Inactivation of Photosynthetic O2 Evolution in the Cyanobacterium Anacystis nidulans PCC 6301: Influence of Nitrogen Metabolites and Divalent Cation Concentration

1991 ◽  
Vol 46 (11-12) ◽  
pp. 1024-1032 ◽  
Author(s):  
Gudrun Wälzlein ◽  
Elfriede K. Pistorius
Keyword(s):  
Photosystem Ii ◽  
Nitrogen Source ◽  
Divalent Cation ◽  
Water Oxidation ◽  
Divalent Cations ◽  
Nitrogen Deficiency ◽  
Anacystis Nidulans ◽  
O2 Evolution ◽  
Cation Deficiency

Abstract An investigation about the in vivo inactivation of photosynthetic water oxidation has been carried out in the cyanobacterium Anacystis nidulans (Synechococcus PCC 6301). Photosystem II and photosystem I activity as well as the relative amount of the D1 and manganese stabilizing peptide of photosystem II were determined after growing the cells in nutrient media with variations in the nitrogen source and the concentration of the major divalent cations (Mg2+ and Ca2+). The results show a rapid inactivation of water oxidation in A. nidulans in response to nitrogen deficiency and in response to reduced Mg2+ and Ca2+ concentrations. The inactivation of water oxidation observed under divalent cation deficiency could be greatly accelerated when L-amino acids instead of ammonia or nitrate were used as nitrogen source. Under these conditions inactivation of water oxidation correlated with a rapid loss of D1 and with a slower loss of the manganese stabilizing peptide from photosystem II. A possible regulation of the photosystem II activity in A. nidulans by nitrogen metabolites is suggested.

scholarly journals Fast enzymatic HCO3- dehydration supports photosynthetic water oxidation in Photosystem II from pea

2021 ◽  
Author(s):  
Alexandr V. Shitov ◽  
Vasily V. Terentyev ◽  
Govindjee Govindjee
Keyword(s):  
Photosystem Ii ◽  
Pisum Sativum ◽  
Water Oxidation ◽  
Photochemical Reactions ◽  
O2 Evolution ◽  
Donor Side ◽  
Psii Photochemistry ◽  
Similar Dependence ◽  
Enzymatic Nature ◽  
Photosynthetic Water Oxidation

Carbonic anhydrase (CA) activity, associated with Photosystem II (PSII) from Pisum sativum, has been shown to enhance water oxidation. But, the nature of the CA activity, its origin and role in photochemistry has been under debate, since the rates of CA reactions, measured earlier, were less than the rates of photochemical reactions. Here, we demonstrate high CA activity in PSII from Pisum sativum, measured by HCO3- dehydration at pH 6.5 (i.e. under optimal condition for PSII photochemistry), with kinetic parameters Km of 2.7 mM; Vmax of 2.74·10-2 mM·sec-1; kcat of 1.16·103 sec-1 and kcat/Km of 4.1·105 M-1 sec-1, showing the enzymatic nature of this activity, which kcat exceeds by ~13 times the rate of PSII, as measured by O2 evolution. The similar dependence of HCO3- dehydration, of the maximal quantum yield of photochemical reactions and of O2 evolution on the ratio of chlorophyll/photochemical reaction center II demonstrate the interconnection of these processes on the electron donor side of PSII. Since the removal of protons is critical for fast water oxidation, and since HCO3- dehydration consumes a proton, we suggest that CA activity, catalyzing very fast removal of protons, supports efficient water oxidation in PSII and, thus, photosynthesis in general.

