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The maintenance of viable and stable Xanthomonascells is crucial for the xanthan reliable research and industrial production. The method, storage and recovery conditions should preserve bothviability and phenotypical and genotypical features. Here, the effectiveness classical methods on the long-term preservation of different Xanthomonas arboricola pathovar pruni strains was to determine.Strains were preserved by monthly sub-culturing in solid medium and lyophilization. After 12 years the viability of the strains, was assessed, as well as their productive capacity and the viscosity of the xanthan gum produced by these strains kept by lyophilization and sub-culturing. Among the lyophilized strains, only those stored at -18 °C were viable after 12 years. The productive capacity of the strains were poorly affected by lyophilization, the passage of the cultures into a solid nutrition medium being sufficient for them to return to their normal metabolism. The viscosity of the synthesized xanthan gum was method-dependent and higher for the lyophilized strains. The work and its findings arenew and original because a work on this topic has never been published before. The results obtained allow the breaking of paradigms regarding the preservation of Xanthomonas.(AU)

A manutenção de células de Xanthomonas viáveis e estáveis é crucial para se obter uma pesquisa confiável e para a produção de xantana industrial.O método, o armazenamento eascondições de recuperação devem preservar tanto a viabilidade quanto as características fenotípicas e genotípicas. O objetivo do estudo foi determinar a eficácia dos métodos clássicos na preservação a longo prazo de diferentes cepas de Xanthomonas arboricolapatovarpruni. As cepas foram preservadas por subcultivo mensal em meio sólido e liofilização. Após 12 anos,avaliou-se a viabilidade das linhagens, bem como a capacidade produtiva e a viscosidade da goma xantana produzida por essas linhagens mantidas por liofilização e subcultivo. Entre as cepas liofilizadas, somente foram viáveis, após 12 anos, as armazenadas a -18°C. A capacidade produtiva das cepas foi pouco afetada pela liofilização, sendo suficiente a passagem das culturas para um meio de cultivosólido para que elas voltassem ao seu metabolismo normal. A viscosidade da goma xantana sintetizada foi dependente do método e maior para as cepas liofilizadas. O estudo e suas descobertas sãonovos e originais porque um trabalho sobre este tópico nunca foi publicado antes. Os resultados obtidos permitem quebrar paradigmas quanto à preservação de Xanthomonas.(AU)

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The efficiency of alternative preservation techniques for Xanthomonas arboricola pv pruni was studied. The preservation methods in sunflower seeds, glass beads and sterile soil were suitable for maintaining viability and productive capacity of xanthan pruni.

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Poly(3-hydroxybutyrate) (P(3HB)) is a biodegradable plastic biopolymer that accumulates as lipophilic inclusions in the cytoplasm of some microorganisms. The biotechnological process by which P(3HB) is synthesized occurs in two phases. The first phase involves cell growth in a complex culture medium, while the second phase involves polymer accumulation in the presence of excess carbon sources. As such, the efficiency of the second phase depends on the first phase. The aim of this study was to evaluate culture media with different concentrations of sucrose and glucose and different pH values in the inoculum phase of Ralstonia solanacearum RS with the intention of identifying methods by which the biomass yield could be increased, subsequently enhancing the yield of P(3HB). The culture medium was formulated according to the experimental planning type of central composite rotational design 22. The independent variables were pH and sugar concentration (sucrose and glucose), and the dependent variables were OD600nm, dry cell weight (DCW), and P(3HB) yield. The highest cell growth, estimated by the OD600nm (20.6) and DCW (5.35) values, was obtained when sucrose was used in the culture medium at a concentration above 35 g.L-1 in combination with an acidic pH. High polymer (45%) accumulation was also achieved under these conditions. Using glucose, the best results for OD600nm (12.5) and DCW (2.74) were also obtained at acidic pH but with a sugar concentration at the minimum values evaluated. Due to the significant accumulation of polymer in the cells that were still in the growth phase, the accumulating microorganism P(3HB) Ralstonia solanacearum RS can be classified as having type II metabolism in relation to the polymer accumulation phase, which is different from other Ralstonia spp. studied until this time.

