理化因子对谷皮菱形藻细胞密度及中性脂含量的影响

以高脂微藻谷皮菱形藻(Nitzschia palea NY025)为实验材料,探讨了利用光密度法和尼罗红荧光染色法测定细胞生长和细胞中性脂含量的可行性,进而研究了温度、光强及培养基中N、P、Si含量对藻细胞生长和中性脂积累的影响。结果表明:(1)谷皮菱形藻在675nm处存在最大吸收峰,细胞密度与OD675之间存在良好的线性关系,利用光密度法和尼罗红荧光染色法表征谷皮菱形藻生物量和中性脂含量操作简单,适用于高通量样品的测定;(2)谷皮菱形藻在20℃,光强160μmol m-2s-1时生长最快,在20℃,光强200μmol m-2s-1时,有利于中性脂积累;(3)培养基中N、P、Si浓度分别为80、120、100 mg/L时,有利于谷皮菱形藻细胞生长,其中,N元素影响最大,其次是P、Si,且N、P、Si三因子以及交互作用N×P与P×Si对藻株生长作用均为显著。培养基中N、P、Si浓度分别为80、120、50 mg/L时,利于中性脂积累,其中,N元素影响最大,其次是Si、P,且因子N、Si及交互作用N×P、N×Si作用均为显著;(4)可采用两步培养法,先使谷皮菱形藻细胞大量增殖,而后适当改变培养条件,以增加脂质合成。     

谷皮菱形藻的耐盐适应性

本文报道了在水产养殖上有较大经济价值的硅藻代表种类——谷皮菱形藻对盐度的适应性。该藻有较强的耐盐适应性,在含≤1.0mol/L NaCl的培养基中均能生长,其最适生长盐度约为18‰(含0.25 mol/L NaCl的培养基)。在不同盐度下生长的细胞中其主要生化组分含量有不同程度的改变。类胡萝卜素/叶绿素的比值随盐度的增加略有升高,这主要是由于叶绿素含量随盐度增高而降低所致;细胞蛋白质含量与盐度改变无明显关系;但糖类却随盐度提高而成倍增加,表明糖类是谷皮菱形藻适应盐度改变的主要渗透调节物。同时,在较高盐度时,谷皮菱形藻细胞内氨基酸含量明显增加,显示一些氨基酸特别是脯氨酸在谷皮菱形藻耐盐适应过程中也起着相当的渗透调节作用。     

丹江口水库一株硅藻的分子鉴定及氮素对其生长的影响

采用稀释分离法和小液滴分离法, 从丹江口水库水样中分离了一株硅藻。通过形态学观察和18S rDNA、SSU rDNA、rbcL的序列分析, 将其鉴定为谷皮菱形藻。以NaNO3、NH4Cl和尿素为氮源, 研究了不同氮素对其生长特性的影响。结果表明, 谷皮菱形藻在铵态氮、硝态氮和有机氮中均可正常生长, 但生长特性对不同氮素形态的响应有所不同。在NaNO3和尿素的培养条件下, 谷皮菱形藻的生长速率随氮素浓度的增加而相应增加, 而在NH4Cl培养基中, 生长速率随氮素浓度的增加表现出先增加后降低的趋势。在NH4Cl 350 μmol·L-1时达到最高, 最大比生长速率和细胞密度分别为0.2920 d-1和189×104 个·mL-1, 表明高浓度铵态氮对其生长有抑制作用。本研究可为谷皮菱形藻的分子鉴定提供依据, 也可为保护丹江口水库的水质安全提供基础资料。     

生态因素对海洋微藻蛋白质含量的影响

考察了光照时间,培养温度,二氧化碳通入量等生态因素对处于不同生长时期的小球藻,等鞭金藻,新月菱形藻中的蛋白质含量的影响。结果表明,不同种类的微藻,生态因素对其胞内蛋白质含量的影响不同,小球藻在光照17h,培养温度19℃,每日间歇通入25mLCO2/L培养液的条件下,培养至对数对数生长期,蛋白质含量达到70%;等鞭金藻在光照17h,培养温度19℃以上,不通入CO2的条件下培养至静止期,蛋白质含量接近70%;新月菱形藻光照17h,培养温度25℃,不通入CO2的条件下培养至对数对数生长期,蛋白质含量超过70%。     

