Chapter 4 addresses the last of the overarching trends considered by the committee: the involvement of a variety of scientific and technical disciplines beyond biology in life sciences research. After a brief introduction to the diversity of fields now involved in the life sciences, the chapter focuses on the intersection of biology and chemistry, which may be particularly relevant for both the Biological Weapons Convention (BWC) and the Chemical Weapons Convention (CWC).
Life sciences research draws on the expertise not only of biologists but increasingly also on scientists from engineering, mathematics, computer science, chemistry, materials science, and many other disciplines. The importance of integrating contributions drawn from these multiple disciplines and applying them to life sciences challenges has been recognized in a variety of recent reports and articles (NRC, 2009b, 2010a, 2011c; Sharp et al., 2011), and was illustrated by many of the presentations during the Beijing workshop.
This integration of biology with other disciplines is an essential component of a vision of the life sciences articulated in the 2009 NRC report, A New Biology for the 21st Century.
Biology is at a point of inflection. Years of research have generated detailed information about the components of the complex systems that characterize life—genes, cells, organisms, ecosystems––and this knowledge has begun to fuse into greater understanding of how all those components work together as systems. Powerful tools are allowing biologists to probe complex systems in ever-greater detail, from molecular events in individual cells to global biogeochemical cycles. Integration within biology and increasingly fruitful collaboration with physical, earth, and computational scientists, mathematicians, and engineers are making it possible to predict and control the activities of biological systems in ever greater detail. . . . [T]he life sciences have reached a point where a new level of inquiry is possible, a level that builds on the strengths of the traditional research establishment but provides a framework to draw on those strengths and focus them on large questions whose answers would provide many practical benefits. (NRC, 2009b:12-13)
The value of integration across disciplines to addressing challenges in biomedicine was also highlighted by President Obama in remarks to the 2009 Annual Meeting of the National Academy of Sciences.
Because of recent progress–-not just in biology, genetics and medicine, but also in physics, chemistry, computer science, and engineering—we have the potential to make enormous progress against diseases in the coming decades…. [w]e can harness the historic convergence between life sciences and physical sciences that’s underway today; undertaking public projects–-in the spirit of the Human Genome Project—to create data and capabilities that fuel discoveries in tens of thousands of laboratories; and identifying and overcoming scientific and bureaucratic barriers to rapidly translating scientific breakthroughs into diagnostics and therapeutics that serve patients. (White House, 2009b)
Although the concept of converging or integrating biology with other disciplines is not new and reflects approaches that many individual scientists are already taking, it remains challenging to clearly define. One definition was presented in a white paper on the topic issued by the Massachusetts Institute of Technology (MIT) in 2011 (Sharp et al., 2011). The authors state that convergence is not only the small area of intersection between fields, but also a new research model that represents “the merging of distinct technologies, processing disciplines, or devices into a unified whole that creates a host of new pathways and opportunities. It involves the coming together of different fields of study—particularly engineering, physical sciences, and life sciences—through collaboration among research groups and integration of approaches that were originally viewed as distinct and potentially contradictory” (Sharp et al., 2011:4) (see Figure 4.1).
Although the language used in describing this model varies somewhat from author to author, integration or convergence entails adapting
FIGURE 4.1 A diagram of the conceptual difference between intersection and convergence of biology, chemistry, and engineering.
SOURCE: Yamamoto (2011), reprinted and adapted with permission.
and applying the tools and conceptual, analytical, and technical “ways of looking” (NRC, 2010a) used by disciplines in the physical sciences and engineering to challenges in the biological sciences in order to bring new insight to problems. Reciprocally, approaches and understandings derived from the biological sciences are adapted and applied to address physical sciences questions (NRC, 2010a; Sharp et al., 2011). Although many of the existing scientific techniques cited in documents that emphasize the integration and convergence of multiple disciplines in the life sciences are familiar to the research community (e.g., genetic engineering, synthetic biology, etc.), there is a sense that the reduced costs and increasing availability of technology are making them more routine and are accelerating the pace at which research is progressing. As part of this paradigm, many scientists and engineers anticipate the development of new capabilities, techniques, and understandings that are not comfortably housed within conventional disciplines and that represent an expansion into new research areas.
