Dear Hank:
With regards to new antibiotics, there's a lot of researchers working on
that field. I believe there are 6 catagories to consider for anti-microbials:
- new antibiotics - I don't believe that antibiotics are produced to eliminate
the competition in the microbial world, I think they are compounds for
shutting down pathways when a microbe changes its physiology (e.g. vegetative
to spore state, larvae to butterfly, etc.). If that is so, we have only
scratched the surface in available antibiotics
- using old antibiotics in new ways - some antibiotics have side reactions
that are more exciting than their original use (e.g. penicillin that works on
chlamydia with insignificant peptidoglycan, quinolones as anti-virals)
- different delivery mechanisms for antibiotics - bugs act either in the blood
or act as parasites and sequester into cells. Liposomes and new formulations
of liposomes with focused targetting properties are an exciting new field
- stress and growth parameters - some common antibiotic producers may produce
other antibiotics under different growth conditions. Throw in a vitamin pill
that has been dissolved and filter-sterilized and different products form with
Azotobacter.
- buried metabolites - cloning is beginning to open up the doors for new
microbial products. If you run a gel on a cell lysate, you may see about 50
prominant bands, and yet the bug can produce at least 5000 proteins that
interact and produce minor normally undetectable products. Cloning now
amplifies products normally missed
- miscellaneous - hormones may play a role on infection, not because of the
host's immunity but because of their action on the bugs (e.g. insulin inhibits
Pseudomonas pseudomallei)
Take care...John
