对氨基苯甲酸对乳杆菌生长影响的体外实验

目的:探讨对氨基苯甲酸菌株(PABA)对牙本质龋、根面龋致病菌之一的乳杆菌生长的影响。方法:10倍系列稀释法配制浓度为10-3~10-10gPL的PABA液,将其分别加入改良的Carlsson培养基中,再将乳杆菌ATCC4356放入该培养基厌氧培养48 h(80%N2、10%H2、10%CO2),用紫外可见分光光度仪测定细菌浓度OD值(K=540 nm);并在琼脂平板培养观察细菌生长的情况,进行菌落计数。结果:PABA也有促进乳杆菌生长的能力,当PABA的浓度从 10-10~10-4gPL增加时,其促进乳杆菌生长的能力增强(P<0.05),且当浓度为10-5gPL时,促进乳杆菌生长的能力达最强,随着PABA的浓度增加到10-4gPL时,此促进作用开始下降,PABA的浓度再增加至10-3gPL时,对乳杆菌的生长无明显的促进作用。结论:PABA的浓度为10-5gPL时,促进乳杆菌生长的能力达最强,高于或低于此浓度,这种促生长的作用均下降。

Effects of Para-aminobenzoic Acid (PABA) on Growth of Lactobacillus acidophilus

OBJECTIVE: The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth of Lactobacillus acidophilus (L. acidophilus). METHODS: Different concentrations of PABA (10(-10)-10(-3) g/L) were separately transferred to the modified Carlsson medium. L. acidophilus (ATCC4356) grew in these Carlsson media. All cultures were incubated at 37 degrees C anaerobically in atmosphere of 80% of nitrogen, 10% of hydrogen, and 10% of carbon dioxide for 48 hours. Absorbance values (lambda = 540 nm) of bacterial suspensions were measured using a spectrometer (UV-1601). Colony forming units (CFU) were obtained by growing L. acidophilus in Carlsson media with different concentration of PABA (10(-10)-10(-3) g/L). RESULTS: Different concentrations of PABA (10(-10)-10(-4) g/L) had different stimulating effects on the growth of L. acidophilus (P < 0.05). But stimulating effects declined, when PABA concentration was 10(-5) g/L, and when the concentration of PABA reached 10(-3) g/L, the stimulating effect disappeared. CONCLUSION: This study indicates PABA stimulates the growth of L. acidophilus, and PABA can promote growth of L. acidophilus.