Dissertations / Theses: 'Pseudoalteromonas'

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Sousa, Thiciana da Silva. "Micro-organismos marinhos produtores de metabólitos secundários biologicamente ativos." reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/14106.

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SOUSA, T. S.; PESSOA, O. D. L. Micro-organismos marinhos produtores de metabólitos secundários biologicamente ativos. 2013. 228 f. Tese (Doutorado em Química Orgânica) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2013.
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This work describe the chemical and biological investigation of the extracts from the marine bacterias Pseudoalteromonas sp., Micromonospora sp., Streptomyces sp. and Kocuria sp., aiming the isolation and structural elucidation of new bioactive constituents. The chemical investigation carried out with the bacteria Pseudoalteromonas sp. lead to the isolation a red pigment identified as prodigiosin and two bile acids derivatives known as deoxycholic acid and cholic acid. The prodigiosin was evaluated against four tumor cell lines showing IC50 values similar to the positive control doxorubicin. The chemical study of Micromonospora sp. Resulted in the isolation of four new anthracyclinones designed as 4,6,11-trihydroxy-9-propryltetracene-5,12-dione; 4-methoxy-9-propyltetracene-6,11-dione; 7,8,9,10 - tetrahydro-9-hydroxy-4-methoxy-9-propiltetra-cene-6,11-dione and 10β-Carbomethoxy-7,8,9,10-tetrahydro-4,6,7α,9α,11-pentahydroxy-9-propyltetracene-5,12-dione . The cytotoxic potential of these compounds were evaluated against HCT-8cell line, two of which showed moderate cytotoxicity with IC50 values of 12.74 and 6.18 M, respectively. From Streptomyces sp. strain was isolated a ditiolpyrrolidin, established as 5-oxo-6-(N-methylformamide) -4,5 - dihydro-1,2-dithiol [4,3-b] pyrrole. This secondary metabolite was tested against six tumor cell lines, shown IC50 values of 1.66, 1.05 and 1.52 mM for the metastatic prostate lines, ovarium carcinoma and glioblastoma, respectively. The study of Kocuria sp. lead to the isolation of a new peptide, which was designed as kocurin. This compound was subjected to the tested its antimicrobial assays against several pathogens bacteria and fungal including Staphylococcus aureus strains methicillin resistant (MRSA) and Staphylococcus aureus strains tiazomicin resistant. Kocurin was strongly active against MRSA MB5393 exhibiting a MIC of 0,25µg/mL, moreover showed antibacterial activity against Bacillus subtilis and Enterococcus faecium. The structures of all isolated compounds in this work were stabilized employing spectroscopic methods such as 1H and 13C NMR (1D and 2D), mass spectrometry and infrared.
Este trabalho descreve o estudo químico e biológico dos extratos das bactérias marinhas Pseudoalteromonas sp., Micromonospora sp., Streptomyces sp. e Kocuria sp., visando o isolamento e a elucidação estrutural de novos constituintes bioativos. A investigação química realizada com a bactéria Pseudoalteromonas sp. resultou no isolamento de um pigmento vermelho identificado como prodigiosina e de dois ácidos biliares conhecidos como ácido desoxicólico e ácido cólico. A prodigiosina foi testada frente a quatro linhagens de células tumorais e apresentou valores de IC50 semelhantes ao padrão positivo. O estudo químico de Micromonospora sp. resultou no isolamento de quatro novas antraciclinonas: 4,6,11-triidroxi-9-propriltetraceno-5,12-diona; 4-metoxi-9-propiltetraceno-6,11-diona; 7,8,9,10-tetraidro-9-hidroxi-4-metoxi-9-propiltetra-ceno-6,11-diona e 10β-metoxicarbonil-7,8,9,10-tetraidro-4,6,7α,9α,11–pentaidroxi–9–propil-tetraceno-5,12-diona. Esses compostos foram avaliados quanto a sua atividade anti-tumoral frente a linhagem celular HCT-8, dois dos quais mostraram citotoxidade moderada com valores de IC50 de 12,74 e 6,18 M. O estudo da bactéria Streptomyces sp. possibilitou o isolamento de uma ditiolpirrolidina cuja estrutura foi estabelecida como 5-oxo-6-(N-metilformamida)-4,5- diidro-1,2-ditiol[4,3-b]pirrol. Esse metabólito teve sua atividade citotóxica testada frente a seis linhagens celulares tumorais, mostrando forte atividade com IC50 de 1,66, 1,05 e 1,52 µM para as linhagens de próstata metastática, carcinoma de ovário e glioblastoma, respectivamente. O estudo de Kocuria sp. resultou no isolamento de um novo peptídeo denominado como kocurina. Esse composto teve sua atividade antimicrobiana testada frente a várias bactérias e fungos patogênicos, incluindo cepas de Staphylococcus aureus resistentes a meticilina (MRSA) e cepas de Staphylococcus aureus resistentes a tiazomicina. Kocurina inibiu fortemente o crescimento de MRSA MB5393 com valores de CIM de 0,25µg/mL, além de exibir atividade antibacteriana contra as bactérias Bacillus subtilis e Enterococcus faecium. As estruturas de todos os compostos isolados neste trabalho foram determinadas empregando métodos espectroscópicos tais como RMN 1H e 13C (1D e 2D), espectrometria de massas e infravermelho.

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Evans, Flavia F. Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "Analysis of the secretome and type II secretion in pseudoalteromonas tunicata." Awarded by:University of New South Wales. Biotechnology & Biomolecular Sciences, 2007. http://handle.unsw.edu.au/1959.4/40449.

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The eukaryote-associated Pseudoalteromonas tunicata produces two pigments and several other bioactive compounds that are able to inhibit a range of marine organisms including bacteria, protozoa, fungi, algal spores and invertebrate larvae. Early studies suggested that the production of bioactive compounds is correlated with pigmentation in P. tunicata. In one of these studies, a transposon mutagenesis library identified a white mutant, wmpD-, which had been disrupted in a gene encoding a component of the type 11 secretion (T2S) machinery. The T2S system is involved in the transport of different extracellular enzymes in many bacteria. In some cases, the T2S pathway also exports proteins that remain attached to the cells. This thesis aimed to investigate the role of the T2S pathway in the production of the pigments and bioactive compounds in P. tunicata. In order to gain insight into this relationship, two proteomics approaches (2D-PAGE and iTRAQ) were applied to investigate the profile of the secreted proteins (or secretome) in P. tunicata wild-type and the white mutant wmpD-. Proteomic analysis using 2D-PAGE revealed that 23 proteins were differentially expressed between P. tunicata Wt and the mutant wmpD-. The identities of some of these proteins could be correlated with the function of the T2S system in P. tunicata. The role of one of the proteins identified using 2D-PAGE was further investigated through the construction of a gene knockout mutant (hiik mutant). The supernatant activity of the hiik mutant was compared to that of P. tunicata Wt, and it was found that the HiiA protease is required to block the activity of antimicrobial peptides, such as cecropins, produced by eukaryotic hosts in the environment. The second proteomics approach (iTRAQ) used in this thesis, enabled the relative quantitation of a number of proteins in the supernatant of P. tunicata Wt and the white mutant wmpD-. Some proteins with no function to date (hypothetical) were absent in the extracellular fraction of the wmpD- mutant, indicating they may be transported to the extracellular environment via the T2S pathway in P. tunicata. The comparative analysis of the secretome also revealed that TonS-related proteins, involved in iron acquisition, were up-regulated in the wmpD- mutant, possibly to compensate for the lack of TonS-dependant receptors in the outer membrane. Assays for iron binding activity showed that P. tunicata Wt seems to release iron binding compounds (or siderophores) constitutively into the supernatant, in contrast to the white mutant wmpD-, which responds to iron limitation by increasing the production of siderophores. Further outer membrane fractionation studies, indicated that the P. tunicata T2S system is likely to be involved in the transport of TonB-dependant receptors to the outer membrane. The overall results discussed in this thesis indicate that the T2S system has an essential role in the general physiology of P. tunicata, as for iron metabolism, as well as in the in the relationship between this bacterium and eukaryotic hosts in the environment.

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Sijerčić, Ada. "Kinetics of siderophore production by a marine bacterium, Pseudoalteromonas haloplanktis." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116077.

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Siderophores are secreted by marine bacteria to increase Fe uptake when Fe is limiting but are not produced when sufficient Fe is present to saturate growth. These results are well established in laboratory batch cultures of a number of isolates obtained from the open sea. Little is known, however, regarding the kinetics of siderophore secretion by heterotrophic bacteria in response to transients in Fe deprivation and resupply. We examined growth, hydroxamate siderophore concentration, and electron transport chain activity (a biochemical measure of Fe nutritional state) of Pseudoalteromonas haloplanktis, a representative gamma-proteobacterium from the Fe deficient region of the subarctic Pacific Ocean. Hydroxamate concentration was roughly 5-fold higher in batch cultures grown in low than in high Fe medium. Iron injection to the low Fe cultures repressed hydroxamic acid production and increased growth and ETC activity. Steady-state hydroxamate concentration in the chemostat increased 5-fold as Fe-limited growth rate declined from 9.8 to 2.8 d -1. This increase compounded to a 2.8-fold change in hydroxamates cell-1 reflecting the greater costs of growth at low Fe. Three types of Fe perturbation were made to Fe-limited chemostat cultures: 1) A switch perturbation that decreased the dilution rate of the chemostat-by ∼3-fold caused a transient increase in cell density that subsequently declined to a new steady state level. Hydroxamate concentration increased linearly over the same time. 2) A transient addition of dissolved Fe increased the total hydroxamate concentration in the chemostat within 1-3 hours which was followed by a decrease and then subsequent increase as the cells re-entered Fe-limitation. Dilution rate affected the response. Normalized to bacteria density, hydroxamate concentration remained constant for the first 2 hours after the Fe addition and then declined and returned to pre-infusion levels. Thus, Fe addition stimulated siderophore production by increasing the density of bacteria, which continued to secrete hydroxamates at a Fe-limited rate. 3) A continuous addition of low levels of dissolved Fe increased bacteria density and siderophore concentration. The net secretion rate of siderophores was proportional to the increase in Fe supply rate to the chemostat. At high Fe concentration, hydroxamate concentration declined to undetectable levels as the bacteria became Fe-sufficient and C-limited. Siderophore secretion by Fe-limited P. haloplanktis was repressed after 2 hours (corresponding roughly to 1-2 cell generations) following Fe re-supply.

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EVANGELISTA, Giovanna. "Caratterizzazione molecolare e funzionale della Polinucleotide fosforilasi dall'eubatterio antartico Pseudoalteromonas Haloplanktis." Doctoral thesis, Università degli studi del Molise, 2010. http://hdl.handle.net/11695/66405.

