Extruding slime

Fontes and Kaiser [33] described a special case of tactic behavior in M. xanthus. They showed that the cells respond to stress in the agar. This response (elasticotaxis) depends on A-, but not on S-motility. According to Wolgemuth et al. [131], elasticotaxis arises from the tendency of the polyelectrolyte chains of extruding slime to align with polymer chains in the agar. 

Soda Ash Roasting. Some of the first processes to recover selenium on a commercial basis were based on roasting of copper slimes with soda ash to convert both selenium and tellurium to the +6 oxidation state. Figure 1 shows flow sheets for two such processes. Slimes are intensively mixed with sodium carbonate, a binder such as bentonite, and water to form a stiff paste. The paste is extruded or pelletized and allowed to dry. Care in the preparation of the extrudates or pellets is required to ensure that they have sufficient porosity to allow adequate access to the air required for oxidation. 

According to a model proposed by Wolgemuth et al. [131], the propulsive force is generated by hydration of polyelectrolyte slime in the nozzle. The slime is hydrated and consequently swells. The swollen polymer is extruded through the narrow opening of the nozzle pushing against the substratum. 

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