Fluctuating salinity effect on Sphoeroides annulatus (Jenyns 1842) physiological responses

Euryhaline fish, such as the Bullseye puffer Sphoeroides annulatus (Jenyns 1842), experience sudden salinity changes in their natural environment, which is more common than the exception, so they must adapt to survive and cope with extreme salt conditions. Therefore, Bullseye puffer juveniles were exposed to short‐term stress (39 hr) by fluctuating salinity conditions (41, 35, 29, 23, 17, 11, 5, 11, 17, 23, 29, 35, 41 psu) with a 3‐hr interval between each point at 26 ± 1ºC in a respirometer chamber and acclimation reservoirs. Responses to oxygen consumption rate (OCR: 23–35 mg O₂ h^–1 kg^–1), ammonium excretion rate (AER: 1–1.85 mg NH4⁺ h^?1 kg^?1), oxygen‐nitrogen atomic ratio (O:N 17–30), osmoregulatory pattern (blood osmotic pressure from 342.4 to 332.8 mmol/kg) and changes in expression levels of Na⁺/K⁺‐ATPase in the gills (higher values at higher salinities) were measured. Although some signs of stress were detected below the iso‐osmotic point (11.4 psu), the puffer fish is a strong euryhaline fish that survives under these conditions. Nonetheless, it could recover when salinity returned to the initial acclimation point because Sphoeroides annulatus is able to live in a wide range of environments with wide natural salinity fluctuations; thus, a common practice in aquaculture has been to expose fish to low salinity for several reasons discussed in this study. This capacity reveals its high plasticity to saline adaptation from 41 to 5 psu an up from 5 to 41 psu, all in less than 2 days.     

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC₉₀ of cinnamaldehyde against different Candida isolates ranged 100–500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H⁺-ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.     

生长阶段及温度对微藻细胞总ATP酶活性的影响

以亚心形扁藻(Platymonas subcordiformis)、大溪地球等鞭藻(Isochrysis galbana daxidi)和小新月菱形藻(Nitzschia closterium)为实验对象,探讨批次培养过程中不同生长阶段及不同温度处理的藻细胞总ATP酶活性.结果表明:三种微藻在不同生长阶段的细胞总ATP...     

膜脂组成和膜结合酶活性与玉米幼苗抗冷性的关系

玉米黄化幼苗经4～5℃低温处理36小时后,膜脂组成在自交系间、处理和对照间没有差异;膜脂肪酸不饱和度发生明显变化,抗性强的自交系不饱和指数提高,抗性差的不饱和指数降低,膜结合酶(叶绿体K~+-Mg~(2+)ATPase和线粒体Na~+-K~+ATPase)活性降低,抗性差的自交系膜结合酶活性降低幅度大于抗性强的自交系。     

氟对牛脾淋巴细胞膜ATP酶活性的影响

取健康牛脾脏,常规方法分离培养淋巴细胞,用不同浓度氟化钠（NaF）染毒24h。低渗溶胞法提取细胞膜,检测膜上ATP酶活性。结果显示,与对照组相比较,染氟组淋巴细胞膜ATP酶活性降低,组间差异显著或极显著。表明：氟能抑制牛脾淋巴细胞膜ATP酶活性。     

供铁水平对不同苹果基因型生长及根系特性的影响

以小金海棠 (MalusxiaojinensisChengetJiang)和山定子 (MalusbaccataL .Borkh)为试材 ,研究供铁水平对其生长及根系特性的影响 ,结果表明 ,在幼苗生长量、新叶叶绿素含量、营养液pH日变化、根系活力、根系ATP酶活性诸方面 ,存在基因型差异。同一供铁水平 ,小金海棠有明显的铁胁迫反应 ,而山定子铁胁迫反应较弱。低铁胁迫处理 ,小金海棠叶片叶绿素含量、根系活力、根系ATP酶活性皆明显高于山定子。根系活力及根系ATP酶活性可用作铁高效基因型植物的筛选指标     

