铜绿假单胞菌的温度、pH值和乳酸钠主参数模型构建

采用全自动微生物生长曲线分析仪Bioscreen测定分离自腐败冷却猪肉的铜绿假单胞菌在不同温度(25~40℃)、pH值(5.0~7.5)、乳酸钠质量浓度(0~0.035 g/mL)影响下的生长曲线。基于最小二乘法运用Matlab软件中的fminsearch函数拟合铜绿假单胞菌迟滞期关于温度、pH值和乳酸钠质量浓度的主参数模型,经参数估计求得铜绿假单胞菌的最低生长温度、最适生长温度、最高生长温度、最低生长pH值、最适生长pH值、最高生长pH值、乳酸钠的最小抑菌浓度,进而通过10组随机数据进行验证。结果表明,构建的主参数模型能较好预测铜绿假单胞菌的相关生长参数,决定系数R2为0.929 1,偏差因子B f为1.097 5,准确因子A f为1.393 6,平方根误差为1.598 9。验证组的决定系数R2为0.854 6,偏差因子B f为1.122 5,准确因子A f为1.211 7,都在可接受的范围内。     

硝磺草酮对微囊藻和四尾栅藻光合作用及竞争的影响

采用纯培养和混合培养方法,结合调制叶绿素荧光测定技术,研究了硝磺草酮对微囊藻和四尾栅藻光合作用及种间竞争的影响。结果表明:0.5~10 mg·L-1硝磺草酮降低了微囊藻和四尾栅藻的最大光化学量子产量(Fv/Fm)和快速光曲线(RLCs)拟合参数(Ik、α、ETRmax),降低幅度与硝磺草酮浓度正相关;处理14 d时,Fv/Fm、Ik、α、ETRmax水平均达到暴露以来最小值,表明微囊藻和四尾栅藻在硝磺草酮处理期间未表现出恢复趋势。对比2种藻荧光参数变幅可知,硝磺草酮对四尾栅藻各荧光参数影响大于微囊藻,表明四尾栅藻的敏感性高于微囊藻。混合培养实验结果显示对照组微囊藻同四尾栅藻相比处于竞争劣势,而5、10 mg·L-1硝磺草酮处理时,微囊藻在与四尾栅藻的种间竞争中逐渐占据优势,且在微囊藻与四尾栅藻初始接种体积比为1∶3的混合培养体系中表现出最强的竞争力。较高浓度的硝磺草酮可使微囊藻由原劣势地位转为逐渐占据竞争优势,故硝磺草酮对水体中蓝藻水华的爆发具有潜在的促进作用。     

侧孢芽孢杆菌对铜绿微囊藻生长胁迫的研究

为探讨侧孢芽孢杆菌(Bacillus laterosporus)SK-1对铜绿微囊藻(Microcystis aeruginosa)生长胁迫的影响,在实验室环境下对两者共适培养基质进行了选择和优化,探究了处于不同生长期和不同初始生物量的上述两者在共基质中的数量消长规律,以及共基质体系中无机氮营养盐(NO-3-N、NO-2-N、NH+4-N)的含量变化。结果显示,将取自富营养化池塘的养殖水,添加适量葡萄糖和氨氮使得C∶N∶P的近似比为250∶10∶1的培养基质作为共适培养基质。在此基质中,不同生长时期的侧孢芽孢杆菌与铜绿微囊藻共存时的生长胁迫效应不同,处于生长稳定期的菌体对生长初期的微囊藻抑制效果最好,且在一定的浓度范围内,菌体细胞密度越大,其抑藻效果越明显。研究表明,侧孢芽孢杆菌对铜绿微囊藻生长的抑制是通过竞争营养物质与分泌胞外抑藻物质这两种方式实现的,且在藻体和菌体的不同生长阶段,这两种作用方式所占的比重不同。故在生态控藻时,须在藻类爆发生长前进行细菌种群的培育,以获得良好的生态效果。     

绿色微囊藻等不同食物对大型生长和脂类成分的影响

The growth and reproduction of Daphnia magna fed with Microcystis viridis and Chlorella spp respectively and 20% fish oil + 80% yeast and yeast were studied. The intrinsic rate of natural increase of Daphnia magna (rm) was 0.243 fed with Microcystis viridis, 0.301 with Chlorella spp., 0.244 with 20% fish oil + 80% yeast and 0.193 with yeast. The result showed that：Daphnia magna fed with Microcystis viridis had lower growth rates than that fed with Chlorella spp. an d 20% fish oil + 80% yeast which both had full fatty acids. And the Daphnia magna fed with yeast was the lowest. So the fatty acids composition of diet may affect the growth of Daphnia magna. This paper further examined total lipids and main HUFA (EPA and DHA) compositions of the continuous three generations of Daphnia magna (in order to get rid of t he effects of former diet) fed with different of above diets (except the yeast). The result showed that:the three generations of the D. magna fed with Microcystis viridis had the lowest total lipids and the percentages of the HUFA (EPA, and no DHA) have a significant decrease and get the lowest EPA in the final experiment because of the very low HUFA especially EPA and DHA in Microcystis viridis. So the results indicate that Microcystis viridis with low HUFA made the lower growth rate, spawn ing rate and hatching rate of Daphnia magna.     

