DOCSLIB.ORG

Solar Cells Based on Dyes Asok K

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Solar Cells Based on Dyes Asok K Journal of Photochemistry and Photobiology A: Chemistry 132 (2000) 1–17 Review Solar cells based on dyes Asok K. Jana Department of Chemistry, Mahatma Gandhi Government Arts College, Mahe, Pondicherry 673311, India Received 24 September 1999; accepted 4 December 1999 Abstract From early developments to recently developed stages of solar cells have been discussed in details, considering the effect of different parameters. In this paper, primitive photoelectrochemical (PEC) cell and PEC cell with Fe–thionine and different dyes-reducing agent have been reviewed. Solar cell with phenazine dyes have also been pointed out separately since these dyes give more output in solar cell. The use of inorganic semiconductor electrode (e.g. SnO2,In2O3 and ZnO) and utilization of semiconducting properties of organic dyes in PEC cell have been mentioned. Furthermore, utilization of surfactant media for storage of solar energy and production of hydrogen from solar cell using dye are also included. ©2000 Elsevier Science S.A. All rights reserved. Keywords: Dyes; Photochemical cells; Photopotential; Photocurrent 1. Introduction A list of abbreviations and symbols is mentioned at the end of this paper as a large numbers of chemical systems The search for renewable sources of energy has led to have been cited here. an increasing interest in photochemical cells because of their possible role as transducers of solar to electrical en- 1.1. A primitive PEC cell ergy. The photoeffects in electrochemical systems were first observed by Becquerel [1] in his investigation on the Anciently a photochemical cell is composed with inert solar illumination on metal electrodes in 1839. Later it was metal electrodes immersed in two redox couple [i.e. A/B observed by Moser [2] and Rigollot [3] that the sensitivity (light sensitive) and Y/Z] and the best performance is ob- of silver/silver halide and copper/copper oxide electrode tained if one couple (e.g. A/B) is highly reversible and the could be increased by coating them with a dye stuff. Thomp- other (Y/Z) is highly irreversible [9]. As a result, the reac- son [4] and Stora [5] reported that pure metal electrodes tion occurs in the light and dark are as follows: were also sensitive to light when coated with a dye or im- Light mersed in a dye solution. The result of the first 100 years A + Z B + Y (1) had been reviewed by Copeland and co-workers [6]. A Dark summary of the properties of photoelectrochemical (PEC) Furthermore, optimum output of power depends on the cells described in the literature upto 1965 was compiled by cell length, the concentration of A, Y and Z, the kinetics of Kuwana [7] and later work has been reviewed by Archer the homogeneous reaction B+Y, the extinction coefficient [8]. of A, and the cell load [10,11]. This review paper is comprised of evolution of solar cell In this comprehensive mode cell, five major types from the very beginning stage and it includes vast field of re- of process [12] occurs which are (i) the intermolecular search in PEC cell in which dyes are used for photoeffected oxidation–reduction reactions in the dark of the solution and electron-transfer reaction. The basic principles of PEC cell at the electrode, (ii) the electrodic charge transfer reactions, are not discussed here. PEC cell are of three types i.e. pho- (iii) the steps for the conversion of bulk species to surface togalvanic (PG), photovoltaic (PV) and photogalvanovoltaic species with or without the possibility of adsorption, (iv) (PGV). So, these three types of PEC cell are considered in direct photochemical pathways, and (v) the photochemical different sections of this paper. side reactions. 