Production of cyanophycin in Rhizopus oryzae through the expression of a cyanophycin synthetase encoding gene

Cyanophycin or cyanophycin granule peptide is a protein that results from non-ribosomal protein synthesis in microorganisms such as cyanobacteria. The amino acids in cyanophycin can be used as a feedstock in the production of a wide range of chemicals such as acrylonitrile, polyacrylic acid, 1,4-butanediamine, and urea. In this study, an auxotrophic mutant (Rhizopus oryzae M16) of the filamentous fungus R. oryzae 99-880 was selected to express cyanophycin synthetase encoding genes. These genes originated from Synechocystis sp. strain PCC6803, Anabaena sp. strain PCC7120, and a codon optimized version of latter gene. The genes were under control of the pyruvate decarboxylase promoter and terminator elements of R. oryzae. Transformants were generated by the biolistic transformation method. In only two transformants both expressing the cyanophycin synthetase encoding gene from Synechocystis sp. strain PCC6803 was a specific enzyme activity detected of 1.5 mU/mg protein. In one of these transformants was both water-soluble and insoluble cyanophycin detected. The water-soluble fraction formed the major fraction and accounted for 0.5% of the dry weight. The water-insoluble CGP was produced in trace amounts. The amino acid composition of the water-soluble form was determined and constitutes of equimolar amounts of arginine and aspartic acid

Metabolic engineering of Rhizopus oryzae for the production of platform chemicals

Rhizopus oryzae is a filamentous fungus belonging to the Zygomycetes. It is among others known for its ability to produce the sustainable platform chemicals l-(+)-lactic acid, fumaric acid, and ethanol. During glycolysis, all fermentable carbon sources are metabolized to pyruvate and subsequently distributed over the pathways leading to the formation of these products. These platform chemicals are produced in high yields on a wide range of carbon sources. The yields are in excess of 85 % of the theoretical yield for l-(+)-lactic acid and ethanol and over 65 % for fumaric acid. The study and optimization of the metabolic pathways involved in the production of these compounds requires well-developed metabolic engineering tools and knowledge of the genetic makeup of this organism. This review focuses on the current metabolic engineering techniques available for R. oryzae and their application on the metabolic pathways of the main fermentation products

La subsidence dans le Viking Graben (mer du Nord septentrionale) Subsidence in the Viking Graben (Northern Part of the North Sea)

L'utilisation des modèles numériques de calcul de la subsidence nécessite une bonne connaissance géologique de la zone étudiée. Seule une étude détaillée de stratigraphie sismique le long de profils régionaux passant par des forages permet de contraindre les différents paramètres servant au calcul de la subsidence. L'étude de la subsidence du Viking Graben a mis en évidence trois épisodes : - phase de distension permo-triasique (saalienne ?) dont l'axe de subsidence est décalé vers l'est par rapport à l'axe actuel du Viking Graben; - phase de distension jurassique supérieur (cimmérienne) qui crée les structures majeures de cette zone; - phase paléocène correspondant au contrecoup de l'ouverture plus à l'ouest de l'Atlantique Nord. Cette phase est surtout sensible à l'ouest de la zone étudiée. Les cartes de subsidence pour les différentes époques font apparaître l'influence du bati calédonien. Deux directions principales apparaissent, une NE-SW correspondant aux directions structurales visibles à terre en Ecosse et une NW-SE discrète qui sépare le Southern Viking Graben du Northern Viking Graben. Cette dernière direction pourrait se calquer sur la suture (au Silurien) d'un diverticule de l'océan lapétus, la Tornquist Sea. <br> The use of numerical models for computing subsidence requires a good geological understanding of the zone being examined. Detailed seismic stratigraphy along regional profiles going via boreholes is the only way to determine the different parameters required for computing subsidence. An investigation of the subsidence of the Viking Graben in the North Sea has revealed three episodes:(a) The Permo-Triassic (Saalian ?) distension phase during which the axis of subsidence lay to the east of the present axis of the Viking Graben. (b) The later Jurassic (Kimmerian) distension phase which created the major structures in this zone. (c) The Paleocene phase corresponding to the backlash of the westward opening of the North Atlantic. This phase is mainly appreciable west of the zone investigated. Subsidence maps for different eras reveal the influence of the Caledonian framework. Two principal directions appear, one NE-SW corresponding to structural directions visible in Scotland, and the other a more discreet NE-SW one separating the southern Viking Graben from the northern Viking Graben. This latter direction may be the reflection of the suture (in the Silurian) of a diverticulum of the Iapetus Ocean, i. e. the Tornquist Sea

Sédimentation et tectonique dans le bassin marin Eocène supérieur-Oligocène des Alpes du Sud

