The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Lucy Shapiro - One of the best experts on this subject based on the ideXlab platform.
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Spatial organization and dynamics of RNase E and ribosomes in Caulobacter crescentus.
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Camille Bayas, Lucy Shapiro, Jared M Schrader, Jiarui Wang, Marissa K. Lee, W. E. MoernerAbstract:We report the dynamic spatial organization of Caulobacter crescentus RNase E (RNA degradosome) and ribosomal protein L1 (ribosome) using 3D single-particle tracking and superresolution microscopy. RNase E formed clusters along the central axis of the cell, while weak clusters of ribosomal protein L1 were deployed throughout the cytoplasm. These results contrast with RNase E and ribosome distribution in Escherichia coli, where RNase E colocalizes with the cytoplasmic membrane and ribosomes accumulate in polar nucleoid-free zones. For both RNase E and ribosomes in Caulobacter, we observed a decrease in confinement and clustering upon transcription inhibition and subsequent depletion of nascent RNA, suggesting that RNA substrate availability for processing, degradation, and translation facilitates confinement and clustering. Importantly, RNase E cluster positions correlated with the subcellular location of chromosomal loci of two highly transcribed rRNA genes, suggesting that RNase E’s function in rRNA processing occurs at the site of rRNA synthesis. Thus, components of the RNA degradosome and ribosome assembly are spatiotemporally organized in Caulobacter, with chromosomal readout serving as the template for this organization.
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Spatial organization and dynamics of RNase E and ribosomes in Caulobacter crescentus
2017Co-Authors: Camille Bayas, Lucy Shapiro, Jared M Schrader, Jiarui Wang, Marissa K. Lee, W. E. MoernerAbstract:We report the dynamic spatial organization of Caulobacter crescentus RNase E (RNA degradosome) and ribosomal protein L1 (ribosome) using 3D single particle tracking and super-resolution microscopy. RNase E formed clusters along the central axis of the cell, while weak clusters of ribosomal protein L1 were deployed throughout the cytoplasm. These results contrast with RNase E and ribosome distribution in E. coli , where RNase E co-localizes with the cytoplasmic membrane and ribosomes accumulate in polar nucleoid-free zones. For both RNase E and ribosomes in Caulobacter , we observed a decrease in confinement and clustering upon transcription inhibition and subsequent depletion of nascent RNA, suggesting that RNA substrate availability for processing, degradation, and translation facilitates confinement and clustering. Moreover, RNase E cluster positions correlate with the subcellular location of chromosomal loci of two highly transcribed ribosomal RNA genes, suggesting that RNase E9s function in ribosomal RNA processing occurs at the site of rRNA synthesis. Thus, components of the RNA degradosome and ribosome assembly are spatiotemporally organized in Caulobacter , with chromosomal readout serving as the template for this organization.
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Environmental Calcium Controls Alternate Physical States of the Caulobacter Surface Layer
Biophysical journal, 2017Co-Authors: Jonathan Herrmann, John Smit, Lucy Shapiro, John F. Nomellini, Fatemeh Jabbarpour, Paul G. Bargar, Thomas J. Lane, Thomas M. Weiss, Soichi WakatsukiAbstract:Surface layers (S-layers) are paracrystalline, proteinaceous structures found in most archaea and many bacteria. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. We report that the S-layer of Caulobacter crescentus exhibits calcium-mediated structural plasticity, switching irreversibly between an amorphous aggregate state and the crystalline state. This finding invalidates the common assumption that S-layers serve only as static wall-like structures. In vitro, the Caulobacter S-layer protein, RsaA, enters the aggregate state at physiological temperatures and low divalent calcium ion concentrations. At higher concentrations, calcium ions stabilize monomeric RsaA, which can then transition to the two-dimensional crystalline state. Caulobacter requires micromolar concentrations of calcium for normal growth and development. Without an S-layer, Caulobacter is even more sensitive to changes in environmental calcium concentration. Therefore, this structurally dynamic S-layer responds to environmental conditions as an ion sensor and protects Caulobacter from calcium deficiency stress, a unique mechanism of bacterial adaptation. These findings provide a biochemical and physiological basis for RsaA's calcium-binding behavior, which extends far beyond calcium's commonly accepted role in aiding S-layer biogenesis or oligomerization and demonstrates a connection to cellular fitness.
