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https://www.readbyqxmd.com/read/29145596/a-crispr-cas9-based-exploration-into-the-elusive-mechanism-for-lactate-export-in-saccharomyces-cerevisiae
#1
Robert Mans, Else-Jasmijn Hassing, Melanie Wijsman, Annabel Giezekamp, Jack T Pronk, Jean-Marc Daran, Antonius J A van Maris
CRISPR/Cas9-based genome editing allows rapid, simultaneous modification of multiple genetic loci in Saccharomyces cerevisiae. Here, this technique was used in a functional analysis study aimed at identifying the hitherto unknown mechanism of lactate export in this yeast. First, an S. cerevisiae strain was constructed with deletions in 25 genes encoding transport proteins, including the complete aqua(glycero)porin family and all known carboxylic-acid transporters. The 25-deletion strain was then transformed with an expression cassette for Lactobacillus casei lactate dehydrogenase (LcLDH)...
November 14, 2017: FEMS Yeast Research
https://www.readbyqxmd.com/read/29145121/role-of-acid-alkali-treatment-in-primary-sludge-anaerobic-fermentation-insights-into-microbial-community-structure-functional-shifts-and-metabolic-output-by-high-throughput-sequencing
#2
Xiao Huang, Wenyi Dong, Hongjie Wang, Yangyang Feng
This study aimed to investigate the effect of acid- or alkali-treatment on volatile fatty acids (VFAs) production and microbiological mechanism during primary sludge anaerobic fermentation. Seven fermentation experiments were conducted at different pH (3-12). Results showed that the optimal pH was 10 for accumulation of VFAs. High-throughput sequencing results indicated that acid and alkali treatment could inhibit Erysipelotrichaceae_UCG-004 and norank_p_Aminicenantes, instead of promoting Pseudomonas and Tissierella at acidic and alkaline condition, respectively...
November 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29143082/spatial-separation-of-photosynthesis-and-ethanol-production-by-cell-type-specific-metabolic-engineering-of-filamentous-cyanobacteria
#3
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
https://www.readbyqxmd.com/read/29142820/excessive-by-product-formation-a-key-contributor-to-low-isobutanol-yields-of-engineered-saccharomyces-cerevisiae-strains
#4
N Milne, S A Wahl, A J A van Maris, J T Pronk, J M Daran
It is theoretically possible to engineer Saccharomyces cerevisiae strains in which isobutanol is the predominant catabolic product and high-yielding isobutanol-producing strains are already reported by industry. Conversely, isobutanol yields of engineered S. cerevisiae strains reported in the scientific literature typically remain far below 10% of the theoretical maximum. This study explores possible reasons for these suboptimal yields by a mass-balancing approach. A cytosolically located, cofactor-balanced isobutanol pathway, consisting of a mosaic of bacterial enzymes whose in vivo functionality was confirmed by complementation of null mutations in branched-chain amino acid metabolism, was expressed in S...
December 2016: Metabolic Engineering Communications
https://www.readbyqxmd.com/read/29142208/transient-increases-in-intracellular-calcium-and-reactive-oxygen-species-levels-in-tcam-2-cells-exposed-to-microgravity
#5
C Morabito, S Guarnieri, A Catizone, C Schiraldi, G Ricci, M A Mariggiò
The effects of microgravity on functions of the human body are well described, including alterations in the male and female reproductive systems. In the present study, TCam-2 cells, which are considered a good model of mitotically active male germ cells, were used to investigate intracellular signalling and cell metabolism during exposure to simulated microgravity, a condition that affects cell shape and cytoskeletal architecture. After a 24 hour exposure to simulated microgravity, TCam-2 cells showed 1) a decreased proliferation rate and a delay in cell cycle progression, 2) increased anaerobic metabolism accompanied by increased levels of intracellular Ca(2+), reactive oxygen species and superoxide anion and modifications in mitochondrial morphology...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29138399/the-industrial-anaerobe-clostridium-acetobutylicum-uses-polyketides-to-regulate-cellular-differentiation
#6
Nicolaus A Herman, Seong Jong Kim, Jeffrey S Li, Wenlong Cai, Hiroyuki Koshino, Wenjun Zhang
Polyketides are an important class of bioactive small molecules valued not only for their diverse therapeutic applications, but also for their role in controlling interesting biological phenotypes in their producing organisms. While numerous polyketides are known to be derived from aerobic organisms, only a single family of polyketides has been identified from anaerobic organisms. Here we uncover a family of polyketides native to the anaerobic bacterium Clostridium acetobutylicum, an organism well-known for its historical use as an industrial producer of the organic solvents acetone, butanol, and ethanol...
November 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/29136935/understanding-azo-dye-anaerobic-bio-decolorization-with-artificial-redox-mediator-supplement-considering-the-methane-production
#7
Ruobin Dai, Xiaoguang Chen, Xinyi Xiang, Yu Wang, Fengbo Wang
Artificial redox mediators (ARM) have been proven to accelerate the azo dye anaerobic bio-reduction (ADAB) but the mechanisms involved are still unclear. Previous studies do seldom focus on the production of methane during the ADAB, particularly if supplemented with ARM. Our studies revealed that the supplement of ARM could significantly accelerate the decolorization rate, recover the inhibited methanogenesis and decrease extracellular polymeric substance secretion in an ADAB system. Supplement of an ARM only enhanced the pre-existing metabolic pathway of the ADAB system...
October 19, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29135970/metabolic-shift-at-the-class-level-sheds-light-on-adaptation-of-methanogens-to-oxidative-environments
#8
Zhe Lyu, Yahai Lu
Methanogens have long been considered strictly anaerobic and oxygen-sensitive microorganisms, but their ability to survive oxygen stress has also been documented. Indeed, methanogens have been found in oxidative environments, and antioxidant genes have been detected in their genomes. How methanogens adapt to oxidative environments, however, remain poorly understood. Here, we systematically predicted and annotated antioxidant features from representative genomes across six well-established methanogen orders...
November 14, 2017: ISME Journal
https://www.readbyqxmd.com/read/29133820/early-postnatal-cardiomyocyte-proliferation-requires-high-oxidative-energy-metabolism
#9
Ana Elisa Teófilo Saturi de Carvalho, Vinícius Bassaneze, Maria Fernanda Forni, Aline Alfonso Keusseyan, Alicia Juliana Kowaltowski, José Eduardo Krieger
Cardiac energy metabolism must cope with early postnatal changes in tissue oxygen tensions, hemodynamics, and cell proliferation to sustain development. Here, we tested the hypothesis that proliferating neonatal cardiomyocytes are dependent on high oxidative energy metabolism. We show that energy-related gene expression does not correlate with functional oxidative measurements in the developing heart. Gene expression analysis suggests a gradual overall upregulation of oxidative-related genes and pathways, whereas functional assessment in both cardiac tissue and cultured cardiomyocytes indicated that oxidative metabolism decreases between the first and seventh days after birth...
November 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29133429/microbial-pathway-for-anaerobic-5-methylthioadenosine-metabolism-coupled-to-ethylene-formation
#10
Justin A North, Anthony R Miller, John A Wildenthal, Sarah J Young, F Robert Tabita
Numerous cellular processes involving S-adenosyl-l-methionine result in the formation of the toxic by-product, 5'-methylthioadenosine (MTA). To prevent inhibitory MTA accumulation and retain biologically available sulfur, most organisms possess the "universal" methionine salvage pathway (MSP). However, the universal MSP is inherently aerobic due to a requirement of molecular oxygen for one of the key enzymes. Here, we report the presence of an exclusively anaerobic MSP that couples MTA metabolism to ethylene formation in the phototrophic bacteria Rhodospirillum rubrum and Rhodopseudomonas palustris In vivo metabolite analysis of gene deletion strains demonstrated that this anaerobic MSP functions via sequential action of MTA phosphorylase (MtnP), 5-(methylthio)ribose-1-phosphate isomerase (MtnA), and an annotated class II aldolase-like protein (Ald2) to form 2-(methylthio)acetaldehyde as an intermediate...
