Effect of Metal Cations on the Viscosity of a Pectin-Like Capsular Polysaccharide from the Cyanobacterium Microcystis flos-aquae C3-40

The properties of purified capsular polysaccharide from the cyanobacterium Microcystis flos-aquae C3-40 were examined by capillary viscometry. Capsule suspensions exhibited similar viscosities between pH 6 and 10 but were more viscous at pH <=4 than at pH 6 to 11. At pH 7, a biphasic effect of metal ion concentration on capsule viscosity was observed: (i) capsule viscosity increased with increasing metal ion concentration until a maximal viscosity occurred at a specific concentration that was a reproducible characteristic of each metal ion, and (ii) the viscosity decreased with further addition of that ion. Because the latter part of the biphasic curve was complicated by additional factors (especially the precipitation or gelation of capsule by divalent metal ions), the effects of various metal chlorides were compared for the former phase in which capsule viscosity increased in the presence of metal ions. Equivalent increases in capsule viscosity were observed with micromolar concentrations of divalent metal ions but only with 10 to 20 times greater concentrations of Na(sup+). The relative abilities of various metal salts to increase capsule viscosity were as follows: CdCl(inf2), Pb(NO(inf3))(inf2), FeCl(inf2) > MnCl(inf2) > CuCl(inf2), CaCl(inf2) >> NaCl. This pattern of metal efficacy resembles known cation influences on the structural integrity of capsule in naturally occurring and cultured M. flos-aquae colonies. The data are the first direct demonstration of an interaction between metal ions and purified M. flos-aquae capsule, which has previously been proposed to play a role in the environmental cycling of certain multivalent metals, especially manganese. The M. flos-aquae capsule and the plant polysaccharide pectin have similar sugar compositions but differ in their relative responses to various metals, suggesting that capsular polysaccharide could be a preferable alternative to pectin for certain biotechnological applications.     

微囊藻碳酸酐酶活性在不同环境因素下的调节与适应

测定了3种微囊藻水华中的优势种类,即铜锈微囊藻（Microcystis aetlzginosa Kutz．）,绿色微囊藻（Microcystis viridis（A．Br．）Lemm）,惠氏微囊藻（Microcystis wesenbergii（Kom．）Kom．）,以及微囊藻573（Microcystis sp．573）的碳酸酐酶活性;研究了无机碳、pH、温度、光强、NIP比等环境因素和外源葡萄糖对铜锈微囊藻碳酸酐酶活性的影响,发现微囊藻碳酸酐酶活性受环境中碳酸氢根浓度的调节,故推断碳酸氢根是铜锈微囊藻利用的主要无机碳形式;相比添加葡萄糖进行混合营养培养的细胞,无外源葡萄糖和暗饥饿培养的微囊藻细胞会产生高约6倍的碳酸酐酶活性;光强的改变也会影响碳酸酐酶的活性。     

Taxonomic notes on water bloom forming Microcystis species (Cyanophyta) from China—An example from samples of the Dianchi Lake

Ten common species of Microcystis, based on the examination of water samples from the Dianchi Lake, Yunnan, China, were morphologically described, and their taxonomy was also discussed. They are Microcystis aeruginosa, M. botrys, M. firma, M. flos-aquae, M. ichthyoblabe, M. novacekii, M. pseudofilamentosa, M. smithii, M. viridis and M. wesenbergii. Taxonomic status of other Microcystis species reported in China was also evaluated. Key words Cyanophyta, Microcystis, morphology, taxonomy, China.     

中国淡水微囊藻属常见种类的分类学讨论——以滇池为例

根据中国云南滇池藻类样品的观察结果,对中国分布的淡水微囊藻属Microcystis10个常见种的形态特征进行了描述,同时对它们的分类学进行了讨论,并整理出分类检索表。这10种微囊藻是铜绿微囊藻M.aeruginosa、放射微囊藻M.botrys、坚实微囊藻M.firma、水华微囊藻M.flos-aquae、鱼害微囊藻M.ichthyoblabe、挪氏微囊藻M.novacekii、假丝微囊藻M.pseudofilamentosa、史密斯微囊藻M.smithii、绿色微囊藻M.viridis、惠氏微囊藻M.wesenbergii。最后还讨论了中国报道的其它微囊藻种类的分类学状况。     

Phylogenetic Inference of Colony Isolates Comprising Seasonal Microcystis Blooms in Lake Taihu, China

