A5044562249- Bacterial Genetics and Biotechnology
- Bacteriophages and microbial interactions
- RNA and protein synthesis mechanisms
- Genomics and Phylogenetic Studies
- Bacterial biofilms and quorum sensing
- Legume Nitrogen Fixing Symbiosis
- Microbial Natural Products and Biosynthesis
- Enzyme Structure and Function
- Bacterial Identification and Susceptibility Testing
- Microbial Community Ecology and Physiology
- Antimicrobial Resistance in Staphylococcus
- Antibiotic Resistance in Bacteria
- Antimicrobial Peptides and Activities
- Plant Virus Research Studies
- CRISPR and Genetic Engineering
- Advanced Electron Microscopy Techniques and Applications
- DNA Repair Mechanisms
- Microbial Metabolic Engineering and Bioproduction
- DNA and Nucleic Acid Chemistry
- Cellular transport and secretion
- Gut microbiota and health
- Bacillus and Francisella bacterial research
- Photosynthetic Processes and Mechanisms
- Cell Image Analysis Techniques
- Protein Structure and Dynamics
University of California, San Diego
2016-2025
Emory University
2004
Harvard University Press
1999
Harvard University
1993-1998
Integrating the governing chemistry with genomics and phenotypes of microbial colonies has been a “holy grail” in microbiology. This work describes highly sensitive, broadly applicable, cost-effective approach that allows metabolic profiling live directly from Petri dish without any sample preparation. Nanospray desorption electrospray ionization mass spectrometry (MS), combined alignment MS data molecular networking, enabled monitoring metabolite production diverse bacterial genera,...
Identifying the mechanism of action for antibacterial compounds is essential understanding how bacteria interact with one another and other cell types antibiotic discovery efforts, but determining a compound's remains serious challenge that limits both basic research programs. Here, we show bacterial cytological profiling (BCP) rapid powerful approach identifying cellular pathway affected by molecules. BCP can distinguish between inhibitors affect different pathways as well targets within...
We observed the assembly of a nucleus-like structure in bacteria during viral infection. Using fluorescence microscopy and cryo-electron tomography, we showed that Pseudomonas chlororaphis phage 201φ2-1 assembled compartment separated DNA from cytoplasm. The was centered by bipolar tubulin-based spindle, it segregated bacterial proteins according to function. Proteins involved replication transcription localized inside compartment, whereas translation nucleotide synthesis outside. Later...
The ability to correlate the production of specialized metabolites genetic capacity organism that produces such molecules has become an invaluable tool in aiding discovery biotechnologically applicable molecules. Here, we accomplish this task by matching molecular families with gene cluster families, making these correlations 60 microbes at one time instead connecting molecule a time, as how it is traditionally done. We can through use nanospray desorption electrospray ionization MS/MS,...
At the onset of sporulation in Bacillus subtilis , two potential division sites are assembled at each pole, one which will be used to synthesize asymmetrically positioned septum. Using vital stain FM 4‐64 label plasma membrane living cells, we examined fate these wild‐type cells and found that, immediately after formation septum, a partial septum was frequently synthesized within mother cell second site. time‐lapse deconvolution microscopy, were able watch septa first appear then disappear...
A universally conserved event in cell division is the formation of a cytokinetic ring at future site division. In bacterium Escherichia coli , this formed by essential protein FtsZ. We have used immunofluorescence microscopy to show that FtsZ assembles early cycle, suggesting constriction regulated and supporting view serves as bacterial cytoskeleton. Assembly rings was heterogeneously affected an ftsI temperature-sensitive mutant grown nonpermissive temperature, some filaments displaying...
During bacterial cannibalism, a differentiated subpopulation harvests nutrients from their genetically identical siblings to allow continued growth in nutrient-limited conditions. Hypothesis-driven imaging mass spectrometry (IMS) was used identify metabolites active Bacillus subtilis cannibalism system which sporulating cells lyse nonsporulating siblings. Two candidate molecules with sequences matching the products of skfA and sdpC , genes for proposed cannibalistic factors sporulation...
During λ infections, the holin S105 accumulates harmlessly in membrane until, at an allele-specific time, suddenly triggering to form irregular holes of unprecedented size (>300 nm), releasing endolysin from cytoplasm, resulting lysis within seconds. Here we used a functional S105–GFP chimera and real-time deconvolution fluorescence microscopy show that fusion accumulated uniformly distributed fashion, until suddenly, 1 min, it formed aggregates, or rafts, time lethal triggering....
ABSTRACT The assembly of the cell division machinery at midcell is a critical step cytokinesis. Many rod-shaped bacteria position septa using nucleoid occlusion, which prevents over chromosome, and Min system, near poles. Here we examined in vivo Bacillus subtilis MinCD targeting proteins DivIVA, peripheral membrane protein that preferentially localizes to negatively curved membranes resembles eukaryotic tropomyosins, MinJ, recruits DivIVA. We used structured illumination microscopy...
