Hydrodynamic attraction of swimming microorganisms by surfaces (2008)
Berke, Allison P., Turner, Linda, Berg, Howard C., Lauga, Eric
Cells swimming in confined environments are attracted by surfaces. We measure the steady-state distribution of smooth-swimming bacteria (Escherichia coli) between two glass plates. In agreement with...
Novel ultrastructures of Treponema primitia and their implications for motility (2008)
Murphy, Gavin E., Matson, Eric G., Leadbetter, Jared R., Berg, Howard C., Jensen, Grant J.
Members of the bacterial phylum Spirochaetes are generally helical cells propelled by periplasmic flagella. The spirochete Treponema primitia is interesting because of its mutualistic role in the...
The Complete Genome and Proteome of Mycoplasma mobile (2004)
Jaffe, Jacob D., Stange-Thomann, Nicole, Smith, Cherylyn, DeCaprio, David, Fisher, Sheila, Butler, Jonathan, ...
Although often considered “minimal” organisms, mycoplasmas show a wide range of diversity with respect to host environment, phenotypic traits, and pathogenicity. Here we report the complete...
MotA protein of E. coli is a proton-conducting component of the flagellar motor (1990)
Blair, David F., Berg, Howard C.
A number of mutants of mofA, a gene necessary for flagellar rotation in E. coli, were isolated and characterized. Many mutations were dominant, owing to competition between functional and...
Temporal comparisons in bacterial chemotaxis (1986)
Segall, Jeffrey E., Block, Steven M., Berg, Howard C.
Responses of tethered cells of Escherichia coli to impulse, step, exponential-ramp or exponentiated sine-wave stimuli are internally consistent, provided that allowance is made for the nonlinear...
Chimeric chemosensory transducers of Escherichia coli (1985)
Krikos, Alexandra, Conley, M. Patricia, Boyd, Alan, Berg, Howard C., Simon, Melvin I.
The tar and tsr genes of Escherichia coli encode homologous transducer proteins that mediate distinct chemotactic responses. We report here the construction of two tasr chimeric genes in which the 5'...
Chemotactic signaling in filamentous cells of Escherichia coli (1985)
Segall, Jeffrey E., Ishihara, Akira, Berg, Howard C.
Video techniques were used to record chemotactic responses of filamentous cells of Escherichia coli stimulated iontophoretically with aspartate. Long, nonseptate cells were produced from polyhook...
Chemical modification of Streptococcus flagellar motors (1984)
Conley, M. Patricia, Berg, Howard C.
Video techniques were used to record changes in motility of cells of Streptococcus sp. strain V4051 exposed to a variety of protein modification reagents. Starved cells were tethered to glass by a...
Coordination of flagella on filamentous cells of Escherichia coli (1983)
Ishihara, Akira, Segall, Jeffrey E., Block, Steven M., Berg, Howard C.
Video techniques were used to study the coordination of different flagella on single filamentous cells of Escherichia coli. Filamentous, nonseptate cells were produced by introducing a cell division...
Adaptation kinetics in bacterial chemotaxis (1983)
Block, Steven M., Segall, Jeffrey E., Berg, Howard C.
Cells of Escherichia coli, tethered to glass by a single flagellum, were subjected to constant flow of a medium containing the attractant alpha-methyl-DL-aspartate. The concentration of this chemical...
Gliding motility of Cytophaga sp. strain U67 (1982)
Lapidus, I. Richard, Berg, Howard C.
Video techniques were used to analyze the motion of the gliding bacterium Cytophaga sp. strain U67. Cells moved singly on glass along the long axis at a speed of about 2 micrometers/s, advancing,...
Control of direction of flagellar rotation in bacterial chemotaxis
Scharf, Birgit E., Fahrner, Karen A., Turner, Linda, Berg, Howard C.
The motile behavior of the bacterium Escherichia coli depends on the direction of rotation of its flagellar motors. Binding of the phosphorylated signaling molecule CheY to a motor component FliM is...
