I have difficulty in accepting Steve Topletz' generalization that
antibiotics are phytotoxic. The mechanism of action of most antibiotics is directed
against metabolic processes, chiefly involving DNA processing, that differ
between bacteria and eukaryotes. Appearances aside, animals and plants are both
eukaryotes and process DNA in a similar fashion. Further consultation with
one technician at Phytotech Labs, who presumably conducted a study employing
God knows what, could hardly justify Topletz' sweeping generalization. Bert Pressman [still trying to instill the principles of the Scientific
Method into orchid culture].
I have to agree with Steve Topletz that most antibiotics are phytotoxic. They attach specific metabolic pathways and the pathways in most bacteria are very similar to the pathways in plants. In terms of metabolic pathways plants and bacteria are closer together than plants and animals. Many of the antibiotics can kill plants the same way they kill bacteria. There are some antibiotics that do not cause problems in plants, these are the ones that have been used in genetic transformation studies. The antibiotic at the concentrations used reduces the grow of the bacteria more than it reduces the growth of the plant cells. It is possible to isolate plant tissue free of the bacteria after several weeks of growth on media containing antibiotics and several transfers to new media. This requires special antibiotics, and a lot of work.
You can not generalize and say all antibiotics are phytotoxic, but most are and do kill plant tissue just as easily as the bacteria. You can not generalize and say that plants and animals are eukaryotes, so they should react the same to antibiotics. The genetics of plants and animals are basically the same, but they are also very different in various ways. The biochemistry of plants and animals are very similar at a gross level, but they are very different in the details.
Plant and animal cell culture are very different on lots of levels, I know I worked with both when I worked in research. You very rarely find antibiotics in plant cell culture media, toxicity and other problems make it an irritant rather than a benefit. On the other had antibiotics are almost always an ingredient in some animal cell culture media to eliminate any chance of bacteria infection. The antibiotic has many benefits in the animal cell culture, that we do not see in plant cell culture.
-- --Tom /---------------------------------------------------------------------------------------- | Tom Hillson Computer Services Manager |(515) 294-1543 College of Agriculture | Iowa State University ----------------------------------------------------------------------------------------- |"The only thing I have too much of is too little time"
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