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Genetic manipulation of a cyanobacterium for heavy metal detoxivication

Description: Increasing heavy metal contamination of soil and water has produced a need for economical and effective methods to reduce toxic buildup of these materials. Biological systems use metallothionein proteins to sequester such metals as Cu, Cd, and Zn. Studies are underway to genetically engineer a cyanobacteria strain with increased ability for metallothionein production and increased sequestration capacity. Cyanobacteria require only sunlight and CO{sub 2}. Vector constructs are being developed in a naturally competent, unicellular cyanobacterium Anacystis nidulans R2. Closed copies of a yeast copper metallothionein gene have been inserted into a cyanobacterial shuttle vector as well as a vector designed for genomic integration. Transformation studies have produced recombinant cyanobacteria from both of these systems, and work is currently underway to assess the organism`s ability to withstand increasing Cu, Cd, and Zn concentrations.
Date: December 31, 1995
Creator: McCormick, P.; Cannon, G. & Heinhorst, S.
Partner: UNT Libraries Government Documents Department

Recent developments in ecological theory: hierarchy and scale

Description: Over the past decade, hierarchy and scale have been adopted as an ecological paradigm. Beyond this new awareness, however, a number of studies have attempted to test the underlying hierarchy theory and developed new analytical applications. The purpose of the present paper is to review these recent developments. Tests of the theory have focused on the prediction that ecological systems should not be uniformly distributed across scale, but grouped or lumped into discrete levels. The predicted breaks in spatial distribution have been found in vegetation transects. Vertebrate weight distributions are also distinctly aggregated, corresponding to the spatial scale at which each species operates. An important development of hierarchy theory has considered extrapolating information upscale. Simply stated, the dynamics of the higher level cannot be represented by the same functional form as its components. One cannot insert the mean parameter value for the components and predict higher level effects. Analytical methods, derived from hierarchy theory, have been developed deal with the problem.
Date: December 31, 1995
Creator: O`Neill, R.V.
Partner: UNT Libraries Government Documents Department

Photosynthesis, environmental change, and plant adaptation: Research topics in plant molecular ecology. Summary report of a workshop

Description: As we approach the 21st Century, it is becoming increasingly clear that human activities, primarily related to energy extraction and use, will lead to marked environmental changes at the local, regional, and global levels. The realized and the potential photosynthetic performance of plants is determined by a combination of intrinsic genetic information and extrinsic environmental factors, especially climate. It is essential that the effects of environmental changes on the photosynthetic competence of individual species, communities, and ecosystems be accurately assessed. From October 24 to 26, 1993, a group of scientists specializing in various aspects of plant science met to discuss how our predictive capabilities could be improved by developing a more rational, mechanistic approach to relating photosynthetic processes to environmental factors. A consensus emerged that achieving this goal requires multidisciplinary research efforts that combine tools and techniques of genetics, molecular biology, biophysics, biochemistry, and physiology to understand the principles, mechanisms, and limitations of evolutional adaptation and physiological acclimation of photosynthetic processes. Many of these basic tools and techniques, often developed in other fields of science, already are available but have not been applied in a coherent, coordinated fashion to ecological research. The efforts of this research program are related to the broader efforts to develop more realistic prognostic models to forecast climate change that include photosynthetic responses and feedbacks at the regional and ecosystem levels.
Date: July 1, 1995
Partner: UNT Libraries Government Documents Department