View source for Chapter !6 - Genomes of Prokaryotes Code : KSI0015

<p style="text-align:center"><span style="font-size:36px">&lt;Index of Genomes of Prokaryotes&gt;</span></p>

<p>Prokaryotes have several claims on our interest.&nbsp;</p>

<p>1.They have cause infectious diseases. Some diseases, such as tuberculosis, are major public health problems. It&#39;s a challenge to control these diseases in the face of the development of antibiotic resistance.&nbsp;</p>

<p>2.Molecular biologists study prokaryotes as examples of relatively simple cells, to understand fundamental principles of metabolism, genetics, and development</p>

<p>3.Prokaryotes represent the earliest forms of life, from which all others are derived.&nbsp;</p>

<p>4.Prokaryotes are imporatnt mediatos of ecolofical processes and geological cycles. Indeed, geological and biological phenomena are linked in an intimate marriage, which has seen its turbulent episodes.&nbsp;</p>

<p>&nbsp;</p>

<p>Major types of prokaryotes.&nbsp;</p>

<p>1. Some genes in archaea but non in bacteria contain introns</p>

<p>2. They are systematic differences in tRNA sequences between archaea and bacteria.&nbsp;</p>

<p>3. Enzymes involved in DNA replication such as DNA polymerase and some of the tRNa synthetases involven in protein synthesis, differ between archaea and bacteria.&nbsp;</p>

<p>4. Archaea but not bacteria contain DNA-associated proteins resembling histones.&nbsp;</p>

<p>5. Membranes &nbsp;of all cells contain phospholipids. Compounds combining a glycerol molecule with long chain organic molecules.</p>

<p>6. Cell wall structures : Bacterial but not archaeal cell walls contain peptididoglycan, a combination of sugar derivatives and peptides.&nbsp;</p>

<p>7. Archaea and bacteria differ in their complement of metabolic pathways.</p>

<p>&nbsp;</p>

<p><span style="color:#0000CD"><strong><span style="font-size:16px">Evolution and phylogenetic relationships in prokaryotes</span></strong></span></p>

<p><span style="font-size:16px">-Major types of prokaryotes</span></p>

<p><span style="font-size:16px">-Do we know the root of the tree of life?</span></p>

<p>&nbsp;</p>

<p>&nbsp;</p>

<p><span style="color:#0000CD"><strong><span style="font-size:16px">Archaea&nbsp;</span></strong></span></p>

<p>EX &gt; Methanogens as sources of greenhouse gas emission. : The case of New Zealand.&nbsp;</p>

<p>&nbsp;</p>

<p><span style="font-size:16px">-The genome of Methanococcus jannaschii</span></p>

<p>&gt; Hydrothermal vents are underwater volcanoes emitting hot lava and gases through cracks in the ocean floor&nbsp;</p>

<p><span style="font-size:16px">-Life at extreme temperatures</span></p>

<p>EX &gt; Effet of beta - branched sidechains on protein stability.</p>

<p>&nbsp;</p>

<p><span style="font-size:16px">-Comparative genomics of hyperthermophilic archaea</span></p>

<p><span style="font-size:16px">-Thermococcus kodakarensis and pyrococci</span></p>

<p>&nbsp;</p>

<p><span style="font-size:20px"><strong><span style="color:#0000CD">Bacteria&nbsp;</span></strong></span></p>

<p>Genomics of pathogenic bacteria : virulence factors&nbsp;</p>

<p>Horizontal gene transfer is a common theme in development of virulence and antibiotic resistance.&nbsp;</p>

<p>Genomics and the development of vaccines.&nbsp;</p>

<p>The future of antibiotic development</p>

<p>Our descendants may well look back at the second half of the 20th century as a narrow window during which bacterial infections could be controlled, and before and after which they could not.</p>

<p>&nbsp;</p>

<p><span style="color:#0000CD"><strong><span style="font-size:16px">Metagenomics : The collection of genomes in a coherent environmental sample</span></strong></span></p>

<p><span style="font-size:16px">-Marine cyanobacteria - an in-depth study</span></p>

<p>-Clarify evolutionary relationships.&nbsp;</p>

<p>-Use high-throughput sequencinng methods to study a cross-section of the life in a natural sample.&nbsp;</p>

<p>-Study the majority of strains that are difficult to grow in culture.&nbsp;</p>

<p>-Appreciate the relationships and interactions among different species that share an ecosystem.&nbsp;</p>

<p>-A milliitre of ocean water may contain 100-200 species. A gram of soil may contain 400.&nbsp;</p>

<p>&nbsp;</p>

<p>&gt; How are different procholorococcus strains adapted to differences in ambient light itensities and spectral distributions?&nbsp;</p>

<p>Protection against photochemical damage</p>

<p>-Utilization of nitrogen sources.&nbsp;</p>

<p>-Protection aginst predators and viruses.&nbsp;</p>