Blooms of the toxin-producing cyanobacterium, Microcystis spp., are an increasingly prevalent water quality problem and health hazard worldwide. China's third largest lake, Lake Taihu, has been experiencing progressively more severe Microcystis blooms over the past three decades. In 2009 and 2010, individual Microcystis colonies, consisting of four different morphospecies, were isolated and genotyped using a whole-cell multiplex PCR assay. The 16S-23S rDNA-ITS sequences were aligned based on Bayesian inference and indicated that one morphospecies was genetically unique (Microcystis wesenbergii) and three were indistinguishable (Microcystis aeruginosa, Microcystis flos-aquae, and Microcystis ichthyoblabe). Microcystin (mcyB) genes were detected intermittently in two of the morphospecies while the other two morphospecies lacked the mcyB gene in all samples. Water temperature was found to influence bloom formation and morphotype prevalence, and chlorophyll a and temperature were positively and significantly correlated with microcystin concentration. Cooler water temperatures promoted toxigenic strains of Microcystis. Wind appeared to influence the distribution of morphotypes across the lake, with M. aeruginosa and M. ichthyoblabe being more susceptible to wind stress than M. wesenbergii and M. flos-aquae. The results of this study indicated that the blooms were composed of a variety of Microcystis morphospecies, with more genotypes observed than can be attributed to individual morphotypes. We conclude that morphology is not a reliable indicator of toxigenicity in Lake Taihu, and caution should be exercised when the M. aeruginosa morphotype is present because it is capable of producing MC-LR, the most toxic microcystin isoform.     

东湖蓝藻水华毒性的研究 Ⅱ.季节变化及微囊藻的毒性

1984年至1986年间武汉东湖(包括湖边池塘)的水华有7种,即铜绿微囊藻、大型铜绿微囊藻、边缘微囊藻、水华鱼腥藻、卷曲鱼腥藻、美丽颤藻和束丝藻。经生物测定,除束丝藻未测、卷曲鱼腥藻和美丽颤藻未测出毒性外,其余4种皆为有毒水华。东湖的水华随着季节变化而有不同类型的更迭,其出现格局为:卷曲鱼腥藻、微囊藻、颤藻、微囊藻。微囊藻水华的毒性在不同季节也有较大差异,毒性最低在8—9月份,最高在12月份(LD_(50)=24mg/kg鼠重),随着温度的降低而提高。讨论了某些环境参数与微囊藻水华形成及其毒性变化的关系。此外,还用脑内注射和腹腔注射方法,研究了微囊藻毒素的毒性表现。     

Occurrence of isopropylthio compounds in the aquatic ecosystem (Lake Neusiedl, Austria) as a chemical marker for Microcystis flos-aquae

Abstract Volatile organic sulfur compounds occuring during a bloom of different species of Microcystis in Lake Neusiedl, Austria, were analyzed by gas chromatography and mass spectrometry. In open water diisopropyl disulfide and diisopropyl tri-sulfide were the only sulphur compounds to be found. It was shown that Microcystis flos-aquae was the causative agent for the generation of these sulphur compounds, since high concentrations of these substances were found both in the floating scum of cyanobacteria taken from open lake and in axenic cultures of five isolated strains of M. flos-aquae . Strains isolated from colonies of Microcystis aeruginosa were not able to synthesize isopropylthio compounds. Alternatively, methylthio compounds were released. The rather unusual formation of the isopropylthio group can be used as a chemical marker to differentiate between M. flos-aquae and M. aeruginosa as two separate species which hitherto have been regarded as formae. In a canal passing through the reed belt of Lake Neusiedl where Microcystis was missing, these compounds were not detected. Different sulfur compounds (dimethyl disulfide, dimethyl trisulfide, dibutyl sulfide and bis(methylthio) methane) which in part have not yet been reported for freshwater ecosystems occurred at this site. Their origin, however, remains obscure.     

PROPERTIES OF MICROCYSTIS AERUGINOSA AND M. FLOS-AQUAE (CYANOPHYTA) IN CULTURE: TAXONOMIC IMPLICATIONS1

Cultures were cloned from a sample containing Microcystis aeruginosa, M. flos-aquae and a few morphological intermediates. The M. aeruginosa cultures remained distinct from the M. flos-aquae cultures in (a) cell size, (b) cell aggregation pattern, (c) width of the mucilage surrounding the multicellular colonies, (d) sharpness of the mucilage boundary, (e) efect of 0.1–1.0 μM calcium chloride on the disaggregation of multicellular colonies, (f) frequency of mucilage mutants and (g) colony morphology on agar media. No M. flos-aquae culture produced morphs resembling M. aeruginosa, inconsistent with proposals that M. flos-aquae is a developmental stage or environmentally-induced variant of M. aeruginosa. After longterm cultivation, but not soon after origanal isolation, several M. aeruginosa cultures contained mutants with diminished mucilage production and an altered colony shape.     

