keyword
MENU ▼
Read by QxMD icon Read
search

chemostat

keyword
https://www.readbyqxmd.com/read/28928722/fermentative-bacteria-influence-the-competition-between-denitrifiers-and-dnra-bacteria
#1
Eveline M van den Berg, Marina P Elisário, J Gijs Kuenen, Robbert Kleerebezem, Mark C M van Loosdrecht
Denitrification and dissimilatory reduction to ammonium (DNRA) are competing nitrate-reduction processes that entail important biogeochemical consequences for nitrogen retention/removal in natural and man-made ecosystems. The nature of the available carbon source and electron donor have been suggested to play an important role on the outcome of this microbial competition. In this study, the influence of lactate as fermentable carbon source on the competition for nitrate was investigated for varying ratios of lactate and nitrate in the influent (Lac/N ratio)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28900755/quantitative-physiology-and-elemental-composition-of-kluyveromyces-lactis-cbs-2359-during-growth-on-glucose-at-different-specific-growth-rates
#2
Oscar Dias, Thiago O Basso, Isabel Rocha, Eugénio C Ferreira, Andreas K Gombert
The yeast Kluyveromyces lactis has received attention both from academia and industry due to some important features, such as its capacity to grow in lactose-based media, its safe status, its suitability for large-scale cultivation and for heterologous protein synthesis. It has also been considered as a model organism for genomics and metabolic regulation. Despite this, very few studies were carried out hitherto under strictly controlled conditions, such as those found in a chemostat. Here we report a set of quantitative physiological data generated during chemostat cultivations with the K...
September 12, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28892295/transcriptome-and-proteome-dynamics-in-chemostat-culture-reveal-how-campylobacter-jejuni-modulates-metabolism-stress-responses-and-virulence-factors-upon-changes-in-oxygen-availability
#3
Edward J Guccione, John J Kendall, Andrew Hitchcock, Nitanshu Garg, Michael A White, Francis Mulholland, Robert K Poole, David J Kelly
Campylobacter jejuni, the most frequent cause of food-borne bacterial gastroenteritis worldwide, is a microaerophile that has to survive high environmental oxygen tensions, adapt to oxygen limitation in the intestine and resist host oxidative attack. Here, oxygen-dependent changes in C. jejuni physiology were studied at constant growth rate using carbon (serine)-limited continuous chemostat cultures. We show that a perceived aerobiosis scale can be calibrated by the acetate excretion flux, which becomes zero when metabolism is fully aerobic (100% aerobiosis)...
September 11, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28879478/influence-of-oxygen-availability-on-the-metabolism-and-morphology-of-yarrowia-lipolytica-insights-into-the-impact-of-glucose-levels-on-dimorphism
#4
Asma Timoumi, Carine Bideaux, Stéphane E Guillouet, Yohan Allouche, Carole Molina-Jouve, Luc Fillaudeau, Nathalie Gorret
Dynamic behavior of Yarrowia lipolytica W29 strain under conditions of fluctuating, low, and limited oxygen supply was characterized in batch and glucose-limited chemostat cultures. In batch cultures, transient oscillations between oxygen-rich and -deprived environments induced a slight citric acid accumulation (lower than 29 mg L(-1)). By contrast, no citric acid was detected in continuous fermentations for all stress conditions: full anoxia (zero pO2 value, 100% N2), limited (zero pO2 value, 75% of cell needs), and low (pO2 close to 2%) dissolved oxygen (DO) levels...
September 6, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28865116/power-input-effects-on-degeneration-in-prolonged-penicillin-chemostat-cultures-a-systems-analysis-at-flux-residual-glucose-metabolite-and-transcript-levels
#5
Guan Wang, Baofeng Wu, Junfei Zhao, Cees Haringa, Jianye Xia, Ju Chu, Yingping Zhuang, Siliang Zhang, Joseph J Heijnen, Walter van Gulik, Amit T Deshmukh, Henk J Noorman
In the present work, by performing chemostat experiments at 400 and 600 RPM, two typical power inputs representative of industrial penicillin fermentation (P/V, 1.00 kW/m(3) in more remote zones and 3.83 kW/m(3) in the vicinity of the impellers, respectively) were scaled-down to bench-scale bioreactors. It was found that at 400 RPM applied in prolonged glucose-limited chemostat cultures, the previously reported degeneration of penicillin production using an industrial Penicillium chrysogenum strain was virtually absent...
