Elastic and inelastic light scattering from single bacterial spores in an optical trap allows the monitoring of spore germination dynamics.
Raman scattering spectroscopy and elastic light scattering intensity (ESLI) were used to simultaneously measure levels of Ca-dipicolinic acid (CaDPA) and changes in spore morphology and refractive index during germination of individual Bacillus subtilis spores with and without the two redundant enzymes (CLEs), CwlJ and SleB, that degrade spores' peptidoglycan cortexes. Conclusions from these measurements include (1) CaDPA release from individual wild-type germinating spores was biphasic; in a first heterogeneous slow phase, T(lag), CaDPA levels decreased approximately 15%, and in the second phase ending at T(release), remaining CaDPA was released rapidly; (2) in L-alanine germination of wild-type spores and spores lacking SleB (a) the ESLI rose approximately 2-fold shortly before T(lag) at T(1), (b) following T(lag), the ESLI again rose approximately 2-fold at T(2) when CaDPA levels had decreased approximately 50%, and (c) the ESLI reached its maximum value at approximately T(release) and then decreased; (3) in CaDPA germination of wild-type spores, (a) T(lag) increased and the first increase in ESLI occurred well before T(lag), consistent with different pathways for CaDPA and L-alanine germination, (b) at T(release), the ESLI again reached its maximum value; (4) in L-alanine germination of spores lacking both CLEs and unable to degrade their cortex, the time DeltaT(release) (T(release) - T(lag)) for excretion of > or = 75% of CaDPA was approximately 15-fold higher than that for wild-type or sleB spores; and (5) spores lacking only CwlJ exhibited a similar but not identical ESLI pattern during L-alanine germination to that seen with cwlJ sleB spores and the high value for DeltaT(release).
Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, USA.
Lixin
L
Peng
De
D
Chen
Peter
P
Setlow
Yong-qing
YQ
Li
D000409:Alanine / Q000378:metabolism; D000581:Amidohydrolases / Q000378:metabolism; D001412:Bacillus subtilis / Q000254:growth & development* / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D006867:Hydrolases / Q000378:metabolism; D010848:Picolinic Acids / Q000032:analysis; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013171:Spores, Bacterial / Q000254:growth & development* / Q000378:metabolism
D001426:Bacterial Proteins; D010848:Picolinic Acids; C101656:SleB protein, Bacillus; C433796:CwlJ protein, Bacillus subtilis; D006867:Hydrolases; D000581:Amidohydrolases; D000409:Alanine; C004860:dipicolinic acid