DSpace Angular :: Browsing by Author "Gonzalez, Bernardo"

Browsing by Author "Gonzalez, Bernardo"

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Altered Gut Microbiota in a Fragile X Syndrome Mouse Model
(2021) Altimiras, Francisco; Garcia, Jose Antonio; Palacios-Garcia, Ismael; Hurley, Michael J.; Deacon, Robert; Gonzalez, Bernardo; Cogram, Patricia
The human gut microbiome is the ecosystem of microorganisms that live in the human digestive system. Several studies have related gut microbiome variants to metabolic, immune and nervous system disorders. Fragile X syndrome (FXS) is a neurodevelopmental disorder considered the most common cause of inherited intellectual disability and the leading monogenetic cause of autism. The role of the gut microbiome in FXS remains largely unexplored. Here, we report the results of a gut microbiome analysis using a FXS mouse model and 16S ribosomal RNA gene sequencing. We identified alterations in the fmr1 KO2 gut microbiome associated with different bacterial species, including those in the genera Akkermansia, Sutterella, Allobaculum, Bifidobacterium, Odoribacter, Turicibacter, Flexispira, Bacteroides, and Oscillospira. Several gut bacterial metabolic pathways were significantly altered in fmr1 KO2 mice, including menaquinone degradation, catechol degradation, vitamin B6 biosynthesis, fatty acid biosynthesis, and nucleotide metabolism. Several of these metabolic pathways, including catechol degradation, nucleotide metabolism and fatty acid biosynthesis, were previously reported to be altered in children and adults with autism. The present study reports a potential association of the gut microbiome with FXS, thereby opening new possibilities for exploring reliable treatments and non-invasive biomarkers.
An Engineered Device for Indoleacetic Acid Production under Quorum Sensing Signals Enables Cupriavidus pinatubonensis JMP134 To Stimulate Plant Growth
(2018) Zuniga, Ana; de la Fuente, Francisco; Federici, Fernán; Lionne, Corinne; Bonnet, Jerome; de Lorenzo, Victor; Gonzalez, Bernardo
Aromatic compounds degradation plays a role in colonization of Arabidopsis thaliana and Acacia caven by Cupriavidus pinatubonensis JMP134
(2012) Ledger, Thomas; Zuniga, Ana; Kraiser, Tatiana; Dasencich, Paola; Donoso, Raul; Perez-Pantoja, Danilo; Gonzalez, Bernardo
Plant rhizosphere and internal tissues may constitute a relevant habitat for soil bacteria displaying high catabolic versatility towards xenobiotic aromatic compounds. Root exudates contain various molecules that are structurally related to aromatic xenobiotics and have been shown to stimulate bacterial degradation of aromatic pollutants in the rhizosphere. The ability to degrade specific aromatic components of root exudates could thus provide versatile catabolic bacteria with an advantage for rhizosphere colonization and growth. In this work, Cupriavidus pinatubonensis JMP134, a well-known aromatic compound degrader (including the herbicide 2,4-dichlorophenoxyacetate, 2,4-D), was shown to stably colonize Arabidopsis thaliana and Acacia caven plants both at the rhizoplane and endorhizosphere levels and to use root exudates as a sole carbon and energy source. No deleterious effects were detected on these colonized plants. When a toxic concentration of 2,4-D was applied to colonized A. caven, a marked resistance was induced in the plant, showing that strain JMP134 was both metabolically active and potentially beneficial to its host. The role for the beta-ketoadipate aromatic degradation pathway during plant root colonization by C. pinatubonensis JMP134 was investigated by gene inactivation. A C. pinatubonensis mutant derivative strain displayed a reduced ability to catabolise root exudates isolated from either plant host. In this mutant strain, a lower competence in the rhizosphere of A. caven was also shown, both in gnotobiotic in vitro cultures and in plant/soil microcosms.
