Construction and analysis of in vivo activity of E. coli promoter hybrids and promoter mutants that alter the -35 to -10 spacing

A series of promoter hybrids has been constructed by exchanging the ? 35 and ? 10 regions of lacUV5, tet, and trp promoters. These three promoters and the six hybrid promoters constructed from them have been inserted into a pKO plasmid which places galactokinase expression under the control of the inserted promoter. Additionally, promoter mutants were prepared which had altered the spacing between the ? 35 and ? 10 regions of the promoter. Derivatives of the tet promoter with one or two extra base pairs in this spacer region and constructions of the lac:: tet hybrid promoter with two different spacings have been inserted into the galactokinase expression plasmid. Measurements of galactokinase levels in strains harboring these plasmids permited the comparison of in vivo activities of the promoters. The strongest of the hybrid promoters (order: ? 35, ? 10) were trp:: lac and trp:: tet suggesting a high efficiency for the ? 35 region of the trp promoter. The weakest promoters were tet:: trp, lac:: trp and lac::tet indicating a weak ? 10 region for the trp promoter and the importance of ? 35 to ? 10 spacing. Analysis of activity of related promoters with differences in spacing indicated that a distance of 19 bp yields a very weak promoter, and that 18 bp is less active than the 17-bp spacing, which is the most frequently found spacing in promoters.     

Reactor design for large scale suspension animal cell culture

The scale of operation of freely suspended animal cell culture has been increasing and in order to meet the demand for recombinant therapeutic products, this increase is likely to continue. The most common reactor types used are stirred tanks. Air lift fermenters are also used, albeit less commonly. No specific guidelines have been published for large scale (≥10 000 L) animal cell culture and reactor designs are often based on those used for microbial systems. However, due to the large difference in energy inputs used for microbial and animal cell systems such designs may be far from optimal. In this review the importance of achieving a balance between mixing, mass transfer and shear effects is emphasised. The implications that meeting this balance has on design of vessels and operation, particularly in terms of strategies to ensure adequate mixing to achieve homogeneity in pH and dissolved gas concentrations are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

重工业城市(抚顺)实施清洁生产发展循环经济实例研究

论证了清洁生产与循环经济之间的关系 ,全面论述了发展循环经济的重要性、必要性及现实意义 ,提出了发展循环经济的切实可行的对策方案 ,为开创资源型城市可持续发展道路打下了扎实的理论基础。同时 ,以抚顺为研究对象 ,通过对其工业布局、产业结构、经济发展规模的分析 ,探索找出了重工业城市实施清洁生产的最佳途径。     

A new physical accounting model for material flows in urban systems with application to the Stockholm Royal Seaport District

Sustainable urbanization requires streamlining of resource management in urban systems which in turn requires understanding of urban metabolism (UM). Even though various methods have been applied for UM analysis, to date there is no standardized method for comprehensive accounting of material flows in urban systems. Moreover, the accounting of material flows is rarely implemented with a bottom‐up approach that can provide a thorough analysis of UM. This article presents the Urban Accounting Model (UAM) which aims to allow comprehensive accounting of urban material flows based on a bottom‐up approach. The model comprises two interlinked sub‐models. The first was developed by integrating a new physical input output table (PIOT) framework for urban systems into a three‐dimensional structure. The second comprises a set of physical accounts for systematic accounting of material flows of each economic sector in the system in order to support the compilation of the PIOTs. The functions of the UAM were explored through its application to two urban neighborhoods in the Stockholm Royal Seaport district. The application highlighted that the UAM can describe the physical interactions between the urban system and the environment or other socioeconomic systems, and capture the intersectoral flows within the system. Moreover, its accounts provide information that allow an in‐depth analysis of the metabolism of specific sectors. Overall, the UAM can function as a useful tool for UM analysis as it systematizes data collection and at the same time depicts the physical reality of the urban system.     

