chiaravi@silver.bacs.indiana.edu (Lucius Chiaraviglio) (09/12/89)
[Note: I don't get sci.astro] In article <375@msdrl.UUCP> elliston@msdrl.UUCP (Keith Elliston) writes: >In article <2043@ibmpa.UUCP>, szabonj@ibmpa.UUCP (nick szabo) writes: [Identity of ">> >" poster in this section of message unknown] >I just wanted to add a few comments from a biologist's point of view.... Following are some more comments, from another biologist's point of view. >> >A number of experts believe that despite the harsh >> >environment of outer space, a large colony of earth >> >microorganisms will survive the journey to Jupiter in the >> >interior of the spacecraft. > >Many microorganisms, especially fungi, have a physiological mechanism for >dealing with temporary nutrient starvation and generally inhospitable environs. >This state is called a spore. Fungal and bacterial spores can survive some of >themost extreme environmental states.... for example, some fungal spores can >survive autoclaving (121 degrees C, 15-18 psi) for prolonged periods. I can >easily imagine such spores surviving a journey through space. And these organisms are also quite good at surviving irradiation. It has been said before by some of the posters whom I am following up (and in other messages), but it should be restated at the beginning of the message: bacterial spores survived for several years on a supposedly sterile Surveyor lander on the moon. >Also, it should be noted that there do exist bacteria that grow only using >Hydrogen sulfide for energy, Minor quibble: they also need something to react the hydrogen sulfide with, such as Fe/Fe(2+)/FeS (reactions with these are exergonic) or carbon dioxide (additional energy, such as light, is required to drive this reaction). > and other species that live at high temps on >the steam vents at the bottom of the oceans. If there is an environment that >can be found on earth, there are organisms that can be found growing there. Minor quibble: I haven't heard of anything found growing in glowing lava lakes. :-) . . . yet. 8-) >> >Although conditions on Jupiter are very different from >> >earth, the planet's atmosphere includes clouds of liquid water at >> >temperatures at which earth microbes could survive and grow. >> >> What about necessary proteins, minerals, vitamins, etc.? What about >> the updrafts/downdrafts and temperature extremes? Have any experiments >> performed or was this just a research paper? > >This is interesting..... First, I think that it is possible for bacteria to >adapt to almost any temperature condition... and if a reasonable temperature >range exists, then we can expect microbes (bacteria and fungi) to survive, >and possibley prosper. The question of nutrients.... As long as the 4 majors >are there...Carbon, Nitrogen, Oxygen and Hydrogen, I think life could adapt. >Since I am not an astronomer (or astrophysicist), I am not sure if these >elements are available in the jovian atmosphere... but if there are, well, >Life could persist. I don't think it would be easy -- in fact it would be very difficult if not impossible -- for known terrestrial life to adapt to the absence of several other elements. While it is true that carbon, nitrogen, oxygen, and hydrogen are the most abundant elements in terrestrial life, phosphorus and sulfur aren't exactly minor elements. Phosphorus is an essential component of nucleic acids and phosphorylated compounds (including but not limited to free nucleotide polyphosphates), and sulfur is a constituent of two of the 20 "standard" amino acids as well as several other vital compounds. Salts must also be present, and monovalent element salts constitute a significant fraction of the weight of terrestrial living matter, while divalent metal salts are present in smaller amounts but still vital to some very fundamental processes of terrestrial life. Note that these elements do not need to be present as familiar compounds of life (proteins, vitamins, etc.) for some organisms to be able to use them -- many organisms can make anything they need as long as they are given the elements to make them with along with an energy source (possibly present in the form in which the elements are stored). It has been a long time since I read an article about the composition of the Jovian atmosphere, and much (if not all) of what I remember is pre-Pioneer and all of it is certainly pre-Voyager. However, I do remember that carbon, nitrogen, oxygen, hydrogen, and sulfur are present in the Jovian atmosphere. I have no data about the amounts of other elements in the Jovian atmosphere, although