Replicide leapt free of the bounds of evolution. As a self-replicating but non-living entity, it could enter any living, or for that matter recently dead, body where it would begin consuming cellular tissues in which it resided, all the while building ever more copies of itself. Replicide was a product of evolution, but it obeyed none of evolutions’ constraints. No life form on Kalekto had coevolved with Replicide and no life form had the ability to resist its effects. Replicide did not follow any productive path to spare its host, as a parasite might do, and would consume and kill any organism it inhabited. It did not die when the organism did, but could sit there in the remains waiting to be consumed. It spread rapidly through the food chain to every species in every corner of Kalekto.
Healthy individuals were able to live with a Replicide infestation for some considerable time. At first, when the concentration of Replicide in their body was very low, the rate of reproduction of Replicide was restrained by the normal healthy functions of the body. Replicide was dependent on its ability to remove amino acids from nearby proteins. While it could do this reasonably well, it did not have a good ability to hold onto the amino acids that it freed. They could be washed away and could just as well become substrates for the normal, constructive synthesis of new proteins, including the replacement of proteins already destroyed by Replicide. Eventually, inevitably, this balance shifted and the concentration of Replicide increased, perhaps after eating flesh infested with Replicide, when weakened by a lack of food, or during an illness that slowed recuperative powers. Once the tissue levels of Replicide passed through a lethal threshold, it moved quickly, digesting tissues ever more rapidly, chewing up muscles and making ever more copies of itself. The process continued even after death, converting the body into an empty sack in a puddle of lipid slime. Even then, Replicide survived. Proteins can exist for hundreds of years.
YuLon called an early morning conference in the Farside module so that CamBi could present her findings on the Kalekto disease. Even as she began, the security alarm in the Huc habitat sounded. YuLon held up her hand to stop the meeting and ran quickly down the hallway to determine its cause. ObLaDas rarely ran, so it was something to see. She returned in less than a minute, flushed with concern. Two Huc corpses, wasted and partially decomposed, had been found in the refuse area of their habitat. She told CamBi to come with her. CamBi felt frustrated and puzzled as they walked to the security monitors to see the bodies. She did not need another distraction. The appearance of the bodies shocked her into an even less pleasant reality. The Huc corpses were very similar to that of twenty-six, she had to believe that they been killed by the same disease, Replicide. CamBi left immediately and rushed back through the hall. She grabbed Di DonSi, and together they entered the transit shuttle. She shut the doors, not waiting to see if anyone else was coming.
“So,” she asked Di DonSi, “how many connections are there between the habitats?”
“None,” he answered, “They are completely sealed off. Not even light gets out of a habitat. You know that.”
“I know they are sealed.” She answered more sharply than she intended, “but there are pipes. Food and water go in, crap and junk come out. What about those? We have got to think. How were the Hucs infected?”
“How do you know it is the same disease, how can you be sure? We need to run some tests, don’t we?” Di DonSi answered, angrily, as the shuttle wavered along its cables.
CamBi waved her hands quickly, dismissing this line of discussion. “There is no doubt, Dio. The Hucs are one of the oldest species on board. They have been here for three thousand years. Twenty-five days after the Kalektos arrive, they start to melt. What else can it be? What about waste products? They would be contaminated. Could it have gotten out that way?”
Di DonSi slumped into a corner to hold on as the shuttle became less and less weighted. “Well, it could get out that way, of course, but that would be the end of it. All organic waste is broken down to the unit molecular level before it is passed on for recycling, but not even that is happening. The two little habitats that are operating in the Farside are so small that we have been stocking up their waste material. Recycling will not begin until we get enough to work on. Only metals are being recovered at this point, and that is mostly from scrap construction material,” he said as he looked closely at CamBi. She was holding onto the retaining rail with both mits firmly clenched. He was hardly being helpful, as the car ran weightless past the hub.
“Air, water, food, meds, what else got in there? How could that be the cause?” CamBi asked, she was talking to herself now, but not answering that it would be all her fault if it had. “Dio, we need to check everything. You can see that can’t you.”
Of course he could. Diseases rarely crossed from one species to another, even on the same planet. Crossing to an alien species was incomprehensible and ominous. If it could kill the Hucs, no one was safe? Di DonSi began to feel uncomfortably confined within the suddenly small Outward Voyager. He turned inward to think through the tests he would start and what else might be done. The humans could help, he decided. There were three in his work party. They would be perfect for this type of thing. They need not be told that they were in danger.
CamBi was making her own plans. She would get YuLon to send in more medical units, new ones, to get samples from the Huc corpses, and another one to sample the air, food, water, whatever the Hucs might have consumed. She would look into her own stores for any trace of Replicide. The shuttle eased to a stop, the doors finally opened, she walked into her anti-mod laboratory without another word. Di DonSi was away to get on with his grim and urgent duty.
