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Saturday, February 5, 2011

membranes of the microbial cockatrice

A cockatrice was a  wild dish served  at medieval  banquets.  It was a cooked dish of a rooster fused to a suckling pig.   Archaebacteria, as suggested by some microbiologists, are a microbial version of the cockatrice, since they appear to have genomes composed of both prokaryotes and eukaryotes.  
However, what is even more interesting is the different kinds of lipids and structures which make up the outer membrane and walls of the archaebacteria.  Some archaebacteria have monolayers rather than bilayers in their membranes.  They also have different lipids suggesting that the biochemistry involved in making archaebacteria lipids is very different from both eukaryotes and prokaryotes.  Their cell wall also contains something called an S-layer which is an intriguing structure.  Even more fascinating the flagellum they display is constructed differently from the flagellum of eubacteria.
1 Explore the structure of the archaebacterial monolayers.  How does this contribute to life in the extreme?
2 What is an S-layer and how does it contribute to cell function?
3 We discussed the problems inherent in trying to assemble a flagellum from pieces secreted from the eubacterial cell.  How is this problem solved in the archaebacterial flagellum? Or is it solved?


  1. 1. Explore the structure of the archaebacterial monolayers.  How does this contribute to life in the extreme?
    After some research, it seems to me that monolayer membranes undergo “conformational transitions”. This means that they automatically adapt to changes in temperature and solvents. These features are crucial for survival in extreme conditions.
    “Conformational transitions of these artificial membranes (which could be formed only above 70°C from a lipid/squalene dispersion) are analyzed in the 80 to 15°C temperature range... Results are consistent with the picture of a monolayer bipolar lipid membrane in which few solvent molecules align themselves parallel to the lipophilic chains. The amount of solvent as well as the temperature at which conformational transitions occur, depend on the solvent system in which the lipid is dispersed.”

    2. What is an S-layer and how does it contribute to cell function?
    In Archaeabacteria, the S-layer (composed of identical proteins) is the only cell wall component. It is crucial for mechanical stabilization. Other than providing mechanical stability, I didn’t find any other cell functions for the S-layer.

  2. 3. We discussed the problems inherent in trying to assemble a flagellum from pieces secreted from the eubacterial cell.  How is this problem solved in the archaebacterial flagellum? Or is it solved?
    Eubacterial flagellum have a Hydrogen ion or Sodium ion powered motor, shaft, and a propeller. Archaebacterial flagellum have a ATP powered motor and a shaft combined with a propeller. From the surface, it seems that the Archaebacterial flagellum is more simple. The bacteria already have a means of producing ATP and a shaft combined with a propeller seems more efficient and may require less steps to construct. BUT! This doesn’t seem to fix the secretion problem that results from producing flagellum. The Archaebacteria would still require the complex cap proteins that assemble the flagellum. I do think that the Archaebacterial flagellum would be easier to assemble. I do not think that the problem is completely solved.

  3. 1. The glycerol-ether lipids of archaebacteria is made of ether bond, which is proved more stable and resistance, that support archae to live extreme environment. Also, archaebacteria has isoprenoid sidechain that proctects archae from high temperature.
    2. Archaebacteria's S-layer is made of the protein from the surface layer of the cell walls to prevent macromolecules to interact with it. Archae's surface layer contains pseudopeptidoglycan that protect Archae from lysozyme.

  4. 1) The lipids of the archaebacterial membranes help them survive extreme conditions. The ether-linkages provide stability against breakage due to temperature. Also, the branching of the hydrocarbon chains decrease membrane fluidity. This allows the membrane to be stable in high temperatures.

    2) The S-layers serve as the sole cell-wall component or an outer layer in organisms with peptidoglycan. It acts as an extra permeability barrier and may posses antigenic sites.

