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Alejandro M Labella, M Dolores Castro, Manuel Manchado, Juan J Borrego
Phylogenetic relationships between species in the genus Photobacterium have been poorly studied despite pathogenic and ecological relevance of some of its members. This is the first phylogenetic study that includes new species of Photobacterium (validated or not) that have not been included in any of the previously described clades, using 16S rRNA sequences and multilocus sequence analysis (MLSA) in concatenated sequences of gyrB , gapA , topA , ftsZ and mreB housekeeping genes. Sequence analysis has been implemented using Maximum-parsimony (MP), Neighbour-joining (NJ) and Maximum likelihood (ML) treeing methods and the predicted evolutionary relationship between the Photobacterium clades was established on the basis of bootstrap values of >75% for 16S rRNA sequences and MLSA...
March 12, 2018: Microorganisms
Handuo Shi, Benjamin P Bratton, Zemer Gitai, Kerwyn Casey Huang
Cell shape matters across the kingdoms of life, and cells have the remarkable capacity to define and maintain specific shapes and sizes. But how are the shapes of micron-sized cells determined from the coordinated activities of nanometer-sized proteins? Here, we review general principles that have surfaced through the study of rod-shaped bacterial growth. Imaging approaches have revealed that polymers of the actin homolog MreB play a central role. MreB both senses and changes cell shape, thereby generating a self-organizing feedback system for shape maintenance...
March 8, 2018: Cell
Karabi Saikia, Nitin Chaudhary
Antimicrobial peptides are critical components of defense systems in living forms. The activity is conferred largely by the selective membrane-permeabilizing ability. In our earlier work, we derived potent antimicrobial peptides from the 9-residue long, N-terminal amphipathic helix of E. coli MreB protein. The peptides display broad-spectrum activity, killing not only Gram-positive and Gram-negative bacteria but opportunistic fungus, Candida albicans as well. These results proved that membrane-binding stretches of bacterial proteins could turn out to be self-harming when applied from outside...
February 23, 2018: Biochemical and Biophysical Research Communications
Ryosuke Ikebe, Yuri Kuwabara, Taiki Chikada, Hironori Niki, Daisuke Shiomi
Rod shape of bacterial cells such as Escherichia coli is mainly regulated by a supramolecular complex called elongasome including MreB actin. Deletion of the mreB gene in rod-shaped bacterium E. coli results in round-shaped cells. RodZ was isolated as a determinant of rod shape in E. coli, Caulobacter crescentus and Bacillus subtilis and it has been shown to be an interaction partner and a regulator of assembly of MreB through its cytoplasmic domain. As opposed to functions of the N-terminal cytoplasmic domain of RodZ, functions of the C-terminal periplasmic domain including a disordered region are still unclear...
February 26, 2018: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Saman Hussain, Carl N Wivagg, Piotr Szwedziak, Felix Wong, Kaitlin Schaefer, Thierry Izoré, Lars D Renner, Matthew J Holmes, Yingjie Sun, Alexandre W Bisson-Filho, Suzanne Walker, Ariel Amir, Jan Löwe, Ethan C Garner
MreB is essential for rod shape in many bacteria. Membrane-associated MreB filaments move around the rod circumference, helping to insert cell wall in the radial direction to reinforce rod shape. To understand how oriented MreB motion arises, we altered the shape of Bacillus subtilis . MreB motion is isotropic in round cells, and orientation is restored when rod shape is externally imposed. Stationary filaments orient within protoplasts, and purified MreB tubulates liposomes in vitro , orienting within tubes...
February 22, 2018: ELife
Guo Fu, Jigar N Bandaria, Anne Valérie Le Gall, Xue Fan, Ahmet Yildiz, Tâm Mignot, David R Zusman, Beiyan Nan
MreB is a bacterial actin that is important for cell shape and cell wall biosynthesis in many bacterial species. MreB also plays crucial roles in Myxococcus xanthus gliding motility, but the underlying mechanism remains unknown. Here we tracked the dynamics of single MreB particles in M. xanthus using single-particle tracking photoactivated localization microscopy. We found that a subpopulation of MreB particles moves rapidly along helical trajectories, similar to the movements of the MotAB-like gliding motors...
February 20, 2018: Proceedings of the National Academy of Sciences of the United States of America
Yujie Fang, Aiping Chen, Hang Dai, Ying Huang, Biao Kan, Duochun Wang
A Gram-stain-negative, facultatively anaerobic strain, designated FJ201301T , was isolated from aquaculture water collected from Fujian province, China. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain FJ201301T belonged to the genus Vibrio, formed a distinct cluster with Vibriocincinnatiensis ATCC 35912T and shared the highest similarity with Vibriosalilacus CGMCC 1.12427T . A 15 bp insertion found in the 16S rRNA gene was a significant marker that distinguished strain FJ201301T from several phylogenetic neighbours (e...
