11 results on '"J. Wendland"'
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2. Draft Genome Sequence of Saccharomycopsis fodiens CBS 8332, a Necrotrophic Mycoparasite with Biocontrol Potential.
- Author
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Junker K, Hesselbart A, and Wendland J
- Abstract
Saccharomycopsis fodiens is an ascomycetous necrotrophic mycoparasite. Predator-prey interaction leads to killing of the host cell by a penetration peg and utilization of cell content by the predator. Here, we report the 14.9-Mb S. fodiens draft genome sequence assembled into 9 large scaffolds and 13 minor scaffolds (<20 kb)., (Copyright © 2017 Junker et al.)
- Published
- 2017
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3. Developmental Growth Control Exerted via the Protein A Kinase Tpk2 in Ashbya gossypii.
- Author
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Wasserstrom L, Lengeler K, Walther A, and Wendland J
- Subjects
- Cyclic AMP-Dependent Protein Kinases genetics, Eremothecium enzymology, Eremothecium growth & development, Fungal Proteins genetics, Gene Deletion, Spores physiology, Cyclic AMP-Dependent Protein Kinases metabolism, Eremothecium genetics, Fungal Proteins metabolism, Spores genetics
- Abstract
Sporulation in Ashbya gossypii is induced by nutrient-limited conditions and leads to the formation of haploid spores. Using RNA-seq, we have determined a gene set induced upon sporulation, which bears considerable overlap with that of Saccharomyces cerevisiae but also contains A. gossypii-specific genes. Addition of cyclic AMP (cAMP) to nutrient-limited media blocks sporulation and represses the induction of sporulation specific genes. Deletion of the protein kinase A (PKA) catalytic subunits encoded by TPK1 and TPK2 showed reduced growth in tpk1 but enhanced growth in the tpk2 strain; however, both mutants sporulated well. Sporulation can be blocked by cAMP in tpk1 but not in tpk2 strains. Similarly, TPK2 acts at a second developmental switch promoting the break in spore dormancy. In S. cerevisiae, PKA phosphorylates and inhibits Msn2/4. The transcript profiles of the tpk1 and msn2/4 mutants were very similar to that of the wild type under sporulation conditions. However, deletion of the single A. gossypii MSN2/4 homolog generated a specific sporulation defect. We identified a set of genes involved in spore wall assembly that was downregulated in the msn2/4 mutant, particularly DIT2, suggesting that poor spore viability may be due to lysis of spores. Our results reveal specific functional differences between the two catalytic PKA subunits in A. gossypii and identified Tpk2 as the key A kinase that transduces developmental decisions of growth. Our data also suggest that Msn2/4 is involved only at a late step of sporulation in A. gossypii and is not a major regulator of IME1., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
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4. Lager yeast comes of age.
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Wendland J
- Subjects
- Biological Evolution, Chromosomes, Fungal genetics, High-Throughput Nucleotide Sequencing, Humans, Saccharomyces metabolism, Species Specificity, Beer microbiology, Fermentation, Genome, Fungal, Saccharomyces genetics
- Abstract
Alcoholic fermentations have accompanied human civilizations throughout our history. Lager yeasts have a several-century-long tradition of providing fresh beer with clean taste. The yeast strains used for lager beer fermentation have long been recognized as hybrids between two Saccharomyces species. We summarize the initial findings on this hybrid nature, the genomics/transcriptomics of lager yeasts, and established targets of strain improvements. Next-generation sequencing has provided fast access to yeast genomes. Its use in population genomics has uncovered many more hybridization events within Saccharomyces species, so that lager yeast hybrids are no longer the exception from the rule. These findings have led us to propose network evolution within Saccharomyces species. This "web of life" recognizes the ability of closely related species to exchange DNA and thus drain from a combined gene pool rather than be limited to a gene pool restricted by speciation. Within the domesticated lager yeasts, two groups, the Saaz and Frohberg groups, can be distinguished based on fermentation characteristics. Recent evidence suggests that these groups share an evolutionary history. We thus propose to refer to the Saaz group as Saccharomyces carlsbergensis and to the Frohberg group as Saccharomyces pastorianus based on their distinct genomes. New insight into the hybrid nature of lager yeast will provide novel directions for future strain improvement., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
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5. N-acetylglucosamine utilization by Saccharomyces cerevisiae based on expression of Candida albicans NAG genes.