Bioaugmentation with Pseudomonas sp strain MHP41 promotes simazine attenuation and bacterial community changes in agricultural soils
(2010) Morgante, Veronica; Lopez-Lopez, Arantxa; Flores, Cecilia; Gonzalez, Myriam; Gonzalez, Bernardo; Vasquez, Monica; Rossello-Mora, Ramon; Seeger, Michael
Bioremediation is an important technology for the removal of persistent organic pollutants from the environment. Bioaugmentation with the encapsulated Pseudomonas sp. strain MHP41 of agricultural soils contaminated with the herbicide simazine was studied. The experiments were performed in microcosm trials using two soils: soil that had never been previously exposed to s-triazines (NS) and soil that had > 20 years of s-triazine application (AS). The efficiency of the bioremediation process was assessed by monitoring simazine removal by HPLC. The simazine-degrading microbiota was estimated using an indicator for respiration combined with most-probable-number enumeration. The soil bacterial community structures and the effect of bioaugmentation on these communities were determined using 16S RNA gene clone libraries and FISH analysis. Bioaugmentation with MHP41 cells enhanced simazine degradation and increased the number of simazine-degrading microorganisms in the two soils. In highly contaminated NS soil, bioaugmentation with strain MHP41 was essential for simazine removal. Comparative analysis of 16S rRNA gene clone libraries from NS and AS soils revealed high bacterial diversity. Bioaugmentation with strain MHP41 promoted soil bacterial community shifts. FISH analysis revealed that bioaugmentation increased the relative abundances of two phylogenetic groups (Acidobacteria and Planctomycetes) in both soils. Although members of the Archaea were metabolically active in these soils, their relative abundance was not altered by bioaugmentation.
CHANGES IN BACTERIAL COMMUNITY STRUCTURE ASSOCIATED WITH COASTAL COPPER ENRICHMENT
(SOC ENVIRONMENTAL TOXICOLOGY & CHEMISTRY-SETAC, 2008) Moran, Ana C.; Hengst, Martha B.; De la Iglesia, Rodrigo; Andrade, Santiago; Correa, Juan A.; Gonzalez, Bernardo
Marine bacterial communities isolated from the water column, sediment, the rock surface, and the green seaweed Ulva compressa were studied in an intertidal ecosystem. The study area included a coastal zone chronically affected by copper mine waste disposals. Bacterial community composition was analyzed by terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA genes, and multivariate analyses of T-RFLP data sets were used for comparisons. Results showed that diversity and richness indexes were not able to detect differences among compartments. However, comparisons within the same compartment clearly showed that copper enrichment was associated with changes in the composition of the bacterial communities and revealed that the magnitude of the effect depends on the compartment being considered. In this context, communities from sediments appeared as the most affected by copper enrichment. The present study also demonstrated that intertidal bacterial communities were dominated by Gammaproteobacteria, Firmicutes, and Actinobacteria and the changes in these communities were mainly due to changes in their relative abundances.
Diversity of the marine picocyanobacteria Prochlorococcus and Synechococcus assessed by terminal restriction fragment length polymorphisms of 16S-23S rRNA internal transcribed spacer sequences
(2008) Lavin, Paris; Gomez, Patricia; Gonzalez, Bernardo; Ulloa, Osvaldo
In order to assess the appropriateness of the use of internal transcribed spacer (ITS) sequences for the study of population genetics of marine cyanobacteria, we amplified and cloned the 16S rRNA gene plus the 16S-23S ITS regions of six strains of Prochlorococcus and Synechococcus. We analyzed them by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphisms (T-RFLP). When using the standard application of these techniques, We obtained more than one band or terminal restriction fragment (T-RF) per strain or cloned sequence. Reports in literature have Suggested that these anomalies can result from the formation of secondary structures. Secondary structures of the ITS sequences of Prochlorococcus and Synechococcus strains were computationally modelled at the different temperatures that were used during the polymerase chain reaction (PCR). Modelling results predicted the existence of hairpin loops that would still be present at the extension temperature; it is likely that these loops produced incomplete and single stranded PCR products. We modified the standard T-RFLP procedure by adding the labelled ITS primer in the last two cycles of the PCR reaction: this resulted, in most cases, in only one T-RF per ribotype. Application of this technique to a natural picoplankton community in marine waters off northern Chile, showed that it was possible to identify the presence, and determine the relative abundance, of several phylogenetic lineages within the genera Prochlorococcus and Synechococcus inhabiting the euphotic zone. Phylogenetic analysis of ITS sequences obtained by cloning and sequencing DNA from the same sample confirmed the presence of the different genotypes. With the proposed modification, T-RFLP profiles should therefore be Suitable for studying the diversity of natural populations of cyanobacteria, and should become an important tool to study the factors influencing the genetic Structure and distribution of these organisms.