February 13, 2018: International Journal of Systematic and Evolutionary Microbiology
João M Monteiro, Ana R Pereira, Nathalie T Reichmann, Bruno M Saraiva, Pedro B Fernandes, Helena Veiga, Andreia C Tavares, Margarida Santos, Maria T Ferreira, Vânia Macário, Michael S VanNieuwenhze, Sérgio R Filipe, Mariana G Pinho
Peptidoglycan is the main component of the bacterial wall and protects cells from the mechanical stress that results from high intracellular turgor. Peptidoglycan biosynthesis is very similar in all bacteria; bacterial shapes are therefore mainly determined by the spatial and temporal regulation of peptidoglycan synthesis rather than by the chemical composition of peptidoglycan. The form of rod-shaped bacteria, such as Bacillus subtilis or Escherichia coli, is generated by the action of two peptidoglycan synthesis machineries that act at the septum and at the lateral wall in processes coordinated by the cytoskeletal proteins FtsZ and MreB, respectively...
February 14, 2018: Nature
Clara López-Hermoso, Rafael R de la Haba, Cristina Sánchez-Porro, Antonio Ventosa
Ten Gram-strain-negative, facultatively anaerobic, moderately halophilic bacterial strains, designated AL184T, IB560, IB563, IC202, IC317, MA421, ML277, ML318, ML328A and ML331, were isolated from water ponds of five salterns located in Spain. The cells were motile, curved rods and oxidase and catalase positive. All of them grew optimally at 37°C, at pH 7.2-7.4 and in the presence of 7.5% (w/v) NaCl. Based on phylogenetic analyses of the 16S rRNA, the isolates were most closely related to Salinivibrio sharmensis BAGT (99...
December 21, 2017: Systematic and Applied Microbiology
Handuo Shi, Alexandre Colavin, Marty Bigos, Carolina Tropini, Russell D Monds, Kerwyn Casey Huang
Size is a universally defining characteristic of all living cells and tissues and is intrinsically linked with cell genotype, growth, and physiology. Many mutations have been identified to alter cell size, but pleiotropic effects have largely hampered our ability to probe how cell size specifically affects fundamental cellular properties, such as DNA content and intracellular localization. To systematically interrogate the impact of cell morphology on bacterial physiology, we used fluorescence-activated cell sorting to enrich a library of hundreds of Escherichia coli mutants in the essential cytoskeletal protein MreB for subtle changes in cell shape, cumulatively spanning ∼5-fold variation in average cell volume...
November 20, 2017: Current Biology: CB
Satoshi Matsuoka
Glyceroglycolipids are very important in Gram-positive bacteria and cyanobacteria. In Bacillus subtilis, a model organism for the Gram-positive bacteria, the ugtP mutant, which lacks glyceroglucolipids, shows abnormal morphology. Lack of glucolipids has many consequences: abnormal localization of the cytoskeletal protein MreB and activation of some extracytoplasmic function (ECF) sigma factors (σ(M), σ(V) and σ(X)) in the log phase are two examples. Conversely, the expression of monoglucosyldiacylglycerol (MGlcDG) by 1,2-diacylglycerol 3-glucosyltransferase from Acholeplasma laidlawii (alMGS) almost completely suppresses the ugtP disruptant phenotype...
October 6, 2017: Genes & Genetic Systems
Sutharsan Govindarajan, Orna Amster-Choder
The Sec system is responsible for protein insertion, translocation and secretion across membranes in all cells. The bacterial actin homolog MreB controls various processes, including cell wall synthesis, membrane organization and polarity establishment. Here we show that the two systems genetically interact and that components of the Sec system, especially the SecA motor protein, are essential for spatiotemporal organization of MreB in E. coli, as evidenced by the accumulation of MreB at irregular sites in Sec-impaired cells...
September 2017: PLoS Genetics
Pengzhi Wu, Xiaodan Liu, Lingna Yang, Yitong Sun, Qingguo Gong, Jihui Wu, Yunyu Shi
In bacteria, small non-coding RNAs (sRNAs) could function in gene regulations under variable stress responses. DsrA is an ∼90-nucleotide Hfq-dependent sRNA found in Escherichia coli. It regulates the translation and degradation of multiple mRNAs, such as rpoS, hns, mreB and rbsD mRNAs. However, its functional structure and particularly how it regulates multiple mRNAs remain obscure. Using NMR, we investigated the solution structures of the full-length and isolated stem-loops of DsrA. We first solved the NMR structure of the first stem-loop (SL1), and further studied the melting process of the SL1 induced by the base-pairing with the rpoS mRNA and the A-form duplex formation of the DsrA/rpoS complex...
September 19, 2017: Nucleic Acids Research
Alejandro M Labella, David R Arahal, Teresa Lucena, Manuel Manchado, Dolores Castro, Juan J Borrego
Three bacterial strains were isolated from liver and spleen of diseased farmed redbanded seabream (Pagrus auriga) in south-west Spain. Their partial 16S rRNA gene sequences clustered within those of the genus Photobacterium, showing high similarity (98.6-99.3 %) to the type strains of Photobacterium iliopiscarium, P. piscicola, P. kishitanii, P. aquimaris and P. phosphoreum. Multilocus sequence analysis using six housekeeping genes (gapA, topA, mreB, ftsZ, gyrB and 16S rRNA) confirmed the new strains as forming an independent branch with a bootstrap value of 100, likely to represent a novel species...
