RESUMEN
Plant growth-promoting rhizobacteria (PGPR) can promote plant growth and development with several beneficial effects, especially in challenging environmental conditions, such as the presence of toxic contaminants. In this study, 49 isolates obtained from Trifolium sp. nodules growing on a Pb/Zn mine site were characterized for PGP traits including siderophores production, phosphate solubilization, extracellular enzymes production, and antifungal activity. The isolates were also screened for their ability to grow at increasing concentrations of NaCl and heavy metals, including lead, zinc, cobalt, copper, nickel, cadmium, and chromium. The findings of our study indicated that isolates Cupriavidus paucula RSCup01-RSCup08, Providencia rettgeri RSPro01, Pseudomonas putida RSPs01, Pseudomonas thivervalensis RSPs03-RSPs09, and Acinetobacter beijerinckii RSAci01 showed several key traits crucial for promoting plant growth, thus demonstrating the greatest potential. Most isolates displayed resistance to salt and heavy metals. Notably, Staphylococcus xylosus RSSta01, Pseudomonas sp. RSPs02, Micrococcus yunnanensis RSMicc01, and Kocuria dechangensis RSKoc01 demonstrated a significant capacity to grow at salt concentrations ranging from 10 to 20%, and isolates including Cupravidus paucula RSCup01-RSCup08 exhibited resistance to high levels of heavy metals, up to 1300 mg/L Pb++, 1200 mg/L Zn++, 1000 mg/L Ni++, 1000 mg/L Cd++, 500 mg/L Cu++, 400 mg/L Co++, and 50 mg/L CrVI+. Additionally, the analysis revealed that metal-resistant genes pbrA, czcD, and nccA were exclusively detected in the Cupriavidus paucula RSCup01 strain. The results of this study provide insights into the potential of plant growth-promoting rhizobacteria strains that might be used as inoculants to improve phytoremediation in heavy metal-contaminated soils.
Asunto(s)
Metales Pesados , Trifolium , Plomo , Monitoreo del Ambiente , Metales Pesados/toxicidad , Zinc , Cloruro de SodioRESUMEN
High concentrations of heavy metals in mine soil disturb the interactions between legumes and microorganisms leading to select strains adapted to these specific conditions. In this work, we analyzed the diversity of fifty strains isolated from Trifolium sp. nodules growing on Pb-Zn mine soil, in the Northeastern of Algeria and highlighted their potential symbiotic traits. The phylogeny of the 16S rRNA gene sequences revealed a high bacterial diversity with a predominance of non-rhizobial endophytes. The identified isolates belong to the thirteen following genera Cupriavidus, Pseudomonas, Bacillus, Acinetobacter, Enterobacter, Roseomonas, Paracoccus, Frondihabitans, Microbacterium, Kocuria, Providencia, Micrococcus and Staphylococcus. Regarding rhizobial strains, only isolates affiliated to Rhizobium genus were obtained. The symbiotic gene nodC and the nitrogen fixation gene nifH present showed that Rhizobium isolates belonged to the symbiovar trifolii. In addition to bacterial, one yeast strain was isolated and identified as Rhodotorula mucilaginosa by sequencing the internal transcribed spacer (ITS) region.
Asunto(s)
Biodiversidad , Endófitos , Plomo , Rhizobium , Trifolium , Zinc , Argelia , Endófitos/clasificación , Endófitos/efectos de los fármacos , Endófitos/genética , Contaminantes Ambientales/toxicidad , Plomo/toxicidad , Minería , Filogenia , ARN Ribosómico 16S/genética , Rhizobium/clasificación , Rhizobium/efectos de los fármacos , Rhizobium/genética , Rhodotorula/genética , Rhodotorula/aislamiento & purificación , Nódulos de las Raíces de las Plantas/microbiología , Simbiosis , Trifolium/microbiología , Zinc/toxicidadRESUMEN
AIM: This paper reports on a study conducted to describe family nurse practitioners' perceptions towards and participation in pharmaceutical marketing and to explore the relationships among related variables. BACKGROUND: The pharmaceutical industry's intense global marketing strategies have resulted in widespread concern in healthcare professionals and professional groups, sectors of the public in many countries, and in the World Health Organization. Research on healthcare providers' participation in pharmaceutical marketing indicates that these relationships are conflicts of interests and compromise healthcare providers' prescribing practices and trust. Nursing, as a discipline, appears to be slow to address the impact of pharmaceutical marketing on nursing practice. METHOD: Questionnaires about perceptions and participation in pharmaceutical marketing were completed by a random sample of 84 licensed family nurse practitioners in the United States of America in 2007. FINDINGS: Family nurse practitioners viewed pharmaceutical company marketing uncritically as educational and beneficial. They also perceived other providers but not themselves as influenced by pharmaceutical marketing. The findings supported those found in previous research with nurses and physicians. CONCLUSION: Lack of education, participation in marketing and psychological and social responses may impede family nurse practitioners' ability to respond critically and appropriately to marketing strategies and the conflict of interest it creates.