Phosphorus deficiency and phosphate uptake in the blue-green alga Anacystis nidulans

1968 ◽  
Vol 14 (4) ◽  
pp. 341-348 ◽  
Author(s):  
J. C. Batterton ◽  
C. Van Baalen
Keyword(s):  
Phosphorus Content ◽  
Phosphate Uptake ◽  
Phosphorus Deficiency ◽  
Normal Growth ◽  
Anacystis Nidulans ◽  
Anaerobic Conditions ◽  
Atp Formation ◽  
Transport Chain ◽  
Dark Fixation ◽  
Phosphate Incorporation

The normal level of phosphorus in Anacystis nidulans is approximately 3.7 μg Pi/mm3 cells. This value fell to 0.5 μg Pi/mm3 cells under prolonged starvation. Even at low cellular phosphate levels, cells were viable and continued to divide slowly. With cells containing approximately 1.5 μg Pi/mm3 cells a rapid dark uptake (15 minutes) of 0.8 μg Pi/mm3 cells was found. Data obtained in the rapid dark fixation suggest that approximately 25% of the total cellular phosphorus is possibly bound on specific sites. Light had little effect on this first phase of phosphate uptake. The subsequent uptake to the normal phosphorus content per cell and return to normal growth rate required light and nitrogen.Coincident with the rapid dark phosphate incorporation, synthesis of ATP began and continued, rising far above the level of normal cells. The rate of ATP formation was not influenced by light, but was blocked by anaerobic conditions or several classical inhibitors of the electron transport chain.

SUBSTRATE-DEPENDENT PHOSPHORYLATION IN RESTING CELLS OF PSEUDOMONAS AERUGINOSA

1961 ◽  
Vol 7 (1) ◽  
pp. 91-97
Author(s):  
G. A. Strasdine ◽  
J. J. R. Campbell ◽  
H. P. C. Hogenkamp ◽  
J. N. Campbell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Electron Transport Chain ◽  
Phosphate Uptake ◽  
Growth Yield ◽  
Resting Cells ◽  
Resting Cell ◽  
Transport Chain ◽  
Oxidation Of Glucose ◽  
Phosphate Incorporation ◽  
Stimulation Of

Resting cell suspensions of Pseudomonas aeruginosa exhibited substrate-dependent phosphorylation and most of the phosphate appeared in the nucleic acid fraction. The amount of P32 incorporated was a function of substrate concentration. When equivalent amounts of glucose, gluconate, or 2-ketogluconate were used as substrate, it was found that the more oxidized substrates supported appreciably less P32 incorporation, thus indicating that phosphorylation is coincident with the passage of electrons to oxygen by way of the electron transport chain. These data serve to illustrate that the practice of determining the amount of energy available from the dissimilation of a substrate by measuring growth yield can be in error since equivalent quantities of glucose, gluconate, and 2-ketogluconate supported equal amounts of growth. The P:O ratios obtained with glucose as substrate were of the order of 0.01. Phosphorylation was not sensitive to dinitrophenol or sodium fluoride but was completely inhibited by cyanide. Chloramphenicol, at a concentration which inhibited protein synthesis, caused a twofold stimulation of phosphate incorporation. Pyocyanine, which stops the oxidation of glucose at the 2-ketogluconate stage, completely inhibited phosphate uptake. The action of pyocyanine on both oxidation and phosphorylation could be reversed by magnesium. When extracts of this organism were studied, it was found that under all conditions the addition of oxidizable substrates decreased P32 incorporation.

Modelling phosphorus uptake in microalgae

2018 ◽  
Vol 46 (2) ◽  
pp. 483-490 ◽  
Author(s):  
Dipali Singh ◽  
Ladislav Nedbal ◽  
Oliver Ebenhöh
Keyword(s):  
Circular Economy ◽  
Molecular Mechanisms ◽  
Phosphorus Content ◽  
Phosphate Uptake ◽  
Phosphorus Uptake ◽  
Agricultural Runoff ◽  
P Uptake ◽  
Modern Agriculture ◽  
P Recovery ◽  
And Storage

