An Introduction to Biotechnology

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Abstract

Biotechnology is multidisciplinary field which has major impact on our lives. The technology is known since years which involves working with cells or cell-derived molecules for various applications. It has wide range of uses and is termed “technology of hope” which impact human health, well being of other life forms and our environment. It has revolutionized diagnostics and therapeutics; however, the major challenges to the human beings have been threats posed by deadly virus infections as avian flu, Chikungunya, Ebola, Influenza A, SARS, West Nile, and the latest Zika virus. Personalized medicine is increasingly recognized in healthcare system. In this chapter, the readers would understand the applications of biotechnology in human health care system. It has also impacted the environment which is loaded by toxic compounds due to human industrialization and urbanization. Bioremediation process utilizes use of natural or recombinant organisms for the cleanup of environmental toxic pollutants. The development of insect and pest resistant crops and herbicide tolerant crops has greatly reduced the environmental load of toxic insecticides and pesticides. The increase in crop productivity for solving world food and feed problem is addressed in agricultural biotechnology. The technological advancements have focused on development of alternate, renewable, and sustainable energy sources for production of biofuels. Marine biotechnology explores the products which can be obtained from aquatic organisms. As with every research area, the field of biotechnology is associated with many ethical issues and unseen fears. These are important in defining laws governing the feasibility and approval for the conduct of particular research.

Keywords: Stem Cell Research, Itaconic Acid, Levulinic Acid, Salmon Calcitonin, Agricultural Biotechnology

Introduction

The term “ biotechnology” was coined by a Hungarian engineer Karl Ereky, in 1919, to refer to the science and methods that permit products to be produced from raw materials with the aid of living organisms. Biotechnology is a diverse field which involves either working with living cells or using molecules derived from them for applications oriented toward human welfare using varied types of tools and technologies. It is an amalgamation of biological science with engineering whereby living organisms or cells or parts are used for production of products and services. The main subfields of biotechnology are medical (red) biotechnology, agricultural (green) biotechnology, industrial (white) biotechnology, marine (blue) biotechnology, food biotechnology, and environmental biotechnology (Fig. 1.1 .). In this chapter the readers will understand the potential applications of biotechnology in several fields like production of medicines; diagnostics; therapeutics like monoclonal antibodies, stem cells, and gene therapy; agricultural biotechnology; pollution control ( bioremediation); industrial and marine biotechnology; and biomaterials, as well as the ethical and safety issues associated with some of the products.

Major applications of biotechnology in different areas and some of their important products

The biotechnology came into being centuries ago when plants and animals began to be selectively bred and microorganisms were used to make beer, wine, cheese, and bread. However, the field gradually evolved, and presently it is the use or manipulation of living organisms to produce beneficiary substances which may have medical, agricultural, and/or industrial utilization. Conventional biotechnology is referred to as the technique that makes use of living organism for specific purposes as bread/cheese making, whereas modern biotechnology deals with the technique that makes use of cellular molecules like DNA, monoclonal antibodies, biologics, etc. Before we go into technical advances of DNA and thus recombinant DNA technology, let us have the basic understanding about DNA and its function.

The foundation of biotechnology was laid down after the discovery of structure of DNA in the early 1950s. The hereditary material is deoxyribonucleic acid (DNA) which contains all the information that dictates each and every step of an individual’s life. The DNA consists of deoxyribose sugar, phosphate, and four nitrogenous bases (adenine, guanine, cytosine, and thymine). The base and sugar collectively form nucleoside, while base, sugar, and phosphate form nucleotide (Fig. 1.2 ). These are arranged in particular orientation on DNA called order or sequence and contain information to express them in the form of protein. DNA has double helical structure, with two strands being complimentary and antiparallel to each other, in which A on one strand base pairs with T and G base pairs with C with two and three bonds, respectively. DNA is the long but compact molecule which is nicely packaged in our nucleus. The DNA is capable of making more copies like itself with the information present in it, as order or sequence of bases. This is called DNA replication. When the cell divides into two, the DNA also replicates and divides equally into two. The process of DNA replication is shown in Fig. 1.3 , highlighting important steps.

