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Sun Young Choi, Sang Jun Sim, Jong-Il Choi, Han Min Woo
To identify microbial squalene that has been widely used in various industrial applications, intracellular formation of photosynthetic squalene was investigated using the previously engineered Synechococcus elongatus PCC 7942 strain. Unlike the proposed localization of squalene in the membrane bilayer, small droplets were identified in the cytoplasm of S. elongatus PCC 7942 as squalene using transmission electron microscopy analysis. Determination of the diameters of the squalene droplets with manual examination of 1,016 droplets in different squalene-producing strains indicated larger squalene droplets in larger cells...
March 12, 2018: Letters in Applied Microbiology
Ginga Shimakawa, Chikahiro Miyake
Oxygenic phototrophs are vulnerable to damage by reactive oxygen species (ROS) that are produced in photosystem I (PSI) by excess photon energy over the demand of photosynthetic CO2 assimilation. In plant leaves, repetitive short-pulse (rSP) illumination produces ROS to inactivate PSI. The production of ROS is alleviated by oxidation of the reaction center chlorophyll in PSI, P700, during the illumination with the short-pulse light, which is supported by flavodiiron protein (FLV). In this study, we found that in the cyanobacterium Synechocystis sp...
March 8, 2018: Photosynthesis Research
Alice Jara De Porcellinis, Hanne Nørgaard, Laura Maria Furelos Brey, Simon Matthé Erstad, Patrik R Jones, Joshua L Heazlewood, Yumiko Sakuragi
Cyanobacteria fix atmospheric CO2 to biomass and through metabolic engineering can also act as photosynthetic factories for sustainable productions of fuels and chemicals. The Calvin Benson cycle is the primary pathway for CO2 fixation in cyanobacteria, algae and C3 plants. Previous studies have overexpressed the Calvin Benson cycle enzymes, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and bifunctional sedoheptulose-1,7-bisphosphatase/fructose-1,6-bisphosphatase (hereafter BiBPase), in both plants and algae, although their impacts on cyanobacteria have not yet been rigorously studied...
March 3, 2018: Metabolic Engineering
Travis C Korosh, Andrew Dutcher, Brian F Pfleger, Katherine D McMahon
Sidestreams in wastewater treatment plants can serve as concentrated sources of nutrients (i.e., nitrogen and phosphorus) to support the growth of photosynthetic organisms that ultimately serve as feedstock for production of fuels and chemicals. However, other chemical characteristics of these streams may inhibit growth in unanticipated ways. Here, we evaluated the use of liquid recovered from municipal anaerobic digesters via gravity belt filtration as a nutrient source for growing the cyanobacterium Synechococcus sp...
January 2018: MSphere
Elena V Kupriyanova, Maria A Sinetova, Vladimir S Bedbenov, Natalia A Pronina, Dmitry A Los
Carbonic anhydrase (CA) EcaA of Synechococcus elongatus PCC 7942 was previously characterized as a putative extracellular α-class CA, however, its activity was never verified. Here we show that EcaA possesses specific CA activity, which is inhibited by ethoxyzolamide. An active EcaA was expressed in heterologous bacterial system, which supports the formation of disulfide bonds, as a full-length protein (EcaA+L) and as a mature protein that lacks a leader peptide (EcaA-L). EcaA-L exhibited higher specific activity compared to EcaA+L...
February 27, 2018: Microbiology
Laura Bretherton, Alicia Williams, Jennifer Genzer, Jessica Hillhouse, Manoj Kamalanathan, Zoe Finkel, Antonietta Quigg
Culture experiments were conducted on ten phytoplankton species to examine their biological and physiological responses during exposure to oil and a combination of oil and dispersant. The species tested included a range of taxa typically found in the Gulf of Mexico such as cyanobacteria, chlorophytes and diatoms. Cultures were exposed to Macondo surrogate oil using the water accommodated fraction (WAF), and dispersed oil using a chemically enhanced WAF (CEWAF) and diluted CEWAF (DCEWAF), to replicate conditions following the Deepwater Horizon spill in the Gulf of Mexico...
February 21, 2018: Journal of Phycology
Fengzheng Gao, Haohao Wu, Mingyong Zeng, Min Huang, Guangxin Feng
BACKGROUND: Inorganic polyphosphate bodies (PPB) have recently been linked to a variety of functions in mammalian cells. To improve the yield of PPB from Synechococcus sp. PCC 7002 and characterize its form, in this study, a recombinant plasmid containing a polyphosphate kinase (ppk) gene was generated and transformed into Synechococcus sp. PCC 7002. RESULTS: PPB separated by Sephadex G-100 was characterized and added to polarized human intestinal epithelial (Caco-2) cells, and the absorption effect was assessed...
