RESUMO
The extracellular matrix is fundamental in order to maintain normal function in many organs such as the blood vessels, heart, liver, or bones. When organs fail or experience injury, tissue engineering and regenerative medicine elicit the production of constructs resembling the native extracellular matrix, supporting organ restoration and function. In this regard, is it possible to optimize structural characteristics of nanofiber scaffolds obtained by the electrospinning technique? This study aimed to produce partially degraded collagen (gelatin) nanofiber scaffolds, using the electrospinning technique, with optimized parameters rendering different morphological characteristics of nanofibers, as well as assessing whether the resulting scaffolds are suitable to integrate primary human endothelial progenitor cells, obtained from peripheral blood with further in vitro cell expansion. After different assay conditions, the best nanofiber morphology was obtained with the following electrospinning parameters: 15 kV, 0.06 mL/h, 1000 rpm and 12 cm needle-to-collector distance, yielding an average nanofiber thickness of 333 ± 130 nm. Nanofiber scaffolds rendered through such electrospinning conditions were suitable for the integration and proliferation of human endothelial progenitor cells.
RESUMO
The effect of exogenous application of jasmonic acid (JA) on the concentration of main terpenes and density of glandular trichomes was investigated in the Mexican oregano, propagated from seeds from 3 localities. JA 1 mM was applied locally and to the whole plant. JA locally applied increased the number of trichomes, with a mean of 20 trichomes more with respect to the controls in plants from Tecomavaca and Zapotitlán Salinas, and significantly increased the thymol concentration by 185% systemically and 255% locally, compared to the control. JA applied to the whole plant decreased the number of trichomes and increased the concentration of caryophyllene from 0.79 to 1.7 mg g-1, and α-caryophyllene from 0.3 to 0.8 mg g-1 in plants from San Rafael with reference to water control. The results suggest a plasticity of morphologic and phytochemical responses, and a potential use of JA to improve phenolic monoterpenes and sesquiterpenes production.
Assuntos
Ciclopentanos/farmacologia , Oxilipinas/farmacologia , Terpenos/análise , Tricomas/efeitos dos fármacos , Verbenaceae/efeitos dos fármacos , Lippia , México , Sesquiterpenos Monocíclicos , Monoterpenos/análise , Origanum/efeitos dos fármacos , Sesquiterpenos Policíclicos/análise , Timol/análiseRESUMO
Species belonging to the genus Populus (poplars) produce a series of defensive proteins in response to insect damage. Proteinase inhibitors, polyphenol oxidases, and chitinases are the most relevant and intensively studied proteins. Most of the knowledge about the relation between these proteins and herbivores has been obtained from studies with chewing insects. Nothing is known about whether phloem-feeder insects such as aphids are able to trigger a comparable response. In the current study, the expression of genes encoding a Kunitz trypsin inhibitor 3 (KTI3), a polyphenol oxidase 1 (PPO1), and a class I chitinase (CHI) was characterized in two poplar hybrids (one resistant hybrid and one susceptible hybrid, to aphids) attacked by the aphid Chaitophorus leucomelas Koch. The expression pattern was analyzed using a semiquantitative reverse transcription-polymerase chain reaction approach. The expression of KTI3 was increased by aphids only in the aphid-susceptible hybrid. Differently, PPO1 expression was increased by aphids in the aphid-resistant hybrid. The expression of CHI was down-regulated by aphids in the susceptible hybrid. This is the first study to report the differential expression of poplar defense genes in response to phloem-feeder insects such as aphids. The findings from the current study suggest that the expression levels of defensive proteins are affected by poplar genotype and by aphid infestation.