Why do we love microbes? And how do microbiologists
choose their favorite microbe? This is what I'll
explore in today's episode. Hello, I'm Lori
Daane, and welcome to My Favorite Microbe, a podcast
where we ask guests one deceptively simple question.
What's your favorite microbe and why? As you
listen today, I invite you to think about your
own favorite microbe. Or if you're not a microbiologist,
maybe simply the organism that first made you
realize the microbial world is amazing. When
I released the trailer, friends immediately asked,
what's your favorite microbe? That wasn't supposed
to happen. I planned to ask guests, not answer
it myself. As a microbial ecologist, I usually
think about communities rather than individual
organisms. Asking me to choose is a little like
asking me to choose my favorite color or my favorite
band. The answer changes over time. The more
I thought about it, the more I realized this
episode isn't really about naming my favorite
microbe. It's about why microbiologists become
attached to certain organisms. So today I'll
walk you through how I made my choice and why
it became far more emotional than I expected.
If I think about finding my favorite, The first
thing I ask myself is, what makes it memorable?
Some microbiologists love medically important
organisms. These are the villains or bad guys
of microbiology. Think Yersinia pestis in the
Black Death or Clostridium tetani causing tetanus.
Here's one of my favorite historical microbiology
stories. John Roebling, the original designer
of the Brooklyn Bridge, actually died of tetanus
before construction began after crushing his
foot in a ferry accident. His son, Washington,
became chief engineer and was credited with completing
the bridge, when in reality it was most likely
completed by Washington's wife, Emily. I first
learned that story from David McCullough's wonderful
book, The Great Bridge. And by the way, it's
probably worth asking yourself, when was your
last tetanus shot? Historical importance could
certainly make a microbe memorable, but that's
not how I chose mine. I've always been fascinated
by microbes that live where nothing else should
survive, the extremophiles. I think I've watched
every documentary on deep -sea hydrothermal vents.
From an evolutionary standpoint, Extremophiles
are especially fascinating because they help
us understand the limits of life. Extremophiles
are also of interest because of their potential
for bioremediation of environments made hazardous
to humans due to pollution or contamination.
Leave it to a microbe to adapt to exploit an
environment. True story. When I was in grad school
taking, I think it was a behavioral ecology class,
The professor, who was an ornithologist, said,
can you imagine how terrible it would be if there
was a microorganism that could eat gasoline?
I looked around thinking, is this guy joking?
I think I was the only microbial ecologist in
the class, and I was too insecure at the time
to speak up about how microbial populations evolve
as you move away from the most heavily contaminated
part of a pollution plume. In fact, scientists
go to these environments to collect samples specifically
looking for extreme microbial metabolic diversity.
So perhaps my favorite would be an extremophile.
That would make sense, but it isn't. To understand
my actual choice, we need to go back to my first
postdoc at Rutgers University. I joined Dr. Max
Häggblom's laboratory in the late 1990s. At the
time, Max was a young, untenured assistant professor
with a couple of graduate students and three
postdocs. We called ourselves the Bloomer Lab,
and we were the original bloomers. One of my
first tasks was to collect sediment and salt
marsh plants from a somewhat contaminated area
in New Jersey. I remember that it was low tide,
and I had to use two pieces of plywood to get
out a bit to grab plants and sludge. It looked
like black mayonnaise, and without the plywood,
I might have sunk into the sludge and been unable
to get back out. I remember the smell to this
day, and looking at the surface of the sediment,
you could see what looked like gas or fuel swirled
within the water. Let's just say, lighting a
match would not have been a good idea. I wasn't
there alone. Monica, a postdoc in another lab,
came with me. She was standing on a bridge that
spanned the area where I was sampling. and at
one point, I looked up and saw her talking to
two police officers. I couldn't hear what they
were talking about, but at one point, one of
the police officers yelled out to me to make
sure to let them know if I find a body or a gun.
It was New Jersey. At the time, it just felt
like another day of fieldwork. Looking back,
it became one of those stories scientists tell
for the rest of their careers. Back in the lab,
I used those sediment and root -associated samples
to isolate spore -forming bacteria capable of
degrading polyaromatic hydrocarbons, the pollutants
we were studying. One group turned out to represent
a previously undescribed species of Penibacillus.
