Future developmentsFuture developments

• Further refinement of methods - unlock more information on how transformations that drive life on earth work - vital in the context of environmental degradation, growing human population and climate change - huge field of scientific endeavour

• Current research areas: What is the basis for natural methane emissions? What are the indicators of soil fertility and quality? What effect does loss of macroorganism biodiversity have? What are the specific effects of pollution?

Biotechnological applications of microbial ecology

Biotechnological applications of microbial ecology

• One of the largest areas of microbial biotechnology is waste and wastewater treatment

• Microbiological systems both aerobic and anaerobic used to treat sewage and industrial effluents to prevent environmental degradation and ensure water quality

• Also used to clean up contaminated sites - growing interest in using genetically engineered bacteria for this purpose

Practical areas of application of genetically engineered bacteriaPractical areas of application of genetically engineered bacteria

• Pseudomonas fluorescens - genetically altered to degrade polyaromatic hydrocarbons, commonly found in industrial wastes.

• Tracked by light emissions - bioluminescence

Deinococcus radioduransDeinococcus radiodurans

• Bacterium 1000’s of time more resistant to radiation than all other organisms

• Has unique and remarkable DNA repair - vitually 100% accurate and very rapid

• Genetically engineered to remove pollutants at radioactive sites

PesticidesSeveral bacteria engineered to enhance their ability to kill or repel pests have been approved for commercial use in US e.g Bacillus thuringensis

Food ProcessingE. coli has been genetically engineered to produce rennet, an enzyme important in making cheese. Approved for commercial use and widely used by US cheese processors.

Animal Drugs

Bovine Growth Hormone (BGH) made from engineered E. coli used commercially to stimulate milk production in cows. Used in about 10 percent of US dairy herds

Concerns…Concerns…

• Not enough information available on the natural environment - how can we predict impacts - and once released into the environment recovery is impossible

• Behaviour is essentially unpredictable

• Transfer of recombinant DNA to other, undesirable organisms is likely

• Risk may be small but the consequences of something going wrong could be catastrophic

• Advantages: represent an effective solution for many difficulties such as soil contamination, can be designed to die off quickly no residual problem, rapid and cheap production of important medicines.

• Disadvantages: Unknown impacts on the natural populations and ecology leading to undesirable and unpredictable outcomes. Potential for gene transfer in the environment, creation of new species (and pathogens) and unwanted new characteristics. Loss of diversity leading to increased sensitivity in habitats

Environmental Gene TransferEnvironmental Gene Transfer

• DNA can be tranferred between microbes in a number of different ways: via DNA uptake from dead cells (A), Plasmids (B) and phage infection (C)

• Plasmids are circular, mobile genetic elements capable of replication and transfer from one bacterium to another

Plasmids - SummaryPlasmids - Summary

• Several different types of plasmid classed into groups based on the genes they carry

• Plasmids have their own origin of replication and also can genetically control transfer

• Many plasmids carry antibiotic resistance and have been implicated in the spread of ab resistance, particularly in hospitals

• Major risk in introduction of GM organisms

Recommended ReadingRecommended Reading

• In addition to Brock: Microbial Ecology - Atlas and Bartha (4th edition)

• Lecture Notes Available On: www.nuigalway.ie/microbiology/mel/courses

Exam InformationExam Information

• 1 Question: Overview rather than detail on a single specific subject

• High marks for the ability to identify and summarise the important points and to cohesively illustrate your answer

• Information in notes will be the basis for majority of marks - supplementary information will be rewarded

GOOD LUCK!