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L’enzima polinucleotide fosforilasi (PNPasi, E.C. 2.7.7.8) è coinvolto nel metabolismo dei nucleotidi, sia negli eucarioti che nei procarioti. L’enzima catalizza la degradazione fosforolitica dell’RNA, rilasciando nucleosidi 5’-difosfato dall’estremità 3’ del substrato, e la reazione inversa di polimerizzazione. In questo lavoro è descritta la purificazione e la caratterizzazione biochimica della PNPasi isolata dall’eubatterio psicrofilo di origine Antartica Pseudoalteromonas haloplanktis (Ph, temperatura ottimale di crescita 4-20°C) identificata sulla base della sua capacità di catalizzare la seguente reazione reversibile: RNA(n) + Pi ↔ RNA(n-1) + ppN L’enzima ha mostrato una struttura omotrimerica con un Mr pari a 255000, come valutato da analisi della massa molecolare in condizioni native e denaturanti. Utilizzando software bioinformatici dedicati sono state ottenute, a partire dalla sequenza amminoacidica, predizioni della struttura secondaria e terziaria del monomero. Inoltre, sono stati condotti studi sulla composizione amminoacidica che hanno permesso di evidenziare che la PhPNPasi mostra i tipici adattamenti delle proteine psicrofile. I parametri cinetici sono stati determinati a 15°C, utilizzando poli(A) come primer e GDP marcato come substrato. E’ stato valutato l’effetto sull’attività enzimatica di concentrazioni crescenti di GDP, consentendo di calcolare i parametri cinetici. L’attività della PhPNPasi è risultata essere stimolata dalla presenza di alcuni cationi monovalenti nella miscela di reazione, caratteristica già evidenziata per un altri enzimi isolati da P. haloplanktis. Tra essi il CsCl ad una concentrazione 0,9 M è risultato il più efficace, aumentando l’attività dell’enzima di circa 7 volte. L’attività enzimatica della PhPNPasi aumenta con l’incremento della temperatura, raggiungendo un valore massimo a 40°C; oltre questa temperatura si osserva un decremento della velocità di reazione, probabilmente dovuto alla sua inattivazione termica. Nell’intervallo 0-40°C è stato calcolato un valore di energia di attivazione (Ea) pari a 87 kJ/mol. La PhPNPasi è un enzima piuttosto sensibile al trattamento termico, infatti l’energia di attivazione della reazione di inattivazione termica nell’intervallo 30-70°C è risultata pari a 96,7 kJ/mol, valore significativamente più basso di quello osservato per altre proteine isolate da fonti mesofile o termofile. La termostabilità di questo enzima è stata valutata anche con analisi di tipo spettroscopico. Le curve di UV melting hanno mostrato una temperatura di semidenaturazione di 46°C, valore significativamente più alto di quello a cui si registra la massima attività catalitica. I risultati indicano che il centro catalico della PhPNPasi è molto meno stabile del resto della struttura della proteina.
Polynucleotide phosphorylase (PNPase) is involved in the nucleotide metabolism pathway of both eukaryotes and prokaryotes. The enzyme catalyzes the phosphorolytic degradation of RNA, releasing nucleoside 5’-diphosphates from the 3’ end of the substrate, and the reverse reaction of nucleoside 5’-diphosphate polymerization. In this work it’s described the procedure of isolation and the characterization of PNPase from the psychrophilic eubacterium Pseudoalteromonas haloplanktis (Ph, optimal growth condition 4-20°C), identified for its ability to catalyse the following reversible reaction: RNA(n) + Pi ↔ RNA(n-1) + ppN PhPNPase showed a homotrimeric structure of 255 kDa, as evaluated by molecular mass analysis under native and denatured conditions. Using bioinformatic software, starting from the amino acid sequence, a prediction of the secondary and tertiary monomer structure have been obtained. Besides, studies on the amino acid composition have been carried out, thus evidencing that PhPNPase shows the typical adaptation of proteins isolated from psychrophilic organisms. The kinetic parameters have been determined at 15°C, using poly(A) as a primer and [3H]GDP as substrate. The effect of increasing concentration of [3H]GDP on the activity has been evaluated, thus allowing the determination of the kinetic parameters of the polymerization reaction. The activity of PhPNPase is stimulated by selected monovalent cations added in the reaction mixture, a feature already observed for other enzymes isolated from P. haloplanktis. Among the cations tested, CsCl, added to 0.9 M final concentration, has resulted the most effective, enhancing PhPNPase activity of about 7-fold. The effect of temperature on the activity and stability of PhPNPase has also been tested. In particular, the activity of PhPNPase increases with increasing temperature, reaching a maximum at 40°C; beyond this temperature a straight decay of the activity has been observed, due to thermal inactivation of the enzyme. In the 0-40°C interval, a value of 87 kJ/mol for the energy of activation of the reaction (Ea) has been calculated. Studies about the effect of temperature on PhPNPase stability have shown that this enzyme is a quite thermolabile protein; in fact, the Ea of the thermal inactivation reaction in the 30-70°C interval, is 96.7 kJ/mol, a value significantly lower than those observed for other proteins isolated from mesophilic and thermophilic sources. The thermostability of this enzyme has also been investigated by spectroscopic analysis. UV-melting curves have shown a temperature for half-denaturation of 46°C, a value significantly higher than that found for the maximum catalytic activity. These results indicate that the catalitic centre of PhPNPase is less stable of the overall protein structure.

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Aye, Armande Mireille. "Mise en évidence du système de communication "Quorum Sensing" impliquant les AHLs chez des bactéries marines isolées de la Méditerranée." Thesis, Toulon, 2015. http://www.theses.fr/2015TOUL0002/document.

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Le contrôle du biofouling sur des surfaces inertes immergées ou en atmosphère humide est une nécessité dans le secteur marin, tant pour des raisons économiques qu’environnementales. La formation de biofilm microbien, étape préalable à la formation du biofouling, est souvent intrinsèquement liée chez les bactéries au système de communication “Quorum Sensing” (QS). Chez certaines bactéries Gram négatif, le QS est basé sur la perception de petites molécules diffusibles appelées N- Acyl Homosérine Lactones (AHLs). L’une des stratégies antifouling en voie de développement de nos jours repose sur l’inhibition du QS bactérien. L’objectif de cette thèse est d’utiliser certaines bactéries marines afin d’identifier des molécules anti-QS capables de perturber la formation de biofilm. Ce travail a donc porté sur la mise en évidence de molécules AHLs impliquées dans le QS chez certaines bactéries marines isolées de la rade de Toulon, l’étude de la modulation de certains phénotypes dont la formation du biofilm, par ces molécules et, la mise en place d’un test préliminaire d’inhibition du QS. Parmi les trois bactéries isolées de la rade de Toulon (TC8, TC14 et TC15) du genre Pseudoalteromonas, connues pour produire de nombreuses molécules actives, et testées pour leur capacité à sécréter des AHLs, seule Pseudoalteromonas sp. TC15 a produit la C12-HSL. P. ulvae TC14, capable de produire un biofilm conséquent et de la violacéine, ne produit aucune AHL. Afin d’évaluer la possibilité d’utiliser une bactérie marine comme outil de criblage anti-QS, interférant avec les AHLs et les conséquences sur son biofilm, des AHLs exogènes ont été testées sur la production de violacéine, la formation de biofilm et la mobilité de TC14. Certaines AHLs ont montré qu’elles pouvaient réguler la production de violacéine et la formation de biofilm chez TC14, suggérant l’existence d’un récepteur AHLs fonctionnel. Des tests préliminaires d’inhibition du QS ont été effectués avec des molécules commerciales et des analogues synthétiques. La 3-oxo-C6-HSL commerciale, ainsi que l’esculétine et la p- benzoquinone, connues pour interférer avec le QS bactérien, ont été capables d’inhiber la production de violacéine ainsi que la formation de biofilm de TC14 à des concentrations n’affectant pas sa croissance. Cette étude suggère donc que P. ulvae TC14 pourrait être utilisée comme un outil de recherche de molécules anti-QS en conditions proches de celles trouvées dans l’environnement marin, et ce dans le but d’être ultérieurement testées sur la formation de biofilm. L’objectif à plus long terme reste de trouver un moyen de limiter la formation du biofilm en utilisant des molécules non toxiques pour l’environnement
The biofouling control on immersed inert surfaces or in moist atmosphere is a necessity in the marine sector for both economic and environmental reasons. Microbial biofilm formation, the initial step of biofouling development, is intrinsically linked to the communication system “Quorum sensing” (QS). In some Gram negative bacteria, QS is based on the perception of small diffusible signaling molecules called Acyl Homoserine Lactones (AHLs). The inhibition of bacterial QS is part of the different antifouling strategies currently developed. This present work focused on the detection of AHLs molecules involved in this communication system in bacteria isolated from Toulon harbor and the study of modulation of some phenotypes, including biofilm formation, by these molecules as well as the development of a preliminary anti-QS assay. Three marine bacteria isolated from Toulon harbor (TC8, TC14 and TC15), belonging to the Pseudoalteromonas genus, known to synthesize many active molecules, have been tested for their ability to produce AHLs. Only Pseudoalteromonas sp. TC15 produced the C12-HSL. P. ulvae TC14 a violacein-producing and biofilm-forming bacteria, did not secrete any AHLs. Few marine bacteria are used as an anti-QS screening tool, especially by interfering with AHLs with the goal of studying the consequences on biofilm formation. In order to evaluate the possibility to use TC14 with this purpose, exogenous AHLs were tested on the violacein production, the biofilm formation and the motility of TC14. Some AHLs were able to regulate violacein production and biofilm formation suggesting the presence of a functional AHLs receptor in TC14. Preliminary QS inhibition assays were performed with commercial molecules and synthetic analogues. The commercial 3-oxo-C6-HSL as well as esculetin and p-benzoquinone, known to interfere with bacterial QS, were able to inhibit QS and biofilm formation at a non-toxic concentration. Overall, this study suggests that the marine strain P. ulvae TC14 may be used as a tool for the detection of anti-QS molecules in conditions closed to the marine environment. These molecules may subsequently be tested on the biofilm formation of marine bacteria. The long term objective is to find a way to limit biofilm formation, using non-toxic molecules for the environment

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Wilmes, Boris [Verfasser]. "Proteomanalyse und Bioprozessentwicklung des psychrophilen, marinen Bakteriums Pseudoalteromonas haloplanktis TAC125 / Boris Wilmes." Greifswald : Universitätsbibliothek Greifswald, 2011. http://d-nb.info/1010980351/34.

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Jouault, Albane. "Altérocine : une protéine antibiofilm secrétée par la bactérie marine Pseudoalteromonas sp. 3J6." Electronic Thesis or Diss., Lorient, 2019. http://www.theses.fr/2019LORIS588.

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Le biofilm est un mode de vie qui confère aux bactéries une protection contre les agents antimicrobiens et pose un problème de santé publique qui nécessite de trouver une alternative aux traitements actuels. La bactérie marine Pseudoalteromonas sp. 3J6 et ses exoproduits (SN3J6) montrent une activité antibiofilm contre des bactéries marines et terrestres. Une protéine, nommée altérocine, a été extraite du SN3J6. Bien que présente chez plusieurs autres souches de Pseudoalteromonas, son rôle est encore inconnu dans les bases de données. Ce projet a été consacré à l’étude de l’altérocine. Les caractéristiques de cette protéine ainsi que celles de son gène, alt, ont dans un premier temps été étudiées. Le gène alt n’est pas organisé en opéron et plusieurs promoteurs potentiels ont été identifiés. Il est exprimé préférentiellement durant la phase stationnaire. Il code une protéine de 139 résidus incluant un peptide signal prédit, qui permettrait la sécrétion de l’altérocine mature (119 résidus). Aucune homologie de séquence n’a été observée entre l’altérocine et les protéines de fonction connue des bases de données. Afin de détecter plus facilement l’altérocine dans le surnageant de culture, des anticorps anti-altérocine ont été obtenus. Nous avons dans un second temps confirmé l’activité antibiofilm de l’altérocine par une production hétérologue chez une autre souche de Pseudoalteromonas et en comparant les biofilms obtenus en présence des surnageants de culture de cette souche et de sa souche mère. Nous avons montré que l’altérocine est un nouveau type de protéine antibiofilm dont la structure et le mode d’action restent à déterminer pour l’utiliser comme agent antibiofilm
The biofilm lifestyle gives bacteria a protection against antibacterial agents and leads to public health problems that require an alternative to current treatments. The marine bacterium Pseudoalteromonas sp. 3J6 and its exoproducts (SN3J6) display an antibiofilm activity against various bacteria from marine or terrestrial origin. A protein from SN3J6, named alterocin, was partially purified. Although the protein is found in several other Pseudoalteromonas strains, its function remains unknown. In this work, we studied the alterocin. We investigated the protein and gene characteristics at first. The gene alt, coding alterocin, is not part of an operon and several potential promoters were identified. According to our results, its expression seems subject to regulation as it is mainly expressed in stationary phase. It encodes a 139-residue protein with a putative leader peptide, which would allow the secretion of mature alterocin as a 119-residue protein. No sequence homology has been found between alterocin and other proteins of known function in data bases. Anti-alterocin antibodies were produced for an easily detection method. In a second time, we confirmed the antibiofilm activity of alterocin by heterologous production in another Pseudoalteromonas strain and comparing biofilms obtained in the presence of culture supernatants of either this strain or the parental strain. In this work, we showed that the alterocin is a new type of antibiofilm protein whose structure and mechanism of action remain to be elucidated to use it as antibiofilm agent

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Egan, Suhelen Microbiology &amp Immunology UNSW. "Production and regulation of fouling inhibitory compounds by the marine bacterium Pseudoalteromonas tunicata." Awarded by:University of New South Wales. Microbiology and Immunology, 2001. http://handle.unsw.edu.au/1959.4/17838.

