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Are Myxobacteria intelligent?

Kaiser D - Front Microbiol (2013)

Bottom Line: Both swarming-growth and starvation-induced fruiting body development depend upon the specificity and effectiveness of signals passed between cells.After separating, both cells move on to make similar, transient connections with other cells.Eventually, the signal spreads across a prescribed population of communicating cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Stanford University School of Medicine Stanford, CA, USA.

ABSTRACT
"Intelligence" is understood in different ways. Because humans are proud of their ability to speak, intelligence often includes the ability to communicate with others, to plan for the future, and to solve frequently encountered problems. Myxobacteria are among the most socially adept and ubiquitous of bacteria that live in the soil. To survive in nature, Myxobacteria communicate with their peers, using signals that elicit specific responses. Both swarming-growth and starvation-induced fruiting body development depend upon the specificity and effectiveness of signals passed between cells. Dynamic swarms spread outward, forming regular multi-cellular and multi-layered structures as they spread. Several different extra-cellular signals have been identified for fruiting body development and one is hypothesized for swarm development. Some extra-cellular signals are small, diffusible molecules. Others are protein molecules. The swarm signal appears to consist of structurally complex, protein to protein, contact junctions between pairs of side by side aligned cells. Each junction persists for less than a minute before disconnecting. After separating, both cells move on to make similar, transient connections with other cells. Eventually, the signal spreads across a prescribed population of communicating cells.

No MeSH data available.


Related in: MedlinePlus

The path followed by the signal postulated to synchronize the pacemakers of the cell pair shown. Arrows point toward the next pair of numbered A-motility proteins to bind together. Adhesion proteins are represented in the figure by numbers that indicate their position in the sequence of pairwise binding steps, unless their location is established, like CglB and FrzCD. 1" 2 is the first pair of proteins to bind, 2" 3 is the second pair, n" n + 1 is the next to last pair, and n + 1" FrzCD is the last pair. FrzCD is a methylated, regulatory protein, not an A-motility protein. The two cells shown are joined for a short time, just long enough to complete the whole series of binding steps that run from CglB to FrzCD, and through all the membrane bound compartments of the cell. PP, in the diagram, represents the cell’s periplasmic compartment.
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Figure 2: The path followed by the signal postulated to synchronize the pacemakers of the cell pair shown. Arrows point toward the next pair of numbered A-motility proteins to bind together. Adhesion proteins are represented in the figure by numbers that indicate their position in the sequence of pairwise binding steps, unless their location is established, like CglB and FrzCD. 1" 2 is the first pair of proteins to bind, 2" 3 is the second pair, n" n + 1 is the next to last pair, and n + 1" FrzCD is the last pair. FrzCD is a methylated, regulatory protein, not an A-motility protein. The two cells shown are joined for a short time, just long enough to complete the whole series of binding steps that run from CglB to FrzCD, and through all the membrane bound compartments of the cell. PP, in the diagram, represents the cell’s periplasmic compartment.

Mentions: In the fore-mentioned group of exposed and organized proteins, CglB, CglC, CglD, CglE, and CglF are proposed to link a pair of adjacent cells together in a particular way – to link them through a pair of multi-protein structures known as focal adhesions (Mignot et al., 2005, 2007) and to link them, thus, for less than a minute before the two cells separate and move on to link similarly to other cells, and signal to them. The focal adhesions are found on the sides of M. xanthus cells; each adhesion can be seen as a discrete series of fluorescent foci. Despite the multitude of different proteins that cluster in the focal adhesions, no amino acid sequences related to microtubule-based kinesin motors or actin-based myosin motors (Vale and Milligan, 2000) have been identified (see Luciano et al., 2011, for example). Indeed, the 15 or more A-motility proteins in the clusters associated with focal adhesions seem well-suited for a signaling pathway for two reasons. One, many of the proteins can bind one another in specific pairs as measured by GST affinity chromatography, identified in Table 1 of Nan et al. (2010). Two, different binding proteins are found to favor localization in different subcellular compartments of an M. xanthus cell. Proceeding inward, they are found on the outer surface of the outer membrane, in the periplasmic space, on the outer surface of the peptidoglycan sacculus, associated with the inner membrane, and finally in the cytoplasm, where the pacemaker proteins are located (Kaiser and Warrick, 2011). Due to their broad spatial distribution, the hypothetical signal would be capable of linking methylated-FrzCD in the pacemaker of one cell through pairs of protein 1 transiently bound to protein 2 links to CglB – one of the 15 A-motility proteins found in a focal adhesion – on the surface of that cell. CglB etc. on the surface of the first cell could assemble together with CglB etc. on the surface of the second cell, transiently forming a junction with a specific structure between the 2 cells. From that junction, the signal would link through the same series of protein 1" protein 2 pairs until it reached FrzCD in the pacemaker of the second cell. When completed, as shown in Figure 2, the series of signal links could plausibly bring the pacemakers of both cells to the same phase of their oscillatory cycles. The circuit of Figure 2 offers a concrete and thus testable example of the signaling alternative.


