盐胁迫对非洲凤仙花实生苗细胞膜透性和丙二醛含量的影响

用NaCl 50、100、150、200、250 mmoL/L处理非洲凤仙花实生苗,处理10、20、30 d后取叶片测定其细胞膜透性、丙二醛含量。结果表明:NaCl处理10 d的非洲凤仙花叶片细胞膜透性保持稳定,随盐浓度的增加及处理时间的延长,叶片细胞膜透性逐渐增加。整个处理过程中,丙二醛含量逐渐增加,但增加幅度不大,表明脂质过氧化反应水平较低。     

Membrane performance and fouling behavior of membrane bioreactors installed in marine recirculating aquaculture systems

Accumulation of fine suspended solids and colloids in a recirculating aquaculture system (RAS) can be avoided by integrating a membrane filtration unit into the system, where the inclusion of a membrane bioreactor (MBR) may be an alternative. The main purpose of the study was to identify how the feeding regime affected membrane performance and fouling phenomena caused by dissolved and submicron colloidal particles in the system, and how the membrane impacted general water quality and particle characterization. To be able to evaluate membrane performance and fouling behavior, transmembrane pressure (TMP) was monitored and assessed in relation to changes in rearing conditions and different water quality parameters observed. From this study the positive influence on the chosen water quality parameters was apparent, where an improved water quality was observed when including a membrane filtration in RAS. Selected water quality parameters and TMP changed during the experimental period in response to the feeding regime, where algae paste, decaying rotifers and dry feed seemed to contribute the most to membrane fouling. Analysis of the concentration of submicron particles and particle size distribution (PSD) (particles < 1 μm) showed both a higher concentration and a more spread distribution in the rotifer/algae paste and dry feed period compared to the Artemia period, which might explain the observed increase in fouling. This study also showed that adapted procedures for concentrate removal are important to prevent hydrolysis of retained particles in the concentrate and leakage of nutrients and organic matter back to the system.     

奶牛Y精子膜蛋白的提取与分析

奶牛Y精子膜蛋白的提取与鉴定为深入研究Y精子特异膜蛋白在受精过程中的作用，开发经济、安全、高效的奶牛性别控制方法具有重要意义。本研究采用超声波破碎法将精子膜与精子分离，分离后的精子膜粗品采用蔗糖密度梯度离心法进行纯化。纯化的精子膜经膜蛋白提取液（去污剂）提取，透析浓缩。经变性聚丙烯酰胺凝胶电泳（SDS—PAGE）银盐染色，成功地提取到膜蛋白。BIO—RAD凝胶成像分析仪分析得知Y精子膜蛋白至少有10种，分子量范围为7．94KD-166．65KD，其中尤以15KD的蛋白含量最多。     

掌裂草葡萄对NaCl胁迫的生理适应性研究

掌裂草葡萄是观赏价值很高的多年生藤本植物，在寒地园林垂直绿化中具有很好的推广价值。目前对其抗盐性研究未见报道。本试验通过对掌裂草葡萄一年生播种苗进行不同浓度的NaCl胁迫处理，研究其细胞膜透性，渗透调节物质（可溶性糖、可溶性蛋白）、保护酶活性（SOD、POD）在盐胁迫下的变化规律，揭示掌裂草葡萄的耐盐性。结果表明：掌裂草葡萄对NaCl胁迫有一定的应激性，胁迫使可溶性蛋白含量和SOD活性迅速增大；各处理随胁迫时间的延长膜透性逐渐增大，胁迫浓度越大，电解质外渗越多。400mmol／L胁迫处理第18d，电解质外渗达50％以上，处理第30d植株死亡；浓度300mmol／L及以上时，可溶性糖、可溶性蛋白和SOD活性在处理第18d开始迅速下降，POD活性在处理第30d下降，可溶性糖含量和SOD活性分别在第24d和第30d低于对照。由此推断，300mmol／L及以上的NaCI胁迫不利于掌裂草葡萄的生长。     

Phytotoxic activity of middle-chain fatty acids II: peroxidation and membrane effects

Pelargonic acid (PA), an aliphatic 9-carbon monocarboxylic acid, is a phytotoxic burn-down compound. In the light peroxidizing activity can be measured as ethane and propane formation with cress or tobacco seedlings. This effect is strong at low pH (4–5), and saturated acids with 9–10 carbon atoms represent the optimum chain length. Methyl or ethyl esters are inactive, and safeners have no influence. In contrast to the peroxidative herbicides like acifluorfen methyl neither photosynthesis nor protoporphyrin IX is involved, although peroxidation requires light. Chlorophyll is necessary since etiolated seedlings show little peroxidation. Singlet oxygen quenchers like eugenol markedly reduce peroxidation. Membrane leakage of a similar rate is observed in light as well as in darkness. PA was described as a penetration enhancer intercalating with membranes. Our data corroborate that conclusion. Accordingly, the herbicidal mode of action of pelargonic acid is due first to membrane leakage in dark or light and second to peroxidation driven by radicals originating in the light by sensitized chlorophyll displaced from the thylakoids.     