The double helical structure of DNA where both strands are running in opposite direction. Elongation of the chain occurs due to formation of phosphodiester bond between phosphate at 5′ and hydroxyl group of sugar at 3′ of the adjacent sugar of the nucleotide in 5–3′ direction. The sugar is attached to the base. Bases are of four kinds: adenine (A), guanine (G) (purines), thymine (T), and cytosine (C) (pyrimidines). Adenine base pairs with two hydrogen bonds with thymine on the opposite antiparallel strand and guanine base pairs with three hydrogen bonds with cytosine present on the opposite antiparallel strand

The process of DNA replication. The DNA is densely packed and packaged in the chromosomes. The process requires the action of several factors and enzymes. DNA helicase unwinds the double helix. Topoisomerase relaxes DNA from its super coiled nature. Single-strand binding proteins bind to single-stranded open DNA and prevent its reannealing and maintains strand separation. DNA polymerase is an enzyme which builds a new complimentary DNA strand and has proofreading activity. DNA clamp is a protein which prevents dissociation of DNA polymerase. Primase provides a short RNA sequence for DNA polymerase to begin synthesis. DNA ligase reanneals and joins the Okazaki fragments of the lagging strand. DNA duplication follows semiconservative replication, where each strand serves as template which leads to the production of two complimentary strands. In the newly formed DNA, one strand is old and the other one is new (semiconservative replication). DNA polymerase can extend existing short DNA or RNA strand which is paired to template strand and is called primer. Primer is required as DNA polymerase cannot start the synthesis directly. DNA polymerase is capable of proofreading, that is, correction of wrongly incorporated nucleotide. One strand is replicated continuously with single primer, and it is called as leading strand. Other strand is discontinuous and requires the addition of several primers. The extension is done in the form of short fragments called as Okazaki fragments. The gaps are sealed by DNA ligase. Replication always occurs in 5′–3′ direction

DNA contains whole information for the working of the cell. The part of the DNA which has information to dictate the biosynthesis of a polypeptide is called a “gene.” The arrangement or order of nucleotides determines the kind of proteins which we produce. Each gene is responsible for coding a functional polypeptide. The genes have the information to make a complimentary copy of mRNA. The information of DNA which makes RNA in turn helps cells to incorporate amino acids according to arrangement of letters for making many kinds of proteins. These letters are transcribed into mRNA in the form of triplet codon, where each codon specifies one particular amino acid. The polypeptide is thus made by adding respective amino acids according to the instructions present on RNA. Therefore, the arrangement of four bases (adenine, guanine, cytosine, and thymine) dictates the information to add any of the 20 amino acids to make all the proteins in all the living organisms. Few genes need to be expressed continuously, as their products are required by the cell, and these are known as “constitutive genes.” They are responsible for basic housekeeping functions of the cells. However, depending upon the physiological demand and cell’s requirement at a particular time, some genes are active and some are inactive, that is, they do not code for any protein. The information contained in the DNA is used to make mRNA in the process of “ transcription” (factors shown in Table 1.1 ). The information of mRNA is used in the process of “ translation” for production of protein. Transcription occurs in the nucleus and translation in the cytoplasm of the cell. In translation several initiation factors help in the assembly of mRNA with 40S ribosome and prevent binding of both ribosomal subunits; they also associate with cap and poly(A) tail. Several elongation factors play an important role in chain elongation. Though each cell of the body has the same genetic makeup, but each is specialized to perform unique functions, the activation and expression of genes is different in each cell. Thus, one type of cells can express some of its genes at one time and may not express the same genes some other time. This is called “temporal regulation” of the gene. In the body different cells express different genes and thus different proteins. For example, liver cell and lymphocyte, would express different genes. This is known as spatial regulation of the gene. Therefore, in the cells of the body, the activation of genes is under spatial regulation (cells present at different locations and different organs produce different proteins) and temporal regulation (same cells produce different proteins at different times). The proteins are formed by the information contained in the DNA and perform a variety of cellular functions. The proteins may be structural (responsible for cell shape and size), or they may be functional like enzymes, signaling intermediates, regulatory proteins, and defense system proteins. However, any kind of genetic defect results in defective protein or alters protein folding which can compromise the functioning of the body and is responsible for the diseases. Figure 1.4 shows the outline of the process of transcription and translation with important steps.

