Vibrio cholerae

The World’s Waters Are Rising – but by How Much, and Where?

Countries that are more vulnerable to vagaries of the climate, such as India, also lack the more precise data that could help them plan better.

Earlier this year, climate activists held a funeral for the Okjökull glacier. Its tombstone, the first of its kind, lies on top of a volcano in Iceland, where the ice sheet has been melting at an unprecedented rate. Indeed, if all the ice in Iceland melts, it could raise sea levels around the world about about five feet. And by the end of this century, as more glaciers recede and melt, sea levels could rise by two full metres. That’s about the height of a door.

Recently, Scott Kulp and Benjamin Strauss, two climate scientists from Climate Central, an American nonprofit organisation dedicated to climate research, identified areas that are most vulnerable to projected sea-level rise by 2050 and 2100. They released maps showing parts of Mumbai, Chennai and Kolkata, and other South Asian cities, going under water in the next three decades, suggesting around 300 million people are vulnerable if humankind continues to emit more carbon.

This is about three-times as many people as estimated to be vulnerable in an older model working with the same emission trends.

The significant mismatch arises from how scientists assess land elevation. A more precise prediction requires more precise elevation data. In the early 2000s, scientists obtained the numbers from NASA’s Shuttle Radar Topography Mission (SRTM) to approximate flood risk in coastal areas. “But SRTM data has flaws,” Kulp told The Wire. The technology can’t distinguish trees from buildings and other land features, so the reported average elevation of an area can be vastly different from reality. Errors could run as high as 2 m in low-lying coastal areas.

A more precise way to calculate land elevation is by using light detection and ranging (LIDAR). In a LIDAR-based land survey, scientists attach a laser to a plane, drone or a helicopter and beam light to the ground. The reflected signal indicates how the land rises and falls as the aerial vehicle moves over it. On the flip side, LIDAR is costly and so most Asian countries – whose economies are more vulnerable to vagaries of the climate – don’t have LIDAR data.

Also read: The Struggle to Track Global Sea Level Rise

To work around this, Kulp and Strauss used machine learning. They trained a neural network to identify flaws in SRTM data for the US coast by comparing it with more than 50 million LIDAR data points from the same area. Once the network had ‘learnt’ how SRTM and LIDAR data matched up, they converted SRTM data from around the world into more precise digital elevation data, called coastal DEM, where they estimated the errors were of the order of 10 cm or less.

And when the duo overlaid the sea-level rise model onto the coastal DEM, they found that older models had underestimated flood risk. According to the coastal DEM, they found that without coastal defences, 360 million people would be vulnerable to flooding by 2100 if sea levels continued to rise as the models predict.

Kulp and Strauss also stressed that this would be the case even if all countries stuck to the terms of the Paris Arrangement. If economies don’t cut back on carbon emissions and if the Antarctic ice sheet starts to wear off, 480 million people will become vulnerable to flooding by 2100.

The carbon dioxide that we release into the atmosphere traps heat, driving global ~~warming~~ heating. Historical data shows that global sea levels have been rising more quickly since humankind started burning coal and petroleum as fuels. Between 1900 and 2000, the average sea level rose by about 1.7 mm each year. After 2000, it jumped to about 3 mm/year. Scientists recorded a similar trend for the Indian Ocean – except in the Northern Bay of Bengal, where sea levels rose by 5 mm/year between 1948 and 2010 (as estimated in 2015).

A section of the map showing parts of land at risk in a ‘bad luck’ scenario by 2050. Map: Climate Central

But the claim that certain neighbourhoods within cities could submerge doesn’t hold water.

According to the maps published along with the duo’s paper, many areas in Mumbai, Kolkata and Chennai could go under by 2100. However, many of these areas also appear to be about 8-10 m above sea level.

Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology, Pune, agrees that the new land elevation estimates are better on a global scale and that there could be uncertainties in the data for Indian cities. “Generally, the uncertainty is above 1 meter, which is larger than the estimates of sea-level rise. But to be certain, India needs a better risk assessment analysis for its coastline,” he said.

Kulp agreed that coastal DEM is more accurate over larger areas than in smaller ones, like cities versus neighbourhoods. He said this is why scientists are talking about flood risk on global and national scales (instead of about the fates of Trombay, Besant Nagar or Siripuram).

