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Showing papers by "University of Basel published in 1994"


Journal ArticleDOI
01 Dec 1994-Yeast
TL;DR: A dominant resistance module, for selection of S. cerevisiae transformants, which entirely consists of heterologous DNA is constructed and tested, and some kanMX modules are flanked by 470 bp direct repeats, promoting in vivo excision with frequencies of 10–3–10–4.
Abstract: We have constructed and tested a dominant resistance module, for selection of S. cerevisiae transformants, which entirely consists of heterologous DNA. This kanMX module contains the known kanr open reading-frame of the E. coli transposon Tn903 fused to transcriptional and translational control sequences of the TEF gene of the filamentous fungus Ashbya gossypii. This hybrid module permits efficient selection of transformants resistant against geneticin (G418). We also constructed a lacZMT reporter module in which the open reading-frame of the E. coli lacZ gene (lacking the first 9 codons) is fused at its 3' end to the S. cerevisiae ADH1 terminator. KanMX and the lacZMT module, or both modules together, were cloned in the center of a new multiple cloning sequence comprising 18 unique restriction sites flanked by Not I sites. Using the double module for constructions of in-frame substitutions of genes, only one transformation experiment is necessary to test the activity of the promotor and to search for phenotypes due to inactivation of this gene. To allow for repeated use of the G418 selection some kanMX modules are flanked by 470 bp direct repeats, promoting in vivo excision with frequencies of 10(-3)-10(-4). The 1.4 kb kanMX module was also shown to be very useful for PCR based gene disruptions. In an experiment in which a gene disruption was done with DNA molecules carrying PCR-added terminal sequences of only 35 bases homology to each target site, all twelve tested geneticin-resistant colonies carried the correctly integrated kanMX module.

2,727 citations


Journal ArticleDOI
05 Aug 1994-Science
TL;DR: The finding that ey of Drosophila, Small eye of the mouse, and human Aniridia are encoded by homologous genes suggests that eye morphogenesis is under similar genetic control in both vertebrates and insects, in spite of the large differences in eye morphology and mode of development.
Abstract: A Drosophila gene that contains both a paired box and a homeobox and has extensive sequence homology to the mouse Pax-6 (Small eye) gene was isolated and mapped to chromosome IV in a region close to the eyeless locus. Two spontaneous mutations, ey2 and eyR, contain transposable element insertions into the cloned gene and affect gene expression, particularly in the eye primordia. This indicates that the cloned gene encodes ey. The finding that ey of Drosophila, Small eye of the mouse, and human Aniridia are encoded by homologous genes suggests that eye morphogenesis is under similar genetic control in both vertebrates and insects, in spite of the large differences in eye morphology and mode of development.

1,069 citations


Journal ArticleDOI
30 Dec 1994-Cell
TL;DR: It is suggested that coatomer plays an essential role in retrograde Golgi-to-ER transport and retrieval of dilysine-tagged proteins back to the ER.

803 citations



Journal ArticleDOI
TL;DR: The authors have adopted a new nomenclature for the laminins, in which the previous A, B1 and B2 chains, and their isoforms, are alpha, beta and gamma, followed by an arabic numeral to identify the isoform.

743 citations


Journal ArticleDOI
TL;DR: A unifying nomenclature for PRs is proposed based on their grouping into families sharing amino acid sequences, serological relationship, and/or enzymatic or biological activity, and novel proteins identified by electrophoresis or chromatography along with those established by other workers.
Abstract: Pathogenesis-related proteins (abbreviated PRs) are defined as plant proteins that are induced in pathological or related situations. We propose a unifying nomenclature for PRs based on their grouping into families sharing amino acid sequences, serological relationship, and/or enzymatic or biological activity. The nomenclature classifies novel proteins identified by electrophoresis or chromatography along with those established by other workers. The previously proposed system of the five well-established families from tobacco is extended to accommodate a further six families. Families are indicated by arabic numerals and individual members are named by lower case letters in the order in which they are described. Additional rules are proposed to deal with forms containing more than a single polypeptide and as yet unclassified PRs. PR genes whose sequences are conserved but whose designations are not based on function are to be designated Ypr in accordance with the recommendations of the Commission on Plant Gene Nomenclature.

