Repositorio INDICASAT AIP
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Bastimolide B, an Antimalarial 24-Membered Marine Macrolide Possessing a tert-Butyl Group
Full text linkWe reported previously the discovery of the potent antimalarial 40-membered macrolide bastimolide A (1) from the tropical marine cyanobacterium Okeania hirsute. Continued investigation has led to the discovery of a new analogue, bastimolide B (2), a 24-membered polyhydroxy macrolide with a long aliphatic chain and unique terminal tertbutyl group. Its complete structure was determined by a combination of extensive spectroscopic methods and comparative analysis of its methanolysis products with those of bastimolide A. A methanolysis mechanism for bastimolide A is proposed, and one unexpected isomerization product of the C2−C3 double bond, 2-(E)-bastimolide A (3), was obtained. Bastimolide B (2) showed strong antimalarial activity against chloroquine-sensitive Plasmodium falciparum strain HB3. A preliminary investigation of the structure−activity relationship based on six analogues revealed the importance of the double bond as well as the 1,3-diol and 1,3,5-triol functionalities.We reported previously the discovery of the potent antimalarial 40-membered macrolide bastimolide A (1) from the tropical marine cyanobacterium Okeania hirsute. Continued investigation has led to the discovery of a new analogue, bastimolide B (2), a 24-membered polyhydroxy macrolide with a long aliphatic chain and unique terminal tertbutyl group. Its complete structure was determined by a combination of extensive spectroscopic methods and comparative analysis of its methanolysis products with those of bastimolide A. A methanolysis mechanism for bastimolide A is proposed, and one unexpected isomerization product of the C2−C3 double bond, 2-(E)-bastimolide A (3), was obtained. Bastimolide B (2) showed strong antimalarial activity against chloroquine-sensitive Plasmodium falciparum strain HB3. A preliminary investigation of the structure−activity relationship based on six analogues revealed the importance of the double bond as well as the 1,3-diol and 1,3,5-triol functionalities
Effect of Post Weld Heat Treatments on the Elevated Temperature Mechanical Properties of Ti6Al4V Friction Welds
Full text linkThe {\alpha}+\b {eta} titanium alloy (Ti6Al4V) has been successfully joined using rotary friction welding. To investigate the influence of post weld heat treatments on the microstructure and mechanical properties of the welds, the weld joints were heat treated in {\alpha}+\b {eta} and\b {eta} regions, followed by air cooling and furnace cooling. Subsequent to heat treatment, the specimens were subjected to stress relieving treatment. The heat treatment temperatures were selected keeping in view the beta transus temperature of the alloy. Mechanical properties of the welds are evaluated in the as-welded and post weld heat treated conditions at the working temperature of this alloy. The results reported are an average of the values obtained from three tests carried out at a given set of condition. Joints produced exhibited better mechanical properties when compared to the parent metal. Coarse transgranular microstructure and coarse grains in general exhibit better creep and stress rupture properties, while finer microstructures exhibit better tensile strengthsThe {\alpha}+\b {eta} titanium alloy (Ti6Al4V) has been successfully joined using rotary friction welding. To investigate the influence of post weld heat treatments on the microstructure and mechanical properties of the welds, the weld joints were heat treated in {\alpha}+\b {eta} and\b {eta} regions, followed by air cooling and furnace cooling. Subsequent to heat treatment, the specimens were subjected to stress relieving treatment. The heat treatment temperatures were selected keeping in view the beta transus temperature of the alloy. Mechanical properties of the welds are evaluated in the as-welded and post weld heat treated conditions at the working temperature of this alloy. The results reported are an average of the values obtained from three tests carried out at a given set of condition. Joints produced exhibited better mechanical properties when compared to the parent metal. Coarse transgranular microstructure and coarse grains in general exhibit better creep and stress rupture properties, while finer microstructures exhibit better tensile strength
Mycobacterial Lipids Induce Calcium Mobilization and Degranulation of Mast Cells
