subject:( Pyrrolnitrin)

Queens University

1. Hu, Di. Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway .

Degree: Chemistry, 2010, Queens University

URL: http://hdl.handle.net/1974/5426

► Chapter 1 Hydrocarbon autoxidation, a free radical chain reaction, is believed to play a key role in the onset and developments of most degenerative diseases… (more)

▼ Chapter 1 Hydrocarbon autoxidation, a free radical chain reaction, is believed to play a key role in the onset and developments of most degenerative diseases and disorders. The two propagating steps: 1) H-atom abstraction from the hydrocarbon by a hydrocarbon-derived peroxyl radical, and 2) addition of oxygen to the resultant alkyl radical to form a new peroxyl, play a role in determining the rate of hydrocarbon autoxidation, as well as the regio- and stereochemistry of the product hydroperoxides. In the current study, we carried out a set of calculations to provide a detailed framework for understanding the mechanism of the first two steps of autoxidation. Chapter 2 Radical-trapping chain-breaking antioxidants inhibit hydrocarbon autoxidation. Phenols are the prototypical radical-trapping antioxidants and are employed in nature, as well as in industry, to inhibit the autoxidation of hydrocarbons. The mechanism of inhibiting radical chain propagation has recently been suggested to be a PCET on the basis of theoretical calculations. It has been demonstrated that the antioxidant activitiy of phenols is increased in the presence of either protic acids or alcohols, but the basis of this acceleration is not well understood. In the current study, we used computational methods to investigate the effects of acids and alcohols on the PCET pathway for the reaction of phenol with a peroxyl radical. Chapter 3 The antibiotic pyrrolnitrin [3-chloro-4-(2’-nitro-3’-chlorophenyl) pyrrole] (PRN) is biosynthesized from L-tryptophan in four steps, catalyzed by the enzymes PrnA, B, C and D encoded by the prn operon. Two of the four gene products, PrnA and PrnC, are flavin-dependent halogenases, a recently discovered and highly interesting class of enzymatic halogenation catalysts. Their activities have never been unequivocally demonstrated by reconstitution of the activity from a recombinant protein. Herein, we report the results of our efforts to clone the genes encoding PrnA and PrnC, and overexpress, isolate and purify the proteins from E. coli. We were able to successfully reconsistute halogenation activity of both and have obtained the first kinetic data for PrnC, which shows kinetics similar to other flavin-dependent halogenases, along with substrate inhibition.

Subjects/Keywords: Lipid Autoxidation; Propagation; Beta-Fragmentation; Computational; PCET; Oxygen Dependent Halogenase; Pyrrolnitrin; PrnC; Kinetic; E,coli

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hu, D. (2010). Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway . (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/5426

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hu, Di. “Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway .” 2010. Thesis, Queens University. Accessed December 06, 2019. http://hdl.handle.net/1974/5426.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hu, Di. “Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway .” 2010. Web. 06 Dec 2019.

Vancouver:

Hu D. Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway . [Internet] [Thesis]. Queens University; 2010. [cited 2019 Dec 06]. Available from: http://hdl.handle.net/1974/5426.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hu D. Computational Studies of Lipid Autoxidation and Solvent-Mediated Antioxidant Activity and a Kinetic Study of a Halogenase in the Pyrrolnitrin Biosynthetic Pathway . [Thesis]. Queens University; 2010. Available from: http://hdl.handle.net/1974/5426

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Wong, Lina Chuan. Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real.

Degree: Mestrado, Biologia na Agricultura e no Ambiente, 2011, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/64/64133/tde-08022012-092220/ ;

► A Terra Preta Antropogênica (TPA) é considerada um dos solos mais férteis do mundo e recebe essa denominação por ser originada da ação antrópica, provavelmente… (more)

