resistance

Examples of resistance in the following topics:

• Antibiotics: Are We Facing a Crisis?

  • One of the main causes of resistant bacteria is the abuse of antibiotics.
  • The antibiotic kills most of the infecting bacteria; therefore, only the resistant forms remain.
  • These resistant forms reproduce, resulting in an increase in the proportion of resistant forms over non-resistant ones.
  • Because they are given to livestock in low doses, the probability of resistance developing is maximized.
  • These resistant bacteria are readily transferred to humans.

• The Work of Breathing

  • Breathing includes several components, including flow-resistive and elastic work; surfactant production; and lung resistance and compliance.
  • There are two types of work conducted during respiration: flow-resistive and elastic work.
  • When the respiratory rate is increased, the flow-resistive work of the airways is increased and the elastic work of the muscles is decreased.
  • When the respiratory rate is decreased, the flow-resistive work is decreased and the elastic work is increased.
  • Explain the roles played by surfactant, flow-resistive and elastic work, and lung resistance and compliance in breathing

• Biofilms and Disease

  • Biofilms, complex colonies of bacteria acting as a unit in their release of toxins, are highly resistant to antibiotics and host defense.
  • Once established, they are very difficult to destroy as they are highly resistant to antimicrobial treatments and host defense.
  • Once an infection by a biofilm is established, it is very difficult to eradicate because biofilms tend to be resistant to most of the methods used to control microbial growth, including antibiotics.
  • It has been said that they can resist up to 1,000 times the antibiotic concentrations used to kill the same bacteria when they are free-living or planktonic.

• Ecosystem Dynamics

  • Ecosystems are controlled both by external and internal factors; they can be both resistant or resilient to ecosystem disturbances.
  • In ecology, two parameters are used to measure changes in ecosystems: resistance and resilience.
  • Resistance is the ability of an ecosystem to remain at equilibrium despite disturbances.

• Genetic Engineering

  • In the US, GMOs such as Roundup-ready soybeans and borer-resistant corn are part of many common processed foods.
  • Borer-resistant corn is an example of a genetically- modified organism made possible through genetic engineering methods that allow scientists to alter an organism's DNA to achieve specific traits, such as herbicide resistance.

• Intermediate Filaments and Microtubules

  • Microtubules are part of the cell's cytoskeleton, helping the cell resist compression, move vesicles, and separate chromosomes at mitosis.
  • They help the cell resist compression, provide a track along which vesicles move through the cell, and pull replicated chromosomes to opposite ends of a dividing cell.

• Misconceptions of Evolution

  • For example, applying antibiotics to a population of bacteria will, over time, select a population of bacteria that are resistant to antibiotics.
  • The resistance, which is caused by a gene, did not arise by mutation because of the application of the antibiotic.
  • The gene for resistance was already present in the gene pool of the bacteria, probably at a low frequency.
  • The antibiotic, which kills the bacterial cells without the resistance gene, strongly selects individuals that are resistant, since these would be the only ones that survived and divided.
  • Experiments have demonstrated that mutations for antibiotic resistance do not arise as a result of antibiotics.

• Agricultural Diversity

  • Every plant, animal, and fungus that has been cultivated by humans has been bred from original wild ancestor species into diverse varieties arising from the demands for food value, adaptation to growing conditions, and resistance to pests.
  • Resistance to disease is a chief benefit to maintaining crop biodiversity; lack of diversity in contemporary crop species carries similar risks.

• Modern Applications of DNA

  • Still, therapeutic cloning efforts have met with resistance because of bioethical considerations.
  • In the US, GMOs such as Roundup-Ready soybeans and borer-resistant corn are part of many common processed foods.

• Genetically Modified Organisms (GMOs)

  • Manipulating the DNA of plants (or creating genetically modified organisms called GMOs) has helped to create desirable traits, such as disease resistance, herbicide and pesticide resistance, better nutritional value, and better shelf-life.
  • The Ti plasmids carry antibiotic resistance genes to aid selection and can be propagated in E. coli cells as well.