Microbiology week 2 sunday

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Microbiology week 2 sunday
2012-12-07 17:59:19
week sunday

Micro week 2 sunday
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  1. various microbial eukaryotes
    • i. Fungi
    • ii. Protozoa 
    • iii. Helminths
  2. types of non-living infectious agents (all are different)
    • i.  viruses
    • ii.  viriods 
    • iii. prions
  3. Fungal General Characteristics
    • eukaryotic cells
    • (all fungi )reproduce sexualy and nonsexually) 
    • nonmotile 
    • heterotrophic (use organic compounds a carbon source; they can’t make their own sugars(FOOD); no photosynthesis)
  4. Fungi facultative anaerobes example
  5. Fungi saprophytes - obtain nutrients by
    decomposing dead & decaying matter important in ecosystems as decomposers 
  6. Fungi structure
    • hyphae can be coenocytic NO SEPERATION NO CROSS WALL (undivided network of branching tubes) or have SEPTA (cross walls).
  7. Fungus have cell wal;s composed of
    • •cellulose, chitin (contains nitrogen - also found in the
    • exoskeletons of insects, crayfish, etc.), or a combination of the two.
  8. Fungi reproduction
    • Asexual
    • Sexual
  9. Fungi asexual reproduction 
    • Occurs by elongation of hyphae, budding, or asexual spore production
    • Only contain one genome
    • Budding is one cell copying its genome and seppararing (like yeast)
  10. (Fungi) Asexual Spores are products of a type of cell division called 
    mitosis (one cell divides to form 2 daughter cells that are identical to one another and to the original parent cell).
  11. Types of asexual spores
    • sporangiospores
    • conidiospores
  12. Fungi Sexual Reproduction Occurs by 
    producing sexual spores, which form following sexual fusion of gametes (similar to sperm & eggs)
  13. Types of sexual reproducing fungi
    • zygospore
    • ascospores
    • basidiospores
  14. Underground one filament fungi are known as
  15. Duramycota fungi 
    • Imperfect fungi, group not known much about only that they reproduce asexual and are temporary grouping
    • untill more info is known
  16.  Yeasts vs. Molds
    • •Yeast are nonfilamentous and unicellular
    • •Molds are filamentous and multicellular
  17. Fungi key points
    • •Fungi are eukaryotes
    • •Fungi are heterotrophs 
    • •Can reproduce via asexual and/or sexual reproduction
    • •Can cause human diseases
    • •Many different types of fungi
  18. Mycoses
    • •Humans usually acquire fungal disease from nature; they are not highly contagious.
    • •Fungi are a leading cause of nosocomial infections (hospital aquire infections)
    • Fungal infections are a major problem in immune suppressed people. 
    • Fungal infections are often mistaken for bacterial infections, with fatal consequences.
  19. Mycoses fungi
    • •Superficial
    • •Cutaneous 
    • •Subcutaneous  
    • •Systemic (most dangerous) 
    • •Opportunistic (most dangerous)
  20. Superficial mycoses infection of outerlayer of skin
    • Pityriasis versicolor--pigmented lesions on torso
    • Tinea nigra--gray to black macular lesions often on palms
    • Black piedra--dark gritty deposits on hair
    • White piedra--soft whitish granules along hair shaft
    • All are diagnosed by microscopy and are easily treated by topical preparations
  21. Three genera of dermatophytes:
    • Microsporum
    • Trichophyton 
    • Epidermophyton 
    • -cause infections of skin and its appendages
  22. Systemic fungal disease is most often associated with four organisms
    • 1.Coccidioides immitis
    • 2.  Histoplasma capsulatum 
    • 3.Blastomyces dermatitidis 
    • 4.Paracoccidioides brasiliensis  (S. America)
  23. Infection caused by inhalation of spores
    •Coccidiodes immitis is considered to be the most virulent of fungal pathogens.
  24. Opportunistic Mycoses
    • •Fungal infections that do not normally cause disease in
    • healthy people, but do cause disease in people with weakened immune defenses (immunocompromised people).
  25. prime importance in the occurrence of vaginal candidiasis
    Local factors such as pH and glucose concentration (under hormonal control) 
  26. Protozoa General Characteristics:
    • Unicellular eukaryotes.
