scholarly journals Restoration and Modification of Magnetosome Biosynthesis by Internal Gene Acquisition in a Magnetotactic Bacterium

2020 ◽  
Vol 15 (12) ◽  
pp. 2000278 ◽  
Author(s):  
Atsushi Arakaki ◽  
Mayu Goto ◽  
Mina Maruyama ◽  
Takuto Yoda ◽  
Masayoshi Tanaka ◽  
...  
Keyword(s):  
Magnetotactic Bacterium ◽  
Gene Acquisition ◽  
Internal Gene

Examining the chemistry and magnetism of magnetotactic bacterium Candidatus Magnetovibrio blakemorei strain MV-1 using scanning transmission X-ray microscopy

2012 ◽  
Vol 300-301 ◽  
pp. 14-23 ◽  
Author(s):  
Samanbir S. Kalirai ◽  
Karen P. Lam ◽  
Dennis A. Bazylinski ◽  
Ulysses Lins ◽  
Adam P. Hitchcock
Keyword(s):  
Magnetotactic Bacterium ◽  
X Ray ◽  
Scanning Transmission

Magnetovibrio blakemorei gen. nov., sp. nov., a magnetotactic bacterium ( Alphaproteobacteria : Rhodospirillaceae ) isolated from a salt marsh

2013 ◽  
Vol 63 (Pt_5) ◽  
pp. 1824-1833 ◽  
Author(s):  
Dennis A. Bazylinski ◽  
Timothy J. Williams ◽  
Christopher T. Lefèvre ◽  
Denis Trubitsyn ◽  
Jiasong Fang ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Electron Acceptor ◽  
Anaerobic Growth ◽  
Rrna Gene ◽  
Magnetotactic Bacterium ◽  
Single Chain ◽  
Circular Chromosome ◽  
Terminal Electron Acceptor ◽  
Content Type ◽  
Link Type

A magnetotactic bacterium, designated strain MV-1T, was isolated from sulfide-rich sediments in a salt marsh near Boston, MA, USA. Cells of strain MV-1T were Gram-negative, and vibrioid to helicoid in morphology. Cells were motile by means of a single polar flagellum. The cells appeared to display a transitional state between axial and polar magnetotaxis: cells swam in both directions, but generally had longer excursions in one direction than the other. Cells possessed a single chain of magnetosomes containing truncated hexaoctahedral crystals of magnetite, positioned along the long axis of the cell. Strain MV-1T was a microaerophile that was also capable of anaerobic growth on some nitrogen oxides. Salinities greater than 10 % seawater were required for growth. Strain MV-1T exhibited chemolithoautotrophic growth on thiosulfate and sulfide with oxygen as the terminal electron acceptor (microaerobic growth) and on thiosulfate using nitrous oxide (N2O) as the terminal electron acceptor (anaerobic growth). Chemo-organoautotrophic and methylotrophic growth was supported by formate under microaerobic conditions. Autotrophic growth occurred via the Calvin–Benson–Bassham cycle. Chemo-organoheterotrophic growth was supported by various organic acids and amino acids, under microaerobic and anaerobic conditions. Optimal growth occurred at pH 7.0 and 26–28 °C. The genome of strain MV-1T consisted of a single, circular chromosome, about 3.7 Mb in size, with a G+C content of 52.9–53.5 mol%.Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MV-1T belongs to the family Rhodospirillaceae within the Alphaproteobacteria , but is not closely related to the genus Magnetospirillum . The name Magnetovibrio blakemorei gen. nov., sp. nov. is proposed for strain MV-1T. The type strain of Magnetovibrio blakemorei is MV-1T ( = ATCC BAA-1436T  = DSM 18854T).

