Academic literature on the topic 'Lead (II) compounds'
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Journal articles on the topic "Lead (II) compounds"
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Jones, Jamie N., and Alan H. Cowley. "π-Indenyl tin(ii) and lead(ii) compounds." Chem. Commun., no. 10 (2005): 1300–1302. http://dx.doi.org/10.1039/b410549d.
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Wang, Yin, Yanjiao Xie, Wenlu Li, Zimeng Wang, and Daniel E. Giammar. "Formation of Lead(IV) Oxides from Lead(II) Compounds." Environmental Science & Technology 44, no. 23 (December 2010): 8950–56. http://dx.doi.org/10.1021/es102318z.
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Harrowfield, JM, H. Miyamae, BW Skelton, AA Soudi, and AH White. "Lewis-Base Adducts of Lead(II) Compounds. XVI. Synthetic and Structural Studies of Some Adducts of 2-Aminomethylpyridine With Lead(II) Compounds." Australian Journal of Chemistry 49, no. 10 (1996): 1127. http://dx.doi.org/10.1071/ch9961127.
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Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 2:1 adducts of 2-aminomethylpyridine ('amp') with lead(II) nitrate and thiocyanate . [(amp)2Pb(NO3)2]2 is triclinic, Pī, a 11.616(4), b 11.145(6), c 7.341(3) Ǻ, α 83.87(4), β 89.17(3), γ 64.12(3)°, Z = 1 dimer ; R was 0.043 for No 3529 independent 'observed' (I > 3σ(I)) reflections. [(amp)2Pb(SCN)2]2 is also triclinic, Pī , a 12.121(9), b 9.301(14), c 8.615(8) Ǻ, α 70.11(10), β 84.00(7), γ 79.38(10)°, Z = 1 dimer (R 0.033 for No 3467). Both complexes are centrosymmetric dimers ; the coordination environment is made up in each case of a pair of N,N°-bidentate bases, one terminally bound anion (O,O°-chelating nitrate or S-bonded thiocyanate ) and bridging anions. In the case of the thiocyanates, these bridge end-on, so that the lead(II) environment is seven-coordinate PbN5S2; in the nitrate, the anion chelates through two of its oxygen atoms, bridging via the third, so that the lead(II) environment is nine-coordinate PbN4O5. A 'problem structure', [(amp)2Pb(ClO4)2], monoclinic, C2/c (?), a 14.528(3), b 8.203(3), c 15.495(6) Ǻ, β 91.14(3)°, Z = 4 f.u ., R 0.044 for No 1775, is also recorded, the crystal seemingly a disordered aggregate of [(N, N′-amp)2Pb(OClO3)2] moieties.
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Han, Kyoung R., Hee Jin Koo, and Chang Sup Lim. "Novel Route to Lead-Based Ferroelectric Compounds via Tetragonal Lead(II) Oxide Intermediates." Journal of the American Ceramic Society 83, no. 9 (December 20, 2004): 2214–18. http://dx.doi.org/10.1111/j.1151-2916.2000.tb01537.x.
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Bowes, Scott, Dongyu Sun, Azita Kaffashan, Chenhui Zeng, Claudio Chuaqui, Xiaoping Hronowski, Alex Buko, Xin Zhang, and Serene Josiah. "Quality Assessment and Analysis of Biogen Idec Compound Library." Journal of Biomolecular Screening 11, no. 7 (September 14, 2006): 828–35. http://dx.doi.org/10.1177/1087057106290993.
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A subset of the compound repository for lead identification at Biogen Idec was characterized for its chemical stability over a 3-year period. Compounds were stored at 4 °C as 10 mM DMSO stocks, and a small subset of compounds was stored as lyophilized dry films. Compound integrity of 470 discrete compounds (Compound Set I) and 1917 combinatorial chemistry-derived compounds (Compound Set II) was evaluated by liquid chromatography/mass spectrometry from the time of acquisition into the library collection and after 3 years of storage. Loss of compound integrity over the 3 years of storage was observed across the 2 subsets tested. Of Compound Set I, 63% of samples retained > 80% purity, whereas 57% of samples from Compound Set II had purity greater than 60%. The stability of the lyophilized samples was superior to the samples stored as DMSO solution. Although storage at 4 °C as DMSO solution was adequate for the majority of compounds, the authors observed and quantified the level of degradation within the compound collection. Their study provides general insight into compound storage and selection of library subsets for future lead identification activities.
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Mbuyazi, Thandi B., and Peter A. Ajibade. "Bis(4-methylpiperidine-1-carbodithioato)-lead(II) and Bis(4-benzylpiperidine-1-carbodithioato)-lead(II) as Precursors for Lead Sulphide Nano Photocatalysts for the Degradation of Rhodamine B." Molecules 26, no. 23 (November 29, 2021): 7251. http://dx.doi.org/10.3390/molecules26237251.
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Bis(4-methylpiperidine-1-carbodithioato)-lead(II) and bis(4-benzylpiperidine-1-carbodithioato)-lead(II) were prepared and their molecular structures elucidated using single crystal X-ray crystallography and spectroscopic techniques. The compounds were used as precursors for the preparation of lead sulphide nano photocatalysts for the degradation of rhodamine B. The single crystal structures of the lead(II) dithiocarbamate complexes show mononuclear lead(II) compounds in which each lead(II) ion coordinates two dithiocarbamato anions in a distorted tetrahedral geometry. The compounds were thermolyzed at 180 ℃ in hexadecylamine (HDA), octadecylamine (ODA), and trioctylphosphine oxide (TOPO) to prepare HDA, ODA, and TOPO capped lead sulphide (PbS) nanoparticles. Powder X-ray diffraction (pXRD) patterns of the lead sulphide nanoparticles were indexed to the rock cubic salt crystalline phase of lead sulphide. The lead sulphide nanoparticles were used as photocatalysts for the degradation of rhodamine B with ODA-PbS1 achieving photodegradation efficiency of 45.28% after 360 min. The photostability and reusability studies of the as-prepared PbS nanoparticles were studied in four consecutive cycles, showing that the percentage degradation efficiency decreased slightly by about 0.51–1.93%. The results show that the as-prepared PbS nanoparticles are relatively photostable with a slight loss of photodegradation activities as the reusability cycles progress.
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Akbari Afkhami, Farhad, Ghodrat Mahmoudi, Fengrui Qu, Arunava Gupta, Muhammet Köse, Ennio Zangrando, Fedor I. Zubkov, Ibon Alkorta, and Damir A. Safin. "Supramolecular lead(ii) architectures engineered by tetrel bonds." CrystEngComm 22, no. 13 (2020): 2389–96. http://dx.doi.org/10.1039/d0ce00102c.
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The structures, including tetrel bonding, of PbII coordination compounds assembled from N′-(pyridin-2-ylmethylene)picolinohydrazide, N′-(pyridin-2-ylmethylene)nicotinohydrazide and N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide ligands are discussed.
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Bhattacharya, Sagarika, and Sasankasekhar Mohanta. "Heterometallic copper(II)–lead(II), nickel(II)–lead(II) and copper(II)–indium(III) compounds derived from an acyclic double-compartment Schiff base ligand." Inorganica Chimica Acta 432 (June 2015): 169–75. http://dx.doi.org/10.1016/j.ica.2015.03.041.
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Singh, R. V., S. C. Joshi, Shalini Kulshrestha, Pooja Nagpal, and Anil Bansal. "Antiandrogen and Antimicrobial Aspects of Coordination Compounds of Palladium(II), Platinum(II) and Lead(II)." Metal-Based Drugs 8, no. 3 (January 1, 2001): 149–58. http://dx.doi.org/10.1155/mbd.2001.149.