In situ studies on the bioaccumulation of microcystins in the phytoplanktivorous silver carp (Hypophthalmichthys molitrix) stocked in Lake Taihu with dense toxic Microcystis blooms

The phytoplanktivorous silver carp is an important biomanipulation fish to control cyanobacterial blooms and is also a food fish with the greatest production in China. The accumulation of the hepatotoxic microcystins (MCs) determined by LC-MS in various organs of silver carp was studied monthly in Lake Taihu dominated by toxic Microcystis aeruginosa. Average recoveries of spiked fish samples were 78% for MC-RR and 81% for MC-LR. The highest content of MCs was found in the intestine (97.48 μg g^− 1 DW), followed by liver (6.84 μg g^− 1 DW), kidney (4.88 μg g^− 1 DW) and blood (1.54 μg g^− 1 DW), and the annual mean MC content was in the order of intestine > liver > kidney > blood > muscle > spleen > gallbladder > gill. Silver carp could effectively ingest toxic Microcystis cells (up to 84.4% of total phytoplankton in gut contents), but showed fast growth (from 141 g to 1759 g in 1 year in mean weight). Silver carp accumulated less microcystins in liver than other animals in the same site or other fish from different water bodies at similar level of toxin ingestion. There was possible inhibition of the transportation of the most toxic MC-LR across the gutwall. Muscle of silver carp in Lake Taihu should not be consumed during period of dense Microcystis blooms while viscera were risky for consumption in more months.     

微囊藻水华叠加对太湖沉积物中细菌垂直分布的影响

为研究微囊藻水华爆发对沉积物中细菌的影响,加强对富营养化湖泊细菌生态分布和环境调控原理的认识,选取太湖竺山湾沉积物柱状样,经添加高浓度微囊藻培养后,采用聚合酶链式反应-变性梯度凝胶电泳（polymerase chain reaction-denaturing gradient gel electrophoresis;PCR-DGGE）方法,分析细菌在沉积物中的垂直分布特征。结果显示,微囊藻水华叠加对于沉积物剖面表层细菌群落结构影响很小,对沉积物中细菌垂直分布的影响不大,仅在7～9cm深度之间有一定影响。     

微囊藻受短时超声波胁迫蛋白表达差异研究(英文)

为探索微囊藻抵抗短时超声波表达调控相关蛋白质,应用双向电泳技术对微囊藻短时超声波处理蛋白质表达进行分析,结果表明,71个蛋白质点上调,56个蛋白质点下调,54个新增蛋白质点,21个消失蛋白质点。对其中8个差异大的蛋白质点采用MALDA-TOFMS进行质谱分析,并经数据库搜索匹配,鉴定出2个未知蛋白、6个功能蛋白。这些功能蛋白参与抗氧化和抗炎症、磷酸盐合成、电子传递等生理过程,实现微囊藻在短时超声波胁迫下的代谢平衡和自我保护。     

不同试验条件对藻蓝蛋白提取效率的影响

以实验室培养的水华蓝藻单种[铜绿微囊藻(Microcystis aeruginosa,M.A)、水华微囊藻(Microcystis flos-aquae,M.F)、惠氏微囊藻(Microcystis wesenbergii,M.W)、鱼腥藻(Anabaena sp,A.s)]以及野外新鲜水华蓝藻为研究对象,通过设置不同细胞破碎方法和提取剂种类,筛选并优化藻蓝蛋白荧光分析法的前处理技术。结果表明,冻融试验中,冷冻温度与提取剂添加顺序对蓝藻细胞破碎率无显著影响;以去离子水为提取剂时,冻融2次即可达到最佳破壁条件;在冻干试验中,蓝藻真空抽滤在滤膜上能提高蓝藻细胞的破碎率;综合比较冻融和冻干,后者对蓝藻细胞的破碎效率高于前者;对比3种提取剂对藻蓝蛋白的提取效率,去离子水对藻蓝蛋白的提取效率最高。     

大蒜对铜绿微囊藻的化感抑制作用

通过人工培养箱培养的方法,利用分光光度计、酶标仪及相关试剂盒等分别测定铜绿微囊藻在不同浓度(0,0.2,0.4,0.8,1.6,3.2,6.4 g/L)大蒜作用下的生理生化指标变化情况,以期探讨大蒜对铜绿微囊藻的抑制机理。结果表明:大蒜对铜绿微囊藻表现为低促高抑的作用效果,与对照相比,0.2 g/L的大蒜浓度对铜绿微囊藻生长反而略有促进作用;6.4 g/L浓度的大蒜则可有效地抑制铜绿微囊藻的生长,而且随着作用时间的延长其抑制效果愈加明显,在第96小时时铜绿微囊藻的生长抑制率可达53.42%;另外,高浓度大蒜能有效抑制铜绿微囊藻的叶绿素a含量并能影响铜绿微囊藻藻胆蛋白各组分的构成及可溶性蛋白的含量。由此可以得出,一定浓度的大蒜对铜绿微囊藻具有化感抑制作用,且高浓度下的大蒜能通过影响铜绿微囊藻叶绿素a的含量来影响其光合作用,最终导致藻类繁殖受阻。可见,藻类叶绿素a(即PSⅡ)是大蒜抑制铜绿微囊藻生长繁殖的一个作用位点。     

Purification and characterization of the extracellular algae-lysing components from an algae-lysing bacteria

Purification, characterization and initial identification of extracellular algae-lysing constituents of fermentation products of the algicidal bacteria S7 are carried out by ultraviolet spectrum, infrared spectrum, fluorescence spectra and mass spectrum, and the results show that the eluates of methanol have the best algicidal effects. These active algicidal substances made of conjugation unsatuated bonds, hydroxyl, saturated alkyl and aromatic ethers. In the three-dimensional fluorescence spectroscopy, two strong fluorescence peaks appear at 264/436 nm and 378/369 nm respectively. Mass spectrum indicates that the active substances consist of six monomers, and their molecular weights are 163.1, 246.3, 274.3, 318.3, 404.5 and 475.4, respectively.