The number of taxonomically defined animal species is around 1.5 million. These are classified into 32 phyla according to their distinct features. One of these is the phylum of Tardigrada.

These cute, tiny water creatures were discovered in 1773 by Johann August Ephraim Goeze. Despite being aquatic, these animals were called “water bears” because of their legs; and because of their resemblance to pandas, they were named “Tardigrada,” meaning “slow stepper,” by the Italian biologist Lazzaro Spallanzani. Tardigrades also look like dwarf rhinos and armadillos. There are about 1,000 different species in the Tardigrade phylum.

Tardigrades live in habitats with variable amounts of humidity, from high mountains to deep oceans, and from polar regions to the equator. They are especially found in lakes, freshwater springs, or on stone walls, mosses, lichens, leaves, and litter.

As cute, charismatic, miniature animals, tardigrades can be seen under a microscope. The length of adults can reach 1.5 mm, while the smallest ones are under 0.1 mm; their larval length is only around 0.05 milimeters. Their body is covered with a strong but elastic material.

Animals grow in two ways: via an increase of cell numbers or the enlargement of a single cell. In Tardigrades, generally the latter is observed. These animals possess a hard external skeleton, like insects, and this structure changes as they grow.

Their bodies are composed of five sections: a distinct head in addition to four body parts, each equipped with claws. They walk using the short, blunt feet under their bodies. Their clawed legs help them cling to sand particles or plant surfaces. Their hind legs are used for snatching and slow acrobatic movements. They have a sharp mouth, called a “stylet,” which enables them to consume plant cells, algae, small invertebrates, and even their own kind.

They are provided with anatomical and physiological features similar to larger animals, including a digestive track and system: a mouth, esophagus, stomach, small intestine, anus, well developed muscles, a pair of abdominal nervous systems, and a brain. The body lumen of Tardigrades are filled with a fluid that is in contact with every cell and this provides them with their necessary nutrition and gas exchanges without the need for a circulatory or respiratory system. Their respiration occurs throughout their body surfaces. Because of their physiology and ability to quickly reproduce, Tardigrades can be used as a model organism for education and research. The cell count of certain species of Tardigrades at birth never changes during their lives. While some species contain around 40,000 cells, some have fewer. Their reproduction can be sexual, but it also can occur via parthenogenesis (offspring development without the fertilization of the egg).

Tardigrades: Organisms of extreme conditions

Tardigrades are created with a resistance to a wide range of temperatures, pressures, and radiation. Therefore, they can live in environments where many living things die. They can survive a temperature of 150 C for minutes, and can also live at minus 200 C without suffering any damage for days; they can even stay alive at temperatures near absolute zero (−273 C).

Some Tardigrades can live at extreme low pressures, including situations approaching a vacuum, or at extreme high pressures, such as 600 times the normal atmospheric pressure. This pressure is six times the pressure present at the depths of the Mariana trench, the deepest part of the Earth’s oceans (roughly 11,000 meters). This was discovered when Tardigrades were taken to space and exposed to different pressures. When brought back to Earth, they were still alive.

They can also survive in environments with no humidity for 10 years, and they can stay alive in places where radiation is 1,000 times more (5000 Gy to 6200 Gy) than many organisms can endure (10 Gy is fatal for humans).

Hibernation – a dead phase

How does a Tardigrade stay alive in detrimental conditions?

When they are exposed to conditions unsuitable for life, they enter a semi-dead phase called Cryptobiosis. One of the most distinct changes during this state is that their metabolic speed slows down to near zero, and they experience programmed dehydration. In very low temperatures, Tardigrades’ water ratios drop from 85% to 3%. This way, damages that can occur by freezing are prevented. As is well-known, the main hazard during freezing is the cell membrane damage caused by the crystallization of cellular water.

During the dehydration stage, trehalose sugars are synthesized (this also happens when Tardigrades are faced with low temperatures). This sugar prevents possible damages to the cell membranes during freezing and water loss. This sugar is very intriguing for the pharmaceutical industry because of its potential use in the prevention of freezing-related damages in organ transplants.

Another benefit of dehydration is resistance to radiation. This is because reactive molecules generated in the cell by the effects of radiation cannot cause a reaction in a dehydrated medium; due to the low water concentration, the possibility of harmful reactions drops.

Cryptobiosis does not only take place during dehydration. It also happens during periods of low temperature (cryobiosis), high salinity (osmobiosis), and low oxygen. By being able to hibernate, Tardigrades are important for space research. Maybe during interplanetary trips, passengers could be hibernated by freezing.

Tardigrades could have other uses for medical purposes. Certain disease-causing microorganisms could be dehydrated without killing them via Cryptobiosis. This way, “weakened organisms” contained in vaccines get to be stored in a dry fashion, eliminating the need for freezers, making them easier to store and distribute. Similar technologies could also be employed for the conservation of seeds, sperms, blood, and various nutrients.

Brittlestars form a large group of sea animals that are similar to starfish. There are more than 2,000 species of brittlestars. However, this article will focus on two of them, Ophiocoma pumila (Figure 1a) and Ophiocoma wendtii (Figure 1b). In spite of their similar appearance, these two kinds of brittlestars have one main difference. While O. pumila is insensitive to light, O. wendtii is highly light sensitive. For example, the latter has different colors at day and night, as shown in Figure 1b, left and right respectively. More interestingly, O. wendtii can sense shadows of predators and quickly move into dark areas such as a cave or underneath a rock.

To understand the mechanisms behind the difference in light sensitivities of these two species, Joanna Aizenberg and her colleagues investigated1 the microstructure of both brittlestars’ outer skeletons with an electron microscope and came up with a striking result: The top surface of O. wendtii’s skeleton has very well ordered lens-like hemi spherical elements (Figure 1f). The cross section image of one of those hemispheres actually looks like a compound lens made up from two hemispheres with different diameters (Figure 1g). On the other hand, O. pumila’s skeleton had a typical stereom (sponge-like calcite) structure (Figure 1e). These images strongly suggest that the lenses in O. wendtii’s skeleton are responsible for the relatively high light sensitivity. However, understanding how that really happens require further investigation.

It is well-known that spherical lenses suffer from a problem called “spherical aberration,” which means that the light rays that are closer to the optical axis are focused at a different point than the ones that are away from the axis. A quick solution to this problem is to use two lenses, whose diameters have a certain ratio, back to back; this helps to correct the aberration originating from the first one with the second one. Interestingly, when Aizenberg et. al. calculated1 the optimum compound lens configuration for O. wendtii’s skeleton, which has the minimum aberration, their result matched the original lens structure perfectly (the orange outline in Figure 1e). They were also able to locate the focal point of these lenses (d = 4-7 um* below the lens) with the same method. Their further electron microscopy studies showed optically sensitive nerve bundles exactly at that location. All these results clearly show that O. wendtii’s skeleton has the perfect geometry to collect and focus light to improve its light sensitivity. However, there is one big question about these lenses: their material.

Calcite, a kind of calcium carbonate (CaCO3), is a common ingredient of the shell or the skeleton of marine organisms. Interestingly, the birefringence property of calcite makes it very unfavorable as a lens material. In a birefringent material the speed of the light depends on the direction it travels with respect to the crystallographic axes of the material. As a result, if one looks through it, they will observe a doubly refracted image (Figure 2). Being the most famous example of birefringent crystals, calcite’s refractive index is 1.64 parallel to one crystallographic axis and 1.49 in the perpendicular direction. Therefore a regular calcite lens cannot focus light on a single spot, unless it is oriented along a special crystallographic axis (c-axis to be specific), which would be along the diagonal of the prism in Figure 2.

