Evaluation Of Adaptive Responses Research Articles

Progressive transitional studies of engineered Synechococcus from laboratory to outdoor pilot-scale cultivation for production of ethylene

Cyanobacterial research is impeded by the substantial discrepancies between laboratory studies and outdoor performances, despite successful demonstrations of genetically engineered strains for array of compounds. Therefore, evaluation of adaptive responses is necessary to achieve outdoor scale-up cultivation of cyanobacteria. Under current study, cyanobacterium Synechococcus elongatusPCC7942 engineered for ethylene biosynthesis, was gradually acclimatised, ensuring sustained and progressive transition from laboratory to outdoor conditions. Bubble size of 4.9 ± 0.2 mm and air-flow rate of 0.05 vvm in BG11 supplemented with 5 g/L bicarbonate giving mass transfer coefficient (KLa) of 10.48 h−1 yielded highest specific growth rate (0.24 h−1) with the transformants. At the 100 L photobioreactor scale, ethylene productivity of 1.5 mL.L-1.h−1 was achieved. A comprehensive investigation on photosynthetic responses of the transformants adapted to the outdoor conditions exhibited interesting photosynthetic electron transport regulations, involving antenna density modulation in response to diurnal and dynamic light transitions, indicating successful transition.

Evaluation of adaptive response in E. coli O157:H7 to UV light and gallic acid based antimicrobial treatments

Ability of bacteria to develop cross-protection to various stresses is well-known. However, exploration into cross-protection between conventional physiological stresses and emerging antimicrobial treatments is limited. Previously, we developed two new antimicrobial treatments based on a combined UV-A light and gallic acid (UVA + GA) treatment and enhanced antimicrobial action of gallic acid by UV-C exposure (UVC-GA) against Escherichia coli O157:H7. In this study, we investigated (a) whether prior exposure to sub-lethal stresses (heat, acid, osmotic and oxidation) can increase the resistance of E. coli O157:H7 towards these newly developed treatments, and (b) whether repeated exposure to these two treatments selects for E. coli O157:H7 sub-population resistant towards heat, acid, and oxidative challenge. Prior exposure to heat or acid stress increased (p < 0.05) the resistance of E. coli O157:H7 towards UVA + GA treatment, while osmotic stress increased (p < 0.05) their sensitivity to that treatment. Interestingly, only heat stress showed protective (p < 0.05) effect to subsequent UVC-GA treatment, while acid or osmotic stress increased (p < 0.05) the sensitivity. Prior exposure to oxidative stress had no effect (p > 0.05) on the sensitivity of the bacteria to either of the treatments. Repeated exposure to UVA + GA or UVC-GA treatment selected for a sub-population that demonstrated higher (p < 0.05) resistance towards these two treatments as well as heat or acid challenge. Further experiments showed that increased synthesis of enzymes such as superoxide dismutase and up-regulation of general stress response regulator were likely associated with the development of cross-protection. Thus, sub-lethal conditions encountered during food processing should be considered in the development and optimization of emerging non-thermal technologies.

Climate change in the uplands: a UK perspective on safeguarding regulatory ecosystem services

The UK uplands are highly sensitive and significant cultural landscapes that have been created by woodland clearance for agriculture and are at threat from fire, over-grazing, mineral extraction, land drainage, air pollution and recreation. Some of these activities increase upland sen- sitivity to climate change, contributing to increased flood risk, or soil carbon losses. Many distinct areas of public policy impinge on the uplands, but most have yet to integrate climate change protec- tion within their objectives. Placed within the emerging ecosystems services perspective, policies could be modified to deliver land management services to secure soil carbon stocks, and to protect the goods, services and functions that uplands deliver. There are, therefore, both new opportunities and threats to tackle. The present paper outlines climate sensitivity and change in the uplands; reviews adaptation and mitigation options; and considers available policy, information and manage- ment tools. Within an ecosystems framework, emphasis is placed on safeguarding key regulatory ser- vices. We offer a research agenda to support adaptation and outline measures that could be devel- oped within existing regulatory frameworks, or signal where policies may need revision. Research priorities include better quantification of carbon fluxes under different soils and land management practices, techniques for up-scaling local interventions to quantify landscape-scale benefits, and the evaluation of adaptive responses in the context of sustainable land use. Potential adaptation strate- gies include improved spatial planning for land and water, the creation of networked habitats to enable species migration, and practical guidance on appropriate locations for intensification and extensification of land use.