Navigation Links
Scientists reveal the lifestyle evolution of wild marine bacteria
Date:5/22/2008

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; its 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 MITs 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.

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. Its only by determining bacterias ecological niche that scientists can classify them into populations. But microbes dont 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. Erics 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 clockthe rate at which a gene accumulates random mutations over timewas 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 its 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 microbes 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.


'/>"/>

Contact: Denise Brehm
brehm@mit.edu
617-253-8069
Massachusetts Institute of Technology, Department of Civil and Environmental Engineering
Source:Eurekalert  

Related biology news :

1. Scientists discover a molecular scaffold that guides connections between brain cells
2. Scientists paint viruses to track their fate in the body
3. Incense is psychoactive: Scientists identify the biology behind the ceremony
4. Scientists decipher fruit tree genome for the first time
5. Scientists discover small RNAs that regulate gene expression and protect the genome
6. Argonne scientists use lasers to align molecules
7. Too hot to handle! Scientists identify heat sensing regulator
8. Scientists dig deeper into the genetics of schizophrenia by evaluating microRNAs
9. Scientists endure Arctic for last campaign prior to CryoSat-2 launch
10. Scientists discover why plague is so lethal
11. UF scientists discover compound that could lead to new blood pressure drugs
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Scientists reveal the lifestyle evolution of wild marine bacteria
(Date:3/31/2016)... , March 31, 2016  Genomics firm Nabsys has ... CEO, Barrett Bready , M.D., who returned to ... the original technical leadership team, including Chief Technology Officer, ... Product Development, Steve Nurnberg and Vice President of Software ... the company. Dr. Bready served as CEO ...
(Date:3/21/2016)... Massachusetts , March 22, 2016 ... facial recognition with passcodes for superior security   ... ), a leading provider of secure digital communications services, ... their biometric technology and offer enterprise customers, particularly those ... secure facial recognition and voice authentication within a mobile ...
(Date:3/14/2016)... March 14, 2016 NXTD ) ("NXT-ID" ... commerce market, announces the airing of a new series of ... week of March 21 st .  The commercials will air ... popular Squawk on the Street show. --> NXTD ... growing mobile commerce market, announces the airing of a new ...
Breaking Biology News(10 mins):
(Date:5/23/2016)... ... ... for blood donations in South Texas and across the nation is growing. , But according ... donations are on the decline. In fact, donations across the country are at their lowest ... in the last four years alone. , There is no substitute for blood. , “We ...
(Date:5/23/2016)... ... May 23, 2016 , ... RoviSys, a leading independent ... Aurora, Ohio, has broken ground on a new building in Holly Springs, NC. ... this new location solidifies a commitment to business in the region. The new ...
(Date:5/20/2016)... ... , ... Korean researchers say Manumycin A triggers apoptosis, or natural cell death, ... the disease. Surviving Mesothelioma has just posted an article on the new study. ... their mesothelioma study on the fact the Manumycin A, a derivative of Streptomyces parvulus, ...
(Date:5/19/2016)... ... 19, 2016 , ... KCAS Bioanalytical and Biomarker Services, a ... Large Molecule & Biomarker Bioanalysis. , Dr. Siddiqui has more than 15 years ... preclinical and clinical safety programs. “We’ve seen significant demand for, and we are ...
Breaking Biology Technology: