The diploma thesis was focused on evaluation of non-thermal (cold) plasma seed treatment of cabbage (Brassica oleracea var. capitata), on its health and production properties and on the effects against Xanthomonas campestris pv. campestris (Xcc). A soil fungus Trichoderma virens (TVI) was used as additional seed treatment. The field experiment showed that microwave, low pressure, 500 W non-thermal plasma and 4 minute exposure time did not have a significant effect on Xcc, but had a positive influence - in combination with Xcc and TVI - on plants´ vitality and yield. Further, this plasma treatment, in combination with Xcc, had a negative impact on seeds´ germination. Non-thermal plasma treatment with the above-mentioned parameters proved to be unsuitable for cabbage seed treatment.

The work is focused on the observation of the effect of selenium nanoparticles [Se] on seedlings of head cabbage, whose seeds were inoculated with Xanthomonas campestris pv campestris (Pammel) Dowson. The paper summarizes protocols of nanoparticle synthesis using various methods. A special part was devoted to methods of synthesis of selenium [Se] nanoparticles. Methods of conventional synthesis and methods of biological synthesis have been described. When using a preparation containing nanoparticles, the effect on bacteria inoculated on seed was clearly seen. Increasing concentration of the product visibly appeared to be stronger. The use of SelenBact appears to be very promising when applied to seed contaminated with bacteria Xanthomonas campestris pv campestris (Pammel) Dowson.

The objectives of this project were to develop a high performance liquid chromatographic method for separating the pigment esters mixture, to determine the locations of the pigment moiety in the isolated esters using pholosiphases, and to characterize the pigment-protein complex and determine its distribution in other bacteria. Saponification of the two pigment esters 1 and 2 with aqueous KOH yielded two free pigments on TLC plates developed by two solvent systems. The fasters moving of these two free pigments co-chromatographed with the one free pigment produced from each pigment ester by phospholipase A2 treatment. This suggests that the pigment molecule is a methoxy derivative of xanthomonadin and is esterified to the 2-position of the glycerol moiety of each pigment ester. No free pigment was released from phospholipases C and D treatment of the two pigment esters, indicating that pigment is not esterified to the sorbitol or phosphate moiety of pigment esters 1 or 2.

Made available in DSpace on 2014-06-11T19:32:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-20Bitstream added on 2014-06-13T19:03:06Z : No. of bitstreams: 1 seabrajunior_s_dr_botfca.pdf: 725253 bytes, checksum: 63ae443c8f6290ceb25a9148ff0290f4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O brócolis (Brassica oleracea var. italica) é uma espécie exigente em nutrientes, destacando-se os elementos nitrogênio e potássio, que são exigidos em maiores quantidades pelas plantas, podendo influenciar na produção, qualidade e também na severidade de diversas doenças. Com o objetivo de estudar os efeitos desses elementos na severidade da podridão negra, causado por Xanthomonas campestris pv. Campestri (Xcc) e a sua influência na produção de brócolis tipo inflorescência única, foi realizado o experimento no Departamento de Produção Vegetal/Horticultura da FCA/UNESP - Botucatu. O delineamento utilizado foi em parcela subdividida com fatorial na subparcela, em blocos casualisados com quatro repetições. Na parcela avaliou-se a influência da inoculação (plantas não inoculadas e inoculadas com Xcc) e na subparcela avaliou-se o fatorial 4 x 4, doses de potássio (0, 275, 550 e 825 kg ha-1) e nitrogênio (0, 150, 300 e 450 kg ha-1). O híbrido de brócolis utilizado foi o BRO68 (Rogers). A semeadura foi realizada em 18/02/2004 e as plântulas foram transplantadas aos 33 dias após semeadura (DAS) em vasos de dez litros, sob ambiente protegido. Realizou-se a inoculação pelo método de palito (64 DAS) e as colheitas foram realizadas de 28/05/2004 a 12/06/2004 (99 aos 114 DAS). As adubações foram realizadas no plantio, pela incorporação ao solo de 45% da dose de potássio e 10% da dose de nitrogênio de cada tratamento e em cobertura, aplicados via fertirrigação (55% do potássio e 90% do nitrogênio). Foram avaliadas a severidade da Xcc através do PANC (porcentagem da altura necrosada do caule) e porcentagem das folhas retidas nas plantas (FR), produção e diâmetro das cabeças, teores de macronutrientes, no momento da inoculação e na colheita... / Broccoli is one vegetable specie that demand fertilizers, mainly nitrogen and potassium are required in higher quantity, which can have influence in yields, quality and severity level of diseases. Evaluated the influence of