Sixty-one Burkholderia cepacia isolates from patients with cystic fibrosis (CF) and four plant isolates were screened for production of the siderophores salicylic acid (SA), pyochelin, cepabactin, and ornibactins and fingerprinted by a PCR-based randomly amplified polymorphic DNA (RAPD) method. Of the 24 RAPD types determined, 22 (92%) were associated with isolates that produced SA, 21 (87%) were associated with isolates that produced ornibactins, 15 (60%) were associated with isolates that produced pyochelin, and 3 (12%) were associated with isolates that produced cepabactin. Of the 24 RAPD types plus 2 phenotypic variants of types 1 and 9, 3 were associated with isolates that produced all four siderophores, 8 were associated with isolates that produced three siderophores, 12 were associated with isolates that produced two siderophores, and 3 were associated with isolates that produced only one siderophore. These results suggest that the numbers and types of siderophores produced by CF isolates of B. cepacia correlate with RAPD type and that SA and ornibactins are the most prevalent siderophores produced.

A competitive enzyme-linked immunosorbent assay (C-ELISA) employing a baculovirus-expressed recombinant nucleoprotein and a monoclonal antibody was developed for the detection of antibodies to type A influenza virus nucleoprotein. The performance of the C-ELISA was evaluated by testing 756 chickens, 1123 turkeys, 707 emus, and 1261 ostriches, for a total of 3847 serum samples. Relative to the agar gel immunodiffusion (AGID) test, the C-ELISA had a sensitivity of 100% for all four species. The C-ELISA's sensitivity relative to the hemagglutination-inhibition (HI) test results was 100% for chicken, turkey, and emu and 96.2% for the ostrich serum samples. More than 90% of the AGID-negative/C-ELISA-positive serum samples were found positive by HI for at least one influenza serotype. The specificity of C-ELISA relative to AGID ranged from 85.5% to 99.8% for sera collected from these species. These results indicated that the C-ELISA was more sensitive and more specific than the AGID test and as sensitive and as specific as the HI test. The C-ELISA has the potential to replace the AGID test for screening sera from avian species, including ratites, for detection of antibodies to type A influenza virus.

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Background: Kar3Vik1 is a heterodimeric kinesin with one catalytic subunit (Kar3) and one noncatalytic subunit (Vik1). Results: Vik1 experiences conformational changes in regions analogous to the force-producing elements in catalytic kinesins. Conclusion: A molecular mechanism by which Kar3 could trigger Vik1's release from microtubules was revealed. Significance: These findings will serve as the prototype for understanding the motile mechanism of kinesin-14 motors in general.It is widely accepted that movement of kinesin motor proteins is accomplished by coupling ATP binding, hydrolysis, and product release to conformational changes in the microtubule-binding and force-generating elements of their motor domain. Therefore, understanding how the Saccharomyces cerevisiae proteins Cik1 and Vik1 are able to function as direct participants in movement of Kar3Cik1 and Kar3Vik1 kinesin complexes presents an interesting challenge given that their motor homology domain (MHD) cannot bind ATP. Our crystal structures of the Vik1 ortholog from Candida glabrata may provide insight into this mechanism by showing that its neck and neck mimic-like element can adopt several different conformations reminiscent of those observed in catalytic kinesins. We found that when the neck is ␣-helical and interacting with the MHD core, the C terminus of CgVik1 docks onto the central ␤-sheet similarly to the ATP-bound form of Ncd. Alternatively, when neck-core interactions are broken, the C terminus is disordered. Mutations designed to impair neck rotation, or some of the neck-MHD interactions, decreased microtubule gliding velocity and steady state ATPase rate of CgKar3Vik1 complexes significantly. These results strongly suggest that neck rotation and neck mimic docking in Vik1 and Cik1 may be a structural mechanism for communication with Kar3.Eukaryotic cells rely on nanometer-sized motors called kinesins to transport cellular components along microtubules (1) or to help build the mitotic spindle and distribute chromosomes between daughter cells (2,3). Recent studies have shown that dynamic interactions between the neck and a short region of either the N or C terminus of the motor domain form a structure responsible for force generation by the neck (4 -7) and that its conformation and interactions with the motor domain core, or regulatory proteins, is linked to the nucleotide-and microtubule-binding state of the motor (8, 9). In kinesin-1, this region forms an N-terminal extension of the motor domain, called the "cover strand" (5), and in kinesin-14 motors this region is at the C terminus, after the ␣6 helix, and has been dubbed the "neck mimic" (8).Kar3 is a kinesin-14 that plays essential roles in mitosis, meiosis, and karyogamy in Saccharomyces cerevisiae and Candida albicans (10 -13). These include cross-linking, stabilizing, and sliding spindle pole microtubules, as well as depolymerizing microtubules (10,14). To accomplish this array of functions, Kar3 associates with two discrete regulatory subunits, Cik1 and Vik1 (14 -16), whose mot...