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雅思阅读-071-bacteria-share-proteins-to-survive-antibiotics改编自-scientific-american-带音频

ielts 👁 2 · 💬 0 · 📅 2026-09-14
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雅思阅读 071 — Bacteria Share Proteins to Survive Antibiotics

改编自 Scientific American（2026-07，Jacek Krywko）。研究发表于 Science。

🎧 课文朗读音频（约 1 分半）

Reading Passage

When antibiotics attack microbes, their stressed neighbours ship them proteins to help them survive, new work suggests.

Bacteria share DNA related to antibiotic resistance through a process called horizontal gene transfer, but microbiologists have long suspected they might trade more than just the genes. Multiple papers have proposed that microbes use vesicles — tiny fluid-filled bubbles enclosed in fatty membranes — to ferry functional proteins to their neighbours as well. "But if you go back to these papers, there was no evidence," says Christophe Herman, a microbiologist at Baylor College of Medicine. In a recent study published in Science, Herman and his colleagues have, for the first time, caught bacteria in the act of transferring proteins to each other in this way.

To achieve this, the scientists created two Escherichia coli bacterial populations. One group, the recipient bacteria, carried a disabled, inverted gene that made them unable to metabolise a simple sugar called galactose. The donor bacteria, in turn, had the ability to create a protein named Cre recombinase that could fix the inverted gene in the recipients. With a working version of that gene, the recipient bacteria could again feast on galactose. Only a cell that physically received the Cre protein could flip that gene back on.

"[Herman] went on vacation, and I was in the lab doing these experiments. I don't think we thought anything would come of it," recalls study lead author Alice X. Wen. But to the researchers' surprise, the bacteria in fact sent proteins to each other, albeit very slowly.

The team then found that exposure to antibiotics kicked the exchange into high gear, making the protein transfer rate jump roughly 4,000-fold. In nature, antibiotic stress splits bacteria into two camps. Most cells ramp up a membrane stress response and shed vesicles loaded with protein cargo, leaving themselves exposed to the antibiotics. The others go dormant, shutting down protein production and reproduction to survive the antibiotic onslaught. Herman suspects incoming vesicles deliver repair proteins that the dormant cells can no longer make themselves, such as a DNA polymerase to restart replication when the bombardment is over. This process even worked when the donor and recipient cells were different bacterial species.

The team does not yet know why stressed cells help their neighbours survive. Herman speculates that, besides working as a population survival mechanism, capturing a neighbour's protein could also let a cell sample what it has to offer — going through a microbial version of a free trial before committing to something more permanent, such as taking its DNA.

This study, which had multiple control groups to rule out other explanations, "is a very elegant way to demonstrate that there actually is protein transfer," says Laurence Van Melderen, a microbiologist at the Université Libre de Bruxelles in Belgium, who was not involved but co-authored an accompanying commentary in Science.

Scientists hope this mechanism's discovery will one day help stop bacteria from mutating to withstand antibiotics. "Persistence is the first step to resistance," Herman says. "If we could stop that, I think it would be very helpful in stopping the rise of antibiotic resistance."

Questions

Questions 1–5: TRUE / FALSE / NOT GIVEN

  1. Bacteria have been known to share DNA through horizontal gene transfer.
  2. The new study is the first to observe bacteria transferring proteins to each other via vesicles.
  3. The recipient bacteria in the experiment could already metabolise galactose.
  4. The protein transfer happened at the same rate whether antibiotics were present or not.
  5. The protein transfer only worked between bacteria of the same species.

Questions 6–10: Choose the correct letter, A, B, C or D.

  1. What are vesicles?

    • A. Specialised antibiotics
    • B. Tiny fluid-filled bubbles enclosed in fatty membranes
    • C. Types of bacterial genes
    • D. Repair proteins

  2. In the experiment, the Cre recombinase protein was needed to

    • A. produce antibiotics
    • B. fix the inverted gene so recipients could metabolise galactose
    • C. kill the donor bacteria
    • D. create new vesicles

  3. When antibiotics were present, the protein transfer rate

    • A. decreased slightly
    • B. stayed the same
    • C. increased about 4,000-fold
    • D. stopped completely

  4. What do dormant bacteria do when exposed to antibiotics?

    • A. They immediately die.
    • B. They shut down protein production and reproduction.
    • C. They attack other bacteria.
    • D. They leave the colony.

  5. According to Herman, understanding this protein transfer could help scientists

    • A. create stronger antibiotics
    • B. stop the rise of antibiotic resistance
    • C. grow bacteria faster
    • D. develop new food sources

Questions 11–13: Complete the sentences. Choose NO MORE THAN TWO WORDS.

  1. The study was published in the journal __________.
  2. The experiment used the bacterium __________ coli.
  3. Herman describes persistence as the first step to __________.

Answers

  1. TRUE
  2. TRUE
  3. FALSE (受体菌携带了失活的反向基因，不能代谢半乳糖)
  4. FALSE (抗生素使其加速约4000倍)
  5. FALSE (不同物种间也有效)
  6. B
  7. B
  8. C
  9. B
  10. B
  11. Science
  12. Escherichia
  13. resistance

Glossary

  • antibiotic /ˌæntibaɪˈɒtɪk/ n. 抗生素
  • vesicle /ˈvesɪkl/ n. 囊泡
  • horizontal gene transfer 水平基因转移
  • dormant /ˈdɔːmənt/ adj. 休眠的
  • metabolise /məˈtæbəlaɪz/ v. 代谢
  • galactose /ɡəˈlæktəʊs/ n. 半乳糖
  • polymerase /pəˈlɪmərəz/ n. 聚合酶
  • resistance /rɪˈzɪstəns/ n. 耐药性
  • microbiologist /ˌmaɪkrəʊbaɪˈɒlədʒɪst/ n. 微生物学家

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