UV RESONANCE RAMAN-SPECTRA OF BACILLUS SPORES
UV RESONANCE RAMAN-SPECTRA OF BACILLUS SPORES
复制标题
DOI：
10.1366/0003702924125609
复制
发表时间：
1992-02-01
影响因子：
3.5
通讯作者：
SPERRY, JF
中科院分区：
文献类型：
--
作者：
GHIAMATI, E;MANOHARAN, R;SPERRY, JF
研究了蜡样芽孢杆菌、巨芽孢杆菌和枯草芽孢杆菌内生孢子在222.7、230.7、242.5和251.1 nm处的紫外共振拉曼光谱，并与营养细胞的光谱进行了比较。测定了二吡啶酸和二吡啶酸钙水溶液在相同波长下的共振拉曼光谱。在222、231和251 nm激发下，内生孢子及其相应的萌发孢子的光谱只有轻微的差异。然而，当激发发生在242 nm时，会出现非常显著的差异。在242 nm处，蜡样芽孢杆菌萌发孢子的光谱与内生孢子的光谱相减，得到的差谱几乎完全由二吡啶酸盐产生。营养细胞和内生孢子在所有激发波长上都表现出很大的光谱差异。这些光谱差异随着激发波长的变化而剧烈变化，似乎是蛋白质和核酸，特别是核糖体RNA的数量和组成的巨大差异的结果。从纯二吡啶酸、二吡啶酸钠和二吡啶酸钙盐的水溶液以及在各种激发波长下的孢子中获得了非常显著的拉曼光谱共振增强。然而，只有在242 nm的激发下，孢子中的双吡啶酸盐光谱才有明显的增强。因此，只有在242nm光下才有可能选择性和敏感地激发和研究孢子中的二吡啶酸钙。在242nm激发下，二吡啶酸酯光谱的共振增强主要是由于与吡啶环和/或羧酸基相关的n-pi*电子跃迁的共振相互作用。
UV resonance Raman spectra of Bacillus cereus, Bacillus megaterium, and Bacillus subtilis endospores have been excited at 222.7, 230.7, 242.5, and 251.1 nm, and spectra have been compared with those of vegetative cells. The resonance Raman spectra of aqueous solutions of dipicolinic acid and calcium dipicolinate have been measured at the same wavelengths. Spectra of endospores and their corresponding germinated spores show only modest differences when excited at 222, 231, and 251 nm. However, very substantial differences appear when excitation occurs at 242 nm. Difference spectra obtained at 242 nm by subtracting spectra of germinated spores of Bacillus cereus from spectra of their corresponding endospores are attributed almost entirely to dipicolinate. Vegetative cells and endospores show large spectral dissimilarities at all exciting wavelengths. These spectral differences, which vary strongly with exciting wavelength, appear to be the result of large differences in the amounts and composition of proteins and nucleic acids, especially ribosomal RNA. The very substantial resonance enhancement of Raman spectra has been obtained from aqueous solutions of pure dipicolinic acid and of sodium and calcium dipicolinate salts, as well as spores at the various exciting wavelengths. The strong enhancement of dipicolinate spectra in spores, however, was noted only with 242-nm excitation. Consequently, only with 242-nm light was it possible to selectively and sensitively excite and study calcium dipicolinate in spores. Resonance enhancement of the dipicolinate spectra with 242-nm excitation appears due primarily to resonance interactions with n-pi* electronic transitions associated with the pyridine ring and/or the carboxylate group.