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https://www.readbyqxmd.com/read/28918447/an-improved-crystal-structure-of-c-phycoerythrin-from-the-marine-cyanobacterium-phormidium-sp-a09dm
#1
Ravi R Sonani, Aleksander W Roszak, Claire Ortmann de Percin Northumberland, Datta Madamwar, Richard J Cogdell
C-Phycoerythrin (PE) from Phormidium sp. A09DM has been crystallized using different conditions and its structure determined to atomic resolution (1.14 Å). In order for the pigment present, phycoerythrobilin (PEB), to function as an efficient light-harvesting molecule it must be held rigidly (Kupka and Scheer in Biochim Biophys Acta 1777:94-103, 2008) and, moreover, the different PEB molecules in PE must be arranged, relative to each other, so as to promote efficient energy transfer between them. This improved structure has allowed us to define in great detail the structure of the PEBs and their binding sites...
September 16, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28916813/genome-sequencing-reveals-metabolic-and-cellular-interdependence-in-an-amoeba-kinetoplastid-symbiosis
#2
Goro Tanifuji, Ugo Cenci, Daniel Moog, Samuel Dean, Takuro Nakayama, Vojtěch David, Ivan Fiala, Bruce A Curtis, Shannon J Sibbald, Naoko T Onodera, Morgan Colp, Pavel Flegontov, Jessica Johnson-MacKinnon, Michael McPhee, Yuji Inagaki, Tetsuo Hashimoto, Steven Kelly, Keith Gull, Julius Lukeš, John M Archibald
Endosymbiotic relationships between eukaryotic and prokaryotic cells are common in nature. Endosymbioses between two eukaryotes are also known; cyanobacterium-derived plastids have spread horizontally when one eukaryote assimilated another. A unique instance of a non-photosynthetic, eukaryotic endosymbiont involves members of the genus Paramoeba, amoebozoans that infect marine animals such as farmed fish and sea urchins. Paramoeba species harbor endosymbionts belonging to the Kinetoplastea, a diverse group of flagellate protists including some that cause devastating diseases...
September 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28916705/the-effects-of-the-exopolysaccharide-and-growth-rate-on-the-morphogenesis-of-the-terrestrial-filamentous-cyanobacterium-nostoc-flagelliforme
#3
Lijuan Cui, Haiyan Xu, Zhaoxia Zhu, Xiang Gao
The terrestrial cyanobacterium Nostoc flagelliforme, which contributes to carbon and nitrogen supplies in arid and semi-arid regions, adopts a filamentous colony form. Owing to its herbal and dietary values, this species has been overexploited. Largely due to the lack of understanding on its morphogenesis, artificial cultivation has not been achieved. Additionally, it may serve as a useful model for recognizing the morphological adaptation of colonial cyanobacteria in terrestrial niches. However, it shows very slow growth in native habitats and is easily disintegrated under laboratory conditions...
September 15, 2017: Biology Open
https://www.readbyqxmd.com/read/28912214/response-to-comment-on-the-complex-effects-of-ocean-acidification-on-the-prominent-n2-fixing-cyanobacterium-trichodesmium
#4
Dalin Shi, Rong Shen, Sven A Kranz, François M M Morel, Haizheng Hong
Hutchins et al question the validity of our results showing that under fast growth conditions, the beneficial effect of high CO2 on Trichodesmium is overwhelmed by the deleterious effect of the concomitant decrease in ambient and cellular pH. The positive effect of acidification reported by Hutchins and co-workers is likely caused by culture conditions that support suboptimal growth rates.
September 15, 2017: Science
https://www.readbyqxmd.com/read/28912213/comment-on-the-complex-effects-of-ocean-acidification-on-the-prominent-n2-fixing-cyanobacterium-trichodesmium
#5
David A Hutchins, Feixue Fu, Nathan G Walworth, Michael D Lee, Mak A Saito, Eric A Webb
Hong et al (Reports, 5 May 2017, p. 527) suggested that previous studies of the biogeochemically significant marine cyanobacterium Trichodesmium showing increased growth and nitrogen fixation at projected future high CO2 levels suffered from ammonia or copper toxicity. They reported that these rates instead decrease at high CO2 when contamination is alleviated. We present and discuss results of multiple published studies refuting this toxicity hypothesis.