温度和初始密度比对2种微藻生长竞争的影响研究

为了探究不同温度和初始密度比对舟形藻和铜绿微囊藻生长竞争的影响,该研究设计不同温度梯度(10、15、20、25、30和35℃)和舟形藻与铜绿微囊藻不同初始密度比(1∶10、1∶1、10∶1),研究不同条件对2种微藻生长竞争的影响。结果表明:(1)单种培养条件下,随温度升高,舟形藻细胞密度呈现先增后减趋势,最适生长温度为20～25℃,最大藻细胞密度为3.883×10~5个/mL;铜绿微囊藻细胞密度随温度升高而增大,35℃达到最大值(4.813×10~6个/mL)。(2)混合培养条件下,温度和初始密度比对两者生长均产生影响,舟形藻对铜绿微囊藻的竞争能力随舟形藻初始密度增大而增强,温度25℃、初始密度比10∶1处理条件下,舟形藻对铜绿微囊藻生长抑制作用最为明显。(3)根据Lotka-Volterra竞争模型推断,高温(30～35℃)条件下,铜绿微囊藻占有优势;低温(10～20℃)条件、初始密度比为1∶10的舟形藻与铜绿微囊藻稳定共存;初始密度比为1∶1和10∶1时舟形藻占有优势,且在舟形藻最适生长条件(25℃)下两者不稳定共存。     

不同温度对念珠藻生理生化特性的影响

文章尝试比较不同温度对念珠藻（Nostocsp.）细胞生长和生理特性的影响。主要内容是分别在10℃、25℃、35℃和40℃环境中对念珠藻进行9 d的室内培养，然后测定不同温度下念珠藻的生物量、光合活性、总多糖、总蛋白质和总脂质含量。研究结果表明，低温（10℃）对念珠藻细胞生长的促进与光合活性的提高基本无影响；而高温（35℃、40℃）会促进藻细胞的生长和光合活性的提升。也就是说，低温时念珠藻细胞的多糖含量几乎不变，蛋白质含量与脂质含量先升高后降低；而高温时多糖含量和蛋白质含量增加，脂质含量降低。以上结果说明温度胁迫会使念珠藻对生物大分子物质进行调控用于抵抗环境变化。     

氮、磷对小新月菱形藻无机碳利用与碳酸酐酶活性的影响

在实验室条件下研究了氮磷浓度变化对小新月菱形藻无机碳利用与碳酸酐酶活性的影响,结果显示小新月菱形藻随培养液中氮、磷浓度的升高比生长速率明显提高。低氮浓度导致胞外碳酸酐酶活性丧失,但胞内碳酸酐酶活性依然存在。高氮浓度下胞内、外碳酸酐酶活性均明显升高。胞内碳酸酐酶活性在高磷浓度下明显升高,但胞外碳酸酐酶活性并没有受到磷浓度变化的影响。高氮、磷浓度培养下的小新月菱形藻的最大光合作用速率(Vmax)、对CO2亲和力(K0.5(CO2))和光系统II最大光化学效率(Fv/Fm)均明显提高。以上结果表明小新月菱形藻可以通过改变胞内、外碳酸酐酶活性调节无机碳利用以适应不同氮磷浓度的环境。     

小球藻的优化培养及胞内多糖的提取

小球藻细胞中所含有的多糖和糖蛋白等活性物质具有明显的抗肿瘤,抗病毒感染及增强机体免疫力等作用。首先考察了几个重要的环境因素对小球藻生长及胞内多糖含量的影响。确定了优化的环境条件为：光照17h,培养温度15℃,营养盐KNO3浓度为2mmol/L。在此优化条件下,大批量培养小球藻至平衡期,离心收集藻细胞,再经过冻融与超声波破碎,三氯乙酸沉淀蛋白质,最后通过SephadexG-75凝胶柱分离得到了两种分子量不同的多糖,并结合醋酸纤维素膜电泳证明了同样的结论。     