At this point we are not surprised to learn that the optical axis of the O. wendtii’s lenses, and the c-axis of the calcite crystal that they are made of, indeed overlap. We are not surprised because we already had a strong feeling that these lenses should work. However, it is quite surprising that these little creatures can grow single crystals of calcite with a specific crystallographic orientation. As Kenneth Towe states in the context of a similar study, “This precise orientation of crystals is the big mystery of biomineralization. Organisms know how to do it; we do not yet know how they know.”3

Biomineralization, the controlled deposit of inorganic minerals by living organisms, is a very active research field attracting many scientists from various disciplines, including biology, physics, chemistry, and material science. In general, controlling crystal structures at small length scales is a very challenging task. Scientists spend millions of dollars to build state-of-the-art facilities for single crystal materials synthesis. They work in clean rooms, under an ultra high vacuum and at extremely high temperatures. On the other hand, from brittlestars to large whales, almost all living creatures have biominerals, such as bones and shells, manufactured in chemically dirty environments and at decent temperatures. Organisms are apparently equipped more efficiently than our laboratories are.

A. Ali Eren has a Ph.D. in Physics and lives in the USA. He studies physical chemistry of biological processes.

References

*1 um (micron) is one thousandth of a millimeter. Human hair is approximately 100 micron thick.

1. Aizenberg, Joanna, et al. “Calcitic microlenses as part of the photoreceptor system in brittlestars.” Nature 412.6849 (2001): 819-822.
2. ttp://jademellor.com/blog/2013/6/21/rainbow-rhombus, accessed 4/20/2014
3. Towe, Kenneth M. “Sea urchins as crystallographers.” Science 311.5767 (2006): 1554-1555.

Organic substances in the soil go through oxidative decomposition depending on factors such as temperature, air, humidity, and pH balance. This is a slow burning (oxidation) event of organic substances. However, oxidative decay is hindered if one of the aforementioned factors is lacking. Then, a slow decay of organic materials in soil called humification takes place.

Humification occurs in an open system in contact with air. For example, early chemical processes start with leaves changing color in autumn. The break down and partial ingestion of leaves by soil organisms follows. During this time, water soluble carbohydrates and proteins leave the leaf tissue. What remains behind are plant structures like cellulose and lignin, which are not broken down yet. Since leaf shapes are not completely deformed, species identification can still be possible at this stage. In the decay step, however, the cellulose and lignin are decomposed by various fungi species and converted to humus.

Humic substances and their properties

Humic substances are intermediate products that occur as the result of organic materials going through a series of chemical reactions. These intermediate products are humic acid, fulvic acid, and humate. Their molecular weights are around 1.000-10.000 gr/mol, 10.000-100.000 gr/mol, and 100.000-10.000.000 gr/mol, respectively. Humic acids contain weak aliphatic (carbon chains) and aromatic (carbon rings) organic acids that are soluble in water when it has a base medium but insoluble under acidic conditions.

Fulvic acids with smaller size molecular structures can reach plant roots, branches, and leaves easily because they are soluble in water under all pH conditions (acidic, neutral, and basic). Thus, trace elements such as iron, zinc, copper, manganese, and boron can be easily transported to plant tissues via fulvic acid.

Humates, however, are insoluble in water. Only the portion of a humate called ulmic acid can dissolve in alcohol.

Major functions have been assigned to humic matter in the nutrient and carbon cycle, as they are inseparable members of the ecosystem. Plants capture significantly more nutrients from humic matter than from clay minerals. Even though they can be depleted from soil by certain agricultural practices in less than 50 years, they can still remain in natural soils, outside human activity, for hundreds or even thousands of years without being degraded. This very long presence in soil enables them to continue their functions longer. According to radiocarbon dating, humates can last approximately 1140 years; and humic acid and fulvic acid last for 1235 and 870 years, respectively, in natural soils.

Positively charged nutritious elements (cations) remain in the soil by binding to negatively charged (anions) in humic matter. Because this bond is weak, useful elements for the plant can easily be exchanged with another cation, becoming free and getting absorbed by the plant. On the other side, cations such as iron, copper, zinc, magnesium, manganese, and calcium, which are hazardous to plants when taken excessively, are held in the soil, bound to humic matter and thus not causing toxicity.

Another significant feature of humic and fulvic acid is their ability to form water bridges. Water bridges facilitate the movement of nutrient ions towards roots via soil solutions.

Aside from agriculture, humic matter, with its aforementioned properties, serve humankind in the industrial, environmental, and biomedical fields.

Industrial and environmental applications

Humic matter is utilized in the staining of leather works, as wood lining paint (natural blue color), as well as water based stripping material for furniture stains. Humic matter is also used in the production of durable, resistant papers in the paper industry, to provide mechanical strength to processed ceramics, and as an additive. It is also applied as a coloring, hardening, and plasticizing agent in plastic fabrication.

Humic and fulvic acids gain significance regarding their ability to form water soluble substances with many metal compounds containing radioactive elements in their structure.

In environmental chemistry, the main role of the humic matter is to remove toxic substances, human sourced organic chemical matter, and other pollutants from water. Calcium humate, obtained from humic matter, can bind and remove nickel, iron, cadmium, and copper in addition to radioactive elements produced at nuclear power plants from water.

Humus based filters are designed to treat sewage water and mud waste. Oils, stains, poisonous phenolic substances, and pesticides are removed from sewage via these materials. In poultry, humic substances are employed to absorb and eliminate the odor of waste gases.

Biomedical applications

Drugs for the treatment of human and animal diseases are developed from humic matter. These can be used for the treatment of viral and bacterial illnesses, in the prevention of blood clots, to cure infections, and to remedy estrogen deficiencies. Clinical studies have shown that common viral diseases of children’s respiratory tracks can be treated with fulvic acid supplements. A lot of medical research has shown that humic matter, especially fulvic acids, have the ability to provide protection against cancer causing viruses. In a study, laboratory mice were given ethanol to trigger gastritis and it was determined that humic acids supplied to mice led to a significant reduction in the harm gastritis caused. The fact that humic acids can form compounds with heavy metals, such as cadmium, enables the excretion of heavy metals from organisms.

In our universe there is no place for waste. Once every particle completes its task, it is returned in a different fashion to be assigned another job. Humification is a good example to this reassignment as a complex recycling event in the soil. It is amazing to observe everything being generated from one thing and everything converted into one thing so easily and in such a crafty, balanced, and organized fashion. In fact, the power and wisdom behind the conversion of the remains of millions of different organisms into a few similar substances to be employed in different tasks are no less amazing.

Some insight for leaves

Leaves are in charge of respiration in plants. They consist of the main mechanism producing food for plants, using sunlight via photosynthesis through which food for many more organisms, animals, and humans are provided. Having been assigned to convert solar energy to food, which they’ve been doing for millions, perhaps billions, of years, plants have been a significant instrument for sustaining life on or planet. It is as if plants turn their leaves upward in prayer to ask for food on behalf of all living things.

Morphology of a leaf

Leaves are composed of three sections: the base, blade, and petiole. The blade is the most important part of the leaf; it is wide and flat. The exact shape of leaves vary according to climate, geographical conditions, life span and risk of consumption by other organisms. In tropical climates, the blade is often very wide. In drier climates, it is usually smaller, in order to reduce water loss.

