BIOTECH 3
Remediation is the removal of pollution or contaminants from land (including sediments in waterways) for the general protection of the environment or, quite commonly, from a brownfield site so that it can be reused. The reuse of brownfield sites is part of the urban consolidation movement and allows the regeneration of decaying former industrial areas, sometimes for industry, but often for high density housing, particulalry in areas of scenic beauty (along Harbours and rivers) and close to the CBD of a city or major transport infrastructure such as railway stations.
Remediation is generally subject to an array of legislation, and is based on assessments of health and ecological risks where there are no legislated standards or where standards are advisory (often called preliminary remediation goals (PRG)s).
Remediation in terms of new media, is the representation of one medium in another. (Jay David Bolter and Richard Grusin 1999).
Remediation standards In the USA the most comprehensive set of PRG's is from the EPA Region 9, although the Canadian EPA also has a comprehensive spreadsheet of PRG's. There is also a set of standard used in Europe commonly called the Dutch standards. The EU is rapidly moving towards European wide standards, although most of the industrialised nations in Europe have their own standards at present
Site assessment Once a site is suspected of being seriously contaminated there is a need to assess it. The historical use of the site and the materials used and produced on site will guide the assessment strategy and nature of sampling and chemical testing to be done. Often nearby sites owned by the same company or which are nearby and have been reclaimed, levelled or filled are also contaminated even where the current land use seems innocuous. For example, the car park may have been levelled by using contaminated waste in the fill. It is also important to consider off site contamination or nearby sites often through decades of emissions to soil, water, and air. Ceiling dust, topsoil, surface and groundwater of nearby properties should be tested both before and after the remediation. This is a controversial step as:
No one wants to have to pay for the clean up of the site; If nearby properties are found to be contaminated it may have to be noted on their property title, potentially affecting saleability or value; No one wants to pay for the cost of assessment. Often corporations which do voluntary testing of their sites are protected from the reports to environmental agencies becoming public under Freedom of Information Acts, however a Freedom Of Information inquiry will often produce other documents that are not protected or will produce references to the reports.
Funding remediation In the US there has been a mechanism for taxing polluting industries to form a Superfund to remediate abandoned sites, or to litigate to force corporations to remediate their contaminated sites. Other countries have other mechanisms and commonly sites are rezoned to "higher" uses such as high density housing, to give the land a higher value so that after deducting clean up costs there is still an incentive for a developer to purchase the land, clean it up, redevelop it and sell it on, often as apartments (home units).
Remediation technologies Remediation technologies are many and varied. The best source of information is probably http://www.clu-in.org/
Some technologies are controversial, particularly anything involving relative low temperature incineration because of the risks of dioxins released in the atmosphere through the exhaust gases. For this reason remediation proponents often use terminolgy like thermal oxidiser and direct thermal desorption to minimise the risk of the community thinking about incineration risks. However, controlled, high temperature incineration with filtering of exhaust gases should not pose any risks.
The treatment of environmental problems through biological means is known as bioremediation and the specific use of plants is known as phytoremediation.
Community consultation and information In preparation for any significant remediation there should be extensive community consultation. The proponent should both present information to and seek information from the community. The proponent needs to know about "sensitive" (future) uses like childcare, schools, hospitals, and playgrounds as well as community concerns and interests information. Consultation should be open, on a group basis so that each member of the community is informed about issues they may not have individually thought about. An independent chairperson acceptable to both the proponent and the community should be engaged (at proponent expense if a fee is required). Minutes of meetings including questions asked and the answers to them and copies of presentations by the proponent should be available both on the internet and at a local library (even a school library) or community centre.
Incremental health risk Incremental Health Risk is the increased risk that a receptor (normally a human being living nearby) will face from (the lack of) a remediation project. The use of incremental health risk is based on cancer and non-cancer effects such as reproductive abnormalities and often involves value judgements about the acceptable projected rate of increase in cancer. In some jursdictions this is 1 in a million, but in other jurisdictions it is 1 in 100,000. A relatively small incremental health risk from a single project is not of much comfort if the area already has a relatively high health risk from other operations like incinerators or other emissions, or if there are other projects at the same time causing a greater cumulative risk or an unacceptably high total risk. An analogy often used by remediators is to compare the risk of the remediation on nearby residents to the risks of death through car accidents or tobacco smoking.
Emissions standards Standards are set for the levels of dust, noise, odour, emissions to air and groundwater, and discharge to sewer or waterways of all chemicals of concern or chemicals likely to be produced during the remediation by processing of the contaminants. These are compared against both natural background levels in the area and standards for areas zoned as nearby areas are zoned and against standards used in other recent remediations. Just because the emission is emanating from an area zoned industrial doesn't mean that in a nearby residential area there should be permitted any exceedences of the appropriate residential standards.
Monitoring for compliance against each standards is critical to ensure that exceedences are detected and reported both to authorities and the local community.
Enforcement is necessary to ensure that continued or significant breeches result in fines or even a jail sentence for the remediator.
