- Friday, 20 February 2015 09:54
by Dr. Atta-ur-Rahman
The Chemistry of Love!
Can the opposite mate be attracted and sexual desires aroused chemically? In the animal kingdom this is very common. In humans too, there is growing evidence that certain chemicals may serve as attractants to the opposite sex.
Bees have a very complex system of communicating through release of certain chemicals (“pheromones” or insect hormones) which convey special messages to other bees. Butterflies and moths are so sensitive that if certain sex attractant chemicals are released, the butterflies and moths will sense the sex hormone several miles away (10.6 km recorded). This sensitivity of insects has been exploited by farmers to develop traps which attract all the females to the trap from miles around, thereby eliminating the possibility of breeding.
What about humans? Are there chemicals that will sexually arouse men and women? Women with irregular menstrual cycles, when exposed to the smell of compounds in men’s armpits, had the cycles regularized. A compound (androstadienone) present in the sweat of males was found to increase the levels of cortisol, a stress hormone, in women (The Journal of Neuroscience, 27(6): 1261–5. doi:10.1523/JNEUROSCI.4430-06.2007). Sex drive can be increased by admission of the hormone testosterone in older males. Yohimbine, an alkaloid found in the bark of plants of genus Yohimbe, has been used for the treatment of impotence by increasing genital blood flow in males and enhancing sexual excitement and sensitivity. In August this year a US based company reported positive phase 1 clinical trials of a compound (bremelanotide) when administered subcutaneously for erectile dysfunction, (http://www.palatin.com/news/ news.asp?param=221)
Many compounds have been discovered which act as aphrodisiacs. Some really exotic chemistry underlies the phenomenon of sex in insects, sea urchins and humans ---- the ability to trigger uncontrollable attraction by using suitable hormonal sprays may be around the corner!
Molecular Jet Engines — Within Us!
Imagine a long necklace with some 3 billion beads. Think also that these beads are only of 4 colours. This is the blueprint of life – the four types of beads representing four different molecules called “nucleotides”. It is the sequence in which these molecules are arranged which determines everything about you – be it the colour of your eyes, the structure of your organs or the composition of your cells. Imagine now that there are two separate strands of these “molecular necklaces” arranged anti-parallel to one other. These two strands are connected and held together by certain forces (hydrogen bonds) so that they resemble a long ladder. The ladder adopts a twisted form (the now familiar structure of the helical double stranded DNA). When a cell divides, the twisted ladder uncoils and opens up at an incredible velocity of 30,000 revolutions per minute, much faster than the fastest jet engine! The two strands come apart and new complimentary strands are synthesised for each of the two halves of the ladder. The result : one ends up with two ladders instead of one, and they twist back again at the same fantastic speed----akin to molecular jet engines working furiously but so quietly in our body. A new cell is formed, and all the coded information contained originally in a single cell is now contained in two daughter cells. All this goes on at the body temperature and we do not feel these molecular machines at work. This represents the miracle of life!
On Genome Sequencing and Synthetic Life
The first human genome to be fully sequenced cost about US$ 60 million and was completed in May 2006, although the rough draft was announced in 2003 after 13 years of effort. Due to spectacular advances in sequencing technologies, the sequencing of the entire genome of James Watson was accomplished last year in just 2 months at a cost of US$ 1 million. Machines are under development which may be able to do it in days for under a thousand dollars. A simpler form of genetic analysis which can cost only a few hundred dollars provides information about point mutations in a person’s DNA which are linked to traits and susceptibility to diseases. This may allow us to take precautionary measures before the disease actually occurs.
Spectacular advances are being made in attempts to create life artificially. Dan Gibson and coworkers at the J. Craig Venter Institute in USA reported in Science last year the preparation of the entire bacterial genome, comprising a huge number of 582,970 base pairs artificially (by synthesis) modeled after a bacterium Mycoplasma genitalium.
“Immortal” Human Cells!