NaNO3胁迫对两种微囊藻VOCs释放的影响

为了揭示硝酸盐过量积累对藻类产生胁迫后对藻类挥发性有机化合物(VOCs)释放以及水体气味的影响, 研究以形成蓝藻水华的主要种类铜绿微囊藻和水华微囊藻为材料, 在NaNO3胁迫下, 对其细胞生长和释放的VOCs进行测定分析。结果表明, NaNO3胁迫24h后, 铜绿微囊藻和水华微囊藻细胞生长均受到明显影响, 与对照相比细胞密度分别降低了29.6%和43.0%。在正常条件下, 铜绿微囊藻和水华微囊藻分别释放出26和27种化合物, 其主要类型是硫化物、烃类、萜烯类、苯类、醛类和酯类化合物。在NaNO3胁迫下, VOCs含量均明显增加, 其中铜绿微囊藻释放的此6类VOCs含量分别增加了60.5%、14.3%、136.6%、92.1%、730.0%和120.7%, 水华微囊分别增加了172.7%、162.5%、154.0%、55.9%、51.2%和109.4%。此外, 铜绿微囊藻VOCs中出现4种新成分, 水华微囊藻VOCs中出现1种新成分。由此可见, 硝酸盐过量积累对藻细胞产生胁迫后会诱导其释放出大量VOCs, 从而增加水体气味、破坏水质。       

The effects of barley straw (Hordeum vulgare) on the growth of freshwater algae

Bioassays were conducted to determine the efficacy of barley straw liquor in controlling algal growth of 12 freshwater species of algae representing three divisions. Barley straw liquor inhibited the growth of three nuisance algae common in freshwater: Synura petersenii, Dinobyron sp., and Microcystis aeruginosa. However, Selenastrum capricornutum, Spirogyra sp., Oscillatoria lutea var. contorta, and Navicula sp. had significantly increased growth in the presence of straw liquor. The growth of the remainder, Ulothrix fimbriata, Scenedesmus quadricauda, Chlorella vulgaris, Anabaena flos-aquae, and Synedra sp. showed no significant difference from controls. In a related field study, we treated four of six ponds with barley straw and monitored their chlorophyll a levels for one growing season. While phytoplankton populations in all ponds decreased in midsummer, the phytoplankton biomass in treated ponds did not differ significantly from that of control ponds, suggesting that the application of barley straw had no effect on algal growth in these systems.     

STRONG PROBABILITY OF LETHAL TOXICITY IN THE BLUE-GREEN ALGA MICROCYSTIS VIRIDIS LEMMERMANN1

Lethal toxicity (intraperitoneal, mouse) was examined in relation to Species composition of samples containing bloom-forming Microcystis populations from natural waters and correlated with toxicity of laboratory strains of four Microcystis formas and species. Toxicity was not always associated with the presence of M. aeruginosa f . aeruginosa Elenkin. A sample with almost all cells of M. aeruginosa f . aeruginosa showed no toxicity, However samples comprised of a high percentage of M. viridis Lemmermann often showed lethal toxicity. Toxicity tests were done on culture strains M. aeruginosa f aeruginosa, M. aeruginosa f flos-aquae Elenkin , M. viridis and M. wesenbergii Kamárek. All five cultured strains of M. viridis were found to be toxic, while only one out of nine strains of M. aeruginosa f . aeruginosa was toxic. Six strains of M. wesenbergii showed no toxicity, It is recommended that attention should be paid to the occurrences and possibility of toxic bloom of M. viridis from the standpoint of water management and public health .     

微囊藻群体细胞数量估算的一种简单方法

采用加酸水解和人工计数的方法,对巢湖铜绿微囊藻、放射微囊藻、惠氏微囊藻、坚实微囊藻、绿色微囊藻、挪氏微囊藻、水华微囊藻、鱼害微囊藻所含细胞数进行了估算.通过统计分析,建立了微囊藻群体最大投影面积与所含细胞数的回归方程模型,通过这些模型可以估算群体微囊藻所含的细胞数.     

