scholarly journals In Vitro Enzymatic Activity Assays Implicate the Existence of the Chlorophyll Cycle in Chlorophyll b-Containing Cyanobacteria

2019 ◽  
Vol 60 (12) ◽  
pp. 2672-2683 ◽  
Author(s):  
HyunSeok Lim ◽  
Ayumi Tanaka ◽  
Ryouichi Tanaka ◽  
Hisashi Ito

Abstract In plants, chlorophyll (Chl) a and b are interconvertible by the action of three enzymes—chlorophyllide a oxygenase, Chl b reductase (CBR) and 7-hydroxymethyl chlorophyll a reductase (HCAR). These reactions are collectively referred to as the Chl cycle. In plants, this cyclic pathway ubiquitously exists and plays essential roles in acclimation to different light conditions at various developmental stages. By contrast, only a limited number of cyanobacteria species produce Chl b, and these include Prochlorococcus, Prochloron, Prochlorothrix and Acaryochloris. In this study, we investigated a possible existence of the Chl cycle in Chl b synthesizing cyanobacteria by testing in vitro enzymatic activities of CBR and HCAR homologs from Prochlorothrix hollandica and Acaryochloris RCC1774. All of these proteins show respective CBR and HCAR activity in vitro, indicating that both cyanobacteria possess the potential to complete the Chl cycle. It is also found that CBR and HCAR orthologs are distributed only in the Chl b-containing cyanobacteria that habitat shallow seas or freshwater, where light conditions change dynamically, whereas they are not found in Prochlorococcus species that usually habitat environments with fixed lighting. Taken together, our results implicate a possibility that the Chl cycle functions for light acclimation in Chl b-containing cyanobacteria.

1996 ◽  
Vol 51 (3-4) ◽  
pp. 185-194 ◽  
Author(s):  
Verena Scheumann ◽  
Michael Helfrich ◽  
Siegrid Schoch ◽  
Wolfhart Rüdiger

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.


Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 46
Author(s):  
Paweł Kondzior ◽  
Damian Tyniecki ◽  
Andrzej Butarewicz

The purpose of this paper is to determine the influence of color temperature of Light Emitting Diode (LED) diodes and illumination intensity on the content of photosynthetic pigments of chlorophyll a, chlorophyll b and carotenoids in Chlorella vulgaris algae cells. Choosing the right color temperature and intensity of illumination can favorably affect the growth of algae. In particular, it can contribute to the efficiency of the photosynthesis process and the amount of produced biomass from Chlorella vulgaris algae. In the spectrophotometric studies, the highest content of chlorophyll a, chlorophyll b and carotenoids was found in cultures illuminated with very cold white light (8500 K) with an intensity of 500 μmol/m2s. The highest measured content of chlorophyll a (Chl a) pigments was 48.29 mg/L, Chl b pigment was 23.25 mg/L and carotenoids pigment was 12.65 mg/L; the smallest content of pigments for Chl a (11.48 mg/L), Chl b (4.69 mg/L) and carotenoids (3.03 mg/L) was found in the sample illuminated with warm white light (3200 K) with an intensity of 50 μmol/m2s. The highest amount of dry organic matter amounting to 2.0 g/L was found in a sample illuminated with warm white light (3200 K) with an intensity of 250 μmol/m2s, then 1.91 g dry organic mass (DOM)/L for very cold white light with an intensity of 250 μmol/m2s, and 1.48 g DOM/L for very cold white light with an intensity of 50 μmol/m2s. The obtained results show that a higher content of photosynthetic pigments does not directly affect the increase of the amount of dry organic matter.


