抗生素处理对坛紫菜叶状体生长和藻际微生物的影响

设计了氨苄青霉素、硫酸庆大霉素和卡那霉素3种抗生素的不同组合处理坛紫菜叶状体,旨在筛选出坛紫菜叶状体藻际微生物的最优去除方法;同时,探究紫菜叶状体生长与微生物群落变化之间的关系。结果显示,低浓度(10μg/mL)的硫酸庆大霉素或高浓度(800μg/mL)的卡那霉素处理,对坛紫菜叶状体生长均具一定的抑制作用,而不同浓度的氨苄青霉素处理均促进了叶状体生长。500μg/mL的氨苄青霉素、500μg/mL的硫酸庆大霉素与300μg/mL的卡那霉素3种抗生素混合处理叶状体24 h,不会抑制叶状体的生长;同时,对藻际微生物有较强的抑制性。不同的坛紫菜品系,不同的叶状体日龄和培养密度,以及在不同的海水盐度和不同浓度的营养盐中培养,抗生素处理组圆盘体的生长均比对照组快。通过比较抗生素处理组与对照组分离的菌株后发现,抗生素处理组有两株菌落形态和菌株形态与对照组显著不同的特有菌株。研究表明,在坛紫菜叶状体的生长过程中,某些对叶状体生长起阻碍作用的细菌如果大量繁殖,会抑制对叶状体生长有益的细菌繁殖,当用抗生素抑制了阻碍生长的细菌,就会使益生菌成为优势菌,促进叶状体的生长,益生菌对上述抗生素的处理不太敏感,但由于培养条件的改变,抗生素对阻碍生长的细菌的抑制作用会减弱,使得它们大量繁殖,从而抑制叶状体的生长。

The effects of antibiotics on growth and phycosphere microorganisms of Pyropia haitanensis thallus

In order to select the best method to remove microorganism of Pyropia haitanensis,we treated P.haitanensis thallus with different combinations of ampicillin,gentamicin sulfate and kanamycin.Meanwhile,we explored the relationship between the growth of P.haitanensis thallus and the change of microflora.The results showed that low concentration of gentamicin sulfate (10 μg/mL) or high concentration of kanamycin (800 μg/mL)could inhibit the growth ofP.haitanensis thallus.In contrast,ampicillin of each concentration in this paper had a promoting effect on the growth ofP.haitanensis thallus.We chose the combination of ampicillin (500 μg/mL),gentamicin sulfate (500 μg/mL) and kanamycin (300 μg/mL) treating P.haitanensis thallus for 24 hours.The combination of antibiotics could obviously inhibit the microbes and had no side effects on the growth of Pyropia.The discs in different strains of P.haitanensis,different-day-old and culture density of P.haitanensis,different salinity and concentration of medium were all growing faster in antibiotics treated groups than control group.Moreover,two special bacteria strains,whose morphology of colonies and strains were different between antibiotics treated groups and control group,were found after comparing bacteria strains isolated from antibiotic treated groups and control group.Based on the above results,a certain type of microorganism multiply rapidly which inhibit growth of the other microorganism that were benefited for the growth of P.haitanensis thallus.When the microorganism that inhibit growth were inhibited with antibiotics,the probiotics became the advantage group and promoted the growth of blades.The probiotics was not sensitive to antibiotics,but with the change of culture condition,the effect of antibiotics on the strains that inhibited the growth of Pyropia became weaker,thus they multiplied rapidly,as a result,hindering the growth of Pyropia thallus.