Microbial resources have always been in demand either for their most valued secondary metabolites or the bioremediatory processes which they mediate. Amongst all physiological groups of bacteria extremophiles especially those from the poles are mostly sought after. Extremophiles are interesting to both basic and applied biologists. These organisms hold many exciting biological potential, such as the biochemical extremes to macromolecular stability and the genetic basis for constructing macromolecules stable at different extreme conditions. The microorganisms have yielded an amazing array of enzymes capable of catalysing specific biochemical reactions under extreme conditions. Such enzymes are in high demand in biotech industry for diverse applications, for example laundry detergent additives as proteases and lipases or in the genetic identification in forensic science (Taq DNA polymerase and its use in the polymerase chain reaction, PCR).
Another important realisation that has emerged from the study of extremophiles is that some of these organisms form the origin of life itself. Many extremophiles, in particular the hyperthermophiles, lie close to the ‘universal ancestor’ of all extant life on Earth. Thus, an understanding of the basic biology of these organisms is an opportunity for biologists to ‘look backward in time’ at a period of early life on Earth. This fascinating realisation has fuelled much research on these organisms in order to understand the nature of primitive life forms, how the first cells ‘made a living’ in Earth’s early days, and how early organisms set the stage for the evolution of modern life forms. The Polar systems, especially in the Antarctic, harbours microbes with some properties that link the extant to the extinct. Most importantly they have withstood the test of time and therefore have high application potential.
Extreme conditions at the poles
The Polar systems are known for the extremities in environmental conditions. The temperature could fluctuate from -14 to -89oC and so can salinity and light from below detection limits up to 1700 micro moles m2 s-1 PAR at 60oN. Paradoxically certain regions could be extremely arid without any liquid water. However, the toughest of extremities could be due to hypersaline conditions as this evokes the expression of the highest number of genes as compared to other extreme conditions (Thomas et al. 2010). A combination of all these environmental forcings can be encountered in polynyas.
Polynya is a large body of open water or an area covered by very thin ice that persists in the middle of winter sea ice in the polar regions. The area of open water is surrounded by sea ice therefore it could be viewed as unfrozen sea within the ice pack. Generally, many polynyas recur in the same region every year due to physical processes responsible for their formation. Deep water polynyas form beyond the shelf break. Coastal polynyas are important areas of sea ice formation during the winter. They occur adjacent to a coastal promontory. Antarctic coastal polynyas are biologically very productive, and offer ideal conditions for seasonally early and intense phytoplankton blooms. Due in part to the lack of a thick ice cover, polynyas form ‘windows’ through which the ocean can receive relatively high levels of sunlight from early spring onwards. The open waters then retain more heat that continues to thin the ice cover. These areas within polynyas are important for marine mammals such as killer whales to surface and breathe and also for sea birds, especially during winter.
However, in such ecosystems the microbes face the challenge of encountering extreme variability in environmental parameters especially salinity. Examining some adaptations in these microbes could help appreciate their linkages with the environment. It is important to understand the range of tolerance and inhibition and optimal levels of activity in these systems under natural conditions in order to be able to harness the processes they mediate or the products they form under simulated conditions.
An interesting feature of hypersaline environments is the formation of gradients in concentration with respect to time. As small bodies of hypersaline waters evaporate, the salinity gradually increases. With evaporation it could increase five times the initial value of 1M causing natural fluctuations in the halophilic species that inhabit that particular body of water. When water has around 1M to 3M NaCl, the environment could be dominated by algae, protists, and yeasts. At 5M, some of these organisms could get eliminated due to intolerance to such high salinity. Organisms that can survive at these higher salt concentrations, such as red-orange halobacteria, drastically increase in numbers until the water body is completely dried up or diluted back to a lower salinity. The increases in red-orange halobacteria populations could be dramatic, colouring the whole water body red with cells reaching a density of 108 cells per ml. Nevertheless, the toughest halophile also needs to maintain internal and external balance in solutes and osmotic pressure. Since these organisms are in hypertonic solution, water diffuses out of the cells and into the surrounding environment. This even would cause non-halophilic organisms to plasmolyze or, if the organism does not have a cell wall, the organism would shrivel. Both these reactions would be lethal to the organism (Campell et al., 2002). Usually, the organism would take up sodium ions to create equilibrium between the interior and the exterior cellular environments. However, since sodium ions at such high concentrations would be potentially lethal within a cell, most halophiles accumulate potassium ions while actively expelling sodium ions to create osmotic equilibrium (Garabed, 2001). Besides, potassium ions, halophiles also accumulate other non-disruptive solutes to maintain equilibrium. These can include amino acids, glycine, betaine, ecotine, and sucrose (Das Sharma et al., 1991).