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Synthesis, characterization and antimicrobial activities of an interesting class of biologically potent macrocyclic complexes have been carried out. All the complexes have been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trails and biochemical parameters of reproductive organs have been examined and discussed. The resulting biologically active [M(MaLn)(R2)]Cl2 and [Pb(MaLn)(R2)X2] (where, M = PdII or PtII and X = Cl or NO3) type of complexes have been synthesized by the reactions of macrocyclic ligands (MaLn) with metal salts and different diamines in 1:1:1 molar ratio in methanol. Initially the complexes were characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding was established on the basis of IR, H1 NMR, C13 NMR, Pt195 NMR, Pb207 NMR, XRD and electronic spectral studies. The macrocyclic ligand coordinates through the four azomethine nitrogen atoms which are bridged by benzil moieties. IR spectra suggest that the pyridine nitrogen is not coordinating. The palladium and platinum complexes exhibit tetracoordinated square-planar geometry, whereas a hexacoordinated octahedral geometry is suggested for lead complexes.
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Leung, Wing-Por, Ka-Po Chan, Kwok-Wai Kan, and Thomas C. W. Mak. "Synthesis of Heteroleptic Tin(II) and Lead(II) Compounds from Pyrazyl-Linked Bisphosphoranoimine." Organometallics 27, no. 12 (June 2008): 2767–73. http://dx.doi.org/10.1021/om800104x.
Full textDissertations / Theses on the topic "Lead (II) compounds"
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Johnston, Simon Richard. "Characterisation of basic lead(II) and tin(II) compounds from aqueous systems." Thesis, Brunel University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294510.
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Caiazza, Daniela. "Crown ethers as potential lead (II) specific probes : a thesis submitted for the degree of Doctor of Philosophy /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phc1328.pdf.
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Abdelhamid, Dalia. "Natural Products as Lead Compounds for Drug Development. Part I: Synthesis and Biological Activity of a Structurally Diverse Library of Curcumin Analogues. Part II: Synthesis of Novel Sterol Natural Products and Related Analogues as Antileishmanial Ag." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299685922.
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Diantouba, Bertin Aimé. "Effets structuraux des acyl-4-pyrazolones-5 dans l'extraction liquide-liquide des cations metalliques divalents." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13093.
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Etude de l'effet de l'acidite de la lipophilie et effets structuraux des acyl-4 pyrazolones-5 dans l'extraction de cu, co, zu et pb divalents. Extraction de 3 types de complexes metalliques : mononucleaires de type m(l-n-lh)::(2) ou m(l-n-l) et polynucleaires (m(l-n-l))::(j). Meilleures possibilites des bis-acyl-4 pyrazolones-5
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Cohanoschi, Mihaela. "Part I: Evaluation of Russian Synthetic Compounds as a Potential Source of New Drug Leads Agains Breast and Colon Cancer Part II: Isolation of Beta-Amyrin Formate From Eucalyptus Viminalis Labill and Investigation of its Colon Cancer Activity." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4144.
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Although modern medicine made great steps toward curing most diseases considered deadliest, yet cancer remains one of the major public health problems. The first part of this thesis investigates a new source of selective compounds that are potential candidates against cancer. Fifteen Russian compounds were tested in order to establish their efficiency against two types of cancer: human breast SK-Br-3 and colorectal carcinoma HT-29. The bioassay results show that seven of the new synthetic Russian compounds can be considered new drug leads, based upon their low toxicity and efficacy in slowing the growth of human breast cancer and colon cancer cells. The goal of the second part of the thesis was to isolate pure compounds that inhibit the growth of cancer cells from the methylene chloride extract of Eucalyptus viminalis Labill. This plant was selected for investigations since a preliminary screening of plants from Russia indicated that had activity against cancer. The result of this work was the isolation of a pure compound which has been analyzed using different spectroscopic techniques such as MS, HPLC, 1H-NMR, DEPT, 13C-NMR. The extracted compound was â-amyrin formate, which was previously reported by Malhotra,[49] from Canarium strictum Gum in 1987. Also, the bioassay results indicated that â-amyrin formate might be considered a possible drug lead against colon cancer and can be recommended for further investigations. This is the first report of isolation of â-amyrin formate from Eucalyptus viminalis Labill and the first test of the activity of this compound against colon cancer.M.S.
Department of Chemistry
Arts and Sciences
Industrial Chemistry
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Caiazza, Daniela. "Crown ethers as potential lead (II) specific probes : a thesis submitted for the degree of Doctor of Philosophy / by Daniela Caiazza." Thesis, 1999. http://hdl.handle.net/2440/19405.
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Errata pasted onto front end-paper.Bibliography: leaves 173-188.
xii, 188 leaves : ill. (chiefly col.) ; 30 cm.
Describes a comprehensive study of a select but informative set of crown ether ligands that may potentially be used in the development of a fluorescent lead (II) specific probe.
Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999
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"Part I, total synthesis of (±)-pallambins C and D: and, Part II, gold-catalyzed tandem cyclization towards substituted bicyclo[3.2.1]octenone derivatives : lead to total synthesis of dhilirolides A-D." 2013. http://library.cuhk.edu.hk/record=b5549785.
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半日花烷型二萜天然產物 pallambins A-D 是從中國苔植物Pallavicinia ambigua 中分獲取的，這二萜中的許多化合物都呈現出有趣的生物活性。從分子結構觀點看，pallambins C 和D 由獨特的梯型[6-5-5-5]四環骨架構成，該分子骨架中包含7 個毗的體中心及三烯部分。並且，二環[3.2.1]辛烷酮片段的橋接部分分別由個橋頭甲基以及橋中的乙烯基密集取代。該分子的骨架新穎性及潛在的生物活性激發我們去進相關的全合成探。在此，我們將報導pallambins C 和D 的首次全合成。本文第一章首先概述pallavicinin 系的天然源，結構特點以及生物學效用。此外，重點介紹pallambins C 和D 的分，結構鑒定以及反合成分析。
第二章討消旋體pallambins C 和D 的全合成細節。該合成以消旋Wieland-Miescher ketone (WMK)為起始原，經38 步線性步驟得到最終產物。該合成線突出以下個重要的化學轉化：a) 一個由Grob 碎及分子內aldol成環反應組成的多米式程，構建目標分子內關鍵的二環[3.2.1]辛烷酮單元；b) 一個由脲/鈀體系催化的烷氧羰基化增環反應，構建稠環型四氫呋喃/γ 內酯雙環框架。
第三章總結本文的相關研究工作。
第四章給出相關工作的詳細實驗據。
Naturally occurring pallambins A-D isolated from the Chinese liverwort Pallavicinia ambigua are classified as modified labdane-type diterpenoids, many of which exhibit interesting biological activities. From a structural perspective, pallambins C and D are consisting of trienes and an unprecedented ladder-shaped [6-5-5-5] tetracyclic skeleton bearing seven contiguous stereogenic centers. Furthermore, the bridge of the bicyclo[3.2.1]octane segment is densely substituted with two methyl groups on the bridge-heads and a vinyl group on the carbon bridge. The skeletal novelty and potential bioactivities of pallambins C and D inspired us to explore their total synthesis. In this thesis, the first total synthesis of (±)-pallambins C and D is described.
In Chapter 1, a general introduction to the natural occurrence, structural features and biological potency of pallavicinin family is presented briefly. In addition, the background of pallambins C and D including isolation, structural elucidation and retrosynthetic analysis is emphasized.