Gene acquisition in HIV and SIV

Nature ◽  
1996 ◽  
Vol 383 (6601) ◽  
pp. 586-587 ◽  
Author(s):  
Paul M. Sharp ◽  
Elizabeth Bailes ◽  
Mario Stevenson ◽  
Michael Emerman ◽  
Beatrice H. Hahn
Keyword(s):  
Gene Acquisition

scholarly journals Emergence of protocellular growth laws

2007 ◽  
Vol 362 (1486) ◽  
pp. 1841-1845 ◽  
Author(s):  
Tristan Rocheleau ◽  
Steen Rasmussen ◽  
Peter E Nielsen ◽  
Martin N Jacobi ◽  
Hans Ziock
Keyword(s):  
Kinetic Studies ◽  
Product Inhibition ◽  
Replication Process ◽  
Gene Replication ◽  
Math Biol ◽  
Curr Opin Cell Biol ◽  
Growth Laws ◽  
Internal Gene ◽  
The Many ◽  
The Individual

Template-directed replication is known to obey a parabolic growth law due to product inhibition (Sievers & Von Kiedrowski 1994 Nature 369 , 221; Lee et al . 1996 Nature 382 , 525; Varga & Szathmáry 1997 Bull. Math. Biol . 59 , 1145). We investigate a template-directed replication with a coupled template catalysed lipid aggregate production as a model of a minimal protocell and show analytically that the autocatalytic template–container feedback ensures balanced exponential replication kinetics; both the genes and the container grow exponentially with the same exponent. The parabolic gene replication does not limit the protocellular growth, and a detailed stoichiometric control of the individual protocell components is not necessary to ensure a balanced gene–container growth as conjectured by various authors (Gánti 2004 Chemoton theory ). Our analysis also suggests that the exponential growth of most modern biological systems emerges from the inherent spatial quality of the container replication process as we show analytically how the internal gene and metabolic kinetics determine the cell population's generation time and not the growth law (Burdett & Kirkwood 1983 J. Theor. Biol . 103 , 11–20; Novak et al . 1998 Biophys. Chem . 72 , 185–200; Tyson et al . 2003 Curr. Opin. Cell Biol . 15 , 221–231). Previous extensive replication reaction kinetic studies have mainly focused on template replication and have not included a coupling to metabolic container dynamics (Stadler et al . 2000 Bull. Math. Biol . 62 , 1061–1086; Stadler & Stadler 2003 Adv. Comp. Syst . 6 , 47). The reported results extend these investigations. Finally, the coordinated exponential gene–container growth law stemming from catalysis is an encouraging circumstance for the many experimental groups currently engaged in assembling self-replicating minimal artificial cells (Szostak 2001 et al . Nature 409 , 387–390; Pohorille & Deamer 2002 Trends Biotech . 20 123–128; Rasmussen et al . 2004 Science 303 , 963–965; Szathmáry 2005 Nature 433 , 469–470; Luisi et al . 2006 Naturwissenschaften 93 , 1–13). 1

scholarly journals Pressure-Ineduced Activation of the Swimming Motility of Magnetotactic Bacterium

2018 ◽  
Vol 114 (3) ◽  
pp. 324a
Author(s):  
Masayoshi Nishiyama ◽  
Ruan Juanfang ◽  
Takayuki Kato ◽  
Toru Minamino ◽  
Keiichi Namba ◽  
...  
Keyword(s):  
Magnetotactic Bacterium ◽  
Swimming Motility

scholarly journals Evaluation of Live Attenuated Influenza A Virus H6 Vaccines in Mice and Ferrets

2008 ◽  
Vol 83 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Zhongying Chen ◽  
Celia Santos ◽  
Amy Aspelund ◽  
Laura Gillim-Ross ◽  
Hong Jin ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Serum Antibody ◽  
Cross Reactivity ◽  
Phenotypic Properties ◽  
Vaccine Candidates ◽  
Virus Challenge ◽  
Avian Influenza A Virus ◽  
Internal Gene