September 2, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28854670/optimization-of-therapy-against-pseudomonas-aeruginosa-with-ceftazidime-and-meropenem-using-chemostats-as-model-for-infections
#6
Yanfang Feng, Reinier M van Hest, Caspar J Hodiamont, Stanley Brul, Constance Schultsz, Benno H Ter Kuile
Pseudomonas aeruginosa is an opportunistic pathogen that can cause life-threatening infections in patients admitted to intensive care units. Resistance rapidly develops against two drugs of choice: ceftazidime and meropenem. Several therapeutic protocols were compared for reduction in viable cells and limiting development of resistance. Chemostat cultures were exposed to antibiotic concentrations measured in the blood of patients at low (5th percentile), medium (50th percentile) or high (95th percentile) levels in several therapy protocols to simulate therapy...
August 1, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28844132/single-cell-microfluidics-to-study-the-effects-of-genome-deletion-on-bacterial-growth-behaviour
#7
Xiaofei Yuan, Jillian M Couto, Andrew Glidle, Yanqing Song, William Sloan, Huabing Yin
By directly monitoring single cell growth in a microfluidic platform, we interrogated genome-deletion effects in Escherichia coli strains. We compared the growth dynamics of a wild type strain with a clean genome strain, and their derived mutants at the single-cell level. A decreased average growth rate and extended average lag time were found for the clean genome strain, compared to those of the wild type strain. Direct correlation between the growth rate and lag time of individual cells showed that the clean genome population was more heterogeneous...
August 26, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28840937/impact-of-growth-mode-phase-and-rate-on-the-metabolic-state-of-the-extremely-thermophilic-archaeon-pyrococcus-furiosus
#8
Piyum A Khatibi, Chung-Jung Chou, Andrew J Loder, Jeffrey V Zurawski, Michael W W Adams, Robert M Kelly
The archaeon Pyrococcus furiosus is emerging as a metabolic engineering platform for production of fuels and chemicals, such that more must be known about this organism's characteristics in bioprocessing contexts. Its ability to grow at temperatures from 70 to greater than 100°C and thereby avoid contamination, offers the opportunity for long duration, continuous bioprocesses as an alternative to batch systems. Towards that end, we analyzed the transcriptome of P. furiosus to reveal its metabolic state during different growth modes that are relevant to bioprocessing...
August 25, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28822912/a-metabolic-activity-detecting-approach-to-life-detection-restoring-a-chemostat-from-stop-feeding-using-a-rapid-bioactivity-assay
#9
Shiue-Lin Li, Ming-Der Bai, Chia-Jung Hsiao, Sheng-Shung Cheng, Kenneth H Nealson
A mediated glassy carbon electrode covered by a thin-film polyviologen was used in the present study to rapidly detect bioactivity in a mixed-culture chemostat (dominated by Clostridium sp.). With the addition of 1mM hexacyanoferrate and 9mM glucose, the current increasing rate (dI/dt) measured under a poised potential of 500mV (vs. Ag/AgCl) can be defined as the quantity of metabolic activity. In the experiment of restoring the chemostat from stop-feeding, it is suggested that when the dI/dt was >2μAmin(-1), the influent pump could be directly turned on to maintain the high dilution rate of 0...
August 9, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/28810216/light-intensity-as-major-factor-to-maximize-biomass-and-lipid-productivity-of-ettlia-sp-in-co2-controlled-photoautotrophic-chemostat
#10
Seong-Hyun Seo, Ji-San Ha, Chan Yoo, Ankita Srivastava, Chi-Yong Ahn, Dae-Hyun Cho, Hyun-Joon La, Myung-Soo Han, Hee-Mock Oh
The optimal culture conditions are critical factors for high microalgal biomass and lipid productivity. To optimize the photoautotrophic culture conditions, combination of the pH (regulated by CO2 supply), dilution rate, and light intensity was systematically investigated for Ettlia sp. YC001 cultivation in a chemostat during 143days. The biomass productivity increased with the increase in dilution rate and light intensity, but decreased with increasing pH. The average lipid content was 19.8% and statistically non-variable among the tested conditions...
