bacterial capsule

Examples of bacterial capsule in the following topics:

• Glycocalyx

  • The cell capsule is a very large structure of some bacterial cells.
  • Most capsules are difficult to stain using standard stains because most stains do not adhere to the capsule.
  • They also exclude bacterial viruses and most hydrophobic toxic materials such as detergents.
  • The slime layer is not to be confused with the S-layer, a separate and highly organised glycoprotein layer surrounding many bacterial cells.
  • This diagram depicts the different types of glycocalyx. 1) Bacterial capsule is a well-organized layer outside the cell. 2) Slime layer is diffuse and irregular in structure. 3) Bacteria can form biofilms by fusing their glycocalyxes.

• Bacterial Transduction

  • At the same time, some phage genes are left behind in the bacterial chromosome.
  • Generalized transduction is the process by which any bacterial gene may be transferred to another bacterium via a bacteriophage, and typically carries only bacterial DNA and no viral DNA.
  • In essence, this is the packaging of bacterial DNA into a viral envelope.
  • The new virus capsule, now loaded with part bacterial DNA, continues to infect another bacterial cell.
  • This bacterial material may become recombined into another bacterium upon infection.

• Microbial Evasion of Phagocytosis

  • Bacteria often produce proteins or sugars that coat their cells and interfere with phagocytosis; these are called capsules.
  • Streptococcus pneumoniae produces several types of capsule which provide different levels of protection, and group A streptococci produce proteins such as M protein and fimbrial proteins to block engulfment.
  • Bacterial cells of Staphylococcus aureus: its large capsule protects the organism from attack by immunological defenses.

• Polysaccharide Biosynthesis

  • This "capsule" cloaks antigenic proteins on the bacterial surface that would otherwise provoke an immune response and thereby lead to the destruction of the bacteria.

• Glomerular Diseases

  • Bowman's capsule surround the glomerulus.
  • The blood is filtered through the capillaries of the glomerulus into the Bowman's capsule.
  • The Bowman's capsule empties the filtrate into a tubule that is also part of the nephron.
  • A glomerulus and its surrounding Bowman's capsule constitute a renal corpuscle, the basic filtration unit of the kidney.
  • Secondary causes are associated with certain infections (bacterial, viral, or parasitic pathogens), drugs, systemic disorders (SLE or vasculitis), or diabetes.

• Glycocalyx and Capsule

• Basic Structures of Prokaryotic Cells

  • Some bacteria have a capsule outside the cell wall.
  • For example, the capsule found in some species enables the organism to attach to surfaces, protects it from dehydration and attack by phagocytic cells, and increases its resistance to our immune responses.
  • It also varies between bacterial species.
  • The different bacterial responses to the staining procedure are ultimately due to cell wall structure.
  • Archaeal and bacterial phyla are shown; the evolutionary relationship between these phyla is still open to debate.

• Whooping Cough

  • Pertussis, more commonly known as whooping cough, is a bacterial infection of the upper respiratory system.
  • Pertussis is caused by the bacteria, Bordetella pertussis, a gram-negative, aerobic coccobacillus capsulate of the genus Bordetella .

• Bacterial Transformation

  • Transformation is one of three processes by which exogenous genetic material may be introduced into a bacterial cell; the other two being conjugation (transfer of genetic material between two bacterial cells in direct contact), and transduction (injection of foreign DNA by a bacteriophage virus into the host bacterium).
  • Bacterial transformation may be referred to as a stable genetic change, brought about by the uptake of naked DNA (DNA without associated cells or proteins).
  • About 1% of bacterial species are capable of naturally taking up DNA under laboratory conditions; more may be able to take it up in their natural environments.
  • Avery, et al. were first to demonstrate that "rough" colonies of S. pneumoniae could be transformed to "smooth" (capsule producing) colonies by addition of DNA extracts of the former to the latter, thus "transforming" them.
  • Illustration of bacterial transformation.

• Bone and Joint Disorders

  • Arthritis may arise from aging, damage to the articular cartilage, autoimmune diseases, bacterial or viral infections, or unknown (probably genetic) causes.
  • Other forms of arthritis are associated with various autoimmune diseases, bacterial infections of the joint, or unknown genetic causes.
  • In rheumatoid arthritis, the joint capsule and synovial membrane become inflamed.