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cell cycle progression in Caulobacter requires a nucleoid associated protein with high at sequence recognition
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Dante P Ricci, Harley H Mcadams, Keren Lasker, David L Dill, Michael D Melfi, Lucy ShapiroAbstract:Faithful cell cycle progression in the dimorphic bacterium Caulobacter crescentus requires spatiotemporal regulation of gene expression and cell pole differentiation. We discovered an essential DNA-associated protein, GapR, that is required for Caulobacter growth and asymmetric division. GapR interacts with adenine and thymine (AT)-rich chromosomal loci, associates with the promoter regions of cell cycle-regulated genes, and shares hundreds of recognition sites in common with known master regulators of cell cycle-dependent gene expression. GapR target loci are especially enriched in binding sites for the transcription factors GcrA and CtrA and overlap with nearly all of the binding sites for MucR1, a regulator that controls the establishment of swarmer cell fate. Despite constitutive synthesis, GapR accumulates preferentially in the swarmer compartment of the predivisional cell. Homologs of GapR, which are ubiquitous among the α-proteobacteria and are encoded on multiple bacteriophage genomes, also accumulate in the predivisional cell swarmer compartment when expressed in Caulobacter The Escherichia coli nucleoid-associated protein H-NS, like GapR, selectively associates with AT-rich DNA, yet it does not localize preferentially to the swarmer compartment when expressed exogenously in Caulobacter, suggesting that recognition of AT-rich DNA is not sufficient for the asymmetric accumulation of GapR. Further, GapR does not silence the expression of H-NS target genes when expressed in E. coli, suggesting that GapR and H-NS have distinct functions. We propose that Caulobacter has co-opted a nucleoid-associated protein with high AT recognition to serve as a mediator of cell cycle progression.
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CauloBrowser: A systems biology resource for Caulobacter crescentus.
Nucleic acids research, 2015Co-Authors: Keren Lasker, Harley H Mcadams, Jared M Schrader, Yifei Men, Tyler Marshik, David L Dill, Lucy ShapiroAbstract:Caulobacter crescentus is a premier model organism for studying the molecular basis of cellular asymmetry. The Caulobacter community has generated a wealth of high-throughput spatiotemporal databases including data from gene expression profiling experiments (microarrays, RNA-seq, ChIP-seq, ribosome profiling, LC-ms proteomics), gene essentiality studies (Tn-seq), genome wide protein localization studies, and global chromosome methylation analyses (SMRT sequencing). A major challenge involves the integration of these diverse data sets into one comprehensive community resource. To address this need, we have generated CauloBrowser (www.caulobrowser.org), an online resource for Caulobacter studies. This site provides a user-friendly interface for quickly searching genes of interest and downloading genome-wide results. Search results about individual genes are displayed as tables, graphs of time resolved expression profiles, and schematics of protein localization throughout the cell cycle. In addition, the site provides a genome viewer that enables customizable visualization of all published high-throughput genomic data. The depth and diversity of data sets collected by the Caulobacter community makes CauloBrowser a unique and valuable systems biology resource.
John Smit - One of the best experts on this subject based on the ideXlab platform.
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Environmental Calcium Controls Alternate Physical States of the Caulobacter Surface Layer
Biophysical journal, 2017Co-Authors: Jonathan Herrmann, John Smit, Lucy Shapiro, John F. Nomellini, Fatemeh Jabbarpour, Paul G. Bargar, Thomas J. Lane, Thomas M. Weiss, Soichi WakatsukiAbstract:Surface layers (S-layers) are paracrystalline, proteinaceous structures found in most archaea and many bacteria. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. We report that the S-layer of Caulobacter crescentus exhibits calcium-mediated structural plasticity, switching irreversibly between an amorphous aggregate state and the crystalline state. This finding invalidates the common assumption that S-layers serve only as static wall-like structures. In vitro, the Caulobacter S-layer protein, RsaA, enters the aggregate state at physiological temperatures and low divalent calcium ion concentrations. At higher concentrations, calcium ions stabilize monomeric RsaA, which can then transition to the two-dimensional crystalline state. Caulobacter requires micromolar concentrations of calcium for normal growth and development. Without an S-layer, Caulobacter is even more sensitive to changes in environmental calcium concentration. Therefore, this structurally dynamic S-layer responds to environmental conditions as an ion sensor and protects Caulobacter from calcium deficiency stress, a unique mechanism of bacterial adaptation. These findings provide a biochemical and physiological basis for RsaA's calcium-binding behavior, which extends far beyond calcium's commonly accepted role in aiding S-layer biogenesis or oligomerization and demonstrates a connection to cellular fitness.
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Phylogeny and polyphasic taxonomy of Caulobacter species. Proposal of Maricaulis gen. nov. with Maricaulis maris (Poindexter) comb. nov. as the type species, and emended description of the genera Brevundimonas and Caulobacter.
International Journal of Systematic and Evolutionary Microbiology, 1999Co-Authors: Wolf-rainer Abraham, Sabine Lindholst, Ruprecht Christ, Antonio Bennasar, Edward R B Moore, Carsten Strompl, Brian J Tindall, Holger Meyer, Marc Vancanneyt, John SmitAbstract:The genus Caulobacter is composed of prosthecate bacteria often specialized for oligotrophic environments. The taxonomy of Caulobacter has relied primarily upon morphological criteria: A strain that visually appeared to be a member of the Caulobacter has generally been called one without challenge. A polyphasic approach, comprising 16S rDNA sequencing, profiling restriction fragments of 16S-23S rDNA interspacer regions, lipid analysis, immunological profiling and salt tolerance characterizations, was used to clarify the taxonomy of 76 strains of the genera Caulobacter, Brevundimonas, Hyphomonas and Mycoplana. The described species of the genus Caulobacter formed a paraphyletic group with Caulobacter henricii, Caulobacter fusiformis, Caulobacter vibrioides and Mycoplana segnis (Caulobacter segnis comb, nov.) belonging to Caulobacter sensu stricto. Caulobacter bacteroides (Brevundimonas bacteroides comb, nov.), C. henricii subsp. aurantiacus (Brevundimonas aurantiaca comb, nov.), Caulobacter intermedius (Brevundimonas intermedia comb. nov.), Caulobacter subvibrioides (Brevundimonas subvibrioides comb. nov.), C. subvibrioides subsp. albus (Brevundimonas alba comb. nov.), Caulobacter variabilis (Brevundimonas variabilis comb. nov.) and Mycoplana bullata belong to the genus Brevundimonas. The halophilic species Caulobacter maris and Caulobacter halobacteroides are different from these two genera and form the genus Maricaulis gen. nov. with Maricaulis maris as the type specis Caulobacter leidyia was observed to cluster with species of the genus Sphingomonas. Caulobacter crescentus is synonymous with C.vibrioides and C. halobacteroides is synonymous with Maricaulis maris as determined by these analyses and DNA-DNA hybridization. Biomarkers discerning these different genera were determined. The necessary recombinations have been proposed and a description of Maricaulis is presented.
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Phylogeny and polyphasic taxonomy of Caulobacter species. Proposal of Maricaulis gen. nov. with Maricaulis maris (Poindexter) comb. nov. as the type species, and emended description of the genera Brevundimonas and Caulobacter.
International journal of systematic bacteriology, 1999Co-Authors: Wolf-rainer Abraham, Sabine Lindholst, Ruprecht Christ, Antonio Bennasar, Edward R B Moore, Carsten Strompl, Brian J Tindall, Holger Meyer, Marc Vancanneyt, John SmitAbstract:The genus Caulobacter is composed of prosthecate bacteria often specialized for oligotrophic environments. The taxonomy of Caulobacter has relied primarily upon morphological criteria: a strain that visually appeared to be a member of the Caulobacter has generally been called one without challenge. A polyphasic approach, comprising 16S rDNA sequencing, profiling restriction fragments of 16S-23S rDNA interspacer regions, lipid analysis, immunological profiling and salt tolerance characterizations, was used to clarify the taxonomy of 76 strains of the genera Caulobacter. Brevundimonas, Hyphomonas and Mycoplana. The described species of the genus Caulobacter formed a paraphyletic group with Caulobacter henricii, Caulobacter fusiformis, Caulobacter vibrioides and Mycoplana segnis (Caulobacter segnis comb. nov.) belonging to Caulobacter sensu stricto. Caulobacter bacteroides (Brevundimonas bacteroides comb. nov.), C. henricii subsp. aurantiacus (Brevundimonas aurantiaca comb. nov.), Caulobacter intermedius (Brevundimonas intermedia comb. nov.), Caulobacter subvibrioides (Brevundimonas subvibrioides comb. nov.), C. subvibrioides subsp. albus (Brevundimonas alba comb. nov.), Caulobacter variabilis (Brevundimonas variabilis comb. nov.) and Mycoplana bullata belong to the genus Brevundimonas. The halophilic species Caulobacter maris and Caulobacter halobacteroides are different from these two genera and form the genus Maricaulis gen. nov. with Maricaulis maris as the type species. Caulobacter leidyia was observed to cluster with species of the genus Sphingomonas. Caulobacter crescentus is synonymous with C. vibrioides and C. halobacteroides is synonymous with Maricaulis maris as determined by these analyses and DNA-DNA hybridization. Biomarkers discerning these different genera were determined. The necessary recombinations have been proposed and a description of Maricaulis is presented.
