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Current Opinion in Microbiology Apr 2021In the past decades, Caulobacter crescentus has been extensively studied, mostly regarding its dimorphic, asymmetric life cycle. Its distinct mode of reproduction and... (Review)
Review
In the past decades, Caulobacter crescentus has been extensively studied, mostly regarding its dimorphic, asymmetric life cycle. Its distinct mode of reproduction and the need to optimally adapt to ever-changing environmental conditions require tight coordination of gene regulation. Post-transcriptional regulation through non-coding RNAs and RNA-binding proteins constitutes an important layer of expression control in bacteria, but its principles and mechanisms in Caulobacter have only recently been explored. RNA-binding proteins including the RNA chaperone Hfq and ribonuclease RNase E contribute to the activity of regulatory RNAs. Riboswitches and RNA thermometers govern expression of downstream open reading frames, while the small regulatory RNAs CrfA, ChvR and GsrN instead control targets encoded in trans by direct base-pairing interactions.
Topics: Bacterial Proteins; Base Pairing; Caulobacter crescentus; Gene Expression Regulation, Bacterial; RNA, Bacterial; RNA, Messenger; RNA, Small Untranslated
PubMed: 33529919
DOI: 10.1016/j.mib.2021.01.002 -
Biochimica Et Biophysica Acta. Gene... Jul 2019Caulobacter crescentus is a free-living Alphaproteobacterium that thrives in oligotrophic environments. This review focuses on the regulatory network used by this... (Review)
Review
Caulobacter crescentus is a free-living Alphaproteobacterium that thrives in oligotrophic environments. This review focuses on the regulatory network used by this bacterium to control the levels of cell division proteins, their organization inside the cell and their activity as a function of the cell cycle. Strikingly, C. crescentus makes frequent use of master transcriptional regulators and epigenetic signals, most likely to synchronize cell division with other events of the cell cycle. In addition, cellular metabolism and DNA damage sensors emerge as central players regulating cell division in response to changing environmental conditions.
Topics: Bacterial Proteins; Caulobacter crescentus; Cell Division; DNA Damage; Gene Expression Regulation, Bacterial; Gene Regulatory Networks; Stress, Physiological
PubMed: 29715525
DOI: 10.1016/j.bbagrm.2018.04.005 -
Current Biology : CB Jul 2012
Topics: Caulobacter crescentus; Flagella; Gene Expression Regulation, Bacterial
PubMed: 22789993
DOI: 10.1016/j.cub.2012.05.036 -
FEMS Microbiology Reviews Jan 2012Caulobacter crescentus uses a multi-layered system of oscillating regulators to program different developmental fates into each daughter cell at division. This is... (Review)
Review
Caulobacter crescentus uses a multi-layered system of oscillating regulators to program different developmental fates into each daughter cell at division. This is achieved by superimposing gene expression, subcellular localization, phosphorylation, and regulated proteolysis to form a complex regulatory network that integrates chromosome replication, segregation, polar differentiation, and cytokinesis. In this review, we outline the current state of research in the field of Caulobacter development, emphasizing new findings that elaborate how the developmental program is modulated by factors such as the environment or the metabolic state of the cell.
Topics: Caulobacter crescentus; Cell Division; Gene Expression Regulation; Signal Transduction
PubMed: 22091823
DOI: 10.1111/j.1574-6976.2011.00309.x -
Virulence Jan 2018Non-fermenting Gram-negative bacteria are problematic in clinical locations, being one of the most prevalent causes of nosocomial infections. Many of these... (Review)
Review
Non-fermenting Gram-negative bacteria are problematic in clinical locations, being one of the most prevalent causes of nosocomial infections. Many of these non-fermenting Gram-negative bacteria are opportunistic pathogens that affect patients that are suffering with underlying medical conditions and diseases. Brevundimonas spp., in particular Brevundimonas diminuta and Brevundimonas vesicularis, are a genus of non-fermenting Gram-negative bacteria considered of minor clinical importance. Forty-nine separate instances of infection relating to Brevundimonas spp were found in the scientific literature along with two pseudo-infections. The majority of these instances were infection with Brevundimonas vesicularis (thirty-five cases - 71%). The major condition associated with Brevundimonas spp infection was bacteraemia with seventeen individual cases/outbreaks (35%). This review identified forty-nine examples of Brevundimonas spp. infections have been discussed in the literature. These findings indicate that infection review programs should consider investigation of possible Brevundimonas spp outbreaks if these bacteria are clinically isolated in more than one patient.
Topics: Bacteremia; Caulobacteraceae; Communicable Diseases, Emerging; Disease Outbreaks; Global Health; Gram-Negative Bacterial Infections; Humans; Opportunistic Infections
PubMed: 29484917
DOI: 10.1080/21505594.2017.1419116 -
ELife Dec 2016Although free-living and obligate intracellular bacteria are both polarized it is unclear whether the underlying polarization mechanisms and effector proteins are...
Although free-living and obligate intracellular bacteria are both polarized it is unclear whether the underlying polarization mechanisms and effector proteins are conserved. Here we dissect at the cytological, functional and structural level a conserved polarization module from the free living α-proteobacterium and an orthologous system from an obligate intracellular (rickettsial) pathogen. The NMR solution structure of the zinc-finger (ZnR) domain from the bifunctional and bipolar ZitP pilus assembly/motility regulator revealed conserved interaction determinants for PopZ, a bipolar matrix protein that anchors the ParB centromere-binding protein and other regulatory factors at the poles. We show that ZitP regulates cytokinesis and the localization of ParB and PopZ, targeting PopZ independently of the previously known binding sites for its client proteins. Through heterologous localization assays with rickettsial ZitP and PopZ orthologs, we document the shared ancestries, activities and structural determinants of a (bi-)polarization system encoded in free-living and obligate intracellular α-proteobacteria.
Topics: ATP-Binding Cassette Transporters; Bacterial Proteins; Cation Transport Proteins; Caulobacter crescentus; Cell Polarity; Cytokinesis; Protein Binding; Protein Multimerization; Protein Transport; Rickettsia
PubMed: 28008852
DOI: 10.7554/eLife.20640 -
Current Opinion in Microbiology Dec 2013In rod shaped bacteria, numerous cellular components are targeted to the cell poles, and such localization is often important for optimal function. In particular,... (Review)
Review
In rod shaped bacteria, numerous cellular components are targeted to the cell poles, and such localization is often important for optimal function. In particular, recognition of poles is often linked to division site selection, chromosome segregation, chemotactic signaling, and motility. Recent advances in understanding polarity include identification of a Vibrio cholerae protein that mediates polar localization of a chromosome origin and chemotaxis clusters, as well as a downstream protein that contributes solely to localization of chemotaxis proteins. In Caulobacter crescentus, the molecular mechanisms by which polar determinants and effectors are localized, and the key roles for nucleotide-dependent switches, have been defined. Finally, roles for, and interactions between, factors that mediate environmentally determined polarity in Myxococcus xanthus have recently been characterized.
Topics: Caulobacter crescentus; Cell Polarity; Myxococcus xanthus; Vibrio cholerae
PubMed: 24029491
DOI: 10.1016/j.mib.2013.08.006 -
Annual Review of Genetics Nov 2016Protein degradation is essential for all living things. Bacteria use energy-dependent proteases to control protein destruction in a highly specific manner. Recognition... (Review)
Review
Protein degradation is essential for all living things. Bacteria use energy-dependent proteases to control protein destruction in a highly specific manner. Recognition of substrates is determined by the inherent specificity of the proteases and through adaptor proteins that alter the spectrum of substrates. In the α-proteobacterium Caulobacter crescentus, regulated protein degradation is required for stress responses, developmental transitions, and cell cycle progression. In this review, we describe recent progress in our understanding of the regulated and stress-responsive protein degradation pathways in Caulobacter. We discuss how organization of highly specific adaptors into functional hierarchies drives destruction of proteins during the bacterial cell cycle. Because all cells must balance the need for degradation of many true substrates with the toxic consequences of nonspecific protein destruction, principles found in one system likely generalize to others.
Topics: Bacterial Proteins; Caulobacter; Cell Cycle; Peptide Hydrolases; Proteolysis; Stress, Physiological
PubMed: 27893963
DOI: 10.1146/annurev-genet-120215-035235 -
International Journal of Molecular... May 2022Arsenic (As), distributed widely in the natural environment, is a toxic substance which can severely impair the normal functions in living cells. Research on the genetic...
Arsenic (As), distributed widely in the natural environment, is a toxic substance which can severely impair the normal functions in living cells. Research on the genetic determinants conferring functions in arsenic resistance and metabolism is of great importance for remediating arsenic-contaminated environments. Many organisms, including bacteria, have developed various strategies to tolerate arsenic, by either detoxifying this harmful element or utilizing it for energy generation. More and more new arsenic resistance () determinants have been identified to be conferring resistance to diverse arsenic compounds and encoded in operons. There is a hazard in mobilizing arsenic during gold-mining activities due to gold- and arsenic-bearing minerals coexisting. In this study, we isolated 8 gold enrichment strains from the Zijin gold and copper mine (Longyan, Fujian Province, China) wastewater treatment site soil, at an altitude of 192 m. We identified two strains, Au-Bre29 and Au-Bre30, among these eight strains, having a high minimum inhibitory concentration (MIC) for As(III). These two strains contained the same operons but displayed differences regarding secretion of extra-polymeric substances (EPS) upon arsenite (As(III)) stress. Au-Bre29 contained one extra plasmid but without harboring any additional genes compared to Au-Bre30. We optimized the growth conditions for strains Au-Bre29 and Au-Bre30. Au-Bre30 was able to tolerate both a lower pH and slightly higher concentrations of NaCl. We also identified , a folate synthesis gene, in the operon of these two strains. In most organisms, folate synthesis begins with a FolE (GTP-Cyclohydrolase I)-type enzyme, and the corresponding gene is typically designated (in bacteria) or (in mammals). Heterologous expression of , cloned from Au-Bre30, in the arsenic-hypersensitive strain AW3110, conferred resistance to As(III), arsenate (As(V)), trivalent roxarsone (Rox(III)), pentavalent roxarsone (Rox(V)), trivalent antimonite (Sb(III)), and pentavalent antimonate (Sb(V)), indicating that folate biosynthesis is a target of arsenite toxicity and increased production of folate confers increased resistance to oxyanions. Genes encoding Acr3 and ArsH were shown to confer resistance to As(III), Rox(III), Sb(III), and Sb(V), and ArsH also conferred resistance to As(V). Acr3 did not confer resistance to As(V) and Rox(V), while ArsH did not confer resistance to Rox(V).
Topics: Arsenic; Arsenites; Bacteria; Bacterial Proteins; Caulobacteraceae; Escherichia coli; Folic Acid; Gold; Roxarsone
PubMed: 35628430
DOI: 10.3390/ijms23105619 -
Biochemical Society Transactions Feb 2019The environmental is a classical model to study the regulation of the bacterial cell cycle. It divides asymmetrically, giving a stalked cell that immediately enters S... (Review)
Review
The environmental is a classical model to study the regulation of the bacterial cell cycle. It divides asymmetrically, giving a stalked cell that immediately enters S phase and a swarmer cell that stays in the G1 phase until it differentiates into a stalked cell. Its genome consists in a single circular chromosome whose replication is tightly regulated so that it happens only in stalked cells and only once cell cycle. Imbalances in chromosomal copy numbers are the most often highly deleterious, if not lethal. This review highlights recent discoveries on pathways that control chromosome replication when is exposed to optimal or less optimal growth conditions. Most of these pathways target two proteins that bind directly onto the chromosomal origin: the highly conserved DnaA initiator of DNA replication and the CtrA response regulator that is found in most The concerted inactivation and proteolysis of CtrA during the swarmer-to-stalked cell transition license cells to enter S phase, while a replisome-associated Regulated Inactivation and proteolysis of DnaA (RIDA) process ensures that initiation starts only once cell cycle. When is stressed, it turns on control systems that delay the G1-to-S phase transition or the elongation of DNA replication, most probably increasing its fitness and adaptation capacities.
Topics: Caulobacter crescentus; Chromosomes, Bacterial; DNA Replication; Gene Expression Regulation, Bacterial; Gram-Negative Bacteria
PubMed: 30626709
DOI: 10.1042/BST20180460