蔷薇藻藻蓝蛋白的稳定性研究

蔷薇藻Rhodella reticulata是属于红藻门的一种海洋单细胞微藻,其生长过程中产生藻胆蛋白、胞外多糖等生物活性物质。蔷薇藻经过破碎,通过硫酸铵沉淀和DEAE Sepharose FF柱层析后,可以分离出较纯的藻蓝蛋白。本文从pH、温度、光照、食品添加剂、金属离子等方面对蔷薇藻藻蓝蛋白稳定性作了较全面的研究：藻蓝蛋白在pH为7时最稳定;低温有利于保持藻蓝蛋白的活性;相对于光照,在避光条件下,藻蓝蛋白有较高的稳定性;适当浓度的蔗糖和葡萄糖都有利于藻蓝蛋白的保存;金属离子影响藻蓝蛋白的稳定性。     

伞藻

伞藻属(Acetabularia)是广泛分布于亚热带和热带海岸的单细胞绿藻,它生长在贝壳、珊瑚碎片或其他藻类之上,植物体钙化,成熟的植物体一般有几厘米高,某些大形种可达10厘米以上,较小的种有几毫米高。欧洲人称伞藻为“美人鱼的酒杯”或“美人鱼的阳伞”。在我国的广东和广西沿海、海南岛和西沙群岛等地有伞藻(A.caliculus)、棒形伞藻(A.clavata)等。     

层理鞭枝藻藻蓝蛋白和藻红蓝蛋白β亚基Cys-155的藻胆色素共价偶联

层理鞭枝藻(Mastigocladus laminosus PCC7603)藻蓝蛋白β-CPC和藻红蓝蛋白β-PEC中均存在2个藻胆色素结合位点(Cys-84和Cys-155),可与藻蓝胆素(简称PCB)发生共价偶联反应,已有研究证实编码基因为alr0617的裂合酶CpcS1是催化Cys-84与PCB共价偶联的裂合酶。在研究Cys-155与PCB共价偶联的过程中,通过BLAST软件同源性对比分析后,筛选出4个基因:cpcT1、cpcT2、cpcS1、cpcS2,其中基因cpcT1和cpcS2,利用分子克隆的技术,根据实验需要转到载体pCDFDuet上,通过DNA电泳和蛋白质电泳挑选出正确的克隆。此4个基因对应的质粒与在大肠杆菌内生成PCB必需的质粒pACYCDuet-ho1-pcyA,以及质粒pET-cpcB(C84S)或pET-pecB(C84A),共同转入大肠杆菌BL21(DE3)内,进行体内重组,得到各重组蛋白,经过亲和层析柱提纯并透析,过滤掉金属离子,纯化透析后的蛋白经过活性比较、蛋白质电泳以及锌染色、蛋白质变性等试验以及荧光和紫外吸收光谱等鉴定,通过与相应文献中PCB光谱的比对,确定编码基因为all5339的裂合酶CpcT1能高效地催化Cys-155与PCB共价偶联,而其余3个基因不能起到催化作用。由此,能催化脱辅基蛋白β-CPC和β-PEC的两个位点共价偶联PCB的裂合酶均被发现。实验对于研究藻胆蛋白的生物合成、光合作用捕光机理以及藻胆体的组装等有重要的意义。       

适合大量培养的红球藻藻种的筛选

研究了 4个雨生红球藻 (Haematococcuspluvialis)品系在 10℃、15℃、2 0℃、2 5℃和 2 8℃时的生长速率 (μ)、生物量、虾青素含量和产量 ,从中选出适合于大量培养的品系H .pluvialis2 6和H .pluvialisWZ。 2个品系的虾青素含量和产量分别达到 2 .4 1%— 3.16 % ,4 6 5 1— 5 4 35mg/L和 2 4 0 %— 2 5 9% ,39 84— 4 0 15mg/L。 2个品系的温度适应具有互补性 :H .pluvalisWZ适应于较低温度 (10℃— 2 0℃ ) ,H .pluvialis2 6适应于较高温度 (2 0℃— 2 8℃ ) ,在低温季节使用H .pluvialisWZ ,在高温季节使用H .pluvialis 2 6进行生产 ,可以延长生产期 ,提高产量     

