CH391L/S12/Locomotion - Revision history

Jeffrey E. Barrick: /* Gas Vesicles */

Jeffrey E. Barrick — Mon, 30 Apr 2012 15:04:51 GMT

Gas Vesicles

←Older revision		Revision as of 15:04, 30 April 2012
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	[[Image:Serratia gas vesicles.jpg \|right\| thumb \| 200px \| Conical gas vesicles in ''Serratia sp''<cite>Ramsey2011</cite> ]]		[[Image:Serratia gas vesicles.jpg \|right\| thumb \| 200px \| Conical gas vesicles in ''Serratia sp''<cite>Ramsey2011</cite> ]]

-	Some aquatic bacteria use hollow gas-filled vesicles to provide buoyancy and enable them regulate their position in the water column. Prototrophic bacteria may use the vesicles to find regions with appropriate light intensity<cite>Damerval1991</cite>, similarly aearobic bacteria may use them to float to oxygenated surface waters<cite>Beard2002</cite> . Gas vesicles are commonly observed and studied in aquatic cyanobacteria, but have recently been discovered in ''Serratia sp.'', an enterobacterium <cite>Ramsey2011</cite>. Typically 10-14 ''gvp'' genes are involved in formation of the hollow, gas-filled cylindrical structures with conical caps. It has been shown that gas vesicles from ''Anabaena'' are permeable to H<sub>2</sub>, N<sub>2</sub>, 0<sub>2</sub>, C0<sub>2</sub>, CO, CH<sub>4</sub>, and Ar <cite>Walsby1971</cite>.	+	Some aquatic bacteria use hollow gas-filled vesicles to provide buoyancy and enable them regulate their position in the water column. Prototrophic bacteria may use the vesicles to find regions with appropriate light intensity<cite>Damerval1991</cite>, similarly aearobic bacteria may use them to float to oxygenated surface waters<cite>Beard2002</cite> . Gas vesicles are commonly observed and studied in aquatic cyanobacteria, but have recently been discovered in ''Serratia sp.'', an enterobacterium <cite>Ramsey2011</cite>. Typically 10-14 ''gvp'' genes are involved in formation of the hollow, gas-filled cylindrical structures with conical caps. It has been shown that gas vesicles from ''Anabaena'' are permeable to H<sub>2</sub>, N<sub>2</sub>, O<sub>2</sub>, CO<sub>2</sub>, CO, CH<sub>4</sub>, and Ar <cite>Walsby1971</cite>.
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-	The 2009 Groningen igem team cloned the gas vesicle operon from ''Bacillus megaterium'' and put it under the control of an Arsenite sensitive promoter. In the presence of Arsenite the cells will make gas vesicles and become buoyant [http://2009.igem.org/Team:Groningen/Project Groningen 2009].	+


		+	The 2009 Groningen igem team cloned the gas vesicle operon from ''Bacillus megaterium'' and put it under the control of an Arsenite sensitive promoter. In the presence of Arsenite the cells will make gas vesicles and become buoyant [http://2009.igem.org/Team:Groningen/Project Groningen 2009].

	==Twitching Motility==		==Twitching Motility==

Erik Quandt at 18:21, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 18:21:20 GMT

←Older revision		Revision as of 18:21, 26 March 2012
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	[http://www.youtube.com/watch?v=m1vJKz_bV7U Video of ''Pseudomonas aeruginosa'' twitching movement]		[http://www.youtube.com/watch?v=m1vJKz_bV7U Video of ''Pseudomonas aeruginosa'' twitching movement]
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	==Gliding Motility==		==Gliding Motility==

Erik Quandt at 18:04, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 18:04:43 GMT

←Older revision		Revision as of 18:04, 26 March 2012
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-	===Chemotaxis===	+	===Flagellar Chemotaxis===

	[[Image:CheYp.png \|left\| thumb \| 200px\|Regulation of flagellar rotation<cite>Sweeney2011</cite>]]		[[Image:CheYp.png \|left\| thumb \| 200px\|Regulation of flagellar rotation<cite>Sweeney2011</cite>]]

Erik Quandt at 16:25, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 16:25:21 GMT

←Older revision		Revision as of 16:25, 26 March 2012
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-	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and deliver auxin (indole 3-acetic acid [IAA]) to promote root growth. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/~~Project_Chemotaxis_Testing~~ 2009 Team Auxin].	+	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and deliver auxin (indole 3-acetic acid [IAA]) to promote root growth. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Tour 2009 Team Auxin].

