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Adam A Pérez, Bryan H Ferlez, Amanda M Applegate, Karim Walters, Zhihui He, Gaozhong Shen, John H Golbeck, Donald A Bryant
A site-directed C14G mutation was introduced into the stromal PsaC subunit of Synechococcus sp. strain PCC 7002 in vivo in order to introduce an exchangeable coordination site into the terminal FB [4Fe-4S] cluster of Photosystem I (PSI). Using an engineered PSI-less strain (psaAB deletion), psaC was deleted and replaced with recombinant versions controlled by a strong promoter, and the psaAB deletion was complemented. Modified PSI accumulated at lower levels in this strain and supported slower photoautotrophic growth than wild type...
September 15, 2017: Photosynthesis Research
Santhaseelan Henciya, Prabha Seturaman, Arthur Rathinam James, Yi-Hong Tsai, Rahul Nikam, Yang-Chang Wu, Hans-Uwe Dahms, Fang Rong Chang
Prosopis is a commercially important plant genus, which has been used since ancient times, particularly for medicinal purposes. Traditionally, Paste, gum, and smoke from leaves and pods are applied for anticancer, antidiabetic, anti-inflammatory, and antimicrobial purposes. Components of Prosopis such as flavonoids, tannins, alkaloids, quinones, or phenolic compounds demonstrate potentials in various biofunctions, such as analgesic, anthelmintic, antibiotic, antiemetic, microbial antioxidant, antimalarial, antiprotozoal, antipustule, and antiulcer activities; enhancement of H(+), K(+), ATPases; oral disinfection; and probiotic and nutritional effects; as well as in other biopharmaceutical applications, such as binding abilities for tablet production...
January 2017: Journal of Food and Drug Analysis
Franco R Rossi, Adriana R Krapp, Fabiana Bisaro, Santiago J Maiale, Fernando L Pieckenstain, Néstor Carrillo
Reactive oxygen species (ROS) play fundamental roles in plant responses to pathogen infection, including modulation of cell death processes and defense-related gene expression. Cell death triggered as part of the hypersensitive response enhances resistance to biotrophic pathogens, but favors virulence of necrotrophs. Even though the involvement of ROS in the orchestration of defense responses is well established, the relative contribution of specific subcellular ROS sources to plant resistance against microorganisms with different pathogenesis strategies is not completely known...
September 14, 2017: Plant Journal: for Cell and Molecular Biology
Keith Christian, Mirjam Kaestli, Karen Gibb
Photosynthetic microbial communities under translucent rocks (hypolithic) are found in many arid regions. At the global scale, there has been little intercontinental gene flow, and at a local scale, microbial composition is related to fine-scale features of the rocks and their environment. Few studies have investigated patterns of hypolithic community composition at intermediate distances. We examined hypolithic cyanobacterial diversity in semi-arid Australia along a 10-km transect by sampling six rocks from four adjacent 1 m(2) quadrats ("distance zero") and from additional quadrats at 10, 100, 1,000, and 10,000 m to test the hypothesis that diversity would increase with the number of rocks sampled and distance...
September 2017: Ecology and Evolution
Petr Vítek, Carmen Ascaso, Octavio Artieda, María Cristina Casero, Jacek Wierzchos
The biochemical responses of rock-inhabiting cyanobacteria towards native environmental stresses were observed in vivo in one of the Earth's most challenging extreme climatic environments. The cryptoendolithic cyanobacterial colonization, dominated by Chroococcidiopsis sp., was studied in an ignimbrite at a high altitude volcanic area in the Atacama Desert, Chile. Change in the carotenoid composition (red-shift) within a transect through the cyanobacteria dominant microbial community (average thickness ~1 mm) was unambiguously revealed in their natural endolithic microhabitat...
September 11, 2017: Scientific Reports
Wenjia Gu, Eric W Schmidt
Natural products are significant therapeutic agents and valuable drug leads. This is likely owing to their three-dimensional structural complexity, which enables them to form complex interactions with biological targets. Enzymes from natural product biosynthetic pathways show great potential to generate natural product-like compounds and libraries. Many challenges still remain in biosynthesis, such as how to rationally synthesize small molecules with novel structures and how to generate maximum chemical diversity...
