scholarly journals Optimizing bioreactor growth of the smallest eukaryote

2018 ◽  
Author(s):  
Chuck R. Smallwood ◽  
Eric A. Hill ◽  
William Chrisler ◽  
Jory Brookreson ◽  
James E. Evans
Keyword(s):  
Growth Conditions ◽  
Energy Resources ◽  
Total Biomass ◽  
Nutrient Requirements ◽  
Free Living ◽  
Nutrient Pools ◽  
Photosynthetic Organisms ◽  
Ostreococcus Tauri ◽  
Phototrophic Growth ◽  
Doubling Times

AbstractPhotosynthetic organisms are adept at circumventing nutrient deprivation. Microalgae in particular present novel adaptations to nutrient and light starvation since they can scavenge external and internal nutrient pools to redistribute energy resources for survival. In this report, a turbidostatic photobioreactor was used to characterize environmental conditions and nutrient requirements for cultures of the smallest free-living eukaryote Ostreococcus tauri. Optimized growth conditions were identified that enable 4-times faster phototrophic growth-rates while increasing total biomass 10-fold. By achieving phototrophic doubling times shorter than 6 hours, these results highlight the potential of this smallest eukaryote for future industrial bioproduct applications.

scholarly journals Paraburkholderia phymatum Homocitrate Synthase NifV Plays a Key Role for Nitrogenase Activity during Symbiosis with Papilionoids and in Free-Living Growth Conditions

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 952
Author(s):  
Paula Bellés-Sancho ◽  
Martina Lardi ◽  
Yilei Liu ◽  
Sebastian Hug ◽  
Marta Adriana Pinto-Carbó ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Growth Conditions ◽  
Lysine Biosynthesis ◽  
Metabolome Analysis ◽  
Plant Host ◽  
Free Living ◽  
Bacterial Enzyme ◽  
Homocitrate Synthase ◽  
Iron Molybdenum Cofactor

Homocitrate is an essential component of the iron-molybdenum cofactor of nitrogenase, the bacterial enzyme that catalyzes the reduction of dinitrogen (N2) to ammonia. In nitrogen-fixing and nodulating alpha-rhizobia, homocitrate is usually provided to bacteroids in root nodules by their plant host. In contrast, non-nodulating free-living diazotrophs encode the homocitrate synthase (NifV) and reduce N2 in nitrogen-limiting free-living conditions. Paraburkholderia phymatum STM815 is a beta-rhizobial strain, which can enter symbiosis with a broad range of legumes, including papilionoids and mimosoids. In contrast to most alpha-rhizobia, which lack nifV, P. phymatum harbors a copy of nifV on its symbiotic plasmid. We show here that P. phymatum nifV is essential for nitrogenase activity both in root nodules of papilionoid plants and in free-living growth conditions. Notably, nifV was dispensable in nodules of Mimosa pudica despite the fact that the gene was highly expressed during symbiosis with all tested papilionoid and mimosoid plants. A metabolome analysis of papilionoid and mimosoid root nodules infected with the P. phymatum wild-type strain revealed that among the approximately 400 measured metabolites, homocitrate and other metabolites involved in lysine biosynthesis and degradation have accumulated in all plant nodules compared to uninfected roots, suggesting an important role of these metabolites during symbiosis.

scholarly journals Altering Tetrapyrrole Biosynthesis by Overexpressing Ferrochelatases (Fc1 and Fc2) Improves Photosynthetic Efficiency in Transgenic Barley

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1370
Author(s):  
Dilrukshi S. K. Nagahatenna ◽  
Jingwen Tiong ◽  
Everard J. Edwards ◽  
Peter Langridge ◽  
Ryan Whitford
Keyword(s):  
Stomatal Conductance ◽  
Photosynthetic Efficiency ◽  
Catalytic Domain ◽  
Growth Conditions ◽  
Photosynthetic Performance ◽  
Tetrapyrrole Biosynthesis ◽  
Hordeum Vulgare L ◽  
Yield Performance ◽  
Photosynthetic Organisms ◽  
Transgenic Barley

Ferrochelatase (FC) is the terminal enzyme of heme biosynthesis. In photosynthetic organisms studied so far, there is evidence for two FC isoforms, which are encoded by two genes (FC1 and FC2). Previous studies suggest that these two genes are required for the production of two physiologically distinct heme pools with only FC2-derived heme involved in photosynthesis. We characterised two FCs in barley (Hordeum vulgare L.). The two HvFC isoforms share a common catalytic domain, but HvFC2 additionally contains a C-terminal chlorophyll a/b binding (CAB) domain. Both HvFCs are highly expressed in photosynthetic tissues, with HvFC1 transcripts also being abundant in non-photosynthetic tissues. To determine whether these isoforms differentially affect photosynthesis, transgenic barley ectopically overexpressing HvFC1 and HvFC2 were generated and evaluated for photosynthetic performance. In each case, transgenics exhibited improved photosynthetic rate (Asat), stomatal conductance (gs) and carboxylation efficiency (CE), showing that both FC1 and FC2 play important roles in photosynthesis. Our finding that modified FC expression can improve photosynthesis up to ~13% under controlled growth conditions now requires further research to determine if this can be translated to improved yield performance under field conditions.

