Rust (fungus) of the rust fungi "Cronartium ribicola", preventing the formation of basidiospores which infect the primary host. Although spores from white pines cannot infect other white pines, survival spores may overwinter on infected pines and reinfect "Ribes" spp. the following season. Infected tissue is removed from white pines and strict quarantines of "Ribes" spp. are maintained in high risk areas. "Puccinia graminis" is a macrocyclic heteroecious fungus that causes wheat stem rust disease. The repeating stage in this fungus occurs on wheat and not the alternate host, barberry. The repeating stage allows the disease to persist in wheat even though the
Anaerobic organism using hydrogenosomes. Some organisms metabolise primarily using glycogen, for example the Nereid (worm)s and some polychaetes, or the juvenile form of the pork parasite "Trichinella spiralis" which causes trichinosis. Anaerobic organism An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present. (In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment.) An anaerobic organism may be unicellular (e.g. protozoans, bacteria) or multicellular. For practical purposes, there are three categories of anaerobe: obligate anaerobes, which are harmed by the presence