1010-6030/00/$ – see front matter ©2000 Elsevier Science S.A. All rights reserved. PII: S1010-6030(99)00251-8 2 A.K. Jana / Journal of Photochemistry and Photobiology A: Chemistry 132 (2000) 1–17 1.2. PEC cell with dyes 1.2.1. Iron–thionine system A particularly striking example of an oxidation–reduction Generally inorganic elements possess redox properties be- system, in which light is converted to a marked proportion cause of large electronegativity difference between bonded into chemical energy, is the iron–thionine system observed elements. The organo-metallic and heterocompounds (e.g. by Weber [13] firstly. The reaction was reversible in the dark, dye) like inorganic element also show redox property al- but could be driven in an irreversible manner by precipitation though they are covalent in nature. So dye molecules, hav- of the simultaneously formed ferric ions (Weiss) [14]. The ing redox property as well as light sensitivity, can be used in PEC effect of this Fe(II)–thionine system was first seriously comprehensive solar cell as a redox couple among the two considered by Rabinowitch [15]. which is mentioned in model primitive cell. The structure The cell characteristics of Fe(II)–thionine PG cell are and absorption wavelength maxima of some dyes are listed reported by many authors, few of them are mentioned in in Table 1. They are commonly used in this paper. Table 2. Table 1 The structure and absorption maxima of five classes of dyes Dye Class Structure λmax (nm) Thionine (TH+) Thiazines 596 Toluidine blue (Tb+) Thiazines 630 Methylene blue (MB) Thiazines 665 New methylene blue Thiazines 650 Azure A Thiazines 635 Azure B Thiazines 647 Azure C Thiazines 620 Phenosafranin (PSF) Phenazines 520 Safranin-O (Saf-O/SO) Phenazines 520 Safranin-T (Saf-T/ST) Phenazines 520 Neutral red (NR) Phenazines 534 Fluorescein Xanthenes 490 A.K. Jana / Journal of Photochemistry and Photobiology A: Chemistry 132 (2000) 1–17 3 Table 1. (Continued) Dye Class Structure λmax (nm) Erythrosin Xanthenes 530 Erythrosin B Xanthenes 525 Rhodamine B (Rh. B) Xanthenes 551 Rose bengal Xanthenes 550 Pyronine Y (PY) Xanthenes 545 Eosin Xanthenes 514 Rhodamine 6G Xanthenes 524 Acridine orange (AO) Acridines 492 Proflavin (PF) Acridines 444 Acridine yellow (AY) Acridines 442 Fuchsin Triphenyl methane derivatives 545 Crystal violet Triphenyl methane derivatives 578 Malachite green Triphenyl methane derivatives 423, 625 Methyl violet Triphenyl methane derivatives 580 4 A.K. Jana / Journal of Photochemistry and Photobiology A: Chemistry 132 (2000) 1–17 Table 2 Cell characteristics of PG cell with Fe(II)–thionine system Photovoltage (mV) Short-circuit current (ISC)(␮A) Solar energy efficiency (SEE) % Reference 10–240 – – [15] 185 – 3×10−4 [16] – – 30-fold of [16] [17] 230 (pH 4.0) – – [18] – – 2.36×10−1 [19] 138 26.3 – [20] 900 80.0 – [21] – – 1.1×10−2 [22] The thionine–Fe(II) aqueous PG system was studied ex- P/D=33. Yamad et al. [40] also observed greater photo- tensively [23–30] but the basic mechanism of the PG effect potential with thionine-poly(imino-ethylene) compared was unknown initially. However, Hatchard et al. [31] and to thionine-monoamine. Even thionine coated electrode Albery et al. [32] established the sequence of reactions in [41–44] favours irreversible oxidation process over reduc- Fe–thionine cell which are as follows: tion process but Harrison et al. [45] reported 19 times reduced power conversion efficiency with thionine coated + hν 1 + 3 + TH → TH → TH gold electrode compared to uncoated electrode. Kamat [46] − + + + also reported very low efficiency i.e. 10 4% with thionine 3TH + H → 3TH 2 2 dye incorporated Pt clay modified electrode. 