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1.
Temperature dependence of filament length ofAnabaena spiroides Klebahn var.crassa Lemm. was examined for a strain isolated from Lake Kasumigaura, Japan. The length of the algal filaments is shown to have good correspondence with the thermal master reaction of cell multiplication.  相似文献   

2.
Thirty characteristics of 14 Nostoc and 10 Anabaena species were analyzed from previously published data. Using standard numerical taxonomic methods, simple matching coefficients were calculated and a phenogram drawn. The analysis revealed that some of the central characteristics of Nostoc are: a punctiforme stage; motile reproductive stage; plant mass with a dull to shiny luster, non-veined surface, and nonfimbriate margin; some spherical vegetative cells; no cylindrical heterocysts; and some spherical, but no cylindrical akinetes. Some of the central characteristics of Anabaena that were revealed are: no punctiforme stage; a motile vegetative stage; plant mass with a shiny luster, veined surface, and fimbriate margin; no spherical vegetative cells; some cylindrical heterocysts; and some cylindrical, but no spherical, akinetes. In general, Anabaena has larger akinetes and vegetative cells than Nostoc. Based on 30 morphological characteristics and the clustering data of the phenogram, keys were constructed for the Nostoc and Anabaena species studied. The data clearly support two separate and distinct, though similar genera and, less sharply, the separation of the 24 species. The more useful characteristics for separation of the species are size and shape of akinetes, vegetative cells, and heterocysts; color and luster of plant mass; veined plant mass surface; margin fimbriate; and shape of plant mass in nature.  相似文献   

3.
Biological factors have been found which can cause variable toxicity of colony and clonal isolates of Anabaena flos-aquae (Lyngb.) de Bréb. when cultured in the laboratory. These factors help to explain some of the variable toxicity of and animal susceptibility to A. flos-aquae blooms in nature. Two bacteria in the Enterobacteriaceae isolated from a toxic waterbloom, depressed toxin production in selected bacteria-free toxic clones of A. flos-aquae. These toxin-depressing bacteria decreased culture toxicity 3-fold from 80 to 240 mg/kg (intra-peritoneal in male mice). Many colony isolates from a toxic bloom had minimum lethal dosages (LDmin) greater than 240 mg/kg. This was because they were composed of mixtures of toxic and nontoxic filaments. The oral LDmin of the toxin from A. flos-aquae clonal isolate NRC-44-1 varied significantly for 6 different animal species. Using these oral LDmin it is estimated that a surface-concentrated bloom of toxic A. flos-aquae, having a biomass density of 20 mg/ml dry weight, would cause death of ducks or calves when 20 ml/kg was consumed whereas a monogastric animal such as a rat would require 80 ml/kg.  相似文献   

4.
Mono-glucoside and -galactoside derivatives of long-chain polyhydroxy alcohols were identified in an unsaponifiable fraction from Anabaena cylindrica. The major alcohol moiety in these lipids was 1,3,25-trihydroxyhexacosane (I), which was accompanied by much smaller quantities of a tetrahydroxyalcohol, probably 1,3,25,27-tetrahydroxyoctacosane (III).  相似文献   

5.
以Tn5 10 87b诱变鱼腥藻PCC712 0 ,筛选不能利用氮气生长、异形胞图式发生变化的突变株。突变株 # 180 1经缺氮诱导 2 4h后无异形胞形成 ,48h后沿藻丝形成少量成熟异形胞 ,占藻细胞总数比例为 2 .8% ,其异形胞发育速度和形成频率均与野生型有显著区别。以ClaⅠ酶切该突变株总DNA、自环化后以电泳冲法转化大肠杆菌 ,回收带有插入位点两侧DNA片段的转座子Tn5 10 87b。经测序确定转座子位于未知功能基因alr0 0 99第 14 8和 14 9碱基之间。为证明突变性状确由alr0 0 99内的插入突变引起而不是由于其他二次突变 ,通过同源双交换将含新霉素抗性基因的C .K2片段定向插入基因组中alr0 0 99的EcoRV位点 ,获得重构的鱼腥藻突变株DR2 14 ,其表型与原突变株 # 180 1相同。以上结果表明alr0 0 99或其下游基因是鱼腥藻PCC712 0基因组中与异形胞发育和图式形成相关的一个新区域。  相似文献   

6.
张晨  刘志伟  郭勇 《生物技术》2003,13(4):27-29
为了进一步探索转基因鱼腥藻高密度培养的方法,在小型气升式反应器中研究了CO2对转基因鱼腥藻7120培养的影响。结果发现转基因鱼腥藻培养过程中通入5% CO2能促进藻细胞生长,12d生物量提高7.44%,由于光照限制,不能大幅提高15d收获生物量,但生长周期能缩短近20%;而高浓度(10%)的CO2抑制转基因鱼腥藻的生长。CO2是通过调节pH值和影响碳源利用来影响藻细胞生长的,合适浓度的CO2有利于转基因鱼腥藻的培养。  相似文献   

