Antialgal Activity of Several Cyanobacterial Exometabolites

The isolation of norharmalane (3,4-dihydro-9H-pyrido(3,4-b)indole) from culture media of the cyanobacterium Nodularia harveyana is described. The minimum toxic quantities against selected cyanobacteria of this compound, of the two known cyanobacterial exometabolites 4,4′-dihydroxybiphenyl and norharmane (9H-pyrido(3,4-b)indole) and in addition of harmane (1-methyl-9H-pyrido(3,4-b)indole) were determined using a special TLC plate assay. The three β-carbolines harmane, norharmane and norharmalane were tested both as bases and as hydrochlorides. All four test compounds were found to be cytotoxic against the cyanobacterial test organisms in low quantities (0.5 to 18.0 μg). For the β-carbolines the following structure-response relationships were revealed: the double bond in position 3–4 and possibly the 1-methyl-group increased the cytotoxic effect of these indole alkaloids. Minimum toxic quantities detected for β-carboline bases were in general lower than those of equimolar amounts of the corresponding hydrochlorides. The possible applicability of both β-carbolines and biphenyls as agents in antifouling systems is discussed.     

Selective inhibition of toxic cyanobacteria by β-carboline-containing bacterium Bacillus flexus isolated from Saudi freshwaters

A bacterial strain SSZ01 isolated from a eutrophic lake in Saudi Arabia dominated by cyanobacterial blooms, showed an antialgal activity against cyanobacteria species. Based on the analysis of the 16S rDNA gene sequence, the isolated strain (SSZ01) most likely belonged to the genus Bacillus with a 99% similarity to Bacillus flexus strain EMGA5. The thin layer chromatography (TLC) analysis of the ethyl acetate extract of this bacterium revealed that this strain can produce harmine and norharmane compared to different β-carboline analog standards. Harmine and norharmane were also detected in considerable amounts in bacterial growth medium, indicating a potential excretion of these compounds into the aquatic environment. The crude extract of Bacillus flexus as well as pure materials of harmine and norharmane inhibited the growth of tested species of cyanobacteria. However, the bacterial crude extract has a higher toxicity against tested species of cyanobacteria than harmine and norharmane. In addition, harmine was more toxic to cyanobacteria than norharmane. On the other hand, neither pure compounds of harmine and norharmane nor crude bacterial extract showed any antialgal activity against tested species of green algae. The results of the present study suggest that B. flexus SSZ01 or its crude extract containing harmine and norharmane could be a candidate for the selective control of cyanobacterial blooms without affecting other algal species.     

Antialgal, antibacterial and antifungal activity of two metabolites produced and excreted by cyanobacteria during growth

The antimicrobial activity of two cyanobacterial exometabolites, norharmane (9H-pyrido(3,4-b)indole) and 4,4'-dihydroxybiphenyl, was determined in suspension assays. Good anticyanobacterial activities (concentrations of 8-80 microg ml(-1)) and moderate antibacterial (16-160 microg ml(-1)) and antifungal (32-40 microg ml(-1)) activities were found for both compounds. The natural function as allelopathic chemicals and a possible applicability as antifouling agents or leads for the development of new antifouling chemicals are discussed.     

长白山高山苔原带的亚气生蓝藻

笔者于1981和1933年对氏白山高山苔原带的亚气生蓝藻进行了调查,经鉴定共有4科、8属、11种及两个变种,其中包括1新变种即Chroo-coccus tenax var.minor C.Z.Wang,var.nov.。     

磷和铁对洋河水库螺旋鱼腥藻生长的影响

以有机磷(β-甘油磷酸二钠盐)为磷源, 通过添加的不同营养物质(高浓度铁、厌氧底泥浸出液、微量元素), 比较螺旋鱼腥藻的生长差异, 找寻洋河水库限制螺旋鱼腥藻最大生物量的营养因素, 进而评价磷和铁对螺旋鱼腥藻生长的影响。结果表明:磷和铁同时限制了螺旋鱼腥藻的生长, 且磷的促进作用大于铁;螺旋鱼腥藻在磷浓度为0.1 mg/L, 添加高铁条件下获得最大生物量。添加磷浓度为0.02 mg/L时, 磷和铁之间不存在交互作用;而当添加磷浓度>0.02 mg/L时, 磷和铁之间存在交互作用。而加磷的同时添加厌氧底泥浸出液及微量元素对螺旋鱼腥藻生长则有抑制作用。     

