玉米(Zea mays L.)中单14号及亲本叶绿体的组分和功能比较

玉米中单１４号的叶绿体在叶绿素含量、光能吸收、电子传递速率、激发能分配和色素蛋白复合体组成等方面均优于两亲本。其叶绿素ａ、ｂ和总含量提高了３１％￣３６％；对光能吸收强度较大；光还原活力超过双亲２５．５％；分配到ＰＳＩ的激发能比亲本多１４７．１％；叶绿素蛋白复合体分析结果说明，其捕光色素蛋白复合体含量高于亲本。因而中单１４号比亲本在叶绿体的光合功能上显示优势。     

小粒种咖啡光合特性的研究

自然状况下,小粒种咖啡树冠外围向阳叶的叶绿素a/b值及其光谱吸收能力都较树冠内层荫蔽叶以及同龄的人工遮荫叶大,且其叶绿体的DCPIP光还原活性和乙醇酸氧化酶活性也都较强,呼吸速率较高,但其叶绿素含量(mg/g)却较低。小粒种咖啡树冠外围向阳叶光合作用的光饱和点约为40klx,内层荫蔽叶和用3层纱布遮荫1.5个月左右的人工遮荫叶部约为15klx。向阳叶在其光饱和点时的光合速率高于荫蔽叶光饱和点时的光合速率;当光照强度处于荫蔽叶的光饱和点时,荫蔽叶的光合速率高于向阳叶;当光照强度超过各自的光饱和点时,向阳叶和荫蔽叶的光合速率都明显下降,即都出现明显的光抑制现象,但这时向阳叶的光合速率仍高于荫蔽叶。小粒种咖啡光合作用的低温界限约比5℃稍高,在本实验高CO_2浓度条件下,温度高达40℃时,其光合速率仍未降低。     

NBT-PABA test to assess efficiency and kinetics of substituted proteolytic enzyme action in pancreatic duct ligated minipigs

The NBT-PABA test is an established method for diagnosis of pancreatic exocrine insufficiency. In the present study the NBT-PABA test was used to test and compare the efficacy of two multienzyme preparations (product A and B) differing in galenic preparation in minipigs in which pancreatic exocrine insufficiency (PEI) was induced by pancreatic duct ligation. Without enzyme substitution no distinct increase in PABA was found in blood after oral administration of NBT-PABA. Administration of both enzyme preparations led to a clear dose dependent rise in PABA-concentrations in blood. Interestingly, the two preparations showed different time curves of serum PABA concentration, indicating differences in the kinetic of proteolytic enzyme action. It is concluded that the NBT-PABA test can be a very useful test for indirectly evaluating proteolytic enzyme efficacy in vivo, and also gives information about the kinetics of enzyme action, not only the end-result of enzyme action (like digestibility trials which were used traditionally). A single test is performed in a few hours and there is no need for fistulated animals.     

Combined phagocytosis-nitroblue tetrazolium reduction test in bovine neutrophils

An assay was developed for the simultaneous evaluation of phagocytosis and oxidative metabolism of bovine blood neutrophils. Phagocytosis was evaluated by using opsonized zymosan, and oxidative metabolism was evaluated by nitroblue tetrazolium (NBT) reduction. Normal bovine neutrophils exhibited moderate variation in ability to phagocytize zymosan, but little variation in ability to reduce NBT. The subcellular location of NBT reduction to formazan was determined by electron microscopy. Electron dense formazan precipitate was observed along the inner membrane of phagosomes enclosing zymosan particles and radiating from the membrane toward the center of the phagosome.     

银杏叶提取物对氧自由基的影响

分别提取银杏叶脂溶性成分和水溶性成分,采用NBT(氯化硝基四氮唑蓝)光还原法检测银杏叶提取物消除氧自由基能力的大小,并计算出抑制率。结果表明:银杏叶脂溶性成分和水溶性成分均能消除氧自由基,水溶性成分消除氧自由基的能力强于脂溶性成分。水溶性提取物组的活力单位是0.167mg,脂溶性提取物NaOH组的活力单位是0.17mg,脂溶性提取物无水乙醇组的活力单位是0.795mg。     

60种蔬菜抗氧化作用的研究

采用黄嘌呤氧化酶 - NBT法对 2 0个科 6 0种蔬菜进行了抗氧化作用的研究。结果显示 :6 0种蔬菜中有 9种抑制率在 5 0 %以上 ,占 15 % ,具有较强的抗氧化作用 ;2 6种蔬菜的抑制率在 30 %～ 5 0 %之间 ,有一定的抗氧化作用。表明从蔬菜中寻找具抗氧化作用的物质是可行的     

高含量超氧化物歧化酶植物的筛选

用氮蓝四唑法测定了１６３种植物叶片或果实中超氧化物歧化酶的催化活性，并以此催化活性表示酶的含量。结果表明：草本植物与木本植物，农作物与非农作物之间的ＳＯＤ含量分布差异不大，但各科植物之间含量差异较大。     

水培条件下pH对大蒜生长趋势的影响

[目的]研究水培大蒜在不同pH条件下的生长发育及SOD活性变化。[方法]土壤溶液的pH对植物的生长发育有重要的影响,试验以不同梯度的pH水溶液水培大蒜,在不同生长阶段对其SOD活性进行测定。试验采用丙酮沉淀法分离纯化SOD沉淀,用NBT光还原法测定其活性。[结果]水培大蒜在pH为6.0时长势最好。在pH 4.55.5的生长环境下,大蒜的SOD活性相对稳定,但伴随着逐渐生长,SOD活性呈现上升趋势。酸性环境下,SOD活性相对较高。[结论]该研究可为大蒜的水培提供指导。     

Fenvalerate induced stress mitigation by dietary supplementation of multispecies probiotic mixture in a tropical freshwater fish, Labeo rohita (Hamilton)

Five experimental diets with various combinations of probiotics, namely T1 & T6 (basal feed (BF) without probiotics), T2 & T7 (BF + Bacillus subtilis + Lactococcus lactis), T3 & T8 (BF + L. lactis + Saccharomyces cerevisiae), T4 & T9 (BF + B. subtilis + S. cerevisiae) and T5 & T10 (BF + B. subtilis + L. lactis + S. cerevisiae) were fed to Labeo rohita fingerlings for 30 days. Treatment groups T1, T2, T3, T4 and T5 were exposed to Fenvalerate, at a concentration of 1.79 μg L⁻¹. The SOD and CAT activity was significantly affected (P < 0.01) in fenvalerate treated groups. However, the supplementation of the three-probiotic mixture at equal concentration showed markedly reduced activity. Similarly, RBC, Hb, NBT, total protein and albumin values were reduced significantly (P < 0.01) in the fenvalerate exposed fish as compared to the probiotic supplemented fish. Fenvalerate exposure also showed increased serum ALP, ACP and Bilirubin values (P < 0.01) in comparison to the non-exposed fish. Histological observations of the gills, kidney and liver showed tissue degeneration after fenvalerate exposure, which however showed marked recovery on the three-probiotic mixture supplementation. Therefore, these results indicate that a mixture of multi-species probiotic supplementation in equal concentration acts beneficially in mitigating the stressful effects of fenvalerate.