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Biotechnology and Society---Part XIV

Note: This is a eulogy and not a trivial (let alone ribald) topic. Bacteria do vital service to mankind, of course at the command and direction of the scientists. This article examines the lighter and useful side of bacterial life. In this article we are using the word ‘sex’ to denote transfer of genetic material in the generic sense.

Since the beginning of civilisation, it has been the custom of human beings to subjugate and enslave other human beings and exploit them to do their bidding, by force, if necessary. History records that the Greeks were taken slaves by Romans to serve in their households, although the Greeks were more educated than the Romans. In later times, we experienced the enslavement of the people from the African continent by various European and American nations as well as the colonisation of African and Asian continents. Only in recent times such practices have stopped.

The domestication of wild animals to serve mankind was known from very early times. Horses, cows, bulls, sheep, goats and other animals were put to various duties around the house and the farm. However, the taming of the microorganisms in the service of mankind is a much more recent phenomenon. Bacteria and yeast have been used by man, without even realising they are there, in the baking of bread, brewing of beer, fermenting the wine and making the yogurt, from very early times. The 20th century witnessed the real exploitation of selected fungi and bacteria to make antibiotics to combat diseases caused by harmful bacteria. Science started practicing the maxim, “divide et impera” (divide and conquer) in the microbial world.

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Since the advent of the modern era of biotechnology in the late 20th century, bacteria have been enslaved for the production of a variety of chemicals and drugs. We noted in the previous article how bacteria are manipulated to make life-saving pharmaceuticals through recombinant DNA techniques. The method of recombinant DNA is designed to exploit the bacteria. There is no SPCB (Society for the Prevention of Cruelty to Bacteria) to protect the bacteria while there are groups like PET (People for Ethical Treatment) for animals. Let us now examine how the bacteria live, entertain themselves and die (not of their own volition).

Biography of bacteria: Bacteria are much closer to immortality than animals, including humans. Cell division generates identical copies of a bacterial cell. This is known as asexual reproduction. Bacteria can be killed, but death, as we know it, is alien to them. They live until they divide. Then, as two cells, they beget generation after generation forever. Each bacterium vanishes into its offspring and gets to live again. Immortality is in their “blood”. One bacterium becomes two in about 20 minutes. The geology of our planet is due to the work of bacteria. The mineral deposits have been shaped by bacterial metabolism over millions of years. If all bacteria died, there would be no other life. If we eliminated all bacteria from our bodies, our bodies would not be able to perform vital functions.

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When life was created, bacteria were the first beings. They grew at phenomenal rates, utilising ubiquitous organic compounds. They used available sugars, available light to produce energy and even water (by extracting hydrogen atoms from water). Bacteria keep on growing and dividing until all food is gone. Even then they can fold up and remain forever as spores. They can survive in the harshest of environments. They have spent three-and-a-half billion years in our planet, practising life and chemical warfare. They outnumber humans and some possess WMD (Weapons of Mass Destruction). Humans thought that antibiotics would end infectious diseases but the bacteria were smarter and invented sex. Yes, sex was invented by the lowly creature, bacterium.

Do bacteria indulge in sex?: Bacteria don’t have sex in the traditional sense of the term. They multiply asexually. However, they can reproduce sexually using a technique known as plasmid (rings of DNA) migration. They wander around, bump into each other and “talk” to each other as to whether they want each other’s genetic material. With mutual consent plasmid(s) are exchanged through the cell membrane. Usually, this is done for survival to fight antibiotics and other toxins that are detrimental to them. Vegetative bacteria unite by a conjugation bridge through which all or part of a male genome migrates into the female cell. The gametic cells then separate. The ex-conjugant male goes on to multiply unaltered, surviving by virtue of its remaining DNA. The ex-conjugant female generates a mixed clone, some its own original copy (unaltered) and others modified slightly by virtue of the conjugal event, but still all are immortal.

The distinction between “male” and “female” bacteria arises solely from whether they donate or receive the DNA. The bacteria can belong to different species while engaging in sex (a sort of inter-caste marriage). It is basically “sex-on-the-run” for bacteria. This is because they continuously travel at about 50 kmph. At this rate of travel, conjugation is a “hit or miss” situation. Every time when a “female” mates with a male, she turns into a male. In bacteria, “maleness” is thus an infective venereal disease, so to speak.

Paramecium (a primitive protozoan) uses bacteria for food. They replicate just like bacteria. However, they are not as fecund as bacteria. Each succeeding generation of isolated paramecium cells grows weaker and weaker until they finally die, i.e., if they remain celibate. But sex saves them from death. Following a conjugal event they keep on dividing (what a rejuvenation following sex!). Sex appears to be life’s ambrosia, much more than a reward for paramecium.

Genetic engineering and recombinant DNA technology are primarily techniques to let bacteria have sex at the command of the scientist. This procedure is similar to artificial insemination practised in animal husbandry to produce desired traits. The foreign gene is introduced in a plasmid and the bacterium is forced to take up the plasmid (or “have sex” with the adventitious plasmid) and produce the product intended, in the interest of service to mankind. They comply although it is involuntary sex. Mankind enslaves even the bacteria. Is it justified? The irony of it all is that at the end of the service by bacteria, they are mercilessly killed during isolation of the desired product and a new generation of bacteria is commanded to take over the function of their predecessors. That is the business of biotechnology!

Sex and death: While bacteria are immortal, it is a mystery why evolution guided life upwards into multi-cellular beings with reproductive capability through sex. Animals that evolved from bacteria have two genders (called “sexes” in some societies) and produce offspring through mating, age, and finally die. Before sex came on the scene, offspring were cloned without the help of a partner. Underground runners of plants created multiple clones. Potatoes clone through budding. Bulbs (like daffodils, tulips and onions) divide underground. Cacti let pieces of themselves fall to the ground and reproduce. Flatworms, when cut in two, grow a new head and a new tail on the two halves.

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So, why did sex develop on earth? Sexually reproducing species are still a mystery and so is death which appears to be a byproduct of sex. It is not inappropriate to say that “death was the first sexually transmitted disease”. The ageing and dying were passed on to the offspring. The evolutionary advantages of muticelluar beings may have led to sex as a vital means for reproduction through mixing gene pools. It is hypothesized that asexual reproduction may not have gotten around to delivering humans. Sex provided mixing gene pools and thus a protection against environmental stress. The question that arises is: Do you want immortality and enjoy life at the top of the evolutionary pyramid as well? We, as human beings, do not have that option right now. Perhaps, in the distant future, we may have both!