7.
广东省水库的蓝藻污染状况与水质评价   总被引:19,自引:1,他引:19       下载免费PDF全文
于2000年的丰水期和枯水期对广东省19个大中型水库的浮游植物状况进行了调查,并根据浮游植物群落结构、多样性指数、蓝藻污染状况和营养状态指数对水库的水质进行了分析。结果表明,大部分水库为蓝藻型水体,优势种类主要是能产生毒素的微囊藻类,而且蓝藻种类数和细胞密度与水库水质密切相关。蓝藻细胞密度和百分比分别为0.1×104-6728.4×104 cellsL-1和0.53%-99.2%。大部分水库受到了一定程度的污染,属于中营养型;东江流域的新丰江水库和白盘珠水库水质优良,为贫营养型;而位于经济较发达的沿海地区的鹤地水库、石岩水库和契爷石水库已受到严重污染。东江流域和北江流域水库水质普遍较好,而粤西沿海地区和珠江三角洲地区水库则污染较为严重。  相似文献   

8.
蓝藻毒素的研究概况   总被引:5,自引:0,他引:5  
综述了近20年来有关藻毒素检测技术、脱毒降毒方法、微囊藻毒素(MC)与环境因子关系、MC对水生生物的影响、合成机理、Microcystis aeruginosa PCC7806专题及其他相关研究的进展。国内在此领域上的研究还比较薄弱,且更多集中在宏观层面上。  相似文献   

9.
One new species of Sphaeroplea (S. bourrellyii Islam), and six taxa, hitherto unrecorded from Iraq, namely, Dichotomosiphon tuberosus (A. Br.) Ernst, Johannesbaptistia pellucida (Dickie) Taylor & Drouet, Microcoleus chthonoplastes Thuret ex Gomont, M. lacustris (Rab.) Farlow, Gloeotrichia longiarticulata G. S. West, and Ammatoidea (?) normanni W. & G. S. West are described and illustrated.  相似文献   

10.
南亚热带不同营养水平水库的蓝藻组成与动态   总被引:3,自引:0,他引:3  
2004年调查了广东省境内的新丰江水库和契爷石水库的蓝藻分布特征.结果表明:共检测到蓝藻18属,绝大多数为丝状体和群体种类.常见属有假鱼腥藻(Pseudanabaena)、湖生蓝丝藻(Limnothrix)、微囊藻(Microcystis)和蓝纤维藻(Dactylococcopsis).新丰江水库和契爷石水库蓝藻细胞密度分别为4~249和1 911~114 228 cells·ml-1,富营养化的契爷石水库蓝藻细胞密度比贫营养型的新丰江水库高出3个数量级;2座水库最高蓝藻细胞密度均出现在夏季,温度是引起2座水库蓝藻细胞密度的季节性变化的主要因素;在新丰江水库,微囊藻是优势蓝藻种类之一,相对丰度35%~97%,夏季细胞密度高于其它季节;在契爷石水库,虽然微囊藻细胞密度比新丰江水库高出1个数量级,但其相对丰度不超过3%;假鱼腥藻和湖生蓝丝藻是契爷石水库的优势蓝藻种类,多数情况下相对丰度超过50%;水体稳定性和由透明度主导的水体光照条件的差别可能是导致两座水库蓝藻由不同生活类型的种类占优势的主要原因.  相似文献   

11.
Clonal isolates of Peridinium volzii Lemmerman were analyzed morphologically and biochemically. Morphological observations at the light microscope level show the clones to be different varieties and forms of the same species. Biochemical analysis by enzyme electrophoresis and flow cytometric determination of nuclear DNA quantities indicates that these isolates are genetically heterogeneous without any clear correlation existing between morphological variation and biochemical variation. Isozyme analysis, however, indicates that strains from the same location are generally more related to each other than they are to isolates with other geographical origins. In general, our results suggest the presence of genetic redundancy and a multiclonal origin for individuals of the same species present in the same locale.  相似文献   

12.
A new species of endolithic cyanophyte, Hyella gigas Lukas and Golubic (Order: Pleurocapsales), differs from other species of Hyella by its larger cell and filament dimensions and its laminated, often pigmented sheath. It bores into mollusk shells and other marine carbonate substrates on the east coast of North America, the Bahama Islands and the Northern Mediterranean Sea, where it is found from near mean low water down to 25 m depth. This comparatively shallow maximum depth is probably due to the limited capacity of Hyella gigas to adapt to changing light quality and intensity. We reject the suppression of the genus Hyella as proposed by Drouet and Daily.  相似文献   

13.
目的:通过在培养基中添加葡萄糖的方法,提高转基因鱼腥藻的产量和人肿瘤坏死因子(hTNF)-α的表达率。方法:在葡萄糖浓度为0~300mmol/L的范围内,进行了转hTNF-α鱼腥藻IB02的摇瓶混合营养培养,用比浊法和酶联免疫法测定转基因鱼腥藻的生长和hTNF-α的表达。结果:添加葡萄糖的藻液最高生长密度是未添加葡萄糖的3.5倍,且hTNFa的表达率也提高至4倍。结论:在各种葡萄糖浓度下,葡萄糖的利用都不明显。  相似文献   