The carotenoids of blue-green algae

The carotenoid compositions of Phormidium persicinum, P. luridum, P. faveolarum and Anabaena flos-aquae have been studied, both quantitatively and qualitatively. β-Carotene is the major carotenoid in all species. The xanthophylls comprise zeaxanthin, echinenone, canthaxanthin and the furanoid mutatochrome. Phormidium persicinum lacks glycosidic carotenoids. Myxoxanthophyll (myxol-2′-rhamnoside) and a 4-ketomyxol-2′-methylpentoside (tentatively 4-keto-myxoxanthophyll) are present in the other species. These distribution patterns are compared with those observed in other blue-green algae and some correlations with taxonomy are apparent.     

大沙河水库冬季浮游植物群落结构与水华分析

于2009年12月、2010年1月和2月对广东省大沙河水库湖泊区距水表层0.5m、5m和10m三个水层的浮游植物进行了定性与定量分析,同时对环境变量进行了测定.采样期间三个月的总降雨量为263mm,水温范围在15.5～19.4℃之间,水体处于混合状态.三次采样中,共检测出浮游植物69种(属),隶属于6个门,浮游植物丰度范围在4.1×10⁶～14.8×10⁶cells·L^-1之间.三个水层的浮游植物优势种类差异不显著(p>0.05),丰度的主要优势种为蓝藻门的卷曲鱼腥藻(Anabaena circinalis)、铜绿微囊藻(Microcystis aeruginosa),这两个种的丰度之和占总丰度的70%以上,在2009年12月和2010年2月的表层出现了轻度鱼腥藻和微囊藻水华.蓝藻自身的浮力调节机制和适应低磷的生活策略是其成为优势种的重要原因,相对稳定的外部条件、水体混合与富营养共同导致的光的可获得性的减少是形成蓝藻水华的关键外部因子.     

Screening of microalgal culture media for the presence of algicidal compounds and isolation and identification of two bioactive metabolites,excreted by the cyanobacteria <Emphasis Type="Italic">Nostoc insulare</Emphasis> and <Emphasis Type="Italic">Nodularia harveyana</Emphasis>

Culture medium extracts obtained from 115 culture media of 35 different microalgae species were screened for the presence of algicidal compounds, in particular for compounds which are cytotoxic to Arthrospira (Spirulina) laxissima. In agar plate diffusion tests and in a test system combining thin layer chromatography (TLC) with the use of an aqueous suspension of living A. laxissima cells as spray reagent, 14 microalgae species were found with cytotoxic activity of different intensity to A. laxissima. In a so-called TLC plate diffusion test, using A. laxissima and other microalgae as test organisms, the culture medium extracts of Nodularia harveyana and Nostoc insulare possessed the highest strength and range of algicidal activity. The algicidal compound in the culture medium extracts of Nodularia harveyana was shown to be norharmane (9H-pyrido(3,4-b)indole), a known indole alkaloid. The main algicidal compound in culture medium extracts of Nostoc insulare was identified as 4,4′-dihydroxybiphenyl. The possible applicability of both compounds as therapeutics or as useful agents for removing cyanobacterial water blooms or for developing new antifouling systems is discussed.     

Malat-dehydrogenase isoenzymbanden als potentielles chemotaxonomisches kriterium für cyanophyceen-species

Malate dehydrogenase isoenzymes from eight cyanophycean species were investigated with polyacrylamide disc gel electrophoresis. Using 7% acrylamide the pherograms from each species showed 5–8 zones with malate dehydrogenase activity. It was demonstrated that in Anabaena flos-aquae there are 8 isoenzyme bands which include 3 forms of equal molecular weight, two of which consist of several isomers differing in their net charge. The MDH zymograms of the blue-green algae investigated can be used as “fingerprints”. The isoenzyme pattern of the MDHs of Anacystis nidulans makes its position in the order Chroococcales uncertain.