Are Myxobacteria intelligent?

Kaiser D - Front Microbiol (2013)

The path followed by the signal postulated to synchronize the pacemakers of the cell pair shown. Arrows point toward the next pair of numbered A-motility proteins to bind together. Adhesion proteins are represented in the figure by numbers that indicate their position in the sequence of pairwise binding steps, unless their location is established, like CglB and FrzCD. 1" 2 is the first pair of proteins to bind, 2" 3 is the second pair, n" n + 1 is the next to last pair, and n + 1" FrzCD is the last pair. FrzCD is a methylated, regulatory protein, not an A-motility protein. The two cells shown are joined for a short time, just long enough to complete the whole series of binding steps that run from CglB to FrzCD, and through all the membrane bound compartments of the cell. PP, in the diagram, represents the cell’s periplasmic compartment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824092&req=5

Figure 2: The path followed by the signal postulated to synchronize the pacemakers of the cell pair shown. Arrows point toward the next pair of numbered A-motility proteins to bind together. Adhesion proteins are represented in the figure by numbers that indicate their position in the sequence of pairwise binding steps, unless their location is established, like CglB and FrzCD. 1" 2 is the first pair of proteins to bind, 2" 3 is the second pair, n" n + 1 is the next to last pair, and n + 1" FrzCD is the last pair. FrzCD is a methylated, regulatory protein, not an A-motility protein. The two cells shown are joined for a short time, just long enough to complete the whole series of binding steps that run from CglB to FrzCD, and through all the membrane bound compartments of the cell. PP, in the diagram, represents the cell’s periplasmic compartment.
Mentions: In the fore-mentioned group of exposed and organized proteins, CglB, CglC, CglD, CglE, and CglF are proposed to link a pair of adjacent cells together in a particular way – to link them through a pair of multi-protein structures known as focal adhesions (Mignot et al., 2005, 2007) and to link them, thus, for less than a minute before the two cells separate and move on to link similarly to other cells, and signal to them. The focal adhesions are found on the sides of M. xanthus cells; each adhesion can be seen as a discrete series of fluorescent foci. Despite the multitude of different proteins that cluster in the focal adhesions, no amino acid sequences related to microtubule-based kinesin motors or actin-based myosin motors (Vale and Milligan, 2000) have been identified (see Luciano et al., 2011, for example). Indeed, the 15 or more A-motility proteins in the clusters associated with focal adhesions seem well-suited for a signaling pathway for two reasons. One, many of the proteins can bind one another in specific pairs as measured by GST affinity chromatography, identified in Table 1 of Nan et al. (2010). Two, different binding proteins are found to favor localization in different subcellular compartments of an M. xanthus cell. Proceeding inward, they are found on the outer surface of the outer membrane, in the periplasmic space, on the outer surface of the peptidoglycan sacculus, associated with the inner membrane, and finally in the cytoplasm, where the pacemaker proteins are located (Kaiser and Warrick, 2011). Due to their broad spatial distribution, the hypothetical signal would be capable of linking methylated-FrzCD in the pacemaker of one cell through pairs of protein 1 transiently bound to protein 2 links to CglB – one of the 15 A-motility proteins found in a focal adhesion – on the surface of that cell. CglB etc. on the surface of the first cell could assemble together with CglB etc. on the surface of the second cell, transiently forming a junction with a specific structure between the 2 cells. From that junction, the signal would link through the same series of protein 1" protein 2 pairs until it reached FrzCD in the pacemaker of the second cell. When completed, as shown in Figure 2, the series of signal links could plausibly bring the pacemakers of both cells to the same phase of their oscillatory cycles. The circuit of Figure 2 offers a concrete and thus testable example of the signaling alternative.

Bottom Line: Both swarming-growth and starvation-induced fruiting body development depend upon the specificity and effectiveness of signals passed between cells.After separating, both cells move on to make similar, transient connections with other cells.Eventually, the signal spreads across a prescribed population of communicating cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Stanford University School of Medicine Stanford, CA, USA.

ABSTRACT
"Intelligence" is understood in different ways. Because humans are proud of their ability to speak, intelligence often includes the ability to communicate with others, to plan for the future, and to solve frequently encountered problems. Myxobacteria are among the most socially adept and ubiquitous of bacteria that live in the soil. To survive in nature, Myxobacteria communicate with their peers, using signals that elicit specific responses. Both swarming-growth and starvation-induced fruiting body development depend upon the specificity and effectiveness of signals passed between cells. Dynamic swarms spread outward, forming regular multi-cellular and multi-layered structures as they spread. Several different extra-cellular signals have been identified for fruiting body development and one is hypothesized for swarm development. Some extra-cellular signals are small, diffusible molecules. Others are protein molecules. The swarm signal appears to consist of structurally complex, protein to protein, contact junctions between pairs of side by side aligned cells. Each junction persists for less than a minute before disconnecting. After separating, both cells move on to make similar, transient connections with other cells. Eventually, the signal spreads across a prescribed population of communicating cells.

No MeSH data available.


Related in: MedlinePlus