Why don't plants have diabetes? Systems for scavenging reactive carbonyls in photosynthetic organisms

2014 ◽  
Vol 42 (2) ◽  
pp. 543-547 ◽  
Author(s):  
Ginga Shimakawa ◽  
Mayumi Suzuki ◽  
Eriko Yamamoto ◽  
Ryota Saito ◽  
Tatsuya Iwamoto ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Higher Plants ◽  
Sugar Metabolism ◽  
Toxic Effects ◽  
Medium Chain ◽  
Photosynthetic Organisms

In the present paper, we review the toxicity of sugar- and lipid-derived RCs (reactive carbonyls) and the RC-scavenging systems observed in photosynthetic organisms. Similar to heterotrophs, photosynthetic organisms are exposed to the danger of RCs produced in sugar metabolism during both respiration and photosynthesis. RCs such as methylglyoxal and acrolein have toxic effects on the photosynthetic activity of higher plants and cyanobacteria. These toxic effects are assumed to occur uniquely in photosynthetic organisms, suggesting that RC-scavenging systems are essential for their survival. The aldo–keto reductase and the glyoxalase systems mainly scavenge sugar-derived RCs in higher plants and cyanobacteria. 2-Alkenal reductase and alkenal/alkenone reductase catalyse the reduction of lipid-derived RCs in higher plants. In cyanobacteria, medium-chain dehydrogenases/reductases are the main scavengers of lipid-derived RCs.

DNA microarrays for studies of higher plants and other photosynthetic organisms

1999 ◽  
Vol 4 (1) ◽  
pp. 38-41 ◽  
Author(s):  
David M. Kehoe ◽  
Per Villand ◽  
Shauna Somerville
Keyword(s):  
Dna Microarrays ◽  
Higher Plants ◽  
Photosynthetic Organisms

scholarly journals High-speed Blown Air as a Source of Thigmic Stress: Effect of Physiology and Yield of Red Raspberry

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 781B-781
Author(s):  
Todd A. Kostman ◽  
J. Scott Cameron ◽  
Chuhe Chen ◽  
Stephen F. Klauer
Keyword(s):  
Mechanical Stress ◽  
High Speed ◽  
Photosynthetic Activity ◽  
Secondary Xylem ◽  
Higher Plants ◽  
Field Trials ◽  
Stress Effect ◽  
Red Raspberry ◽  
Callose Deposition ◽  
Cross Sectional

The effect of mechanical stress from sources such as wind on the physiology of higher plants has been documented in many species. Some of these reported changes, such as decreased photosynthetic activity, are not well-documented and bear closer examination. Mechanical stress has been reported to decrease the productivity of some crop plants. In both field and greenhouse trials, high-speed blown air was used as a thigmic stress for the temporary, nonchemical suppression of primocane growth in red raspberry. Field trials with the cultivar Meeker in 1993–94 have shown that high-speed blown air can be used to adequately control primocane height for mechanical harvest, while increasing yield through greater numbers of fruit per cane. In both field and greenhouse experiments, photosynthetic activity or red raspberry leaves was not affected by 273 km/h of wind applied twice daily, 5 days per week. Anatomical analysis demonstrated changes in the cross-sectional anatomy of mechanically stressed canes. Stressed canes had increased callose deposition and greater numbers of secondary xylem cells.

scholarly journals A unique ferredoxin acts as a player in the low-iron response of photosynthetic organisms

2018 ◽  
Vol 115 (51) ◽  
pp. E12111-E12120 ◽  
Author(s):  
Michael Schorsch ◽  
Manuela Kramer ◽  
Tatjana Goss ◽  
Marion Eisenhut ◽  
Nigel Robinson ◽  
...  
Keyword(s):  
Protein Function ◽  
Posttranscriptional Regulation ◽  
Iron Homeostasis ◽  
Higher Plants ◽  
Iron Status ◽  
Photosynthetic Electron Transport ◽  
Protein Levels ◽  
Photosynthetic Organisms ◽  
Chlorophyll Accumulation ◽  
Iron Concentrations

Iron chronically limits aquatic photosynthesis, especially in marine environments, and the correct perception and maintenance of iron homeostasis in photosynthetic bacteria, including cyanobacteria, is therefore of global significance. Multiple adaptive mechanisms, responsive promoters, and posttranscriptional regulators have been identified, which allow cyanobacteria to respond to changing iron concentrations. However, many factors remain unclear, in particular, how iron status is perceived within the cell. Here we describe a cyanobacterial ferredoxin (Fed2), with a unique C-terminal extension, that acts as a player in iron perception. Fed2 homologs are highly conserved in photosynthetic organisms from cyanobacteria to higher plants, and, although they belong to the plant type ferredoxin family of [2Fe-2S] photosynthetic electron carriers, they are not involved in photosynthetic electron transport. As deletion offed2appears lethal, we developed a C-terminal truncation system to attenuate protein function. Disturbed Fed2 function resulted in decreased chlorophyll accumulation, and this was exaggerated in iron-depleted medium, where different truncations led to either exaggerated or weaker responses to low iron. Despite this, iron concentrations remained the same, or were elevated in all truncation mutants. Further analysis established that, when Fed2 function was perturbed, the classical iron limitation marker IsiA failed to accumulate at transcript and protein levels. By contrast, abundance of IsiB, which shares an operon withisiA, was unaffected by loss of Fed2 function, pinpointing the site of Fed2 action in iron perception to the level of posttranscriptional regulation.