February 20, 2018: Microbial Cell Factories
Haihan Zhang, Jingyu Jia, Shengnan Chen, Tinglin Huang, Yue Wang, Zhenfang Zhao, Ji Feng, Huiyan Hao, Sulin Li, Xinxin Ma
The microbial communities associated with algal blooms play a pivotal role in organic carbon, nitrogen and phosphorus cycling in freshwater ecosystems. However, there have been few studies focused on unveiling the dynamics of bacterial and fungal communities during the outbreak and decline of algal blooms in drinking water reservoirs. To address this issue, the compositions of bacterial and fungal communities were assessed in the Zhoucun drinking water reservoir using 16S rRNA and internal transcribed spacer (ITS) gene Illumina MiSeq sequencing techniques...
February 18, 2018: International Journal of Environmental Research and Public Health
Jason T Ku, Ethan I Lan
Using engineered photoautotrophic microorganisms for the direct chemical synthesis from CO2 is an attractive direction for both sustainability and CO2 mitigation. However, the behaviors of non-native metabolic pathways may be difficult to control due to the different intracellular contexts between natural and heterologous hosts. While most metabolic engineering efforts focus on strengthening driving forces in pathway design to favor biochemical production in these organisms, excessive driving force may be detrimental to product biosynthesis due to imbalanced cellular intermediate distribution...
February 17, 2018: Metabolic Engineering
Jin Zhou, Xiao Song, Chun-Yun Zhang, Guo-Fu Chen, Yong-Min Lao, Hui Jin, Zhong-Hua Cai
A central goal in marine microecology is to understand the ecological factors shaping spatiotemporal microbial patterns and the underlying processes. We hypothesized that abiotic and/or biotic interactions are probably more important for explaining the distribution patterns of marine bacterioplankton than environmental filtering. In this study, surface seawater samples were collected about 7000 miles from the Mediterranean Sea, transecting the North Atlantic Ocean, to the Brazilian marginal sea. In bacterial biosphere, SAR11, SAR86, Rhodobacteraceae, and Rhodospiriaceae were predominant in the Mediterranean Sea; Prochlorococcus was more frequent in Atlantic Ocean; whereas in the Brazilian coastal sea, the main bacterial members were Synechococcus and SAR11...
February 14, 2018: Microbial Ecology
Mitsuhiro Itaya, Hiroko Kusakabe, Mitsuru Sato, Masaru Tomita, Rintaro Sato
Synechococcus elongatus PCC7942, a cyanobacterium that uses light and carbon dioxide to grow, has a high ability to incorporate DNA by transformation. To assess the effective delivery of large DNA in plasmid form, we cloned the endogenous plasmid pANL (46.4 kbp) into a BAC vector of Escherichia coli. The plasmid p38ANL (54.3 kbp) replaced the native plasmid. To assess the delivery of larger DNA into PCC7942, p38ANL was fused to the broad-host-range conjugal transfer plasmid pUB307IP (53.5 kbp). The resulting plasmid pUB307IP501 (107...
February 6, 2018: Journal of Biochemistry
Sai Das, Soumen K Maiti
One of the pertinent issues in the field of energy science today is the quest for an abundant source of hydrogen or hydrogen equivalents. In this study, phenyl-p-benzoquinone (pPBQ) has been used to generate a molecular store of hydrogen equivalents (phenyl-p-hydroquinone; pPBQH2) from thein vivo splitting of water by photosystem II of the marine cyanobacterium Synechococcus elongatus BDU 70542. Using this technique, 10.8 μmol of pPBQH2 per mg chlorophyll a can be extracted per minute, an efficiency that is orders of magnitude higher when compared to the techniques present in the current literature...
February 3, 2018: Journal of Photochemistry and Photobiology. B, Biology
Falk Eigemann, Marc Schwartke, Heide Schulz-Vogt
Cyanobacterial blooms regularly occur in the Baltic Sea during the summer months, with filamentous, heterocystous Nodularia spumigena and Dolichospermum sp. and the coccoid picocyanobacterium Synechococcus spp. as important species. Under calm conditions, N. spumigena accumulate at the surface, whereas Dolichospermum sp. and Synechococcus sp. remain at the subsurface, in the upper water layer. This vertical separation allows co-occurring species to compete for the same resources. The factors that determine the vertical distribution within blooms, however, are mostly unknown...
