Publications by authors named "Leonardo Pavez"

16 Publications

  • Page 1 of 1

Tomato Cultivars With Variable Tolerances to Water Deficit Differentially Modulate the Composition and Interaction Patterns of Their Rhizosphere Microbial Communities.

Front Plant Sci 2021 13;12:688533. Epub 2021 Jul 13.

Laboratorio de Genómica y Genética de Interacciones Biológicas (LG2IB), Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile.

Since drought is the leading environmental factor limiting crop productivity, and plants have a significant impact in defining the assembly of plant-specific microbial communities associated with roots, we aimed to determine the effect of thoroughly selected water deficit tolerant and susceptible cultivars on their rhizosphere microbiome and compared their response with plant-free soil microbial communities. We identified a total of 4,248 bacterial and 276 fungal different operational taxonomic units (OTUs) in soils by massive sequencing. We observed that tomato cultivars significantly affected the alpha and beta diversity of their bacterial rhizosphere communities but not their fungal communities compared with bulk soils (BSs), showing a plant effect exclusively on the bacterial soil community. Also, an increase in alpha diversity in response to water deficit of both bacteria and fungi was observed in the susceptible rhizosphere (SRz) but not in the tolerant rhizosphere (TRz) cultivar, implying a buffering effect of the tolerant cultivar on its rhizosphere microbial communities. Even though water deficit did not affect the microbial diversity of the tolerant cultivar, the interaction network analysis revealed that the TRz microbiota displayed the smallest and least complex soil network in response to water deficit with the least number of connected components, nodes, and edges. This reduction of the TRz network also correlated with a more efficient community, reflected in increased cooperation within kingdoms. Furthermore, we identified some specific bacteria and fungi in the TRz in response to water deficit, which, given that they belong to taxa with known beneficial characteristics for plants, could be contributing to the tolerant phenotype, highlighting the metabolic bidirectionality of the holobiont system. Future assays involving characterization of root exudates and exchange of rhizospheres between drought-tolerant and susceptible cultivars could determine the effect of specific metabolites on the microbiome community and may elucidate their functional contribution to the tolerance of plants to water deficit.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2021.688533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313812PMC
July 2021

Intestinal Transcriptome Analysis Reveals Enrichment of Genes Associated with Immune and Lipid Mechanisms, Favoring Soybean Meal Tolerance in High-Growth Zebrafish ().

Genes (Basel) 2021 05 8;12(5). Epub 2021 May 8.

Núcleo de Investigaciones Aplicadas en Ciencias Veterinarias y Agronómicas, Universidad de Las Américas, Avenida Manuel Montt 948, Santiago 7500975, Chile.

The molecular mechanisms underlying fish tolerance to soybean meal (SBM) remain unclear. Identifying these mechanisms would be beneficial, as this trait favors growth. Two fish replicates from 19 experimental families were fed fishmeal-(100FM) or SBM-based diets supplemented with saponin (50SBM + 2SPN) from juvenile to adult stages. Individuals were selected from families with a genotype-by-environment interaction higher (HG-50SBM + 2SPN, 170 ± 18 mg) or lower (LG-50SBM + 2SPN, 76 ± 10 mg) weight gain on 50SBM + 2SPN for intestinal transcriptomic analysis. A histological evaluation confirmed middle intestinal inflammation in the LG- vs. HG-50SBM + 2SPN group. Enrichment analysis of 665 differentially expressed genes (DEGs) identified pathways associated with immunity and lipid metabolism. Genes linked to intestinal immunity were downregulated in HG fish (, , , , , , ), likely dampening inflammatory responses. Conversely, genes involved in retinol signaling were upregulated (, , ), potentially favoring growth by suppressing insulin responses. Genes associated with lipid metabolism were upregulated, including key components of the SREBP (, , ) and cholesterol catabolism (), as well as the downregulation of . These results strongly suggest that transcriptomic changes in lipid metabolism mediate SBM tolerance. Genotypic variations in DEGs may become biomarkers for improving early selection of fish tolerant to SMB or others plant-based diets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/genes12050700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151431PMC
May 2021

Skin Multi-Omics-Based Interactome Analysis: Integrating the Tissue and Mucus Exuded Layer for a Comprehensive Understanding of the Teleost Mucosa Functionality as Model of Study.

Front Immunol 2020 4;11:613824. Epub 2021 Feb 4.

IRTA-SCR, Aquaculture Program, Sant Carles de la Rápita, Spain.