Leaves of some plants undergo a transformation called “metamorphosis” to fulfill different tasks. For example, some leaves have a thorny shape and protect the plant form herbivorous animals. Some leaves are designed to store water, and some are converted into a trap in order to capture insects to nourish the plant.

On the cross section of a leaf, one can observe that four layers constitute the inner part. The first one is the epidermis, which covers the leaf from top to bottom. This layer protects the leaf against external elements and is lined with a waterproof, waxy substance.

The palisade parenchyma is located on the upper side of the inner tissue and it houses chloroplast rich cells, which are lined up densely and carry out photosynthesis. The spongy layer under the palisade tissue forms the intercellular air spaces and this layer is responsible for the respiration of the plant.

For photosynthesis to occur, the leaf needs to receive the maximum amount of sunlight. The sun must hit the leaf at a perpendicular angle; thus, the leaf must be amply wide and must sit level. Because the sun hits different latitudes at different angles, plants have branches of different lengths facing different directions, and leaves have different curvatures. Furthermore, leaves are also lined up in a way so as not to block the sun’s rays. For this to happen, it is required for the leaf base to be thin and the leaves to be lined up in a spiral fashion that enables both lower and higher ones to harvest sunlight in the most efficient way. This type of arrangement exemplifies the golden ratio, which is observed among many structures in nature.

Each leaf sprouts at an angle of either 222.5 or 137.5, derived from division of 360 degrees, from the previous leaf under. This spiral leaf growth provides them with the most suitable place to harvest sunlight maximally. This way the gaps around branches are minimized and a maximum number of leaves is positioned without reducing the light capture capacity of the plant.

Seasons and leaves

Plants work like factories during spring and summer, producing a great deal of food through photosynthesis. Some of these foods help the plant grow and some are stored as starch for winter. With the onset of autumn, a majority of plants outside tropical zones go through hibernation, like many organisms do, and enter a dormant period. In order for plants, like trees and bushes, to survive the cold, their leaves are shed to minimize their surface area and conserve energy. Perennial green plants lose their aerial parts, too, including stems and leaves, and hibernate underground as roots, bulbs, and tubers. They sprout back from their roots once spring brings warmer weather.

Many leaves begin to fade and fall once autumn arrives. The leaves of some hardy plants – like cypress, pine, and spruce trees – continue to function through winter. In some of these trees, like the bay tree and the Indian sandalwood, there are protective layers covering the leaves against the cold. Other leaves, like pine needles, are created in a spiny shape to resist the cold.

Colors of autumn

Leaves seem green during the spring and summer months because the chlorophyll found in them absorbs all wavelengths other than green. The other major pigments found in leaves are carotene (orange) and xanthophylls (yellow). These two pigments are the most common pigments in nature.

As autumn approaches, and photosynthesis begins to end, chlorophyll starts to degrade and the other pigments begin to show. Thus, leaves turn yellow and bright red.

As the weather gets colder, the chloroplasts that are near the leaf’s bottom are broken apart, and sugar levels begin to elevate. The sugars produced during this season accumulate in the leaves day by day due to lower photosynthetic speed and reduced transportation to other parts of the plant. These sugars are converted into anthocyanins. At first, leaves appear yellow. A couple weeks before they fall, most leaves shift from yellow to red. Under abundant sunlight, due to concentrated anthocyanins, leaves seem brighter and more colorful – and thus red. Once the live tissues die completely, all leaves turn brown. This is due to the high concentration of tannin.

Leaf color varies not only because of plant genetics and external factors, but also because of climate. Temperature, humidity, soil composition, and levels of sun exposure all affect color. There is a higher degree of color change in the leaves of trees that grow in lower temperatures.

The composition of soil plays a major role in the color of leaves. Leaves that turn yellow early indicate a nitrogen shortage; on the other hand, the presence of a strong red color indicates very acidic soil. A high alkaline ratio is present in places where leaves are purple.

Walking among fallen leaves and the colorful scenery in a forest in autumn can trigger unique emotions. Depending on the psychological state of a person, the colors of autumn sometimes remind us about the briefness of this world, but they can also hint at the infinite life to come.

The motifs and patterns of leaves

Receiving sufficient sunlight is a significant matter for leaves. Therefore, they are created differently. No two plant leaves are the same.

Some of the leaves are simple and some are compounds. According to their arrangements, opposite, alternate, whorled, and rowed forms exist. Leaf blades can be ovals, kidneys, triangles, or even hearts. Edges can be smooth, serrated, toothed, or lobed. Leaf veins can also have many different motifs.

Each plant species has its own leaf motif. The alfalfa leaf has a triple pattern of specific angles; walnut leaves have an opposite arrangement of eight to ten. A hand-like motif, like the fingers of a praying hand, formed of seven leaves, can be observed on chestnut trees.

I am sure that there are a lot of people who’ve found themselves in a similar situation to the man above. Unfortunately, most of us are usually not aware of the things happening in this universe. One of the things we tend to overlook is the cleanliness of nature. This is a topic which needs to be considered carefully, but I will just touch on some important aspects of this issue.

First, let’s look at the oceans. The oceans cover three-fourths of the Earth’s surface. There is a bigger world under the ocean than above it. This huge mass hosts jelly fish and tuna, dolphins and octopus, crabs and plankton, sea stars and sea plants. Currently, there are 120,000 species living in the ocean. This is just the number of the species, and doesn’t account for how many variations there are within each species. When we consider the number of living organisms, there are millions of them. Every single day, lots of these organisms die. If there are millions of organisms and thousands of them die each day, then why cannot we see them on the surface of the ocean? Even if these dead organisms are very small, such as plankton, which has a size range from 0.2 m to 20mm, when millions of their dead bodies cluster on the surface, we should be able to see them. The answer lies in a perfect arrangement. For example, the job of cleaning the dead bodies of plankton (also the live bodies!) is performed by fish, sharks, and whales. A large percentage of the daily diet of these animals depends on plankton. Since these animals perform their job well, it is impossible to see any dirt that would have been caused by the dead plankton.

It might seem easy to get rid of the dead bodies of plankton, because they are small organisms. But what about big animals such as whales? What happens to dead whales? Let’s consider the cleaning of dead whales. When a whale dies, its dead body sinks to the bottom of the ocean. This is called a “whale fall” by scientists. There are a lot of species whose diet depends on dead whales. In 1988, a group of researchers at the University of Hawaii found that there are at least 12,490 single organisms which supply their daily diet from a whale fall in the deep North Pacific Ocean. After bigger organisms, such as fish, finish their job, which includes eating the flesh of the dead whale, the other cleaners come to the scene to perform their roles. At this part of the fall, bacteria play a key role in cleaning the bones left from the whale fall. This is not as easy as it might seem. Actually, it takes several years to really clean the dead body from the bottom of the ocean. This is not just a cleaning process at all. While the whale fall is being cleaned from the bottom of the ocean, the ecosystem is supported by the energy from the dead whale.

This cleaning process is not only seen in the oceans, but also on the land. Even though it is more apparent than undersea, we are not totally aware of the cleaning process on land. Decomposition is the chain of events by which a dead organism breaks down to its smaller parts. We must stop here and ask this question: “What would happen if these dead organisms stayed on the land forever?”

So let’s look at what happens to a dead animal on land.

