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Nanobacteria:
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Nanobacteria:
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Biology is the study of living things. Whether a single cell or a Sequoia tree, a humpback whale or a human being, you have an intuitive sense of what it means to be a biological organism. Sometimes, however, the designation of something as a living thing is not so obvious. A recent example of this is the discovery of nanobacteria.
Bacteria are prokaryotic cells. Prokaryotes lack the internal, membrane-bound structures associated with eukaryotic cells (your body is made up of eukaryotic cells). Bacteria are extremely abundant and versatile, occurring in every environment on Earth (including inside and outside your body). Many bacteria can cause diseases. The name, nanobacteria, refers to the very small size of these organisms (on the order of 0.2µm to 0.5µm). This class of bacteria was originally isolated from human and cow blood. It has been proposed that these bacteria function to stimulate a process called biomineralization.
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Biomineralization is a good thing when it occurs in the correct location, but often this process occurs in the wrong place at the wrong time. The formation of kidney stones is a good example of this kind of pathological (disease-related) form of biomineralization. Nanobacteria have been isolated from within human kidney stones, leading to the suggestion that these bacteria may be the cause of this disease.
Over the next several class meetings we will be considering the evidence for the existence of nanobacteria and their role in the process of biomineralization.
| Assignment for Part I: The fundamental issue under consideration is whether nanobacteria are alive. How would you decide this question? To answer this you need to think about the properties common to all living things and how you would test whether the nanobacteria possessed these properties. |
| Homework: What are the properties of a biological organism? Think of at least THREE properties of life. Fill out the table on the Work Sheet for Part I and bring it with you to the next class period. Choose ONE property of life and propose a way you could test for that property. |
Image Credit: Detail from SEM of biofilm material. Cisar et al., 2000 (PNAS 97:11511-11515).
Date Posted: 12/05/01 nas
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