Expression of organophosphorus-degradation gene （opd） in aggregating and non-aggregating filamentous nitrogen-fixing cyanobacteria
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在细丝状的修理 N2 cyanobacteria 的遗传工程通常包含淡水藻类的一种 sp。PCC 7120 和几另外的非聚集的种。如此的种类的集体文化和收获是相对聚集种类消费的更多的精力。为聚集种类建立一个基因转移系统，我们测试了许多种类淡水藻类的一种和 Nostoc，和识别 Nostoc muscorum FACHB244 遗传上作为能是的种操作了使用 conjugative 基因转移系统。在水的环境支持 organophosphorus 污染物质的 biodegradation，我们介绍了包含 organophosphorus 降级基因(opd ) 进淡水藻类的一种 sp 的 plasmid。由变化形式的 PCC 7120 和 Nostoc muscorum FACHB244。opd 基因被一个强壮的倡导者，驾驶 P psbA。从种类，我们获得了举办 organophosphorus 降级活动的转基因的紧张。在 25 掳 C，转基因的淡水藻类的一种和 Nostoc 紧张的整个房间的活动是 0.163 卤 0 .001 和 0.289 卤 0 .042 unit/渭 g Chl 一分别地。然而，源于基因转移的大多数殖民地没显示出活动。定序的 PCR 和 DNA 在一些殖民地在 plasmid 揭示了删除或重新整理。绿色的表示荧光灯从在淡水藻类的一种 sp 的一样的倡导者的蛋白质基因。PCC 7120 显示出类似的结果。这些结果建议有潜力与转基因的 cyanobacteria 支持 organophosphorus 污染物质的降级，高表示的转基因的殖民地的那种选择为淡水藻类的一种和 Nostoc 种类的遗传工程是重要的。第一次，我们在聚集建立了基因转移和表示系统细丝状的修理 N2 cyanobacterium。Nostoc muscorum FACHB244 的基因操作系统能在污染物质和珍贵蛋白质或代谢物的大规模生产的消除被利用。Keywords:
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Research on production of polyhydroxyalkanoates (PHA) by microorganisms has captured attention over the last two decades, since PHA have similar properties as petroleum-based thermoplastics, yet are close to carbon neutral and made from renewable sources. Cyanobacteria are considered to be good PHA producers because of their simple nutrient requirements (mainly water, sunlight and CO2) and fast cell growth. However, knowledge of metabolisms behind PHA production by cyanobacteria is limited. Therefore, gene expression analysis of cyanobacteria is required to get a thorough understanding at the molecular level, and gene expression analysis requires the extraction of high quality RNA. Extracting high quality intact RNA from cyanobacteria is problematic due to their complicated cell wall structure and excessive polysaccharides produced by cells. Previous work on RNA extraction from cyanobacteria is either strain-specific or involves handling of hazardous chemicals like toxic chaotropic agents, saturated hot phenol or liquid nitrogen. With this work, we developed a low-cost RNA extraction method using a simple CTAB extraction buffer. Three morphologically distinct cyanobacteria strains, Synechocystis sp. PCC 6803, Plectonema sp. strain UTEX 1541, and Nostoc muscorum UTEX 1037 were used to testify the validity of this new method. Two traditional extraction protocols, using the Qiagen RNeasy Mini kit and TRIzol Reagent respectively for cyanobacteria were also optimized and analyzed with the same species. The newly developed CTAB method successfully extracted total RNA of high quality and quantity from the three selected strains, and the extracted total RNA were of sufficient quantity and quality for RT-PCR after DNase I treatment. Compared to the two traditional extraction methods, both the purity and the yield of extracted total RNA were greatly improved when using CTAB method: yields was improved up to 13 times higher, and both the A260/A280 and A260/A230 ratio indicated less contaminations in extracted RNA. Furthermore, the experimental cost of CTAB method was significantly lowered by up to 83%, yet still easy to perform.
