Plant biology in space

Plant Biol.ISI Document Delivery No.: 277NVTimes Cited: 0Cited Reference Count: 24Ruyters, G. Spiero, F. Legue, V. Palme, K.Wiley-blackwellHoboken1Si[début du texte]In August 2012, more than 60 invited scientists and representatives of space agencies from different continents, nationalitiesand disciplines attended the international workshop on ‘Plant Biology Research in Space’, held at the University of Freiburg, Germany. This workshop – jointly organised by the French and German space agencies, CNES and DLR – was embedded as satellite symposium into the Plant Biology Congress 2012, held by FESPB and EPSO, the two leading European organisations involved in plant research. Using this setup, it was also hoped that scientists from the so-called nonspace community would be attracted to the specific topic of plant biology in space. This idea proved very successful: more than 600 participants attended – for instance – the plenary lecture from Stan Roux on ‘New insights in plant biology gained from space research’

Sustainability of a university designed and developed media annotation tool to prepare learners with skills needed for future employment

RMIT University‘s media annotation tool (MAT) is a computer software program dedicated to incorporating video footage to the student learning experience in a novel manner. In addition to the usual functions associated with videos, MAT allows users to enter written comments at strategic and key positions to emphasise the required learning points. Innovatively introduced to creatively support learning for work-ready skills, in 2011 MAT was integrated into courses across nine student cohorts, over six disciplines, in the Vocational and Higher Education (undergraduate and post graduate) sectors of the university. This paper will focus on analysis of insights of teacher experiences using MAT, highlighting sustainable ways forward with university designed innovations. It will introduce the context of implementing MAT and discuss the process of evaluating the requirements for promoting MAT to the wider university community and, more specifically, to embed and sustain MAT into the long-term

Low temperature dipolar echo in amorphous dielectrics: Significance of relaxation and decoherence free two level systems

The nature of dielectric echoes in amorphous solids at low temperatures is investigated. It is shown that at long delay times the echo amplitude is determined by a small subset of two level systems (TLS) having negligible relaxation and decoherence because of their weak coupling to phonons. The echo decay can then be described approximately by power law time dependencies with different powers at times longer and shorter than the typical TLS relaxation time. The theory is applied to recent measurements of two and three pulse dipolar echo in borosilicate glass BK7 and provides a perfect data fit in the broad time and temperature ranges under the assumption that there exist two TLS relaxation mechanisms due to TLS-phonons and TLS-TLS interaction. This interpretation is consistent with the previous experimental and theoretical investigations. Further experiments verifying the theory predictions are suggested.Comment: 10 pages, 8 figure

Selection of yeast strains for bioethanol production from UK seaweeds

Macroalgae (seaweeds) are a promising feedstock for the production of third generation bioethanol, since they have high carbohydrate contents, contain little or no lignin and are available in abundance. However, seaweeds typically contain a more diverse array of monomeric sugars than are commonly present in feedstocks derived from lignocellulosic material which are currently used for bioethanol production. Hence, identification of a suitable fermentative microorganism that can utilise the principal sugars released from the hydrolysis of macroalgae remains a major objective. The present study used a phenotypic microarray technique to screen 24 different yeast strains for their ability to metabolise individual monosaccharides commonly found in seaweeds, as well as hydrolysates following an acid pre-treatment of five native UK seaweed species (Laminaria digitata, Fucus serratus, Chondrus crispus, Palmaria palmata and Ulva lactuca). Five strains of yeast (three Saccharomyces spp, one Pichia sp and one Candida sp) were selected and subsequently evaluated for bioethanol production during fermentation of the hydrolysates. Four out of the five selected strains converted these monomeric sugars into bioethanol, with the highest ethanol yield (13 g L−1) resulting from a fermentation using C. crispus hydrolysate with Saccharomyces cerevisiae YPS128. This study demonstrated the novel application of a phenotypic microarray technique to screen for yeast capable of metabolising sugars present in seaweed hydrolysates; however, metabolic activity did not always imply fermentative production of ethanol

The worldwide NORM production and a fully automated gamma-ray spectrometer for their characterization