The Beijing workshop clearly reflected the multidisciplinary and integrative nature of modern life sciences research and highlighted the growing diversity of fields relevant to the future of the BWC. Although areas covered during the workshop are discussed in greater detail in Chapters
1. The importance of mathematical modeling to fields as diverse as systems biology and disease surveillance. Quantitative models provide new tools for understanding interactions and relationships among biological entities and for predicting system behavior as the components or conditions are altered. As just one example, the E-cell project was launched in 1996 to create a virtual model of a minimal cell based on Mycoplasma genitalium (Tomita et al., 1999). As knowledge in fields like omics and systems biology has continued to advance, more complex cells and cellular pathways have been explored and modeled (http://www.e-cell.org). Modeling is also used to study and predict patterns of emerging infectious disease in populations (Lin, 2010). As described in Chapter 2, the range of complexity and variability in biological systems renders it challenging to reduce them to networks of mathematical equations and computer code. Even if such models are not yet capable of fully capturing or predicting all aspects of a particular system, however, the application of modeling tools derived from mathematical and computational sciences is helping to advance numerous life sciences research agendas.
2. The integration of chemistry, materials science, and biology in order to design new biomaterials for use in targeted drug and gene delivery and in tissue engineering. A wide range of active research is ongoing in this area, including the chemical design of materials that respond to physical changes like temperature or pH, conjugation of ligands onto new drug or gene carriers that interact with biological receptors to improve targeted uptake of nanoparticles into cells, and the design of polymer scaffolds that support the proliferation and development of cells for use in tissue regeneration (Ying, 2010). Many biological molecules of interest, from bioactive proteins and peptides to synthetic drugs to nucleic acids, have reduced environmental and physiological half-lives without protection provided by encapsulation, or have undesired side effects if administered non-selectively. As a result, the integration of multiple disciplines to create novel delivery systems and biomaterials is likely to continue as a significant area of interest in the life sciences.
3. The field of synthetic biology, which seeks to combine perspectives from engineering and computer science with genetics and molecular biology in order to design new, purposely constructed biological components and systems. Modular components composed of molecules such as
proteins are combined into devices that perform specific functions (for example, particular biological pathways), and these devices are in turn combined into larger systems. In this fashion, synthetic biologists seek to apply principles of engineering design drawn from areas such as electronic circuit construction to living systems. Although many challenges remain, the field integrates physical sciences and engineering approaches with those in the life sciences with the goal of ultimately creating novel biological applications.
These areas highlight just a few of the ways that knowledge from diverse fields such as mathematics, computational science, materials science, chemistry, and engineering are combined with advances in cellular and molecular biology to make important contributions across the life sciences.
Attention has increasingly been paid to the ways that chemistry and biology are converging and to the implications this convergence might have for the nonproliferation obligations for States Parties of the BWC and CWC. From their inception, the BWC and CWC have overlapped in their coverage of molecules that have biological effects. The text of the BWC and subsequent understandings established at five-year review conferences make clear that the treaty covers biological agents and toxins, whether natural or synthetic, whatever their origin or method of production, along with their components (United Nations, 2007, 2011). The CWC, meanwhile, covers “any chemical which through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals…regardless of their origin or of their method of production” (OPCW, 2005). All biological molecules are fundamentally also chemicals, and studies of the action of chemicals that act on life processes to cause harm and the development of countermeasures against them draw on both the biological and chemical sciences.
The convergence between chemistry and biology and potential areas of overlap between the BWC and CWC include certain categories of molecules—such as biological toxins and biological regulators (bioregulators)—and developments that affect the mechanisms of production of chemical and biological substances. These themes are introduced briefly below, followed by a discussion of some of their potential implications.
