Membrane Lipids and Their Fatty Acid Composition in Nostoc flagelliforme Cells

Nostoc flagelliforme Born. et Flah is highly adapted to drought stress, cold and light stresses, and suitable for growing in the unfavorable areas. This paper presents the results of the analysis of the membrane (mainly thylakoid membrane) lipids from N. flagelliforme in order to investigate the relationship between membrane lipid composition and stress resistance to this cyanobacteria. The membrane lipids are composed of monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG). The major fatty acids in these lipids are palmitic (16∶0), palmitoleic (16∶1), stearic (18∶0), oleic (18∶1), linoleic (18∶2) and linolenic (18∶3) acids. In N. flagelliforme , polyunsaturated fatty acids account for 73% of the total fatty acids, much higher than that of the other cyanobacteria reported so far. Among which 16∶1 and 18∶3 are as high as 28.9% and 34.3% respectively. The high resistance of N. flagelliforme to abnormal conditions may be associated with the extent of unsaturation of fatty acids. In addition, the wild N. flagelliforme treated with water for 30 min and cultured for 24 h and the lipid and fatty acid composition were found to be not affected by water_absorption.

ULTRASTRUCTURE OF THE VEGETATIVE CELLS OF NOSTOC FLAGELLIFORME PREPARED WITH HIGH PRESSURE FREEZING AND FREEZE SUBSTITUTION TECHNIQUE

The ultrastructure of the vegetative cells of Nostoc flagelliforme Born. et Flah. was investigated with high pressure freezing and freeze substitution technique and compared with the results obtained by using conventional preparation methods. During the processes of chemical fixation, dehydration and embedding, the cell structures might be more artificially modified than that obtained from high pressure freezing and freeze substitution. With the present method, the sheath of N. flagelliforme could be well penetrated and no extra big space could exist between the cell and the sheath. The cell protoplasm rarely shrinked. Some fine structures of cell inclusions and unit membranes became visualized. Many bacteria were harbored in the sheath. In addition, the presence of big vacuoles in the cell of N. flagelliforme as well as the presence of bacteria in the sheath shown in the present preparation for cyanobacteria has not been described so far in the literature.

发菜(Nostoc flagelliforme)培养条件的研究

研究了光照强度、日供水次数、CO2浓度和培养基成分对发菜生长的影响。结果显示,中度光强(114μmol.m-2.s-1)下发菜生长最快;发菜的生长基本同供水次数成正相关系;CO2浓度的升高并没有显著促进发菜生长,低光条件下(57μmol.m-2.s-1),高浓度的CO2(2800μL/L)抑制了发菜的生长;用BG11培养的发菜生物量的增长显著高于用BG110培养的;BG11培养基中K+和CO32-的缺失并没有显著影响发菜的生长。

Effects of Lanthanum on Liquid Culture and Contents of Amino Acids ofNostoc Commune Flagelliforme Cells

The effects of La(NO3)(3) on the liquid culture and the contents of amino acids of Nostoc commune flagelliforme cells were studied. It is indicated from the experimental results that the growth of Nostoc commune flagelliforme cells can be stimulated by La(NO3)(3) at the concentrations from 1 to 200 mg.L-1, and among them the treatment of 100 mg.L-1 La(NO3)(3) has the largest A(670) and dry weight which increased by 64.9% and 61.1%, respectively as compared with the control, and La(NO3)(3) can also influence the contents of some kinds of amino acids in Nostoc commune flagelliforme cells. The contents of aspartic acid and glutamic acid decreased by 59.9% and 57.9%, respectively, and that of proline increased by 24.5% with the treatment of 200 mg.L-1 La(NO3)(3).

Characterization of Corrinoid Compounds in the Edible Cyanobacterium <i>Nostoc flagelliforme</i>the Hair Vegetable

Vitamin B12 contents in the edible cyanobacterium Nostoc flagelliforme, also known as hair vegetable, were assayed using a microbiological method. We detected high vitamin B12 contents in samples of naturally grown cells (109.2 ± 18.5 μg/100g dry weight) and cultured cells (120.2 ± 53.6 μg/100g dry weight). However, commercially available hair vegetable samples, which comprised fake substitutes and Nostoc, had variable contents (4.8 - 101.6 μg/100g dry weight) because concomitant fake items contain very low vitamin B12 contents. To evaluate whether natural and cultured N. flagelliforme samples contained vitamin B12 or pseudovitamin B12, corrinoid compounds were purified and identified as pseudovitamin B12 (approximately 72%) and vitamin B12 (approximately 28%) using silica gel 60 TLC bioautography and LC/MS. The results suggested that N. flagelliforme contains substantial amounts of pseudovitamin B12, which is inactive in humans.

