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Seiichi Shinomiya, Arihiro Iwasaki, Osamu Ohno, Kiyotake Suenaga
In 2014, the γ-pyrone-containing polyketide, yoshinone A, was isolated from the marine cyanobacterium Leptolyngbya sp. and its structure was determined. Yoshinone A inhibited differentiation of 3T3-L1 cells into adipocytes, with an EC50 value of 420 nM without any cytotoxicity, and therefore is expected to be a lead compound for obesity drugs. To establish its absolute configuration, and to provide sufficient amounts for further research, the total synthesis of yoshinone A was achieved through synthesis of its two possible diastereomers...
October 17, 2016: Phytochemistry
Yunpeng Wang, Lei Chen, Weiwen Zhang
BACKGROUND: 3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. In our previous study, the biosynthetic pathway of 3-HP was constructed and optimized in cyanobacterium Synechocystis sp. PCC 6803, which led to 3-HP production directly from CO2 at a level of 837.18 mg L(-1) (348.8 mg/g dry cell weight). As the production and accumulation of 3-HP in cells affect cellular metabolism, a better understanding of cellular responses to 3-HP synthesized internally in Synechocystis will be important for further increasing 3-HP productivity in cyanobacterial chassis...
2016: Biotechnology for Biofuels
Shoubing Wang, Ziran Xu
Increased eutrophication in the recent years has resulted in considerable research focus on identification of methods for preventing cyanobacterial blooms that are rapid and efficient. The objectives of this study were to investigate the effects of dihydroartemisinin and artemether on the growth of Microcystis aeruginosa and to elucidate its mode of action. Variations in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular alkaline phosphatase activity (APA), and chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, ETR, rapid light curves, fast chlorophyll fluorescence curves on fluorescence intensity, and relative variable fluorescence) were evaluated by lab-cultured experiments...
2016: PloS One
M A Sinetova, D A Los
Systemic analysis of stress transcriptomes of the cyanobacterium Synechocystis revealed that all stress-induced genes can be separated into two groups: one is clustered around heat-shock- and another - around cold-shock inducible genes. Genes for so-called heat shock proteins (HSPs) are induced by various stressors, e.g. heat, salt, hyperosmotic environment, reactive oxygen species (ROS), changes in light intensity and quality, or in the redox potential of the photosynthetic electron transport chain components...
October 18, 2016: Molecular BioSystems
Wei Xiong, Gaozhong Shen, Donald A Bryant
The genome of the model cyanobacterium, Synechococcus sp. PCC 7002, encodes two paralogs of CruA-type lycopene cyclases, SynPCC7002_A2153 and SynPCC7002_A0043, which are denoted cruA and cruP, respectively. Unlike the wild-type strain, a cruA deletion mutant is light-sensitive, grows slowly, and accumulates lycopene, γ-carotene, and 1-OH-lycopene; however, this strain still produces β-carotene and other carotenoids derived from it. Expression of cruA from Synechocystis sp. PCC 6803 (cruA 6803) in Escherichia coli strains that synthesize either lycopene or γ-carotene did not lead to the synthesis of either γ-carotene or β-carotene, respectively...
October 14, 2016: Photosynthesis Research
Bradley W Abramson, Benjamin Kachel, David M Kramer, Daniel C Ducat
In plants, a limited capacity to utilize or export the end products of the Calvin Benson cycle (CB) from photosynthetically-active source cells to non-photosynthetic sink cells can result in reduced carbon capture, photosynthetic electron transport (PET) and lowered photochemical efficiency. The downregulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed "sink limitation". Recently, several cyanobacterial and algal strains engineered to over-produce target metabolites have exhibited increased photochemistry suggesting possible source-sink regulatory mechanisms may be involved...
October 13, 2016: Plant & Cell Physiology
Natalie C Sadler, Hans C Bernstein, Matthew R Melnicki, Moiz A Charania, Eric A Hill, Lindsey N Anderson, Matthew E Monroe, Richard D Smith, Alexander S Beliaev, Aaron T Wright
: Photobiologically synthesized hydrogen (H2) gas is carbon-neutral to produce and clean to combust, making it an ideal biofuel. Cyanothece sp. ATCC 51142 is a cyanobacterium capable of performing simultaneous oxygenic photosynthesis and H2 production, a highly perplexing phenomenon because H2 evolving enzymes are O2-sensitive. We employed a systems-level in vivo chemoproteomic profiling approach to explore the cellular dynamics of protein thiol redox, and how thiol redox mediates the function of the dinitrogenase NifHDK, an enzyme complex capable of aerobic hydrogenase activity...