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Factors controlling in vitro recrystallization of the Caulobacter crescentus paracrystalline S-layer.
Journal of bacteriology, 1997Co-Authors: John F. Nomellini, Seta Küpcü, Uwe B. Sleytr, John SmitAbstract:The S-layer of Caulobacter is a two-dimensional paracrystalline array on the cell surface composed of a single protein, RsaA. We have established conditions for preparation of stable, soluble protein and then efficient in vitro recrystallization of the purified protein. Efficient recrystallization and long range order could not be obtained with pure protein only, though it was apparent that calcium was required for crystallization. Recrystallization was obtained when lipid vesicles were provided, but only when the vesicles contained the specific species of Caulobacter smooth lipopolysaccharide (SLPS) that previous studies implicated as a requirement for attaching the S-layer to the cell surface. The specific type of phospholipids did not appear critical; phospholipids rather different from those present in Caulobacter membranes or archaebacterial tetraether lipids worked equally well. The source of LPS was critical; rough and smooth variants of Salmonella typhimurium LPS as well as the rough form of Caulobacter LPS were ineffective. The requirement for calcium ions for recrystallization was further evaluated; strontium ions could substitute for calcium, and to a lesser extent, cobalt, barium, manganese and magnesium ions also stimulated crystallization. On the other hand, nickel and cadmium provided only weak crystallization stimulation, and zinc, copper, iron, aluminum ions, and the monovalent potassium, sodium, and lithium ions were ineffective. The recrystallization could also be reproduced with Langmuir-Blodgett lipid monolayers at an air-water interface. As with the vesicle experiments, this was only successful when SLPS was incorporated into the lipid mix. The best method for RsaA preparation, leading to apparently monomeric protein that was stable for many months, was an extraction with a low pH aqueous solution. We also achieved recrystallization, albeit at lower efficiency, using RsaA protein solubilized by 8 M urea, a method which allows retrieval of protein from inclusions, when expressed as heterologous protein in Escherichia coli or when retrieved as shed, precipitated protein from certain mutant Caulobacters. In summary, the clarification of recrystallization methods has confirmed the requirement of SLPS as a surface attachment component and suggests that its presence in a membrane-like structure greatly stimulates the extent and quality of S-layer formation. The in vitro approach allowed the demonstration that specific ions are capable of participating in crystallization and now provides an assay for the crystallization potential of modified S-layer proteins, whether they were produced in or can be secreted by Caulobacters.
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Phospho- and sulfolipids as biomarkers of Caulobacter sensu lato, Brevundimonas and Hyphomonas
Systematic and Applied Microbiology, 1997Co-Authors: Wolf-rainer Abraham, Sabine Lindholst, Holger Meyer, Marc Vancanneyt, John SmitAbstract:Summary Phospholipids of type strains and isolates of Caulobacter, Brevundimonas, Hyphomonas and Mycoplana bullata were studied by chromatographic and spectroscopic methods. Using tandem mass spectrometry individual phospholipids were analyzed and their structures elucidated. From the 69 strains included in this study 26 new phosphoglucolipids and two new sulfoquinovosyl-diacylglycerols could be identified. While more than 30 different fatty acids were found in the phospholipid fraction of Caulobacter and Brevundimonas only seven different fatty acids occur within the 26 different phosphoglucolipids identified. The distribution of the different types of phospholipids, especially of the sulfoquinovosyl-, glucoronotaurine amide- and phosphatidyl-glucopyranosyl-diacylglycerols, leads to the identification of four different phenotypic groups of these bacteria in agreement with the phylogeny published by Stahl et al. in 1992. One comprises Caulobacter sensu stricto with the type strain C. vibrioides , the second the type strains of Brevundimonas together with a considerable number of Caulobacter species and the third the halophilic Caulobacter spp . around C. maris . The latter group lacks the phosphatidyl-glucopyranosyl-diacylglycerols but contains sulfoquinovosyl- and glucuronotaurine amide diacylgly- cerols. They can be discerned from Hyphomonas by the occurrence of sulfoquinovosyl-diacylglycerols which are absent in strains of the genus Hyphomonas .
