scholarly journals Electrochromic Properties and Electrochemical Behavior of Marennine, a Bioactive Blue-Green Pigment Produced by the Marine Diatom Haslea ostrearia

Marine Drugs ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 231
Author(s):  
Nellie Francezon ◽  
Mickaël Herbaut ◽  
Jean-François Bardeau ◽  
Charles Cougnon ◽  
William Bélanger ◽  
...  
Keyword(s):  
Redox System ◽  
Marine Diatom ◽  
Blue Pigment ◽  
Unstable State ◽  
Green Pigment ◽  
Haslea Ostrearia ◽  
Color Changes ◽  
Yellow Color ◽  
Food Applications ◽  
Molecular Structure Investigation

Marennine has long been known as the unique peculiar pigment responsible for the natural greening of oysters. It is specifically produced by the marine diatom Haslea ostrearia and it is a natural blue molecule indeed promising for food industry because of the rarity of such non-toxic, blue-colored pigments. In the search for its still not defined molecular structure, investigation of the color changes with the redox state has been carried out combining different approaches. Reducing and oxidizing chemicals have been added to purified marennine solutions and a stable blue-green color has been confirmed for the oxidized state, while a yellow color corresponded to the reduced unstable state. Raman spectroscopy has been used to monitor changes in the Raman spectra corresponding to the different colored states, and cyclic voltammetry has allowed the detection of a redox system in which protons and electrons are exchanged. These findings show that marennine is a suitable stable blue pigment for use in food applications and help in the elucidation of the chromophore structure.

Formation of Green Pigment and Colour Changes in Orthoptera

1953 ◽  
Vol 44 (2) ◽  
pp. 299-315 ◽  
Author(s):  
Salâhattin Okay
Keyword(s):  
Fat Body ◽  
Colour Change ◽  
Blue Pigment ◽  
Breakdown Product ◽  
Bile Pigment ◽  
Green Pigment ◽  
Yellow Colour ◽  
Blue Component ◽  
Colour Changes ◽  
Background Reaction

The colour change and formation of green pigment in Mantis, Acrida, Locusta, Schistocerca and Dixippus are studied.There is no background reaction to green and brown or yellow colour in these species.Usually the young nymphs of Mantis are green; some ofthe old nymphs and adults have a tendency to lose the green pigment. Phytophagous nymphsbecome green only when fed on fresh or growing grass. Green individuals may be obtained in darkness on this food (Locusta). The green pigmentdisappears on a diet of dry grass.The colour change from non-green to green, or vice versa, is dependent on the formation or disappearance of the blue component (bile pigment-protein) of green pigment. The blue pigment generally appears first in the blood and is deposited in the integument at the following moult; it does not appear to be a breakdown product of chlorophyll or haematin. It is probably synthesised from a colourless precursor in the peripheral fat body.Observations made on the pericardial cells of Locusta suggest that the blue pigment may be converted into insectorubin.

pH Effect on Characteristics and Ammonia Sensing of Silver Nanoparticles Synthesized in the Presence of Tannic Acid

2018 ◽  
Vol 759 ◽  
pp. 98-101 ◽  
Author(s):  
Vimolvan Pimpan ◽  
Thanawan Ritthichai
Keyword(s):  
Silver Nanoparticles ◽  
Tannic Acid ◽  
Ph Effect ◽  
Acidic Condition ◽  
Spherical Particles ◽  
Ammonia Sensing ◽  
Color Changes ◽  
Yellow Color ◽  
Ph Conditions ◽  
Absorbance Peak

Silver nanoparticles were synthesized using silver nitrate as a silver precursor in the presence of tannic acid under UV radiation for 60 minutes. Various pH conditions were employed in the synthesis in order to study its effect on characteristics and ammonia sensing of the synthesized nanoparticles. The images obtained from transmission electron microscope revealed the formation of the spherical particles with average diameters in the range of 10-40 nm depending on pH conditions. It was found that using acidic condition resulted in yellow silver nanoparticles colloids with bigger particles and exhibiting a UV-visible absorbance peak at around 435 nm whereas using other conditions yielded greenish-yellow colloids with smaller particles and having two absorbance peaks at around 370 and 430 nm. After adding 100 ppm of ammonia, TEM images revealed the aggregation and the changes in size and shape of the silver nanoparticles. The color of the silver nanoparticles colloids synthesized using acidic condition changed to orange-yellow color. However, other pH conditions caused the color of the colloids became darker. These color changes were observed by the naked eyes.