Résumé

Wäßrige Extrakte aus acht Cyanophyceenarten wurden einer Polyacrylamid-Discelektrophorese unterzogen und die erhaltenen Elektropherogramme auf Malat-Dehydrogenase (MDH)-Aktivität geprüft. Dabei ergab sich, daß unter unseren Versuchsbedingungen die MDH der getesteten Cyanophyceen in 5–8 Isoenzymbanden aufspaltet. Für Anabaena flos-aquae konnte gezeigt warden, daß sich die 8 Isoenzymbanden auf wenigstens 3 Molekulargewichts-Isomere zurückführen lassen, von denen zwei noch mehrere Ladungsisomere bilden. Die erhaltenen Zymogramme zeigen “fingerprint”-Charakter. was ihre mögliche Verwendbarkeit für die Chemotaxonomie der Cyanophyta nahelegt. Die Stellung von Anacystis nidulans innerhalb der CyanophyceenOrdnungen wird diskutiert.     

黄土丘陵区不同类型生物结皮下的土壤生态化学计量特征

生物结皮在土壤养分累积和循环中起着重要作用.本研究以黄土丘陵区浅色藻结皮、深色藻结皮、藻藓混合结皮、藓结皮、地衣结皮和普通念珠藻结皮6类典型生物结皮为对象,分析不同类型生物结皮土壤碳(C)、氮(N)、磷(P)含量及其化学计量学特征,研究不同类型生物结皮对土壤养分的影响.结果表明:不同类型生物结皮土壤C、N、P、C/N、C/P、N/P差异显著;生物结皮层C、N、P、C/N、C/P、N/P均显著高于0~10 cm土层土壤.6类生物结皮土壤C、N含量均随土层加深而下降,P含量受土层深度影响较小.对于生物结皮层,藓结皮C、N、P含量分别为27.07、2.42、0.67 g·kg^-1,显著高于其他类型生物结皮.念珠藻结皮的0~2 cm土层土壤C、N、P、C/N、C/P、N/P显著高于其他类型生物结皮.     

中国横断山地区蓝藻型肺衣属地衣的三个新种

在形态和化学研究的基础上,结合分子生物学研究方法（ITS片段）,对中国横断山地区的830号与蓝细菌共生的肺衣属标本进行了分类学研究,共发现3个新种;其中,横断山肺衣L. hengduanensis的主要特征是具粉芽化裂芽,无脊肺衣L. irrugulosa的网脊不明显,以及宽叶肺衣L. latilobulata的裂片顶端宽且钝圆;3个种在ITS系统发育树上分别形成独立小枝。文中提供了中国肺衣属中与蓝细菌共生的物种检索表。     

Metal–salt co-tolerance and metal removal by indigenous cyanobacterial strains

Chromium and salt tolerance in five indigenous cyanobacterial strains isolated from contaminated sites was investigated along with their metal bioaccumulative potential. All the five species showed significantly better growth when the medium was spiked with salt or chromium. As compared to single metal or salt treatment, the binary metal–salt (MS) treatments had more favorable effect on cyanobacterial growth as indicated by significantly higher concentration of the primary photosynthetic pigment chlorophyll at M₂₀S₂₀₀₀ (9.9–25.3 μg/mL) as compared to that at M₀S₀ (4.0–12.3 μg/mL). Similarly biomass was much higher at M₂₀S₁₀₀₀ and M₂₀S₂₀₀₀ (41.8–86.2 mg/10 mL) as compared to that at control, M₀S₀ (21.5–36.3 mg/10 mL). Accessory pigments like carotenoids and phycobilinproteins too tended to increase significantly in response to both metal and salts in the two species of Lyngbya (L. putealis and L. ceylanica var. constricta) and Gloeocapsa. These species also showed greater potential of chromium bioaccumulation, which increased further as both salt and metal concentration increased. In the two species of Nostoc however, bioaccumulative potential improve at higher metal concentration, but not affected significantly by salt concentration.     