Is it possible for the cells that make up your body to continue to live and proliferate long after you have died? Indeed it is! One striking example is that of “HeLa” cells, so named because they were taken from the cervix of a 31 year old African-American lady, Henrietta Lacks in 1951 without her permission when she died of cervical cancer. These cells are still “alive and kicking” today. Some 50 million metric tons (!) of the living cells have been produced in laboratories all over the world, and over 60,000 studies using them published on a wide range of such topics as ageing, cancer, cellular effects of working in sewers, mosquito mating etc. What is so special about these cells is that they multiply abnormally rapidly, as compared to other cancer cells, which makes them very useful in research. The children of Henrietta Lacks first received the shocking news that their mother was “alive” in the form of these cells in 1973. By then the HeLa cells had been taken to outer space and spread worldwide, even contaminating many experiments as far as Russia, because of their extraordinary proliferation abilities.
Henrietta Lacks lives on in the form of her living body cells. Her HeLa cells continue to benefit virology, biotechnology and medical research.
Life — Did the Building Blocks Come from Outer Space?
Our bodies contain proteins which are built up of smaller molecules called amino acids. Amino acids can, in theory, exist in two forms which are mirror images of one another. They would have identical physical properties except for the way they rotate light when it is passed through them. For some unknown reason only one set of mirror images (one “chiral” form) of these molecules exists naturally. This is a huge unsolved mystery about the origin of life ---why has nature chosen only one particular set of molecular building blocks? Life could equally well have evolved from the opposite (mirror image) set but, strangely, this has not happened. This has led to the theory that the molecules of life came from outer space where conditions could have existed to allow one set molecules to be formed.
Last year Zita Martins and colleagues at Imperial College London found the first evidence of extraterrestrial molecules of life. While investigating the composition of a 4.2 billion year old meteorite which fell to earth in Australia in 1969, they discovered that the meteorite possessed two molecules, uracil and xanthine, which make up DNA and RNA. The extraterrestrial origin of these compounds was established from the carbon isotopic ratios. This discovery supports the hypothesis that life began on earth after it was seeded by certain molecules present in meteorites which bombarded our planet about 4 billion years ago.
Is Thought Abstract and Is Intelligence Inherited?
Is thought abstract? Most people would imagine that it is. Not true! The ability of the brain to store knowledge and to think is a chemical process, which can be chemically manipulated. Thus there are anti-depressant medicines which will help to cheer you up if you are depressed, and “truth drugs” which will make you tell the truth even if you do not want to. Atta-ur-Rahman and co-workers working at H.E.J. Research Institute of Chemistry, University of Karachi have proposed a new Theory of Memory ( Pure Appl. Chem., 74(4), 511 (2002), USA).Learning may involve a process of formation of hydrogen bonds in the glycoproteins present in the human brain while forgetting may involve the breakage of these bonds.
Whatever be the basis of memory, one can state with certainty that thoughts have a molecular basis and thus a physically concrete existence.
The brain’s “grey matter“, which contains the processor cells, is heritable. The brain’s “white matter”, which is responsible for providing the connections between processors and which correlates with intelligence, is also heritable. Recently Paul Thompson and co-workers at the University of California have shown that the protective myelin sheath (which governs the quality of the connections between the grey and white matter) is also determined genetically.
So can you improve your intelligence? The answer is yes, within limits, with mental exercises and training as we normally use only a small fraction of our brain’s full capabilities.
Can Diet Enhance Memory?
Can you improve your memory by controlling your food intake? The answer seems to be yes! Eating less improves not only your physical health but also your mental capabilities. In a research finding published in the Proceedings of the National Academy of Sciences (USA), Agnes Floel and colleagues at the University of Munster in Germany have shown that when a group of persons of average age about 60 were kept on a diet with 30% less calories, those on the diet scored 20% higher in a word-based memory test. So take care how much you eat before your exams - dieting may get you those few extra marks that can make all the difference!
On Fireflies and Luminescent Flowers!
We have all probably seen fireflies glowing in the dark. How does this happen? There is some fascinating underlying chemistry involving a compound luciferin. Luciferin combines with oxygen, and light is emitted as a result of this reaction. The same mechanism exists in some deep sea jelly fishes which send out periodic flashes of light in the pitch dark depths of the ocean. A fascinating experiment conducted by some Israeli scientists was to transplant the genes responsible for the production of luciferin into orchids. The result was luminescent orchids which glow in the dark! The time may not be far when you will be able to sit in the evening in your garden surrounded by chemiluminescent roses and other flowers. This indeed is the strange and wondrous world of science!
