scholarly journals Photosystem Disorder Could be the Key Cause for the Formation of Albino Leaf Phenotype in Pecan

2020 ◽  
Vol 21 (17) ◽  
pp. 6137
Author(s):  
Ji-Yu Zhang ◽  
Tao Wang ◽  
Zhan-Hui Jia ◽  
Zhong-Ren Guo ◽  
Yong-Zhi Liu ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Molecular Mechanisms ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Photosynthetic Electron Transport ◽  
Chlorophyll Degradation ◽  
Pheophorbide A ◽  
Leaf Phenotype ◽  
Photosynthesis Pathway ◽  
Almost All

Pecan is one of the most famous nut species in the world. The phenotype of mutants with albino leaves was found in the process of seeding pecan, providing ideal material for the study of the molecular mechanisms leading to the chlorina phenotype in plants. Both chlorophyll a and chlorophyll b contents in albino leaves (ALs) were significantly lower than those in green leaves (GLs). A total of 5171 differentially expression genes (DEGs) were identified in the comparison of ALs vs. GLs using high-throughput transcriptome sequencing; 2216 DEGs (42.85%) were upregulated and 2955 DEGs (57.15%) were downregulated. The expressions of genes related to chlorophyll biosynthesis (HEMA1, encoding glutamyl-tRNA reductase; ChlH, encoding Mg-protoporphyrin IX chelatase (Mg-chelatase) H subunit; CRD, encoding Mg-protoporphyrin IX monomethylester cyclase; POR, encoding protochlorophyllide reductase) in ALs were significantly lower than those in GLs. However, the expressions of genes related to chlorophyll degradation (PAO, encoding pheophorbide a oxygenase) in ALs were significantly higher than those in GLs, indicating that disturbance of chlorophyll a biosynthesis and intensification of chlorophyll degradation lead to the absence of chlorophyll in ALs of pecan. A total of 72 DEGs associated with photosynthesis pathway were identified in ALs compared to GLs, including photosystem I (15), photosystem II (19), cytochrome b6-f complex (3), photosynthetic electron transport (6), F-type ATPase (7), and photosynthesis-antenna proteins (22). Moreover, almost all the genes (68) mapped in the photosynthesis pathway showed decreased expression in ALs compared to GLs, declaring that the photosynthetic system embedded within the thylakoid membrane of chloroplast was disturbed in ALs of pecan. This study provides a theoretical basis for elucidating the molecular mechanism underlying the phenotype of chlorina seedlings of pecan.

Chlorophyll a biosynthesis

1976 ◽  
Vol 273 (924) ◽  
pp. 207-225 ◽  
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Chlorophyll Synthesis ◽  
Synthesis Reaction ◽  
Etiolated Leaves ◽  
Regulatory Aspects ◽  
Vinyl Group ◽  
Chlorophyll A Biosynthesis ◽  
Monomethyl Ester

Protoporphyrin IX is believed to be an intermediate common to both haem and chlorophyll biosynthesis. The pathway specific to chlorophyll starts with magnesium protoporphyrin and its monomethyl ester. Two routes have been proposed for conversion of the latter compound to protochlorophyllide: A, formation of the isocyclic ring followed by reduction of the 4-vinyl group, or B, reduction of the 4-vinyl group followed by formation of the isocyclic ring. Membranes prepared from isolated barley etioplasts are found to convert magnesium 2,4-divinylphaeoporphyrin a 5 monomethyl ester to chlorophyllide a at a rate equal to that of chlorophyll synthesis in intact leaves: this result supports route A. NADPH is necessary to maintain the two successive reductive steps: reduction of the 4-vinyl group and then the photoreduction of ring IV to yield chlorophyllide. The prohaem content of etiolated leaves does not increase during the phase of active chlorophyll synthesis although evidence is presented that suggests that the ALA synthesis reaction that regulates chlorophyll synthesis is common to both pathways. This and other regulatory aspects are discussed.

