十四属蓝藻液泡的检查和分离

采用压片法,渗透冲击法和原生质球法,对14个属的不同蓝藻进行了液泡存在的检查和分离试验,每种蓝藻都检查到液泡,无一例外。其中鱼腥藻、念珠藻、项圈藻、席藻、简孢藻等都能形成液泡化原生质球,原生质球低渗破裂释放液泡,液泡得率极高,不同种的液泡都耐低渗。因此,本研究证明液泡在蓝藻中的存在是普遍的。     

Anatoxin-a synthetase gene cluster of the cyanobacterium Anabaena sp. strain 37 and molecular methods to detect potential producers

Cyanobacterial mass occurrences are common in fresh and brackish waters. They pose a threat to water users due to toxins frequently produced by the cyanobacterial species present. Anatoxin-a and homoanatoxin-a are neurotoxins synthesized by various cyanobacteria, e.g., Anabaena, Oscillatoria, and Aphanizomenon. The biosynthesis of these toxins and the genes involved in anatoxin production were recently described for Oscillatoria sp. strain PCC 6506 (A. Méjean et al., J. Am. Chem. Soc. 131:7512-7513, 2009). In this study, we identified the anatoxin synthetase gene cluster (anaA to anaG and orf1; 29 kb) in Anabaena sp. strain 37. The gene (81.6% to 89.2%) and amino acid (78.8% to 86.9%) sequences were highly similar to those of Oscillatoria sp. PCC 6506, while the organization of the genes differed. Molecular detection methods for potential anatoxin-a and homoanatoxin-a producers of the genera Anabaena, Aphanizomenon, and Oscillatoria were developed by designing primers to recognize the anaC gene. Anabaena and Oscillatoria anaC genes were specifically identified in several cyanobacterial strains by PCR. Restriction fragment length polymorphism (RFLP) analysis of the anaC amplicons enabled simultaneous identification of three producer genera: Anabaena, Oscillatoria, and Aphanizomenon. The molecular methods developed in this study revealed the presence of both Anabaena and Oscillatoria as potential anatoxin producers in Finnish fresh waters and the Baltic Sea; they could be applied for surveys of these neurotoxin producers in other aquatic environments.     

A comparison of the carotenoids of strains of Oscillatoria and Spirulina (Cyanobacteria)

The qualitative and quantitative carotenoid composition is reported for (i) a red and a green strain of Oscillatoria limnetica and a green strain of Spirulina platensis cultivated under identical conditions and (ii) a red and a green strain of Spirulina subsalsa grown under identical conditions. No correlation between colour and carotenoid content was obtained. However, differences in carotenoid composition within the Oscillatoria and Spirulina strains were observed. Both oscillol diglycoside ex Oscillatoria limnetica and myxol glycoside ex Spirulina platensis were mixed α-glycosides with chinovose-fucose present in ca 7:2 ratio. Analytical procedures are given. The chemosystematic implications for the current taxonomy of the genera Oscillatoria and Spirulina are discussed.     

Pigment analysis and ammonia excretion in herbicide tolerant cyanobacteria

Isolation of cyanobacteria was attempted from herbicide applied rice soils. The predominant genera were Westiellopsis followed by Anabaena, Nostoc and Oscillatoria. The herbicide tolerance was further tested by growing the cyanobacterial cultures in BG-11 medium supplemented with varying concentrations of the commonly used rice herbicide, viz butachlor under in vitro condition. The chlorophyll-a, phycobiliproteins and ammonia excretion were assessed at periodic intervals. Westiellopsis showed the maximum tolerance followed by Anabaena, Nostoc and Oscillatoria.     

A COMPOSITE RATING OF ALGAE TOLERATING ORGANIC POLLUTION2

From information on pollution-tolerant algae compiled from reports from 165 authors, the genera and species most often referred to as significant fall into a relatively stable series. Diatoms, pigmented flagellates, green, and blue-green algae are all well represented among the pollution-tolerant genera and species. The top 8 genera are Euglena, Oscillatoria, Chlamydomonas, Scenedesmus, Chlorella, Nitzschia, Navicula, and Stigeoclonium, and the top 5 species, Euglena viridis, Nitzschia palea, Oscillatoria limosa, Scenedesmus quadricauda, and Oscillatoria tennis. In some genera, e.g., Euglena, a single species is far more significant than all others as a pollution-tolerant form. In other genera, e.g., Oscillatoria, only a slight difference distinguishes the pollution tolerance of 2 or more species. Algal genus and species pollution indices arc presented for use in rating water samples with high organic pollution.     