From a general structural perspective, a mucosal tissue is constituted by two main matrices: the tissue and the secreted mucus. Jointly, they fulfill a wide range of functions including the protection of the epithelial layer. In this study, we simultaneously analyzed the epithelial tissue and the secreted mucus response using a holistic interactome-based multi-omics approach. The effect of the gilthead sea bream () skin mucosa to a dietary inclusion of spray-dried porcine plasma (SDPP) was evaluated. The epithelial skin microarrays-based transcriptome data showed 194 differentially expressed genes, meanwhile the exuded mucus proteome analysis 35 differentially synthesized proteins. Separately, the skin transcripteractome revealed an expression profile that favored biological mechanisms associated to gene expression, biogenesis, vesicle function, protein transport and localization to the membrane. Mucus proteome showed an enhanced protective role with putatively higher antioxidant and antimicrobial properties. The integrated skin mucosa multi-interactome analysis evidenced the interrelationship and synergy between the metabolism and the exuded mucus functions improving specifically the tissue development, innate defenses, and environment recognition. Histologically, the skin increased in thickness and in number of mucous cells. A positive impact on animal performance, growth and feed efficiency was also registered. Collectively, the results suggest an intimate crosstalk between skin tissue and its exuded mucus in response to the nutritional stimulus (SDPP supplementation) that favors the stimulation of cell protein turnover and the activation of the exudation machinery in the skin mucosa. Thus, the multi-omics-based interactome analysis provides a comprehensive understanding of the biological context of response that takes place in a mucosal tissue. In perspective, this strategy is applicable for evaluating the effect of any experimental variable on any mucosal tissue functionality, including the benefits this assessment may provide on the study of the mammalian mucosa.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.613824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7890662PMC
June 2021

Analysis of the Toxin Found in the Genome of the Chilean Non-toxigenic Strain PMC53.7.

Front Cell Infect Microbiol 2020 24;10:482. Epub 2020 Sep 24.

Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.

non-toxigenic strains are responsible for about 10% of acute gastroenteritis associated with this species, suggesting they harbor unique virulence factors. toxin (Zot), firstly described in , is a secreted toxin that increases intestinal permeability. Recently, we identified Zot-encoding genes in the genomes of highly cytotoxic Chilean strains, including the non-toxigenic clinical strain PMC53.7. To gain insights into a possible role of Zot in , we analyzed whether it could be responsible for cytotoxicity. However, we observed a barely positive correlation between Caco-2 cell membrane damage and Zot mRNA expression during PMC53.7 infection and non-cytotoxicity induction in response to purified PMC53.7-Zot. Unusually, we observed a particular actin disturbance on cells infected with PMC53.7. Based on this observation, we decided to compare the sequence of PMC53.7-Zot with Zot of human pathogenic species such as , and other strains, using computational tools. The PMC53.7-Zot was compared with other toxins and identified as an endotoxin with conserved motifs in the N-terminus and a variable C-terminal region and without FCIGRL peptide. Notably, the C-terminal diversity among Zots meant that not all of them could be identified as toxins. Structurally, PMC53.7-Zot was modeled as a transmembrane protein. Our results suggested that it has partial 3D structure similarity with -Zot. Probably, the PMC53.7-Zot would affect the actin cytoskeletal, but, in the absence of FCIGRL, the mechanisms of actions must be elucidated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fcimb.2020.00482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7541967PMC
June 2021

Melatonin triggers metabolic and gene expression changes leading to improved quality traits of two sweet cherry cultivars during cold storage.

Food Chem 2020 Jul 5;319:126360. Epub 2020 Feb 5.

Centro Tecnológico de Recursos Vegetales, Escuela de Agronomía, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago 8580745, Chile. Electronic address:

Sweet cherry is a valuable non-climacteric fruit with elevated phytonutrients, whose fruit quality attributes are prone to rapid deterioration after harvest, especially peel damage and water loss of stem. Here the metabolic and transcriptional response of exogenous melatonin was assessed in two commercial cultivars of sweet cherry (Santina and Royal Rainier) during cold storage. Gene expression profiling revealed that cuticle composition and water movement may underlie the effect of melatonin in delaying weight loss. An effect of melatonin on total soluble solids and lower respiration rate was observed in both cultivars. Melatonin induces overexpression of genes related to anthocyanin biosynthesis, which correlates with increased anthocyanin levels and changes in skin color (Chroma). Our results indicate that along with modulating antioxidant metabolism, melatonin improves fruit quality traits by triggering a range of metabolic and gene expression changes, which ultimately contribute to extend sweet cherry postharvest storability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2020.126360DOI Listing
July 2020

Effectiveness of black tea versus placebo in subjects with hypercholesterolemia: A PRISMA systematic review and meta-analysis.