3 2+ + + TH2 → TH + H (ISC to ground state) Lichtin et al. [47] developed the totally illuminated thin layer (TITL) iron–thionine PG cell and studied the elec- trodic phenomena at the anode of this cell. Albery [48] also 3 2+ + 2+ → • + + 3+ TH2 Fe TH2 Fe discussed theoretical principles regarding kinetics, electrode (Semi-thionine radical formation) selectivity and efficiency of the TITL cell. Natarajan et al. [49,50] approached the electrode coated method to TITL • + + + + + system using polymer bounded thionine coated on SnO TH + Fe3 → TH + Fe2 + H 2 2 electrode and clean Pt electrode, and obtained maximum ( ) Back thermal reaction power output compared to earlier study [39]. They proposed the following mechanism • + • + + + at the cathode: TH2 + TH2 TH + TH3 (Disproportionation reaction) + 2+ + hν 4+ P − TH + Fe + H → [P–TH2–Fe] 4+ + − → − • + + 2+ • + + + − [P–TH2–Fe] e P TH2 Fe TH2 → TH + H + e (Anode reaction at illuminated electrode) at the anode: + − + + − + Fe3 + e → Fe2 (Dark electrode). Fe2 − e → Fe3 . Thionine was represented by TH+, since in the dark Mechanism shows that the oxidation of the thionine in the + 4+ thionine is in the oxidized form TH . complex [P–TH2–Fe] present near the electrode, occurs Still, the photoenergy conversion is very low mainly due slowly for which efficiency of cell increases. The photocur- to back thermal reaction between reduced dye and Fe(III) rent of TITL system [51] with bare and thionine coated Pt [33,34] and formation of local cells. Last factor can be re- electrode increases to some extent by the addition of F− ion. duced if the Fe(II)–thionine system is studied in heteroge- The Kinetics of iron–thionine system have been studied neous cell. Kamat et al. [35–38] reported the better power by the steady state illumination [23,24,26,52–54] and flash output of heterogeneous cell than homogeneous cell which photolysis techniques [55,56]. Employing a cross beam il- are 0.022 and 0.001%, respectively. lumination kinetic spectrophotometry technique, Kamat et In order to decrease the back reaction of this sys- al. [57] studied the oxidation of leuco-thionine by Fe(III) in tem, Natarajan et al. [39] constructed a PG cell with aqueous solution i.e. the kinetics of photobleaching recov- Fe(II) and thionine coated with poly(N-methyl acry- ery. The photobleaching recovery follows pseudo first-order 2+ lamide), and observed that open-circuit voltage (VOC) kinetics through complex formation between TH4 and and ISC of this system increased with increase in ra- Fe(III), and the rate constant increases with increase in pH, tio of P/D (polymer/dye) and reached maxima with light intensity and temperature.
Load more

Recommended publications
  • Gst Gram Staining Learning Objectives the Student Will  Use Aseptic Techniques in the Safe Inoculation of Various Forms of Media
    GSt Gram Staining Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. Follow oral and written instructions and manage time in the lab efficiently. Use the bright field light microscope to view microbes under oil immersion, make accurate observations and appropriate interpretations and store the microscope according to lab procedures. Properly prepare a bacterial smear for accurate staining and describe the chemical basis for simple staining and negative staining. Background/Theory Differential staining distinguishes organisms based on their interactions with multiple stains. In other words, two organisms may appear to be different colors. Differential staining techniques commonly used in clinical settings include Gram staining, acid-fast staining, endospore staining, flagella staining, and capsule staining. This link to the OpenStax Microbiology text provides more detail on these differential staining techniques. (OpenStax CNX, 2018) The Gram stain is a differential staining procedure that involves multiple steps. It was developed by Danish microbiologist Hans Christian Gram in 1884 as an effective method to distinguish between bacteria containing the two most common types of cell walls. (OpenStax CNX, 2018) One type consists of an inner plasma membrane and a thick outer layer of peptidoglycan. The other type consists of a double phospholipid Figure 1 Simplified structures of Gram negative cells (left) and Gram positive bilayer with a thin layer of cells (right) peptidoglycan between the two. The Gram Staining technique remains one of the most frequently used staining techniques. The steps of the Gram stain procedure are listed below and illustrated in Figure. (OpenStax CNX, 2018) 1.
