scholarly journals Synthetic biogenesis of chromoplasts from leaf chloroplasts

2019 ◽  
Author(s):  
Briardo Llorente ◽  
Salvador Torres-Montilla ◽  
Luca Morelli ◽  
Igor Florez-Sarasa ◽  
Miguel Ezquerro ◽  
...  
Keyword(s):  
Nutritional Value ◽  
Morphological Changes ◽  
Nuclear Gene ◽  
Beta Carotene ◽  
Second Stage ◽  
Nuclear Gene Expression ◽  
Absolute Requirement ◽  
Plastid Morphology ◽  
Threshold Switch ◽  
Switch Mechanism

AbstractPlastids, the defining organelles of plant cells, undergo physiological and morphological changes to fulfill distinct biological functions. In particular, the differentiation of chloroplasts into chromoplasts results in an enhanced storage capacity for carotenoids with industrial and nutritional value such as beta-carotene (pro-vitamin A). Here, we show that synthetically inducing a burst in the production of phytoene, the first committed intermediate of the carotenoid pathway, elicits an artificial chloroplast-to-chromoplast differentiation in leaves. Phytoene overproduction initially interferes with photosynthesis, acting as a metabolic threshold switch mechanism that weakens chloroplast identity. In a second stage, phytoene conversion into downstream carotenoids is required for the differentiation of chromoplasts. Our findings reveal that lowering the photosynthetic capacity of chloroplasts and increasing the production of carotenoids are not just the consequence but an absolute requirement for chromoplast differentiation, which additionally involves a concurrent reprogramming of nuclear gene expression and plastid morphology for improved carotenoid storage.

scholarly journals Synthetic conversion of leaf chloroplasts into carotenoid-rich plastids reveals mechanistic basis of natural chromoplast development

2020 ◽  
Vol 117 (35) ◽  
pp. 21796-21803
Author(s):  
Briardo Llorente ◽  
Salvador Torres-Montilla ◽  
Luca Morelli ◽  
Igor Florez-Sarasa ◽  
José Tomás Matus ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Nuclear Gene ◽  
Beta Carotene ◽  
Second Stage ◽  
Nuclear Gene Expression ◽  
Enhanced Production ◽  
Plastid Morphology ◽  
Threshold Switch ◽  
Switch Mechanism ◽  
Mechanistic Basis

Plastids, the defining organelles of plant cells, undergo physiological and morphological changes to fulfill distinct biological functions. In particular, the differentiation of chloroplasts into chromoplasts results in an enhanced storage capacity for carotenoids with industrial and nutritional value such as beta-carotene (provitamin A). Here, we show that synthetically inducing a burst in the production of phytoene, the first committed intermediate of the carotenoid pathway, elicits an artificial chloroplast-to-chromoplast differentiation in leaves. Phytoene overproduction initially interferes with photosynthesis, acting as a metabolic threshold switch mechanism that weakens chloroplast identity. In a second stage, phytoene conversion into downstream carotenoids is required for the differentiation of chromoplasts, a process that involves a concurrent reprogramming of nuclear gene expression and plastid morphology for improved carotenoid storage. We hence demonstrate that loss of photosynthetic competence and enhanced production of carotenoids are not just consequences but requirements for chloroplasts to differentiate into chromoplasts.

scholarly journals Thioredoxin-dependent control balances the metabolic activities of tetrapyrrole biosynthesis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniel Wittmann ◽  
Neha Sinha ◽  
Bernhard Grimm
Keyword(s):  
Environmental Changes ◽  
Nuclear Gene ◽  
Tetrapyrrole Biosynthesis ◽  
Nuclear Gene Expression ◽  
Light Levels ◽  
Organ Specific ◽  
Intracellular Compartments ◽  
The Face ◽  
Metabolic Activities ◽  
The Impact

AbstractPlastids are specialized organelles found in plants, which are endowed with their own genomes, and differ in many respects from the intracellular compartments of organisms belonging to other kingdoms of life. They differentiate into diverse, plant organ-specific variants, and are perhaps the most versatile organelles known. Chloroplasts are the green plastids in the leaves and stems of plants, whose primary function is photosynthesis. In response to environmental changes, chloroplasts use several mechanisms to coordinate their photosynthetic activities with nuclear gene expression and other metabolic pathways. Here, we focus on a redox-based regulatory network composed of thioredoxins (TRX) and TRX-like proteins. Among multiple redox-controlled metabolic activities in chloroplasts, tetrapyrrole biosynthesis is particularly rich in TRX-dependent enzymes. This review summarizes the effects of plastid-localized reductants on several enzymes of this pathway, which have been shown to undergo dithiol-disulfide transitions. We describe the impact of TRX-dependent control on the activity, stability and interactions of these enzymes, and assess its contribution to the provision of adequate supplies of metabolic intermediates in the face of diurnal and more rapid and transient changes in light levels and other environmental factors.