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The marine surface-associated bacterium Pseudoaltermonas tunicata, produces a range of compounds that inhibit fouling organisms, including invertebrate larvae, bacteria, algal spores and fungi. In addition to these antifouling compounds P. tunicata cells produce both a yellow and a purple pigment. The aim of this study was to further characterise the antifouling activities, their regulation and relationship with pigmentation, and the ecological significance of P. tunicata and related organisms. It was discovered that the anti-algal compound was extracellular, heat sensitive, polar and between 3 and 10 kDa in size. The anti-fungal compound was found to be the yellow pigment and active against a wide range of fungal and yeast isolates. Chemical analysis suggests that this compound consists of a carbon ring bound to a fatty-acid side chain. Genetic analysis supports the chemical data for the active compound as a mutant in a gene encoding for a long-chain fatty-acid CoA ligase was deficient for anti-fungal activity. To address the regulation of antifouling compounds and their relationship to pigmentation transposon mutagenesis of P. tunicata was performed. Mutants lacking the yellow pigment displayed a reduced ability to inhibit fouling organisms. Further analysis of these mutants identified genes involved with the synthesis and regulation of synthesis of pigment and antifouling compounds. One of these mutants was disrupted in a gene (wmpR) with similarity to the transcriptional regulators ToxR from Vibrio cholerae and CadC from Escherichia coli. Analysis of global protein expression using two-dimensional gel electrophoresis showed that WmpR is essential for the expression of at least fifteen proteins important for the synthesis of fouling inhibitors. The ecological significance of antifouling bacteria was addressed by assessing the antifouling capabilities of a collection of bacteria isolated from different marine surfaces. Overall, isolates from living surfaces displayed more antifouling traits then strains isolated from non-living surfaces. Five dark-pigmented strains originating from the alga Ulva lactuca were further studied. Phylogenetic and phenotypic analysis revealed that they were all members of the genus Pseudoalteromonas and were closely related to P. tunicata. Two strains represented a novel species within the genus and were taxonomically defined as P. ulvae sp. nov.

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Stelzer, Sacha Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "WmpR regulation of antifouling compounds and iron uptake in the marine bacterium Pseudoalteromonas tunicata." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/29354.

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The dark-green pigmented marine bacterium Pseudoalteromonas tunicata produces several extracellular compounds against a range of common fouling organisms including bacteria, fungi, protozoa, diatoms, invertebrate larvae and algal spores. The regulator WmpR, which has N-terminal similarity to ToxR from Vibrio cholerae and CadC from Escherichia coli, controls all of the pigment and antifouling phenotypes. These compounds appear at the onset of stationary phase. The role of WmpR as a stationary phase regulator in P. tunicata was investigated in this thesis. Starvation and stress studies demonstrated that WmpR does not appear to control genes necessary for survival during carbon, phosphate or nitrogen starvation and UV/hydrogen peroxide stress. Intriguingly, phosphate starvation caused pigmentation of wmpR mutant (D2W2) logarithmic phase cells, suggesting a second regulation of the pigments (and thus antifouling compounds) that could be mediated by the PhoR/B twocomponent regulatory system. Proteomic analysis using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) found that 11 proteins were differentially regulated by WmpR, and the identities of some of these proteins suggested a role for WmpR as a general stationary phase regulator rather than a specific starvation or stress regulator. Gene expression studies using RNA-arbitrarily primed PCR introduced a new role for WmpR as a regulator of iron acquisition; a TonB-dependant outer membrane receptor gene and a non-ribosomal peptide synthetase (NRPS) gene were up-regulated in the stationary phase Wt strain compared to the D2W2 strain. An assay for iron-binding activity supported the proposal that the NRPS may be making a siderophore. Further studies demonstrated that WmpR is required for survival under long-term low-iron conditions and that the pigments and antifouling genes are down-regulated during low-iron, while biofilm formation is up-regulated. WmpR also appears to constitutively regulate the production of iron-binding compounds, a novel regulation of iron acquisition that has not been seen in other organisms studied so far. A model is proposed that describes WmpR as responding to environmental signals, including iron, and co-ordinating the expression of a complex regulon including a number of genes involved in iron acquisition, general stationary phase physiology and bioactive secondary metabolite production.

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Ten, Doeschate Kim. "Pseudoalteromonas sp. strain C4 as a probiotic for farmed South African abalone, Haliotis midae." Doctoral thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/4340.

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Includes bibliographical references (leaves 135-154).
The objective of this study was to identify a potential probiotic bacterium that increased the growth and decreased the susceptibility of farmed abalone to pathogenic bacterial infection. The mechanism by which the probiotic is able to increase growth rates and reduced susceptibility to pathogen infection was investigated. A number of bacterial strains were isolated from the digestive tract of Haliotis midae that are capable of degrading a wide variety of different polysaccharides (Erasmus, 1996). Strain C4 was selected for further investigation as a result of its ability to degrade alginate since H. midae is predominantly fed a kelp diet of which the major component is alginate.

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Simon, Marjolaine. "Lutte contre les biofilms de Pseudomonas aeruginosa dans le contexte de la mucoviscidose." Thesis, Lorient, 2015. http://www.theses.fr/2015LORIS364.

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Pseudomonas aeruginosa est un pathogène opportuniste induisant des infections chroniques chez les patients atteints de mucoviscidose. L'éradication de ces infections est presque impossible à l'âge adulte du fait de la formation de biofilms dans les poumons des patients. Les traitements antibiotiques actuels sont peu efficaces contre les biofilms car ce mode de vie assure d'une part la protection des bactéries contre les agents anti-microbiens par l'intermédiaire de la matrice extracellulaire, et favorise d'autre part l'émergence de mécanismes de résistance. Il est donc essentiel de trouver des alternatives thérapeutiques. La bactérie marine Pseudoalteromonas sp. 3J6 sécrète une molécule à activité anti-biofilm efficace contre la souche de laboratoire P. aeruginosa PA01 et les souches cliniques P. aeruginosa MUC-N1, MUC-N2 et MUC-P4. Ces souches ont été caractérisées aux niveaux de leur formation de biofilms in vitro et de leur virulence . Ceci a montré que ces souches sont très différentes les unes des autres et qu'une seule souche, telle que la souche de laboratoire PA01, ne peut pas être représentative des profils observés. Il est donc nécessaire de mener les études anti-biofilms sur plusieurs souches, telles que celles que nous avons sélectionnées. Le potentiel thérapeutique du surnageant de culture (SNa.Js} de Pseudoalteromonas sp. 3J6 et son extrait (Ea.Js} a été étudié en évaluant leur toxicité, la réponse inflammatoire, leur impact sur la production de facteurs de virulence et leur potentiel thérapeutique . SNa.Js et Ea.Js n'étaient pas toxiques vis-à-vis des modèles testés, n'induisaient pas de réponse inflammatoire dans les poumons de souris et n'augmentaient pas la production par P. aeruginosa des facteurs de virulence quantifiés. De plus, SNa.Js s'est avèré être aussi efficace que l'antibiotique ciprofloxacine pour traiter une infection à P. aeruginosa MUC-N2 in vivo sur modèle murin. Ces résultats sont encourageants quant à un potentiel thérapeutique de la molécule à activité anti-biofilm pour contribuer au traitement des infections à P. aeruginosa chez les patients atteints de mucoviscidose
Pseudomonas aeruginosa is an opportunistic pathogen leading to chronic infections in patients suffering of cystic fibrosis. Eradication of these infections is almost impossible in adults because of biofilm formation in patient's lungs. Current antibiotics treatments are not efficient enough against biofilms because this lifestyle first protects bacteria from antimicrobial agents via the biofilm extracellular matrix and secondly promotes the emergence of antibiotic resistance mechanisms. lt is therefore essential to find therapeutic alternatives . The marine bacterium Pseudoalteromonas sp. 3J6 secretes an anti-biofilm molecule active against the laboratory P. aeruginosa PA01 strain and the P. aeruginosa clinical strains MUC-N1, MUC-N2 and MUC P4. These strains were characterized at the levels of in vitro biofilm formation, and of their virulence. This part of the research work highlighted that these strains are different from one to another and that a single strain, such as the laboratory strain PA01, cannot be representative of the various patterns. Anti-biofilm studies have thus to be performed on several strains, such as the ones we selected. The therapeutic potential of the culture supernatant (SNa.Js} of Pseudoalteromonas sp. 3J6 and its extract Ea.Js was studied by evaluating their toxicity, inflammatory response, impact on virulence factors production, and therapeutic efficiency. SNa.Js and Ea.Js were not taxie against the tested models; did not induce inflammatory response in mice lungs, and did not enhance virulence factor production by clinical P. aerugonisa strains. Moreover, SNa.Js was as efficient as the ciprofloxacin antibiotic to treat an in vivo infection by P. aeruginosa MUC-N2 on mice. These results are encouraging as for a therapeutic potential of the anti-biofilm molecule to contribute at the treatment of P. aeruginosa infections of cystic fibrosis patients

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Van, Truong Le. "Characterization of the pectinolytic enzymes of the marine psychrophilic bacterium Pseudoalteromonas haloplanktis strain ANT-505." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=984430180.

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Mai-Prochnow, Anne Gerda Erna Biotechnology &amp Bio-molecular Sciences UNSW. "Autolysis in the development and dispersal of biofilms formed by the marine bacterium Pseudoalteromonas tunicata." Awarded by:University of New South Wales. Biotechnology and Bio-molecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/25537.

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The marine bacterium Pseudoalteromonas tunicata produces target-specific inhibitory compounds against bacteria, algae, fungi and invertebrate larvae and is frequently found in association with living surfaces in the marine environment. This study examined the ability of P. tunicata to form biofilms under continuous culture conditions within the laboratory. P. tunicata biofilms exhibited a characteristic architecture consisting of differentiated microcolonies surrounded by water-channels. Interestingly, a repeatable pattern of cell death in the centre of microcolonies was observed. The antibacterial and autolytic protein, AlpP, produced by P. tunicata was found to be involved in this biofilm killing and a

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Lizano, Chehin Omar Anthony. "Caracterización Bioquímica de la actividad Lipolítica de Pseudoalteromonas Atlantica Aislada de la Bahía de Paracas." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2012. https://hdl.handle.net/20.500.12672/3221.

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Con el objetivo de caracterizar bioquímicamente la actividad lipolítica de Pseudoalteromonas atlantica PAR 2, aislada de la Bahía de Paracas (Ica), se procedió a cultivar la bacteria en medio LB (Luria-Bertani) a temperatura ambiente durante 24 horas. Para determinar la actividad lipolítica de la Pseudoalteromonas atlantica PAR 2, se utilizó agar SW 5 % con tributirina 1 % y se incubó a temperatura ambiente por 48 horas; la hidrólisis del sustrato se evidenció por la formación de un halo transparente. Así también, se cuantificó la actividad lipolítica utilizando como sustratos por un lado tween 80 y por otro, aceite de oliva al 1 %; los cuales no fueron degradados; esta respuesta evidenció que la enzima en estudio es una lipasa del grupo VI o esterasa. Por ese motivo, se utilizó como sustrato -nitrofenol acetato en buffer fosfato 25 mM pH 7, el producto liberado se midió por espectrofotometría a 405 m y se obtuvo una actividad enzimática de 79,32 mol/mL y una actividad específica de 661,00 mol/mg de proteína en el extracto crudo. Pseudoalteromonas atlantica PAR 2 produce una lipasa del grupo VI o esterasa, la cual además presenta actividad óptima a 20 ºC, pH 7 y concentración salina 5 %. -- Palabras clave: Pseudoalteromonas atlantica, actividad lipolítica, esterasa, -nitrofenol acetato.
-- In order to characterize biochemically the lipolytic activity of Pseudoalteromonas atlantica PAR 2, isolated from the Bay of Paracas (Ica), it was proceeded to grow the bacteria in LB medium (Luria-Bertani) at environment temperature during 24 hours. To determine lipolytic activity of Pseudoalteromonas atlantica PAR 2, SW 5 % agar with tributyrin 1 % was incubated at environment temperature for 48 hours, where substrate hydrolysis was evidenced by the formation of a transparent halo. Additionally, lipolytic activity was quantified using as substrates Tween 80 on one side and on the other, olive oil, 1%, which were not degraded, this response revealed that the enzyme under study is a lipase or esterase group VI. For that reason, was used as substrate -nitrophenol acetate in 25 mM phosphate buffer pH 7, the released product was measured by spectrophotometry at 405 m and was obtained 79,32 mol/mL as enzymatic activity, and 661,00 mol/mg protein as specific activity in the crude extract. Pseudoalteromonas atlantica PAR 2 produces a lipase group VI or esterase, which also has optimal activity at 20 °C, pH 7 and 5% salt concentration. -- Keywords: Pseudoalteromonas atlantica, lipolytic activity, esterase, -nitrophenol acetate
Tesis

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Ayé, Armande Mireille. "Mise en évidence du système de communication "Quorum Sensing" impliquant les AHLs chez des bactéries marines isolées de la Méditerranée." Electronic Thesis or Diss., Toulon, 2015. http://www.theses.fr/2015TOUL0002.