nitrogen and potassium fertilizations in black rot (Xanthomonas campestris pv. campestris) severity and broccoli yields, in the Departamento de Produção Vegetal/Horticultura - FCA/UNESP - Botucatu country, São Paulo State, Brazil. The experimental design was split plot with factorial in plot, in randomized blocks with four replicants. In the plot was evaluated the influence of inoculation (plant no inoculated or inoculated with Xcc (Xanthomonas campestris v. campestris) with four replications, considering potassium rates (0, 275, 550 and 825 kg ha-1) and nitrogen rates (0, 150, 300 and 450 kg ha-1). Hybrid BRO 68 (Rogers) was seeded in 18/02/2004 and transplanted in 33 days after seeding (DAS) for pot with 10 liters of capacity in plastic house conditions. The Xcc inoculation was made using toothpick methods (64 DAS) and the harvesting occurs in 28/05/2004 to 12/06/2004 (99 to 114 DAS). Incorporated in soil before planting with 45% potassium rate and 10% nitrogen rate of each treatment, and after planting fertilization was in fertirrigation system (55% potassium and 90% nitrogen). The severity of Xcc was evaluated with a PANC (percentage of necrosed height of the stem) method and the percentage of leaf kept in plants, the broccoli yield and the diameter of head, macronutrients ratios, was assessment during inoculations and the harvesting. The results showed that interactions among of three factors did not have significance for neither characteristics, potassium x nitrogen fertilizers interactions was significance to yield, head diameter, and PANC and macronutrients ratios (N, P, K, Ca and Mg)...(Complete abstract click electronic access below)

Submitted in complete fulfillment for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2010. / Xanthomonas campestris pv phaseoli produced an extracellular endoinulinase on various carbon sources. The highest inulinase production of 9.24 ± 0.03 IU ml¯¹by X. campestris pv. phaseoli was attained using an optimized medium comprising of 3% sucrose and 2.5% tryptone. Inulinase production in X. campestris pv. phaseoli was further enhanced through ethylmethanesulfonate mutagenesis. The resulting mutant, X. campestris pv. phaseoli KM 24 demonstrated enhanced inulinase production of 22.09 ± 0.03 IU ml¯¹after 24 h, which was 2.4 – fold higher than that of the wild type. Inulinase production by this mutant was scaled up in a 5 L fermenter yielding a final activity of 21.87 ± 0.03 IU ml¯¹with an inulinase/invertase (I/S) ratio of 2.6 after 18 h. Maximum volumetric (21 865 IU 1¯¹ h¯¹) and specific (119 025 IU g¯¹ h¯¹) productivities of inulinase were attained in a fermenter after 18h growth. Inulin hydrolysis by the crude inulinase and subsequent detection of mono- and oligosaccharides indicated the presence of an endoinulinase. The extracellular endoinulinase from the mutant KM 24 was purified to homogeneity by gel filtration chromatography and had a specific activity of 174.74U/mg. the optimum pH and temperature of the purified enzyme were found to be 6.0 and 50°C, respectively. The enzyme was stable up to 60°C, retaining over 60% activity for 30 min, but activity rapidly declined at temperatures above 60°C. The pure inulinase enzyme was also found to be stable between pH 6-9. The Lineweaver-Burk plots showed that the apparent Km and Vmax values of the inulinase for inulin were 1.15 mg/ml and 15µM/min, respectively. The Kcat value was found to be 0.145 min¯¹ with an enzyme catalytic efficiency of 0.126 mg¯¹.ml.min¯¹.This mutant demonstrated good potential for large scale production of inulinase and fructooligosaccharides. / National Research Foundation

Saccostomus campestris display sexual disparity in the use of summer daily torpor in response to energy stress. The hypothesis that males may compensate for a limited heterothermic capacity with lower normothermic body temperatures by maintaining lower resting metabolic rates relative to females was tested. Furthermore, the influence of testosterone on torpor incidence in males was investigated. Body temperature (T[b]) and oxygen consumption (VO₂) were measured at various ambient temperatures (Tₐ) and were compared between the sexes under food ad libitum and food restriction treatments. There were no significant differences in T[b] and VO₂ between sexes under food ad libitum treatment. Under food restriction there were pronounced sex differences in the employment of heterothermy. Females defended a lower setpoint T[b] for torpor (ca. 25°C), than males (ca. 29°C), and also employed torpor more frequently than males. Non-torpid males did, however show slight reductions in VO₂ under food restriction. The effect of testosterone on daily torpor was investigated by comparing minimum T[b]and torpor frequency of castrated mice implanted with testosterone-filled (experimental) and saline-filled (control) silastic capsules in response to food ad libitum and food restriction treatments. Testosterone inhibited torpor in males. The majority of control animals employed torpor under both food ad libitum and food restriction diets. It was concluded that although the animals were capable of shallow, summer torpor, it was confined to moderate ambient temperatures and was not used at low Tₐ's where several animals became pathologically hypothermic. Females derive energetic benefits from the use of torpor whereas males may partially compensate for their limited heterothennic capacity by a reduction in resting metabolic rates, accompanied by moderate reductions in body temperature during energetically stressful periods. The difference in the capacity for daily heterothenny between sexes was attributed to differences in their reproductive physiology. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.

Made available in DSpace on 2014-08-13T14:50:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-28Bitstream added on 2014-08-13T18:01:03Z : No. of bitstreams: 1 000747755_20150228.pdf: 1109024 bytes, checksum: 06c7c1198100258efa09641d5260b3b6 (MD5) Bitstreams deleted on 2015-03-03T12:45:20Z: 000747755_20150228.pdf,Bitstream added on 2015-03-03T12:45:57Z : No. of bitstreams: 1 000747755.pdf: 3571665 bytes, checksum: f979331ca4c187b62a431c61c0a3ef61 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A bactéria Xanthomonas citri subsp. citri (Xac) é o agente causal do cancro cítrico asiático, uma severa doença que afeta todos os cultivares das principais áreas produtores ao redor do mundo. Até o momento não há nenhum tratamento capaz de combater o cancro cítrico. Dessa forma, a erradicação de plantas infectadas constitui a única medida de controle efetivo para evitar a disseminação da doença. Com o programa de erradicação sob ameaça e um claro risco de que Xac torne-se endêmica na principal área produtora de laranja no mundo, há uma necessidade urgente para o desenvolvimento de novas estratégias para o combate do cancro. Neste trabalho foi avaliada a atividade de galatos de alquila para a prevenção do crescimento de Xac. Estes ésteres desempenham um potencial de atividade anti-Xac similar ao da kanamicina (controle positivo), como observado pelo teste Resazurin Microtiter Assay (REMA). O tratamento de Xac com estas substâncias induziram alteração na morfologia celular, e a investigação de possíveis alvos intracelulares usando linhagens de Xac com o septo e centrômero marcados, apontaram para um alvo comum envolvido com a segregação cromossômica/divisão. Além disso, a inoculação artificial de citros com Xac pré-tratada com galatos de alquila demonstraram que a bactéria perde a habilidade de colonizar o hospedeiro, o que é uma evidência a favor do potencial destes ésteres em proteger plantas contra a infecção de Xac. No intuito de determinar o mecanismo de ação, alguns experimentos foram realizados em Bacillus subtillis. Os galatos de alquila também mostraram-se ativos contra B. subtillis. A localização de FtsZ foi rapidamente perturbada após o tratamento, o que sugere que as substâncias possam ter a maquinaria de divisão celular como alvo. Quando estudados in vitro, as substâncias afetaram FtsZ formando estruturas que podiam ser facilmente sedimentadas em alta velocidade, ... / The bacterium Xanthomonas citri subsp. citri (Xac) is the causal agent of asiatic citrus canker, a severe disease that affects all the cultivars of citrus in the main citrus producing areas worldwide. There is no curative treatment for citrus canker. Thus, the eradication of infected plants constitutes the only effective control for the spread of disease. Since the eradication program is under threat, and with a clear risk of Xac becoming endemic in the main orange producing area worldwide, there is an urgent need for the development of new strategies to fight citrus canker. In this work, were evaluated the potential use of alkyl galates to prevent Xac growth. These esters displayed a potent anti-Xac activity similar to kanamycin (positive control) as observed by the Resazurin Microtiter Assay (REMA). Treatment of Xac with these compounds induced altered cell morphology, and investigation of the possible intracellular targets using Xac strains labeled for septum and centromere pointed to a common target involved with chromosome segregation and cell division. Furthermore, artificial inoculation of citrus with Xac pre-treated with alkyl galates showed that the bacterium loses the ability to colonize its host, which argued in favor of the potential of these esters to protect citrus plants against Xac infection. In attempt to determine their mechanism of action some experiments were performed in Bacillus subtillis. Alkyl gallates were also active against B. subtilis and the FtsZ localization is rapidly perturbed after the treatment, which suggested that the compounds may target the cell division machinery. When studied in vitro, the alkyl gallates affected FtsZ by forming structures that could easily be spun down at high velocity, independent of the presence of nucleotide. These structures seem to be specific since the BSA (bovine serum albumin) protein did not sediment in the presence of the alkyl gallates. Also, GTP hydrolysis, an indicator ... / FAPESP: 10/02667-4 / CNPq: 201196/2012-3