2014 ◽  
Vol 6 (3) ◽  
pp. 331-334
Author(s):  
Sali Ali ALIU ◽  
Imer RUSINOVCI ◽  
Shukri FETAHU ◽  
Bekim GASHI

Genetic diversity analysis of common bean populations is useful for breeding programs, as it helps to select genetic material to be used for further crossings. Twenty (20) common bean populations were analyzed using qualitative traits, chlorophyll “a” (Chl ‘a’), chlorophyll “b” (Chl ‘b’), total chlorophyll “a+b” (Total Chl) and carotenoides. The design of the experiment was conducted with leaves of common bean collected from different regions of Kosovo. The experiment was completely randomly with four repetitions. Pigments were extracted by grinding 80-100 mg freshly sampled leaves in 80% (v/v) acetone/water containing MgCO3, at room temperature, preserved in the dark for 24 hours. Concentration of chlorophyll and carotenoid content was measured by spectrophotometer using absorbance recorded at 663 nm, 644 nm and 452.3 nm for maximum absorption of Chl ‘a’, Chl ‘b’, and carotenoids respectively. According to our data the differences between populations for Chl ‘a’, and Chl ‘b’ was significantly higher at level of probability LSDp=0.01. The average values for Chl ‘a’, was 1.67 mg.g-1, while for Chl‘b’was 0.74 mg.g-1. In addition, the results for carotenoids content between populations were with high differences.


Author(s):  
Nevzat Sevgin

Background: Prunus microcarpa C.A. Mey. subsp. Tortusa (MK), a wild deciduous plant species, is native to Caucasus and West Asia and grows in a dry temperate climate zone. The plant is mainly used to obtain a dark greyish green dye from its leaves and it has an economic value due to ornamental characteristics. Therefore, this study aimed to determine the appropriate Polyethylene Glycol 8000 (PEG) doses for early detection of drought resistance using MK, SL-64, Garnem, Pixy and Gis-6 rootstocks.Methods: The microshoots of each rootstock were planted at the end of the fourth subculture in Magenta GA7 vessels containing NRM medium. The medium contained 1.0 mg L-1 BA + 0.01 mg L-1 IBA supplemented with 30 g L-1 sucrose, gelled with 5.5 g L-1 agar and 0, 2, 3 and 4% PEG doses (four treatments). The cultures were kept at 23±2 °C temperature under 16 h light (80 μmol m-2 s-1) and 8 h dark photoperiod.Result: The highest number of shoots was recorded in control treatment for MK rootstock (2.81 shoots plant-1) and in 4% PEG treatment for Gis-6 rootstock (2.81 shoots plant-1). Mean chlorophyll a (10.66 mg/f.w) and chlorophyll b (3.63 mg/f.w) contents in the control treatment were lower compared to the mean chlorophyll a (2.03 mg/f.w) and chlorophyll b (1.15 mg/f.w) contents of plants grown in PEG 4% dose. Prunus microcarpa genotypes of Turkey origin tested in this study could be used as potential rootstocks in arid and semi-arid region as safe as the other standard rootstocks tested.


1988 ◽  
Vol 43 (7-8) ◽  
pp. 515-518 ◽  
Author(s):  
M. Senge ◽  
A. Struck ◽  
D. Dörnemann ◽  
H. Scheer ◽  
H. Senger

Chlorophyll a is hydroxylated quantitatively in the 132-position, when chromatographed on silica gel thin-layer plates. This was shown by using HPLC as a non-destructive method für analyzing photosynthetic pigments. The hydroxy-group of Chl RC I, a 132-hydroxy-20-chloro-chl a. described by Dörnemann and Senger (1986) and Scheer et al. (1986), is shown to be artificially introduced during the purification procedure by TLC.


1977 ◽  
Vol 28 (6) ◽  
pp. 673 ◽  
Author(s):  
LV Thinh ◽  
DJ Griffiths

The microscopic algae contained within the cloacal cavity of the ascidian Diplosoma virens have a high photosynthetic capacity [up to 5.3 �gC (�g chl a)-1 h-1], giving thecolony a high photosynthesis: respiration ratio (maximum 8.0-8 5). Photosynthesis is saturated at a quantum flux density of 120 × 1015 quanta cm-2 s-1 (400-700 nm) and occurs at its maximum at temperatures between 30 and 35� C. The photosynthetic capacity is inhibited by chloramphenicol but not by cycloheximide. This is interpreted as indicating an affinity of these algae with the prokaryotes rather than the Chlorophyta, in spite of their possession of chlorophyll b (chlorophyll a : b ratio = 6.0) as an accessory pigment. In this and other respects the algae resemble those (Prochloron) described from other didemnid ascidians. Use of a buffered extraction medium has allowed separation from the animal tissue of photosynthetically active algal cells.