Flagellar determinants of bacterial sensitivity to χ-phage
Samuel, Aravinthan D. T., Pitta, Thomas P., Ryu, William S., Danese, Paul N., Leung, Edward C. W., Berg, Howard C.
Bacteriophage χ is known to infect motile strains of enteric bacteria by adsorbing randomly along the length of a flagellar filament and then injecting its DNA into the bacterial cell at the...
Berry, Richard M., Berg, Howard C.
A cell of the bacterium Escherichia coli was tethered covalently to a glass coverslip by a single flagellum, and its rotation was stopped by using optical tweezers. The tweezers acted directly on the...
Direct observation of extension and retraction of type IV pili
Skerker, Jeffrey M., Berg, Howard C.
Type IV pili are thin filaments that extend from the poles of a diverse group of bacteria, enabling them to move at speeds of a few tenths of a micrometer per second. They are required for twitching...
Real-Time Imaging of Fluorescent Flagellar Filaments
Turner, Linda, Ryu, William S., Berg, Howard C.
Bacteria swim by rotating flagellar filaments that are several micrometers long, but only about 20 nm in diameter. The filaments can exist in different polymorphic forms, having distinct values of...
CheZ Has No Effect on Flagellar Motors Activated by CheY13DK106YW
Scharf, Birgit E., Fahrner, Karen A., Berg, Howard C.
The behaviors of both cheZ-deleted and wild-type cells of Escherichia coli were found to be very sensitive to the level of expression of CheZ, a protein known to accelerate the dephosphorylation of...
Receptor sensitivity in bacterial chemotaxis
Sourjik, Victor, Berg, Howard C.
Chemoreceptors in Escherichia coli are coupled to the flagella by a labile phosphorylated intermediate, CheY∼P. Its activity can be inferred from the rotational bias of flagellar motors, but motor...
Sourjik, Victor, Berg, Howard C.
In Escherichia coli chemotaxis, signaling depends on modulation of the level of phosphorylation of CheY, a small protein that couples receptors and flagellar motors. Working in vivo, we used...
Force and Velocity of Mycoplasma mobile Gliding†
Miyata, Makoto, Ryu, William S., Berg, Howard C.
The effects of temperature and force on the gliding speed of Mycoplasma mobile were examined. Gliding speed increased linearly as a function of temperature from 0.46 μm/s at 11.5°C to 4.0 μm/s at...
The speed of the flagellar rotary motor of Escherichia coli varies linearly with protonmotive force
Gabel, Christopher V., Berg, Howard C.
A protonmotive force (pmf) across the cell's inner membrane powers the flagellar rotary motor of Escherichia coli. Speed is known to be proportional to pmf when viscous loads are heavy. Here we show...
Temporal Stimulation of Chemotaxis in Escherichia coli
Brown, Douglas A., Berg, Howard C.
We used the tracking microscope to study the chemotactic responses of E. coli to temporal gradients of L-glutamate generated in isotropic solutions by the action of the enzyme alanine...
Energetics of Gliding Motility in Mycoplasma mobile
Jaffe, Jacob D., Miyata, Makoto, Berg, Howard C.
Mycoplasma mobile glides on surfaces at up to 7 μm/s by an unknown mechanism. We studied the energetics that power gliding by using a novel, growth medium-free system. We found that cells could...
The Complete Genome and Proteome of Mycoplasma mobile
Jaffe, Jacob D., Stange-Thomann, Nicole, Smith, Cherylyn, DeCaprio, David, Fisher, Sheila, Butler, Jonathan, ...
Although often considered “minimal” organisms, mycoplasmas show a wide range of diversity with respect to host environment, phenotypic traits, and pathogenicity. Here we report the complete...
Liberman, Louisa, Berg, Howard C., Sourjik, Victor
Bacterial chemoreceptors are embedded in the inner cell membrane in tight clusters. We show that changes in receptor methylation that generate large changes in kinase activity have relatively little...