  5. 1: I found that monolayers typically arrange themselves in the cytoplasmic membrane of bacteria, meaning that that they are found in unusual bipolar lipids. In the extreme thermophilic archaebacterium, the monolayer is apart of the structure contributing to the two polar heads connected by hydrophobic C(subscript)40. The way that this tightly packed monolayer is constructed in the bacteria gives reason for its stamina in extremely high temperatures.
    2: The S-layer, which is apart of the cell envelope in bacteria, is a layer that is composed of mainly proteins- which enclose the whole cell surface. However, the layers of proteins aren’t conserved very well because of their thickness, being between 5 and 25nm thick, it is easily damaged. However, when the S-layer is fully functioning, it has many functions that contribute to the function of a cell. Functions include: resistance against low pH, bacteriohages, phagocytosis, and also stabilization of the membrane. It also provides adhesion sites for exoproteins, which are extra proteins outside of the cell. All in all, the S-layer makes it easier for the bacteria to survive because of the protection that it creates.
    3: In similarity to what Erik said in his response to #3, I found that the flagellum found in Acrhaebacterial cells is powered by ‘ATPase’. They also contain a hook and a cap which gives way for the full length filament. However, besides this I couldn't really find anything else on them. Im having a hard time researching and finding quality information for the flagellum of the archaebacteria compared to the abundance of information for eubacteria. I can only conclude from this that that the knowledge of the flagellum in the archaebacterial cells is les than the flagellum in the Eubacterial cells.

  6. More on #3: Like Erik said, a cap protein would still be needed. But it appears that once the end of the flagellum is assembled and attached, there would be fewer problems with pieces needing to be contained in the same way as an assemble-from-the-end flagellum. So the problem is not solved but reduced, if you will.

  7. 1. The tails of the phospholipids of the membrane are fused (I think we learned that in class...). The resulting rigidity protects archaeans from extreme environments.

    2. The S-layer is a rigid arrangement of proteins that would protect that bacteria from physically and chemically harsh surroundings.

    3. Apparently some archaean flagella are hollow. Perhaps that is part of why they are assembled differently, like Sam said.

    The level of protection the archaen possesses is quite interesting considering it appears to have eukaryotic as well as prokaryotic genes. One may think eukaryotic genes would make it weaker in this regard or even wonder how those genes got there or why.

  8. #2 – Here is what I found on the S-layer: (from

    “S-layers are surface layers of bacterial cell walls. They are formed by two-dimensional, monomolecular crystalline arrays of identical units of protein or glycoprotein macromolecules (subunits).”

    Here is another source explaining S-layer function:

    “S-layer functions appear to be diverse. In order to judge the functional significance of S-layers, it is helpful to distinguish between primary and secondary functions. One of the basic functions is to protect cells against mechanical and osmotic stress.

    In archaea, S-layers are often the only cell wall structure and typically interact with the cell membrane via stalks that are inserted in the lipid (bi)layer. The S-layer imparts the cell mechanical stability and protects it against turgor and hypo-osmotic impact. The stabilizing effect can only be understood if the membrane-S-layer system is regarded as an integrated structure. Theoretical analyses suggest that small membrane bulges of S-layer unit cell size are formed upon internal osmotic pressure. These bulged membrane patches are much more stable than the naked membrane of (hypothetic) S-layer-less cells that will be dilated until leakages occur.”


    I can see how it would be especially helpful for archeabacteria that are halophiles to have an S-layer. A cell that lived in a high salt solution (e.g. NaCl) would need protection against dehydration (osmotic stress).

    For #3, Wikipidia gave some interesting information comparing and contrasting bacterial and archaeal flagella:

    “Bacterial flagella grow by the addition of flagellin subunits at the tip; archaeal flagella grow by the addition of subunits to the base. Bacterial flagella are thicker than archaeal flagella, and the bacterial filament has a large enough hollow "tube" inside that the flagellin subunits can flow up the inside of the filament and get added at the tip; the archaeal flagellum is too thin to allow this.”

    If flagellin is added to the base of the flagella, it is easier to keep track of. You may not even need to have a cap protein to keep the flagellin from floating away (since everything is contained at the base).