In Chapter 2, detailed synthesis of (±)-pallambins C and D involving a linear 38 steps starting from the known (±)-Wieland-Miescher ketone is discussed. The synthetic approach features the following two key conversions: a) a domino process including Grob fragmentation and intramolecular aldol cyclization to build up the bicyclo[3.2.1]octanone embedded in the target molecules; b) a thiourea/palladium-catalyzed alkoxycarbonylative annulation to assemble the fused tetrahydrofuran/γ-lactone bicyclic framework.
Chaper 3 provides a conclusion of this research work.
Chapter 4 is concerned with the experimental details.
[With images.]
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Xu, Xuesong.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references.
Abstracts also in Chinese.
ACKNOWLEDGEMENTS --- p.I
CONTENTS --- p.II
ABBREVIATIONS --- p.V
PART I:
ABSTRACT --- p.1
Chapter CHAPTER 1. --- INTRODUCTION
Chapter 1.1 --- General background --- p.4
Chapter 1.1.1 --- General introduction to liverworts --- p.4
Chapter 1.1.2 --- General introduction to terpenoids in liverworts --- p.5
Chapter 1.2 --- Introduction to pallavicinin family --- p.9
Chapter 1.2.1 --- Isolation and structural elucidation of pallavicinin compounds --- p.9
Chapter 1.2.2 --- Synthetic advances on pallavicinin family --- p.13
Chapter 1.3 --- Introduction to the present research --- p.16
Chapter 1.3.1 --- Structural elucidation and features of pallambins C and D --- p.16
Chapter 1.3.2 --- Biogenetic hypothesis and retrosynthetic analysis of pallambins C and D --- p..20
Chapter 1.4 --- Aim of the present work --- p.22
Chapter CHAPTER 2. --- RESULTS AND DISCUSSION --- p.24
Chapter 2.1 --- Previous synthetic effort on pallambin D (2) --- p.24
Chapter 2.2 --- Successful synthetic approach to 1 and 2 --- p.25
Chapter 2.2.1 --- Synthesis of compound 24 --- p.25
Chapter 2.2.2 --- Synthesis of compound 14 --- p.30
Chapter 2.2.3 --- Synthesis of compound 13 --- p.37
Chapter 2.2.4 --- Synthesis of compound 12 --- p.43
Chapter 2.2.5 --- Synthesis of 1 and 2 --- p.53
Chapter CHAPTER 3. --- CONCLUSION --- p.60
Chapter CHAPTER 4. --- EXPERIMENTAL SECTION --- p.62
REFERENCES --- p.104
PART II:
ABSTRACT --- p.110
Chapter CHAPTER 1. --- INTRODUCTION --- p.113
Chapter 1.1 --- Introduction to bicyclo[3.2.1]octane skeleton --- p.113
Chapter 1.1.1 --- Structural features of bicyclo[3.2.1]octane --- p.113
Chapter 1.1.2 --- Bicyclo[3.2.1]octane-containing bioactive natural products --- p.114
Chapter 1.1.3 --- Methodologies for synthesis of bicyclo[3.2.1]octane derivatives --- p.116
Chapter 1.1.4 --- Gold-catalyzed construction of bicyclo[3.2.1]octane unit --- p.117
Chapter 1.2 --- Background of the present research --- p.119
Chapter 1.2.1 --- Introduction to dhilirolides A-D --- p.119
Chapter 1.2.2 --- Retrosynthetic analysis of dhilirolide A (1) --- p.121
Chapter 1.3 --- Aim of the present work --- p.122
Chapter CHAPTER 2. --- RESULTS AND DISCUSSION --- p.124
Chapter 2.1 --- Synthesis of the key acetal allene precursor 6 --- p.124
Chapter 2.1.1 --- Preparation of the starting dimethoxyl ketone 7 --- p.124
Chapter 2.1.2 --- Preparation of alkynyl furan 11 --- p.126
Chapter 2.1.3 --- Preparation of acetal allene 6 --- p.128
Chapter 2.2 --- Synthesis of bicyclo[3.2.1]octenone derivative 5 --- p.134
Chapter 2.3 --- Synthesis of mono-tosylate 26 --- p.138
Chapter CHAPTER 3. --- CONCLUSION --- p.141
Chapter CHAPTER 4. --- EXPERIMENTAL SECTION --- p.143
REFERENCES --- p.162
APPENDIX --- p.167
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劉俊呈. "Finding The Lead Compounds to Suppress Protein Tyrosine Phosphatase 1B for treating Type II Diabetes by Virtual High Throughput Screening and Pharmacophore Scoring Method." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/36958358785507005380.
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碩士國立清華大學
分子醫學研究所
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The research on the knock-out studies in mice manifests that the insulin resistance in those mice lacking for PTP1B protein would evidently increases and possesses the certain resistivity against obesity. Consequently, PTP1B is considered as the target for medicine designed to treat for Type II diabetes. With the progress in computational science, it is gradually becoming a trend to utilize the virtual screening method to accelerate the R&D in medication and effectively shorten the time and expense of R & D. In fact, there are not a few successful examples applied in foreign pharmacists. This experiment is in regard to adopting direct and indirect drug methods to screen the available inhibitor for PTP1B. First, it’s to find out the reasonable parameter computed through “DOCK” software of direct drug method towards the PTP1B receptor, the model based on the aforementioned parameter, which correlation can reach 0.79 in the activity ranks of inhibitor, then to proceed the virtual screening in “Maybridge” chemistry database. On the other hand, to establish the pharmacoophore which the so-called “Catalyst” indirect drug method software applied in screening PTP1B inhibitor, then reaching 0.976 correlation and 0.868 rms following this step, to make the activity predict on the compound screened by the DOCK software. In addition to this, assorting with two scoring function in terms of XScore and PScore, and the screening method of hydrogen bond, at last select 165 most potential lead compounds of PTP1B.
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DiDonato, Dana A. "Part I. design and synthesis of prototypes as leads on a compound library aimed at plasmepsin ii inhibition. Part II. synthesis and evaluation of modified nucleotides for dna aptamer selection." 2006. http://www.lib.ncsu.edu/theses/available/etd-08042006-151854/unrestricted/etd.pdf.
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Wang, Ying-Lien, and 王櫻璉. "(I) The Design and Synthesis of Benzimidazole and Dihydroquinazolines Derivatives Based on Lead Compound (II) Ruthenium-Catalysed C-H activation to the Synthesis of [4,5]imidazo[2,1-a]isoindole Derivatives." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/71056344608467361199.
Full textBooks on the topic "Lead (II) compounds"
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Dub, Michael. Organometallic Compounds Literature Survey 1937-1958: Volume II Organic Compounds of Germanium, Tin and Lead. Springer London, Limited, 2013.
Find full textBook chapters on the topic "Lead (II) compounds"
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Huber, F., and K. Grätz. "From Lead(II) Compounds with Organoalkali Reagents." In Inorganic Reactions and Methods, 214. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145258.ch67.
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Crisp, G. T. "Using Magnesium and Lead(II) Bromide." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00467.
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Guiry, P. J., and P. J. McCormack. "Reaction of Halotriorganoplumbanes with Lead(II) Thiolates." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00710.
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"20. Introduction of Fluorine with Lead(II) Fluoride and Organolead Fluorides." In Organo-Fluorine Compounds, edited by Baasner, Hagemann, and Tatlow. Stuttgart: Georg Thieme Verlag, 1998. http://dx.doi.org/10.1055/b-0035-111184.
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Eagle, P. A. C. "Tetrabenzylplumbanes from Lead(II) Chloride and Benzylmagnesium Halides." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00804.
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Eagle, P. A. C. "From Lead(II) Chloride, Grignard Reagents, and Allyl Halides." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00811.
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Emsley, John. "Lead murders." In The Elements of Murder. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780192805997.003.0021.
