2018 |
Remonsellez, F; Castro-Severyn, J; Pardo-Este, C; Aguilar, P; Fortt, J; Salinas, C; Barahona, S; Leon, J; Fuentes, B; Areche, C; Hernandez, K L; Aguayo, D; Saavedra, C P Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium Sp Sh31 Isolated from Sediments of Salar De Huasco, Chilean Altiplano Artículo de revista Frontiers in Microbiology, 9 , 2018, ISSN: 1664-302x. Resumen | Enlaces | BibTeX | Etiquetas: altiplano, altitude bacillus-subtilis, bacterium, biofilm chilean communities, compatible environmental exiguobacterium, extremophile, formation, halophilic halotolerant, microbial moderately permafrost, pressure, psychrophilic responses saline siberian solutes, sp-nov., stress wetland @article{RN380, title = {Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium Sp Sh31 Isolated from Sediments of Salar De Huasco, Chilean Altiplano}, author = { F. Remonsellez and J. Castro-Severyn and C. Pardo-Este and P. Aguilar and J. Fortt and C. Salinas and S. Barahona and J. Leon and B. Fuentes and C. Areche and K.L. Hernandez and D. Aguayo and C.P. Saavedra}, url = {/brokenurl#<Go to ISI>://WOS:000445093500001}, doi = {10.3389/fmicb.2018.02228}, issn = {1664-302x}, year = {2018}, date = {2018-01-01}, journal = {Frontiers in Microbiology}, volume = {9}, abstract = {Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival.}, keywords = {altiplano, altitude bacillus-subtilis, bacterium, biofilm chilean communities, compatible environmental exiguobacterium, extremophile, formation, halophilic halotolerant, microbial moderately permafrost, pressure, psychrophilic responses saline siberian solutes, sp-nov., stress wetland}, pubstate = {published}, tppubtype = {article} } Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival. |
Villalobos, V; Leiva, A; Rios, H; Pavez, J; Silva, C P; Ahmar, M; Queneau, Y; Blamey, J M; Chavez, F P; Urzúa, M Inhibiting Pathogen Surface Adherence by Multilayer Polyelectrolyte Films Functionalized with Glucofuranose Derivatives Artículo de revista Acs Applied Materials & Interfaces, 10 (33), pp. 28147-28158, 2018, ISSN: 1944-8244. Resumen | Enlaces | BibTeX | Etiquetas: antibacterial bacterial, biofilm biomaterials, carbohydrate challenges coatings, construction, formation, inhibition, mechanisms, p. polyelectrolytes, resistance, s. surfaces, typhimurium @article{RN403, title = {Inhibiting Pathogen Surface Adherence by Multilayer Polyelectrolyte Films Functionalized with Glucofuranose Derivatives}, author = { V. Villalobos and A. Leiva and H. Rios and J. Pavez and C.P. Silva and M. Ahmar and Y. Queneau and J.M. Blamey and F.P. Chavez and M. Urz\'{u}a}, url = {/brokenurl#<Go to ISI>://WOS:000442706600064}, doi = {10.1021/acsami.8b03605}, issn = {1944-8244}, year = {2018}, date = {2018-01-01}, journal = {Acs Applied Materials & Interfaces}, volume = {10}, number = {33}, pages = {28147-28158}, abstract = {Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here, we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces. When the film was composed of more than 10 layers, the bacterial population was greatly reduced, while the bacteria remaining on the film were morphologically damaged, as atomic force microscopy revealed. The antibacterial capacity of the polyelectrolyte films was determined by the combination of thickness, wettability, surface energy, and most importantly, the conformation that polyelectrolytes adopt the function of nature of the carbohydrate group. This polyelectrolyte film constitutes the first green approach to preventing pathogenic bacterial surface adherence and proliferation without killing the bacterial pathogen.}, keywords = {antibacterial bacterial, biofilm biomaterials, carbohydrate challenges coatings, construction, formation, inhibition, mechanisms, p. polyelectrolytes, resistance, s. surfaces, typhimurium}, pubstate = {published}, tppubtype = {article} } Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here, we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces. When the film was composed of more than 10 layers, the bacterial population was greatly reduced, while the bacteria remaining on the film were morphologically damaged, as atomic force microscopy revealed. The antibacterial capacity of the polyelectrolyte films was determined by the combination of thickness, wettability, surface energy, and most importantly, the conformation that polyelectrolytes adopt the function of nature of the carbohydrate group. This polyelectrolyte film constitutes the first green approach to preventing pathogenic bacterial surface adherence and proliferation without killing the bacterial pathogen. |