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ABSTRACT The production of hepatotoxic cyclic heptapeptides, microcystins, is almost exclusively reported from planktonic cyanobacteria. Here we show that a terrestrial cyanobacterium Nostoc sp. strain IO-102-I isolated from a lichen association produces six different microcystins. Microcystins were identified with liquid chromatography-UV mass spectrometry by their retention times, UV spectra, mass fragmentation, and comparison to microcystins from the aquatic Nostoc sp. strain 152. The dominant microcystin produced by Nostoc sp. strain IO-102-I was the highly toxic [ADMAdda 5 ]microcystin-LR, which accounted for ca. 80% of the total microcystins. We assigned a structure of [DMAdda 5 ]microcystin-LR and [ d -Asp 3 ,ADMAdda 5 ]microcystin-LR and a partial structure of three new [ADMAdda 5 ]-XR type of microcystin variants. Interestingly, Nostoc spp. strains IO-102-I and 152 synthesized only the rare ADMAdda and DMAdda subfamilies of microcystin variants. Phylogenetic analyses demonstrated congruence between genes involved directly in microcystin biosynthesis and the 16S rRNA and rpoC1 genes of Nostoc sp. strain IO-102-I. Nostoc sp. strain 152 and the Nostoc sp. strain IO-102-I are distantly related, revealing a sporadic distribution of toxin production in the genus Nostoc. Nostoc sp. strain IO-102-I is closely related to Nostoc punctiforme PCC 73102 and other symbiotic Nostoc strains and most likely belongs to this species. Together, this suggests that other terrestrial and aquatic strains of the genus Nostoc may have retained the genes necessary for microcystin biosynthesis.
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Abstract Purpose : Cyanobacteria are ecologically relevant prokaryotes that can be found in environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been extensively considered in cyanobacteria. So far, most studies have focused on treatment of wastewaters using microalgae leads to remarkable reduction of an array of organic and inorganic nutrients, but what takes place in the extracellular environment when cells are exposed to external supplementation with heavy metals remains largely unknown. Methods : Here, extracellular polymeric substances (EPS) production in strains Nostoc sp. N27P72 and Nostoc sp. FB71 isolated from different habitats are reported and compared. Cultures of both strains, supplemented with either glucose, sucrose, lactose or maltose showed that production of EPS and cell dry weight was boosted by maltose supplementation. Result : Nostoc sp. N27P72 which was isolated from lime stones was higher, resulting in 9.1 ± 0.05 µg/ml and 1.01 ± 0.06 g/l in EPS and cell dry. The cell cultures tested for their ability to remove Cu(II), Cr(III) and Ni(II) in media culture containing the maltose and without maltose as control culture. Remarkably, we showed that although these elements can be toxic, supplementing the media culture can effectively sequester their toxic effects by increasing the production of EPSs, carbohydrates and total soluble proteins in comparison to control. The crude EPS showed metal adsorption capacity assuming the order Ni(II)> Cu(II)> Cr(III) from metal-binding experiments. Nickel was preferentially biosorbed with a maximal uptake of 188.8 ± 0.14 mg (g cell dry wt) -1 crude EPS. FT-IR spectroscopy revealed treatment with Ni made changes in the functional groups and glycoside linkages in both strains. Results of Gas Chromatography Mass Spectrometry (GC–MS) to determine the biochemical composition of Nostoc sp. N27P72 showed that strong Ni(II) removal capability is suspected to be associated with the high Cyclotrisiloxane and 1,2-Benzenedicarboxylic acid content. Conclusion : The results of these investigates specified that strains Nostoc sp. N27P72 is good candidates for the commercial production of EPS and might be utilized in bioremediation field as an alternative to synthetic and abiotic flocculants.
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Photobioreactor
Biosorption
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Metal Toxicity
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因为他们的第二等的代谢物， Cyanobacteria 最近与有势力吸引了许多注意生物活动和不平常的结构。这份报纸在隔离上考察一些最近的研究，结构，说明和 bioactive 的生物活动从 cyanobacteriaNostoc 加重种类。
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Extracellular polysaccharide
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Isolation of cyanobacteria dominated in the soil samples collected from different sites in Kafr El-Sheikh, and El-Dkahlia governorates isolates were successfully obtained as bacterial free cyanobacteria.They were identified cyanobacteria was carried out using the following: thallus color, thallus morphology and size of heterocyst, vegetative and reproductive cells.Heterocyst-forming cyanobacteria were also cultured as Anabaena sp., Nostoc sp., Oscillatoria sp., and Chroococcus sp.Nostoc sp .were isolated at high frequency; Nostoc sp. and Anabaena sp.isolates representing in kafr El-Sheikh and El-Dakahlia Governorates.Less frequency of cyanobacteria belonging to different genera namely Oscillatoria sp. and Chroococcus sp.Nostoc spp.were recorded highest amount of fixed nitrogen and mass production with in increasing incubation period of interacellular and /or extracellular nitrogenfixation.While,the most active strains for nitrogenase activity were Nostoc mucorum K and Anabaena oryzae D.
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Thallus
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