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Criminal poisonings with lead compounds are noteworthy because of their rarity. Indeed a person intent on poisoning someone would be unlikely to choose lead because of its uncertainty of action. Nevertheless there were murders in which it was used, such as the killing of Thomas Taylor in September 1858, when white lead was the poison, and the murder of Mary Ann Tregillis in 1882, when lead acetate was used. This salt was also the agent in the attempted murder of Honora Turner also in 1858. The lead compound that killed Pope Clement II in 1047 can only be speculated on. The inquest into the death of Thomas Taylor, which was held by the coroner for Gloucestershire on 27 September 1858, was reported in the November issue of the Pharmaceutical Journal because it was an unusual case of death by poisoning with lead carbonate. Thomas lived in Gloucestershire with his wife, Ann, and the child that he had fathered by another woman. He also had a brother, Charles, who had recently been released from prison and who had gone to live with the Taylors. It was not long before quarrels broke out between Thomas and his wife, whom he accused of being too affectionate towards Charles. In fact Ann was more than affectionate; she openly stated that she preferred brother Charles and wished her husband was dead. Her wish was to be granted. In August 1858 Thomas was seized with violent pains in his stomach which lasted for several days and for which he sought medical treatment. The doctor gave him some opium pills to kill the pain and senna water to act as a laxative. When these failed to cure him his doctor prescribed larger doses which he said could be obtained from his surgery. However, the doctor noticed that when his wife Ann went to collect more senna water she brought along a bottle that had contained the original medicine and that the dregs of the first dose were now a different colour and it tasted odd. Thomas died on 4 September, but the doctor was sufficiently suspicious of the cause of death that he refused to issue a death certificate until he and a surgeon friend of his had carried out a post-mortem.
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Eagle, P. A. C. "Benzylplumbanes from Lead(II) Chloride, Arylmagnesium Bromides, and Benzyl Halides." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00805.
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Eagle, P. A. C. "Alkyl(trivinyl)plumbanes from Lead(II) Chloride by Reactions with Vinylmagnesium Halides and Haloalkanes." In Compounds of Group 14 (Ge, Sn, Pb), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-005-00796.
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Koli, Preeti, and Rajesh K. Singh. "Progress in Nitrogen and Sulphur-based Heterocyclic Compounds for their Anticancer Activity." In Key Heterocyclic Cores for Smart Anticancer Drug–Design Part II, 79–104. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815040043122020006.
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Cancer is a widespread disease worldwide. Researchers and scientists have been giving much attention to the drug design and drug discovery of nitrogen (N) and sulfur (S)-based heterocyclic compounds in the last decade. These heteroatoms containing heterocyclic compounds have an imperative role in medicinal chemistry in developing new anticancer drugs. These N and S-based heterocyclic compounds such as pyrrole, quinazoline, thiadiazole, and quinoline are widely used in the rational drug design for anticancer drugs with a favorable therapeutic index. They inhibit the cancerous cells by different mechanisms like inhibiting FGFR, VEGFR, EGFR receptors and inducing apoptosis. They also act as a tyrosine kinase inhibitor, dihydrofolate reductase inhibitor, pancreatic ductal adenocarcinoma inhibitor, and PI3K inhibitor. This chapter highlights the SAR study of recent literature (2016-2020) in which N and S heterocyclic compounds are present as core structures in molecules. This chapter also emphasizes the benefits of hybrid molecules acting on multiple target mechanisms. In the future, N and S- based heterocyclic compounds will be essential lead compounds for the designing of new anticancer drugs.
Conference papers on the topic "Lead (II) compounds"
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Ouvaroff, A. A., I. A. Butko, and N. A. Litova. "Physico-chemical properties and ecological aspect of crystalline iron (III) orthovanadate, iron (III), copper (II) and lead (II) metavanadate." In III All-Russian Scientific Conference with International Participation "Science, technology, society: Environmental engineering for sustainable development of territories". Krasnoyarsk Science and Technology City Hall, 2022. http://dx.doi.org/10.47813/nto.3.2022.6.125-136.
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In the work, iron (III) orthovanadate, iron (III), copper (II) and lead (II) metavanadates were obtained, the ratio of the obtained substances to concentrated acids – sulfuric, hydrochloric, nitric and orthophosphoric, alkalis, aqueous solutions of chlorine, bromine and iodine, some chalcogens, aluminum and magnesium oxides was studied. Melting temperatures, densities of crystalline substances, solubility in water have been experimentally determined. IR spectroscopic analysis of compounds by the method of disturbed total internal reflection was carried out for the first time. Based on the data obtained, conclusions are drawn about the structure and chemical properties of substances, as well as the most dangerous compounds obtained by interacting with acids, alkalis and halogens.
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Jain, Sukriti, and Pritpal Singh. "Electrodeposition and Characterization of Very Thin Film II-VI Compounds for Novel Superlattice Solar Cells." In ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90239.
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Thin films of lead telluride (PbTe) and zinc telluride (ZnTe) have been electrodeposited on indium tin oxide (ITO)-coated glass substrates. Uniform dense films of ∼ 100 nm have been obtained for both materials. The electrochemical deposition procedures for fabricating these films are described. The as-deposited films have been characterized by scanning electron microscopy, energy dispersive spectroscopy, and optical absorption spectrophotometry. Multi layer structures, up to 3 layers, of ZnTe/PbTe films, have been fabricated.
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Chan, Kwai S., Michael P. Enright, and Jonathan P. Moody. "Development of a Probabilistic Methodology for Predicting Hot Corrosion Fatigue Crack Growth Life of Gas Turbine Engine Disks." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95057.
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Advanced Ni-based gas turbine disks are expected to operate at higher service temperatures in aggressive environment for longer time durations. Exposures of Ni-based alloys to alkaline-metal salts and sulfur compounds at elevated temperatures can lead to hot corrosion fatigue crack growth in engine disks. Type II hot corrosion involves the formation and growth of corrosion pits in Ni-based alloys at a temperature range of 650°C to 750°C. Once formed, these corrosion pits can serve as stress concentration sites where fatigue cracks can initiate and propagate to failure under subsequent cyclic loading. In this paper, a probabilistic methodology is developed for predicting the corrosion fatigue crack growth life of gas turbine engine disks made from a powder-metallurgy Ni-based superalloy (ME3). Key features of the approach include (1) a pit growth model that describes the depth and width of corrosion pits as a function of exposure time, (2) a cycle-dependent crack growth model for treating fatigue, and (3) a time-dependent crack growth model for treating corrosion. This set of deterministic models is implemented into a probabilistic life-prediction code called DARWIN. Application of this approach is demonstrated for predicting corrosion fatigue crack growth life in a gas turbine disk based on ME3 properties from the literature. The results of this study are used to assess the conditions that control the transition of a corrosion pit to a fatigue crack, and to identify the pertinent material parameters influencing corrosion fatigue life and disk reliability.
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Грешников, Э. А., А. А. Демкив, А. Н. Артемьев, Р. Д. Светогоров, Н. Н. Колобылина, А. Д. Беляев, А. А. Калоян, et al. "STUDIES OF THE PEGTYMEL PETROGLYPHS, BASED ON A COMPLEX OF NATURAL-SCIENTIFIC METHODS IN THE NATIONAL RESEARCH CENTRE “KURCHATOV INSTITUTE”." In Труды Сибирской Ассоциации исследователей первобытного искусства. Crossref, 2019. http://dx.doi.org/10.25681/iaras.2019.978-5-202-01433-8.59-69.