温度和光照强度对鼠尾藻生长和生化组成的影响

在实验室条件下,研究了温度(10、15、20、25 ℃)和光照强度(20、60、100、140、180 μE·m^-2·s^-1)对鼠尾藻生长和生化组成的影响.结果表明,温度、光照强度及两者的交互作用对鼠尾藻生长均具有极显著影响.鼠尾藻在15 ℃和20 ℃下生长速率较高,随着温度的升高,达到最大生长速率所需要的光照强度有上升趋势.在10 ℃和15 ℃下,较高的光照强度对鼠尾藻生长产生了一定抑制作用,而在20 ℃和25 ℃下,其生长速率总体随光照强度的增加而增加.温度和光照强度对鼠尾藻叶绿素a、墨角藻黄素的含量影响极显著,其中光照强度的影响大于温度.总体上,叶绿素a和墨角藻黄素的含量均随着光照强度的升高而显著下降,随着温度的升高而升高.鼠尾藻碳水化合物含量随着光照强度的升高而显著升高,而温度对碳水化合物含量影响不显著.鼠尾藻蛋白质含量随着光照强度的增加而显著下降,在10 ℃和15 ℃下含量较高,随着温度的继续升高,蛋白质含量呈下降趋势.光照强度和温度的变化可改变鼠尾藻的藻体成分含量,这种改变可能是鼠尾藻为了适应环境因子改变而做出的积极的生理调节,对其生长和生存具有重要的生态意义.     

不同培养条件对海洋微藻多糖含量的影响

通过对不同培养条件下四种海洋微藻胞内多糖含量的测定,系统地研究了光照时间、温度、ＣＯ２的通入量及营养盐对微藻胞内多糖的影响,以探索其优化条件。     

The influence of photon flux density (PFD) on short term 14C incorporation into proteins,carbohydrates and lipids in freshwater algae

The effect of photon flux density (PFD) on the partitioning of photosynthetically fixed ¹⁴CO₂-C into major intracellular end products was investigated for three species of freshwater planktonic algae (Nitzschia palea, Monoraphidium minutum and Synechococcus elongatus belonging to three different classes. This study was designed to investigate the phenomenon of polysaccharide synthesis associated with the saturation of protein synthesis and to test if this process is common to all three phytoplankton species. Protein synthesis was saturated at low PFD in all three species of algae studied. However, fixed carbon was differentially stored, namely in lipids in Nitzschia palea (Bacillariophyceae), in polysaccharides in Monoraphidium minutum (Chlorophyceae), and in low molecular weight metabolites (LMW) in Synechococcus elongatus (Cyanophyceae). The results of this transient state study indicate that the metabolic pathways of algae can easily be controlled by different irradiance. Furthermore, it appears that the difference in the patterns of synthesis is taxonomy dependent.     

Effects of Temperature on the Growth and Physiological Characteristics of Dendrobium officinale (Orchidaceae)

In this paper, we studied the response of photosynthesis and growth in Dendrobium officinale to temperature under the control experiment to provide a theoretical basis for its cultivation. Temperature had a significant effect on the photosynthetic rate (Pn) of Dofficinale. The light saturated photosynthesis at ambient CO2 concentration (Pmax) of the plants were highest at 30℃. High photosynthetic rate at 30℃ were related to the more balance between the maximum rate of electron transport and maximum rate of RuBP mediated carboxylation. Moreover temperature also showed a significant effect on the growth and polysaccharide content of D.officinale′s stem. The polysaccharide content of Dofficinale at 20℃ was significantly higher than that at other temperatures, while the stem length, stem node number, stem fresh weight and stem dry weight were achieved the highest point at 30℃. The results showed that, the temperature of 30℃ was more appropriate for the photosynthesis of Dofficinale, while the plants at 20℃ have higher polysaccharide content.     