Phosphorus (P) is an essential non-renewable nutrient that frequently limits plant growth. It is the foundation of modern agriculture and, to a large extent, demand for P is met from phosphate rock deposits which are limited and becoming increasingly scarce. Adding an extra stroke to this already desolate picture is the fact that a high percentage of P, through agricultural runoff and waste, makes its way into rivers and oceans leading to eutrophication and collapse of ecosystems. Therefore, there is a critical need to practise P recovery from waste and establish a circular economy applicable to P resources. The potential of microalgae to uptake large quantities of P and use of this P enriched algal biomass as biofertiliser has been regarded as a promising way to redirect P from wastewater to the field. This also makes the study of molecular mechanisms underlying P uptake and storage in microalgae of great interest. In the present paper, we review phosphate models, which express the growth rate as a function of intra- and extracellular phosphorus content for better understanding of phosphate uptake and dynamics of phosphate pools.

Effects of preillumination with light of different wavelengths on subsequent dark CO2-fixation in Chlorella cells

1970 ◽  
Vol 48 (6) ◽  
pp. 1203-1207 ◽  
Author(s):  
Shigetoh Miyachi ◽  
Daisuke Hogetsu
Keyword(s):  
Blue Light ◽  
Co2 Fixation ◽  
Red Light ◽  
Anaerobic Conditions ◽  
Nitrogen Gas ◽  
Pep Carboxylase ◽  
Radioactive Carbon ◽  
Initial Fixation ◽  
Dark Fixation ◽  
Dark Co2 Fixation

The effects of preillumination with monochromatic red or blue light on the subsequent dark 14CO2-fixation in Chlorella cells were studied under aerobic as well as anaerobic conditions. When the cell suspension was made aerobic by bubbling air (CO2-free) throughout the periods of preillumination and the following dark 14CO2-fixation, the initial fixation product was mainly PGA. The radioactive carbon first incorporated in PGA was transferred mostly to aspartate during the later periods of dark 14CO2-fixation. The rate of 14C-incorporation into aspartate after preillumination with blue light was 2 to 3 times as high as that observed after red-light pretreatment. The observations support our previous inference that the activity of PEP carboxylase in Chlorella cells is stimulated by preillumination with blue light. When nitrogen gas was used during preillumination and the subsequent dark fixation, the radioactivity of 14C incorporated during the initial enhanced 14CO2-fixation was eventually transferred to alanine and lactate. The increase in radioactivity of alanine and lactate was more pronounced during dark fixation after preillumination with red light than after preillumination with blue light.

Internal Phosphorus Flows During Development of Phosphorus Stress in Stylosanthes hamata

1990 ◽  
Vol 17 (4) ◽  
pp. 451 ◽  
Author(s):  
FW Smith ◽  
WA Jackson ◽  
PJV Berg
Keyword(s):  
Root Growth ◽  
Growth Rates ◽  
Shoot Growth ◽  
Phosphorus Content ◽  
Phosphorus Deficiency ◽  
Root Weight ◽  
Maximal Growth ◽  
Apparent Lack ◽  
Phosphorus Stress ◽  
Stylosanthes Hamata

Partitioning and net transfer of phosphorus between shoots and roots in the tropical forage legume Stylosanthes hamata cv. Verano during the development of phosphorus deficiency has been studied. Plants were stressed by either growing them in dilute flowing culture on continuously maintained external phosphorus concentrations that were inadequate for maximal growth, or by transferring plants of varying phosphorus status to phosphorus-free media. An external phosphorus concentration of 1 �M P was found to be just adequate for maximal growth of S. hamata. Phosphorus stress caused rapid and substantial increases in root weight percentage. It is proposed that this represents an important adaptive mechanism for maximising phosphorus uptake by S. hamata growing in phosphorus-deficient soils. Roots contained the minimum proportion of the plant's phosphorus content when root phosphorus concentrations were 8-10 �mol P g-1 root, and shoot phosphorus concentrations were 16-20 �mol P g-1 shoot. When tissue concentrations were less than these values, plants suffered from phosphorus stress and phosphorus was either preferentially retained by the roots or rapidly transferred from shoots to roots, reducing the growth rates of shoots, but permitting root growth to continue. Upon reducing the external phosphorus supply to plants whose root phosphorus concentrations exceeded 8 to 10 �mol P g-1 root, excess phosphorus was rapidly transferred from the root to the shoot to maintain shoot growth rates. The mobility of phospborus within the plant, and the apparent lack of any delay in transferring phosphorus from shoots to roots as phosphorus stress developed, represent another adaptive feature that is likely to be important to the successful growth of S. hamata in low phosphorus soils. When the phosphorus supply was limited, the plant's resources were directed toward maintaining root growth. Even extremely phosphorus deficient plants, in which shoot growth had ceased, maintained linear rates of root growth. These linear rates were related to the total phosphorus content of the plant. In the latter stages of phosphorus deprivation, linear rates of root growth were maintained by remobilisation of phosphorus from the older parts of the root system to sustain the phosphorus supply to the root meristems.