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В НИЦ Курчатовский институт с использованием комплекса естественнонаучных методов исследован камень с выбитыми изображениями, найденный на р. Пегтымель на Чукотке археологической экспедицией ИА РАН под руководством Е.Г.Дэвлет. Установлены состав и природа минеральных образований на поверхности камня с петроглифами. Выявлен скальный загар , содержащий марганец и потенциально пригодный для датирования. На карте распределения химических элементов в выбивке зафиксированы медь и цинк и предположено их антропогенное происхождение в качестве микрочастиц древнего орудия. Намечена возможная дата создания петроглифов: конец II начало I тыс. до н.э. Подтверждена версия исследователей петроглифов Пегтымеля о том, что рисунки на скалах выбивались металлическими орудиями. Several separated stone blocks with pecked images had been found in the course of the expedition for study the rock art site at the Pegtymel River in the western part of the Chukotka Peninsula. The expedition (2005 2008) was organized by the Institute of Archaeology and lead by Ekaterina Devlet. One of such blocks was taken away from the site to Moscow, which made it possible to carry out recently its study in the Kurchatov Institute with the use of a whole complex of natural-scientific methods. The researchers have identified mineral compounds on the surface of the decorated rock and determined the rock varnish formation on it. Cu Zn particles have been detected in the pecked area. It is possible that the particles were introduced as a result of processing the rock with bronze or brass tool. The date of creation the petroglyphs is proposed as the end of the 2nd beginning of the 1st millennium BC.
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Sabliy, Larisa, Veronika Zhukova, and Lyubov Kika. "Effective Biological Treatment of Tannery Wastewater from Nitrogen Compounds." In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.ii.22.
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Even after using physico-chemical and biological methods, tannery wastewater still contains a large amount of nitrogen compounds, which reaches 90 mg/dm3. The ingress of such wastewater into natural reservoirs leads to eutrophication. The goal is to determine the efficiency of nitrogen compounds removal during sequential wastewater treatment in anaerobic, anoxic and aerobic bioreactors with immobilized microorganisms. For the study, wastewater from a tannery, collected after cleaning in aeration tanks, was used. Model solutions with a concentration of 18.4 - 90 mg/ dm3 were obtained by dilution. 5 sequential bioreactors were used - anaerobic (2 stages), anoxic (2 stages) and aerobic (1 stage) with a capacity of 125 ml/h. Microorganisms were immobilized in each bioreactor on artificial carrier. The effects of organic nitrogen removal in anaerobic bioreactors were 58-66%, anoxic 51-70%, aerobic 57, 5%. A decrease in the concentration of nitrogen compounds occurs as a result of the formation of N2, NH3 gases and the use of nitrogen by microorganisms for biomass growth. It is proposed that sequential treatment of tannery wastewater in anaerobic, anoxic, and aerobic conditions with immobilized microorganisms made it possible to obtain a high degree of nitrogen removal. The method does not require chemical materials and is ecological.
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Pan, T. S., and S. S. Rao. "Fault Tree Approach for the Reliability Analysis of Gear Trains: Part II — Example Applications." In ASME 1987 Design Technology Conferences. American Society of Mechanical Engineers, 1987. http://dx.doi.org/10.1115/detc1987-0036.
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Abstract The application of fault tree techniques to the analysis of gear trains is considered. The techniques involve the decomposition of the system into a logic diagram or fault tree in which certain basic or primary events lead to a specified top event which signifies the total failure of the system. The fault trees are used to obtain minimal cut sets from which the modes of system failure and hence the reliability measure for the top event can be calculated. The method of constructing fault trees and the subsequent estimation of reliability of the system is illustrated through a nine speed compound gear train and a five speed epicyclic gear train.
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Petrović, Biljana. "TRANSITION METAL ION COMPLEXES AS POTENTIAL ANTITUMOR AGENTS." In 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac,, 2021. http://dx.doi.org/10.46793/iccbi21.009p.
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Discovery of the antitumor activity of platinum complex, cisplatin, cis-Pt(NH3)2Cl2, and later carboplatin and oxaliplatin, led to the intensive investigation of the potential antitumor activity of the huge number of platinum complexes. Furthermore, it is well-known that platinum complexes express toxicity, numerous side effects and resistance, so the scientists make a lot of efforts to synthetize, beside Pt(II) and Pt(IV), other non-platinum compounds with potential antitumor activity, such as Pd(II), Ru(II/III) and Au(III) complexes. The goal of this study is to summarize the results of the investigation of the interactions between some mononuclear, homo- and hetero-polynuclear Pt(II), Pd(II), Ru(II/III) and Au(III) complexes with different sulfur- and nitrogen-donor biologically relevant nucleophiles. Among mononuclear complexes, the compounds with aromatic terpy (tepyridine) or bpma (bis-(2- pyridylmethyl)amine) and aliphatic dien (diethylentriamine) nitrogen-containing inert ligands were studied. Different homo- and hetero-polynuclear complexes with pz (pyrazine) or 4,4’-bipy (4,4’- bipyridine) as bridging and mostly en (ethylenediamine), bipy (2,2’-bipyridine) and dach (trans-1,2- diaminocyclohexane) as inert ligands were studied as well. The research was focused on the connection between the structure and the mechanisms of interactions with different biomolecules, such as L- cysteine (L-Cys), L-methionine (L-Met), tripeptide glutathione (GSH), guanosine-5’-monophosphate (5’-GMP), DNA and bovine serum albumin (BSA). Some of these complexes were selected for in vitro studies of the cytotoxicity on different tumor cell lines. Observed results contribute a lot as a guidance for the future design and determination of the structure-activity relationship (SAR) of different transition metal ion complexes.
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McGovern, Kevin T., and James H. Leylek. "A Detailed Analysis of Film Cooling Physics: Part II — Compound–Angle Injection With Cylindrical Holes." In ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-gt-270.
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Detailed analyses of computational simulations with comparisons to experimental data were performed to identify and explain the dominant flow mechanisms responsible for film cooling performance with compound angle injection, Φ, of 45°, 60°, and 90°. A novel vorticity and momentum based approach was implemented to document how the symmetric, counter–rotating vortex structure typically found in the crossflow region in streamwise injection cases, becomes asymmetric with increasing Φ. This asymmetry eventually leads to a large, single vortex system at Φ = 90° and fundamentally alters the interaction of the coolant jet and hot crossflow. The vortex structure dominates the film cooling performance in compound angle injection cases by enhancing the mixing of the coolant and crossflow in the near wall region, and also by enhancing the lateral spreading of the coolant. The simulations consist of fully–elliptic and fully–coupled solutions for field results in the supply plenum, film–hole, and crossflow regions and includes surface results for adiabatic effectiveness η and heat transfer coefficient h. Realistic geometries with length–to–diameter ratio of 4.0 and pitch–to–diameter ratio of 3.0 allowed for accurate capturing of the strong three–way coupling of flow in this multi–region flowfield. The cooling configurations implemented in this study exactly matched experimental work used for validation purposes and were represented by high quality computational grid meshes using a multi–block, unstructured grid topology. Blowing ratios of 1.25 and 1.88, and density ratio of 1.6 were used to simulate realistic operating conditions and to match the experiments used for validation. Predicted results for η and h show good agreement with experimental data.
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Newburry, Don, Pat Runnels, and Mike Owings. "Selective Catalytic Reduction (SCR) System Installation and Commissioning at the Chow II Power Plant in Chowchilla, California." In ASME 2003 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ices2003-0594.
