Assessment of Bioactive Potential of Aqueous Protein Extracts from Diatoms Nitzschia laevis,Spirulina platensis,and Chlorella vulgaris

The bioactivities of protein extracts from Nitzschia laevis, Spirulina platensis, and Chlorella vulgaris were evaluated in vitro. Free radical scavenging potential, reducing power, oxygen radical absorbance capacity, superoxide anion radical, xanthine oxidase inhibition, and potential to inhibit angiotensin 1-converting enzyme (ACE) and acetylcholinesterase enzyme (AChE) were studied. Nitzschia protein extracts showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, reducing power, and ACE inhibitory activity. Spirulina’s proteins showed the highest 2,2′-Azino-bis (3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, xanthine oxidase, and AChE inhibition activities. Aqueous protein extracts from Nitzschia, Spirulina, and Chlorella showed in vitro antioxidant, anti-ACE, and anti-AChE activities, suggesting possible new sources of bioactive proteins of different phyla with nutraceutical and pharmaceutical potentials.     

生长阶段及温度对微藻细胞总ATP酶活性的影响

以亚心形扁藻(Platymonas subcordiformis)、大溪地球等鞭藻(Isochrysis galbana daxidi)和小新月菱形藻(Nitzschia closterium)为实验对象,探讨批次培养过程中不同生长阶段及不同温度处理的藻细胞总ATP酶活性.结果表明:三种微藻在不同生长阶段的细胞总ATP...     

新月菱形藻的光生物反应器半连续培养

利用平板式光生物反应器对新月菱形藻进行半连续培养,探讨更新率、更新周期对新月菱形藻生长、细胞采收量、生化成分及细胞生物量产率的影响.结果显示,随更新率的增大,新月菱形藻的生长速率增大,藻液中氮磷的平均含量上升,而平均细胞密度及产率呈下降趋势;总采收量与更新率呈抛物线关系,细胞生物量、胞内多糖和蛋白的最大采收量分别收获于33%、25.2% 和34.7%的更新率下,其最大值分别为2.11×1012 cell、3623 mg 和2347 mg.更新周期的延长导致新月菱形藻平均生长速率减小,藻液中氮磷的平均含量下降,而采收的平均细胞密度与产率增大,胞内代谢物蛋白质和多糖的含量增加;总细胞采收量随着更新周期的延长减小,当更新周期为1 d时采收量最大,为3.12×1012 cell.综合考虑,更新率为33%、更新周期为1 d,是收获生物量的最佳条件.     

四种微藻对氨苄青霉素敏感性的研究

海洋微藻培养中抗生素的大量使用对微藻的生长产生一定的影响。为了研究抗生素在海洋微藻培养过程中对微藻的影响,本文探讨了四种海洋微藻(海链藻、小硅藻、塔胞藻、小球藻)对氨苄青霉素的敏感性,通过培养过程中加入抗生素进行培养并测定其光密度值进行试验。研究表明,氨苄青霉素对海链藻的生长影响较大,对其它的三种微藻影响较小。     

Influence of Nitzschia sp. on release of nitrogen and phosphorus from sediment in pond breeding sea cucumbers

Due to the tonic and nutritive virtues of sea cucumbers, increased commercial aquaculture has resulted in the expansion of breeding ponds, a primary form of sea cucumber production. Expansion of such production methods has led to increased settling of organic wastes onto the seabed, resulting in enriched sediments. Nitzschia sp. serves as an edible sea cucumber feed. Release characteristics of nitrogen (N) and phosphorus (P) from sediments in the presence of different biomass densities of Nitzschia sp. were studied via laboratory static cultures. pH and dissolved oxygen (DO) in the overlying water and biochemical components (i.e., protein, chlorophyll a) of Nitzschia sp. were assessed. When the biomass of Nitzschia sp. was more than (2–5) × 10⁴ ind/cm², the release of N and P nutrients was significantly promoted; additionally, the DO content of the overlying water was relatively high and the pH was relatively stable, which favoured the accumulation of proteins and chlorophyll a in Nitzschia sp. The results indicated that Nitzschia sp. promotes the release of N and P in sediments while absorbing them to maintain their own growth and promote the accumulation of nutrients, such as proteins, for the sea cucumbers. At the same time, the algae release oxygen, increasing the DO of the overlying water, providing a healthy breeding environment for the sea cucumbers. Application of Nitzschia sp. has the potential to reduce environmental harm caused by sea cucumber cultivation and thus achieve sustainable aquaculture.     

