E. Montoya

Struvite production by Myxococcus coralloides D

Abstract Myxococcus coralloides D has been shown to produce extracellular crystals, which have been identified via scanning electron microscopy and X-ray diffraction to be struvite (MgHN4PO4·6H2O). This is the first occasion that the production of this mineral by a myxobacterium has been described.

Evidence for an activating substance related to autolysis in Myxococcus coralloides D

When cells of Myxococcus coralloides D grow as a suspension in liquid media the cultures enter a lysis phase after having reached a critical level of cell density. Supernatants of prelytic cells added to fresh cultures are able to induce autolysis quickly. If prelytic cells are transferred to supernatants of fresh cultures, autolysis is retarded; thus delay is also observed when prelytic cells are transferred to fresh medium at the same cellular density. In the sequence of events resulting in cell lysis an activating substance may be involved. This substance may be excreted into the medium. The substance seems to be stable at high temperatures, extreme pH values and enzymatic treatment.

Phosphatase activities in the life cycle of Myxococcus coralloides D

SUMMARY: The effect of phosphate on the different stages of the life cycle of Myxococcus coralloides D has been examined. A high concentration of phosphate inhibited the process of fructification, but glycerol-induced myxospore formation and germination were independent of phosphate concentration. Acid and alkaline phosphatases were detected and both were released into liquid medium during the exponential growth phase. On solid medium, phosphatase activities showed different patterns according to the stage of the life cycle. The increase of these two activities was transient during glycerol-induced myxospore formation. Differences in phosphatase activities during germination of glycerol-induced myxospores and fruiting-body myxospores were found.

Polyphosphate glucokinase and ATP glucokinase activities in Mycococcus coralloides D

Polyphosphate glucokinase and ATP glucokinase were detected in cell-free extracts of Myxococcus coralloides strain D, but pyrophosphate glucokinase was not detected. Both glucokinase activities were separated by chromatography. The approximate molecular weight is 61 000 for polyphosphate glucokinase and 47 000 for ATP glucokinase. Substrate specificity and pH optimum was studied in the polyphosphate glucokinase. Polyphosphate and ATP glucokinase activities were verified by 13C Nuclear Magnetic Resonance.

Effect of phosphate on antibiotic and extracellular protein production by Myxococcus coralloides D

SummaryThe effect of inorganic phosphate concentrations on antibiotic and extracellular protein production by Myxococcus coralloides D have been examined. Antibiotic production by growing cells of this myxobacterium was maximal at phosphate concentrations of 10–20 mM, but was inhibited by concentrations higher than 20 mM. The total extracellular protein and the extracellular protein per cell ratio were independent of phosphate levels in the culture broth.

Production of acid and alkaline phosphatases by Myxococcus coralloides.

Acid and alkaline phosphatase ofMyxococcus coralloides were examined during vegetative growth in a liquid medium. Two extracellular phosphatases and two cell-bound phosphatases, acid and alkaline in both cases, were produced. The phosphatase production was unaltered by the presence of high concentrations of inorganic phosphate. Both enzymes were produced constitutively. These two hydrolases were released into the growth medium during the exponential growth phase (approximately 10% of total activity). The production of these enzymes was modified by the presence of organic acids and metal ions in the medium.