These predictions are also limited by the fact that they don’t account for embankments and defence structures that governments have erected to protect the coast from high tide lines. According to the paper, about 110 million people in the world and about 17 million people in India are already living below these lines.

Also read: Bengal’s Diamond Harbour Records Faster Sea-Level Rise Than Other Indian Ports

But Kulp flips the threat on its head to find a silver lining: “Our results give hope that living with high-tide lines is doable” – although if the sea level rises further, more people could be exposed to extreme storms and flooding.

For example, some parts of Mumbai have always been at or below sea level, so a typical worst-case scenario when the sea level is higher would be floods due to extreme rains at high tide. “Such events, called compound events, have the potential to submerge large parts of Mumbai, at least for several days,” Koll said.

And if seawater moves further inland, it can damage soil considered useful for agricultural and even facilitate the spread of disease. In 2015, doctors in Bangladesh were able to associate the spread of cholera with sea-water intrusion. In another analysis published the same year, scientists reported that “suitable areas for Vibrio cholerae” – the bacterium that causes cholera in humans – are “predicted to increase under future climate”, including in coastal parts of eastern India and Latin America.

“Through this study, we want to put pressure on economies and countries to take note of the problem and understand the importance of coastal elevation data,” Kulp said. He, and others, argue such data will help countries assess risk more realistically and plan better for extreme events.

“Another way to look at the study is to realise that cutting back on emissions will help three-times more people,” he added. “And that investing in green technology is three-times more justifiable.”

Sarah Iqbal is a freelance science writer.

Chromosomes Have A Lot to Talk About – Here’s How They Do it

The two chromosomes of cholera bacteria were shown to communicate with each other in fascinating ways to make sure their DNA replication happens in sync.

An installation depicting chromosomes at the Grande Galerie de l’Evolution, Paris, December 2015. Credit: Herman Pijpers/Flickr, CC BY 2.0

The life cycles of cells whose DNA is packed into a single chromosome, like 90% of bacterial species, is relatively simple. But in cells which have multiple chromosomes this gets more complicated. Here, the individual chromosomes within a cell have to ensure that each of them replicate once and only once before the cell splits into two. The signalling molecules and mechanisms responsible for this are still largely unknown.

Higher organisms, called eukaryotes, have a set of regulator molecules that make sure all the chromosomes replicate and segregate before the cell cleaves. However, these molecules are not chromosome-specific. On the other hand in bacteria like Vibrio cholerae, which has two circular chromosomes, each chromosome has different molecules that initiate and regulate replication.

Despite this degree of independence, the two differently-sized chromosomes – the primary chr1 is almost thrice as long as the secondary chr2 – time themselves such that they finish replicating at the same time, every single time! This observation strongly suggests that there is some inter-chromosomal communication in place here. Now, for the first time, scientists from France and Denmark have found evidence of such a mechanism.

Deconstructing cholera bacteria

The primary chromosome in V. cholerae, chr1, contains most of the important genes that take care of cellular function and toxicity. The smaller chr2 also has essential functions like metabolism and heat shock. Replication of chr1 initiates when a molecule called DnaA binds to a point on the chromosome called ori1. A little later, replication of chr2 commences at a point on it called ori2 – this time triggered by another molecule RctB. This delay in chr2 replication initiation seems engineered perfectly so that the two chromosomes complete replication simultaneously and the cell can begin cleavage to produce two daughter cells having a full set of genetic material each.

Ole Skovgaard from Roskilde University, Denmark, explained why this is important: “The bi-partite genome organisation in the Vibrio-related bacteria make them more competitive than they would be with their entire genome organised in a single chromosome; the timing of the cell cycle with synchronous termination add to this competitiveness, possibly in several ways… disturbances of the cell cycle will reduce the fitness in the wild.”

A perfect understanding

Skovgaard and a team of scientists from the Institut Pasteur, Paris, describe how chr2 monitors the replication status of chr1 to time its own replication in a paper published on April 22 in the journal Science Advances. Crucial to this, they found, is a region on chr1 they named crtS that the chr2 initiator molecule RctB binds with to enhance chr2 replication. Chr1 replicates along its circular path and the moment the crtS region is covered, RctB molecule is activated and replication of chr2 is triggered soon after. It also appeared that there was physical proximity between crtS on chr1 and ori2 on chr2 during the cell cycle. In this way crtS acts as a timer region and seems to be a way via which chr1 could communicate to chr2 that the time to start is now.

