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Anu Humisto, Jouni Jokela, Liwei Liu, Matti Wahlsten, Hao Wang, Perttu Permi, João Paulo Machado, Agostinho Antunes, David P Fewer, Kaarina Sivonen
Swinholides are 42-carbon ring polyketides with a twofold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge Theonella sp. and were long-suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of the symbiotic heterotrophic proteobacterium. Here we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp...
November 17, 2017: Applied and Environmental Microbiology
Geeta G Shirnalli, Manish S Kaushik, Ajay Kumar, Gerard Abraham, Pawan K Singh
Cyanobacteria are known to exhibit their efficiency in producing high concentrations of compounds of commercial value. Arthrospira is one such cyanobacterium which is considered as important source of protein (65%) and other nutrients. In present study, chemical mutagenesis using N-methyl-Ń-Nitro-nitrosoguanidine (NTG), a proven potent mutagen for cyanobacteria was used to bring stable and desirable alteration in Arthrospira platensis ARM 730. Three morphological mutants (G-1, G-2, and SF) were selected and characterized...
November 17, 2017: Journal of Basic Microbiology
Shigeki Ehira, Takuto Takeuchi, Akiyoshi Higo
Cyanobacteria, which perform oxygenic photosynthesis, have drawn attention as hosts for the direct production of biofuels and commodity chemicals from CO2 and H2O using light energy. Although cyanobacteria capable of producing diverse chemicals have been generated by metabolic engineering, anaerobic non-photosynthetic culture conditions are often necessary for their production. In this study, we conducted cell type-specific metabolic engineering of the filamentous cyanobacterium Anabaena sp. PCC 7120, which forms a terminally differentiated cell called a heterocyst with a semi-regular spacing of 10-15 cells...
November 15, 2017: Applied Microbiology and Biotechnology
Alonso M Acuña, Pascal van Alphen, Filipe Branco Dos Santos, Rienk van Grondelle, Klaas J Hellingwerf, Ivo H M van Stokkum
Cyanobacterial thylakoid membranes are known to host photosynthetic and respiratory complexes. This hampers a straight forward interpretation of the highly dynamic fluorescence originating from photosynthetic units. The present study focuses on dark-to-light transitions in whole cells of a PSI-deficient mutant of the cyanobacterium Synechocystis sp. PCC 6803. The time-dependent cellular fluorescence spectrum has been measured, while having previously exposed the cells to different conditions that affect respiratory activity...
November 11, 2017: Biochimica et Biophysica Acta
Vaishali Dutt, Shireesh Srivastava
Many freshwater cyanobacteria accumulate polyhydroxybutyrate (PHB) under nitrogen or phosphorus deprivation. While prior literature has shed lights on transcriptomic and metabolomic changes in the model cyanobacterium Synechocystis PCC 6803 cells, the quantitative contributions of the newly fixed carbon following nitrogen deprivation or the externally added acetate to PHB synthesis are not clear. Similarly, it is not clear how photomixotrophy affects precursor contributions. In this study, we show that (i) the pre-growth mode (photoautotrophic or photomixotrophic), while significantly impacting glycogen levels, does not have any significant effect on PHB levels, (ii) the carbon fixed following nitrogen deprivation contributes 26% of C for PHB synthesis in photoautotrophically pre-grown cells and its contribution to the PHB synthesis goes down with the addition of acetate at the resuspension phase or with photomixotrophic pre-growth, (iii) the acetate added at the start of nitrogen deprivation, doubles the intracellular PHB levels and contributes 44-48% to PHB synthesis and this value is not greatly affected by how the cells were pre-grown...
November 9, 2017: Photosynthesis Research
Fangfang Cai, Gongliang Yu, Kai Zhang, Youxin Chen, Qiang Li, Yiming Yang, Jinlin Xie, Yilang Wang, Renhui Li
Taste and odor (T & O) episodes always cause strong effects on drinking water supply system. Luanhe River diversion into Tianjin City in China is an important drinking water resource. Massive growth of a benthic filamentous cyanobacterium with geosmin production in the open canal caused a strong earthy odor episode in Tianjin. On the basis of the morphological and molecular identification of this cyanobacterium as Oscillatoria limosa Agardh ex Gomont, the genetic basis for geosmin biosynthesis and factors influencing growth and geosmin production of O...
November 2017: Harmful Algae
Shoki Ito, Masahiro Takeya, Takashi Osanai
Lactate/lactic acid is an important chemical compound for the manufacturing of bioplastics. The unicellular cyanobacterium Synechocystis sp. PCC 6803 can produce lactate from carbon dioxide and possesses D-lactate dehydrogenase (Ddh). Here, we performed a biochemical analysis of the Ddh from this cyanobacterium (SyDdh) using recombinant proteins. SyDdh was classified into a cyanobacterial clade similar to those from Gram-negative bacteria, although it was distinct from them. SyDdh can use both pyruvate and oxaloacetate as a substrate and is activated by fructose-1,6-bisphosphate and repressed by divalent cations...
