温室条件下UV-B辐射对蓝藻结皮生长和超微结构的影响

UV-B辐射是野外蓝藻结皮经常面临的一种环境胁迫因子.报道了温室条件下UV-B辐射对蓝藻结皮形态、生理和超微结构特征的影响.在本研究中,首先通过接种具鞘微鞘藻和爪哇伪枝藻形成初始蓝藻结皮,接着以初始蓝藻结皮为材料进行3种辐射处理:光合有效辐射、UV-B辐射+光合有效辐射和N-乙酰半胱氨酸+UV-B辐射+光合有效辐射.在...     

Inactivation of Cryptosporidium by ozone and cell ultrastructures

The fluorescence staining method and scanning electron microscopy (SEM) were used to study the effect of ozone (O3) inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily.Results indicated that O3 had a stronger inactivating capability.When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min,a significant inactivating effect could be achieved.The turbidity on inactivation effects was also found to be statistically significant in artificial water.With increases in turbidity,the inactivating effect decreased.Inactivation rate improved with a temperature increase from 5 to 25°C,but decreased beyond this.The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions.When the concentration of organic matter in the reaction system was increased,the competition between Cryptosporidium and organics with O3 probably took place,thereby reducing the inactivation rate.In addition,the cellular morphology of Cryptosporidium varied with different contact times.At zero contact time,cells were rotundity and sphericity,at 60 sec they became folded,underwent emboly,and burst at 480 sec,the cell membrane of Cryptosporidium shrinked and collapsed completely.     

实验室条件下蓝藻结皮对低温光照胁迫的响应与微结构变化

低温光照是荒漠化地区蓝藻结皮经常面临的环境条件之一.报道了实验室条件下低温光照处理对蓝藻结皮形态、生理特性和超微结构的影响.本研究中,首先通过接种具鞘微鞘藻和爪哇伪枝藻形成人工蓝藻结皮,接着以人工蓝藻结皮为材料进行低温光照处理:28℃+60μE.(m2.s)-1(对照)、10℃+60μE.(m2.s)-1、2℃+60μE.(m2.s)-1和2℃+黑暗.在不同低温光照处理的第0、5和12 d分别测定蓝藻结皮光合活性(Fv/Fm)、叶绿素a、胞外多糖、伪枝藻素、类胡萝卜素和藻蓝蛋白的含量及藻蓝蛋白/叶绿素比值,同时采用扫描电镜观察低温光照处理下蓝藻结皮的微结构变化.此外,对结皮的表观形态特征如结皮颜色、厚度和干重等进行了测定.与对照结皮相比,低温光照下结皮的表观形态受到不利影响,所测定的结皮各项生理指标均呈现显著下降(P<0.05).在2℃+60μE.(m2.s)-1处理12 d时,结皮生物量、光合活性、胞外多糖含量、伪枝藻素含量、类胡萝卜素含量和藻蓝蛋白含量分别比同期对照结皮下降了61.48%、94.89%、66.37%、31.01%、59.38%和65.91%.电镜观察表明,低温光照导致蓝藻结皮的超微结构受到明显破坏,表现为结皮层出现大量蜂窝状空隙,藻丝体数量减少,呈网格状分布,对沙粒的束缚能力减弱等.研究表明低温光照对蓝藻结皮的形态和生理活性具有明显的抑制效应,而低温黑暗能较好地促进蓝藻结皮生理活性和结皮表观形态的恢复.本研究初步探索了蓝藻结皮对低温光照胁迫的耐受性,同时对于了解蓝藻结皮在野外极端环境条件下的生存状况具有一定的理论意义.     

二氧化氯对摇蚊幼虫表皮和肌肉细胞超微结构的影响

通过扫描电镜和透射电镜观察,综合分析了二氧化氯对摇蚊幼虫表皮和肌肉细胞超微结构的影响。研究结果表明:二氧化氯处理后的摇蚊幼虫表皮由于真皮细胞结构被破坏导致板层结构消失,真皮细胞层与内表皮层相分离。真皮细胞的损害表现为核仁变形、染色质固缩;线粒体内嵴减少、解体、空泡化;内质网减少,小池扩张、囊泡化,表面核糖体数量减少。中毒的肌肉细胞内核仁变形;线粒体内嵴溶解,空泡化严重。