菌-藻、藻-藻间化感作用初探

通过研究菌-藻、藻-藻间相互抑制作用,寻找抑制藻类水华的新途径。实验结果表明,选取的12种细菌均未见对藻有明显的抑制作用;在所试4种丝状真菌中,总状毛霉、黑曲霉对藻有不同程度的抑制;选取4种藻做单独培养与两两混合培养,观察生长情况以研究彼此间的关系,结果4种藻间,其生长优势由强到弱依次为栅藻>美丽颤藻>螺旋藻>念珠藻,前面的藻均对后面的藻有明显抑制作用。     

成油藻——布朗葡萄藻的研究

葡萄藻(Botryococcus braunii)是一种温带普生性种类。主要分布于淡水水体中。藻体是由几十到几百个细胞组成的,大小在30—500μm左右。含有较丰富的油类物质4,一般占藻体干重的25—40%,最高可达85%。葡萄藻可形成水华。       

鼠尾藻对赤潮异弯藻和中肋骨条藻的抑制作用

通过共培养的方法,研究了鼠尾藻（Surgassum thunbergii）培养水的过滤液、新鲜组织、干粉末、水溶性抽提液对赤潮异弯藻（Heterosigma akashiwo）和中肋骨条藻（Skeletonema costatum）生长的抑制效应,建立了分隔共培养系统并证明了抑制物质的存在,排除了细胞直接接触抑制的可能性.结果表明,在共培养实验中,鼠尾藻新鲜组织、干粉末及水溶性抽提液对赤潮异弯藻和中肋骨条藻的生长具有显著的抑制作用,且在较高浓度下对两种赤潮微藻的生长具有致死效应.在一次性及半连续培养方式下,鼠尾藻培养水过滤液对赤潮异弯藻的生长无抑制效应,而对中肋骨条藻的生长具有显著的抑制效应.     

有害赤潮藻种塔玛亚历山大藻的研究进展

塔玛亚历山大藻(Alexandrium tamarense)是一种全球分布的有毒涡鞭毛藻,在中国的渤海、东海和南海海域均有分布。塔玛亚历山大藻是一种主要的有毒赤潮原因种,而且它能产生可经食物链传递后在贝类、鱼类等生物体内大量蓄积的麻痹性贝毒素,对水域环境和人类健康都具有极大的危害。因此,针对塔玛亚历山大藻的产生、发展以及毒素的特征等开展了广泛而深入的研究。本文主要从塔玛亚历山大藻的生长环境、分子鉴定、藻际竞争关系以及治理等方面进行了综述,为研究塔玛亚历山大藻的利弊和监控提供参考。     

集胞藻6803藻胆体别藻蓝蛋白多克隆抗体的制备

藻胆体是蓝藻细胞主要的捕光天线色素超分子复合体,主要由核心体和外围的杆两部分组成,核心体主要由别藻蓝蛋白组装而成,参与光能向光合作用反应中心的传递.该研究通过PCR扩增出集胞藻6803别藻蓝蛋白α亚基(ApcA)编码基因apcA,构建表达质粒pET-32a(+)-apcA,并将其转入大肠杆菌BL21(DE3)pLysS菌株中;通过IPTG诱导表达重组蛋白,并利用组氨酸标签将可溶性目的蛋白进行亲和纯化后,免疫日本大耳白兔,从而获得多克隆抗体.间接ELISA法揭示ApcA抗体效价可高达1∶1 025 000;蛋白免疫印迹确定该抗体具有高度特异性.表明该研究成功制备了集胞藻6803藻胆体别藻蓝蛋白多克隆抗体,为进一步研究藻胆体的核心体在光能传递过程中所承担的重要生理角色奠定了生化基础.     