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The successful production of new, safe, and effective vaccines that generate immunological memory is directly related to adjuvant feature, which is responsible for increasing and/or modulating the immune response. Several compounds display adjuvant activity, including carbohydrates. These compounds play important roles in the immune response, as well as having biocompatible properties in vaccine formulations. One such carbohydrate is xanthan gum, a polysaccharide that is produced by the plant-pathogenic bacterium Xanthomonas spp., which has adjuvant attributes. This study evaluated the immune response induced by xanthan gum associated with ovalbumin in BALB/c mice, which were subcutaneously immunized, in terms of antibody production (IgG1, IgG2a, IgG2b, and IgG3), and assessed the levels of IFN-γ in the splenocyte culture using indirect ELISA. Furthermore, we investigated in vitro cytotoxicity of xanthan in the embryo fibroblasts cell line of the NIH/3T3 mouse by MTT assay and propidium iodide uptake assay. The mice immunized with ovalbumin plus xanthan gum exhibited higher antibody IgG1 responses than control groups. Furthermore, the xanthan polysaccharide was capable of increasing the immunogenicity of antigens by producing IFN-γ and did not exhibit cytotoxicity effects in NIH/3T3 mouse fibroblast cells, considered a promising candidate for vaccine adjuvant.

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Abstract The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress.

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The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress.

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The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. (AU)

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The aim of this work was to evaluate the utilization of analysis of the distribution of relaxation time (DRT) using a dynamic light back-scattering technique as alternative method for the determination of the concentration regimes in aqueous solutions of biopolymers (xanthan, clairana and tara gums) by an analysis of the overlap (c*) and aggregation (c**) concentrations. The diffusion coefficients were obtained over a range of concentrations for each biopolymer using two methods. The first method analysed the behaviour of the diffusion coefficient as a function of the concentration of the gum solution. This method is based on the analysis of the diffusion coefficient versus the concentration curve. Using the slope of the curves, it was possible to determine the c* and c** for xanthan and tara gum. However, it was not possible to determine the concentration regimes for clairana using this method. The second method was based on an analysis of the DRTs, which showed different numbers of relaxation modes. It was observed that the concentrations at which the number of modes changed corresponded to the c* and c**. Thus, the DRT technique provided an alternative method for the determination of the critical concentrations of biopolymers.

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The objective of this study was to identify species of rhizobia (from the IPA 403 and IPA 49 isolates), to assess the physico-chemical characteristics of the biopolymers produced by these rhizobia and to determine the soluble intracellular proteins that are present in these rhizobia. The polysaccharides containing acetyl and pyruvic acid groups that were produced by different strains that had been cultivated in yeast extract mannitol (YEM) medium for 132, 144, and 168 h were evaluated for yield, viscosity, and concentration. Based on the analysis of their partial 16S rDNA sequences, both isolates were identified as Rhizobium tropici. The polymers produced in liquid YEM medium were recovered, dried and weighed to determine culture yield. Soluble intracellular proteins were identified through the techniques of 2D-PAGE and mass spectrometry for cultures that were cultivated for 168 h. The largest biopolymer yield and the highest viscosity and concentration of acetyl and pyruvic acids were obtained from the IPA 403 isolate after 168 h of culture. The proteins that were identified for the CIAT 899 isolate included elongation factor TU, a chaperone; GroE/GroEs and a putative glycosyltransferase, all of which catalyze the production of polysaccharides. For the IPA 403 strain, dinitrogenase and nitrogenase iron proteins were found. In the IPA 49 strain, glyceraldehyde-3-phosphate dehydrogenase was found along with two other proteins, the beta subunit of an electron-transferring flavoprotein and a dehydrogenase.

