scholarly journals DEVELOPMENT OF CARBOXYLATION CAPACITY IN TISSUE-CULTURED STRAWBERRY FOLLOWING TRANSPLANTING.

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 481f-481
Author(s):  
Yves Desjardins ◽  
André Gosselin
Keyword(s):  
De Novo ◽  
Carbon Assimilation ◽  
Carbon Dioxide Concentration ◽  
Total Activity ◽  
Bisphosphate Carboxylase ◽  
Ribulose 1 ◽  
Different Origins ◽  
Photosynthetic Carbon Assimilation ◽  
Negligible Contribution

Strawberry plantlets (Fragaria X ananassa Duch. cv. Kent) were submitted to a factorial arrangement of 2 photosynthetic photon fluxes (PPF) (80 and 150 μmol·m-2·s-1, PAR) and 2 CO2 concentrations (330 and 3000 ppm) during the in vitro rooting stage. Leaves were tagged and placed in a growth chamber tor acclimatization. Photosynthetic capability of leaves from different origins was determined by measuring the initial and total activity of Ribulose-1, 5-bisphosphate carboxylase/oxygenase (rubisco), but the contribution of Phosphoenolpyruvate carboxylase (PEPCase) to fixation was also examined High CO2 concentration and PPF significantly increased fresh weight and surface area in vitro and after 4 weeks ex vitro. Improved growth was not the result of increased autotrophy in vitro since initial rubisco activity was 10 times lower than that of de novo formed leaves and declined under high CO2 and PPF. Carbon dioxide concentration and PPF had no effect on total activity of rubisco. Low activation state and total activity of rubisco in in vitro leaves is the cause of poor photosynthetic activity in vitro Persistent in vitro leaves after 4 weeks of acclimatization did not have higher total activity of rubisco, but the activation state was 4 times larger than the corresponding activity in vitro which might thus provide for non-negligible contribution to photosynthetic carbon assimilation. The possible inhibition of photosynthesis by the presence of sugar in the medium is discussed.

scholarly journals Structure of Rubisco fromArabidopsis thalianain complex with 2-carboxyarabinitol-1,5-bisphosphate

2018 ◽  
Vol 74 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Karin Valegård ◽  
Dirk Hasse ◽  
Inger Andersson ◽  
Laura H. Gunn
Keyword(s):  
Crystal Structure ◽  
Model Organism ◽  
Carbon Assimilation ◽  
Small Subunit ◽  
Higher Plant ◽  
Bisphosphate Carboxylase ◽  
Structural Framework ◽  
Transition State Analogue ◽  
Subunit Isoforms ◽  
Photosynthetic Carbon Assimilation

The crystal structure of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) fromArabidopsis thalianais reported at 1.5 Å resolution. In light of the importance ofA. thalianaas a model organism for understanding higher plant biology, and the pivotal role of Rubisco in photosynthetic carbon assimilation, there has been a notable absence of anA. thalianaRubisco crystal structure.A. thalianaRubisco is an L8S8hexadecamer comprising eight plastome-encoded catalytic large (L) subunits and eight nuclear-encoded small (S) subunits.A. thalianaproduces four distinct small-subunit isoforms (RbcS1A, RbcS1B, RbcS2B and RbcS3B), and this crystal structure provides a snapshot ofA. thalianaRubisco containing the low-abundance RbcS3B small-subunit isoform. Crystals were obtained in the presence of the transition-state analogue 2-carboxy-D-arabinitol-1,5-bisphosphate.A. thalianaRubisco shares the overall fold characteristic of higher plant Rubiscos, but exhibits an interesting disparity between sequence and structural relatedness to other Rubisco isoforms. These results provide the structural framework to understandA. thalianaRubisco and the potential catalytic differences that could be conferred by alternativeA. thalianaRubisco small-subunit isoforms.

scholarly journals The global mass and average rate of rubisco

2019 ◽  
Vol 116 (10) ◽  
pp. 4738-4743 ◽  
Author(s):  
Yinon M. Bar-On ◽  
Ron Milo
Keyword(s):  
Total Mass ◽  
Carbon Fixation ◽  
Average Rate ◽  
Carbon Assimilation ◽  
Dry Weight ◽  
Effective Rate ◽  
Terrestrial Plants ◽  
Bisphosphate Carboxylase ◽  
Catalytic Rate

Photosynthetic carbon assimilation enables energy storage in the living world and produces most of the biomass in the biosphere. Rubisco (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is responsible for the vast majority of global carbon fixation and has been claimed to be the most abundant protein on Earth. Here we provide an updated and rigorous estimate for the total mass of Rubisco on Earth, concluding it is ≈0.7 Gt, more than an order of magnitude higher than previously thought. We find that >90% of Rubisco enzymes are found in the ≈2 × 1014m2of leaves of terrestrial plants, and that Rubisco accounts for ≈3% of the total mass of leaves, which we estimate at ≈30 Gt dry weight. We use our estimate for the total mass of Rubisco to derive the effective time-averaged catalytic rate of Rubisco of ≈0.03 s−1on land and ≈0.6 s−1in the ocean. Compared with the maximal catalytic rate observed in vitro at 25 °C, the effective rate in the wild is ≈100-fold slower on land and sevenfold slower in the ocean. The lower ambient temperature, and Rubisco not working at night, can explain most of the difference from laboratory conditions in the ocean but not on land, where quantification of many more factors on a global scale is needed. Our analysis helps sharpen the dramatic difference between laboratory and wild environments and between the terrestrial and marine environments.

Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

1990 ◽  
Vol 48 (3) ◽  
pp. 906-907
Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase
Keyword(s):  
Cell Suspension ◽  
Euglena Gracilis ◽  
Carbon Materials ◽  
Three Dimensional ◽  
Peripheral Region ◽  
Plastid Development ◽  
Bisphosphate Carboxylase ◽  
Inorganic Medium ◽  
Ribulose 1 ◽  
Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

Einfluß der Glucose auf die [14C] Thymidin-Einbaurate von Ehrlich-Ascitescarcinomzellen in vitro

1969 ◽  
Vol 08 (02) ◽  
pp. 196-206 ◽  
Author(s):  
Dieter. Kummer
Keyword(s):  
De Novo

ZusammenfassungIn nahezu glucosefreier Suspension von Ehrlich-Ascitescarcinomzellen bewirkt die Zufuhr von Glucose 2,5 × 10–4 bis 10–2 M:1. Hemmung der [14C] Thymidin-Einbaurate in die Zellen.2. Aktivierung des Ribonucleotid-Reductase-Systems und damit Stimulierung der Desoxyribonucleotidsynthese (auch der Thymidintriphosphat-de-novo-Synthese).3. Blockierung der Thymidinkinase über Endprodukthemmung, wodurch die Minderung des [14C] Thymidin-Einbaus in die Zellen erklärbar ist.

Особенности морфогенеза редкого вида Allium neriniflorum (Herb.) Backer в условиях in vitro

2019 ◽  
pp. 37-41 ◽  
Author(s):  
Альбина Шамсуновна Ахметова ◽  
Альфия Ануровна Зарипова
Keyword(s):  
De Novo

Показана возможность эффективного применения метода культуры тканей для размножения Allium neriniflorum (Herb.) Backer. Исследуемый вид является декоративным растением, размножение которого затруднено из-за низкой всхожести семян и ослабленной способности к формированию дочерних луковиц. Разработана технология клонального микроразмножения из стерильных луковиц. В качестве исходного материала использовали семена A. neriniflorum. Подобраны условия стерилизации, позволяющие достичь максимального числа (75 %) жизнеспособных эксплантов. Поверхностную стерилизацию проводили в ламинар-боксе с использованием в качестве стерилизующего агента 0,1 % раствор диацида. Семена сначала обрабатывали 70 % этанолом, затем стерилизующим раствором. Экспозиция стерилизующих растворов составляла от 5 до 9 мин. Показано, что способность к индуцированному морфогенезу существенно зависит от состава питательной среды. Максимальное число луковиц образовывалось на среде QL — 9 шт./эксплант. Исследуемые виды обладали высокой способностью к мультипликации и формированию полноценных растений при подобранных условиях культивирования in vitro. Выявленная морфогенетическая активность зачаточного побега, сегментов чешуй и донца стерильной луковицы A. neriniflorum, проявляющаяся в способности регенерировать побеги de novo, что возможно только в культуре in vitro, обеспечивает формирование полноценных луковиц. Луковицы, полученные in vitro, включали в последующие циклы микроразмножения. Культура тканей и органов in vitro позволяет размножать A. neriniflorum с более высоким коэффициентом размножения. От одной стерильной луковицы можно получить до 7000 луковиц в год. При традиционном вегетативном способе размножения материнская луковица формирует 1, редко 2 дочерние луковицы.

Study of Phosphocalcic Glasses from SiO2-CaO-P2O5 System with and Without Silver II. The bioactivity analysis by FTIR, SEM methods and microbiological study of silver-doped glasses

2017 ◽  
Vol 68 (6) ◽  
pp. 1188-1192
Author(s):  
Daniela Avram ◽  
Nicolae Angelescu ◽  
Dan Nicolae Ungureanu ◽  
Ionica Ionita ◽  
Iulian Bancuta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Body Fluid ◽  
Pathogenic Bacteria ◽  
De Novo ◽  
Microbiological Examination ◽  
Doped Glasses ◽  
P2o5 System ◽  
Scanning Electron

The study in vitro of the glass powders bioactivity was performed by soaking them in simulated body fluid for 3 to 21 days at a temperature of 37�C and pH = 7.20. The synthesis de novo of hydroxyapatite, post soaking was confirmed by Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The study of the antimicrobial activity was performed by microbiological examination on two strains of pathogenic bacteria involved in postoperative nosocomial infections.

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