ABSTRACT Avian influenza A virus A/teal/HK/W312/97 (H6N1) possesses seven gene segments that are highly homologous to those of highly pathogenic human influenza H5N1 viruses, suggesting that a W312-like H6N1 virus might have been involved in the generation of the A/HK/97 H5N1 viruses. The continuous circulation and reassortment of influenza H6 subtype viruses in birds highlight the need to develop an H6 vaccine to prevent potential influenza pandemics caused by the H6 viruses. Based on the serum antibody cross-reactivity data obtained from 14 different H6 viruses from Eurasian and North American lineages, A/duck/HK/182/77, A/teal/HK/W312/97, and A/mallard/Alberta/89/85 were selected to produce live attenuated H6 candidate vaccines. Each of the H6 vaccine strains is a 6:2 reassortant ca virus containing HA and NA gene segments from an H6 virus and the six internal gene segments from cold-adapted A/Ann Arbor/6/60 (AA ca), the master donor virus that is used to make live attenuated influenza virus FluMist (intranasal) vaccine. All three H6 vaccine candidates exhibited phenotypic properties of temperature sensitivity (ts), ca, and attenuation (att) conferred by the internal gene segments from AA ca. Intranasal administration of a single dose of the three H6 ca vaccine viruses induced neutralizing antibodies in mice and ferrets and fully protected mice and ferrets from homologous wild-type (wt) virus challenge. Among the three H6 vaccine candidates, the A/teal/HK/W312/97 ca virus provided the broadest cross-protection against challenge with three antigenically distinct H6 wt viruses. These data support the rationale for further evaluating the A/teal/HK/W312/97 ca vaccine in humans.

scholarly journals Acquisition of multidrug resistance transposon Tn6061 and IS6100-mediated large chromosomal inversions in Pseudomonas aeruginosa clinical isolates

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1448-1458 ◽  
Author(s):  
Sébastien Coyne ◽  
Patrice Courvalin ◽  
Marc Galimand
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Chromosomal Inversions ◽  
Gene Acquisition ◽  
Drug Classes ◽  
Horizontal Acquisition

Pseudomonas aeruginosa is a major human opportunistic pathogen, especially for patients in intensive care units or with cystic fibrosis. Multidrug resistance is a common feature of this species. In a previous study we detected the ant(4′)-IIb gene in six multiresistant clinical isolates of P. aeruginosa, and determination of the environment of the gene led to characterization of Tn6061. This 26 586 bp element, a member of the Tn3 family of transposons, carried 10 genes conferring resistance to six drug classes. The ant(4′)-IIb sequence was flanked by directly repeated copies of ISCR6 in all but one of the strains studied, consistent with ISCR6-mediated gene acquisition. Tn6061 was chromosomally located in six strains and plasmid-borne in the remaining isolate, suggesting horizontal acquisition. Duplication-insertion of IS6100, that ended Tn6061, was responsible for large chromosomal inversions. Acquisition of Tn6061 and chromosomal inversions are further examples of intricate mechanisms that contribute to the genome plasticity of P. aeruginosa.

scholarly journals Experimental Evolution of Legume Symbionts: What Have We Learnt?

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 339 ◽  
Author(s):  
Ginaini Grazielli Doin de Moura ◽  
Philippe Remigi ◽  
Catherine Masson-Boivin ◽  
Delphine Capela
Keyword(s):  
Experimental Evolution ◽  
Nitrogen Fixing ◽  
Plant Selection ◽  
Cell Infection ◽  
Symbiotic Gene ◽  
Symbiotic Plasmid ◽  
Evolutionary Scenario ◽  
Gene Acquisition ◽  
Regulatory Circuits ◽  
Horizontal Transfers

Rhizobia, the nitrogen-fixing symbionts of legumes, are polyphyletic bacteria distributed in many alpha- and beta-proteobacterial genera. They likely emerged and diversified through independent horizontal transfers of key symbiotic genes. To replay the evolution of a new rhizobium genus under laboratory conditions, the symbiotic plasmid of Cupriavidus taiwanensis was introduced in the plant pathogen Ralstonia solanacearum, and the generated proto-rhizobium was submitted to repeated inoculations to the C. taiwanensis host, Mimosa pudica L. This experiment validated a two-step evolutionary scenario of key symbiotic gene acquisition followed by genome remodeling under plant selection. Nodulation and nodule cell infection were obtained and optimized mainly via the rewiring of regulatory circuits of the recipient bacterium. Symbiotic adaptation was shown to be accelerated by the activity of a mutagenesis cassette conserved in most rhizobia. Investigating mutated genes led us to identify new components of R. solanacearum virulence and C. taiwanensis symbiosis. Nitrogen fixation was not acquired in our short experiment. However, we showed that post-infection sanctions allowed the increase in frequency of nitrogen-fixing variants among a non-fixing population in the M. pudica–C. taiwanensis system and likely allowed the spread of this trait in natura. Experimental evolution thus provided new insights into rhizobium biology and evolution.

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