scholarly journals Bacterial community structure of the marine diatom Haslea ostrearia

2016 ◽  
Vol 16 ◽  
pp. 418-426 ◽  
Author(s):  
Alexandra Lépinay ◽  
Hervé Capiaux ◽  
Vincent Turpin ◽  
Florence Mondeguer ◽  
Thierry Lebeau
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Community Structure ◽  
Marine Diatom ◽  
Haslea Ostrearia

Concentration and desalting by membrane processes of a natural pigment produced by the marine diatom Haslea ostrearia Simonsen

1999 ◽  
Vol 70 (1-3) ◽  
pp. 393-402 ◽  
Author(s):  
L. Vandanjon ◽  
P. Jaouen ◽  
N. Rossignol ◽  
F. Quéméneur ◽  
J.-M. Robert
Keyword(s):  
Marine Diatom ◽  
Natural Pigment ◽  
Membrane Processes ◽  
Haslea Ostrearia

Untersuchungen zum Redox-System Bis-(pyridin-2,6-dicarbothioato)-ferrat(II) /-ferrat(III) [1]

1984 ◽  
Vol 39 (11) ◽  
pp. 1607-1613 ◽  
Author(s):  
U. Hildebrand ◽  
J. Lex ◽  
K. Taraz ◽  
S. Winkler ◽  
W. Ockels ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Redox Reactions ◽  
Culture Medium ◽  
Redox System ◽  
Blue Pigment

Abstract The structure of the blue pigment obtained from the culture medium of Pseudomonas putida upon addition of Fe++ and the nature of its redox reactions has been elucidated.

scholarly journals Assessment of changes in color and color parameters of light-cured composite resin after alternative polymerization methods

2013 ◽  
Vol 07 (01) ◽  
pp. 110-116 ◽  
Author(s):  
Emine Sirin Karaarslan ◽  
Bulbul Mehmet ◽  
Ertas Ertan ◽  
Mehmet Ata Cebe ◽  
Aslihan Usumez
Keyword(s):  
Composite Resin ◽  
Color Change ◽  
Color Difference ◽  
Study Groups ◽  
Color Parameters ◽  
Color Changes ◽  
Yellow Color ◽  
Before And After ◽  
Total Color Change

ABSTRACTObjective:To examine the amount of change in color and color parameters of a composite resin (Filtek P60) polymerized by five different polymerization methods.Methods: A Teflon mold (6mm in diameter, 2mm in height) was used to prepare the composite resin discs (n=10). G1: Polymerization with inlay oven; G2: Polymerization with HQTH and autoclave; G3: Polymerization with LED and autoclave; G4: Polymerization with HQTH; G5: Polymerization with LED. Colorimetric values of the specimens before and after polymerization were measured using a spectrophotometer. The CIE L*a*b color system was used for the determination of color difference. Analysis of variance (ANOVA) was used to analyze the data for significant differences. Tukey’s HSD test and paired two-tailed tests were used to perform multiple comparisons (α=.05).Results: There were no significant differences in total color change (ΔE*ab) among the polymerization groups (P>.05). However, the lowest color change (ΔE*ab) value was 3.3 in LED and autoclave; the highest color change (ΔE*ab) value was 4.6 in HQTH. For all groups, CIE L*, C*ab and a*values decreased after polymerization (P<.05). The highest Δb* and ΔC*ab values were observed in specimens polymerized in an inlay oven (P<.05).Conclusion: Composite resin material showed color changes above the clinically accepted value in all study groups (ΔE*ab≥3.3). All specimens became darker during investigation (ΔL*< 0). Specimens polymerized with inlay oven presented the highest Δb* values which means less yellow color in specimens. (Eur J Dent 2013;7:110-116)

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