Full text linkCells and culture conditions. Murine MCs from line C1.MC/C57.1 (C57 MC) were kindly provided by Dr. Stephen Galli (Stanford University) and cultured in Dulbecco’s modified Eagle’s medium according to standard methods (9). M. tuberculosis lipid extracts. The bacterial lipid fractions extracted from H37Rv M. tuberculosis, including total lipids (T-L, NR-14837), insoluble lipids (I-L, NR-14843), soluble lipids (S-L, NR-14842), M. leprae, phenolic glycolipid I (PGL-I, NR-19342), and M. tuberculosis phosphatidylinositol mannoside 6 (PIM6, NR-14847), were obtained from BEI Resources. Purified bovine heart L-a-phosphatidylcholine (PC, 840052C) and cardiolipin (CL, 840012C) were obtained from Avanti Polar Lipids. All M. tuberculosis lipid extracts were resuspended according to the manufacturer’s recommendations.Cells and culture conditions. Murine MCs from line C1.MC/C57.1 (C57 MC) were kindly provided by Dr. Stephen Galli (Stanford University) and cultured in Dulbecco’s modified Eagle’s medium according to standard methods (9). M. tuberculosis lipid extracts. The bacterial lipid fractions extracted from H37Rv M. tuberculosis, including total lipids (T-L, NR-14837), insoluble lipids (I-L, NR-14843), soluble lipids (S-L, NR-14842), M. leprae, phenolic glycolipid I (PGL-I, NR-19342), and M. tuberculosis phosphatidylinositol mannoside 6 (PIM6, NR-14847), were obtained from BEI Resources. Purified bovine heart L-a-phosphatidylcholine (PC, 840052C) and cardiolipin (CL, 840012C) were obtained from Avanti Polar Lipids. All M. tuberculosis lipid extracts were resuspended according to the manufacturer’s recommendations
Diversity and Allelopathic Potential of Weeds among Panamanian Coffee Crops
Full text linkWorldwide, coffee is one of the most highly consumed and produced crops. Coffee production is a significant activity in the Panamanian economy, mainly in rural communities and among indigenous groups in the Chiriquí province highlands. Weeds growing alongside coffee plants can provoke considerable economic losses for producers by interfering with the growth, development and yield of coffee crop in cultivated areas. Designing an effective program to control weeds depends on identifying the different species found in the coffee plantations. The objective of this study was to assess the biological diversity and negative allelopathic potential of weeds in a coffee field to generate enough information that would better allow farmers to control them. As a result, we identified forty-two different species of weeds in all sampling transects within the study area. Emilia sonchifolia and Impatiens walleriana were the most abundant. In respect to phytotoxic activity, Emilia sonchifolia and Hyptis capitata showed the highest activity against the seed germination of dicotyledonous species Amaranthus hypochondriacus, exhibiting IC50 values of 160 and 178 µg mL−1 , respectively. Finally, we proceeded to evaluate the organic extracts of two coffee weeds in a panel of bioassays to demonstrate to the farmers that weeds may also have useful applications for human health. Borreria verticillata showed antimalaric activity while Blechum pyramidatum displayed inhibition of the α-glucosidase enzyme. These results allow us to propose a rational and systematic management of coffee weedsWorldwide, coffee is one of the most highly consumed and produced crops. Coffee production is a significant activity in the Panamanian economy, mainly in rural communities and among indigenous groups in the Chiriquí province highlands. Weeds growing alongside coffee plants can provoke considerable economic losses for producers by interfering with the growth, development and yield of coffee crop in cultivated areas. Designing an effective program to control weeds depends on identifying the different species found in the coffee plantations. The objective of this study was to assess the biological diversity and negative allelopathic potential of weeds in a coffee field to generate enough information that would better allow farmers to control them. As a result, we identified forty-two different species of weeds in all sampling transects within the study area. Emilia sonchifolia and Impatiens walleriana were the most abundant. In respect to phytotoxic activity, Emilia sonchifolia and Hyptis capitata showed the highest activity against the seed germination of dicotyledonous species Amaranthus hypochondriacus, exhibiting IC50 values of 160 and 178 µg mL−1 , respectively. Finally, we proceeded to evaluate the organic extracts of two coffee weeds in a panel of bioassays to demonstrate to the farmers that weeds may also have useful applications for human health. Borreria verticillata showed antimalaric activity while Blechum pyramidatum displayed inhibition of the α-glucosidase enzyme. These results allow us to propose a rational and systematic management of coffee weed
Disturbance and mosquito diversity in the lowland tropical rainforest of central Panama
