矿物微尘对人体肠道大肠杆菌和嗜酸乳杆菌的体外作用研究

On the interactive effects in vitro between mineral dust and the representative human intestinal bacteria

研究了采集自居住环境的矿物微尘对人体肠道菌群主要代表性菌株大肠杆菌（Escherichia coli）和嗜酸乳杆菌（Lactobacillus acidophilus）的体外作用。测定了矿物微尘对培养基pH值的影响,微尘与菌体共同作用后培养基pH值的变化,并用活菌计数法检测了矿物微尘对大肠杆菌和嗜酸乳杆菌生长的影响。结果表明微尘对大肠杆菌的生长起抑制作用。培养基中矿物微尘质量分数达3%时即对大肠杆菌生长有显著抑制作用,微尘质量分数达20%时,大肠杆菌生长受到完全抑制。微尘质量分数在3%-20%这一较宽幅度内,大肠杆菌虽受抑制但能生长,说明大肠杆菌耐受矿物微尘影响的能力较强。矿物微尘对嗜酸乳杆菌生长影响复杂,培养基中矿物微尘质量分数低时起促进作用,质量分数较高时起抑制作用。微尘质量分数达5%时,嗜酸乳杆菌生长即受到完全抑制。嗜酸乳杆菌耐受矿物微尘影响的能力较弱,远小于大肠杆菌。结果还表明矿物微尘影响大肠杆菌与嗜酸乳杆菌生长的主要因素是微尘本身的化学成分与物理性质,微尘的碱性因素对大肠杆菌和嗜酸乳杆菌有一定影响,但不是主要影响因素。

The present thesis is to introduce its authors＇ study find ings on the interactive effects in vitro between mineral dust and the representative human intestinal bacteria. The mineral dust sample was collected from the authentic living environment of Qingyi town, Sichuan, China. First of all, we have analyzed the interaction in vitro between mineral dust and major representative human intestinal bacteria, including Escherichia cell and Lactobacillus acidophilus. The influence of the mineral dust on the medium has been deter＇ted with the change of the medium pH after the cooperation of mineral dust and bacterium cells. Next, we have determined the cell number by viable count method so as to define the effect of the miner dust on the growth of Escherichia cell and Lactobacillus acidophilus. The re suits of our study prove that the mineral dust inhibites the growth of Escherichia coll. Such effect is likely to be significant when its concentration reached 3%. But, when the concentration of the mineral dust reached 20%, no growth of Escherichia cell would happen, This may account for the strong tolerance of Escherichia colt to the mineral dust. Otherwise the effect of the mineral dust on Lactobacillus acidophilu would be complicated. In addition, it also implies that the mineral dust can be expected to promote the growth of Lactobacillus acidophilus when its concentration is lower. However, the growth would be inhibited when the concentration becomes higher, For example, when it was 5 % , Lactobacillus acidophilus would not be able to grow. Besides, it can also be found that the tolerance of Escherichia cell to mineral dust is higher than that of Lactobacillus acidophilus. Though the alky factor of the mineral dust may effect the growth of Escherichia cell and Lactobacillus acidophilus, it proves not to be the main influencing factor. Thus, it can be coueluded that the inhibiting concentration and lethal concentration of mineral dust here found may provide a scientific starting points for environment protection arid urban atmosphere pollution monitoring. Furthermore, the results also show that it was not the alky factor but the chemical composition and physical property of the mineral dust which mainly affect the growth of Escherichia cell and Lactobacillus acidophilus.