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Le contrôle du biofouling sur des surfaces inertes immergées ou en atmosphère humide est une nécessité dans le secteur marin, tant pour des raisons économiques qu’environnementales. La formation de biofilm microbien, étape préalable à la formation du biofouling, est souvent intrinsèquement liée chez les bactéries au système de communication “Quorum Sensing” (QS). Chez certaines bactéries Gram négatif, le QS est basé sur la perception de petites molécules diffusibles appelées N- Acyl Homosérine Lactones (AHLs). L’une des stratégies antifouling en voie de développement de nos jours repose sur l’inhibition du QS bactérien. L’objectif de cette thèse est d’utiliser certaines bactéries marines afin d’identifier des molécules anti-QS capables de perturber la formation de biofilm. Ce travail a donc porté sur la mise en évidence de molécules AHLs impliquées dans le QS chez certaines bactéries marines isolées de la rade de Toulon, l’étude de la modulation de certains phénotypes dont la formation du biofilm, par ces molécules et, la mise en place d’un test préliminaire d’inhibition du QS. Parmi les trois bactéries isolées de la rade de Toulon (TC8, TC14 et TC15) du genre Pseudoalteromonas, connues pour produire de nombreuses molécules actives, et testées pour leur capacité à sécréter des AHLs, seule Pseudoalteromonas sp. TC15 a produit la C12-HSL. P. ulvae TC14, capable de produire un biofilm conséquent et de la violacéine, ne produit aucune AHL. Afin d’évaluer la possibilité d’utiliser une bactérie marine comme outil de criblage anti-QS, interférant avec les AHLs et les conséquences sur son biofilm, des AHLs exogènes ont été testées sur la production de violacéine, la formation de biofilm et la mobilité de TC14. Certaines AHLs ont montré qu’elles pouvaient réguler la production de violacéine et la formation de biofilm chez TC14, suggérant l’existence d’un récepteur AHLs fonctionnel. Des tests préliminaires d’inhibition du QS ont été effectués avec des molécules commerciales et des analogues synthétiques. La 3-oxo-C6-HSL commerciale, ainsi que l’esculétine et la p- benzoquinone, connues pour interférer avec le QS bactérien, ont été capables d’inhiber la production de violacéine ainsi que la formation de biofilm de TC14 à des concentrations n’affectant pas sa croissance. Cette étude suggère donc que P. ulvae TC14 pourrait être utilisée comme un outil de recherche de molécules anti-QS en conditions proches de celles trouvées dans l’environnement marin, et ce dans le but d’être ultérieurement testées sur la formation de biofilm. L’objectif à plus long terme reste de trouver un moyen de limiter la formation du biofilm en utilisant des molécules non toxiques pour l’environnement
The biofouling control on immersed inert surfaces or in moist atmosphere is a necessity in the marine sector for both economic and environmental reasons. Microbial biofilm formation, the initial step of biofouling development, is intrinsically linked to the communication system “Quorum sensing” (QS). In some Gram negative bacteria, QS is based on the perception of small diffusible signaling molecules called Acyl Homoserine Lactones (AHLs). The inhibition of bacterial QS is part of the different antifouling strategies currently developed. This present work focused on the detection of AHLs molecules involved in this communication system in bacteria isolated from Toulon harbor and the study of modulation of some phenotypes, including biofilm formation, by these molecules as well as the development of a preliminary anti-QS assay. Three marine bacteria isolated from Toulon harbor (TC8, TC14 and TC15), belonging to the Pseudoalteromonas genus, known to synthesize many active molecules, have been tested for their ability to produce AHLs. Only Pseudoalteromonas sp. TC15 produced the C12-HSL. P. ulvae TC14 a violacein-producing and biofilm-forming bacteria, did not secrete any AHLs. Few marine bacteria are used as an anti-QS screening tool, especially by interfering with AHLs with the goal of studying the consequences on biofilm formation. In order to evaluate the possibility to use TC14 with this purpose, exogenous AHLs were tested on the violacein production, the biofilm formation and the motility of TC14. Some AHLs were able to regulate violacein production and biofilm formation suggesting the presence of a functional AHLs receptor in TC14. Preliminary QS inhibition assays were performed with commercial molecules and synthetic analogues. The commercial 3-oxo-C6-HSL as well as esculetin and p-benzoquinone, known to interfere with bacterial QS, were able to inhibit QS and biofilm formation at a non-toxic concentration. Overall, this study suggests that the marine strain P. ulvae TC14 may be used as a tool for the detection of anti-QS molecules in conditions closed to the marine environment. These molecules may subsequently be tested on the biofilm formation of marine bacteria. The long term objective is to find a way to limit biofilm formation, using non-toxic molecules for the environment

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Dheilly, Alexandra. "Biofilms bactériens marins multi-espèces : mise en évidence d'un effet antagoniste." Lorient, 2007. http://www.theses.fr/2007LORIS091.

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Les salissures marines ou biofouling sont à l’origine de problèmes écologiques et de pertes économiques. L’une des premières étapes intervenant dans le biofouling est la formation de biofilms bactériens, c'est-à-dire de communautés de bactéries adhérées irréversiblement à un support et enveloppées dans une matrice de polymères extracellulaires. De plus en plus de travaux ont pour but d’étudier ces communautés bactériennes dans la perspective de contrôler, d’éviter ou de limiter leur formation. Ce travail a été consacré à l’étude in vitro du développement de biofilms marins pluri-espèces dans un système dynamique, et à la relation existant entre la formation du biofilm et les propriétés phénotypiques des différentes souches bactériennes utilisées. Deux étapes clés de la formation d’un biofilm bactérien ont été investiguées : l’adhésion des bactéries et la croissance du biofilm. L’étude des biofilms mono-espèces suggère que la mobilité et la production d’exoproduits par les bactéries induisent l’établissement de biofilms plus épais formant des agrégats bactériens. En revanche, nos résultats n’ont pas permis d’établir un lien entre la structure des biofilms et la production ou non de molécules de communication de type N-acyl-L-homoserine lactone ou furanosyl borate diester. Des biofilms pluri-espèces ont été réalisés à partir de trois couples bactériens, tous contenant Pseudoalteromonas 3J6. Les résultats montrent que le couple Pseudoalteromonas 3J6-Bacillus 4J6 produit un biofilm mixte (Bacillus 4J6 : 38 %, Pseudoalteromonas 3J6 : 62 %), dont les cellules de Bacillus 4J6 sont localisées tout autour des microcolonies de Pseudoalteromonas 3J6. En revanche, la bactérie Pseudoalteromonas 3J6 est très largement majoritaire (90-95 %) dans les biofilms résultant de son inoculation avec Vibrio D01 ou Paracoccus 4M6. Ceci met en évidence un effet antagoniste de Pseudoalteromonas 3J6 vis-à-vis de ces deux souches bactériennes. Le mécanisme d’inhibition de Pseudoalteromonas 3J6 a ensuite été analysé sur les cellules bactériennes planctoniques et sessiles. Les résultats suggèrent un effet spécifiquement anti-biofilm dû aux composés extracellulaires produits par cette souche. Ces composés, probablement de nature protéique, agissent dès la première étape du biofilm en diminuant l’adhésion des cellules au support. Enfin, les effets de ces composés extracellulaires montrent des similarités à ceux obtenus avec deux biocides commerciaux, molécules utilisées dans les peintures antifouling. En effet, l’ajout de biocides diminue le pouvoir d’adhésion des bactéries et inhibe la croissance du biofilm. En outre, les biocides augmentent la mortalité des cellules au sein du biofilm
Marine fouling or biofouling leads to ecologic damages and economic losses. One of the earliest stages of biofouling is the formation of a bacterial biofilm, consisting of an assemblage of irreversibly adhered microbial cells on a surface, and enclosed in a hydrated matrix of extra-cellular polymeric substances. Many works currently aim at studying biofilm development in order to control, prevent or limit their formation. In this work, we investigated the in vitro development of multi-species biofilms of marine bacteria in a dynamic system, and the relationship between biofilm formation and phenotypic properties of each bacterial strain used. Biofilm formation was analysed at two levels: cell adhesion and biofilm growth. Study of mono-species biofilms suggested that motility and exopolymer production by bacteria induce thick biofilms contains microcolonies. However, our results did not allow to establish a link between biofilm structure and ability of the bacteria to produce or not communication molecules such as N-acyl-L-homoserine lactone or furanosyl borate diester. Mixed biofilms were produced from three strain couples, all of them including Pseudoalteromonas 3J6. The results show that in Pseudoalteromonas-Bacillus biofilms, Bacillus 4J6 cells were located in between Pseudoalteromonas 3J6 microcolonies (Bacillus 4J6: 38 %, Pseudoalteromonas 3J6: 62 %). By contrast, development of Vibrio D01 and Paracoccus 4M6 strains was strongly impaired in Pseudoalteromonas-containing biofilms (Pseudoalteromonas 3J6: 90/95 %). Theses results revealed an inhibitory effect of Pseudoalteromonas 3J6 towards Vibrio D01 and Paracoccus 4M6 strains. The inhibition mechanism of Pseudoalteromonas 3J6 was then studied on planktonic and sessile cells. The results suggest a biofilm-specific effect relying on extracellular compounds produced by this bacterium. Also, we observed that theses compounds are probably of proteic nature and that they affect the first step of biofilm formation by impairing the cell adhesion onto the surface. Finally, there was a similarity between effects of Pseudoalteromonas 3J6 exoproducts and commercials biocides, which are used in antifouling paints. Indeed, addition of biocides led to diminution of cell adhesion power and inhibition of biofilm growth. Besides, biocides increased mortality inside biofilms

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Sousa, Thiciana da Silva. "Micro-organismos marinhos produtores de metabÃlitos secundÃrios biologicamente ativos." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10163.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Este trabalho descreve o estudo quÃmico e biolÃgico dos extratos das bactÃrias marinhas Pseudoalteromonas sp., Micromonospora sp., Streptomyces sp. e Kocuria sp., visando o isolamento e a elucidaÃÃo estrutural de novos constituintes bioativos. A investigaÃÃo quÃmica realizada com a bactÃria Pseudoalteromonas sp. resultou no isolamento de um pigmento vermelho identificado como prodigiosina e de dois Ãcidos biliares conhecidos como Ãcido desoxicÃlico e Ãcido cÃlico. A prodigiosina foi testada frente a quatro linhagens de cÃlulas tumorais e apresentou valores de IC50 semelhantes ao padrÃo positivo. O estudo quÃmico de Micromonospora sp. resultou no isolamento de quatro novas antraciclinonas: 4,6,11-triidroxi-9-propriltetraceno-5,12-diona; 4-metoxi-9-propiltetraceno-6,11-diona; 7,8,9,10-tetraidro-9-hidroxi-4-metoxi-9-propiltetra-ceno-6,11-diona e 10β-metoxicarbonil-7,8,9,10-tetraidro-4,6,7α,9α,11âpentaidroxiâ9âpropil-tetraceno-5,12-diona. Esses compostos foram avaliados quanto a sua atividade anti-tumoral frente a linhagem celular HCT-8, dois dos quais mostraram citotoxidade moderada com valores de IC50 de 12,74 e 6,18 M. O estudo da bactÃria Streptomyces sp. possibilitou o isolamento de uma ditiolpirrolidina cuja estrutura foi estabelecida como 5-oxo-6-(N-metilformamida)-4,5- diidro-1,2-ditiol[4,3-b]pirrol. Esse metabÃlito teve sua atividade citotÃxica testada frente a seis linhagens celulares tumorais, mostrando forte atividade com IC50 de 1,66, 1,05 e 1,52 ÂM para as linhagens de prÃstata metastÃtica, carcinoma de ovÃrio e glioblastoma, respectivamente. O estudo de Kocuria sp. resultou no isolamento de um novo peptÃdeo denominado como kocurina. Esse composto teve sua atividade antimicrobiana testada frente a vÃrias bactÃrias e fungos patogÃnicos, incluindo cepas de Staphylococcus aureus resistentes a meticilina (MRSA) e cepas de Staphylococcus aureus resistentes a tiazomicina. Kocurina inibiu fortemente o crescimento de MRSA MB5393 com valores de CIM de 0,25Âg/mL, alÃm de exibir atividade antibacteriana contra as bactÃrias Bacillus subtilis e Enterococcus faecium. As estruturas de todos os compostos isolados neste trabalho foram determinadas empregando mÃtodos espectroscÃpicos tais como RMN 1H e 13C (1D e 2D), espectrometria de massas e infravermelho.
This work describe the chemical and biological investigation of the extracts from the marine bacterias Pseudoalteromonas sp., Micromonospora sp., Streptomyces sp. and Kocuria sp., aiming the isolation and structural elucidation of new bioactive constituents. The chemical investigation carried out with the bacteria Pseudoalteromonas sp. lead to the isolation a red pigment identified as prodigiosin and two bile acids derivatives known as deoxycholic acid and cholic acid. The prodigiosin was evaluated against four tumor cell lines showing IC50 values similar to the positive control doxorubicin. The chemical study of Micromonospora sp. Resulted in the isolation of four new anthracyclinones designed as 4,6,11-trihydroxy-9-propryltetracene-5,12-dione; 4-methoxy-9-propyltetracene-6,11-dione; 7,8,9,10 - tetrahydro-9-hydroxy-4-methoxy-9-propiltetra-cene-6,11-dione and 10β-Carbomethoxy-7,8,9,10-tetrahydro-4,6,7α,9α,11-pentahydroxy-9-propyltetracene-5,12-dione . The cytotoxic potential of these compounds were evaluated against HCT-8cell line, two of which showed moderate cytotoxicity with IC50 values of 12.74 and 6.18 M, respectively. From Streptomyces sp. strain was isolated a ditiolpyrrolidin, established as 5-oxo-6-(N-methylformamide) -4,5 - dihydro-1,2-dithiol [4,3-b] pyrrole. This secondary metabolite was tested against six tumor cell lines, shown IC50 values of 1.66, 1.05 and 1.52 mM for the metastatic prostate lines, ovarium carcinoma and glioblastoma, respectively. The study of Kocuria sp. lead to the isolation of a new peptide, which was designed as kocurin. This compound was subjected to the tested its antimicrobial assays against several pathogens bacteria and fungal including Staphylococcus aureus strains methicillin resistant (MRSA) and Staphylococcus aureus strains tiazomicin resistant. Kocurin was strongly active against MRSA MB5393 exhibiting a MIC of 0,25Âg/mL, moreover showed antibacterial activity against Bacillus subtilis and Enterococcus faecium. The structures of all isolated compounds in this work were stabilized employing spectroscopic methods such as 1H and 13C NMR (1D and 2D), mass spectrometry and infrared.