水母雪莲细胞生物反应器悬浮培养

Cell suspension culture of Saussurea medusa Maxim. was established in a 2 L stirred bioreactor for flavonoids production. After 12 days of culture, the biomass was 10.35 g DW·L-1, containing 428.6 mg/L flavonoids, which was 4.14% of the biomass (dry weight) under the condition of 25 ℃ and light intensity lower than 5 μmol·m-2·s-1. The utility pattern of sugar, change of dissolved oxygen and oxygen uptake rate were also studied.     

Soil Respiration under Three Land use Categories of Mountainous Region in Xishuangbanna,Yunnan

In order to study the difference of the soil respiration under different land uses in Xishuangbanna, field observations were conducted on the soil respiration rate from November 2010 to May 2011 under forest tea plantations, terrace tea plantations and secondary forests. Daily variations of soil respiration and its influence factors were analyzed. The results showed that there are different daily change patterns of soil respiration rate and soil moisture under different land uses, with statistically insignificance of soil respiration rate (P<0.05). The daily maximum soil respiration rate is almost at 14∶00-16∶00. The soil respiration rate and soil moisture vary most during the dry rainy transition season. The average soil respiration rate: forest tea plantations (2.62μmol·m-2s-1)相似文献   

Electron Transport Regulates Cellular Differentiation in the Filamentous Cyanobacterium Calothrix

Differentiation of the filamentous cyanobacteria Calothrix sp strains PCC 7601 and PCC 7504 is regulated by light spectral quality. Vegetative filaments differentiate motile, gas-vacuolated hormogonia after transfer to fresh medium and incubation under red light. Hormogonia are transient and give rise to vegetative filaments, or to heterocystous filaments if fixed nitrogen is lacking. If incubated under green light after transfer to fresh medium, vegetative filaments do not differentiate hormogonia but may produce heterocysts directly, even in the presence of combined nitrogen. We used inhibitors of thylakoid electron transport (3-[3,4-dichlorophenyl]-1,1-dimethylurea and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone) to show that the opposing effects of red and green light on cell differentiation arise through differential excitations of photosystems I and II. Red light excitation of photosystem I oxidizes the plastoquinone pool, stimulating differentiation of hormogonia and inhibiting heterocyst differentiation. Conversely, net reduction of plastoquinone by green light excitation of photosystem II inhibits differentiation of hormogonia and stimulates heterocyst differentiation. This photoperception mechanism is distinct from the light regulation of complementary chromatic adaptation of phycobilisome constituents. Although complementary chromatic adaptation operates independently of the photocontrol of cellular differentiation, these two regulatory processes are linked, because the general expression of phycobiliprotein genes is transiently repressed during hormogonium differentiation. In addition, absorbance by phycobilisomes largely determines the light wavelengths that excite photosystem II, and thus the wavelengths that can imbalance electron transport.     

转C4光合酶基因水稻的CO2交换和荧光特性

用转PEPC、PPDK、NADP-ME、PEPC+PPDK酶基因水稻(Oryza sativa L.)及原种为材料 ,研究了光合作用对光照、温度、CO2的响应和光抑制条件下的叶绿素荧光特性,结果如下: 1.转C4光合酶基因水稻的饱和光合速率比原种高,其中转PEPC、PEPC+PPDK双基因水稻的光饱和点比原种高200 μmol*m-2*s-1,饱和光合速率比原种分别高51.6%和 58.5%;转PEPC基因水稻的羧化效率比原种高49.3%,CO2补偿点降低26.2%;在高温(35 ℃)下,转PEPC基因水稻的光合速率比原种高17.5%.2.经光抑制处理8 d后,转PEPC、PEPC +PPDK酶基因水稻的PSⅡ光化学效率(Fv/Fm)和光化学猝灭(qP)下降20%- 30%,非光化学猝灭(qN)增加了约30%;但原种的Fv/Fm和qP下降了5 0%多,qN变化不明显,表明转C4光合基因水稻耐光抑制能力增强.这些结果为用生物技术提高水稻光合效率研究提供了新的依据和途径.     