To confirm its role, the scientists created bacteria with a deleted crtS region. They found that this resulted in severely impaired growth and filamentation and DNA damage. Interestingly, they noticed that a few cells escaped this fate. “They did this through a fusion between chr1 and chr2. Now replication of chr2 will piggyback on chr1 and the cell will recover,” explained Skovgaard.

In addition, the scientists also conducted a 200-generation evolution experiment where crtS-deleted mutants were cultivated and observed for 200 generations. The idea was to find out what kind of mutations were developing in the mutant cells that would allow them to compensate from the crtS loss. “We found that the evolution experiments led solely to mutations in the gene for RctB,” said Skovgaard. “This further strengthens our idea that activation of RctB by replication of crtS is crucial for initiation at ori2. The RctB mutants are likely… independent of crtS replication-activation.”

A novel mechanism

A 2014 study by Baek and Chattoraj first described the possible role of such a site (they had not named it crtS yet) on V. cholerae’s chr1, though they reported that the role of the site was much more modest. The team involved in the current study chalk down the differences in the two observations to the compensatory mutations that develop, making it appear that crtS loss is not crucial to the cell.

This is the first time that such a checkpoint mechanism – where active replication of a short DNA sequence is sensed and the signal is sent to a different process – has been identified in bacteria, but Skovgaard believes that it’s only a matter of time before more cases are spotted. “This novel mechanism is an elegant and cost-effective way for secondary chromosomes to benefit from the already well-adapted replication regulatory system of the host main chromosome,” write the authors.

In an era where research teams around the world are trying to build a cell from scratch, knowledge about such finer aspects of cellular control could be a boon. “We envisage many different ways to use such a mechanism,” they conclude.

How Viruses Engineer their Way to Bringing Disease, and Also Life

In a manner not too different from societies and cultures of today, the genetic material of most organisms is also a mosaic, containing genes and other elements of foreign origin.

This article is the first of a two-part series on viruses and bacteriophages. The second part will be published on December 4.

Viruses are a bigger part of our lives than we think, having infiltrated the DNA of many creatures during their evolution. Credit: slushpup/Flickr, CC BY 2.0

Societies are mosaics of diverse ideas. Indigenous customs and practices of one society intermingle with the hues of others, and influence each other, if not by direct contact then via fluid mechanisms of long-distance communication. This is a truth that many of us realise, and it will not be unfair to say that anyone who believes in the exalted purity of his or her own society or culture is being delusional.

In a manner not too different from societies and cultures of today, the genetic material of most organisms is also a mosaic, containing genes and other elements of foreign origin. External sources of DNA are forever finding their way into the genetic material of most organisms, and at times influencing the characteristics and further evolution of the host. This we refer to as horizontal gene transfer: a form of “natural” genetic engineering.

This happens to be a major source of evolution of bacteria into agents of disease, and notably into those resistant to treatments with antibiotics. Despite the regular exchange of ideas, each culture retains its unique identity; similarly, in spite of extensive horizontal gene transfer, every organism maintains its core characteristics while constantly adding new capabilities.

The case of cholera

A major source of mosaicism in the genetic material of bacteria, and to a lesser extent of plants and animals, are creatures called viruses.

Viruses are tiny. Hundreds of viruses can be comfortably packed inside a tiny bacterium, a million of which can be lined up end to end on a metre-long scale. That means viruses are really tiny. We know viruses as the cause of numerous illnesses, from minor irritants such as that nuisance common cold to significantly more serious matters such as swine flu, dengue, chikungunya, hepatitis, AIDS and the Ebola hemorrhagic fever. These tiny critters are genetic engineers, making otherwise harmless bacteria nasty adversaries of human life, besides conferring benign properties on many forms of life. (In the sequel to this article, we will see how the discovery of viruses that attack bacteria as part of a perpetual war of the microbes enabled the birth of molecular genetics.)

An infectious disease that most of us would have heard of is cholera. This is a widespread water-borne disease, caused by a bacterium that goes by the name Vibrio cholerae. An infectious disease outbreak that spreads across a wide geographical area is often referred to as a pandemic, and the world has seen seven cholera pandemics over the last 200 years, which together have killed well over a million people and caused suffering to many more. Today, deaths due to cholera are relatively rare but one can imagine the havoc this disease would have caused in the 19th and the early 20th centuries. The causative agent of the disease was discovered twice in Europe, presumably independently, in the second half of the 19th century.