4.3.1 Biological Toxins
A toxin is a poisonous substance produced by a biological organism and is generally a small molecule or a peptide or protein that causes harmful effects when it interacts with specific components of a living
system. Different toxins exhibit various mechanisms of action, and their severity and lethality also vary significantly. For example, several species of gastrointestinal bacteria produce and secrete enterotoxins, which generally act by altering ion permeability across the membranes of cells in the intestine and cause vomiting and diarrhea. Botulinum toxin produced by the bacterium Clostridium botulinum, on the other hand, interferes with release of the signaling molecule acetylcholine at junctions between nerve and muscle cells and causes paralysis. Toxins whose effects are particularly severe are generally highly regulated. Both saxitoxin, produced by certain types of marine plankton and bacteria and a cause of shellfish poisoning, and ricin, produced by the castor oil plant, are included on Schedule 1 of toxic chemicals under the CWC and thus are subject to declaration and verification protocols (OPCW, 2011a). Various toxins are also subject to national regulations such as those that apply in the United States under Department of Health and Human Services and Department of Agriculture select agent regulations.1
Many toxins are produced by microorganisms. The wealth of microbial diversity is still being explored, and techniques that allow the genomes of multiple microbial species to be sequenced without needing to individually isolate and culture each one are expected to continue rapidly expanding our knowledge of microbial systems. As new microbial species are identified and studied, it seems likely that new biological toxins also will be discovered. Although toxins are defined as substances having a harmful effect, it is important to note that they also play significant roles in basic and applied biological research for beneficial purposes. For example, studies using botulinum toxin have advanced basic science understanding of the process of neurotransmitter release, and the toxin has also been studied and employed extensively as a clinical treatment for diseases involving muscle spasms (Lim and Seet, 2010; Truong et al., 2009) and for esthetic purposes. Toxins or modified versions of toxins have also been tested as components of therapeutic agents directed against cancer or for improved tumor imaging (Engedal et al., 2011).
It should be noted that toxins are defined by their means of production or effect. There is no way to define them chemically—as discussed above,
1 Select agents are defined by U.S. government regulations (Title 42, Code of Federal Regulations (CFR) Part 73 and 9 CFR 121), and laboratories working with materials on the list are subject to additional forms of registration, oversight, and other restrictions. The Select Agents and Toxins List currently includes botulinum toxin, ricin, saxitoxin, and several others (see http://www.selectagents.gov/select%20agents%20and%20toxins%20list.html). Other countries also have national policies that govern the safe handling, research, and transfer of pathogens and toxins, and these are supplemented by a number of regional and international efforts; a brief review may be found in Responsible Research with Biological Select Agents and Toxins (NRC, 2009c:64-67).
they range from small molecules to proteins. This is challenging from the perspectives of both definitions as well as detection methodologies.
4.4.2 Biological Regulators
Bioregulators are small molecules that modulate physiological function, for example by activating or inhibiting enzymes, binding to cellular receptors and activating signaling pathways, and influencing DNA regulation. These substances act as neurotransmitters and hormones and are frequently based on or derived from individual amino acids and small peptides. There are a large number of bioregulators, including, for example, the neurotransmitters gamma-aminobutyric acid (GABA) and glutamate, biologically active peptides such as oxytocin, enkephalin, vasopressin, neuropeptide Y, and substance P, lipid-soluble steroid hormones such as cortisol, and protein hormones such as insulin.
