IAA对孔石莼生长及叶绿素和蛋白质含量的影响

在22℃、40μE·s-1·m-2连续光照培养条件下,研究了植物生长调节物质(IAA)对孔石莼(Ulvapertusa)的生长及叶绿素和蛋白质含量的影响。研究表明,与对照组相比,0.01～10.00mg·L-1IAA对孔石莼的生长及叶绿素和蛋白质含量都有不同程度的影响。随着IAA的质量浓度的增大,实验组藻体的直径以及叶绿素和蛋白质含量都相应增大。并且发现,当IAA的浓度达到1.00mg·L-1时,对孔石莼的促生长作用最佳,且叶绿素和蛋白质的含量达最高值;而当IAA的浓度大于3.00mg·L-1时,对孔石莼的生长却相对抑制,叶绿素和蛋白质的含量也开始降低。

Effects of dietary supplementation of Ulva pertusa and non-starch polysaccharide enzymes on gut microbiota of Siganus canaliculatus

Fishes represent the highest diversity of vertebrates; however, our understanding of the compositions and functions of their gut microbiota is limited. In this study, we provided the first insight into the gut microbiota of the herbivorous fish Siganus canaliculatus by using three molecular ecology techniques based on the 16 S r RNA genes(denaturing gradient gel electrophoresis, clone library construction, and highthroughput Illumina sequencing), and the Illumina sequencing technique is suggested here due to its higher overall coverage of the total 16 S r RNA genes. A core gut microbiota of 29 bacterial groups, covering >99.9% of the total bacterial community, was found to be dominated by Proteobacteria and Firmicutes in fish fed three dif ferent diets with/without the supplementation of U lva pertusa and non-starch polysaccharide(NSP) enzymes(cellulase, xylanase, and β-glucanase). Diverse potential NSP-degrading bacteria and probiotics(e.g., R uminococcus, Clostridium and Lachnospiraceae) were detected in the intestine of the fish fed U. pertusa, suggesting that these microorganisms likely participated in the degradation of NSPs derived from U. pertusa. This study supports our previous conclusion that U. pertusa-based diets are suitable for the production of S. canaliculatus with lower costs without compromising quality.

不同磷酸根含量的孔石莼多糖体外抗氧化活性研究

利用多糖结构修饰原理,制备磷酸化孔石莼(Ulva pertusa)多糖(PU),并对其进行体外抗氧化活性研究。将多聚磷酸钠与三偏磷酸钠混合后作为磷酸化反应试剂,与孔石莼多糖U反应制备不同磷酸根含量的孔石莼多糖PU。通过磷元素含量分析,确定成功制备不同磷酸根含量的孔石莼多糖衍生物PU,并测定不同磷酸根含量的孔石莼多糖PU与孔石莼多糖U对羟自由基、超氧阴离子清除能力以及金属螯合能力。实验发现通过本方法制备得到的PU6磷酸根含量最高为10.47%。综上所述,不同磷酸根含量的孔石莼多糖体外抗氧化活性不同,与孔石莼多糖U相比,磷酸根含量最高的PU6表现出最强的羟自由基清除作用。在100μg/mL多糖浓度下, PU6表现出最强的金属鳌合能力。

De-eutrophication of effluent wastewater from fish aquaculture by using marine green alga Ulva pertusa

The de-eutrophication abilities and characteristics of Ulva pertusa, a marine green alga, were investigated in Qingdao Yihai Hatchery Center from spring to summer in 2005 by analyzing the dynamic changes in NH+4, NOˉ3, NO2ˉ as well as the total dissolved inorganic nitrogen (DIN). The results show that the effluent wastewater produced by fish aquaculture had typical eutrophication levels with an average of 34.3 μmol L-1 DIN. This level far exceeded the level IV quality of the national seawater standard and could easily lead to phytoplankton blooms in nature if discarded with no treatment. The de-eutrophication abilities of U. pertusa varied greatly and depended mainly on the original eutrophic level the U. pertusa material was derived from. U. pertusa used to living in low DIN conditions had poor DIN removal abilities, while materials cultured in DIN-enriched seawater showed strong de-eutrophication abilities. In other words, the de-eutrophication ability of U. pertusa was evidently induced by high DIN levels. The de-eutrophication capacity of U. pertusa seemed to also be light dependent, because it was weaker in darkness than under illumination. However, no further improvement in the de-eutrophication capacity of U. pertusa was observed once the light intensity exceeded 300 μmol M2 S-1. Results of semi-continuous wastewater replacement experiments showed that U. pertusa permanently absorbed nutrients from eutrophicated wastewater at a mean rate of 299 mg/kg fresh weight per day (126 mg/kg DIN during the night, 173 mg/kg in daytime). Based on the above results, engineered de-eutrophication of wastewater by using a U. pertusa filter system seems feasible. The algal quantity required to purify all the eutrophicated outflow wastewater from the Qingdao Yihai Hatchery Center into oligotrophic level I clean seawater was also estimated using the daily discharged wastewater, the average DIN concentration released and the de-eutrophication capacity of U. pertusa.