Penalties must be significant as otherwise fines are treated as a normal expense of doing business. It must be cheaper to comply than have continuous breeeches.
Transport and emergency safety assessment Assessment should be made of the risks of operations, transporting contaminated material, disposal of waste which may be contaminated including workers clothes, and a formal emergency response plan should be developed. Every worker and visitor entering the site should have a safety induction tailored to their involvement with the site.
Impacts of funding remediation The rezoning is often resisted by local communities and local government because of the adverse impacts on the local amenity of the remediation and the new development. The main impacts during remediation are noise, dust, odour and incremental health risk. Then there is the noise dust and traffic of developments. Then there is the impact on local traffic, schools, playing fields, and other public facilities of the often vastly increased local population.
Example of a major remediation project For an example of a complete rezoning by a state government over the opposition of local government and local communities of former chemical plants to fund remediation to allow for redevelopment for high density residential, retail and office development in Australia see http://rhodesnsw.org
In this case the proposed rezoning, remediation and redevelopment has a wealth of material available through the internet from:
list of sources of publicly available material, most accessible through the internet and from http://rhodesnsw.org: Numerous investigations and reports by Australian and International consultants For the former Union Carbide site, a previous remediation by excavation and containment in a clay capped sarcophagus, separated from the Bay by a bentonite wall. A Parliamentary Inquiry by the Upper House of the Parliament of New South Wales, a state of Australia; Two Commissions of Inquiry, one for each of the major dioxin contaminated sites, both contaminated by the operations of Union Carbide; Resolutions by the relevant local government bodies (originally Concord council and after the Municipality of Concord was merged with Drummoyne Council to form the City of Canada Bay, by that Council); Campaigns by local residents' groups, Greenpeace Australia, Nature Conservation Council of NSW, and Inner West (of Sydney branch of the) Greens published submissions by Planning NSW and Environmental Protection Agency of NSW; Comprehensive Environmental Impact studies published in digital format and available on CD from Planning NSW. This rezoning, remediation and redevelopment of land contaminated by Union Carbide, ICI and others also involves the remediation of a strip of dioxin contaminated sediments in Homebush Bay, New South Wales. The Homebush Bay area was home to the main events of the Sydney 2000 Summer Olympics. The sediments were dealt with in the Commission of Inquiry into the Lednez site formerly owned by Union Carbide, but not to the satisfaction of local community activists.
The remediation of Homebush Bay is important because of its impact on the food chain which extends through benthos not only to local protected and threatened species of birds, but also to JAMBA and CAMBA protected species and species which use other RAMSAR protected wetlands. Ultimately human health is impacted through the food chain. Homebush Bay has a complete fishing ban, there is a commercial fin fishing ban west of the Gladesville Bridge, and based on submissions of the remediator and NSW Waterways and EPA the complete fishing ban ought be extended to the whole of the Parramatta River west of Homebush Bay and at least as far East as the Ryde Traffic Bridge.
Phytoremediation is the technical term used to describe the treatment of environmental problems through the use of plants.
Certain plants are able to extract hazardous substances such as arsenic, lead and uranium from soil and water. One example is alpine pennycress, a plant which naturally accumulates high levels of cadmium and zinc from the environment. Alpine pennycress is therefore known as a hyperaccumulator of these metals, which in unnaturally high levels would be poisionous to many plants. Another example of a hyperaccumulator is the brake fern. This fern extracts arsenic from the soil at a much greater rate than other plants.
This has been done successfully in clinical trials, particularly in the case of Ashanti DeSilva, a girl who had a defective gene that was responsible for the immune system enzyme ADA. Thus she was prone to infections. Scientists took out her white blood cells and used a delivery system to inject a functional ADA gene into the cells. These were injected back into Ashanti's arm. a, f. Now she takes only a small "backup" dose of what would have been a battery of preventive medicines for maintaining her healthy state.
This arsenic is stored in the fern's leaves at as much as 200 times that present in the soil, thus enabling effective and practical clean-up programs. Sunflowers were also used to clean up uranium near Chernobyl.
Breeding programs and genetic engineering are powerful methods for enhancing natural tendencies of plant, or for introducing these tendencies into alternative types of plant which might be more suitable for the environmental conditions.
The range of biological treatments for environmental problems, as described by the term phytoremediation, actually consists of several specific processes:
Phytoextraction - Uptake of substances from the environment, with storage in the plant (phytoaccumulation). Phytostabilisation - Reducing the movement or transfer of substances in the environment. For example, limiting the leaching of substances contaminating soil. Phytostimulation - Enhancement of microbial activity for the degradation of contaminants, typically around plant roots. Phytotransformation - Uptake of substances from the environment, with degradation occurring within the plant (phytodegradation). Phytovolatilization - Removal of substances from the soil or water with release into the air, possibly after degradation. Rhizofiltration - The removal of toxic metals from ground water.
Bioleaching is the extraction of specific metals from their ores through the use of bacteria.