Modulation and adaptation of carbonic anhydrase activity in Microcystis spp. under different environmental factors

The carbonic anhydrase (CA) activities were determined in three cyanobacterial species, namely Microcystis aeruginosa Kütz., Microcystis viridis (A.Br.) Lemm, and Microcystis wesenbergii (Kom.) Kom, which were dominant in a lake (Dianchi Lake) subject to major blooms. In more detailed experiments on M. aeruginosa, the effects of inorganic carbon, pH, temperature, nitrogen/phosphorus ratio, glucose, and light intensity on CA activity were also investigated. Because of the relatively alkaline pH value of the culture media for the optimum growth of algal cells, bicarbonate ions were the main form of exogenous inorganic carbon. The results showed that the CA activity of M. aeruginosa was influenced dramatically by the concentration of bicarbonate. Consequently, it was suggested that bicarbonate ions were the main form of exogenous inorganic carbon that M. aeruginosa could utilize. Cultures grown in the dark exhibited CA activity six times higher than that of cells cultured mixotrophically with the addition of glucose. Features of eutrophic water bodies promoted an increase in CA activity, and the resulting higher CA activity would accelerate the utilization of inorganic carbon and favor the growth and blooming of Microcystis spp. in eutrophic lakes. Although the experiments were carried out under controlled experimental conditions, they could provide some basic data that would prove useful for the control of cyanobacterial blooms in nature.     

三种水华蓝藻对不同磷浓度生理响应的比较研究

本实验研究了铜绿微囊藻(Microcystis aeruginosa FACHB469)、水华鱼腥藻(Anabaena flos-aquae FACHB245)和浮游颤藻(Oscillatoria planctonicaFACHB708)对磷浓度变化的生理响应。结果表明,在缺磷条件下,A. flos-aquae对低磷环境的适应能力较强,O. planctonica其次,M. aeruginosa最差;在磷充足条件,微囊藻对磷过量吸收的能力明显高于其他两种蓝藻。三种蓝藻胞外碱性磷酸酶活性(APA)与培养基中磷浓度呈负相关性,其产生碱性磷酸酶(AP)的能力由高至低为:A. flos-aquae>O. planctonica>M. aeruginosa。磷缺陷时A. flos-aquae产生的胞外APA约是M. aeruginosa的10倍,是O. planctonica的5倍。     

阴离子表面活性剂LAS对产毒和无毒微囊藻生长及产毒特性的影响

文章研究了低浓度范围内不同浓度梯度的阴离子表面活性剂直链烷基苯磺酸盐(LAS)对产毒微囊藻(Microcystis aeruginosa, FACHB905)和无毒微囊藻(Microcystis wesenbergii, FACHB908)生长、光合特性、种间竞争及毒素合成的影响。结果表明,在0.05—5.0 mg/L LAS浓度梯度处理下,产毒微囊藻的生物量、产毒基因mcyD表达量和每细胞MCs含量均在培养12d后显著增加。产毒微囊藻胞内和胞外MCs含量在各LAS浓度处理后分别为0.069、0.052、0.061、0.038和0.037 fg/fg Chl.a及107.1、103.7、127.1、99.6和113.7 ng/L。即使在0.5 mg/L低浓度LAS处理条件下,上述3个参数也分别比对照组显著增加了24.2%、12.4倍和10.4%。浓度为0—0.2 mg/L LAS对无毒微囊藻的生物量无明显影响,而较高浓度的LAS(0.5—5.0 mg/L)明显抑制了无毒微囊藻的生长。在两株微囊藻混合培养时, 0.2—1.0 mg/L LAS处理组的产毒铜绿微囊藻mcy D的表达对LAS...     

绿藻栅藻对微囊藻的抑制效应及评价

为筛选具有控制微囊藻水华潜力的绿藻, 研究基于藻类之间的化感作用, 对34株绿藻开展筛选及评价工作。结果发现, 栅藻FACHB-1229的抑制率最高, 其滤液对微囊藻FACHB-3550和FACHB-905的抑制率分别为53.95%和48.39%; 通过对滤液中的物质进行GC-MS检测, 推测该藻株的效应物质可能为邻苯二甲酸二(2-甲氧基乙基)酯。进一步对FACHB-1229生长和光合放氧、氨氮耐受等指标进行评价, 结果发现: 该藻株在孔板中的生长速率(0.38±0.06)/d高于微囊藻生长速率(0.13±0.03)/d; 栅藻FACHB-1229的光合放氧速率高于同期测定的其他绿藻光合放氧速率, 可达(229.91±10.49) μmol O₂/(mg Chl.a·h); 同时该藻株对氨氮的耐受能力最强, 在氨氮浓度为1888.60 mg/L时其生长速率可达(0.30±0.08)/d。此外, 在与微囊藻FACHB-3550进行共培养时, 栅藻FACHB-1229所占比例持续升高。综上, 栅藻FACHB-1229具备与微囊藻竞争的优势, 有望成为微囊藻水华生物控制的优选材料。     

