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Option FMicrobes and Biotechnology Abi S. Eleah W.
There are three domains of living organisms: Archaea, Eubacteria, and Eukaryota. Archaea are the most basic and live in extreme conditions; for example, they have no histone proteins, cell wall, or introns. Eubacteria are more advanced, with a cell wall and many different shapes (cones, comma-shaped, spirals, etc.), and Eukaryota are the most advanced, with histone proteins and introns.
Types of bacteria: • Methanogens- obligate anaerobes • Thermophiles- live in warm areas with temperature close to boiling • Halophiles- live in saline habitats • Gram positive- simple cell wall one layer thick • Gram negative- several cell walls with peptidoglycan between • Viruses- have naked or enveloped capsids
Six specific bacteria classes • Saccharomyces-heterotrophs, use extracellular digestion, no method of locomotion • Amoeba- heterotrophs, use pseudopodia to move • Plasmodium-heterotrophs that use intracellular digestion, slide on substrate • Paramecium-heterotrophs, intracellular digestion, swim using cilia • Euglena-autotrophs and heterotrophs, swim using flagella • Chlorella-autotrophs, no locomotion
Nitrification/Denitrification- bacteria in soil and on root nodules fix nitrogen, convert ammonia into nitrites and nitrites into nitrate, and remove nitrogen from the soil to release into the atmosphere • Methane creation- Eubacteria turn inorganic material into organic material, which becomes acetate, carbon dioxide, and hydrogen. Methanogenic bacteria create water and methane and break down acetate to create methane and carbon dioxide.
Sewage Treatment • Raw sewage in rivers and lakes increases saprotrophs numbers to break it down, which causes biochemical oxygen demand and increased organism death. Algal blooms and eutrophication results. • Trickling filter beds- bed of stones with saprotrophs that break down waste • Reed bed system- waste put into reed beds, which contain saprotrophs to break down waste (which also fertilizes the reeds)
Forms of gene therapy • Reverse transcriptase- makes DNA from RNA • Somatic- replaces body cells in an individual • Germ line- treating gametes and genes • Viral vectors- replace defective genes in a host organism • Can be dangerous
Alcohol and bread production • Beer- Saccharomyces ferments barley and malt to produce beer containing ethanol and carbon dioxide • Wine- yeast ferments grapes until ethanol kills the bacteria • Bread- bacteria ferments sugars to produce the carbon dioxide that causes bread to rise until the heat of baking kills them (before alcohol is produced) • Soy sauce- Aspergillusoryzae is mixed with soy beans and wheat, salt and water are added after an incubation period, and then it is left for months while fermentation occurs
Preservation- acid kills bacteria before they can break down material and sugar/salt draw water out of microbes through osmosis to kill them • Food poisoning- one example is salmonella, which is obtained from raw eggs, meat, and fecal matter; it lives in the intestine of the host and causes digestive problems
Photoautotroph: • An organism that uses light energy to generate ATP and produce organic compounds from inorganic substances. • Ex: Cyanobacteria (e.g. Anabaena) • Photoheterotroph: • An organism that uses light energy to generate ATP and obtains organic compounds from other organism. • Ex: Rhodospirillum; Rhodobacter
Chemoautotroph: • An organism that uses energy from chemical reactions to generate ATP and produce organic compounds from inorganic substances. • Ex: Nitrobacter • Chemoheterotroph: • An organism that uses energy from chemical reactions to generate ATP and obtain organic compounds from other organisms. • Ex: Mycobacterium tuberculosis; Lactobacillus
Photoautotrophs vs. Photoheterotrophs • Both create ATP from light • Photoautotrophs use CO2 as carbon source • Photoheterotrophs use organic molecules as carbon source
Chemoautotrphs vs. Chemoheterotrophs • Chemoautotrophs get energy from chemicals and carbon from inorganic compounds • Chemoheterotrophs get energy and carbon from organic compounds
Bioremediation • Use of microbes, fungi, plants or enzymes to remove environmental contaminants from water and soil by breaking down the chemicals or converting them so that they can be filtered out
Oil Spills: • Microbes oxidate hydrocarbons • Pesticide Pollution: • Microbes gradually break down pesticides • Selenium pollution: • Microbes absorb selenium ions and oxidate them into the less toxic metallic selenium • Solvent pollution: • Microbes dechlorinate solvents in anaerobic conditions
Methods of pathogen transmission • Ingestion of food can transmit food poisoning • Polluted or unclean water can cause disease • Air/ water droplets in the area can carry organisms • Animal vectors • Puncture wounds/ cuts break the skin barrier and allow entry of bacteria or viruses. • Sexual contact with an infected person
Intracellular bacterium such as Chlamydia rely on host's metabolism for certain of metabolic processes. Chlamydia specifically lives within the epithelial cells of that line the genital tract. It does not produce toxins nor directly damage cells, but can cause long-term problems which remain unremedied by the immune system because they are not detectable inside the cells • Extracellular bacterium such as Streptococcus live inside the host, but in the intercellular spaces and use the nutrients available there while producing toxins and damaging cells. Streptococcus produces toxins that kill host cells and molecules called invasins which split open and dissolve host cells. Unlike Chlamydia, it is targeted by the immune system as an infection.
