Bacteria turn on fish genes, according to a report in ScienceNOW 17 Mar 2004. All animals have bacteria living in their digestive systems that aid digestion and help keep disease-causing germs under control. To investigate how these germs help their hosts, microbiologists at the University School of Medicine, St Louis, Missouri, have studied Zebra fish that have been hatched and raised in a bacteria-free environment and compared their digestive functions and immune systems with fish living in a normal environment. Bacteria-free fish had defects in their immune systems, were unable to digest their food properly and were not good at keeping the lining of their digestive system in good repair. These results match similar results found in germ-free mice, which also had defects in their immune and digestive processes. Further research revealed over 200 genes behaved differently in germ-free fish compared with normal fish. Sixty six of these genes are analogous to genes whose function is altered in germ-free mice. Scientists then added normal gut bacteria to the fish, species by species, and found that certain gene activity was specific to particular bacteria. They concluded there must be highly specific chemical signalling occurring between bacteria and fish genes, and now plan to use germ-free fish to understand “the influence of beneficial bacteria on animal development”.

Editorial Comment: These studies confirm animals are designed to live with bacteria. In the original good world that God created, all bacteria would be kept under control by planned signalling and so did not cause disease. Even in this fallen world, only a small proportion of bacteria have escaped control. We are only beginning to understand the type of subtle chemical signals involved in interaction between animals and micro-organisms. The more we study it, the more we find evidence of purposeful design. (Ref. bacteria, fish, genes)