14.
The paper describes the morphology and reproduction of a new species of Symphyonemopsis viz. S. pantii n. sp. isolated from enrichment cultures of a soil sample collected from the campus of Sangeet Samiti, Allahabad (India). Thalli grow as dark blue-green, small, wooly patches on soil surface but as cushion-like growths on agar plates. It has a prostrate and erect system. The latter bears secondary branches of almost equal breadth. It possesses both false and true branches. Usually true branches are reverse V-shaped. The alga shows formation of hormocysts and akinetes. In old cultures usually the main filament becomes multiseriate. The crescent-shaped stages of hormocysts are also present here. Cells of the present alga are constricted at the cross-walls On comparison it was found to come close to Symphyonemopsis katniensis Tiwari et Mitra but differs in certain fundamental characters. It is, therefore, described as a new species viz. S. pantii n. sp. (Cyanophyta, Stigonematales, Mastigocladaceae).  相似文献   

15.
16.
鱼腥藻提取液对水稻生长发育和产量的促进作用   总被引:1,自引:1,他引:1  
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  相似文献   

17.
砷对蓝藻光合作用和细胞生长的影响   总被引:9,自引:0,他引:9       下载免费PDF全文
在世界的许多地方, 砷污染是一个严重的问题, 尤其是水体中的污染程度更加严重。砷主要以As( V) 和As( ó ) 形式存在。由于AsO43- 在结构上与PO43-很相似, 它通过磷转运途径进入细胞, 因此砷的毒性主要是源于对磷代谢的干扰[1] 。砷对于人和动物的危害性是人所共知的, 它会引发细胞凋亡, 导致多种组织和器官发生癌变, 从而引起死亡。但是砷对于水体生态系统中的重要类群) 藻类的生理和生长的影响报道较少。  相似文献   

18.
利用鱼腥藻作为饲料的研究   总被引:2,自引:0,他引:2  
鱼腥藻粉作为肉鸡、全雌鲤、青虾和对虾的饲料研究结果表明:2%的鱼腥藻粉替代鱼粉作为肉鸡饲料试验,肉鸡的个体平均增重效果与对照相当,屠宰率、半净膛率和全净膛率都有所提高;同时还具有改善肉质色泽的效果。对重金属的含量分析发现,食鱼腥藻的鸡除锌的含量略高外,铜、铁、锰、镉及铝的含量都低于对照组。添加2%的鱼腥藻粉在网箱中进行小试和大面积试验,结果都表明鱼腥藻粉对全雌鲤的生长有明显的效果,并能提高全雌鲤鱼种的成活率和降低饵料系数,利用鱼腥藻粉配合饲料在网箱和大面积养殖青虾试验表明,具有促进生长,提高产量的作用.对虾试验结果表明,在饵料中添加2%的鱼腥藻粉,饲喂45d后,对虾的体长增加了14.49%;体重增加了10.43%。这些研究结果表明利用鱼腥藻作为家禽及水产养殖动物的饲料具有相当大的应用前景。  相似文献   

19.
    
The effect of temperature and oxygen on nitrogenase activity in two heterocystous cyanobacteria, Anabaena variabilis Kütz. ATCC29413 and Nostoc sp. PCC7120, was investigated. The cyanobacteria were grown under a 12:12 light:dark (L:D) cycle at 27°C and were subsequently exposed to different temperatures (27, 36, 39, and 42°C) at different steady‐state O2 concentrations (20, 10, 5, 0%). Light response curves of nitrogenase activity were recorded under each of these conditions using an online acetylene reduction assay combined with a sensitive laser photoacoustic ethylene detection method. The light response curves were fitted with the rectangular hyperbola model from which the model parameters Nm, Nd, and α were derived. In both strains, nitrogenase activity (Ntot = Nm + Nd) was the highest at 39°C–42°C and at 0% O2. The ratio Ntot/Nd was 4.1 and 3.1 for Anabaena and Nostoc, respectively, indicating that respectively 25% and 33% of nitrogenase activity was supported by respiration (Nd). Ntot/Nd increased with decreasing O2 concentration and with increasing temperature. Hence, each of these factors caused a relative increase in the light‐driven nitrogenase activity (Nm). These results demonstrate that photosynthesis and respiration both contribute to nitrogenase activity in Anabaena and Nostoc and that their individual contributions depend on both O2 concentration and temperature as the latter may dynamically alter the flux of O2 into the heterocyst.  相似文献   

20.
    
Iron availability may limit carbon and nitrogen fixation in the oceans. The freshwater cyanobacterium, Anabaena, was used as a laboratory model for the biochemical and physiological effects of iron. Increased iron nutrition, in the range of 10?8 M to 10?6 M resulted in increases of approximately four fold in carbon and nitrogen fixation rates. Chlorophyll concentration increased, and the relative amount of in vivo fluorescence was reduced with more iron. Natural samples of Trichodesmium, collected off Barbados and incubated with increased iron for two days, showed similar effects. Trichodesmium responded to iron additions indicating that it may be Fe limited in its natural environment. These responses to iron are consistent with the biochemical roles of iron in photosynthesis and nitrogen fixation. The results are discussed in the geochemical context of the sporadic total iron input to tropical oceans and possible implications to spatial and temporal patterns of productivity.  相似文献   

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