Zemer Gitai - One of the best experts on this subject based on the ideXlab platform.
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Both clinical and environmental Caulobacter species are virulent in the Galleria mellonella infection model.
PloS one, 2020Co-Authors: Gabriel M. Moore, Zemer GitaiAbstract:The Caulobacter genus, including the widely-studied model organism Caulobacter crescentus, has been thought to be non-pathogenic and thus proposed as a bioengineering vector for various environmental remediation and medical purposes. However, Caulobacter species have been implicated as the causative agents of several hospital-acquired infections, raising the question of whether these clinical isolates represent an emerging pathogenic species or whether Caulobacters on whole possess previously-unappreciated virulence capability. Given the proposed environmental and medical applications for C. crescentus, understanding the potential pathogenicity of this bacterium is crucial. Consequently, we sequenced a clinical Caulobacter isolate to determine if it has acquired novel virulence determinants. We found that the clinical isolate represents a new species, Caulobacter mirare that, unlike C. crescentus, grows well in standard clinical culture conditions. C. mirare phylogenetically resembles both C. crescentus and the related C. segnis, which was also thought to be non-pathogenic. The similarity to other Caulobacters and lack of obvious pathogenesis markers suggested that C. mirare is not unique amongst Caulobacters and that consequently other Caulobacters may also have the potential to be virulent. We tested this hypothesis by characterizing the ability of Caulobacters to infect the model animal host Galleria mellonella. In this context, two different lab strains of C. crescentus proved to be as pathogenic as C. mirare, while lab strains of E. coli were non-pathogenic. Further characterization showed that Caulobacter pathogenesis in the Galleria model is mediated by lipopolysaccharide (LPS), and that differences in LPS chemical composition across species could explain their differential toxicity. Taken together, our findings suggest that many Caulobacter species can be virulent in specific contexts and highlight the importance of broadening our methods for identifying and characterizing potential pathogens.
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Both clinical and environmental Caulobacter species act as opportunistic pathogens
2019Co-Authors: Gabriel M. Moore, Zemer GitaiAbstract:ABSTRACT The Caulobacter genus, including the widely-studied model organism Caulobacter crescentus, has been thought to be non-pathogenic and thus proposed as a bioengineering vector for various environmental remediation and medical purposes. However, Caulobacter species have been implicated as the causative agents of several hospital-acquired infections, raising the question of whether these clinical isolates represent an emerging pathogenic species or whether Caulobacters on whole possess previously-unappreciated virulence capability. Given the proposed environmental and medical applications for C. crescentus, understanding the potential pathogenicity and human health implications of this bacterium is crucial. Consequently, we sequenced a clinical Caulobacter isolate to determine if it has acquired novel virulence determinants. We found that the clinical isolate represents a new species, Caulobacter mirare. C. mirare phylogenetically resembles both C. crescentus and the related C. segnis, which was also thought to be non-pathogenic. The similarity to other Caulobacters and lack of obvious pathogenesis markers suggested that C. mirare is not unique amongst Caulobacters and that consequently other Caulobacters may also have the potential to be virulent. We tested this hypothesis by characterizing the ability of Caulobacters to infect the model animal host Galleria mellonella. In this context, two different lab strains of C. crescentus proved to be as pathogenic as C. mirare, while lab strains of E. coli were non-pathogenic. Further characterization showed that Caulobacter pathogenesis is mediated by a dose-dependent, cell-associated toxic factor that does not require active bacterial cells or host cellular innate immunity to elicit its toxic effects. Finally, we show that C. crescentus does not grow well in standard clinical culture conditions, suggesting that Caulobacter infections may be more common than generally appreciated but rarely cultured. Taken together, our findings redefine Caulobacters as opportunistic pathogens and highlight the importance of broadening our methods for identifying and characterizing pathogens. AUTHOR SUMMARY Bacterial species have historically been classified as either capable of causing disease in an animal (pathogenic) or not. Caulobacter species represent a class of bacteria that were thought to be non-pathogenic. Caulobacters have been widely studied and proposed to be used for various industrial and medical applications due to their presumed safety. However, recent reports of human Caulobacter infections raised the question of whether disease-causing Caulobacters have acquired special factors that help them cause disease or whether the ability to infect is a more general feature of most Caulobacters. By combining genomic sequencing and animal infection studies we show that a clinical Caulobacter strain is similar to lab Caulobacters and that all Caulobacters studied can infect a model host. We explore the mechanism of this infectivity and show that it is due to a toxic factor that associates with Caulobacter cells. We also provide a possible explanation for why Caulobacters have not traditionally been isolated from human patients, owing to their inability to tolerate the salt levels used in most medical culturing systems.
