Genomic insights into metabolic versatility of a lithotrophic sulfur-oxidizing diazotrophic Alphaproteobacterium Azospirillum thiophilum.

PubMed

Orlova, Maria V; Tarlachkov, Sergey V; Dubinina, Galina A; Belousova, Elena V; Tutukina, Maria N; Grabovich, Margarita Y

2016-12-01

Diazotrophic Alphaproteobacteria of the genus Azospirillum are usually organotrophs, although some strains of Azospirillum lipoferum are capable of hydrogen-dependent autotrophic growth. Azospirillum thiophilum strain was isolated from a mineral sulfide spring, a biotope highly unusual for azospirilla. Here, the metabolic pathways utilized by A. thiophilum were revealed based on comprehensive analysis of its genomic organization, together with physiological and biochemical approaches. The A. thiophilum genome contained all the genes encoding the enzymes of carbon metabolism via glycolysis, tricarboxylic acid cycle and glyoxylate cycle. Genes for a complete set of enzymes responsible for autotrophic growth, with an active Calvin-Benson-Bassham cycle, were also revealed, and activity of the key enzymes was determined. Microaerobic chemolithoautotrophic growth of A. thiophilum was detected in the presence of thiosulfate and molecular hydrogen, being in line with the discovery of the genes encoding the two enzymes involved in dissimilatory thiosulfate oxidation, the Sox-complex and thiosulfate dehydrogenase and Ni-Fe hydrogenases. Azospirillum thiophilum utilizes methanol and formate, producing CO 2 that can further be metabolized via the Calvin cycle. Finally, it is capable of anaerobic respiration, using tetrathionate as a terminal electron acceptor. Such metabolic versatility is of great importance for adaptation of A. thiophilum to constantly changing physicochemical environment. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Respiration accumulates Calvin cycle intermediates for the rapid start of photosynthesis in Synechocystis sp. PCC 6803.

PubMed

Shimakawa, Ginga; Hasunuma, Tomohisa; Kondo, Akihiko; Matsuda, Mami; Makino, Amane; Miyake, Chikahiro

2014-01-01

We tested the hypothesis that inducing photosynthesis in cyanobacteria requires respiration. A mutant deficient in glycogen phosphorylase (∆GlgP) was prepared in Synechocystis sp. PCC 6803 to suppress respiration. The accumulated glycogen in ΔGlgP was 250-450% of that accumulated in wild type (WT). The rate of dark respiration in ΔGlgP was 25% of that in WT. In the dark, P700(+) reduction was suppressed in ΔGlgP, and the rate corresponded to that in (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone)-treated WT, supporting a lower respiration rate in ∆GlgP. Photosynthetic O2-evolution rate reached a steady-state value much slower in ∆GlgP than in WT. This retardation was solved by addition of d-glucose. Furthermore, we found that the contents of Calvin cycle intermediates in ∆GlgP were lower than those in WT under dark conditions. These observations indicated that respiration provided the carbon source for regeneration of ribulose 1,5-bisphosphate in order to drive the rapid start of photosynthesis.

Proteomic study participating the enhancement of growth and salt tolerance of bottle gourd rootstock-grafted watermelon seedlings.

PubMed

Yang, Yanjuan; Wang, Liping; Tian, Jing; Li, Jing; Sun, Jin; He, Lizhong; Guo, Shirong; Tezuka, Takafumi

2012-09-01

An insertion grafting technique to do research on salt tolerance was applied using watermelon (Citrullus lanatus [Thunb.] Mansf. cv. Xiuli) as a scion and bottle gourd (Lagenaria siceraria Standl. cv. Chaofeng Kangshengwang) as a rootstock. Rootstock-grafting significantly relieved the inhibition of growth and photosynthesis induced by salt stress in watermelon plants. Proteomic analysis revealed 40 different expressed proteins in response to rootstock-grafting and/or salt stress. These proteins were involved in Calvin cycle, amino acids biosynthesis, carbohydrate and energy metabolism, ROS defense, hormonal biosynthesis and signal transduction. Most of these proteins were up-regulated by rootstock-grafting and/or susceptible to salt stress. The enhancement of the metabolic activities of Calvin cycle, biosynthesis of amino acids, carotenoids and peroxisomes, glycolytic pathway and tricarboxylic acid cycle will probably contribute to intensify the biomass and photosynthetic capacity in rootstock-grafted seedlings under condition without salt. The accumulation of key enzymes included in these biological processes described above seems to play an important role in the enhancement of salt tolerance of rootstock-grafted seedlings. Furthermore, leucine-rich repeat transmembrane protein kinase and phospholipase may be involved in transmitting the internal and external stimuli induced by grafting and/or salt stress. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

An engineered Calvin-Benson-Bassham cycle for carbon dioxide fixation in Methylobacterium extorquens AM1.

PubMed

Schada von Borzyskowski, Lennart; Carrillo, Martina; Leupold, Simeon; Glatter, Timo; Kiefer, Patrick; Weishaupt, Ramon; Heinemann, Matthias; Erb, Tobias J

2018-04-04

Organisms are either heterotrophic or autotrophic, meaning that they cover their carbon requirements by assimilating organic compounds or by fixing inorganic carbon dioxide (CO 2 ). The conversion of a heterotrophic organism into an autotrophic one by metabolic engineering is a long-standing goal in synthetic biology and biotechnology, because it ultimately allows for the production of value-added compounds from CO 2 . The heterotrophic Alphaproteobacterium Methylobacterium extorquens AM1 is a platform organism for a future C1-based bioeconomy. Here we show that M. extorquens AM1 provides unique advantages for establishing synthetic autotrophy, because energy metabolism and biomass formation can be effectively separated from each other in the organism. We designed and realized an engineered strain of M. extorquens AM1 that can use the C1 compound methanol for energy acquisition and forms biomass from CO 2 by implementation of a heterologous Calvin-Benson-Bassham (CBB) cycle. We demonstrate that the heterologous CBB cycle is active, confers a distinct phenotype, and strongly increases viability of the engineered strain. Metabolic 13 C-tracer analysis demonstrates the functional operation of the heterologous CBB cycle in M. extorquens AM1 and comparative proteomics of the engineered strain show that the host cell reacts to the implementation of the CBB cycle in a plastic way. While the heterologous CBB cycle is not able to support full autotrophic growth of M. extorquens AM1, our study represents a further advancement in the design and realization of synthetic autotrophic organisms. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Melvin Calvin and Carbon in Photosynthesis

Science.gov Websites

Report Download Adobe PDF Reader , April 1950 Top Melvin Calvin and photosynthesis apparatus Courtesy Lawrence Berkeley National Laboratory Calvin in the old Radiation Laboratory with the apparatus used in his

Calvin Won't Sit Down! The Daily Behavior Report Card: A Practical Technique to Change Student Behavior and Increase School-Home Communication

ERIC Educational Resources Information Center

Mires, Carolyn B.; Lee, David L.

2017-01-01

Calvin is a student who will not stay in his seat. He calls out constantly. Calvin does not complete his class work, and his homework is rarely returned. Do you have a student like Calvin? Does he fail to turn in homework, or act disrespectfully toward teachers and peers? Easy to implement, the Daily Behavior Report Card is an empirically based…

Changes in SBPase activity influence photosynthetic capacity, growth, and tolerance to chilling stress in transgenic tomato plants

PubMed Central

Ding, Fei; Wang, Meiling; Zhang, Shuoxin; Ai, Xizhen

2016-01-01

Sedoheptulose-1, 7-bisphosphatase (SBPase) is an important enzyme involved in photosynthetic carbon fixation in the Calvin cycle. Here, we report the impact of changes in SBPase activity on photosynthesis, growth and development, and chilling tolerance in SBPase antisense and sense transgenic tomato (Solanum lycopersicum) plants. In transgenic plants with increased SBPase activity, photosynthetic rates were increased and in parallel an increase in sucrose and starch accumulation was evident. Total biomass and leaf area were increased in SBPase sense plants, while they were reduced in SBPase antisense plants compared with equivalent wild-type tomato plants. Under chilling stress, when compared with plants with decreased SBPase activity, tomato plants with increased SBPase activity were found to be more chilling tolerant as indicated by reduced electrolyte leakage, increased photosynthetic capacity, and elevated RuBP regeneration rate and quantum efficiency of photosystem II. Collectively, our data suggest that higher level of SBPase activity gives an advantage to photosynthesis, growth and chilling tolerance in tomato plants. This work also provides a case study that an individual enzyme in the Calvin cycle may serve as a useful target for genetic engineering to improve production and stress tolerance in crops. PMID:27586456

Photosynthetic carbon fixation characteristics of fruiting structures of Brassica campestris L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singal, H.R.; Sheoran, I.S.; Singh, R.

1987-04-01

Activities of key enzymes of the Calvin cycle and C/sub 4/ metabolism, rates of CO/sub 2/ fixation, and the initial products of photosynthetic /sup 14/CO/sub 2/ fixation were determined in the podwall, seed coat (fruiting structures), and the subtending leaf (leaf below a receme) of Brassica campestris L. cv Toria. Compared to activities of ribulose-1,5-bisphosphate carboxylase and other Calvin cycle enzymes, e.g. NADP-glyceraldehyde-3-phosphate-dehydrogenase and ribulose-5-phosphate kinase, the activities of phosphoenol pyruvate carboxylase and other enzymes of C/sub 4/ metabolism, viz. NADP-malate dehydrogenase, NADP-malic enzyme, glutamate pyruvate transaminase, and glutamate oxaloacetate transaminase, were generally much higher in seed than in podwallmore » and leaf. Podwall and leaf were comparable to each other. Pulse-chase experiments showed that in seed the major product of /sup 14/CO/sub 2/ assimilation was malate (in short time), whereas in podwall and leaf, the label initially appeared in 3-PGA. With time, the label moved to sucrose. In contrast to legumes, Brassica pods were able to fix net CO/sub 2/ during light. However, respiratory losses were very high during the dark period.« less

The Calvin impact crater and its associated oil production, Cass County, Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milstein, R.L.

1996-01-01

The Calvin impact crater is an isolated, nearly circular subsurface structure of Late Ordovician age in southwestern Michigan. The crater is defined by 110 oil and gas test wells, has a diameter of 6.2 km, and consists of a central dome exhibiting 415 m of structural uplift, an annular depression, and an encircling anticlinal rim. Exploration and development of three Devonian oil fields associated wit this structure provide all available subsurface data. All oil production is from the Middle Devonian Traverse Limestone, with the exception of one well producing from the Middle Devonian Sylvania Sandstone. This study models the grossmore » morphology of the Calvin structure using multiple tools and compares the results to known impact craters. Combined results of reflection seismic, gravity, magnetic, and resistivity data, as well as organized relationships between stratigraphic displacement and structural diameters observed in complex impact craters, suggest the Calvin structure is morphologically similar to recognized complex impact craters in sedimentary targets. In addition, individual quartz grains recovered from the Calvin structure exhibit decorated shock lamellae, Boehm lamellae, rhombohederal cleavage, and radiating concussion fractures. Based on the available data, I conclude the Calvin structure is a buried complex impact crater and that the trapping and reservoir characteristics of the associated Calvin 20, Juno Lake, and Calvin 28 oil fields are resultant of the craters morphology.« less

The Calvin impact crater and its associated oil production, Cass County, Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milstein, R.L.

1996-12-31

The Calvin impact crater is an isolated, nearly circular subsurface structure of Late Ordovician age in southwestern Michigan. The crater is defined by 110 oil and gas test wells, has a diameter of 6.2 km, and consists of a central dome exhibiting 415 m of structural uplift, an annular depression, and an encircling anticlinal rim. Exploration and development of three Devonian oil fields associated wit this structure provide all available subsurface data. All oil production is from the Middle Devonian Traverse Limestone, with the exception of one well producing from the Middle Devonian Sylvania Sandstone. This study models the grossmore » morphology of the Calvin structure using multiple tools and compares the results to known impact craters. Combined results of reflection seismic, gravity, magnetic, and resistivity data, as well as organized relationships between stratigraphic displacement and structural diameters observed in complex impact craters, suggest the Calvin structure is morphologically similar to recognized complex impact craters in sedimentary targets. In addition, individual quartz grains recovered from the Calvin structure exhibit decorated shock lamellae, Boehm lamellae, rhombohederal cleavage, and radiating concussion fractures. Based on the available data, I conclude the Calvin structure is a buried complex impact crater and that the trapping and reservoir characteristics of the associated Calvin 20, Juno Lake, and Calvin 28 oil fields are resultant of the craters morphology.« less

Systems-Wide Analysis of Acclimation Responses to Long-Term Heat Stress and Recovery in the Photosynthetic Model Organism Chlamydomonas reinhardtii[W][OPEN

PubMed Central

Hemme, Dorothea; Veyel, Daniel; Mühlhaus, Timo; Sommer, Frederik; Jüppner, Jessica; Unger, Ann-Katrin; Sandmann, Michael; Fehrle, Ines; Schönfelder, Stephanie; Steup, Martin; Geimer, Stefan; Kopka, Joachim; Giavalisco, Patrick; Schroda, Michael

2014-01-01

We applied a top-down systems biology approach to understand how Chlamydomonas reinhardtii acclimates to long-term heat stress (HS) and recovers from it. For this, we shifted cells from 25 to 42°C for 24 h and back to 25°C for ≥8 h and monitored abundances of 1856 proteins/protein groups, 99 polar and 185 lipophilic metabolites, and cytological and photosynthesis parameters. Our data indicate that acclimation of Chlamydomonas to long-term HS consists of a temporally ordered, orchestrated implementation of response elements at various system levels. These comprise (1) cell cycle arrest; (2) catabolism of larger molecules to generate compounds with roles in stress protection; (3) accumulation of molecular chaperones to restore protein homeostasis together with compatible solutes; (4) redirection of photosynthetic energy and reducing power from the Calvin cycle to the de novo synthesis of saturated fatty acids to replace polyunsaturated ones in membrane lipids, which are deposited in lipid bodies; and (5) when sinks for photosynthetic energy and reducing power are depleted, resumption of Calvin cycle activity associated with increased photorespiration, accumulation of reactive oxygen species scavengers, and throttling of linear electron flow by antenna uncoupling. During recovery from HS, cells appear to focus on processes allowing rapid resumption of growth rather than restoring pre-HS conditions. PMID:25415976

Nitrate and Ammonium Induced Photosynthetic Suppression in N-Limited Selenastrum minutum.

PubMed

Elrifi, I R; Turpin, D H

1986-05-01

Nitrate-limited chemostat cultures of Selenastrum minutum Naeg. Collins (Chlorophyta) were used to determine the effects of nitrogen addition on photosynthesis, dark respiration, and dark carbon fixation. Addition of NO(3) (-) or NH(4) (+) induced a transient suppression of photosynthetic carbon fixation (70 and 40% respectively). Intracellular ribulose bisphosphate levels decreased during suppression and recovered in parallel with photosynthesis. Photosynthetic oxygen evolution was decreased by N-pulsing under saturating light (650 microeinsteins per square meter per second). Under subsaturating light intensities (<165 microeinsteins per square meter per second) NH(4) (+) addition resulted in O(2) consumption in the light which was alleviated by the presence of the tricarboxylic acid cycle inhibitor fluoroacetate. Addition of NO(3) (-) or NH(4) (+) resulted in a large stimulation of dark respiration (67 and 129%, respectively) and dark carbon fixation (360 and 2080%, respectively). The duration of N-induced perturbations was dependent on the concentration of added N. Inhibition of glutamine 2-oxoglutarate aminotransferase by azaserine alleviated all these effects. It is proposed that suppression of photosynthetic carbon fixation in response to N pulsing was the result of a competition for metabolites between the Calvin cycle and nitrogen assimilation. Carbon skeletons required for nitrogen assimilation would be derived from tricarboxylic acid cycle intermediates. To maintain tricarboxylic acid cycle activity triose phosphates would be exported from the chloroplast. This would decrease the rate of ribulose bisphosphate regeneration and consequently decrease net photosynthetic carbon accumulation. Stoichiometric calculations indicate that the Calvin cycle is one source of triose phosphates for N assimilation; however, during transient N resupply the major demand for triose phosphates must be met by starch or sucrose breakdown. The effects of N-pulsing on O(2) evolution, dark respiration, and dark C-fixation are shown to be consistent with this model.

76 FR 20034 - Calvin Ramsey, M.D.; Revocation of Registration

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

... DEPARTMENT OF JUSTICE Drug Enforcement Administration [Docket No. 10-25] Calvin Ramsey, M.D... Control, Drug Enforcement Administration, issued an Order to Show Cause to Calvin Ramsey, M.D. (Respondent.... Respondent's Resp., at 1. Therein, Respondent asserted that ``[d]ue process dictates that this Court must...

Path of carbon flow during NO/sub 3//sup -/-induced photosynthetic suppression in N-limited Selenastrum minutum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elrifi, I.R.; Turpin, D.H.

Nitrate addition to nitrate-limited cultures of Selenastrum minutum Naeg. Collins (Chlorophyta) resulted in a 70% suppression of photosynthetic carbon fixation. In /sup 14/CO/sub 2/ pulse/chase experiments nitrate resupply increased radiolabel incorporation into amino and organic acids and decreased radiolabel incorporation into insoluble material. Nitrate resupply increased the concentration of phosphoenolpyruvate and increased the radiolabeling of phosphoenolpyruvate, pyruvate and tricarboxylic acid cycle intermediates, notably citrate, fumarate, and malate. Furthermore, nitrate also increased the pool sizes and radiolabeling of most amino acids, with alanine, aspartate, glutamate, and glutamine showing the largest changes. Nitrate resupply increased the proportion of radiolabel in the C-4more » position of malate and increased the ratios of radiolabel in aspartate to phosphoenolpyruvate and in pyruvate to phosphoenolpyruvate, indicative of increased phosphoenolpyruvate carboxylase and pyruvate kinase activities. Analysis of these data showed that the rate of carbon flow through glutamate (10.6 ..mu..moles glutamate per milligram chlorophyll per hour) and the rate of net glutamate production (7.9 ..mu..moles glutamate per milligram chlorophyll per hour) were both greater than the maximum rate of carbon export from the Calvin cycle which could be maintained during steady state photosynthesis. These results are consistent with the hypothesis that nitrogen resupply to nitrogen-limited microalgae results in a transient suppression of photosynthetic carbon fixation due, in part, to the severity of competition for carbon skeletons between the Calvin cycle and nitrogen assimilation.« less

The Path of Carbon Flow during NO3−-Induced Photosynthetic Suppression in N-Limited Selenastrum minutum1

PubMed Central

Elrifi, Ivor R.; Turpin, David H.

1987-01-01

Nitrate addition to nitrate-limited cultures of Selenastrum minutum Naeg. Collins (Chlorophyta) resulted in a 70% suppression of photosynthetic carbon fixation. In 14CO2 pulse/chase experiments nitrate resupply increased radiolabel incorporation into amino and organic acids and decreased radiolabel incorporation into insoluble material. Nitrate resupply increased the concentration of phosphoenolpyruvate and increased the radiolabeling of phosphoenolpyruvate, pyruvate and tricarboxylic acid cycle intermediates, notably citrate, fumarate, and malate. Furthermore, nitrate also increased the pool sizes and radiolabeling of most amino acids, with alanine, aspartate, glutamate, and glutamine showing the largest changes. Nitrate resupply increased the proportion of radiolabel in the C-4 position of malate and increased the ratios of radiolabel in aspartate to phosphoenolpyruvate and in pyruvate to phosphoenolpyruvate, indicative of increased phosphoenolpyruvate carboxylase and pyruvate kinase activities. Analysis of these data showed that the rate of carbon flow through glutamate (10.6 μmoles glutamate per milligram chlorophyll per hour) and the rate of net glutamate production (7.9 μmoles glutamate per milligram chlorophyll per hour) were both greater than the maximum rate of carbon export from the Calvin cycle which could be maintained during steady state photosynthesis. These results are consistent with the hypothesis that nitrogen resupply to nitrogen-limited microalgae results in a transient suppression of photosynthetic carbon fixation due, in part, to the severity of competition for carbon skeletons between the Calvin cycle and nitrogen assimilation (IR Elrifi, DH Turpin 1986 Plant Physiol 81: 273-279). PMID:16665223

The Path of Carbon Flow during NO(3)-Induced Photosynthetic Suppression in N-Limited Selenastrum minutum.

PubMed

Elrifi, I R; Turpin, D H

1987-01-01

Nitrate addition to nitrate-limited cultures of Selenastrum minutum Naeg. Collins (Chlorophyta) resulted in a 70% suppression of photosynthetic carbon fixation. In (14)CO(2) pulse/chase experiments nitrate resupply increased radiolabel incorporation into amino and organic acids and decreased radiolabel incorporation into insoluble material. Nitrate resupply increased the concentration of phosphoenolpyruvate and increased the radiolabeling of phosphoenolpyruvate, pyruvate and tricarboxylic acid cycle intermediates, notably citrate, fumarate, and malate. Furthermore, nitrate also increased the pool sizes and radiolabeling of most amino acids, with alanine, aspartate, glutamate, and glutamine showing the largest changes. Nitrate resupply increased the proportion of radiolabel in the C-4 position of malate and increased the ratios of radiolabel in aspartate to phosphoenolpyruvate and in pyruvate to phosphoenolpyruvate, indicative of increased phosphoenolpyruvate carboxylase and pyruvate kinase activities. Analysis of these data showed that the rate of carbon flow through glutamate (10.6 mumoles glutamate per milligram chlorophyll per hour) and the rate of net glutamate production (7.9 mumoles glutamate per milligram chlorophyll per hour) were both greater than the maximum rate of carbon export from the Calvin cycle which could be maintained during steady state photosynthesis. These results are consistent with the hypothesis that nitrogen resupply to nitrogen-limited microalgae results in a transient suppression of photosynthetic carbon fixation due, in part, to the severity of competition for carbon skeletons between the Calvin cycle and nitrogen assimilation (IR Elrifi, DH Turpin 1986 Plant Physiol 81: 273-279).

Functional Differentiation of Bundle Sheath and Mesophyll Maize Chloroplasts Determined by Comparative ProteomicsW⃞

PubMed Central

Majeran, Wojciech; Cai, Yang; Sun, Qi; van Wijk, Klaas J.

2005-01-01

Chloroplasts of maize (Zea mays) leaves differentiate into specific bundle sheath (BS) and mesophyll (M) types to accommodate C4 photosynthesis. Consequences for other plastid functions are not well understood but are addressed here through a quantitative comparative proteome analysis of purified M and BS chloroplast stroma. Three independent techniques were used, including cleavable stable isotope coded affinity tags. Enzymes involved in lipid biosynthesis, nitrogen import, and tetrapyrrole and isoprenoid biosynthesis are preferentially located in the M chloroplasts. By contrast, enzymes involved in starch synthesis and sulfur import preferentially accumulate in BS chloroplasts. The different soluble antioxidative systems, in particular peroxiredoxins, accumulate at higher levels in M chloroplasts. We also observed differential accumulation of proteins involved in expression of plastid-encoded proteins (e.g., EF-Tu, EF-G, and mRNA binding proteins) and thylakoid formation (VIPP1), whereas others were equally distributed. Enzymes related to the C4 shuttle, the carboxylation and regeneration phase of the Calvin cycle, and several regulators (e.g., CP12) distributed as expected. However, enzymes involved in triose phosphate reduction and triose phosphate isomerase are primarily located in the M chloroplasts, indicating that the M-localized triose phosphate shuttle should be viewed as part of the BS-localized Calvin cycle, rather than a parallel pathway. PMID:16243905

Proteome Analyses of Strains ATCC 51142 and PCC 7822 of the Diazotrophic Cyanobacterium Cyanothece sp under Culture Conditions Resulting in Enhanced H-2 Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aryal, Uma K.; Callister, Stephen J.; Mishra, Sujata

2013-02-01

Cultures of the cyanobacterial genus Cyanothece have been shown to produce high levels of biohydrogen. These strains are diazotrophic and undergo pronounced diurnal cycles when grown under N2-fixing conditions in light-dark cycles. We seek to better understand the way in which proteins respond to these diurnal changes and we performed quantitative proteome analysis of Cyanothece ATCC 51142 and PCC 7822 grown under 8 different nutritional conditions. Nitrogenase expression was limited to N2-fixing conditions, and in the absence of glycerol, nitrogenase gene expression was linked to the dark period. However, glycerol induced expression of nitrogenase during part of the light period,more » together with cytochrome c oxidase (Cox), glycogen phosphorylase (Glp), and glycolytic and pentose-phosphate pathway (PPP) enzymes. This indicated that nitrogenase expression in the light was facilitated via higher respiration and glycogen breakdown. Key enzymes of the Calvin cycle were inhibited in Cyanothece ATCC 51142 in the presence of glycerol under H2 producing conditions, suggesting a competition between these sources of carbon. However, in Cyanothece PCC 7822, the Calvin cycle still played a role in cofactor recycling during H2 production. Our data comprise the first comprehensive profiling of proteome changes in Cyanothece PCC 7822, and allows an in-depth comparative analysis of major physiological and biochemical processes that influence H2-production in both the strains. Our results revealed many previously uncharacterized proteins that may play a role in nitrogenase activity and in other metabolic pathways and may provide suitable targets for genetic manipulation that would lead to improvement of large scale H2 production.« less

Global CO2 Levels and the Calvin Cycle

DTIC Science & Technology

1990-01-01

metabolic responsibilities. .’ There is no question that Rubisco has received much attention by investigators (e.g. Newman and Cattolico, 1990; Glover... Rubisco 3 PGA - 14C ATP ADP 14C02 in which 14CO2 incorporation into phosphoglyceric acid is measured (Marsden and Codd, 1984). Fractions containing...a latent, large molecular weight enzyme that is seen in the fresh water alga Scenedesmus. Helerosigma PRK is well separated from its Rubisco (mwt

Calvin Beale's Legacy for Rural Demography

ERIC Educational Resources Information Center

Brown, David L.; Elo, Irma T.

2011-01-01

Calvin Lunsford Beale was born in Washington, DC, on June 6, 1923, and passed away at age 85 on September 2, 2008. He was a city boy born and bred, and while he "never wanted to live in a rural area" he became one of the most astute observers of rural America in the latter half of the twentieth century. Calvin spent the majority of his…

Validation Test Report For The CRWMS Analysis and Logistics Visually Interactive Model Calvin Version 3.0, 10074-Vtr-3.0-00

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. Gillespie

2000-07-27

This report describes the tests performed to validate the CRWMS ''Analysis and Logistics Visually Interactive'' Model (CALVIN) Version 3.0 (V3.0) computer code (STN: 10074-3.0-00). To validate the code, a series of test cases was developed in the CALVIN V3.0 Validation Test Plan (CRWMS M&O 1999a) that exercises the principal calculation models and options of CALVIN V3.0. Twenty-five test cases were developed: 18 logistics test cases and 7 cost test cases. These cases test the features of CALVIN in a sequential manner, so that the validation of each test case is used to demonstrate the accuracy of the input to subsequentmore » calculations. Where necessary, the test cases utilize reduced-size data tables to make the hand calculations used to verify the results more tractable, while still adequately testing the code's capabilities. Acceptance criteria, were established for the logistics and cost test cases in the Validation Test Plan (CRWMS M&O 1999a). The Logistics test cases were developed to test the following CALVIN calculation models: Spent nuclear fuel (SNF) and reactivity calculations; Options for altering reactor life; Adjustment of commercial SNF (CSNF) acceptance rates for fiscal year calculations and mid-year acceptance start; Fuel selection, transportation cask loading, and shipping to the Monitored Geologic Repository (MGR); Transportation cask shipping to and storage at an Interim Storage Facility (ISF); Reactor pool allocation options; and Disposal options at the MGR. Two types of cost test cases were developed: cases to validate the detailed transportation costs, and cases to validate the costs associated with the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M&O) and Regional Servicing Contractors (RSCs). For each test case, values calculated using Microsoft Excel 97 worksheets were compared to CALVIN V3.0 scenarios with the same input data and assumptions. All of the test case results compare with the CALVIN V3.0 results within the bounds of the acceptance criteria. Therefore, it is concluded that the CALVIN V3.0 calculation models and options tested in this report are validated.« less

The drug ornidazole inhibits photosynthesis in a different mechanism described for protozoa and anaerobic bacteria.

PubMed

Marcus, Yehouda; Tal, Noam; Ronen, Mordechai; Carmieli, Raanan; Gurevitz, Michael

2016-12-01

Ornidazole of the 5-nitroimidazole drug family is used to treat protozoan and anaerobic bacterial infections via a mechanism that involves preactivation by reduction of the nitro group, and production of toxic derivatives and radicals. Metronidazole, another drug family member, has been suggested to affect photosynthesis by draining electrons from the electron carrier ferredoxin, thus inhibiting NADP + reduction and stimulating radical and peroxide production. Here we show, however, that ornidazole inhibits photosynthesis via a different mechanism. While having a minute effect on the photosynthetic electron transport and oxygen photoreduction, ornidazole hinders the activity of two Calvin cycle enzymes, triose-phosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Modeling of ornidazole's interaction with ferredoxin of the protozoan Trichomonas suggests efficient electron tunneling from the iron-sulfur cluster to the nitro group of the drug. A similar docking site of ornidazole at the plant-type ferredoxin does not exist, and the best simulated alternative does not support such efficient tunneling. Notably, TPI was inhibited by ornidazole in the dark or when electron transport was blocked by dichloromethyl diphenylurea, indicating that this inhibition was unrelated to the electron transport machinery. Although TPI and GAPDH isoenzymes are involved in glycolysis and gluconeogenesis, ornidazole's effect on respiration of photoautotrophs is moderate, thus raising its value as an efficient inhibitor of photosynthesis. The scarcity of Calvin cycle inhibitors capable of penetrating cell membranes emphasizes on the value of ornidazole for studying the regulation of this cycle. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Characteristics of plastids responsible for starch synthesis in developing pea embryos.

PubMed

Smith, A M; Quinton-Tulloch, J; Denyer, K

1990-03-01

The nature of the starch-synthesising plastids in developing pea (Pisum sativum L.) embryos has been investigated. Chlorophyll and starch were distributed throughout the cotyledon during development. Chlorophyll content increased initially, then showed little change up to the point of drying out of the embryo. Starch content per embryo increased dramatically throughout development. The chlorophyll content per unit volume was highest on the outer edge of the cotyledon, while the starch content was highest on inner face. Nycodenz gradients, which fractionated mechanically-prepared plastids according to their starch content, failed to achieve any significant separation of plastids rich in starch and ADP-glucose pyrophosphorylase from those rich in chlorophyll and a Calvin-cycle marker enzyme, NADP-glyceraldehyde-3-phosphate dehydrogenase. However, material that was not sufficiently dense to enter the gradients was enriched in activity of the Calvin-cycle marker enzyme relative to that of ADP-glucose pyrophosphorylase. Nomarski and epi-fluorescence microscopy showed that intact, isolated plastids, including those with very large starch grains, invariably contained chlorophyll in stromal structures peripheral to the starch grain. We suggest that the starch-storing plastids of developing pea embryos are derived directly from chloroplasts, and retain chloroplast-like characteristics throughout their development. Developing pea embryos also contain chloroplasts which store little or no starch. These are probably located primarily on the outer edge of the cotyledons where there is sufficient light for photosynthesis at some stages of development.

Nitrate and Ammonium Induced Photosynthetic Suppression in N-Limited Selenastrum minutum1

PubMed Central

Elrifi, Ivor R.; Turpin, David H.

1986-01-01

Nitrate-limited chemostat cultures of Selenastrum minutum Naeg. Collins (Chlorophyta) were used to determine the effects of nitrogen addition on photosynthesis, dark respiration, and dark carbon fixation. Addition of NO3− or NH4+ induced a transient suppression of photosynthetic carbon fixation (70 and 40% respectively). Intracellular ribulose bisphosphate levels decreased during suppression and recovered in parallel with photosynthesis. Photosynthetic oxygen evolution was decreased by N-pulsing under saturating light (650 microeinsteins per square meter per second). Under subsaturating light intensities (<165 microeinsteins per square meter per second) NH4+ addition resulted in O2 consumption in the light which was alleviated by the presence of the tricarboxylic acid cycle inhibitor fluoroacetate. Addition of NO3− or NH4+ resulted in a large stimulation of dark respiration (67 and 129%, respectively) and dark carbon fixation (360 and 2080%, respectively). The duration of N-induced perturbations was dependent on the concentration of added N. Inhibition of glutamine 2-oxoglutarate aminotransferase by azaserine alleviated all these effects. It is proposed that suppression of photosynthetic carbon fixation in response to N pulsing was the result of a competition for metabolites between the Calvin cycle and nitrogen assimilation. Carbon skeletons required for nitrogen assimilation would be derived from tricarboxylic acid cycle intermediates. To maintain tricarboxylic acid cycle activity triose phosphates would be exported from the chloroplast. This would decrease the rate of ribulose bisphosphate regeneration and consequently decrease net photosynthetic carbon accumulation. Stoichiometric calculations indicate that the Calvin cycle is one source of triose phosphates for N assimilation; however, during transient N resupply the major demand for triose phosphates must be met by starch or sucrose breakdown. The effects of N-pulsing on O2 evolution, dark respiration, and dark C-fixation are shown to be consistent with this model. PMID:16664788

Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

PubMed

Santos, Bruna Marques Dos; Balbuena, Tiago Santana

2017-01-06

Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO 2 concentrations. Growth under a high concentration of CO 2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO 2 . Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO 2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO 2 . Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO 2 -enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO 2 -enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO 2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in carbon assimilation may be used in plant transformation strategies aiming to increase plant adaptability to climate changes or to increase plant productivity. Copyright © 2016 Elsevier B.V. All rights reserved.

9. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 SECTION, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

Metabolite pools and carbon flow during C4 photosynthesis in maize: 13CO2 labeling kinetics and cell type fractionation.

PubMed

Arrivault, Stéphanie; Obata, Toshihiro; Szecówka, Marek; Mengin, Virginie; Guenther, Manuela; Hoehne, Melanie; Fernie, Alisdair R; Stitt, Mark

2017-01-01

Worldwide efforts to engineer C 4 photosynthesis into C 3 crops require a deep understanding of how this complex pathway operates. CO 2 is incorporated into four-carbon metabolites in the mesophyll, which move to the bundle sheath where they are decarboxylated to concentrate CO 2 around RuBisCO. We performed dynamic 13 CO 2 labeling in maize to analyze C flow in C 4 photosynthesis. The overall labeling kinetics reflected the topology of C 4 photosynthesis. Analyses of cell-specific labeling patterns after fractionation to enrich bundle sheath and mesophyll cells revealed concentration gradients to drive intercellular diffusion of malate, but not pyruvate, in the major CO 2 -concentrating shuttle. They also revealed intercellular concentration gradients of aspartate, alanine, and phosphenolpyruvate to drive a second phosphoenolpyruvate carboxykinase (PEPCK)-type shuttle, which carries 10-14% of the carbon into the bundle sheath. Gradients also exist to drive intercellular exchange of 3-phosphoglycerate and triose-phosphate. There is rapid carbon exchange between the Calvin-Benson cycle and the CO 2 -concentrating shuttle, equivalent to ~10% of carbon gain. In contrast, very little C leaks from the large pools of metabolites in the C concentration shuttle into respiratory metabolism. We postulate that the presence of multiple shuttles, alongside carbon transfer between them and the Calvin-Benson cycle, confers great flexibility in C 4 photosynthesis. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Genome-wide analysis of the fructose 1,6-bisphosphate aldolase (FBA) gene family and functional characterization of FBA7 in tomato.

PubMed

Cai, Bingbing; Li, Qiang; Xu, Yongchao; Yang, Long; Bi, Huangai; Ai, Xizhen

2016-11-01

Fructose 1,6-bisphosphate aldolase (FBA) is a key enzyme in plants that is involved in glycolysis, gluconeogenesis, and the Calvin cycle. FBA genes play significant roles in biotic and abiotic stress responses and also regulate growth and development. Despite the importance of FBA genes, little is known about it in tomato. In this study, we identified 8 FBA genes in tomato and classified them into 2 subgroups based on a phylogenetic tree, gene structures, and conserved motifs. Five (SlFBA1, 2, 3, 4 and 5) and three (SlFBA6, 7, and 8) SlFBA proteins were predicted to be localized in chloroplasts and cytoplasm, respectively. The phylogenetic analysis of FBAs from tomato, Arabidopsis, rice, and other organisms suggested that SlFBA shared the highest protein homology with FBAs from other plants. Synteny analysis indicated that segmental duplication events contributed to the expansion of the tomato FBA family. The expression profiles revealed that all SlFBAs were involved in the response to low and high temperature stresses. SlFBA7 overexpression increased the expression and activities of other main enzymes in Calvin cycle, net photosynthetic rate (Pn), seed size and stem diameter. SlFBA7 overexpression enhanced tolerances in seed germination under suboptimal temperature stresses. Taken together, comprehensive analyses of SlFBAs would provide a basis for understanding of evolution and function of SlFBA family. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

2. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 BASEMENT PLAN, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

3. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 FIRST FLOOR PLAN, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

7. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 WEST ELEVATION, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

5. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 ATTIC PLAN, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

6. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 EAST ELEVATION, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

4. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 SECOND FLOOR PLAN, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

8. Historic American Buildings Survey Photocopy of drawing in office ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Historic American Buildings Survey Photocopy of drawing in office of John Calvin Stevens, 127 Prospect Street, Portland, Maine 04101 NORTH AND SOUTH ELEVATIONS, 1905 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

11. Historic American Buildings Survey Photocopy of illustration in The ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Historic American Buildings Survey Photocopy of illustration in The American Architect and Buildings News, Vol. XVI, No. 469, December 20, 1884 PERSPECTIVE BY JOHN CALVIN STEVENS - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

History of Higher Education Annual, 1985.

ERIC Educational Resources Information Center

Karp, Alan; And Others

1985-01-01

This volume of the History of Higher Education Annual contains five articles. Alan Karp's essay, "John Calvin and the Geneva Academy: Roots of the Board of Trustees," discusses the reoganization and government of the Geneva Academy and Calvin's unsuccessful struggle to establish a church independent of lay control. Institutional…

Modulations in primary and secondary metabolic pathways and adjustment in physiological behaviour of Withania somnifera under drought stress.

PubMed

Singh, Ruchi; Gupta, Pankhuri; Khan, Furqan; Singh, Susheel Kumar; Sanchita; Mishra, Tripti; Kumar, Anil; Dhawan, Sunita Singh; Shirke, Pramod Arvind

2018-07-01

In general medicinal plants grown under water limiting conditions show much higher concentrations of secondary metabolites in comparison to control plants. In the present study, Withania somnifera plants were subjected to water stress and data related to drought tolerance phenomenon was collected and a putative mechanistic concept considering growth responses, physiological behaviour, and metabolite content and gene expression aspects is presented. Drought induced metabolic and physiological responses as well as drastic decrease in CO 2 uptake due to stomatal limitations. As a result, the consumption of reduction equivalents (NADPH 2+ ) for CO 2 assimilation via the calvin cycle declines significantly resulting in the generation of a large oxidative stress and an oversupply of antioxidant enzymes. Drought also results in the shifting of metabolic processes towards biosynthetic activities that consume reduction equivalents. Thus, biosynthesis of reduced compounds (isoprenoids, phenols and alkaloids) is enhanced. The dynamics of various metabolites have been discussed in the light of gene expression analysis of control and drought treated leaves. Gene encoding enzymes of pathways leading to glucose, fructose and fructan production, conversion of triose phosphates to hexoses and hexose phosphorylation were up-regulated in the drought stressed leaves. The down-regulated Calvin cycle genes were co-ordinately regulated with the down-regulation of chloroplast triosephosphate/phosphate translocator, cytoplasmic fructose-1,6-bisphosphate aldolase and fructose bisphosphatase. Expression of gene encoding Squalene Synthase (SQS) was highly upregulated under drought stress which is responsible for the diversion of carbon flux towards withanolides biosynthesis from isoprenoid pathway. Copyright © 2018 Elsevier B.V. All rights reserved.

In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop.

PubMed

Shivhare, Devendra; Mueller-Cajar, Oliver

2017-07-01

To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice ( Oryza sativa ) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. © 2017 American Society of Plant Biologists. All Rights Reserved.

In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop1[OPEN

PubMed Central

Shivhare, Devendra

2017-01-01

To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice (Oryza sativa) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca. Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. PMID:28546437

Thioredoxin f1 and NADPH-Dependent Thioredoxin Reductase C Have Overlapping Functions in Regulating Photosynthetic Metabolism and Plant Growth in Response to Varying Light Conditions.

PubMed

Thormählen, Ina; Meitzel, Tobias; Groysman, Julia; Öchsner, Alexandra Bianca; von Roepenack-Lahaye, Edda; Naranjo, Belén; Cejudo, Francisco J; Geigenberger, Peter

2015-11-01

Two different thiol redox systems exist in plant chloroplasts, the ferredoxin-thioredoxin (Trx) system, which depends on ferredoxin reduced by the photosynthetic electron transport chain and, thus, on light, and the NADPH-dependent Trx reductase C (NTRC) system, which relies on NADPH and thus may be linked to sugar metabolism in the dark. Previous studies suggested, therefore, that the two different systems may have different functions in plants. We now report that there is a previously unrecognized functional redundancy of Trx f1 and NTRC in regulating photosynthetic metabolism and growth. In Arabidopsis (Arabidopsis thaliana) mutants, combined, but not single, deficiencies of Trx f1 and NTRC led to severe growth inhibition and perturbed light acclimation, accompanied by strong impairments of Calvin-Benson cycle activity and starch accumulation. Light activation of key enzymes of these pathways, fructose-1,6-bisphosphatase and ADP-glucose pyrophosphorylase, was almost completely abolished. The subsequent increase in NADPH-NADP(+) and ATP-ADP ratios led to increased nitrogen assimilation, NADP-malate dehydrogenase activation, and light vulnerability of photosystem I core proteins. In an additional approach, reporter studies show that Trx f1 and NTRC proteins are both colocalized in the same chloroplast substructure. Results provide genetic evidence that light- and NADPH-dependent thiol redox systems interact at the level of Trx f1 and NTRC to coordinately participate in the regulation of the Calvin-Benson cycle, starch metabolism, and growth in response to varying light conditions. © 2015 American Society of Plant Biologists. All Rights Reserved.

Inter-species variation in the oligomeric states of the higher plant Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase and phosphoribulokinase

PubMed Central

Lloyd, Julie C.; Raines, Christine A.

2011-01-01

In darkened leaves the Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) form a regulatory multi-enzyme complex with the small chloroplast protein CP12. GAPDH also forms a high molecular weight regulatory mono-enzyme complex. Given that there are different reports as to the number and subunit composition of these complexes and that enzyme regulatory mechanisms are known to vary between species, it was reasoned that protein–protein interactions may also vary between species. Here, this variation is investigated. This study shows that two different tetramers of GAPDH (an A2B2 heterotetramer and an A4 homotetramer) have the capacity to form part of the PRK/GAPDH/CP12 complex. The role of the PRK/GAPDH/CP12 complex is not simply to regulate the ‘non-regulatory’ A4 GAPDH tetramer. This study also demonstrates that the abundance and nature of PRK/GAPDH/CP12 interactions are not equal in all species and that whilst NAD enhances complex formation in some species, this is not sufficient for complex formation in others. Furthermore, it is shown that the GAPDH mono-enzyme complex is more abundant as a 2(A2B2) complex, rather than the larger 4(A2B2) complex. This smaller complex is sensitive to cellular metabolites indicating that it is an important regulatory isoform of GAPDH. This comparative study has highlighted considerable heterogeneity in PRK and GAPDH protein interactions between closely related species and the possible underlying physiological basis for this is discussed. PMID:21498632

Molecular Characterization of the Calvin Cycle Enzyme Phosphoribulokinase in the Stramenopile Alga Vaucheria litorea and the Plastid Hosting Mollusc Elysia chlorotica

PubMed Central

Rumpho, Mary E.; Pochareddy, Sirisha; Worful, Jared M.; Summer, Elizabeth J.; Bhattacharya, Debashish; Pelletreau, Karen N.; Tyler, Mary S.; Lee, Jungho; Manhart, James R.; Soule, Kara M.

2009-01-01

Phosphoribulokinase (PRK), a nuclear-encoded plastid-localized enzyme unique to the photosynthetic carbon reduction (Calvin) cycle, was cloned and characterized from the stramenopile alga Vaucheria litorea. This alga is the source of plastids for the mollusc (sea slug) Elysia chlorotica which enable the animal to survive for months solely by photoautotrophic CO2 fixation. The 1633-bp V. litorea prk gene was cloned and the coding region, found to be interrupted by four introns, encodes a 405-amino acid protein. This protein contains the typical bipartite target sequence expected of nuclear-encoded proteins that are directed to complex (i.e. four membrane-bound) algal plastids. De novo synthesis of PRK and enzyme activity were detected in E. chlorotica in spite of having been starved of V. litorea for several months. Unlike the algal enzyme, PRK in the sea slug did not exhibit redox regulation. Two copies of partial PRK-encoding genes were isolated from both sea slug and aposymbiotic sea slug egg DNA using PCR. Each copy contains the nucleotide region spanning exon 1 and part of exon 2 of V. litorea prk, including the bipartite targeting peptide. However, the larger prk fragment also includes intron 1. The exon and intron sequences of prk in E. chlorotica and V. litorea are nearly identical. These data suggest that PRK is differentially regulated in V. litorea and E. chlorotica and at least a portion of the V. litorea nuclear PRK gene is present in sea slugs that have been starved for several months. PMID:19995736

Autotrophy of green non-sulphur bacteria in hot spring microbial mats: biological explanations for isotopically heavy organic carbon in the geological record

NASA Technical Reports Server (NTRS)

van der Meer, M. T.; Schouten, S.; de Leeuw, J. W.; Ward, D. M.

2000-01-01

Inferences about the evidence of life recorded in organic compounds within the Earth's ancient rocks have depended on 13C contents low enough to be characteristic of biological debris produced by the well-known CO2 fixation pathway, the Calvin cycle. 'Atypically' high values have been attributed to isotopic alteration of sedimentary organic carbon by thermal metamorphism. We examined the possibility that organic carbon characterized by a relatively high 13C content could have arisen biologically from recently discovered autotrophic pathways. We focused on the green non-sulphur bacterium Chloroflexus aurantiacus that uses the 3-hydroxypropionate pathway for inorganic carbon fixation and is geologically significant as it forms modern mat communities analogous to stromatolites. Organic matter in mats constructed by Chloroflexus spp. alone had relatively high 13C contents (-14.9%) and lipids diagnostic of Chloroflexus that were also isotopically heavy (-8.9% to -18.5%). Organic matter in mats constructed by Chloroflexus in conjunction with cyanobacteria had a more typical Calvin cycle signature (-23.5%). However, lipids diagnostic of Chloroflexus were isotopically enriched (-15.1% to -24.1%) relative to lipids typical of cyanobacteria (-33.9% to -36.3%). This suggests that, in mats formed by both cyanobacteria and Chloroflexus, autotrophy must have a greater effect on Chloroflexus carbon metabolism than the photoheterotrophic consumption of cyanobacterial photosynthate. Chloroflexus cell components were also selectively preserved. Hence, Chloroflexus autotrophy and selective preservation of its products constitute one purely biological mechanism by which isotopically heavy organic carbon could have been introduced into important Precambrian geological features.

Horizontal transfer of a eukaryotic plastid-targeted protein gene to cyanobacteria

PubMed Central

Rogers, Matthew B; Patron, Nicola J; Keeling, Patrick J

2007-01-01

Background Horizontal or lateral transfer of genetic material between distantly related prokaryotes has been shown to play a major role in the evolution of bacterial and archaeal genomes, but exchange of genes between prokaryotes and eukaryotes is not as well understood. In particular, gene flow from eukaryotes to prokaryotes is rarely documented with strong support, which is unusual since prokaryotic genomes appear to readily accept foreign genes. Results Here, we show that abundant marine cyanobacteria in the related genera Synechococcus and Prochlorococcus acquired a key Calvin cycle/glycolytic enzyme from a eukaryote. Two non-homologous forms of fructose bisphosphate aldolase (FBA) are characteristic of eukaryotes and prokaryotes respectively. However, a eukaryotic gene has been inserted immediately upstream of the ancestral prokaryotic gene in several strains (ecotypes) of Synechococcus and Prochlorococcus. In one lineage this new gene has replaced the ancestral gene altogether. The eukaryotic gene is most closely related to the plastid-targeted FBA from red algae. This eukaryotic-type FBA once replaced the plastid/cyanobacterial type in photosynthetic eukaryotes, hinting at a possible functional advantage in Calvin cycle reactions. The strains that now possess this eukaryotic FBA are scattered across the tree of Synechococcus and Prochlorococcus, perhaps because the gene has been transferred multiple times among cyanobacteria, or more likely because it has been selectively retained only in certain lineages. Conclusion A gene for plastid-targeted FBA has been transferred from red algae to cyanobacteria, where it has inserted itself beside its non-homologous, functional analogue. Its current distribution in Prochlorococcus and Synechococcus is punctate, suggesting a complex history since its introduction to this group. PMID:17584924

Inter-species variation in the oligomeric states of the higher plant Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase and phosphoribulokinase.

PubMed

Howard, Thomas P; Lloyd, Julie C; Raines, Christine A

2011-07-01

In darkened leaves the Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) form a regulatory multi-enzyme complex with the small chloroplast protein CP12. GAPDH also forms a high molecular weight regulatory mono-enzyme complex. Given that there are different reports as to the number and subunit composition of these complexes and that enzyme regulatory mechanisms are known to vary between species, it was reasoned that protein-protein interactions may also vary between species. Here, this variation is investigated. This study shows that two different tetramers of GAPDH (an A2B2 heterotetramer and an A4 homotetramer) have the capacity to form part of the PRK/GAPDH/CP12 complex. The role of the PRK/GAPDH/CP12 complex is not simply to regulate the 'non-regulatory' A4 GAPDH tetramer. This study also demonstrates that the abundance and nature of PRK/GAPDH/CP12 interactions are not equal in all species and that whilst NAD enhances complex formation in some species, this is not sufficient for complex formation in others. Furthermore, it is shown that the GAPDH mono-enzyme complex is more abundant as a 2(A2B2) complex, rather than the larger 4(A2B2) complex. This smaller complex is sensitive to cellular metabolites indicating that it is an important regulatory isoform of GAPDH. This comparative study has highlighted considerable heterogeneity in PRK and GAPDH protein interactions between closely related species and the possible underlying physiological basis for this is discussed.

10. Historic American Buildings Survey Photocopy of Plate VIII (dated ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Historic American Buildings Survey Photocopy of Plate VIII (dated 1889) in John Calvin Stevens and Albert Winslow Cobb, Examples of American Domestic Architecture, New York, William T. Comstock, 1889 PLANS AND INTERIOR DETAILS, 1889 - John Calvin Stevens House, 52 Bowdoin Street, Portland, Cumberland County, ME

Calvin Brainerd Cady: Thought and Feeling in the Study of Music.

ERIC Educational Resources Information Center

Shiraishi, Fumiko

1999-01-01

Presents the life and work of Calvin Brainerd Cady, an influential U.S. music educator who developed a theory of music education that emphasized the unification of children's thoughts and feelings. Discusses Cady's educational practices in depth and how his work remains relevant to current music-education practices. (DSK)

Voices in International School Psychology: Interviews in Honor of Calvin D. Catterall.

ERIC Educational Resources Information Center

Culbertson, Frances M.

Following a brief memorial message and a dedicatory tribute to Calvin D. Catterall, a leader in the field of school psychology, this volume provides a description of the origins of the International School Psychology Association and interviews with five school psychologists: Bram Norwich, University of London, England; Tony Cline, London, England;…

Should Medicare Reimburse Providers for Weight Loss Interventions?

ERIC Educational Resources Information Center

Kaplan, Robert M.

2007-01-01

This issue of the American Psychologist (April 2007) includes two reviews of the literature on the effects of behavioral programs to reduce body weight. One review (T. Mann et al., 2007) concentrates on dietary interventions and finds little evidence that diets are of benefit. The second review (L. H. Powell, J. E. Calvin III, & J. E. Calvin Jr.,…

C1 metabolism plays an important role during formaldehyde metabolism and detoxification in petunia under liquid HCHO stress.

PubMed

Zhang, Wei; Tang, Lijuan; Sun, Huiqun; Han, Shuang; Wang, Xinjia; Zhou, Shengen; Li, Kunzhi; Chen, Limei

2014-10-01

Petunia hybrida is a model ornamental plant grown worldwide. To understand the HCHO-uptake efficiency and metabolic mechanism of petunia, the aseptic petunia plants were treated in HCHO solutions. An analysis of HCHO-uptake showed that petunia plants effectively removed HCHO from 2, 4 and 6 mM HCHO solutions. The (13)C NMR analyses indicated that H(13)CHO was primarily used to synthesize [5-(13)C]methionine (Met) via C1 metabolism in petunia plants treated with 2 mM H(13)CHO. Pretreatment with cyclosporin A (CSA) or l-carnitine (LC), the inhibitors of mitochondrial permeability transition pores, did not affect the synthesis of [5-(13)C]Met in petunia plants under 2 mM H(13)CHO stress, indicating that the Met-generated pathway may function in the cytoplasm. Under 4 or 6 mM liquid H(13)CHO stress, H(13)CHO metabolism in petunia plants produced considerable amount of H(13)COOH and [2-(13)C]glycine (Gly) through C1 metabolism and a small amount of [U-(13)C]Gluc via the Calvin Cycle. Pretreatment with CSA or LC significantly inhibited the production of [2-(13)C]Gly in 6 mM H(13)CHO-treated petunia plants, which suggests that chloroplasts and peroxisomes might be involved in the generation of [2-(13)C]Gly. These results revealed that the C1 metabolism played an important role, whereas the Calvin Cycle had only a small contribution during HCHO metabolism and detoxification in petunia under liquid HCHO stress. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Prompt and easy activation by specific thioredoxins of calvin cycle enzymes of Arabidopsis thaliana associated in the GAPDH/CP12/PRK supramolecular complex.

PubMed

Marri, Lucia; Zaffagnini, Mirko; Collin, Valérie; Issakidis-Bourguet, Emmanuelle; Lemaire, Stéphane D; Pupillo, Paolo; Sparla, Francesca; Miginiac-Maslow, Myroslawa; Trost, Paolo

2009-03-01

The Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) can form under oxidizing conditions a supramolecular complex with the regulatory protein CP12. Both GAPDH and PRK activities are inhibited within the complex, but they can be fully restored by reduced thioredoxins (TRXs). We have investigated the interactions of eight different chloroplast thioredoxin isoforms (TRX f1, m1, m2, m3, m4, y1, y2, x) with GAPDH (A(4), B(4), and B(8) isoforms), PRK and CP12 (isoform 2), all from Arabidopsis thaliana. In the complex, both A(4)-GAPDH and PRK were promptly activated by TRX f1, or more slowly by TRXs m1 and m2, but all other TRXs were ineffective. Free PRK was regulated by TRX f1, m1, or m2, while B(4)- and B(8)-GAPDH were absolutely specific for TRX f1. Interestingly, reductive activation of PRK caged in the complex was much faster than reductive activation of free oxidized PRK, and activation of A(4)-GAPDH in the complex was much faster (and less demanding in terms of reducing potential) than activation of free oxidized B(4)- or B(8)-GAPDH. It is proposed that CP12-assembled supramolecular complex may represent a reservoir of inhibited enzymes ready to be released in fully active conformation following reduction and dissociation of the complex by TRXs upon the shift from dark to low light. On the contrary, autonomous redox-modulation of GAPDH (B-containing isoforms) would be more suited to conditions of very active photosynthesis.

Antisense Suppression of the Small Chloroplast Protein CP12 in Tobacco Alters Carbon Partitioning and Severely Restricts Growth1[W

PubMed Central

Howard, Thomas P.; Fryer, Michael J.; Singh, Prashant; Metodiev, Metodi; Lytovchenko, Anna; Obata, Toshihiro; Fernie, Alisdair R.; Kruger, Nicholas J.; Quick, W. Paul; Lloyd, Julie C.; Raines, Christine A.

2011-01-01

The thioredoxin-regulated chloroplast protein CP12 forms a multienzyme complex with the Calvin-Benson cycle enzymes phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). PRK and GAPDH are inactivated when present in this complex, a process shown in vitro to be dependent upon oxidized CP12. The importance of CP12 in vivo in higher plants, however, has not been investigated. Here, antisense suppression of CP12 in tobacco (Nicotiana tabacum) was observed to impact on NAD-induced PRK and GAPDH complex formation but had little effect on enzyme activity. Additionally, only minor changes in photosynthetic carbon fixation were observed. Despite this, antisense plants displayed changes in growth rates and morphology, including dwarfism and reduced apical dominance. The hypothesis that CP12 is essential to separate oxidative pentose phosphate pathway activity from Calvin-Benson cycle activity, as proposed in cyanobacteria, was tested. No evidence was found to support this role in tobacco. Evidence was seen, however, for a restriction to malate valve capacity, with decreases in NADP-malate dehydrogenase activity (but not protein levels) and pyridine nucleotide content. Antisense repression of CP12 also led to significant changes in carbon partitioning, with increased carbon allocation to the cell wall and the organic acids malate and fumarate and decreased allocation to starch and soluble carbohydrates. Severe decreases were also seen in 2-oxoglutarate content, a key indicator of cellular carbon sufficiency. The data presented here indicate that in tobacco, CP12 has a role in redox-mediated regulation of carbon partitioning from the chloroplast and provides strong in vivo evidence that CP12 is required for normal growth and development in plants. PMID:21865489

Large Fractions of CO2-Fixing Microorganisms in Pristine Limestone Aquifers Appear To Be Involved in the Oxidation of Reduced Sulfur and Nitrogen Compounds

PubMed Central

Herrmann, Martina; Rusznyák, Anna; Akob, Denise M.; Schulze, Isabel; Opitz, Sebastian; Totsche, Kai Uwe

2015-01-01

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed—upper and lower—limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO2 via the Calvin cycle, with abundances of cbbM and cbbL genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 × 103 to 6 × 106 genes liter−1 over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO2-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO2 fixation in environments with strong oxygen and CO2 fluctuations. The genera Sulfuricella and Nitrosomonas were represented by read fractions of up to 78 and 33%, respectively, within the cbbM and cbbL transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO2 fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds. PMID:25616797

Carbon transitions from either Calvin cycle or transitory starch to heteroglycans as revealed by (14) C-labeling experiments using protoplasts from Arabidopsis.

PubMed

Malinova, Irina; Steup, Martin; Fettke, Joerg

2013-09-01

Plants metabolize transitory starch by precisely coordinated plastidial and cytosolic processes. The latter appear to include the action of water-soluble heteroglycans (SHGin ) whose monosaccharide pattern is similar to that of apoplastic glycans (SHGex ) but, unlike SHGex , SHGin strongly interacts with glucosyl transferases. In this study, we analyzed starch metabolism using mesophyll protoplasts from wild-type plants and two knock-out mutants [deficient in the cytosolic transglucosidase, disproportionating isoenzyme 2 (DPE2) or the plastidial phosphoglucomutase (PGM1)] from Arabidopsis thaliana. Protoplasts prelabeled by photosynthetic (14) CO2 fixation were transferred to an unlabeled medium and were darkened or illuminated. Carbon transitions from the Calvin cycle or from starch to both SHGin and SHGex were analyzed. In illuminated protoplasts, starch turn-over was undetectable but darkened protoplasts continuously degraded starch. During illumination, neither the total (14) C content nor the labeling patterns of the sugar residues of SHGin were significantly altered but both the total amount and the labeling of the constituents of SHGex increased with time. In darkened protoplasts, the (14) C-content of most of the sugar residues of SHGin transiently and strongly increased and then declined. This effect was not observed in any SHGex constituent. In darkened DPE2-deficient protoplasts, none of the SHGin constituents exhibited an essential transient increase in labeling. In contrast, some residues of SHGin from the PGM1 mutant exhibited a transient increase in label but this effect significantly differed from that of the wild type. Two conclusions are reached: first, SHGin and SHGex exert different metabolic functions and second, SHGin is directly involved in starch degradation. © 2013 Scandinavian Plant Physiology Society.

Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata).

PubMed

Kim, Gwang Hoon; Jeong, Hae Jin; Yoo, Yeong Du; Kim, Sunju; Han, Ji Hee; Han, Jong Won; Zuccarello, Giuseppe C

2013-01-01

The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons) obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value

Proteomic and metabolic profiles of Cakile maritima Scop. Sea Rocket grown in the presence of cadmium.

PubMed

Taamalli, Manel; D'Alessandro, Angelo; Marrocco, Cristina; Gevi, Federica; Timperio, Anna Maria; Zolla, Lello

2015-04-01

Recent physiological reports have documented how Cakile maritima Scop. Sea Rocket could accumulate high doses of Cd without altering its physiological parameters. In the present study, we performed an integrated proteomics (2DE) and metabolomics (HPLC-MS) investigation to determine the molecular mechanisms underlying cadmium (Cd) tolerance of this halophyte. Peculiar features were observed: (i) up-regulation of thiol compound anabolism, including glutathione and phytochelatin homeostasis, which allows an intracellular chelation of Cd and its compartmentalization into vacuole by a significant up-regulation of vacuolar transporters; (ii) up-regulation of the PPP and Calvin cycle (both at the enzyme and metabolite level), which utterly promoted the maintenance of NADPH/NADP(+) homeostasis, other than the accumulation of triose-phosphates (serving as anabolic intermediates for triacylglycerol biosynthesis) and the glyoxylate precursor phosphoglycolate, to promote photorespiration and consequently CO2 release. An up-regulation of carbonic anhydrase was also observed. This halophyte is also correlated with a highly efficient antioxidant system, especially a high up-regulation of SOD1, resulting more efficient in coping with heavy metals stress than common plants. Interestingly, exposure to high Cd concentrations partly affected photosystem integrity and metabolic activity, through the up-regulation of enzymes from the Calvin cycle and glutathione-ascorbate homeostasis and PAP3 which stabilizes thylakoid membrane structures. In addition, up-regulation of Peptidyl-prolyl isomerase CYP38 increases stability and biogenesis of PSII. Finally, metabolomics results confirmed proteomics and previous physiological evidence, also suggesting that osmoprotectants, betaine and proline, together with plant hormones, methyl jasmonate and salicylic acid, might be involved in mediating responses to Cd-induced stress. Taken together, these peculiar features confirm that Cakile maritima Scop. Sea Rocket seemed to be naturally equipped to withstand even high doses of Cd pollution.

The Framing of Calvin Klein: A Frame Analysis of Media Discourse about the August 1995 Calvin Klein Jeans Advertising Campaign.

ERIC Educational Resources Information Center

Tucker, Lauren R.

1998-01-01

Deconstructs the "kiddie porn" media frame used by the industry and mainstream media to characterize Klein's ad campaign. Extends scholarship on the construction of youth in the media, showing how the kiddie-porn frame produces and reproduces common-sense beliefs about the nature of youth. Suggests a metadiscourse encompassing the…

Ribulose 1,5-bisphosphate carboxylase and phosphoribulokinase in Prochloron

NASA Technical Reports Server (NTRS)

Berhow, M. A.; Mcfadden, B. A.

1983-01-01

Ribulose 1,5-bisphosphate (RuBP) carboxylase and phosphoribulokinase, enzymes in the reductive pentose-phosphate cycle, were measured in cell-free extracts of Prochloran didemni. The partial purification and characterization of RuBP carboxylase were described. Prochloron RuBP carboxylase, when purified by isopycnic centrifugation in reoriented linear 0.2 to 0.8 M sucrose gradients, sedimented to a position which corresponded to that of the 520,000-dalton spinach enzyme. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the Prochloron enzyme was composed of large and small subunits (MW = 57,500 and 18,800). Though results established that the enzymes RuBP carboxylase and phosphoribulokinase were present in levels comparable to other CO2-fixing microorganisms, it was suggested that other enzymes in the Calvin cycle limit growth or that additional enzymic insufficiencies exist.

"Blest be the Tie That Binds" Catastrophically Confused Calvinism (Will America Destest to Its Own Demise?)

NASA Astrophysics Data System (ADS)

Putnam, Robert David

Calvin never failed to stir controversy; his pen never dipped a second time into the inkwell before issues were raised and battle lines were drawn in the theological sand. His ideas about God and scripture are critiqued and debated among theologians; engaged by historians and sociologists as well as preached by clergy well into the twenty-first century. But with all that scholarly discourse, Calvin's world-changing influence on western civilization, arguably the real story, seems to go largely unnoticed and unrealized. Yet it shaped the colonies of the new world, framed thinking as the founding fathers authored the Constitution of the United States, affected society's views about slavery leading into the American Civil War, and today pulls the strings from behind the curtain of culture making science, the arts, academia, the media, entertainment, religion, and the rule of governments all over the world dance, like so many marionettes in a children's puppet show. Calvin's distinctive theological ideas seemed to have a unique propensity to evoke cultural and linguistic absolutes often leading to extremisms in their applications, perhaps in ways that Calvin himself never intended. These distorted extremes created a sort of cultural rainbow overarching societal skies in Europe, spreading to the United States, and through America's influence, now extend around the world. Yet few bother to look up to take notice of the sociological colors above them, let alone respond to them. Comprehending the veracity then of such declaratives, will be realized in this treatise by tracing an anthropological lineage of John Calvin's unique view of theology that has been culturally sown into the societal fabric of Europe and even more in the United States; assimilating religion, the economy, politics, government, education, the arts, and the sciences; uncovering his influence in evangelical Christianity, frequently perceived as conflicted, judgmental, condescending, and overbearing by certain secularized segments of society who arguably and ironically spawn their critiques via the same religious Calvinistic extremism they espouse to despise, simply rebranded and masked as non-religious and secular.

Extensible Interest Management for Scalable Persistent Distributed Virtual Environments

DTIC Science & Technology

1999-12-01

Calvin, Cebula et al. 1995; Morse, Bic et al. 2000) uses a two grid, with each grid cell having two multicast addresses. An entity expresses interest...Entity distribution for experimental runs 78 s I * • ...... ^..... * * a» Sis*«*»* 1 ***** Jj |r...Multiple Users and Shared Applications with VRML. VRML 97, Monterey, CA. pp. 33-40. Calvin, J. O., D. P. Cebula , et al. (1995). Data Subscription in

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartman, F.C.

This report describes the Jacques Monod Conference on Intracellular Redox Control in Animals, Plants and Microrganisms by Thioredoxin and Glutaredoxin Systems,'' which was held in Roscoff, France, on July 1--7, 1990. I was given the opportunity to lecture on my group's work concerning chemical characterization of phosphoribulokinase and its regulation by thioredoxin. I was also asked to chair a half-day session on thioredoxin reductases, a family of regulatory proteins that are involved in processes as diverse as DNA replication in mammals and carbon fluxes through the Calvin cycle in plants. As a major theme of the conference was structure/function relationshipsmore » of proteins, most topics were of direct relevance to many research endeavors in the Biology Division of ORNL.« less

Changes induced by the Pepper mild mottle tobamovirus on the chloroplast proteome of Nicotiana benthamiana.

PubMed

Pineda, M; Sajnani, C; Barón, M

2010-01-01

We have analyzed the chloroplast proteome of Nicotiana benthamiana using two-dimensional gel electrophoresis and mass spectrometry followed by a database search. In order to improve the resolution of the two-dimensional electrophoresis gels, we have made separate maps for the low and the high pH range. At least 200 spots were detected. We identified 72 polypeptides, some being isoforms of different multiprotein families. In addition, changes in this chloroplast proteome induced by the infection with the Spanish strain of the Pepper mild mottle virus were investigated. Viral infection induced the down-regulation of several chloroplastidic proteins involved in both the photosynthetic electron-transport chain and the Benson-Calvin cycle.

Carbon isotopic composition of individual Precambrian microfossils

NASA Technical Reports Server (NTRS)

House, C. H.; Schopf, J. W.; McKeegan, K. D.; Coath, C. D.; Harrison, T. M.; Stetter, K. O.

2000-01-01

Ion microprobe measurements of carbon isotope ratios were made in 30 specimens representing six fossil genera of microorganisms petrified in stromatolitic chert from the approximately 850 Ma Bitter Springs Formation, Australia, and the approximately 2100 Ma Gunflint Formation, Canada. The delta 13C(PDB) values from individual microfossils of the Bitter Springs Formation ranged from -21.3 +/- 1.7% to -31.9 +/- 1.2% and the delta 13C(PDB) values from microfossils of the Gunflint Formation ranged from -32.4 +/- 0.7% to -45.4 +/- 1.2%. With the exception of two highly 13C-depleted Gunflint microfossils, the results generally yield values consistent with carbon fixation via either the Calvin cycle or the acetyl-CoA pathway. However, the isotopic results are not consistent with the degree of fractionation expected from either the 3-hydroxypropionate cycle or the reductive tricarboxylic acid cycle, suggesting that the microfossils studied did not use either of these pathways for carbon fixation. The morphologies of the microfossils suggest an affinity to the cyanobacteria, and our carbon isotopic data are consistent with this assignment.

Large fractions of CO2-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds

USGS Publications Warehouse

Herrmann, Martina; Rusznyák, Anna; Akob, Denise M.; Schulze, Isabel; Opitz, Sebastian; Totsche, Kai Uwe; Küsel, Kirsten

2015-01-01

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed—upper and lower—limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO2 via the Calvin cycle, with abundances of cbbM and cbbL genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 × 103 to 6 × 106 genes liter−1 over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO2-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO2 fixation in environments with strong oxygen and CO2 fluctuations. The genera Sulfuricellaand Nitrosomonas were represented by read fractions of up to 78 and 33%, respectively, within the cbbM and cbbL transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO2 fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds.

Type-f thioredoxins have a role in the short-term activation of carbon metabolism and their loss affects growth under short-day conditions in Arabidopsis thaliana.

PubMed

Naranjo, Belén; Diaz-Espejo, Antonio; Lindahl, Marika; Cejudo, Francisco Javier

2016-03-01

Redox regulation plays a central role in the adaptation of chloroplast metabolism to light. Extensive biochemical analyses in vitro have identified f-type thioredoxins (Trxs) as the most important catalysts for light-dependent reduction and activation of the enzymes of the Calvin-Benson cycle. However, the precise function of type f Trxs in vivo and their impact on plant growth are still poorly known. To address this issue we have generated an Arabidopsis thaliana double knock-out mutant, termed trxf1f2, devoid of both f1 and f2 Trxs. Despite the essential function previously proposed for f-type Trxs, the visible phenotype of the trxf1f2 double mutant was virtually indistinguishable from the wild type when grown under a long-day photoperiod. However, the Trx f-deficient plants showed growth inhibition under a short-day photoperiod which was not rescued at high light intensity. The absence of f-type Trxs led to significantly lower photosynthetic electron transport rates and higher levels of non-photochemical energy quenching. Notably, the Trx f null mutant suffered from a shortage of photosystem I electron acceptors and delayed activation of carbon dioxide fixation following a dark-light transition. Two redox-regulated Calvin-Benson cycle enzymes, fructose 1,6-bisphosphatase (FBPase) and Rubisco activase, showed retarded and incomplete reduction in the double mutant upon illumination, compared with wild-type plants. These results show that the function of f-type Trxs in the rapid activation of carbon metabolism in response to light is not entirely compensated for by additional plastid redox systems, and suggest that these Trxs have an important role in the light adjustment of photosynthetic metabolism. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Final Report for research on The Glucose 6-Phosphate Shunt Around the Calvin-Benson Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharkey, Thomas D.

In this research, photosynthetic carbon metabolism was studied to identify mechanisms by which plants store energy from sunlight as carbon compounds, especially sugars. Conditions were identified in which carbon appeared to flow backwards from outside the photosynthetic compartment (chloroplast) back into it. A specific gene product was manipulated to make the flow bigger or smaller. Preventing the flow (by eliminating the gene) had little effect on plant growth but increasing the flow, by overexpressing the gene, caused the plants to become extremely sensitive to changes in light. Plants with the gene overexpressed had high rates of cyclic electron flow, themore » photosynthetic electron transport pathway that occurs when plants need more of the energy molecule ATP. These and other observations led us to conclude that a metabolic pathway that is normally turned off because it is counter-productive during photosynthesis, in fact occurs at about 10% of the rate of normal photosynthesis. This creates an inefficiency but may stabilize photosynthesis allowing it to cope with the very large and rapid changes that leaves experience such as the hundred-fold changes in light intensity that can occur in seconds on a partly cloudy day. We also concluded that the back flow of carbon into chloroplasts could be important at high rates of photosynthesis allowing increased rates of starch synthesis. Starch synthesis allows plants to store sugars during the day for use at night. At high rates of photosynthesis starch synthesis becomes very important to protect against end-product inhibition of photosynthesis. This research identified two metabolic pathways that extend the primary carbon fixation pathway called the Calvin-Benson cycle. These pathway extensions are now called the cytosolic bypass and the glucose 6-phosphate shunt. This improvement in our understanding of carbon metabolism of photosynthesis will guide efforts to increase photosynthesis to increase production of food, fuel, and fiber.« less

A short history of RubisCO: the rise and fall (?) of Nature's predominant CO2 fixing enzyme.

PubMed

Erb, Tobias J; Zarzycki, Jan

2018-02-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is arguably one of the most abundant proteins in the biosphere and a key enzyme in the global carbon cycle. Although RubisCO has been intensively studied, its evolutionary origins and rise as Nature's most dominant carbon dioxide (CO 2 )-fixing enzyme still remain in the dark. In this review we will bring together biochemical, structural, physiological, microbiological, as well as phylogenetic data to speculate on the evolutionary roots of the CO 2 -fixation reaction of RubisCO, the emergence of RubisCO-based autotrophic CO 2 -fixation in the context of the Calvin-Benson-Bassham cycle, and the further evolution of RubisCO into the 'RubisCOsome', a complex of various proteins assembling and interacting with the enzyme to improve its operational capacity (functionality) under different biological and environmental conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Calvin-Rehoboth Robotic Twin Telescopes

NASA Astrophysics Data System (ADS)

Haarsma, D. B.; Molnar, L. A.; VanBaak, D. A.