CamBi worked through the day and well into the night. Exhausted from tension as much as the long hours, she finished loading the last of the tissue samples from the Huc habitat. The dead, the living, and everything else she could think of, were all set running in the auto analyzers. Finished at last, she fell asleep in the corner of the lab to the droning hum of pumps and clicking valves.
It seemed only minutes later that CamBi was woken by YuLon’s urgent message. Without a greeting, YuLon began telling her that several LabislassLees were complaining of feeling pains and cramps. “Could they be infected too?” YuLon asked, hardly expecting an answer to her own question.
CamBi did not give her one, as she asked instead to have a full sampling of the LabislassLee habitat. “And don’t let anyone or anything enter or leave the Farside Arm,” she added. Even though she had slept for half the night, CamBi felt as bad as she ever had, but instead of lying back on her pleasantly warm mat or freshening her slime, she went straight into the dimly lit lab to look at the early test results. The instrument lights blinked as they worked away, the samples were not half finished, but a great deal of information was already available. The first samples and the fastest test would identify Replicide in the tissue of the Huc corpses, if it were there. She was surprised. The initial scans were not positive for Replicide, but gave a weak, inconclusive signal instead. The more detailed test results that she needed to learn what that meant would not start coming in for another hour. She sat down to pick at the leftovers from last night’s meal, and called YuLon about the LabislassLees.
“Nothing new,” YuLon answered, “at least none of them have died yet. We started taking samples of everything, but it got them in a panic. Those clever little bugs had tapped into the ship’s communications and had been listening to the whole story. They are desperate to get out of the Farside arm, but nothing and no one will be allowed into the rest of the ship. MaxNi9 has decided to isolate the arm. He will have a horde of humans cutting all the pipes, ducts, and conduits, whatever.”
And I will be as trapped as they are, CamBi said to herself, and I had better figure out what is going on and be quick about it. She found out soon enough, and was not happy about what she learned. The Huc tissues were loaded with a protein, not Replicide, but a close relative. It was a protein, with some different amino acids, but with almost the same activity. She walk
ed slowly over to the sample storage vault, not really believing what she knew to be true. She took out a tissue sample from one of the Huc corpse, warmed it up to body temperature, and watched the son-of-Replicide ate away at the tissue, sinking it into a slimy puddle.
Her mind was a muddle of unanswered questions. How had Replicide spread? Why was it changed? Could this be my fault? She called Di DonSi to see if he had found anything.
“No, not so far.” He would form a work crew, humans not bots, to search the exteriors of the Huc and LabislassLee habitats for leaks and they would work back along the connecting tubes outside the modules until they found something. He would let her know.
CamBi picked up her puddle. She felt somehow connected to this muck. It was real to her now, and she took some comfort from being able to see it as something real, however disturbing it may be. The destroyed tissue was filled with the Replicide lookalike. It was almost the only protein left, which made isolation and purification easier. Maybe, if she understood more of this compound, she would be able to understand what was happening. The size, activity, and function of the protein were all close to the Kalekto version of Replicide, but a little different. Her big clue came from the amino acid composition. The new Replicide was composed entirely of the simplest, most common amino acids.
Note: Amino Acid Commonality
The communicated knowledge of the galaxy had documented life on many different planets. The most fundamental of these discoveries was that all life forms, no matter where they existed, had some basic features in common. Every life form was made up of the same molecular families. All living organisms required water and were carbon based, this was no surprise, but it was found that they all were constructed using self-replicating cell-like structures having common features. Small units combine to make large, complicated ones, molecules, biochemicals, cells, and bodies. It was a common theme in all levels of galactic life. Genetic information is carried by strings of nucleic acids or something close to it, self-associating lipids form cell membranes and compartments, sugars or carbohydrates store energy, while many different proteins facilitate chemical reactions, form structural units, and perform other duties needed to sustain life.
The detailed structures of the molecules within these families vary from planet to planet, but the same basic molecular types are always present. This was no coincidence, or so the Primaforms had theorized. They had been the first to work it out. Apparently, the list of requirements needed to contribute to a living organism was so lengthily and so restrictive, that only those few molecular families possessed the array of properties necessary to meet them. They must be easy to form under the prevailing environmental conditions in order to be present in the primordial ooze, stable enough to survive in that bubbling stew, and most importantly, have the requisite chemical properties to be able to combine to construct larger entities that can perform some function useful to a living, self-replicating organism. It is why a few preferences can narrow your list of a thousand cars to one or two models.