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The phytopathogenic bacterium Xanthomonas arboricola pv. pruni is the causal agent of Prunus Bacterial Spot disease that infects cultivated Prunus species and their hybrids. Furthermore, X. arboricola pv. pruni (Xap) plays a role in biotechnology since it produces xanthan gum, an important biopolymer used mainly in the food, oil, and cosmetics industry. To gain first insights into the genome composition of this pathovar, genomic DNA of X. arboricola pv. pruni strains was compared to the genomes of reference strains X. campestris pv. campestris B100 (Xcc B100) and X. campestris pv. vesicatoria 85-10 (Xcv 85-10) applying microarray-based comparative genomic hybridizations (CGH). The results implied that X. arboricola pv. pruni 109 lacks 6.67% and 5.21% of the genes present in the reference strains Xcc B100 and Xcv 85-10, respectively. Most of the missing genes were found to be organized in clusters and do not belong to the core genome of the two reference strains. Often they encode mobile genetic elements. Furthermore, the absence of gene clusters coding for the lipopolysaccharide (LPS) O-antigens of Xcc B100 and Xcv 85-10 indicates that the structure of the O-antigen of X. arboricola pv. pruni 109 differs from that of Xcc B100 and Xcv 85-10.

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Amplified fragment length polymorphism (AFLP) was used to analyze the genetic diversity of 14 strains of Xanthomonas arboricola pv. pruni and seven strains of X. axonopodis pv. phaseoli, which are used in xanthan production studies. Relationships identified by the AFLP profiles were assessed for xanthan production capacity, geographical location and host plant. Strains were isolated from 10 different geographic regions in South and Southeast States in Brazil. Data were analyzed for genetic similarity using the Dice coefficient and subjected to UPGMA cluster analysis. A total of 128 AFLP fragments were generated from four primer combinations: EcoRI+C/MseI+0, EcoRI+A/MseI+0, EcoRI+G/MseI+T and EcoRI+G/MseI+A. Of these, 96.1 percent were polymorphic. X. axonopodis pv. phaseoli (S D = 0.27) was shown to be more polymorphic than X. arboricola pv. pruni (S D = 0.58). All 14 pathovar pruni strains were included in a single main group (S D = 0.58), while the pathovar phaseoli strains were divided into three separate groups, with one group containing five strains (S D = 0.38) and two isolated groups (S D = 0.31 and 0.27) composed of only one strain each. Species were distinguished by three and eight specific AFLP markers present in the pathovar phaseoli and the pathovar pruni, respectively. For the unique strain without xanthan production capacity (X. axonopodis pv. phaseoli str. 48), nine specific AFLP bands were found. There was no evidence that geographic area or host plant influenced genetic heterogeneity. Correlations between AFLP patterns and xanthan production capacity were found in some strains, but were not consistent enough to establish a relationship.

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Amplified fragment length polymorphism (AFLP) was used to analyze the genetic diversity of 14 strains of Xanthomonas arboricola pv. pruni and seven strains of X. axonopodis pv. phaseoli, which are used in xanthan production studies. Relationships identified by the AFLP profiles were assessed for xanthan production capacity, geographical location and host plant. Strains were isolated from 10 different geographic regions in South and Southeast States in Brazil. Data were analyzed for genetic similarity using the Dice coefficient and subjected to UPGMA cluster analysis. A total of 128 AFLP fragments were generated from four primer combinations: EcoRI+C/MseI+0, EcoRI+A/MseI+0, EcoRI+G/MseI+T and EcoRI+G/MseI+A. Of these, 96.1% were polymorphic. X. axonopodis pv. phaseoli (SD = 0.27) was shown to be more polymorphic than X. arboricola pv. pruni (SD = 0.58). All 14 pathovar pruni strains were included in a single main group (SD = 0.58), while the pathovar phaseoli strains were divided into three separate groups, with one group containing five strains (SD = 0.38) and two isolated groups (SD = 0.31 and 0.27) composed of only one strain each. Species were distinguished by three and eight specific AFLP markers present in the pathovar phaseoli and the pathovar pruni, respectively. For the unique strain without xanthan production capacity (X. axonopodis pv. phaseoli str. 48), nine specific AFLP bands were found. There was no evidence that geographic area or host plant influenced genetic heterogeneity. Correlations between AFLP patterns and xanthan production capacity were found in some strains, but were not consistent enough to establish a relationship.