When an organism dies, the process of decomposition starts shortly after its death. There are some stages in the decomposition of an animal. Shortly after the death of the organism, the enzymes in the cytoplasm of the cells start to break down the tissues. This process is called autolysis. It is one of the stages of decomposition in which bacteria plays a role. Bacteria start to break down the tissues. This is called putrefaction. Bacteria are not the only players who have roles in this process. Besides them, some fungi, insects, and even some carnivores are also involved. Live animals, water, air, and temperature (higher temperatures increase the decomposition rate) also help this process. During this time, fungi and bacteria, by using compounds from the dead organisms, convert carbon to carbon dioxide and organic nitrogen to ammonium (NH4+), and so they contribute to both the Carbon and Nitrogen Cycle. After this process is done, many organisms living in the ecosystem have benefitted. At the end of this cycle, soil is enriched with new nutrients which will help the new plants to grow up and the Carbon and Nitrogen cycles are enhanced.

By looking at the processes above, as well as other cycles (e.g. the Carbon cycle), it can be said that the Earth has its own recycling system. While modern societies have only recently understood the importance of recycling, Earth has been using this system thanks to the arrangements given to it.

The things shown here are just some examples of the extraordinary systems existing on the Earth. These systems have always been like this, since the very beginning of the universe. These perfects systems in nature perform their tasks without any human help. The only thing for us to do is to appreciate this harmony, understand its value, and keep it going for the next generations.

Termites are 1-2 cm in size, but they live in mud towers that can grow to five meters tall. The scale, between termite and tower, is comparable to that between a human and a skyscraper. When their life style, which seems chaotic from the outside, is investigated, one finds that termites maintain social lives within perfect urban communities. These wondrous mini cities feature air conditioning and ventilation systems, in addition to a queen chamber, and rooms for incubation and juveniles.

An instinctual sense of solidarity that has been ingrained among living organisms also plays an important role among termites. They display an amazing form of cooperation in matters like foraging and defense. As termites live in colonies, they follow a particular arrangement of duties. The queen is in charge of new generations; workers meet the nest’s needs, and soldiers are responsible for its defense. When necessary, workers also participate in defensive tasks. One of the termite’s defense mechanisms, which amazed scientists, was recently discovered in June 2012.

Jan Sobotnik, with the Academy of Sciences of the Czech Republic, and Thomas Bourguignon, of Université Libre de Bruxelles at French Guiana, discovered an unseen feature of the termite species Neocapritermes taracua. The workers of this species are, in a sense, enlisted to military duty when they “retire” due to old age and an inability to forage due to weakened mouths. They serve the defense of the nest as something of a chemical weapon specialist. When the colony is under attack, these veterans blow up a droplet-size balloon filled with a type of chemical generated in between segments of their neck and dorsal region.

When worker termites get older, blue crystal chambers, which resemble backpacks, grow on their two shoulder blades on their back. These crystals are a kind of protein called hemocyanin that contains copper, and they join together with saliva when under threat. This fusion causes a chemical reaction. The end product is a sticky liquid, like a gel, that is compressed to expand and then burst. This can fatally injure a predator. The poisonous substance that is dispersed causes rotting upon contact. The chemical formula of this blue crystal substance, along with its reactions, are still unknown.

Researchers from Oregon University (USA) reported that the mouth of an ant is worn down by age. When this occurs, these senior individuals, which used to cut leaves, now take on different jobs, like carrying the leaves. Leaf cutter ants, which are also known as the ranchers of the animal kingdom for their ability to cultivate fungi in their nests, can cut and carry leaves whose weight can be up to 50 times their body weight.

The leaves that are transported to the nest comprise the main ingredient required for the growth of fungi in a suitable environment regulated for the right temperature and humidity. This fungi is ultimately used to feed the colony. This is a fine example of senior members of a community staying active in a new role. And this is not just unique to termites: research shows that members of animal societies adapt to changes in their lives, and continue serving their colonies even if they lose some dexterity.

Our universe seems to be set up this way. As mentioned in the above examples, there is a change of occupation instead of just retirement. Just as there is no termite that stops working, there is no bird that says “I do not want to fly anymore because I am old,” or no tree that says, “I will retire and stop giving fruit because of my old age.” Organisms adapt to new conditions and find new ways to provide for our planet.

Our aging planet will continue rotating and the sun will keep smiling on us with its heat and light until the end of such organism’s lifetimes.

When it comes to humans, continuing with occupation and business as much as they can should be the desired effort. Especially for charity work, no one should mention retirement or leave of a duty, and receding to one’s quarters. Let us renew our intentions now, and review our senior living plans.

In recent years scientists have taken huge steps towards the bio-hybrid architecture developed for exploring an alternate approach to the control of autonomous robots (1). The plant-robot interactions through cyborg plants have been investigated in an effort to apply lessons from plants to robots, which provided another role for these organisms other than being a food source or decoration items. There are several joint experimental, numerical and robotic studies conducted in this newly developed area. One of the examples includes a flower robot made by Korean engineers which has the appearance of a common flower with petals, stem and leaves (2). The flower robot has sensing ability, moving mechanism, and home appliance function. It can recognize environmental conditions such as room temperature, pressure, voice and light intensity and can imitate the blooming of a flower, the bending of the stem and the stirring of the leaves in the wind. Other than these, the flower robot functions as a humidifier, a vision/voice recording system and an illumination device. For example, when flower robot receives light, it senses the intensity of the light and blooms. On the contrary, when it is dark, as the flower robot starts fading away and its illumination device turns on to flash the room.

Plantas nomadas, made by Mexican artist Gilberto Espaza, is another example of cyborg plants. It uses dirty water to live. It is a miniature eco-system consisting of plants and micro-organisms within a robotic shell. Each of the components symbiotically relies on the others: the plant provides the perfect environment for the microbe, and the microbe (in a microbial fuel cell) transforms nutrients in dirty water into energy to power the robotic components, and the robotic components provide mobility (3).

A team from Switzerland has been working on a project that endows a robot with the ability to react in response to environmental stress of a plant in order to maintain the state of the plant. The robotic devices monitor the changes in morphology and electrical activity of the avocado plants. According to these parameters, it classifies the drought level and triggers irrigation when necessary (4).

Some of the artists like James Stone, who is a Media Artist specializing in digital technologies and fabrication, are interested in seeing if plants are prone to act in certain ways, show preference and possibly display other traits such as emotion. Artists are specifically curious as to what would happen when a plant is augmented with technology but also given full control over such technology to do with it whatever it chooses (5). To see the results of such systems that provides a means for the plant to interact with people or things will surely be fascinating. A study in this line of research is done by a group of researchers in mobile robotics at ETH Zürich, whose long-term research goal is also to bestow machines with the ability to gain and employ knowledge from the universe to improve their intelligence, by building a prototype called iRobot Create. This cyborg plant consists of a computer running Linux, a normal plant and additional sensors and lives its own life, following its internal needs of water, sunlight and electrical energy (6). The cyborg stays away from obstacles using ultrasonic sensors, finds the best light spot using light sensors and goes to a recharge and to a mock-up water station using iRobot’s infrared sensor. Moreover, its sensors pick up noise caused by people moving around nearby, allowing cyborg plant to react by moving out of the way, to prevent themselves from getting underfoot (7).