September 11, 2017: Accounts of Chemical Research
Damian Drzyzga, Jacek Lipok
Aminopolyphosphonates (AAPs) are commonly used industrial complexones of metal ions, which upon the action of biotic and abiotic factors undergo a breakdown and release their substructures. Despite the low toxicity of AAPs towards vertebrates, products of their transformations, especially those that contain phosphorus and nitrogen, can affect algal communities. To verify whether such chemical entities are present in water ecosystems, much effort has been made in developing fast, inexpensive, and reliable methods for analyzing phosphonates...
September 10, 2017: Environmental Science and Pollution Research International
Veronika Angerer, Lars-Oliver Essen, Annegret Wilde
Diguanylate cyclases are enzymes that use two GTP molecules to produce one molecule cyclic dimeric guanosine monophosphate (c-di-GMP). This cyclic dinucleotide is an ubiquitous prokaryotic second messenger that controls a variety of cell functions. Several proteins have been described which contain a photoreceptor domain fused to a diguanylate cyclase. The cyanobacterial light sensor Cph2 is responsible for the blue-light induced synthesis of c-di-GMP in Synechocystis sp. PCC 6803. Here, we provide a detailed protocol for an in vitro enzymatic assay with a purified photoreceptor protein using light as the crucial reaction parameter for c-di-GMP synthesis...
2017: Methods in Molecular Biology
Lee C Bowling, Mustak Shaikh, John Brayan, Tim Malthus
A commercially available handheld spectroradiometer, the WISP-3, was assessed as a tool for monitoring freshwater cyanobacterial blooms for management purposes. Three small eutrophic urban ponds which displayed considerable within-pond and between-pond variability in water quality and cyanobacterial community composition were used as trial sites. On-board algorithms provide field measurements of phycocyanin (CPC) and chlorophyll-a (Chl-a) from surface reflectance spectra measured by the instrument. These were compared with laboratory measurements...
September 9, 2017: Environmental Monitoring and Assessment
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
Noura El-Ahmady El-Naggar, Mervat H Hussein, Asmaa Atallah El-Sawah
In recent decades, researchers were attracted towards cyanobacterial components which are potential low-cost biological reagents for silver nanoparticle biosynthesis. This article describes the biological synthesis of silver nanoparticles using a proteinaceous pigment phycocyanin extracted from Nostoc linckia as reducing agent. The synthesized silver nanoparticles have a surface plasmon resonance band centered at 425 nm. Face-centered central composite design used for optimization of silver nanoparticles (AgNPs) biosynthesis using phycocyanin...
September 7, 2017: Scientific Reports
Anupama Lakshmanan, George J Lu, Arash Farhadi, Suchita P Nety, Martin Kunth, Audrey Lee-Gosselin, David Maresca, Raymond W Bourdeau, Melissa Yin, Judy Yan, Christopher Witte, Dina Malounda, F Stuart Foster, Leif Schröder, Mikhail G Shapiro
Gas vesicles (GVs) are a unique class of gas-filled protein nanostructures that are detectable at subnanomolar concentrations and whose physical properties allow them to serve as highly sensitive imaging agents for ultrasound and MRI. Here we provide a protocol for isolating GVs from native and heterologous host organisms, functionalizing these nanostructures with moieties for targeting and fluorescence, characterizing their biophysical properties and imaging them using ultrasound and MRI. GVs can be isolated from natural cyanobacterial and haloarchaeal host organisms or from Escherichia coli expressing a heterologous GV gene cluster and purified using buoyancy-assisted techniques...
October 2017: Nature Protocols
Anthony Laugeray, Asma Oummadi, Clément Jourdain, Justyne Feat, Géraldine Meyer-Dilhet, Arnaud Menuet, Karen Plé, Marion Gay, Sylvain Routier, Stéphane Mortaud, Gilles J Guillemin
We recently demonstrated that perinatal exposure to the glutamate-related herbicide, glufosinate ammonium, has deleterious effects on neural stem cell (NSC) homeostasis within the sub-ventricular zone (SVZ), probably leading to ASD-like symptoms in offspring later in life. In the present study, we aimed to investigate whether perinatal exposure to another glutamate-related toxicant, the cyanobacterial amino acid β-N-methylamino-L-alanine (BMAA), might also trigger neurodevelopmental disturbances. With this aim, female mice were intranasally exposed to low doses of BMAA, 50 mg kg(-1) three times a week from embryonic days 7-10 to postnatal day 21...
