Proteomic analysis reveals differences between Vitis vinifera L. cv. Chardonnay and cv. Cabernet Sauvignon and their responses to water deficit and salinity

The impact of water deficit and salt stress on two important wine grape cultivars, Chardonnay and Cabernet Sauvignon, was investigated. Plants were exposed to increasing salinity and water deficit stress over a 16 d time period. Measurements of stem water potentials, and shoot and leaf lengths indicated that Chardonnay was more tolerant to these stresses than Cabernet Sauvignon. Shoot tips were harvested every 8 d for proteomic analysis using a trichloroacetic acid/acetone extraction protocol and two-dimensional gel electrophoresis. Proteins were stained with Coomassie Brilliant Blue, quantified, and then 191 unique proteins were identified using matrix-assisted laser desorption ionization time of flight/time of flight mass spectrometry. Peptide sequences were matched against both the NCBI nr and TIGR Vitis expressed sequence tag (EST) databases that had been implemented with all public Vitis sequences. Approximately 44% of the protein isoforms could be identified. Analysis of variance indicated that varietal difference was the main source of protein expression variation (40%). In stressed plants, reduction of the amount of proteins involved with photosynthesis, protein synthesis, and protein destination was correlated with the inhibition of shoot elongation. Many of the proteins up-regulated in Chardonnay were of unclassified or of unknown function, whereas proteins specifically up-regulated in Cabernet Sauvignon were involved in protein metabolism.     

Adding handles to unhandy substrates: anaerobic hydrocarbon activation mechanisms

In spite of their chemical inertness, hydrocarbons are degraded by microorganisms in the complete absence of oxygen. As all known aerobic hydrocarbon degradation pathways start with oxygen-dependent reactions, hydrocarbon catabolism in anaerobes must be initiated by novel biochemical reactions. In recent years, the enzymes catalyzing oxygen-independent activation of several hydrocarbons have been identified. Surprisingly, a variety of reactions seems to be employed to overcome the activation barrier of different hydrocarbons. This review presents the current understanding on some of these reactions and the associated degradation pathways: oxygen-independent hydroxylation as employed in ethylbenzene metabolism, fumarate addition to methyl or methylene carbons in toluene or alkane degradation, and only recently discovered reactions such as methylation of naphthalene or anaerobic methane oxidation via reverse methanogenesis.     

Did an ancient chlamydial endosymbiosis facilitate the establishment of primary plastids?

Background  

Ancient endosymbioses are responsible for the origins of mitochondria and plastids, and they contribute to the divergence of several major eukaryotic groups. Although chlamydiae, a group of obligate intracellular bacteria, are not found in plants, an unexpected number of chlamydial genes are most similar to plant homologs, which, interestingly, often contain a plastid-targeting signal. This observation has prompted several hypotheses, including gene transfer between chlamydiae and plant-related groups and an ancestral relationship between chlamydiae and cyanobacteria.     

The influence of various storage conditions on cell viability in amniotic membrane

Up to now freeze-dried, gamma-sterilised or glycerol-preserved amniotic membranes (AMs) have widely been used in the field of ophthalmology and wound care (e.g. leg ulcers, burns). After some preservation processes in use, like freeze-drying or glycerol-preserving, the cells in the AM are no longer viable. Within this study we evaluated the influence of different short-term and long-term storage conditions on cell viability in AM. Therefore AMs from cesarean section placentae were washed and biopsied to evaluate the microbiological status and to determine the viability of the tissue. Additionally, viability under various storage conditions was examined by assessment of mitochondrial activity. Preservation included temperatures above and below 0°C as well as various media compositions. As expected, cell viability in amnion decreases during storage, in fact the effect was more pronounced when stored frozen, but the higher viability of amnion obtained by storage above 0°C with medium is associated with the limitation to a short period of storage of about 28 days. The evaluated preservation methods are the basis for future non-clinical in-vivo studies in which the possible benefit of amnion as a viable biomaterial in wound healing will be investigated. A part of this work was presented at the World Congress on Tissue Banking in Rio in May 2005 and was honoured by the Poster Award Commission.     