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Carrasco, Palma Daniel Alejandro. "Caracterización y especificidad del efecto alguicida de la bacteria marina Pseudoalteromonas sp. AMA-02 sobre microalgas marinas." Tesis, Universidad de Chile, 2005. http://repositorio.uchile.cl/handle/2250/131042.

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Memoria para optar al Título Profesional de Médico Veterinario
Las Floraciones de Algas Nocivas (FAN) en el mar, son fenómenos de gran impacto económico, productivo, sanitario y social. El dinoflagelado tóxico Alexandrium catenella cepa ACC01, fue aislado desde la XIa Región de Aysen, Chile (45º 32´ S, 73º 34´O), un área que fue afectada previamente por Floraciones de Algas Nocivas del tipo paralizante y diarreico. Este dinoflagelado ha sido cultivado y mantenido en el Laboratorio de Toxinas Marinas de la Facultad de Medicina de la Universidad de Chile. A partir de estos cultivos, en el año 2002, se aisló la bacteria marina Pseudoalteromonas sp. cepa AMA-02. Esta bacteria, que normalmente crece en forma saprófita asociada a Alexandrium catenella, al crecerla separada de ella, en un medio de cultivo con nutrientes orgánicos, es capaz de liberar al medio de cultivo sustancias líticas para la microalga de la cual fue aislada. Sin embargo, la actividad lítica no se observa cuando la bacteria, libre de nutrientes orgánicos, es reinsertada en el cultivo de A. catenella ACC01. El efecto lítico observado, es aparentemente específico para las cepas ACC01 y ACC02 de A. catenella, pero no para la microalga no tóxica Heterocapsa sp. cepa SGM01. Las sustancias líticas liberadas al medio de cultivo son capaces de inmovilizar inicialmente al dinoflagelado y promover, posteriormente la lisis celular a través de enzimas hidrolíticas liberadas al medio por la bacteria Pseudoalteromonas sp. cepa AMA-02, normalmente asociadas a la microalga. La caracterización preliminar y purificación de el o los factores liberados al medio de cultivo, responsables de la actividad lítica, demostró que corresponde a un compuesto de características hidrofóbicas, de un peso molecular menor a 1 KDa

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Michel, Gurvan. "Etudes structurales et fonctionnelles de la k-carraghénase de Pseudoalteromonas carrageenovora et de la l-carraghénase d'Alteromonas fortis." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10248.

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Pour comprendre les mecanismes d'hydrolyse et de reconnaissance des carraghenanes, la -carraghenase de p. Carrageenovora (33 kda) et la -carraghenase d'a. Fortis (53 kda) ont ete exprimees dans des souches d'e. Coli avec une etiquette d'histidines, sous leur forme native et marquees aux seleno-methionines. Ces proteines ont ete purifiees par chromatographie d'affinite et cristallisees en utilisant le polyethylene glycol comme agent precipitant. Leur structure ont ete resolues par la methode mad a trois longueurs d'onde en utilisant les proteines marquees aux seleno-methionines. Les modeles ont ete affines a 1,54 a de resolution pour la -carraghenase (r = 17. 8%, r l i b r e = 19. 3%) et 1,60 a pour la -carraghenase (r = 20. 7%, r l i b r e = 22. 3%). La -carraghenase adopte un repliement en sandwich , similaire a celui de la lichenase, seule proteine de la famille 16 de structure connue. Cependant cette proteine presente un site actif en tunnel, topologie observee uniquement dans les cellobiohydrolases, suggerant une adaptation la degradation endo-processive d'un substrat solide. La presence d'un -bulge dans le site actif eclaire d'un jour nouveau l'evolution du clan b des glycoside-hydrolases. La -carraghenase presente un cur en helice droite, avec deux domaines additionnels dans la region c-terminale. Les acides amines potentiellement impliques dans la catalyse et la reconnaissance du -carraghenane ont ete identifies. L'influence du nacl sur l'activite enzymatique est expliquee par la presence d'un ion sodium et un ion chlorure. La cinetique de degradation enzymatique du -carraghenase, suivie en solution par rmn et en phase solide par met, a montre que les -carraghenases agissent par inversion de configuration anomerique et selon un mecanisme endo-processif.

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Kawai, Soichiro. "Development of low-temperature protein production systems by using cold-adapted bacteria, Shewanella livingstonensis Ac10 and Pseudoalteromonas nigrifaciens Sq02." Kyoto University, 2020. http://hdl.handle.net/2433/253510.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第22665号
農博第2420号
新制||農||1080(附属図書館)
学位論文||R2||N5296(農学部図書室)
京都大学大学院農学研究科応用生命科学専攻
(主査)教授栗原達夫, 教授小川順, 教授阪井康能
学位規則第4条第1項該当

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Leroy, Céline. "Lutte contre les salissures marines : approche par procédés enzymatiques." Toulouse, INSA, 2006. http://www.theses.fr/2006ISAT0002.

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L'adhésion de salissures marines sur les structures immergées en eau de mer cause de sévères dégâts et problèmes économiques par une accélération de la dégradation des matériaux et une diminution des performances industrielles. Nous avons choisi de tester le potentiel antisalissure de préparations enzymatiques commerciales de type hydrolases (protéases, glycosidases et lipases) sur les premières étapes d'adhésion des salissures marines : le biofilm bactérien. Un test d'évaluation de propriétés antisalissures concernant l'adhésion d'une bactérie marine du genre Pseudoalteromonas sp. D41 en microplaque et en eau de mer naturelle stérile a été mis au point. Ce test est adapté au criblage d'activités de prévention ou de nettoyage d'un biofilm marin et permet de tester la toxicité des préparations enzymatiques sur les cellules non adhérées. Les taux d'inhibition exprimés en fonction du logarithme de la concentration en enzyme consiste en une courbe sigmoïde de type dose-réponse. Des hydrolases testées, les protéases dont la subtilisine sont les plus efficaces. Un mélange d'activités enzymatiques amylases, lipases et protéases a montré une forte synergie d'activité pour inhiber l'adhésion de Pseudoalteromonas sp. D41 en microplaque. L'étude de la composition de substances polymériques produites par Pseudoalteromonas sp. D41 en fermenteur et au sein d'un biofilm a permis de mieux comprendre la nature des molécules organiques cibles impliquées dans l'inhibition de l'adhésion
Fouling on marine underwater surfaces causes critical and economic problems such as important material biodamages and industrial performances reduction. We chose to test antifouling potential of enzymatic commercial preparations like hydrolases (proteases, glycosidases and lipases) in order to inhibit the first fouling adhesion step: bacterial biofilm formation. An evaluation test of antifouling properties onto marine bacterial adhesion was designed using a mono-incubation of Pseudoalteromonas sp. D41 in microtiter plate and in sterile natural sea water. This test was adapted to screen agents for bacterial adhesion removal or inhibition activities and allowed to test enzymatic preparations toxicity on non adhered bacteria. Inhibition rates according to logarithm of enzymatic preparation concentration exhibits a sigmoid shape like dose-response curves. Among hydrolases, proteases like subtilisin are the most efficient enzymes. The efficiency of amylase, lipase and protease activity mixture was evaluated and showed a high synergistic inhibition on Pseudoalteromonas sp. D41 adhesion in microtiter plate. Studies on polymeric extracellular substances from Pseudoalteromonas sp. D41 in fermentation and in biofilm will be helpful in the understanding of the organic molecules nature involved in the adhesion inhibition

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22

Violot, Sébastien. "Etudes fonctionnelles et structurales de la protéine EED, partenaire cellulaire du virus VIH-1 et de la cellulase « froide » Cel5G de Pseudoalteromonas haloplanktis." Phd thesis, Université Claude Bernard - Lyon I, 2005. http://tel.archives-ouvertes.fr/tel-00091916.

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La protéine humaine EED appartient à la famille des «Polycomb». Elle intervient dans la régulation génique. Elle jouerait aussi un rôle dans le cycle du virus de l'immunodéficience humaine (VIH-1) en participant au transport du complexe de préintégration et en facilitant la réaction d'intégration. EED a été surproduite afin d'être cristallisée seule et en complexe avec les protéines virales IN, MA et Nef. Un modèle de EED a été construit par homologie structurale. D'après nos expériences de « phage display », les régions susceptibles d'interagir avec les partenaires viraux se situent sur des boucles de ce modèle.
La bactérie psychrophile P. haloplanktis produit la cellulase Cel5G. Les structures de cette cellulase seule et en complexe avec le cellobiose, ont été déterminées à haute résolution par remplacement moléculaire. La cellulase Cel5A de la bactérie mésophile E. chrysanthemi a été utilisée comme modèle. Nos résultats permettent de mieux comprendre les déterminants structuraux responsables de l'adaptation des enzymes aux basses températures.

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Violot, Sébastien. "Études fonctionnelles et structurales de la protéine EED, partenaire cellulaire du virus VIH-1 et de la cellulase "froide" Cel5G de Pseudoalteromonas haloplanktis." Lyon 1, 2005. http://tel.archives-ouvertes.fr/docs/00/09/19/16/PDF/These_impression_VIOLOT.pdf.

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La protéine humaine EED appartient à la famille des "Polycomb". Elle intervient dans la régulation génique. Elle jouerait aussi un rôle dans le cycle du virus de l'immunodéficience humaine (VIH-1) en participant au transport du complexe de préintégration et en facilitant la réaction d'intégration. EED a été surproduite afin d'être cristallisée seule et en complexe avec les protéines virales IN, MA et Nef. Un modèle de EED a été construit par homologie structurale. D'après nos expériences de " phage display ", les régions susceptibles d'interagir avec les partenaires viraux se situent sur des boucles de ce modèle. La bactérie psychrophile P. Haloplanktis produit la cellulase Cel5G. Les structures de cette cellulase seule et en complexe avec le cellobiose, ont été déterminées à haute résolution par remplacement moléculaire. La cellulase Cel5A de la bactérie mésophile E. Chrysanthemi a été utilisée comme modèle. Nos résultats permettent de mieux comprendre les déterminants structuraux responsables de l'adaptation des enzymes aux basses températures

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24

Lemoine, Maud. "Effets de la conformation et de l'agrégation du kappa-carraghénane sur les modalités de l'hydrolyse enzymatique par la kappa-carraghénase de Pseudoalteromonas carrageenovora." Paris 6, 2009. http://www.theses.fr/2009PA066190.

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Le kappa-carraghénane est un galactane sulfaté formant des gels. L’agrégation des chaînes de polysaccharides implique une transition conformationnelle d’un état désordonné à un état ordonné. La kappa-carraghénase est une glycoside hydrolase qui hydrolyse les liaisons β(1->4) du polymère. Le mode d’action de la kappa-carraghénase a été caractérisé en fonction des différents états conformationnels et de l’état physique du substrat. Des hydrolyses ont été conduites sur le substrat soluble et en phase hétérogène (solide ordonné ou désordonné). Les résultats ont confirmé le mode endo-processif de l’enzyme qui serait modulé par l’état physique du substrat. L’enzyme a permis d’étudier la conformation du polymère. Une baisse de l’activité a été constatée quand le substrat est en conformation hélice en présence d’iode. Des analyses cinétiques, combinées à la caractérisation de la conformation et de l’iode fixé au kappa-carraghénane, ont montré que la diminution d’activité n’est pas causée par la transition conformationnelle mais par la fixation d’iode sur les chaînes qui masquent les liaisons hydrolysables. Le kappa-carraghénane adopterait donc une conformation en simple hélice.