An investigation into the possible light-shielding role of gas vacuoles in a planktonic blue-green alga

When the gas vacuoles of Anabaena flos-aquae Bréb. ex Born. et Flah. are collapsed, the optical properties of the alga change. While this may suggest a light-shielding role, photosynthetic measurements indicate that intact gas vacuoles reduce the light falling on the thylakoids by only 4%, or less. Intact gas vacuoles offer no protection against the lethal effects of ultraviolet light. When the alga is grown at high light intensity the gas vacuoles are fewer in number but are oriented peripherally in the cells. However, this does not markedly affect their light shielding efficiency. Spectrophotometric measurements carried out by others indicate a light shielding role by gas vacuoles in a non-planktonic blue-green alga, Nostoc muscorum Kütz., but do not give a quantitative estimate of this effect. In Anabaena no definite evidence of light-shielding is obtained by such a method. All of the experiments described were conducted with dilute algal suspensions to investigate shielding effects in individual cells. Possible self-shading effects in dense suspensions and surface water blooms require further investigation.     

97 Sensitivity of cyanobacteria to a potential biological control agent, bacterium SG-3

Cyanobacteria cause many problems in freshwater ecosystems. For example, the production of off-flavor compounds by cyanobacteria causes serious problems in catfish aquaculture. Control of cyanobacteria is generally limited to treatment with copper compounds, which are non-selective and sometimes ineffective at controlling certain species of cyanobacteria. Biological control could provide selective management by removing unwanted species while leaving desirable algae species. A bacterium (SG-3) (NRRL B-30043) lyses a number of planktonic species of cyanobacteria including bloom-forming species of Anabaena and Oscillatoria . We tested SG-3 for activity against 10 isolates, representing seven species, of mat-forming cyanobacteria within the genera Oscillatoria, Lyngbya , and Phormidium . Plugs (0.5 cm diameter) were cut from mats of the cyanobacterium, inoculated with liquid cultures of SG-3, and incubated as static cultures. The reduction in dry weights ranged from –0.5% to 90% compared to the untreated controls and appeared to be species specific. For example, dry weight reductions of Oscillatoria deflexoides and O. amoena ranged from 80 to 90% whereas the reduction of O. limosa tended to be lower at 36 to 72%. Although results varied among and within species, they indicate that this bacterium could have potential for use as a biological control for mat-forming cyanobacteria. Light microscopic observations indicate the bacteria do not penetrate the cyanobacteria cells. Currently, we are studying the possible causes of the observed cell lysis.     

环境因子与螺旋藻(节旋藻)分布及丰度的相关性分析

【目的】2015年7月至2015年9月,对海岸线较长、湿地类型比较多样化的渤海湿地及周边水域中螺旋藻(节旋藻)的分布进行研究,并对其与环境因子的相互关系进行分析。【方法】采用相关分析和灰关联分析对螺旋藻(节旋藻)数量与环境因子关系进行分析。【结果】螺旋藻(节旋藻)数量与pH、盐度、总氮(TN)、总磷(TP)、化学需氧量(COD)、氨氮(NH_3-N)呈显著正相关(P0.05,P0.01),与溶解氧(DO)呈显著负相关(P0.05,P0.01),与温度呈负相关,但相关不显著(P0.05);灰关联分析结果表明:各环境因素对螺旋藻数量的关联程度依次为:CODpHTN温度TPDO盐度NH_3-N。【结论】渤海海滨湿地及周边水域中螺旋藻(节旋藻)资源丰富,对螺旋藻(节旋藻)分布影响最大的环境因子是COD,最小是NH_3-N。     

The effect of dehydration and ion stress on carbon dioxide fixation in drought-tolerant phototrophic micro-organisms