Studies on the biosynthesis of the Chlorobium chlorophylls

1976 ◽  
Vol 273 (924) ◽  
pp. 255-276 ◽  
Keyword(s):  
Methyl Ester ◽  
Chlorophyll A ◽  
Alkyl Group ◽  
Biosynthetic Pathway ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Methyl Groups ◽  
Chemical Transformations ◽  
The Novel ◽  
Feeding Experiments

The Chlorobium chlorophylls (660) from Chloropseudomonas ethylicum are shown by 13 C n.m.r. spectroscopy and certain chemical transformations to be meso -methylated at the δ-position. Earlier work, which proposed that the meso -alkyl group was present at the α or β positions, is shown to be experimentally correct, but incorrectly interpreted. On the basis of 14 C and 13 C feeding experiments, the novel methyl groups in the (660) chlorophylls are shown to be derived from methionine in all cases. For most of the homologous mixture of (660) chlorophylls, the branch point from the biosynthetic pathway to chlorophyll a appears to lie between uroporphyrinogen III and coproporphyrinogen III; earlier workers had suggested that Chlorobium chlorophyll biosynthesis proceeded through magnesium protoporphyrin IX mono-methyl ester and possibly also via bacteriochlorophyll a or one of its immediate precursors. Evidence against this proposal, and a working hypothesis explaining feeding results, is presented. On the basis of this hypothesis, proposals for the structures of certain fractions of the (660) chlorophylls which are currently in dispute, are presented.

scholarly journals Transcriptome and proteome analysis suggest enhanced photosynthesis in tetraploid Liriodendron sino-americanum

2021 ◽  
Author(s):  
Tingting Chen ◽  
Yu Sheng ◽  
Zhaodong Hao ◽  
Xiaofei Long ◽  
Fangfang Fu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Proteome Analysis ◽  
Tree Height ◽  
Photosynthetic Electron Transport ◽  
Industrial Applications ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein ◽  
Photosynthesis Genes ◽  
Underlying Mechanisms

Abstract Polyploidy generally provides an advantage in phenotypic variation and growth vigor. However, the underlying mechanisms remain poorly understood. The tetraploid L. sino-americanum exhibits altered morphology compared to its diploid counterpart, including larger, thicker and deeper green leaves, bigger stomata, thicker stems and increased tree height. Such characteristics can be useful in ornamental and industrial applications. To elucidate the molecular mechanisms behind this variation, we performed a comparative transcriptome and proteome analysis. Our transcriptome data indicated that some photosynthesis genes and pathways were differentially altered and enriched in tetraploid L. sino-americanum, mainly related to F-type ATPase, the cytochrome b6/f complex, photosynthetic electron transport, the light harvesting chlorophyll protein complexes, photosystem I and II. Most of the differentially expressed proteins we could identify are also involved in photosynthesis. Our physiological results showed that tetraploids have an enhanced photosynthetic capacity, concomitant with great levels of sugar and starch in leaves. This suggests that tetraploid L. sino-americanum might experience comprehensive transcriptome reprogramming of genes related to photosynthesis. This study has especially emphasized molecular changes involved in photosynthesis that accompany polyploidy, and provides a possible explanation for the altered phenotype of polyploidy plants in comparison to their diploid form.

scholarly journals The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

2021 ◽  
Vol 22 (5) ◽  
pp. 2472
Author(s):  
Carl Randall Harrell ◽  
Valentin Djonov ◽  
Vladislav Volarevic
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Immune Cells ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Multipotent Stem Cells ◽  
Tissue Repair And Regeneration ◽  
Almost All ◽  
And Function

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

scholarly journals Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Chain ◽  
Plant Density ◽  
Photosynthetic Electron Transport ◽  
Planting Density ◽  
Strong Impact ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.