2017 |
Yempala, T; Cassels, B K Synthesis, Scope, H-1 and C-13 Spectral Assignments of Isomeric Dibenzofuran Carboxaldehydes Artículo de revista Research on Chemical Intermediates, 43 (3), pp. 1291-1299, 2017, ISSN: 0922-6168. Resumen | Enlaces | BibTeX | Etiquetas: beta-phenylethylamines bond c-13, copd, d]furan aldehyde and arylation, derivatives, design direct discovery, formation, h-1, inhibitors, nbome nmr, potential pulmonary-disease receptors, regioisomers, serotonin, treatment @article{RN345, title = {Synthesis, Scope, H-1 and C-13 Spectral Assignments of Isomeric Dibenzofuran Carboxaldehydes}, author = { T. Yempala and B.K. Cassels}, url = {/brokenurl#<Go to ISI>://WOS:000394374600002}, doi = {10.1007/s11164-016-2698-1}, issn = {0922-6168}, year = {2017}, date = {2017-01-01}, journal = {Research on Chemical Intermediates}, volume = {43}, number = {3}, pages = {1291-1299}, abstract = {Two isomeric dibenzofuran carboxaldehydes, namely 2-methoxydibenzo[b,d]furan-1-carbaldehyde (4) and 2-methoxydibenzo[b,d]furan-3-carbaldehyde (5), were synthesized. Formylation of 2-methoxydibenzo[b,d]furan (3) with alpha,alpha-dichloromethyl methyl ether and tin(IV) chloride gave a mixture of aldehydes 4 and 5 in 95 % yield and in a 35:65 ratio. Their H-1 and C-13 NMR spectral signals were not sufficiently resolved in CDCl3 solution to achieve their complete assignment, but this was possible in DMSO-d (6) with the help of 2D-NMR techniques: NOESY for H-1-H-1 interactions and HSQC and HMQC experiments for H-1-C-13 correlations. These aldehydes were used in the synthesis of novel beta-phenylethylamines and NBOMe derivatives, which are undergoing biological evaluation.}, keywords = {beta-phenylethylamines bond c-13, copd, d]furan aldehyde and arylation, derivatives, design direct discovery, formation, h-1, inhibitors, nbome nmr, potential pulmonary-disease receptors, regioisomers, serotonin, treatment}, pubstate = {published}, tppubtype = {article} } Two isomeric dibenzofuran carboxaldehydes, namely 2-methoxydibenzo[b,d]furan-1-carbaldehyde (4) and 2-methoxydibenzo[b,d]furan-3-carbaldehyde (5), were synthesized. Formylation of 2-methoxydibenzo[b,d]furan (3) with alpha,alpha-dichloromethyl methyl ether and tin(IV) chloride gave a mixture of aldehydes 4 and 5 in 95 % yield and in a 35:65 ratio. Their H-1 and C-13 NMR spectral signals were not sufficiently resolved in CDCl3 solution to achieve their complete assignment, but this was possible in DMSO-d (6) with the help of 2D-NMR techniques: NOESY for H-1-H-1 interactions and HSQC and HMQC experiments for H-1-C-13 correlations. These aldehydes were used in the synthesis of novel beta-phenylethylamines and NBOMe derivatives, which are undergoing biological evaluation. |
Cornejo, A; Sandoval, F A; Caballero, L; Machuca, L; Munoz, P; Caballero, J; Perry, G; Ardiles, A; Areche, C; Melo, F Rosmarinic Acid Prevents Fibrillization and Diminishes Vibrational Modes Associated to Beta Sheet in Tau Protein Linked to Alzheimer's Disease Artículo de revista Journal of Enzyme Inhibition and Medicinal Chemistry, 32 (1), pp. 945-953, 2017, ISSN: 1475-6366. Resumen | Enlaces | BibTeX | Etiquetas: alzheimer's amyloid beta-sheet, carnosic cells criteria, disease, fibril filaments, formation, helical in-vitro, inhibition, inhibitors, mice, neuropathologic paired pharmacophore, salvia-officinalis, tau transgenic @article{RN337, title = {Rosmarinic Acid Prevents Fibrillization and Diminishes Vibrational Modes Associated to Beta Sheet in Tau Protein Linked to Alzheimer's Disease}, author = { A. Cornejo and F.A. Sandoval and L. Caballero and L. Machuca and P. Munoz and J. Caballero and G. Perry and A. Ardiles and C. Areche and F. Melo}, url = {/brokenurl#<Go to ISI>://WOS:000406130000006}, doi = {10.1080/14756366.2017.1347783}, issn = {1475-6366}, year = {2017}, date = {2017-01-01}, journal = {Journal of Enzyme Inhibition and Medicinal Chemistry}, volume = {32}, number = {1}, pages = {945-953}, abstract = {Alzheimer's disease is a common tauopathy where fibril formation and aggregates are the hallmark of the disease. Efforts targeting amyloid-beta plaques have succeeded to remove plaques but failed in clinical trials to improve cognition; thus, the current