Publications by authors named "Gunther Neuhaus"

Background: Plant Glycogen Synthase Kinase 3/ SHAGGY-like kinases (GSKs) have been implicated in numerous biological processes ranging from embryonic, flower, stomata development to stress and wound responses. They are key regulators of brassinosteroid signaling and are also involved in the cross-talk between auxin and brassinosteroid pathways. In contrast to the human genome that contains two genes, plant GSKs are encoded by a multigene family.

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Quantitative biology requires high precision measurement of cellular parameters such as surface areas or volumes. Here, we have developed an integrated approach in which the data from 3D confocal microscopy and 2D high-resolution transmission electron microscopy were combined. The volumes and diameters of the cells within one population were automatically measured from the confocal data sets.

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Arabidopsis CBF genes (CBF1-CBF3) encode transcription factors having a major role in cold acclimation, the adaptive process whereby certain plants increase their freezing tolerance in response to low non-freezing temperatures. Under these conditions, the CBF genes are induced and their corresponding proteins stimulate the expression of target genes configuring low-temperature transcriptome and conditioning Arabidopsis freezing tolerance. CBF2 seems to be the most determinant of the CBFs since it also regulates CBF1 and CBF3 expression.

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Arabidopsis (Arabidopsis thaliana) SALT TOLERANCE/B-BOX ZINC FINGER PROTEIN24 (STO/BBX24) is a negative regulator of the light signal transduction that localizes to the nucleus of plant cells and interacts with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) in the yeast (Saccharomyces cerevisiae) two-hybrid system. The protein contains two B-box zinc-finger motives at the N terminus and a conserved motif at the C-terminal part required for the interaction with COP1. BBX24 accumulates during deetiolation of young seedlings in the first hours of exposure to light.

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Currently, sterility testing in the pharmaceutical industry-a mandatory release test for all sterile drug products-takes an incubation time of at least 14 days and is based on liquid media according to the pharmacopoeias. The search is on for a rapid sterility test to reduce this rather long time frame. For this we have chosen the Millipore Milliflex Rapid Microbiology Detection System, which is based on solid nutrient media.

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Unlabelled: The Milliflex Rapid System is used as a rapid microbiological method based on adenosine triphosphate (ATP) bioluminescence in the pharmaceutical industry to quantify the amount of micro-organisms present in water and in bioburden samples. The system can also be used for qualitative analyses, for example, to perform a rapid sterility test. This rapid sterility test has been successfully validated and implemented at Novartis and Sandoz.

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Translocation from the cytosol to the nucleus is an essential step in phytochrome (phy) signal transduction. In the case of phytochrome A (phyA), this step occurs with the help of FHY1 (far-red-elongated hypocotyl 1), a specific transport protein. To investigate the components involved in phyA transport, we used a cell-free system that facilitates the controlled addition of transport factors.

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As research advances acquisition of new data reveals novel aspects on already investigated issues. This is the case for SALT TOLERANCE (STO), an Arabidopsis protein that confers tolerance to high salt concentrations when ectopically expressed in yeast cells. For the last years, STO was considered to participate mainly in the response and tolerance of Arabidopsis to high salinity, as it does in yeast.

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The salt tolerance protein (STO) of Arabidopsis was identified as a protein conferring salt tolerance to yeast cells. In order to uncover its function, we isolated an STO T-DNA insertion line and generated RNAi and overexpressor Arabidopsis plants. Here we present data on the hypocotyl growth of these lines indicating that STO acts as a negative regulator in phytochrome and blue-light signalling.

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To uncover new pathways involved in low-temperature signal transduction, we screened for mutants altered in cold-induced expression of RCI2A, an Arabidopsis gene that is not a member of the CBF/DREB1 regulon and is induced not only by low temperature but also by abscisic acid (ABA), dehydration (DH) and NaCl. This was accomplished by generating a line of Arabidopsis carrying a transgene consisting of the RCI2A promoter fused to the firefly luciferase coding sequence. A number of mutants showing low or high RCI2A expression in response to low temperature were identified.

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Previous investigations suggested that specific auxin spatial distribution due to auxin movements to particular embryonic regions was important for normal embryonic pattern formation. To gain information on the molecular mechanism(s) by which auxin acts to direct pattern formation in specific embryonic regions, the role of a plasma membrane (PM) ATPase was evaluated as downstream target of auxin in the present study. Western-blot analysis revealed that the PM H(+)-ATPase expression level was significantly increased by auxin in wheat (Triticum aestivum) embryos (two-three times increase).

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The hypersensitive response (HR) in plants is a programmed cell death that is commonly associated with disease resistance. A novel mutation in Arabidopsis, hlm1, which causes aberrant regulation of cell death, manifested by a lesion-mimic phenotype and an altered HR, segregated as a single recessive allele. Broad-spectrum defense mechanisms remained functional or were constitutive in the mutant plants, which also exhibited increased resistance to a virulent strain of Pseudomonas syringae pv tomato.

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Rapid auxin effects on H+ pumping across the plasma membrane precede auxin-induced elongation growth of hypocotyls and swelling of guard cells, as well as auxin inhibition of root growth. To investigate whether auxin-signalling mechanisms in such diverse cell types are similar, we characterized these responses in various tissues of the diageotropica (dgt) mutant of tomato (Lycopersicon esculentum Mill.).

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