Microbial competition exists in the general environment, such as soil or aquatic habitats, upon within unicellular multicellular eukaryotic life forms. The molecular actions that govern microbial competition, leading to niche establishment and monopolization, remain undetermined. emerging technology of imaging mass spectrometry (IMS) enabled observation there is directionality metabolic output organism Bacillus subtilis when co-cultured with Staphylococcus aureus . directionally released...
Summary Bacillus subtilis SDP is a peptide toxin that kills cells outside the biofilm to support continued growth. We show purified acts like endogenously produced SDP; it delays sporulation, and SdpI immunity protein confers resistance. variety of Gram‐positive bacteria in phylum Firmicutes, as well Escherichia coli with compromised outer membrane, suggesting participates defence B. against cannibalism. Fluorescence microscopy reveals effect on differs from nisin, nigericin, valinomycin...
Summary While vegetative B acillus subtilis cells and mature spores are both surrounded by a thick layer of peptidoglycan ( PG , polymer glycan strands cross‐linked peptide bridges), it has remained unclear whether surrounds prespores during engulfment. To clarify this issue, we generated slender Δ ponA mutant that enabled high‐resolution electron cryotomographic imaging. Three‐dimensional reconstructions whole in near‐native states revealed thin ‐like extending from the lateral cell wall...
We recently discovered that some bacteriophages establish a nucleus-like replication compartment (phage nucleus), but the core genes define nucleus-based phage and their phylogenetic distribution were still to be determined. Here, we show phages encoding major nucleus protein chimallin share 72 conserved encoded within seven gene blocks. Of these, 21 are unique nucleus-forming phage, all one of these encode proteins unknown function. propose comprise novel viral family term Chimalliviridae....
Targeting proteins to specific subcellular destinations is essential in prokaryotes, eukaryotes, and the viruses that infect them. Chimalliviridae phages encapsulate their genomes a nucleus-like replication compartment composed of protein chimallin (ChmA) excludes ribosomes decouples transcription from translation. These selectively partition between phage nucleus bacterial cytoplasm. Currently, genes signals govern selective import into are unknown. Here, we identify two components this...
Abstract The bacterium Bacillus subtilis undergoes asymmetric cell division during sporulation, producing a mother and smaller forespore connected by the SpoIIQ-SpoIIIA (or Q-A) channel. two cells differentiate metabolically, becomes dependent on for essential building blocks. Here, we investigate metabolic interactions between using genome-scale expression models as well experiments. Our results indicate that nucleotides are synthesized in transported form of nucleoside di- or...
We have adapted immunofluorescence microscopy for use in Bacillus subtilis and employed this procedure visualizing cell-specific gene expression at early to intermediate stages of sporulation. Sporangia were doubly stained with propidium iodide visualize the forespore mother cell nucleoids fluorescein-conjugated antibodies location beta-galactosidase produced under control sporulation RNA polymerase sigma factors E F. In confirmation extension earlier reports, we found that a lacZ fusion was...
Asymmetric division in Bacillus subtilis generates progeny cells with dissimilar fates. SpoIIE, a membrane protein required for the establishment of cell type, was shown to localize near sites potential polar division. SpoIIE initially localizes bipolar pattern, coalescing at marks envelope which asymmetric can take place. Then, during division, becomes restricted septum and is lost from distal pole. Thus, when complete, sits boundary between it dictates fate by activation cell-specific...
Shortly after the synthesis of two cells required for sporulation in Bacillus subtilis , membranes larger mother cell begin to migrate around and engulf smaller forespore cell. At completion this process leading edges migrating membrane meet fuse, releasing into cytoplasm. We developed a fluorescent stain-based assay fusion event, we isolated mutants defective final stages engulfment or fusion. All had defects spoIIIE, which is translocation chromosome across polar septum. one spoIIIE mutant...
We describe the application of immunofluorescence microscopy to visualization subcellular localization proteins involved in coat morphogenesis and chromosome packaging during process sporulation Bacillus subtilis . In confirmation extension previous findings, we show that SpolVA, which is responsible for guiding formation surface outer membrane surrounds developing spore, assembles into a shell located close or on this enveloping membrane. CotE, layer coat, second apparently larger diameter....
Division site selection in rod-shaped bacteria depends on nucleoid occlusion, which prevents division over the chromosome and MinCD, prevent at poles. MinD is thought to localize MinC cell poles where it FtsZ assembly. Time-lapse microscopy demonstrates that Bacillus subtilis transient polar rings assemble adjacent recently completed septa minCD strains these persist are used for division, producing a minicell. This suggests acts when proteins released from newly their immediate reassembly...