September 6, 2017: Neurotoxicity Research
Ashleigh R Currie, Karen Tait, Helen Parry, Beatriz de Francisco-Mora, Natalie Hicks, A Mark Osborn, Steve Widdicombe, Henrik Stahl
Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2) and elevated temperature (ambient +4°C) on the abundance of taxonomic and functional microbial genes...
2017: Frontiers in Microbiology
Danillo Oliveira Alvarenga, Ana Paula Dini Andreote, Luis Henrique Zanini Branco, Marli Fatima Fiore
Tropical ecosystems worldwide host very diverse microbial communities, but are increasingly threatened by deforestation and climate change. Thus, characterization of biodiversity in these environments, and especially of microbial communities that show unique adaptations to their habitats, is a very urgent matter. Information about representatives of the phylum Cyanobacteria in tropical environments is scarce, even though they are fundamental primary producers that help other microbes to thrive in nutrient-depleted habitats, including phyllospheres...
September 6, 2017: International Journal of Systematic and Evolutionary Microbiology
Nathan Torbick, Beth Ziniti, Elijah Stommel, Ernst Linder, Angeline Andrew, Tracie Caller, Jim Haney, Walter Bradley, Patricia L Henegan, Xun Shi
No abstract text is available yet for this article.
September 5, 2017: Neurotoxicity Research
Angela Zhang, Austin L Carroll, Shota Atsumi
Atmospheric CO2 levels have reached an alarming level due to industrialization and the burning of fossil fuels. In order to lower the level of atmospheric carbon, strategies to sequester excess carbon need to be implemented. The CO2-fixing mechanism in photosynthetic organisms enables integration of atmospheric CO2 into biomass. Additionally, through exogenous metabolic pathways in these photosynthetic organisms, fixed CO2 can be routed to produce various commodity chemicals that are currently produced from petroleum...
September 1, 2017: FEMS Microbiology Letters
Aurelia Chenu, Nir Keren, Yossi Paltiel, Reinat Nevo, Ziv Reich, Jianshu Cao
Phycobilisomes, the light-harvesting antennas of cyanobacteria, can adapt to a wide range of environments thanks to a composition and function response to stress conditions. We study how structural changes influence excitation transfer in these super-complexes. Specifically, we show the influence of the rod length on the photon absorption and subsequent excitation transport to the core. Despite the fact that the efficiency of individual disks on the rod decreases with increasing rod length, we find an optimal length for which the average rod efficiency is maximal...
September 5, 2017: Journal of Physical Chemistry. B
Shobit Thapa, Radha Prasanna, Kunal Ranjan, Kulandaivelu Velmourougane, Balasubramanian Ramakrishnan
The abundance of phyllosphere bacterial communities of seven genotypes of rice ADT- 38, ADT-43, CR-1009, PB-1, PS-5, P-44, and PB-1509 was investigated, in relation to nutrient dynamics of rhizosphere and leaves. P-44 genotype recorded highest pigment accumulation, while genotypes CR-1009 and P-44 exhibited most number of different bacterial morphotypes, Colony forming units in two media (Nutrient agar and R2A) varied significantly and ranged from 10(6)-10(7) per g plant tissues. Among the selected 60 distinct morphotypes, IAA and siderophore producers were the dominant functional types...
November 2017: Microbiological Research
J Kosiba, W Krztoń, E Wilk-Woźniak
The increasing proliferation of cyanobacterial blooms prolongs the impact of cyanobacteria on aquatic fauna, potentially altering trophic relationships. We hypothesized that any effect of dissolved microcystins (toxins produced by cyanobacteria) on plankton assemblages would be more evident in artificial reservoirs and ponds than in natural ones. The concentrations of dissolved microcystins in the waters we studied ranged widely from 0.07 to 0.81 μg/L. We showed that the artificial ponds were subjected to more frequent and longer-lasting harmful algal blooms...
September 2, 2017: Microbial Ecology
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