Monthly Archives: May 2013

Vidurashwatha: The forgotten Jalianwalla of South

Temple in the village

Just like April 13, 1919 is etched in the minds of Indians for the Jallianwala Bagh massacre, April 25, 1938 is one day that the people of Vidurashwatha village in Karnataka find hard to forget.

Vidurashwatha, a nondescript village in the Kolar district of the state. It gets its name from a banyan tree (ficus religiosa) said to have been planted by Vidura. Vidura is known for being staunch supporter of truth. When all the great men like Bhishama, Dronacharya sat helpless and looked on mutely the excesses of Duryodhana, he was the one to protest and chastised these elders to do something to stop Duryodhana’s excesses. He sided with truth and earned the wrath of Duryodhana.

Banyan trees are considered very auspicious throughout India. Siddhartha became Buddha while meditating under the Bodhi tree which was a Banyan tree. The tree belongs to fig family. It is a very long lasting tree.

However, the village has more than just its mythological inheritance to be proud of. It was here, 75 years ago, that a freedom movement was bravely fought and brutally suppressed.

At a time when India’s freedom struggle was at its peak, a group of villagers, taking out a peaceful procession, were indiscriminately fired at by the police – a massacre that sent a chilling reminder of the Jallianwala Bagh massacre that had happened just 19 years ago, proving that British here did not had any qualms about what they did. No repentance and repeated the crime again.

The group was headed towards a maidan (ground) near the village temple for a non-violent flag Satyagraha. However, as they congregated and rent the air with cries of Vande Mataram, the police opened indiscriminate fire killing 10 people.

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Color Changes in Chameleons

We have been told that chameleons change their color to conceal themselves by blending in with their surroundings. In fact, a person who is changeable or inconstant in behavior is called chameleon. It has been proved that the facts are something else. And it is a myth. .  Most of the reason chameleons change colour is as a signal, a visual signal of mood and aggression, territory and mating behaviour.

The chameleons are master molecular scientists. Their skin has transparent layers in which different color compounds are tucked away. These specialized cells store the different color compounds and these cells are called chromatophores. They contain various pigments.  These are xanthophores, containing particular specialised pigments that have a yellow colour.  Beneath that are pigment cells which are called erythrophores which have a red colour in them.  Beneath that, another layer of cells called iridiphores have a blue coloured pigment called guanine, which is actually also used in making DNA.  And underneath that is another layer of cells called melanophores which have a brown pigment – melanin – in them.

As such these pigments are confined to sacs. Depending on the signals from the brain, pigments are leaked and depending on the amounts released, mixed colors are formed. This is like artist mixing the different amounts of colors in the color palette. So if you mix red and yellow, you get orange for example, and this is how chameleons do this.  They mix different contributions of these chromatophores.

So a calm chameleon is a pale greeny colour.  When it gets angry, it might go bright yellow, and when it wants to mate, it basically turns on every possible colour it can which shows that it’s in the mood.  This is not unique to chameleons.  Other animals also have these chromatophores. Cuttlefish are another very elegant example of how this works.  So it’s not so much to do with camouflage.  It’s more to do with communication.

Yogurt

Yogurt is the fermentation product of milk. In India,  it is part of food consumed by the village people. Buttermilk is made from it and in summers it gives refreshment and energy. It has a cooling effect and promotes digestion because it contains probiotic-the “good bacteria” in addition to Calcium, proteins.

As in most of transformations, the process of converting milk into yogurt is carried out by bacteria. Yogurt forms when bacteria ferment the sugar lactose (C12H22O11) into Lactic acid (C3H6O3).

Lactose

Lactic Acid

Although Lactic acid is a weak acid, it is strong enough to lower the pH (or make more acid) causing the proteins in milk to coagulate. The main protein in dairy milk is casein. The acidity gives yogurt its tangy flavor, while the coagulated proteins result in a thickened, creamy texture. Several types of bacteria can ferment lactose. Yogurt cultures may contain Lactobacillus delbrueckii subsp. bulgaricus, other Lactobacillus strains, Streptococcus thermophilus, and bifidobacteria.