Full text linkThe Intermediate Disturbance Hypothesis (IDH) is well-known in ecology providing an explanation for the role of disturbance in the coexistence of climax and colonist species. Here, we used the IDH as a framework to describe the role of forest disturbance in shaping the mosquito community structure, and to identify the ecological processes that increase the emergence of vector-borne disease. Mosquitoes were collected in central Panama at immature stages along linear transects in colonising, mixed and climax forest habitats, representing diferent levels of disturbance. Species were identifed taxonomically and classifed into functional categories (i.e., colonist, climax, disturbance-generalist, and rare). Using the Huisman-Olf-Fresco multi-model selection approach, IDH testing was done. We did not detect a unimodal relationship between species diversity and forest disturbance expected under the IDH; instead diversity peaked in old-growth forests. Habitat complexity and constraints are two mechanisms proposed to explain this alternative postulate. Moreover, colonist mosquito species were more likely to be involved in or capable of pathogen transmission than climax species. Vector species occurrence decreased notably in undisturbed forest settings. Old-growth forest conservation in tropical rainforests is therefore a highly-recommended solution for preventing new outbreaks of arboviral and parasitic diseases in anthropic environments.The Intermediate Disturbance Hypothesis (IDH) is well-known in ecology providing an explanation for the role of disturbance in the coexistence of climax and colonist species. Here, we used the IDH as a framework to describe the role of forest disturbance in shaping the mosquito community structure, and to identify the ecological processes that increase the emergence of vector-borne disease. Mosquitoes were collected in central Panama at immature stages along linear transects in colonising, mixed and climax forest habitats, representing diferent levels of disturbance. Species were identifed taxonomically and classifed into functional categories (i.e., colonist, climax, disturbance-generalist, and rare). Using the Huisman-Olf-Fresco multi-model selection approach, IDH testing was done. We did not detect a unimodal relationship between species diversity and forest disturbance expected under the IDH; instead diversity peaked in old-growth forests. Habitat complexity and constraints are two mechanisms proposed to explain this alternative postulate. Moreover, colonist mosquito species were more likely to be involved in or capable of pathogen transmission than climax species. Vector species occurrence decreased notably in undisturbed forest settings. Old-growth forest conservation in tropical rainforests is therefore a highly-recommended solution for preventing new outbreaks of arboviral and parasitic diseases in anthropic environments
Green Synthesis of Silver Nanoparticles using two Apocyanaceae plants and Screening for their Catalytic activity
Full text linkThe catalytic activity of biosynthesized silver nanoparticles (AgNPs) gained an importance in removal of synthetic dyes from waste water released form textile industries. In this study aqueous leaf extract of Cascabela thevetia and Wrightia tomentosa were used to synthesize silver nanoparticles. Further the catalytic activity of newly synthesized particles in reducing 4-Nitrophenol, Methylene blue, Methyl orange and Methyl red using NaBH4 was screened. It was observed that the respective amalgamated solutions of AgNO3 and leaf extract turned reddish brown in colour after 48 hours incubation. The formation of AgNPs from C. thevetia and W.tomentosa were conformed by absorption maximum at 443.07nm and 440.05 nm in UV-Visible analysis. The absorption maxima results in UV-Vsible analysis of respective dyes clearly indicate total degradation by NaBH4 and the AgNPs of both plants have exhibited remarkable catalytic activity in dye reduction reactions.The catalytic activity of biosynthesized silver nanoparticles (AgNPs) gained an importance in removal of synthetic dyes from waste water released form textile industries. In this study aqueous leaf extract of Cascabela thevetia and Wrightia tomentosa were used to synthesize silver nanoparticles. Further the catalytic activity of newly synthesized particles in reducing 4-Nitrophenol, Methylene blue, Methyl orange and Methyl red using NaBH4 was screened. It was observed that the respective amalgamated solutions of AgNO3 and leaf extract turned reddish brown in colour after 48 hours incubation. The formation of AgNPs from C. thevetia and W.tomentosa were conformed by absorption maximum at 443.07nm and 440.05 nm in UV-Visible analysis. The absorption maxima results in UV-Vsible analysis of respective dyes clearly indicate total degradation by NaBH4 and the AgNPs of both plants have exhibited remarkable catalytic activity in dye reduction reactions
Exposure to the leaf litter microbiome of healthy adults protects seedlings from pathogen damage