- Author
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Wendland J, Schaub Y, and Walther A
- Subjects
- Aldose-Ketose Isomerases genetics, Aldose-Ketose Isomerases metabolism, Amidohydrolases genetics, Amidohydrolases metabolism, Bacterial Proteins genetics, Bacterial Proteins metabolism, Candida albicans genetics, Cloning, Molecular, Culture Media chemistry, Ethanol metabolism, Gene Expression, Monosaccharide Transport Proteins genetics, Monosaccharide Transport Proteins metabolism, Phosphotransferases (Alcohol Group Acceptor) genetics, Phosphotransferases (Alcohol Group Acceptor) metabolism, Recombinant Proteins genetics, Recombinant Proteins metabolism, Saccharomyces cerevisiae genetics, Acetylglucosamine metabolism, Candida albicans enzymology, Genes, Fungal, Genetic Engineering, Saccharomyces cerevisiae metabolism
- Abstract
Synthesis of chitin de novo from glucose involves a linear pathway in Saccharomyces cerevisiae. Several of the pathway genes, including GNA1, are essential. Genes for chitin catabolism are absent in S. cerevisiae. Therefore, S. cerevisiae cannot use chitin as a carbon source. Chitin is the second most abundant polysaccharide after cellulose and consists of N-acetylglucosamine (GlcNAc) moieties. Here, we have generated S. cerevisiae strains that are able to use GlcNAc as a carbon source by expressing four Candida albicans genes (NAG3 or its NAG4 paralog, NAG5, NAG2, and NAG1) encoding a GlcNAc permease, a GlcNAc kinase, a GlcNAc-6-phosphate deacetylase, and a glucosamine-6-phosphate deaminase, respectively. Expression of NAG3 and NAG5 or NAG4 and NAG5 in S. cerevisiae resulted in strains in which the otherwise-essential ScGNA1 could be deleted. These strains required the presence of GlcNAc in the medium, indicating that uptake of GlcNAc and its phosphorylation were achieved. Expression of all four NAG genes produced strains that could use GlcNAc as the sole carbon source for growth. Utilization of a GlcNAc catabolic pathway for bioethanol production using these strains was tested. However, fermentation was slow and yielded only minor amounts of ethanol (approximately 3.0 g/liter), suggesting that fructose-6-phosphate produced from GlcNAc under these conditions is largely consumed to maintain cellular functions and promote growth. Our results present the first step toward tapping a novel, renewable carbon source for biofuel production.
- Published
- 2009
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6. Candida albicans Sfl1 suppresses flocculation and filamentation.
- Author
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Bauer J and Wendland J
- Subjects
- Amino Acid Sequence, Candida albicans cytology, Candida albicans genetics, Candida albicans growth & development, Cell Nucleus metabolism, Flocculation, Fungal Proteins chemistry, Fungal Proteins genetics, Gene Deletion, Genes, Fungal, Green Fluorescent Proteins metabolism, Hyphae cytology, Molecular Sequence Data, Mutation genetics, Promoter Regions, Genetic genetics, Protein Transport, Recombinant Fusion Proteins metabolism, Sequence Analysis, Protein, Two-Hybrid System Techniques, Up-Regulation genetics, Candida albicans physiology, Fungal Proteins metabolism
- Abstract
Hyphal morphogenesis in Candida albicans is regulated by multiple pathways which act by either inducing or repressing filamentation. Most notably, Tup1, Nrg1, and Rfg1 are transcriptional repressors, while Efg1, Flo8, Cph1, and Czf1 can induce filamentation. Here, we present the functional analysis of CaSFL1, which encodes the C. albicans homolog of the Saccharomyces cerevisiae SFL1 (suppressor of flocculation) gene. Deletion of CaSFL1 results in flocculation (i.e., the formation of clumps) of yeast cells, which is most pronounced in minimal medium. The flocs contained hyphae already under noninducing conditions, and filamentation could be enhanced with hypha-inducing cues at 37 degrees C. Expression of SFL1 in a heterozygous mutant under the control of the CaMET3 promoter was shown to complement these defects and allowed switching between wild-type and mutant phenotypes. Interestingly, increased expression of SFL1 using a MET3prom-SFL1 construct prior to the induction of filamentation completely blocked germ tube formation. To localize Sfl1 in vivo, we generated a SFL1-GFP fusion. Sfl1-green fluorescent protein was found in the nucleus in both yeast cells and, to a lesser extent, hyphal cells. Using reverse transcription-PCR, we find an increased expression of ALS1, ALS3, HWP1, ECE1, and also FLO8. Our results suggest that Sfl1 functions in the repression of flocculation and filamentation and thus represents a novel negative regulator of C. albicans morphogenesis.