February 2018: Harmful Algae
Erik R Zinser
Hydrogen peroxide (HOOH) is a reactive oxygen species, derived from molecular oxygen, that is capable of damaging microbial cells. Surprisingly, the HOOH defense systems of some aerobes in the oxygenated marine environments are critically depleted, relative to model aerobes. For instance, the gene encoding catalase is absent in the numerically-dominant photosynthetic cyanobacterium, Prochlorococcus. Accordingly, Prochlorococcus is highly susceptible to HOOH when exposed as pure cultures. Pure cultures do not exist in the marine environment, however...
February 6, 2018: Environmental Microbiology Reports
Richard J Puxty, David J Evans, Andrew D Millard, David J Scanlan
Marine cyanobacteria are responsible for ~25% of the fixed carbon that enters the ocean biosphere. It is thought that abundant co-occurring viruses play an important role in regulating population dynamics of cyanobacteria and thus the cycling of carbon in the oceans. Despite this, little is known about how viral infections 'play-out' in the environment, particularly whether infections are resource or energy limited. Photoautotrophic organisms represent an ideal model to test this since available energy is modulated by the incoming light intensity through photophosphorylation...
January 29, 2018: ISME Journal
Gina C Gordon, Jeffrey C Cameron, Brian F Pfleger
RNase III is a ribonuclease that recognizes and cleaves double-stranded RNA. Across bacteria, RNase III is involved in rRNA maturation, CRISPR RNA maturation, controlling gene expression, and turnover of messenger RNAs. Many organisms have only one RNase III while others have both a full-length RNase III and another version that lacks a double-stranded RNA binding domain (mini-III). The genome of the cyanobacterium Synechococcus sp. strain PCC 7002 (PCC 7002) encodes three homologs of RNase III, two full-length and one mini-III, that are not essential even when deleted in combination...
January 24, 2018: Nucleic Acids Research
Katherine Graham, Linsey C Marr, Lauren M Sassoubre, Alexandria B Boehm
We characterized the microbial communities in SSA, water, and sand of three beaches in central California (Cowell Beach, Baker Beach, and Lovers Point) by sequencing the V4 region of the 16S rRNA gene. Average concentrations of 16S rRNA genes in SSA ranged from 2.4 × 104 to 1.4 × 105 gene copies per m3 of air. A total of 9,781 distinct OTUs were identified in SSA and of these, 1,042 OTUs were found in SSA of all beaches. SSA microbial communities included marine taxa, as well as some associated with the terrestrial environment...
January 15, 2018: FEMS Microbiology Ecology
Amr Badary, Shouhei Takamatsu, Mitsuharu Nakajima, Stefano Ferri, Peter Lindblad, Koji Sode
An important feature offered by marine cyanobacterial strains over freshwater strains is the capacity to grow in seawater, replacing the need for often-limited freshwater. However, there are only limited numbers of marine cyanobacteria that are available for genetic manipulation and bioprocess applications. The marine unicellular cyanobacteria Synechococcus sp. strain NKBG 15041c (NKBG15041c) has been extensively studied. Recombinant DNA technologies are available for this strain, and its genomic information has been elucidated...
January 12, 2018: Marine Biotechnology
Blanca Perez-Sepulveda, Frances Pitt, An Ngoc N'Guyen, Morgane Ratin, Laurence Garczarek, Andrew Millard, David J Scanlan
Marine picocyanobacteria of the genus Synechococcus are ubiquitous phototrophs in oceanic systems. Consistent with these organisms occupying vast tracts of the nutrient impoverished ocean, most marine Synechococcus so far studied are monoploid i.e. contain a single chromosome copy. The exception is the oligoploid strain Synechococcus sp. WH7803, which on average possesses around 4 chromosome copies. Here, we set out to understand the role of resource availability (through nutrient deplete growth) and physical stressors (UV, exposure to low and high temperature) in regulating ploidy level in this strain...
January 12, 2018: Environmental Microbiology Reports
Ryan L Clark, Gina C Gordon, Nathaniel R Bennett, Haoxiang Lyu, Thatcher W Root, Brian F Pfleger
As researchers engineer cyanobacteria for biotechnological applications, we must consider potential environmental release of these organisms. Previous theoretical work has considered cyanobacterial containment through elimination of the CO2-concentrating mechanism (CCM) to impose a high-CO2 requirement (HCR), which could be provided in the cultivation environment but not in the surroundings. In this work, we experimentally implemented an HCR containment mechanism in Synechococcus sp. PCC7002 (PCC7002) through deletion of carboxysome shell proteins and showed that this mechanism contained cyanobacteria in a 5% CO2 environment...
January 10, 2018: ACS Synthetic Biology
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