September 15, 2017: Science
https://www.readbyqxmd.com/read/28911053/co-ordination-of-ndh-and-cup-proteins-in-co2-uptake-in-cyanobacterium-synechocystis-sp-pcc-6803
#6
Xunling Han, Nan Sun, Min Xu, Hualing Mi
High and low affinity CO2-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS'), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO2 uptake. In this work, we found that deletion of cupB significantly lowered the growth of cells, and deletion of both cupA and cupB seriously suppressed the growth below pH 7.0 even under 3% CO2. The rate of photosynthetic oxygen evolution was decreased slightly by deletion of cupA but significantly by deletion of cupB and more severely by deletion of both cupA and cupB, especially in response to changed pH conditions under 3% CO2...
June 1, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28900692/tonb-dependent-utilization-of-dihydroxamate-xenosiderophores-in-synechocystis-sp-pcc-6803
#7
Michael M Babykin, Tobias S A Obando, Vladislav V Zinchenko
In Gram-negative bacteria, transport of ferric siderophores through outer membrane is a complex process that requires specific outer membrane transporters and energy-transducing TonB-ExbB-ExbD system in the cytoplasmic membrane. The genome of the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 encodes all putative components of the siderophore-mediated iron uptake system. So far, there has been no experimental evidence for the existence of such a pathway in this organism. On the contrary, its reductive iron uptake pathway has been studied in detail...
September 12, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28899665/toxin-composition-of-the-2016-microcystis-aeruginosa-bloom-in-the-st-lucie-estuary-florida
#8
Stuart Oehrle, Marliette Rodriguez-Matos, Michael Cartamil, Cristian Zavala, Kathleen S Rein
A bloom of the cyanobacteria, Microcystis aeruginosa occurred in the St. Lucie Estuary during the summer of 2016, stimulated by the release of waters from Lake Okeechobee. This cyanobacterium produces the microcystins, a suite of heptapeptide hepatotoxins. The toxin composition of the bloom was analyzed and was compared to an archived bloom sample from 2005. Microcystin-LR was the most abundant toxin with lesser amounts of microcystin variants. Nodularin, cylindrospermopsin and anatoxin-a were not detected.
September 9, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28898827/purification-and-antioxidant-activity-of-phycocyanin-from-synechococcus-sp-r42dm-isolated-from-industrially-polluted-site
#9
Ravi R Sonani, Stuti Patel, Bela Bhastana, Kinnari Jakharia, Mukesh G Chaubey, Niraj K Singh, Datta Madamwar
The cyanobacterium Synechococcus sp. R42DM, isolated from an industrially polluted site Vatva, Gujarat, India was recognized to produce phycocyanin (PC) as major phycobiliprotein. In present study, the combinatorial approach of chemical and physical methods i.e. Triton-X 100 treatment and ultra-sonication was designed for extraction of PC. From cell extract, the intact and functional-PC was purified up to purity 4.03 by ammonium sulphate fractionation and ion-exchange chromatography. The PC displayed considerable in vitro antioxidant and radical-scavenging activity...
August 31, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28893840/the-monoplastidic-bottleneck-in-algae-and-plant-evolution
#10
REVIEW
Jan de Vries, Sven B Gould
Plastids in plants and algae evolved from the endosymbiotic integration of a cyanobacterium by a heterotrophic eukaryote. New plastids can only emerge through fission; thus, the synchronization of bacterial division with the cell cycle of the eukaryotic host was vital to the origin of phototrophic eukaryotes. Most of the sampled algae house a single plastid per cell and basal-branching relatives of polyplastidic lineages are all monoplastidic, as are some non-vascular plants during certain stages of their life cycle...
