Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists reveal the lifestyle evolution of wild marine bacteria

27.05.2008
Free-floating cells share resources with their attached relatives

Marine bacteria in the wild organize into professions or lifestyle groups that partition many resources rather than competing for them, so that microbes with one lifestyle, such as free-floating cells, flourish in proximity with closely related microbes that may spend life attached to zooplankton or algae.

This new information about microbial groups and the methodology behind it could change the way scientists approach the classification of microbes by making it possible to determine on a large scale, relatively speaking, the genetic basis for ecological niches. Microbes drive almost all chemical reactions in the ocean; it’s important to identify the specific professions held by different groups.

“This is the first method to accurately differentiate the ecological niche or profession among large groups of microbes in the ocean,” said Professor Martin Polz, a microbiologist in MIT’s Department of Civil and Environmental Engineering. He and colleague Professor Eric Alm, a computational biologist, published a paper describing their research in the May 23 issue of Science.

... more about:
»Genetic »Polz »bacteria »ecological »habitat »microbes »niche

The nature of reproduction in microbes makes it impossible to define populations based on the ability of individuals within a species to share genes, as we do with larger animals. It’s only by determining bacteria’s ecological niche that scientists can classify them into populations. But microbes don’t live in natural population groups when cultured in a lab. So scientists must catch bacteria in the wild, then examine them genetically to determine their lifestyle.

“Most methods in use either over or underestimate greatly the number of microbial populations in a sample, leading either to a confusing array of populations, or a few large, but extremely diverse groups,” said Polz. “Eric’s method takes genetic information and groups the microbes into genetically distinct populations based on their preference for different habitats. Although this sounds like a simple problem, it is exceedingly difficult with microbes, because we have no species concept that would allow us to identify the genetic structure expected for populations. Microbial habitats differ on such small scales that they are invisible to us.”

Polz and former graduate student Dana Hunt, now a postdoctoral researcher at the University of Hawaii, created a large and accurate genetic data set by isolating and identifying over 1,000 strains of vibrio bacteria from a sample of eight liters of seawater gathered near Plum Island, Mass., in the spring and fall. To achieve accuracy in their identification of strains, they selected a gene whose molecular clock—the rate at which a gene accumulates random mutations over time—was well-suited to the task.

“The trick in many ways is choosing a gene that has a molecular clock that ticks at the right rate,” said Polz. “In particular, if it’s too slow, you might lump organisms into a single group that you would actually like to differentiate. We chose a gene that accumulates mutations fairly fast and thus allowed us to differentiate closely related groups of individuals and map the ecological data we collected onto their family tree.”

Alm and graduate student Lawrence David wrote an algorithm to make a conservative estimate of the minimum number of different habitats occupied by the vibrios (whether they live on small or large particles and thrive in the cool or warm months, etc.). They then combined information about habitat with phylogeny (the evolutionary history of groups of genes), and apportioned the original strains into 25 distinct populations and mapped their habitats back to a common ancestor, showing when and how each group diverged from the ancestral lifestyle.

“What is really new about our approach is that we were able to combine both molecular data (DNA sequences) with ecological data in a single mathematical framework,” said Alm. “This allowed us to solve the inverse problem of taking samples of organisms from different environments and figuring out their underlying habitats. In essence, we modeled the evolution of a microbe’s lifestyle over millions of years.”

One splendid example of the difficulty of applying the term “species” to a single-celled creature: 17 of those 25 populations are called V. splendidus, a name that was previously assigned to them based on classical taxonomic techniques. Alm and Polz can see now that V. splendidus has differentiated into several ecological populations.

Alm and Polz believe they caught at least one of those V. splendidus populations in the act of switching from one ecological niche (thriving on zooplankton) toward a new niche (attaching to small organic particles). Of course, this process takes millions of years, so the current population of scientists may never know for certain.

Denise Brehm | EurekAlert!
Further information:
http://www.mit.edu

Further reports about: Genetic Polz bacteria ecological habitat microbes niche

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>