Abstract Two cyanobacterial strains, Crinalium epipsammum SAB 22.89 and Tychonema sp. SAB 23.89 and the green alga Klebsormidium flaccidum were examined for their ability to fix carbon during controlled dehydration. Additionally the cyano-bacterium C. epipsammum was subjected to dehydration in the presence of a range of NaCl concentrations in order to discriminate between the effects caused by either matrix or ionic forces. K. flaccidum and C. epipsammun were proved to be able to maintain full carbon-fixing activity until the water content approached zero. Tychonema sp. appeared to reduce its activity in an immediate response to becoming dehydrated. The experiments have further substantiated the view on the strategy of these three drought-tolerant organisms to oscillating water availability. The cyano-bacteria, as the initial colonizers inhabiting the barren sand, are able to react quickly to changing water availability, thereby improving the water retention quality for the green alga. The latter organism will function well in an environment with improved water retention characteristics. C. epipsammum demonstrated extensive differences in carbon-fixing activities during dehydration in the presence of various concentrations of NaCl. This implies that when C. epipsammum is dehydrated in soils low in salt, the water availability, which is given by the matrix water potential, is determining the photosynthetic activity, whereas in more saline soils (equivalent to 50 mM NaCl and higher) the versatility towards osmotic adjustment plays an important role.     

Algicidal properties of Acacia nilotica

The algicidal activity of aqeuous extracts of the pods of Acacia nilotica (L.) Willd. ex Del. was tested in artificial ponds. Algae belonging to the genera Rivularia, Oscillatoria, Spirulina, Chroococcus, Microcystis (Cyanophyceae), Pediastrum, Coelastrum (Chlorophyceae), Spirogyra, Cosmarium, Closterium (Conjugophyceae), Euglena (Euglenophyceae) and Cyclotella (Bacillariophyceae) were successfully controlled with this extract.     

不同生境下的钝顶螺旋藻RAPD分析

本文对不同生境下的钝顶螺旋藻Spirulina (Arthrospira) platensis进行了RAPD分析。结果表明, 鄂尔多斯高原碱湖和Chad湖的钝顶螺旋藻基因组DNA扩增多态性片段同源性为 48.23%。2 个样品在分子遗传水平上存在着较大的差异, 这是由于各自生态环境明显不同和长期地理隔离造成的。     

Molecular classification of commercial Spirulina strains and identification of their sulfolipid biosynthesis genes

Cyanobacterial strains of the genus Spirulina have recently been identified as an excellent source of sulfolipids, some of which possess anti-HIV properties. Thus, to investigate the distribution of sufolipid biosynthesis pathways in Spirulina, a genetic screening/phylogentic study was performed. Five different strains of Spirulina [Spirulina (Jiangmen), Spirulina sp., S. platensis, S. maxima, and Spirulina seawater] sourced from different locations were initially classified via 16S rDNA sequencing, and then screened for the presence of the sulfolipid biosynthesis genes sqdB and sqdX via a PCR. To assess the suitability of these strains for human consumption and safe therapeutic use, the strains were also screened for the presence of genes encoding nonribosomal peptide synthases (NRPSs) and polyketide synthases (PKSs), which are often associated with toxin pathways in cyanobacteria. The results of the 16S rDNA analysis and phylogenetic study indicated that Spirulina sp. is closely related to Halospirulina, whereas the other four Spirulina strains are closely related to Arthrospira. Homologs of sqdB and sqdX were identified in Spirulina (Jiangmen), Spirulina sp., S. platensis, and the Spirulina seawater. None of the Spirulina strains screened in this study tested positive for NRPS or PKS genes, suggesting that these strains do not produce NRP or PK toxins.     

PHYLOGENY AND GENETIC VARIANCE IN TERRESTRIAL MICROCOLEUS (CYANOPHYCEAE) SPECIES BASED ON SEQUENCE ANALYSIS OF THE 16S rRNA GENE AND ASSOCIATED 16S–23S ITS REGION1

Thirty‐one strains of Microcoleus were isolated from desert soils in the United States. Although all these taxa fit the broad definition of Microcoleus vaginatus (Vaucher) Gomont in common usage by soil algal researchers, sequence data for the 16S rRNA gene and 16S–23S internal transcribed spacer (ITS) region indicated that more than one species was represented. Combined sequence and morphological data revealed the presence of two morphologically similar taxa, M. vaginatus and Microcoleus steenstrupii Boye‐Petersen. The rRNA operons of these taxa were sufficiently dissimilar that we suspect the two taxa belong in separate genera. The M. vaginatus clade was most similar to published sequences from Trichodesmium and Arthrospira. When 16S sequences from the isolates we identified as M. steenstrupii were compared with published sequences, our strains grouped with M. chthonoplastes (Mertens) Zanardini ex Gomont and may have closest relatives among several genera in the Phormidiaceae. Organization within the 16S–23S ITS regions was variable between the two taxa. Microcoleus vaginatus had either two tRNA genes (tRNA^Ile and tRNA^Ala) or a fragment of the tRNA^Ile gene in its ITS regions, whereas M. steenstrupii had rRNA operons with either the tRNA^Ile gene or no tRNA genes in its ITS regions. Microcoleus vaginatus showed no subspecific variation within the combined morphological and molecular characterizations, with 16S similarities ranging from 97.1% to 99.9%. Microcoleus steenstrupii showed considerable genetic variability, with 16S similarities ranging from 91.5% to 99.4%. In phylogenetic analyses, we found that this variability was not congruent with geography, and we suspect that our M. steenstrupii strains represent several cryptic species.     