Mutation in Mg-Protoporphyrin IX Monomethyl Ester Cyclase Causes Yellow and Spotted Leaf Phenotype in Rice

2019 ◽  
Vol 37 (4) ◽  
pp. 253-264 ◽  
Author(s):  
Chun Li ◽  
Furong Ma ◽  
Renjun Jiao ◽  
Congping Chen ◽  
Qian Wang ◽  
...  
Keyword(s):  
Protoporphyrin Ix ◽  
Leaf Phenotype ◽  
Monomethyl Ester

scholarly journals Analisis Kandungan Klorofil Pada Anak Daun Tanaman Kelapa (Analysis of Chlorophyll Content in Children Leaves of Coconut Plants)

2019 ◽  
Vol 9 (2) ◽  
pp. 76
Author(s):  
Muhammad Tawary ◽  
Julius Pontoh ◽  
Lydia Momuat
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Economic Value ◽  
Economic Benefits ◽  
Chlorophyll B ◽  
Solvent Extraction Method ◽  
Chlorophyll A And B ◽  
The Right ◽  
Almost All ◽  
Chlorophyll A Content

Analisis Kandungan Klorofil Pada Anak Daun Tanaman Kelapa (Analysis of Chlorophyll Content in Children Leaves of Coconut Plants) Muhammad Tawary1*), Julius Pontoh1), Lydia I.Momuat1)1)Jurusan Kimia, FMIPA UNSRAT Manado*Email korespondensi: [email protected] Diterima 7 Juli 2019, diterima untuk dipublikasi 10 Agustus 2019 Abstrak Tanaman kelapa banyak dibudidayakan sebagai tanaman pertanian. Tanaman kelapa memiliki nilai ekonomi yang tinggi karena hampir semua bagian tanaman kelapa memiliki manfaat ekonomis. Penelitian bertujuan untuk  mengembangkan metode analisis klorofil pada daun dan menentukan bagian anak daun yang memiliki kandungan klorofil tertinggi. Analisis kandungan klorofil dilakukan dengan metode ektraksi pelarut yang absorbansinya dibaca pada spektrofotometer UV-Vis. Kandungan klorofil a dalam daun bervariasi pada setiap bagian anak daun tanaman kelapa. Kandungan klorofil a pada posisi tengah anak daun kelapa (763.19 µmol/m2) dan kandungan klorofil b (196.22 µmol/m2). Kandungan klorofil a dan b pada setiap bagian anak daun dan posisi kanan dan kiri anak daun memiliki nilai yang relatif sama.Kata kunci: Kelapa, klorofil a, klorofil b Abstract Many coconut plants are cultivated as agricultural crops. Coconut plants have high economic value because almost all parts of coconut plants have economic benefits. The study aims to develop a method of chlorophyll analysis on leaves and determine the part of leaflets which have the highest chlorophyll content. Analysis of chlorophyll content was carried out by a solvent extraction method in which the absorbance was read in a UV-Vis spectrophotometer. The content of chlorophyll a in leaves varies with each part of the leaves of the coconut plant. Chlorophyll a content in the middle position of coconut leaf child (763.19 µmol / m2) and chlorophyll b content (196.22 µmol / m2). The content of chlorophyll a and b in each part of the leaf child and the right and left positions of the leaves have relatively the same value.Keywords: Coconut, Chlorophyll a, Chlorophyll b

scholarly journals The GTEx Consortium atlas of genetic regulatory effects across human tissues

Science ◽  
2020 ◽  
Vol 369 (6509) ◽  
pp. 1318-1330 ◽  
Author(s):  
Keyword(s):  
Complex Traits ◽  
Molecular Mechanisms ◽  
Tissue Expression ◽  
Genetic Effects ◽  
Regulatory Mechanisms ◽  
Human Tissues ◽  
Genetic Associations ◽  
Key Factor ◽  
Regulatory Effects ◽  
Almost All

The Genotype-Tissue Expression (GTEx) project was established to characterize genetic effects on the transcriptome across human tissues and to link these regulatory mechanisms to trait and disease associations. Here, we present analyses of the version 8 data, examining 15,201 RNA-sequencing samples from 49 tissues of 838 postmortem donors. We comprehensively characterize genetic associations for gene expression and splicing in cis and trans, showing that regulatory associations are found for almost all genes, and describe the underlying molecular mechanisms and their contribution to allelic heterogeneity and pleiotropy of complex traits. Leveraging the large diversity of tissues, we provide insights into the tissue specificity of genetic effects and show that cell type composition is a key factor in understanding gene regulatory mechanisms in human tissues.