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Diverse Functions for Six Glycosyltransferases in Caulobacter crescentus Cell Wall Assembly
Journal of bacteriology, 2013Co-Authors: Anastasiya A. Yakhnina, Zemer GitaiAbstract:The essential process of peptidoglycan synthesis requires two enzymatic activities, transpeptidation and transglycosylation. While the PBP2 and PBP3 transpeptidases perform highly specialized functions that are widely conserved, the specific roles of different glycosyltransferases are poorly understood. For example, Caulobacter crescentus encodes six glycosyltransferase paralogs of largely unknown function. Using genetic analyses, we found that Caulobacter glycosyltransferases are primarily redundant but that PbpX is responsible for most of the essential glycosyltransferase activity. Cells containing PbpX as their sole glycosyltransferase are viable, and the loss of pbpX leads to a general defect in the integrity of the cell wall structure even in the presence of the other five glycosyltransferases. However, neither PbpX nor any of its paralogs is required for the specific processes of cell elongation or division, while the cell wall synthesis required for stalk biogenesis is only partially disrupted in several of the glycosyltransferase mutants. Despite their genetic redundancy, Caulobacter glycosyltransferases exhibit different subcellular localizations. We suggest that these enzymes have specialized roles and normally function in distinct subcomplexes but retain the ability to substitute for one another so as to ensure the robustness of the peptidoglycan synthesis process.
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Physiological role of stalk lengthening in Caulobacter crescentus
Communicative & integrative biology, 2013Co-Authors: Eric A. Klein, Yves V Brun, Susan Schlimpert, Velocity Hughes, Martin Thanbichler, Zemer GitaiAbstract:The Gram-negative bacterium Caulobacter crescentus forms a thin polar stalk, which mediates its attachment to solid surfaces. Whereas stalks remain short (1 µm) in nutrient-rich conditions, they lengthen dramatically (up to 30 µm) upon phosphate starvation. A long-standing hypothesis is that the Caulobacter stalk functions as a nutrient scavenging "antenna" that facilitates phosphate uptake and transport to the cell body. The mechanistic details of this model must be revisited, given our recent identification of a protein-mediated diffusion barrier, which prevents the exchange of both membrane and soluble proteins between the stalk extension and the cell body. In this report, we discuss the potential of stalks to facilitate nutrient uptake and propose additional physiological roles for stalk elongation in Caulobacter cells.
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Growth Conditions Regulate the Requirements for Caulobacter Chromosome Segregation
Journal of bacteriology, 2008Co-Authors: Conrad W. Shebelut, Rasmus B. Jensen, Zemer GitaiAbstract:Growth environments are important metabolic and developmental regulators. Here we demonstrate a growth environment-dependent effect on Caulobacter chromosome segregation of a small-molecule inhibitor of the MreB bacterial actin cytoskeleton. Our results also implicate ParAB as important segregation determinants, suggesting that multiple distinct mechanisms can mediate Caulobacter chromosome segregation and that their relative contributions can be environmentally regulated.
Long Jin - One of the best experts on this subject based on the ideXlab platform.
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Caulobacter soli sp. nov., isolated from soil sampled at Jiri Mountain, Republic of Korea.