Made available in DSpace on 2014-08-13T14:50:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-28Bitstream added on 2014-08-13T18:01:02Z : No. of bitstreams: 1 000748011_20150228.pdf: 573819 bytes, checksum: 3344da0365a81a0bf0b11e133955fde8 (MD5) Bitstreams deleted on 2015-03-03T12:45:21Z: 000748011_20150228.pdf,Bitstream added on 2015-03-03T12:45:57Z : No. of bitstreams: 1 000748011.pdf: 3605502 bytes, checksum: f4aa4b916761c5c5f0617ddd061382d8 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A bactéria Xanthomonas citri subsp. citri (Xac) é o agente etiológico do cancro cítrico, uma doença severa que afeta plantas de citros em todo o mundo e para a qual não há uma forma eficaz de controle. A obtenção do genoma de Xac sem dúvida representou um marco nos estudos deste microrganismo, porém, muito pouco ainda se sabe sobre alguns de seus processos essenciais como replicação e segregação do material genético, septação, divisão e crescimento celular. A segregação cromossômica é um processo essencial em todas as células vivas. Esse processo envolve uma precisa replicação e particionamento do cromossomo para garantir uma fiel transmissão da informação genética para as células filhas. Esses mecanismos veem sendo extensivamente caracterizados em eucariotos, porém ainda não são muito bem compreendidos em procariotos. Contudo, relatos recentes mostraram que bactérias possuem um sistema tipo mitótico no qual a sequência parS é ligada a ParB e puxada por ParA durante a segregação cromossômica. Nesse trabalho foi identificado e caracterizado um ativo sistema tipo ParAB/parS no fitopatógeno Xac. Várias evidências moleculares e citológicas indicam que ParAB/parS está envolvido no particionamento cromossômico de Xac: i) ParB-GFP localiza-se em um único cluster nas bordas do nucleoide; ii) ParB pode interagir com sequências de ligação parS in vitro e in vivo e realizar spreading lateral, sugerindo a formação de um complexo centromérico ParB/parS; iii) a dinâmica de ParB/parS sugere um modelo assimétrico de segregação cromossômica em Xac; iv) enquanto a super expressão de ParA e ParB não alteram a morfologia celular, mutações em parB acarretam na filamentação celular, formação de células em cadeias e sem nucleoide, prejudicando a segregação cromossômica e/ou divisão celular; v) a localização subcelular de ParBGFP e ZapA-mCherry evidenciam o envolvimento entre segregação ... / The bacterium Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker, a severe disease that affects citrus plants worldwide. An effective control for the citrus canker is not available yet, and the elimination of infected plants continues to be the recommended practice to control the disease. Although the genome sequence of Xac has been available for almost a decade, its biology is not well known and there is a lack in the literature of studies concerning chromosome segregation and cell division of this plant pathogen. Chromosome segregation is an essential process to all living cells. This process involves a precise replication and partitioning of the chromosome in order to obtain a faithful transmission of hereditary information to the daughter cells. These mechanisms have been extensively characterized in eukaryotes but are still not well understood in prokaryotes. However, recent reports have shown that bacteria have a mitotic-like system in which the parS sequence is bound by ParB and pulled by ParA during chromosome segregation. In this work it was identified and characterized an active ParAB/parS system in the Xac plant pathogen. Several molecular and cytological evidence indicate that ParAB/parS is involved in chromosome partitioning in Xac: i) ParB-GFP localizes into a single cluster at the edges of the nucleoid, as shown for other ParB-like factors; ii) ParB can interact with parS binding sites in vitro and in vivo through a nucleation mechanism followed by lateral spreading, suggesting the formation of a ParB/parS centromerelike complex; iii) ParB/parS dymanic suggests an asymmetric model of chromosome segregation; iv) whereas the overexpression of both ParA and ParB does not cause any cell morphology defect, a parB mutation renders cells filamentous and often anucleate, which suggests impaired chromosome segregation and/or cell division; v) ParB-GFP and ZapA-mCherry (marker for the Z-ring) localization ...

