A short overview of chlorophyll biosynthesis in algae

Biologia ◽  
2008 ◽  
Vol 63 (6) ◽  
Author(s):  
Eliška Gálová ◽  
Iveta Šalgovičová ◽  
Viktor Demko ◽  
Katarína Mikulová ◽  
Andrea Ševčovičová ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Metabolic Activity ◽  
Chlorophyll Biosynthesis ◽  
Enzymatic Reaction ◽  
Continuous Light ◽  
Present Knowledge ◽  
The Other ◽  
Natural Pigments ◽  
Short Overview

AbstractChlorophylls are the most abundant classes of natural pigments and their biosynthesis is therefore a major metabolic activity in the ecosphere. Two pathways exist for chlorophyll biosynthesis, one taking place in darkness and the other requiring continuous light as a precondition. The key process for Chl synthesis is the reduction of protochlorophyllide (Pchlide). This enzymatic reaction is catalysed by two different enzymes — DPOR (dark-operative Pchlide oxidoreductase) or the structurally distinct LPOR (light-dependent Pchlide oxidoreductase). DPOR which consists of three subunits encoded by three plastid genes in eukaryotes was subject of our study. A short overview of our present knowledge of chlorophyll biosynthesis in Chlamydomonas reinhardtii in comparison with other plants is presented.

scholarly journals Endogenous Fluctuations of DNA Topology in the Chloroplast of Chlamydomonas reinhardtii

1998 ◽  
Vol 18 (12) ◽  
pp. 7235-7242 ◽  
Author(s):  
Maria L. Salvador ◽  
Uwe Klein ◽  
Lawrence Bogorad
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Chloroplast Genome ◽  
Continuous Light ◽  
Dna Supercoiling ◽  
Dna Topology ◽  
Chloroplast Gene ◽  
Chloroplast Gene Expression ◽  
Endogenous Fluctuations ◽  
Unicellular Green Alga ◽  
In Cells

ABSTRACT DNA supercoiling in the chloroplast of the unicellular green algaChlamydomonas reinhardtii was found to change with a diurnal rhythm in cells growing in alternating 12-h dark–12-h light periods. Highest and lowest DNA superhelicities occurred at the beginning and towards the end of the 12-h light periods, respectively. The fluctuations in DNA supercoiling occurred concurrently and in the same direction in two separate parts of the chloroplast genome, one containing the genes psaB, rbcL, andatpA and the other containing the atpB gene. Fluctuations were not confined to transcribed DNA regions, indicating simultaneous changes in DNA conformation all over the chloroplast genome. Because the diurnal fluctuations persisted in cells kept in continuous light, DNA supercoiling is judged to be under endogenous control. The endogenous fluctuations in chloroplast DNA topology correlated tightly with the endogenous fluctuations of overall chloroplast gene transcription and with those of the pool sizes of most chloroplast transcripts analyzed. This result suggests that DNA superhelical changes have a role in the regulation of chloroplast gene expression in Chlamydomonas.

Onkonephrologie am Beispiel des Plasmazellmyeloms – Was Nephrologen und Hämatoonkologen voneinander lernen können

2020 ◽  
Vol 145 (12) ◽  
pp. 828-835
Author(s):  
Ulf Schönermarck ◽  
Marcus Hentrich ◽  
Florian Bassermann ◽  
Sebastian Theurich ◽  
Michael Fischereder
Keyword(s):  
Multiple Myeloma ◽  
Renal Insufficiency ◽  
Kidney Function ◽  
Plasma Cell ◽  
The Other ◽  
Therapeutic Options ◽  
Short Overview ◽  
Timely Diagnosis ◽  
Other Hand ◽  
Nephrological Care

AbstractPlasma cell diseases, in particular multiple myeloma, represent an interdisciplinary challenge for oncologists and nephrologists. Patients often present initially with kidney problems to a nephrologist, requiring timely diagnosis and referral to an oncologist for treatment. On the other hand, a relevant part of patients will experience a – mostly temporary – decline in kidney function during the treatment course, which may require nephrological care. In any case, renal insufficiency can affect the therapeutic options. This article provides a short overview about common nephrological factors and complications which impact on the manifestation and course of treatment in patients with plasma cell diseases.

The European Private Company - Entering the Scene or Lost in Discussion?

