<p>Has the earth had extraterrestrial visitors in the past? Are they still around and more importantly, will they continue to visit us in the future?</p>.<p>These are questions that have been plaguing humanity for several decades now. However, there are several twists and turns to the tale. When one imagines an extra-terrestrial (ET) visitor, the image that springs to mind is that of a green creature with large haunting eyes and multiple limbs.</p>.<p>Consciously or subconsciously, we always imagine the ET to be ‘human-like’ or humanoid. Yet, why should an ET don a human form? Could it be a simpler organism, smaller, invisible to the naked eye? Bacteria or viruses perhaps?</p>.<p>It would be logical to assume that the extra-terrestrials are not multicellular organisms but unicellular and relatively less complex organisms. After all, this planet harbours only about 5,400 species of mammals while the number of species of unicellular organisms has been estimated to be in thousands.</p>.<p>There are about one sextillion bacteria for each human being (that is, 1 followed by 21 zeros). Going by the probability of chance alone, it is likely that a bacterial species would have reached earth from outer space rather than the humanoid species alluded to earlier. It is also likely that bacteria would survive the ardours of space travel being relatively less complex and unicellular organisms. </p>.<p>But the burning question is, are there bacteria in outer space. In 2017, the Russian cosmonaut, Anton Shkaplerov performed spacewalks and collected samples from the exterior of the International Space Station. These samples were collected using cotton swabs and were sent to earth for analysis. The analysis showed that the swabs contained bacteria which were absent during the launch of the module. This suggested that the organisms had come from outer space and settled on the exterior of the International Space Station.</p>.<p>Would this suggest that outer space has a bacterial population and some of them have already visited us in the past? Purists would argue that it is quite impossible for organisms to survive in the harsh environment of outer space. The counter-argument is that bacteria are extremely hardy and incredibly versatile. In recent times, scientists have isolated a bacterium in Antarctica which can survive solely off of chemicals in the air. They require just hydrogen, carbon monoxide and carbon dioxide to survive.</p>.<p>This would mean that it is very likely that there are organisms in outer space which can make do with very little. The documentation of these “extremophiles” indicates that extra-terrestrial life could exist in much wilder circumstances than previously thought.</p>.<p>Do these microbes have a message for us? Bacteria contain DNA (Deoxyribonucleic Acid) also called the thread of life. DNA contains four nucleotides which occur in specific sequences. Scientists believe that the sequence of nucleotides could be conveying a message. It is possible that there are patterns in the given sequence of DNA, an ‘Encyclopaedia Galactica’ which could be conveying a message which we cannot decrypt.</p>.<p>Understandably, the bacteria which have to make the arduous journey through space would have had to adapt to space travel. As an adaptive mechanism, the bacterial volume shrinks (up to 73% in some cases) and the cell membranes become thicker (up to 25% in some cases).</p>.<p>Several other changes also occur which give the bacteria a survival advantage. These survival strategies would entail changes in the genetic composition of the bacteria.</p>.<p>If a bacterium has a survival gene ‘X’, it can pass on this survival gene to several hundred other bacteria enabling all of them to survive under difficult circumstances. So, in effect, you could have one bacterium which adapts to an environment and this would be passed on to several million other bacteria. What survival advantages could the ‘Bacteria Galactica’ have given our own earthly bacteria? Was perhaps, antibiotic resistance a gift for ‘Bacteria Earthica’ from ‘Bacteria Galactica’. Fleming discovered penicillin in 1928.</p>.<p class="CrossHead"><strong>Therapeutic tool</strong></p>.<p>In 1940, several years before the introduction of penicillin as a therapeutic agent, a bacterial penicillinase was identified by two members of the penicillin discovery team. Had our own earth-based bacteria already learnt about antibiotics and their effects well before humans began to use antibiotics as a therapeutic tool? And were their teachers ET which were tiny microorganisms and not ‘humanoids’ as we would like to believe?</p>.<p>These facts throw up some very interesting possibilities. First, it is very likely that ET organisms have already visited us in the past and will do so in the future. With our limited knowledge, it is difficult to imagine that the DNA sequences in the bacterial genome could be conveying a message.</p>.<p>However, it must be remembered that there is a likelihood that these DNA sequences are encrypted messages for us from the other parts of the universe.</p>.<p>Finally, it would be most interesting to speculate if the original culprit who taught other bacteria how antibiotic resistance is to be acquired, originated from outer space. If that is true, rest assured that there are mirthful microbes sitting out there watching humans try to solve the menace of antibiotic resistance.</p>.<p><em>(The writer is Senior Consultant, Surgical Pathology and Molecular Diagnostics, Neuberg Anand Reference Laboratory, Bengaluru)</em></p>
