Kingdom Monera

Kingdom Monera historically included the bacteria, blue-green algae (cyanobacteria or blue-green bacteria), and the archaebacteria 

Characteristics of the Monera Kingdom:

• Prokaryotes, microscopic
• Heterotrophic and autotrophic
• (Heterotrophic - Organism that  can't synthesize (make) it's own    food)
     (Autotrophic - Organism that can  make it's own food
• Anaerobic and aerobic aquatic, terrestrial

·         The kingdom Monera includes the most ancient, the smallest, the simplest and the most widely distributed group of living organisms that are generally described by the term prokaryotes.

·          

·         The kingdom includes two sub kingdom namely

·         1.Archaebacteria: It consists of ancient bacteria

2.  Eubacteria: It consists of the:

                                     i. true bacteria

                                    ii.blue green algae / cynobacteria

v  mostly asexual

v  mostly non motile (1 form does  move)

Archaebacteria:

v  "ancient bacteria"  on earth for billions of years,

v  Prokaryotes

v  are autotrophic or heterotrophic

v  others are chemoautotrophs

v  they are mostly anaerobic

v  they have no peptidoglycan in their cell walls.

v  the RNA of their ribosomes is different to that of Eubacteria ribosomes (like those of eukaryotes).

v  plasma membranes with unusual fatty acids

v  They are known as extremophiles, as they are able to live in a variety of extreme environment :

   1.some are methanogens

   2.some are extreme thermophiles

   3.others are extreme halophile (salty pond)

    Eg. Sulfolobus sp.

DNA contains a single, circular molecule, which is compact and tightly wound.No protein is associated with DNA.They differ in terms of ribosomal structure, the possession of introns and in membrane structure or composition.They are similar to eukaryotes in ways that archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes: notably the enzymes involved in transcription and translation.

a) Archaebacteria - under harsh/extreme conditions

1.  Thermophyles / Thermoacidophyles

Thermophiles live in places that have high temperatures, such as hot springs with          temperatures above 60°C (up to 110°C forhyperthermophiles!) or near or below freezing.
Thermophiles live in hot sulfur springs, Yellowstone Park,

2.Halophyles  sometimes known as Halobacterium live in extremely saline environments .       -Require an environment as saltyor even10x saltier than ocean  water.Some prefer up to 30% salt concentrations                               

3. Methanogens                                                                                                                                   Methanogens live in anaerobic environments and produce methane gas; swamp sewage.

Eubacteria: includes bacteria and blue green algae, both of which possess prokaryotic cells.

General characteristic of eubacteria.

v  Lack distinct nuclei and other membraneous organelles

v  Cell wall made of peptidoglycan

v  Some have a flagellum

v  Live in many places eg. As parasite or simbion.

v  The bacteria of kingdom eubacteria

    a. heterotrophic,

                   b. autotrophic,    and

                   c. chemotrophic.

v  Heterotrophs absorb organic materials down in both living and dead organisms.

v  Saprobes feed off of non -living organisms and recycles  organic compound

v  Autotrophs- obtain energy through photosynthesis.Most are a blue-green color and are often called blue-green bacteria. They get this color from chlorophyll.They live in chains in ponds, lakes, and moist regions.

v  Chemoautotrophs -get their food by breaking down inorganic matter. Example are nitrifying bacteria,

 cyanobacteria, (some decomposers, some pathogens)
Body type: unicellular
Prokayotic / eukaryotic: prokaryotic
Environments: extreme environments as archaebacteria (near volcanic activity)

3 ways to classify bacteria:

(a).the shape of bacteria

(b).based on gram staining

(c).based on the position of flagella

(a).based on the shape  of bacteria

Bacteria are prokaryotic and are found in the Kingdom Monera. 

Bacteria are very small, and, do not contain membraneous cellular organelles except for  ribosomes.

They have DNA, but it is contained in a nucleoid, which has no nuclear envelope.

Because of this, bacteria are said to be lack of true nucleus.

Many bacteria have rings of DNA called plasmids, which are often used to carry foreign DNA into other bacteria for recombinant DNA engineering.

Bacteria exist in three different shapes,

      coccus (round),

      spirilla (spiral),

      baccilla (rod).

