WGU D311 Micro Section 1

WGU D311 Micro Section 1 What are characteristics of Prokaryotic Cells "Bacteria" - ANS Single celled, do not have nucleus, mitochondria or chloroplast, multiple shapes (coccus, bacillus, vibrio, etc) found in pairs, clusters or chains What are characteristics of Eukaryotic cells "animal and plant cells" - ANS Have a nucleus, have membrane bound organelles, single celled or multicellular, larger than prokaryotes, linear histone wrapped chromosomes Differences between Prokaryotes and Eukaryotes - ANS All plants and animal cells (protozoans , algae, fungi) are Eukaryotic. bacteria and archaea are Prokaryotic Structures if Eukaryotic: nucleus, membrane organelles in the cytoplasm ( mitochondria, endoplasmic reticulum, Golgi apparatus, lysomes, and peroxisomes held in place by the cytoskeleton. Flagella (whip like/flexible) and cilla Structures of Prokaryotic: cell membrane, chromosomal dna that is in nucleotide, ribosomes, and cell wall. Flagella (stiff/rotating) pilli, fimbriae and capsules Bacteria - ANS Found in every habitat on earth, prokaryotic, cell walls have peptidoglycan and described by shape (coccus, bacillus, spirillum, spirochete or vibrio) Protists - ANS A eukaryotic organism that cannot be classified as an animal, plant, or fungus. Fungi - ANS Eukaryotic, lives by decomposing and absorbing nutrients. Not photosynthetic and has cell wall made of chitin Helminths - ANS multicellular parasitic organisms commonly called worms or flukes ex: Guinea worm (Dracunculus medinensis) Viruses - ANS Acellular, consists of proteins and genetic material (dna/rna) never both Bacterial Structures "prokaryotic" - ANS Nucleoid, ribosomes, endospores, plasma membrane, cell wall, peptidoglycan, flagella, fimbriae, pilli Nucleoid of Bacteria - ANS central area in a prokaryotic cell that contains genetic information, not surrounded by a membrane Ribosomes of Bacteria - ANS site of protein synthesis. 70S composed of two subunits (30S small and 50S large and are composed of protein and rRNA components Endospores of bacteria - ANS form around DNA when stressed, protect until conditions are good Plasma membrane in bacteria - ANS phospholipid bilayer with embedded proteins that defines the boundary of the cell Cell wall of bacteria - ANS made of peptidoglycan and help maintain shape and withstand changes in osmotic pressure Peptidoglycan of bacteria - ANS is part of the cell wall. is made of sugars and proteins. Flagella of bacteria - ANS acts as a propeller to move the cell. Stiff, rotating structure. Fimbriae of bacteria - ANS hairlike bristles that allow adhesion to surfaces Pili of bacteria - ANS Appendages that allow bacteria to attach to each other and to transfer DNA Chemotaxis - ANS Directional movt from a call in response to chemical attraction Phototaxis - ANS movement in response to light using flagella Bacterium "runs" - ANS Movt of bacteria counterclockwise flagellar rotation Bacteria "tumbles" - ANS Random movt of bacterial cell by clockwise flagellar rotation vegetative cell - ANS metabolically active and growing and does not contain endospores. Sensitive to extreme temps and radiation, gram positive, normal water content Endospores - ANS A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions (extreme temps and radiation) does not absorb gram stain. No growth Why is sporulation important for bacteria - ANS Protects bacteria agaisnt degrading agents, unfavorable growth and nutrient depletion What are 6 steps of sporulation process - ANS DNA replicates, membranes form around dna, forespore forms additional membranes, protective cortex forms around the spore, protein coat forms around the cortex and spore is released Gram Negative cell - ANS More complex, 3 layers (inner membrane, thin layer if peptidoglycan and outer membrane containing lipipolysaccharide) Gram positive cell - ANS Simple structure, thick layer of peptidoglycan with teichoic acid Gram Negative structure - ANS Lipopolysaccharides: outer membrane Periplasmic space: b/T cell wall and plasma membrane outer membrane: phospholipid bilayer external to the peptidoglycan layer All viruses have ? - ANS capsid and nucleic acid Capsid - ANS protein coat surrounding a virus naked virus - ANS no envelope. Composed of nucleic core either dna or rna enveloped virus - ANS a virus formed with a nucleic-acid packed capsid surrounded by a lipid layer. Made up of phospholipid membrane that buds from the host cell. Hyphae (Fungi Structure) - ANS Branching, threadlike tubes that make up the bodies of fungi Mycelium (fungi structure) - ANS Negative network of branched, tubular hyphae Thallus (fungi structure) - ANS Body of fleshy fungi. Commonly occurs with HIV infection and fungal reproduction. Microbes move to the lymphatic system