Bioleaching is a new technique used by the mining industry to extract minerals such as gold and copper from their ores. Traditional extractions involve many expensive steps such as roasting and smelting, which requires sufficient concentrations of elements in ores. Low concentrations are not a problem for bacteria because they simply ignore the waste which surrounds the metals, attaining extraction yields of over 90% in some cases. These microorganisms actually gain energy by breaking down minerals into their constituent elements. The company simply collects the ions out of solution after the bacteria have finished.
Some advantages associated with bioleaching are:
economical: bioleaching is generally simpler and therefore cheaper to operate and maintain than traditional processes, since fewer specialists are needed to operate complex chemical plants. environmental: The process is more environmentally friendly than traditional extraction methods. For the company this can translate into profit, since the necessary limiting of sulfur dioxide emissions during smelting is expensive. Less landscape damage occurs, since the bacteria involved grow naturally, and the mine and surrounding area can be left relatively untouched. As the bacteria breed in the conditions of the mine, they are easily cultivated and recycled. Some disadvantages associated with bioleaching are:
not economical: the bacterial leaching process is very slow compared to smelting. This brings in less profit as well as introducing a significant delay in cash flow for new plants. not environmental: Toxic chemicals are sometimes produced in the process. Sulfuric acid and H+ ions formed can leak into the ground and surface water turning it acidic, causing environmental damage. Heavy ions such as iron, zinc, and arsenic leak during acid mine drainage. When the pH of this solution rises, as a result of dilution by fresh water, these ions precipitate, forming "Yellow Boy" pollution. For these reasons, setup of bioleaching must be carefully planned, since the process can lead to biosafety failure. f, i, a. Currently it is more economical to smelt copper ore rather than to use bioleaching, since the concentration of copper in its ore is generally quite high. The profit obtained from the speed and yield of smelting justifies its cost. However, the concentration of gold in its ore is generally very low. The cheaper cost of bacterial leaching in this case outweighs the time it takes to extract the metal.
Bacteria (singular, bacterium) are a major group of living organisms. They are microscopic and mostly unicellular, with a relatively simple cell structure lacking a cell nucleus, cytoskeleton, and organelles such as mitochondria and chloroplasts. Such organisms are called prokaryotes, in contrast to organisms with more complex cells, called eukaryotes. The term bacteria has variously applied to all prokaryotes or to a major group of them, depending on ideas about their relationships.
abundant of all organisms. They are ubiquitous in soil, water, and as symbionts of other organisms. Many pathogens, including those responsible for many if not most non-hereditary diseases, are bacteria. Most are minute, usually only 0.5-5.0 μm in size, though one type may reach 0.3 mm in diameter (Thiomargarita). They generally have cell walls, like plant and fungal cells, but with a very different composition (peptidoglycans). Many move around using flagella, which are different in structure from the flagella of other groups.
The first bacteria were observed by Antony van Leeuwenhoek in 1683 using a single-lens microscope of his own design. The name bacterium was introduced much later, by Ehrenberg in 1828, derived from the Greek word βακτηριον meaning "small stick". Louis Pasteur (1822-1895) and Robert Koch (1843-1910) described the role of bacteria as conveyors and causes of disease or pathogens.
Originally the bacteria were considered microscopic fungi (called Schizomycetes), except for the photosynthetic cyanobacteria, which were considered a group of algae (called Cyanophyta or blue-green algae). It was only with the study of detailed cell structure that it was realized they formed a fundamental group, separate from the other organisms. In 1956 Copeland gave them their own kingdom Mychota, later renamed Monera, Prokaryota, or Bacteria. During the 1960s the concept was refined and bacteria (now including cyanobacteria) were recognized as one of two major divisions of the living world, together with the eukaryotes. Eukaryotes were generally believed to have evolved from bacteria, later from assemblies of bacteria.
The advent of molecular systematics challenged this view. In 1977, Woese divided the prokaryotes into two groups based on 16S rRNA sequences, called the kingdoms Eubacteria and Archaebacteria. He argued that each of these and the eukaryotes all evolved separately and in 1990 emphasized this by promoting them to domains, which were renamed the Bacteria, Archaea, and Eucarya. This redefinition has generally been accepted by molecular biologists but criticized by some others, who maintain that he over-emphasized a few genetic differences and that both archaebacteria and eukaryotes probably developed from within the eubacteria.
Reproduction Bacteria reproduce only asexually, not sexually. Specifically they reproduce by binary fission, or simple cell division. During this process, one cell divides into two daughter cells with the development of a transverse cell wall.