Bacteria have simple balloon-like shapes (spheres, rods, spirals) which are determined by the way the cell wall is formed. There are just a few basic bacterial shapes,ranging from spheres to rods to spirals. The bacteria maintain their shape by osmotic pressure.

(b).TYPE OF BACTERIA BASED ON GRAM STAINING

Gram-positive bacteria are those that are stained purple or violet by Gram staining.

Characteristics of Gram-positive bacterium:

•       cytoplasmic lipid membrane.

•       thick peptidoglycan external to the cytoplasmic membrane.

                                      

GRAM NEGATIVE BACTERIA

•       The following characteristics are displayed by Gram-negative bacteria:

Ø  Cytoplasmic membrane

•       Thin peptidoglycan layer (which is much thinner than in Gram-positive bacteria) located between the cytoplasmic membrane and a second outer membrane.

•       This  space between the layers of peptidoglycan and the secondary cell membrane is called the periplasmic space

•       Outer membrane containing lipopolysaccharide ( outside the peptidoglycan layer)

•       Porins exist in the outer membrane, which act like pores for particular molecules

Flagella of bacteria

These are the organs of motility. Flagella are composed of flagellins (proteins) that make up the long filament. This filament is connected to a hook and rings that anchor the flagella in the cell wall.  Assembles at external end.

Can be arranged in two ways: 

1) polar flagellation:

flagella attached at one (monopolar) or both (bipolar) ends. Ex: Pseudomonas aeruginosa

2) peritrichous flagellation:

flagella attached at many sites around cell periphery. Ex: E. coli

The economic importance of bacteria 

-The economic importance of bacteria includes both their useful and harmful aspects.

 1.Harmful bacteria/ pathogenic

 Some bacteria are harmful and act either as disease-causing agents  (pathogens) both in plants and animals, or may play role in food spoilage. Eg. Parasitic bacteria in human Helicobacter pylori cause infection in lining of stomach and result in peptic ulcers.

 2.Useful bacteria

  a.Recycling of chemical elements in ecosystem

-bacteria play a major role in recycling many chemical elements  and chemical compounds in nature.    

-Bacteria speed the decomposition of dead plant  and animal matter.

-Bacteria play a key role in making soil fertile through nitrogen fixation. They convert nitrogen in Earth’s atmosphere into the nitrogen  compound ammonia, which plants need to grow.

 -The bacteria the only organisms able to fix atmospheric nitrogen usually   live in association with plants, through mutualistic interaction  often  integrated into the plant tissue

  Bacteria in the genus Rhizobium, for example, form nodules (knobs) on   the roots of beans and other plants in the legume family.

b.Symbiotic Intestinal Bacteria,

Also known as Gut Flora are organisms that live in our intestines and keep us healthy. E. Coli   live in human intestine where the bacteria  get a place to live and obtain food source. In return it help human by aiding in digestion and producing vitamin K and B12 required to build blood components

c. Genetic engineering and bacteria

Genetic engineering is the manipulation of genes. It is also called recombinant DNA technology.Using biotechnology techniques, bacteria can also  be bioengineered for the production of therapeutic proteins, such as insulin, growth factors or antibodies

 Bacterial cells are transformed and used in production of commercially

     important products

    i. Oil spill treatment.

        Bacteria are used to clean up oil spill release by

        human into the environment due to human activities.

    ii. production of human insulin (used against diabetes), 

    iii.human growth hormone (somatotrophin used to treat pituitary

        dwarfism),    

    iv. Infections which can be used to help fight viral diseases.

    iiv.In sewage treatment , bacteria digest soluble organic ecompound to

         produce CO2, H2O and methane gas.

   

Characteristics of

Cyanobacteria/ blue green algae
1. The cyanobacteria are the largest and most diverse group of photosynthetic bacteria, which was previously known as blue green algae.
2. Cyanobacteria are true prokaryotes.
3. They vary greatly in shape and appearance.
4. They range in diameter from about 1 to 10 micron.
5. They may be unicellular and exist as colonies of many shapes, or form filaments  called trichomes.
6. They have normal Gram-negative type cell wall.
7. They carry out oxygenic photosynthesis i.e., they use water  as an electron donor and generate oxygen during photosynthesis.