Early successional patterns of bacterial communities in soil microcosms reveal changes in bacterial community composition and network architecture, depending on the successional condition
(2017) Rodriguez-Valdecantos, Gustavo; Manzano, Marlene; Sanchez, Raimundo; Urbina, Felipe; Hengst, Martha B.; Antonio Lardies, Marco; Ruz, Gonzalo A.; Gonzalez, Bernardo
Soil ecosystem dynamics are influenced by the composition of bacterial communities and environmental conditions. A common approach to study bacterial successional dynamics is to survey the trajectories and patterns that follow bacterial community assemblages; however early successional stages have received little attention. To elucidate how soil type and chemical amendments influence both the trajectories that follow early compositional changes and the architecture of the community bacterial networks in soil bacterial succession, a time series experiment of soil microcosm experiments was performed. Soil bacterial communities were initially perturbed by dilution and subsequently subjected to three amendments: application of the pesticide 2,4-dichlorophenoxyacetic acid, as a pesticide-amended succession; application of cycloheximide, an inhibitor affecting primarily eukaryotic microorganisms, as a eukaryotic-inhibition bacterial succession; or application of sterile water as a non-perturbed control. Terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA gene isolated from soil microcosms was used to generate bacterial relative abundance datasets. Bray-Curtis similarity and beta diversity partition-based methods were applied to identify the trajectories that follow changes in bacterial community composition. Results demonstrated that bacterial communities exposed to these three conditions rapidly differentiated from the starting point (less than 12 h), followed different compositional change trajectories depending on the treatment, and quickly converged to a state similar to the initial community (48-72 h). Network inference analysis was applied using a generalized Lotka-Volterra model to provide an overview of bacterial OTU interactions and to follow the changes in bacterial community networks. This analysis revealed that antagonistic interactions increased when eukaryotes were inhibited, whereas cooperative interactions increased under pesticide influence. Moreover, central OTUs from soil bacterial community networks were also persistent OTUs, thus confirming the existence of a core bacterial community and that these same OTUs could plastically interact according to the perturbation type to quickly stabilize bacterial communities undergoing succession.
Genuine genetic redundancy in maleylacetate-reductase-encoding genes involved in degradation of haloaromatic compounds by Cupriavidus necator JMP134
(2009) Perez-Pantoja, Danilo; Donoso, Raul A.; Sanchez, Miguel A.; Gonzalez, Bernardo
Maleylacetate reductases; (MAR) are required for biodegradation of several substituted aromatic compounds. To date, the functionality of two MAR-encoding genes (tfdF(I) and tfdF(II)) has been reported in Cupriavidus necator JMP134(pJP4), a known degrader of aromatic compounds. These two genes are located in tfd gene clusters involved in the turnover of 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3-CB). The C. necator JMP134 genome comprises at least three other genes that putatively encode MAR (tcpD, hqoD and hxqD), but confirmation of their functionality and their role in the catabolism of haloaromatic compounds has not been assessed. RT-PCR expression analyses of C. necator JMP134 cells exposed to 2,4-D, 3-CB, 2,4,6-trichlorophenol (2,4,6-TCP) or 4-fluorobenzoate (4-FB) showed that tfdF(I) and tfdF(II) are induced by haloaromatics channelled to halocatechols as intermediates. In contrast, 2,4,6-TCP only induces tcpD, and any haloaromatic compounds tested did not induce hxqD and hqoD. However, the tcpD, hxqD and hqoD gene products showed MAR activity in cell extracts and provided the MAR function for 2,4-D catabolism when heterologously expressed in MAR-lacking strains. Growth tests for mutants of the five MAR-encoding genes in strain JMP134 showed that none of these genes is essential for degradation of the tested compounds. However, the role of tfdF(I)/tfdF(II) and tcpD genes in the expression of MAR activity during catabolism of 2,4-D and 2,4,6-TCP, respectively, was confirmed by enzyme activity tests in mutants. These results reveal a striking example of genetic redundancy in the degradation of aromatic compounds.