    [Show full text]
  • The Suitability of Certain Stains 3R Studying Lignification in Balsam Fir, Ibies Balsamea (L.) Mill
    The suitability of certain stains 3r studying lignification in balsam fir, ibies balsamea (L.) Mill Kutscha and Gray Technical bulletin 53 March 1972 Life Sciences and Agriculture Experiment Station Cover photo: Safranin and aniline blue, showing blue unlignified cambium (top of photo) and contrasting red lignified tissue (lower part of photo). Imma­ ture, secondary walls appear blue-blue green and can be seen approximately five to eight cells down from the cambial region. Section of FAA-killed and celloidm embedded compression wood sample collected July 6, 1966; X 320. ABSTRACT An investigation was conducted to examine the suitability of ten staining reactions for studying lignification in balsam fir, Abies balsamea (L.) Mill. Two experiments were carried out on material collected on two different dates. In each experiment slides of fresh, FAA-killed and FAA-killed celloldin-embedded material of normal and compression wood were stained and evaluated. No significant difference in staining reactions was found between material collected on different dates. In each experiment, the embedded material showed somewhat superior results compared with the fresh and FAA-killed material with at least half of the stains. No marked difference was observed between normal and compression wood. This study emphasized the need for considsring each of the ten staining reactions on an individual basis, since each has particular ad­ vantages and disadvantages as emphasized throughout the study. Stain­ ing schedules were prepared and tables compiled to determine
    [Show full text]
  • Revisions Inserts Rev from Rev to JOB
    BALTSO0191 Version 11.0 Template 4 Revisions Inserts Rev from Rev to JOB # 06 07 52-17 Notes: 1. BD Catalog Number: 212525, 212526, 212527, 212528, 212531, 212532, 212539, 212542, 212543, 212544, 212545 2. Blank (Sheet) Size: Length: 25.5” Width: 22” 3. Number of Pages: 28 Number of Sheets: 1 4. Page Size: Length: 8.5” Width: 5.5” Final Folded Size: 4.25” x 5.5” 5. Ink Colors: No. of Colors: 2 PMS#: 032 Red; Standard Black 6. Printed two sides: Yes X No 7. Style (see illustrations below): # 5 W W W W W W W 8. Vendor Printed X Online/In House Printed Web 9. See specication control no. N/A for material information. 10. Graphics are approved by Becton, Dickinson and Company. Supplier has the responsibility for using the most current approved revision level. Label Design COMPANY CONFIDENTIAL. THIS DOCUMENT IS THE PROPERTY OF BECTON, DICKINSON AND Becton, Dickinson and Company Proofer COMPANY AND IS NOT TO BE USED OUTSIDE THE COMPANY WITHOUT WRITTEN PERMISSION. 7 Loveton Circle Sparks, MD 21152 USA Checked By Category and Description Sheet: 1 of 29 Part Number: Package Insert, 8820191JAA Gram Stain Kits and Reagents Scale: N/A A B Gram Stain Kits and Reagents English: pages 1 – 5 Italiano: pagine 14 – 18 8820191JAA(07) Français : pages 5 – 9 Español: páginas 19 – 23 2017-09 Deutsch: Seiten 10 – 14 Contact your local BD representative for instructions. / Свържете се с местния представител на BD за инструкзии. / Pokyny vám poskytne místní zástupce společnosti BD. / Kontakt den lokale BD repræsentant for at få instruktioner.
    [Show full text]
  • Bidirectional Redox Cycling of Phenazine-1-Carboxylic Acid by Citrobacter Portucalensis MBL
    bioRxiv preprint doi: https://doi.org/10.1101/2020.11.23.395335; this version posted November 24, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Bidirectional redox cycling of phenazine-1-carboxylic acid by Citrobacter portucalensis MBL 2 drives increased nitrate reduction 3 4 Lev M. Tsypina and Dianne K. Newmana,b# 5 6 a Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, 7 CA, USA 8 bDivision of Geological and Planetary Sciences, California Institute of Technology, Pasadena, 9 CA, USA 10 11 Running Head: C. portucalensis MBL links PCA and nitrate redox cycles 12 13 # Address correspondence to Dianne K. Newman, [email protected] 14 bioRxiv preprint doi: https://doi.org/10.1101/2020.11.23.395335; this version posted November 24, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 15 ABSTRACT 16 Phenazines are secreted metabolites that microbes use in diverse ways, from quorum sensing to 17 antimicrobial warfare to energy conservation. Phenazines are able to contribute to these activities 18 due to their redox activity. The physiological consequences of cellular phenazine reduction have 19 been extensively studied, but the counterpart phenazine oxidation has been largely overlooked.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 6,242,602 B1 Giri Et Al
    USOO62426O2B1 (12) United States Patent (10) Patent No.: US 6,242,602 B1 Giri et al. (45) Date of Patent: Jun. 5, 2001 (54) ONE POTSYNTHESIS OF G. F. Bettinetti et al., “Synthesis of 5, 10-Dialkyl-5, 5,10-DIHYDROPHENAZINE COMPOUNDS 10-dihydrophenazines”, Synthesis, Nov. 1976, pp. 748-749. AND 5,10-SUBSTITUTED DHYDROPHENAZINES B. M. Mikhailov et al., “Metal Compounds of Phenazine and Their Transformations', 1950, Chemical Abstracts, vol. 44, (75) Inventors: Punam Giri; Harlan J. Byker; Kelvin pp. 9452–9453. L. Baumann, all of Holland, MI (US) Axel Kistenmacher et al., “Synthesis of New Soluble Triph (73) Assignee: Gentex Corporation, Zeeland, MI (US) enodithiazines and Investigation of Their Donor Properties”, Chem. Ber, 1992, 125, pp. 1495–1500. (*) Notice: Subject to any disclaimer, the term of this Akira Sugimoto et al., “Preparation and Properties of Elec patent is extended or adjusted under 35 tron Donor Acceptor Complexes of the Compounds Having U.S.C. 154(b) by 0 days. Capto-Dative Substituents', Mar.-Apr. 1989, vol. 26, pp. (21) Appl. No.: 09/280,396 435-438. (22) Filed: Mar. 29, 1999 Primary Examiner Richard L. Raymond (51) Int. Cl." ....................... C07D 241/46; CO7D 241/48 ASSistant Examiner Ben Schroeder (52) U.S. Cl. ............................................. 544/347; 544/347 (74) Attorney, Agent, or Firm-Brian J. Rees; Factor & (58) Field of Search ............................................... 544/347 Partners, LLC (56) References Cited (57) ABSTRACT U.S. PATENT DOCUMENTS Dihydrophenazines and bis(dihydrophenazines) are pre 2,292,808 8/1942 Waterman et al. .................. 260/267 pared in high yield under commercially viable reaction 2,332,179 10/1943 Soule ..................................