However, independent of sexual reproduction, genetic variations can occur within individual cells through recombinant events such as mutation (random genetic change within a cell's own genetic code). Similar to more complex organisms, bacteria also have mechanisms for exchanging genetic material. Although not equivalent to sexual reproduction, the end result is that a bacterium contains a combination of traits from two different parental cells. Three different modes of exchange have thus far been identified in bacteria:
transformation (the transfer of naked DNA from one bacterial cell to another in solution, this can include dead bacteria), transduction (the transfer of viral, bacterial, or both bacterial and viral DNA from one cell to another via bacteriophage) and; bacterial conjugation (the transfer of DNA from one bacterial cell to another via a special protein structure called a conjugation pilus). Bacteria, having acquired DNA from any of these events, can then undergo fission and pass the recombined genome to new progeny cells. Many bacteria harbor plasmids that contain extrachromosomal DNA. Under favourable conditions, bacteria may form aggregates visible to the naked eye, such as bacterial mats.
Researchers today are using the same method to find cures for cancers, AIDS, and cystic fibrosis. DNA Vaccines and Edible Vaccines are two types of vaccines biotechnologists are trying to develop. Both aim to produce vaccines that are cheaper and more accessible. DNA vaccines are composed of genes that code for inactive virus parts. When injected directly into our bodies, we will produce these inactive virus parts that may cause our immune system to recognize the whole virus when it infects us later. h, a, k, d, k. Thus our immune system will be ready to defend us. On the other hand, in edible vaccines these genes are packaged into food, such as bananas, so that they will be in a form readily distributed and accepted by the people. No more injections!
Metabolisms Bacteria show a wide variety of different metabolisms. Heterotrophs depend on an organic source of carbon, while autotrophs are able to synthesize organic compounds from carbon dioxide and water. Autotrophs that obtain energy by oxidizing chemical compounds are called chemotrophs, and those that obtain their energy from light, via photosynthesis, are called phototrophs. There are many variations on this terminology such as chemoautotrophs and photosynthetic autotrophs and so on. In addition, bacteria are distinguished based on the source of reducing equivalents they are using. Those using inorganic compounds (e. g. water, hydrogen, sulfide or ammonia) for this purpose are called lithotrophs and others needing organic compounds (e. g. sugars or organic acids) and are called organotrophs. The metabolic modes of energy metabolism (phototrophy or chemotrophy), reducing equivalent sources (lithotrophy or organotrophy) and carbon sources (autotrophy or heterotrophy) can be combined differently in any single microorganism, and even shifting between different modes frequently occurs in many species.
The photolithoautotrophs include the cyanobacteria, which are some of the oldest organisms known from the fossil record and probably played an important role in creating the Earth's oxygen atmosphere. They apparently pioneered the use of water as (lithotrophic) electron source and were the first to use the photosynthetic water splitting apparatus. Other photosynthetic bacteria use different electron sources and therefore do not produce oxygen. These anoxygenic phototrophs fall into four phylogenetic groups: the green sulfur bacteria, green non-sulfur bacteria, purple bacteria, and heliobacteria.
Other nutritional requirements include nitrogen, sulfur, phosphorus, vitamins and metallic elements such as sodium, potassium, calcium, magnesium, manganese, iron, zinc, cobalt, copper and nickel for normal growth. For some species, additional trace elements such as selenium, tungsten, vanadium or boron are needed.
Based on their response to oxygen, most bacteria can be placed into one of three groups: Some bacteria can grow only in the presence of oxygen and are called aerobes; others can grow only in the absence of oxygen and are called anaerobes; and some can grow in the presence or absence of oxygen and are called facultative anaerobes. Bacteria that do not utilize oxygen for respiration but still grow in its presence are called aerotolerant. Bacteria also thrive in environments that are considered extreme for mankind. These organisms are called extremophiles. Some bacteria inhabit hot springs and are called thermophiles; others inhabit highly saltine lakes and are called halophiles; yet others inhabit acidic or alkaline environments and are called acidophiles and alkaliphiles, respectively; and still others inhabit alpine glaciers and are called psychrophiles.
Movement Motile bacteria can move about, either using flagella, bacterial gliding, or changes of buoyancy. A unique group of bacteria, the spirochaetes, have structures similar to flagella, called axial filaments, between two membranes in the periplasmic space. They have a distinctive helical body which twists about as it moves.
Bacterial flagella are arranged in many different ways. Bacteria can have a single polar flagellum at one end of a cell, or they can have clusters of many flagella at one end. Peritrichous bacteria have flagella scattered all over the cell. Many bacteria (such as e.coli) have two distinct modes of movement: forward movement (swimming) and tumbling. The tumbling allows them to reorient and introduces an important element of randomness in their forward movement. (see external links below for link to videos).
Motile bacteria are attracted or repelled by certain stimuli, behaviors called taxes - for instance, chemotaxis, phototaxis, mechanotaxis and magnetotaxis (Italian) (http://it.wikipedia.org/wiki/Batteri_magnetotattici). In one peculiar group, the myxobacteria, individual bacteria attract to form swarms and may differentiate to form fruiting bodies.
Bacteria come in a variety of different shapes. Most are rod-shaped, sphere-shaped, or helix-shaped; these are respectively referred to as bacilli, cocci, and spirillum. An additional group, vibrios, are comma-shaped. Shape is no longer considered a defining factor in the classification of bacteria, but many genera are named for their shape (e.g. Bacillus, Streptococcus, Staphylococcus) and it is an important part in their identification.