Obedient Bacteria: Biological Robots!
We are all aware of robots ---- they are widely employed in industry. Much of the manufacturing in the automobile industry today is carried out by robotic machines. Household robots are also being developed which are gradually becoming more and more intelligent. Scientists are working on another exciting frontier of this field----that of biological robots! This involves tinkering with the genetic machinery of biological organisms so that they can perform specific predetermined tasks.
Bacteria, usually regarded as organisms responsible for disease, have already been harnessed for a variety of useful purposes. These include conversion of such raw materials as molasses to citric acid, preparation of industrial enzymes and manufacture of drugs. This however was accomplished with natural organisms. Now “stripped down” bacteria (i.e. genetically altered organisms) are being developed which can act as micro-slaves, (biological robots or “biobots”), programmed to accomplish such tasks as imprinting nanoscale patterns on microchips by secreting certain chemicals along a predetermined pathway. Self-cleaning “living” fabrics are also under development. They are embedded with harmless strains of bacteria that can remove odour from sweaty arm pits as they feed on the sweat and accompanying proteins. Other bacteria can secrete protective coatings that will extend fabric life or secrete chemicals with antiseptic properties which can be used in bandages.
Bacteria are already used to clean oil spills, degrade chlorinated hydrocarbons, and remove toxic metals from the soil. Efforts are now underway to develop genetically modified microbes which can accomplish specific industrial tasks.
Animals---Their Fascinating Sense of Direction
I had a pair of dogs in the 60’s who were constantly bothered by a wild cat in the neighbourhood. One day I had the cat captured, put in a jute bag, locked in the dickey of my car and taken by a circuitous route to Hawk’s Bay at the other end of Karachi where the cat was released. Lo and behold, to my utter amazement, the following morning the cat was back, safe and sound!
Many animals have an amazing ability to find their way around. They include birds, rats and hamsters. Blindfolded and taken to another place by circuitous routes, golden hamsters can return straight home with ease. Geese, toads and spiders also have these skills. How do they do it? Some species have specialized senses that we do not possess and can find their way about using these senses. Migratory birds use the earth’s magnetic field for navigation. Some insects use gradations in the polarity of light to find their way about. Other animals such as rats, mice, monkeys and goldfish have special neurons in their brains dedicated to the sense of direction, allowing them to compute distance and direction with surprising accuracy.
Many animals can travel huge distances using these remarkable navigation abilities. A bird, the Arctic tern, flies about 70,000 km each year from its breeding ground in the Arctic to its winter habitat in the Antarctic. Although it weighs only about 100 grams, over its life time it travels about 2.4 million kilometers which is equivalent to about 3 trips to the moon and back, using its extraordinary stamina and navigation skills.
Mice Born from Stem Cells!
Stem cells found in our body are responsible for repairing damaged tissues and organs. They are part of a powerful internal repair mechanism. Stem cells can be transformed into other specialized cells such as a heart, kidney, muscle or red blood cell. They are thus constantly replacing worn out tissues by fresh tissues. In 1998, scientists discovered how to derive these cells from human embryos and grow them in the laboratories. The use of embryonic materials for producing stem cells was highly controversial and the laws in many countries forbade research in the field. However two years earlier, in 1996, another important breakthrough had occurred when scientists found that it was possible to take specialized adult cells, such as normal skin cells, and “reprogram” them genetically so that they became converted into cells that resembled stem cells (“induced pluripotent stem cells”), (iPS cells). Such cells were first reported from mice in 2006 (Takahashi and Yamanaka, Cell. 2006 Aug 25; 126(4):652-5) and in late 2007 from humans (Takahashi etal. Cell. 2007 Nov 30; 131(5):834-5. and Yu etal Science. 2007 Dec 21;318(5858):1865 ). The use of stem cells to regenerate damaged heart, kidney and other tissues promises to change the way we will treat diseases in the future.
The first live mice have recently been created from mouse skin cells by Zhou etal. of the Chinese Academy of Sciences in Beijing, thereby establishing the potential of stem cells into all the body tissues (Nature, DOI: 10.1038/nature08267). If mice can be born in this manner, so can humans before long!