Properties of Anabaena variabilis cells grown in the presence of diphenylamine

Anabaena variabilis cells have been cultivated in the presence of diphenylamine (12 mg/l) which inhibits the biosynthesis of β-carotene, echinenone and zeasanthin. The content of chlorophyll a is also reduced by diphenylamine. The biosynthesis of myxoxanthophyll is, however, stimulated by this reagent.

The membrane fragments prepared from Anabaena cells grown in the presence of diphenylamine have the activities of both Photosystem 1 (NADP⁺ reduction with DCIP-ascorbate as electron donor) and Photosystem 2 (DCIP reduction with 1,5-diphenylcarbazide as electron donor).

The fluroescence spectra of these cells at 77°K show peaks at 696 and 731 nm and a shoulder around 687 nm. The fluorescence intensity at 687 and 696 nm is higher in these cells than in normal-Anabaena cells.     

Isolation and characterization of norharmane from Reticulitermes termites (Isoptera: Rhinotermitidae)

The fluorescent alkaloid norharmane has been isolated from Reticulitermes termites and characterized by 1H NMR, UV/Vis, mass spectrometry, and gas chromatography/mass spectrometry. Microcoil 1H NMR spectroscopy allowed spectra to be obtained from mass-limited material, facilitating the identification of norharmane, which is the major component in termite fluorescence under UV light. Norharmane was uniformly present at approximately 1 ng/mg in Reticulitermes tibialis Banks workers, soldiers, and alates; Reticulitermes flavipes (Kollar) workers; and Reticulitermes virginicus (Banks) workers. Some termites were observed to fluoresce with less intensity, but no differences in norharmane levels were detected. Mechanisms that may account for fluorescent differences are discussed as are the possible ecological implications of norharmane in termites.     

Isolation and properties of plastocyanin from Anabaena variabilis

Plastocyanin is a copper protein found in photosynethetic tissue and it exhibits the properties of a physiological redox reagent. This protein has been purified from the blue-green alga Anabaena variabilis. Plastocyanin is required for a number of partial reactions of the photosynthetic electron transfer chain. These reactions include the transfer of electrons from reduced 2,3′,6-trichlorophenolindophenol,N,N,N′,N′- tetramethyl-p-phenylenediamine and 2,3,5,6-tetramethyl-p-phenylenediamine to low potential oxidants. Reduced cytochrome c photooxidation does not appear to be dependent on plastocyanin. Cytochrome f, isolated from this alga, will partially replace plastocyanin in many of these reations. Inhibition of photosynthetic reactions by copper chelators appears to occur at some site other than the site of plastocyanin function.     

Poly-beta-hydroxybutyrate accumulation in Nostoc muscorum and Spirulina platensis under phosphate limitation

Nostoc muscorum and Spirulina platensis were grown under phosphate deficiency in order to investigate the role of internal phosphate pool and activity of alkaline phosphatase on poly-β-hydroxybutyrate (PHB) accumulation. PHB accumulation in N. muscorum increased to 22.7% of dry weight (dw) after 4 day of phosphate deficiency, while the internal phosphate pool reduced to the level of 0.02 μM mg dw⁻¹ at a maximum APase activity of 2.57 nM PNP mg dw⁻¹ h⁻¹. In contrary, S. platensis depicted maxima of 1.39 nM PNP mg dw⁻¹ h⁻¹ on day 30 of incubation, which was about 2 fold lower than the observed value of N. muscorum. PHB content in S. platensis remained low even after prolonged phosphate starvation, and a rise only up to 3.5% of dw was recorded on day 60 of phosphate deficiency. Supplementation of NADPH exogenously to S. platensis cultures grown under phosphate deficiency favoured PHB accumulation in 10, 20 and 30 days old cultures, but not in the cultures grown under phosphate deficiency for 60 days. The possible role of phosphate limitation on PHB accumulation is discussed.     