The mechanism of the disease process was discovered in India by a doctor from Calcutta called Sambhu Nath De in the mid-20th century. He showed that the disease involved permeation of the intestinal membrane, which results in fluid leakage and loss of essential minerals. It is a quirk of fate that De never got the Nobel Prize, but there have been others across the world who, in the opinion of many, deserved to win this coveted prize but never did.

Anyway, more relevant is De’s discovery that Vibrio cholerae released a molecule into its environment, which was toxic to intestinal cells. This was the discovery of the cholera toxin (CTX), the protein agent.

What makes this bacterium a devious perpetrator of such a debilitating disease? In general, the question of what makes a pathogen a pathogen often gets into deep debates on evolution and why any organism should evolve to cause disease. We’ll stay away from these debates here but mention that the toxin that allows Vibrio cholerae to damage human intestinal cells has viral origins. Yes, this is not part of this organism’s “indigenous” genetic material but is a property that is carried by the genetic material of a virus, which at some point in recent human history integrated into the chromosome of a Vibrio cholerae ancestor that probably could not quite cause cholera.

This insight into the evolution of the cholera-causing bacterium came about only 20 years ago, in a publication by Harvard-based scientists Matthew Waldor and John Mekalanos. A virus turned out to be a genetic engineer providing what was probably the decisive event in making a bacterium an agent of disease.

The causative agent of cholera is not the only bacterium to have been engineered to become a disease-causing organism by viruses. Other examples include some varieties of the bacterium Escherichia coli (E. coli), which causes severe food poisoning resulting in dysentery that can be fatal. In this example, the ability of the bacterium to produce a toxin called the Shiga toxin, which attacks human cells by destroying their protein production machinery, is conferred by the integration of the DNA of a virus into the bacterial chromosome. In the bacterial pathogen dubbed Staphylococcus aureus, the drug-resistant version of which is popularly referred to as MRSA, the capability to manipulate the human immune system is typically a result of the presence of a certain viral DNA in the bacterium’s chromosome. There are many such examples that have been described in research papers and books.

We have also come to realise, through a certain type of genetic analysis called metagenomics, that there are many cases of viral DNA carrying determinants of antibiotic resistance and which could contribute to the making of superbugs, a final frontier for modern medicine. The public health problem caused by antibiotic resistance has found significant press space in recent weeks, and I’ll cover some aspects of the science behind this next month.

There are superpowers, too

Viral DNA integrated into host chromosomes is not all about conferring virulence and antibiotic resistance. The viral DNA in the chromosome of even the benign variant of E. coli enables the bacterium to counter certain stressful environmental conditions beyond antibiotics, including survival under acidic conditions and exposure to highly reactive and detrimental byproducts of chemical reactions involving oxygen. Viral DNA integrated into the chromosomes of bacteria that ferment sourdough can code for enzymes that degrade complex carbohydrates (into forms that can probably be utilised by these bacteria as nutrients and multiply faster).

We know from school that certain bacteria called Rhizobia help fix atmospheric nitrogen into usable forms. This ability appears to have been horizontally acquired, and the DNA encoding this trait includes viral genes that enable its integration into the host chromosome. However, the evolutionary path leading from a virus to an immense cluster of genes providing for nitrogen fixation is a mystery.

Beyond bacteria, human chromosomes have many retrotransposon elements, derived from certain viruses, whose influence on our biology is only beginning to be appreciated. These functions include regulation of gene expression, i.e. helping the cell decide which proteins to produce when and where. They also promote events that might cause indigenous segments of the host chromosomes to be deleted or otherwise rearranged, which can have an impact on the properties of these cells. More than humans, the chromosomes of many crop plants are loaded with these retrotransposons: they may account for up to 90% of the total genetic material of maize, making these chromosomes more viral than plant.

While we have said a few things about what viruses can do by getting their DNA into the chromosomes of their hosts, we have not said anything about how the viral DNA got there in the first place. The series of discoveries spread over 100 years, which eventually resulted in the present-day understanding of the roles of viruses in generating medically important functions of bacteria, stoutly fall under the category of basic science trying to understand the molecular basis of life and inheritance. These led to the birth of molecular genetics and subsequently genetic engineering, biotechnology, genomics and synthetic and systems biology.

