scholarly journals Effects of Inorganic Phosphate on the Light Dependent Thylakoid Energization of Intact Spinach Chloroplasts

1989 ◽  
Vol 91 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Dieter Heineke ◽  
Mark Stitt ◽  
Hans W. Heldt
Keyword(s):  
Inorganic Phosphate ◽  
Spinach Chloroplasts

HYDROLYSIS OF LECITHIN BY PLANT PLASTID ENZYMES

1955 ◽  
Vol 33 (1) ◽  
pp. 575-589 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Phosphatidic Acid ◽  
Inorganic Phosphate ◽  
Organic Phosphate ◽  
Water Soluble ◽  
Lag Phase ◽  
Carrot Root ◽  
First Order ◽  
Spinach Chloroplasts ◽  
Egg Lecithin ◽  
Hydrolysis Of

Enzymatic liberation of choline from egg lecithin by plastid fractions from sugar beet, spinach, and cabbage leaves and from carrot root was a rapid, first order reaction (up to 70% hydrolysis), and was not preceded by a lag phase. None of the choline-containing products of lecithin degradation (lysolecithin, glycerylphosphorylcholine, or phosphorylcholine) lost choline on incubation with spinach chloroplasts. Inorganic phosphate liberation from lecithin by the plastids was preceded by a lag phase and was much slower than choline liberation. Spinach chloroplasts catalyzed the liberation of inorganic phosphate from L-α-phosphatidic acid and from L-α-glycerophosphate. The water-soluble organic phosphate liberated from lecithin by spinach chloroplasts was identified chromatographically as phosphorylcholine. The ether-soluble organic phosphate produced during the hydrolysis of egg lecithin by carrot plastids was isolated and identified as L-α-phosphatidic acid. These observations suggest that the enzymatic hydrolysis of lecithin by plant plastids involves the following reactions: (1) lecithin → L-α-phosphatidic acid + choline; (2) L-α-phosphatidic acid → inorganic phosphate + diglyceride and/or (3) L-α-phosphatidic acid → glycerophosphate + fatty acids and (4) glycerophosphate → inorganic phosphate + glycerol; and (5) lecithin → phosphorylcholine + diglyceride. The L-α-structure for egg lecithin was confirmed.

ENZYMIC ACTIVITIES OF SUBCELLULAR PARTICLES FROM LEAVES: IV. PHOTOSYNTHETIC PHOSPHORYLATION AND PHOTOSYNTHESIS BY ISOLATED CHLOROPLASTS FROM PEA LEAVES

1959 ◽  
Vol 37 (6) ◽  
pp. 1217-1225 ◽  
Author(s):  
R. M. Smillie ◽  
G. Krotkov
Keyword(s):  
Carbon Dioxide ◽  
Inorganic Phosphate ◽  
Fixed Carbon ◽  
Spinach Chloroplasts ◽  
Green Pea ◽  
Isolated Chloroplasts

Chloroplasts were isolated in 0.35 M NaCl from green pea leaves. Such preparations formed ATP photosyathetically from AMP or ADP and inorganic phosphate. The conditions and cofactors of this reaction were studied. The rates of photosynthetic phosphorylation by isolated pea chloroplasts were compared with photosynthetic phosphorylation by spinach chloroplasts and with photosynthesis by intact pea leaves. The isolated pea chloroplasts also photosynthetically fixed carbon dioxide. The possible roles of chloroplasts and mitochondria in cellular phosphorylations are discussed.

HYDROLYSIS OF LECITHIN BY PLANT PLASTID ENZYMES

1955 ◽  
Vol 33 (4) ◽  
pp. 575-589 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Phosphatidic Acid ◽  
Inorganic Phosphate ◽  
Organic Phosphate ◽  
Water Soluble ◽  
Lag Phase ◽  
Carrot Root ◽  
First Order ◽  
Spinach Chloroplasts ◽  
Egg Lecithin ◽  
Hydrolysis Of

Enzymatic liberation of choline from egg lecithin by plastid fractions from sugar beet, spinach, and cabbage leaves and from carrot root was a rapid, first order reaction (up to 70% hydrolysis), and was not preceded by a lag phase. None of the choline-containing products of lecithin degradation (lysolecithin, glycerylphosphorylcholine, or phosphorylcholine) lost choline on incubation with spinach chloroplasts. Inorganic phosphate liberation from lecithin by the plastids was preceded by a lag phase and was much slower than choline liberation. Spinach chloroplasts catalyzed the liberation of inorganic phosphate from L-α-phosphatidic acid and from L-α-glycerophosphate. The water-soluble organic phosphate liberated from lecithin by spinach chloroplasts was identified chromatographically as phosphorylcholine. The ether-soluble organic phosphate produced during the hydrolysis of egg lecithin by carrot plastids was isolated and identified as L-α-phosphatidic acid. These observations suggest that the enzymatic hydrolysis of lecithin by plant plastids involves the following reactions: (1) lecithin → L-α-phosphatidic acid + choline; (2) L-α-phosphatidic acid → inorganic phosphate + diglyceride and/or (3) L-α-phosphatidic acid → glycerophosphate + fatty acids and (4) glycerophosphate → inorganic phosphate + glycerol; and (5) lecithin → phosphorylcholine + diglyceride. The L-α-structure for egg lecithin was confirmed.

