Genetically Engineered Microorganisms - Research Paper Example

Genetically Engineered Microorganisms: Opportunities and Pitfalls Genetically engineered micro-organisms (GEM) are thosemicroorganisms where DNA from many organisms have been inserted into prokaryotic, eukaryotic and other viral hosts creating a new ‘novel’ genetic material. These techniques are generally referred to as recombinant DNA technology – a process where molecules from different sources are combined to form a new set of genetic material. The new DNA material is then transferred into an organism, giving it a new set of genes, thereby creating what is called transgenic organisms. (Alun and Morgan 91). The new technology involves genetic engineering is also termed as “genetic manipulation, bioengineering or applied genetics has caught the public attention and has been the focus of extensive public debate. The controversy has centered on the application of organisms altered by the introduction of recombinant DNA (rDNA) molecules. Organisms modified by cell fusion, transformation, transduction and use of mutagenic acid, are also included in the debate” (Colwell 41). Genetic engineering traces its origins from the discovery of bacterial enzymes called restriction endonucleases (Res) in the 1960s. REs cut “DNA into pieces by making breaks in the sugar-phosphate backbone”. They do not cut however at random, but rather, “breaks the DNA in a precise and reproducible manner…by cutting only at specific recognition sites, (at) sequences of typically four to six nucleotides” (Hogg 315). The simple genetic make-up of bacteria made them the first organisms to be modified in a laboratory. Genetic engineering is being applied since the 1970s, when insulin was first produced through recombinant techniques. During those times, “although bovine and porcine insulin are similar to human insulin, their composition is slightly different. Consequently, a number of patients' immune systems produce antibodies against it, neutralizing its actions and resulting in inflammatory responses at injection sites. Added to these adverse effects of bovine and porcine insulin, were fears of long term complications ensuing from the regular injection of a foreign substance, as well as a projected decline in the production of animal derived insulin. These factors led researchers to consider synthesizing humulin by inserting the insulin gene into a suitable vector, the E. coli bacterial cell, to produce insulin that is chemically identical to its naturally produced counterpart.” (Recombinant DNA Technology in the Synthesis of Human Insulin par. 2). Continued research and development of new equipment contributed to many advances in genetic engineering techniques “have allowed researchers to manipulate the makeup of microorganisms to either impart new abilities or enhance those already present” (Lada 11). Present Day Uses of GEM The manipulation of microorganisms have long been “applied for example, (in the) rotation of leguminous crops for soil fertilization, selective breeding of animals to create progeny of higher reproductive capacity, introduction of ‘exotic’ species into non-indigenous environments, production of organic acids, antibiotics, alcohol, food and as biocontrol agents” (Colwell par. 41). In medicine, genetic engineering has produced a variety of drugs and hormones. “Interferon, used to eliminate certain viruses and kill cancer cells, is a product of genetic engineering, as are tissue plasminogen activator and urokinase, which are used to dissolve blood clots. Another byproduct is a type of human growth hormone used to treat dwarfism and is produced through genetically engineered bacteria and yeasts” (Discovery Channel What are some important uses of genetic engineering? Par. 1). In the United Kingdom, researchers developed a treatment against inflammatory bowel disease (IBD) by using the bacterium Bacteroides ovatus which “activates a protein when exposed to a specific type of sugar, xylan. The bacterium is able to deliver the protein, a human growth factor called KGF-2, directly to the damaged cells that line the gut, unlike other treatments which can cause unwanted side effects. It reduced rectal bleeding, accelerated the healing of the gut lining, and reduced inflammation. It was also able to prevent the onset of disease. The bacterium is being used to produce other protein molecules to treat various bowel disorders (Genetically Engineered Bacteria are Sweet Success Against Inflammatory Bowel Disease, par 1 -4). In the United States, the Department of Energy engineered Escherichia coli bacteria which can synthesize and digest the biomass of switchgrass without the addition of enzymes, enabling the reduction of “(bio)fuel production costs by consolidating two steps -- depolymerizing cellulose and hemicellulose into sugars, and fermenting the sugars into fuels -- into a single step or one pot operation. E. coli bacteria normally cannot grow on switchgrass, but JBEI researchers engineered strains of the bacteria to express several enzymes that enable them to digest cellulose and hemicellulose and use one or the other