in the groin Dimorphic fungus - ANS Fungi that are capable of growing in both the mold form and the yeast form ex: human pathogens Histoplasma capsulatum (lung dx) and Candida albicans (vaginal yeast/oral thrush) Ascomycota - ANS Yeast, sexual reproduction. Edible mushrooms, truffles and PCN Basidiiomycota - ANS Club fungi, rust, puffballs and mushrooms Microsporidia - ANS lack mitochondria, produce polar tube Zygomycota - ANS bread molds What groups are protist - ANS Algae, Protozoa, slime mold and water molds Characteristics of protozoans - ANS eukaryotic organisms that are not fungi, plants, or animals. Single celled, free living, lack cell wall, divide by binary fusion or budding two groups of parasitic helminths - ANS flatworms and roundworms Characteristics of Nematoda (Round worms) - ANS Full digestive system, contain more than 15000 species. Pinworm is most common in US Characteristics of platyhelminthes (flukes/tapeworms) - ANS Flukes: nonsegmented flatworms that have oral sucker, attach to inner walls of intestines, lungs, large blood vessels or the liver Tapeworms: segmented flatworms that may have suckers at the head region, attach to wall of small intestine homolactic fermentation - ANS produces lactic acid only heterolactic fermentation - ANS Mixture of lactic acid, ethanol and co2 acetone-butanol-ethanol fermentation - ANS industrial solvents. Kills clostridium acetobutylicum alcholic fermentation - ANS Microbes: Candida, Saccharomyces commercial: beer and bread butanediol fermentation - ANS Microbes: Klebsiella, Enterobacter, Commerical: Chardonnay wine butyric acid - ANS Microbes: clostridium butyricum Commerical: butter lactic acid fermentation - ANS Microbes: strep, lactobacillis, commerical: yogurt, cheese and sauerkraut mixed acid fermentation - ANS Microbes: esherichia, shigella commerical: vinegar, cosmetics, pharmaceuticals Proprionic acid - ANS Microbes: propionibacterium, Bifidobacterium commercial: Swiss cheese Purpose of bioremediation - ANS Stimulate microorganisms with nutrients and other chemicals that will enable them to destroy contaminants. Xenobiotics - ANS Things that humans pollute the air with and are more than what naturally happen. Bacteria that helps with this is Rhodococcus and Pseudomonas degrade contaminants found in oil and co2 gene therapy - ANS the transplantation of normal genes into cells in place of missing or defective ones in order to correct genetic disorders. What does gene therapy use - ANS viruses bc it has the ability to deliver genetic material into the cells risks of gene therapy - ANS Inflammation: lead to organ failure Toxicity: virus can change to be infect Cancer: disrupt normal cell cycling and cause tumor formation synthetic antimicrobials - ANS manufactured by chemical processes not found in nature ex: sulfanilamide, which led to production of Quinolones and Oxazidinones natural antibiotics - ANS Produced by microbes in nature ex: PCN in mold to treat streptococcus, meningococcal semisynthetic antimicrobials - ANS chemical modification of naturally occurring antibiotics. This allows for more bacteria to be targeted, increase stability and decrease toxicity Pathogenicity - ANS ability to cause disease Virulence - ANS severity of disease median infectious dose (ID50) - ANS the number of pathogenic cells/viruses needed to cause infection in 50% of inoculated animals median lethal dose (LD50) - ANS The number of pathogenic cells/viruses/toxins needed to kill 50% of infection animals Primary pathogen - ANS causes disease in healthy host opportunistic pathogens - ANS cause disease in immunocomprised individuals What is positive about bacteria - ANS Bacteria are everywhere skin: beneficial, keeps harmful bacteria from growing digestive system: break down food and absorb vitamins ecosystem: decompose, fix nitrogen that plants need virulence factors - ANS traits used to invade and establish themselves in the host, also determine the degree of tissue damage that occurs - severity of disease Streptococcus pyogenes - ANS strep throat- protein F- resp epithelial cells Streptococcus mutans - ANS dental caries- adhesion P1- teeth Neisseria gonorrhoeae - ANS gonorrhea- type IV pili- urethane epithelial cell Enterotoxigenic escherichia coli - ANS traveler's diarrhea- type 1 Fimbriae- intestinal epithelial cells Vibrio cholerae - ANS cholera- N methylphenidate- intestinal epithelial cells antigenic variation - ANS Alter surface proteins so the pathogen is not recognized by the host immune system How can microorganisms evade the immune system ? - ANS Antigenic variation, bacteria produce capsules, acid fast bacterium produce waxy substances/ mycolic acid Influenza virus - ANS Dz: influenza attach: Hemagglutinin/ sialic acid of resp intestinal cells Herpes