Shock treatment for Cancer
A technology similar to that used in the “taser stun gun” is being explored for treating cancer. Nanosecond high voltage pulses when applied to cells can cause those cells to destroy themselves, offering a potential treatment for cancer. Such nanosecond pulses have longer lasting effects then the microsecond pulses used in taser guns, the effects of which wear off quickly.
A World Epidemic --- in Bee Colonies!
Something very strange is in the wind. A mystery disease is wiping out a large number of bees in various parts of the world, which could threaten certain types of crops that rely on bee pollination. The bees suffering from an affliction, known as Colony Collapse Disorder (CCD), have their memories affected, so that they are unable to get back to their hives. Some beekeepers in USA have reported the loss of 35-45% of their colonies, and it is thought that the disease seems to be affecting their immune system which results in memory losses.
New hardy bacteria, called “extremophiles” have been discovered on earth which can survive under very extreme conditions, raising hopes that life may have evolved under much harsher conditions than hitherto considered possible on other planets. The South African extremophile bacteria live some 5 miles below the surface of the earth in the South African gold mines, and derive their energy not from surface water or sunlight but from an extra-ordinary source, the radioactive decay of some unstable atoms present in the rocks.
Natural photosynthesis involves the use (by plants, algae and many bacterial species) of sun light to convert carbon dioxide from the atmosphere to sugars. About 100 billion tons of carbon is converted into biomass each year. Some 100 terawatts of energy is thus captured, which is about 6 times the total power consumption on our planet.
Efforts have been made by scientists in the past to develop artificial photosynthetic processes with limited success. Researchers at the University of Cincinnati in USA have developed a process to create a photosynthetic material from a foam comprising enzymes derived from plants, bacteria, frogs and fungi. This foam is capable of converting sunlight and carbon dioxide into sugars. These sugars can then be converted to ethanol and other biofuels.
The idea to use foams came from the study of certain frogs (Tungara frogs) that produce stable long-lasting foams for developing tadpoles. These foams allow excellent penetration of light and air, and enzymes encased in such foams can be used for artificial photosynthesis. The foam is claimed to have several advantages. It does not need soil, and can therefore use sunlight to produce sugars without using soil needed for producing food crops. It is also claimed to be able to convert all the energy from the sunlight captured to sugars, whereas plants use some of this energy to maintain their life functions.
Are Criminals Prisoners of their Brains?
There is growing scientific evidence that hardened criminals possess certain brain abnormalities which make them behave as they do. The argument that the criminal act is due to a neuropsychological impairment is being increasingly used in courts by defence counsels. This can be demonstrated by MRI scans of certain regions of the brain that show that there are some inherent physical abnormalities in the brains of the criminals as compared to those of normal persons, so that the extent of culpability can be reduced (Behavioural Sciences and the Law, Volume l 26, p 85). As the field of neuroscience grows, and the relationships between differences in the physical structure of the human brain with behaviour are better understood, such considerations will become increasingly important in criminal trials.
Test Tube Babies—from a Selection!
Test tube babies are made by uniting the egg from a woman with the sperm of a man in a lab dish. The egg then starts dividing and the early stage embryo is then transferred into a woman’s uterus to develop. The technique is known as In Vitro Fertilisation (IVF). Some clinics, in order to increase the chance of success, implant more than one embryo into the uterus, resulting in the birth of twins, triplets, quadruplets, etc. These babies are often born early and they can face health problems. Scientists have therefore been searching for methods whereby they could select the best embryos for implantation.
Now Renee Reijo Pera and co-workers at Stanford University have developed a new test that allows the best embryos to be picked up for transplantation. An exclusive license has been acquired by a US company, Auxogyn, to commercialise the findings. In the US alone there are some 500 companies offering IVF services and the total world market is estimated to be several million dollars.
Meanwhile, the Nobel Committee announced on October 4, 2010 that this year’s Nobel Prize for Medicine will go to Bob Edwards, an 85year-old British scientist who pioneered this method. The researches were carried out at Cambridge University and the first ‘test tube baby’ Louise Brown was born in northwest England by this procedure on July 25 1978. Since then some four million babies have been born by IVF.