- Published
- 2007
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7. Candida albicans Rho-type GTPase-encoding genes required for polarized cell growth and cell separation.
- Author
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Dünkler A and Wendland J
- Subjects
- Candida albicans cytology, Cytokinesis, Fungal Proteins metabolism, Gene Deletion, Gene Expression, Hyphae growth & development, Models, Biological, Molecular Sequence Data, Morphogenesis, Mutation genetics, Phenotype, Protein Transport, Recombinant Fusion Proteins metabolism, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid, Candida albicans enzymology, Candida albicans growth & development, Cell Polarity, Genes, Fungal, rho GTP-Binding Proteins metabolism
- Abstract
Rho proteins are essential regulators of morphogenesis in eukaryotic cells. In this report, we investigate the role of two previously uncharacterized Rho proteins, encoded by the Candida albicans RHO3 (CaRHO3) and CaCRL1/CaRHO4 genes. The CaRHO3 gene was found to contain one intron. Promoter shutdown experiments using a MET3 promoter-controlled RHO3 revealed a strong cell polarity defect and a partially depolarized actin cytoskeleton. Hyphal growth after promoter shutdown was abolished in rho3 mutants even in the presence of a constitutively active ras1(G13V) allele, and existing germ tubes became swollen. Deletion of C. albicans RHO4 indicated that it is a nonessential gene and that rho4 mutants were phenotypically different from rho3. Two distinct phenotypes of rho4 cells were elongated cell morphology and an unexpected cell separation defect generating chains of cells. Colony morphology of crl1/rho4 resulted in a growth-dependent smooth (long cell cycle length) or wrinkled (short cell cycle length) phenotype. This phenotype was additionally dependent on the rho4 cell separation defect and was also found in a Cacht3 chitinase mutant that shows a strong cytokinesis defect. The overexpression of the endoglucanase encoding the ENG1 gene, but not CHT3, suppressed the cell separation defect of crl1/rho4 but could not suppress the cell elongation phenotype. C. albicans Crl1/Rho4 and Bnr1 both localize to septal sites in yeast and hyphal cells but not to the hyphal tip. Deletion of RHO4 and BNR1 produced similar morphological phenotypes. Based on the localization of Rho4 and on the rho4 mutant phenotype, we propose a model in which Rho4p may function as a regulator of cell polarity, breaking the initial axis of polarity found during early bud growth to promote the construction of a septum.
- Published
- 2007
- Full Text
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8. The SH3/PH domain protein AgBoi1/2 collaborates with the Rho-type GTPase AgRho3 to prevent nonpolar growth at hyphal tips of Ashbya gossypii.