therapeutic strategy is at preventing tau aggregation. Here, we demonstrated that four phenolic diterpenoids and rosmarinic acid inhibit fibrillization. Since, rosmarinic acid was the most active compound, we observe morphological changes in atomic force microscopy images after treatment. Hence, rosmarinic acid leads to a decrease in amide regions I and III, indicating that rosmarinic acid prevents beta-sheet assembly. Molecular docking study inside the steric zipper model of the hexapeptide (306)VQIVYK(311) involved in fibrillization and beta sheet formation, suggests that rosmarinic acid binds to the steric zipper with similar chemical interactions with respect to those observed for orange G, a known pharmacofore for amyloid.}, keywords = {alzheimer's amyloid beta-sheet, carnosic cells criteria, disease, fibril filaments, formation, helical in-vitro, inhibition, inhibitors, mice, neuropathologic paired pharmacophore, salvia-officinalis, tau transgenic}, pubstate = {published}, tppubtype = {article} } Alzheimer's disease is a common tauopathy where fibril formation and aggregates are the hallmark of the disease. Efforts targeting amyloid-beta plaques have succeeded to remove plaques but failed in clinical trials to improve cognition; thus, the current therapeutic strategy is at preventing tau aggregation. Here, we demonstrated that four phenolic diterpenoids and rosmarinic acid inhibit fibrillization. Since, rosmarinic acid was the most active compound, we observe morphological changes in atomic force microscopy images after treatment. Hence, rosmarinic acid leads to a decrease in amide regions I and III, indicating that rosmarinic acid prevents beta-sheet assembly. Molecular docking study inside the steric zipper model of the hexapeptide (306)VQIVYK(311) involved in fibrillization and beta sheet formation, suggests that rosmarinic acid binds to the steric zipper with similar chemical interactions with respect to those observed for orange G, a known pharmacofore for amyloid. |
2016 |
Yempala, T; Cassels, B K Simple and Efficient Synthesis of Various Dibenzofuran Carbaldehydes Artículo de revista Synthetic Communications, 46 (23), pp. 1909-1915, 2016, ISSN: 0039-7911. Resumen | Enlaces | BibTeX | Etiquetas: bond bromo carbaldehydes, cascade, derivatives, design, dibenzofuran efficient evaluation, formation, formylation, furans, methoxy phytoalexins, protocols, stems @article{RN292, title = {Simple and Efficient Synthesis of Various Dibenzofuran Carbaldehydes}, author = { T. Yempala and B.K. Cassels}, url = {/brokenurl#<Go to ISI>://WOS:000388722500006}, doi = {10.1080/00397911.2016.1235201}, issn = {0039-7911}, year = {2016}, date = {2016-01-01}, journal = {Synthetic Communications}, volume = {46}, number = {23}, pages = {1909-1915}, abstract = {We herein report simple and efficient methods for the synthesis of various formyl derivatives of dibenzofuran. The aldehydes reported are prepared in at most three steps and in yields greater than 60% from commercially available dibenzofuran, with one exception where isomers must be separated. The protocols described involve either formylation of previously functionalized dibenzofuran derivatives or the initial introduction of the formyl group and subsequent further functionalization under standard reaction conditions as described. We have also reported an efficient and simple method for the synthesis of keywords methoxydibenzofurans in high yield (65% overall for two steps}, keywords = {bond bromo carbaldehydes, cascade, derivatives, design, dibenzofuran efficient evaluation, formation, formylation, furans, methoxy phytoalexins, protocols, stems}, pubstate = {published}, tppubtype = {article} } We herein report simple and efficient methods for the synthesis of various formyl derivatives of dibenzofuran. The aldehydes reported are prepared in at most three steps and in yields greater than 60% from commercially available dibenzofuran, with one exception where isomers must be separated. The protocols described involve either formylation of previously functionalized dibenzofuran derivatives or the initial introduction of the formyl group and subsequent further functionalization under standard reaction conditions as described. We have also reported an efficient and simple method for the synthesis of keywords methoxydibenzofurans in high yield (65% overall for two steps |
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