低温弱光胁迫及恢复对切花菊光合作用和叶绿素荧光参数的影响

以切花菊品种‘神马’为试材,在偏低温弱光(16℃/12℃,PFD100μmol.m-2.s-1)和临界低温弱光(12℃/8℃,PFD60μmol.m-2.s-1)下分别胁迫11d,然后转入正常条件(22℃/18℃,PFD450μmol.m-2.s-1)恢复11d,研究不同低温弱光强度及恢复对菊花光合作用和叶绿素荧光参数的影响.结果表明:低温弱光导致菊花叶片的净光合速率(Pn)和气孔限制值(Ls)下降,而胞间CO2浓度(Ci)上升.偏低温弱光胁迫下菊花叶片暗适应下最大光化学效率(Fv/Fm)和初始荧光(Fo)无明显变化,但光适应下最大光化学效率(Fv′/Fm′)在处理前期略有下降,后期则有所回升;而临界低温弱光处理的Fo明显升高,Fv/Fm和Fv′/Fm′显著降低.PSⅡ光合电子传递量子效率(ΦPSⅡ)、光化学猝灭系数(qP)和表观光合电子传递速率(ETR)均随着低温弱光胁迫程度的增加和时间的延长而降低;偏低温弱光处理植株在解除胁迫后能迅速恢复到对照水平,而临界低温弱光处理植株回升速度较慢;同时,低温弱光胁迫下吸收光强用于分配光化学反应部分(Prate)的比例减少,而天线热耗散(Drate)和反应中心的能量耗散(Ex)比例上升,但天线热耗散为过剩光能的主要分配途径.     

The Possible Mechanism of Photoinhibition of Purified PSI Complexes

The protecting effect of histidine on the photodamage of pigments and proteins of the isolated PSⅠ particles from the chloroplast of Spinacia oleracea L. during the strong illumination (2 300 μmol·m-2·s-1) was studied by spectroscopy and SDS-PAGE. The absorbance of PSⅠ particles decreased during the strong illumination treatment, but the decrease would be slowed down in the presence of externally added histidine after 30 min illumination. The decrease of CD （circular dichroism）signal intensities of PSⅠ particles also was slowed down by the added histidine after about 10 min illumination. The retarded protecting effect of the added histidine on the photobleaching of pigments of PSⅠ complexes implied that the mechanisms of photoinhibition of isolated PSⅠ complexes are different from early stage to later stage during the strong illumination treatment. In addition, the added histidine suppressed the decrease of 77 K fluorescence yield of PSⅠ particles during the illumination. SDS-PAGE showed that the added histidine not only protected the reaction center proteins of PSⅠ particles, but also protected other subunits of PSⅠ particles from degradation.     

Excitation energy transfer to Photosystem I in filaments and heterocysts of Nostoc punctiforme

Cyanobacteria adapt to varying light conditions by controlling the amount of excitation energy to the photosystems. On the minute time scale this leads to redirection of the excitation energy, usually referred to as state transitions, which involves movement of the phycobilisomes. We have studied short-term light adaptation in isolated heterocysts and intact filaments from the cyanobacterium Nostoc punctiforme ATCC 29133. In N.punctiforme vegetative cells differentiate into heterocysts where nitrogen fixation takes place. Photosystem II is inactivated in the heterocysts, and the abundancy of Photosystem I is increased relative to the vegetative cells. To study light-induced changes in energy transfer to Photosystem I, pre-illumination was made to dark adapted isolated heterocysts. Illumination wavelengths were chosen to excite Photosystem I (708 nm) or phycobilisomes (560 nm) specifically. In heterocysts that were pre-illuminated at 708 nm, fluorescence from the phycobilisome terminal emitter was observed in the 77 K emission spectrum. However, illumination with 560 nm light caused quenching of the emission from the terminal emitter, with a simultaneous increase in the emission at 750 nm, indicating that the 560 nm pre-illumination caused trimerization of Photosystem I. Excitation spectra showed that 560 nm pre-illumination led to an increase in excitation transfer from the phycobilisomes to trimeric Photosystem I. Illumination at 708 nm did not lead to increased energy transfer from the phycobilisome to Photosystem I compared to dark adapted samples. The measurements were repeated using intact filaments containing vegetative cells, and found to give very similar results as the heterocysts. This demonstrates that molecular events leading to increased excitation energy transfer to Photosystem I, including trimerization, are independent of Photosystem II activity.     