    [Show full text]
  • GRAM STAIN REAGENTS - for in Vitro Use Only - Catalogue No
    GRAM STAIN REAGENTS - For in vitro use only - Catalogue No. SG51-55 Our Gram-Stain Reagents are intended to be The last step is the application of a counterstain. The used as a differential stain for the microscopic most common counterstain is safranin, which colors examination of bacterial cultures and laboratory decolorized cells pink. An alternate counterstain is basic specimens. fuchsin, which gives the decolorized cells more of a Gram staining is the single most useful test in bright pink or fuchsia coloration. The basic fuchsin the microbiology laboratory given its simplicity and counterstain works particularly well for anaerobic ability to differentiate bacteria into two main bacteria, but poorly for Legionella and Bordetella groups: gram-positive organisms and gram negative species. organisms. Hans Christian Joachim Gram first devised the original procedure in the late 19 th century, and although modifications have since been Formulation per Litre made, the basic principles and results remain the same. Our formulation is often referred to as the SG51 Gram Crystal Violet Hucker Modification. The staining spectrum includes almost all Crystal Violet ................................................ 20.0 g bacteria, many fungi, and parasites such as Ammonium Oxalate ....................................... 8.0 g Trichomonas , Strongyloides , and protozoan cysts. Methanol ................................................. 200.0 mL The notable exceptions include intracellular pathogens such as Chlamydia and Rickettsia , and SG52 Gram Iodine those organisms lacking a true cell wall such as Mycobacterium , Mycoplasma , and Ureaplasma . Iodine Crystals .............................................. 3.33 g The differential properties of the staining Potassium Iodide ........................................... 6.67 g process are attributed to the differences in composition between gram-positive and gram- SG53 Gram Decolorizer negative cell walls.
    [Show full text]
  • How to Construct and Use a Simple Device to Prevent the Formation of Precipitates When Using Sudan Black B for Histology
    Acta Botanica Brasilica 29(4): 489-498. 2015. doi: 10.1590/0102-33062015abb0093 How to construct and use a simple device to prevent the formation of precipitates when using Sudan Black B for histology João Marcelo Santos de Oliveira1 Received: April 17, 2015. Accepted: July 1, 2015 ABSTRACT The present work aims to demonstrate the stages of fabrication and use of a simple device to avoid the formation or fixa- tion of precipitates from Sudan Black B solution on tissues. The device consists of four coverslip fragments attached to a histology slide, which serve as points of support for the histological slide under analysis. To work properly, the histology slide with the sections should be placed with the sections facing downwards the device. A small space between the device and the histology slide is thereby created by the height of the coverslip fragments. When Sudan Black B is applied, the solution is maintained within the edges of the device and evaporation is minimized by the small space, thereby reducing the consequent formation of precipitates. Furthermore, by placing the sections facing downward the device, any sporadically formed precipitates are prevented from settling on and fixing to the sectioned tissues or organs. By avoiding the formation of precipitates, plant cells, tissues and organs can be better observed, diagnosed and photomicrographically recorded. Keywords: histochemical tests, histology, lipids, plant anatomy, Sudan Black B Introduction for organic solvents, printer ink, varnishes, resins, oils, fats, waxes, cosmetics and contact lenses. Sudan reagents, including the traditional Sudan III, IV Lansink (1968) isolated two pure fractions of Sudan and Sudan Black B (SBB), are widely utilized to determine Black B, in addition to impurities, and denominated them lipids (Horobin 2002) in animals, plants and hydrophobic SBB-I and SBB-II.