Des études de terrain détaillées ont été reprises récemment par l'Institut Français du Pétrole (IFP) et l'Ecole Nationale Supérieure du Pétrole et des Moteurs (ENSPM) dans la partie occidentale du bassin nummulitique des Alpes du Sud afin d'aider les interprétations de données sismiques. Ces études soulignent l'importance de la tectonique en distension qui a affecté le bassin durant la sédimentation; elles remettent en question l'interprétation géodynamique de ce bassin considéré classiquement comme une avant-fosse de la chaîne alpine en cours de formation. Sur un substratum mésozoïque structuré par la phase pyrénéo-provençale, la transgression nummulitique envahit dès le Lutétien les parties les plus basses du bassin situé à l'Est dans une zone qui sera oblitérée au Mio-Pliocène par l'accident pennique. Elle s'étend progressivement vers l'Ouest durant l'Eocène supérieur. Dans le même temps une phase de distension E-O bien visible le long des failles du Var et en bordure du Pelvoux se traduit par le compartimentage des bordures du bassin et par des jeux en blocs basculés durant la sédimentation. Dans les calcaires qui débutent la série marine, ces jeux sont responsables du passage rapide de faciès de plate-forme à des faciès resédimentés sur les pentes, puis à une sédimentation gravitaire de plus en plus réduite en s'éloignant des bordures. Les marnes sus-jacentes correspondent à des dépôts de talus qui soulignent la topographie héritée. Le passage à la sédimentation turbiditique des grès d'Annot s. l. , est corrélé avec le début d'une activité de rift sur le bloc corso-sarde et le changement climatique qui intervient à cette époque. Le dépôt de ces grès dont l'épaisseur maximale observée est de 1 200 m correspond à une phase de remplissage, avec des onlaps bien marqués soulignant les paléopentes. La distension E-O se poursuit durant la sédimentation des grès mais elle s'exprime nettement moins que précédemment. Le toit des grès est marqué par une surface de discontinuité fortement érosive correspondant à des canyons sous-marins de direction NE-SO. Cette surface peut être mise en relation avec l'écoulement des olistostromes qui termine le remplissage du bassin. La mise en place de ces olistostromes et des olistolithes qui les accompagnent n'est pas paléontologiquement datée : elle débute avec la fin de la sédimentation gréseuse. L'ensemble est encore affecté par une distension E-O ce qui tend à montrer que cette mise en place est antérieure à la phase de serrage miocène. La confrontation entre les observations de terrain, les expériences de sédimentation en canal et l'interprétation sismique de bassins offshore argumente les interprétations proposées

Geodynamics of the Gulf of Lions: implications for petroleum exploration

Volume: 170Start Page: 129End Page: 15

Discovery of continental stretching and oceanic spreading in the Tasman Sea

A deep seismic survey conducted within the western part of New Caledonia's Exclusive Economic Zone (EEZ) (Figure 1) from 8 September–5 October 2004 revealed for the first time the thinned continental and oceanic natures of the crust beneath the eastern Tasman Sea. The survey which was conducted by an international group of scientists a board the Institut Francais de Recherche pour l'Exploitation de la MER (Ifremer) R/V L'Atalante, aimed at improving the understanding of the geological framework, crustal characteristics, and evolution of the submarine basin and ridge system located west of New Caledonia's mainland. The study area, located east of both Australia and the oceanic Tasman Sea Basin, is composed of continental fragments: the Lord Howe Rise and the Norfolk Ridge, which are separated by the New Caledonia and Fairway basins

Oil Seeps from the "Boulganack" Mud Volcano in the Kerch Peninsula (Ukraine - Crimea), Study of the Mud and the Gas: Inferences for the Petroleum Potential

Mud volcanoes act as prospecting indices in the exploration of oil and gas deposits with gases and muds excreted. A methodology and an analytical protocol have been developed in order to classify the petroleum provinces according to the geochemical information available from the mud volcanoes. Such a study allows us to evaluate the potential of the petroleum system beneath. The Crimean-Caucasus region is renowned for mud volcano activity with well-known areas from west to east: Kerch Peninsula, Kuban and Azerbaijan. A methodology concerning the geochemical sampling and analysis of the mud volcanoes located onshore was applied to the Kerch Peninsula. Three field trips were organised by IFP in 2000, 2001 and 2002 in order to collect geochemical data, in agreement with the Museum of National History in Kiev. During these geological and geochemical surveys particular attention was given to the Boulganack mud volcano, which is a favourable site for the study of mud and gas samples due to the variety of the types of the vents. Specific tools were built in order to take samples of mud, up to 20 m deep in the vents, and gas more than 25 m away from the bubbling point in safe conditions in the deep mud lakes. Moreover, monitoring of the sampling of the gas was undertaken on the Boulganack mud volcano for one year in order to study the variation in the composition of the gas in time and space in the various vents. The proportions of nitrogen, carbon dioxide and hydrocarbons (methane to ethane) were measured. The vents of the Boulganack mud volcano present about 90% of methane and 10% CO2, with a few percent of heavier hydrocarbons in one particular vent: Andrusov. Pavlov expelled more CO2 (25% to 40%), with the greatest temporal variations. Only Obrudchev expels as much carbon dioxide as methane (50/50). Sometimes, nitrogen was also measured (Pavlov, Obrudchev and Central Lake). The high dryness of the gas implies a loss of heavy hydrocarbon compounds relative to a typical thermogenic gas. Chemical gas compounds are highly dependent from one vent to the other. The comparison of the quantity of hydrocarbon included in the mud released from the mud volcanoes of the Kerch Peninsula and those of Azerbaijan (used as a reference) shows very little hydrocarbon in the mud from the mud volcano in the Crimea, whereas accumulations of hydrocarbons exist in the fluids expelled from mud volcanoes in Azerbaijan. In fact, the ranking of the petroleum provinces is linked to the occurrence of the free hydrocarbons in the mud excreted by mud volcanoes. Analysis by chromatography of the saturated hydrocarbons presents a high degree of biodegradation when the samples are taken at the surface. When they are taken with the core barrel at greater depth in the vents, the hydrocarbons are preserved with a typical continental origin which can be compared with the organic matter of the Maykop formation. The modelling of the hydrocarbon window geohistory confirms that the hydrocarbons are mainly produced within the lower Maykop. The generation of gas is favoured, in agreement with the quality of the type III source rocks in this western part of the Caucasus