2004-12-01

The astronomy program at Calvin College, like many small colleges, is limited by poor weather and light pollution at its midwestern campus and by limited free time on the part of its astronomy faculty. Nonetheless we believe direct access to the physical universe is key to the science education both of science majors and nonmajors. Recent advances in hardware and software for modest robotic telescopes have made it possible for colleges like ours to incorporate the use of a remote bservatory into our curriculum within typical financial and time constraints. In this poster we make our first report on the installation of two robotic telescopes (one on campus and one at a remote site in New Mexico) using largely off-the-shelf components. Students learn first with the local telescope in order to understand the equipment and procedures, but obtain the majority of their data with the remote telescope. Equipment development is done first with the local telescope, and then implemented on the remote telescope (where time spent in development is difficult). We received an NSF CCLI grant and matching college funds in the summer of 2002. The local telescope was installed in the spring of 2003, and the New Mexico telescope was ready for remote operation in January 2004. Our poster will describe our equipment choices, including a few components (such as an equipment rack for the back end of the telescope) which we designed ourselves. It will also detail classroom use of the equipment in its first two semesters by students at a range of levels. A copy of the poster and many additional details of the project are available on the Calvin observatory website, http://www.calvin.edu/observatory/.

Proceedings of the 1982 Army Science Conference Held at the United States Military Academy, West Point, New York on 15-18 June 1982. Volume I. Principal Authors A through G.

DTIC Science & Technology

1982-06-18

McKnight, W. B.Barsam, Helena F. See Simutis, Zita M. 3 273 Basso, Michael J. See McCreery, M. J. 2 357 Bates, Calvin See Fischer , Paul 1 399 Baussus...F. 3 1 Berg, Ri chard See Lunardi ni, Virgil J. 2 263 Berkhimer, Karl See Sturdivan, Larry M. 4 209 Bertin, John J. VMultiple Launch Rocket System...W. Fischer , Paul A Novel Beom Bunching Concept for 1 399 Sates,, Calvin Millimeter Wave Tubes Hartley, Joseph Friedman, Melvin H. New Viewpoints in

Exploring stress tolerance mechanism of evolved freshwater strain Chlorella sp. S30 under 30 g/L salt.

PubMed

Li, Xuyang; Yuan, Yizhong; Cheng, Dujia; Gao, Juan; Kong, Lingzhao; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

2018-02-01

Enhancement of stress tolerance to high concentration of salt and CO 2 is beneficial for CO 2 capture by microalgae. Adaptive evolution was performed for improving the tolerance of a freshwater strain, Chlorella sp. AE10, to 30 g/L salt. A resulting strain denoted as Chlorella sp. S30 was obtained after 46 cycles (138 days). The stress tolerance mechanism was analyzed by comparative transcriptomic analysis. Although the evolved strain could tolerate 30 g/L salt, high salinity caused loss to photosynthesis, oxidative phosphorylation, fatty acid biosynthesis and tyrosine metabolism. The related genes of antioxidant enzymes, CO 2 fixation, amino acid biosynthesis, central carbon metabolism and ABC transporter proteins were up-regulated. Besides the up-regulation of several genes in Calvin-Benson cycle, they were also identified in C4 photosynthetic pathway and crassulacean acid metabolism pathway. They were essential for the survival and CO 2 fixation of Chlorella sp. S30 under 30 g/L salt and 10% CO 2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Yu Ping; Cheng, Fei; Zhou, Yan Hong

Highlights: Black-Right-Pointing-Pointer Activity of certain Calvin cycle enzymes and CO{sub 2} assimilation are induced by BRs. Black-Right-Pointing-Pointer BRs upregulate the activity of the ascorbate-glutathione cycle in the chloroplasts. Black-Right-Pointing-Pointer BRs increase the chloroplast thiol reduction state. Black-Right-Pointing-Pointer A BR-induced reducing environment increases the stability of photosynthetic enzymes. -- Abstract: Brassinosteroids (BRs) play important roles in plant growth, development, photosynthesis and stress tolerance; however, the mechanism underlying BR-enhanced photosynthesis is currently unclear. Here, we provide evidence that an increase in the BR level increased the quantum yield of PSII, activities of Rubisco activase (RCA) and fructose-1,6-bisphosphatase (FBPase), and CO{sub 2} assimilation.more » BRs upregulated the transcript levels of genes and activity of enzymes involved in the ascorbate-glutathione cycle in the chloroplasts, leading to an increased ratio of reduced (GSH) to oxidized (GSSG) glutathione in the chloroplasts. An increased GSH/GSSG ratio protected RCA from proteolytic digestion and increased the stability of redox-sensitive enzymes in the chloroplasts. These results strongly suggest that BRs are capable of regulating the glutathione redox state in the chloroplasts through the activation of the ascorbate-glutathione cycle. The resulting increase in the chloroplast thiol reduction state promotes CO{sub 2} assimilation, at least in part, by enhancing the stability and activity of redox-sensitive photosynthetic enzymes through post-translational modifications.« less

Phylogeny of C4-photosynthesis enzymes based on algal transcriptomic and genomic data supports an archaeal/proteobacterial origin and multiple duplication for most C4-related genes.

PubMed

Chi, Shan; Wu, Shuangxiu; Yu, Jun; Wang, Xumin; Tang, Xuexi; Liu, Tao

2014-01-01

Both Calvin-Benson-Bassham (C3) and Hatch-Slack (C4) cycles are most important autotrophic CO2 fixation pathways on today's Earth. C3 cycle is believed to be originated from cyanobacterial endosymbiosis. However, studies on evolution of different biochemical variants of C4 photosynthesis are limited to tracheophytes and origins of C4-cycle genes are not clear till now. Our comprehensive analyses on bioinformatics and phylogenetics of novel transcriptomic sequencing data of 21 rhodophytes and 19 Phaeophyceae marine species and public genomic data of more algae, tracheophytes, cyanobacteria, proteobacteria and archaea revealed the origin and evolution of C4 cycle-related genes. Almost all of C4-related genes were annotated in extensive algal lineages with proteobacterial or archaeal origins, except for phosphoenolpyruvate carboxykinase (PCK) and aspartate aminotransferase (AST) with both cyanobacterial and archaeal/proteobacterial origin. Notably, cyanobacteria may not possess complete C4 pathway because of the flawed annotation of pyruvate orthophosphate dikinase (PPDK) genes in public data. Most C4 cycle-related genes endured duplication and gave rise to functional differentiation and adaptation in different algal lineages. C4-related genes of NAD-ME (NAD-malic enzyme) and PCK subtypes exist in most algae and may be primitive ones, while NADP-ME (NADP-malic enzyme) subtype genes might evolve from NAD-ME subtype by gene duplication in chlorophytes and tracheophytes.

Identifying the missing steps of the autotrophic 3-hydroxypropionate CO2 fixation cycle in Chloroflexus aurantiacus.

PubMed

Zarzycki, Jan; Brecht, Volker; Müller, Michael; Fuchs, Georg

2009-12-15

The phototrophic bacterium Chloroflexus aurantiacus uses a yet unsolved 3-hydroxypropionate cycle for autotrophic CO(2) fixation. It starts from acetyl-CoA, with acetyl-CoA and propionyl-CoA carboxylases acting as carboxylating enzymes. In a first cycle, (S)-malyl-CoA is formed from acetyl-CoA and 2 molecules of bicarbonate. (S)-Malyl-CoA cleavage releases the CO(2) fixation product glyoxylate and regenerates the starting molecule acetyl-CoA. Here we complete the missing steps devoted to glyoxylate assimilation. In a second cycle, glyoxylate is combined with propionyl-CoA, an intermediate of the first cycle, to form beta-methylmalyl-CoA. This condensation is followed by dehydration to mesaconyl-C1-CoA. An unprecedented CoA transferase catalyzes the intramolecular transfer of the CoA moiety to the C4 carboxyl group of mesaconate. Mesaconyl-C4-CoA then is hydrated by an enoyl-CoA hydratase to (S)-citramalyl-CoA. (S)-Citramalyl-CoA is cleaved into acetyl-CoA and pyruvate by a tri-functional lyase, which previously cleaved (S)-malyl-CoA and formed beta-methylmalyl-CoA. Thus, the enigmatic disproportionation of glyoxylate and propionyl-CoA into acetyl-CoA and pyruvate is solved in an elegant and economic way requiring only 3 additional enzymes. The whole bicyclic pathway results in pyruvate formation from 3 molecules of bicarbonate and involves 19 steps but only 13 enzymes. Elements of the 3-hydroxypropionate cycle may be used for the assimilation of small organic molecules. The 3-hydroxypropionate cycle is compared with the Calvin-Benson-Bassham cycle and other autotrophic pathways.

Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics.

PubMed

Wang, Xiaoli; Xu, Chenxi; Cai, Xiaofeng; Wang, Quanhua; Dai, Shaojun

2017-10-20

Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP)-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO₂ exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.

Diversity of Total Bacterial Communities and Chemoautotrophic Populations in Sulfur-Rich Sediments of Shallow-Water Hydrothermal Vents off Kueishan Island, Taiwan.

PubMed

Wang, Li; Cheung, Man Kit; Liu, Rulong; Wong, Chong Kim; Kwan, Hoi Shan; Hwang, Jiang-Shiou

2017-04-01

Shallow-water hydrothermal vents (HTVs) are an ecologically important habitat with a geographic origin similar to that of deep-sea HTVs. Studies on shallow-water HTVs have not only facilitated understanding of the influences of vents on local ecosystems but also helped to extend the knowledge on deep-sea vents. In this study, the diversity of bacterial communities in the sediments of shallow-water HTVs off Kueishan Island, Taiwan, was investigated by examining the 16S ribosomal RNA gene as well as key functional genes involved in chemoautotrophic carbon fixation (aclB, cbbL and cbbM). In the vent area, Sulfurovum and Sulfurimonas of Epsilonproteobacteria appeared to dominate the benthic bacterial community. Results of aclB gene analysis also suggested involvement of these bacteria in carbon fixation using the reductive tricarboxylic acid (rTCA) cycle. Analysis of the cbbM gene showed that Alphaproteobacterial members such as the purple non-sulfur bacteria were the major chemoautotrophic bacteria involving in carbon fixation via the Calvin-Benson-Bassham (CBB) cycle. However, they only accounted for <2% of the total bacterial community in the vent area. These findings suggest that the rTCA cycle is the major chemoautotrophic carbon fixation pathway in sediments of the shallow-water HTVs off Kueishan Island.

Proteome-wide analysis and diel proteomic profiling of the cyanobacterium Arthrospira platensis PCC 8005.

PubMed

Matallana-Surget, Sabine; Derock, Jérémy; Leroy, Baptiste; Badri, Hanène; Deschoenmaeker, Frédéric; Wattiez, Ruddy

2014-01-01

The filamentous cyanobacterium Arthrospira platensis has a long history of use as a food supply and it has been used by the European Space Agency in the MELiSSA project, an artificial microecosystem which supports life during long-term manned space missions. This study assesses progress in the field of cyanobacterial shotgun proteomics and light/dark diurnal cycles by focusing on Arthrospira platensis. Several fractionation workflows including gel-free and gel-based protein/peptide fractionation procedures were used and combined with LC-MS/MS analysis, enabling the overall identification of 1306 proteins, which represents 21% coverage of the theoretical proteome. A total of 30 proteins were found to be significantly differentially regulated under light/dark growth transition. Interestingly, most of the proteins showing differential abundance were related to photosynthesis, the Calvin cycle and translation processes. A novel aspect and major achievement of this work is the successful improvement of the cyanobacterial proteome coverage using a 3D LC-MS/MS approach, based on an immobilized metal affinity chromatography, a suitable tool that enabled us to eliminate the most abundant protein, the allophycocyanin. We also demonstrated that cell growth follows a light/dark cycle in A. platensis. This preliminary proteomic study has highlighted new characteristics of the Arthrospira platensis proteome in terms of diurnal regulation.

Proteome-Wide Analysis and Diel Proteomic Profiling of the Cyanobacterium Arthrospira platensis PCC 8005

PubMed Central

Matallana-Surget, Sabine; Derock, Jérémy; Leroy, Baptiste; Badri, Hanène; Deschoenmaeker, Frédéric; Wattiez, Ruddy

2014-01-01

The filamentous cyanobacterium Arthrospira platensis has a long history of use as a food supply and it has been used by the European Space Agency in the MELiSSA project, an artificial microecosystem which supports life during long-term manned space missions. This study assesses progress in the field of cyanobacterial shotgun proteomics and light/dark diurnal cycles by focusing on Arthrospira platensis. Several fractionation workflows including gel-free and gel-based protein/peptide fractionation procedures were used and combined with LC-MS/MS analysis, enabling the overall identification of 1306 proteins, which represents 21% coverage of the theoretical proteome. A total of 30 proteins were found to be significantly differentially regulated under light/dark growth transition. Interestingly, most of the proteins showing differential abundance were related to photosynthesis, the Calvin cycle and translation processes. A novel aspect and major achievement of this work is the successful improvement of the cyanobacterial proteome coverage using a 3D LC-MS/MS approach, based on an immobilized metal affinity chromatography, a suitable tool that enabled us to eliminate the most abundant protein, the allophycocyanin. We also demonstrated that cell growth follows a light/dark cycle in A. platensis. This preliminary proteomic study has highlighted new characteristics of the Arthrospira platensis proteome in terms of diurnal regulation. PMID:24914774

Azolla-Anabaena Relationship

PubMed Central

Ray, Thomas B.; Mayne, Berger C.; Toia, Robert E.; Peters, Gerald A.

1979-01-01

Photosynthesis in the Azolla-Anabaena association was characterized with respect to photorespiration, early products of photosynthesis, and action spectra. Photorespiration as evidenced by an O2 inhibition of photosynthesis and an O2-dependent CO2 compensation concentration was found to occur in the association, and endophyte-free fronds, but not in the endophytic Anabaena. Analysis of the early products of photosynthesis indicated that both the fern and cyanobacterium fix CO2 via the Calvin cycle. The isolated endophytic Anabaena did not release significant amounts of amino acids synthesized from recently fixed carbon. The action spectra for photosynthesis in the Azolla-Anabaena association indicated that the maximum quantum yield is between 650 and 670 nanometers, while in the endophyte the maximum is between 580 and 640 nanometers. Although the endophytic cyanobacterium is photosynthetically competent, any contribution it makes to photosynthesis in the intact association was not apparent in the action spectrum. PMID:16661055

Global metabolic rewiring for improved CO2 fixation and chemical production in cyanobacteria.

PubMed

Kanno, Masahiro; Carroll, Austin L; Atsumi, Shota

2017-03-13

Cyanobacteria have attracted much attention as hosts to recycle CO 2 into valuable chemicals. Although cyanobacteria have been engineered to produce various compounds, production efficiencies are too low for commercialization. Here we engineer the carbon metabolism of Synechococcus elongatus PCC 7942 to improve glucose utilization, enhance CO 2 fixation and increase chemical production. We introduce modifications in glycolytic pathways and the Calvin Benson cycle to increase carbon flux and redirect it towards carbon fixation. The engineered strain efficiently uses both CO 2 and glucose, and produces 12.6 g l -1 of 2,3-butanediol with a rate of 1.1 g l -1  d -1 under continuous light conditions. Removal of native regulation enables carbon fixation and 2,3-butanediol production in the absence of light. This represents a significant step towards industrial viability and an excellent example of carbon metabolism plasticity.

Global metabolic rewiring for improved CO2 fixation and chemical production in cyanobacteria

NASA Astrophysics Data System (ADS)

Kanno, Masahiro; Carroll, Austin L.; Atsumi, Shota

2017-03-01

Cyanobacteria have attracted much attention as hosts to recycle CO2 into valuable chemicals. Although cyanobacteria have been engineered to produce various compounds, production efficiencies are too low for commercialization. Here we engineer the carbon metabolism of Synechococcus elongatus PCC 7942 to improve glucose utilization, enhance CO2 fixation and increase chemical production. We introduce modifications in glycolytic pathways and the Calvin Benson cycle to increase carbon flux and redirect it towards carbon fixation. The engineered strain efficiently uses both CO2 and glucose, and produces 12.6 g l-1 of 2,3-butanediol with a rate of 1.1 g l-1 d-1 under continuous light conditions. Removal of native regulation enables carbon fixation and 2,3-butanediol production in the absence of light. This represents a significant step towards industrial viability and an excellent example of carbon metabolism plasticity.

Physiological breeding.

PubMed

Reynolds, Matthew; Langridge, Peter

2016-06-01

Physiological breeding crosses parents with different complex but complementary traits to achieve cumulative gene action for yield, while selecting progeny using remote sensing, possibly in combination with genomic selection. Physiological approaches have already demonstrated significant genetic gains in Australia and several developing countries of the International Wheat Improvement Network. The techniques involved (see Graphical Abstract) also provide platforms for research and refinement of breeding methodologies. Recent examples of these include screening genetic resources for novel expression of Calvin cycle enzymes, identification of common genetic bases for heat and drought adaptation, and genetic dissection of trade-offs among yield components. Such information, combined with results from physiological crosses designed to test novel trait combinations, lead to more precise breeding strategies, and feed models of genotype-by-environment interaction to help build new plant types and experimental environments for future climates. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia: Mollusca).

PubMed

Cavanaugh, C M; Abbott, M S; Veenhuis, M

1988-10-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP(2)Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large subunit of RbuP(2)Case from tobacco (Nicotiana tabacum) cross-reacted on immunoblots with a protein of similar molecular mass occurring in extracts of the symbiont-containing gill tissue of S. velum. No cross-reactivity was detected in symbiont-free tissue extracts. The antiserum also cross-reacted in immunoblots with proteins of Thiobacillus neapolitanus, a free-living sulfuroxidizing chemoautotroph whose RbuP(2)Case has been well characterized. In protein A-gold immunoelectron microscopy studies, this antiserum consistently labeled the symbionts but not surrounding host gill tissue, indicating that the symbionts are responsible for the RbuP(2)Case activity.

Genetic engineering of Synechocystis PCC6803 for the photoautotrophic production of the sweetener erythritol.

PubMed

van der Woude, Aniek D; Perez Gallego, Ruth; Vreugdenhil, Angie; Puthan Veetil, Vinod; Chroumpi, Tania; Hellingwerf, Klaas J

2016-04-08

Erythritol is a polyol that is used in the food and beverage industry. Due to its non-caloric and non-cariogenic properties, the popularity of this sweetener is increasing. Large scale production of erythritol is currently based on conversion of glucose by selected fungi. In this study, we describe a biotechnological process to produce erythritol from light and CO2, using engineered Synechocystis sp. PCC6803. By functionally expressing codon-optimized genes encoding the erythrose-4-phosphate phosphatase TM1254 and the erythrose reductase Gcy1p, or GLD1, this cyanobacterium can directly convert the Calvin cycle intermediate erythrose-4-phosphate into erythritol via a two-step process and release the polyol sugar in the extracellular medium. Further modifications targeted enzyme expression and pathway intermediates. After several optimization steps, the best strain, SEP024, produced up to 2.1 mM (256 mg/l) erythritol, excreted in the medium.

Photosynthesis.

PubMed

Johnson, Matthew P

2016-10-31

Photosynthesis sustains virtually all life on planet Earth providing the oxygen we breathe and the food we eat; it forms the basis of global food chains and meets the majority of humankind's current energy needs through fossilized photosynthetic fuels. The process of photosynthesis in plants is based on two reactions that are carried out by separate parts of the chloroplast. The light reactions occur in the chloroplast thylakoid membrane and involve the splitting of water into oxygen, protons and electrons. The protons and electrons are then transferred through the thylakoid membrane to create the energy storage molecules adenosine triphosphate (ATP) and nicotinomide-adenine dinucleotide phosphate (NADPH). The ATP and NADPH are then utilized by the enzymes of the Calvin-Benson cycle (the dark reactions), which converts CO 2 into carbohydrate in the chloroplast stroma. The basic principles of solar energy capture, energy, electron and proton transfer and the biochemical basis of carbon fixation are explained and their significance is discussed. © 2016 The Author(s).

Arsenic metabolism in high altitude modern stromatolites revealed by metagenomic analysis.

PubMed

Kurth, Daniel; Amadio, Ariel; Ordoñez, Omar F; Albarracín, Virginia H; Gärtner, Wolfgang; Farías, María E

2017-04-21

Modern stromatolites thrive only in selected locations in the world. Socompa Lake, located in the Andean plateau at 3570 masl, is one of the numerous extreme Andean microbial ecosystems described over recent years. Extreme environmental conditions include hypersalinity, high UV incidence, and high arsenic content, among others. After Socompa's stromatolite microbial communities were analysed by metagenomic DNA sequencing, taxonomic classification showed dominance of Proteobacteria, Bacteroidetes and Firmicutes, and a remarkably high number of unclassified sequences. A functional analysis indicated that carbon fixation might occur not only by the Calvin-Benson cycle, but also through alternative pathways such as the reverse TCA cycle, and the reductive acetyl-CoA pathway. Deltaproteobacteria were involved both in sulfate reduction and nitrogen fixation. Significant differences were found when comparing the Socompa stromatolite metagenome to the Shark Bay (Australia) smooth mat metagenome: namely, those involving stress related processes, particularly, arsenic resistance. An in-depth analysis revealed a surprisingly diverse metabolism comprising all known types of As resistance and energy generating pathways. While the ars operon was the main mechanism, an important abundance of arsM genes was observed in selected phyla. The data resulting from this work will prove a cornerstone for further studies on this rare microbial community.

Effects of overexpressing photosynthetic carbon flux control enzymes in the cyanobacterium Synechocystis PCC 6803.

PubMed

Liang, Feiyan; Lindblad, Peter

2016-11-01

Synechocystis PCC 6803 is a model unicellular cyanobacterium used in e.g. photosynthesis and CO 2 assimilation research. In the present study we examined the effects of overexpressing Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), sedoheptulose 1,7-biphosphatase (SBPase), fructose-bisphosphate aldolase (FBA) and transketolase (TK), confirmed carbon flux control enzymes of the Calvin-Bassham-Benson (CBB) cycle in higher plants, in Synechocystis PCC 6803. Overexpressing RuBisCO, SBPase and FBA resulted in increased in vivo oxygen evolution (maximal 115%), growth rate and biomass accumulation (maximal 52%) under 100μmolphotonsm -2 s -1 light condition. Cells overexpressing TK showed a chlorotic phenotype but increased biomass by approximately 42% under 100μmolphotonsm -2 s -1 light condition. Under 15μmolphotonsm -2 s -1 light condition, cells overexpressing TK showed enhanced in vivo oxygen evolution. This study demonstrates increased growth and biomass accumulation when overexpressing selected enzymes of the CBB cycle. RuBisCO, SBPase, FBA and TK are identified as four potential targets to improve growth and subsequently also yield of valuable products from Synechocystis PCC 6803. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Unravelling the shape and structural assembly of the photosynthetic GAPDH-CP12-PRK complex from Arabidopsis thaliana by small-angle X-ray scattering analysis.

PubMed

Del Giudice, Alessandra; Pavel, Nicolae Viorel; Galantini, Luciano; Falini, Giuseppe; Trost, Paolo; Fermani, Simona; Sparla, Francesca

2015-12-01

Oxygenic photosynthetic organisms produce sugars through the Calvin-Benson cycle, a metabolism that is tightly linked to the light reactions of photosynthesis and is regulated by different mechanisms, including the formation of protein complexes. Two enzymes of the cycle, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK), form a supramolecular complex with the regulatory protein CP12 with the formula (GAPDH-CP122-PRK)2, in which both enzyme activities are transiently inhibited during the night. Small-angle X-ray scattering analysis performed on both the GAPDH-CP12-PRK complex and its components, GAPDH-CP12 and PRK, from Arabidopsis thaliana showed that (i) PRK has an elongated, bent and screwed shape, (ii) the oxidized N-terminal region of CP12 that is not embedded in the GAPDH-CP12 complex prefers a compact conformation and (iii) the interaction of PRK with the N-terminal region of CP12 favours the approach of two GAPDH tetramers. The interaction between the GAPDH tetramers may contribute to the overall stabilization of the GAPDH-CP12-PRK complex, the structure of which is presented here for the first time.

Isotopically Nonstationary Metabolic Flux Analysis (INST-MFA) of Photosynthesis and Photorespiration in Plants.

PubMed

Ma, Fangfang; Jazmin, Lara J; Young, Jamey D; Allen, Doug K

2017-01-01

Photorespiration is a central component of photosynthesis; however to better understand its role it should be viewed in the context of an integrated metabolic network rather than a series of individual reactions that operate independently. Isotopically nonstationary 13 C metabolic flux analysis (INST-MFA), which is based on transient labeling studies at metabolic steady state, offers a comprehensive platform to quantify plant central metabolism. In this chapter, we describe the application of INST-MFA to investigate metabolism in leaves. Leaves are an autotrophic tissue, assimilating CO 2 over a diurnal period implying that the metabolic steady state is limited to less than 12 h and thus requiring an INST-MFA approach. This strategy results in a comprehensive unified description of photorespiration, Calvin cycle, sucrose and starch synthesis, tricarboxylic acid (TCA) cycle, and amino acid biosynthetic fluxes. We present protocols of the experimental aspects for labeling studies: transient 13 CO 2 labeling of leaf tissue, sample quenching and extraction, mass spectrometry (MS) analysis of isotopic labeling data, measurement of sucrose and amino acids in vascular exudates, and provide details on the computational flux estimation using INST-MFA.

Absence of residual structure in the intrinsically disordered regulatory protein CP12 in its reduced state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Launay, Hélène; Barré, Patrick; Puppo, Carine

2016-08-12

The redox switch protein CP12 is a key player of the regulation of the Benson–Calvin cycle. Its oxidation state is controlled by the formation/dissociation of two intramolecular disulphide bridges during the day/night cycle. CP12 was known to be globally intrinsically disordered on a large scale in its reduced state, while being partly ordered in the oxidised state. By combining Nuclear Magnetic Resonance and Small Angle X-ray Scattering experiments, we showed that, contrary to secondary structure or disorder predictions, reduced CP12 is fully disordered, with no transient or local residual structure likely to be precursor of the structures identified in themore » oxidised active state and/or in the bound state with GAPDH or PRK. These results highlight the diversity of the mechanisms of regulation of conditionally disordered redox switches, and question the stability of oxidised CP12 scaffold. - Highlights: • CP12 is predicted to form two helices in its N-terminal sequence. • Reduced CP12 is disordered as a random coil according to SAXS. • Limited or no transient structures are observed in reduced CP12 by NMR.« less

Combined Inoculation with Multiple Arbuscular Mycorrhizal Fungi Improves Growth, Nutrient Uptake and Photosynthesis in Cucumber Seedlings.

PubMed

Chen, Shuangchen; Zhao, Hongjiao; Zou, Chenchen; Li, Yongsheng; Chen, Yifei; Wang, Zhonghong; Jiang, Yan; Liu, Airong; Zhao, Puyan; Wang, Mengmeng; Ahammed, Golam J

2017-01-01

Mycorrhizal inoculation stimulates growth, photosynthesis and nutrient uptake in a wide range of host plants. However, the ultimate effects of arbuscular mycorrhyzal (AM) symbiosis vary with the plants and fungal species involved in the association. Therefore, identification of the appropriate combinations of AM fungi (AMF) that interact synergistically to improve their benefits is of high significance. Here, three AM fungal compositions namely VT ( Claroideoglomus sp., Funneliformis sp., Diversispora sp., Glomus sp., and Rhizophagus sp.) and BF ( Glomus intraradices , G. microageregatum BEG and G. Claroideum BEG 210), and Funneliformis mosseae (Fm) were investigated with respect to the growth, gas exchange parameters, enzymes activities in Calvin cycles and related gene expression in cucumber seedlings. The results showed that VT, BF and Fm could successfully colonize cucumber root to a different degree with the colonization rates 82.38, 74.65, and 70.32% at 46 days post inoculation, respectively. The plant height, stem diameter, dry weight, root to shoot ratio of cucumber seedlings inoculated with AMF increased significantly compared with the non-inoculated control. Moreover, AMF colonization greatly increased the root activity, chlorophyll content, net photosynthetic rate, light saturated rate of the CO 2 assimilation ( A sat), maximum carboxylation rate ( V cmax ) and maximum ribulose-1,5-bis-phosphate (RuBP) regeneration rate ( J max), which were increased by 52.81, 30.75, 58.76, 47.00, 69.15, and 65.53% when inoculated with VT, respectively. The activities of some key enzymes such RuBP carboxylase/oxygenase (RuBisCO), D-fructose-1,6-bisphosphatase (FBPase), D-fructose-6-phosphatase (F6P) and ribulose-5-phosphate kinase (Ru5PK), and related gene expression involved in the Calvin cycle including RCA , FBPase , FBPA , SBPase , rbcS and rbcL were upregulated by AMF colonization. AMF inoculation also improved macro- and micro nutrient contents such as N, P, K, S, Ca, Cu, Fe, Mn, Mg, and Zn in roots. Further analysis revealed that inoculation with VT had relatively better effect on growth of cucumber seedling followed by BF and Fm, indicating that AMF composition consisting of distant AMF species may have a better effect than a single or closely related AMF spp. This study advances the understanding of plant responses to different AM fungi toward development of strategies on AMF-promoted vegetable production.

Appropriate NH4+: NO3- ratio improves low light tolerance of mini Chinese cabbage seedlings.

PubMed

Hu, Linli; Liao, Weibiao; Dawuda, Mohammed Mujitaba; Yu, Jihua; Lv, Jian

2017-01-23

In northwest of China, mini Chinese cabbage (Brassica pekinensis) is highly valued by consumers, and is widely cultivated during winter in solar-greenhouses where low light (LL) fluence (between 85 and 150 μmol m -2 s -1 in day) is a major abiotic stress factor limiting plant growth and crop productivity. The mechanisms with which various NH 4 + : NO 3 - ratios affected growth and photosynthesis of mini Chinese cabbage under normal (200 μmol m -2 s -1 ) and low (100 μmol m -2 s -1 ) light conditions was investigated. The four solutions with different ratios of NH 4 + : NO 3 - applied were 0:100, 10:90, 15:85 and 25:75 with the set up in a glasshouse in hydroponic culture. The most appropriate NH 4 + : NO 3 - ratio that improved the tolerance of mini Chinese cabbage seedlings to LL was found in our current study. Under low light, the application of NH 4 + : NO 3 - (10:90) significantly stimulated growth compared to only NO 3 - by increasing leaf area, canopy spread, biomass accumulation, and net photosynthetic rate. The increase in net photosynthetic rate was associated with an increase in: 1) maximum and effective quantum yield of PSII; 2) activities of Calvin cycle enzymes; and 3) levels of mRNA relative expression of several genes involved in Calvin cycle. In addition, glucose, fructose, sucrose, starch and total carbohydrate, which are the products of CO 2 assimilation, accumulated most in the cabbage leaves that were supplied with NH 4 + : NO 3 - (10:90) under LL condition. Low light reduced the carbohydrate: nitrogen (C: N) ratio while the application of NH 4 + : NO 3 - (10:90) alleviated the negative effect of LL on C: N ratio mainly by increasing total carbohydrate contents. The application of NH 4 + :NO 3 - (10:90) increased rbcL, rbcS, FBA, FBPase and TK expression and/or activities, enhanced photosynthesis, carbohydrate accumulation and improved the tolerance of mini Chinese cabbage seedlings to LL. The results of this study would provide theoretical basis and technical guidance for mini Chinese cabbage production. In practical production, the ratio of NH 4 + :NO 3 - should be adjusted with respect to light fluence for successful growing of mini Chinese cabbage.

Cyanobacterial-based approaches to improving photosynthesis in plants.

PubMed

Zarzycki, Jan; Axen, Seth D; Kinney, James N; Kerfeld, Cheryl A

2013-01-01

Plants rely on the Calvin-Benson (CB) cycle for CO(2) fixation. The key carboxylase of the CB cycle is ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Efforts to enhance carbon fixation in plants have traditionally focused on RubisCO or on approaches that can help to remedy RubisCO's undesirable traits: its low catalytic efficiency and photorespiration. Towards reaching the goal of improving plant photosynthesis, cyanobacteria may be instrumental. Because of their evolutionary relationship to chloroplasts, they represent ideal model organisms for photosynthesis research. Furthermore, the molecular understanding of cyanobacterial carbon fixation provides a rich source of strategies that can be exploited for the bioengineering of chloroplasts. These strategies include the cyanobacterial carbon concentrating mechanism (CCM), which consists of active and passive transporter systems for inorganic carbon and a specialized organelle, the carboxysome. The carboxysome encapsulates RubisCO together with carbonic anhydrase in a protein shell, resulting in an elevated CO(2) concentration around RubisCO. Moreover, cyanobacteria differ from plants in the isoenzymes involved in the CB cycle and the photorespiratory pathways as well as in mechanisms that can affect the activity of RubisCO. In addition, newly available cyanobacterial genome sequence data from the CyanoGEBA project, which has more than doubled the amount of genomic information available for cyanobacteria, increases our knowledge on the CCM and the occurrence and distribution of genes of interest.

THE WEBER THESIS OF CALVINISM AND CAPITALISM--ITS VARIOUS VERSIONS AND THEIR "FATE" IN SOCIAL SCIENCE.

PubMed

Zafirovski, Milan

2016-01-01

The paper identifies and examines various multiple renditions of the so-called Weber Thesis of an historical association and convergence between ascetic Protestantism, above all Calvinism, and the emergence and development of modern capitalism as an economic spirit and system. Specifically, it detects at least four different versions and formulations or interpretations, thus casting doubt in the common view of the Weber Thesis as a single and monolithic theory or hypothesis. The paper also considers the status of the multiple versions of the Weber Thesis in post-Weberian and contemporary sociology and related disciplines like economics and history. It concludes that the weaker, relaxed renditions of the Weber Thesis have attained a greater success and more endured in contemporary social science than have its stronger, stricter versions. © 2015 Wiley Periodicals, Inc.

Cyanobacterial carbon metabolism: Fluxome plasticity and oxygen dependence: Cyanobacterial Carbon Metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, Ni; DeLorenzo, Drew M.; He, Lian

Synechocystis sp. strain PCC 6803 has been widely used as a photo-biorefinery chassis. Based on its genome annotation, this species contains a complete TCA cycle, an Embden-Meyerhof-Parnas pathway (EMPP), an oxidative pentose phosphate pathway (OPPP), and an Entner–Doudoroff pathway (EDP). To evaluate how Synechocystis 6803 catabolizes glucose under heterotrophic conditions, we performed 13C metabolic flux analysis, metabolite pool size analysis, gene knockouts, and heterologous expressions. The results revealed a cyclic mode of flux through the OPPP. Small, but non-zero, fluxes were observed through the TCA cycle and the malic shunt. Independent knockouts of 6-phosphogluconate dehydrogenase (gnd) and malic enzyme (me)more » corroborated these results, as neither mutant could grow under dark heterotrophic conditions. Our data also indicate that Synechocystis 6803 metabolism relies upon oxidative phosphorylation to generate ATP from NADPH under dark or insufficient light conditions. The pool sizes of intermediates in the TCA cycle, particularly acetyl-CoA, were found to be several fold lower in Synechocystis 6803 (compared to E. coli metabolite pool sizes), while its sugar phosphate intermediates were several-fold higher. Moreover, negligible flux was detected through the native, or heterologous, EDP in the wild type or Δgnd strains under heterotrophic conditions. Comparing photoautotrophic, photomixotrophic, and heterotrophic conditions, the Calvin cycle, OPPP, and EMPP in Synechocystis 6803 possess the ability to regulate their fluxes under various growth conditions (plastic), whereas its TCA cycle always maintains at low levels (rigid). This work also demonstrates how genetic profiles do not always reflect actual metabolic flux through native or heterologous pathways. Biotechnol. Bioeng. 2017;114: 1593–1602. © 2017 Wiley Periodicals, Inc.« less

Melvin Calvin award lecture, Isotopic chemistry: the most varied of careers…with tritium and deuterium the most versatile of the isotopes.

PubMed

Lockley, William J S

2013-01-01

Isotopic chemistry offers the opportunity for organic chemists to explore a surprisingly large variety of scientific avenues. It lends itself naturally to multidisciplinary research projects and provides the sophisticated tools with which the most complex of processes can be investigated. This Melvin Calvin Award lecture will keep to a broadly chronological theme and will give examples of how the remarkable versatility of the two heavy hydrogen isotopes has been utilised during collaborative studies in areas as varied as plant and insect biochemistry, drug metabolism and pharmacokinetics, structure determination, NMR spectroscopy, reaction mechanisms, molecular energetics and novel catalyst development. Few other careers can provide the opportunity to study such varied and fundamental subjects and still provide challenges that are as compelling and exciting some 4 decades later. Copyright © 2013 John Wiley & Sons, Ltd.

Ralph Cudworth and the theological origins of consciousness.

PubMed

Carter, Benjamin

2010-01-01

The English Neoplatonic philosopher Ralph Cudworth introduced the term "consciousness" into the English philosophical lexicon. Cudworth uses the term to define the form and structure of cognitive acts, including acts of freewill. In this article I highlight the important role of theological disputes over the place and extent of human freewill within an overarching system of providence. Cudworth's intellectual development can be understood in the main as an increasingly detailed and nuanced reaction to the strict voluntarist Calvinism that is typified in the thought of his near contemporary William Perkins. At the heart of Cudworth's rejection of Calvinism is the dilemma over whether God is understood primarily in terms of will or justice. In this fleshing-out of the power of consciousness Cudworth moves from an instrumental account of the working of the human mind towards an account of human consciousness that is intrinsic to his definition of human agency.

A "footprint" of plant carbon fixation cycle functions during the development of a heterotrophic fungus.

PubMed

Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

2015-08-11

Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution.

System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium

PubMed Central

Lee, Do Yup; Park, Jeong-Jin; Barupal, Dinesh K.; Fiehn, Oliver

2012-01-01

Drastic alterations in macronutrients are known to cause large changes in biochemistry and gene expression in the photosynthetic alga Chlamydomonas reinhardtii. However, metabolomic and proteomic responses to subtle reductions in macronutrients have not yet been studied. When ammonium levels were reduced by 25–100% compared with control cultures, ammonium uptake and growth rates were not affected at 25% or 50% nitrogen-reduction for 28 h. However, primary metabolism and enzyme expression showed remarkable changes at acute conditions (4 h and 10 h after ammonium reduction) compared with chronic conditions (18 h and 28 h time points). Responses of 145 identified metabolites were quantified using gas chromatography-time of flight mass spectrometry; 495 proteins (including 187 enzymes) were monitored using liquid chromatography-ion trap mass spectrometry with label-free spectral counting. Stress response and carbon assimilation processes (Calvin cycle, acetate uptake and chlorophyll biosynthesis) were altered first, in addition to increase in enzyme contents for lipid biosynthesis and accumulation of short chain free fatty acids. Nitrogen/carbon balance metabolism was found changed only under chronic conditions, for example in the citric acid cycle and amino acid metabolism. Metabolism in Chlamydomonas readily responds to total available media nitrogen with temporal increases in short-chain free fatty acids and turnover of internal proteins, long before nitrogen resources are depleted. PMID:22787274

Persulfidation proteome reveals the regulation of protein function by hydrogen sulfide in diverse biological processes in Arabidopsis.

PubMed

Aroca, Angeles; Benito, Juan M; Gotor, Cecilia; Romero, Luis C

2017-10-13

Hydrogen sulfide-mediated signaling pathways regulate many physiological and pathophysiological processes in mammalian and plant systems. The molecular mechanism by which hydrogen sulfide exerts its action involves the post-translational modification of cysteine residues to form a persulfidated thiol motif, a process called protein persulfidation. We have developed a comparative and quantitative proteomic analysis approach for the detection of endogenous persulfidated proteins in wild-type Arabidopsis and L-CYSTEINE DESULFHYDRASE 1 mutant leaves using the tag-switch method. The 2015 identified persulfidated proteins were isolated from plants grown under controlled conditions, and therefore, at least 5% of the entire Arabidopsis proteome may undergo persulfidation under baseline conditions. Bioinformatic analysis revealed that persulfidated cysteines participate in a wide range of biological functions, regulating important processes such as carbon metabolism, plant responses to abiotic and biotic stresses, plant growth and development, and RNA translation. Quantitative analysis in both genetic backgrounds reveals that protein persulfidation is mainly involved in primary metabolic pathways such as the tricarboxylic acid cycle, glycolysis, and the Calvin cycle, suggesting that this protein modification is a new regulatory component in these pathways. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Global Metabolic Regulation of the Snow Alga Chlamydomonas nivalis in Response to Nitrate or Phosphate Deprivation by a Metabolome Profile Analysis.

PubMed

Lu, Na; Chen, Jun-Hui; Wei, Dong; Chen, Feng; Chen, Gu

2016-05-10

In the present work, Chlamydomonas nivalis, a model species of snow algae, was used to illustrate the metabolic regulation mechanism of microalgae under nutrient deprivation stress. The seed culture was inoculated into the medium without nitrate or phosphate to reveal the cell responses by a metabolome profile analysis using gas chromatography time-of-flight mass spectrometry (GC/TOF-MS). One hundred and seventy-one of the identified metabolites clustered into five groups by the orthogonal partial least squares discriminant analysis (OPLS-DA) model. Among them, thirty of the metabolites in the nitrate-deprived group and thirty-nine of the metabolites in the phosphate-deprived group were selected and identified as "responding biomarkers" by this metabolomic approach. A significant change in the abundance of biomarkers indicated that the enhanced biosynthesis of carbohydrates and fatty acids coupled with the decreased biosynthesis of amino acids, N-compounds and organic acids in all the stress groups. The up- or down-regulation of these biomarkers in the metabolic network provides new insights into the global metabolic regulation and internal relationships within amino acid and fatty acid synthesis, glycolysis, the tricarboxylic acid cycle (TCA) and the Calvin cycle in the snow alga under nitrate or phosphate deprivation stress.

Microbial communities and their predicted metabolic characteristics in deep fracture groundwaters of the crystalline bedrock at Olkiluoto, Finland

NASA Astrophysics Data System (ADS)

Bomberg, Malin; Lamminmäki, Tiina; Itävaara, Merja

2016-11-01

The microbial diversity in oligotrophic isolated crystalline Fennoscandian Shield bedrock fracture groundwaters is high, but the core community has not been identified. Here we characterized the bacterial and archaeal communities in 12 water conductive fractures situated at depths between 296 and 798 m by high throughput amplicon sequencing using the Illumina HiSeq platform. Between 1.7 × 104 and 1.2 × 106 bacterial or archaeal sequence reads per sample were obtained. These sequences revealed that up to 95 and 99 % of the bacterial and archaeal sequences obtained from the 12 samples, respectively, belonged to only a few common species, i.e. the core microbiome. However, the remaining rare microbiome contained over 3- and 6-fold more bacterial and archaeal taxa. The metabolic properties of the microbial communities were predicted using PICRUSt. The approximate estimation showed that the metabolic pathways commonly included fermentation, fatty acid oxidation, glycolysis/gluconeogenesis, oxidative phosphorylation, and methanogenesis/anaerobic methane oxidation, but carbon fixation through the Calvin cycle, reductive TCA cycle, and the Wood-Ljungdahl pathway was also predicted. The rare microbiome is an unlimited source of genomic functionality in all ecosystems. It may consist of remnants of microbial communities prevailing in earlier environmental conditions, but could also be induced again if changes in their living conditions occur.

Whole-cell response to nitrogen deprivation in the diatom Phaeodactylum tricornutum.

PubMed

Alipanah, Leila; Rohloff, Jens; Winge, Per; Bones, Atle M; Brembu, Tore

2015-10-01

Algal growth is strongly affected by nitrogen (N) availability. Diatoms, an ecologically important group of unicellular algae, have evolved several acclimation mechanisms to cope with N deprivation. In this study, we integrated physiological data with transcriptional and metabolite data to reveal molecular and metabolic modifications in N-deprived conditions in the marine diatom Phaeodactylum tricornutum. Physiological and metabolite measurements indicated that the photosynthetic capacity and chlorophyll content of the cells decreased, while neutral lipids increased in N-deprived cultures. Global gene expression analysis showed that P. tricornutum responded to N deprivation through an increase in N transport, assimilation, and utilization of organic N resources. Following N deprivation, reduced biosynthesis and increased recycling of N compounds like amino acids, proteins, and nucleic acids was observed at the transcript level. The majority of the genes associated with photosynthesis and chlorophyll biosynthesis were also repressed. Carbon metabolism was restructured through downregulation of the Calvin cycle and chrysolaminarin biosynthesis, and co-ordinated upregulation of glycolysis, the tricarboxylic acid cycle, and pyruvate metabolism, leading to funnelling of carbon sources to lipid metabolism. Finally, reallocation of membrane lipids and induction of de novo triacylglycerol biosynthesis directed cells to accumulation of neutral lipids. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

High CO2 subsurface environment enriches for novel microbial lineages capable of autotrophic carbon fixation

NASA Astrophysics Data System (ADS)

Probst, A. J.; Jerett, J.; Castelle, C. J.; Thomas, B. C.; Sharon, I.; Brown, C. T.; Anantharaman, K.; Emerson, J. B.; Hernsdorf, A. W.; Amano, Y.; Suzuki, Y.; Tringe, S. G.; Woyke, T.; Banfield, J. F.

2015-12-01

Subsurface environments span the planet but remain little understood from the perspective of the capacity of the resident organisms to fix CO2. Here we investigated the autotrophic capacity of microbial communities in range of a high-CO2 subsurface environments via analysis of 250 near-complete microbial genomes (151 of them from distinct species) that represent the most abundant organisms over a subsurface depth transect. More than one third of the genomes belonged to the so-called candidate phyla radiation (CPR), which have limited metabolic capabilities. Approximately 30% of the community members are autotrophs that comprise 70% of the microbiome with metabolism likely supported by sulfur and nitrogen respiration. Of the carbon fixation pathways, the Calvin Benson Basham Cycle was most common, but the Wood-Ljungdhal pathway was present in the greatest phylogenetic diversity of organisms. Unexpectedly, one organism from a novel phylum sibling to the CPR is predicted to fix carbon by the reverse TCA cycle. The genome of the most abundant organism, an archaeon designated "Candidatus Altiarchaeum hamiconexum", was also found in subsurface samples from other continents including Europe and Asia. The archaeon was proven to be a carbon fixer using a novel reductive acetyl-CoA pathway. These results provide evidence that carbon dioxide is the major carbon source in these environments and suggest that autotrophy in the subsurface represents a substantial carbon dioxide sink affecting the global carbon cycle.

Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions.

PubMed

Driever, Steven M; Simkin, Andrew J; Alotaibi, Saqer; Fisk, Stuart J; Madgwick, Pippa J; Sparks, Caroline A; Jones, Huw D; Lawson, Tracy; Parry, Martin A J; Raines, Christine A

2017-09-26

To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regard to future strategies for further improvement of photosynthesis in wheat.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Authors.

Artificial photosynthesis for production of hydrogen peroxide and its fuel cells.

PubMed

Fukuzumi, Shunichi

2016-05-01

The reducing power released from photosystem I (PSI) via ferredoxin enables the reduction of NADP(+) to NADPH, which is essential in the Calvin-Benson cycle to make sugars in photosynthesis. Alternatively, PSI can reduce O2 to produce hydrogen peroxide as a fuel. This article describes the artificial version of the photocatalytic production of hydrogen peroxide from water and O2 using solar energy. Hydrogen peroxide is used as a fuel in hydrogen peroxide fuel cells to make electricity. The combination of the photocatalytic H2O2 production from water and O2 using solar energy with one-compartment H2O2 fuel cells provides on-site production and usage of H2O2 as a more useful and promising solar fuel than hydrogen. This article is part of a Special Issue entitled Biodesign for Bioenergetics--The design and engineering of electronc transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016 Elsevier B.V. All rights reserved.

[Effect of cultivation conditions on the growth and activities of sulfur metabolism enzymes and carboxylases of Sulfobacillus thermosulfidooxidans subsp. asporogenes strain 41].

PubMed

Egorova, M A; Tsaplina, I A; Zakharchuk, L M; Bogdanova, T I; Krasil'nikova, E N

2004-01-01

The moderately thermophilic acidophilic bacterium Sulfobacillus thermosulfidooxidans subsp. asporogenes strain 41 is capable of utilizing sulfides of gold-arsenic concentrate and elemental sulfur as a source of energy. The growth in the presence of S0 under auto- or mixotrophic conditions was less stable compared with the media containing iron monoxide. The enzymes involved in oxidation of sulfur inorganic compounds--thiosulfate-oxidizing enzyme, tetrathionate hydrolase, rhodonase, adenylyl sulfate reductase, sulfite oxidase, and sulfur oxygenase--were discovered in the cells of Sulfobacillus grown in the mineral medium containing 0.02% yeast extract and either sulfur or iron monoxide and thiosulfate. Cell-free extracts of the cultures grown in the medium with sulfur under auto- or mixotrophic conditions displayed activity of the key enzyme of the Calvin cycle--ribulose bisphosphate carboxylase--and several other enzymes involved in heterotrophic fixation of carbonic acid. Activities of carboxylases depended on the composition of cultivation media.

Evolving Methanococcoides burtonii archaeal Rubisco for improved photosynthesis and plant growth

PubMed Central

Wilson, Robert H.; Alonso, Hernan; Whitney, Spencer M.

2016-01-01

In photosynthesis Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the often rate limiting CO2-fixation step in the Calvin cycle. This makes Rubisco both the gatekeeper for carbon entry into the biosphere and a target for functional improvement to enhance photosynthesis and plant growth. Encumbering the catalytic performance of Rubisco is its highly conserved, complex catalytic chemistry. Accordingly, traditional efforts to enhance Rubisco catalysis using protracted “trial and error” protein engineering approaches have met with limited success. Here we demonstrate the versatility of high throughput directed (laboratory) protein evolution for improving the carboxylation properties of a non-photosynthetic Rubisco from the archaea Methanococcoides burtonii. Using chloroplast transformation in the model plant Nicotiana tabacum (tobacco) we confirm the improved forms of M. burtonii Rubisco increased photosynthesis and growth relative to tobacco controls producing wild-type M. burtonii Rubisco. Our findings indicate continued directed evolution of archaeal Rubisco offers new potential for enhancing leaf photosynthesis and plant growth. PMID:26926260

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eckert, C. A.; Sullivan, R.; Johnson, C.

CO2 and H2 are promising feedstocks for production of valuable biocompounds. Ralstonia eutropha utilizes these feedstocks to generate energy (ATP) and reductant (NAD(P)H) via oxidation of H2 by a membrane-bound (MBH) and a soluble hydrogenase (SH) for CO2 fixation by the Calvin-Benson-Bassham (CBB) cycle. Increased expression of the enzyme that fixes CO2 (RubisCO) resulted in 6-fold activity improvement in vitro, while increased expression of the MBH operon or the SH operon plus MBH operon maturation factors necessary for activity resulted in a 10-fold enhancement. Current research involves genetic manipulation of two endogenous cbb operons for increased expression, analysis of expressionmore » and activity of CBB/MBH/SH, cofactor ratios, and downstream products during autotrophic growth in control versus enhanced strains, and development of strategies for long-term, optimal overexpression. These studies will improve our understanding of autotrophic metabolism and provide a chassis strain for autotrophic production of biodiesel and other valuable carbon biocompounds.« less

Evolving Methanococcoides burtonii archaeal Rubisco for improved photosynthesis and plant growth.

PubMed

Wilson, Robert H; Alonso, Hernan; Whitney, Spencer M

2016-03-01

In photosynthesis Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the often rate limiting CO2-fixation step in the Calvin cycle. This makes Rubisco both the gatekeeper for carbon entry into the biosphere and a target for functional improvement to enhance photosynthesis and plant growth. Encumbering the catalytic performance of Rubisco is its highly conserved, complex catalytic chemistry. Accordingly, traditional efforts to enhance Rubisco catalysis using protracted "trial and error" protein engineering approaches have met with limited success. Here we demonstrate the versatility of high throughput directed (laboratory) protein evolution for improving the carboxylation properties of a non-photosynthetic Rubisco from the archaea Methanococcoides burtonii. Using chloroplast transformation in the model plant Nicotiana tabacum (tobacco) we confirm the improved forms of M. burtonii Rubisco increased photosynthesis and growth relative to tobacco controls producing wild-type M. burtonii Rubisco. Our findings indicate continued directed evolution of archaeal Rubisco offers new potential for enhancing leaf photosynthesis and plant growth.

FRET analysis of CP12 structural interplay by GAPDH and PRK.

PubMed

Moparthi, Satish Babu; Thieulin-Pardo, Gabriel; de Torres, Juan; Ghenuche, Petru; Gontero, Brigitte; Wenger, Jérôme

2015-03-13

CP12 is an intrinsically disordered protein playing a key role in the regulation of the Benson-Calvin cycle. Due to the high intrinsic flexibility of CP12, it is essential to consider its structural modulation induced upon binding to the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) enzymes. Here, we report for the first time detailed structural modulation about the wild-type CP12 and its site-specific N-terminal and C-terminal disulfide bridge mutants upon interaction with GAPDH and PRK by Förster resonance energy transfer (FRET). Our results indicate an increase in CP12 compactness when the complex is formed with GAPDH or PRK. In addition, the distributions in FRET histograms show the elasticity and conformational flexibility of CP12 in all supra molecular complexes. Contrarily to previous beliefs, our FRET results importantly reveal that both N-terminal and C-terminal site-specific CP12 mutants are able to form the monomeric (GAPDH-CP12-PRK) complex. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural kinetic modeling of metabolic networks.

PubMed

Steuer, Ralf; Gross, Thilo; Selbig, Joachim; Blasius, Bernd

2006-08-08

To develop and investigate detailed mathematical models of metabolic processes is one of the primary challenges in systems biology. However, despite considerable advance in the topological analysis of metabolic networks, kinetic modeling is still often severely hampered by inadequate knowledge of the enzyme-kinetic rate laws and their associated parameter values. Here we propose a method that aims to give a quantitative account of the dynamical capabilities of a metabolic system, without requiring any explicit information about the functional form of the rate equations. Our approach is based on constructing a local linear model at each point in parameter space, such that each element of the model is either directly experimentally accessible or amenable to a straightforward biochemical interpretation. This ensemble of local linear models, encompassing all possible explicit kinetic models, then allows for a statistical exploration of the comprehensive parameter space. The method is exemplified on two paradigmatic metabolic systems: the glycolytic pathway of yeast and a realistic-scale representation of the photosynthetic Calvin cycle.

Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations

NASA Technical Reports Server (NTRS)

Madigan, M. T.; Takigiku, R.; Lee, R. G.; Gest, H.; Hayes, J. M.

1989-01-01

Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacteriochlorophyll from photoautotrophically grown cultures of C. tepidum yielded 13C fractionation factors near -20%. Cells of C. tepidum grown on excess acetate, wherein synthesis of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase ribulose bisphosphate carboxylase) was greatly repressed, were isotopically heavier, fractionation factors of ca. -7% being observed. Fractionation factors determined by isotopic analyses of cells and pigment fractions of natural populations of C. tepidum growing in three different sulfide thermal springs in Yellowstone National Park were approximately -20%, indicating that this purple sulfur bacterium grows as a photoautotroph in nature.

Learning's Professional Reading for Teachers.

ERIC Educational Resources Information Center

Ohanian, Susan

1982-01-01

A "Learning" magazine editor recommends five books for teachers: (1) "Hunger of Memory" (Richard Rodriguez); (2) "Cushla and Her Books" (Dorothy Butler); (3) "Uncivil Liberties" (Calvin Trillin); (4) "Selected Letters of James Thurber"; and (5) "The Selected Letters of Mark Twain." A…

Molecular Signatures of Microbial Metabolism in an Actively Growing, Silicified, Microbial Structure from Yellowstone National Park

NASA Astrophysics Data System (ADS)

Ferreira, M.; Creveling, J.; Hilburn, I.; Karlsson, E.; Pepe-Ranney, C.; Spear, J.; Dawson, S.; Geobio2008, I.

2008-12-01

Silicified structures that exhibit a putative biologic component in their formation permeate the rock record as stromatolites. We have studied a silicified microbial structure from a hot spring in Yellowstone National Park using phenotypic, phylogenetic, and metagenomic analyses to determine microbial carbon metabolic pathways and the phylogenetic affiliations of microbes present in this unique structure. In this multi-faceted approach, dominant physiologies, specifically with regards to anaerobic and aerobic metabolisms, were inferred from 16S rRNA gene sequences and 454 sequencing data from bulk DNA samples of the structure. Carbon utilization as indicated by ECO Biolog plates showed abundant heterotrophy and heterotrophic diversity throughout the microbial structure. Microbes within the structure are able to utilize all tested sources of carbohydrates, lipids/fatty acids, and protein/amino acids as carbon sources. ECO plate testing of the hot spring water yielded considerable less carbohydrate consumption (only 4 out of 13 tested carbohydrates) and similar lipids/fatty acids and protein/amino acids consumption (2 out of 3 and 5 out of 5 tested sources respectively). Full length 16S rRNA gene sequences and metagenomic 454 pyrosequencing of community DNA showed limited diversity among primary producers. From the 16S data, the majority of the autotrophs are inferred to utilize the Calvin cycle for CO2 fixation, followed by 3-hydroxypropionate/4- hydroxybutyrate CO2 fixation. However, an analysis of the metagenomic data compared to the KEGG database does not show genes directly involved with Calvin cycle carbon fixation. Further BLAST searches of our data failed to find significant matches within our 6514 metagenomic sequences to known RuBisCo sequences taken from the NCBI database. This is likely due to a far under-sampled dataset of metagenomic sequences, and the low number (958) that had matches to the KEGG pathways database. Anaerobic versus aerobic physiology also can be estimated from the 16S clone libraries. Phylogenetic analysis of recovered 16S sequences suggests that 15% of the 16S sequences can be attributed to anaerobic microbes while 42% likely come from aerobes. The remaining 43% of 16S rRNA gene sequences belong to metabolically unassigned phyla both known and novel. This preliminary study demonstrates that the small spatially stratified silicified microbial structure present on the margins of a hot spring contains a rich and complex microbial community with different trophic levels and enzymatic pathways.

Field test of coordinated ramp metering (CRM).

DOT National Transportation Integrated Search

2017-03-15

This project has focused on field implementation and testing of a Coordinated Ramp Metering (CRM) algorithm at California State Route 99 : Northbound corridor in Sacramento between Calvine Road and the SR50 interchange after 12th Ave. It is a 9 mile ...

77 FR 70537 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... A. Giarrusso (FL) Benjamin P. Hall (NY) John N. Lanning (CA) Bruce J. Lewis (RI) John L. Lolley (AL) Charles M. McDaris (GA) Tommy L. McKnight (OH) Calvin J. Schaap (MN) Frederick C. Schultz, Jr. (NY) Steve...

Calvin Mukarakate | NREL

Science.gov Websites

for the Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products. He is also a ;Unimolecular Thermal Decomposition of Dimethoxybenzenes," Journal of Chemical Physics (2014) "Real ," Green Chemistry (2014) "Biomass Pyrolysis: Thermal Decomposition Mechanisms of Furfural and

Black Newspapers: Neglected Source for the "New South."

ERIC Educational Resources Information Center

Beatty, Bess

1980-01-01

Examines the political climate and popular Black opinion in the late nineteenth century South through the writings of six Black southern newspaper editors (Pinckney Benton Stewart Pinchback, Charles Hendley, W. Calvin Chase, John Mitchell, Jr., William Pledger, and John Willis Menard). (GC)

Tips from the Classroom.

ERIC Educational Resources Information Center

TESOL Journal, 1993

1993-01-01

Four short articles are combined: "Adding Discourse-Level Practice to Sentence-Level Exercises" (Eric S. Nelson); "Presenting Picture Books in the ESL Classroom" (Lijun Shen); "Role Playing in a Large Class" (Ellen Rosen); and "Calvin and Hobbes and Other Icons of Americana" (Daniel J. Conrad). (Contains seven references.) (LB)

Calvin A. Henard | NREL

Science.gov Websites

years of postdoctoral training at the University of Texas Medical Branch in Galveston, Texas, evaluating transcriptional regulation Redox signaling Education Ph.D., Microbiology, University of Colorado Anschutz Medical Postdoctoral Scholar, University of Texas Medical Branch, 2012-2014 Graduate Student Fellow, University of

The effects of environmental physical factors on the microbial communities and the distribution of different CO2 fixation pathways in a limestone landscape

NASA Astrophysics Data System (ADS)

Wun, S. R.; Huang, T. Y.; Hsu, B. M.; Fan, C. W.

2017-12-01

We aimed to study the effects of physical factors on the relative abundance of bacteria and their preferential admissions of autotrophic CO2 fixation pathways after subjected to environmental long-term influence. The Narrow-Sky located in upper part of Takangshan is a small gulch of Pleistocene coralline limestone formation in southern Taiwan. The physical parameters such as illumination, humidity, and temperature were varied largely in habitats around the gulch, namely on the limestone wall at the opening of gulch, on the coordinate ground soil, on the wall inside the gulch, and the water drip from limestone wall. The total organic carbon was measured in solid samples to evaluate the biomass of the habitats. A metagenomic approach was carried out to reveal their microbial community structure. After the metagenomic library of operational taxonomic units (OTUs) was constructed, a BLAST search by "nomenclature of bacteria" instead of sequences between the OTU libraries and KEGG database was carried out to generate libraries of "model microbial communities", which the complete genomes of the entire bacterial populations were available. Our results showed the biomass of habitats in the opening of gulch was twice higher than the inside, suggesting the illumination played an important role in biosynthesis. In quantitative comparison in key enzymes of CO2 fixation pathways by model communities, 70% to 90% of bacteria possessed key enzymes of Fuchs-Holo cycle, while only 5% to 20% of bacteria contained key enzymes of Calvin-Benson cycle. The key enzymes for hydroxypropionate/ hydroxybutyrate and dicarboxylate/ 4-hydroxybutyrate cycles were not found in this study. In the water sample, approximate 10% of bacteria consisted of the key enzyme for Arnon-Buchanan cycle. Less than 2% of bacteria in all habitats take the reductive acetyl-CoA cycle for CO2 fixation. This study provides a novel method to study biosynthetic process of microbial communities in natural habitats.

Proteomics of rice and Cochliobolus miyabeanus fungal interaction: insight into proteins at intracellular and extracellular spaces.

PubMed

Kim, Jin Yeong; Wu, Jingni; Kwon, Soon Jae; Oh, Haram; Lee, So Eui; Kim, Sang Gon; Wang, Yiming; Agrawal, Ganesh Kumar; Rakwal, Randeep; Kang, Kyu Young; Ahn, Il-Pyung; Kim, Beom-Gi; Kim, Sun Tae

2014-10-01

Necrotrophic fungal pathogen Cochliobolus miyabeanus causes brown spot disease in rice leaves upon infection, resulting in critical rice yield loss. To better understand the rice-C. miyabeanus interaction, we employed proteomic approaches to establish differential proteomes of total and secreted proteins from the inoculated leaves. The 2DE approach after PEG-fractionation of total proteins coupled with MS (MALDI-TOF/TOF and nESI-LC-MS/MS) analyses led to identification of 49 unique proteins out of 63 differential spots. SDS-PAGE in combination with nESI-LC-MS/MS shotgun approach was applied to identify secreted proteins in the leaf apoplast upon infection and resulted in cataloging of 501 unique proteins, of which 470 and 31 proteins were secreted from rice and C. miyabeanus, respectively. Proteins mapped onto metabolic pathways implied their reprogramming upon infection. The enzymes involved in Calvin cycle and glycolysis decreased in their protein abundance, whereas enzymes in the TCA cycle, amino acids, and ethylene biosynthesis increased. Differential proteomes also generated distribution of identified proteins in the intracellular and extracellular spaces, providing a better insight into defense responses of proteins in rice against C. miyabeanus. Established proteome of the rice-C. miyabeanus interaction serves not only as a good resource for the scientific community but also highlights its significance from biological aspects. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Art Education and Issues of Pornography.

ERIC Educational Resources Information Center

Blandy, Doug; Congdon, Kristin G.

1997-01-01

Briefly discusses some of the recent developments in the on-going controversy concerning pornography and the arts. Argues that much of the mainstream press coverage merely sensationalizes incidents (e.g., "Time" magazine's cover story on cyberporn and the furor over Calvin Klein advertisements) and encourages polarized opinions. (MJP)

It's just grass, isn't it?

USDA-ARS?s Scientific Manuscript database

The theme of the Calvin Sperling Memorial Lectureship is "biodiversity" specifically with regard to crop germplasm. Could any other theme be nearer to the heart and soul of a plant breeder or geneticist? In 40 years of working on crop germplasm biodiversity, I've (hopefully) learned some lessons abo...

Pathfinders: An Intellectual Guide to Libraries.

ERIC Educational Resources Information Center

Jung, Claudia Ruediger; And Others

Intended as an example for other college libraries, this collection of 38 pathfinders and bibliographies was developed by the reference staff of the Calvin Coolidge Library at Castleton State College, Vermont. Designed to present the types of literature available in particular subject fields and those works readily available in the Coolidge…

Finding Meaning in the Details

ERIC Educational Resources Information Center

Boyle, Sharon McKittrick

2011-01-01

In this article, the author describes an art project inspired by the work of the Canadian artist, Calvin Nicholls, who makes amazing low-relief sculptures from archival paper. Student works include owls in flight, a hawk, a kingfisher, a rat on a chain, a moth, and other creatures. (Contains 1 online resource.)

Leadership and Pedagogy: Rethinking Leadership in Professional Schools of Education.

ERIC Educational Resources Information Center

Marshall, J. Dan; And Others

1989-01-01

Analyzes cultural dimensions of Calvin College's Bridenthal Internship in Teaching program for improving the quality of public school teachers; explores how problems encountered by interns as classroom teachers relate to cultural dimensions of the program's industrial leadership orientation and style of leadership modeled by mentor John Wright.…

The Outlines of Political Theology in the Protestant Reformation.

ERIC Educational Resources Information Center

Cooper, John W.

1982-01-01

The ideas of Luther and Calvin challenged Catholicism and laid the foundation for the conventional American views on church-state relationships. Knowledge of the Protestant tradition in politics is a necessary requirement to an understanding of public life and of Western political culture since the Reformation. (RM)

Reference Collection Development Policy.

ERIC Educational Resources Information Center

Nebraska Univ., Kearney.

The purpose of this policy is to outline those principles that guide the development of the Reference Collection at the Calvin T. Ryan Library, University of Nebraska at Kearney. It clarifies, records, and makes public the basic principles that the members of the Reference Department believe should be applied in adding items to or withdrawing…

Teaching Biology for a Sustainable Future

ERIC Educational Resources Information Center

Musante, Susan

2011-01-01

Students at Calvin College in Grand Rapids, Michigan, can now take an innovative biology course in which an integrated, interdisciplinary, problem-based approach is used--one that the scientific community itself is promoting. The first course in a four-semester sequence, Biology 123--The Living World: Concepts and Connections--explores real-world…

The Evangelical Mind Revisited

ERIC Educational Resources Information Center

Wolfe, Alan

2006-01-01

On May 21, 2005, President George W. Bush delivered the commencement address at Calvin College in Grand Rapids, Michigan. As candidate and as president, George W. Bush had developed a reputation for paying close attention to the concerns of the conservative evangelical Protestants who cement his political base. Few institutions of higher learning…

DEVELOPMENT OF PROTEIN PROFILE TECHNOLOGY TO EVALUATE ECOLOGICAL EFFECTS OF ENVIRONMENTAL CHEMICALS USING A SMALL FISH MODEL

EPA Science Inventory

Hemmer, Michael J., Robert T. Hudson and Calvin C. Walker. In press. Development of Protein Profile Technology to Evaluate Ecological Effects of Environmental Chemicals Using a Small Fish Model (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosyste...

ACUTE AND CHRONIC TOXICITY OF BREVETOXIN TO OYSTERS AND GRASS SHRIMP

EPA Science Inventory

Walker, Calvin C., James T. Winstead, Steven S. Foss, Janis C. Kurtz, James Watts, Jeanne E. Scott and William S. Fisher. In press. Acute and Chronic Toxicity of Brevetoxin to Oysters and Grass Shrimp (Abstract). To be presented at the SETAC Fourth World Congress, 14-18 November ...

77 FR 37068 - Muzaffer Aslan, M.D.; Decision and Order

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-20

... DEPARTMENT OF JUSTICE Drug Enforcement Administration Muzaffer Aslan, M.D.; Decision and Order On... Cause and Immediate Suspension of Registration to Muzaffer Aslan, M.D. (hereinafter, Respondent), of Los....C. 824, of the CSA. Calvin Ramsey, 76 FR 20034, 20036 (2011) (other citations omitted); Brenton D...

77 FR 18862 - Zhiwei Lin, M.D.; Decision and Order

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

... DEPARTMENT OF JUSTICE Drug Enforcement Administration [Docket No. 10-54] Zhiwei Lin, M.D.; Decision and Order On September 19, 2011, Administrative Law Judge (ALJ) Timothy D. Wing issued the....C. 824, of the CSA. Calvin Ramsey, 76 FR 20034, 20036 (2011) (other citations omitted); Brenton D...

A resolution commending Louisiana jockey Calvin Borel for his victory in the 135th Kentucky Derby.

THOMAS, 111th Congress

Sen. Landrieu, Mary L. [D-LA

2009-05-05

Senate - 05/05/2009 Submitted in the Senate, considered, and agreed to without amendment and with a preamble by Unanimous Consent. (All Actions) Tracker: This bill has the status Agreed to in SenateHere are the steps for Status of Legislation:

Genome sequence of the ultrasmall unicellular red alga Cyanidioschyzon merolae 10D.

PubMed

Matsuzaki, Motomichi; Misumi, Osami; Shin-I, Tadasu; Maruyama, Shinichiro; Takahara, Manabu; Miyagishima, Shin-Ya; Mori, Toshiyuki; Nishida, Keiji; Yagisawa, Fumi; Nishida, Keishin; Yoshida, Yamato; Nishimura, Yoshiki; Nakao, Shunsuke; Kobayashi, Tamaki; Momoyama, Yu; Higashiyama, Tetsuya; Minoda, Ayumi; Sano, Masako; Nomoto, Hisayo; Oishi, Kazuko; Hayashi, Hiroko; Ohta, Fumiko; Nishizaka, Satoko; Haga, Shinobu; Miura, Sachiko; Morishita, Tomomi; Kabeya, Yukihiro; Terasawa, Kimihiro; Suzuki, Yutaka; Ishii, Yasuyuki; Asakawa, Shuichi; Takano, Hiroyoshi; Ohta, Niji; Kuroiwa, Haruko; Tanaka, Kan; Shimizu, Nobuyoshi; Sugano, Sumio; Sato, Naoki; Nozaki, Hisayoshi; Ogasawara, Naotake; Kohara, Yuji; Kuroiwa, Tsuneyoshi

2004-04-08

Small, compact genomes of ultrasmall unicellular algae provide information on the basic and essential genes that support the lives of photosynthetic eukaryotes, including higher plants. Here we report the 16,520,305-base-pair sequence of the 20 chromosomes of the unicellular red alga Cyanidioschyzon merolae 10D as the first complete algal genome. We identified 5,331 genes in total, of which at least 86.3% were expressed. Unique characteristics of this genomic structure include: a lack of introns in all but 26 genes; only three copies of ribosomal DNA units that maintain the nucleolus; and two dynamin genes that are involved only in the division of mitochondria and plastids. The conserved mosaic origin of Calvin cycle enzymes in this red alga and in green plants supports the hypothesis of the existence of single primary plastid endosymbiosis. The lack of a myosin gene, in addition to the unexpressed actin gene, suggests a simpler system of cytokinesis. These results indicate that the C. merolae genome provides a model system with a simple gene composition for studying the origin, evolution and fundamental mechanisms of eukaryotic cells.

A difference gel electrophoresis study on thylakoids isolated from poplar leaves reveals a negative impact of ozone exposure on membrane proteins.

PubMed

Bohler, Sacha; Sergeant, Kjell; Hoffmann, Lucien; Dizengremel, Pierre; Hausman, Jean-Francois; Renaut, Jenny; Jolivet, Yves

2011-07-01

Populus tremula L. x P. alba L. (Populus x canescens (Aiton) Smith), clone INRA 717-1-B4, saplings were subjected to 120 ppb ozone exposure for 28 days. Chloroplasts were isolated, and the membrane proteins, solubilized using the detergent 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC), were analyzed in a difference gel electrophoresis (DiGE) experiment comparing control versus ozone-exposed plants. Extrinsic photosystem (PS) proteins and adenosine triphosphatase (ATPase) subunits were detected to vary in abundance. The general trend was a decrease in abundance, except for ferredoxin-NADP(+) oxidoreductase (FNR), which increased after the first 7 days of exposure. The up-regulation of FNR would increase NAPDH production for reducing power and detoxification inside and outside of the chloroplast. Later on, FNR and a number of PS and ATPase subunits decrease in abundance. This could be the result of oxidative processes on chloroplast proteins but could also be a way to down-regulate photochemical reactions in response to an inhibition in Calvin cycle activity.

Purification of active chloroplast sedoheptulose-1,7-bisphosphatase expressed in Escherichia coli.

