secondary messenger

Examples of secondary messenger in the following topics:

• Direct Gene Activation and the Second-Messenger System

  • This signal is called the secondary messenger.
  • The secondary messenger may then activate a secondary effector, whose effects depend on the particular secondary messenger system.
  • The effector stimulates a second messenger synthesis. 4.
  • The second messenger activates an intercellular process.
  • Distinguish between the hormone mechanisms of direct gene activation and the second-messenger system

• Ionotropic and Metabotropic Receptors

  • Ionotropic receptors are a group of transmembrane ion channels that open or close in response to the binding of a chemical messenger (ligand) such as a neurotransmitter.The binding site of endogenous ligands on LGICs protein complexes are normally located on a different portion of the protein (an allosteric binding site) than the location of the ion conduction pore.The ion channel is regulated by a ligand and is usually very selective to one or more ions such as Na+, K+, Ca2+, or Cl-.
  • Metabotropic receptors are a subtype of membrane receptors that do not form an ion channel pore but use signal transduction mechanisms, often G proteins, to activate a series of intracellular events using second messenger chemicals.
  • When the neurotransmitter binds to the receptor, there is an activation via the G-protein that later activates the  secondary messengers.

• Hormone Receptors

  • Following an interaction with the hormones, a cascade of secondary effects within the cytoplasm of the cell is triggered, often involving the addition or removal of phosphate groups to cytoplasmic proteins, changes in ion channel permeability, or an increase in the concentrations of intracellular molecules that may act as secondary messengers, such as cyclic AMP.

• Overview of the Endocrine System

  • The endocrine system is a system of ductless glands that secrete hormones—chemical messengers that are carried for long distances.
  • The major endocrine glands include the pituitary, pineal, ovaries, testes, thyroid, hypothalamus and adrenal glands, additionally other tissues such as the kidney and liver also display secondary adrenal functions.

• Viroids

  • The replication mechanism involves RNA polymerase II, an enzyme normally associated with synthesis of messenger RNA from DNA, which instead catalyzes "rolling circle" synthesis of new RNA using the viroid's RNA as template.
  • This reflects the fact that any siRNAs produced would have less complementary base pairing with target messenger RNA.
  • The viroid siRNAs actually contain sequences capable of complementary base pairing with the plant's own messenger RNAs and induction of degradation or inhibition of translation is what causes the classic viroid symptoms.
  • Their secondary structure is key to their biological activity.
  • black - secondary structure of the viroid red - GAAAC sequence common to all viroids yellow - central conservative sequence blue - nucleotide numbers

• Nonribosomal Peptide Antibiotics

  • Nonribosomal peptides (NRP) are a class of peptide secondary metabolites which can function as antibiotics.
  • Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi.
  • Nonribosomal peptides are synthesized by nonribosomal peptide synthetases, which, unlike the ribosomes, are independent of messenger RNA.

• Primary and Secondary Research

• Secondary Groups

  • Some secondary groups may last for many years, though most are short term.
  • Secondary relationships involve weak emotional ties and little personal knowledge of one another.
  • The distinction between primary and secondary groups was originally proposed by Charles Cooley.
  • A secondary group is one you have chosen to be a part of.
  • Primary groups can form within secondary groups as relationships become more personal and close.

• Antisense Agents

  • Antisense agents are short oligonucleotides that bind to target messenger RNA and inhibit protein synthesis.
  • Antisense agents are synthetic, single-stranded short sequences of DNA bases designed to hybridize to specific sequences of messenger RNA (mRNA) forming a duplex .
  • When this agent binds to the pathogen DNA or messenger RNA, the biosynthesis of target proteins is disrupted.

• Additional Resources

  • From Marbles to Instant Messenger™: Implications of Piaget's Ideas About Peer Learning.
  • Jean Piaget Archives - Web site for the University of Geneva's collection of Piaget's writings as well as secondary literature "inspired by the School of Geneva in the field of developmental psychology.