Concept explainers
Antibiotics are chemically diverse antimicrobial compounds produced by microorganisms. Each antibiotic works by inhibiting a specific cellular process in the target microorganisms. The β-lactam antibiotics, including penicillins and cephalosporins, target bacterial cell wall synthesis and are the most important class of clinical antibiotics. The aminoglycosides, macrolides, and tetracycline antibiotics selectively interfere with protein synthesis in Bacteria. The quinolones are an important class of synthetic antibacterial drugs that inhibit DNA synthesis. Daptomycin and platensimycin are structurally novel antibiotics that target cytoplasmic membrane functions and lipid biosynthesis, respectively.
What are the common sources for natural antibiotics? How do these antimicrobial drugs differ from growth factor analogs, such as the sulfa drugs? Why are β-lactam antibiotics generally more effective against gram-positive bacteria than against gram-negative bacteria?
Want to see the full answer?
Check out a sample textbook solutionChapter 28 Solutions
Brock Biology of Microorganisms (15th Edition)
- Chlamydia are pathogenic bacteria that must be grown within a eukaryotic host cell. They rely on the host cell for many nutrients, including nucleotides, lipids, and amino acids. It is thus no surprise that when grown in co-culture with a host depleted of any of these metabolites, chlamydial growth declines. However, high levels of certain amino acids also inhibit chlamydial growth. Specifically, the amino acids leucine, isoleucine, methionine, and phenylalanine slow down the growth by inhibiting the amino acid transporter called BrnQ. On the other hand, if valine is present in the medium these amino acids have no effect on BrnQ. Discuss how this might be possiblearrow_forwardResistance to many penicillins is the result of cell wall mutations in a variety of bacteria. True or false?arrow_forwardWhat mode of action for ampicillin? Is it bacteriostatic or bactericidal? https://pubchem.ncbi.nlm.nih.gov/compound/ampicillinarrow_forward
- Part F is the most important.arrow_forwardAmoeboid cells that migrate through our tissues, such as the class of white blood cells known as neutrophils, often do so in a directed manner, triggered, for instance, by chemical signals released by pathogens such as bacteria. Directed migration in response to a chemical stimulus is known as chemotaxis. Part of an efficient chemotactic response is the ability of cells to polarize. As is the case with our structurally-polar polymers like F-actin or microtubules, polarization here refers to an asymmetry in the cells, rather than an electrical charge. In this case, it involves one part of the cell becoming the “front” (or leading edge) and another the rear. In a well-polarized, migrating cell, it’s been observed that an active form of Rac (which, in turn, can activate ARP 2/3) is concentrated towards the front of the cell, whereas an active form of Rho (which, in turn, can activate formin, inhibit cofilin/ADP, and activate myosin II) is found toward the rear of the cell. Based on your…arrow_forwardAmoeboid cells that migrate through our tissues, such as the class of white blood cells known as neutrophils, often do so in a directed manner, triggered, for instance, by chemical signals released by pathogens such as bacteria. Directed migration in response to a chemical stimulus is known as chemotaxis. Part of an efficient chemotactic response is the ability of cells to polarize. As is the case with our structurally-polar polymers like F-actin or microtubules, polarization here refers to an asymmetry in the cells, rather than an electrical charge. In this case, it involves one part of the cell becoming the “front” (or leading edge) and another the rear. In a well-polarized, migrating cell, it’s been observed that an active form of Rac (which, in turn, can activate ARP 2/3) is concentrated towards the front of the cell, whereas an active form of Rho (which, in turn, can activate formin, inhibit ADP, and activate myosin II) is found toward the rear of the cell. Based on your…arrow_forward
- Why are structural analogs of sugar molecules (such as Oseltamivir and zanamivir) effective in treatment of influenza-virus infection?arrow_forwardDraw the amino acid–Schiff base that forms in the breakdown of 3-hydroxykynurenine to yield 3-hydroxyanthranilate in the tryptophan degradation pathway (Fig.) and indicate which bond is to be cleaved.arrow_forwardMatch the antibiotic to its target with bacteria. erythromycin [ Choose ] [Choose ] streptomycin, an aminoglycoside bacterial enzymes involved in folic acid synthesis Bacterial gyrase tetracycline bacterial transpeptidase 70S ribosomes Bacterial RNA polymerase ampicillin Bactrim= trimethoprim + sulfa drug [ Choose ] rifampin [Choose ] ciprofloxacin, a fluoroquinolone [ Choose ] >arrow_forward
- The human intestinal tract is home to a vast, diverse microbial community. The bacteria that comprise this microbial community serve a number of important, beneficial functions. However, some bacterial species have been suggested to play a role in certain forms of cancer. One such bacteria is Fusobacterium nucleatum (i.e., F. nucleatum). Investigators wishing to study the role of F. nucleatum in colorectal cancer developed a new assay for detecting these bacteria in tumor tissue. In controlled experiments, the test was highly sensitive in detecting F. nucleatum and also had high specificity. To examine consistency in their test findings, the investigators also conducted repeat tests in 50 tissue samples. From these repeat tests, the investigators observed that the overall number of samples in which F. nucleatum was detected was almost identical (10 out of 50 on the first test vs. 11 out of 50 on the repeat test); for 9 samples, F. nucleatum was detected on both the initial and the…arrow_forwardVI - BIOMOLECULES Instructions : - Answer the question properly. - Please do not copy here in Bartleby - Explain why did you choose that answer in 3-5 sentences.arrow_forwardSulfanilamide is an antimicrobial drug that mimics the shape of an important substrate for a particular bacterial enzyme, thereby inhibiting the enzyme by binding at the active site. This type of inhibition is known as O1) noncompetitive inhibition. O 2) feedback inhibition. 3) pharmacological inhibition O 4) allosteric inhibition. 5) competitive inhibition.arrow_forward
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning