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Romain Grangeon, John Zupan, Yeonji Jeon, Patricia C Zambryski
Agrobacterium tumefaciens grows by addition of peptidoglycan (PG) at one pole of the bacterium. During the cell cycle, the cell needs to maintain two different developmental programs, one at the growth pole and another at the inert old pole. Proteins involved in this process are not yet well characterized. To further characterize the role of pole-organizing protein A. tumefaciens PopZ (PopZ At ), we created deletions of the five PopZ At domains and assayed their localization. In addition, we created a popZAt deletion strain (ΔpopZAt ) that exhibited growth and cell division defects with ectopic growth poles and minicells, but the strain is unstable...
November 14, 2017: MBio
Xing-Jian Xu, Guo-Li Lai, Chang-Qiao Chi, Jie-Yu Zhao, Ying-Chun Yan, Yong Nie, Xiao-Lei Wu
In this study, the removal of nutrients and chlorpyrifos as well as shifts of planktonic bacterial communities in constructed microcosms were investigated to evaluate the influence of Phragmites australis, Nymphaea alba, and Myriophyllum verticillatum, and their combination, on the restoration of eutrophic water containing chlorpyrifos. Plant-treated groups showed a higher pollutant removal rate than did no-remediation controls, indicating that treatment with plants is effective at remediation of eutrophic water containing chlorpyrifos...
October 31, 2017: Chemosphere
Patrick J Lariviere, Piotr Szwedziak, Christopher R Mahone, Jan Löwe, Erin D Goley
During bacterial division, polymers of the tubulin-like GTPase FtsZ assemble at midcell to form the cytokinetic Z-ring, which coordinates peptidoglycan (PG) remodeling and envelope constriction. Curvature of FtsZ filaments promotes membrane deformation in vitro, but its role in division in vivo remains undefined. Inside cells, FtsZ directs PG insertion at the division plane, though it is unclear how FtsZ structure and dynamics are mechanistically coupled to PG metabolism. Here we study FzlA, a division protein that stabilizes highly curved FtsZ filaments, as a tool for assessing the contribution of FtsZ filament curvature to constriction...
November 9, 2017: Molecular Microbiology
Chau D Vo, Hanna L Shebert, Shannon Zikovich, Rebecca A Dryer, Tony P Huang, Lindsey J Moran, Juno Cho, Douglas R Wassarman, Bryn E Falahee, Peter D Young, Garrick H Gu, James F Heinl, John W Hammond, Taylor N Jackvony, Thomas E Frederick, Jimmy A Blair
To address the growing need for new antimicrobial agents, we explored whether inhibition of bacterial signaling machinery could inhibit bacterial growth. Because bacteria rely on two-component signaling systems to respond to environmental changes, and because these systems are both highly conserved and mediated by histidine kinases, inhibiting histidine kinases may provide broad spectrum antimicrobial activity. The histidine kinase ATP binding domain is conserved with the ATPase domain of eukaryotic Hsp90 molecular chaperones...
October 19, 2017: Bioorganic & Medicinal Chemistry Letters
Jutta Nesper, Isabelle Hug, Setsu Kato, Chee-Seng Hee, Judith Maria Habazettl, Pablo Manfredi, Stephan Grzesiek, Tilman Schirmer, Thierry Emonet, Urs Jenal
The flagellar motor is a sophisticated rotary machine facilitating locomotion and signal transduction. Owing to its important role in bacterial behavior, its assembly and activity are tightly regulated. For example, chemotaxis relies on a sensory pathway coupling chemical information to rotational bias of the motor through phosphorylation of the motor switch protein CheY. Using a chemical proteomics approach, we identified a novel family of CheY-like (Cle) proteins in Caulobacter crescentus, which tune flagellar activity in response to binding of the second messenger c-di-GMP to a C-terminal extension...
November 1, 2017: ELife
Kousik Sundararajan, Erin D Goley
The bacterial tubulin FtsZ2 polymerizes to form a discontinuous ring that drives bacterial cell division by directing local cell wall synthesis. FtsZ comprises a polymerizing GTPase domain, an intrinsically disordered C-terminal linker (CTL) and a C-terminal conserved peptide (CTC). FtsZ protofilaments align circumferentially in the cell, with the CTC mediating attachment to membrane-associated division proteins. The assembly of FtsZ protofilaments into dynamic clusters is critical for cell division, but the interactions between protofilaments and regulatory mechanisms that mediate cluster assembly and dynamics are unknown...
October 31, 2017: Journal of Biological Chemistry
Courtney K Ellison, Jingbo Kan, Rebecca S Dillard, David T Kysela, Adrien Ducret, Cecile Berne, Cheri M Hampton, Zunlong Ke, Elizabeth R Wright, Nicolas Biais, Ankur B Dalia, Yves V Brun
It is critical for bacteria to recognize surface contact and initiate physiological changes required for surface-associated lifestyles. Ubiquitous microbial appendages called pili are involved in sensing surfaces and facilitating downstream behaviors, but the mechanism by which pili mediate surface sensing has been unclear. We visualized Caulobacter crescentus pili undergoing dynamic cycles of extension and retraction. Within seconds of surface contact, these cycles ceased, which coincided with synthesis of the adhesive holdfast required for attachment...
October 27, 2017: Science
Isabelle Hug, Siddharth Deshpande, Kathrin S Sprecher, Thomas Pfohl, Urs Jenal
When bacteria encounter surfaces, they respond with surface colonization and virulence induction. The mechanisms of bacterial mechanosensation and downstream signaling remain poorly understood. Here, we describe a tactile sensing cascade in Caulobacter crescentus in which the flagellar motor acts as sensor. Surface-induced motor interference stimulated the production of the second messenger cyclic diguanylate by the motor-associated diguanylate cyclase DgcB. This led to the allosteric activation of the glycosyltransferase HfsJ to promote rapid synthesis of a polysaccharide adhesin and surface anchoring...
October 27, 2017: Science
Laura Salusjärvi, Mervi Toivari, Maija-Leena Vehkomäki, Outi Koivistoinen, Dominik Mojzita, Klaus Niemelä, Merja Penttilä, Laura Ruohonen
The important platform chemicals ethylene glycol and glycolic acid were produced via the oxidative D-xylose pathway in the yeast Saccharomyces cerevisiae. The expression of genes encoding D-xylose dehydrogenase (XylB) and D-xylonate dehydratase (XylD) from Caulobacter crescentus and YagE or YjhH aldolase and aldehyde dehydrogenase AldA from Escherichia coli enabled glycolic acid production from D-xylose up to 150 mg/L. In strains expressing only xylB and xylD, 29 mg/L 2-keto-3-deoxyxylonic acid [(S)-4,5-dihydroxy-2-oxopentanoic acid] (2K3DXA) was produced and D-xylonic acid accumulated to ca...
October 16, 2017: Applied Microbiology and Biotechnology
Ingrid R Alves, Marco A Lima-Noronha, Larissa G Silva, Frank S Fernández-Silva, Aline Luiza D Freitas, Marilis V Marques, Rodrigo S Galhardo
imuABC (imuAB dnaE2) genes are responsible for SOS-mutagenesis in Caulobacter crescentus and other bacterial species devoid of umuDC. In this work, we have constructed operator-constitutive mutants of the imuABC operon. We used this genetic tool to investigate the effect of SOS-induced levels of these genes upon both spontaneous and damage-induced mutagenesis. We showed that constitutive expression of imuABC does not increase spontaneous or damage-induced mutagenesis, nor increases cellular resistance to DNA-damaging agents...
September 14, 2017: DNA Repair
James A Taylor, Gaël Panis, Patrick H Viollier, Gregory T Marczynski
We searched for regulators of chromosome replication in the cell cycle model Caulobacter crescentus and found a novel DNA-binding protein (GapR) that selectively aids the initiation of chromosome replication and the initial steps of chromosome partitioning. The protein binds the chromosome origin of replication (Cori) and has higher-affinity binding to mutated Cori-DNA that increases Cori-plasmid replication in vivo. gapR gene expression is essential for normal rapid growth and sufficient GapR levels are required for the correct timing of chromosome replication...
September 6, 2017: Nucleic Acids Research
Patrick D Curtis
The Caulobacter crescentus cell extension known as a stalk represents an unusual bacterial morphology. C. crescentus produces stalks under multiple nutrient conditions, but the length of the stalk is increased in response to phosphate starvation. However, the exact function of the stalk is not known, nor is it known how much stalk biogenesis or function is conserved with other stalked bacteria. Work presented here shows that many organisms in the Caulobacter genus and the next closest genus (Brevundimonas) generally do not synthesize stalks in the relatively-rich PYE growth medium, suggesting that the synthesis of a stalk under nutrient-rich conditions by C...
2017: PloS One
Elizabeth L Meier, Allison K Daitch, Qing Yao, Anant Bhargava, Grant J Jensen, Erin D Goley
During its life cycle, Caulobacter crescentus undergoes a series of coordinated shape changes, including generation of a polar stalk and reshaping of the cell envelope to produce new daughter cells through the process of cytokinesis. The mechanisms by which these morphogenetic processes are coordinated in time and space remain largely unknown. Here we demonstrate that the conserved division complex FtsEX controls both the early and late stages of cytokinesis in C. crescentus, namely initiation of constriction and final cell separation...
September 2017: PLoS Genetics
Gabriela Moya, Zheng-Fei Yan, KyungHwa Won, Jung-Eun Yang, Qi-Jun Wang, MooChang Kook, Tae-Hoo Yi
A Gram-stain-negative, smooth, bright yellow-pigmented, aerobic, catalase- and oxidase-positive and rod-shaped bacterial strain was isolated from rhizosphere of Hibiscus syriacus L. (Mugunghwa flower) located in Kyung Hee University, Yongin, Gyeonggi, South Korea. Cells were dimorphic, non-motile or non-stalked, and motile by means of peritrichous flagellum. The strain, named THG-AG3.4T, grew at 15-35 °C, at pH 6.5-9.0 and in the presence of 0-1.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain THG-AG3...
September 2017: International Journal of Systematic and Evolutionary Microbiology
Ngat T Tran, Michael T Laub, Tung B K Le
The structural maintenance of chromosomes (SMC) complex plays an important role in chromosome organization and segregation in most living organisms. In Caulobacter crescentus, SMC is required to align the left and the right arms of the chromosome that run in parallel down the long axis of the cell. However, the mechanism of SMC-mediated alignment of chromosomal arms remains elusive. Here, using genome-wide methods and microscopy of single cells, we show that Caulobacter SMC is recruited to the centromeric parS site and that SMC-mediated arm alignment depends on the chromosome-partitioning protein ParB...
August 29, 2017: Cell Reports
Aleksandra Zielińska, Maria Billini, Andrea Möll, Katharina Kremer, Ariane Briegel, Adrian Izquierdo Martinez, Grant J Jensen, Martin Thanbichler
Most bacteria possess a peptidoglycan cell wall that determines their morphology and provides mechanical robustness during osmotic challenges. The biosynthesis of this structure is achieved by a large set of synthetic and lytic enzymes with varying substrate specificities. Although the biochemical functions of these proteins are conserved and well-investigated, the precise roles of individual factors and the regulatory mechanisms coordinating their activities in time and space remain incompletely understood...
November 2017: Molecular Microbiology
Irnov Irnov, Zhe Wang, Nicholas D Jannetty, Julian A Bustamante, Kyu Y Rhee, Christine Jacobs-Wagner
To achieve robust replication, bacteria must integrate cellular metabolism and cell wall growth. While these two processes have been well characterized, the nature and extent of cross-regulation between them is not well understood. Here, using classical genetics, CRISPRi, metabolomics, transcriptomics and chemical complementation approaches, we show that a loss of the master regulator Hfq in Caulobacter crescentus alters central metabolism and results in cell shape defects in a nutrient-dependent manner. We demonstrate that the cell morphology phenotype in the hfq deletion mutant is attributable to a disruption of α-ketoglutarate (KG) homeostasis...
August 2017: PLoS Genetics
Sung Sun Yim, Jae Woong Choi, Se Hwa Lee, Eun Jung Jeon, Wook-Jin Chung, Ki Jun Jeong
Xylonic acid is a promising platform chemical with various applications in the fields of food, pharmaceuticals, and agriculture. However, in the current process, xylonic acid is mainly produced by the conversion of xylose, whose preparation requires substantial cost and time. Here, Corynebacterium glutamicum is engineered for the consolidated bioconversion of hemicellulosic biomass (xylan) into xylonic acid in a single cultivation. First, for the efficient conversion of xylose to xylonic acid, xylose dehydrogenase (Xdh) and xylonolactonase (XylC) from Caulobacter crescentus are evaluated together with a previously optimized xylose transporter module (XylE of Escherichia coli), and cells expressing xdh and xylE genes with an optimized expression system can produce xylonic acid from xylose with 100% conversion yield...
August 11, 2017: Biotechnology Journal
Eric M Danhart, Marina Bakhtina, William A Cantara, Alexandra B Kuzmishin, Xiao Ma, Brianne L Sanford, Marija Košutić, Yuki Goto, Hiroaki Suga, Kotaro Nakanishi, Ronald Micura, Mark P Foster, Karin Musier-Forsyth
Molecular sieves ensure proper pairing of tRNAs and amino acids during aminoacyl-tRNA biosynthesis, thereby avoiding detrimental effects of mistranslation on cell growth and viability. Mischarging errors are often corrected through the activity of specialized editing domains present in some aminoacyl-tRNA synthetases or via single-domain trans-editing proteins. ProXp-ala is a ubiquitous trans-editing enzyme that edits Ala-tRNA(Pro), the product of Ala mischarging by prolyl-tRNA synthetase, although the structural basis for discrimination between correctly charged Pro-tRNA(Pro) and mischarged Ala-tRNA(Ala) is unclear...
August 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
Shiladitya Banerjee, Klevin Lo, Matthew K Daddysman, Alan Selewa, Thomas Kuntz, Aaron R Dinner, Norbert F Scherer
Cell size is specific to each species and impacts cell function. Various phenomenological models for cell size regulation have been proposed, but recent work in bacteria has suggested an 'adder' model, in which a cell increments its size by a constant amount between each division. However, the coupling between cell size, shape and constriction remains poorly understood. Here, we investigate size control and the cell cycle dependence of bacterial growth using multigenerational cell growth and shape data for single Caulobacter crescentus cells...
July 24, 2017: Nature Microbiology
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