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Lean burn, natural gas, reciprocating engines are becoming widely utilized for stationary industrial applications due to their high efficiency and low emissions. However, despite the low engine emissions, some locations still require exhaust after-treatment to meet the local emissions requirements. Due to the high oxygen content (greater than 4%) in the exhaust of lean burn engines, 3-Way (non-selective) catalysts are not suitable to reduce NOx. Selective catalytic reduction (SCR), which utilizes a consumable reductant to reduce NOx over a catalyst, is very effective at reducing NOx and is becoming an accepted technology for large, stationary engine applications. In the summer of 2001, Stewart & Stevenson installed 16 Deutz TGB632V16 natural gas fired engines for NEO Corporation at the Chow II power plant. MIRATECH SCR provided and commissioned 16 selective catalytic reduction systems for these engines using a 40% urea solution as the reductant. This paper describes the installed SCR systems and reports some of the emissions testing results and costs. With the SCR systems in place, the engines were successfully able to meet the permitted exhaust emissions requirements of 0.07 g/bhp-hr of NOx, 0.1 g/bhp-hr of CO, and 0.15 g/bhp-hr of VOC’s (volatile organic compounds) with less than 10 ppmvd of ammonia slip @ 15% O2. Additional measurements were made of formaldehyde and acrolein. Very low levels of these emissions were found after the SCR.
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Burger, Victor, Andy Yates, Thomas Mosbach, and Barani Gunasekaran. "Fuel Influence on Targeted Gas Turbine Combustion Properties: Part II — Detailed Results." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25105.
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The paper presents the results from a study that formed part of a bilateral project between DLR-VT and Sasol Technology Fuels Research aimed at investigating the potential influence of physical and chemical fuel properties on ignition and extinction limits within heterogeneous gas turbine combustion. The threshold of flame extinction and re-ignition behaviour of a range of alternative fuels was investigated in a representative aero-combustor sector to determine the relative influence of physical properties and chemical reaction timescales. A matrix of eight test fuels was selected for use during the study and included conventional crude-derived Jet A-1, synthetic paraffinic kerosene, linear paraffinic solvents, aromatic solvents and pure compounds. All test fuels were characterised through full specification analyses, distillation profiles and two-dimensional gas chromatography. The ignition and extinction behaviour of the test fuel matrix was evaluated under simulated altitude conditions at the Rolls-Royce Strategic Research Centre’s sub-atmospheric altitude ignition facility in Derby, UK. A twin sector segment of a Rich Quench Lean (RQL) combustor was employed with fuel supplied to a single burner. Combustor air inlet conditions were controlled to 41.4 kPa and 265 K. Fuel temperature was controlled to 288 K. In addition to the standard extinction and ignition detection systems, optical diagnostics were applied during the test programme. Simultaneous high-speed imaging of the OH* chemiluminescence, and broadband flame luminosity was employed to capture the main reaction zones, the global heat release and distribution of radiative soot particles respectively. Lean extinction points were determined using both a photodiode as well as from the OH* chemiluminescence data. The position of extinction and overall combustor ignition and extinction timescales were determined. The diagnostic methodology that was used to obtain the results reported in this paper is discussed in greater detail in a separate complementary paper. All eight fuels, including the fully synthetic Jet A-1 fuels that formed part of the test matrix, yielded performance that was comparable to that obtained with conventional crude-derived Jet A-1.
Reports on the topic "Lead (II) compounds"
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Fait, Aaron, Grant Cramer, and Avichai Perl. Towards improved grape nutrition and defense: The regulation of stilbene metabolism under drought. United States Department of Agriculture, May 2014. http://dx.doi.org/10.32747/2014.7594398.bard.
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The goals of the present research proposal were to elucidate the physiological and molecular basis of the regulation of stilbene metabolism in grape, against the background of (i) grape metabolic network behavior in response to drought and of (ii) varietal diversity. The specific objectives included the study of the physiology of the response of different grape cultivars to continuous WD; the characterization of the differences and commonalities of gene network topology associated with WD in berry skin across varieties; the study of the metabolic response of developing berries to continuous WD with specific attention to the stilbene compounds; the integration analysis of the omics data generated; the study of isolated drought-associated stress factors on the regulation of stilbene biosynthesis in plantaand in vitro. Background to the topic Grape quality has a complex relationship with water input. Regulated water deficit (WD) is known to improve wine grapes by reducing the vine growth (without affecting fruit yield) and boosting sugar content (Keller et al. 2008). On the other hand, irregular rainfall during the summer can lead to drought-associated damage of fruit developmental process and alter fruit metabolism (Downey et al., 2006; Tarara et al., 2008; Chalmers et al., 792). In areas undergoing desertification, WD is associated with high temperatures. This WD/high temperature synergism can limit the areas of grape cultivation and can damage yields and fruit quality. Grapes and wine are the major source of stilbenes in human nutrition, and multiple stilbene-derived compounds, including isomers, polymers and glycosylated forms, have also been characterized in grapes (Jeandet et al., 2002; Halls and Yu, 2008). Heterologous expression of stilbenesynthase (STS) in a variety of plants has led to an enhanced resistance to pathogens, but in others the association has not been proven (Kobayashi et al., 2000; Soleas et al., 1995). Tomato transgenic plants harboring a grape STS had increased levels of resveratrol, ascorbate, and glutathione at the expense of the anthocyanin pathways (Giovinazzo et al. 2005), further emphasizing the intermingled relation among secondary metabolic pathways. Stilbenes are are induced in green and fleshy parts of the berries by biotic and abiotic elicitors (Chong et al., 2009). As is the case for other classes of secondary metabolites, the biosynthesis of stilbenes is not very well understood, but it is known to be under tight spatial and temporal control, which limits the availability of these compounds from plant sources. Only very few studies have attempted to analyze the effects of different environmental components on stilbene accumulation (Jeandet et al., 1995; Martinez-Ortega et al., 2000). Targeted analyses have generally shown higher levels of resveratrol in the grape skin (induced), in seeded varieties, in varieties of wine grapes, and in dark-skinned varieties (Gatto et al., 2008; summarized by Bavaresco et al., 2009). Yet, the effect of the grape variety and the rootstock on stilbene metabolism has not yet been thoroughly investigated (Bavaresco et al., 2009). The study identified a link between vine hydraulic behavior and physiology of stress with the leaf metabolism, which the PIs believe can eventually lead to the modifications identified in the developing berries that interested the polyphenol metabolism and its regulation during development and under stress. Implications are discussed below.
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Fridman, Eyal, and Eran Pichersky. Tomato Natural Insecticides: Elucidation of the Complex Pathway of Methylketone Biosynthesis. United States Department of Agriculture, December 2009. http://dx.doi.org/10.32747/2009.7696543.bard.
