Questão FC225131
Discover: If you had just $10 for entertainment, how would you spend your day?
Interpretação de Textos (Understanding)
CESGRANRIO · 2012
The Microbial Puppet-Master
by Valerie Ross
from Discover Magazine:
Mind & Brain / Memory, Emotions & Decisions
When Timothy Lu was in medical school, he treated a veteran whose multiple sclerosis was so severe that she had to use a urinary catheter. As often happens with invasive medical devices, the catheters became infected with biofilms: gooey, antibioticresistant layers of bacteria. Now the 30-year-old MIT professor, who first trained as an engineer, designs viruses that destroy biofilms, which cause everything from staph infections to cholera outbreaks and that account for 65 percent of human infections overall.
Discover: You started as an electrical engineer. Was it a difficult transition becoming a biologist?
Lu: I came into the lab not really understanding how to do biology experiments and deal with chemicals. I’m not a great experimentalist with my hands, and one night I set the lab on fire.
Discover: How does a biofilm work, from an engineering perspective?
Lu: A biofilm is essentially a three-dimensional community of bacteria that live together, kind of like a bacterial apartment building or city. Biofilms are made up of the bacterial cells as well as all sorts of other material — carbohydrates, proteins, and so on — that the bacteria build to protect themselves.
Discover: And those communities make bacteria especially dangerous?
Lu: Before I started medical school, I didn’t think bacterial infections were a big deal, because I assumed antibiotics had taken care of them, but then I started seeing patients with significant biofilm infections that couldn’t be cured.
Discover: What is your strategy to destroy biofilms?
Lu: We use viruses called phages that infect bacteria but not human cells. We cut the phages’ DNA and insert a synthetic gene into the phage genome. That gene produces enzymes that can go out into the biofilm and chew it up.
Discover: If you had just $10 for entertainment, how would you spend your day?
Lu: What can you even buy with $10? Maybe I would buy a magnifying glass and just peer around in the soil to see what other life was going on down there. That would actually be fun.
Available at: <http://discovermagazine.com/2011/sep/05-questions-for-microbial-puppet-master>.Retrieved on: 11 Sep. 2011. Adapted.
In Text, Lu reports that his method is successful in
- extracting phages that are infected by a virus that can destroy all enzymes in the bacteria.
- producing an enzyme that is inserted in a genetically marked bacteria to support viruses that live in the biofilm.
- triggering a bacterial infection to the viruses that in turn yield enzymes that potently destroy the biofilm.
- altering a special human-safe virus in order to produce an enzyme that penetrates the biofilm and destroys it.
- inserting a synthetic gene in the phages genome that will affect the production of virus that get organized into biofilms.
Mostrar resposta e comentário
Gabarito
D
Comentário do professor
A alternativa D sintetiza exatamente o método descrito por Lu: ele modifica vírus especiais chamados phages — que atacam bactérias mas são inofensivos a células humanas — para introduzir um gene sintético em seu genoma.
Esse gene passa a codificar enzimas capazes de sair do fago, penetrar o biofilme (a matriz protetora das bactérias) e degradá‑lo, expressão que no texto aparece como “chew it up”.
Assim, a frase “altering a special human-safe virus in order to produce an enzyme that penetrates the biofilm and destroys it” reproduz fielmente os três elementos do relato: vírus direcionados, inserção genética e produção de enzimas que destroem o biofilme.
Conteúdo do catálogo FC Concursos · Atualizado em