Single-cell FRET imaging of phosphatase activity in the Escherichia coli chemotaxis system
Two-component signaling systems, in which a receptor-coupled kinase is used to control the phosphorylation level of a response regulator, are commonly used in bacteria to sense their environment. In...
Moving Fluid with Bacterial Carpets
Darnton, Nicholas, Turner, Linda, Breuer, Kenneth, Berg, Howard C.
We activated a solid-fluid interface by attaching flagellated bacteria to a solid surface. We adsorbed swarmer cells of Serratia marcescens to polydimethylsiloxane or polystyrene. The cell bodies...
Osmotic stress mechanically perturbs chemoreceptors in Escherichia coli
Two-component signaling systems play a major role in the long-term adaptation of microorganisms to changes in osmolarity, but how osmoreceptors work is not well understood. Temporal changes in solute...
Shimizu, Thomas S., Delalez, Nicolas, Pichler, Klemens, Berg, Howard C.
We looked for a feedback system in Escherichia coli that might sense the rotational bias of flagellar motors and regulate the activity of the chemotaxis receptor kinase. Our search was based on the...
Control of direction of flagellar rotation in bacterial chemotaxis
Scharf, Birgit E., Fahrner, Karen A., Turner, Linda, Berg, Howard C.
The motile behavior of the bacterium Escherichia coli depends on the direction of rotation of its flagellar motors. Binding of the phosphorylated signaling molecule CheY to a motor component FliM is...
Flagellar determinants of bacterial sensitivity to χ-phage
Samuel, Aravinthan D. T., Pitta, Thomas P., Ryu, William S., Danese, Paul N., Leung, Edward C. W., Berg, Howard C.
Bacteriophage χ is known to infect motile strains of enteric bacteria by adsorbing randomly along the length of a flagellar filament and then injecting its DNA into the bacterial cell at the...
Berry, Richard M., Berg, Howard C.
A cell of the bacterium Escherichia coli was tethered covalently to a glass coverslip by a single flagellum, and its rotation was stopped by using optical tweezers. The tweezers acted directly on the...
Direct observation of extension and retraction of type IV pili
Skerker, Jeffrey M., Berg, Howard C.
Type IV pili are thin filaments that extend from the poles of a diverse group of bacteria, enabling them to move at speeds of a few tenths of a micrometer per second. They are required for twitching...
Real-Time Imaging of Fluorescent Flagellar Filaments
Turner, Linda, Ryu, William S., Berg, Howard C.
Bacteria swim by rotating flagellar filaments that are several micrometers long, but only about 20 nm in diameter. The filaments can exist in different polymorphic forms, having distinct values of...
CheZ Has No Effect on Flagellar Motors Activated by CheY13DK106YW
Scharf, Birgit E., Fahrner, Karen A., Berg, Howard C.
The behaviors of both cheZ-deleted and wild-type cells of Escherichia coli were found to be very sensitive to the level of expression of CheZ, a protein known to accelerate the dephosphorylation of...
Receptor sensitivity in bacterial chemotaxis
Sourjik, Victor, Berg, Howard C.
Chemoreceptors in Escherichia coli are coupled to the flagella by a labile phosphorylated intermediate, CheY∼P. Its activity can be inferred from the rotational bias of flagellar motors, but motor...
Sourjik, Victor, Berg, Howard C.
In Escherichia coli chemotaxis, signaling depends on modulation of the level of phosphorylation of CheY, a small protein that couples receptors and flagellar motors. Working in vivo, we used...
Force and Velocity of Mycoplasma mobile Gliding†
Miyata, Makoto, Ryu, William S., Berg, Howard C.
The effects of temperature and force on the gliding speed of Mycoplasma mobile were examined. Gliding speed increased linearly as a function of temperature from 0.46 μm/s at 11.5°C to 4.0 μm/s at...
The speed of the flagellar rotary motor of Escherichia coli varies linearly with protonmotive force
Gabel, Christopher V., Berg, Howard C.
A protonmotive force (pmf) across the cell's inner membrane powers the flagellar rotary motor of Escherichia coli. Speed is known to be proportional to pmf when viscous loads are heavy. Here we show...