    • Animal-like
    • Limited to a moist environment because they lack a cell wall
    • Heterotrophs
  27. Fungi reproduce asexually by 
    • 1.fission (one cell divides to form 2 identical daughter cells and budding
    • 2.schizogony (multiple fission). 
  28. Sexual reproduction occurs by 
    • 1.conjugation: the fusion of vegetative cells
    • 2.fusion of specialized gametes called gametocytes.
  29. Life cycle
    • Some have complex life cycles
    • Requiring multiple hosts and changing their morphology 
    • Plasmodium uses the mosquito as an intermediate host
  30. Trophozoite
    • active, motile, feeding stage of protozoans; parasitic stage
    • that causes the disease in the host
  31. Cyst
    resistant, inactive stage; how diseases are usually transmitted by the fecal-oral route; usually more useful than trophozoites for lab identification
  32. Classification based on mode of 
    locomotion or motility
  33. Sarcodina
    • Move by means of pseudopodia or "false feet"
    • Temporary extensions of the cell body caused by protein filaments of the cytoskeletonpushing on the cell membrane)
    • Feed on algae, bacteria, and other protozoans by phagocytosis.
  34. Mastigophora or Zoomastigophora
    • Move by means of flagella
    • Some can also have pseudopodia
    • Many are disease-causing species
    • Some are parasites
  35. Ciliophora
    • Move by means of cilia
    • Cilia are short, hairlike projections of cytoplasm composed of pairs of microtubules surrounded by cell membrane.
    • Multinucleate organisms
    • Macronucleus controls cell functions and asexual reproduction.  
    • Micronucleus is also involved with sexual reproduction.
  36. Apicomplexa or Sporozoa
    • Basically nonmotile. 
    • All have an infectious, sporelike stage (sporozoite) that is often transmitted to new hosts by an insect vector. 
    • All are parasitic (obligate parasites - cannot live apart from the host).  
    • Some have elaborate life cycles, changing body form (trophozoite, sporozoite, merozoite)
    • Life cycle includes schizogony (multiple fission).
  37. Protozoan Diseases 
    Several serious human diseases:
    • Ameobiasis
    • Chaga’s disease
    • Malaria
    • African sleeping sickness
    • Leishmaniasis 
    • Taxoplasmosis.
  38. Trypanosoma
    (African sleeping sickness)
    • Flagellated protozoans
    • TseTse fly carries
    • Stages:
    • --Systemic: multiplies in blood
    • --Progresses to neurological stage, infects central nervous system   → meningoencephalitis 
    • --Loss of consciousness.  Hence, the SLEEP part.
  39. Malaria caarried by the
    • Anopheles Mosquito 
    • ----Plasmodium. falciparum– most virulent and prevalent
  40. Define Vectors 
    (insects) that convey a parasite from host to host
  41. Protozoas are unicellular
  42. Helminths
    • Multicellular 
    • Eukaryotes
    • Heterotrophs
    • Reside in humans, but do not usually replicate there
    • Not intracellular
    • Most infected individuals carry few, immune system not heavily engaged, level of immunity generated is often poor
  43. Define Cephalization
    Concentration of sensory receptors toward the anterior end
  44. Flatworm sexual reproduction 
    Most are monoecious (Male & Female) both reproductive organs in same animal 
  45. Sexual reproduction in roundworms 
    Dioceious (Seperate Sexes)
  46. Types of Helminths 
    Flat and round worms
  47. Describe Platyhelminthes
    • Flatworms 
    • Most are free living 
    • Marine and Freshwater 
    • Predator, Scavengers, or Parasitic 
    • Some have regenerative capabilities
  48. Trematodes + Cestodes =
    Flatworms = Platyhelminthes
  49. Trematoda  (Flukes)
    • All parasitic of vertebrates
    • Have complex life cycles that include sexual and asexual phases
    • They require at least 2 kinds of organisms to complete the cycle
    • They reach sexual maturity in a primary or definitive host (always a vertebrate), their larval stages develop or become encysted in an intermediate host (usually an invertebrate).
  50. Cestoda (Tapeworms) 
    • Intestinal parasites of vertebrates
    • No digestive system like in trematodes & nematodes
    • They absorb nutrients through their tegument! 