Endotoxins: lipopolysaccharides in the walls of Gram-negative bacteria that cause fever and aches. • Exotoxins: specific proteins secreted by bacteria that cause symptoms such as muscle spasms (tetanus) and diarrhea.
Irradiation • Some microbes are resistant to ionizing radiation • Free radicals may alter the flavour • Some consumers are afraid to use products of 'radiation' Pasteurization • Application of alternating extreme high and low temperatures is very effective at killing pathogens if done for long enough in the correct conditions. • Usually not done because it alters the flavor of the product being pasturized Antiseptics • Kill/prevent microbial growth and prevent infection without damaging skin and mucous membranes, though they are too toxic to be consumed internally Disinfectants • Extremely effective sterilisation that cannot be used on living tissue. • Useful for sterilisation of medical tools, floors, furniture, etc • Does not kill endospores
Antibiotics are antimicrobial agents produced by microbes which inhibit or kill other microbes via cell wall synthesis inhibition, which inhibits the production of peptidoglycan for the cell walls of bacteria, protein synthesis inhibition, which occurs when the antibiotics block some stage of protein synthesis by attacking the bacterial ribosomes, or nucleic acid inhibition, which affects the synthesis of DNA/RNA or attach to DNA/RNA so that they cannot be read and thus interferes with the growth of bacterial cells
Life Cycle of the Influenza Virus • Virus attaches to cell surface by means of specific receptors • Virus is taken up via endocytosis • Uncoating occurs in endosome and viral RNA is released into the cytoplasm • RNA of viral genome transported into the nucleus, where it is copied and replicated by the viral enzyme into RNA, acting as template for more RNA and a messenger • Viral envelope proteins begin to assemble in cell membrane • Lysis, or the bursting of the cell, occurs and releases new virus particles to attack other cells.
Epidemiology is the study of the occurrence, distribution and control of disease.
A pandemic is a very widespread epidemic that affects a large geographic area, such as a continent • Ex: Spanish Flu of 1918 • Killed 40-50 million people • Origin believed to be in China • Travel of soldiers for WWI aided spread of flu • Hang washing encouraged, public gathering banned
Malaria Cause • Plasmodium (falciparum, vivax, ovale, malariae) Transmission • Transmitted from one person to the next by a female Anopheles mosquito which feeds on human blood • Plasmodia reproduce in the gut of the female mosquito • Egg sac ruptures and releases sporozoites which travel to the salivary glands, enter bloodstream with mosquito bite and travel to the liver, at which point they change form, and then invade red blood cells Symptoms/Effects • Anemia, bouts of fever chills, shivering, joint pain, and headache.
Prion Hypothesis • States that the causal agent for spongiform encephalopathies consists only of misfolded proteins (PrPSC). • Abnormally shaped prions that can cause normal proteins (PrPC) to change to an abnormal shape, resulting in cell death. • Chronic, degenerative diseases of the nervous system that form holes in brain tissue, causing memory loss, personality changes, speech lapses and ultimately death.