Hydroquinone and H₂O₂ differentially affect the ultrastructure and expression of ligninolytic genes in the basidiomycete Ceriporiopsis subvermispora
(2009) Amoroso, Alejandro; Mancilla, Rodrigo A.; Gonzalez, Bernardo; Vicuna, Rafael
The biodegradation of lignin is a highly oxidative process in which various oxidases and peroxidases play a major role. During lignin decay, the generation of aromatic compounds and reactive oxygen species leads to oxidative stress. In this work, the effect of the oxidative compounds H2O2 and hydroquinone in the ligninolytic fungus Ceriporiopsis subvermispora was studied, both at the ultrastructural and at the transcriptional level. Transmission electron microscopy revealed the presence of microvesicles and extensive cytoplasm degeneration after incubation with hydroquinone, but not with H2O2. Studies of the intracellular redox state of the fungus showed that hydroquinone causes a transient decrease in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and an increase in the glutathione-S-transferase mRNA levels. These results suggest that hydroquinone produces oxidative stress in this microorganism. On the other hand, it was observed that hydroquinone, but not H2O2, affects Mn-dependent peroxide and laccase transcripts levels. We propose that the mechanism by which the fungus reacts against oxidative stress contributes to its selectivity toward lignin during wood decay.
Involvement of several transcriptional regulators in the differential expression of tfd genes in Cupriavidus necator JMP134
(2009) Trefault, Nicole; Guzman, Leda; Perez, Heidi; Godoy, Margarita; Gonzalez, Bernardo
Cupriavidus necator JMP134 has been extensively studied because of its ability to degrade chloroaromatic compounds, including the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 3-chlorobenzoic acid (3-CB), which is achieved through the pJP4-encoded chlorocatechol degradation gene clusters: tfdC(I)D(I)E(I)F(I), and tfdD(II)C(II)E(II)F(II). The present work describes a different tfd-genes expression profile depending on whether C. necator cells were induced with 2,4-D or 3-CB. By contrast, in vitro binding assays of the Purified transcriptional activator TfdR showed similar binding to both tfd intergenic regions; these results were confirmed by in Vivo Studies of the expression of transcriptional lacZ fusions for these intergenic regions. Experiments aimed at investigating whether other pJP4 plasmid or chromosomal regulatory proteins could contribute to the differences in the response of both tfd promoters to induction by 2,4-D and 3-CB showed that the transcriptional regulators from the benzoate degradation pathway, CatR I and CatR2, affected 3-CB- and 2,4-D-related growth capabilities. It was also determined that the ISJP4-interrupted protein TfdT decreased growth on 3-CB. In addition, an ORF with 34% amino acid identity to IcIR-type transcriptional regulator members and located near the tfd(II) gene cluster module was shown to modulate the 2,4-D growth capability. Taken together, these results Suggest that tfd transcriptional regulation in C. necator JMP134 is far more complex than previously thought and that it involves proteins from different transcriptional regulator families. [Int Microbiol 2009; 12(2):97-106]
Novel lineages of Prochlorococcus thrive within the oxygen minimum zone of the eastern tropical South Pacific
(2010) Lavin, Paris; Gonzalez, Bernardo; Francisco Santibanez, J.; Scanlan, David J.; Ulloa, Osvaldo
P>The eastern tropical Pacific Ocean holds two of the main oceanic oxygen minimum zones of the global ocean. The presence of an oxygen-depleted layer at intermediate depths, which also impinges on the seafloor and in some cases the euphotic zone, plays a significant role in structuring both pelagic and benthic communities, and also in the vertical partitioning of microbial assemblages. Here, we assessed the genetic diversity and distribution of natural populations of the cyanobacteria Prochlorococcus and Synechococcus within oxic and suboxic waters of the eastern tropical Pacific using cloning and sequencing, and terminal restriction fragment length polymorphism (T-RFLP) analyses applied to the 16S-23S rRNA internal transcribed spacer region. With the T-RFLP approach we could discriminate 19 cyanobacterial clades, of which 18 were present in the study region. Synechococcus was more abundant in the surface oxic waters of the eastern South Pacific, while Prochlorococcus dominated the subsurface low-oxygen waters. Two of the dominant clades in the oxygen-deficient waters belong to novel and yet uncultivated lineages of low-light adapted Prochlorococcus.
