Summary

This document discusses cell communication, particularly quorum sensing and signal transduction in various organisms, including bacteria. It highlights the importance of communication in engineered systems and examples of animals with exceptional senses of smell. 

Full Transcript

§ Elephant: smell water up to 20 km away § Bear: smell a carcass up to 30 km away § Great white shark: smell blood in the water up to 5 km away Swim towards the source @50 kmph https://www.balisafarimarinepark.com/animals-with-an-exceptional-sense-of-smell/ § Quorum sensing § Signal tra...

§ Elephant: smell water up to 20 km away § Bear: smell a carcass up to 30 km away § Great white shark: smell blood in the water up to 5 km away Swim towards the source @50 kmph https://www.balisafarimarinepark.com/animals-with-an-exceptional-sense-of-smell/ § Quorum sensing § Signal transduction – an overview § G proteins www.sc.iitb.ac.in Matsya ?? Rakshak Pratham SeDriCa IGV Is communication important in all these engineered systems? Figure titles are hyperlinked to respective web pages. Yeast (shown in false color in an electron micrograph) is from https://www.sciencenews.org/article/yeast-life-span-calorie-restriction-may-be-wash 0.5 mm favorable Fruiting conditions bodies (spores) 2.5 mm Individual rod shaped cells Nutrient scarcity Cells collectively 0.5 mm 0.5 mm Starving cells form fruiting body send out a chemical signal Aggregation in progress Spore-forming structure (fruiting body) Soil-dwelling bacteria Myxococcus xanthus Figure 11.3 in Campbell Biology by Reece et al., (10th edition) Quorum (ko-rum): minimum number of members that must be present in a meeting to make the proceedings valid § Bacteria are capable of quorum sensing! Regulate gene expression depending upon cell-population density § Quorum sensing is widespread among prokaryotes and eukaryotes § The general mechanism is evolutionarily conserved and serves a variety of physiological purposes § Quorum-sensing is extensively studied in the bacteria Vibrio fischeri § Luminescence: emission of light by a substance that is not heated Lux: unit of luminescence § Genes involved in bioluminescence are named as lux genes § Gene names: italics + all letters in lower case § Encoded proteins: normal font + first letter in upper case § Plating seawater samples revealed the presence of bioluminescent bacteria Luminescence: emission of light by a substance that is not heated § Abundance in sea water:

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