Cellular compartmentation and membrane permeability to sugars in relation to early or high temperature-induced watercore in apples

Early watercore was observed in apples (Malus domestica Borkh.) from the outer canopy of ‘Orin’, an early watercore susceptible cultivar, while there was no watercore in ‘Orin’ fruit from the inner canopy and resistant ‘Fuji’. Sorbitol content was higher not only in the free space but also in the vacuole and cytoplasm in watercored ‘Orin’ than in other non-watercored fruit. Comparing watercored apples to non-watercored fruit of ‘Orin’, higher fructose and glucose in the vacuole and no significant difference in the distribution rate of sorbitol to each compartment were observed. Watercored ‘Orin’ apples showed significantly higher permeability of tonoplast to fructose, glucose, and sorbitol than those in other non-watercored apples. The permeability of plasma membrane to each sugar was much higher than that of tonoplast but no marked difference was observed among the treatments. The results suggest that metabolism of sorbitol could be active even in watercored ‘Orin’ apples and the accumulated sorbitol in the intercellular spaces might be primarily due to an active unloading from the phloem and not be brought by increased leakage from the cells.     

Immunohistochemical localization of phospholipase D in strawberry (Fragaria ananassa Duch.) fruits

Phospholipase D, the key enzyme involved in membrane phospholipid catabolism, was localized in strawberry (Fragaria ananassa Duch.) fruits during development using immunohistochemical techniques. Typical structural features such as the nucleus, cell wall, plasma membrane, mitochondria and vacuole were noticeable in cells of young strawberry fruits. Cytoplasmic structural features were less pronounced in fully grown and turning red fruits, except cell wall, which was considerably enlarged. Also, extensive microvesiculation from the plasma membrane was noticeable in ripening fruits. The number of visible gold particles indicative of phospholipase D increased during development. Phospholipase D was found to be associated with membranous structures and vacuole. Interestingly, gold-particles could also be observed in the cell wall space in ripening fruits suggesting that cytosolic contents may have leaked into the cell wall space as a result of membrane deterioration and loss of compartmentalization. The role of phospholipase D during development and ripening of strawberry, a non-climacteric fruit, is discussed.     

Vascular endothelial growth factor concentrations in body cavity effusions in dogs

Vascular endothelial growth factor (VEGF) has potent angiogenic, mitogenic, and vascular permeability enhancing properties specific for endothelial cells. VEGF is present in high concentrations in inflammatory and neoplastic body cavity effusions and has been implicated in the pathogenesis of neoplastic and inflammatory effusion formation. In this study, VEGF was quantitated by solid-phase enzyme-linked immunoadsorbent assay (ELISA) in samples of pericardial, pleural, and peritoneal effusions (N = 38) from dogs (N = 35) with neoplastic and non-neoplastic diseases. VEGF was detected in 37 of 38 effusions (median, 754; range, 18-3,669 pg/mL) and was present in much higher concentrations than in previously established normal concentrations for canine plasma (median, < 1 pg/mL; range, < 1-18 pg/mL) or in those previously noted in the plasma of dogs with hemangiosarcoma (HSA; median, 17 pg/mL; range, < 1-67 pg/mL). In 4 dogs with HSA, the concurrent plasma VEGF concentration was much lower than in the abdominal effusion (P = .029). No significant correlation was demonstrated between VEGF effusion concentration and effusion total protein content or nucleated cell count. Mean VEGF concentrations were significantly higher in pericardial (median, 3,533; range, 709-3,669 pg/mL) and pleural effusions (median, 3,144; range, 0-3,663 pg/mL) compared to peritoneal effusions (median, 288; range, 18-2,607 pg/mL; P < .05). There was no marked difference demonstrated between effusions associated with malignant and nonmalignant diseases. Further studies are necessary to elucidate the role of VEGF in body cavity effusion formation in dogs.     

红菜薹的抗冻性

以１９份红菜薹材料为试材,将离体叶片组织经过系列冷冻低温处理后测定电导率,进而计算细胞膜伤害率,然后用Ｌｏｇｉｓｔｉｃ方程拟合细胞膜伤害率与温度的关系,求出拐点温度来估计材料的低温致死温度。结果表明：拐点温度能准确估计红菜薹的抗冻性;红菜薹的低温致死温度因材料而异,在－５～－１１℃之间;抗冻性与农艺性状的关系表现为越晚熟抗冻能力越强,总莲座叶数越多抗冻能力也越强,同时也有植株越高大抗冻能力越强的趋势。     

酶活性与黄瓜对霜霉病抗性的关系

研究了多酚氧化酶和过氧化物酶活性与黄瓜对霜霉病抗性的关系。结果表明黄思苗在感病期间,不同品种叶片质膜透性的增大与这两种酶活性有密切关系,抗病性强的,质膜透性增幅增低,酶活性高;反之,抗病性弱的,质膜透性增效大酶活性低。