[ad_1]
In the laboratory of Professor George Fox at the University of Houston, scientists study the germs of the Earth that could contaminate other planets. Despite extreme decontamination efforts, the bacterial spores of the Earth still manage to make their way in space aboard spacecraft. Fox and his team are investigating how and why certain spores escape decontamination. Their research is published in BMC Microbiology.
For access to the ultra-hygienic cleanrooms at NASA's Goddard Space Flight Center in Greenbelt, Maryland, the largest clean room in the world, or at the Jet Propulsion Laboratory in Caltech, Calif., Employees go through a series of halls. One, with adhesive floor mats, traps the dirt on the shoes. Another, the size of an old phone booth, delivers a forced-air shower where dozens of air jets flush out dirt and debris. It is only after these sterilization measures that they can coat the bodies, headgear and other disinfected badges.
And yet, the bacteria survive and have been transported aboard the International Space Station and found on Mars Rover. The ability of bacteria to survive extreme conditions could lead to a process called "forward contamination".
"The search for life elsewhere is influenced by the possible transport of organisms from the Earth to organisms of interest to the solar system," said Fox, professor of biology and biochemistry and chemical and biomolecular engineering at the UH. Fox is no stranger to microbiology. In the 1970s, with his scientific colleague Carl Woese, he revolutionized the field by discovering that archaea are a separate area of life.
As in the case of natural selection, the cleaning process inside the clean rooms will eventually kill the weaker bacteria, while a stronger strain will fit and n '# 39; is not eliminated by cleaners.
"No matter what we do, some bacterial spores seem to find ways to escape decontamination," said Madhan Tirumalai, a postdoctoral biologist in Fox's lab. "I'm trying to understand what makes these spores so special at the genomic level and relate these characteristics to their ability to escape decontamination measures."
It starts with sequencing
The Fox team has studied non-pathogenic (non-pathogenic) bacteria that belong to the genus Bacillus and produce highly resistant spores. They have been isolated from clean rooms and spacecraft badembly facilities at the Jet Propulsion Laboratory.
They sequenced the complete genome of two peroxide- and radiation-resistant strains: B. safensis FO-36bT and B. pumilus SAFR-032. Then, they compared the genomes of these strains and those of another strain, B. safensis JPL-MERTA-8-2, with bacteria known to produce spores vulnerable to peroxide and radiation, such as strain B pumilus ATCC7061T. The B. safensis strain JPL-MERTA-8-2 was isolated from the Mars Odyssey spacecraft and badociated Jet Propulsion Laboratory facilities and was also found on the Mars Explorer Rover (MER) prior to launch in 2004.
"The genome plan gave us basic clues as to what the body could house," said Tirumalai. By comparing the shots of the four strains, they found 10 unique FO-36b genes, which are not found in any other organism (including other Bacillus strains). These are 10 genes whose functions are unknown – or 10 suspects of why the B. safensis FO-36bT spores are resistant to peroxide and radiation, although it is not immediately obvious that the presence or presence of the fungi is a problem. the absence of a specific gene or a combination of genes is responsible for the observed resistance variations.
"It is quite possible that distinctions in gene regulation may alter the expression levels of key proteins, thereby changing the body's resistance properties without gain or loss of a particular gene." These are potential genes of interest for spore resistance of this strain. "Tirumalai said.
In fact, four of these genes are found on the phage elements of the bacterial strain. Phage, short for bacteriophage, is a virus that infects bacteria. Phage are major facilitators for gene transfer between microbes.
[ad_2]
Source link
