A5029971514- Cellular Mechanics and Interactions
- Microtubule and mitosis dynamics
- Bacterial Genetics and Biotechnology
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Cell Image Analysis Techniques
- Advanced Fluorescence Microscopy Techniques
- Bioinformatics and Genomic Networks
- Bacteriophages and microbial interactions
- Fungal and yeast genetics research
- RNA and protein synthesis mechanisms
- Legionella and Acanthamoeba research
- Gene Regulatory Network Analysis
- Biocrusts and Microbial Ecology
- Genetics, Aging, and Longevity in Model Organisms
- Plant Reproductive Biology
- Vibrio bacteria research studies
- Evolutionary Game Theory and Cooperation
- Microbial Metabolic Engineering and Bioproduction
- Skin and Cellular Biology Research
- Evolution and Genetic Dynamics
- 3D Printing in Biomedical Research
- Bacterial biofilms and quorum sensing
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- CRISPR and Genetic Engineering
Baylor College of Medicine
2010-2020
Welch Foundation
2020
Rice University
2008-2013
The University of Tokyo
2010
University of California, San Diego
1984-2004
Osaka University
2004
University of Tsukuba
2004
Institute of Developmental Physiology
2002
Max Planck Institute of Biochemistry
1998
University of Cologne
1998
Introduction of restriction enzyme along with linearized plasmid results in integration DNA at genomic sites a high proportion the resulting transformants. We have found that electroporating BamHI or EcoRI together pyr5-6 plasmids cut same stimulates efficiency transformation Dictyostelium discoideum more than 20-fold over rate seen when alone is introduced. Restriction enzyme-mediated generates insertions into an apparently random manner, some which cause mutations. About 1 400...
Social amoebae feed on bacteria in the soil but aggregate when starved to form a migrating slug. We describe previously unknown cell type social amoeba, which appears provide detoxification and immune-like functions we term sentinel (S) cells. S cells were observed engulf sequester toxins while circulating within slug, eventually being sloughed off. A Toll/interleukin-1 receptor (TIR) domain protein, TirA, was also required for some vegetative live bacteria. This apparent innate immune...
Abstract Background Evolutionarily divergent organisms often share developmental anatomies despite vast differences between their genome sequences. The social amoebae Dictyostelium discoideum and purpureum have similar morphologies although genomes are as those of man jawed fish. Results Here we show that the anatomical similarities accompanied by extensive transcriptome conservation. Using RNA sequencing compared abundance regulation all transcripts in two species. In both species, most...
Abstract Background The social amoebae (Dictyostelia) are a diverse group of Amoebozoa that achieve multicellularity by aggregation and undergo morphogenesis into fruiting bodies with terminally differentiated spores stalk cells. There four groups dictyostelids, the most derived being contains model species Dictyostelium discoideum . Results We have produced draft genome sequence another dictyostelid, purpureum , compare it to D. genome. assembly (8.41 × coverage) comprises 799 scaffolds...
Free-living cells of the social amoebae Dictyostelium discoideum can aggregate and develop into multicellular fruiting bodies in which many die altruistically as they become stalk that support surviving spores. exhibit kin discrimination--a potential defense against cheaters, sporulate without contributing to stalk. Kin discrimination depends on strain relatedness, polymorphic genes tgrB1 tgrC1 are components mechanism. Here, we demonstrate a direct role for these discrimination. We show...
Abstract Extracellular traps (ETs) from neutrophils are reticulated nets of DNA decorated with anti-microbial granules, and capable trapping killing extracellular pathogens. Various phagocytes mammals invertebrates produce ETs, however, the evolutionary history this DNA-based host defence strategy is unclear. Here we report that Sentinel (S) cells multicellular slug stage social amoeba Dictyostelium discoideum ETs upon stimulation bacteria or lipopolysaccharide in a reactive oxygen...
Adenylyl cyclase in Dictyostelium, as higher eukaryotes, is activated through G protein-coupled receptors. Insertional mutagenesis into a gene designated dagA resulted cells that cannot activate adenylyl cyclase, but have otherwise normal responses to exogenous cAMP. Neither cAMP treatment of intact nor GTP gamma S lysates stimulates activity mutants. A cytosolic protein activates CRAC, has been previously identified. We trace the signaling defect dagA- absence and we demonstrate structural...
