紊流扰动对水华鱼腥藻细胞生理的影响

正三峡水库成库以来,支流回水区频繁出现水华现象,成为近10年来我国水库生态学领域研究热点~([1])。水流条件是水华形成的主要诱导因素之一~([2]),合适的流速条件能给藻类生长营造有利的外部环境~([3])。温度、光照和营养盐是影响藻类生长的重要环境因子,在自然水体中随着深度的变化而变化~([4])。普遍认为,紊流扰动通过改变藻类在水体中的相对位置和分布,从而改变藻类生长的     

溶藻细菌L7对水华鱼腥藻氮代谢的影响

【目的】进一步探明藻菌关系,研究溶藻细菌对藻类氮代谢的影响及其作用机制。【方法】将水华鱼腥藻和溶藻细菌L7按两种比例接种入BG11培养液中,在室内进行共培养(藻细胞初始密度为1.21×108cells/L;溶藻细菌L7初始密度分别为1.75×107、1.75×108CFU/mL)。连续7 d测定藻细胞数、异形胞频率和藻细胞内的硝酸还原酶(NR)活性、谷氨酰胺合成酶(GS)活性、谷氨酸合成酶(GOGAT)活性、蛋白质含量、丙二醛(MDA)含量。【结果】低密度溶藻细菌L7能够促进藻生长(第7天藻细胞密度是对照组的1.58倍),增加异形胞频率(第7天高于对照组66.67%);高密度则会抑制藻生长(第7天藻细胞密度相比对照组下降98.84%),降低异形胞频率(第7天为0)。在藻细胞内氮代谢关键酶活性方面,接种后2 5 d,两处理组中藻细胞内NR和GOGAT活性均极显著高于对照组(P<0.01);接种后0 5 d,高密度处理组的GS活性极显著高于对照组(P<0.01),而低密度处理组的则在大部分时间内极显著低于对照组(P<0.01)。在整个实验期内,低密度处理组中藻细胞内蛋白质含量一直极显著高于对照组(P<0.01);而在高密度处理组中,除第5天外,细胞内蛋白质含量则全部极显著低于对照组(P<0.01)。接种后2 4 d,高密度处理组中藻细胞内MDA含量呈现上升趋势,并极显著高于其余两组(P<0.01)。【结论】低密度溶藻细菌L7能够提高水华鱼腥藻对氮源的需求,加速蛋白质合成,促进氮代谢;而高密度溶藻细菌L7会对藻细胞产生过氧化伤害,阻碍蛋白质合成和氮代谢过程。     

亚硫酸氢钠对鱼腥藻生长的影响

在不同条件下研究了光呼吸抑制剂——亚硫酸氢钠对鱼腥藻(Anabaena)生长的影响。结果表明亚硫酸氢钠的浓度在1—10μg/ml时都提高了鱼腥藻的生物量,浓度在2.5和5.0μg/ml的效果优于其他浓度。亚硫酸氢钠提高了鱼腥藻叶绿素a的含量,但是,对蛋白质的含量没有的影响。亚硫酸氢钠用于增加鱼腥藻生物产量是有意义的。     

水华鱼腥藻生长与光合作用对大气CO2浓度升高的响应

 为了探讨大气CO2浓度升高对水华藻类的影响,利用水华鱼腥藻(Anabena flos_aquae)作为实验材料,研究了大气CO2浓度加倍对其生长和光合作用的影响,结果显示大气CO2浓度升高导致水华鱼腥藻的生物量、光饱和光合速率、光合效率和光系统II的光化学效率（Fv/Fm）明显提高,但对暗呼吸速率和光饱和点没有明显影响。CO2加倍条件下藻细胞光合作用对无机碳的亲和力降低,表明其利用HCO-3的能力受到抑制。     

