues which are modified by these reagents. Carboxyl groups present in subunit II, VII and polypeptide c, are protected from modification when cytochrome c, equimolar to oxidase, is added and they can cross-link to the substrate once activated by the carbodiimide. Comparison of the modification patterns suggest that the most reactive residues are located on subunit II and VII, the former being also more exposed. The data obtained indicate that eventhough subunit II plays the major role in binding cytochrome c, at least two other lower Mr polypeptides contribute to the cytochrome c binding domain
Petrology of the post-40 ka products in the Vulcano-Lipari volcanic complex (Aeolian Islands, Italy): an example of volcanism controlled by tectonics
No full textOver the last 42 ka, volcanic activity at Lipari Island (Aeolian Arc, Italy) produced lava domes, flows and pyroclastic deposits with rhyolitic composition, showing in many cases evidence of magma mixing such as latitic enclaves and banding. In this same period, on nearby Vulcano Island, similar rhyolitic lava domes, pyroclastic products and lava flows, ranging in composition from shoshonite to rhyolite, were erupted. As a whole, the post-42 ka products of Lipari and Vulcano show geochemical variations with time, which are well correlated between the two islands and may correspond to a modification of the primary magmas. The rhyolitic products are similar to each other in their major elements composition, but differ in their trace element abundances (e.g. La ranging from 40 to 78 ppm for SiO2 close to 75 wt%). Their isotopic composition is variable, too. The 87Sr/86Sr (0.704723–0.705992) and 143Nd/144Nd (0.512575–0.512526) ranges partially overlap those of the more mafic products (latites), having 87Sr/86Sr from 0.7044 to 0.7047 and 143Nd/144Nd from 0.512672 to 0.512615. 206Pb/204Pb is 19.390–19.450 in latites and 19.350–19.380 in rhyolites. Crystal fractionation and crustal assimilation processes of andesitic to latitic melts, showing an increasing content in incompatible elements in time, may explain the genesis of the different rhyolitic magmas. The rocks of the local crustal basement assimilated may correspond to lithotypes present in the Calabrian Arc. Mixing and mingling processes between latitic and rhyolitic magmas that are not genetically related occur during most of the eruptions. The alignment of vents related to the volcanic activity of the last 40 ka corresponds to the NNW–SSE Tindari–Letojanni strike-slip fault and to the correlated N–S extensional fault system. The mafic magmas erupted along these different directions display evidence of an evolution at different PH2O conditions. This suggests that the Tindari–Letojanni fault played a relevant role in the ascent, storage and diversification of magmas during the recent volcanic activity
RAPID TERRAIN-BASED MAPPING OF SOME VOLCANICLASTIC FLOW HAZARD USING GIS-BASED AUTOMATED METHODS: A CASE STUDY FROM SOUTHERN CAMPANIA, ITALY
No full textPetrololgy of volcanic products younger than 40 ka on the Lipari-Vulcano complex (Aeolian Islands, Italy): an example of volcanism controlled by tectonics
No full textRapid terrain-based mapping of some volcaniclastic flow hazard using Gis-based automated methods: a case study from southern Campania,
No full textAbstract Destructive volcaniclastic flows are among the most recurrent and dangerous natural phenomena in volcanic areas. They can originate not only during or shortly after an eruption (syn-eruptive) but also during a period of volcanic quiescence (inter-eruptive), when heavy and/or persistent rains remobilize loose pyroclastic deposits. The area in Italy most prone to such flows is that of the Apennine Mountains bordering the southern Campania Plain. These steep slopes are covered by pyroclastic material of variable thickness (a few cm to several m) derived from the explosive activity of the Somma- Vesuvius and Campi Flegrei volcanoes a few tens of kilometers to the west. The largest and most recent devastating event occurred on May 5, 1998, causing the death of more than 150 people and considerable damage to villages at the foot of the Apennine Mountains. This tragic event was only the most recent of a number of volcaniclastic flows affecting the area in both historical and prehistoric times. Historical accounts report that more than 500 events have occurred in the last five centuries and that more than half of these occurred in the last 100 years, causing hundreds of deaths. In order to improve volcaniclastic flow hazard zonation and risk mitigation in the study area, we produced a zonation map that identifies the drainage basins potentially prone to disruption. This map was obtained by combining morphological characteristics (concavity and basin shape factor) and the mean slope distribution of drainage basins derived from a digital elevation model with a 10-m resolution. These parameters allowed for the classification of 1,069 drainage basins, which have been grouped into four different classes of proneness to disruption: low, moderate,high and very high. The map compiled in a GIS environment, as well as the linked database, can be rapidly queried
Yenan, China, T. A. Bisson Speaking at Meeting
No full textAn image scanned from a black and white photograph with a handwritten caption on the back that reads, Yenan Meeting (3) author speaking. One in a series of photographs documenting a trip taken by Thomas Arthur Bisson and related to his subsequent publication, Yenan in June 1937: Talks with the Communist Leaders.https://digitalcommons.library.umaine.edu/spec_photos/3462/thumbnail.jp
Free Movement in the EU: Harmonisation of Mobile Citizens’ Social Rights
No full textThe author focuses on the current stagnation in negotiating process on the further improvement of supranational regulation on coordination of social security systems in the European Union. The article examines the basic principles of the free movement of workers in the EU and notes that the 2004/2007 EU enlargement has had a significant impact on the scale and direction of labour mobility within the Community. The analysis of the main indicators and characteristics of workers' mobility reveals the existing disparities between the Member States. The author points out that the divergence of national social security regimes, as well as diverging interests of individual EU Member States, such as protecting the rights of their own mobile citizens, or combating “social dumping”, play a key role in hindering the harmonization of social security rules in the context of freedom of movement. The concept of “failing forward” used for the study allowed to comprehend how social integration can be promoted when challenged by contradictions. The need to comply with the rules of the common internal market, on the one hand, and the interests of individual EU member states and their citizens, on the other, in a situation where the current legislation does not meet the challenges of the time, and the development of new legislation is constantly blocked, leads the EU institutions to intensify intergovernmental cooperation and resort to complementary mechanisms. The author concludes that the use of nonbinding regulatory instruments such as electronic data exchange serves as an intermediate link in the process of deepening integration in the area and may become an impetus for restarting negotiations and help finalise the text of the new legislation
Docteur! Comédie en un acte.
No full text"Représentée pour la première fois, à Paris, sur le théâtre du Gymnase, le 24 août 1900."At head of title: Alexandre Bisson & Georges Thurner.Mode of access: Internet
Comestible Edible : L'aliment comme matériau = Edible : Food as Material
No full text"Diane Bisson presents her first book, a colourful and textured reflection on cooking and our dietary habits. In face of the proliferation of disposable containers and over-packaging, the author invites us to take up the challenge of transforming food into genuine design material. Flatware made of quinoa, plates for desert, biscuit drinking straws, 100% edible lunches: such are the author's objectives. Edible, Food as material presents the results of this playful yet scientific journey with a collection of magnificent photographs and over thirty food samples designed and developed by the author. Her research rests on a vision resolutely linked with sustainable development as it explores the concept of the edible plate as both cultural model and viable material for the reduction of waste. Edible, Food as material fuses art with science to present the possible scope of a future series of edible plates and containers." - Publisher's website
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