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Many of the bacteria responsive for foodborne illnesses do their damage by producing toxins. For example, different populations of the bacterial species Escherichia coli may differ genetically and some genetic differences can transform this normally harmless inhabitant of the human
Bacteria are responsible for most foodborne illnesses. But besides bacteria, which other infectious agents can wreak havoc on the human body?
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Biology
- The beaches at a nearby lake have been closed because of high E. coli counts. The lake is surrounded by agricultural areas and summer cottages. We know that different species of vertebrates have different E. coli strains in their digestive tracts. Propose a hypothesis about the source of the E. coli and design an experiment to test this hypothesis.arrow_forwardEach species of bacteria has its own distinctive cell surface. Thecharacteristics of the cell surface play an important role in processessuch as conjugation and transduction. For example, certainstrains of E. coli have pili on their cell surface. These pili enableE. coli to conjugate with other E. coli and also enable certain bacteriophages (such as M13) to bind to the surface of the E. coli andgain entry into the cytoplasm. With these ideas in mind, explainwhich forms of genetic transfer (i.e., conjugation, transduction,and transformation) are more likely to occur between different speciesof bacteria. Discuss some of the potential consequences ofinterspecies genetic transfer.arrow_forwardHow can this be explained in lamen terms the step by step results of enterobacter aerogenes? DISCUSS all the results. Discuss in a logical and step by step fashion how you concluded that you had a certain microorganism. You need to explain which observation(s) enabled you to identify your unknown microorganism (Enterobacter aerogenes). To convince your reader you need phrases like; This observation “suggested” that my organism is E. coli This observation “confirmed” that my organism is E. coliAlso phrases like; This observation “suggested” that my organism is NOT Enterobacter aerogenesarrow_forward
- Two-component system (TCS) allows an organism in adapting to changes in the environment. It is available mostly in prokaryotes but is also available to some eukaryotes. a) Justify the importance of TCS.arrow_forwardDuring the anthrax crisis of 2001, public health officials urged citizens not to take the antibiotic ciprofloxacin as a preventative measure. Public health officials were concerned that overuse of ciprofloxacin would lead to resistant varieties of anthrax and other bacterial pathogens. Ciprofloxacin is one of the few readily available antibiotics that can treat anthrax. 1)Do you think that public health officials should more directly regulate the availability of ciprofloxacin to ensure its proper use? 2)Why?arrow_forwardAntibiotic resistant bacteria have become a major concern for many public health officials. Widespread use of antibiotics has created an evolutionary pressure on infectious bacteria to develop immunity to these medications. The result is an increase in antibiotic resistant microbes, particularly in settings where antibiotics are commonly used, such as hospitals. One strategy public health officials have devised to counteract these infectious microbes is "antibiotic cycling” where specific antibiotics are withdrawn from the market for a period of several years, then reintroduced as another antibiotic is withdrawn. How would this strategy help limit antibiotic resistance? A. It is impossible for a bacterium to maintain resistance to two antibiotics at once B. When a given antibiotic is not in use, it is an evolutionary disadvantage to carry the unneeded gene C. If a specific antibiotic is removed from the market it is possible to substitute with a related antibiotic such as…arrow_forward
- A graduate student was assaying LD50 (lethal dose 50%) of two temperature-sensitive Francisella tularensis strains in HeLa cells (human cell line). Both strains can infect humans and cause fatal tularemia if untreated, but it is difficult to obtain LD50 values in human subjects. The data below shows LD50 (lethal dose 50%) values of the strains in human cell culture. Can you predict the more virulent strain of the two human pathogens? Francisella tularensis strain A: LD50 @ 20∘C= 100; LD50 @ 37∘C= 1000 Francisella tularensis strain B: LD50 @ 20∘C= 1000 LD50 @ 37∘C= 100 Group of answer choices It is not possible to determine the virulence of the two strains as human pathogens from the provided data Strain A and strain B are equally virulent as human pathogens, as they average out in virulence. Strain A is more virulent than strain A as a human pathogen. Strain B is more virulent than strain A as a human pathogen.arrow_forwardIn light of the COVID-19 pandemic many people are more conscious about cleaning their household surfaces. Your sister says she is going to disinfect the kitchen counter. She sprays on the Lysol antibacterial kitchen cleaneser and immediately wipes off the surface. Is she disinfecting the surface? Explain why or why not?arrow_forward8. Recently, scientists tested the possibility that humangut bacteria may play a role in determining bodyweight. The study subjects were four sets of twins(one set of identical twins and three sets of fraternaltwins), where one twin was of normal weight and theother was obese. Samples of their gut bacteria werecollected and transplanted into bacteria-free mice.Mice with the different bacterial transplants were allfed the same diet and monitored over the course ofabout one month. For each of the four twin pairs, themice with the bacteria from the obese twin gainedsignificantly more weight and fat than the mice transplanted with the bacteria from the normal twin.a. What would you conclude about the relationship between the human gut microbiome and body weight?b. Why were twins used in the study?c. Do the results of this study mean that human genes(genes in the nuclei of human cells) do not play arole in body weight and fat content? Explain.d. Mice are coprophagic, meaning that they eat…arrow_forward
- Erwin Chargaff did not have any DNA samples from thermoacidophilic bacteria such as those that thrive in the geothermal (hot) springs of Yellowstone Park. Such bacteria had not been isolated in 1951 when Chargaff reported his results. If he had obtained such a sample, what do you think its relative G-C content might have been? Why?arrow_forward"On the rapidity of antibiotic resistance evolution facilitated by a concentration gradient" ABSTRACT The rapid emergence of bacterial strains resistant to multiple antibiotics is posing a growing public health risk. The mechanisms underlying the rapid evolution of drug resistance are, however, poorly understood. The heterogeneity of the environments in which bacteria encounter antibiotic drugs could play an important role. E.g., in the highly compartmentalized human body, drug levels can vary substantially between different organs and tissues. It has been proposed that this could facilitate the selection of resistance mutants, and recent experiments support this. To study the role of spatial heterogeneity in the evolution of drug resistance, we present a quantitative model describing an environment subdivided into relatively isolated compartments with various antibiotic concentrations, in which bacteria evolve under the stochastic processes of proliferation, migration, mutation and…arrow_forward"On the rapidity of antibiotic resistance evolution facilitated by a concentration gradient" ABSTRACT The rapid emergence of bacterial strains resistant to multiple antibiotics is posing a growing public health risk. The mechanisms underlying the rapid evolution of drug resistance are, however, poorly understood. The heterogeneity of the environments in which bacteria encounter antibiotic drugs could play an important role. E.g., in the highly compartmentalized human body, drug levels can vary substantially between different organs and tissues. It has been proposed that this could facilitate the selection of resistance mutants, and recent experiments support this. To study the role of spatial heterogeneity in the evolution of drug resistance, we present a quantitative model describing an environment subdivided into relatively isolated compartments with various antibiotic concentrations, in which bacteria evolve under the stochastic processes of proliferation, migration, mutation and…arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning