液相中炭疽杆菌形貌的原子力显微镜观测

Morphological observation on Bacillus anthracis by using atomic force microscopy in fluid tapping mode

目的利用原子力显微镜液相模式观测炭疽杆菌形态,获得液相中炭疽杆菌芽胞和繁殖体对于溶菌酶的形态学抗性变化数据。方法应用原子力显微镜液相模式观察炭疽杆菌繁殖体及芽胞的超微结构,并对其主要指标进行测量比较。结果1×PBS溶液中的炭疽杆菌繁殖体,菌体杆状,竹节样排列,菌体间连接致密,长度为2,757.30±1227.086nm,宽度为1,710.90±226.10nm,Rq为15.447±3.418nm,Ra为13.239±2.733nm;炭疽杆菌芽胞椭圆形,多散在分布,表面平滑,长度为2,014.00±227.155nm,宽度为1,264.10±132.180nm,Rq为22.803±5.660nm,Ra为18.010±4.568nm。0.01 mg/mL溶菌酶溶液中的炭疽杆菌繁殖体形态不规则,表面凹凸起伏,边缘粗糙,有囊状突起,长度为2,836.00±1025.137nm,宽度为2,449.00±212.78nm,Rq为17.068±4.427nm,Ra为14.776±3.746nm;0.01 mg/mL溶菌酶溶液中的炭疽杆菌芽胞,形态规则,边缘平滑,未见凹凸起伏和囊状突起,而1 mg/mL溶菌酶溶液环境中的炭疽杆菌芽胞形态不规则,表面起伏,变化较大,其长度为2,155.00±202.663nm,宽度为1,344.00±162.631nm,Rq为24.849±3.427nm,Ra为20.869±2.550nm。结论通过原子力显微镜液相模式下的观察和测量,清楚地显示了溶液中炭疽杆菌的微观形貌及其变化,0.01 mg/mL的溶菌酶就能使炭疽杆菌繁殖体发生形态学变化,而炭疽杆菌芽胞形貌发生变化则需要1 mg/mL的高浓度溶菌酶的作用。

The atomic force microscopy in liquid tapping mode was used to examine the ultrastruretures of vegetative forms and spores of Bacillus anthracis in liquid condition and to obtain the data on their change of morphological resistance to lysozyme. We found that the microstructures of B. anthracis vegetative form and spore were imaged in a series of diluted lysozyme solutions in order to observe the morpbologic changes of bacteria. B. anthracis displayed different structures in 1 ×PBS solution, 0.01 mg/mL lysozyme solution and 1 mg/mL lysozyme solution. The length, width, Rq and Ra of the vegetative form of B. anthracis were 2 757.30±1 227. 086 nm, 1 710.90±226.10 nm, 15. 447±3. 418 nm and 13. 239±2. 733 nm respectively; while those of the oval , dispersed and smooth spores of B. anthracis were 2014.00 ± 227. 155 nm. 1 264.10 ± 132--180 nm, 22. 803±5. 660 nm and 18. 010±4. 568 nm respectively. The morphology of vegetative forms in 0. 01 mg/mL of lysozyme solution appeared to be irregular on the surface and rough in the surrounding with cystic projections. Under this condi- tion, their length, width, Rq and Ra became to be 2836.00±1025. 137 nm. 2446.00±212.78 nm, 17. 068±4. 427 nm and 14. 776±3. 746 nm respectively; while those in lmg/mL of lysozyme solution were 3329.00±453. 761 nm, 2469.00±246.46 nm. 18. 034±3. 193 nm and15. 194±2,530 respectively and the morphology of their spores appeared to be irregular with surface projection and variable morphological changes. It is evident that the fluid tapping mode technique of atomic force microscopy can provide as a rapid and useful toot for the study on B. anthracis in liquid phase and has potential to be used as a method for screening of the pathogenic microorganisms.