不同生境下的钝顶螺旋藻RAPD分析

本文对不同生境下的钝顶螺旋藻Spirulina(Arthrospira)platensis进行了RAPD分析.结果表明,鄂尔多斯高原碱湖和Chad湖的钝顶螺旋藻基因组DNA扩增多态性片段同源性为48.23%.2个样品在分子遗传水平上存在着较大的差异,这是由于各自生态环境明显不同和长期地理隔离造成的.     

Poly(hydroxyalkanoate) in cyanobacteria: an overview

Abstract In this paper an overview is given on the occurrence of poly(hydroxyalkanoate) (PHA) in cyanobacteria and its possible role as a putative reserve compound. Comparisons are made with the function of other storage compounds that occur in cyanobacteria. For the cyanobacteria Oscillatoria limosa and Gloeothece sp. PCC 6909, some experimental data on the accumulation and mobilization of PHA are presented. O. limosa presumably contains poly(hydroxyvalerate) (PHV), whereas in Gloeothece poly(hydroxybutyrate) (PHB) was detected. Both species accumulated PHA to 6–9% of the dry weight. In Gloeothece PHB accumulation was stimulated by the addition of acetate but in O. limosa this was not the case. PHA was not involved in dark metabolism in either of the strains.     

TAXONOMIC STUDY OF MARINE OSCILLATORIACEAN STRAINS (CYANOBACTERIA) WITH NARROW TRICHOMES. II. NUCLEOTIDE SEQUENCE ANALYSIS OF THE 16S RIBOSOMAL RNA1

Partial 16S ribosomal RNA sequences from five marine oscillatoriacean strains with narrow trichomes were determined by a dideoxynucleotide-termination method. A phenogram was constructed by a distance matrix method including a bootstrap analysis. In addition, a consensus tree was built using cladistic analysis. The results were largely congruent and indicate that the five strains belong to two different lineages. The first lineage groups four phycoerythrin-producing strains with the strain PCC7375 (“Phormidium ectocarpi Gomont”). The second cluster groups strain PCC7105 (“Oscillatoria williamsii Drouet”) with the previously studied strain Microcoleus 10mfx. Comparisons to morphological data are made and the taxonomic level of the separations is estimated.     

发菜PspA基因克隆及其转基因植物的抗旱性分析

为探讨发菜噬菌体休克蛋白A(PspA)的分子信息和基因功能,本研究通过设计特异引物克隆发菜PspA基因,采用qRT-PCR技术,分析发菜PspA基因在干旱胁迫下的表达模式;构建PspA真核表达载体pCAM35 s-GFP-PspA,对PspA进行亚细胞定位和PspA基因拟南芥遗传转化,并对阳性转化拟南芥分别进行Sout...     

培养条件下发菜细胞超微结构的观察

通过观察发菜(Nostoc flagelliforme Born.et Flah.)细胞在不同生长条件的超微结构,探讨细胞的生长和发育特点以及胶质鞘的形成规律。在蒸馏水中浸泡2h后,各种细胞代谢活跃,能进行正常的生长和分裂,其中营养细胞的细胞壁以及一特殊类型的大细胞与胶质鞘的形成有关。在pH7.0的培养液中,出现与胶质鞘有关的细胞结构。在酸性培养液中未见这些结构。在不合适的pH条件下,一特殊类型的小细胞大量增殖。     

« Spirulina labyrinthiformis » Gomont: prima segnalazione nelle Terme di Segesta (Sicilia)

Abstract

First report of the presence of Spirulina labyrinthiformis Gomont in Thermae of Segesta (Sicily). – The study on the algal ecology of thermal waters in Segesta shows for the first time the occurrence of Spirulina labyrinthiformis Gomont. It is interesting to note the high population density of Spirulina against the other components of the algal microflora, represented by the species of Cyanophyceae and Bacillariophyceae and that of photosynthetic bacteria.