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Schroeder, Declan Cosmo. "Isolation and characterization of a β(1-4) agarase of an epiphytic bacterial pathogen, Pseudoalteromonas gracilis B9, of the red alga, Gracilaria gracilis." Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4328.

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Violot, Sébastien Haser Richard. "Études fonctionnelles et structurales de la protéine EED, partenaire cellulaire du virus VIH-1 et de la cellulase "froide" Cel5G de Pseudoalteromonas haloplanktis." Villeurbanne : Université Claude Bernard, 2005. http://tel.archives-ouvertes.fr/docs/00/09/19/16/PDF/These_impression_VIOLOT.pdf.

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27

Rau, Jan Erik [Verfasser], Ulrich [Akademischer Betreuer] Fischer, and Olav [Akademischer Betreuer] Grundmann. "Characterisation of inhibitory substances produced by two Pseudoalteromonas species and the cyanobacterial strain Flo1 / Jan Erik Rau. Gutachter: Ulrich Fischer ; Olav Grundmann. Betreuer: Ulrich Fischer." Bremen : Staats- und Universitätsbibliothek Bremen, 2011. http://d-nb.info/1071897691/34.

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Sorieul, Louis. "Pseudoalteromonas sp. NC201, un probiotique isolé en Nouvelle-Calédonie pour l'élevage de la crevette Litopenaeus stylirostris : Caractérisation et impact sur l’état physiologique de la crevette." Thesis, Nouvelle Calédonie, 2017. http://portail-documentaire.unc.nc/files/public/bu/Louis.Sorieul_TheseFinaleCorrigee_2017.pdf.

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La souche Pseudoalteromonas sp. NC201, isolée en Nouvelle-Calédonie, possède des propriétés antibactériennes et probiotiques dans le cadre d’élevages larvaires de crevettes. Ainsi, cette souche bactérienne constitue une alternative à l’utilisation des antibiotiques. Ce travail de thèse a été focalisé sur la caractérisation de NC201 et de son potentiel antimicrobien ainsi que sur l’étude de son effet sur la crevette, Litopenaeus stylirostris lors de challenges expérimentaux. L’analyse du génome de NC201 a révélé la présence de clusters de gènes codants des composés antimicrobiens ainsi que deux amino acides oxydases. Une de ces oxydases a été identifiée comme capable d’inhiber des Vibrio pathogènes de L. stylirostris. Les essais in vivo ont permis de confirmer le rôle probiotique de NC201. En effet NC201 a été responsable d’une amélioration de la survie des animaux lors de stress hypo et hypersalins mais aussi lors de challenge biotique par infection avec V. nigripulchritudo. Le suivi dans l’hémolymphe de NC201 et V. nigripulchritudo a mis en évidence que ces deux bactéries étaient capables individuellement de coloniser l’hémolymphe des animaux, cependant, une exclusion mutuelle des deux bactéries a été observée dans ce compartiment. L’expression de gènes liés à la réponse immunitaire ainsi qu’à la réponse au stress oxydant a été quantifiée suite au traitement probiotique et au challenge avec V. nigripulchritudo. La quantification et l’activité enzymatique de biomarqueurs du stress oxydant ont été mesurées. Les modulations de ces biomarqueurs ont révélé que la souche NC201 conférait aux crevettes un état de santé général plus performant pour répondre à des stress
The Pseudoalteromonas sp. NC201 strain, isolated in New Caledonia, displayed antibacterial and probiotic properties in shrimp hatcheries. This strain is an alternative to antibiotics use. This thesis focused on the characterization of NC201, its antimicrobial potential as well as on the study on its effect on Litopenaeus stylirostris during experimental challenges. The analysis of the complete genome sequence of NC201 revealed multiple clusters coding for potential antimicrobial compounds as well as two amino acid oxidases. One of these oxidases was identified as capable of inhibiting Vibrio pathogenic to L. stylirostris such as V. penaeicida and V. nigripulchritudo. In vivo trials confirmed the probiotic role of NC201 towards L. stylirostris. Indeed NC201 was responsible for higher survival rates in animals confronted to hypo and hypersaline stress as well as to bacterial challenge through infection with V. nigripulchritudo. During experimental infections the presence of NC201 and V. nigripulchritudo was monitored in the shrimp hemolymph. Both bacteria are capable of invading the shrimp’s hemolymph but seemed mutually exclusive in this compartment during the 24 hours following the infection. The expression profile of genes involved in the immune response and the response to oxidative stress were quantified in the hemolymph and hepatopancreas, respectively. Enzymatic activities and quantification of bioindicators of oxydative stress were measured in the hepatopancreas. These modulations highlighted that NC201 induced an increase in the shrimp overall health status leading to enhanced responses to stresses

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Gildenhuys, Carin. "Investigation of the role of the extracellular β-agarase, produced by the bacterial epiphyte Pseudoalteromonas sp. LS2i, in the virulence response towards the agarophyte Gracilaria gracilis." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/4266.

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Includes abstract
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Gracilaria gracilis that grows naturally at Saldanha Bay, South Africa is economically important as a source of agar. The Gracilaria yields from natural beds at Saldanha Bay are however unreliable, and consequently the South African Gracilaria industry has experienced a number of setbacks over the years. The only way a consistent supply can be assured is by mariculture to supplement the natural harvests. In 1993 the Seaweed Research Institute (SRU) found that mariculture of G. gracilis in Saldanha Bay is feasible but that there is potential to improve yields by technical research and development (Anderson et al.1996a). Jaffray and Coyne (1996) developed a pathogenicity assay that demonstrated that agarolytic bacteria isolated from Saldanha Bay Gracilaria induced disease symptoms such as thallus bleaching, while non-agarolytic isolates did not. It is thought that unfavorable environmental conditions such as elevated water temperature and nutrient depletion, which occur during the summer months in the surface layers of the water column in Saldanha Bay, induce the onset of agarase production or result in changes in the bacterial community structure in which agarase-producers become more dominant. By using the pathogenicity assay, Jaffray and Coyne (1996) identified the highly agarolytic Gracilaria gracilis pathogen, Pseudoalteromonas sp. LS2i. The aim of this study was to characterize the bacterial pathogen, Pseudoalteromonas sp. LS2i to further our understanding of virulence regulation and specifically, the role of the agarase enzymes in the process of seaweed-pathogen interaction. Two agarolytic clones, pEB1 and pJB1, were obtained after constructing and screening a Pseudoalteromonas sp. LS2i genomic library in Esherichia coli. Restriction enzyme mapping suggested that both clones contain the same agarase gene. Southern hybridization studies confirmed the origin of the cloned DNA and sequencing studies revealed the 1062 bp ORF, putative promoter region, putative ribosome binding site and putative transcriptional start point of the cloned agarase gene. The ORF showed sequence identity to several other β-agarases and was identified as a member of the GH-16 family of glycoside hydrolases. The agarase was purified from the E. coli JM109 (pEB3) transformant. The molecular weight was estimated to be 39 kDa by SDS-PAGE. Zymogram analysis confirmed that the purified protein is agarolytic and TLC analysis revealed that the predominant end-products of agar hydrolysis are neoagarohexaose and neoagarobiose, which indicates the same mode of action as that observed for the agarase produced extracellularly by Pseudoalteromonas sp. LS2i.

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Klein, Géraldine. "Nouvelles molécules naturelles inhibitrices du développement de biofilms de bactéries marines." Brest, 2011. http://www.theses.fr/2011BRES2038.

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Dès qu’une surface est immergée dans un fluide, elle peut être colonisée par des microorganismes et être recouverte d’un biofilm. La formation des biofilms est une préoccupation majeure en médecine, mais aussi en agroalimentaire et dans le secteur industriel car pouvant engendrer des pertes économiques. La description et la purification de nouvelles molécules visant à prévenir ou à éradiquer la formation de biofilm est donc d’un intérêt majeur. Deux souches bactériennes, Pseudoalteromonas sp. 3J6 et Pseudoalteromonas sp. D41, ont montré un effet inhibiteur du développement de biofilms d’autres bactéries. Le travail effectué a consisté dans un premier temps à optimiser la production des molécules inhibitrices, et à décrire leur spectre d’action et leurs effets. Puis, dans un second temps, nous avons partiellement purifié ces molécules. Pour quantifier rapidement l’activité antibiofilm des molécules produites dans les surnageants de culture de 3J6 et D41 sur un grand nombre d’échantillons, nous avons développé un test en microplaque 96 puits. Ce test est adapté pour des études de l’adhésion bactérienne et de la croissance des biofilms. Nous avons ainsi pu démontrer que les conditions de culture optimales pour la production de molécules inhibitrices par 3i6 et D41 étaient les suivantes respectivement 24 et 12 h de culture en VNSS à 25°C. Nous avons démontré que ces molécules antibiofilm présentaient un large spectre d’action inhibant la formation de biofilm par 13 des 19 souches différentes testées. De plus, nous avons pu constater que les spectres d’action de 3J6 et D41 ne sont pas identiques pour 4 des souches sensibles, suggérant la production de molécules différentes. L’originalité de ces dernières réside dans leur action ciblée sur le mode de vie en biofilm. En effet, les molécules des surnageants de 3J6 et D41 n’ont aucun effet bactéricide sur les bactéries planctoniques, tandis qu’elles limitent la biomasse et l’épaisseur des et/ou diminue la viabilité des bactéries les constituant. Cependant, seules les molécules produites par D41 ont une action inhibitrice sur l’adhésion des bactéries à la surface. La purification des molécules inhibitrices, en partie de nature protéique, a été conduite à partir des surnageants bruts. Ces molécules ayant montré des propriétés différentes, deux stratégies ont été mises en place. Une chromatographie en phase inverse C18 sur le surnageant de 3i6 nous a permis d’associer l’activité inhibitrice à des molécules de poids moléculaire inférieur à 10 kDa, potentiellement des peptides. Sur le surnageant de D41, une combinaison de chromatographie échangeuse d’anions suivie d’une chromatographie en filtration sur gel ont été utilisées pour purifier plusieurs protéines d’environ 100 kDa
As soon as a surface area is immersed in a fluid, it can be colonised by microorganisms and then be covered by a biofilm. The biofilms formation is a major preoccupation in medicine, as well as in the food industry as it could lead to substantial economic fosses. The description and purification of new molecules, preventing or inhibing the formation of biofilms are, therefore, of major interest. Two bacterial strains, Pseudoalteromonas sp. 3J6 and Pseudoalteromonas sp. D41 have been shown to have an inhibitory effect on the development of biofilms from other bacteria. The study involved, firstly, optimizing the production of inhibitory molecules and describing their scope of action and their effects. Secondly, these molecules were partially purified. In order to screen and evaluate the anti-biofilm activity of molecules produced in 3J6 and D41 culture supernatants on a large number of bacteria and samples, a 96-well microtiter-plate test was set up. This bioassay was adapted and optimized for bacterial adhesion and biofilm growth studies. We demonstrated that the optimal culture conditions for the production of inhibitory molecules by 3J6 and D41 were the following: 24h and 12h of culture in VNSS medium at 25°C respectively. We also showed that these anti-biofilm molecules have a wide range of activities, inhibiting the formation of biofilm in 13 out of the 19 different strains under study. Moreover, we also noted that the activity spectra of 3i6 and D41 are not identical in 4 of the sensitive strains, suggesting that different molecules may have been produced. In fact, the 3J6 and D41 supernatant molecules do not have any bactericidal effects on planktonic bacteria, but they reduce the biomass and the thickness of biofilms and / or restrict the viability of their constituent bacteria. However, only the molecules produced by D41 have an inhibitory effect on surface of adhesive bacteria. The purification of inhibitory molecules, partly from protein origin, was carried out using crude supernatants. As these molecules displayed different properties, two different techniques were employed. By using reversed phase chromatography C18, it was possible to associate the inhibitory activity with molecules of less than 10 kDa in molecular weight, primarily peptides. By combining anion-exchange chromatography and gel-filtration chromatography, several proteins of around 100 kDa molecular mass were purified

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31

Nordmark, Eva-Lisa. "Structural and Interaction Studies of Bacterial Polysaccharides by NMR Spectroscopy." Doctoral thesis, Stockholm : Institutionen för organisk kemi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-284.

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Andersson, Pontus, Selma Edenståhl, Elin Eriksson, Tora Hävermark, Jonas Nielsen, and Alma Pihlblad. "Framtidens expressionssystem för svåruttryckta proteiner : Utvärdering av tolv expressionssystem." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352114.

