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Halo-Ed: Extreme Microbiology and
Astrobiology Education and Outreach |
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Introduction Extremophilic microorganisms offer an ideal way to teach and
learn about astrobiology,
life in extreme environments on Earth, and fundamental concepts of
microbiology and molecular genetics. We have developed Halobacterium sp. NRC-1, a salt-loving member of the Domain
Archaea, which we use as a model organism for research in our laboratory, for
extreme microbiology, climate
change, and astrobiology education, including the Purple Earth
Hypothesis (see also What
purple can tell us about life on other planets). NRC-1 has many interesting features and
has inspired countless students to research and explore them further and
share their findings for the general public e.g. Gas
Vesicle Nanoparticles (GVNPs)
that allow cells to float, and give NRC-1 their distinctive pink color and
are extensively being explored for use in biomedicine and biotechnology
applications, including for vaccines and targeted drug delivery (see student report). Gas Vesicle Nanoparticles (GVNPs, formerly known as Gas Vesicles
or GVs) are phase-bright organelles, consisting of a membrane made only of
protein, surrounding a gas-filled space, which promote movement of cells
vertically in the water column, giving the cells buoyancy. They were first
described by Winogradsky in 1888
in cyanobacteria, and in Haloarchaea in the early
1900s. The first two gvp genes,
gvpA and C, were identified in Calothrix PCC 7601 by Tandeau de Marsac.
Professor
DasSarma, at the Pasteur Institute, used the Calothrix gvpA for heterologous DNA probing of Halobacterium sp. NRC-1 (where the
organelles refract light and make the cell colonies appear pink – see
colonies in JB cover below, as opposed to red for those not expressing them),
and showed that the gene was located on the pNRC100 minichromosome. Next his laboratory identified all the gvp genes as well as, through
knock outs, which 10
genes were essential for wild type GVNP production. Subsequently, the lab
developed a number of patents
and a company
for production of GVNPs for biotechnological
as well as biomedical, including vaccine
and drug-delivery, applications. This is made particularly easy, due to
the development of a genetic
system in NRC-1 where they are easily isolated by flotation after cell
disruption. A recent development of a hybrid
expression system has further enhanced the system. Both inquiry-based educational kits for the classroom, The Model Microbe, and a companion genomic database, HaloWeb, serve as resources for students
and teachers. In addition, MolGenT, an electronic
tutor illustrating concepts of life on Earth, is available to the community.
Upon completion of the MolGenT Test, participants can obtain a certificate. Activities for younger students are also
available. These resources are ideal for understanding principles of extreme
microbiology, the new field of astrobiology, and are suitable for students of
all ages.
Covers highlighting Haloarchaeal research from our laboratory Our hands-on laboratory modules available through Carolina Biological
Supply Co. are called Microbiology I, Life in Extreme
Environments, and Antibiotics in Action. Please note, to order pre-poured
plates for growing the microbes, you will need to call Carolina and
request the following (currently unlisted) item number: 821536. We are
working on getting this listed in the near future! If you are looking for pre-made broth, they carry that as
item#: 821449
and prepared media containing agar for
pouring plates (with a demonstration video that can be seen here)
as item#: 775950.
In addition to the programmed exercises, students can explore
research questions, many of which are currently engaging scientists in
various fields, from microbiology to astrobiology. Students are encouraged to
ask outstanding questions like 'How did life originate on Earth?', 'What
conditions limit life on Earth?' and 'Is there life elsewhere in the
universe?'. The exercises have been recognized and certified by the AP Board,
see The American Biology
Teacher. All of our exercises are based on the extremely halophilic
microbe Halobacterium NRC-1, which
has the remarkable ability to survive under multiple extreme conditions.
Moreover, the nearly saturating concentration of salts makes its growth
medium safer by inhibiting most harmful contaminants. The microbe is also
colorful, easy to culture, grows well at standard temperatures, and is widely
distributed in nature. It is also genetically tractable and the genome has
been completely sequenced. NRC-1 has several applications in biotechnology
and medicine. Students and teachers may also be interested in talks and
webinars from the DasSarma Lab: Ancient Pink and Purple
Microbes for Research and Education (18 minutes) Evolution and Survival
of Ancient Microbes: Deep Underground, Above the Atmosphere, and Possibly on
Mars (47 minutes) Earth's Extremophiles and
the Search for Life on Mars (36 minutes) Diversity of Archaeal
Photo Pigments and Implications for Biosignatures (13 minutes) Extreme Biotech:
Understanding Extremophile Biology to Impact Human Health (27 minutes) Professor Shiladitya DasSarma's tribute lecture for Prof Khorana on his
birth centenary in January 2022 (53 minutes) Ancient microbes as models
for Astrobiology: Polyextremophilic capabilities and early evolution of
halophilic Archaea (90 minutes) Haloarchaea: Potential for space travel
(22 minutes) Ancient
Pink and Purple Microbes for Research and Education: Making Microbiology
Manageable (~10 minutes)
Map of the
World, showing the countries from which the 100+ Haloarchaea with publically
available complete genomes and proteomes are available (Purple color). @
Priya DasSarma, Created and reproduced with
permission, using mapchart.net. For
Questions and Suggestions, contact the Halo-Ed Team |
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To
support this effort, please click here,
and follow these steps: 1.
find “Make your selection (s)” 2.
under “Area of Support” click on Other (please
specify)“ 3.
on the new page, click on “+ Add Another” 4.
now select “Other (please specify)” 5.
go to “Make your selection(s)” 6.
scroll down to: "HERD Fund (SOM)" and
direct your donation there Thank you. Your support means so much to us and will fund much
needed infrastructure and expansion work for our free to all resources! |
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Copyright ©
Shiladitya DasSarma & Priya DasSarma |
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