it does not seem impossible that some or all of these might be present in amounts too small to detect by Earth-based spectroscopy as dust in the lower atmosphere, which could be hydrated to salt solution droplets in the upper atmosphere (anyone have any better information on this?). I should point out that some terrestrial microbes are capable of growing by using extremely low concentrations of the vital elements, and that they are capable of using these elements in many forms. As one who has found mold growing in highly purified water, I can testify to this; from a professor of microbiology at Indiana University I learned that mold can grow even in water that has been purified to homogeneity, because as soon as it comes in contact with the air it is no longer absolutely pure due to the presence of organic compound vapors in the air which dissolve in it, and also because very small amounts of various compounds leach out of the plastic or glass of the container, and the mold (and also some bacteria) are capable of using these various compounds. >> >Even if the microbes could not survive on their own, the Sagan >> >paper suggests they could find a supportive environment inside >> >native organisms on the planet. > >This assumes that life is present on the planet... Not argueable at this >point.. It would be nice to find this out before we introduce life there, even though the probability of its long-term survival there seems low (because I don't think we have enough data to say for certain that this probability is zero). >> In article <1989Aug31.131156.27666@jarvis.csri.toronto.edu> >> wayne@csri.toronto.edu (Wayne Hayes) writes: >> >irresponsible mistake, to launch the atmospheric probe. In the remote >> >possibility that Jupiter's atmosphere harbors indigenous life, we may >> >pollute the atmosphere with Earth's life and never know for sure whether >> >the life we later discover is in fact indigenous. >> >> It will be very easy to discriminate life native to Jupiter or other >> planets from Earth life, just as it is easy to distinguish bats from >> birds, or prokaryotes from eukaryotes. Earth life consists of only >> a minscule fraction of possible DNA combinations (something like >> 10^14/4^10,000=1/10^5,986). Even if we go wild with the Drake equation, >> and assume DNA is the only possible structure for life, there will be >> no repititions, or even anything close, to Earth life anywhere else in >> our galaxy. > >It would be a good idea to explain your numbers... I assume that 4^10,000 >has something to do with the number of base pairs of DNA in something... >but I really can't figure out what this means... I think that what Nick Szabo (if I haven't mixed up my poster identities by this point :-P) is trying to say is that the information of content of DNA is so large that the probability of independantly-evolved life having sequences significantly homologous (that is, beyond the background homology found between any two random sequences) is astronomically small. [A considerable amount in which I agree with Keith's comments deleted] >Now... to introduce another thought.... [Some more that I don't agree with deleted to reduce the amount of material inappropriate for sci.space/sci.astro] >Life does not seem to require DNA or RNA or Protein... in myu opinion. It only >requires some organized way to form structures that can catalyzed chemical >reactions, and a way to store and modify the information needed to make there >structures. This sounds reasonable, although none of the compounds on the probe other than microbial spores are likely to be able to do this. > If we send ina ready made system... RNA or DNA and Proteins, >perhaps they can start evolution all over again, in a manner that can survive >in the vastly different environs found on other planets. These molecules are reasonably stable for the purposes of the terrestrial life made up of them, but are really fragile out by themselves, and are not capable of starting or sustaining life by themselves, even in an environment like the legendary and probably fictitious "prebiotic soup" of the oceans of ancient earth. In other words, it is valid to worry about sending whole microbes to Jupiter, but you don't need to worry about the non-microbial components of finger grease. | Lucius Chiaraviglio | Internet: chiaravi@silver.bacs.indiana.edu BITNET: chiaravi@IUBACS.BITNET (IUBACS hoses From: fields; INCLUDE RET ADDR) Internet-gatewayed BITNET: chiaravi%IUBACS.BITNET@vm.cc.purdue.edu Alt Internet-gatewayed BITNET: chiaravi%IUBACS.BITNET@cunyvm.cuny.edu