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Amplified fragment length polymorphism (AFLP) was used to analyze the genetic diversity of 14 strains of Xanthomonas arboricola pv. pruni and seven strains of X. axonopodis pv. phaseoli, which are used in xanthan production studies. Relationships identified by the AFLP profiles were assessed for xanthan production capacity, geographical location and host plant. Strains were isolated from 10 different geographic regions in South and Southeast States in Brazil. Data were analyzed for genetic similarity using the Dice coefficient and subjected to UPGMA cluster analysis. A total of 128 AFLP fragments were generated from four primer combinations: EcoRI+C/MseI+0, EcoRI+A/MseI+0, EcoRI+G/MseI+T and EcoRI+G/MseI+A. Of these, 96.1% were polymorphic. X. axonopodis pv. phaseoli (S D = 0.27) was shown to be more polymorphic than X. arboricola pv. pruni (S D = 0.58). All 14 pathovar pruni strains were included in a single main group (S D = 0.58), while the pathovar phaseoli strains were divided into three separate groups, with one group containing five strains (S D = 0.38) and two isolated groups (S D = 0.31 and 0.27) composed of only one strain each. Species were distinguished by three and eight specific AFLP markers present in the pathovar phaseoli and the pathovar pruni, respectively. For the unique strain without xanthan production capacity (X. axonopodis pv. phaseoli str. 48), nine specific AFLP bands were found. There was no evidence that geographic area or host plant influenced genetic heterogeneity. Correlations between AFLP patterns and xanthan production capacity were found in some strains, but were not consistent enough to establish a relationship.

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Vacinação tem sido uma prática comum para prevenir ou minimizar os sintomas de doenças causadas por agentes infecciosos. Vacinas têm sido desenvolvidas utilizando-se microrganismos atenuados ou inativados. Recentemente peptídeos sintéticos e proteínas recombinantes constituem a base da nova geração de vacinas. Entretanto, ainda há necessidade de associação destes antíg¬enos a adjuvantes para potencializar seu efeito imunológico. Embora várias substâncias tenham sido avaliadas para sua utilização em vacinas de uso veterinário, a produção de vacinas continua atrelada à utilização dos sais de alumínio ou de emulsões oleosas. O polissacarídeo produzido pela bactéria Xanthomonas sp. é uma nova alternativa para utilização como adjuvante vacinal. O objetivo deste estudo foi avaliar a ação adjuvante da Xantana na resposta humoral de camundongos a uma vacina de herpes suíno tipo 1 (SuHV-1). Os animais foram divididos em cinco grupos, utilizando adjuvantes diferentes para cada grupo. Os títulos de anticorpos foram determinados por ELISA, utilizando como antígeno a respectiva cepa vacinal. O adjuvante à base de Xantana apresentou a maior soroconversão dentre os adjuvantes todos adjuvantes testados. Este efeito foi mais pro¬nunciado quando a via subcutânea foi utilizada. Baseado nos resultados obtidos, conclui-se que o polissacarídeo produzido pela bactéria Xanthomonas sp. possui ação adjuvante superior ou igual aos adjuvantes utilizados em vacinas comerciais

Vaccination has been a common practice to prevent or minimize the symptoms of diseases caused by infectious agents. Vaccines have been developed using an attenuated or inactivated microorganisms. Recently, synthetic peptides and recombinant proteins form the basis of the new generation of vaccines. However, there is need the association of these antigens wich adjuvants to increase its immunological effect. Although several substances have been evaluated for use in vaccines for veterinary use the production of vaccine remains tied to the use of aluminum salts or oily emulsions. The polysaccharide produced by the bacterium Xanthomonas sp. is a new alternative for use as an adjuvant vaccine. This study aimed to evaluate the effect of adjuvant xanthan in humoral response of mice to a vaccine for pig herpes type 1 (SuHV-1). The animals were divided into five groups, using different adjuvants for each group. The titles of antibodies were determined by ELISA, using as antigen the vaccine strain. The adjuvant-based xanthan had the highest seroconversion among all tested adjuvants. This effect was more pronounced when subcutaneous via was used. Based on the results, we conclude that the adjuvant action of the polysaccharide produced by the bacterium Xanthomonas sp. has greater than or equal to the adjuvant used in commercial vaccines