Bioregulators affect multiple aspects of physiological systems in a variety of different ways—influencing metabolism and blood pressure, the immune and nervous systems, pain sensing, and many other processes. Some of the effects of oxytocin, for example, are discussed in Section 2.1.4. As a result of their wide-ranging effects, the low doses at which they act, their potentially rapid onset of action, and the fact that as normal components of physiological regulatory systems they would be less likely to trigger immune responses, bioregulators are potentially attractive targets to exploit. Discussions of the potential military, terrorist, or law enforcement uses of molecules such as biological regulators and their dual use implications have been recognized widely for a number of years (Bokan et al., 2002; Dando, 2002; Davison and Lewer, 2004; Kagan, 2006; Kelle et al., 2008; Nixdorff, 2010; NRC, 2005). However, their practical use may be limited by factors such as the need to better understand their effects, the need to encapsulate or otherwise render them suitable for aerosol delivery, and their short biological half-lives. As scientific knowledge advances on several of the fronts discussed in Chapter 2, however, these molecules may become more relevant. The ever-increasing understanding of biological systems may yield new knowledge of how bioregulators function and how they might be used to modulate system properties to desired ends. Advances in methods for producing or synthesizing peptides and proteins and for effectively delivering them (protecting them from degradation and assuring that they reach targeted cells or tissues) may also ultimately make these types of molecules easier to employ.
Advances in the understanding of bioregulators are not confined to humans and animals. Some of the most exciting advances in plant biology are in plant defense against insect pests and pathogens, such as the discovery of systemin, an 18-amino acid peptide in tomato and potato
(and probably in many other plant species), the first peptide hormone known in plants (Bergey et al., 1996; Pearce et al. 1991, 2001). Of further interest, this signaling pathway is analogous to the inflammatory response in animals to pathogens, whereby a polypeptide activates release of arachidonic acid, which leads to synthesis of prostaglandin.2
4.3.3 Advances in Techniques for Production:
Chemical Synthesis of Biological Molecules
and Biological Synthesis of Chemicals
Other authors have explored the increasing convergence between chemistry and biology with a focus on how S&T advances alter possible methods of production for molecules like toxins, regulators, and drugs. In particular, developments in S&T enable both chemical synthesis of biological molecules and biological synthesis of chemicals (Tucker, 2010, 2011b).
Although substances such as toxins and regulators are naturally produced by living organisms, advances in synthetic methods increasingly allow them to be made by chemical means. The genomes of viruses and small bacteria also have been synthetically created (Gibson et al., 2010; Wimmer et al., 2009). Both chemical synthesis using nucleotide building blocks (to assemble nucleic acids such as DNA and create synthetic genetic material) and chemical synthesis using amino acids (to assemble peptides and proteins) are becoming faster and easier, while the costs associated with the processes are decreasing (see Sections 2.1 and 2.2 for further discussion).
It is also feasible to use biological molecules and biological systems in the production of chemicals such as drugs. The use of molecular biology, genetics, and cell culture techniques to create recombinant bacteria and transgenic organisms capable of producing specific proteins and peptides is well known and has been exploited by the pharmaceutical industry
2 When a Colorado potato beetle takes a bite from a leaf of potato or tomato, it induces a wound response that includes release of one or more protease inhibitors inimical to the digestion by the insect. Systemin is the protease-inhibitor-inducing factor, released from prosystemin upon wounding. Systemin then moves in nanomolar amounts to neighboring cells where it binds to a transmembrane receptor and leads to production of jasmonic acid (JA). JA, in turn, mediates long-distance signaling expressed as systemic production of the protease inhibitors and hence starvation of the leaf-chewing insects by inhibition of their digestive enzymes. Formation of more prosystemin is also induced by JA, thereby providing an amplification loop for the systemic defense response.
for many years in the production of “biologics.”3 As discussed in Section 2.1.5, advances in protein production in transgenic systems, including plants (sometimes referred to as “pharming”), continue to improve such efforts. As science advances, it is also increasingly possible to design metabolic pathways in biological systems that can produce additional types of chemical drugs. Research exploring terpenoid biosynthetic pathways, for example, enabled the metabolic engineering of yeast to produce the anti-malarial drug precursor artemisinic acid (Ro et al., 2006), and research on the synthesis of alkaloid molecules is also being conducted (http://keaslinglab.lbl.gov).4 Other groups are working to design bacteria capable of converting fatty acid molecules into hydrocarbons to develop biologically derived fuels (Schirmer et al., 2010; Service, 2008). Biological enzymes can also be used as components in organic chemistry syntheses to catalyze reactions (referred to as biocatalysis). The use of enzymes in such reactions is attractive because the specificity of enzymes improves the ability to conduct difficult syntheses that distinguish between closely similar chemicals, resulting in a better yield of the desired product and reduced need to separate out mixed impurities. Enzymes function in aqueous solutions and at physiological temperatures, allowing reactions to proceed at lower temperatures than might otherwise be required, although enzyme stability may be a concern for certain industrial applications. Enzymes are also degradable and are thus less environmentally toxic than some other chemicals for use in green chemical synthesis.
