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A few of the bacteria that commonly cause foodborne illness form endospores . For example, Bacillus cereus. a bacterial species that includes strains that cause vomiting or diarrhea in people unlucky enough to consume them, forms endospores that are widespread in soil and dust. If some spores find their way into warm, moist food, they can develop and give rise to a thriving population of bacteria. B. cereus spores are somewhat resistant to heat, but fortunately for us, they can be destroyed by thorough cooking
Although it is unsurprising that prokaryotes might thrive amidst the energy-rich substances that make up human food, our foodstuffs are hardly the only environment in which prokaryotes flourish. What are some of the more extreme environments in which bacteria and archaea can be found?
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Biology: Life on Earth with Physiology (11th Edition)
- Mycoplasmas are pleomorphic bacteria. How do the unique structural characteristics of mycoplasmas relate to their bacterial morphology? Mycoplasmas have a low G + C genome content. Mycoplasmas appear Gram negative when a Gram stain is performed. Mycoplasmas lack a cell wall. Mycoplasmas form colonies with a fried-egg appearance.arrow_forwardA farmer working on a piece of machinery gets his shirtsleeve caught in a moving piece of the equipment. His shirt is sliced, and a sharp blade covered in mud slices through his upper arm. He attempts to control the bleeding and immediately seeks medical attention. After 3 days, he develops a fever and his arm becomes extremely swollen and painful. Pulling back the bandages, he finds that the wound has become blackened and is leaking bloody fluid. Microscopic analysis of the fluid reveals the presence of gram-positive bacilli. a. Discuss what condition the patient is suffering from and the likely causative agent of this infection. b. Explain how the patient contracted this pathogenic microbe and what virulence factors contributed to the pathogenesis seen at the wound site. c. In addition to antibiotics, the physician prescribes hyperbaric therapy. Describe what this treatment involves and how it could be therapeutic to this patient.arrow_forwardYou are a physician working in a hospital. Your patient is a 65-year-old individual who has been living on the street. Their symptoms include trouble breathing, weakness, and most recently coughing up blood. When gram stained, the bacterium shows no color and most of the antibiotics are not reducing the infection. After reviewing the information from the last physician, you prescribe Isoniazid. Select all of the answers that are correct. Mycolic acid is present in fungal cells Mycolic acid is a waxy substance that can repel many molecules An organism that has mycolic acid has to have access to oxygen and grows very slowly. If there is not gram stain then there is no bacteria present Isonazid targets and destroys mycolic acid. ►arrow_forward
- Why is the fact that Pseudomonas species can grow in nutrient-poorenvironments medically important?arrow_forwardPropionibacterium acnes is a normal member of the skin microbiome that benefits the body by lowering the skin's pH- an antimicrobial effect. However, P. acnes is also the leading cause of acne. Explain mechanistically how can a bacterium be normal and beneficial but also be pathogenic?arrow_forwardDiseases that involve biofilm-producing bacteria are of serious concern. They are not as easily treated compared with those involving free-floating (or planktonic) bacteria. Explain three reasons why biofilms can be more pathogenic.arrow_forward
- About becterial enzymes, it is CORRECT to affirm that: a). Some becterial enzymes can help the microbe fight the immune system, by destroying lgA.b). Coagulases are enzymes that use the host's fibrinogen and form a semi-solid get that isolates amd protects the bacteria.c). Some bacterial enzymes such as hyaluronidase can help the microble move through the host's tissus by destroying the tissue's components.d). Fibrolysin is an enzymes that can help from blood clots.arrow_forwardA dessert chef with a staphylococcal skin infection contaminates his whipped cream with bacteria. In 6 hours, the number of bacteria increases from 450 to 192,000. What is the generation time for this bacteriumarrow_forwardMycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true? They are gram-negative. They are subject to lysis in hypotonic conditions. They lack a cell membrane as well. They should contain less cellulose than do bacteria that possess cell walls. They possess typical prokaryotic flagella.arrow_forward
- Describe the appearance of an S. agalactiae colony grown on blood agar. Describe how that colony would differ in appearance from a colony of S. pyogenes.arrow_forward20. Bacterial spores function in bacterial reproduction . a) Trueb) Falsearrow_forwardDo you think Rickettsia rickettsii can grow on blood agar? Explain.arrow_forward
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