RESUMO
In this paper, we investigated the intra-species bacterial quorum sensing at the single cell level using a double droplet trapping system. Escherichia coli transformed to express the quorum sensing receptor protein, LasR, were encapsulated in microdroplets that were positioned adjacent to microdroplets containing the autoinducer, N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL). Functional activation of the LasR protein by diffusion of the OdDHL across the droplet interface was measured by monitoring the expression of green fluorescent protein (GFP) from a LasR-dependent promoter. A threshold concentration of OdDHL was found to induce production of quorum-sensing associated GFP by E. coli. Additionally, we demonstrated that LasR-dependent activation of GFP expression was also initiated when the adjacent droplets contained single E. coli transformed with the OdDHL synthase gene, LasI, representing a simple quorum sensing circuit between two droplets.
Assuntos
Proteínas de Bactérias/metabolismo , Escherichia coli/metabolismo , Técnicas Analíticas Microfluídicas/métodos , Percepção de Quorum , Análise de Célula Única/métodos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Proteínas de Bactérias/genética , Escherichia coli/citologia , Escherichia coli/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Homosserina/análogos & derivados , Homosserina/metabolismo , Técnicas Analíticas Microfluídicas/instrumentação , Microscopia de Fluorescência , Regiões Promotoras Genéticas/genética , Análise de Célula Única/instrumentação , Transativadores/genética , Transativadores/metabolismo , Transformação GenéticaRESUMO
A microfluidic device capable of exploiting the permeability of small molecules through polydimethylsiloxane (PDMS) has been fabricated in order to control the contents of microdroplets stored in storage wells. We demonstrate that protein precipitation and crystallization can be triggered by delivery of ethanol from a reservoir channel, thus controlling the protein solubility in microdroplets. Likewise quorum sensing in bacteria was triggered by delivery of the auto-inducer N-(3-oxododecanoyl)-l-homoserine lactone (OdDHL) through the PDMS membrane of the device.
Assuntos
Dimetilpolisiloxanos/química , Técnicas Analíticas Microfluídicas/métodos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/química , Cristalização , Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Homosserina/análogos & derivados , Homosserina/química , Técnicas Analíticas Microfluídicas/instrumentação , Microscopia de Fluorescência , Permeabilidade , Percepção de Quorum/efeitos dos fármacosRESUMO
Here we present the design, fabrication and operation of a microfluidic device to trap droplets in a large array of droplet pairs in a controlled manner with the aim of studying the transport of small molecules across the resultant surfactant bilayers formed between the droplet pairs.
Assuntos
Técnicas Analíticas Microfluídicas , Microtecnologia/métodos , Movimento (Física) , Tensoativos/química , Difusão , Fluoresceína/química , Corantes Fluorescentes/química , Peróxido de Hidrogênio/química , CinéticaRESUMO
The scope and limitations of a regioselective synthesis of either alpha- or beta-substituted gamma-hydroxybutenolides from 3-furfural and enones are described. The sequence features a Baylis-Hillman reaction followed by singlet oxygen oxidation with use of either an amine base or TBAF as the regioselectivity switches. Structural studies in solution on some of the resulting gamma-hydroxybutenolides are also reported.
Assuntos
Butanóis/síntese química , Oxigênio/química , Butanóis/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , EstereoisomerismoRESUMO
A facile synthesis of alpha-substituted gamma-hydroxybutenolides from 3-furfural was achieved using a Baylis-Hillman reaction followed by singlet oxygen oxidation. The regioselectivity of this conversion was controlled by using TBAF.
Assuntos
4-Butirolactona/análogos & derivados , Química Orgânica/métodos , Fluoretos/química , Furanos/química , Oxigênio Singlete , 4-Butirolactona/química , Catálise , Modelos Químicos , Oxigênio/química , Compostos de Amônio Quaternário/química , Oxigênio Singlete/química , EstereoisomerismoRESUMO
A facile synthesis of beta-functionalized gamma-hydroxybutenolides was achieved using a Baylis-Hillman reaction followed by singlet oxygen oxidation. The conversion from 3-furfural was regio- and diastereoselective. [reaction: see text].