Luis Eduardo Diaz | Universidad de La Sabana (original) (raw)
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Papers by Luis Eduardo Diaz
The open microbiology journal, 2018
New strategies have been arisen to set a rapid and effective screening for selection of microorga... more New strategies have been arisen to set a rapid and effective screening for selection of microorganism with bioactive potential. This study suggests that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents. An unstudied microbial community from a tropical river sediment in Colombian Orinoquía is described, applying an extended cultivation strategy using physicochemical pretreatments, biological screenings and taxonomic dereplication through MALDI-TOF MS approach. Actinobacteria-like isolates (790) were growth and their antimicrobial activity was assessed against methicillin-resistant , Vancomycin-resistant , extended-spectrum β-lactamase , and clinical isolates of and Seventy-eight isolates, belonging to the Streptomycetaceae family according to 16S rDNA analysis were found to have antimicrobial activity and w...
BMC microbiology, Jan 8, 2017
Water evaporation in solar salterns creates salinity gradients that promote the adaptation of mic... more Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against mul...
Journal of biomaterials science. Polymer edition, Jan 21, 2016
The objective of this study was to assess the effects of type of polyol and concentration of poly... more The objective of this study was to assess the effects of type of polyol and concentration of polycaprolactone (PCL) in polyurethanes (PUs) on microbial degradability, cytotoxicity, biological properties and antibacterial activity to establish whether these materials may have biomedical applications. Chemically modified and unmodified castor oil, PCL and isophorone diisocyanate in a 1:1 ratio of NCO/OH were used. PUs were characterized by stress/strain fracture tests and hardness (ASTM D 676-59). Hydrophilic character was determined by contact angle trials and morphology was evaluated by scanning electron microscopy (SEM). Degradability with Escherichia coli and Pseudomonas aeruginosa was evaluated by measuring variations in the weight of the polymers. Cytotoxicity was evaluated using the ISO 10993-5 (MTT) method with mouse embryonic fibroblasts L-929 (ATCC CCL-1) in direct contact with the PUs and with NIH/3T3 cells (ATCC CRL-1658) in indirect contact with the PUs. Antimicrobial act...
Vitae, 2012
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Revista Colombiana De Quimica, Feb 14, 2010
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Revista Colombiana de Quimica
Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and TissueInhibitor-1 ofMMPs (TIMP-1) could contribu... more Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and TissueInhibitor-1 ofMMPs (TIMP-1) could contribute to regulate the invasive behaviour of trophoblastic cells, effect which could be mediated by Insulin-like growth factor type II (IGF-II), which regulates the development and function of trophoblast at the foetal-maternal interface. The aim of this study was to investigate the role of the PI3K/AKT signalling pathway activated by IGF-II in the expression of MMP-2 and MMP-9 involved in the invasion process in the human choriocarcinoma cell line JEG-3. MMP-2, MMP-9 and TIMP-1 mARN expression in those cells were evaluated by RT-PCR using different IGF-II doses and conditions while signalling pathway was evaluated using Western blot. It was found that IGF-II does not contribute to trophoblastic cells proliferation, however, it promotes mARN expression of MMP-9 and TIMP-1, but not of MMP-2, in a dose-dependent way. The effect on MMP-9 expression is mediated through IGF-II activation of PI3K/...
![Research paper thumbnail of [Immunocytochemical and molecular studies with primary cultures of molar tissue]](https://attachments.academia-assets.com/71733832/thumbnails/1.jpg)
](Biomédica : revista del Instituto Nacional de Salud, 2006
Gestational trophoblastic disease includes a group of pathologies characterized by abnormal troph... more Gestational trophoblastic disease includes a group of pathologies characterized by abnormal trophoblast growth and invasion. The molecular bases of the disease are largely unknown, due in part to the lack of appropriate biological models. The insulin-like growth factor (IGF) system plays a fundamental role in the growth and development of many tissues and is involved in the progression of several diseases. Primary cell cultures derived from first trimester placenta were characterized from patients with complete hydatidiform mole and spontaneous non molar abortion by immunocytochemical and molecular methods. The immunocytochemical method used specific markers for trophoblastic cells, whereas RT-PCR was used to identify insulin-like growth factor gene expression. Histochemical staining with hematoxilin-eosin revealed that the cultures contained heterogeneous cell types, including trophoblast and endometrial decidual cells. The ratio of trophoblast cells in the cultures varied between ...
