Ability of the c-mos product to associate with and phosphorylate tubulin.

The mos proto-oncogene product, pp39mos, is a protein kinase and has been equated with cytostatic factor (CSF), an activity in unfertilized eggs that is thought to be responsible for the arrest of meiosis at metaphase II. The biochemical properties and potential substrates of pp39mos were examined in unfertilized eggs and in transformed cells in order to study how the protein functions both as CSF and in transformation. The pp39mos protein associated with polymers under conditions that favor tubulin oligomerization and was present in an approximately 500-kilodalton "core" complex under conditions that favor depolymerization. beta-Tubulin was preferentially coprecipitated in pp39mos immunoprecipitates and was the major phosphorylated product in a pp39mos-dependent immune complex kinase assay. Immunofluorescence analysis of NIH 3T3 cells transformed with Xenopus c-mos showed that pp39mos colocalizes with tubulin in the spindle during metaphase and in the midbody and asters during telophase. Disruption of microtubules with nocodazole affected tubulin and pp39mos organization in the same way. It therefore appears that pp39mos is a tubulin-associated protein kinase and may thus participate in the modification of microtubules and contribute to the formation of the spindle. This activity expressed during interphase in somatic cells may be responsible for the transforming activity of pp39mos.     

The ras oncoprotein and M-phase activity.

The endogenous mos proto-oncogene product (Mos) is required for meiotic maturation. In Xenopus oocytes, the ras oncogene product (Ras) can induce meiotic maturation and high levels of M-phase--promoting factor (MPF) independent of endogenous Mos, indicating that a parallel pathway to metaphase exists. In addition, Ras, like Mos and cytostatic factor, can arrest Xenopus embryonic cell cleavage in mitosis and maintain high levels of MPF. Thus, in the Xenopus oocyte and embryo systems Ras functions in the M phase of the cell cycle. The embryonic cleavage arrest assay is a rapid and sensitive test for Ras function.     

Prevalence of Toxoplasma gondii in common moles (Talpa europaea)

Background

The prevalence of Toxoplasma gondii in common moles, Talpa europaea, was investigated in order to determine whether moles can serve as an indicator species for T. gondii infections in livestock.

Findings

In total, 86 moles were caught from 25 different sites in the Netherlands. Five different trapping habitats were distinguished: pasture, garden, forest, roadside, and recreation area. No positive samples (brain cysts) were found during microscopic detection (n = 70). Using the Latex Agglutination Test (LAT), sera of 70 moles were examined, whereby no sample reacted with T. gondii antigen. Real Time-PCR tests on brain tissue showed 2 positive samples (2.3%).

Conclusions

Because of the low number of positives in our study, the use of the common mole as an indicator species for livestock infections is currently not recommended.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-014-0048-0) contains supplementary material, which is available to authorized users.     

Variation in organic‐carbon concentration and bulk density in Flemish grassland soils

The different management regimes on grassland soils were examined to determine the possibilities for improved and/or changed land management of grasslands in Flanders (Belgium), with respect to article 3.4 of the Kyoto Protocol. Grassland soils were sampled for soil organic carbon (SOC) and for bulk density. For all grasslands under agricultural use, grazing and mowing + grazing led to higher SOC stocks compared with mowing, and grazing had higher SOC stocks compared with mowing + grazing. Overall, 15.1 ± 4.9 kg OC m^–2 for the clayey texture, 9.8 ± 3.0 kg OC m^–2 for the silty texture, and 11.8 ± 3.8 kg OC m^–2 for the sandy texture were found for grassland under agricultural use to a depth of 60 cm. For seminatural grasslands, different results were found. For both the clayey and silty texture, mowing and mowing + grazing led to higher SOC stocks compared with grazing. The clayey texture had a mean stock of 15.1 ± 6.6, the silty texture of 10.9 ± 3.0, and the sandy texture of 12.1 ± 3.9 kg OC m^–2 (0–60 cm). Lower bulk densities were found under grazed agricultural grassland compared with mown grassland but for seminatural grassland, no clear trends for the bulk density were found. The best management option for maintaining or enhancing SOC stocks in agricultural grassland soils may be permanent grazed grassland. For seminatural grassland, no clear conclusions could be made. The water status of the sampled mown fields was influencing the results for the clayey texture. Overall, the mean SOC stock was decreasing in the order clay > sand > silt. The higher mean SOC concentrations found for the sandy texture, compared to the finer silty texture, may be explained by the historical land use of these soils.     