November 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28801639/investigation-into-the-stability-and-culturability-of-chinese-enterotypes
#11
Yeshi Yin, Bin Fan, Wei Liu, Rongrong Ren, Huahai Chen, Shaofeng Bai, Liying Zhu, Gang Sun, Yunsheng Yang, Xin Wang
Although many gut microbial enterotypes have been reported in Europe, Africa and the U.S., their effects on human health are still not yet clear. Culturing gut microbial enterotypes in vitro will be helpful to study their effects and applications. Here, fecal samples from 13 healthy Chinese volunteers were collected and subjected to next-generation sequencing. The results showed that seven of these samples belong to the Bacteroides enterotype and another six to the Prevotella enterotype. Stability of these Chinese gut microbial enterotypes was also evaluated...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28776272/concurrent-metabolism-of-pentose-and-hexose-sugars-by-the-polyextremophile-alicyclobacillus-acidocaldarius
#12
Brady D Lee, William A Apel, Linda C DeVeaux, Peter P Sheridan
Alicyclobacillus acidocaldarius is a thermoacidophilic bacterium capable of growth on sugars from plant biomass. Carbon catabolite repression (CCR) allows bacteria to focus cellular resources on a sugar that provides efficient growth, but also allows sequential, rather than simultaneous use when more than one sugar is present. The A. acidocaldarius genome encodes all components of CCR, but transporters encoded are multifacilitator superfamily and ATP-binding cassette-type transporters, uncommon for CCR. Therefore, global transcriptome analysis of A...
August 3, 2017: Journal of Industrial Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28770068/evolutionary-implications-of-liebig-s-law-of-the-minimum-selection-under-low-concentrations-of-two-nonsubstitutable-nutrients
#13
Omar M Warsi, Daniel E Dykhuizen
Interactions between different axes of an organism's niche determine the evolutionary trajectory of a population. An extreme case of these interactions is predicted from ecological theory in Liebig's law of the minimum. This law states that in environments where multiple nutrients are in relatively low concentrations, only one nutrient will affect the growth of the organism. This implies that the evolutionary response of the population would be dictated by the most growth-limiting nutrient. Alternatively, it is possible that an initial adaptation to the most limiting nutrient results in other nutrients present in low concentration affecting the evolutionary dynamics of the population...
July 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28760443/self-cycling-fermentation-for-1-3-propanediol-production-comparative-evaluation-of-metabolite-flux-in-cell-recycling-simple-batch-and-continuous-processes-using-lactobacillus-brevis-n1e9-3-3-strain
#14
Narisetty Vivek, T V Aswathi, Petit Riff Sven, Ashok Pandey, Parameswaran Binod
The microbial conversion of biodiesel derived crude glycerol to 1,3-propanediol (1,3-PDO) has attained high industrial value due to the broad range of applications as a monomer (1,3-PDO) in textile, cosmetic and polymer industries. This fine chemical through biological production addressed several limitations of the chemical process like high temperatures, pressure and expensive catalysts. In this study 1,3-propanediol production was achieved from a non-pathogenic lactic acid bacterial strain Lactobacillus brevis N1E9...
July 29, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28747905/from-ecological-stoichiometry-to-biochemical-composition-variation-in-n-and-p-supply-alters-key-biosynthetic-rates-in-marine-phytoplankton
#15
Julia Grosse, Amanda Burson, Maayke Stomp, Jef Huisman, Henricus T S Boschker
One of the major challenges in ecological stoichiometry is to establish how environmental changes in resource availability may affect both the biochemical composition of organisms and the species composition of communities. This is a pressing issue in many coastal waters, where anthropogenic activities have caused large changes in riverine nutrient inputs. Here we investigate variation in the biochemical composition and synthesis of amino acids, fatty acids (FA), and carbohydrates in mixed phytoplankton communities sampled from the North Sea...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28726375/nanoscale-hydrodynamic-film-for-diffusive-mass-transport-control-in-compartmentalized-microfluidic-chambers
#16
Minseok Kim, Ji Won Lim, Sung Kuk Lee, Taesung Kim
A compartmentalized microfluidic chamber array that offers not only separate cell culture environments but also independent control of the diffusion of small molecules provides an extremely useful platform for cell cultivations and versatile cellular assays. However, it is challenging to incorporate both cell compartmentalization and active diffusion control in real-time and precise manners. Here, we present a novel nanoscale hydrodynamic film (NHF) that is formed between a solid substrate and a polydimethylsiloxane (PDMS) surface...
