The optimal conditions for the production of the killer toxin of Debaryomyces hansenii CYC 1021 have been studied. The lethal activity of the killer toxin increased with the presence of NaCl in the medium used for testing the killing action. Production of the killer toxin was stimulated in the presence of proteins of complex culture media. Addition of nonionic detergents and other additives, such as dimethylsulfoxide enhanced killer toxin production significantly. Killer toxin secretion pattern followed the growth curve and reached its maximum activity at the early stationary phase. Optimal stability was observed at pH 4.5 and temperatures up to 20 degrees C. Above pH 4.5 a steep decrease of the stability was noted. The activity was hardly detectable at pH 5.1.

Aims: The aims of this study were to characterize the cell wall binding site of Debaryomyces hansenii killer toxin to provide a simple purification method and to determine some characteristics of this toxin. Conclusions: The investigation revealed that the killer toxin was mainly adsorbed by (1fi6)-b-D-glucans. This is a low molecular weight protein, probably encoded by chromosomal genes. Significance and Impact of the Study: The specificity of the killer toxin for its receptor provides an effective means to purify the killer toxin. This study is the first to identify the cell wall binding site of this killer toxin, a toxin with properties of industrial relevance.

The atmospheric response to global sea surface temperatures is the leading cause of rainfall variability in the West African Sahel. On interannual periodicities, El Niño–Southern Oscillation, the Atlantic equatorial mode, and Mediterranean warm/cold events primarily drive variations of summer rainfall over the Sahel. Nevertheless, the rainfall response to these modes of interannual SST variability has been suggested to be unstable throughout the observational record. This study explores changes in the leading patterns of covariability between Sahel rainfall and SSTs, analyzing the dynamical mechanisms at work to explain the nonstationary relationship between anomalies in these two fields. A new network of rain gauge stations across West Africa is used for the first time to investigate these instabilities during the period 1921–2010. A hypothesis is raised that the underlying SST background seems to favor some interannual teleconnections and inhibit others in terms of the cross-equatorial SST gradients and associated impacts on the location of the intertropical convergence zone. Results of this study are relevant for improving the seasonal predictability of summer rainfall in the Sahel.

A principal component analysis of the Northern Hemisphere extratropical zonal-mean tropopause variability at intraseasonal time scales is presented in this work. Wavy deformations of the tropopause dominate this variability and explain significantly more variance than changes in the extratropical-mean tropopause height. The first mode is well correlated with the zonal index. Analysis of the dynamical evolution of the modes shows that tropopause deformations are caused by anomalous wave breaking at the tropopause level occurring in a preexisting anomalous stratospheric polar vortex. Specifically, an intense (weak) polar vortex is associated with a rising (sinking) of the polar tropopause, while anomalous wave breaking in the midlatitudes produces a dipolar tropopause change that is consistent with the anomalous meridional eddy flux of quasigeostrophic potential vorticity. These two forcings operate on different time scales and can be separated when the data are filtered at high or low frequency. Baroclinic equilibration seems to play a small role in the extratropical internal tropopause variability and the impact of tropospheric and stratospheric dynamics is quantitatively similar. A similar analysis for the Southern Hemisphere extratropics displays the same qualitative behavior.

Hypersensitivity pneumonitis (HP) or extrinsic allergic alveolitis is a lung disease caused by a large group of inhaled antigens of various sources. The most common HP occurring in the farm environment is classically caused by exposure to various thermophilic actinomycetes and fungi that can grow in the farm environment. Pullularia species and thermophilic actinomycetes have been involved in HP related to humidifier water and saunas. Our case illustrates the value of a site visit in the diagnosis of HP. During a visit to the covered and heated swimming-pool where our patient used to swimm we could see that favourable conditions to fungal growth existed. To determine the possible aetiological agents of a suspected HP, cultures from several parts of the swimming-pool were taken. These cultures showed an intense growth of thermophilic actinomycetes, Neurospora and Aspergillus species. Precipitating antibodies against Neurospora species and Mycropolyspora faeni were detected. A case of HP related to a covered and heated swimming-pool environment is reported. Thermophilic actinomycetes and Neurospora species may be the causing agents.