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In the present study, silver nanoparticles (AgNPs) were biosynthesized using the supernatant and the intracellular extract of Cupriavidus necator, Bacillus megaterium, and Bacillus subtilis. The characterization of the AgNPs was carried out using UV-Vis spectroscopy, FTIR, DLS and TEM. Resazurin microtiter-plate assay was used to determine the antimicrobial action of AgNPs against Escherichia coli. UV-Visible spectra showed peaks between 414 and 460 nm. TEM analysis revealed that the synthesized AgNPs showed mostly spherical shapes. DLS results determined sizes from 20.8 to 118.4 nm. The highest antimicrobial activity was obtained with the AgNPs synthesized with supernatant rather than those using the intracellular extract. Therefore, it was determined that the bacterial species, temperature, pH, and type of extract (supernatant or intracellular) influence the biosynthesis. This synthesis thus offers a simple, environmentally friendly, and low-cost method for the production of AgNPs, which can be used as antibacterial agents.

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The symbiotic N2-fixation process in the legume-rhizobia interaction is relevant for sustainable agriculture. The characterization of symbiotic mutants, mainly in model legumes, has been instrumental for the discovery of symbiotic genes, but similar studies in crop legumes are scant. To isolate and characterize common bean (Phaseolus vulgaris) symbiotic mutants, an ethyl methanesulphonate-induced mutant population from the BAT 93 genotype was analyzed. Our initial screening of Rhizobium etli CE3-inoculated mutant plants revealed different alterations in nodulation. We proceeded with the characterization of three non-nodulating (nnod), apparently monogenic/recessive mutants: nnod(1895), nnod(2353) and nnod(2114). Their reduced growth in a symbiotic condition was restored when the nitrate was added. A similar nnod phenotype was observed upon inoculation with other efficient rhizobia species. A microscopic analysis revealed a different impairment for each mutant in an early symbiotic step. nnod(1895) formed decreased root hair curling but had increased non-effective root hair deformation and no rhizobia infection. nnod(2353) produced normal root hair curling and rhizobia entrapment to form infection chambers, but the development of the latter was blocked. nnod(2114) formed infection threads that did not elongate and thus did not reach the root cortex level; it occasionally formed non-infected pseudo-nodules. The current research is aimed at mapping the responsible mutated gene for a better understanding of SNF in this critical food crop.

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Objetivo: Evaluar los resultados clínicos y radiográficos en pacientes sometidos a artroplastia unicompartimental de rodilla, así como la tasa de complicaciones y la supervivencia del implante. Materiales y Métodos: Estudio descriptivo retrospectivo de 68 pacientes consecutivos (70 rodillas) sometidos a artroplastia unicompartimental de rodilla entre 2013 y 2020, con un seguimiento medio de 57.7 meses (rango 24-105) y una media de la edad de 61 años (rango 34-79). El 46,5% eran hombres. El índice de masa corporal medio era de 29,9 (rango 20-39). El diagnóstico más frecuente fue la artrosis del compartimento femorotibial medial con un varo <7°. Los resultados se evaluaron con la escala analógica visual para dolor y el Knee Society Score (KSS). Se evaluó la incidencia de complicaciones y la tasa de supervivencia del implante. Resultados: La disminución media en la escala analógica visual para dolor fue de 4,4 ± 1,9. Las puntuaciones medias posoperatorias en las escalas funcional y clínica del KSS fueron de 77,4 ± 13,7 y 70,2 ± 17,7, respectivamente. La tasa de complicaciones posquirúrgicas fue del 7% (5 casos). La tasa de reintervención quirúrgica fue del 15,5% (11 pacientes): nueve casos por persistencia del dolor, uno por rigidez articular y otro por aflojamiento aséptico. Conclusiones: La artroplastia unicompartimental de rodilla es una opción terapéutica eficaz para pacientes con gonartrosis unicompartimental de rodilla; se logran buenos resultados clínicos con una aceptable tasa de complicaciones; sin embargo, la tasa de revisión del implante es considerable. Nivel de Evidencia: IV

Objective: To assess the clinical and radiological outcomes of patients who underwent a unicompartmental knee arthroplasty (UKA), as well as the complication rate and implant survival. Materials and Methods: We present a retrospective descriptive study of 68 consecutive patients (70 knees) who underwent UKA between 2013 and 2020, with an average follow-up of 57.7 mon-ths (range 24-105) and an average age of 61 years (range 34-79). 46.5% of the patients were male. The average BMI was 29.9 (range 20-39). The most frequent etiology was osteoarthritis of the medial femorotibial compartment with a varus <7°. To assess the outcomes, the visual analog scale (VAS) for pain and the Knee Society Score (KSS) were used. The complication and implant survival rates were evaluated. Results: The average decrease in the VAS pain scale was 4.4±1.9. The average score on the postoperative KSS functional and clinical scales were 77.4±13.7 and 70.2±17.7, respectively. The postoperative complication rate was 7% (5 cases). The surgical reoperation rate was 15.5% (11 patients): nine cases for persistent pain, one case for joint stiffness, and one case for aseptic loosening. Conclusions: UKA is an effective therapeutic option for patients with unicompartmental knee osteoarthritis, providing good clinical results with an acceptable rate of complications; however, it provides a considerable implant revision rate. Level of Evidence: IV