November 8, 2017: Scientific Reports
Akiyoshi Higo, Atsuko Isu, Yuki Fukaya, Shigeki Ehira, Toru Hisabori
Anabaena sp. PCC 7120 (A. 7120) is a heterocyst-forming multicellular cyanobacterium that performs nitrogen fixation. This cyanobacterium has been extensively studied as a model for multicellularity in prokaryotic cells. We have been interested in photosynthetic production of nitrogenous compounds using A. 7120. However, the lack of efficient gene repression tools has limited its usefulness. We originally developed an artificial endogenous gene repression method in this cyanobacterium using small antisense RNA (Higo A...
November 3, 2017: Plant & Cell Physiology
Travis C Korosh, Andrew L Markley, Ryan L Clark, Laura L McGinley, Katherine D McMahon, Brian F Pfleger
L-lysine and other amino acids are commonly produced through fermentation using strains of heterotrophic bacteria such as Corynebacterium glutamicum. Given the large amount of sugar this process consumes, direct photosynthetic production is intriguing alternative. In this study, we report the development of a cyanobacterium, Synechococcus sp. strain PCC 7002, capable of producing L-lysine with CO2 as the sole carbon-source. We found that heterologous expression of a lysine transporter was required to excrete lysine and avoid intracellular accumulation that correlated with poor fitness...
October 28, 2017: Metabolic Engineering
Yunlong Zhang, Ran Zhang, Rebecca-Ayme Hughes, Jingqiu Dai, Joshua R Gurr, Philip G Williams, Eric S Miller, Jonathan S Lindsey
INTRODUCTION: Tolyporphins are unusual tetrapyrrole macrocycles produced by a non-axenic filamentous cyanobacterium (HT-58-2). Tolyporphins A-J, L, and M share a common dioxobacteriochlorin core, differ in peripheral substituents, and exhibit absorption spectra that overlap that of the dominant cyanobacterial pigment, chlorophyll a. Identification and accurate quantitation of the various tolyporphins in these chlorophyll-rich samples presents challenges. OBJECTIVE: To develop methods for the quantitative determination of tolyporphins produced under various growth conditions relative to that of chlorophyll a...
November 6, 2017: Phytochemical Analysis: PCA
Minglei Ren, Guiying Zhang, Zi Ye, Zhixian Qiao, Meili Xie, Yan Lin, Tao Li, Jindong Zhao
Disentangling the interactions between cyanobacteria and associated bacterial community is important for understanding the mechanisms that mediate the formation of cyanobacterial blooms in freshwater ecosystems. Despite the fact that a metagenomic approach enables researchers to profile the structure of microbial communities associated with cyanobacteria, reconstructing genome sequences for all members remains inefficient, due to the inherent enormous microbial diversity. Here, we have established a stable coculture system under high salinity, originally from a mixture of an axenic cyanobacterium Synechococcus sp...
November 2, 2017: AMB Express
Ekaterina Kuchmina, Stephan Klähn, Annik Jakob, Werner Bigott, Heike Enke, Ulf Dühring, Annegret Wilde
Ethylene is a gaseous signal sensed by plants and bacteria. Heterologous expression of the ethylene-forming enzyme (EFE) from Pseudomonas syringae in cyanobacteria leads to the production of ethylene under photoautotrophic conditions. The recent characterization of an ethylene-responsive signalling pathway affecting phototaxis in the cyanobacterium Synechocystis sp. PCC 6803 implied that biotechnologically relevant ethylene synthesis may induce regulatory processes that are not related to changes in metabolism...
November 1, 2017: Microbiology
Charlotte L Kvasnovsky, Lex E X Leong, Jocelyn M Choo, Guy C J Abell, Savvas Papagrigoriadis, Kenneth D Bruce, Geraint B Rogers
BACKGROUND: There is growing consensus that symptomatic uncomplicated diverticular disease is a chronic inflammatory condition, and that alterations in the fecal microbiota may contribute to its pathogenesis. OBJECTIVE: The aim of this study was to relate the fecal microbiota composition in symptomatic uncomplicated diverticular disease to measures of inflammation, symptoms, and history of previous acute diverticulitis. PARTICIPANTS AND METHODS: Fecal microbiota composition in 28 individuals with symptomatic uncomplicated diverticular disease was characterized by 16S RNA gene amplicon sequencing...
October 27, 2017: European Journal of Gastroenterology & Hepatology
Paramasivan Manivannan, Gangatharan Muralitharan, Nainangu Prasanna Balaji
Marine Lyngbya has been proven as a potent anticancer agent by disrupting microfilament network. Lyngbya and its associated cyanobacterial compounds have been stressed for futuristic advancements in cancer research and have foreseen explicit advancements in the recent era. Moreover, compounds like lyngbyabellins, lyngbyastatins and other derived toxins are significantly studied. Therefore it is of interest to study the efficacies of Lyngbya fatty acid derivatives. Cytotoxicity and DNA laddering studies proves the efficiency and safety of marine Lyngbya...