PubMed

Dunford, R P; Catley, M A; Raines, C A; Lloyd, J C; Dyer, T A

1998-10-01

Sedoheptulose-1,7-bisphosphatase (SBPase) is an enzyme unique to photosynthetic organisms and has a key role in regulating the photosynthetic Calvin cycle through which nearly all carbon enters the biosphere. This makes SBPase an appropriate target for intensive study. We have expressed wheat SBPase in Escherichia coli either with or without an N-terminal polyhistidine tag. The identity of the recombinant SBPases was confirmed by SDS-PAGE analysis and immunological detection with a specific antibody. Recombinant SBPase with a polyhistidine tag (His-SBPase) was obtained in soluble, active form and purified by one-step metal-chelate chromatography. Like the native enzyme, recombinant His-SBPase was specific for the substrate sedoheptulose-1,7-bisphosphate and required the presence of a reducing agent for activity. Polyclonal antibodies were raised against recombinant SBPase and were then used to determine relative levels of the enzyme in plant extracts. The availability of large amounts of active recombinant SBPase will also allow detailed structural studies by site-directed mutagenesis and X-ray crystallography. Copyright 1998 Academic Press.

Metabolic Adaptation in Transplastomic Plants Massively Accumulating Recombinant Proteins

PubMed Central

Bally, Julia; Job, Claudette; Belghazi, Maya; Job, Dominique

2011-01-01

Background Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. Methodology/Principal Findings Here we used proteomics to characterize tobacco (Nicotiana tabacum) plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD) or a green fluorescent protein (GFP). While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO2 metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. Conclusions/Significance The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation. PMID:21966485

Faster recovery of a diatom from UV damage under ocean acidification.

PubMed

Wu, Yaping; Campbell, Douglas A; Gao, Kunshan

2014-11-01

Diatoms are the most important group of primary producers in marine ecosystems. As oceanic pH declines and increased stratification leads to the upper mixing layer becoming shallower, diatoms are interactively affected by both lower pH and higher average exposures to solar ultraviolet radiation. The photochemical yields of a model diatom, Phaeodactylum tricornutum, were inhibited by ultraviolet radiation under both growth and excess light levels, while the functional absorbance cross sections of the remaining photosystem II increased. Cells grown under ocean acidification (OA) were less affected during UV exposure. The recovery of PSII under low photosynthetically active radiation was much faster than in the dark, indicating that photosynthetic processes were essential for the full recovery of photosystem II. This light dependent recovery required de novo synthesized protein. Cells grown under ocean acidification recovered faster, possibly attributable to higher CO₂ availability for the Calvin cycle producing more resources for repair. The lower UV inhibition combined with higher recovery rate under ocean acidification could benefit species such as P.tricornutum, and change their competitiveness in the future ocean. Copyright © 2014 Elsevier B.V. All rights reserved.

Network Analysis of Enzyme Activities and Metabolite Levels and Their Relationship to Biomass in a Large Panel of Arabidopsis Accessions[C][W][OA

PubMed Central

Sulpice, Ronan; Trenkamp, Sandra; Steinfath, Matthias; Usadel, Bjorn; Gibon, Yves; Witucka-Wall, Hanna; Pyl, Eva-Theresa; Tschoep, Hendrik; Steinhauser, Marie Caroline; Guenther, Manuela; Hoehne, Melanie; Rohwer, Johann M.; Altmann, Thomas; Fernie, Alisdair R.; Stitt, Mark

2010-01-01

Natural genetic diversity provides a powerful resource to investigate how networks respond to multiple simultaneous changes. In this work, we profile maximum catalytic activities of 37 enzymes from central metabolism and generate a matrix to investigate species-wide connectivity between metabolites, enzymes, and biomass. Most enzyme activities change in a highly coordinated manner, especially those in the Calvin-Benson cycle. Metabolites show coordinated changes in defined sectors of metabolism. Little connectivity was observed between maximum enzyme activities and metabolites, even after applying multivariate analysis methods. Measurements of posttranscriptional regulation will be required to relate these two functional levels. Individual enzyme activities correlate only weakly with biomass. However, when they are used to estimate protein abundances, and the latter are summed and expressed as a fraction of total protein, a significant positive correlation to biomass is observed. The correlation is additive to that obtained between starch and biomass. Thus, biomass is predicted by two independent integrative metabolic biomarkers: preferential investment in photosynthetic machinery and optimization of carbon use. PMID:20699391

Transcriptome-based analysis on carbon metabolism of Haematococcus pluvialis mutant under 15% CO2.

PubMed

Li, Ke; Cheng, Jun; Lu, Hongxiang; Yang, Weijuan; Zhou, Junhu; Cen, Kefa

2017-06-01

To elucidate the mechanism underlying the enhanced growth rate in the Haematococcus pluvialis mutated with 60 Co-γ rays and domesticated with 15% CO 2 , transcriptome sequencing was conducted to clarify the carbon metabolic pathways of mutant cells. The CO 2 fixation rate of mutant cells increased to 2.57gL -1 d -1 under 15% CO 2 due to the enhanced photosynthesis, carbon fixation, glycolysis pathways. The upregulation of PetH, ATPF0A and PetJ related to photosynthetic electron transport, ATP synthase and NADPH generation promoted the photosynthesis. The upregulation of genes related to Calvin cycle and ppdK promoted carbon fixation in both C3 and C4 photosynthetic pathways. The reallocation of carbon was also enhanced under 15% CO 2 . The 19-, 14- and 3.5-fold upregulation of FBA, TPI and PK genes, respectively, remarkably promoted the glycolysis pathways. This accelerated the conversion of photosynthetic carbon to pyruvate, which was an essential precursor for astaxanthin and lipids biosynthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Global transcriptomic profiling of aspen trees under elevated [CO2] to identify potential molecular mechanisms responsible for enhanced radial growth.

PubMed

Wei, Hairong; Gou, Jiqing; Yordanov, Yordan; Zhang, Huaxin; Thakur, Ramesh; Jones, Wendy; Burton, Andrew

2013-03-01

Aspen (Populus tremuloides) trees growing under elevated [CO(2)] at a free-air CO(2) enrichment (FACE) site produced significantly more biomass than control trees. We investigated the molecular mechanisms underlying the observed increase in biomass by producing transcriptomic profiles of the vascular cambium zone (VCZ) and leaves, and then performed a comparative study to identify significantly changed genes and pathways after 12 years exposure to elevated [CO(2)]. In leaves, elevated [CO(2)] enhanced expression of genes related to Calvin cycle activity and linked pathways. In the VCZ, the pathways involved in cell growth, cell division, hormone metabolism, and secondary cell wall formation were altered while auxin conjugation, ABA synthesis, and cytokinin glucosylation and degradation were inhibited. Similarly, the genes involved in hemicellulose and pectin biosynthesis were enhanced, but some genes that catalyze important steps in lignin biosynthesis pathway were inhibited. Evidence from systemic analysis supported the functioning of multiple molecular mechanisms that underpin the enhanced radial growth in response to elevated [CO(2)].

The Genome of Deep-Sea Vent Chemolithoautotroph Thiomicrospira crunogena XCL-2

PubMed Central

Scott, Kathleen M; Sievert, Stefan M; Abril, Fereniki N; Ball, Lois A; Barrett, Chantell J; Blake, Rodrigo A; Boller, Amanda J; Chain, Patrick S. G; Clark, Justine A; Davis, Carisa R; Detter, Chris; Do, Kimberly F; Dobrinski, Kimberly P; Faza, Brandon I; Fitzpatrick, Kelly A; Freyermuth, Sharyn K; Harmer, Tara L; Hauser, Loren J; Hügler, Michael; Kerfeld, Cheryl A; Klotz, Martin G; Kong, William W; Land, Miriam; Lapidus, Alla; Larimer, Frank W; Longo, Dana L; Lucas, Susan; Malfatti, Stephanie A; Massey, Steven E; Martin, Darlene D; McCuddin, Zoe; Meyer, Folker; Moore, Jessica L; Ocampo, Luis H; Paul, John H; Paulsen, Ian T; Reep, Douglas K; Ren, Qinghu; Ross, Rachel L; Sato, Priscila Y; Thomas, Phaedra; Tinkham, Lance E; Zeruth, Gary T

2006-01-01

Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 base pairs), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of coding sequences (CDSs) encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. Thiom. crunogena XCL-2 is unusual among obligate sulfur-oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome. PMID:17105352

Modeling the Metabolism of Arabidopsis thaliana: Application of Network Decomposition and Network Reduction in the Context of Petri Nets.

PubMed

Koch, Ina; Nöthen, Joachim; Schleiff, Enrico

2017-01-01

Motivation: Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. Nevertheless, the system is not yet fully understood, although many mechanisms are described, and information for many processes exists. However, the combination and interpretation of the large amount of biological data remain a big challenge, not only because data sets for metabolic paths are still incomplete. Moreover, they are often inconsistent, because they are coming from different experiments of various scales, regarding, for example, accuracy and/or significance. Here, theoretical modeling is powerful to formulate hypotheses for pathways and the dynamics of the metabolism, even if the biological data are incomplete. To develop reliable mathematical models they have to be proven for consistency. This is still a challenging task because many verification techniques fail already for middle-sized models. Consequently, new methods, like decomposition methods or reduction approaches, are developed to circumvent this problem. Methods: We present a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana . We used the Petri net formalism to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency we applied concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs. Results: We formulated the core metabolism of Arabidopsis thaliana based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism. By applying network decomposition and reduction techniques at steady-state conditions, we suggest a straightforward mathematical modeling process. We demonstrate that potential steady-state pathways exist, which provide the fixed carbon to nearly all parts of the network, especially to the citric acid cycle. There is a close cooperation of important metabolic pathways, e.g., the de novo synthesis of uridine-5-monophosphate, the γ-aminobutyric acid shunt, and the urea cycle. The presented approach extends the established methods for a feasible interpretation of biological network models, in particular of large and complex models.

Modeling the Metabolism of Arabidopsis thaliana: Application of Network Decomposition and Network Reduction in the Context of Petri Nets

PubMed Central

Koch, Ina; Nöthen, Joachim; Schleiff, Enrico

2017-01-01

Motivation: Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. Nevertheless, the system is not yet fully understood, although many mechanisms are described, and information for many processes exists. However, the combination and interpretation of the large amount of biological data remain a big challenge, not only because data sets for metabolic paths are still incomplete. Moreover, they are often inconsistent, because they are coming from different experiments of various scales, regarding, for example, accuracy and/or significance. Here, theoretical modeling is powerful to formulate hypotheses for pathways and the dynamics of the metabolism, even if the biological data are incomplete. To develop reliable mathematical models they have to be proven for consistency. This is still a challenging task because many verification techniques fail already for middle-sized models. Consequently, new methods, like decomposition methods or reduction approaches, are developed to circumvent this problem. Methods: We present a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. We used the Petri net formalism to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency we applied concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs. Results: We formulated the core metabolism of Arabidopsis thaliana based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism. By applying network decomposition and reduction techniques at steady-state conditions, we suggest a straightforward mathematical modeling process. We demonstrate that potential steady-state pathways exist, which provide the fixed carbon to nearly all parts of the network, especially to the citric acid cycle. There is a close cooperation of important metabolic pathways, e.g., the de novo synthesis of uridine-5-monophosphate, the γ-aminobutyric acid shunt, and the urea cycle. The presented approach extends the established methods for a feasible interpretation of biological network models, in particular of large and complex models. PMID:28713420

Patents – Melvin Calvin

Science.gov Websites

plutonium from uranium and fission products in an aqueous acidic solution by use of a chelating agent. The concentration is adjusted to about 1 N bar. The aqueous solution is then contacted with a water-immiscible organic solvent solution and the chelating agent. The chelating agents covered by this invention comprise

Visualization of lunar excavation test in NASA Glenn's GRUVE Lab

NASA Image and Video Library

1969-12-31

Calvin Robinson of NASA Glenn's GVIS Team demonstrates a visualization of an excavation test conducted at NASA Glenn Research Center's SLOPE Lab ( https://rt.grc.nasa.gov/main/rlc/simu... ) . The visualization shows the flow of a lunar soil simulant as it flows in and past a proposed excavation bucket.

77 FR 56262 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-12

... (IL) Calvin D. Bills (VA) Joel W. Bryant (LA) Jonathan E. Carriaga (NM) Curtis E. Firari (WI) Percy L. Gaston (TX) Ronald M. Green (OH) Charles S. Huffman (KS) Richard Iocolano (NY) Daniel W. Johnson (NY) Charles R. Murphy (TX) Danny W. Nuckles (VA) Charles E. Queen (OH) Matias P. Quintanilla (CA) The...

The University of Mississippi Studies in English (1990), New Series Volume VIII.

ERIC Educational Resources Information Center

Fisher, Benjamin Franklin, IV, Ed.

This book, a new series in literary criticism and English studies, presents 24 essays. Essays in the book are: "Melville and the Question of Camoes" (George Monteiro); "Calvin Daniel Yost, Jr." (Benjamin Franklin Fisher IV); "'The Haystack in the Floods': An Uncharacteristic Preraphaelite Poem" (Veronica M. S.…

Free at Last

ERIC Educational Resources Information Center

Demski, Jennifer

2009-01-01

When superintendent Calvin Baker of the Vail School District in Vail, Arizona, substituted laptops for textbooks in Vail's first 1-to-1 high school in 2005, he saw that his district now had the freedom to purchase digital content the way he purchased digital music. "People would say, "So, what digital textbook are you going to use?"…

Curriculum Materials for Use with Grades K-12: A Bibliography of Government Documents.

ERIC Educational Resources Information Center

Keith, Diana J., Comp.

The Government Documents Collection of the Calvin T. Ryan Library of the University of Nebraska at Kearney contains a broad range of information on a variety of topics, including curriculum guides and materials. This bibliography gathers government documents of special interest to education students, practicing teachers, and teachers of adult…

Curriculum Materials for Use with Adult Groups: A Bibliography of Government Documents.

ERIC Educational Resources Information Center

Keith, Diana J., Comp.

The Government Documents Collection of the Calvin T. Ryan Library of the University of Nebraska at Kearney contains a broad range of information on a variety of topics, including curriculum guides and materials. This bibliography gathers government documents of special interest to education students, practicing teachers, and teachers of adult…

The Talents Dovetail: Initiative for Identifying Gifted and Talented Minority Students.

ERIC Educational Resources Information Center

Talents Unlimited, Inc., Mobile, AL.

The Talents Unlimited (TU) critical and creative thinking skills model is designed to help teachers recognize and nurture the multiple talents of all children. Research based on the work of Calvin Taylor, has identified high-level talent areas of productive thinking, communication, forecasting, decision making, and planning, in which all excel to…

Of Horses and Men: Superintendent Asbury's Deadly Assault on the Crow.

ERIC Educational Resources Information Center

McCleary, Carrie Moran

2003-01-01

Discusses Superintendent Calvin Asbury's campaign to convert members of the Crow Tribe to Christianity. Presents Joe Medicine Crow, who was a child during the campaign that began in 1919, as he describes the historical and continuing effects on the Tribe. Explains that federal policy included selling tribal lands to non-Indians, prohibiting…

Rejecting Dialogue for Perspective: Vygotsky's Zone of Proximal Development and John Calvin's Divine Pedagogy

ERIC Educational Resources Information Center

Horner, Jeffrey Michael

2017-01-01

James Estep's integration of Vygotsky's work on the Zone of Proximal Development into Christian education and pedagogy falls short of a distinctly evangelical form of integration. Using Ken Badley's schemata of Integration of Faith and Learning, this article distinguishes Estep's "paradigmatic" integration from a more thoroughgoing…

PLASMA PROTEIN PROFILING AS A HIGH THROUGHPUT TOOL FOR CHEMICAL SCREENING USING A SMALL FISH MODEL

EPA Science Inventory

Hudson, R. Tod, Michael J. Hemmer, Kimberly A. Salinas, Sherry S. Wilkinson, James Watts, James T. Winstead, Peggy S. Harris, Amy Kirkpatrick and Calvin C. Walker. In press. Plasma Protein Profiling as a High Throughput Tool for Chemical Screening Using a Small Fish Model (Abstra...

Sulfide oxidation, nitrate respiration, carbon acquisition, and electron transport pathways suggested by the draft genome of a single orange Guaymas Basin Beggiatoa (Cand. Maribeggiatoa) sp. filament.

PubMed

MacGregor, Barbara J; Biddle, Jennifer F; Harbort, Christopher; Matthysse, Ann G; Teske, Andreas

2013-09-01

A near-complete draft genome has been obtained for a single vacuolated orange Beggiatoa (Cand. Maribeggiatoa) filament from a Guaymas Basin seafloor microbial mat, the third relatively complete sequence for the Beggiatoaceae. Possible pathways for sulfide oxidation; nitrate respiration; inorganic carbon fixation by both Type II RuBisCO and the reductive tricarboxylic acid cycle; acetate and possibly formate uptake; and energy-generating electron transport via both oxidative phosphorylation and the Rnf complex are discussed here. A role in nitrite reduction is suggested for an abundant orange cytochrome produced by the Guaymas strain; this has a possible homolog in Beggiatoa (Cand. Isobeggiatoa) sp. PS, isolated from marine harbor sediment, but not Beggiatoa alba B18LD, isolated from a freshwater rice field ditch. Inferred phylogenies for the Calvin-Benson-Bassham (CBB) cycle and the reductive (rTCA) and oxidative (TCA) tricarboxylic acid cycles suggest that genes encoding succinate dehydrogenase and enzymes for carboxylation and/or decarboxylation steps (including RuBisCO) may have been introduced to (or exported from) one or more of the three genomes by horizontal transfer, sometimes by different routes. Sequences from the two marine strains are generally more similar to each other than to sequences from the freshwater strain, except in the case of RuBisCO: only the Guaymas strain encodes a Type II enzyme, which (where studied) discriminates less against oxygen than do Type I RuBisCOs. Genes subject to horizontal transfer may represent key steps for adaptation to factors such as oxygen and carbon dioxide concentration, organic carbon availability, and environmental variability. © 2013.

Unicellular cyanobacteria with a new mode of life: the lack of photosynthetic oxygen evolution allows nitrogen fixation to proceed.

PubMed

Bothe, Hermann; Tripp, H James; Zehr, Jonathan P

2010-10-01

Some unicellular N(2)-fixing cyanobacteria have recently been found to lack a functional photosystem II of photosynthesis. Such organisms, provisionally termed UCYN-A, of the oceanic picoplanktion are major contributors to the global marine N-input by N(2)-fixation. Since their photosystem II is inactive, they can perform N(2)-fixation during the day. UCYN-A organisms cannot be cultivated as yet. Their genomic analysis indicates that they lack genes coding for enzymes of the Calvin cycle, the tricarboxylic acid cycle and for the biosynthesis of several amino acids. The carbon source in the ocean that allows them to thrive in such high abundance has not been identified. Their genomic analysis implies that they metabolize organic carbon by a new mode of life. These unicellular N(2)-fixing cyanobacteria of the oceanic picoplankton are evolutionarily related to spheroid bodies present in diatoms of the family Epithemiaceae, such as Rhopalodia gibba. More recently, spheroid bodies were ultimately proven to be related to cyanobacteria and to express nitrogenase. They have been reported to be completely inactive in all photosynthetic reactions despite the presence of thylakoids. Sequence data show that R. gibba and its spheroid bodies are an evolutionarily young symbiosis that might serve as a model system to unravel early events in the evolution of chloroplasts. The cell metabolism of UCYN-A and the spheroid bodies may be related to that of the acetate photoassimilating green alga Chlamydobotrys.

Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops.

PubMed

Sharwood, Robert E

2017-01-01

494 I. 495 II. 496 III. 496 IV. 499 V. 499 VI. 501 VII. 501 VIII. 502 IX. 505 X. 506 507 References 507 SUMMARY: The uncertainty of future climate change is placing pressure on cropping systems to continue to provide stable increases in productive yields. To mitigate future climates and the increasing threats against global food security, new solutions to manipulate photosynthesis are required. This review explores the current efforts available to improve carbon assimilation within plant chloroplasts by engineering Rubisco, which catalyzes the rate-limiting step of CO 2 fixation. Fixation of CO 2 and subsequent cycling of 3-phosphoglycerate through the Calvin cycle provides the necessary carbohydrate building blocks for maintaining plant growth and yield, but has to compete with Rubisco oxygenation, which results in photorespiration that is energetically wasteful for plants. Engineering improvements in Rubisco is a complex challenge and requires an understanding of chloroplast gene regulatory pathways, and the intricate nature of Rubisco catalysis and biogenesis, to transplant more efficient forms of Rubisco into crops. In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L-subunit responsible for improvements in catalysis. Improving the capacity of CO 2 fixation in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis. © 2016 The Author. New Phytologist © 2016 New Phytologist Trust.

First Comparative Analysis of the Community Structures and Carbon Metabolic Pathways of the Bacteria Associated with Alvinocaris longirostris in a Hydrothermal Vent of Okinawa Trough.

PubMed

Sun, Qing-Lei; Zeng, Zhi-Gang; Chen, Shuai; Sun, Li

2016-01-01

Alvinocaris longirostris is a species of shrimp existing in the hydrothermal fields of Okinawa Trough. To date the structure and function of the microbial community associated with A. longirostris are essentially unknown. In this study, by employment of the techniques of high through-put sequencing and clone library construction and analysis, we compared for the first time the community structures and metabolic profiles of microbes associated with the gill and gut of A. longirostris in a hydrothermal field of Okinawa Trough. Fourteen phyla were detected in the gill and gut communities, of which 11 phyla were shared by both tissues. Proteobacteria made up a substantial proportion in both tissues, while Firmicutes was abundant only in gut. Although gill and gut communities were similar in bacterial diversities, the bacterial community structures in these two tissues were significantly different. Further, we discovered for the first time the existence in the gill and gut communities of A. longirostris the genes (cbbM and aclB) encoding the key enzymes of Calvin-Benson-Bassham (CBB) cycle and the reductive tricarboxylic acid (rTCA) cycle, and that both cbbM and aclB were significantly more abundant in gill than in gut. Taken together, these results provide the first evidence that at least two carbon fixation pathways are present in both the gill and the gut communities of A. longirostris, and that the communities in different tissues likely differ in autotrophic productivity.

Nonlinear dynamics of the CAM circadian rhythm in response to environmental forcing.

PubMed

Hartzell, Samantha; Bartlett, Mark S; Virgin, Lawrence; Porporato, Amilcare

2015-03-07

Crassulacean acid metabolism (CAM) photosynthesis functions as an endogenous circadian rhythm coupled to external environmental forcings of energy and water availability. This paper explores the nonlinear dynamics of a new CAM photosynthesis model (Bartlett et al., 2014) and investigates the responses of CAM plant carbon assimilation to different combinations of environmental conditions. The CAM model (Bartlett et al., 2014) consists of a Calvin cycle typical of C3 plants coupled to an oscillator of the type employed in the Van der Pol and FitzHugh-Nagumo systems. This coupled system is a function of environmental variables including leaf temperature, leaf moisture potential, and irradiance. Here, we explore the qualitative response of the system and the expected carbon assimilation under constant and periodically forced environmental conditions. The model results show how the diurnal evolution of these variables entrains the CAM cycle with prevailing environmental conditions. While constant environmental conditions generate either steady-state or periodically oscillating responses in malic acid uptake and release, forcing the CAM system with periodic daily fluctuations in light exposure and leaf temperature results in quasi-periodicity and possible chaos for certain ranges of these variables. This analysis is a first step in quantifying changes in CAM plant productivity with variables such as the mean temperature, daily temperature range, irradiance, and leaf moisture potential. Results may also be used to inform model parametrization based on the observed fluctuating regime. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

PubMed Central

Levicán, Gloria; Ugalde, Juan A; Ehrenfeld, Nicole; Maass, Alejandro; Parada, Pilar

2008-01-01

Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms. PMID:19055775

Ferredoxin:thioredoxin reductase (FTR) links the regulation of oxygenic photosynthesis to deeply rooted bacteria.

PubMed

Balsera, Monica; Uberegui, Estefania; Susanti, Dwi; Schmitz, Ruth A; Mukhopadhyay, Biswarup; Schürmann, Peter; Buchanan, Bob B

2013-02-01

Uncovered in studies on photosynthesis 35 years ago, redox regulation has been extended to all types of living cells. We understand a great deal about the occurrence, function, and mechanism of action of this mode of regulation, but we know little about its origin and its evolution. To help fill this gap, we have taken advantage of available genome sequences that make it possible to trace the phylogenetic roots of members of the system that was originally described for chloroplasts-ferredoxin, ferredoxin:thioredoxin reductase (FTR), and thioredoxin as well as target enzymes. The results suggest that: (1) the catalytic subunit, FTRc, originated in deeply rooted microaerophilic, chemoautotrophic bacteria where it appears to function in regulating CO(2) fixation by the reverse citric acid cycle; (2) FTRc was incorporated into oxygenic photosynthetic organisms without significant structural change except for addition of a variable subunit (FTRv) seemingly to protect the Fe-S cluster against oxygen; (3) new Trxs and target enzymes were systematically added as evolution proceeded from bacteria through the different types of oxygenic photosynthetic organisms; (4) an oxygenic type of regulation preceded classical light-dark regulation in the regulation of enzymes of CO(2) fixation by the Calvin-Benson cycle; (5) FTR is not universally present in oxygenic photosynthetic organisms, and in certain early representatives is seemingly functionally replaced by NADP-thioredoxin reductase; and (6) FTRc underwent structural diversification to meet the ecological needs of a variety of bacteria and archaea.

With a Little Help from My Friends (and Mark Twain Too) Musings and Farewells

ERIC Educational Resources Information Center

Graham, Steve

2010-01-01

Over the years, the author has drawn on a variety of friends, both fictional and real, to help him make specific points when writing professional papers and books for teachers, administrators, and researchers. This included Snoopy and other Peanut characters to describe how struggling writers compose; Calvin and his imaginary tiger Hobbes to…

"Moral Philosophy and Curricular Reform": Catharine Beecher and Nineteenth-Century Educational Leadership for Women

ERIC Educational Resources Information Center

Lewis, Gladys S.

2009-01-01

Catharine Beecher, daughter of Lyman Beecher and reared in New England Calvinism, struggled against it as a means of acquiring life orientation. Convinced of the mind's superiority in resolving moral and ethical matters, she developed pioneering views on women's education with its three linchpins, which became known as moral philosophy: (1)…

Creating an Internal Content Management System

ERIC Educational Resources Information Center

Sennema, Greg

2004-01-01

In this article, the author talks about an internal content management system that they have created at Calvin College. It is a hybrid of CMS and intranet that organizes Web site content and a variety of internal tools to help librarians complete their daily tasks. Hobbes is a Web-based tool that uses Common Gateway Interface (CGI) scripts written…

Listening to Community Voices: Community-Based Research, a First Step in Partnership and Outreach

ERIC Educational Resources Information Center

Heffner, Gail Gunst; Zandee, Gail Landheer; Schwander, Lissa

2003-01-01

This paper offers some historical perspective on alternative research traditions and discusses some of the basic principles of community-based research as a tool for partnership development. The authors then describe an example of how Calvin College, a Christian comprehensive liberal arts college has used a multi-disciplinary approach in…

Summer Conference on General Topology and Applications (10th) Held in Amsterdam on 15-18 August 1994

DTIC Science & Technology

1994-08-18

topology. Joint work by: I. Juhisz and Z. Szentmiid6ssy. Room: KC1.37 Time: TUE 16:40-1 7:00 ABSTRACTS 89 Forcing and Normality, II LUcia R. Junqueira...Gerard A. Venema (Calvin College, Grand Rapids, MI, USA) J. Vermeer (TU Delft, Delft, the Netherlands) Paolo Vitolo (Universita della Basilicata, Potenza

Mapping a Strategic Plan for Health: Community-Based Participatory Research with Underserved, Low-Income, Urban Neighborhoods

ERIC Educational Resources Information Center

Zandee, Gail

2012-01-01

Since 2002, community-based participatory research methods have been used by the Calvin College Nursing Department to map out a strategic health plan for three urban, low-income, underserved neighborhoods. Nine focus groups and 449 door-to-door health surveys were completed across the three urban neighborhoods between 2002 and 2004. Neighborhood…

Exploration of Integrated Visible to Near-, Shortwave-, and Longwave-Infrared (Full-Range) Spectral Analysis

DTIC Science & Technology

2014-09-01

4 Figure 2. The four fundamental energy interactions with matter (from Olsen, 2014). ..... 4 Figure 3. Comparison of Blackbody, Graybody...15 Figure 10. Mineral maps of Comstock mining district around Virginia City, Nevada (from Vaughan & Calvin...23 Figure 13. Comparison of SEBASS emissivity spectrum (hydrothermal silica, Cuprite, NV) and laboratory spectrum of quartz (JHU Minerals

Elements Required for an Efficient NADP-Malic Enzyme Type C4 Photosynthesis1[C][W][OPEN

PubMed Central

Wang, Yu; Long, Stephen P.; Zhu, Xin-Guang

2014-01-01

C4 photosynthesis has higher light, nitrogen, and water use efficiencies than C3 photosynthesis. Although the basic anatomical, cellular, and biochemical features of C4 photosynthesis are well understood, the quantitative significance of each element of C4 photosynthesis to the high photosynthetic efficiency are not well defined. Here, we addressed this question by developing and using a systems model of C4 photosynthesis, which includes not only the Calvin-Benson cycle, starch synthesis, sucrose synthesis, C4 shuttle, and CO2 leakage, but also photorespiration and metabolite transport between the bundle sheath cells and mesophyll cells. The model effectively simulated the CO2 uptake rates, and the changes of metabolite concentrations under varied CO2 and light levels. Analyses show that triose phosphate transport and CO2 leakage can help maintain a high photosynthetic rate by balancing ATP and NADPH amounts in bundle sheath cells and mesophyll cells. Finally, we used the model to define the optimal enzyme properties and a blueprint for C4 engineering. As such, this model provides a theoretical framework for guiding C4 engineering and studying C4 photosynthesis in general. PMID:24521879

Metabolic flexibility revealed in the genome of the cyst-forming α-1 proteobacterium Rhodospirillum centenum

PubMed Central

2010-01-01

Background Rhodospirillum centenum is a photosynthetic non-sulfur purple bacterium that favors growth in an anoxygenic, photosynthetic N2-fixing environment. It is emerging as a genetically amenable model organism for molecular genetic analysis of cyst formation, photosynthesis, phototaxis, and cellular development. Here, we present an analysis of the genome of this bacterium. Results R. centenum contains a singular circular chromosome of 4,355,548 base pairs in size harboring 4,105 genes. It has an intact Calvin cycle with two forms of Rubisco, as well as a gene encoding phosphoenolpyruvate carboxylase (PEPC) for mixotrophic CO2 fixation. This dual carbon-fixation system may be required for regulating internal carbon flux to facilitate bacterial nitrogen assimilation. Enzymatic reactions associated with arsenate and mercuric detoxification are rare or unique compared to other purple bacteria. Among numerous newly identified signal transduction proteins, of particular interest is a putative bacteriophytochrome that is phylogenetically distinct from a previously characterized R. centenum phytochrome, Ppr. Genes encoding proteins involved in chemotaxis as well as a sophisticated dual flagellar system have also been mapped. Conclusions Remarkable metabolic versatility and a superior capability for photoautotrophic carbon assimilation is evident in R. centenum. PMID:20500872

Engineering of chimeric eukaryotic/bacterial Rubisco large subunits in Escherichia coli.

PubMed

Koay, Teng Wei; Wong, Hann Ling; Lim, Boon Hoe

2016-11-26

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a rate-limiting photosynthetic enzyme that catalyzes carbon fixation in the Calvin cycle. Much interest has been devoted to engineering this ubiquitous enzyme with the goal of increasing plant growth. However, experiments that have successfully produced improved Rubisco variants, via directed evolution in Escherichia coli, are limited to bacterial Rubisco because the eukaryotic holoenzyme cannot be produced in E. coli. The present study attempts to determine the specific differences between bacterial and eukaryotic Rubisco large subunit primary structure that are responsible for preventing heterologous eukaryotic holoenzyme formation in E. coli. A series of chimeric Synechococcus Rubiscos were created in which different sections of the large subunit were swapped with those of the homologous Chlamydomonas Rubisco. Chimeric holoenzymes that can form in vivo would indicate that differences within the swapped sections do not disrupt holoenzyme formation. Large subunit residues 1-97, 198-247 and 448-472 were successfully swapped without inhibiting holoenzyme formation. In all ten chimeras, protein expression was observed for the separate subunits at a detectable level. As a first approximation, the regions that can tolerate swapping may be targets for future engineering.

Glycine decarboxylase is confined to the bundle-sheath cells of leaves of C3-C 4 intermediate species.

PubMed

Hylton, C M; Rawsthorne, S; Smith, A M; Jones, D A; Woolhouse, H W

1988-10-01

Immunogold labelling has been used to determine the cellular distribution of glycine decarboxylase in leaves of C3, C3-C4 intermediate and C4 species in the genera Moricandia, Panicum, Flaveria and Mollugo. In the C3 species Moricandia foleyi and Panicum laxum, glycine decarboxylase was present in the mitochondria of both mesophyll and bundle-sheath cells. However, in all the C3-C4 intermediate (M. arvensis var. garamatum, M. nitens, M. sinaica, M. spinosa, M. suffruticosa, P. milioides, Flaveria floridana, F. linearis, Mollugo verticillata) and C4 (P. prionitis, F. trinervia) species studied glycine decarboxylase was present in the mitochondria of only the bundle-sheath cells. The bundle-sheath cells of all the C3-C4 intermediate species have on their centripetal faces numerous mitochondria which are larger in profile area than those in mesophyll cells and are in close association with chloroplasts and peroxisomes. Confinement of glycine decarboxylase to the bundle-sheath cells is likely to improve the potential for recapture of photorespired CO2 via the Calvin cycle and could account for the low rate of photorespiration in all C3-C4 intermediate species.

[Molecular responses of photosynthetic apparatus of plants to long term irradiance changes].

PubMed

Adamiec, Małgorzata; Jackowski, Grzegorz

2008-01-01

In response to long term (at least 1-3 h) irradiance changes the responses are elicited at the level of structure and function of photosynthetic apparatus of plants which are thought to be aimed to keep the balance between the level of excitation energy funneled to the reaction centers of the photosystems by energetic antennae and the utilization of this energy in the form of photosynthetic electron transfer and dark reactions. At high vs medium irradiances the rate of excitation energy transfer via LHCII is reduced while the rate of electron flow and photosynthetic dark reactions is increased. The reaction at LHCII level stems from the reduction of its pool per PSII reaction center and the regulatory events comprise changes in the expression of LHCII apoproteins and/or chi b biosynthesis. The basis for higher electron flow capabilities lies in significant increases in the content of some electron carriers and the catalytic activity of ATP synthase. The upregulation of photosynthetic dark reaction in turn is due to the activation of signaling pathways leading to the increase in the pool and catalytic activities of rubisco and other Calvin cycle enzymes.

A novel method for determination of the (15) N isotopic composition of Rubisco in wheat plants exposed to elevated atmospheric carbon dioxide.

PubMed

Aranjuelo, Iker; Molero, Gemma; Avice, Jean Christophe; Bourguignon, Jacques

2015-02-01

Although ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is mostly known as a key enzyme involved in CO2 assimilation during the Calvin cycle, comparatively little is known about its role as a pool of nitrogen storage in leaves. For this purpose, we developed a protocol to purify Rubisco that enables later analysis of its (15) N isotope composition (δ(15) N) at the natural abundance and (15) N-labeled plants. In order to test the utility of this protocol, durum wheat (Triticum durum var. Sula) exposed to an elevated CO2 concentration (700 vs 400 µmol mol(-1) ) was labeled with K(15) NO3 (enriched at 2 atom %) during the ear development period. The developed protocol proves to be selective, simple, cost effective and reproducible. The study reveals that (15) N labeling was different in total organic matter, total soluble protein and the Rubisco fraction. The obtained data suggest that photosynthetic acclimation in wheat is caused by Rubisco depletion. This depletion may be linked to preferential nitrogen remobilization from Rubisco toward grain filling. © 2014 Scandinavian Plant Physiology Society.

Ecohydrology of the different photosynthetic pathways and implication for sustainable agriculture

NASA Astrophysics Data System (ADS)

Porporato, A. M.; Bartlett, M. S., Jr.; Hartzell, S. R.

2016-12-01

We use a recently proposed model that can simulate the different photosynthetic pathways coupled to the soil-plant-atmosphere continuum (SPAC) to discuss their ecohydrological implications in relation to water use and plant water stress in both natural and agricultural ecosystems. Built around the classical C3 photosynthesis core model (light reactions and Calvin cycle), the model includes a simple CO2-pump parameterization for C4 plants and a circadian rhythm and carbon storage components for the CAM (Crassulacean Acid Metabolism) plants. Its architecture takes advantage of the interesting modularity in which photosynthesis evolved in geological times to provide a relatively simple but comprehensive framework to explore the advantages and tradeoffs in water energy and carbon fluxes of the three photosynthetic pathways under fluctuating environmental forcing. We calibrate the model with reference to a series of C3,C4 and CAM plants, and discuss the trade-offs in water use and plan productivity and the related impact on hydrologic fluxes and soil biogeochemistry. We also consider some important crop species to analyze the implications of choosing crops with different photosynthetic pathways to improve sustainability of agriculture and irrigation in semiarid systems.

Unraveling the molecular mechanism of photosynthetic toxicity of highly fluorescent silver nanoclusters to Scenedesmus obliquus.

PubMed

Zhang, Li; Goswami, Nirmal; Xie, Jianping; Zhang, Bo; He, Yiliang

2017-11-27

While the discovery of numerous attractive properties of silver at the nanoscale has increased their demand in many sectors including medicine, optics, sensing, painting and cosmetics, it has also raised wide public concerns about their effect on living organisms in aquatic environment. Despite the continuous effort to understand the various aspects of the toxicity of silver nanomaterials, the molecular level understanding on their cytotoxicity mechanism to biological organisms has remained unclear. Herein, we demonstrated the underlying mechanism of the photosynthetic toxicity against green algae namely, Scenedesmus obliquus by using an emerging silver nanomaterial, called silver nanoclusters (defined as r-Ag NCs). By exploiting the unique fluorescence properties of r-Ag NCs along with various other analytical/biological tools, we proposed that the photosynthetic toxicity of r-Ag NCs was largely attributed to the "joint-toxicity" effect of particulate form of r-Ag NCs and its released Ag + , which resulted in the disruption of the electron transport chain of light reaction and affected the content of key enzymes (RuBP carboxylase/ oxygenase) of Calvin cycle of algae cells. We believe that the present study can also be applied to the assessment of the ecological risk derived from other metal nanoparticles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hug, Laura A.; Thomas, Brian C.; Sharon, Itai

Nitrogen, sulfur and carbon fluxes in the terrestrial subsurface are determined by the intersecting activities of microbial community members, yet the organisms responsible are largely unknown. Metagenomic methods can identify organisms and functions, but genome recovery is often precluded by data complexity. To address this limitation, we developed subsampling assembly methods to re-construct high-quality draft genomes from complex samples. Here, we applied these methods to evaluate the interlinked roles of the most abundant organisms in biogeochemical cycling in the aquifer sediment. Community proteomics confirmed these activities. The eight most abundant organisms belong to novel lineages, and two represent phyla withmore » no previously sequenced genome. Four organisms are predicted to fix carbon via the Calvin Benson Bassham, Wood Ljungdahl or 3-hydroxyproprionate/4-hydroxybutarate pathways. The profiled organisms are involved in the network of denitrification, dissimilatory nitrate reduction to ammonia, ammonia oxidation and sulfate reduction/oxidation, and require substrates supplied by other community members. An ammonium-oxidizing Thaumarchaeote is the most abundant community member, despite low ammonium concentrations in the groundwater. Finally, this organism likely benefits from two other relatively abundant organisms capable of producing ammonium from nitrate, which is abundant in the groundwater. Overall, dominant members of the microbial community are interconnected through exchange of geochemical resources.« less

The Longitudinal Distribution of Condensed Oxygen on Europa

NASA Astrophysics Data System (ADS)

Spencer, J. R.; Grundy, W. M.

2017-12-01

Condensed oxygen is likely to play an important role in the complex chemical environment of the surfaces of the icy Galilean satellites, being important in a radiolytic cycle that includes O3 and H2O2, and which may provide significant chemical energy to the subsurface ocean on Europa. O2 has been identified on Ganymede (Spencer et al. 1995), and subsequently on Europa and Callisto (Spencer and Calvin 2002) by means of its shallow but distinctive 5773 and 6250 Å absorption bands. 5773 Å band strength is up to 2% on Ganymede, but only 0.3% on Europa. O2 on Ganymede exhibits a strong concentration on the trailing hemisphere, suggesting a magnetospheric origin, but the distribution on Europa has been poorly known due to the extreme weakness of the absorption band. We report on new high SNR spectroscopy of the O2 band on Europa, obtained on eight partial nights in June 2017 using the DeVeny Spectrograph on the 4.3-m Lowell Discovery Channel Telescope. The improved SNR of the new data provides the first good constraints on the longitudinal distribution of O2 on Europa, which may provide clues to the origin and evolution of this species.

Molecular adaptations to phosphorus deprivation and comparison with nitrogen deprivation responses in the diatom Phaeodactylum tricornutum.

PubMed

Alipanah, Leila; Winge, Per; Rohloff, Jens; Najafi, Javad; Brembu, Tore; Bones, Atle M

2018-01-01

Phosphorus, an essential element for all living organisms, is a limiting nutrient in many regions of the ocean due to its fast recycling. Changes in phosphate (Pi) availability in aquatic systems affect diatom growth and productivity. We investigated the early adaptive mechanisms in the marine diatom Phaeodactylum tricornutum to P deprivation using a combination of transcriptomics, metabolomics, physiological and biochemical experiments. Our analysis revealed strong induction of gene expression for proteins involved in phosphate acquisition and scavenging, and down-regulation of processes such as photosynthesis, nitrogen assimilation and nucleic acid and ribosome biosynthesis. P deprivation resulted in alterations of carbon allocation through the induction of the pentose phosphate pathway and cytosolic gluconeogenesis, along with repression of the Calvin cycle. Reorganization of cellular lipids was indicated by coordinated induced expression of phospholipases, sulfolipid biosynthesis enzymes and a putative betaine lipid biosynthesis enzyme. A comparative analysis of nitrogen- and phosphorus-deprived P. tricornutum revealed both common and distinct regulation patterns in response to phosphate and nitrate stress. Regulation of central carbon metabolism and amino acid metabolism was similar, whereas unique responses were found in nitrogen assimilation and phosphorus scavenging in nitrogen-deprived and phosphorus-deprived cells, respectively.

Economic Impacts of Prison Growth

DTIC Science & Technology

2010-04-13

allow collective bargaining for public sector correctional workers, proposals to alter rules for the 2010 Census count, and rural development efforts...number of rural areas have chosen to tie their economies to prisons, viewing the institutions as recession-proof development engines. Though many local...correctional authorities. 80 Beale, Calvin L., “ Rural Prisons: An Update”, Rural Development Perspectives, vol. 11, no. 2, March 2001, p. 25. http

A Constraint Embedding Approach for Complex Vehicle Suspension Dynamics

DTIC Science & Technology

2015-04-24

Complex Vehicle Suspension Dynamics ECCOMAS Thematic Conference on Multibody Dynamics 2015 Abhinandan Jain∗, Calvin Kuo#, Paramsothy Jayakumar †, Jonathan...Suspension Dynamics ECCOMAS Thematic Conference on Multibody Dynamics 2015 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...13. SUPPLEMENTARY NOTES ECCOMAS Thematic Conference on Multibody Dynamics 2015, June 29-July 2, 2015, Barcelona, Catalonia, Spain 14. ABSTRACT See

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (86th, Kansas City, Missouri, July 30-August 2, 2003). Miscellaneous Divisions.

ERIC Educational Resources Information Center

2003

The Miscellaneous Divisions of the proceedings contains the following 17 papers: "Analyzing Sequential Art: Visual Narrative Techniques in 'Calvin and Hobbes'" (Sharron M. Hope); "A Critical Vision of Gender in 2002 Campaign Ads" (Janis Teruggi Page); "Personal Impact Assessment of Advertising Culture of 'Whiteness':…

Permanent draft genome of Thermithiobacillus tepidarius DSM 3134 T, a moderately thermophilic, obligately chemolithoautotrophic member of the Acidithiobacillia

DOE PAGES

Boden, Rich; Hutt, Lee P.; Huntemann, Marcel; ...

2016-09-26

Thermithiobacillus tepidarius DSM 3134 T was originally isolated (1983) from the waters of a sulfidic spring entering the Roman Baths (Temple of Sulis-Minerva) at Bath, United Kingdom and is an obligate chemolithoautotroph growing at the expense of reduced sulfur species. This strain has a genome size of 2,958,498 bp. Here we report the genome sequence, annotation and characteristics. The genome comprises 2,902 protein coding and 66 RNA coding genes. Genes responsible for the transaldolase variant of the Calvin-Benson-Bassham cycle were identified along with a biosynthetic horseshoe in lieu of Krebs' cycle sensu stricto. Terminal oxidases were identified, viz. cytochrome cmore » oxidase (cbb 3 , EC 1.9.3.1) and ubiquinol oxidase (bd, EC 1.10.3.10). Metalloresistance genes involved in pathways of arsenic and cadmium resistance were found. Evidence of horizontal gene transfer accounting for 5.9 % of the protein-coding genes was found, including transfer from Thiobacillus spp. and Methylococcus capsulatus Bath, isolated from the same spring. A sox gene cluster was found, similar in structure to those from other Acidithiobacillia - by comparison with Thiobacillus thioparus and Paracoccus denitrificans, an additional gene between soxA and soxB was found, annotated as a DUF302-family protein of unknown function. As the Kelly-Friedrich pathway of thiosulfate oxidation (encoded by sox) is not used in Thermithiobacillus spp., the role of the operon (if any) in this species remains unknown. We speculate that DUF302 and sox genes may have a role in periplasmic trithionate oxidation.« less

Permanent draft genome of Thermithiobacillus tepidarius DSM 3134 T, a moderately thermophilic, obligately chemolithoautotrophic member of the Acidithiobacillia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boden, Rich; Hutt, Lee P.; Huntemann, Marcel

Thermithiobacillus tepidarius DSM 3134 T was originally isolated (1983) from the waters of a sulfidic spring entering the Roman Baths (Temple of Sulis-Minerva) at Bath, United Kingdom and is an obligate chemolithoautotroph growing at the expense of reduced sulfur species. This strain has a genome size of 2,958,498 bp. Here we report the genome sequence, annotation and characteristics. The genome comprises 2,902 protein coding and 66 RNA coding genes. Genes responsible for the transaldolase variant of the Calvin-Benson-Bassham cycle were identified along with a biosynthetic horseshoe in lieu of Krebs' cycle sensu stricto. Terminal oxidases were identified, viz. cytochrome cmore » oxidase (cbb 3 , EC 1.9.3.1) and ubiquinol oxidase (bd, EC 1.10.3.10). Metalloresistance genes involved in pathways of arsenic and cadmium resistance were found. Evidence of horizontal gene transfer accounting for 5.9 % of the protein-coding genes was found, including transfer from Thiobacillus spp. and Methylococcus capsulatus Bath, isolated from the same spring. A sox gene cluster was found, similar in structure to those from other Acidithiobacillia - by comparison with Thiobacillus thioparus and Paracoccus denitrificans, an additional gene between soxA and soxB was found, annotated as a DUF302-family protein of unknown function. As the Kelly-Friedrich pathway of thiosulfate oxidation (encoded by sox) is not used in Thermithiobacillus spp., the role of the operon (if any) in this species remains unknown. We speculate that DUF302 and sox genes may have a role in periplasmic trithionate oxidation.« less

Phosphoketolase pathway contributes to carbon metabolism in cyanobacteria.

PubMed

Xiong, Wei; Lee, Tai-Chi; Rommelfanger, Sarah; Gjersing, Erica; Cano, Melissa; Maness, Pin-Ching; Ghirardi, Maria; Yu, Jianping

2015-12-07

Central carbon metabolism in cyanobacteria comprises the Calvin-Benson-Bassham (CBB) cycle, glycolysis, the pentose phosphate (PP) pathway and the tricarboxylic acid (TCA) cycle. Redundancy in this complex metabolic network renders the rational engineering of cyanobacterial metabolism for the generation of biomass, biofuels and chemicals a challenge. Here we report the presence of a functional phosphoketolase pathway, which splits xylulose-5-phosphate (or fructose-6-phosphate) to acetate precursor acetyl phosphate, in an engineered strain of the model cyanobacterium Synechocystis (ΔglgC/xylAB), in which glycogen synthesis is blocked, and xylose catabolism enabled through the introduction of xylose isomerase and xylulokinase. We show that this mutant strain is able to metabolise xylose to acetate on nitrogen starvation. To see whether acetate production in the mutant is linked to the activity of phosphoketolase, we disrupted a putative phosphoketolase gene (slr0453) in the ΔglgC/xylAB strain, and monitored metabolic flux using (13)C labelling; acetate and 2-oxoglutarate production was reduced in the light. A metabolic flux analysis, based on isotopic data, suggests that the phosphoketolase pathway metabolises over 30% of the carbon consumed by ΔglgC/xylAB during photomixotrophic growth on xylose and CO2. Disruption of the putative phosphoketolase gene in wild-type Synechocystis also led to a deficiency in acetate production in the dark, indicative of a contribution of the phosphoketolase pathway to heterotrophic metabolism. We suggest that the phosphoketolase pathway, previously uncharacterized in photosynthetic organisms, confers flexibility in energy and carbon metabolism in cyanobacteria, and could be exploited to increase the efficiency of cyanobacterial carbon metabolism and photosynthetic productivity.

Chloroplastic thioredoxin-f and thioredoxin-m1/4 play important roles in brassinosteroids-induced changes in CO2 assimilation and cellular redox homeostasis in tomato

PubMed Central

Cheng, Fei; Zhou, Yan-Hong; Xia, Xiao-Jian; Shi, Kai; Zhou, Jie; Yu, Jing-Quan

2014-01-01

Chloroplast thioredoxins (TRXs) and glutathione function as redox messengers in the regulation of photosynthesis. In this work, the roles of chloroplast TRXs in brassinosteroids (BRs)-induced changes in cellular redox homeostasis and CO2 assimilation were studied in the leaves of tomato plants. BRs-deficient d ^im plants showed decreased transcripts of TRX-f, TRX-m2, TRX-m1/4, and TRX-x, while exogenous BRs significantly induced CO2 assimilation and the expression of TRX-f, TRX-m2, TRX-m1/4, and TRX-x. Virus-induced gene silencing (VIGS) of the chloroplast TRX-f, TRX-m2, TRX-m1/4, and TRX-y genes individually increased membrane lipid peroxidation and accumulation of 2-Cys peroxiredoxin dimers, and decreased the activities of the ascorbate–glutathione cycle enzymes and the ratio of reduced glutathione to oxidized glutathione (GSH/GSSG) in the leaves. Furthermore, partial silencing of TRX-f, TRX-m2, TRX-m1/4, and TRX-y resulted in decreased expression of genes involved in the Benson–Calvin cycle and decreased activity of the associated enzymes. Importantly, the BRs-induced increase in CO2 assimilation and the increased expression and activities of antioxidant- and photosynthesis-related genes and enzymes were compromised in the partially TRX-f- and TRX-m1/4-silenced plants. All of these results suggest that TRX-f and TRX-m1/4 are involved in the BRs-induced changes in CO2 assimilation and cellular redox homeostasis in tomato. PMID:24847092

Anaerobic Sulfur Metabolism Coupled to Dissimilatory Iron Reduction in the Extremophile Acidithiobacillus ferrooxidans

PubMed Central

Osorio, Héctor; Mangold, Stefanie; Denis, Yann; Ñancucheo, Ivan; Esparza, Mario; Johnson, D. Barrie; Bonnefoy, Violaine; Dopson, Mark

2013-01-01

Gene transcription (microarrays) and protein levels (proteomics) were compared in cultures of the acidophilic chemolithotroph Acidithiobacillus ferrooxidans grown on elemental sulfur as the electron donor under aerobic and anaerobic conditions, using either molecular oxygen or ferric iron as the electron acceptor, respectively. No evidence supporting the role of either tetrathionate hydrolase or arsenic reductase in mediating the transfer of electrons to ferric iron (as suggested by previous studies) was obtained. In addition, no novel ferric iron reductase was identified. However, data suggested that sulfur was disproportionated under anaerobic conditions, forming hydrogen sulfide via sulfur reductase and sulfate via heterodisulfide reductase and ATP sulfurylase. Supporting physiological evidence for H2S production came from the observation that soluble Cu2+ included in anaerobically incubated cultures was precipitated (seemingly as CuS). Since H2S reduces ferric iron to ferrous in acidic medium, its production under anaerobic conditions indicates that anaerobic iron reduction is mediated, at least in part, by an indirect mechanism. Evidence was obtained for an alternative model implicating the transfer of electrons from S0 to Fe3+ via a respiratory chain that includes a bc1 complex and a cytochrome c. Central carbon pathways were upregulated under aerobic conditions, correlating with higher growth rates, while many Calvin-Benson-Bassham cycle components were upregulated during anaerobic growth, probably as a result of more limited access to carbon dioxide. These results are important for understanding the role of A. ferrooxidans in environmental biogeochemical metal cycling and in industrial bioleaching operations. PMID:23354702

Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

PubMed Central

Tsogtbaatar, Enkhtuul; Cocuron, Jean-Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

2015-01-01

Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography–mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography–tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos. PMID:25711705

Novel magnetite-producing magnetotactic bacteria belonging to the Gammaproteobacteria.

PubMed

Lefèvre, Christopher T; Viloria, Nathan; Schmidt, Marian L; Pósfai, Mihály; Frankel, Richard B; Bazylinski, Dennis A

2012-02-01

Two novel magnetotactic bacteria (MTB) were isolated from sediment and water collected from the Badwater Basin, Death Valley National Park and southeastern shore of the Salton Sea, respectively, and were designated as strains BW-2 and SS-5, respectively. Both organisms are rod-shaped, biomineralize magnetite, and are motile by means of flagella. The strains grow chemolithoautotrophically oxidizing thiosulfate and sulfide microaerobically as electron donors, with thiosulfate oxidized stoichiometrically to sulfate. They appear to utilize the Calvin-Benson-Bassham cycle for autotrophy based on ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) activity and the presence of partial sequences of RubisCO genes. Strains BW-2 and SS-5 biomineralize chains of octahedral magnetite crystals, although the crystals of SS-5 are elongated. Based on 16S rRNA gene sequences, both strains are phylogenetically affiliated with the Gammaproteobacteria class. Strain SS-5 belongs to the order Chromatiales; the cultured bacterium with the highest 16S rRNA gene sequence identity to SS-5 is Thiohalocapsa marina (93.0%). Strain BW-2 clearly belongs to the Thiotrichales; interestingly, the organism with the highest 16S rRNA gene sequence identity to this strain is Thiohalospira alkaliphila (90.2%), which belongs to the Chromatiales. Each strain represents a new genus. This is the first report of magnetite-producing MTB phylogenetically associated with the Gammaproteobacteria. This finding is important in that it significantly expands the phylogenetic diversity of the MTB. Physiology of these strains is similar to other MTB and continues to demonstrate their potential in nitrogen, iron, carbon and sulfur cycling in natural environments.

Metabolome Analysis Reveals Betaine Lipids as Major Source for Triglyceride Formation, and the Accumulation of Sedoheptulose during Nitrogen-Starvation of Phaeodactylum tricornutum.

PubMed

Popko, Jennifer; Herrfurth, Cornelia; Feussner, Kirstin; Ischebeck, Till; Iven, Tim; Haslam, Richard; Hamilton, Mary; Sayanova, Olga; Napier, Jonathan; Khozin-Goldberg, Inna; Feussner, Ivo

2016-01-01

Oleaginous microalgae are considered as a promising resource for the production of biofuels. Especially diatoms arouse interest as biofuel producers since they are most productive in carbon fixation and very flexible to environmental changes in the nature. Naturally, triacylglycerol (TAG) accumulation in algae only occurs under stress conditions like nitrogen-limitation. We focused on Phaeodactylum strain Pt4 (UTEX 646), because of its ability to grow in medium with low salinity and therefore being suited when saline water is less available or for wastewater cultivation strategies. Our data show an increase in neutral lipids during nitrogen-depletion and predominantly 16:0 and 16:1(n-7) accumulated in the TAG fraction. The molecular species composition of TAG suggests a remodeling primarily from the betaine lipid diacylglyceroltrimethylhomoserine (DGTS), but a contribution of the chloroplast galactolipid monogalactosyldiacylglycerol (MGDG) cannot be excluded. Interestingly, the acyl-CoA pool is rich in 20:5(n-3) and 22:6(n-3) in all analyzed conditions, but these fatty acids are almost excluded from TAG. Other metabolites most obviously depleted under nitrogen-starvation were amino acids, lyso-phospholipids and tricarboxylic acid (TCA) cycle intermediates, whereas sulfur-containing metabolites as dimethylsulfoniopropionate, dimethylsulfoniobutyrate and methylsulfate as well as short acyl chain carnitines, propanoyl-carnitine and butanoyl-carnitine increased upon nitrogen-starvation. Moreover, the Calvin cycle may be de-regulated since sedoheptulose accumulated after nitrogen-depletion. Together the data provide now the basis for new strategies to improve lipid production and storage in Phaeodactylum strain Pt4.

Identification and Metabolite Profiling of Chemical Activators of Lipid Accumulation in Green Algae1[OPEN

PubMed Central

2017-01-01

Microalgae are proposed as feedstock organisms useful for producing biofuels and coproducts. However, several limitations must be overcome before algae-based production is economically feasible. Among these is the ability to induce lipid accumulation and storage without affecting biomass yield. To overcome this barrier, a chemical genetics approach was employed in which 43,783 compounds were screened against Chlamydomonas reinhardtii, and 243 compounds were identified that increase triacylglyceride (TAG) accumulation without terminating growth. Identified compounds were classified by structural similarity, and 15 were selected for secondary analyses addressing impacts on growth fitness, photosynthetic pigments, and total cellular protein and starch concentrations. TAG accumulation was verified using gas chromatography-mass spectrometry quantification of total fatty acids, and targeted TAG and galactolipid measurements were performed using liquid chromatography-multiple reaction monitoring/mass spectrometry. These results demonstrated that TAG accumulation does not necessarily proceed at the expense of galactolipid. Untargeted metabolite profiling provided important insights into pathway shifts due to five different compound treatments and verified the anabolic state of the cells with regard to the oxidative pentose phosphate pathway, Calvin cycle, tricarboxylic acid cycle, and amino acid biosynthetic pathways. Metabolite patterns were distinct from nitrogen starvation and other abiotic stresses commonly used to induce oil accumulation in algae. The efficacy of these compounds also was demonstrated in three other algal species. These lipid-inducing compounds offer a valuable set of tools for delving into the biochemical mechanisms of lipid accumulation in algae and a direct means to improve algal oil content independent of the severe growth limitations associated with nutrient deprivation. PMID:28652262

Crooked Timber: The life of Calvin Wells (1908–1978)

PubMed Central

2014-01-01

Calvin Wells was the leading palaeopathologist in the UK between the later 1950s and the early 1970s. He studied medicine at University College London but failed in anatomy and qualified in 1933 with the Conjoint Diploma (MRCS, LRCP). After qualification he began to study obstetrics and after war service in the RAMC he settled in Norfolk (UK), established a small general practice and took up palaeopathology. Although he was usually conservative in diagnosis he tended to over-interpret signs in the skeleton, often publishing descriptions that were more fiction than science. He held firm views on the way in which palaeopathology should be undertaken and in particular he resented the entry into the field of anthropologists without medical training. His major contributions to palaeopathology were related to the study of cremations and the introduction of the notion of pseudopathology, and his writings on these subjects have scarcely been improved upon since. He was extremely well read, warm and encouraging to those with archaeological or medical qualifications, but vituperative about those he disliked. His bone reports, which are a major proportion of his published output, generally were highly regarded but his writing is often marred by sexual innuendo and vulgarity which does his memory little credit. PMID:24585588

Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

PubMed

Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

2014-07-01

Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Single-cell sequencing of Thiomargarita reveals genomic flexibility for adaptation to dynamic redox conditions

DOE PAGES

Winkel, Matthias; Salman-Carvalho, Verena; Woyke, Tanja; ...

2016-06-21

Large, colorless sulfur-oxidizing bacteria (LSB) of the family Beggiatoaceae form thick mats at sulfidic sediment surfaces, where they efficiently detoxify sulfide before it enters the water column. The genus Thiomargarita harbors the largest known free-living bacteria with cell sizes of up to 750 μm in diameter. In addition to their ability to oxidize reduced sulfur compounds, some Thiornargarita spp. are known to store large amounts of nitrate, phosphate and elemental sulfur internally. To date little is known about their energy yielding metabolic pathways, and how these pathways compare to other Beggiatoaceae. Here, we present a draft single-cell genome of amore » chain-forming " Candidatus Thiomargarita nelsonii Thio36", and conduct a comparative analysis to five draft and one full genome of other members of the Beggiatoaceae. " Ca. T. nelsonii Thio36" is able to respire nitrate to both ammonium and dinitrogen, which allows them to flexibly respond to environmental changes. Genes for sulfur oxidation and inorganic carbon fixation confirmed that " Ca. T. nelsonii Thio36" can function as a chemolithoautotroph. Carbon can be fixed via the Calvin-Benson-Bassham cycle, which is common among the Beggiatoaceae. In addition we found key genes of the reductive tricarboxylic acid cycle that point toward an alternative CO 2 fixation pathway. Surprisingly, " Ca. T. nelsonii Thio36" also encodes key genes of the C2-cycle that convert 2-phosphoglycolate to 3-phosphoglycerate during photorespiration in higher plants and cyanobacteria. Moreover, we identified a novel trait of a flavin-based energy bifurcation pathway coupled to a Na +-translocating membrane complex (Rnf). The coupling of these pathways may be key to surviving long periods of anoxia. As other Beggiatoaceae " Ca. T. nelsonii Thio36" encodes many genes similar to those of (filamentous) cyanobacteria. In conclusion, the genome of " Ca. T. nelsonii Thio36" provides additional insight into the ecology of giant sulfur-oxidizing bacteria, and reveals unique genomic features for the Thiomargarita lineage within the Beggiatoaceae.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkel, Matthias; Salman-Carvalho, Verena; Woyke, Tanja

Large, colorless sulfur-oxidizing bacteria (LSB) of the family Beggiatoaceae form thick mats at sulfidic sediment surfaces, where they efficiently detoxify sulfide before it enters the water column. The genus Thiomargarita harbors the largest known free-living bacteria with cell sizes of up to 750 μm in diameter. In addition to their ability to oxidize reduced sulfur compounds, some Thiornargarita spp. are known to store large amounts of nitrate, phosphate and elemental sulfur internally. To date little is known about their energy yielding metabolic pathways, and how these pathways compare to other Beggiatoaceae. Here, we present a draft single-cell genome of amore » chain-forming " Candidatus Thiomargarita nelsonii Thio36", and conduct a comparative analysis to five draft and one full genome of other members of the Beggiatoaceae. " Ca. T. nelsonii Thio36" is able to respire nitrate to both ammonium and dinitrogen, which allows them to flexibly respond to environmental changes. Genes for sulfur oxidation and inorganic carbon fixation confirmed that " Ca. T. nelsonii Thio36" can function as a chemolithoautotroph. Carbon can be fixed via the Calvin-Benson-Bassham cycle, which is common among the Beggiatoaceae. In addition we found key genes of the reductive tricarboxylic acid cycle that point toward an alternative CO 2 fixation pathway. Surprisingly, " Ca. T. nelsonii Thio36" also encodes key genes of the C2-cycle that convert 2-phosphoglycolate to 3-phosphoglycerate during photorespiration in higher plants and cyanobacteria. Moreover, we identified a novel trait of a flavin-based energy bifurcation pathway coupled to a Na +-translocating membrane complex (Rnf). The coupling of these pathways may be key to surviving long periods of anoxia. As other Beggiatoaceae " Ca. T. nelsonii Thio36" encodes many genes similar to those of (filamentous) cyanobacteria. In conclusion, the genome of " Ca. T. nelsonii Thio36" provides additional insight into the ecology of giant sulfur-oxidizing bacteria, and reveals unique genomic features for the Thiomargarita lineage within the Beggiatoaceae.« less

Light versus Dark Carbon Metabolism in Cherry Tomato Fruits

PubMed Central

Laval-Martin, Danielle; Farineau, Jack; Diamond, Jeffrey

1977-01-01

The photosynthetic properties of the internal and peripheral tissues of the cherry tomato fruit (Lycopersicum esculentum var. cerasiforme Dun A. Gray) were investigated. Whole fruit and their isolated tissues evolve large amounts of CO2 in darkness. In the light, this evolution decreases but nevertheless remains a net evolution; 3-(3,4-dichlorophenyl)-1,1-dimethylurea abolishes the effects of light. Incorporation of 14CO2 by leaves and fruit tissues demonstrates that the outer region of the fruit has the highest photosynthetic efficiency on a chlorophyll basis; the internal fruit tissue, richer in chlorophyll, has a much lower efficiency. The identification of intermediates following short term incubations with 14CO2 shows that in darkness the fruit accumulates the majority of label in malate. In the light, leaf tissue exhibits a pattern of incorporation characteristic of C-3 metabolism, whereas fruit tissue exhibits a decreased labeling of malate with a concomitant appearance of label in Calvin cycle intermediates. This is in agreement with the levels and types of carboxylating activities demonstrated in vitro; especially noteworthy is the very low ribulose diphosphate carboxylase activity in the internal fruit tissue. The photosynthetic potential, phosphoenolpyruvate carboxylase activity, and quantities of malate accumulated by fruit tissues are parallel to their chlorophyll content during growth and maturation. PMID:16660204

A novel ethylene responsive factor CitERF13 plays a role in photosynthesis regulation.

PubMed

Xie, Xiu-Lan; Xia, Xiao-Jian; Kuang, Sheng; Zhang, Xi-Li; Yin, Xue-Ren; Yu, Jing-Quan; Chen, Kun-Song

2017-03-01

Ethylene responsive factors (ERFs) act as critical downstream components of the ethylene signalling pathway in regulating plant development and stress responses. However little is known about its role in regulation of photosynthesis. Here, we identified an ethylene-inducible ERF gene in citrus, CitERF13. Transient over-expression of CitERF13 in N. tabacum leaves, resulted in a significant decrease in net photosynthetic rate. Closer examination of photosynthetic activity of PSII and PSI indicated that CitERF13 overexpression led to declines of F v /F m , Y(II) and Y(I). However, change in NPQ was less pronounced. CitERF13 overexpression also significantly reduced V c,max , J max and AQY, indicating inhibition of the Calvin cycle. The expression of photosynthesis-related genes was suppressed to a variable extent in leaf blades transiently over-expressing CitERF13. CitERF13 transient overexpression in tobacco or citrus both resulted in a decline of Chlorophyll content and CitERF13 overexpressing tobacco leaf disc was more susceptible to chlorosis in response to MV-mediated oxidative stress. The results suggest that CitERF13 is potentially involved in suppressing photosynthesis through multiple pathways, for instance, inhibiting photochemical activity of photosynthesis, CO 2 carboxylation capacity and chlorophyll metabolism. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Response of wheat seedlings to ni stress: effects of supplemental calcium.

PubMed

Ouzounidou, G; Moustakas, M; Symeonidis, L; Karataglis, S

2006-04-01

The effect of excess Ni (1 mM Ni) on wheat plants as well as the role of Ca (1 mM Ni+5000 microM Ca) for amelioration of toxicity and recovery of growth and photosynthesis in Ni-stressed wheat was evaluated. Growth, nutrient status (Ca, Mg, Fe, K, Na), and photosynthesis showed a distinct decrease strictly related to the period of treatment. Calcium ameliorated to a certain extent toxic symptoms of Ni, due to antagonistic action between Ni and Ca ions. Since chlorophyll content and variable fluorescence (Fv) decreased significantly, but Fo did not particularly change, the decrease of t1/2 with increasing duration of Ni exposure indicates negative changes on the acceptor side of PSII, which also may result from diminution of Calvin cycle. The maximum quantum yield for energy trapping was also suppressed. Plant transfer to Hoagland solution+5000 microM Ca caused recovery to plant morphology and physiology. Even in control plants, during recovery period an increased Ca concentration in plant tissues with concomitant increased rates of growth and morphology was observed. Ni concentration in plants exposed to 1 mM Ni+5000 microM Ca was lower than in plants exposed to 1 mM Ni. In all treatments a certain increase of plant nutrients was observed during recovery.

Critical biogeochemical functions in the subsurface are associated with bacteria from new phyla and little studied lineages

DOE PAGES

Hug, Laura A.; Thomas, Brian C.; Sharon, Itai; ...

2015-07-22

Nitrogen, sulfur and carbon fluxes in the terrestrial subsurface are determined by the intersecting activities of microbial community members, yet the organisms responsible are largely unknown. Metagenomic methods can identify organisms and functions, but genome recovery is often precluded by data complexity. To address this limitation, we developed subsampling assembly methods to re-construct high-quality draft genomes from complex samples. Here, we applied these methods to evaluate the interlinked roles of the most abundant organisms in biogeochemical cycling in the aquifer sediment. Community proteomics confirmed these activities. The eight most abundant organisms belong to novel lineages, and two represent phyla withmore » no previously sequenced genome. Four organisms are predicted to fix carbon via the Calvin Benson Bassham, Wood Ljungdahl or 3-hydroxyproprionate/4-hydroxybutarate pathways. The profiled organisms are involved in the network of denitrification, dissimilatory nitrate reduction to ammonia, ammonia oxidation and sulfate reduction/oxidation, and require substrates supplied by other community members. An ammonium-oxidizing Thaumarchaeote is the most abundant community member, despite low ammonium concentrations in the groundwater. Finally, this organism likely benefits from two other relatively abundant organisms capable of producing ammonium from nitrate, which is abundant in the groundwater. Overall, dominant members of the microbial community are interconnected through exchange of geochemical resources.« less

Enhanced lipid accumulation and biodiesel production by oleaginous Chlorella protothecoides under a structured heterotrophic-iron (II) induction strategy.

PubMed

Li, Yuqin; Mu, Jinxiu; Chen, Di; Xu, Hua; Han, Fangxin

2015-05-01

A structured heterotrophic-iron (II) induction (HII) strategy was proposed to enhance lipid accumulation in oleaginous Chlorella protothecoides. C. protothecoides subjected to heterotrophic-iron (II) induction achieved a favorable lipid accumulation up to 62 % and a maximum lipid productivity of 820.17 mg/day, representing 2.78-fold and 3.64-fold increase respectively over heterotrophic cultivation alone. HII-induced cells produced significantly elevated levels of 16:0, 18:1(Δ9), and 18:2(Δ9,12) fatty acids (over 90 %). The lipid contents and plant lipid-like fatty acid compositions exhibit the potential of HII-induced C. protothecoides as biodiesel feedstock. Furthermore, 31 altered proteins in HII-induced algal cells were successfully identified. These differentially expressed proteins were assigned into nine molecular function categories, including carbohydrate metabolism, lipid biosynthesis, Calvin cycle, cellular respiration, photosynthesis, energy and transport, protein biosynthesis, regulate and defense, and unclassified. Analysis using the Kyoto encyclopedia of genes and genomes and gene ontology annotation showed that malic enzyme, acyltransferase, and ACP were key metabolic checkpoints found to modulate lipid accumulation in C. protothecoides. The results provided possible applications of HII cultivation strategy in other microalgal species and new possibilities in developing genetic and metabolic engineering microalgae for desirable lipid productivity.

Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge.

PubMed

Cao, Huiluo; Dong, Chunming; Bougouffa, Salim; Li, Jiangtao; Zhang, Weipeng; Shao, Zongze; Bajic, Vladimir B; Qian, Pei-Yuan

2016-03-08

In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex III, which is involved in energy generation. Moreover, we propose that the C-type cytochrome, for example the C553, may play a novel role in electron transfer, adding to our knowledge regarding the energy generation process in the SAR324 cluster. The central carbon metabolism in the described SAR324 genomes exhibits several new features other than methanotrophy e.g. aromatic compound degradation. This suggests that methane oxidation may not be the main central carbon metabolism component in SAR324 cluster bacteria. The reductive acetyl-CoA pathway may potentially be essential in carbon fixation due to the absence of components from the Calvin-Benson cycle. Our study provides insight into the role of recombination events in shaping the genome of the SAR324 group based on a larger number of repeat regions observed, which has been overlooked thus far.

Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge

PubMed Central

Cao, Huiluo; Dong, Chunming; Bougouffa, Salim; Li, Jiangtao; Zhang, Weipeng; Shao, Zongze; Bajic, Vladimir B.; Qian, Pei-Yuan

2016-01-01

In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex III, which is involved in energy generation. Moreover, we propose that the C-type cytochrome, for example the C553, may play a novel role in electron transfer, adding to our knowledge regarding the energy generation process in the SAR324 cluster. The central carbon metabolism in the described SAR324 genomes exhibits several new features other than methanotrophy e.g. aromatic compound degradation. This suggests that methane oxidation may not be the main central carbon metabolism component in SAR324 cluster bacteria. The reductive acetyl-CoA pathway may potentially be essential in carbon fixation due to the absence of components from the Calvin-Benson cycle. Our study provides insight into the role of recombination events in shaping the genome of the SAR324 group based on a larger number of repeat regions observed, which has been overlooked thus far. PMID:26953077

Choline oxidation by intact spinach chloroplasts. [Spinacia oleracea L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weigel, P.; Lerma, C.; Hanson, A.D.

