HIGH ENERGY PHYSICS: Bulgarians Sue CERN for Leniency

In cash-strapped Bulgaria, scientists are wondering whether a ticket for a front-row seat in high-energy physics is worth the price: Membership dues in CERN, the European particle physics lab, nearly equal the country's entire budget for competitive research grants. Faced with that grim statistic and a plea for leniency from Bulgaria's government, CERN's governing council is considering slashing the country's membership dues for the next 2 years.     

Aufgaben und Probleme der Serologie in der pflanzlichen Virusforschung

Zusammenfassung Verschiedene Anwendungsmöglichkeiten der Serologie in der pflanzlichen Virusforschung werden diskutiert. Von besonderer Bedeutung sind Antikörper für die Diagnose von Viruskrankheiten und für Verwandtschaftsuntersuchungen. Markierte Antikörper dienen als Nachweisreagentien in histologischen und zytologischen Untersuchungen. Analysen von Oberflächenstrukturen mit Hilfe von Antikörpern wurden bei Pflanzenviren bisher nur selten durchgeführt.

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Summary Several applications of serology in plant virus research are discussed. Antibodies are especially important for diagnostic purposes and for investigations on relationships. Labelled antibodies are used as specific tracers in histological and cytological studies. Up to now, only a few analyses of surface structures have been performed in plant virus work by means of antibodies.

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Résumé Pluseurs modes d'application de la sérologie dans la sphère de la virologie végétale sont discutés. Les anticorps sont d'importance spéciale pour le diagnostic des viroses et pour l'exploration des parentées. On se serve des anticorps marqués comme réactifs histologiques et cytologiques. Jusqu'aujourd'hui des analyses de structures superficielles ont été faites rarement chez les vires végétaux.

     

Seroprevalence of Toxoplasma gondii in mainland and sub-Antarctic New Zealand sea lion (Phocarctos hookeri) populations

AIMS: To investigate the seroprevalence of antibodies to Toxoplasma gondii in New Zealand sea lions (Phocarctos hookeri), as a potential contributor to reproductive failure.

METHODS: Archived sera were sourced from New Zealand sea lions from two recolonising mainland populations in the Otago Peninsula (n=15) and Stewart Island (n=12), as well as a declining population at Enderby Island (n=28) in the New Zealand sub-Antarctic. Sera were tested for antibodies to T. gondii using a commercially available ELISA (with samples considered positive if the sample to positive ratio was?>30%), and latex agglutination test (LAT; with titres ≥1:32 considered positive). Western blot analysis was used to validate the results of a subset of 14 samples.

RESULTS: Five samples from sea lions in mainland locations were confirmed positive for antibodies to T. gondii. Two adult females exhibited high LAT antibody titres (min 1:2048, max 1:4096) on both occasions when sampled 1 and 2 years apart, respectively. No animals from Enderby Island were seropositive.

CONCLUSIONS: Toxoplasma gondii infection is unlikely to be a major contributor to poor reproductive success in New Zealand sea lions. However, continued surveillance is pertinent to assess subclinical and clinical impacts of the parasite on these threatened populations. The commercial tests evaluated here, with further species-specific threshold refinement could provide a fast, inexpensive and reliable indicator of T. gondii exposure in New Zealand sea lions.     

Effect of phosphorus,potassium, and chloride nutrition on cold tolerance of winter canola (Brassica napus L.)

Winter varieties of canola (Brassica napus L.) are susceptible to winterkill. Measurements of photosynthetic efficiency and survival of field-grown canola were used to evaluate the effect of chloride (Cl), potassium (K), and phosphorus (P) nutrition on winter field survival in northwestern USA. In a growth chamber experiment, effects of calcium chloride (CaCl₂), potassium chloride (KCl), ammonium chloride (NH₄Cl), or sodium chloride (NaCl) on the ability to tolerate subfreezing temperatures were evaluated. In the field, overwinter survival was higher, and greater photosynthetic activity continued later into the autumn in plants with increased sap Cl concentrations. In the greenhouse experiment, significantly greater survival occurred in plants with higher sap Cl concentrations, but only in plants that had not been cold acclimated. These results suggested that a greater concentration of chloride ion in the sap of canola plants is related to an increased ability to tolerate subfreezing temperatures, but other processes resulting from cold acclimation may largely obscure this effect.     

Chayote mosaic virus, a New Tymovirus Infecting Cucurbitaceae

ABSTRACT Chayote mosaic virus (ChMV) is a putative tymovirus isolated from chayote crops in Costa Rica. ChMV was characterized at the host range, serological, and molecular levels. ChMV was transmitted mechanically and induced disease symptoms mainly in Cucurbitaceae hosts. Asymptomatic infections were detected in other host families. Serologically, ChMV is related to the Andean potato latent virus (APLV) and the Eggplant mosaic virus (EMV), both members of the genus Tymovirus infecting solanaceous hosts in the Caribbean Basin and South America. The sequence of the genomic RNA of ChMV was determined and its genetic organization was typical of tymoviruses. Comparisons with other tymoviral sequences showed that ChMV was a new member of the genus Tymovirus. The phylogenetic analyses of the coat protein gene were consistent with serological comparisons and positioned ChMV within a cluster of tymoviruses infecting mainly cucurbit or solanaceous hosts, including APLV and EMV. Phylogenetic analyses of the replicase protein gene confirmed the close relationship of ChMV and EMV. Our results suggest that ChMV is related to two tymoviruses (APLV and EMV) of proximal geographical provenance but with different natural host ranges. ChMV is the first cucurbit-infecting tymovirus to be fully characterized at the genomic level.     

Severity and persistence of footrot in Merino sheep experimentally infected with a protease thermostable strain of Dichelobacter nodosus at five sites

Objective To test the hypothesis that ovine footrot associated with a thermostable protease strain of Dichelobacter nodosus undergoes self cure or is sustained as an annually recurring disease, depending on the environment.
Design and procedure Forty Merino sheep from a single blood line were infected with a protease thermostable strain of D nodosus a t each of five sites in Western Australia. Footrot lesions and microscopic evidence of D nodosus were recorded every fortnight for 2.5 years, supplemented by laboratory culture. Rainfall, soil and air temperature, pasture quantity and composition and soil types were also recorded. Flocks that apparently self cured were relocated to a more favourable site for footrot in the final spring season.
Results The maximum prevalence of feet with clinical footrot lesions was 80.6, 1.3, 14.4, 3.8 and 88.1% at the five sites. Severe footrot occurred for three consecutive spring seasons at one site that had clay loam soil and at least 3500 kg/ha total pasture dry matter annually. However, the infection was asymptomatic for up to 10 weeks between outbreaks. D nodosus was isolated from flocks for 2.5 years at only two sites, although there was microscopic evidence of the organism at other sites in the final year. A thermolabile variant (strain U6) of D nodosus was isolated from the two sites where footrot persisted.
Conclusion Depending on time and location, ovine footrot induced by a protease thermostable strain of D nodosus either self cured or persisted as annual outbreaks interspersed with periods of asymptomatic infection.