Recently, intense interest in halophiles has come from the perspective of our search for extraterrestrial life (ETL), or the search for life on other planets. Many planets have been discovered in other solar systems in the past 10 years. Are there life-forms on these planets? Where are they? What are they like? Halophiles are perfect candidates for life on our closest neighboring planet, Mars. They can withstand radiation, such as ultraviolet and even gamma radiation, desiccation and extreme conditions found on Mars.

In this exercise, called Life in an Extreme Environment, students use salt crystals with entrapped brine inclusions containing live Halobacterium sp. NRC-1 to grow a liquid culture. Once grown, students observe the phase-bright gas vesicle inclusions, which enable the cells to float and give the liquid culture its opaque appearance. They can also see pink coloration due to the presence of carotenoids, light absorbing molecules that protect the cells against damaging radiation, and purple hue due to bacteriorhodopsin, a pigment in the cell membrane used to obtain energy from light in an alternative fashion to that of photosynthesis. These features allow these cells to survive conditions that are lethal to most common microorganisms. For more information, see:

Life in an Extreme Environment

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As a companion to this website, we have developed a comprehensive set of laboratory exercises using Halobacterium NRC-1 as the model organism for teaching a wide range of subjects, including concepts such as exponential growth, colony formation, mutation, antibiotic resistance, motility, flotation, DNA function, transformation, complementation, biotechnology, genomics, and bioinformatics.

Feedback and input from educators at any level would be greatly appreciated. Please contact Priya DasSarma by email.