大田遮荫对紫心甘薯块根中酶活性的影响

在大田条件下,采用人工遮荫的方法探讨光照不足导致紫心甘薯块根品质下降的酶学机制。研究结果表明:在遮荫条件下,2个甘薯品种济薯18和Ayamurasaki叶片RUBPCase活性显著降低;叶片和块根中ATPase活性下降;块根ADPGPPase和UDPGPPase活性均显著降低,降低幅度随胁迫强度而增加;遮荫对块根可溶性淀粉合成酶(soluble starch synthase,SSS)和淀粉粒结合态淀粉合成酶(granulebound starch synthase,GBSS)活性的影响存在品种间差异,济薯18块根SSS活性显著降低,GBSS活性则不同程度高于对照,而Ayamurasaki的SSS活性却高于对照,GBSS活性则随遮光胁迫强度而降低;遮荫对花青素合成的关键酶苯丙氨酸解氨酶(Phenglalanine Ammonia Lyase,PAL)活性影响则很小。因此,遮荫胁迫从源库流各环节影响了紫心甘薯品质合成相关酶,其中RUBPCase、ATPase、ADPGPPase和UDPGPPase活性显著降低是导致紫心甘薯块根品质下降的主要原因。     

喹禾灵对映体对斑马鱼毒性的手性选择性研究

为了研究喹禾灵对映体对水生生物的手性选择性毒性,对喹禾灵对映体进行了斑马鱼急性毒性试验,并研究了亚致死水平上对斑马鱼体内ATP酶活性的影响。研究发现,精喹禾灵和喹禾灵对斑马鱼的急性毒性分别为高毒和低毒;二者在诱导时间和诱导强度上对斑马鱼体内Na+,K+-ATP酶和Ca2+-ATP酶活性均表现出不同的作用方式。喹禾灵对斑马鱼Ca2+-ATP酶活性的影响在72 h时,250μg.L 1、1 000μg.L 12个处理组表现出明显诱导效应(P<0.05),在96 h各处理组均表现出诱导作用。精喹禾灵除在24 h时,5μg.L 1、10μg.L 1处理组外,其他各处理组对斑马鱼体内Ca2+-ATP酶表现出较强的诱导作用;72 h后,25μg.L 1、100μg.L 1处理组酶活性有下降趋势,其他2个处理组酶活性则继续增加。喹禾灵对斑马鱼Na+,K+-ATP酶活性的影响在48 h时,250μg.L 1、1 000μg.L 12个处理组有明显诱导效应(P<0.05),72 h时只有1 000μg.L 1处理组有明显诱导作用。精喹禾灵25μg.L 1、100μg.L 1处理组在24 h时对Na+,K+-ATP酶活性即表现出很强的诱导效果,48 h后各处理组酶活性都开始明显增加;72 h时各浓度处理组酶活性有下降趋势,96 h后基本与对照组无显著性差异。试验结果表明喹禾灵对映体对斑马鱼毒性有显著的手性选择性。     

水杨酸与高温锻炼对高温胁迫下葡萄叶肉细胞质膜ATPase活性的影响

采用水性两相分配法对经水杨酸(SA)和高温锻炼处理过的葡萄幼苗叶肉细胞中ATPase进行了分离和测定.结果表明:高温下,细胞质膜ATPase活性随着胁迫程度的加深均呈下降趋势,经SA和高温锻炼预处理后再经高温胁迫,发现质膜ATPase的活性低于正常条件下的水平(CK1),但明显高于未经处理直接进行高温胁迫后ATPase活性水平,即高温锻炼和SA预处理的质膜酶活仍保持了较高的活性,并且后一种处理效果更明显.说明质膜上ATPase活性的变化对高温胁迫作出了一定的响应,SA和高温锻炼对提高葡萄幼苗叶片的抗热性与二者可以维持细胞质膜上ATPase活性的稳定有关.     

Effects of Exogenous Cinnamic Acids on the Growth and Physiological Characteristics of Cucumber Seedlings

In order to study the effects of exogenous cinnamic acids on plant growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane at cucumber seedling stage, the seedlings of Shandong Mici cucumber were tested. The results showed that seedlings growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane were inhibited by cinnamic acids. The growth and root activities of seedlings were significantly （P〈0.05） lower in the soil amended with 100 mg kg^-1 cinnamic acids compared to the control. The contents of chlorophyll a, chlorophyll a＋b and carotenoid of seedlings significantly （P〈0.05） decreased in the soil amended with 200 mg kg^-1 cinnamic acids, whereas ATPase activities exhibited a higher sensitivity and greatly decreased in the soil amended with 50 mg kg^-1 cinnamic acids. These results suggested that cinnamic acids could induce a stress condition, and the stress intensities increased with enhanced cinnamic acid concentration.