水杨酸对水华鱼腥藻的化感抑制作用及相关毒理学的初步研究

研究了不同浓度的水杨酸时水华鱼腥藻生长的影响以及对鲤鱼的毒性作用.结果表明,一定浓度的水杨酸能有效抑制水华鱼腥藻的生长;抑藻作用的最佳浓度为0.6 mmol/L,用该浓度的水杨酸溶液处理鲤鱼1周后,鲤鱼血清中的天门冬氨酸氡基转移酶(AST)、丙氨酸氨基转移酶(ALT)、γ-谷氨酰基转移酶(GGT)、碱性磷酸酶(ALP)的活性没有明显影响,对肝脏、鳃和肌肉中的超氧化物歧化酶(SOD)及膜脂过氧化产物(MDA)的活性也没有明显影响,提示水杨酸时鲤鱼无毒性作用,时水华治理有一定的应用前景.     

春季东海中华哲水蚤对有害藻华物种的选择性摄食

2005年4月27日—6月5日在东海有害藻华高发区的6个典型站位采样,分析了浮游植物的群落结构,并采用现场实验研究了中华哲水蚤(Calanus sinicus)的选择性摄食.结果表明,中华哲水蚤对浮游植物的选择性摄食具有食物密度依赖性.低浮游植物细胞丰度下中华哲水蚤具有明显的选择性摄食行为,高浮游植物细胞丰度下中华哲水蚤摄食选择性由偏好转变为排斥,浮游植物细胞丰度329 cells·ml^-1是中华哲水蚤由偏好趋于排斥摄食的阈值.中华哲水蚤的选择性摄食还与食物组成有关,对于食物中的微型浮游动物,中华哲水蚤无选择性或排斥摄食.有害藻华发生区中华哲水蚤对具齿原甲藻(Prorocentrum dentatum)的偏好摄食以及对米氏凯伦藻(Karenia mikimotoi)的排斥摄食,促使藻华的物种演替最终向米氏凯伦藻水华方向发展.     

pH值对转基因鱼腥藻培养的影响

研究pH值对转基因鱼腥藻培养的影响,发现培养基初始pH以自然pH8.3为宜,间歇流加稀盐酸控制过程pH值为8.5和9.0,生长较未流加快,每天流加稀盐酸一次控制过程pH为8.5,15d生物量大于3g/L,可溶性蛋白为0.3g/l藻干重,TNF表达量超过22%,生物量比未流加增长12.41%,而TNF表达量未受影响。     

浮丝藻生活史及其亚显微结构特征的研究

通过观察浮丝藻（Ｐｌａｎｋｔｏｎｅｍａ）的生活史、显微和亚显微结构、细胞分裂方式,系统地研究了其藻丝体的生物学特性。浮丝藻为单列细胞不分枝的丝状体,细胞圆柱形或椭圆形,细胞之间主要靠筒状的纤维素细胞壁相互连接。藻细胞中含叶绿素ａ、ｂ和β－胡萝卜素。电镜下,细胞壁明显分层,绝大多数是２～３层;色素体片状、周生,通常２至多条类囊体重叠;１～２个蛋白核在色素体体上,蛋白核外常有淀粉鞘,有时１至多条类囊体重叠;１～２个蛋白核在色素体上,蛋白核外常有淀粉鞘,有时１至多条类囊体侵入蛋白核内;１～２个线粒体位于色素体旁,嵴不分枝;高尔基复合体靠近细胞周边,分泌许多潴泡;细胞核１个,球形或不规则方形,常靠近细胞的一端;光镜下细胞两端的折光亮点在电镜下是１至多个泡囊,泡囊内通常含些被染色很深的物质。浮丝藻的形态学、细胞分裂和生活史观察结果都证明,浮丝藻的细胞在整个生活史中没有营养分裂,细胞分裂时母细胞产生两个有独立、完整细胞壁的似亲孢子,一系列似亲孢子通过存留的、不连续的筒状或杯状母细胞壁连接成形状上象丝状体的结构。因此,藻丝体形成和成长的过程是一个无性繁殖过程,这样的藻丝体本质上是一种假丝体。     