September 11, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28889978/massive-protein-import-into-the-early-evolutionary-stage-photosynthetic-organelle-of-the-amoeba-paulinella-chromatophora
#11
Anna Singer, Gereon Poschmann, Cornelia Mühlich, Cecilio Valadez-Cano, Sebastian Hänsch, Vanessa Hüren, Stefan A Rensing, Kai Stühler, Eva C M Nowack
The endosymbiotic acquisition of mitochondria and plastids more than 1 Ga ago profoundly impacted eukaryote evolution. At the heart of understanding organelle evolution is the re-arrangement of the endosymbiont proteome into a host-controlled organellar proteome. However, early stages in this process as well as the timing of events that underlie organelle integration remain poorly understood. The amoeba Paulinella chromatophora contains cyanobacterium-derived photosynthetic organelles, termed "chromatophores," that were acquired more recently (around 100 Ma ago)...
September 6, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28889941/ultrasonic-characteristics-and-cellular-properties-of%C3%A2-anabaena-gas-vesicles
#12
Yaoheng Yang, Zhihai Qiu, Xuandi Hou, Lei Sun
Ultrasound imaging is a common modality in clinical examination and biomedical research, but has not played a significant role in molecular imaging for lack of an appropriate contrast agent. Recently, biogenic gas vesicles (GVs), naturally formed by cyanobacteria and haloarchaea, have exhibited great potential as an ultrasound molecular imaging probe with a much smaller size (∼100 nm) and improved imaging contrast. However, the basic acoustic and biological properties of GVs remain unclear, which hinders future application...
September 7, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28889741/adaptation-of-divinyl-chlorophyll-a-b-containing-cyanobacterium-to-different-light-conditions-three-strains-of-prochlorococcus-marinus
#13
Fumiya Hamada, Akio Murakami, Seiji Akimoto
The light-harvesting mechanisms in three strains of Prochlorococcus marinus, CCMP1986, CCMP1375, and CCMP2773, grown under blue and red light-emitting diodes (LEDs) at two intensity levels were investigated. The blue LED was divinyl chlorophyll b (DV-Chl b) selective, and the red LED was DV-Chl a selective. Under the red LED, the relative amount of DV-Chl b in CCMP1375 and CCMP2773 decreased, and the relative amount of zeaxanthin increased in CCMP1375. Furthermore, when the red-LED-grown cells of CCMP1375 were transplanted under the blue LED, pigment composition was remodified to that under the blue LED...
September 11, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28887420/the-flexibility-rigidity-coordination-of-dense-exopolysaccharide-matrix-in-terrestrial-cyanobacteria-acclimated-to-periodic-desiccation
#14
Wen Liu, Lijuan Cui, Haiyan Xu, Zhaoxia Zhu, Xiang Gao
A dense exopolysaccharide (EPS) matrix is crucial for cyanobacterial survival in terrestrial xeric environments, in which cyanobacteria undergo frequent expansion and shrinkage processes during environmental desiccation-rehydration cycles. However, it is unclear how terrestrial cyanobacteria coordinate the structural dynamics of the EPS matrix upon the expansion and shrinkage to avoid potential mechanical stress while benefiting from the matrix. In the present study, we sought to answer this question by investigating the gene expression, protein dynamics, enzymatic characteristics and biological roles of WSPA, an abundantly secreted protein, in the representative terrestrial cyanobacterium Nostoc flagelliforme The results demonstrated that WSPA is a novel β-galactosidase that facilitates softening of the EPS matrix by breaking the polysaccharide backbone under substantial moisture or facilitates the thickening and re-linkage of the broken matrix upon drying process, and thus these regulations are well correlated with moisture availability or desiccation-rehydration cycles...
September 8, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28885833/the-face-of-a-molecule
#15
William H Gerwick
Recent technological advances in mass spectrometry and NMR spectroscopy have enabled new approaches for the rapid and insightful profiling of natural product mixtures. MALDI-MS with the provision of biosynthetic heavy-isotope-labeled precursors can be a powerful method by which to interrogate a natural product metabolome and to gain insight into its unique constituents; this is illustrated herein by the detection, isolation, and characterization of cryptomaldamide. MS/MS-based Molecular Networks, facilitated by the Global Natural Products Social (GNPS) platform, is rapidly changing the way in which we dereplicate known natural products in mixtures, find new analogues in desired structure classes, and identify fundamentally new chemical entities...
