Dynamics in the Dual Fuel Flagellar Motor of Shewanella oneidensis MR-1

The presence and absence of periplasmic rings in bacterial flagellar motors correlates with stator type

eLife ◽

10.7554/elife.43487 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 17

Author(s):

Mohammed Kaplan ◽

Debnath Ghosal ◽

Poorna Subramanian ◽

Catherine M Oikonomou ◽

Andreas Kjaer ◽

...

Keyword(s):

Legionella Pneumophila ◽

Pathogenic Bacteria ◽

Bioinformatics Analysis ◽

Cell Envelope ◽

Shewanella Oneidensis ◽

Flagellar Motor ◽

Flagellar Motors ◽

A Cell ◽

Animal Hosts

The bacterial flagellar motor, a cell-envelope-embedded macromolecular machine that functions as a cellular propeller, exhibits significant structural variability between species. Different torque-generating stator modules allow motors to operate in different pH, salt or viscosity levels. How such diversity evolved is unknown. Here, we use electron cryo-tomography to determine the in situ macromolecular structures of three Gammaproteobacteria motors: Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis, providing the first views of intact motors with dual stator systems. Complementing our imaging with bioinformatics analysis, we find a correlation between the motor’s stator system and its structural elaboration. Motors with a single H+-driven stator have only the core periplasmic P- and L-rings; those with dual H+-driven stators have an elaborated P-ring; and motors with Na+ or Na+/H+-driven stators have both their P- and L-rings embellished. Our results suggest an evolution of structural elaboration that may have enabled pathogenic bacteria to colonize higher-viscosity environments in animal hosts.

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Stable sub-complexes observedin situsuggest a modular assembly pathway of the bacterial flagellar motor

10.1101/369405 ◽

2018 ◽

Cited By ~ 2

Author(s):

Mohammed Kaplan ◽

Poorna Subramanian ◽

Debnath Ghosal ◽

Catherine M. Oikonomou ◽

Sahand Pirbadian ◽

...

Keyword(s):

Legionella Pneumophila ◽

Self Assembly ◽

Protein Localization ◽

Shewanella Oneidensis ◽

Flagellar Motor ◽

Inner Membrane ◽

Assembly Mechanism ◽

Alternate Model ◽

Bacterial Flagellar Motor ◽

Spatio Temporal

AbstractThe self-assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio-temporal synchronization of gene expression, protein localization and association of a dozen or more unique components. InSalmonellaandEscherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with each subsequent component stabilizing the last. Here, using electron cryo-tomography of intactLegionella pneumophila,Pseudomonas aeruginosaandShewanella oneidensiscells, we observe stable outer-membrane-embedded sub-complexes of the flagellar motor. These sub-complexes consist of the periplasmic embellished P- and L-rings, in the absence of other flagellar components, and bend the membrane inward dramatically. Additionally, we also observe independent inner-membrane sub-complexes consisting of the C- and MS-rings and export apparatus. These results suggest an alternate model for flagellar motor assembly in which outer- and inner-membrane-associated sub-complexes form independently and subsequently join, enabling later steps of flagellar production to proceed.

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The structural complexity of the Gammaproteobacteria flagellar motor is related to the type of its torque-generating stators

10.1101/369397 ◽

2018 ◽

Cited By ~ 3

Author(s):

Mohammed Kaplan ◽

Debnath Ghosal ◽

Poorna Subramanian ◽

Catherine M. Oikonomou ◽

Andreas Kjær ◽

...

Keyword(s):

Legionella Pneumophila ◽

Pathogenic Bacteria ◽

Cell Envelope ◽

Shewanella Oneidensis ◽

Structural Complexity ◽

High Viscosity ◽

Flagellar Motor ◽

Flagellar Motors ◽

Wide Range ◽

A Cell

AbstractThe bacterial flagellar motor is a cell-envelope-embedded macromolecular machine that functions as a propeller to move the cell. Rather than being an invariant machine, the flagellar motor exhibits significant variability between species, allowing bacteria to adapt to, and thrive in, a wide range of environments. For instance, different torque-generating stator modules allow motors to operate in conditions with different pH and sodium concentrations and some motors are adapted to drive motility in high-viscosity environments. How such diversity evolved is unknown. Here we use electron cryo-tomography to determine thein situmacromolecular structures of the flagellar motors of three Gammaproteobacteria species:Legionella pneumophila,Pseudomonas aeruginosa, andShewanella oneidensisMR-1, providing the first views of intact motors with dual stator systems. Complementing our imaging with bioinformatics analysis, we find a correlation between the stator system of the motor and its structural complexity. Motors with a single H+-driven stator system have only the core P- and L-rings in their periplasm; those with dual H+-driven stator systems have an extra component elaborating their P-ring; and motors with Na+- (or dual Na+-H+)- driven stator systems have additional rings surrounding both their P- and L-rings. Our results suggest an evolution of structural complexity that may have enabled pathogenic bacteria likeL. pneumophilaandP. aeruginosato colonize higher-viscosity environments in animal hosts.

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RESEARCH OF INDICATORS OF A VEHICLE WITH A DIESEL WORKING ON DIESEL AND DIESEL GAS CYCLES USING THE MATHEMATICAL MODEL

Avtoshliakhovyk Ukrayiny ◽

10.33868/0365-8392-2020-1-261-14-19 ◽

2020 ◽

pp. 14-19

Author(s):

Serhii Kovbasenko ◽

Andriy Holyk ◽

Serhii Hutarevych

Keyword(s):

Mathematical Model ◽

Diesel Engine ◽

Environmental Performance ◽

Energy Performance ◽

Dual Fuel ◽

Fuel System ◽

Compressed Natural Gas ◽

Diesel Vehicles ◽

Diesel Cycle ◽

The Mathematical Model

The features of an advanced mathematical model of motion of a truck with a diesel engine operating on the diesel and diesel gas cycles are presented in the article. As a result of calculations using the mathematical model, a decrease in total mass emissions as a result of carbon monoxide emissions is observed due to a decrease in emissions of nitrogen oxides and emissions of soot in the diesel gas cycle compared to the diesel cycle. The mathematical model of a motion of a truck on a city driving cycle according to GOST 20306-90 allows to study the fuel-economic, environmental and energy indicators of a diesel and diesel gas vehicle. The results of the calculations on the mathematical model will make it possible to conclude on the feasibility of converting diesel vehicles to using compressed natural gas. Object of the study – the fuel-economic, environmental and energy performance diesel engine that runs on dual fuel system using CNG. Purpose of the study – study of changes in fuel, economic, environmental and energy performance of vehicles with diesel engines operating on diesel and diesel gas cycles, according to urban driving cycle modes. Method of the study – calculations on a mathematical model and comparison of results with road tests. Bench and road tests, results of calculations on the mathematical model of motion of a truck with diesel, working on diesel and diesel gas cycles, show the improvement of environmental performance of diesel vehicles during the converting to compressed natural gas in operation. Improvement of environmental performance is obtained mainly through the reduction of soot emissions and nitrogen oxides emissions from diesel gas cycle operations compared to diesel cycle operations. The results of the article can be used to further develop dual fuel system using CNG. Keywords: diesel engine, diesel gas engine, CNG

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