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Plants MADS-domain/AGL proteins constitute a large transcription factor (TF) family that controls the development of almost every plant organ. We performed a phylogeny of (ca. 500) MADS-domain proteins from Arabidopsis and four legume species. We identified clades with Arabidopsis MADS-domain proteins known to participate in root development that grouped legume MADS-proteins with similar high expression in roots and nodules. In this work, we analyzed the role of AGL transcription factors in the common bean (Phaseolus vulgaris) - Rhizobium etli N-fixing symbiosis. Sixteen P. vulgaris AGL genes (PvAGL), out of 93 family members, are expressed - at different levels - in roots and nodules. From there, we selected the PvAGL gene denominated PvFUL-like for overexpression or silencing in composite plants, with transgenic roots and nodules, that were used for phenotypic analysis upon inoculation with Rhizobium etli. Because of sequence identity in the DNA sequence used for RNAi-FUL-like construct, roots, and nodules expressing this construct -referred to as RNAi_AGL- showed lower expression of other five PvAGL genes highly expressed in roots/nodules. Contrasting with PvFUL-like overexpressing plants, rhizobia-inoculated plants expressing the RNAi_AGL silencing construct presented affection in the generation and growth of transgenic roots from composite plants, both under non-inoculated or rhizobia-inoculated condition. Furthermore, the rhizobia-inoculated plants showed decreased rhizobial infection concomitant with the lower expression level of early symbiotic genes and increased number of small, ineffective nodules that indicate an alteration in the autoregulation of the nodulation symbiotic process. We propose that the positive effects of PvAGL TF in the rhizobia symbiotic processes result from its potential interplay with NIN, the master symbiotic TF regulator, that showed a CArG-box consensus DNA sequence recognized for DNA binding of AGL TF and presented an increased or decreased expression level in roots from non-inoculated plants transformed with OE_FUL or RNAi_AGL construct, respectively. Our work contributes to defining novel transcriptional regulators for the common bean - rhizobia N-fixing symbiosis, a relevant process for sustainable agriculture.

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The common-bean (Phaseolus vulgaris), a widely consumed legume, originated in Mesoamerica and expanded to South America, resulting in the development of two geographically distinct gene pools. Poor soil condition, including metal toxicity, are often constraints to common-bean crop production. Several P. vulgaris miRNAs, including miR1511, respond to metal toxicity. The MIR1511 gene sequence from the two P. vulgaris model sequenced genotypes revealed that, as opposed to BAT93 (Mesoamerican), the G19833 (Andean) accession displays a 58-bp deletion, comprising the mature and star miR1511 sequences. Genotyping-By-Sequencing data analysis from 87 non-admixed Phaseolus genotypes, comprising different Phaseolus species and P. vulgaris populations, revealed that all the P. vulgaris Andean genotypes and part of the Mesoamerican (MW1) genotypes analyzed displayed a truncated MIR1511 gene. The geographic origin of genotypes with a complete versus truncated MIR1511 showed a distinct distribution. The P. vulgaris ALS3 (Aluminum Sensitive Protein 3) gene, known to be important for aluminum detoxification in several plants, was experimentally validated as the miR1511 target. Roots from BAT93 plants showed decreased miR1511 and increased ALS3 transcript levels at early stages under aluminum toxicity (AlT), while G19833 plants, lacking mature miR1511, showed higher and earlier ALS3 response. Root architecture analyses evidenced higher tolerance of G19833 plants to AlT. However, G19833 plants engineered for miR1511 overexpression showed lower ALS3 transcript level and increased sensitivity to AlT. Absence of miR1511 in Andean genotypes, resulting in a diminished ALS3 transcript degradation, appears to be an evolutionary advantage to high Al levels in soils with increased drought conditions.

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Several environmental stresses generate high amounts of reactive oxygen species (ROS) in plant cells, resulting in oxidative stress. Symbiotic nitrogen fixation (SNF) in the legume-rhizobia symbiosis is sensitive to damage from oxidative stress. Active nodules of the common bean (Phaseolus vulgaris) exposed to the herbicide paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride hydrate), which stimulates ROS accumulation, exhibited reduced nitrogenase activity and ureide content. We analyzed the global gene response of nodules subjected to oxidative stress using the Bean Custom Array 90K, which includes probes from 30,000 expressed sequence tags (ESTs). A total of 4280 ESTs were differentially expressed in stressed bean nodules; of these, 2218 were repressed. Based on Gene Ontology analysis, these genes were grouped into 42 different biological process categories. Analysis with the PathExpress bioinformatic tool, adapted for bean, identified five significantly repressed metabolic pathways related to carbon/nitrogen metabolism, which is crucial for nodule function. Quantitative reverse transcription (qRT)-PCR analysis of transcription factor (TF) gene expression showed that 67 TF genes were differentially expressed in nodules exposed to oxidative stress. Putative cis-elements recognized by highly responsive TF were detected in promoter regions of oxidative stress regulated genes. The expression of oxidative stress responsive genes and of genes important for SNF in bacteroids analyzed in stressed nodules revealed that these conditions elicited a transcriptional response.

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