<p>Has the earth had extraterrestrial visitors in the past? Are they still around and more importantly, will they continue to visit us in the future?</p>.<p>These are questions that have been plaguing humanity for several decades now. However, there are several twists and turns to the tale. When one imagines an extra-terrestrial (ET) visitor, the image that springs to mind is that of a green creature with large haunting eyes and multiple limbs.</p>.<p>Consciously or subconsciously, we always imagine the ET to be ‘human-like’ or humanoid. Yet, why should an ET don a human form? Could it be a simpler organism, smaller, invisible to the naked eye? Bacteria or viruses perhaps?</p>.<p>It would be logical to assume that the extra-terrestrials are not multicellular organisms but unicellular and relatively less complex organisms. After all, this planet harbours only about 5,400 species of mammals while the number of species of unicellular organisms has been estimated to be in thousands.</p>.<p>There are about one sextillion bacteria for each human being (that is, 1 followed by 21 zeros). Going by the probability of chance alone, it is likely that a bacterial species would have reached earth from outer space rather than the humanoid species alluded to earlier. It is also likely that bacteria would survive the ardours of space travel being relatively less complex and unicellular organisms. </p>.<p>But the burning question is, are there bacteria in outer space. In 2017, the Russian cosmonaut, Anton Shkaplerov performed spacewalks and collected samples from the exterior of the International Space Station. These samples were collected using cotton swabs and were sent to earth for analysis. The analysis showed that the swabs contained bacteria which were absent during the launch of the module. This suggested that the organisms had come from outer space and settled on the exterior of the International Space Station.</p>.<p>Would this suggest that outer space has a bacterial population and some of them have already visited us in the past? Purists would argue that it is quite impossible for organisms to survive in the harsh environment of outer space. The counter-argument is that bacteria are extremely hardy and incredibly versatile. In recent times, scientists have isolated a bacterium in Antarctica which can survive solely off of chemicals in the air. They require just hydrogen, carbon monoxide and carbon dioxide to survive.</p>.<p>This would mean that it is very likely that there are organisms in outer space which can make do with very little. The documentation of these “extremophiles” indicates that extra-terrestrial life could exist in much wilder circumstances than previously thought.</p>.<p>Do these microbes have a message for us? Bacteria contain DNA (Deoxyribonucleic Acid) also called the thread of life. DNA contains four nucleotides which occur in specific sequences. Scientists believe that the sequence of nucleotides could be conveying a message. It is possible that there are patterns in the given sequence of DNA, an ‘Encyclopaedia Galactica’ which could be conveying a message which we cannot decrypt.</p>.<p>Understandably, the bacteria which have to make the arduous journey through space would have had to adapt to space travel. As an adaptive mechanism, the bacterial volume shrinks (up to 73% in some cases) and the cell membranes become thicker (up to 25% in some cases).</p>.<p>Several other changes also occur which give the bacteria a survival advantage. These survival strategies would entail changes in the genetic composition of the bacteria.</p>.<p>If a bacterium has a survival gene ‘X’, it can pass on this survival gene to several hundred other bacteria enabling all of them to survive under difficult circumstances. So, in effect, you could have one bacterium which adapts to an environment and this would be passed on to several million other bacteria. What survival advantages could the ‘Bacteria Galactica’ have given our own earthly bacteria? Was perhaps, antibiotic resistance a gift for ‘Bacteria Earthica’ from ‘Bacteria Galactica’. Fleming discovered penicillin in 1928.</p>.<p class="CrossHead"><strong>Therapeutic tool</strong></p>.<p>In 1940, several years before the introduction of penicillin as a therapeutic agent, a bacterial penicillinase was identified by two members of the penicillin discovery team. Had our own earth-based bacteria already learnt about antibiotics and their effects well before humans began to use antibiotics as a therapeutic tool? And were their teachers ET which were tiny microorganisms and not ‘humanoids’ as we would like to believe?</p>.<p>These facts throw up some very interesting possibilities. First, it is very likely that ET organisms have already visited us in the past and will do so in the future. With our limited knowledge, it is difficult to imagine that the DNA sequences in the bacterial genome could be conveying a message.</p>.<p>However, it must be remembered that there is a likelihood that these DNA sequences are encrypted messages for us from the other parts of the universe.</p>.<p>Finally, it would be most interesting to speculate if the original culprit who taught other bacteria how antibiotic resistance is to be acquired, originated from outer space. If that is true, rest assured that there are mirthful microbes sitting out there watching humans try to solve the menace of antibiotic resistance.</p>.<p><em>(The writer is Senior Consultant, Surgical Pathology and Molecular Diagnostics, Neuberg Anand Reference Laboratory, Bengaluru)</em></p>