In the second and final part, to be published on December 4, 2015, we’ll go back a century, to December 4, 1915.

Aswin Sai Narain Seshasayee runs a laboratory researching bacterial biology at the National Centre for Biological Sciences, Bengaluru. Beyond science, his interests are in classical art music and history.

Remembering Sambhu Nath De, the Medical Man for the Blue Death

The scientific genius of Sambhu Nath De was the source of discoveries in bacteriology that saved millions of lives around the world. A tribute on his centenary.

Scanning electron image of Vibrio cholerae. Credit: Wikimedia Commons

Ask someone what Black Death is and the prompt answer will be “the plague”. But, ask what Blue Death is and even some biologists might falter. The answer is cholera, historically known as Asiatic cholera. A highly infectious disease, cholera likely originated in India and caused at least three major epidemics in Bengal during the 19th century, before spreading across the world and killing millions. The terror of the scourge ensured that Oladevi (or Olabibi), the ‘anti-cholera goddess’, was devoutly worshiped by all Bengalis. John Snow’s 1855 discovery that the causative agent got transmitted via contaminated water revolutionised the field of epidemiology and public healthcare. A few decades later, Robert Koch, the iconic bacteriologist, conclusively identified the pathogenic bacteria: Vibrio cholerae.

Today, there has been a sea-change in our understanding of how the pathogen causes the disease. It is common knowledge that the actual mischief-maker is the cholera toxin (CTX), a complex of six proteins released by V. cholerae into the small intestine. When CTX enters the intestinal cells, it triggers a cascade of intracellular reactions. The final result is the opening of floodgates such that sodium, potassium, bicarbonate ions and water pour from these host cells into the intestinal lumen, causing intense diarrhoea (the faeces is typically rice-water-like in appearance) and a rapid loss of water and electrolytes from the body. Yet, Sambhu Nath De, the Indian scientist whose discoveries radically altered our understanding of the pathogenesis of cholera and also played a pivotal role in discovering CTX, is all but forgotten, even in his own country. On his birth centenary, it is worth honouring him by recalling his scientific genius.

The rice-water like appearance of the faeces of a cholera victim. Credit: Wikimedia Commons

Early years

De’s life exemplifies the ability of champions to overcome all obstacles. He was born in an impoverished family in a village close to the French colony of Chandannagar in Bengal in February 1915. A considerate uncle and a benevolent neighbour paid for his education till De won a scholarship to the Calcutta Medical College. He started a medical practice in 1939 but his heart was in the research laboratory. De’s mentor and father-in-law M.N. De was a renowned bacteriologist. Convinced that his jamai was destined to be a top-notch scientist, M.N. De recommended him to Sir Roy Cameron, a famous pathologist, and De joined the Cameron lab at the University College London as a PhD student in 1947. After an initial bout of struggle and depression, De’s research found its tracks and Cameron noted, “… he has regained confidence. He is doing excellent work.”

However, apart from his own thesis, De developed an intense interest in understanding the pathogenesis of cholera. By the time he returned to Calcutta in 1949 and was appointed the Chair of Pathology at the N.R.S Medical College, it was evident that research on V. cholerae would be his life’s mission. It was also a time when post-Partition Calcutta was overflowing with refugees and hundreds were being struck down by the Blue Plague. The N.R.S Hospital catered to most of the city’s cholera patients and provided De with the impetus to understand the pathogen, in a bid to ameliorate the suffering of his fellow-citizens.

Koch’s mistake

But unknown to all scientists in the 1950s, the major hurdle was a wrong scientific assumption. Several decades prior, Robert Koch – credited with discovering several pathogens – had concluded that V. cholerae primarily attacked the circulatory system of the patient, a rare case where Koch was off the mark. Yet, just as Ptolemy’s geocentric model had prevented most astronomers from thinking radically for more than a millennium, so influential had Koch’s ideas been on bacteriology that scientists had continued to study cholera by injecting the bacteria into the blood but never into the intestine.

The result was that, even after various bacterial preparations had been tested on different animals, the symptoms of cholera had never been replicated in the laboratory. And in absence of an animal model that could be studied in the lab, scientists were effectively groping in the dark.

