Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Biologists surprised to find parochial bacterial viruses

06.03.2008
Intriguing find reveals more mysteries from Mexico's Cuatro Cienegas

Biologists examining ecosystems similar to those that existed on Earth more than 3 billion years ago have made a surprising discovery: Viruses that infect bacteria are sometimes parochial and unrelated to their counterparts in other regions of the globe.

The finding, published online this week by the journal Nature, is surprising because bacteria are ubiquitous on Earth. They've been found from the upper reaches of the atmosphere to miles below the ocean floor. Because of their ubiquity, scientists have long believed bacteria to be cosmopolitan, having similar genetic histories across the globe. The same was also believed to be true for phages, the viruses that infect bacteria.

"The idea that things in the microbial world can have endemic properties is relatively new," said study co-author Janet Siefert, a Rice University computational biologist who has made a half-dozen trips to one of the study sites in Mexico's remote Cuatro Ciénegas valley. "People really weren't talking about it until about a decade ago, and we certainly didn't expect to find this when we began our work in Mexico."

... more about:
»Ciénegas »Cuatro »DNA »Database »metagenome »phage »pozas

Bacteria are the dominant forms of life on Earth. They helped shape the planet's land, oceans and atmosphere for 3 billion years before the first appearance of multicellular creatures. Siefert and several of her co-authors began traveling to Cuatro Ciénegas in Mexico's Chihuahuan Desert in 2004 to study cyanobacteria living in a network of more than 200 spring-fed pools, or “pozas.” Cuatro Ciénegas' pozas have been compared to the Galapagos Islands, except that their endemic species -- at least 70 species in the valley are found nowhere else on Earth -- are separated from the rest of the world by mountains and a sea of sand rather than an ocean.

The cyanobacteria in the pozas live communally, forming coral-like structures called "stromatolites," or microbialites, that are geologically identical to 3.5 billion-year-old fossils that are believed to be the oldest evidence of life on Earth.

"We had very little funding when we started going to Cuatro Ciénegas," Siefert said. "We were taking a shot in the dark to see if we could better understand the physical, chemical and geological context of the bacterial communities and the stromatolites."

The work drew interest and seed funding from NASA's astrobiology program, which hoped the work might provide important clues about the way early life might develop on other planets.

Siefert said biogeography -- the study of species’ biodiversity and distribution across time and space -- has only recently been possible for viruses, mainly due to advancements in software and other computer tools. New sequencing technologies made it possible to analyze and geographically map the genetic differences among viral genotypes in Cuatro Ciénegas and other locations. The new study's findings contrast with previous studies that found viruses are widely dispersed on Earth and share almost the same genotypes.

Stromatolite samples collected from two pozas in 2004 were examined by several co-authors in the research group of San Diego State University biologist Forest Rohwer, who has prepared the world's largest database of phage DNA. In the first step of the tests, researchers crushed small bits of the coral-like stromatolites and extracted DNA from the samples. The DNA from each sample was decoded and compiled into a database called a "metagenome." The metagenomes from the Mexican pozas were compared with each other and with metagenomes from stromatilites in Highborne Cay, Bahamas. Finally, all three of these metagenomes were compared with Rohwer's phage database and with several large gene-sequence databases, like GenBank.

"Taken together, these results prove that viruses in modern microbialites display the variability of distribution of organisms on our planet," Rohwer said. "It also suggests that they may be derived from an ancient, microbial community."

The analyses found that the phages in the Bahamas and in both Mexican pozas shared only about 5 percent of the same DNA sequences. Moreover, the analyses revealed that the Mexican phages appeared to have evolved from ancient, ocean-going relatives. Siefert said the finding is amazing given that Cuatro Ciénegas has been cut off from the ocean for about 100 million years, but it complements prior findings of marine genetic signatures in some of Cuatro Ciénegas' other endemic species.

"Over that length of time, we would expect the marine signature to get washed out of the genetic code," she said. "In fact, when we compared the phages from the pozas to oceanic phages, we found cases where the pozas' phages were more closely related to marine relatives than were some of the phages found in other oceans."

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

Further reports about: Ciénegas Cuatro DNA Database metagenome phage pozas

More articles from Life Sciences:

nachricht Seeing on the Quick: New Insights into Active Vision in the Brain
15.08.2018 | Eberhard Karls Universität Tübingen

nachricht New Approach to Treating Chronic Itch
15.08.2018 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Unraveling the nature of 'whistlers' from space in the lab

15.08.2018 | Physics and Astronomy

Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide

15.08.2018 | Earth Sciences

Early opaque universe linked to galaxy scarcity

15.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>