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Plant species synthesize a multitude of specialized compounds 10 help ward off pests. and these in turn may well serve as an alternative to synthetic pesticides to reduce environmental damage and health risks to humans. The general goal of this research was to perform a genetic and biochemical dissection of the natural-insecticides methylketone pathway that is specific to the glandular trichomes of the wild species of tomato, Solanumhabrochaites f. glabratum (accession PI126449). Previous study conducted by us have demonstrated that these compounds are synthesized de novo as a derivate pathway of the fatty acid biosynthesis, and that a key enzyme. designated MethylketoneSynthase 1 (MKS 1). catalyzes conversion of the intermediate B-ketoacyl- ACPs to the corresponding Cn-1 methylketones. The approach taken in this proposed project was to use an interspecific F2 population. derived from the cross between the cultivated lV182 and the wild species PIl26449. for three objectives: (i) Analyze the association between allelic status of candidate genes from the fatty acid biosynthesis pathway with the methylketone content in the leaves (ii) Perform bulk segregant analysis of genetic markers along the tomato genome for identifying genomic regions that harbor QTLs for 2TD content (iii) Apply differential gene expression analysis using the isolated glands of bulk segregant for identifying new genes that are involved in the pathway. The genetic mapping in the interspecific F2 population included app. 60 genetic markers, including the candidate genes from the FAS pathway and SSR markers spread evenly across the genome. This initial; screening identified 5 loci associated with MK content including the candidate genes MKS1, ACC and MaCoA:ACP trans. Interesting observation in this genetic analysis was the connection between shape and content of the glands, i.e. the globularity of the four cells, typical to the wild species. was associated with increased MK in the segregating population. In the next step of the research transcriptomic analysis of trichomes from high- and 10w-MK plants was conducted. This analysis identified a new gene, Methy1ketone synthase 2 (MKS2), whose protein product share sequence similarity to the thioesterase super family of hot-dog enzymes. Genetic analysis in the segregating population confirmed its association with MK content, as well as its overexpression in E. coli that led to formation of MK in the media. There are several conclusions drawn from this research project: (i) the genetic control of MK accumulation in the trichomes is composed of biochemical components in the FAS pathway and its vicinity (MKS 1 and MKS2). as well as genetic factors that mediate the morphology of these specialized cells. (ii) the biochemical pathway is now realized different from what was hypothesized before with MKS2 working upstream to I\1KS 1 and serves as the interface between primary (fatty acids) and secondary (MK) metabolism. We are currently testing the possible physical interactions between these two proteins in vitro after the genetic analysis showed clear epistatic interactions. (iii) the regulation of the pathway that lead to specialized metabolism in the wild species is largely mediated by transcription and one of the achievements of this project is that we were able to isolate and verify the specificity of the MKS1 promoter to the trichomes which allows manipulation of the pathways in these cells (currently in progress). The scientific implications of this research project is the advancement in our knowledge of hitherto unknown biochemical pathway in plants and new leads for studying a new family in plants (hot dog thioesterase). The agricultural and biotechnological implication are : (i) generation of new genetic markers that could assist in importing this pathway to cultivated tomato hence enhancing its natural resistance to insecticides, (ii) the discovery of MKS2 adds a new gene for genetic engineering of plants for making new fatty acid derived compounds. This could be assisted with the use of the isolated and verified MKS1 promoter. The results of this research were summarized to a manuscript that was published in Plant Physiology (cover paper). to a chapter in a proceeding book. and one patent was submitted in the US.
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Ori, Naomi, and Mark Estelle. Role of GOBLET and Auxin in Controlling Organ Development and Patterning. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7697122.bard.
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The size and shape of plant leaves are extremely diverse within and among species, and are also sensitive to growth conditions. Compound leaves, such as those of tomato, maintain morphogenetic activity during early stages of their development, enabling them to elaborate lateral appendages such as leaflets. The aim of the research project was to understand the interaction between the plant hormone auxin, the putative auxin response inhibitor ENTIRE (E, SlIAA9) and the NAM/CUC transcription factor GOBLET (GOB) in compound-leaf development in tomato (Solanum lycopersicum). The specific aims of the project were: 1. Investigation of the role of GOB in compound-leaf development. 2. Characterization of E function in auxin signaling. 3. Characterization of the role of auxin in compound-leaf development. 4. Investigation of the genetic and molecular interaction between E and GOB. 5. Investigate the role of these factors in fruit development. There were no major changes in these objectives. GOB was shown to mark and promote the boundaries between the leaf and initiating leaflets. Its accurate distribution was found to be required for proper leaflet initiation and separation. E was found to interact with the TIR1 and AFB6 proteins in an auxin-dependant manner, indicating that these are functional auxin receptors that mediate E degradation in the presence of auxin. This was further supported by the stabilization of E by a mutation in domain II of the protein, which is thought to mediate its auxin-dependant degradation. Over expression of this stabilized form in tomato leaves and characterization of the e mutant phenotype and the E expression domain indicated that E acts between initiating leaflets to inhibit auxin response and lamina growth. Generation and analysis of tomato plants expressing the auxin response reporter DR5::VENUS, and analysis of the effect of auxin microapplication or overexpression of an auxin biosynthesis gene, indicated that auxin marks the sites of leaflet initiation and promotes lamina growth. Investigation of the molecular and genetic interaction between auxin, GOB and E revealed a complex network of mutual regulation that is utilized to precisely pattern the leaf margin in a manner that enables the combination of tight control and flexibility. E, auxin and GOB were shown to affect fruit development and fruit set, and in an extension of the project are currently utilized to identify new players that affect these processes. The research project yielded enhanced understanding of the mechanisms of compound leaf patterning and provided tools that will enable the manipulation of leaf shape and fruit set.
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Altstein, Miriam, and Ronald Nachman. Rationally designed insect neuropeptide agonists and antagonists: application for the characterization of the pyrokinin/Pban mechanisms of action in insects. United States Department of Agriculture, October 2006. http://dx.doi.org/10.32747/2006.7587235.bard.
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The general objective of this BARD project focused on rationally designed insect neuropeptide (NP) agonists and antagonists, their application for the characterization of the mechanisms of action of the pyrokinin/PBAN (PK-PBAN) family and the development of biostable, bioavailable versions that can provide the basis for development of novel, environmentally-friendly pest insect control agents. The specific objectives of the study, as originally proposed, were to: (i) Test stimulatory potencies of rationally designed backbone cyclic (BBC) peptides on pheromonotropic, melanotropic, myotropic and pupariation activities; (ii) Test the inhibitory potencies of the BBC compounds on the above activities evoked either by synthetic peptides (PBAN, LPK, myotropin and pheromonotropin) or by the natural endogenous mechanism; (iii) Determine the bioavailability of the most potent BBC compounds that will be found in (ii); (iv) Design, synthesize and examine novel PK/PBAN analogs with enhanced bioavailability and receptor binding; (v) Design and synthesize ‘magic bullet’ analogs and examine their ability to selectively kill cells expressing the PK/PBAN receptor. To achieve these goals the agonistic and antagonistic activities/properties of rationally designed linear and BBC neuropeptide (NP) were thoroughly studied and the information obtained was further used for the design and synthesis of improved compounds toward the design of an insecticide prototype. The study revealed important information on the structure activity relationship (SAR) of agonistic/antagonistic peptides, including definitive identification of the orientation of the Pro residue as trans for agonist activity in 4 PK/PBANbioassays (pheromonotropic, pupariation, melanotropic, & hindgut contractile) and a PK-related CAP₂b bioassay (diuretic); indications that led to the identification of a novel scaffold to develop biostbiostable, bioavailable peptidomimetic PK/PBANagonists/antagonists. The work led to the development of an arsenal of PK/PBAN antagonists with a variety of selectivity profiles; whether between different PKbioassays, or within the same bioassay between different natural elicitors. Examples include selective and non-selective BBC and novel amphiphilic PK pheromonotropic and melanotropic antagonists some of which are capable of penetrating the moth cuticle in efficacious quantities. One of the latter analog group demonstrated unprecedented versatility in its ability to antagonize a broad spectrum of pheromonotropic elicitors. A novel, transPro mimetic motif was proposed & used to develop a strong, selective PK agonist of the melanotropic bioassay in moths. The first antagonist (pure) of PK-related CAP₂b diuresis in flies was developed using a cisPro mimetic motif; an indication that while a transPro orientation is associated with receptor agonism, a cisPro orientation is linked with an antagonist interaction. A novel, biostablePK analog, incorporating β-amino acids at key peptidase-susceptible sites, exhibited in vivo pheromonotropic activity that by far exceeded that of PBAN when applied topically. Direct analysis of neural tissue by state-of-the-art MALDI-TOF/TOF mass spectrometry was used to identify specific PK/PK-related peptides native to eight arthropod pest species [house (M. domestica), stable (S. calcitrans), horn (H. irritans) & flesh (N. bullata) flies; Southern cattle fever tick (B. microplus), European tick (I. ricinus), yellow fever mosquito (A. aegypti), & Southern Green Stink Bug (N. viridula)]; including the unprecedented identification of mass-identical Leu/Ile residues and the first identification of NPs from a tick or the CNS of Hemiptera. Evidence was obtained for the selection of Neb-PK-2 as the primary pupariation factor of the flesh fly (N. bullata) among native PK/PK-related candidates. The peptidomic techniques were also used to map the location of PK/PK-related NP in the nervous system of the model fly D. melanogaster. Knowledge of specific PK sequences can aid in the future design of species specific (or non-specific) NP agonists/antagonists. In addition, the study led to the first cloning of a PK/PBAN receptor from insect larvae (S. littoralis), providing the basis for SAR analysis for the future design of 2ⁿᵈgeneration selective and/or nonselective agonists/antagonists. Development of a microplate ligand binding assay using the PK/PBAN pheromone gland receptor was also carried out. The assay will enable screening, including high throughput, of various libraries (chemical, molecular & natural product) for the discovery of receptor specific agonists/antagonists. In summary, the body of work achieves several key milestones and brings us significantly closer to the development of novel, environmentally friendly pest insect management agents based on insect PK/PBANNPs capable of disrupting critical NP-regulated functions.