scholarly journals Observations on the phosphate status and intracellular pH of intact cells, protoplasts and chloroplasts from photosynthetic tissue using phosphorus-31 nuclear magnetic resonance

1982 ◽  
Vol 202 (2) ◽  
pp. 429-434 ◽  
Author(s):  
C Foyer ◽  
D Walker ◽  
C Spencer ◽  
B Mann
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Intracellular Ph ◽  
Inorganic Phosphate ◽  
Spinacia Oleracea ◽  
Fundamental Difference ◽  
Asparagus Officinalis ◽  
Intact Cells ◽  
Spinach Chloroplasts ◽  
Nuclear Magnetic

Individual pools of intracellular inorganic phosphate (Pi) can be observed in the dark in intact cells, protoplasts and chloroplasts from photosynthetic tissue by using 31P nuclear magnetic resonance (n.m.r.). Estimates for the pH of vacuolar and extravacuolar compartments are reported although it is shown that intracellular pH is determined by the pH of the suspending medium. Mannose treatment of asparagus (Asparagus officinalis) cells and spinach (Spinacia oleracea) protoplasts results in the inhibition of photosynthesis. The mechanism of mannose phosphate sequestration of free Pi is supported by the 31P n.m.r. spectra of mannose-treated tissue. There is a fundamental difference in 31 P n.m.r. spectra of mannose-treated spinach protoplasts and asparagus cells, reflecting a difference in the availability of vacuolar Pi for cellular metabolism in these species. The 31P n.m.r. spectrum of intact spinach chloroplasts is reported.

Plasmalemma localisation of inorganic phosphate in B cells pancreas

1978 ◽  
Vol 36 (2) ◽  
pp. 528-529
Author(s):  
F. B. P. Wooding ◽  
K. Pedley ◽  
N. Freinkel ◽  
R. M. C. Dawson
Keyword(s):  
Electron Microscope ◽  
B Cells ◽  
B Cell ◽  
Pancreatic Islets ◽  
High Glucose ◽  
Lead Acetate ◽  
Inorganic Phosphate ◽  
Slight Modification ◽  
Uranyl Acetate ◽  
Lead Phosphate

Freinkel et al (1974) demonstrated that isolated perifused rat pancreatic islets reproduceably release up to 50% of their total inorganic phosphate when the concentration of glucose in the perifusion medium is raised.Using a slight modification of the Libanati and Tandler (1969) method for localising inorganic phosphate by fixation-precipitation with glutaraldehyde-lead acetate we can demonstrate there is a significant deposition of lead phosphate (identified by energy dispersive electron microscope microanalysis) at or on the plasmalemma of the B cell of the islets (Fig 1, 3). Islets after incubation in high glucose show very little precipitate at this or any other site (Fig 2). At higher magnification the precipitate seems to be intracellular (Fig 4) but since any use of osmium or uranyl acetate to increase membrane contrast removes the precipitate of lead phosphate it has not been possible to verify this as yet.

Relation between intravascular electrolyte level and course of parturition in dairy cows

2013 ◽  
Vol 41 (05) ◽  
pp. 289-296 ◽  
Author(s):  
K. Seyrek-Intas ◽  
K. Failing ◽  
G. Yilmazbas Mecitoglu ◽  
H. Bostedt ◽  
D. Seyrek-Intas
Keyword(s):  
Dairy Cows ◽  
Inorganic Phosphate ◽  
Post Partum ◽  
Total Calcium ◽  
Normal Delivery ◽  
P Values ◽  
Normal Birth ◽  
Factors Influencing ◽  
Electrolyte Homeostasis ◽  
Convalescence Phase

Summary Objective: To determine the intravascular electrolyte status in dairy cows with respect to age and different courses of parturition to clarify etiological factors influencing peri- or intrapartal imbalances of electrolyte homeostasis. Material and methods: A total of 64 cows at birth were evaluated (primiparous n = 34, pluriparous n = 30). Thirty-three cows showed normal delivery, while 31 cows had a complicated birth. Blood samples were collected intra partum (i. p.) and 2, 4, 6, 8, 12, 16, 24 h post partum (p. p.) as well as [2, 3, 4, 5, 7, 10 days p. p. and levels of total calcium (Catotal), ionized calcium (Caion), inorganic phosphate (Pa), Mg, Na, K, Cl were determined. Results: The results revealed that electrolytes show great fluctuation during and immediately p. p. in relation to age. Already during parturition pluriparous cows had a lower Catotal and Pa concentration compared to primiparous animals. Cows with dystocia exhibited a more intensive and longer lasting decrease of Ca compared to cows with normal birth. In relation to age and severity of birth Pa concentration showed a differing but basically typical course for this electrolyte. Mg, Na, K and Cl concentrations were higher during and immediately after birth compared to p. p. values. Until day 10 p. p. these electrolyte concentrations declined more in older cows with dystocia compared to younger animals. However, the influence of dystocia on concentration of these electrolytes was milder in contrast to Ca and Pa. Conclusions: In summary, primarily older cows are predisposed to imbalances of electrolyte homeostasis intra partum and at the beginning of the lactation. These changes are potentiated in case of complications during parturition. Intravascular Catotal, Caion as well as Pa are most severely affected. Clinical relevance: These results may constitute the basis for a comprehensive metaphylaxis during the peripartal period, especially in cows after dystocia, to positively influence the early convalescence phase.

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