PEPTIDES (Syllabus: GS Paper 3 - Sci & Tech

Context: The immune systems of fruit flies develop certain genes that can combat common bacteria found in food, a new study has found.

Key Points

• Bacteria such as acetobacter found in fruits can harm flies once they exit the gut and reach the bloodstream. 
• However, various fly species have developed a specific peptide (strings of compounds that combine to form proteins) that can fight acetobacter.
• The findings are critical as fruit flies’ evolutionary process might help explain human susceptibility to certain diseases.
• The bacteria in their food and environment mould the immune systems of fruit flies. 
• These flies have developed two peptides to defend a single bacterial species that affects them.
• Some of these peptides are common in certain species.
• Various fly species have developed a particular peptide (diptericin B) to control acetobacter.
• Glial cells and neurons in the fly brain communicate, dampening olfaction and shielding the animals from consuming the pathogen again after an intestinal bacterial infection.

Peptides 

• Peptides are short chains of amino acids linked tide bonds.
• A polypeptide is a longer, continuous, unbranched peptide chain.
• Polypeptides which have a molecular mass of 10,000 Da or more are called proteins.
• Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
• Peptides can perform interactions with proteins and other macromolecules. 
• They are responsible for several important function in human cells, such as cell signaling and act as immune modulators