The inhibition of Typhonium flagelliforme Lodd. Blume leaf extract on COX-2 expression of Wi Dr colon cancer cells

Objective: To determine the inhibition activity of Typhonium flagelliforme Lodd. Blume(T. flagelliforme) leaf extract on cyclooxygenase 2(COX-2) expression of colon cancer cells.Methods: T. flagelliforme leaf extract was prepared to macerate in ethyl acetate. In vitro anticancer activity was assayed by MTT method on Wi Dr colon cancer cells. This study applied apoptosis induction assay to investigate the mechanism of cell death using double staining method. COX-2 expression was stained by immunocytochemistry.Results: T. flagelliforme showed anticancer activity and induced apoptosis on Wi Dr cells through inhibition of COX-2 expression with IC5070 mg/m L.Conclusions: This study showed that T. flagelliforme is a promising chemopreventive agent for colon cancer through COX-2 inhibition.

The effects of different strength of MS media in solid and liquid media on in vitro growth of Typhonium flagelliforme

Objective: To determine the effects of different strength of Murashige and Skoog(MS)media(full,1/2and1/4) in solid and liquid media on in vitro growth of Typhonium flagelliforme(T. flagelliforme), whereby an optimum media composition can be provided for mass propagation of T. flagelliforme.Methods: Rhizome bud of T. flagelliforme was obtained from the axenic in vitro established T. flagelliforme plantlets in Plant Tissue Culture Laboratory, Universiti Teknologi MARA, Shah Alam. Rhizome bud was used as explant and cultured onto shoot proliferation medium under different strength of MS media(full,1/2,1/4) in solid and liquid culture media.Results: After 6 weeks of culture, the number of shoot, number of leaf, number of root,height of shoot, fresh weight, dry weight and chlorophyll content of T. flagelliforme were analyzed. A comparison was made between liquid and solid culture media. The results revealed that the liquid culture media were more effective for all the growth parameters(shoot height, shoot number, leaf number, root number, fresh weight, dry weight, chlorophyll a and chlorophyll b content) compared to solid culture media. Apart from that,this study revealed the positive relationship between strength of MS media and type of culture media(solid and liquid media) to the growth of T. flagelliforme. Growth of T. flagelliforme was improved when MS strength was increased in liquid media. In contrast, growth of T. flagelliforme was improved when MS strength was decreased in solid media.Conclusions: Through this study, an optimum media composition for mass propagation of T. flagelliforme had been established by observing effects of MS media strength and type of culture media(solid and liquid media) on the growth of T. flagelliforme.

Nostoc commune Vauch. polysaccharide alleviates Pb-induced hepatorenal toxicity by changing gut bacteriome, mycobiome, and metabolome

This study aimed to explore the protective effect and potential mechanism of Nostoc commune Vauch.polysaccharide(NCVP)on lead(Pb)-poisoning mice.NCVP improved Pb-induced hepatorenal toxicity and inflammatory responses and modulated key indicators of antioxidant capacity.Moreover,the down-regulation of critical proteins of the Nrf2 pathway induced by Pb could be reversed after NCVP intervention.In addition,NCVP maintained the diversity of gut bacteriobiota and restored the relative abundance of f_Prevotellaceae,g_Alloprevotella,and f_Eubacterium_coprostanoligenes_group reduced by Pb.Also,NCVP regulated the diversity and abundance of gut mycobiota affected by Pb.Specifically,Pb decreased the proportion of pathogenic species(g_Fusarium,p_Basidiomycota,g_Alternaria,g_Aspergillus,and g_Candida)while NCVP increased the abundance of probiotics species(g_Kazachstania and p_Ascomycota).Furthermore,the metabolomic analysis found that NCVP significantly altered a range of microbial metabolites,including porphobilinogen,cromakalim,salidroside,and trichostatin A,which has significant associations with specific gut bacteriobiota or mycobiota.These altered metabolites are involved in primary bile acid biosynthesis,metabolism of xenobiotics by cytochrome P450,lysine degradation,and other metabolic pathways.Overall,our findings indicate that NCVP might be an excellent natural product for eliminating Pb-induced hepatorenal toxicity,possibly by regulating gut bacteriome,mycobiome and metabolome.

