Loshon Charles A, Wahome Paul G, Maciejewski Mark W, Setlow Peter
Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
J Bacteriol. 2006 Apr;188(8):3153-8. doi: 10.1128/JB.188.8.3153-3158.2006.
Bacteria of various Bacillus species are able to grow in media with very high osmotic strength in part due to the accumulation of low-molecular-weight osmolytes such as glycine betaine (GB). Cells of Bacillus species grown in rich and minimal media contained low levels of GB, but GB levels were 4- to 60-fold higher in cells grown in media with high salt. GB levels in Bacillus subtilis cells grown in minimal medium were increased approximately 7-fold by GB in the medium and 60-fold by GB plus high salt. GB was present in spores of Bacillus species prepared in media with or without high salt but at lower levels than in comparable growing cells. With spores prepared in media with high salt, GB levels were highest in B. subtilis spores and > or =20-fold lower in B. cereus and B. megaterium spores. Although GB levels in B. subtilis spores were elevated 15- to 30-fold by GB plus high salt in sporulation media, GB levels did not affect spore resistance. GB levels were similar in wild-type B. subtilis spores and spores that lacked major small, acid-soluble spore proteins but were much lower in spores that lacked dipicolinic acid.
多种芽孢杆菌属细菌能够在具有非常高渗透压的培养基中生长，部分原因是积累了低分子量的渗透保护剂，如甘氨酸甜菜碱（GB）。在丰富培养基和基本培养基中生长的芽孢杆菌属细胞含有低水平的GB，但在高盐培养基中生长的细胞中GB水平要高4至60倍。在基本培养基中生长的枯草芽孢杆菌细胞中的GB水平，因培养基中的GB而增加约7倍，因GB加高盐而增加60倍。GB存在于在有或没有高盐的培养基中制备的芽孢杆菌属孢子中，但水平低于可比的生长细胞。对于在高盐培养基中制备的孢子而言，GB水平在枯草芽孢杆菌孢子中最高，在蜡样芽孢杆菌和巨大芽孢杆菌孢子中低20倍或更多。尽管在芽孢形成培养基中GB加高盐使枯草芽孢杆菌孢子中的GB水平提高了15至30倍，但GB水平并不影响孢子抗性。野生型枯草芽孢杆菌孢子和缺乏主要小的、酸溶性孢子蛋白的孢子中的GB水平相似，但在缺乏吡啶二羧酸的孢子中要低得多。
