Two-component systems

Examples of Two-component systems in the following topics:

• Two-Component Regulatory Systems

  • Two-component systems couple mechanism to allow organisms to sense and respond to changes in many different environmental conditions.
  • Two component signaling systems are widely occurring in prokaryotes whereas only a few two-component systems have been identified in eukaryotic organisms.
  • A variant of the two-component system is the phospho-relay system.
  • Signal transducing histidine kinases are the key elements in two-component signal transduction systems.
  • Describe the structure and function of a bacterial two-component regulatory system

• Complement Fixation

  • The complement fixation test consists of two components.
  • The first component is an indicator system that uses combination of sheep red blood cells, complement-fixing antibody such as immunoglobulin G produced against the sheep red blood cells and an exogenous source of complement usually guinea pig serum.
  • The second component is a known antigen and patient serum added to a suspension of sheep red blood cells in addition to complement.
  • These two components of the complement fixation method are tested in sequence.
  • If complement has not been bound by an antigen-antibody complex formed from the patient serum and known antigens, it is available to bind to the indicator system of sheep cells and anti-sheep antibody.

• Magnification and Resolution

  • Magnification is the enlargement of an image; resolution is the ability to tell two objects apart.
  • Resolution depends on the distance between two distinguishable radiating points.
  • A microscopic imaging system may have many individual components, including a lens and recording and display components.
  • Each of these contributes to the optical resolution of the system, as will the environment in which the imaging is performed.
  • Real optical systems are complex, and practical difficulties often increase the distance between distinguishable point sources.

• Type III and Type IV Secretion

  • Specifically, Type III and Type IV secretion systems are utilized by gram-negative pathogenic bacteria to transport proteins that function as pathogenic components.
  • The pathogenic bacteria which exhibit this capability contain a critical structural component, considered a protein appendage, that allows the injection of the protein into the host cell.
  • Another pathogen, Shigella, which utilizes type III secretion systems is able to successfully carry out its infection by evading the immune system.
  • The bacterial conjugation machinery allows transfer of genetic material to occur via direct cell-to-cell contact or by a bridge-like apparatus between the two cells.
  • The type IV secretion system utilizes a process similar to this.

• Cardiovascular and Lymphatic System Defenses

  • The circulatory system has a defence against microbial invaders in the form of the lymphatic system.
  • While the lymphatic system is part of the circulatory system, comprising a network of conduits called lymphatic vessels.
  • The lymph system is not a closed system.
  • The system also includes all the structures dedicated to the circulation and production of lymphocytes (the primary cellular component of lymph), which includes the spleen, thymus, bone marrow, and the lymphoid tissue associated with the digestive system.
  • There are two kinds of lymphocyte.

• Chemical Assays, Radioisotopic Methods, and Microelectrodes

  • Within the field of microbiology, there are specific tests or assays utilized to quantitatively and qualitatively measure microorganism components.
  • Chemical assays are utilized to identify and determine chemical components within a microorganism.
  • The two major mechanisms from which bacteria can obtain energy include oxidation of glucose and lactose fermentation.
  • Electrodes are characterized by a system of electrical conductors that are used to make contact with a non-metallic portion of a circuit.
  • The micro-electrodes have the capability to function as bio-sensors and detect specific biological components of microbes.

• Overview of the Immune System

  • The immune system is a system of biological structures and processes within an organism that protects against disease.
  • The immune system is a system of biological structures and processes within an organism that protects against disease.
  • Both innate and adaptive immunity depend on the ability of the immune system to distinguish between self and non-self molecules, where self molecules are those components of an organism's body that can be distinguished from foreign substances by the immune system.
  • Immunity involves both specific and non-specific components .
  • Adaptive immunity is often sub-divided into two major types depending on how the immunity was introduced.

• Mapping Protein-Protein Interactions

  • In living organisms most of the biological functions are mediated by complex multi-component protein machineries and network activities.
  • The most widely employed tools are the yeast two-hybrid system and affinity purification coupled to mass spectrometry.
  • Datasets obtained from such tools are further analyzed using computational methods to draw a map of protein connectivity and achieve system level understanding of a microorganism.
  • The yeast two-hybrid screening system is an effective and quick tool for the in vivo study of protein–protein interaction both in prokaryotes and eukaryotes.
  • If the two proteins do interact the bait recruits the prey to a specific cellular location where it can stimulate a detectable output (e.g., gene activation).

• Shuttle Vectors and Expression Vectors

  • A shuttle vector is a vector that can propagate in two different host species, hence, inserted DNA can be tested or manipulated in two different cell types.
  • The main advantage of these vectors is that they can be manipulated in E. coli and then used in a system which is more difficult or slower to use.
  • One of the most common types of shuttle vectors is the yeast shuttle vector that contains components allowing for the replication and selection in both E. coli cells and yeast cells.
  • The E. coli component of a yeast shuttle vector includes an origin of replication and a selectable marker, such as an antibiotic resistance like beta lactamase.
  • The yeast component of a yeast shuttle vector includes an autonomously replicating sequence (ARS), a yeast centromere (CEN), and a yeast selectable marker.

• Iron-Binding Proteins

  • Iron binding proteins of the innate immune system include lactoferrin and transferrins.
  • Lactoferrin is one of the components of the immune system of the body.
  • Transferrin has a molecular weight of around 80 KDa and contains two specific high-affinity Fe(III) binding sites.