Other adaptations include those at protein and membrane level. Microbes of polynya function under conditions that can lead to denaturation of proteins. Halophiles can compete for water and overcome the denaturing eﬀects of salt. Their proteins are capable of competing effectively with salt for hydration. This property confers the ability to resist other low water activity environments as in the presence of organic solvents. In order to combat denaturation, aggregation, and precipitation of proteins at high salt concentrations, proteins of halophiles often contain a high ratio of acidic to basic amino acids. This adaptation would make the surface of the proteins negatively charged thus allowing it to get solvated in a high salt environment. Besides, membranes of halophiles are unique in their composition. Their protein bacteriorhodopsin and retinal that is found in their membranes are in lattice shaped areas. Consequently, >50 per cent of the entire membrane surface is purple coloured.
The sensory rhodopsins help mediate the phototactic response and purple membrane allows phototrophic growth. The protein functions as a light dependant proton pump. Fall in levels of oxygen or high light intensity in this protein is induced to support phototropic growth.
Bacteriorhodopsins have interesting applications as in biocomputing, (optical computing, optical memories, holography) or even in spatial light modulators. Halophiles also have novel gas vesicles which help flotation of the organisms in liquid or change depths to find oxygen and salt concentrations to match their requirements (Das Sarma et al., 1999). Their gas vesicles have been models for bioengineering floating particles and their pigments could be used as additives for safer food colourants. Yet, the compatible solutes could act as stabilisers, salt antagonists or stress protectors. Thus halophiles are evolutionary relics. The archeae have been here for 3.5 bya. They are the terrestrial analogues for extra-terrestrial life and give us insight into fundamental constraints on the range of hospitable environments.
The polar region is also subject to a combination of other extreme conditions like very low temperatures and high amounts of ultra-violet radiation—making it a near perfect, natural laboratory for exploring the result of natural selection under extreme conditions. Perhaps the most surprising, was the discovery of a previously unidentified species of Deinococcus bacteria living 15 m below the permafrost. These bacteria are very robust and can withstand exposure to radiation—specifically, gamma radiation—many thousands of times more than any other known organism. Intriguingly, this intensity could never have been encountered on planet Earth. Hence one is tempted to speculate that this adaptation could have only resulted if the progenitor bacterial species could have evolved from somewhere outside the Earth, that is, having an extraterrestrial origin. (Planetsave, http://s.tt/12vf0)
Therefore, it is important that one understands the environment in which organisms flourish and evolve before it could be harnessed for either the processes they mediate or the secondary metabolites they produce. Microorganisms continuously interact with their environment and adapt themselves and this interaction confers certain properties on them. It is common knowledge that microbes owe all their extra-ordinary properties to the environment from which they originate. For example microbes endowed with the property of tolerating ambient heavy metal concentration would in due course of time lose this property if they are maintained in an environment that is more benign without high metal concentrations. Plasmids or extrachromosomal DNA is readily taken from the environment when required and the baggage got rid of when not required. Chromosomally mediated properties may however last for a longer time but not for too long. Besides the environmental modulation at a given time, there is also the temporal dictates like seasonal, annual, decadal rhythm that all of the organisms including microbes follow. It is of utmost importance that these aspects are adequately addressed when exploring and harnessing fauna and flora for their bioactive potential. With the growing realisation that consistency in the process or products may not always be the norm, importance is now being given to understand microbe-environment interaction before effectively using them for biotechnological applications. Besides, this also helps watch the conservation aspects of the environment in question.