硅藻变温发酵生产二十碳五烯酸的研究

本文考察不了同温度（10℃～30℃）对硅藻(Nitzschia laevis)合成二十碳五烯酸(EPA)的影响,对不同温度下的发酵过程进行动力学特性分析。在此基础上,提出了EPA合成的变温培养方法：延滞期及对数期初期温度控制在25℃,从对数期中期开始在20℃条件下进行培养。采用此变温培养进行发酵,EPA的含量和产量分别达到了6.00%和291.60 mg·L-1,较采用单一温度(25℃)发酵的最大值分别提高了24.07%和18.81%。     

温度对铁皮石斛生长及生理特性的影响

通过不同温度下的控制实验,研究了铁皮石斛光合作用与生长对温度的响应,以期为铁皮石斛的栽培提供理论依据。温度对铁皮石斛的光合速率（Pn）有明显影响,30℃处理的植株具有最高的饱和光合速率（Pmax）,其较高的光合速率与RuBP电子传递速率与羧化速率间相对平衡有关。温度对铁皮石斛茎的生长及多糖含量有明显影响,20℃处理的石斛多糖含量显著性的高于其他两个处理,而茎长、茎节数、茎鲜重等则是在30℃下最高。结果表明,30℃的温度对铁皮石斛的光合作用较为适宜,但在20℃条件下植株具有更高的多糖含量。     

EFFECTS OF ENVIRONMENTAL CONDITIONS ON GROWTH AND LIPID ACCUMULATION IN NITZSCHIA COMMUNIS (BACILLARIOPHYCEAE)

Microalgae from natural saline habitats in the southwestern United States were isolated and screened for rapid growth potential and ability to store intracellular neutral lipid, a precursor for renewable liquid fuel sources. After preliminary screening of isolated strains, Nitzschia communis (Rabenhorst) was selected for optimization of growth rate and lipid yield. Nitzschia communis was subjected to two media types (SERI I, II) with different major ion compositions designed to mimic natural saline groundwater aquifers in the arid Southwest. Growth rates were determined through 4 days of logarithmic growth, followed by 2 days of physiological stress (nitrogen deprivation) and subsequent measurement of neutral lipid accumulation. Poststress intracellular neutral lipid increases were documented by utilizing the fluorochrome Nile Red with fluorometric analysis and epifluorescent microscopy. Growth rate was slightly higher in SERI Type I medium, whereas lipid yield was higher in SERI Type II medium. Rapid growth and appreciable lipid yields were observed over a broad range of temperatures (20°–30° C) and specific conductances (10–70 mS·cm⁻¹). The highest lipid yields were observed at elevated conductances (between 40 mS·cm⁻¹ and 70 mS·cm⁻¹). Substitution of individual salt concentrations from SERI Type II into SERI Type I medium indicated that increased lipid yield in Type I medium was associated with a reduction in MgCl₂ concentration.     

Life Cycle of Nitzschia palea (Kützing) W. Smith (Bacillariophyta)

Russian Journal of Developmental Biology - The diatom Nitzschia palea is a widespread eurybiontic alga that inhabits the benthos of freshwater ponds and watercourses, soils and caves. This species...     

THE ACCLIMATED RESPONSE OF GROWTH,PHOTOSYNTHESIS, COMPOSITION,AND CARBON BALANCE TO TEMPERATURE IN THE PSYCHROPHILIC ICE DIATOM NITZSCHIA SERIATA1

