SOIL MICROBIOLOGY

 Microbes in cell

Microbes:

Microbes are tiny living organisms that are too small to see by our naked eye. There are diverse groups of microbes which are

• Bacteria: single celled organism with no nucleus can be found anywhere from soil to human digestive system.
• Archaea: These are similar to bacteria but with different genetic and biochemical pathway. Many archaea can survive and live in extreme conditions.
• Fungi: Can be single or multicellular plays a major role as decomposers in soil and used in food productions.
  
• Protists: A group of eukaryotes with a nucleus it includes algae.
• Viruses: Nonliving organism under microbes which replicates inside the host cells.
  

Microbe interaction with cell

• Beneficial: Both gets benefited in this relationship like mutualism.
• Harmful: One gets harmed or killed in this process, while other gets benefitted in this.
• Neutral: No harm or benefit to both cell and microbes in it.

Importance of microbes in cell

• Nutrient Cycling: Microbes break down the complex material and releases the nutrients in the soil.
  
• Decomposition: The fungi act as decomposers and decompose dead matter into the soil
• Disease suppression: Some microbes can suppress the plant disease by inhibiting the pathogens or by producing antimicrobial compounds.
• Soil Structure: microbes contribute to bind the soil and maintain the structure of soil by aeration and water filtration.

Diversity importance in soil Microbes

• Functional Redundancy: The diverse community of microbes in soil can perform same functions it helps to maintain the function even if one microbe is taken from the diversity.
• Resilience: Many microbes in the diversity in the soil are resistant to pH, temperature and moisture in soil, A diverse community helps to build resistance and survive in extreme conditions.
• Ecosystem Services: Different microbes in diversity helps in various functions such as decomposer, nutrient cycling and to help in maintaining the soil structure.
  

Themophytes

Derived from Greek "Thermos" means heat and "Phyton" plants. It includes many organisms such as

• Bacteria.
• Archaea.
• Algae

Habitat of Thermophytes:

1. Hot springs.
2. Hydrothermal vents.
3. Volcanic areas.

Adaptations:

• Heat-stable proteins: Their protein helps it to prevent from unfolding and denaturation at high temperatures.
  
• Specialized cell membranes: The cell membrane is made up of lipids which are stable at high temperature.
• DNA repair mechanisms: The DNA repair mechanisms is efficient at repairing DNA damage caused by high temperature.

Psychrophytes

Derived from Greek means cold plankton the organism includes

• Bacteria.
• Algae.
• Plants.
• Fungi.
• Archaea.

Habitat of Psychropytes:

1. Polar regions.
2. High-altitude environments.
3. Glaciers and ice sheets.
4. Snowfields.
5. Deep seas.

Adaptations:

• Cold-active enzymes: Their enzymes work at cold temperatures and carry out the metabolic process.
  
• Antifreeze proteins: These proteins help prevent damage to cell due to formation of ice crystals over cell.
• Accumulation of cryoprotectants: The use of sugars and polyols to protect from cold temperature and to prevent cell damage.
  

Radiation tolerance

The radiation like UV, X-Rays, Gamma damage the DNA or mutates the cell or leads to cell death. The organism with radiation tolerance can survive the radiation the mechanism in it protects it and repairs the damage by radiation.

Radiation Tolerance Organisms:

•  Deinococcus radiodurans: A bacterium that has high radiation tolerance. It can withstand doses of radiation thousands of times higher than what would be lethal to humans.
• Thermococcus gammatolerans: An archaeon that can withstand more radiation than bacterium Deinococcus radiodurans.

Mechanism of radiation tolerance:

1. DNA repair: The repair mechanism is highly efficient and quickly repairs the damage by radiation.
   
2. DNA protection: The protein that binds to DNA protect itself from damage of radiation.
   
3. Antioxidants: The production of high antioxidant protects it from free radicals that causes cellular damage.

Metallophiles:

The metalophilles are extremophiles which can survive in extreme conditions. It can survive in heavy metal contamination areas. The heavy metals include

1. arsenic.
2.  cadmium.
3.  chromium. 
4. copper.
5. lead.
6. mercury.
7. nickel and zinc.

Habitat of Metallophies:

• Contaminated soils.
• Hydrothermal vents.

Adaptations:

• Metal exclusion: The organism prevents entering of heavy metals by using cell wall as protective barrier or by pumping it out.
  
• Metal binding: The proteins produced by organism can bind with the heavy metals.
• Efflux pumps: The proteins that actively transport the heavy metal outside the cell preventing excess toxicity inside the cell.

Acetophiles

Acetophiles are one of extremophiles lives in high acidic environment, they are used in production of vinegar.

Habitat of Acetophiles:

• Fermented foods.
• Acidic soils.

Adaptations:

• Acid-resistant cell membranes: The cell membranes are structured to tolerate high acidic conditions.
• Intracellular pH regulation: The mechanism helps to maintain neutral pH inside the cell while in acidic environment.
• Acetic acid metabolism: The metabolic pathways tolerate the high acidic environment and helps in acetic acid productions.
  

Alkaliphiles

Alkaliphiles are extremophiles they survive in high pH and alkaline conditions.

Habitat of Alkaliphiles:

• Alkaline soils.
• Hot springs.
• Deep-sea vents.

Adaptations:

• Alkaline-stable cell membranes: The cell membrane are structured to function in high alkaline conditions.
• Enzymes that function at high pH: Their enzymes work in high pH environment that carries out the metabolic pathway.
  

Halophiles

Halophiles are microorganisms (mostly archaea and some bacteria) that live in environments with high concentrations of salt.

Habitat of Halophiles:

1. Salt lakes.
2. Salt mines.
3. Evaporating ponds.

Adaptations:

• Salt-resistant enzymes: Their enzymes are specially adapted to function in the presence of high salt concentrations.
• Specialized cell membranes: Their cell membranes are often more rigid and stable, thanks to unique lipids, to withstand the harsh osmotic pressure.