August 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28720731/an-in-vitro-chicken-gut-model-demonstrates-transfer-of-a-multidrug-resistance-plasmid-from-salmonella-to-commensal-escherichia-coli
#17
Roderick M Card, Shaun A Cawthraw, Javier Nunez-Garcia, Richard J Ellis, Gemma Kay, Mark J Pallen, Martin J Woodward, Muna F Anjum
The chicken gastrointestinal tract is richly populated by commensal bacteria that fulfill various beneficial roles for the host, including helping to resist colonization by pathogens. It can also facilitate the conjugative transfer of multidrug resistance (MDR) plasmids between commensal and pathogenic bacteria which is a significant public and animal health concern as it may affect our ability to treat bacterial infections. We used an in vitro chemostat system to approximate the chicken cecal microbiota, simulate colonization by an MDR Salmonella pathogen, and examine the dynamics of transfer of its MDR plasmid harboring several genes, including the extended-spectrum beta-lactamase blaCTX-M1 We also evaluated the impact of cefotaxime administration on plasmid transfer and microbial diversity...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28717043/tandem-amplification-of-the-staphylococcal-cassette-chromosome-mec-element-can-drive-high-level-methicillin-resistance-in-methicillin-resistant-staphylococcus-aureus
#18
Laura A Gallagher, Simone Coughlan, Nikki S Black, Pierce Lalor, Elaine M Waters, Bryan Wee, Mick Watson, Tim Downing, J Ross Fitzgerald, Gerard T A Fleming, James P O'Gara
Hospital-associated methicillin-resistant Staphylococcus aureus (MRSA) strains typically express high-level, homogeneous (HoR) β-lactam resistance, whereas community-associated MRSA (CA-MRSA) more commonly express low-level heterogeneous (HeR) resistance. Expression of the HoR phenotype typically requires both increased expression of the mecA gene, carried on the staphylococcal cassette chromosome mec element (SCCmec), and additional mutational event(s) elsewhere on the chromosome. Here the oxacillin concentration in a chemostat culture of the CA-MRSA strain USA300 was increased from 8 μg/ml to 130 μg/ml over 13 days to isolate highly oxacillin-resistant derivatives...
September 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28709972/generalised-approach-to-modelling-a-three-tiered-microbial-food-web
#19
T Sari, M J Wade
The complexity of the anaerobic digestion process has motivated the development of complex models, such as the widely used Anaerobic Digestion Model No. 1. However, this complexity makes it intractable to identify the stability profile coupled to the asymptotic behaviour of existing steady-states as a function of conventional chemostat operating parameters (substrate inflow concentration and dilution rate). In a previous study this model was simplified and reduced to its very backbone to describe a three-tiered chlorophenol mineralising food-web, with its stability analysed numerically using consensus values for the various biological parameters of the Monod growth functions...
September 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/28680423/control-of-sulfide-production-in-high-salinity-bakken-shale-oil-reservoirs-by-halophilic-bacteria-reducing-nitrate-to-nitrite
#20
Biwen A An, Yin Shen, Gerrit Voordouw
Microbial communities in shale oil fields are still poorly known. We obtained samples of injection, produced and facility waters from a Bakken shale oil field in Saskatchewan, Canada with a resident temperature of 60°C. The injection water had a lower salinity (0.7 Meq of NaCl) than produced or facility waters (0.6-3.6 Meq of NaCl). Salinities of the latter decreased with time, likely due to injection of low salinity water, which had 15-30 mM sulfate. Batch cultures of field samples showed sulfate-reducing and nitrate-reducing bacteria activities at different salinities (0, 0...
2017: Frontiers in Microbiology
keyword
keyword
103881
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"