scholarly journals EXPERIMENTAL RICKETS IN RATS

1922 ◽  
Vol 35 (4) ◽  
pp. 447-466 ◽  
Author(s):  
A. M. Pappenheimer ◽  
G. F. McCann ◽  
T. F. Zucker ◽  
Keyword(s):  
Bone Formation ◽  
Phosphorus Content ◽  
Potassium Phosphate ◽  
Normal Growth ◽  
Egg Albumin ◽  
Normal Bone ◽  
Butter Fat

1. Casein phosphorus does not completely prevent the development of rickets when substituted in Diet 84 in amount equivalent to a protective dose of basic potassium phosphate. 2. The protection given by lecithin is equivalent to its phosphorus content. 3. The protection given by yeast is at least proportional to its phosphorus content. An amount carrying sufficient vitamine B to promote growth, but insufficient to provide adequate phosphorus, does not prevent rickets. 4. Vitamine A, in the form of butter or butter fat to the amount of 10 per cent of the diet, neither prevents nor cures rickets. 5. The substitution of 10 per cent of egg albumin in Diet 84 improves the nutrition, but does not prevent rickets. 6. The addition of meat to Diet 84, thereby supplying an abundance of phosphorus, promotes normal growth and normal bone formation. A diet consisting solely of meat and flour is inadequate for proper growth, and leads to changes in the bones comparable with those observed on a diet low in calcium, but rich in phosphorus. 7. A diet has been found which contains the necessary food elements for approximately normal growth, and in which the only known deficiency is phosphorus. This leads regularly to the production of rickets.

Zum Mechanismus des photosynthetischen Elektronentransportes in isolierten Chloroplasten

1965 ◽  
Vol 20 (2) ◽  
pp. 143-147 ◽  
Author(s):  
Achim Trebst ◽  
Elfriede Pistorius
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Phosphorylation Site ◽  
Atp Formation ◽  
Point Of Entry ◽  
Transport Chain ◽  
Endogenous Compounds ◽  
Cyclic Photophosphorylation ◽  
Photosynthetic Reactions ◽  
High Concentrations

The behavior of 2,3,5,6-tetramethyl-p-phenylendiamine (DAD) in photosynthetic reactions of isolated chloroplast fragments was compared with that of N-tetramethyl-p-phenylendiamine (TMPD). Both reverse the DCMU-inhibition of photosynthetic NADP-reduction. The DAD-system (at high concentrations of DAD), is coupled to a stoichiometric ATP-formation, whereas the TMPD-system is not. This shows that p-phenylendiamines, depending on their constitution, may react with components of the electron transport chain of chloroplasts before or after the phosphorylation site, and locates the phosphorylation step of photosynthetic phosphorylation between two endogenous compounds in that part of the electron transport chain, which connects the two light reactions of photosynthesis.At lower concentrations of DAD the diminished NADP-reduction is no longer coupled to ATP-formation, indicating a second point of entry of electrons from DAD into the electron transport chain. DAD, furthermore, is a cofactor of cyclic photophosphorylation. It therefore behaves like DCPIP, but the rates of the DAD-system are higher.

scholarly journals Cross talk between photo-pigments and graphene electron cloud - Designing a biodiode

2017 ◽  
Author(s):  
Sanhita Ray ◽  
Sayantani Sen ◽  
Alakananda Das ◽  
Anirban Bose ◽  
Anirban Bhattacharyya ◽  
...  
Keyword(s):  
Schottky Diode ◽  
Electron Transport Chain ◽  
Normal Growth ◽  
Electron Cloud ◽  
Bacterial Biofilm ◽  
Bacterial Metabolism ◽  
Transport Chain ◽  
Semiconducting Properties ◽  
Voltage Dependent ◽  
Graphene Electron