Enzymes and receptor molecules are proteins made of alpha amino acid chains. The exact same amino acids are found in every life form, but there were always a few that were unique. Proteins are long chains made up of the twenty or more different amino acids. Each protein has a unique sequence of amino acids and that sequence causes the protein to fold into a specific shape. Shape gives these globular molecules their function, in the same way that a baseball glove can hold a ball because of its pocket-like shape. The key feature of alpha amino acids is that they have the same three-atom N-C-CO unit, but may have different sets of atoms attached to the central carbon. These groups of atoms appear as a series of side chains set close together along the length of the peptide and the interactions between these side chain atoms determine how the protein will fold and what function it may perform.
|
NH
CH-Side chain
C=O
NH
CH-Side chain
C=O
|
Most of the twenty-five amino acids in Kalekto proteins were the same those found in other species. In fact, seventeen occur in the ObLaDas species, but Kalekto life had eight others that were different. Alieｻ proeiｻ are like a eｻence made usiｻg a few leer from iffereｻ alphabe. Why not? The simplest would be the easiest to form and probably the most abundant, while the more complex could derive a desirable property from any one of several related but different structures. The commonality of amino acids is the practical feature that enabled the ObLaDas to maintain life on the Outward Voyager. Having a pool of the amino acids common to all species allowed the ObLaDas to quickly complete the specialized mix needed to produce foodstuffs required to feed to feed each alien species. And now it has opened the door to their potential destruction.
-MDK
CamBi headed the ObLaDas’ facility that prepared foods for every species on board the Voyager. These foods were not always a gourmet delight. The Voyager could not simulate a steak, in spite of having the right proteins and fats, but it could make a passable paté. The ObLaDas collected a variety of foods whenever an alien was captured, usually enough to feed them for about three months, and to identify and copy the molecular structures that composed their diet. They had those three months to succeed or the aliens would starve, which is why it was essential to know that the alien they encountered would be biochemically similar to the ObLaDas. It would not be possible for the ObLaDas to invent and implement a completely new suite of technologies within that fixed time limit.
CamBi knew that all of the Kalekto foodstuffs had been sterilized and decontaminated before being brought into her laboratory, but those procedures would not destroy molecular structures and so they did not destroy Replicide. The Replicide in the Kalektian foods was treated as just another nutritious protein.
The Voyager used genetically engineered bacteria-like organisms to make bulk quantities of the needed Kalekto proteins. They fed the bacteria a mix of the appropriate nutrients, including the required amino acids, and the organisms converted them to edible proteins. The ObLaDas took advantage of the fact that their alien life forms had many of the same amino acids in common, and used a pool of the common amino acids for all production so that they only needed to spike in the unique amino acids required for each alien species. Somehow, while CamBi was running trial batches of Kalekto proteins, the tank of common amino acids had become infected with Replicide. This was bad practice, no question, but it should have been the end of the story. What harm could a few protein molecules do? The common amino acid pool did not even contain all of the different amino acids needed for Replicide to copy itself.
Replicide could replicate itself, but its ability to select the correct amino acid to put in each position on its long chain was not particularly good. As a consequence, a Replicide molecule would frequently make versions that were a bit different from the original, one with a variant amino acid here and there. Just what it needed! In a living animal, Replicide reproduction was a slow process because free amino acids were not always present in a useful concentration, but in the tank full of common amino acids, Replicide was swimming in a nutritious soup and could work at a prodigious rate. It was able to produce innumerable imperfect versions of itself by inserting available amino acids in place of those that were missing. Most of these new Replicide variants did not work, or did not work very well, but applying evolutionary terms to the molecular scale, many Replicide generations were produced per minute and with a particularly high mutation rate. Whenever a slightly more efficient variant was produced, its more rapid replication rate quickly made it the dominant population in the media and the springboard to even more effective forms, forms that needed only common amino acids. The amino acids that were present in every species alive on the Outward Voyager. It did not take long for the Replicide that was growing in the common amino acid mix to show up in all the food that was produced in the Farside anti-mod.
CamBi went o
ver to the central communication station to report her findings - the Huc Replicide was present in the common amino acid pool. She was overcome by a strange calm and just sat at the console for a while. There was no hurry in her anymore. Replicide might be spreading its way throughout the Outward Voyager and there was be nothing that she could do about it. She could be walking around in a ghost ship, if she were walking at all. Numbed by this realization she continued as if in a dream, barely conscious of her actions.
It was all her fault of course. She had tested the common amino acid mix. Replicide was there. The vat was full of it. Somehow, Replicide had adapted to life in that unnatural soup. The Son-of-Replicide was in the food she had sent to the Hucs and LabislassLees. Every species on the ship had their food made from a common mix of amino acids, even the ObLaDas. So far, the Farside lab had only made food for the three species that were living on that side of the ship. Was that so? She should make sure that none of the Farside common mix had been shipped the other way. They had rules to keep things isolated so that had probably not happened yet. Nothing seemed to make much difference as she sat there with her thoughts.
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