Role of eukaryotic microbiota in soil survival and catabolic performance of the 2,4-D herbicide degrading bacteria Cupriavidus necator JMP134
(2007) Manzano, Marlene; Moran, Ana C.; Tesser, Bruno; Gonzalez, Bernardo
Cupriavidus necator ( formerly Ralstonia eutropha) JMP134, harbouring the catabolic plasmid pJP4, is the best-studied 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide degrading bacterium. A study of the survival and catabolic performance of strain JMP134 in agricultural soil microcosms exposed to high levels of 2,4-D was carried out. When C. necator JMP134 was introduced into soil microcosms, the rate of 2,4- D removal increased only slightly. This correlated with the poor survival of the strain, as judged by 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) profiles, and the semi-quantitative detection of the pJP4-borne tfdA gene sequence, encoding the first step in 2,4- D degradation. After 3 days of incubation in irradiated soil microcosms, the survival of strain JMP134 dramatically improved and the herbicide was completely removed. The introduction of strain JMP134 into native soil microcosms did not produce detectable changes in the structure of the bacterial community, as judged by 16S rRNA gene T-RFLP profiles, but provoked a transient increase of signals putatively corresponding to protozoa, as indicated by 18S rRNA gene T-RFLP profiling. Accordingly, a ciliate able to feed on C. necator JMP134 could be isolated after soil enrichment. In native soil microcosms, C. necator JMP134 survived better than Escherichia coli DH5 alpha (pJP4) and similarly to Pseudomonas putida KT2442 ( pJP4), indicating that species specific factors control the survival of strains harbouring pJP4. The addition of cycloheximide to soil microcosms strongly improved survival of these three strains, indicating that the eukaryotic microbiota has a strong negative effect in bioaugmentation with catabolic bacteria.
Strict and direct transcriptional repression of the pobA gene by benzoate avoids 4-hydroxybenzoate degradation in the pollutant degrader bacterium Cupriavidus necator JMP134
(2011) Donoso, Raul A.; Perez-Pantoja, Danilo; Gonzalez, Bernardo
As other environmental bacteria, Cupriavidus necator JMP134 uses benzoate as preferred substrate in mixtures with 4-hydroxybenzoate, strongly inhibiting its degradation. The mechanism underlying this hierarchical use was studied. A C. necator benA mutant, defective in the first step of benzoate degradation, is unable to metabolize 4-hydroxybenzoate when benzoate is also included in the medium, indicating that this substrate and not one of its catabolic intermediates is directly triggering repression. Reverse transcription polymerase chain reaction analysis revealed that 4-hydroxybenzoate 3-hydroxylase-encoding pobA transcripts are nearly absent in presence of benzoate and a fusion of pobA promoter to lacZ reporter confirmed that benzoate drastically decreases the transcription of this gene. Expression of pobA driven by a heterologous promoter in C. necator benA mutant, allows growth on 4-hydroxybenzoate in presence of benzoate, overcoming its repressive effect. In contrast with other bacteria, regulators of benzoate catabolism do not participate in repression of 4-hydroxybenzoate degradation. Moreover, the effect of benzoate on pobA promoter can be observed in heterologous strains with the sole presence of PobR, the transcriptional activator of pobA gene, indicating that PobR is enough to fully reproduce the phenomenon. This novel mechanism for benzoate repression is probably mediated by direct action of benzoate over PobR.