2009 ◽  
Vol 10 (8) ◽  
pp. 1321-1332 ◽  
Author(s):  
Daniel Kornack
Keyword(s):  
European Commission ◽  
The Other ◽  
Private Company ◽  
Short Overview ◽  
European Institutions ◽  
Draft Statute ◽  
Basic Features ◽  
Societas Privata Europaea ◽  
European Private Company

More than a year has passed since the European Commission introduced the European Private Company (Societas Privata Europaea, SPE) in June 2008. What has become of the draft statute? This paper is meant to give a short overview of its basic features, the other European institutions' discussions and statements, the problems that prevented the proposal from being adopted so far and possible solutions that were introduced.

Regulation der Chlorophyllbiosynthese. Lidit- und entwicklungsbedingte Aktivitätsänderungen von vier aufeinander folgenden Enzymen der Porphyrin- und Chlorophyllbiosynthesekette / Regulation of Chlorophyll Biosynthesis. Changes in Activity of Four Consecutive Enzymes in the Porphyrin and Chlorophyll Biosynthesis Chain during Development and Illumination

1973 ◽  
Vol 28 (1-2) ◽  
pp. 45-58 ◽  
Author(s):  
Hansjörg A. W. Schneider
Keyword(s):  
Nucleic Acid ◽  
Chlorophyll Biosynthesis ◽  
Acid Synthesis ◽  
Chlorophyll Synthesis ◽  
The Other ◽  
Tissue Cultures ◽  
Leaf Tissues ◽  
Porphyrin Synthesis

The activities of enzymes related with chlorophyll and porphyrin synthesis have been examined during development and greening of young corn leaves. The enzymes succinyl-CoA-synthetase (SCoAS), δ-amino-levulinate synthetase (ALAS), δ-amino-levulinate dehydratase (ALAD) and the enzymes involved in porphobilinogenase (PBGA) were under investigaton. When leaves are illuminated and chlorophyll synthesis begins the activity of ALAD is not influenced. The activity of PBGA and SCoAS are slightly higher than in darkness, but the changes are below the range affecting chlorophyll biosynthesis. ALA, however, is only synthetized in the light. Synthesis ceases immediately when illuminiation ist stopped, indicating'that in darkness ALAS is not active. On the other hand ALAS is active in dark grown roots, tubers and other non-leaf tissues. Feeding the plant with succinate, glycine or α-keto-glutarate has no effect on chlorophyll synthesis, but the amount of ALA is reduced, whereas sucrose promotes its accumulation. The results are discussed with completely antitethaal results obtained with tissue cultures of tobacco and are integrated into a scheme which excludes the contrariety of hypotheses deduced from experi- ments with inhibitors of protein and nucleic acid synthesis. It is suggested that the varying results are caused by the action of light on different stages in differentiation of plastids and cells. In contrast to the enzymes SCoAS, ALAD and PBGA whose activities were determined in vitro, ALAS was assayed in vivo by means of the accumulation of (5-amino-levulinate (ALA) after blocking the enzyme ALAD by levulinate (LA). Optimum accumulation is observed when the concentration is about 2 · 10-2 м. LA is not converted to ALA in appreciable amounts. This could be proved by feeding the plants with 14C-LA which was prepared from uniformly labeled 14C-fructose.

scholarly journals Toxin–Antitoxin Systems in Bacillus subtilis

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 262 ◽  
Author(s):  
Sabine Brantl ◽  
Peter Müller
Keyword(s):  
Bacillus Subtilis ◽  
Physiological Role ◽  
Present Knowledge ◽  
The Other ◽  
Type I ◽  
Type Ii ◽  
Free Living ◽  
Bacterial Chromosomes ◽  
Maintenance Systems ◽  
Living Bacteria

Toxin–antitoxin (TA) systems were originally discovered as plasmid maintenance systems in a multitude of free-living bacteria, but were afterwards found to also be widespread in bacterial chromosomes. TA loci comprise two genes, one coding for a stable toxin whose overexpression kills the cell or causes growth stasis, and the other coding for an unstable antitoxin that counteracts toxin action. Of the currently known six types of TA systems, in Bacillus subtilis, so far only type I and type II TA systems were found, all encoded on the chromosome. Here, we review our present knowledge of these systems, the mechanisms of antitoxin and toxin action, and the regulation of their expression, and we discuss their evolution and possible physiological role.