It is very important to improve the ability of robots to work successfully in a complex and harsh environment, which would increase their usages. In one of those efforts exploring the use of biological systems to control robots under changing environmental conditions, Dr. David Hu and his group from Georgia Institute of Technology (8) used the Mexican jumping bean, Laspeyresia saltitans, which consists of an empty seed housing a moth larva. Heating by the sun stimulates movements by the larva which rolls, jumps and flips by the bean. They explored this unique means of rolling locomotion and recorded bean trajectories across a series of terrain types, including one-dimensional channels and planar surfaces of varying inclination by Time-lapse videography. They found that the shell encumbers the larva’s locomotion, decreasing its speed on flat surfaces by three-fold. Interestingly, they also showed that the two-dimensional search algorithm of the bean resembles the run-and-tumble search of bacteria. When they tested this search algorithm using both an agent-based simulation and a wheeled Scribbler robot, they demonstrated that the algorithm succeeds in propelling the robot away from regions of high temperature. It is amazing that from a study that involves a plant seed, a moth larva and a robot, scientists may develop applications in biomimetic micro-scale navigation systems.

The hi-tech devices that have been inspired by biological systems are not limited by the ones stimulated with plants. The insect world also represents a huge and original database for future bio-inspired systems, vehicles, and micro-vehicles (9). For example, the process of motion detection system in the fly’s eye is a good example of a neural circuit that was used for robot automatic piloting. Recently, a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats has been presented (10). Other than that, body undulation used by snakes and the physical structure of the body of a snake may offer major advantages over typical legged or wheeled locomotion designs in certain types of scenarios, therefore a large number of research groups have developed snake-inspired robots to make use of these benefits (11). Caenorhabditis elegans, a roundworm which has similar motions with snakes but with a simpler structure, was also selected to develop a small crawling robot with a thermal shape memory alloy, a homogeneous mixture or solid solution of two or more metal, as an actuator (a type of motor for moving or controlling a mechanism or system) due to the similarities of its properties to C. elegans muscles. (12).

Not only multicellular organisms but also unicellular (single-celled) organisms are utilized for generating cyborgs; for example, scientists used circuits prepared from Physarum polycephalum, amoeboid plasmodia of the slime mold, to control an omni-directional hexapod robot. Sensory signals from the macro-physical environment of the robot are transduced to cellular scale and processed using the unique micro-physical characteristics of intracellular information processing and the response from the cellular computation is amplified to yield a macroscopic output action in the environment mediated through the robot’s actuators(1).

In addition, a new biorobotic system using human neuroblastoma cultures was introduced in 2011 by a Spanish engineering group (13). Multielectrode Arrays Setups have been designed for direct culturing neural cells over silicon or glass substrates. The main objective of this work is to run a robot using this biological neuroprocessor and the final system could be used for many things such as testing how chemicals influence the behavior of the robot.

In summary, manipulation of robots that use living organisms as an interface to perceive the environment and transfer their responses into functions seem to have endless applications as well as challenges. Biologically-inspired technologies represent an emerging and promising field of interdisciplinary areas composed of engineering, computer sciences, chemistry, biology, physics and even art. In nature there are so many living and non-living elements designed by God to help us develop and improve robots to make our lives easier, better and more productive. Even a flower can offer us with something more than color and scent, and that is if we start thinking outside the box like so many people mentioned above have done.

Safiye Arslan is a Research fellow in the area of molecular biology in Nevada.

References

1. Tsuda, S., Zauner, K. P., & Gunji, Y. P. (2006). Robot Control: From Silicon Circuitry to Cells, Biologically Inspired Approaches to Advanced Information Technology (pp. 20-32). Osaka, Japan: Springer.

2. H. K. Park, S. H. Park, J. O. Park, (2007) “A study on the Moving Mechanism for Flower Robot,” International Conference on Control, Automation and Systems.

3. http://m.ammoth.us/blog/2010/09/a-cyborg-arboretum/

4. http://www.cyborgplant.com/

5. http://www.manofstone.com/cyborgplants/

6. Stocker, J., Veillat, A., Magnenat, S., Colas, F., Siegwart, R. (2011). Towards Adaptive Robotic Green Plants. TAROS 2011: 422-423

7. http://www.newscientist.com/article/mg21128305.900-robotassisted-plants-find-their-place-in-the-sun.html

8. West, D. M., Lal, I. K., Leamy, M. J., & Hu, D. L. (2012). Locomotion of Mexican jumping beans. Bioinspiration & Biomimetics, 7(3), 036014. doi:10.1088/1748-3182/7/3/036014

9. http://www.ercim.eu/EU-NSF/Bionics.pdf

10. Colorado, J., Barrientos, A., Rossi, C., & Parra, C. (2012). Inertial attitude control of a bat-like morphing-wing air vehicle. Bioinspiration & Biomimetics, 8(1), 016001. doi:10.1088/1748-3182/8/1/016001

11. Hopkins, J. K., Spranklin, B. W., & Gupta, S. K. (2009). A survey of snake-inspired robot designs. Bioinspiration & Biomimetics, 4(2), 021001. doi:10.1088/1748-3182/4/2/021001

12. Yuk, H., Kim, D., Lee, H., Jo, S., & Shin, J. H. (2011). Shape memory alloy-based small crawling robots inspired by C. elegans. Bioinspiration & Biomimetics, 6(4), 046002. doi:10.1088/1748-3182/6/4/046002

13. Ferrández, J. M., Lorente, V., de Santos, D., Cuadra, J. M., de la Paz, F., Alvarez, J. R., & Fernández, E. (2011). Human neuroblastoma cultures for biorobotics. Conference proceedings : … Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, 2011, 6672-5. doi:10.1109/IEMBS.2011.6091645

The first is the preservation of characteristic, long term data imprints that describes the development of an organism in the stable DNA sequences.

Second is the storage of medium term epigenetically featured data that is carried a couple of generations further down the cellular level. Epigenetic information is not stored within nucleotide sequences but in the chemical modifications of these sequences (like the methylation of repeated strings of GC dinucleotide).

Third is the storage of data generated as a result of dynamic interactions between proteins, RNA and DNA in order to adapt to the events and changes during cellular life cycle in the form of nucleoprotein or DNA-protein complexes.

The data generation and storage capacity of DNA in three different hierarchical levels and time periods demonstrates that genome plays a plethora of roles in cellular activities and heredity. Formatting of genome for its generation and storage of data is carried out via DNA sequences of various features. Genomic system is composed of repeating DNA sequences. DNA sequences (satellite) function as a marker as they repeat numerous times in various frequencies. Genome includes genomic folders similar to that of computer systems. These genomic folders, also known as the epigenetic index of genomes, are responsible for the remodeling of chromatin and the coordinated control of genomic functions. Repeating DNA sequences play a critical role in replication of genome (making a copy of DNA), dispersal of copied DNA into daughter cells and construction of support systems that enable organization of chromatins.

It is possible to better understand genomic functions in relation to examples such as memory sticks and hard drives that are used in electronic information systems. The difference between a genome as a basic data-information storage medium from a hard disc is that it can be replicated as required by its nature and these replicas can be transferred to daughter cells. Following examples could be given to illustrate that a genome gains function only when it interacts with various data processing modules in the cell.

1. A copy of genome is produced by cellular DNA replication system
2. Correct localization of each genome copy towards daughter cells is only possible when chromosome segregation system works (the centrosomes and microtubules)
3. The central transcription system is responsible for the copy of data from DNA to RNA. Different gene expression patterns are developed via regulation of transcription time and level with the help of transcription factors and a web of cell signalization.