The microbial metabolic activity on carbohydrates and polymers impact the biodegradability of landfilled solid waste

Biodegradation - Biological waste degradation is the main driving factor for landfill emissions. In a 2-year laboratory experiment simulating different landfill in-situ aeration scenarios, the...     

Engineering Saccharomyces cerevisiae for direct conversion of raw,uncooked or granular starch to ethanol

The production of raw starch-degrading amylases by recombinant Saccharomyces cerevisiae provides opportunities for the direct hydrolysis and fermentation of raw starch to ethanol without cooking or exogenous enzyme addition. Such a consolidated bioprocess (CBP) for raw starch fermentation will substantially reduce costs associated with energy usage and commercial granular starch hydrolyzing (GSH) enzymes. The core purpose of this review is to provide comprehensive insight into the physiological impact of recombinant amylase production on the ethanol-producing yeast. Key production parameters, based on outcomes from modifications to the yeast genome and levels of amylase production, were compared to key benchmark data. In turn, these outcomes are of significance from a process point of view to highlight shortcomings in the current state of the art of raw starch fermentation yeast compared to a set of industrial standards. Therefore, this study provides an integrated critical assessment of physiology, genetics and process aspects of recombinant raw starch fermenting yeast in relation to presently used technology. Various approaches to strain development were compared on a common basis of quantitative performance measures, including the extent of hydrolysis, fermentation-hydrolysis yield and productivity. Key findings showed that levels of α-amylase required for raw starch hydrolysis far exceeded enzyme levels for soluble starch hydrolysis, pointing to a pre-requisite for excess α-amylase compared to glucoamylase for efficient raw starch hydrolysis. However, the physiological limitations of amylase production by yeast, requiring high biomass concentrations and long cultivation periods for sufficient enzyme accumulation under anaerobic conditions, remained a substantial challenge. Accordingly, the fermentation performance of the recombinant S. cerevisiae strains reviewed in this study could not match the performance of conventional starch fermentation processes, based either on starch cooking and/or exogenous amylase enzyme addition. As an alternative strategy, the addition of exogenous GSH enzymes during early stages of raw starch fermentation may prove to be a viable approach for industrial application of recombinant S. cerevisiae, with the process still benefitting from amylase production by CBP yeast during later stages of cultivation.     

Minimizing the biodiversity impact of Neotropical oil palm development

Oil palm agriculture is rapidly expanding in the Neotropics, at the expense of a range of natural and seminatural habitats. A key question is how this expansion should be managed to reduce negative impacts on biodiversity. Focusing on the Llanos of Colombia, a mixed grassland–forest system identified as a priority zone for future oil palm development, we survey communities of ants, dung beetles, birds and herpetofauna occurring in oil palm plantations and the other principal form of agriculture in the region – improved cattle pasture – together with those of surrounding natural forests. We show that oil palm plantations have similar or higher species richness across all four taxonomic groups than improved pasture. For dung beetles, species richness in oil palm was equal to that of forest, whereas the other three taxa had highest species richness in forests. Hierarchical modelling of species occupancy probabilities indicated that oil palm plantations supported a higher proportion of species characteristic of forests than did cattle pastures. Across the bird community, occupancy probabilities within oil palm were positively influenced by increasing forest cover in a surrounding 250 m radius, whereas surrounding forest cover did not strongly influence the occurrence of other taxonomic groups in oil palm. Overall, our results suggest that the conversion of existing improved pastures to oil palm has limited negative impacts on biodiversity. As such, existing cattle pastures of the Colombian Llanos could offer a key opportunity to meet governmental targets for oil palm development without incurring significant biodiversity costs. Our results also highlight the value of preserving remnant forests within these agricultural landscapes, protecting high biodiversity and exporting avian ‘spill‐over’ effects into oil palm plantations.