Full text linkIt is increasingly recognized that microbiota affect host health and physiology. However, it is unclear what factors shape microbiome community assembly in nature, and how microbiome assembly can be manipulated to improve host health. All plant leaves host foliar endophytic fungi, which make up a diverse, environmentally acquired fungal microbiota. Here, we experimentally manipulated assembly of the cacao tree (Theobroma cacao) fungal microbiome in nature and tested the effect of assembly outcome on host health. Using next-generation sequencing, as well as culture-based methods coupled with Sanger sequencing, we found that manipulating leaf litter exposure and location within the forest canopy significantly altered microbiome composition in cacao. Exposing cacao seedlings to leaf litter from healthy conspecific adults enriched the seedling microbiome with Colletotrichum tropicale, a fungal endophyte known to enhance pathogen resistance of cacao seedlings by upregulating host defensive pathways. As a result, seedlings exposed to healthy conspecific litter experienced reduced pathogen damage. Our results link processes that affect the assembly and composition of microbiome communities to their functional consequences for host success, and have broad implications for understanding plant–microbe interactions. Deliberate manipulation of the plant– fungal microbiome also has potentially important applications for cacao production and other agricultural systems in generalIt is increasingly recognized that microbiota affect host health and physiology. However, it is unclear what factors shape microbiome community assembly in nature, and how microbiome assembly can be manipulated to improve host health. All plant leaves host foliar endophytic fungi, which make up a diverse, environmentally acquired fungal microbiota. Here, we experimentally manipulated assembly of the cacao tree (Theobroma cacao) fungal microbiome in nature and tested the effect of assembly outcome on host health. Using next-generation sequencing, as well as culture-based methods coupled with Sanger sequencing, we found that manipulating leaf litter exposure and location within the forest canopy significantly altered microbiome composition in cacao. Exposing cacao seedlings to leaf litter from healthy conspecific adults enriched the seedling microbiome with Colletotrichum tropicale, a fungal endophyte known to enhance pathogen resistance of cacao seedlings by upregulating host defensive pathways. As a result, seedlings exposed to healthy conspecific litter experienced reduced pathogen damage. Our results link processes that affect the assembly and composition of microbiome communities to their functional consequences for host success, and have broad implications for understanding plant–microbe interactions. Deliberate manipulation of the plant– fungal microbiome also has potentially important applications for cacao production and other agricultural systems in genera
Imaging mass spectrometry and MS/MS molecular networking reveals chemical interactions among cuticular bacteria and pathogenic fungi associated with fungus-growing ants
Full text linkThe fungus-growing ant-microbe symbiosis is an ideal system to study chemistry-based microbial interactions due to the wealth of microbial interactions described, and the lack of information on the molecules involved therein. In this study, we employed a combination of MALDI imaging mass spectrometry (MALDI-IMS) and MS/MS molecular networking to study chemistry-based microbial interactions in this system. MALDI IMS was used to visualize the distribution of antimicrobials at the inhibition zone between bacteria associated to the ant Acromyrmex echinatior and the fungal pathogen Escovopsis sp. MS/MS molecular networking was used for the dereplication of compounds found at the inhibition zones. We identified the antibiotics actinomycins D, X2 and X0β, produced by the bacterium Streptomyces CBR38; and the macrolides elaiophylin, efomycin A and efomycin G, produced by the bacterium Streptomyces CBR53.These metabolites were found at the inhibition zones using MALDI IMS and were identified using MS/MS molecular networking. Additionally, three shearinines D, F, and J produced by the fungal pathogen Escovopsis TZ49 were detected. This is the first report of elaiophylins, actinomycin X0β and shearinines in the fungus-growing ant symbiotic system. These results suggest a secondary prophylactic use of these antibiotics by A. echinatior because of their permanent production by the bacteria.The fungus-growing ant-microbe symbiosis is an ideal system to study chemistry-based microbial interactions due to the wealth of microbial interactions described, and the lack of information on the molecules involved therein. In this study, we employed a combination of MALDI imaging mass spectrometry (MALDI-IMS) and MS/MS molecular networking to study chemistry-based microbial interactions in this system. MALDI IMS was used to visualize the distribution of antimicrobials at the inhibition zone between bacteria associated to the ant Acromyrmex echinatior and the fungal pathogen Escovopsis sp. MS/MS molecular networking was used for the dereplication