  9. 1. Archaea bacteria have plasma membranes that are only 4-5 nm thick but they are different from eubacteria in that they have isopranyl ether lipids: hydrocarbons that are linked to glycerol by di/tetraethar bonds. The glyceral diether bonds are associated with bilayer membranes while glycerol tetraethers are associated with monolayer membranes. The monolayer membrane has increased rigidity. The tails of two phospholipids are fused into a single molecule and this molecule has two polar heads. Since this membrane is more rigid it is better able to resist harsh environments. This type of membrane also serves as an excellent insulator, protecting the bacteria from outside influences.
    2. S-layer stands for surface layer and it is 2-dimensional built through self-assembly. It encloses the whole protein content of the cell. This layer often is the outermost layer of a cell and is what interacts with the outside world and acts as protection as well. In Archae it often serves the cell wall and works as a stabilizer.
    3. As has been said Archaeal flagellum are powered by ATP. They also are made of a bundle of filaments that rotate together, instead of separately as in eubacteria. The main difference in assembly is that the flagellum on eubacteria is built by adding subunits to the tip but in archaea it is built by adding subunits to the base. This could solve the problem right here, or as Sam said, reduce it. The proteins are not in the same danger is disassembling as they are in the eubacteria. Archaean bacteria flagellum is also much thinner than eubacteria.

  10. 1. Interesting how Archebacteria are the only ones to have this type of membrane yet they are still in Prokarya, as posted by many of my classmates the monolayers membrane is crucial to the Archebacterias survival in the extreme environments they are so fond of.

    2. The S layer is apparently the "armor" that allows the Archebacteria to survive in its environment

    Archebacteria although they are in Prokarya one cannot deny the fact that they are so unique that they should be classified as a different set of life forms they might be similar to Prokarya in some aspects (missing a nuclear membrane) regardless of their similarities we cant just deny that the monolayer membrane, their love for the extreme, containing DNA from both Prokarya and Eukarya and all the other differences we haven't yet discovered.

  11. 1. I was reading through some research and is it true that the structure is made of C-C bonds? If it does have a C-C bonds, then it's structure is quite strong!! This structure will last through many difficult conditions.
    2. An S-layer consists of monlayers with consistant proteins and glycoproteins as apart of the cell envelope. The S-layer in an archaea is useful for it's stabilization. this I don't think that the problem is completely solved, and I don't think God designed it to be. It reminds me of how we may never have everything in our lives played perfectly out, but God sure does solve many of them and make it right. :)

  12. This will be fun: We're used to thinking of Archaea as extremophiles b/c some can live in boiling water or the Dead Sea. But environmental genome survey sequencing has shown that there are many, many mesophilic archaeal species. Mesophiles live in the same environmental conditions as regular bacteria - that is, nothing special. In other words, if you went out to the ocean and sampled a handful of surface water, you'd probably find as many happy little archaea as bacteria. So how would that throw a monkey wrench in your ideas about archaeal membranes? Or does it?

    (See? Wasn't that fun?)

  13. These mesophilic archaea are significantly different from other Archaean’s. In fact, they are so different that a third phylum has been considered (Thaumarchaeota) to classify these mesophiles.
    “Based on the first genome sequence of a crenarchaeote, Cenarchaeum symbiosum, we show that these mesophilic archaea are different from hyperthermophilic Crenarchaeota and branch deeper than was previously assumed. Our results indicate that C. symbiosum and its relatives are not Crenarchaeota, but should be considered as a third archaeal phylum, which we propose to name Thaumarchaeota...”

    Yet, they still have the same glycerol-ether lipids in their membranes.
    ‘These differences may be an adaptation on the part of Archaea to hyperthermophily. However, it is worth noting that even mesophilic archaea have ether-linked lipids.”

    Maybe the difference between the mesophilic and extremophilic Archaeans lies with the S-layer?
    “Therefore, from comparative studies of mesophilic and extremely thermophilic S-layer proteins hints can be obtained about the molecular mechanisms of protein stabilization at high temperatures. First crystallization experiments of surface layer proteins under microgravity conditions were successful. Here, we report on the biochemical features of selected mesophilic and extremely archaeal S-layer (glyco-) proteins.”

  14. I don't think that this disrupts the ideas about the archaeal membranes because of the genetic differences between the mesophilic and extremophilic Archaeans. The mesophilic archaeans have probably just adapted to more mild climates.