Very intricately organized genomic system structures are designed through the successive combination of protein encoding sequences, signals distributed in various places and repeating DNA sequences. Formatting of genome resembles formatting of computer programs. Various repeated serial commands of computer software are used to allocate addresses to files independent of the original data contained; different computer systems use different signals and structures to manage programs. In a similar fashion, diverse living species often utilize repeating DNA sequences and chromosomal structures to organize the encoded information and to format their genomes.

Diversity and variation of repeating DNA sequences are building blocks that are constructed into different genomic system structures. Genomes of different organisms bear characteristic system morphology just like computers with various operating systems and hardware. For instance, animal cells are created as a good model to take and incorporate foreign DNA into their genomes. Genetic data transfer among organisms of the same kind is referred to as “vertical gene transfer” whereas transfers between different species, genuses and classes are called “horizontal gene transfer.” Mobile DNA sequences like transposons are very effective horizontal gene transfer agents.

Cellular differentiation and morphogenesis (formation of tissue and organ from cell) is not programmed completely in the primary structure of the DNA sequence. Components of modular programs are encoded in a flexible way and a continuous renewed and recombined arrangement is enabled when needed.

The reason behind creation of different organisms from a single genome is this utilization of such genomic structure. Metamorphosis, that is the development of different organisms like invertebrates such as a caterpillar and a butterfly, is a good example of this feature.

Two organisms from the perspective of the same genomic protein and RNA codes can be considered as two different species. Different genomic structures and repetition of sequences among different organisms are distinctive criteria for the identification of species since these features can lead to mismatch of reproductive cells, different expression patterns of genetic code sequences, and may cause ecological diversity as well. That is why repeated DNA sequences are very important in studying parental relationships. Today, microsatellite DNA as repeated DNA sequences are used to configure biological relations among individuals in forensic sciences. Plant species vary in respect to the repeated sequences in centromeres in their chromosomes; these variations are used for identification of species. Main determinants of genomic system structure are diversity, frequency, and genomic localization of repeated DNA sequences. To explain this with examples, we could say that successively repeated sequences at centromeres, telomere repetitions and transcription, packing of chromatin, repeated sequences that are spread throughout genome in charge of cellular functions like nucleus localization are the main elements of the genome system structure. Genome is a single integrated system that is controlled closely and remotely via communication webs that use repeated sequences.

While explaining the Qur’anic concept of the Manifest Record (36:12) Bediuzzaman Said Nursi, the great renovator of Islamic thought in Turkey in the twentieth century, wrote that the Manifest Record expresses one aspect of Divine knowledge that is related “more to the past and future than to the present. It is a book of Divine Destiny that contains the origins, roots, and seeds of things, rather than their flourishing forms in their visible existence” (30th Word, Second Aim).

Inspired from this view, a seed can be considered as a tiny adorned form of Divinely creative command as programs and indexes and as a determinant for those programs and indexes in the organization of an entire tree. Since the Manifest Record book, as a title of Divine knowledge and command, observes the past and the future rather than the present, the genome of a grain or a seed acts like a library and an archive in which the future and past of an organism is written.

Sequences encoding different information in DNA

Different information types corresponding with various DNA sequences exist in the genome. These DNA sequences that were considered junk for a long time because they were not coding proteins, have in fact been found to be responsible for an amazing array of functions in genomic structure. Some of these sequences include:

1. Group determining sequences that enable coordinated or successive expression of genes,
2. Sequences acting as a marker in charge of initiation and termination during transcription of DNA to RNA ,
3. Signal sequences responsible for conversion of primary immature RNA, sequences into smaller functional RNA molecules,
4. Transcription control sequences that determine the expression frequency of genes,
5. Sequences that identify and mark the initiation regions for intensification and remodeling of chromatins,
6. Sequences that make binding regions which affect the relocation of genome in nucleus or nucleolus,
7. Sequences that target regions where covalent DNA modification (methylation) with functional groups like methyl takes place,
8. Sequences that control and identify the regions responsible for initiation of DNA replication,
9. Sequences that make the structures which enable completion of replication at terminal ends,
10. Sequences at the segregation points that enable equal distribution of copied DNA molecules into daughter cells and centromere sequences,
11. Sequences responsible for guidance during repair of DNA bound errors and damages,
12. Start point sequences used for repackaging of genomes,

Recurring sequences exist in the genomes of many organisms and shows great structural diversity. Recurring elements function as an initiator or terminator for heterochromatin regions. Furthermore they form an important scaffold and binding spots for folding of DNA structure. As if they carry out the job of an architectural mold in specific shaping of genome to be packed into a very limited area. The ratio of repeating sequences in genome (60-90%) is much more than sequences that are encoding proteins and RNA (10-40%). To explain it with an example, chromosomes in human genome are made up of packages of protein-DNA such as heterochromatin and euchromatin. Heterochromatin regions usually make up the regions with no transcription whereas euchromatin regions feature DNA transcription.

The ratio of protein encoding sequences to the entire human DNA is approximately 1.2%. Around 43% of euchromatin regions are composed of recurring and mobile DNA elements. 18% of heterochromatin region is also made of satellite (dense repeating sequences) and mobile DNA elements. Therefore almost 50% of human genomic DNA is composed of these repeating DNA sequences. In bacteria however, these only make up around 5-10% of the genome. These sequences were described as parasitic and junk individual DNA structures up until today and still continues to be described thus by many researchers and scientist. Nevertheless, even today, mobile DNA elements and repeating sequences are accepted as genomic parasites. Recent advances in the last ten years that have demonstrated this is not true, have instead revealed the vital importance of repeating sequences in genomic functions.

Repeating DNA sequences affect chromatin (dense pack of DNA and protein) structure in two ways. Irregular repeating DNA sequence copies contain binding regions for proteins that organize DNA. Heterochromatin (darker since it is densely packed chromatin) inhibits transcription and recombination, delays replication, and generally blocks the reading of information in DNA sequences that contain genetic coding. Heterochromatin regions are distributed throughout the chromosome. Because of this, presence of regions with coupled successive repeated sequences triggers heterochromatin formation.

In fruit flies, placement of protein encoding loci required for eye pigmentation near the heterochromatin blocks in centromeres (phenomenon of position effect) is provided via organization of chromosomes and thus, formation of phenotypic characters are inhibited. The “phenomenon of position effect” is convincing evidence that genome is a major system which is integrated with composition of partially repeating DNA sequences. When heterochromatin amount is increased in XYY male fruit flies, reorganized pigmentation of eye expression decreases. In XO males, when heterochromatin amount decreases, inhibition becomes severe. Changes in levels of protein which binds to special heterochromatin specific DNA regions generate opposite effects. Decrease in these proteins reduces or suppresses “phenomenon of position effect.” Surplus synthesis of these proteins also enriches this effect.

Repeating DNA sequences play an important role in the transfer of genome into daughter cells. For instance, they function in formation of the centromeres as chromosomal binding regions for microtubules, during gamete formation as linear terminals of chromosomes are replicated, and during chromosomal matching. Distribution of repeating sequences plays a major role in configuration of genomic functions. Each genome has genomic system structure that is shaped dependent on the amount of repeating DNA sequences to a major extent.

Going back to Nursi’s explanation of the Manifest Record, we can draw a parallelism between the book of the universe and the book of revelation, the first of which shows us that certain sequences in the genome are repeated for significance and necessity, just as many verses are repeated frequently in the Qur’an with nuances to refer to different meanings, benefits, and purposes, opening a wider space for many interpretations.