Erik Quandt at 16:18, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 16:18:07 GMT

←Older revision		Revision as of 16:18, 26 March 2012
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	Many species of bacteria including ''Pseudomonas aeruginosa'',''Neisseria gonorrhoeae'' and ''Myxoccocus xanthus'' use a Type IV pilus (T4P) system for motility. Cell propulsion by T4P involves pilus extension, attachment, and then pilus retraction. This process results in a jerky pattern of movement, hence the name "Twitching motility". Cells move at rates of 0.05 - 1 uM per second and close proximity to other cells is usually required for efficient movement. The process of pilus extension and retraction involves the ATP-dependent assembly or disassembly of PilA monomers in the pilus fiber.		Many species of bacteria including ''Pseudomonas aeruginosa'',''Neisseria gonorrhoeae'' and ''Myxoccocus xanthus'' use a Type IV pilus (T4P) system for motility. Cell propulsion by T4P involves pilus extension, attachment, and then pilus retraction. This process results in a jerky pattern of movement, hence the name "Twitching motility". Cells move at rates of 0.05 - 1 uM per second and close proximity to other cells is usually required for efficient movement. The process of pilus extension and retraction involves the ATP-dependent assembly or disassembly of PilA monomers in the pilus fiber.

-	~~[http://www.youtube.com/watch?v=m1vJKz_bV7U Video of ''Pseudomonas aeruginosa'' twitiching movement]~~
	[[Image:twitch3.jpg \|center\| thumb \| 200px \| Kearns 2010 ]]		[[Image:twitch3.jpg \|center\| thumb \| 200px \| Kearns 2010 ]]
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		+	[http://www.youtube.com/watch?v=m1vJKz_bV7U Video of ''Pseudomonas aeruginosa'' twitching movement]

	==Gliding Motility==		==Gliding Motility==

Erik Quandt at 16:15, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 16:15:28 GMT

←Older revision		Revision as of 16:15, 26 March 2012
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	[[Image:twitch4.jpg \|left\| thumb \| 150px \| Mattick 2002<cite>Mattick 2002</cite> ]]		[[Image:twitch4.jpg \|left\| thumb \| 150px \| Mattick 2002<cite>Mattick 2002</cite> ]]
	Many species of bacteria including ''Pseudomonas aeruginosa'',''Neisseria gonorrhoeae'' and ''Myxoccocus xanthus'' use a Type IV pilus (T4P) system for motility. Cell propulsion by T4P involves pilus extension, attachment, and then pilus retraction. This process results in a jerky pattern of movement, hence the name "Twitching motility". Cells move at rates of 0.05 - 1 uM per second and close proximity to other cells is usually required for efficient movement. The process of pilus extension and retraction involves the ATP-dependent assembly or disassembly of PilA monomers in the pilus fiber.		Many species of bacteria including ''Pseudomonas aeruginosa'',''Neisseria gonorrhoeae'' and ''Myxoccocus xanthus'' use a Type IV pilus (T4P) system for motility. Cell propulsion by T4P involves pilus extension, attachment, and then pilus retraction. This process results in a jerky pattern of movement, hence the name "Twitching motility". Cells move at rates of 0.05 - 1 uM per second and close proximity to other cells is usually required for efficient movement. The process of pilus extension and retraction involves the ATP-dependent assembly or disassembly of PilA monomers in the pilus fiber.
		+
		+	[http://www.youtube.com/watch?v=m1vJKz_bV7U Video of ''Pseudomonas aeruginosa'' twitiching movement]
	[[Image:twitch3.jpg \|center\| thumb \| 200px \| Kearns 2010 ]]		[[Image:twitch3.jpg \|center\| thumb \| 200px \| Kearns 2010 ]]

Erik Quandt at 16:12, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 16:12:01 GMT

←Older revision		Revision as of 16:12, 26 March 2012
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-	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and ~~used for food~~. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].	+	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and deliver auxin (indole 3-acetic acid [IAA]) to promote root growth. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].