You can make yogurt from any type of milk. Although most yogurt is made from bovine milk (e.g., cow, sheep, goat), the fermentation process works on other types of “milk”, as long as they contain a sugar for the bacteria to ferment and protein that can be coagulated. Yogurt can be made from soy milk, coconut milk, and almond milk.

The first time you make yogurt, you need a starter culture as a source of the bacteria. You can use ordinary store-bought yogurt with active culture or you can use freeze-dried yogurt starter. Milk is inoculated with the stored bacteria culture which begin to multiply and convert sugars into Lactic acid. The bacteria work optimally at 100°F (38°C). So the temperature should be maintained as close as possible to this temperature and milk undisturbed.

Vegetable Dyes

Third most important group of dyes is the Vegetables dyes group. Although they can be obtained from almost any plant but most important were madder, woad, and indigo.
Madder (Rubia tinctorum),

Madder Plant

a bright red dye, comes from a plant of the same name also known as “dyer’s root.” Though its origin is lost in antiquity, it was used to dye the wrappings on Egyptian mummies. It is said that Alexander the Great used madder to help him defeat the Persians in 350 B.C. He had many of his soldiers dye their cloaks with splotches of red and stagger onto the battlefield. As the jubilant Persians fell on the “badly wounded” enemy, they were soundly defeated. Madder appeared in Europe in the seventh century and was the dominant red dye for more than 1000 years. It provided the red for the famous British redcoats during the American Revolution. The chemical responsible for the color is alizarin.

Woad, a dye from the European plant Isatis tinctoria, has been found on some of the most ancient textile fragments ever unearthed.

It was used to dye the robes of the high priests of Jerusalem in Biblical times, but it was in Europe that it was extensively cultivated. The dye was obtained by first air-drying the woad plants and grinding them to a powder. The powder was then moistened, placed in a warm, dark place, and stirred frequently. Several weeks of fermentation produced a black paste, from which a blue dye was extracted. The European woad plant had indigo as its main chemical constituent. Woad was the principal European dye for centuries, and dyers became quite skilled at mixing it with other dyes to obtain new colors. Saxon green was the result of dyeing a fabric with woad, then over dyeing it with weld, a yellow dye from another plant. When woad was over dyed with madder, a purple shade resulted.
Indigo, from the plant Indigofera tinctoria, is much richer in the indigo molecule.

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This dye worked its way from India to Egypt, the Holy Lands, and eventually Europe, where it arrived around 1200 A.D. Its introduction was bitterly opposed by woad growers. Many laws were passed against use of the “devil’s dye,” and it was widely believed to harm both the cloth and its wearer. So successful was the anti-indigo lobby that the dye did not become established in Europe for more than 500 years. Then King George II chose indigo for the British naval uniform, giving the world “navy blue” forever after. Indigo was one of
the few natural dyes of commercial importance to America. In 1744 Eliza Pickney grew indigo from seeds her British army officer father brought from the East Indies to the colonies. Later, the enterprising young woman persuaded plantation owners around Charleston, S.C., to grow indigo and set up the Winyah Indigo Society. This cooperative shipped great quantities of the dye to England, until introduction of synthetic indigo destroyed the market for the natural product. Today indigo has been largely replaced by other blue dyes, though it is still used as the dye of choice for coloring blue jeans.

More of Dyes: Animal Dyes

As told previously, the dyes were made from the minerals and natural rocks. The examples of these were Ochre Dyes which are the iron oxide compounds.

Second group of natural dyes is the animal group. One of the earliest and most important of the animal dyes called Tyrian Purple was obtained from several species of snails found along the shores of the Mediterranean.