1988-01-01

Plants synthesize betaine by a two-step oxidation of choline (choline ..-->.. betaine aldehyde ..-->.. betaine). Protoplast-derived chloroplasts of spinach (Spinacia oleracea L.) carry out both reactions, more rapidly in light than in darkness. We investigated the light-stimulated oxidation of choline, using spinach chloroplasts isolated directly from leaves. The rates of choline oxidation obtained (dark and light rates: 10-50 and 100-300 nanomoles per hour per milligram chlorophyll, respectively) were approximately 20-fold higher than for protoplast-derived chloroplasts. Betaine aldehyde was the main product. Choline oxidation in darkness and light was suppressed by hypoxia. Neither uncouplers not the Calvin cycle inhibitor glyceraldehyde greatlymore » affected choline oxidation in the light, and maximal choline oxidation was attained far below light saturation of CO/sub 2/ fixation. The light stimulation of choline oxidation was abolished by the PSII inhibitors DCMU and dibromothymoquinone, and was partially restored by adding reduced diaminodurene, an electron donor to PSI. Both methyl viologen and phenazine methosulfate prevented choline oxidation. Adding dihydroxyacetone phosphate, which can generate NADPH in organello, doubled the dark rate of choline oxidation. These results indicate that choline oxidation in chloroplasts requires oxygen, and reducing power generated from PSI. Enzymic reactions consistent with these requirements are discussed.« less

Leaf Proteome Analysis Reveals Prospective Drought and Heat Stress Response Mechanisms in Soybean.

PubMed

Das, Aayudh; Eldakak, Moustafa; Paudel, Bimal; Kim, Dea-Wook; Hemmati, Homa; Basu, Chhandak; Rohila, Jai S

2016-01-01

Drought and heat are among the major abiotic stresses that affect soybean crops worldwide. During the current investigation, the effect of drought, heat, and drought plus heat stresses was compared in the leaves of two soybean varieties, Surge and Davison, combining 2D-DIGE proteomic data with physiology and biochemical analyses. We demonstrated how 25 differentially expressed photosynthesis-related proteins affect RuBisCO regulation, electron transport, Calvin cycle, and carbon fixation during drought and heat stress. We also observed higher abundance of heat stress-induced EF-Tu protein in Surge. It is possible that EF-Tu might have activated heat tolerance mechanisms in the soybean. Higher level expressions of heat shock-related protein seem to be regulating the heat tolerance mechanisms. This study identifies the differential expression of various abiotic stress-responsive proteins that regulate various molecular processes and signaling cascades. One inevitable outcome from the biochemical and proteomics assays of this study is that increase of ROS levels during drought stress does not show significant changes at the phenotypic level in Davison and this seems to be due to a higher amount of carbonic anhydrase accumulation in the cell which aids the cell to become more resistant to cytotoxic concentrations of H2O2.

Leaf Proteome Analysis Reveals Prospective Drought and Heat Stress Response Mechanisms in Soybean

PubMed Central

Das, Aayudh; Eldakak, Moustafa; Paudel, Bimal; Kim, Dea-Wook; Hemmati, Homa; Basu, Chhandak

2016-01-01

Drought and heat are among the major abiotic stresses that affect soybean crops worldwide. During the current investigation, the effect of drought, heat, and drought plus heat stresses was compared in the leaves of two soybean varieties, Surge and Davison, combining 2D-DIGE proteomic data with physiology and biochemical analyses. We demonstrated how 25 differentially expressed photosynthesis-related proteins affect RuBisCO regulation, electron transport, Calvin cycle, and carbon fixation during drought and heat stress. We also observed higher abundance of heat stress-induced EF-Tu protein in Surge. It is possible that EF-Tu might have activated heat tolerance mechanisms in the soybean. Higher level expressions of heat shock-related protein seem to be regulating the heat tolerance mechanisms. This study identifies the differential expression of various abiotic stress-responsive proteins that regulate various molecular processes and signaling cascades. One inevitable outcome from the biochemical and proteomics assays of this study is that increase of ROS levels during drought stress does not show significant changes at the phenotypic level in Davison and this seems to be due to a higher amount of carbonic anhydrase accumulation in the cell which aids the cell to become more resistant to cytotoxic concentrations of H2O2. PMID:27034942

Physiological and Proteomics Analyses Reveal Low-Phosphorus Stress Affected the Regulation of Photosynthesis in Soybean.

PubMed

Chu, Shanshan; Li, Hongyan; Zhang, Xiangqian; Yu, Kaiye; Chao, Maoni; Han, Suoyi; Zhang, Dan

2018-06-06

Previous studies have revealed a significant genetic relationship between phosphorus (P)-efficiency and photosynthesis-related traits in soybean. In this study, we used proteome profiling in combination with expression analysis, biochemical investigations, and leaf ultrastructural analysis to identify the underlying physiological and molecular responses. The expression analysis and ultrastructural analysis showed that the photosynthesis key genes were decreased at transcript levels and the leaf mesophyll and chloroplast were severely damaged after low-P stress. Approximately 55 protein spots showed changes under low-P condition by mass spectrometry, of which 17 were involved in various photosynthetic processes. Further analysis revealed the depression of photosynthesis caused by low-P stress mainly involves the regulation of leaf structure, adenosine triphosphate (ATP) synthesis, absorption and transportation of CO₂, photosynthetic electron transport, production of assimilatory power, and levels of enzymes related to the Calvin cycle. In summary, our findings indicated that the existence of a stringent relationship between P supply and the genomic control of photosynthesis in soybean. As an important strategy to protect soybean photosynthesis, P could maintain the stability of cell structure, up-regulate the enzymes’ activities, recover the process of photosystem II (PSII), and induce the expression of low-P responsive genes and proteins.

Conversion of D-hamamelose into 2-carboxy-D-arabinitol and 2-carboxy-D-arabinitol 1-phosphate in leaves of Phaseolus vulgaris L.

PubMed

Andralojc, P J; Keys, A J; Martindale, W; Dawson, G W; Parry, M A

1996-10-25

[1-14C]Hamamelose (2-hydroxymethyl-D-ribose) was synthesized by reaction of ribulose 5-phosphate with potassium [14C]cyanide, catalytic hydrogenation of the resulting cyanohydrin, and dephosphorylation of the product. Its identity was established by a chromatographic comparison with hamamelose isolated from the bark of witch hazel (Hamamelis virginiana L.). Following vacuum infiltration of the [1-14C]hamamelose into leaf discs from Phaseolus vulgaris L., 14C-labeled 2carboxy-D-arabinitol (CA) and 2-carboxy-D-arabinitol 1-phosphate (CA1P) were formed, in the dark. Conversion of hamamelose to both CA and CA1P in the leaf discs was inhibited by dithiothreitol and sodium fluoride, although at high concentrations of these inhibitors conversion into CA was still evident when conversion into CA1P was totally inhibited. Wheat (Triticum aestivum L.) leaves converted hamamelose into CA without formation of CA1P. Leaves from P. vulgaris contained 68 nmol.g-1 fresh weight of hamamelose in the light and 35 nmol.g-1 fresh weight in the dark. A pathway for the biosynthesis of CA1P from Calvin cycle intermediates is proposed which includes the sequence: hamamelose --> CA --> CA1P.

Multi-Omics of Tomato Glandular Trichomes Reveals Distinct Features of Central Carbon Metabolism Supporting High Productivity of Specialized Metabolites[OPEN

PubMed Central

Bennewitz, Stefan; Bergau, Nick; Athmer, Benedikt; Henning, Anja; Majovsky, Petra; Jiménez-Gómez, José M.

2017-01-01

Glandular trichomes are metabolic cell factories with the capacity to produce large quantities of secondary metabolites. Little is known about the connection between central carbon metabolism and metabolic productivity for secondary metabolites in glandular trichomes. To address this gap in our knowledge, we performed comparative metabolomics, transcriptomics, proteomics, and 13C-labeling of type VI glandular trichomes and leaves from a cultivated (Solanum lycopersicum LA4024) and a wild (Solanum habrochaites LA1777) tomato accession. Specific features of glandular trichomes that drive the formation of secondary metabolites could be identified. Tomato type VI trichomes are photosynthetic but acquire their carbon essentially from leaf sucrose. The energy and reducing power from photosynthesis are used to support the biosynthesis of secondary metabolites, while the comparatively reduced Calvin-Benson-Bassham cycle activity may be involved in recycling metabolic CO2. Glandular trichomes cope with oxidative stress by producing high levels of polyunsaturated fatty acids, oxylipins, and glutathione. Finally, distinct mechanisms are present in glandular trichomes to increase the supply of precursors for the isoprenoid pathways. Particularly, the citrate-malate shuttle supplies cytosolic acetyl-CoA and plastidic glycolysis and malic enzyme support the formation of plastidic pyruvate. A model is proposed on how glandular trichomes achieve high metabolic productivity. PMID:28408661

Simultaneous stimulation of sedoheptulose 1,7-bisphosphatase, fructose 1,6-bisphophate aldolase and the photorespiratory glycine decarboxylase-H protein increases CO2 assimilation, vegetative biomass and seed yield in Arabidopsis.

PubMed

Simkin, Andrew J; Lopez-Calcagno, Patricia E; Davey, Philip A; Headland, Lauren R; Lawson, Tracy; Timm, Stefan; Bauwe, Hermann; Raines, Christine A

2017-07-01

In this article, we have altered the levels of three different enzymes involved in the Calvin-Benson cycle and photorespiratory pathway. We have generated transgenic Arabidopsis plants with altered combinations of sedoheptulose 1,7-bisphosphatase (SBPase), fructose 1,6-bisphophate aldolase (FBPA) and the glycine decarboxylase-H protein (GDC-H) gene identified as targets to improve photosynthesis based on previous studies. Here, we show that increasing the levels of the three corresponding proteins, either independently or in combination, significantly increases the quantum efficiency of PSII. Furthermore, photosynthetic measurements demonstrated an increase in the maximum efficiency of CO 2 fixation in lines over-expressing SBPase and FBPA. Moreover, the co-expression of GDC-H with SBPase and FBPA resulted in a cumulative positive impact on leaf area and biomass. Finally, further analysis of transgenic lines revealed a cumulative increase of seed yield in SFH lines grown in high light. These results demonstrate the potential of multigene stacking for improving the productivity of food and energy crops. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

A carbon sink pathway increases carbon productivity in cyanobacteria.

PubMed

Oliver, John W K; Atsumi, Shota

2015-05-01

The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

A DIGE analysis of developing poplar leaves subjected to ozone reveals major changes in carbon metabolism.

PubMed

Bohler, Sacha; Bagard, Matthieu; Oufir, Mouhssin; Planchon, Sébastien; Hoffmann, Lucien; Jolivet, Yves; Hausman, Jean-François; Dizengremel, Pierre; Renaut, Jenny

2007-05-01

Tropospheric ozone pollution is described as having major negative effects on plants, compromising plant survival. Carbon metabolism is especially affected. In the present work, the effects of chronic ozone exposure were evaluated at the proteomic level in developing leaves of young poplar plants exposed to 120 ppb of ozone for 35 days. Soluble proteins (excluding intrinsic membrane proteins) were extracted from leaves after 3, 14 and 35 days of ozone exposure, as well as 10 days after a recovery period. Proteins (pI 4 to 7) were analyzed by 2-D DIGE experiments, followed by MALDI-TOF-TOF identification. Additional observations were obtained on growth, lesion formation, and leaf pigments analysis. Although treated plants showed large necrotic spots and chlorosis in mature leaves, growth decreased only slightly and plant height was not affected. The number of abscised leaves was higher in treated plants, but new leaf formation was not affected. A decrease in chlorophylls and lutein contents was recorded. A large number of proteins involved in carbon metabolism were identified. In particular, proteins associated with the Calvin cycle and electron transport in the chloroplast were down-regulated. In contrast, proteins associated with glucose catabolism increased in response to ozone exposure. Other identified enzymes are associated with protein folding, nitrogen metabolism and oxidoreductase activity.

Recent Progress in Advanced Nanobiological Materials for Energy and Environmental Applications

PubMed Central

Choi, Hyo-Jick; Montemagno, Carlo D.

2013-01-01

In this review, we briefly introduce our efforts to reconstruct cellular life processes by mimicking natural systems and the applications of these systems to energy and environmental problems. Functional units of in vitro cellular life processes are based on the fabrication of artificial organelles using protein-incorporated polymersomes and the creation of bioreactors. This concept of an artificial organelle originates from the first synthesis of poly(siloxane)-poly(alkyloxazoline) block copolymers three decades ago and the first demonstration of protein activity in the polymer membrane a decade ago. The increased value of biomimetic polymers results from many research efforts to find new applications such as functionally active membranes and a biochemical-producing polymersome. At the same time, foam research has advanced to the point that biomolecules can be efficiently produced in the aqueous channels of foam. Ongoing research includes replication of complex biological processes, such as an artificial Calvin cycle for application in biofuel and specialty chemical production, and carbon dioxide sequestration. We believe that the development of optimally designed biomimetic polymers and stable/biocompatible bioreactors would contribute to the realization of the benefits of biomimetic systems. Thus, this paper seeks to review previous research efforts, examine current knowledge/key technical parameters, and identify technical challenges ahead. PMID:28788424

Exogenous glutathione improves high root-zone temperature tolerance by modulating photosynthesis, antioxidant and osmolytes systems in cucumber seedlings

PubMed Central

Ding, Xiaotao; Jiang, Yuping; He, Lizhong; Zhou, Qiang; Yu, Jizhu; Hui, Dafeng; Huang, Danfeng

2016-01-01

To investigate the physiological responses of plants to high root-zone temperature (HT, 35 °C) stress mitigated by exogenous glutathione (GSH), cucumber (Cucumis sativus L.) seedlings were exposed to HT with or without GSH treatment for 4 days and following with 4 days of recovery. Plant physiological variables, growth, and gene expression related to antioxidant enzymes and Calvin cycle were quantified. The results showed that HT significantly decreased GSH content, the ratio of reduced to oxidized glutathione (GSH/GSSG), chlorophyll content, photosynthesis and related gene expression, shoot height, stem diameter, as well as dry weight. The exogenous GSH treatment clearly lessened the HT stress by increasing the above variables. Meanwhile, HT significantly increased soluble protein content, proline and malondialdehyde (MDA) content as well as O2•− production rate, the gene expression and activities of antioxidant enzymes. The GSH treatment remarkably improved soluble protein content, proline content, antioxidant enzymes activities, and antioxidant enzymes related gene expression, and reduced the MDA content and O2•− production rate compared to no GSH treatment in the HT condition. Our results suggest that exogenous GSH enhances cucumber seedling tolerance of HT stress by modulating the photosynthesis, antioxidant and osmolytes systems to improve physiological adaptation. PMID:27752105

Effects of inorganic phosphate on the light dependent thylakoid energization of intact spinach chloroplasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heineke, D.; Heldt, H.W.; Stitt, M.

1989-09-01

The light dependent energization of the thylakoid membrane was analyzed in isolated intact spinach (Spinacia oleracea L.) chloroplasts incubated with different concentrations of inorganic phosphate (Pi). Two independent methods were used: (a) the accumulation of ({sup 14}C)5,5-dimethyl-2,4-oxazolidinedione and ({sup 14}C)methylamine; (b) the energy dependent chlorophyll fluorescence quenching. The inhibition of CO{sub 2} fixation by superoptimal medium Pi or by adding glyceraldehyde - an inhibitor of the Calvin cycle - leads to an increased energization of the thylakoid membrane; however, the membrane energization decreases when chloroplasts are inhibited by suboptimal Pi. This specific low phosphate effect could be partially reversed bymore » adding oxaloacetate, which regenerates the electron acceptor NADP{sup +} and stimulates linear electron transport. The energization seen in low Pi is, however, always lower than in superoptimal Pi, even in the presence of oxaloacetate. Energization recovers in the presence of low amounts of N,N{prime}-dicyclohexylcarbodiimide, which reacts with proton channels including the coupling factor 1 ATP synthase. N,N{prime}-Dicyclohexylcarbodiimide has no effect on energization of chloroplasts in superoptimal Pi. These results suggest there is a specific low phosphate proton leak in the thylakoids, and its origin is discussed.« less

Food and Agricultural Imports from China

DTIC Science & Technology

2007-07-17

2006. Among the product categories that at least doubled in volume during the period were live animals, wine/ beer , fruit/vegetable juices, wheat...product had complied with safe manufacturing practices (e.g., HACCP for low acid canned foods or seafoods).22 Refusals of Imports from China Of the 720...Phytosanitary Measures,” Choices, 1st quarter 2007. 30 Calvin. 31 Dong. 32 FDA information on HACCP is at [http://www.cfsan.fda.gov/~lrd/haccp.html]. 33

American moralism and the origin of bioethics in the United States.

PubMed

Jonsen, A R

1991-02-01

The theology of John Calvin has deeply affected the American mentality through two streams of thought, Puritanism and Jansenism. These traditions formulate moral problems in terms of absolute, clear principles and avoid casuistic analysis of moral problems. This approach is designated American moralism. This article suggests that the bioethics movement in the United States was stimulated by the moralistic mentality but that the work of the bioethics has departed from this viewpoint.

Progress report on Nuclear Density project with Lawrence Livermore National Lab Year 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, C W; Krastev, P; Ormand, W E

2011-03-11

The main goal for year 2010 was to improve parallelization of the configuration interaction code BIGSTICK, co-written by W. Erich Ormand (LLNL) and Calvin W. Johnson (SDSU), with the parallelization carried out primarily by Plamen Krastev, a postdoc at SDSU and funded in part by this grant. The central computational algorithm is the Lanczos algorithm, which consists of a matrix-vector multiplication (matvec), followed by a Gram-Schmidt reorthogonalization.

American Carrier Air Power at the Dawn of a New Century

DTIC Science & Technology

2005-01-01

Systems, Office of the Secretary of Defense (Operational Test and Evaluation); then–Commander Calvin Craig, OPNAV N81; Captain Kenneth Neubauer and...TACP Tactical Air Control Party TARPS Tactical Air Reconnaissance Pod System TCS Television Camera System TLAM Tomahawk Land-Attack Missile TST Time...store any video imagery acquired by the aircraft’s systems, including the TARPS pod, the pilot’s head-up display (HUD), the Television Camera System (TCS

Water Quality Research Program. Simultaneous, Multiple-Level Withdrawal from a Density Stratified Reservoir

DTIC Science & Technology

1990-11-01

Furusawa , M . 1969. "Experiments on Selective Withdrawal into a Sink from a Uniformly Stratified Fluid--Phenomenon of Layer Separation and Middle-Layer...E. Howington prepared this report. Assisting in the testing were Messrs. Jack E. Davis; Calvin Buie, Jr.; Douglas M . White; and Paul Ahlrich; and Ms...virtually horizontal. Several researchers such as Hino and Furusawa (1969), Croach (1971), Hino (1980), and Farrant (1982) have studied withdrawal

Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

DTIC Science & Technology

2013-08-01

Propulsion Laboratory California Institute of Technology Paramsothy Jayakumar , Ph.D. U.S. Army TARDEC Jim Overholt, Ph.D. U.S. Air Force...NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Paramsothy Jayakumar ; Jim Overholt; Calvin Kuo; Abhi Jain; Havard Grip 5d. PROJECT...Dynamics, Cameron, et al. UNCLASSIFIED Page 10 of 11 REFERENCES [1] P. Jayakumar , W. Smith, B. A. Ross, R. Jategoankar and K. Konarzewski

Water deficit mechanisms in perennial shrubs Cerasus humilis leaves revealed by physiological and proteomic analyses.

PubMed

Yin, Zepeng; Ren, Jing; Zhou, Lijuan; Sun, Lina; Wang, Jiewan; Liu, Yulong; Song, Xingshun

2016-01-01

Drought (Water deficit, WD) poses a serious threat to extensively economic losses of trees throughout the world. Chinese dwarf cherry ( Cerasus humilis ) is a good perennial plant for studying the physiological and sophisticated molecular network under WD. The aim of this study is to identify the effect of WD on C. humilis through physiological and global proteomics analysis and improve understanding of the WD resistance of plants. Currently, physiological parameters were applied to investigate C. humilis response to WD. Moreover, we used two-dimensional gel electrophoresis (2DE) to identify differentially expressed proteins in C. humilis leaves subjected to WD (24 d). Furthermore, we also examined the correlation between protein and transcript levels. Several physiological parameters, including relative water content and Pn were reduced by WD. In addition, the malondialdehyde (MDA), relative electrolyte leakage (REL), total soluble sugar, and proline were increased in WD-treated C. humilis . Comparative proteomic analysis revealed 46 protein spots (representing 43 unique proteins) differentially expressed in C. humilis leaves under WD. These proteins were mainly involved in photosynthesis, ROS scavenging, carbohydrate metabolism, transcription, protein synthesis, protein processing, and nitrogen and amino acid metabolisms, respectively. WD promoted the CO 2 assimilation by increase light reaction and Calvin cycle, leading to the reprogramming of carbon metabolism. Moreover, the accumulation of osmolytes (i.e., proline and total soluble sugar) and enhancement of ascorbate-glutathione cycle and glutathione peroxidase/glutathione s-transferase pathway in leaves could minimize oxidative damage of membrane and other molecules under WD. Importantly, the regulation role of carbohydrate metabolisms (e. g. glycolysis, pentose phosphate pathways, and TCA) was enhanced. These findings provide key candidate proteins for genetic improvement of perennial plants metabolism under WD.

Permanent draft genome of Thiobacillus thioparus DSM 505T, an obligately chemolithoautotrophic member of the Betaproteobacteria

DOE PAGES

Hutt, Lee P.; Huntemann, Marcel; Clum, Alicia; ...

2017-01-19

Thiobacillus thioparus DSM 505 T is one of first two isolated strains of inorganic sulfur-oxidising Bacteria. The original strain of T. thioparus was lost almost 100 years ago and the working type strain is Culture C T (=DSM 505 T = ATCC 8158 T ) isolated by Starkey in 1934 from agricultural soil at Rutgers University, New Jersey, USA. It is an obligate chemolithoautotroph that conserves energy from the oxidation of reduced inorganic sulfur compounds using the Kelly-Trudinger pathway and uses it to fix carbon dioxide It is not capable of heterotrophic or mixotrophic growth. The strain has a genomemore » size of 3,201,518 bp. Here we report the genome sequence, annotation and characteristics. The genome contains 3,135 protein coding and 62 RNA coding genes. Genes encoding the transaldolase variant of the Calvin-Benson-Bassham cycle were also identified and an operon encoding carboxysomes, along with Smith's biosynthetic horseshoe in lieu of Krebs' cycle sensu stricto. Terminal oxidases were identified, viz. cytochrome c oxidase (cbb3, EC 1.9.3.1) and ubiquinol oxidase (bd, EC 1.10.3.10). There is a partial sox operon of the Kelly-Friedrich pathway of inorganic sulfur-oxidation that contains soxXYZAB genes but lacking soxCDEF, there is also a lack of the DUF302 gene previously noted in the sox operon of other members of the 'Proteobacteria' that can use trithionate as an energy source. In spite of apparently not growing anaerobically with denitrification, the nar, nir, nor and nos operons encoding enzymes of denitrification are found in the T. thioparus genome, in the same arrangements as in the true denitrifier T. denitrificans.« less

Life without complex I: proteome analyses of an Arabidopsis mutant lacking the mitochondrial NADH dehydrogenase complex

PubMed Central

Fromm, Steffanie; Senkler, Jennifer; Eubel, Holger; Peterhänsel, Christoph; Braun, Hans-Peter

2016-01-01

The mitochondrial NADH dehydrogenase complex (complex I) is of particular importance for the respiratory chain in mitochondria. It is the major electron entry site for the mitochondrial electron transport chain (mETC) and therefore of great significance for mitochondrial ATP generation. We recently described an Arabidopsis thaliana double-mutant lacking the genes encoding the carbonic anhydrases CA1 and CA2, which both form part of a plant-specific ‘carbonic anhydrase domain’ of mitochondrial complex I. The mutant lacks complex I completely. Here we report extended analyses for systematically characterizing the proteome of the ca1ca2 mutant. Using various proteomic tools, we show that lack of complex I causes reorganization of the cellular respiration system. Reduced electron entry into the respiratory chain at the first segment of the mETC leads to induction of complexes II and IV as well as alternative oxidase. Increased electron entry at later segments of the mETC requires an increase in oxidation of organic substrates. This is reflected by higher abundance of proteins involved in glycolysis, the tricarboxylic acid cycle and branched-chain amino acid catabolism. Proteins involved in the light reaction of photosynthesis, the Calvin cycle, tetrapyrrole biosynthesis, and photorespiration are clearly reduced, contributing to the significant delay in growth and development of the double-mutant. Finally, enzymes involved in defense against reactive oxygen species and stress symptoms are much induced. These together with previously reported insights into the function of plant complex I, which were obtained by analysing other complex I mutants, are integrated in order to comprehensively describe ‘life without complex I’. PMID:27122571

Identification and Metabolite Profiling of Chemical Activators of Lipid Accumulation in Green Algae.

PubMed

Wase, Nishikant; Tu, Boqiang; Allen, James W; Black, Paul N; DiRusso, Concetta C

2017-08-01

Microalgae are proposed as feedstock organisms useful for producing biofuels and coproducts. However, several limitations must be overcome before algae-based production is economically feasible. Among these is the ability to induce lipid accumulation and storage without affecting biomass yield. To overcome this barrier, a chemical genetics approach was employed in which 43,783 compounds were screened against Chlamydomonas reinhardtii , and 243 compounds were identified that increase triacylglyceride (TAG) accumulation without terminating growth. Identified compounds were classified by structural similarity, and 15 were selected for secondary analyses addressing impacts on growth fitness, photosynthetic pigments, and total cellular protein and starch concentrations. TAG accumulation was verified using gas chromatography-mass spectrometry quantification of total fatty acids, and targeted TAG and galactolipid measurements were performed using liquid chromatography-multiple reaction monitoring/mass spectrometry. These results demonstrated that TAG accumulation does not necessarily proceed at the expense of galactolipid. Untargeted metabolite profiling provided important insights into pathway shifts due to five different compound treatments and verified the anabolic state of the cells with regard to the oxidative pentose phosphate pathway, Calvin cycle, tricarboxylic acid cycle, and amino acid biosynthetic pathways. Metabolite patterns were distinct from nitrogen starvation and other abiotic stresses commonly used to induce oil accumulation in algae. The efficacy of these compounds also was demonstrated in three other algal species. These lipid-inducing compounds offer a valuable set of tools for delving into the biochemical mechanisms of lipid accumulation in algae and a direct means to improve algal oil content independent of the severe growth limitations associated with nutrient deprivation. © 2017 American Society of Plant Biologists. All Rights Reserved.

Making a living while starving in the dark: metagenomic insights into the energy dynamics of a carbonate cave.

PubMed

Ortiz, Marianyoly; Legatzki, Antje; Neilson, Julia W; Fryslie, Brandon; Nelson, William M; Wing, Rod A; Soderlund, Carol A; Pryor, Barry M; Maier, Raina M

2014-02-01

Carbonate caves represent subterranean ecosystems that are largely devoid of phototrophic primary production. In semiarid and arid regions, allochthonous organic carbon inputs entering caves with vadose-zone drip water are minimal, creating highly oligotrophic conditions; however, past research indicates that carbonate speleothem surfaces in these caves support diverse, predominantly heterotrophic prokaryotic communities. The current study applied a metagenomic approach to elucidate the community structure and potential energy dynamics of microbial communities, colonizing speleothem surfaces in Kartchner Caverns, a carbonate cave in semiarid, southeastern Arizona, USA. Manual inspection of a speleothem metagenome revealed a community genetically adapted to low-nutrient conditions with indications that a nitrogen-based primary production strategy is probable, including contributions from both Archaea and Bacteria. Genes for all six known CO2-fixation pathways were detected in the metagenome and RuBisCo genes representative of the Calvin-Benson-Bassham cycle were over-represented in Kartchner speleothem metagenomes relative to bulk soil, rhizosphere soil and deep-ocean communities. Intriguingly, quantitative PCR found Archaea to be significantly more abundant in the cave communities than in soils above the cave. MEtaGenome ANalyzer (MEGAN) analysis of speleothem metagenome sequence reads found Thaumarchaeota to be the third most abundant phylum in the community, and identified taxonomic associations to this phylum for indicator genes representative of multiple CO2-fixation pathways. The results revealed that this oligotrophic subterranean environment supports a unique chemoautotrophic microbial community with potentially novel nutrient cycling strategies. These strategies may provide key insights into other ecosystems dominated by oligotrophy, including aphotic subsurface soils or aquifers and photic systems such as arid deserts.

Permanent draft genome of Thiobacillus thioparus DSM 505T, an obligately chemolithoautotrophic member of the Betaproteobacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutt, Lee P.; Huntemann, Marcel; Clum, Alicia

Thiobacillus thioparus DSM 505 T is one of first two isolated strains of inorganic sulfur-oxidising Bacteria. The original strain of T. thioparus was lost almost 100 years ago and the working type strain is Culture C T (=DSM 505 T = ATCC 8158 T ) isolated by Starkey in 1934 from agricultural soil at Rutgers University, New Jersey, USA. It is an obligate chemolithoautotroph that conserves energy from the oxidation of reduced inorganic sulfur compounds using the Kelly-Trudinger pathway and uses it to fix carbon dioxide It is not capable of heterotrophic or mixotrophic growth. The strain has a genomemore » size of 3,201,518 bp. Here we report the genome sequence, annotation and characteristics. The genome contains 3,135 protein coding and 62 RNA coding genes. Genes encoding the transaldolase variant of the Calvin-Benson-Bassham cycle were also identified and an operon encoding carboxysomes, along with Smith's biosynthetic horseshoe in lieu of Krebs' cycle sensu stricto. Terminal oxidases were identified, viz. cytochrome c oxidase (cbb3, EC 1.9.3.1) and ubiquinol oxidase (bd, EC 1.10.3.10). There is a partial sox operon of the Kelly-Friedrich pathway of inorganic sulfur-oxidation that contains soxXYZAB genes but lacking soxCDEF, there is also a lack of the DUF302 gene previously noted in the sox operon of other members of the 'Proteobacteria' that can use trithionate as an energy source. In spite of apparently not growing anaerobically with denitrification, the nar, nir, nor and nos operons encoding enzymes of denitrification are found in the T. thioparus genome, in the same arrangements as in the true denitrifier T. denitrificans.« less

Metabolic Flux Analysis of the Synechocystis sp. PCC 6803 ΔnrtABCD Mutant Reveals a Mechanism for Metabolic Adaptation to Nitrogen-Limited Conditions.

PubMed

Nakajima, Tsubasa; Yoshikawa, Katsunori; Toya, Yoshihiro; Matsuda, Fumio; Shimizu, Hiroshi

2017-03-01

Metabolic flux redirection during nitrogen-limited growth was investigated in the Synechocystis sp. PCC 6803 glucose-tolerant (GT) strain under photoautotrophic conditions by isotopically non-stationary metabolic flux analysis (INST-MFA). A ΔnrtABCD mutant of Synechocystis sp. PCC 6803 was constructed to reproduce phenotypes arising during nitrogen starvation. The ΔnrtABCD mutant and the wild-type GT strain were cultured under photoautotrophic conditions by a photobioreactor. Intracellular metabolites were labeled over a time course using NaH13CO3 as a carbon source. Based on these data, the metabolic flux distributions in the wild-type and ΔnrtABCD cells were estimated by INST-MFA. The wild-type GT and ΔnrtABCD strains displayed similar distribution patterns, although the absolute levels of metabolic flux were lower in ΔnrtABCD. Furthermore, the relative flux levels for glycogen metabolism, anaplerotic reactions and the oxidative pentose phosphate pathway were increased in ΔnrtABCD. This was probably due to the increased expression of enzyme genes that respond to nitrogen depletion. Additionally, we found that the ratio of ATP/NADPH demand increased slightly in the ΔnrtABCD mutant. These results indicated that futile ATP consumption increases under nitrogen-limited conditions because the Calvin-Benson cycle and the oxidative pentose phosphate pathway form a metabolic futile cycle that consumes ATP without CO2 fixation and NADPH regeneration. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A Method of Accounting for Enzyme Costs in Flux Balance Analysis Reveals Alternative Pathways and Metabolite Stores in an Illuminated Arabidopsis Leaf.

PubMed

Cheung, C Y Maurice; Ratcliffe, R George; Sweetlove, Lee J

2015-11-01

Flux balance analysis of plant metabolism is an established method for predicting metabolic flux phenotypes and for exploring the way in which the plant metabolic network delivers specific outcomes in different cell types, tissues, and temporal phases. A recurring theme is the need to explore the flexibility of the network in meeting its objectives and, in particular, to establish the extent to which alternative pathways can contribute to achieving specific outcomes. Unfortunately, predictions from conventional flux balance analysis minimize the simultaneous operation of alternative pathways, but by introducing flux-weighting factors to allow for the variable intrinsic cost of supporting each flux, it is possible to activate different pathways in individual simulations and, thus, to explore alternative pathways by averaging thousands of simulations. This new method has been applied to a diel genome-scale model of Arabidopsis (Arabidopsis thaliana) leaf metabolism to explore the flexibility of the network in meeting the metabolic requirements of the leaf in the light. This identified alternative flux modes in the Calvin-Benson cycle revealed the potential for alternative transitory carbon stores in leaves and led to predictions about the light-dependent contribution of alternative electron flow pathways and futile cycles in energy rebalancing. Notable features of the analysis include the light-dependent tradeoff between the use of carbohydrates and four-carbon organic acids as transitory storage forms and the way in which multiple pathways for the consumption of ATP and NADPH can contribute to the balancing of the requirements of photosynthetic metabolism with the energy available from photon capture. © 2015 American Society of Plant Biologists. All Rights Reserved.

Estimation of microbial metabolism and co-occurrence patterns in fracture groundwaters of deep crystalline bedrock at Olkiluoto, Finland

NASA Astrophysics Data System (ADS)

Bomberg, M.; Lamminmäki, T.; Itävaara, M.

2015-08-01

The microbial diversity in oligotrophic isolated crystalline Fennoscandian Shield bedrock fracture groundwaters is great but the core community has not been identified. Here we characterized the bacterial and archaeal communities in 12 water conductive fractures situated at depths between 296 and 798 m by high throughput amplicon sequencing using the Illumina HiSeq platform. The great sequencing depth revealed that up to 95 and 99 % of the bacterial and archaeal communities, respectively, were composed of only a few common species, i.e. the core microbiome. However, the remaining rare microbiome contained over 3 and 6 fold more bacterial and archaeal taxa. Several clusters of co-occurring rare taxa were identified, which correlated significantly with physicochemical parameters, such as salinity, concentration of inorganic or organic carbon, sulphur, pH and depth. The metabolic properties of the microbial communities were predicted using PICRUSt. The rough prediction showed that the metabolic pathways included commonly fermentation, fatty acid oxidation, glycolysis/gluconeogenesis, oxidative phosphorylation and methanogenesis/anaerobic methane oxidation, but carbon fixation through the Calvin cycle, reductive TCA cycle and the Wood-Ljungdahl pathway was also predicted. The rare microbiome is an unlimited source of genomic functionality in all ecosystems. It may consist of remnants of microbial communities prevailing in earlier conditions on Earth, but could also be induced again if changes in their living conditions occur. In this study only the rare taxa correlated with any physicochemical parameters. Thus these microorganisms can respond to environmental change caused by physical or biological factors that may lead to alterations in the diversity and function of the microbial communities in crystalline bedrock environments.

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components1[W

PubMed Central

Barsan, Cristina; Zouine, Mohamed; Maza, Elie; Bian, Wanping; Egea, Isabel; Rossignol, Michel; Bouyssie, David; Pichereaux, Carole; Purgatto, Eduardo; Bouzayen, Mondher; Latché, Alain; Pech, Jean-Claude

2012-01-01

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome. PMID:22908117

Metabolite fingerprinting of pennycress ( Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

DOE PAGES

Tsogtbaatar, Enkhtuul; Cocuron, Jean -Christophe; Sonera, Marcos Corchado; ...

2015-02-22

Pennycress ( Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis ofmore » oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. In conclusion, this study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.« less

The Effect of Flow Rate and Canister Geometry on the Effectiveness of Removing Carbon Dioxide with Soda Lime.

DTIC Science & Technology

1980-09-01

1969 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN MECHANICAL ENGINEERING from the NAVAL POSTGRADUATE... Science and Engineering 3 ABSTRACT A continuation of experiments initiated by Commander Calvin G. Miller, USN, on the effect of flow rate, flow geometry and...Salvage Department INaval Coastal Systems Center Panama City, Florida 32401 6. Commander, Naval Sea Systems Command 2 Supervisor of Diving (Code GOC

Our Town and Country Society Looks at Itself. Proceedings of the Conference of the American Country Life Association, Inc., National 4-H Club Center (41st, Washington, D.C., July 10-11, 1962).

ERIC Educational Resources Information Center

American Country Life Association, Sioux Falls, SD.

The theme for this conference was "Our Town and Country Society Looks at Itself." The following papers were presented at this conference: (1) "The Miracle of Production--Can We Keep It" (Aubrey D. Gates); (2) "Recent U.S. Population Trends and Their Causes" (Calvin L. Beale and Donald J. Bogue); (3) "Commercial…

A Comparison of Nurses’ Activities Under Two Models of Administration

DTIC Science & Technology

1985-08-01

Angela Sheehan, "Innovation in Cancer Nursing and the Role of the Nurse in Clinical Trials," Progress in Clinical and Biological Research 121 (1983): 87...by Diagnosis-Related Groups,* Annals of Internal Medicine 100 (April 1984): 576. 12Tony DeCrosta, " Megatrends in Nursing: 10 New Directions that are...in Clinical Trials." Progress in Clinical and Biological Research 121 (1983): 87-92. Beyers, Marjorie: Byre, Calvin: Levy, Paul: Mallin, Katherine

Joint Force Quarterly. Number 14, Winter 1996-97

DTIC Science & Technology

1997-03-01

of the Joint Chiefs of Staff by the Institute for National Strategic Studies , National De- fense University, to promote understanding of the integrated...4219 e-mail: JFQ1@ndu.edu Internet: http://www.dtic.mil/doctrine Hans Binnendijk Director Institute for National Strategic Studies Editor-in-Chief... Studies Consulting Editor Calvin B. Kelley Copy Editor ISSN 1070–0692 March 1997 0314Pre 5/6/97 10:52 AM Page 3 competitors or new global powers

3D Modeling of Interior Building Environments and Objects from Noisy Sensor Suites

DTIC Science & Technology

2015-05-14

building environments. The interior environment of a building is scanned by a custom hardware system, which provides raw laser and camera sensor readings...interior environment of a building is scanned by a custom hardware system, which provides raw laser and camera sensor readings used to develop these...seemed straight out of a Calvin & Hobbes strip . As soon as I met the people here, I immediately found that the intellectual adventure matched the

Preparing Capable Decision Makers for an Uncertain Future within Underdeveloped, Degraded and Denied Operational Environments

DTIC Science & Technology

2013-06-01

later in life’ (post primary education ) development effort, but also one which should – nea must – be initiated quite early. This might actually be...and thinker, Thomas Hobbes. (Interestingly, Hobbes apparently was the source for the tiger’s name within the comic strip ‘Calvin and Hobbes’; while...BROAD-BASED EDUCATION – T. HOBBES’ PHILOSOPHIES SCIENCE, that is, Kno wledg e of Con se- qu en ces ; which is called also PHILO- SOPHY Con seq uences

Commuter Air Carrier Symposium (2nd) January 15-16, 1981 .

DTIC Science & Technology

1981-01-16

AJAN B1 UNCLASSIFIED FAA-ASF-300-81-b NL J , E EEEIEEEI mIhIhhEIhEEEI EEIhIhEIhEEIhE IIIIIIIIIIIIIu IIIEII~lElI Second ot Denrpotmn A Fodeol~(ntiorpom...Kathryn B. Creedy AVMARK, Inc. Commuter Air 1120 19th St., N.W. 4827 Rugby Ave. Washington, D.C. 20002 Bethesda, MD 20008 J. Keith Carter Albert J...Commuter Air Piper Aircraft Corp. 4823 Rugby Rd. 3000 Medulla Rd. Bethesda, MD 20014 Lakeland, Florida 33803 -Calvin Davison ’ Crowell & Moring 1100

Program Manager. The Journal of the Defense Systems Management College. Volume 13, Number 4, July-August 1984,

DTIC Science & Technology

1984-08-01

entrepreneurship -’team made up of J. Stanley programs for people (incentives, and innovation; stern disciplinarians; Baumgartner, Calvin Brown, training, hoopla...they let them know that they were Autonomy and Entrepreneurship important to the success of the pro- Simultaneous Loose-Tight ". ,. Every PM we talked to...account hand, managing a fast-food franchise $40,000 which is now his tax base. "-" (IRA) concept. These refreshing de- is a job that can easily be

Founders hope new venture-capital fund will spur medical, biotechnology research

PubMed Central

Gray, Charlotte

1995-01-01

Lack of a coherent industrial strategy and venture capital have hindered scientific researchers in Canada, but the Canadian Medical Discoveries Fund (CMDF) Inc. hopes to change that. Under the leadership of Dr. Henry Friesen, president of the Medical Research Council of Canada, and Dr. Calvin Stiller, head of the multiorgan transplant unit at University Hospital, London, Ont., the new fund proposes to invest in promising medical and biotechnology research companies in Canada. The research council's peerreview system gives the new fund scientific credibility.

From Extraterrestrial to Terrestrial Applications

NASA Astrophysics Data System (ADS)

Strobl, G. F. X.; Laroche, G.; Rasch, K.-D.; Hey, G.

While working to improve transistors in the early 1950s, Bell scientists Gerald Pearson and Calvin Fuller invented the first silicon solar cell. In 1954 Bell Laboratories presented the first solar battery to the public. Despite some early applications on oil platforms, the astronomical price of the cells limited their use to space exploration. In 1958 Vanguard 1, the first satellite with solar cells aboard, went into orbit. As the space program advanced, silicon solar cells became the preferred power source for spacecraft.

Development of Gutless Adenoviral Vectors Encoding Anti Angiogenic Proteins for Therapy of Prostate Cancer

DTIC Science & Technology

2005-01-01

PRINCIPAL INVESTIGATOR: Calvin J. Kuo, M.D., Ph.D. CONTRACTING ORGANIZATION : Stanford University Stanford, California 94305-5401 REPORT DATE: January...cloned in between the I-Scel site and the T’. This extra DNA fragment is used as a stuffer DNA in order to increase the size of the viral genome up to...regularly increasing sizes above the 2 fragments specific for the virus left and right ends can only be explained by the phenomenon known as ’postreplicative

Mitochondrial GPX1 silencing triggers differential photosynthesis impairment in response to salinity in rice plants.

PubMed

Lima-Melo, Yugo; Carvalho, Fabricio E L; Martins, Márcio O; Passaia, Gisele; Sousa, Rachel H V; Neto, Milton C Lima; Margis-Pinheiro, Márcia; Silveira, Joaquim A G

2016-08-01

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform (GPX1) in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines (GPX1s) were tested in absence and presence of 100 mM NaCl for 6 d. Growth reduction of GPX1s line under non-stressful conditions, compared with non-transformed (NT) plants occurred in parallel to increased H2 O2 and decreased GSH contents. These changes occurred concurrently with photosynthesis impairment, particularly in Calvin cycle's reactions, since photochemical efficiency did not change. Thus, GPX1 silencing and downstream molecular/metabolic changes modulated photosynthesis differentially. In contrast, salinity induced reduction in both phases of photosynthesis, which were more impaired in silenced plants. These changes were associated with root morphology alterations but not shoot growth. Both studied lines displayed increased GPX activity but H2 O2 content did not change in response to salinity. Transformed plants exhibited lower photorespiration, water use efficiency and root growth, indicating that GPX1 could be important to salt tolerance. Growth reduction of GPX1s line might be related to photosynthesis impairment, which in turn could have involved a cross talk mechanism between mitochondria and chloroplast originated from redox changes due to GPX1 deficiency. © 2016 Institute of Botany, Chinese Academy of Sciences.

Comparative Proteomic Analyses Provide New Insights into Low Phosphorus Stress Responses in Maize Leaves

PubMed Central

Zhang, Kewei; Liu, Hanhan; Tao, Peilin; Chen, Huan

2014-01-01

Phosphorus deficiency limits plant growth and development. To better understand the mechanisms behind how maize responds to phosphate stress, we compared the proteome analysis results of two groups of maize leaves that were treated separately with 1,000 µM (control, +P) and 5 µM of KH2PO4 (intervention group, −P) for 25 days. In total, 1,342 protein spots were detected on 2-DE maps and 15.43% had changed (P<0.05; ≥1.5-fold) significantly in quantity between the +P and −P groups. These proteins are involved in several major metabolic pathways, including photosynthesis, carbohydrate metabolism, energy metabolism, secondary metabolism, signal transduction, protein synthesis, cell rescue and cell defense and virulence. The results showed that the reduction in photosynthesis under low phosphorus treatment was due to the down-regulation of the proteins involved in CO2 enrichment, the Calvin cycle and the electron transport system. Electron transport and photosynthesis restrictions resulted in a large accumulation of peroxides. Maize has developed many different reactive oxygen species (ROS) scavenging mechanisms to cope with low phosphorus stress, including up-regulating its antioxidant content and antioxidase activity. After being subjected to phosphorus stress over a long period, maize may increase its internal phosphorus utilization efficiency by altering photorespiration, starch synthesis and lipid composition. These results provide important information about how maize responds to low phosphorus stress. PMID:24858307

The methionine salvage pathway in Bacillus subtilis

PubMed Central

Sekowska, Agnieszka; Danchin, Antoine

2002-01-01

Background Polyamine synthesis produces methylthioadenosine, which has to be disposed of. The cell recycles it into methionine through methylthioribose (MTR). Very little was known about MTR recycling for methionine salvage in Bacillus subtilis. Results Using in silico genome analysis and transposon mutagenesis in B. subtilis we have experimentally uncovered the major steps of the dioxygen-dependent methionine salvage pathway, which, although similar to that found in Klebsiella pneumoniae, recruited for its implementation some entirely different proteins. The promoters of the genes have been identified by primer extension, and gene expression was analyzed by Northern blotting and lacZ reporter gene expression. Among the most remarkable discoveries in this pathway is the role of an analog of ribulose diphosphate carboxylase (Rubisco, the plant enzyme used in the Calvin cycle which recovers carbon dioxide from the atmosphere) as a major step in MTR recycling. Conclusions A complete methionine salvage pathway exists in B. subtilis. This pathway is chemically similar to that in K. pneumoniae, but recruited different proteins to this purpose. In particular, a paralogue or Rubisco, MtnW, is used at one of the steps in the pathway. A major observation is that in the absence of MtnW, MTR becomes extremely toxic to the cell, opening an unexpected target for new antimicrobial drugs. In addition to methionine salvage, this pathway protects B. subtilis against dioxygen produced by its natural biotope, the surface of leaves (phylloplane). PMID:12022921

Salt-stress-responsive chloroplast proteins in Brassica juncea genotypes with contrasting salt tolerance and their quantitative PCR analysis.

PubMed

Yousuf, Peerzada Yasir; Ahmad, Altaf; Aref, Ibrahim M; Ozturk, Munir; Hemant; Ganie, Arshid Hussain; Iqbal, Muhammad

2016-11-01

Brassica juncea is mainly cultivated in the arid and semi-arid regions of India where its production is significantly affected by soil salinity. Adequate knowledge of the mechanisms underlying the salt tolerance at sub-cellular levels must aid in developing the salt-tolerant plants. A proper functioning of chloroplasts under salinity conditions is highly desirable to maintain crop productivity. The adaptive molecular mechanisms offered by plants at the chloroplast level to cope with salinity stress must be a prime target in developing the salt-tolerant plants. In the present study, we have analyzed differential expression of chloroplast proteins in two Brassica juncea genotypes, Pusa Agrani (salt-sensitive) and CS-54 (salt-tolerant), under the effect of sodium chloride. The chloroplast proteins were isolated and resolved using 2DE, which facilitated identification and quantification of 12 proteins that differed in expression in the salt-tolerant and salt-sensitive genotypes. The identified proteins were related to a variety of chloroplast-associated molecular processes, including oxygen-evolving process, PS I and PS II functioning, Calvin cycle and redox homeostasis. Expression analysis of genes encoding differentially expressed proteins through real time PCR supported our findings with proteomic analysis. The study indicates that modulating the expression of chloroplast proteins associated with stabilization of photosystems and oxidative defence plays imperative roles in adaptation to salt stress.

A Metabolic Probe-Enabled Strategy Reveals Uptake and Protein Targets of Polyunsaturated Aldehydes in the Diatom Phaeodactylum tricornutum

PubMed Central

Wolfram, Stefanie; Wielsch, Natalie; Hupfer, Yvonne; Mönch, Bettina; Lu-Walther, Hui-Wen; Heintzmann, Rainer; Werz, Oliver; Svatoš, Aleš; Pohnert, Georg

2015-01-01

Diatoms are unicellular algae of crucial importance as they belong to the main primary producers in aquatic ecosystems. Several diatom species produce polyunsaturated aldehydes (PUAs) that have been made responsible for chemically mediated interactions in the plankton. PUA-effects include chemical defense by reducing the reproductive success of grazing copepods, allelochemical activity by interfering with the growth of competing phytoplankton and cell to cell signaling. We applied a PUA-derived molecular probe, based on the biologically highly active 2,4-decadienal, with the aim to reveal protein targets of PUAs and affected metabolic pathways. By using fluorescence microscopy, we observed a substantial uptake of the PUA probe into cells of the diatom Phaeodactylum tricornutum in comparison to the uptake of a structurally closely related control probe based on a saturated aldehyde. The specific uptake motivated a chemoproteomic approach to generate a qualitative inventory of proteins covalently targeted by the α,β,γ,δ-unsaturated aldehyde structure element. Activity-based protein profiling revealed selective covalent modification of target proteins by the PUA probe. Analysis of the labeled proteins gave insights into putative affected molecular functions and biological processes such as photosynthesis including ATP generation and catalytic activity in the Calvin cycle or the pentose phosphate pathway. The mechanism of action of PUAs involves covalent reactions with proteins that may result in protein dysfunction and interference of involved pathways. PMID:26496085

Quantitative Proteomic Analysis of Wheat Cultivars with Differing Drought Stress Tolerance

PubMed Central

Ford, Kristina L.; Cassin, Andrew; Bacic, Antony

2011-01-01

Using a series of multiplexed experiments we studied the quantitative changes in protein abundance of three Australian bread wheat cultivars (Triticum aestivum L.) in response to a drought stress. Three cultivars differing in their ability to maintain grain yield during drought, Kukri (intolerant), Excalibur (tolerant), and RAC875 (tolerant), were grown in the glasshouse with cyclic drought treatment that mimicked conditions in the field. Proteins were isolated from leaves of mature plants and isobaric tags were used to follow changes in the relative protein abundance of 159 proteins. This is the first shotgun proteomics study in wheat, providing important insights into protein responses to drought as well as identifying the largest number of wheat proteins (1,299) in a single study. The changes in the three cultivars at the different time points reflected their differing physiological responses to drought, with the two drought tolerant varieties (Excalibur and RAC875) differing in their protein responses. Excalibur lacked significant changes in proteins during the initial onset of the water deficit in contrast to RAC875 that had a large number of significant changes. All three cultivars had changes consistent with an increase in oxidative stress metabolism and reactive O2 species (ROS) scavenging capacity seen through increases in superoxide dismutases and catalases as well as ROS avoidance through the decreases in proteins involved in photosynthesis and the Calvin cycle. PMID:22639595

Qualitative Distinction of Autotrophic and Heterotrophic Processes at the Leaf Level by Means of Triple Stable Isotope (C–O–H) Patterns

PubMed Central

Kimak, Adam; Kern, Zoltan; Leuenberger, Markus

2015-01-01

Foliar samples were harvested from two oaks, a beech, and a yew at the same site in order to trace the development of the leaves over an entire vegetation season. Cellulose yield and stable isotopic compositions (δ13C, δ18O, and δD) were analyzed on leaf cellulose. All parameters unequivocally define a juvenile and a mature period in the foliar expansion of each species. The accompanying shifts of the δ13C-values are in agreement with the transition from remobilized carbohydrates (juvenile period), to current photosynthates (mature phase). While the opponent seasonal trends of δ18O of blade and vein cellulose are in perfect agreement with the state-of-art mechanistic understanding, the lack of this discrepancy for δD, documented for the first time, is unexpected. For example, the offset range of 18 permil (oak veins) to 57 permil (oak blades) in δD may represent a process driven shift from autotrophic to heterotrophic processes. The shared pattern between blade and vein found for both oak and beech suggests an overwhelming metabolic isotope effect on δD that might be accompanied by proton transfer linked to the Calvin-cycle. These results provide strong evidence that hydrogen and oxygen are under different biochemical controls even at the leaf level. PMID:26635835

Comparative Proteomic Analysis Reveals the Effects of Exogenous Calcium against Acid Rain Stress in Liquidambar formosana Hance Leaves.

PubMed

Hu, Wen-Jun; Wu, Qian; Liu, Xiang; Shen, Zhi-Jun; Chen, Juan; Liu, Ting-Wu; Chen, Juan; Zhu, Chun-Quan; Wu, Fei-Hua; Chen, Lin; Wei, Jia; Qiu, Xiao-Yun; Shen, Guo-Xin; Zheng, Hai-Lei

2016-01-04

Acid rain (AR) impacts forest health by leaching calcium (Ca) away from soils and plants. Ca is an essential element and participates in various plant physiological responses. In the present study, the protective role of exogenous Ca in alleviating AR stress in Liquidambar formosana Hance at the physiological and proteomic levels was examined. Our results showed that low Ca condition resulted in the chlorophyll content and photosynthesis decreasing significantly in L. formosana leaves; however, these effects could be reversed by high Ca supplementation. Further proteomic analyses successfully identified 81 differentially expressed proteins in AR-treated L. formosana under different Ca levels. In particular, some of the proteins are involved in primary metabolism, photosynthesis, energy production, antioxidant defense, transcription, and translation. Moreover, quantitative real time polymerase chain reaction (qRT-PCR) results indicated that low Ca significantly increased the expression level of the investigated Ca-related genes, which can be reversed by high Ca supplementation under AR stress. Further, Western blotting analysis revealed that exogenous Ca supply reduced AR damage by elevating the expression of proteins involved in the Calvin cycle, reactive oxygen species (ROS) scavenging system. These findings allowed us to better understand how woody plants respond to AR stress at various Ca levels and the protective role of exogenous Ca against AR stress in forest tree species.

Rubisco Activases: AAA+ Chaperones Adapted to Enzyme Repair.

PubMed

Bhat, Javaid Y; Thieulin-Pardo, Gabriel; Hartl, F Ulrich; Hayer-Hartl, Manajit

2017-01-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme of the Calvin-Benson-Bassham cycle of photosynthesis, requires conformational repair by Rubisco activase for efficient function. Rubisco mediates the fixation of atmospheric CO 2 by catalyzing the carboxylation of the five-carbon sugar ribulose-1,5-bisphosphate (RuBP). It is a remarkably inefficient enzyme, and efforts to increase crop yields by bioengineering Rubisco remain unsuccessful. This is due in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. To function, Rubisco must undergo an activation process that involves carboxylation of an active site lysine by a non-substrate CO 2 molecule and binding of a Mg 2+ ion. Premature binding of the substrate RuBP results in an inactive enzyme. Moreover, Rubisco can also be inhibited by a range of sugar phosphates, some of which are "misfire" products of its multistep catalytic reaction. The release of the inhibitory sugar molecule is mediated by the AAA+ protein Rubisco activase (Rca), which couples hydrolysis of ATP to the structural remodeling of Rubisco. Rca enzymes are found in the vast majority of photosynthetic organisms, from bacteria to higher plants. They share a canonical AAA+ domain architecture and form six-membered ring complexes but are diverse in sequence and mechanism, suggesting their convergent evolution. In this review, we discuss recent advances in understanding the structure and function of this important group of client-specific AAA+ proteins.

Qualitative Distinction of Autotrophic and Heterotrophic Processes at the Leaf Level by Means of Triple Stable Isotope (C-O-H) Patterns.

PubMed

Kimak, Adam; Kern, Zoltan; Leuenberger, Markus

2015-01-01

Foliar samples were harvested from two oaks, a beech, and a yew at the same site in order to trace the development of the leaves over an entire vegetation season. Cellulose yield and stable isotopic compositions (δ(13)C, δ(18)O, and δD) were analyzed on leaf cellulose. All parameters unequivocally define a juvenile and a mature period in the foliar expansion of each species. The accompanying shifts of the δ(13)C-values are in agreement with the transition from remobilized carbohydrates (juvenile period), to current photosynthates (mature phase). While the opponent seasonal trends of δ(18)O of blade and vein cellulose are in perfect agreement with the state-of-art mechanistic understanding, the lack of this discrepancy for δD, documented for the first time, is unexpected. For example, the offset range of 18 permil (oak veins) to 57 permil (oak blades) in δD may represent a process driven shift from autotrophic to heterotrophic processes. The shared pattern between blade and vein found for both oak and beech suggests an overwhelming metabolic isotope effect on δD that might be accompanied by proton transfer linked to the Calvin-cycle. These results provide strong evidence that hydrogen and oxygen are under different biochemical controls even at the leaf level.

Physiological response of Pinus halepensis needles under ozone and water stress conditions.

PubMed

Manes, Fausto; Donato, Eugenio; Vitale, Marcello

2001-10-01

The aim of this study was to evaluate how physiological processes of potted Pinus halepensis plants, grown under controlled conditions, were affected by ozone (O3) and/or water stress, integrating the gas exchange and biochemical data with fluorescence OJIP polyphasic transient data. Plants submitted to only water stress (T1) and with ozone (T3) showed a strong decrease in stomatal conductance and gas exchange, coinciding with a reduction of maximum yield of photochemistry (varphipo) and very negative values of leaf water potential. Simultaneously, a great increase of both PSII antenna size, indicated by absorption per reaction centre, and electron transport per reaction centre were found. The reduction of photosynthesis in the O3-treated plants (T2) by a slowing down of the Calvin cycle was supported by the increase of related fluorescence parameters such as relative variable fluorescence, heat de-excitation constant, energy de-excitation by spillover, and the decrease of varphipo. We suggest an antagonistic effect between the two stresses to explain the delayed ozone-induced decrease of stomatal conductance values for T3 with respect to T1 plants, by an alteration of the physiological mechanisms of stomatal opening, which involve the increase of intra-cellular free-calcium induced by ABA under co-occurring water shortage. We emphasise the importance of considering the intensity of the individual stress factor in studies concerning the interaction of stresses.

Physiological and proteomic responses to salt stress in chloroplasts of diploid and tetraploid black locust (Robinia pseudoacacia L.)

PubMed Central

Meng, Fanjuan; Luo, Qiuxiang; Wang, Qiuyu; Zhang, Xiuli; Qi, Zhenhua; Xu, Fuling; Lei, Xue; Cao, Yuan; Chow, Wah Soon; Sun, Guangyu

2016-01-01

Salinity is an important abiotic stressor that negatively affects plant growth. In this study, we investigated the physiological and molecular mechanisms underlying moderate and high salt tolerance in diploid (2×) and tetraploid (4×) Robinia pseudoacacia L. Our results showed greater H2O2 accumulation and higher levels of important antioxidative enzymes and non-enzymatic antioxidants in 4× plants compared with 2× plants under salt stress. In addition, 4× leaves maintained a relatively intact structure compared to 2× leaves under a corresponding condition. NaCl treatment didn’t significantly affect the photosynthetic rate, stomatal conductance or leaf intercellular CO2 concentrations in 4× leaves. Moreover, proteins from control and salt treated 2× and 4× leaf chloroplast samples were extracted and separated by two-dimensional gel electrophoresis. A total of 61 spots in 2× (24) and 4× (27) leaves exhibited reproducible and significant changes under salt stress. In addition, 10 proteins overlapped between 2× and 4× plants under salt stress. These identified proteins were grouped into the following 7 functional categories: photosynthetic Calvin-Benson Cycle (26), photosynthetic electron transfer (7), regulation/defense (5), chaperone (3), energy and metabolism (12), redox homeostasis (1) and unknown function (8). This study provides important information of use in the improvement of salt tolerance in plants. PMID:26975701

Systems Analysis of the Response of Photosynthesis, Metabolism, and Growth to an Increase in Irradiance in the Photosynthetic Model Organism Chlamydomonas reinhardtii[C][W][OPEN

PubMed Central

Mettler, Tabea; Mühlhaus, Timo; Hemme, Dorothea; Schöttler, Mark-Aurel; Rupprecht, Jens; Idoine, Adam; Veyel, Daniel; Pal, Sunil Kumar; Yaneva-Roder, Liliya; Winck, Flavia Vischi; Sommer, Frederik; Vosloh, Daniel; Seiwert, Bettina; Erban, Alexander; Burgos, Asdrubal; Arvidsson, Samuel; Schönfelder, Stephanie; Arnold, Anne; Günther, Manuela; Krause, Ursula; Lohse, Marc; Kopka, Joachim; Nikoloski, Zoran; Mueller-Roeber, Bernd; Willmitzer, Lothar; Bock, Ralph; Schroda, Michael; Stitt, Mark

2014-01-01

We investigated the systems response of metabolism and growth after an increase in irradiance in the nonsaturating range in the algal model Chlamydomonas reinhardtii. In a three-step process, photosynthesis and the levels of metabolites increased immediately, growth increased after 10 to 15 min, and transcript and protein abundance responded by 40 and 120 to 240 min, respectively. In the first phase, starch and metabolites provided a transient buffer for carbon until growth increased. This uncouples photosynthesis from growth in a fluctuating light environment. In the first and second phases, rising metabolite levels and increased polysome loading drove an increase in fluxes. Most Calvin-Benson cycle (CBC) enzymes were substrate-limited in vivo, and strikingly, many were present at higher concentrations than their substrates, explaining how rising metabolite levels stimulate CBC flux. Rubisco, fructose-1,6-biosphosphatase, and seduheptulose-1,7-bisphosphatase were close to substrate saturation in vivo, and flux was increased by posttranslational activation. In the third phase, changes in abundance of particular proteins, including increases in plastidial ATP synthase and some CBC enzymes, relieved potential bottlenecks and readjusted protein allocation between different processes. Despite reasonable overall agreement between changes in transcript and protein abundance (R2 = 0.24), many proteins, including those in photosynthesis, changed independently of transcript abundance. PMID:24894045

Proteomic analysis of strawberry leaves infected with Colletotrichum fragariae.

PubMed

Fang, Xianping; Chen, Wenyue; Xin, Ya; Zhang, Hengmu; Yan, Chengqi; Yu, Hong; Liu, Hui; Xiao, Wenfei; Wang, Shuzhen; Zheng, Guizhen; Liu, Hongbo; Jin, Liang; Ma, Huasheng; Ruan, Songlin

2012-07-16

Understanding the defense mechanisms used by anthracnose-resistant strawberries against Colletotrichum infection is important for breeding purposes. To characterize cell responses to Colletotrichum infection, proteomes from strawberry seedling leaves that had or had not been infected with Colletotrichum fragariae were characterized at different time points post infection by 2-DE and by MALDI-TOF/TOF MS/MS and database-searching protein identification. Mass spectrometry identified 49 differentially expressed proteins with significant intensity differences (>1.5-fold, p<0.05) in mock- and C. fragariae-infected leaves at least at one time point. Notably, 2-DE analysis revealed that C. fragariae infection increased the expression of well-known and novel pathogen-responsive proteins whose expression patterns tended to correlate with physiological changes in the leaves. Quantitative real-time PCR was used to examine the transcriptional profiles of infected and uninfected strawberry leaves, and western blotting confirmed the induction of β-1,3-glucanase and a low-molecular-weight heat shock protein in response to C. fragariae infection. During the late phase of infection, proteins involved in the Calvin cycle and glycolysis pathway had suppressed expression. The abundance changes, putative functions, and participation in physiological reactions for the identified proteins produce a pathogen-responsive protein network in C. fragariae-infected strawberry leaves. Together, these findings increase our knowledge of pathogen resistance mechanisms, especially those found in non-model plant species. Copyright © 2012 Elsevier B.V. All rights reserved.

MRAPs, Irregular Warfare, and Pentagon Reform

DTIC Science & Technology

2009-06-01

U P R E S S S TA F F COLONEL DAVID H. GURNEY, USMC (RET.) Director DR. JEFFREY D. SMOTHERMAN Executive Editor GEORGE C. MAERZ Supervisory Editor...LISA M. YAMBRICK Writer-Editor CALVIN B. KELLEY Writer-Editor MARTIN J. PETERS Production Supervisor TARA J. PAREKH Visual Design Editor O T H E R T I T ...L E S I N T H E S E R I E S Choosing War: The Decision to Invade Iraq and Its Aftermath Occasional Paper 5, April 2008 China’s Global Activism

Religious groups as adaptive units.

PubMed

Wilson, D S

2001-01-01

This essay provides a sketch of religion as a set of biologically and culturally evolved adaptations that enable human groups to function as adaptive units. Recent developments in evolutionary biology make such a group-level interpretation of religion more plausible than in the past. A brief survey of relevant concepts is followed by a relatively detailed interpretation of Calvinism as a religious system in which explicit behavioral prescriptions, beliefs about God and his relationship with people, and numerous social control mechanisms combined to change the city of Geneva from a collection of warring factions to a unified population.

Pre-Incident Indicators of Terrorist Incidents: The Identification of Behavioral, Geographic, and Temporal Patterns of Preparatory Conduct

DTIC Science & Technology

2006-03-01

targeting the "pollutants of urban life" by bombing gay bars, porn shops, and abortion clinics in nearby cities. Table 2. Natural breaks statistics for...BACKGROUND Timothy James McVeigh was born on April 23, 1968, near Buffalo, New York, the second child of Bill and Mildred “Mickey” McVeigh. Bill McVeigh...was the couple’s only child together as Calvin and Corinne soon divorced black. hildren in either of his milies. None of his half-brothers or

Sensitivity of California water supply to changes in runoff magnitude and timing: A bottom-up assessment of vulnerabilities and adaptation strategies

NASA Astrophysics Data System (ADS)

Fefer, M.; Dogan, M. S.; Herman, J. D.

2017-12-01

Long-term shifts in the timing and magnitude of reservoir inflows will potentially have significant impacts on water supply reliability in California, though projections remain uncertain. Here we assess the vulnerability of the statewide system to changes in total annual runoff (a function of precipitation) and the fraction of runoff occurring during the winter months (primarily a function of temperature). An ensemble of scenarios is sampled using a bottom-up approach and compared to the most recent available streamflow projections from the state's 4th Climate Assessment. We evaluate these scenarios using a new open-source version of the CALVIN model, a network flow optimization model encompassing roughly 90% of the urban and agricultural water demands in California, which is capable of running scenario ensembles on a high-performance computing cluster. The economic representation of water demand in the model yields several advantages for this type of analysis: optimized reservoir operating policies to minimize shortage cost and the marginal value of adaptation opportunities, defined by shadow prices on infrastructure and regulatory constraints. Results indicate a shift in optimal reservoir operations and high marginal value of additional reservoir storage in the winter months. The collaborative management of reservoirs in CALVIN yields increased storage in downstream reservoirs to store the increased winter runoff. This study contributes an ensemble evaluation of a large-scale network model to investigate uncertain climate projections, and an approach to interpret the results of economic optimization through the lens of long-term adaptation strategies.

KENNEDY SPACE CENTER, FLA. - Daniel L. Tweed, with the Facilities Division, NASA Spaceport Services, addresses attendees at the ribbon cutting for the KSC Security gates. Tweed was project manager. The two new Security gates on Kennedy Parkway (Gate 2) and NASA Parkway (Gate 3) were activated Aug. 1, allowing the general public to have access to the new Space Commerce Way, which will provide access to the Research Park and KSC Visitor Complex, and providing an alternate route for the general public between Titusville and Merritt Island that is accessible 24 hours a day. The gates are staffed 24 hours daily. Others taking part in the ribbon cutting were Center Director Jim Kennedy; Chief, Protective & Safe Guards Office, Calvin L. Burch; SGS Deputy Program Manager William A. Sample; and Bobby Porter, with Oneida Construction.

NASA Image and Video Library

2003-08-27

KENNEDY SPACE CENTER, FLA. - Daniel L. Tweed, with the Facilities Division, NASA Spaceport Services, addresses attendees at the ribbon cutting for the KSC Security gates. Tweed was project manager. The two new Security gates on Kennedy Parkway (Gate 2) and NASA Parkway (Gate 3) were activated Aug. 1, allowing the general public to have access to the new Space Commerce Way, which will provide access to the Research Park and KSC Visitor Complex, and providing an alternate route for the general public between Titusville and Merritt Island that is accessible 24 hours a day. The gates are staffed 24 hours daily. Others taking part in the ribbon cutting were Center Director Jim Kennedy; Chief, Protective & Safe Guards Office, Calvin L. Burch; SGS Deputy Program Manager William A. Sample; and Bobby Porter, with Oneida Construction.

Spatial Differences in East Scotia Ridge Hydrothermal Vent Food Webs: Influences of Chemistry, Microbiology and Predation on Trophodynamics

PubMed Central

Reid, William D. K.; Sweeting, Christopher J.; Wigham, Ben D.; Zwirglmaier, Katrin; Hawkes, Jeffrey A.; McGill, Rona A. R.; Linse, Katrin; Polunin, Nicholas V. C.

2013-01-01

The hydrothermal vents on the East Scotia Ridge are the first to be explored in the Antarctic and are dominated by large peltospiroid gastropods, stalked barnacles (Vulcanolepas sp.) and anomuran crabs (Kiwa sp.) but their food webs are unknown. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. δ13C of dissolved inorganic carbon from vent fluids ranged from −4.6‰ to 0.8‰ at E2 and from −4.4‰ to 1.5‰ at E9. The lowest macroconsumer δ13C was observed in peltospiroid gastropods (−30.0‰ to −31.1‰) and indicated carbon fixation via the Calvin-Benson-Bassham (CBB) cycle by endosymbiotic gamma-Proteobacteria. Highest δ13C occurred in Kiwa sp. (−19.0‰ to −10.5‰), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. δ13C differed among sites, which were attributed to spatial differences in the epibiont community and the relative contribution of carbon fixed via the reductive tricarboxylic acid (rTCA) and CBB cycles assimilated by Kiwa sp. Site differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the δ13C and δ34S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the hydrothermal vent food webs vary between the sites. PMID:23762393

Investigating the hydrological origins of Blood Falls - geomicrobiological insights into a briny subglacial Antarctic aquifer

NASA Astrophysics Data System (ADS)

Mikucki, J.; Tulaczyk, S. M.; Purcell, A. M.; Dachwald, B.; Lyons, W. B.; Welch, K. A.; Auken, E.; Dugan, H. A.; Walter, J. I.; Pettit, E. C.; Doran, P. T.; Virginia, R. A.; Schamper, C.; Foley, N.; Feldmann, M.; Espe, C.; Ghosh, D.; Francke, G.

2015-12-01

Subglacial waters tend to accumulate solutes from extensive rock-water interactions, which, when released to the surface, can provide nutrients to surface ecosystems providing a 'hot spot' for microbial communities. Blood Falls, an iron-rich, saline feature at the terminus of Taylor Glacier in the McMurdo Dry Valleys, Antarctica is a well-studied subglacial discharge. Here we present an overview of geophysical surveys, thermomechanical drilling exploration and geomicrobiological analyses of the Blood Falls system. A helicopter-borne transient electromagnetic system (SkyTEM) flown over the Taylor Glacier revealed a surprisingly extensive subglacial aquifer and indicates that Blood Falls may be the only surface manifestation of this extensive briny groundwater. Ground-based temperature sensing and GPR data combined with the helicopter-borne TEM data enabled targeted drilling into the englacial conduit that delivers brine to the surface. During the 2014-15 austral summer field season, we used a novel ice-melting drill (the IceMole) to collect englacial brine for geomicrobiological analyses. Results from previously collected outflow and more recent samples indicate that the brine harbors a metabolically active microbial community that persists, despite cold, dark isolation. Isotope geochemistry and molecular analysis of functional genes from BF suggested that a catalytic or 'cryptic' sulfur cycle was linked to iron reduction. Recent metagenomic analysis confirms the presence of numerous genes involved in oxidative and reductive sulfur transformations. Metagenomic and metabolic activity data also indicate that subglacial dark CO2 fixation occurs via various pathways. Genes encoding key steps in CO2 fixation pathways including the Calvin Benson Basham and Wood Ljungdahl pathway were present and brine samples showed measureable uptake of 14C-labeled bicarbonate. These results support the notion that, like the deep subsurface, subglacial environments are chemosynthetic, deriving energy in part by cycling iron and sulfur compounds. Collectively our interdisciplinary dataset indicates that subsurface brines are widespread in the Taylor Valley polar desert and this previously unknown groundwater network likely supports unique microbial life.

Steady states and stability in metabolic networks without regulation.

PubMed

Ivanov, Oleksandr; van der Schaft, Arjan; Weissing, Franz J

2016-07-21

Metabolic networks are often extremely complex. Despite intensive efforts many details of these networks, e.g., exact kinetic rates and parameters of metabolic reactions, are not known, making it difficult to derive their properties. Considerable effort has been made to develop theory about properties of steady states in metabolic networks that are valid for any values of parameters. General results on uniqueness of steady states and their stability have been derived with specific assumptions on reaction kinetics, stoichiometry and network topology. For example, deep results have been obtained under the assumptions of mass-action reaction kinetics, continuous flow stirred tank reactors (CFSTR), concordant reaction networks and others. Nevertheless, a general theory about properties of steady states in metabolic networks is still missing. Here we make a step further in the quest for such a theory. Specifically, we study properties of steady states in metabolic networks with monotonic kinetics in relation to their stoichiometry (simple and general) and the number of metabolites participating in every reaction (single or many). Our approach is based on the investigation of properties of the Jacobian matrix. We show that stoichiometry, network topology, and the number of metabolites that participate in every reaction have a large influence on the number of steady states and their stability in metabolic networks. Specifically, metabolic networks with single-substrate-single-product reactions have disconnected steady states, whereas in metabolic networks with multiple-substrates-multiple-product reactions manifolds of steady states arise. Metabolic networks with simple stoichiometry have either a unique globally asymptotically stable steady state or asymptotically stable manifolds of steady states. In metabolic networks with general stoichiometry the steady states are not always stable and we provide conditions for their stability. In order to demonstrate the biological relevance we illustrate the results on the examples of the TCA cycle, the mevalonate pathway and the Calvin cycle. Copyright © 2016 Elsevier Ltd. All rights reserved.