  15. 1)I honestly think that "monolayer" is a bit of a misnomer. There are still two layers of lipids, they are just fused together. Thus, the monolayer provides more protection against the elements rather than less as its name implies. By the fusing of phospholipids,it makes it harder for molecules to exit and enter the cell. They are also able to stand higher temps because they are closer together. The molecules have less space to move around, so the layers don't drift apart as easily, leaving the cell naked.
    2) i read that an S layer is a crystalline layer of proteins on the outside of the cell. They are found in almost all archaeans, but they are also found in bacteria as well. In archaeans, they serve as the cell wall, but they also help with molecular transfer and attaching to other cells.
    3)It seems to me that archaeal flagella might be mor simple than bacterial. Archaeans generally have multiple flagella, where as one flagella suffices for most bacteria. Maybe because of the extreme conditions in which they live it helps for them to have smaller ore simple flagellum. after all, these flagella are not protected by a cell wall, and be able to function the way they're needed. however, what Dr. Wood says about archaea kind of screws with this theory. :/ why would mesophilic archaea need different flagella? i have no clue.

  16. Well...after googling S-layer and getting a bunch of links to SLAYER, I found an oxford journal that explained some known functions of the surface layer as protection, framework, and adhesion to other cells.

    About the archaeal membranes...I was thinking that maybe the archaeans did not used to live in the mild environments that they do now, which is why they can live in both extreme and mild habitats, OR maybe the mild habitat had once been an extreme one?? So...basically it narrows down to adaptation that Erik said... :/ Sorry, my thoughts seem original at the time but...nothing is new under the sun. haha

    -Sarah Gonzales

  17. 3. Unlike Bacterial flagellum which need protein caps to build the flagellum, the aerchaebacterial flagellum grow by the addition of subunits to the base. The Bacterial flagellum is formed by the pushing of proteins through its hollow shaft to the tip, but the archaebacterial flagellum’s shaft is to thing for this to occur. One of the reasons why bacteria need the protein cap is that if it was not there, the proteins shot up through the shaft to the tip of the flagellum, would shoot out the end and would be lost. But this problem is not present with the archaebacterial flagellum. Because it grows by adding proteins to the base and pushing it outward, protein caps are not needed. This seems to be an easier method and more likely to happen in evolution. Thus the formation seems to be simpler than that of the bacterial flagellum, providing some viable evidence that the evolutionists are simply overjoyed to flaunt in the Creationists’ faces. This is done in the book “Why intelligent design fails: a scientific critique of the new creationism” by Matt Young and Taner Edis.

    Source: The New World Encyclopedia

  18. to answer toddcwood,
    does this really matter? just because they are known for being extremophiles, there can be exceptions. There are always exceptions to the rules that scientists come up with to classify species. Archaens do have the ability to live in extreme conditions, but does that mean that they HAVE to be living in extreme conditions? The Mesophiles do live in normal environments, but that means that they have the sufficient membranes to live in their habitat, where they were created and designed to live in. To me this doesn't seem to be that much of a problem.

  19. my answers for questions 1-2 keep on getting erased for some reason, even though I keep posting them... if the blog is flooded by my answers, then I guess you'll know why

  20. 1. Archaebacterias’ phospholipid membranes are different than that of the bacteria and eukaryotes in many different ways.
    a. The bonds that bond the lipid to the glycerol are ether bonds (the others have ester bonds). Ether bonds are chemically more resilient to extreme conditions such as highly acidic or extreme cold/ hot environments.
    b. The archaens’ lipid tails are chemically different than those of bacteria and eukaryotes. They are based on isoprenoid side chains and are long chains with many side branches. Only archaens use isoprenoids to make their phospholipids. These branched chains on the glycerol tails may prevent the archaen membranes from leaking in high temperature environments.
    c. Some archaens do not have lipid bilayers but a lipid monolayer. The tails of two phospholipids fuse forming a single molecule with two polar heads. This makes the membranes more rigid and better to resist harsher environments and habitats.

  21. the website still won't let me post my answer to question 2.

  22. 2. The S-layer is the part of the cell membrane that is formed by a single layer of proteins or glycoproteins (the layer is a single layer of one type of protein). This S-layer surfaces the entire cell. The latticed shape of the layer can consist of one, two, four, three, or six identical (glyco)protein subunits. The hexagonal symmetry is the more prevalent in archae.