November 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29129679/pecularities-of-the-structure-of-glycogen-as-an-indicator-of-the-functional-state-of-mauthner-neurons-in-fish-perc%C3%B1-ottus-glehni-during-wintering
#11
Irina M Santalova, Rita Ya Gordon, Irina B Mikheeva, Sergei S Khutsian, Eugene I Maevsky
Mauthner neurons (MN)*, specific multifunctional neurons of fish, are a unique object for investigating the adaptive potentialities of the cell. The goal of the work was to study the structure of MN of fish Percсottus glehni during wintering under the conditions of hypothermia and deficit of oxygen and energy substrates. It was shown using a light microscope that the volume of the somatic moiety of neurons changes slightly at the beginning of wintering and is significantly reduced by the termination of wintering...
November 9, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/29128887/the-effect-of-methanogenesis-inhibition-inoculum-and-substrate-concentration-on-hydrogen-and-carboxylic-acids-production-from-cassava-wastewater
#12
Norma C S Amorim, Eduardo L C Amorim, Mario T Kato, Lourdinha Florencio, Savia Gavazza
Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2...
November 11, 2017: Biodegradation
https://www.readbyqxmd.com/read/29127378/first-insights-into-the-pleiotropic-role-of-vrf-yedf-a-newly-characterized-gene-of-salmonella-typhimurium
#13
Clara Ballesté-Delpierre, Dietmar Fernandez-Orth, Mario Ferrer-Navarro, Ramón Díaz-Peña, Antonia Odena-Caballol, Eliandre Oliveira, Anna Fàbrega, Jordi Vila
Salmonella possesses virulence determinants that allow replication under extreme conditions and invasion of host cells, causing disease. Here, we examined four putative genes predicted to encode membrane proteins (ydiY, ybdJ, STM1441 and ynaJ) and a putative transcriptional factor (yedF). These genes were identified in a previous study of a S. Typhimurium clinical isolate and its multidrug-resistant counterpart. For STM1441 and yedF a reduced ability to interact with HeLa cells was observed in the knock-out mutants, but an increase in this ability was absent when these genes were overexpressed, except for yedF which phenotype was rescued when yedF was restored...
November 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29126065/bioconversion-of-alkaloids-to-high-value-chemicals-comparative-analysis-of-newly-isolated-lupanine-degrading-strains
#14
Stella Parmaki, Ioannis Vyrides, Marlen I Vasquez, Viki Hartman, Irene Zacharia, Ioanna Hadjiadamou, Catarina B M Barbeitos, Frederico C Ferreira, Carlos A M Afonso, Chrysoulla Drouza, Michalis Koutinas
This work explores the potential for development of a lupanine valorization process evaluating different isolated microorganisms for their capacity to metabolize the alkaloid. Ecotoxicological assessment demonstrated that lupanine is toxic for Vibrio fischeri and Daphnia magna exhibiting EC50 values of 89 mg L(-1) and 47 mg L(-1) respectively, while acting both as growth inhibitor for a monocotyledonous and as promoter for a dicotyledonous plant. Among the eight aerobic and anaerobic strains isolated and identified Rhodococcus rhodochrous LPK211 achieved 81% removal for 1...
October 30, 2017: Chemosphere
https://www.readbyqxmd.com/read/29126033/natural-attenuation-of-chlorinated-ethenes-in-hyporheic-zones-a-review-of-key-biogeochemical-processes-and-in-situ-transformation-potential
#15
REVIEW
John J Weatherill, Siavash Atashgahi, Uwe Schneidewind, Stefan Krause, Sami Ullah, Nigel Cassidy, Michael O Rivett
Chlorinated ethenes (CEs) are legacy contaminants whose chemical footprint is expected to persist in aquifers around the world for many decades to come. These organohalides have been reported in river systems with concerning prevalence and are thought to be significant chemical stressors in urban water ecosystems. The aquifer-river interface (known as the hyporheic zone) is a critical pathway for CE discharge to surface water bodies in groundwater baseflow. This pore water system may represent a natural bioreactor where anoxic and oxic biotransformation process act in synergy to reduce or even eliminate contaminant fluxes to surface water...