Nitzschia seriata Cleve, a common member of marine bottom ice communities in the Arctic, was grown in unialgal batch cultures to test for compensatory mechanisms for the low temperatures (?1.8° C) typical of its natural habitat. The upper lethal limit for growth was between 12° and 15°C, and the optimum was between 6° and 12° C. The Arrhenius function adequately (R²= 73%) fitted the relationship between growth rate and temperature from – 1.6° up to 10° C, with an average Q₁₀ of 1.9 over the entire range. Light-saturated and light-limited rates of photosynthesis (normalized to chlorophyll a or cell carbon) showed complete compensation from 12° to 4° C. Photosynthetic rates, especially at light saturation, declined rapidly at temperatures below 4° C. Susceptibility to photoinhibition was greatest at the lowest growth temperatures. Cellular composition (chlorophyll a, protein, polysaccharide, and lipid contents) was not systematically related to temperature in any simple way, although cell size (carbon per cell) was maximal at the lowest growth temperature. Dark respiration was unmeasurably low (<0.015 day^?1) at all growth temperatures. The strategy of adaptation in N. seriata may be characterized as optimizing efficiency and compensation, rather than maximization, of growth rate.     

Survival and motility of diatoms<Emphasis Type="Italic">Navicula grimmei</Emphasis> and<Emphasis Type="Italic">Nitzschia palea</Emphasis> affected by some physical and chemical factors

Navicula grimmei and Nitzschia palea occurring almost equally in a mixed population on department moist garden soil surface when maintained in fresh supernatant (of soil-water medium) at pH 7.0, temperature of 26 +/- 1 degree C and under continuous light (intensity of approximately equal to 30 micromol m(-2) s(-1)) in a culture chamber exhibited a similar cell survival period (of 28 d) and percentage (at the beginning 100 % and mid of survival period 65 %) and stop gliding 11 d prior to cell death (with gliding speed reduced in both from 204-330 microm/min at the beginning to 82.5-99 microm/min at the mid of gliding period) irrespective of their size differences. However, a sharp fall in the cell gliding period, gliding cell percentage and speed occurred at various levels (different from cell survival period and percentage) in both diatoms in a similar extent under water stress (2, 4 and 6 % agarized supernatant, liquid supernatant with 0.2-1.0 mol/L NaCl, blot-dryness of cells for 5-15 min), pH extreme of liquid supernatant (< or =5.0, > or =9.0), temperature extremes in liquid supernatant (< or =15, > or =40 degrees C), UV exposure (0.96-5.76 kJ/m2), lack of all nutrients from the medium (double distilled water), darkness or low light intensities (2 and 10 micromol m(-2) s(-1)), presence of 'heavy' metals (Ni, Cu, Zn, Co, Fe, Hg; 1-200 ppm), organic substances in liquid supernatant (DDT, captan, urea, 2,4-D, 100-2000 ppm; thiourea, 50-1000 ppm). N. palea sway (turn around at either ends) or not only when gliding but independent of cell gliding speed, which decreased continuously under all conditions.     

Effects of enhanced ultraviolet-B radiation on the production of lipid, polysaccharide and protein in three freshwater algal species

1. The effects of ultraviolet-B (UVB-enhanced) radiation on the production of photosynthates (lipid, protein, polysaccharide and low molecular weight compounds) was examined for three species of algae. Cryptomonas sp., Nitzschia palea and Synechococcus elongatus were selected as representatives of the Cryptophyceae, Bacilliarophyceae and Cyanobacteria, respectively.
2. Laboratory experiments were performed at several UVB_weighted dose rates ranging from 0.018 to 0.391 mW cm^–2. These dose rates span the range of dose rates used in other studies.
3. Effects on the overall photosynthetic rate were observed, even at relatively low UVB_weighted dose rates (0.047 mW cm^–2).
4. The effect of UVB radiation on the fixation of carbon into the main macromolecular pools differed, depending not only on the dosage but on the species examined. However, the observed inhibitory effects were generally non-stochastic. In addition, within each species there were differences in the apparent sensitivity of the various fractions to inhibition by UVB radiation.
5. These results suggest that exposure to UVB radiation has the potential to alter the relative allocation of recently fixed carbon to lipid, protein, polysaccharide and low molecular weight compounds in algae in a species-specific manner.