乙酰胺对念珠藻Nostoc 106生长周期的影响

研究了不同浓度的乙酰胺对念珠藻106(Nostoc sp.106)在对数期、稳定期和生长末期的影响。研究结果表明加入一定浓度的乙酰胺对蓝藻生长有一定的刺激作用。测定叶绿素a、藻胆蛋白含量、SOD含量、ATP含量等生长代谢指标,表明加入浓度为1、2和5 mg/m L的乙酰胺不同程度地延缓了念珠藻Nostoc sp.106的衰亡,浓度5 mg/m L的乙酰胺增加了念珠藻Nostoc sp.106在生长对数期的时间。

Ca^(2+)对普通念珠藻(Nostoc commune Vanch.)生长影响的试验

对普通念珠藻(NostoccommuneVanch.)进行了生长条件的探索研究。初步研究结果表明:普通念珠藻的生长需要最适光照强度为2200lux左右,最适温度25℃,生长最适点pH=8;在0.02%的Ca2+浓度下的生长状况最好。

普通念珠藻(Nostoc commune Vauch.)藻蓝蛋白的提取

[目的]为普通念珠藻藻蓝蛋白的提取及开发提供试验及理论基础。[方法]以普通念珠藻为材料，比较藻体及细胞的破碎方法、提取液类型及饱和硫酸铵浓度对藻蓝蛋白提取的影响。[结果]结果表明：利用发酵法破碎藻体和细胞，0．05mol／L的KP缓冲液（pH值7．2）作为提取液，经过30％～50％饱和硫酸铵盐析和DEAE-Toyopeal 650 S离子交换柱层析后，藻蓝蛋白纯度达2．51，最大紫外-可见吸收峰位于616nm。[结论]普通念珠藻藻蓝蛋白分离提取较为理想的程序为：藻籼→0.05mol／L KP缓冲液（pH值7．2）浸泡→发酵法破碎细胞→35％～50％饱和硫酸铵盐析→DFAE-Toyopeal 650 S柱层析→较纯的藻蓝蛋白。

Obsevation for Epidermal Ultrastructure of Nostoc sphaeroides Kutzing under Scanning Electron Microscope

[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.

固氮蓝藻Nostoc commune和Anabaena azotica Ley耐盐性及机理研究

文章考察了两种固氮蓝藻Nostoc commune（地木耳）和Anabaena azotica Ley（固氮鱼腥藻）在不同浓度Na2CO3（0.2×10^-4～1.8×10^-4g/m l）的BG110培养基中的耐盐性。分别测定了两种固氮蓝藻在不同培养阶段的叶绿素a含量、胞外多糖含量、氨基酸含量和固氮酶活性的变化。研究结果表明两种固氮蓝藻都能在Na2CO3盐胁迫条件下生长,且随着Na2CO3盐胁迫性增加,两种蓝藻的叶绿素a含量、胞外多糖含量、氨基酸含量和固氮酶活性都呈现先增加后减少的趋势;而随着培养天数的增加,两种藻类叶绿素a的变化曲线与微生物的生长曲线很相似,胞外多糖和氨基酸的增长和叶绿素a的增长是同步的,其中,Anabaena azotica Ley的固氮酶活性在培养到21天时达到最大值,Nostoc commune的固氮酶活性在培养到28天时达到最大值;比较而言Anabaena azotica Ley的耐盐性好于Nostoc commune的耐盐性,固氮能力也高于Nostoc commune。

双方向氢酶在Gunnera/Nostoc固氮共生体存在的证据

结果表明:在Gunnera/Nostoc固氮共生体中存在有双方向氢酶,即此酶既可催化组织放H_2,又可催化氢的吸收利用。双方向氢酶的存在,对Gunnera/Nostoc固氮共生体而言是十分有利的,因此酶使固氮酶在固氮过程中具有了适应变化着的还原力供应状况(碳水化合物不足)及氧气环境变化的能力。

