Polarized relationship of bacterial spore loci to the "old" and "new" ends of sporangia

Abstract

The frequency of association of spore loci with the "old" and "new" ends of rod-shaped sporangia in batch cultures of Bacillus megaterium ATCC 19213 was estimated by phase contrast microscopy. The analysis was facilitated by (i) the association of most of the sporangia into chains of two to five sporangia and (ii) the occurrence of two types of cross wall distinguishable by their degree of splitting. It was concluded that a newly formed spore is located at the "old" end of a sporangium. By inference, the sporulation division septum locus is distal to the ultimate normal cell division septum, i.e., proximal to the "old" pole of the B. megaterium sporangium. This result is discussed in relation to deoxyribonucleic acid segregation during sporulation.

Spore location patterns in sporulating doublets of Bacillus cereus and Bacillus megaterium, derived from single doublet isolates with differing sporulation geometry

“…The results for B. megaterium are consistent with those previously published (3,8), but show that formation of spores at the new ends of the cells does occur at a low frequency, which cannot be explained by asynchronous division of cells during filament formation (8). The results also agree with a report of a higher frequency of formation of spores at the new ends of the sporangia in B. cereus than in B. megaterium (4).…”

“…Previous studies on spore location patterns in Bacillus megaterium (2,3,7,8) have shown that the majority of spores are formed distally to the previous division septum, i.e., at the old ends of the sporangia. In those studies, the sporulating cells were not formed from spores arising only from the new or the old end of the sporangium, but presumably from a mixed population of spores formed at both the new and old ends of the sporangia.…”

Patterns of spore locations in pairs of Bacillus cereus sporangia

“…Sporangia of the bacterium were produced in the various media listed in Table 1. Spore locations in over 2,000 pairs of sporangia were observed by phasecontrast microscopy as described previously (7). As expected from their polar developmental sites in B. cereus sporangia (5), the spores were generally located terminally or subterminally (Fig.…”

Cell Polarity in Bacillus subtilis: Statistical Analysis of Factors Influencing the Positions of Spores in Sister Sporangia

“…It is easy to determine by phase-contrast microscopy whether a spore has been formed at the 'old' (distal to the newest division septum) or 'new' (proximal to the newest division septum) end of a sporangium (Hitchins, 1975). The possible patterns of spore positions in sister sporangia are as follows (assuming that all sporangia contain phase-bright spores) :…”