Microbiology

[Poof]

Quote

The scale of life in the microbial world is such that amazing numbers become commonplace. These numbers can be sources of inspiration for those in the field and used to inspire awe in the next generation of microbiologists.

In science, numbers can become so complicated that their meaning becomes lost. To provide relevance to these unimaginable quantities, it is often useful to draw a comparison with other large (but more manageable) numbers, and nowhere is it more appropriate to do this than in the field of microbiology, in which mind-blowing numbers are to be found wherever one looks. Here, we draw together some awe-inspiring numbers that are found in microbiology, sourced from our followers on Twitter (@NatureRevMicro). The examples below are mostly based on 'back of the envelope' calculations and should therefore be viewed as they were intended: ballpark figures aiming to inspire. 

Astronomy is a field that is used to dealing with large numbers, but these can be dwarfed when compared with life on the microbial scale. For instance, if all the 1 × 10³¹ viruses on earth were laid end to end, they would stretch for 100 million light years. Furthermore, there are 100 million times as many bacteria in the oceans (13 × 10²⁸) as there are stars in the known universe which are considered to be more numerous than all the grains of beach sand on planet Earth. The rate of viral infection in the oceans stands at 1 × 10²³ infections per second, and these infections remove 20–40% of all bacterial cells each day. Moving onto dry land, the number of microorganisms in a teaspoon of soil (1 × 10⁹) is the same as the number of humans currently living in Africa. Even more amazingly, dental plaque is so densely packed that a gram will contain approximately 1 × 10¹¹ bacteria, roughly the same number of humans that have ever lived. Not quite so densely packed but impressive all the same, the bacteria present in the average human gut weigh about 1 kilogram, and a human adult will excrete their own weight in faecal bacteria each year. The number of genes contained within this gut flora outnumbers that contained within our own genome 150-fold, and even in our genome, 8% of the DNA is derived from remnants of viral genomes.

Microbiological numbers can also span enormous scales in space and time. For instance, the largest known contiguous fungal mycelium covered an area of 2,400 acres (9.7 square kilometres) at a site in eastern Oregon, USA. At the other end of the scale, there are 958,980 atoms in a single Simian virus 40 (SV40) virion. On the temporal scale, microorganisms can become dormant or form spores and survive for great lengths of time. For example, some viable bacteria extracted from amber were estimated to be 34,000–170,000 years old.

Perhaps the scariest numbers in microbiology relate to pathogenic microorganisms. Worldwide, 16 million people die from infectious disease every year, and many of these deaths are preventable. Approximately one in every 12 individuals, or 500 million people worldwide, is living with chronic viral hepatitis, and the estimated number of new chlamydial infections per year is approximately 50 million, more than the population of South Korea. The bacterium Clostridium botulinum produces a toxin so potent that 3 grams would be enough to kill the population of the United Kingdom and 400 grams would kill everyone on the planet.

In total, there are ∼1,400 known species of human pathogens (including viruses, bacteria, fungi, protozoa and helminths), and although this may seem like a large number, human pathogens account for much less than 1% of the total number of microbial species on the planet. On this point, ignoring questions about what actually constitutes a species, estimates for the total number of microbial species vary wildly, from as low as 120,000 to tens of millions and higher. Part of the reason for this large range is that we have only sequenced 1 × 10⁻²²% of the total DNA on Earth (although the Earth Microbiome Project should improve this dramatically to 1 × 10⁻²⁰% in the next 3 years). This means that the fraction of microbial diversity that we have sampled to date is effectively zero, a nice abstract entity to end on.

These examples barely scratch the surface of the wondrous world of microbiology, and we encourage readers to continue to help us build a list of the numbers that inspire interest in the field.

https://www.nature.com/articles/nrmicro2644

Edited July 23, 2020 by Poof

[new_disease]

I don’t know how true this is but I remember an anecdote from one of my biology professors saying that the amount of bacteria/microbes living inside us and on our skin outnumber our actual human cells so we should rethink what it means to be “us”. 

[lupin_bebop]

Okay......so.......pregnancy....is a disease then?