Erik Quandt at 15:43, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 15:43:11 GMT

←Older revision		Revision as of 15:43, 26 March 2012
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	The rotation of the flagellum and the direction of movement is often regulated by sensory stimuli, allowing the cell to migrate towards attractive signals. In ''E.coli'' this is achieved through a signal transduction system that controls the phosphorylation state of the response regulator protein ''CheY''. In the absence CheY-P the flagellum rotates CWW in a "run" state. The presence of ''CheY-P'', induces a switch to CW rotation resulting in "tumbling" which randomly reorients the cell. When an attractant binds to a receptor it initiates a conformational change and downstream cascade that leads to suppression of CheA, a protein that normally phosphoryates ''CheY'' to ''CheY-P''. The absence of ''CheY-P'' causes the flagellum to remain in the "run" state leading to migration towards the signal. A third protein, ''CheZ'' helps regulate the circuit by preventing the accumulation of ''CheY-P'' through dephosphorylation.		The rotation of the flagellum and the direction of movement is often regulated by sensory stimuli, allowing the cell to migrate towards attractive signals. In ''E.coli'' this is achieved through a signal transduction system that controls the phosphorylation state of the response regulator protein ''CheY''. In the absence CheY-P the flagellum rotates CWW in a "run" state. The presence of ''CheY-P'', induces a switch to CW rotation resulting in "tumbling" which randomly reorients the cell. When an attractant binds to a receptor it initiates a conformational change and downstream cascade that leads to suppression of CheA, a protein that normally phosphoryates ''CheY'' to ''CheY-P''. The absence of ''CheY-P'' causes the flagellum to remain in the "run" state leading to migration towards the signal. A third protein, ''CheZ'' helps regulate the circuit by preventing the accumulation of ''CheY-P'' through dephosphorylation.
		+

	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and used for food. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].		The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and used for food. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].
Line 25:		Line 26:

	Some aquatic bacteria use hollow gas-filled vesicles to provide buoyancy and enable them regulate their position in the water column. Prototrophic bacteria may use the vesicles to find regions with appropriate light intensity<cite>Damerval1991</cite>, similarly aearobic bacteria may use them to float to oxygenated surface waters<cite>Beard2002</cite> . Gas vesicles are commonly observed and studied in aquatic cyanobacteria, but have recently been discovered in ''Serratia sp.'', an enterobacterium <cite>Ramsey2011</cite>. Typically 10-14 ''gvp'' genes are involved in formation of the hollow, gas-filled cylindrical structures with conical caps. It has been shown that gas vesicles from ''Anabaena'' are permeable to H<sub>2</sub>, N<sub>2</sub>, 0<sub>2</sub>, C0<sub>2</sub>, CO, CH<sub>4</sub>, and Ar <cite>Walsby1971</cite>.		Some aquatic bacteria use hollow gas-filled vesicles to provide buoyancy and enable them regulate their position in the water column. Prototrophic bacteria may use the vesicles to find regions with appropriate light intensity<cite>Damerval1991</cite>, similarly aearobic bacteria may use them to float to oxygenated surface waters<cite>Beard2002</cite> . Gas vesicles are commonly observed and studied in aquatic cyanobacteria, but have recently been discovered in ''Serratia sp.'', an enterobacterium <cite>Ramsey2011</cite>. Typically 10-14 ''gvp'' genes are involved in formation of the hollow, gas-filled cylindrical structures with conical caps. It has been shown that gas vesicles from ''Anabaena'' are permeable to H<sub>2</sub>, N<sub>2</sub>, 0<sub>2</sub>, C0<sub>2</sub>, CO, CH<sub>4</sub>, and Ar <cite>Walsby1971</cite>.
		+

	The 2009 Groningen igem team cloned the gas vesicle operon from ''Bacillus megaterium'' and put it under the control of an Arsenite sensitive promoter. In the presence of Arsenite the cells will make gas vesicles and become buoyant [http://2009.igem.org/Team:Groningen/Project Groningen 2009].		The 2009 Groningen igem team cloned the gas vesicle operon from ''Bacillus megaterium'' and put it under the control of an Arsenite sensitive promoter. In the presence of Arsenite the cells will make gas vesicles and become buoyant [http://2009.igem.org/Team:Groningen/Project Groningen 2009].

