A ClpB Chaperone Knockout Mutant of Mesorhizobium ciceri Shows a Delay in the Root Nodulation of Chickpea Plants

Several molecular chaperones are known to be involved in bacteria stress response. To investigate the role of chaperone ClpB in rhizobia stress tolerance as well as in the rhizobiaplant symbiosis process, the clpB gene from a chickpea microsymbiont, strain Mesorhizobium ciceri LMS-1, was identified and a knockout mutant was obtained. The ClpB knockout mutant was tested to several abiotic stresses, showing that it was unable to grow after a heat shock and it was more sensitive to acid shock than the wild-type strain. A plant-growth assay performed to evaluate the symbiotic performance of the clpB mutant showed a higher proportion of ineffective root nodules obtained with the mutant than with the wild-type strain. Nodulation kinetics analysis showed a 6- to 8-day delay in nodule appearance in plants inoculated with the Delta clpB mutant. Analysis of nodC gene expression showed lower levels of transcript in the Delta clpB mutant strain. Analysis of histological sections of nodules formed by the clpB mutant showed that most of the nodules presented a low number of bacteroids. No differences in the root infection abilities of green fluorescent protein tagged clpB mutant and wild-type strains were detected. To our knowledge, this is the first study that presents evidence of the involvement of the chaperone ClpB from rhizobia in the symbiotic nodulation process

Tingimento da poliamida 6.6 com corantes reactivos para lã e algodão após modificação superficial com descarga plasmátca de dupla barreira dieléctrica (DBD)

O tingimento de fibras de poliamida é muito comum com corantes ácidos; entretanto o uso de corantes reativos pode oferecer grandes oportunidades para o desenvolvimento de novos produtos com melhores propriedades como brilho, níveis de solidez,esgotamento, uma maior gama de cores, dentre outras. Tecidos de poliamida 6.6 foram tratados com diferentes dosagens de descarga plasmática obtidas em condições atmosféricas em um protótipo de descarga de dupla barreira SOFTAL/Universidade do Minho. Modificações químicas e físicas na poliamida foram avaliadas, nomeadamente alteração da energia superficial através da medição do ângulo de contato, caracterização da superfície química através da espectroscopia fotoeletrônica de raio X (XPS), foram avaliadas também a rugosidade e a modificação superficial pela microscopia de força atômica (AFM) e Microscopia Eletrônica de Varredura (SEM). Ótimos resultados foram obtidos para o tingimento com corantes reativos na poliamida após o tratamento plasmático, com a formação de ligações covalentes entre o corante e a fibra. Os efeitos químicos e físicos da descarga plasmática contribuíram para os excelentes resultados obtidos no rendimento e no nível de solidez conseguidos no processo de tingimento. Estes promissores resultados significam menos corantes nos efluentes, menos tempo para a realização do processo de tingimento, maior satisfação dos consumidores devido aos melhores níveis de solidez e a possibilidade de obter cores mais intensas com tingimentos com corantes reativos em poliamida

Tingimento da poliamida 6.6 com corantes reactivos para lã e algodão após modificação superficial com descarga plasmática de Dupla Barreira Dieléctrica (DBD)

O tingimento de fibras de poliamida é muito comum com corantes ácidos; entretanto o uso de corantes reativos pode oferecer grandes oportunidades para o desenvolvimento de novos produtos com melhores propriedades como brilho, níveis de solidez,esgotamento, uma maior gama de cores, dentre outras. Tecidos de poliamida 6.6 foram tratados com diferentes dosagens de descarga plasmática obtidas em condições atmosféricas em um protótipo de descarga de dupla barreira SOFTAL/Universidade do Minho. Modificações químicas e físicas na poliamida foram avaliadas, nomeadamente alteração da energia superficial através da medição do ângulo de contato, caracterização da superfície química através da espectroscopia fotoeletrônica de raio X (XPS), foram avaliadas também a rugosidade e a modificação superficial pela microscopia de força atômica (AFM) e Microscopia Eletrônica de Varredura (SEM). Ótimos resultados foram obtidos para o tingimento com corantes reativos na poliamida após o tratamento plasmático, com a formação de ligações covalentes entre o corante e a fibra. Os efeitos químicos e físicos da descarga plasmática contribuíram para os excelentes resultados obtidos no rendimento e no nível de solidez conseguidos no processo de tingimento. Estes promissores resultados significam menos corantes nos efluentes, menos tempo para a realização do processo de tingimento, maior satisfação dos consumidores devido aos melhores níveis de solidez e a possibilidade de obter cores mais intensas com tingimentos com corantes reativos em poliamida.Dyeing of polyamide fibers is very common with acid dyes; however the use of the reactive dyes can give the best opportunities for development the new products with the most desirable properties like brightness, paler colors, good exhaustion and washing fastness levels. Chemical and physical effects of plasmatic discharge both contribute to excellent results obtained in yield, leveling and fastness of reactive and acid dyeing. Polyamide 6.6 fabrics were treated with different dosages of plasmatic discharge obtained at atmospheric conditions in DBD prototype SOFTAL/University of Minho. Chemical and physical modifications in polyamide were evaluated, namely surface energy modification by contact angle measurement, chemical surface characterization by X-Photon Spectroscopy (XPS). Besides, were evaluated the roughness and surface changes by Atomic Force Microscopy (AFM) and Scanning Electronic Microscopy (SEM). These promising results mean less dyes in effluents, less time for dyeing processes, more consumer’s satisfaction regarding fastness of dyeing, the possibility to extend reactive dyeing to more intense colors in polyamid

Reuse of effluent from dyeing process of polyamide fibers modified by double barrier discharge (DBD) plasma

Published online: 27 Feb 2015Low-temperature plasma technology becomes more and more attractive compared with traditional wet processes in textile preparation and finishing due to its high efficiency and low environmental impact. The objective of this study was to investigate the influence of dielectric barrier discharge plasma treatment on the trichromic dyeing process of polyamide 6.6 (PA66) and the reuse of the generated effluents for new dyeing processes. Chemical and physical characterization of the plasma-treated polyamide fibers was studied by means of static and dynamic contact angle, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy micrographs, and atomic force microscopy (AFM). Plasma treatment greatly increases the hydrophilicity and adhesion of PA66, due to the increase of polar groups and roughness on the fibers surface as confirmed by XPS and AFM. The kinetics of dyeing is quicker but leveled with high rubbing, light, and washing fastness quality. The reuse of the effluent obtained after dyeing of the plasma-treated fabrics showed excellent results of reproducibility, uniformity, and washing fastness. It was possible to reproduce the standard color for three dyeing cycles using the same effluent reducing the effluent load with a significant diminution in costs and environmental impact.Andrea Zille (C2011- UMINHO-2C2T-01) acknowledges funding from Programa Compromisso para a Ciencia 2008, Portugal

Plasma technology applied in textile industry

Plasma technology applied to textiles is a dry, environmentally and worker friendly method to achieve surface alteration without modifying the bulk properties of different materials. In particular, atmospheric non-thermal plasmas are appropriate because most textile materials are heat sensitive polymers and applicable in a continuous processes. In the last years plasma technology has become a very active, high growth research field, assuming a great importance among all available material surface modifications in textile industry. The main objective of this work is to present an update on the current state of art relating plasma technologies applied to textile industry. The main effects obtained by the application of plasma discharge and all the textile production chain such as: desizing, mercerization, dyeing, printing, composite and finishing will be superficially discussed