  51. Tapeworm Morphology
    • Scolex (head) with suckers and/or hooks (for attachment)
    • Proglottids (body units - each one has male and female reproductive organs)
    • 1.immature proglottids (closest to the scolex)
    • 2.mature proglottids (next closest to the scolex)
    • 3.gravid proglottids (furthest from the scolex - in these proglottids, the uterus is filled with eggs).
  52. Life cycle
    • The gravid proglottids break off and are passed in the definitive host's feces
    • Larval forms hatch when the eggs are ingested by the intermediate host
    • Larvae then encyst in the intermediate host (called a cysticercus or bladder worm)
    • Adult worms usually develop in the definitive host when raw or poorly cooked infected meat is eaten.
  53. larvae encyst in the intermediate host (called a 
    cysticercus or bladder worm
  54. What part of the body may harbor cysticerci. 
    Every organ in the body 
  55. When a cysticercus dies, it releases
    toxins and usually causes a severe allergic reaction, which is sometimes fatal.
  56. Nematoda Characteristics
    • Nematodes are everywhere!!!! 
    • They are freeliving in soil, fresh & salt water, & are parasitic in plants and animals.
    • Dioecious (separate sexes).
    • •Possess
    • a nonliving cuticle, which is secreted by the epidermis and is resistant to the
    • digestive enzymes of the hosts.
    • More highly developed than flatworms.
    • Adults do not latch onto the host like the tapeworms
  57. Ascaris
    roundworms in the small intestine
  58. Schistosoma
    trematode worm causing debilitating infection
  59. Taenia 
    Tapeworm of cattle and pigs
  60. Trichinella
    roundworm of pigs causing Trichinosis
  61. Schistosomiasis
    3 major species: 
    • –S. mansoni (intestinal mesenteric veins)
    • –S. japonicum (intestinal mesenteric veins) 
    • –S. haematobium (urinary bladder veins
  62. Snails release 300-3000
    cercariae (free swimming larvae)
  63. Cercariae secrete digestive 
    digestive enzymes and bore into skin
  64. Schistosomiasis Symptoms
    • •½ the eggs can remain: invade intestinal wall, liver, or bladder → hemorrhage
    • Unexcreted eggs induce
    • cell-mediated delayed type hypersensitvity.  Large granulomas are formed and walled off by fibrous tissue
    • Granulomas often obstruct venous blood flow to the liver or bladder.
    • Survive for up to 20 years evading attack of localized cellular buildup of immune andinflammatory cells
  65. Taenia solium
    • (Pork Tapeworm) 
    • Humans can be infected with the adults by consuming rare pork containing cysticerci larvae
    • Larvae then develop into adults in digestive tract of the human.
  66. Ascaris lumbricoides
    • Largest intestinal nematode (round worm) in humans.
    • Disease is called ascariasis 
    • Eggs can remain viable even in preservative! 
    • Females are longer; males are shorter & have a hooked posterior end
  67. Helminths are 
    Multicellular eukaryotes
  68. Two types of helminths (worm-like parasites):
    • flatworms and roundworms
  69. Most common route of infection caused by Helminths is by
    Eating uncooked meat
  70. Viruses
    • General characteristics
    • Life cycle
    • Growing virus
    • Viral infections
    • Other acellular organisms
  71. Virus Characteristics
    • Obligate intracellular parasites (can reproduce/replicate only inside a host cell)
    • Not cells
    • Consist of nucleic acids (DNA or RNA) in a protein coat, called a capsid (no cell membrane)
  72. Virus insert themselves into a host 
    host cell & direct the host cell's metabolic machinery to make more virus
  73. Viruses can attack 
    all cellular organisms
  74. Characteristics of living things: 
    • 1. reproduction
    • 2. metabolism
    • 3. organized as cells, contain all organic molecules (lipids, enzymes, nucleic acids, carbs)
    • 4. evolution & adaptation to changing environments.
  75. What characteristics do viruses have
    • They can evolve
    • They contain some macromolecules
    • They direct their own reproduction
    • However, they are not cells - they do not have cytoplasm, a cell membrane, organelles, ribosomes, or a nucleus. 
    • They have DNA or RNA, unlike prokaryotic and eukaryotic cells, which have both.   