simplex virsus - ANS Dz: oral/genital herpes attach: Glycoproteins gab, gC, gD. Heparin sulfate on mucosal surfaces of mouth and genitals human immunodeficiency virus - ANS Dz: HIV attach: Glycoprotein gp 120- CD4 and CCR5 or CXCR4 of immune system cells antigentic shift - ANS A MAJOR change in the antigentic structure of the causal agent due to the recombination of the genetic material from two different strains of the causal agent. More dangerous Antigenic drift - ANS Minor change in influenza virus antigens due to gene mutation Virulence factors for Candida albicans (fungus) - ANS Surface glycoprotein. invades proteases, keratinase, and phospholipase cause oral thrush and vaginal yeast infection Virulence factor for cryptococcus (fungus) - ANS Capsule made of glucuronoxylomannan cause pneumonia and meningitis Virulence factors for claviceps (fungus) - ANS Ergot toxin (myocotoxins) grows on rye/grains cause gangrene and convulsive Virulence factors for aspergillus (fungus) - ANS Myocotoxin Aflatoxin- carcinogen enters body thru contaminated food or inhalation Myocotoxins - ANS Fungal toxins/ poisonous can be toxic when they eat, absorbed into the skin or inhaled. Can cause death. Virulence factor of Giardia lamblia (protozoan) - ANS Large adhesion disk uses flagella to draw fluid out that lowers pressure = facilitate adhesion intestinal disease Virulence factor Plasmodium falciparum (protozoan) - ANS Antigenic variation. Adhesion membrane protein called PfEMP1. RBC stick together stop blood flow malaria Virulence factor Trypanosoma Brucei (protozoan) - ANS Capsules and antigenic variations African Sleeping Sickness Virulence factors with Helminths - ANS Parasitic worms large and evade immune system roundworms protected by tough outer cuticle glycan "Gimmickry" resembles host cells, immune system fails to recognize the attack suppress immune system or make the immune system respond inappropriately Bacteremia - ANS bacteria in the blood septicemia - ANS growth of bacteria in the blood and multiplying Viremia - ANS viruses in the blood Toxemia - ANS toxins in the blood Exoenzymes - ANS Produced by pathogens that enable them to invade host cells and deeper tissues function of glycohydrolases (exoenzymes) - ANS Degrades hyaluronic acid that cements cells together to promote spreading through tissues Ex: Hyaluronidase S in staph aureus Function of nucleuses (exoenzyme) - ANS Degrade DNA released by dying cells that can trap bacteria = spreading Ex: DNAse produced by S. aureus Function of phospholipases (exoenzyme) - ANS Degrade phospholipid bilayer of host cells= phagosomes escape into the cytoplasm Ex: Phospholipase C of bacillus anthracis Function of proteases (exoenzyme) - ANS Degrades collagen in connective tissue to promote spread Ex: Collagenase in Clostridium perfringens Collagenase - ANS Exoenzyme that has metal ion, digest collagen Pathogen that uses Collagenase - ANS Gram positive bacterium Clostridium perfringens. Causes widespread necrosis of tissue DNAse - ANS degrades DNA so it can escape and spread thru the tissue Pathogen that uses DNAse - ANS S. aureus produces DNAse to degrade and escape the extra cellular DNA produced by the immune system phagocytes to trap the bacteria Hyaluronidase - ANS Produced by pathogens to break down the hyaluronic acid between adjacent cells in connective tissue Ex: staph, step Toxins - ANS Produced by pathogens. Biological poisons that assist in the ability to invade and cause damage to tissues Toxigenicity - ANS Ability to produce toxins that will cause damage to the host What are two types of toxins - ANS Endotoxins and exotoxins Endotoxins - ANS lipopolysaccharide components of the outer membrane of gram-negative bacteria Exotoxins - ANS Protein molecules that are produced by living pathogenic bacteria majority are produced by Gram Positive pathogens heat liable very small concentrations of exotoxins are lethal botulism Intercellular targeting toxins - ANS Cholera Toxin Tetanus toxin - ANS Clostridium tetani, release inhibitory neurotransmitters in the CNS= spastic paralysis Botulinum toxin - ANS Clostridium botulinum- neurotransmitter acetylcholine= flaccid paralysis Diphtheria toxin - ANS inhibits protein synthesis = cellular death Membrane disrupting toxins - ANS cause lysis of host cells by disrupting their plasma membranes Ex: streptococcus pneumonia Alpha toxins - ANS Break down cell membrane, disrupts membrane function and kills the cell Superantigens - ANS cause an intense immune response due to release of cytokines from host cells Ex: toxic shock syndrome Proteases - ANS enzymes that break down proteins involved with swelling and pain Coagulase - ANS coagulates fibrinogen which results in the clothing of blood Biofilms - ANS Microorganisms grow highly