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Today, recombinant expression of proteins is used for a variety of purposes. One of these is the production of allergens, which are vital components in allergy diagnostics. However, traditional expression systems such as Escherichia coli and Pichia pastoris might not have the capacity to express all proteins of interest. Thermo Fisher, which is a leading producer of allergy tests, has requested an evaluation of different microorganisms and their capacity for heterologous protein expression in order to expand their existing toolbox of expression systems. This summary was made through a literature study, where twelve organisms were evaluated. Six eukaryotic and six prokaryotic expression systems are compared based on their ability to properly glycosylate protein, need for specific culture conditions, safety, protease activity, duration, protein yield and protein solubility. The prokaryotic systems – Corynebacterium glutamicum , Lactococcus lactis , Pseudomonas fluorescens , Pseudoalteromonas haloplanktis , Ralstonia eutropha and Streptomyces lividans – are characterized by being easy to cultivate, operating in different temperature ranges and providing relatively high yields of recombinant protein. The eukaryotic systems – Aspergillus fungi, the green algae Chlamydomonas reinhardtii , the yeast Hansenula polymorpha , the parasite Leishmania tarentolae , the moss Physcomitrella patens and suspension-based plant cells – all have very different morphology and properties. In comparison with the prokaryotic systems, it can be concluded that they are generally better at folding and providing the correct glycosylation patterns for mammalian and plant proteins. However, they require more time and effort to establish a competent cell line. Furthermore, the resulting protein yield is usually less than for the prokaryotic systems. The conclusion can be drawn that no expression system is perfect. The solution is a toolbox, containing various expression systems and vector systems, providing the basis for successful expression of all kinds of complex proteins. Based on the evaluation of expression systems in this review, such toolbox can be obtained.

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Higgins, Brian Patrick. "Regulation of IS492 transposition in Pseudoalteromonas atlantica." 2006. http://purl.galileo.usg.edu/uga%5Fetd/higgins%5Fbrian%5Fp%5F200608%5Fphd.

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Albino, Antonella. "The glutathione biosynthesis in the psychrophile Pseudoalteromonas haloplanktis." Tesi di dottorato, 2011. http://www.fedoa.unina.it/8856/1/Albino_Antonella_24.pdf.

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Reduced glutathione (GSH), together with its oxidized form (GSSG), is the most effective antioxidant system responsible for controlling the cellular redox state. Its biosynthesis from glutamate, cysteine and glycine, normally requires two enzymes. Indeed, γ-glutamyl-cysteine ligase (GshA) forms γ-glutamyl-cysteine, whereas glutathione synthetase (GshB) leads to the formation of GSH. In the genome of Pseudoalteromonas haloplanktis, a psychrophilic eubacterium isolated from Antarctic sea water, two genes coding for GshA (PhGshA-I and PhGshA-II ) and one gene for GshB (PhGshB) were putatively identified. The study of the biochemical properties of these enzymes was addressed with an appropriate heterologous expression system, thus leading to the production of the recombinant forms of PhGshB and PhGshA-II (rPhGshB and rPhGshA-II), purified by affinity chromatography. The first enzyme investigated was rPhGshB. Its purification was achieved either in the absence or in the presence of β-mercaptoethanol. The study of its molecular properties showed that, when purified in the presence of β-mercaptoethanol, rPhGshB underwent a covalent modification; however, this modification did not significantly affect its biochemical properties. The molecular mass of rPhGshB in denaturing conditions was 36 kDa, corresponding to the mass of the PhGshB monomer; in non denaturing conditions the mass determined by gel-filtration ranged between 74 and 136 kDa, respectively, values corresponding to a dimeric or tetrameric organization. The different behavior depended on the enzyme concentration and the data suggested that at higher concentrations the enzyme formed an unstable tetramer that at lower concentrations was converted into a dimeric and more stable form. To study the activity of rPhGshB, a new method for direct determination was developed, based on the hydrolysis of the radioactive substrate [γ32P] ATP; in fact, the synthesis of GSH catalyzed by GshB is coupled to the hydrolysis of ATP. The ATPase activity of rPhGshB required the presence of the other two substrates, glycine and γ-glutamylcysteine (γ-Glu-Cys). rPhGshB showed its maximum activity in the 7.4-8.2 pH range. The enzyme activity required also the presence of a divalent cation and at 5 mM Mg++ reached its maximum. The kinetic parameters of rPhGshB at 15°C, the optimum value for growth of P. haloplanktis, were determined. The enzyme showed a comparable affinity for ATP and γ-Glu-Cys (Km = 0.26 mM and 0.25 mM, respectively), whereas a lower affinity was determined for glycine (Km = 0.75 mM). The comparison of these data with those of the corresponding enzyme from other sources showed the remarkable similarity with Escherichia coli; a similar lower affinity for glycine compared to the other two substrates was found in the other sources. Enzyme inhibition studies showed that GSSG is an inhibitor of rPhGshB. The effect of temperature on the kinetic parameters of rPhGshB was analysed in the temperature range 10-30°C. The data showed that rPhGshB is already active at 10°C and its Vmax significantly increased with temperature up to 25°C; on the other hand, in the temperature interval considered, a minimum variation of Km was observed. The kcat values were then used to draw an Arrhenius plot and in the range of linearity (10-25°C) an activation energy of 75 kJ/mol was determined, a value quite high for a psychrophilic enzyme. The thermostability of rPhGshB was analyzed using a thermal inactivation profile and an extrapolated half-life of 10 min at 50.5°C was derived. This value was slightly high for a psychrophilic enzyme, although not unusual for enzymes involved in the control of the cellular redox state. A value of 208 kJ/mol was calculated for the energy of activation of the heat inactivation process; this value was intermediate between those usually obtained for psychrophilic and mesophilic enzymes, respectively. Finally, the development of a new crystallization technique allowed the obtainment of crystal forms of rPhGshB, useful for the determination of the three-dimensional structure of the enzyme by X-ray diffraction. The biochemical characterization of rPhGshA-II was started, using the same assay adopted for rPhGshB. Preliminary data obtained showed that the enzyme activity of rPhGshA-II requires a reducing agent in the reaction mixture; furthermore, the presence of the other two substrates glutamate and cysteine, is also required. The activity of rPhGshA-II needed a higher concentration of Mg++ (10-20 mM) compared to that already determined for rPhGshB. When the characterization of the molecular and biochemical properties of PhGshA-II will be completed, it will be possible to reconstitute in vitro for the first time the system for the biosynthesis of glutathione in a psychrophilic organism.

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Hettle, John Andrew. "Carrageenan desulfation and depolymerization by the marine isolate Pseudoalteromonas sp. PS47." Thesis, 2018. https://dspace.library.uvic.ca//handle/1828/10458.

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Carrageenans are sulfated polysaccharides found in the cell walls of red algae with 20 – 30 % of the dry weight coming from sulfate esters. The understanding of how heterotrophic bacteria desulfate and depolymerize carrageenan has become a rather arduous endeavor as there are 15 different classes of carrageenan distinguished by the degree of sulfation and the presence or absence of a unique galactose derivative, the 3,6-anhydro-D-galactose. The depolymerization of carrageenan requires the removal of the sulfate substituents, a role fulfilled by sulfatases, which hydrolyze sulfate esters playing a key role in the regulation of sulfation states that determine the function of sulfated biomolecules. Through structural, mechanistic, and sequence-based studies a highly conserved sulfate-binding motif has been identified among sulfatases; however, the molecular determinants for substrate specificity remain largely speculative. Additionally, the largest sulfatase family S1, requires a unique catalytic residue resulting from a post-translationally modified cysteine in order to be functional thus making them difficult to study in vitro. Using a strain of Pseudoalteromonas sp. PS47 isolated in the Boraston Lab I show that the depolymerization of carrageenan is dependent on the degree of sulfation and that recognition of the leaving group is the driving force behind S1 specificity. With little information on the recognition of sulfated biomolecules, the X-ray crystal structures of the three sulfatases from PS47; PsS1_19A, PsS1_19B, and PsS1_NC in complex with their biological substrates provides a deeper understanding of how carbohydrate specific sulfatases recognize their cognate substrate and how this recognition of the leaving group can be extended to other S1 sulfatase families. Furthermore, I show that an exo-acting glycoside hydrolase (PsGH42) requires desulfation of carrageenan oligosaccharides before it can hydrolyze the β-glycosidic linkage, a new specificity of family 42. This research demonstrates how carrageenan depolymerization is entirely dependent on the functionality and specificity of the sulfatases found within the carrageenan utilization locus.
Graduate
2019-12-07

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"Integrated -omic study of deep-sea microbial community and new Pseudoalteromonas isolate." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.21027.

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abstract: This thesis research focuses on phylogenetic and functional studies of microbial communities in deep-sea water, an untapped reservoir of high metabolic and genetic diversity of microorganisms. The presence of photosynthetic cyanobacteria and diatoms is an interesting and unexpected discovery during a 16S ribosomal rRNA-based community structure analyses for microbial communities in the deep-sea water of the Pacific Ocean. Both RT-PCR and qRT-PCR approaches were employed to detect expression of the genes involved in photosynthesis of photoautotrophic organisms. Positive results were obtained and further proved the functional activity of these detected photosynthetic microbes in the deep-sea. Metagenomic and metatranscriptomic data was obtained, integrated, and analyzed from deep-sea microbial communities, including both prokaryotes and eukaryotes, from four different deep-sea sites ranging from the mesopelagic to the pelagic ocean. The RNA/DNA ratio was employed as an index to show the strength of metabolic activity of deep-sea microbes. These taxonomic and functional analyses of deep-sea microbial communities revealed a `defensive' life style of microbial communities living in the deep-sea water. Pseudoalteromonas sp.WG07 was subjected to transcriptomic analysis by application of RNA-Seq technology through the transcriptomic annotation using the genomes of closely related surface-water strain Pseudoalteromonas haloplanktis TAC125 and sediment strain Pseudoalteromonas sp. SM9913. The transcriptome survey and related functional analysis of WG07 revealed unique features different from TAC125 and SM9913 and provided clues as to how it adapted to its environmental niche. Also, a comparative transcriptomic analysis of WG07 revealed transcriptome changes between its exponential and stationary growing phases.
Dissertation/Thesis
Ph.D. Civil and Environmental Engineering 2013

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Ruggiero, Immacolata. "Caratterizzazione funzionale e molecolare del fattore di allungamento G da Pseudoalteromonas haloplanktis." Tesi di dottorato, 2008. http://www.fedoa.unina.it/1696/1/Ruggiero_Biochimica.pdf.

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Cotugno, Roberta. "Proprietà molecolari e funzionali del sistema della tioredossina nell'eubatterio psicrofilo Pseudoalteromonas haloplanktis." Tesi di dottorato, 2009. http://www.fedoa.unina.it/3106/1/Cotugno_Roberta_Tesi_A1b.pdf.

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Egan, Suhelen. "Production and regulation of fouling inhibitory compounds by the marine bacterium Pseudoalteromonas tunicata /." 2001. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20010925.141640/index.html.

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Sousa, Joaquim Miguel Gonçalves de. "Exploring the potential of microbes for modulating aquaculture bacterioplankton." Master's thesis, 2021. http://hdl.handle.net/10773/30823.