Biomédica, 2006
Materials and Methods. The immunocytochemical method used specific markers for trophoblastic cell... more Materials and Methods. The immunocytochemical method used specific markers for trophoblastic cells, whereas RT-PCR was used to identify insulin-like growth factor gene expression. Results. Histochemical staining with hematoxilin-eosin revealed that the cultures contained heterogeneous cell types, including trophoblast and endometrial decidual cells. The ratio of trophoblast cells in the cultures varied between 16% and 37%, as detected by cytokeratine-7 as the specific trophoblast marker. Gene expression analysis corroborated the presence of trophoblasts by detecting insulin-like growth factor II mRNA, whereas GH-V transcripts were correlated with the presence of syncitiotrophoblasts. Insulin-like growth factor I and insulin-like growth factor binding protein 1 mRNAs were related to mesenchyimal and decidual cells, respectively. Higher insulin-like growth factor II expression levels were found in molar tissues in comparison with non-molar abortions. Conclusion. By combining three methodologies-morphology, immunocytochemistry and gene expression, characterization and follow-up of placenta cultures from abnormal tissues is found to facilitate diagnosis.
Molecules, 2012
Phenolic compounds are widely distributed in Nature and act as pharmacologically active constitue... more Phenolic compounds are widely distributed in Nature and act as pharmacologically active constituents in many herbal medicines. They have multiple biological properties, most notably antioxidant, antibacterial and cytotoxic activities. In the present study an attempt to correlate the phenolic composition of leaf, flower and wood extracts of Piper imperiale, with antioxidant, antitubercular and cytotoxic activities was undertaken. The total phenol content ranged from 1.98 to 6.94 mg GAE/gDW among ethanolic extracts, and gallic acid, catechin, epicatechin, ferulic acid, resveratrol and quercetin were identified and quantified by HPLC. DPPH and ABTS assays showed high antioxidant activity of the leaf extract (EC 50ABTS = 15.6 µg/mL, EC 50DPPH = 27.3 µg/mL) with EC 50 in the same order of magnitude as the hydroxyquinone (EC 50ABTS = 10.2 µg/mL, EC 50DPPH = 15.7 µg/mL). The flower extract showed strong antimicrobial activity against Mycobacterium tuberculosis H 37 Rv. All the extracts exhibited dose-dependent cytotoxic effects against MCF-7 cancer cells. This is the first time that a Piper extract has been found to be highly active against M. tuberculosis. This study shows the biological potential of Piper imperiale extracts and gives way to bio-guided studies with well-defined biological activities.
Molecular Human Reproduction, 2007
Choriocarcinoma is a highly malignant tumor that can arise from trophoblasts of any type of gesta... more Choriocarcinoma is a highly malignant tumor that can arise from trophoblasts of any type of gestational event but most often from complete hydatidiform mole. IGF-II plays a fundamental role in placental development and may play a role in gestational trophoblastic diseases. Several studies have shown that IGF-II is expressed at high levels in hydatidiform moles and choriocarcinoma tissues; however, conflicting data exist on how IGF-II regulates the behaviour of choriocarcinoma cells. The purpose of this study was to determine the contribution of the receptors for IGF-I and insulin to the actions of IGF-II on the regulation of choriocarcinoma cells metastasis. An Immuno Radio Metric Assay was used to analyse the circulating and tissue levels of IGF-I and IGF-II in 24 cases of hydatidiform mole, two cases of choriocarcinoma and eight cases of spontaneous abortion at the same gestational age. The JEG-3 choriocarcinoma cell line was used to investigate the role of IGF-II in the regulation of cell invasion. We found that mole and choriocarcinoma tissue express high levels of IGF-II compared to first trimester placenta. Both IGF-I and IGF-II regulate choriocarcinoma cell invasion in a dose dependent manner but through a different mechanism. IGF-II effects involve the activation of the InsR while IGF-I uses the IGF-IR. The positive effects of IGF-II on invasion are the result of enhanced cell adhesion and chemotaxis (specifically towards collagen IV). The actions of IGF-II but not those of IGF-I were sensitive to inhibition by the insulin receptor inhibitor HNMPA(AM) 3. Our results demonstrate that the insulin receptor regulates choriocarcinoma cell invasion.