602 citations


Journal ArticleDOI
01 Jun 1994-Test
TL;DR: An overview of the subject of robust Bayesian analysis is provided, one that is accessible to statisticians outside the field, and recent developments in the area are reviewed.
Abstract: Robust Bayesian analysis is the study of the sensitivity of Bayesian answers to uncertain inputs. This paper seeks to provide an overview of the subject, one that is accessible to statisticians outside the field. Recent developments in the area are also reviewed, though with very uneven emphasis.

587 citations


Journal ArticleDOI
TL;DR: In this article, a micromechanical Si lever was used to detect heat fluxes induced by the differential thermal expansion of the lever using the optical position sensor from a force microscope.

487 citations


Journal ArticleDOI
TL;DR: A model for the evolution of cooperation shows that two conditions are necessary for cooperation to be stable: a hunting success rate that is low for single hunters and increases with group size, and a social mechanism limiting access to meat by non-hunters.

472 citations


Book ChapterDOI
01 Jan 1994
TL;DR: In this article, a formal theory of Tannaka duality inspired by Ross Street's "formal theory of monads" is presented. But the formal theory is restricted to the case where the representations of the representations are over an arbitrary commutative ring rather than a field.
Abstract: — A Tannakian category is an abelian tensor category equipped with a fiber functor and additional structures which ensure that it is equivalent to the category of representations of some affine groupoid scheme acting on the spectrum of a field extension. If we are working over an arbitrary commutative ring rather than a field, the categories of representations cease to be abelian. We provide a list of sufficient conditions which ensure that an additive tensor category is equivalent to the category of representations of an affine groupoid scheme acting on an affine scheme, or, more generally, to the category of representations of a Hopf algebroid in a symmetric monoidal category. In order to do this we develop a “formal theory of Tannaka duality” inspired by Ross Street’s “formal theory of monads.” We apply our results to certain categories of filtered modules which are used to study p-adic Galois representations. Résumé (La théorie formelle de dualité tannakienne). — Une catégorie tannakienne est une catégorie abélienne tensorielle munie d’un foncteur fibré et de structures additionnelles de manière à être équivalente à la catégorie des représentations d’un groupoïde affine agissant sur le spectre d’une extension de corps. Si l’on remplace les corps par des anneaux commutatifs, les catégories des représentations ne seront plus abéliennes. Nous donnons des conditions suffisantes pour qu’une catégorie additive tensorielle soit équivalente à la catégorie des représentations d’un schéma en groupoïdes affines, ou plus généralement, à la catégorie des représentations d’un algebroïde de Hopf dans une catégorie symmétrique monoïdale. Pour ce faire nous développons une « théorie formelle de dualité tannakienne » inspirée par la « théorie formelle des monades » de Ross Street. Nous appliquons nos résultats à certaines catégories des modules filtrés qui sont utilisées pour étudier les représentations galoisiennes p-adiques. © Astérisque 357, SMF 2013

463 citations



Journal ArticleDOI
21 Oct 1994-Cell
TL;DR: The results establish MLP as an essential promoter of myogenesis and suggest that LIM-only proteins act via similar mechanisms to regulate aspects of cell differentiation.

Journal ArticleDOI
TL;DR: In this paper, the problem of financial contracting and renegotiation between a firm and outside investors when the firm cannot commit to future payouts, but assets can be contracted upon was studied, and it was shown that a capital structure with multiple investors specializing in short-term and long-term claims is superior to a structure with only one type of claim.
Abstract: We study the problem of financial contracting and renegotiation between a firm and outside investors when the firm cannot commit to future payouts, but assets can be contracted upon. We show that a capital structure with multiple investors specializing in short-term and long-term claims is superior to a structure with only one type of claim, because this hardens the incentives for the entrepreneur to renegotiate the contract ex post. Depending on the parameters, the optimal capital structure also differentiates between state-independent and state-dependent longterm claims, which can be interpreted as long-term debt and equity. © 1994 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.