Reduction of the Formyl Group of Zinc Pheophorbide b in vitro and in vivo: a Model for the Chlorophyll b to a Transformation

1996 ◽  
Vol 51 (3-4) ◽  
pp. 185-194 ◽  
Author(s):  
Verena Scheumann ◽  
Michael Helfrich ◽  
Siegrid Schoch ◽  
Wolfhart Rüdiger
Keyword(s):  
Nmr Spectroscopy ◽  
Chlorophyll A ◽  
Chemical Reduction ◽  
Chlorophyll B ◽  
Formyl Group ◽  
Pheophorbide A ◽  
Pheophytin A ◽  
H Nmr

Abstract The chemical reduction of the formyl group of pheophorbide b with sodium cyanoborohy­ dride in methanol leads to 71-methoxy-and 71-hydroxy-pheophorbide a. The same reaction with zinc pheophorbide b yields in addition zinc pheophorbide a. This was characterized by mass and 1H -NMR spectroscopy. Infiltration of zinc pheophorbides a and b and of zinc 71-hydroxy-pheophorbide a into etiolated oat leaves yielded phytylated products. The best yield in the esterification was obtained with 71-hydroxy-pheophorbide a. Analysis of the products revealed the formation of zinc pheophytin a from all infiltrated compounds. The significance for the transformation of chlorophyll b into chlorophyll a is discussed.

Gene Trap, Gene Knockout, Gene Knock-In, and Transgenics in Vascular Development

1999 ◽  
Vol 82 (08) ◽  
pp. 865-869 ◽  
Author(s):  
Thomas Sato
Keyword(s):  
Animal Models ◽  
Molecular Mechanisms ◽  
Vascular System ◽  
System Development ◽  
Gene Knockout ◽  
Vascular Development ◽  
Branching Morphogenesis ◽  
Abnormal Development ◽  
Organ Systems ◽  
Almost All

IntroductionThe vascular system is one of the first organ systems to develop in our bodies. Normal development and maturation of the physiological functions of almost all of the other organs are critically dependent on the accurate and tightly controlled establishment of the vascular system. Our understanding of the mechanisms underlying the formation of the vascular system during development is still in its infancy. With further understanding of these mechanisms, we may eventually be able to correct the abnormal development and the malfunctioning of many organs by therapeutically modulating the morphology and/or physiological function of the vascular system.Our further understanding of the vascular development can, in part, be achieved by discovering the molecules that play critical roles in this process. We could also achieve this goal by learning more about the functions of previously identified molecules in the vascular system. Discovery of new processes underlying the development of the vascular system will also contribute to further understanding of these molecular mechanisms.Recent advances, using the whole genome approach, have resulted in a flood of new information. This trend will continue, and fortunately, a number of molecular reagents will become available. Therefore, the field will likely experience an exponential growth in terms of novel biological insights and discovering the mechanisms of vascular system development.Occasionally, reductionistic approaches help to systematically address a number of biological problems, including the problems associated with vascular system development. One such approach is to choose an organism that allows us to systematically address these biological questions. The choice of animal models that are well-suited for the study of a particular question has led to a large number of discoveries. To address questions in vascular system development, current research has focused on animal models, including fish, frog, bird, and mouse, and also studies involving humans. It is also worthwhile to note that the branching morphogenesis of the fly trachea system has been utilized to address fundamental questions of vascular morphogenesis.This chapter will summarize the genomic manipulation of the murine vascular system to address questions regarding vascular development. In addition, the advances that have been made in this field using such methods will be summarized.

Sign in / Sign up

Export Citation Format

Share Document