基于碳氮稳定同位素组成分析的孔石莼对氨氮的吸收

氨氮(NH4-N)是水体中能被藻类直接吸收利用的无机氮。利用稳定同位素技术研究了不同浓度下孔石莼(Ulvapertusa)对NH4-N的吸收,藻类体内δ15N、δ13C的变化。结果显示:试验初始阶段,孔石莼大量吸收水体中的14NH4-N、12CO2用于自身组织的合成,导致水体中氨氮浓度、δ15N和δ13C急剧下降,约在5～25 h,这一阶段水体中氨氮浓度变化很小,藻体15N缓慢降低,达到平缓期;约在25 h后,氨氮浓度缓慢下降,海水中的底物浓度很低,水体中14NH4-N几乎被吸收殆尽,孔石莼开始大幅吸收15NH4-N,δ15N上升。δ13C在4 h后呈现无规律波动。

烟酰化孔石莼多糖的制备及抗氧化活性研究

目的探究烟酰化孔石莼多糖NU的最佳制备工艺,并测定其体外抗氧化活性。方法分别以甲酰胺(FA)、N,N-二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)为溶剂,烟酰氯盐酸盐为酰化剂,以氮元素含量为指标采用单因素法确定最佳溶剂,再采用正交设计法,考察孔石莼多糖U与酰化剂的质量比、U的质量浓度、反应时间、反应温度对反应的影响。经氮元素分析、红外光谱(IR)、核磁共振碳谱(13 C-NMR),推测烟酰化衍生物(NU)的化学结构。并研究NU对超氧阴离子自由基(O_2·^-)、羟自由基(·OH)的清除作用以及还原能力、金属螯合能力。结果烟酰化反应最佳条件:多糖与烟酰化试剂的质量比为1∶2,多糖的质量浓度15g·L-1,反应时间4h、反应温度为125℃。NU的结构已初步确定。对羟自由基(-OH)的清除作用及其还原能力、金属螯合能力,NU与U相比表现出更优的活性;但对超氧阴离子自由基(O_2^-)的清除作用二者无明显差异。结论通过确定的实验方案,烟酰化反应是成功的,烟酰化孔石莼多糖NU的抗氧化活性有显著增强。

绿藻孔石莼化学成分研究

目的研究绿藻孔石莼Ulva pertusa的化学成分。方法采用硅胶、ODS、Diaion HP-20、Sephadex LH-20等柱色谱和制备HPLC等技术进行分离纯化,根据理化性质和谱学数据鉴定化合物结构。结果从孔石莼乙醇提取物中分离得到18个化合物,分别鉴定为异植物醇(1)、3-吲哚甲酸(2)、1-O-十六碳酰基-3-O-(6′-硫代-α-D-脱氧吡喃葡萄糖基)甘油(3)、(2S)-1-O-十六碳酰基-3-O-[α-D-吡喃半乳糖基-(1→2)-β-D-吡喃半乳糖基]甘油(4)、3-甲基亚砜基丙酸(5)、3-氯丙酸(6)、酪醇(7)、对羟基苯甲酸(8)、对羟基苯乙酸(9)、6-乙烯基己内酯(10)、黑麦草内酯(11)、向日葵香波龙大柱酮D(12)、壬二酸(13)、琥珀酸(14)、8-羟基-(6E)-辛烯酸(15)、3-乙氧基丙酸(16)、正丁基-β-D-吡喃果糖苷(17)、焦谷氨酸正丁酯(18)。结论化合物1~16为首次从孔石莼中分离得到,化合物5、6、10、15和16为首次从天然产物中分离得到,化合物17和18为提取过程中产生的β-D-吡喃果糖苷和焦谷氨酸人工产物。