Diabetes Metab Syndr 2019 May - Jun;13(3):2250-2258. Epub 2019 May 23.

Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud. Universidad Autónoma de Chile, Santiago, Chile.

Aim: To determine if the black tea is more effective in serum lipid profile that placebo in subjects with hypercholesterolemia.

Design: Systematic review with meta-analysis of randomized clinical trials (RCTs).

Data Sources: The databases Medline, Central, Embase, Lilacs, Cinahl, SPORTDiscus, and Web of Science were searched from inception up to January 2019.

Eligibility Criteria For Selecting Studies: RCTs that compared black tea versus placebo, that included serum lipid profile outcomes in subjects older than 18 years of age with hypercholesterolemia.

Results: Seven RCTs met the eligibility criteria, and for the quantitative synthesis, six studies were included. Mean difference for total cholesterol was 1.67 mg/dl 95% CI = -5.47 to 8.80 (p = 0.65), mean difference 0.28 mg/dl, 95% CI = -3.89 to 4.45 (p = 0.90) for triglycerides, mean difference 3.21 mg/dl, 95% CI = -11.02 to 4.60 (p = 0.42) for low density lipoprotein-cholesterol, mean difference 0.38 mg/dl, 95% CI = -1.12 to 1.87 (p = 0.62) for high density lipoprotein-cholesterol.

Conclusion: In the short term, no significant differences were found in lipid serum profile comparing black tea consumption with placebo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.dsx.2019.05.019DOI Listing
December 2019

Conservation of Small Regulatory RNAs in : Possible role of RNA-OUT Encoded by the Pathogenicity Island (VPaI-7) of Pandemic Strains.

Int J Mol Sci 2019 Jun 10;20(11). Epub 2019 Jun 10.

Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8320000, Chile.

Small regulatory RNAs (sRNAs) are molecules that play an important role in the regulation of gene expression. sRNAs in bacteria can affect important processes, such as metabolism and virulence. Previous studies showed a significant role of sRNAs in the species, but knowledge about is limited. Here, we examined the conservation of sRNAs between and other human species, in addition to investigating the conservation between strains differing in pandemic origin. Our results showed that only 7% of sRNAs were conserved between and other species, but 88% of sRNAs were highly conserved within species. Nonetheless, two sRNAs coding to RNA-OUT, a component of the Tn10/IS10 system, were exclusively present in pandemic strains. Subsequent analysis showed that both RNA-OUT were located in pathogenicity island-7 and would interact with transposase VPA1379, according to the model of pairing of IS10-encoded antisense RNAs. According to the location of RNA-OUT/VPA1379, we also investigated if they were expressed during infection. We observed that the transcriptional level of VPA1379 was significantly increased, while RNA-OUT was decreased at three hours post-infection. We suggest that IS10 transcription increases in pandemic strains during infection, probably to favor IS10 transposition and improve their fitness when they are facing adverse conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms20112827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6601013PMC
June 2019

Comparative Transcriptome Profiling in a Segregating Peach Population with Contrasting Juiciness Phenotypes.

J Agric Food Chem 2019 Feb 24;67(5):1598-1607. Epub 2019 Jan 24.

Laboratorio de Bioinformática y Expresión Génica , Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile , Av. El Líbano 5524 , Santiago , Chile.

Cold storage of fruit is one of the methods most commonly employed to extend the postharvest lifespan of peaches ( Prunus persica (L.) Batsch). However, fruit quality in this species is affected negatively by mealiness, a physiological disorder triggered by chilling injury after long periods of exposure to low temperatures during storage and manifested mainly as a lack of juiciness, which ultimately modifies the organoleptic properties of peach fruit. The aim of this study was to identify molecular components and metabolic processes underlying mealiness in susceptible and nonsusceptible segregants. Transcriptome and qRT-PCR profiling were applied to individuals with contrasting juiciness phenotypes in a segregating F population. Our results suggest that mealiness is a multiscale phenomenon, because juicy and mealy fruit display distinctive reprogramming processes affecting translational machinery and lipid, sugar, and oxidative metabolism. The candidate genes identified may be useful tools for further crop improvement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jafc.8b05177DOI Listing
February 2019

Accessory Toxins of Pathogens and Their Role in Epithelial Disruption During Infection.