for growth. These cellulolytic and hemicellulolytic strains of E. coli, which can be combined as co-cultures on a sample of switchgrass, were further engineered with three metabolic pathways that enabled the E. coli to produce fuel substitute or precursor molecules suitable for gasoline, diesel and jet engines. While this is not the first demonstration of E. coli producing gasoline and diesel from sugars, it is the first demonstration of E. coli producing all three forms of transportation fuels. Furthermore, it was done using switchgrass, which is among the most highly touted of the potential feedstocks for advanced biofuels” (Bokinsky et al.). Bacteria are now also being used in cleaning up crude oil spillages. The Pseudomonas strain, formerly only able to attack a limited number of hydrocarbons, have now been constructed to contain several plasmids which could attack hydrocarbons. A plasmid (factor K) was transferred as a mediator “that induces the mobilization of genes from the chromosome and recipient cells. Thus the range of compounds that these bacteria attack was extended” with the degradation of about 60% of crude oil (Klingmuller, p. 1). New bacterial strains have also been developed to bind nitrogen from the air and thereby improving soil fertility. Genes for nitrogen fixation were transferred via plasmids to soil bacteria of different types. This development, once disseminated, would effectively reduce the use of nitrogen fertilizers worldwide (Klingmuller p. 2). Scientists at the University of Washington have developed a microbe capable of digesting and converting seaweed into ethanol or other fuels and chemicals. Genes attributed to breaking down alginate were place into E. coli cells with favorable results (Biello par. 1-5). Newlight Technologies in the United States have developed a “carbon negative” plastic made with biocatalysts or microbes which “turn waste gas, or even normal air, into plastic by recombining oxygen and carbon molecules into the shape of bottles, dashboards or other plastic products” (Coren par.2-3). At the University of California in 2010, researchers have advanced in the programming of a genetic sensor in the engineering of a bacteria to keep track of time by the “turning on and off (of) fluorescent proteins within their cells. The scientists synchronized these ‘genetic clocks’ to blink in unison and altered their blinking rates when environmental conditions change”. Scientists believe that the synchronized genetic clock can be used “as macroscopic biosensors (for use as a) synchronized periodic signal in drug delivery” (Researchers Synchronize Blinking ‘Genetic Clock’ Using Bacteria par. 1 and 12). Picture 1. “A Supernova burst in a colony of coupled genetic clocks” From: University of California, San Diego) In Israel, Tel Aviv University researchers have genetically engineered bacteria which would measure water quality, by lighting up “when in contact with pre-determined pollutants. It’s a nano-sized version that detects and communicate ‘contact’ with existing monitoring systems” (Genetically Engineered Bacteria to Measure Water Quality, 2009). Other Potential Uses of GEM Microorganisms in the past were the source of disease, plague and other infections. Through the manipulation of the genetic material of microbes, they are being transformed into little helpers of man and the environment. In Discovery Magazine (August 2008), Susannah Locke listed some potential applications of genetically engineered microbes which could be beneficial to man. These are: Artemisinin, a drug used to treat malaria, is very expensive to synthesize. Scientists however have already engineered yeast cells which can produce the basic chemicals of the medicine. “Lactobacillus, a natural resident of the vaginal and gastrointestinal tracts, defends against urinary infections and diarrhea. Osel, a bacterial therapeutics company, (has determined that) the microbe may be genetically enhanced to manufacture proteins that target and attack HIV (Locke). Researchers at Introgen Therapeutics are modifying several genes in adenoviruses to “deploy anticancer genes in tumors (to kill) cancer cells while leaving healthy ones unscathed” (Locke). Silicon Valley researchers discovered a promising alternative fuel source…by genetically engineering bacteria and yeast able to convert fatty acids into petroleum replacement products. In this process, the organisms can produce hydrocarbon-based fuels from organic waste. In addition to being renewable, this “Oil 2.0,’ as the researchers call it, is also carbon neutral—the microbes use about the same amount of carbon to produce the oil as will be emitted when it burns” (Locke). In England, Dartmouth researchers engineered the E. coli bacteria and “developed a vacuum pump that infuses the bacteria into textile fibers. Possible applications would be self-cleaning clothes in which the bacteria feed on human sweat and dirt, bandages that can eat odors, repel water, glow in the dark, or release healing agents directly into wounds” (Locke). Researchers at MIT have taken advantage of virus’ ability to attach to anything “and created