Temporal Stimulation of Chemotaxis in Escherichia coli
Brown, Douglas A., Berg, Howard C.
We used the tracking microscope to study the chemotactic responses of E. coli to temporal gradients of L-glutamate generated in isotropic solutions by the action of the enzyme alanine...
Energetics of Gliding Motility in Mycoplasma mobile
Jaffe, Jacob D., Miyata, Makoto, Berg, Howard C.
Mycoplasma mobile glides on surfaces at up to 7 μm/s by an unknown mechanism. We studied the energetics that power gliding by using a novel, growth medium-free system. We found that cells could...
The Complete Genome and Proteome of Mycoplasma mobile
Jaffe, Jacob D., Stange-Thomann, Nicole, Smith, Cherylyn, DeCaprio, David, Fisher, Sheila, Butler, Jonathan, ...
Although often considered “minimal” organisms, mycoplasmas show a wide range of diversity with respect to host environment, phenotypic traits, and pathogenicity. Here we report the complete...
Liberman, Louisa, Berg, Howard C., Sourjik, Victor
Bacterial chemoreceptors are embedded in the inner cell membrane in tight clusters. We show that changes in receptor methylation that generate large changes in kinase activity have relatively little...
Single-cell FRET imaging of phosphatase activity in the Escherichia coli chemotaxis system
Two-component signaling systems, in which a receptor-coupled kinase is used to control the phosphorylation level of a response regulator, are commonly used in bacteria to sense their environment. In...
Moving Fluid with Bacterial Carpets
Darnton, Nicholas, Turner, Linda, Breuer, Kenneth, Berg, Howard C.
We activated a solid-fluid interface by attaching flagellated bacteria to a solid surface. We adsorbed swarmer cells of Serratia marcescens to polydimethylsiloxane or polystyrene. The cell bodies...
Osmotic stress mechanically perturbs chemoreceptors in Escherichia coli
Two-component signaling systems play a major role in the long-term adaptation of microorganisms to changes in osmolarity, but how osmoreceptors work is not well understood. Temporal changes in solute...
Shimizu, Thomas S., Delalez, Nicolas, Pichler, Klemens, Berg, Howard C.
We looked for a feedback system in Escherichia coli that might sense the rotational bias of flagellar motors and regulate the activity of the chemotaxis receptor kinase. Our search was based on the...
On Torque and Tumbling in Swimming Escherichia coli▿ †
Darnton, Nicholas C., Turner, Linda, Rojevsky, Svetlana, Berg, Howard C.
Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor. When the motors of peritrichous cells turn counterclockwise (CCW), their filaments form...
Force-Extension Measurements on Bacterial Flagella: Triggering Polymorphic Transformations
Darnton, Nicholas C., Berg, Howard C.
Bacterial flagella can adopt several different helical shapes in response to varying environmental conditions. A geometric model by Calladine ascribes these discrete shape changes to cooperative...
Chen, Bryan G., Turner, Linda, Berg, Howard C.
We compared the abilities of media from agar plates surrounding swarming and nonswarming cells of Salmonella enterica serovar Typhimurium to wet a nonpolar surface by measuring the contact angles of...
Resurrection of the flagellar rotary motor near zero load
Flagellated bacteria, such as Escherichia coli, are propelled by helical flagellar filaments, each driven at its base by a reversible rotary motor, powered by a transmembrane proton flux. Torque is...
Modeling the chemotactic response of Escherichia coli to time-varying stimuli
Tu, Yuhai, Shimizu, Thomas S., Berg, Howard C.
In their natural environment, cells need to extract useful information from complex temporal signals that vary over a wide range of intensities and time scales. Here, we study how such signals are...
Bacterial Flagella Are Firmly Anchored▿
Darnton, Nicholas C., Berg, Howard C.
There are mutants of Salmonella enterica (with mutations in fliF and fliL) that shed flagella when they are swimming in a viscous medium or on the surface of soft agar. Filaments with hooks and the...