Infection with Bartonella weissii and detection of Nanobacterium antigens in a North Carolina beef herd

Very recently, Bartonella organisms have been isolated from large ruminants (deer, elk, and dairy and beef cattle) located in the United States and in France. In this study, we report the serologic, microbiologic, and molecular findings related to the isolation of a Bartonella species in North Carolina beef cattle and the detection of nanobacterial antigen using a commercially available enzyme-linked immunosorbent assay. Between August 1998 and September 1999, blood was collected from 38 cattle ranging in age from 1 month to 6.5 years. After a 1-month incubation period, a Bartonella sp. was isolated on a 5% rabbit blood agar plate from three of six EDTA blood samples. PCR amplification of the 16S rRNA gene from all three isolates resulted in a DNA sequence that was 100% identical to that of B. weissii 16S rRNA (GenBank no. AF199502). By IFA testing, 36 of 38 cattle had antibodies (> or =1:64) to Bartonella weissii (bovine origin) antigens. Nanobacterial antigen was detected in 22 of 22 serum samples. We conclude that infection with an organism similar or closely related to B. weissii can occur in North Carolina cattle and that although their actual existence is still controversial Nanobacterium antigens were detected with a commercially available test kit. The epidemiology, vector biology, and potential pathogenicity of these organisms in cattle deserve future consideration.

Cyclic CD8+ lymphopenia in dogs experimentally infected with Bartonella vinsonii subsp. berkhoffii

Until recently, it was presumed that Bartonella vinsonii only infected voles, a species of North American rodents. In April of 1993, however, our laboratory isolated a novel subspecies of B. vinsonii (B. vinsonii subsp. berkhoffii) from the blood of a dog diagnosed with vegetative valvular endocarditis. Subsequently, based on a seroepidemiologic survey of dogs from North Carolina and Virginia presenting for a variety of medical problems, we found evidence supporting a potentially important association between B. vinsonii and Ehrlichia canis co-infection in dogs. In the following study, eight dogs were infected with B. vinsonii: four specific pathogen free dogs and four dogs that had previously been infected with E. canis. Flow cytometric analysis of peripheral blood lymphocytes revealed a cyclic elevation of the CD4/CD8 T-cell ratio that correlated with cyclic CD8+ lymphopenia in all dogs infected with B. vinsonii, regardless of prior exposure to E. canis.

A stable and efficient transformation system for Butyrivibrio fibrisolvens OB156

A 9.5-kb shuttle vector capable of replication and selection in both Escherichia coli and Butyrivibrio fibrisolvens was constructed. Plasmid pUC118 provided replication functions and ampicillin resistance selection in E. coli. In B. fibrisolvens, replication was controlled by the native plasmid pRJF1 from strain OB156, and selectability was provided by a 3.5-kb fragment of plasmid pAM beta 1 containing the erythromycin resistance gene. Optimum conditions for transformation were 15 kV/cm, 2 h recovery, and plating in an agar overlay on medium containing 10 micrograms erythromycin/ml. Maximum efficiency was 1.1 x 10(5) transformants per micrograms plasmid DNA (average 3 x 10(4)), and restriction mechanisms reduced efficiency by a factor of 2 x 10(2). Nonselective growth for 200 generations gave no measurable loss of plasmid.

The use of PCR ribotyping for typing strains of Listeria spp

The potential of PCR ribotyping for discriminating between and within various species of Listeria, as well as strains of Listeria monocytogenes was examined. In total, 49 strains of Listeria monocytogenes and 12 isolates of Listeria spp. were analyzed. The genomic DNA isolated from these strains was subjected to PCR amplification in the regions between 16S and 5S rRNA. Amplifications were performed with both low and high concentrations of Taq polymerase. Length polymorphisms in the amplified DNA products enabled distinction between various strains of Listeria spp. and between various serotypes of L. monocytogenes. Six composite profiles for serotype 4b strains, 8 for 1/2a strains and 11 for 1/2b strains, were observed. In addition, several different PCR ribotyping strategies were evaluated. Restriction fragment length polymorphisms of the spacer region between the 16S and 23S rRNA genes of 16 strains of L. monocytogenes were not observed, except for two isolates. PCR ribotyping analysis displayed promise as an alternative to traditional L. monocytogenes molecular typing methods.

Ni-Co doped TiO2 catalyst for efficient photocatalytic degradation of Malachite Green under UV and direct sunlight

In the present study, combustion-synthesized TiO2 nanoparticles were wet impregnated with Ni, Co, and Ni-Co, respectively. The photocatalytic performance of synthesized catalysts was evaluated against Malachite Green dye. The synthesized materials were characterized for crystallite size, surface morphology, elemental composition, and band gap using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and ultra-violet diffused reflectance spectroscopy, respectively. The optimum parameters for maximum degradation were found by examining the effects of catalyst loading, initial dye concentration, and light intensity. A comparative analysis of Ni-doped, Co-doped, and Ni-Co-doped TiO2 photocatalysts was conducted. The results indicate superior photocatalytic activity of Ni-Co doped TiO2 among the catalysts investigated under UV light. The degradation kinetics was studied, and the underlying degradation mechanism was proposed with the help of LC-MS analysis. Furthermore, a comparative study on the degradation under solar radiation using Ni-Co/TiO2 was conducted.