GAPDH-A Recruits a Plant Virus Movement Protein to Cortical Virus Replication Complexes to Facilitate Viral Cell-to-Cell Movement

PubMed Central

Kaido, Masanori; Abe, Kazutomo; Mine, Akira; Hyodo, Kiwamu; Taniguchi, Takako; Taniguchi, Hisaaki; Mise, Kazuyuki; Okuno, Tetsuro

2014-01-01

The formation of virus movement protein (MP)-containing punctate structures on the cortical endoplasmic reticulum is required for efficient intercellular movement of Red clover necrotic mosaic virus (RCNMV), a bipartite positive-strand RNA plant virus. We found that these cortical punctate structures constitute a viral replication complex (VRC) in addition to the previously reported aggregate structures that formed adjacent to the nucleus. We identified host proteins that interacted with RCNMV MP in virus-infected Nicotiana benthamiana leaves using a tandem affinity purification method followed by mass spectrometry. One of these host proteins was glyceraldehyde 3-phosphate dehydrogenase-A (NbGAPDH-A), which is a component of the Calvin-Benson cycle in chloroplasts. Virus-induced gene silencing of NbGAPDH-A reduced RCNMV multiplication in the inoculated leaves, but not in the single cells, thereby suggesting that GAPDH-A plays a positive role in cell-to-cell movement of RCNMV. The fusion protein of NbGAPDH-A and green fluorescent protein localized exclusively to the chloroplasts. In the presence of RCNMV RNA1, however, the protein localized to the cortical VRC as well as the chloroplasts. Bimolecular fluorescence complementation assay and GST pulldown assay confirmed in vivo and in vitro interactions, respectively, between the MP and NbGAPDH-A. Furthermore, gene silencing of NbGAPDH-A inhibited MP localization to the cortical VRC. We discuss the possible roles of NbGAPDH-A in the RCNMV movement process. PMID:25411849

Dynamic photosynthesis in different environmental conditions.

PubMed

Kaiser, Elias; Morales, Alejandro; Harbinson, Jeremy; Kromdijk, Johannes; Heuvelink, Ep; Marcelis, Leo F M

2015-05-01

Incident irradiance on plant leaves often fluctuates, causing dynamic photosynthesis. Whereas steady-state photosynthetic responses to environmental factors have been extensively studied, knowledge of dynamic modulation of photosynthesis remains scarce and scattered. This review addresses this discrepancy by summarizing available data and identifying the research questions necessary to advance our understanding of interactions between environmental factors and dynamic behaviour of photosynthesis using a mechanistic framework. Firstly, dynamic photosynthesis is separated into sub-processes related to proton and electron transport, non-photochemical quenching, control of metabolite flux through the Calvin cycle (activation states of Rubisco and RuBP regeneration, and post-illumination metabolite turnover), and control of CO₂ supply to Rubisco (stomatal and mesophyll conductance changes). Secondly, the modulation of dynamic photosynthesis and its sub-processes by environmental factors is described. Increases in ambient CO₂ concentration and temperature (up to ~35°C) enhance rates of photosynthetic induction and decrease its loss, facilitating more efficient dynamic photosynthesis. Depending on the sensitivity of stomatal conductance, dynamic photosynthesis may additionally be modulated by air humidity. Major knowledge gaps exist regarding environmental modulation of loss of photosynthetic induction, dynamic changes in mesophyll conductance, and the extent of limitations imposed by stomatal conductance for different species and environmental conditions. The study of mutants or genetic transformants for specific processes under various environmental conditions could provide significant progress in understanding the control of dynamic photosynthesis. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

RubisCO Gene Clusters Found in a Metagenome Microarray from Acid Mine Drainage

PubMed Central

Guo, Xue; Yin, Huaqun; Cong, Jing; Dai, Zhimin; Liang, Yili

2013-01-01

The enzyme responsible for carbon dioxide fixation in the Calvin cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), is always detected as a phylogenetic marker to analyze the distribution and activity of autotrophic bacteria. However, such an approach provides no indication as to the significance of genomic content and organization. Horizontal transfers of RubisCO genes occurring in eubacteria and plastids may seriously affect the credibility of this approach. Here, we presented a new method to analyze the diversity and genomic content of RubisCO genes in acid mine drainage (AMD). A metagenome microarray containing 7,776 large-insertion fosmids was constructed to quickly screen genome fragments containing RubisCO form I large-subunit genes (cbbL). Forty-six cbbL-containing fosmids were detected, and six fosmids were fully sequenced. To evaluate the reliability of the metagenome microarray and understand the microbial community in AMD, the diversities of cbbL and the 16S rRNA gene were analyzed. Fosmid sequences revealed that the form I RubisCO gene cluster could be subdivided into form IA and IB RubisCO gene clusters in AMD, because of significant divergences in molecular phylogenetics and conservative genomic organization. Interestingly, the form I RubisCO gene cluster coexisted with the form II RubisCO gene cluster in one fosmid genomic fragment. Phylogenetic analyses revealed that horizontal transfers of RubisCO genes may occur widely in AMD, which makes the evolutionary history of RubisCO difficult to reconcile with organismal phylogeny. PMID:23335778

Quantitative analyses of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large-subunit genes (cbbL) in typical paddy soils.

PubMed

Xiao, Ke-Qing; Bao, Peng; Bao, Qiong-Li; Jia, Yan; Huang, Fu-Yi; Su, Jian-Qiang; Zhu, Yong-Guan

2014-01-01

The Calvin cycle is known to be the major pathway for CO2 fixation, but our current understanding of its occurrence and importance in paddy soils is poor. In this study, the diversity of three ribulose-1,5-bisphosphate carboxylase/oxygenase large-subunit genes (cbbLG, cbbLR, cbbM) was investigated by clone library, T-RFLP, qPCR, and enzyme assay in five paddy soils in China. The cbbLG sequences revealed a relatively low level of diversity and were mostly related to the sequences of species from Thiobacillus. In contrast, highly diverse cbbLR and cbbM sequences were dispersed on the phylogenetic trees, and most of them were distantly related to known sequences, even forming separate clusters. Abundances of three cbbL genes ranged from 10(6) to 10(9) copies g(-1) soil, and cbbLR outnumbered cbbM and cbbLG in all soil samples, indicating that cbbLR may play a more important role than other two cbbL genes. Soil properties significantly influenced cbbL diversity in five paddy soils, of which clay content, C/N ratio, CEC, pH, and SOC correlated well with variations in microbial composition and abundance. In summary, this study provided a comparison of three cbbL genes, advancing our understanding of their role in carbon sequestration and nutrient turnover in the paddy soil. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Warming delays autumn declines in photosynthetic capacity in a boreal conifer, Norway spruce (Picea abies).

PubMed

Stinziano, Joseph R; Hüner, Norman P A; Way, Danielle A

2015-12-01

Climate change, via warmer springs and autumns, may lengthen the carbon uptake period of boreal tree species, increasing the potential for carbon sequestration in boreal forests, which could help slow climate change. However, if other seasonal cues such as photoperiod dictate when photosynthetic capacity declines, warmer autumn temperatures may have little effect on when carbon uptake capacity decreases in these species. We investigated whether autumn warming would delay photosynthetic decline in Norway spruce (Picea abies (L.) H. Karst.) by growing seedlings under declining weekly photoperiods and weekly temperatures either at ambient temperature or a warming treatment 4 °C above ambient. Photosynthetic capacity was relatively constant in both treatments when weekly temperatures were >8 °C, but declined rapidly at lower temperatures, leading to a delay in the autumn decline in photosynthetic capacity in the warming treatment. The decline in photosynthetic capacity was not related to changes in leaf nitrogen or chlorophyll concentrations, but was correlated with a decrease in the apparent fraction of leaf nitrogen invested in Rubisco, implicating a shift in nitrogen allocation away from the Calvin cycle at low autumn growing temperatures. Our data suggest that as the climate warms, the period of net carbon uptake will be extended in the autumn for boreal forests dominated by Norway spruce, which could increase total carbon uptake in these forests. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Photoautotrophic Polyhydroxybutyrate Granule Formation Is Regulated by Cyanobacterial Phasin PhaP in Synechocystis sp. Strain PCC 6803

PubMed Central

Hauf, Waldemar; Watzer, Björn; Roos, Nora; Klotz, Alexander

2015-01-01

Cyanobacteria are photoautotrophic microorganisms which fix atmospheric carbon dioxide via the Calvin-Benson cycle to produce carbon backbones for primary metabolism. Fixed carbon can also be stored as intracellular glycogen, and in some cyanobacterial species like Synechocystis sp. strain PCC 6803, polyhydroxybutyrate (PHB) accumulates when major nutrients like phosphorus or nitrogen are absent. So far only three enzymes which participate in PHB metabolism have been identified in this organism, namely, PhaA, PhaB, and the heterodimeric PHB synthase PhaEC. In this work, we describe the cyanobacterial PHA surface-coating protein (phasin), which we term PhaP, encoded by ssl2501. Translational fusion of Ssl2501 with enhanced green fluorescent protein (eGFP) showed a clear colocalization to PHB granules. A deletion of ssl2501 reduced the number of PHB granules per cell, whereas the mean PHB granule size increased as expected for a typical phasin. Although deletion of ssl2501 had almost no effect on the amount of PHB, the biosynthetic activity of PHB synthase was negatively affected. Secondary-structure prediction and circular dichroism (CD) spectroscopy of PhaP revealed that the protein consists of two α-helices, both of them associating with PHB granules. Purified PhaP forms oligomeric structures in solution, and both α-helices of PhaP contribute to oligomerization. Together, these results support the idea that Ssl2501 encodes a cyanobacterial phasin, PhaP, which regulates the surface-to-volume ratio of PHB granules. PMID:25911471

Rubisco Activases: AAA+ Chaperones Adapted to Enzyme Repair

PubMed Central

Bhat, Javaid Y.; Thieulin-Pardo, Gabriel; Hartl, F. Ulrich; Hayer-Hartl, Manajit

2017-01-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme of the Calvin-Benson-Bassham cycle of photosynthesis, requires conformational repair by Rubisco activase for efficient function. Rubisco mediates the fixation of atmospheric CO2 by catalyzing the carboxylation of the five-carbon sugar ribulose-1,5-bisphosphate (RuBP). It is a remarkably inefficient enzyme, and efforts to increase crop yields by bioengineering Rubisco remain unsuccessful. This is due in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. To function, Rubisco must undergo an activation process that involves carboxylation of an active site lysine by a non-substrate CO2 molecule and binding of a Mg2+ ion. Premature binding of the substrate RuBP results in an inactive enzyme. Moreover, Rubisco can also be inhibited by a range of sugar phosphates, some of which are “misfire” products of its multistep catalytic reaction. The release of the inhibitory sugar molecule is mediated by the AAA+ protein Rubisco activase (Rca), which couples hydrolysis of ATP to the structural remodeling of Rubisco. Rca enzymes are found in the vast majority of photosynthetic organisms, from bacteria to higher plants. They share a canonical AAA+ domain architecture and form six-membered ring complexes but are diverse in sequence and mechanism, suggesting their convergent evolution. In this review, we discuss recent advances in understanding the structure and function of this important group of client-specific AAA+ proteins. PMID:28443288

Influence of the variation potential on photosynthetic flows of light energy and electrons in pea.

PubMed

Sukhova, Ekaterina; Mudrilov, Maxim; Vodeneev, Vladimir; Sukhov, Vladimir

2018-05-01

Local damage (mainly burning, heating, and mechanical wounding) induces propagation of electrical signals, namely, variation potentials, which are important signals during the life of plants that regulate different physiological processes, including photosynthesis. It is known that the variation potential decreases the rate of CO 2 assimilation by the Calvin-Benson cycle; however, its influence on light reactions has been poorly investigated. The aim of our work was to investigate the influence of the variation potential on the light energy flow that is absorbed, trapped and dissipated per active reaction centre in photosystem II and on the flow of electrons through the chloroplast electron transport chain. We analysed chlorophyll fluorescence in pea leaves using JIP-test and PAM-fluorometry; we also investigated delayed fluorescence. The electrical signals were registered using extracellular electrodes. We showed that the burning-induced variation potential stimulated a nonphotochemical loss of energy in photosystem II under dark conditions. It was also shown that the variation potential gradually increased the flow of light energy absorbed, trapped and dissipated by photosystem II. These changes were likely caused by an increase in the fraction of absorbed light distributed to photosystem II. In addition, the variation potential induced a transient increase in electron flow through the photosynthetic electron transport chain. Some probable mechanisms for the influence of the variation potential on the light reactions of photosynthesis (including the potential role of intracellular pH decrease) are discussed in the work.

Enhanced photosynthesis and redox energy production contribute to salinity tolerance in Dunaliella as revealed by homology-based proteomics.

PubMed

Liska, Adam J; Shevchenko, Andrej; Pick, Uri; Katz, Adriana

2004-09-01

Salinity is a major limiting factor for the proliferation of plants and inhibits central metabolic activities such as photosynthesis. The halotolerant green alga Dunaliella can adapt to hypersaline environments and is considered a model photosynthetic organism for salinity tolerance. To clarify the molecular basis for salinity tolerance, a proteomic approach has been applied for identification of salt-induced proteins in Dunaliella. Seventy-six salt-induced proteins were selected from two-dimensional gel separations of different subcellular fractions and analyzed by mass spectrometry (MS). Application of nanoelectrospray mass spectrometry, combined with sequence-similarity database-searching algorithms, MS BLAST and MultiTag, enabled identification of 80% of the salt-induced proteins. Salinity stress up-regulated key enzymes in the Calvin cycle, starch mobilization, and redox energy production; regulatory factors in protein biosynthesis and degradation; and a homolog of a bacterial Na(+)-redox transporters. The results indicate that Dunaliella responds to high salinity by enhancement of photosynthetic CO(2) assimilation and by diversion of carbon and energy resources for synthesis of glycerol, the osmotic element in Dunaliella. The ability of Dunaliella to enhance photosynthetic activity at high salinity is remarkable because, in most plants and cyanobacteria, salt stress inhibits photosynthesis. The results demonstrated the power of MS BLAST searches for the identification of proteins in organisms whose genomes are not known and paved the way for dissecting molecular mechanisms of salinity tolerance in algae and higher plants.

Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest)--ghost and blue mud shrimp

USGS Publications Warehouse

Hornig, S.; Sterling, A.; Smith, Styles

1989-01-01

Geographic range: The ghost shrimp is found in intertidal areas along the west coast of North America from Mutiny Bay, Alaska, to the mouth of the Tijuana River, San Diego County, California; MacGinitie (1934) and Ricketts and Calvin (1968) reported finding specimens as far south as El Estuario de Punto Banda, Baja California Norte, Mexico. The blue mud shrimp is found from southeastern Alaska to San Quentin Bay (Bahia de San Quentin) in Baja California Norte. The general distribution of the two species in the Pacific Northwest is identical (Figure 3).

Temperature-package power correlations for open-mode geologic disposal concepts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardin, Ernest.

2013-02-01

Logistical simulation of spent nuclear fuel (SNF) management in the U.S. combines storage, transportation and disposal elements to evaluate schedule, cost and other resources needed for all major operations leading to final geologic disposal. Geologic repository reference options are associated with limits on waste package thermal power output at emplacement, in order to meet limits on peak temperature for certain key engineered and natural barriers. These package power limits are used in logistical simulation software such as CALVIN, as threshold requirements that must be met by means of decay storage or SNF blending in waste packages, before emplacement in amore » repository. Geologic repository reference options include enclosed modes developed for crystalline rock, clay or shale, and salt. In addition, a further need has been addressed for open modes in which SNF can be emplaced in a repository, then ventilated for decades or longer to remove heat, prior to permanent repository closure. For each open mode disposal concept there are specified durations for surface decay storage (prior to emplacement), repository ventilation, and repository closure operations. This study simulates those steps for several timing cases, and for SNF with three fuel-burnup characteristics, to develop package power limits at which waste packages can be emplaced without exceeding specified temperature limits many years later after permanent closure. The results are presented in the form of correlations that span a range of package power and peak postclosure temperature, for each open-mode disposal concept, and for each timing case. Given a particular temperature limit value, the corresponding package power limit for each case can be selected for use in CALVIN and similar tools.« less

Ozone Production in Irradiated Laboratory Ices Relevant to Europa and Ganymede

NASA Astrophysics Data System (ADS)

Cooper, P. D.; Moore, M. H.; Hudson, R. L.

2005-08-01

Observations suggest ozone (O3) is present on the icy surfaces of Ganymede (1), and Rhea and Dione (2). Molecular oxygen (O2) has also been observed on Europa (3) and Ganymede (4). The formation and trapping of such molecules in ice and their subsequent transportation to a sub-surface ocean may be potentially important for sustaining astrobiological life (5). It is assumed that ozone is produced in these icy surfaces by the addition of an oxygen atom to molecular oxygen, with the latter formed by prior irradiation of the water ice. The infrared absorption band of ozone in ice at 1037 cm-1 is strong and thus makes ozone a good tracer for the presence of molecular oxygen which is difficult to detect. We will present results of water/oxygen ices irradiated with 800 keV protons and show the band position and growth of ozone with increasing radiation dose. The thermal stability of this radiolytically-produced ozone has also been measured and comparisons made to the Jovian satellites. P. Cooper is grateful for the support from the National Academies Research Associateship Program. (1) Noll, K.S., Johnson, R.E., Lane, A.L., Domingue, D.L., Weaver, H.A., Science, 273, 341-343, (1996). (2) Noll, K.S., Roush, T.L., Cruikshank, D.P., Johnson, R.E., Pendleton, Y.J., Nature, 388, 45-47, (1997). (3) Spencer, J.R., Calvin, W.M., Astron. J., 124, 3400-3403, (2002). (4) Spencer, J.R., Calvin, W.M., Person, M. J., J. Geo. Res. 100 (E9), 19049-19056 (1995). (5) Chyba, C.F., Hand, K.P., Science, 292, 2026-2027, (2001).

Abundance and Distribution of Diagnostic Carbon Fixation Genes in a Deep-Sea Hydrothermal Gradient Ecosystem

NASA Astrophysics Data System (ADS)

Blumenfeld, H. N.; Kelley, D. S.; Girguis, P. R.; Schrenk, M. O.

2010-12-01

The walls of deep-sea hydrothermal vent chimneys sustain steep thermal and chemical gradients resulting from the mixing of hot (350°C+) hydrothermal fluids with cold, oxygenated seawater. The chemical disequilibrium generated from this process has the potential to drive numerous chemolithoautotrophic metabolisms, many of which have been demonstrated to be operative in microbial pure cultures. In addition to the well-known Calvin Cycle, at least five additional pathways have been discovered including the Reverse Tricarboxylic Acid Cycle (rTCA), the Reductive Acetyl-CoA pathway, and the 3-hydroxyproprionate pathway. Most of the newly discovered pathways have been found in thermophilic and hyperthermophilic Bacteria and Archaea, which are the well represented in microbial diversity studies of hydrothermal chimney walls. However, to date, little is known about the environmental controls that impact various carbon fixation pathways. The overlap of limited microbial diversity with distinct habitat conditions in hydrothermal chimney walls provides an ideal setting to explore these relationships. Hydrothermal chimney walls from multiple structures recovered from the Juan de Fuca Ridge in the northeastern Pacific were sub-sampled and analyzed using PCR-based assays. Earlier work showed elevated microbial abundances in the outer portions of mature chimney walls, with varying ratios of Archaea to Bacteria from the outer to inner portions of the chimneys. Common phylotypes identified in these regions included Epsilonproteobacteria, Gammaproteobacteria, and Desulfurococcales. Total genomic DNA was extracted from mineralogically distinct niches within these structures and queried for genes coding key regulatory enzymes for each of the well studied carbon fixation pathways. Preliminary results show the occurrence of genes representing rTCA cycle (aclB) and methyl coenzyme A reductase (mcrA) - a proxy for the Reductive Acetyl-CoA Pathway within interior portion of mature hydrothermal chimneys. Ongoing analyses are aimed at quantifying the abundances of these diagnostic carbon fixation genes within the hydrothermal chimney gradients. These data are being compared to a broad array of contextual data to provide insight into the environmental and biological controls that may impact the distribution of the various carbon fixation pathways. Application of genomic approaches to the hydrothermal chimney ecosystem will provide insight into the microbial ecology of such structures and refine our ability to measure autotrophy in hydrothermal habitats sustained by chemical energy.

Recent Patterns of Population Change in America’s Urban Places,

DTIC Science & Technology

1980-08-01

0 00w a 0 0 3c 0 ON * 00 * Qj C) m 0 C\\ 0 N 4 N .- C𔃾-4 ..- 9 AI bo 0 0 u a, f~00 0~ ~~~ 0\\ 0 0~ 0Y w~ 0 f4 0)J CNCD G)40 & 00CC hi -C 0 22 0 00c log...Left Behind: Population Trends and Policy for Rural America," Rural Sociology, 36, 4: 449-470. Fuguitt, Glen V. and Calvin L. Beale, 1978, "Population...Redistribution in Nonmetropolitan Areas," in Sarah Mills (ed.), Population Distribution and Policy , Commission on Population Growth and the American Future

Visible-Light Organic Photocatalysis for Latent Radical-Initiated Polymerization via 2e–/1H+ Transfers: Initiation with Parallels to Photosynthesis

PubMed Central

2015-01-01

We report the latent production of free radicals from energy stored in a redox potential through a 2e–/1H+ transfer process, analogous to energy harvesting in photosynthesis, using visible-light organic photoredox catalysis (photocatalysis) of methylene blue chromophore with a sacrificial sterically hindered amine reductant and an onium salt oxidant. This enables light-initiated free-radical polymerization to continue over extended time intervals (hours) in the dark after brief (seconds) low-intensity illumination and beyond the spatial reach of light by diffusion of the metastable leuco-methylene blue photoproduct. The present organic photoredox catalysis system functions via a 2e–/1H+ shuttle mechanism, as opposed to the 1e– transfer process typical of organometallic-based and conventional organic multicomponent photoinitiator formulations. This prevents immediate formation of open-shell (radical) intermediates from the amine upon light absorption and enables the “storage” of light-energy without spontaneous initiation of the polymerization. Latent energy release and radical production are then controlled by the subsequent light-independent reaction (analogous to the Calvin cycle) between leuco-methylene blue and the onium salt oxidant that is responsible for regeneration of the organic methylene blue photocatalyst. This robust approach for photocatalysis-based energy harvesting and extended release in the dark enables temporally controlled redox initiation of polymer syntheses under low-intensity short exposure conditions and permits visible-light-mediated synthesis of polymers at least 1 order of magnitude thicker than achievable with conventional photoinitiated formulations and irradiation regimes. PMID:24786755

Visible-light organic photocatalysis for latent radical-initiated polymerization via 2e⁻/1H⁺ transfers: initiation with parallels to photosynthesis.

PubMed

Aguirre-Soto, Alan; Lim, Chern-Hooi; Hwang, Albert T; Musgrave, Charles B; Stansbury, Jeffrey W

2014-05-21

We report the latent production of free radicals from energy stored in a redox potential through a 2e(-)/1H(+) transfer process, analogous to energy harvesting in photosynthesis, using visible-light organic photoredox catalysis (photocatalysis) of methylene blue chromophore with a sacrificial sterically hindered amine reductant and an onium salt oxidant. This enables light-initiated free-radical polymerization to continue over extended time intervals (hours) in the dark after brief (seconds) low-intensity illumination and beyond the spatial reach of light by diffusion of the metastable leuco-methylene blue photoproduct. The present organic photoredox catalysis system functions via a 2e(-)/1H(+) shuttle mechanism, as opposed to the 1e(-) transfer process typical of organometallic-based and conventional organic multicomponent photoinitiator formulations. This prevents immediate formation of open-shell (radical) intermediates from the amine upon light absorption and enables the "storage" of light-energy without spontaneous initiation of the polymerization. Latent energy release and radical production are then controlled by the subsequent light-independent reaction (analogous to the Calvin cycle) between leuco-methylene blue and the onium salt oxidant that is responsible for regeneration of the organic methylene blue photocatalyst. This robust approach for photocatalysis-based energy harvesting and extended release in the dark enables temporally controlled redox initiation of polymer syntheses under low-intensity short exposure conditions and permits visible-light-mediated synthesis of polymers at least 1 order of magnitude thicker than achievable with conventional photoinitiated formulations and irradiation regimes.

Plastid proteomics for elucidating iron limited remodeling of plastid physiology in diatoms

NASA Astrophysics Data System (ADS)

Gomes, K. M.; Nunn, B. L.; Jenkins, B. D.

2016-02-01

Diatoms are important primary producers in the world's oceans and their growth is constrained in large regions by low iron availability. This low iron-induced limitation of primary production is due to the requirement for iron in components of essential metabolic pathways including key chloroplast functions such as photosynthesis and nitrate assimilation. Diatoms can bloom and accumulate high biomass during introduction of iron into low iron waters, indicating adaptations allowing for their survival in iron-limited waters and rapid growth when iron becomes more abundant. Prior studies have shown that under iron limited stress, diatoms alter plastid-specific processes including components of electron transport, size of light harvesting capacity and chlorophyll content, suggesting plastid-specific protein regulation. Due to their complex evolutionary history, resulting from a secondary endosymbiosis, knowledge regarding the complement of plastid localized proteins remains limited in comparison to other model photosynthetic organisms. While in-silico prediction of diatom protein localization provides putative candidates for plastid-localization, these analyses can be limited as most plastid prediction models were developed using plants, primary endosymbionts. In order to characterize proteins enriched in diatom chloroplast and to understand how the plastid proteome is remodeled in response to iron limitation, we used mass spectrometry based proteomics to compare plastid- enriched protein fractions from Thalassiosira pseudonana, grown in iron replete and limited conditions. These analyses show that iron stress alters regulation of major metabolic pathways in the plastid including the Calvin cycle and fatty acid synthesis. These components provide promising targets to further characterize the plastid specific response to iron limitation.

Quantitative Targeted Proteomics and Electrochromic Shift for Measuring Photosystem Content of Marine Phytoplankton

NASA Astrophysics Data System (ADS)

Brown, C. M.; Bailleul, B.; Melanson, J. R.; Campbell, D. A.; Cockshutt, A. M.; Cardol, P.

2016-02-01

Abundance and stoichiometry data for the photosystems, the intersystem electron transport complexes and the Calvin cycle enzymes are rich in information about light and nutrient acclimation. Quantifying these complexes is essential for understanding limitations on and capacities for photosynthesis. Targeted quantitative immunodetections of conserved subunits (eg. PsbA for PSII; PsaC for PSI) are becoming an established method for absolute measurement of these complexes. An advantage of protein measurements is that they can be done with non-living flash-frozen samples and processed post-field. A pitfall of physical versus functional measures is that in some scenarios, such as during photoinhibition of photosystem II (PSII), physical and functional measures give different values, but such disparities are often meaningful, informing targeted studies of regulation, repair and enzyme kinetics. Electrochromic Shift (ECS) is an alternative, fast and noninvasive method which can be exploited to determine functional PSI:PSII ratios in living cells. The basis for ECS is that pigments in the photosynthetic membrane exhibit a shift in their absorption spectra when the electric component of the proton motive force is generated across the membrane in the light. Cross-validation of methods by independent measures builds confidence in results from both approaches and can be useful for ground truthing of underway or high-throughput optical measurements or functional measurements from bioassays. We present comparative data from immunoquantitation and ECS for an array of diatom taxa. The physical data fall within established ranges. The basis for similarities and disparities in the photosystem stoichiometries between the methods are discussed.

Genetic improvement of leaf photosynthesis and intrinsic water use efficiency in C3 plants: Why so much little success?

PubMed

Flexas, J

2016-10-01

There is an urgent need for simultaneously increasing photosynthesis/yields and water use efficiency (WUE) in C3 crops. Potentially, this can be achieved by genetic manipulation of the key traits involved. However, despite significant efforts in the past two decades very limited success has been achieved. Here I argue that this is mostly due to the fact that single gene/single trait approaches have been used thus far. Photosynthesis models demonstrate that only limited improving of photosynthesis can be expected by large improvements of any of its single limiting factors, i.e. stomatal conductance, mesophyll conductance, and the biochemical capacity for photosynthesis, the latter co-limited by Rubisco and the orchestrated activity of thylakoid electron transport and the Calvin cycle enzymes. Accordingly, only limited improvements of photosynthesis have been obtained by genetic manipulation of any of these single factors. In addition, improving photosynthesis by genetic manipulation in general reduced WUE, and vice-versa, and in many cases pleiotropic effects appear that cancel out some of the expected benefits. I propose that success in genetic manipulation for simultaneous improvement of photosynthesis and WUE efficiency may take longer than suggested in previous reports, and that it can be achieved only by joint projects addressing multi-gene manipulation for simultaneous alterations of all the limiting factors of photosynthesis, including the often neglected phloem capacity for loading and transport the expected surplus of carbohydrates in plants with improved photosynthesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Symbiodinium sp. cells produce light-induced intra- and extracellular singlet oxygen, which mediates photodamage of the photosynthetic apparatus and has the potential to interact with the animal host in coral symbiosis.

PubMed

Rehman, Ateeq Ur; Szabó, Milán; Deák, Zsuzsanna; Sass, László; Larkum, Anthony; Ralph, Peter; Vass, Imre

2016-10-01

Coral bleaching is an important environmental phenomenon, whose mechanism has not yet been clarified. The involvement of reactive oxygen species (ROS) has been implicated, but direct evidence of what species are involved, their location and their mechanisms of production remains unknown. Histidine-mediated chemical trapping and singlet oxygen sensor green (SOSG) were used to detect intra- and extracellular singlet oxygen ((1) O2 ) in Symbiodinium cultures. Inhibition of the Calvin-Benson cycle by thermal stress or high light promotes intracellular (1) O2 formation. Histidine addition, which decreases the amount of intracellular (1) O2 , provides partial protection against photosystem II photoinactivation and chlorophyll (Chl) bleaching. (1) O2 production also occurs in cell-free medium of Symbiodinium cultures, an effect that is enhanced under heat and light stress and can be attributed to the excretion of (1) O2 -sensitizing metabolites from the cells. Confocal microscopy imaging using SOSG showed most extracellular (1) O2 around the cell surface, but it is also produced across the medium distant from the cells. We demonstrate, for the first time, both intra- and extracellular (1) O2 production in Symbiodinium cultures. Intracellular (1) O2 is associated with photosystem II photodamage and pigment bleaching, whereas extracellular (1) O2 has the potential to mediate the breakdown of symbiotic interaction between zooxanthellae and their animal host during coral bleaching. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

A function-based screen for seeking RubisCO active clones from metagenomes: novel enzymes influencing RubisCO activity.

PubMed

Böhnke, Stefanie; Perner, Mirjam

2015-03-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is a key enzyme of the Calvin cycle, which is responsible for most of Earth's primary production. Although research on RubisCO genes and enzymes in plants, cyanobacteria and bacteria has been ongoing for years, still little is understood about its regulation and activation in bacteria. Even more so, hardly any information exists about the function of metagenomic RubisCOs and the role of the enzymes encoded on the flanking DNA owing to the lack of available function-based screens for seeking active RubisCOs from the environment. Here we present the first solely activity-based approach for identifying RubisCO active fosmid clones from a metagenomic library. We constructed a metagenomic library from hydrothermal vent fluids and screened 1056 fosmid clones. Twelve clones exhibited RubisCO activity and the metagenomic fragments resembled genes from Thiomicrospira crunogena. One of these clones was further analyzed. It contained a 35.2 kb metagenomic insert carrying the RubisCO gene cluster and flanking DNA regions. Knockouts of twelve genes and two intergenic regions on this metagenomic fragment demonstrated that the RubisCO activity was significantly impaired and was attributed to deletions in genes encoding putative transcriptional regulators and those believed to be vital for RubisCO activation. Our new technique revealed a novel link between a poorly characterized gene and RubisCO activity. This screen opens the door to directly investigating RubisCO genes and respective enzymes from environmental samples.

Rubisco mutants of Chlamydomonas reinhardtii enhance photosynthetic hydrogen production.

PubMed

Pinto, T S; Malcata, F X; Arrabaça, J D; Silva, J M; Spreitzer, R J; Esquível, M G

2013-06-01

Molecular hydrogen (H2) is an ideal fuel characterized by high enthalpy change and lack of greenhouse effects. This biofuel can be released by microalgae via reduction of protons to molecular hydrogen catalyzed by hydrogenases. The main competitor for the reducing power required by the hydrogenases is the Calvin cycle, and rubisco plays a key role therein. Engineered Chlamydomonas with reduced rubisco levels, activity and stability was used as the basis of this research effort aimed at increasing hydrogen production. Biochemical monitoring in such metabolically engineered mutant cells proceeded in Tris/acetate/phosphate culture medium with S-depletion or repletion, both under hypoxia. Photosynthetic activity, maximum photochemical efficiency, chlorophyll and protein levels were all measured. In addition, expression of rubisco, hydrogenase, D1 and Lhcb were investigated, and H2 was quantified. At the beginning of the experiments, rubisco increased followed by intense degradation. Lhcb proteins exhibited monomeric isoforms during the first 24 to 48 h, and D1 displayed sensitivity under S-depletion. Rubisco mutants exhibited a significant decrease in O2 evolution compared with the control. Although the S-depleted medium was much more suitable than its complete counterpart for H2 production, hydrogen release was observed also in sealed S-repleted cultures of rubisco mutated cells under low-moderate light conditions. In particular, the rubisco mutant Y67A accounted for 10-15-fold higher hydrogen production than the wild type under the same conditions and also displayed divergent metabolic parameters. These results indicate that rubisco is a promising target for improving hydrogen production rates in engineered microalgae.

Copper stress-induced changes in leaf soluble proteome of Cu-sensitive and tolerant Agrostis capillaris L. populations.

PubMed

Hego, Elena; Vilain, Sébastien; Barré, Aurélien; Claverol, Stéphane; Dupuy, Jean-William; Lalanne, Céline; Bonneu, Marc; Plomion, Christophe; Mench, Michel

2016-05-01

Changes in leaf soluble proteome were explored in 3-month-old plants of metallicolous (M) and nonmetallicolous (NM) Agrostis capillaris L. populations exposed to increasing Cu concentrations (1-50 μM) to investigate molecular mechanisms underlying plant responses to Cu excess and tolerance of M plants. Plants were cultivated on perlite (CuSO4 spiked-nutrient solution). Soluble proteins, extracted by the trichloroacetic acid/acetone procedure, were separated with 2-DE (linear 4-7 pH gradient). Analysis of CCB-stained gels (PDQuest) reproducibly detected 214 spots, and 64 proteins differentially expressed were identified using LC-MS/MS. In both populations, Cu excess impacted both light-dependent (OEE, cytochrome b6-f complex, and chlorophyll a-b binding protein), and -independent (RuBisCO) photosynthesis reactions, more intensively in NM leaves (ferredoxin-NADP reductase and metalloprotease FTSH2). In both populations, upregulation of isocitrate dehydrogenase and cysteine/methionine synthases respectively suggested increased isocitrate oxidation and enhanced need for S-containing amino-acids, likely for chelation and detoxification. In NM leaves, an increasing need for energetic compounds was indicated by the stimulation of ATPases, glycolysis, pentose phosphate pathway, and Calvin cycle enzymes; impacts on protein metabolism and oxidative stress increase were respectively suggested by the rise of chaperones and redox enzymes. Overexpression of a HSP70 may be pivotal for M Cu tolerance by protecting protein metabolism. All MS data have been deposited in the ProteomeXchange with the dataset identifier PXD001930 (http//proteomecentral.proteomexchange.org/dataset/PXD001930). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copper-Deficiency in Brassica napus Induces Copper Remobilization, Molybdenum Accumulation and Modification of the Expression of Chloroplastic Proteins

PubMed Central

Billard, Vincent; Ourry, Alain; Maillard, Anne; Garnica, Maria; Coquet, Laurent; Jouenne, Thierry; Cruz, Florence; Garcia-Mina, José-Maria; Yvin, Jean-Claude; Etienne, Philippe

2014-01-01

During the last 40 years, crop breeding has strongly increased yields but has had adverse effects on the content of micronutrients, such as Fe, Mg, Zn and Cu, in edible products despite their sufficient supply in most soils. This suggests that micronutrient remobilization to edible tissues has been negatively selected. As a consequence, the aim of this work was to quantify the remobilization of Cu in leaves of Brassica napus L. during Cu deficiency and to identify the main metabolic processes that were affected so that improvements can be achieved in the future. While Cu deficiency reduced oilseed rape growth by less than 19% compared to control plants, Cu content in old leaves decreased by 61.4%, thus demonstrating a remobilization process between leaves. Cu deficiency also triggered an increase in Cu transporter expression in roots (COPT2) and leaves (HMA1), and more surprisingly, the induction of the MOT1 gene encoding a molybdenum transporter associated with a strong increase in molybdenum (Mo) uptake. Proteomic analysis of leaves revealed 33 proteins differentially regulated by Cu deficiency, among which more than half were located in chloroplasts. Eleven differentially expressed proteins are known to require Cu for their synthesis and/or activity. Enzymes that were located directly upstream or downstream of Cu-dependent enzymes were also differentially expressed. The overall results are then discussed in relation to remobilization of Cu, the interaction between Mo and Cu that occurs through the synthesis pathway of Mo cofactor, and finally their putative regulation within the Calvin cycle and the chloroplastic electron transport chain. PMID:25333918

Algal photosynthesis as the primary driver for a sustainable development in energy, feed, and food production.

PubMed

Anemaet, Ida G; Bekker, Martijn; Hellingwerf, Klaas J

2010-11-01

High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, one uses renewable resources. Sunlight is used for the conversion of water and CO₂ into biomass. Two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. Both, however, exacerbate other problems, including regional nutrient balancing and the world's food supply, and suffer from the modest efficiency of photosynthesis. Maximizing the efficiency of natural and engineered photosynthesis is therefore of utmost importance. Algal photosynthesis is the system of choice for this particularly for energy applications. Complete conversion of CO₂ into biomass is not necessary for this. Innovative methods of synthetic biology allow one to combine photosynthetic and fermentative metabolism via the so-called Photanol approach to form biofuel directly from Calvin cycle intermediates through use of the naturally transformable cyanobacterium Synechocystis sp. PCC 6803. Beyond providing transport energy and chemical feedstocks, photosynthesis will continue to be used for food and feed applications. Also for this application, arguments of efficiency will become more and more important as the size of the world population continues to increase. Photosynthetic cells can be used for food applications in various innovative forms, e.g., as a substitute for the fish proteins in the diet supplied to carnivorous fish or perhaps--after acid hydrolysis--as a complex, animal-free serum for growth of mammalian cells in vitro.

Algal Photosynthesis as the Primary Driver for a Sustainable Development in Energy, Feed, and Food Production

PubMed Central

Anemaet, Ida G.; Bekker, Martijn

2010-01-01

High oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. Photosynthetic biofuel production represents one of these since for this, one uses renewable resources. Sunlight is used for the conversion of water and CO2 into biomass. Two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. Both, however, exacerbate other problems, including regional nutrient balancing and the world's food supply, and suffer from the modest efficiency of photosynthesis. Maximizing the efficiency of natural and engineered photosynthesis is therefore of utmost importance. Algal photosynthesis is the system of choice for this particularly for energy applications. Complete conversion of CO2 into biomass is not necessary for this. Innovative methods of synthetic biology allow one to combine photosynthetic and fermentative metabolism via the so-called Photanol approach to form biofuel directly from Calvin cycle intermediates through use of the naturally transformable cyanobacterium Synechocystis sp. PCC 6803. Beyond providing transport energy and chemical feedstocks, photosynthesis will continue to be used for food and feed applications. Also for this application, arguments of efficiency will become more and more important as the size of the world population continues to increase. Photosynthetic cells can be used for food applications in various innovative forms, e.g., as a substitute for the fish proteins in the diet supplied to carnivorous fish or perhaps—after acid hydrolysis—as a complex, animal-free serum for growth of mammalian cells in vitro. PMID:20640935

Characterization of Chloroplastic Fructose 1,6-Bisphosphate Aldolases as Lysine-methylated Proteins in Plants*

PubMed Central

Mininno, Morgane; Brugière, Sabine; Pautre, Virginie; Gilgen, Annabelle; Ma, Sheng; Ferro, Myriam; Tardif, Marianne; Alban, Claude; Ravanel, Stéphane

2012-01-01

In pea (Pisum sativum), the protein-lysine methyltransferase (PsLSMT) catalyzes the trimethylation of Lys-14 in the large subunit (LS) of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the enzyme catalyzing the CO2 fixation step during photosynthesis. Homologs of PsLSMT, herein referred to as LSMT-like enzymes, are found in all plant genomes, but methylation of LS Rubisco is not universal in the plant kingdom, suggesting a species-specific protein substrate specificity of the methyltransferase. In this study, we report the biochemical characterization of the LSMT-like enzyme from Arabidopsis thaliana (AtLSMT-L), with a focus on its substrate specificity. We show that, in Arabidopsis, LS Rubisco is not naturally methylated and that the physiological substrates of AtLSMT-L are chloroplastic fructose 1,6-bisphosphate aldolase isoforms. These enzymes, which are involved in the assimilation of CO2 through the Calvin cycle and in chloroplastic glycolysis, are trimethylated at a conserved lysyl residue located close to the C terminus. Both AtLSMT-L and PsLSMT are able to methylate aldolases with similar kinetic parameters and product specificity. Thus, the divergent substrate specificity of LSMT-like enzymes from pea and Arabidopsis concerns only Rubisco. AtLSMT-L is able to interact with unmethylated Rubisco, but the complex is catalytically unproductive. Trimethylation does not modify the kinetic properties and tetrameric organization of aldolases in vitro. The identification of aldolases as methyl proteins in Arabidopsis and other species like pea suggests a role of protein lysine methylation in carbon metabolism in chloroplasts. PMID:22547063

Metabolic and Transcriptional Analysis of Durum Wheat Responses to Elevated CO2 at Low and High Nitrate Supply.

PubMed

Vicente, Rubén; Pérez, Pilar; Martínez-Carrasco, Rafael; Feil, Regina; Lunn, John E; Watanabe, Mutsumi; Arrivault, Stephanie; Stitt, Mark; Hoefgen, Rainer; Morcuende, Rosa

2016-10-01

Elevated [CO 2 ] (eCO 2 ) can lead to photosynthetic acclimation and this is often intensified by low nitrogen (N). Despite intensive studies of plant responses to eCO 2 , the regulation mechanism of primary metabolism at the whole-plant level in interaction with [Formula: see text] supply remains unclear. We examined the metabolic and transcriptional responses triggered by eCO 2 in association with physiological-biochemical traits in flag leaves and roots of durum wheat grown hydroponically in ambient and elevated [CO 2 ] with low (LN) and high (HN) [Formula: see text] supply. Multivariate analysis revealed a strong interaction between eCO 2 and [Formula: see text] supply. Photosynthetic acclimation induced by eCO 2 in LN plants was accompanied by an increase in biomass and carbohydrates, and decreases of leaf organic N per unit area, organic acids, inorganic ions, Calvin-Benson cycle intermediates, Rubisco, nitrate reductase activity, amino acids and transcripts for N metabolism, particularly in leaves, whereas [Formula: see text] uptake was unaffected. In HN plants, eCO 2 did not decrease photosynthetic capacity or leaf organic N per unit area, but induced transcripts for N metabolism, especially in roots. In conclusion, the photosynthetic acclimation in LN plants was associated with an inhibition of leaf [Formula: see text] assimilation, whereas up-regulation of N metabolism in roots could have mitigated the acclimatory effect of eCO 2 in HN plants. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holland, Steven C.; Artier, Juliana; Miller, Neil T.

Genetic engineering of photosynthetic organisms typically redirects native metabolism towards desirable products, which thereby represent new metabolic sinks. There is limited information on how these modifications impact the evolved mechanisms of photosynthetic energy metabolism and cellular growth. Two engineered strains of Synechocystis sp. PCC 6803 with altered carbon sink capacity were assayed for their photosynthetic and CO 2 concentrating mechanism properties in conditions of high and low inorganic carbon (Ci) availability. In the ΔglgC mutant, glycogen cannot be synthesized and a carbon sink pathway has been effectively removed. The JU547 strain has been engineered by integration of the Pseudomonas syringaemore » ethylene forming enzyme and provides a new sink. When cultured under high carbon conditions, ΔglgC displayed diminished photochemical efficiency, a more reduced NADPH pool, delayed initiation of the Calvin-Benson-Bassham cycle, and impairment of linear and cyclic electron flows. It also exhibited a large decrease in photochemical quenching indicative of the accumulation of Q A-, normally associated with a reduced PQ pool, but appears instead to be the result of an undefined dissipative mechanism to spill excess energy. In the case of carbon sink integration, JU547 displayed slightly more oxidized PQ and NADPH pools and increased rates of cyclic electron flow and an enhanced demand for inorganic carbon as suggested by increase in the expression of the bicarbonate transporter, SbtA. Overall, the results highlight the importance of the native regulatory network of autotrophic metabolism in governing photosynthetic performance and provide cogent examples of both predicable and difficult to predict phenotypic consequences upon installation of new pathways in autotrophs.« less

Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps.

PubMed

Portail, Marie; Olu, Karine; Dubois, Stanislas F; Escobar-Briones, Elva; Gelinas, Yves; Menot, Lénaick; Sarrazin, Jozée

In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to partly release the competitive pressure within communities of low fluid-flux habitats. Finally, ecosystem functioning in vents and seeps was highly similar despite environmental differences (e.g. physico-chemistry, dominant basal sources) suggesting that ecological niches are not specifically linked to the nature of fluids. This comparison of seep and vent functioning in the Guaymas basin thus provides further supports to the hypothesis of continuity among deep-sea chemosynthetic ecosystems.

Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps

PubMed Central

Olu, Karine; Dubois, Stanislas F.; Escobar-Briones, Elva; Gelinas, Yves; Menot, Lénaick; Sarrazin, Jozée

2016-01-01

In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to partly release the competitive pressure within communities of low fluid-flux habitats. Finally, ecosystem functioning in vents and seeps was highly similar despite environmental differences (e.g. physico-chemistry, dominant basal sources) suggesting that ecological niches are not specifically linked to the nature of fluids. This comparison of seep and vent functioning in the Guaymas basin thus provides further supports to the hypothesis of continuity among deep-sea chemosynthetic ecosystems. PMID:27683216

Culture-Independent Identification of Manganese-Oxidizing Genes from Deep-Sea Hydrothermal Vent Chemoautotrophic Ferromanganese Microbial Communities Using a Metagenomic Approach

NASA Astrophysics Data System (ADS)

Davis, R.; Tebo, B. M.

2013-12-01

Microbial activity has long been recognized as being important to the fate of manganese (Mn) in hydrothermal systems, yet we know very little about the organisms that catalyze Mn oxidation, the mechanisms by which Mn is oxidized or the physiological function that Mn oxidation serves in these hydrothermal systems. Hydrothermal vents with thick ferromanganese microbial mats and Mn oxide-coated rocks observed throughout the Pacific Ring of Fire are ideal models to study the mechanisms of microbial Mn oxidation, as well as primary productivity in these metal-cycling ecosystems. We sampled ferromanganese microbial mats from Vai Lili Vent Field (Tmax=43°C) located on the Eastern Lau Spreading Center and Mn oxide-encrusted rhyolytic pumice (4°C) from Niua South Seamount on the Tonga Volcanic Arc. Metagenomic libraries were constructed and assembled from these samples and key genes known to be involved in Mn oxidation and carbon fixation pathways were identified in the reconstructed genomes. The Vai Lili metagenome assembled to form 121,157 contiguous sequences (contigs) greater than 1000bp in length, with an N50 of 8,261bp and a total metagenome size of 593 Mbp. Contigs were binned using an emergent self-organizing map of tetranucleotide frequencies. Putative homologs of the multicopper Mn-oxidase MnxG were found in the metagenome that were related to both the Pseudomonas-like and Bacillus-like forms of the enzyme. The bins containing the Pseudomonas-like mnxG genes are most closely related to uncultured Deltaproteobacteria and Chloroflexi. The Deltaproteobacteria bin appears to be an obligate anaerobe with possible chemoautotrophic metabolisms, while the Chloroflexi appears to be a heterotrophic organism. The metagenome from the Mn-stained pumice was assembled into 122,092 contigs greater than 1000bp in length with an N50 of 7635 and a metagenome size of 385 Mbp. Both forms of mnxG genes are present in this metagenome as well as the genes encoding the putative Mn oxidases McoA and MopA. The greater diversity of Mn oxidase pathways in this metagenome suggests a more diverse Mn oxidizing microbial community in the cold pumice sample. Key enzymes for four of the six known carbon fixation pathways (the Calvin Cycle, the reductive TCA cycle, the Wood-Ljungdahl pathway, and the 3-hydroxypropionate/4-hydroxybutyrate Cycle) were also identified in both samples indicating primary production occurs via a diverse community of carbon fixing organisms. Together, these samples contain active, diverse populations of Mn oxidizing bacteria living in association with microbial communities supported by chemoautotrophic carbon fixation.

Characterization of two transketolases encoded on the chromosome and the plasmid pBM19 of the facultative ribulose monophosphate cycle methylotroph Bacillus methanolicus

PubMed Central

2014-01-01

Background Transketolase (TKT) is a key enzyme of the pentose phosphate pathway (PPP), the Calvin cycle and the ribulose monophosphate (RuMP) cycle. Bacillus methanolicus is a facultative RuMP pathway methylotroph. B. methanolicus MGA3 harbors two genes putatively coding for TKTs; one located on the chromosome (tkt C ) and one located on the natural occurring plasmid pBM19 (tkt P ). Results Both enzymes were produced in recombinant Escherichia coli, purified and shown to share similar biochemical parameters in vitro. They were found to be active as homotetramers and require thiamine pyrophosphate for catalytic activity. The inactive apoform of the TKTs, yielded by dialysis against buffer containing 10 mM EDTA, could be reconstituted most efficiently with Mn2+ and Mg2+. Both TKTs were thermo stable at physiological temperature (up to 65°C) with the highest activity at neutral pH. Ni2+, ATP and ADP significantly inhibited activity of both TKTs. Unlike the recently characterized RuMP pathway enzymes fructose 1,6-bisphosphate aldolase (FBA) and fructose 1,6-bisphosphatase/sedoheptulose 1,7-bisphosphatase (FBPase/SBPase) from B. methanolicus MGA3, both TKTs exhibited similar kinetic parameters although they only share 76% identical amino acids. The kinetic parameters were determined for the reaction with the substrates xylulose 5-phosphate (TKTC: kcat/KM: 264 s-1 mM-1; TKTP: kcat/KM: 231 s-1 mM) and ribulose 5-phosphate (TKTC: kcat/KM: 109 s-1 mM; TKTP: kcat/KM: 84 s-1 mM) as well as for the reaction with the substrates glyceraldehyde 3-phosphate (TKTC: kcat/KM: 108 s-1 mM; TKTP: kcat/KM: 71 s-1 mM) and fructose 6-phosphate (TKTC kcat/KM: 115 s-1 mM; TKTP: kcat/KM: 448 s-1 mM). Conclusions Based on the kinetic parameters no major TKT of B. methanolicus could be determined. Increased expression of tkt P , but not of tkt C during growth with methanol [J Bacteriol 188:3063–3072, 2006] argues for TKTP being the major TKT relevant in the RuMP pathway. Neither TKT exhibited activity as dihydroxyacetone synthase, as found in methylotrophic yeast, or as the evolutionary related 1-deoxyxylulose-5-phosphate synthase. The biological significance of the two TKTs for B. methanolicus methylotrophy is discussed. PMID:24405865

Characterization of two transketolases encoded on the chromosome and the plasmid pBM19 of the facultative ribulose monophosphate cycle methylotroph Bacillus methanolicus.

PubMed

Markert, Benno; Stolzenberger, Jessica; Brautaset, Trygve; Wendisch, Volker F

2014-01-09

Transketolase (TKT) is a key enzyme of the pentose phosphate pathway (PPP), the Calvin cycle and the ribulose monophosphate (RuMP) cycle. Bacillus methanolicus is a facultative RuMP pathway methylotroph. B. methanolicus MGA3 harbors two genes putatively coding for TKTs; one located on the chromosome (tkt(C)) and one located on the natural occurring plasmid pBM19 (tkt(P)). Both enzymes were produced in recombinant Escherichia coli, purified and shown to share similar biochemical parameters in vitro. They were found to be active as homotetramers and require thiamine pyrophosphate for catalytic activity. The inactive apoform of the TKTs, yielded by dialysis against buffer containing 10 mM EDTA, could be reconstituted most efficiently with Mn(2+) and Mg(2+). Both TKTs were thermo stable at physiological temperature (up to 65°C) with the highest activity at neutral pH. Ni(2+), ATP and ADP significantly inhibited activity of both TKTs. Unlike the recently characterized RuMP pathway enzymes fructose 1,6-bisphosphate aldolase (FBA) and fructose 1,6-bisphosphatase/sedoheptulose 1,7-bisphosphatase (FBPase/SBPase) from B. methanolicus MGA3, both TKTs exhibited similar kinetic parameters although they only share 76% identical amino acids. The kinetic parameters were determined for the reaction with the substrates xylulose 5-phosphate (TKT(C): kcat/KM: 264 s(-1) mM(-1); TKT(P): kcat/KM: 231 s(-1) mM) and ribulose 5-phosphate (TKT(C): kcat/KM: 109 s(-1) mM; TKT(P): kcat/KM: 84 s(-1) mM) as well as for the reaction with the substrates glyceraldehyde 3-phosphate (TKT(C): kcat/KM: 108 s(-1) mM; TKT(P): kcat/KM: 71 s(-1) mM) and fructose 6-phosphate (TKT(C) kcat/KM: 115 s(-1) mM; TKT(P): kcat/KM: 448 s(-1) mM). Based on the kinetic parameters no major TKT of B. methanolicus could be determined. Increased expression of tkt(P), but not of tkt(C) during growth with methanol [J Bacteriol 188:3063-3072, 2006] argues for TKT(P) being the major TKT relevant in the RuMP pathway. Neither TKT exhibited activity as dihydroxyacetone synthase, as found in methylotrophic yeast, or as the evolutionary related 1-deoxyxylulose-5-phosphate synthase. The biological significance of the two TKTs for B. methanolicus methylotrophy is discussed.

Identification of nuclear genes controlling chlorophyll synthesis in barley by RNA-seq.

PubMed

Shmakov, Nickolay A; Vasiliev, Gennadiy V; Shatskaya, Natalya V; Doroshkov, Alexey V; Gordeeva, Elena I; Afonnikov, Dmitry A; Khlestkina, Elena K

2016-11-16

Albinism in plants is characterized by lack of chlorophyll and results in photosynthesis impairment, abnormal plant development and premature death. These abnormalities are frequently encountered in interspecific crosses and tissue culture experiments. Analysis of albino mutant phenotypes with full or partial chlorophyll deficiency can shed light on genetic determinants and molecular mechanisms of albinism. Here we report analysis of RNA-seq transcription profiling of barley (Hordeum vulgare L.) near-isogenic lines, one of which is a carrier of mutant allele of the Alm gene for albino lemma and pericarp phenotype (line i:BwAlm). 1221 genome fragments have statistically significant changes in expression levels between lines i:BwAlm and Bowman, with 148 fragments having increased expression levels in line i:BwAlm, and 1073 genome fragments, including 42 plastid operons, having decreased levels of expression in line i:BwAlm. We detected functional dissimilarity between genes with higher and lower levels of expression in i:BwAlm line. Genes with lower level of expression in the i:BwAlm line are mostly associated with photosynthesis and chlorophyll synthesis, while genes with higher expression level are functionally associated with vesicle transport. Differentially expressed genes are shown to be involved in several metabolic pathways; the largest fraction of such genes was observed for the Calvin-Benson-Bassham cycle. Finally, de novo assembly of transcriptome contains several transcripts, not annotated in current H. vulgare genome version. Our results provide the new information about genes which could be involved in formation of albino lemma and pericarp phenotype. They demonstrate the interplay between nuclear and chloroplast genomes in this physiological process.

Increased Photochemical Efficiency in Cyanobacteria via an Engineered Sucrose Sink.

PubMed

Abramson, Bradley W; Kachel, Benjamin; Kramer, David M; Ducat, Daniel C

2016-12-01

In plants, a limited capacity to utilize or export the end-products of the Calvin-Benson cycle (CB) from photosynthetically active source cells to non-photosynthetic sink cells can result in reduced carbon capture and photosynthetic electron transport (PET), and lowered photochemical efficiency. The down-regulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed 'sink limitation'. Recently, several cyanobacterial and algal strains engineered to overproduce target metabolites have exhibited increased photochemistry, suggesting that possible source-sink regulatory mechanisms may be involved. We directly examined photochemical properties following induction of a heterologous sucrose 'sink' in the unicellular cyanobacterium Synechococcus elongatus PCC 7942. We show that total photochemistry increases proportionally to the experimentally controlled rate of sucrose export. Importantly, the quantum yield of PSII (ΦII) increases in response to sucrose export while the PET chain becomes more oxidized from less PSI acceptor-side limitation, suggesting increased CB activity and a decrease in sink limitation. Enhanced photosynthetic activity and linear electron flow are detectable within hours of induction of the heterologous sink and are independent of pigmentation alterations or the ionic/osmotic effects of the induction system. These observations provide direct evidence that secretion of heterologous carbon bioproducts can be used as an alternative approach to improve photosynthetic efficiency, presumably by by-passing sink limitation. Our results also suggest that engineered microalgal production strains are valuable alternative models for examining photosynthetic sink limitation because they enable greater control and monitoring of metabolite fluxes relative to plants. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Relationships between the Efficiencies of Photosystems I and II and Stromal Redox State in CO2-Free Air 1

PubMed Central

Harbinson, Jeremy; Foyer, Christine H.

1991-01-01

The responses of the efficiencies of photosystems I and II, stromal redox state (as indicated by NADP-malate dehydrogenase activation state), and activation of the Benson-Calvin cycle enzymes ribulose 1,5-bisphosphate carboxylase and fructose 1,6-bisphosphatase to varying irradiance were measured in pea (Pisum sativum L.) leaves operating close to the CO2 compensation point. A comparison of the relationships among these parameters obtained from leaves in air was made with those obtained when the leaves were maintained in air from which the CO2 had been removed. P700 was more oxidized at any measured irradiance in CO2-free air than in air. The relationship between the quantum efficiencies of the photosystems in CO2-free air was distinctly curvilinear in contrast to the predominantly linear relationship obtained with leaves in air. This nonlinearity may be consistent with the operation of cyclic electron flow around photosystem I because the quantum efficiency of photosystem II was much more restricted than the quantum efficiency of photosystem I. In CO2-free air, measured NADP-malate dehydrogenase activities varied considerably at low irradiances. However, at high irradiance the activity of the enzyme was low, implying that the stroma was oxidized. In contrast, fructose-1,6-bisphosphatase activities tended to increase with increasing electron flux through the photosystems. Ribulose-1,5-bisphosphate carboxylase activity remained relatively constant with respect to irradiance in CO2-free air, with an activation state 50% of maximum. We conclude that, at the CO2 compensation point and high irradiance, low redox states are favored and that cyclic electron flow may be substantial. These two features may be the requirements necessary to trigger and maintain the dissipative processes in the thylakoid membrane. PMID:16668401

Impacts of genetically engineered alterations in carbon sink pathways on photosynthetic performance

DOE PAGES

Holland, Steven C.; Artier, Juliana; Miller, Neil T.; ...

2016-10-05

Genetic engineering of photosynthetic organisms typically redirects native metabolism towards desirable products, which thereby represent new metabolic sinks. There is limited information on how these modifications impact the evolved mechanisms of photosynthetic energy metabolism and cellular growth. Two engineered strains of Synechocystis sp. PCC 6803 with altered carbon sink capacity were assayed for their photosynthetic and CO 2 concentrating mechanism properties in conditions of high and low inorganic carbon (Ci) availability. In the ΔglgC mutant, glycogen cannot be synthesized and a carbon sink pathway has been effectively removed. The JU547 strain has been engineered by integration of the Pseudomonas syringaemore » ethylene forming enzyme and provides a new sink. When cultured under high carbon conditions, ΔglgC displayed diminished photochemical efficiency, a more reduced NADPH pool, delayed initiation of the Calvin-Benson-Bassham cycle, and impairment of linear and cyclic electron flows. It also exhibited a large decrease in photochemical quenching indicative of the accumulation of Q A-, normally associated with a reduced PQ pool, but appears instead to be the result of an undefined dissipative mechanism to spill excess energy. In the case of carbon sink integration, JU547 displayed slightly more oxidized PQ and NADPH pools and increased rates of cyclic electron flow and an enhanced demand for inorganic carbon as suggested by increase in the expression of the bicarbonate transporter, SbtA. Overall, the results highlight the importance of the native regulatory network of autotrophic metabolism in governing photosynthetic performance and provide cogent examples of both predicable and difficult to predict phenotypic consequences upon installation of new pathways in autotrophs.« less

RuBisCO depletion improved proteome coverage of cold responsive S-nitrosylated targets in Brassica juncea

PubMed Central

Sehrawat, Ankita; Abat, Jasmeet K.; Deswal, Renu

2013-01-01

Although in the last few years good number of S-nitrosylated proteins are identified but information on endogenous targets is still limiting. Therefore, an attempt is made to decipher NO signaling in cold treated Brassica juncea seedlings. Treatment of seedlings with substrate, cofactor and inhibitor of Nitric-oxide synthase and nitrate reductase (NR), indicated NR mediated NO biosynthesis in cold. Analysis of the in vivo thiols showed depletion of low molecular weight thiols and enhancement of available protein thiols, suggesting redox changes. To have a detailed view, S-nitrosylation analysis was done using biotin switch technique (BST) and avidin-affinity chromatography. Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is S-nitrosylated and therefore, is identified as target repeatedly due to its abundance. It also competes out low abundant proteins which are important NO signaling components. Therefore, RuBisCO was removed (over 80%) using immunoaffinity purification. Purified S-nitrosylated RuBisCO depleted proteins were resolved on 2-D gel as 110 spots, including 13 new, which were absent in the crude S-nitrosoproteome. These were identified by nLC-MS/MS as thioredoxin, fructose biphosphate aldolase class I, myrosinase, salt responsive proteins, peptidyl-prolyl cis-trans isomerase and malate dehydrogenase. Cold showed differential S-nitrosylation of 15 spots, enhanced superoxide dismutase activity (via S-nitrosylation) and promoted the detoxification of superoxide radicals. Increased S-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase sedoheptulose-biphosphatase, and fructose biphosphate aldolase, indicated regulation of Calvin cycle by S-nitrosylation. The results showed that RuBisCO depletion improved proteome coverage and provided clues for NO signaling in cold. PMID:24032038

Comparative shoot proteome analysis of two potato (Solanum tuberosum L.) genotypes contrasting in nitrogen deficiency responses in vitro.

PubMed

Meise, Philipp; Jozefowicz, Anna Maria; Uptmoor, Ralf; Mock, Hans-Peter; Ordon, Frank; Schum, Annegret

2017-08-23

Aiming at a better understanding of the physiological and biochemical background of nitrogen use efficiency, alterations in the shoot proteome under N-deficiency were investigated in two contrasting potato genotypes grown in vitro with 60 and 7.5mM N, respectively. A gel based proteomic approach was applied to identify candidate proteins associated with genotype specific responses to N-deficiency. 21% of the detected proteins differed in abundance between the two genotypes. Between control and N-deficiency conditions 19.5% were differentially accumulated in the sensitive and 15% in the tolerant genotype. 93% of the highly N-deficiency responsive proteins were identified by MALDI TOF/TOF mass spectrometry. The major part was associated with photosynthesis, carbohydrate metabolism, stress response and regulation. Differential accumulation of enzymes involved in the Calvin cycle and glycolysis suggest activation of alternative carbohydrate pathways. In the tolerant genotype, increased abundance under N-deficiency was also found for enzymes involved in chlorophyll synthesis and stability of enzymes, which increase photosynthetic carbon fixation efficiency. Out of a total of 106 differentially abundant proteins, only eight were detected in both genotypes. Our findings suggest that mutually responsive proteins reflect universal stress responses while adaptation to N-deficiency in metabolic pathways is more genotype specific. Nitrogen losses from arable farm land considerably contribute to environmental pollution. In potato, this is a special problem due cultivation on light soils, irrigation and the shallow root system. Therefore, breeding of cultivars with improved nitrogen use efficiency and stable yields under reduced N fertilization is an important issue. Knowledge of genotype dependent adaptation to N-deficiency at the proteome level can help to understand regulation of N efficiency and development of N-efficient cultivars. Copyright © 2017 Elsevier B.V. All rights reserved.

Red blotch disease alters grape berry development and metabolism by interfering with the transcriptional and hormonal regulation of ripening

PubMed Central

Blanco-Ulate, Barbara; Hopfer, Helene; Figueroa-Balderas, Rosa; Ye, Zirou; Rivero, Rosa M.; Albacete, Alfonso; Pérez-Alfocea, Francisco; Koyama, Renata; Anderson, Michael M.; Smith, Rhonda J.; Ebeler, Susan E.

2017-01-01

Abstract Grapevine red blotch-associated virus (GRBaV) is a major threat to the wine industry in the USA. GRBaV infections (aka red blotch disease) compromise crop yield and berry chemical composition, affecting the flavor and aroma properties of must and wine. In this study, we combined genome-wide transcriptional profiling with targeted metabolite analyses and biochemical assays to characterize the impact of the disease on red-skinned berry ripening and metabolism. Using naturally infected berries collected from two vineyards, we were able to identify consistent berry responses to GRBaV across different environmental and cultural conditions. Specific alterations of both primary and secondary metabolism occurred in GRBaV-infected berries during ripening. Notably, GRBaV infections of post-véraison berries resulted in the induction of primary metabolic pathways normally associated with early berry development (e.g. thylakoid electron transfer and the Calvin cycle), while inhibiting ripening-associated pathways, such as a reduced metabolic flux in the central and peripheral phenylpropanoid pathways. We show that this metabolic reprogramming correlates with perturbations at multiple regulatory levels of berry development. Red blotch caused the abnormal expression of transcription factors (e.g. NACs, MYBs, and AP2-ERFs) and elements of the post-transcriptional machinery that function during red-skinned berry ripening. Abscisic acid, ethylene, and auxin pathways, which control both the initiation of ripening and stress responses, were also compromised. We conclude that GRBaV infections disrupt normal berry development and stress responses by altering transcription factors and hormone networks, which result in the inhibition of ripening pathways involved in the generation of color, flavor, and aroma compounds. PMID:28338755

Red blotch disease alters grape berry development and metabolism by interfering with the transcriptional and hormonal regulation of ripening.

PubMed

Blanco-Ulate, Barbara; Hopfer, Helene; Figueroa-Balderas, Rosa; Ye, Zirou; Rivero, Rosa M; Albacete, Alfonso; Pérez-Alfocea, Francisco; Koyama, Renata; Anderson, Michael M; Smith, Rhonda J; Ebeler, Susan E; Cantu, Dario

2017-02-01

Grapevine red blotch-associated virus (GRBaV) is a major threat to the wine industry in the USA. GRBaV infections (aka red blotch disease) compromise crop yield and berry chemical composition, affecting the flavor and aroma properties of must and wine. In this study, we combined genome-wide transcriptional profiling with targeted metabolite analyses and biochemical assays to characterize the impact of the disease on red-skinned berry ripening and metabolism. Using naturally infected berries collected from two vineyards, we were able to identify consistent berry responses to GRBaV across different environmental and cultural conditions. Specific alterations of both primary and secondary metabolism occurred in GRBaV-infected berries during ripening. Notably, GRBaV infections of post-véraison berries resulted in the induction of primary metabolic pathways normally associated with early berry development (e.g. thylakoid electron transfer and the Calvin cycle), while inhibiting ripening-associated pathways, such as a reduced metabolic flux in the central and peripheral phenylpropanoid pathways. We show that this metabolic reprogramming correlates with perturbations at multiple regulatory levels of berry development. Red blotch caused the abnormal expression of transcription factors (e.g. NACs, MYBs, and AP2-ERFs) and elements of the post-transcriptional machinery that function during red-skinned berry ripening. Abscisic acid, ethylene, and auxin pathways, which control both the initiation of ripening and stress responses, were also compromised. We conclude that GRBaV infections disrupt normal berry development and stress responses by altering transcription factors and hormone networks, which result in the inhibition of ripening pathways involved in the generation of color, flavor, and aroma compounds. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Characterization of ribulose-1, 5-bisphosphate carboxylase/oxygenase and transcriptional analysis of its related genes in Saccharina japonica (Laminariales, Phaeophyta)

NASA Astrophysics Data System (ADS)

Shao, Zhanru; Liu, Fuli; Li, Qiuying; Yao, Jianting; Duan, Delin

2014-03-01

Saccharina japonica is a common macroalga in sublittoral communities of cold seawater environments, and consequently may have highly efficient ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activity for carbon assimilation. In our study, we cloned the full-length Rubisco gene from S. japonica ( SJ-rbc). It contained an open reading frame for a large subunit gene ( SJ — rbcL) of 1 467 bp, a small subunit gene ( SJ-rbcS) of 420 bp, and a SJ-rbcL/S intergenic spacer of 269 bp. The deduced peptides of SJ-rbcL and SJ-rbcS were 488 and 139 amino acids with theoretical molecular weights and isoelectric points of 53.97 kDa, 5.81 and 15.84 kDa, 4.71, respectively. After induction with 1 mmol/L isopropyl- β-D-thiogalactopyranoside for 5 h and purification by Ni2+ affinity chromatography, electrophoresis and western blot detection demonstrated successful expression of the 55 kDa SJ-rbcL protein. Real-time quantitative PCR showed that the mRNA levels of SJ-rbcL in gametophytes increased when transferred into normal growth conditions and exhibited diurnal variations: increased expression during the day but suppressed expression at night. This observation implied that Rubisco played a role in normal gametophytic growth and development. In juvenile sporophytes, mRNA levels of SJ-rbcL, carbonic anhydrase, Calvin-Benson-Bassham cycle-related enzyme, and chloroplast light-harvesting protein were remarkably increased under continuous light irradiance. Similarly, expression of these genes was up-regulated under blue light irradiance at 350 μmol/(m2·s). Our results indicate that long-term white light and short-term blue light irradiance enhances juvenile sporophytic growth by synergistic effects of various photosynthetic elements.

RubisCO selection using the vigorously aerobic and metabolically versatile bacterium Ralstonia eutropha.

PubMed

Satagopan, Sriram; Tabita, F Robert

2016-08-01

Recapturing atmospheric CO2 is key to reducing global warming and increasing biological carbon availability. Ralstonia eutropha is a biotechnologically useful aerobic bacterium that uses the Calvin-Benson-Bassham (CBB) cycle and the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) for CO2 utilization, suggesting that it may be a useful host to bioselect RubisCO molecules with improved CO2 -capture capabilities. A host strain of R. eutropha was constructed for this purpose after deleting endogenous genes encoding two related RubisCOs. This strain could be complemented for CO2 -dependent growth by introducing native or heterologous RubisCO genes. Mutagenesis and suppressor selection identified amino acid substitutions in a hydrophobic region that specifically influences RubisCO's interaction with its substrates, particularly O2 , which competes with CO2 at the active site. Unlike most RubisCOs, the R. eutropha enzyme has evolved to retain optimal CO2 -fixation rates in a fast-growing host, despite the presence of high levels of competing O2 . Yet its structure-function properties resemble those of several commonly found RubisCOs, including the higher plant enzymes, allowing strategies to engineer analogous enzymes. Because R. eutropha can be cultured rapidly under harsh environmental conditions (e.g., with toxic industrial flue gas), in the presence of near saturation levels of oxygen, artificial selection and directed evolution studies in this organism could potentially impact efforts toward improving RubisCO-dependent biological CO2 utilization in aerobic environments. d-ribulose 1,5-bisphosphate carboxylase/oxygenase, EC 4.1.1.39; phosphoribulokinase, EC 2.7.1.19. © 2016 Federation of European Biochemical Societies.

NTRC-dependent redox balance of 2-Cys peroxiredoxins is needed for optimal function of the photosynthetic apparatus.

PubMed

Pérez-Ruiz, Juan Manuel; Naranjo, Belén; Ojeda, Valle; Guinea, Manuel; Cejudo, Francisco Javier

2017-11-07

Thiol-dependent redox regulation allows the rapid adaptation of chloroplast function to unpredictable changes in light intensity. Traditionally, it has been considered that chloroplast redox regulation relies on photosynthetically reduced ferredoxin (Fd), thioredoxins (Trxs), and an Fd-dependent Trx reductase (FTR), the Fd-FTR-Trxs system, which links redox regulation to light. More recently, a plastid-localized NADPH-dependent Trx reductase (NTR) with a joint Trx domain, termed NTRC, was identified. NTRC efficiently reduces 2-Cys peroxiredoxins (Prxs), thus having antioxidant function, but also participates in redox regulation of metabolic pathways previously established to be regulated by Trxs. Thus, the NTRC, 2-Cys Prxs, and Fd-FTR-Trxs redox systems may act concertedly, but the nature of the relationship between them is unknown. Here we show that decreased levels of 2-Cys Prxs suppress the phenotype of the Arabidopsis thaliana ntrc KO mutant. The excess of oxidized 2-Cys Prxs in NTRC-deficient plants drains reducing power from chloroplast Trxs, which results in low efficiency of light energy utilization and impaired redox regulation of Calvin-Benson cycle enzymes. Moreover, the dramatic phenotype of the ntrc-trxf1f2 triple mutant, lacking NTRC and f -type Trxs, was also suppressed by decreased 2-Cys Prxs contents, as the ntrc-trxf1f2-Δ2cp mutant partially recovered the efficiency of light energy utilization and exhibited WT rate of CO 2 fixation and growth phenotype. The suppressor phenotype was not caused by compensatory effects of additional chloroplast antioxidant systems. It is proposed that the Fd-FTR-Trx and NTRC redox systems are linked by the redox balance of 2-Cys Prxs, which is crucial for chloroplast function. Copyright © 2017 the Author(s). Published by PNAS.