viruses to target inanimate objects, by genetically engineering viruses to produce proteins that attach to specific metal alloys at stress points in airplanes. In a few years, they say, technicians may be able to cover an airplane wing with microbes, detect what areas are in greater danger of failure, and fix them before take-off” (Locke). The continuing release of carbon dioxide through human activities is one cause for global warming and indirectly causing climate change. Researchers at the Lawrence Berkeley Laboratory’s Center for Nanoscale Control of Geologic CO2, believe that capturing these gasses and trapping it in underground rocks would lower the risk of climate change. Scientists “inserted a short DNA sequence that coded for a loop of six glutamic acids into C. vibrioides. The loop sticks out of the bacteria's surface protein and is repeated over the entire surface of the bacteria in a hexagonal pattern. Each six-acid loop contains six negative charges. The team reasoned that this "negative loop" could fit neatly around positively charged calcium ions in water, attracting them to the surface of the bacteria and coaxing them to form CaCO3…in the crystalline calcite form, which is more stable—and likely to sequester CO2 over geological time—than amorphous CaCO3. Other broad applications (may include), stabilizing soil in flood zones, isolating radioactive isotopes, and identifying early life in the fossil record by tracking changes in carbonate mineralization” (Krieger par.3-5). Issues on the Release of GEMs Man has since time been in search of solutions to control diseases and improve the productivity of agriculture, livestock and the development of synthetic products. Human actions have already significantly impacted ecosystems causing changes in species composition, adaptation and even the global climate. Some have proven to be beneficial to man, like the increase in food production, yet these introductions of improved species have also resulted to some negative effects on biodiversity and the natural ecosystem. Several issues face the release of genetically engineered microorganisms into the natural environments. In general terms, questions on the effects and hazards it may pose on human, animal and plant life, air, water and soil quality and possible effects on biodiversity. Sheldon Krimsky (1991) stated that the effects of releasing GEMs into the natural environment still needs further study as “the effects of microorganisms are not as obvious as those of plants and animals (since they) reproduce quickly and are impossible to recall; can move about in the environment; and, exchange DNA with other species” (37-38). Vassili V. Venkov in his study Stress-induced evolution and the biosafety of genetically modified microorganisms released into the environment (2001), concluded that certain “environmental conditions can influence released GEMs to evolve…(but) the inactivation of some genes responsible for such escape may considerably reduce the risks…” (667-683). Rita Colwell stated that public debate on the issue generated undue attention as natural mutation was quickened, and the public is not yet ready to accept such drastic changes. She adds that the “creation of new genetic material coupled with the speed of development and application, fueled by horror stories and exaggeration , has lowered the threshold of public concern and increased its attention to biotechnology” (Colwell 41-42). The National Research Council in 2004, cautioned about the inadequacy of knowledge on how transgenic microbes behave in the wild. It adds that “microbes occur in large populations and short generation times and can adapt quickly to adverse conditions…(with) bacteria transferring DNA into unrelated microbes and the long term ecological consequences unclear”. The combination of genes from unrelated organisms also offer potential threats to man and the present ecological systems as the genetic information, engineered into these new organisms, can be passed onto off-springs. As engineered organisms exhibit traits not naturally evolved on in the natural environment, the resulting impacts on the ecosystem is unknown. It is in this view that during the Convention on Biological Diversity in 1995, an “international action on biosafety was recognized and biosafety protocol(s)” were then developed (Scientists Working Group on Biosafety 2-4). Krimsky categorized genetically engineered organisms into plants, animals and microorganisms and stated that of “the three, microorganisms are (the) least likely to be recalled or destroyed once released…(thereby) perceived by some to represent a heightened area of concern for intentional release”. She adds that “extrapolating (the effects on the ecosystem) from one microbial species to another or from tests conducted under one set of environmental conditions to another is often unreliable” (38-40). It is in this view that the Convention on Biological Diversity developed the Manual for Assessing Ecological and Human Health Effects of Genetically Engineered Organisms in order that researchers and producers could determine the “likely consequences