Materials containing radionuclides of natural origin, which is modified by human made processes and being subject to regulation because of their radioactivity are known as NORM. We present a brief review of the main categories of non-nuclear industries together with the levels of activity concentration in feed raw materials, products and waste, including mechanisms of radioisotope enrichments. The global management of NORM shows a high level of complexity, mainly due to different degrees of radioactivity enhancement and the huge amount of worldwide waste production. The future tendency of guidelines concerning environmental protection will require both a systematic monitoring based on the ever-increasing sampling and high performance of gamma ray spectroscopy. On the ground of these requirements a new low background fully automated high-resolution gamma-ray spectrometer MCA_Rad has been developed. The design of Pb and Cu shielding allowed to reach a background reduction of two order of magnitude with respect to laboratory radioactivity. A severe lowering of manpower cost is obtained through a fully automation system, which enables up to 24 samples to be measured without any human attendance. Two coupled HPGe detectors increase the detection efficiency, performing accurate measurements on sample volume (180 cc) with a reduction of sample transport cost of material. Details of the instrument calibration method are presented. MCA_Rad system can measure in less than one hour a typical NORM sample enriched in U and Th with some hundreds of Bq/kg, with an overall uncertainty less than 5%. Quality control of this method has been tested. Measurements of certified reference materials RGK-1, RGU-2 and RGTh-1 containing concentrations of K, U and Th comparable to NORM have been performed, resulting an overall relative discrepancy of 5% among central values within the reported uncertainty.Comment: 21 pages, 4 figures, 6 table

OLIGOMERIC FORMS OF GLYCOLYTIC-ENZYMES IN CHLORELLA GROWN IN DIFFERENT LIGHT QUALITIES

KOWALLIK W, Grotjohann N, RUYTERS G. OLIGOMERIC FORMS OF GLYCOLYTIC-ENZYMES IN CHLORELLA GROWN IN DIFFERENT LIGHT QUALITIES. BOTANICA ACTA. 1990;103(2):197-202

PROPERTIES OF OLIGOMERIC FORMS OF PHOSPHOFRUCTOKINASE FROM CHLORELLA-KESSLERI GROWN UNDER DIFFERENT LIGHT CONDITIONS

Grotjohann N, KOWALLIK W, RUYTERS G. PROPERTIES OF OLIGOMERIC FORMS OF PHOSPHOFRUCTOKINASE FROM CHLORELLA-KESSLERI GROWN UNDER DIFFERENT LIGHT CONDITIONS. BOTANICA ACTA. 1991;104(1):77-81.Fast protein liquid chromatography on Superose 6 of crude extracts from Chlorella kessleri, Fott et Novakova, grown autotrophically in blue or in red light yields there different oligomeric forms of phosphofructokinase (PFK, EC 2.7.1.11). Their substrate affinities and responses to homotropic and heterotropic effectors are different. In vitro, the degree of oligomerization of the enzyme can be influenced by specific intermediates or cofactors. Its substrate, MgATP (10 mM/5 mM), and the negative effector, phosphoenolpyruvate (5 mM), both lead to some dissociation, while the second substrate, fructose-6-phosphate (5 mM), and the positive effector, inorganic phosphate (50 mM), have no effect. It is discussed whether formation or dissociation of oligomeric PFK forms in vivo result from alterations in the levels or in the intracellular distribution of effector molecules and whether such processes are involved in the different regulation of cell metabolism in blue or in red light

OLIGOMERIC FORMS OF PYRUVATE-KINASE FROM CHLORELLA WITH DIFFERENT KINETIC-PROPERTIES

RUYTERS G, Grotjohann N, KOWALLIK W. OLIGOMERIC FORMS OF PYRUVATE-KINASE FROM CHLORELLA WITH DIFFERENT KINETIC-PROPERTIES. ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES. 1991;46(5-6):416-422.Fast protein liquid chromatography on Superose 6 of crude extracts from the chlorophyll-free mutant no. 20 of the unicellular green alga Chlorella kessleri reveals two possibly oligomeric forms of pyruvate kinase (2.7.1.40). Their occurrence is markedly altered in the course of heterotrophic growth with changing levels of exogenous glucose as carbon source with only one enzyme species with a MW of 400 kDa existing in growing cells, two forms of 400 and 580 kDa in resting cells. Substrate affinity towards PEP of the 400 kDa form is better than that of the 580 kDa species; responses to the effector AMP are different as well. In vitro, addition of PEP or of AMP leads to the formation of higher MW enzyme species with MW of 730, 1050 and 1400 kDa without affecting the total activity. In vivo alterations in the levels of several metabolites including PEP upon addition of glucose have been shown to occur. Therefore, it is discussed, whether changes in the concentration of intermediates and effectors may provide the mechanism for the increased rate of carbohydrate degradation by affecting the occurrence and/or ratio of the various PK forms with different kinetic and regulatory properties. Upon blue light irradiation, which also stimulates carbohydrate breakdown of the Chlorella mutant cells, the distribution of PK is shifted towards the species with higher substrate affinity, a result being in accordance with the above conception