scholarly journals Growth and Amino Acid Requirements of Various Strains of Group B Streptococci

1978 ◽  
Vol 7 (1) ◽  
pp. 28-33
Author(s):  
Thomas W. Milligan ◽  
Terence I. Doran ◽  
David C. Straus ◽  
Stephen J. Mattingly
Keyword(s):  
Amino Acid ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Clinical Isolates ◽  
Group B Streptococci ◽  
Amino Acid Requirements ◽  
Group B ◽  
Doubling Times ◽  
Aerobic And Anaerobic Growth ◽  
Aerobic And Anaerobic

A chemically defined medium (FMC; B. Terleckyj, N. P. Willett, and G. D. Shockman, Infect. Immun. 11 :649-655, 1975) was used to compare the growth and amino acid requirements of 16 strains of group B streptococci, consisting of both laboratory-passaged organisms and fresh clinical isolates from adult and neonatal infections. The 5 standard Lancefield immunizing strains of group B streptococci, 090 (Ia), H36B (Ib), A909 (Ic), 18RS21 (II), and D136C (III), had doubling times in FMC (28 to 36 min) similar to those observed in Todd-Hewitt glucose broth (24 to 30 min). Similar doubling times were obtained with 11 clinical isolates growing in Todd-Hewitt glucose broth and FMC. The optimum buffering capacity of FMC was provided by 0.06 M sodium phosphate, and 1% glucose gave maximum cell yield. The group B streptococci, with minor exceptions, were very homogeneous in their amino acid requirements under both aerobic and anaerobic growth conditions. Phenylalanine, tyrosine, tryptophan, glutamate, arginine, valine, leucine, lysine, methionine, isoleucine, cystine, and histidine were required by all 16 strains under both aerobic and anaerobic growth conditions. In addition, threonine was required by all strains under aerobic growth conditions, whereas only 9 strains required threonine under anaerobic conditions. Serine was required by only 3 type III fresh clinical isolates aerobically, but not anaerobically. A requirement for glycine varied from strain to strain, apparently influenced by the oxidation-reduction potential of the growth medium.

scholarly journals Functional and Structural Characterization of a Novel Isoamylase from Ostreococcus tauri and Role of the N-Terminal Domain

2020 ◽  
Vol 14 (1) ◽  
pp. 1-11
Author(s):  
Nicolas Hedín ◽  
Julieta Barchiesi ◽  
Diego F. Gomez-Casati ◽  
María V. Busi
Keyword(s):  
Crystallization Process ◽  
Biochemical Characterization ◽  
Carbohydrate Binding ◽  
Amino Acid Residues ◽  
Photosynthetic Organisms ◽  
Ostreococcus Tauri ◽  
The Family ◽  
Almost All

Background: The debranching starch enzymes, isoamylase 1 and 2 are well-conserved enzymes present in almost all the photosynthetic organisms. These enzymes are involved in the crystallization process of starch and are key components which remove misplaced α-1,6 ramifications on the final molecule. Aim: In this work, we performed a functional and structural study of a novel isoamylase from Ostreococcus tauri. Methods: We identified conserved amino acid residues possibly involved in catalysis. We also identified a region at the N-terminal end that resembles a Carbohydrate Binding Domain (CBM), which is more related to the family CBM48, but has no spatial conservation of the residues involved in carbohydrate binding. Results: The cloning, expression and biochemical characterization of this N-terminal region confirmed that it binds to polysaccharides, showing greater capacity for binding to amylopectin rather than total starch or amylose. Conclusion: This module could be a variant of the CBM48 family or it could be classified within a new CBM family.