    [Show full text]
  • Alumina Sulfuric Acid (ASA)
    Reviews and Accounts ARKIVOC 2015 (i) 70-96 Alumina sulfuric acid (ASA), tungstate sulfuric acid (TSA), molybdate sulfuric acid (MSA) and xanthan sulfuric acid (XSA) as solid and heterogeneous catalysts in green organic synthesis: a review Rajesh H. Vekariya and Hitesh D. Patel * Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India E-mail: [email protected] DOI: http://dx.doi.org/10.3998/ark.5550190.p008.894 Abstract In this comprehensive review, we report on the sulfonic acid functionalized solid acids such as alumina sulfuric acid (ASA), tungstate sulfuric acid (TSA), molybdate sulfuric acid (MSA) and xanthan sulfuric acid (XSA) as green and heterogeneous catalysts in a wide range of organic transformations. Recently, the use of sulfonic acid functionalized solid acids as catalyst in organic synthesis has become an efficient and green strategy for the selective construction of organic motifs. The sustainable advantage of sulfonic acid functionalized solid acids is that it can be recovered and reused several times without loss of their efficiency. In this review, we attempt to give an overview of the use of ASA, TSA, MSA, XSA as catalysts in the synthesis of various organic compounds having industrial as well as pharmaceutical applications. Keywords: Alumina sulfuric acid, tungstate sulfuric acid, molybdate sulfuric acid, xanthan sulfuric acid, heterogeneous catalysts, solid acid catalyst Table of Contents 1. Introduction 2. Alumina Sulfuric Acid (ASA) 2.1. Synthesis of benzimidazoles and quinoxalines 2.2. Nitration of aromatic compounds 2.3. Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles 2.4. Chemoselective dithioacetalization and oxathioacetalization 2.5.
    [Show full text]
  • Fluorescens 2-79 (NRRL B-15132) PETER G
    ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Dec. 1987, p. 1967-1971 Vol. 31, No. 12 0066-4804/87/121967-05$02.00/0 Copyright © 1987, American Society for Microbiology Revised Structure for the Phenazine Antibiotic from Pseudomonas fluorescens 2-79 (NRRL B-15132) PETER G. BRISBANE,'* LESLIE J. JANIK,1 MAX E. TATE,2 AND RICHARD F. 0. WARREN2 Division of Soils, Commonwealth Scientific and Industrial Research Organisation,' and Department ofAgricultural Biochemistry, Waite Agricultural Research Institute,2 Glen Osmond, South Australia 5064, Australia Received 24 February 1987/Accepted 21 September 1987 A phenazine antibiotic (mp, 243 to 244°C), isolated in a yield of 134 ,ug/ml from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132), was indistinguishable in all of its measured physicochemical (melting point, UV and infrared spectra, and gas chromatography-mass spectrometry data) and biological properties from synthetic phenazine-1-carboxylic acid. Gurusiddaiah et al. (S. Gurusiddaiah, D. M. Weller, A. Sarkar, and R. J. Cook, Antimicrob. Agents Chemother. 29:488-495, 1986) attributed a dimeric phenazine structure to an antibiotic with demonstrably similar properties obtained from the same bacterial strain. Direct comparison of the physicochemical properties of the authentic antibiotic obtained from D. M. Weller with synthetic phenazine-1-carboxylic acid and with the natural product from the present study established that all three samples were indistinguishable within the experimental error of each method. No evidence to support the existence of a biologically active dimeric species was obtained. Phenazine-1-carboxylic acid has a pKa of 4.24 ± 0.01 (25°C; I = 0.09), and its carboxylate anion shows no detectable antimicrobial activity compared with the active uncharged carboxylic acid species.