小头端菱形藻生长的最适光照强度及氮磷比

[目的]为进一步探索小头端菱形藻（Nitzschia capitellata Hust．）作为优质饵料、生物能源的潜能,在室内条件下对小头端菱形藻生长的最适光照强度、氮磷比等培养条件进行研究。[方法]首先设定不同光照度梯度,在相同营养、温度（25±1）℃以及光周期（12h／12d）下进行培养,筛选得出最适光照强度,其次将氮磷比设置为5：1、6：1、7：1和8：1,置于相同条件进行培养。[结果]在3000lx的光照度下,小头端菱形藻的藻比增殖率和现存量最高,分别为0．51d。和7．97×10^4cells／ml。在氮磷比为6：1条件下,小头端菱形藻生长最佳。[结论]小头端菱形藻的最适光照度为3030lx,最适氮磷比为6：1。     

Cd（Ⅱ）、Zn（Ⅱ）对新月菱形藻生长及生化成分的影响

研究了不同浓度的Cd（Ⅱ）、Zn（Ⅱ）对新月菱形藻Nitzschia closterium生长及细胞内蛋白质、多糖、叶绿素等生化成分含量的影响。结果表明：新月菱形藻对两种重金属均有一定的耐受力;Cd（Ⅱ）、Zn（Ⅱ）浓度分别低于3.0、1.0 mg/L时对新月菱形藻的生长没有显著影响（P〉0.05）,高于此浓度则产生明显的抑制作用（P〈0.05）;Zn（Ⅱ）对新月菱形藻胞内蛋白质含量的影响不明显（P〉0.05）,Cd（Ⅱ）能抑制新月菱形藻蛋白质的合成;低于3.0 mg/L的Cd（Ⅱ）、Zn（Ⅱ）能促进新月菱形藻胞内多糖和叶绿素的合成。     

小新月菱形藻碳酸酐酶活性和光合作用对高盐度胁迫的响应

以浮游硅藻小新月菱形藻为实验材料,研究其在不同盐度下的生长、胞外碳酸酐酶活性、光合速率和叶绿素a荧光参数的变化。结果显示,与正常海水培养相比,最高盐度(70)培养的细胞比生长速率下降了59.2%;同时,胞外碳酸酐酶活性、叶绿素a、c含量分别降低了66.3%、50.0%和45.7%。高盐度培养下,最大光合速率(P_{m)、光合效率(α)、最大光化学效率(Fv/Fm)、实际光化学效率(Yield)和光化学淬灭系数(qP)下降,但非光化学淬灭系数(qN)升高,对无机碳的亲和力明显下降。以上结果表明,盐度升高对小新月菱形藻生长和光合作用具有明显抑制作用,但小新月菱形藻可以通过胞外碳酸酐酶活性变化、对无机碳的亲和力和调整光系统Ⅱ的能量流动与能量利用效率以应对高盐度的胁迫。}     

N/P对菱形藻生长速率和营养成分含量的影响

研究了N/P(1∶1、5∶1、12.5∶1、30∶1、50∶1、80∶1)对菱形藻的生长速率、营养成分含量及氮磷利用率的影响。试验结果表明,(1)N/P对菱形藻的生长影响显著(P0.05),其中N/P为12.5∶1时,比生长速率最大,当N/P5∶1和N/P50∶1时,菱形藻的生长较慢,比生长速率为0.3～0.6/d;(2)藻细胞营养成分的含量也受N/P的影响:在N/P为12.5∶1时,叶绿素的含量达到1.81g/ml,总脂肪、蛋白质、胞外多糖和胞内多糖的含量分别占干质量的29.9%、17.8%、15.3%、14.2%,高于其他N/P下的营养成分含量;(3)培养后水体中氮磷的含量明显下降,TN的利用率之间有显著性差异(P0.05),利用率均超过55%,最高为30∶1,达78%,TP的利用率之间无显著性差异(P0.05),均高于90%。     

Optimal Light Intensity and Nitrogen-to- Phosphorus Ratio for Growth of Nitzschia capitellata Hust,

[目的]为进一步探索小头端菱形藻（Nitzschia capitellata Hust.）作为优质饵料、生物能源的潜能,在室内条件下对小头端菱形藻生长的最适光照强度、氮磷比等培养条件进行研究。[方法]设定不同光照度梯度,在相同营养、温度（25±1）℃以及光周期（12 h/12 d）下进行培养,筛选得出最适光照强度,其次将氮磷比设置为5∶1、6∶1、7∶1和8∶1,置于相同条件进行培养。[结果]在3000 lx的光照度下,小头端菱形藻的藻比增殖率和现存量最高,分别为0.51 d-1和7.97×104 cells/ml。在氮磷比为6∶1条件下,小头端菱形藻生长最佳。[结论]小头端菱形藻的最适光照度为3000 lx,最适氮磷比为6∶1。