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21.
The FASTPlaqueTB assay is an established diagnostic aid for the rapid detection of Mycobacterium tuberculosis from human sputum samples. Using the FASTPlaqueTB assay reagents, viable Mycobacterium avium subsp. paratuberculosis cells were detected as phage plaques in just 24 h. The bacteriophage used does not infect M. avium subsp. paratuberculosis alone, so to add specificity to this assay, a PCR-based identification method was introduced to amplify M. avium subsp. paratuberculosis-specific sequences from the DNA of the mycobacterial cell detected by the phage. To give further diagnostic information, a multiplex PCR method was developed to allow simultaneous amplification of either M. avium subsp. paratuberculosis or M. tuberculosis complex-specific sequences from plaque samples. Combining the plaque PCR technique with the phage-based detection assay allowed the rapid and specific detection of viable M. avium subsp. paratuberculosis in milk samples in just 48 h.  相似文献   
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Global virulence regulation networks in phytopathogenic bacteria   总被引:3,自引:0,他引:3  
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1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas.  相似文献   
24.
GM1 ganglioside beta-galactosidase (GM1-beta-galactosidase) was purified from normal cat brain and liver by a combination of classical and affinity procedures. The final preparation of brain GM1-beta-galactosidase was enriched over 2000-fold with a 36% yield. However, the product was shown to contain several components by disc gel electrophoresis. GM1-beta-galactosidase was also purified from liver with greater than a 30 000-fold enrichment and 40% yield. The liver enzyme was judged homogeneous by disc gel electrophoresis at pH 4.3, 8.1, and 8.9 and by gel chromatography. Both liver and brain GM1-beta-galactosidase(s) eluted as sharp symmetrical peaks from Sephadex G-200 with molecular weights of 250 000 +/- 50 000. The apparent Km determined for 4-methylumbelliferyl beta-D-galactopyranoside (4-MU-Gal) using partially purified brain GM1-beta-galactosidase was 1.73 X 10(-4) M. Liver GM1-beta-galactosidase gave a Km with 4-MU-Gal of 3.25 X 10(-4) M and for [3H]GM1 ganglioside a Km of 4.51 X 10(-4) M was calculated. The pH optima of brain and liver GM1-beta-galactosidase using 4-MU-Gal was 3.8-4.5. By contrast, liver GM1-beta-galactosidase gave a sharp activity peak at pH 4.2 with [3H]GM1 ganglioside. Inhibition by mercuric chloride and sensitivity to hydrogen peroxide and persulfate suggest the involvement of a sulfhydryl in catalysis.  相似文献   
25.
The gene that is involved in juvenile neuronal ceroid lipofuscinosis (JNCL), or Batten disease--CLN3--has been localized to 16p12, and the mutation shows a strong association with alleles of microsatellite markers D16S298, D16S299, and D16S288. Recently, haplotype analysis of a Batten patient from a consanguineous relationship indicated homozygosity for a D16S298 null allele. PCR analysis with different primers on DNA from the patient and his family suggests the presence of a cytogenetically undetectable deletion, which was confirmed by Southern blot analysis. The microdeletion is embedded in a region containing chromosome 16-specific repeated sequences. However, putative candidates for CLN3, members of the highly homologous sulfotransferase gene family, which are also present in this region in several copies, were not deleted in the patient. If the microdeletion in this patient is responsible for Batten disease, then we conclude that the sulfotransferase genes are probably not involved in JNCL. By use of markers and probes flanking D16S298, the maximum size of the microdeletion was determined to be approximately 29 kb. The microdeletion may affect the CLN3 gene, which is expected to be in close proximity to D16S298.  相似文献   
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