Question

1. What are the major problems faced by Acidophiles?
2. How do the extreme conditions affect the following in Acidophiles: cell wall construction/components, membrane components and fatty acid structure, transport of materials in/out of the cell, protein/enzyme structure, and metabolism (especially the electron transport chain). Explain 3 of these in-depth.
3. Find one interesting organism (eubacteria or archaeabacteria) from the acidophile group and describe where they live and how they survive in this environment.

Answer 1

Answer-

Acidophiles or an acidophilic organism includes eukaryotes, bacteria and certain archaea who are surviving in tough acidic conditions at pH 2.0 or below. These organisms adopts in this acidic environments By pumping out protons from the intracellular space to keep the cytoplasm near neutral pH.

• Acidophiles use several mechanisms including   reversed membrane potential, cytoplasmic buffering and proton impermeable cell membrane.

• acidophiles cell membrane made up of  different concentration of fatty acid and lipid composition they have pres  tetraether lipids in their membrane helps in countering the acidic environment.

• they use a reverse membrane potential mechanism (positive ∆Ψ) for the maintenance of pH, there are several cation transporters are present in acidophiles, usually potassium, inhibits the entry of protons into the cell.

• acidophiles have proton efflux system that includes H⁺ ATPases, antiporters and symporters types of proteins

• acidophiles are characterised by presence of low organic substrate inputs and high concentrations in inorganic substances, such as sulfur compounds and iron molecules.

• acidophilic organisms overcome the  effects of low pH and high osmotic stress, by producingseveral types of compound which are serve as osmo-protectants and protect them and maintain the integrity of cell membrane.

• Acidophiles are exposed to very highly oxidizing conditions such as high level of reactive oxygen species and they overcome this problem by several ROS scavenging enzymes, and maintained the integrity as well as normal composition of cellular environment.

• acidophilic archaea mostly have habitat in volcanically-active regions (sulfur-rich) and metal rich area ,and grow in the form of streamers, slimes, and microbial stalactitesand are sulfur-, hydrogen- and iron-dependent.

• Acidophilic microorganism induce a biogeochemical cycling of micro nutrients by catalysing the transformations of iron and sulfur molecules and  generate electron donors as well as electron acceptors to survive in  low pH environments.