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The microbial community of recirculating aquaculture systems (RAS) is essential for the maintenance of water quality and disease management. Microbiome modulation, through the promotion of higher diversity and an increase in antagonistic microorganisms, can render an aquaculture system more resilient against disease. In line with this concept, this work aimed to 1) isolate and characterize fungi from the rearing water and biofilter of a fish RAS for potential application as microbiome modulators in the aquaculture sector and 2) assess the potential modulating effects of heat-killed biomass of Pseudoalteromonas spp. (HKP) on RAS bacterioplankton communities. In the first chapter, our microbial isolation efforts resulted in 18 fungal isolates all belonging to the Ascomycota and Basidiomycota phyla, with Pseudotaeniolina globosa being the most prevalent (11/18 isolates). In addition, three of the isolates were identified as Vishniacozyma carnescens. Other organisms found include the Ascomycota species Candida labiduridarum and the Basidiomycota species Dioszegia hungarica, Tilletiopsis lilacina, and Cystobasidium slooffiae. These species may produce secondary metabolites with biotechnological potential, such as antimicrobial and antifungal compounds, and carotenoids, and further research is needed to explore their valorisation in the aquaculture sector. In the second chapter of this thesis, the evaluation of the modulating effects of HKP showed that the strain HKP-SubTr2 had the greatest potential for RAS bacterioplankton modulation. The addition of HKP-SubTr2 (assumed to produce prodigiosin pigments, with possible antagonistic activity) to the rearing water was shown to have a clear modulating effect on aquaculture bacterioplankton communities. HKP-SubTr2 treatment significantly enriched the relative abundance of orders Bacteriovoracales, Chitinophagales, and Oceanospirillales in comparison with untreated control and treatment with unpigmented bacteria Escherichia coli HK-DH5α. In addition, the treatment significantly lowered the relative abundance of Rhodobacterales. No significant differences were found among the tested water quality parameters between the different treatments and the control. These findings indicated that the use of heat-killed microbial biomass may be an interesting strategy for aquaculture bacterioplankton modulation. However, further studies are necessary to investigate its potential effect on fish health and water quality during aquaculture production.
A comunidade microbiana de aquaculturas com sistema de recirculação (RAS) é essencial para a manutenção da qualidade da água e para a prevenção de doenças. A modulação do microbioma, através da promoção de uma elevada diversidade e de um aumento de microrganismos antagonistas, pode tornar um sistema de aquacultura mais resiliente contra o aparecimento de doenças. Tendo isto em conta, este trabalho procurou 1) isolar e caracterizar fungos da água e biofiltros de RAS para potencial aplicação como moduladores do microbioma em aquacultura e 2) avaliar o potencial de biomassa inativada por calor de Pseudoalteromonas spp. (HKP) na modulação da comunidade do bacterioplâncton de RAS. No primeiro capítulo, os esforços de isolamento resultaram em 18 isolados de fungos pertencentes aos filos Ascomycota e Basidiomycota, sendo Pseudotaeniolina globosa o mais prevalente (11/18 isolados). Para além disso, três dos isolados foram identificados como Vishniacozyma carnescens. Outros isolados incluem a espécie de Ascomycota Candida labiduridarum e as espécies de Basidiomycota Dioszegia hungarica, Tilletiopsis lilacina e Cystobasidium slooffiae. Estas espécies podem produzir metabolitos secundários com potencial interesse biotecnológico, nomeadamente compostos antimicrobianos, e carotenoides, pelo que serão estudadas em trabalhos futuros, de modo a explorar a sua valorização no setor da aquacultura. No segundo capítulo desta tese, a avaliação do efeito de HKP demonstrou que a estirpe HKP-SubTr2 tem o maior potencial para a modulação do bacterioplâncton de RAS. A adição de HKP-SubTr2 (potencial produtora do pigmento prodigiosina, com atividade antagonista) à água teve um claro efeito modulador nas comunidades do bacterioplâncton. Este tratamento enriqueceu significativamente a abundância relativa de Bacteriovoracales, Chitinophagales e Oceanospirillales em comparação com o controlo não tratado e com o tratamento com Escherichia coli DH5α, uma bactéria não pigmentada. Para além disso, o tratamento com HKP-SubTr2 diminuiu significativamente a abundância relativa de Rhodobacterales. Não houve quaisquer diferenças significativas nos parâmetros de qualidade testados entre os diferentes tratamentos e o controlo. Estes resultados indicam que o uso de biomassa inativada por calor poderá ser uma estratégia interessante para a modulação do bacterioplâncton de aquacultura. No entanto, são ainda necessários mais estudos, de modo a avaliar o seu potencial efeito na saúde dos peixes e na qualidade da água nos sistemas de aquacultura.
Mestrado em Microbiologia

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Ventura, Francisco Duarte da Cunha. "Characterization of gene or gene clusters responsible for the production of antimicrobial compounds in Pseudoalteromonas atlantica." Master's thesis, 2014. http://hdl.handle.net/1822/34057.

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Dissertação de mestrado integrado em Biomedical Engineering
The intensive and unconscious use of antibiotics alongside with the decrease of investment in research of novel molecules (since the mid 1960s), has led to a rise of highly resistant bacteria. These microorganisms have been developing mechanisms that enable them to survive to the aggressions of classical antibiotics. Also, these self-defense mechanisms are easily transmitted between bacteria, which is a worrisome panorama. It is necessary to get back to a proactive fight against these microorganisms. Living organisms have long proven to be a rich source for antimicrobial compounds due to their need to fight for their place in ecological niches. The marine environment is known to be prolific with microbial communities and thus a great diversity of bioactive compounds was already discovered. In this thesis work, I searched for novel antimicrobial compounds in a marine bacteria, Pseudoalteromonas atlantica. A genome mining approach was followed. A search for clusters coding for secondary metabolites with antimicrobial characteristics was done using softwares such as AntiSmash, ClustScan, HHpred or BLASTx. This process resulted in the finding of 17 putative clusters coding for polyketide synthase and also 1 putative cluster coding for a bacteriocin. To assess if P. atlantica is, in fact, capable of producing antimicrobial compounds, and in the positive case, to further enhance the production of such compounds, a compound production optimization procedure was performed. Optimal culture conditions for production of antibiotic compounds in P. atlantica were met for Marine Broth culture medium at a temperature of 23ºC, a pH of 8 and a 120 rpm agitation. Bacteria-free spent media proved to inhibit the growth of Escherichia coli K12. Moreover, a bacteria-free spent media from cultures grown in the presence of a competitor (E. coli K12; Staphylococcus aureus; Pseudomonas aeruginosa or Vibrio harveyi) has also resulted in the inhibition of Salmonella enteritidis. These results indicate that the P. atlantica genome might be a source for novel antimicrobial compounds. In fact, under the described conditions, P. atlantica was capable of producing antimicrobial molecules with a narrow activity spectrum.
O uso intensivo e inconsciente de antibióticos e a quebra do investimento na investigação de novas moléculas (desde meados dos ano 60), levou ao aparecimento de bactérias altamente resistentes. Estes microorganismos têm desenvolvido mecanismos que os permite sobreviver às agressões provocadas pelos antibióticos clássicos. Além disso, estes mecanismos de auto-defesa são facilmente transmitidos entre diferentes espécies de bactérias, o que é um cenário muito preocupante. É então necessário voltar a uma atitude proactiva na luta contra estes microorganismos. Os microorganismos já há muito provaram ser uma fonte rica em compostos antimicrobianos, devido à sua necessidade de lutar por um lugar nos respectivos nichos ecológicos. O ambiente marinho é conhecido por ser fértil em comunidades microbianas e portanto uma grande diversidade de compostos bioactivos foram já descobertos. Nesta tese procurei por compostos antimicrobianos numa bactéria marinha, a Pseudoalteromonas atlantica. Seguiu-se uma estratégia de “genome mining”. Foi realizada uma procura de clusters de metabolitos secundários de cariz antimicrobiano, através do recurso a ferramentas como o AntiSmash, ClustScan, HHpred ou BLASTx. Todo este processo resultou na descoberta de 17 putativos clusters de poliquétidos sintetases e 1 putativo cluster de bacteriocina. De forma a avaliar se a P. atlantica é capaz de produzir compostos antimicrobianos, e, em caso positivo, para aumentar a produção desses compostos, foi realizado um procedimento de optimização da produção do antimicrobiano. As condições óptimas para a produção de compostos antimicrobianos em P. atlantica revelaram ser o uso de meio marinho (Marine Broth), a uma temperatura de 23ºC, um pH de 8 e uma agitação de 120 rpm. O meio de cultura gasto desprovido de bactérias provou inibir o crescimento de Escherichia coli K12. Além disso, na presença de um competidor (E. coli K12; Staphylococcus aureus; Pseudomonas aeruginosa or Vibrio harveyi), o meio de cultura de P. atlantica, também resultou na inibição de Salmonella enteritidis. Estes resultados indicam que o genoma da P. atlantica pode ser uma fonte de compostos antimicrobianos inauditos. De facto, nas condições referidas no presente trabalho, a P. atlantica foi capaz de produzir moléculas antimicrobianas, com um espectro de actividade aparentemente muito específico.

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Ling, Lai Chin, and 黎敬凌. "Pseudoalteromonas haloplanktis, ATCC 14393 fermented with Acrochaetium sp., Sarcodia suiae and Nostoc commune to extract bioactive substances." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7wgbu6.

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碩士
國立臺灣海洋大學
水產養殖學系
107
Algae are rich in protein and other bioactive components. The breakage of macroalgae cells which are a noteworthy prevention for cell interruption and hindering essential extraction of the biomolecules are required for complete arrival of bioactive mixes. Therefore, this study has been aimed to evaluate the extraction efficiency of bioactive constituents such as essential pigments and polysaccharides of three types of algae (Acrochaetium sp., Sarcodia suiae and Nostoc commune) as substrates by fermentation. In stage one experiment, three type of algae (Acrochaetium sp., S. suiae and N. commune) were used as substrates to ferment with Pseudoalteromonas haloplanktis ATCC14393. After crude fragmentation (except Acrochaetium sp.), they were started for fermentation. The concentration of phycobiliproteins, chlorophyll a, reducing sugar and total count of bacteria were measured. Thereafter, the analysis of reducing sugar on three fermented algae were assayed by HPLC analysis. Acrochaetium sp. was carried for further analysis in stage two experiment. Acrochaetium sp., S. suiae and N. commune fermented by using P. haloplanktis ATCC14393 has produced more bioactive constituents such as phycoerythrin, phycocyanin, allophycocyanin and reducing sugar from the beginning until the end of fermentation. Acrochaetium sp. has produced the highest phycoerythrin with more than 0.1 mg·mL-1 compare to S. suiae and N. commune. After a strong fragmentation (stage two experiment), the content of phycoerythrin has increased to 0.206 mg in each gram of Acrochaetium sp. After strong fragmentation, the residue is taken out to the first phase fermentation which produced 0.296 mg of phycoerythrin after six hours of fermentation. It has produced 0.649 g phycoerythrin in each gram of algae around 48 h in the second phase fermentation. This result shows that with the addition of P. haloplanktis, ATCC 14393 in the fermentation process can extract more phycoerythrin as similar to phycocyanin and allophycocyanin. All of the algae after fermentation have produced mannose under undissociated enzyme condition. Acrochaetium sp., N. commune and S. suiae has produced 70.815 g·mL-1, 56.228 g·mL-1, and 50.347 g·mL-1 of mannose respectively. After enzyme dissociation, Acrochaetium sp. and S. suiae have produced mannose and xylose, while N. commune has given out mannose and others unknown sugar.

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Castellano, Immacolata. "Caratterizzazione biochimica della superossido dismutasi dall'eubatterio psicrofilo Pseudoalteromonas haloplanktis: ruolo regolatorio di un residuo di cisteina molto reattivo." Tesi di dottorato, 2007. http://www.fedoa.unina.it/1363/1/Castellano_Biochimica_e_Biologia_Cellulare_e_Molecolare.pdf.

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Li, Yu-Wen, and 李玉雯. "Purification, Cloning, and Characterization of an Amine Oxidoreductase from the Purple Pigmented Marine Bacterium, Pseudoalteromonas sp. MA C1-2." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/08260641077688824642.

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碩士
國立高雄海洋科技大學
海洋生物技術研究所
101
The marine purple pigmented bacterium Pseudoalteromonas sp. MA C1-2 (MA C1-2) isolated from corals has previously been shown to secret two antibacterial metabolites, one having been shown to be the purple pigment, violacein, the other hydrogen peroxide. The current study aimed to identify the source of the hydrogen peroxide. Through a multi-faceted approach involving ammonium sulfate precipitation, anion exchange chromatography, SDS PAGE, and tandem MS analysis, the source of the hydrogen peroxide was narrowed down to be a amine oxidoreductase enzyme. To verify this finding, a strategy combining degenerate PCR and gene walking were employed to obtain a gene encoding the amine oxidoreductase enzyme from MA C1-2 genome, which we named the PAO gene (Pseudoalteromonas amine oxidoreductase). The cell lysate of the BL21(DE3) stain expressing the gene showed strong positive results in the H2O2 indicator plate, while the control bacterial strain gave only negative results. Finally, the purified enzyme was further confirmed to display strong H2O2-generating activity. Together, the results demonstrate that MA C1-2 generates hydrogen peroxide through the activity of the PAO gene, which could be an effective anti-fouling mechanism.

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[Verfasser], Le-Van-Truong. "Characterization of the pectinolytic enzymes of the marine psychrophilic bacterium Pseudoalteromonas haloplanktis strain ANT-505 / vorgelegt von Le Van Truong." 2006. http://d-nb.info/984430180/34.

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Milazzo, Lisa. "How resonance Raman spectroscopy can give valuable insights into diverse aspects of heme protein structure and function." Doctoral thesis, 2019. http://hdl.handle.net/2158/1154362.

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Resonance Raman (RR) spectroscopy complemented by UV-Vis absorption spectroscopy is a very powerful technique to investigate the structure-function relationships of heme proteins, a widely distributed and biological relevant class of proteins which can play different biological functions. Since the protein activity is tightly linked to the structure of the heme active site, my study has been devoted to the investigation of several heme proteins involved in important biological processes, to obtain a comprehensive spectroscopic signature, with the aim to highlight the relationship between the heme pocket architecture and the protein function. The studies were carried out on native proteins and selected site-directed mutants, at both room (298 K) and low (80 K) temperature, at various pH, and in presence of various exogenous ligands, spanning the excitation wavelengths from UV to the visible region.

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