⊿2,10-Phytadienol as Esterifying Alcohol of Bacteriochlorophyll b from Ectothiorhodospira halochloris

1981 ◽  
Vol 36 (5-6) ◽  
pp. 417-420 ◽  
Author(s):  
R. Steiner ◽  
W. Schäfer ◽  
I. Bios ◽  
H. Wieschhoff ◽  
H. Scheer
Keyword(s):  
Mass Spectroscopy ◽  
Hplc Analysis ◽  
Photosynthetic Bacterium ◽  
Vis Spectroscopy ◽  
Ectothiorhodospira Halochloris ◽  
Bacteriochlorophyll B ◽  
The One

Abstract Bacteriochlorophyll b (bchl b) has been isolated from the halophilic photosynthetic bacterium, Ectothiorhodospira halochloris. The pigment and a series of derivatives thereof are different from Bchl b from Rhodopseudomonas viriais by HPLC analysis, but similar by uv-vis spectroscopy. The chromatographic difference originates in different esterifying alcohols in the two pigments. The one from Rp. viridis (Bchl bp) is esterified with ⊿2-phytaenol (phytol), that from E. halochloris (Bchl b⊿2,10) with ⊿2,10-phytadienol. The structure of the latter has been established by isolation of the alcohol from the purified pigment, followed by (i) gaschromatography-mass spectroscopy and (ii) ozonolysis and dinitrophenylhydrazon-formation of the cleavage products, which were identified by gaschromatography-mass spectroscopy as 6-methyl-heptan-2-one, and 4-methyl-nona-1,8-dione.

scholarly journals Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Emilia Tomaszewska ◽  
Katarzyna Soliwoda ◽  
Kinga Kadziola ◽  
Beata Tkacz-Szczesna ◽  
Grzegorz Celichowski ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Point Of View ◽  
Spectroscopy Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The One

Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

scholarly journals Zinc(II) and copper(II) complexes with pheophytin and mesoporphyrin and their stability to UV-B irradiation: Vis spectroscopy studies

2012 ◽  
Vol 77 (2) ◽  
pp. 187-199 ◽  
Author(s):  
Jelena Zvezdanovic ◽  
Dejan Markovic ◽  
Sanja Milenkovic
Keyword(s):  
Heavy Metal ◽  
The Other ◽  
First Order ◽  
Absorbance Spectroscopy ◽  
First Order Kinetics ◽  
Porphyrin Derivatives ◽  
Vis Spectroscopy ◽  
Photochemical Decomposition ◽  
Spectroscopy Studies ◽  
The One

Stability of Zn(II) and Cu(II) complexes of porphyrin derivatives (pheophytin and mesoporphyrin) to UV-B -irradiation has been studied by absorbance spectroscopy in 95% ethanol. The chosen porphyrins as well as their heavy metal complexes undergo photochemical decomposition obeying first-order kinetics. In general, pheophytin is more stable than mesoporphyrin to UV-B irradiation. On the other hand, stability of Zn(II)-complex is smaller than Cu(II)-complex both for pheophytin and mesoporphyrin; however while Cu(II)-complex with pheophytin is more stable than the one with mesoporphyrin, with Zn(II)-complex the situation is vice versa.

scholarly journals Electrochemical Biosensor Based on Furosemide-Gold Nanoparticles for The Determination of Dopamine for Practical Applications

2021 ◽  
Vol 5 (1) ◽  
Keyword(s):  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Limit Of Quantification ◽  
Strong Absorption Band ◽  
Amperometric Determination ◽  
Practical Applications ◽  
Vis Spectroscopy ◽  
The One

In this study, by taking the advantage of the facile & controlled synthesis of furosemide derived gold nanoparticles (Fr-AuNps) for rapid and sensitive amperometric determination of dopamine (DP). The one-step synthesis of FrAuNps was carried out at room temperature without the use of strong reducing agents. The synthesized Fr-AuNps were studied by UV-Vis spectroscopy, and a strong absorption band for gold nanoparticles was observed at 520 nm. Transmission electron micrographs (TEM) revealed the average particle size below 100 nm. HRTEM showed excellent crystalline features as prepared gold nanoparticles. The electrochemical behavior of gold nanoparticles was examined by cyclic voltammetry (CV) which demonstrated the enhanced electrocatalytic kinetics activity towards the oxidation of dopamine. The presented dopamine biosensor exhibited a linear response for the dopamine in the range of 0.25 to 7 µM. The calculated the detection limit found to be 18.3 nM and limit of quantification 61.5 nM respectively. The proposed dopamine biosensor was successfully employed for the quantification of trace amount of dopamine from human serum and the obtained results are very satisfactory.