铜绿微囊藻对紫外辐射的生理代谢响应

采用紫外(UV)滤膜过滤日光UV以及紫外灯添加UV的方法,研究了UV辐射对铜绿微囊藻Microcystis aeruginosa单细胞藻株PCC7806和群体藻XW01生长及生理代谢的影响。结果显示,在室内条件下低剂量UV辐射可促进群体微囊藻XW01生长;室外条件下与滤除了UV的光照相比,含有UV的完全日光更有利于微囊藻生长;而相同的UV辐射强度均导致单细胞株死亡,群体株显示了较强的UV抗性;日光中的UV可促进XW01合成抗氧化相关的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)、促进胞外多糖的产生并形成较大的群体、促进UV屏障物质类菌孢素氨基酸(MAAs)和伪枝藻素(Scy)积累。这些生理代谢的改变,消除了阳光辐射中UV对微囊藻的伤害。研究的结果提示,自然条件下阳光中的UV有助于群体微囊藻生长。     

A novel method for increasing the frequency of somatic embryogenesis in wheat tissue culture by NaCl and KCl supplementation

The effect of NaCl, KCl and LiCl on the growth and morphogeneis of tissue cultures originating from immature embryos of four wheat (Triticum aestivum L.) and one triticale (Triticosecale)varieties was investigated. The morphogenetic pathway to plant regeneration in Chinese Spring wheat was determined as incomplete somatic embryogenesis because the differentiation and subsequent germination of the shoot apices happened in the early phase of embryo development. Culture medium supplemented by NaCl suppressed the differentiation of shoot apices resulting in the development of more typical somatic embryoids. Forty mM concentrations of both NaCl or KCl increased the formation of somatic embryos in Chinese Spring. Arthur and GK Kincso wheat varieties while Lasko triticale regenerated well without the addition. The salts inhibited plantlet formation from somatic embryoids so the salts supplement should be omitted. Forty mM LiCl inhibited growth while 10mM LiCl had no effect on growth or embryogenesis.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - MS Murashige and Skoog (1962) medium     

Simultaneous cultivation of Spirulina platensis and the toxigenic cyanobacteria Microcystis aeruginosa

Mangueira Lagoon, located in the extreme south of Brazil, has water with physicochemical characteristics such as alkaline pH and carbonate levels propitious for the growth of the cyanobacterium Spirulina platensis. Previously published studies have shown that Mangueira Lagoon water supplemented with small quantities of carbon and nitrogen is suitable for S. platensis cultivation and can significantly reduce production costs. We studied mixed cultures of Spirulina platensis and the toxic cyanobacterium Microcystis aeruginosa using a 2(3) factorial design in which the three factors were the initial biomass concentration of S. platensis and M. aeruginosa and the type of culture medium (100% Zarrouk's medium or 80% Mangueira Lagoon water plus 20% Zarrouk's medium). The highest S. platensis maximum specific growth rate (mu(max)) occurred in the culture with the highest M. aeruginosa biomass concentration and when undiluted culture medium was used (micro(max) = 0.283 d(-1)). The highest M. aeruginosa specific death rate (k) was obtained in the presence of S. platensis (k = 0.555 d(-1)) and was independent of the initial M. aeruginosa biomass concentration and culture medium, demonstrating that S. platensis cultures are not susceptible to contamination by M. aeruginosa. The culture medium had no significant influence (p > 0.05) on S. platensis micro(max) values, indicating that production costs could be reduced by using a medium consisting of 80% Mangueira Lagoon water plus 20% Zarrouk's medium.     

Growth inhibition of bloom-forming cyanobacterium Microcystis aeruginosa by rice straw extract

AIMS: To inhibit the growth of the bloom-forming cyanobacterium Microcystis aeruginosa using a rice straw extract. METHODS AND RESULTS: The cell numbers of the algal strain M. aeruginosa UTEX 2388 significantly decreased after treatment with different concentrations (0.01, 0.1, 1 and 10 mg l(-1)) of a rice straw extract for an 8-day cultivation period. Among seven tested allelochemicals from rice straw, salicylic acid at 0.1 mg l(1) exhibited the highest allelopathic activity (26%) on day 8. A synergistic effect on algal growth inhibition was found when adding two or three phenolic compounds from the rice straw. CONCLUSIONS: The growth of M. aeruginosa was inhibited by rice straw extract concentrations ranging from 0.01 to 10 mg l(1). This activity was due to the synergistic effects of various phenolic compounds in the rice straw. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of rice straw as an effective material for the growth inhibition of M. aeruginosa implies it may have the potential to be used as an environment-friendly biomaterial for controlling the algal bloom of M. aeruginosa in eutrophic water.