Plicopurpura pansa

It was discovered by the Phoenicians about 1500 B.C. and became, for the next 3000 years, the most important dye of the civilizations that rose and fell in the area. The demand for mollusks rose rapidly as dye factories sprung up along the Mediterranean and west African coasts, and Phoenician traders carried the dye to Spain, France, and Italy. According to Pliny the Elder, the dye was extracted by crushing the shellfish and boiling them in salt water for ten days. Cloth was dipped in this solution, then exposed to sunlight. Due to the photosensitive nature of the coloring molecules, the yellow color changed to greenish-blue, then finally to purple. The Roman emperors prized the dye and decreed that only members of the royal family could wear clothing colored by it, hence the expression “born to the purple.” Among those who wore Tyrian purple were Alexander the Great, Julius Caesar, and Cleopatra.
Other animal dyes were obtained from insects. Kermes was a scarlet dye obtained from Coccus ilicis, a tree scale that lived on oak. Moses mentioned its use in Egypt, and other writers referred to it as captured booty in 1400 B.C. Kermes varied in color from bluish-red to brilliant scarlet depending on the mordant used. A mordant is cation of metal which forms a link between the clothe and the dye and helps adhere permanently to the clothe. It can also change the color of the dye altogether. One example of the mordant is Alum which contains Aluminum ions in trivalent state.

A dye very similar to kermes was discovered by Mexican dyers around 1000 B.C. Cochineal is derived from another scale insect, Dactylopius coccus, that lived on cactus. The insects were collected by hand, about 200 pounds per acre of cactus, and dried in the sun. The dried insects resembled rust-colored grain seeds and gave scarlet dye when soaked in water. The Spaniards learned of cochineal in 1518 A.D. and brought it to Europe, where it rapidly replaced kermes. The scarlet obtained with a tin mordant is particularly beautiful and was used until 1954 to dye the uniforms of the British Brigade of Guards uniforms.

Dried Insects

Fascination to Coloring their World

“Thou shalt make the tabernacle with ten curtains of twisted linen, and blue and purple and scarlet…(Exodus 26:1)”
These lines from Holy book “Bible” show the human desire for colors. It has been always been fascinated with color. The competitors of our forefather “homo sapiens”, prepared their dead for burial by coating their bodies with red ochre, which is actually Ferric oxide. After them, Cro-Magnon made cave paintings using for colors yellow and red iron oxides, black manganese dioxide and white clays. These are natural material available as rocks and salts for tens of thousands of years. This continued until the invention of weaving and clothes.

Pigments had been made by combining colored minerals with a vehicle, such as oil or mud, that would adhere to a surface. When the paste-like pigments were applied to fabric, the cloth became stiff, and the coloring material soon washed or fell out. Pigments wouldn’t
work—cloth could only be colored by dyes, organic molecules that bond directly to the textile. So colors which adhered to cloth and became insoluble afterwards. And also they should be soluble in the water. This was usually achieved by adding chemical compounds like alum which contain metallic ions which act as binder for cloth and dye.

Hibiscus: Showy Red Flowers

The summer has set in the earnest in North India now. The spring flowers are withering away and soon grass also shall be discolored. The land shall become parched and dry. It is still good here in the morning.

These days Hibiscus shrubs are in full bloom and laden with bright red color flowers. Many people are seen plucking them for offerings before the Gods in their homes and temples. They think Gods are confined to the places where we have placed them and cannot go out and watch and appreciate their own creation themselves. I think they won’t recommend plucking the flowers.

Anyway, as usual I went for walk slightly late. It was seven of clock and Sun was up for sometime now. The buds of these flowers opened gloriously to welcome the sun and spread beauty all around.

Hibiscus is a genus of mallow family, Malyaceae. It is quite large, containing several hundred species that are native to warm-temperate, subtropical and tropical regions throughout the world. Member species are often noted for their showy flowers and are commonly known simply as hibiscus, or less widely known as rose mallow

It is favorite flower of Goddess Kali and Lord Ganesha. In Assam India, the shrubs grow very large and voluminous and each tree may bear hundreds of flowers. The leaves of the plant are said to be beneficial in many diseases. Hibiscus tea is also good for health.

I took some pictures of the showy flowers and I am putting them here.

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Annatto (Bixa orellana L.)

Mysore is a famous city in Karnataka. It has a rich history and also pleasant climate. Due to this there are always flowers everywhere. It is city of gardens. There are numerous monumental buildings and temples. Near by is the Sangam where Cauvery river segments again merge. Also the famous palace of Tipu Sultan and his fort which was surrounded by a deep moat on all sides. But he was killed there.