The open microbiology journal, 2018
New strategies have been arisen to set a rapid and effective screening for selection of microorga... more New strategies have been arisen to set a rapid and effective screening for selection of microorganism with bioactive potential. This study suggests that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents. An unstudied microbial community from a tropical river sediment in Colombian Orinoquía is described, applying an extended cultivation strategy using physicochemical pretreatments, biological screenings and taxonomic dereplication through MALDI-TOF MS approach. Actinobacteria-like isolates (790) were growth and their antimicrobial activity was assessed against methicillin-resistant , Vancomycin-resistant , extended-spectrum β-lactamase , and clinical isolates of and Seventy-eight isolates, belonging to the Streptomycetaceae family according to 16S rDNA analysis were found to have antimicrobial activity and w...
BMC microbiology, Jan 8, 2017
Water evaporation in solar salterns creates salinity gradients that promote the adaptation of mic... more Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against mul...
Journal of biomaterials science. Polymer edition, Jan 21, 2016
The objective of this study was to assess the effects of type of polyol and concentration of poly... more The objective of this study was to assess the effects of type of polyol and concentration of polycaprolactone (PCL) in polyurethanes (PUs) on microbial degradability, cytotoxicity, biological properties and antibacterial activity to establish whether these materials may have biomedical applications. Chemically modified and unmodified castor oil, PCL and isophorone diisocyanate in a 1:1 ratio of NCO/OH were used. PUs were characterized by stress/strain fracture tests and hardness (ASTM D 676-59). Hydrophilic character was determined by contact angle trials and morphology was evaluated by scanning electron microscopy (SEM). Degradability with Escherichia coli and Pseudomonas aeruginosa was evaluated by measuring variations in the weight of the polymers. Cytotoxicity was evaluated using the ISO 10993-5 (MTT) method with mouse embryonic fibroblasts L-929 (ATCC CCL-1) in direct contact with the PUs and with NIH/3T3 cells (ATCC CRL-1658) in indirect contact with the PUs. Antimicrobial act...
Vitae, 2012
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Revista Colombiana De Quimica, Feb 14, 2010
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Revista Colombiana de Quimica
Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and TissueInhibitor-1 ofMMPs (TIMP-1) could contribu... more Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and TissueInhibitor-1 ofMMPs (TIMP-1) could contribute to regulate the invasive behaviour of trophoblastic cells, effect which could be mediated by Insulin-like growth factor type II (IGF-II), which regulates the development and function of trophoblast at the foetal-maternal interface. The aim of this study was to investigate the role of the PI3K/AKT signalling pathway activated by IGF-II in the expression of MMP-2 and MMP-9 involved in the invasion process in the human choriocarcinoma cell line JEG-3. MMP-2, MMP-9 and TIMP-1 mARN expression in those cells were evaluated by RT-PCR using different IGF-II doses and conditions while signalling pathway was evaluated using Western blot. It was found that IGF-II does not contribute to trophoblastic cells proliferation, however, it promotes mARN expression of MMP-9 and TIMP-1, but not of MMP-2, in a dose-dependent way. The effect on MMP-9 expression is mediated through IGF-II activation of PI3K/...
Biomédica : revista del Instituto Nacional de Salud, 2006
Gestational trophoblastic disease includes a group of pathologies characterized by abnormal troph... more Gestational trophoblastic disease includes a group of pathologies characterized by abnormal trophoblast growth and invasion. The molecular bases of the disease are largely unknown, due in part to the lack of appropriate biological models. The insulin-like growth factor (IGF) system plays a fundamental role in the growth and development of many tissues and is involved in the progression of several diseases. Primary cell cultures derived from first trimester placenta were characterized from patients with complete hydatidiform mole and spontaneous non molar abortion by immunocytochemical and molecular methods. The immunocytochemical method used specific markers for trophoblastic cells, whereas RT-PCR was used to identify insulin-like growth factor gene expression. Histochemical staining with hematoxilin-eosin revealed that the cultures contained heterogeneous cell types, including trophoblast and endometrial decidual cells. The ratio of trophoblast cells in the cultures varied between ...
