Rare bacterial strain isolated and sequenced
The new bacterial strain belongs to the group Candidatus phylum
Dependentiae, a group of organisms that can only grow inside other cells
Date:
February 17, 2022
Source:
Tokyo University of Science
Summary:
Certain types of bacteria are unable to survive and thrive outside
host organisms. This makes their isolation and identification
technically challenging. Recently, a researcher successfully
isolated a new bacterial strain of the candidate bacterial group,
Candidatus phylum Dependentiae, from a pond.
FULL STORY ==========================================================================
The development of the field of metagenomics -- the study of genetic
material from environmental samples -- has revolutionized how we observe
and discover new species. Many bacteria cannot be independently cultivated
in the lab.
Sometimes this is because the medium they are grown in is not suitable, sometimes it is because these bacteria thrive only in multispecies
communities (such as many bacteria in our gut!) and sometimes this is
because they can only grow in relation to another larger organism. A
group of bacteria belonging to the final category are Candidatus phylum Dependentiae. Not much is known about this group because thus far, only
three strains belonging to it have been isolated. But in a recent study, published in Microbiology Resource Announcements, Professor Masaharu
Takemura from Tokyo University of Science (TUS) has succeeded in isolating
the fourth such strain -- Noda2021.
========================================================================== "Initially we sampled Risoukai Park in the Noda Campus of TUS with the
aim of isolating a giant virus by screening it using a common laboratory
host 'Vermamoeba vermiformis.' However, in the process of doing so we accidentally discovered this rare bacterium that also infects Vermamoeba,"
says Dr.
Takemura.
To isolate the new strain, Dr. Takemura first cultured a sample
obtained from the pond in Risoukai Park and then added it to a culture
of Vermamoeba. After growing the Vermamoeba for a few days, he extracted Noda2021 from this and then performed an analysis of its genetic material.
"We found that the Noda2021 strain consists of 1,222,284 base pairs with approximately 38.3% guanine and cytosine (GC) content and 1,287 genes. We
then performed a 16S rRNA molecular phylogenetic analysis of the strain
and found that it is relatively close to one of the other Candidatus
phylum Dependentiae strains isolated so far, 'Vermiphilus pyriformis,'" explains Dr. Takemura. He also examined the infected Vermamoeba cells
under an electron microscope and found that Noda2021 sometimes exhibited
a connected cellular structure within its host cells.
"This discovery is evidence that the pond in the Noda campus
is microbiologically diverse and ecologically exciting," says
Dr. Takemura. This is also the first time such a strain has been isolated
in Japan.
The isolation of this new strain of Candidatus phylum Dependentiae is sure
to further our understanding of this curious bacterial group. According
to Dr.
Takemura, "This bacterium is located in the border
region between giant viruses and microbacteria, so we
expect it to provide some useful and unique information
on the origin and ecological position of both these groups." ========================================================================== Story Source: Materials provided by Tokyo_University_of_Science. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Masaharu Takemura. Genome Sequence of a New " Candidatus " Phylum
"Dependentiae" Isolate from Chiba, Japan. Microbiology Resource
Announcements, 2022; 11 (2) DOI: 10.1128/mra.01123-21 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/02/220217102039.htm
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