碳水化合物和H_2对Gunnera／Nostoc共生体固氮活力的影响

以Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体为材料，研究、比较了碳水化合物和Ｈ２对其固氮活力及呼吸速率的影响，结果表明，在正常条件下，外源Ｈ２可提高Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮活力近１００％，却使其呼吸速率下降近５０％；而碳水化合物（葡萄糖）也可使其固氮活力提高约１００％，并使其呼吸速率提高近１６０％。表明碳水化合物及Ｈ２均可为Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体提供固氮过程的还原力。由于Ｈ２的循环利用降低了呼吸速率，所以就间接地节约了Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮过程中对碳水化合物的消耗。结果还表明，碳水化合物（葡萄糖）对恢复饥饿后的Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮活力的作用优于外源Ｈ２。

SECONDARY METABOLITES OF CYANOBACTERIA NOSTOC SP

Cyanobacteria attracted much attention recently because of their secondary metaboliteswith potent biological activities and unusual structures. This paper reviews some recent studies on the iso-lation, structural, elucidation and biological activities of the bioactive compounds from cyanobacteriaNostoc species.

Comparison of the Photosynthetic Characteristics of Two Developmental Stages in Nostoc sphaeroides Kützing (Cyanophyta)

The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.

Compatible Solutes in the Akinetes of the Terrestrial Cyanobacterium <i>Nostoc</i>sp. HK-01 Contribute to Its Heat Tolerance

The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several other organisms. The dormant cells, called akinetes, of the terrestrial cyanobacterium Nostoc sp. HK-01 can revive after dry heat exposure at 100℃ for more than 10 h. We investigated the compatible solutes that protect the biomolecules in Nostoc sp. HK-01 akinetes using colonies containing various proportions of akinetes. We extracted the intracellular substances from each colony with 80% ethanol, which we purified with a series of analytical columns and analyzed by high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry. The compatible solutes were screened for their ability to prevent protein aggregation upon heating using the model enzyme lactate dehydrogenase. We detected an accumulation of glucosylglycerol, betaine, and glycine in akinetes. In addition, we confirmed that betaine, glycine, sucrose, and trehalose contributed to the prevention of the protein aggregation. The levels of sucrose and glycine in the colonies were approximately 1000× higher than those of glucosylglycerol, betaine, or trehalose. Our results indicated that sucrose and glycine are the main compatible solutes in the hydrophilic fractions of the cell extracts of Nostoc sp. HK-01 akinetes.

Isolation and Characterization of Cyanobacterial Community Including a Microcystin-Producing Nostoc sp. Strain in the Nile River, Egypt

The combined use of morphological identification and phylogenetic characterization employing primers that target the 16S rDNA region led to the identification of ten isolates belonging to eight cyanobacterial genera in the Nile River. 16S-23S ITS region was amplified to confirm two isolates to be affiliated to genus Nostoc. Using MALDI-TOF/MS, we detected the production of the hepatotoxic demethylated MC-LR by one isolate that clustered together with the genus Nostoc. Protein phosphatase inhibition assay has confirmed toxicity. Our results add to the rising importance of Nostoc as a hepatotoxin-producing cyanobacterium. Furthermore, our results stress that water municipalities in the studied region need to assess the potential threat of toxic cyanobacteria that may pose to human health and economy.

葡萄糖和氢对Gunnera／Nostoc固氮共生体固氮活力的影响

Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ固氮共生体固氮相对效率（ＲＥ）可在０．２６～０．８０之间变动，而不是一个常数。外加１．５％葡萄糖液可使其固氮活力提高约１００％，同时也使组织的呼吸速率提高了近１６０％。加外源Ｈ２可使其固氮活力提高近１００％，但却使组织的呼吸速率降低了近５０％。正常生长条件下的组织净放Ｈ２量较低．而外源２％葡萄糖液可使组织净放Ｈ２量提高近２倍。外加５ｍｍｏｌ／Ｌ的ＮＨ１Ｃｌ溶液可使其固氮活力下降约７０％。故认为Ｇｕｎｎｅｒａ／Ｎｏｓｔｏｃ共生体固氮活力受碳水化合物供应状况及比代谢两者构成的“还原力库”或“电子库”的调节，在此“还原力库”中，Ｈ２代谢起到了一个“中间调节者”的作用。