Biomédica, 2006
Materials and Methods. The immunocytochemical method used specific markers for trophoblastic cell... more Materials and Methods. The immunocytochemical method used specific markers for trophoblastic cells, whereas RT-PCR was used to identify insulin-like growth factor gene expression. Results. Histochemical staining with hematoxilin-eosin revealed that the cultures contained heterogeneous cell types, including trophoblast and endometrial decidual cells. The ratio of trophoblast cells in the cultures varied between 16% and 37%, as detected by cytokeratine-7 as the specific trophoblast marker. Gene expression analysis corroborated the presence of trophoblasts by detecting insulin-like growth factor II mRNA, whereas GH-V transcripts were correlated with the presence of syncitiotrophoblasts. Insulin-like growth factor I and insulin-like growth factor binding protein 1 mRNAs were related to mesenchyimal and decidual cells, respectively. Higher insulin-like growth factor II expression levels were found in molar tissues in comparison with non-molar abortions. Conclusion. By combining three methodologies-morphology, immunocytochemistry and gene expression, characterization and follow-up of placenta cultures from abnormal tissues is found to facilitate diagnosis.
Molecules, 2012
Phenolic compounds are widely distributed in Nature and act as pharmacologically active constitue... more Phenolic compounds are widely distributed in Nature and act as pharmacologically active constituents in many herbal medicines. They have multiple biological properties, most notably antioxidant, antibacterial and cytotoxic activities. In the present study an attempt to correlate the phenolic composition of leaf, flower and wood extracts of Piper imperiale, with antioxidant, antitubercular and cytotoxic activities was undertaken. The total phenol content ranged from 1.98 to 6.94 mg GAE/gDW among ethanolic extracts, and gallic acid, catechin, epicatechin, ferulic acid, resveratrol and quercetin were identified and quantified by HPLC. DPPH and ABTS assays showed high antioxidant activity of the leaf extract (EC 50ABTS = 15.6 µg/mL, EC 50DPPH = 27.3 µg/mL) with EC 50 in the same order of magnitude as the hydroxyquinone (EC 50ABTS = 10.2 µg/mL, EC 50DPPH = 15.7 µg/mL). The flower extract showed strong antimicrobial activity against Mycobacterium tuberculosis H 37 Rv. All the extracts exhibited dose-dependent cytotoxic effects against MCF-7 cancer cells. This is the first time that a Piper extract has been found to be highly active against M. tuberculosis. This study shows the biological potential of Piper imperiale extracts and gives way to bio-guided studies with well-defined biological activities.
Molecular Human Reproduction, 2007
Choriocarcinoma is a highly malignant tumor that can arise from trophoblasts of any type of gesta... more Choriocarcinoma is a highly malignant tumor that can arise from trophoblasts of any type of gestational event but most often from complete hydatidiform mole. IGF-II plays a fundamental role in placental development and may play a role in gestational trophoblastic diseases. Several studies have shown that IGF-II is expressed at high levels in hydatidiform moles and choriocarcinoma tissues; however, conflicting data exist on how IGF-II regulates the behaviour of choriocarcinoma cells. The purpose of this study was to determine the contribution of the receptors for IGF-I and insulin to the actions of IGF-II on the regulation of choriocarcinoma cells metastasis. An Immuno Radio Metric Assay was used to analyse the circulating and tissue levels of IGF-I and IGF-II in 24 cases of hydatidiform mole, two cases of choriocarcinoma and eight cases of spontaneous abortion at the same gestational age. The JEG-3 choriocarcinoma cell line was used to investigate the role of IGF-II in the regulation of cell invasion. We found that mole and choriocarcinoma tissue express high levels of IGF-II compared to first trimester placenta. Both IGF-I and IGF-II regulate choriocarcinoma cell invasion in a dose dependent manner but through a different mechanism. IGF-II effects involve the activation of the InsR while IGF-I uses the IGF-IR. The positive effects of IGF-II on invasion are the result of enhanced cell adhesion and chemotaxis (specifically towards collagen IV). The actions of IGF-II but not those of IGF-I were sensitive to inhibition by the insulin receptor inhibitor HNMPA(AM) 3. Our results demonstrate that the insulin receptor regulates choriocarcinoma cell invasion.