of compounds found at the inhibition zones. We identified the antibiotics actinomycins D, X2 and X0β, produced by the bacterium Streptomyces CBR38; and the macrolides elaiophylin, efomycin A and efomycin G, produced by the bacterium Streptomyces CBR53.These metabolites were found at the inhibition zones using MALDI IMS and were identified using MS/MS molecular networking. Additionally, three shearinines D, F, and J produced by the fungal pathogen Escovopsis TZ49 were detected. This is the first report of elaiophylins, actinomycin X0β and shearinines in the fungus-growing ant symbiotic system. These results suggest a secondary prophylactic use of these antibiotics by A. echinatior because of their permanent production by the bacteria
Dudawalamides A−D, Antiparasitic Cyclic Depsipeptides from the Marine Cyanobacterium Moorea producens
Full text linkHPLC. DudA family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A−D (1−4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A−D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey’s analysis, chiral-phase GCMS, and chiral-phase awalamides A−D possess a broad spectrum of antiparasitic activity with minimal mammalian cell cytotoxicity. Comparative analysis of the Dhoya-containing class of lipopeptides reveals intriguing structure−activity relationship features of these NRPS−PKS-derived metabolites and their derivatives.HPLC. DudA family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A−D (1−4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A−D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey’s analysis, chiral-phase GCMS, and chiral-phase awalamides A−D possess a broad spectrum of antiparasitic activity with minimal mammalian cell cytotoxicity. Comparative analysis of the Dhoya-containing class of lipopeptides reveals intriguing structure−activity relationship features of these NRPS−PKS-derived metabolites and their derivatives
Utilidad de la escala de depresión geriátrica en adultos mayores atendidos en el servicio de geriatría de la caja de seguro social
Full text linkINTRODUCCIÓN. La depresión en pacientes geriátricos consiste de síntomas y características clínicas específicas que representan una condición grave que predispone a alteraciones en la funcionalidad de esta población. La Escala de Depresión Geriátrica (GDS, por su sigla en inglés), es un instrumento de tamizaje breve y de fácil aplicación, ampliamente utilizado en la clínica y la investigación para detectar síntomas depresivos. OBJETIVO. Analizar la utilidad de la GDS para detectar síntomas depresivos clínicamente relevantes en adultos mayores que acuden a la consulta externa de Geriatría del Complejo Hospitalario Dr. Arnulfo Arias Madrid (C.H.Dr.A.A.M.). METODOLOGÍA. Se realizó un estudio descriptivo de corte transversal. Se seleccionaron adultos mayores de 65 años o más del estudio Panama Aging Research Initiative (PARI). Un total de 423 participantes fueron reclutados en el estudio. De éstos, 144 participantes completaron la evaluación psiquiátrica y la GDS30 en su versión en español. RESULTADOS. El 16.7% de los participantes recibieron diagnóstico de depresión luego de la entrevista psiquiátrica. El valor predictivo positivo de la GDS-30 fue de 44.4% y el valor predictivo negativo fue de 92.6%. CONCLUSIÓN. Por el alto valor predictivo negativo de la GDS, se recomienda su uso para descartar casos en los que no existe depresión, aplicándolo como instrumento de tamizaje en los controles de salud de adultos mayores.INTRODUCCIÓN. La depresión en pacientes geriátricos consiste de síntomas y características clínicas específicas que representan una condición grave que predispone a alteraciones en la funcionalidad de esta población. La Escala de Depresión Geriátrica (GDS, por su sigla en inglés), es un instrumento de tamizaje breve y de fácil aplicación, ampliamente utilizado en la clínica y la investigación para detectar síntomas depresivos. OBJETIVO. Analizar la utilidad de la GDS para detectar síntomas depresivos clínicamente relevantes en adultos mayores que acuden a la consulta externa de Geriatría del Complejo Hospitalario Dr. Arnulfo Arias Madrid (C.H.Dr.A.A.M.). METODOLOGÍA. Se realizó un estudio descriptivo de corte transversal. Se seleccionaron adultos mayores de 65 años o más del estudio Panama Aging Research Initiative (PARI). Un total de 423 participantes fueron reclutados en el estudio. De éstos, 144 participantes completaron la evaluación psiquiátrica y la GDS30 en su versión en español. RESULTADOS. El 16.7% de los participantes recibieron diagnóstico de depresión luego de la entrevista psiquiátrica. El valor predictivo positivo de la GDS-30 fue de 44.4% y el valor predictivo negativo fue de 92.6%. CONCLUSIÓN. Por el alto valor predictivo negativo de la GDS, se recomienda su uso para descartar casos en los que no existe depresión, aplicándolo como instrumento de tamizaje en los controles de salud de adultos mayores