Chloroplast Redox Control of Nuclear Gene Expression—A New Class of Plastid Signals in Interorganellar Communication

2003 ◽  
Vol 5 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Thomas Pfannschmidt ◽  
Katia Schütze ◽  
Vidal Fey ◽  
Irena Sherameti ◽  
Ralf Oelmüller
Keyword(s):  
Gene Expression ◽  
Nuclear Gene ◽  
Redox Control ◽  
New Class ◽  
Nuclear Gene Expression

scholarly journals MITOCHONDRIAL BIOGENESIS DURING DIFFERENTIATION OF ARTEMIA SALINA CYSTS

1973 ◽  
Vol 58 (3) ◽  
pp. 643-649 ◽  
Author(s):  
H. Schmitt ◽  
H. Grossfeld ◽  
U. Z. Littauer
Keyword(s):  
Cytochrome C ◽  
Cytochrome Oxidase ◽  
Cytochrome B ◽  
Mitochondrial Biogenesis ◽  
Brine Shrimp ◽  
Morphological Changes ◽  
Artemia Salina ◽  
Mitochondrial Morphology ◽  
Second Stage ◽  
Two Stages

Mitochondria isolated from cysts of Artemia salina (brine shrimp) were found to be devoid of cristae and to possess a low respiratory capability. Hydration of the cysts induces marked biochemical and morphological changes in the mitochondria. Their biogenesis proceeds in two stages. The first stage is completed within 1 h and is characterized by a rapid increase in the respiratory capability of the mitochondria, their cytochrome oxidase, cytochrome b, cytochrome c and perhaps some morphological changes. In the second stage there is an increase in the protein-synthesizing capacity of the mitochondria as well as striking changes in mitochondrial morphology leading to the formation of cristae.

scholarly journals Introns mediate post-transcriptional enhancement of nuclear gene expression in the green microalga Chlamydomonas reinhardtii

PLoS Genetics ◽  
2020 ◽  
Vol 16 (7) ◽  
pp. e1008944 ◽  
Author(s):  
Thomas Baier ◽  
Nick Jacobebbinghaus ◽  
Alexander Einhaus ◽  
Kyle J. Lauersen ◽  
Olaf Kruse
Keyword(s):  
Gene Expression ◽  
Chlamydomonas Reinhardtii ◽  
Nuclear Gene ◽  
Nuclear Gene Expression ◽  
Green Microalga

scholarly journals Updated Understanding of Cancer as a Metabolic and Telomere-Driven Disease, and Proposal for Complex Personalized Treatment, a Hypothesis

2020 ◽  
Vol 21 (18) ◽  
pp. 6521
Author(s):  
Cristian Muresanu ◽  
Siva G. Somasundaram ◽  
Sergey V. Vissarionov ◽  
Luis Fernando Torres Solis ◽  
Arturo Solís Herrera ◽  
...  
Keyword(s):  
Metabolic Disease ◽  
Dna Damage ◽  
Telomere Length ◽  
Oxidative Dna Damage ◽  
Nuclear Gene ◽  
Holistic Approach ◽  
Telomerase Activity ◽  
Metabolic Reprogramming ◽  
Intermittent Fasting ◽  
Nuclear Gene Expression

In this review, we propose a holistic approach to understanding cancer as a metabolic disease. Our search for relevant studies in medical databases concludes that cancer cells do not evolve directly from normal healthy cells. We hypothesize that aberrant DNA damage accumulates over time—avoiding the natural DNA controls that otherwise repair or replace the rapidly replicating cells. DNA damage starts to accumulate in non-replicating cells, leading to senescence and aging. DNA damage is linked with genetic and epigenetic factors, but the development of cancer is favored by telomerase activity. Evidence indicates that telomere length is affected by chronic inflammations, alterations of mitochondrial DNA, and various environmental factors. Emotional stress also influences telomere length. Chronic inflammation can cause oxidative DNA damage. Oxidative stress, in turn, can trigger mitochondrial changes, which ultimately alter nuclear gene expression. This vicious cycle has led several scientists to view cancer as a metabolic disease. We have proposed complex personalized treatments that seek to correct multiple changes simultaneously using a psychological approach to reduce chronic stress, immune checkpoint therapy with reduced doses of chemo and radiotherapy, minimal surgical intervention, if any, and mitochondrial metabolic reprogramming protocols supplemented by intermittent fasting and personalized dietary plans without interfering with the other therapies.

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