The viroid theory in relation to plasmagenes, viruses, cancer and plastids
| Autor: | Edgar Altenburg |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Genetics
Host (biology) Viroid food and beverages biochemical phenomena metabolism and nutrition Biology biology.organism_classification Viroids Fat bodies Multicellular organism Symbiosis Neoplasms Viruses Plastids Plastid Metabolic Process Ecology Evolution Behavior and Systematics Function (biology) |
| Zdroj: | The American naturalist. 80 |
| ISSN: | 0003-0147 |
| Popis: | IT has long been known that cockroaches harbor intracellular "bacteroids" in their fat bodies. These are not parasites. They are necessary for the continued existence of their hosts, for if the bacteroids are killed by means of penicillin, their hosts die, as shown recently by C. T. Brues anfd Ruth C. Dunn (1945). The penicillin itself is non-toxic to the host tissues proper. The bacteroids are therefore symbionts. They undoubtedly are necessary for some cell process, perhaps for the building' up of some vitamin, for its utilization, or for some other metabolic process. Bacteroids are found in the fat bodies of all the Blattidae and in the termites. They also occur in'the intestinal cells of ants. In fact, intra-cellular bacteroids are probably not at all unusual in multicellular organisms, and it seems likely that they are symbionts in all instances in which they are normal constituents of the cell. Symbiosis is of course very common in both the plant and animal kingdoms, but we are at present concerned only with intra-cellular symbionts which are not green and which have some useful function other than the obvious one that depends on the presence of chlorophyll. Now, it is conceivable that there exist ultra-microscopic organisms which are akin to viruses but which are useful symbionts, and that these symbionts occur universally within the cells of larger organisms. We might call these supposed symbionts viroids. They would be analogous to the bacteroids above mentioned in that they would be of value to their host in connection with one or more cell processes. Ordinarily the biologist would be unaware of their existence. But if they should mutate, they might |
| Databáze: | OpenAIRE |
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