Transition from symmetry to asymmetry during continental rifting: An example from the Bight Basin-Terre Adélie (Australian and Antarctic conjugate margins)

International audienceThe rifting history of the magma-poor conjugate margins of Australia and Antarctica is still a controversial issue. In this article, we present a model for lithosphere-scale rifting and deformation history from initial Jurassic rifting to Late Cretaceous breakup for the conjugate Bight Basin-Terre Adélie section of the margin, based on the interpretation of two regional conjugate seismic profiles of the margins, and the construction of a lithosphere-scale, balanced cross-section, sequentially restored through time. The model scenario highlights the symmetric pattern of initial stretching resulting from pure shear at lithospheric-scale accompanied by the development of four conjugate detachments and crustal half-graben systems. This system progressively evolves to completely asymmetric shearing along a single south-dipping detachment at the scale of the lithosphere. Antarctica plays the role of the upper plate and Australia, the lower plate. The detachment accounts for the exhumation of the mantle part of the Australian lithosphere, and the isolation of a crustal klippe separated from the margin by a serpentinized peridotite ridge. The total elongation amount of the Australian-Antarctic conjugate system reaches ~473km (178%). Elongation was partitioned through time: ~189 and ~284km during symmetric and asymmetric stages respectively. During the symmetric stage, both margins underwent approximately the same degree of crustal stretching [~105km (75%) and ~84km (67%) for Australia and Antarctica respectively]. Again, both margins accommodated relatively the same elongation during the asymmetric stage: the Antarctic upper plate records an elongation amount of ~284km (88%) as crustal/mantle stretching, above the inferred low-angle south-dipping detachment zone, whereas the Australian lower plate underwent ~270km (206%) of elongation through mantle exhumation. Although the restoration process does not allow reconstruction of the precise geometry before deformation, we propose that the Jurassic early geometric evolution of the margins may have been controlled by the inherited structure or rheological heterogeneities of the continental crust; its later evolution is thought to relate to the mechanical evolution of the crustal and mantle material during exhumation, with a strong increase in localization of shear in the lower crust and mantle part of the Australian margin. The geometry of the rifted margins is comparable to other magma-poor rifted margin such as the Newfoundland-Iberia margins or the exhumed Alpine Tethys margin exposed in the Central Alps. © 2012 Blackwell Publishing Ltd

Deep Seated Density Anomalies Across the Iberia-Africa Plate Boundary and Its Topographic Response

The modes in which the lithosphere deforms during continental collision and the mechanisms involved are not well understood. While continental subduction and mantle delamination are often invoked in tectonophysical studies, these processes are difficult to be confirmed in more complex tectonic regions such as the Gibraltar Arc. We study the present-day density and compositional structure of the lithosphere along a transect running from South Iberia to North Africa crossing the western Gibraltar Arc. This region is located in the westernmost continental segment of the African-Eurasian plates, characterized by a diffuse transpressive plate boundary. An integrated and self-consistent geophysical-petrological methodology is used to model the lithosphere structure variations and the thermophysical properties of the upper mantle. The crustal structure is mainly constrained by seismic experiments and geological data, whereas the composition of the lithospheric mantle is constrained by xenolith data. The results show large lateral variations in the topography of the lithosphere-asthenosphere boundary. We distinguish different chemical lithospheric mantle domains that reproduce the main trends of the geophysical observables and the modeled P and S wave seismic velocities. A sublithospheric body colder than the surrounding mantle is needed beneath the Betics-Rif to adjust the measured potential fields. We link this body to the Iberian slab localized just to the east of the profile and having some effect on the geoid and Bouguer anomalies. Local isostasy allows explaining most of the topography, but an elastic thickness higher than 10 km is needed to explain local misfits between the Atlas and the Rif Mountains.Funding was granted by the Spanish Government through the project MITE (CGL2014‐59516‐P) and projects Alpimed (PIE‐CSIC‐201530E082) and Subtetis (PIE‐CSIC‐201830E039). A. C. benefitted from a JAE‐Pre‐CP grant from CSIC. A. K. benefitted from EU Marie Curie Initial Training Network “SUBITOP” (674899‐SUBITOP‐H2020‐MSCA‐ITN‐2015).Peer reviewe