NONTRIVIAL RELATIONS BETWEEN GPDs AND TMDs>

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2973-2983 ◽  
Author(s):  
ANDREAS METZ ◽  
STEPHAN MEISSNER ◽  
MARC SCHLEGEL
Keyword(s):  
Transverse Momentum ◽  
Present Knowledge ◽  
The Other ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
Generalized Parton Distributions ◽  
Model Independent ◽  
The One

The present knowledge about nontrivial relations between generalized parton distributions for a spin-1/2 hadron on the one hand and transverse momentum dependent distributions on the other is reviewed. While various relations can be found in the framework of simple spectator models, so far no model-independent nontrivial relations have been established. In fact, by relating the two types of parton distributions to the fully unintegrated, off-diagonal quark-quark correlator for a spin-1/2 hadron, we argue that none of the nontrivial relations can be promoted to a model-independent status.

On the Structure of Actinotrocha considered in relation to the suggested Chordate Affinities of Phoronis

1897 ◽  
Vol 21 ◽  
pp. 129-136 ◽  
Author(s):  
A. T. Masterman
Keyword(s):  
Nervous System ◽  
Present Knowledge ◽  
The Other ◽  
Critical Examination ◽  
Preliminary Note ◽  
Skeletal Structures ◽  
Other Hand

Some little time ago a preliminary note upon Phoronis was read before the Eoyal Society, and therein it was stated that a study of the anatomy of this group had led one to believe that its nearest phyletic allies were to be found in the Hemichorda, a group comprising a few species with primitive chordate characters.In attempting to class Phoronis with these, an important difficulty presented itself. It has been usual to define the Chordata as having three essential characters in common, either temporarily in ontogeny or permanently throughout life, i.e., a dorsal nervous system, paired gill-slits, and a notochord.With regard to these features, there can be no doubt that the nervous system of Phoronis is dorsal in position, and its arrangement is exactly comparable to that of Balanoglossus; but, on the other hand, there are no gill-slits in the adult Phoronis, and the notochord is as certainly absent.In the case of the gill-slits, we find upon critical examination that they are extremely variable in extent of number and position in the different Chordata, and in one species, Rhabdopleura, they are, according to present knowledge, entirely absent. For these reasons it is well not to insist on the presence of gill-slits as an essential character. With respect to the notochord a different condition prevails-the hypoblastic origin and vacuolated character of this organ mark it out from all other skeletal structures, and it figures more or less prominently in all the Chordata.

scholarly journals The function of PROTOPORPHYRINOGEN IX OXIDASE in chlorophyll biosynthesis requires oxidised plastoquinone in Chlamydomonas reinhardtii

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Pawel Brzezowski ◽  
Brigitte Ksas ◽  
Michel Havaux ◽  
Bernhard Grimm ◽  
Marie Chazaux ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Chlorophyll Biosynthesis

Biosynthesis Of Gallotannins. ß-Glucogallin-Dependent Galloylation Of 1,6-Digailoylglucose To 1,2,6-Trigalloylglucose

1991 ◽  
Vol 46 (5-6) ◽  
pp. 389-394 ◽  
Author(s):  
Georg G. Gross ◽  
Klaus Denzel
Keyword(s):  
Molecular Weight ◽  
Enzymatic Reaction ◽  
Relative Activity ◽  
The Other ◽  
Ph Optimum ◽  
Acceptor Substrate ◽  
Free Glucose ◽  
Rhus Typhina ◽  
Acyl Donors ◽  
Stimulation Of

An enzyme from leaves of sumach (Rhus typhina) was partially purified that catalyzes the β-glucogallin (l-O-galloylglucose)-dependent galloylation of 1,6-digalloylglucose, thus forming 1,2,6-trigalloylglucose and free glucose. This acyltransferase had a molecular weight of ca. 750,000 and a pH optimum at 5.0-5 .5. Besides β-glucogallin (Km = 3.9 mM ) , also related 1-O-phenylcarboxylglucoses acted as acyl donors. On the other hand, the acceptor substrate, 1,6-digalloylglucose (Km = 0.9 mM ) , could only be replaced by 1,6-diprotocatechuoylglucose (relative activity 46%); however, also tri-, tetra-, and pentagalloylglucoses were galloylated. A pronounced stimulation of the enzymatic reaction was observed upon addition of penta- or hexagalloylglucose into the assay mixtures. The systematic name “ β-glucogallin: 1,6-di-O-galloylglucose 2-O-galloyltransferase” (EC 2.3.1. - ) is proposed for the enzyme

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