[Poof]

6 minutes ago, new_disease said:

I don’t know how true this is but I remember an anecdote from one of my biology professors saying that the amount of bacteria/microbes living inside us and on our skin outnumber our actual human cells so we should rethink what it means to be “us”. 

it's true but that's by quantity. Human cells are much bigger, so it's not like the majority of your weight is microbes. But like the article says, a not-insignificant portion is. A few pounds of microbes in the GI tract alone.

[Poof]

7 minutes ago, lupin_bebop said:

Okay......so.......pregnancy....is a disease then?

I knew a painter who played on that idea in his art. He said it's "the worst std"

[new_disease]

10 minutes ago, Poof said:

it's true but that's by quantity. Human cells are much bigger, so it's not like the majority of your weight is microbes. But like the article says, a not-insignificant portion is. A few pounds of microbes in the GI tract alone.

Just the thought of stuff like that makes me think maybe germophobes have the right idea  

[lupin_bebop]

10 minutes ago, Poof said:

I knew a painter who played on that idea in his art. He said it's "the worst std"

I mean, at its base definition, it’s correct. It’s a little erroneous, but sensible. 

[Poof]

9 hours ago, new_disease said:

Just the thought of stuff like that makes me think maybe germophobes have the right idea  

We need that stuff in us tho. The rona has me looking at germaphobes differently. I've never been one myself which is not surprising, but I might wear a mask whenever I fly from now on even after corona.

[Poof]

9 hours ago, lupin_bebop said:

I mean, at its base definition, it’s correct. It’s a little erroneous, but sensible. 

I think bc disease must be an "abnormal" condition you can argue either way as to whether pregnancy is a normal or abnormal process.

[RainyDayJizz#35]

4 minutes ago, Poof said:

We need that stuff in us tho. The rona has me looking at germaphobes differently. I've never been one myself which is not surprising, but I might wear a mask whenever I fly from now on even after corona.

You can even argue in both directions on that really easily. Bacteria exchange useful DNA all the time. When people get an e. Coli infection it's from ingesting a variety different from your native gut flora, if I remember right. The miniature world is a weird place, it's the kind of thing that makes me daydream about that perspective the men in black movies did. 

I don't think there's any way of really knowing if we're a bunch of subatomic particles living on an electron.

[Raptorpat]

10 hours ago, Poof said:

Even more amazingly, dental plaque is so densely packed that a gram will contain approximately 1 × 10¹¹ bacteria, roughly the same number of humans that have ever lived.

I've never felt the need to brush as much as I do right now

[Poof]

59 minutes ago, Raptorpat said:

I've never felt the need to brush as much as I do right now

send those cavity creeps packing

[Poof]

1 hour ago, GreatBallsOfJizz said:

You can even argue in both directions on that really easily. Bacteria exchange useful DNA all the time. When people get an e. Coli infection it's from ingesting a variety different from your native gut flora, if I remember right. The miniature world is a weird place, it's the kind of thing that makes me daydream about that perspective the men in black movies did. 

I don't think there's any way of really knowing if we're a bunch of subatomic particles living on an electron.

this is all just a dream anyway

[lupin_bebop]

1 hour ago, Poof said:

I think bc disease must be an "abnormal" condition you can argue either way as to whether pregnancy is a normal or abnormal process.

It's not the process of pregnancy that is abnormal. That's normal (and fun, in most cases).
It's the condition of pregnancy on the body. The fact it causes vomiting and other similar symptoms.

[new_disease]

2 hours ago, Poof said:

We need that stuff in us tho. The rona has me looking at germaphobes differently. I've never been one myself which is not surprising, but I might wear a mask whenever I fly from now on even after corona.

If I ever started going on planes I probably would too. Even if I ever start having a cold or something I'd probably mask up too to not spread that stuff either. 

[Poof]

18 minutes ago, new_disease said:

If I ever started going on planes I probably would too. Even if I ever start having a cold or something I'd probably mask up too to not spread that stuff either. 

yea. Like when I first started flying I thought about germs in the air a lot and would try and notice if I got sick in the couple weeks after the flight. I never really realized that I stopped doing that.