scholarly journals Screening and partial purification of photoprotective pigment scytonemin from cyanobacterial crusts dwelling on the historical monuments in and around Varanasi, India

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Jainendra Pathak ◽  
Arun S. Sonker ◽  
R. Richa ◽  
R. Rajneesh ◽  
Vinod K. Kannaujiya ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Solar Radiation ◽  
Spectroscopic Data ◽  
High Performance ◽  
Hplc Analysis ◽  
Partial Purification ◽  
Cyanobacterial Species ◽  
Historical Monuments ◽  
Vis Spectroscopy ◽  
Almost All

In the present investigation, biological crusts from the surface of eight historical monuments of Varanasi, India, were examined for the presence of scytonemin (a cyanobacterial photoprotective pigment) containing cyanobacterial species. Lyngbya sp. and Scytonema sp. were the dominant cyanobacteria present in all crust samples. The absorption spectroscopic data of chlorophyll, carotenoids and scytonemin showed that scytonemin was more abundant than the carotene and chlorophyll in all the crusts. Identification of these compounds was done using UV-Vis spectroscopy and High Performance Liquid Chromatography (HPLC) analysis. HPLC analysis revealed the presence of scytonemin in seven out of eight samples and peaks of scytonemin with retention time ranging from 1.4-1.9 min with corresponding absorbance maxima at 386, 300 and 252±2 nm. As per our knowledge this is the first report of its kind from monuments of Varanasi. From this study, it can be concluded that synthesis of photoprotective compounds like scytonemin and its derivatives counteract the damaging effects of solar radiation which enable cyanobacteria to colonize and inhabit almost all kinds of habitats, including extreme lithic habitats, such as rocks and walls of monuments which face prolonged high intensity solar radiation.

scholarly journals Synthesis and Anticancer Activity of Mixed Ligand, Cobalt (II), Nickel (II), Manganese (II) Complexes of Tertiary Diphosphines with Dithizone (H2dz)

2018 ◽  
Vol 34 (4) ◽  
pp. 1919-1925 ◽  
Author(s):  
Hikmat Ali Mohamad
Keyword(s):  
Cancer Cell Line ◽  
Molar Conductance ◽  
Human Breast Cancer Cell ◽  
Mixed Ligand ◽  
Human Breast ◽  
Anticancer Activities ◽  
One Pot ◽  
Vis Spectroscopy ◽  
Colored Complexes ◽  
The One

The one-pot synthesis reaction of one mole MCl2.nH2O, where M= Co(II), Ni(II), Mn(II) ,with one mole of 1,5-diphenylthiocarbazone (dithizone;H2dz), of 1,1-bis(diphenyl phosphine)ferrocene (dppf) and 1,2-bis(diphenyl phosphine) ethane (dppe) gave colored complexes of; [Co(Hdz)(k2-dppf)]Cl, [Ni(Hdz)(k2-dppf)]Cl, [Ni(Hdz)(k2-dppe)]Cl and [Mn(Hdz)(k2-dppf)]Cl. The synthesized complexes have been identified by using 1HNMR, IR, UV-Vis spectroscopy, micro elemental analysis and molar conductance. All complexes were tested for their anticancer activities on Human breast cancer cell line CAL5. The results showed that [Ni(Hdz)(k2-dppe)]Cl and[Mn(Hdz)(k2-dppf)]Cl have a highest activities than cisplatin in compared to; [Co(Hdz)(k2-dppf)]Cl, [Ni(Hdz)(k2-dppf)]Cl.

scholarly journals Multivariate Model Based on UV-Vis Spectroscopy and Regression in Partial Least Squares for Determination of Diameter and Polydispersity of Silver Nanoparticles in Colloidal Suspensions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
J. F. B. Rodrigues ◽  
E. P. S. Junior ◽  
K. S. Oliveira ◽  
M. R. R. Wellen ◽  
S. S. Simões ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Multivariate Calibration ◽  
Volume Ratio ◽  
Colloidal Suspensions ◽  
Prediction Errors ◽  
Predictive Capacity ◽  
Vis Spectroscopy ◽  
Characterization Of Properties ◽  
The One