I came across these shrubs first time in the campus of CFTRI Mysore. The institute is doing  research to increase the yield of flowers and seeds. Seeds are used as natural dye for food coloring. Seed coating contains carotenoids which impart red color and terpenes give the scent.

The trees are natives of South America. Small numbers grow in Karnataka and adjoining states of South India. Flowers come in bunches and have tough spiny hairs. When you open the the flower case, inside are seeds and your hands will be colored red with the dye. South Americans used it for many purposes like lipstick, body painting and medicine. I took some photos.

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Seeds inside the flower

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Shrub with flower

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Bunches

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Optical Isomerism

Everything is identical about these twins. Number of atoms, type of atoms are same. Only difference is the spatial arrangement of atoms or groups of atoms attached to the carbon atoms. There is one more trait of these twins-they are mirror images of one another. They are called stereoisomers. Stereo means spatial.

There is a slight differences in the reactivity of these members. One very interesting property of these molecules is that they rotate the light passing through their solution in equal and opposite directions called Levo and Dextro.

When such compounds are synthesized in the laboratory, we obtain both isomers in equal amounts and there is no optical activity because effect of one type isomers is nullified by the effect in opposite direction.

But in nature, synthesis of macro-molecules like carbohydrates, lipids and oils by the biological enzyme driven reactions we exclusively obtain only one kind of isomers-mostly levo-rotatary. This is due to enzymes which are proteins and very specific catalysts whereas industrial catalysts are surface active and both isomers are manufactured in equal amounts. Special techniques are required to separate them into pure Levo or Dextro isomers. Due to this reason the cost of these isomers increases manifolds. It has been found that some diseases respond to specific isomers. Such medicine are called stereo-specific medicine.

Is there life on Mars? Again Microbes hold the key

Earliest life of single cell evolved into 3 branches having distinct traits. The branches further subdivide into more branches on the evolutionary tree of life called Phylogenetic tree of life. The first three branches are called Bacteria, archaea and Eucaryota.

450px-Phylogenetic_tree

As we can see in this tree, there is a member of archaea family with the name Methanogen. This microbe holds the answer for presence of vast quantities of methane which is trapped inside the ice cages called methane hydrates. These hydrates are found on Earth in the permafrost regions having very low temperatures or under the deep sea floor. Water molecules arrange themselves into octahedral cubes in which molecules of many compounds can fit into them. These are called clathrate compounds. These structures are very fragile and as soon as the overhead pressure is reduced or temperature increases, the structure crumbles and gas is released. So special technology is required to produce the methane from hydrates. In US, carbon dioxide was pumped into the hydrate layer. It substituted into the cages releasing the methane free. It served two important purposes. First the production of fuel gas methane and sequestration of unwanted carbon dioxide. These microbes use carbon dioxide and hydrogen to make their food and also generate methane and water. These microbes are very enterprising. They can use alternative sources of carbon like acetates which are the products formed by another kind of bacteria by breaking the macro-molecules present in the buried organic matter, for their food. One thing these tiny beings hate is oxygen. They work in anaerobic environments like deep buried locations.

Now this microbe is being held responsible for the methane gas found on Mars indicating that there is life on the planet. It means Mars is not a dead planet. Professor James Kasting said if there is anything alive on Mars at this time in its history, it would probably be some form of microbial life living deep beneath the planet’s surface. Perhaps the most likely form of microbial life is a type of bacteria known as methanogenic bacteria, or methanogens for short. The CO2 needed by the methanogens could presumably come from the atmosphere. The H2 could come from chemical reactions between water and certain types of rocks, specifically magnesium- and iron-rich basalts. Such rocks are found on certain parts of the seafloor today on Earth. When they react with water, they form minerals called serpentine minerals. In the process, hydrogen is produced. The reaction that produces methane is thermodynamically favorable, so Methanogens could use the energy released by this reaction to drive their metabolism. Microbes can make many reactions happen at much lower temperature by changing the path of reactions through enzyme catalysts which these microbes synthesize.