The occurrence and effectiveness of hypersensitive reaction against galling herbivores across host taxa

1. Hypersensitive reaction is an important type of induced defence by which the plant elicits a defence response to pathogens and insects. Hypersensitive reaction has been argued to be the most common plant resistance mechanism against insect herbivores that have intimate associations with their host plants. 2. The work reported here attempted to establish how important and widespread hypersensitive reaction might be against gall‐forming species across host taxa. 3. Hypersensitive reaction was the most important mortality factor against gall formation across host plant taxa in seven out of eight cases. 4. The number of insect galls correlated with the size of the leaves but module (leaf) size was a weak factor influencing the incidence of plant hypersensitive reaction to galling. 5. Insect galls and hypersensitive reactions occurred in genetically distant as well as geographically widespread host plant taxa.     

Fish induced macrophyte loss in shallow lakes: top–down and bottom–up processes in mesocosm experiments

SUMMARY 1. Macrophyte loss from Sites of Special Scientific Interest in England has become widespread over the last 20 years. One reason for this may be changing trends in angling, a multimillion pound industry that has an enormous impact on aquatic ecosystems. Stocking with cyprinid fish is a common angling management practice but the particular fish species and distribution of their biomass may be crucial to the ecosystem. 2. Carp (Cyprinus carpio), roach (Rutilus rutilus), bream (Abramis brama) and tench (Tinca tinca) at biomasses ranging from 0 to 800 kg ha^?1 and at various sizes were placed into experimental mesocosms in Little Mere, a shallow, fertile lake in Cheshire, U.K. The effects these treatments had on the aquatic ecosystem were studied over two summers. Specifically the effects of the treatments on macrophyte growth, benthic and macrophytic macro‐invertebrate populations, water chemistry, epiphyton production and plankton survival were investigated. 3. Carp had a greater detrimental effect on the macrophytes than bream, tench and in particular roach. A biomass of fish > 200 kg ha^?1 adversely affected the extent of macrophyte growth. 4. The decline in macrophyte growth was most likely as a result of increased epiphyton growth that probably reduced the amount of light and carbon dioxide available to the plant. There were no observed direct fish impacts on macrophytes. 5. The chemical data suggested that inorganic nitrogen levels were low and it is possible that release of nitrogen, from fish excreta, followed by immediate uptake, could have been a major factor stimulating epiphyton growth and subsequently macrophyte loss. Phosphorus concentrations increased even in the controls and substantial amounts were available. Phosphorus stimulation can therefore be discounted. Macrophyte‐associated macro‐invertebrates were positively correlated with epiphyton load but had no impact on the extent of epiphytic growth. Shading from disturbed sediment or phytoplankton was also unimportant.     

Uncertainty Analysis and Toxicity Classification in Life-Cycle Assessment Using the Case-study of Gas Purification Systems

This comprehensive thesis structures the decision-making process for making a choice of the most adequate gas purification system (GasPS). Various gas purification technologies (biofilter, activated carbon filter, catalytic oxidation, thermo-reactor) have been evaluated based on an industrial case-study for waste gas streams. The ecological performance was quantified using the life-cycle impact assessment methods Eco-Indicator 95 and Swiss Ecopoints (environmental scarcities). Both life-cycle impact assessment methods have been improved by a new classification method for volatile organic compounds (VOCs) which considers the environmental fate and exposure as well as the toxicity of these compounds. For life-cycle assessment, a detailed quantitative uncertainty analysis was carried out using Monte Carlo simulation. Based on the uncertainty analysis, developing statements about the significance of the results and of relative differences between various GasPS alternatives has been possible. The eco-efficiency of the investigated GasPSs was finally characterised based on four indicators: Net Ecological Benefit (NEB_N), Ecological Yield Efficiency (lgEYE), Net Present Value (NPV), and Ecological-Economic Efficiency (EEE).     

