Peng Lixin, Chen De, Setlow Peter, Li Yong-qing
Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, USA.
Anal Chem. 2009 May 15;81(10):4035-42. doi: 10.1021/ac900250x.
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).
拉曼散射光谱和弹性光散射强度(ESLI)被用于同时测量枯草芽孢杆菌单个孢子在有和没有两种冗余酶(CwlJ和SleB,它们可降解孢子的肽聚糖皮层)的情况下萌发过程中吡啶二羧酸钙(CaDPA)的水平以及孢子形态和折射率的变化。这些测量得出的结论包括:(1)单个野生型萌发孢子中CaDPA的释放是双相的;在第一个异质缓慢阶段T(lag),CaDPA水平下降约15%,在第二个阶段于T(release)结束时,剩余的CaDPA迅速释放;(2)在野生型孢子和缺乏SleB的孢子的L-丙氨酸萌发过程中,(a)在T(lag)之前的T(1)时刻,ESLI大约上升2倍,(b)在T(lag)之后,当CaDPA水平下降约50%时,ESLI在T(2)时刻再次大约上升2倍,并且(c)ESLI在大约T(release)时达到最大值然后下降;(3)在野生型孢子的CaDPA萌发过程中,(a)T(lag)增加,并且ESLI的首次增加发生在T(lag)之前很久,这与CaDPA和L-丙氨酸萌发的不同途径一致,(b)在T(release)时,ESLI再次达到最大值;(4)在缺乏两种冗余酶且无法降解其皮层的孢子的L-丙氨酸萌发过程中,排泄≥75% CaDPA的时间DeltaT(release)(T(release) - T(lag))比野生型或sleB孢子高约15倍;(5)仅缺乏CwlJ的孢子在L-丙氨酸萌发过程中表现出与cwlJ sleB孢子类似但不完全相同的ESLI模式以及较高的DeltaT(release)值。