For a microbiologist, helping discover and describe
a new species is a little like an astronomer
helping identify a new star. Now I should mention
that Max's lab benefited from the involvement
of an important adjunct professor, Dr. Norberto
Palleroni, who passed away in 2018 at age 96.
When I was at Rutgers, he was about 75 and still
came into the lab to mentor students. So I had
the great fun and honor of helping to characterize
and describe a new species which Norberto helped
us name, Penibacillus naphthalenovorans. which
means naphthalene devouring. I'm extremely proud
to have published this work with Norberto Palleroni.
Now with that said, Penibacillus naphthalenovorans
is not my favorite microbe. For those who may
not know, Dr. Palleroni was an internationally
recognized authority in bacterial taxonomy, particularly
the genus Pseudomonas. In fact, people called
him the father of pseudomonads. I recall being
at a microbiology conference where Norberto attended,
and people were lining up to meet him and exchange
stories about taxonomy and pseudomonas. In preparing
for this episode, I found two printed publications
that Norberto gave me. On a paper about prokaryotic
diversity and the importance of culturing, he
wrote, To Dear Lori Daane, Affectionately, Norberto.
The second was a chapter titled, Introduction
to the Aerobic Pseudomonads. He gave it to me
after we characterized a new species together.
This time he wrote, To my friend and colleague,
Lori. Affectionately, Norberto. It's been almost
30 years and I still have both papers. I'll put
a link to the published memoriam in the show
notes so you can learn more about this amazing
microbiologist. Now let's get back to choosing
my favorite. So it isn't an extremophile, it
isn't a pathogen with a dramatic history, and
surprisingly, it isn't even the organism I helped
describe as a new species. I chose Stenotrophomonas
maltophilia. Say it with me. Stenotrophomonas
maltophilia. It sounds musical, and it just rolls
off the tongue. Interestingly enough, in 1993,
Norberto and J .F. Bradbury introduced Stenotrophomonas
as a new bacterial genus, with Stenotrophomonas
maltophilia. as the single species. Before listing
three fast facts, let's break down the name.
Steno means narrow, trophos means one who feeds,
and monos means a single unit. When you put it
together, the genus roughly means a unit feeding
on few substrates. Maltophilia means malt -loving.
So there you have it, the narrow feeder that
loves malt. Now some fast facts. It has had an
identity crisis. It was first found in a pleural
effusion in 1943 and given the name Bacterium
bookeri. Over the decades, it moved from bacterium
to Pseudomonas, then Xanthomonas, and finally
Stenotrophomonas in 1993. It's ubiquitous, widely
distributed in water, soil, and plant -associated
environments, and it's particularly good at attaching
to surfaces and forming biofilms. It has emerged
as an opportunistic human pathogen and can be
multidrug -resistant, making it difficult to
treat. Bonus fact, a close relative Stenotrophomonas
rhizophila has been proposed as a safer alternative
for biotechnological applications. Looking back
at my process, I thought I chose this organism
because I liked the sound of its name. But when
you hear Stenotrophomonas maltophilia., you may
simply hear the name of a bacterium. I hear Norberto
Palleroni. I remember Max Häggblom's lab. the
original bloomers, and the excitement of being
a young scientist doing what I loved. That is
why I think microbiologists often choose their
favorite through emotional attachment. It isn't
necessarily about medical importance, metabolic
diversity, or even how it looks on an agar plate.
It is about connecting to a place and time and
the people in our lives. I thought choosing a
favorite microbe would be impossible, but in
the end, I realized my favorite wasn't really
about the organism. Maybe that's true for all
microbiologists. Maybe every favorite microbe
is really a story about a mentor or a discovery
or a turning point in someone's life. That's
exactly what I hope to find as I begin asking
guests one simple question. What's your favorite
microbe? I'm Lori Daane, and thank you for listening.
You can send me your favorite microbe or suggest
a future guest at myfavoritemicrobe at gmail
.com. Please subscribe and like and join me next
time for another favorite microbe.