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Gurevitz, Michael, William A. Catterall, and Dalia Gordon. face of interaction of anti-insect selective toxins with receptor site-3 on voltage-gated sodium channels as a platform for design of novel selective insecticides. United States Department of Agriculture, December 2013. http://dx.doi.org/10.32747/2013.7699857.bard.
Full textAbstract:
Voltage-gated sodium channels (Navs) play a pivotal role in excitability and are a prime target of insecticides like pyrethroids. Yet, these insecticides are non-specific due to conservation of Navs in animals, raising risks to the environment and humans. Moreover, insecticide overuse leads to resistance buildup among insect pests, which increases misuse and risks. This sad reality demands novel, more selective, insect killers whose alternative use would avoid or reduce this pressure. As highly selective insect toxins exist in venomous animals, why not exploit this gift of nature and harness them in insect pest control? Many of these peptide toxins target Navs, and since their direct use via transformed crop plants or mediator microorganisms is problematic in public opinion, we focus on the elucidation of their receptor binding sites with the incentive of raising knowledge for design of toxin peptide mimetics. This approach is preferred nowadays by agro-industries in terms of future production expenses and public concern. However, characterization of a non-continuous epitope, that is the channel receptor binding site for such toxins, requires a suitable experimental system. We have established such a system within more than a decade and reached the stage where we employ a number of different insect-selective toxins for the identification of their receptor sites on Navs. Among these toxins we wish to focus on those that bind at receptor site-3 and inhibit Nav inactivation because: (1) We established efficient experimental systems for production and manipulation of site-3 toxins from scorpions and sea anemones. These peptides vary in size and structure but compete for site-3 on insect Navs. Moreover, these toxins exhibit synergism with pyrethroids and with other channel ligands; (2) We determined their bioactive surfaces towards insect and mammalian receptors (see list of publications); (3) We found that despite the similar mode of action on channel inactivation, the preference of the toxins for insect and mammalian channel subtypes varies greatly, which can direct us to structural features in the basis of selectivity; (4) We have identified by channel loop swapping and point mutagenesis extracellular segments of the Navinvolved with receptor site-3. On this basis and using channel scanning mutagenesis, neurotoxin binding, electrophysiological analyses, and structural data we offer: (i) To identify the residues that form receptor site-3 at insect and mammalian Navs; (ii) To identify by comparative analysis differences at site-3 that dictate selectivity toward various Navs; (iii) To exploit the known toxin structures and bioactive surfaces for modeling their docking at the insect and mammalian channel receptors. The results of this study will enable rational design of novel anti-insect peptide mimetics with minimized risks to human health and to the environment. We anticipate that the release of receptor site-3 molecular details would initiate a worldwide effort to design peptide mimetics for that site. This will establish new strategies in insect pest control using alternative insecticides and the combined use of compounds that interact allosterically leading to increased efficiency and reduced risks to humans or resistance buildup among insect pests.
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Morrison, Mark, Joshuah Miron, Edward A. Bayer, and Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, March 2004. http://dx.doi.org/10.32747/2004.7586475.bard.
Full textAbstract:
Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).
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Morin, Shai, Gregory Walker, Linda Walling, and Asaph Aharoni. Identifying Arabidopsis thaliana Defense Genes to Phloem-feeding Insects. United States Department of Agriculture, February 2013. http://dx.doi.org/10.32747/2013.7699836.bard.
Full textAbstract:
The whitefly (Bemisia tabaci) is a serious agricultural pest that afflicts a wide variety of ornamental and vegetable crop species. To enable survival on a great diversity of host plants, whiteflies must have the ability to avoid or detoxify numerous different plant defensive chemicals. Such toxins include a group of insect-deterrent molecules called glucosinolates (GSs), which also provide the pungent taste of Brassica vegetables such as radish and cabbage. In our BARD grant, we used the whitefly B. tabaci and Arabidopsis (a Brassica plant model) defense mutants and transgenic lines, to gain comprehensive understanding both on plant defense pathways against whiteflies and whitefly defense strategies against plants. Our major focus was on GSs. We produced transgenic Arabidopsis plants accumulating high levels of GSs. At the first step, we examined how exposure to high levels of GSs affects decision making and performance of whiteflies when provided plants with normal levels or high levels of GSs. Our major conclusions can be divided into three: (I) exposure to plants accumulating high levels of GSs, negatively affected the performance of both whitefly adult females and immature; (II) whitefly adult females are likely to be capable of sensing different levels of GSs in their host plants and are able to choose, for oviposition, the host plant on which their offspring survive and develop better (preference-performance relationship); (III) the dual presence of plants with normal levels and high levels of GSs, confused whitefly adult females, and led to difficulties in making a choice between the different host plants. These findings have an applicative perspective. Whiteflies are known as a serious pest of Brassica cropping systems. If the differences found here on adjacent small plants translate to field situations, intercropping with closely-related Brassica cultivars could negatively influence whitefly population build-up. At the second step, we characterized the defensive mechanisms whiteflies use to detoxify GSs and other plant toxins. We identified five detoxification genes, which can be considered as putative "key" general induced detoxifiers because their expression-levels responded to several unrelated plant toxic compounds. This knowledge is currently used (using new funding) to develop a new technology that will allow the production of pestresistant crops capable of protecting themselves from whiteflies by silencing insect detoxification genes without which successful host utilization can not occur. Finally, we made an effort to identify defense genes that deter whitefly performance, by infesting with whiteflies, wild-type and defense mutated Arabidopsis plants. The infested plants were used to construct deep-sequencing expression libraries. The 30- 50 million sequence reads per library, provide an unbiased and quantitative assessment of gene expression and contain sequences from both Arabidopsis and whiteflies. Therefore, the libraries give us sequence data that can be mined for both the plant and insect gene expression responses. An intensive analysis of these datasets is underway. We also conducted electrical penetration graph (EPG) recordings of whiteflies feeding on Arabidopsis wild-type and defense mutant plants in order to determine the time-point and feeding behavior in which plant-defense genes are expressed. We are in the process of analyzing the recordings and calculating 125 feeding behavior parameters for each whitefly. From the analyses conducted so far we conclude that the Arabidopsis defense mutants do not affect adult feeding behavior in the same manner that they affect immatures development. Analysis of the immatures feeding behavior is not yet completed, but if it shows the same disconnect between feeding behavior data and developmental rate data, we would conclude that the differences in the defense mutants are due to a qualitative effect based on the chemical constituency of the phloem sap.