October 14, 2016: Applied and Environmental Microbiology
Yu Nakashima, Yoko Egami, Miki Kimura, Toshiyuki Wakimoto, Ikuro Abe
Sponge metagenomes are a useful platform to mine cryptic biosynthetic gene clusters responsible for production of natural products involved in the sponge-microbe association. Since numerous sponge-derived bioactive metabolites are biosynthesized by the symbiotic bacteria, this strategy may concurrently reveal sponge-symbiont produced compounds. Accordingly, a metagenomic analysis of the Japanese marine sponge Discodermia calyx has resulted in the identification of a hybrid type I polyketide synthase-nonribosomal peptide synthetase gene (kas)...
2016: PloS One
Kazuyoshi Murata, Sayuri Hagiwara, Yoshitaka Kimori, Yasuko Kaneko
Some cyanobacteria exhibit compaction of DNA in synchrony with their circadian rhythms accompanying cell division. Since the structure is transient, it has not yet been described in detail. Here, we successfully visualize the ultrastructure of compacted DNA in the cyanobacterium Synechococcus elongatus PCC 7942 under rigorous synchronized cultivation by means of high-voltage cryo-electron tomography. In 3D reconstructions of rapidly frozen cells, the compacted DNA appears as an undulating rod resembling a eukaryotic condensed chromosome...
October 12, 2016: Scientific Reports
Masato Kaneda, Kosuke Sueyoshi, Toshiaki Teruya, Hiroaki Ohno, Nobutaka Fujii, Shinya Oishi
Odoamide is a novel cyclic depsipeptide with highly potent cytotoxic activity isolated from the Okinawan marine cyanobacterium Okeania sp. It contains a 26-membered macrocycle composed of a fatty acid moiety, a peptide segment and isoleucic acid. Four possible stereoisomers of the odoamide polyketide substructure were synthesised using a chiral pool approach. The first total synthesis of odoamide was also successfully achieved. The structure of synthetic odoamide was verified by comparing its NMR spectra with those of the natural product...
September 26, 2016: Organic & Biomolecular Chemistry
Alexander Klotz, Jens Georg, Lenka Bučinská, Satoru Watanabe, Viktoria Reimann, Witold Januszewski, Roman Sobotka, Dieter Jendrossek, Wolfgang R Hess, Karl Forchhammer
The molecular and physiological mechanisms involved in the transition of microbial cells from a resting state to the active vegetative state are critically relevant for solving problems in fields ranging from microbial ecology to infection microbiology. Cyanobacteria that cannot fix nitrogen are able to survive prolonged periods of nitrogen starvation as chlorotic cells in a dormant state. When provided with a usable nitrogen source, these cells re-green within 48 hr and return to vegetative growth. Here we investigated the resuscitation of chlorotic Synechocystis sp...
October 5, 2016: Current Biology: CB
Vipaporn Cheewinthamrongrod, Hakuto Kageyama, Tanapat Palaga, Teruhiro Takabe, Rungaroon Waditee-Sirisattha
Mycosporine-like amino acids (MAAs) are a group of natural sunscreen compounds that possess highly photoprotective properties. The most commonly found MAAs in marine organisms is shinorine, porphyra-334, and mycosporine-glycine. However, the halophilic species accumulate mycosporine-2-glycine (M2G) as the major MAA. In this study, we have investigated the protective effect of M2G against oxidative stress. In vitro radical scavenging activity revealed that M2G exhibited a significant inhibition with scavenging concentration (SC) 50 value of 22±1...
September 29, 2016: Journal of Photochemistry and Photobiology. B, Biology
Xiaoxing Huang, Wei Huang, Li Li, Xihuan Sun, Siyang Song, Qingyan Xu, Lianru Zhang, Bang-Guo Wei, Xianming Deng
Marine natural products are served as attractive source of anticancer therapeutics, with the great success of "first-in-class" drugs, such as Yondelis, Halaven, and Brentuximab vendotin. Lagunamides A-C from marine cyanobacterium, Lyngbya majuscula, exhibit exquisite growth inhibitory activities against cancer cells. In this study, we have systematically investigated the structure-activity relationships (SAR) of a concise collection of lagunamide A and its analogs constructed by total chemical synthesis against a broad panel of cancer cells derived from various tissues or organs, including A549, HeLa, U2OS, HepG2, BEL-7404, BGC-823, HCT116, MCR-7, HL-60, and A375...