Front Microbiol 2018 20;9:2248. Epub 2018 Sep 20.

Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.

Gastrointestinal episodes associated with species have been rising worldwide in the last few years. Consequently, it is important to comprehend how occurs the production of diarrhea, to establish new preventive and therapeutic measures. Besides the classical CT and TCP toxins, Zot, RTX, and Ace among others have been deeply studied in However, in other species of clinical interest, where some of these toxins have been reported, there is practically no information. Zot activates a cascade of signals inside of the cell that increase the permeability of epithelial barrier, while RTX causes depolymerization of the actin cytoskeleton and Ace increases the permeability of intestinal cell monolayers. The goal of this study is to acquire information about the distribution of these toxins in human pathogenic and to review the progress in the study of their role in the intestinal epithelium during infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2018.02248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158335PMC
September 2018

Exploring the Genomic Traits of Non-toxigenic Strains Isolated in Southern Chile.

Front Microbiol 2018 8;9:161. Epub 2018 Feb 8.

Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.

is the leading cause of seafood-borne gastroenteritis worldwide. As reported in other countries, after the rise and fall of the pandemic strain in Chile, other post-pandemic strains have been associated with clinical cases, including strains lacking the major toxins TDH and TRH. Since the presence or absence of and genes has been used for diagnostic purposes and as a proxy of the virulence of isolates, the understanding of virulence in strains lacking toxins is essential to detect these strains present in water and marine products to avoid possible food-borne infection. In this study, we characterized the genome of four environmental and two clinical non-toxigenic strains (-, -, and T3SS2-). Using whole-genome sequencing, phylogenetic, and comparative genome analysis, we identified the core and pan-genome of of strains of southern Chile. The phylogenetic tree based on the core genome showed low genetic diversity but the analysis of the pan-genome revealed that all strains harbored genomic islands carrying diverse virulence and fitness factors or prophage-like elements that encode toxins like Zot and RTX. Interestingly, the three strains carrying Zot-like toxin have a different sequence, although the alignment showed some conserved areas with the sequence found in . In addition, we identified an unexpected diversity in the genetic architecture of the T3SS1 gene cluster and the presence of the T3SS2 gene cluster in a non-pandemic environmental strain. Our study sheds light on the diversity of strains from the southern Pacific which increases our current knowledge regarding the global diversity of this organism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2018.00161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5809470PMC
February 2018

Administration of high doses of copper to capuchin monkeys does not cause liver damage but induces transcriptional activation of hepatic proliferative responses.

J Nutr 2012 Feb 5;142(2):233-7. Epub 2012 Jan 5.

Institute of Nutrition and Food Technology, Universidad de Chile, Santiago, Chile.

Liver cells respond to copper loading upregulating protective mechanisms. However, to date, except for liver content, there are no good indicators that identify individuals with excess liver copper. We hypothesized that administering high doses of copper to young (5.5 mg Cu · kg⁻¹ . d⁻¹) and adult (7.5 mg Cu · kg⁻¹ . d⁻¹) capuchin monkeys would induce detectable liver damage. Study groups included adult monkeys (2 females, 2 males) 3-3.5 y old at enrollment treated with copper for 36 mo (ACu); age-matched controls (1 female, 3 males) that did not receive additional copper (AC); young monkeys (2 female, 2 males) treated from birth with copper for 36 mo (YCu); and young age-matched controls (2 female, 2 males) that did not receive additional copper (YC). We periodically assessed clinical, blood biochemical, and liver histological indicators and at 36 mo the hepatic mRNA abundance of MT2a, APP, DMT1, CTR1, HGF, TGFβ, and NFκΒ only in adult monkeys. After 36 mo, the liver copper concentration was 4-5 times greater in treated monkeys relative to controls. All monkeys remained healthy with normal routine serum biochemical indices and there was no evidence of liver tissue damage. Relative mRNA abundance of HGF, TGFβ and NFκB was significantly greater in ACu than in AC monkeys. In conclusion, capuchin monkeys exposed to copper at doses up to 50 times the current upper level enhanced expression of genes related to inflammation and injury without clinical, blood biochemical, or histological evidence of liver damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3945/jn.111.140103DOI Listing
February 2012

Alteration of gene expression profile in Niemann-Pick type C mice correlates with tissue damage and oxidative stress.

PLoS One 2011 22;6(12):e28777. Epub 2011 Dec 22.

Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.

