Featured Research

from universities, journals, and other organizations

Surviving attack of killer microbes

Date:
August 19, 2014
Source:
Okinawa Institute of Science and Technology - OIST
Summary:
The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules of the game. This unusual virus turns some individual microbes into killers. That is, when these killer microbes encounter any other microbe that is competing with them for resources, they kill that microbe on the spot.

Spear-shaped viruses attack a spherical microbe. The microbe is a dead ARMAN, and the viruses represent at least two different types of virus. This image is a slice from a 3D cryo-ET reconstruction of an acid mine drainage biofilm region produced by Dr. Luis R. Comolli, guest editor of Frontiers in Microbiology.
Credit: Image courtesy of Okinawa Institute of Science and Technology - OIST

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules of the game. This unusual virus turns some individual microbes into killers. That is, when these killer microbes encounter any other microbe that is competing with them for resources, they kill that microbe on the spot.

One would imagine that eventually, only killer microbes would remain, because all non-killer, or sensitive microbes, would die. But this is not the case. In both wild and in-vitro experiments, the sensitive microbes persist. This question piqued the interest of mathematician Robert Sinclair, a professor at Okinawa Institute of Science and Technology Graduate University who heads the Mathematical Biology unit.

Sinclair first heard about killer microbes from Prof. Alexander Mikheyev in the OIST Ecology and Evolution unit. He credits the design of the university for fostering interactions between researchers. "I would never have known about killer microbes if I had been at a normal university," explained Sinclair.

Mikheyev, who frequently uses baker's yeast as his microbial study subject, had been following emerging research on how specific viruses were turning individual yeast cells into killers. "You can look at the question more broadly," explained Mikheyev, "as 'What happens when you have different strategies for surviving?' We cannot see most of the microbial world, and it is run by different laws than our own."

In the past, researchers have shown that producing more offspring was the sensitive microbes' key to survival. If the sensitive microbes had a higher reproduction rate, or reproduced far more offspring than the killer microbes, there was no way the killer microbes could kill them all. But no one could assign a number, to show exactly how much more prolific the sensitive microbes would need to be.

As a mathematician, Sinclair saw the question differently: in terms of infinity. "There are many infinities," said Sinclair, "and they're all quite different." In this case, he wondered if only an infinitesimally small change in reproduction rate would make the difference between sensitive microbes' persistence and death. Instead of modeling hundreds of scenarios, each with a slightly smaller difference in reproduction rate, he would set up a proof and find out.

Sinclair wrote equations somewhat like the logistic growth model, a standard theory that represents population growth. Then he analyzed the equation to determine just how many more offspring the sensitive strain needed to reproduce in order to survive. He found that one doesn't need to measure the reproduction rate between sensitives and killers. As long as the sensitive strain has the higher reproduction rate, it can coexist with killer microbes. His result was published July 14, 2014 in Frontiers in Microbiology.

In addition to solving the killer microbe conundrum, Sinclair's analysis is unusual because it discusses the infinitesimally small. This idea is typically restricted to pure mathematics, because it is hard to model infinity. "Going to infinity presents trouble," Sinclair explained. "There are things that can happen that you do not expect." Applying the infinitesimally small to a real world situation bridges the gap between pure mathematics and applied mathematics. "It's not that these topics are so monstrously different," said Sinclair. "I would like to break this artificial boundary pure mathematics and applied mathematics."


Story Source:

The above story is based on materials provided by Okinawa Institute of Science and Technology - OIST. The original article was written by Poncie Rutsch. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert M. Sinclair. Persistence in the shadow of killers. Frontiers in Microbiology, 2014; 5 DOI: 10.3389/fmicb.2014.00342

Cite This Page:

Okinawa Institute of Science and Technology - OIST. "Surviving attack of killer microbes." ScienceDaily. ScienceDaily, 19 August 2014. <www.sciencedaily.com/releases/2014/08/140819083205.htm>.
Okinawa Institute of Science and Technology - OIST. (2014, August 19). Surviving attack of killer microbes. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2014/08/140819083205.htm
Okinawa Institute of Science and Technology - OIST. "Surviving attack of killer microbes." ScienceDaily. www.sciencedaily.com/releases/2014/08/140819083205.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins