Antibiotics, a vital tool for fighting infections, were originally products of nature—the first antibiotic was serendipitously discovered in mold contaminating a bacterial culture. As antibiotic resistance becomes an increasingly serious threat, scientists are attempting to wring another type of pathogen-fighting drug from the wild: antimicrobial peptides.

Antimicrobial peptides, or AMPs, are found in almost every type of organism—even bacteria themselves. They’re part of the innate immune system, which helps to ward off many classes of intruders. Although some researchers are attempting to develop AMPs into drugs, not everyone is enthusiastic about the strategy. If a pathogen developed resistance to AMP-derived drugs, it might also become resistant to the host’s natural AMPs. This could have disastrous consequences for the host population. And fears of resistance may not be unfounded: AMP-resistant bacteria have already been bred in the lab.

Until now, the mutations responsible for AMP resistance have barely been studied. In a step toward finding and characterizing them, an article in the June issue of G3 reports a number of candidate genes involved in resistance to multiple classes of AMPs. To find the genes, the researchers treated Staphylococcus aureus with different AMPs at levels that allowed resistant strains to evolve. By comparing the genomes of the resistant strains to the original S. aureus genome, they found several genes that were mutated in the AMP-resistant bacteria. And supporting the notion that these mutations were involved in AMP resistance, the colonies resistant to a given AMP consistently carried mutations affecting the same gene or genes.

While compelling, this doesn’t prove that these mutations are truly responsible for AMP resistance. To determine whether or not the mutations were responsible for resistance, the researchers selected strains from the Nebraska Transposon Mutant Library with mutations that impaired the candidate genes. By treating these strains with AMPs, they found that the mutant strains were indeed altered in their susceptibility to their corresponding AMPs. This means it’s very likely that the genes they found are directly involved in the evolution of AMP resistance. As well as enabling us to predict how pathogens might gain resistance to any AMP-derived therapies, further research on these resistance-associated genes may also help us understand how AMPs function, providing insight into this widely-used component of innate immunity.

CITATION:

Johnston, P.; Dobson, A.; Rolff, J. Genomic Signatures of Experimental Adaptation to Antimicrobial Peptides in Staphylococcus aureus.
G3, 6(6), 1535-1539.
DOI: 10.1534/g3.115.023622
http://www.g3journal.org/content/6/6/1535.long

, , ,

Nicole Haloupek is a freelance science writer and a recent graduate of UC Berkeley's molecular and cell biology PhD program.

View all posts by Nicole Haloupek »

Read more in

  • Ed Grell at his dissecting microscope using ether to anesthetize his flies.

    In Memoriam: Ellsworth Herman Grell (1932–2023), a pioneer of Drosophila genome engineering and annotation

    Ellsworth (Ed) Grell blessed the Drosophila community through three enduring legacies: as a pioneer of chromosome mechanics, as a primary organizer and synthesizer of genetic knowledge in Drosophila, and as a graceful mentor to those fortunate to have known him personally. Ed grew up in rural Nebraska, completed his undergraduate studies at Iowa State, and…

  • Congratulations to the #Fungal24 Poster Award winners!

    We are pleased to announce the recipients of the GSA Poster Awards for posters presented at the 32nd Fungal Genetics Conference! Undergraduate and graduate student members of GSA were eligible for the awards, and a hard-working team of judges made the determinations. Congratulations to all! Felicia Ebot Ojong, The University of Georgia My research is focused…

  • Poster presentation tips for TAGC 2024

    You’ve been selected to present a poster at The Allied Genetics Conference 2024 in March—you’ve celebrated, made plans to attend, now what? This is an exciting opportunity to showcase your research and engage with fellow members of the genetics community, so you want to make sure you’re prepared. We wanted to offer you some tips…

  • Maximize your TAGC 2024 experience 

    A guide to all that National Harbor & DC have to offer Are you joining us for The Allied Genetics Conference 2024 in March? Make the most of your #TAGC24 experience in National Harbor! We know the science will keep you busy, but you deserve to unwind and have some fun, so we’ve curated a…

  • Early Career Leadership Spotlight: Sarah Petrosky

    We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Sarah PetroskyMultimedia SubcommitteeUniversity of Pittsburgh Research Interest I am interested in understanding adaptation that has been happening recently in populations by dissecting the ways that genes underlying an adaptation…

  • TAGC 2024 Early Career Award Winners

    GSA is pleased to announce the winners of the early career awards presented at The Allied Genetics Conference 2024. These awards are specific to particular TAGC communities and recognize early career scientists’ outstanding work on their respective research organisms. The awardees will present their talks in keynote sessions at TAGC 2024.  Don’t miss the opportunity…

  • Preeminent geneticists recognized with revamped GSA Awards

    In 2022, GSA’s Board of Directors launched an audit to review the five major awards conferred by the Society. Today, we are thrilled to announce the recipients of the reimagined GSA Awards, including the new Genetics Society of America Early Career Medal. The scientists honored this year are recognized by their peers for their outstanding…

  • Fly Board funds outreach programs to spread the word about Drosophila research

    In 2020, the Fly Board voted to use part of its reserve fund to support efforts to increase trainee participation as well as equity and diversity in the Drosophila community. An awards committee decides how the money will be spent each year, and from 2020–2022, the committee posted a very broad call for applications from…

  • New members of the GSA Board of Directors: 2024–2026

    We are pleased to announce the election of four new leaders to the GSA Board of Directors: 2024 Vice President/2025 President Brenda Andrews Professor, University of Toronto It’s an honor to continue my association with the Society by serving as Vice President of the Board of Directors. I have broad knowledge of the ongoing activities…

  • A rose-ringed parakeet, one of three parrot species used in the study.

    Parrot plumage study aids breeders and endangered natural populations

    Yellow coloration is maladaptive in the wild but prized by breeders. People have long been fascinated with birds, which exhibit one of the widest ranges of coloration among vertebrates. Parrots, in particular, have captivated humans by their ability to mimic human speech and spectacular plumage. Brightly colored feathers are used primarily to attract mates, intimidate…

  • Early Career Leadership Spotlight: Sarah Gilmour

    We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Sarah GilmourMultimedia SubcommitteeStowers Institute for Medical Research Research Interest Questions of evolution have always fascinated me. I am extremely fortunate to be starting out my research career in a…