Phosphoglycerate Kinases Are Co-Regulated to Adjust Metabolism and to Optimize Growth.

PubMed

Rosa-Téllez, Sara; Anoman, Armand Djoro; Flores-Tornero, María; Toujani, Walid; Alseek, Saleh; Fernie, Alisdair R; Nebauer, Sergio G; Muñoz-Bertomeu, Jesús; Segura, Juan; Ros, Roc

2018-02-01

In plants, phosphoglycerate kinase (PGK) converts 1,3-bisphosphoglycerate into 3-phosphoglycerate in glycolysis but also participates in the reverse reaction in gluconeogenesis and the Calvin-Benson cycle. In the databases, we found three genes that encode putative PGKs. Arabidopsis ( Arabidopsis thaliana ) PGK1 was localized exclusively in the chloroplasts of photosynthetic tissues, while PGK2 was expressed in the chloroplast/plastid of photosynthetic and nonphotosynthetic cells. PGK3 was expressed ubiquitously in the cytosol of all studied cell types. Measurements of carbohydrate content and photosynthetic activities in PGK mutants and silenced lines corroborated that PGK1 was the photosynthetic isoform, while PGK2 and PGK3 were the plastidial and cytosolic glycolytic isoforms, respectively. The pgk1.1 knockdown mutant displayed reduced growth, lower photosynthetic capacity, and starch content. The pgk3.2 knockout mutant was characterized by reduced growth but higher starch levels than the wild type. The pgk1.1 pgk3.2 double mutant was bigger than pgk3.2 and displayed an intermediate phenotype between the two single mutants in all measured biochemical and physiological parameters. Expression studies in PGK mutants showed that PGK1 and PGK3 were down-regulated in pgk3.2 and pgk1.1 , respectively. These results indicate that the down-regulation of photosynthetic activity could be a plant strategy when glycolysis is impaired to achieve metabolic adjustment and optimize growth. The double mutants of PGK3 and the triose-phosphate transporter ( pgk3.2 tpt3) displayed a drastic growth phenotype, but they were viable. This implies that other enzymes or nonspecific chloroplast transporters could provide 3-phosphoglycerate to the cytosol. Our results highlight both the complexity and the plasticity of the plant primary metabolic network. © 2018 American Society of Plant Biologists. All Rights Reserved.

Synthetic CO2-fixation enzyme cascades immobilized on self-assembled nanostructures that enhance CO2/O2 selectivity of RubisCO.

PubMed

Satagopan, Sriram; Sun, Yuan; Parquette, Jon R; Tabita, F Robert

2017-01-01

With increasing concerns over global warming and depletion of fossil-fuel reserves, it is attractive to develop innovative strategies to assimilate CO 2 , a greenhouse gas, into usable organic carbon. Cell-free systems can be designed to operate as catalytic platforms with enzymes that offer exceptional selectivity and efficiency, without the need to support ancillary reactions of metabolic pathways operating in intact cells. Such systems are yet to be exploited for applications involving CO 2 utilization and subsequent conversion to valuable products, including biofuels. The Calvin-Benson-Bassham (CBB) cycle and the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) play a pivotal role in global CO 2 fixation. We hereby demonstrate the co-assembly of two RubisCO-associated multienzyme cascades with self-assembled synthetic amphiphilic peptide nanostructures. The immobilized enzyme cascades sequentially convert either ribose-5-phosphate (R-5-P) or glucose, a simpler substrate, to ribulose 1,5-bisphosphate (RuBP), the acceptor for incoming CO 2 in the carboxylation reaction catalyzed by RubisCO. Protection from proteolytic degradation was observed in nanostructures associated with the small dimeric form of RubisCO and ancillary enzymes. Furthermore, nanostructures associated with a larger variant of RubisCO resulted in a significant enhancement of the enzyme's selectivity towards CO 2 , without adversely affecting the catalytic activity. The ability to assemble a cascade of enzymes for CO 2 capture using self-assembling nanostructure scaffolds with functional enhancements show promise for potentially engineering entire pathways (with RubisCO or other CO 2 -fixing enzymes) to redirect carbon from industrial effluents into useful bioproducts.

Comparative Transcriptomic Approaches Exploring Contamination Stress Tolerance in Salix sp. Reveal the Importance for a Metaorganismal de Novo Assembly Approach for Nonmodel Plants1[OPEN

PubMed Central

Brereton, Nicholas J. B.; Marleau, Julie; Nissim, Werther Guidi; Labrecque, Michel; Joly, Simon; Pitre, Frederic E.

2016-01-01

Metatranscriptomic study of nonmodel organisms requires strategies that retain the highly resolved genetic information generated from model organisms while allowing for identification of the unexpected. A real-world biological application of phytoremediation, the field growth of 10 Salix cultivars on polluted soils, was used as an exemplar nonmodel and multifaceted crop response well-disposed to the study of gene expression. Sequence reads were assembled de novo to create 10 independent transcriptomes, a global transcriptome, and were mapped against the Salix purpurea 94006 reference genome. Annotation of assembled contigs was performed without a priori assumption of the originating organism. Global transcriptome construction from 3.03 billion paired-end reads revealed 606,880 unique contigs annotated from 1588 species, often common in all 10 cultivars. Comparisons between transcriptomic and metatranscriptomic methodologies provide clear evidence that nonnative RNA can mistakenly map to reference genomes, especially to conserved regions of common housekeeping genes, such as actin, α/β-tubulin, and elongation factor 1-α. In Salix, Rubisco activase transcripts were down-regulated in contaminated trees across all 10 cultivars, whereas thiamine thizole synthase and CP12, a Calvin Cycle master regulator, were uniformly up-regulated. De novo assembly approaches, with unconstrained annotation, can improve data quality; care should be taken when exploring such plant genetics to reduce de facto data exclusion by mapping to a single reference genome alone. Salix gene expression patterns strongly suggest cultivar-wide alteration of specific photosynthetic apparatus and protection of the antenna complexes from oxidation damage in contaminated trees, providing an insight into common stress tolerance strategies in a real-world phytoremediation system. PMID:27002060

Regional Heritability Mapping Provides Insights into Dry Matter Content in African White and Yellow Cassava Populations.

PubMed

Okeke, Uche Godfrey; Akdemir, Deniz; Rabbi, Ismail; Kulakow, Peter; Jannink, Jean-Luc

2018-03-01

The HarvestPlus program for cassava ( Crantz) fortifies cassava with β-carotene by breeding for carotene-rich tubers (yellow cassava). However, a negative correlation between yellowness and dry matter (DM) content has been identified. We investigated the genetic control of DM in white and yellow cassava. We used regional heritability mapping (RHM) to associate DM with genomic segments in both subpopulations. Significant segments were subjected to candidate gene analysis and candidates were validated with prediction accuracies. The RHM procedure was validated via a simulation approach and revealed significant hits for white cassava on chromosomes 1, 4, 5, 10, 17, and 18, whereas hits for the yellow were on chromosome 1. Candidate gene analysis revealed genes in the carbohydrate biosynthesis pathway including plant serine-threonine protein kinases (SnRKs), UDP (uridine diphosphate)-glycosyltransferases, UDP-sugar transporters, invertases, pectinases, and regulons. Validation using 1252 unique identifiers from the SnRK gene family genome-wide recovered 50% of the predictive accuracy of whole-genome single nucleotide polymorphisms for DM, whereas validation using 53 likely genes (extracted from the literature) from significant segments recovered 32%. Genes including an acid invertase, a neutral or alkaline invertase, and a glucose-6-phosphate isomerase were validated on the basis of an a priori list for the cassava starch pathway, and also a fructose-biphosphate aldolase from the Calvin cycle pathway. The power of the RHM procedure was estimated as 47% when the causal quantitative trait loci generated 10% of the phenotypic variance (sample size = 451). Cassava DM genetics are complex and RHM may be useful for complex traits. Copyright © 2018 Crop Science Society of America.

GeoChip-based analysis of metabolic diversity of microbial communities at the Juan de Fuca Ridge hydrothermal vent

PubMed Central

Wang, Fengping; Zhou, Huaiyang; Meng, Jun; Peng, Xiaotong; Jiang, Lijing; Sun, Ping; Zhang, Chuanlun; Van Nostrand, Joy D.; Deng, Ye; He, Zhili; Wu, Liyou; Zhou, Jizhong; Xiao, Xiang

2009-01-01

Deep-sea hydrothermal vents are one of the most unique and fascinating ecosystems on Earth. Although phylogenetic diversity of vent communities has been extensively examined, their physiological diversity is poorly understood. In this study, a GeoChip-based, high-throughput metagenomics technology revealed dramatic differences in microbial metabolic functions in a newly grown protochimney (inner section, Proto-I; outer section, Proto-O) and the outer section of a mature chimney (4143-1) at the Juan de Fuca Ridge. Very limited numbers of functional genes were detected in Proto-I (113 genes), whereas much higher numbers of genes were detected in Proto-O (504 genes) and 4143-1 (5,414 genes). Microbial functional genes/populations in Proto-O and Proto-I were substantially different (around 1% common genes), suggesting a rapid change in the microbial community composition during the growth of the chimney. Previously retrieved cbbL and cbbM genes involved in the Calvin Benson Bassham (CBB) cycle from deep-sea hydrothermal vents were predominant in Proto-O and 4143-1, whereas photosynthetic green-like cbbL genes were the major components in Proto-I. In addition, genes involved in methanogenesis, aerobic and anaerobic methane oxidation (e.g., ANME1 and ANME2), nitrification, denitrification, sulfate reduction, degradation of complex carbon substrates, and metal resistance were also detected. Clone libraries supported the GeoChip results but were less effective than the microarray in delineating microbial populations of low biomass. Overall, these results suggest that the hydrothermal microbial communities are metabolically and physiologically highly diverse, and the communities appear to be undergoing rapid dynamic succession and adaptation in response to the steep temperature and chemical gradients across the chimney. PMID:19273854

Harvest index, a parameter conditioning responsiveness of wheat plants to elevated CO2

PubMed Central

Aranjuelo, Iker; Sanz-Sáez, Álvaro; Jauregui, Iván; Irigoyen, Juan J.; Araus, José L.; Sánchez-Díaz, Manuel; Erice, Gorka

2013-01-01

The expansion of the world’s population requires the development of high production agriculture. For this purpose, it is essential to identify target points conditioning crop responsiveness to predicted [CO2]. The aim of this study was to determine the relevance of ear sink strength in leaf protein and metabolomic profiles and its implications in photosynthetic activity and yield of durum wheat plants exposed to elevated [CO2]. For this purpose, a genotype with high harvest index (HI) (Triticum durum var. Sula) and another with low HI (Triticum durum var. Blanqueta) were exposed to elevated [CO2] (700 µmol mol–1 versus 400 µmol mol–1 CO2) in CO2 greenhouses. The obtained data highlighted that elevated [CO2] only increased plant growth in the genotype with the largest HI; Sula. Gas exchange analyses revealed that although exposure to 700 µmol mol–1 depleted Rubisco content, Sula was capable of increasing the light-saturated rate of CO2 assimilation (Asat) whereas, in Blanqueta, the carbohydrate imbalance induced the down-regulation of Asat. The specific depletion of Rubisco in both genotypes under elevated [CO2], together with the enhancement of other proteins in the Calvin cycle, revealed that there was a redistribution of N from Rubisco towards RuBP regeneration. Moreover, the down-regulation of N, NO3 –, amino acid, and organic acid content, together with the depletion of proteins involved in amino acid synthesis that was detected in Blanqueta grown at 700 µmol mol–1 CO2, revealed that inhibition of N assimilation was involved in the carbohydrate imbalance and consequently with the down-regulation of photosynthesis and growth in these plants. PMID:23564953

A Non-photosynthetic Diatom Reveals Early Steps of Reductive Evolution in Plastids.

PubMed

Kamikawa, Ryoma; Moog, Daniel; Zauner, Stefan; Tanifuji, Goro; Ishida, Ken-Ichiro; Miyashita, Hideaki; Mayama, Shigeki; Hashimoto, Tetsuo; Maier, Uwe G; Archibald, John M; Inagaki, Yuji

2017-09-01

Nonphotosynthetic plastids retain important biological functions and are indispensable for cell viability. However, the detailed processes underlying the loss of plastidal functions other than photosynthesis remain to be fully understood. In this study, we used transcriptomics, subcellular localization, and phylogenetic analyses to characterize the biochemical complexity of the nonphotosynthetic plastids of the apochlorotic diatom Nitzschia sp. NIES-3581. We found that these plastids have lost isopentenyl pyrophosphate biosynthesis and ribulose-1,5-bisphosphate carboxylase/oxygenase-based carbon fixation but have retained various proteins for other metabolic pathways, including amino acid biosynthesis, and a portion of the Calvin-Benson cycle comprised only of glycolysis/gluconeogenesis and the reductive pentose phosphate pathway (rPPP). While most genes for plastid proteins involved in these reactions appear to be phylogenetically related to plastid-targeted proteins found in photosynthetic relatives, we also identified a gene that most likely originated from a cytosolic protein gene. Based on organellar metabolic reconstructions of Nitzschia sp. NIES-3581 and the presence/absence of plastid sugar phosphate transporters, we propose that plastid proteins for glycolysis, gluconeogenesis, and rPPP are retained even after the loss of photosynthesis because they feed indispensable substrates to the amino acid biosynthesis pathways of the plastid. Given the correlated retention of the enzymes for plastid glycolysis, gluconeogenesis, and rPPP and those for plastid amino acid biosynthesis pathways in distantly related nonphotosynthetic plastids and cyanobacteria, we suggest that this substrate-level link with plastid amino acid biosynthesis is a key constraint against loss of the plastid glycolysis/gluconeogenesis and rPPP proteins in multiple independent lineages of nonphotosynthetic algae/plants. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

In search of the kingdom: the social gospel, settlement sociology, and the science of reform in America's progressive era.

PubMed

Williams, Joyce E; Maclean, Vicky M

2012-01-01

This critical narrative history examines the development of sociology in the United States during what has come to be labeled as the Progressive Era, roughly the years from the 1890s to World War I. Despite the label, this era was defined as much by social problems associated with industrialization, urbanization, and immigration as by the growth of its cities and the wealth of its capitalists. We explore the roots of American sociology in the transition of protestant theology from Calvinism to its reformation in the social gospel, the simultaneous development of settlement houses, and the "creation" of sociology as the science of reform. © 2012 Wiley Periodicals, Inc.

Eternal hate and conscience: on the filiation between Freudian psychoanalysis and sixteenth and early seventeenth century Protestant thought.

PubMed

Westerink, Herman

2011-01-01

In his seminar on ethics Jacques Lacan suggests there exists a "filiation or cultural paternity" between Freudian psychoanalysis and a "new direction of thought" that starts with Luther's conceptualization of God's eternal hate of man, and is then futher continued in Calvinism. In this article this thesis is explored. The author argues that there is not only a familiarity between the Protestant doctrines of predestination and Freud's reconstruction of prehistoric events and primal scenes, but also that Lacan's views on conscience formation and his elaborations of the complexity of moral decisions resembles Calvinist thought on civil and spiritual conscience, and the longing for restoration of a lost image of God.

KSC-03PD-2451

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. Daniel L. Tweed, with the Facilities Division, NASA Spaceport Services, addresses attendees at the ribbon cutting for the KSC Security gates. Tweed was project manager. The two new Security gates on Kennedy Parkway (Gate 2) and NASA Parkway (Gate 3) were activated Aug. 1, allowing the general public to have access to the new Space Commerce Way, which will provide access to the Research Park and KSC Visitor Complex, and providing an alternate route for the general public between Titusville and Merritt Island that is accessible 24 hours a day. The gates are staffed 24 hours daily. Others taking part in the ribbon cutting were Center Director Jim Kennedy; Chief, Protective & Safe Guards Office, Calvin L. Burch; SGS Deputy Program Manager William A. Sample; and Bobby Porter, with Oneida Construction.

Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salinero, Kennan Kellaris; Keller, Keith; Feil, William S.

2008-11-17

Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. The a priori prediction that the D. aromatica genome would contain previously characterized 'central' enzymes involved in anaerobic aromatic degradation proved to be false, suggesting the presence of novel anaerobic aromatic degradation pathways in this species. These missing pathways include the benzyl succinyl synthase (bssABC) genes (responsiblemore » for formate addition to toluene) and the central benzoylCoA pathway for monoaromatics. In depth analyses using existing TIGRfam, COG, and InterPro models, and the creation of de novo HMM models, indicate a highly complex lifestyle with a large number of environmental sensors and signaling pathways, including a relatively large number of GGDEF domain signal receptors and multiple quorum sensors. A number of proteins indicate interactions with an as yet unknown host, as indicated by the presence of predicted cell host remodeling enzymes, effector enzymes, hemolysin-like proteins, adhesins, NO reductase, and both type III and type VI secretory complexes. Evidence of biofilm formation including a proposed exopolysaccharide complex with the somewhat rare exosortase (epsH), is also present. Annotation described in this paper also reveals evidence for several metabolic pathways that have yet to be observed experimentally, including a sulphur oxidation (soxFCDYZAXB) gene cluster, Calvin cycle enzymes, and nitrogen fixation (including RubisCo, ribulose-phosphate 3-epimerase, and nif gene families, respectively). Analysis of the D. aromatica genome indicates there is much to be learned regarding the metabolic capabilities, and life-style, for this microbial species. Examples of recent gene duplication events in signaling as well as dioxygenase clusters are present, indicating selective gene family expansion as a relatively recent event in D. aromatica's evolutionary history. Gene families that constitute metabolic cycles presumed to create D. aromatica's environmental 'foot-print' indicate a high level of diversification between its predicted capabilities and those of its close relatives, A. aromaticum str EbN1 and Azoarcus BH72.« less

Investigating Hydroxyl at Asteroid 951 Gaspra

NASA Astrophysics Data System (ADS)

Granahan, James C.

2015-11-01

Recent investigations [Granahan, 2011; 2014] of Galileo Near Infrared Mapping Spectrometer (NIMS) observations of asteroid 951 Gaspra have detected an infrared absorption feature near 2.8 micrometers. These were detected in NIMS data acquired by the Galileo spacecraft on October 29, 1991 at wavelengths ranging from 0.7 - 5.2 micrometers [Carlson et al., 1992]. This abstract presents a summary of the investigation to identify the material creating the 2.8 micrometer spectral absorption feature. The current best match for the observed 951 Gaspra feature is the phyllosilicate bound hydroxyl signature present in a thermally desiccated QUE 99038 carbonaceous chondrite as measured by Takir et al. [2013].The 951 Gaspra absorption feature has been compared to a variety of hydroxyl bearing signatures. Many phyllosilicates, hydroxyl bearing minerals, have absorption minima at different positions (2.7 or 2.85 micrometers). It also differs from similar absorptions in a potential R chondrite analog, LAP 04840. The spectra LAP 04840 has a 2.7 micrometer feature due to biotite and a 2.9 micrometer feature due to adsorbed water [Klima et al., 2007]. 2.8 micrometer absorption minima have been found for adsorbed hydroxyl on the Moon [McCord et al., 2011] and various carbonaceous chondrites [Calvin and King, 1997; Takir et al., 2013]. The best match, with a minimum Euclidean distance difference to the 951 Gaspra feature, is found in the spectrum of QUE 99038 [Takir et al., 2013]. This spectrum is the product of an infrared measurement of a sample that had its adsorbed water baked off and removed in a vacuum chamber. The remaining hydroxyl in the sample belongs to a mixture of phyllosilicates dominated by the presence of cronstedtite.References: Calvin, W. M., and T. V. King (1997), Met. Planet. Sci., 32, 693-702. Carlson, R. W., et al. (1992), Bull. American Astro. Soc., 24, 932. Granahan, J. C. (2011), Icarus, 213, 265-272. Granahan, J. C. (2014), 45th LPSC, #1092. Klima, R., C. et al. (2007), 38th LPSC, #1710. McCord, T. B., et al. (2011), JGR, 116, E00G05. Takir, D., et al. (2013), Met. Planet. Sci., 48, 1618-1637.

Chemolithoautotrophy and its Relation to Magnetism and Biomineralization in Marine Magnetotactic Bacteria

NASA Astrophysics Data System (ADS)

Bazylinski, D. A.; Williams, T. J.; Zhang, C. L.; Scott, J. H.

2005-12-01

All cultured, marine, magnetite-producing, magnetotactic bacteria (MB) are capable of chemolithoautotrophy and use a number of electron donors to support this mode of growth including reduced sulfur compounds. Several vibrioid strains are known to rely on the Calvin-Benson-Bassham (CBB) cycle for autotrophy. An obligately microaerophilic, magnetite-producing, coccoid strain (MC-1) grew with sulfide and thiosulfate as electron donors and 14C-labelling experiments showed that virtually all cell C was derived from H14CO3-/14CO2 confirming autotrophy in this strain. Cell-free extracts of strain MC-1 did not exhibit ribulose-1,5-bisphosphate carboxylase-oxygenase (RubisCO) activity and nor were RubisCO genes found in the draft genome of the organism. Cell extracts also did not exhibit carbon monoxide dehydrogenase activity indicating that the acetyl-CoA pathway also does not function in strain MC-1. The 13C content of whole cells of strain MC-1 relative to the 13C content of the H14CO3-/14CO2 used for growth (Δδ13C) was -11.4 ppt. Cellular fatty acids showed enrichment of 13C relative to biomass. Activities for three key enzymes of the reverse or reductive tricarboxylic acid (rTCA) cycle were demonstrated for MC-1: fumarate reductase, pyruvate: acceptor oxidoreductase and 2-oxoglutarate: acceptor oxidoreductase. Although ATP citrate lyase (another key enzyme of the rTCA cycle) activity was not detected in cell-free extracts of strain MC-1 using commonly used assays for this enzyme, cell-free extract was found to rapidly cleave citrate, and the reaction was dependent upon the presence of ATP, coenzyme A and NADH. Thus, we infer the presence of an ATP-dependent citrate-cleaving enzyme or enzymes. The Δδ13C value and results from enzyme studies are consistent with the operation of the rTCA cycle for autotrophy in strain MC-1. Strain MC-1 appears to be the first known member of the alpha-Proteobacteria to assimilate CO2 during autotrophic growth using the rTCA cycle. Based on the type of chemolithoautotrophy described above, it is clear why marine magnetite-producing MB occupy a precise location, the oxic-anoxic interface, in vertical chemical gradients within chemically-stratified coastal environments: they must have an electron donor, sulfide and perhaps others, and an electron acceptor, O2. The presumed function of magnetosomes is that the magnetic dipole resulting from the magnetosomes aids the cell in locating and maintaining an optimal position within vertical chemical gradients. MB process large amounts of Fe in the biomineralization of magnetosomes: cells consist of 1-3% Fe (dry wt). Because of this, and the fact that many chemolithoautotrophic, non-magnetotactic bacteria occupy a similar niche, we have been investigating possible physiological reasons for the production of magnetosomes and the processing of such large amounts of Fe. We have found that some marine vibrioid strains grow in O2-gradient medium with Fe(II) as the electron donor. Cells appear to oxidize the Fe(II) and produce a layer of Fe oxyhydroxides within the gradient suggesting that cells obtain energy from the oxidation of Fe(II).

Rasmussen's legacy and the long arm of rational choice.

PubMed

Dekker, Sidney W A

2017-03-01

Rational choice theory says that operators and others make decisions by systematically and consciously weighing all possible outcomes along all relevant criteria. This paper first traces the long historical arm of rational choice thinking in the West to Judeo-Christian thinking, Calvin and Weber. It then presents a case study that illustrates the consequences of the ethic of rational choice and individual responsibility. It subsequently examines and contextualizes Rasmussen's legacy of pushing back against the long historical arm of rational choice, showing that bad outcomes are not the result of human immoral choice, but the product of normal interactions between people and systems. If we don't understand why people did what they did, Rasmussen suggested, it is not because people behaved inexplicably, but because we took the wrong perspective. Copyright © 2016 Elsevier Ltd. All rights reserved.

God: Do I have your attention?

PubMed

Colzato, Lorenza S; van Beest, Ilja; van den Wildenberg, Wery P M; Scorolli, Claudia; Dorchin, Shirley; Meiran, Nachshon; Borghi, Anna M; Hommel, Bernhard

2010-10-01

Religion is commonly defined as a set of rules, developed as part of a culture. Here we provide evidence that practice in following these rules systematically changes the way people attend to visual stimuli, as indicated by the individual sizes of the global precedence effect (better performance to global than to local features). We show that this effect is significantly reduced in Calvinism, a religion emphasizing individual responsibility, and increased in Catholicism and Judaism, religions emphasizing social solidarity. We also show that this effect is long-lasting (still affecting baptized atheists) and that its size systematically varies as a function of the amount and strictness of religious practices. These findings suggest that religious practice induces particular cognitive-control styles that induce chronic, directional biases in the control of visual attention. Copyright 2010 Elsevier B.V. All rights reserved.

Spectral distinctions between the leading and trailing hemispheres of Callisto - New observations

NASA Technical Reports Server (NTRS)

Calvin, Wendy M.; Clark, Roger N.

1993-01-01

Recent spectral observations of both the leading and trailing hemispheres of Callisto confirm the conclusions of Calvin and Clark (1991) that the water ice is typically large-grained, and the general spectral trend from 3 to 43 microns is caused by an adsorbed water band associated with hydrous minerals. On the leading hemisphere, a broad absorption near 3.4 microns was definitively identified and interpreted as being caused by fine-grained water ice. This band, coupled with the slope in the region from 2 to 2.5 microns, is indicative of a small amount, on the order of 1 to 2 percent, of fine-grained ice on the leading side. It is suggested that in the longer wavelength spectral region on the leading hemisphere an additional band correlated with NH4-bearing clays may be indicated.

Modeling the light-induced electric potential difference (ΔΨ), the pH difference (ΔpH) and the proton motive force across the thylakoid membrane in C3 leaves.

PubMed

Lyu, Hui; Lazár, Dušan

2017-01-21

A model was constructed which includes electron transport (linear and cyclic and Mehler type reaction) coupled to proton translocation, counter ion movement, ATP synthesis, and Calvin-Benson cycle. The focus is on modeling of the light-induced total electric potential difference (ΔΨ) which in this model originates from the bulk phase electric potential difference (ΔΨ b ), the localized electric potential difference (ΔΨ c ), as well as the surface electric potential difference (ΔΨ s ). The measured dual wavelength transmittance signal (ΔA515-560nm, electrochromic shift) was used as a proxy for experimental ΔΨ. The predictions for theoretical ΔΨ vary with assumed contribution of ΔΨ s , which might imply that the measured ΔA515-560nm trace on a long time scale reflects the interplay of the ΔΨ components. Simulations also show that partitioning of proton motive force (pmf) to ΔΨ b and ΔpH components is sensitive to the stoichiometric ratio of H + /ATP, energy barrier for ATP synthesis, ionic strength, buffer capacity and light intensity. Our model shows that high buffer capacity promotes the establishment of ΔΨ b , while the formation of pH i minimum is not 'dissipated' but 'postponed' until it reaches the same level as that for low buffer capacity. Under physiologically optimal conditions, the output of the model shows that at steady state in light, the ΔpH component is the main contributor to pmf to drive ATP synthesis while a low ΔΨ b persists energizing the membrane. Our model predicts 11mV as the resting electric potential difference across the thylakoid membrane in dark. We suggest that the model presented in this work can be integrated as a module into a more comprehensive model of oxygenic photosynthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rubisco mutagenesis provides new insight into limitations on photosynthesis and growth in Synechocystis PCC6803

PubMed Central

Marcus, Yehouda; Altman-Gueta, Hagit; Wolff, Yael; Gurevitz, Michael

2011-01-01

Orthophosphate (Pi) stimulates the activation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) while paradoxically inhibiting its catalysis. Of three Pi-binding sites, the roles of the 5P- and latch sites have been documented, whereas that of the 1P-site remained unclear. Conserved residues at the 1P-site of Rubisco from the cyanobacterium Synechocystis PCC6803 were substituted and the kinetic properties of the enzyme derivatives and effects on cell photosynthesis and growth were examined. While Pi-stimulated Rubisco activation diminished for enzyme mutants T65A/S and G404A, inhibition of catalysis by Pi remained unchanged. Together with previous studies, the results suggest that all three Pi-binding sites are involved in stimulation of Rubisco activation, whereas only the 5P-site is involved in inhibition of catalysis. While all the mutations reduced the catalytic turnover of Rubisco (Kcat) between 6- and 20-fold, the photosynthesis and growth rates under saturating irradiance and inorganic carbon (Ci) concentrations were only reduced 40–50% (in the T65A/S mutants) or not at all (G404A mutant). Analysis of the mutant cells revealed a 3-fold increase in Rubisco content that partially compensated for the reduced Kcat so that the carboxylation rate per chlorophyll was one-third of that in the wild type. Correlation between the kinetic properties of Rubisco and the photosynthetic rate (Pmax) under saturating irradiance and Ci concentrations indicate that a >60% reduction in Kcat can be tolerated before Pmax in Synechocystsis PCC6803 is affected. These results indicate that the limitation of Rubisco activity on the rate of photosynthesis in Synechocystis is low. Determination of Calvin cycle metabolites revealed that unlike in higher plants, cyanobacterial photosynthesis is constrained by phosphoglycerate reduction probably due to limitation of ATP or NADPH. PMID:21551078

Relationships between the Efficiencies of Photosystems I and II and Stromal Redox State in CO(2)-Free Air : Evidence for Cyclic Electron Flow in Vivo.

PubMed

Harbinson, J; Foyer, C H

1991-09-01

The responses of the efficiencies of photosystems I and II, stromal redox state (as indicated by NADP-malate dehydrogenase activation state), and activation of the Benson-Calvin cycle enzymes ribulose 1,5-bisphosphate carboxylase and fructose 1,6-bisphosphatase to varying irradiance were measured in pea (Pisum sativum L.) leaves operating close to the CO(2) compensation point. A comparison of the relationships among these parameters obtained from leaves in air was made with those obtained when the leaves were maintained in air from which the CO(2) had been removed. P700 was more oxidized at any measured irradiance in CO(2)-free air than in air. The relationship between the quantum efficiencies of the photosystems in CO(2)-free air was distinctly curvilinear in contrast to the predominantly linear relationship obtained with leaves in air. This nonlinearity may be consistent with the operation of cyclic electron flow around photosystem I because the quantum efficiency of photosystem II was much more restricted than the quantum efficiency of photosystem I. In CO(2)-free air, measured NADP-malate dehydrogenase activities varied considerably at low irradiances. However, at high irradiance the activity of the enzyme was low, implying that the stroma was oxidized. In contrast, fructose-1,6-bisphosphatase activities tended to increase with increasing electron flux through the photosystems. Ribulose-1,5-bisphosphate carboxylase activity remained relatively constant with respect to irradiance in CO(2)-free air, with an activation state 50% of maximum. We conclude that, at the CO(2) compensation point and high irradiance, low redox states are favored and that cyclic electron flow may be substantial. These two features may be the requirements necessary to trigger and maintain the dissipative processes in the thylakoid membrane.

Disruption of both chloroplastic and cytosolic FBPase genes results in a dwarf phenotype and important starch and metabolite changes in Arabidopsis thaliana.

PubMed

Rojas-González, José A; Soto-Súarez, Mauricio; García-Díaz, Ángel; Romero-Puertas, María C; Sandalio, Luisa M; Mérida, Ángel; Thormählen, Ina; Geigenberger, Peter; Serrato, Antonio J; Sahrawy, Mariam

2015-05-01

In this study, evidence is provided for the role of fructose-1,6-bisphosphatases (FBPases) in plant development and carbohydrate synthesis and distribution by analysing two Arabidopsis thaliana T-DNA knockout mutant lines, cyfbp and cfbp1, and one double mutant cyfbp cfbp1 which affect each FBPase isoform, cytosolic and chloroplastic, respectively. cyFBP is involved in sucrose synthesis, whilst cFBP1 is a key enzyme in the Calvin-Benson cycle. In addition to the smaller rosette size and lower rate of photosynthesis, the lack of cFBP1 in the mutants cfbp1 and cyfbp cfbp1 leads to a lower content of soluble sugars, less starch accumulation, and a greater superoxide dismutase (SOD) activity. The mutants also had some developmental alterations, including stomatal opening defects and increased numbers of root vascular layers. Complementation also confirmed that the mutant phenotypes were caused by disruption of the cFBP1 gene. cyfbp mutant plants without cyFBP showed a higher starch content in the chloroplasts, but this did not greatly affect the phenotype. Notably, the sucrose content in cyfbp was close to that found in the wild type. The cyfbp cfbp1 double mutant displayed features of both parental lines but had the cfbp1 phenotype. All the mutants accumulated fructose-1,6-bisphosphate and triose-phosphate during the light period. These results prove that while the lack of cFBP1 induces important changes in a wide range of metabolites such as amino acids, sugars, and organic acids, the lack of cyFBP activity in Arabidopsis essentially provokes a carbon metabolism imbalance which does not compromise the viability of the double mutant cyfbp cfbp1. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Proteome Analysis Reveals Extensive Light Stress-Response Reprogramming in the Seagrass Zostera muelleri (Alismatales, Zosteraceae) Metabolism

PubMed Central

Kumar, Manoj; Padula, Matthew P.; Davey, Peter; Pernice, Mathieu; Jiang, Zhijian; Sablok, Gaurav; Contreras-Porcia, Loretto; Ralph, Peter J.

2017-01-01

Seagrasses are marine ecosystem engineers that are currently declining in abundance at an alarming rate due to both natural and anthropogenic disturbances in ecological niches. Despite reports on the morphological and physiological adaptations of seagrasses to extreme environments, little is known of the molecular mechanisms underlying photo-acclimation, and/or tolerance in these marine plants. This study applies the two-dimensional isoelectric focusing (2D-IEF) proteomics approach to identify photo-acclimation/tolerance proteins in the marine seagrass Zostera muelleri. For this, Z. muelleri was exposed for 10 days in laboratory mesocosms to saturating (control, 200 μmol photons m−2 s−1), super-saturating (SSL, 600 μmol photons m−2 s−1), and limited light (LL, 20 μmol photons m−2 s−1) irradiance conditions. Using LC-MS/MS analysis, 93 and 40 protein spots were differentially regulated under SSL and LL conditions, respectively, when compared to the control. In contrast to the LL condition, Z. muelleri robustly tolerated super-saturation light than control conditions, evidenced by their higher relative maximum electron transport rate and minimum saturating irradiance values. Proteomic analyses revealed up-regulation and/or appearances of proteins belonging to the Calvin-Benson and Krebs cycle, glycolysis, the glycine cleavage system of photorespiration, and the antioxidant system. These proteins, together with those from the inter-connected glutamate-proline-GABA pathway, shaped Z. muelleri photosynthesis and growth under SSL conditions. In contrast, the LL condition negatively impacted the metabolic activities of Z. muelleri by down-regulating key metabolic enzymes for photosynthesis and the metabolism of carbohydrates and amino acids, which is consistent with the observation with lower photosynthetic performance under LL condition. This study provides novel insights into the underlying molecular photo-acclimation mechanisms in Z. muelleri, in addition to identifying protein-based biomarkers that could be used as early indicators to detect acute/chronic light stress in seagrasses to monitor seagrass health. PMID:28144245

Redox regulation of carbon storage and partitioning in response to light and sugars.

PubMed

Geigenberger, Peter; Kolbe, Anna; Tiessen, Axel

2005-06-01

Redox signals generated by the photosynthetic electron transport chain are known to be involved in regulating the Calvin cycle, ATP synthesis, and NADPH export from chloroplasts in response to light. The signal cascade involves transfer of electrons from photosystem I via the ferredoxin-thioredoxin system to target enzymes that are activated by reduction of regulatory disulphide bonds. The purpose of this review is to discuss recent findings showing that this concept can be extended to the regulation of carbon storage and partitioning in plants. Starch is the major carbon store in plants, and ADP-glucose pyrophosphorylase (AGPase) is the key regulatory enzyme of starch synthesis in the plastid. It has been shown that AGPase from potato tubers is subject to post-translational redox modification, and here experimental data will be provided showing that the isozyme from pea leaf chloroplasts is activated by reduced thioredoxin f or m in a similar way. Recent reports will be summarized providing in planta evidence that this mechanism regulates storage starch synthesis in response to light and sugars. Post-translational redox activation of AGPase in response to sugars is part of a signalling mechanism linking the rate of starch synthesis to the availability of carbon in diverse plant tissues. Some of the components of the signalling pathway reporting changes in the cytosolic sugar status to the plastid have been postulated, but detailed work is in progress to confirm the exact mode of action. Recent evidence will be discussed showing that key enzymes of de novo fatty acid synthesis (acetyl-CoA carboxylase) and ammonium assimilation (glutamine synthetase and glutamine:oxoglutarate amino transferase) are regulated by reversible disulphide-bond formation similar to AGPase. Redox regulation is proposed to be the preferred strategy of plastidial enzymes to regulate various metabolic processes such as carbon fixation, starch metabolism, lipid synthesis, and amino acid synthesis in response to physiological and environmental inputs.

A Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium

PubMed Central

Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J.

2014-01-01

The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free-living autotroph to parasitic heterotroph where host-independence has been unexpectedly preserved. PMID:24809511

Gene Expression Patterns during Light and Dark Infection of Prochlorococcus by Cyanophage

PubMed Central

Chisholm, Sallie W.

2016-01-01

Cyanophage infecting the marine cyanobacteria Prochlorococcus and Synechococcus require light and host photosystem activity for optimal reproduction. Many cyanophages encode multiple photosynthetic electron transport (PET) proteins, which are presumed to maintain electron flow and produce ATP and NADPH for nucleotide biosynthesis and phage genome replication. However, evidence suggests phage augment NADPH production via the pentose phosphate pathway (PPP), thus calling into question the need for NADPH production by PET. Genes implicated in cyclic PET have since been identified in cyanophage genomes. It remains an open question which mode of PET, cyclic or linear, predominates in infected cyanobacteria, and thus whether the balance is towards producing ATP or NADPH. We sequenced transcriptomes of a cyanophage (P-HM2) and its host (Prochlorococcus MED4) throughout infection in the light or in the dark, and analyzed these data in the context of phage replication and metabolite measurements. Infection was robust in the light, but phage were not produced in the dark. Host gene transcripts encoding high-light inducible proteins and two terminal oxidases (plastoquinol terminal oxidase and cytochrome c oxidase)—implicated in protecting the photosynthetic membrane from light stress—were the most enriched in light but not dark infection. Among the most diminished transcripts in both light and dark infection was ferredoxin–NADP+ reductase (FNR), which uses the electron acceptor NADP+ to generate NADPH in linear photosynthesis. The phage gene for CP12, which putatively inhibits the Calvin cycle enzyme that receives NADPH from FNR, was highly expressed in light infection. Therefore, both PET production of NADPH and its consumption by carbon fixation are putatively repressed during phage infection in light. Transcriptomic evidence is thus consistent with cyclic photophosphorylation using oxygen as the terminal electron acceptor as the dominant mode of PET under infection, with ATP from PET and NADPH from the PPP producing the energy and reducing equivalents for phage nucleotide biosynthesis and replication. PMID:27788196

A Novel Uncultured Bacterium of the Family Gallionellaceae: Description and Genome Reconstruction Based on the Metagenomic Analysis of Microbial Community in Acid Mine Drainage.

PubMed

Kadnikov, V V; Ivasenko, D A; Beletsky, A V; Mardanov, A V; Danilova, E V; Pimenov, N V; Karnachuk, O V; Ravin, N V

2016-07-01

Drainage waters at the metal mining areas often have low pH and high content of dissolved metals due to oxidation of sulfide minerals. Extreme conditions limit microbial diversity in- such ecosystems. A drainage water microbial community (6.5'C, pH 2.65) in an open pit at the Sherlovaya Gora polymetallic open-cast mine (Transbaikal region, Eastern Siberia, Russia) was studied using metagenomic techniques. Metagenome sequencing provided information for taxonomic and functional characterization of the micro- bial community. The majority of microorganisms belonged to a single uncultured lineage representing a new Betaproteobacteria species of the genus Gallionella. While no.acidophiles are known among the cultured members of the family Gallionellaceae, similar 16S rRNA gene sequences were detected in acid mine drain- ages. Bacteria ofthe genera Thiobacillus, Acidobacterium, Acidisphaera, and Acidithiobacillus,-which are com- mon in acid mine drainage environments, were the minor components of the community. Metagenomic data were -used to determine the almost complete (-3.4 Mb) composite genome of the new bacterial. lineage desig- nated Candidatus Gallionella acididurans ShG14-8. Genome analysis revealed that Fe(II) oxidation probably involved the cytochromes localized on the outer membrane of the cell. The electron transport chain included NADH dehydrogenase, a cytochrome bc1 complex, an alternative complex III, and cytochrome oxidases of the bd, cbb3, and bo3 types. Oxidation of reduced sulfur compounds probably involved the Sox system, sul- fide-quinone oxidoreductase, adenyl sulfate reductase, and sulfate adenyltransferase. The genes required for autotrophic carbon assimilation via the Calvin cycle were present, while no pathway for nitrogen fixation was revealed. High numbers of RND metal transporters and P type ATPases were probably responsible for resis- tance to heavy metals. The new microorganism was an aerobic chemolithoautotroph of the group of psychrotolerant iron- and sulfur-oxidizing acidophiles of the family Gallionellaceae, which are common in acid mine drainages.

Artificially evolved Synechococcus PCC6301 Rubisco variants exhibit improvements in folding and catalytic efficiency.

PubMed

Greene, Dina N; Whitney, Spencer M; Matsumura, Ichiro

2007-06-15

The photosynthetic CO2-fixing enzyme, Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), is responsible for most of the world's biomass, but is a slow non-specific catalyst. We seek to identify and overcome the chemical and biological constraints that limit the evolutionary potential of Rubisco in Nature. Recently, the horizontal transfer of Calvin cycle genes (rbcL, rbcS and prkA) from cyanobacteria (Synechococcus PCC6301) to gamma-proteobacteria (Escherichia coli) was emulated in the laboratory. Three unique Rubisco variants containing single (M259T) and double (M259T/A8S, M259T/F342S) amino acid substitutions in the L (large) subunit were identified after three rounds of random mutagenesis and selection in E. coli. Here we show that the M259T mutation did not increase steady-state levels of rbcL mRNA or L protein. It instead improved the yield of properly folded L subunit in E. coli 4-9-fold by decreasing its natural propensity to misfold in vivo and/or by enhancing its interaction with the GroES-GroEL chaperonins. The addition of osmolites to the growth media enhanced productive folding of the M259T L subunit relative to the wild-type L subunit, while overexpression of the trigger factor and DnaK/DnaJ/GrpE chaperones impeded Rubisco assembly. The evolved enzymes showed improvement in their kinetic properties with the M259T variant showing a 12% increase in carboxylation turnover rate (k(c)cat), a 15% improvement in its K(M) for CO2 and no change in its K(M) for ribulose-1,5-bisphosphate or its CO2/O2 selectivity. The results of the present study show that the directed evolution of the Synechococcus Rubisco in E. coli can elicit improvements in folding and catalytic efficiency.

Proteome Analysis Reveals Extensive Light Stress-Response Reprogramming in the Seagrass Zostera muelleri (Alismatales, Zosteraceae) Metabolism.

PubMed

Kumar, Manoj; Padula, Matthew P; Davey, Peter; Pernice, Mathieu; Jiang, Zhijian; Sablok, Gaurav; Contreras-Porcia, Loretto; Ralph, Peter J

2016-01-01

Seagrasses are marine ecosystem engineers that are currently declining in abundance at an alarming rate due to both natural and anthropogenic disturbances in ecological niches. Despite reports on the morphological and physiological adaptations of seagrasses to extreme environments, little is known of the molecular mechanisms underlying photo-acclimation, and/or tolerance in these marine plants. This study applies the two-dimensional isoelectric focusing (2D-IEF) proteomics approach to identify photo-acclimation/tolerance proteins in the marine seagrass Zostera muelleri . For this, Z. muelleri was exposed for 10 days in laboratory mesocosms to saturating (control, 200 μmol photons m -2 s -1 ), super-saturating (SSL, 600 μmol photons m -2 s -1 ), and limited light (LL, 20 μmol photons m -2 s -1 ) irradiance conditions. Using LC-MS/MS analysis, 93 and 40 protein spots were differentially regulated under SSL and LL conditions, respectively, when compared to the control. In contrast to the LL condition, Z. muelleri robustly tolerated super-saturation light than control conditions, evidenced by their higher relative maximum electron transport rate and minimum saturating irradiance values. Proteomic analyses revealed up-regulation and/or appearances of proteins belonging to the Calvin-Benson and Krebs cycle, glycolysis, the glycine cleavage system of photorespiration, and the antioxidant system. These proteins, together with those from the inter-connected glutamate-proline-GABA pathway, shaped Z. muelleri photosynthesis and growth under SSL conditions. In contrast, the LL condition negatively impacted the metabolic activities of Z. muelleri by down-regulating key metabolic enzymes for photosynthesis and the metabolism of carbohydrates and amino acids, which is consistent with the observation with lower photosynthetic performance under LL condition. This study provides novel insights into the underlying molecular photo-acclimation mechanisms in Z. muelleri , in addition to identifying protein-based biomarkers that could be used as early indicators to detect acute/chronic light stress in seagrasses to monitor seagrass health.

Metagenomic evidence for metabolism of trace atmospheric gases by high-elevation desert Actinobacteria

PubMed Central

Lynch, Ryan C.; Darcy, John L.; Kane, Nolan C.; Nemergut, Diana R.; Schmidt, Steve K.

2014-01-01

Previous surveys of very dry Atacama Desert mineral soils have consistently revealed sparse communities of non-photosynthetic microbes. The functional nature of these microorganisms remains debatable given the harshness of the environment and low levels of biomass and diversity. The aim of this study was to gain an understanding of the phylogenetic community structure and metabolic potential of a low-diversity mineral soil metagenome that was collected from a high-elevation Atacama Desert volcano debris field. We pooled DNA extractions from over 15 g of volcanic material, and using whole genome shotgun sequencing, observed only 75–78 total 16S rRNA gene OTUs3%. The phylogenetic structure of this community is significantly under dispersed, with actinobacterial lineages making up 97.9–98.6% of the 16S rRNA genes, suggesting a high degree of environmental selection. Due to this low diversity and uneven community composition, we assembled and analyzed the metabolic pathways of the most abundant genome, a Pseudonocardia sp. (56–72% of total 16S genes). Our assembly and binning efforts yielded almost 4.9 Mb of Pseudonocardia sp. contigs, which accounts for an estimated 99.3% of its non-repetitive genomic content. This genome contains a limited array of carbohydrate catabolic pathways, but encodes for CO2 fixation via the Calvin cycle. The genome also encodes complete pathways for the catabolism of various trace gases (H2, CO and several organic C1 compounds) and the assimilation of ammonia and nitrate. We compared genomic content among related Pseudonocardia spp. and estimated rates of non-synonymous and synonymous nucleic acid substitutions between protein coding homologs. Collectively, these comparative analyses suggest that the community structure and various functional genes have undergone strong selection in the nutrient poor desert mineral soils and high-elevation atmospheric conditions. PMID:25566214

Transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration in Rhodobacter sphaeroides 2.4.1.

PubMed

Arai, Hiroyuki; Roh, Jung Hyeob; Kaplan, Samuel

2008-01-01

Rhodobacter sphaeroides 2.4.1 is a facultative photosynthetic anaerobe that grows by anoxygenic photosynthesis under anaerobic-light conditions. Changes in energy generation pathways under photosynthetic and aerobic respiratory conditions are primarily controlled by oxygen tensions. In this study, we performed time series microarray analyses to investigate transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration. Major changes in gene expression profiles occurred in the initial 15 min after the shift from anaerobic-light to aerobic-dark conditions, with changes continuing to occur up to 4 hours postshift. Those genes whose expression levels changed significantly during the time series were grouped into three major classes by clustering analysis. Class I contained genes, such as that for the aa3 cytochrome oxidase, whose expression levels increased after the shift. Class II contained genes, such as those for the photosynthetic apparatus and Calvin cycle enzymes, whose expression levels decreased after the shift. Class III contained genes whose expression levels temporarily increased during the time series. Many genes for metabolism and transport of carbohydrates or lipids were significantly induced early during the transition, suggesting that those endogenous compounds were initially utilized as carbon sources. Oxidation of those compounds might also be required for maintenance of redox homeostasis after exposure to oxygen. Genes for the repair of protein and sulfur groups and uptake of ferric iron were temporarily upregulated soon after the shift, suggesting they were involved in a response to oxidative stress. The flagellar-biosynthesis genes were expressed in a hierarchical manner at 15 to 60 min after the shift. Numerous transporters were induced at various time points, suggesting that the cellular composition went through significant changes during the transition from anaerobic photosynthesis to aerobic respiration. Analyses of these data make it clear that numerous regulatory activities come into play during the transition from one homeostatic state to another.

The return of metabolism: biochemistry and physiology of the pentose phosphate pathway

PubMed Central

Stincone, Anna; Prigione, Alessandro; Cramer, Thorsten; Wamelink, Mirjam M. C.; Campbell, Kate; Cheung, Eric; Olin-Sandoval, Viridiana; Grüning, Nana-Maria; Krüger, Antje; Alam, Mohammad Tauqeer; Keller, Markus A.; Breitenbach, Michael; Brindle, Kevin M.; Rabinowitz, Joshua D.; Ralser, Markus

2015-01-01

The pentose phosphate pathway (PPP) is a fundamental component of cellular metabolism. The PPP is important to maintain carbon homoeostasis, to provide precursors for nucleotide and amino acid biosynthesis, to provide reducing molecules for anabolism, and to defeat oxidative stress. The PPP shares reactions with the Entner–Doudoroff pathway and Calvin cycle and divides into an oxidative and non-oxidative branch. The oxidative branch is highly active in most eukaryotes and converts glucose 6-phosphate into carbon dioxide, ribulose 5-phosphate and NADPH. The latter function is critical to maintain redox balance under stress situations, when cells proliferate rapidly, in ageing, and for the ‘Warburg effect’ of cancer cells. The non-oxidative branch instead is virtually ubiquitous, and metabolizes the glycolytic intermediates fructose 6-phosphate and glyceraldehyde 3-phosphate as well as sedoheptulose sugars, yielding ribose 5-phosphate for the synthesis of nucleic acids and sugar phosphate precursors for the synthesis of amino acids. Whereas the oxidative PPP is considered unidirectional, the non-oxidative branch can supply glycolysis with intermediates derived from ribose 5-phosphate and vice versa, depending on the biochemical demand. These functions require dynamic regulation of the PPP pathway that is achieved through hierarchical interactions between transcriptome, proteome and metabolome. Consequently, the biochemistry and regulation of this pathway, while still unresolved in many cases, are archetypal for the dynamics of the metabolic network of the cell. In this comprehensive article we review seminal work that led to the discovery and description of the pathway that date back now for 80 years, and address recent results about genetic and metabolic mechanisms that regulate its activity. These biochemical principles are discussed in the context of PPP deficiencies causing metabolic disease and the role of this pathway in biotechnology, bacterial and parasite infections, neurons, stem cell potency and cancer metabolism. PMID:25243985

How Linus Pauling Finally Got the Priestley Medal of the American Chemical Society

NASA Astrophysics Data System (ADS)

Davenport, Derek A.

1998-10-01

Late in 1981 I started firming up plans for a symposium marking the 250th anniversary of the birth of Joseph Priestley in 1733. The symposium was scheduled for the 1983 Fall Meeting of the American Chemical Society to be held in Washington D. C. Because of Priestley's wide-ranging interests and activities, the speakers were to include not only chemists and historians but also a political scientist, a grammarian, and a Unitarian minister. The closing session was to open with Melvin Calvin speaking on "Artificial Photosynthesis"-a phenomenon Priestley was the first to observe, albeit somewhat confusedly. Next came Fred Basolo, then president of the American Chemical Society, on "Synthetic Oxygen Carriers of Biological Interest"-Priestley had abeen among the first to remark on the role of dephlogisticated air (oxygen) in the interconversion of venous and arterial blood.

KSC-2011-3331

NASA Image and Video Library

2011-05-05

CAPE CANAVERAL, Fla. -- During a celebration at Complex 5/6 on Cape Canaveral Air Force Station in Florida, Mercury astronaut Scott Carpenter greets Calvin Fowler, the launch conductor for Carpenter's Mercury-Atlas 7 mission on May 24, 1962. The celebration was held at the launch site of the first U.S. manned spaceflight May 5, 1961, to mark the 50th anniversary of the flight. Fifty years ago, astronaut Alan Shepard lifted off inside the Mercury capsule, "Freedom 7," atop an 82-foot-tall Mercury-Redstone rocket at 9:34 a.m. EST, sending him on a remarkably successful, 15-minute suborbital flight. The event was attended by more than 200 workers from the original Mercury program and included a re-creation of Shepard's flight and recovery, as well as a tribute to his contributions as a moonwalker on the Apollo 14 lunar mission. For more information, visit www.nasa.gov/topics/history/milestones/index.html. Photo credit: NASA/Kim Shiflett

PhamDB: a web-based application for building Phamerator databases.

PubMed

Lamine, James G; DeJong, Randall J; Nelesen, Serita M

2016-07-01

PhamDB is a web application which creates databases of bacteriophage genes, grouped by gene similarity. It is backwards compatible with the existing Phamerator desktop software while providing an improved database creation workflow. Key features include a graphical user interface, validation of uploaded GenBank files, and abilities to import phages from existing databases, modify existing databases and queue multiple jobs. Source code and installation instructions for Linux, Windows and Mac OSX are freely available at https://github.com/jglamine/phage PhamDB is also distributed as a docker image which can be managed via Kitematic. This docker image contains the application and all third party software dependencies as a pre-configured system, and is freely available via the installation instructions provided. snelesen@calvin.edu. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Impact relevance and usability of high resolution climate modeling and data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arnott, James C.

2016-10-30

The Aspen Global Change Institute hosted a technical science workshop entitled, “Impact Relevance and Usability of High-Resolution Climate Modeling and Datasets,” on August 2-7, 2015 in Aspen, CO. Kate Calvin (Pacific Northwest National Laboratory), Andrew Jones (Lawrence Berkeley National Laboratory) and Jean-François Lamarque (NCAR) served as co-chairs for the workshop. The meeting included the participation of 29 scientists for a total of 145 participant days. Following the workshop, workshop co-chairs authored a meeting report published in Eos on April 27, 2016. Insights from the workshop directly contributed to the formation of a new DOE-supported project co-led by workshop co-chair Andymore » Jones. A subset of meeting participants continue to work on a publication on institutional innovations that can support the usability of high resolution modeling, among other sources of climate information.« less

Computer modeling of electron and proton transport in chloroplasts.

PubMed

Tikhonov, Alexander N; Vershubskii, Alexey V

2014-07-01

Photosynthesis is one of the most important biological processes in biosphere, which provides production of organic substances from atmospheric CO2 and water at expense of solar energy. In this review, we contemplate computer models of oxygenic photosynthesis in the context of feedback regulation of photosynthetic electron transport in chloroplasts, the energy-transducing organelles of the plant cell. We start with a brief overview of electron and proton transport processes in chloroplasts coupled to ATP synthesis and consider basic regulatory mechanisms of oxygenic photosynthesis. General approaches to computer simulation of photosynthetic processes are considered, including the random walk models of plastoquinone diffusion in thylakoid membranes and deterministic approach to modeling electron transport in chloroplasts based on the mass action law. Then we focus on a kinetic model of oxygenic photosynthesis that includes key stages of the linear electron transport, alternative pathways of electron transfer around photosystem I (PSI), transmembrane proton transport and ATP synthesis in chloroplasts. This model includes different regulatory processes: pH-dependent control of the intersystem electron transport, down-regulation of photosystem II (PSII) activity (non-photochemical quenching), the light-induced activation of the Bassham-Benson-Calvin (BBC) cycle. The model correctly describes pH-dependent feedback control of electron transport in chloroplasts and adequately reproduces a variety of experimental data on induction events observed under different experimental conditions in intact chloroplasts (variations of CO2 and O2 concentrations in atmosphere), including a complex kinetics of P700 (primary electron donor in PSI) photooxidation, CO2 consumption in the BBC cycle, and photorespiration. Finally, we describe diffusion-controlled photosynthetic processes in chloroplasts within the framework of the model that takes into account complex architecture of chloroplasts and lateral heterogeneity of lamellar system of thylakoids. The lateral profiles of pH in the thylakoid lumen and in the narrow gap between grana thylakoids have been calculated under different metabolic conditions. Analyzing topological aspects of diffusion-controlled stages of electron and proton transport in chloroplasts, we conclude that along with the NPQ mechanism of attenuation of PSII activity and deceleration of PQH2 oxidation by the cytochrome b6f complex caused by the lumen acidification, the intersystem electron transport may be down-regulated due to the light-induced alkalization of the narrow partition between adjacent thylakoids of grana. The computer models of electron and proton transport described in this article may be integrated as appropriate modules into a comprehensive model of oxygenic photosynthesis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2014-07-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2009-12-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

From Calvin Klein to Paris Hilton and MySpace: adolescents, sex, and the media.

PubMed

Brown, Jane D; Strasburger, Victor C

2007-12-01

In the absence of effective sex education at home or school, the media have become important sources of sexual information for adolescents in the United States. Mainstream media inundate teenagers with sexual images and innuendoes. In the most recent content analysis of American primetime TV, more than three-fourths of the shows had sexual content; yet less than 15% contained any references to responsible sexuality, abstinence, the risk of pregnancy, or the risk of sexually transmitted infections. Dozens of studies attest to the power of the media to influence teenagers' beliefs and attitudes about sex. Three longitudinal studies have all found that adolescents exposed to more sexual content are more likely to begin having sexual intercourse earlier than their peers who see or hear less about sex in the media. The media could become part of the solution as well as part of the problem - if there were more responsible portrayals of human sex and more widespread advertising of birth control products.

Psychopharmacological enhancement: a conceptual framework

PubMed Central

2012-01-01

The availability of a range of new psychotropic agents raises the possibility that these will be used for enhancement purposes (smart pills, happy pills, and pep pills). The enhancement debate soon raises questions in philosophy of medicine and psychiatry (eg, what is a disorder?), and this debate in turn raises fundament questions in philosophy of language, science, and ethics. In this paper, a naturalistic conceptual framework is proposed for addressing these issues. This framework begins by contrasting classical and critical concepts of categories, and then puts forward an integrative position that is based on cognitive-affective research. This position can in turn be used to consider the debate between pharmacological Calvinism (which may adopt a moral metaphor of disorder) and psychotropic utopianism (which may emphasize a medical metaphor of disorder). I argue that psychiatric treatment of serious psychiatric disorders is justified, and that psychotropics are an acceptable kind of intervention. The use of psychotropics for sub-threshold phenomena requires a judicious weighing of the relevant facts (which are often sparse) and values. PMID:22244084

Directions for Optimization of Photosynthetic Carbon Fixation: RuBisCO's Efficiency May Not Be So Constrained After All.

PubMed

Cummins, Peter L; Kannappan, Babu; Gready, Jill E

2018-01-01

The ubiquitous enzyme Ribulose 1,5-bisphosphate carboxylase-oxygenase (RuBisCO) fixes atmospheric carbon dioxide within the Calvin-Benson cycle that is utilized by most photosynthetic organisms. Despite this central role, RuBisCO's efficiency surprisingly struggles, with both a very slow turnover rate to products and also impaired substrate specificity, features that have long been an enigma as it would be assumed that its efficiency was under strong evolutionary pressure. RuBisCO's substrate specificity is compromised as it catalyzes a side-fixation reaction with atmospheric oxygen; empirical kinetic results show a trend to tradeoff between relative specificity and low catalytic turnover rate. Although the dominant hypothesis has been that the active-site chemistry constrains the enzyme's evolution, a more recent study on RuBisCO stability and adaptability has implicated competing selection pressures. Elucidating these constraints is crucial for directing future research on improving photosynthesis, as the current literature casts doubt on the potential effectiveness of site-directed mutagenesis to improve RuBisCO's efficiency. Here we use regression analysis to quantify the relationships between kinetic parameters obtained from empirical data sets spanning a wide evolutionary range of RuBisCOs. Most significantly we found that the rate constant for dissociation of CO 2 from the enzyme complex was much higher than previous estimates and comparable with the corresponding catalytic rate constant. Observed trends between relative specificity and turnover rate can be expressed as the product of negative and positive correlation factors. This provides an explanation in simple kinetic terms of both the natural variation of relative specificity as well as that obtained by reported site-directed mutagenesis results. We demonstrate that the kinetic behaviour shows a lesser rather than more constrained RuBisCO, consistent with growing empirical evidence of higher variability in relative specificity. In summary our analysis supports an explanation for the origin of the tradeoff between specificity and turnover as due to competition between protein stability and activity, rather than constraints between rate constants imposed by the underlying chemistry. Our analysis suggests that simultaneous improvement in both specificity and turnover rate of RuBisCO is possible.

Large-scale protein analysis of European beech trees following four vegetation periods of twice ambient ozone exposure.

PubMed

Kerner, René; Delgado-Eckert, Edgar; Ernst, Dieter; Dupuy, Jean-William; Grams, Thorsten E E; Barbro Winkler, J; Lindermayr, Christian; Müller-Starck, Gerhard

2014-09-23

In the present study, we performed a large-scale protein analysis based on 2-DE DIGE to examine the effects of ozone on the leaves of juvenile European beech (Fagus sylvatica L.), one of the most important deciduous tree species in Central Europe. To this end, beech trees were grown under field conditions and subjected to ambient and twice ambient ozone concentrations during the vegetation periods of four consecutive years. The twice ambient ozone concentration altered the abundance of 237 protein spots, which showed relative ratios higher than 30% compared to the ambient control trees. A total of 74 protein spots were subjected to mass spectrometry identification (LC-MS/MS), followed by homology-driven searches. The differentially expressed proteins participate in key biological processes including the Calvin cycle and photosynthesis, carbon metabolism, defense- and stress-related responses, detoxification mechanisms, protein folding and degradation, and mechanisms involved in senescence. The ozone-induced responses provide evidence of a changing carbon metabolism and counteraction against increased levels of reactive oxygen species. This study provides useful information on how European beech, an economically and ecologically important tree species, reacts on the molecular level to increased ozone concentrations expected in the near future. The main emphasis in the present study was placed on identifying differentially abundant proteins after long-term ozone exposure under climatically realistic settings, rather than short-term responses or reactions under laboratory conditions. Additionally, using nursery-grown beech trees, we took into account the natural genotypic variation of this species. As such, the results presented here provide information on molecular responses to ozone in an experimental plant system at very close to natural conditions. Furthermore, this proteomic approach was supported by previous studies on the present experiment. Ultimately, the combination of this proteomic approach with several approaches including transcriptomics, analysis of non-structural carbohydrates, and morphological effects contributes to a more global picture of how beech trees react under increased ozone concentrations. Copyright © 2014. Published by Elsevier B.V.

Drought stress and carbon assimilation in a warming climate: Reversible and irreversible impacts.

PubMed

Feller, Urs

2016-09-20

Global change is characterized by increased CO 2 concentration in the atmosphere, increasing average temperature and more frequent extreme events including drought periods, heat waves and flooding. Especially the impacts of drought and of elevated temperature on carbon assimilation are considered in this review. Effects of extreme events on the subcellular level as well as on the whole plant level may be reversible, partially reversible or irreversible. The photosynthetically active biomass depends on the number and the size of mature leaves and the photosynthetic activity in this biomass during stress and subsequent recovery phases. The total area of active leaves is determined by leaf expansion and senescence, while net photosynthesis per leaf area is primarily influenced by stomatal opening (stomatal conductance), mesophyll conductance, activity of the photosynthetic apparatus (light absorption and electron transport, activity of the Calvin cycle) and CO 2 release by decarboxylation reactions (photorespiration, dark respiration). Water status, stomatal opening and leaf temperature represent a "magic triangle" of three strongly interacting parameters. The response of stomata to altered environmental conditions is important for stomatal limitations. Rubisco protein is quite thermotolerant, but the enzyme becomes at elevated temperature more rapidly inactivated (decarbamylation, reversible effect) and must be reactivated by Rubisco activase (carbamylation of a lysine residue). Rubisco activase is present under two forms (encoded by separate genes or products of alternative splicing of the pre-mRNA from one gene) and is very thermosensitive. Rubisco activase was identified as a key protein for photosynthesis at elevated temperature (non-stomatal limitation). During a moderate heat stress Rubisco activase is reversibly inactivated, but during a more severe stress (higher temperature and/or longer exposure) the protein is irreversibly inactivated, insolubilized and finally degraded. On the level of the leaf, this loss of photosynthetic activity may still be reversible when new Rubisco activase is produced by protein synthesis. Rubisco activase as well as enzymes involved in the detoxification of reactive oxygen species or in osmoregulation are considered as important targets for breeding crop plants which are still productive under drought and/or at elevated leaf temperature in a changing climate. Copyright © 2016 Elsevier GmbH. All rights reserved.

Metabolic Environments and Genomic Features Associated with Pathogenic and Mutualistic Interactions between Bacteria and Plants is accepted for publication in MPMI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karpinets, Tatiana V; Park, Byung H; Syed, Mustafa H

Most bacterial symbionts of plants are phenotypically characterized by their parasitic or matualistic relationship with the host; however, the genomic characteristics that likely discriminate mutualistic symbionts from pathogens of plants are poorly understood. This study comparatively analyzed the genomes of 54 plant-symbiontic bacteria, 27 mutualists and 27 pathogens, to discover genomic determinants of their parasitic and mutualistic nature in terms of protein family domains, KEGG orthologous groups, metabolic pathways and families of carbohydrate-active enzymes (CAZymes). We further used all bacteria with sequenced genomesl, published microarrays and transcriptomics experimental datasets, and literature to validate and to explore results of the comparison.more » The analysis revealed that genomes of mutualists are larger in size and higher in GC content and encode greater molecular, functional and metabolic diversity than the investigated genomes of pathogens. This enriched molecular and functional enzyme diversity included constructive biosynthetic signatures of CAZymes and metabolic pathways in genomes of mutualists compared with catabolic signatures dominant in the genomes of pathogens. Another discriminative characteristic of mutualists is the co-occurence of gene clusters required for the expression and function of nitrogenase and RuBisCO. Analysis of previously published experimental data indicate that nitrogen-fixing mutualists may employ Rubisco to fix CO2 not in the canonical Calvin-Benson-Basham cycle but in a novel metabolic pathway, here called Rubisco-based glycolysis , to increase efficiency of sugar utilization during the symbiosis with plants. An important discriminative characteristic of plant pathogenic bacteria is two groups of genes likely encoding effector proteins involved in host invasion and a genomic locus encoding a putative secretion system that includes a DUF1525 domain protein conserved in pathogens of plants and of other organisms. The protein belongs to the same clan of thioredoxins as the circadian clock protein kaiB found in many mutualistic symbionts and highly abundant in blood cells colonized by a human pathogen, Salmonella enterica serotype Typhi, the cause of typhoid fever.« less

High-Affinity Methanotrophy Informed by Genome-Wide Analysis of Upland Soil Cluster Alpha (USCα) from Axel Heiberg Island, Canadian High Arctic

NASA Astrophysics Data System (ADS)

Rusley, C.; Onstott, T. C.; Lau, M.

2017-12-01

Methane (CH4) is a potent greenhouse gas whose proper budgeting is vital to climate predictions. Recent studies have identified upland Arctic mineral cryosols as consistent CH4 sinks, drawing CH4 from both the atmosphere and underlying anaerobic soil layers. Global atmospheric CH4 uptake is proposed to be mediated by high-affinity methanotrophs based on the detection of the marker gene pmoA (particulate methane monooxygenase beta subunit). However, a lack of pure cultures and scarcity of genomic information have hindered our understanding of their metabolic capabilities and versatility. Together with the missing genetic linkage between its pmoA and 16S ribosomal RNA (rRNA) gene, the factors that control the distribution and magnitude of high-affinity methanotrophy in the Arctic permafrost-affected region have remained elusive. Using 21 metagenomic datasets of surface soils obtained from long-term core incubation experiments,1 this bioinformatics study aimed to reconstruct the draft genome of the Upland Soil Cluster α-proteobacteria (USCα), the high-affinity methanotroph previously detected in the samples,2 and to determine its phylogeny and metabolic requirements. We obtained a genome bin containing the high-affinity form of the USCα-like pmoA gene. The 3.03 Mbp assembly is 91.6% complete with a unique set of single-copy marker genes. The 16S rRNA gene fragment of USCα belongs to the α-proteobacterial family Beijerinckiaceae. Genome annotation indicates possible formaldehyde oxidation via tetrahydromethanopterin-linked C1 transfer pathways, acetate utilization, carbon fixation via the Calvin-Benson-Bassham cycle, and glycogen production. Notably, the key enzymes for formaldehyde assimilation via the serine and ribulose monophosphate pathways are missing. The presence of genes encoding nitrate reductase and hemoglobin suggests adaptation to low O2 under water-logged conditions. Since USCα has versatile carbon metabolisms, it may not be an obligate methanotroph. Stackhouse, B. T. et al. J. Geophys. Res. Biogeosciences 120, 1764-1784 (2015). Lau, M. C. Y. et al. ISME J. 9, 1880-1891 (2015).

The AAPT Advanced Laboratory Task Force Report

NASA Astrophysics Data System (ADS)

Dunham, Jeffrey

2008-04-01

In late 2005, the American Association of Physics Teachers (AAPT) assembled a seven-member Advanced Laboratory Task Force^ to recommend ways that AAPT could increase the degree and effectiveness of its interactions with physics teachers of upper-division physics laboratories, with the ultimate goal of improving the teaching of advanced laboratories. The task force completed its work during the first half of 2006 and its recommendations were presented to the AAPT Executive Committee in July 2006. This talk will present the recommendations of the task force and actions taken by AAPT in response to them. The curricular goals of the advanced laboratory course at various institutions will also be discussed. The talk will conclude with an appeal to the APS membership to support ongoing efforts to revitalize advanced laboratory course instruction. ^Members of the Advanced Laboratory Task Force: Van Bistrow, University of Chicago; Bob DeSerio, University of Florida; Jeff Dunham, Middlebury College (Chair); Elizabeth George, Wittenburg University; Daryl Preston, California State University, East Bay; Patricia Sparks, Harvey Mudd College; Gerald Taylor, James Madison University; and David Van Baak, Calvin College.

[Different NaCl-dependence of the circadian CO2-gas-exchange of some halophil growing coastal plants].

PubMed

Treichel, Siegfried; Bauer, Peter

1974-03-01

CO 2 -exchange, diurnal changes in malate- and ion concentrations of the halophytes Carpobrotus edulis, Crithmum maritimum, Mesembryanthemum nodiflorum, Salicornia fruticosa, Suaeda maritima, and Trifolium fragiferum were investigated after culture at different NaCl concentrations. In Carp. edulis and Mes. nodiflorum the diurnal rhythm of CO 2 -exchange is in accordance with that of crassulacean acid metabolism (CAM), in Sal. fruticosa, Crithm. maritimum, Suaeda maritima, and Trif. fragiferum with that of Benson-Calvin metabolism (C 3 ). Malate concentration and CO 2 uptake in the sap latter group are not influenced. On the other hand, Carp. edulis and Mes. nodiflorum show an accumulation of malate during the night, which can be interpreted as a further indication of CAM.The two species most resistant to NaCl, Carp. edulis and Sal. fruticosa, greatly differ very much in their NaCl content. NaCl concentration in Salicornia is four times higher than in Carpobrotus.The different metabolic properties studied might be of ecological importance for the plants in their natural habitats. The effect of NaCl on metabolic processes is discussed.

Genetic and nutrient modulation of acetyl-CoA levels in Synechocystis for n-butanol production.

PubMed

Anfelt, Josefine; Kaczmarzyk, Danuta; Shabestary, Kiyan; Renberg, Björn; Rockberg, Johan; Nielsen, Jens; Uhlén, Mathias; Hudson, Elton P

2015-10-16

There is a strong interest in using photosynthetic cyanobacteria as production hosts for biofuels and chemicals. Recent work has shown the benefit of pathway engineering, enzyme tolerance, and co-factor usage for improving yields of fermentation products. An n-butanol pathway was inserted into a Synechocystis mutant deficient in polyhydroxybutyrate synthesis. We found that nitrogen starvation increased specific butanol productivity up to threefold, but cessation of cell growth limited total n-butanol titers. Metabolite profiling showed that acetyl-CoA increased twofold during nitrogen starvation. Introduction of a phosphoketolase increased acetyl-CoA levels sixfold at nitrogen replete conditions and increased butanol titers from 22 to 37 mg/L at day 8. Flux balance analysis of photoautotrophic metabolism showed that a Calvin-Benson-Bassham-Phosphoketolase pathway had higher theoretical butanol productivity than CBB-Embden-Meyerhof-Parnas and a reduced butanol ATP demand. These results demonstrate that phosphoketolase overexpression and modulation of nitrogen levels are two attractive routes toward increased production of acetyl-CoA derived products in cyanobacteria and could be implemented with complementary metabolic engineering strategies.