Another important tool is Gram staining, named after Hans Christian Gram who developed the technique. This separates bacteria into two groups, based on the composition of their cell wall. The first formal grouping of bacteria into phyla was based largely on this test:
Gracilicutes - bacteria with a second cell membrane containing lipids, giving them Gram-negative stains Firmicutes - bacteria with a single membrane and thick peptidoglycan wall, giving them Gram-positive stains Mollicutes - bacteria with no second membrane or wall, giving them Gram-negative stains The archeabacteria were originally included as the Mendosicutes. As given, these phyla are no longer believed to represent monophyletic groups. The Gracilicutes have been divided into many different phyla. Most gram-positive bacteria are placed in the phyla Firmicutes and Actinobacteria, which are closely related. However, the Firmicutes have been redefined to include the mycoplasmas (Mollicutes) and certain Gram-negative bacteria.
Benefits and dangers Bacteria are both harmful and useful to the environment, and animals, including humans. The role of bacteria in disease and infection is important. Some bacteria act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, foodborne illness and tuberculosis. Sepsis, a systemic infectious syndrome characterized by shock and massive vasodilation, or localized infection, can be caused by bacteria such as streptococcus, staphylococcus, or many gram-negative bacteria. Some bacterial infections can spread throughout the host's body and become systemic. In plants, bacteria cause leaf spot, fireblight, and wilts. The mode of infection includes contact, air, food, water, and insect-borne microorganisms. The hosts infected with the pathogens may be treated with antibiotics, which can be classified as bacteriocidal and bacteriostatic, which at concentrations that can be reached in bodily fluids either kill bacteria or hamper their growth, respectively. Antiseptic measures may be taken to prevent infection by bacteria, for example, prior to cutting the skin during surgery or swabbing skin with alcohol when piercing the skin with the needle of a syringe. Sterilization of surgical and dental instruments is done to make them sterile or pathogen-free to prevent contamination and infection by bacteria. Sanitizers and disinfectants are used to kill bacteria or other pathogens to prevent contamination and risk of infection.
In soil, microorganisms help in the transformation of nitrogen to ammonia with enzymes secreted by these microbes, which reside in the rhizosphere (a zone that includes the root surface and the soil that adheres to the root after gentle shaking). Some bacteria are able to use molecular nitrogen as their source of nitrogen, converting it to nitrogenous compounds, a process known as nitrogen fixation. Many other bacteria are found as symbionts in humans and other organisms. For example, their presence in the large intestine can help prevent the growth of potentially harmful microbes.
The ability of bacteria to degrade a variety of organic compounds is remarkable. Highly specialized groups of microorganisms play important roles in the mineralization of specific classes of organic compounds. For example, the decomposition of cellulose, which is one of the most abundant constituents of plant tissues, is mainly brought about by aerobic bacteria that belong to the genus Cytophaga.
Bacteria, often in combination with yeasts and molds, are used in the preparation of fermented foods such as cheese, pickles, soy sauce, sauerkraut, vinegar, wine, and yoghurt. Using biotechnology techniques, bacteria can be bioengineered for the production of therapeutic drugs, such as insulin, or for the bioremediation of toxic wastes.
Miscellaneous In terms of evolution, bacteria are thought to be very old organisms, appearing about 3.7 billion years ago.
Two organelles, mitochondria and chloroplasts, are generally believed to have been derived from endosymbiotic bacteria.
Microorganisms are widely distributed and are most abundant where they have food, moisture, and the right temperature for their multiplication and growth. Bacteria can be carried by air currents from one place to another. The human body is home to billions of microorganisms; they can be found on skin surfaces, in the intestinal tract, in the mouth, nose, and other body openings. They are in the air one breathes, the water one drinks, and the food one eats.
A micro-organism or microbe is an organism that is so small that it is invisible to the naked eye. The term is synonymous by usage to single-celled organism, and unicellular organism, even though some consist of more than one cell, some unicellular protists are visible to the naked eye, and some colonial species are microscopic. All unicellular organisms are able to reproduce themselves without help of other organisms, as opposed to viruses.
Micro-organisms may be found almost anywhere in the taxonomic structure. Bacteria and archaea are always or almost always microscopic, as are most protists. Even some fungi, a primarily macroscopic taxon, are micro-organisms.
Micro-organisms are found everywhere in nature, owing to the existence of extremophiles, micro-organisms that have adapted to generally hostile environments. Extremophiles may be found in environments such as the poles, deserts, geysers, just beneath the surface of rocks, and the bottom of the deep sea. Some are known to survive prolonged time in vacuum, or to be unusually resistant to radiation.