October 7, 2016: Molecular Pharmaceutics
Jun Hou, Yangyang Yang, Peifang Wang, Chao Wang, Lingzhan Miao, Xun Wang, Bowen Lv, Guoxiang You, Zhilin Liu
Extracellular polymeric substances (EPS) are key components of the cyanobacterium Microcystis aeruginosa and play an important role in cyanobacteria blooms formation. Here, we analyzed the effects of 48-h exposure to nanosized CeO2 (n-CeO2), CuO (n-CuO), and ZnO (n-ZnO) on the production and composition of EPS of M. aeruginosa. Toxicity experiments revealed that soluble nanoparticles (NPs) (n-ZnO, n-CuO) demonstrated higher toxicity to cells and caused membrane damage. The production of LB-EPS increased by 34...
October 5, 2016: Environmental Science and Pollution Research International
Sebastian Szewczyk, Wojciech Giera, Sandrine D'Haene, Rienk van Grondelle, Krzysztof Gibasiewicz
Excitation energy transfer in monomeric and trimeric forms of photosystem I (PSI) from the cyanobacterium Synechocystis sp. PCC 6803 in solution or immobilized on FTO conducting glass was compared using time-resolved fluorescence. Deposition of PSI on glass preserves bi-exponential excitation decay of ~4-7 and ~21-25 ps lifetimes characteristic of PSI in solution. The faster phase was assigned in part to photochemical quenching (charge separation) of excited bulk chlorophylls and in part to energy transfer from bulk to low-energy (red) chlorophylls...
October 1, 2016: Photosynthesis Research
Bertram M Berla, Himadri B Pakrasi
No abstract text is available yet for this article.
October 15, 2016: Applied and Environmental Microbiology
Daniel C O Thornton, Jie Chen
Exopolymer particles are found throughout the ocean and play a significant biogeochemical role in carbon cycling. Transparent exopolymer particles (TEP) are composed of acid polysaccharides and Coomassie staining particles (CSP) are proteins. TEP have been extensively studied in the ocean, while CSP have been largely overlooked. The objective of this research was to determine the role of stress and cell permeability in the formation of TEP and CSP. The diatom Thalassiosira weissflogii and cyanobacterium Synechococcus elongatus were grown in batch cultures and exposed to hydrogen peroxide (0, 10, and 100 μM) as an environmental stressor...
September 30, 2016: Journal of Phycology
Tiago B Afonso, M Sofia Costa, Roberta Rezende de Castro, Sara Freitas, Artur Silva, Maria Paula Cruz Schneider, Rosário Martins, Pedro N Leão
The glycosylated and halogenated dialkylresorcinol (DAR) compounds bartolosides A-D (1-4) were recently discovered from marine cyanobacteria and represent a novel family of glycolipids, encoded by the brt biosynthetic gene cluster. Here, we report the isolation and NMR- and MS-based structure elucidation of monoglycosylated bartolosides E-K (5-11), obtained from Synechocystis salina LEGE 06099, a strain closely related to the cyanobacterium that produces the diglycosylated 2-4. In addition, a genome region containing orthologues of brt genes was identified in this cyanobacterium...
September 28, 2016: Journal of Natural Products
Prachi Zawar, Vivek Javalkote, Robert Burnap, Pramod Mahulikar, Pravin Puranik
The present study reports a process wherein CO2 is captured in the form of bicarbonates using calcium oxide and photosynthetically fixed into biomass. Microalgal cultures viz. Chlorella sorokiniana PAZ and Arthrospira sp. VSJ were grown in the medium containing bicarbonates. The rate of bicarbonate utilization by C. sorokiniana PAZ was higher when CO2 trapped in the presence of 2.67mM calcium oxide than in the presence of 10mM sodium hydroxide and with direct addition of 10mM sodium bicarbonate. For Arthrospira sp...
December 2016: Bioresource Technology
M A Sinetova, D A Los
A systemic transcriptome analysis of the cyanobacterium Synechocystis sp. PCC 6803 revealed a number of genes whose transcription is induced in response to almost all abiotic stresses (heat shock, salt stress, osmotic stress, oxidative stress, changes in light intensity or spectral composition, and changes in the redox potential of electron transport chain (ETC) components). Heat shock protein (HSP) genes were induced by all types of stress, forming a group of genes that universally react to various changes in the environment...
July 2016: Molekuliarnaia Biologiia
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