光照条件对‘寒富’苹果叶片结构和光合特性的影响

以‘寒富’苹果为试材,利用光学显微镜技术和气体交换等方法,研究了光照条件对盆栽和田间条件下‘寒富’苹果叶片结构和光合特性的影响.结果表明： 同种栽培方式下,与全光照条件相比,遮阴环境下‘寒富’苹果叶片的栅栏组织、海绵组织以及叶片总厚度均降低,其中,栅栏组织分别降低34.5%(盆栽)和25.0%(大田),叶片总厚度分别降低27.1%(盆栽)和18.3%(大田);遮阴环境下大田‘寒富’苹果叶片的光补偿点(LCP)最低,为(30.8±1.3） μmol·m^-2·s^-1,全光照比遮阴环境下叶片饱和光强分别高22.7%(盆栽)和48.2%(大田);盆栽不同光照环境下叶片对强光的适应能力不同,突然转入强光下,达到最大光合速率15.4 μmol·m^-2·s^-1(盆栽全光照)和12.7 μmol·m^-2·s^-1(盆栽遮阴)的光合启动时间不同,分别为23和33 min.表明长期遮阴影响‘寒富’苹果叶片质量及光合能力.     

Hormogonia in two nostocalean cyanophytes (cyanobacteria) from the genera Hapalosiphon and Fischerella

The formation of hormogonia in the nostocalean cyanophytes/cyanobacteria Hapalosiphon fontinalis (C. Agardh) Bornet and Fischerella sp. was studied in natural populations collected from the Klin peatbog, northern Slovakia. Hormogonia were produced terminally in lateral branches of filaments (both species), or also directly on the main branches (Fischerella sp.). In contrast to vegetative filaments, hormogonia were not ramified, lacked heterocytes, were embedded in mucilaginous envelopes, were able to move, and their cells contained aerotopes. They were released by gliding through an opening in the sheath at the end of lateral branches of filaments. Released hormogonia of H. fontinalis were solitary or agglomerated into common fascicles morphologically resembling planktic colonies of Aphanizomenon flos-aquae (L.) Ralfs ex Bornet et Flahault or Dolichospermum affine (Lemmermann) Wacklin, Hoffmann et Komárek (syn. Anabaena affinis Lemmermann). Occasionally, lateral or sessile Nostochopsis-like heterocytes and apical spherical monocytes were formed on the main filaments. Hormogonia of Fischerella sp. were formed not only in apical part of lateral trichomes, but also directly on the main trichomes. Their cells were markedly larger than the vegetative cells and possessed well-developed aerotopes. Released hormogonia remained solitary, and were not agglomerated into fascicles. Apical hormogonia were released by gliding through an opening in the sheath at the end of lateral branches of filaments, and basal hormogonia were released by breaking off the main axis. In contrast to filaments of H. fontinalis which were very common and represented the dominant species of the cyanophyte communities in the locality, filaments of Fischerella sp. were observed only in one sample and for a limited period. This is the first record of a representative of the genus Fischerella in Slovakia.     

农杆菌介导的单子叶植物早熟禾的转化

利用种子和胚分别在两种培养基K3和K5诱导产生了早熟禾(Poa pratensis L.)一个品种Mado的胚性愈伤组织.K3培养基含有10.0μmol/L的二氯苯氧乙酸(2,4-D)、0.5μmol/L的苄氨基嘌呤(BAP).K5培养基是K3另加0.5μmol/L的硫酸铜.光照条件为20～30 μmol.m-2.s、16 h光照、8 h黑暗.温度保持在24℃.用携有bar基因和gus基因的pDM805质粒转化的农杆菌AGL1对胚性愈伤组织进行转化.共得到4个转基因株系.影响转基因效率的主要因素有愈伤组织的胚性、光照条件、共转化时间、抗生素浓度、选择压力.本研究建立了单子叶早熟禾农杆菌介导的转基因方案.