Sugar Metabolism and Compartmentation

1991 ◽  
Vol 18 (3) ◽  
pp. 227 ◽  
Author(s):  
JS Hawker ◽  
CF Jenner ◽  
CM Niemietz
Keyword(s):  
Higher Plants ◽  
Sugar Metabolism ◽  
Current Interest ◽  
Sucrose Transport ◽  
Inorganic Pyrophosphate ◽  
General Picture ◽  
Transport Control

A brief general picture of areas of current interest in the field of sugar metabolism and compartmentation in higher plants is presented. The control of partitioning of carbohydrate between sucrose and starch in leaves (source), the breakdown and utilisation of sucrose in sinks, and the storage of sugars and starch in sinks is described. Pathways of sucrose transport (excluding plasmalemma transport), control of sugar metabolism by fructose 2,6-bisphosphate, the role and source of inorganic pyrophosphate in sugar metabolism and the transport of carbon across the amyloplast envelope receive special attention.

scholarly journals Exploration of Autophagy Families in Legumes and Dissection of the ATG18 Family with a Special Focus on Phaseolus vulgaris

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2619
Author(s):  
Elsa-Herminia Quezada-Rodríguez ◽  
Homero Gómez-Velasco ◽  
Manoj-Kumar Arthikala ◽  
Miguel Lara ◽  
Antonio Hernández-López ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Higher Plants ◽  
Large Family ◽  
Lipid Binding ◽  
Model Organisms ◽  
Special Focus ◽  
Scaling Analysis ◽  
Protein Motifs ◽  
Photosynthetic Organisms ◽  
Atg Genes

Macroautophagy/autophagy is a fundamental catabolic pathway that maintains cellular homeostasis in eukaryotic cells by forming double-membrane-bound vesicles named autophagosomes. The autophagy family genes remain largely unexplored except in some model organisms. Legumes are a large family of economically important crops, and knowledge of their important cellular processes is essential. Here, to first address the knowledge gaps, we identified 17 ATG families in Phaseolus vulgaris, Medicago truncatula and Glycine max based on Arabidopsis sequences and elucidated their phylogenetic relationships. Second, we dissected ATG18 in subfamilies from early plant lineages, chlorophytes to higher plants, legumes, which included a total of 27 photosynthetic organisms. Third, we focused on the ATG18 family in P. vulgaris to understand the protein structure and developed a 3D model for PvATG18b. Our results identified ATG homologs in the chosen legumes and differential expression data revealed the nitrate-responsive nature of ATG genes. A multidimensional scaling analysis of 280 protein sequences from 27 photosynthetic organisms classified ATG18 homologs into three subfamilies that were not based on the BCAS3 domain alone. The domain structure, protein motifs (FRRG) and the stable folding conformation structure of PvATG18b revealing the possible lipid-binding sites and transmembrane helices led us to propose PvATG18b as the functional homolog of AtATG18b. The findings of this study contribute to an in-depth understanding of the autophagy process in legumes and improve our knowledge of ATG18 subfamilies.

scholarly journals Biosynthesis Pathways of Vitamin E and Its Derivatives in Plants

2021 ◽  
Author(s):  
Makhlouf Chaalal ◽  
Siham Ydjedd
Keyword(s):  
Vitamin E ◽  
Higher Plants ◽  
Aromatic Amino Acids ◽  
Biosynthetic Pathways ◽  
Edible Plant ◽  
Methylerythritol Phosphate Pathway ◽  
Methylerythritol Phosphate ◽  
Photosynthetic Organisms ◽  
And Function

Naturally occurring vitamin E, comprised of four forms each of tocopherols and tocotrienols, are synthesized solely by photosynthetic organisms and function primarily as antioxidants. The structural motifs of the vitamin E family and specifically the chroman moiety, are amenable to various modifications in order to improve their bioactivities towards numerous therapeutic targets. Tocopherols are lipophilic antioxidants and together with tocotrienols belong to the vitamin-E family. These lipid-soluble compounds are potent antioxidants that protect polyunsaturated fatty acids from lipid peroxidation. Biosynthetic pathways of plants producing a diverse array of natural products that are important for plant function, agriculture, and human nutrition. Edible plant-derived products, notably seed oils, are the main sources of vitamin E in the human diet. The biosynthesis of tocopherols takes place mainly in plastids of higher plants from precursors derived from two metabolic pathways: homogentisic acid, an intermediate of degradation of aromatic amino acids, and phytyldiphosphate, which arises from methylerythritol phosphate pathway. Tocopherols and tocotrienols play an important roles in the oxidative stability of vegetable oils and in the nutritional quality of crop plants for human and livestock diets. Here, we review major biosynthetic pathways, including common precursors and competitive pathways of the vitamin E and its derivatives in plants.

scholarly journals The synthesis of acetylcholine by plants

1981 ◽  
Vol 194 (1) ◽  
pp. 361-364 ◽  
Author(s):  
B N Smallman ◽  
A Maneckjee
Keyword(s):  
Pisum Sativum ◽  
Green Algae ◽  
Choline Acetyltransferase ◽  
Spinacia Oleracea ◽  
Higher Plants ◽  
Urtica Dioica ◽  
The Other ◽  
Affinity Column ◽  
Blue Green Algae ◽  
Photosynthetic Organisms

Choline acetyltransferase was demonstrated in nettles (Urtica dioica), peas (Pisum sativum), spinach (Spinacia oleracea), sunflower (Helianthus annuus) and blue–green algae by using a Sepharose–CoASH affinity column. The column effected a 1500-fold purification of the enzyme from nettle homogenates and was required for demonstrating activity in the other higher plants. Demonstration of the enzyme in blue-green algae suggests that acetylcholine was a biochemical necessity in the earliest photosynthetic organisms.

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