  23. finally got it all through after 30 mins of trying to post this

  24. 1. The archaean's membrane is similar to a bilayer, except the polar tails are connected. This may help them survive in extreme environments; as this kind of arrangement makes the membrane more stiff and may help it in these conditions.
    2. The S-layer is a layer on the outside of the membrane that is covered with proteins. These proteins are suggested to provide immunity against other bacteria, as well as resistance to extremely low pHs.
    3. Whereas flagella in eubacteria involves adding subunits to the tip of it under the guidance of a cap protein, the flagella in archaeans adds the subunits to the base of the flagella.

  25. The archebacterial monolayers contribute to the tolerance archae have for extreme conditions in many ways. One way they survive is by have ether bonds which are more stable and may help the archae survive in extreme conditions. Another way is in a monolayer the phospholipids fuse forming a single molecule with two polar heads which may make the membrane more rigid and resistant to extreme environment.

    An s-layer is a rigid wall of protein molecules that cover the cell providing even more protection for the archae.

    The flagellum do not grow quite the same as bacterial flagella. They grow from the base of the flagella in what is called a "polar cap."

  26. I do think that the mesophillic archael species is incredibly important in just posing a whole bunch of other questions for us scientist who think that we have it all figured out. The fact is that we do not have it all figured out because God has made creation complex and unique and incredible.

    Archaens are generally bacteria that can live under extreme conditions and are thus thought to be the "first form of organisms," but now that some are found in not so harsh conditions, it might prove that maybe the early theories on the early days of earth are wrong. It could possibly point to a creation model.

  27. 1. It seems that my classmates have said enough about this topic. However, David, I was reading Wikipedia, and it seems to advocate a third domain for archaeans. I think this idea might be fairly new and has probably not caught on much. I know that last semester Dr. Englin only taught the normal 2 domains, so he probably had a good reason for this. However, I do understand those who say that there should be a third domain, because the archaeans are similar but different in so many ways.

    2. Wikipedia says "In most archaea the wall is assembled from surface-layer proteins, which form an S-layer.[62] An S-layer is a rigid array of protein molecules that cover the outside of the cell (like chain mail)"

    This layer acts like armor that would help them live in extreme conditions. And since we now know that archaeans do not live in only extreme places, I was thinking that since they only have a monolayer (as opposed to a bilayer) this outer armor helps protect them more from predators and other things trying to get into them.

    3.Definition of Archaeal flagella: "Archaeal protein present in or involved in the biogenesis or function of a flagellum, a long hair-like cell surface appendage made of polymerized flagellin with an attached hook. This rotating structure with switches propels the cell through a liquid medium. The archaeal flagellum is distinct from its bacterial equivalent in terms of architecture, composition and mechanism of assembly. Thinner (10-15 nm) compared to the bacterial flagellum (18-24 nm), it is usually composed of several types of flagellins and is glycosylated. The archeal flagellum is considered as a type IV pilus-like structure."

    So it seems that it has different types of flagellin than eubacteria's flagella and is much thinner. I wonder if the thinness of the flagella helps archaeans live in more harsh conditions?!?

    In response to Dr. Wood's point, it seems that if the evolutionists want to say that archaea was around at the beginning of the earth, because it was a very harsh environment, then they would also have to deal with the types of archaea that live in more mild places. They might try to argue that the extremophiles came before the ones that live in more mild conditions, but at this point I don't know enough to say that they are too similar than for them to evolved. It does seem to all point to a creationist perspective, though.

    Hopefully this makes sense, there are so many ideas going through my head I probably didn't say it as clearly as I am thinking it now...

  28. If archeal membranes can survive in extreme conditions it is logical to think that they would also be useful in environments that aren't actively trying to destroy the cell. If the cells can survive in hellish conditions wouldn't they also survive in any other environment. My question is it practical for them? is it as good in those conditions as it is in normal environments? I think it is like having a tank as a car it can take a lot of punishment but is the 4 inch reinforced steel really needed for suburbia?

  29. 1. Explore the structure of the archaebacterial monolayers. How does this contribute to life in the extreme?
    Archae with single monolayers fuse the tails of two phospholipids into one molecule with two polar heads. This fusion helps the membrane be more rigid and better able to resists harsh environments, such as the acidic environments in which Ferroplasma live. Tetraether-linked membrane monolayers in Ferroplasma give these archaebacteria a stronger tolerance to acid and large metal ion gradients.
    2. What is an S-layer and how does it contribute to cell function?