of the release of a specific (organism)…familiarity with the range of phenotypic traits expressed (by it) and its parental organisms throughout its life cycle, and the likelihood of local and long distance dispersal and consequent ecosystems (it) may be able to access” (Scientists Working Group on Biosafety). The flowchart for assessing the possible effects of the release of genetically engineered organisms developed by the Working Group is shown below. The above framework was developed with the view of assessing the possible effects of genetically engineered microorganisms in the natural environment. It aims to assess mechanisms such as the following “Gene flow – as genes can be transferred unintentionally to populations of the same or different species; (it) can cause unintended and possibly adverse phenotypic change. Second-site change – unintended genomic changes can occur as a consequence to genetic engineering…like the production of new toxins that may be toxic or allergenic, or may disrupt or alter the metabolic pathways that make the organism useful Possible harmful effects of the organism Other effects on other organisms” (Scientists Working Group on Biosafety 16-18). The World Conservation Union (IUCN) summarizes the need for testing in the 2004 background paper on issues relating to biosafety by stating that there is increased activity regarding biosafety issues, even with the controversy surrounding it and “Proponents identify possible benefits of GMOs that are enormous, including possibilities such as hunger alleviation, and universally available medical care, within our lifetimes. Counter-arguments identify a level of possible risks well beyond anything that has ever been deemed ‘acceptable’ in the past. It is essential that decision-makers and others seeking to progress beyond the current stalemate demonstrate a strong commitment to the position that, in the absence of sufficient scientific certainty surrounding the commercial application of modern biotechnology, preventive and precautionary measures based on risk assessment and management are called for at all international and national levels” (IUCN 40). Work Cited Alun J. and Morgan, W. Genetic Engineering of Microorganisms: Free Release Into the Environment. n.d. Web. 1 December 2012. Biello, David. “Genetically Engineered Stomach Microbe Converts Seaweed into Ethanol”. Scientific American. 19 January 2012. Web. 1 December 2012. Bokinsky, Gregory, Peralta-Yahya, Pamela P., George, Anthe, Holmes, Bradley M., Steen, Eric J., Dietrich, Jeffrey, Soon Lee, Taek, Tullman-Ercek, Danielle, Voigt, Christopher A., Simmons, Blake A. and Keasling, Jay D. “Synthesis of three advanced biofuels from ionic liquid-pretreated switchgrass using engineered Escherichia coli”. Proceedings of the National Academy of Sciences. 2011. Web. 1 December 2012. Colwell, Rita R. Release of Genetically Engineered Microorganisms into the Environment. MIRCEN Journal 1986, Issue no. 2. pp 41-49. 1986. Web. 1 December 2012. Coren, Michael J. “Biodegradable Plastic Manufactured from Air and Bacteria”. Scientific American. 5 November 2012. Web. Hogg, Stuart. Essential Microbiology. West Sussex, England: John Wiley & Sons, Ltd. 2005.Print. Klingmuller, Walter. “Genetic Engineering for Practical Application”. Symposium on Gene Engineering, Part 2, Genetics of Plasmids. Moscow. 1978. Web. 1 December 2012. Krieger, Kim. “Genetically Engineered Bacteria Could Help Fight Climate Change”. Science Mag. 26 February 2012. Web. 1 December 2012. Lada, Aaron. “Genetically Engineered Microorganism: Can the Smallest Creatures Solve Our Biggest Problems?” Ecohearth. 14 July 2011. Web. 1 December 2012. Locke, Susannah F. “10 Ways Genetically Engineered Microbes Could Help Humanity”. Discovery Magazine. August 2008. Web. ___. “Genetically Engineered Bacteria are Sweet Success Against Inflammatory Bowel Disease”. Science Daily. 21 August 2009. Web. 1 December 2012. ___. “Genetically Engineered Bacteria to Measure Water Quality”. Clean Technica. 2009. Web. 1 December 2012. ___. Recombinant DNA Technology in the Synthesis of Human Insulin translated in Romanian by Alexander Ovsov. n.d.Web. 1 December 2012. ___. “Researchers Synchronize Blinking ‘Genetic Clocks’ Using Bacteria”. Science Daily ENVIS Centre Newsletter 8-1. 2010. Web. 1 December 2012. ___. “What are some important uses of genetic engineering?” Discovery Channel. n.d. Web. 1 December 2012. Scientists’ Working Group on Biosafety. Manual for Assessing Ecological and Human Health Effects of Genetically Engineered Organisms. The Edmonds Institute. 1998. Web. 1 December 2012. The National Research Council. Biological Confinement of Genetically Engineered Organisms. Washington DC: National Academy of Sciences. 2004. Web. 1 December 2012. Venkov, Vassili V. “Stress-Induced Evolution And The Biosafety Of Genetically Modified Microorganisms Released Into The Environment”. J. Bioci Vol 26 No 5 pp 667-683, Indian Academy of Sciences. December 2001. Web. 1 December 2012. Young, Tomme. Genetically Modified Organisms and Biosafety. IUCN Environmental Law Centre. August 2004. Web. 1 December 2012. Read More