International journal of systematic and evolutionary microbiology, 2020Co-Authors: Yuanyuan Yang, Chun-zhi Jin, Feng-jie Jin, Jong Min Lee, Chang-jin Kim, Hyung-gwan Lee, Long JinAbstract:A Gram-stain-negative, yellow-pigmented, aerobic, non-spore-forming, motile with a single polar flagellum and rod-shaped bacterium, Ji-3-8T, was isolated from a soil sample taken from Jiri Mountain, Republic of Korea. Comparative 16S rRNA gene sequence studies showed the isolate had clear affiliation with Alphaproteobacteria and the closest relatedness to Caulobacter rhizosphaerae KCTC 52515T, Caulobacter henricii ATCC 15253T, Caulobacter segnis ATCC 21756T, Caulobacter hibisci THG-AG3.4T, Caulobacter flavus RHGG3T and Caulobacter vibrioides CB51T showing 99.1, 98.9, 97.7, 97.6, 97.5 and 97.4 % 16S rRNA gene sequence similarity, respectively, and 94.7–96.5 % to the remaining species of genus Caulobacter . The predominant ubiquinone was Q-10 and the major fatty acids were C18 : 1 ω7c 11-methyl, C16 : 0, summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c) and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c). The major polar lipids were found to be phosphatidylglycerol, two unidentified phosphoglycolipid and two unidentified glycolipids. The G+C content of the genomic DNA of strain Ji-3-8T was 68.1 mol%. Average nucleotide identity and digital DNA–DNA hybridization values of strain Ji-3-8T with C. rhizosphaerae KCTC 52515T, C. henricii ATCC 15253T, C. segnis ATCC 21756T, C. flavus RHGG3T and C. vibrioides were 79.7–87.7% and 23.0–34.3%, respectively. Based on the polyphasic evidence, it is proposed that strain Ji-3-8T forms a novel species in the genus Caulobacter , for which the name Caulobacter soli sp. nov. is proposed. The type strain is Ji-3-8T (=CCTCC AB 2019389T=KCTC 72990T).
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Caulobacter profunda sp. nov., isolated from deep freshwater sediment.
International journal of systematic and evolutionary microbiology, 2013Co-Authors: Long Jin, Hyung-gwan Lee, Jay Jung Lee, Sanghyup Lee, Chi-yong AhnAbstract:The Gram-stain-negative, aerobic, non-spore-forming, motile, with a single polar flagellum, or non-motile (stalked) and rod-shaped bacteria, DS48-5-2(T) and DS48-6-3, were isolated from a sediment sample collected from a depth of 48 m taken from Daechung Reservoir, Republic of Korea. Comparative 16S rRNA gene sequence studies showed that the two isolates had clear affiliation with Alphaproteobacteria and the closest relatedness to Caulobacter mirabilis FWC 38(T), Caulobacter fusiformis ATCC 15257(T) and Caulobacter daechungensis H-E3-2(T) showing 98.5%, 97.3% and 97.3% 16S rRNA gene sequence similarity, respectively, and 96.1-96.7% similarity to all other species of the genus Caulobacter. The two isolates shared 100 % 16S rRNA gene sequence similarity. The predominant ubiquinone was Q-10. The major fatty acids were summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c), C16:0, C18:0ω7c 11-methyl and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The G+C contents of the genomic DNA of strains DS48-5-2(T) and DS48-6-3 were 66.7 mol% and 66.2 mol%, respectively. DNA-DNA hybridization values of strains DS48-5-2(T) and DS48-6-3 with C. mirabilis FWC 38(T), C. fusiformis ATCC 15257(T) and C. daechungensis H-E3-2(T) were 19.3 %-24.4 %. Thus, based on the evidence from polyphasic studies, it is proposed that strains DS48-5-2(T) and DS48-6-3 are representatives of a novel species in the genus Caulobacter, for which the name Caulobacter profunda sp. nov. is proposed. The type strain is DS48-5-2(T) ( = KCTC 32480(T) = JCM 19440(T)).
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Caulobacter daechungensis sp. nov., a stalked bacterium isolated from a eutrophic reservoir.
International journal of systematic and evolutionary microbiology, 2012Co-Authors: Long Jin, Hyung-gwan Lee, Hee-sik Kim, Chi-yong AhnAbstract:A Gram-stain-negative, aerobic, non-spore-forming, curved, rod-shaped bacterium, H-E3-2(T), was isolated from a water sample taken from Daechung Reservoir, Republic of Korea, during the late-blooming period of cyanobacteria. Strain H-E3-2(T) was motile with a single polar flagellum or non-motile (stalked cell). Comparative 16S rRNA gene sequence studies showed the isolate had a clear affiliation with the class Alphaproteobacteria and was most closely related to Caulobacter fusiformis ATCC 15257(T) and Caulobacter mirabilis LMG 24261(T), showing 97.6 and 97.3 % 16S rRNA gene sequence similarity, respectively, and 95.3-96.3 % similarity to all other species of the genus Caulobacter. The predominant ubiquinone was Q-10. The major fatty acids were summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and C16 : 0. The G+C content of the genomic DNA of strain H-E3-2(T) was 64.7 mol%. DNA-DNA hybridization values of strain H-E3-2(T) with C. fusiformis ATCC 15257(T) and C. mirabilis LMG 24261(T) were 21.2 and 19.7 %, respectively. Thus, based on the results of polyphasic analysis, it is proposed that strain H-E3-2(T) represents a novel species of the genus Caulobacter, for which the name Caulobacter daechungensis sp. nov. is proposed. The type strain is H-E3-2(T) ( = KCTC 32211(T) = JCM 18689(T)).