Journal ArticleDOI
TL;DR: In the representation theory of the group GLn(C), an important tool are the Young tableaux, which are the irreducible representations are in one-to-one correspondence with the shapes of these tableaux as discussed by the authors.
Abstract: In the representation theory of the group GLn(C), an important tool are the Young tableaux. The irreducible representations are in one-to-one correspondence with the shapes of these tableaux. Let T be the subgroup of diagonal matrices in GLn(C). Then there is a canonical way to assign a weight of T to any Young tableau such that the sum over the weights of all tableaux of a fixed shape is the character CharV of the corresponding GLn(C)-module V . Note that this gives not only a way to compute the character, it gives also a possibility to describe the multiplicity of a weight in the representation: It is the number of different tableaux of the same weight. Eventually, the Littlewood-Richardson rule describes the decomposition of tensor products of GLn(C)modules purely in terms of the combinatoric of these Young tableaux.

Journal ArticleDOI
TL;DR: PCR and Western immunoblotting, using primers specific for eubacteria and antibodies recognizing type-specific antigens, indicated that strain BH72 could colonize rice plants systemically, probably mediated by longitudinal spreading through vessels.
Abstract: The invasive properties of Azoarcus sp. strain BH72, an endorhizospheric isolate of Kallar grass, on gnotobiotically grown seedlings of Oryza sativa IR36 and Leptochloa fusca (L.) Kunth were studied. Additionally, Azoarcus spp. were localized in roots of field-grown Kallar grass. To facilitate localization and to assure identity of bacteria, genetically engineered microorganisms expressing beta-glucuronidase were also used as inocula. beta-Glucuronidase staining indicated that the apical region of the root behind the meristem was the most intensively colonized. Light and electron microscopy showed that strain BH72 penetrated the rhizoplane preferentially in the zones of elongation and differentiation and colonized the root interior inter- and intracellularly. In addition to the root cortex, stelar tissue was also colonized; bacteria were found in the xylem. No evidence was obtained that Azoarcus spp. could reside in living plant cells; rather, plant cells were apparently destroyed after bacteria had penetrated the cell wall. A common pathogenicity test on tobacco leaves provided no evidence that representative strains of Azoarcus spp. are phytopathogenic. Compared with the control, inoculation with strain BH72 significantly promoted growth of rice seedlings. This effect was reversed when the plant medium was supplemented with malate (0.2 g/liter). N2 fixation was apparently not involved, because the same response was obtained with a nifK mutant of strain BH72, which has a Nif- phenotype. Also, Western blot (immunoblot) analysis of protein extracts from rice seedlings gave no indication that nitrogenase was present. PCR and Western immunoblotting, using primers specific for eubacteria and antibodies recognizing type-specific antigens, respectively, indicated that strain BH72 could colonize rice plants systemically, probably mediated by longitudinal spreading through vessels.

Journal ArticleDOI
TL;DR: The data indicate that trehalose accumulation may increase the thermotolerance of yeast by enhancing protein stability in intact cells by reducing the heat-induced formation of protein aggregates.
Abstract: In baker's yeast (Saccharomyces cerevisiae), accumulation of the non-reducing disaccharide, trehalose, is triggered by stimuli that activate the heat-shock response. Previously, trehalose levels have been shown to be closely correlated with thermotolerance, suggesting a protective function of this substance. Genetic evidence in support of this view is presented in an accompanying paper [De Virgilio, C., Hottiger, T., Dominguez, J., Boller, T. & Wiemken, A. (1993) Eur. J. Biochem. 219, 179-186]. In this study, we have examined the effect of trehalose on the thermal stability of proteins, a parameter thought to be a major determinant of thermotolerance. Physiological concentrations of trehalose (up to 0.5 M) were found to efficiently protect enzymes of yeast (glucose-6P-dehydrogenase, phosphoglucose-isomerase) as well as enzymes of non-yeast origin (bovine glutamic dehydrogenase, EcoRI) against heat inactivation in vitro. Trehalose also reduced the heat-induced formation of protein aggregates. The disaccharide proved to be a compatible solute, as even at very high concentrations (up to 1 M) it did not significantly interfere with the activity of test enzymes. Trehalose was at least as good or better a protein stabilizer than any of a number of other compatible solutes (including sugars, polyalcohols and amino acids), while the structurally related trehalose-6P was devoid of any protective effect. Thermoprotection of enzymes by trehalose was evident even in solutions containing high concentrations of yeast protein or substrate. The data indicate that trehalose accumulation may increase the thermotolerance of yeast by enhancing protein stability in intact cells.