- Author
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Knechtle P, Wendland J, and Philippsen P
- Subjects
- Alleles, Microfilament Proteins metabolism, Mutation genetics, Phenotype, Protein Binding, Protein Transport, Recombinant Fusion Proteins metabolism, Sequence Homology, Signal Transduction, Two-Hybrid System Techniques, Ascomycota cytology, Cell Polarity, Fungal Proteins chemistry, Fungal Proteins metabolism, Hyphae cytology, rho GTP-Binding Proteins metabolism, src Homology Domains
- Abstract
Unlike most other cells, hyphae of filamentous fungi permanently elongate and lack nonpolar growth phases. We identified AgBoi1/2p in the filamentous ascomycete Ashbya gossypii as a component required to prevent nonpolar growth at hyphal tips. Strains lacking AgBoi1/2p frequently show spherical enlargement at hyphal tips with concomitant depolarization of actin patches and loss of tip-located actin cables. These enlarged tips can repolarize and resume hyphal tip extension in the previous polarity axis. AgBoi1/2p permanently localizes to hyphal tips and transiently to sites of septation. Only the tip localization is important for sustained elongation of hyphae. In a yeast two-hybrid experiment, we identified the Rho-type GTPase AgRho3p as an interactor of AgBoi1/2p. AgRho3p is also required to prevent nonpolar growth at hyphal tips, and strains deleted for both AgBOI1/2 and AgRHO3 phenocopied the respective single-deletion strains, demonstrating that AgBoi1/2p and AgRho3p function in a common pathway. Monitoring the polarisome of growing hyphae using AgSpa2p fused to the green fluorescent protein as a marker, we found that polarisome disassembly precedes the onset of nonpolar growth in strains lacking AgBoi1/2p or AgRho3p. AgRho3p locked in its GTP-bound form interacts with the Rho-binding domain of the polarisome-associated formin AgBni1p, implying that AgRho3p has the capacity to directly activate formin-driven actin cable nucleation. We conclude that AgBoi1/2p and AgRho3p support polarisome-mediated actin cable formation at hyphal tips, thereby ensuring permanent polar tip growth.
- Published
- 2006
- Full Text
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9. Ras1-induced hyphal development in Candida albicans requires the formin Bni1.
- Author
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Martin R, Walther A, and Wendland J
- Subjects
- Actins metabolism, Cell Polarity, Cyclic AMP metabolism, Cytoskeleton metabolism, Endocytosis, Fungal Proteins genetics, Hyphae ultrastructure, Microfilament Proteins genetics, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Saccharomyces cerevisiae Proteins genetics, Signal Transduction, Time Factors, Vacuoles metabolism, Vacuoles ultrastructure, ras Proteins genetics, Candida albicans cytology, Candida albicans physiology, Fungal Proteins metabolism, Hyphae metabolism, Microfilament Proteins metabolism, Saccharomyces cerevisiae Proteins metabolism, ras Proteins metabolism
- Abstract
Formins are downstream effector proteins of Rho-type GTPases and are involved in the organization of the actin cytoskeleton and actin cable assembly at sites of polarized cell growth. Here we show using in vivo time-lapse microscopy that deletion of the Candida albicans formin homolog BNI1 results in polarity defects during yeast growth and hyphal stages. Deletion of the second C. albicans formin, BNR1, resulted in elongated yeast cells with cell separation defects but did not interfere with the ability of bnr1 cells to initiate and maintain polarized hyphal growth. Yeast bni1 cells were swollen, showed an increased random budding pattern, and had a severe defect in cytokinesis, with enlarged bud necks. Induction of hyphal development in bni1 cells resulted in germ tube formation but was halted at the step of polarity maintenance. Bni1-green fluorescent protein is found persistently at the hyphal tip and colocalizes with a structure resembling the Spitzenkörper of true filamentous fungi. Introduction of constitutively active ras1G13V in the bni1 strain or addition of cyclic AMP to the growth medium did not bypass bni1 hyphal growth defects. Similarly, these agents were not able to suppress hyphal growth defects in the wal1 mutant which is lacking the Wiskott-Aldrich syndrome protein (WASP) homolog. These results suggest that the maintenance of polarized hyphal growth in C. albicans requires coordinated regulation of two actin cytoskeletal pathways, including formin-mediated secretion and WASP-dependent endocytosis.
- Published
- 2005
- Full Text
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10. Deletion of the dynein heavy-chain gene DYN1 leads to aberrant nuclear positioning and defective hyphal development in Candida albicans.