Micro-organisms can be helpful in recycling other organisms' remains and waste products, or when employed in biotechnology, e.g., for brewing and bakery. They can also be harmful as pathogens when, as parasites, causing infections. Micro-organisms were probably the first form of life that appeared on earth. Today they have an important place in all ecosystems and in most higher multicellular organisms. For mankind they are important for participating in driving the earths main element cycles, and for the creation of certain types of food, medical substances and biological weapons.
In the future, non-allergenic chocolates and other foodstuffs can be produced. Food can be genetically engineered to remove its protein component that causes allergies. This would relieve a great number of people who are now on restricted diets because of food allergy. Biotechnology offers us a wide range of products that will make our lives easier: by protecting us from disease, by finding new ways of treatment, by helping increase the production of food in quality and quantity, and by maintaining the environment. This is the thrust of The National Institutes of Molecular Biology and Biotechnology. Any new technology must not only be beneficial to the people, but must also follow the rules of sustainable development. l, a, f, b, d. As recipients of this technology, we must be open to all possibilities and support the work of Philippine researchers, because biotechnology is truly a "human technology".
Biotechnology in one form or another has flourished since prehistoric times. When the first human beings realized that they could plant their own crops and breed their own animals, they learned to use biotechnology. The discovery that fruit juices fermented into wine, or that milk could be converted into cheese or yogurt, or that beer could be made by fermenting solutions of malt and hops began the study of biotechnology. When the first bakers found that they could make a soft, spongy bread rather than a firm, thin cracker, they were acting as fledgling biotechnologists. The first animal breeders, realizing that different physical traits could be either magnified or lost by mating appropriate pairs of animals, engaged in the manipulations of biotechnology.
What then is biotechnology? The term brings to mind many different things. Some think of developing new types of animals. Others dream of almost unlimited sources of human therapeutic drugs. Still others envision the possibility of growing crops that are more nutritious and naturally pest-resistant to feed a rapidly growing world population. This question elicits almost as many first-thought responses as there are people to whom the question can be posed.
In its purest form, the term "biotechnology" refers to the use of living organisms or their products to modify human health and the human environment. Prehistoric biotechnologists did this as they used yeast cells to raise bread dough and to ferment alcoholic beverages, and bacterial cells to make cheeses and yogurts and as they bred their strong, productive animals to make even stronger and more productive offspring.
Biotechnology is a broad term that applies to all practical uses of living organisms—anything from microorganisms used in the fermentation of beer to the most sophisticated application of gene therapy. The term covers applications that are old and new, familiar and strange, sophisticated and simple. Defined in this way, the term is almost too broad to be useful. One way of thinking about biotechnology is to consider two categories of activities: those that are traditional and familiar and those that are relatively new. Within each category can be found technologies that are genetic—that involve modifications of traits passed down from one generation to the next—and technologies that are not.
Although there are interesting issues connected with a number of biotechnologies—both old and new—most of UCS's work focuses on genetic engineering, a new genetic biotechnology.
Traditional Biotechnologies
A prime example of traditional genetic biotechnologies is selective breeding of plants and animals. The rudiments of selecting plants and animals with desirable traits and breeding them under controlled conditions probably go back to the dawn of civilization, but the expansion of knowledge about genetics and biology in this century has developed selective breeding into a powerful and sophisticated technology. New molecular approaches like marker-assisted breeding (which enhances traditional breeding through knowledge of which cultivars or breeds carry which trait) promise to enhance these approaches even further. Traditional breeding technologies have been immensely successful, and indeed are largely responsible for the high yields associated with contemporary agriculture. These technologies should not be considered passé or out of date. For multigene traits like intrinsic yield and drought resistance, they surpass genetic engineering. This is because selective breeding operates on whole organisms—complete sets of coordinated genes—while genetic engineering is restricted to three or four gene transfers with little control over where the new genes are inserted. For the most important agronomic traits, traditional breeding remains the technology of choice.
Other traditional nongenetic biotechnologies include the fermentation of microorganisms to produce wine, beer, and cheese. Industry also uses microorganisms to produce various products such as enzymes for use in laundry detergents. In an effort to find microorganisms that produce large amounts of enzymes, scientists sometimes treat a batch of organisms with radiation or chemicals to randomly produce genetic alternations. The process, called mutagenesis, produces numerous genetic changes in the bacteria, among which might be a few that produce more of the desired product.
New Biotechnologies
Many new biotechnologies do not involve modifications of traits passed on to the next generation. A good example is monoclonal antibodies (highly specific preparations of antibodies that bind to a single site on a protein), which have many diagnostic applications, including home pregnancy testing kits. Many biotechnology companies are engaged in these sophisticated, but noncontroversial, technologies. By contrast, mammalian cloning is a new biotechnology that does not involve gene modification, but is nevertheless highly controversial. Cloning reproduces adult mammals by transplanting a nucleus from adult cells into an egg from which the nucleus has been removed and allowing the egg to develop in a surrogate manner. The resulting individuals are as similar to the adults from which the nuclei were taken as identical twins are to one another. Although this procedure has profound implications for human reproduction, it does not modify specific traits of an individual, but rather transfers a whole nucleus containing a complete set of genetic information.