Journal ArticleDOI
24 Nov 1994-Nature
TL;DR: It is reported that song sparrows that survived a severe population bottleneck were a non-random subset of the pre-crash population with respect to inbreeding, and that natural selection favoured outbred individuals, suggesting that inbreeding depression was expressed in the face of an environmental challenge.
Abstract: The genetic and demographic consequences of population subdivision have received considerable attention from conservation biologists. In particular, losses of genetic variability and reduced viability and fecundity due to inbreeding (inbreeding depression) are of concern. Studies of domestic, laboratory and zoo populations have shown inbreeding depression in a variety of traits related to fitness. Consequently, inbreeding depression is widely accepted as a fact. Recently, however, the relative impact of inbreeding on the viability of natural populations has been questioned. Work on the cheetah (Acinonyx jubatus), for example, has emphasized the overwhelming importance of environmental factors on mortality in the wild. Here we report that song sparrows (Melospiza melodia) that survived a severe population bottleneck were a non-random subset of the pre-crash population with respect to inbreeding, and that natural selection favoured outbred individuals. Thus, inbreeding depression was expressed in the face of an environmental challenge. Such challenges are also likely to be faced by inbred populations of endangered species. We suggest that environmental and genetic effects on survival may interact and, as a consequence, that their effects on individuals and populations should not be considered independently.

Journal ArticleDOI
TL;DR: TOR1 and TOR2 are likely similar but not identical, rapamycin-sensitive PI kinases possibly regulated by phosphorylation, and may be components of a novel signal transduction pathway controlling progression through G1.
Abstract: The Saccharomyces cerevisiae genes TOR1 and TOR2 were originally identified by mutations that confer resistance to the immunosuppressant rapamycin. TOR2 was previously shown to encode an essential 282-kDa phosphatidylinositol kinase (PI kinase) homologue. The TOR1 gene product is also a large (281 kDa) PI kinase homologue, with 67% identity to TOR2. TOR1 is not essential, but a TOR1 TOR2 double disruption uniquely confers a cell cycle (G1) arrest as does exposure to rapamycin; disruption of TOR2 alone is lethal but does not cause a cell cycle arrest. TOR1-TOR2 and TOR2-TOR1 hybrids indicate that carboxy-terminal domains of TOR1 and TOR2 containing a lipid kinase sequence motif are interchangeable and therefore functionally equivalent; the other portions of TOR1 and TOR2 are not interchangeable. The TOR1-1 and TOR2-1 mutations, which confer rapamycin resistance, alter the same potential protein kinase C site in the respective protein's lipid kinase domain. Thus, TOR1 and TOR2 are likely similar but not identical, rapamycin-sensitive PI kinases possibly regulated by phosphorylation. TOR1 and TOR2 may be components of a novel signal transduction pathway controlling progression through G1.

Journal Article
TL;DR: Although the bulk of CD4+ T cell-mediated lysis appears to be Fas induced, the fact that the effector phase of A20.2J lysis is only partially Ca2+ independent indicates that other pathways also contribute to target cell death.
Abstract: Activation of the Fas cell surface molecule, either by specific antibody or by its as yet unidentified ligand, has been shown to induce apoptosis. Because apoptosis is also evoked in target cells by cytolytic T cells, we investigated whether the Fas pathway is involved in CD4+ T cell-mediated cytotoxicity. Analysis of Fas expression in APC, such as the B lymphoma A20.2J and MHC class II-transfected fibroblasts RT2.3, revealed a correlation between the degree of expression and sensitivity to cytotoxic attack, high level of Fas expression in A20.2J being associated with efficient lysis. To examine whether increased Fas expression in RT2.3 would render these cells more susceptible to CD4+ CTL lysis, they were transfected with a Fas gene expression vector. Indeed, Fas- but not mock-transfected RT2.3 proved to be more sensitive to lysis by either Ag specifically or nonspecifically activated CD4+ CTL. Similarly, MHC class II-negative, Fas-transfected L1210 leukemia cells were lysed with nonspecifically activated CD4+ CTL. The importance of the Fas engagement in CD4+ CTL-mediated cytotoxicity is further substantiated by the failure of both cloned and normal CD4+ CTL to lyse B cell blasts from Ipr mice. These mice are known to have a defect in functional Fas expression. Although the bulk of CD4+ T cell-mediated lysis appears to be Fas induced, the fact that the effector phase of A20.2J lysis is only partially Ca2+ independent indicates that other pathways also contribute to target cell death.