Analysis of a developmental mutant in Dictyostelium discoideum which is unable to initiate morphogenesis has shown that protein kinase the MAP kinase/ERK family affects relay cAMP chemotactic signal and cell differentiation. Strains locus encoding ERK2 disrupted respond pulse by synthesizing cGMP normally but show little synthesis cAMP. Since cells lacking contain normal levels both cytosolic regulator adenylyl cyclase (CRAC) manganese-activatable cyclase, it appears this important for...
Self-regulating systems often use robust oscillatory circuits. One such system controls the chemotactic signaling mechanism of Dictyostelium, where pulses adenosine 3',5'-monophosphate (cAMP) are generated with a periodicity 7 minutes. We have observed spontaneous oscillations in activation mitogen-activated protein (MAP) kinase ERK2 that occur phase peaks cAMP, and we show modulates cAMP levels through phosphodiesterase RegA. Computer modeling simulations underlying circuit faithfully...
The asg mutants of Myxococcus xanthus fail to produce a set related substances called A-factor. A-factor is released into the medium and required early in fruiting body development. Lacking A-factor, are defective aggregation, sporulation, expression most genes whose products appear later than 1 h after development induced by starvation. Previous work has shown that these defects reversed when developing wild-type cells, added mutant cells. Part material conditioned with activity heat stable...
Mutations in any of three asg (A-signalling) loci cause fruiting body development Myxococcus xanthus to arrest at about the 2-h stage. Development can be restored mutants by addition conditioned buffer which wild-type cells have been developing or A-factor purified from buffer. Two forms identified: heat-stable A-factor, is composed amino acids and peptides, heat-labile consists least two proteases. found rough proportion cell density. As decreasing amounts either form are added,...
Strain AK127 is a developmental mutant of Dictyostelium discoideum that was isolated by restriction enzyme-mediated integration (REMI). Mutant cells aggregate normally but are unable to proceed past the loose stage. The cloned gene, lagC (loose C), encodes novel protein 98 kD contains an amino-terminal signal sequence and putative carboxy-terminal transmembrane domain. strain shows no detectable transcript upon Northern analysis, indicating observed phenotype null allele. Expression cDNA in...
ABSTRACT When Dictyostelium cells starve they arrest their growth and induce the expression of genes necessary for development. We have identified characterized a protein kinase, YakA, that is essential proper regulation both events. Amino acid sequence functional similarities indicate YakA homolog Yak1p, growth-regulating kinase in S. cerevisiae. Purified expressed E. coli able to phosphorylate myelin basic protein. YakA-null are smaller cell cycle accelerated relative wild-type cells....
A distinct feature of development in the simple eukaryote Dictyostelium discoideum is an aggregative transition from a unicellular to multicellular phase. Using genome-wide transcriptional analysis we show that this accompanied by dramatic change expression more than 25% genes genome. We also transcription patterns these are not sensitive strain or nutritional history, indicating robust physiological process stereotypical events. Analysis two differentiated cell types, spores and stalk...
The asg mutants of Myxococcus xanthus are defective in the production an extracellular substance, called A-factor, that is required for expression a set fruiting body-specific genes. A-factor released by wild-type cells (asg+) after 1 to 2 h development. When added mutant cells, it restores their A-factor-dependent Rescue beta-galactosidase carrying lacZ transcriptional fusion (omega 4521) was used assay activity. According this assay, two types substances with activity present conditioned...
ABSTRACT When nutrients are depleted, Dictyostelium cells undergo cell cycle arrest and initiate a developmental program that ensures survival. The YakA protein kinase governs this transition by regulating the cycle, repressing growth-phase genes inducing genes. mutants have shortened do not development. A suppressor of yakA reverses most defects yakA− cells, but none their growth was identified. inactivated gene, pufA, encodes member Puf family translational regulators. Upon starvation,...
Adenosine 3′,5′-monophosphate (cAMP) and cAMP-dependent protein kinase (PKA) are regulators of development in many organisms. Dictyostelium uses cAMP as an extracellular chemoattractant intracellular signal for differentiation. Cells that mutant adenylyl cyclase do not develop. Moderate expression the catalytic subunit PKA cyclase–null cells led to near-normal without detectable accumulation cAMP. These results suggest all signaling is effected through signals other than coordinate...