4.3.4 Discussion and Implications of
the Convergence of Biology and Chemistry
Bioactive molecules such as bioregulators and biotoxins fall into a middle spectrum of agents ranging from classical chemical weapons (such as nerve gases) on one end to classical biological weapons (such as viruses and bacteria) on the other, and bioregulators in particular have been described as “prototypic nontraditional threat agents” (Kagan, 2006). As the life and chemical sciences continue to advance rapidly, this potential
3 Biologics are medical products of biological origin and “can be composed of sugars, proteins, or nucleic acids or complex combinations of these substances, or may be living entities such as cells and tissues. Biologics are isolated from a variety of natural sources—human, animal, or microorganism—and may be produced by biotechnology methods and other cutting-edge technologies…. In contrast to most drugs that are chemically synthesized and their structure is known, most biologics are complex mixtures that are not easily identified or characterized. Biological products, including those manufactured by biotechnology, tend to be heat sensitive and susceptible to microbial contamination” (http://www.fda.gov/AboutFDA/CentersOffices/CBER/ucm133077.htm).
4 Alkaloids are a large class of molecules generally synthesized in plants that includes drugs such as morphine.
mid-spectrum area of overlap between the BWC and CWC may continue to expand in several ways:
• Advancing knowledge will result in more molecules that fall within areas of overlap (such as toxins and regulators) being discovered and characterized;
• Ongoing research to understand the mechanisms of action of relevant biological molecules, their roles in physiological systems, and their regulation will generate improved understanding of how such molecules could be used;
• Advances will continue to be made in biological and chemical production technology, for example that make it easier to produce proteins, peptides, and drugs in transgenic animal and plant systems, in small-scale, cell culture bioreactors, and by chemical synthesis;
• Advances in delivery technology will continue to address limitations such as rapid degradation and need for targeted delivery to cells and tissues (including to the central nervous system), thus potentially rendering it more feasible to deliver agents such as bioregulators; and
• New research fields that exemplify scientific convergence, such as synthetic biology, will continue to develop.
The report of an advisory panel convened in 2011 by the Director General of the Organisation for the Prohibition of Chemical Weapons (OPCW) on future priorities for the CWC notes:
This convergence calls for a closer interaction in the implementation of the [CWC] Convention, and the Biological Weapons Convention. Convergence in the sciences does not in itself lead to convergence of the regimes, but exchanges of experience and joint technical reviews could be helpful to understand how it affects the implementation of both treaties at the interface between chemistry and biology. That is particularly pertinent as there is an overlap between the two treaties with regard to the prohibition of toxin weapons. (OPCW, 2011b:20)
The convergence of scientific disciplines, including chemistry and biology, was highlighted at the international scientific workshop convened in 2006 prior to the Sixth BWC Review Conference (Royal Society, 2006b) and at the 2007 international scientific workshop convened by the International Union of Pure and Applied Chemistry (IUPAC) prior to the Second CWC Review Conference (Balali-Mood et al., 2008). This report draws attention to it again because it remains a significant feature of current research in the life sciences and chemistry. In April 2011 the Scientific Advisory Board of the OPCW recommended the establishment of a Tem-
porary Working Group to consider the implications of chemical-biological convergence for the CWC (OPCW, 2011c). Convergence is also expected to be a topic at a workshop to be convened by IUPAC in early 2012 to examine trends in S&T prior to the Third CWC Review Conference.