Journal ArticleDOI
TL;DR: It is suggested that MEP mimics small natural ligands capable of expanding one subset of gamma delta T cells and that this recognition of nonpeptide antigens may play an important role in human immunity to pathogens.
Abstract: gamma delta T cells respond to a variety of microbial pathogens and transformed cells. Their limited receptor repertoire and activation by mycobacterial antigens resistant to proteases suggest that they may recognize nonpeptide antigens. We have tested a variety of nonpeptide molecules for stimulation of human gamma delta T cells. Synthetic alkyl phosphates, particularly monoethyl phosphate (MEP), selectively activated gamma delta T cells and stimulated their proliferation in vitro. All gamma delta T cells stimulated by MEP expressed V gamma 2/V delta 2 receptors. The purified natural ligand of mycobacteria is chemically similar to, though distinct from, MEP and contains a phosphate residue that is critical for biological activity. Recognition and expansion of a specific T-cell receptor-bearing population to non-peptide ligands is unprecedented among T cells. We suggest that MEP mimics small natural ligands capable of expanding one subset of gamma delta T cells and that this recognition of nonpeptide antigens may play an important role in human immunity to pathogens.

Journal ArticleDOI
TL;DR: In this article, the authors derived the conductance response to oscillating external chemical potentials, and determined the screening potential for slowly oscillating potentials from the condition of local charge neutrality.
Abstract: In the presence of a static potential drop a carrier stream incident at a contact of the sample is partitioned into the other contacts according to the transmission probabilities of the sample. The bare response to oscillating potentials, on the other hand, violates current conservation due to the piling up of unscreened charges in the sample, and has to be modified by taking the induced screening potential into account. We present a novel derivation of the conductance response to oscillating external chemical potentials, find the response to an arbitrary internal potential in terms of functional derivatives with respect to the local potential of the scattering matrix of the conductor, and determine the screening potential for slowly oscillating potentials from the condition of local charge neutrality. We find that the current partitioning depends on ratios of local densities of states which reflect the injection and emission properties of the contacts of the sample.

Journal ArticleDOI
TL;DR: Examination of mutants defective in genes coding for key enzymes involved in trehalose metabolism with respect to the heat-induced and stationary-phase-induced accumulation oftrehalose and the acquisition of thermotolerance provides strong genetic evidence that heat- induced synthesis of tre Halose is an important factor for thermot tolerance induction.
Abstract: In the yeast Saccharomyces cerevisiae, accumulation of the non-reducing disaccharide trehalose is triggered by various stimuli that activate the heat-schock response. Several studies have shown a close correlation between trehalose levels and tolerance to heat stress, suggesting that trehalose may be a protectant which contributes to thermotolerance. In this study, we have examined mutants defective in genes coding for key enzymes involved in trehalose metabolism with respect to the heat-induced and stationary-phase-induced accumulation of trehalose and the acquisition of thermotolerance. Inactivation of either TPS1 or TPS2, encoding subunits of the trehalose-6-phosphate synthase/phosphatase complex, caused an inability to accumulate trehalose upon a mild heat-shock or upon initiation of the stationary phase and significantly reduced the levels of heat-induced and stationary-phase-induced thermotolerance. Deletion of NTH1, the gene coding for the neutral trehalase, resulted in a defect in trehalose mobilization during recovery from a heat shock which was paralleled by an abnormally slow decrease of thermotolerance. Our results provide strong genetic evidence that heat-induced synthesis of trehalose is an important factor for thermotolerance induction. In an accompanying study [Hottiger, T., De Virgilio, C., Hall, M. N., Boller, T. & Wiemken, A. (1993) Eur. J. Biochem. 219, 187-193], we present evidence that the function of heat-induced trehalose accumulation may be to increase the thermal stability of proteins.

