amino-acid starvation

Examples of amino-acid starvation in the following topics:

• The Stringent Response

  • The stringent response is a stress response that occurs in bacteria in reaction to amino-acid starvation or other stress conditions.
  • The stringent response, also called stringent control, is a stress response that occurs in bacteria and plant chloroplasts in reaction to amino-acid starvation , fatty acid limitation, iron limitation, heat shock, and other stress conditions.
  • This in turn causes the cell to divert resources away from growth and division and toward amino acid synthesis in order to promote survival until nutrient conditions improve.
  • The generic structure of an alpha amino acid in its un-ionized form.

• Activation of Starvation by Survival Genes

  • Stringent Response, also called stringent control, is a stress response that occurs in bacteria and plant chloroplasts in reaction to amino-acid starvation, fatty acid limitation, iron limitation, heat shock, and other stress conditions.
  • This in turn causes the cell to divert resources away from growth and division and toward amino acid synthesis in order to promote survival until nutrient conditions improve.

• Connecting Proteins to Glucose Metabolism

  • However, if there are excess amino acids, or if the body is in a state of starvation, some amino acids will be shunted into the pathways of glucose catabolism.
  • Each amino acid must have its amino group removed (deamination) prior to the carbon chain's entry into these pathways.
  • When the amino group is removed from an amino acid, it is converted into ammonia through the urea cycle.
  • The remaining atoms of the amino acid result in a keto acid: a carbon chain with one ketone and one carboxylic acid group.
  • Several amino acids can enter glucose catabolism at multiple locations.

• Proteins: Sources, Uses in the Body, and Dietary Requirements

  • Most microorganisms and plants can biosynthesize all 20 standard amino acids , while animals (including humans) must obtain some of the amino acids from the diet.
  • The amino acids that an organism cannot synthesize on its own are referred to as essential amino acids.
  • Key enzymes that synthesize certain amino acids are not present in animals.
  • In animals, amino acids are obtained through the consumption of foods containing protein .
  • Amino acids are also an important dietary source of nitrogen.

• Amino Acids

  • An amino acid contains an amino group, a carboxyl group, and an R group, and it combines with other amino acids to form polypeptide chains.
  • The name "amino acid" is derived from the amino group and carboxyl-acid-group in their basic structure.
  • Each amino acid is attached to another amino acid by a covalent bond, known as a peptide bond.
  • When two amino acids are covalently attached by a peptide bond, the carboxyl group of one amino acid and the amino group of the incoming amino acid combine and release a molecule of water.
  • The carboxyl group of one amino acid is linked to the amino group of the incoming amino acid.

• Starvation-Induced Fruiting Bodies

  • Starvation-induced fruiting bodies can aggregate up to 500 micrometres long and contain approximately 100,000 bacterial cells.
  • When starved of amino acids, myxobacteria, or slime bacteria, detect surrounding cells in a process known as quorum sensing.

• The Incorporation of Nonstandard Amino Acids

  • Aside from the 22 standard amino acids, there are many other amino acids that are called non-proteinogenic or non-standard.
  • Also, most nascent polypeptides start with the amino acid methionine because the "start" codon on mRNA also codes for this amino acid.
  • Aside from the 22 standard amino acids, there are many other amino acids that are called non-proteinogenic or non-standard .
  • Some nonstandard amino acids are not found in proteins.
  • Nonstandard amino acids often occur as intermediates in the metabolic pathways for standard amino acids.

• The Endocrine System and Hunger

  • Blood levels of glucose, amino acids, and fatty acids provide a constant flow of information to the brain that may be linked to regulating hunger and energy intake.
  • They inhibit hunger by raising blood glucose levels, elevating blood levels of amino acids, and affecting blood concentrations of fatty acids.
  • Starvation is a severe deficiency in caloric energy, nutrient, and vitamin intake.
  • Prolonged starvation can cause permanent organ damage and, untreated, leads to death.
  • Vitamin deficiency, diarrhea, skin rashes, edema, and heart failure are also common results of starvation.

• Nutrition and Health

  • These molecules are broken down into essential amino acids and fatty acids and used as fuel for cellular functions.
  • The Basics of Nutrition: Macronutrients, Amino and Fatty Acids, and Micronutrients
  • Amino acids are organic compounds primarily composed of oxygen, hydrogen, nitrogen, and carbon.
  • Proteins are made up of chains of amino acids connected by peptide bonds; they form hormones, enzymes, and antibodies within the human body.
  • There are twenty standard amino acids, nine of which are essential and must be obtained from food.

• Amino Acid Synthesis

  • These polymers are linear and unbranched, with each amino acid within the chain attached to two neighboring amino acids.
  • Twenty-two amino acids are naturally incorporated into polypeptides and are called proteinogenic or natural amino acids.
  • Amino acid synthesis depends on the formation of the appropriate alpha-keto acid, which is then transaminated to form an amino acid.
  • Aside from the 22 standard amino acids, there are many other amino acids that are called non-proteinogenic or non-standard.
  • Nonstandard amino acids often occur as intermediates in the metabolic pathways for standard amino acids — for example, ornithine and citrulline occur in the urea cycle, part of amino acid catabolism.