Orientador : Henrique Ferreira / Coorientador: Luis Vitor Silva do Sacramento / Banca: José Belasque Junior / Banca: Luis Octávio Regasini / Banca: Fernando Rogério Pavan / Banca: Franklin Behlau / Resumo: A bactéria Xanthomonas citri subsp. citri (Xac) é o agente causal do cancro cítrico asiático, uma severa doença que afeta todos os cultivares das principais áreas produtores ao redor do mundo. Até o momento não há nenhum tratamento capaz de combater o cancro cítrico. Dessa forma, a erradicação de plantas infectadas constitui a única medida de controle efetivo para evitar a disseminação da doença. Com o programa de erradicação sob ameaça e um claro risco de que Xac torne-se endêmica na principal área produtora de laranja no mundo, há uma necessidade urgente para o desenvolvimento de novas estratégias para o combate do cancro. Neste trabalho foi avaliada a atividade de galatos de alquila para a prevenção do crescimento de Xac. Estes ésteres desempenham um potencial de atividade anti-Xac similar ao da kanamicina (controle positivo), como observado pelo teste Resazurin Microtiter Assay (REMA). O tratamento de Xac com estas substâncias induziram alteração na morfologia celular, e a investigação de possíveis alvos intracelulares usando linhagens de Xac com o septo e centrômero marcados, apontaram para um alvo comum envolvido com a segregação cromossômica/divisão. Além disso, a inoculação artificial de citros com Xac pré-tratada com galatos de alquila demonstraram que a bactéria perde a habilidade de colonizar o hospedeiro, o que é uma evidência a favor do potencial destes ésteres em proteger plantas contra a infecção de Xac. No intuito de determinar o mecanismo de ação, alguns experimentos foram realizados em Bacillus subtillis. Os galatos de alquila também mostraram-se ativos contra B. subtillis. A localização de FtsZ foi rapidamente perturbada após o tratamento, o que sugere que as substâncias possam ter a maquinaria de divisão celular como alvo. Quando estudados in vitro, as substâncias afetaram FtsZ formando estruturas que podiam ser facilmente sedimentadas em alta velocidade, ... / Abstract: The bacterium Xanthomonas citri subsp. citri (Xac) is the causal agent of asiatic citrus canker, a severe disease that affects all the cultivars of citrus in the main citrus producing areas worldwide. There is no curative treatment for citrus canker. Thus, the eradication of infected plants constitutes the only effective control for the spread of disease. Since the eradication program is under threat, and with a clear risk of Xac becoming endemic in the main orange producing area worldwide, there is an urgent need for the development of new strategies to fight citrus canker. In this work, were evaluated the potential use of alkyl galates to prevent Xac growth. These esters displayed a potent anti-Xac activity similar to kanamycin (positive control) as observed by the Resazurin Microtiter Assay (REMA). Treatment of Xac with these compounds induced altered cell morphology, and investigation of the possible intracellular targets using Xac strains labeled for septum and centromere pointed to a common target involved with chromosome segregation and cell division. Furthermore, artificial inoculation of citrus with Xac pre-treated with alkyl galates showed that the bacterium loses the ability to colonize its host, which argued in favor of the potential of these esters to protect citrus plants against Xac infection. In attempt to determine their mechanism of action some experiments were performed in Bacillus subtillis. Alkyl gallates were also active against B. subtilis and the FtsZ localization is rapidly perturbed after the treatment, which suggested that the compounds may target the cell division machinery. When studied in vitro, the alkyl gallates affected FtsZ by forming structures that could easily be spun down at high velocity, independent of the presence of nucleotide. These structures seem to be specific since the BSA (bovine serum albumin) protein did not sediment in the presence of the alkyl gallates. Also, GTP hydrolysis, an indicator ... / Doutor