Table 1.1

Factors involved in transcription process

It shows the process of transcription and translation. Transcription occurs in the nucleus and requires the usage of three polymerase enzymes. RNApol I for rRNA, pol II for mRNA, and pol III for both rRNA and tRNA. RNApol II initiates the process by associating itself with seven transcription factors, TFIIA, TFIIB, TFIID, TFIIE, TFIIH, and TFIIJ. After the synthesis, preRNA transcript undergoes processing to form mRNA by removal of introns by splicing and polyadenylation and capping. Protein synthesis is initiated by formation of ribosome and initiator tRNA complex to initiation codon (AUG) of mRNA and involves 11 factors. Chain elongation occurs after sequential addition of amino acids by formation of peptide bonds. Then polypeptide can fold or conjugate itself to other biomolecules and may undergo posttranslational modifications as glycosylation or phosphorylation to perform its biological functions

The biotechnological tools are employed toward modification of the gene for gain of function or loss of function of the protein. The technique of removing, adding, or modifying genes in the genome or chromosomes of an organism to bring about the changes in the protein information is called genetic engineering or recombinant DNA technology (Fig. 1.5 ). DNA recombination made possible the sequencing of the human genome and laid the foundation for the nascent fields of bioinformatics, nanomedicine, and individualized therapy. Multicellular organisms like cows, goats, sheep, rats, corn, potato, and tobacco plants have been genetically engineered to produce substances medically useful to humans. Genetic engineering has revolutionized medicine, enabling mass production of safe, pure, more effective versions of biochemicals that the human body produces naturally [20–22].

The process of recombinant DNA technology. The gene of interest from human nucleus is isolated and cloned in a plasmid vector. The gene is ligated with the help of DNA ligase. The vector is transformed into a bacterial host. After appropriate selections, the gene is amplified when bacteria multiply or the gene can be sequenced or the gene can be expressed to produce protein

The technological advancements have resulted in (1) many biopharmaceuticals and vaccines, (2) new and specific ways to diagnose, (3) increasing the productivity and introduction of quality traits in agricultural crops, (4) the ways to tackle the pollutants efficiently for sustainable environmental practices, (5) helped the forensic experts by DNA fingerprinting and profiling, (6) fermentation technology for production of industrially important products. The list is very long with tremendous advancements and products which have boosted the economy of biotechnology sector worldwide [16]. The biotechnology industry and the products are regulated by various government organizations such as the US Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and the US Department of Agriculture (USDA).

Medical Biotechnology

This fieldof biotechnology has many applications and is involved in production of recombinant pharmaceuticals, tissue engineering products, regenerative medicines such as stem cell and gene therapy, and many more biotechnology products for better human life (Fig. 1.6 ). Biotechnological tools produce purified bio-therapeutic agents on industrial scales. These include both novel agents and agents formerly available only in small quantities. Crude vaccines were used in antiquity in China, India, and Persia. For example, vaccination with scabs that contained the smallpox virus was a practice in the East for centuries. In 1798 English country doctor Edward Jenner demonstrated that inoculation with pus from sores due to infection by a related cowpox virus could prevent smallpox far less dangerously. It marked the beginning of vaccination. Humans have been benefited incalculably from the implementation of vaccination programs.

Various applications of medical biotechnology

Tremendous progress has been made since the early recombinant DNA technology (RDT) experiments from which the lively—and highly profitable—biotechnology industry emerged. RDT has fomented multiple revolutions in medicine. Safe and improved drugs, accelerated drug discovery, better diagnostic and quick methods for detecting an infection either active or latent, development of new and safe vaccines, and completely novel classes of therapeutics and other medical applications are added feathers in its cap. The technology has revolutionized understanding of diseases as diverse as cystic fibrosis and cancer. Pharmaceutical biotechnology being one of the important sectors involves using animals or hybrids of tumor cells or leukocytes or cells ( prokaryotic, mammalian) to produce safer, more efficacious, and cost-effective versions of conventionally produced biopharmaceuticals. The launch of the new biopharmaceutical or drug requires screening and development. Mice were widely used as research animals for screening. However, in the wake of animal protection, animal cell culture offers accurate and inexpensive source of cells for drug screening and efficacy testing. Pharmaceutical biotechnology’s greatest potential lies in gene therapy and stem cell-based therapy. The underlying cause of defect of many inherited diseases is now located and characterized. Gene therapy is the insertion of the functional gene in place of defective gene into cells to prevent, control, or cure disease. It also involves addition of genes for pro-drug or cytokines to eliminate or suppress the growth of the tumors in cancer treatment.