The Complete Multipartite Genome Sequence of Cupriavidus necator JMP134, a Versatile Pollutant Degrader
(2010) Lykidis, Athanasios; Perez-Pantoja, Danilo; Ledger, Thomas; Mavromatis, Kostantinos; Anderson, Iain J.; Ivanova, Natalia N.; Hooper, Sean D.; Lapidus, Alla; Lucas, Susan; Gonzalez, Bernardo; Kyrpides, Nikos C.
Background: Cupriavidus necator JMP134 is a Gram-negative beta-proteobacterium able to grow on a variety of aromatic and chloroaromatic compounds as its sole carbon and energy source.
The microbial community from the early-plant colonizer (Baccharis linearis) is required for plant establishment on copper mine tailings
(NATURE RESEARCH, 2021) Consuelo Gazitua, Maria; Morgante, Veronica; Josefina Poupin, Maria; Ledger, Thomas; Rodriguez Valdecantos, Gustavo; Herrera, Catalina; Del Carmen Gonzalez Chavez, Maria; Ginocchio, Rosanna; Gonzalez, Bernardo
Plants must deal with harsh environmental conditions when colonizing abandoned copper mine tailings. We hypothesized that the presence of a native microbial community can improve the colonization of the pioneer plant, Baccharis linearis, in soils from copper mining tailings. Plant growth and microbial community compositions and dynamics were determined in cultivation pots containing material from two abandoned copper mining tailings (Huana and Tambillos) and compared with pots containing fresh tailings or surrounding agricultural soil. Controls without plants or using irradiated microbe-free substrates, were also performed. Results indicated that bacteria (Actinobacteria, Gammaproteobacteria, and Firmicutes groups) and fungi (Glomus genus) are associated with B. linearis and may support plant acclimation, since growth parameters decreased in both irradiated (transiently without microbial community) and fresh tailing substrates (with a significantly different microbial community). Consistently, the composition of the bacterial community from abandoned copper mining tailings was more impacted by plant establishment than by differences in the physicochemical properties of the substrates. Bacteria located at B. linearis rhizoplane were clearly the most distinct bacterial community compared with those of fresh tailings, surrounding soil and non-rhizosphere abandoned tailings substrates. Beta diversity analyses showed that the rhizoplane bacterial community changed mainly through species replacement (turnover) than species loss (nestedness). In contrast, location/geographical conditions were more relevant than interaction with the plants, to explain fungal community differences.
Tobacco Smoke Mediated Induction of Sinonasal Microbial Biofilms
(PUBLIC LIBRARY SCIENCE, 2011) Goldstein Daruech, Natalia; Cope, Emily K.; Zhao, Ke Qing; Vukovic, Katarina; Kofonow, Jennifer M.; Doghramji, Laurel; Gonzalez, Bernardo; Chiu, Alexander G.; Kennedy, David W.; Palmer, James N.; Leid, Jeffery G.; Kreindler, James L.; Cohen, Noam A.
Cigarette smokers and those exposed to second hand smoke are more susceptible to life threatening infection than nonsmokers. While much is known about the devastating effect tobacco exposure has on the human body, less is known about the effect of tobacco smoke on the commensal and commonly found pathogenic bacteria of the human respiratory tract, or human respiratory tract microbiome. Chronic rhinosinusitis (CRS) is a common medical complaint, affecting 16% of the US population with an estimated aggregated cost of $6 billion annually. Epidemiologic studies demonstrate a correlation between tobacco smoke exposure and rhinosinusitis. Although a common cause of CRS has not been defined, bacterial presence within the nasal and paranasal sinuses is assumed to be contributory. Here we demonstrate that repetitive tobacco smoke exposure induces biofilm formation in a diverse set of bacteria isolated from the sinonasal cavities of patients with CRS. Additionally, bacteria isolated from patients with tobacco smoke exposure demonstrate robust in vitro biofilm formation when challenged with tobacco smoke compared to those isolated from smoke naive patients. Lastly, bacteria from smoke exposed patients can revert to a non-biofilm phenotype when grown in the absence of tobacco smoke. These observations support the hypothesis that tobacco exposure induces sinonasal biofilm formation, thereby contributing to the conversion of a transient and medically treatable infection to a persistent and therapeutically recalcitrant condition.

Browsing by Author "Gonzalez, Bernardo"

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