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Vacinação tem sido uma prática comum para prevenir ou minimizar os sintomas de doenças causadas por agentes infecciosos. Vacinas têm sido desenvolvidas utilizando-se microrganismos atenuados ou inativados. Recentemente peptídeos sintéticos e proteínas recombinantes constituem a base da nova geração de vacinas. Entretanto, ainda há necessidade de associação destes antíg¬enos a adjuvantes para potencializar seu efeito imunológico. Embora várias substâncias tenham sido avaliadas para sua utilização em vacinas de uso veterinário, a produção de vacinas continua atrelada à utilização dos sais de alumínio ou de emulsões oleosas. O polissacarídeo produzido pela bactéria Xanthomonas sp. é uma nova alternativa para utilização como adjuvante vacinal. O objetivo deste estudo foi avaliar a ação adjuvante da Xantana na resposta humoral de camundongos a uma vacina de herpes suíno tipo 1 (SuHV-1). Os animais foram divididos em cinco grupos, utilizando adjuvantes diferentes para cada grupo. Os títulos de anticorpos foram determinados por ELISA, utilizando como antígeno a respectiva cepa vacinal. O adjuvante à base de Xantana apresentou a maior soroconversão dentre os adjuvantes todos adjuvantes testados. Este efeito foi mais pro¬nunciado quando a via subcutânea foi utilizada. Baseado nos resultados obtidos, conclui-se que o polissacarídeo produzido pela bactéria Xanthomonas sp. possui ação adjuvante superior ou igual aos adjuvantes utilizados em vacinas comerciais(AU)

Vaccination has been a common practice to prevent or minimize the symptoms of diseases caused by infectious agents. Vaccines have been developed using an attenuated or inactivated microorganisms. Recently, synthetic peptides and recombinant proteins form the basis of the new generation of vaccines. However, there is need the association of these antigens wich adjuvants to increase its immunological effect. Although several substances have been evaluated for use in vaccines for veterinary use the production of vaccine remains tied to the use of aluminum salts or oily emulsions. The polysaccharide produced by the bacterium Xanthomonas sp. is a new alternative for use as an adjuvant vaccine. This study aimed to evaluate the effect of adjuvant xanthan in humoral response of mice to a vaccine for pig herpes type 1 (SuHV-1). The animals were divided into five groups, using different adjuvants for each group. The titles of antibodies were determined by ELISA, using as antigen the vaccine strain. The adjuvant-based xanthan had the highest seroconversion among all tested adjuvants. This effect was more pronounced when subcutaneous via was used. Based on the results, we conclude that the adjuvant action of the polysaccharide produced by the bacterium Xanthomonas sp. has greater than or equal to the adjuvant used in commercial vaccines(AU)

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Goma xantana é um polissacarídeo extracelular produzido pelas bactérias do gênero Xanthomonas. Sua funcionalidade é uma conseqüência direta de sua estrutura química. Esta estrutura tem sido amplamente estudada por ser passível de mudanças, sendo dependente do microrganismo produtor e das condições operacionais aplicadas durante a fermentação. O trabalho tem como objetivo revisar a influência das condições operacionais de produção de xantana nas características físico-químicas da goma produzida.

Xanthan gum is an extracelullar polysaccharide produced by bacteria of the genus Xanthomonas. Itsfunctionality is a direct consequence of its chemical structure. This structure has been widely studiedbecause it is subject to changes, dependant on the producer microrganism and on the operationalconditions applied during the fermentation. The purpose of this paper is to review the influence ofthe operational conditions of xanthan production in the physiochemical characteristics of the gum produceb.

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