    An S-layer is a structure made of identical protein or glycoproteins that encloses the whole cell surface. The S-layer is important because if bacteria does not have a cell wall it is the part of the cell that receives the most interaction. In this way it can act very much like a cell wall in archaea that don’t have a cell wall. The S-layer then serves as a mechanical stabilizer. S-layers have also been found to be virulence factors against certain pathogens. They also aid in adhesion as well as resistance against low pH.

    3. How is this problem solved in archaebacterial flagellum? Or is it solved?
    This problem is somewhat solved in that archaeal flagella grow by the addition of subunits to the base. Bacterial flagella grow by addition of flagellin subunits at the tip. The bacterial feat is much more difficult since the bacteria excretes these proteins and lets them float in the exocellular fluid yet it is still able to control them and build flagella. Even though archae bacteria add to the base, the process of forming a flagella is still extremely complicated and therefore points to a Creator.

  30. 1. The structure of the archeabacterial monolayers helps the membrane allow to survive in harsh environments, adaptation like our survival in homeostasis.
    2. And S-layer is a cell envelope composed of identical proteins and glycoproteins, and it encloses the whole cell surface. It contributes to the cell function by being self assebled, being a cell wall, and then acting as a stabilizer.
    3. The problem I guess could be in the flagellin. It has subunits at the tip of the protein. I read that it also involves the ATpase to help energize it.

  31. 1. The monolayer membrane of archaebacteria is really more like a bilayer that has lipids fused together to form one molecule with two polar heads. This allows the membrane to hold together even in extreme heat. The teatraether linked layers that Kayla just mentioned porobably help archeans survive in extremely salty or acidic environments as well.
    2. The S-layer is a self-assembled cell wasll of proteins that surrounds the membrane and porvides further protection to the membrane. S-layer walls differ from traditional bacterial cell walls in that they lack peptogylicagan.
    3. Archean flagella are assembled by secreting subunits from the base of rather than through a pore at the tip where a protein assembles it. My guess is that since archeans tend to live in environments that can cause a protein outside of the cell to denature, that step needed to be bypassed.

  32. 1. When the lipid bilayer is replace by a lipid monolayer, "the archaea fuse the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments." (
    If the tails are fused to make an even more rigid membrane then it is hard for anything to break them apart and this makes the membrane more resilient to being broken up by heart, acid, salt, and many other extreme environments or situations. A bond between the phospholipids that pretty much makes them all one molecule is very advantageous in environments that tend to break up membranes with more ease.
    2. The S-layer encloses the cell's whole surface and it is 2 dimensional, so very thin. But it has so many functions for such a small layer. "The S-layer represents the outermost interaction zone with their respective environment. Its functions are very diverse and vary from species to species. In Archaea the S-layer is the only cell wall component and, therefore, is important for mechanical stabilisation. Additional functions associated with S-layers include:
    protection against bacteriophages, Bdellovibrios, and phagocytosis
    resistance against low pH
    barrier against high-molecular-weight substances (e.g., lytic enzymes)
    adhesion (for glycosylated S-layers)
    stabilisation of the membrane
    provide adhesion sites for exoproteins
    provide a periplasmic compartment in Gram-positive prokaryotes together with the peptidoglycan and the cytoplasmic membrane" (
    3. Bacterial flagellum grow from addition of flagellin to the tip but archaebacterial grow with additions at the base, so rather the building blocks on top of each other it is like building something from the top down and pushing it out as it becomes more complete. I think that the main difference in which a problem could be corrected is in the way that the bacteria is built by additions of flagellin to the base instead of building up from the tip.

  33. 2)S-layer is a part of cell envelope of achaea. It composed of identical glycoproteins and up to six identical protein subunits. It has hydrophobic anchor. S-layer provides protection against bacteriophages, resists low pH and stablizes the membrane.

  34. The lipids in the archeabacteria are different than lipids in other cells. These lipids have a reversal of the glycerol and have ether instead of ester linkages. They also contain a unique side chain which spans the membrane. These lipids unique formation allow each lipid to covalently bond to one another instead of amphipathic interactions.

    An s-layer is an integrated structure that protects the cell against different kinds of stress. Its construction is a rigid layer of proteins that cover the membrane. This feature allows archeabacteria to withstand extreme conditions.