AbstractWe report emergence of a new electrical material by growing photosynthetic biofilm on a Dirac material, graphene. The material showed new conducting as well as semiconducting properties. Frequency dependent capacitive spectra further indicated presence of electrical isosbestic points(at 0.8 and 9MHz), implying two state dieletric transitions at critical frequencies. A notable reult was a Schottky diode like behavior in the IV curve. Voltage dependent conductance with conductance peaks near the Schottky diode threshold was observed. We obtained facilitated growth of photosynthetic biofilm in presence of graphene. Lastly higher bacterial metabolism i was seen in the biofilm in contact with graphene as compared to its normal growth condition. For this zero band gap Dirac material this can only be interpreted as coupling of the electron transport chain of the bacterial biofilm and the graphene electron cloud.

scholarly journals KREBER`S ADVENTURES: COMPUTER GAME ABOUT THE ATP FORMATION

2015 ◽  
Vol 13 ◽  
pp. 11
Author(s):  
F. J. Baêta ◽  
B. M. Souza ◽  
G. B. Marinhoi ◽  
J. G. Andrade ◽  
J. C. Souza ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Krebs Cycle ◽  
Computer Game ◽  
Usability Testing ◽  
Digital Games ◽  
Glycolytic Pathway ◽  
Pedagogical Practice ◽  
Atp Formation ◽  
Transport Chain

Introduction: Biochemistry, as well as other subjects related to molecular area, have several abstract and difficult concepts to be understood, therefore, many educational innovations have been developed, highlighting the digital games. The digital games feature a playful and motivational character that encourages students during the concepts learning, with a different way to learning the concepts studied. Objectives: The objective of this study was the development of a computer game focused on the concepts of ATP formation, including the glycolytic pathway, Krebs cycle and Electron Transport Chain, as well as aspects related to the regulation, and evaluate the usability of it, as well as some evidence of its educational potential. Material and methods: The development of the game followed the following steps: definition of the subject; understanding of game developer (it was chosen the GameMaker); storyboard creation of the game; prototyping, implementation and usability testing. For the evaluation, inspection usability was performed (without involving end users) and subsequently the cognitive route and the usability questionnaire (the latter two with students of the discipline of Biochemistry). Results: The game approached the energy metabolism in three phases: the glycolytic pathway, Krebs cycle and electron transport chain. Each phase has a different purpose, with some questions about the ways. To complete the game, you must correctly answer the questions, avoid the obstacles and achieve the goals of each phase. After usability testing, it found that users could, in a playful manner, actively interact with the content addressed and, through the difficulties presented in the game, had the opportunity to expand and review their knowledge. Conclusions: The game was identified as a motivating and innovative proposal for  teaching, and it had good usability for undergraduate students. The ludic worked as a pedagogical practice encourages student for learning and may assist in the construction of knowledge.

The influence of mineral nutrition on the susceptibility of apple trees to infection by Trametes (Polystictus) versicolor

1968 ◽  
Vol 8 (33) ◽  
pp. 436 ◽  
Author(s):  
GC Wade
Keyword(s):  
Mineral Nutrition ◽  
Phosphorus Content ◽  
Marked Effect ◽  
Phosphorus Deficiency ◽  
Analytical Data ◽  
Sand Culture ◽  
Slight Effect ◽  
Apple Trees ◽  
Highly Pathogenic ◽  
Woody Tissues

Trametes (Polysticus) versicolor is shown to be highly pathogenic to apple trees grown in sand culture with a nutrient deficient in phosphorus. Less vigorous attack occurred on trees deficient in magnesium, potassium or calcium; but nitrogen deficient trees, or those receiving complete nutrients, developed no macroscopically visible symptoms following inoculation. The fungus penetrated all inoculated limbs irrespective of treatment, but in complete and nitrogen deficient trees no attack on woody tissues developed. Phosphorus deficiency had only a slight effect on phosphorus content of leaves, but a very marked effect on bark and wood phosphorus. Analytical data presented in the paper demonstrates several interactions between elements.

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