RESOLVING THE HIGH-RESOLUTION ARCHITECTURE, ASSEMBLY AND FUNCTIONAL REPERTOIRE OF BACTERIAL SYSTEMS BY IN VITRO ATOMIC FORCE MICROSCOPY - Life at the Nanoscale: Atomic Force Microscopy of Live Cells - page 88

germinating
spores appears to be similar. Thus, at later stages of the germination process,
the

The structural dynamics of C. novyi-NT 8 and B. atrophaeus

spore coat layers seen in Fig. 4.11 , which are exposed at early
stages of germination, start to dissolve. Thus, this process was initiated by
the formation of issures ( Fig. 4.11a ) , which subsequently widened and
elongated ( Fig. 4.11b-e ) , resulting in isolated islands of remnant coat layers
( Fig. 4.11e,f ) .

C. novyi-NT

(a) (b) (c)

(d) (e) (f)

Figure 4.11. Dynamic AFM height imaging of degrading C. novyi-NT spore coat
layers. Fissures irst appeared (a,b), then laterally expanded into wide gaps (c-e) and
eventually resulted in the removal of whole layers, exposing the underlying layer (e,f,
arrows in (e)). One expanding issure is indicated with a white oval in (a-f ). Time in
germination medium in hr:min was 0:45 (a), 0:50 (b), 0:55 (c), 1:00 (d), 1:05 (e), 1:10
(f ). Images reproduced, with permission from Ref. 8. © (2007) American Society for
Microbiology.

Similarly to B. atrophaeus spore germination mechanisms described

earlier, coat degradation likely occurs under the inluence of germination-

activated lytic enzymes. In fact, such lytic enzymes are known to be encoded
within the spores contain

mRNA, and these mRNA molecules are enriched in proteins that could assist
with cortex and other degradation. 58
At the inal stages of germination, the coat layers dissolved completely
( Fig. 4.12a ) , fully exposing the ~20-25 nm thick undercoat layer. In the
following stage of germination, this layer also disintegrated. This proceeded

C. novyi-NT genome. 58 Interestingly, C. novyi-NT