Differentiation of the membrane system in cells of Rhodopseudomonas capsulata after transition from chemotrophic to phototrophic growth conditions

1982 ◽  
Vol 131 (4) ◽  
pp. 313-322 ◽  
Author(s):  
Norbert Kaufmann ◽  
Horst-Helwig Reidl ◽  
Jochen R. Golecki ◽  
Augusto F. Garcia ◽  
Gerhart Drews
Keyword(s):  
Membrane System ◽  
Growth Conditions ◽  
Rhodopseudomonas Capsulata ◽  
Phototrophic Growth ◽  
In Cells

NUTRIENT REQUIREMENTS AND GROWTH CONDITIONS FOR PRODUCTION OF LACTASE ENZYME BY SACCHAROMYCES FRAGILIS1

1970 ◽  
Vol 33 (10) ◽  
pp. 451-455 ◽  
Author(s):  
W. L. Wendorff ◽  
C. H. Amundson ◽  
N. F. Olson
Keyword(s):  
Growth Factors ◽  
Cheese Whey ◽  
Corn Steep Liquor ◽  
Growth Conditions ◽  
Nutrient Requirements ◽  
Lactase Activity ◽  
Optimum Conditions ◽  
Factors Affecting ◽  
Lactose Concentration ◽  
Steep Liquor

Lactase enzyme was produced by Saccharomyces fragilis NRRL Y-1109 grown in deproteinized Cheddar cheese whey. Nutrients and growth conditions required for maximum lactase production were determined. Lactose concentration, sources of growth factors; temperature of incubation, and pH of the whey were the primary factors affecting lactase production. Increased levels of lactose in whey stimulated the yeast to produce higher levels of lactase activity per gram of dried yeast. Corn steep liquor was the best source of added growth factors. Yeast grown under optimum conditions, pH 4.0 to 4.7 and 28 C, yielded 175 units per gram of yeast and 1300 units per liter of whey.

Alkalithermophiles

2004 ◽  
Vol 32 (2) ◽  
pp. 193-198 ◽  
Author(s):  
J. Wiegel ◽  
V.V. Kevbrin
Keyword(s):  
High Temperature ◽  
Environmental Parameters ◽  
Great Majority ◽  
Growth Conditions ◽  
Model Organisms ◽  
Extraterrestrial Life ◽  
Soils And Sediments ◽  
Alkaline Environments ◽  
Micro Organisms ◽  
Doubling Times

Alkalithermophiles are an exciting subset of extremophilic organisms and represent extremophiles that are adapted to two extreme conditions, i.e. to a combination of alkaline and thermobiotic growth conditions. Among the anaerobic alkalithermophiles are representatives of both Bacteria and Archaea within a wide variety of physiological types and systematic groups, although a great majority belongs to the Firmicutes. Alkaliphiles have been isolated from a variety of niches including mesobiotic and neutrophilic soils and sediments. Interestingly anaerobic isolates from mesobiotic and neutrophilic niches exhibit shorter doubling times than isolates from thermobiotic niches; some anaerobic alkalithermophiles exhibit extremely fast growth rates, i.e. doubling times as short as 10 min. Their adaptation to both high pH and high temperature draws our attention not only because they are potential sources of industrially valuable enzymes but also because of their adaptive mechanisms to external environmental parameters. They could thus function as model organisms for extraterrestrial life in some environments and for theories on the origin of life. Alkalithermophiles, as far we know, do not represent the most thermophilic nor the most alkaliphilic of micro-organisms but represent the most alkaliphilic ones among the thermophiles and vice versa. We believe that the presently known species are only the tip of the iceberg and therefore that they do not represent the true boundaries under which life can thrive in respect to high temperature in alkaline environments.

scholarly journals Integrated systems biology and imaging of the smallest free-living eukaryote Ostreococcus tauri

2018 ◽  
Author(s):  
Chuck R. Smallwood ◽  
Jian-Hua Chen ◽  
Neeraj Kumar ◽  
William Chrisler ◽  
Samuel O. Purvine ◽  
...  
Keyword(s):  
Biochemical Analysis ◽  
Starch Granule ◽  
Stimulated Raman Scattering ◽  
Nitrogen Depletion ◽  
Free Living ◽  
X Ray ◽  
Cellular Energy ◽  
Ostreococcus Tauri ◽  
Significant Expression ◽  
Long Chain

AbstractOstreococcus tauri is an ancient phototrophic microalgae that possesses favorable genetic and cellular characteristics for reductionist studies probing biosystem design and dynamics. Here multimodal bioimaging and multi-omics techniques were combined to interrogate O. tauri cellular changes in response to variations in bioavailable nitrogen and carbon ratios. Confocal microscopy, stimulated Raman scattering, and cryo-soft x-ray tomography revealed whole cell ultrastructural dynamics and composition while proteomic and lipidomic profiling captured changes at the molecular and macromolecular scale.Despite several energy dense long-chain triacylglycerol lipids showing more than 40-fold higher abundance under N deprivation, only a few proteins directly associated with lipid biogenesis showed significant expression changes. However, the entire pathway for starch granule biosynthesis was highly upregulated suggesting much of the cellular energy is preferentially directed towards starch over lipid accumulation. Additionally, three of the five most downregulated and five of the ten most upregulated proteins during severe nitrogen depletion were unnamed protein products that warrant additional biochemical analysis and functional annotation to control carbon transformation dynamics in this smallest eukaryote.

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