2017: Bioinformation
Takako Masuda, Gábor Bernát, Martina Bečková, Eva Kotabová, Evelyn Lawrenz, Martin Lukeš, Josef Komenda, Ondřej Prášil
The oceanic unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501 exhibits large diel changes in abundance of both Photosystem II (PSII) and Photosystem I (PSI). To understand the mechanisms underlying these dynamics, we assessed photosynthetic parameters, photosystem abundance and composition, and chlorophyll-protein biosynthesis over a diel cycle. Our data show that the decline in PSII activity and abundance observed during the dark period was related to a light-induced modification of PSII, which, in combination with the suppressed synthesis of membrane proteins, resulted in monomerization and gradual disassembly of a large portion of PSII core complexes...
October 27, 2017: Environmental Microbiology
Jin-Long Shang, Zhong-Chun Zhang, Xiao-Yue Yin, Min Chen, Fu-Hua Hao, Kai Wang, Jun-Li Feng, Hai-Feng Xu, Yan-Chao Yin, Hui-Ru Tang, Bao-Sheng Qiu
The small-molecule sunscreen compounds, mycosporine-like amino acids (MAAs), have strong UV absorption and can protect cyanobacteria against UV-B damage. However, the molecular mechanism underlying UV-B signaling and MAA chemical diversity remain largely unclear. Here, we identified a five-gene cluster for MAA biosynthesis in the solar radiation and desiccation tolerant cyanobacterium Nostoc flagelliforme. A LuxR family protein OrrA was identified as a positive UV-B responsive regulator binding to the promoter region of this gene cluster...
October 27, 2017: Environmental Microbiology
Lishuang Wu, Xingliang Guo, Xianglong Liu, Hong Yang
Harmful cyanobacterial blooms have severely impaired freshwater quality and threatened human health worldwide. Here, a Gram-positive bacterium, Bacillus sp. strain S51107, which exhibits strong algicidal activity against Microcystis aeruginosa, was isolated from Lake Taihu. We found that the algicidal activity of strain S51107 was regulated primarily by NprR-NprX quorum sensing (QS), in which the mature form of the signaling peptide NprX was identified as the SKPDIVG heptapeptide. Disruption of the nprR-nprX cassette markedly decreased the algicidal activity, and complemented strains showed significantly recovered algicidal activity...
2017: Frontiers in Microbiology
Jeffrey R Johansen, Jan Mareš, Nicole Pietrasiak, Markéta Bohunická, Jan Zima, Lenka Štenclová, Tomáš Hauer
A highly divergent 16S rRNA gene was found in one of the five ribosomal operons present in a species complex currently circumscribed as Scytonema hyalinum (Nostocales, Cyanobacteria) using clone libraries. If 16S rRNA sequence macroheterogeneity among ribosomal operons due to insertions, deletions or truncation is excluded, the sequence heterogeneity observed in S. hyalinum was the highest observed in any prokaryotic species thus far (7.3-9.0%). The secondary structure of the 16S rRNA molecules encoded by the two divergent operons was nearly identical, indicating possible functionality...
2017: PloS One
Matthew D Blain-Hartung, Nathan Clarke Rockwell, J Clark Lagarias
Phytochromes and cyanobacteriochromes (CBCRs) use double bond photoisomerization of their linear tetrapyrrole (bilin) chromophores within cGMP-specific phosphodiesterases/Adenylyl cyclases/FhlA (GAF) domain-containing photosensory modules to regulate signaling activity of C-terminal output domains. CBCRs exhibit much more diverse photocycles than phytochromes, and they are often found in large modular proteins such as Tlr0924 (SesA), one of three blue light regulators of cell aggregation in the cyanobacterium Thermosynechococcus elongatus...
October 26, 2017: Biochemistry
Erika Berenice Martínez-Ruiz, Fernando Martínez-Jerónimo
The extensive use of 2,4-dichlorophenoxiacetic acid (2,4-D) in agriculture is an important source of pollution to water and soil. Toxicity of commonly used herbicides to non-target, planktonic photosynthetic organisms has not been described completely yet. Therefore, we determined the effect of subinhibitory 2,4-D concentrations on the Chlorophycean alga Ankistrodesmus falcatus and on a toxigenic strain of the cyanobacterium Microcystis aeruginosa. Population growth, photosynthetic pigments, macromolecular biomarkers (carbohydrates, lipids, and protein), and antioxidant enzymes (catalase [CAT], glutathione peroxidase [GPx], and superoxide dismutase [SOD]) were quantified, and the integrated biomarker response (IBR) was calculated...
October 22, 2017: Science of the Total Environment
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