A spontaneous chlorate-resistant mutant of Azospirillum brasilense Sp245 displays defects in nitrate reduction and plant root colonization

Azospirillum, a soil bacterium capable of colonizing plant roots, can reduce NO₃^-. In this work, a spontaneous chlorate-resistant mutant of Azospirillum brasilense Sp245, named Sp245chl1, was phenotypically characterized. The mutant is defective in both assimilatory and periplasmic dissimilatory nitrate reductase activity. Using the gusA reporter gene methodology, Sp245chl1 was found to be significantly affected in its ability to colonize roots of wheat and rice seedlings.     

Swedish experiments on subsoil compaction by vehicles with high axle load

Abstract. Soil and crop responses to traffic with vehicles having an axle load of 10 tonnes were studied in 9 field experiments. The clay content of the soils ranged from 6 to 85%. The traffic resulted in increased soil bulk density and strength to a depth of 50 cm. Compaction effects persisted below plough depth 7–8 years after traffic. Crop response was negative and increased with clay content of the soil and with traffic intensity and decreased with time. The results indicate that maximum axle loads on arable fields should be less than 10 tonnes, especially on clay soils.     

Epidemiological and immunological aspects of human crisis form factor in falciparum malaria: cell-mediated responses?

Crisis forms in malaria are degenerated intra-erythrocytic asexual parasites which appear at the time of immunologic crisis and thus may be part of the immune response to this disease. The factor(s) involved in this phenomenon are poorly understood, but are believed to be related to products of phagocyte activation. This hypothesis is supported by observations that animals, whose cell-mediated immune responses have been hyperstimulated by BCG, are protected from otherwise lethal malaria infections and their sera induce crisis forms in vitro. Many human serum samples collected from malaria-endemic areas of Sudan induce crisis forms in cultures of Plasmodium falciparum. Two popular models to explain this intra-erythrocytic, anti-parasitic action have been proposed: (i) the presence in the immune serum of a cytotoxic cytokine, crisis form factor, or (ii) that crisis forms result from oxidant stress generated during respiratory bursts associated with phagocyte activation, or indirectly by toxic products of lipid peroxidation produced by reactive oxygen species which appear in the serum during phagocyte respiratory bursts. Experimental evidence has been generated to support both of these hypotheses and both mechanisms may be involved in the induction of crisis forms.     

An Intensive Approach to Atlantic Halibut Fry Production

The larval stage is regarded to be the main bottleneck of halibut production. Halibut eggs were obtained from captive broodstock both by stripping and by natural spawning. Artificial photoperiods were used to increase the total spawning season. Yolk sac larvae are presently produced either in small stagnant units or in large flow through systems. A major consideration is to avoid stress of the larvae, caused by mechanical disturbances of the larvae and by high bacterial load or high ammonia levels in the water.
The experiments showed that halibut larvae began to ingest algae earlier than rotifers Brachionus sp. Supplementation of algae to first feeding tanks resulted in enhanced survival and growth rate of the larvae. Both rotifers and Artemia can be enriched with very high levels of highly unsaturated n-3 fatty acids (n-3 HUFA). Enriched live feed, containing high levels of n-3 HUFA and total lipids, enhanced both survival and growth of the halibut larvae. The highest growth rates were obtained with wild zooplankton and addition of algae, but enriched cultivated feed combined with algae resulted in growth of the same magnitude as with wild zooplankton.