September 21, 2017: International Journal of Systematic and Evolutionary Microbiology
Danielle M Heller, Mrinalini Tavag, Ann Hochschild
The toxin components of toxin-antitoxin modules, found in bacterial plasmids, phages, and chromosomes, typically target a single macromolecule to interfere with an essential cellular process. An apparent exception is the chromosomally encoded toxin component of the E. coli CbtA/CbeA toxin-antitoxin module, which can inhibit both cell division and cell elongation. A small protein of only 124 amino acids, CbtA, was previously proposed to interact with both FtsZ, a tubulin homolog that is essential for cell division, and MreB, an actin homolog that is essential for cell elongation...
September 2017: PLoS Genetics
Xiao-Ran Jiang, Zhi-Hao Yao, Guo-Qiang Chen
Bacterial morphology is decided by cytoskeleton protein MreB and cell division protein FtsZ encoded by essential genes mreB and ftsZ, respectively. Inactivating mreB and ftsZ lead to increasing cell sizes and cell lengths, respectively, yet seriously reduce cell growth ability. Here we develop a temperature-responsible plasmid expression system for compensated expression of relevant gene(s) in mreB or ftsZ disrupted recombinants H. campaniensis LS21, allowing mreB or ftsZ disrupted recombinants to grow normally at 30°C in a bioreactor for 12h so that a certain cell density can be reached, followed by 36h cell size expansions or cell shape elongations at elevated 37°C at which the mreB and ftsZ encoded plasmid pTKmf failed to replicate in the recombinants and thus lost themselves...
November 2017: Metabolic Engineering
Micheline El Khoury, Jitendriya Swain, Guillaume Sautrey, Louis Zimmermann, Patrick Van Der Smissen, Jean-Luc Décout, Marie-Paule Mingeot-Leclercq
Some bacterial proteins involved in cell division and oxidative phosphorylation are tightly bound to cardiolipin. Cardiolipin is a non-bilayer anionic phospholipid found in bacterial inner membrane. It forms lipid microdomains located at the cell poles and division plane. Mechanisms by which microdomains are affected by membrane-acting antibiotics and the impact of these alterations on membrane properties and protein functions remain unclear. In this study, we demonstrated cardiolipin relocation and clustering as a result of exposure to a cardiolipin-acting amphiphilic aminoglycoside antibiotic, the 3',6-dinonyl neamine...
September 6, 2017: Scientific Reports
Robin Koch, Anne Kupczok, Karina Stucken, Judith Ilhan, Katrin Hammerschmidt, Tal Dagan
BACKGROUND: Filamentous cyanobacteria that differentiate multiple cell types are considered the peak of prokaryotic complexity and their evolution has been studied in the context of multicellularity origins. Species that form true-branching filaments exemplify the most complex cyanobacteria. However, the mechanisms underlying the true-branching morphology remain poorly understood despite of several investigations that focused on the identification of novel genes or pathways. An alternative route for the evolution of novel traits is based on existing phenotypic plasticity...
August 31, 2017: BMC Evolutionary Biology
Pauline Cordenonsi Bonez, Grazielle Guidolin Rossi, Jardel Rodrigo Bandeira, Andiara Prates Ramos, Caren Rigon Mizdal, Vanessa Albertina Agertt, Eloísa Salete Segatto Dalla Nora, Márcia Ebling de Souza, Camilla Fillippi Dos Santos Alves, Fallon Siqueira Dos Santos, André Gündel, Rodrigo de Almeida Vaucher, Roberto Christ Vianna Santos, Marli Matiko Anraku de Campos
Bacterial biofilms are involved in various medical infections and for this reason it is of great importance understanding adhesion mechanisms of involved microorganisms is essential to develop new strategies of prevention and control. Different approaches have been used for preventing biofilm related infections in health care settings, such as use of surface coatings agents in medical implants. In this context, is necessary to explore new compounds with anti-biofilm activity. Thus, this study evaluated for the first time the action of A22 against biofilms of Pseudomonas aeruginosa PAO1 strain and multi-resistant clinical isolates on biotic and abiotic surfaces...
October 2017: Microbial Pathogenesis
Felix Wong, Lars D Renner, Gizem Özbaykal, Jayson Paulose, Douglas B Weibel, Sven van Teeffelen, Ariel Amir
The shapes of most bacteria are imparted by the structures of their peptidoglycan cell walls, which are determined by many dynamic processes that can be described on various length scales ranging from short-range glycan insertions to cellular-scale elasticity(1-11). Understanding the mechanisms that maintain stable, rod-like morphologies in certain bacteria has proved to be challenging due to an incomplete understanding of the feedback between growth and the elastic and geometric properties of the cell wall(3,4,12-14)...
July 24, 2017: Nature Microbiology
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