维生素对转基因鱼腥藻Anabaena sp.PCC7120培养的影响

近年来分子遗传学和基因工程研究证实 ,大肠杆菌的载体和启动子往往可以适用于蓝藻 ,尤其是单细胞蓝藻的转基因 ,这使得蓝藻基因工程得到了较快的发展 ,利用藻类为宿主的基因产物的生产也受到日益关注 ,因此微藻的培养受到广泛重视。刘凤龙等通过三亲结合转移方式将人ＴＮＦ α基因转入鱼腥藻 71 2 0中并得到表达[1 ] ,但转基因鱼腥藻高效培养方面需进一步研究。混合营养培养方式因具有缩短培养周期、实现细胞高密度培养等优点 ,已成为微藻培养新技术。藻类生长除了需要合适的营养源外 ,许多生长因子对生长具有较大影响 ,本文对维生素Ｂ1 、…     

EFFECT OF SODIUM AND NITRATE ON GROWTH OF ANABAENA FLOS-AQUAE (CYANOPHYTA)1

The growth response of a nitrogen fixing cyanobacterium, Anabaena flos-aquae (Lyng) Bréb., to sodium and nitrate was examined in batch culture under controlled laboratory conditions. Sodium (range 0-12 mg Na⁺· L^-1) enhanced growth of the cyanobacterium under nitrate-sufficient (5.7 mg NO³-N · L^-1) but not nitrate-limited (0.49 mg NO³- N · L^-1) conditions. The magnitude of the growth response was related to the nutritional history of the culture. No significant effect of sodium on nitrate utilization was observed. The increase in ambient sodium levels in many lakes may provide a competitive advantage to cyanobacteria.     

KINETICS OF GROWTH AND DEATH IN ANABAENA FLOS-AQUAE (CYANOBACTERIA) UNDER LIGHT LIMITATION AND SUPERSATURATION

The kinetics of population growth and death were investigated in Anabaena flos-aquae (Lyngb.) Bréb grown at light intensities ranging from limitation to photoinhibition (5 W·m⁻² to 160 W·m⁻²) in a nutrient-replete turbidostat. Steady-state growth rate (μ, or dilution rate, D) increased with light intensity from 0.44·day⁻¹ at a light intensity of 5 W·m⁻² to 0.99·day⁻¹ at 20 W·m⁻² and started to decrease above about 22 W·m⁻², reaching 0.56·day⁻¹ at 160 W·m⁻². The Haldane function of enzyme inhibition fit the growth data poorly, largely because of the unusually narrow range of saturation intensity. However, it produced a good fit (P < 0.001) for growth under photoinhibition. Anabaena flos-aquae died at different specific death rates (γ) below and above the saturation intensity. When calculated as the slope of a v_x⁻¹ and D⁻¹ plot, where v_x and D are cell viability (or live cell fraction) and dilution rate, respectively; γ was 0.047·day⁻¹ in the range of light limitation and 0.103·day⁻¹ under photoinhibition. Live vegetative cells and heterocysts, either in numbers or as a percentage of the total cells, showed a peak at the saturation intensity and decreased at lower and higher intensities. The ratio of live heterocysts to live vegetative cells increased with intensity when light was limiting but decreased when light was supersaturating. In cells growing at the same growth rate, the ratio was significantly lower under light inhibition than under subsaturation and the cell N:C ratio was also lower under inhibition. The steady-state rate of dissolved organic carbon (DOC) production increased with light intensity. However, its production as a percentage of the total C fixation was lowest at the optimum intensity and increased as the irradiance decreased or increased. The rate and percentage was significantly higher under photoinhibition than limitation in cells growing at the same growth rate. About 22% of the total fixed carbon was released as DOC at the highest light intensity. No correlation was found between the number of dead cells and DOC.     