A genome is not only a book that contains protein and RNA codes, but also has a complex system structure with many functions for cellular vitality. The most needed sequences are those that are repeated more frequently. They are not pieces of junk DNA as predicted, they are jewels Divinely constructed.

References

• Shapiro J. A. 2001. “Genome Formatting for Computation and Function :Genome Organization and Reorganization in Evolution: Formatting for Computation and Function.” Presented at a symposium on “Contextualizing the Genome,” Ghent University, Belgium, November 25 – 28, 2001 (Ann. N.Y. Acad. Sci., in press)
• Shapiro, J.A. 2005. “A 21st century view of evolution: genome system architecture, repetitive DNA, and natural genetic engineering.” Gene 345, pp: 91–100.
• Shapiro J. A. and Sternberg R. V. 2005. “Why repetitive DNA is essential to genome function.” Biol. Rev., 80, pp. 1–24. Cambridge Philosophical Society.

There are lots of interesting examples of how plants communicate with insects. For instance, in self-defense against insects eating its leaves, a plant emits a volatile chemical that signals other insects, who are predators of those insects eating the plant. A byproduct of such insect communication may allow plants to signal danger to other extremely close, downwind plants. Professor of Entomology, Richard Karban and other researchers from the University of California showed that a cut sagebrush “told” nearby, downwind wild tobacco plants about its injury, and the tobacco plants apparently responded to protect themselves from damage. Over three seasons, researchers clipped leaves of sagebrush plants to mimic insects eating their leaves. The cut sagebrush released volatile chemicals (methyl jasmonate), which the wind carried to nearby downwind plants. The tobacco plants apparently sensed the chemicals-at least the tobacco plants increased production of a defensive agent-that caused their leaves to taste bad to insects. These downwind tobacco plants experienced less than half the leaf damage from grasshoppers and cutworms than control plants (Anon.). In one case study an acacia tree responded to browsing, or being beaten with a stick, by increasing the levels of tannin in its leaves within minutes. Amazingly, the tannin levels then rise in neighboring trees, and, due to its bitter taste, repel the browsers before they can do any further damage (Jacob 2001; Anon.).

What’s more is that plants can also talk to mammals. A study done by Professor Steven Johnson and his research team from the University of KwaZulu-Natal, South Africa, demonstrated how ground-dwelling mammal pollinators are attracted by a rare parasitic plant’s unique “perfume.” This specific floral aroma is comprised of over 30 compounds, especially ketones, fatty-acid derivatives, mono- and sesquiterpenoids. The three most abundant scent chemicals were 1-hexen-3-one, 3-hexanone, and ethyl butyrate. When the impact of these chemicals was tested on mice, it turned out that mice, like humans, find 3-hexanone to have a pleasant smell. The molecule is routinely used in artificial flavoring to produce a sweet fruity grape-like flavor. In addition, 3-hexanone has also been found in some bat-pollinated flowers, so it may be a general mammal attractant. Remarkably, scent cues are particularly important to plants pollinated by small ground-dwelling mammals because these animals are usually around at night when visual cues are less effective (Johnson et al. 2011; Anon.).

In addition to pests, plants have to deal with numerous microbial pathogens such as bacteria, fungi and oomycetes, and viruses in the natural environment. A proper response to pathogens can lead to resistance mechanisms that enable plants to survive. Plants can recognize potential pathogens by detecting pathogen-associated molecular patterns (PAMPs). This recognition activates a defense mechanism. A well-organized communication between the pathogen-invaded plant tissues and non-invaded ones is essential for the timely manifestation of defense mechanisms that limit the systemic spread of pathogens (Shah 2009). Salicylic acid, an important mobile signal, is transported from infected tissue to the rest of the plant body. It activates the systemic acquired resistance, which is a “whole-plant” resistance response that occurs following an earlier localized exposure to a pathogen. Plants not only communicate within themselves about a microbial invasion, they also talk to one another. For example, Tobacco plants warn each other against tobacco mosaic virus attack by releasing methyl salicylate, which is then converted to the protective salicylic acid in uninfected plants (Jacob 2001).

In contrast to harmful pathogenic interactions, there are also symbiotic, advantageous interactions between some microorganisms and plants. Establishment of such a beneficial symbiosis (which literally means “living together” in Greek) is complex. For successful infections, a molecular dialogue between partners is essential (Vadassery and Oelmüller 2009). Among these kinds of interactions, legume-Rhizobium symbiosis is of particular importance in agriculture, because by forming the symbiosis, atmospheric nitrogen can be used to sustain the growth of legume crops, such as soybean, pea, and bean, which occupy 12% to 15% of the land that can be used for growing crops throughout the world (Sugiyama, Shitan, and Yazaki 2007). Rhizobia are soil bacteria that fix nitrogen (diazotrophs) after becoming established inside root nodules of legumes such as alfalfa, clover, peas, beans, lentils, lupins, mesquite, carob, soy, and peanut.

Rhizobia require a plant host, since they cannot independently fix nitrogen (Anon.). Plant roots secrete signaling molecules (e.g. flavonoids) to attract Rhizobia. When Rhizobia sense these chemicals, they colonize around root tissues of the host legume plant. So, the rhizobial infection in legumes is an invasion by invitation (Murray 2011). The attached rhizobia secrete Nod factors, which are perceived by the plant. This initiates a series of events that leads to the formation of nodule, where Rhizobia fix nitrogen. Thus, Rhizobia make legume independent of soil nitrogen and the legume supplies nutrients to the bacteria. In addition, the legume plant supplies one critical component of nitrogenase, which is the key enzyme for fixing nitrogen. It all happens because the plant can talk to the bacteria.

The plant has many interests in being colonized by mycorrhizal fungi. Apart from providing nutrients such as phosphorus and nitrogen, the fungi protect plants from diseases, parasites, and other stresses. Plants even grow as much as 40% more when colonized. In laboratory experiments, carrots that were colonized grew 20 times more than the carrots that were not! In fact, they are such close “friends” that the fungus cannot live without a plant, and between 80-90% of all plants on earth are somehow associated with mycorrhizal fungi. The origin of this incredible friendship is communication (Montréal 2012).

As a result, plants can talk to microorganisms, pests, and mammals, but do they communicate with people? Are they intelligent creatures who can communicate with us? In 1848, Dr. Gustav Theodor Fechner, a German professor, suggested that plants are capable of emotions and that one could promote healthy growth with talk, attention, and affection. An Indian scientist, Sir Jagdish Chandra Bose, conducted experiments on plants in 1900. Bose found that plants grew more quickly amidst pleasant music and more slowly amidst loud noise or harsh sounds (Sir Patrick Geddes and Geddes 1920).

Moreover, according to Royal Horticultural Society, talking to plants helps them grow, especially if the one talking to the plant is a woman. Even though there are lots of divisive experiments done with plants to understand if they can talk to human beings, there is no serious finding about this subject yet. Even if, plant biologists do not currently know how to talk to plants, they strive to comprehend how plants communicate with other organisms in order to use this new and exciting language for improving the resistance of plants against pests or pathogens. Instead of using chemical pesticides, genetically engineered plant defense and communication pathways in crops are a preferred avenue.

Communication of plants with other organisms is such a complex problem. Plants can have a network with so many different creatures. They pass on information to each other or to other organisms that speak other languages. How did they obtain these amazing communication skills? Even the most advanced creatures, human beings, experience problems in communication, how can plants have robust communication systems in a heterogeneous environment?