▼ A Terra Preta Antropogênica (TPA) é considerada um dos solos mais férteis do mundo e recebe essa denominação por ser originada da ação antrópica, provavelmente de populações pré-colombianas que viveram nestes sítios arqueológicos. O crescente aumento por agricultura sustentável torna a utilização de bactérias produtoras de antibióticos uma alternativa de controle para doenças de plantas. Pirrolnitrina (PRN) é um antibiótico que tem ampla atividade antimicrobiana produzida por várias estirpes de Burkholderia e Pseudomonas que foram isoladas de diferentes solos. Entretanto, não se tem conhecimento de isolados bacterianos de TPA que produzem PRN, assim com, sobre a ecologia e freqüência do gene para este antibiótico. A PRN é codificada por um operon composto por 4 genes sendo o gene prnD responsável por catalisar a oxidação que forma a pirrolnitrina. Neste trabalho, foi estudado o gene prnD através de métodos dependente e independente de cultivo. Foram utilizados isolados bacterianos para detectar o gene prnD através de PCR convencional e a identificação feita pelo seqüenciamento. As bactérias com amplificação positiva tiveram suas sequências do gene analisadas no programa MOTHUR o qual reuniu as em 10 grupos. Um representante de cada grupo foi empregado no teste de antagonismo contra o fitopatógeno Fusarium oxysporum. Amostras de solo de TPA e seus solos adjacentes foram coletados de dois sítios: Caldeirão Capoeira (floresta secundária por mais de 20 anos) e Cultivado (cultivado com mandioca por pelo menos 30 anos). Os DNAs totais das amostras de solo extraído foram usados como molde nas reações de PCR quantitativo em tempo real para verificar a abundância do gene prnD nas amostras de solo. Em amostras de solo também foi quantificado o gene 16S rRNA. No estudo dependente de cultivo, do total de 219 isolados (175 Burkholderia e 44 Pseudomonas), 60 isolados do gênero Burkholderia e 3 de Pseudomonas exibiram amplificação positiva. A análise filogenética do gene prnD mostrou que a maioria das seqüências obtidas deste estudo não agruparam com as seqüências do banco de dados do GenBank indicando que há diversidade do gene prnD nos isolados de solos amazônicos e que podem ser distintos dos descritos anteriormente. O teste de antagonismo demonstrou que isolados com potencial genético para produção de pirrolnitrina também são bioativos contra Fusarium oxysporum, apresentando forte atividade antimicrobiana. No estudo independente de cultivo, no sítio Caldeirão Cultivado, solo de TPA apresentou maior número de cópias do gene prnD e do gene 16S rRNA em relação ao solo ADJ. No sítio Caldeirão Capoeira, o solo adjacente apresentou maior quantidade do gene prnD (1,74x105 cópias/g solo) que o solo de TPA (2,48x104 cópias/ g de solo), no entanto, na TPA as bactérias totais foram mais abundante. Estes resultados evidenciam que a metodologia de PCR quantitativo em tempo real desenvolvida foi altamente sensível e específica permitindo a detecção de diferenças sensíveis e significativas entre os solos na quantificação do gene prnD. A… Advisors/Committee Members: Monteiro, Regina Teresa Rosim.

Subjects/Keywords: Anthropogenic Dark Earth; Antibiotic-producing bacteria; Antimicrobial activity; Atividade antimicrobiana; Bactérias produtoras de antibiótico; PCR em tempo real; Pirrolnitrina; Pyrrolnitrin; Real-Time PCR; Terra Preta Antropogênica

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wong, L. C. (2011). Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/64/64133/tde-08022012-092220/ ;

Chicago Manual of Style (16^th Edition):

Wong, Lina Chuan. “Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real.” 2011. Masters Thesis, University of São Paulo. Accessed December 06, 2019. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-08022012-092220/ ;.

MLA Handbook (7^th Edition):

Wong, Lina Chuan. “Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real.” 2011. Web. 06 Dec 2019.

Vancouver:

Wong LC. Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real. [Internet] [Masters thesis]. University of São Paulo; 2011. [cited 2019 Dec 06]. Available from: http://www.teses.usp.br/teses/disponiveis/64/64133/tde-08022012-092220/ ;.

Council of Science Editors:

Wong LC. Identificação e quantificação do gene pirrolnitrina (prnD) em Terra Preta Antropogênica da Amazônia por PCR em tempo real. [Masters Thesis]. University of São Paulo; 2011. Available from: http://www.teses.usp.br/teses/disponiveis/64/64133/tde-08022012-092220/ ;

3. Ajouz, Sakhr. Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides.

Degree: Docteur es, Sciences agronomiques, 2009, Avignon

URL: http://www.theses.fr/2009AVIG0622

► La pourriture grise, causée par le champignon Botrytis cinerea, est l'une des principales maladies aériennes fongiques sur diverses cultures d’importance agronomique. La diversité génétique de… (more)