De’s brilliance lay in breaking free of Koch’s idea. He hypothesised that the cholera bacillus’s main target was the cells lining the small intestine. To demonstrate this, he anaesthetised rabbits and introduced V. cholerae into the intestinal lumen. The rabbits did not suffer from diarrhoea but died a few days later. The autopsy, however, showed something remarkable. Usually, herbivorous rodents like rabbits have a large caecum – the pouch-like beginning of the large intestine that is directly connected to the small intestine and helps in digesting plant matter. In De’s own words, “… we found that the huge caecum of these rodents, which normally contain pasty semisolid material, was full of semiliquid faecal matter from which V. cholerae could be recovered…” De correctly concluded that the infection had initially caused fluid to flood the small intestine, but subsequently it had accumulated “in the caecal backwater’’.

The loop idea

In the following experiment, De tied two silk ligatures on either side of a four-inch segment of the small intestine, isolating this part from the rest of the gut. Then, he introduced the bacteria only into this segment. The next day’s autopsy heralded a scientific breakthrough: the isolated segment was swollen and distended with rice-water fluid, reminiscent of the faeces of cholera victims. The rest of the intestine – where no bacteria had reached – was in a collapsed state.

Sambhu Nath De. Credit: Wikimedia Commons

To quote De himself, “This represents cholera localised to a small segment of the intestine” and proved that the bacteria changes the permeability of the intestinal cells, resulting in an explosive secretion of fluids. The discovery, published in 1953 in an article titled ‘An experimental study of the mechanism of action of V. cholerae on the intestinal mucous membrane’, is considered a landmark publication. More importantly, it would pave the way for introduction of the oral rehydration solution (ORS), a simple, home-made therapy that has saved millions in India, Bangladesh and Africa.

Within the next few years, using the same ileal-loop technique, De demonstrated that several patients had been infected by strains of Escherichia coli, which induced similar intestinal secretions, another milestone. He received accolades for his work in the UK, much to the delight of his mentors.

Another seminal discovery was in the offing: the discovery of CTX. Today, it is recognised that a bacterial toxin can be either secreted by the pathogen (an exotoxin) or be an integral part of the bacterial cell itself (an endotoxin). The question was if the elusive CTX was an exotoxin or an endotoxin. No one knew but most believed it was the latter. Again, De’s experiments would cause a paradigm shift in scientific understanding. By 1957, De was labouring to identify the CTX so that it could be converted into a toxoid for use in vaccines. Since the medical college had no infrastructure for such a venture, he worked at the Bose Institute, Calcutta.

A premature close

Supremely passionate about science, he used to start experiments in the evenings after hospital duty and refused rest even on Sundays. The efforts bore fruit. De noticed that if V. cholerae was grown in a liquid medium and then the cells were removed, the cell-free filtrate could still induce cholera in the intestine. After having painstakingly repeated the experiments, De was convinced that CTX was not an endotoxin but an exotoxin that the bacteria released into the medium. When the CTX exotoxin reached the intestinal cells, it induced diarrhoea, the classic symptom of cholera. The findings were published in the journal Nature in 1959.

Unfortunately, although De was eager to identify the CTX molecule, the lack of modern equipment in India meant his work came to a screeching halt. As research surged ahead in the rest of the world, he felt disheartened at the lack of progress and recognition. He retired from the hospital, in 1973, and also from the laboratory. In 1978, however, he was invited by the Nobel Foundation to be a guest-speaker at a special symposium and received rich praise.

Science had been De’s only passion. He had never cultivated close relations with the establishment as such. Hence, as P. Balaram, one of India’s leading scientists and editor of the journal Current Science, noted in a special issue dedicated to ‘S.N. De and the cholera enterotoxin’ (1990), “… De died in 1985 unhonoured and unsung in India’s scientific circles. That De received no major award in India during his lifetime and that our academies did not see it fit to elect him to their Fellowship, must rank as one of the most glaring omissions of our time.” Indians lament that scientists such as J.C. Bose, Meghnad Saha and S.N. Bose never received a Nobel Prize. But they have at least won the adulation of the common Indian. In contrast – and what is perhaps more tragic – is that De’s heroic tale of intellectual brilliance and perseverance has remained unknown to the layperson. Yet it is certainly one of the most inspirational in the annals of modern science and Indian researchers would do well to emulate him.