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Pathogens – Bacteria & Pathogens – Bacteria & VirusesViruses
Protists & Fungi TooProtists & Fungi Too
A Pathogen is…A Pathogen is…
Pathogen = Any disease causing Pathogen = Any disease causing agent.agent.
–Examples:Examples: Bacteria: Streptococcus, StaphylococcusBacteria: Streptococcus, Staphylococcus Virus: HIV, Influenza (Swine Flu), The Virus: HIV, Influenza (Swine Flu), The
common coldcommon cold Protist: Plasmodium (malaria)Protist: Plasmodium (malaria) Fungi: Ringworm, Athletes FootFungi: Ringworm, Athletes Foot
Viruses – Properties of LifeViruses – Properties of Life
Properties of LifeProperties of LifeCellular organizationCellular organization
ReproductionReproduction YesYesMetabolismMetabolism
HomeostasisHomeostasis
AdaptionAdaption YesYesResponsivenessResponsiveness YesYesGrowth and DevelopmentGrowth and Development NO
NO
NO
NO
Virus SizeVirus Size
Viruses are SOOO Small!Viruses are SOOO Small!
Too small to see with a Too small to see with a regular light regular light microscopemicroscope
Must use an Must use an electronelectron microscope to be microscope to be seen.seen.
Parts of a VirusParts of a Virus CapsidCapsid= “head”…protein that encloses = “head”…protein that encloses
viral genomeviral genome GenomeGenome= double stranded DNA OR = double stranded DNA OR
single stranded DNA or RNAsingle stranded DNA or RNA
Viral Body PlansViral Body Plans
Genetic material is DNA or Genetic material is DNA or RNARNA
Coat is protein Coat is protein
Complex virus(bacteriophage)
Polyhedral virus
Rod-shaped virus
head
sheath
tail fiber
Viruses are Obligate Intracellular Viruses are Obligate Intracellular ParasitesParasites
Obligate like an Obligate like an obligationobligation – can only – can only replicate inside other cellsreplicate inside other cells
Must live within a Must live within a specificspecific host cell – host cell – exampleexample: cats don’t get chicken pox: cats don’t get chicken pox
Use the host cell for replication, metabolism, Use the host cell for replication, metabolism, etc.etc.
Viruses cause diseaseViruses cause disease
InfluenzaInfluenza– Infects the upper respiratory Infects the upper respiratory
tracttract
Can also cause cancerCan also cause cancer– Hepatitis B Hepatitis B liver cancer liver cancer– Epstein-Barr virus Epstein-Barr virus Burkitt’s Burkitt’s
lymphomalymphoma– Human Papilloma Virus Human Papilloma Virus
cervical cancercervical cancer
HIV, the AIDS virusHIV, the AIDS virus
Glycoproteins on HIV envelope Glycoproteins on HIV envelope recognize surface proteins of human recognize surface proteins of human white blood cellswhite blood cells
RNA virusRNA virus Includes the reverse transcriptase Includes the reverse transcriptase
enzymeenzyme
Defenses against virusesDefenses against viruses
Skin and mucus membranesSkin and mucus membranes Inflammation (redness, swelling, Inflammation (redness, swelling,
warmth and pain)warmth and pain) White blood cellsWhite blood cells Antibodies- specific proteins that Antibodies- specific proteins that
target a specific virustarget a specific virus Interferons- enzymes that prevent Interferons- enzymes that prevent
the virus from replicatingthe virus from replicating
T4 Bacteriophages on Escherichia coli) bacteria. T4 bacteriophages are parasites of E. coli, a bacteria common in the human gut. The virus attaches itself to the host bacteria cell wall by its tail fibers. The sheath then contracts, injecting the contents of the head (DNA) into the host. The viral DNA makes the bacteria manufacture more copies of the virus. TEM X40,000.
Credit: © Dr. George Chapman/Visuals Unlimited
T4 Bacteriophages on Escherichia coli bacteria. T4 bacteriophages are parasites of E. coli, a bacteria common in the human gut. The virus attaches itself to the host bacteria cell wall by its tail fibers. The sheath then contracts, injecting the contents of the head (DNA) into the host. The viral DNA makes the bacteria manufacture more copies of the virus. TEM X60,000.