Human Evolution Due to Dinosaur Extinction!
About every 100 million years, our planet is hit by a big asteroid which can change the course of evolution. If we were to be hit by such an asteroid now, most of life as we know it would be wiped out and the few insects, fish and bacteria/viruses that survive would begin the evolutionary process all over again.
About 200 million years ago the lush green earth was inhabited by reptiles, many of which, such as the dinosaurs, were huge in size. This reptilian era lasted some 160 million years. Then 65.5 million years ago a huge asteroid, about 10 kilometres across, slammed into Mexico. The result was a global catastrophe. The blasted rock layers released a huge amount of carbon and sulphur containing gases. Fires raged and darkness descended as the resulting dust blocked sunlight from reaching the earth. Acid rains followed and the earth cooled. Most life was wiped out, including reptiles, birds and plants and only about half of the most resilient mammals survived. The extinction of the dinosaurs and many other life forms changed the course of evolution.
The surviving mammals were generally smaller in size, versatile in their movements, could breed fast, and escape the fires and acid rain that ravaged the earth. There was a new burst of evolutionary creativity in this changed environment some 10 million years later, finally leading to humans, as is evident from the ‘molecular clock’ studies which are based on the reconstruction of the evolutionary tree from the study of the genomes of related species. We may owe our civilisation to the extinction of the dinosaurs!
Grow Muscles --- in the Laboratory!
We all know how hard it is to develop muscles. It involves months, if not years, of hard exercise, perseverance and patience in the gym. Scientists at the Eindhoven University of Technology (TU/e) in the Netherlands have developed a method to develop muscle tissue, complete with blood vessels, through a process of bioengineering. The muscle tissues need to be organized in such a manner so that they are aligned in the same direction, in order to produce strength, and each muscle should have an appropriate supply of blood vessels so that oxygen and nutrients could be transported to it. Previous attempts had failed as the tissues produced were disorganized.
The TU/e team succeeded where others had failed by using stem cells and blood vessel cells to grow the tissues. The alignment in one direction was achieved by fastening the pieces of tissue in one direction using Velcro. The resulting tension in the growth process resulted in the muscles and blood vessels being properly aligned, rather than growing in a disorganized manner. The scientists hope to apply this technique for growing muscles for patients who may have lost muscle tissue by accident, injury or in surgeries involving cancerous tumors.
New Form of Life Discovered!
A completely new form of life has been discovered by scientists working at NASA in USA which uses arsenic instead of phosphorus in the living process. For life to exist certain elements have been assumed to be necessary: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. The discovery of a living organism that has learned to live without phosphorus is therefore an earth shattering discovery. Phosphorus is present in DNA which is vital to life. The bacteria discovered by NASA scientists learned to replace phosphorus with arsenic and were still be able to live.
The bacterium, code named GFAJ-1, was isolated from Mono Lake in USA by Felisa Wolfe-Simon. It was then grown in a medium with very little phosphorus but high content of arsenic. Analysis showed that the bacterium was remarkably capable of incorporating arsenic instead of phosphorus in its DNA backbone.
If the work by NASA scientists is found to be correct, it would mean that life may have evolved on other planets in our universe in completely different ways than it has on earth, by utilising other elements.
Turn into Juicy Mushrooms --- after Death!
Do you want to turn into a bunch of juicy mushrooms after your death? A suit invented by artist Jae Rhim Lee will accomplish that smoothly. The artist has been experimenting with environmentally friendly ways in which bodies may be buried so that they do not produce toxic materials when they decompose. The special suit is embroidered with a netting of one of different types of mushroom spores. So you have a choice too, which mushroom you would like to turn into! The corpse is wrapped in this suit and is then embalmed with special slurry containing more spores and important minerals. The combination works wonders. The body is soon eaten away, and the organic matter breaks down into nutrient rich compost that feeds the mushroom spores and also enriches the neighbouring soil. In time some excellent mushrooms will grow out of the dear departed ones, who may then end up on someone’s dining table and be a source of pleasure and satisfaction.
The “Infinity Burial Project” has attracted a society around the concept --- the Decompiculture Society --- that is devoted to propagating such “green burials”.