For many years, discussions of relevant S&T areas for the BWC have involved more than the traditional microbial threat agents that were the focus of national offensive biological weapons programs prior to the treaty’s entry into force in 1975. The increasing integration of the physical, engineering, and mathematical sciences with the biological sciences continues to expand the scope of these discussions. This continuing expansion of relevant areas of S&T may pose several challenges for the BWC and for the scientific community. As research in the life sciences draws increasingly on knowledge and techniques from other disciplines, the range of expertise necessary to track the state of scientific developments and to assess their potential implications also expands. The BWC has been making efforts to engage members of the life sciences community through its intersessional meetings and through presentations at scientific conferences.5 These efforts are continuing to foster awareness of the BWC and of the norms and requirements it contains. Given the diversity of potentially relevant fields that are coming together to address challenges in the life sciences, expanding outreach to new scientific stakeholders who have not traditionally been part of the “life sciences” community may need to be considered.
Previous reports have noted the institutional, financial, and educational challenges associated with convergence between the life and physical sciences, including the structures of traditional academic departments, systems of incentives and promotion that may not sufficiently credit multi-author and collaborative projects, and the need for enhanced cross-disciplinary education as part of core training requirements (NRC, 2010a; Sharp et al., 2011). An additional challenge is the creation of ethical frameworks for responsible science that bridge communities that may be
5 Intersessional topics including “improving national capabilities for disease surveillance, detection and diagnosis and public health systems” (2010), “enhancing international cooperation, assistance and exchange in biological sciences and technology for peaceful purposes” (2009), and “laboratory safety and security of pathogens and toxins” (2008) related directly to science. In addition to making presentations at meetings focused on biosafety, bioethics, and biosecurity, the BWC Implementation Support Unit has also participated in recent scientific community gatherings such as the 2010 International Genetically Engineered Machine Competition (iGEM) and the 2009 meeting of the International Association for Synthetic Biology (http://www.unog.ch/bwc/isu).
accustomed to discussing similar ethical themes in different ways, and have dif6 For example, in the case of synthetic biology, many practicing cell biologists and microbiologists focus on the end product (“it looks like what we already do”) and not the engineers’ emphasis on the fact that the process to get there was different. Similarly, a bioengineer may publish a paper on developing a reproducible scalable process to promote cell-based production of a compound. In contrast, traditional biology is usually focused on understanding “how it works,” not “how do I use it to accomplish X?” Thus, even though responsible conduct across fields such as engineering and biology is likely to address common topics such as integrity, conflicts of interest, protection of propriety information, and decision-making consistent with public safety and welfare, the examples used to illustrate these concepts may differ.
Finally, the convergence of disciplines may pose challenges to the operation of regimes like the BWC and the CWC. New scientific developments might alter or expand the types of agents that could be of concern as biological or chemical weapons and/or might alter or expand the definitions of which molecules fall under the purview of both treaties. One possible role for the scientific community may be exploring and clarifying the technical issues surrounding these advances in chemistry and biology, to inform efforts to better define the nature and scope of the challenges they present. Ongoing scientific dialogue as well as the types of policy dialogues suggested by the OPCW advisory panel (OPCW, 2011b) might contribute to the consideration of the future challenges to both treaties posed by advances in S&T, including future threat agents and their methods of production.
Despite these potential challenges, the integration of diverse perspectives and the convergence of multiple disciplines in the life sciences remains an exciting trend. The model of convergence in the life sciences is one that may provide many creative new opportunities to address challenges across areas like health, energy, agriculture, and the environment.
6 Information from a workshop organized by the U.S. National Academy of Engineering and the Woodrow Wilson Center on whether and how engineering ethics might inform the development of synthetic biology, for example, may be found at http://www.onlineethics.org/Topics/EmergingTech/TechEdu/SynBioWorkshop.aspx.