    [Show full text]
  • DIFFERENTIAL STAINING, Part I
    DIFFERENTIAL STAINING, Part I Differential staining is a procedure that takes advantage of differences in the physical and chemical properties of different groups of bacteria. It allows us to differentiate between different kinds of bacterial cells or different parts of a bacterial cell. I. GRAM STAIN The most commonly used differential stain is the Gram stain, first described in 1884 by Christian Gram, a Danish physician. The Gram reaction divides bacteria into two groups, those which are Gram-positive and those which are Gram-negative. Those organisms which retain the primary stain (crystal violet) are stained purple and are designated Gram-positive; those which lose the crystal violet and are subsequently stained by a safranin counterstain appear red and are designated Gram-negative. The conventional Gram-stain technique is described in the Procedure part of this handout; however, it is important to recognize early on that two aspects of the procedure are crucial: 1. The crystal violet treatment must precede iodine treatment. Iodine acts as a mordant, i.e., it increases the affinity of the cells for the crystal violet. Iodine alone has no bacterial staining capabilities. 2. Decolorization must be short and precise. Too long an exposure to 95% alcohol will decolorize Gram-positive as well as Gram-negative cells. The Gram stain has been used as a taxonomic tool for many years, aiding in the classification and identification of bacterial cells. However, it is also useful in a broader sense, as there appears to be a close correlation between the Gram reaction and many other morphological and physiological characteristics of bacterial cells.
    [Show full text]
  • STAINING TECHNIQUES — Staining Is an Auxiliary Technique Used in Microscopy to Enhance Contrast in the Microscopic Image
    STAINING TECHNIQUES Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains or dyes are used in biology and medicine to highlight structures in biological tissues for viewing with microscope. Cell staining is a technique that can be used to better visualize cells and cell components under a microscope. Using different stains, it is possible to stain preferentially certain cell components, such as a nucleus or a cell wall, or the entire cell. Most stains can be used on fixed, or non-living cells, while only some can be used on living cells; some stains can be used on either living or non-living cells. In biochemistry, staining involves adding a class specific (DNA, lipids, proteins or carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. Staining and fluorescence tagging can serve similar purposes Purposes of Staining The most basic reason that cells are stained is to enhance visualization of the cell or certain cellular components under a microscope. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample. Cells may also be enumerated by staining cells to determine biomass in an environment of interest. Stains may be used to define and examine bulk tissues (e.g. muscle fibers or connective tissues), cell populations (different blood cells) or organelles within individual cells. Biological staining is also used to mark cells in flow cytometry, flag proteins or nucleic acids on gel electrophoresis Staining is not limited to biological materials, it can also be used to study the morphology (form) of other materials e.g.
    [Show full text]
  • Enrichment, Isolation and Characterization of Phenazine-1-Carboxylic Acid (PCA)-Degrading Bacteria Under Aerobic and Anaerobic Conditions
    Enrichment, isolation and characterization of phenazine-1-carboxylic acid (PCA)-degrading bacteria under aerobic and anaerobic conditions Miaomiao Zhang A thesis in fulfilment of the requirements for the degree of Doctor of Philosophy School of Civil and Environmental Engineering Faculty of Engineering September, 2018 THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: ZHANG First name: Miaomiao Other name/s: Abbreviation for degree as given in the University calendar: PhD School: Civil and Environmental Engineering Faculty: Engineering Title: Enrichment, isolation and characterization of phenazine-1- carboxylic acid (PCA)-degrading bacteria under aerobic and anaerobic conditions Abstract Phenazines are a large class of nitrogen-containing aromatic heterocyclic compounds produced and secreted by bacteria from phylogenetically diverse taxa under aerobic and anaerobic conditions. Phenazine-1-carboxylic acid (PCA) is regarded as a ‘core’ phenazine because it is transformed to other phenazine derivatives. Due to their important roles in ecological fitness, biocontrol of plant pathogens, infection in cystic fibrosis and potential in anticancer treatments, understanding the fate of phenazine compounds is prudent. Only seven bacterial species are known to degrade phenazines and all of them are aerobic. Hence, the aim of this study is to enrich, isolate and characterize additional bacteria with the ability to degrade phenazines aerobically and anaerobically. In this study, the isolation of a PCA-degrading Rhodanobacter sp. PCA2 belonging to Grammaproteobacteria is reported. Characterization studies revealed that strain PCA2 is also capable of transforming other phenazines including phenazine, pyocyanin and 1-hydroxyphenazine. The sequencing, annotation and analysis of the genome of strain PCA2 revealed that genes (ubiD and the homolog of the MFORT_16269 gene) involved in PCA degradation were plasmid borne.
    [Show full text]