Influence of temporal fluctuations in seed abundance on the diet of harvester ants (Pogonomyrmex spp.) in the central Monte desert,Argentina

Harvester ants usually go through temporal fluctuations in environmental seed abundance and composition which could influence their behaviour and ecology. The aim of this study was to evaluate how these fluctuations influence the diet of Pogonomyrmex rastratus, P. pronotalis and P. inermis (Hymenoptera, Formicidae) in the central Monte desert during three consecutive growing seasons. Although seeds were the main item in the diet, these ants turned more generalist when seed abundance of the most consumed species (grasses Aristida spp., Trichloris crinita, Pappophorum spp., Digitaria californica and Stipa ichu) was low. Accordingly, diversity of items in the diet decreased with seed abundance in a logarithmical fashion, showing higher foraging efficiency for seeds at higher seed abundance. Seed diversity, however, was not related to seed abundance as ants always included several species in their diet, with alternating prevalence. The proportion of the most consumed species increased logarithmically in the diet of P. rastratus and P. pronotalis along with their abundance in the environment probably as a consequence of diet switching (from forb and shrub seeds to grass seeds) and by an increase in foraging efficiency at higher seed densities. In contrast, foraging activity of P. inermis was very low at low seed abundance and its diet included only the five grasses. Among the most consumed species, proportion in the diet was not associated with relative abundance in the environment. Aristida spp., Pappophorum spp. and D. californica were overall highly selected. However, the flexibility in the diet of P. pronotalis and P. rastratus and the low foraging activity of P. inermis during periods of low resource abundance could attenuate potential top‐down effects in the central Monte desert. This study shows that bottom‐up effects are important in ant‐seed interactions and should be considered when predicting and evaluating ants' effects on seed resources.     

Clinical analysis of human umbilical cord mesenchymal stem cell allotransplantation in patients with premature ovarian insufficiency

ObjectivePremature ovarian insufficiency (POI) is a refractory disease that seriously affects female fertility. Growing body of evidence has indicated mesenchymal stem cells (MSCs) as promising resources in regenerative medicine. In this study, we treated POI patients with umbilical cord‐derived MSCs (UCMSCs) and then investigated the restoration of ovarian function and clinical outcomes through follow‐ups.Materials and methodsSixty‐one patients diagnosed with POI participated in this study. UCMSCs were isolated and cultured according to GMP standards, and then transplanted to the patients’ ovary by orthotopic injection under the guidance of vaginal ultrasound. We monitored side effects, vital signs and changes in clinical and collected haematological and imaging parameters during the follow‐ups.ResultsAll patients showed normal clinical behaviour without serious side effects or complications relevant to the treatment. Transplantation of UCMSCs rescued the ovarian function of POI patients, as indicated by increased follicular development and improved egg collection. POI patients who experienced shorter amenorrhoea durations (<1 year) seemed to obtain mature follicles more easily after stem cell therapy, and patients with better ovarian conditions (pre‐operative antral follicles) were more likely to derive the better outcomes by UCMSC injection. Four successful clinical deliveries were obtained from POI patients after UCMSC transplantation, and all of these babies are developed normally.ConclusionsThe clinical trial result sugggests a possible therapy for POI by UCMSC transplantation.     

Effect of plant nitrogen and water status on the foraging behavior and fitness of an omnivorous arthropod

Omnivorous arthropods make dietary choices according to the environment in which they forage, mainly availability/quality of plant and/or prey resources. Such decisions and their subsequent impacts on life‐history traits may be affected by the availability of nutrients and water to plants, that is, through bottom‐up forces. By setting up arenas for feeding behavior observation as well as glasshouse cages for plant preference assessment, we studied effects of the presence of prey (Lepidoptera eggs) and nitrogen/water availability to host tomato plants on the foraging behavior and life‐history traits in the omnivorous predator Macrolophus pygmaeus (Heteroptera: Miridae). In the absence of prey, the predator fed equally on the plants treated with various levels of nitrogen and water. In the presence of prey, however, the feeding rate on plants decreased when the plant received low water input. The feeding rate on prey was positively correlated with feeding rate on plants; that is, prey feeding increased with plant feeding when the plants received high water input. Moreover, plants receiving high water input attracted more M. pygmaeus adults compared with those receiving low water input. For M. pygmaeus fitness, the presence of prey enhanced its fertility and longevity, but the longevity decreased when plants received low compared with high water input. In conclusion, the omnivorous predator may be obliged to feed on plants to obtain water, and plant water status may be a limiting factor for the foraging behavior and fitness of the omnivorous predator.