Credit: © Dr. George Chapman/Visuals Unlimited
Bacteria - ProkaryotesBacteria - Prokaryotes
Eubacteria = True Bacteria. Eubacteria = True Bacteria. – Cell wall contains the carbohydrate Cell wall contains the carbohydrate
peptidoglycanpeptidoglycan
Archaeabacteria = Ancient Bacteria. Archaeabacteria = Ancient Bacteria. – NO peptidoglycan in cell walls. NO peptidoglycan in cell walls. – MORE similar to Eukaryotes!!! (US)MORE similar to Eukaryotes!!! (US)– Live in harsh environmentsLive in harsh environments
Bacteria are very small
This is a pore in human skin and the yellow spheres are bacteria
Bacteria are very small compar-ed to cells with nuclei
Bacteria compared to a white blood cell that is going to eat it
Bacteria
Clean skin has about 20 million bacteria per square inch
StructureStructure
No nucleusNo nucleus No membrane No membrane
bound organellesbound organelles DNA is circular DNA is circular
PlasmidsPlasmids
Bacteria ShapesBacteria ShapesPage 546
E. coli is a gram-negative, facultatively anaerobic, rod prokaryote undergoing conjugation. One strain has fimbriae. E. coli can cause urinary tract infections, traveler's diarrhea, nosocomial infections, and a variety of skin and wound infections such as scalded skin syndrome, scarlet fever, erysipelas and impetigo. TEM.
Credit: © Dr. Dennis Kunkel/Visuals Unlimited
284564
Bacterial ReproductionBacterial Reproduction
Bacterial reproductionBacterial reproduction
Cellular organism copies it’s genetic information then splits into two identical daughter cells
ConjugationConjugation
http://images.google.com/imgres?imgurl=http://content.answers.com/main/content/wp/en/thumb/0/02/350px-BacterConjugation.png&imgrefurl=http://www.answers.com/topic/bacterial-conjugation&h=410&w=350&sz=75&hl=en&start=1&tbnid=JeAQL49IMC-LqM:&tbnh=125&tbnw=107&prev=/images%3Fq%3Dconjugation%26gbv%3D2%26hl%3Den
Bacterial reproductionBacterial reproduction
http://images.google.com/imgres?imgurl=http://www.drnatura.com/img/good_bad_bacteria.jpg&imgrefurl=http://www.drnatura.com/flora_protect.php&h=248&w=389&sz=44&hl=en&start=3&tbnid=oCRN34FnS1MmzM:&tbnh=78&tbnw=123&prev=/images%3Fq%3Dgood%2Bbacteria%2Bin%2Bcolon%26gbv%3D2%26hl%3Den
Good Bacteria
Good causing bacteriaGood causing bacteria E. Coli in stomach aids digestionE. Coli in stomach aids digestion Benefit soilBenefit soil NitrificationNitrification DecompositionDecomposition Make acetone or butanolMake acetone or butanol To produce insulin, other chemicalsTo produce insulin, other chemicals Clean oil spillsClean oil spills To clean oreTo clean ore Yogurt, cheese, olives, vinegar, sourdoughYogurt, cheese, olives, vinegar, sourdough
Disease causing bacteriaDisease causing bacteria
Way 1: metabolize their host (destroy host Way 1: metabolize their host (destroy host cells)cells)
Way 2: secrete poison as waste productWay 2: secrete poison as waste product
TUBERCULOSISTUBERCULOSIS
STREP THROATSTREP THROAT
LYME DISEASELYME DISEASE
This bacteria can causes toxic shock syndrome (tampon use) and can also cause impetigo and pyoderma and is common in infant day care centers. SEM.
Credit: © Dr. Gary Gaugler/Visuals Unlimited
197376
Staphylococcus aureus
ArchaeabacteriaArchaeabacteria
Pathogens & EvolutionPathogens & Evolution
Pathogens, like bacteria are living organisms our Pathogens, like bacteria are living organisms our bodies and antibiotics kill like streptococcus. bodies and antibiotics kill like streptococcus. Penicillin when first created was considered the Penicillin when first created was considered the miracle drug as it killed so many bacterial miracle drug as it killed so many bacterial infections. However these bacteria are living infections. However these bacteria are living organisms and wanted to live so they organisms and wanted to live so they evolved/adapted to the drug so that penicillin evolved/adapted to the drug so that penicillin won’t hurt them. Thus doctors must create new won’t hurt them. Thus doctors must create new antibiotics once a pathogen adapts to an old antibiotics once a pathogen adapts to an old antibiotic.antibiotic.
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