Journal ArticleDOI
TL;DR: The physical and evolutionary connections between different types of galaxies that overlap in the same portion of the mass-spectrum of galaxies are discussed in this article, with particular attention to how well currently available data can constrain the formation of dE's.
Abstract: Dwarf elliptical (dE) galaxies, with blue absolute magnitudes typically fainter thanMB=−16, are the most numerous type of galaxy in the nearby universe. Tremendous advances have been made over the past several years in delineating the properties of both Local Group satellite dE's and the large dE populations of nearby clusters. We review some of these advances, with particular attention to how well currently available data can constrain (a) models for the formation of dE's (b) the physical and evolutionary connections between different types of galaxies (nucleated and nonnucleated dE's, compact E's, irregulars, and blue compact dwarfs) that overlap in the same portion of the mass-spectrum of galaxies (c) the contribution of dE's to the galaxy luminosity functions in clusters and the field (d) the star-forming histories of dE's and their possible contribution to faint galaxy counts, and (e) the clustering properties of dE's.

Journal ArticleDOI
29 Jul 1994-Cell
TL;DR: It is proposed that specification of distinct cell fates in response to different concentrations of dpp may be achieved combinatorially by the sax and tkv receptors.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the technique and review recent progress in the field of near-field optical microscopy (SNOM) and present a review of the state-of-the-art.
Abstract: Scanning Near-field Optical Microscopy (SNOM) allows the investigation of optical properties on subwavelength scales. During the past few years, more and more attention has been given to this technique that shows enormous potential for imaging, sensing and modification at near-molecular resolution. This article describes the technique and reviews recent progress in the field.

Journal ArticleDOI
08 Apr 1994-Science
TL;DR: The role of protein degradation in mitochondrial homeostasis was explored by cloning of a gene from Saccharomyces cerevisiae that encodes a protein resembling the adenosine triphosphate (ATP)-dependent bacterial protease Lon, which has a typical mitochondrial matrix-targeting sequence at its amino terminus.
Abstract: The role of protein degradation in mitochondrial homeostasis was explored by cloning of a gene from Saccharomyces cerevisiae that encodes a protein resembling the adenosine triphosphate (ATP)-dependent bacterial protease Lon. The predicted yeast protein has a typical mitochondrial matrix-targeting sequence at its amino terminus. Yeast cells lacking a functional LON gene contained a nonfunctional mitochondrial genome, were respiratory-deficient, and lacked an ATP-dependent proteolytic activity present in the mitochondria of Lon+ cells. Lon- cells were also impaired in their ability to catalyze the energy-dependent degradation of several mitochondrial matrix proteins and they accumulated electron-dense inclusions in their mitochondrial matrix.

Journal ArticleDOI
TL;DR: Evidence is presented that endocytosis is required for this low pH-dependent growth ofeast mutants that are defective in acidification of the lysosome-like vacuole and that these mutants defective in uptake of alpha-factor sort newly synthesized vacuolar proteins correctly, while those which may be defective in subsequent transport steps secrete at least a fraction of the newly synthesised soluble vacuol proteins.
Abstract: Yeast mutants that are defective in acidification of the lysosome-like vacuole are able to grow at pH 5.5, but not at pH 7. Here, we present evidence that endocytosis is required for this low pH-dependent growth and use this observation to develop a screen for mutants defective in endocytosis. By isolating mutants that cannot grow when they lack the 60-kD vacuolar ATPase subunit (encoded by the VAT2 gene), we isolated a number of vat2-synthetic lethal (Vsl-) mutant strains. Seven of the Vsl- mutants are defective in endocytosis. Four of these mutant strains (end8-1, end9-1, end10-1, and end11-1) show altered uptake of the endocytosed ligand, alpha-factor, and three (end12-1, end12-2, and end13-1) are probably defective in transfer of internalized material to the vacuole. Most of the mutations also confer a strong Ts- growth defect. The mutants defective in uptake of alpha-factor sort newly synthesized vacuolar proteins correctly, while those which may be defective in subsequent transport steps secrete at least a fraction of the newly synthesized soluble vacuolar proteins. The mutations that result in a defect in alpha-factor uptake are not allelic to any of the genes previously shown to encode endocytic functions.

