微生物学通报
微生物學通報
미생물학통보
MICROBIOLOGY
2008年
9期
1385-1392
,共8页
段菁菁%刘立明%华兆哲%陈坚
段菁菁%劉立明%華兆哲%陳堅
단정정%류립명%화조철%진견
活性氧胁迫%过氧化氢酶(CAT)%ATP%NADH%NAD+
活性氧脅迫%過氧化氫酶(CAT)%ATP%NADH%NAD+
활성양협박%과양화경매(CAT)%ATP%NADH%NAD+
Reactive oxygen species stress%Catalase (CAT)%ATP%NADH%NAD+
将一株能够高产过氧化氢酶的低度嗜盐嗜碱茵Alkalibacterium sp.F26作为模式微生物,采用高效液相色谱技术测定胞内代谢物浓度,研究氧化胁迫对其防御酶活性和辅因子的影响.研究结果表明:相比低浓度H2O2(＜1 mmol/L)胁迫,此菌株在高浓度H2O2(＞1 mmol/L)胁迫下的应答表现曼为明显:经3 mmol/L H2O2胁迫后胞内CAT酶活为106.54 U/mg protein,是对照产量的1.76倍;ATP浓度则从对照浓度20.55 μmol/L下降到17.80 μmol/L;NAD+浓度自对照样品的69.89 μmol/L减少至31.77 μmol/L.由于ATP和NAD+浓度的减少,相比未经过H2O2胁迫菌体.细胞能荷值EC从0.77降低至0.68,NADH/NAD+则从0.08增加至0.41.然而,这种应答机制在细胞受到低浓度H2O2的胁迫后并不明显:除发现100 μmol/L H2O2能够导致细胞防御机制的激活而使胞内ATP浓度相比对照有所增加的情况外,经50 μmol/L和500 μmol/L H2O2胁迫后胞内ATP水平从对照的22.69 μmol/L只下降到22.38 μmol/L和13.70 μmol/L;并且此种胁迫条件下NADH浓度变化也不显著.
將一株能夠高產過氧化氫酶的低度嗜鹽嗜堿茵Alkalibacterium sp.F26作為模式微生物,採用高效液相色譜技術測定胞內代謝物濃度,研究氧化脅迫對其防禦酶活性和輔因子的影響.研究結果錶明:相比低濃度H2O2(＜1 mmol/L)脅迫,此菌株在高濃度H2O2(＞1 mmol/L)脅迫下的應答錶現曼為明顯:經3 mmol/L H2O2脅迫後胞內CAT酶活為106.54 U/mg protein,是對照產量的1.76倍;ATP濃度則從對照濃度20.55 μmol/L下降到17.80 μmol/L;NAD+濃度自對照樣品的69.89 μmol/L減少至31.77 μmol/L.由于ATP和NAD+濃度的減少,相比未經過H2O2脅迫菌體.細胞能荷值EC從0.77降低至0.68,NADH/NAD+則從0.08增加至0.41.然而,這種應答機製在細胞受到低濃度H2O2的脅迫後併不明顯:除髮現100 μmol/L H2O2能夠導緻細胞防禦機製的激活而使胞內ATP濃度相比對照有所增加的情況外,經50 μmol/L和500 μmol/L H2O2脅迫後胞內ATP水平從對照的22.69 μmol/L隻下降到22.38 μmol/L和13.70 μmol/L;併且此種脅迫條件下NADH濃度變化也不顯著.
장일주능구고산과양화경매적저도기염기감인Alkalibacterium sp.F26작위모식미생물,채용고효액상색보기술측정포내대사물농도,연구양화협박대기방어매활성화보인자적영향.연구결과표명:상비저농도H2O2(＜1 mmol/L)협박,차균주재고농도H2O2(＞1 mmol/L)협박하적응답표현만위명현:경3 mmol/L H2O2협박후포내CAT매활위106.54 U/mg protein,시대조산량적1.76배;ATP농도칙종대조농도20.55 μmol/L하강도17.80 μmol/L;NAD+농도자대조양품적69.89 μmol/L감소지31.77 μmol/L.유우ATP화NAD+농도적감소,상비미경과H2O2협박균체.세포능하치EC종0.77강저지0.68,NADH/NAD+칙종0.08증가지0.41.연이,저충응답궤제재세포수도저농도H2O2적협박후병불명현:제발현100 μmol/L H2O2능구도치세포방어궤제적격활이사포내ATP농도상비대조유소증가적정황외,경50 μmol/L화500 μmol/L H2O2협박후포내ATP수평종대조적22.69 μmol/L지하강도22.38 μmol/L화13.70 μmol/L;병차차충협박조건하NADH농도변화야불현저.
In this paper,a slight halophilic alkaliphile swain,Alkalibacterium sp.F26,which produced high level of intracellular CAT observed in previous research,was selected as a model microbial to explain the responses of this bacterium to oxidative stress.The results indicated that Alkalibacterium sp.F26 had obvious responses to higher concentration (＞1 mmol/L) of H2O2 than that to lower H2O2 (＜1 mmol/L) challenge from the aspects of defensive enzyme synthesis and cofactors level variation.As for catalase production,the activity increased up to 106.54 U/rag protein which was 1.76 fold of the control when cells were challenged by 3 mmol/L H2O2,but its activity only was 1.13 fold when H2P2 was 100 μmol/L.As far as energy state was concerned,ATP production and NAD+ generation were significantly inhibited from 20.55 μmol/L to 17.80 μmol/L and 69.89 μmol/L to 31.77 μmol/L,respectively,leading to the drop of energy charge from 0.77 to 0.68 and the increase of the portion of NADH/NAD+ from 0.08 to 0.41 in the former case.However,these effects were less distinct under lower concentration of H2O2.Except of the condition of 100 μmol/L H2O2,under which the activation of defensive mechanism resulted in an increase of ATE the level of ATP dropped from 22.69 μmol/L of the control to 22.38 μmol/L and 13.70 μmol/L when challenged by 50 μmol/L and 500 μmol/L H2O2.Besides,the concentration of NADH fluctuated and the NAD+ gradually reduced when H2O2 below 1 mmol/L.