▼ La pourriture grise, causée par le champignon Botrytis cinerea, est l'une des principales maladies aériennes fongiques sur diverses cultures d’importance agronomique. La diversité génétique de B. cinerea est très forte et la capacité rapide d’adaptation de ce champignon à une pression sélective est également avérée. Ce champignon est ainsi capable de développer des résistances à une grande variété de composés fongicides de synthèse ou d'origine naturelle. Des méthodes alternatives de lutte ont de ce fait été développées ces dernières années : divers agents de lutte biologique (ALB) présentant différents modes d’actions ont été identifiés et pour certains d’entre eux commercialisés pour contrôler B. cinerea. Cependant la durabilité de la lutte biologique est un domaine encore très peu étudié. La perte d'efficacité d'un ALB pourrait résulter de la préexistence d’isolats moins sensibles de pathogènes dans les populations naturelles et/ou de la capacité de l’agent pathogène à produire, sous une pression de sélection continue exercée par l’ALB, des mutants ayant une sensibilité réduite. L'objectif global de la présente étude est d'évaluer le risque potentiel de perte d'efficacité de la lutte biologique vis-à-vis de B. cinerea. Dans cette étude, les efforts ont été concentrés sur la pyrrolnitrine, un antibiotique produit par divers ALBs, dont certains sont efficaces contre B. cinerea. Les objectifs spécifiques de l'étude étaient (i) d’évaluer la diversité de la sensibilité à la pyrrolnitrine au sein de la population naturelle de B. cinerea, (ii) d'estimer le risque de perte d'efficacité des ALBs produisant la pyrrolnitrine due à la pression de sélection exercée par la pyrrolnitrine et (iii) d'étudier le mécanisme de résistance à la pyrrolnitrine chez B. cinerea. Parmi 204 isolats de B. cinerea, une gamme importante de sensibilité à la pyrrolnitrine a été observée, avec un facteur de résistance de 8,4 entre l’isolat le plus sensible et l'isolat le moins sensible. La production de 20 générations successives pour 4 isolats de B. cinerea, sur des doses croissantes de pyrrolnitrine, a abouti au développement de mutants avec des niveaux élevés de résistance à l'antibiotique, et à une réduction in vitro de la sensibilité à la bactérie productrice de pyrrolnitrine Pseudomonas chlororaphis PhZ24. La comparaison entre les mutants résistants à la pyrrolnitrine et leurs parents sensibles pour la croissance mycélienne, la sporulation et l'agressivité sur plantes a révélé que la résistance à la pyrrolnitrine est associée à un fort coût adaptatif. Des observations cytohistologiques sur tomates ont confirmé que l’isolat sensible à la pyrrolnitrine attaque le pétiole rapidement et envahit la tige, alors que le mutant résistant à la pyrrolnitrine ne s'étend pas au-delà du pétiole. De plus, ce dernier mutant forme un mycélium anormal et des cellules ressemblant à des chlamydospores. Les résultats ont d'autre part révélé que les mutants de B. cinerea résistants à la pyrrolnitrine sont résistants au fongicide iprodione, suggérant ainsi qu'une… Advisors/Committee Members: El Maataoui, Mohamed (thesis director), Bardin, Marc (thesis director).

Subjects/Keywords: Botrytis cinerea; Lutte biologique; Durabilité; Pyrrolnitrine; Pseudomonas chlororaphis PhZ24; Diversité; Fongicides; Histidine kinase; Mutation; Cytohistologie; Evolution expérimentale; Microsatellite; Botrytis cinerea; Biological control; Durability; Pyrrolnitrin; Pseudomonas chlororaphis PhZ24; Diversity; Fungicides; Histidine kinase; Mutation; Cytohistology; Experimental evolution; Microsatellite

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ajouz, S. (2009). Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides. (Doctoral Dissertation). Avignon. Retrieved from http://www.theses.fr/2009AVIG0622

Chicago Manual of Style (16^th Edition):

Ajouz, Sakhr. “Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides.” 2009. Doctoral Dissertation, Avignon. Accessed December 06, 2019. http://www.theses.fr/2009AVIG0622.

MLA Handbook (7^th Edition):

Ajouz, Sakhr. “Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides.” 2009. Web. 06 Dec 2019.

Vancouver:

Ajouz S. Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides. [Internet] [Doctoral dissertation]. Avignon; 2009. [cited 2019 Dec 06]. Available from: http://www.theses.fr/2009AVIG0622.

Council of Science Editors:

Ajouz S. Estimation du potentiel de résistance de Botrytis cinerea à des biofongicides : Estimate of potential resistance of Botrytis cinerea to biofungicides. [Doctoral Dissertation]. Avignon; 2009. Available from: http://www.theses.fr/2009AVIG0622

Queens University

4. Morrison, Matthew. A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles .

Degree: Chemistry, 2009, Queens University

URL: http://hdl.handle.net/1974/5265

► This thesis details a straightforward synthetic route to the antifungal compound pyrrolnitrin 1.2, along with several analogous halogenated phenylpyrroles. The proposed synthetic protocol involved the… (more)

Subjects/Keywords: pyrrolnitrin; halogenases; Schmidt reaction; Directed ortho Metalation; 2; 6-dihaloanilines; 2; 6-dihalonitrobenzenes; 3-substituted pyrroles; cross-coupling with pyrroles

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Morrison, M. (2009). A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles . (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/5265

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Morrison, Matthew. “A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles .” 2009. Thesis, Queens University. Accessed December 06, 2019. http://hdl.handle.net/1974/5265.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Morrison, Matthew. “A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles .” 2009. Web. 06 Dec 2019.

Vancouver:

Morrison M. A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles . [Internet] [Thesis]. Queens University; 2009. [cited 2019 Dec 06]. Available from: http://hdl.handle.net/1974/5265.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Morrison M. A Convenient Synthesis of Pyrrolnitrin and Related Halogenated Phenylpyrroles . [Thesis]. Queens University; 2009. Available from: http://hdl.handle.net/1974/5265

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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