September 8, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28884325/the-occurrence-of-toxic-cyanobacterium-cylindrospermopsis-raciborskii-and-its-toxin-cylindrospermopsin-in-the-huong-river-thua-thien-hue-province-vietnam
#16
Thi Thu Lien Nguyen, Tien Hien Hoang, Trung Kien Nguyen, Thi Thuy Duong
This research reports the presence of species Cylindrospermopsis raciborskii and cylindrospermopsin (CYN) in the Huong River and the relationship between species with environmental factors to find a scientific basis for predicting the risk of pollution of the species and CYN in waters. Strains of C. raciborskii isolated from the river were also identified as potentially toxin-producing through the determination of the presence of toxins in the cultures by ELISA; the presence of the genes involved by PCR confirms the CYN-producing ability of species C...
September 7, 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28876933/namalides-b-and-c-and-spumigins-k-n-from-the-cultured-freshwater-cyanobacterium-sphaerospermopsis-torques-reginae
#17
Miriam Sanz, Roberto Kopke Salinas, Ernani Pinto
Chemical investigations of the terrestrial cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 from northern Brazil afforded namalides B (1) and C (2), the first analogues of this anabaenopeptide-like metabolite to be described. Four other related peptides (3-6), termed spumigins K-N, were also identified. Planar structures and absolute configurations for 1, 2, and 3a-6a were deduced by a combination of 2D NMR, HRMS analysis, and Marfey's methodology. Spumigins K-N (3-6) are the first examples of spumigins containing a 2-hydroxy-4-(4-hydroxyphenyl)butanoic acid (Hhpba) in the N-terminal position...
September 6, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28875267/kingdom-chromista-and-its-eight-phyla-a-new-synthesis-emphasising-periplastid-protein-targeting-cytoskeletal-and-periplastid-evolution-and-ancient-divergences
#18
Thomas Cavalier-Smith
In 1981 I established kingdom Chromista, distinguished from Plantae because of its more complex chloroplast-associated membrane topology and rigid tubular multipartite ciliary hairs. Plantae originated by converting a cyanobacterium to chloroplasts with Toc/Tic translocons; most evolved cell walls early, thereby losing phagotrophy. Chromists originated by enslaving a phagocytosed red alga, surrounding plastids by two extra membranes, placing them within the endomembrane system, necessitating novel protein import machineries...
September 5, 2017: Protoplasma
https://www.readbyqxmd.com/read/28874736/genfire-a-generalized-fourier-iterative-reconstruction-algorithm-for-high-resolution-3d-imaging
#19
Alan Pryor, Yongsoo Yang, Arjun Rana, Marcus Gallagher-Jones, Jihan Zhou, Yuan Hung Lo, Georgian Melinte, Wah Chiu, Jose A Rodriguez, Jianwei Miao
Tomography has made a radical impact on diverse fields ranging from the study of 3D atomic arrangements in matter to the study of human health in medicine. Despite its very diverse applications, the core of tomography remains the same, that is, a mathematical method must be implemented to reconstruct the 3D structure of an object from a number of 2D projections. Here, we present the mathematical implementation of a tomographic algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE), for high-resolution 3D reconstruction from a limited number of 2D projections...
September 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28873456/molecular-prediction-of-lytic-vs-lysogenic-states-for-microcystis-phage-metatranscriptomic-evidence-of-lysogeny-during-large-bloom-events
#20
Joshua M A Stough, Xiangming Tang, Lauren E Krausfeldt, Morgan M Steffen, Guang Gao, Gregory L Boyer, Steven W Wilhelm
Microcystis aeruginosa is a freshwater bloom-forming cyanobacterium capable of producing the potent hepatotoxin, microcystin. Despite increased interest in this organism, little is known about the viruses that infect it and drive nutrient mobilization and transfer of genetic material between organisms. The genomic complement of sequenced phage suggests these viruses are capable of integrating into the host genome, though this activity has not been observed in the laboratory. While analyzing RNA-sequence data obtained from Microcystis blooms in Lake Tai (Taihu, China), we observed that a series of lysogeny-associated genes were highly expressed when genes involved in lytic infection were down-regulated...
2017: PloS One
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