Randy writes > Peter, have you posted to the List the recent paper about the different strains of nosema? No, but I will tell you why. About two weeks ago I stumbled upon several studies that seemed to contain some startling revelations. Not wanting to overreact, I sent copies off to various people to stimulate discussion, but nothing much came of it. SO, I'm thinking, maybe I'm the only one interested by this stuff. Also, I can't really distribute these papers, as they are copyrighted. I can only post excerpts. What I am seeing is that nosema is a highly variable organism that can infect multiple hosts. Traditional species distinctions were made on the basis of observable physical, behavioral, geographic, or pathological differences. Later species distinctions have been made on the basis of genetic dissimilarities that are often subsequently called into question. Bottom line is: I am not sure that the new nosema is in fact new, or if it has been here all along, or is another variation of nosema spp. Also, I wonder if the PCR tests are distinguishing characters that may or may not have meaning in terms of the behavior or pathology of the various so-called species or varieties. Finally, I don't know if anybody but you and me even cares about this stuff Excerpts from recent research Both species [N. apis and N. ceranae] infect the ventriculus of adult honey bees and are transmitted horizontally via spore ingestion, for example whilst workers clean combs of infected faeces. Of great concern is the apparently higher mortality we observed that N. ceranae imposes on A. mellifera compared to N. apis. Colony level infection experiments in the field are now required to demonstrate a causal link between N. ceranae infection and colony collapse. N. ceranae and N. apis may have both existed in A. mellifera for quite a long period. The morphological records of N. apis show high variability and N. ceranae has been found in Europe and on Martinique Island (unpublished data). The origin of N. ceranae will have to be elucidated by further research. * * * The full length rRNA genes of N. ceranae has also been examined and found identical to those of N. apis. Comparing the rRNA sequences of the isolates from A. mellifera and A. ceranae, it showed no difference in phylogeny, and it may represent no differentiation between the isolates from different hosts. Moreover, the N. ceranae isolates from different areas of the world were obtained through abroad researchers, and these isolates showed little difference in IGS phylogenetic analyses. Recent researches showed that there may be more than two species causing honeybee nosema disease, and it raised the questions about the accuracy of records that attributed the Nosema species infection of A. mellifera. Therefore, a multiplex PCR diagnosis method that could discriminate N. apis and N. ceranae was established in this study. * * * The authors compared the morphological and ultrastructure characters between N. apis and N. ceranae and found that the SSUrRNA sequences differed between the two species. It is not known whether N. ceranae is a new, emerging honeybee parasite or is a naturally occurring species that had been overlooked due to its morphological similarity to N. apis In Spain, the ratio of N. ceranae infection in colonies infected with nosema disease was reported to be as high as 90% (Higes et al., 2006). In the samples from Taiwan and Martinique, only N. ceranae was recovered. An unidentified microsporidium from France shares 96% identity with N. ceranae and 94% identity with N. apis. Moreover, the ITS region was sequenced and aligned with the other ITS sequences (Fig. 3); there were noticeable differences from both N. apis and N. ceranae. The unique rDNA arrangement of N. ceranae was not found in this species. The unidentified species found in France suggested that in addition to N. ceranae and N. apis, other Nosema species might be infecting A. mellifera. The rDNA sequence (including SSUrRNA and ITS) of the unidentified species is an intermediate between those of N. apis and N. ceranae, generating interesting questions about in nosema disease research * * * Characterisation of microsporidian species and differentiation among genetic variants of the same species has typically relied on ribosomal RNA (rRNA) gene sequences. Our data on within-genome rRNA variability call into question the usefulness of rRNA sequences to characterise intraspecific genetic variants in the Microsporidia. -- Peter L Borst Danby, NY USA www.people.cornell.edu/pages/plb6 ******************************************************* * Search the BEE-L archives at: * * http://listserv.albany.edu:8080/cgi-bin/wa?S1=bee-l * *******************************************************