The new technology that can affect future generations is genetic engineering, a technology based on the artificial manipulation and transfer of genetic material. This technology can move genes and the traits they dictate across natural boundaries—from one type of plant to another, from one type of animal to another, and even from a plant to an animal or an animal to a plant. Cells modified by these techniques pass the new genes and traits on to their offspring. Genetic engineering can apply to any kind of living organism from microorganisms to humans.
Genetic engineering can be applied to humans to replace or supplement defective genes. Where engineering is intended to cure disease, it is called gene therapy. Potential applications that are not related to disease, such as the modification of traits like height, are sometimes called genetic enhancement. Currently, most genetic engineering of humans is done on nonreproductive or somatic cells, like those from bone marrow. The effects of this somatic cell gene therapy are confined to the treated individual. By contrast, germ line gene therapy would modify reproductive cells, so that the modification could be passed on to future generations.
Biotechnology; what is it? Biotechnology is the use of organisms to perform useful chemical reactions for industrial purposes. Brewing, in which yeast makes alcohol and carbon dioxide from sugar, is probably the easiest example which springs to mind. Modern biotechnology frequently involves genetic engineering of those organisms to improve an industrial process. The study of biotechnology at University involves study of microbiology, biochemistry and genetics. e, h, d, h, d. Knowledge of all three subjects is crucial in an area where microorganisms are frequently being genetically engineered to perform novel or enhanced biochemical reactions.
'Biotechnology' is a term used to cover the use of living things in industry, technology, medicine or agriculture. Biotechnology is used in the production of foods and medicines, the removal of wastes and the creation of renewable energy sources.
Simply defined, biotechnology is any technology that relies on living organisms or biological systems. By this definition, human beings have been using biotechnology for thousands of years to produce food products, textiles and other necessary items. Several familiar items -- including yeast-rising bread, yogurt, cheese, wine, beer and vinegar -- are all produced with the help of cultured microorganisms.
In recent years, however, the term "biotechnology" has come to mean the use of genetic engineering and its associated techniques. This more common definition is found in a variety of applications, from medicine to agriculture.
Amgen manufactures therapeutics based on molecules that already exist in the human body. Biotechnology is the process by which these natural components of the body are produced in sufficient quantities to use therapeutically.
Pharmaceuticals produced in this way are virtually identical to naturally occurring materials. These products are usually proteins, and have a very specific physiological role. As a result, they may have fewer undesirable side effects associated with them. By contrast, traditional drugs are produced through synthetic organic chemistry, and are often less specific in their activity. Numerous side effects can result, limiting the usefulness of these drugs.
In creating our protein products, Amgen scientists often use the techniques of genetic engineering. Starting with bacteria, yeast, or cultured animal cells, they introduce the information needed to produce a human protein with therapeutic potential. Once engineered, these cells can be grown in large quantities, often using the time-honored technique of fermentation.
During fermentation, single celled organisms such as yeasts and bacteria grow on sugars and starches. Their growth produces alcohol, carbon dioxide and other by-products. (The bubbles in alcohol in beer are a result of this process, as are the holes in bread and some cheeses.) While fermenting, engineered cells produce large quantities of another important product: the desired human protein. Depending how the cell was engineered, this protein is found either inside the cells or in the surrounding medium.
Agricultural biotechnology involves scientific methods that create, improve or modify plants and animals. This technology allows scientists to move desirable genes from one plant to another or from one animal to another. Through agricultural biotechnology, researchers transfer desirable genes (insect resistance, large muscle mass, better flavor, longer shelf life) into various plants and/or animals.
Traditional animal breeding involves selecting the best parent animals to produce desirable offspring. Animal reproduction through biotechnology includes techniques such as selecting a cattleman’s best bull and replicating it through cloning.
Traditional plant breeding involves transferring pollen containing a desired gene from one crop to another. Breeding plants through biotechnology involves adding a pest-resistant corn gene to another corn variety or to a soybean or wheat variety.
Agricultural biotechnology is the science of transferring beneficial genetic traits to improve the world’s supply of food and fiber.
Break biotechnology into its root words and you have bio — the use of biological processes; and technology — to solve problems or make useful products.
Using biological processes is hardly a new undertaking. We began growing crops and raising animals 10,000 years ago to provide a stable supply of food and clothing. We have used the biological processes of microorganisms for 6,000 years to make useful food products, such as bread and cheese, and to preserve dairy products. Why is biotechnology suddenly receiving so much attention?
During the 1960s and '70s our understanding of biology reached a point where we could begin to use the smallest parts of organisms—their cells and biological molecules—in addition to using whole organisms.
A more appropriate definition in the new sense of the word is this:
"New" Biotechnology — the use of cellular and biomolecular processes to solve problems or make products.