Journal ArticleDOI
TL;DR: It is demonstrated that End3p is specifically involved in the internalization step of endocytosis and was shown to be required for proper organization of the actin cytoskeleton and for the correct distribution of chitin at the cell surface.
Abstract: Two Saccharomyces cerevisiae mutants, end3 and end4, defective in the internalization step of endocytosis, have previously been isolated. The END3 gene was cloned by complementation of the temperature-sensitive growth defect caused by the end3 mutation and the END3 nucleotide sequence was determined. The END3 gene product is a 40-kDa protein that has a putative EF-hand Ca(2+)-binding site, a consensus sequence for the binding of phosphotidylinositol 4,5-bisphosphate (PIP2), and a C-terminal domain containing two homologous regions of 17-19 aa. The EF-hand consensus and the putative PIP2-binding sites are seemingly not required for End3 protein function. In contrast, different portions of the End3p N-terminal domain, and at least one of the two repeated regions in its C-terminus, are required for End3p activity. Disruption of the END3 gene yielded cells with the same phenotype as the original end3 mutant. An end3ts allele was obtained and this allowed us to demonstrate that End3p is specifically involved in the internalization step of endocytosis. In addition, End3p was shown to be required for proper organization of the actin cytoskeleton and for the correct distribution of chitin at the cell surface.

Journal ArticleDOI
TL;DR: The observations suggest that the commonly reported TNC accumulation and N depletion in leaves growing under elevated CO2 are not restricted to the artificial conditions of short-term CO2 enrichment experiments but persist over very long periods, and can be expected to occur in other plant communities also if atmospheric CO2 levels continue to rise.
Abstract: We investigated the carbon supply status in species-rich mediterranean plant communities growing in a bowl-shaped 1-ha “CO2 spring” area near Sienna, Italy. A geothermic “lime-kiln” has provided these communities, for as long as historical records are available, with pure CO2 that mixes with ambient air at canopy level to daytime means of 500–1000 ppm CO2. Immediately outside the spring area similar plant communities are growing on similar substrate, and in the same climate, but under ca. 355 ppm CO2. We found no evidence that plants in the CO2 spring area grow faster, flower earlier or become larger. However, we found very large differences in tissue quality among the 40 species studied inside and outside the spring area. Depending on weather conditions, the mean concentration of total non-structural carbohydrates (TNC, sugars and starch) in leaves of herbaceous plants was 38–47% higher in the spring area. Fast growing ruderals growing on garden soil inside and outside the spring area show the same response. Among trees, leaves of the deciduousQuercus pubscens contain twice as much TNC inside as outside the vent area, whereas evergreenQ. ilex leaves show no significant difference. TNC levels in branch wood paralleled leaf values. TNC in shade leaves was also higher. Elevated CO2 had no effect on the sugar fraction, therefore differences in TNC are due to starch accumulation. Leaf nitrogen concentration decreases under elevated CO2. These observations suggest that the commonly reported TNC accumulation and N depletion in leaves growing under elevated CO2 are not restricted to the artificial conditions of short-term CO2 enrichment experiments but persist over very long periods. Such an alteration of tissue composition can be expected to occur in other plant communities also if atmospheric CO2 levels continue to rise. Effects on food webs and nutrient cycling are likely.

Journal ArticleDOI
TL;DR: In this paper, the spectral function P(k, E) of finite nuclei is derived by combining the nuclear-matter correlated part, evaluated in local-density approximation, with the finite-nucleus single-particle part obtained from mean-field calculations or (e, e′p) experiments.