Pre- and post-embedding immunogold labeling and electron microscopy in plant host tissues of three antigenically unrelated MLOs: primula yellows,tomato big bud and bermudagrass white leaf

Methods are described for pre- and post-embedding immunogold labeling of mycoplasmalike organisms (MLOs) in thin sections of infected plants. Antisera against primula yellows (PY), tomato big bud (TBB) and bermudagrass white leaf (BGWL) MLOs, and a monoclonal antibody (mab) against PY were tested with the three serologically unrelated MLOs. Labeling was specific for each MLO and was localized to the outer surface of the MLOs. The antisera performed well in both pre- and post-embedding experiments; the mab reacted well in pre-embedding conditions but gave no labeling with post-embedding. Glutaraldehyde fixation reduced levels of labeling in post-embedding conditions. The results show that these techniques can be used to differentiate MLOs reliably, and extend the usefulness of electron microscopy in this area.     

Can Enhanced Awareness Change Local School Children’s Knowledge of Carnivores in Northern Tanzania?

We used a four-day program with a pre-test–post-test approach on 355 selected school children to investigate the influence of a wildlife education project on the acquisition of knowledge about large carnivores in Loliondo, Tanzania. After the school program was completed, a significantly higher number of school children correctly identified six carnivore species, compared to when the same identification task was administered prior to the initiation of the school program. This increased knowledge is important for the conservation of large carnivores in general and of African wild dogs, in particular, because the post-test results showed that most school children considered wild dogs to be an important part of the ecosystem. In areas experiencing human– carnivore conflict, it is important to include conservation education programs in school curricula as early as possible to enable students to gain knowledge of large carnivores and their role in ecosystems.     

Occurrence of Citrus psorosis virus in Campania, southern Italy

Citrus psorosis virus (CPsV), genus Ophiovirus, is associated with a severe disease of citrus worldwide. Double antibody sandwich (DAS) ELISA using a polyclonal antiserum, and triple antibody sandwich (TAS) ELISAs, employing the IgG monoclonal antibody (mab) 13C5, and the IgM mab 2A3, were used to detect CPsV in orchards of different citrus varieties in Campania, southern Italy. TAS ELISA with 13C5 detected all the infections detected by DAS ELISA. Overall, 14% of trees younger than 15 years were positive, but only 1% of older trees, suggesting that infected propagating material has been increasingly used in recent years, in the absence of certification. Highest infection rates were in younger trees of sweet orange (22.8%) and clementine (18.6%). CPsV could easily be detected at all seasons of the year tested (June–January); these and earlier results indicate that TAS ELISA using 13C5 is a sensitive, broad-spectrum and reliable diagnostic method useful for routine tests and certification programmes. Of 44 field isolates responding strongly to DAS ELISA and 13C5-TAS ELISA, mab 2A3 gave similar results with 29 isolates, but gave low values with the others, thus providing a degree of differentiation among isolates. To confirm that the ELISA tests were indeed detecting CPsV, samples of 42 ELISA-positive plants were analysed by ISEM in a blind test, and in 38 of these, characteristic virus particles were clearly seen. Although CPsV was frequently and consistently detected in the area sampled, bark scaling symptoms were not seen: possible reasons for this are discussed.