摘要
[目的]本文旨在研究碳酸酐酶(SCA)对猪链球菌生长及抗氧化应激的影响,并分析其生物学功能。[方法]以猪链球菌2型野生株SC070731为背景,构建sca缺失株Δsca,通过测定不同条件下的生长曲线和H 2O_(2)应激、小鼠巨噬细胞RAW264.7吞噬与存活、猪全血存活等试验,评价SCA对猪链球菌生长及抗氧化应激的影响。[结果]与野生株相比,Δsca株在缺乏CO_(2)条件下的生长受到显著抑制,生长12 h A 600值低于0.5;在5%CO_(2)条件下,虽然Δsca株的迟缓期较野生株长,但平台期其恢复到与野生株相同的水平,A 600值均接近1.6;在缺乏CO_(2)条件下,添加NaHCO_(3)可显著刺激Δsca株生长,且与浓度呈正相关;添加不饱和脂肪酸(UFA)油酸或Tween-80、Tween-20等UFA衍生物均可显著促进Δsca株生长。经H 2O_(2)作用20 min后,野生株存活率为99.48%,而Δsca株存活率为74.04%(P<0.01)。吞噬试验表明,RAW264.7对野生株和Δsca株的吞噬率无显著差异;存活试验表明,经抗生素处理3 h后,野生株的存活率为77.98%,而Δsca株在RAW264.7内的存活率显著降低,仅为38.93%(P<0.01)。猪全血存活试验表明,与野生株的存活率(110.02%)相比,Δsca株在猪全血中的存活率为51.39%(P<0.01)。[结论]SCA促进猪链球菌利用CO_(2)和HCO-3,并参与UFA合成,因而有助于猪链球菌的生长及抗氧化应激;该酶促进猪链球菌在猪全血和小鼠巨噬细胞中存活,提示其在猪链球菌致病过程中发挥重要作用。
[Objectives]This article aimed to study the effect of Streptococcus suis carbonic anhydrase(SCA)on the growth and oxidative stress response of S.suis and to analyse its biological functions.[Methods]The deletion mutant strainΔsca was constructed using S.suis wild-type strain SC070731,and the effect of SCA on the growth of S.suis under different conditions including H 2O_(2) treatment was evaluated;the assay of mouse macrophage cells RAW264.7 phagocytosis and survival,and pig blood survival were performed.[Results]Compared with the wild-type strain,the growth ofΔsca strain in the absence of CO_(2) was significantly inhibited,and its A 600 value of 12 h growth was lower than 0.5.Under the condition of 5%CO_(2),although the lag phase ofΔsca strain was longer than that of the wild-type strain,the A 600 values of both wild-type strain andΔsca strain were close to 1.6 at stationary period;in the absence of CO_(2),with the gradient increase of NaHCO_(3) concentration in the medium,the growth ability ofΔsca strain was significantly improved.Compared withΔsca strain,adding unsaturated fatty acid(UFA)oleic acid or UFA derivatives such as Tween-80 and Tween-20 significantly promoted the growth ofΔsca strain.The survival rate of the wild-type strains was 99.48%after H 2O_(2) treatment for 20 min,while the survival rate ofΔsca strain significantly reduced to 74.04%(P<0.01).There was no significant difference in the phagocytosis rates of RAW264.7 on the wild-type strain andΔsca strain;the survival assay showed that after 3 hours of antibiotic treatment,the survival rate of the wild-type strain was 77.98%,while the survival rate ofΔsca strain in RAW264.7 significantly reduced to 38.93%(P<0.01).Pig blood survival assay showed that the survival rate of the wild-type strain was 110.02%,but the survival rate ofΔsca strain in pig blood was only 51.39%(P<0.01).[Conclusions]The SCA,necessary for S.suis to utilize CO_(2) and HCO-3,is involved in the synthesis of UFA.Thus,it contributes to the growth and oxidative stress resp
作者
陈琳
王硕玥
姚火春
吴宗福
CHEN Lin;WANG Shuoyue;YAO Huochun;WU Zongfu(College of Veterinary Medicine,Nanjing Agricultural University,Nanjing 210095,China)
出处
《南京农业大学学报》
CAS
CSCD
北大核心
2021年第5期903-910,共8页
Journal of Nanjing Agricultural University
基金
国家自然科学基金项目(31872469)。
关键词
猪链球菌
碳酸酐酶
生长
氧化应激
Streptococcus suis
carbonic anhydrase
growth
oxidative stress