Background: Niemann-Pick type C disease (NPC) is a neurovisceral lipid storage disorder mainly characterized by unesterified cholesterol accumulation in lysosomal/late endosomal compartments, although there is also an important storage for several other kind of lipids. The main tissues affected by the disease are the liver and the cerebellum. Oxidative stress has been described in various NPC cells and tissues, such as liver and cerebellum. Although considerable alterations occur in the liver, the pathological mechanisms involved in hepatocyte damage and death have not been clearly defined. Here, we assessed hepatic tissue integrity, biochemical and oxidative stress parameters of wild-type control (Npc1(+/+); WT) and homozygous-mutant (Npc1(-/-); NPC) mice. In addition, the mRNA abundance of genes encoding proteins associated with oxidative stress, copper metabolism, fibrosis, inflammation and cholesterol metabolism were analyzed in livers and cerebella of WT and NPC mice.

Methodology/principal Findings: We analyzed various oxidative stress parameters in the liver and hepatic and cerebellum gene expression in 7-week-old NPC1-deficient mice compared with control animals. We found signs of inflammation and fibrosis in NPC livers upon histological examination. These signs were correlated with increased levels of carbonylated proteins, diminished total glutathione content and significantly increased total copper levels in liver tissue. Finally, we analyzed liver and cerebellum gene expression patterns by qPCR and microarray assays. We found a correlation between fibrotic tissue and differential expression of hepatic as well as cerebellar genes associated with oxidative stress, fibrosis and inflammation in NPC mice.

Conclusions/significance: In NPC mice, liver disease is characterized by an increase in fibrosis and in markers associated with oxidative stress. NPC is also correlated with altered gene expression, mainly of genes involved in oxidative stress and fibrosis. These findings correlate with similar parameters in cerebellum, as has been previously reported in the NPC mice model.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028777PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3245218PMC
May 2012

Genome-wide identification of new Wnt/beta-catenin target genes in the human genome using CART method.

BMC Genomics 2010 Jun 1;11:348. Epub 2010 Jun 1.

Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile, Santiago, Chile.

Background: The importance of in silico predictions for understanding cellular processes is now widely accepted, and a variety of algorithms useful for studying different biological features have been designed. In particular, the prediction of cis regulatory modules in non-coding human genome regions represents a major challenge for understanding gene regulation in several diseases. Recently, studies of the Wnt signaling pathway revealed a connection with neurodegenerative diseases such as Alzheimer's. In this article, we construct a classification tool that uses the transcription factor binding site motifs composition of some gene promoters to identify new Wnt/beta-catenin pathway target genes potentially involved in brain diseases.

Results: In this study, we propose 89 new Wnt/beta-catenin pathway target genes predicted in silico by using a method based on multiple Classification and Regression Tree (CART) analysis. We used as decision variables the presence of transcription factor binding site motifs in the upstream region of each gene. This prediction was validated by RT-qPCR in a sample of 9 genes. As expected, LEF1, a member of the T-cell factor/lymphoid enhancer-binding factor family (TCF/LEF1), was relevant for the classification algorithm and, remarkably, other factors related directly or indirectly to the inflammatory response and amyloidogenic processes also appeared to be relevant for the classification. Among the 89 new Wnt/beta-catenin pathway targets, we found a group expressed in brain tissue that could be involved in diverse responses to neurodegenerative diseases, like Alzheimer's disease (AD). These genes represent new candidates to protect cells against amyloid beta toxicity, in agreement with the proposed neuroprotective role of the Wnt signaling pathway.

Conclusions: Our multiple CART strategy proved to be an effective tool to identify new Wnt/beta-catenin pathway targets based on the study of their regulatory regions in the human genome. In particular, several of these genes represent a new group of transcriptional dependent targets of the canonical Wnt pathway. The functions of these genes indicate that they are involved in pathophysiology related to Alzheimer's disease or other brain disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2164-11-348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996972PMC
June 2010

Calcium/calmodulin-dependent protein kinase type IV is a target gene of the Wnt/beta-catenin signaling pathway.

J Cell Physiol 2009 Dec;221(3):658-67

Centro Basal de Excelencia para el Envejecimiento y Regeneración CARE, Centro de Regulación Celular y Patología Joaquín V Luco (CRCP) and MIFAB, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.