En-dong Yang - One of the best experts on this subject based on the ideXlab platform.
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Caulobacter rhizosphaerae sp. nov., a stalked bacterium isolated from rhizosphere soil
International Journal of Systematic and Evolutionary Microbiology, 2017Co-Authors: En-dong Yang, Zhuo-xin Yuan, Weiyun WangAbstract:The Gram-reaction-negative, aerobic, white- to pale-yellow-coloured and rod-shaped bacterium with a single polar flagellum or a stalk, designated strain 7F14T, was isolated from rhizosphere soil of cultivated watermelon (Citrullus lanatus) collected from Hefei, China. Growth of strain 7F14T was observed at pH 6.0–9.0, 10–30 °C and in the presence of 0–1 % (w/v) NaCl. Cells were catalase-negative and oxidase-positive. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain 7F14T formed a phyletic lineage within the genus Caulobacter of the family Caulobacteraceae and showed the highest 16S rRNA gene sequence similarities to Caulobacter henricii ATCC 15253T (98.66 %), Caulobacter segnis ATCC 21756T (98.27 %), Caulobacter vibrioides CB51T (97.92 %) and C aulobacter flavus RHGG3T (97.44 %). The G+C content of the genomic DNA was 68.6 mol%. Strain 7F14T contained Q-10 as the sole ubiquinone and 11-methyl C18 : 1ω7c, C18 : 1ω7c, C16 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as the major fatty acids. The polar lipids profile consisted of phosphatidylglycerol, an unknown phosphoglycolipid, five unknown glycolipids, an unknown phospholipid and three unknown lipids. DNA–DNA relatedness values to the most closely related type strains Caulobacter henricii DSM 4730T and Caulobacter segnis DSM 7131T were 26.0 and 19.7 %, respectively. Based on unique phenotypic traits, and phylogenetic, chemotaxonomic and DNA–DNA hybridization results, strain 7F14T should be classified as a representative of a novel species of the genus Caulobacter , for which the name C aulobacter rhizosphaerae sp. nov. is proposed. The type strain is 7F14T (=CGMCC 1.15915T=KCTC 52515T).
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Caulobacter flavus sp. nov., a stalked bacterium isolated from rhizosphere soil.
International Journal of Systematic and Evolutionary Microbiology, 2015Co-Authors: En-dong Yang, Xinyun TangAbstract:A Gram-stain-negative, aerobic, yellow-pigmented and rod-shaped bacterium with a single polar flagellum or a stalk, designated strain RHGG3T, was isolated from rhizosphere soil of cultivated watermelon (Citrullus lanatus) collected from Hefei, China. Optimal growth of strain RHGG3T was observed at pH 7.0 and 28–30 °C. Cells were catalase-positive and oxidase-negative. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain RHGG3T belonged to the genus Caulobacter and showed the highest 16S rRNA gene sequence similarities to Caulobacter segnis ATCC 21756T (98.6 %), Caulobacter vibrioides CB51T (98.3 %) and Caulobacter henricii ATCC 15253T (97.2 %). The G+C content of the genomic DNA was 70 mol%. Strain RHGG3T contained Q-10 as the sole ubiquinone and the major fatty acids (>8 %) were 11-methyl C18 : 1ω7c, C18 : 1ω7c, C16 : 0, C15 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The polar lipids were various unknown glycolipids, phosphatidylglycerol and phosphoglycolipids. DNA–DNA relatedness of strain RHGG3T to type strains of the most closely related species (Caulobacter segnis ATCC 21756T, Caulobacter vibrioides DSM 4738 and Caulobacter henricii ATCC 15253T) was 32.4–40.9 %. Based on polyphasic taxonomy analysis (phylogenetic, unique phenotypic traits, chemotaxonomic and DNA–DNA hybridizations), strain RHGG3T represents a novel species of the genus Caulobacter, for which the name Caulobacter flavus sp. nov. is proposed. The type strain is RHGG3T ( = CGMCC 1.15093T = KCTC 42581T = JCM 30763T).