Candida albicans is an opportunistic fungal pathogen responsible for a variety of cutaneous and systemic human infections. Virulence of C. albicans increases upon exposure to some environmental stresses; therefore, we explored phenotypic responses of C. albicans following exposure to the environmental stress of low-shear modeled microgravity. Upon long-term (12-day) exposure to low-shear modeled microgravity, C. albicans transitioned from yeast to filamentous forms at a higher rate than observed under control conditions. Consistently, genes associated with cellular morphology were differentially expressed in a time-dependent manner. Biofilm communities, credited with enhanced resistance to environmental stress, formed in the modeled microgravity bioreactor and had a more complex structure than those formed in control conditions. In addition, cells exposed to low-shear modeled microgravity displayed phenotypic switching, observed as a near complete transition from smooth to "hyper" irregular wrinkle colony morphology. Consistent with the presence of biofilm communities and increased rates of phenotypic switching, cells exposed to modeled microgravity were significantly more resistant to the antifungal agent Amphotericin B. Together, these data indicate that C. albicans adapts to the environmental stress of low-shear modeled microgravity by demonstrating virulence-associated phenotypes.

This survey has identified factors that would assist the establishment and spread of vesicular and other exotic diseases in pigs. The factors included feeding meat scraps (swill), poor farmer knowledge of exotic diseases, ineffective pig owner identification at saleyards, the practice of cash sales that precluded the collection of purchaser details, and inadequate identification of pigs. Tracing the movements of pigs under these circumstances would be difficult.

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The axial Fe3+ center Fe1 with the crystal field parameter b20≈3130×10−4cm−1 is well studied in congruent lithium tantalate crystals. The second axial Fe3+ center Fe2 was discovered and investigated by the electron paramagnetic resonance in stoichiometric samples prepared by vapor transport equilibrium treatment. The crystal field parameter of the Fe2 center (b20≈2050×10−4cm−1) is significantly smaller than for Fe1. The electron nuclear double resonance measurements have shown that hyperfine interactions of the Fe3+ electrons with the surrounding Li nuclei for Fe2 are stronger than for Fe1. Therefore, the conclusion was made that in the case of Fe2 center the iron ion substitutes for Ta and has Li nuclei in the nearest neighborhood, whereas in the case of Fe1 center it substitutes for Li, has Ta nuclei as nearest neighbors and Li nuclei in the second shell only.

Measurements of the angular dependencies of Electron Nuclear Double Resonance (ENDOR) were used for the analysis of the substitution site and local environment of the dominant axial Fe3+ center in LiNbO3 crystals. All components of hyperfine and quadrupole tensors for several shells of Li and Nb nuclei were determined. Since the found isotropic part of the hyperfine interaction of the iron electrons with the Li nuclei was small, it was justified to approximate the anisotropic part by the dipole-dipole interaction of electron and nuclear spins. From the comparison of the calculated and observed ENDOR spectra of the Li nuclei, it was derived that the Fe3+ ion occupies a Li site but is shifted from the regular Li position by 0.009 nm toward the octahedral structural vacancy. There is no evidence for the presence of any charge compensators in the nearest Li and Nb shells, which indicates a distant mechanism of excess charge compensation. ENDOR of Nb nuclei shows that there is a large isotropic hyperfine interaction due to the significant indirect transferred interaction of Fe3+ with nearest off axis Nb nuclei via O2− and polarization of Nb inner electron shells.