Investigations about various Possible Functions of the L -Amino Acid Oxidase in the Cyanobacterium Anacystis nidulans

1989 ◽  
Vol 44 (5-6) ◽  
pp. 370-377 ◽  
Author(s):  
Elfriede K. Pistorius ◽  
Regine Kertsch ◽  
Susanne Faby
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Divalent Cation ◽  
Anacystis Nidulans ◽  
Acid Oxidase ◽  
Sole Nitrogen Source ◽  
Amino Acid Oxidase ◽  
Cation Concentration ◽  
Arginine Catabolism ◽  
Photosystem Ii Activity

Abstract The cyanobacterium A nacystis nidulans was grown on nitrate or L-arginine as sole nitrogen source and in the presence of different divalent cation concentrations (1 mᴍ MgSO4 and 0.1 mᴍ CaCl2 or 0.1 mᴍ MgSO4 and 0.05 mᴍ CaCl2). The L-amino acid oxidase previously reported to be present in Anacystis nidulans (E . K. Pistorius and A. E. Gau, Biochim. Biophys. Acta 849, 203, 1986) was shown to be involved in L-arginine catabolism in cells grown with the lower divalentcation concentration. Under these conditions L-arginine was partly degraded via 2-ketoarginine and 4-guanidinobutyrate. On the other hand, at higher cation concentrations the ʟ-amino acid oxidase activity seem ed to be not sufficient to provide enough NH4+ from ʟ-arginine for cell growth. Under those conditions photosystem II activity was initially reduced, and growth on ʟ-arginine could only start after photosystem II activity increased again and after arginase was induced. The arginase pathway was functional in A . nidulans grown on ʟ-arginine independently of the divalent cation concentration in the medium. A tentative scheme of the various functiona roles of the ʟ-amino acid oxidase protein in A . nidulans is given. This model combines the here presented and the previous results and suggests that the ʟ-amino acid oxidase is functional in photosynthetic and respiratory activities as well as in ʟ-arginine degradation in A . nidulans. All these activities of the ʟ-amino acid oxidase protein are greatly influenced by the divalent cation concentration in the growth medium.

In vivo bicarbonate requirement for water oxidation by Photosystem II in the hypercarbonate-requiring cyanobacterium Arthrospira maxima

2007 ◽  
Vol 101 (11-12) ◽  
pp. 1865-1874 ◽  
Author(s):  
Damian Carrieri ◽  
Gennady Ananyev ◽  
Tyler Brown ◽  
G. Charles Dismukes
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Arthrospira Maxima

scholarly journals Insights in Behavior of Variably Formulated Alginate-Based Microcapsules for Cell Transplantation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Pia Montanucci ◽  
Silvia Terenzi ◽  
Claudio Santi ◽  
Ilaria Pennoni ◽  
Vittorio Bini ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Chemical Properties ◽  
Live Cells ◽  
High Performing ◽  
Physical Chemical ◽  
Degenerative Disorders ◽  
Selection Of ◽  
Better Than

Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M) enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation,in vitroandin vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.

A NEW NON-PROTEIN NITROGEN SOURCE FOR RUMINANTS

1969 ◽  
Vol 49 (2) ◽  
pp. 135-141 ◽  
Author(s):  
L. P. Milligan ◽  
A. R. Robblee ◽  
J. C. Wood ◽  
W. C. Kay ◽  
S. K. Chakrabartty
Keyword(s):  
Nitrogen Source ◽  
Dietary Supplement ◽  
Nitrogen Retention ◽  
Feeding Trial ◽  
Short Term ◽  
Protein Nitrogen ◽  
Rumen Microorganisms ◽  
Production Of Ammonia

The preparation of a polymer of urea and furfural containing 23.2% nitrogen is described. This product was converted by rumen microorganisms in vitro to ammonia at a rate approximately one-seventh that of conversion of urea to ammonia. Use of the polymer as a dietary supplement in a feeding trial with lambs improved nitrogen retention over that of unsupplemented controls by 3.45 g of nitrogen retained per day, while an isonitrogenous quantity of supplemental urea improved nitrogen retention by 0.51 g of nitrogen retained per day. The blood urea pattern, throughout the day, of lambs adapted to control, urea-supplemented and urea–furfural polymer-supplemented rations indicated a slow, prolonged production of ammonia from the latter supplement and very rapid, short-term degradation of urea in vivo.

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