But the progress so far is viewed by many scientists as only a beginning. They believe that, in the not-so-distant future, the refinement of “targeted therapies” should dramatically improve drug safety and efficacy. The development of predictive technologies may lead to a new era in disease prevention, particularly in some of the world’s rapidly developing economies. Yet the risks cannot be ignored as new developments and discoveries pose new questions, particularly in areas as gene therapy, the ethics of stem cell research, and the misuse of genomic information.

Many bio-therapeutic agents in clinical use are biotech pharmaceuticals. Insulin was among the earliest recombinant drugs. Canadian physiologists Frederick Banting and Charles Best discovered and isolated insulin in 1921. In that time many patients diagnosed with diabetes died within a few years. In the mid-1960s, several groups reported synthesizing the hormone.

The first “bioengineered” drug, a recombinant form of human insulin, was approved by the US Food and Drug Administration (FDA) in 1982. Until then, insulin was obtained from a limited supply of beef or pork pancreas tissue. By inserting the human gene for insulininto bacteria, scientists were able to achieve lifesaving insulinproduction in large quantities. In the near future, patients with diabetes may be able to inhale insulin, eliminating the need for injections. Inhaled insulinproducts like Exubera® were approved by the USFDA; however, it was pulled out and other products like Technosphere® insulin (Afrezza®) are under investigation. They may provide relief from prandial insulin. Afrezza consists of a pre-meal insulinpowder loaded into a cartridge for oral inhalation.

Technosphere technology: The technology allows administration of therapeutics through pulmonary route which otherwise were required to be given as injections. These formulations have broad spectrum of physicochemical characteristics and are prepared with a diverse assortment of drugs with protein or small molecule which may be hydrobhobic or hydrophilic or anionic or cationic in nature. The technology can have its applicability not only through pulmonary route but also for other routes of administration including local lung delivery.

The first recombinant vaccine, approved in 1986, was produced by cloning a gene fragment from the hepatitis B virus into yeast (Merck’s Recombivax HB). The fragment was translated by the yeast’s genetic machinery into an antigenic protein. This was present on the surface of the virus that stimulates the immune response. This avoided the need to extract the antigen from the serum of people infected with hepatitis B.

The Food and Drug administration (FDA) approved more biotech drugs in 1997 than in the previous several years combined. The FDA has approved many recombinant drugs for human health conditions. These include AIDS, anemia, cancers (Kaposi’s sarcoma, leukemia, and colorectal, kidney, and ovarian cancers), certain circulatory problems, certain hereditary disorders (cystic fibrosis, familial hypercholesterolemia, Gaucher’s disease, hemophilia A, severe combined immunodeficiency disease, and Turner’s syndrome), diabetic foot ulcers, diphtheria, genital warts, hepatitis B, hepatitis C, human growth hormone deficiency, and multiple sclerosis. Today there are more than 100 recombinant drugs and vaccines. Because of their efficiency, safety, and relatively low cost, molecular diagnostic tests and recombinant vaccines may have particular relevance for combating long-standing diseases of developing countries, including leishmaniasis (a tropical infection causing fever and lesions) and malaria.

Stem cell research is very promising and holds tremendous potential to treat neurodegenerative disorders, spinal cord injuries, and other conditions related to organ or tissue loss.

DNA analysis is another powerful technique which compares DNA pattern [14] after performing RFLP and probing it by minisatellite repeat sequence between two or more individuals. Its modification, DNA profiling (process of matching the DNA profiles for STS markers in two or more individuals; see chapter 18), which utilizes multilocus PCR analysis of DNA of suspect and victims, is very powerful and is useful in criminal investigation, paternity disputes, and so many other legal issues. The analysis is very useful in criminal investigations and involves evaluation of DNA from samples of the hair, body fluids, or skin at a crime scene and comparison of these with those obtained from the suspects.