    • In addition, they lack a metabolism of their own (they cannot produce ATP, etc.) - raw materials and driving force (ATP & reducing power) are supplied by the host cell.
  76. Viruses are classified by
    • Size
    • Structure
    • Host range
    • Life cycles
  77. Basic structure of a virus is a
    nucleic acid surrounded by a protein capsid
  78. Describe a virion 
    • A complete viral particle (= capsid + nucleic acid + envelope if it is present) 
  79. Viruses store their genetic info in the
    Nucleic Acid
  80. Viruses protein coat that surrounds the nucleic acid is called 
  81. the constituent protein molecules making up the capsids are called
  82. 3 basic shapes based on how the capsomeres are arranged
    • Helical 
    • Polyhedral 
    • Complex
  83. Helical 
    proteins fit together as a spiral to form a rod-shaped structure
  84. Polyhedral 
    • proteins are arranged in equilateral triangles that fit together to form a geodesic dome-shaped structure; some appear almost spherical; you may have seen
    • architectural structures that have this shape
  85. Complex 
    combination viruses with a helical portion (tail) attached to a polyhedral portion (head); ex. many bacteriophages; may also have a tail sheath (participates in injecting the viral nucleic acid into the host cell), plate, pins, & tail fibers (help virus attach to host cell).
  86. Viruses that lack envelopes are called
    Naked Viruses
  87. Envelopes also help viruses infect new cells by
    Fusion of the envelope with the host's cell membrane
  88. Viral specificity is determined by whether or not a virus can
    • Attach to a cell
    • Attachment depends on the presence specific receptor sites
  89. Examples of receptor sites are
    Proteins, LPS’s, glycolipids, or glycoproteins.
  90. Lytic Cycle: Replication 
    • a.  Adsorption - the virion attaches itself to a
    • specific receptor site on the surface of the host cell.
    • b.  Penetration - the viral nucleic acid penetrates the host cell
    • c. Uncoating - removing the capsid & envelope
    • d.    Viral Synthesis (Latent Period) (also
    • called biosynthesis) - more viral components 
  91. Virus remains latent for many cellular generations by becoming
    integrated into a host cell's chromosome (the integrated viral DNA is called a prophage
  92. Produce population of bacteria infected with the prophage occurs by 
    Cell division
  93. Cultivating Animal Viruses is done more economical & efficient by
    Embryonated chicken eggs 
  94. measles virus causes the membranes of neighboring cells to 
    fuse, creating giant, multinucleated cells. (Infection that can be seen under the microscope
  95. large group of RNA viruses; includes 
    • HIV
    • (Human Immunodeficiency Virus) which causes AIDS (acquired immune deficiency syndrome); infects T cells (type of white blood cell).
  96. Retroviruses
    Retro means "backward."  This virus uses the enzyme 
    enzyme reverse transcriptase to make DNA from its RNA.  This DNA can be integrated into the host cell's chromosome
  97. AZT (azidothymidine), which is used against 
    HIV, helps stop reverse transcription by targeting the enzyme reverse transcriptase
  98. Tumors 
    uncontrolled growth of tissue (cells are dividing out of control); most are benign (non-life threatening); some are malignant (they spread or metastasize to surrounding tissues).
  99. Cancer
    malignant tumors that metastasize to surrounding tissues
  100. Tumors and Cancer Causes
    Most human cancers arise form genetic mutations or cellular damage caused by environmental factors (chemicals - nicotine, pesticides; radiation - UV, X-rays, etc.; diet).  About 15% are attributed to viral infections.
  101. Viruses and Cancer Examples:
    • Human T-cell leukemia (blood cancer),
    • Epstein-Barr virus causes Burkitt's lymphoma
    • Hepatitis B virus causes hepatocellular carcinoma (liver cancer)
    • Human papillomavirus causes skin & cervical cancers.
    • Kaposi’s sarcoma – thought to be associated with herpesvirus
  102. infectious particle
    • Viroids: circular molecule, dont produce proteins, cause plant disease 
    • Prions: Infectious agent composed only of protein, affect CNS, 
  103. Fungi are 
    eukaryotes that can cause mycoses
  104. Protozoa are
    unicellular animal-like eukaryotes
  105. Helminths are 
    are multicellular parasites
  106. Viruses, viroids and prions are 
    are acellular infectious agents