The next time you hear a strange rustling among your garden plants, maintain distance. They might be having an argument. Plants also talk and they respond to attacks like we do. So, be careful and do not hurt plants as they might even curse or scream to you (Anon.).

Safiye Arslan is a research fellow in the area of molecular biology in Nevada.

References

• Adler, Frederick R. 2011. Plant signalling: the opportunities and dangers of chemical communication. Biology Letters. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3061173tool=pmcentrez&rendertype=abstract.
• Anon. Do plants talk? What are the chances it’s a boy? – USATODAY.com. http://www.usatoday.com/tech/columnist/aprilholladay/2006-07-24-plant-talk-baby-boys_x.htm.
• Anon. jacobson’s organ and the remarkable nature of smell. http://books.google.com/books/about/Jacobson_s_Organ_and_the_Remarkable_Natu.html?id=liKKQgAACAAJ.
• Anon. BBC – Earth News – “Perfumed” parasitic plant lures in pollinating mammals. http://news.bbc.co.uk/earth/hi/earth_news/newsid_9376000/9376474.stm.
• Anon. What is Rhizobia. http://www.bionewsonline.com/y/what_is_rhizobia.htm.
• Anon. Biotechnology: Plantlinguistic: – “Plants Communicate With Each Other.” http://bioinformations4all.blogspot.com/2009/08/plantlinguistic-plants-communicate-with.html.
• Jacob, Tim. 2001. “The science and myths of smell.” EMBO Reports 2 (10): 880. http://www.nature.com/embor/journal/v2/n10/full/embor301.html.
• Johnson, Steven D, Priscilla M Burgoyne, Lawrence D Harder, Stefan Dötterl, and Proc R Soc. 2011. “Mammal pollinators lured by the scent of a parasitic plant Subject collections Mammal pollinators lured by the scent of a parasitic plant.” Society 278 (January): 2303-10. doi:10.1098/rspb.2010.2175. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3119003&tool=pmcentrez&rendertype=abstract.
• Montréal, Jardin botanique de. 2012. “Chatting with a plant’s best friend – Science +” (June 3). http://www.aucoeurdelarbre.ca/en/thematics-texts/thematics-texts-details.php?id=8.
• Murray, Jeremy D. 2011. “Invasion by invitation: rhizobial infection in legumes.” Molecular plantmicrobe interactions MPMI 24 (6): 631-639. http://www.ncbi.nlm.nih.gov/pubmed/21542766.
• Shah, Jyoti. 2009. “Plants under attack: systemic signals in defence.” Current Opinion in Plant Biology 12 (4): 459-464. http://www.ncbi.nlm.nih.gov/pubmed/19608451.
• Sir Patrick Geddes, and Sir Patrick Geddes. 1920. The life and work of Sir Jagadis C. Bose. Longmans, Green. http://books.google.com/books?id=EPtCAAAAIAAJ&pg=PA97&q=”continuous”#v=twopage.
• Sugiyama, Akifumi, Nobukazu Shitan, and Kazufumi Yazaki. 2007. “Involvement of a soybean ATP-binding cassette-type transporter in the secretion of genistein, a signal flavonoid in legume-Rhizobium symbiosis.” Plant physiology 144 (4) (August): 2000-8. doi:10.1104/pp.107.096727. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1949875&tool=pmcentrez&rendertype=abstract.
• Vadassery, Jyothilakshmi, and Ralf Oelmüller. 2009. “Calcium signaling in pathogenic and beneficial plant microbe interactions: what can we learn from the interaction between Piriformospora indica and Arabidopsis thaliana.” Plant signaling & behavior 4 (11) (November): 1024-7. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2819509&tool=pmcentrez&rendertype=abstract.

The phosphate and nitrogen compounds found in the waste material that are released into the environment go through some biological processes and are transformed into nourishing salts for the phytoplankton. When there is an increase in temperature, these salts may cause some of the phytoplankton to grow and reproduce excessively. The toxic materials released by some, and the use of excessive oxygen, are harmful to other organisms.

Another example of pollution is related with algae. When the number of microbial plants called algae reaches one million per cubic decimeter (1 million/dm3) of water, the consumption of oxygen required in order to mineralize, and break-down the organic materials found in the water increases, and therefore a compound of toxins which pollute the water, such as hydrogen sulfide (H2S), are released. This pollution can cause the death of fish and other organisms which live in the water. As a result of the reduction in water quality, an increase in the type of algae called cyanobacteria occurs and the biotoxins that they produce threatens human health.

More than forty types of algae produce various toxins. Some of these toxins damage the human liver, some attack the nervous system (particularly the brain), some can cause allergic skin reactions, and some can even induce cancer. The release of domestic, industrial, and agricultural waste and the high percentage of nutrients (such as nitrogen and phosphor compounds) into the aquatic ecosystem can cause an excessive increase of algae in the waters. This algal bloom in fresh water is referred to as eutrophication. In oceans, it is referred to as red tide because the water appears to be a reddish color. Both present a significant environmental problem.

In low doses humans are exposed to these toxins by the consumption of drinking water. In Brazil in 1988, almost 2000 people developed gastroenteritis over a forty day period due to the consumption of drinking water contaminated by these toxins, and eighty-eight of them died. In South Australia, as early as 1878, many sheep, horses, dogs and other animals died as a result of drinking water from Lake Alexandrina, which was covered by scum caused by an aglal bloom called Nodularia spumigena.

Mussels, a delicacy eaten and enjoyed by many, accumulate large amounts of toxins because they feed on phytoplankton. One study found that in fresh water mussels (Mytilus galloprovincialis) that fed on cyanobacteria, almost 10.7 g toxins per gram of bodyweight was accumulated. This is also the case in marine mussels. It has been determined that these toxins in gradually increased concentrations are passed onto organisms higher on the food chain by consumption. Accordingly, we should always consider the potential risk factors before consuming shellfish.

Biotoxins are released into the water after being broken down by algae. Thus, when an algal bloom reaches high levels, there is an increase in the density of toxins in the water. As these toxins dissolve in the water, purifying the contaminated water requires not only expensive, but also advanced technology methods. Unfortunately, it is impossible to remove this waste in many of the existing refining plants. The toxin concentration in drinking and utility water should be reduced in regions where drinking water is obtained from lakes by mixing it with uncontaminated water, particularly during the spring when the algal bloom occurs. Thus, reducing the amount of biotoxins in the water to a level that will cause minimal harm to aquatic organisms should help to reduce the risks to humans.

Many types of waste released into the environment cause damage, which adversely affect humans. Polluting the environment may be easy, but purifying the environment of this pollution is a very difficult task. Indeed, humans were not created to act irresponsibly and destroy the universe in which they are mere guests. On the contrary, the human is a delicate guest with sublime duties. Protecting the natural resources provided for our needs and utilizing these resources in the most productive manner, without disturbing the balance of nature, is a duty of every human on earth.

References

• Pouria S. de Andrade A. 1988. “Fatal microcystin intoxication in haemodialysis unit in Caruaru, Brazil.” Lancet 352:21-26.
• Carmichael W.W., Azevedo S.M.F.O. 2001. “Human fatalities from cyanobacteria: Chemical and biological evidence for cyanotoxins.” Environ. Health Perspect 109: 663-668.
• Codd G.A., Bell S.G., Kaya K., Ward C.J., Beattie K.A., Metcalf J.S. 1999. “Cyanobacterial toxins, exposure routes and human health.” Eur. J. Phycol. 34:405-415.