Calcium/calmodulin-dependent protein kinase IV (CaMKIV) plays a key role in the regulation of calcium-dependent gene expression. The expression of CaMKIV and the activation of CREB regulated genes are involved in memory and neuronal survival. We report here that: (a) a bioinformatic analysis of 15,476 promoters of the human genome predicted several Wnt target genes, being CaMKIV a very interesting candidate; (b) CaMKIV promoter contains TCF/LEF transcription motifs similar to those present in Wnt target genes; (c) biochemical studies indicate that lithium and the canonical ligand Wnt-3a induce CaMKIV mRNA and protein expression levels in rat hippocampal neurons as well as CaMKIV promoter activity; (d) treatment of hippocampal neurons with Wnt-3a increases the binding of beta-catenin to the CaMKIV promoter: (e) In vivo activation of the Wnt signaling improve spatial memory impairment and restores the expression of CaMKIV in a mice double transgenic model for Alzheimer's disease which shows decreased levels of the kinase. We conclude that CaMKIV is regulated by the Wnt signaling pathway and that its expression could play a role in the neuroprotective function of the Wnt signaling against the Alzheimer's amyloid peptide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcp.21902DOI Listing
December 2009

Molecular characterization of a novel patched-related protein in Apis mellifera and Drosophila melanogaster.

Arch Insect Biochem Physiol 2008 Jul;68(3):156-70

Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile, Macul 5540, CP 138-11, Santiago, Chile.

The molecular identification and characterization of the patched-related (ptr) gene and protein in Apis mellifera and Drosophila melanogaster are reported. Ptr proteins are closely related in predicted topology and domain organization to the protein encoded by the Drosophila segment polarity gene patched. Ptrs have 12 potential transmembrane domains arranged in two sets of 1+5 membrane-spanning segments containing a conserved sterol-sensing domain (SSD) and functional GxxxD and PPXY motifs. Phylogenetic analysis showed that Ptrs belong to a previously uncharacterized class of insect proteins that share a high level of sequence identity. Analysis using quantitative real-time polymerase chain reaction (qPCR) indicates that ptr gene is preferentially expressed during embryo stages of A. mellifera development; interestingly, this pattern of temporal expression was also observed for the D. melanogaster homologue, suggesting that these proteins might be involved in embryo morphogenesis. To understand Ptr function at the molecular level, we investigated the subcellular distribution of DmPtr. We have shown by biochemical analysis that DmPtr protein is tightly associated with membranes. Consistently, Ptr immunoreactivity appears to be localized at the sites of membrane furrow formation during cellularization of D. melanogaster embryos. These studies indicated that Ptrs belong to a previously uncharacterized class of insect transmembrane proteins that share a high level of sequence identity. Our analysis of ptr gene expression and protein localization suggest that Ptr might fulfil a developmental role by participating in processes that require growth and stabilization of plasma membrane.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/arch.20245DOI Listing
July 2008

Identification of woolliness response genes in peach fruit after post-harvest treatments.

J Exp Bot 2008 3;59(8):1973-86. Epub 2008 May 3.

Laboratorio de Bioinformática y Expresión Génica, INTA-Universidad de Chile, Millennium Nucleus Center for Genomics of the Cell (CGC), Santiago, Chile.

Woolliness is a physiological disorder of peaches and nectarines that becomes apparent when fruit are ripened after prolonged periods of cold storage. This disorder is of commercial importance since shipping of peaches to distant markets and storage before selling require low temperature. However, knowledge about the molecular basis of peach woolliness is still incomplete. To address this issue, a nylon macroarray containing 847 non-redundant expressed sequence tags (ESTs) from a ripe peach fruit cDNA library was developed and used. Gene expression changes of peach fruit (Prunus persica cv. O'Henry) ripened for 7 d at 21 degrees C (juicy fruit) were compared with those of fruit stored for 15 d at 4 degrees C and then ripened for 7 d at 21 degrees C (woolly fruit). A total of 106 genes were found to be differentially expressed between juicy and woolly fruit. Data analysis indicated that the activity of most of these genes (>90%) was repressed in the woolly fruit. In cold-stored peaches (cv. O'Henry), the expression level of selected genes (cobra, endopolygalacturonase, cinnamoyl-CoA-reductase, and rab11) was lower than in the juicy fruit, and it remained low in woolly peaches after ripening, a pattern that was conserved in woolly fruit from two other commercial cultivars (cv. Flamekist and cv. Elegant Lady). In addition, the results of this study indicate that molecular changes during fruit woolliness involve changes in the expression of genes associated with cell wall metabolism and endomembrane trafficking. Overall, the results reported here provide an initial characterization of the transcriptome activity of peach fruit under different post-harvest treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/ern069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2413281PMC
July 2008
-->