Consequently, it is not surprising that there are a number of biotechnological companies interested in the bioresources of the polar regions. About 43 companies are involved in research on or the actual harnessing of biotechnology and there are well over 31 patents or patent applications based on Arctic genetic resources, such as anti-freeze proteins, bioremediation, pharmaceuticals, nutraceuticals and dietary supplements, cosmetics and other health care. It is however known that commercial interest in the Arctic genetic resources may however be much larger than what patent analysis suggests. Such commercial activities in the Arctic and Antarctic present challenges for the sustainable management of these ecosystems and resources. The problem is more aggravated by climatic changes due to which many of the species of the frozen environments of the polar regions, including the microorganisms of the sea ice of interest for biotechnology, appear threatened (Loka Bharathi, 2011). The (Figure 1) gives an idea of the different aspects for which the bioresources are harnessed.
Linkages and contextual parameters
There is growing scientific and commercial interests in the Polar microbes-products and processes, consequently impacting the environment by repeated assaults. This not only calls for timely regulations but also suitable and powerful environmental diplomacy and governance with stress on the importance of ecological aspects. We have to evolve from snapshot analyses where the emphasis is more on components to temporal observations laying importance to linkages more than components with due emphasis on emergent properties of interactions. We may need to accelerate our pace of getting to improve our basic understanding of systems in tune with imminent climatic changes. Giving importance to environmental linkages would then become less random and more directed, sustained and more efficient. A particular combination of environmental factors would lead to particular traits in products as it is the environment that nurtures these properties. It was rightly articulated by Baas Becking as early as in 1934 that “Everything is everywhere but the environment selects!”(Baas Becking, 1934). By increasing our ability to monitor, model and predict we would be able to harness resources in a more consistent and sustainable manner. We would be able to capture a major combination of environmental drivers before the imminent climatic changes bring in major changes. More importantly we could become more sensitive and responsive. The time-tested microbes could be harvested responsibly along with thoroughly documented combination of factors and understanding of their interaction that elicit certain responses that are biotechnologically useful. With this type of knowledge and collective wisdom we could evolve guidelines for equitable sharing of future commons needs to be formulated. Our efforts could be geared towards well thought sampling strategies along with inclination for sample sharing and effective storage and retrieval. Meticulous implementations would help realise that the arduous task was more worthwhile in the long run as it is known that “Life did not take over the globe by combat but by networking” (Margulis and Dorion Sagan, 2001).
Commercial pursuits in the Arctic and Antarctic are a cause for concern and pose a challenge for the sustainable management of the resources that these ecosystems harbour. The problem could get serious with climatic changes which could cause many of the species of the frozen environments of the polar regions, including the microorganisms to become vulnerable. There are many differences between the climate and environment of the Arctic and Antarctic which in turn are reflected in significant differences in Antarctic and Arctic ecosystems and biodiversity. The relative ease of access to Arctic biodiversity for research purposes should be contrasted with the logistical difficulties of access to Antarctic. The status of the genetic resources of marine areas beyond national jurisdiction is emerging as a significant issue to be discussed and resolved.
The status of genetic resources of marine areas both within and beyond national jurisdiction has been the focus of diplomatic discussions in many forums (UN-DAOL, 2005). These include meetings associated with the 1992 Convention on Biological Diversity, the International Seabed Authority, the United Nations Informal Consultative Process on the Law of the Sea, the annual debates of the United Nations General Assembly on Oceans and the Law of the Sea, and more recently, the deliberations of Ad Hoc Open-ended Informal Working Group to study issues relating to the conservation and sustainable use of marine biological diversity beyond areas of national jurisdiction. The distinction between marine scientific research and bioprospecting apparently requires to be more explicit to help formulating policies and a formal system of regulation for sharing of future commons.