Molecular Characterization, Gene Evolution, and Expression Analysis of the Fructose-1, 6-bisphosphate Aldolase (FBA) Gene Family in Wheat (Triticum aestivum L.)

PubMed Central

Lv, Geng-Yin; Guo, Xiao-Guang; Xie, Li-Ping; Xie, Chang-Gen; Zhang, Xiao-Hong; Yang, Yuan; Xiao, Lei; Tang, Yu-Ying; Pan, Xing-Lai; Guo, Ai-Guang; Xu, Hong

2017-01-01

Fructose-1, 6-bisphosphate aldolase (FBA) is a key plant enzyme that is involved in glycolysis, gluconeogenesis, and the Calvin cycle. It plays significant roles in biotic and abiotic stress responses, as well as in regulating growth and development processes. In the present paper, 21 genes encoding TaFBA isoenzymes were identified, characterized, and categorized into three groups: class I chloroplast/plastid FBA (CpFBA), class I cytosol FBA (cFBA), and class II chloroplast/plastid FBA. By using a prediction online database and genomic PCR analysis of Chinese Spring nulli-tetrasomic lines, we have confirmed the chromosomal location of these genes in 12 chromosomes of four homologous groups. Sequence and genomic structure analysis revealed the high identity of the allelic TaFBA genes and the origin of different TaFBA genes. Numerous putative environment stimulus-responsive cis-elements have been identified in 1,500-bp regions of TaFBA gene promoters, of which the most abundant are the light-regulated elements (LREs). Phylogenetic reconstruction using the deduced protein sequence of 245 FBA genes indicated an independent evolutionary pathway for the class I and class II groups. Although, earlier studies have indicated that class II FBA only occurs in prokaryote and fungi, our results have demonstrated that a few class II CpFBAs exist in wheat and other closely related species. Class I TaFBA was predicted to be tetramers and class II to be dimers. Gene expression analysis based on microarray and transcriptome databases suggested the distinct role of TaFBAs in different tissues and developmental stages. The TaFBA 4–9 genes were highly expressed in leaves and might play important roles in wheat development. The differential expression patterns of the TaFBA genes in light/dark and a few abiotic stress conditions were also analyzed. The results suggested that LRE cis-elements of TaFBA gene promoters were not directly related to light responses. Most TaFBA genes had higher expression levels in the roots than in the shoots when under various stresses. Class I cytosol TaFBA genes, particularly TaFBA10/12/18 and TaFBA13/16, and three class II TaFBA genes are involved in responses to various abiotic stresses. Class I CpFBA genes in wheat are apparently sensitive to different stress conditions. PMID:28659962

Light-enhanced dark respiration in leaves, isolated cells and protoplasts of various types of C4 plants.

PubMed

Parys, Eugeniusz; Jastrzebski, Hubert

2006-04-01

The rate of respiratory CO2 evolution from the leaves of Zea mays, Panicum miliaceum, and Panicum maximum, representing NADP-ME, NAD-ME, and PEP-CK types of C4 plants, respectively, was increased by approximately two to four times after a period of photosynthesis. This light-enhanced dark respiration (LEDR) was a function of net photosynthetic rate specific to plant species, and was depressed by 1% O2. When malate, aspartate, oxaloacetate or glycine solution at 50 mM concentration was introduced into the leaves instead of water, the rate of LEDR was enhanced, far less in Z. mays (by 10-25%) than in P. miliaceum (by 25-35%) or P. maximum (by 40-75%). The enhancement of LEDR under glycine was relatively stable over a period of 1 h, whereas the remaining metabolites caused its decrease following a transient increase. The metabolites reduced the net photosynthesis rate in the two Panicum species, but not in Z. mays, where this process was stimulated by glycine. The bundle sheath cells from P. miliaceum exhibited a higher rate of LEDR than those of Z. mays and P. maximum. Glycine had no effect on the respiration rate of the cells, but malate increased in cells of Z. mays and P. miliaceum by about 50% and 30%, respectively. With the exception of aspartate, which stimulated both the O2 evolution and O2 uptake in P. maximum, the remaining metabolites reduced photosynthetic O2 evolution from bundle sheath cells in Panicun species. The net O2 exchange in illuminated cells of Z. mays did not respond to CO2 or metabolites. Leaf mesophyll protoplasts of Z. mays and P. miliaceum, and bundle sheath protoplasts of Z. mays, which are unable to fix CO2 photosynthetically, also produced LEDR, but the mesophyll protoplasts, compared with bundle sheath protoplasts, required twice the time of illumination to obtain the maximal rate. The results suggest that the substrates for LEDR in C4 plants are generated during a period of illumination not only via the Calvin cycle reactions, but also by the conversion of endogenous compounds present in leaf cells. The stimulation of LEDR under glycine is discussed in relation to its direct or indirect effect on mitochondrial respiration.

The single-process biochemical reaction of Rubisco: a unified theory and model with the effects of irradiance, CO₂ and rate-limiting step on the kinetics of C₃ and C₄ photosynthesis from gas exchange.

PubMed

Farazdaghi, Hadi

2011-02-01

Photosynthesis is the origin of oxygenic life on the planet, and its models are the core of all models of plant biology, agriculture, environmental quality and global climate change. A theory is presented here, based on single process biochemical reactions of Rubisco, recognizing that: In the light, Rubisco activase helps separate Rubisco from the stored ribulose-1,5-bisphosphate (RuBP), activates Rubisco with carbamylation and addition of Mg²(+), and then produces two products, in two steps: (Step 1) Reaction of Rubisco with RuBP produces a Rubisco-enediol complex, which is the carboxylase-oxygenase enzyme (Enco) and (Step 2) Enco captures CO₂ and/or O₂ and produces intermediate products leading to production and release of 3-phosphoglycerate (PGA) and Rubisco. PGA interactively controls (1) the carboxylation-oxygenation, (2) electron transport, and (3) triosephosphate pathway of the Calvin-Benson cycle that leads to the release of glucose and regeneration of RuBP. Initially, the total enzyme participates in the two steps of the reaction transitionally and its rate follows Michaelis-Menten kinetics. But, for a continuous steady state, Rubisco must be divided into two concurrently active segments for the two steps. This causes a deviation of the steady state from the transitional rate. Kinetic models are developed that integrate the transitional and the steady state reactions. They are tested and successfully validated with verifiable experimental data. The single-process theory is compared to the widely used two-process theory of Farquhar et al. (1980. Planta 149, 78-90), which assumes that the carboxylation rate is either Rubisco-limited at low CO₂ levels such as CO₂ compensation point, or RuBP regeneration-limited at high CO₂. Since the photosynthesis rate cannot increase beyond the two-process theory's Rubisco limit at the CO₂ compensation point, net photosynthesis cannot increase above zero in daylight, and since there is always respiration at night, it leads to progressively negative daily CO₂ fixation with no possibility of oxygenic life on the planet. The Rubisco-limited theory at low CO₂ also contradicts all experimental evidence for low substrate reactions, and for all known enzymes, Rubisco included. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Plastidic Phosphoglucose Isomerase Is an Important Determinant of Starch Accumulation in Mesophyll Cells, Growth, Photosynthetic Capacity, and Biosynthesis of Plastidic Cytokinins in Arabidopsis

PubMed Central

De Diego, Nuria; Muñoz, Francisco J.; Baroja-Fernández, Edurne; Li, Jun; Ricarte-Bermejo, Adriana; Baslam, Marouane; Aranjuelo, Iker; Almagro, Goizeder; Humplík, Jan F.; Novák, Ondřej; Spíchal, Lukáš; Doležal, Karel; Pozueta-Romero, Javier

2015-01-01

Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP). In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of the pPGI encoding gene, PGI1. Starch content in pgi1-3 source leaves was ca. 10-15% of that of wild type (WT) leaves, which was similar to that of leaves of pgi1-2, a T-DNA insertion pPGI null mutant. Starch deficiency of pgi1 leaves could be reverted by the introduction of a sex1 null mutation impeding β-amylolytic starch breakdown. Although previous studies showed that starch granules of pgi1-2 leaves are restricted to both bundle sheath cells adjacent to the mesophyll and stomata guard cells, microscopy analyses carried out in this work revealed the presence of starch granules in the chloroplasts of pgi1-2 and pgi1-3 mesophyll cells. RT-PCR analyses showed high expression levels of plastidic and extra-plastidic β-amylase encoding genes in pgi1 leaves, which was accompanied by increased β-amylase activity. Both pgi1-2 and pgi1-3 mutants displayed slow growth and reduced photosynthetic capacity phenotypes even under continuous light conditions. Metabolic analyses revealed that the adenylate energy charge and the NAD(P)H/NAD(P) ratios in pgi1 leaves were lower than those of WT leaves. These analyses also revealed that the content of plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP)-pathway derived cytokinins (CKs) in pgi1 leaves were exceedingly lower than in WT leaves. Noteworthy, exogenous application of CKs largely reverted the low starch content phenotype of pgi1 leaves. The overall data show that pPGI is an important determinant of photosynthesis, energy status, growth and starch accumulation in mesophyll cells likely as a consequence of its involvement in the production of OPPP/glycolysis intermediates necessary for the synthesis of plastidic MEP-pathway derived hormones such as CKs. PMID:25811607

Monitoring the perennial martian northern polar cap with MGS MOC

NASA Astrophysics Data System (ADS)

Hale, A. Snyder; Bass, D. S.; Tamppari, L. K.

2005-04-01

We have used the Mars Global Surveyor Mars Orbiter Camera Wide Angle (MGS MOC WA) dataset to study albedo trends on the martian northern residual cap. Six study regions were selected, the Chasma Boreale source region, three regions near the center of the cap ("fish hook" region, latitude = 87°; "bottle opener" region, latitude = 87°, "steep-shallow" region, latitude = 85°), and two lower latitude regions (crater, latitude = 77°, and polar outlier, latitude = 82°), and the albedos of these six regions were examined. These regions were chosen due to their good temporal coverage in the MOC dataset, as well as having been studied by other researchers (Bass et al., 2000, Icarus 144, 382-396; Calvin and Titus, 2004, Lunar Planet. Sci. XXXV, Abstract 1455). The picture which emerges is complex. Most areas experience a combination of darkening and brightening through the northern summer; only one area consistently brightens (the polar outlier region). A good deal of interannual repeatability in each region's albedo behavior is seen, however. Possible causes for the observed complex behaviors include dust deposition from late summer storms, sintering of frost grains over the course of the summer, and cold trapping of volatiles on bright, cold surfaces.

Synthetic versatility of 2-substituted-6-methyl 2,3-dihydropyridinones in the synthesis of polyfunctional piperidine-based compounds and related β amino acid derivatives.

PubMed

Yang, Yang; Hardman, Clayton

2017-10-18

Chiral 2-substituted-6-methyl 2,3-dihydropyidinones 9, which can be facilely obtained from an asymmetric vinylogous Mannich reaction (VMR) with 1,3-bis-trimethysily enol ether, were used as versatile intermediates in constructing chiral polyfunctional piperidine-based compounds. The 6-methyl group of such compounds can be conveniently functionalized via alkylation and acylation reactions to provide efficient entries to the synthesis of a variety of chiral multi-substituted piperidine-based compounds. Further elaboration of the corresponding intermediates also provided access to polyfunctional indolizidine-based compounds. These methods were showcased in an asymmetric synthesis of 2,6-di-substituted piperidine compound 13, reported as the key intermediate in the synthesis of (+)-calvine and a natural alkaloid (-)-indolizidine 209D. Furthermore, selective C5 iodination of compound 9 enabled the installation of additional functional groups at this position. Finally, we demonstrated that the oxidative cleavage of 2-substituted-6-methyl-2,3-dihydropyidinones is a practical and efficient method for the enantioselective synthesis of β-amino acids, which can undergo further intra-molecular cyclization to give the corresponding chiral four-membered β-lactam derivatives.

Confronting zoonoses through closer collaboration between medicine and veterinary medicine (as 'one medicine').

PubMed

Kahn, Laura H; Kaplan, Bruce; Steele, James H

2007-01-01

In the 19th century, the concept of 'one medicine' was embraced by leaders in the medical and veterinary medical communities. In the 20th century, collaborative efforts between medicine and veterinary medicine diminished considerably. While there have been some notable exceptions, such as Calvin W. Schwabe's proposal for unifying human and veterinary medicine and joint efforts by the Food and Agriculture Organization and World Health Organization to control zoonotic diseases, 'one medicine' has languished in the modern milieu of clinical care, public health, and biomedical research. Risks of zoonotic disease transmission are rarely discussed in clinical care which is of particular concern if humans and/or animals are immunosuppressed. Physicians and veterinarians should advise their patients and pet-owning clients that some animals should not be pets. The risk of zoonotic disease acquisition can be considerable in the occupational setting. Collaborative efforts in biomedical research could do much to improve human and animal health. As the threat of zoonotic diseases continues to increase in the 21st century, medicine and veterinary medicine must revive 'one medicine' in order to adequately address these challenges. 'One medicine' revival strategies must involve medical and veterinary medical education, clinical care, public health and biomedical research.

Co-citation Network Analysis of Religious Texts

NASA Astrophysics Data System (ADS)

Murai, Hajime; Tokosumi, Akifumi

This paper introduces a method of representing in a network the thoughts of individual authors of dogmatic texts numerically and objectively by means of co-citation analysis and a method of distinguishing between the thoughts of various authors by clustering and analysis of clustered elements, generated by the clustering process. Using these methods, this paper creates and analyzes the co-citation networks for five authoritative Christian theologians through history (Augustine, Thomas Aquinas, Jean Calvin, Karl Barth, John Paul II). These analyses were able to extract the core element of Christian thought (Jn 1:14, Ph 2:6, Ph 2:7, Ph 2:8, Ga 4:4), as well as distinctions between the individual theologians in terms of their sect (Catholic or Protestant) and era (thinking about the importance of God's creation and the necessity of spreading the Gospel). By supplementing conventional literary methods in areas such as philosophy and theology, with these numerical and objective methods, it should be possible to compare the characteristics of various doctrines. The ability to numerically and objectively represent the characteristics of various thoughts opens up the possibilities of utilizing new information technology, such as web ontology and the Artificial Intelligence, in order to process information about ideological thoughts in the future.

Sensitivity analysis of key components in large-scale hydroeconomic models

NASA Astrophysics Data System (ADS)

Medellin-Azuara, J.; Connell, C. R.; Lund, J. R.; Howitt, R. E.

2008-12-01

This paper explores the likely impact of different estimation methods in key components of hydro-economic models such as hydrology and economic costs or benefits, using the CALVIN hydro-economic optimization for water supply in California. In perform our analysis using two climate scenarios: historical and warm-dry. The components compared were perturbed hydrology using six versus eighteen basins, highly-elastic urban water demands, and different valuation of agricultural water scarcity. Results indicate that large scale hydroeconomic hydro-economic models are often rather robust to a variety of estimation methods of ancillary models and components. Increasing the level of detail in the hydrologic representation of this system might not greatly affect overall estimates of climate and its effects and adaptations for California's water supply. More price responsive urban water demands will have a limited role in allocating water optimally among competing uses. Different estimation methods for the economic value of water and scarcity in agriculture may influence economically optimal water allocation; however land conversion patterns may have a stronger influence in this allocation. Overall optimization results of large-scale hydro-economic models remain useful for a wide range of assumptions in eliciting promising water management alternatives.

Maintaining continuity through a scientific revolution: a rereading of E. B. Wilson and T. H. Morgan on sex determination and Mendelism.

PubMed

Kingsland, Sharon E

2007-09-01

A rereading of the American scientific literature on sex determination from 1902 to 1926 leads to a different understanding of the construction of the Mendelian-chromosome theory after 1910. There was significant intellectual continuity, which has not been properly appreciated, underlying this scientific "revolution." After reexamining the relationship between the ideas of key scientists, in particular Edmund B. Wilson and Thomas Hunt Morgan, I argue that, contrary to the historical literature, Wilson and Morgan did not adopt opposing views on Mendelism and sex determination. Rather, each preferred a non-Mendelian explanation of the determination of sex. Around 1910, both integrated the Mendelian and non-Mendelian theories to create a synthetic theory. One problem was the need to avoid an overly deterministic view of sex while also accepting the validity of Mendelism. Morgan's discovery of mutations on the X chromosome takes on different significance when set in the context of the debate about sex determination, and Calvin Bridges's work on sex determination is better seen as a development of Morgan's ideas, rather than a departure from them. Conclusions point to the role of synthesis within fields as a way to advance scientific theories and reflect on the relationship between synthesis and explanatory "pluralism" in biology.

Food-web complexity across hydrothermal vents on the Azores triple junction

NASA Astrophysics Data System (ADS)

Portail, Marie; Brandily, Christophe; Cathalot, Cécile; Colaço, Ana; Gélinas, Yves; Husson, Bérengère; Sarradin, Pierre-Marie; Sarrazin, Jozée

2018-01-01

The assessment and comparison of food webs across various hydrothermal vent sites can enhance our understanding of ecological processes involved in the structure and function of biodiversity. The Menez Gwen, Lucky Strike and Rainbow vent fields are located on the Azores triple junction of the Mid-Atlantic Ridge. These fields have distinct depths (from 850 to 2320 m) and geological contexts (basaltic and ultramafic), but share similar faunal assemblages defined by the presence of foundation species that include Bathymodiolus azoricus, alvinocarid shrimp and gastropods. We compared the food webs of 13 faunal assemblages at these three sites using carbon and nitrogen stable isotope analyses (SIA). Results showed that photosynthesis-derived organic matter is a negligible basal source for vent food webs, at all depths. The contribution of methanotrophy versus autotrophy based on Calvin-Benson-Bassham (CBB) or reductive tricarboxylic acid (rTCA) cycles varied between and within vent fields according to the concentrations of reduced compounds (e.g. CH4, H2S). Species that were common to vent fields showed high trophic flexibility, suggesting weak trophic links to the metabolism of chemosynthetic primary producers. At the community level, a comparison of SIA-derived metrics between mussel assemblages from two vent fields (Menez Gwen & Lucky Strike) showed that the functional structure of food webs was highly similar in terms of basal niche diversification, functional specialization and redundancy. Coupling SIA to functional trait approaches included more variability within the analyses, but the functional structures were still highly comparable. These results suggest that despite variable environmental conditions (physico-chemical factors and basal sources) and faunal community structure, functional complexity remained relatively constant among mussel assemblages. This functional similarity may be favoured by the propensity of species to adapt to fluid variations and practise trophic flexibility. Furthermore, the different pools of species at vent fields may play similar functions in the community such as the change in composition does not affect the overall functional structure. Finally, the absence of a relationship between the functional structure and taxonomic diversity as well as the high overlap between species' isotopic niches within communities indicates that co-occuring species may have redundant functions. Therefore, the addition of species within in a functional group does not necessarily lead to more complexity. Overall, this study highlights the complexity of food webs within chemosynthetic communities and emphasizes the need to better characterize species' ecological niches and biotic interactions.

Lead stress effects on physiobiochemical activities of higher plants.

PubMed

Sengar, Rakesh Singh; Gautam, Madhu; Sengar, Rajesh Singh; Garg, Sanjay Kumar; Sengar, Kalpana; Chaudhary, Reshu

2008-01-01

Lead is a metallic pollutant emanating from various environmental sources including industrial wastes, combustion of fossil fuels, and use of agrochemicals. Lead may exist in the atmosphere as dusts, fumes, mists, and vapors, and in soil as a mineral. Soils along roadsides are rich in lead because vehicles burn leaded gasoline, which contributes to environmental lead pollution. Other important sources of lead pollution are geological weathering, industrial processing of ores and minerals, leaching of lead from solid wastes, and animal and human excreta. Lead is nondegradable, readily enters the food chain, and can subsequently endanger human and animal health. Lead is one of the most important environment pollutants and deserves the increasing attention it has received in recent decades. The present effort was undertaken to review lead stress effects on the physiobiochemical activity of higher plants. Lead has gained considerable attention as a potent heavy metal pollutant because of growing anthropogenic pressure on the environment. Lead-contaminated soils show a sharp decline in crop productivity. Lead is absorbed by plants mainly through the root system and in minor amounts through the leaves. Within the plants, lead accumulates primarily in roots, but some is translocated to aerial plant parts. Soil pH, soil particle size, cation-exchange capacity, as well as root surface area, root exudation, and mycorrhizal transpiration rate affect the availability and uptake of lead by plants. Only a limited amount of lead is translocated from roots to other organs because there are natural plant barriers in the root endodermis. At lethal concentrations, this barrier is broken and lead may enter vascular tissues. Lead in plants may form deposits of various sizes, present mainly in intercellular spaces, cell walls, and vacuoles. Small deposits of this metal are also seen in the endoplasmic reticulum, dictyosome, and dictyosome-derived vesicles. After entering the cells, lead inhibits activities of many enzymes, upsets mineral nutrition and water balance, changes the hormonal status, and affects membrane structure and permeability. Visual, nonspecific symptoms of lead toxicity are stunted growth, chlorosis, and blackening of the root system. In most cases, lead inhibition of enzyme activities results from the interaction of the metal with enzyme -SH groups. The activities of metalloenzymes may decline as a consequence of displacement of an essential metal by lead from the active sites of the enzymes. Lead decreases the photosynthetic rate of plants by distorting chloroplast ultrastructure, diminishing chlorophyll synthesis, obstructing electron transport, and inhibiting activities of Calvin cycle enzymes.

Expression of glnB and a glnB-Like Gene (glnK) in a Ribulose Bisphosphate Carboxylase/Oxygenase-Deficient Mutant of Rhodobacter sphaeroides

PubMed Central

Qian, Yilei; Tabita, F. Robert

1998-01-01

In a ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deficient mutant of Rhodobacter sphaeroides, strain 16PHC, nitrogenase activity was derepressed in the presence of ammonia under photoheterotrophic growth conditions. Previous studies also showed that reintroduction of a functional RubisCO and Calvin-Benson-Bassham (CBB) pathway suppressed the deregulation of nitrogenase synthesis in this strain. In this study, the derepression of nitrogenase synthesis in the presence of ammonia in strain 16PHC was further explored by using a glnB::lacZ fusion, since the product of the glnB gene is known to have a negative effect on ammonia-regulated nif control. It was found that glnB expression was repressed in strain 16PHC under photoheterotrophic growth conditions with either ammonia or glutamate as the nitrogen source; glutamine synthetase (GS) levels were also affected in this strain. However, when cells regained a functional CBB pathway by trans complementation of the deleted genes, wild-type levels of GS and glnB expression were restored. Furthermore, a glnB-like gene, glnK, was isolated from this organism, and its expression was found to be under tight nitrogen control in the wild type. Surprisingly, glnK expression was found to be derepressed in strain 16PHC under photoheterotrophic conditions in the presence of ammonia. PMID:9721307

[Dreaming is a hypnic state of consciousness: getting rid of the Goblot hypothesis and its modern avatars].

PubMed

Guénolé, F; Nicolas, A

2010-08-01

In the late nineteenth century, French logician Edmond Goblot first hypothesized that dreaming occurred at the moment of awakening only. Revisiting--more or less directly--Goblot's hypothesis, several contemporary authors have since renewed this unusual claim that oniric experience does not occur during sleep. So did some influential analytical philosophers (Wittgenstein, Malcolm, Dennett), with their typical formalism, and famous dream researcher Calvin Hall, who tried to provide experimental evidence for the Goblot's hypothesis. More recently, French neurobiologist Jean-Pol Tassin claimed, on the basis of controversial neurobiological and cognitive principles, that only awakening gives rise to a dream, by instantaneous shaping of information issuing of neural networks activated during preceding sleep. Actually, numerous and robust experimental data in sleep psychophysiology clearly rule out Goblot's hypothesis and its modern avatars. Thus, results of studies using nocturnal awakenings (with or without preceding hypnic stimulation), as well as observations of onirical behaviours (like rapid eye movement sleep behavior disorders, or voluntary movements of lucid dreamers) demonstrate that dreaming definitely occurs during sleep. Actually, cortical evoked potentials can be observed during sleep, which likely reflect controlled cognitive processes. Dreaming is a hypnic state of consciousness, and seems to represent a sleep thought which, although uneasily accessible, is nevertheless open to psychological investigation. Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.

Autotrophic fixation of geogenic CO2 by microorganisms contributes to soil organic matter formation and alters isotope signatures in a wetland mofette

NASA Astrophysics Data System (ADS)

Nowak, M. E.; Beulig, F.; von Fischer, J.; Muhr, J.; Küsel, K.; Trumbore, S. E.

2015-12-01

To quantify the contribution of autotrophic microorganisms to organic matter (OM) formation in soils, we investigated natural CO2 vents (mofettes) situated in a wetland in northwest Bohemia (Czech Republic). Mofette soils had higher soil organic matter (SOM) concentrations than reference soils due to restricted decomposition under high CO2 levels. We used radiocarbon (Δ14C) and stable carbon (δ13C) isotope ratios to characterize SOM and its sources in two mofettes and compared it with respective reference soils, which were not influenced by geogenic CO2. The geogenic CO2 emitted at these sites is free of radiocarbon and enriched in 13C compared to atmospheric CO2. Together, these isotopic signals allow us to distinguish C fixed by plants from C fixed by autotrophic microorganisms using their differences in 13C discrimination. We can then estimate that up to 27 % of soil organic matter in the 0-10 cm layer of these soils was derived from microbially assimilated CO2. Isotope values of bulk SOM were shifted towards more positive δ13C and more negative Δ14C values in mofettes compared to reference soils, suggesting that geogenic CO2 emitted from the soil atmosphere is incorporated into SOM. To distinguish whether geogenic CO2 was fixed by plants or by CO2 assimilating microorganisms, we first used the proportional differences in radiocarbon and δ13C values to indicate the magnitude of discrimination of the stable isotopes in living plants. Deviation from this relationship was taken to indicate the presence of microbial CO2 fixation, as microbial discrimination should differ from that of plants. 13CO2-labelling experiments confirmed high activity of CO2 assimilating microbes in the top 10 cm, where δ13C values of SOM were shifted up to 2 ‰ towards more negative values. Uptake rates of microbial CO2 fixation ranged up to 1.59 ± 0.16 μg gdw-1 d-1. We inferred that the negative δ13C shift was caused by the activity of autotrophic microorganisms using the Calvin-Benson-Bassham (CBB) cycle, as indicated from quantification of cbbL/cbbM marker genes encoding for RubisCO by quantitative polymerase chain reaction (qPCR) and by acetogenic and methanogenic microorganisms, shown present in the mofettes by previous studies. Combined Δ14C and δ13C isotope mass balances indicated that microbially derived carbon accounted for 8-27 % of bulk SOM in this soil layer. The findings imply that autotrophic microorganisms can recycle significant amounts of carbon in wetland soils and might contribute to observed radiocarbon reservoir effects influencing Δ14C signatures in peat deposits.

Targeting Autotrophic and Lithotrophic Microorganisms from Fumarolic Ice Caves of Mt. Erebus, Antarctica

NASA Astrophysics Data System (ADS)

Anitori, R.; Davis, R.; Connell, L.; Kelley, M.; Staudigel, H.; Tebo, B. M.

2011-12-01

Terrestrial and aquatic volcanic oligotrophic environments can host microorganisms that obtain their energy from reduced inorganic chemicals present in volcanic rocks and soils. We sampled basaltic rock from terrestrial Dark Oligotrophic Volcanic Ecosystems (DOVEs) located in two fumarole ice caves, Warren and Warren West, located near the summit of Mt. Erebus, Antarctica. For reference, we sampled a similar cave, Harry's Dream, which receives continuous light during the Austral summer. We report here culturing data for bacterial and eukaryotic microbes from rocky soils in these caves when targeting lithotrophic organisms using media containing reduced inorganic compounds (Mn2+, Fe2+, NH4+). In addition, to test for the possible presence of inorganic carbon fixation, we screened samples for the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) gene. Culturing of soil samples on media targeting both autotrophs and heterotrophs yielded a diverse collection of generally slow-growing colonies of bacteria (majority), fungi and non-fungal eukaryotes. Manganese(II)-oxidizing colonies were identified in Warren and Harry's Dream, and these exhibited two colony morphotypes upon subculturing. Sequencing of the PCR amplified 16S rRNA gene identified a bacterium distantly related to Pseudonocardia sp., a genus with known manganese oxidizers. Other bacteria enriched included members of the Actinobacteria, Alphaproteobacteria and Betaproteobacteria. There was a low diversity in cultured eukaryotes representing several potential undescribed species (Geomyces sp., Penicillium sp.) and isolates that may represent alternate, previously undescribed habitats and forms (Psilolechia leprosa, Alternaria alternata). One Warren isolate was a 99% 16S rRNA match to the N2 fixer Bradyrhizobium sp.; when inoculated into liquid medium specific for N2 fixers, growth was maintained upon subculture. Putative iron oxidizers were also enriched from the two DOVE caves, using slush agar iron and O2 gradient tubes. Some of the original soil isolates grown on agar without organic C grew upon subculturing into liquid medium, providing evidence for the successful enrichment of cave autotrophs. Further evidence for autotrophy was the identification of genes for the RuBisCO large subunit gene, suggesting the existence of carbon fixation via the Calvin-Benson cycle. PCR amplification was observed for the type I (cbbL) gene, but not using primers specific for the type II (cbbM) RuBisCO gene. Phylogenetic trees placed the amplified sequences in a monophyletic group deeply rooted in the 'red-like' clade within the cbbL group. Our culture-based exploration of the Mt. Erebus ice caves provides evidence for the presence of litho/autotrophic microorganisms that may be utilizing inorganic energy sources in the volcanic rocks. These results provide a novel view of life in the dark biosphere in deep volcanic settings, and augment studies of seafloor or terrestrial microbial communities in similar extreme volcanic environments.

The benefits of 'One Health' for pastoralists in Africa.

PubMed

Greter, Helena; Jean-Richard, Vreni; Crump, Lisa; Béchir, Mahamat; Alfaroukh, Idriss O; Schelling, Esther; Bonfoh, Bassirou; Zinsstag, Jakob

2014-04-23

'One health' is particularly suited to serve mobile pastoralists. Dinka pastoralists in Sudan inspired Calvin Schwabe to coin the term 'one medicine', indicating that there is no difference in paradigm between human and veterinary medicine. Our contemporary definition of 'one health' is any added value in terms of improved health of humans and animals or financial savings or environmental services resulting from a closer cooperation of human and animal health sectors. Here we present a summary of 'one health' studies with mobile pastoralists in Africa which were done in research partnership, demonstrating such an added value. Initial joint human and animal health studies revealed higher livestock vaccination coverage than in the pastoralist community, leading to joint animal and human vaccination intervention studies which demonstrated a better access to primary health care services for pastoralists in Chad. Further simultaneous animal and human serological studies showed that camel breeding was associated with human Q-fever seropositivity. In Borana communities in Ethiopia, human cases of Mycobacterium bovis infection could be related to strains isolated from cattle. A challenge remained with regard to how to assess vaccination coverage in mobile populations. With the advent of mobile phones, health and demographic surveillance could be established for mobile pastoralists and their animals. This presents vast possibilities for surveillance and control of human and animal diseases. Pastoralists prefer a 'one health' approach and therefore contribute toward the validation of this concept by showing real added value of the cooperation between human and animal health services.

A protein with an inactive pterin-4a-carbinolamine dehydratase domain is required for Rubisco biogenesis in plants.

PubMed

Feiz, Leila; Williams-Carrier, Rosalind; Belcher, Susan; Montano, Monica; Barkan, Alice; Stern, David B

2014-12-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) plays a critical role in sustaining life by catalysis of carbon fixation in the Calvin-Benson pathway. Incomplete knowledge of the assembly pathway of chloroplast Rubisco has hampered efforts to fully delineate the enzyme's properties, or seek improved catalytic characteristics via directed evolution. Here we report that a Mu transposon insertion in the Zea mays (maize) gene encoding a chloroplast dimerization co-factor of hepatocyte nuclear factor 1 (DCoH)/pterin-4α-carbinolamine dehydratases (PCD)-like protein is the causative mutation in a seedling-lethal, Rubisco-deficient mutant named Rubisco accumulation factor 2 (raf2-1). In raf2 mutants newly synthesized Rubisco large subunit accumulates in a high-molecular weight complex, the formation of which requires a specific chaperonin 60-kDa isoform. Analogous observations had been made previously with maize mutants lacking the Rubisco biogenesis proteins RAF1 and BSD2. Chemical cross-linking of maize leaves followed by immunoprecipitation with antibodies to RAF2, RAF1 or BSD2 demonstrated co-immunoprecipitation of each with Rubisco small subunit, and to a lesser extent, co-immunoprecipitation with Rubisco large subunit. We propose that RAF2, RAF1 and BSD2 form transient complexes with the Rubisco small subunit, which in turn assembles with the large subunit as it is released from chaperonins. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Status of the Prototype Pulsed Photonuclear Assessment (PPA) Inspection System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prototype Photonuclear Inspection Technoloby - An

Prototype Photonuclear Inspection Technology – An Integrated Systems Approach* James L. Jonesa, Daren R. Normana, Kevin J. Haskella, James W. Sterbentza, Woo Y. Yoona, Scott M. Watsona, James T. Johnsona, John M. Zabriskiea, Calvin E. Mossb, Frank Harmonc a – Idaho National Laboratory, P.O. Box 1625-2802, Idaho Falls, Idaho 83415-2802 b – Los Alamos National Laboratory, P.O. Box 1663, MS B228, Los Alamos, New Mexico, 87585 c – Idaho State University, 1500 Alvin Ricken Dr., Pocatello, Idaho 83201 Active interrogation technologies are being pursued in order to address many of today’s challenging inspection requirements related to both nuclear and non-nuclearmore » material detection. The Idaho National Laboratory, along with the Los Alamos National Laboratory and the Idaho State University’s Idaho Accelerator Center, continue to develop electron accelerator-based, photonuclear inspection technologies for the detection of shielded nuclear material within air-, rail-, and especially, maritime-cargo containers. This paper presents an overview and status of the prototype Pulsed Photonuclear Assessment (PPA) inspection system and its ability to detect shielded nuclear material by focusing on the integration of three major detection system components: delayed neutron measurement, delayed gamma-ray measurements, and a transmission, gray-scale mapping for shield material detection. Areas of future development and advancement within each detection component will be presented. *Supported in part by the Department of Homeland Security under DOE-ID Contract Number DE-AC07-99ID13727. POC: James L. Jones, 208-526-1730« less

An open source hydroeconomic model for California's water supply system: PyVIN

NASA Astrophysics Data System (ADS)

Dogan, M. S.; White, E.; Herman, J. D.; Hart, Q.; Merz, J.; Medellin-Azuara, J.; Lund, J. R.

2016-12-01

Models help operators and decision makers explore and compare different management and policy alternatives, better allocate scarce resources, and predict the future behavior of existing or proposed water systems. Hydroeconomic models are useful tools to increase benefits or decrease costs of managing water. Bringing hydrology and economics together, these models provide a framework for different disciplines that share similar objectives. This work proposes a new model to evaluate operation and adaptation strategies under existing and future hydrologic conditions for California's interconnected water system. This model combines the network structure of CALVIN, a statewide optimization model for California's water infrastructure, along with an open source solver written in the Python programming language. With the flexibilities of the model, reservoir operations, including water supply and hydropower, groundwater pumping, and the Delta water operations and requirements can now be better represented. Given time series of hydrologic inputs to the model, typical outputs include urban, agricultural and wildlife refuge water deliveries and shortage costs, conjunctive use of surface and groundwater systems, and insights into policy and management decisions, such as capacity expansion and groundwater management policies. Water market operations also represented in the model, allocating water from lower-valued users to higher-valued users. PyVIN serves as a cross-platform, extensible model to evaluate systemwide water operations. PyVIN separates data from the model structure, enabling model to be easily applied to other parts of the world where water is a scarce resource.

The holistic grail: possible implications of an initial mistake in the reading of digital mammograms

NASA Astrophysics Data System (ADS)

Mello-Thoms, Claudia

2009-02-01

In 1967 Ulric Neisser, studying how laypeople examined pictures, hypothesized that image perception occurs in two stages, a pre-attentive stage in which the entire image is processed in parallel, where a 'holistic' view of what is being displayed is formed, and a secondary stage in which items or groups of items are examined by focal attention. Later, the proponents of Neisser's theory suggested that the pre-attentive stage may bias the selection of the areas that will be subjected to further analysis. This is easily seen in those dual interpretation figures; once one 'sees' the figure in a certain way, it is very hard to instruct the eye-brain system to let go of that perception and 'see' the figure in the alternative way. In medical image perception, Harold Kundel and Calvin Nodine proposed a model of medical image interpretation that is based upon Neisser's two stages, and have become so convinced of the influence of the 'holistic' view on the subsequent reading of the image that they have recently questioned the traditional framework that determines how lesions are found. In other words, as opposed to the traditional view of SEARCH THE IMAGE - DETECT A POSSIBLE FINDING - IDENTIFY THE FINDING - DECIDE WHAT TO DO ABOUT THE IMAGE, Kundel and Nodine have recently suggested a new framework: DETECT A POSSIBLE FINDING - IDENTIFY THE FINDING - SEARCH THE IMAGE - DECIDE WHAT TO DO ABOUT THE IMAGE. In light of this significant switch, we decided to investigate what happens when the 'holistic' view is incorrect.

Measurement of Ecosystem Metabolism across Climatic and Vegetation Gradients in California

NASA Astrophysics Data System (ADS)

DuBois, S.; Serbin, S.; Desai, A. R.; Kruger, E.; Kingdon, C.; Goulden, M.; Townsend, P. A.

2013-12-01

Terrestrial ecosystem models require information on vegetation structure, phenology, demographics, biochemistry, radiation properties, and physiology in order to accurately simulate the responses of ecosystem functioning to global change and disturbances. These models generally depend on a small number of intensive, fine-scaled point-based measurements from eddy covariance towers, detailed vegetation surveys, literature values, and site-scale data assimilation techniques to improve model calibration. However, the limited geographic and/or temporal scope of measurements can lead to inadequate model generalizations of modeled carbon (C), water, and energy fluxes across broad regions and relevant time periods. Remote sensing approaches, particularly imaging spectroscopy (IS) and thermal infrared (TIR) data, have the potential to provide the broad-scale spatial and temporal dynamics in many important vegetation properties related to ecosystem functioning. As part of the ongoing NASA HyspIRI Airborne Campaign (http://hyspiri.jpl.nasa.gov/airborne) we are assessing the potential of IS+TIR to generate spatially explicit estimates of two important parameters characterizing plant photosynthetic capacity: the maximum rate of CO2 carboxylation by RuBisCo (Vcmax), and the maximum rate of electron transport required for the regeneration of RuBP needed in Calvin Cycle processes (Jmax). These estimates are based on recent evidence that both properties can be predicted at the leaf level using spectroscopy techniques (Ainsworth et al. 2013 [http://tinyurl.com/n5xnzjg]; Serbin et al. 2012 [http://tinyurl.com/mhocmlz]). It follows that estimation of these variables from remotely sensed IS+TIR (i.e. AVIRIS & MASTER) could facilitate the prediction of seasonal C assimilation across large areas using data from the anticipated HyspIRI satellite mission. Our research focuses on two climate-elevation transects in California, which span a vegetation gradient from coastal sage and chaparral to oak woodlands and closed-canopy coniferous forests, as well as agro-ecosystems located throughout the Central and Imperial Valleys. We are also comparing remotely sensed estimates of ecosystem photosynthetic capacity with C flux data from a series of 10 eddy covariance towers. Results from the 2013 field season highlight the large range in sampled vegetation structure, optical properties (i.e. reflectance and transmittance) and physiology (i.e. Vcmax, Jmax, and cholorphyll fluorescence). Using approaches similar to Serbin et al. (2012) we have confirmed the ability of spectroscopy to estimate Vcmax and Jmax across these diverse and structurally complex vegetation types. Ecosystem products, such as gross primary productivity, estimated from flux towers highlight the relationship between climatic parameters and vegetation productivity. Multiple data-years allow this relationship to be examined under various climatic forcings including drought and heat stress. Based on these preliminary results, our next step is to scale leaf-level information to AVIRIS footprints using radiative transfer and statistical modeling approaches with ecosystem modeling in order to assess the IS data products against flux tower observations.

Some like it hot: understanding the limits of life using hyperthermophilic microbes

NASA Astrophysics Data System (ADS)

Holden, James

Hyperthermophiles are those microorganisms that grow optimally above 80° C and have the highest known growth temperatures of any life (up to 121° C in pure culture). The study of hyperthermophiles has helped to constrain our understanding of the limits in two ways. First and most obvious, it provides upper temperature boundaries for where life may exist. In general, upper temperature limits vary with life forms: eukaryotes (55° C), photosynthetic bacteria (72° C), non-photosynthetic bacteria (100° C), methanogens (110° C), sulfur reduction (113° C), and iron reduction (121° C). The incubation of natural microbial assemblages suggests that life may exist at temperatures of at least 125° C, and studies of extracellular hydrolases show that the impact of life processes extend up to 130-140° C. Several factors have been implicated that permit hyperthermophilic life. Proteins are stabilized at high temperatures through increased rigidity brought on by several separate factors (e.g., increased hydrogen bonding, oligomerization, shortened loop structures). DNA is stabilized by a hyperthermophile-specific topoisomerase that introduces positive supercoils into the double helix and by DNA binding proteins that help to prevent strand melting. Hyperthermophiles also possess a remarkably efficient DNA repair mechanism. Lipids are stabilized by using ether linkages of isoprenoid alcohol hydrocarbons to the glycerol head and a high degree of covalent cross-linking between opposing lipids in the membrane bilayer. However, in order for life to exist above 140° C, organisms would require mechanisms to prevent denaturation within individual amino acids, nucleic acids, and other low molecular weight cofactors within the cytoplasm. The second way that the study of hyperthermophiles has helped to constrain the limits of life is by understanding how life exists in geothermal environments and deep within the Earth's crust without oxygen or sunlight. Hyperthermophiles can serve as the primary producers in these environments using volcanically-derived H2 and CO2 as energy and carbon sources and CO2 assimilation pathways other than the Calvin cycle. Insoluble iron, CO2 , and various sulfur compounds can serve as terminal electron acceptors. Unlike commonly-studied mesophilic bacteria, iron respiration in some hyperthermophiles does not require polyheme c-type cytochromes in the membrane, and direct contact with iron is not necessary for electron transfer. Environmental factors such as pH and reduction potential have a significant impact on the kinds of metabolisms that occur, and thermodynamic modeling suggests that minimum H2 activity increases with temperature in order to meet the minimum energy requirement for growth. These factors lead to a non-stochastic distribution of hyperthermophile metabolic types in any given environment. Taken together, these parameters will greatly aid in modeling growth in a variety of environments that will serve the exploration for life beyond our planet.

Regulators of nonsulfur purple phototrophic bacteria and the interactive control of CO2 assimilation, nitrogen fixation, hydrogen metabolism and energy generation.

PubMed

Dubbs, James M; Tabita, F Robert

2004-06-01

For the metabolically diverse nonsulfur purple phototrophic bacteria, maintaining redox homeostasis requires balancing the activities of energy supplying and energy-utilizing pathways, often in the face of drastic changes in environmental conditions. These organisms, members of the class Alphaproteobacteria, primarily use CO2 as an electron sink to achieve redox homeostasis. After noting the consequences of inactivating the capacity for CO2 reduction through the Calvin-Benson-Bassham (CBB) pathway, it was shown that the molecular control of many additional important biological processes catalyzed by nonsulfur purple bacteria is linked to expression of the CBB genes. Several regulator proteins are involved, with the two component Reg/Prr regulatory system playing a major role in maintaining redox poise in these organisms. Reg/Prr was shown to be a global regulator involved in the coordinate control of a number of metabolic processes including CO2 assimilation, nitrogen fixation, hydrogen metabolism and energy-generation pathways. Accumulating evidence suggests that the Reg/Prr system senses the oxidation/reduction state of the cell by monitoring a signal associated with electron transport. The response regulator RegA/PrrA activates or represses gene expression through direct interaction with target gene promoters where it often works in concert with other regulators that can be either global or specific. For the key CO2 reduction pathway, which clearly triggers whether other redox balancing mechanisms are employed, the ability to activate or inactivate the specific regulator CbbR is of paramount importance. From these studies, it is apparent that a detailed understanding of how diverse regulatory elements integrate and control metabolism will eventually be achieved.

Plants as Indicators of Past and Present Zones of Upwelling Soil CO2 at the ZERT Facility

NASA Astrophysics Data System (ADS)

Apple, M. E.; Sharma, B.; Zhou, X.; Shaw, J. A.; Dobeck, L.; Cunnningham, A.; Spangler, L.; ZERT Team

2011-12-01

By their very nature, photosynthetic plants are sensitive and responsive to CO2, which they fix during the Calvin-Benson cycle. Responses of plants to CO2 are valuable tools in the surface detection of upwelling and leaking CO2 from carbon sequestration fields. Plants exposed to upwelling CO2 rapidly exhibit signs of stress such as changes in stomatal conductance, hyperspectral signatures, pigmentation, and viability (Lakkaraju et al. 2010; Male et al. 2010). The Zero Emission Research and Technology (ZERT) site in Bozeman, MT is an experimental facility for surface detection of CO2 where 0.15 ton/day of CO2 was released (7/19- 8/15/2010, and 7/18 - 8/15/2011) from a 100m horizontal injection well, (HIW), 1.5 m underground with deliberate leaks of CO2 at intervals, and from a vertical injector, (VIW), (6/3-6/24/2010). Soil CO2 concentrations reached 16%. Plants at ZERT include Taraxacum officinale (Dandelion), Dactylis glomerata (Orchard Grass), Poa pratensis, (Kentucky Bluegrass), Phleum pratense (Timothy), Bromus japonicus (Japanese Brome), Medicago sativa (Alfalfa) and Cirsium arvense (Canadian Thistle). Dandelion leaves above the zones of upwelling CO2 at the HIW and the VIW changed color from green to reddish-purple (indicative of an increase in anthocyanins) to brown as they senesced within two weeks of CO2 injection. Their increased stomatal conductance along with their extensive surface area combined to make water loss occur quickly following injection of CO2. Xeromorphic grass leaves were not as profoundly affected, although they did exhibit changes in stomatal conductance, accelerated loss of chlorophyll beyond what would normally occur with seasonal senescence, and altered hyperspectral signatures. Within two weeks of CO2 injection at the HIW and the VIW, hot spots formed, which are circular zones of visible leaf senescence that appear at zones of upwelling CO2. The hot spots became more pronounced as the CO2 injection continued, and were detectable until obscured by snow in the fall and winter. Residual hot spots were visible in the spring after a summer CO2 injection. At both the HIW and the VIW, dandelions were less abundant, if not scarce, in the hot spots when quantified the next year. We mounted a Star-Dot web camera on a scaffold, from which the camera photographs the area each day at noon. The camera remains in place year round and obtains images of the current and residual hot spots, and the growth, color changes, and senescence of the plants. We also quantified percent coverage of plant species along the HIW and the VIW. At the VIW, which received CO2 in 2010 but not in 2011, the site of the 2010 hot spot was detectable in 2011 as a scarcity of dandelion leaves. Therefore, previous, or antecedent, conditions influenced the distribution of species at the VIW and do not depend on continuous injection of CO2. Sudden and long-term shifts in species composition have important ecological implications and may serve as a means of surface detection of upwelling CO2.

Leaf photosynthesis/respiration relationships of different tree species in the northwestern part of Russia.

NASA Astrophysics Data System (ADS)

Pridacha, V.; Sazonova, T.; Olchev, A.

2012-04-01

Measurements of leaf photosynthesis, respiration and stomatal conductance of Norway spruce (Picea abies (L.) Karst), Silver (Betula pendula Roth), White (Betula pubescens) and Karelian (Betula pendula var. carelica) birches were provided using the portable photosynthesis system LI-6400 (Li-Cor, USA) on the experimental plots of the Forest research Institute of Karelian Research Center of RAS in Petrozavodsk, Russia. LI-6400 allows to provide the measurements of photosynthesis and respiration rates of individual leaves at various PAR, temperatures, humidity and concentration of CO2 in the measuring chamber. During the field campaigns in 2011 the CO2 and light response curves of photosynthesis of leaves under different air temperatures as well as the temperature response functions of dark respiration (Rd) of the leaves of different species were estimated. The measuring program is include also the measurements of nitrogen content in leaves. The method suggested by Sharkey et al (2007) was used to estimate the maximal velocity of Rubisco for carboxylation (Vcmax), the rate of electron transport at light saturation (Jmax), photorespiratory compensation point as well as the rate of use of triose phosphates (TPU) that characterizes the availability of internal inorganic phosphates (Ci) in leaves for Calvin's cycle. It was assumed that the initial slope of the relationship between leaf photosynthesis rate and CO2 concentration in sub-stomatal air space (Ci < 200 ppm) can be considered as an area of Rubisco limitation of photosynthesis. The upper part of CO2 response curve from approximately 300 ppm and higher is influenced by, first of all, the rate of regeneration of RuBP, and after that by availability of inorganic phosphate in leaves. The temperature dependences of Vcmax, Jmax and TPU were estimated using the statistical analysis of Vcmax and Jmax data set using equations suggested by Medlin et al (2002). Temperature dependence function of TPU was derived using algorithm proposed by Sharkey et al (2007). The results of field measurements in summer 2011 show a relatively weak differences among Vcmax, Jmax and TPU, and also Rd for Silver, White and Karelian birches. The maximal values of Vcmax (T=25° C) are obtained for the Karelian birch (Vcmax (T=25° C) = 117 μmol m-2 s-1), and the minimum values - for the Silver birch (Vcmax (T=25° C) = 97 μmol m-2 s-1). The maximum values Jmax (T=25° C) are obtained for the White birch (Jmax (T=25° C) = 164 μmol m-2 s-1), and minimum also for the Silver birch (Jmax (T=25° C) = 157 μmol m-2 s-1). Values TPU max are varied from 11.0 to 12.3 μmol m-2 s-1, and Rd (T=25° C) - from 2.0 to 2.4 μmol m-2 s-1. The results of provided leaf photosynthesis, respiration and stomatal conductance measurements were used in the process-based Mixfor-SVAT model (Olchev et al 2002, 2008) to derive the possible response of CO2/H2O budgets of Karelian forest ecosystems to future climatic changes. The study was supported by grants (11-04-01622-a and 09-04-00299-a) of the Russian Foundation of Basic Research (RFBR).

DOE Office of Scientific and Technical Information (OSTI.GOV)

James C. Liao

This project is a collaboration with F. R. Tabita of Ohio State. Our major goal is to understand the factors and regulatory mechanisms that influence hydrogen production. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Our part of the project was to develop a modeling technique to investigate the metabolic network in connection to hydrogen production and regulation. Organisms must balance the pathways that generate and consume reducing powermore » in order to maintain redox homeostasis to achieve growth. Maintaining this homeostasis in the nonsulfur purple photosynthetic bacteria is a complex feat with many avenues that can lead to balance, as these organisms possess versatile metabolic capabilities including anoxygenic photosynthesis, aerobic or anaerobic respiration, and fermentation. Growth is achieved by using H{sub 2} as an electron donor and CO{sub 2} as a carbon source during photoautotrophic and chemoautotrophic growth, where CO{sub 2} is fixed via the Calvin-Benson-Bassham (CBB) cycle. Photoheterotrophic growth can also occur when alternative organic carbon compounds are utilized as both the carbon source and electron donor. Regardless of the growth mode, excess reducing equivalents generated as a result of oxidative processes, must be transferred to terminal electron acceptors, thus insuring that redox homeostasis is maintained in the cell. Possible terminal acceptors include O{sub 2}, CO{sub 2}, organic carbon, or various oxyanions. Cells possess regulatory mechanisms to balance the activity of the pathways which supply energy, such as photosynthesis, and those that consume energy, such as CO{sub 2} assimilation or N{sub 2} fixation. The major route for CO{sub 2} assimilation is the CBB reductive pentose phosphate pathway, whose key enzyme is ribulose 1,5-biphosphate carboxylase/oxygenase (RubisCO). In addition to providing virtually all cellular carbon during autotrophic metabolism, RubisCO-mediated CO{sub 2} assimilation is also very important for nonsulfur purple photosynthetic bacteria under photoheterotrophic growth conditions since CO{sub 2} becomes the major electron sink under these conditions. In this work, Ensemble Modeling (EM) was developed to examine the behavior of CBB-compromised RubisCO knockout mutant strains of the nonsulfur purple photosynthetic bacterium Rhodobacter sphaeroides. Mathematical models of metabolism can be a great aid in studying the effects of large perturbations to the system, such as the inactivation of RubisCO. Due to the complex and highly-interconnected nature of these networks, it is not a trivial process to understand what the effect of perturbations to the metabolic network will be, or vice versa, what enzymatic perturbations are necessary to yield a desired effect. Flux distribution is controlled by multiple enzymes in the network, often indirectly linked to the pathways of interest. Further, depending on the state of the cell and the environmental conditions, the effect of a perturbation may center around how it effects the carbon flow in the network, the balancing of cofactors, or both. Thus, it is desirable to develop mathematical models to describe, understand, and predict network behavior. Through the development of such models, one may gain the ability to generate a set of testable hypotheses for system behavior.« less

Crystalline and amorphous H2O on Charon

NASA Astrophysics Data System (ADS)

Dalle Ore, Cristina M.; Cruikshank, Dale P.; Grundy, Will M.; Ennico, Kimberly; Olkin, Catherine B.; Stern, S. Alan; Young, Leslie A.; Weaver, Harold A.

2015-11-01

Charon, the largest satellite of Pluto, is a gray-colored icy world covered mostly in H2O ice, with spectral evidence for NH3, as previously reported (Cook et al. 2007, Astrophys. J. 663, 1406-1419 Merlin, et al. 2010, Icarus, 210, 930; Cook, et al. 2014, AAS/Division for Planetary Sciences Meeting Abstracts, 46, #401.04). Images from the New Horizons spacecraft reveal a surface with terrains of widely different ages and a moderate degree of localized coloration. The presence of H2O ice in its crystalline form (Brown & Calvin 2000 Science 287, 107-109; Buie & Grundy 2000 Icarus 148, 324-339; Merlin et al, 2010) along with NH3 is consistent with a fresh surface.The phase of H2O ice is a key tracer of variations in temperature and physical conditions on the surface of outer Solar System objects. At Charon’s surface temperature H2O is expected to be amorphous, but ground-based observations (e.g., Merlin et al. 2010) show a clearly crystalline signature. From laboratory experiments it is known that amorphous H2O ice becomes crystalline at temperatures of ~130 K. Other mechanisms that can change the phase of the ice from amorphous to crystalline include micro-meteoritic bombardment (Porter et al. 2010, Icarus, 208, 492) or resurfacing processes such as cryovolcanism.New Horizons observed Charon with the LEISA imaging spectrometer, part of the Ralph instrument (Reuter, D.C., Stern, S.A., Scherrer, J., et al. 2008, Space Science Reviews, 140, 129). Making use of high spatial resolution (better than 10 km/px) and spectral resolving power of 240 in the wavelength range 1.25-2.5 µm, and 560 in the range 2.1-2.25 µm, we report on an analysis of the phase of H2O ice on parts of Charon’s surface with a view to investigate the recent history and evolution of this small but intriguing object.This work was supported by NASA’s New Horizons project.

Microbial acceleration of aerobic pyrite oxidation at circumneutral pH.

PubMed

Percak-Dennett, E; He, S; Converse, B; Konishi, H; Xu, H; Corcoran, A; Noguera, D; Chan, C; Bhattacharyya, A; Borch, T; Boyd, E; Roden, E E

2017-09-01

Pyrite (FeS 2 ) is the most abundant sulfide mineral on Earth and represents a significant reservoir of reduced iron and sulfur both today and in the geologic past. In modern environments, oxidative transformations of pyrite and other metal sulfides play a key role in terrestrial element partitioning with broad impacts to contaminant mobility and the formation of acid mine drainage systems. Although the role of aerobic micro-organisms in pyrite oxidation under acidic-pH conditions is well known, to date there is very little known about the capacity for aerobic micro-organisms to oxidize pyrite at circumneutral pH. Here, we describe two enrichment cultures, obtained from pyrite-bearing subsurface sediments, that were capable of sustained cell growth linked to pyrite oxidation and sulfate generation at neutral pH. The cultures were dominated by two Rhizobiales species (Bradyrhizobium sp. and Mesorhizobium sp.) and a Ralstonia species. Shotgun metagenomic sequencing and genome reconstruction indicated the presence of Fe and S oxidation pathways in these organisms, and the presence of a complete Calvin-Benson-Bassham CO 2 fixation system in the Bradyrhizobium sp. Oxidation of pyrite resulted in thin (30-50 nm) coatings of amorphous Fe(III) oxide on the pyrite surface, with no other secondary Fe or S phases detected by electron microscopy or X-ray absorption spectroscopy. Rates of microbial pyrite oxidation were approximately one order of magnitude higher than abiotic rates. These results demonstrate the ability of aerobic microbial activity to accelerate pyrite oxidation and expand the potential contribution of micro-organisms to continental sulfide mineral weathering around the time of the Great Oxidation Event to include neutral-pH environments. In addition, our findings have direct implications for the geochemistry of modern sedimentary environments, including stimulation of the early stages of acid mine drainage formation and mobilization of pyrite-associated metals. © 2017 John Wiley & Sons Ltd.

Energy Efficient Buildings, Salt Lake County, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnett, Kimberly

2012-04-30

Executive Summary Salt Lake County's Solar Photovoltaic Project - an unprecedented public/private partnership Salt Lake County is pleased to announce the completion of its unprecedented solar photovoltaic (PV) installation on the Calvin R. Rampton Salt Palace Convention Center. This 1.65 MW installation will be one the largest solar roof top installations in the country and will more than double the current installed solar capacity in the state of Utah. Construction is complete and the system will be operational in May 2012. The County has accomplished this project using a Power Purchase Agreement (PPA) financing model. In a PPA model amore » third-party solar developer will finance, develop, own, operate, and maintain the solar array. Salt Lake County will lease its roof, and purchase the power from this third-party under a long-term Power Purchase Agreement contract. In fact, this will be one of the first projects in the state of Utah to take advantage of the recent (March 2010) legislation which makes PPA models possible for projects of this type. In addition to utilizing a PPA, this solar project will employ public and private capital, Energy Efficiency and Conservation Block Grants (EECBG), and public/private subsidized bonds that are able to work together efficiently because of the recent stimulus bill. The project also makes use of recent changes to federal tax rules, and the recent re-awakening of private capital markets that make a significant public-private partnership possible. This is an extremely innovative project, and will mark the first time that all of these incentives (EECBG grants, Qualified Energy Conservation Bonds, New Markets tax credits, investment tax credits, public and private funds) have been packaged into one project. All of Salt Lake County's research documents and studies, agreements, and technical information is available to the public. In addition, the County has already shared a variety of information with the public through webinars, site tours, presentations, and written correspondence.« less

The Krebs Uric Acid Cycle: A Forgotten Krebs Cycle.

PubMed

Salway, Jack G

2018-05-25

Hans Kornberg wrote a paper entitled 'Krebs and his trinity of cycles' commenting that every school biology student knows of the Krebs cycle, but few know that Krebs discovered two other cycles. These are (i) the ornithine cycle (urea cycle), (ii) the citric acid cycle (tricarboxylic acid or TCA cycle), and (iii) the glyoxylate cycle that was described by Krebs and Kornberg. Ironically, Kornberg, codiscoverer of the 'glyoxylate cycle', overlooked a fourth Krebs cycle - (iv) the uric acid cycle. Copyright © 2018 Elsevier Ltd. All rights reserved.

Absorption Heat Pump Cycles

NASA Astrophysics Data System (ADS)

Kunugi, Yoshifumi; Kashiwagi, Takao

Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

The Effect of Cycling Intensity on Cycling Economy During Seated and Standing Cycling.

PubMed

Arkesteijn, Marco; Jobson, Simon; Hopker, James; Passfield, Louis

2016-10-01

Previous research has shown that cycling in a standing position reduces cycling economy compared with seated cycling. It is unknown whether the cycling intensity moderates the reduction in cycling economy while standing. The aim was to determine whether the negative effect of standing on cycling economy would be decreased at a higher intensity. Ten cyclists cycled in 8 different conditions. Each condition was either at an intensity of 50% or 70% of maximal aerobic power at a gradient of 4% or 8% and in the seated or standing cycling position. Cycling economy and muscle activation level of 8 leg muscles were recorded. There was an interaction between cycling intensity and position for cycling economy (P = .03), the overall activation of the leg muscles (P = .02), and the activation of the lower leg muscles (P = .05). The interaction showed decreased cycling economy when standing compared with seated cycling, but the difference was reduced at higher intensity. The overall activation of the leg muscles and the lower leg muscles, respectively, increased and decreased, but the differences between standing and seated cycling were reduced at higher intensity. Cycling economy was lower during standing cycling than seated cycling, but the difference in economy diminishes when cycling intensity increases. Activation of the lower leg muscles did not explain the lower cycling economy while standing. The increased overall activation, therefore, suggests that increased activation of the upper leg muscles explains part of the lower cycling economy while standing.

Vapor Compression Cycle Design Program (CYCLE_D)

National Institute of Standards and Technology Data Gateway

SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

A comparative look at sunspot cycles

NASA Technical Reports Server (NTRS)

Wilson, R. M.

1984-01-01

On the basis of cycles 8 through 20, spanning about 143 years, observations of sunspot number, smoothed sunspot number, and their temporal properties were used to compute means, standard deviations, ranges, and frequency of occurrence histograms for a number of sunspot cycle parameters. The resultant schematic sunspot cycle was contrasted with the mean sunspot cycle, obtained by averaging smoothed sunspot number as a function of time, tying all cycles (8 through 20) to their minimum occurence date. A relatively good approximation of the time variation of smoothed sunspot number for a given cycle is possible if sunspot cycles are regarded in terms of being either HIGH- or LOW-R(MAX) cycles or LONG- or SHORT-PERIOD cycles, especially the latter. Linear regression analyses were performed comparing late cycle parameters with early cycle parameters and solar cycle number. The early occurring cycle parameters can be used to estimate later occurring cycle parameters with relatively good success, based on cycle 21 as an example. The sunspot cycle record clearly shows that the trend for both R(MIN) and R(MAX) was toward decreasing value between cycles 8 through 14 and toward increasing value between cycles 14 through 20. Linear regression equations were also obtained for several measures of solar activity.

Effects of a cycle training course on children's cycling skills and levels of cycling to school.

PubMed

Ducheyne, Fabian; De Bourdeaudhuij, Ilse; Lenoir, Matthieu; Cardon, Greet

2014-06-01

The primary aim of the present study was to evaluate the short- and longer-term effects of a cycle training on children's cycling skills. A second aim of the study was to examine the effects of a cycle training, with and without parental involvement, on levels of cycling to school and on parental attitudes towards cycling. Three participating schools were randomly assigned to the "intervention" (25 children), the "intervention plus parent" (34 children) or "control" condition (35 children). A cycle training (four sessions of 45 min) took place only in the intervention schools. Parents in the "intervention plus parent" condition were asked to assist their child in completing weekly homework tasks. Children's cycling skills were assessed, using a practical cycling test. All participating children also received a short parental questionnaire on cycling behavior and parental attitudes towards cycling. Assessments took place at baseline, within 1 week after the last session and at 5-months follow-up. Repeated measure analyses were conducted to evaluate the effects of the cycle training. Children's total cycling skill score increased significantly more from pre to post and from pre to 5-months follow-up in the intervention group than in the control group. On walking with the bicycle (F=1.6), cycling in a straight line (F=2.6), cycling a slalom (F=1.9), cycling over obstacles (F=2.1), cycling on a sloping surface (F=1.7) and dismounting the bicycle (F=2.0), the cycle training had no effect. For all other cycling skills, significant improvements were observed on short- and longer-term. No significant intervention effects were found on children's cycling to school levels (F=1.9) and parental attitudes towards cycling. The cycle training course was effective in improving children's cycling skills and the improvements were maintained 5 months later. However, the cycle training course was not effective in increasing children's cycling to school levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 1: Open-cycle gas turbines

NASA Technical Reports Server (NTRS)

Brown, D. H.; Corman, J. C.

1976-01-01

Ten energy conversion systems are defined and analyzed in terms of efficiency. These include: open-cycle gas turbine recuperative; open-cycle gas turbine; closed-cycle gas turbine; supercritical CO2 cycle; advanced steam cycle; liquid metal topping cycle; open-cycle MHD; closed-cycle inert gas MHD; closed-cycle liquid metal MHD; and fuel cells. Results are presented.

Predictive modeling and reducing cyclic variability in autoignition engines

DOEpatents

Hellstrom, Erik; Stefanopoulou, Anna; Jiang, Li; Larimore, Jacob

2016-08-30

Methods and systems are provided for controlling a vehicle engine to reduce cycle-to-cycle combustion variation. A predictive model is applied to predict cycle-to-cycle combustion behavior of an engine based on observed engine performance variables. Conditions are identified, based on the predicted cycle-to-cycle combustion behavior, that indicate high cycle-to-cycle combustion variation. Corrective measures are then applied to prevent the predicted high cycle-to-cycle combustion variation.

Development of Improved LOX-Compatible Laminated Gasket Composite

DTIC Science & Technology

1966-08-01

Braided Teflon 2. Bleached fluorocarbon felt 3. Teflon and asbestos fibers 4. Teflon and ceramic fibers 5. Teflon and glass fibers 6. Viton A and asbestos 7...fluorinated ethylene- propylene (Teflon FEP), polychlorotrifluoroethylene films (Aclar - Kel F), and fluorocarbon elastomers (Viton A - Fluorel, etc...2nd 10th CYCLE CYCLE CYCLE CYCLE CYCLE CYCLE CYCLE CYCLE CYCLE FILLED FLUOROCARBON GLASS FILLED TEFLON FLUOROCARBON LAMINATE ELASTOMER Figure 21

Differences in physical environmental characteristics between adolescents' actual and shortest cycling routes: a study using a Google Street View-based audit.

PubMed

Verhoeven, Hannah; Van Hecke, Linde; Van Dyck, Delfien; Baert, Tim; Van de Weghe, Nico; Clarys, Peter; Deforche, Benedicte; Van Cauwenberg, Jelle

2018-05-29

The objective evaluation of the physical environmental characteristics (e.g. speed limit, cycling infrastructure) along adolescents' actual cycling routes remains understudied, although it may provide important insights into why adolescents prefer one cycling route over another. The present study aims to gain insight into the physical environmental characteristics determining the route choice of adolescent cyclists by comparing differences in physical environmental characteristics between their actual cycling routes and the shortest possible cycling routes. Adolescents (n = 204; 46.5% boys; 14.4 ± 1.2 years) recruited at secondary schools in and around Ghent (city in Flanders, northern part of Belgium) were instructed to wear a Global Positioning System device in order to identify cycling trips. For all identified cycling trips, the shortest possible route that could have been taken was calculated. Actual cycling routes that were not the shortest possible cycling routes were divided into street segments. Segments were audited with a Google Street View-based tool to assess physical environmental characteristics along actual and shortest cycling routes. Out of 160 actual cycling trips, 73.1% did not differ from the shortest possible cycling route. For actual cycling routes that were not the shortest cycling route, a speed limit of 30 km/h, roads having few buildings with windows on the street side and roads without cycle lane were more frequently present compared to the shortest possible cycling routes. A mixed land use, roads with commercial destinations, arterial roads, cycle lanes separated from traffic by white lines, small cycle lanes and cycle lanes covered by lighting were less frequently present along actual cycling routes compared to the shortest possible cycling routes. Results showed that distance mainly determines the route along which adolescents cycle. In addition, adolescents cycled more along residential streets (even if no cycle lane was present) and less along busy, arterial roads. Local authorities should provide shortcuts free from motorised traffic to meet adolescents' preference to cycle along the shortest route and to avoid cycling along arterial roads.

K-6 Science Curriculum.

ERIC Educational Resources Information Center

Blueford, J. R.; And Others

A unified science approach is incorporated in this K-6 curriculum mode. The program is organized into six major cycles. These include: (1) science, math, and technology cycle; (2) universe cycle; (3) life cycle; (4) water cycle; (5) plate tectonics cycle; and (6) rock cycle. An overview is provided of each cycle's major concepts. The topic…

Supercritical CO2 Power Cycles: Design Considerations for Concentrating Solar Power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neises, Ty; Turchi, Craig

2014-09-01

A comparison of three supercritical CO2 Brayton cycles: the simple cycle, recompression cycle and partial-cooling cycle indicates the partial-cooling cycle is favored for use in concentrating solar power (CSP) systems. Although it displays slightly lower cycle efficiency versus the recompression cycle, the partial-cooling cycle is estimated to have lower total recuperator size, as well as a lower maximum s-CO2 temperature in the high-temperature recuperator. Both of these effects reduce recuperator cost. Furthermore, the partial-cooling cycle provides a larger temperature differential across the turbine, which translates into a smaller, more cost-effective thermal energy storage system. The temperature drop across the turbinemore » (and by extension, across a thermal storage system) for the partial-cooling cycle is estimated to be 23% to 35% larger compared to the recompression cycle of equal recuperator conductance between 5 and 15 MW/K. This reduces the size and cost of the thermal storage system. Simulations by NREL and Abengoa Solar indicate the partial-cooling cycle results in a lower LCOE compared with the recompression cycle, despite the former's slightly lower cycle efficiency. Advantages of the recompression cycle include higher thermal efficiency and potential for a smaller precooler. The overall impact favors the use of a partial-cooling cycle for CSP compared to the more commonly analyzed recompression cycle.« less

Transitions between refrigeration regions in extremely short quantum cycles

NASA Astrophysics Data System (ADS)

Feldmann, Tova; Kosloff, Ronnie

2016-05-01

The relation between the geometry of refrigeration cycles and their performance is explored. The model studied is based on a coupled spin system. Small cycle times, termed sudden refrigerators, develop coherence and inner friction. We explore the interplay between coherence and energy of the working medium employing a family of sudden cycles with decreasing cycle times. At the point of maximum coherence the cycle changes geometry. This region of cycle times is characterized by a dissipative resonance where heat is dissipated both to the hot and cold baths. We rationalize the change of geometry of the cycle as a result of a half-integer quantization which maximizes coherence. From this point on, increasing or decreasing the cycle time, eventually leads to refrigeration cycles. The transition point between refrigerators and short circuit cycles is characterized by a transition from finite to singular dynamical temperature. Extremely short cycle times reach a universal limit where all cycles types are equivalent.

75 FR 23572 - Airworthiness Directives; Airbus Model A300 B2-1C, B2-203, B2K-3C, B4-103, B4-203, B4-2C...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-04

... cycles 6,700 flight 80A3 or Pratt & Whitney engines. flight cycles \\1\\. flight cycles or \\2\\. cycles or...-200 airplanes with GE CF6- 18,000 total 19,500 total 250 flight cycles 5,800 flight 80C2 engines... flight cycles 6,700 flight Pratt & Whitney JT9D engines. flight cycles \\1\\. flight cycles or \\2\\. cycles...

Prostaglandin F2alpha-induced estrus in ewes exhibiting estrous cycles of different duration.

PubMed

Cárdenas, Horacio; Wiley, Todd M; Pope, William F

2004-07-01

Effects of prostaglandin F(2alpha) (PGF(2alpha)), administered during the mid-luteal phase of the estrous cycle, were examined in ewes exhibiting estrous cycles classified as short (< or =16.5 days, short-cycle ewes, n = 10) or long (> or =18 days, long-cycle ewes, n = 9) based on the durations of two estrous cycles (cycles -2 and -1) before treatment. The ewes received (i.m.) 20mg of PGF(2alpha) on day 10 of the third estrous cycle (cycle 0) followed, 36 h later, by 25 microg of gonadotropin releasing hormone (GnRH) to time the events of ovulation. Duration of subsequent estrous cycles +1 and +2 were recorded, and then the ewes were treated with the same combination of PGF(2alpha) and GnRH beginning on day 10 of estrous cycle +3. Ovaries were recovered 6h after GnRH administration to assess development of pre-ovulatory follicles. The proportion of ewes that exhibited estrus after PGF(2alpha) and GnRH treatment on cycle 0 was not different (P > 0.05) between short- and long-cycle ewes. Onset of estrus occurred sooner (P < 0.05) after PGF(2alpha) injection in short-cycle ewes than in long-cycle ewes (1.9 +/- 0.1 days and 2.3 +/- 0.1 days, duration of cycle 0 was 11.9 and 12.3 days, respectively). Duration of estrous cycle +1 was 1.2 days longer (P < 0.01) than cycle -1 in short-cycle ewes. However, duration of estrous cycle +1 did not change (P > 0.05) after PGF(2alpha) and GnRH administration in ewes having long cycles. Pre-ovulatory follicles did not differ (P > 0.05) in numbers, diameter, layers of granulosa cells nor concentrations of progesterone and estradiol-17beta in follicular fluid between short- and long-cycle ewes after PGF(2alpha) and GnRH treatment. In conclusion, ewes having short or long estrous cycles responded differently to PGF(2alpha) and GnRH treatment with respect to the interval to onset of estrus and duration of the subsequent estrous cycle.