    The flagella in archeabacteria are constructed by adding subunits to the base whereas bacteria go through a tube and then are arranged. Although archeabacteria seem to have a simpler flagella construction mechanism, it still seems to be reducibly complex. A cap protein might possibly be needed to arrange the flagella but since it is constructed from a base on the outside, it seems that the subunits would already be floating around. It does make sense though that a protein ‘helper’ would be needed to arrange the flagella.

    Concerning Dr. Wood’s question, it seems to me that this membrane theory would remain the same. The special s-layer and the unique lipids allow the archeabacteria to live in extreme environments by providing protection from these conditions. This doesn’t mean that these specializations would hinder its abundance in a natural environment, it would just be an added luxury that is no longer needed.

  35. I think the archaebacterial monolayers are adaptive by nature. As life in the extreme can be very unpredictable, adaption is probably the most significant reason as to why the structure is valuable.

    Also, I believe the S-layers functions more like an envelope or outer layer that performs the kinds of roles that you would expect an outer layer to except that it has a few other functions, as Nha already states, such as resistance to low pH and membrane stabilization.

  36. some functions of the S layer are:
    protection against bacteriophages,resistance against low pH, barrier against high molecular weight substances,adhesion,stabilization of the membrane, provide adhesion sites for exoproteins, provide a periplasmic compartment in Gram-positive prokaryotes...

  37. 1 Explore the structure of the archaebacterial monolayers. How does this contribute to life in the extreme?
    AFter researching the structure of the archaebacterial monolayers, it seems that in some archaebacteria, the lipid layers are replaced by the monlayers. Monolayers are closely packed layers of cells or molecules. So in the case of the archaebacteria, the archaea fuse the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments. This makes sense in the fact that this bacteria can function in extreme cases because they have formed these rigid structures to protect themselves.

    2 What is an S-layer and how does it contribute to cell function?
    The S-layer is a part of the cell envelope, and encloses the whole cell surface. It is composed of a monomolecular layer composed of identical proteins or glycoproteins. This layer has many functions of contributing to cell function such as: protection against bacteriophages, Bdellovibrios, and phagocytosis. It also functions as resistance against low pH, stabilization of the membrane, and it provides adhesion sites for exoproteins.

    3 We discussed the problems inherent in trying to assemble a flagellum from pieces secreted from the eubacterial cell. How is this problem solved in the archaebacterial flagellum? Or is it solved?
    IT seems that this problem being reduced in that the archaeal flagellum appears to grow at the base rather than the tip.This seems more simplistic in forming the flagella. Because it is first attached at the base of the cell not out in the cellular fluid.

  38. 1 Explore the structure of the archaebacterial monolayers. How does this contribute to life in the extreme?
    The membrane ofCaldariella acidophila, an extreme thermophilic archaebacterium, is characterized by unusual bipolar complex lipids. They consist of two nonequivalent polar heads, linked by a C40 alkylic component. The molecular organization of these lipids in the plasma membrane is still a matter of study.

  39. 1.) Since archaebacteria are known to be extremophiles, the membrane of the archaebacteria have to be strong. The phospholipids of archaebacteria are joined to the phosphate head by ether linkages. Ether linkage is more resistant to extreme conditions.
    2.) S-layer, short for surface layer, is part of the cell envelope found in bacteria and archaea. It consists of a monomolecular layer made up of identical proteins or glycoproteins. It is the outermost cell wall layer in many prokaryotes. The S-layer contributes to cell function such as stabilization of the membrane, protect cells against mechanical and osmotic stress, compartmentalization, and shape maintenance.

  40. 1 since we is it known that in extremophiles, is archaea bacteria which are joined to the top of the phosphate by linkages which are resist to extreme conditions.
    2 Archaeans which are mainly composed of generally bacteria to resist the hard condition inside of the cell they have proteins attached to the outer membrane it seem that they provide immunity support for the cell the Archaeathis is also km=nown as the S layer which is part of the cell envelope which lives in achaeana

  41. It seems that the monolayers arrange themselves in the cytoplasm and adjust to certain conditions such as temperature themselves by
    “monolayers showing a reversible collapse at surface pressure as low as 22 dynes/cm. his collapse pressure decrease with temperature in such a way that the film tension remains constant. At room temperature, the monolayer presents a more condensed state, probably due to the lateral cohesion between long alkyl chains, but a lower collapse pressure.” (Monolayers of ether lipids from archaebacteria R. Rolandi).
    The S layer is said to be important for the incorperation of new morphological units and cell division and is made of aporus, interconnected network. Its said that the flagellum moves from base to tip for motion.