We can get a better handle on the meaning of the word biotechnology by simply changing the singular noun to its plural form, biotechnologies. Biotechnology is a collection of technologies that capitalize on the attributes of cells, such as their manufacturing capabilities, and put biological molecules, such as DNA and proteins, to work for us.
Cells and Biological Molecules
Cells are the basic building blocks of all living things. The simplest living things, such as yeast, consist of a single, self-sufficient cell. Complex creatures more familiar to us, such as plants, animals and humans, are made of many different cell types, each of which performs a very specific task.
In spite of the extraordinary diversity of cell types in living things, what is most striking is their remarkable similarity. This unity of life at the cellular level provides the foundation for biotechnology.
All cells have the same basic design, are made of the same construction materials and operate using essentially the same processes. DNA (deoxyribonucleic acid), the genetic material of almost all living things, directs cell construction and operation, while proteins do all the work. Because DNA contains the information for making proteins, it directs cell processes by determining which proteins are produced and coordinating their activities.
All cells speak the same genetic language. The DNA information manual of one cell can be read and implemented by cells from other living things. Because a genetic instruction to make a certain protein is universally understood by all cells, technologies based on cells and biological molecules give us great flexibility in using nature's diversity.
In addition, cells and biological molecules are extraordinarily specific in their interactions. Because of this specificity, biotechnology's tools and techniques are precise; they are tailored to operate in known, predictable ways. As a result, biotechnology products will solve specific problems, generate gentler or fewer side effects and have fewer unintended consequences. Specific, precise, predictable. Those are the words that best describe today's biotechnology.
Basically bioremediation is using microorganisms to remove pollutants from an environment. At its natural rate this process would be called biodegradation. The name bioremediation accompanies when the human factor, manipulating conditions affecting the rate, enters the picture. It is most often used for the treatment of non-toxic liquid and solid wastes, contaminated ground water, toxic and hazardous wastes and grease decomposition. It is known to be a practical and cost-effective method to remove hydrocarbons from contaminated areas. Altogether, more than 70 microbial genera are known to contain organisms that can degrade petroleum components(8, Congress Report). Since any given oil would have a diversity of compounds, obviously there is a need for the variety. Organic contaminants that make up the oil, provide energy and act as a carbon source. The microorganisms transform contaminants to less harmful compounds through aerobic and anaerobic respiration, fermentation, cometabolism and reductive dehalogenation. The microbes may demobilize the contaminants as well in 3 ways as the National Research Council (page 23) has stated:
Microbial biomass can sorb hydrophobic organic molecules. sufficient biomass grown in the path of contaminant migration could stop or slow contaminant movement. This concept is sometimes called a biocurtain.
Microorganisms can produce reduced or oxidized species that cause metals to precipitate. Fe(OH)3 , FeS precipitates would be certain examples.
Why is biotechnology important? Biotechnology is not a new science, and originated from the day man first brewed beer and baked bread. Traditional uses of biotech will continue and are crucially important to society. However, with the recent advances in DNA sequencing of genomes, particularly the human genome, biotech science is well placed to make rapid advances. The potential of biotechnology to provide new health products, new fuels such as hydrogen, advances in agriculture and management of the environment (eg. oil spill clean-up) is immense but at present only partly tapped. i, f, b, h, b. Biotechnology is well-placed to contribute significantly to future sustainable technology development.
Microorganisms can biodegrade organic compounds that bind with metals and keep the metals in solution. Unbound metals often precipitate and are immobilized.
The National Research Council divides the applications of bioremediation into two broad categories, namely intrinsic and engineered bioremediation. Intrinsic bioremediation is similar to a no-action alternative; however, monitoring and proof that microorganisms act as eliminators of contaminants is necessary. With engineered bioremediation the human factor comes into the picture. As stated in the Congress Report there are three major approaches used for bioremediation of marine oil spills: stimulation of indigenous microorganisms through addition of nutrients(fertilization), introduction of special assemblages of naturally occurring oil degrading microorganisms(seeding) and introduction of genetically engineered microorganisms(GEMs) with special oil degrading properties. Research has shown that in most cases the contaminated area contains enough variety of organisms but does not have the capacity to feed them. Therefore, using seeding methods or introducing GEMs to a site have not been widely used. Most of the experiments were administered on fertilization methods-or nutriation as some call it. After the Exxon Valdez oil spill in Alaska on March 24, 1989 , scientists had a grand opportunity to work on the unknown aspects of this technology. As Pritchard explains it, there were three main criteria in making a fertilizer selection: ease of application potential to retain position on the beaches, nutrient release characteristics and physical durability over time. Basically three modes of application were observed, briquettes, granules and liquid. Of the three, granules seemed to be the most apt method. These fertilizers contained nitrogen as a majority and also some phosphorus. So it was important to reach a level of nutrients without exceeding level of toxicity for certain marine invertebrates to survive. It is important to realize that for each site the best mode of fertilizer application would be different and that it would have to be determined specifically. Therefore, it is not possible to state one fertilizer AS THE ULTIMATE METHOD
No comments:
Post a Comment