The Vta1 transcriptional regulator is required for microsclerotia melanization in Verticillium dahliae

Many fungi are able to produce resting structures, which ensure survival and protect them against various stresses in their habitat such as exposure to UV light, temperature variations, drought as well as changing pH and nutrient conditions. Verticillium dahliae is a plant pathogenic fungus that forms melanized resting structures, called microsclerotia, for survival of time periods without a host. These highly stress resistant microsclerotia persist in the soil for many years and are therefore problematic for an effective treatment of the fungus. The Verticillium transcription activator of adhesion 1 (Vta1) was initially identified as one of several transcriptional regulators that rescue adhesion in non-adhesive Saccharomyces cerevisiae cells. Vta2 and Vta3 are required for early steps in plant infection and colonization and additionally control microsclerotia formation. Here, we show that Vta1 function is different, because it is dispensable for root colonization and infection. Vta1 is produced in the fungal cell during microsclerotia development. Analysis of the deletion mutant revealed that the absence of Vta1 allows microsclerotia production, but they are colorless and no more melanized. Vta1 is required for melanin production and activates transcription of melanin biosynthesis genes including the polyketide synthase encoding PKS1 and the laccase LAC1. The primary function of Vta1 in melanin production is important for survival of microsclerotia as resting structures of V. dahliae.

Verticillium dahliae transcription factors Som1 and Vta3 control microsclerotia formation and sequential steps of plant root penetration and colonisation to induce disease

Verticillium dahliae nuclear transcription factors Som1 and Vta3 can rescue adhesion in a FLO8-deficient Saccharomyces cerevisiae strain. Som1 and Vta3 induce the expression of the yeast FLO1 and FLO11 genes encoding adhesins. Som1 and Vta3 are sequentially required for root penetration and colonisation of the plant host by V. dahliae. The SOM1 and VTA3 genes were deleted and their functions in fungus-induced plant pathogenesis were studied using genetic, cell biology, proteomic and plant pathogenicity experiments. Som1 supports fungal adhesion and root penetration and is required earlier than Vta3 in the colonisation of plant root surfaces and tomato plant infection. Som1 controls septa positioning and the size of vacuoles, and subsequently hyphal development including aerial hyphae formation and normal hyphal branching. Som1 and Vta3 control conidiation, microsclerotia formation, and antagonise in oxidative stress responses. The molecular function of Som1 is conserved between the plant pathogen V. dahliae and the opportunistic human pathogen Aspergillus fumigatus. Som1 controls genes for initial steps of plant root penetration, adhesion, oxidative stress response and VTA3 expression to allow subsequent root colonisation. Both Som1 and Vta3 regulate developmental genetic networks required for conidiation, microsclerotia formation and pathogenicity of V. dahliae.

Persistence of surface domain structures for a bulk ferroelectric above TC

Photoemission electron microscopy performed on a well-prepared surface of BaTiO3 reveals the persistence of surface domains at temperatures well above the bulk Curie temperature. Their patterns follow the ferroelectric domain structure observed at 300 K. The contrast between formerly outward polarized domains and in-plane polarized domains is preserved across the transition, while the contrast of inward polarized domains changes sign. The work functions of different possible structures are compared by first-principles calculations. The domain contrast in photoemission above the bulk Curie temperature is associated with a remaining tetragonal distortion of the topmost unit cells which is stabilized by an ionic surface relaxation.

The Use of a Multi-Double-Crystal Diffractometer to Investigate Nickel Domains

The investigations of the domain structure in Ni single crystals is best performed with a double-crystal diffractometer. Conventional small-angle instruments do not have the necessary angular resolution to distinguish satellites of a main peak due to spin-dependent refraction of unpolarized neutrons by Bloch walls in Ni. With the help of a double-crystal diffractometer operating with lamellae crystals as monochromator and analyzer, the angular resolution is maintained but the intensity enhanced by a factor of 5.4. Within a series of measurements, it was possible to investigate Ni domains due to the high angular resolution of the new multi-double-crystal instrument and this improved intensity. The first results of the domain structure in (110) Ni single crystals and a good estimation of the Bloch wall thickness are given.

[Early management of a fracture of the coxal end of the femur in elderly patients]

The demographical structure of the Federal Republic of Germany leads to an increasing number of very old patients in traumatology. Even minor accidents can cause severe injuries including operative treatment. In this retrospective study the data of 219 patients older than 70 years who had to undergo an operation at the femoral neck region are analyzed. The aim of operative management was a very early operation and a fixation device, that allows an immediate full weight-bearing. Fractures of the femoral neck are stabilized by hemiarthroplasty, fractures of the trochanteric region with the dynamic hip screw. 90% of our patients could be operated within 24 hours, the mortality rate during the first 14 days was 3%.

[Program for calculating diagnostic x-ray spectra]

A code written in BASIC is described which calculates x-ray spectra for tube voltages from 20 to 150 kVDC. Data for the spectral distribution, the mean photon energy, kerma in air, mean energy of the kerma distribution together with 1. and 2. half-value layers for aluminum are obtained. Numerical values for the differential energy intensity function and the Thomson-Whiddington constant were taken from Birch et al. (6). For target angles up to 30 degrees agreement between calculated and experimental data is good. For larger angles some discrepancies appear which could be either due to increased filtration by tungsten (surface roughness) or limited applicability of the data used. The program is tailored to be run on a personal computer.