鱼腥藻提取液对水稻生长发育和产量的促进作用

以田间小区试验和大区产量直接对比的方法研究了鱼腥藻提取认对水稻幼苗生长和产量以及产量构成要素的影响,并探讨了方便有效且适宜于大田使用的方法。用藻液处理后水稻幼苗增高,根数、根长增加,分蘖能力增强,秧龄提前,叶面积明显加大。水稻成熟后除株高比对照略有下降外,各项产量构成要素如粒数、粒重、有效分蘖数、植株干重、千粒重、穗长等都优于对照组,但增产幅度随水稻品种和处理方式不同而异。大田使用时以１％鱼腥藻提     

DYNAMICS OF CELLULAR AND EXTRACELLULAR cAMP IN ANABAENA FLOS-AQUAE (CYANOPHYTA): INTRINSIC CULTURE VARIABILITY AND CORRELATION WITH METABOLIC VARIABLES1

The production and extracellular release of cyclic adenosine 3′: 5′-monophosphate (cAMP) by the blue-green alga Anabaena flos-aquae (Lyngb.) Breb. varied greatly within and between active growth phase and stationary phase and under differing nutrient regimes. Enhanced cellular cAMP production was found in actively growing Anabaena inoculated into media deficient in nitrate or phosphate, or into fresh media containing non-limiting nutrient concentrations. In stationary phase Anabaena, but not actively growing cells, the concentrations of intra-cellular cAMP present in cells grown under a variety of nutrient regimes could be significantly correlated to [¹⁴C]-bicarbonate uptake by an exponential relationship.     

GROWTH RESPONSE OF A NITROGEN FIXER (ANABAENA FLOS-AQUAE,CYANOPHYCEAE) TO LOW NITRATE1

Anabaena flos-aquae (Lyngb.) Bréb. was grown in varying concentrations of nitrate. Specific growth rates, as estimated in batch culture, were constant and approached the maximum rate at all concentrations of NO₃^?-N tested bewteen 0 and 400 μ/L. Steady-state biomass, as determined in semicontinuous culture, did not vary with NO₃^? at slower dilution rates. However at a faster dilution rate, significantly less biomass occurred in intermediate concentrations of NO₃^? than in either higher or lower concentrations. The results indicate that both growth rate and standing crop are maximized by either N₂ fixation or NO₃^? assimilation, but extracellular NO₃^? reduces the rate of N₂ fixation. Consequently, at very low NO₃^? concentrations, growth is virtually maximized by N₂ fixation alone, and at high concentrations of NO₃^?, N₂ fixation is inhibited but growth is maximized by assimilation of NO₃^?. At intermediate concentrations of NO₃^?, growth becomes a function of NO^3? assimilation augmented by N₂ fixation. In this case, full growth potential is realized only if hydraulic residence time is sufficiently long to compensate for the reduced rate of N₂ fixation. Growth rate and standing crop are not diminished in response to the large amount of energy allocated to N₂ fixation. Instead, other cellular processes are probably affected negatively during N₂ fixation.     

KINETICS OF CELL DEATH IN THE CYANOBACTERIUM ANABAENA FLOS-AQUAE AND THE PRODUCTION OF DISSOLVED ORGANIC CARBON1

Kinetics of cell death and the production of dissolved organic carbon (DOC) were investigated in Anabaena flos-aquae (Lyngb.) Bréb grown on three different N sources (N₂nitrate, and ammonium) in a phosphorus (P)-limited chemostat. The fraction of live cells in the total population increased as growth rate increased with decreasing P limitation. Cell death was less in nitrate and ammonium media than in N₂. The specific death rate (γ), when calculated as the slope ofv^?1_x vs. D^?1, where v_xand D are live cell fraction (or cell viability) and dilution rate, respectively, was 0. 0082 day^?1 in N₂and 0.0042 day^?1 in nitrate. The slope of the plot in ammonium culture was not significant; however, the value of the live cell fraction was within the range for the NO^?₃culture. The fraction of live vegetative cells in N₂ culture was constant at all growth rates and the increase in the overall live cell fraction with growth rate was due entirely to an increase in live heterocysts. Live heterocysts comprised 3.5% of the total cells at a growth rate of 0.25 day^?1 and increased to 6.3% at 0.75 day^?1 with the ratio of live heterocysts to live vegetative cells linearly increasing with growth rate. The fraction of live vegetative cells was invariant in nitrate cultures us in N₂cultures. The live heterocysts fraction also increased with growth rate in nitrate cultures, along with the live heterocysts : live vegetative cells ratio, but the level was lower than in N₂cultures. DOC released from dead cells increased inversely with growth rate in N₂from 36.4% of the total DOC at a growth rate of 0.75 day^?1 to 54.15% at 0.25 day^?1. The contribution of cell death to the total DOC production in nitrate and ammonium media was significantly less than that under N₂DOC from dead cells consisted mainly of high-molecular-weight compounds, whereas DOC excreted from live cells was largely of low molecular weight.     

