Wednesday, 24 February 2016

Has A New Form Of Microbial Life Been Discovered?

The human intestines are home to trillions of microorganisms (many bacteria, some fungi, and by-products – collectively known as the microbiome). Several strands of research are showing how the numbers and types of certain bacteria are important for the regulation of immune function and how disruption can lead to autoimmune diseases.
New research suggests we may need to re-consider how we track and categorize the microorganisms within this ecosystem. Scientists at the Pierre and Marie Curie University in Paris, France are looking at how to redefine the classification of bacteria found within the colon. This is through examining 86 gene families using next-generation sequencing methods.
The findings suggest the current three categories for microbial life – bacteria, archaea, and eukaryotes (which includes fungi and single-celled parasitic animals) – could be insufficient. In short, a case could be made for a fourth type of microbial life. These microbes are lurking in what is termed “microbial dark matter.”
According to New Scientist magazine, the research group found 230,000 DNA sequences that are related to known sequences in those 86 gene families. This analysis found “an additional 80,000 stretches of microbial DNA that belonged in the 86 gene families.”
There is a lot of work to do, and evidence gathering to complete, before a firm case is made for a fourth domain and before this becomes universally accepted in the microbiology world. This includes isolating and culturing the organisms. Finding a means to do this, given most microbes are unculturable, will be difficult.
The researchers have put forward the notion in the journal Biology Direct. The research paper is headed “Highly divergent ancient gene families in metagenomic samples are compatible with additional divisions of life.”



Posted by Dr. Tim Sandle

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