- Author
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Martin R, Walther A, and Wendland J
- Subjects
- Active Transport, Cell Nucleus, Alleles, Candida albicans metabolism, Cell Movement, Cell Survival, Cytoplasm metabolism, DNA Primers chemistry, Genotype, Green Fluorescent Proteins metabolism, Heterozygote, Microscopy, Fluorescence, Microscopy, Video, Mitosis, Models, Genetic, Mutation, Open Reading Frames, Phenotype, Promoter Regions, Genetic, Recombinant Fusion Proteins metabolism, Spindle Apparatus metabolism, Time Factors, Candida albicans genetics, Cell Nucleus metabolism, Dyneins genetics, Gene Deletion
- Abstract
Cytoplasmic dynein is a microtubule-associated minus-end-directed motor protein. CaDYN1 encodes the single dynein heavy-chain gene of Candida albicans. The open reading frames of both alleles of CaDYN1 were completely deleted via a PCR-based approach. Cadyn1 mutants are viable but grow more slowly than the wild type. In vivo time-lapse microscopy was used to compare growth of wild-type (SC5314) and dyn1 mutant strains during yeast growth and after hyphal induction. During yeast-like growth, Cadyn1 strains formed chains of cells. Chromosomal TUB1-GFP and HHF1-GFP alleles were used both in wild-type and mutant strains to monitor the orientation of mitotic spindles and nuclear positioning in C. albicans. In vivo fluorescence time-lapse analyses with HHF1-GFP over several generations indicated defects in dyn1 cells in the realignment of spindles with the mother-daughter axis of yeast cells compared to that of the wild type. Mitosis in the dyn1 mutant, in contrast to that of wild-type yeast cells, was very frequently completed in the mother cells. Nevertheless, daughter nuclei were faithfully transported into the daughter cells, resulting in only a small number of multinucleate cells. Cadyn1 mutant strains responded to hypha-inducing media containing l-proline or serum with initial germ tube formation. Elongation of the hyphal tubes eventually came to a halt, and these tubes showed a defect in the tipward localization of nuclei. Using a heterozygous DYN1/dyn1 strain in which the remaining copy was controlled by the regulatable MAL2 promoter, we could switch between wild-type and mutant phenotypes depending on the carbon source, indicating that the observed mutant phenotypes were solely due to deletion of DYN1.
- Published
- 2004
- Full Text
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11. Polarized hyphal growth in Candida albicans requires the Wiskott-Aldrich Syndrome protein homolog Wal1p.
- Author
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Walther A and Wendland J
- Subjects
- Actins metabolism, Amino Acid Sequence, Candida albicans cytology, Candida albicans genetics, Cell Cycle, Cell Polarity, Cell Wall ultrastructure, Endocytosis, Fungal Proteins genetics, Hyphae growth & development, Hyphae ultrastructure, Microscopy, Fluorescence, Molecular Sequence Data, Mutation, Proteins genetics, Proteins metabolism, Pyridinium Compounds analysis, Pyridinium Compounds metabolism, Quaternary Ammonium Compounds analysis, Quaternary Ammonium Compounds metabolism, Sequence Alignment, Vacuoles ultrastructure, Wiskott-Aldrich Syndrome Protein, Candida albicans growth & development, Fungal Proteins physiology, Proteins physiology
- Abstract
The yeast-to-hypha transition is a key feature in the cell biology of the dimorphic human fungal pathogen Candida albicans. Reorganization of the actin cytoskeleton is required for this dimorphic switch in Candida. We show that C. albicans WAL1 mutants with both copies of the Wiskott-Aldrich syndrome protein (WASP) homolog deleted do not form hyphae under all inducing conditions tested. Growth of the wild-type and wal1 mutant strains was monitored by in vivo time-lapse microscopy both during yeast-like growth and under hypha-inducing conditions. Isotropic bud growth produced round wal1 cells and unusual mother cell growth. Defects in the organization of the actin cytoskeleton resulted in the random localization of actin patches. Furthermore, wal1 cells exhibited defects in the endocytosis of the lipophilic dye FM4-64, contained increased numbers of vacuoles compared to the wild type, and showed defects in bud site selection. Under hypha-inducing conditions wal1 cells were able to initiate polarized morphogenesis, which, however, resulted in the formation of pseudohyphal cells. Green fluorescent protein (GFP)-tagged Wal1p showed patch-like localization in emerging daughter cells during the yeast growth phase and at the hyphal tips under hypha-inducing conditions. Wal1p-GFP localization largely overlapped with that of actin. Our results demonstrate that Wal1p is required for the organization of the actin cytoskeleton and hyphal morphogenesis in C. albicans as well as for endocytosis and vacuole morphology.
- Published
- 2004
- Full Text
- View/download PDF
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