Bacteria v Virus

Structure of a Bacterial Cell Cell Wall -maintains cell structure -composed of peptidoglycan, a polymer of sugars and amino acids Plasma Membrane phospholipid bilayer Nucleoid The region DNA is found in prokaryotes DNA A single double-stranded circular chromosome NO histone proteins Plasmid small circular chromosome may carry an antibiotic resistance gene Flagella -tail-like structure used for locomotion http://en.wikipedia.org/wiki/Image:Average_prokaryote_cell-_en.svg

Features of an Infectious Bacteria capsule: surrounds bacterial cell wall; protects bacteria from phagocytosis pili: allows bacteria to attach to and invade other cells despite mucous and cell-turnover enzymes: break down matrix between cells allowing bacteria to spread throughout tissues

Bacteria create Toxins exotoxins: cause lysis (breakage) of specific host cells enterotoxins: cause secretion of fluid into the small intestine leading to vomiting and diarrhea endotoxins: cell-bound lipopolysaccharides; causes fever and inflammation http://en.wikipedia.org/wiki/Image:Average_prokaryote_cell-_en.svg

Bacterial Transcription and Translation is quicker then eukaryotes Fast Reproduction Bacterial Transcription and Translation is quicker then eukaryotes Reproduction occurs independent of host cell Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

Bacterial Illness: Strep Throat Infectious agent: Streptococcus pyogenes spherical bacteria usually found in pairs or chains most sore throats are actually caused by viruses and are NOT considered strep throat (~15-35% are strep throat) symptoms: sudden, severe sore throat, fever over 101°F, swollen tonsils and lymph nodes, white or yellow spots on the back of a bright red throat transmission usually by air-born bacteria incubation period prior to symptoms 2-5 days diagnosed with a throat culture and detection of strep-specific molecules treated with antibiotics, usually penicillin for 10 days

Antibiotic Treatment of Bacterial Infections antibiotics kill bacteria or prevent bacteria from dividing antibiotics are produced naturally by bacteria and fungi antibiotics are mass produced by growing huge cultures of the source microbe Why might microbes produce antibiotics in nature? Staphyloccocus aureus antibiotic http://en.wikipedia.org/wiki/Image:Staphylococcus_aureus_%28AB_Test%29.jpg Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

Antibiotics: Mechanisms of Action Inhibition of Bacterial Protein Synthesis - some antibiotics bind to the large or small subunit of the bacterial ribosome Examples: neomycin, streptomycin, azithromycin, erythromycin, tetracycline Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College. http://en.wikipedia.org/wiki/Image:Average_prokaryote_cell-_en.svg

Antibiotics: Mechanisms of Action Inhibition of Cell Wall Synthesis -some antibiotics prevent peptidoglycan formation Examples: vancomycin, amoxicillin, ampicillin, penicillin Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College. http://en.wikipedia.org/wiki/Image:Average_prokaryote_cell-_en.svg

Animation of Antimicrobial Resistance

single stranded OR double stranded RNA or DNA Properties of Viruses Basic Structure single stranded OR double stranded RNA or DNA protein shell capsid some have a lipid bilayer with embedded proteins Host Cell Influenza Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College. http://microbewiki.kenyon.edu/index.php/Image:8430_lores.jpg

Virus Life Cycle and reproduction virus attaches to host cell Properties of Viruses Virus Life Cycle and reproduction virus attaches to host cell virus enters cell via endocytosis capsid degraded host transcribes viral DNA host ribosomes translate viral RNA new viruses assemble Host Cell Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

Viral Illness: The Common Cold http://en.wikipedia.org/wiki/Image:Rhinovirus.PNG symptoms: sore throat, runny nose, nasal congestion, cough prevalance: 3 colds/ person/ year incubation period 2-5 days no cure for the common cold (or the flu) Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

Rotavirus is a virus that causes gastroenteritis (inflammation of the stomach and intestines).

Why don’t antibiotics work for viral infections? Bacterial vs. Viral Infections Watch Video Why don’t antibiotics work for viral infections? MicrobeLibrary.org; © Jean-Yves Sgro, University of Wisconsin http://www.microbelibrary.org/microbelibrary/files/ccImages/Articleimages/simonson/Images/Streptococcus%20sobrinus%20fig1.jpg Polio Virus Streptococcus Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

Bacterial Infections Viral Infections strep throat gastroenteritis cholera tuberculosis food poisoning botulism gangrene necrotizing fasciitis boils, abscesses pneumonia acne meningitis ulcers the flu colds AIDS hepatitis chicken pox gastroenteritis measles mumps E. Bola pneumonia West Nile cervical cancer Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.