On the Importance of Cycle Minimum in Sunspot Cycle Prediction

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1996-01-01

The characteristics of the minima between sunspot cycles are found to provide important information for predicting the amplitude and timing of the following cycle. For example, the time of the occurrence of sunspot minimum sets the length of the previous cycle, which is correlated by the amplitude-period effect to the amplitude of the next cycle, with cycles of shorter (longer) than average length usually being followed by cycles of larger (smaller) than average size (true for 16 of 21 sunspot cycles). Likewise, the size of the minimum at cycle onset is correlated with the size of the cycle's maximum amplitude, with cycles of larger (smaller) than average size minima usually being associated with larger (smaller) than average size maxima (true for 16 of 22 sunspot cycles). Also, it was found that the size of the previous cycle's minimum and maximum relates to the size of the following cycle's minimum and maximum with an even-odd cycle number dependency. The latter effect suggests that cycle 23 will have a minimum and maximum amplitude probably larger than average in size (in particular, minimum smoothed sunspot number Rm = 12.3 +/- 7.5 and maximum smoothed sunspot number RM = 198.8 +/- 36.5, at the 95-percent level of confidence), further suggesting (by the Waldmeier effect) that it will have a faster than average rise to maximum (fast-rising cycles have ascent durations of about 41 +/- 7 months). Thus, if, as expected, onset for cycle 23 will be December 1996 +/- 3 months, based on smoothed sunspot number, then the length of cycle 22 will be about 123 +/- 3 months, inferring that it is a short-period cycle and that cycle 23 maximum amplitude probably will be larger than average in size (from the amplitude-period effect), having an RM of about 133 +/- 39 (based on the usual +/- 30 percent spread that has been seen between observed and predicted values), with maximum amplitude occurrence likely sometime between July 1999 and October 2000.

Will Solar Cycles 25 and 26 Be Weaker than Cycle 24?

NASA Astrophysics Data System (ADS)

Javaraiah, J.

2017-11-01

The study of variations in solar activity is important for understanding the underlying mechanism of solar activity and for predicting the level of activity in view of the activity impact on space weather and global climate. Here we have used the amplitudes (the peak values of the 13-month smoothed international sunspot number) of Solar Cycles 1 - 24 to predict the relative amplitudes of the solar cycles during the rising phase of the upcoming Gleissberg cycle. We fitted a cosine function to the amplitudes and times of the solar cycles after subtracting a linear fit of the amplitudes. The best cosine fit shows overall properties (periods, maxima, minima, etc.) of Gleissberg cycles, but with large uncertainties. We obtain a pattern of the rising phase of the upcoming Gleissberg cycle, but there is considerable ambiguity. Using the epochs of violations of the Gnevyshev-Ohl rule (G-O rule) and the `tentative inverse G-O rule' of solar cycles during the period 1610 - 2015, and also using the epochs where the orbital angular momentum of the Sun is steeply decreased during the period 1600 - 2099, we infer that Solar Cycle 25 will be weaker than Cycle 24. Cycles 25 and 26 will have almost same strength, and their epochs are at the minimum between the current and upcoming Gleissberg cycles. In addition, Cycle 27 is expected to be stronger than Cycle 26 and weaker than Cycle 28, and Cycle 29 is expected to be stronger than both Cycles 28 and 30. The maximum of Cycle 29 is expected to represent the next Gleissberg maximum. Our analysis also suggests a much lower value (30 - 40) for the maximum amplitude of the upcoming Cycle 25.

On the Relation Between Spotless Days and the Sunspot Cycle

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2005-01-01

Spotless days are examined as a predictor for the size and timing of a sunspot cycle. For cycles 16-23 the first spotless day for a new cycle, which occurs during the decline of the old cycle, is found to precede minimum amplitude for the new cycle by about approximately equal to 34 mo, having a range of 25-40 mo. Reports indicate that the first spotless day for cycle 24 occurred in January 2004, suggesting that minimum amplitude for cycle 24 should be expected before April 2007, probably sometime during the latter half of 2006. If true, then cycle 23 will be classified as a cycle of shorter period, inferring further that cycle 24 likely will be a cycle of larger than average minimum and maximum amplitudes and faster than average rise, peaking sometime in 2010.

Cost-effectiveness of treatment strategies in women with PCOS who do not conceive after six cycles of clomiphene citrate.

PubMed

Moolenaar, Lobke M; Nahuis, Marleen J; Hompes, Peter G; van der Veen, Fulco; Mol, Ben Willem J

2014-05-01

This study evaluated the cost-effectiveness of treatments for women with polycystic ovary syndrome (PCOS) who ovulate on clomiphene citrate but do not conceive after six cycles. A decision-analytic framework was developed for six scenarios: (1) three cycles of IVF; (2) continuation of clomiphene citrate for six cycles, followed by three cycles of IVF in case of no birth; (3) six cycles of gonadotrophins and three cycles of IVF; (4) 12 cycles of gonadotrophins and three cycles of IVF; (5) continuation of clomiphene citrate for six cycles, six cycles of gonadotrophins and three cycles of IVF; (6) continuation of clomiphene citrate for six cycles, 12 cycles of gonadotrophins and three cycles of IVF. Two-year cumulative birth rates were 58%, 74%, 89%, 97%, 93% and 98% and costs per couple were € 9518, € 7530, € 9711, € 9764, € 7651 and € 7684 for scenarios 1-6, respectively. Scenario 2 was the lowest cost option. The extra cost for at least one live birth in scenario 5 was € 629 and in scenario 6 € 630. In these subjects, continuation of treatment for six cycles of clomiphene citrate, 6 or 12 cycles of gonadotrophins and IVF is potentially cost-effective. These results should be confirmed in a randomized clinical trial. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Characteristics of utility cyclists in Queensland, Australia: an examination of the associations between individual, social, and environmental factors and utility cycling.

PubMed

Sahlqvist, Shannon L; Heesch, Kristiann C

2012-08-01

Initiatives to promote utility cycling in countries like Australia and the US, which have low rates of utility cycling, may be more effective if they first target recreational cyclists. This study aimed to describe patterns of utility cycling and examine its correlates, among cyclists in Queensland, Australia. An online survey was administered to adult members of a state-based cycling community and advocacy group (n=1813). The survey asked about demographic characteristics and cycling behavior, motivators and constraints. Utility cycling patterns were described, and logistic regression modeling was used to examine associations between utility cycling and other variables. Forty-seven percent of respondents reported utility cycling: most did so to commute (86%). Most journeys (83%) were >5 km. Being male, younger, employed full-time, or university-educated increased the likelihood of utility cycling (P<.05). Perceiving cycling to be a cheap or a convenient form of transport was associated with utility cycling (P<.05). The moderate rate of utility cycling among recreational cyclists highlights a potential to promote utility cycling among this group. To increase utility cycling, strategies should target female and older recreational cyclists and focus on making cycling a cheap and convenient mode of transport.

Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

PubMed

Nariai, Yukiko; Hayashi, Saki; Morita, Satoru; Umemura, Yoshitaka; Tainaka, Kei-ichi; Sota, Teiji; Cooley, John R; Yoshimura, Jin

2011-04-06

Periodical cicadas (Magicicada spp.) in the USA are divided into three species groups (-decim, -cassini, -decula) of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect) could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods") with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

Gender differences in recreational and transport cycling: a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints

PubMed Central

2012-01-01

Background Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and in motivators and constraints to cycling, separately for recreational and transport cycling. Methods Adult members of a Queensland, Australia, community bicycling organization completed an online survey about their cycling patterns; cycling purposes; and personal, social and perceived environmental motivators and constraints (47% response rate). Closed and open-end questions were completed. Using the quantitative data, multivariable linear, logistic and ordinal regression models were used to examine associations between gender and cycling patterns, motivators and constraints. The qualitative data were thematically analyzed to expand upon the quantitative findings. Results In this sample of 1862 bicyclists, men were more likely than women to cycle for recreation and for transport, and they cycled for longer. Most transport cycling was for commuting, with men more likely than women to commute by bicycle. Men were more likely to cycle on-road, and women off-road. However, most men and women did not prefer to cycle on-road without designed bicycle lanes, and qualitative data indicated a strong preference by men and women for bicycle-only off-road paths. Both genders reported personal factors (health and enjoyment related) as motivators for cycling, although women were more likely to agree that other personal, social and environmental factors were also motivating. The main constraints for both genders and both cycling purposes were perceived environmental factors related to traffic conditions, motorist aggression and safety. Women, however, reported more constraints, and were more likely to report as constraints other environmental factors and personal factors. Conclusion Differences found in men’s and women’s cycling patterns, motivators and constraints should be considered in efforts to promote cycling, particularly in efforts to increase cycling for transport. PMID:22958280

Gender differences in recreational and transport cycling: a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints.

PubMed

Heesch, Kristiann C; Sahlqvist, Shannon; Garrard, Jan

2012-09-08

Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and in motivators and constraints to cycling, separately for recreational and transport cycling. Adult members of a Queensland, Australia, community bicycling organization completed an online survey about their cycling patterns; cycling purposes; and personal, social and perceived environmental motivators and constraints (47% response rate). Closed and open-end questions were completed. Using the quantitative data, multivariable linear, logistic and ordinal regression models were used to examine associations between gender and cycling patterns, motivators and constraints. The qualitative data were thematically analyzed to expand upon the quantitative findings. In this sample of 1862 bicyclists, men were more likely than women to cycle for recreation and for transport, and they cycled for longer. Most transport cycling was for commuting, with men more likely than women to commute by bicycle. Men were more likely to cycle on-road, and women off-road. However, most men and women did not prefer to cycle on-road without designed bicycle lanes, and qualitative data indicated a strong preference by men and women for bicycle-only off-road paths. Both genders reported personal factors (health and enjoyment related) as motivators for cycling, although women were more likely to agree that other personal, social and environmental factors were also motivating. The main constraints for both genders and both cycling purposes were perceived environmental factors related to traffic conditions, motorist aggression and safety. Women, however, reported more constraints, and were more likely to report as constraints other environmental factors and personal factors. Differences found in men's and women's cycling patterns, motivators and constraints should be considered in efforts to promote cycling, particularly in efforts to increase cycling for transport.

Analysis of multiple pulse NMR in solids. III

NASA Technical Reports Server (NTRS)

Burum, D. P.; Rhim, W. K.

1979-01-01

The paper introduces principles which greatly simplify the process of designing and analyzing compound pulse cycles. These principles are demonstrated by applying them to the design and analysis of several cycles, including a 52-pulse cycle; this pulse cycle combines six different REV-8 cycles and has substantially more resolving power than previously available techniques. Also, a new 24-pulse cycle is introduced which combines three different REV-8 cycles and has a resolving ability equivalent to that of the 52-pulse cycle. The principle of pulse-cycle decoupling provides a method for systematically combining pulse groups into compound cycles in order to achieve enhanced performance. This method is illustrated by a logical development from the two-pulse solid echo sequence to the WAHUHA (Waugh et al., 1968), the REV-8, and the new 24-pulse and 52-pulse cycles, along with the 14-pulse and 12-pulse cycles. Proton chemical shift tensor components for several organic solids, measured by using the 52-pulse cycle, are reported without detailed discussion.

Bipolar mood cycles and lunar tidal cycles.

PubMed

Wehr, T A

2018-04-01

In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon's semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies ('supermoons'). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles' being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon's semi-diurnal gravimetric tides might have driven the patients' bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker's phase-relationship to sleep in a manner that is known to cause switches from depression to mania.

Gauging the Nearness and Size of Cycle Minimum

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1997-01-01

By definition, the conventional onset for the start of a sunspot cycle is the time when smoothed sunspot number (i.e., the 12-month moving average) has decreased to its minimum value (called minimum amplitude) prior to the rise to its maximum value (called maximum amplitude) for the given sunspot cycle. On the basis (if the modern era sunspot cycles 10-22 and on the presumption that cycle 22 is a short-period cycle having a cycle length of 120 to 126 months (the observed range of short-period modern era cycles), conventional onset for cycle 23 should not occur until sometime between September 1996 and March 1997, certainly between June 1996 and June 1997, based on the 95-percent confidence level deduced from the mean and standard deviation of period for the sample of six short-pei-iod modern era cycles. Also, because the first occurrence of a new cycle, high-latitude (greater than or equal to 25 degrees) spot has always preceded conventional onset of the new cycle by at least 3 months (for the data-available interval of cycles 12-22), conventional onset for cycle 23 is not expected until about August 1996 or later, based on the first occurrence of a new cycle 23, high-latitude spot during the decline of old cycle 22 in May 1996. Although much excitement for an earlier-occurring minimum (about March 1996) for cycle 23 was voiced earlier this year, the present study shows that this exuberance is unfounded. The decline of cycle 22 continues to favor cycle 23 minimum sometime during the latter portion of 1996 to the early portion of 1997.

On the prospect of using butterfly diagrams to predict cycle minimum

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1987-01-01

Features enabling the prediction of the beginning and the length of a solar cycle, in addition to the turning points in the period-growth dichotomy, have been identified based on butterfly diagrams for the period from 1874 to the present. The present results indicate that cycle 21 will be a long-period cycle ending after July 1987. On the assumption that April 1985 was the first occurrence of high latitude new cycle (cycle 22) spots during the decline of cycle 21 (the old cycle), it is suggested that the last occurrence of high latitude old cycle spots was September 1983 and that the minimum for cycle 22 will be about 1986.7 + or - 1.1 yr.

Focused training boosts revenue cycle skills, accountability.

PubMed

Richmond, Craig

2011-09-01

In 2009, the MetroHealth System took its first steps toward creating a comprehensive revenue cycle university, with the goal of developing revenue cycle staff talent and achieving best-in-class revenue cycle operations. MetroHealth became a beta site for HFMA's online Credentialed Revenue Cycle Representative (CRCR) program, and asked its revenue cycle leaders to present classes on key revenue cycle issues. As of June 2011, 62 percent of 122 revenue cycle employees who had taken the CRCR course passed the exam. The CRCR designation is now a prerequisite for career advancement in certain revenue cycle areas at MetroHealth.

Does the Current Minimum Validate (or Invalidate) Cycle Prediction Methods?

NASA Technical Reports Server (NTRS)

Hathaway, David H.

2010-01-01

This deep, extended solar minimum and the slow start to Cycle 24 strongly suggest that Cycle 24 will be a small cycle. A wide array of solar cycle prediction techniques have been applied to predicting the amplitude of Cycle 24 with widely different results. Current conditions and new observations indicate that some highly regarded techniques now appear to have doubtful utility. Geomagnetic precursors have been reliable in the past and can be tested with 12 cycles of data. Of the three primary geomagnetic precursors only one (the minimum level of geomagnetic activity) suggests a small cycle. The Sun's polar field strength has also been used to successfully predict the last three cycles. The current weak polar fields are indicative of a small cycle. For the first time, dynamo models have been used to predict the size of a solar cycle but with opposite predictions depending on the model and the data assimilation. However, new measurements of the surface meridional flow indicate that the flow was substantially faster on the approach to Cycle 24 minimum than at Cycle 23 minimum. In both dynamo predictions a faster meridional flow should have given a shorter cycle 23 with stronger polar fields. This suggests that these dynamo models are not yet ready for solar cycle prediction.

Joy, exercise, enjoyment, getting out: a qualitative study of older people's experience of cycling in Sydney, Australia.

PubMed

Zander, Alexis; Passmore, Erin; Mason, Chloe; Rissel, Chris

2013-01-01

Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Seventeen adults who aged 50-75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants' confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment) and improved physical health. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

Application of the Maximum Amplitude-Early Rise Correlation to Cycle 23

NASA Technical Reports Server (NTRS)

Willson, Robert M.; Hathaway, David H.

2004-01-01

On the basis of the maximum amplitude-early rise correlation, cycle 23 could have been predicted to be about the size of the mean cycle as early as 12 mo following cycle minimum. Indeed, estimates for the size of cycle 23 throughout its rise consistently suggested a maximum amplitude that would not differ appreciably from the mean cycle, contrary to predictions based on precursor information. Because cycle 23 s average slope during the rising portion of the solar cycle measured 2.4, computed as the difference between the conventional maximum (120.8) and minimum (8) amplitudes divided by the ascent duration in months (47), statistically speaking, it should be a cycle of shorter period. Hence, conventional sunspot minimum for cycle 24 should occur before December 2006, probably near July 2006 (+/-4 mo). However, if cycle 23 proves to be a statistical outlier, then conventional sunspot minimum for cycle 24 would be delayed until after July 2007, probably near December 2007 (+/-4 mo). In anticipation of cycle 24, a chart and table are provided for easy monitoring of the nearness and size of its maximum amplitude once onset has occurred (with respect to the mean cycle and using the updated maximum amplitude-early rise relationship).

Characterization of oocyte retrieval cycles with empty zona pellucida.

PubMed

Oride, Aki; Kanasaki, Haruhiko; Hara, Tomomi; Ohta, Hiroko; Kyo, Satoru

2018-01-01

To identify the factors that characterize cycles with empty zona pellucida (EZP). Thirty-six oocyte retrieval cycles from which EZP were collected and another 36 cycles from which no EZP was collected were compared. The patients were divided into three groups: those with no EZP collected during any cycle, those with EZP collected during all cycles, and those experiencing cycles both with and without EZP. The mean number of oocytes collected per cycle was higher in the cycles with EZP than without EZP. The fertilization rate of the collected oocytes and the rate of good embryo formation were significantly lower in the cycles with EZP. No significant difference was observed between the three groups in terms of age, number of oocytes collected, or hormone levels before and after the oocyte retrieval. The fertilization and pregnancy rates were highest in the patients with no EZP being collected during any cycle, followed by those experiencing cycles both with and without EZP, and then by those with EZP collected during all cycles. The observation of lower fertilization, poor embryo formation, and a low pregnancy rate in the patients with EZP suggests the poor quality of oocytes that were collected with EZP in the same cycle.

Joy, Exercise, Enjoyment, Getting out: A Qualitative Study of Older People's Experience of Cycling in Sydney, Australia

PubMed Central

Passmore, Erin; Mason, Chloe; Rissel, Chris

2013-01-01

Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants' confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment) and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising. PMID:23864869

On long-term periodicities in the sunspot record

NASA Technical Reports Server (NTRS)

Wilson, R. M.

1984-01-01

Sunspot records are systematically maintained, with the knowledge that an 11 year average period exists since about 1850. Thus, the sunspot record of highest quality and considered to be the most reliable is that of cycle eight through the present. On the basis of cycles 8 through 20, various combinations of sine curves were used to approximate the observed R sub MAX values (where R sub MAX is the smoothed sunspot number at cycle maximum). It is found that a three component sinusoidal function, having an 11 cycle and a 2 cycle variation on a 90 cycle periodicity, yields computed R sub MAX values which fit, reasonably well, observed R sub MAX values for the modern sunspot cycles. Extrapolation of the empirical functions forward in time allows for the projection of values of R sub MAX for cycles 21 and 22. For cycle 21, the function projects a value of 157.3, very close to the actually observed value of 164.5. For cycle 22, the function projects a value of about 107. Linear regressions applied to cycle 22 indicate a long-period cycle (cycle duration 132 months). An extensive bibliography on techniques used to estimate the time dependent behavior of sunspot cycles is provided.

A thermodynamic review of cryogenic refrigeration cycles for liquefaction of natural gas

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung

2015-12-01

A thermodynamic review is presented on cryogenic refrigeration cycles for the liquefaction process of natural gas. The main purpose of this review is to examine the thermodynamic structure of various cycles and provide a theoretical basis for selecting a cycle in accordance with different needs and design criteria. Based on existing or proposed liquefaction processes, sixteen ideal cycles are selected and the optimal conditions to achieve their best thermodynamic performance are investigated. The selected cycles include standard and modified versions of Joule-Thomson (JT) cycle, Brayton cycle, and their combined cycle with pure refrigerants (PR) or mixed refrigerants (MR). Full details of the cycles are presented and discussed in terms of FOM (figure of merit) and thermodynamic irreversibility. In addition, a new method of nomenclature is proposed to clearly identify the structure of cycles by abbreviation.

Fractographic evaluation of creep effects on strain-controlled fatigue-cracking of AISI 304LC and 316 stainless steel

NASA Technical Reports Server (NTRS)

Oldrieve, R. E.

1978-01-01

Analysis of high temperature low cycle fatigue of AISI 304LC and 316 stainless steels by the method of strainrange partitioning results in four separate strainrange versus life relationships, depending upon the way in which creep-strain and plastic strain are combined within a cycle. Fractography is used in this investigation of the creep-fatigue interaction associated with these cycles. The PP and PC-cycle fractures were transgranular. The PC-cycle resulted in fewer cycles of initiation and shorter total cyclic life for the same applied inelastic strainrange. The CC-cycle had mixed transgranular and intergranular fracture, fewer cycles of initiation and shorter cycle life than PP or PC. The CP-cycle had fully integranular cracking, and failed in fewer cycles than were required for cracks to initate for PP,PC, and CC.

Nuclear Aircraft Feasibility Study. Volume 1

DTIC Science & Technology

1975-03-01

Cycle 6-36 6.2.2 Helium Mass Flow 6-42 6.2.3 Fan Pressure Ratio 6-42 6.2.4 Regenerative Cycle Application 6-43 6.2.5 Brayton Cycle...6-8 Engine Systems Summary 6-9 T-S Diagram of Ideal Brayton Cycle 6-13 T-S Diagram of Brayton Cycle for Turbofan Engine 6-15 Comparison of... Brayton Closed Cycle Thermodynamic Analysis 6-50 6.2.8-1 Indirect Cycle Gas Circulation System 6-53 6.2.8-2 Gas Turbine Generator — Pump Cycle

Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process.

PubMed

Laranjeiro, Ricardo; Tamai, T Katherine; Letton, William; Hamilton, Noémie; Whitmore, David

2018-04-01

Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles.

Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process

PubMed Central

Tamai, T. Katherine; Letton, William; Hamilton, Noémie; Whitmore, David

2018-01-01

Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles. PMID:29444612

Does a frozen embryo transfer ameliorate the effect of elevated progesterone seen in fresh transfer cycles?

PubMed

Healy, Mae Wu; Patounakis, George; Connell, Matt T; Devine, Kate; DeCherney, Alan H; Levy, Michael J; Hill, Micah J

2016-01-01

To compare the effect of progesterone (P) on the day of trigger in fresh assisted reproduction technology (ART) transfer cycles versus its effect on subsequent frozen embryo transfer (FET) cycles. Retrospective cohort study. Large private ART practice. Fresh autologous and FET cycles from 2011-2013. None. Live birth. A paired analysis of patients who underwent both a fresh transfer and subsequent FET cycle and an unpaired analysis of data from all fresh transfer cycles and all FET cycles were performed. We analyzed 1,216 paired and 4,124 unpaired cycles, and P was negatively associated with birth in fresh but not FET cycles in all analyses. Interaction testing of P and cycle type indicated P had a different association with birth in fresh versus FET cycles. When P was ≥ 2 ng/mL at the time of trigger, live birth was more likely in FET versus fresh cycles in the paired analysis (47% vs. 10%), in the unpaired analysis (51% vs. 14%), and in unpaired, good blastocyst only transfer subgroup (51% vs. 29%). Live birth was similar in FET cycles, with P ≥ 2 ng/mL versus P < 2 ng/mL (51% vs. 49%). Conversely, live birth was lower in fresh cycles, with P ≥ 2 ng/mL versus P <2 ng/mL (15% vs. 45%). Elevated P levels on the day of trigger during the initial fresh cycle were negatively associated with live birth in the fresh transfer cycles but not in subsequent FET cycles. Freezing embryos and performing a subsequent FET cycle ameliorates the effect of elevated P on live-birth rates. Published by Elsevier Inc.

Effect of Repeated Freeze-Thaw Cycles on Beef Quality and Safety

PubMed Central

Rahman, Mohammad Hafizur; Hossain, Mohammad Mujaffar; Rahman, Syed Mohammad Ehsanur; Hashem, Mohammad Abul

2014-01-01

The objectives of this study were to know the effect of repeated freeze-thaw cycles of beef on the sensory, physicochemical quality and microbiological assessment. The effects of three successive freeze-thaw cycles on beef forelimb were investigated comparing with unfrozen fresh beef for 75 d by keeping at −20±1℃. The freeze-thaw cycles were subjected to three thawing methods and carried out to know the best one. As the number of freeze-thaw cycles increased color and odor declined significantly before cook within the cycles and tenderness, overall acceptability also declined among the cycles after cook by thawing methods. The thawing loss increased and dripping loss decreased significantly (p<0.05). Water holding capacity (WHC) increased (p<0.05) until two cycles and then decreased. Cooking loss increased in cycle 1 and 3, but decreased in cycle 2. pH decreased significantly (p<0.05) among the cycles. Moreover, drip loss, cooking loss and WHC were affected (p<0.05) by thawing methods within the cycles. 2-Thiobarbituric acid (TBARS) value increased (p<0.05) gradually within the cycles and among the cycles by thawing methods. Total viable bacteria, total coliform and total yeast-mould count decreased significantly (p<0.05) within and among the cycles in comparison to the initial count in repeated freeze-thaw cycles. As a result, repeated freeze-thaw cycles affected the sensory, physicochemical and microbiological qua- lity of beef, causing the deterioration of beef quality, but improved the microbiological quality. Although repeated freeze-thaw cycles did not affect much on beef quality and safety but it may be concluded that repeated freeze and thaw should be minimized in terms of beef color for commercial value and WHC and tenderness/juiciness for eating quality. PMID:26761286

Diary of a Wimpy Cycle

NASA Technical Reports Server (NTRS)

Hathaway, David; Upton, Lisa

2013-01-01

The cause of the low and extended minimum in solar activity between Sunspot Cycles 23 and 24 was the small size of Sunspot Cycle 24 itself - small cycles start late and leave behind low minima. Cycle 24 is small because the polar fields produced during Cycle 23 were substantially weaker than those produced during the previous cycles and those (weak) polar fields are the seeds for the activity of the following cycle. Here we discuss the observed characteristics of Cycle 24 and contrast them to the characteristics of previous cycles. We present observations and Magnetic Flux Transport simulations with data assimilated from SOHO/MDI and SDO/HMI that help to explain these differences and point the way to predictions of future activity levels.

Various supercritical carbon dioxide cycle layouts study for molten carbonate fuel cell application

NASA Astrophysics Data System (ADS)

Bae, Seong Jun; Ahn, Yoonhan; Lee, Jekyoung; Lee, Jeong Ik

2014-12-01

Various supercritical carbon dioxide (S-CO2) cycles for a power conversion system of a Molten Carbonate Fuel Cell (MCFC) hybrid system are studied in this paper. Re-Compressing Brayton (RCB) cycle, Simple Recuperated Brayton (SRB) cycle and Simple Recuperated Transcritical (SRT) cycle layouts were selected as candidates for this study. In addition, a novel concept of S-CO2 cycle which combines Brayton cycle and Rankine cycle is proposed and intensively studied with other S-CO2 layouts. A parametric study is performed to optimize the total system to be compact and to achieve wider operating range. Performances of each S-CO2 cycle are compared in terms of the thermal efficiency, net electricity of the MCFC hybrid system and approximate total volumes of each S-CO2 cycle. As a result, performance and total physical size of S-CO2 cycle can be better understood for MCFC S-CO2 hybrid system and especially, newly suggested S-CO2 cycle shows some success.

Automated respiratory cycles selection is highly specific and improves respiratory mechanics analysis.

PubMed

Rigo, Vincent; Graas, Estelle; Rigo, Jacques

2012-07-01

Selected optimal respiratory cycles should allow calculation of respiratory mechanic parameters focusing on patient-ventilator interaction. New computer software automatically selecting optimal breaths and respiratory mechanics derived from those cycles are evaluated. Retrospective study. University level III neonatal intensive care unit. Ten mins synchronized intermittent mandatory ventilation and assist/control ventilation recordings from ten newborns. The ventilator provided respiratory mechanic data (ventilator respiratory cycles) every 10 secs. Pressure, flow, and volume waves and pressure-volume, pressure-flow, and volume-flow loops were reconstructed from continuous pressure-volume recordings. Visual assessment determined assisted leak-free optimal respiratory cycles (selected respiratory cycles). New software graded the quality of cycles (automated respiratory cycles). Respiratory mechanic values were derived from both sets of optimal cycles. We evaluated quality selection and compared mean values and their variability according to ventilatory mode and respiratory mechanic provenance. To assess discriminating power, all 45 "t" values obtained from interpatient comparisons were compared for each respiratory mechanic parameter. A total of 11,724 breaths are evaluated. Automated respiratory cycle/selected respiratory cycle selections agreement is high: 88% of maximal κ with linear weighting. Specificity and positive predictive values are 0.98 and 0.96, respectively. Averaged values are similar between automated respiratory cycle and ventilator respiratory cycle. C20/C alone is markedly decreased in automated respiratory cycle (1.27 ± 0.37 vs. 1.81 ± 0.67). Tidal volume apparent similarity disappears in assist/control: automated respiratory cycle tidal volume (4.8 ± 1.0 mL/kg) is significantly lower than for ventilator respiratory cycle (5.6 ± 1.8 mL/kg). Coefficients of variation decrease for all automated respiratory cycle parameters in all infants. "t" values from ventilator respiratory cycle data are two to three times higher than ventilator respiratory cycles. Automated selection is highly specific. Automated respiratory cycle reflects most the interaction of both ventilator and patient. Improving discriminating power of ventilator monitoring will likely help in assessing disease status and following trends. Averaged parameters derived from automated respiratory cycles are more precise and could be displayed by ventilators to improve real-time fine tuning of ventilator settings.

Which physical and social environmental factors are most important for adolescents' cycling for transport? An experimental study using manipulated photographs.

PubMed

Verhoeven, Hannah; Ghekiere, Ariane; Van Cauwenberg, Jelle; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Clarys, Peter; Deforche, Benedicte

2017-08-17

Ecological models emphasize that cycling for transport is determined by an interplay between individual, physical and social environmental factors. The current study investigated (a) which physical and social environmental factors determine adolescents' preferences towards cycling for transport and (b) which individual, physical and social environmental factors are associated with their intention to actually cycle for transport. An online questionnaire consisting of questions on individual and social environmental variables, and 15 choice-based conjoint tasks with manipulated photographs was completed by 882 adolescents (55.3% male; 13.9 ± 1.6 years). Within the choice tasks, participants were asked to indicate which of two situations they would prefer to cycle to a friend's house. The manipulated photographs were all modified versions of one semi-urban street which differed in the following physical micro-environmental attributes (separation of cycle path, evenness of cycle path, speed limit, speed bump, traffic density, amount of vegetation and maintenance). In addition, each photograph was accompanied by two sentences which described varying cycling distances and co-participation in cycling (i.e. cycling alone or with a friend). After each choice task participants were also asked if they would actually cycle in that situation in real life (i.e. intention). Hierarchical Bayes analyses were performed to calculate relative importances and part-worth utilities of environmental attributes. Logistic regression analyses were performed to investigate which individual, physical and social environmental factors were associated with adolescents' intention to actually cycle for transport. Adolescents' preference to cycle for transport was predominantly determined by separation of cycle path, followed by shorter cycling distance and co-participation in cycling. Higher preferences were observed for a separation between the cycle path and motorized traffic by means of a hedge versus a curb, versus a marked line. Similar findings were observed for intention to cycle. Furthermore, evenness of the cycle path and general maintenance of the street were also of considerable importance among adolescents, but to a lesser extent. Results of this experimental study justify investment by local governments in well-separated cycling infrastructure, which seemed to be more important than cycling distance and the social environment.

Pseudo-simple heteroclinic cycles in R4

NASA Astrophysics Data System (ADS)

Chossat, Pascal; Lohse, Alexander; Podvigina, Olga

2018-06-01

We study pseudo-simple heteroclinic cycles for a Γ-equivariant system in R4 with finite Γ ⊂ O(4) , and their nearby dynamics. In particular, in a first step towards a full classification - analogous to that which exists already for the class of simple cycles - we identify all finite subgroups of O(4) admitting pseudo-simple cycles. To this end we introduce a constructive method to build equivariant dynamical systems possessing a robust heteroclinic cycle. Extending a previous study we also investigate the existence of periodic orbits close to a pseudo-simple cycle, which depends on the symmetry groups of equilibria in the cycle. Moreover, we identify subgroups Γ ⊂ O(4) , Γ ⊄ SO(4) , admitting fragmentarily asymptotically stable pseudo-simple heteroclinic cycles. (It has been previously shown that for Γ ⊂ SO(4) pseudo-simple cycles generically are completely unstable.) Finally, we study a generalized heteroclinic cycle, which involves a pseudo-simple cycle as a subset.

Using the Modified Precursor Method to Estimate the Size of Cycle 24

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2008-01-01

Modified geomagnetic precursor techniques for predicting the size of the following sunspot cycle are developed, where these techniques use the 12-month moving averages of the number of disturbed days (when Ap greater than or equals 25), the Ap index, the aa index, and the aaI index at about 4 yr during the declining portion of the preceding sunspot cycle. For cycle 24, these techniques suggest that its RM will measure about 130 +/- 14, a value outside the consensus prediction interval of the low prediction (90 +/- 10) given by the NOAA Solar Cycle 24 Prediction Panel. Furthermore, cycle 24 is predicted to be a fast-rising cycle (ASC = 44 +/- 5 months), peaking before April 2012, presuming the official start of cycle 24 in March 2008. Also discussed are the variation of solar cycle lengths and Hale cycle effects, as related to cycles 23 and 24.

Detonation Jet Engine. Part 1--Thermodynamic Cycle

ERIC Educational Resources Information Center

Bulat, Pavel V.; Volkov, Konstantin N.

2016-01-01

We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid) Green Composites during Thermal Cycling

PubMed Central

Katogi, Hideaki; Takemura, Kenichi; Akiyama, Motoki

2016-01-01

This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid) (PLA) during thermal cycling. Temperature ranges of thermal cycling tests were 35–45 °C and 35–55 °C. The maximum number of cycles was 103 cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35–45 °C, tensile strength of composite at 103 cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35–55 °C, tensile strength and Young’s modulus of composite at 103 cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 103 cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin. PMID:28773694

COMPARISON OF THERMAL EFFICIENCIES FOR A MERCURY-STEAM BINARY VAPOR CYCLE AND THE RANKINE CYCLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prem, L.L.

1961-05-19

A comparison of the thermal efficiencies of the mercurysteam binary vapor cycle and the Rankine cycle shows that the binary cycle efficiency is greater. A temperatureentropy diagram and a schematic layout of the binary cycle are presented for clarity. (N.W.R.)

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Cycle-validation criteria for operation over specified duty cycles. 1065.514 Section 1065.514 Protection of Environment ENVIRONMENTAL... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Cycle-validation criteria for... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...-validation criteria. You must compare the original reference duty cycle points generated as described in...

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Cycle-validation criteria for... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...-validation criteria. You must compare the original reference duty cycle points generated as described in...

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Cycle-validation criteria for... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...-validation criteria. You must compare the original reference duty cycle points generated as described in...

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Cycle-validation criteria for... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...-validation criteria. You must compare the original reference duty cycle points generated as described in...

Sunspot Activity Near Cycle Minimum and What it Might Suggest for Cycle 24, the Next Sunspot Cycle

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2009-01-01

In late 2008, 12-month moving averages of sunspot number, number of spotless days, number of groups, area of sunspots, and area per group were reflective of sunspot cycle minimum conditions for cycle 24, these values being of or near record value. The first spotless day occurred in January 2004 and the first new-cycle, high-latitude spot was reported in January 2008, although old-cycle, low-latitude spots have continued to be seen through April 2009, yielding an overlap of old and new cycle spots of at least 16 mo. New-cycle spots first became dominant over old-cycle spots in September 2008. The minimum value of the weighted mean latitude of sunspots occurred in May 2007, measuring 6.6 deg, and the minimum value of the highest-latitude spot followed in June 2007, measuring 11.7 deg. A cycle length of at least 150 mo is inferred for cycle 23, making it the longest cycle of the modern era. Based on both the maximum-minimum and amplitude-period relationships, cycle 24 is expected to be only of average to below-average size, peaking probably in late 2012 to early 2013, unless it proves to be a statistical outlier.

Prediction of solar activity from solar background magnetic field variations in cycles 21-23

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V., E-mail: s.j.shepherd@brad.ac.uk, E-mail: s.zharkov@hull.ac.uk, E-mail: valentina.zharkova@northumbria.ac.uk

2014-11-01

A comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e.g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in differentmore » layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26.« less

Understanding bicycling in cities using system dynamics modelling.

PubMed

Macmillan, Alexandra; Woodcock, James

2017-12-01

Increasing urban bicycling has established net benefits for human and environmental health. Questions remain about which policies are needed and in what order, to achieve an increase in cycling while avoiding negative consequences. Novel ways of considering cycling policy are needed, bringing together expertise across policy, community and research to develop a shared understanding of the dynamically complex cycling system. In this paper we use a collaborative learning process to develop a dynamic causal model of urban cycling to develop consensus about the nature and order of policies needed in different cycling contexts to optimise outcomes. We used participatory system dynamics modelling to develop causal loop diagrams (CLDs) of cycling in three contrasting contexts: Auckland, London and Nijmegen. We combined qualitative interviews and workshops to develop the CLDs. We used the three CLDs to compare and contrast influences on cycling at different points on a "cycling trajectory" and drew out policy insights. The three CLDs consisted of feedback loops dynamically influencing cycling, with significant overlap between the three diagrams. Common reinforcing patterns emerged: growing numbers of people cycling lifts political will to improve the environment; cycling safety in numbers drives further growth; and more cycling can lead to normalisation across the population. By contrast, limits to growth varied as cycling increases. In Auckland and London, real and perceived danger was considered the main limit, with added barriers to normalisation in London. Cycling congestion and "market saturation" were important in the Netherlands. A generalisable, dynamic causal theory for urban cycling enables a more ordered set of policy recommendations for different cities on a cycling trajectory. Participation meant the collective knowledge of cycling stakeholders was represented and triangulated with research evidence. Extending this research to further cities, especially in low-middle income countries, would enhance generalizability of the CLDs.

Anticipating Cycle 24 Minimum and Its Consequences

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2007-01-01

On the basis of the 12-mo moving average of monthly mean sunspot number (R) through November 2006, cycle 23 has persisted for 126 mo, having had a minimum of 8.0 in May 1996, a peak of 120.8 in April 2000, and an ascent duration of 47 mo. In November 2006, the 12-mo moving average of monthly mean sunspot number was 12.7, a value just outside the upper observed envelope of sunspot minimum values for the most recent cycles 16-23 (range 3.4-12.3), but within the 90-percent prediction interval (7.8 +/- 6.7). The first spotless day during the decline of cycle 23 occurred in January 2004, and the first occurrence of 10 or more and 20 or more spotless days was February 2006 and April 2007, respectively, inferring that sunspot minimum for cycle 24 is imminent. Through May 2007, 121 spotless days have accumulated. In terms of the weighted mean latitude (weighed by spot area) (LAT) and the highest observed latitude spot (HLS) in November 2006, 12-mo moving averages of these parameters measured 7.9 and 14.6 deg, respectively, these values being the lowest values yet observed during the decline of cycle 23 and being below corresponding mean values found for cycles 16-23. As yet, no high-latitude new-cycle spots have been seen nor has there been an upturn in LAT and HLS, these conditions having always preceded new cycle minimum by several months for past cycles. Together, these findings suggest that cycle 24 s minimum amplitude still lies well beyond November 2006. This implies that cycle 23 s period either will lie in the period "gap" (127-134 mo), a first for a sunspot cycle, or it will be longer than 134 mo, thus making cycle 23 a long-period cycle (like cycle 20) and indicating that cycle 24 s minimum will occur after July 2007. Should cycle 23 prove to be a cycle of longer period, a consequence might be that the maximum amplitude for cycle 24 may be smaller than previously predicted.

Not all counterclockwise thermodynamic cycles are refrigerators

NASA Astrophysics Data System (ADS)

Dickerson, R. H.; Mottmann, J.

2016-06-01

Clockwise cycles on PV diagrams always represent heat engines. It is therefore tempting to assume that counterclockwise cycles always represent refrigerators. This common assumption is incorrect: most counterclockwise cycles cannot be refrigerators. This surprising result is explored here for quasi-static ideal gas cycles, and the necessary conditions for refrigeration cycles are clarified. Three logically self-consistent criteria can be used to determine if a counterclockwise cycle is a refrigerator. The most fundamental test compares the counterclockwise cycle with a correctly determined corresponding Carnot cycle. Other criteria we employ include a widely accepted description of the functional behavior of refrigerators, and a corollary to the second law that limits a refrigerator's coefficient of performance.

Triple-effect absorption chiller cycle: A step beyond double-effect cycles

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeVault, R.C.

1990-01-01

Many advanced'' absorption cycles have been proposed during the current century. Of the hundreds of absorption cycles which have been patented throughout the world, all commercially manufactured products for air conditioning buildings have been variations of just two basic absorption cycles: single-effect and condenser-coupled double-effect cycles. The relatively low cooling coefficients of performance (COPs) inherent in single-effect and double-effect cycles limits the economic applicability of absorption air conditioners (chillers) in the United States. A triple-effect absorption chiller cycle is discussed. This cycle uses two condensers and two absorbers to achieve the triple effect.'' Depending on the absorption fluids selected, thismore » triple-effect cycle is predicted to improve cooling COPs by 18% to 60% compared with the equivalent double-effect cycle. This performance improvement is obtained without increasing the total amount of heat-transfer surface area needed for the heat exchangers. A comparison between the calculated performances of a double-effect cycle and a triple-effect cycle (both using ammonia-water (NH{sub 3}/H{sub 2}O) as the absorption fluid pair) is presented. The triple-effect cycle is predicted to have an 18% higher cooling COP (1.41 compared with 1.2 for a double-effect), lower pressure (47.70 atm (701 psi) instead of 68.05 atm (1000 psi)), significantly reduced pumping power (less than one-half that of the double-effect cycle), and potentially lower construction cost (33% less total heat exchange needed). Practical implications for this triple-effect cycle are discussed. 16 refs., 5 figs., 1 tab.« less

Can cycling safety be improved by opening all unidirectional cycle paths for cycle traffic in both directions? A theoretical examination of available literature and data.

PubMed

Methorst, Rob; Schepers, Paul; Kamminga, Jaap; Zeegers, Theo; Fishman, Elliot

2017-08-01

Many studies have found bicycle-motor vehicle crashes to be more likely on bidirectional cycle paths than on unidirectional cycle paths because drivers do not expect cyclists riding at the right side of the road. In this paper we discuss the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions prevent this lack of expectancy and accordingly improves cycling safety. A new national standard requires careful consideration because a reversal is difficult once cyclists are used to their new freedom of route choice. We therefore explored the hypothesis using available data, research, and theories. The results show that of the length of cycle paths along distributor roads in the Netherlands, 72% is bidirectional. If drivers would become used to cyclists riding at the left side of the road, this result raises the question of why bidirectional cycle paths in the Netherlands still have a poor safety record compared to unidirectional cycle paths. Moreover, our exploration suggested that bidirectional cycle paths have additional safety problems. It increases the complexity of unsignalized intersections because drivers have to scan more directions in a short period of time. Moreover, there are some indications that the likelihood of frontal crashes between cyclists increases. We reject the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions will improve cycle safety. We recommend more attention for mitigating measures given the widespread application of bidirectional cycle paths in the Netherlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reversible and irreversible heat engine and refrigerator cycles

NASA Astrophysics Data System (ADS)

Leff, Harvey S.

2018-05-01

Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

Prognostic factors for patients undergoing vitrified-warmed human embryo transfer cycles: a retrospective cohort study.

PubMed

Takahashi, Toshifumi; Hasegawa, Ayumi; Igarashi, Hideki; Amita, Mitsuyoshi; Matsukawa, Jun; Takehara, Isao; Suzuki, Satoko; Nagase, Satoru

2017-06-01

We examined the prognostic factors for pregnancy in 210 vitrified-warmed embryo transfer (ET) cycles in 121 patients. The univariate analysis showed that age, gravida, the number of cycles associated with infertility caused by endometriosis, the number of previous assisted reproductive technology (ART) treatment cycles, and the number of ICSI procedures were significantly lower in pregnant cycles compared with non-pregnant cycles. The percentages of ET using at least one intact embryo and of ET using at least one embryo that had developed further after warming were significantly higher in pregnant cycles compared with non-pregnant cycles. Multivariate logistic regression analysis showed that previous ART treatment cycles, ET with at least one intact embryo, and ET using at least one embryo that had developed further were independent prognostic factors for pregnancy in vitrified-warmed ET cycles. We conclude that fewer previous ART treatment cycles, ET using at least one intact embryo, and ET with embryos that have developed further after warming might be favourable prognostic factors for pregnancy in vitrified-warmed ET cycles.

Bipolar mood cycles and lunar tidal cycles

PubMed Central

Wehr, T A

2018-01-01

In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon’s semi-diurnal gravimetric tides: the 14.8-day spring–neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies (‘supermoons’). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles’ being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon’s semi-diurnal gravimetric tides might have driven the patients’ bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker’s phase-relationship to sleep in a manner that is known to cause switches from depression to mania. PMID:28115741

Design of high-efficiency Joule-Thomson cycles for high-temperature superconductor power cable cooling

NASA Astrophysics Data System (ADS)

Jin, Lingxue; Lee, Cheonkyu; Baek, Seungwhan; Jeong, Sangkwon

2018-07-01

Liquid nitrogen (LN2) is commonly used as the coolant of a high temperature superconductor (HTS) power cable. The LN2 is continuously cooled by a subcooler to maintain an appropriate operating temperature of the cable. This paper proposes two Joule-Thomson (JT) refrigeration cycles for subcooling the LN2 coolant by using nitrogen itself as the working fluid. Additionally, an innovative HTS cooling cycle, of which the cable coolant and the refrigerant are unified and supplied from the same source, is suggested and analyzed in detail. Among these cycles, the highest COP is obtained in the JT cycle with a vacuum pump (Cycle A) which is 0.115 at 78 K, and the Carnot efficiency is 32.8%. The integrated HTS cooling cycle (Cycle C) can reach the maximum COP of 0.087, and the Carnot efficiency of 24.8%. Although Cycle C has a relatively low cycle efficiency when compared to that of the separated refrigeration cycle, it can be a good alternative in engineering applications, because the assembled hardware has few machinery components in a more compact configuration than the other cycles.

A factor analysis approach to examining relationships among ovarian steroid concentrations, gonadotrophin concentrations and menstrual cycle length characteristics in healthy, cycling women

PubMed Central

Barrett, E.S.; Thune, I.; Lipson, S.F.; Furberg, A.-S.; Ellison, P.T.

2013-01-01

STUDY QUESTION How are ovarian steroid concentrations, gonadotrophins and menstrual cycle characteristics inter-related within normal menstrual cycles? SUMMARY ANSWER Within cycles, measures of estradiol production are highly related to one another, as are measures of progesterone production; however, the two hormones also show some independence from one another, and measures of cycle length and gonadotrophin concentrations show even greater independence, indicating minimal integration within cycles. WHAT IS KNOWN ALREADY The menstrual cycle is typically conceptualized as a cohesive unit, with hormone levels, follicular development and ovulation all closely inter-related within a single cycle. Empirical support for this idea is limited, however, and to our knowledge, no analysis has examined the relationships among all of these components simultaneously. STUDY DESIGN, SIZE, DURATION A total of 206 healthy, cycling Norwegian women participated in a prospective cohort study (EBBA-I) over the duration of a single menstrual cycle. Of these, 192 contributed hormonal and cycle data to the current analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS Subjects provided daily saliva samples throughout the menstrual cycle from which estradiol and progesterone concentrations were measured. FSH and LH concentrations were measured in serum samples from three points in the same menstrual cycle and cycle length characteristics were calculated based on hormonal data and menstrual records. A factor analysis was conducted to examine the underlying relationships among 22 variables derived from the hormonal data and menstrual cycle characteristics. MAIN RESULTS AND THE ROLE OF CHANCE Six rotated factors emerged, explaining 80% of the variance in the data. Of these, factors representing estradiol and progesterone concentrations accounted for 37 and 13% of the variance, respectively. There was some association between measures of estradiol and progesterone production within cycles; however, cycle length characteristics and gonadotrophin concentrations showed little association with any measure of ovarian hormone concentrations. LIMITATIONS, REASONS FOR CAUTION Our summary measures of ovarian hormones may be imprecise in women with extremely long or short cycles, which could affect the patterns emerging in the factor analysis. Given that we only had data from one cycle on each woman, we cannot address how cycle characteristics may covary within individual women across multiple cycles. WIDER IMPLICATIONS OF THE FINDINGS Our findings are generalizable to other healthy populations with typical cycles, however, may not be applicable to cycles that are anovulatory, extreme in length or otherwise atypical. The results support previous findings that measures of estradiol production are highly correlated across the cycle, as are measures of progesterone production. Estradiol and progesterone concentrations are associated with one another, furthermore. However factor analysis also revealed more complex underlying patterns in the menstrual cycle, highlighting the fact that gonadotrophin concentrations and cycle length characteristics are virtually independent of ovarian hormones. These results suggest that despite integration of follicular and luteal ovarian steroid production across the cycle, cycle quality is a multi-faceted construct, rather than a single dimension. STUDY FUNDING/COMPETING INTEREST(S) The EBBA-I study was supported by a grant from the Norwegian Cancer Society (49 258, 05087); Foundation for the Norwegian Health and Rehabilitation Organizations (59010-2000/2001/2002); Aakre Foundation (5695-2000, 5754-2002) and Health Region East. The current analyses were completed under funding from the National Institutes of Health (K12 ES019852). No competing interests declared. PMID:23250924

Your Menstrual Cycle

MedlinePlus

... your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... that take place over the weeks in your cycle. Want to know what happens on each day ...

Predicting the Size and Timing of Sunspot Maximum for Cycle 24

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2010-01-01

For cycle 24, the minimum value of the 12-month moving average (12-mma) of the AA-geomagnetic index in the vicinity of sunspot minimum (AAm) appears to have occurred in September 2009, measuring about 8.4 nT and following sunspot minimum by 9 months. This is the lowest value of AAm ever recorded, falling below that of 8.9 nT, previously attributed to cycle 14, which also is the smallest maximum amplitude (RM) cycle of the modern era (RM = 64.2). Based on the method of Ohl (the preferential association between RM and AAm for an ongoing cycle), one expects cycle 24 to have RM = 55+/-17 (the +/-1 - sigma prediction interval). Instead, using a variation of Ohl's method, one based on using 2-cycle moving averages (2-cma), one expects cycle 23's 2-cma of RM to be about 115.5+/-8.7 (the +/-1 - sigma prediction interval), inferring an RM of about 62+/-35 for cycle 24. Hence, it seems clear that cycle 24 will be smaller in size than was seen in cycle 23 (RM = 120.8) and, likely, will be comparable in size to that of cycle 14. From the Waldmeier effect (the preferential association between the ascent duration (ASC) and RM for an ongoing cycle), one expects cycle 24 to be a slow-rising cycle (ASC > or equal to 48 months), having RM occurrence after December 2012, unless it turns out to be a statistical outlier.

Impact of offering cycle training in schools upon cycling behaviour: a natural experimental study.

PubMed

Goodman, Anna; van Sluijs, Esther M F; Ogilvie, David

2016-03-08

England's national cycle training scheme, 'Bikeability', aims to give children in England the confidence to cycle more. There is, however, little evidence on the effectiveness of cycle training in achieving this. We therefore examined whether delivering Bikeability was associated with cycling frequency or with independent cycling. We conducted a natural experimental study using information on children aged 10-11 years participating in the nationally-representative Millennium Cohort Study. We identified Cohort participants whose schools had offered Bikeability in 2011-2012 using operational Bikeability delivery data (children in London excluded, as delivery data not available). Our natural experimental design capitalised on the fact that Cohort participants were surveyed at different times during 2012 and were also offered Bikeability at different times during 2012. This allowed us to compare cycling levels between children whose schools delivered Bikeability before their survey interview ('intervention group', N = 2563) and an otherwise comparable group of children whose schools delivered Bikeability later in the year ('control group', N = 773). Parents reported whether their child had completed formal cycle training; their child's cycling frequency; whether their child ever made local cycling trips without an adult; and other child and family factors. We used Poisson regression with robust standard errors to examine whether cycling behaviour differed between the intervention and control groups. Children whose school had offered Bikeability were much more likely to have completed cycle training than the control group (68% vs. 28%, p < 0.001). There was, however, no evidence that delivering Bikeability in school was associated with cycling more often (49.0% cycling at least once per week in the intervention group vs. 49.6% in the control group; adjusted risk ratio 0.99, 95% CI 0.89, 1.10). There was likewise no evidence of an association with cycling independently (51.5% in the intervention group vs. 50.1% in the control group; adjusted risk ratio 0.97, 95% CI 0.89, 1.06). Offering high-quality cycle training free at the point of delivery in English schools encourages children to do cycle training, but we found no evidence of short-term effects on cycling frequency or independent cycling. Future evaluation should investigate longer-term effects on these and other stated Bikeability objectives such as increasing cycling safety.

The Solar Cycle.

PubMed

Hathaway, David H

The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev-Ohl (even-odd) Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24. Supplementary material is available for this article at 10.1007/lrsp-2015-4.

The effect of ultradian and orbital cycles on plant growth

NASA Technical Reports Server (NTRS)

Berry, W.; Hoshizaki, T.; Ulrich, A.

1986-01-01

In a series of experiments using sugar beets, researchers investigated the effects of varying cycles lengths on growth (0.37 hr to 48 hr). Each cycle was equally divided into a light and dark period so that each treatment regardless of cycle length received the same amount of light over the 17 weeks of the experiment. Two growth parameters were used to evaluate the effects of cycle length, total fresh weight and sucrose content of the storage root. Both parameters showed very similar responses in that under long cycles (12 hr or greater) growth was normal, whereas plants growing under shorter cycle periods were progressively inhibited. Minimum growth occurred at a cycle period of 0.75 hr. The yield at the 0.75 hr cycle, where was at a minimum, for total fresh weight was only 51 percent compared to the 24 hr cycle. The yield of sucrose was even more reduced at 41 percent of the 24 hr cycle.

On the level of skill in predicting maximum sunspot number - A comparative study of single variate and bivariate precursor techniques

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1990-01-01

The level of skill in predicting the size of the sunspot cycle is investigated for the two types of precursor techniques, single variate and bivariate fits, both applied to cycle 22. The present level of growth in solar activity is compared to the mean level of growth (cycles 10-21) and to the predictions based on the precursor techniques. It is shown that, for cycle 22, both single variate methods (based on geomagnetic data) and bivariate methods suggest a maximum amplitude smaller than that observed for cycle 19, and possibly for cycle 21. Compared to the mean cycle, cycle 22 is presently behaving as if it were a +2.6 sigma cycle (maximum amplitude of about 225), which means that either it will be the first cycle not to be reliably predicted by the combined precursor techniques or its deviation relative to the mean cycle will substantially decrease over the next 18 months.

Evaluation of Cycle Life and Characterization of YTP 45 Ah Li-Ion Battery for EMU

NASA Technical Reports Server (NTRS)

Deng, Yi; Jeevarajan, Judith; Rehm, Raymond; Bragg, Bobby; Strangways, Brad

2002-01-01

Li-ion batteries, with longer cycle life and higher energy density features, are now more and more attractive and applied in multiple fields. The YTP 45 Ah Li-ion battery has been evaluated here and may be employed in EMU in the future. Evaluations were on: (1) Cycle life tests - 500 cycles total (completed 40 cycles in simulated shuttle use mode and 460 cycles in an accelerated use mode, and recorded differential voltage of individual cell in battery); (2) Characterization test - discharge capacity measurement in environment temperature of -10, 25, 50 C before and after 500 cycles; and (3) Thermal testing - charge and discharge at 50 C and -10 C before and after 500 cycles. The battery showed less than a 9% drop of initial discharge capacity and energy within 500 cycles with 475 cycles 59% DOD plus 25 cycles 100% DOD. The EOD voltage ranged from 16.0 to 18.0 V, which fits the requirement for operating the EMU.

Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy.

PubMed

Wu, Feng-Hua; Mu, Lei; Li, Xiao-Lan; Hu, Yi-Bing; Liu, Hui; Han, Lin-Tao; Gong, Jian-Ping

2017-10-03

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo . Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo . Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro . Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy

PubMed Central

Wu, Feng-Hua; Mu, Lei; Li, Xiao-Lan; Hu, Yi-Bing; Liu, Hui; Han, Lin-Tao; Gong, Jian-Ping

2017-01-01

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo. Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo. Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro. Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence. PMID:29108242

On the Period-Amplitude and Amplitude-Period Relationships

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2008-01-01

Examined are Period-Amplitude and Amplitude-Period relationships based on the cyclic behavior of the 12-month moving averages of monthly mean sunspot numbers for cycles 0.23, both in terms of Fisher's exact tests for 2x2 contingency tables and linear regression analyses. Concerning the Period-Amplitude relationship (same cycle), because cycle 23's maximum amplitude is known to be 120.8, the inferred regressions (90-percent prediction intervals) suggest that its period will be 131 +/- 24 months (using all cycles) or 131 +/- 18 months (ignoring cycles 2 and 4, which have the extremes of period, 108 and 164 months, respectively). Because cycle 23 has already persisted for 142 months (May 1996 through February 2008), based on the latter prediction, it should end before September 2008. Concerning the Amplitude-Period relationship (following cycle maximum amplitude versus preceding cycle period), because cycle 23's period is known to be at least 142 months, the inferred regressions (90-percent prediction intervals) suggest that cycle 24's maximum amplitude will be about less than or equal to 96.1 +/- 55.0 (using all cycle pairs) or less than or equal to 91.0 +/- 36.7 (ignoring statistical outlier cycle pairs). Hence, cycle 24's maximum amplitude is expected to be less than 151, perhaps even less than 128, unless cycle pair 23/24 proves to be a statistical outlier.

The Cycles of Math and Science.

ERIC Educational Resources Information Center

Sumrall, William J.; Rock, David

2002-01-01

Introduces lesson plans on cycles designed for middle school students. Activities include: (1) "Boiling and Evaporation"; (2) "Experimenting with Evaporation"; (3) "Condensation and the Water Cycle"; and (4) "Understanding Cycles". Explains the mathematical applications of cycles. (YDS)

RIEGER-TYPE PERIODICITY DURING SOLAR CYCLES 14–24: ESTIMATION OF DYNAMO MAGNETIC FIELD STRENGTH IN THE SOLAR INTERIOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil

2016-07-20

Solar activity undergoes a variation over timescales of several months known as Rieger-type periodicity, which usually occurs near maxima of sunspot cycles. An early analysis showed that the periodicity appears only in some cycles and is absent in other cycles. But the appearance/absence during different cycles has not been explained. We performed a wavelet analysis of sunspot data from the Greenwich Royal Observatory and the Royal Observatory of Belgium during cycles 14–24. We found that the Rieger-type periods occur in all cycles, but they are cycle dependent: shorter periods occur during stronger cycles. Our analysis revealed a periodicity of 185–195more » days during the weak cycles 14–15 and 24 and a periodicity of 155–165 days during the stronger cycles 16–23. We derived the dispersion relation of the spherical harmonics of the magnetic Rossby waves in the presence of differential rotation and a toroidal magnetic field in the dynamo layer near the base of the convection zone. This showed that the harmonics of fast Rossby waves with m = 1 and n = 4, where m ( n ) indicates the toroidal (poloidal) wavenumbers, perfectly fit with the observed periodicity. The variation of the toroidal field strength from weaker to stronger cycles may lead to the different periods found in those cycles, which explains the observed enigmatic feature of the Rieger-type periodicity. Finally, we used the observed periodicity to estimate the dynamo field strength during cycles 14–24. Our estimations suggest a field strength of ∼40 kG for the stronger cycles and ∼20 kG for the weaker cycles.« less

Effect of Embryo Banking on U.S. National Assisted Reproductive Technology Live Birth Rates.

PubMed

Kushnir, Vitaly A; Barad, David H; Albertini, David F; Darmon, Sarah K; Gleicher, Norbert

2016-01-01

Assisted Reproductive Technology (ART) reports generated by the Centers for Disease Control and Prevention (CDC) exclude embryo banking cycles from outcome calculations. We examined data reported to the CDC in 2013 for the impact of embryo banking exclusion on national ART outcomes by recalculating autologous oocyte ART live birth rates. Inflation of reported fresh ART cycle live birth rates was assessed for all age groups of infertile women as the difference between fresh cycle live births with reference to number of initiated fresh cycles (excluding embryo banking cycles), as typically reported by the CDC, and fresh cycle live births with reference to total initiated fresh ART cycles (including embryo banking cycles). During 2013, out of 121,351 fresh non-donor ART cycles 27,564 (22.7%) involved embryo banking. The proportion of banking cycles increased with female age from 15.5% in women <35 years to 56.5% in women >44 years. Concomitantly, the proportion of thawed cycles decreased with advancing female age (P <0.0001). Exclusion of embryo banking cycles led to inflation of live birth rates in fresh ART cycles, increasing in size in parallel to advancing female age and utilization of embryo banking, reaching 56.3% in women age >44. The inflation of live birth rates in thawed cycles could not be calculated from the publically available CDC data but appears to be even greater. Utilization of embryo banking increased during 2013 with advancing female age, suggesting a potential age selection bias. Exclusion of embryo banking cycles from national ART outcome reports significantly inflated national ART success rates, especially among older women. Exclusion of embryo banking cycles from US National Assisted Reproductive Technology outcome reports significantly inflates reported success rates especially in older women.

Effect of Embryo Banking on U.S. National Assisted Reproductive Technology Live Birth Rates

PubMed Central

Kushnir, Vitaly A.; Barad, David H.; Albertini, David F.; Darmon, Sarah K.; Gleicher, Norbert

2016-01-01

Background Assisted Reproductive Technology (ART) reports generated by the Centers for Disease Control and Prevention (CDC) exclude embryo banking cycles from outcome calculations. Methods We examined data reported to the CDC in 2013 for the impact of embryo banking exclusion on national ART outcomes by recalculating autologous oocyte ART live birth rates. Inflation of reported fresh ART cycle live birth rates was assessed for all age groups of infertile women as the difference between fresh cycle live births with reference to number of initiated fresh cycles (excluding embryo banking cycles), as typically reported by the CDC, and fresh cycle live births with reference to total initiated fresh ART cycles (including embryo banking cycles). Results During 2013, out of 121,351 fresh non-donor ART cycles 27,564 (22.7%) involved embryo banking. The proportion of banking cycles increased with female age from 15.5% in women <35 years to 56.5% in women >44 years. Concomitantly, the proportion of thawed cycles decreased with advancing female age (P <0.0001). Exclusion of embryo banking cycles led to inflation of live birth rates in fresh ART cycles, increasing in size in parallel to advancing female age and utilization of embryo banking, reaching 56.3% in women age >44. The inflation of live birth rates in thawed cycles could not be calculated from the publically available CDC data but appears to be even greater. Conclusions Utilization of embryo banking increased during 2013 with advancing female age, suggesting a potential age selection bias. Exclusion of embryo banking cycles from national ART outcome reports significantly inflated national ART success rates, especially among older women. Précis Exclusion of embryo banking cycles from US National Assisted Reproductive Technology outcome reports significantly inflates reported success rates especially in older women. PMID:27159215

Health impact assessment of cycling network expansions in European cities.

PubMed

Mueller, Natalie; Rojas-Rueda, David; Salmon, Maëlle; Martinez, David; Ambros, Albert; Brand, Christian; de Nazelle, Audrey; Dons, Evi; Gaupp-Berghausen, Mailin; Gerike, Regine; Götschi, Thomas; Iacorossi, Francesco; Int Panis, Luc; Kahlmeier, Sonja; Raser, Elisabeth; Nieuwenhuijsen, Mark

2018-04-01

We conducted a health impact assessment (HIA) of cycling network expansions in seven European cities. We modeled the association between cycling network length and cycling mode share and estimated health impacts of the expansion of cycling networks. First, we performed a non-linear least square regression to assess the relationship between cycling network length and cycling mode share for 167 European cities. Second, we conducted a quantitative HIA for the seven cities of different scenarios (S) assessing how an expansion of the cycling network [i.e. 10% (S1); 50% (S2); 100% (S3), and all-streets (S4)] would lead to an increase in cycling mode share and estimated mortality impacts thereof. We quantified mortality impacts for changes in physical activity, air pollution and traffic incidents. Third, we conducted a cost-benefit analysis. The cycling network length was associated with a cycling mode share of up to 24.7% in European cities. The all-streets scenario (S4) produced greatest benefits through increases in cycling for London with 1,210 premature deaths (95% CI: 447-1,972) avoidable annually, followed by Rome (433; 95% CI: 170-695), Barcelona (248; 95% CI: 86-410), Vienna (146; 95% CI: 40-252), Zurich (58; 95% CI: 16-100) and Antwerp (7; 95% CI: 3-11). The largest cost-benefit ratios were found for the 10% increase in cycling networks (S1). If all 167 European cities achieved a cycling mode share of 24.7% over 10,000 premature deaths could be avoided annually. In European cities, expansions of cycling networks were associated with increases in cycling and estimated to provide health and economic benefits. Copyright © 2018 Elsevier Inc. All rights reserved.

Cardiopulmonary resuscitation duty cycle in out-of-hospital cardiac arrest.

PubMed

Johnson, Bryce V; Johnson, Bryce; Coult, Jason; Fahrenbruch, Carol; Blackwood, Jennifer; Sherman, Larry; Kudenchuk, Peter; Sayre, Michael; Rea, Thomas

2015-02-01

Duty cycle is the portion of time spent in compression relative to total time of the compression-decompression cycle. Guidelines recommend a 50% duty cycle based largely on animal investigation. We undertook a descriptive evaluation of duty cycle in human resuscitation, and whether duty cycle correlates with other CPR measures. We calculated the duty cycle, compression depth, and compression rate during EMS resuscitation of 164 patients with out-of-hospital ventricular fibrillation cardiac arrest. We captured force recordings from a chest accelerometer to measure ten-second CPR epochs that preceded rhythm analysis. Duty cycle was calculated using two methods. Effective compression time (ECT) is the time from beginning to end of compression divided by total period for that compression-decompression cycle. Area duty cycle (ADC) is the ratio of area under the force curve divided by total area of one compression-decompression cycle. We evaluated the compression depth and compression rate according to duty cycle quartiles. There were 369 ten-second epochs among 164 patients. The median duty cycle was 38.8% (SD=5.5%) using ECT and 32.2% (SD=4.3%) using ADC. A relatively shorter compression phase (lower duty cycle) was associated with greater compression depth (test for trend <0.05 for ECT and ADC) and slower compression rate (test for trend <0.05 for ADC). Sixty-one of 164 patients (37%) survived to hospital discharge. Duty cycle was below the 50% recommended guideline, and was associated with compression depth and rate. These findings provider rationale to incorporate duty cycle into research aimed at understanding optimal CPR metrics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Reproductive cycles in tropical intertidal gastropods are timed around tidal amplitude cycles.

PubMed

Collin, Rachel; Kerr, Kecia; Contolini, Gina; Ochoa, Isis

2017-08-01

Reproduction in iteroparous marine organisms is often timed with abiotic cycles and may follow lunar, tidal amplitude, or daily cycles. Among intertidal marine invertebrates, decapods are well known to time larval release to coincide with large amplitude nighttime tides, which minimizes the risk of predation. Such bimonthly cycles have been reported for few other intertidal invertebrates. We documented the reproduction of 6 gastropod species from Panama to determine whether they demonstrate reproductive cycles, whether these cycles follow a 2-week cycle, and whether cycles are timed so that larval release occurs during large amplitude tides. Two of the species ( Crepidula cf. marginalis and Nerita scabricosta ) showed nonuniform reproduction, but without clear peaks in timing relative to tidal or lunar cycles. The other 4 species show clear peaks in reproduction occurring every 2 weeks. In 3 of these species ( Cerithideopsis carlifornica var. valida, Littoraria variegata , and Natica chemnitzi ), hatching occurred within 4 days of the maximum amplitude tides. Siphonaria palmata exhibit strong cycles, but reproduction occurred during the neap tides. Strong differences in the intensity of reproduction of Cerithideopsis carlifornica , and in particular, Littoraria variegata , between the larger and smaller spring tides of a lunar month indicate that these species time reproduction with the tidal amplitude cycle rather than the lunar cycle. For those species that reproduce during both the wet and dry seasons, we found that reproductive timing did not differ between seasons despite strong differences in temperature and precipitation. Overall, we found that most (4/6) species have strong reproductive cycles synchronized with the tidal amplitude cycle and that seasonal differences in abiotic factors do not alter these cycles.

Analysis of Perioperative Chemotherapy in Resected Pancreatic Cancer: Identifying the Number and Sequence of Chemotherapy Cycles Needed to Optimize Survival.

PubMed

Epelboym, Irene; Zenati, Mazen S; Hamad, Ahmad; Steve, Jennifer; Lee, Kenneth K; Bahary, Nathan; Hogg, Melissa E; Zeh, Herbert J; Zureikat, Amer H

2017-09-01

Receipt of 6 cycles of adjuvant chemotherapy (AC) is standard of care in pancreatic cancer (PC). Neoadjuvant chemotherapy (NAC) is increasingly utilized; however, optimal number of cycles needed alone or in combination with AC remains unknown. We sought to determine the optimal number and sequence of perioperative chemotherapy cycles in PC. Single institutional review of all resected PCs from 2008 to 2015. The impact of cumulative number of chemotherapy cycles received (0, 1-5, and ≥6 cycles) and their sequence (NAC, AC, or NAC + AC) on overall survival was evaluated Cox-proportional hazard modeling, using 6 cycles of AC as reference. A total of 522 patients were analyzed. Based on sample size distribution, four combinations were evaluated: 0 cycles = 12.1%, 1-5 cycles of combined NAC + AC = 29%, 6 cycles of AC = 25%, and ≥6 cycles of combined NAC + AC = 34%, with corresponding survival. 13.1, 18.5, 37, and 36.8 months. On MVA (P < 0.0001), tumor stage [hazard ratio (HR) 1.35], LNR (HR 4.3), and R1 margins (HR 1.77) were associated with increased hazard of death. Compared with 6 cycles AC, receipt of 0 cycles [HR 3.57, confidence interval (CI) 2.47-5.18] or 1-5 cycles in any combination (HR 2.37, CI 1.73-3.23) was associated with increased hazard of death, whereas receipt of ≥6 cycles in any sequence was associated with optimal and comparable survival (HR 1.07, CI 0.78-1.47). Receipt of 6 or more perioperative cycles of chemotherapy either as combined neoadjuvant and adjuvant or adjuvant alone may be associated with optimal and comparable survival in resected PC.

Evolution and regulation of complex life cycles: a brown algal perspective.

PubMed

Cock, J Mark; Godfroy, Olivier; Macaisne, Nicolas; Peters, Akira F; Coelho, Susana M

2014-02-01

The life cycle of an organism is one of its fundamental features, influencing many aspects of its biology. The brown algae exhibit a diverse range of life cycles indicating that transitions between life cycle types may have been key adaptive events in the evolution of this group. Life cycle mutants, identified in the model organism Ectocarpus, are providing information about how life cycle progression is regulated at the molecular level in brown algae. We explore some of the implications of the phenotypes of the life cycle mutants described to date and draw comparisons with recent insights into life cycle regulation in the green lineage. Given the importance of coordinating growth and development with life cycle progression, we suggest that the co-option of ancient life cycle regulators to control key developmental events may be a common feature in diverse groups of multicellular eukaryotes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of creep damage on the low cycle thermal-mechanical fatigue behavior of two tantalum base alloys

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Doble, G. S.

1972-01-01

Low cycle fatigue tests have been performed on the tantalum base alloys T-111 and ASTAR 811C with synchronized, independently programmed temperature and strain cycling. The thermal-mechanical cycles applied fell into three basic categories: these were isothermal cycling, in-phase thermal cycling, and out-of-phase thermal cycling. In-phase cycling was defined as tensile deformation associated with high temperature and compressive deformation with low temperature, while out-of-phase thermal cycling was defined as the reverse case. The in-phase thermal cycling had a pronounced detrimental influence on the fatigue life of both alloys, with the life reduction being greater in the solid solution strengthened T-111 alloy than in the carbide strengthened ASTAR 811C alloy. The out-of-phase tests also showed pronounced effects on the fatigue life of both alloys, although not as dramatic.

Evaluation of Coal Gasification/Combined Cycle Power Plant Feasibility at the Sewells Point Naval Complex, Norfolk, Virginia.

DTIC Science & Technology

1981-07-01

2 No. Name Page I 3-2 Rankine Cycle Configuration and Temperature- Entropy Chart 3-6 S 3-3 Brayton Cycle Configuration and Temperature- Entropy Chart...shown in Exhibit 3-1 presents the combined cycle as integrated with the gasification plant, i.e., there is an interchange of electric power, feedwater ...Brayton and Rankine cycles , respectively. The cycle configuration and the temperature-entropy charts for these two cycles are shown in Exhibits 3-2 and 3

Landscape and flux reveal a new global view and physical quantification of mammalian cell cycle

PubMed Central

Li, Chunhe; Wang, Jin

2014-01-01

Cell cycles, essential for biological function, have been investigated extensively. However, enabling a global understanding and defining a physical quantification of the stability and function of the cell cycle remains challenging. Based upon a mammalian cell cycle gene network, we uncovered the underlying Mexican hat landscape of the cell cycle. We found the emergence of three local basins of attraction and two major potential barriers along the cell cycle trajectory. The three local basins of attraction characterize the G1, S/G2, and M phases. The barriers characterize the G1 and S/G2 checkpoints, respectively, of the cell cycle, thus providing an explanation of the checkpoint mechanism for the cell cycle from the physical perspective. We found that the progression of a cell cycle is determined by two driving forces: curl flux for acceleration and potential barriers for deceleration along the cycle path. Therefore, the cell cycle can be promoted (suppressed), either by enhancing (suppressing) the flux (representing the energy input) or by lowering (increasing) the barrier along the cell cycle path. We found that both the entropy production rate and energy per cell cycle increase as the growth factor increases. This reflects that cell growth and division are driven by energy or nutrition supply. More energy input increases flux and decreases barrier along the cell cycle path, leading to faster oscillations. We also identified certain key genes and regulations for stability and progression of the cell cycle. Some of these findings were evidenced from experiments whereas others lead to predictions and potential anticancer strategies. PMID:25228772