温度对普通小球藻和鱼腥藻生长竞争的影响

通过室内实验研究了不同温度条件下主要水华藻类鱼腥藻(Anabaena sp. strain PCC)和常见淡水藻类普通小球藻(Chlorella vulgaris)的生长和种间竞争, 结果表明在单种培养和共同培养体系中, 普通小球藻的最大藻细胞浓度随着温度的升高而增加; 鱼腥藻生长最适温度为3035℃。温度对藻类种间竞争抑制参数能够产生明显影响, 鱼腥藻在温度为15℃时对普通小球藻的竞争抑制参数最大, 分别是25℃、30℃、35℃时的1.24倍、1.14倍和1.12倍; 而普通小球藻在30℃时对鱼腥藻的竞争抑制参数最大, 分别是15℃、25℃、35℃条件下的4.25倍、2.03倍和1.20倍。在4个试验温度下普通小球藻对鱼腥藻的竞争抑制参数均大于鱼腥藻对普通小球藻的竞争抑制参数。根据Lotka-Volterra竞争模型可推断, 在4个温度条件下, 普通小球藻和鱼腥藻在竞争中不稳定共存。       

SPECTROPHOTOMETRICALLY ASSAYED INHIBITORY EFFECTS OF MERCURIC COMPOUNDS ON ANABAENA FLOS-AQUAE AND ANACYSTIS NIDULANS (CYANOPHYCEAE)1

The growth-related inhibitory effects of mercuric chloride (MC), methylmercuric chloride (MMC) and phenylmercuric acetate (PMA) (each at 1, 10, 10,² 10³ ppb) were measured in Anabaena flos-aquae (Lyng.) Bréb. and Anacystis nidulans (Richt.) Drouet & Daily. Optical density changes of control cultures compared against those of experimental cultures showed that MC was the least inhibitory of the compounds. MMC. was the most inhibitory, producing statistically significant inhibition at a concentration as low as I ppb in Anabaena. PMA was more inhibitory than MC but less than MMC. Effects caused by the mercury compounds included bleaching of individual cells, cell size changes and destruction of whole cells; the degree and extent of these effects depended on the compound and its concentration in the nutrient medium. The high sensitivities of the algae tested suggested the possibility of using them as test organisms in bioassays for mercury.     

鱼腥藻SP.595液泡化原生质球诱导条件的研究

用浓度为0．15mol／L的KNO3、KCl、K2SO4、KH2PO4、K2HPO4、NaNO3、NaCl、Na2SO4、NaH2PO4、Na2HPO4、(NH4)2SO4、MgSO4、CaC12等单盐分别配合0．1％的溶菌酶处理鱼腥藻sp．595(Anabaenasp．595)。经4h,KH2PO4、K2SO4、Na2SO4、NaH2PO4、(NH4)2SO4、MgSO4、CaC12能诱导形成原生质球,但液泡化原生质球极少,而KNO3、NaNO3、NaC1诱导形成少量液泡化原生质球。用相近浓度的双盐,即KNO3和NaC1、KNO3和(NH4)2SO4、NaC1和(NH4)2SO4分别配合0．1％的溶菌酶处理,诱导效果亦不佳。用相近浓度的三盐NaC1、KNO3和(NH4)2SO4及五种盐NaC1、KNO3、(NH4)2SO4、Na2HPO4和KH2PO4分别配合0．1％的溶菌酶处理,诱导原生质球和液泡化原生质球的效果明显提高,液泡化原生质球比例达到66．90％—79．97％。