2021 ◽  
Vol 118 (36) ◽  
pp. e2100657118
Author(s):  
Dayna C. Patterson ◽  
Myrrh Perez Ruiz ◽  
Hyerin Yoon ◽  
Johnnie A. Walker ◽  
Jean-Paul Armache ◽  
...  

Cyclic dimeric guanosine monophosphate (c-di-GMP) serves as a second messenger that modulates bacterial cellular processes, including biofilm formation. While proteins containing both c-di-GMP synthesizing (GGDEF) and c-di-GMP hydrolyzing (EAL) domains are widely predicted in bacterial genomes, it is poorly understood how domains with opposing enzymatic activity are regulated within a single polypeptide. Herein, we report the characterization of a globin-coupled sensor protein (GCS) from Paenibacillus dendritiformis (DcpG) with bifunctional c-di-GMP enzymatic activity. DcpG contains a regulatory sensor globin domain linked to diguanylate cyclase (GGDEF) and phosphodiesterase (EAL) domains that are differentially regulated by gas binding to the heme; GGDEF domain activity is activated by the Fe(II)-NO state of the globin domain, while EAL domain activity is activated by the Fe(II)-O2 state. The in vitro activity of DcpG is mimicked in vivo by the biofilm formation of P. dendritiformis in response to gaseous environment, with nitric oxide conditions leading to the greatest amount of biofilm formation. The ability of DcpG to differentially control GGDEF and EAL domain activity in response to ligand binding is likely due to the unusual properties of the globin domain, including rapid ligand dissociation rates and high midpoint potentials. Using structural information from small-angle X-ray scattering and negative stain electron microscopy studies, we developed a structural model of DcpG, providing information about the regulatory mechanism. These studies provide information about full-length GCS protein architecture and insight into the mechanism by which a single regulatory domain can selectively control output domains with opposing enzymatic activities.


2005 ◽  
Vol 48 (5) ◽  
pp. 779-786 ◽  
Author(s):  
Nina Cláudia Barboza Silva ◽  
Andrea Furtado Macedo ◽  
Celso Luís Salgueiro Lage ◽  
Maria Apparecida Esquibel ◽  
Alice Sato

Tissue cultures of Alternanthera brasiliana (L.) Kuntze were treated with different growth regulators (Kinetin and 2,4-D), tyrosine and Ultraviolet A radiation (UV-A; 320 - 400 nm) to investigate their effects on development and pigment production. Nodal segments of plantlets grown from seeds were inoculated in all tested media and different light conditions. After eight weeks, this material was used to evaluate biomass, chlorophyll and betacyanin production. The Murashige and Skoog (MS) + kinetin medium resulted in development of approximately four shoots/explant. This medium plus white light was the best combination for micropropagation with the highest rooting percentage and betacyanin production. Plantlets grown under UV-A illumination reduced biomass accumulation and worse Chlorophyll a / Chlorophyll b ratio. Addition of 2,4-D resulted in inhibition of pigment production and growth of plantlets.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248517
Author(s):  
Takao Morimune ◽  
Ayami Tano ◽  
Yuya Tanaka ◽  
Haruka Yukiue ◽  
Takefumi Yamamoto ◽  
...  

It is not fully understood how enzymes are regulated in the tiny reaction field of a cell. Several enzymatic proteins form cytoophidia, a cellular macrostructure to titrate enzymatic activities. Here, we show that the epileptic encephalopathy-associated protein Tbc1d24 forms cytoophidia in neuronal cells both in vitro and in vivo. The Tbc1d24 cytoophidia are distinct from previously reported cytoophidia consisting of inosine monophosphate dehydrogenase (Impdh) or cytidine-5’-triphosphate synthase (Ctps). Tbc1d24 cytoophidia is induced by loss of cellular juvenescence caused by depletion of Gm14230, a juvenility-associated lncRNA (JALNC) and zeocin treatment. Cytoophidia formation is associated with impaired enzymatic activity of Tbc1d24. Thus, our findings reveal the property of Tbc1d24 to form cytoophidia to maintain neuronal cellular juvenescence.


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