October 30, 2017: Water Research
https://www.readbyqxmd.com/read/29125940/overcoming-the-energetic-limitations-of-syngas-fermentation
#16
REVIEW
Bastian Molitor, Esteban Marcellin, Largus T Angenent
The fermentation of synthesis gas (including carbon monoxide, carbon dioxide, and hydrogen) with anaerobic acetogens is an established biotechnological process that has recently been transferred to a commercial scale. The natural product spectrum of acetogens is natively restricted to acetate, ethanol, and 2,3-butanediol but is rapidly expanding to heterologous products. Syngas fermentation can achieve high carbon-efficiencies; however, the underlying metabolism is operating at a thermodynamic limit. This necessitates special enzymatic properties for energy conservation by acetogens...
November 6, 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/29124514/anaerobic-microplate-assay-for-direct-microbial-conversion-of-switchgrass-and-avicel-using-clostridium-thermocellum
#17
Gbekeloluwa B Oguntimein, Miguel Rodriguez, Alexandru Dumitrache, Todd Shollenberger, Stephen R Decker, Brian H Davison, Steven D Brown
OBJECTIVE: To develop and prototype a high-throughput microplate assay to assess anaerobic microorganisms and lignocellulosic biomasses in a rapid, cost-effective screen for consolidated bioprocessing potential. RESULTS: Clostridium thermocellum parent Δhpt strain deconstructed Avicel to cellobiose, glucose, and generated lactic acid, formic acid, acetic acid and ethanol as fermentation products in titers and ratios similar to larger scale fermentations confirming the suitability of a plate-based method for C...
November 9, 2017: Biotechnology Letters
https://www.readbyqxmd.com/read/29121118/diversity-and-characterization-of-bacteria-associated-with-the-deep-sea-hydrothermal-vent-crab-austinograea-sp-comparing-with-those-of-two-shallow-water-crabs-by-16s-ribosomal-dna-analysis
#18
Na Zhang, Chengwen Song, Minxiao Wang, Yuan Liu, Min Hui, Zhaoxia Cui
For deep-sea hydrothermal vent crabs, recent investigations have revealed some epibiotic bacteria, but no study has described the bacterial community associated with the gill and intestine. In this study, the microbiota attached to the gill and intestine of the hydrothermal vent crab Austinograea sp. and two shallow-water crab species (Eriocheir sinensis and Portunus trituberculatus) were compared by high-throughput sequencing of 16S rDNA genes. The highest and lowest diversity in bacterial communities were observed in the gill and intestine of Austinograea sp...
2017: PloS One
https://www.readbyqxmd.com/read/29120695/hypoxia-and-sprint-swimming-performance-of-juvenile-striped-bass-morone-saxatilis
#19
Krista Kraskura, Jay A Nelson
Annual hypoxia in the Chesapeake Bay has expanded to the point where Darwinian fitness of juvenile striped bass (Morone saxatilis) may depend on their ability to perform in low-oxygen environments. The locomotion they use in predator/prey dynamics relies primarily on white (type II) muscle that is powered by anaerobic metabolic pathways and has generally been thought to be immune to aquatic hypoxia. We tested the sprint performance of 15 juvenile striped bass twice under acute hypoxia (20% air saturation [AS]) 5 wk apart and once under normoxia (>85% AS) in between...
January 2018: Physiological and Biochemical Zoology: PBZ
https://www.readbyqxmd.com/read/29116430/microaerophilic-alkane-degradation-in-pseudomonas-extremaustralis-a-transcriptomic-and-physiological-approach
#20
Paula M Tribelli, Leticia Rossi, Martiniano M Ricardi, Maria Gomez-Lozano, Søren Molin, Laura J Raiger Iustman, Nancy I Lopez
Diesel fuel is one of the most important sources of hydrocarbon contamination worldwide. Its composition consists of a complex mixture of n-alkanes, branched alkanes and aromatic compounds. Hydrocarbon degradation in Pseudomonas species has been mostly studied under aerobic conditions; however, a dynamic spectrum of oxygen availability can be found in the environment. Pseudomonas extremaustralis, an Antarctic bacterium isolated from a pristine environment, is able to degrade diesel fuel and presents a wide microaerophilic metabolism...
November 7, 2017: Journal of Industrial Microbiology & Biotechnology
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