  42. 1 Achaean membrane is made of molecules that differ strongly from those in other life forms. In all organisms cell membranes are made of molecules known as phospholipids. These molecules possess both polar parts that dissolve in water which is the phosphate head, and a non-polar part that does not dissolve in water called the lipid tail. These dissimilar parts are connected by a glycerol moiety. In water, phospholipids cluster, with the heads facing the water and the tails facing away from it. The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer. This contributes to life in extreme because the Archaeal lipid tails are chemically different from other organisms. Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings.
    2 An S-layer is a rigid array of protein molecules that cover the outside of the cell. This layer provides both chemical and physical protection, and can prevent macromolecules from contacting the cell membrane. Unlike bacteria, archaea lack peptidoglycan in their cell walls. This obviously contributes to the cell for protection.
    3 Archaea flagella operate like bacterial flagella. Their long stalks are driven by rotatory motors at the base. These motors are powered by the proton gradient across the membrane. Archaeal flagella are notably different in composition and development. Bacterial flagellum is hollow and is assembled by subunits moving up the central pore to the tip of the flagella, archaeal flagella are synthesized by adding subunits at the base. It’s a problem because the motors and all the pieces are constantly moving and very hard to obtain. The flagellum is constantly moving so it’s hard to figure out.

  43. 1. Archaea have membranes composed of glycerol-ether lipids, which are chemically more resistant than other bonds. This stability might help archaea to survive extreme temperatures and very acidic or alkaline environments. “Archaeal lipid tails are chemically different from other organisms. Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings.” “These branched chains may help prevent archaean membranes from leaking at high temperatures.” (wiki) The monolayer itself is the fusion of the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments.
    2. The S-layer (surface layer) is a part of the cell envelope. It consists of a monomolecular layer composed of identical proteins or glycoproteins. This two-dimensional structure is built via self-assembly and encloses the whole cell surface. For many bacteria, the S-layer represents the outermost interaction zone with their respective environment. Its functions are very diverse and vary from species to species. It has many functions, some of which are: protection against bacteriophages, Bdellovibrios, and phagocytosis; resistance against low pH; stabilisation of the membrane; and provides adhesions for various functions.
    3. Archaeal flagellum appears to grow at the base rather than the tip. Archaeal flagella are almost certainly powered by ATP, while bacterial flagella are powered by a flow of H+ ions (or occasionally Na+ ions). While bacterial cells often have many flagellar filaments, each of which rotates independently, the archaeal flagellum is composed of a bundle of many filaments that rotate as a single assembly. These differences of features could mean the archaeal flagellum are more efficient and easier to build, especially since it seems to grow from the base. Growing from the tip is more complicated and requires more proteins. Whether this means it “solves” the problem or not, I am not sure.

  44. First of all a cockatrice sounds pretty good, it sort of reminds me of a delicacy we have back home in the Philippines.

    Just like how S-layers are made of proteins that protect the cell, a cockatrice has a pork and a poultry layer, which is high in protein too. In archaebacteria you have this like wall structure, just like the cockatrice. If the turkey was stuffed into the suckling pig, or vice versa which ever was the small or bigger one. It would have resulted to a double layer of food. Crispy skin, meet, skin, meet.

  45. 1. Basically, archaebacterial monolayers are more rigid than a regular phospholipid bilayer and therefore can stand more intense temperatures than a regular cell. This has to do with how the molecules that form the monolayers bond together. They have two polar heads as well, I feel like my answer is sporatic, but...thats the gist of it.

    2. The S layer is part of the cell envelope, serves a different purpose than the monolayers. It is on the very outside of the cell, almost like a force field between the membrane and the outside world. Perhaps this S layer is stronger than the membrane, or maybe its pores are a bit thicker, so block the bigger bacteria from entering the cell.