In the universe of nanomaterials, silver nanoparticles (AgNPs) have attracted the attention of researchers because of their optical, catalytic, antimicrobial, fungicidal, and bactericidal properties. Recently, studies have correlated the toxicity and efficacy of antimicrobial activity with surface-volume ratio, morphology, polydispersity, ligand types, particle size, and stability of AgNPs. Soon, the need for characterization of properties such as diameter and polydispersity is clear. The methodologies conventionally used for characterization of AgNPs, although accurate, are generally expensive and laborious and can degrade the sample. Thus, the development of methodologies based on UV-Vis spectroscopy and chemometric techniques appears as an alternative for the characterization of diameter and polydispersity of the nanoparticles. For the development of the methodology in question, 50 samples were synthesized, varying the type, volume, and concentration of the reagents in order to increase the diameter and polydispersity values. All samples were analyzed by DLS and UV-Vis spectroscopy. For the construction of multivariate calibration models, the calibration and validation sets were selected using the SPXY algorithm, and their predictive capacity was evaluated based on the method figures. The model that presented the best predictive capacity was the one built with the pretreated spectra with the 1st derivative with a 15-point window and 2nd-order polynomial, providing prediction errors of 5.31% and 4.43% for diameter and polydispersity, respectively.

The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity

1986 ◽  
Vol 41 (9-10) ◽  
pp. 873-880 ◽  
Author(s):  
R. Steiner ◽  
B. Kalumenos ◽  
H. Scheer
Keyword(s):  
Molecular Weight ◽  
Reaction Center ◽  
Photosynthetic Apparatus ◽  
Photochemical Activity ◽  
Proteinase K ◽  
Proteolytic Digestion ◽  
Polypeptide Composition ◽  
Difference Spectra ◽  
Ectothiorhodospira Halochloris ◽  
The One

Abstract Photsynthetic membranes of Rhodopseudomonas virids and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn’t show the typical absorption shift of the antenna (B 800/1020 → B 800/960). The results are discussed quantitatively and compared to those obtained from Bchl α containing organisms.

scholarly journals A Facile Green Fabrication and Characterization of Cellulose-Silver Nanoparticle Composite Sheets for an Antimicrobial Food Packaging

2021 ◽  
Vol 8 ◽  
Author(s):  
Seongyoung Kwon ◽  
Wooseok Lee ◽  
Jung Wook Choi ◽  
Nattinee Bumbudsanpharoke ◽  
Seonghyuk Ko
Keyword(s):  
Photoelectron Spectroscopy ◽  
Food Packaging ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Hydroxyl Groups ◽  
Green Approach ◽  
Vis Spectroscopy ◽  
One Step ◽  
The One

The present study focused on a facile and green approach for the one-step synthesis of silver nanoparticles (AgNPs) embedded in hard wood bleached kraft fiber. The hydroxyl groups on the cellulose chain induced ionic silver reduction with additional hydrothermal energy, allowing for the in situ formation and deposition of AgNPs on the cellulose fiber. The white color of the bleached fiber transformed to yellow due to the formation of AgNPs. UV-Vis spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy revealed that the AgNPs were uniformly distributed across the surface of the obtained cellulose fibers. The results indicated that the formation and distribution of AgNPs on surface of cellulose fibers was significantly influenced by the amount and concentration of silver nitrate (AgNO3). The antimicrobial activity of the cellulose-AgNP composite sheet against Escherichia coli was found to be inhibiting. These findings imply that cellulose-AgNP composite sheets can be feasibly used as antimicrobial paper for food packaging.

scholarly journals Method validation in pharmaceutical analysis: from theory to practical optimization

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Jaqueline Kaleian Eserian ◽  
Márcia Lombardo
Keyword(s):  
High Performance Liquid Chromatography ◽  
Method Validation ◽  
Pharmaceutical Analysis ◽  
High Performance ◽  
Hplc Analysis ◽  
Quality Data ◽  
High Quality ◽  
High Quality Data ◽  
Validation Procedure ◽  
The One

The validation of analytical methods is required to obtain high-quality data. For the pharmaceutical industry, method validation is crucial to ensure the product quality as regards both therapeutic efficacy and patient safety. The most critical step in validating a method is to establish a protocol containing well-defined procedures and criteria. A well planned and organized protocol, such as the one proposed in this paper, results in a rapid and concise method validation procedure for quantitative high performance liquid chromatography (HPLC) analysis.   Type: Commentary

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