Orientador : Henrique Ferreira / Banca: José Belasque Junior / Banca: Celson Eduardo Benedetti / Banca: Maria Célia Bertolini / Banca: Franklin Behlau / Resumo: A bactéria Xanthomonas citri subsp. citri (Xac) é o agente etiológico do cancro cítrico, uma doença severa que afeta plantas de citros em todo o mundo e para a qual não há uma forma eficaz de controle. A obtenção do genoma de Xac sem dúvida representou um marco nos estudos deste microrganismo, porém, muito pouco ainda se sabe sobre alguns de seus processos essenciais como replicação e segregação do material genético, septação, divisão e crescimento celular. A segregação cromossômica é um processo essencial em todas as células vivas. Esse processo envolve uma precisa replicação e particionamento do cromossomo para garantir uma fiel transmissão da informação genética para as células filhas. Esses mecanismos veem sendo extensivamente caracterizados em eucariotos, porém ainda não são muito bem compreendidos em procariotos. Contudo, relatos recentes mostraram que bactérias possuem um sistema tipo mitótico no qual a sequência parS é ligada a ParB e puxada por ParA durante a segregação cromossômica. Nesse trabalho foi identificado e caracterizado um ativo sistema tipo ParAB/parS no fitopatógeno Xac. Várias evidências moleculares e citológicas indicam que ParAB/parS está envolvido no particionamento cromossômico de Xac: i) ParB-GFP localiza-se em um único cluster nas bordas do nucleoide; ii) ParB pode interagir com sequências de ligação parS in vitro e in vivo e realizar spreading lateral, sugerindo a formação de um complexo centromérico ParB/parS; iii) a dinâmica de ParB/parS sugere um modelo assimétrico de segregação cromossômica em Xac; iv) enquanto a super expressão de ParA e ParB não alteram a morfologia celular, mutações em parB acarretam na filamentação celular, formação de células em cadeias e sem nucleoide, prejudicando a segregação cromossômica e/ou divisão celular; v) a localização subcelular de ParBGFP e ZapA-mCherry evidenciam o envolvimento entre segregação ... / Abstract: The bacterium Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker, a severe disease that affects citrus plants worldwide. An effective control for the citrus canker is not available yet, and the elimination of infected plants continues to be the recommended practice to control the disease. Although the genome sequence of Xac has been available for almost a decade, its biology is not well known and there is a lack in the literature of studies concerning chromosome segregation and cell division of this plant pathogen. Chromosome segregation is an essential process to all living cells. This process involves a precise replication and partitioning of the chromosome in order to obtain a faithful transmission of hereditary information to the daughter cells. These mechanisms have been extensively characterized in eukaryotes but are still not well understood in prokaryotes. However, recent reports have shown that bacteria have a mitotic-like system in which the parS sequence is bound by ParB and pulled by ParA during chromosome segregation. In this work it was identified and characterized an active ParAB/parS system in the Xac plant pathogen. Several molecular and cytological evidence indicate that ParAB/parS is involved in chromosome partitioning in Xac: i) ParB-GFP localizes into a single cluster at the edges of the nucleoid, as shown for other ParB-like factors; ii) ParB can interact with parS binding sites in vitro and in vivo through a nucleation mechanism followed by lateral spreading, suggesting the formation of a ParB/parS centromerelike complex; iii) ParB/parS dymanic suggests an asymmetric model of chromosome segregation; iv) whereas the overexpression of both ParA and ParB does not cause any cell morphology defect, a parB mutation renders cells filamentous and often anucleate, which suggests impaired chromosome segregation and/or cell division; v) ParB-GFP and ZapA-mCherry (marker for the Z-ring) localization ... / Doutor