AnnouncementsBacteria and Archaea IIBacteriaInformation Flow and StorageLateral Gene TransferArchaeaWhat is causing a decrease in microbial species diversity?23_BIO130_0401144/01/2014Bio 130 TR 12:40-1:55p AnnouncementsExam 2 will be returned by next weekBig Idea writing assignment due April 15th Bacteria and Archaea IIReminder: All living organisms today all have a commonancestor and have been evolving the same amount of time. Noliving species is more “primitive” than another. Objectives:- Describe ecological interactions- Explain horizontal (lateral) gene transferBacteriaThe diversity of bacteria’s’ feeding strategies, allows them to occupy diverse and “stressful” environments. The evolution of cyanobacteria had a major influence on evolution. Cyanobacteria were the first to photosynthesize and give off oxygen. This allowed organisms to evolve aerobic respiration which provides more ATP. Bacteria are the most abundant organisms on the planet, and include extremophiles. They fix nitrogen, decompose detritus and cause disease. Only a small amount are pathogenic, but they form many mutualisms. Many helpful microbes live on and in humans. Microbial diversity varies between individuals.NPR: Exploring the Invisible Universe that Lives on Us1. Why is our microbiome important?>1000 species. There are 10 times more microbial cells than human cells. They can defend against infections and create their own antibiotics. They regulate metabolism, assist our immune system and signal cells. The beneficial flora compete with harmful bacteria for nutrients. They help train your immune system. They use some of the nutrients we digest to break down food our bodies cannot. There is strong selective pressure on the species to be able to digest food efficiently.2. What decreases their diversity?C-sections, lack of breastfeeding, antibiotics and sterilization.3. How can we restore microbiome diversity?Eating probiotics, prebiotics and breastfeeding, less antibiotics and c-sectionsInformation Flow and StorageThe DNA in most bacteria is circular. Plasmids are additional DNA independent of the chromosome. Theirreproduction is asexual reproduction through binary fission. Daughter cells are identical to parent cells, the population is unable to adapt because there is no genetic variation. Variation is added through mutations and lateral gene transfer.Lateral Gene TransferUnrelated individuals from different species transfer genetic material. It is more common than mutation. It makes it hard to determine accurate phylogenies. The main finding of the Hehemann et al study summarized in the Sonnenburg 2010 article was that some peoples’ bacteria acquired genes from marine species in their food that allowed them to digest seaweed. Cleanliness means we are consuming less bacteria and the diversity of are gut microbes is decreasing.ArchaeaArchaea are extremely abundant, many are extremophiles and can occupy stressful environments, but mesophile examples can be found in normal habitats. There are examples of Archaea that live in the gut alongside bacteria. Their DNA is circular with histones that condense the DNA. They also have plasmids, lateral gene transfer and asexual reproduction. Their DNA transcription is more similar to eukaryotes. What is causing a decrease in microbial species diversity?Overuse of antibiotics – selecting for antibiotic resistanceHand soap, dish soap, and hand gels are all antibacterialNormal soap just surrounds insoluble particles to be able to wash them awayAntimicrobial soap also kills the