Accordingly, there is also a growing need for sound scientific advice to support policy development and delivery. This calls for attempts to improve the channels of communication between scientists and policy makers. This could be achieved by interfacing effectively between knowledge producers and people who use it. One realises that both speak different languages and therefore there has to be a common understanding with positive communication in both directions with policy makers being vocal about the direction they wish to go, what evidence may be needed and which areas require greater explanation. With world-class excellence in terms of knowledge that has been generated over the last decade, there has been much more excitement and engagement of scientists, engineers and technologists to publicise their research findings. Public funding, whether national or international could prove eventually useful when ideas get converted into innovative practices, devices, treatments, and technologies (Smith 2012).
In the Rio de Janeiro summit of 1992, the dominant topics were green economy and natural capital accounting. Green economy aims not to commoditise natural resources like ecosystems. Bottom-up approach to development was another buzz word which indicated that participation of local (read Arctic) inhabitants could be imperative. This is to avoid green accounting from becoming too protectionist which otherwise could intrude into development space and thus impact human rights. Different perspectives could converge to evolve a prioritisation of rights for developing countries. Instead of creating blanket solutions the strategy would be to pay attention to local requirements and conditions.
To this end, there continues to be new challenges for both environmental diplomacy and governance. Faunal and microbial interaction with the environment and the emergent properties of interactions and the products thereof would give a new perspective to bioprospecting microbes from extreme environment like the Arctic or the Antarctic. Microorganisms are known to be pivotal to various useful processes and the services they have been rendering. With insights into their lifestyle and fitness, we could augment and refine our ability to monitor, model and predict future changes. Such understanding of ecosystems in both spatial and temporal dynamics would help harness resources in a more consistent and sustainable manner. The need of the hour is on concerted effort in this direction before the imminent climatic changes cascade into major shifts in the prevailing ecosystems. International dialogue on collaborative projects could include ‘Information Flow and Intellectual Property Rights’ as one of the important themes.
- Antranikian, G., 2001, ‘Extremophiles’, Nature Encyclopedia of Life Sciences, January, Nature Publishing Group: London.
- Baas Becking, LGM. (1934), ‘Geobiologie of inleiding tot de milieukunde’, Diligentia Wetensch, Series 18/19, W.P. Van Stockum & Zoon N.V, The Hague: Netherlands, 249-254.
- Campbell, N.A., Reece, J.B. (2002), ‘Biology’, 6th edition, Benjamin Cummings, San Francisco.
- DasSarma, S., Arora, P. (1999), ‘Halophiles’, Nature Encyclopedia of Life Sciences, July, Nature Publishing Group: London.
- LokaBharathi, P.A. (2011), ‘Changing climate and microbial resources in Polar realms’, National Conference on Science and Geopolitics of Arctic and Antarctic: SaGAA 2011, New Delhi, 14-15 January 2011, (New Delhi: Learning in Geography, Humanities, Technology and Science, LIGHTS): 48-50.
- _____ (2005), ‘UN -DOAL (Division of Ocean Affairs and the Law of the Sea) August, 2005’. One of the contributors to Environment and Biodiversity beyond National Jurisdiction including information on technologies used for their study and use any relevant environmental concerns.
- Margulis, L., Sagan, D. (2001), ‘Marvellous microbes’, Resurgence, 206: 10-12.
- Planetsave (http://s.tt/12vf0)
- Smith, L. (2012), ‘Science and policy: An interview with Professor Anne Glover’, Science.
- Thomas, T.R.A., Kavlekar, D.P., LokaBharathi, P.A. (2010), ‘Marine drugs from sponge-microbe association’: A review, Marine Drugs, 8:4: 1417-1468.
- UNU-IAS Report. (2008), ‘Bioprospecting in the Arctic’