structured complex and dynamic ecosystem provide advantages to microorganisms they are on Advantages of biofilms - ANS Adhesion/ cohesion, nutritional sources, protection and resistance to drugs, host immune attacks (antibodies/complement system) Structure of biofilms - ANS Conditions influence structure filamentous biofilms: rapidly flowing water mushrooms like shape: slow moving water EPS: large part of biofilm,maintains integrity and functions in the biofilm, allows movt of nutrients, waste and gases, Kronos cells hydrated, protect organisms in biofilm from predators Planktonic cell - ANS Free floating cells that lives in water Sessile cell - ANS Biofilm forms/attached to a surface quorum sensing - ANS How biofilms coordinate activities due to environmental stimuli What are examples of biofilms - ANS Beneficial: layers of micro iota lining the intestinal and resp mucosa play a role in warding odd infections by pathogens harmful: plaque that forms in teeth can contribute ti dental and periodontal disease Light microscopy - ANS Use light to see image Structures of bright field microscope - ANS Commonly used 2 or more lenses produce dark image on a bright background ocular lens multiple objective lenses with different magnification levels. highest magnification is 1000x magnification (100x in objective lens and 10x in ocular lens electron microscope - ANS A microscope that forms an image by focusing beams of electrons onto a specimen. 1000 times more detailed than light. Requires a vacuum so no living specimen. What are two types of electron microscopes - ANS Transmission and scanning electron microscopes transmission microscope - ANS Uses electron beam from above the specimen that is focused on magnetic lens then projected through a specimen onto a detector. Electrons pass through the specimen and the detector captures the image scanning electron microscope - ANS 3D Images. Very detailed. Scan a narrow beam of electrons back and forth. Best microscope for biofilms - ANS Confocal microscope wet mount - ANS Simplest type of prep needed for microscopy specimen on slide, drop liquid/stain, coverslip, then exam under scope Fixation - ANS Attach cells to slide by heat or chemicals. kills microorganisms preserves integrity of cellular components Basic dye - ANS Chromophore is positive charge ion Acidic dye - ANS Chromophore is negative charged ion positive stain - ANS stains the organism, not the background positive stain stick with specimen and gives it's color negative stain - ANS Dye is absorbed in background and not by cells. Cells will be outlined against a colorful background simple stain - ANS One dye color/ all the same color differential stain - ANS Uses multiple dyes to differentiate b/t structures (gram stain, acid fast, endospores, flagella, and capsule staining) 4 steps of gram staining process - ANS Differential staining for bacteria with different types of cell walls primary stain: crystal violet applied to heat fixed smear=cells purple mordant added which stabilized dye/stat contained in thick layers of peptidoglycan in cell walls decolorizing agent added. Cells with thick peptidoglycan layers are less affected= stay purple. Cells with thin peptidoglycan layers the dye washes away= colorless counterstain/safranin added. Any decolorized cells are stained pink and this is less noticeable in cells that still have crystal dye (violet) Gram positive - ANS Keep primary stain (purple) thick cell wall, mostly peptidoglycan (60-90%) lipoteichoic and teichoic acid Gram negative - ANS Lose primary stain/ stained by counterstain thin cell wall, peptidoglycan 10-20% periplamsic space=metabolism and extra protection lipopolysaccharide (endotoxin) more pathogenic bc of outer membrane and periplasmic space More dangerous than gram positive/ resistance to antibiotics What is the acid fast stain? - ANS Tell difference between 2 types of gram positive cells (those that have mycolic acid and those that don't) What techniques are used for acid fast stain - ANS Ziegler Neelsen (uses heat) and Kinyoun (no heat) How to use microscopy to diagnose TB - ANS Acid fast Bacilli: smear, stain with heat Immunofluorescence: antibodies bind to M. Tuberculosis. If present the dyes cna be used to view bacteria capsule staining - ANS Capsules do NOT absorb basic dyes bacteria and yeast have capsules use negative staining techniques (background hold color and form halo around cell) capsule= increase ability to cause a disease endospore staining - ANS gram staining alone can't be used to see endospores Use 2 stains. Schaefer-Fulton method, commonly used - Heat to push primary stain into the endospore - retain green stain. Then counterstain pink with safranin. identify Bacillus and Clostridium endospores can survive harsh conditions