Erik Quandt at 15:34, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 15:34:10 GMT

←Older revision		Revision as of 15:34, 26 March 2012
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	[[Image:CheYp.png \|left\| thumb \| 200px\|Regulation of flagellar rotation<cite>Sweeney2011</cite>]]		[[Image:CheYp.png \|left\| thumb \| 200px\|Regulation of flagellar rotation<cite>Sweeney2011</cite>]]

-	The rotation of the flagellum and the direction of movement is often regulated by sensory stimuli, allowing the cell to migrate towards attractive signals. In ''E.coli'' this is achieved through a signal transduction system that controls the phosphorylation state of the response regulator protein ''CheY''. In the absence CheY-P the flagellum rotates CWW in a "run" state. The presence of ''CheY-P'', induces a switch to CW rotation resulting in "tumbling" which randomly reorients the cell. When an attractant binds to a receptor it initiates a conformational change and downstream cascade that leads to suppression of CheA, a protein that normally phosphoryates''CheY'' to ''CheY-P''. The absence of ''CheY-P'' causes the flagellum to remain in the "run" state leading to migration towards the signal. A third protein, ''CheZ'' helps regulate the circuit by preventing the accumulation of ''CheY-P'' through dephosphorylation.	+	The rotation of the flagellum and the direction of movement is often regulated by sensory stimuli, allowing the cell to migrate towards attractive signals. In ''E.coli'' this is achieved through a signal transduction system that controls the phosphorylation state of the response regulator protein ''CheY''. In the absence CheY-P the flagellum rotates CWW in a "run" state. The presence of ''CheY-P'', induces a switch to CW rotation resulting in "tumbling" which randomly reorients the cell. When an attractant binds to a receptor it initiates a conformational change and downstream cascade that leads to suppression of CheA, a protein that normally phosphoryates ''CheY'' to ''CheY-P''. The absence of ''CheY-P'' causes the flagellum to remain in the "run" state leading to migration towards the signal. A third protein, ''CheZ'' helps regulate the circuit by preventing the accumulation of ''CheY-P'' through dephosphorylation.

	The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and used for food. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].		The 2009 Imperial College of London igem team attempted to engineer ''e.coli'' chemotaxis towards malate so that cells would migrate towards plant roots (which excrete malate). The ''e.coli'' cells could then be taken up by the plant and used for food. To do this they introduced a malate chemoreceptor from ''Pseudomonas aeruginosa'' and demonstrated that cells tended to be in the run state more often when exposed to malate [http://2011.igem.org/Team:Imperial_College_London/Project_Chemotaxis_Testing 2009 Team Auxin].

Erik Quandt at 15:32, 26 March 2012

Erik Quandt — Mon, 26 Mar 2012 15:32:12 GMT

←Older revision		Revision as of 15:32, 26 March 2012
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	===Focal Adhesion Model===		===Focal Adhesion Model===
	[[Image:gliding.jpg \|left\| thumb \| 150px \| Focal adhesions/motor complexes in ''Myxococcus xanthus''<cite>Zussman2011</cite>]]		[[Image:gliding.jpg \|left\| thumb \| 150px \| Focal adhesions/motor complexes in ''Myxococcus xanthus''<cite>Zussman2011</cite>]]
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	In this model, large focal adhesion complexes extend from the cell and connect the extracellular surface to actin-like cytoskeletal filaments. Motor proteins attached to the intracellular portion of the focal adhesion push backwards and move the focal adhesion along the cytoskeletal filament to move the cell forward.		In this model, large focal adhesion complexes extend from the cell and connect the extracellular surface to actin-like cytoskeletal filaments. Motor proteins attached to the intracellular portion of the focal adhesion push backwards and move the focal adhesion along the cytoskeletal filament to move the cell forward.
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	=References=		=References=