Improved Diagnostic and Therapeutic Capabilities

The sequencing of the human genome in 2003, has given scientists an incredibly rich “parts list” with which to better understand why and how disease happens. It has given added power to gene expression profiling, a method of monitoring expression of thousands of genes simultaneously on a glass slide called a microarray. This technique can predict the aggressiveness of cancer.

The development of monoclonal antibodies in 1975 led to a medical revolution. The body normally produces a wide range of antibodies—the immune system proteins—that defend our body and eliminate microorganisms and other foreign invaders. By fusing antibody-producing cells with myeloma cells, scientists were able to generate antibodies that would, like “magic bullets,” bind with specific targets including unique markers, called antigenic determinants ( epitopes), on the surfaces of inflammatory cells. When tagged with radioisotopes or other contrast agents, monoclonal antibodies can help in detecting the location of cancer cells, thereby improving the precision of surgery and radiation therapy and showing—within 48 h—whether a tumor is responding to chemotherapy.

The polymerase chain reaction, a method for amplifying tiny bits of DNA first described in the mid-1980s, has been crucial to the development of blood tests that can quickly determine exposure to the human immunodeficiency virus (HIV). Genetic testing currently is available for many rare monogenic disorders, such as hemophilia, Duchenne muscular dystrophy, sickle cell anemia, thalassemia, etc.

Another rapidly developing field is proteomics, which deals with analysis and identification of proteins. The analysis is done by two-dimensional gel electrophoresis of the sample and then performing mass spectrometric analysis for each individual protein. The technique may be helpful in detecting the disease-associated protein in the biological sample. They may indicate early signs of disease, even before symptoms appear. One such marker is C-reactive protein, an indicator of inflammatory changes in blood vessel walls that presage atherosclerosis.

Nanomedicine is a rapidly moving field. Scientists are developing a wide variety of nanoparticles and nanodevices, scarcely a millionth of an inch in diameter, to improve detection of cancer, boost immune responses, repair damaged tissue, and thwart atherosclerosis. The FDA has approved a paclitaxel albumin-stabilized nanoparticle formulation (Abraxane® for injectable suspension, made by Abraxis BioScience) for the treatment of metastatic adenocarcinoma of the pancreas. Nanoparticles are being explored in heart patients in the USA as a way to keep their heart arteries open following angioplasty.

Therapeutic proteins are those, which can replace the patients naturally occurring proteins, when levels of the natural proteins are low or absent due to the disease. High-throughput screening, conducted with sophisticated robotic and computer technologies, enables scientists to test tens of thousands of small molecules in a single day for their ability to bind to or modulate the activity of a “target,” such as a receptor for a neurotransmitter in the brain. The goal is to improve the speed and accuracy of therapeutic protein or potential drug discovery while lowering the cost and improving the safety of pharmaceuticals that make it to market.

Many of the molecules utilized for detection also have therapeutic potential too, for example, monoclonal antibodies. The monoclonal antibodies are approved for the treatment of many diseases as cancer, multiple sclerosis, and rheumatoid arthritis. They are currently being tested in patients as potential treatments for asthma, Crohn’s disease, and muscular dystrophy. As the antibodies may be efficiently targeted against a particular cell surface marker, thus they are used to deliver a lethal dose of toxic drug to cancer cells, avoiding collateral damage to nearby normal tissues.

Agricultural Biotechnology

The manhas made tremendous progress in crop improvement in terms of yield; still the ultimate production of crop is less than their full genetic potential. There are many reasons like environmental stresses (weather condition as rain, cold, frost), diseases, pests, and many other factors which reduce the ultimate desired yield affecting crop productivity. The efforts are going on to design crops which may be grown irrespective of their season or can be grown in frost or drought conditions for maximum utilization of land, which would ultimately affect crop productivity [24]. Agricultural biotechnology aims to introduce sustainable agriculturalpractices with best yield potential and minimal adverse effects on environment (Fig. 1.7 ). For example, combating pests was a major challenge. Thus, the gene from bacterium , the Bt gene, that functions as insect-resistant gene when inserted into crop plants like cotton, corn, and soybean helps prevent the invasion of pathogen, and the tool is called . This management is helpful in reducing usage of potentially dangerous pesticides on the crop. Not only the minimal or low usage of pesticides is beneficial for the crop but also the load of the polluting pesticides on environment is greatly reduced [24].

Various applications of agricultural biotechnology