Indole derivatives as neuroprotectants

It seems to be satisfactorily proved that reactive oxygen species (ROS) participate in numerous pathological processes in the nervous system (NS). Compounds able to interfere with the action of ROS might be useful in prevention and treatment of these pathologies. The search is focused on compounds with a suitable spectrum of pharmacological and pharmacokinetic properties, among which indole derivatives are distinct group with great potential to be further developed. The paper presents an overview of indole derived compounds in which protective action has been demonstrated in the NS in situations in which ROS are excessively generated, such as chemically induced oxidative stress, hypoxia/reoxygenation, ischemia/reperfusion. These compounds include indoleamines (melatonin), carbazoles (carvedilol), carbolines (tetrahydrocarbolines, pyrimidoindoles, vinpocetine). Special attention is paid to the gamma-carboline stobadine. A range of effects which seem to be associated with its neuroprotective actions (antioxidant and ROS scavenging effects, capability to pass the hematoencephalic barrier, pharmacokinetic properties, etc.) are considered. A novel compound with pyrimidoindole structure (U-101033E) is mentioned. Attention is drawn also to the neurotoxic potential demonstrated in some carbolines (2-amino-alpha-carboline, halogenated tetrahydro-beta-carboline "TaClo", harmane, norharmane). The indole nucleus seems to be a promising basis for design and synthesis of new derivatives able to protect the NS against oxidative stress in a variety of acute and chronic NS pathologies.     

Cyanobacteria—a potential source of new biologically active substances

Hydrophilic and lipophilic extracts of twelve cyanobacterial strains, isolated from fresh and brackish water, and two waterblooms, collected during the summer from the Baltic Sea, were investigated for their antibiotic activities against seven microorganisms. No inhibitory effects were found against the three Gram-negative bacteria Escherichia coli, Proteus mirabilis and Serratia marcescens and the yeast Candida maltosa. Of all cyanobacterial samples, extracts from seven species inhibited the growth of at least one of the Gram-positive bacteria Micrococcus flavus, Staphylococcus aureus and Bacillus subtilis. M. flavus proved to be the most sensitive bacterium in the agar diffusion test system. In particular, the hexane and dichlormethane extracts showed antimicrobial effects. But only one water extract, prepared from material of a natural waterbloom, was found to be active.     

Ciliates and their picophytoplankton-feeding activity in a high-altitude warm-monomictic saline lake

The impact of feeding on autotrophic picoplankton (APP) on the ciliate composition of the assemblage was surveyed monthly along a depth gradient in the maar crater, athalassohaline, warm monomictic Lake Alchichica (Puebla, Mexico) from June 2003 to December 2005. Numbers of APP were evaluated from their autofluorescence. DAPI staining and the Fluorescently Labeled Bacteria technique were employed to count ciliates and estimate their feeding rates. A total of 38 taxa of ciliates have been identified using Quantitative Protargol Staining. Peritrichs followed by minute spirotrichs (particularly Halteria grandinella) often numerically dominated the ciliate assemblage and emerged as the most efficient APP feeders. A maximum of 54 ciliate cells ml⁻¹ was observed in the surface layer at the end of the mixing period, during the development of diatoms (Cyclotella alchichicana), the cyanobacterial bloom (Nodularia sp.) and its decay. Vorticellids (Pelagovorticella natans, Vorticella sp.) had the highest APP uptake (median 130 APP cil⁻¹ h⁻¹). Mixotrophic Euplotes cf. daidaleos were important APP grazers near the oxycline. Scuticociliates (Cyclidium glaucoma, Uronema nigricans and an anaerobic cf. Isocyclidium globossum), were numerically dominant within the hypolimnetic assemblages and did not ingest APP. Generally, APP were not an important food source for the majority of the ciliate assemblage, being positively selected by a few species during the APP decay in aerobic and microaerobic conditions.     

A light-dependent oxygen-reducing system from Anabaena variabilis

Photosynthetic lamellae from Anabaena variabilis catalyze a vigorous photoreduction of O₂ to H₂O₂. The electrons come to O₂ from an artificial donor, reduced 2,3′,6-trichlorophenolindophenol, and the reaction does not require an exogenous autoxidizable substance. Evidence is presented to show that reduced 2,3′,6-trichlorophenolindophenol can donate electrons at two distinct sites. Photoreduction of O₂ is inhibited by antibodies which block the function of the ferredoxin-reducing substance. The O₂-reducing system may result from the formation of a reduced photoproduct which is more accessible to autoxidation than is the analogous product formed in higher plant chloroplasts.